Kaiser Bottom Fish OnlineFree trialNew StuffHow It WorksContact UsTerms of UseHome
Specializing in Canadian Stocks
SearchAdvanced Search
Welcome Guest User   (more...)
Home / Education
Education
 

SDLRC - Scientific Articles all years by Author - A-An


The Sheahan Diamond Literature Reference Compilation
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcementscalled the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Resource Center
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Media/Corporate References by Name for all years
A B C D-Diam Diamonds Diamr+ E F G H I J K L M N O P Q R S T U V W X Y Z
Tips for Users
Posted/Published Reference CodesThe SDLRC provides 3 types of references identified in the reference code. DS for scientific article, DM for a media article, and DC for a corporate announcement. Consider DS0512-0001. The DS stands for "diamond scientific". 05 stands for 2005, the year the reference was posted. 12 represents the month the reference was posted. For all years prior to 2015 the default month is 12. -0001 is the reference's identifier and it does not mean anything. The number below the refence code, ie 2015, is the year the article was published. Note that the posted year may sometimes be later than the published year.
Sort OrderReferences are sorted by the "author" name and when the reference was posted to the compilation.
Most RecentIf the reference code is highlighted yellow, the reference was made available through the most recent monthly compilation of new literature. Use this to check out new references. When new references are posted, we make it our priority to track down an online link and obtain an abstract. With regard to older references, tracking down an abstract and an online link is a work in progress.
Link to external location of article: If the title has a link, it means we have found a location online where you can either retrieve the full article free, or purchase access to it. The Sheahan Diamond Literature Service is not a technical article procurement service; if you want a restricted article, you must deal directly with the vendor who controls the copyright to the article.
Searching this page for a specific term or authorIn your Firefox browser click Edit in the menu bar and then Find. In the Find box that shows up at the bottom of the web page enter your search term. Firefox will highlight all occurrences. This is particularly helpful when the author you are seeking was not the lead author by whom the compilation is sorted.
Sending or sharing a referenceThe left column (Posted/Published) has an embedded hyperlink for each reference. In Firefox, if you right click on it, you can obtain the link url for that reference's location within the page, which you can copy and paste into an email or any other document. You can also use the "share this link" option to tweet, facebook etc the link.
Author Index
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years - A-An
Posted/
Published
AuthorTitleSourceRegionKeywords
DS202007-1178
2020
ASoltys, A., Giuliani, A,m Phillips, D., Kamenetsky, V.S.Kimberlite metasomatism of the lithosphere and the evolution of olivine in carbonate rich melts evidence from the Kimberley kimberlites ( South Africa).Journal of Petrology, 10.1093/petrology /egaa062/5857610 90p. PdfAfrica, South Africadeposit - Kimberley

Abstract: Olivine is the most abundant phase in kimberlites and is stable throughout most of the crystallisation sequence, thus providing an extensive record of kimberlite petrogenesis. To better constrain the composition, evolution, and source of kimberlites we present a detailed petrographic and geochemical study of olivine from multiple dyke, sill, and root zone kimberlites in the Kimberley cluster (South Africa). Olivine grains in these kimberlites are zoned, with a central core, a rim overgrowth, and occasionally an external rind. Additional ‘internal’ and ‘transitional’ zones may occur between the core and rim, and some samples of root zone kimberlites contain a late generation of high-Mg olivine in cross-cutting veins. Olivine records widespread pre-ascent (proto-)kimberlite metasomatism in the mantle including: (a) Relatively Fe-rich (Mg# <89) olivine cores interpreted to derive from the disaggregation of kimberlite-related megacrysts (20% of cores); (b) Mg-Ca-rich olivine cores (Mg# >89; >0.05?wt.% CaO) suggested to be sourced from neoblasts in sheared peridotites (25% of cores); (c) transitional zones between cores and rims probably formed by partial re-equilibration of xenocrysts (now cores) with a previous pulse of kimberlite melt (i.e., compositionally heterogeneous xenocrysts); and (d) olivine from the Wesselton water tunnel sills, internal zones (I), and low-Mg# rims, that crystallised from a kimberlite melt that underwent olivine fractionation within the shallow lithospheric mantle. Magmatic crystallisation begins with internal olivine zones (II), which are common but not ubiquitous in the Kimberley olivine. These zones are euhedral, contain rare inclusions of chromite, and have a higher Mg# (90.0 ± 0.5), NiO, and Cr2O3 contents, but are depleted in CaO compared to the rims. Internal olivine zones (II) are interpreted to crystallise from a primitive kimberlite melt during its ascent and transport of olivine toward the surface. Their compositions suggest assimilation of peridotitic material (particularly orthopyroxene) and potentially sulfides prior to or during crystallisation. Comparison of internal zones (II) with liquidus olivine from other mantle-derived carbonate-bearing magmas (i.e., orangeites, ultramafic lamprophyres, melilitites) show that low (100×) Mn/Fe (?1.2), very low Ca/Fe (?0.6), and moderate Ni/Mg ratios (?1.1) appear to be the hallmarks of olivine in melts derived from carbonate-bearing garnet-peridotite sources. Olivine rims display features indicative of magmatic crystallisation, which are typical of olivine rims in kimberlites worldwide - i.e. primary inclusions of chromite, Mg-ilmenite and rutile, homogeneous Mg# (88.8 ± 0.3), decreasing Ni and Cr, increasing Ca and Mn. Rinds and high-Mg olivine are characterised by extreme Mg-Ca-Mn enrichment and Ni depletion, and textural relationships indicate these zones represent replacement of pre-existing olivine, with some new crystallisation of rinds. These zones likely precipitated from evolved, oxidised, and relatively low-temperature kimberlite fluids after crustal emplacement. In summary, this study demonstrates the utility of combined petrography and olivine geochemistry to trace the evolution of kimberlite magmatic systems from early metasomatism of the lithospheric mantle by (proto-)kimberlite melts, to crystallisation at different depths en route to surface, and finally late-stage deuteric/hydrothermal fluid alteration processes after crustal emplacement.
DS202010-1845
2020
AGordeychik, B., Churikova, T., Shea, T., Kronz, A,m Simakin, A., Worner, G.Fo and Ni relations in olivine differentiate between crystallization and diffusion trends.Journal of Petrology, 10.1093/petrology/egaa083Mantleolivine

Abstract: Nickel is a strongly compatible element in olivine, and thus fractional crystallization of olivine typically results in a concave-up trend on a Fo-Ni diagram. "Ni-enriched" olivine compositions are considered those that fall above such a crystallization trend. To explain Ni-enriched olivine crystals, we develop a set of theoretical and computational models to describe how primitive olivine phenocrysts from a parent (high-Mg, high-Ni) basalt re-equilibrate with an evolved (low-Mg, low-Ni) melt through diffusion. These models describe the progressive loss of Fo and Ni in olivine cores during protracted diffusion for various crystal shapes and different relative diffusivities for Ni and Fe-Mg. In the case when the diffusivity of Ni is lower than that for Fe-Mg interdiffusion, then olivine phenocrysts affected by protracted diffusion form a concave-down trend that contrasts with the concave-up crystallization trend. Models for different simple geometries show that the concavity of the diffusion trend does not depend on the size of the crystals and only weakly depends on their shape. We also find that the effect of diffusion anisotropy on trend concavity is in the same magnitude as the effect of crystal shape. Thus, both diffusion anisotropy and crystal shape do not significantly change the concave-down diffusion trend. Three-dimensional numerical diffusion models using a range of more complex, realistic olivine morphologies with anisotropy corroborate this conclusion. Thus, the curvature of the concave-down diffusion trend is mainly determined by the ratio of Ni and Fe-Mg diffusion coefficients. The initial and final points of the diffusion trend are in turn determined by the compositional contrast between mafic and more evolved melts that have mixed to cause disequilibrium between olivine cores and surrounding melt. We present several examples of measurements on olivine from arc basalts from Kamchatka, and several published olivine datasets from mafic magmas from non-subduction settings (lamproites and kimberlites) that are consistent with diffusion-controlled Fo-Ni behaviour. In each case the ratio of Ni and Fe-Mg diffusion coefficients is indicated to be?
DS202201-0027
2021
A, F.Mukakami, M., Goncharov, A,F., Miyajimac, N., Yamazakid, D., Holtgrewe, N.Radiative thermal conductivity of single-crystal bridgmanite at the core-mantle boundary with implications for thermal evolution of the Earth.Earth and Planetary Science Letters, Vol. 578, 9p. PdfMantlebridgmanite

Abstract: The Earth has been releasing vast amounts of heat from deep Earth's interior to the surface since its formation, which primarily drives mantle convection and a number of tectonic activities. In this heat transport process the core-mantle boundary where hot molten core is in direct contact with solid-state mantle minerals has played an essential role to transfer thermal energies of the core to the overlying mantle. Although the dominant heat transfer mechanisms at the lowermost mantle is believed to be both conduction and radiation of the primary lowermost mantle mineral, bridgmanite, the radiative thermal conductivity of bridgmanite has so far been poorly constrained. Here we revealed the radiative thermal conductivity of bridgmanite at core-mantle boundary is substantially high approaching to ?5.3±1.2 W/mK based on newly established optical absorption measurement of single-crystal bridgmanite performed in-situ under corresponding deep lower mantle conditions. We found the bulk thermal conductivity at core-mantle boundary becomes ?1.5 times higher than the conventionally assumed value, which supports higher heat flow from core, hence more vigorous mantle convection than expected. Results suggest the mantle is much more efficiently cooled, which would ultimately weaken many tectonic activities driven by the mantle convection more rapidly than expected from conventionally believed thermal conduction behavior.
DS202006-0946
2020
A, V.Ponomarchuk, V.A., Dobretsov, N.L. , Lazareva, E.V., Zhmodik, S.M., Karmanov, N.S., Tolstov, A,V., Pyryaev, A.N.Evidence of microbial-induced mineralization in rocks of the Tomtor carbonatite complex ( Arctic Siberia).Doklady Earth Science, Vol. 490, 2, pp. 76-80.Russia, Siberiacarbonatite

Abstract: Carbonates of the Tomtor complex of ultramafic alkaline rocks and carbonatites (the northern part of the Republic of Sakha Yakutia) are distinguished by a wide range of carbon isotopic composition ?13C from +2 to -59.9‰. The geological position, localization patterns, mineral and chemical compositions and the relationship with REE mineralization of samples with values of ?13C carbonates from -25 to -59‰ are characterized. The formation of abnormally low ?13C in carbonates is determined by the biogenic oxidation of methane from ?13Cmet to -70‰.
DS200812-0641
2008
A.Lee, C-T A., Luffi, P., Hoink, T., Li, Z-X.,A., Lenardic, A.The role of serpentine in preferential craton formation in the late Archean by lithosphere underthrusting.Earth and Planetary Science Letters, Vol. 269, 1-2, May 15, pp. 96-104.MantleGeochronology - cratons
DS202001-0035
2019
A.Reina, G., Zhao, Li. Bianco, A., Komatsu, N.Chemical functionalization of nanodiamonds: opportunities and challenges ahead.Angewandte Chemie International edition, Vol. 58, 50, pp. 17918-17929.Globalnanodiamond

Abstract: Nanodiamond(ND)?based technologies are flourishing in a wide variety of fields spanning from electronics and optics to biomedicine. NDs are considered a family of nanomaterials with an sp3 carbon core and a variety of sizes, shapes, and surfaces. They show interesting physicochemical properties such as hardness, stiffness, and chemical stability. Additionally, they can undergo ad?hoc core and surface functionalization, which tailors them for the desired applications. Noteworthy, the properties of NDs and their surface chemistry are highly dependent on the synthetic method used to prepare them. In this Minireview, we describe the preparation of NDs from the materials?chemistry viewpoint. The different methodologies of synthesis, purification, and surface functionalization as well as biomedical applications are critically discussed. New synthetic approaches as well as limits and obstacles of NDs are presented and analyzed.
DS202010-1833
2020
A.Clerici, A.M.C., Gomes, C.B.. De Min, A., Comin-Chiaramnti, P.Heavy minerals in the sediments from Paraguay rivers as indicators for diamond occurrences.Bol. Mus. Nac. Hist. Paraguay, , Vol. 20, 2, pp. 188-204. pdfSouth America, Paraguaygeochemistry

Abstract: After some works of Jaime Baez-Presse that quoted the presence of diamonds in Eastern Paraguay, we have perfprmed a whole sampling a study relative to the indicator mineral for diamonds. Indicator minerals are mineral species that, when appearing as transported grains in clastic sediments, indicate the presence in bedrock of a specific type of mineralization, hydrothermal alteration or lithology. Their physical and chemical characteristics, including a relatively high density (heavy minerals), facilitate their preservation and identification. The heavy minerals represent an important exploration method for detecting a variety of ore deposit types including diamond, gold, Ni-Cu, PGE, and so on.. One of the most significant events in the application of indicator mineral methods in the past was the diamond exploration. This paper provides an overview of indicator mineral methods, i.e. presence of Cr-diopside, Pyrope-rich garnet and Picroilmenite, for diamond exploration along the Eastern Paraguay river. Unfortunately the above heavy mineraks, generally associated to the diamonds, do not appear in Eastern Paraguay, excluding this Country as a potential source for the diamond as economic potential source.
DS202001-0012
2019
A., McCausland< P.Gauthier, M.S., Hodder, T., Ross, M., Kelley, S.E. Rochester, A., McCausland< P. The subglacial mosaic of the Laurentide ice sheet; a study of the interior region of southwestern Hudson Bay.Quaternary Science Reviews, Vol. 214, pp. 1-27.Canada, Manitobageomorphology

Abstract: Reconstructions of past ice-flow provide useful insights into the long-term behaviour of past ice sheets and help to understand how glaciated landscapes are shaped. Here, we present reconstruction of a 10-phase ice-flow history from southwestern Hudson Bay in northeastern Manitoba (Canada), a dynamic region situated between two major ice dispersal centres of the Laurentide Ice Sheet. We utilize a diverse geologic dataset including 1900 field-based erosional indicators, 12 streamlined-landform flowsets, esker and meltwater corridor orientations, 103 till-fabrics analyses, and 1344 till-clast lithology counts. Our reconstruction suggests that both pre-MIS 2 and MIS 2 glaciations followed similar growth patterns, where ice advanced into study area from ice centered to the east (probably in northern Quebec), followed by a switch in ice-flow direction indicating flow from the Keewatin ice centre to the northwest and north. The cause for this switch in ice-flow orientation is uncertain, but the youngest switch may relate to retreat of ice during MIS 3 that then left space for Keewatin-sourced ice to advance over the study area. While modelling experiments indicate widespread cold-based conditions in the study area during the last glacial cycle, uniformly relict landscapes are not common. Instead, the glaciated landscape is palimpsest and commonly fragmented, forming a subglacial bed mosaic of erosional and depositional assemblages that record both shifting ice-flow direction through time and shifting subglacial conditions. Each assemblage formed, or modified, during times of dynamic (warm-based) ice, and later preserved under conditions below or close to the pressure melting point (slow and sluggish, or cold-based).
DS1860-0327
1880
A.H. Smith And CoA.H. Smith And CoA Short Sketch of the African Diamond MinesA.h. Smith And Co., 12P.Africa, South AfricaMineralogy, Morphology
DS1975-0902
1979
A.O. Australia Pty. LtdA.O. Australia Pty. LtdEl 1626, El 1627, El 1629, El 1630, El 1649, El 1651, El 1704, El 1705 Final Report 1977-1979.Northern Territory Geological Survey Open File Report, No. CR 80/031, 11P.Australia, Northern TerritoryProspecting, Geochemistry, Sampling
DS1975-0903
1979
A.O. Australia Pty. LtdA.O. Australia Pty. LtdEl 1768 Annual Report on Exploration for Period Ending 5/12/79.Northern Territory Geological Survey Open File Report, No. CR 80/101, 17P.Australia, Northern TerritoryProspecting, Sampling, Geophysics
DS201806-1229
2018
Aadhiseshan, K.R.Jayananda, M., Santosh, M., Aadhiseshan, K.R.Formation of Archean (3600-2500 Ma) continental crust in the Dharwar craton, southern India.Earth Science Reviews, Vol. 181, pp. 12-42.Indiageodynamics

Abstract: The generation, preservation and destruction of continental crust on Earth is of wide interest in understanding the formation of continents, cratons and supercontinents as well as related mineral deposits. In this contribution, we integrate the available field, petrographic, geochronologic, elemental Nd-Hf-Pb isotope data for greenstones, TTG gneisses, sanukitoids and anatectic granites from the Dharwar Craton (southern India). This review allows us to evaluate the accretionary processes of juvenile crust, mechanisms of continental growth, and secular evolution of geodynamic processes through the 3600-2500?Ma window, hence providing important insights into building of continents in the Early Earth. The Dharwar Craton formed by assembly of micro-blocks with independent thermal records and accretionary histories. The craton can be divided into three crustal blocks (western, central and eastern) separated by major shear zones. The western block contains some of the oldest basement rocks with two generations of volcano-sedimentary greenstone sequences and discrete potassic plutons whereas the central block consist of older migmatitic TTGs, abundant younger transitional TTGs, remnants of ancient high grade supracrustal rocks, linear volcanic-dominated greenstone belts, voluminous calc-alkaline granitoids of sanukitoid affinity and anatectic granites. In contrast, the eastern block comprises younger transitional TTGs, abundant diatexites, thin volcanic-sedimentary greenstone belts and calc-alkaline plutons. Published geochronologic data show five major periods of felsic crust formation at ca. 3450-3300?Ma, 3230-3150?Ma, 3000-2960?Ma, 2700-2600?Ma, and 2560-2520?Ma which are sub-contemporaneous with the episodes of greenstone volcanism. U-Pb ages of inherited zircons in TTGs, as well as detrital zircons together with Nd-Pb-Hf isotope data, reveal continental records of 3800-3600?Ma. The U-Pb zircon data suggest at least four major reworking events during ca. 3200?Ma, 3000?Ma, 2620-2600?Ma, and 2530-2500?Ma corresponding to lower crustal melting and spatially linked high grade metamorphic events. The TTGs are sub-divided into the older (3450-3000?Ma) TTGs and the younger (2700-2600?Ma) transitional TTGs. The older TTGs can be further sub-divided into low-Al and high-Al groups. Elemental and isotopic data suggest that the low-Al type formed by melting of oceanic island arc crust within plagioclase stability field. In contrast, the elemental and isotopic features for the high-Al group suggest derivation of their magmatic precursor by melting of oceanic arc crust at deeper levels (55-65?km) with variable garnet and ilmenite in residue. The transitional TTGs likely formed by melting of composite sources involving both enriched oceanic arc crust and sub-arc mantle with minor contamination of ancient crustal components. The geochemical and isotopic compositions of granitoids with sanukitoid affinity suggest derivation from enriched mantle reservoirs. Finally, anatectic granites were produced by reworking of crustal sources with different histories. In the light of the data reviewed in this contribution, we propose the following scenario for the tectonic evolution of the Dharwar Craton. During 3450-3000?Ma, TTGs sources (oceanic arc crust) formed by melting of down going slabs and subsequent melting of such newly formed crust at different depths resulted in TTG magmas. On the contrary, by 2700?Ma the depth of slab melting increased. Melting of slab at greater depth alongside the detritus results in enriched melts partly modified the overlying mantle wedge. Subsequent melting of such newly formed enriched oceanic arc crust and surrounding arc-mantle generated the magmatic precursor to transitional TTGs. Finally at ca. 2600-2560?Ma, eventual breakoff of down going slab caused mantle upwelling which induced low degree (10-15%) melting of overlying enriched mantle at different depths, thereby, generating the sanukitoid magmas which upon emplacement into the crust caused high temperature metamorphism, reworking and final cratonization.
DS201012-0395
2010
Aanyu, K.Koehm, D., Lindenfeld, M., Rumpker, G., Aanyu, K., Haines, S., Passchier, C.W., Sachu, T.Active transgression faults in rift transfer zones: evidence for complex stress fields and implications for crustal fragmentation processes in the western branchInternational Journal of Earth Sciences, Vol. 99, 7, pp. 1633-1642.Africa, East AfricaEast African Rift
DS201012-0444
2010
Aanyu, K.Link, K., Koehm, D., Barth, M.G., Tiberindwa, J.V., Barifaijo, E., Aanyu, K., Foley, S.F.Continuous cratonic crust between the Congo and Tanzania blocks in western Uganda.International Journal of Earth Sciences, Vol. 99, 7, pp. 1559-1573.Africa, Uganda, TanzaniaGeophysics - seismics
DS201612-2350
2016
Aarab, E.M.Youbi, N., Ernst, R.E., Soderlund, U., Boumehdi, M.A., Bensalah, M.K., Aarab, E.M.Morocco, North Africa: a dyke swarm bonanza.Acta Geologica Sinica, Vol. 90, July abstract p. 15.Africa, MoroccoDykes
DS1975-0513
1977
Aarden, H.M.Garcia, V., Aarden, H.M.Analysis Preliminar de Correlaciones Y Agrupaciones Geo-quimicas En Lateritas Del Cerro Impacto, Estado Bolivar.Fith. Congreso Geologico Venezolano, PP. 941-946.South America, VenezuelaLaterite, Geochemistry, Analyses
DS2001-0626
2001
Aaro, S.Korje, A., Heikkinen, P., Aaro, S.Crustal structure of the northern Baltic Sea paleoriftTectonophysics, Vol. 331, No. 4, Feb. 28, pp. 341-58.Baltic SeaTectonics - rifting
DS1995-1538
1995
Aaros, S.Raisanen, M.L., Tarvainen, T., Aaros, S.NORMA - a program to calculate a normative mineralogy for glacial tills and rocks from chemical analysis.Gff., Vol. 117, pp. 215-224.GlobalGeomorphology, Computer Program - NORMA.
DS1994-0001
1994
Ababou, R.Ababou, R., Bagtzoglou, A.C., Wood, E.F.On the condition number of covariance matrices in kriging, estimation, and simulation of random fieldsMathematical Geology, Vol. 26, No. 1, pp. 99-133GlobalGeostatistics, Kriging
DS2000-0157
2000
Abaca-Hernandez, F.Chica-Olmo, M., Abaca-Hernandez, F.Computing geostatistical image texture for remotely sensed dat a classification.Computers and Geosciences, Vol. 26, No. 4, Apr. pp. 373-84.GlobalComputer - Program, Remote sensing - not specific to diamond
DS201312-0741
2013
Abad, I.Reolid, M., Sacchez-Gomez, M., Abad, I., Gomez-Sanchez, M.E., de Mora, J.Natural monument of the Volcano of Cancarix, Spain: a case of lamproite phreatomagmatic volcanism.Geoheritage, Vol. 5, 1, pp. 35-45.Europe, SpainLamproite
DS201212-0270
2012
Abad, J.D.Guneralp, I., Abad, J.D., Zolezzi, G., Hooke, J.Advances and challenges in meandering channels research.Geomorphology, Vol. 163-164, pp. 1-9.TechnologyMeandering channels - issue (not specific to diamonds)
DS201504-0204
2015
Abakumov, A.M.Kaminsky, F.V., Ryabchikov, I.D., McCammon, C.A., Longo, M., Abakumov, A.M., Turner, S., Heidari, H.Oxidation potential in the Earth's lower mantle as recorded by ferropericlase inclusions in diamond.Earth and Planetary Science Letters, Vol. 417, pp. 49-56.South America, BrazilDeposit - Juina
DS1995-0001
1995
Abalos, B.Abalos, B., Cusi, J.D.Correlation between seismic anisotropy and major geological structures in southwest Liberia: a case study on continental lithosphere deformation.Tectonics, Vol. 14, No. 4, Aug. pp. 1021-40.GlobalLithosphere, tectonics
DS2003-0876
2003
Abart, R.Markl, G., Abart, R., Vennemann, T., Sommer, H.Mid-crustal metasomatic reaction veins in a spinel peridotiteJournal of Petrology, Vol. 44, 6, pp. 1097-1120.MantleBlank
DS200412-1226
2003
Abart, R.Markl, G., Abart, R., Vennemann, T., Sommer, H.Mid-crustal metasomatic reaction veins in a spinel peridotite.Journal of Petrology, Vol. 44, 6, pp. 1097-1120.MantleMetasomatism
DS200912-0599
2009
Abart, R.Prenzel, J., Abart, R., Keller, L.Complex chemical zoning in eclogite facies garnet reaction rims: the role of grain boundary diffusion.Mineralogy and Petrology, Vol. 95, 3-4, pp. 303-313.TechnologyMineral chemistry
DS201012-0255
2010
Abart, R.Guzmics, T., Mitchell, R.H., Szabo, C., Berkesi, M., Milke, R., Abart, R.Carbonatite melt inclusions in coexisting magnetite, apatite and monticellite in Kerimasi calciocarbonatite, Tanzania: melt evolution and petrogenesis.Contributions to Mineralogy and Petrology, Vol. 161, 2, pp. 177-196.Africa, TanzaniaCarbonatite
DS201112-0675
2011
Abart, R.Milke, R., Abart, R., Keller, L., Rhede, D.The behaviour of Mg, Fe, and Ni during the replacement of olivine by orthopyroxene: experiments relevant to mantle metasomatism.Mineralogy and Petrology, In press available, 8p.MantleMetasomatism
DS201112-0676
2011
Abart, R.Milke, R., Abart, R., Keller, L., Rhede, D.The behaviour of Mg, Fe and Ni during the replacement of olivine by orthopyroxene: experiments relevant to mantle metasomatism.Mineralogy and Petrology, In press available, 8p.MantlePeridotite, xenoliths
DS1991-1368
1991
Abate, R.Popplewell, G., Abate, R.The application of modular plants to diamond recovery #1The Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Session, Vol. 84, No. 947, March p. 99. AbstractGlobalDiamond recovery, Mining applications-processing
DS1991-0001
1991
Abate, R.L.Abate, R.L.Ore designed modular plants for small scale mining operations in Third World countriesInstitute of Mining and Metallurgy (IMM) Newsletter, December pp. 19-21AfricaDiamond recovery, Sortex, alluvial mining
DS1993-0002
1993
Abate, R.L.Abate, R.L.The design and development of modular process plants for small scale diamond mining operations #1Prospectors and Developers Diamond Workshop, held March 27th, Toronto, 7pSouth AfricaMining, Processing plants
DS1994-0002
1994
Abate, R.L.Abate, R.L.The design and development of modular process plants for small scale diamond mining operations #2The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Section, p. 69. abstractNorthwest TerritoriesMining, Mineral processing plants
DS1997-0002
1997
Abate, R.L.Abate, R.L.A review of marine diamond mining and processing. Points of interest28th. Annual Underwater Mining Institute, 6p.South Africa, NamibiaMarine mining, Overview
DS201507-0333
2015
Abazova, Z.M.Sazonova, L.V., Nosova, A.A., Kargin, A.V., Borisovskiy, S.E., Tretyachenko, V.V., Abazova, Z.M., Griban, Yu.G.Olivine from the Pionerskaya and V. Grib kimberlite pipes, Arkangelsk diamond province, Russia: types, composition, and origin.Petrology, Vol. 23, 3, pp. 227-258.RussiaDeposit - Grib
DS2002-1460
2002
Abbaschian, R.Shigley, J.E., Abbaschian, R., Clarke, C.Gemesis laboratory created diamonds. a study of the jewelry quality yellow synthetic diamonds being grown on a commercial scale by Genesis Corp. Sarasota FloridaGems & Gemology, Vol. 38, 4, pp. 301-310.GlobalDiamond - synthesis, Economics
DS1998-0001
1998
Abbasi, K.Abbasi, K.uranium-lead (U-Pb) zircons dates from lower crustal xenoliths, State Line kimberlitedistrict, Colorado.Geological Society of America (GSA) Annual Meeting, abstract. only, p.A352.ColoradoGeochronology, State Line District
DS1992-0001
1992
Abbey, S.Abbey, S.Evaluation and application of reference materials for the analysis of rock sand mineralsChemical Geology, Vol. 95, No. 1-2, January 1, pp. 123-130GlobalGeochemistry -analysis, Rocks and minerals -overview
DS1988-0221
1988
Abbinett, D.Forsyth, D.A., Thomas, M.D., Broome, J., Abbinett, D., Halpenny, J.Regional geophysics of the central metasedimentary beltGeological Society of America (GSA) Abstract Volume, Vol. 20, No. 5, March p. 344. abstractGlobalBlank
DS1990-0485
1990
Abbinett, D.Forsyth, D.A., Pilkington, M., Grieve, R.A.F., Abbinett, D.Major circular structure beneath southern Lake Huron defined from potential field dataGeology, Vol. 18, No. 8, August pp. 773-777Ontario, Great LakesGeophysics -aeromagnetics, Tectonics
DS201810-2292
2018
Abbo, A.Abbo, A., Avigad, D., Gerdes, A.The lower crust of the Northern broken edge of Gondwana: evidence for sediment subduction and syn-Variscan anorogenic imprint from zircon U-Pb-Hf granulite xenoliths.Gondwana Research, Vol. 64, pp. 84-96.Europesubduction

Abstract: The continental basement in the Eastern Mediterranean represents the northern edge of Gondwana, which has been the site of repeated crustal accretion and has subsequently been modified by consecutive rifting events. We investigated the geologic and thermal history of the North Gondwana lower crust by examining the U-Pb-Hf isotope systematics in zircons within 6 mafic granulite xenoliths from Pliocene lava cone in North Israel. The lava cone protrudes through the platform cover that seals the late Neoproterozoic junction between the Arabian-Nubian basement to the South and the Cadomian basement exposed in the Taurides to the North. The mafic granulite xenoliths are composed of plagioclase + orthopyroxene + clinopyroxene ± garnet ± spinel ± secondary amphibole. U-Pb zircon ages from the granulites vary among the different samples with distinct zircon age populations at 400-1200 Ma, 170-350 Ma, and 3.6-4.2 Ma, attesting the lower crust preserves a prolonged thermal and igneous history. While 400-550 Ma U-Pb ages are interpreted to be the result of Pb loss, the wide scatter of zircon grains aged between 550 and 1200 Ma, alongside their diverse ?Hf(t) values (?25-+10), is an extraordinary evidence for the accretion of Neoproterozoic sediments into the North Gondwana arc root lower crust. The U-Pb-Hf signature of these zircons resembles Cadomian sediments of the Tauride block to the north, indicating southward (present coordinates) subduction under North Gondwana and possible accretion of fore-arc sediments to the lower crust through relamination in the latest Neoproterozoic. One xenolith contained metamorphic-shaped zircons aged 170-350 Ma with positive ?Hf values and Hf-TDM of 0.85 Ga interpreted to reflect Paleozoic recycling of the Neoproterozoic juvenile Arabian basement, which we consider to form a major component of the lower crust in the region. An overwhelming cluster of Carboniferous zircons concentrating at 305 Ma with exclusively negative ?Hf values around ?6, was retrieved from three xenoliths. Some of these zircons portrayed igneous textures and shape. While Carboniferous igneous activity is the hallmark of Western Europe's Variscan orogeny, the latter did not affect the southern rifted edge of Neo-Tethys where our xenoliths were retrieved. The Paleozoic age-Hf composition in our xenoliths is therefore interpreted to result from syn-Variscan recycling of Neoproterozoic sedimentary remains in the lower crust, and some degree of melting in a non-orogenic environment. Rather than with horizontal plate motions and orogeny, the Carboniferous zircon ages in the xenoliths appear to coalesce with significant vertical movements that created continental scale unconformities and a broad basin and swell architecture known to develop over the entire North Gondwana margin at that time. The Carboniferous aged zircons in northern Israel lower crustal xenoliths are therefore a unique gauge of the thermal perturbation that accompanied the large-scale mantle dynamics below the then passive North African margin of Gondwana, while Variscan orogenic accretion occurred on the Eurasian margin. These lower crustal granulites xenoliths therefore contain important information with respect to the nature of the lower crust under Israel, with implications on the geodynamic setting during the Cadomian and Variscan cycles.
DS2001-1157
2001
AbbottThorkelson, FD.J., Mortensen, Creaser, Davidson, AbbottEarly Proterozoic magmatism in Yukon: constraints on the evolution of northwestern Laurentia.Canadian Journal of Earth Science, Vol. 38, No. 10, Oct. pp. 1479-94.YukonMagmatism - not specific to diamonds
DS1970-0458
1972
Abbott, A.L.Abbott, A.L.Gem Trails of CaliforniaAnaheim: Privately Publishing, 84P.CaliforniaKimberlite
DS202003-0367
2020
Abbott, B.W.Turetsky, M.R., Abbott, B.W., Jones, M.C., Walter Anthony, K.. Olefeldt, D., Schuur, E.A.G., Grosse, G., Kuhry, P., Higelius, G., Koven, C., Lawrence, D.M., Gibson, C., Sannel, A.B.K., McGuire, A.D.Carbon release through abrupt permafrost thaw. ( not specific to diamonds but interest)Nature Geoscience, Vol. 13, pp. 138-143.Mantlecarbon

Abstract: The permafrost zone is expected to be a substantial carbon source to the atmosphere, yet large-scale models currently only simulate gradual changes in seasonally thawed soil. Abrupt thaw will probably occur in <20% of the permafrost zone but could affect half of permafrost carbon through collapsing ground, rapid erosion and landslides. Here, we synthesize the best available information and develop inventory models to simulate abrupt thaw impacts on permafrost carbon balance. Emissions across 2.5?million?km2 of abrupt thaw could provide a similar climate feedback as gradual thaw emissions from the entire 18?million?km2 permafrost region under the warming projection of Representative Concentration Pathway 8.5. While models forecast that gradual thaw may lead to net ecosystem carbon uptake under projections of Representative Concentration Pathway 4.5, abrupt thaw emissions are likely to offset this potential carbon sink. Active hillslope erosional features will occupy 3% of abrupt thaw terrain by 2300 but emit one-third of abrupt thaw carbon losses. Thaw lakes and wetlands are methane hot spots but their carbon release is partially offset by slowly regrowing vegetation. After considering abrupt thaw stabilization, lake drainage and soil carbon uptake by vegetation regrowth, we conclude that models considering only gradual permafrost thaw are substantially underestimating carbon emissions from thawing permafrost.
DS1989-0001
1989
Abbott, D.Abbott, D., Anders, M.Identifying Precambrian hotspots: the Limpopo beltEos, Vol. 70, No. 43, October 24, p. 1357. AbstractSouthern AfricaBeitbridge, Diamonds
DS1990-0101
1990
Abbott, D.Abbott, D., Menke, W.Length of the global plate boundary at 2.4 GaGeology, Vol. 18, No. 1, January pp. 58-61GlobalCraton, Size of the plates
DS1992-0002
1992
Abbott, D.Abbott, D.Sailing continents: the extent of >1.6 1.8 Ga basementEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 323MantleKimberlite, lamproite, Xenoliths
DS1994-0003
1994
Abbott, D.Abbott, D., Burgess, L., Longhi, J., Smith, W.H.F.An empirical thermal history of the Earth's upper mantleJournal of Geophy. Res., Vol. 99, No. B7, July 10, pp. 13, 385-13, 850.MantleGeothermometry
DS1994-0004
1994
Abbott, D.Abbott, D., Drury, R., Smith, W.H.F.Flat to steep transition in subduction styleGeology, Vol. 22, No. 10, October pp. 937-940MantleSubduction
DS1994-0005
1994
Abbott, D.Abbott, D., Drury, R., Smith, W.H.F.Flat to steep transition in subduction styleGeology, Vol. 22, No. 10, October pp. 937-940.MantleTectonics, Subduction
DS1995-0002
1995
Abbott, D.Abbott, D., Mooney, W.The structural and geochemical evolution of the continental crust -support for oceanic plateau model.Review Geophysics, Vol. 33, No. 5, pp. 231-242.MantleGeochemistry, Crust -structure
DS1996-1181
1996
Abbott, D.Riccardi, K., Abbott, D.Increased mantle convection during the Mid Cretaceous- a comparative studyof mantle potential temperature.Journal of Geophysical Research, Vol. 101, No. B4, April 10, pp. 8673-8684.MantleSubduction
DS1996-1377
1996
Abbott, D.Stoddart, P.R., Abbott, D.Influence of the tectonsphere upon plate motionJournal of Geophysical Research, Vol. 101, No. B3, March 10, pp. 5425-33.MantleTectonics
DS1998-0002
1998
Abbott, D.Abbott, D., Mooney, W., Sparks, D.Growth rate of early continents from two parameters: crustal thickness and depleted mantle thickness.Geological Society of America (GSA) Annual Meeting, abstract. only, p.A207.MantleArchean
DS1998-1031
1998
Abbott, D.Mooney, W.D., Abbott, D.The formation of continental crust and lithosphere: a synthesis based on seismic reflection profiling...Geological Society of America (GSA) Annual Meeting, abstract. only, p.A109.MantleTectonic, Lithoprobe
DS1999-0223
1999
Abbott, D.Franco, H., Abbott, D.Gravity signatures of terrane accretionLithos, Vol. 46, pp. 5-16.MantleGeophysics - gravity, Tectonics - not specific to diamonds
DS2000-0001
2000
Abbott, D.Abbott, D., Sparks, D., Herzberg, C., Mooney, W., et al.Quantifying Precambrian crustal extraction: the root is the answerTectonophysics, Vol. 322, No. 1-2, pp.163-90.MantleTectonics - root
DS2001-0205
2001
Abbott, D.Condie, K.C., Des Marais, D.J., Abbott, D.Precambrian superplumes and supercontinents: a record in black shales, carbon isotopes and paleoclimates.Precambrian Research, Vol. 106, No. 3-4, Mar. 1, pp. 239-60.MantleHot spots
DS1996-0001
1996
Abbott, D.G.Abbott, D.G., Camp, D.C.The use of new microtunneling technology to escavate hard rock in a miningapplicationSociety for Mining, Metallurgy and Exploration (SME)-American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, 96-19United StatesMining, Underground
DS1996-0002
1996
Abbott, D.H.Abbott, D.H.Plumes and hotspots as sources of greenstone beltsLithos, Vol. 37, No. 2/3, April pp. 113-128MantleGreenstone belts, Plumes, hotspots
DS1997-0003
1997
Abbott, D.H.Abbott, D.H., Drury, R., Mooney, W.D.Continents as lithological icebergs: the importance of buoyant lithospheric roots.Earth and Planetary Science Letters, Vol. 149, No. 1-4, pp. 15-27.MantleTectonics, Subduction, mantle, Lithospheric roots, Continental Crust
DS1997-0004
1997
Abbott, D.H.Abbott, D.H., Drury, R., Mooney, W.D.Continents as lithological icebergs: the importance of bouyant lithosphericroots.Earth and Planetary Science Letters, Vol. 149, pp. 15-27.Russia, Europe, UralsSubduction, plumes, Oceanic crust
DS2000-0002
2000
Abbott, D.H.Abbott, D.H.Do large impacts strengthen mantle plumes and produce komatiites?Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-314.MantleImpacts
DS2002-0002
2002
Abbott, D.H.Abbott, D.H., Isley, A.E.The intensity, occurrence and duration of superplume events and eras over geological time.Journal of Geodynamics, Vol.34, 2, Sept. pp. 265-307.GlobalTectonics, Geochronology
DS2002-0003
2002
Abbott, D.H.Abbott, D.H., Isley, A.E.Extraterrestrial influence on mantle plume activityEarth and Planetary Science Letters, Vol. 205, 1-2, pp. 53-62.MantleHot spots, plumes
DS2002-0004
2002
Abbott, D.H.Abbott, D.H., Isley, A.E.The intensity, occurrence and duration of superplume events and eras over geological timeJournal of Geodynamics, Vol. 34, 2, pp. 265-307.MantleTectonics
DS2002-0751
2002
Abbott, D.H.Isley, A.E., Abbott, D.H.Implications of the temporal distribution of high Mg magmas for mantle plume volcanism through time.Journal of Geology, Vol.110, 2, pp. 141-58.MantleMagmatism, high magnesium magmas, Plume - hot spots
DS2002-0752
2002
Abbott, D.H.Isley, A.E.,Abbott, D.H.Implications of the temporal distribution of high Mg magmas for mantle plume volcanism through time.Journal of Geology, Vol.110,No.2,pp.141-58.GlobalUltramafics, komatiites, meimcheites, picrites, Plume - time series, geochronology
DS2003-1390
2003
Abbott, D.H.Trubitsyb, V.P., Mooney, W.D., Abbott, D.H.Cold cratonic roots and thermal blankets: how continents affect mantle convectionInternational Geology Review, Vol. 45, 6, pp. 479-96.MantleTectonics
DS2003-1392
2003
Abbott, D.H.Trubitsyn, V.P., Mooney, W.D., Abbott, D.H.Cold cratonic roots and thermal blankets: how continents affect mantle convectionInternational Geology Review, Vol. 45, 6, June pp. 479-96.MantleConvection, Geothermometry
DS200412-2015
2003
Abbott, D.H.Trubitsyn, V.P., Mooney, W.D., Abbott, D.H.Cold cratonic roots and thermal blankets: how continents affect mantle convection.International Geology Review, Vol. 45, 6, pp. 479-96.MantleTectonics
DS201312-0001
2013
Abbott, D.H.Abbott, D.H., Mooney, W.D., Van Tongeron, J.A.The character of the Moho and lower crust within Archean cratons and the tectonic implications.Tectonophysics, Vol. 609, pp. 690-705.Africa, South Africa, ZimbabweKaapvaal Craton
DS1995-0003
1995
Abbott, G.Abbott, G.Overview of MDD field trip to northeast Russia in September 1994The Gangue, No. 47, Jan. pp. 1, 3-5, 8RussiaFieldtrip overview
DS200412-1771
2004
Abbott, G.Schwab, D.L., Thorkelson, D.J., Mortensen, J.K., Creaser, R.A., Abbott, G.The Bear River dykes (1265-1269) Ma): westward continuation of the Mackenzie dyke swarm into Yukon, Canada.Precambrian Research, Vol. 133, no. 3-4, Aug. 20, pp.175-186.Canada, YukonDyke swarms, geochronology
DS1993-0003
1993
Abbott, R.Abbott, R., Champigny, N.Implementing management systems... EMS (environmental management system)Mining Environmental Management, pp. 4, 5CanadaEnvironmental, Management systems
DS1997-0005
1997
Abbott, R.M.Abbott, R.M.Strategic mining environmental managementNorth American Mining, June pp. 16-17United StatesMining - environment, Legal
DS1900-0284
1905
Abbott, W.J.L.Abbott, W.J.L.Gemmological Tables for the Use of Diamond and Gem Merchants; Jewellers and Students.London:, 4 SHEETS.GlobalDiamond Cutting, Standards
DS1996-0720
1996
Abbruzzi, J.M.Kay, S.M., Abbruzzi, J.M.Magmatic evidence for Neogene lithospheric evolution of the central Andean'flat-slab' between 30 and 23 deg S.Tectonophysics, Vol. 259, No. 1-3, June 30, pp. 15-28Andes, Cordillera, Bolivia, ArgentinaSubduction, Tectonics
DS1996-0873
1996
Abbruzzi, J.M.Mahlburg Kay, S., Orrell, S., Abbruzzi, J.M.Zircon and whole rock neodymium lead isotopic evidence for a Grenville age and a Laurentian Origin for the basementJournal of Geology, Vol. 104, No. 6, Nov. pp. 637-648ArgentinaGeochronology, Precordillera
DS201412-0088
2014
Abdallah, N.Caby, R., Bruguier, O., Fernandez, L., Hammor, D., Bosch, D., Mechati, M., Laouar, R., Ouabadi, A., Abdallah, N., Douchet, C.Metamorphic diamonds in a garnet megacryst from the Edough Massif (northeastern Algeria)… Recognition and geodynamic consequences.Tectonophysics, Vol. 637, pp. 341-353.Africa, AlgeriaEdough Massif
DS201709-1965
2017
Abdallah, N.Bruguier, O., Bosch, D., Caby, R., Vitale-Brovarone, A., Fernadez, L., Hammor, D., Laouar, R., Ouabadi, A., Abdallah, N., Mechanti, M.Age of UHP metamorphism in the Western Mediterranean: insight from rutile and minute zircon inclusions in a diamond bearing garnet megacryst ( Edough Massif, NE Algeria).Earth and Planetary Science Letters, Vol. 474, pp. 215-225.Africa, Algeriadiamond inclusions

Abstract: Diamond-bearing UHP metamorphic rocks witness for subduction of lithospheric slabs into the mantle and their return to shallow levels. In this study we present U-Pb and trace elements analyses of zircon and rutile inclusions from a diamond-bearing garnet megacryst collected in a mélange unit exposed on the northern margin of Africa (Edough Massif, NE Algeria). Large rutile crystals (up to 300 ?m in size) analyzed in situ provide a U-Pb age of 32.4 ± 3.3 Ma interpreted as dating the prograde to peak subduction stage of the mafic protolith. Trace element analyses of minute zircons (?30 ?m) indicate that they formed in equilibrium with the garnet megacryst at a temperature of 740-810 °C, most likely during HP retrograde metamorphism. U-Pb analyses provide a significantly younger age of 20.7 ± 2.3 Ma attributed to exhumation of the UHP units. This study allows bracketing the age of UHP metamorphism in the Western Mediterranean Orogen to the Oligocene/early Miocene, thus unambiguously relating UHP metamorphism to the Alpine history. Exhumation of these UHP units is coeval with the counterclockwise rotation of the Corsica-Sardinia block and most likely resulted from subduction rollback that was driven by slab pull.
DS201909-2105
2019
Abdallisamed, M-I-M.Wang, L-X., Ma, C-Q., Salih, M-A., Abdallisamed, M-I-M., Zhu, Y-X.The syenite-carbonatite-fluorite association in Jebel Dumbier complex ( Sudan): magma origin and evolution.Goldschmidt2019, 1p. Poster abstractAfrica, Sudancarbonatite

Abstract: Jebel Dumbier is the first-identified carbonatite-bearing alkaline complex in Sudan. It is located on the northeastern margin of the Nuba Mountains in the south part of Sudan. The complex exposed as small elliptical hills with outcrops of around 8 km2. It is composed of dominant orthoclasite and ditroite and subdominant carbonatite and fluorite dykes. The fluorite dykes are mined and together with the carbonatite dykes are controlled by a NNE strike-slip fault system. Orthoclasite is the dominant rock type, comprising of orthoclase, kalsilite, few interstitial biotite and calcium carbonate and accesserary minerals of fluorite, apatite and zircon. Ditroite consists of perthite, aegirine-augite, nepheline, sodalite, and minor annite-phlogopite and richterite, with common accessories of fluorite, titanite, apatite and zircon. Zircon U-Pb dating reveals that both orthoclasite and ditroite emplaced at around 600 Ma. Relative to orthoclasites, ditroites display higher FeOtotal and MgO and lower Al2O3 contents, contain higher volatiles (F, Cl, Br, S), and are more depleted in LILEs (Rb, Sr, Ba) and enriched in HFSEs (Nb, Ta, Zr, Hf, Th, U) and REEs. Isotopic data imply that the ditoite, orthoclasite, fluorite and carbonatite dyke originated from a common source of depleted mantle affinities, with identical low initial 87Sr/86Sr ratios (0.7033-0.7037) and high ?Nd (t) values (1.6-2.7). The carbonatites display ?13C(V-PDB) of -5.8 to -6.7‰ and ?18O(SMOW) of 9.1 to 11.3‰, typical of primary igneous carbonatite worldwide. We propose that the orthoclasite, ditroite, carbonatite, and fluorite association in Jebel Dumbier is product of variable degrees of fractional crystallization of mantlederived volatile-rich magma. Magma immiscibility among silicates, carbonates and fluorates may proceed. The Jebel Dumbier alkaline-carbonatite complex represents the postorogenic alkaline magmatism during the end evolution of Pan-African orogen (650-550 Ma) at Arabian-Nubian Shield.
DS202004-0500
2020
Abdeina, E.H.Ba, M.H., Ibough, H., Lo, K., Youbi, N., Jaffal, M., Ernst, R.E., Niang, A.J., Dia, I., Abdeina, E.H., Bensalah, M.K., Boumehdi, M.A., Soderlund, U.Spatial and temporal distribution patterns of Precambrian mafic dyke swarms in northern Mauritania ( West African Craton): analysis and results fro remote sensing interpretation, geographical information systems ( GIS), Google Earth TM images, and regionaArabian Journal of Geosciences, Vol. 13, , 209 orchid.org/ 0000-002-3287-9537Africa, Mauritaniacraton

Abstract: We used remote sensing, geographical information systems, Google Earth™ images, and regional geology in order to (i) improve the mapping of linear structures and understand the chronology of different mafic dyke swarms in the Ahmeyim area that belongs to the Archean Tasiast-Tijirit Terrane of the Reguibat Shield, West African craton, NW Mauritania. The spatial and temporal distributions with the trends of the dyke swarms provide important information about geodynamics. The analysis of the mafic dyke swarms map and statistical data allow us to distinguish four mafic dyke swarm sets: a major swarm trending NE-SW to NNE-SSW (80%) and three minor swarms trending EW to ENE-WSW (9.33%), NW-SE to WNW-ESE (9.06%), and NS (1.3%). The major swarms extend over 35 km while the minor swarms do not exceed 13 km. The Google Earth™ images reveal relative ages through crossover relationships. The major NE-SW to NNE-SSW and the minor NS swarms are the oldest generations emplaced in the Ahemyim area. The NW-SE-oriented swarm dykes which are cutting the two former swarms are emplaced later. The minor E-W to WSW-ENE swarms are probably the youngest. A precise U-Pb baddeleyite age of 2733?±?2 Ma has been obtained for the NNE-SSW Ahmeyim Great Dyke. This dyke is approximately 1500 m wide in some zone and extends for more than 150 km. The distinct mafic dyke swarms being identified in this study can potentially be linked with coeval magmatic events on other cratons around the globe to identify reconstructed LIPs and constrain continental reconstructions.
DS202005-0717
2020
Abdel Halim, A.H.Abdel Halim, A.H., Helmy, H.H., Elhaddad, M.A., El-Mahallawi, M., Mogessie, A.Petrology of a Neoproteroxoic mantle peridotite-chromitite association from Abu Dahr area, eastern Egypt Desert, Egypt: infiltration of boninitic melt in highly depleted harzburgite.Journal of African Earth Sciences, Vol. 165, 18p. PdfAfrica, EgyptBoninite

Abstract: Peridotites of Abu Dahr represent the main litho-unit of a Neoproterozoic dismembered ophiolite sequence and are among the best-preserved and well-exposed mantle rocks in South Eastern Desert of Egypt. Here, we present new geochemical and mineral chemical data for peridotites and associated pyroxenites and for chromitites and their platinum-group minerals to constrain their petrogenesis and geotectonic setting. The Abu Dahr ophiolite mantle section consists mainly of harzburgites, cut by pyroxenite dykes and containing dunite-chromitite lenses. The harzburgites are composed of olivine, orthopyroxene, spinel and minor clinopyroxene (?1.0 vol %) and amphibole. Olivine from harzburgites is highly magnesian (Fo 91-93) and Cr-spinel shows a wide-range of Cr2O3 and Al2O3 contents. The enstatite component of orthopyroxene decreases from harzburgite (En = 90-91) to orthopyroxenite (En = 84-87). Amphiboles are represented by magnesiohornblende and tschermakite. The chromitites are massive to disseminated and composed of magnesiochromite with high Cr# (83-93) and Mg# (66-79), and low TiO2 (<0.1 wt%) content. Solid inclusions in chromite include olivine, orthopyroxene and hornblende. Laurite (RuS2) is the most common PGM detected in the investigated chromitite samples and forms micrometer-size inclusions in fresh chromite. Various Ni-sulfides are found both in fresh chromite and along serpentine veinlets. Harzburgites have a refractory composition with a very low Al2O3 (0.4-0.8 wt%) and CaO (0.2-1.6 wt%) contents and high bulk-rock Mg# (89-92). Geochemical data suggest that the Abu Dahr peridotites are highly depleted SSZ peridotites formed in a forearc mantle wedge setting by high degrees of hydrous partial melting and emplaced as a result of the collision of the intra-oceanic arc with the Beitan gneisses. The podiform chromitites and orthopyroxenites were formed due to impregnation of mantle wedge harzburgites by boninitic melt. The highly depleted nature of the harzburgite is responsible for the small reserves of chromite ore at Abu Dahr and in the South Eastern Desert in general.
DS1993-0004
1993
Abdel Raman, E.M.Abdel Raman, E.M., et al.A new ophiolite occurrence in northwest Sudan - contraints on late Proterozoictectonism.Terra Nova, Vol. 2, pp. 363-76.GlobalTectonics, Ultramafic volcanism.
DS201412-0001
2014
Abdelfadil, K.M.Abdelfadil, K.M., Romer, R.L., Glodny, J.Mantle wedge metasomatism revealed by Li isotopes in orogenic lamprophyres. ( Bohemian Massif)Lithos, Vol. 196-197, pp. 14-26.EuropeLamprophyre
DS201312-0002
2013
Abdelfadil, Kh.M.Abdelfadil, Kh.M., Romer, R.L., Seifert, Th., Lobst, R.Calc-alkaline lamprophyres from Lusatia ( Germany) - evidence for a repeatedly enriched mantle source.Chemical Geology, Vol. 353, pp. 230-245.Europe, GermanyLamprophyre
DS2003-0001
2003
Abdelrahman, E.Abdelrahman, E., El-Araby, T., Essa, K.A least square minimisation approach to depth, index parameter and amplitudeExploration Geophysics, (Australian Bulletin), Vol. 34, No. 4, Dec. pp. 241-248.GlobalBlank
DS200412-0001
2003
Abdelrahman, E.M.Abdelrahman, E.M., El Araby, T.M., Essa, K.S.A least squares minimisation approach to depth, index parameter, and amplitude coefficient determination from magnetic anomaliesExploration Geophysics, Vol. 34, pp. 241-248.TechnologyGeophysics - magnetics, dykes, ( not specific to diamon
DS200712-0001
2007
Abdelrahman, E.M.Abdelrahman, E.M., Abo-Ezz, E.R., Soliman, K.S., El-Araby, T.M., Essa, K.S.A least squares window curve method for interpretation of magnetic anomalies caused by dipping dikes.Pure and Applied Geophysics, Vol. 164, 5, May pp. 1027-1044.CanadaGeophysics - airborne magnetics
DS2002-0005
2002
Abdelrahman, E.S.M.Abdelrahman, E.S.M., El Araby, H.M., El Araby, T.M., Essa, K.S.A new approach to depth determination from magnetic anomaliesGeophysics, Vol. 67, 5, pp. 1524-31.GlobalGeophysics - magnetics not specific to diamonds
DS1994-0006
1994
Abdel-Rahman, A.F.M.Abdel-Rahman, A.F.M.Nature of biotites from alkaline, calc-alkaline and peraluminous magmasJournal of Petrology, Vol. 35, No. 2, April pp. 525-542GlobalMagmatism, Mineral chemistry -biotites
DS1994-0007
1994
Abdel-Rahman, A.F.M.Abdel-Rahman, A.F.M.Alkali amphibole: a potential source of rare earth elements in felsicalkaline rocks.Exploration and Mining Geology, Vol. 3, No. 2, April pp. 81-94.Quebec, Labrador, California, Nubian ShieldAlkaline rocks, Deposit -Oka
DS201712-2667
2018
Abdelsalam, G.Abdelsalam, G., Atekwana, E., Elsenbeck, J., Jones, A.G., Chikambwe, E.Imaging Precambrian lithospheric structure in Zambia using electromagnetic methods.Gondwana Research, Vol. 54, pp. 38-49.Africa, Zambia, Malawigeophysics

Abstract: The Precambrian geology of eastern Zambia and Malawi is highly complex due to multiple episodes of rifting and collision, particularly during the formation of Greater Gondwana as a product of the Neoproterozoic Pan-African Orogeny. The lithospheric structure and extent of known Precambrian tectonic entities of the region are poorly known as there have been to date few detailed geophysical studies to probe them. Herein, we present results from electromagnetic lithospheric imaging across Zambia into southern Malawi using the magnetotelluric method complemented by high-resolution aeromagnetic data of the upper crust in order to explore the extent and geometry of Precambrian structures in the region. We focus particularly on determining the extent of subcontinental lithospheric mantle (SCLM) beneath the Archean-Paleoproterozoic cratonic Bangweulu Block and the Mesoproterozoic-Neoproterozoic Irumide and Southern Irumide Orogenic Belts. We also focus on imaging the boundaries between these tectonic entities, particularly the boundary between the Irumide and Southern Irumide Belts. The thickest and most resistive lithosphere is found beneath the Bangweulu Block, as anticipated for stable cratonic lithosphere. Whereas the lithospheric thickness estimates beneath the Irumide Belt match those determined for other orogenic belts, the Southern Irumide Belt lithosphere is substantially thicker similar to that of the Bangweulu Block to the north. We interpret the thicker lithosphere beneath the Southern Irumide Belt as due to preservation of a cratonic nucleus (the pre-Mesoproterozoic Niassa Craton). A conductive mantle discontinuity is observed between the Irumide and Southern Irumide Belts directly beneath the Mwembeshi Shear Zone. We interpret this discontinuity as modified SCLM relating to a major suture zone. The lithospheric geometries determined from our study reveal tectonic features inferred from surficial studies and provide important details for the tectonothermal history of the region.
DS2003-0763
2003
Abdelsalam, M.Kusky, T.M., Abdelsalam, M., Tucker, R.D., Stern, R.J.Evolution of the East African and related orogens, and the assembly of GondwanaPrecambrian Research, Vol. 123, 2-4, pp. 81-85.Gondwana, East Africa, TanzaniaBlank
DS200412-1072
2003
Abdelsalam, M.Kusky, T.M., Abdelsalam, M., Tucker, R.D., Stern, R.J.Evolution of the East African and related orogens, and the assembly of Gondwana.Precambrian Research, Vol. 123, 2-4, pp. 81-85.Gondwana, East Africa, TanzaniaTectonics
DS1996-0003
1996
Abdelsalam, M.G.Abdelsalam, M.G.Suture and shear zones in the Arabian Nubian shieldJournal of African Earth Sciences, Vol. 23, No. 3, Oct. 1, pp. 289-310Africa, Saudi Arabia, SudanTectonics, Arabian-Nubian shield
DS2002-0006
2002
Abdelsalam, M.G.Abdelsalam, M.G., Liegeois, J.P., Stern R.J.The Saharan metacratonJournal of African Earth Sciences, Vol.34, No.3-4,April-May pp. 119-36.AfricaTectonics, Craton
DS201112-0001
2011
Abdelsalam, M.G.Abdelsalam, M.G., Gao, S.S., Liegeois, J-P.Upper mantle structure of the Sahara metacraton.Journal of African Earth Sciences, Vol. 60, 5, pp. 328-336.AfricaUpper mantle structure, convection
DS201212-0407
2013
Abdelsalam, M.G.Liegeois, J-P., Abdelsalam, M.G., Ennih, N., Ouabadi, A.Metacraton: nature, genesis and behaviour.Gondwana Research, Vol. 23, 1, pp. 220-237.TechnologySubduction
DS201705-0832
2017
Abdelsalam, M.G.Goussi Ngalamo, J.F., Bisso, D., Abdelsalam, M.G., Atekwana, E.A., Katumwehe, A.B., Ekodeck, G.E.Geophysical imaging of metacratonization in the northern edge of the Congo craton in Cameroon.Journal of African Earth Sciences, Vol. 129, pp. 94-107.Africa, CameroonCraton, Congo

Abstract: We used the World Gravity Map (WGM 2012) data to investigate the Archean Congo craton and the Oubanguides orogenic belt in Cameroon. The Oubanguides orogenic belt constitutes, from northwest to southeast, the Neoproterozoic West Cameroon domain, the Paleoproterozoic-Neoproterozoic Adamawa-Yade domain, and the dominantly Neoproterozoic Yaoundé domain (the crustal expression of the suture zone between the Congo craton and the orogenic terranes). We analyzed the WGM 2012 data to identify different gravity anomalies. We also applied the two-dimensional (2D) radially-averaged power spectral analysis to the WGM 2012 data to estimate the Moho depth. Additionally, we developed a 2D forward gravity model along a Nsbnd S profile to image the lithospheric structure of the Precambrian entities. We found that: (1) the Congo craton, the Yaoundé domain, the southeastern part of the West Cameroon domain, and the northern part of the Adamawa-Yade domain are characterized by low gravity anomaly. (2) the southern part of the Adamawa-Yade domain is marked by a pronounced E-W trending high gravity anomaly. (3) the crust is thicker beneath the Congo craton, the Yaoundé domain and the southern part of the Adamawa-Yade domain. (4) the presence of a denser lower crust material beneath the southern part of the Adamawa-Yade domain. We propose that this denser crustal material is an under-thrusted portion of the Congo craton that has been densified through metacratonization processes that accompanied collision between the craton and the orogenic terranes. This is in good agreement with geological and geochemical observations indicating that the northern edge of the Congo craton and the Adamawa-Yade domain had undergone metacratonization during the Neoproterozoic. Our suggestion is also in good agreement with observations which show that the margins of many cratons worldwide have been decratonized due to subduction processes. Our work highlights the importance of potential field geophysical data in mapping the metacratonized margins of cratons.
DS201801-0055
2018
Abdelsalam, M.G.Sarfian, E., Evans, R.L, Abdelsalam, M.G., Atekwana, E., Elsenbeck, J., Jones, A.G., Chikambwe, E..Imaging Precambrian lithospheric structure in Zambia using electromagnetic methods.Gondwana Research, Vol. 54, pp. 38-49.Africa, Zambiageophysics -em
DS201802-0263
2018
Abdelsalam, M.G.Sarafian, E., Evans, R.L., Abdelsalam, M.G., Atekwana, E., Elsenbeck, J., Jones, A.G., Chikambwe, E.Imaging Precambrian lithospheric structure in Zambia using electromagnetic methods.Gondwana Research, Vol. 54, pp. 38-49.Africa, Zambiageophysics

Abstract: The Precambrian geology of eastern Zambia and Malawi is highly complex due to multiple episodes of rifting and collision, particularly during the formation of Greater Gondwana as a product of the Neoproterozoic Pan-African Orogeny. The lithospheric structure and extent of known Precambrian tectonic entities of the region are poorly known as there have been to date few detailed geophysical studies to probe them. Herein, we present results from electromagnetic lithospheric imaging across Zambia into southern Malawi using the magnetotelluric method complemented by high-resolution aeromagnetic data of the upper crust in order to explore the extent and geometry of Precambrian structures in the region. We focus particularly on determining the extent of subcontinental lithospheric mantle (SCLM) beneath the Archean-Paleoproterozoic cratonic Bangweulu Block and the Mesoproterozoic-Neoproterozoic Irumide and Southern Irumide Orogenic Belts. We also focus on imaging the boundaries between these tectonic entities, particularly the boundary between the Irumide and Southern Irumide Belts. The thickest and most resistive lithosphere is found beneath the Bangweulu Block, as anticipated for stable cratonic lithosphere. Whereas the lithospheric thickness estimates beneath the Irumide Belt match those determined for other orogenic belts, the Southern Irumide Belt lithosphere is substantially thicker similar to that of the Bangweulu Block to the north. We interpret the thicker lithosphere beneath the Southern Irumide Belt as due to preservation of a cratonic nucleus (the pre-Mesoproterozoic Niassa Craton). A conductive mantle discontinuity is observed between the Irumide and Southern Irumide Belts directly beneath the Mwembeshi Shear Zone. We interpret this discontinuity as modified SCLM relating to a major suture zone. The lithospheric geometries determined from our study reveal tectonic features inferred from surficial studies and provide important details for the tectonothermal history of the region.
DS201809-2021
2018
Abdelsalam, M.G.Fletcher, A.W., Abdelsalam, M.G., Emishaw, L., Atekwana, E.A., Lao-Davila, D.A., Ismail, A.Lithospheric controls on the rifting of the Tanzanian Craton at the Eyasi Basin, eastern branch of the East African Rift system.Tectonics, Aug 14, doi: 10.1029/2018 TC005065Africa, Tanzaniacraton

Abstract: Continental rifts most often nucleate within orogenic belts. However, some studies in the East African Rift System (EARS) have shown that continental rifts can also develop withincratons. This work investigated the ~1.5 Ma Eyasibasin,which propagates in a WSW direction into the Tanzanian craton. The basin is located where the Eastern Branch of the EARS transitions from a narrow rift (~70 km wide) thewider(~300 km wide) North Tanzanian Divergence. Unlike the rest of the Eastern Branch segments, the Eyasibasindoes not follow the Mozambique orogenic belt located on the eastern margin of the Tanzanian craton. This work generatedlithospheric?scale sections across the basinusing: (1) Digital Elevation Model to map surface rift?related brittle structures; (2) Aeromagnetic data to determine the depth to the Precambrian basement;and (3) World Gravity Model 2012 to estimatecrustal and lithospheric thickness by applying the two?dimensional(2D) radially?averaged power spectral analysis and 2D forward gravity modeling. These cross?sectionsshow that the Eyasibasinnucleates within a previously unidentified suture zone within the Tanzanian cratonand that this suture zone is characterized by thinner lithospherethat can be as thin as ~95 km. This zone ofthinner lithosphere is offset southeastwardfrom the surface expression of the Eyasibasinand might have facilitated the formation of other basins further south. Furthermore, the lithospheric thickness map indicates that the Tanzanian craton is heterogeneous and possibly composed of multiplesmaller cratonic fragments.
DS201811-2595
2018
Abdelsalam, M.G.Ngalamo, J.F.G., Sobh, M., Bisso, D., Abdelsalam, M.G., Atekwana, E., Ekodeck, G.E.Lithospheric structure beneath the Central Africa Orogenic Belt in Cameroon from the analysis of satellite gravity and passive seismic data.Tectonophysics, Vol. 745, pp. 326-337.Africa, Cameroongeophysics - seismic

Abstract: We present original results that contribute to the understanding of lithospheric structures modification of regions that have witnessed superimposition of multiple tectonic events throughout their geological history. We analyze satellite gravity data through two-dimensional radially-averaged power spectral analysis as well as passive seismic data through thermal modeling to image the depth to the Moho and the lithosphere - asthenosphere boundary (LAB beneath the Central Africa Orogenic Belt (CAOB). The CAOB is an ENE-trending deformation belt extending from Cameroon in the west to Sudan in the east. In Cameroon, it is found on the northern edge of the Congo craton represented by the Oubanguides orogenic belt (the Western Cameroon, the Adamawa - Yade, and the Yaoundé domains). It coincides with the Adamawa plateau and the Benue Trough, and it is spotted by the Cenozoic Cameroon Volcanic Line (CVL). The CAOB was formed during the Precambrian Greater Gondwana assembly but was reactivated during the Mesozoic as a result of Gondwana breakup. We find deeper Moho and LAB) beneath Congo craton and the Yaoundé domain reaching ~50?km and ~200?km, respectively. We map shallower Moho and LAB beneath the CAOB (together with the Adamawa plateau and the Benue trough) reaching ~25?km and ~70?km, respectively. We interpret the shallower LAB beneath the CAOB as due to zonal sub-continental lithospheric mantle (SCLM) delamination along the northern edge of the Congo craton that occurred in association with collisional assembly of Greater Gondwana. This allowed for channelization of mantle flow during the Cenozoic resulting in the formation of the CVL and the uplift of the Adamawa plateau. Our approach can be used to understand the modification of lithospheric structures beneath other terrains that have long tectonic history.
DS201812-2812
2018
Abdelsalam, M.G.Goussi Ngalamo, J.F., Sobh, M., Bisso, D., Abdelsalam, M.G., Atekwana, E., Ekodeck, G.E.Lithospheric structure beneath the central Africa orogenic belt in Cameroon from the analysis of satellite gravity and passive seismic data.Tectonophysics, Vol. 745, pp. 326-337.Africa, Cameroongeophysics - seismics

Abstract: We present original results that contribute to the understanding of lithospheric structures modification of regions that have witnessed superimposition of multiple tectonic events throughout their geological history. We analyze satellite gravity data through two-dimensional radially-averaged power spectral analysis as well as passive seismic data through thermal modeling to image the depth to the Moho and the lithosphere - asthenosphere boundary (LAB beneath the Central Africa Orogenic Belt (CAOB). The CAOB is an ENE-trending deformation belt extending from Cameroon in the west to Sudan in the east. In Cameroon, it is found on the northern edge of the Congo craton represented by the Oubanguides orogenic belt (the Western Cameroon, the Adamawa - Yade, and the Yaoundé domains). It coincides with the Adamawa plateau and the Benue Trough, and it is spotted by the Cenozoic Cameroon Volcanic Line (CVL). The CAOB was formed during the Precambrian Greater Gondwana assembly but was reactivated during the Mesozoic as a result of Gondwana breakup. We find deeper Moho and LAB) beneath Congo craton and the Yaoundé domain reaching ~50?km and ~200?km, respectively. We map shallower Moho and LAB beneath the CAOB (together with the Adamawa plateau and the Benue trough) reaching ~25?km and ~70?km, respectively. We interpret the shallower LAB beneath the CAOB as due to zonal sub-continental lithospheric mantle (SCLM) delamination along the northern edge of the Congo craton that occurred in association with collisional assembly of Greater Gondwana. This allowed for channelization of mantle flow during the Cenozoic resulting in the formation of the CVL and the uplift of the Adamawa plateau. Our approach can be used to understand the modification of lithospheric structures beneath other terrains that have long tectonic history.
DS201904-0733
2019
Abdelsalam, M.G.Evans, R.L., Elsenbeck, J., Zhu, J., Abdelsalam, M.G., Sarafian, E., Mutamina, D., Chilongola, F., Atekwana, E.A., Jones, A.G.Structure of the lithosphere beneath the Barotse basin, western Zambia, from magnetotelluric data.Tectonics, Vol. 38, 2, pp. 666-686.Africa, Zambiageophysics

Abstract: A magnetotelluric survey in the Barotse Basin of western Zambia shows clear evidence for thinned lithosphere beneath an orogenic belt. The uppermost asthenosphere, at a depth of 60-70 km, is highly conductive, suggestive of the presence of a small amount of partial melt, despite the fact that there is no surface expression of volcanism in the region. Although the data support the presence of thicker cratonic lithosphere to the southeast of the basin, the lithospheric thickness is not well resolved and models show variations ranging from ~80 to 150 km in this region. Similarly variable is the conductivity of the mantle beneath the basin and immediately beneath the cratonic lithosphere to the southeast, although the conductivity is required to be elevated compared to normal lithospheric mantle. In a general sense, two classes of model are compatible with the magnetotelluric data: one with a moderately conductive mantle and one with more elevated conductivities. This latter class would be consistent with the impingement of a stringer of plume?fed melt beneath the cratonic lithosphere, with the melt migrating upslope to thermally erode lithosphere beneath the orogenic belt that is overlain by the Barotse Basin. Such processes are potentially important for intraplate volcanism and also for development or propagation of rifting as lithosphere is thinned and weakened by melt. Both models show clear evidence for thinning of the lithosphere beneath the orogenic belt, consistent with elevated heat flow data in the region.
DS2000-0003
2000
Abdrahmanov, K.A.Abdrahmanov, K.A.New petrologic geodynamic model of diamond bearing magmatic formations And diamond deposit forecast.Igc 30th. Brasil, Aug. abstract only 1p.RussiaMagmatism - lamproite-kimberlite-picrite
DS1998-0003
1998
Abdrakhimov, M.Z.Abdrakhimov, M.Z., Kouznetsova, E.I.Development of intergranular cracking and relaxation of stress in deep crystalline rock of eartb crust ....7th International Kimberlite Conference Abstract, pp. 1-3.RussiaGeochemistry, Physico-chemical influence of water
DS201910-2295
2019
Abdrault, D.Rizo, H., Abdrault, D., Bennett, N.R., Humayun, M., Brandon, A., Vlastelic, I., Moine, B., Poirier, A., Bouhifd, M.A., Murphy, D.T.182W evidence for core-mantle interaction in the source of mantle plumes.Geochemical Perspectives Letters, Vol. 11, pp. 6-11.Mantlemantle plumes, hotspots

Abstract: Tungsten isotopes are the ideal tracers of core-mantle chemical interaction. Given that W is moderately siderophile, it preferentially partitioned into the Earth’s core during its segregation, leaving the mantle depleted in this element. In contrast, Hf is lithophile, and its short-lived radioactive isotope 182Hf decayed entirely to 182W in the mantle after metal-silicate segregation. Therefore, the 182W isotopic composition of the Earth’s mantle and its core are expected to differ by about 200 ppm. Here, we report new high precision W isotope data for mantle-derived rock samples from the Paleoarchean Pilbara Craton, and the Réunion Island and the Kerguelen Archipelago hotspots. Together with other available data, they reveal a temporal shift in the 182W isotopic composition of the mantle that is best explained by core-mantle chemical interaction. Core-mantle exchange might be facilitated by diffusive isotope exchange at the core-mantle boundary, or the exsolution of W-rich, Si-Mg-Fe oxides from the core into the mantle. Tungsten-182 isotope compositions of mantle-derived magmas are similar from 4.3 to 2.7 Ga and decrease afterwards. This change could be related to the onset of the crystallisation of the inner core or to the initiation of post-Archean deep slab subduction that more efficiently mixed the mantle.
DS201012-0358
2010
Abdu, Y.Khomyakov, A.P., Camara, F., Sokolova, E., Abdu, Y., Hawthorne, F.C.Paraershovite, a new mineral species from the Khibin alkaline massif, Kola Peninsula, Russia: description and crystal structure.Canadian Mineralogist, Vol. 48, 2, pp. 291-300.Russia, Kola PeninsulaAlkalic
DS201412-0111
2014
Abdu, Y.Chakhmouradian, A.R., Cooper, M.A., Ball, N., Reguir, E.P., Medici, L., Abdu, Y., Antonov, A.A.Vladykinite Na3Sr4(Fe2+Fe3+)Si8O24: a new complex sheet silicate from peralkaline rocks of the Murun complex, eastern Siberia, Russia.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 5-21TechnologyAlkalic
DS201510-1761
2014
Abdu, Y.Chakhmouradian, A.R., Cooper, M.A., Ball, N., Reguir, E.P., Medici, L., Abdu, Y., Antonov, A.A.Vladykinite, Na3Sr4(Fe2+Fe3+)Si8024: a new complex sheet silicate from peralkaline rocks of the Murun Complex, eastern Siberia, Russia.Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 5-21.Russia, SiberiaDeposit - Murun

Abstract: Vladykinite, ideally Na3Sr4(Fe2+Fe3+)Si8O24, is a new complex sheet silicate occurring as abundant prismatic crystals in a dike of coarse-grained peralkaline feldspathoid syenite in the north-central part of the Murun complex in eastern Siberia, Russia (Lat. 58° 22? 48? N; Long. 119° 03? 44? E). The new mineral is an early magmatic phase associated with aegirine, potassium feldspar, eudialyte, lamprophyllite, and nepheline; strontianite (as pseudomorphs after vladykinite) and K-rich vishnevite are found in the same assemblage, but represent products of late hydrothermal reworking. Vladykinite is brittle, has a Mohs hardness of 5, and distinct cleavage on {100}. In thin section, it is colorless, biaxial negative [a = 1.624(2), b = 1.652(2), g = 1.657(2), 2Vmeas = 44(1)°, 2Vcalc = 45(1)°] and shows an optic orientation consistent with its structural characteristics (X^a = 5.1° in b obtuse, Z^c = 4.7° in b acute, Y = b). The Raman spectrum of vladykinite consists of the following vibration modes (listed in order of decreasing intensity): 401, 203, 465, 991, 968, 915, 348, 167, 129, 264, 1039, and 681 cm–1; O-H signals were not detected. The Mössbauer spectrum indicates that both Fe2+ and Fe3+ are present in the mineral (Fe3+/FeS = 0.47), and that both cations occur in a tetrahedral coordination. The mean chemical composition of vladykinite (acquired by wavelength-dispersive X?ray spectrometry and laser-ablation inductively-coupled-plasma mass-spectrometry), with FeS recast into Fe2+ and Fe3+ in accord with the Mössbauer data, gives the following empirical formula calculated to 24 O atoms: (Na2.45Ca0.56)S3.01(Sr3.81 K0.04Ba0.02La0.02Ce0.01)S3.90(Fe2+0.75Fe3+0.66Mn0.26Zn0.16Al0.12Mg0.05Ti0.01)S2.01(Si7.81Al0.19)S8.00O24. The mineral is monoclinic, space group P21/c, a = 5.21381(13), b = 7.9143(2), c = 26.0888(7) Å, b = 90.3556(7)°, V = 1076.50(5) Å3, Z = 2. The ten strongest lines in the powder X?ray diffraction pattern are [dobs in Å (I) (hkl)]: 2.957 (100) (123, 123); 2.826 (100) (117, 117); 3.612 (58) (114, 114); 3.146 (37) (120); 2.470 (32) (210, 01.10); 4.290 (30) (111, 111); 3.339 (30) (106, 115, 106); 2.604 (28) (200); 2.437 (25) (034); 1.785 (25) (21.10, 234). The structure of vladykinite, refined by single-crystal techniques on the basis of 3032 reflections with Fo > 4sFo to R1 = 1.6%, consists of tetrahedral sheets parallel to (100) and consisting of (Si8O24)16– units incorporating four-membered silicate rings and joined into five- and eight-membered rings by sharing vertices with larger tetrahedra hosting Fe2+, Fe3+, Mn, Zn, Al, Mg, and Ti. Larger cations (predominantly Na, Sr, and Ca) are accommodated in octahedral and square-antiprismatic interlayer sites sandwiched between the tetrahedral sheets. Structural relations between vladykinite and other sheet silicates incorporating four-, five-, and eight-membered rings are discussed. The name vladykinite is in honor of Nikolay V. Vladykin (Vinogradov Institute of Geochemistry, Russia), in recognition of his contribution to the study of alkaline rocks. Holotype and co-type specimens of the mineral were deposited in the Robert B. Ferguson Museum of Mineralogy in Winnipeg, Canada.
DS201602-0241
2015
Abdu, Y.Sokolova, E., Abdu, Y., Hawthorne, F.C., Genovese, A., Camara, F., Khomyakov, A.P.From structure topology to chemical composition. XVIII. Titanium silicates: revision of the crystal structure and chemical formula of Betalomonosovite, a group IV TS-block mineral from the Lovozero alkaline massif, Kola Peninsula.The Canadian Mineralogist, Vol. 53, pp. 401-428.Russia, Kola PeninsulaLovozero Massif

Abstract: The crystal structure of betalomonosovite, ideally Na6?4Ti4(Si2O7)2[PO3(OH)][PO2(OH)2]O2(OF), a 5.3331(7), b 14.172(2), c 14.509(2) Å, ? 103.174(2), ? 96.320(2), ? 90.278(2)°, V 1060.7(4) Å3, from the Lovozero alkaline massif, Kola peninsula, Russia, has been refined in the space group PFormula to R = 6.64% using 3379 observed (Fo > 4?F) reflections collected with a single-crystal APEX II ULTRA three-circle diffractometer with a rotating-anode generator (MoK?), multilayer optics, and an APEX-II 4K CCD detector. Electron-microprobe analysis gave the empirical formula (Na5.39Ca0.36Mn0.04Mg0.01)?5.80 (Ti2.77Nb0.48Mg0.29Fe3+0.23Mn0.20Zr0.02Ta0.01)?4(Si2.06O7)2[P1.98O5(OH)3]O2[O0.82F0.65(OH)0.53]?2, Dcalc. = 2.969 g cm?3, Z = 2, calculated on the basis of 26 (O + F) apfu, with H2O determined from structure refinement. The crystal structure of betalomonosovite is characterized by extensive cation and anion disorder: more than 50% of cation sites are partly occupied. The crystal structure of betalomonosovite is a combination of a titanium silicate (TS) block and an intermediate (I) block. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral) and exhibits linkage and stereochemistry typical for Group IV (Ti + Mg + Mn = 4 apfu) of the TS-block minerals. The I block is a framework of Na polyhedra and P tetrahedra which ideally gives {Na2?4[PO3(OH)][PO2(OH)2]} pfu. Betalomonosovite is an Na-poor OH-bearing analogue of lomonosovite, Na10Ti4(Si2O7)2(PO4)2O4. In the betalomonosovite structure, there is less Na in the I block and in the TS block when compared to the lomonosovite structure. The OH groups occur mainly in the I block where they coordinate P and Na atoms and in the O sheet of the TS block (minor). The presence of OH groups in the I block and in the TS block is supported by IR spectroscopy and bond-valence calculations on anions. High-resolution TEM of lomonosovite shows the presence of pervasive microstructural intergrowths, accounting for the presence of signals from H2O in the infrared spectrum of anhydrous lomonosovite. More extensive lamellae in betalomonosovite suggest a topotactic reaction from lomonosovite to betalomonosovite.
DS201412-0091
2014
Abdu, Y.A.Camara, F., Skolova, E., Abdu, Y.A., Hawthorne, F.C.Nafertisite Na3Fe2 10Ti2(Si6017)02(OH)6F(H2))2 from Mt. Kukisvumchorr Khibiny alkaline massif, Kola Peninsula, Russia: refinement of the crystal structure and revision of the chemical formula.European Journal of Mineralogy, Vol. 26, pp. 689-700.Russia, Kola PeninsulaKhibiniy Massif
DS201512-1903
2015
Abdu, Y.A.Chakhmouradian, A.R., Cooper, M.A., Medici, L., Abdu, Y.A., Shelukhina, Y.S.Anzaite-(Ce), a new rare earth mineral and structure type from the AfrikAnd a silicocarbonatite, Kola Peninsula.Mineralogical Magazine, Vol. 79, 5, pp. 1231-1244.RussiaCarbonatite

Abstract: Anzaite-(Ce), ideally Formula Fe2+Ti6O18(OH)2, is a new, structurally complex mineral occurring as scarce minute crystals in hydrothermally altered silicocarbonatites in the Afrikanda alkali-ultramafic complex of the Kola Peninsula, Russia. The mineral is a late hydrothermal phase associated with titanite, hibschite, clinochlore and calcite replacing the primary magmatic paragenesis. The rare-earth elements (REE) (dominated by Ce), Ti and Fe incorporated in anzaite-(Ce) were derived from primary Ti oxides abundant in the host rock. Anzaite-(Ce) is brittle and lacks cleavage; the density calculated on the basis of structural data is 5.054(6) g cm?3. The mineral is opaque and grey with a bluish hue in reflected light; its reflectance values range from 15-16% at 440 nm to 13-14% at 700 nm. Its infrared spectrum shows a prominent absorption band at 3475 cm?1 indicative of OH? groups. The average chemical composition of anzaite-(Ce) gives the following empirical formula calculated on the basis of 18 oxygen atoms and two OH? groups: (Ce2.18Nd0.85La0.41Pr0.26Sm0.08Ca0.36Th0.01)?4.15Fe0.97(Ti5.68Nb0.22Si0.04)?5.94O18(OH)2. The mineral is monoclinic, space group C2/m, a = 5.290(2), b = 14.575(6), c = 5.234(2) Å, ? = 97.233(7)°, V = 400.4(5) Å3, Z = 1. The ten strongest lines in the X-ray micro-diffraction pattern are [dobs in Å (I) hkl]: 2.596 (100) 002; 1.935 (18) 170; 1.506 (14) 133; 1.286 (13) 1.11.0; 2.046 (12) 2?41; 1.730 (12) 003; 1.272 (12) 0.10.2; 3.814 (11) 1?11; 2.206 (9) 061; 1.518 (9) 172. The structure of anzaite-(Ce), refined by single-crystal techniques to R1 = 2.1%, consists of alternating layers of type 1, populated by REE (+ minor Ca) in a square antiprismatic coordination and octahedrally coordinated Fe2+, and type 2, built of five-coordinate and octahedral Ti, stacked parallel to (001). This atomic arrangement is complicated by significant disorder affecting the Fe2+, five-coordinate Ti and two of the four anion sites. The order-disorder pattern is such that only one half of these positions in total occupy any given (010) plane, and the disordered (010) planes are separated by ordered domains comprising REE, octahedral Ti and two anion sites occupied by O2?. Structural and stoichiometric relations between anzaite-(Ce) and other REE-Ti (±Nb, Ta) oxides are discussed. The name anzaite-(Ce) is in honour of Anatoly N. Zaitsev of St Petersburg State University (Russia) and The Natural History Museum (UK), in recognition of his contribution to the study of carbonatites and REE minerals. The modifier reflects the prevalence of Ce over other REE in the composition of the new mineral.
DS200812-0574
2008
Abduriyim, A.Kitawaki, H., Abduriyim, A., Okano, M.Identification of melee size synthetic yellow diamonds in jewelry.Gems & Gemology, Vol. 44, 3, pp. 202-213.TechnologySynthetics
DS2001-0039
2001
Abe, M.Arai, S., Kida, M., Abe, M., Yurimoto, H.Petrology of peridotite xenoliths in alkali basalt ( 11 Ma) from Boun, Korea: insight into upper mantle....Journal of Min. Petrol. Sciences, Vol. 96, No. 3, pp. 89-99.GlobalMantle mineralogy - East Asian continental margin
DS1995-0054
1995
Abe, N.Arai, S., Abe, N.Reaction of orthopyroxene in peridotite xenoliths with alkali-basalt melt and its implication for alpine crAmerican Mineralogist, Vol. 80, No. 9-10, Sept, Oct pp. 1041-1047.JapanXenoliths
DS1998-0004
1998
Abe, N.Abe, N., Arai, S., Yurimoto, H.Petrology of the arc peridotite xenoliths: implications for geochemical evolution of the wedge mantle.7th International Kimberlite Conference Abstract, pp. 4-6.MantleXenoliths, Subduction
DS2000-0004
2000
Abe, N.Abe, N., Arai, S., Shcheka, S., Yurimoto, H.Petrology of harzburgite and related xenoliths from Avacha volcano, Kamchatka Arc and its implication for..Igc 30th. Brasil, Aug. abstract only 1p.RussiaMantle - wedge mantle processes, Xenoliths
DS2001-0001
2001
Abe, N.Abe, N.Petrochemistry of serpentinized peridotite from the Iberia abyssal plain: its character intermediate ....Geological Society of London Special Publication, No. 187, pp. 143-60.MantleMantle - upper, sub-oceanic - sub-continental
DS2003-0502
2003
Abe, N.Griffin, W.L., O'Reilly, S.Y., Abe, N., Aulbach, S., Davies, R.M., Pearson, N.J.The origin and evolution of Archean lithospheric mantlePrecambrian Research, Vol. 127, 1-2, Nov. pp. 19-41.China, South Africa, Siberia, Northwest Territories, BoGeochemistry, SCLM, continental, Archon, metasomatism
DS200412-0723
2003
Abe, N.Griffin, W.L., O'Reilly, S.Y., Abe, N., Aulbach, S., Davies, R.M., Pearson, N.J., Doyle, B.J.,Kivi, K.The origin and evolution of Archean lithospheric mantle.Precambrian Research, Vol. 127, 1-2, Nov. pp. 19-41.China, Africa, Russia, Canada, Northwest TerritoriesGeochemistry, SCLM, continental, Archon, metasomatism
DS200712-0023
2007
Abe, N.Arai, S., Abe, N., Ishimaru, S.Mantle peridotites from the Western Pacific.Gondwana Research, Vol. 11, 1-2, Jan. pp. 180-199.AsiaPeridotite
DS201701-0027
2016
Abe, N.Pilet, S., Abe, N., Rochat, L., Kaczmarek, M-A., Hirano. N., Machida, S., Buchs, D.M., Baumgartner, P.O., Muntener, O.Pre-subduction metasomatic enrichment of the oceanic lithosphere induced by plate flexure.Nature Geoscience, Vol. 9, pp. 898-903.MantleSubduction

Abstract: Oceanic lithospheric mantle is generally interpreted as depleted mantle residue after mid-ocean ridge basalt extraction. Several models have suggested that metasomatic processes can refertilize portions of the lithospheric mantle before subduction. Here, we report mantle xenocrysts and xenoliths in petit-spot lavas that provide direct evidence that the lower oceanic lithosphere is affected by metasomatic processes. We find a chemical similarity between clinopyroxene observed in petit-spot mantle xenoliths and clinopyroxene from melt-metasomatized garnet or spinel peridotites, which are sampled by kimberlites and intracontinental basalts respectively. We suggest that extensional stresses in oceanic lithosphere, such as plate bending in front of subduction zones, allow low-degree melts from the seismic low-velocity zone to percolate, interact and weaken the oceanic lithospheric mantle. Thus, metasomatism is not limited to mantle upwelling zones such as mid-ocean ridges or mantle plumes, but could be initiated by tectonic processes. Since plate flexure is a global mechanism in subduction zones, a significant portion of oceanic lithospheric mantle is likely to be metasomatized. Recycling of metasomatic domains into the convecting mantle is fundamental to understanding the generation of small-scale mantle isotopic and volatile heterogeneities sampled by oceanic island and mid-ocean ridge basalts.
DS202007-1120
2020
Abe, N.Abe, N., Surour, A.A., Madani, A.A., Arai, S.Metasomatized peridotite xenoliths from the Cretaceous rift related Natash volcanics and their bearing on the nature of the lithospheric mantle beneath the southern part of the eastern desert of Egypt.Lithos, in press available , 47p. PdfAfrica, Asia, Egyptperidotites

Abstract: Highly carbonated mantle xenoliths have been found in rift-related alkaline basalts at the Wadi Natash area in the southern part of the Eastern Desert of Egypt. Although all olivine and most orthopyroxene was replaced by carbonate and/or quartz, textural and mineral chemical features show that they are plagioclase-free spinel peridotites (lherzolite to harzburgite). Cr and Mg numbers (Cr#, Mg#) of Cr-spinel vary from 0.06 to 0.45 and 0.73 to 0.81, respectively. The correlation between Cr# and Mg# of the Cr-spinel in the studied xenoliths is weakly negative and its TiO2 content is slightly higher than in abyssal peridotite that was not affected by melt injection. The chemistry of ortho- and clinopyroxene suggests enstatite and chromian diopside compositions, respectively, with distinct signatures of a sub-continental mantle source. In particular, the Na2O contents (>1.0?wt%) and AlVI/AlIV ratios (1.2-2.6) of chromian diopside suggest such an origin. Two-pyroxene geothermometry indicates a temperature of about 900?°C, which is slightly lower than that of ordinary spinel peridotite xenoliths from other rift zones. It is evident that the studied peridotite xenoliths had experienced mantle processes (e.g. decompression melting, magma upwelling and metasomatism) at higher pressure than abyssal peridotites. The trace-element chemistry of clinopyroxene, e.g. high LREE/HREE ratios {(Ce/Yb)n?=?7}, high LREE contents (>3.6?ppm and up to 30.0?ppm Ce) and high Sr between >85.6?ppm and 466?ppm, indicates metasomatic alteration of the peridotite. Clinopyroxene in one sample has very low Ti/Eu and high LREE/HREE ratios. Clinopyroxene with (Ce/Yb)n higher than 3-4 and Ti/Eu ratio lower than 1500 may have experienced carbonatite or carbonate-rich melt metasomatism prior to their incorporation into the host basalt. The basalt itself is almost devoid of any carbonatization and hence the studied mantle peridotites were carbonatized before the generation of the basaltic magma but following an earlier event of K-metasomatism as indicated by the presence of phlogopite. The studied peridotites from the Wadi Natash area were altered by a carbonate-rich melt during a rifting stage. The results of the present paper indicate that the Natash basalts with their peridotite xenoliths extruded along transversal fractures of the NW-trending Nuqra-Kom Ombo-Kharit continental rift on its western shoulder in the south Eastern Desert of Egypt.
DS1993-0005
1993
Abe, Y.Abe, Y.Physical state of the very early earthLithos, Vol. 30, No. 3-4, Septtember pp. 223-236MantleGeodynamics
DS201012-0276
2010
Abedu, B.Hetman, C.M., Nowicki, T., Freeman, L., Abedu, B.The preliminary geology and evaluation of the Koidu kimberlite dykes, Sierra Leone.International Dyke Conference Held Feb. 6, India, 1p. AbstractAfrica, Sierra LeoneDyke morphology
DS201212-0298
2012
Abedu, B.Hetman, C.M., Freeman, L., Nowicki, T.E., Abedu, B.Internal geology development and emplacement of the K1 kimberlite pipe, Koidu mine, Sierra Leone, West Africa.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, Sierra LeoneDeposit - Koidu
DS201212-0493
2012
Abedu, B.Moss, S., Nowicki, T., Hetman, C., Freeman, L.,Abedu, B.Geology and evaluation of kimberlite dykes at Koidu, Sierra Leone.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, Sierra LeoneDeposit - Koidu
DS201412-0339
2013
Abedu, B.Harder, M., Nowicki, T.E., Hetman, C.M., Freeman, L., Abedu, B.Geology and exploration of the K2 kimberlite, Koidu mine, Sierra Leone, West Africa.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 191-208.Africa, Sierra LeoneDeposit - Koidu (K2)
DS201212-0284
2012
Abedub, B.Harder, M.C., Nowickia, C., Hetman, T.E., Hetmana, D., Freeman, C.M., Abedub, B.Geology and evaluation of the K2 kimberlite, Koidu mine, Sierra Leone, West Africa.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, Sierra LeoneDeposit - K2 Koidu
DS202002-0186
2020
Abel, M.Garcia, L.F., Abel, M., Perrin, M., dos Santis Alvarenga, R.The GeoCore ontology: a core ontology for general use in geology.Computers and Geosciences, Vol. 135, 104387 9p. PdfGlobalGeoCore

Abstract: Domain ontologies assume the role of representing, in a formal way, a consensual knowledge of a community over a domain. This task is especially difficult in a wide domain like Geology, which is composed of diversified science resting on a large variety of conceptual models that were developed over time. The meaning of the concepts used by the various professionals often depends on the particular vision that they have of a domain according to their background and working habits. Ontology development in Geology thus necessitates a drastic elucidation of the concepts and vocabulary used by geologists. This article intends to contribute to solving these difficulties by proposing a core ontology named GeoCore Ontology resting on the BFO top ontology, specially designed for describing scientific fields. GeoCore Ontology contains well-founded definitions of a limited set of general concepts within the Geology field that are currently considered by all geologists whatever their skill. It allows modelers to separately consider a geological object, the substance that constitutes it, the boundaries that limit it and the internal arrangement of the matter inside it. The core ontology also allows the description of the existentially dependent qualities attached to a geological object and the geological process that generated it in a particular geological age. This small set of formally defined and described concepts combined with concepts from BFO provides a backbone for deriving by subsumption more specialized geological concepts and also constitutes a baseline for integrating different existent domain ontologies within the Geology domain. The GeoCore ontology and the methodology that we used for building it, provide solutions for unveiling major misunderstanding regarding the concepts that are commonly used for formulating geological interpretations. This will facilitate the communication of this information to external Geology users and its integration in domain applications.
DS200412-0345
2003
Abello, J.Collins, A.S., Johnson, S., Fitzimmona, I.C.W., Powell, C.McA., Hulscher, B., Abello, J., Razakamana, T.Neoproterozoic deformation in central Madagascar: a structural section through part of the East African orogen.Proterozoic East Gondwana: Supercontinent assembly and Breakup. Ed. Yoshida , Geological Society of London Spe, No. 206, pp. 363-380.Africa, MadagascarPlume, tectonics
DS201903-0507
2019
Abelsalam, M.G.Evans, R.L., Elsenbeck, J., Zhu, J., Abelsalam, M.G., Sarafian, E., Mutamina, D., Chilongola, F., Atekwan, E., Jones, A.G.Structure of the lithosphere beneath the Barotse Basin, western Zambia from magnetotelluric data.Tectonics, in press available Africa, Zambiamelting

Abstract: A magnetotelluric survey in the Barotse Basin of western Zambia shows clear evidence for thinned lithosphere beneath an orogenic belt. The uppermost asthenosphere, at a depth of 60-70 km, is highly conductive, suggestive of the presence of a small amount of partial melt, despite the fact that there is no surface expression of volcanism in the region. Although the data support the presence of thicker cratonic lithosphere to the southeast of the basin, the lithospheric thickness is not well resolved and models show variations ranging from ~80 to 150 km in this region. Similarly variable is the conductivity of the mantle beneath the basin and immediately beneath the cratonic lithosphere to the southeast, although the conductivity is required to be elevated compared to normal lithospheric mantle. In a general sense, two classes of model are compatible with the magnetotelluric data: one with a moderately conductive mantle and one with more elevated conductivities. This latter class would be consistent with the impingement of a stringer of plume?fed melt beneath the cratonic lithosphere, with the melt migrating upslope to thermally erode lithosphere beneath the orogenic belt that is overlain by the Barotse Basin. Such processes are potentially important for intraplate volcanism and also for development or propagation of rifting as lithosphere is thinned and weakened by melt. Both models show clear evidence for thinning of the lithosphere beneath the orogenic belt, consistent with elevated heat flow data in the region.
DS1992-0003
1992
Aber, J.S.Aber, J.S.The glaciation of northeastern KansasBoreas, Vol. 20, No. 4, December 1st. pp. 297-314KansasGeomorphology, Glacial
DS1993-0006
1993
Aber, J.S.Aber, J.S.Glaciotectonics and mapping glacial depositsCanadian Press Research Center, University of Regina, Saskatchewan S4S O42 Payable, 310p. $ 78.00 plus GST etcGlobalGlacial deposits, Geomorphology
DS1993-0007
1993
Aber, J.S.Aber, J.S.Proceedings and field guide of the Inqua Commision on formation and properties of glacial depositsCanadian Plains Research Center, University of Regina, Regina, 310p. approx. $ 75.00Russia, Saskatchewan, GlobalGeomorphology, glacial deposits, Table of contents
DS1995-0004
1995
Aber, J.S.Aber, J.S., Bluemle, J.P., Brighton-Grette, J., et al.Glaciotectonic map of North AmericaGeological Society of America (GSA) Map, No. MCHO79, 1: 6, 500, 000 $ 21.00Canada, United StatesMap, Glaciology, glacial, structures
DS2001-0002
2001
Aber, J.S.Aber, J.S., Aber, S.W.Limestone xenoliths in Hills Pond lamproite, Woodson County, KansasKansas Academy of Science, Vol. 104, No. 1/2, pp. 123-28.KansasLamproite, Deposit - Hills Pond
DS2001-0002
2001
Aber, S.W.Aber, J.S., Aber, S.W.Limestone xenoliths in Hills Pond lamproite, Woodson County, KansasKansas Academy of Science, Vol. 104, No. 1/2, pp. 123-28.KansasLamproite, Deposit - Hills Pond
DS1998-1146
1998
AbercrombiePeirce, J.W., Goussev, Charters, Abercrombie, De PaoliIntrasedimentary magnetization by vertical fluid flow and exotic geochemistry.Leading Edge, Vol. 17, No. 1, pp. 89-92.Alberta, Western CanadaGeophysics - magnetics, Basin
DS1999-0019
1999
AbercrombieArden, K.M., DePaoli, Johnson, Hemstock, AbercrombieMetallic and industrial mineral assessment report on the Athabasca permitsin northeastern Alberta.Alberta Geological Survey, MIN 19990004AlbertaExploration - assessment, Birch Mountain Resources Ltd.
DS1998-0005
1998
Abercrombie, H.Abercrombie, H.Metallic and industrial mineral assessment report on the precious and base metals in northeast Alberta.Alberta Geological Survey, MIN 19980001Alberta, northeastExploration - assessment, Birch Mountain Resources Ltd.
DS1860-0575
1888
Abercromby, R.Abercromby, R.Seas and Skies in Many Latitudes; Or, Wanderings in Search Of Weather.London: E. Stanford., 447P.Africa, South AfricaTravelogue
DS1985-0501
1985
Aberg, G.Nystrom, J.O., Svensson, N.B., Aberg, G.An occurrence of apatite rich rocks of carbonatitic affinity near the Jotnian graben structure in Gavle, central SwedenGeol. Forens, Vol. 107, No. 3, pp. 185-195Sweden, ScandinaviaCarbonatite
DS201709-1975
2017
Abernethy, F.Crosby, J., Mikhail, S., Stuart, F., Abernethy, F.Tracing volatiles in Earth's mantle using He-C-N isotopes in garnet bearing diamondites.Goldschmidt Conference, abstract 1p.Mantlediamondites

Abstract: The origin of diamond-forming carbon in the Earth is unclear [1-3]; sources include subducted organic sediment and primordial mantle carbon. For example, some diamonds contain eclogitic silicate + sufide inclusions and have depleted ?13C (-10 to -30‰), enriched ?15N (+3 to +35‰) values, consistent with subducted crustal material [2-3]. However, some diamonds show mantle-like ?15N (<-5‰) and depleted ?13C values (-10 to -30‰ ) which have been cited as evidence of enstatite chondrite-like primordial C-N sources [1]. The helium isotope composition of mantle rocks are powerful tracers,of Earth’s volatile history because primordial 3He is not recycled back into the mantle. However, there are few He isotope studies of diamond fluids. The 3He/4He of garnetbearing diamondites from the Orapa mine (Botswana) range from 0.1 to 3 Ra [4-5], consistent with a recycled origin. However, our recent work has identified a suite of diamondites with 3He/4He = 0.06 to 8.2 Ra which correlates negatively with ?13C, suggesting that the subduction-related C is associated with mantle 3He/4He ratios. To unravel this complexity we are combining He, C and N isotope analyses in polycrystalline diamond from garnetbearing diamondites from the Orapa mine. These data will also be used to assess the extent to which carbon and nitrogen isotopes are decoupled during diamond-formation [3].
DS201910-2286
2019
Abernethy, F.Mikhail, S., Crosby, J., Stuart, F., Di Nicola, L., Abernethy, F.Helium isotopes reveals what carbon and nitrogen cannot, a mantle component for strongly 13C-depleted diamond.Goldschmidt2019, 1p. AbstractMantlehelium

Abstract: The origin of the diamond-forming fluids are routinely addressed with the stable isotopes of carbon and nitrogen, where average ?13C and ?15N values are -5 ± 3‰ and -5 ± 4‰, respectively. Because these values differ from crustal sources the application of C-N stable isotopes are applied as tracers of recycled crustal volatiles into the mantle. Additionally, fluid inclusions in fast-growing diamonds provides a unique opportunity to further examine the origin of diamond-forming fluids using noble gas geochemistry. Here we combine C-N isotopes, N concentrations from the diamond with He isotopes released from trapped fluids by in vacuo crushing of mg-sized polycrystalline diamonds. The samples examined are dominantly eclogitic to websteritic abd originate from Southern Africa. ?13C values range from -4.3 to -22.2 ‰ and ?15N values from -4.9 to +23.2 ‰. These data require a significant contribution of material that is 13Cdepleted and 15N-enriched relative to mantle, akin to altered oceanic crust or deep ocean sediments. 3He/4He ratios range from typical mantle values (8.5 Ra) to those dominated by radiogenic He (< 0.1 Ra). These new data show 3He/4He correlates with 3He concentration, suggesting that the low 3He/4He are, at least in part, the result of ingrowth of radiogenic 4He in He-poor diamonds after their formation. 13C-depleted and 15N-enriched diamonds dominate the population studied here. This indicates that subducted altered oceanic crust is essential for diamondite-formation within the SCLM beneath southern Africa. However, the fluids trapped in the low ?13C diamondites (< -15 ‰) have 3He/4He ratios that indicate an origin in the convective upper asthenospheric mantle. Ergo, helium reveals what carbon and nitrogen cannot. When the carbon and nitrogen stable isotope data show strong evidence for crustal sources for diamondformation, helium isotopes reveal an unambiguos mantle component hidden within strongly 13C-depleted diamond.
DS202005-0749
2019
Abernethy, F.A.J.Mikhail, S., Crosby, J.C., Stuart, F.M., DiNicola, L., Abernethy, F.A.J.A secretive mechanical exchange between mantle and crustal volatiles revealed by helium isoptopes in 13 C depleted diamonds.Geochemical Perspectives Letters, Vol. 11, pp. 39-43. pdfAfrica, Botswana, South America, French Guianadeposit - Dachine, Orapa

Abstract: Fluid inclusions trapped in fast-growing diamonds provide a unique opportunity to examine the origin of diamonds, and the conditions under which they formed. Eclogitic to websteritic diamondites from southern Africa show 13C-depletion and 15N-enrichment relative to mantle values (?13C = -4.3 to -22.2 ‰ and ?15N = -4.9 to +23.2 ‰). In contrast the 3He/4He of the trapped fluids have a strong mantle signature, one sample has the highest value so far recorded for African diamonds (8.5 ± 0.4 Ra). We find no evidence for deep mantle He in these diamondites, or indeed in any diamonds from southern Africa. A correlation between 3He/4He ratios and 3He concentration suggests that the low 3He/4He are largely the result of ingrowth of radiogenic 4He in the trapped fluids since diamond formation. The He-C-N isotope systematics can be best described by mixing between fluid released from subducted altered oceanic crust and mantle volatiles. The high 3He/4He of low ?13C diamondites reflects the high 3He concentration in the mantle fluids relative to the slab-derived fluids. The presence of post-crystallisation 4He in the fluids means that all 3He/4He are minima, which in turn implies that the slab-derived carbon has a sedimentary organic origin. In short, although carbon and nitrogen stable isotope data show strong evidence for crustal sources for diamond-formation, helium isotopes reveal an unambiguous mantle component hidden within a strongly 13C-depleted system.
DS1999-0625
1999
Abers, G.A.Sarker, G., Abers, G.A.Lithospheric temperature estimates from seismic attentuation across range fronts in southern and central.Geology, Vol. 27, No. 5, May pp. 427-30.GlobalCraton, Tian Shan Mountains
DS200512-0001
2005
Abers, G.A.Abers, G.A.Seismic low velocity layer at the top of subducting slabs: observations, predictions, and systematics.Physics of the Earth and Planetary Interiors, Vol. 149, 1-2, March 15, pp. 7-29.MantleSubduction
DS200612-1402
2006
Abers, G.A.Syracuse, E.M., Abers, G.A.Global compilation of variations in slab depth beneath arc volcanoes and implications.Geochemical, Geophysics, Geosystems: G3, Vol. 7, 5, May 23, 18p.MantleSlab geometry, thickness, dip - not specific to diamond
DS201112-1076
2011
Abers, G.A.Van Keken, P.E., Hacker, B.R., Syracuse, E.M.,Abers, G.A.Subduction factory: 4. Depth dependent flux of H2O from subducting slabs worldwide.Journal of Geophysical Research, Vol. 116, B01401.MantleSubduction
DS201212-0277
2012
Abers, G.A.Hacker, B.R., Abers, G.A.Subduction factory 5: Unusually low Poisson's ratios in subduction zones from elastic anisotropy of peridotite.Journal of Geophysical Research, Vol. 117, B6, B06308.MantleSubduction
DS201707-1298
2017
Abers, G.A.Abers, G.A., van Keken, P.E., Hacker, B.R.The cold and relatively dry nature of mantle forearcs in subduction zones.Nature Geoscience, Vol. 10, pp. 333-337.Mantlesubduction

Abstract: Some of Earth's coldest mantle is found in subduction zones at the tip of the mantle wedge that lies between the subducting and overriding plates. This forearc mantle is isolated from the flow of hot material beneath the volcanic arc, and so is inferred to reach temperatures no more than 600 to 800 °C - conditions at which hydrous mantle minerals should be stable. The forearc mantle could therefore constitute a significant reservoir for water if sufficient water is released from the subducting slab into the mantle wedge. Such a reservoir could hydrate the plate interface and has been invoked to aid the genesis of megathrust earthquakes and slow slip events. Our synthesis of results from thermal models that simulate the conditions for subduction zones globally, however, indicates that dehydration of subducting plates is too slow over the life span of a typical subduction zone to hydrate the forearc mantle. Hot subduction zones, where slabs dehydrate rapidly, are an exception. The hottest, most buoyant forearcs are most likely to survive plate collisions and be exhumed to the surface, so probably dominate the metamorphic rock record. Analysis of global seismic data confirms the generally dry nature of mantle forearcs. We conclude that many subduction zones probably liberate insufficient water to hydrate the shallower plate boundary where great earthquakes and slow slip events nucleate. Thus, we suggest that it is solid-state processes and not hydration that leads to weakening of the plate interface in cold subduction zones.
DS201912-2832
2019
Abers, G.A.van Keken, P.E., Wada, I., Sime, N., Abers, G.A.Thermal structure of the forearc in subduction zones: a comparison of methodologies.Geochemistry, Geophysics, Geosystems, Vol. 20, pp. 3268-3288.Mantlesubduction

Abstract: Molnar and England (1990, https://doi.org/10.1029/JB095iB04p04833) introduced equations using a semianalytical approach that approximate the thermal structure of the forearc regions in subduction zones. A detailed new comparison with high?resolution finite element models shows that the original equations provide robust predictions and can be improved by a few modifications that follow from the theoretical derivation. The updated approximate equations are shown to be quite accurate for a straight?dipping slab that is warmed by heat flowing from its base and by shear heating at its top. The approximation of radiogenic heating in the crust of the overriding plate is less accurate but the overall effect of this heating mode is small. It is shown that the previous and updated approximate equations become increasingly inaccurate with decreasing thermal parameter and increasing variability of slab dip. It is also shown that the approximate equations cannot be extrapolated accurately past the brittle?ductile transition. Conclusions in a recent paper (Kohn et al., 2018, https://doi.org/10.1073/pnas.1809962115) that modest amount of shear heating can explain the thermal conditions of past subduction from the exhumed metamorphic rock record are invalid due to a number of compounding errors in the application of the Molnar and England (1990, https://doi.org/10.1029/JB095iB04p04833) equations past the brittle?ductile transition. The use of the improved approximate equations is highly recommended provided their limitations are taken into account. For subduction zones with variable dip and/or low thermal parameter finite element modeling is recommended.
DS200412-1914
2004
Abers, G.C.Stachnik, J.C., Abers, G.C., Christensen, D.H.Seismic attenuation and mantle wedge temperatures in the Alaska subduction zone.Journal of Geophysical Research, Vol. 109, B10, B10405 10.1029/2004 JBO3018United States, AlaskaGeophysics - seismics, geothermometry
DS201610-1838
2016
Abersteiner, A.Abersteiner, A., Giuliani, A., Kamenetsky, V.S., Phillips, D.Petrographic and melt inclusion constraints on the petrogenesis of a magmaclast from the Venetia kimberlite cluster, South Africa.Chemical Geology, in press available 11p.Africa, South AfricaDeposit - Venetia

Abstract: Kimberlitic magmaclasts are discrete ovoid magmatic fragments that formed prior to emplacement from disrupted kimberlite magma. To provide new constraints on the origin and evolution of the kimberlite melts, we document the mineralogy and petrography of a magmaclast recovered from one of the ca. 520 Ma Venetia kimberlites, South Africa. The sample (BI9883) has a sub-spherical shape and consists of a ~ 10 mm diameter central olivine macrocryst, surrounded by porphyritic kimberlite. The kimberlitic material consists of concentrically aligned, altered olivine phenocrysts, set in a crystalline groundmass of calcite, chromite, perovskite, phlogopite, apatite, ilmenite, titanite, sulphides, rutile and magnetite along with abundant alteration phases (i.e. serpentine, talc and secondary calcite). These features are typical of archetypal hypabyssal kimberlites. We examined primary fluid/melt inclusions in chromite, perovskite and apatite containing a diversity of daughter phases. Chromite and perovskite host polycrystalline inclusions containing abundant alkali-carbonates (i.e. enriched in K, Na, Ba, Sr), phosphates, Na-K chlorides, sulphides and equal to lesser quantities of olivine, phlogopite and pleonaste. In contrast, apatite hosts polycrystalline assemblages with abundant alkali-carbonates and Na-K chlorides and lesser amounts of olivine, monticellite and phlogopite. Numerous solid inclusions of shortite (Na2Ca2(CO3)3), Na-Sr-carbonates and apatite occur in groundmass calcite along with fluid inclusions containing daughter crystals of Na-carbonates and Na-chlorides. The primary inclusions in chromite, perovskite and apatite are considered to represent remnants of fluid(s)/melt(s) trapped during crystallisation of the host minerals, whereas the fluid inclusions in calcite are probably secondary in origin. The component proportions of these primary fluid/melt inclusions were estimated in an effort to constrain the composition of the evolving kimberlite melt. These estimates suggest melt evolution from a silicate-carbonate kimberlite melt that became increasingly enriched in carbonates, phosphates, alkalis and chlorides, in response to the fractional crystallisation of constituent minerals (i.e. olivine to apatite). The concentric alignment of crystals around the olivine kernel and ovoid shape of the magmaclast can be ascribed to the low viscosity of the kimberlite melt and rapid rotation whilst in a liquid or partial crystalline state, or to progressive layer-by-layer growth of the magmaclast. Although the mineralogy of our sample is similar to hypabyssal kimberlites worldwide, it differs from hypabyssal kimberlite units in the main Venetia pipes, which contain monticellite-phlogopite rich assemblages and segregationary matrix textures. Therefore magmaclast BI9883 probably originated from a batch of magma distinct from those that produced known hypabyssal units within the Venetia kimberlite cluster.-
DS201707-1299
2017
Abersteiner, A.Abersteiner, A., Giuliani, A., Kamenetsky, V.S., Phillips, D.Petrographic and melt inclusion constraints on the petrogenesis of a magmaclast from the Venetia kimberlite cluster, South Africa.Chemical Geology, Vol. 455, pp. 331-341.Africa, South Africadeposit - Venetia

Abstract: Kimberlitic magmaclasts are discrete ovoid magmatic fragments that formed prior to emplacement from disrupted kimberlite magma. To provide new constraints on the origin and evolution of the kimberlite melts, we document the mineralogy and petrography of a magmaclast recovered from one of the ca. 520 Ma Venetia kimberlites, South Africa. The sample (BI9883) has a sub-spherical shape and consists of a ~ 10 mm diameter central olivine macrocryst, surrounded by porphyritic kimberlite. The kimberlitic material consists of concentrically aligned, altered olivine phenocrysts, set in a crystalline groundmass of calcite, chromite, perovskite, phlogopite, apatite, ilmenite, titanite, sulphides, rutile and magnetite along with abundant alteration phases (i.e. serpentine, talc and secondary calcite). These features are typical of archetypal hypabyssal kimberlites. We examined primary fluid/melt inclusions in chromite, perovskite and apatite containing a diversity of daughter phases. Chromite and perovskite host polycrystalline inclusions containing abundant alkali-carbonates (i.e. enriched in K, Na, Ba, Sr), phosphates, Na-K chlorides, sulphides and equal to lesser quantities of olivine, phlogopite and pleonaste. In contrast, apatite hosts polycrystalline assemblages with abundant alkali-carbonates and Na-K chlorides and lesser amounts of olivine, monticellite and phlogopite. Numerous solid inclusions of shortite (Na2Ca2(CO3)3), Na-Sr-carbonates and apatite occur in groundmass calcite along with fluid inclusions containing daughter crystals of Na-carbonates and Na-chlorides. The primary inclusions in chromite, perovskite and apatite are considered to represent remnants of fluid(s)/melt(s) trapped during crystallisation of the host minerals, whereas the fluid inclusions in calcite are probably secondary in origin. The component proportions of these primary fluid/melt inclusions were estimated in an effort to constrain the composition of the evolving kimberlite melt. These estimates suggest melt evolution from a silicate-carbonate kimberlite melt that became increasingly enriched in carbonates, phosphates, alkalis and chlorides, in response to the fractional crystallisation of constituent minerals (i.e. olivine to apatite). The concentric alignment of crystals around the olivine kernel and ovoid shape of the magmaclast can be ascribed to the low viscosity of the kimberlite melt and rapid rotation whilst in a liquid or partial crystalline state, or to progressive layer-by-layer growth of the magmaclast. Although the mineralogy of our sample is similar to hypabyssal kimberlites worldwide, it differs from hypabyssal kimberlite units in the main Venetia pipes, which contain monticellite-phlogopite rich assemblages and segregationary matrix textures. Therefore magmaclast BI9883 probably originated from a batch of magma distinct from those that produced known hypabyssal units within the Venetia kimberlite cluster.
DS201708-1563
2017
Abersteiner, A.Abersteiner, A., Kamanetsky, V.S., Kamenetsky, M., Goemann, K., Ehrig, K., Rodemann, T.Significance of halogens ( F, Cl) in kimberlite melts: insights from mineralogy and melt inclusions in the Roger pipe ( Ekati, Canada).Chemical Geology, in press available, 16p.Canada, Northwest Territoriesdeposit, Roger, Ekati

Abstract: The abundance and distribution of halogens (F, Cl) are rarely recorded in kimberlites and therefore their petrogenetic significance is poorly constrained. Halogens are usually present in kimberlite rocks in the structure of phlogopite and apatite, but their original concentrations are never fully retained due to the effects of alteration. To provide new constraints on the origin and evolution of halogens in kimberlites and their melts, we present a detailed study of the petrography and geochemistry of the late-Cretaceous Group-I (or archetypal) Roger kimberlite (Ekati cluster, Canada). The studied samples contain abundant anhedral-to-euhedral olivine which is set in a crystalline groundmass of monticellite, phlogopite, apatite, spinel (i.e. magnesian ulvöspinel-magnetite (MUM), Mg-magnetite, pleonaste, Cr-spinel), and perovskite along with abundant secondary alteration phases (i.e. serpentine, garnet (andradite-schlorlomite), amakinite ((Fe2 +, Mg, Mn)(OH)2), calcite). The Roger kimberlite is characterised by the highest recorded F-content (up to 2688 ppm) of the Ekati cluster kimberlites, which is reflected by the preservation of F-rich phases, where bultfonteinite (Ca4(Si2O7)(F, OH)2) and fluorite commonly replace olivine. In order to examine the composition and evolution of the kimberlite melt prior to post-magmatic processes, we studied melt inclusions in olivine, Cr-spinel, monticellite and apatite. Primary multiphase melt inclusions in Cr-spinel, monticellite and apatite and secondary inclusions in olivine are shown to contain a diversity of daughter phases and compositions that are dominated by alkali/alkali-earth (Na, K, Ba, Sr)-enriched Ca-Mg-carbonates ± F, Na-K-chlorides and sulphates, phosphates ± REE, spinel, silicates (e.g. olivine, phlogopite, (clino)humite), and sulphides. Although alkali/alkali-earth- and halogen-bearing phases are abundant in melt inclusions, they are generally absent from the kimberlite groundmass, most likely due to ubiquitous effects of syn- and/or post-magmatic alteration (i.e. serpentinisation). Comparisons between halogens and other trace elements of similar compatibility (i.e. F/Nd and Cl/U) in the Roger kimberlite and their respective estimated primitive mantle abundances show that halogens should be a more significant component in kimberlites than typically measured. We propose that fluorine in the Roger kimberlite was magmatic and was redistributed during hydrothermal alteration by Ca-bearing serpentinising fluids to produce the observed bultfonteinite/fluorite assemblages. Based the compositions and daughter mineral assemblages in primary melt inclusions and reconstructed halogen abundances, we suggest that Cr-spinel, monticellite and apatite crystallised from a variably differentiated Si-P-Cl-F-bearing carbonate melt that was enriched in alkalis/alkali-earths and highly incompatible trace elements
DS201708-1564
2017
Abersteiner, A.Abersteiner, A., Kamanetsky, V.S., Pearson, D.G., Kamenetsky, M., Ehrig, K., Goemann, K., Rodemann, T.Monticellite in group I kimberlites: implications for evolution of parallel melts and post emplacement CO2 degassing. Leslie, Pipe 1Chemical Geology, in press available, 54p.Canada, Northwest Territories, Europe, Finlanddeposit, Leslie

Abstract: Monticellite is a magmatic and/or deuteric mineral that is often present, but widely varying in concentrations in Group-I (or archetypal) kimberlites. To provide new constraints on the petrogenesis of monticellite and its potential significance to kimberlite melt evolution, we examine the petrography and geochemistry of the minimally altered hypabyssal monticellite-rich Leslie (Canada) and Pipe 1 (Finland) kimberlites. In these kimberlites, monticellite (Mtc) is abundant (25–45 vol%) and can be classified into two distinct morphological types: discrete and intergrown groundmass grains (Mtc-I), and replacement of olivine (Mtc-II). Monticellite in group-I kimberlites: Implications for evolution of parental melts and post-emplacement CO 2 degassing (PDF Download Available).
DS201708-1588
2017
Abersteiner, A.Abersteiner, A.Significance of halogens ( F, Cl) in kimberlite melts: insights from mineralogy and melt inclusions in the Roger pipe ( Ekati, Canada).11th. International Kimberlite Conference, PosterCanada, Northwest Territoriesdeposit - Roger

Abstract: The abundance and distribution of halogens (F, Cl) are rarely recorded in kimberlites and therefore their petrogenetic significance is poorly constrained. Halogens are usually present in kimberlite rocks in the structure of phlogopite and apatite, but their original concentrations are never fully retained due to the effects of alteration. To provide new constraints on the origin and evolution of halogens in kimberlites and their melts, we present a detailed study of the petrography and geochemistry of the late-Cretaceous Group-I (or archetypal) Roger kimberlite (Ekati cluster, Canada). The studied samples contain abundant anhedral-to-euhedral olivine which is set in a crystalline groundmass of monticellite, phlogopite, apatite, spinel (i.e. magnesian ulvöspinel-magnetite (MUM), Mg-magnetite, pleonaste, Cr-spinel), and perovskite along with abundant secondary alteration phases (i.e. serpentine, garnet (andradite-schlorlomite), amakinite ((Fe2 +, Mg, Mn)(OH)2), calcite). The Roger kimberlite is characterised by the highest recorded F-content (up to 2688 ppm) of the Ekati cluster kimberlites, which is reflected by the preservation of F-rich phases, where bultfonteinite (Ca4(Si2O7)(F, OH)2) and fluorite commonly replace olivine. In order to examine the composition and evolution of the kimberlite melt prior to post-magmatic processes, we studied melt inclusions in olivine, Cr-spinel, monticellite and apatite. Primary multiphase melt inclusions in Cr-spinel, monticellite and apatite and secondary inclusions in olivine are shown to contain a diversity of daughter phases and compositions that are dominated by alkali/alkali-earth (Na, K, Ba, Sr)-enriched Ca-Mg-carbonates ± F, Na-K-chlorides and sulphates, phosphates ± REE, spinel, silicates (e.g. olivine, phlogopite, (clino)humite), and sulphides. Although alkali/alkali-earth- and halogen-bearing phases are abundant in melt inclusions, they are generally absent from the kimberlite groundmass, most likely due to ubiquitous effects of syn- and/or post-magmatic alteration (i.e. serpentinisation). Comparisons between halogens and other trace elements of similar compatibility (i.e. F/Nd and Cl/U) in the Roger kimberlite and their respective estimated primitive mantle abundances show that halogens should be a more significant component in kimberlites than typically measured. We propose that fluorine in the Roger kimberlite was magmatic and was redistributed during hydrothermal alteration by Ca-bearing serpentinising fluids to produce the observed bultfonteinite/fluorite assemblages. Based the compositions and daughter mineral assemblages in primary melt inclusions and reconstructed halogen abundances, we suggest that Cr-spinel, monticellite and apatite crystallised from a variably differentiated Si-P-Cl-F-bearing carbonate melt that was enriched in alkalis/alkali-earths and highly incompatible trace elements.
DS201708-1589
2017
Abersteiner, A.Abersteiner, A.Monticellite in Group 1 kimberlites: implications for evolution of partial melts and post-emplacement CO2 degassing.11th. International Kimberlite Conference, PosterTechnologymonticellite

Abstract: Monticellite is a magmatic and/or deuteric mineral that is often present, but widely varying in concentrations in Group-I (or archetypal) kimberlites. To provide new constraints on the petrogenesis of monticellite and its potential significance to kimberlite melt evolution, we examine the petrography and geochemistry of the minimally altered hypabyssal monticellite-rich Leslie (Canada) and Pipe 1 (Finland) kimberlites. In these kimberlites, monticellite (Mtc) is abundant (25–45 vol%) and can be classified into two distinct morphological types: discrete and intergrown groundmass grains (Mtc-I), and replacement of olivine (Mtc-II). Monticellite in group-I kimberlites: Implications for evolution of parental melts and post-emplacement CO 2 degassing (PDF Download Available). Available from: https://www.researchgate.net/publication/318032868_Monticellite_in_group-I_kimberlites_Implications_for_evolution_of_parental_melts_and_post-emplacement_CO_2_degassing [accessed Aug 10, 2017].
DS201711-2522
2017
Abersteiner, A.Kargin, A.V., Sazonova, L.V., Nosova, A.A., Lebedeva, N.M., Tretyachenko, V.V., Abersteiner, A.Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts.Lithos, in press available, 52p.Russia, Archangeldeposit - Grib

Abstract: To provide new insights into the origin of megacrysts and metasomatism of the subcontinental lithospheric mantle (SCLM), we present a detailed petrographic and geochemical investigation of clinopyroxene-phlogopite xenoliths and clinopyroxene megacrysts from the Grib kimberlite (Arkhangelsk diamond province, Russia). Clinopyroxene megacrysts and clinopyroxene from clinopyroxene-phlogopite xenoliths have similar petrography, major and trace element compositions, and are therefore classified as Cr-rich megacrysts. Geothermobarometry suggests that Cr-rich clinopyroxenes originate from within the SCLM (3.6-4.7 GPa and 764-922 °C). Phlogopite from clinopyroxene-phlogopite xenoliths have low-Ti and -Cr compositions that overlaps with phlogopite megacrysts from the Grib kimberlite. The clinopyroxene-phlogopite rocks within the SCLM are the main source for Cr-rich clinopyroxene and low-Ti phlogopite megacrysts in the Grib kimberlite matrix. Trace element compositions of studied Cr-rich clinopyroxenes have similar geochemical features to clinopyroxenes megacrysts occurrences worldwide and overlap with clinopyroxenes from phlogopite-garnet peridotite xenoliths from the Grib kimberlite. The strong depletion in Ti, Nb, Ta and to a lesser extent in Zr and Hf in clinopyroxene reflects equilibrium with Ti-oxides, such as ilmenite. The clinopyroxene-phlogopite xenoliths could be the final product of metasomatism of garnet peridotites within the SCLM beneath the Grib kimberlite. The calculated equilibrium of clinopyroxene melt compositions suggests that the metasomatic agents were derived from silicate-bearing kimberlite melts. The presence of veinlets infilled with kimberlitic mineral assemblages in clinopyroxene grains suggests that the clinopyroxene-phlogopite rocks experienced intense interactions with kimberlite melt after their formation, but before their entrainment into the host kimberlite magma. This interaction resulted in the formation of high-Ti and -Cr phlogopite and high-Ti clinopyroxene rims, zones and grains with spongy textures. Finally, we propose the sequence of metasomatic events that occurred in the SCLM and the subsequent formation of the Grib kimberlite.
DS201802-0216
2018
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Kamenetsky, M., Goemann, K., Ehrig, K., Rodemann, T.Significance of halogens ( F, Cl) in kimberlite melts: insights from mineralogy and melt inclusions in the Roger pipe ( Ekati, Canada).Chemical Geology, Vol. 478, pp. 148-163.Canada, Northwest Territoriesdeposit - Roger

Abstract: The abundance and distribution of halogens (F, Cl) are rarely recorded in kimberlites and therefore their petrogenetic significance is poorly constrained. Halogens are usually present in kimberlite rocks in the structure of phlogopite and apatite, but their original concentrations are never fully retained due to the effects of alteration. To provide new constraints on the origin and evolution of halogens in kimberlites and their melts, we present a detailed study of the petrography and geochemistry of the late-Cretaceous Group-I (or archetypal) Roger kimberlite (Ekati cluster, Canada). The studied samples contain abundant anhedral-to-euhedral olivine which is set in a crystalline groundmass of monticellite, phlogopite, apatite, spinel (i.e. magnesian ulvöspinel-magnetite (MUM), Mg-magnetite, pleonaste, Cr-spinel), and perovskite along with abundant secondary alteration phases (i.e. serpentine, garnet (andradite-schlorlomite), amakinite ((Fe2 +, Mg, Mn)(OH)2), calcite). The Roger kimberlite is characterised by the highest recorded F-content (up to 2688 ppm) of the Ekati cluster kimberlites, which is reflected by the preservation of F-rich phases, where bultfonteinite (Ca4(Si2O7)(F, OH)2) and fluorite commonly replace olivine. In order to examine the composition and evolution of the kimberlite melt prior to post-magmatic processes, we studied melt inclusions in olivine, Cr-spinel, monticellite and apatite. Primary multiphase melt inclusions in Cr-spinel, monticellite and apatite and secondary inclusions in olivine are shown to contain a diversity of daughter phases and compositions that are dominated by alkali/alkali-earth (Na, K, Ba, Sr)-enriched Ca-Mg-carbonates ± F, Na-K-chlorides and sulphates, phosphates ± REE, spinel, silicates (e.g. olivine, phlogopite, (clino)humite), and sulphides. Although alkali/alkali-earth- and halogen-bearing phases are abundant in melt inclusions, they are generally absent from the kimberlite groundmass, most likely due to ubiquitous effects of syn- and/or post-magmatic alteration (i.e. serpentinisation). Comparisons between halogens and other trace elements of similar compatibility (i.e. F/Nd and Cl/U) in the Roger kimberlite and their respective estimated primitive mantle abundances show that halogens should be a more significant component in kimberlites than typically measured. We propose that fluorine in the Roger kimberlite was magmatic and was redistributed during hydrothermal alteration by Ca-bearing serpentinising fluids to produce the observed bultfonteinite/fluorite assemblages. Based the compositions and daughter mineral assemblages in primary melt inclusions and reconstructed halogen abundances, we suggest that Cr-spinel, monticellite and apatite crystallised from a variably differentiated Si-P-Cl-F-bearing carbonate melt that was enriched in alkalis/alkali-earths and highly incompatible trace elements.
DS201802-0217
2018
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Pearson, D.G., Kamenetsky, M., Goemann, K., Ehrig, K., Rodemann, T.Monticellite in group I kimberlites: implications for evolution of parental melts and post emplacement CO2 degassing.Chemical Geology, Vol. 478, pp. 76-88.Canada, Northwest Territories, Europe, Finlanddeposit - Leslie, Pipe 1

Abstract: Monticellite is a magmatic and/or deuteric mineral that is often present, but widely varying in concentrations in Group-I (or archetypal) kimberlites. To provide new constraints on the petrogenesis of monticellite and its potential significance to kimberlite melt evolution, we examine the petrography and geochemistry of the minimally altered hypabyssal monticellite-rich Leslie (Canada) and Pipe 1 (Finland) kimberlites. In these kimberlites, monticellite (Mtc) is abundant (25-45 vol%) and can be classified into two distinct morphological types: discrete and intergrown groundmass grains (Mtc-I), and replacement of olivine (Mtc-II). Primary multiphase melt inclusions in monticellite, perovskite and Mg-magnetite contain assemblages dominated by alkali (Na, K, Ba, Sr)-enriched Ca-Mg-carbonates, chlorides, phosphates, spinel, silicates (e.g. olivine, phlogopite) and sulphides. These melt inclusions probably represent snapshots of a variably differentiated kimberlite melt that evolved in-situ towards carbonatitic and silica-poor compositions. Although unconstrained in their concentration, the presence of alkali-carbonates and chlorides in melt inclusions suggests they are a more significant component of the kimberlite melt than commonly recorded by whole-rock analyses. We present petrographic and textural evidence showing that pseudomorphic Mtc-II resulted from an in-situ reaction between olivine and the carbonate component of the kimberlite melt in the decarbonation reactio. This reaction is supported by the preservation of abundant primary inclusions of periclase and to a lesser extent Fe-Mg-oxides in monticellite, perovskite and Mg-magnetite. Based on the preservation of primary periclase inclusions, we infer that periclase also existed in the groundmass, but was subsequently altered to brucite. We suggest that CO2 degassing in the latter stages of kimberlite emplacement into the crust is largely driven by the observed reaction between olivine and the carbonate melt. For this reaction to proceed, CO2 should be removed (i.e. degassed), which will cause further reaction and additional degassing in response to this chemical system change (Le Chatelier's principle). Our study demonstrates that these proposed decarbonation reactions may be a commonly overlooked process in the crystallisation of monticellite and exsolution of CO2, which may in turn contribute to the explosive eruption and brecciation processes that occur during kimberlite magma emplacement and pipe formation.
DS201811-2552
2018
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Golovin, A.V., Kamenetsky, M., Goemann, K.Was crustal contamination involved in the formation of the serpentine-free Udachnaya-East kimberlite? New insights into parental melts, liquids, liquidus assemblage and effects of alteration.Journal of Petrology, Vol. 59, 8, pp. 1467-1492.Russiadeposit - Udachnaya-East

Abstract: The petrologically unique Udachnaya-East kimberlite (Siberia, Russia) is characterised by unserpentinised and H2O-poor volcaniclastic and coherent units that contain fresh olivine, along with abundant alkali-rich carbonates, chlorides, sulphides and sulphates in the groundmass. These mineralogical and geochemical characteristics have led to two divergent models that advocate different origins. It has been suggested that the unserpentinised units from Udachnaya-East are representative of pristine unaltered kimberlite. Conversely, the alkali-chlorine-sulphur enrichment has been attributed to interactions with crustal materials and/or post-emplacement contamination by brines. The mineralogical and geochemical features and the compositions of melt inclusions in unserpentinised and serpentinised Udachnaya-East kimberlite varieties are compared in this study. Both varieties of kimberlite have similar major, compatible and incompatible trace element concentrations and primitive mantle normalised trace element patterns, groundmass textures and silicate, oxide and sulphide mineral compositions. However, these two kimberlite varieties are distinguished by: (i) the presence of unaltered olivine, abundant Na-K-Cl-S-rich minerals (i.e. chlorides, S-bearing alkali-carbonates, sodalite) and the absence of H2O-rich phases (i.e. serpentine, iowaite (Mg4Fe3+(OH)8OCl•3(H2O)) in unserpentinised samples, and (ii) the absence of alkali- and chlorine-enriched phases in the groundmass and characteristic olivine alteration (i.e. replacement by serpentine and/or iowaite) in serpentinised samples. In addition, melt inclusions hosted in olivine, monticellite, spinel and perovskite from unserpentinised and serpentinised kimberlite contain identical daughter phase assemblages that are dominated by alkali-carbonates, chlorides and sulphates/sulphides. This enrichment in alkalis, chlorine and sulphur in melt inclusions demonstrates that these elements were an intrinsic part of the parental magma. The paucity of alkali-carbonates and chlorides in the groundmass of serpentinised Udachnaya-East kimberlite is attributed to their instability and removal during post-emplacement alteration. All evidence previously used in support of crustal and brine contamination of the Udachnaya-East kimberlite is thoroughly evaluated. We demonstrate that ‘contamination models’ are inconsistent with petrographic, geochemical and melt inclusion data. Our combined data suggest that the Udachnaya-East kimberlite crystallised from an essentially H2O-poor, Si-Na-K-Cl-S-bearing carbonate-rich melt.
DS201812-2771
2018
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Giuliani, A., Howarth, G.H., Castillo-Oliver, M., Thomspon, J., Kamenetsky,M., Cherry, A.Composition and emplacement of the Benfontein kimberlite sill complex ( Kimberley, South Africa): textural, petrographic and melt inclusion constraints.Lithos, doi.org/10.1016 /jlithos.2018 .11.017 32p.Africa, South Africadeposit - Benfontein

Abstract: The Benfontein kimberlite is a renowned example of a sill complex and provides an excellent opportunity to examine the emplacement and evolution of intrusive kimberlite magmas. We have undertaken a detailed petrographic and melt inclusion study of the Benfontein Upper, Middle and Lower sills. These sills range in thickness from 0.25 to 5?m. New perovskite and baddeleyite U/Pb dating produced ages of 85.7?±?4.4?Ma and 86.5?±?2.6?Ma, respectively, which are consistent with previous age determinations and indicate emplacement coeval with other kimberlites of the Kimberley cluster. The Benfontein sills are characterised by large variations in texture (e.g., layering) and mineral modal abundance between different sill levels and within individual samples. The Lower Sill is characterised by carbonate-rich diapirs, which intrude into oxide-rich layers from underlying carbonate-rich levels. The general paucity of xenogenic mantle material in the Benfontein sills is attributed to its separation from the host magma during flow differentiation during lateral spreading. The low viscosity is likely responsible for non-explosive emplacement of the Benfontein sills, while the rhythmic layering is attributed to multiple magma injections. The Benfontein sills are marked by the excellent preservation of olivine and groundmass mineralogy, which is composed of monticellite, spinel, perovskite, baddeleyite, ilmenite, apatite, calcite, dolomite along with secondary serpentine and glagolevite [NaMg6[Si3AlO10](OH,O)8•H2O]. This is the first time glagolevite is reported in kimberlites. Groundmass spinel exhibits atoll-textures and is composed of a magnesian ulvöspinel magnetite (MUM) or chromite core, surrounded by occasional pleonaste and a rim of Mg-Al-magnetite. We suggest that pleonaste crystallised as a magmatic phase, but was resorbed back into the residual host melt and/or removed by alteration. Analyses of secondary inclusions in olivine and primary inclusions in monticellite, spinel, perovskite, apatite and interstitial calcite are largely composed of Ca-Mg carbonates and, to a lesser extent, alkali-carbonates and other phases. These inclusions probably represent the entrapment of variably differentiated parental kimberlite melts, which became progressively more enriched in carbonate, alkalis, halogens and sulphur during crystal fractionation. Carbonate-rich diapirs from the Lower Sill contain more exotic phase assemblages (e.g., Ba-Fe titanate, barite, ancylite, pyrochlore), which probably result from the extreme differentiation of residual kimberlite melts followed by physical separation and isolation from the parental carbonate-rich magma. It is likely that any alkali or halogen rich minerals crystallising in the groundmass were removed from the groundmass during syn?/post-magmatic alteration, or in the case of Na, remobilised to form secondary glagolevite. The Benfontein sill complex therefore provides a unique example of how the composition of kimberlites may be modified after magma emplacement in the upper crust.
DS201902-0254
2019
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Giuliani, A., Howarth, G.H., Castillo-Oliver, M., Thompson, J., Kamenetsky, M., Cherry, A.Composition and emplacement of the Benfontein kimberlite sill complex ( Kimberley, South Africa): textural, petrographic and melt inclusion constraints.Lithos, Vol. 324-325, pp. 297-314.Africa, South Africadeposit - Benfontein

Abstract: The Benfontein kimberlite is a renowned example of a sill complex and provides an excellent opportunity to examine the emplacement and evolution of intrusive kimberlite magmas. We have undertaken a detailed petrographic and melt inclusion study of the Benfontein Upper, Middle and Lower sills. These sills range in thickness from 0.25 to 5?m. New perovskite and baddeleyite U/Pb dating produced ages of 85.7?±?4.4?Ma and 86.5?±?2.6?Ma, respectively, which are consistent with previous age determinations and indicate emplacement coeval with other kimberlites of the Kimberley cluster. The Benfontein sills are characterised by large variations in texture (e.g., layering) and mineral modal abundance between different sill levels and within individual samples. The Lower Sill is characterised by carbonate-rich diapirs, which intrude into oxide-rich layers from underlying carbonate-rich levels. The general paucity of xenogenic mantle material in the Benfontein sills is attributed to its separation from the host magma during flow differentiation during lateral spreading. The low viscosity is likely responsible for non-explosive emplacement of the Benfontein sills, while the rhythmic layering is attributed to multiple magma injections. The Benfontein sills are marked by the excellent preservation of olivine and groundmass mineralogy, which is composed of monticellite, spinel, perovskite, baddeleyite, ilmenite, apatite, calcite, dolomite along with secondary serpentine and glagolevite [NaMg6[Si3AlO10](OH,O)8•H2O]. This is the first time glagolevite is reported in kimberlites. Groundmass spinel exhibits atoll-textures and is composed of a magnesian ulvöspinel - magnetite (MUM) or chromite core, surrounded by occasional pleonaste and a rim of Mg-Al-magnetite. We suggest that pleonaste crystallised as a magmatic phase, but was resorbed back into the residual host melt and/or removed by alteration. Analyses of secondary inclusions in olivine and primary inclusions in monticellite, spinel, perovskite, apatite and interstitial calcite are largely composed of Ca-Mg carbonates and, to a lesser extent, alkali-carbonates and other phases. These inclusions probably represent the entrapment of variably differentiated parental kimberlite melts, which became progressively more enriched in carbonate, alkalis, halogens and sulphur during crystal fractionation. Carbonate-rich diapirs from the Lower Sill contain more exotic phase assemblages (e.g., Ba-Fe titanate, barite, ancylite, pyrochlore), which probably result from the extreme differentiation of residual kimberlite melts followed by physical separation and isolation from the parental carbonate-rich magma. It is likely that any alkali or halogen rich minerals crystallising in the groundmass were removed from the groundmass during syn?/post-magmatic alteration, or in the case of Na, remobilised to form secondary glagolevite. The Benfontein sill complex therefore provides a unique example of how the composition of kimberlites may be modified after magma emplacement in the upper crust.
DS201902-0255
2019
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Golovin, A.V., Sharygin, I.S., Giuliani, A., Rodemann, T., Spetsius, Z.V., Kamenetsky, M.Djerfisherite in kimberlites and their xenoliths: implications for kimberlite melt evolution.Contributions to Mineralogy and Petrology, Vol. 174, 8 22p. Africa, South Africa, Russia, Canada, Northwest Territoriesdeposit - Bultfontein, Roberts Victor, Udachnaya-East, Obnazhennaya, Vtorogodnitsa, Koala, Leslie

Abstract: Djerfisherite (K6(Fe,Ni,Cu)25S26Cl) occurs as an accessory phase in the groundmass of many kimberlites, kimberlite-hosted mantle xenoliths, and as a daughter inclusion phase in diamonds and kimberlitic minerals. Djerfisherite typically occurs as replacement of pre-existing Fe-Ni-Cu sulphides (i.e. pyrrhotite, pentlandite and chalcopyrite), but can also occur as individual grains, or as poikilitic phase in the groundmass of kimberlites. In this study, we present new constraints on the origin and genesis of djerfisherite in kimberlites and their entrained xenoliths. Djerfisherite has extremely heterogeneous compositions in terms of Fe, Ni and Cu ratios. However, there appears to be no distinct compositional range of djerfisherite indicative of a particular setting (i.e. kimberlites, xenoliths or diamonds), rather this compositional diversity reflects the composition of the host kimberlite melt and/or interacting metasomatic medium. In addition, djerfisherite may contain K and Cl contents less than the ideal formula unit. Raman spectroscopy and electron backscatter diffraction (EBSD) revealed that these K-Cl poor sulphides still maintain the same djerfisherite crystal structure. Two potential mechanisms for djerfisherite formation are considered: (1) replacement of pre-existing Fe-Ni-Cu sulphides by djerfisherite, which is attributed to precursor sulphides reacting with metasomatic K-Cl bearing melts/fluids in the mantle or the transporting kimberlite melt; (2) direct crystallisation of djerfisherite from the kimberlite melt in groundmass or due to kimberlite melt infiltration into xenoliths. The occurrence of djerfisherite in kimberlites and its mantle cargo from localities worldwide provides strong evidence that the metasomatising/infiltrating kimberlite melt/fluid was enriched in K and Cl. We suggest that kimberlites originated from melts that were more enriched in alkalis and halogens relative to their whole-rock compositions.
DS201902-0294
2018
Abersteiner, A.Malyeshev, S.V., Pasenko, A.M., Ivanov, A.V., Gladkochub, D.P., Savatenkov, V.M., Meffre, S., Abersteiner, A., Kamenetsky, V.S., Shcherbakov, V.D.Geodynamic significance of the Mesoproterozoic magmatism of the Udzha paleo-rift ( Northern Siberian craton) based in U-Pb geochronology and paleomagnetic data.Minerals ( mdpi.com), Vol. 8, 12, 11p. PdfRussia, Siberiacraton

Abstract: The emplacement age of the Great Udzha Dyke (northern Siberian Craton) was determined by the U-Pb dating of apatite using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). This produced an age of 1386 ± 30 Ma. This dyke along with two other adjacent intrusions, which cross-cut the sedimentary units of the Udzha paleo-rift, were subjected to paleomagnetic investigation. The paleomagnetic poles for the Udzha paleo-rift intrusions are consistent with previous results published for the Chieress dyke in the Anabar shield of the Siberian Craton (1384 ± 2 Ma). Our results suggest that there was a period of intense volcanism in the northern Siberian Craton, as well as allow us to reconstruct the apparent migration of the Siberian Craton during the Mesoproterozoic.
DS201905-1014
2019
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Golovin, A.V., Gornova, M.A.Polymineralic inclusions in kimberlite hosted megacrysts: implications for kimberlite melt evolution.Lithos, doi.101016/j.lithos .2019.04.004 42p.Canada, Northwest Territories, Russiadeposit - Diavik, Jericho, Leslie, Udachnaya East

Abstract: Megacrysts are large (cm to >20?cm in size) mantle-derived crystals, which are commonly entrained by kimberlite magmas, comprising of olivine, orthopyroxene, clinopyroxene, phlogopite, garnet, ilmenite and zircon as common phases. Numerous studies have shown megacrysts to contain polymineralic inclusions, which have been interpreted to represent entrapped kimberlite melt. To constrain the origin of these inclusions in megacrysts and their relationship to kimberlite magmatism, we present a detailed petrographic and geochemical study of clinopyroxene and olivine megacrysts and their hosted inclusions from the Diavik, Jericho, Leslie (Slave Craton, Canada) and Udachnaya-East (Siberian Craton, Russia) kimberlites. The studied megacrysts are between 1 and 3?cm in size and representative of both the Cr-rich and Cr-poor suites. Megacrysts contain two types of inclusions: i. Large (<0.5-5?mm in size) round-to-irregular shaped polymineralic inclusions, which are composed of minerals similar to the host kimberlite groundmass, and consist of olivine, calcite, spinel, perovskite, phlogopite and apatite (± serpentine, alkali-carbonates, alkali-chlorides, barite). ii. Swarms/trails of ‘micro melt inclusions’ (MMI; <1-5??m in size), which surround polymineralic inclusions, veins and fractures, thereby forming a ‘spongy’ texture. MMIs generally contain multiphase assemblages similar to polymineralic inclusions as well as various additional phases, such as alkali-carbonates or alkali-chlorides, which are typically absent in polymineralic inclusions and the surrounding kimberlite groundmass. Textural and geochemical evidence suggests that polymineralic inclusions in megacrysts crystallised from kimberlite melt, which infiltrated along fracture/vein networks. The polymineralic inclusion assemblages resulted from disequilibria reactions between the host megacryst and infiltrating kimberlite melt, which was likely enhanced by rapidly changing conditions during magmatic ascent. The connectivity of polymineralic inclusions to the kimberlite groundmass via network veins/fractures suggests that they are susceptible to infiltrating post-emplacement fluids. Therefore, the vast majority of polymineralic inclusions are unlikely to represent ‘pristine’ entrapped kimberlite melt. In contrast, MMIs are isolated within megacrysts (i.e. not connected to fractures/veins and therefore shielded from post-magmatic fluids) and probably represent entrapped remnants of the variably differentiated kimberlite melt, which was more enriched in alkalis-Cl-S-CO2 than serpentinised polymineralic inclusions and the host rocks exposed at Earth's surface as kimberlites.
DS201910-2259
2019
Abersteiner, A.Golovin, A.V., Sharygin, I., Korsakov, A.V., Kamenetsky, V.S., Abersteiner, A.Can primitive kimberlite melts be alkali-carbonate liquids: composition of the melt snapshots preserved in deepest mantle xenoliths.Journal of Raman Spectroscopy, in press available, 19p. PdfRussiadeposit - Udachnaya

Abstract: The study of kimberlite rocks is important as they provide critical information regarding the composition and dynamics of the continental mantle and are the principal source of diamonds. Despite many decades of research, the original compositions of kimberlite melts, which are thought to be derived from depths > 150 km, remain highly debatable due to processes that can significantly modify their composition during ascent and emplacement. Snapshots of the kimberlite?related melts were entrapped as secondary melt inclusions hosted in olivine from sheared peridotite xenoliths from the Udachnaya?East pipe (Siberian craton). These xenoliths originated from 180? to 220?km depth and are among the deepest derived samples of mantle rocks exposed at the surface. The crystallised melt inclusions contain diverse daughter mineral assemblages (>30 mineral species), which are dominated by alkali?rich carbonates, sulfates, and chlorides. The presence of aragonite as a daughter mineral suggests a high?pressure origin for these inclusions. Raman?mapping studies of unexposed inclusions show that they are dominated by carbonates (>65 vol.%), whereas silicates are subordinate (<13 vol.%). This indicates that the parental melt for the inclusions was carbonatitic. The key chemical features of this melt are very high contents of alkalis, carbon dioxide, chlorine, and sulfur and extremely low silica and water. Alkali?carbonate melts entrapped in xenolith minerals likely represent snapshots of the primitive kimberlite melt. This composition is in contrast with the generally accepted notion that kimberlites originated as ultramafic silicate water?rich melts. Experimental studies revealed that alkali?carbonate melts are a very suitable diamond?forming media. Therefore, our findings support the idea that some diamonds and kimberlite magmatism may be genetically related.
DS202003-0329
2020
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K.A genetic study of olivine crystallization in the Mark kimberlite ( Canada) revealed by zoning and melt inclusions.Lithos, In press available 46p. pdf.Canada, Northwest Territoriesdeposit - Mark

Abstract: Elucidating the composition of primary kimberlite melts is essential to understanding the nature of their source, petrogenesis, rheology, transport and ultimately the origin of diamonds. Kimberlite rocks are typically comprised of abundant olivine (~2560 vol%), which occurs as individual grains of variable size and morphology, and includes xenocrysts and zoned phenocrysts. Zoning patterns and inclusions in olivine can be used to decipher the petrogenetic history of kimberlites, starting from their generation in the mantle through to emplacement in the crust. This study examines well-preserved, euhedral, zoned olivine crystals from the Mark kimberlite (Lac de Gras, Canada). Olivine typically consists of xenocrystic cores, which are homogeneous in composition but vary widely between grains (Fo88.193.6). These cores are in turn surrounded by (in order of crystallisation) magmatic rims and Mg-rich rinds (Fo95.398.1). In addition, we document a new type of olivine zone (‘outmost rind’) that overgrows Mg-rich rinds. Crystal and melt/fluid inclusions are abundant in olivine and preserve a record of kimberlite melt evolution. For the first time in the studies of kimberlite olivine, we report primary melt inclusions hosted in Mg-rich olivine rinds. In addition, we observe that pseudosecondary melt/fluid inclusions are restricted to interior olivine zones (cores, rims) and are considered to have formed prior to rind formation. Pseudosecondary melt/fluid inclusions are inferred to have been entrapped at depth, as evidenced by measured densities in thermometric experiments of CO2 and decrepitation haloes, indicating a minimum entrapment pressure of ~200450 MPa (or ~615 km). Both primary and pseudosecondary melt inclusions in olivine have daughter minerals dominated by CaMg and K-Na-Ba-Sr-bearing carbonates, K-Na-chlorides along with subordinate silicates (e.g., phlogopite, monticellite), Fe-Mg-Al-Ti-spinel, perovskite, phosphates and sulphates/sulphides and periclase. In addition to phases reported in primary melt inclusions, pseudosecondary melt inclusions contain more diverse and exotic daughter mineral assemblages, where they contain phases such as tetraferriphlogopite Ba- or K-sulphates, kalsilite and Na-phosphates. The daughter mineral assemblages are consistent with a silica-poor, alkali dolomitic carbonatite melt. We demonstrate that the different types of inclusions in olivine can assist in constraining the timing of multi-stage olivine growth and the composition of the crystallising melt. The large variance in olivine zoning patterns, morphologies and Ni distribution (i.e. both coupling with and decoupling from Fo) indicates that olivine in the studied Mark kimberlite samples represent an accumulation of olivine, where olivine was derived from successive stages of the ascending magma and/or from multiple, but related pulses of magma. Primary and pseudosecondary melt/fluid inclusions in olivine indicate that a variably differentiated silica-poor, halogen-bearing, alkali-dolomitic melt crystallised and transported olivine in the Mark kimberlite.
DS202005-0754
2020
Abersteiner, A.Nosova, A.A., Kargin, A.V., Sazonova, L.V., Dubinina, E.O., Chugaev, A.V., Lebedeva, N.M., Yudin, D.S., Larionova, Y.O., Abersteiner, A., Gareev, B.I., Batalin, G.A.Sr-Nd-Pb isotopic systematic and geochronology of ultramafic alkaline magmatism of the southwestern margin of the Siberian craton: metasomatism of the sub-continental lithospheric mantle related to subduction and plume events.Lithos, Vol. 364-365, 21p. PdfRussia, Siberiadeposit - Ilbokich, Chadobets

Abstract: To provide new insights into the origin and evolution of ultramafic lamprophyres (UMLs) and their mantle source, we examined two UML (aillikite and damtjernite) occurrences of different ages in the western portion of the Siberian Craton (Ilbokich and Chadobets). New age, mineral and rock geochemistry, along with Sr-Nd-Pb-C-O isotope data was obtained. Our new 206Pb/238U perovskite age (399 ± 4 Ma) confirms the previously published Early Devonian age of the Ilbokich aillikite. RbSr isochron and 40Ar/39Ar dating yielded a Middle Triassic age (243 ± 3 Ma and 241 ± 1 Ma, respectively) for the Chadobets aillikites, indicating post-Trap emplacement of these rocks. Both UMLs are characterized by incompatible elements, including light rare earth element (LREE) enrichments (La is up to ×200 chondrite concentration), and strong fractionation of REEs ((La/Yb)n: 33-84). Despite the close geochemical affinity of both UMLs, the Nd isotopic compositions of aillikites, as well as the Pb isotopic composition of Chadobets and Ilbokich UMLs, do not overlap and are distinctly different from each other. The initial Sr and Nd isotopic compositions of the Ilbokich UMLs fall in within a narrow 87Sr/86Sr0 range (0.7032-0.7042) and ?Nd(T) (4.03-3.97). Chadobets UMLs have a similar Sr isotopic signature (87Sr/86Sr0: 0.7031-0.7043) and a more depleted Nd isotopic signature (?Nd(T) 4.09-5.08). The initial Pb isotope compositions of the Chadobets UMLs are moderately radiogenic, ranging between 206Pb/204Pb = 18.4-19.0, 208Pb/204Pb = 38.3-38.8, and are characterized by a narrow 207Pb/204Pb ratio between 15.5 and 15.6. The Ilbokich Pb isotope compositions are less variable and range between 206Pb/204Pb = 18.0-18.4, 208Pb/204Pb = 37.8-38.4 and 207Pb/204Pb ratios between 15.5 and 15.6. The oxygen isotopic composition of carbonate from both UMLs is characterized by highly variable ?18O values from +12.1 and up to +20.5‰ (SMOW). The isotopic composition of ?13C values range from ?1.3‰ to ?7.1. Based on the minor impact of crustal contamination in both aillikites, it is inferred that their radiogenic isotope composition reflects a mantle source signature. The mantle source of the Chadobets aillikites is likely to include carbonatitic magma as a metasomatic agent. In contrast, phlogopite-rich metasomes within the lithospheric mantle could have contributed more significantly to the Ilbokich aillikites. These metasomes could be formed during the Caledonian orogeny, which did not only affect the southwestern boundary of the Siberian Craton, but also expanded to the craton interior. This study provides additional support for the evolution of the south-western portion of the Siberian SCLM, ranging from mantle containing phlogopite enrichment domains during the Early Devonian to hydrous-phase reduced mantle in the Triassic due to the thermal impact of the Siberian Traps.
DS202006-0943
2020
Abersteiner, A.Novosa, A.A., Kargin, A.V., Sazonova, L.V., Dubinina, E.O., Chugaev, A.V., Lebedeva, N.M., Yudin, D.S., Larionova, Y.O., Abersteiner, A., Gareev, B.I., Batalin, G.A.Sr-N-Pb isotopic systematic and geochronology of ultramafic alkaline magmatism of the southwestern margin of the Siberian craton: metasomatism of the sub-continental lithospheric mantle related to subduction and plume events.Lithos, Vol. 364-365, 21p. PdfRussiaailikite, damjernite

Abstract: To provide new insights into the origin and evolution of ultramafic lamprophyres (UMLs) and their mantle source, we examined two UML (aillikite and damtjernite) occurrences of different ages in the western portion of the Siberian Craton (Ilbokich and Chadobets). New age, mineral and rock geochemistry, along with Sr-Nd-Pb-C-O isotope data was obtained. Our new 206Pb/238U perovskite age (399 ± 4 Ma) confirms the previously published Early Devonian age of the Ilbokich aillikite. RbSr isochron and 40Ar/39Ar dating yielded a Middle Triassic age (243 ± 3 Ma and 241 ± 1 Ma, respectively) for the Chadobets aillikites, indicating post-Trap emplacement of these rocks. Both UMLs are characterized by incompatible elements, including light rare earth element (LREE) enrichments (La is up to ×200 chondrite concentration), and strong fractionation of REEs ((La/Yb)n: 33-84). Despite the close geochemical affinity of both UMLs, the Nd isotopic compositions of aillikites, as well as the Pb isotopic composition of Chadobets and Ilbokich UMLs, do not overlap and are distinctly different from each other. The initial Sr and Nd isotopic compositions of the Ilbokich UMLs fall in within a narrow 87Sr/86Sr0 range (0.7032-0.7042) and ?Nd(T) (4.03-3.97). Chadobets UMLs have a similar Sr isotopic signature (87Sr/86Sr0: 0.7031-0.7043) and a more depleted Nd isotopic signature (?Nd(T) 4.09-5.08). The initial Pb isotope compositions of the Chadobets UMLs are moderately radiogenic, ranging between 206Pb/204Pb = 18.4-19.0, 208Pb/204Pb = 38.3-38.8, and are characterized by a narrow 207Pb/204Pb ratio between 15.5 and 15.6. The Ilbokich Pb isotope compositions are less variable and range between 206Pb/204Pb = 18.0-18.4, 208Pb/204Pb = 37.8-38.4 and 207Pb/204Pb ratios between 15.5 and 15.6. The oxygen isotopic composition of carbonate from both UMLs is characterized by highly variable ?18O values from +12.1 and up to +20.5‰ (SMOW). The isotopic composition of ?13C values range from ?1.3‰ to ?7.1. Based on the minor impact of crustal contamination in both aillikites, it is inferred that their radiogenic isotope composition reflects a mantle source signature. The mantle source of the Chadobets aillikites is likely to include carbonatitic magma as a metasomatic agent. In contrast, phlogopite-rich metasomes within the lithospheric mantle could have contributed more significantly to the Ilbokich aillikites. These metasomes could be formed during the Caledonian orogeny, which did not only affect the southwestern boundary of the Siberian Craton, but also expanded to the craton interior. This study provides additional support for the evolution of the south-western portion of the Siberian SCLM, ranging from mantle containing phlogopite enrichment domains during the Early Devonian to hydrous-phase reduced mantle in the Triassic due to the thermal impact of the Siberian Traps.
DS202008-1365
2020
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Kjarsgaard, B.A., Fedortchouk, Y., Ehrig, K., Kamenetsky, M.Evolution of kimberlite magmas in the crust: a case study of groundmass and mineral hosted inclusions in the Mark kimberlite ( Lac de Gras, Canada).Lithos, in press available, 55p. PdfCanada, Northwest Territoriesdeposit - Mark

Abstract: Kimberlites are the surface manifestation of deeply-derived (>150 km) and rapidly ascended magmas. Fresh kimberlite rocks are exceptionally rare, as most of them are invariably modified by pervasive deuteric and/or post-magmatic fluids that overprint the original mineralogy. In this study, we examined fresh archetypal kimberlite from the Mark pipe (Lac de Gras, Canada), which is characterised by well-preserved olivine and groundmass minerals. The sequence of crystallisation of the parental melt and its major compositional features, including oxygen fugacity, were reconstructed using textural relationships between magmatic minerals, their zoning patterns and crystal/melt/fluid inclusions. Crystal and multiphase primary, pseudosecondary and secondary melt/fluid inclusions in olivine, Cr-diopside, spinel, perovskite, phlogopite/kinoshitalite, apatite and calcite preserve a record of different stages of kimberlite melt evolution. Melt/fluid inclusions are generally more depleted in silica and more enriched in alkalis (K, Na), alkali-earth (Ba, Sr) and halogens (Cl, F) relative to the whole-rock composition of the Mark kimberlite. These melt/fluid inclusion compositions, in combination with presence of elevated CaO (up to 1.73 wt%), in Mg-rich olivine rinds, crystallisation of groundmass kinoshitalite, carbonates (calcite, Sr-Ba-bearing) and alkali-enriched rims around apatite suggest that there was progressive enrichment in CO2, alkalis and halogens in the evolving parental melt. The Mark kimberlite groundmass is characterised by the following stages of in-situ crystallisation: (1) olivine rims around xenocrystic cores + Cr-spinel/TIMAC. (2) Mg-rich olivine rinds around olivine rims/cores + MUM-spinel (followed by pleonaste and Mg-magnetite) + monticellite (+ partial resorption of olivine, along with the formation of ferropericlase and CO2 as a result of decarbonation reactions) + perovskite + apatite. (3) Olivine outmost rinds, which are coeval with phlogopite/kinoshitalite + apatite + sulphides + carbonate (calcite, Ba-Sr-Na-bearing varieties). In addition, oxygen fugacity of the Mark kimberlite was constrained by olivine-chromite, perovskite and monticellite oxygen barometry and showed that the parental melt became progressively more oxidised in response to fractional crystallisation. (4) Deuteric (i.e. late-stage magmatic) and/or post-magmatic (i.e. external fluids) alteration of magmatic minerals (e.g., olivine, monticellite, ferropericlase) and crystallisation of mesostasis serpentine, K-bearing chlorite and brucite (i.e. replacement of ferropericlase). The absence of any alkali (Na, K) and halogen (F, Cl) rich groundmass minerals in the Mark kimberlite may be attributed to these elements becoming concentrated in the late-stage melt where they potentially formed unstable, water-soluble carbonates (such as those observed in melt inclusions). Consequently, these minerals were most likely removed from the groundmass by deuteric and/or post-magmatic alteration.
DS202008-1395
2019
Abersteiner, A.Golovin, A.V., Sharygin, I., Korsakov, A.V., Abersteiner, A.Can primitive kimberlitic melts be alkali-carbonate liquids: composition of the melt snapshots preserved in deepest mantle xenoliths.Journal of Raman Spectroscopy, doi.org/10.1002/jrs.5701 19p pdfRussiadeposit - Udachnaya-East

Abstract: The study of kimberlite rocks is important as they provide critical information regarding the composition and dynamics of the continental mantle and are the principal source of diamonds. Despite many decades of research, the original compositions of kimberlite melts, which are thought to be derived from depths > 150 km, remain highly debatable due to processes that can significantly modify their composition during ascent and emplacement. Snapshots of the kimberlite?related melts were entrapped as secondary melt inclusions hosted in olivine from sheared peridotite xenoliths from the Udachnaya?East pipe (Siberian craton). These xenoliths originated from 180? to 220?km depth and are among the deepest derived samples of mantle rocks exposed at the surface. The crystallised melt inclusions contain diverse daughter mineral assemblages (>30 mineral species), which are dominated by alkali?rich carbonates, sulfates, and chlorides. The presence of aragonite as a daughter mineral suggests a high?pressure origin for these inclusions. Raman?mapping studies of unexposed inclusions show that they are dominated by carbonates (>65 vol.%), whereas silicates are subordinate (<13 vol.%). This indicates that the parental melt for the inclusions was carbonatitic. The key chemical features of this melt are very high contents of alkalis, carbon dioxide, chlorine, and sulfur and extremely low silica and water. Alkali?carbonate melts entrapped in xenolith minerals likely represent snapshots of the primitive kimberlite melt. This composition is in contrast with the generally accepted notion that kimberlites originated as ultramafic silicate water?rich melts. Experimental studies revealed that alkali?carbonate melts are a very suitable diamond?forming media. Therefore, our findings support the idea that some diamonds and kimberlite magmatism may be genetically related.
DS202008-1411
2020
Abersteiner, A.Korneeva, A.A., Nikolai, N.A., Kamenetsky, V.S., Portnyagin, M.V., Savelyev, D.P., Krasheninnikov, S.P., Abersteiner, A., Kamenetsky, M.B., Zelenski, M.E., Shcherbakov, V.D., Botcharnikov, R.E.Composition, crystallization conditions and genesis of sulfide saturated parental melts of olivine-phyric rocks from Kamchatsky Mys ( Kamchatka, Russia).Lithos, 10.1016/j.lithos.2020.105657Russia, Kamchatkapicrites

Abstract: Sulfide liquids that immiscibly separate from silicate melts in different magmatic processes accumulate chalcophile metals and may represent important sources of the metals in Earth's crust for the formation of ore deposits. Sulfide phases commonly found in some primitive mid-ocean ridge basalts (MORB) may support the occurrence of sulfide immiscibility in the crust without requiring magma contamination and/or extensive fractionation. However, the records of incipient sulfide melts in equilibrium with primitive high-Mg olivine and Cr-spinel are scarce. Sulfide globules in olivine phenocrysts in picritic rocks of MORB-affinity at Kamchatsky Mys (Eastern Kamchatka, Russia) represent a well-documented example of natural immiscibility in primitive oceanic magmas. Our study examines the conditions of silicate-sulfide immiscibility in these magmas by reporting high precision data on the compositions of Cr-spinel and silicate melt inclusions, hosted in Mg-rich olivine (86.9-90 mol% Fo), which also contain globules of magmatic sulfide melt. Major and trace element contents of reconstructed parental silicate melts, redox conditions (?QFM = +0.1 ± 0.16 (1?) log. units) and crystallization temperature (1200-1285 °C), as well as mantle potential temperatures (~1350 °C), correspond to typical MORB values. We show that nearly 50% of sulfur could be captured in daughter sulfide globules even in reheated melt inclusions, which could lead to a significant underestimation of sulfur content in reconstructed silicate melts. The saturation of these melts in sulfur appears to be unrelated to the effects of melt crystallization and crustal assimilation, so we discuss the reasons for the S variations in reconstructed melts and the influence of pressure and other parameters on the SCSS (Sulfur Content at Sulfide Saturation).
DS202108-1266
2021
Abersteiner, A.Abersteiner, A., Kamenetsky, V.S., Golovin, A., Goemann, K., Ehrig, K.Dissolution of mantle orthopyroxene in kimberlitic melts: petrographic, geochemical and melt inclusion constraints from an orthopyroxenite xenolith from the Udachnaya-East kimberlite ( Siberian Craton, Russia).Lithos, Vol. 398-399, 17p. PdfRussia, Siberiadeposit - Udachnaya-East

Abstract: Reconstructing the original composition of kimberlite melts in the mantle and delineating the processes that modify them during magmatic ascent and emplacement in the crust remains a significant challenge in kimberlite petrology. One of the most significant processes commonly cited to drive initial kimberlite melts towards more Si-Mg-rich compositions and decrease the solubility of CO2 is the assimilation of mantle orthopyroxene. However, there is limited direct evidence to show the types of reactions that may occur between mantle orthopyroxene and the host kimberlite melt. To provide new constraints on the interaction between orthopyroxene and parental kimberlite melts, we examined a fresh (i.e. unmodified by secondary/post-magmatic alteration) orthopyroxenite xenolith, which was recovered from the serpentine-free units of the Udachnaya-East kimberlite (Siberian Craton, Russia). This xenolith is composed largely of orthopyroxene (~ 90%), along with lesser olivine and clinopyroxene and rare aluminous magnesian chromite. We can show that this xenolith was invaded by the host kimberlite melt along grain interstices and fractures, where it partially reacted with orthopyroxene along the grain boundaries and replaced it with aggregates of compositionally distinct clinopyroxene, olivine and phlogopite, along with subordinate Fe-Cr-Mg spinel, Fesingle bondNi sulphides and djerfisherite (K6(Fe,Ni,Cu)25S26Cl). Primary melt inclusions in clinopyroxene replacing xenolith-forming orthopyroxene, as well as secondary melt inclusion trails in xenolith orthopyroxene, clinopyroxene and olivine are composed of similar daughter mineral assemblages that consist largely of: Nasingle bondK chlorides, along with varying proportions of phlogopite, Fe-Cu-Ni sulphides, djerfisherite, rasvumite (KFe2S3), Cr-Fe-Mg spinel, nepheline and apatite, and rare rutile, sodalite, barite, olivine, Ca-K-Na carbonates and Nasingle bondK sulphates. The melt entrapped by these inclusions likely represent the hybrid products produced by the invading kimberlite melt reacting with orthopyroxene in the xenolith. The mechanism that could explain the partial replacement of orthopyroxene in this xenolith by clinopyroxene, olivine and phlogopite could be attributed to the following reaction: Orthopyroxene + Carbonatitic (melt) ? Olivine + Clinopyroxene + Phlogopite + CO2. This reaction is supported by theoretical and experimental studies that advocate the dissolution of mantle orthopyroxene within an initially silica-poor and carbonate-rich kimberlite melt. The mineral assemblages replacing orthopyroxene in the xenolith, together with hosted melt inclusions, suggests that the kimberlitic melt prior to reaction with orthopyroxene was likely carbonate-rich and Na-K-Cl-S bearing. The paucity of carbonate in the reaction zones around orthopyroxene and in melt inclusions in clinopyroxene replacing xenolith-forming orthopyroxene and xenolith minerals (orthopyroxene, clinopyroxene and olivine) is attributed to the consumption of carbonates and subsequent exsolution of CO2 by the proposed decarbonation reaction. Concluding, we propose that this orthopyroxenite xenolith provides a rare example of the types of reactions that can occur between mantle orthopyroxene and the host kimberlite melt. The preservation of this xenolith and zones around orthopyroxene present new insights into the composition and evolution of parental kimberlite melts and CO2 exsolution.
DS201706-1095
2017
Abert, C.Marshak, S., Domrois, S., Abert, C., Larson, T., Pavlis, G., Hamburger, M., Yang, X., Gilbert, H., Chen, C.The basement revealed: tectonic insight from a digital elevation model of the Great Unconformity, USA cratonic platform.Geology, Vol. 45, 5, pp. 391-394.United Statestectonics - Mid continent

Abstract: Across much of North America, the contact between Precambrian basement and Paleozoic strata is the Great Unconformity, a surface that represents a >0.4 b.y.-long hiatus. A digital elevation model (DEM) of this surface visually highlights regional-scale variability in the character of basement topography across the United States cratonic platform. Specifically, it delineates Phanerozoic tectonic domains, each characterized by a distinct structural wavelength (horizontal distance between adjacent highs) and/or structural amplitude (vertical distance between adjacent lows and highs). The largest domain, the Midcontinent domain, includes long-wavelength epeirogenic basins and domes, as well as fault-controlled steps. The pronounced change in land-surface elevation at the Rocky Mountain Front coincides with the western edge of the Midcontinent domain on the basement DEM. In the Rocky Mountain and Colorado Plateau domains, west of the Rocky Mountain Front, structural wavelength is significantly shorter and structural amplitude significantly higher than in the Midcontinent domain. The Bordering Basins domain outlines the southern and eastern edges of the Midcontinent domain. As emphasized by the basement DEM, several kilometers of structural relief occur across the boundary between these two domains, even though this boundary does not stand out on ground-surface topography. A plot of epicenters on the basement DEM supports models associating intraplate seismicity with the Midcontinent domain edge. Notably, certain changes in crustal thickness also coincide with distinct changes in basement depth.
DS201312-0003
2013
Abete, T.Abete, T.Deep carbonate recycling and metasomatic enrichment of the sub-continental lithospheric mantle inferred from mantle xenoliths of the East African Rift system.Goldschmidt 2013, AbstractAfricaMetasomatism
DS202112-1920
2021
Abeykon, S.Blanchard. I., Abeykon, S., Frost, D.J., Rubie, D.C.Sulfur content at sulfide saturation of peridotitic melt at upper mantle conditions.American Mineralogist, Vol. 106, pp. 1835-1843. pdfMantlesulfides

Abstract: The concentration of sulfur that can be dissolved in a silicate liquid is of fundamental importance because it is closely associated with several major Earth-related processes. Considerable effort has been made to understand the interplay between the efects of silicate melt composition and its capacity to retain sulfur, but the dependence on pressure and temperature is mostly based on experiments performed at pressures and temperatures below 6 GPa and 2073 K. Here we present a study of the effects of pressure and temperature on sulfur content at sulfide saturation of a peridotitic liquid. We performed 14 multi-anvil experiments using a peridotitic starting composition, and we produced 25 new measurements at conditions ranging from 7 to 23 GPa and 2173 to 2623 K. We analyzed the recovered samples using both electron microprobe and laser ablation ICP-MS. We compiled our data together with previously published data that were obtained at lower P-T conditions and with various silicate melt compositions. We present a new model based on this combined data set that encompasses the entire range of upper mantle pressure-temperature conditions, along with the efect of a wide range of silicate melt compositions. Our findings are consistent with earlier work based on extrapolation from lower-pressure and lower-temperature experiments and show a decrease of sulfur content at sulfide saturation (SCSS) with increasing pressure and an increase of SCSS with increasing temperature. We have extrapolated our results to pressure-temperature conditions of the Earth’s primitive magma ocean, and show that FeS will exsolve from the molten silicate and can efectively be extracted to the core by a process that has been termed the "Hadean Matte." We also discuss briefly the implications of our results for the lunar magma ocean.
DS201910-2240
2019
Abeykoon, S.Abeykoon, S., Frost, D.J., Laurenz, V., Miyajima, N.A new geothermometer based on the oxygen content of sulphide inclusions in diamonds.Goldschmidt2019, 1p. AbstractMantlegeothermometry

Abstract: Sulphides are the most common type of inclusions found in diamonds and are widely used to determine the timing and lithology of diamond formation. Typical inclusions are monosulfide solid solutions (MSS) in the Fe-Ni-S system with minor amounts of Cu, Co and Mo. Previous experimental studies show that oxygen partitions into sulphide melts but most importantly measurements of natural sulphide inclusions indeed show measureable oxygen concentrations. If the parameters that control sulphide oxygen concentration can be determined then they could be potentially used to understand formation conditions of diamonds. We performed a series of high pressure (3-11 GPa) and high temperature (1573-1973 K) experiments in order to parameterize the oxygen content in sulphides in equilibrium with a mantle peridotite assemblage relevant to diamond formation. Multi-anvil experiments were carried out in graphite capsules and a peridotite silicate composition was equilibrated with molten FeS for at least 5 hrs. Run products that contained mantle silicate minerals and quenched sulphide melts were analysed using the electron microprobe. In some cases Ir was added in sufficient quantities to saturate the sulphides and form an Fe-Ir alloy from which the oxygen fugacity could be accurately determined. We measured up to 16 weight % of FeO in our experimental sulphide melts at mantle conditions. Moreover, the content of oxygen in the sulphide is found to be not controlled by fO2 or fS2, which is in disagreement with previous experimental studies conducted at ambient pressure conditions. The experiments indicate that the oxygen concentration is mainly controlled by the FeO activity in coexisting silicate phases and the temperature. In order to fit the data and to account for the observed FeO dependence, we developed a thermodynamic model using an end-member equilibrium between olivine, pyroxene and FeO in the sulphide melt. Using this relationship with measurements of oxygen in natural sulphide inclusions in diamonds reveals temperatures for lithospheric diamond formation in the range of 1140 – 1410 ºC.
DS202006-0917
2020
Abeysinghe, B.Dushyantha, N., Batapola, N., Ilankoon, I.M.S.K., Rohitha, S., Premasiri, R., Abeysinghe, B., Ratnayake, N., Dissanayake, K.The story of rare earth elements ( REES): occurrences, global distribution, genesis, geology, mineralogy and global production.Ore Geology Reviews, Vol. 122, 17p. PdfGlobalREE

Abstract: Rare earth elements (REEs) including fifteen lanthanides, yttrium and scandium are found in more than 250 minerals, worldwide. REEs are used in various high-tech applications across various industries, such as electrical and electronics, automotive, renewable energy, medical and defence. Therefore, the demand for REEs in the global market is increasing day by day due to the surging demand from various sectors, such as emerging economies, green technology and R&D sectors. Rare earth (RE) deposits are classified on the basis of their genetic associations, mineralogy and form of occurrences. The Bayan Obo, Mountain Pass, Mount Weld and China’s ion adsorption clays are the major RE deposits/mines in the world to date and their genesis, chronology and mineralogy are discussed in this review. In addition, there are other RE deposits, which are currently being mined or in the feasibility or exploration stages. Most of the RE resources, production, processing and supply are concentrated in the Asia-Pacific region. In this regard, China holds the dominancy in the RE industry by producing more than 90% of the current rare earth requirements. Thus, REEs are used as a powerful tool by China in trade wars against other countries, especially against USA in 2019. However, overwhelming challenges in conventional RE explorations and mining make secondary RE resources, such as electric and electronic waste (e-waste) and mine tailings as promising resources in the future. Due to the supply risk of REEs and the monopoly of the REEs market, REEs recycling is currently considered as an effective method to alleviate market fluctuations. However, economical and sustainable processing techniques are yet to be established to exploit REEs via recycling. Moreover, there are growing ecological concerns along with social resistance towards the RE industry. To overcome these issues, the RE industry needs to be assessed to maintain long-term social sustainability by fostering the United Nations sustainable development goals (SDGs).
DS201709-2067
2017
Abhinay, K.Upadhyay, D., Ranjan, S., Abhinay, K., Pruseth, K.L., Nanda, J.K.India-Antarica connection: constraints from deformed alkaline rocks and carbonatites.Goldschmidt Conference, abstract 1p.Indiacarbonatites

Abstract: Deformed Alkaline Rocks and Carbonatites (DARCs) are markers of suture zones where continents have rifted apart and later amalgamated [1]. Petrological and geochronological data indicates that parts of India and East Antarctica may have been involved in several episodes of collision and breakup during the assembly of past supercontinents [2]. DARCs at the eastern margin of the Eastern Ghats Province (EGP) in India preserve the record of these amalgamation and breakup events. It is thought that the Napier Complex of East Antarctica collided with the Dharwar Craton of India at ca. 1.60 Ga forming the central and eastern Indian shield [3]. New zircon U-Pb ages from DARCs at the EGP margin show that the alkaline complexes (Kamakhyanagar: 1350±14 Ma Rairakhol: 1379±6 Ma; Khariar: 1478±5 Ma; Koraput: 1387±34 Ma; Kunavaram: 1360±5 Ma; Jojuru: 1352±6 Ma) were emplaced in a narrow time interval. The alkaline magmatism marks an episode of rifting in the Indo-Antarctic continental fragment, correlatable with breakup of the Columbia supercontinent. Metamorphic zircon from the alkaline rocks furnish age populations at 917-950 Ma, 792- 806 Ma and 562-569 Ma. The 917-950 Ma ages are correlated with the closure of an oceanic basin between the Ruker Terrane of East Antarctica and the Indian Shield during the assembly of the Rodinia supercontinent. This led to the collision of the Ruker Terrane with the combined India-Napier Complex producing the Grenville-age EGPRayner Complex orogen [2, 3]. The 792-806 Ma ages record the disintegration of Rodinia when Greater India started to break away from East Antarctica [4]. In the early Paleozoic, India reconverged towards Antarctica and Australia during Gondwanaland assembly. The 562-569 Ma zircon ages date the resulting collisions during Pan-African orogenesis.
DS201710-2272
2017
Abhinay, K.Upadhyay, D., Ranjan, S., Abhinay, K., Pruseth, K.L., Nanda, J.K.India-Antarctica connection: constraints from deformed alkaline rocks and carbonatites.Goldschmidt Conference, 1p. AbstractIndiacarbonatites

Abstract: Re-Os and platinum group element analyses are reported for peridotite xenoliths from the 533 Ma Venetia kimberlite cluster situated in the Limpopo Mobile Belt, the Neoarchaean collision zone between the Kaapvaal and Zimbabwe Cratons. The Venetian xenoliths provide a rare opportunity to examine the state of the cratonic lithosphere prior to major regional metasomatic disturbance of Re-Os systematics throughout the Phanerozoic. The 32 studied xenoliths record Si-enrichment that is characteristic of the Kaapvaal lithospheric mantle and can be subdivided into five groups based on Re-Os analyses. The most pristine group I samples (n = 13) display an approximately isochronous relationship and fall on a 3.28 ± 0.17 Ga (95 % conf. int.) reference line that is based on their mean TMA age. This age overlaps with the formation age of the Limpopo crust at 3.35-3.28 Ga. The group I samples derive from ?50 to ?170 km depth, suggesting coeval melt depletion of the majority of the Venetia lithospheric mantle column. Group II and III samples have elevated Re/Os due to Re addition during kimberlite magmatism. Group II has otherwise undergone a similar evolution as the group I samples with overlapping 187Os/188Os at eruption age: 187Os/188OsEA, while group III samples have low Os concentrations, unradiogenic 187Os/188OsEA and were effectively Re-free prior to kimberlite magmatism. The other sample groups (IV and V) have disturbed Re-Os systematics and provide no reliable age information. A strong positive correlation is recorded between Os and Re concentrations for group I samples, which is extended to groups II and III after correction for kimberlite addition. This positive correlation precludes a single stage melt depletion history and indicates coupled remobilisation of Re and Os. The combination of Re-Os mobility, preservation of the isochronous relationship, correlation of 187Os/188Os with degree of melt depletion and lack of radiogenic Os addition puts tight constraints on the formation and subsequent evolution of Venetia lithosphere. First, melt depletion and remobilisation of Re and Os must have occurred within error of the 3.28 Ga mean TMA age. Second, the refractory peridotites contain significant Re despite recording >40 % melt extraction. Third, assuming that Si-enrichment and Re-Os mobility in the Venetia lithospheric mantle were linked, this process must have occurred within ?100 Myr of initial melt depletion in order to preserve the isochronous relationship. Based on the regional geological evolution, we propose a rapid recycling model with initial melt depletion at ?3.35 Ga to form a tholeiitic mafic crust that is recycled at ?3.28 Ga, resulting in the intrusion of a TTG suite and Si-enrichment of the lithospheric mantle. The non-zero primary Re contents of the Venetia xenoliths imply that TRD model ages significantly underestimate the true depletion age even for highly depleted peridotites. The overlap of the ?2.6 Ga TRD ages with the time of the Kaapvaal-Limpopo collision is purely fortuitous and has no geological significance. Hence, this study underlines the importance of scrutiny if age information is to be derived from whole rock Re-Os analyses.
DS200712-0001
2007
Abo-Ezz, E.R.Abdelrahman, E.M., Abo-Ezz, E.R., Soliman, K.S., El-Araby, T.M., Essa, K.S.A least squares window curve method for interpretation of magnetic anomalies caused by dipping dikes.Pure and Applied Geophysics, Vol. 164, 5, May pp. 1027-1044.CanadaGeophysics - airborne magnetics
DS2002-0007
2002
Aboriginal Community Development and the Mineral IndustryAboriginal Community Development and the Mineral IndustryAnnual conference proceedings Vol.s[email protected], 1993-2001 listing of conference proceedingsCanadaMineral development - partnerships, legal
DS1990-1386
1990
Abouassaleh, K.Sobolev, N.V., Abouassaleh, K., Kepezhinskas, K.B., ledneva, V.P.Lamprophyres of Cretaceous diatremes of the Syrian rift.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 314, No. 2, pp. 435-439SyriaLamprophyres, Diatremes
DS1992-0138
1992
Abouchami, W.Boher, M., Abouchami, W., Michard, A., Albarede, F., Arndt, N.T.Crustal growth in West Africa at 2.1 GaJournal of Geophysical Research, Vol. 97, No. B1, January 10, pp. 345-369GlobalGeophysics, Craton
DS1989-0002
1989
Abouchamy, W.Abouchamy, W., Boher, M., Michard, A., Albarede, E., et al.Crustal growth in West Africa at 2.1 Ga: preliminary resultsEos, Vol. 70, No. 15, April 11, p. 485. (abstract.)West Africa, Mauritania, Senegal, Mali, Guinea, Ivory CoastGhana, Burkina Faso, Tectonics, Geochronology
DS1991-1095
1991
Abousetta, A.McClay, K.R., Waltham, D.A., Scott, A.D., Abousetta, A.Physical and seismic modelling of listric normal fault geometriesThe geometry of normal faults, editors Roberts, A.M., Yielding, G., No. 56, pp. 231-239GlobalStructure -faults, Fault geometry -listric
DS2001-0003
2001
Abraham, A.C.Abraham, A.C., Francis, D., Polve, M.Recent alkaline basalts as probes of the lithospheric mantle roots of the Northern Canadian Cordillera.Chemical Geology, Vol. 175, pp. 361-86.Yukon, British Columbia, CordilleraTectonics, Geochronology
DS2003-0423
2003
Abraham, A.C.Francis, D., Abraham, A.C.Interrogating the Cordillera lithosphere with mafic volcanics and mantle xenolithsGeological Association of Canada Annual Meeting, Abstract onlyNorthwest TerritoriesXenoliths
DS200412-0577
2003
Abraham, A.C.Francis, D., Abraham, A.C.Interrogating the Cordillera lithosphere with mafic volcanics and mantle xenoliths.Geological Association of Canada Annual Meeting, Abstract onlyCanada, Northwest TerritoriesXenoliths
DS1994-0008
1994
Abraham, A.P.G.Abraham, A.P.G., Davis, D.W., Kamo, S.L., Spooner, E.T.C.Geochronlogical constraints on late Archean magmatism deformation and gold quartz vein mineralization AnialikCanadian Journal of Earth Sciences, Vol. 31, No. 8, Aug. pp. 1365-1383Northwest TerritoriesGreenstone belt, gold, deformation, Anialik River
DS1995-0005
1995
Abraham, A.P.G.Abraham, A.P.G., Spooner, E.T.C.Late Archean regional deformation and structural controls on gold quartzvein mineralization Slave ProvinceCanadian Journal of Earth Sciences, Vol. 32, No. 8, Aug. pp. 1132-1171Northwest TerritoriesGold, structure, tectonics, Anialik greenstone belt
DS1860-0529
1887
Abraham, F.Abraham, F.Die Diamant Gesellschaften SuedafrikasBerlin: Steinitz, 115P.Africa, South AfricaHistory, Economics
DS200412-1532
2003
AbrahamsenPersonen, L.J., Elming, Mertansen, Pisarvesky, D' Agrilla Filho, Meert, Schmidt, Abrahamsen, BylundPaleomagnetic configuration of continents during the Proterozoic.Tectonophysics, Vol. 375, 1-4, pp. 289-324.MantleMagnetics
DS201112-0280
2011
Abrajevitch, A.Dominguez, A.R., Van der Voo, R., Torsvik, T.H., Hendriks, B.W.H, Abrajevitch, A., Domeier, M., Larsen, B.T., Rousse, S.The ~270 Ma paleolatitude of Baltica and its significance for Pangea models.Geophysical Journal International, In press availableEurope, Baltic ShieldGeochronology
DS200612-1129
2006
Abramov, S.S.Rass, I.T., Abramov, S.S., Utenkov, V.A., Kozlovskii, V.M., Korpechkov, D.I.Role of fluid in the genesis of carbonatites and alkaline rocks: geochemical evidence.Geochemistry International, Vol. 44, 7. pp. 656-664.RussiaCarbonatite
DS202007-1121
2020
Abramov, S.S.Abramov, S.S., Rass, I.T., Kononkova, N.N.Fenites of the Miaskite carbonatite complex in the Vishnevye Mountains, southern Urals, Russia: origin of the metasomatic zoning and thermodynamic simulations of the processes.Petrology, Vol. 28, 3, pp. 298-323. pdfRussia, Uralscarbonatite

Abstract: Mineral zoning in fenites around miaskite intrusions of the Vishnevye Mountains complex can be interpreted as a magmatic-replacement zonal metasomatic aureole (in D.S. Korzhinskii’s understanding): the metasomatic transformations of the fenitized gneisses under the effect of deep alkaline fluid eventually resulted in the derivation of nepheline syenite eutectic melt. Based on the P-T-fO2 parameters calculated from the composition of minerals coexisting in the successive zones, isobaric-isothermal fO2-aSiO2 and µNa2O-µAl2O3 sections were constructed with the Perplex program package to model how the fenites interacted with H2O-CO2 fluid (in the Na-K-Al-Si-Ca-Ti-Fe-Mg-O-H-C system). The results indicate that the fluid-rock interaction mechanisms are different in the outer (fenite) and inner (migmatite) parts of the zonal aureole. Its outer portion was dominated by desilication of rocks, which led, first, to quartz disappearance from these rocks and then to an increase in the Al# of the coexisting minerals (biotite and clinopyroxene). In the inner part of the aureole, fenite transformations into biotite-feldspathic metasomatic rocks and nepheline migmatite were triggered by an increase in the Na and Al activities in the system alkaline H2O-CO2 fluid-rock. As a consequence, the metasomatites were progressively enriched in Al2O3 and alkalis, and these transformations led to the development of biotite in equilibrium with K-Na feldspar and calcite at the sacrifice of pyroxene. The further introduction of alkalis led to the melting of the biotite-feldspathic metasomatites and the origin of nepheline migmatites. The simulated model sequence of metasomatic zones that developed when the gneiss was fenitized and geochemical features of the successive zones (differences in the LILE and REE concentrations in the rocks and minerals of the fenitization aureole and the Sm-Nd isotope systematics of the rocks of the alkaline complex) indicate that the source of the fluid responsible for the origin of zonal fenite-miaskite complexes may have been carbonatite, a derivative of mantle magmas, whereas the miaskites were produced by metasomatic transformations of gneisses and subsequent melting under the effect of fluid derived from carbonatite magmas.
DS202010-1824
2020
Abramov, S.S.Abramov, S.S., Rass, I.T., Kononkova, N.N.Fenites of the Miasite-carbonatite complex in the Vishevye Mountains, southern Urals, Russia: origin of the metasomatic zoning and thermodynamic simulations of the processes.Petrology, Vol. 28, 3, pp. 263-286.Russia, Uralscarbonatite

Abstract: Mineral zoning in fenites around miaskite intrusions of the Vishnevye Mountains complex can be interpreted as a magmatic-replacement zonal metasomatic aureole (in D.S. Korzhinskii’s understanding): the metasomatic transformations of the fenitized gneisses under the effect of deep alkaline fluid eventually resulted in the derivation of nepheline syenite eutectic melt. Based on the P-T-fO2 parameters calculated from the composition of minerals coexisting in the successive zones, isobaric-isothermal fO2-aSiO2 and µNa2O-µAl2O3 sections were constructed with the Perplex program package to model how the fenites interacted with H2O-CO2 fluid (in the Na-K-Al-Si-Ca-Ti-Fe-Mg-O-H-C system). The results indicate that the fluid-rock interaction mechanisms are different in the outer (fenite) and inner (migmatite) parts of the zonal aureole. Its outer portion was dominated by desilication of rocks, which led, first, to quartz disappearance from these rocks and then to an increase in the Al# of the coexisting minerals (biotite and clinopyroxene). In the inner part of the aureole, fenite transformations into biotite-feldspathic metasomatic rocks and nepheline migmatite were triggered by an increase in the Na and Al activities in the system alkaline H2O-CO2 fluid-rock. As a consequence, the metasomatites were progressively enriched in Al2O3 and alkalis, and these transformations led to the development of biotite in equilibrium with K-Na feldspar and calcite at the sacrifice of pyroxene. The further introduction of alkalis led to the melting of the biotite-feldspathic metasomatites and the origin of nepheline migmatites. The simulated model sequence of metasomatic zones that developed when the gneiss was fenitized and geochemical features of the successive zones (differences in the LILE and REE concentrations in the rocks and minerals of the fenitization aureole and the Sm-Nd isotope systematics of the rocks of the alkaline complex) indicate that the source of the fluid responsible for the origin of zonal fenite-miaskite complexes may have been carbonatite, a derivative of mantle magmas, whereas the miaskites were produced by metasomatic transformations of gneisses and subsequent melting under the effect of fluid derived from carbonatite magmas.
DS1975-0218
1976
Abramov, V.A.Abramov, V.A., Popolitov, E.I.Geochemical Properties of Xenoliths of Upper Mantle RocksDoklady Academy of Science USSR, Earth Science Section., Vol. 231, No. 1-6, PP. 172-175.RussiaGeochemistry, Kimberlite, Garnet
DS202010-1843
2020
Abramova, V.D.Erofeeva, K.G., Samsonov, A.V., Stepanova, A.V., Larionova, Yu.O., Dubinina, E.O., Egorova, S.V., Arzamastesev, A.A., Kovalchuk, E.V., Abramova, V.D.Olivine and clinopyroxene phenocrysts as a proxy for the origin and crustal evolution of primary mantle melts: a case study of 2.40 Ga mafic sills in the Kola-Norwegian Terrane, northern Fennoscandia.Petrology, Vol. 28, 4, pp. 338-356. pdfEurope, Norway, Kola Peninsulamelting

Abstract: New petrographic, geochemical, and isotopic (Sr, Nd, and ?18?) data on olivine and pyroxene phenocrysts provide constraints on the composition and crustal evolution of primary melts of Paleoproterozoic (2.40 Ga) picrodoleritic sills in the northwest Kola province, Fennoscandian Shield. The picrodolerites form differentiated sills with S-shaped compositional profiles. Their chilled margins comprise porphyritic picrodolerite (upper margin) and olivine gabbronorite (bottom) with olivine and clinopyroxene phenocrysts. Analysis of the available data allows us to recognize three main stages in the crystallization of mineral assemblages. The central parts of large (up to 2 mm) olivine phenocrysts (Ol-1-C) crystallized at the early stage. This olivine (Mg# 85-92) is enriched in Ni (from 2845 to 3419 ppm), has stable Ni/Mg ratio, low Ti, Mn and Co concentrations, and contains tiny (up to 10 ?m) diopside-spinel dendritic lamella that probably originated due to the exsolution from high Ca- and Cr- primary magmatic olivine. All these features of Ol-1-C are typical of olivine from primitive picritic and komatiitic magmas (De Hoog et al., 2010; Asafov et al., 2018). Ol-1-C contains large (up to 0.25 mm) crystalline inclusions of high-Al enstatite (Mg# 80-88) and clinopyroxene (Mg# 82-90), occasionally in association with Ti-pargasite and chromian spinel (60.4 wt.% Al2O3). These inclusions are regarded as microxenoliths of wall rock that were captured by primary melt at depths more than 30 km and preserved due to the conservation in magmatic olivine. The second stage was responsible for the crystallization of Ol-1 rim (Ol-1-R), small (up to 0.3 mm) olivine (Ol-2, Mg# 76-85) grains, and central parts of large (up to 1.5 mm) clinopyroxene (Cpx-C) phenocrysts in the mid-crustal transitional magma chamber (at a depth of 15-20 km) at 1160-1350°C. At the third stage, Cpx-C phenocrysts were overgrown by low-Mg rims (Mg# 70-72) similar in composition to the groundmass clinopyroxene from chilled picrodolerite and gabbro-dolerite in the central parts of the sills. This stage likely completed the evolution of picrodoleritic magma and occurred in the upper crust at a depth of about 5 km. All stages of picrodoleritic magma crystallization were accompanied by contamination. Primary melts were contaminated by upper mantle and/or lower crust as recognized from xenocrystic inclusions in Ol-1-C. The second contamination stage is supported by the negative values of ?Nd(2.40) = -1.1 in clinopyroxene phenocrysts. At the third stage, contamination likely occurred in the upper crust when ascending melts filled gentle fractures. This caused vertical whole-rock Nd heterogeneity in the sills (Erofeeva et al., 2019), and difference in Nd isotopic composition of clinopyroxene phenocrysts and doleritic groundmass. It was also recognized that residual evolved melts are enriched in radiogenic strontium but have neodymium isotopic composition similar to other samples. It could be explained by the interaction of the melts with fluid formed via decomposition of biotite from surrounding gneisses under the effect of high-temperature melts.
DS1990-0102
1990
Abramovich, I.I.Abramovich, I.I., Klushin, I.G.Geodynamics and metallogeny of folded beltsA.a. Balkema Publ, 255pRussiaBook -ad, Metallogeny -folded belts
DS1986-0797
1986
Abramovich, M.G.Tauson, V.L., Abramovich, M.G.Polymorphism of crystals and phase dimensional effect: graphite- diamondtransformation. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 287, No. 1, pp. 201-205RussiaDiamond morphology
DS1987-0727
1987
Abramovitch, M.G.Tauson, V.L., Abramovitch, M.G.Polymorphism of crystals and the phase size effect: the graphite diamondtransitionDoklady Academy of Science USSR, Earth Science Section, Vol. 287, No. 1-6, pp. 148-152RussiaBlank
DS1997-0006
1997
Abramovitz, T.Abramovitz, T., Berthelsen, A., Thybo, H.Proterozoic sutures and terranes in the southeastern Baltic Shield interpreted from BABEL deep seismic data.Tectonophysics, Vol. 270, No. 3/4, March 15, pp. 259-278.Sweden, Norway, Baltic ShieldGeophysics - seismic BABEL, Tectonics
DS2002-0122
2002
Abramovitz, T.Bayer, U., Thybo, H., Abramovitz, T.Inter wedging and inversion structures around the trans European suture zone in the Baltic sea, a manifestation of compressive tectonic phases.Tectonophysics, Vol. 360, 1-4, pp. 265-80.Europe, Baltic SeaTectonics
DS1983-0527
1983
Abrams, G.Raab, P., Moss, C., Abrams, G.Aeromagnetic Dat a from Southeastern MissouriUnited States Geological Survey (USGS) GD 83-004, DOI/DF 83-005., GlobalMid Continent
DS1990-0103
1990
Abrams, G.A.Abrams, G.A., Grauch, V.J., Bankey, V.Complete bouguer gravity anomaly map of the Uinta and Piceance basins andvicinity, Utah and ColoradoUnited States Geological Survey (USGS) Open File, No. MF-2008-D, 1 : 500, 000Utah, Colorado PlateauGeophysics -gravity, Map
DS1994-0009
1994
Abrams, G.A.Abrams, G.A., Knepper, D.H.Complete bouguer gravity anomaly isostatic residual gravity, gradient and terrain mapsUnited States Geological Survey (USGS), GP-1009, 1: 1 M.ColoradoGeophysics -gravity, Map
DS1993-1808
1993
Abramson, E.H.Zaug, J.M., Abramson, E.H., Brown, J.M., Slutsky, L.J.Second velocites in olivine at earth mantle pressuresScience, Vol. 260, No. 5113, June 4, pp. 1487-1488.MantleOlivine
DS200812-0001
2008
Abrates, M.Abrates, M., Viererck-Goette, L., Ulyych, J., Munsel, D.Melilitic rocks of the CECIP examples from Vogtland W. Bohemia.Goldschmidt Conference 2008, Abstract p.A2.Europe, Germany, Czech RepublicMelilitite
DS2000-0350
2000
AbreuGorayeb, P.S.S., Moura, C.A.V., Gaudette, H.E., AbreuTransamazonic evolution of Sao Luis Craton and northwest Ceara Brasil - and its coerrelation with west Africa.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, West AfricaCraton - tectonics, Magmatism
DS1983-0001
1983
Abreu, P.D.A.Abreu, P.D.A., Munhoz, D.T.V.A Paleogeographic Reconstruction and a Study of Heavy Minerals As An indicator of Primary Diamond Sources in the Serra Do Espinhaco, Minasgerais.(in Portugese).In: Geology of the Precambrian, Geological Society Brasil, Geol. Bol, Vol. 3, pp. 219-234BrazilHeavy Minerals, Alluvials
DS201709-1949
2017
Abritis, A.Abritis, A., McCook, A.Cash bonuses for peer reviewed papers go global. Overview citing Chin a excessive payments.Retraction Watch, Aug. 10, 3p.Global, Chinaresearch papers

Abstract: China is well known for the generous bonuses it pays scientists who land a peer-reviewed publication in a prestigious research journal. But scientists in many countries are reaping similar bounties. After spotting a discussion on a scholarship listserv about the topic, we dug further to find official documents on such payments from institutions named in the thread. Searching the internet using key terms such as “publishing cash incentives” and “schemes cash publishing” widened our net. We relied mostly on online documents in English, so we surely missed some policies. The numbers in the graphic below represent the maximum amounts we uncovered at a particular institution in a specific country. Even under those constraints, we documented publishing incentives from all corners of the globe, including at a number of U.S. institutions. Awards are primarily cash; some are as small as the $10 that Oakwood University in Huntsville, Alabama, bestows on authors when their papers are cited in the literature. Some institutions designate payments for faculty members, whereas others reward student authors.
DS2001-1057
2001
AbsarShanker, R., Nag, S., Ganguly, A., Absar, Rawat, SinghAre Majhgawan Hinota pipe rocks truly group I kimberlite?Indian Acad. Sciences Earth and Plan., Vol. 110, No. 1, pp. 63-76.IndiaKimberlite - classification, Deposit - Majhgawan
DS1998-1582
1998
Abson, J.P.Williams, C.M., Robey, J.A., Abson, J.P.Petrography and mineral chemistry of the Mwenezi - 01 kimberlite, Zimbabwe.7th International Kimberlite Conference Abstract, pp. 955-7.ZimbabwePetrography, geothermometry, Deposit - Mwenezi-01
DS201312-0957
2013
Abson, J.P.Ward, J.D., De Wit, M.C., Revitt, A.W., Abson, J.P.Geological and economic aspects of the Proterozoic Umkondo Group diamond placer near Marange, Zimbabwe.Geoforum , 32ppt. AvailableAfrica, ZimbabweDeposit - Marange area
DS1989-0003
1989
Abstract volumeAbstract volumeMining environment in the '90s. 95th Annual ConventionNorthwest Mining Association, Dec. 6-8, 1989GlobalNorthwest Mining Convention, Mineral deposits
DS201112-1146
2011
Abt, D.Yuan, H., Romanowicz, B., Fischer, K., Abt, D.3-D shear wave radially and azimuthally anisotropic velocity model of the North American upper mantle.Geophysical Journal International, in press Jan. 17Canada, United StatesGeophysics - seismics
DS201012-0200
2010
Abt, D.L.Fischer, K.M., Ford, H.A., Abt, D.L., Rychert, C.A.The lithosphere asthenosphere boundary.Annual Review of Earth and Planetary Sciences, Vol. 38, pp. 551-575.MantleBoundary
DS201112-0334
2010
Abt, D.L.Ford, H.A., Fischer, K.M., Abt, D.L., Rychert, C.A., Elkins-Tanton, L.T.The lithosphere asthenosphere boundary and cratonic lithospheric layering beneath Australia from Sp wave imaging.Earth and Planetary Science Letters, Vol. 300, 3-4, pp. 299-310.AustraliaGeophysics - seismics
DS201312-0004
2013
Abu-Alam, T.S.Abu-Alam, T.S., Santosh, M., Brown, M.,Stuwe, K.Gondwana collision.Mineralogy and Petrology, Vol. 107, pp. 631-634.MantleKenoraland
DS1989-0004
1989
Abyzov, A.M.Abyzov, A.M., Smirnov, E.P.Chromatographic spectra of thermal-description of CO, CO2, and H2O from graphite and diamond.(Russian)Kinet. Catal., (Russian), Vol. 30, No. 4, Jul-Aug. pp. 796-802RussiaDiamond morphology, Chromatographic spectra
DS201012-0001
2010
Abzalov, M.Z.Abzalov, M.Z.Use of twinned drillholes in mineral resource estimation.Exploration and Mining Geology, Vol. 118, 1-4, pp. 13-23.TechnologyQuality control - not specific to diamonds
DS201809-2100
2018
Accardo, N.Tepp, G., Ebinger, C.J., Zal, H., Gallacher, R., Accardo, N., Shillington, D.J., Gaherty, J., Keir, D., Nyblade, A.A., Mbogoni, G.J., Chindandali, P.R.N., Ferdinand-Wambura, R., Mulibo, G.D., Kamihanda, G.Seismic anistrotropy of the Upper mantle below the western rfit, East Africa.Journal of Geophysical Research, Vol. 123, 7, pp. 5644-5660.Africa, east Africageophysics - seismic

Abstract: Although the East African rift system formed in cratonic lithosphere above a large?scale mantle upwelling, some sectors have voluminous magmatism, while others have isolated, small?volume eruptive centers. We conduct teleseismic shear wave splitting analyses on data from 5 lake?bottom seismometers and 67 land stations in the Tanganyika?Rukwa?Malawi rift zone, including the Rungwe Volcanic Province (RVP), and from 5 seismometers in the Kivu rift and Virunga Volcanic Province, to evaluate rift?perpendicular strain, rift?parallel melt intrusion, and regional flow models for seismic anisotropy patterns beneath the largely amagmatic Western rift. Observations from 684 SKS and 305 SKKS phases reveal consistent patterns. Within the Malawi rift south of the RVP, fast splitting directions are oriented northeast with average delays of ~1 s. Directions rotate to N?S and NNW north of the volcanic province within the reactivated Mesozoic Rukwa and southern Tanganyika rifts. Delay times are largest (~1.25 s) within the Virunga Volcanic Province. Our work combined with earlier studies shows that SKS?splitting is rift parallel within Western rift magmatic provinces, with a larger percentage of null measurements than in amagmatic areas. The spatial variations in direction and amount of splitting from our results and those of earlier Western rift studies suggest that mantle flow is deflected by the deeply rooted cratons. The resulting flow complexity, and likely stagnation beneath the Rungwe province, may explain the ca. 17 Myr of localized magmatism in the weakly stretched RVP, and it argues against interpretations of a uniform anisotropic layer caused by large?scale asthenospheric flow or passive rifting.
DS201212-0001
2012
Accredited Gemologists AssociationAccredited Gemologists AssociationThrough the looking glass - the future of diamonds. Panel discussion - Lucent new technology; HPHT diamond technology; Diamond supply? (Coopersmith)Conference Las Vegas May 31, Held May 31TechnologyPanel discussion
DS201702-0234
2016
Acededo, R.D.Presser, J.L.B., Farina-Dolsa, S., Larroza-Cristaldo, F.A., Rocca, M., Alonso, R.N., Acededo, R.D., Cabral-Antunez, N.D., Baller, L., Zarza-Lima, P.R., Sekatcheff, J.M.Modeled mega impact structures in Paraguay: II the eastern region. **PortBoletin del Museo Nacional de Historia Narural del Paraguay, Vol. 20, 2, pp. 205-213. pdf available in * PortSouth America, ParaguayImpact Crater

Abstract: We report here the discovery and study of several new modeled large impact craters in Eastern Paraguay, South America. They were studied by geophysical information (gravimetry, magnetism), field geology and also by microscopic petrography. Clear evidences of shock metamorphic effects were found (e.g., diaplectic glasses, PF, PDF in quartz and feldspar) at 4 of the modeled craters: 1) Negla: diameter:~80-81 km., 2) Yasuka Renda D:~96 km., 3) Tapyta, D: ~80 km. and 4) San Miguel, D: 130-136 km. 5) Curuguaty, D: ~110 km. was detected and studied only by geophysical information. Target-rocks range goes from the crystalline Archaic basement to Permian sediments. The modeled craters were in some cases cut by tholeiitic/alkaline rocks of Mesozoic age and partially covered by lavas of the basaltic Mesozoic flows (Negla, Yasuka Renda, Tapyta and Curuguaty). One of them was covered in part by sediments of Grupo Caacupé (age: Silurian/Devonian). Some of these modeled craters show gold, diamonds, uranium and REE mineral deposits associated. All new modeled large impact craters are partially to markedly eroded.
DS201707-1359
2017
Acevedo, R.D.Presser, J.L.B., Vladykin, N.V., Bitschene, P.R., Tondo, M.J., Acevedo, R.D., Alonso, R., Benitez, P.Olivine-lamproite from Ybtyruzu lamproite field, eastern Paraguay. *** In SpaPyroclastic Flow *** Spa, Vol. 7, 1, pp. 1-15.South America, Paraguaylamproite

Abstract: Numerous Mesozoic bodies of lamproite-like intrusions are located NE and E of the city of Villarrica, Guairá Department, in eastern Paraguay. This magmatic field, known as Ybytyruzú Field, lies immediately on the margin of the SW part of Paranapanemá cratonic-block, just of the Asunción rift backs-horst and so related to deep crustal/lithospheric fracture zones.Mostly of observed rocks are weathered, however fresh samples were collected in dykes from Acaty (=Yzu-2), Tacuarita (=Yzu-7); lava/breccias from Mbocayaty (=Yzu-3); and sill from Salto Boni (=Yzu-6). They intrude, both, the sediments (Independencia Group and Misiones Formation) and the tholeiitic basalts of the Paraná Basin. In the present study we have performed petrographic and mineral chemistry data to show that all of the study rocks, from the Ybytyruzú Field, are lamproites (leucite lamproite from Yzu-2/Yzu-3/Yzu-7 and sanidine lamproite from Yzu-6).With respect to Yzu-2, Yzu-3 and Yzu-6, the following analyzes show the lamproite character: -phenocrysts/microphenocrysts of: olivine (mg# (Mg/(Mg+Fe)) 0.80-0.85), Al-poor diopside (Al2O3 0.53-2.09% and TiO2 0.65-1.61%), phlogopite/Al-poor-Ti phlogopite (mg# 0.76-0.85, TiO2 5.8-10.2% and Al2O3 12.7-13.9%), Mg-Ti magnetites and leucite (pseudomorphs). -and matrix phases of: Al-poor diopside (Al2O3 0.39-2.46% and TiO2 0.43-1.55%), Al-poor-Ti phlogopite/biotite (mg# 0.57-0.80, TiO2 5.6-10.2% and Al2O3 8.9-12.8%), Mg-Ti magnetites/Ti-magnetites; sanidine (0-4.0% Fe2O3, 0-2.6% BaO and 0-2.5% Na2O). And as accessory phases, ilmenite (0.2-5.7% MgO and 0.3-6.6% MnO), K and Ti-rich Feeckermanite/richterite (1.32-3.6% K2O and 4.7-9.0% TiO2), K-rich Fe-Mg-Mn amphiboles, apatite and quartz (Yzu-6). And so, Ybytyruzú lamproite-like intrusions authenticates the true lamproitic province in Paraguay. III; INTERNATIONAL, 2000 BRAZIL 2000; 3 1ST INTERNATIONAL GEOLOGICAL CONGRESS; ABSTRACTS VOLUME
DS1995-0736
1995
Achache, J.Hamoudi, M., Achache, J., Cohen, Y.Global Magsat anomaly maps at ground levelEarth and Planetary Science Letters, Vol. 133, No. 3-4, July 15, pp. 533-548GlobalGeophysics -Magsat
DS1998-0570
1998
Achache, J.Hamoudi, M., Cohen, Y., Achache, J.Can the thermal thickness of the continental lithosphere be estimated from Magsat data.Tectonophysics, Vol. 284, No. 1-2, Jan. 15, pp. 19-29.MantleGeophysics - MAGSAT., Crustal thickness
DS201112-1026
2011
AchardTallaire, A., Barjon, J., Brinza, O., Achard, Silva, Mille, Issaoui, Tardieu, GicquelDislocations and impurities introduced from etch-pitts at the epitaxial growth resumption of diamond.Diamond and Related Materials, Vol. 20, 7, pp. 875-881.TechnologyDiamond morphology
DS200612-1508
2005
Achard, J.Wang, W., Tallaire, A., Hall, M.S., Moses, T.M., Achard, J., Sussmans, R.S., Gicquel, A.Experimental CVD synthetic diamonds form LIMPH-CNRD France.Gems & Gemology, Vol. 41, 3, Fall, pp. 234244.TechnologySynthetic diamonds
DS200612-0875
2001
Acharya, G.R.Mathew, M.P., Ramachandra, H.M., Gouda, H.C., Singh, R.K., Acharya, G.R., Murthy, C.V.V.S., Rao, K.S.IGRF corrected regional aeromagnetic anomaly map of parts of Peninsular India - potential for mapping and mineral exploration.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 395-405.India, Andhra Pradesh, Karnataka, Tamil Nadu, KeralaGeophysics - magnetics
DS1991-0002
1991
Acharya, S.Acharya, S., Anand, S., Reddy, B.R., Das, R.P.Processing of kimberlite tailings to recover magnesium as MgO or MgSO417th. International Mineral Proceedings Congress, Preprints, pp. 199-209.IndiaMineral processing, Kimberlite tailinsg -magnesiuM.
DS1991-1403
1991
Acharya, S.Reddy, B.R., Acharya, S., Anand, S., Das, R.P.Preparation and characterization of magnesium sulfate heptahydrate From kimberlite tailingsJournal of Thermal Analysis, Vol. 37, No. 5, May pp. 945-951GlobalMining, Mineral processing -tailings
DS1998-0006
1998
Acharyva, S.K.Acharyva, S.K.Break up of East Gondwana Indo-Australian continent: dispersal and accretionary history continental blocks.Journal of African Earth Sciences, Vol. 27, 1A, p. 2. AbstractGondwana, India, AustraliaTectonics, Accretion
DS1989-1371
1989
Acharyya, S.K.Sengupta, S., Acharyya, S.K., Van Den Hul, H.J., Chattopadhyay, B.Geochemistry of volcanic rocks from the Naga Hillsophiolites,northeast India and their inferred tectonic settingJournal of the Geological Society of London, Vol. 146, No. 3, May pp. 491-498IndiaHarzburgite, Tectonics
DS1990-1334
1990
Acharyya, S.K.Sengupta, S., Ray, K.K., Acharyya, S.K., de Smeth, J.B.Nature of ophiolite occurrences along the eastern margin of the Indian plate and their tectonicsignificanceGeology, Vol. 18, No. 5, May pp. 439-442IndiaOphiolites, Tectonics
DS2001-0979
2001
AchauerRitter, J.R.R., Jordan, M., Christensen, U.R., AchauerA mantle plume below the Eifel volcanic fields, GermanyEarth and Planetary Science Letters, Vol. 186, No. 1, pp. 7-14.GlobalTomography, Hot spot
DS1989-0324
1989
Achauer, U.Dahlheim, H.A., Davis, P., Achauer, U.Teleseismic investigation of the East African Rift- KenyaJournal of African Earth Sciences, Vol. 8, No. 2/3/4, pp. 461-470KenyaTectonics, Rifting
DS1991-0603
1991
Achauer, U.Green, W.V., Achauer, U., Meyer, R.P.A three dimensional seismic image of the crust and upper mantle beneath the Kenya riftNature, Vol. 354, No. 6350, November 21, pp. 199-203KenyaMantle, Tectonics -rifting Kenya Rift
DS1992-0004
1992
Achauer, U.Achauer, U.A study of the Kenya rift using delay time tomography analysis and gravitymodelingTectonophysics, Vol. 209, pp. 197-207East Africa, KenyaTectonics, Geophysics -gravity
DS1995-0006
1995
Achauer, U.Achauer, U., Ritter, J.R.R.Upper mantle structure of the Kenya Rift based on joint interpretation of delay time tomography - bouguer dataGeological Society Africa 10th. Conference Oct. Nairobi, pp. 137-8. Abstract.KenyaTectonics, Geophysics -gravity
DS2003-0002
2003
Achchepkov, I.V.Achchepkov, I.V.Empirical garnet thermobarometer for mantle peridotitesGeological Society of America, Annual Meeting Nov. 2-5, Abstracts p.326.Russia, Northwest TerritoriesGeothermometry
DS200412-0002
2003
Achchepkov, I.V.Achchepkov, I.V.Empirical garnet thermobarometer for mantle peridotites.Geological Society of America, Annual Meeting Nov. 2-5, Abstracts p.326.Russia, Canada, Northwest TerritoriesGeothermometry
DS201609-1734
2010
Acker, A.Olivier, D., Bornman, F., Roode, L., Acker, A.Finsch mine treatment plant upgrade project.The 4th Colloquium on Diamonds - source to use held Gabarone March 1-3, 2010, 14p.Africa, South AfricaDeposit - Finsch

Abstract: De Beers' Finsch Mine is situated in the Northern Cape ,province, 170 km northwest of Kimberley. The concentrator facility, designed and constructed by Bateman Engineering, was commissioned in 1967 and upgraded in 1979 using diamond liberation and extraction technology available at the time of design. Since then significant advances in diamond processing and technology have been made and these -have been incorporated into the new main treatment plant and recovery plant flowsheets, making diamond liberation and recovery from the Pre-1979 dumps a viable economic option at Finsch." Significant challenges were experienced as a result of the integration of new technology and its associated infrastructure into an existing plant. Major process flow changes were implemented during the execution phase of the project. The combined effect of these issues resulted in the project being overspent by 25% and the final handover to the Client was some 18 months later than originally planned." The paper highlights some of the difficulties experienced as a result of changes made during the execution phases of the project.
DS1910-0172
1911
Ackere, J. Van.Coppieters, D., Ackere, J. Van.La Regime Minier du Congo BelgeBrussels:, 288P.Democratic Republic of Congo, Central AfricaMining Industry, Kimberley
DS200912-0001
2009
Ackerman, L.Ackerman, L., Walker, R.J., Puchtel, I.S., Pitcher, L., Jelinek, E., Strnad, L.Effects of melt percolation on highly siderophile elements and Os isotopes in subcontinental lithospheric mantle: a study of upper mantle profile central EuropeGeochimica et Cosmochimica Acta, Vol. 73, 8, pp. 2400-2414.Europe, Czech RepublicGeochonology
DS201112-0002
2011
Ackerman, L.Ackerman, L., Spacek, P., Svojtka, M.Pyroxenite xenoliths from Cenozoic alkaline basalts, Bohemian Massif.Goldschmidt Conference 2011, abstract p.406.Europe, Bohemia, PolandBasanites, Foidites
DS201606-1076
2016
Ackerman, L.Ackerman, L., Bizimis, M., Haluzova, E., Slama, J., Svojtka, M.Re-Os and Lu-Hf isotopic constraints on the formation and age of mantle pyroxenites from the Bohemian Massif.Lithos, Vol. 256-257, pp. 197-210.Europe, Czech Republic, AustriaPyroxenite

Abstract: We report on the Lu-Hf and Re-Os isotope systematics of a well-characterized suite of spinel and garnet pyroxenites from the Gföhl Unit of the Bohemian Massif (Czech Republic, Austria). Lu-Hf mineral isochrons of three pyroxenites yield undistinguishable values in the range of 336-338 Ma. Similarly, the slope of Re-Os regression for most samples yields an age of 327 ± 31 Ma. These values overlap previously reported Sm-Nd ages on pyroxenites, eclogites and associated peridotites from the Gföhl Unit, suggesting contemporaneous evolution of all these HT-HP rocks. The whole-rock Hf isotopic compositions are highly variable with initial ?Hf values ranging from ? 6.4 to + 66. Most samples show a negative correlation between bulk rock Sm/Hf and ?Hf and, when taking into account other characteristics (e.g., high 87Sr/86Sr), this may be explained by the presence of recycled oceanic sediments in the source of the pyroxenite parental melts. A pyroxenite from Horní Kounice has decoupled Hf-Nd systematics with highly radiogenic initial ?Hf of + 66 for a given ?Nd of + 7.8. This decoupling is consistent with the presence of a melt derived from a depleted mantle component with high Lu/Hf. Finally, one sample from Be?váry plots close to the MORB field in Hf-Nd isotope space consistent with its previously proposed origin as metamorphosed oceanic gabbro. Some of the websterites and thin-layered pyroxenites have variable, but high Os concentrations paralleled by low initial ?Os. This reflects the interaction of the parental pyroxenitic melts with a depleted peridotite wall rock. In turn, the radiogenic Os isotope compositions observed in most pyroxenite samples is best explained by mixing between unradiogenic Os derived from peridotites and a low-Os sedimentary precursor with highly radiogenic 187Os/188Os. Steep increase of 187Os/188Os at nearly uniform 187Re/188Os found in a few pyroxenites may be connected with the absence of primary sulfides, but the presence of minor late stage sulfide-bearing veinlets likely associated with HT-HP metamorphism at crustal conditions.
DS201707-1300
2017
Ackerman, L.Ackerman, L., Magna, T., Rapprich, V., Upadhyay, D., Kratky, O., Cejkova, B., Erban, V., Kochergina, Y.V., Hrstka, T.Contrasting petrogenesis of spatially related carbonatites from Samalpatti and Sevattur, Tamil Nadu, India.Lithos, Vol. 284-285, pp. 257-275.Indiacarbonatite - Samalpatti, Sevattur

Abstract: Two Neoproterozoic carbonatite suites of spatially related carbonatites and associated silicate alkaline rocks from Sevattur and Samalpatti, south India, have been investigated in terms of petrography, chemistry and radiogenic–stable isotopic compositions in order to provide further constraints on their genesis. The cumulative evidence indicates that the Sevattur suite is derived from an enriched mantle source without significant post-emplacement modifications through crustal contamination and hydrothermal overprint. The stable (C, O) isotopic compositions confirm mantle origin of Sevattur carbonatites with only a modest difference to Paleoproterozoic Hogenakal carbonatite, emplaced in the same tectonic setting. On the contrary, multiple processes have shaped the petrography, chemistry and isotopic systematics of the Samalpatti suite. These include pre-emplacement interaction with the ambient crustal materials with more pronounced signatures of such a process in silicocarbonatites. Calc-silicate marbles present in the Samalpatti area could represent a possible evolved end member due to the inability of common silicate rocks (pyroxenites, granites, diorites) to comply with radiogenic isotopic constraints. In addition, Samalpatti carbonatites show a range of C–O isotopic compositions, and ?13CV-PDB values between + 1.8 and + 4.1‰ found for a sub-suite of Samalpatti carbonatites belong to the highest values ever reported for magmatic carbonates. These heavy C–O isotopic signatures in Samalpatti carbonatites could be indicative of massive hydrothermal interaction with carbonated fluids. Unusual high-Cr silicocarbonatites, discovered at Samalpatti, seek their origin in the reaction of pyroxenites with enriched mantle-derived alkali-CO2-rich melts, as also evidenced by mantle-like O isotopic compositions. Field and petrographic observations as well as isotopic constraints must, however, be combined with the complex chemistry of incompatible trace elements as indicated from their non-uniform systematics in carbonatites and their individual fractions. We emphasise that, beside common carriers of REE like apatite, other phases may be important for incompatible element budgets, such as mckelveyite–(Nd) and kosmochlor, found in these carbonatites. Future targeted studies, including in-situ techniques, could help further constrain temporal and petrologic conditions of formation of Sevattur and Samalpatti carbonatite bodies.
DS201710-2209
2017
Ackerman, L.Ackerman, L., Slama, J., Haluzova, E., Magna, T., Rapprich, V., Kochergin, Y., Upadhyay, D.Hafnium isotope systematics of carbonatites and alkaline silicate rocks from south and west India.Goldschmidt Conference, 1p. AbstractIndiadeposit - Amba Dongar
DS201801-0001
2017
Ackerman, L.Ackerman, L., Magna, T., Rapprich, V., Upadhyay, D., Kratky, O., Cejkova, B., Erban, V., Kochergina, Y.V., Hrstka, T.Contrasting petrogenesis of spatially related carbonatites from Samalpatti and Sevattur, Tamil Nadu, India: insights from trace element and isotopic geochemistry.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 31-33.Indiadeposit - Samalpatti, Sevattur

Abstract: The Tamil Nadu region in southern India hosts several carbonatite bodies (e.g., Hogenakal, Samalpatti, Sevattur, Pakkanadu-Mulakkadu) which are closely associated with alkaline silicate rocks such as syenites, pyroxenites or dunites (e.g, Kumar et al., 1998; Schleicher et al., 1998; Srivastava, 1998). This is in contrast to the carbonatite occurrences in north-western India associated with the Deccan Trap basalts (e.g., Amba Dongar) or Proterozoic Newania dolomitic carbonatites. We have studied two, spatially related, Neoproterozoic carbonatite-silico(carbonatite) suites in association with alkaline silicate rocks (e.g., pyroxenite, gabbro) from Sevattur and Samalpatti in terms of petrography, chemistry and radiogenic-stable isotopic compositions in order to provide constraints on their genesis and evolution. In these two bodies, several different carbonatite types have been reported previously with striking differences in their trace element and isotopic compositions (Srivastava, 1998; Viladkar and Subramanian, 1995; Schleicher et al., 1998; Pandit et al., 2002). Collected data for previously poorly studied calcite carbonatites from the Sevattur representing the first carbonatite magmas on this locality, indicate similar geochemical characteristics to those of dolomitic carbonatites, such as high LREE/HREE ratios, very high Sr and Ba contents, large amounts of apatite and magnetite, identical Sr-Nd-C-O isotopic compositions. Thus, they were derived from an enriched mantle source without significant post-emplacement modifications through crustal contamination and hydrothermal overprint, in agreement with previous studies (e.g., Schleicher et al., 1998). Detailed microprobe analyses revealed that high levels of some incompatible elements (e.g., REE, Y, Sr, Ba) cannot be accounted by matrix calcite hosting only significant amounts of SrO (~0.6-1.2 wt.%). On the other hand, abundant micro- to nano-scale exsolution lamellae and/or inclusions of mckelveyite-(Nd) appear to host a significant fraction of LREE in parallel with apatite. Distribution of Sr is most likely influenced also by common but heterogeneously dispersed barite and strontianite. Newly acquired as well as detailed inspection of available geochemical data permits distinguish two different types of carbonatites in Samalpatti: (1) Type I similar to Sevattur carbonatites in terms of mineralogy, trace element and radiogenic-stable isotopic compositions and (2) Type II with remarkably low concentrations of REE and other incompatible trace elements, more radiogenic Sr isotopic compositions and extremely variable C–O isotopic values. The petrogenesis of the Type II seems to be intimately associated with the presence of silicocarbonatites and abundant silicate mineral domains. Instead of liquid immiscible separation from a silicate magma, elevated SiO2 contents observed in silico-carbonatites may have resulted from the interaction of primary carbonatitic melts and crustal rocks prior to and/or during magma emplacement. Arguments for such hypothesis include variable, but radiogenic Sr isotopic compositions correlated with SiO2 and other lithophile elements (e.g., Ti, Y, Zr, REE). Calc-silicate marbles present in the Samalpatti area could represent a possible evolved crustal end member for such process due to the inability of common silicate rocks (pyroxenites, granites, diorites) to comply with radiogenic isotopic constraints. The wide range of C-O isotopic compositions found in Samalpatti carbonatites belong to the highest values ever reported for magmatic carbonates and can be best explained by massive hydrothermal interaction with carbonated fluids. Unusual high-Cr silicocarbonatites were discovered at Samalpatti forming centimetre to decimetre-sized enclaves enclosed in pyroxenites with sharp contacts at hand specimen scale. Detailed microprobe analyses revealed peculiar chemical compositions of the Mgamphibole with predominantly sodic composition embaying and replacing Na-Cr-rich pyroxene (kosmochlor), accompanied by the common presence of Cr-spinel and titanite. Such association have been reported for hydrous metasomatism by Na-rich carbonatitic melts at upper mantle conditions (Ali and Arai, 2013). However, the mineralogy and the mode of occurrence of Samalpatti Mg–-r-rich silicocarbonatites argue against such origin. We explain the petrogenesis of these rocks through the reaction of pyroxenites with enriched mantle-derived alkali-CO2-rich melts, as also evidenced by mantle-like O and Hf isotopic compositions.
DS201801-0048
2017
Ackerman, L.Polak, L., Ackerman, L., Rapprich, V., Magna, T.Platinum group element and rhenium osmium geochemistry of selected carbonatites from India, USA and East africa.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 22-23.India, United States, Africa, East Africacarbonatites

Abstract: Carbonatites and associated alkaline silicate rocks might have potential economic impact for a large variety of metals such as Cu, Ni, Fe and platinum-group elements (PGE - Os, Ir, Ru, Pd, Pt) as it is demonstrated in South Africa (Phalaborwa; Taylor et al. 2009) or Brazil (Ipanema; Fontana 2006). In addition, determined PGE contents along with Re-Os isotopic compositions may also provide important information about PGE fractionation during the genesis of upper mantle-derived carbonatitic melts and nature of their sources. Nevertheless, the existing PGE data for carbonatites are extremely rare, limited mostly to Chinese localities and they are not paralleled by Re-Os isotopic data (Xu et al. 2008). Therefore, in this study, we present the first complete PGE datasets together with Re-Os determinations for a suite of selected carbonatite bodies worldwide. We have chosen eight carbonatite sites with different alkaline rock association, age and geotectonic position. Among these, the youngest samples are from East African rift system and include Oldoinyo Dili, Tanzania with an age spanning from ~0 to 45 Ma; same as Tororo and Sukulu in Uganda (Woolley and Kjarsgaard 2008). These carbonatites are in association with pyroxenites and nepheline syenites. Another young carbonatitic complex is Amba Dongar in west India with Cretaceous age of ~65 Ma associated with alkaline volcanic rocks such as trachybasalts within Deccan Traps (Sukheswala and Udas 1963). Proterozoic bodies are represented by Iron Hill, USA carbonatites associated with pyroxenite, melitolite and ijolite with age ranging from ~520 to 580 Ma (Nash 1972). These carbonatites are famous for their intensive and varied fenitization. Last and the oldest carbonatites in this study comes from Samalpatti and Sevattur, South India having the age of ~800 Ma (Schleicher et al. 1997) and outcropping as small bodies within alkaline rocks such as pyroxenite, syenite and gabbro. The PGE concentrations and Re-Os isotopic ratios were determined by standard methods consisting of decarbonatization using HCl, decomposition of samples in Carius Tubes in the presence of reverse aqua regia and spikes (isotopic dilution), separation of Os by CHCl3 followed by N-TIMS measurements and Ir, Ru, Pd, Pt, Re isolation by anion exchange chromatography followed by ICP-MS measurements. All analysed carbonatites exhibit extremely low PGE contents (? PGE up to 1 ppb), even in the samples with high S contents (up to 1.5 wt. %). Such values are much lower than other determined so far for upper mantle-derived melts such as basalts, komatiites, etc. (Day et al. 2016). Such signatures indicate very low partitioning of PGE into carbonatitic melts and/or early separation of PGE-bearing fraction. Elements from iridium-group I-PGE; Os, Ir and Ru; mostly < 0.1 ppb) are distinctly lower compared to palladiumgroup elements and Re (PPGE; Pt, Pd, Re; mostly > 0.1 ppb) with some rocks being largely enriched in Re (up to ~6 ppb). Most of the analysed carbonatites exhibit progressive enrichment from Os to Re and consequently, PdN/ReN < 0.1 except south India carbonatites and associated alkaline rocks (> 0.30). Rocks analysed so far for Os have OsN/IrN up to 6.2 that might suggest that the carbonatites might concentrate Os over Ir. The highest HSEtot contents have been found in Mg-Cr-rich silicocarbonatites from South India (up to 40 ppb) and taking into account their only slightly radiogenic 187Os/188Os ratios (0.14-0.57), these rocks represents mixture of CO2-rich alkaline mantle melts and country rocks. Very high concentrations of HSE have been also found in magnetite separated from Fe-carbonatite from Amba Dongar, India (0.2-0.5 ppb of I-PGE and 0.9-9 ppb of P-PGE). The 187Os/188Os ratios determined so far for carbonatites from South India vary from 0.24 to 6.5 and calculated ?Os values range from +100 up to +5000. Such wide range of values suggest extremely heterogenous source of the melts and/or possible contamination by 187Os-rich crustal materials.
DS201910-2241
2019
Ackerman, L.Ackerman, L., Polak, L., Magna, T., Rapprich, V., Jana, D., Upadhyay, D.Highly siderophile element geochemistry and Re-Os isotopic systematics of carbonatites: insights from Tamil Nadu, India.Earth and Planetary Science letters, Vol. 520, pp. 175-187.Indiacarbonatites

Abstract: Carbonatite metasomatism has been widely implicated for worldwide mafic mantle suites but so far, no combined data have been available for highly siderophile element systematics (HSE - Os, Ir, Ru, Pt, Pd, Re) and Re-Os isotopic compositions in carbonatites themselves. We present the first systematic survey of the HSE and Re-Os isotopic compositions in a suite of well-characterized Neoproterozoic carbonatites, silicocarbonatites and associated silicate rocks (pyroxenites, monzogabbros, syenites) from south India in order to place constraints on the HSE systematics in carbonatite magmas, anchoring possible mantle sources of carbonatites and relationship to the ambient crustal lithologies as well as preliminary constraints on carbonatite metasomatism in Earth's mantle. The most plausible explanation for generally low HSE contents in calciocarbonatites from Tamil Nadu (?HSE < 1.22 ppb) involves a low-degree (<1%) partial melting of the mantle source producing sulfur-saturated carbonatitic magmas leaving behind sulfide phases retaining HSE. The new data also indicate a strong FeO control on the distribution of Os and Pt during segregation of carbonatite melt from its enriched mantle source and/or melt differentiation. The combined 187Re/188Os values (from 0.10 to 217), 187Os/188Os ratios (0.186-10.4) and initial ?Os values back-calculated to 800 Ma (from +0.1 to +6052) predict that most Tamil Nadu calciocarbonatites were plausibly derived from a carbonated peridotite source with <10% recycled component. This model would thus provide significant constraints on the origin/source of carbonatites, irrespective of their post-emplacement history. The unusual, volumetrically rare, Mg-Cr-rich silicocarbonatites (?HSE = 14-41 ppb) display almost identical HSE patterns with those of host pyroxenites and predominantly high Pt (up to 38 ppb), the origin of which remains unknown. Positive co-variations between Pt, Pd and Re, and the well-developed positive correlation between Pt and MgO in these Mg-Cr-rich silicocarbonatites argue for a source coming predominantly from the upper mantle. The Re-Os isotopic systematics agree with direct incorporation of enriched mantle-derived material into parental melts but variable incorporation of potassium-rich crustal materials is evidenced by highly positive ?Os800 Ma values for a sub-suite of Mg-Cr-rich silicocarbonatites, indicating intense fenitization. The highly radiogenic Os isotopic compositions of monzogabbros and a syenite argue for their derivation from crustal lithologies with no or only negligible contribution of mantle material. Collectively, low Ir, Ru, Pt and Pd contents found in the Tamil Nadu carbonatites appear to indicate the incapability to significantly modify the total budget of these elements in the Earth's mantle during carbonatite metasomatism. In contrast, very high Re/Os ratios found in some of the analyzed carbonatites, paralleled by extremely radiogenic 187Os/188Os signature, can produce large modification of the Re-Os isotopic composition of mantle peridotites during carbonatite melt percolation when high melt/rock ratios are achieved.
DS201910-2276
2019
Ackerman, L.Krmicek, L., Ackerman, L., Hruby, J., Kynicky, J.The highly siderophile elements and Re Os isotope geochemistry of Variscan lamproites from the Bohemian Massif: implications for regionally dependent metasomatism of orogenic mantle.Chemical Geology, doi: 10.1016/ j.chemgeo .2019.119290 46p. PdfEurope, Czech Republic, Germany, Poland, Austrialamproites

Abstract: Orogenic lamproites represent a group of peralkaline, ultrapotassic and perpotassic mantle-derived igneous rocks that hold the potential to sample components with extreme compositions from highly heterogeneous orogenic mantle. In our pilot study, we present highly siderophile element (HSE) and ReOs isotope systematics of Variscan orogenic lamproites sampled in the territories of the Czech Republic, Austria and Poland, i.e., from the termination of the Moldanubian and Saxo-Thuringian zones of the Bohemian Massif. Orogenic lamproites of the Bohemian Massif are distinguished by variably high contents of SiO2, high Mg# and predominant mineral associations of K-rich amphibole and Fe-rich microcline. The HSE show (i) consistently very low contents in all investigated orogenic lamproites compared to the estimated concentrations in majority of mid-ocean ridge basalts, hotspot-related volcanic rocks (e.g., ocean island basalts, continental flood basalts, komatiites, some intraplate alkaline volcanic rocks such as kimberlites and anorogenic lamproites) and arc lavas, and (ii) marked differences in relative and absolute HSE abundances between the samples from the Moldanubian and Saxo-Thuringian Zone. Such a regional dependence in HSE from mantle-derived melts is exceptional. Orogenic lamproites have highly variable and high initial suprachondritic 187Os/188Os values (up to 0.631) compared with rather chondritic to subchondritic Os isotope values of the young lithospheric mantle below the Bohemian Massif. The highly radiogenic Os isotope component in orogenic lamproites may be derived from preferential melting of metasomatised vein assemblages sitting in depleted peridotite mantle. This process appears to be valid generally in the petrogenesis of orogenic lamproites both from the Bohemian Massif and from the Mediterranean area. As a specific feature of the orogenic lamproites from the Bohemian Massif, originally ultra-depleted mantle component correlative with remnants of the Rheic Ocean lithosphere in the Moldanubian Zone was metasomatised by a mixture of evolved and juvenile material, whereas the lithospheric mantle in the Saxo-Thuringian Zone was enriched through the subduction of evolved crustal material with highly radiogenic Sr isotope signature. As a result, this led to observed unique regionally dependent coupled HSE, RbSr and ReOs isotope systematics.
DS201911-2538
2019
Ackerman, L.Krmicek, L., Ackerman, L.Regionally dependent metasomatism of orogenic mantle revealed by highly siderophile elements and Re-Os isotope geochemistry of Variscan lamproites: a pilot study from the Bohemian Massif.Geologica Carpathica *** In Eng, Vol. 70, pp. 9-11.Europelamproite

Abstract: Orogenic (high-silica) lamproites represent a group of post-collisional mantle-derived igneous rocks that hold the potential to sample components with extreme compositions from highly heterogeneous mantle. In our pilot study, we explore highly siderophile element (HSE) and Re-Os isotope systematics of Variscan orogenic lamproites sampled from the termination of the Moldanubian and Saxo-Thuringian zones of the Bohemian Massif. Orogenic lamproites of the Bohemian Massif are distinguished by variably high contents of SiO2, high Mg# and predominant mineral associations of K-rich amphibole and Fe-rich microcline. The HSE show (i) consistently very low contents in all investigated orogenic lamproites compared to the estimated concentrations in majority of mid- ocean ridge basalts, hotspot-related volcanic rocks and arc lavas, and (ii) marked differences in relative and absolute HSE abundances between the samples from the Moldanubian and Saxo-Thuringian Zone. Such a regional dependence in HSE from mantle-derived melts is exceptional. Orogenic lamproites have highly variable and high initial suprachondritic 187Os/188Os values (up to 0.631) compared with rather chondritic to subchondritic Os isotope values of the young lithospheric mantle below the Bohemian Massif. The highly radiogenic Os isotope component in orogenic lamproites may be derived from preferential melting of metasomatised vein assemblages sitting in depleted peridotite mantle. This process appears to be valid generally in the petrogenesis of orogenic lamproites both from the Bohemian Massif (Variscan lamproites) and from the Mediterranean area (Alpine lamproites). As a specific feature of the orogenic lamproites from the Bohemian Massif, originally ultra-depleted mantle component correlative with remnants of the Rheic Ocean lithosphere in the Moldanubian Zone was metasomatised by a mixture of evolved and juvenile material, whereas the lithospheric mantle in the Saxo-Thuringian Zone was enriched through the subduction of evolved crustal material with highly radiogenic Sr isotope signature. As a result, this led to observed unique regionally dependent coupled HSE, Rb-Sr and Re-Os isotope systematics.
DS202003-0346
2020
Ackerman, L.Krmicek, L., Ackerman, L., Hruby, J., Kynicky, J.The highly siderophile elements and Re-Os isotope geochemistry of Variscan lamproites from the Bohemian Massif: implications for regionally dependent metasomatism of orogenic mantle.Chemical Geology, Vol. 532, 11p. Available pdfEurope, Czech republic, Austria, Polandlamproites

Abstract: Orogenic lamproites represent a group of peralkaline, ultrapotassic and perpotassic mantle-derived igneous rocks that hold the potential to sample components with extreme compositions from highly heterogeneous orogenic mantle. In our pilot study, we present highly siderophile element (HSE) and ReOs isotope systematics of Variscan orogenic lamproites sampled in the territories of the Czech Republic, Austria and Poland, i.e., from the termination of the Moldanubian and Saxo-Thuringian zones of the Bohemian Massif. Orogenic lamproites of the Bohemian Massif are distinguished by variably high contents of SiO2, high Mg# and predominant mineral associations of K-rich amphibole and Fe-rich microcline. The HSE show (i) consistently very low contents in all investigated orogenic lamproites compared to the estimated concentrations in majority of mid-ocean ridge basalts, hotspot-related volcanic rocks (e.g., ocean island basalts, continental flood basalts, komatiites, some intraplate alkaline volcanic rocks such as kimberlites and anorogenic lamproites) and arc lavas, and (ii) marked differences in relative and absolute HSE abundances between the samples from the Moldanubian and Saxo-Thuringian Zone. Such a regional dependence in HSE from mantle-derived melts is exceptional. Orogenic lamproites have highly variable and high initial suprachondritic 187Os/188Os values (up to 0.631) compared with rather chondritic to subchondritic Os isotope values of the young lithospheric mantle below the Bohemian Massif. The highly radiogenic Os isotope component in orogenic lamproites may be derived from preferential melting of metasomatised vein assemblages sitting in depleted peridotite mantle. This process appears to be valid generally in the petrogenesis of orogenic lamproites both from the Bohemian Massif and from the Mediterranean area. As a specific feature of the orogenic lamproites from the Bohemian Massif, originally ultra-depleted mantle component correlative with remnants of the Rheic Ocean lithosphere in the Moldanubian Zone was metasomatised by a mixture of evolved and juvenile material, whereas the lithospheric mantle in the Saxo-Thuringian Zone was enriched through the subduction of evolved crustal material with highly radiogenic Sr isotope signature. As a result, this led to observed unique regionally dependent coupled HSE, RbSr and ReOs isotope systematics.
DS201805-0953
2018
Ackerman, M.Ivanov, A.V., Mukasa, S.B., Kamenetsky, V.S., Ackerman, M., Demonterova, E.I., Pokrovsky, B.G., Vladykin, N.V., Kolesnichenko, M.V., Litasov, K.D., Zedgenizov, D.A.Origin of high-Mg melts by volatile fluxing without significant excess of temperature.Chemical Geology, https://doi.org/ 10.1016/j .chemgeo. 2018.03.11Russiameimechites
DS1975-1226
1979
Ackermand, D.Smith, J.V., Hervig, R.L., Ackermand, D., Dawson, J.B.Potassium, Rubidium, and Barium in Micas from Kimberlite and Peridotitic xenoliths and Implications for Origin of Basaltic Rocks.International Kimberlite Conference SECOND., Vol. 1, PP. 241-251.South Africa, Canada, Ontario, QuebecBasaltic Rocks, Kiberlites, Mica
DS1975-1227
1979
Ackermans, D.Smith, J.V., Hervig, R.L., Ackermans, D., Dawson, J.B.Potassium, Rubidium and Barium in Micas from Kimberlites and Peridotitic xenoliths and Implications for Origin of Basaltic Rocks.Proceedings of Second International Kimberlite Conference, Proceedings Vol. 1, PP. 241-251.South AfricaMineralogy
DS201905-1045
2019
Ackerson, M.Ivanov, A.V., Mukasa, S.B., Kamenetsky, V.S., Ackerson, M., Zedgenizov, D.A.Volatile concentrations in olivine hosted melt inclusions from meimechite and melanephenelinite lavas of the Siberian Trap Large Igneous Province: evidence for flux related high Ti, high Mg magmatism.Chemical Geology, Vol. 483, pp. 442-462.Russiameimechite
DS200512-0376
2005
Acocella, V.Gudmundsson, A., Acocella, V., De Natale, G.The tectonics and physics of volcanoes.Journal of Volcanology and Geothermal Research, Vol. 144, 1-4, pp. 1-5.MantleVolcanoes
DS1960-0771
1967
Acquaah, G.H.M.Acquaah, G.H.M.The Diamond Industry in the Bonsa ValleyB.a. Thesis, University Cape Coast., Ghana, West AfricaProduction, History
DS1993-1223
1993
Acquah, P.C.Peters, J.W., Kesse, G.O., Acquah, P.C.Regional trends in African geology. Proceedings 9th. International Geol. Conference held Accra 1992Geological Society Africa/Ghana, 420pGhana, Uganda, Tanzania, Zaire, Togo, Ivory CoastGold, Tarkian, Birimian, Proterozoic, Mozambique, Book -Table of contents
DS1994-0010
1994
Acquah, P.C.Acquah, P.C.Government environmental regulations and implementation in the miningsectorNatural Resources forum, Vol. 18, No. 3, August pp. 193-206GlobalLegal, laws, Environment
DS200712-0125
2007
Acremont, E.Burov, E.,Guillou Frottier, L., Acremont, E., Le Pourthier, L., Cloetingh, S.Plume head lithosphere interactions near intra continental plate boundaries.Tectonophysics, Vol. 434, 1-4, pp. 15-38.MantleHotspots
DS2002-1193
2002
Acs, P.Ortner, H., Reiter, F., Acs, P.Easy handling of tectonic data: the program Tectonics VB for Mac and Tectonics FP for Windows.Computers and Geosciences, Vol. 28, 10, pp. 1193-1200.GlobalComputers, Program - Tectonics
DS1998-0476
1998
Acton, G.D.Garza, R.S.M., Acton, G.D., Geissman, J.W.Carboniferous through Jurassic paleomagnetic dat a and their bearing on rotation of the Colorado Plateau.Journal of Geophysical Research, Vol. 103, No. B10, Oct. 10, pp. 24179-88.Colorado PlateauGeophysics - paleomagnetics, Tectonics
DS2000-0005
2000
Acton, G.D.Acton, G.D., Tessema, A., Bilham, R.The tectonic and geomagnetic significance of paleomagnetic observations from volcanic rocks centralEarth and Planetary Science Letters, Vol. 180, No. 3-4, pp. 225-42.AfricaTectonics, Volcanics
DS202204-0535
2022
Adachi, T.Sinaice, B.B., Owada, N., Ikeda, H., Toriya, H., Bagai, Z., Shemang, E., Adachi, T., Kawamura, Y.Spectral angle mapping and AI methods applied in automatic identification of placer deposit magnetite using multispectral camera mounted on UAV. *** not specific to diamondsMDPI, Vol. 12, 1., 19p.Globalalluvials

Abstract: The use of drones in mining environments is one way in which data pertaining to the state of a site in various industries can be remotely collected. This paper proposes a combined system that employs a 6-bands multispectral image capturing camera mounted on an Unmanned Aerial Vehicle (UAV) drone, Spectral Angle Mapping (SAM), as well as Artificial Intelligence (AI). Depth possessing multispectral data were captured at different flight elevations. This was in an attempt to find the best elevation where remote identification of magnetite iron sands via the UAV drone specialized in collecting spectral information at a minimum accuracy of +/? 16 nm was possible. Data were analyzed via SAM to deduce the cosine similarity thresholds at each elevation. Using these thresholds, AI algorithms specialized in classifying imagery data were trained and tested to find the best performing model at classifying magnetite iron sand. Considering the post flight logs, the spatial area coverage of 338 m2, a global classification accuracy of 99.7%, as well the per-class precision of 99.4%, the 20 m flight elevation outputs presented the best performance ratios overall. Thus, the positive outputs of this study suggest viability in a variety of mining and mineral engineering practices.
DS1992-0605
1992
Adam, .Green, T.H., Adam, ., Sie, S.H.Trace element partitioning between silicate minerals and carbonatite at 25Kbar and application to mantle MetasomatismMineralogy and Petrology, Vol. 46, No. 3, pp. 179-184MantleSilicates, Metasomatism
DS201711-2497
2017
Adam, C.Adam, C., Caddick, M.J., King, S.D.Pyroxenite causes fat plumes and stagnant slabs.Geophysical Research Letters, DOI: 10.1003/ 2017GL072943Mantleplumes

Abstract: Conventional wisdom holds that there is a change in the pattern of mantle convection between 410 and at 660 km, where structural transformations convert olivine into its high-pressure polymorphs. In this regard, recent tomographic studies have been a complete surprise, revealing (i) rapid broadening of slow seismic anomalies beneath hotspots from hundreds of kilometers wide at shallow depths to 2000-3000 km wide deeper than ~800 km, and (ii) fast seismic anomalies associated with subducted lithosphere that appear to flounder at 800-1000 km. It is difficult to reconcile these observations with the conventional view of a mantle that experiences limited mineralogical change below 660 km. Here we propose that plumes and slabs contain significant proportions of lithologies that experience an entirely different suite of mineral reactions, demonstrating that both subducted basalt and pyroxenite upwelling in plumes experience substantial changes in mineralogy and thus physical properties at ~800 km depth. We show the importance of this for mantle rheology and dynamics and how it can explain hitherto puzzling mantle tomographic results.
DS1991-0602
1991
Adam, J.Green, T.H., Adam, J.Assessment of the garnet-clinopyroxene iron-magnesium exchange thermometer using new experimental dataJournal of Metamorphic Geology, Vol. 9, No. 3, May pp. 341-347AustraliaEclogites, Geothermetry
DS1992-0606
1992
Adam, J.Green, T.H., Adam, J., Sie, S.Trace element partitioning and mantle Metasomatism11th. Australian Geol. Convention Held Ballarat University College, Jan., Listing of papers to be given attempting to get volAustraliaGeochemistry, Mantle
DS1993-0574
1993
Adam, J.Green, T.H., Adam, J., Sie, S.H.Proton microprobe determined trace element partition coefficients betweenpargasite, augite and silicate of carbonatitic meltsEos, Transactions, American Geophysical Union, Vol. 74, No. 16, April 20, supplement abstract p. 340GlobalMineral chemistry, Carbonatite
DS2000-0359
2000
Adam, J.Green, T.H., Blundy, J.D., Adam, J., Yaxley, G.M.SIMS determination of trace element partition coefficients between clinopyroxene and basaltsLithos, Vol. 53, No. 3-4, Sept. 1, pp. 165-87.GlobalPetrology - experimental, Garnet
DS2000-0360
2000
Adam, J.Green, T.H., Blundy, J.D., Adam, J., Yaxley, G.M.SIMS determination of trace element partion coefficients between garnet, clinopyroxene and basalticLithos, Vol. 53, No. 3-4, Sept. pp. 165-87.GlobalPetrology - experimental, Gpa and Temp
DS2001-0004
2001
Adam, J.Adam, J., Green, T.Experimentally determined partition coefficients for minor and trace elements in peridotite minerals...European Journal of Mineralogy, Vol. 13, pp. 815-27.GlobalCarbonatite melt, relevance to natural Carbonatite, Microprobe ICP-MS
DS2001-0409
2001
Adam, J.Green, T., Adam, J.Partition co-efficients - modeling crust-mantle... carbonatite - a popular mantle metasomatic agent.Gemoc Annual Report 2000, p. 34-5.MantleCarbonatite, Geochemistry
DS200612-0001
2006
Adam, J.Adam, J., Green, T.Trace element partitioning between mica and amphibole bearing garnet lherzolite and hydrous basanitic melt: 1. experimental results and the investigation controlsContributions to Mineralogy and Petrology, Online, availableAustralia, TasmaniaPartitioning behaviour, melting
DS200612-0495
2006
Adam, J.Green, T.H., Hauri, E.H., Gaetani, G.A., Adam, J.New calculations on water storage in the upper mantle, and implications for mantle melting models.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 215, abstract only.MantleWater
DS201212-0002
2012
Adam, J.Adam, J., Oberti, R., Camara, F., Green, T.H., Rushmer, T.The effect of water on equilibrium relations between clinopyroxenes and basanitic magmas: tracing water and non- volatile incompatible elements in the Earth's mantle.emc2012 @ uni-frankfurt.de, 1p. AbstractMantleMelting
DS201412-0864
2013
Adam, J.Sodoudi, F., Yuan, X., Kind, R., Lebedev, S., Adam, J., et al.Seismic evidence for stratification in composition and anisotropic fabric within the thick lithosphere of Kalahari craton.Geochemistry, Geophysics, Geosystems: G3, Vol. 14, 12, pp. 5393-5412.Africa, South AfricaGeophysics - seismics
DS201605-0808
2016
Adam, J.Adam, J., Turner, M., Hauri, E.H., Turner, S.Crystal/melt partitioning of water and other volatiles during the near-solidus melting of mantle peridotite: comparisons with non-volatile incompatible elements and implications for the generation of intraplate magmatism.American Mineralogist, Vol. 101, pp. 876-888.MantleMagmatism - basanite, melting

Abstract: Concentrations of H2O, F, Cl, C, P, and S have been measured by secondary ion mass spectrometry (SIMS) in experimentally produced peridotite phases (including clinopyroxene, orthopyroxene, olivine, garnet, amphibole, and mica) and coexisting basanitic glasses. Because only two experiments produced glasses on quenching (with the melt phase in others reverting to felt-like crystallite masses) H2O concentrations in melts were also separately determined from mass-balance relationships and by assuming constant H2O/La in melts and starting materials. The resulting values were used to calculate mineral/melt partition coefficients (D values) for H2O [where DH2Ocrystal/melt = (mass fraction of H2O in crystal)/(mass fraction of H2O in melt)] for conditions of 1025-1190 °C and 1.0-3.5 GPa. These gave 0.0064-0.0164 for clinopyroxene, 0.0046-0.0142 for orthopyroxene, 0.0015-0.0016 for olivine, and 0.0016-0.0022 for garnet. Although less information was obtained for the other volatiles, F was found to be significantly more compatible than H2O during peridotite melting, whereas Cl is significantly less compatible. S also has small but appreciable solubilities in amphiboles and micas, but not in pyroxenes or olivine. The solubility of C in silicate minerals appears to be negligible, although C was present in coexisting melts (~0.5 wt% as CO2) and as residual graphite during experiments. The D values for H2O in clinopyroxene and orthopyroxene are positively correlated with ivAl but negatively correlated with the H2O concentrations of melts (when considered as wt%). These relationships are consistent with the broad trends of previously published partitioning data. Although some of the concentration dependence can be related to cross-correlation between ivAl in pyroxenes and H2O concentrations in melts (via the latter’s control of liquidus temperatures) this relationship is too inconsistent to be a complete explanation. A concentration dependence for DH2Omineral/melt can also be independently predicted from speciation models for H2O in silicate melts. Thus it is likely that DH2Opyx/melt is influenced by both ivAl and the absolute concentration of H2O in melts. DH2O/DCe for clinopyroxene is inversely correlated with M2 site radii. Because the latter decrease with increasing pressure and temperature, relatively hot and/or deeply derived melts should be enriched in Ce relative to H2O when compared to melts from cooler and shallower mantle sources. Conversely, melts from H2O-rich settings (e.g., subduction zones) should have higher H2O/Ce than their source rocks. When combined with previously obtained partitioning data for non-volatile elements (from the same experiments), our data are consistent with the enrichment of intraplate basalt sources in both volatile and non-volatile incompatible elements by small-degree melts derived from local mid-ocean ridge basalt sources. In this way, volatiles can be seen to play an active role (via their promotion of partial-melting and metasomatic processes) in the auto-regulation of incompatible element concentrations in the depleted upper mantle.
DS201808-1783
2018
Adam, J.Ravenna, M., Lebedev, S., Fullea, J., Adam, J.Shear wave velocity structure of Southern Africa's lithosphere: variations in the thickness and composition of cratons and their effect on topography.Geochemistry, Geophysics, Geosystems, Vol. 19, 5, pp. 1499-1518.Africa, South Africacraton

Abstract: Cratons, the ancient cores of continents, have an unusually thick lithosphere (the tectonic plate beneath them). At least ?200 km thick, it has a highly anomalous composition, making it less dense than the surrounding mantle. Cratonic lithosphere can thus be cooled to much lower temperatures than elsewhere. Variations in this delicate buoyancy balance probably give rise to variations in the surface elevation across the Earth's stable continents. Lithospheric thickness and composition are key parameters, but both are notoriously difficult to determine. Here we use very accurate measurements of seismic surface?wave velocities and determine deep structure beneath cratons in southern Africa. We discover an unexpectedly strong, gradual thickening of the lithosphere from the central Kaapvaal Craton to the neighboring Limpopo Belt (from 200 to 300 km thick). Curiously, surface elevation decreases monotonically with increasing lithospheric thickness. This demonstrates the effect of the deep lithosphere on topography and gives us new information on the composition of the deepest parts of lithosphere.
DS201810-2385
2018
Adam, J.Tuck-Martin, A., Adam, J., Eagles, G.New plate kinematic model and tectono-stratigraphic history of the East African and West Madagascar margins.Basin Research, doi:10.1111/bre.12294 23p.Africa, Madagascartectonics

Abstract: The continental margins of East Africa and West Madagascar are a frontier for hydrocarbon exploration. However, the links between the regional tectonic history of sedimentary basins and margin evolution are relatively poorly understood. We use a plate kinematic model built by joint inversion of seafloor spreading data as a starting point to analyse the evolution of conjugate margin segments and corresponding sedimentary basins. By correlating megasequences in the basins to the plate model we produce a margin?scale tectono?stratigraphic framework comprising four phases of tectonic development. During Phase 1 (183-133 Ma) Madagascar/India/Antarctica separated from Africa, first by rifting and later, after breakup (at ca. 170-165 Ma), by seafloor spreading in the West Somali and Mozambique basins and dextral strike?slip movement on the Davie Fracture Zone. Mixed continental/marine syn?rift megasequences were deposited in rift basins followed by shallow?marine early postrift sequences. In Phase 2 (133-89 Ma) spreading ceased in the West Somali basin and Madagascar became fixed to the African plate. However, spreading continued between the African and Antarctic plates and deposition of the early postrift megasequence continued. The onset of spreading on the Mascarene Ridge separated India from Madagascar in Phase 3 (89-60 Ma). Phase 3 was characterized by the onset of deposition of the late postrift megasequence with continued deep marine sedimentation. At the onset of Phase 4 (60 Ma onward) spreading on the Mascarene ridge ceased and the Carlsberg Ridge propagated south to form the Central Indian Ridge, separating India from the Seychelles and the Mascarene Plateau. Late postrift deposition continued until a major unconformity linked to the development of the East African Rift System marked the change to deposition of the modern margin megasequence.
DS202108-1315
2021
Adam, J.Wouters, M.C., Perez-Diaz, L., Tuck-Martin, A., Eagles, G., Adam, J., Grovers, R.Dynamics of the African plate 75Ma: from plate kinematic reconstructions to interplate paleo-stresses,Tectonics, e2020TC006355Africageodynamics

Abstract: Plate reconstruction studies show that the Neotethys Ocean was closing due to the convergence of Africa and Eurasia toward the end of the Cretaceous. The period around 75 Ma reflects the onset of continental collision between the two plates as convergence continued to be taken up mostly by subduction of the Neotethys slab beneath Eurasia. The Owen transform plate boundary in the northeast accommodated the fast northward motion of the Indian plate relative to the African plate. The rest of the plate was surrounded by mid-ocean ridges. Africa was experiencing continent-wide rifting related to northeast-southwest extension. We aim to quantify the forces and paleostresses that may have driven this continental extension. We use the latest plate kinematic reconstructions in a grid search to estimate horizontal gravitational stresses (HGSs), plate boundary forces, and the plate's interaction with the asthenosphere. The contribution of dynamic topography to HGSs is based on recent mantle convection studies. We model intraplate stresses and compare them with the strain observations. The fit to observations favors models where dynamic topography amplitudes are smaller than 300 m. The results also indicate that the net pull transmitted from slab to the surface African plate was low. To put this into context, we notice that available tectonic reconstructions show fragmented subduction zones and various colliding micro-continents along the northern margin of the African plate around this time. We therefore interpret a low net pull as resulting from either a small average slab length or from the micro-continents' resistance to subduction.
DS201312-0529
2013
Adam, J.M-C.Lebedev, S., Adam, J.M-C., Meier, T.Mapping the Moho with seismic surface waves: a review, resolution analysis and recommended inversion strategies.Tectonophysics, Vol. 609, pp. 377-394.MantleMohorovic discontinuity
DS1992-0005
1992
Adamia, S.Adamia, S., et al.Geology of the Republic of Georgia: a reviewInternational Geology Review, Vol. 34, No. 5, pp. 447-476.Georgia, RussiaGeneral geology - not specific to diamonds, Gondwana
DS1992-0006
1992
Adamia, S.Adamia, S., Akhvlediani, K.T., Kilasonia, V.M., Nairn, A.E.M.Geology map of the Dubawnt Lake area, Northwest TerritoriesInternational Geology Review, Vol. 34, No. 5, May pp. 447-476Russia, GeorgiaGeology, Review
DS200612-1169
2006
Adamo, I.Rolandi, V., Brajkovic, A., Adamo, I., Landonio, M.Diamonds from Udachnaya pipe, Yakutia. Their morphology, optical and Raman characteristics, FTIR and CL features.Australian Gemmologist, Vol. 22, no. 9 Jan-Mar, pp.RussiaDiamond morphology
DS2000-0256
2000
AdamsEaton, D.W., Atkinson, Ferguson, Adams, Asudeh, JonesPOLARIS: an in depth look at Canada's subcontinental mantle and earthquakehazards.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 4p. abstract.Ontario, Northwest TerritoriesGeophysics - seismics, lithospheric, Structure - Phanerozoic
DS200512-0113
2005
AdamsBrenker, F.E., Vincze, L., Velemans, Nasdala, Stachel, Vollmer, Kersten, Somogyi, Adams, Joswig, HarrisDetection of a Ca rich lithology in the Earth's deep ( >300km) convecting mantle.Earth and Planetary Science Letters, Vol. 236, 3-4, pp. 579-587.Africa, GuineaKankan, diamond inclusions, spectroscopy
DS201112-0003
2011
Adams, A.Adams, A., Nyblade, A.Shear wave velocity structure of the southern African upper mantle with implications for the uplift of southern Africa.Geophysical Journal International, Vol. 186, 2, pp. 808-824,AfricaGeophysics - seismics
DS201112-0004
2011
Adams, A.Adams, A., Nyblade, A.Shear wave velocity structure of the southern African upper mantle with implications for the uplift of southern Africa.Geophysical Journal International, in press available,AfricaGeophysics - seismics
DS201212-0003
2012
Adams, A.Adams, A., Nyblade, A., Weeraratne, D.Upper mantle shear wave velocity structure beneath the East African Plateau: evidence for a deep plateauwide low velocity anomaly.Geophysical Journal International, Vol. 189, 1, pp. 123-142.AfricaGeophysics - seismics
DS201312-0662
2013
Adams, A.Odonnell, J.P., Adams, A., Nyblade, A.A., Mulibo, G.D., Tugume, F.The uppermost mantle shear wave velocty structure of eastern Africa from Rayleigh wave tomography: constraints on rift evolution.Geophysical Journal International, Vol. 194, 2, pp. 961-978.AfricaGeophysics - seismics
DS1998-0007
1998
Adams, A.E.Adams, A.E., MacKenzie, W.S.A colour atlas of carbonate sediments and rocks under the microscopeOxford University of Press, 192p. approx. $ 90.00GlobalBook - ad, Atlas - carbonate sediments
DS1992-0979
1992
Adams, C.Maclean, D., Adams, C.Diamonds in Canada odds of finding a mine are long, but favourable forWood Gundy Investment Research, June 24, 5pCanada, Northwest TerritoriesNews item, Promotional literature -background
DS1997-0007
1997
Adams, C.Adams, C.Financing exploration through Canadian markets: an updateAssaying and Reporting Conference Nov. 10-11, 1997 Singapore, 34 slide copies onlyCanadaSampling, assaying, ore reserves, discoveries, Geostatistics, gold, investment, economics, legal
DS201910-2254
2019
Adams, C.Dentith, M., Enkin, R.J., Morris, W., Adams, C., Bourne, B.Petrophysics and mineral exploration: a workflow for data analysis and a new interpretation framework. ( Not specific to diamonds)Geophysical Prospecting, htpps://doi.org/10.1111/1365-2478.12882Globalgeophysics - seismic

Abstract: As mineral exploration seeks deeper targets there will be a greater reliance on geophysical data and a better understanding of the geological meaning of the responses will be required, and this must be achieved with less geological control from drilling. Also, exploring based on the mineral system concept requires particular understanding of geophysical responses associated with altered rocks. Where petrophysical datasets of adequate sample size and measurement quality are available, physical properties show complex variations, reflecting the combined effects of various geological processes. Large datasets, analysed as populations, are required to understand the variations. We recommend the display of petrophysical data as frequency histograms as the nature of the data distribution is easily seen with this form of display. A petrophysical data set commonly contains a combination of overlapping sub?populations, influenced by different geological factors. To understand the geological controls on physical properties in hard rock environments it is necessary to analyse the petrophysical data not only in terms of the properties of different rock types. It is also necessary to consider the effects of processes such as alteration, weathering, metamorphism, and strain, and variables such as porosity and stratigraphy. To address this complexity requires that much more supporting geological information be acquired than is current practice. The widespread availability of field portable instruments means quantitative geochemical and mineralogical data can now be readily acquired, making it unnecessary to rely primarily on categorical rock classification schemes. The petrophysical data can be combined with geochemical, petrological and mineralogical data to derive explanations for observed physical property variations based not only on rigorous rock classification methods, but also in combination with quantitative estimates of alteration and weathering. To understand how geological processes will affect different physical properties it is useful to define three end?member forms of behaviour. Bulk behaviour depends on the physical properties of the dominant mineral components. Density and, to a lesser extent, seismic velocity show such behaviour. Grain and texture behaviour occur when minor components of the rock are the dominate controls on its physical properties. Grain size and shape control grain properties, and for texture properties the relative positions of these grains are also important. Magnetic and electrical properties behave in this fashion. Thinking in terms of how geological processes change the key characteristics of the major and minor mineralogical components allows the resulting changes in physical properties to be understood and anticipated.
DS201602-0189
2016
Adams, C.J.Augstsson, C., Wilner, A.P., Rusing, T., Niemeyer, H., Gerdes, A., Adams, C.J., Miller, H.The crustal evolution of South America from a zircon Hf-isotope perspective.Terra Nova, In press availableSouth AmericaGeochronology

Abstract: Hf-isotope data of greater than 1100 detrital zircon grains from the Palaeozoic, south-central Andean Gondwana margin record the complete crustal evolution of South America, which was the predominant source. The oldest grains, with crustal residence ages of 3.8-4.0 Ga, are consistent with complete recycling of existing continental crust around 4 Ga. We confirm three major Archaean, Palaeoproterozoic (Transamazonian) and late Mesoproterozoic to early Neoproterozoic crust-addition phases as well as six igneous phases during Proterozoic to Palaeozoic time involving mixing of juvenile and crustally reworked material. A late Mesoproterozoic to early Neoproterozoic, Grenville-age igneous belt can be postulated along the palaeo-margin of South America. This belt was the basement for later magmatic arcs and accreted allochthonous microcontinents as recorded by similar crustal residence ages. Crustal reworking likely dominated over juvenile addition during the Palaeozoic era, and Proterozoic and Archaean zircons were mainly crustally reworked from the eroding, thickened Ordovician Famatinian arc.
DS201604-0591
2016
Adams, C.J.Augustsson, C., Willner, A.P., Rusing, T., Niemeyer, H., Gerdes, A., Adams, C.J., Miller, H.The crustal evolution of South America from a zircon Hf-isotope perspective.Terra Nova, Vol. 28, 2, pp. 128-137.South AmericaTectonics

Abstract: Hf-isotope data of >1100 detrital zircon grains from the Palaeozoic, south-central Andean Gondwana margin record the complete crustal evolution of South America, which was the predominant source. The oldest grains, with crustal residence ages of 3.8-4.0 Ga, are consistent with complete recycling of existing continental crust around 4 Ga. We confirm three major Archaean, Palaeoproterozoic (Transamazonian) and late Mesoproterozoic to early Neoproterozoic crust-addition phases as well as six igneous phases during Proterozoic to Palaeozoic time involving mixing of juvenile and crustally reworked material. A late Mesoproterozoic to early Neoproterozoic, Grenville-age igneous belt can be postulated along the palaeo-margin of South America. This belt was the basement for later magmatic arcs and accreted allochthonous microcontinents as recorded by similar crustal residence ages. Crustal reworking likely dominated over juvenile addition during the Palaeozoic era, and Proterozoic and Archaean zircon was mainly crustally reworked from the eroding, thickened Ordovician Famatinian arc.
DS201412-0209
2014
Adams, D.Downes, P.J., Demeny, A., Czuppon, G., Jacques, A.L., Verrall, M., Sweetapple, M., Adams, D., McNaughton, N.J., Gwalani, L.G., Griffin, B.J.Stable H-C-O isotope and trace element geochemistry of the Cummins Range carbonatite complex, Kimberley region Western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regions.Mineralium Deposita, in press available 28p.AustraliaCarbonatite
DS201412-0210
2014
Adams, D.Downes, P.J., Demeny, A., Czuppon, G., Jaques, A.L., Verrall, M., Sweetapple, M., Adams, D., McNaughton, N.J., Gwalani, L.G., Griffin, B.J.Stable H-C-O isotope and trace element geochemistry of the Cummins Range carbonatite complex, Kimberley region western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regions.Mineralium Deposita, Vol. 49, p. 905-932.AustraliaCarbonatite
DS201603-0381
2016
Adams, D.Griffin, W.L., Gain, S.E.M., Adams, D., Huang, J-X., Saunders, M.,Toledo, V., Pearson, N.J., O'Reilly, S.Y.Heaven on Earth: tistarite ( Ti203) and other nebular phases in corundum aggregates from Mt. Carmel volcanic rocks.Israel Geological Society, pp. 85-86. abstractEurope, IsraelMoissanite

Abstract: This ending talk, focused on the ongoing cooperative research of Prof. Griffin and his team at Macquarie University and Shefa Yamim, since January 2014, highlighting unique corundum species characteristics. Preliminary results of this research were presented in the IGS Annual Meeting of 2015, whereas this year Prof. Griffin has shared innovative findings only microscopically tracked within titanium-rich corundum aggregates. One of the more abundant minerals is Tistarite (Ti2O3), previously known only as a single grain in a primitive type of meteorite (!). An article has been submitted to a scientific journal detailing this first terrestrial occurrence. Several other minerals are common in meteorites, but unknown or extremely rare on Earth. About half of these minerals are unknown to science, and will be described as new minerals in the scientific literature. The first of these is a Titanium-Aluminium-Zirconium oxide, informally known as TAZ; it will be submitted to the International Mineralogical Association for recognition as a new mineral, ShefaTAZite. Using state of the art technologies such as Thermal Ionisation Mass Spectrometry (TIMS) and Electron Microscopy Facility (EMF) that has three scanning electron microscopes, all with EBSD capability, and a transmission electron microscope - Prof. Griffin revealed spectacular imagery of minerals and rare compounds associated with titanium rich corundum aggregates.
DS201603-0382
2016
Adams, D.Griffin, W.L., Gain, S.E.M., Adams, D., Toledo, V., Pearson, N.J., O'Reilly, S.Y.Deep-Earth methane, mantle dynamics and mineral exploration: insights from northern Israel, southern Tibet and Kamchatka.Israel Geological Society, pp. 87-88. abstractEurope, Israel, TibetMoissanite
DS1992-0007
1992
Adams, D.C.Adams, D.C., Keller, G.R.A geophysical investigation of possible southern extensions of The midcontinent rift systemGeological Society of America (GSA) Abstracts with programs, 1992 Annual, Vol. 24, No. 7, abstract p. A329MidcontinentGeophysics, Tectonic, rifting
DS1992-0835
1992
Adams, D.C.Keller, G.R., Adams, D.C.Thoughts on the nature and extent of Keweenawan rifting in North America based on recent results in other rift systemsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 319MidcontinentKeweenawan Rift, Tectonics
DS1994-0011
1994
Adams, D.C.Adams, D.C., Keller, G.R.Possible extension of the Midcontinent Rift in West Texas and eastern NewMexico.Canadian Journal of Earth Sciences, Vol. 31, No. 4, April pp. 709-720.Texas, New MexicoTectonics, Midcontinent Rift
DS201610-1865
2016
Adams, D.T.Griffin, W.L., Gain, S.E.M., Adams, D.T., Huang, J-X., Saunders, M., Toledo, V., Pearson, N.J., O'Reilly, S.Y.First terrestrial occurrence of tistarite ( Ti2O3): ultra-low oxygen fugacity in the upper mantle beneath Mount Carmel, Israel.Geology, Vol. 44, 10, pp. 815-818.Europe, IsraelMoissanite

Abstract: The minimum oxygen fugacity (fO2) of Earth's upper mantle probably is controlled by metal saturation, as defined by the iron-wüstite (IW) buffer reaction (FeO ? Fe + O). However, the widespread occurrence of moissanite (SiC) in kimberlites, and a suite of super-reduced minerals (SiC, alloys, native elements) in peridotites in Tibet and the Polar Urals (Russia), suggest that more reducing conditions (fO2 = 6-8 log units below IW) must occur locally in the mantle. We describe pockets of melt trapped in aggregates of corundum crystals ejected from Cretaceous volcanoes in northern Israel which contain high-temperature mineral assemblages requiring extremely low fO2 (IW < -10). One abundant phase is tistarite (Ti2O3), previously known as a single grain in the Allende carbonaceous chondrite (Mexico) and believed to have formed during the early evolution of the solar nebula. It is associated with other reduced phases usually found in meteorites. The development of super-reducing conditions in Earth's upper mantle may reflect the introduction of CH4 + H2 fluids from the deep mantle, specifically related to deep-seated volcanic plumbing systems at plate boundaries.
DS1860-0722
1892
Adams, F.D.Adams, F.D.On a Melilite Bearing Rock (alnoite) from St. Anne de Bellevue, Near Montreal.American Journal of Science, SER. 3, Vol. 43, PP. 269-279.Canada, QuebecMelilite, Alnoite
DS1900-0140
1903
Adams, F.D.Adams, F.D.The Montregian Hills- a Canadian Petrographic ProvinceJournal of GEOLOGY, Vol. 11, PP. 239-282.Canada, QuebecAlkaline rocks
DS1986-0001
1986
Adams, G.E.Adams, G.E., Bishop, F.C.The olivine-clinopyroxene geobarometer experimental results in the CEMS system and application to natural lherzolitesGeological Society of America (GSA) Abstract Volume, Vol. 18, No. 6, p. 522. (abstract.)GlobalLherzolite, Geobarometry, Thermobarome
DS1997-0167
1997
Adams, G.W.Carlson, S.M., Adams, G.W.The Diamondiferous SIX-PAK ultramafic lamprophyre diatreme, Kenosha, Wisconsin, USAInstitute Lake Superior Geology, 2p.WisconsinLamprophyre, Diamonds
DS1859-0072
1842
Adams, J.Adams, J.Memo on the Geology of Bundelk hand and JubbalporeAsiatic Soc. Bengal Journal, Vol. 11, PP. 392-411.IndiaRegional Geology
DS1983-0232
1983
Adams, J.Forsyth, D., Morel, P., Hasegawa, H., Wetmiller, R., Adams, J.Comparative Study of the Geophysical and Geological InformatAtomic Energy of Canada Research Limited., No. TR-238, 52P.Canada, OntarioTectonics
DS1989-0005
1989
Adams, J.Adams, J., Basham, P.The seismicity and seismotectonics of Canada east of the CordilleraGeoscience Canada, Vol. 16, No. 1, March pp. 3-16Appalachia, MidcontinentGeophysics, Seismics
DS1989-0547
1989
Adams, J.Grieve, R.A.F., Adams, J., Goodacre, A.K., Nevitt, L., TeskeyThe Canadian geophysical atlasGeological Society of Canada (GSC) Forum 1989, P. 12 abstractOntarioGeophysical atlas
DS1989-1687
1989
Adams, J.Zoback, M.L., Zoback, M.D., Adams, J., Assumpcao, M., et al.Global patterns of tectonic stressNature, Vol. 341, No. 6240, September 28, pp. 291-298GlobalTectonics, Rift
DS1993-0008
1993
Adams, J.Adams, J., Ckague, J.J.Neotectonics and large scale geomorphology of CanadaCanadian Journal of Earth Sciences, Vol. 17, No. 2, pp. 248-63.CanadaGeomorphology, Gophysics - seismics
DS1993-0009
1993
Adams, J.Adams, J., Clague, J.J.Neotectonics and large scale geomorphology of CanadaPhysical Georgraphy, Vol. 17, No. 2, pp.248-264CanadaGeomorphology, Tectonics, structure
DS1996-0004
1996
Adams, J.Adams, J.Paleoseismology in Canada: a dozen years of progressJournal of Geophysical Research, Vol. 101, No. 3, March 10, pp. 6193-6208.CanadaGeophysics -seismics, History
DS200512-0002
2005
Adams, M.G.Adams, M.G., Lentz, D.R., Shaw, C.S., Williams, P.F., Archibald, D.A., Cousens, B.Eocene shoshonitic mafic dykes intruding the Monashee Complex, British Columbia: a petrogenetic relationship with the Kam loops Group volcanic sequence.Canadian Journal of Earth Sciences, Vol. 42, 1, pp. 11-24.Canada, British ColumbiaShoshonite
DS201012-0769
2010
Adams, N.Sullivan, D., Adams, N.Digging in: recent developments on conflict minerals.enoughproject.org, Jan. 14p.Africa, Democratic Republic of CongoNews item - legal
DS1981-0001
1981
Adams, R.C.G.Adams, R.C.G., Bielicki, T.A., Lang, A.R.Correlation of Electrostatic Charging Patterns with Internal Structure in Diamonds.Journal of MATERIALS SCIENCE., Vol. 16, No. 9, PP. 2369-2380.GlobalDiamond Morphology
DS200712-0002
2007
Adams, S.Adams, S.King of Bling: how a poor boy from London became diamond merchant to the world's super wealthy.Forbes.com, Vol. 180, 3, August 13, p. 84.Global, Europe, EnglandNews item - Laurence Graff
DS1975-0219
1976
Adams, W.T.Adams, W.T.Gem Stones; United States Bureau of Mines, 1976United States Bureau of Mines MINERALS YEARBOOK, Vol. 1, PP. 1-10.United States, Canada, Global, South AfricaBlank
DS1975-0904
1979
Adams, W.T.Adams, W.T.Diamond-industrialUnited States Bureau of Mines MINERAL COMMODITY PROFILE., JUNE 16P.United States, GlobalProduction, Supply, Exports, Resources, Reserves
DS1900-0606
1908
Adamson, F.Adamson, F.New Patent for Improved Diamond WasherSouth African Mining Journal, Vol. 6, PT. 2, SEPT. 12TH. P. 793.Africa, South AfricaMining Methods
DS1950-0442
1959
Adamson, R.J.Adamson, R.J.Some Account of the Diamond Mining Practices in Southern Africa.South African Institute of Mining and Metallurgy. Journal, Vol. 60, No. 1, PP. 23-50.South Africa, Southwest Africa, NamibiaMining Methods, Diamond Recovery, Kimberlite Pipes
DS1960-0001
1960
Adamson, R.J.Adamson, R.J.Diamond Recovery in Southern AfricaSouth African Institute of Mining and Metallurgy. Journal, Vol. 61, SEPT., PP.South AfricaMining Methods, Diamond Recovery, Kimberlite Pipes
DS1960-0315
1963
Adamson, R.J.Adamson, R.J., Hodgson, H.F.The Re-treatment Plant at Premier Diamond MineSouth African Institute of Mining and Metallurgy. Journal, Vol. 64, SEPT. PP. 45-67.South AfricaDiamond Mining Recovery, Kimberlite Pipes
DS1920-0356
1928
Adar, D.A.Adar, D.A.Diamonds; Lippincott's Magazine, 1928Lippincott's Magazine., Vol. 47, P. 525.South AfricaCurrent Activities
DS200812-0193
2008
Adar, F.Chakhmouradian, A.R., Cooper, M.A., Medici, L., Hawthorne, F.C., Adar, F.Fluorine rich hibschite from silicocarbonatite, AfrikAnd a Complex, Russia: crystal chemistry and conditions of crystallization.Canadian Mineralogist, Vol. 46, 4, August pp.RussiaCarbonatite
DS1980-0001
1980
Adcock, G.Adcock, G.Diamonds: a New Appraisal for Estate PlannersTrusts And Estates, Vol. 119, No. 1, PP. 52-55.GlobalInvestment
DS201012-0569
2010
Adcock, S.W.Paulen, R.C., Adcock, S.W., Spirito, W.A., Chorlton, L.B., McClenaghan, M.B., Oviatt, Budulan, RobinsonsInnovative methods to search, download and display indicator mineral data: a new Tri-Territorial Indicator Mineral Database.38th. Geoscience Forum Northwest Territories, Abstract pp. 75-76.Canada, Northwest TerritoriesGEM database
DS201312-0875
2013
Adcock, S.W.Spirito, W.A., Adcock, S.W., Paulen, R.C.Managing geochemical data: challenges and best practices.GSC Open file 7374 Ftp2.cits.rncan.gc.ca, pp. 21-26.TechnologyGeochemistry
DS200412-1664
2004
Addad, A.Ricolleau, A., Perrillat, J.P., Fiquet, G., Menguy, N., Daniel, I., Addad, A., Vanni, C.The fate of subducted basaltic crust in the Earth's lower mantle: an experimental petrological study.Lithos, ABSTRACTS only, Vol. 73, p. S93. abstractMantleSubduction
DS200812-0069
2008
Addad, A.Auzende, A-L., Badro, J., Ryerson, F.J., Weber, P.K., Fallon, S.J., Addad, A., Siebert, J., Fiquet, G.Element partitioning between magnesium silicate perovskite and ferropericlase: new insights into bulk lower mantle geochemistry.Earth and Planetary Science Letters, Vol. 269, 1-2, May 15, pp. 164-174.MantleGeochemistry
DS200812-0892
2008
Addison, R.Petterson, M.G., Toila, D., Cronin, S.J., Addison, R.Communicating geoscience to indigenous people: examples from the Solomon Islands.Geological Society of London Special Publication, No. 305, pp. 141-161.Asia, Solomon IslandsAboriginal
DS201212-0602
2012
Addoum, B.Roure, F., Casero, P., Addoum, B.Alpine inversion of the North Africa margin and delamination of its continental lithosphere.Tectonics, Vol. 31, 3, TC3006AfricaTectonics
DS200912-0604
2009
Adel, S.H.Purohit, M.K., Kathal, P.K., Adel, S.H.Discovery of micro-diamonds in beach sands of the Negapattinam and Vedaranniyam beaches, southern east coast of India.Current Science, Vol. 98, 6, March 25, pp.767-8.IndiaMicrodiamonds
DS2002-0008
2002
Adeoye, A.Adeoye, A.Remote sensing analysis of basement complex of southwestern Nigeria using radar imagery.16th. International Conference On Basement Tectonics '02, Abstracts, 2p., 2p.NigeriaStructure - lineaments
DS201012-0475
2010
Ader, M.Mata, J., Moreira, M., Doucelance, R., Ader, M., Silva, L.C.Noble gas and carbon isotopic signatures of Cape Verde oceanic carbonatites: implications for carbon provenance.Earth and Planetary Science Letters, Vol. 291, 1-4, pp. 70-83.Europe, Cape Verde IslandsCarbonatite
DS200612-0002
2005
Adetoro, D.O.Adetoro, D.O.Examining mediation as the opportunity cost of litigation: can it be sustained in the long term?Minerals & Energy - Raw Materials Report, Vol. 20, 2, June pp. 28-35.GlobalLegal
DS201705-0872
2017
Adetunji, J.Rollinson, H., Adetunji, J., Lenaz, D., Szilas, K.Archean chromitites show constant Fe3+/Efe in Earth's asthenospheric mantle since 3.8 Ga.Journal of Petrology, in press available 42p.Europe, Greenland, Africa, ZimbabweMelting, Fiskenaesset Compex, Ujaragssuit, Limpopo belt
DS201809-2107
2018
Adhikari, A.Vadlamani, R., Bera, M.K., Samata, A., Mukherjee, S., Adhikari, A., Sarkar, A.Oxygen, Sr and Nd isotopic evidence from kyanite eclogite xenoliths ( KL-2 pipe, Wajrakarur) for pre 1.1 Ga mantle metasomatism in eastern Dharwar SCLM.Goldschmidt Conference, 1p. AbstractIndiadeposit - KL-2

Abstract: Kyanite-eclogite xenoliths from Wajrakarur are considered as remnants of subducted ocean-floor crust. Here trace element concentration and isotopic data are presented in garnet (Grt) and kyanite (Ky) from xenoliths KL-2 E1-E4, characterized by. We use the precise 87Sr/86Sr host kimberlite groundmass perovskite ratio (0.70312-0.70333, as a proxy for the extent of kimberlitic magma infiltration at 1.1 Ga. The xenolithic Grt and Cr-rich (upto 1506 ppm) Ky have more radiogenic 87Sr/86Sr values than kimberlite, at 1.1 Ga, of 0.703829-0.705203 and 0.703811-0.704502, respectively. Furthermore, the Grt and Ky 143Nd/144Nd ratios, at 1.1 Ga, are 0.509321-0.511372 and 0.510951-0.511156, respectively, and are distinctly lower than those of the host kimberlite (0.511870-0.512290). This indicates that the infiltration of kimberlitic fluid has not altered the 87Sr/86Sr and 143Nd/144Nd ratios in the Grt and Ky, and therefore their isotope compositions must be inherited and predate the kimberlite magma generation event at 1.1 Ga. Trace elements in Grt and Ky indicate extreme metasomatism (Sr in Grt 104-296 ppm, in Ky 672-8713 ppm [limit Sr<2ppm] and Nb in Grt 0.64-1.78 ppm, in Ky 1.7-4.54 ppm [limit Nb<0.5ppm]). The xenoliths underwent at least one major melting event inferred from extreme depletions in Re, Os and 177Os/178Os ratios [5]. Their mantle-like ?18O values (Grt 5.3-5.4‰, Ky 5.3-5.9‰), positive Eu anomalies in both Grt and Ky (similar to Group 1 HREE-depleted garnets of) suggests that the protolith likely was a chromite-bearing leucogabbro, emplaced as a high-pressure cumulate at the crust-mantle boundary, which was later eclogitized due to deep-seated subduction and underwent episodes of extreme melting and metasomatism before 1.1 Ga and at least before 1.7 Ga, as inferred from their youngest Re depletion dates.
DS201909-2100
2019
Adhikari, A.Vadlamani, R., Bera, M.K., Samanta, A., Mukherjee, S., Adhikari, A., Sarkar, A.Oxygen, Sr and Nd isotopic evidence from kyanite-eclogite xenoliths ( KL-2 pipe, Wajrakarur) for pre- 1.1 Ga mantle metasomatism in eastern Dharwar SCLM.Goldschmidt2019, 1p. AbstractIndiadeposit - KL-2

Abstract: Kyanite-eclogite xenoliths from Wajrakarur are considered as remnants of subducted ocean-floor crust [1]. Here trace element concentration and isotopic data are presented in garnet (Grt) and kyanite (Ky) from xenoliths KL-2 E1-E4, characterized by [2]). We use the precise 87Sr/86Sr host kimberlite groundmass perovskite ratio (0.70312-0.70333, [3]) as a proxy for the extent of kimberlitic magma infiltration at 1.1 Ga. The xenolithic Grt and Cr-rich (upto 1506 ppm) Ky have more radiogenic 87Sr/86Sr values than kimberlite, at 1.1 Ga, of 0.703829-0.705203 and 0.703811-0.704502, respectively. Furthermore, the Grt and Ky 143Nd/144Nd ratios, at 1.1 Ga, are 0.509321-0.511372 and 0.510951-0.511156, respectively, and are distinctly lower than those of the host kimberlite (0.511870-0.512290, [4]). This indicates that the infiltration of kimberlitic fluid has not altered the 87Sr/86Sr and 143Nd/144Nd ratios in the Grt and Ky, and therefore their isotope compositions must be inherited and predate the kimberlite magma generation event at 1.1 Ga. Trace elements in Grt and Ky indicate extreme metasomatism (Sr in Grt 104-296 ppm, in Ky 672-8713 ppm [limit Sr<2ppm] and Nb in Grt 0.64-1.78 ppm, in Ky 1.7-4.54 ppm [limit Nb<0.5ppm]). The xenoliths underwent at least one major melting event inferred from extreme depletions in Re, Os and 177Os/178Os ratios [5]. Their mantle-like ?18O values (Grt 5.3-5.4‰, Ky 5.3-5.9‰), positive Eu anomalies in both Grt and Ky (similar to Group 1 HREE-depleted garnets of [1]) suggests that the protolith likely was a chromite-bearing leucogabbro, emplaced as a high-pressure cumulate at the crust-mantle boundary, which was later eclogitized due to deep-seated subduction and underwent episodes of extreme melting and metasomatism before 1.1 Ga and at least before 1.7 Ga, as inferred from their youngest Re depletion dates [5].
DS201701-0001
2016
Adhikary, D.Adhikary, D., Sahoo, R.K., Maurya, N.Petrography and geochemistry of new finding alkaline lamprophyre dyke in eastern margin of the eastern Dharwar craton, near Khammam, Telangana India.Acta Geologica Sinica, Vol. 90, 1, p. 197. abstractIndiaLamprophyre
DS1995-0007
1995
Adisoma, G.S.Adisoma, G.S., Hester, M.G.Grade estimation and its precision in mineral resources: the jackknifeapproachAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, No. 95-59, 8pArizonaCopper, Geostatistics -jackknife
DS1996-0005
1996
Adisoma, G.S.Adisoma, G.S., Hester, M.G.Grade estimation and its precision in mineral resources: the jacknifeapproachMining Engineering, Vol. 48, No. 2, Feb. pp. 84-88United StatesOre reserves, geostatistics, Kriging, Jacknife approach
DS1992-0008
1992
Adjei, A.O.Adjei, A.O.The significance of northeast southwest parallel fractures in the West African CratonInternational Basement Tect., No. 7, pp. 49-60.GlobalCraton, Metallogeny - not specific to diamonds
DS201412-0300
2014
Adjerid, Z.Godard, G., Chabou, M.C., Adjerid, Z.First African diamonds discovered in Algeria by the ancient Arabo-Berbers: history and insight into the source rocks.Comptes Rendus Geoscience, Vol. 346, 7-8, pp. 179-189.Africa, AlgeriaHistory, lamproite
DS1988-0001
1988
Adkins-Heljeson, D.M.Adkins-Heljeson, D.M., Berendsen, P., McCafferty, A.E.Correlation of aeromagnetic and gravity dat a in the Joplin 2degree quadrangle of Kansas and Missouri to basement composition and structureGeological Society of America Abstracts with Program, Vol. 20, No. 2, January p. 89. Sth. Central, LawrenceGlobalMid continent, Tectonics
DS1990-0997
1990
Adkins-Heljeson, D.M.McCafferty, A.E., Adkins-Heljeson, D.M., Yarger, H.L.Complete bouguer gravity anomaly map of the Joplin Quadrangle Kansas andMissouriUnited States Geological Survey (USGS) Open File No. 89-0283, 1 sheet 1: 250, 000 $3.25, GlobalGeophysics-gravity
DS201312-0005
2013
Adler, C.Adler, C.A new line of sight - Mellier CEO of De Beers.Optima, Dec. pp. 10-19.GlobalMellier discussion
DS1860-0072
1869
Adler, N.Adler, N.Diamanten in Sued-afrika Vaal RiverVerhandlungen der kk geologischen Reichsanstalt (WIEN), ALSO: NEUES JAHRB. MI, PP. 351-352; (1870 P. 485).Africa, South Africa, Cape ProvinceHistory
DS1991-0921
1991
Admakin, L.A.Kostrovitskii, S.I., Admakin, L.A.Occurrence of petrified wood in the Obnazhennaya kimberlite pipeSoviet Geology and Geophysics, Vol. 32, No. 11, pp. 70-71Russia, YakutiaFossil wood, Deposit -Obnazhennaya
DS1989-1338
1989
Admou, H.Saquaque, A., Admou, H., Karson, J., Hefferan, K., Reuber, I.Precambrian accretionary tectonics in the Bou-Azzer-El Graara region, Anti-Atlas, MoroccoGeology, Vol. 17, No. 12, December pp. 1107-1110MoroccoOphiolite, Late Proterozoic
DS2000-0401
2000
Admou, H.Hefferan, K.P., Admou, H., Saquaque, A.Anti-Atlas (Morocco) role in Neoproterozoic western GondwanaPrecambrian Research, Vol. 103, No. 1-2, Sept. pp.89-96.MoroccoTectonics, Gondwana
DS201805-0952
2017
Admou, H.Ikenne, M., Lahna, A.A., Soderlund, U., Tassinar, C.C.G., Ernst, R.E., Pin, Ch., Youbi, N., El Aouli, EH., Hafid, A., Admou, H., Mata, J., Bouougri, EH., Boumehdi, M.A.New Mesoproterozoic age constraints for the Taghdout Group, Anti-Atlas ( Morocco): toward a new lithostratigra[hic framework for the Precambrian in the NW margin of the West African Craton.The First West African Craton and Margins International Workshop WACMA, Held Apr. 24-29. 1p. AbstractAfrica, Moroccogeochronology
DS1993-1838
1993
Adodin, E.E.Zudin, N.G., Adodin, E.E.Preliminary classification, evaluation and reprocessing of diamondsDiamonds of Yakutia, pp. 177-180.Russia, YakutiaDiamond evaluation
DS1989-0006
1989
Adrian, J.Adrian, J., Winfield, G.M.Geochemical and mineralogical features of a re-enriched zone within the Goudini carbonatite complex Transvaal South AfricaXiii International Geochemical Exploration Symposium, Rio 89 Brazilian Geochemical, p. 61-62. AbstractSouth AfricaCarbonatite, Goudini
DS201412-0002
2014
Adriao, A.Adriao, A., Conceicao, R., Carniel, L., Gervasoni, F.Chemical and isotopic evidences of mantle source heterogeneity in the RosaRio do Sul kimberlite province.Goldschmidt Conference 2014, 1p. AbstractSouth America, BrazilDeposit - RosaRio do Sul
DS1996-0006
1996
Adu-Anokye, S.Adu-Anokye, S., Cobblah, A., Mireku-Gyimah, D.Geostatistical mineral reserve estimation of a Diamondiferous deposit - acase study.Surface Mining, 1996, South African Institute of Mining and Metallurgy (IMM)., pp. 93-100.GhanaBirim diamond field, Diamond reserves, geostatistics
DS200412-0003
2004
Adushkin, V.V.Adushkin, V.V., Ovchinnikov, V.M.The mosaic in reflections from the Earth's solid core boundary.Doklady Earth Sciences, Vol. 397, 6, July-August pp. 883-885.MantleGeophysics - seismics
DS202202-0186
2021
Adushkin, V.V.Adushkin, V.V., Goev, A.G., Sanina, I.A., Fedorov, A.V.The deep velocity structure of the Central Kola Peninsula obtained using the receiver function technique.Doklady Earth Sciences, Vol. 501, pp. 1049-1051.Russia, Kola Peninsulageophysics - seismics

Abstract: New results are presented on the features of the deep velocity structure of two of the three main tectonic blocks that make up the Kola region-Murmansk and Belomorskii-by the P receiver function technique. The research is based on data from the broadband seismic stations Teriberka and Kovda. The results are compared with the models obtained by mutual inversion of PRF and SRF using the data from the stations Apatity and Lovozero. It is shown that the crust has a two-layer structure with the border at a depth of 11 km under the Murmansk block and at a depth of 15 km under the Kola and Belomorskii blocks. The crust thickness of the Murmansk, Belomorskii, and Kola blocks are 35, 33, and 40 km, respectively. The presence of the MLD was revealed in all tectonic structures analyzed for the first time, with a top at a depth of about 70 km for the Murmansk and Belomorskii blocks and 90 km for the Kola block and a bottom at 130-140 km for all structures.
DS2000-1014
2000
Ady, B.E.Whittaker, R.C., Karpuz, R., Wheeler, W., Ady, B.E.4D regional tectonic modeling: plate reconstruction using a geographic information systemGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000, 4p. abstract.Greenland, NorwayTectonics - GIS
DS200912-0002
2009
Aeh, A.Aeh, A., Gerdes, A., Barton, J.H.Archean accretion and crustal evolution of the Kalahari craton: the zircon age and Hf isotope record of granitic rocks- Barberton/Swaziland to Francistown Arc.Journal of Petrology, Vol. 50, 5, pp. 933-966.Africa, South AfricaGeochronology
DS200512-0025
2004
Aeolus Lee, C.T.Anser Li, Z.X., Aeolus Lee, C.T.The constancy of upper mantle fo2 through time inferred from V/Sc ratios in basalts.Earth and Planetary Science Letters, Vol. 228, 3-4, pp. 483-493.MantlePetrology - basalts
DS200612-0003
2005
Aeoluslee, C.T.Aeoluslee, C.T., Leeman, W.P., Canil, D., Li, Z.X.Similar V/Sc systematics in MORB and Arc basalts: implications for the oxygen fugacities of their mantle source regions.Journal of Petrology, Vol. 46, 11, pp. 2313-2336.MantlePetrology
DS202108-1277
2021
Aertgeerts, G.Derycke, A., Gautheron, C., Barbarand, J., Bourbon, P., Aertgeerts, G., Simon-Labric, T., Sarda, P., Pinna-Jamme, R., Boukari, C., Gaurine, F.French Guiana margin evolution: from Gondwana break-up to Atlantic Ocean.Terra Nova, Vol. 33, 4, pp. 415-422. pdfSouth America, French GuianaGuiana Shield

Abstract: Knowledge of the Guiana Shield evolution during the Gondwana break-up is key to a better understanding of craton dynamics and margin response to transtensional opening. To improve this knowledge, we investigated the dynamics and thermal evolution of French Guiana, using several low-temperature thermochronology methods applied to basement rocks, including apatite and zircon (U-Th)/He and apatite fission tracks. Inverse modelling of results allows us to reconstruct the Phanerozoic thermal history of French Guiana margin and to give a preview of the Guiana Shield evolution. Three main events are inferred: firstly, a long-term period of relative stability since ~1.2 Ga, with no strong evidence for any erosional or burial event (>5-7 km); secondly, a heating phase between ~210 and ~140 Ma consistent with the Central Atlantic Magmatic Province-related event. Finally, an exhumation phase between ~140 and ~90 Ma, triggered by the Equatorial Atlantic opening, brought samples close to the surface (<40°C).
DS201012-0247
2010
AfanasevGrakhanov, S.A., Malanin, Yu.A., Pavlov, Afanasev, Pokhilenko, Gerasimchuk, LipashovaRhaetian diamond placers in Siberia.Russian Geology and Geophysics, Vol. 51, pp. 127-135.Russia, Yakutia, SakhaAlluvials
DS201612-2272
2016
Afanasev, A.Afanasev, A., Belyaeva, E.Linear stability analysis for hydrothermal alteration of kimberlitic rocks.Geophysical Journal International, Vol. 205, 3, pp. 1874-1885.TechnologyAlteration

Abstract: The influx of groundwater into hot kimberlite deposits results in the reaction of water with olivine-rich rocks. The products of the reaction are serpentine and release of latent heat. The rise of temperature due to the heat release increases the rate of the reaction. Under certain conditions, this self-speeding up of the reaction can result in instabilities associated with a significantly higher final serpentinisation in slightly warmer regions of the kimberlite deposit. We conduct linear stability analysis of serpentinisation in an isolated volume of porous kimberlitic rocks saturated with water and an inert gas. There is a counteracting interplay between the heat release tending to destabilise the uniform distribution of parameters and the heat conduction tending to stabilise it by smoothing out temperature perturbations. We determine the critical spatial scale separating the parameters where one phenomenon dominates over another. The perturbations of longer-than-critical length grow, whereas the perturbations of shorter-than-critical length fade. The analytical results of the linear stability analysis are supported by direct numerical simulations using a full nonlinear model.
DS1983-0002
1983
Afanasev, B.P.Afanasev, B.P., Yangin, YU.T.Buried Primary Dispersion Streams of Kimberlite Bodies in The MalobuTo bin Skii Region.Geology And Geophysics, Vol. 24, No. 6, PP. 76-81.Russia, YakutiaGeochemistry, Sampling
DS200712-0471
2007
Afanasev, V.Izbekov, E., Podyachev, B., Afanasev, V.Signs of symmetric diamond concentration in the eastern Siberian Platform.Doklady Earth Sciences, Vol. 411, 9, pp. 1339-1340.RussiaDiamond genesis
DS200712-0472
2007
Afanasev, V.Izbekov, E., Podyachev, B., Afanasev, V.Signs of symmetric diamond concentration in the eastern Siberian Platform.Doklady Earth Sciences, Vol. 411, 9, pp. 1339-1340.RussiaDiamond genesis
DS200712-1018
2007
Afanasev, V.Sonin, V., Zhimulev, E., Afanasev, V., Fedorov, I., Cheperov, A.Diamond interaction with silicate melts in a hydrogen atmosphere.Geochemistry International, Vol. 45, 4, pp. 399-404.TechnologyMelting
DS200712-1019
2007
Afanasev, V.Sonin, V., Zhimulev, E., Afanasev, V., Fedorov, I., Cheperov, A.Diamond interaction with silicate melts in a hydrogen atmosphere.Geochemistry International, Vol. 45, 4, pp. 399-404.TechnologyMelting
DS201709-1981
2017
Afanasev, V.Egorova, E., Afanasev, V.Mineralogical features for determining age of kimberlites from Siberian craton by kimberlitic indicator minerals from placers. Mayat, Muna, Tychan, KenkemeGoldschmidt Conference, abstract 1p.Russia, Siberiageochemistry

Abstract: The history of kimberlite magmatism in the Siberian craton comprised the Middle Paleozoic (Late Devonian), Triassic, and Jurassic-Cretaceouse events. The Middle Paleozoic event produced greatest amounts of diamond-bearing kimberlites; diamond contents in the Triassic rocks are much lower, while the Jurassic-Cretaceous kimberlites are actually barren [1]. Minerals derived from kimberlites of different ages often coexist in placers and dispersion trains, which poses problems to the use of mineralogical methods for diamond exploration. The problem can be solved by knowing the morphological features of kimberlite indicator minerals typical of each magmatic event [2]. Garnets from Middle Paleozoic kimberlites have the following features: a) chemistry corresponding to diverse parageneses, including those of diamond assemblage; b) weak to strong wear; predominant medium and high wear degrees; c)signatures of dissolution in Late Devonian laterite weathering profiles. Garnets from Triassic kimberlites differ in a) lower paragenetic diversity; few or absent garnets of diamond assemblage; b) only low wear degree; strong wear restricted to garnets from Triassic kimberlites hosted by coastal sediments; c) no dissolution signatures. Jurassic-Cretaceous ages of kimberlites can be inferred from a) changes in paragenetic diversity as a result of deep metasomatism and predominance of shallow lherzolite varieties; no diamond assemblage garnets; b) weak wear; c) no dissolution signatures. The approach was used to estimate the ages of kimberlites in some kimberlite provinces. As a result, we inferred the existence of Middle Paleozoic kimberlites in the Kyutyungde graben, in the catchments of the Mayat, Billakh (Anabar area), and Muna rivers, in the MarkhaMorkoka interfluve, and in the Tychan diamond province (Krasnoyarsk region); Triassic kimberlites in the northern slope of the Olenek uplift and within the Bulkur uplift; and Late Jurassic-Early Cretaceous kimberlites in the Kenkeme catchment north of Yakutsk city.
DS1984-0001
1984
Afanasev, V.P.Afanasev, V.P., Sobolev, N.V., Kharkiv, A.D.The Evolution of the Chemical Composition of Pyrope Associations in Old Dispersion Halos Around Kimberlite Bodies.Soviet Geology And Geophysics, Vol. 25, No. 2, PP. 130-135.RussiaGeochemistry
DS1984-0002
1984
Afanasev, V.P.Afanasev, V.P., Varlamov, V.A., Garanin, V.K.The Abrasion of Minerals in Kimberlites in Relation to the Conditions and Distances of Their Transportation.Soviet Geology And Geophysics, Vol. 25, No. 10, OCTOBER PP. 112-117.RussiaMorphology, Petrography
DS1985-0001
1985
Afanasev, V.P.Afanasev, V.P., Zinchuk, N.N., Boris, E.I.Characteristics of concentration of a kimberlite material inancient sedimentary deposits of Yakutia. (in Russian)Rudn. Spets. Osad. Form. Sib. Dalnego Vostoka, (in Russian), pp. 129-133RussiaBlank
DS1986-0473
1986
Afanasev, V.P.Kvasnitsa, V.N., Vuiki, V.I., Tsymbal, Yu.S., Afanasev, V.P., et al.Crystal morphology and paragenesis of cut garnets fromkimberlites.(Russian)Mineral. Zhurn., (Russian), Vol. 8, No. 1, pp. 30-44RussiaPyrope, Morphology
DS1987-0001
1987
Afanasev, V.P.Afanasev, V.P., Zinchuk, N.N.Minerogenesis of ancient placers of diamonds on the eastern edge of the Tunguska syncliseSoviet Geology and Geophysics, Vol. 28, No. 1, pp. 79-84RussiaPlacers, Genesis
DS1989-0007
1989
Afanasev, V.P.Afanasev, V.P.Technique for mapping of heavy mineral concentrate dispersion haloes In kimberlite bodiesSoviet Geology and Geophysics, Vol. 30, No. 5, pp. 32-37RussiaGeochemistry, Prospecting/sampling
DS1989-0008
1989
Afanasev, V.P.Afanasev, V.P.Prospecting based on heavy mineral seperates in the Yakutia Diamond bearing province.(Russian)Sov. Geol., (Russian), No. 1, pp. 24-33RussiaHeavy minerals, Prospecting
DS1991-0003
1991
Afanasev, V.P.Afanasev, V.P., Sobolev, N.V., Pokhilenko, N.P.Exogenous changes of the indicator minerals at the formation of mineralogical halos of kimberlite bodiesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 1-2RussiaAlluvial, Diamonds -mineralogy
DS1992-1446
1992
Afanasev, V.P.Sobolev, N.V., Afanasev, V.P., Pokhilenko, N.P., Kaminsky, F.V.Pyropes and diamonds of the Algerian Sahara.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 325, No. 2, pp. 367-373.AlgeriaIndicator minerals, Pyropes, diamonds
DS1993-1499
1993
Afanasev, V.P.Sobolev, N.V., Pokhilenko, N.P., Afanasev, V.P.Kimberlite pyropes and chromites morphology and chemistry as indicators of diamond grade in Yakutian and Arkangelsk Provinces.Mid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 63-70.Russia, Commonwealth of Independent States (CIS), YakutiaMineral chemistry, Diamond morphology
DS1994-0012
1994
Afanasev, V.P.Afanasev, V.P., Sobolev, N.V., Kirillov, E.A., Yusupov, I.S.Relative abrasive stability of pyrope and pyroilmenite -indicator minerals of kimberlite.(Russian)Doklady Academy of Sciences Nauk, Vol. 337, No. 3, July pp. 359-362.Russia, SiberiaMineralogy, Indicator minerals
DS1995-2000
1995
Afanasev, V.P.Vishnevsky, S.A., Afanasev, V.P., Koptil, V.I.Impact diamonds : their features, origin and significanceProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 657-659.GlobalDiamonds -impact, Meteorites
DS1998-0008
1998
Afanasev, V.P.Afanasev, V.P., Zinchuk, N.N., Koptil, V.I.Diamond polygenesis: evidence for the native sources of placers of northeastern Siberian PlatformDoklady Academy of Sciences, Vol. 361A, No. 6, pp. 761-4.Russia, SiberiaAlluvials, placers, Genesis, origin
DS1999-0001
1999
Afanasev, V.P.Afanasev, V.P., Zinchuk, N.N.Main lithodynamic types of dispersion haloes of index kimberlite mineral sand environments of their formationGeo. Ore Dep., Vol. 41, No. 3, pp. 252-RussiaGeochemistry, Lithogeochemistry, indicator minerals
DS2000-0006
2000
Afanasev, V.P.Afanasev, V.P., Pokhilenko, Loginova, Zinchuk, EfimovaProblem of false kimberlite indicators: a new morphogenetic type Cr spinellide Diamondiferous areas.Russian Geology and Geophysics, Vol.41,12,pp.1676-89., Vol.41,12,pp.1676-89.RussiaGeochemistry - indicators, Chrome spinellide
DS2000-0007
2000
Afanasev, V.P.Afanasev, V.P., Pokhilenko, Loginova, Zinchuk, EfimovaProblem of false kimberlite indicators: a new morphogenetic type Cr spinellide Diamondiferous areas.Russian Geology and Geophysics, Vol.41,12,pp.1676-89., Vol.41,12,pp.1676-89.RussiaGeochemistry - indicators, Chrome spinellide
DS2001-0005
2001
Afanasev, V.P.Afanasev, V.P., Zinchuk, Pkhilenko, Krivonos, YanyginKarst role in the formation of diamond placers of the Muno Markhinskii interfluve Yakutsk diamond provinceGeol. Ore Depos., Vol. 43, No. 3, pp. 234-8.Russia, SiberiaAlluvials, Geomorphology
DS2002-1528
2002
Afanasev, V.P.Sonin, V.M., Zhimulev, E.I., Afanasev, V.P., Chepurov, A.I.Genetic aspects of the diamond morphologyGeology of Ore Deposits, Vol. 44, 4, pp. 291-299.GlobalDiamond - morphology, genesis
DS200712-0473
2006
Afanasev, V.P.Izbekov, E.D., Podyachev, B.P., Afanasev, V.P.Signs of symmetric diamond concentration in the eastern Siberian platform.Doklady Earth Sciences, Vol. 411, 9, Nov-Dec. pp. 1339-1340.Russia, SiberiaDiamond genesis
DS200712-1022
2007
Afanasev, V.P.Sonin, V.M., Zhimulev, E.I., Afanasev, V.P., Fedorov, I.I., Chepurov, A.I.Diamond interaction with silicate melts in a hydrogen atmosphere.Geochemistry International, Vol. 45, 4, pp. 399-404.MantleDiamond genesis
DS200812-0002
2008
Afanasev, V.P.Afanasev, V.P., Nikolenko, E.I., Tychikov, N.S., Titov, A.T., Tolstov, A.V., Kornilova, V.P., Sobolev, N.V.Mechanical abrasion of kimberlite indicator minerals: experimental investigations.Russian Geology and Geophysics, Vol. 49, 2, pp. 91-97.TechnologyMineralogy
DS200812-0798
2008
Afanasev, V.P.Nikolenko, E.I., Afanasev, V.P., Pokhilenko, N.P.Garnets of crustal parageneses in alluvial deposits of the eastern Siberian platform: genesis and search significance.Russian Geology and Geophysics, Vol. 49, pp. 655-666.Russia, YakutiaMuna Markha drainage
DS201012-0002
2009
Afanasev, V.P.Afanasev, V.P., Zinchuk, N.N., Logvinova, A.M.Distribution of placer diamonds related to Precambrian sources.Geology of Ore Deposits, Vol. 51, 8, pp. 675-683.RussiaAlluvials
DS201012-0541
2010
Afanasev, V.P.Nikolenko, E.I., Afanasev, V.P., Pokhilenko, N.P.Pecularities of the composition of zoned picroilmenites from the Massadou field, (Guinea) and Dachanya pipe ( Yakutia) kimberlites.Doklady Earth Sciences, Vol. 434, 2, pp.1386-1389.Africa, Guinea, RussiaGeochemistry - Massadou, Dachanaya
DS201012-0590
2010
Afanasev, V.P.Pokhilenko, N.P., Afanasev, V.P., Vavilov, M.A.Behaviour of kimberlite indicator minerals during the formation of mechanical dispersion halos in glacial settings.Lithology and Mineral Resources, Vol. 45, 4, pp. 324-329.Canada, Northwest TerritoriesDeposit - CL 25
DS201012-0741
2010
Afanasev, V.P.Sonin, V.M., Zhimulev, E.I., Chepurov, A.I., Afanasev, V.P., Pokhilenko, N.P.High pressure etching of diamond in chloride melt in the presence of aqueous fluid.Doklady Earth Sciences, Vol. 434, 2, pp. 1359-1361.TechnologyUHP
DS201112-0005
2011
Afanasev, V.P.Afanasev, V.P., Lobanov, S.S., Pokhilenko, N.P., Koptil, Mityukhin, Gerasimchuk, Pomazanski, GorevPolygenesis of diamonds in Siberian Platform. Five groups of diamonds have been distinquished.Russian Geology and Geophysics, Vol.l 52, pp. 259-274.Russia, SiberiaDiamond placers, alluvials
DS201212-0523
2012
Afanasev, V.P.Nikolenko, E., Afanasev, V.P., Chepurov, A.Fe rich ilmenite and kimberlite melt interaction, experimental researchs.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, Africa, Angola, GuineaDeposit - Dachnaya, Catoca, Massadon
DS201212-0562
2012
Afanasev, V.P.Pokhilenko, N.P., Afanasev, V.P., McDonald, J.A., Vavilov, M.A., Kulgin, S.S., Pokhilenko, L.N., Golovin, A.V., Agashev, A.M.Kimberlite indicator minerals in terrigene sediments of lower part of Mackenzie River Basin, NWT, Canada: evidence of new craton with thick lithosphere.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Northwest TerritoriesGeochemistry - KIMS
DS201312-0649
2012
Afanasev, V.P.Nikolenko, E.I., Afanasev, V.P., Chepurov, A.I., Sonin, V.M., Poikhilenko, N.P.Experimental study of the interaction between emoilmenite and kimberlite melt at a pressure of 2 Gpa.Doklady Earth Sciences, Vol. 447, 2, pp. 1306-1309.Africa, GuineaDeposit - Massadou
DS201412-0308
2014
Afanasev, V.P.Goryainov, S.V., Likhacheva, A.Y., Rashchenko, S.V., Shubin, A., Afanasev,V.P., Poikilenko, N.P.Raman identification of lonsdalaeite in Popigai impactites.Journal of Raman Spectroscopy, Vol. 45, 4, pp. 305-313.RussiaLonsdaleite
DS201612-2297
2016
Afanasev, V.P.Egorova, E.O., Afanasev, V.P., Pokhilenko, N.P.Middle Paleozoic kimberlite magmatism in the northeastern Siberia.Doklady Earth Sciences, Vol. 470, 2, pp. 1023-1026.Russia, SiberiaDeposit - Billyakh River placers

Abstract: The mineral chemistry and crystal morphology of kimberlite pyropes from the Billyakh River placer in the northeastern Siberian craton are characterised in terms of the placer history. The pyropes bear signatures of chemical weathering (dissolution), presumably in a Middle Paleozoic laterite profile, and therefore were originally hosted by Middle Paleozoic kimberlites. The broad occurrence of placer pyropes with lateritic dissolution signatures points to the presence of Middle Paleozoic diamond-bearing kimberlites in the study area.
DS201212-0678
2012
Afanasev, V.P.D.Smith, E.M., Kopylova, M.G., Nowell, G.M., Pearson, D.G., Ryder, J., Afanasev, V.P.D., Beeby, A.The contrast in trace element chemistry and volatile composition between fluid inclusions n fibrous and octahedral diamonds.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, Ontario, WawaDiamond inclusions
DS201212-0419
2012
Afanasev, Z.L.Lokhov, K., Lukyanova, L., Antonev, A.V., Polekhovsky, I.N., Antonov, A.V., Afanasev, Z.L., Bogomolov, E.S., Sergeev, S.A.U Pb and Lu-Hf isotopic systems in zircons and Hf-Nd isotopic systemization of the Kimozero kimberlites, Karelia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, Archangel, Kola PeninsulaDeposit - Kimozero
DS1975-0905
1979
Afanaseyev, V.P.Afanaseyev, V.P., Kharkiv, A.D., Sokolov, V.N.The Morphology and Morphogenesis of the Garnets in the Kimberlites of Yakutia.Soviet Geology And Geophysics, Vol. 20, No. 3, PP. 65-75.RussiaGenesis
DS1991-0004
1991
Afanaseyev, V.P.Afanaseyev, V.P.Regularities of evolution of kimberlite minerals and their associations during formation of concentrate haloesSoviet Geology and Geophysics, Vol. 32, No. 3, pp. 78-84RussiaKimberlite geochemistry, Indicator mineralogy
DS200512-0036
2004
AfanasievAshchepkov, I.V., Vladykin, Rotman, Loginova, Afanasiev, Palessky, Saprykin, Anoshin, Kuchkin, KhmelnikovaMir and Internationalnaya kimberlite pipes - trace element geochemistry and thermobarometry of mantle minerals.Deep seated magmatism, its sources and their relation to plume processes., pp. 194-208.RussiaGeobarometry - Mir, International
DS200612-0047
2006
AfanasievAshchepkov, I.V., Vladykin, Sobolev, Pokhilenko, Rotman, Logvinova, Afanasiev, Pokhilenko, KarpenkoReconstruction of the mantle sequences and the structure of the feeding and vein magmatic systems beneath the kimberlite fields of Siberian platform.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 79-103.Russia, SiberiaDyke systems
DS200612-0048
2006
AfanasievAshchepkov, I.V., Vladykin, Sobolev, Pokhilenko, Rotman, Logvinova, Afanasiev, Pokhilenko, KarpenkoVariations of the oxygen conditions in mantle column beneath Siberian kimberlite pipes and it's application to lithospheric structure of feeding systems.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 125-144.Russia, SiberiaRedox
DS201012-0016
2010
AfanasievAshchepkov, I., Afanasiev, Vladykin, Pokhilenko, Ntaflos, Travin, Ionov, Palessky, Logvinova, Kuligin, MityukhinReasons of variations of the mineral compositions of the mantle rocks beneath the Yakutian kimberlite province.International Mineralogical Association meeting August Budapest, abstract p. 141.Russia, YakutiaGeothermometry
DS200412-0004
2004
Afanasiev, V.Afanasiev, V., et al.Interpreting diamond morphology. The shape and surface features of diamonds are characteristic of primary deposits. Assist explRough Diamond Review, No. 5, June, pp.RussiaDiamond morphology, placers
DS200512-0003
2004
Afanasiev, V.Afanasiev, V.Surface modifications to diamonds often occur from damage due to alluvial transportation and from chemical attack after growth. These features can contribute to characterisationRough Diamond Review, No.7, December pp.Diamond morphology, placers, characteristics
DS200912-0163
2009
Afanasiev, V.De Stefano, A., Kopylova, M.C., Cartigny, P., Afanasiev, V.Diamonds and eclogites of the Jericho kimberlite ( Northern Canada).Contributions to Mineralogy and Petrology, Vol. 158, 3, Sept. pp. 295-315.Canada, NunavutDeposit - Jericho
DS201312-0006
2013
Afanasiev, V.Afanasiev, V., Agashev, A., Pokhilenko, N.Dispersion haloes of kimberlite indicator minerals in the Siberian Platform: history and formation conditions.Geology of Ore Deposits, Vol. 55, 4, pp. 256-264.RussiaMineral chemistry
DS201412-1007
2014
Afanasiev, V.Yelisseyev, A., Khrenov, A., Afanasiev, V., Pustavarov, V., Gromilov, S., Panchenko, A., Poikilenko, N., Litasov, K.Luminesence of impact diamonds from the Popigai astrobleme.V.S. Sobolev Institute of Geology and Mineralogy Siberian Branch Russian Academy of Sciences International Symposium Advances in high pressure research: breaking scales and horizons ( Courtesy of N. Poikilenko), Held Sept. 22-26, 2p. AbstractRussia, SiberiaDiamond luminescence
DS201502-0036
2015
Afanasiev, V.Afanasiev, V., Ashchekov, I., Nikolenko, E.Concentrates and mantle xenocrysts from the Lao River Guinea and reconstruction of the mantle structure. Economic Geology Research Institute 2015, Vol. 17,, # 2484, 1p. AbstractAfrica, GuineaKimberlite dykes
DS201502-0087
2015
Afanasiev, V.Nikolenko, E., Tychkov, N., Afanasiev, V.Mantle xenocrysts of the Chompolo kimberlite field, Aldan shield, south Yakutia.Economic Geology Research Institute 2015, Vol. 17,, # 2471, 1p. AbstractRussiaDeposit - Chompolinskoe
DS201509-0439
2015
Afanasiev, V.Yelisseyev, A., Khrenov, A., Afanasiev, V., Pustovarov, V., Gromilov, S., Panchenko, A., Pokhilenko, N., Litasov, K.Luminescence of natural carbon nanomaterial: impact diamonds from the Popigai crater.Diamond and Related Materials, Vol. 58, pp. 69-77.RussiaDeposit - Popigai

Abstract: Impact diamonds (IDs) from the Popigai crater are aggregates of nanoparticulate graphite and cubic and hexagonal diamonds. IDs demonstrate broad-band emissions at 3.05, 2.8, 2.3 and 2.0 eV, which are associated with structural defects and are similar to those in detonation ultra-dispersed diamonds and CVD diamond films. A doublet with components at 1.7856 and 1.7892 eV in some ID samples is related to R1,2 lines of Cr3 + ions in corundum inclusions. The presence of N3, H3, NV0 and NV? vibronic systems in some of the ID samples shows that (i) there is nitrogen impurity and (ii) samples underwent high temperature annealing that promoted vacancies and nitrogen diffusion and defect aggregation. The luminescence decay fits with a sum of two exponential components: lifetime of the fast one is in the 5 to 9 ns range. Parameters of the traps responsible for broad thermoluminescence peaks at 148, 180, 276 and 383 K were estimated.
DS201705-0884
2017
Afanasiev, V.Ugapeva, S., Goryainov, S., Afanasiev, V., Ponkratov, K.Raman mapping of mechanical stress field in diamond around a chromite inclusion.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 11676 AbstractTechnologyDiamond inclusions
DS202002-0221
2020
Afanasiev, V.Yelisseyev, A., Gromilov, S., Afanasiev, V., Sildos, I., Kiisk, V.Effect of lonsdaleite on the optical properties of impact diamonds.Diamonds & Related Materials, Vol. 101, 107640, 13p. PdfRussiaPopigai

Abstract: The special features of impact diamonds are the orientation of the nanosized grains relative to each other, the presence of hexagonal diamond (lonsdaleite, L) in a large part of the samples and the increased wear resistance. Using Raman spectroscopy and XRD, two groups of translucent samples of Popigai impact diamonds (PIDs) were selected: with and without lonsdaleite and the effect of lonsdaleite on the optical properties of the samples was studied. In all L-containing PIDs there is a strong absorption band of about 1230 cm-1 in the one-phonon region, in the mid-IR. The absorption edge is blurred and described by the Urbach rule. The estimated value of Eg ~4 eV for L is consistent with the first principles calculations. Impurity nitrogen is found only in L-free PIDs: There are signals from nitrogen-vacancy complexes in the photoluminescence (PL) spectra. Variations in the number of nitrogen atoms (N = 1 to 4) in the structure of these centers indicate significant variations in the parameters of PID annealing. L-containing PIDs are characterized by large strains in the lattice and, as a consequence, there are problems with the defect diffusion. The narrow lines in PL spectra, uncommon for diamond, can be the result of several orders of magnitude higher concentrations of impurities in PIDs formed during the solid-phase transition. The broadened peaks of 180, 278 and 383 K are distinguishable in the curves of thermostimulated luminescence (TSL) for L-free PIDs, but in the presence of L the TSL glow becomes continuous as in natural IaA-type diamonds with platelets. In general, lonsdaleite deteriorates the optical properties of impact diamonds and makes it difficult to create certain types of impurity-vacancy complexes for different applications.
DS202010-1882
2020
Afanasiev, V.Ugapeva, S., Afanasiev, V., Pavlushin, A., Eliseev, A.Main features of Yakutites from Ebelyakh placer.World Multidisciplinary Earth Sciences Symposium ( researchgate), 7p. PdfRussialonsdaleite

Abstract: Yakutites (polycrystalline diamonds with lonsdaleite admixture) from the Ebelyakh placer (Yakutia, Russia) have been studied by optical microscopy, Raman spectroscopy, and neutron diffraction in order to reveal their difference from tagamite-hosted diamonds of the Popigai impact crater. The yakutite aggregates are 2.0 mm to 13.0 mm in size and have a shapeless morphology or sometimes preserve hexagonal contours of primary graphite. Raman spectra are characterized by a broadened line in the region of cubic 3C diamond, which is interpreted as the sum of spectra from cubic 3C diamond and three peaks related to Lonsdaleite: 1338 (E1g), 1280 (A1g) and 1224 (E2g). On the surface of yakutites revealed the presence of a silicate glass film. The main elements are iron, silicon from the surrounding silicate matter. Neutron stress diffractometry showed the content of diamond and Lonsdaleite in the sample of yakutite by 50%, two cases of preferential orientation of two phases were recorded: (110) diamond // (110) Lonsdaleite; (111) diamond // (001) Lonsdaleite. Both yakutites and tagamite-hosted diamonds are of impact origin and share similarity in the phase composition consisting of more abundant diamond and subordinate amounts of lonsdaleite. Differences between them depend on the place of their formation. Yakutites were formed in the epicenter of the explosion and were thrown out of the crater at a distance of more than 550 km in radial directions, and from the vertical ejection - they got back to the crater. In tagamites, impact diamonds were formed simultaneously with the rock melting due to the shock wave that came from the epicenter. The presence of a silicate glass film on the surface of yakutites indicates that they were hardened after ejection from the crater. Yakutites represent distinct mineral fraction outside the crater. They are found as placers along with common diamonds and other detritus. Within the crater they are genetically related to suevites - tuffaceous component of the impactites and enter the crater placers due to the physical weathering of suevites. Tagamite diamonds practically do not occur in the crater placers, because tagamite is a very hard rock and in the absence of chemical weathering these diamonds can't be released. Thus, diamonds from tagamites and yakutites, having a common impact nature, differ in some properties determined by the place of formation and post-impact history.
DS202112-1951
2021
Afanasiev, V.Sonin, V., Zhimulev, E., Chepurov, A., Gryaznov, I., Chepurov, A., Afanasiev, V., Poikilenko, N.Experimental etching of diamonds: extrapolation to impact diamonds from the Popigai Crater ( Russia)MDPI, Vol. 11, 11p. Pdf Russiadeposit - Popigai

Abstract: Diamond etching in high-temperature ambient-pressure experiments has been performed aimed to assess possible postimpact effects on diamonds in impact craters, for the case of the Popigai crater in Yakutia (Russia). The experiments with different etchants, including various combinations of silicate melts, air, and inert gases, demonstrated the diversity of microstructures on {111} diamond faces: negative or positive trigons, as well as hexagonal, round, or irregularly shaped etch pits and striation. The surface features obtained after etching experiments with kimberlitic diamonds are similar to those observed on natural impact diamonds with some difference due to the origin of the latter as a result of a martensitic transformation of graphite in target rocks. Extrapolated to natural impact diamonds, the experimental results lead to several inferences: (1) Diamond crystals experienced natural oxidation and surface graphitization during the pressure decrease after the impact event, while the molten target rocks remained at high temperatures. (2) Natural etching of diamonds in silicate melts is possible in a large range of oxidation states controlled by O2 diffusion. (3) Impact diamonds near the surface of molten target rocks oxidized at the highest rates, whereas those within the melt were shielded from the oxidizing agents and remained unchanged.
DS200912-0839
2009
Afanasiev, V.A.P.A.Yelisseyev, A.A.P.A., Afanasiev, V.A.P.A., Ikorsky, V.A.N.A.Magnetic susceptibility of natural diamonds.Doklady Earth Sciences, Vol. 425, 2, pp. 330-333.TechnologyDiamond morphology
DS1986-0495
1986
Afanasiev, V.P.Lipatova, V.A., Afanasiev, V.P.Mineralogical and palynological substantiation of the existence of remedial carboniferous intermediate reservoirs of kimberlite minerals in the northMalo-BotuobinskDoklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 288, No. 6, pp. 1453-1456RussiaBlank
DS1987-0002
1987
Afanasiev, V.P.Afanasiev, V.P., Zinchuk, N.N.Metallogeny of old diamond placers of eastern frame of theTunguskasyneclise.(Russian)Geol. Geofiz.(Russian), No. 1, January ppRussiaBlank
DS1995-0008
1995
Afanasiev, V.P.Afanasiev, V.P.Geological mineralogical system of searching for diamond depositsProceedings of the Sixth International Kimberlite Conference Extended Abstracts, pp. 1-3.Russia, Siberia, YakutiaHalo identification, Indicator minerals
DS1995-2149
1995
Afanasiev, V.P.Zinchuk, N.N., Afanasiev, V.P.Genetic types and main tendencies for Diamondiferous placers formationProceedings of the Sixth International Kimberlite Conference Almazy Rossii Sakha abstract, p. 36.Russia, YakutiaPlacers, alluvials, Deposit -Siberian Platform
DS1998-0009
1998
Afanasiev, V.P.Afanasiev, V.P., Pokhilenko, N.P., Logvinova, A.M.Problem of false indicators for kimberlites and lamproites ( on the exampleof chromites).7th International Kimberlite Conference Abstract, pp. 7-8.Russia, Yakutia, ArkangelskMineralogy - chromium spinels
DS2003-1083
2003
Afanasiev, V.P.Pkhilenko, N.P., Zedgenizov, D.A., Afanasiev, V.P., Rylov, G.M., Milledge, H.J.Morphology and internal structure of diamonds from Snap Lake, King Lake kimberlite8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractNorthwest TerritoriesDiamonds - morphology, Deposit - Snap Lake, King Lake
DS200412-2181
2004
Afanasiev, V.P.Yelisseyev, A.P., Pokhilenko, N.P., Steeds, J.W., Zedgenizov, D.A., Afanasiev, V.P.Features of coated diamonds from the Snap Lake/King Lake kimberlite dyke, Slave Craton, Canada, as revealed by optical topographLithos, Vol. 77, 1-4, Sept. pp. 83-97.Canada, Northwest TerritoriesCoated diamonds, absorption, luminescence, nickel, nitr
DS200512-0004
2004
Afanasiev, V.P.Afanasiev, V.P., Griffin, W.L., Natapov, L.M., Zinchuk, N.N., Matukhin, R.G., Mikrtychiyan, G.A.Diamond prospects in the southwestern flank of the Tungusk synclise.Geology of Ore Deposits, Vol. 47, 1, pp. 45-62.Russia, YakutiaDaldyn, Tychany, geochemistry
DS201112-0006
2010
Afanasiev, V.P.Afanasiev, V.P., Tychkov, N.S., Pokhilenko, N.P., Ovchinnikov, Yu.I.About kimberlite indicator minerals in the Triassic tuffs of the Tunguska sineclise.Doklady Earth Sciences, Vol. 435, 2, pp. 1555-1559.RussiaDiamond exploration
DS201112-0536
2011
Afanasiev, V.P.Kopylova, M.G., Afanasiev, V.P., Bruce, L.F., Thurston, P.C., Tyder, J.Metaconglomerate preserves evidence for kimberlite Diamondiferous root and medium grade terrane of a pre-2.7 Ga Southern Superior protocraton.Earth and Planetary Science Letters, Vol. 312, 1-2, Dec. 1, pp. 213-235.Canada, OntarioMetaconglomerates
DS201212-0004
2012
Afanasiev, V.P.Afanasiev, V.P., Poikilenko, N.P.Abrasion of diamond: an experimental study and field evidence.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractRussia, YakutiaDiamond morphology
DS201212-0371
2012
Afanasiev, V.P.Kopylova, M.G., Miller, C., Afanasiev, V.P., Bruce, L., Thurston, P., Ryder, J.Kimberlite derived harzburgitic diamonds from a >2.7 GA southern Superior Province, Protocraton.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Ontario, WawaDiamond morphology
DS201212-0679
2012
Afanasiev, V.P.Smith, E.M., Kopylova, M.G., Nowell, G.M., Pearson, D.G., Ryder, J., Afanasiev, V.P.The contrast in trace element chemistry and volatile composition between fluid inclusions in fibrous and octahedral diamonds.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Ontario, WawaDiamond - inclusions
DS201212-0806
2012
Afanasiev, V.P.Yelisseyev, A.P., Afanasiev, V.P., Kopylova, M.G., Bulbak, T.A.The effect of metamorphic annealing and Betairradiation in optical properties of type 1AA diamonds.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, Ontario, RussiaDiamond - metamorphism
DS201312-0007
2013
Afanasiev, V.P.Afanasiev, V.P., Aschepkov, I.V., Verzhak, V.V., O'Brien, H., Palessky, S.V.PT conditions and trace element variations of picroilmenites and pyropes from placers and kimberlites in the Arkhangelsk region, NW Russia.Journal of Asian Earth Sciences, Vol. 70, pp. 45-63.Russia, Kola Peninsula, ArchangelDeposit - Verkhotinskoe , Kepinskoe fields
DS201312-0008
2013
Afanasiev, V.P.Afanasiev, V.P., Snegirev, O.V., Tychkov, N.S., Pokhilenko, N.P.Stability of kimberlite garnets exposed to chemical weathering: relationship with Cr contents.Doklady Earth Sciences, Vol. 448, 1, pp. 103-105.TechnologyGarnet mineralogy
DS201312-0714
2013
Afanasiev, V.P.Pokhilenko, N.P., Afanasiev, V.P.New prospective for diamond deposits in Siberia.PDAC 2013, March 4, 1/2p. Abstract only as conflict in his scheduleRussiaOverview - Siberia
DS201312-0846
2013
Afanasiev, V.P.Smith, E.M., Kopylova, M.G., Frezzotti, M.L., Afanasiev, V.P.Nitrogen bubbles in the mantle: evidence from diamond inclusions.GAC-MAC 2013 SS4: Diamond: from birth in the mantle to emplacement in kimberlite, abstract onlyMantleDiamond inclusions
DS201312-0847
2013
Afanasiev, V.P.Smith, E.M., Kopylova, M.G., Frezzotti, M.L., Afanasiev, V.P.Diamond inclusions reveal fugitive mantle nitrogen.Goldschmidt 2013, AbstractMantleDiamond inclusions
DS201412-0695
2014
Afanasiev, V.P.Poikhilenko, N.P., Afanasiev, V.P., Agashev, A.M., Malkovets, V.G., Poikhilenko, L.N.New archean terranes with thick lithosphere of arctic regions of Siberia and North American ancient platforms: are they prospective for Diamondiferous kimberlites?30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, Russia, CanadaKimberlite
DS201412-0696
2014
Afanasiev, V.P.Poikhilenko, N.P., Afanasiev, V.P., Poikhilenko, L.N.Polymict breccia xenolith from Noyabrskaya pipe.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, Russia, SiberiaDeposit - Noyabrskaya
DS201504-0219
2015
Afanasiev, V.P.Smith, E.M., Kopylova, M.G., Frezzotti, M.L., Afanasiev, V.P.Fluid inclusions in the Ebelyakh diamonds: evidence of CO2 liberation in eclogite and the effect of H2O on diamond habit.Lithos, Vol. 216-217, pp. 106-117.RussiaDeposit - Ebelyakh River
DS201606-1111
2016
Afanasiev, V.P.Samdanov, D.A., Afanasiev, V.P., Tychkov, N.S., Pokhilenko, N.P.Mineralogical zoning of the Diamondiferous areas: application experience of paragenetic analysis of garnets from kimberlites.Doklady Earth Sciences, Vol. 467, 1, pp. 228-231.Russia, YakutiaDeposit area - Muna-Markha

Abstract: Paragenetic analysis of pyropes from alluvial deposits of the Muna—Markha interfluve (Sakha-Yakutia Republic) made it possible to distinguish relatively uniform areas that are promising for the discovery of kimberlite bodies.
DS201608-1447
2016
Afanasiev, V.P.Ugapeva, S.S., Pavlushin, A.D., Goryainov, S.V., Afanasiev, V.P., Poikilenko, N.P.Comparative characteristics of diamonds with olivine inclusions from the Ebelyakh placer and kimberlite pipes of the Yakutian Diamondiferous province.Doklady Earth Sciences, Vol. 468, 1, pp. 473-477.RussiaDeposit - Mir, Aykhal, Udachnaya, XXII Congress

Abstract: The results of morphological examination and the character of the structural orientation and estimation of residual pressure calculated from spectra of combination dispersion in olivine inclusions within diamonds of the Ebelyakh placer and kimberlite pipes of the Yakutian Diamondiferous Province are presented. The data analysis aimed at revealing indications of similarity and/or differences between diamonds from the pipes and the placer. Differences in the structural orientation and spectra of combination dispersion of the inclusions of olivine in dodecahedroids of placers of the northeastern part of the Siberian Platform support the assumption of their non-kimberlite nature.
DS201702-0258
2016
Afanasiev, V.P.Zhimulev, E.I., Sonin, V.M., Afanasiev, V.P., Chepuov, A.I., Pokhilenko, N.P.Fe-S melt as a likely solvent of diamond under mantle conditions.Doklady Earth Sciences, Vol. 471, 2, pp. 1277-1279.MantleDiamond morphology

Abstract: The first results of experimental study of diamond dissolution in a S-bearing Fe melt at high P-T parameters are reported and the morphology of partially dissolved crystals is compared with that of natural diamonds. Our results show that under the experimental conditions (4 GPa, 1400°C), flat-faced octahedral diamond crystals are transformed into curve-faced octahedroids with morphological features similar to those of natural diamonds.
DS201705-0892
2017
Afanasiev, V.P.Zhimulev, E.I., Sonin, V.M., Afanasiev, V.P., Chepurov, A.I., Pokhilenko, N.P.Fe-S melt as a likely solvent of diamond under mantle conditions.Doklady Earth Sciences, Vol. 471, 2, pp. 1277-1279.MantleDiamond morphology

Abstract: The first results of experimental study of diamond dissolution in a S-bearing Fe melt at high P-T parameters are reported and the morphology of partially dissolved crystals is compared with that of natural diamonds. Our results show that under the experimental conditions (4 GPa, 1400°C), flat-faced octahedral diamond crystals are transformed into curve-faced octahedroids with morphological features similar to those of natural diamonds.
DS201804-0740
2018
Afanasiev, V.P.Sonin, V.M., Zhimulev, E.I., Pomazanskiy, B.S., Zemnuhov, A.L., Chepurov, A.A., Afanasiev, V.P., Chepurov, A.I.Morphological features of diamond crystals dissolved in Fe0.7 S0.3 melt at 4GPa and 1400.Geology of Ore Deposits, Vol. 60, pp. 82-92.Technologydiamond morphology

Abstract: An experimental study of the dissolution of natural and synthetic diamonds in a sulfur-bearing iron melt (Fe0.7S0.3) with high P-T parameters (4 GPa, 1400°?) was performed. The results demonstrated that under these conditions, octahedral crystals with flat faces and rounded tetrahexahedral diamond crystals are transformed into rounded octahedroids, which have morphological characteristics similar to those of natural diamonds from kimberlite. It was suggested that, taking into account the complex history of individual natural diamond crystals, including the dissolution stages, sulfur-bearing metal melts up to sulfide melts were not only diamond-forming media during the early evolution of the Earth, but also natural solvents of diamond in the mantle environment before the formation of kimberlitic melts.
DS201810-2325
2018
Afanasiev, V.P.Gromilov, S.A., Afanasiev, V.P., Poikhilenko. N.P.Moissanites of the Popigai astrobleme.Doklady Earth Sciences, Vol. 481, 2, pp. 997-999.Russiamoissanite

Abstract: Moissanites were found in tagamites of the Popigai meteorite crater along with impact diamonds. We have studied 55 samples including 49 individual polytypes and six intergrowths. The numbers of 6H, 15R, 4H, 6H/15R, and 6H/4H polytypes are 82, 7, 5, 4, and 2%, respectively. By the assemblage of polytypes, the moissanites of the Popigai astrobleme are distinct from kimberlite moissanites, as well as from synthetic SiC, which is characterized by the absence of the 4H polytype and the presence of more diverse inclusions (including Fe-bearing). The Popigai astrobleme is one of few objects with reliable natural moissanite. Technogenic contamination is excluded, since any researcher can find this mineral in tagamites.
DS201906-1315
2019
Afanasiev, V.P.Litasov, K.D., Kagi, H., Voropaev, S.A., Hirata, T., Ohfuji, H., Ishibashi., Makino, Y., Bekker, T.B., Sevastyanov, V.S., Afanasiev,V.P., Pokhilenko, N.P.Comparison of enigmatic diamonds from the Tolbachik arc volcano ( Kamchatka) and Tibetan ophiolites: assessing the role of contamination by synthetic materials. Gondwana Research, in press available 38p.Russia, Asia, Tibetdeposit - Tolbachik

Abstract: The enigmatic appearance of cuboctahedral diamonds in ophiolitic and arc volcanic rocks with morphology and infrared characteristics similar to synthetic diamonds that were grown from metal solvent requires a critical reappraisal. We have studied 15 diamond crystals and fragments from Tolbachik volcano lava flows, using Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), synchrotron X-ray fluorescence (SRXRF) and laser ablation inductively coupled plasma mass-spectrometry (LA-ICP-MS). FTIR spectra of Tolbachik diamonds correspond to typical type Ib patterns of synthetic diamonds. In TEM films prepared using focused ion beam technique, we find Mn-Ni and Mn-Si inclusions in Tolbachik diamonds. SRXRF spectra indicate the presence of Fe-Ni and Fe-Ni-Mn inclusions with Cr, Ti, Cu, and Zn impurities. LA-ICP-MS data show variable but significantly elevated concentrations of Mn, Fe, Ni, and Cu reaching up to 70?ppm. These transition metal concentration levels are comparable with those determined by LA-ICP-MS for similar diamonds from Tibetan ophiolites. Mn-Ni (+Fe) solvent was widely used to produce industrial synthetic diamonds in the former USSR and Russia with very similar proportions of these metals. Hence, it appears highly probable that the cuboctahedral diamonds recovered from Kamchatka arc volcanic rocks represent contamination and are likely derived from drilling tools or other hard instruments. Kinetic data on diamond dissolution in basaltic magma or in fluid phase demonstrate that diamond does not form under the pressures and temperature conditions prevalent within the magmatic system beneath the modern-day Klyuchevskoy group of arc volcanoes. We also considered reference data for inclusions in ophiolitic diamonds and compared them with the composition of solvent used in industrial diamond synthesis in China. The similar inclusion chemistry close to Ni70Mn25Co5 for ophiolitic and synthetic Chinese diamonds scrutinized here suggests that most diamonds recovered from Tibetan and other ophiolites are not natural but instead have a synthetic origin. In order to mitigate further dubious reports of diamonds from unconventional tectonic settings and source rocks, we propose a set of discrimination criteria to better distinguish natural cuboctahedral diamonds from those produced synthetically in industrial environments and found as contaminants in mantle- and crust-derived rocks.
DS201910-2242
2019
Afanasiev, V.P.Afanasiev, V.P., Nikolenko, E.I., Glushkova, N.V., Zolnikov, I.D.The new Massadou diamondiferous kimberlite field in Guinea.Geology of Ore Deposits, Vol. 61, 4, pp. 92-100.Africa, Guineadeposit - Massadou

Abstract: A new Massadou kimberlite field, was discovered in southeastern Guinea, near the town of Macenta. It consists of 16 poorly diamondiferous kimberlite dikes, ~1 m thick on average. The ore-controlling zone has a width of around 600 m, its orientation corresponds to the K-4 trend after S. Haggerty, and it is quite well detectable in satellite images. A thick laterite weathering profile has developed on the kimberlites. The main indicator minerals are pyrope, chromite, and ilmenite. Ilmenite grains have a zoned structure with a high-Fe core (hemoilmenite) overgrown by a parallel-columnar aggregate of Mg-ilmente rim resulting from interaction of the core phase with kimberlitic melt. The age of kimberlites is estimated as 140-145 Ma by analogy with those in adjacent areas. Dikes occur as an independent form of kimberlite magmatism in the Guinean-Liberian shield, rather than being roots of kimberlite pipes; therefore, the erosion cutout is relatively small and large-scale diamond placers should not be expected.
DS202005-0718
2020
Afanasiev, V.P.Afanasiev, V.P., Pokhilenko, N.P., Egorova, E.O., Lindenblot, E.S.The most ancient diamond crystals of the Siberian platform. Lamproites Morgogor Creek .. Ebelyakh River.Doklady Earth Sciences, Vol. 489, 2, pp. 1409-1412. pdf Russia, Siberiadiamond alluvials

Abstract: Based on a study of diamond grains from placers of the northeastern Siberian Platform, it is shown that certain types of diamonds (rounded dodecahedroids, diamonds of the II and V?VII varieties, according to the classification by Yu.L. Orlov) could have originated from Precambrian sources. “Ancient” diamonds also differ in terms of their sedimentological history: those of varieties V?VII, despite the maximum abrasion resistance, have the maximum degree of rounding, reflecting their more long-term sedimentological history, and, therefore, their ore bodies were likely the most ancient.
DS202006-0908
2020
Afanasiev, V.P.Afanasiev, V.P., Pokhilenko, N.P., Grinenko, V.S., Kostin, A.V., Malkovets, V.G., Oleinikov, O.B.Kimberlitic magmatism in the south western flank of the Vilui basin. ( pyrope from Kenkeme River catchment) Jurassic-Cretaceous barren kimberlites.Doklady Earth Science, Vol. 490, 2, pp. 51-54.Russiageochronology

Abstract: We have analyzed 141 grains of pyrope from Neogene sediments in a quarry of construction materials, in the Kenkeme River catchment, along its left-side tributary (Chakiya River), about 60 km northwest of Yakutsk city. The mineral chemistry patterns of pyropes are typical of Jurassic-Cretaceous barren kimberlites, like the pipes of Obnazhennaya or Muza, but are uncommon to diamondiferous Middle Paleozoic kimberlites. The results allow identifying the magmatic event and placing time constraints on kimberlite magmatism in the southeastern flank of the Vilui basin, which was part of the Late Jurassic-Early Cretaceous tectonic-magmatic event in northeastern Asia.
DS202011-2029
2001
Afanasiev, V.P.Ashchepkov, I.V., Afanasiev, V.P., Pokhilenko, N.P., Sobolev, N.V., Vladykin, N.V., Saprykin, A.I., Khmelnikova, O.S., Anoshin, G.N.Small note on the composition of Brazilian mantle. *** NOTE DATERevista Brasileira de Geociencas*** ENG, Vol. 31, 4, pp. 653-660. pdfSouth America, Brazilkimberlites

Abstract: Garne ts from couc eru ratc from the vargcm l kimberl ite pipe show a long compos itional range and reveallong lincar tre nds within the lherzolite field in a Cr~Ol - CaO% dia gram (Sobolcv et til. 1974) (lip (0 11% MgO). fon ned by grains of different dimensions with fcw deviations to harzburg itcs . Larger grains (fraction +3) arc higher in CaO with less Cr~01 (to 5.5%). TIle Cr20 1 freq uen cy reduc es in hyperbo lic function for each fraction . IImenites reve;1142-56% Ti0 2l..'Olllpositionai range with linear FeO - MgO correhuions but 3(4) separate groups for A I ~01 suggest different proport ion of co-prccipimted gimlet , probably due to polybn ric Irncnonanon. lncreasing Cr~O l nnd r"t..-Q% conte nt (fractionation uegn:e ) with red ucing TiO~ is in accord with Ar c mod el.. Ganict xenolith fnnnldnin II pipe with large Ga r- Cpxgrains and fine Mica-Curb bearing mat rix refer to 60 kbcr and 35 mv/m2 gcothcrm . 11displays enr iched trace c lement pat ter ns but not completely equilibrated compositions for Ga r anti Cpx. sugges ting low degree me lting of rela tively fertile mantle. St udied uuuc rinlmay s uggcsrmcrasomu tized, relat ively fertile and irre gularly heated mantle bene ath Sombcrn Bra zil as found by (Carvalho & Lccnnrdos 1997).
DS202104-0563
2020
Afanasiev, V.P.Afanasiev, V.P., Pohilenko, N.P., Kuligin, S.S., Samdanov, D.A.On the prospects of diamond content of the southern side of the Vilyui syneclise. ( Lena River)Geology of Ore Deposits, Vol. 62, 6, pp. 535-541.RussiaIndicator minerals

Abstract: The paper describes indicator minerals of kimberlites found on the southern side of the Vilyui syneclise in the Markha River basin, a tributary of the Lena River. It is shown that indicator minerals-pyrope and picroilmenite-derive from Middle Paleozoic kimberlites, very likely diamondiferous. Methods are proposed for further studies on determining the prospects for the diamond content of the southern side of the Vilyui syneclise and the northern slope of the Aldan anteclise.
DS202104-0609
2020
Afanasiev, V.P.Sonin, V.M., Zhimulev, E.I., Chepurov, A.A., Lindenblot, E.S., Loginova, A.M., Shcheglov, D.V., Pomazanskii, B.S., Afanasiev, V.P., Chepurov, A.I.Dissolution of natural octahedral diamonds in an Fe-S melt at high pressure.Geology of Ore Deposits, Vol. 62, 6, pp. 497-507. pdfRussia, Yakutiadeposit Yubileinaya

Abstract: An experimental study was carried out on the dissolution of natural octahedral diamonds from the Internatsionalnaya and Yubileinaya kimberlite pipes (Yakutia) in an Fe-S melt at 4 GPa and 1450-1500°C with different sulfur contents (10-25 wt %). It was found that with an increase in sulfur content in the iron melt, the degree of diamond dissolution sharply decreases. The stationary (final) shape of diamond crystal dissolution under the achieved conditions corresponds to an octahedroid with trigonal etching layers, which is confirmed by photogoniometry. Diamonds with similar morphology are common in kimberlite pipes, especially in mantle xenoliths from kimberlites. It was concluded that diamonds with this shape did not undergo natural dissolution in a kimberlite magma, but, similar to flat-faced octahedra, were probably isolated from it in xenoliths. Therefore, the higher the content of octahedroid-shaped diamonds with trigonal layers in a deposit, the smaller the direct influence of an aggressive kimberlite magma on the diamond content.
DS1986-0263
1986
Afanasjev, V.P.Garanin, V.K., Kudryavtseva, G.P., Posukhova, T.V., Afanasjev, V.P.Morphology of kimberlite minerals: its usage for predicting and searchingfor diamond depositsProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 457-459RussiaDiamond exploration
DS201803-0431
2017
Afanasyev, A.A.Afanasyev, A.A., Belyaeva, E.A.The stability of serpentization due to water flow in kimberlite.Journal of Appled Mathematics and Mechanics, Vol. 81, pp. 206-213.Russiadeposit - Mir

Abstract: A linear analysis of the stability of the course of serpentization, that is, of the exothermic hydration reaction, due to the flow of water in a kimberlite pipe is carried out, taking both the heat conduction and the convective heat transfer by the fluid saturating the pipe rocks into account. It is shown that two different serpentization processes exist: a homogeneous process and an inhomogeneous process associated with a loss of stability by the homogeneous process and a non-uniform reaction rate distribution. Dimensionless similarity parameters that determine the course of the reaction are proposed. It is shown that convective heat transfer promotes a stabilization of the flow and the formation of a homogeneous serpentinite distribution. Other conditions being equal, an increase in the convective heat flux leads to an increase in the wavelengths of the unstable perturbations and to a decrease in their amplitude. A critical value of the flow rate exists, and, when this is exceeded, instability does not develop and serpentinization takes place under homogeneous conditions.
DS1960-1058
1969
Afanasyev, G.D.Afanasyev, G.D., et al.Eclogite of the Front Range, Northern CaucasusDoklady Academy of Science USSR, Earth Science Section., Vol. 187, No. 1-6, PP. 164-166.RussiaKimberlite
DS201312-0995
2013
Afanasyev, V.Yelisseyev, A., Meng, G.S., Afanasyev, V., Pokhilenko, N., Pustovarov, V., Isakova, A., Lin, Z.S, Lin, H.Q.Optical properties of impact diamonds from the Popigai astroblemes.Diamond and Related Materials, Vol. 37, pp. 8-16.Russia, SiberiaMeteortic diamonds
DS1970-0859
1974
Afanasyev, V.P.Afanasyev, V.P., Ivaniv, I.N., Koptil, V.I., Kharkiv, A.D.Typomorphism of Diamonds from Kimberlite Veins and the Possible Bed Rock Sources of Diamond Bearing Placers in Northwestern Yakutia.Doklady Academy of Science USSR, Earth Science Section., Vol. 214, No. 1-6, PP. 154-157.Russia, West Africa, GuineaMineralogy, Genesis
DS1981-0002
1981
Afanasyev, V.P.Afanasyev, V.P., et al.On the In homogeneity of Chrome Bearing Ilmenite from the Zimnyaya Kimberlite Pipe and its Genetic Significance.Geol. Rudn. Mestorozhd., Vol. 23, No. 2, PP. 44-57.RussiaPetrography
DS1986-0002
1986
Afanasyev, V.P.Afanasyev, V.P.The mechanical wear of kimberlite minerals as shown by thinsections.(Russian)Soviet Geology (Russian), No. 10, pp. 81-87RussiaWeathering, Kimberlite
DS1986-0003
1986
Afanasyev, V.P.Afanasyev, V.P., Gerasimov, A.Yu., Babenko, V.V.Self-limitation of picroilmenite during reduction processes as a resultof anistropy of the mechanicalproperties.(Russian)In: Mineralogical crystallography and its application to mineral, pp. 159-163RussiaMineralogy, Picroilmenite
DS1986-0004
1986
Afanasyev, V.P.Afanasyev, V.P., Sibertsev, Y.M., Yegorov, A.Y.Minerals from kimberlites in ancient littoral reservoir rocks. (Russian)Izv. Vysshikh Uchn. Zaved. Geol. I Razveda (Russian), Vol. 2, pp. 48-54RussiaPetrology, Mineral chemistry
DS1986-0435
1986
Afanasyev, V.P.Kharkiv, A.D., Afanasyev, V.P., Zinchuk, N.N.Mineralogical mapping of potential diamond territories; basic method For the exploration of diamond deposits.(Russian)In: Mineralogical crystallography and its application mineral, pp. 30-37RussiaOre guides
DS1987-0417
1987
Afanasyev, V.P.Lipitova, V.A., Afanasyev, V.P.Mineralogic and playnologic proof of the Pre-middle Carboniferous age of intermediate kimberlitic mineral reservoirs in the northern part of the MalayaDoklady Academy of Science USSR, Earth Science Section, Vol. 288, No. 1-6, pp. 102-105RussiaBlank
DS1988-0002
1988
Afanasyev, V.P.Afanasyev, V.P., Babenko, V.V.Migration properties of kimberlite mineralsDokl. Acad. Sciences USSR Earth Science Section, Vol. 303, No. 6, pp. 141-144RussiaAlluvials, Modeling, kimberlite miner
DS1988-0003
1988
Afanasyev, V.P.Afanasyev, V.P., Babenko, V.V.Migration properties of kimberlite minerals.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 303, No. 3, pp. 714-718RussiaMineralogy, Migration
DS1988-0708
1988
Afanasyev, V.P.Tsyganov, V.A., Zincguk, N.N., Afanasyev, V.P.Problem of evaluating a general population from non-random samples (as exemplified by the indicator properties of kimberlites)Doklady Academy of Science USSR, Earth Science Section, Vol. 301, No. 4, July-Aug, pp. 74-78RussiaSampling, Kimberlite minerals
DS1993-0010
1993
Afanasyev, V.P.Afanasyev, V.P., Tsyganov, V.A., Choumirin, K.G.Methods of qualitative and quantitative processing and interpretation of heavy mineral data.Diamonds of Yakutia, Russia, Volume $ 115.00 Can., pp. 53-56.Russia, YakutiaMineralogy, Heavy minerals
DS1994-1654
1994
Afanasyev, V.P.Sobolev, N.V., Afanasyev, V.P., Pokhilenko, N., Kaminsky, F.Pyropes and diamonds from the Algerian SaharaDoklady Academy of Sciences USSR, Vol. 326, Oct. pp. 151-157.AlgeriaAlluvials, Geochemistry -garnets
DS200912-0003
2009
Afanasyev, V.P.Afanasyev, V.P., Agashev, A.M., Orihashi, Y., Pokhilenko, N.P., Sobolev, N.V.Paleozoic U Pb age of rutile inclusions in diamonds of the V-VII variety from placers of the northeast Siberian platform.Doklady Earth Sciences, Vol. 428, 1, pp. 1151-1155.RussiaDiamond inclusions
DS201812-2901
2018
Afanasyev, V.P.Yelisseyev, A.P., Afanasyev, V.P., Gromilov, S.A.Yakutites from the Popigai meteorite crater.Diamond & Related Materials, Vol. 89, pp. 10-17.Russiameteorite

Abstract: For the first time, 60 large diamond aggregates were found inside the Popigai meteorite crater during washing of alluvial deposits along the Dogoi river crossing the crater. These aggregates are similar in appearance to yakutites from the placers of Northern Yakutia (YPY), and we regard them as yakutites from the Popigai crater (YPC). The structure and optical properties of Popigai impact diamonds from the impact melt rocks (tagamites) in the crater (PIDT) and yakutites YPC/YPY were compared in detail. In all these cases, a polycrystalline structure consisting of nanoscale grains of cubic and twinned cubic diamond (lonsdaleite) was found. This is the result of a solid-phase graphite-diamond transition due to an impact event 35?million?years ago. The diamond aggregates show the following features: a red shift of the short-wave edge of the transmission, broadening of the diamond Raman peaks, signals from other diamond polytypes and numerous inclusions of other minerals in the Raman spectra, and a dominant broadband photoluminescence (PL). PL in the N3 system associated with N3V centers in PIDT diamonds indicates a high-temperature annealing of these aggregates with resulting aggregation of impurities during the prolonged cooling of large impact melt pockets and pools. It is assumed that some of the impact diamonds were ejected from the crater during the impact event and experienced rapid cooling. Some of these diamonds fell back into the crater (YPC yakutites), others have been deposited outside the crater and displaced during erosion (YPY yakutites). Difference in size and shape between the PIDTs and yakutites YPC/YPY is due to the difference in size of original graphite flakes or aggregates and/or due to the fundamentally different technologies of diamond extraction.
DS1996-0007
1996
Afanasyev. V.P., et al.Afanasyev. V.P., et al.Relative abrasion resistance of pyrope and picroilmenite, two indicator minerals in kimberlite.Doklady Academy of Sciences, Vol. 342 No. 4, May, pp. 93-97.Russia, AlgeriaGeochemistry, Deposit - Malaya Botuobaya, Kyutyungda, Dyukunnakh
DS2003-1315
2003
Afanesev, V.P.Sonin, V.M., Zhimulev, .I., Chepurov, A.I., Afanesev, V.P., Tomileno, A.A.Etching of diamond crystals in the system silicate melt C O H S fluid under a highGeochemistry International, Vol. 41, 7, pp. 688-93.GlobalDiamond - morphology
DS200412-1881
2003
Afanesev, V.P.Sonin, V.M., Zhimulev, .I., Chepurov, A.I., Afanesev, V.P., Tomileno, A.A.Etching of diamond crystals in the system silicate melt C O H S fluid under a high pressure.Geochemistry International, Vol. 41, 7, pp. 688-93.TechnologyDiamond - morphology
DS200612-0046
2005
AfansievAshchepkov, I.V., Vladykin, Rotman, Afansiev, Loginova, Kuchkin, Palessky, Nikolaeva, Saprykin, AnoshinVariations of the mantle mineralogy and structure beneath Upper - Muna kimberlite field.Problems of Sources of Deep Magmatism and Plumes., pp. 170-187.RussiaMineralogy
DS200812-0051
2008
AfansievAshchepkov, I.V., Pokhilenko, Vladykin, Rotam, Afansiev, Logvinova, Kostrovitsky, Karpenko, KuliginReconstruction of mantle sections beneath Yakutian kimberlite pipes using monomineral thermobaraometry.Geological Society of London, Special Publication, SP 293, pp. 335-352.RussiaGeothermometry
DS200812-0052
2007
AfansievAshchepkov, I.V., Vladykin, Pkhilenko, Logvinova, Palessky, Afansiev, Alymova, Stegnitsky, Khmelnikova RotamanVariations of ilmenite compositions from Yakutian kimberlites and the problem of their origin.Vladykin Volume 2007, pp. 71-89.Russia, YakutiaIlmenite, kimberlite
DS200812-0053
2008
AfansievAshchepkov, Pokhilenko, Vladykon, Loginova, Rotman, Afansiev, Kuligin, Malygina, Alymova, Stegnitsky, KhmetnikovaPlume interaction and evolution of the continental mantle lithosphere.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 104-121.MantlePlume
DS201012-0018
2010
AfansievAshchepkov, I.V., Pokhilenko, Vladykin, Logvinova, Afansiev, Kuligin, Malygina, Alymova, KostrovitskyStructure and evolution of the lithospheric mantle beneath Siberian Craton, theromobarometric study.Tectonophysics, Vol. 485, pp. 17-41.RussiaGeothermometry
DS201012-0017
2010
Afansiev, V.Ashchepkov, I., Pokhienko, N., Afansiev, V., Logvinova, A., Pokhienko, L.I., Ntaflos, Ionov, Kuligin, MityukhinMonomineral thermobarometry for the diamond inclusions from Siberia: genetic links.International Mineralogical Association meeting August Budapest, abstract p. 184.RussiaThermobarometry - Mir, Alakite
DS1994-0957
1994
Afansiev, V.P.Kryuchkov, A.I., Leliukh, M.J., Krasinets, S.S., Afansiev, V.P.Two unusual Paleozoic kimberlite diatremes in the Daldyn-Alakit region Of the Siberian PlatformProceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 34-39.Russia, SiberiaDaldyn-Alakit, Kimberlite diatremes
DS200612-0045
2005
Afansiev, V.P.Ashchepkov, I.V., Vladykin, N.V., Pokhilenko, N.P., Rotman, A.Y., Afansiev, V.P., Logvinova, A.M.Using the monomineral thermobarometry for the reconstruction of the mantle sections.Problems of Sources of Deep Magmatism and Plumes., pp. 210-228.MantleGeothermometry
DS201112-0537
2011
Afansiev, V.P.Kopylova, M.G., Afansiev, V.P., Bruce, L., Ryder, J.Diamondiferous conglomerate preserves evidence for kimberlite and the deep cratonic root of the Mesoarchean southern Superior Craton.Goldschmidt Conference 2011, abstract p.1221.Canada, OntarioWawa
DS201112-0538
2011
Afansiev, V.P.Kopylova, M.G., Afansiev, V.P., Bruce, L.F., Ryder, J.Diamond exploration in orogenic settings: lessons from Wawa metaconglomerate.Yellowknife Geoscience Forum Abstracts for 2011, abstract p. 52-53.Canada, Ontario, WawaHeavy minerals
DS201412-0851
2014
Afansiev, V.P.Smith, E.M., Kopylova, M.G., Frezzotti, M.L., Afansiev, V.P.N-rich fluid inclusions in octahedrally-grown diamond.Earth and Planetary Science Letters, Vol. 393, pp. 39-48.Canada, Ontario, WawaDiamond inclusions
DS201610-1919
2016
Afansiev, V.P.Yelisseyev, A.P., Afansiev, V.P., Panchenko, A.V., Gromilov, S.A., Kaichev, V.V., Sarasev, A.A.Yakutites: are they impact diamonds from the Popigai crater?Lithos, in press available 14p.RussiaImpact diamonds

Abstract: Yakutites are coarse (up to 15 mm or larger) aggregates dispersed for more than 500 km around the Popigai meteorite crater. They share many features of similarity with impact diamonds found inside the crater, in elemental and phase compositions, texture, and optical properties as revealed by X-ray photoelectron spectroscopy, X-ray diffraction, and optical spectroscopy (Raman, absorption, luminescence and microscopic) studies. The N3 vibronic system appearing in the luminescence spectra of Popigai impact diamonds (PIDs) indicates a presence of nitrogen impurity and a high-temperature annealing of diamonds that remained in the crater after solid-phase conversion from graphite. Yakutites lack nitrogen-vacancy centers as signatures of annealing, which may indicate quenching at the time of ejection. Thus, both PIDs and yakutites originated during the Popigai impact event and yakutites were ejected to large distances.
DS1998-1382
1998
Afasev, V.P.Sonin, V.M., Chepurov, A.I., Afasev, V.P., Zinchuk, N.N.The origin of discoid sculptures on diamond crystalsDoklady Academy of Sciences, Vol. 361, No. 5, pp. 635-7.GlobalDiamond morphology
DS1988-0709
1988
Afasyev, P.Tsyganov, V.A., Zinchuk, N.N., Afasyev, P., Ovichinnikov, L.N.Express estimation of open and semi-open regions with complexTheory Practice of Geoch. Explor.Modern Conditions, IV All Union Meet, Vol. 7, pp. 140-141. (Russian)RussiaGeochemistry, Kimberlites
DS1988-0390
1988
Afasyev, V.P.Kvasnitsa, V.N., Krochuk, m V.M., Afasyev, V.P., Tsymbal, Yu.S.Crystal morphology of kimberlite chrome spinel.(Russian)Mineral. Zhurn., (Russian), Vol. 10, No. 3, June pp. 45-51RussiaMineralogy, Spinel
DS1995-0009
1995
Affaton, P.Affaton, P., Trompette, R., Uhlein, A., Boudzoumou, F.The Panafrican Brasiliano Aracuai West Congo fold belt in the framework Of western Gondwana aggregation 600MaGeological Society Africa 10th. Conference Oct. Nairobi, p. 20. AbstractWest Africa, BrazilTectonics, Rodinia Supercontinent
DS1997-0050
1997
Affaton, P.Attoh, K., Dallmeyer, R.D., Affaton, P.Chronology of nappe assembly in the Pan-African Dahomeyide orogen, WestAfrica: evidence from 40 Ar 39Precambrian Research, Vol. 82, No. 1-2, March pp. 153-172West Africa, GhanaGeochronology, Orogeny
DS200712-0242
2006
Affaton, P.Deynoux, M., Affaton, P., Trompette, R., Villeneuve, M.Pan-African tectonic evolution and glacial events registered in Neoproterozoic to Cambrian cratonic and foreland basins of West Africa.Journal of African Earth Sciences, Vol. 46, 5, Dec. pp. 397-426.Africa, West AfricaTectonics
DS201212-0534
2012
Affaton, P.Owona, S., Tichomirowa, M., Ratschbacher, L., Ondoa, J.M., Youmen, D., Pfander, J., Tchoua, F.M., Affaton, P., Ekodeck, G.E.New igneous zircon Pb/Pb and metamorphic Rb/Sr ages in the Yaounde Group, Cameroon, Central Africa): implications for the Central African fold belt evolution close to the Congo Craton.International Journal of Earth Sciences, Vol. 101, 7, pp. 1689-1703.Africa, CameroonGeochronology
DS201212-0535
2012
Affaton, P.Owona, S., Tichomirowa, M., Ratschbacher, L., Ondoa, W.J., Youmen, D., Pfander, J., Tchoua, F.M., Affaton, P., Ekodeck, G.E.New igneous zircon Pb/Pb and metamorphic Rb/Sr ages in the Yaounde Group ( Cameron, Central Africa): implications for the Central African fold belt evolution close to the Congo Craton.International Journal of Earth Sciences, Vol. 101, pp. 1689-1703.Africa, CameroonGeochronology
DS200512-0005
2005
AfgemAfgemThe new Afgem.... overview of company, Rex and three kimberlite mines.Mineweb, August 21, 2p.Africa, South AfricaNews item - Rex
DS1988-0367
1988
Afilaka, J.O.Kogbe, C.A., Afilaka, J.O.Review of Africa's solid mineral resource potentialJournal of African Earth Sciences, Vol. 7, No. 3, pp. 589-600AfricaDiamonds pp. 597-598. chart p. 599, Brief description
DS202202-0223
2021
Afilhado, A.Watremez, L., Leroy, S., d'Acremont, E., Roche, V., Evain, M., Lepretre, A., Verrier, F., Aslanian, D., Dias, N., Afilhado, A., Schnurle, P., Castilla, R., Despinois, F., Moulin, M. The Limpopo magma-rich transform margin, south Mozambique - pt. 1 Insights from deep-structure seismic imaging.Tectonics, e2021TC006915Africa, Mozambiquegeophysics -seismics

Abstract: A variety of structures results from the interplay of evolving far-field forces, plate kinematics, and magmatic activity during continental break-up. The east Limpopo transform margin, offshore northern Mozambique, formed as Africa and Antarctica separated during the mid-Jurassic period break-up of the Gondwana supercontinent. The nature of the crust onshore has been discussed for decades in an effort to resolve issues with plate kinematic models. Two seismic refraction profiles with coincident multichannel seismic reflection profiles allow us to interpret the seismic velocity structures across the margin, both onshore and offshore. These seismic profiles allow us to (a) delineate the major regional crustal domains; (b) identify widespread indications of magmatic activity; and (c) map crustal structure and geometry of this magma-rich transform margin. Careful examination of the profiles allows us to make the following observations and interpretations: (a) on land, continental crust is overlain by a >10-km thick volcano-sedimentary wedge related to an early rifting stage, (b) offshore, thick oceanic crust formed due to intense magmatic activity, and between the two (c) a 50-60-km wide transform zone where the crustal structures are affected by intense magmatic activity and faulting. The prominent presence of intrusive and extrusive igneous units may be attributed to the combination of a deep-seated melting anomaly and a trans-tensional fault zone running through thinned lithosphere that allowed melt to reach the surface. A comparison of the crustal thinning along other transform margins shows a probable dependence with the thermal and/or tectonic history of the lithosphere.
DS201506-0271
2015
Afiri, A.Gueydan, F., Pitra, P., Afiri, A., Poujol, M., Essaifi, A., Paquette, J-L.Oligo-Miocene thinning of the Beni Bousera peridotites and their Variscan crustal host rocks, Internal Rif, Morocco.Tectonics, Vol. 34, pp.1244-1268.Africa, MoroccoPeridotite
DS202112-1925
2021
Afonin, N.Danilov, K., Yakovlev, E., Afonin, N.Study of deep structure of the kimberlite pipe named after M. Lomonosov of the Arkhangelsk diamondiferous province obtained by joint using of passive seismic and radiometric methods.Pure and Applied Geophysics, Vol. 178, 10, pp, 3933-3952.Russia, Arkangelskdeposit - Lomonsov

Abstract: Kimberlite pipes are difficult to investigate due to their vertical orientation, conic shape and diverse physical characteristics and petrological compositions, all of which obstruct the use of magnetic methods, reflection and refraction seismic surveys to examine kimberlite pipes. Wherein the emplacement model for kimberlite pipes has important significance in resource geology and in mine design process. As a result, the development of new methods of investigating kimberlite pipes remains necessary. To that end, because the most stable characteristic of kimberlite pipes is their downward-tapering structure, the pipes can be more effectively examined by using methods offering high resolution and new indicators for prospecting. Herein, we present the results of jointly using passive seismic and radiometric methods to study the structure of a kimberlite pipe and its enclosing environment. In particular, we employed a microseismic sounding method, passive seismic interferometry, the H/V method, gamma spectrometry and emanation mapping to model the kimberlite pipe named after M. Lomonosov of the Arkhangelsk diamondiferous province. The combined use of those methods revealed an ore-controlled fault and probably a supply channel (i.e. dyke). The obtained model is correspondent to drill whole data and includes additional information about the structure and elastic properties of the studied pipe. Amongst its principal benefits, the proposed technique affords the possibility of discerning the primary elements of the kimberlite pipes and enclosing environments at depths from 30 m to 2 km, which can significantly increase the effectiveness of investigations into kimberlite pipes.
DS202102-0210
2021
Afonina, T.B.Mints, M.V., Dokukina, K.A., Afonina, T.B.Precambrian lithosphere beneath Hudson Bay: a new geological model based on the Hudson Bay lithospheric experiment ( HuBLE), Canadian shield.Tectonophysics, Vol. 799, 15p. Doi.org/10.1016/ j.tecto.2020.228701Canada, Ontario, Quebectomography

Abstract: The oval-shaped basin of Hudson Bay occurs near the center of the round-oval Archaean crustal domain of the North American continent. This paper presents models of the geological structure and evolution of the subcontinental lithospheric mantle underlying Hudson Bay and surrounding tectonic provinces based on geological interpretations of regional geological and geophysical data and results of seismic tomography investigations that have been conducted under the Hudson Bay Lithospheric Experiment. The experiment was aimed at lithospheric processes directly related to the origin of the North American craton and the Hudson Bay basin. Hudson Bay is located directly above the lithospheric keel of North America. The geological history demonstrates systematic "renovation" of the basin: (1) origin and evolution of the Neoarchaean Lake Minto basin (~2.75 Ga); (2) accumulation of the Palaeoproterozoic volcanic-sedimentary filling of the epicontinental basin, relics of which is preserved on its passive margins (2.03-1.87 Ga); (3) origin of Ordovician-Late Devonian sedimentary sequence whose maximum thickness reaches 2.5 km; and (4) the development of Late Jurassic-Miocene sediment-filled ring-shaped trough immediately above the lithospheric keel. The Hudson Bay basin occurs above the lithospheric keel in compliance with thermomechanical model of ascending plume. Tomography studies have not detected evidence of either production or transformation of the lithosphere in the Palaeoproterozoic, which are implied by the model of the United Plates of America. Interpretations of tomography data reveal a vertical axial zone in the lithosphere beneath Hudson Bay, which extends from the lithosphere-asthenosphere boundary to the base of the crust or, perhaps, even to the present day surface. The zone is made up of relatively light low-velocity igneous rocks, probably a swarm of kimberlite dikes or pipes. At 2.75 Ga, the North American continent was a single continental mass with Hudson Bay at its center.
DS202205-0672
2022
Afonso, J.Afonso, J., Ben-Mansour, W., O'Reilly, S.Y., Griffin, W.L., Salajeghegh, F., Foley, S., Begg, G., Selway, K., Macdonald, A., Januszczak, N., Fomin, I., Nyblade, A.A., Yang, Y.Thermochemical structure and evolution of cratonic lithosphere in central and southern Africa.Nature Geoscience, Apr. 26, 329p. FreeAfrica, South AfricaCraton

Abstract: The thermochemical structure of the subcontinental mantle holds information on its origin and evolution that can inform energy and mineral exploration strategies, natural hazard mitigation and evolutionary models of Earth. However, imaging the fine-scale thermochemical structure of continental lithosphere remains a major challenge. Here we combine multiple land and satellite datasets via thermodynamically constrained inversions to obtain a high-resolution thermochemical model of central and southern Africa. Results reveal diverse structures and compositions for cratons, indicating distinct evolutions and responses to geodynamic processes. While much of the Kaapvaal lithosphere retained its cratonic features, the western Angolan-Kasai Shield and the Rehoboth Block have lost their cratonic keels. The lithosphere of the Congo Craton has been affected by metasomatism, increasing its density and inducing its conspicuous low-topography, geoid and magnetic anomalies. Our results reconcile mantle structure with the causes and location of volcanism within and around the Tanzanian Craton, whereas the absence of volcanism towards the north is due to local asthenospheric downwellings, not to a previously proposed lithospheric root connecting with the Congo Craton. Our study offers improved integration of mantle structure, magmatism and the evolution and destruction of cratonic lithosphere, and lays the groundwork for future lithospheric evolutionary models and exploration frameworks for Earth and other terrestrial planets.
DS200512-0006
2005
Afonso, J.C.Afonso, J.C., Ranali, G., Fernandez, M.Thermal expansivity and elastic properties of the lithospheric mantle: results from mineral physics of composites.Physics of the Earth and Planetary Interiors, Vol. 149, 3-4, April 15, pp. 279-306.MantleGeothermometry
DS200912-0266
2009
Afonso, J.C.Griffin, W.L., Begg, G., O'Reilly, S.Y., Afonso, J.C.Paleo-Archean generation of the continental lithosphere.Goldschmidt Conference 2009, p. A466 Abstract.MantleKimberlite xenoliths
DS200912-0268
2009
Afonso, J.C.Griffin, W.L., O'Reilly, S.Y., Afonso, J.C., Begg, G.C.The composition and evolution of lithospheric mantle: a re-evaluation and its tectonic implications.Journal of Petrology, Vol. 50,no. 7,. pp. 1185-1204.MantleTectonics
DS201012-0003
2010
Afonso, J.C.Afonso, J.C., Ranalli, G., Fernandez, M., Griffin, W.L., O'Reilly, S.Y., Faul, U.On the VpVs-Mg# correlation in mantle peridotites: implications for the identification of thermal and compositional anomalies in the upper mantle.Earth and Planetary Science Letters, Vol. 289, 3-4, pp. 606-618.MantleChemistry
DS201012-0197
2010
Afonso, J.C.Fernadez, M., Afonso, J.C., Ranalli, G.The deep lithospheric structure of the Namibian volcanic margin.Tectonophysics, Vol.481, 1-4, pp. 68-81.Africa, NamibiaTectonics
DS201112-0481
2011
Afonso, J.C.Jemenez-Munt, I., Fernandez, M., Verges, J., Garcia-Castellanos, D., Fullea, J., Perez-Gussinye, M., Afonso, J.C.Decoupled crust mantle accommodation of Africa-Eurasia convergence in the NW Moroccan margin.Journal of Geophysical Research, Vol. 116, B08403, 12p.Africa, MoroccoGeophysics - density
DS201312-0009
2013
Afonso, J.C.Afonso, J.C., Fullea, J., Connolly, J., Rawlinson, N., Yang, Y., Jones, A.G.Multi observable thermochemical tomography: a new framework in integrated studies of the lithosphere.Goldschmidt 2013, AbstractMantleGeothermometry
DS201606-1090
2016
Afonso, J.C.Griffin, W.L., Afonso, J.C., Belousova, E.A., Gain, S.E., Gong, X-H., Gonzalez-Jiminez, J.M., Howell, D., Huang, J-X., McGowan, N., Pearson, N.J., Satsukawa, T., Shi R., Williams, P., Xiong, Q., Yang, J-S., Zhang, M., O'Reilly, S.Y.Mantle recycling: transition zone metamorphism of Tibetan ophiolitic peridotites and its tectonic implications.Journal of Petrology, in press available, 30p.Asia, China, TibetPeridotite

Abstract: Large peridotite massifs are scattered along the 1500?km length of the Yarlung-Zangbo Suture Zone (southern Tibet, China), the major suture between Asia and Greater India. Diamonds occur in the peridotites and chromitites of several massifs, together with an extensive suite of trace phases that indicate extremely low fO2 (SiC, nitrides, carbides, native elements) and/or ultrahigh pressures (UHP) (diamond, TiO2 II, coesite, possible stishovite). New physical and isotopic (C, N) studies of the diamonds indicate that they are natural, crystallized in a disequilibrium, high-T environment, and spent only a short time at mantle temperatures before exhumation and cooling. These constraints are difficult to reconcile with previous models for the history of the diamond-bearing rocks. Possible evidence for metamorphism in or near the upper part of the Transition Zone includes the following: (1) chromite (in disseminated, nodular and massive chromitites) containing exsolved pyroxenes and coesite, suggesting inversion from a high-P polymorph of chromite; (2) microstructural studies suggesting that the chromitites recrystallized from fine-grained, highly deformed mixtures of wadsleyite and an octahedral polymorph of chromite; (3) a new cubic Mg-silicate, with the space group of ringwoodite but an inverse-spinel structure (all Si in octahedral coordination); (4) harzburgites with coarsely vermicular symplectites of opx + Cr-Al spinel ± cpx; reconstructions suggest that these are the breakdown products of majoritic garnets, with estimated minimum pressures to?>?13?GPa. Evidence for a shallow pre-metamorphic origin for the chromitites and peridotites includes the following: (1) trace-element data showing that the chromitites are typical of suprasubduction-zone (SSZ) chromitites formed by magma mixing or mingling, consistent with Hf-isotope data from magmatic (375?Ma) zircons in the chromitites; (2) the composition of the new cubic Mg-silicate, which suggests a low-P origin as antigorite, subsequently dehydrated; (3) the peridotites themselves, which carry the trace element signature of metasomatism in an SSZ environment, a signature that must have been imposed before the incorporation of the UHP and low-fO2 phases. A proposed P-T-t path involves the original formation of chromitites in mantle-wedge harzburgites, subduction of these harzburgites at c. 375?Ma, residence in the upper Transition Zone for >200 Myr, and rapid exhumation at c. 170-150?Ma or 130-120?Ma. Os-isotope data suggest that the subducted mantle consisted of previously depleted subcontinental lithosphere, dragged down by a subducting oceanic slab. Thermomechanical modeling shows that roll-back of a (much later) subducting slab would produce a high-velocity channelized upwelling that could exhume the buoyant harzburgites (and their chromitites) from the Transition Zone in?
DS201709-1998
2017
Afonso, J.C.Henry, H., Afonso, J.C., Satsukawa, T., Griffin, W.L., O'Reilly, S.Y., Kaczmarek, M-A., Tilhac, R., Gregoire, M., Ceuleneer, G.The unexplored potential impact of pyroxenite layering on upper mantle seismic properties.Goldschmidt Conference, abstract 1p.Europe, Spain, United States, Californiageophysics - seismics

Abstract: It is now accepted that significant volumes of pyroxenites are generated in the subduction factory and remain trapped in the mantle. In ophiolites and orogenic massifs the geometry of pyroxenite layers and their relationships with the host peridotite can be observed directly. Since a large part of what is known about the upper mantle structure is derived from the analysis of seismic waves, it is crucial to integrate pyroxenites in the interpretations. We modeled the seismic properties of a peridotitic mantle rich in pyroxenite layers in order to determine the impact of layering on the seimsic properties. To do so, EBSD data on deformed and undeformed pyroxenites from the Cabo Ortegal complex (Spain) and the Trinity ophiolite (California, USA) respectively are combined with either A or B-type olivine fabrics in order to model a realistic pyroxenite-rich upper mantle. Consideration of pyroxeniterich domains within the host mantle wall rock is incorporated in the calculations using the Schoenberg and Muir group theory [1]. This quantification reveals the complex dependence of the seismic signal on the deformational state and relative abundance of each mineral phase. The incorporation of pyroxenites properties into geophysical interpretations in understanding the lithospheric structure of subduction zones will lead to more geologically realistic models.
DS201801-0017
2017
Afonso, J.C.Giuliani, A., Campeny, M., Kamenetsky, V.S., Afonso, J.C., Maas, R., Melgarejo, J.C., Kohn, B.P., Matchen, E.L., Mangas, J., Goncalves, A.O., Manuel, J.Southwestern Africa on the burner: Pleistocene carbonatite volcanism linked to deep mantle upwelling in Angola.Geology, Vol. 45, 11, pp. 971=974.Africa, Angolacarbonatite - Catanda

Abstract: The origin of intraplate carbonatitic to alkaline volcanism in Africa is controversial. A tectonic control, i.e., decompression melting associated with far-field stress, is suggested by correlation with lithospheric sutures, repeated magmatic cycles in the same areas over several million years, synchronicity across the plate, and lack of clear age progression patterns. Conversely, a dominant role for mantle convection is supported by the coincidence of Cenozoic volcanism with regions of lithospheric uplift, positive free-air gravity anomalies, and slow seismic velocities. To improve constraints on the genesis of African volcanism, here we report the first radiometric and isotopic results for the Catanda complex, which hosts the only extrusive carbonatites in Angola. Apatite (U-Th-Sm)/He and phlogopite 40Ar/39Ar ages of Catanda aillikite lavas indicate eruption at ca. 500-800 ka, more than 100 m.y. after emplacement of abundant kimberlites and carbonatites in this region. The lavas share similar high-? (HIMU)-like Sr-Nd-Pb-Hf isotope compositions with other young mantle-derived volcanics from Africa (e.g., Northern Kenya Rift; Cameroon Line). The position of the Catanda complex in the Lucapa corridor, a long-lived extensional structure, suggests a possible tectonic control for the volcanism. The complex is also located on the Bié Dome, a broad region of fast Pleistocene uplift attributed to mantle upwelling. Seismic tomography models indicate convection of deep hot material beneath regions of active volcanism in Africa, including a large area encompassing Angola and northern Namibia. This is strong evidence that intraplate late Cenozoic volcanism, including the Catanda complex, resulted from the interplay between mantle convection and preexisting lithospheric heterogeneities.
DS202002-0219
2020
Afonso, J.C.Tilhac, R., Oliveira, B., Griffin, W.L., O'Reilly, S.Y., Schaefer, B.F., Alard, O., Ceuleneer, G., Afonso, J.C., Gregoire, M.Reworking of old continental lithosphere: unradiogenic Os and decoupled Hf-Nd isotopes in sub-arc mantle pyroxenites.Lithos, Vol. 354-355, 19p. pdfEurope, Spainpyroxenites

Abstract: Mantle lithologies in orogenic massifs and xenoliths commonly display strikingly different Hf- and Nd-isotope compositions compared to oceanic basalts. While the presence of pyroxenites has long been suggested in the source region of mantle-derived magmas, very few studies have reported their combined HfNd isotope compositions. We here report the first LuHf data along with ReOs data and S concentrations on the Cabo Ortegal Complex, where the pyroxenite-rich Herbeira massif has been interpreted as remnants of a delaminated arc root. The pyroxenites, chromitites and their host harzburgites show a wide range of whole-rock 187Re/188Os and 187Os/188Os (0.16-1.44), indicating that Re was strongly mobilized, partly during hydrous retrograde metamorphism but mostly during supergene alteration that preferentially affected low-Mg#, low Cu/S pyroxenites. Samples that escaped this disturbance yield an isochron age of 838 ± 42 Ma, interpreted as the formation of Cabo Ortegal pyroxenites. Corresponding values of initial 187Os/188Os (0.111-0.117) are relatively unradiogenic, suggesting limited contributions of slab-derived Os to primitive arc melts such as those parental to these pyroxenites. This interpretation is consistent with radiogenic Os in arc lavas being mostly related to crustal assimilation. Paleoproterozoic to Archean Os model ages confirm that Cabo Ortegal pyroxenites record incipient volcanic arc magmatism on the continental margin of the Western African Craton, as notably documented by zircon UPb ages of 2.1 and 2.7 Ga. LuHf data collected on clinopyroxene and amphibole separates and whole-rock samples are characterized by uncorrelated 176Lu/177Hf and 176Hf/177Hf (0.2822-0.2855), decoupled from Nd-isotope compositions. This decoupling is ascribed to diffusional disequilibrium during melt-peridotite interaction, in good agreement with the results of percolation-diffusion models simulating the interaction of an arc melt with an ancient melt-depleted residue. These models notably show that HfNd isotopic decoupling such as recorded by Cabo Ortegal pyroxenites and peridotites (??Hf(i) up to +97) is enhanced during melt-peridotite interaction by slow diffusional re-equilibration and can be relatively insensitive to chromatographic fractionation. Finally, we discuss the hypothesis that arc-continent interaction may provide preferential conditions for such isotopic decoupling and propose that its ubiquitous recognition in peridotites reflects the recycling of sub-arc mantle domains derived from ancient, reworked SCLM.
DS202004-0525
2019
Afonso, J.C.Kumar, A., Fernandez, M., Jimenez-Munt, I., Torne, M., Verges, J., Afonso, J.C.LitMod2D_2.0: an improved integrated geophysical petrological modeling took for the physical interpretation of upper mantle anomalies.Geochemistry, Geophysics, Geosystems, 10.1029/2019GC008777. 19p.Mantlegeophysics

Abstract: LitMod2D integrates geophysical and petrological data sets to produce the thermal, density, and seismic velocity structure of the lithosphere and upper mantle. We present a new LitMod2D_2.0 package with improvements focused on (i) updated anelastic attenuation correction for anharmonic seismic velocities, (ii) chemical composition in the sublithospheric mantle, and (iii) incorporation of sublithospheric mantle anomalies. Sublithospheric mantle anomalies can be defined with different chemical composition, temperature, seismic velocities, and a combination of them, allowing the application of LitMod2D_2.0 to regions affected by mantle upwelling, subduction, delamination, and metasomatism. We demonstrate the potential application of LitMod2D_2.0 to such regions and the sensitivity of thermal and compositional anomalies on density and seismic velocities through synthetic models. Results show nonlinearity between the sign of thermal and seismic velocity anomalies, and that S wave velocities are more sensitive to temperature whereas P wave velocities are to composition. In a synthetic example of subduction, we show the sensitivity of sublithospheric mantle anomalies associated with the slab and the corner flow on surface observables (elevation, geoid height, and gravity anomalies). A new open?source graphic user interface is incorporated in the new package. The output of the code is simplified by writing only the relevant physical parameters (temperature, pressure, material type, density, and seismic velocities) to allow the user using predefined post?processing codes from a toolbox (flexure, mineral assemblages, synthetic passive seismological data, and tomography) or designing new ones. We demonstrate a post?processing example calculating synthetic seismic tomography, Rayleigh surface?wave dispersion curves, and P wave receiver functions from the output file of LitMod2D_2.0.
DS200912-0235
2009
Afonso, L.A.D.Fullea, J.J.C., Afonso, L.A.D., Connolly, M., et al.LitMod3D: an interactive 3-D software to model the thermal, compositional, density, seismological, and rheological structure of the lithosphere and sublithosGeochemistry, Geophysics, Geosystems: G3, Vol. 10, QO8019TechnologyModels
DS1997-0008
1997
Africa FocusAfrica FocusHandbook og African stock exchangesAfrica Focus, $ 40.00 United StatesAfricaLegal - stock exchanges, Book - ad
DS201012-0004
2010
African AnalystAfrican AnalystBreaking the curse... a case for transparent taxation.African Analyst, Vol. 5, 1, pp. 34-52.AfricaEconomics - taxation
DS1994-0013
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentANGOLA. #1African Conference Mining Investment, June 8-9, 32p.AngolaCountry profile, Diamond production
DS1994-0014
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentBOTSWANA, 1994; African Conference Mining InvestmentAfrican Conference Mining Investment, June 8-9, 20p.BotswanaCountry profile, Diamond production
DS1994-0015
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentGHANAAfrican Conference Mining Investment, June 8-9, 36p.GhanaCountry profile, Diamond production
DS1994-0016
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentIVORY COASTAfrican Conference Mining Investment, June 8-9, 10p.GlobalCountry profile, Diamond production
DS1994-0017
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentBURKin a FASO. (in French)African Conference Mining Investment, June 8-9, 13p.GlobalCountry profile, Diamond production
DS1994-0018
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentMali Africa project planned...Niger River south.African Conference Mining Investment, June 8-9, 34p.GlobalCountry profile, Diamond production
DS1994-0019
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentGUINEA. (in French)African Conference Mining Investment, June 8-9, 18p.GuineaCountry profile, Diamond production
DS1994-0020
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentNAMIBIA (1994)African Conference Mining Investment, June 8-9, 4p.NamibiaCountry profile, Diamond production
DS1994-0021
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentSIERRA LEONE 1994African Conference Mining Investment, June 8-9, 18p.Sierra LeoneCountry profile, Diamond production
DS1994-0022
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentTANZANIA (1994)African Conference Mining Investment, June 8-9, 24p.TanzaniaCountry profile, Diamond production
DS1994-0023
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentZAMBIAAfrican Conference Mining Investment, June 8-9, 36p.ZambiaCountry profile
DS1994-0024
1994
African Conference Mining InvestmentAfrican Conference Mining InvestmentZIMBABWEAfrican Conference Mining Investment, June 8-9, 10p.ZimbabweCountry profile, Diamonds
DS2002-0009
2002
African ExchangeAfrican ExchangeTrends in mining laws and regulation among the developing nationsAfrican Exchange, Feb. pp. 53-55.AfricaList of countries, taxes, law, legal
DS1991-1183
1991
Aftab Khan, M.Moon, C.J., Aftab Khan, M.Mineral exploration... review in various countriesMining Annual Review, June 1991, pp. 175-195GlobalMineral exploration, Review 1990
DS1992-0009
1992
Aftab Khan, M.Aftab Khan, M., Maguire, P.K.H., Swain, C.J.Geophysical models of the Kenya riftTectonophysics, Vol. 209, pp. 209-211. Extended abstractEast Africa, KenyaTectonics, Geophysics -gravity, seismics
DS1984-0473
1984
Agafanov, L.V.Makeev, A.B., Agafanov, L.V., Goncharenko, A.I.The Relation of the Chemical Composition to the Physical Properties of Chrome Spinels in Alpinotypic Ultrabasites.Soviet Geology And Geophysics, Vol. 25, No. 2, PP. 125-129.RussiaMineral Chemistry
DS1975-0001
1975
Agafonov, L.V.Agafonov, L.V., et al.Deep Seated Inclusions in Alkalic Basaltoids of the Shavaryin Tsaram Pipe, Mongolian People's Republic.Doklady Academy of Science USSR, Earth Science Section., Vol. 224, No. 1-6, PP. 130-132.RussiaKimberlite, Pyrope
DS201312-0154
2013
Agafonov, L.V.Chepurov, A.I., Zhimulev, E.I., Agafonov, L.V., Sonin, V.M., Chepurov, A.A., Tomilenko, A.A.The stability of ortho- and clinopyroxenes, olivine and garnet in kimberlitic magma.Russian Geology and Geophysics, Vol. 54, 4, pp. 406-415.RussiaMineral chemistry
DS200712-0223
2007
Agafonov, V.Davydov, V.A., Rakhmanina, A.V., Rols, S., Agafonov, V., Pulikkathara, M.X., Wal, R.V., Khabashesku, V.N.Size dependent phase transition of diamond to graphite at high pressures.Journal of Physical Chemistry , Vol. 111, no. 35, pp. 12918-12925. Ingenta 1074185621TechnologyUHP
DS201012-0744
2010
Agakhanov, A.A.Spiridonov, E.M., Paulov, L.A., Sokolova, E.L., Vorobev, E.I., Agakhanov, A.A.Chlorine bearing lizardite from metakimberlite of the Udachanaya East pipe.Doklady Earth Sciences, Vol. 431, 1, pp. 403-405.Russia, YakutiaDeposit - Udachnaya East
DS201904-0763
2019
Agangi, A.Olierook, H.K.H., Agangi, A., Plavsa, D., Reddy, S.M., Yao, W., Clark, C., Occipinti, S.A., Kylander-Clark, A.R.C.Neoproterozoic hydrothermal activity in the west Australian craton related to Rodinia assembly or breakup?Gondwana Research, Vol 68, 1, pp. 1-12.Australiacraton

Abstract: The timing of final assembly and initiation of subsequent rifting of Rodinia is disputed. New rutile ages (913?±?9?Ma, 900?±?8?Ma and 873?±?3?Ma) and published zircon, monazite, titanite, biotite, muscovite and xenotime geochronology from the Capricorn Orogen (West Australian Craton) reveal a significant early Neoproterozoic event characterized by very low to low metamorphic grade, abundant metasomatism, minor leucogranitic and pegmatitic magmatism and NW-SE fault reactivation episodes between ca. 955 and 830?Ma. Collectively, these are termed the ca. 955-830?Ma Kuparr Tectonic Event. An age range of ca. 955-830?Ma is concomitant with the final stages of Rodinia assembly and the initial stages of its attempted breakup. Very low- to low-grade metamorphic and structural geological evidence favor a distal north-south compressional regime as the driver for hydrothermal activity during ca. 955-830?Ma. Nearby continental collision or accretion from the west (e.g., South China and/or Tarim) are ruled out. The cessation of metasomatism and magmatism in the West Australian Craton after ca. 830?Ma is concomitant with the emplacement of the Gairdner-Amata dyke swarm and associated magmatic activity in South China and Laurentia, the inception of the Adelaide Rift Complex and the deposition of the Centralian Superbasin. We posit that the cessation of hydrothermal activity in the Capricorn Orogen was caused by a tectonic switch from compressional to extensional at ca. 830?Ma. Magmatic and hydrothermal fluids were transferred away from the Capricorn Orogen to the incipient Adelaide Rift Complex, terminating metasomatism in the West Australian Craton. Ultimately, the Kuparr Tectonic Event marked the final stages of Rodinia assembly and its cessation marks the initial stages of its attempted breakup.
DS202101-0018
2020
Agangi, A.Humbert, F., Elburg, M.A., Agangi, A., Belyanin, G., Akoh, J., Smith, A.J.B., Chou, Y-M., Beukes, N.J.A ~ 1.4 Ga alkaline mafic sill from the Carletonville area: connection to the Pilanesbeg alkaline province?South African Journal of Geology, Vol. 123, 4, pp. 597-614. pdfAfrica, South Africaalkaline rocks

Abstract: Numerous Mesoproterozoic alkaline intrusions belonging to the Pilanesberg Alkaline Province are present within the Transvaal sub-basin of the Kaapvaal Craton. The Pilanesberg Complex is the best-known example; it represents one of the world’s largest alkaline complexes, and is associated with a northwest-southeast trending dyke swarm that extends from Botswana to the southwest of Johannesburg. This paper documents the results of a petrological and geochemical study of a thin mafic sill (here referred to as an alkaline igneous body, AIB), which intrudes the ca. 2 200 Ma Silverton Formation close to the southernmost part of the Pilanesberg dyke swarm. The AIB has only been observed in cores from a borehole drilled close to Carletonville. It is hypocrystalline, containing randomly oriented elongated skeletal kaersutite crystals and 6 to 8 mm varioles mainly composed of radially oriented acicular plagioclase. These two textures are related to undercooling, probably linked to the limited thickness (70 cm) of the AIB coupled with a probable shallow emplacement depth. Ar-Ar dating of the kaersutite gives an age of ca. 1 400 Ma, similar to the age of Pilanesberg Complex. However, the AIB is an alkaline basaltic andesite and is thus notably less differentiated than the Pilanesberg Complex and some of its associated dykes, such as the Maanhaarrand dyke, for which we provide whole-rock geochemical data. Literature data indicate that the Pilanesberg dyke swarm also contains mafic hypabyssal rocks suggesting a link between the dyke swarm and the AIB. The AIB is characterized by strongly negative ?Nd and ?Hf, that cannot be related to crustal contamination, as shown by positive Ti and P anomalies, and the absence of negative Nb-Ta anomalies in mantle-normalised trace element diagrams. The AIB magma is interpreted to have been derived from a long-lived enriched, probably lithospheric mantle reservoir. The AIB thus provides important information on the magma source of the Pilanesberg Alkaline Province.
DS200712-0003
2007
Agar, B.Agar, B., Coulter, D.Remote sensing for mineral exploration - a decade perspective 1997-2007. ( not specific to diamonds)... good review.Proceedings of Exploration 07 edited by B. Milkereit, pp. 109-136.TechnologyRemote sensing - review
DS1994-0025
1994
Agar, R.A.Agar, R.A.Geoscan airborne multi-spectral scanners as exploration tools for Western Australian diamond and gold deposits.University of Western Australia, Publishing No. 26, pp. 435-447.AustraliaRemote sensing, Deposit -Aries
DS1994-0026
1994
Agar, R.A.Agar, R.A.Geoscan airborne multi-spectral scanners as applied to exploration for western Australian diamond and gold.Tenth Thematic conference on geologic remote sensing, held May, 1994, Vol. 10, pp. II.651-666.AustraliaRemote sensing, Geoscan
DS1990-0846
1990
Agar, S.M.Knipe, R.J., Ritter, E.H., Agar, S.M., Prior, D.J., Law, R.D.Deformation mechanisms, rheology and tectonicsGeological Society of London Special Publication, No. 54, 520pGlobalRock deformation, fracture, faulting, flow mechanisms, Flow laws, rock fabrics, tectonics
DS201412-0003
2014
Agard, P.Agard, P., Zuo, X., Funiciello, F., Bellahsen, N., Faccenna, C., Savva, D.Obduction: why, how and where. Clues from analog models.Earth and Planetary Science Letters, Vol. 393, pp. 132-145.MantleSubduction
DS201812-2772
2018
Agard, P.Agard, P., Plunder, A., Angiboust, S., Bonnet, G., Ruh, J.The subduction plate interface: rock record and mechanical coupling ( from long to short timescales).Lithos, Vol. 320-321, pp. 537-566.Mantlesubduction

Abstract: Short- and long-term processes at or close to the subduction plate interface (e.g.,mineral transformations, fluid release, seismicity and more generally deformation) might be more closely related than previously thought. Increasing evidence from the fossil rock record suggests that some episodes of their long geological evolution match or are close to timescales of the seismic cycle. This contribution uses rocks recovered (episodically) from subduction zones, together with insights from thermomechanical modelling, to provide a new dynamic vision of the nature, structure and properties of the plate interface and to bridge the gap between the mechanical behavior of active subduction zones (e.g.,coupling inferred from geophysical monitoring) and fossil ones (e.g.,coupling required to detach and recover subducted slab fragments). Based on critical observations and an exhaustive compilation of worldwide subducted oceanic units (for which the presence near the plate interface, rock types, pressure, temperature, T/P gradients, thickness and timing of detachment can be assessed), the present study demonstrates how long-term mechanical coupling exerts a key control on detachment from the slab and potential rock recovery. Critical assessment of rock T/P characteristics indicates that these fragments can indeed be used as natural probes and provide reliable information on subduction interface dynamics down to ~2.8?GPa. Rock clusters are identified at depths of 30, 5560 and 80?km, with some differences between rock types. Data also reveal a first-order evolution with subduction cooling (in the first ~5?Myr), which is interpreted as reflecting a systematic trend from strong to weak mechanical coupling, after which subduction is lubricated and mostly inhibits rock recovery. This contribution places bounds on the plate interface constitution, regular thickness (<300?m; i.e. where/when there is no detachment), changing geometry and effective viscosity. The concept of ‘coupled thickness' is used here to capture subduction interface dynamics, notably during episodes of strong mechanical coupling, and to link long- and short-term deformation. Mechanical coupling depends on mantle wedge rheology, viscosity contrasts and initial structures (e.g.,heterogeneous lithosphere, existence of décollement horizons, extent of hydration, asperities) but also on boundary conditions (convergence rates, kinematics), and therefore differs for warm and cold subduction settings. Although most present-day subduction zone segments (both along strike and downdip) are likely below the detachment threshold, we propose that the most favorable location for detachment corresponds to the spatial transition between coupled and decoupled areas. Effective strain localization involves dissolution-precipitation and dislocation creep but also possibly brittle fractures and earthquakes, even at intermediate depths.
DS1984-0394
1984
Agarwal, A.Karkare, S.G., Agarwal, A.The alkalic ultramafic carbonatitic complex of Kala DoohgarKachchh, District Gujrat and the problem of basement toJurassicsIndian Journal of GeocheM., Vol. 1, No. 2, pp. 11-26IndiaCamptonite, Carbonatite
DS1999-0002
1999
Agarwal, B.N.P.Agarwal, B.N.P., Das, L.K., Shaw, R.K.Gravity anomalies, tectonics and ore deposits: a predictive genetic mode lover Aravallis, India.Global Tectonics and Met., Vol. 7, No. 1, Feb. pp. 47-52.IndiaGeophysics - gravity, Model - not specific to diamonds
DS1999-0003
1999
Agarwal, B.N.P.Agarwal, B.N.P., Das, L.K., Shaw, R.K.Tectonics and metallogeny over Central Indian Shield: a geophysicalanalysis.Global Tectonics and Met., Vol. 7, No. 1, Feb. pp. 41-46.IndiaGeophysics - gravity, Tectonics - not specific to diamonds
DS1999-0004
1999
Agarwal, B.N.P.Agarwal, B.N.P., Shaw, R.K.Three dimensional configuration of Moho discontinuity over some parts Of india from gravity field data.Global Tectonics and Met., Vol. 7, No. 1, Feb. pp. 13-14.IndiaLithosphere, Structure - MOHO discontinuty
DS1980-0050
1980
Agarwal, K.Banerjee, P.K., Agarwal, K.History of Diamond Mining With Special Reference to PannaTranscript of Paper From Diamond Seminar, Bombay, 9P.India, Madhya PradeshHistory
DS2002-0010
2002
Agarwal, K.K.Agarwal, K.K., Singh, I.B., Sharma, M., Sharma, S., Rajagopalan, G.Extensional tectonic activity in the cratonward parts ( peripheral bulge) of the Ganga Plain foreland basin, India.International Journal of Earth Sciences, Vol. 91, 5, pp. 897-905.IndiaTectonics - not specific to diamonds
DS1960-0586
1965
Agarwal, M.K.Patel, A.G., Agarwal, M.K.Microstructure of Panna DiamondsAmerican Mineralogist., Vol. 50, No. 1/2, PP. 124-131.India, PannaDiamond Morphology
DS1970-0894
1974
Agarwal, Y.K.Chaudhuri, R., Banerji, K.C., Agarwal, Y.K.The Interactions of Coal and Mica PeridotiteIndia Sci. Congr. 61st. Session Proceedings, No. 3, PP. 147-148.IndiaBlank
DS201312-0006
2013
Agashev, A.Afanasiev, V., Agashev, A., Pokhilenko, N.Dispersion haloes of kimberlite indicator minerals in the Siberian Platform: history and formation conditions.Geology of Ore Deposits, Vol. 55, 4, pp. 256-264.RussiaMineral chemistry
DS201502-0100
2015
Agashev, A.Shchukina, E., Agashev, A., Pokhilenko, N.Multistage metasomatism in lithospheric mantle beneath V. Grib pipe ( Arkhangelsk Diamondiferous province, Russia): evidence from REE patterns in garnet xenocrysts.Economic Geology Research Institute 2015, Vol. 17,, # 1940, 1p. AbstractRussia, Kola Peninsula, ArchangelDeposit - Grib
DS201708-1590
2017
Agashev, A.Agashev, A.Geochemistry of eclogite xenoliths from kimberlite pipe Udachnaya: section of Archean oceanic crust sampled?11th. International Kimberlite Conference, OralRussia, Siberiadeposit - Udachnaya

Abstract: A suite of 17 unique big (1 to 20 kg) and fresh ecligite xenoliths from Udachnaya kimberlite pipe have been studied for their whole-rock and minerals major and trace elements composition.Whole rock major elements composition of the Udachnaya eclogite xenoliths suite have a great variability in their MgO contents (9-19Wt%). Based on major elements composition Udachnaya eclogites can be subdivided in two subsets, high magnesian (Mg# 68.8-81.9) and low magnesian (Mg# 56.8-59). High variations also shown by Al2O3 and Na2O concentrations and high Mg# samples tend to contain less of those oxides then low Mg# samples with some exceptions. Two eclogitic groups are clearly different in style of inter-elements correlations. FeO and CaO contents are positively correlate with MgO in low Mg# group of eclogites but negatively in high Mg# group. The same relations present between Al2O3 contents of eclogite group with their Mg#. Compared to present day MORB composition eclogite samples have similar contents of most of elements with some depletion in TiO2 and P2O5 and enrichment in MgO and K2O. The variability of these elements concentrations can be related to melt extraction while elevated K2O can indicate late metasomatic enrichment. In terms of trace elements composition Udachnaya eclogites are enriched over PM but comparable to that of MORB composition, except significant enrichment in LILE elements (Rb, Ba, K, Sr). The records of both subduction related processes and mantle metasomatism could be find in geochemical features of these rocks. Most of the eclogites show positive Eu anomaly which is direct evidence of plagioclase accumulation in eglogites protolith. Variation of La/Yb ratio (1-11), in majority of samples are the range 2-4 indicates different degrees of samples metasomatic enrichment in LREE. Udachnaya eclogites have range of Sm/Nd ratio from 0.25 to 0.5 (MORB is 0.32) which positive covariates with Nd content. This trend could not be a result of melt extraction nor metasomatic enrichment rather it could reflect heterogeneity of oceanic crust composition and/or mixing with peridotite component during subduction.
DS201708-1591
2017
Agashev, A.Agashev, A.Geochemistry of Mirny field kimberlites, Siberia.11th. International Kimberlite Conference, PosterRussia, Siberiadeposit - Mirny
DS201909-2077
2019
Agashev, A.Pokhilenko, N., Agashev, A., Pokhilenko, L.Features of metasomatic treatment of the lithosphere mantle depleted peridotites in relation with scale and diamond grade of kimberlite magmatism.Goldschmidt2019, 1p. Poster abstractSouth America, Brazildeposit - RosaRio-6

Abstract: Three main cycle of kimberlite magmatism are known for the Siberian Platform (SP) to date: Middle Paleozoic (D3), and two Mesozoic (T2-3 and J3). All economic highgrade kimberlites are of Middle Paleozoic (MP) age, and this feature is related with influence of melts/fluids of Permian-Triassic Siberian Super Plume produced huge changes in structure and composition of the SP Lithospheric Mantle (LM) including its enrichment by basaltic components, thinning, increase of fo2 and resorption of diamonds. Nevertheless, there are incredible differences in amounts of kimberlite bodies and their average diamond grade between different kimberlite fields of MP age, and these features are connected with intensity of carbonatite and silicate types of metasomatic treatment of the most deep-seated SP LM depleted peridotites especially of Lithosphere-Asthenosphere (LA) interaction zone. U-type lithospheric diamond formation is related with initial stage of carbonatite metasomatism, and its increase produce wehrlitezation and then carbonation of initial Cr-pyrope harzburgites and dunites but not related with diamond formation. Minor scale of silicate metasomatism of these modified LM peridotites produced conditions for generation of insignificant amount of kimberlite melts which form kimberlite fields with few bodies, but significant part of them are presented by high-grade kimberlite. And in case of significant scale of both carbonatite and silicate metasomatism of the LM peridotites produce large volume of kimberlite melt and hundreds of kimberlite bodies in fields with minor amonts of high grade ones.
DS1998-0010
1998
Agashev, A.M.Agashev, A.M., Fomin, A.S., Watanabe, T., Pokhilenko, N.Preliminary age determination of recently discovered kimberlites of the Siberian kimberlite province.7th International Kimberlite Conference Abstract, pp. 9-10.Russia, SiberiaGeochronology, Deposit - Sredne-Marxz, Botuobinskaya, Nurbinskaya
DS1998-0011
1998
Agashev, A.M.Agashev, A.M., Watanabe, T., Kuligin, S.S., PokhilenkoStrontium neodymium isotopes in the garnet pyroxenite xenoliths from Siberian kimberlites: a new insight into lithospheric..7th International Kimberlite Conference Abstract, pp. 11-13.Russia, SiberiaGarnet pyroxenite, mantle, Geochemistry
DS2000-0008
2000
Agashev, A.M.Agashev, A.M., Orihashi, Watanabe, Pkhilenko, SerenkoIsotope geochemical features of the Siberian Platform kimberlites in connection with problem of their origin.Russ. Geol. and Geophys., Vol. 41, No. 1, pp. 87-97.Russia, SiberiaGeochemistry, geochronology, Genesis
DS2001-0006
2001
Agashev, A.M.Agashev, A.M., Pokhilenko, McDonald, Takazawa, VavilovA unique kimberlite carbonatite primary association in the Snap lake dyke system: evidence from geochemical..Slave-Kaapvaal Workshop, Sept. Ottawa, 2p. abstractNorthwest TerritoriesGeochemistry, geochronology, Slave Craton, Deposit - Snap Lake
DS2001-0007
2001
Agashev, A.M.Agashev, A.M., Watanabe, Bydaev, Pokhilenko, FominGeochemistry of kimberlites from the Nakyn field, Siberia: evidence for unique source composition.Geology, Vol. 29, No. 3, Mar. pp. 267-70.Russia, SiberiaGeochronology, geochemistry
DS2001-0008
2001
Agashev, A.M.Agashev, A.M., Watanabe, T., Kuligin, S.S., PokhilenkoRubidium-Strontium and Samarium-neodymium isotopes in garnet pyroxenite xenoliths from Siberian kimberlites: an insight into lith. mantleJournal of Mineralogy and Petrology. Sciences, Vol. 96, No. 1, pp. 7-18.Russia, SiberiaGeochronology, Lithospheric - xenoliths
DS2003-1090
2003
Agashev, A.M.Pokhilenko, N.P., Agashev, A.M., McDonald, J.A., Sobolev, N.V., MityukhinKimberlites of the Nakyn field, Siberia and the Snap Lake King Lake dyke system8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractNorthwest TerritoriesDeposit - Snap Lake, King Lake
DS2003-1091
2003
Agashev, A.M.Pokhilenko, N.P., Agashev, A.M., McDonald, J.A., Vavilov, M.A., Clark, D.B..Kimberlites and carbonatites of the Snap Lake King Lake dyke system: structural8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractNorthwest TerritoriesDeposit - Snap Lake, King Lake
DS200412-1561
2003
Agashev, A.M.Pokhilenko, N.P., Agashev, A.M., McDonald, J.A., Sobolev, N.V., Mityukhin, S.I., Vavilov, M.A., Yanygin, Y.T.Kimberlites of the Nakyn field, Siberia and the Snap Lake King Lake dyke system, Slave Craton, Canada: a new variety of kimberli8 IKC Program, Session 7, POSTER abstractCanada, Northwest TerritoriesKimberlite petrogenesis Deposit - Snap Lake, King Lake
DS200412-1562
2003
Agashev, A.M.Pokhilenko, N.P., Agashev, A.M., McDonald, J.A., Vavilov, M.A., Clark, D.B., Wright, K.J.Kimberlites and carbonatites of the Snap Lake King Lake dyke system: structural setting, petrochemistry and petrology of a uniqu8 IKC Program, Session 7, POSTER abstractCanada, Northwest TerritoriesKimberlite petrogenesis Deposit - Snap Lake, King Lake
DS200512-0007
2004
Agashev, A.M.Agashev, A.M., Pokhilenko, N.P., Tolstov, A.V., Polyanichko, Malkovets, SobolevNew age dat a on kimberlites from the Yakutian Diamondiferous Province.Doklady Earth Sciences, Vol. 399, 8, pp.1142-1145.Russia, YakutiaGeochronology
DS200612-0004
2006
Agashev, A.M.Agashev, A.M., Pokhilenko, N.P., Malkovets, V.G., Sobolev, N.V.Sm Nd isotopic system in garnet megacrysts from the Udachnaya kimberlite pipe (Yakutia) and petrogenesis of kimberlites.Doklady Earth Sciences, Vol. 407A, 3, pp. 491-494.Russia, YakutiaGeochronology - Udachnaya
DS200812-0003
2008
Agashev, A.M.Agashev, A.M., Kuligan, S.S., Orihashi, Y., Pokhilenko, N.P., Vavilov, M.A., Clarke, D.Ages of zircons from Jurassic sediments of Bluefish River slope, NWT and the possible age of kimberlite activity in the Lena West property.Doklady Earth Sciences, Vol. 421, 1, pp. 751-754.Canada, Northwest TerritoriesDeposit - Lena West, geochronology
DS200812-0004
2008
Agashev, A.M.Agashev, A.M., Pokhilenko, N.P., Takazawa, E., McDonald, J.A., Vavilov, M.A., Watanabe, T., Sobolev, N.V.Primary melting sequence of a deep ( >250 km) lithospheric mantle as recorded in the geochemistry of kimberlite carbonatite assemblages, Snap Lake dyke system, Canada.Chemical Geology, Vol. 255, 3-4, pp. 317-328.Canada, Northwest TerritoriesDeposit - Snap Lake
DS200912-0003
2009
Agashev, A.M.Afanasyev, V.P., Agashev, A.M., Orihashi, Y., Pokhilenko, N.P., Sobolev, N.V.Paleozoic U Pb age of rutile inclusions in diamonds of the V-VII variety from placers of the northeast Siberian platform.Doklady Earth Sciences, Vol. 428, 1, pp. 1151-1155.RussiaDiamond inclusions
DS201012-0005
2010
Agashev, A.M.Agashev, A.M., Pokhilenko, N.P., Cherepanova, Yu.V., Golovin, A.V.Geochemical evolution of rocks at the base of the lithospheric mantle: evidence from study of xenoliths of deformed peridotites from kimberlite of UdachnayaDoklady Earth Sciences, Vol. 432, 2, pp. 746-749.RussiaDeposit - Udachnaya
DS201112-1063
2011
Agashev, A.M.Tychkov, N.S., Agashev, A.M., Pokhilenko, N.P., Bzhan, I.S.Estimation of the refertilization grade of lithosphere roots by the chemical composition of garnets from Siberian kimberlites.Doklady Earth Sciences, Vol. 439, 2, pp.1175-1178.Russia, SiberiaGeochemistry - garnets
DS201212-0005
2012
Agashev, A.M.Agashev, A.M., Ionov, D.A., Pokhilenko, N.P., Golovin, A.V., Surgutonova, E.A., Sharygin, I.S.Metasomatism in cratonic mantle root: insight from geochemistry of deformed peridotite xenoliths of Udachnaya pipe.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Udachnaya
DS201212-0006
2012
Agashev, A.M.Agashev, A.M., Orihashi, Y., Rotman, A.Ua., Pokhilenko, N.P., erov, I.V., Tolstov, A.V.Rutile and titanite as the minerals for dating kimberlite emplacement age: an example of Amakinskaya and Taezhnaya pipes of Mirny field, Siberia10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Mirny field
DS201212-0562
2012
Agashev, A.M.Pokhilenko, N.P., Afanasev, V.P., McDonald, J.A., Vavilov, M.A., Kulgin, S.S., Pokhilenko, L.N., Golovin, A.V., Agashev, A.M.Kimberlite indicator minerals in terrigene sediments of lower part of Mackenzie River Basin, NWT, Canada: evidence of new craton with thick lithosphere.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Northwest TerritoriesGeochemistry - KIMS
DS201212-0739
2012
Agashev, A.M.Tychkov, N.S., Agashev, A.M., Pokhilenko, N.P.Refertilisation grade estimations of lithosphere roots by the chemical composition of garnets from Siberian kimberlites.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, SiberiaGarnet
DS201312-0010
2013
Agashev, A.M.Agashev, A.M., Ionov, D.A., Pkhilenko, N.P., Golovin, A.V., Cherepanova, Yu., Sharygin, I.S.Metasomatism in lithospheric mantle roots: constraints from whole rock and mineral chemical composition of deformed peridotite xenoliths from kimberlite pipe Udachnaya.Lithos, Vol. 160-161, pp. 201-215.Mantle, Russia, SiberiaDeposit - Udachnaya
DS201312-0045
2013
Agashev, A.M.Ashchepkov, I.V., Ntaflos, T., Kuligin, S.S., Malygina, E.V., Agashev, A.M., Logvinova, A.M., Mitukhin, S.I., Vladykin, N.V.Deep seated xenoliths from the brown breccia of the Udachnaya pipe, Siberia.Proceedings of the 10th International Kimberlite Conference, Vol. 1, Special issue of the Journal of Geological Society of India, Vol. 1, pp. 59-73.RussiaDeposit - Udachnaya
DS201412-0022
2014
Agashev, A.M.Ashchepkov, I.V., Vladykin, N.N., Ntaflos, T., Kostrovitsky, S.I., Prokopiev, S.A., Downes, H., Smelov, A.P., Agashev, A.M., Logvinova, A.M., Kuligin, S.S., Tychkov, N.S., Salikhov, R.F., Stegnitsky, Yu.B., Alymova, N.V., Vavilov, M.A., Minin, V.A., BabusLayering of the lithospheric mantle beneath the Siberian Craton: modeling using thermobarometry of mantle xenolith and xenocrysts. Tectonophysics, Vol. 634, 5, pp. 55-75.Russia, YakutiaDaldyn, Alakit, Malo-Botuobinsky fields
DS201412-0373
2014
Agashev, A.M.Howarth, G.H., Barry, P.H., Pernet-Fisher, J.F., Baziotis, I.P., Pokhilenko, N.P., Poikhilenko, L.N., Bodnar, R.L., Taylor, L.A., Agashev, A.M.Superplume metasomatism: evidence from Siberian mantle xenoliths.Lithos, Vol. 184-187, pp. 209-224.RussiaMetasomatism
DS201412-0695
2014
Agashev, A.M.Poikhilenko, N.P., Afanasiev, V.P., Agashev, A.M., Malkovets, V.G., Poikhilenko, L.N.New archean terranes with thick lithosphere of arctic regions of Siberia and North American ancient platforms: are they prospective for Diamondiferous kimberlites?30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, Russia, CanadaKimberlite
DS201412-0718
2014
Agashev, A.M.Ragozin, A.L., Zedgenizov, D.A., Shatskii, V.S., Orihashi, Y., Agashev, A.M., Kagi, H.U Pb age of rutile from the eclogite xenolith of the Udachnaya kimberlite pipe.Doklady Earth Sciences, Vol. 457, 1, pp. 861-864.Russia, YakutiaDeposit - Udachnaya
DS201412-0937
2014
Agashev, A.M.Tychkov, N.S., Agashev, A.M., Malygina, E.V., Nikolenko, E.I., Pokhilenko, N.P.Thermal pertubations in the lithospheric mantle as evidenced from P-T equilibrium conditions of xenoliths from the Udachnaya kimberlite pipe.Doklady Earth Sciences, Vol. 454, 1, pp. 84-88.Russia, YakutiaDeposit - Udachnaya
DS201412-1013
2014
Agashev, A.M.Yudin, D.S., Tomilenko, A.A., Travin, A.V., Agashev, A.M., Pokhilenko, N.P., Orihashi, yu.The age of the Udachnaya-East kimberlite: U/Pb and 40 Ar/39Ar data.Doklady Earth Sciences, Vol. 455, 1, pp. 288-290.RussiaDeposit - Udachnaya
DS201502-0091
2015
Agashev, A.M.Poikilenko, N.P., Agashev, A.M., Litasov, K.D., Pokhilenko, L.N.Carbonatite metasomatism of peridotite lithospheric mantle: implications for diamond formation and carbonatite-kimberlite magmatism.Russian Geology and Geophysics, Vol. 56, 1, pp. 280-295.MantleCarbonatite
DS201504-0183
2015
Agashev, A.M.Barry, P.H., Hilton, D.R., Day, J.M.D., Pernet-Fisher, J.F., Howarth, G.H., Magna, T., Agashev, A.M., Pokhilenko, N.P., Opkhilenko, L.N., Taylor, L.A.Helium isotope evidence for modification of the cratonic lithosphere during the Permo-Triassic Siberian flood basalt event.Lithos, Vol. 216-217, pp. 73-80.Russia, SiberiaDeposit - Udachnaya, Obnazhennaya

Abstract: Major flood basalt emplacement events can dramatically alter the composition of the sub-continental lithospheric mantle (SCLM). The Siberian craton experienced one of the largest flood basalt events preserved in the geologic record — eruption of the Permo-Triassic Siberian flood basalts (SFB) at ~250 Myr in response to upwelling of a deep-rooted mantle plume beneath the Siberian SCLM. Here, we present helium isotope (3 He/ 4 He) and concentra-tion data for petrologically-distinct suites of peridotitic xenoliths recovered from two temporally-separated kim-berlites: the 360 Ma Udachnaya and 160 Ma Obnazhennaya pipes, which erupted through the Siberian SCLM and bracket the eruption of the SFB. Measured 3 He/ 4 He ratios span a range from 0.1 to 9.8 R A (where R A = air 3 He/ 4 He) and fall into two distinct groups: 1) predominantly radiogenic pre-plume Udachnaya samples (mean clinopyroxene 3 He/ 4 He = 0.41 ± 0.30 R A (1?); n = 7 excluding 1 outlier), and 2) 'mantle-like' post plume Obnazhennaya samples (mean clinopyroxene 3 He/ 4 He = 4.20 ± 0.90 R A (1?); n = 5 excluding 1 outlier). Olivine separates from both kimberlite pipes tend to have higher 3 He/ 4 He than clinopyroxenes (or garnet). Helium con-tents in Udachnaya samples ([He] = 0.13–1.35 ?cm 3 STP/g; n = 6) overlap with those of Obnazhennaya ([He] = 0.05–1.58 ?cm 3 STP/g; n = 10), but extend to significantly higher values in some instances ([He] = 49– 349 ?cm 3 STP/g; n = 4). Uranium and thorium contents are also reported for the crushed material from which He was extracted in order to evaluate the potential for He migration from the mineral matrix to fluid inclusions. The wide range in He content, together with consistently radiogenic He-isotope values in Udachnaya peridotites suggests that crustal-derived fluids have incongruently metasomatized segments of the Siberian SCLM, whereas high 3 He/ 4 He values in Obnazhennaya peridotites show that this section of the SCLM has been overprinted by Permo-Triassic (plume-derived) basaltic fluids. Indeed, the stark contrast between pre-and post-plume 3 He/ 4 He ra-tios in peridotite xenoliths highlights the potentially powerful utility of He-isotopes for differentiating between various types of metasomatism (i.e., crustal versus basaltic fluids).
DS201507-0336
2015
Agashev, A.M.Shchukina, E.V., Agashev, A.M., Golovin, N.N., Pokhilenko, N.P.Equigranualr eclogites from the V. Grib kimberlite pipe: evidence for Paleoproterozoic subduction on the territory of the Arkangelsk Diamondiferous province.Doklady Earth Sciences, Vol. 462, 1, pp. 497-501.Russia, Archangel, Kola PeninsulaDeposit - Grib
DS201602-0237
2015
Agashev, A.M.Shchukina, E.V., Agashev, A.M., Kostrovitsky, S.I., Pokhilenko, N.P.Metasomatic processes in the lithospheric mantle beneath the V. Grib kimberlite pipe ( Arkangelsk Diamondiferous province, Russia).Russian Geology and Geophysics, Vol. 56, pp. 1701-1716.RussiaDeposit - Grib

Abstract: New data on metasomatic processes in the lithospheric mantle in the central part of the Arkhangelsk diamondiferous province (ADP) are presented. We studied the major- and trace-element compositions of minerals of 26 garnet peridotite xenoliths from the V. Grib kimberlite pipe; 17 xenoliths contained phlogopite. Detailed mineralogical, petrographic, and geochemical studies of peridotite minerals (garnet, clinopyroxene, and phlogopite) have revealed two types of modal metasomatic enrichment of the lithospheric-mantle rocks: high temperature (melt) and low-temperature (phlogopite). Both types of modal metasomatism significantly changed the chemical composition of the peridotites. Low-temperature modal metasomatism manifests itself as coarse tabular and shapeless phlogopite grains. Two textural varieties of phlogopite show significant differences in chemical composition, primarily in the contents of TiO2, Cr2O3, FeO, Ba, Rb, and Cs. The rock-forming minerals of phlogopite-bearing peridotites differ in chemical composition from phlogopite-free peridotites, mainly in higher FeO content. Most garnets and clinopyroxenes in peridotites are the products of high-temperature mantle metasomatism, as indicated by the high contents of incompatible elements and REE pattern in these minerals. Fractional-crystallization modeling gives an insight into the nature of melts (metasomatic agents). They are close in composition to picrites of the Izhmozero field, basalts of the Tur’ino field, and carbonatites of the Mela field of the ADP. The REE patterns of the peridotite minerals make it possible to determine the sequence of metasomatic enrichment of the lithospheric mantle beneath the V. Grib kimberlite pipe.
DS201606-1095
2016
Agashev, A.M.Ilyina, O.V., Tychkov, N.S., Agashev, A.M., Golovin, A.V., Izokh, A.E., Kozmenko, O.A., Poikilanko, N.P.PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe ( Yakutia).Doklady Earth Sciences, Vol. 467, 2, pp. 408-411.Russia, YakutiaDeposit - Udachnaya

Abstract: The results of the first study of the PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe (Yakutia) are presented here. The complex character of evolution of the PGE composition in the Deformed lherzolites is assumed to be the result of silicate metasomatism. At the first stage, growth in the amount of clinopyroxene and garnet in the rock is accompanied by a decrease in the concentration of the compatible PGE (Os, Ir). During the final stage, the rock is enriched with incompatible PGE (Pt, Pd) and Re possible due to precipitation of submicron-sized particles of sulfides in the interstitial space of these mantle rocks.
DS201612-2336
2016
Agashev, A.M.Shchukina, E.V., Agashev, A.M., Pokhilenko, N.P.Metasomatic origin of garnet xenocrysts from the V. Grib kimberlite pipe, Arkhangelsk region, NW Russia.Geoscience Frontiers, in press availableRussia, Archangel, Kola PeninsulaDeposit - Grib

Abstract: This paper presents new major and trace element data from 150 garnet xenocrysts from the V. Grib kimberlite pipe located in the central part of the Arkhangelsk diamondiferous province (ADP). Based on the concentrations of Cr2O3, CaO, TiO2 and rare earth elements (REE) the garnets were divided into seven groups: (1) lherzolitic “depleted” garnets (“Lz 1”), (2) lherzolitic garnets with normal REE patterns (“Lz 2”), (3) lherzolitic garnets with weakly sinusoidal REE patterns (“Lz 3”), (4) lherzolitic garnets with strongly sinusoidal REE patterns (“Lz 4”), (5) harzburgitic garnets with sinusoidal REE patterns (“Hz”), (6) wehrlitic garnets with weakly sinusoidal REE patterns (“W”), (7) garnets of megacryst paragenesis with normal REE patterns (“Meg”). Detailed mineralogical and geochemical garnet studies and modeling results suggest several stages of mantle metasomatism influenced by carbonatite and silicate melts. Carbonatitic metasomatism at the first stage resulted in refertilization of the lithospheric mantle, which is evidenced by a nearly vertical CaO-Cr2O3 trend from harzburgitic (“Hz”) to lherzolitic (“Lz 4”) garnet composition. Harzburgitic garnets (“Hz”) have probably been formed by interactions between carbonatite melts and exsolved garnets in high-degree melt extraction residues. At the second stage of metasomatism, garnets with weakly sinusoidal REE patterns (“Lz 3”, “W”) were affected by a silicate melt possessing a REE composition similar to that of ADP alkaline mica-poor picrites. At the last stage, the garnets interacted with basaltic melts, which resulted in the decrease CaO-Cr2O3 trend of “Lz 2” garnet composition. Cr-poor garnets of megacryst paragenesis (“Meg”) could crystallize directly from the silicate melt which has a REE composition close to that of ADP alkaline mica-poor picrites. P-T estimates of the garnet xenocrysts indicate that the interval of ?60-110 km of the lithospheric mantle beneath the V. Grib pipe was predominantly affected by the silicate melts, whereas the lithospheric mantle deeper than 150 km was influenced by the carbonatite melts.
DS201701-0034
2016
Agashev, A.M.Surgutanova, E.A., Agashev, A.M., Demonterova, E.I., Golovin, A.V., Pokhilenko, N.P.Sr and Nd isotope composition of deformed peridotite xenoliths from Udachnaya kimberlite pipe.Doklady Earth Sciences, Vol. 471, 1, pp. 1104-1207.RussiaDeposit - Udachnaya

Abstract: New results of Rb-Sr and Sm-Nd isotope analyses have been obtained on samples of deformed peridotite xenoliths collected from the Udachnaya kimberlite pipe (Yakutia). The data obtained imply two main stages of metasomatic alteration of the lithospheric mantle base matter in the central part of the Siberian Craton. Elevated ratios of Sr isotopes may be considered as evidence of an ancient stage of metasomatic enrichment by a carbonatite melt. The acquired Nd isotope composition together with the geochemistry of the deformed peridotite xenoliths suggests that the second stage of metasomatic alteration took place shortly before formation of the kimberlite melt. The metasomatic agent of this stage had a silicate character and arrived from an asthenosphere source, common for the normal OIB type (PREMA) and the Group-I kimberlite.
DS201709-2000
2017
Agashev, A.M.Ilyina, O.V., Pokhilenko, L.N., Agashev, A.M.Characteristics of platinum group elements ( PGE) distribution in mantle xenoliths from kimberlite Udachnaya pipe ( Yakutia).Goldschmidt Conference, abstract 1p.Russia, Yakutiadeposit - Udachnaya

Abstract: We report PGE data in xenoliths of the deformed and granular peridotites. The deformed peridotites are the most deep-seated rocks and represent a narrow range of depth (180-220 km) while granular peridotites are located throughout the section of the lithospheric mantle. PGE distribution in the deformed peridotites [1] generally corresponds to that in our granular peridotites and xenoliths from Lesotho [2]. But in contrast with broad range of PGE concentrations in granular peridotites, the deformed peridotites show nearly flat pattern from Os to Pt, except of Pd (Fig.1). Granular peridotites show good positive correlation between PGE and Fe2O3. We suppose that they enriched in PGE by iron phase during its evolution. As for deformed peridotites we propose that they were depleted in Ir and Os followed by the increase of Ga and Cpx on the first stage of mantle metasomatism. On the last stage the enrichment of Pt, Pd and Re was probably a result of submicron sulphide phase’s presipitation in the interstices of mantle rocks.
DS201807-1477
2018
Agashev, A.M.Agashev, A.M., Pokhilenko, L.N., Pokhilenko, N.P., Shchukina, E.V.Geochemistry of eclogite xenoliths from the Udachnaya kimberlite pipe: section of ancient oceanic crust sampled.Lithos, DOI:10.1016 /j.lithos.2018 .05.027 available 52p.Russiadeposit - Udachnaya

Abstract: A suite of seventeen unique, large, and fresh eclogite xenoliths from the Udachnaya pipe have been studied for their whole-rock and mineral major- and trace-element compositions. Based on their major-element compositions, the Udachnaya eclogites can be subdivided in two groups: high magnesian (Mg# 68.8-81.9) and low magnesian (Mg# 56.8-59). The two eclogite groups are clearly different in the style of correlation between major elements. Positive correlations of FeO and CaO with MgO are observed in the low-magnesian group, whereas these correlations are negative in the high-magnesian group. In terms of trace element composition, the Udachnaya eclogites are enriched over Primitive Mantle, but comparable to mid-ocean-ridge basalt composition, except for significant enrichment in large-ion lithophile elements (LILE; Rb, Ba, K, Sr). Most of the samples show a positive Eu anomaly, irrespective of group. Reconstructed whole-rock composition from clinopyroxene and garnet modal abundances contains much less incompatible elements (LILE, light rare earth elements, high field strength elements) than measured composition. Approximately 60 to 100% of the middle rare earth elements, Zr, and Hf, and nearly 100% of the heavy rare earth elements, Co, V, and Sc of the whole-rock budget are concentrated in Gar and Cpx. Variations in major element compositions cover a full section of the modern and Archaean oceanic crust, from troctolite, through gabbroic rocks, to basalts. The low-Mg# eclogites could have formed from upper oceanic crust protoliths, being a mixture of basalts and gabbro, whereas the high-Mg# eclogites are originated from gabbro-troctolite section of the lower oceanic crust. Concordant variations of Eu anomaly with the Lu/Sr ratio and the V and Ni contents in the eclogite compositions are in agreement with the fractionation of plagioclase, clinopyroxene, and olivine in their low-pressure precursor rocks. Negative correlations of SiO2 and MgO, and a low Nd/YbNMORB ratio, in the low-Mg# eclogites are in agreement with partial melt loss, but the presence of accessory quartz limits the degree of melting to 13%. Major and trace element compositions suggest that the high-Mg# eclogites, and, consequently, the lower oceanic crust, could not have experienced significant melt loss, and subduction in the Archaean may have been essentially dry, compared to the present day.
DS201808-1722
2018
Agashev, A.M.Agashev, A.M., Nakai, S., Serov, I.V., Tolstov, A.V., Garanin, K.V., Kovalchuk, O.E.Geochemistry and origin of the Mirny field kimberlites, Siberia.Mineralogy and Petrology, doi.org/10.1007/s00710-018-06174 12p.Russia, Siberiadeposit - Mirny

Abstract: Here we present new data from a systematic Sr, Nd, O, C isotope and geochemical study of kimberlites of Devonian age Mirny field that are located in the southernmost part of the Siberian diamondiferous province. Major and trace element compositions of the Mirny field kimberlites show a significant compositional variability both between pipes and within one diatreme. They are enriched in incompatible trace elements with La/Yb ratios in the range of (65-00). Initial Nd isotope ratios calculated back to the time of the Mirny field kimberlite emplacement (t?=?360 ma) are depleted relative to the chondritic uniform reservoir (CHUR) model being 4 up to 6 ?Nd(t) units, suggesting an asthenospheric source for incompatible elements in kimberlites. Initial Sr isotope ratios are significantly variable, being in the range 0.70387-0.70845, indicating a complex source history and a strong influence of post-magmatic alteration. Four samples have almost identical initial Nd and Sr isotope compositions that are similar to the prevalent mantle (PREMA) reservoir. We propose that the source of the proto-kimberlite melt of the Mirny field kimberlites is the same as that for the majority of ocean island basalts (OIB). The source of the Mirny field kimberlites must possess three main features: It should be enriched with incompatible elements, be depleted in the major elements (Si, Al, Fe and Ti) and heavy rare earth elements (REE) and it should retain the asthenospheric Nd isotope composition. A two-stage model of kimberlite melt formation can fulfil those requirements. The intrusion of small bodies of this proto-kimberlite melt into lithospheric mantle forms a veined heterogeneously enriched source through fractional crystallization and metasomatism of adjacent peridotites. Re-melting of this source shortly after it was metasomatically enriched produced the kimberlite melt. The chemistry, mineralogy and diamond grade of each particular kimberlite are strongly dependent on the character of the heterogeneous source part from which they melted and ascended.
DS201808-1775
2017
Agashev, A.M.Paquette, J.L., Ionov, D.A., Agashev, A.M., Gannoun, A., Nikolenko, E.I.Age, provenance and Precambrian evolution of the Anabar shield from U Pb and Lu Hf isotope dat a on detrital zircons, and the history of the northern and central Siberian craton.Precambrian Research, Vol. 301, pp. 134-144.Russiacraton

Abstract: The Anabar shield in northern Siberia is one of the world’s least studied Precambrian areas, and provides a ‘window’ into the crustal basement of the central and northern Siberian craton. We report U-Pb and Hf isotope data for detrital zircons sampled in a profile across its major structural units. They define a U-Pb age range from 1.8 to 3.4 Ga with three main periods: 1.8-2.0 Ga, 2.4-2.8 Ga and 3.0-3.4 Ga. The oldest zircons yield super-chondritic ?Hf(t) implying that the parental magmas of their source rocks were juvenile, i.e. formed from depleted mantle (DM). Thus, the crustal basement of the Anabar shield, and probably the whole central and northern Siberian craton, started to form in the mid-Paleoarchean, and included no recycled crust. Zircons with 2.5-2.7 Ga ages define two ?Hf(t) intervals. One is super-chondritic (+2 to +7) implying juvenile sources, the other is sub-chondritic (?3 to ?12) indicative of recycled crust, probably formed at 3.2-3.4 Ga, in magma sources. Nearly all 1.8-2.0 Ga zircons have sub-chondritic ?Hf(t) (?2 to ?29) implying derivation from sources dominated by recycled crust formed at ?2.6 Ga and ?3.4 Ga and little or no juvenile addition. These events accompanied amalgamation of the entire craton by welding of Archean domains. The Bekelekh unit of the Daldyn series has the highest proportion of ?2.6 Ga zircons and may be the oldest ‘nucleus’ of the Anabar shield, whereas the Kilegur unit of the same series is essentially Proterozoic (1.95 Ga). The largest amount of 3.1-3.4 Ga zircons, as well as common 2.6-2.7 Ga zircons, occur in the Ambardakh unit of the Upper Anabar series. Our data suggest alternation of areas with dominant ages of 1.95 Ga and ?2.6 Ga, with the younger zircons coming from granites and granulites, and the older ones from gneisses. They show no evidence for significant ages differences for the Anabar and Olenek provinces. The final amalgamation of the entire Siberian craton by welding of Archean blocks, may have taken place at around 1954 ± 6 Ma.
DS201903-0501
2019
Agashev, A.M.Chepurov, A., Faryad, S.W., Agashev, A.M.Experimental crystallization of a subcalcic Cr-rich pyrope in the presence of REE bearing carbonatite.Chemical Geology, carbonatite

Abstract: This paper focuses on formation of subcalcic Cr-rich garnet (up to 14.25?wt% Cr2O3) in the model ultramafic system corresponding to natural harzburgite with the presence of REE-bearing fluid phase. The experiments were carried out using a “split-sphere” type multi-anvil high-pressure apparatus (BARS) at a pressure of 5?GPa and a temperature of 1300?°C. Natural serpentine, chromite, corundum and REE-carbonatite were used as starting components. Crystallization of garnet occurred in subsolidus conditions by the reaction of orthopyroxene and spinel in the presence of fluid phase. Composition of fluid was controlled by interaction of water released by decomposition of serpentine with carbonate. By using different amounts of carbonatite (0.5 and 1.5?wt%) as a source of calcium and REE, subcalcic Cr-rich garnets with up to 3.5?wt% CaO were crystallized, which are typical for inclusions of harzburgitic paragenesis in natural diamonds. The experiments demonstrated that the rare earth elements (REE) released from the initial carbonatite were transported by the fluid and were incorporated into the newly formed garnet. The distribution of REE in garnet revealed a vivid enrichment toward the heavy REE (HREE), showing the pattern with a very steep slope. These results confirmed high partitioning of HREE into garnet. The present study indicates that the mantle carbonatites, which contain very high proportions of light REE (LREE) to HREE, can play an important role as source material in formation of REE-rich fluids to crystallize garnets with typical REE patterns in mantle peridotites.
DS201909-2014
2019
Agashev, A.M.Agashev, A.M.Geochemistry of garnet megacrysts from the Mir kimberlite pipe ( Yakutia) and the nature of protokimberlite melts.Doklady Earth Sciences, Vol. 486, 2, pp. 675-678.Russiadeposit -Mir

Abstract: The chemical compositions of garnets from a megacryst association of the Mir kimberlite pipe have been studied. By petrogenic elements, the garnet megacrysts can be classified as high-Ti and low-Cr pyrope. The megacryst TiO2 contents of the Mir pipe correlate inversely with the MgO and Cr2O3 contents. Modeling of the composition of garnets through a fractional crystallization process showed that the most suitable composition of the melts parental for the garnets of the megacryst association is picrite. The composition of garnets crystallized from the kimberlite does not correspond to the composition of the natural garnets from the Mir pipe. The kimberlites contain less Ti, Zr, Y, and HREEs, but are more enriched with strongly incompatible elements (LREEs, Th, U, Nb, Ta, and Ba) than the model composition of the melt suitable for crystallization of the garnet megacrysts.
DS201909-2074
2019
Agashev, A.M.Pernet-Fisher, J.F., Barry, P.H., Day, J.M.D., Pearson, D.G., Woodland, S., Agashev, A.M., Pokhilenko, L.N., Pokhilenko, N.P.Heterogeneous kimberlite metasomatism revealed from a combined He-Os isotope study of Siberian megacrustalline dunite xenoliths.Geochimica et Cosmochimica Acta, in press available 45p. PdfRussia, Siberiadeposit - Udachnaya East
DS201909-2087
2019
Agashev, A.M.Shchukina, E.V., Agashev, A.M., Soloshenko, N.G., Streletskaya, M.V.Origin of the V. Grib pipe eclogites ( Arkhangelsk region, NW Russia): geochemistry, Sm-Nd and Rb-Sr isotopes and relation to regional Precambrian tectonics.Mineralogy and Petrology, in press available 20p. PdfRussia, Archangeldeposit - Grib

Abstract: In this paper, new main and trace elements and isotopic data are presented for 14 coarse-grained eclogite xenoliths from the V. Grib kimberlite pipe in the central part of the Arkhangelsk Diamondiferous Province. Based on reconstructed whole rock MgO content, this suite is divided into high-MgO and low-MgO varieties. Eclogitic groups have a similar range of variations in the trace element compositions of garnet, clinopyroxene and reconstructed whole rock. All eclogites show positive Eu anomalies in garnet and Sr anomalies in the whole rock. The negative correlation between the Mg#, Sr/Lu ratio and HREE in a whole rock points to upper and lower oceanic crustal rocks as a protolith for eclogites with high and low whole rock HREEs, respectively. Low-MgO eclogites with higher whole rock HREEs have the basaltic upper oceanic crustal protolith, whereas the protoliths of eclogites with lower whole rock HREEs could be of gabbroic composition from the lower oceanic crust. High-MgO eclogites could represent MgO-rich portions of oceanic crustal rocks: picritic/MgO basalt portions in the upper oceanic crust and troctolite portions in the lower oceanic crust. The Sr and Nd isotope compositions suggest a complex history of eclogites during their residence in the lithospheric mantle. Similarities in the Nd isotope compositions and two-point Sm-Nd isochron ages are evidence for re-equilibration of the Sm-Nd isotope system between the eclogite garnet and clinopyroxene via a pre-kimberlite thermal event at 396?±?24 Ma. The subset of clinopyroxenes from four eclogites has a Sr isotope composition that plots on the isochron at an age of 2.84 Ga, which reflects the time of the subduction event and emplacement into the lithosphere and corresponds to the time of the Belomorian Eclogite Province of Baltic Shield formation.
DS202005-0719
2020
Agashev, A.M.Agashev, A.M., Chervyakovskaya, M.V., Serov, I.V., Tolstov, A.V., Agasheva, E.V., Votyakov, S.L.Source rejuvenation vs. re-heating: constraints on Siberian kimberlite origin from U-Pb and Lu-Hf isotope compositions and geochemistry of mantle zircons. ( Silurian, Devonian, Triassic, Jurassic)Lithos, Vol. 364-365, 10p. PdfRussia, Siberiadeposit - Druzhba, Choumurdakh

Abstract: We have studied a suite of mantle zircons from several differently aged pipes of the Siberian kimberlite province via UPb and LuHf isotope analyses and trace element compositions. The UPb ages we obtained confirmed four main episodes (Silurian, Devonian, Triassic and Jurassic) of kimberlite activity on the Siberian craton. The Druzhba pipe had two populations of zircons dating from the Silurian and Devonian, respectively. The geochemical features of our suite of mantle zircons show low concentrations of U, Th and heavy rare earth elements (REEs), positive Ce anomalies, and weak or absent Eu anomalies, which is in accord with the mantle-derived nature of the zircon. Despite having broadly similar geochemistry, zircons from differently aged kimberlites had some clear differences arising from variations in the composition of the protokimberlite metasomatic melt and from peculiarities of fractional crystallization. The Th/U ratios were highest in the Silurian zircons and sharply decreased toward the Devonian. The Triassic zircons had elevated and highly variable Ce/Nb ratios with low and nearly constant Th/U ratios. Zircons from Siberian kimberlites with different UPb ages showed systematic variations in their initial Hf isotope compositions. The oldest Silurian kimberlite field, Chomurdakh, had two zircon populations: Silurian zircons, with ?Hft values in the range of +2.8 to +5.9 units, and Devonian zircons, with ?Hft values in the range of +1.6 to +2.0 units. Zircons from the Devonian field kimberlites were in the range of +5.6 to +9.6 ?Hft units. The Triassic kimberlitic zircons had the most juvenile Hf isotope composition, at +9.3 to +11.2 ?Hft units, while the Jurassic zircons had +6.9 ?Hft units. The combination of the UPb and LuHf isotope data suggests a periodic rejuvenation of the lithospheric mantle roots by low-volume melts from the asthenospheric mantle, resulting shortly after in kimberlite emplacements. Some Devonian and Jurassic kimberlites may have been melted by re-heating the Silurian and Triassic age sources, respectively, about 60 Myr after they were formed.
DS202108-1267
2021
Agashev, A.M.Agasheva, E.V., Kolesnichenko, M.V., Malygina, E.V., Agashev, A.M., Zedgenizov, D.A.Origin of water in mantle eclogites from the V. Grib kimberlite pipe, NW Russia.Lithosphere, Vol. 2021, 7866657, 18p. PdfRussia, Arkangelskdeposit - Grib

Abstract: The water content in the garnet and clinopyroxene in the mantle eclogites from the V. Grib kimberlite pipe (Arkhangelsk Diamondiferous Province, NW Russia) was analysed using Fourier transform infrared spectrometry. The results show that all clinopyroxene grains contained structural water at concentrations of 39 to 247?ppm, whereas two garnet samples contained detectable water at concentrations of 211 and 337?ppm. The low-MgO eclogites with oceanic gabbro precursors contained significantly higher water concentrations in the omphacites (70-247?ppm) and whole rock (35-224?ppm) compared to those with oceanic basalt protoliths (49-73?ppm and 20-36?ppm, respectively). The incorporation of water into the clinopyroxene may be associated with vacancies at the M2 site, Al in the tetrahedral position, and the elements that filled the M2 site (mostly Na and Ca). The highest water content in the omphacite was detected in a nonmetasomatised sample and was assumed to represent residual water that survived during subduction. Other eclogite samples showed signs of modal and/or cryptic metasomatism and contained less water in the omphacites compared to the nonmetasomatised sample. The water content was heterogeneous within the eclogite section of the sampled lithospheric mantle. The lack of distinct and uniform correlations between the indices of eclogite modification and their water content indicated that the saturation with water was disturbed during their residence within the lithospheric mantle.
DS202109-1486
2021
Agashev, A.M.Ragozin, A.I., Agashev, A.M., Zedgenizov, D.A., Denisenko, A.A.Evolution of the lithospheric mantle beneath the Nakyn kimberlite field: evidence from garnets in the peridotite xenoliths of the Nyurba and Botuoba pipes.Geochemistry International, Vol. 59, 8, pp. 743-756. pdfRussia, Siberiadeposit - Nyurba, Botuoba

Abstract: The paper presents data on garnets from serpentinized peridotite xenoliths in the Nyurba and Botuoba kimberlite pipes of the Nakyn kimberlite field. The major and trace-element compositions of the garnets were analyzed to determine their compositional specifics and genesis. Based on the REE content and chondrite-normalized distribution patterns, the garnets are divided into two types with sinusoidal ((Sm/Er)n > 1) and normal ((Sm/Er)n < 1) REE distribution patterns. In terms of the Y, Zr, Ti, and Eu relations, and the shape of REE distribution pattern, all the garnets correspond to garnets of metasomatized peridotites, except for one sample falling into the field of depleted garnets of harzburgite-dunite paragenesis. The geochemical characteristics of the garnets record two types of metasomatic agents: carbonatite/fluid for type 1 garnets and silicate/melt for type 2 garnets. The carbonatite metasomatic agent produced harzburgitic garnet and its further transformation into lherzolitic garnet. Silicate metasomatism, which led to the formation of the REE pattern of type 2 garnets, likely overprinted two different types of garnets and, respectively, gave two evolutionary trends. These are depleted residual garnets and type 1 garnets previously subjected to carbonatite metasomatism. The low Y and Th contents in combination with the low Ti/Eu ratios in garnets suggest a moderate reworking of lithospheric peridotites by silicate melts, which is consistent with the high diamond grade of the Nakyn kimberlite field.
DS202110-1642
2021
Agashev, A.M.Tychkov, N.S., Agashev, A.M., Pokhilenko, N.P.Lithospheric refertilization trends in xenoliths and xenocrysts from the Udachnaya kimberlite ( Siberian craton).Doklady Earth Sciences, Vol. 499, 2, pp. 634-638.Russiadeposit - Udachnaya

Abstract: Comprehensive studies of peridotitic xenoliths from the Udachnaya kimberlite (Yakutian diamond province, Siberian craton) confirm that garnet shows inverse correlation of its volumetric percentage with its Cr2O3 contents in refertilizated peridotites, but no such correlation is observed in depleted peridotites. The correlation relationship plots as an isosceles hyperbola, which is consistent with the existing knowledge of origin of refertilized peridotite. The bulk content of aluminum is proportional to the garnet percentage both in depleted and refertilized peridotites, but Al2O3 in the rock correlates with Cr2O3 in garnet only in the refertilized varieties, while the two parameters are independent in depleted mantle rocks. According to the modeling of refertilization-related composition changes in the Udachnaya peridotites, garnet percentages are directly proportional to the amount of clinopyroxene (Gnt = 0.879*Cpx + 0.022, R2 = 0.78) and inversely proportional to that of olivine (Gnt = 0.026/Ol3.141, R2 = 0.79). As the shares of Gnt and Cpx increase from minimum values, orthopyroxene first increases (to 0.16) and then decreases since 0.65 Ol, 0.09 Cpx, and 0.10 Gnt. This model can constrain the place of the parent rock in the refertilization series knowing Cr2O3 contents in separate garnet grains. The average refertilization degree of lithospheric mantle in the region estimated from the compositions of more than 800 garnet xenocrysts in the Udachnaya kimberlite is expressed in the rock modal composition as: Ol = 0.72, Opx = 0.15, Gnt = 0.07, and Cpx = 0.06 (median values).
DS201112-1062
2011
Agashev, N.Tychkov, N., Agashev, N., Poikilenko, N., Bazhan, I.Estimation of the refertilization grade of lithosphere roots by the chemical composition of garnets from Siberian kimberlites.Doklady Earth Sciences, Vol. 439, 2, pp. 1175-1178.Russia, SiberiaGarnet geochemistry
DS202106-0920
2021
Agasheva, E.Agasheva, E.Magmatic material in sandstone shows prospects for new diamond deposits within the northern east European platform.Minerals, Vol. 11, 339. doi.org/10.3390/min11040339 27p. PdfRussia, Arkhangelskdeposit - KL-01

Abstract: A detailed study of sandstones recovered from the upper part of the recently discovered KL-01 magmatic pipe in the southern part of the Arkhangelsk diamondiferous province (ADP), containing magmatic material and rare kimberlite indicator minerals, is presented in this paper. Results are compared to the composition of crater samples of the highly diamondiferous Vladimir Grib kimberlite pipe and several poorly to non-diamondiferous ADP pipes. To identify the type of magmatic material admixture, a model of binary mixing between country Vendian sandstones and typical ADP magmatic rocks based on correlations of La/Yb and Zr/Nb ratios and Ni contents is proposed. The modeling results show that the type of magmatic component in the KL-01 samples can be identified as kimberlite, with a maximum admixture of 20 vol.%. Kimberlite indicator mineral geochemistry did not exclude the interpretation that the composition, structure, thermal state and metasomatic enrichment of the lithospheric mantle sampled by the KL-01 pipe were suitable for the formation and preservation of diamonds. The lower boundary of the sampled lithospheric mantle could be in the depth range of 175-190 km, with a diamond window width of 55-70 km. Thus, the sandstones could represent the upper level of the crater of a new kimberlite pipe.
DS202005-0719
2020
Agasheva, E.V.Agashev, A.M., Chervyakovskaya, M.V., Serov, I.V., Tolstov, A.V., Agasheva, E.V., Votyakov, S.L.Source rejuvenation vs. re-heating: constraints on Siberian kimberlite origin from U-Pb and Lu-Hf isotope compositions and geochemistry of mantle zircons. ( Silurian, Devonian, Triassic, Jurassic)Lithos, Vol. 364-365, 10p. PdfRussia, Siberiadeposit - Druzhba, Choumurdakh

Abstract: We have studied a suite of mantle zircons from several differently aged pipes of the Siberian kimberlite province via UPb and LuHf isotope analyses and trace element compositions. The UPb ages we obtained confirmed four main episodes (Silurian, Devonian, Triassic and Jurassic) of kimberlite activity on the Siberian craton. The Druzhba pipe had two populations of zircons dating from the Silurian and Devonian, respectively. The geochemical features of our suite of mantle zircons show low concentrations of U, Th and heavy rare earth elements (REEs), positive Ce anomalies, and weak or absent Eu anomalies, which is in accord with the mantle-derived nature of the zircon. Despite having broadly similar geochemistry, zircons from differently aged kimberlites had some clear differences arising from variations in the composition of the protokimberlite metasomatic melt and from peculiarities of fractional crystallization. The Th/U ratios were highest in the Silurian zircons and sharply decreased toward the Devonian. The Triassic zircons had elevated and highly variable Ce/Nb ratios with low and nearly constant Th/U ratios. Zircons from Siberian kimberlites with different UPb ages showed systematic variations in their initial Hf isotope compositions. The oldest Silurian kimberlite field, Chomurdakh, had two zircon populations: Silurian zircons, with ?Hft values in the range of +2.8 to +5.9 units, and Devonian zircons, with ?Hft values in the range of +1.6 to +2.0 units. Zircons from the Devonian field kimberlites were in the range of +5.6 to +9.6 ?Hft units. The Triassic kimberlitic zircons had the most juvenile Hf isotope composition, at +9.3 to +11.2 ?Hft units, while the Jurassic zircons had +6.9 ?Hft units. The combination of the UPb and LuHf isotope data suggests a periodic rejuvenation of the lithospheric mantle roots by low-volume melts from the asthenospheric mantle, resulting shortly after in kimberlite emplacements. Some Devonian and Jurassic kimberlites may have been melted by re-heating the Silurian and Triassic age sources, respectively, about 60 Myr after they were formed.
DS202108-1267
2021
Agasheva, E.V.Agasheva, E.V., Kolesnichenko, M.V., Malygina, E.V., Agashev, A.M., Zedgenizov, D.A.Origin of water in mantle eclogites from the V. Grib kimberlite pipe, NW Russia.Lithosphere, Vol. 2021, 7866657, 18p. PdfRussia, Arkangelskdeposit - Grib

Abstract: The water content in the garnet and clinopyroxene in the mantle eclogites from the V. Grib kimberlite pipe (Arkhangelsk Diamondiferous Province, NW Russia) was analysed using Fourier transform infrared spectrometry. The results show that all clinopyroxene grains contained structural water at concentrations of 39 to 247?ppm, whereas two garnet samples contained detectable water at concentrations of 211 and 337?ppm. The low-MgO eclogites with oceanic gabbro precursors contained significantly higher water concentrations in the omphacites (70-247?ppm) and whole rock (35-224?ppm) compared to those with oceanic basalt protoliths (49-73?ppm and 20-36?ppm, respectively). The incorporation of water into the clinopyroxene may be associated with vacancies at the M2 site, Al in the tetrahedral position, and the elements that filled the M2 site (mostly Na and Ca). The highest water content in the omphacite was detected in a nonmetasomatised sample and was assumed to represent residual water that survived during subduction. Other eclogite samples showed signs of modal and/or cryptic metasomatism and contained less water in the omphacites compared to the nonmetasomatised sample. The water content was heterogeneous within the eclogite section of the sampled lithospheric mantle. The lack of distinct and uniform correlations between the indices of eclogite modification and their water content indicated that the saturation with water was disturbed during their residence within the lithospheric mantle.
DS1996-1301
1996
Agata, T.Shibata, K., Suwa, K., Agata, T.Excess Argon in biotites from Broderick Falls (Webuye) area, western Kenya: implications for tectonothermal..Journal of African Earth Sciences, Vol. 23, No. 3, Oct. 1, pp. 433-442KenyaArchean, Mozambique belt
DS2001-0009
2001
Agbossoumonde, Y.Agbossoumonde, Y., Menot, R.P., Guillot, S.Metamorphic evolution of Neoproterozoic eclogites from south To go (West Africa)Journal of African Earth Sciences, Vol.33,2,Aug.pp.227-44.Togo, West AfricaEclogites, Metamorphism
DS1989-1572
1989
Agee, C.Walker, D., Agee, C.Partioning "equilibrium",temperature gradients, and constraints on earthdifferentiationEarth and Planetary Science Letters, Vol. 96, pp. 49-60GlobalMantle petrogenesis -experimental petrology, Perovskites
DS1989-0009
1989
Agee, C.B.Agee, C.B., Walker, D.Comments on constraints on element partition coefficients between MgSiO3perovskite and liquid determined by direct measurementsEarth and Planetary Science Letters, Vol. 94, pp. 160-163GlobalMantle, Petrogenesis
DS1990-0104
1990
Agee, C.B.Agee, C.B.A new look at differentiation of the earth from melting experiments on the Allende meteoriteNature, Vol. 346, No. 6287 August 30, pp. 834-837GlobalMeteorite
DS1993-0011
1993
Agee, C.B.Agee, C.B.Petrology of the mantle transition zoneAnnual Review of Earth and Planetary Sciences, Vol. 21, pp. 19-42MantlePetrology
DS1993-0012
1993
Agee, C.B.Agee, C.B., Walker, D.Olivine flotation in mantle meltEarth and Planetary Science Letters, Vol. 114, No. 2/3, January pp. 315-324MantleGeochemistry, Olivine
DS1996-0840
1996
Agee, C.B.Li, J., Agee, C.B.Geochemistry of mantle core differentiation at high pressuresNature, Vol. 381, No. 6584, June 20, pp. 686-688.MantleGeochemistry
DS1998-0012
1998
Agee, C.B.Agee, C.B.Phase deformations and seismic structure in the Upper Mantle and transitionzone.Reviews in Mineralogy, Vol. 37, pp. 165-204.MantleGeophysics - seismics, Geodynamics - boundary
DS2001-0682
2001
Agee, C.B.Li, J., Agee, C.B.Element partitioning constraints on the light element composition of the Earth's core.Geophysical Research Letters, Vol. 28, No. 1, Jan. pp.81-4.MantleGeochemistry - core
DS200612-0358
2006
Agee, C.B.Dwarzski, R.E., Draper, D.A., Shearer, C.K., Agee, C.B.Experimental insights on crystal chemistry of high Ti garnets from garnet melt partitioning of rare earth and high field strength elements.American Mineralogist, Vol. 91, 9, pp. 1536-1546.TechnologyPetrology - crystal chemistry
DS200812-0005
2008
Agee, C.B.Agee, C.B.Compressibility of water in magma and the prediction of density crossovers in mantle differentiation.Philosophical Transactions Royal Society of London Series A Mathematical Physical and Engineering Sciences, Vol. 366, no. 1883, pp. 4239-4252.MantleMagmatism
DS201212-0726
2012
Agee, C.B.Thoma, C.W., Liu, Q., Agee, C.B., Asimov, P.D., Lange, R.A.Multi-technique equation for Fe2SiO4 melt and the density of Fe bearing silicate melts from 0 to 161 Gpa.Journal of Geophysical Research, Vol. 117, 18p. B10206TechnologyMantle mineralogy
DS1980-0002
1980
Agee, J.Agee, J., Garrison, J.R.JR., Taylor, L.A.Kimberlites: a Window Into the Mantle Beneath the Southeastern Appalachians #1Geological Society of America (GSA), Vol. 12, No. 4, P. 169. (abstract.).Appalachia, VirginiaGeology
DS1980-0003
1980
Agee, J.J.Agee, J.J., Garrison, J.R.JR., Taylor, L.A.Kimberlites: a Window Into the Mantle Beneath the Southeastern Appalachians #2Eos, Vol. 61, No. 17, P. 412, (abstract.).Appalachia, KentuckyGeology
DS1982-0001
1982
Agee, J.J.Agee, J.J., Garrison, J.R.JR., Taylor, L.A.Petrogenesis of Oxide Minerals in Kimberlite, Elliott County, Kentucky.American Mineralogist., Vol. 67, No. 1-2, PP. 28-42.GlobalIlmenite, Petrography, Microprobe
DS1988-0480
1988
Ageeva, L.I.Mogarovskii, V.V., Davydova, Z.M., Ageeva, L.I.Tungsten in alkaline basaltic rocks of southern Tien-Shan andPamirs.(Russian)Doklady Academy of Sciences Nauk Tadzh. SSSR, (Russian), Vol. 31, No. 8, pp. 542-544RussiaAlkaline rocks
DS1987-0272
1987
Agena, W.F.Hamilton, R.M., Agena, W.F., McKeown, F.A.Deep structure of the new Madrid Seismic zone interpreted from seismic reflection profilesEos, Vol. 68, No.44, November 3, p. 1355. abstract onlyArkansas, MissouriGeophysics
DS1989-0010
1989
Agena, W.F.Agena, W.F., Lee, M.W., Grow, J.A.Reprocessing of the COCORP dat a recorded across the Wichita Mountain Uplift and the Anadarko Basin in southern OklahomaUnited States Geological Survey (USGS) Open File, No. 89-0357, 20p. $ 3.50GlobalGeophysics, Tectonics -COCORP
DS1990-1043
1990
Agena, W.F.Milkereit, B., Green, A.G., Lee, M.W., Agena, W.F., Spencer, C.Pre- and post stack migration of Glimpce reflection dataTectonophysics, Vol. 174, No. 1/2, March 1, pp. 1-14Ontario, MichiganGeophysics -Seismics, Glimpce
DS1990-1175
1990
Agena, W.F.Perry, W.J., Agena, W.F.Structural interpretations of the Ouachita frontal zone near HartshorneOklahoma, based on reprocessed seismic reflection dataGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A231GlobalTectonics, Geophysics -seismics
DS1994-1764
1994
Agenbacht, A.L.D.Thomas, R.J., Agenbacht, A.L.D., Cornell, D.H., Moore, J.M.The Kibaran of southern Africa: tectonic evolution and metallogenyOre Geology Reviews, Vol. 9, pp. 131-160South Africa, Ontario, NamaqualandSEDEX, metallogeny, Copper, nickel, VMS
DS1993-0013
1993
Ager, D.Ager, D.The new catastrophism... rare event in geological historyCambridge Press, 278p. $ 35.00GlobalBook -ad, CatastrophisM.
DS1994-0027
1994
Ager, D.Ager, D.The new catastrophism... rare event .Cambridge University of press, 231p. $ 25.00GlobalCatastrophisM., Book -ad
DS1993-1151
1993
Aggarwal, H.Oberbeck, V.R., Marshall, J.R., Aggarwal, H.Impacts, tillites and the breakup of GondwanalandJournal of Geology, Vol. 101, No. 1, January, pp. 1-19Craters, Rifting
DS1993-1152
1993
Aggarwal, H.Oberbeck, V.R., Marshall, J.R., Aggarwal, H.Impacts, tillites and the breakup of GondwanalandJournal of Geology, Vol. 101, No. 1, January pp. 1-19.Tectonics, Rifting
DS2002-1371
2002
Aggrawal, S.K.Roy, A., Sarkar, A., Jeyakumar, S., Aggrawal, S.K., Ebihara, M.Sm Nd age and mantle source characteristics of the Dhanjori volcanic rocks, eastern India.Geochemical Journal, Vol. 36, 5, pp. 503-18.IndiaGeochronology, magmatism
DS200512-0915
2004
Aggrawal, S.K.Roy, A., Sarkar, A., Jeyakumar, S., Aggrawal, S.K., Ebihara, M., Satoh, H.Late Archean mantle metasomatism below eastern Indian Craton: evidence from trace elements, REE geochemistry and Sr Nd O isotope systematics of ultramafic dykes.Proceedings National Academy of Sciences India , Vol. 113, 4, pp. 649-666. Ingenta 1045680437IndiaMetasomatism, geochemistry
DS200512-0916
2004
Aggrawal, S.K.Roy, A., Sarkar, A., Jeyakumar, S., Aggrawal, S.K., Ebihara, M., Satoh, H.Late Archean mantle metasomatism below eastern Indian craton: evidence from trace elements, REE geochemistry and Sr Nd O isotope systematics of ultramafic dykes.Proceedings National Academy of Sciences India , Vol. 113, 4, pp. 649-665.India, AsiaPeridotite, harzburgite, geochronology
DS1990-1073
1990
Aggrey, K.E.Muenow, D.W., Garcia, M.O., Aggrey, K.E., Bednarz, U., SchminckeVolatiles in submarine glasses as a discriminant of tectonic origin:application to the Troodos ophioliteNature, Vol. 343, No. 6254, January 11, pp. 159-161CyprusOphiolite, Tectonic origin
DS201902-0314
2019
Aghajani, H.Roshanravan, B., Aghajani, H., Yousefi, M., Kreuzer, O.An improved prediction-area plot for prospectivity analysis of mineral deposits ( not specific to diamonds).Natural Resources Research, doi.org/10.1007/s11053-018-9439-7 17p.Iranchromite

Abstract: In this paper an improved prediction-area plot has been developed. This type of plot includes performance measures similar to other existing methods (receiver operating characteristics, success-rate curves and ordinary prediction-area plots) and, therefore, offers a reliable method for evaluating the performance of spatial evidence maps and prospectivity models. To demonstrate the reliability of the improved prediction-area plot proposed, we investigated the benefits of augmented targeting criteria through remotely sensed exploration features, compared to only geological map-derived criteria, for mineral prospectivity analysis using as an example the podiform chromite deposits of the Sabzevar Ophiolite Belt, Iran. The application of the newly developed improved prediction-area plot to the prospectivity models generated in this study indicated that the augmented targeting criteria by using remote sensing data perform better than non-updated geological map-derived criteria, and that model effectiveness can be improved by using an integrated approach that entails geologic remote sensing.
DS1980-0004
1980
AgidAgidProspects for Production Cooperation Between India and GhanaA.g.i.d. News, No. 24, JULY, PP. 30-31.India, Ghana, West AfricaDiamond Production
DS200912-0107
2009
Agnard, F.Chardon, D., Capais, D., Agnard, F.Flow of ultra hot orogens: a review from the Precambrian, clues for the Phanerozoic.Tectonophysics, Vol. 477, pp. 105-118.MantleUHP, orogens
DS1996-0008
1996
Agnerian, H.Agnerian, H.Survey of mineral property transactions July 1994- to June 1996Preprint from author, 11pGlobalRange of the values of mineral property transactions, Economics
DS201112-0007
2011
Agnew, J.Agnew, J., Daniels, A.Safe by accident. BooksafeByaccident.com, $ 21.95 USGlobalBook - on safety for mining industry
DS1998-0997
1998
Agnon, A.Meriaux, C., Agnon, A., Lister, J.R.The thermal signature of subducted lithospheric slabs at the core mantleboundary.Earth and Planetary Science Letters, Vol. 160, No. 3-4, Aug. 1, pp. 551-562.MantleSubduction, Boundary
DS1999-0472
1999
Agnon, A.Meriaux, C., Lister, J.R., Agnon, A.Dike propagation with distributed damage of the host rockEarth and Planetary Science Letters, Vol. 165, No. 2, Jan. 30, pp. 177-86.GlobalDike, Tectonics
DS1992-0860
1992
Agoshkov, V.M.Khodyrev, O.Yu., Agoshkov, V.M., Slutskiy, A.B.The system peridotite-aequeous fluid at upper mantle parametersDoklady Academy of Science USSR, Earth Science Section, Vol. 312, No. 1-3, June pp. 255-258MantleModel, Peridotite
DS201902-0289
2018
Agostinetti, N.P.Lamarque, G., Agostinetti, N.P., Julia, J., Evain, M.Joint interpretation of SKS-splitting measurements and receiver function data for detecting seismic anisotropy in the upper mantle: feasibility and limitations.AGU, 1p. abstract Mantlegeophysics -seismic

Abstract: Measuring seismic anisotropy within the Earth is essential as it constitutes a proxy for inferring upper mantle deformation related to mantle flow, that develops preferred orientations of the minerals in response to tectonic strain. The most-used method to detect anisotropy beneath a seismic station is the measurement of teleseismic SKS wave splitting on two horizontal recordings, i.e. measuring the delay time (?t) between two fast- and slow- polarized shear-waves and the orientation of polarization (?). This technique allows a integrative measurement (SKS data, hereinafter) that estimates the average ? and ?t along the entire SKS ray-path. Despite its importance for large-scale anisotropy within the upper mantle, the analysis of SKS data suffers from several limitations : (1) SKS data become difficult to interpret in regions where several anisotropic layers occur; (2) SKS waves fail to provide robust information about anisotropy related to thin layers; and (3) SKS data can investigate rock volumes with an horizontal symmetry axis only. During the last decade a new method, called harmonic decomposition of teleseismic Receiver Functions (RFs) has been developed in order to detect more complex anisotropic layering. This methodology is based on the extraction of back-azimuth harmonics of the RF dataset. Briefly, it constitutes a tool to appreciate the value of ? and ?t at every depth-level affording a detailed study of the rock anisotropy with both plunging and horizontal symmetry axis. RFs studies are however commonly limited to the first 10-15s of the signal and do not sample the deepest anisotropy. In this work we investigate in details both SKS data and RFs harmonic decomposition for a pool of stations deployed in northeastern Brasil, in order to understand how results from the analysis of these two observables can be jointly interpreted. We focus our study on the permanent station RCBR and on temporary seismic stations deployed in the area. We show that comparison and/or joint interpretation is not straightforward as both results can vary according to the amount of data available and their distribution in back-azimuth, and filtering. However, tacking into account those issues, the integration of these two observables represent a great step-forward for robust detection of upper mantle anisotropy.
DS200512-1095
2005
Agostini, S.Tonarini, S., Agostini, S., Innocent, F., Manetti, P.d11B as tracer of slab dehydration and mantle evolution in western Anatolia Cenozoic magmatism.Terra Nova, Vol. 17, 3, pp. 259-264.MantleMagmatism - not specific to diamonds
DS201612-2318
2016
Agostini, S.Lustrino, M., Agostini, S., Chalal, Y., Fedele, L., Stagno, V., Colombi, F., Bouguerra, A.Exotic lamproites or normal ultrapotassic rocks? The Late Miocene volcanic rocks from Kef Hahouner, NE Algeria, in the frame of the circum-Mediterranean lamproites.Journal of Volcanology and Geothermal Research, in press available 15p.Africa, AlgeriaLamproite

Abstract: The late Miocene (11-9 Ma) volcanic rocks of Kef Hahouner, ~ 40 km NE of Constantine (NE Algeria), are commonly classified as lamproites in literature. However, these rocks are characterized by an anhydrous paragenesis with plagioclase and Mg-rich olivine phenocrysts, set in a groundmass made up of feldspars, pyroxenes and opaque minerals. Thus, we classify the Kef Hahouner rocks as ultrapotassic shoshonites and latites, having K2O > 3 wt.%, K2O/Na2O > 2.5, MgO > 3-4 wt.%, SiO2 < 55-57 wt.% and SiO2/K2O < 15. All the investigated samples show primitive mantle-normalized multi-element patterns typical of orogenic (arc-type) magmas, i.e. enriched in LILE (e.g. Cs, Rb and Ba) and LREE (e.g. La/Yb = 37-59) with respect to the HFSE, peaks at Pb and troughs at Nb and Ta. Initial isotopic ratios are in the range of 87Sr/86Sr = 0.70874-0.70961, 143Nd/144Nd = 0.51222-0.51223, 206Pb/204Pb = 18.54-18.60, 207Pb/204Pb = 15.62-15.70 and 208Pb/204Pb = 38.88-39.16. The Kef Hahouner volcanic rocks show multi-element patterns similar to the other circum-Mediterranean lamproites and extreme Sr, Nd and Pb isotopic compositions. Nevertheless, the abundant plagioclase, the presence of Al-rich augite coupled with high Al2O3 whole rock compositions (9.6-21.4 wt.%), and the absence of phlogopite are all at inconsistent with the definition of lamproite. We reviewed the rocks classified as lamproites worldwide, and found that many of these rocks, as for the Kef Hahouner samples, should be actually defined as "normal" potassic to ultrapotassic volcanic rocks. Even the grouping of lamproites into "orogenic" and "anorogenic" types appears questionable.
DS201902-0293
2019
Agostini, S.Lustrino, M., Fedele, L., Agostini, S., Prelevic, D., Salari, G.Leucitites within and around the Mediterranean area. Lithos, Vol. 324-325, pp. 216-233.Europeleucitites

Abstract: Leucite-bearing volcanic rocks are commonly found within and around the Mediterranean area. A specific type of this rock group are leucitites. They are found both in a hinterland position of active and fossil subduction systems as well as in foreland tectonic settings, but none have been found in the Maghreb (N Africa) and Mashreq (Middle East) areas. Here a review of the main leucitite occurrences in the circum-Mediterranean area is presented, with new whole-rock, mineral chemical and Sr-Nd-Pb isotopic ratios on key districts, with the aim of clarifying the classification and genesis of this rock type. Many of the rocks classified in literature as leucitites do not conform to the IUGS definition of leucitite (i.e., rocks with >10?vol% modal leucite and with foids/(foids + feldspars) ratio?>?0.9, with leucite being the most abundant foid). Among circum-Mediterranean rocks classified as leucitites in the literature, we distinguish two types: clinopyroxene-olivine-phyric (COP) and leucite- phyric (LP) types. Only the second group can be truly classified as leucitite, being characterized by the absence or the very rare presence of feldspars, as well as by ultrapotassic composition. The COP group can be distinguished from the LP group on the basis of lower SiO2, Na2O?+?K2O, K2O/Na2O, Al2O3, Rb and Ba, and higher MgO, TiO2, Nb, Cr and Ni. The LP group shows multi-elemental patterns resembling magmas emplaced in subduction-related settings, while COP rocks are much more variable, showing HIMU-OIB-like to subduction-related-like incompatible element patterns. COP rocks are also characterized generally by more homogeneous isotopic compositions clustering towards low Sr and high Nd isotopic ratios, while LP leucitites plot all in the enriched Sr-Nd isotopic quadrant. LP rocks usually have lower 206Pb/204Pb and higher 207Pb/204Pb. This study shows that the geochemical signal of mantle melts does not always reflect the tectonic setting of magma emplacement, suggesting paying extreme attention in proposing geodynamic reconstructions on the basis of chemical data only.
DS202009-1615
2020
Agostini, S.Cannao, E., Scambelluri, M., Bebout, G.E., Agostini, S., Pettke, T., Godard, M., Crispini, L.Ophicarbonate evolution from seafloor to subduction and implications for deep-Earth C cycling.Chemical Geology, Vol. 546, 119626 29p. PdfMantlecarbon, subduction

Abstract: The chemical and physical processes operating during subduction-zone metamorphism can profoundly influence the cycling of elements on Earth. Deep-Earth carbon (C) cycling and mobility in subduction zones has been of particular recent interest to the scientific community. Here, we present textural and geochemical data (CO, Sr isotopes and bulk and in-situ trace element concentrations) for a suite of ophicarbonate rocks (carbonate-bearing serpentinites) metamorphosed over a range of peak pressure-temperature (P-T) conditions together representing a prograde subduction zone P-T path. These rocks, in order of increasing peak P-T conditions, are the Internal Liguride ophicarbonates (from the Bracco unit, N. Apennines), pumpellyite- and blueschist-facies ophicarbonates from the Sestri-Voltaggio zone (W. Ligurian Alps) and the Queyras (W. Alps), respectively, and eclogite-facies ophicarbonates from the Voltri Massif. The Bracco oceanic ophicarbonates retain breccia-like textures associated with their seafloor hydrothermal and sedimentary origins. Their trace element concentrations and ?18OVSMOW (+15.6 to +18.2‰), ?13CVPDB (+1.1 to +2.5‰) and their 87Sr/86Sr (0.7058 to 0.7068), appear to reflect equilibration during Jurassic seawater-rock interactions. Intense shear deformation characterizes the more deeply subducted ophicarbonates, in which prominent calcite recrystallization and carbonation of serpentinite clasts occurred. The isotopic compositions of the pumpellyite-facies ophicarbonates overlap those of their oceanic equivalents whereas the most deformed blueschist-facies sample shows enrichments in radiogenic Sr (87Sr/86Sr?=?0.7075) and depletion in 13C (with ?13C as low as ?2.0‰). These differing textural and geochemical features for the two suites reflect interaction with fluids in closed and open systems, respectively. The higher-P-metamorphosed ophicarbonates show strong shear textures, with coexisting antigorite and dolomite, carbonate veins crosscutting prograde antigorite foliation and, in some cases, relics of magnesite-nodules enclosed in the foliation. These rocks are characterized by lower ?18O (+10.3 to 13.0‰), enrichment in radiogenic Sr (87Sr/86Sr up to 0.7096) and enrichment in incompatible and fluid-mobile element (FME; e.g., As, Sb, Pb). These data seemingly reflect interaction with externally-derived metamorphic fluids and the infiltrating fluids likely were derived from dehydrating serpentinites with hybrid serpentinite-sediment compositions. The interaction between these two lithologies could have occurred prior to or after dehydration of the serpentinites elsewhere. We suggest that decarbonation and dissolution/precipitation processes operating in ancient subduction zones, and resulting in the mobilization of C, are best traced by a combination of detailed field and petrographic observations, C, O and Sr isotope systematics (i.e., 3D isotopes), and FME inventories. Demonstration of such processes is key to advancing our understanding of the influence of subduction zone metamorphism on the mobilization of C in subducting reservoirs and the efficiency of delivery of this C to depths beneath volcanic arcs and into the deeper mantle.
DS202111-1773
2021
Agostini, S.Lustrino, M., Salari, G., Rahimzadeh, B., Fede;e, L. Masoudi, F., Agostini, S.Quaternary melanephelinites and melilitites from Nowbaran ( NW Urumieh-Dokhtar magmatic arc, Iran): origin of ultrabasic-ultracalcic melts in a post-collional setting.Journal of Petrology, Vol. 62, 9, pp. 1-31. pdfAsia, Iranmelilitite

Abstract: The small Quaternary volcanic district of Nowbaran (NW Iran) belongs to the Urumieh-Dokhtar Magmatic Arc, a ?1800-km long NW-SE striking Cenozoic belt characterized by the irregular but abundant presence of subduction-related igneous products. Nowbaran rocks are characterized by absence of feldspars coupled with abundance of clinopyroxene and olivine plus nepheline, melilite and other rarer phases. All the rocks show extremely low SiO2 (35.4-41.4?wt%), very high CaO (13.1-18.3?wt%) and low Al2O3 (8.6-11.6?wt%), leading to ultracalcic compositions (i.e. CaO/Al2O3?>?1). Other less peculiar, but still noteworthy, characteristics are the high MgO (8.7-13.3?wt%) and Mg# (0.70-0.75), coupled with a variable alkali content with sodic affinity (Na2O?=?1.8-5.4?wt%; K2O?=?0.2-2.3?wt%) and variably high LOI (1.9-10.4?wt%; average 4.4?wt%). Measured isotopic ratios (87Sr/86Sr?=?0.7052-0.7056; 143Nd/144Nd?=?0.51263-0.51266; 206Pb/204Pb?=?18.54-18.66; 207Pb/204Pb?=?15.66-15.68; 208Pb/204Pb?=?38.66-38.79) show small variations and plot within the literature field for the Cenozoic volcanic rocks of western Iran but tend to be displaced towards slightly higher 207Pb/204Pb. Primitive mantle-normalized multielemental patterns are intermediate between typical subduction-related melts and nephelinitic/melilititic melts emplaced in intraplate tectonic settings. The enrichment in Th, coupled with high Ba/Nb and La/Nb, troughs at Ti in primitive mantle-normalized patterns, radiogenic 87Sr/86Sr and positive ?7/4 anomalies (from +15.2 to +17.0) are consistent with the presence of (old) recycled crustal lithologies in the sources. The origin of Nowbaran magmas cannot be related to partial melting of C-H-free peridotitic mantle, nor to digestion of limestones and marls by ‘normal’ basaltic melts. Rather, we favour an origin from carbonated lithologies. Carbonated eclogite-derived melts or supercritical fluids, derived from a subducted slab, reacting with peridotite matrix, could have produced peritectic orthopyroxene- and garnet-rich metasomes at the expenses of mantle olivine and clinopyroxene. The residual melt compositions could evolve towards SiO2-undersaturated, CaO- and MgO-rich and Al2O3-poor alkaline melts. During their percolation upwards, these melts can partially freeze reacting chromatographically with portions of the upper mantle wedge, but can also mix with melts from shallower carbonated peridotite. The T-P equilibration estimates for Nowbaran magmas based on recent models on ultrabasic melt compositions are compatible with provenance from the lithosphere-asthenosphere boundary at average temperature (?1200°C?±?50°C). Mixing of melts derived from subduction-modified mantle sources with liquids devoid of any subduction imprint, passively upwelling from slab break-off tears could generate magmas with compositions recorded in Nowbaran.
DS200712-0004
2007
Agranier, A.Agranier, A., Lee, C-T.A.Quantifying trace element disequilibration temperatures in mantle xenoliths and abyssal peridotites.Earth and Planetary Science Letters, Vol. 257, 1-2, May 15, pp. 290-298.MantleGeochemistry
DS202104-0585
2021
Agranier, A.Kubik, E., Siebert, J., Blanchard, I., Agranier, A., Mahan, B., Moynier, F.Earth's volatile accretion as told by Cd, Bi, Sb and Ti core-mantle distribution.Geochimica et Cosmochimica Acta, in press available, 35p. PdfMantlegeodynamics
DS1985-0484
1985
Agrawal, P.K.Negri, J.G., Agrawal, P.K., Thakur, N.K.Vertical Component Magsat Anomalies and Indian Tectonic Boundaries.Indian Academy of Science Proceedings, Vol. 94, No. 1, MARCH PP. 35-42.IndiaGeotectonics
DS2001-0885
2001
Agrawal, P.K.Pandey, O.P., Agrawal, P.K.Nature of lithospheric deformation beneath the western continental margin of India.Journal of Geological Society India, Vol. 57, No. 6, pp. 497-506.IndiaTectonics
DS2002-1210
2002
Agrawal, P.K.Pandrey, O.P., Agrawal, P.K., Chetty, T.R.K.Unusual lithospheric structure beneath the Hyderabad granitic region, eastern Dharwar craton, south India.Physics of the Earth and Planetary Interiors, Vol. 130, 1-2, pp.59-69.India, southHeat flow, Cratonic mantle lithosphere
DS200412-0005
2004
Agrawal, P.K.Agrawal, P.K., Pandey, O.P.Unusual lithospheric structure and evolutionary pattern of the cratonic segments of the South Indian Shield.Earth Planets and Space, Vol. 56, 2, pp. 139-150. Ingenta 1043471076IndiaTectonics, eastern Dharwar Craton, geothermometry
DS200412-0006
2004
Agrawal, S.Agrawal, S., Guevara, M., Verma, S.P.Discriminate analysis applied to establish major element field boundaries for tectonic varieties of basic rocks.International Geology Review, Vol. 46, 7, pp. 575-594.TechnologyGeochemistry - not specific to diamonds
DS200612-0955
2005
Agredo, J.Munoz, M., Agredo, J., De Ignacio, C., Fernandez-Suarez, J., Jeffries, T.E.New dat a ( U Pb K Ar) on the geochronology of the alkaline carbonatitic association of Fuerteventura, Canary Islands, Spain.Lithos, Vol. 85, 1-4, Nov-Dec. pp. 140-153.Europe, SpainCarbonatite, Geochronology
DS202008-1422
2020
Agresti, D.G.McKensie, L., Kilgore, A.H., Peslier, A.D., Brandon, L.A., Schaffer, R.V., Graff, T.G., Agresti, D.G., O'Reilly, S.Y., Griffin, W.L., Pearson, D.G., Hangi, K., Shaulis, B.J.Metasomatic control of hydrogen contents in the layered cratonic mantle lithosphere sampled by Lac de Gras xenoliths in the central Slave craton, Canada.Geochimica et Cosmochimica Acta, in press available, doi.org/101016 /j.gca.2020.07.013 45p. PdfCanada, Northwest Territoriesdeposit - Lac de Gras

Abstract: Whether hydrogen incorporated in nominally anhydrous mantle minerals plays a role in the strength and longevity of the thick cratonic lithosphere is a matter of debate. In particular, the percolation of hydrogen-bearing melts and fluids could potentially add hydrogen to the mantle lithosphere, weaken its olivines (the dominant mineral in mantle peridotite), and cause delamination of the lithosphere's base. The influence of metasomatism on hydrogen contents of cratonic mantle minerals can be tested in mantle xenoliths from the Slave Craton (Canada) because they show extensive evidence for metasomatism of a layered cratonic mantle. Minerals from mantle xenoliths from the Diavik mine in the Lac de Gras kimberlite area located at the center of the Archean Slave craton were analyzed by FTIR for hydrogen contents. The 18 peridotites, two pyroxenites, one websterite and one wehrlite span an equilibration pressure range from 3.1 to 6.6 GPa and include samples from the shallow (? 145 km), oxidized ultra-depleted layer; the deeper (?145-180 km), reduced less depleted layer; and an ultra-deep (? 180 km) layer near the base of the lithosphere. Olivine, orthopyroxene, clinopyroxene and garnet from peridotites contain 30 - 145, 110 - 225, 105 - 285, 2 - 105 ppm H2O, respectively. Within each deep and ultra-deep layer, correlations of hydrogen contents in minerals and tracers of metasomatism (for example light over heavy rare-earth-element ratio (LREE/HREE), high-field-strength-element (HFSE) content with equilibration pressure) can be explained by a chromatographic process occurring during the percolation of kimberlite-like melts through garnet peridotite. The hydrogen content of peridotite minerals is controlled by the compositions of the evolving melt and of the minerals and by mineral/melt partition coefficients. At the beginning of the process, clinopyroxene scavenges most of the hydrogen and garnet most of the HFSE. As the melt evolves and becomes enriched in hydrogen and LREE, olivine and garnet start to incorporate hydrogen and pyroxenes become enriched in LREE. The hydrogen content of peridotite increases with decreasing depth, overall (e.g., from 75 to 138 ppm H2O in the deep peridotites). Effective viscosity calculated using olivine hydrogen content for the deepest xenoliths near the lithosphere-asthenosphere boundary overlaps with estimates of asthenospheric viscosities. These xenoliths cannot be representative of the overall cratonic root because the lack of viscosity contrast would have caused basal erosion of lithosphere. Instead, metasomatism must be confined in narrow zones channeling kimberlite melts through the lithosphere and from where xenoliths are preferentially sampled. Such localized metasomatism by hydrogen-bearing melts therefore does not necessarily result in delamination of the cratonic root.
DS202011-2047
2020
Agresti, D.G.Kilgore, M.L., Peslier, A.H., Brandon, A.D., Schaffer, L.A., Morris, R.V., Graff, T.G., Agresti, D.G., O'Reilly, S.Y., Griffin, W.L., Pearson, D.G., Barry, K.G., Shaulis, J.Metasomatic control of hydrogen contents in the layered cratonic mantle lithosphere sampled by Lac de Gras xenoliths in the central Slave Craton, Canada.Geochimica et Cosmochimica Acta, Vol. 286, pp. 29-83. pdfCanada, Northwest Territoriesxenoliths

Abstract: Whether hydrogen incorporated in nominally anhydrous mantle minerals plays a role in the strength and longevity of the thick cratonic lithosphere is a matter of debate. In particular, the percolation of hydrogen-bearing melts and fluids could potentially add hydrogen to the mantle lithosphere, weaken its olivines (the dominant mineral in mantle peridotite), and cause delamination of the lithosphere's base. The influence of metasomatism on hydrogen contents of cratonic mantle minerals can be tested in mantle xenoliths from the Slave Craton (Canada) because they show extensive evidence for metasomatism of a layered cratonic mantle. Minerals from mantle xenoliths from the Diavik mine in the Lac de Gras kimberlite area located at the center of the Archean Slave craton were analyzed by FTIR for hydrogen contents. The 18 peridotites, two pyroxenites, one websterite and one wehrlite span an equilibration pressure range from 3.1 to 6.6 GPa and include samples from the shallow (?145?km), oxidized ultra-depleted layer; the deeper (?145-180?km), reduced less depleted layer; and an ultra-deep (?180?km) layer near the base of the lithosphere. Olivine, orthopyroxene, clinopyroxene and garnet from peridotites contain 30-145, 110-225, 105-285, 2-105?ppm H2O, respectively. Within each deep and ultra-deep layer, correlations of hydrogen contents in minerals and tracers of metasomatism (for example light over heavy rare-earth-element ratio (LREE/HREE), high-field-strength-element (HFSE) content with equilibration pressure) can be explained by a chromatographic process occurring during the percolation of kimberlite-like melts through garnet peridotite. The hydrogen content of peridotite minerals is controlled by the compositions of the evolving melt and of the minerals and by mineral/melt partition coefficients. At the beginning of the process, clinopyroxene scavenges most of the hydrogen and garnet most of the HFSE. As the melt evolves and becomes enriched in hydrogen and LREE, olivine and garnet start to incorporate hydrogen and pyroxenes become enriched in LREE. The hydrogen content of peridotite increases with decreasing depth, overall (e.g., from 75 to 138?ppm H2O in the deep peridotites). Effective viscosity calculated using olivine hydrogen content for the deepest xenoliths near the lithosphere-asthenosphere boundary overlaps with estimates of asthenospheric viscosities. These xenoliths cannot be representative of the overall cratonic root because the lack of viscosity contrast would have caused basal erosion of lithosphere. Instead, metasomatism must be confined in narrow zones channeling kimberlite melts through the lithosphere and from where xenoliths are preferentially sampled. Such localized metasomatism by hydrogen-bearing melts therefore does not necessarily result in delamination of the cratonic root.
DS1998-1161
1998
AgrinierPhilpott, P., Agrinier, ScambelluriChlorine cycling during subduction of altered oceanic crustMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1169-70.MantleSubducion, Volatiles
DS2001-0658
2001
Agriniet, P.Laverne, C., Agriniet, P., Hermitte, D., Bohn, M.Chemical fluxes during hydrothermal alteration of 1200 m long section of dikes in the oceanic crust Hole 504B.Chemical Geology, Vol. 181,No. 1-4, pp. 73-98.GlobalDike - sheeted, ophiolite, dolerite, Geochemistry
DS201412-0004
2013
Agrosi, G.Agrosi, G., Tempesta, G., Scandael, E., Harris, J.W.Growth and post-growth defects in a diamond from Finsch mine ( South Africa).European Journal of Mineralogy, Vol. 25, pp. 551-559.Africa, South AfricaDeposit - Finsch
DS201604-0589
2016
Agrosi, G.Agrosi, G., Nestola, F., Tempestra, G., Bruno, M., Scandale, E., Harris, J.X-ray topographic study of a diamond from Udachnaya: implications for the genetic nature of inclusions.Lithos, Vol. 248-251, pp. 153-159.RussiaDeposit - Udachnaya

Abstract: In recent years, several studies have focused on the growth conditions of the diamonds through the analysis of the mineral inclusions trapped in them. In these studies, it is crucial to distinguish between protogenetic, syngenetic and epigenetic inclusions. X-ray topography (XRDT) can be a helpful tool to verify, in a non-destructive way, the genetic nature of inclusions in diamond. With this aim, a diamond from the Udachnaya kimberlite, Siberia, was investigated. The diamond, previously studied by Nestola et al. (2011), has anomalous birefringence and the two largest olivines have typical “diamond-imposed” shapes. The study of the topographic images shows that the diamond exhibits significant deformation fields related to post growth plastic deformation. The absence of dislocations starting from the olivine inclusions, and the dark contrasts around them represent the main results obtained by XRDT, contributing to the elucidation of the relationships between the diamond and the olivines at the micron-meter scale. The dark halo surrounding the inclusions was likely caused by the effect of different thermo-elastic properties between the diamond and the inclusions. The absence of dislocations indicates that the diamond-imposed morphology did not produce the volume distortion commonly associated with the entrapment of the full-grown inclusions and, thus, only based on such evidence, a syngenetic origin could be proposed. In addition, stepped figures optically observed at the interface between diamond and one of the olivines suggest processes of selective partial dissolution that would contribute to a change in the final morphology of inclusions. These results show that a diamond morphology may be imposed to a full-grown (protogenetic) olivine during their encapsulation, suggesting that the bulk of the inclusion is protogenetic, whereas its more external regions, close to the diamond-inclusion interface, could be syngenetic.
DS201705-0806
2017
Agrosi, G.Agrosi, G., Tempesta, G., Mele, D., Allegretta, I., Teranzo, R., Nestola, F.Multi analytical approach for non-destructuve analyses of a diamond from Udachnaya and its trapped inclusions: the first report of (fe, Ni) 1+xS machinawite sulphide in diamonds.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 5374 AbstractRussiaDeposit - Udachnaya

Abstract: The study of diamonds and the mineral inclusions trapped in them is of great interest for Earth science, since they can provide insight about deep mantle conditions and its evolution. The conventional techniques commonly used are destructive and thus do not allow the employment of different methods used simultaneously to obtain integrated and complementary results. Significant information about the growth conditions of diamonds and their inclusions still trapped within them can be preferably obtained by in situ investigation. In this study, we propose a multi-analytical approach, using a set of non-destructive techniques with conventional sources, to investigate one diamond from Udachnaya kimberlite (Siberia, Russia). The combined use of micro-X-ray Tomography, micro-X-ray Fluorescence, X-Ray Powder Diffraction and micro-Raman spectroscopy, allowed us to determine the spatial distribution of the inclusions, their chemical and mineralogical composition and, finally, the paragenetic suite, totally preserving the diamond host. The sample was also studied by means of X-ray Diffraction Topography to characterize the structural defects and to obtain genetic information about the growth history of the diamond. The combination of the different data provided a sort of «mapping» of a diamond. The X-Ray Topographic images show that the sample investigated exhibits plastic deformation. Actually, one set of {111} slip lamellae, corresponding to polysynthetic twinning, affect the whole sample. The tomographic images reveal that the primary inclusions, not observable optically, show a poly-faceted shape corresponding to an assemblage of tiny crystals. The chemical data display that the trapped minerals are mono-sulphides of Fe, Ni. The diagrams obtained by the X-Ray diffraction reveal that the inclusions mainly consist of an assemblage of tiny crystals of pentlandite and pyrrothite. Nevertheless, a thorough analysis of the diffraction data suggests the presence of another mono-sulphide of Fe,Ni: mackinawite. Raman spectra taken on these inclusions confirm, for the first time, the presence of this metastable phase as inclusion in diamond. The genetic implications of these results are discussed.
DS201712-2668
2017
Agrosi, G.Agrosi, G., Tempesta, G., Mele, D., Allegretta, I., Terzano, R., Shirery, S.B., Pearson, G.D., Nestola, F.Non-destructive, multi-method, internal analysis of multiple inclusions in a single diamond: first occurrence of mackinawite ( Fe,Ni)1+xSAmerican Mineralogist, Vol. 102, pp. 2235-2243.Russia, Siberiadeposit - Udachnaya

Abstract: A single gem lithospheric diamond with five sulfide inclusions from the Udachnaya kimberlite (Siberia, Russia) has been analyzed non-destructively to track the growth conditions of the diamond. Sulfides are the most abundant mineral inclusions in many lithospheric diamond crystals and are the most favorable minerals to date diamond crystals by Re-Os isotope systematics. Our investigation used non-destructive, micro-techniques, combining X-ray tomography, X-ray fluorescence, X-ray powder diffraction, and Raman spectroscopy. This approach allowed us to determine the spatial distribution of the inclusions, their chemical and mineralogical composition on the microscale, and, finally, the paragenetic association, leaving the diamond host completely unaffected. The sample was also studied by X-ray diffraction topography to characterize the structural defects of the diamond and to obtain genetic information about its growth history. The X-ray topographic images show that the sample investigated exhibits plastic deformation. One set of {111} slip lamellae, corresponding to polysynthetic twinning, affects the entire sample. Chemical data on the inclusions still trapped within the diamond show they are monosulfide solid solutions of Fe, Ni and indicate a peridotitic paragenesis. Micro-X-ray diffraction reveals that the inclusions mainly consist of a polycrystalline aggregate of pentlandite and pyrrothite. A thorough analysis of the Raman data suggests the presence of a further Fe, Ni sulfide, never reported so far in diamonds: mackinawite. The total absence of any oxides in the sulfide assemblage clearly indicates that mackinawite is not simply a “late” alteration of pyrrhotite and pentlandite due to secondary oxidizing fluids entering diamond fractures after the diamond transport to the surface. Instead, it is likely formed as a low-temperature phase that grew in a closed system within the diamond host. It is possible that mackinawite is a more common phase in sulfide assemblages within diamond crystals than has previously been presumed, and that the percentage of mackinawite within a given sulfide assemblage could vary from diamond to diamond and from locality to locality.
DS201712-2669
2017
Agrosi, G.Agrosi, G., Tempestra, G., Della Ventura, G., Guidi, M., Hutchison, M., Nimis, P., Nestola, F.Non-destructive in situ study of plastic deformations in diamonds: x-ray diffraction topography and micro-FTIR mapping of two super deep diamond crystals from Sao Luiz ( Juina, Brazil).Crystals, Vol. 7, #233South America, Brazildeposit - Juina

Abstract: Diamonds from Juina, Brazil, are well-known examples of superdeep diamond crystals formed under sublithospheric conditions and evidence would indicate their origins lie as deep as the Earth's mantle transition zone and the Lower Mantle. Detailed characterization of these minerals and of inclusions trapped within them may thus provide precious minero-petrogenetic information on their growth history in these inaccessible environments. With the aim of studying non-destructively the structural defects in the entire crystalline volume, two diamond samples from this locality, labelled JUc4 and BZ270, respectively, were studied in transmission mode by means of X-ray Diffraction Topography (XRDT) and micro Fourier Transform InfraRed Spectroscopy (µFTIR). The combined use of these methods shows a good fit between the mapping of spatial distribution of extended defects observed on the topographic images and the µFTIR maps corresponding to the concentration of N and H point defects. The results obtained show that both samples are affected by plastic deformation. In particular, BZ270 shows a lower content of nitrogen and higher deformation, and actually consists of different, slightly misoriented grains that contain sub-grains with a rounded-elongated shape. These features are commonly associated with deformation processes by solid-state diffusion creep under high pressure and high temperature.
DS201901-0001
2017
Agrosi, G.Agrosi, G., Tempesta, G., Della Ventura, G., Cestelli Guidi, M., Hutchison, M., Nimis, P., Nestola, F.Non-destructive in situ study of plastic deformation in diamonds: X-ray diffraction topography and uFTIR mapping of two super deep diamond crystals from Sao Luiz ( Juina, Brazil).Crystals MDPI, Vol. 7, 8, 11p. Doi.org/10. 3390/cryst7080233South America, Brazildeposit - Juina

Abstract: Diamonds from Juina, Brazil, are well-known examples of superdeep diamond crystals formed under sublithospheric conditions and evidence would indicate their origins lie as deep as the Earth’s mantle transition zone and the Lower Mantle. Detailed characterization of these minerals and of inclusions trapped within them may thus provide precious minero-petrogenetic information on their growth history in these inaccessible environments. With the aim of studying non-destructively the structural defects in the entire crystalline volume, two diamond samples from this locality, labelled JUc4 and BZ270, respectively, were studied in transmission mode by means of X-ray Diffraction Topography (XRDT) and micro Fourier Transform InfraRed Spectroscopy (µFTIR). The combined use of these methods shows a good fit between the mapping of spatial distribution of extended defects observed on the topographic images and the µFTIR maps corresponding to the concentration of N and H point defects. The results obtained show that both samples are affected by plastic deformation. In particular, BZ270 shows a lower content of nitrogen and higher deformation, and actually consists of different, slightly misoriented grains that contain sub-grains with a rounded-elongated shape. These features are commonly associated with deformation processes by solid-state diffusion creep under high pressure and high temperature.
DS201902-0304
2019
Agrosi, G.Nimis, P., Nestola, F., Schiazza, M., Reali, R., Agrosi, G., Mele, D., Tempesta, G., Howell, D., Hutchison, M.T., Spiess, R.Fe-rich ferropericlase and magnesiowustite inclusions reflecting diamond formation rather than ambient mantle.Geology, Vol. 47, 1., pp. 27-30.South America, Brazildeposit - Juina

Abstract: At the core of many Earth-scale processes is the question of what the deep mantle is made of. The only direct samples from such extreme depths are diamonds and their inclusions. It is commonly assumed that these inclusions reflect ambient mantle or are syngenetic with diamond, but these assumptions are rarely tested. We have studied inclusion-host growth relationships in two potentially superdeep diamonds from Juina (Brazil) containing nine inclusions of Fe-rich (XFe ?0.33 to ?0.64) ferropericlase-magnesiowüstite (FM) by X-ray diffractometry, X-ray tomography, cathodoluminescence, electron backscatter diffraction, and electron microprobe analysis. The inclusions share a common [112] zone axis with their diamonds and have their major crystallographic axes within 3°-8° of those of their hosts. This suggests a specific crystallographic orientation relationship (COR) resulting from interfacial energy minimization, disturbed by minor post-entrapment rotation around [112] due to plastic deformation. The observed COR and the relationships between inclusions and diamond growth zones imply that FM nucleated during the growth history of the diamond. Therefore, these inclusions may not provide direct information on the ambient mantle prior to diamond formation. Consequently, a “non-pyrolitic” composition of the lower mantle is not required to explain the occurrence of Fe-rich FM inclusions in diamonds. By identifying examples of mineral inclusions that reflect the local environment of diamond formation and not ambient mantle, we provide both a cautionary tale and a means to test diamond-inclusion time relationships for proper application of inclusion studies to whole-mantle questions.
DS201912-2766
2019
Agrosi, G.Agrosi, G., Tempesta, G., Mele, D., Caggiani, MC., Mangone, A., Della Ventura, G., Cestelli-Guidi, M., Allegretta, I., Hutchison, M.T., Nimis, P., Nestola, F.Multiphase inclusions associate with residual carbonate in a transition zone diamond from Juina, Brazil.Lithos, in press available, 31p. pdfSouth America, Brazildeposit - Juina

Abstract: Super-deep diamonds and their mineral inclusions preserve very precious information about Earth’s deep mantle. In this study, we examined multiphase inclusions entrapped within a diamond from the Rio Vinte e um de Abril, São Luiz area (Juina, Brazil), using a combination of non-destructive methods. Micro-Computed X-ray Tomography (?-CXRT) was used to investigate the size, shape, distribution and X-Ray absorption of inclusions and mapping by micro X-ray Fluorescence (?-XRF), ?-Raman Spectroscopy and micro-Fourier Transform Infrared Spectroscopy (?-FTIR) were used to determine the chemical and mineralogical composition of the inclusions. Four large inclusions enclosed in the N-rich diamond core consist of dominant ferropericlase-magnesiowüstite and locally exsolved magnesioferrite. FTIR maps, obtained integrating the band at 1430 cm?1, show also the presence of carbonates. A fifth large inclusion (ca 100 ?m) was remarkable because it showed a very unusual flask shape, resembling a fluid/melt inclusion. Based on ?CXRT tomography and ?-Raman mapping, the flask-shaped inclusion is polyphase and consists of magnetite and hematite partly replacing a magnesiowüstite core and small-volume of gas/vacuum. ?-Raman spectra on the same inclusion revealed local features that are ascribed to post-spinel polymorphs, such as maohokite or xieite, which are stable at P ? 18 GPa, and to huntite, a carbonate with formula CaMg3(CO3)4. This represents the first finding of maohokite and huntite in diamond. We interpret the composition of the inclusions as evidence of formation of ferropericlase-magnesiowüstite and diamond in a carbonate-rich environment at depths corresponding at least to the Transition Zone, followed by oxidation of ferropericlase-magnesiowüstite by reaction with relatively large-volume entrapped melt during diamond ascent.
DS201212-0007
2012
Agrusta, R.Agrusta, R., Tommasi, A.Lithosphere thinning by small scale convection in a plume fed low viscosity layer beneath a moving plate.emc2012 @ uni-frankfurt.de, 1p. AbstractMantlePlume
DS201602-0187
2015
Agrusta, R.Agrusta, R., Tommasi, A., Arcay, D., Gonzalez, A., Gerya, T.How partial melting affects small-scale convection in a plume-fed sublithospheric layer beneath fast-moving plates.Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 11, Nov. pp. 3924-3945.MantleConvection

Abstract: Numerical models show that small-scale convection (SSC) occurring atop a mantle plume is a plausible mechanism to rejuvenate the lithosphere. The triggering of SSC depends on the density contrast and on the rheology of the unstable layer underlying the stagnant upper part of the thermal boundary layer (TBL). Partial melting may change both properties. We analyze, using 2-D numerical simulations, how partial melting influences the dynamics of time-dependent SSC instabilities and the resulting thermo-mechanical rejuvenation of an oceanic plate moving atop of a plume. Our simulations show a complex behavior, with acceleration, no change, or delay of the SSC onset, due to competing effects of the latent heat of partial melting, which cools the plume material, and of the buoyancy increase associated with both melt retention and depletion of residue following melt extraction. The melt-induced viscosity reduction is too localized to affect significantly SSC dynamics. Faster SSC triggering is promoted for low melting degrees (low plume temperature anomalies, thick lithosphere, or fast moving plates), which limit both the temperature reduction due to latent heat of melting and the accumulation of depleted buoyant residue in the upper part of the unstable layer. In contrast, high partial melting degrees lead to a strong temperate decrease due to latent heat of melting and development of a thick depleted layer within the sublithospheric convecting layer, which delay the development of gravitational instabilities. Despite differences in SSC dynamics, the thinning of the lithosphere is not significantly enhanced relatively to simulations that neglect partial melting.
DS201704-0615
2017
Agrusta, R.Agrusta, R., Goes, S., van Hunen, J.Subducting slab transition zone interaction: stagnation, penetration and mode switches.Earth and Planetary Science Letters, Vol. 464, pp. 10-23.MantleSubduction

Abstract: Seismic tomography shows that subducting slabs can either sink straight into the lower mantle, or lie down in the mantle transition zone. Moreover, some slabs seem to have changed mode from stagnation to penetration or vice versa. We investigate the dynamic controls on these modes and particularly the transition between them using 2D self-consistent thermo-mechanical subduction models. Our models confirm that the ability of the trench to move is key for slab flattening in the transition zone. Over a wide range of plausible Clapeyron slopes and viscosity jumps at the base of the transition zone, hot young slabs (25 Myr in our models) are most likely to penetrate, while cold old slabs (150 Myr) drive more trench motion and tend to stagnate. Several mechanisms are able to induce penetrating slabs to stagnate: ageing of the subducting plate, decreasing upper plate forcing, and increasing Clapeyron slope (e.g. due to the arrival of a more hydrated slab). Getting stagnating slabs to penetrate is more difficult. It can be accomplished by an instantaneous change in the forcing of the upper plate from free to motionless, or a sudden decrease in the Clapeyron slope. A rapid change in plate age at the trench from old to young cannot easily induce penetration. On Earth, ageing of the subducting plate (with accompanying upper plate rifting) may be the most common mechanism for causing slab stagnation, while strong changes in upper plate forcing appear required for triggering slab penetration.
DS201707-1329
2017
Agrusta, R.Goes, S., Agrusta, R., van Hunen, J., Garel, F.Subduction - transition zone interaction: a review.Geosphere, Vol. 13, 3, pp. 644-8.Mantlesubduction

Abstract: As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20–50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of –1 to –2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ?2 orders of magnitude higher than background mantle (effective yield stresses of 100–300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.
DS201901-0035
2017
Agrusta, R.Goes, S., Agrusta, R., van Hunen, J., Garel, F.Subduction - transition zone interaction: a review.Geosphere, Vol. 13, 3, pp. 644-664.Mantlesubduction

Abstract: As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20-50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of -1 to -2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ?2 orders of magnitude higher than background mantle (effective yield stresses of 100-300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.
DS200812-0006
2008
AGS LaboratoriesAGS Laboratories'The Real Ideal' - AGS Laboratories defines the Real Ideal cut diamond.AGS Laboratories, July 21, 1p.TechnologyNews item - American Gem Society Laboratories
DS1994-0028
1994
AGSOAGSORegolith conference abstract volumeAgso, $ 15.00AustraliaBook ad -regolith, Laterites, ferricretes, silcretes
DS1994-0029
1994
AGSOAGSO12 map Kalimantan 1: 250, 000 geoscientific series completed by AGSOAus Geo News, No. 22, June p. 8.GlobalMap -ad
DS1995-0010
1995
AGSOAGSOThe regolith .... featured thematic issueAgso Journal Of Australian Geol. And Geophysics, AustraliaBook -ad, Regolith thematic issue
DS1996-0009
1996
AGSOAGSOAustralian impact structuresAgso, Vol. 16, No. 4, pp. 371-620AustraliaImpact structures, Table of contents
DS1996-0010
1996
AGSOAGSOMaps- new 1:100, 000 geological maps of the East KimberleyAustralian Geological Survey Organization, Maps, paper or digitalAustraliaMaps, Kimberley region, Halls Creek
DS1997-0009
1997
AGSOAGSODepth to magnetic basement mapsAgso, AustraliaExploration, Basement
DS1997-0010
1997
AGSOAGSOComparative Paleoproterozoic tectonics and metallogenesis in Australian and Fennoscandian shieldsAgso, Australia, Fennoscandia, Baltic shieldBook - ad, Metallogeny
DS201112-0008
2011
Agterberg, F.Agterberg, F.A modified weights-of-evidence method for regional mineral resource estimation.Natural Resources Research, Vol.20, 2, pp. 95-TechnologySpatial modeling, logistic regression
DS201112-0009
2011
Agterberg, F.Agterberg, F.A modified weights of evidence method for regional mineral resource estimation.Natural Resources Research, Vol. 20, 2, June pp. 95-TechnologyEconomics - not specific to diamonds
DS1993-0014
1993
Agterberg, F.P.Agterberg, F.P., Cheng, Q., Wright, D.F.Fractal modelling of mineral depositsApcom Xxiv, pp. 43-53British ColumbiaGeostatistics, Mineral potential, Deposit -Sulphurets
DS1993-0559
1993
Agterberg, F.P.Goodacre, A.K., Bonham-Carter, G.F., Agterberg, F.P., Wrightm D.F.A statistical analysis of the spatial association of seismicity with drainage patterns and magnetic anomalies in western QuebecTectonophysics, Vol. 217, No. 3-4, January 30, pp. 285-306QuebecGeomorphology, Geophysics -seismics
DS1995-0011
1995
Agterberg, F.P.Agterberg, F.P.Multifractal modeling of the sizes and grades of giant and supergiantdepositsInternational Geology Review, Vol. 37, No. 1, Jan. pp. 1-8GlobalGiant ore deposits, Model -fractals
DS1997-0011
1997
Agterberg, F.P.Agterberg, F.P.Multifractal modelling of the sizes and grades and supergiant depositsGlobal Tectonics and Metallogeny, Vol. 6, No. 2, March pp. 131-136GlobalModelling - fractals, discoveries, Deposits - giant
DS200612-1302
2006
Agterberg, F.P.Sim, B.L., Agterberg, F.P.A conceptual model for kimberlite emplacement by solitary interfacial mega-waves on the core mantle boundary.Journal of Geodynamics, Vol. 41, 5, July, pp. 451-461.MantleConvection, magnetics, D layer Rogue waves ULVZ
DS200612-1303
2006
Agterberg, F.P.Sim, B.L., Agterberg, F.P.A conceptual model for kimberlite emplacement by solitary interfacial megawaves on the core mantle boundary.Journal of Geodynamics, Vol. 41, 5, pp. 451-461.MantleGeophysics
DS200412-0007
2003
Ague, J.Ague, J.Fluid flow in the deep crust.Treatise on Geochemistry, Holland Editor, Volume 3, pp. 195-228.MantleGeochemistry, chemical transport
DS201412-0043
2013
Ague, J.I.Baxter, E.F., Caddick, M.J., Ague, J.I.Garnet: common mineral, uncommonly useful.Elements, Vol. 9, 6, Dec. pp. 415-420.MantleGarnet mineralogy
DS1999-0005
1999
Ague, J.J.Ague, J.J., Rye, D.M.Simple models of CO2 release from metacarbonates with implications for interpretation of directions...Journal of Petrology, Vol. 40, No. 9, Sept. pp. 1443-Mantle, crustCarbonatization, Model - Flow
DS200612-1530
2006
Ague, J.J.Wilbur, D.E., Ague, J.J.Chemical disequilibrium during garnet growth: Monte Carlo simulations of natural crystal morphologies.Geology, Vol. 34, 8, August pp. 689-692.TechnologyMetamorphism, crystal growth - not specific to diamond
DS200912-0463
2009
Ague, J.J.Lyubetskaya, T., Ague, J.J.Effect of metamorphic reactions on thermal evolution in collisional orogens.Journal of Metamorphic Geology, Vol. 27, 8, pp. 579-600.MantleGeothermometry
DS201412-0005
2013
Ague, J.J.Ague, J.J., Carlson, W.D.Metamorphism as garnet sees it: the kinetics of nucleation and growth, equilibrium, and diffusional relaxation.Elements, Vol. 9, 6, Dec. pp. 439-445.MantleCrystallography
DS201501-0001
2014
Ague, J.J.Ague, J.J.Deep carbon: subduction goes organic.Nature Geoscience, 2p.MantleCarbon

Abstract: Aqueous subduction-zone fluids contain CO2 and methane. New calculations indicate that these fluids also host a wide array of organic carbon species, in concentrations sufficient to influence the deep carbon cycle.
DS201711-2507
2017
Ague, J.J.Chu, X., Ague, J.J., Podladchikov, Y.Y., Tian, M.Ultrafast eclogite formation via melting induced overpressure.Earth and Planetary Science Letters, Vol. 479, pp. 1-17.Mantleeclogite

Abstract: The conventional wisdom holds that metamorphic reactions take place at pressures near-lithostatic so that the thermodynamic pressure, reflected by the mineral assemblage, is directly correlated with depth. On the other hand, recent field-based observations and geodynamic simulations suggest that heterogeneous stress and significant pressure deviations above lithostatic (overpressure) can occur in Earth's crust. Here we show that eclogite, normally interpreted to form at great depths in subduction zones and Earth's mantle, may form at much shallower depths via local overpressure generated in crustal shear zones. The eclogites studied crop out as lenses hosted by felsic paragneiss in a sheared thrust slice and represent a local pressure and temperature anomaly in the Taconic orogenic belt, southern New England. Sharply-defined chemical zones in garnet, which record ?5 kbar pressure rise and fall accompanied by a temperature increase of 150-200?°C, demonstrate extremely short timescales of diffusion. This requires anomalously fast compression (?500 yrs) and decompression. We use coupled phase equilibria and garnet diffusion forward modeling to fit the observed garnet profiles and test the likely paths using a Monte Carlo-type approach, accounting for off-center sectioning of garnet. The simulation shows that a ?5 kbar pressure increase after the temperature peak is necessary to reproduce the garnet zoning. Remarkably, this post-peak-T compression (from 9 kbar to 14 kbar) lasted only ?500 yrs. If the compression was due to burial along a lithostatic pressure gradient, the descent speed would exceed 30 m?yr?1, defying any observed or modeled subduction rates. Local overpressure in response to partial melting in a confined volume (Vrijmoed et al., 2009) caused by transient shear heating can explain the ultra-fast compression without necessitating burial to great depth.
DS202005-0741
2020
Ague, J.J.Keller, D., Ague, J.J.Quartz, mica, and amphibole exsolution from majoritic garnet reveals ultra-deep sediment subduction, Appalachian region.Science Advances, doi. 10.1126/sciadv.aay5178 13p. PdfUnited States, ConnecticutUHT, HPG

Abstract: Diamond and coesite are classic indicators of ultrahigh-pressure (UHP; ?100-kilometer depth) metamorphism, but they readily recrystallize during exhumation. Crystallographically oriented pyroxene and amphibole exsolution lamellae in garnet document decomposed supersilicic UHP majoritic garnet originally stable at diamond-grade conditions, but majoritic precursors have only been quantitatively demonstrated in mafic and ultramafic rocks. Moreover, controversy persists regarding which silicates majoritic garnet breakdown produces. We present a method for reconstructing precursor majoritic garnet chemistry in metasedimentary Appalachian gneisses containing garnets preserving concentric zones of crystallographically oriented lamellae including quartz, amphibole, and sodium phlogopite. We link this to novel quartz-garnet crystallographic orientation data. The results reveal majoritic precursors stable at ?175-kilometer depth and that quartz and mica may exsolve from garnet. Large UHP terranes in the European Caledonides formed during collision of the paleocontinents Baltica and Laurentia; we demonstrate UHP metamorphism from the microcontinent-continent convergence characterizing the contiguous and coeval Appalachian orogen.
DS201709-2043
2017
Aguiar, A.L.Pimenta Martins, L.G., Matos, M.J.S., Paschoal, A.R., Freire, P.T.C., Andrade, N.F., Aguiar, A.L., Kong, J., Neves, B.R.A., de Oliveira, A.B., Mazzoni, M.S.C., Souza Filhio, A.G., Cancad, L.G.Raman evidence for pressure induced formation of diamondene.Nature Communications, Vol. 8, 9p.Technologydiamondene

Abstract: Despite the advanced stage of diamond thin-film technology, with applications ranging from superconductivity to biosensing, the realization of a stable and atomically thick two-dimensional diamond material, named here as diamondene, is still forthcoming. Adding to the outstanding properties of its bulk and thin-film counterparts, diamondene is predicted to be a ferromagnetic semiconductor with spin polarized bands. Here, we provide spectroscopic evidence for the formation of diamondene by performing Raman spectroscopy of double-layer graphene under high pressure. The results are explained in terms of a breakdown in the Kohn anomaly associated with the finite size of the remaining graphene sites surrounded by the diamondene matrix. Ab initio calculations and molecular dynamics simulations are employed to clarify the mechanism of diamondene formation, which requires two or more layers of graphene subjected to high pressures in the presence of specific chemical groups such as hydroxyl groups or hydrogens.
DS202108-1268
2021
Aguila, M.Aguila, M.Diamonds are a physicist's best friend. Imperfections in jewels used as sensors for new quantum materials. See full ref. McLaughlinucsdnews.ucsd.edu, June 17, 1p. Overview Globaldiamond inclusions

Abstract: Defects found in diamonds are typically received as unwelcome news to the discerning jewelry shopper. But for some physicists, diamond imperfections offer a new opportunity to push the boundaries of futuristic devices that could become the backbone of tomorrow’s computers. UC San Diego Department of Physics Assistant Professor Chunhui Rita Du is a condensed matter experimentalist whose research takes advantage of impurities in diamonds. Du’s research group leverages the red, yellow and blue colors that result from diamond defects to develop sensors that can evaluate the properties of specialized materials down to the nanometer level.
DS1910-0549
1918
Aguilar y santillan, R.Aguilar y santillan, R.Bibliografia Geologica Y Minera de la Republica MexicanaMexico Department Minas Bol. Minero, 97P.MexicoBlank
DS1910-0231
1912
Aguillon, L.Aguillon, L.Note sur le Regime Legal des Mines Au Congo BelgeAnnual DES Mines, Vol. 1, PT. 1, 24P.Democratic Republic of CongoMining, History, Law
DS2000-0225
2000
Aguirre-Diaz, G.J.Delgado Granados, H., Aguirre-Diaz, G.J., Stock, J.M.Cenozoic tectonics and volcanism of MexicoGeological Society of America Special paper, No. 334, 300p.MexicoBook - table of contents
DS1987-0003
1987
Agyei, E.K.Agyei, E.K., Van Landewijk, J.E.J.M., Armstrong, R.L., Harakal, J.E.Rubidium-strontium and potassium-argon geochronometry of southeasternGhanaJournal of African Earth Science, Vol. 6, No. 2, pp. 153-161GhanaCarbonatite
DS2001-0579
2001
AhallKarlstrom, R.E., Ahall, Harlam, Williams, McLellandLong lived (1.8-1.0) Ga convergent Orogen in southern Laurentia: its extensions to Australia and Baltica....Precambrian Research, Vol. 111, No. 1-4, pp. 5-30.Australia, Norway, BalticaRodinia - tectonics, Orogeny
DS1997-0012
1997
Ahall, K.I.Ahall, K.I., Gower, C.F.The Gothian and Labradorian orogens: variations in accretionary tectonismalong Paleoproterozoicmargin..Gff., Vol. 119, pp. 181-191.Scandinavia, LabradorOrogeny, Laurentia-Baltica
DS1998-0013
1998
Ahall, K.I.Ahall, K.I., Connelly, J.Intermittent 1.53 - 1.13 Ga magmatism in western Baltica: age constraints and correlations...Precambrian Research, Vol. 92, No. 1, Sept. 1, pp. 1-20.Europe, Baltic ShieldSupercontinent, geochronology, Tectonics
DS1998-0014
1998
Ahall, K.I.Ahall, K.I., Cornell, D.H., Armstrong, R.Ion probe zircon dating of metasedimentary units across the Skagerrak: new constraints early Mesoproterozoic.Precambrian Research, Vol. 87, No. 3-4, Feb. 1, pp. 117-134Sweden, Norway, Finland, Baltic ShieldGeochronology
DS2000-0009
2000
Ahall, K.I.Ahall, K.I., Connelly, J.N., Brewer, T.S.Episodic rapakivi magmatism due to distal orogenesis? correlation of 1.69-1.50 Ga orogenic and inboard....Geology, Vol. 28, No. 9, Sept. pp. 823-6.Baltic Shield, Norway, Sweden, Finland, Russia, KolaMagmatism, Orogenic growth
DS2000-0010
2000
Ahall, K.I.Ahall, K.I., Larson, S.A.Growth related 1.85-1.55 Ga magmatism in the Baltic Shield: a review addressing tectonics characteristics.Gff., Vol. 122, pp. 193-206.Finland, Norway, Sweden, Baltic States, FennoscandiaTransscandinavian Igneous Belt, Magmatism, Tectonics
DS2001-0010
2001
Ahall, K.I.Ahall, K.I., Brewer, T.S., Connelly, J.N.Deciphering the complex accretionary growth history of the Baltic Shield between 1.7 - 1.5 Ga and links...Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.1, abstract.Baltic Shield, Baltica, LaurentiaMagmatism - intracontinental
DS2002-0205
2002
Ahall, K.I.Brewer, T.S., Ahall, K.I., Darbyshire, D., Menuge, J.Geochemistry of late Mesoproterozoic volcanism in southwestern Scandinavia: implications for ...plate..Journal of Geological Society of London, Vol. 159, 2, pp. 129-44.ScandinaviaSveconorwegian Grenvillian plate tectonic models, Tectonics
DS1997-0013
1997
Aharonov, E.Aharonov, E., et al.Three dimensional flow and reaction in porous media: implications forearth's mantle and sedimentary basinsJournal Geophys. Research, Vol. 102, No. 7, July 10, pp. 14821-34.MantleGeophysics, Flow
DS2001-1112
2001
Aharonov, E.Spiegelman, M., Kelemen, P.B., Aharonov, E.Causes and consequences of flow organization during melt transport: the reaction infiltration instabilityJournal of Geophysical Research, Vol. 106, No.2, Feb.10, pp. 2061-78.MantleCompaction media, Melting
DS1989-0011
1989
Ahern, J.L.Ahern, J.L., Dikeou, P.J.Evolution of the lithosphere beneath the Michigan basinEarth and Planetary Science Letters, Vol. 95, No. 1, /2, October pp. 73-84MichiganTectonics, Mantle
DS2001-0011
2001
Ahijado, A.Ahijado, A., Casillas, R., Hernandez-Pacheco, A.The dike swarms of the Amanay Massif, Fuerteventura, Canary Islands (Spain)Journal of African Earth Sciences, Vol. 19, No. 3, Apr. pp.333-46.GlobalAlkaline rocks, Dike Swarms
DS200412-0438
2004
Ahijado, A.Demeny, A., Vennemann, T.W., Ahijado, A., et al.Oxygen isotope thermometry in carbonatites, Fuerteventura Canary Islands, Spain.Mineralogy and Petrology, Vol. 80, 3-4, March pp. 155-172.Europe, Canary IslandsCarbonatite
DS200812-0281
2008
Ahijado, A.Demeny, A., Casilla, R., Ahijado, A., De la Nuez, J., Milton, A.J., Nagy, G.Carbonate xenoliths in La Palma: carbonatite or alteration product?Chemie der Erde, Vol. 68, 4, pp. 369-381.Europe, SpainCarbonatite
DS200812-0282
2008
Ahijado, A.Demeny, A., Casillas, R., Ahijado, A., La Nuez, J.de, Milton, J.A., Nagy, G.Carbonate xenoliths in La Palma: carbonatite or alteration product?Chemie der Erde, Vol. 68, 4, pp. 369-381.Europe, Canary IslandsGeochronology
DS201112-0152
2011
Ahijado, A.Casillas, R., Demeny, A., Nagy, G., Ahijado, A., Fernandez, C.Metacarbonatites in the Basal Complex of Fuerteventura ( Canary Islands). The role of fluid/rock interactions during contact metamorphism and anatexis.Lithos, Vol. 125, pp. 503-520.Europe, Canary IslandsCarbonatite
DS201806-1209
2018
Ahline, N.Ardon, T., Ahline, N.Fancy deep brown-orange CVD synthetic diamond. 0.56 ctGems & Gemology, Vol. 54, 1, p. 64Technologysynthetics
DS202104-0564
2021
Ahline, N.Ahline, N., Ardon, T., Overlin, S.D-Z Diamonds ( from the print copy of article in Gems & Gemology)GIAcommunications @gia.edu, gia.org and knowledge sessionsGlobaldiamond genesis

Abstract: G&G’s most recent issue captured the past, present and future of the gem industry - with an overview of European royal jewelry sales (including the sale of Marie Antoinette’s jewelry), in-depth coverage of D-Z diamond knowledge (such as causes of color and formation) and a journey into Vietnamese pearl farming. Tune in as G&G contributors Troy Ardon and Nicole Ahline touch upon these and other highlights from the most recent publication of GIA’s prestigious scientific journal.
DS201312-0011
2013
Ahlqvist, O.Ahlqvist, O., Harvey, F., Ban, H., Chen, W., Fonanella, S., Guo, M.,Singh, N.Making journal articles 'live': turning academic writing into scientific dialog.Geojournal, Vol. 78, 1, pp. 61-68.TechnologyKnowledge dissemination
DS1950-0248
1956
Ahmad, F.Ahmad, F.On the Source of the Panna Diamonds and the Nature of the Majhgawan Plug.Indian Sci. Congr. 43rd. Session Proceedings, ABSTRACT.India, Madhya PradeshBlank
DS1980-0117
1980
Ahmad, S.N.Ehrenberg, S.N., Ahmad, S.N., Perry, E.C.JR.Oxygen Isotopic Compositions of Garnet Granulites from Colorado Plateau Diatremes.Eos, Vol. 61, No. 17, APRIL 22ND. P. 387.United States, Colorado PlateauBlank
DS200412-0861
2004
Ahmad, T.Hussein, M.F., Mondal, MEA, Ahmad, T.Petrological and geochemical characteristics of Archean gneisses and granitoids from Bastar Craton, central India - implicationGondwana Research, Vol. 7, 2, pp. 531-538.IndiaSubduction
DS200812-0007
2008
Ahmad, T.Ahmad, T., Deb, M., Tarney, J., Raza, M.Proterozoic mafic volcanism in the Aravalli Delhi orogen, northwest India: geochemistry and tectonic framework.Journal of Geological Society of India, Vol. 72, 1, pp. 93-112.IndiaTectonics
DS200812-0008
2008
Ahmad, T.Ahmad, T., Jayananda, M.Plutonism and Precambrian magmatism in India.Glimpses of Geoscience Research in India, The Indian report to IUGS 2004-08, pp. 160-173.IndiaShield areas
DS200812-0760
2008
Ahmad, T.Mondal, M.E.A., Chandra, R., Ahmad, T.Precambrian mafic magmatism in Bundelk hand Craton.Journal of Geological Society of India, Vol. 72, 1, pp. 113-122.IndiaMagmatism
DS200812-1107
2008
Ahmad, T.Srivastava, R.K., Ahmad, T.Precambrian mafic magmatism in the Indian Shield: an introduction.Journal of the Geological Society of India, Vol. 72, 1, pp. 9-14.IndiaMagmatism
DS201012-0512
2010
Ahmad, T.Mondal, M.E.A., Hussain, M.F., Ahmad, T.Mafic dyke swarms of central Indian shield: implications for a pre-Rodinia supercontinent assembly.International Dyke Conference Held Feb. 6, India, 1p. AbstractIndiaDeposit - Bunder
DS202102-0200
2020
Ahmad, T.Joshi, K.B., Sorcar, N., Pant, N.C., Nandakumar, V., Ahmad, T., Tomson, J.K.Characterization of multiple episodes of melt generation from lower crust during Archean using amphibole composition.Episodes, doi.org/10.18814/ epiiugs/2020 /020092 24p. PdfIndiaCraton - Bundelkhand

Abstract: Spatial association of tonalite trondhjemite granodiorites (TTGs) and high-K granitoids (anatectic and hybrid granites) from the Bundelkhand Craton (BC), Central India, is well known. Geochronological data indicates multiple episodes of formation of these high silica rocks showing a spread of ~1 Ga during Paleo to Neoarchaean. In the present study, we try to understand the evolution of TTGs and high-K granitoids (hybrid granites) from the BC using amphibole composition. The amphibole in both TTGs and high-K granitoids (hybrid granites) from the BC are characterised as magmatic, zoned, and calcic in nature. We find that the amphibole composition of the studied rocks is dominated by magnesiohornblende along with less common occurrence of tschermakite, magnesiohastingsite and edenite. Overall variation in amphibole compositions in terms of exchange vectors show a well defined linear trend (except for a late stage low-grade metamorphic readjustment), which suggests melt control over crystallization and evolution of amphibole chemistry. Moreover, the geothermobarometric analysis points towards higher pressure formation of TTGs in comparison to that of high-K granitoids (hybrid granites), with nearly the same temperature conditions in both the cases. Combining all our findings, we propose the evolution of the two considered rock types through lower crustal melting under varying PH2O conditions at different depths of emplacement.
DS1998-0015
1998
Ahmadian, A.Ahmadian, A., Kitamura, M.Morphology of spinel twinned crystals of natural diamondIma 17th. Abstract Vol., p. A 83, abstractSouth Africa, RussiaDiamond morphology
DS2002-0011
2002
Ahmadjan, A.Ahmadjan, A., Kitamura, M.Re-entrant and salient corner effects of spinel twinned natural diamond18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.147.MantleDiamond - morphology
DS1950-0001
1950
Ahman, E.Ahman, E.Ett Fynd Av Frisk Olivin I Kimberlit Fran Kalix Skargard I Norrbotten.Geol. Foren. Forhandl., Vol. 72, PP. 207-211.Sweden, ScandinaviaKimberlite, Alnoite
DS1950-0050
1951
Ahman, E.Ahman, E.Ett Blockfynd Av Ovanlig Art Fran Kalix SkargardGeol. Foren. Forhandl., Vol. 73, PP. 603-607.Sweden, ScandinaviaAlnoite
DS1960-0002
1960
Ahman, E.Ahman, E.The Kalix AreaInternational Geological Congress, 21 ST., GUIDE BOOK A 32 and C 26, PP. 23-26.Sweden, ScandinaviaAlnoite
DS1960-0772
1967
Ahman, E.Ahman, E.Vastra Graddmanhallan Island, Kalix Archipelago, NorrbottenGeol. Foren. Forhandl., Vol. 89, PT. 1, No. 528, PP. 50-61.Norway, ScandinaviaPetrography
DS1981-0254
1981
Ahman, E.Kresten, P., Ahman, E., Brunfelt, A.O.Alkaline Ultramafic Lamprophyres and Associated Carbonatite dykes from the Kalix Area, Northern Sweden.Geologische Rundschau, Vol. 70, No. 3, PP. 1215-1231.Sweden, ScandinaviaAlnoite
DS201511-1819
2014
Ahmat, A.L.Ahmat, A.L.The Ellendale diamond field: exploration history, discovery, geology and mining.Australian Gemmologist, Vol. 24, 12, pp. 280-288.AustraliaDeposit - Ellendale

Abstract: The Ellendale diamond field in West Kimberley is one of only three hard-rock diamond mine locations in Australia. Though not the first Australian diamond mine, Ellendale was the country’s first hard-rock deposit. It holds a special place in world diamond history as it led in November 1976 to the recognition of a new host-rock for diamond, olivine lamproite. Up until that time, commercial-sized diamonds were considered to be sourced only from kimberlite. The Ellendale lamproites are geologically very young, only 22 Ma (million of years) old. Within several years of the initial discovery, some 46 lamproite pipes were found at Ellendale. By 1980, 38 of these pipes had been assessed for their diamond content. More than two decades later, geologists from the Kimberley Diamond Company (KDC) recognized eluvial diamond enrichment over these pipes. After a lengthy legal battle, they wrested the Ellendale mining lease from the Ashton Joint Venture and commenced mining there in May 2002. Ellendale is recognized as a source of high-value fancy yellow diamonds. These high priced stones have been marketed through a special deal with Tiffany & Co since 2009. But the future of mining there is tenuous. Ellendale 4 was closed in 2009, and the high Australian dollar, combined with dwindling reserves, may jeopardize the survival of Ellendale 9.
DS201112-0024
2011
Ahmed, A.H.Arai, S., Ahmed, A.H., Miura, M.Ultrahigh pressure podiform chromitites as a possible deep recycled material.Goldschmidt Conference 2011, abstract p.447.Asia, Tibet, OmanUHP
DS201502-0037
2015
Ahmed, A.H.Ahmed, A.H., Habtoor, A.Heterogeneously depleted Precambrian lithosphere deduced from mantle peridotites and associated chromitite deposits of Al, Ays ophiolite, northwestern Arabian shield, Saudi Arabia.Ore Geology Reviews, Vol. 67, pp. 279-296.Africa, Saudi ArabiaPeridotite

Abstract: The mantle section of Al'Ays ophiolite consists of heterogeneously depleted harzburgites, dunites and large-sized chromitite pods. Two chromitite-bearing sites (Site1 and Site2), about 10 km apart horizontally from one another, were examined for their upper mantle rocks. Cr-spinels from the two sites have different chemistry; Cr-rich in Site1 and Al-rich in Site2. The average Cr-ratio = (Cr/(Cr + Al) atomic ratio) of Cr-spinels in harzburgites, dunites and chromitites is remarkably high 0.78, 0.77 and 0.87, respectively, in Site1, compared with those of Site2 which have intermediate ratio averages 0.5, 0.56 and 0.6, respectively. The platinum-group elements (PGE) in chromitites also show contrasting patterns from Site1 to Site2; having elevated IPGE (Os, Ir, Ru) and strongly depleted in PPGE (Rh, Pt, Pd) with steep negative slopes in the former, and gentle negative slopes in the latter. The oxygen fugacity (?log fO2) values deduced from harzburgites and dunites of Site1 show a wide variation under reducing conditions, mostly below the FMQ buffer. The Site2 harzburgites and dunites, on the other hand are mostly above the FMQ buffer. Two magmatic stages are suggested for the lithospheric evolution of Al'Ays ophiolite in response to a switch of tectonic setting. The first stage produced a peridotites–chromitites suite with Al-rich Cr-spinels, possibly beneath a mid-ocean ridge setting, or most likely in back-arc rift of a supra-subduction zone setting. The second stage involved higher degrees of partial melting, produced a peridotites–chromitites suite with Cr-rich Cr-spinels, possibly in a fore-arc setting. The coexistence of compositionally different mantle suites with different melting histories in a restricted area of an ophiolite complex may be attributable to a mechanically juxtaposed by mantle convection during recycling. The mantle harzburgites and dunites are apt to be compositionally modified during recycling process; being highly depleted (Site1 case) than their original composition (Site2 case).
DS201601-0001
2016
Ahmed, A.H.Ahmed, A.H., Moghazi, A.K.D., Moufti, M.R., Dawood, Y.H., Ali, K.A.Nature of the lithospheric mantle beneath the Arabian shield and genesis of Al-spinel micropods: evidence from the mantle xenoliths of Harrat Kishb, western Saudi Arabia.Lithos, Vol. 240-243, pp. 119-139.Africa, Saudi ArabiaPeridotite

Abstract: The Harrat Kishb area of western Saudi Arabia is part of the Cenozoic volcanic fields in the western margin of the Arabian Shield. Numerous fresh ultramafic xenoliths are entrained in the basanite lava of Harrat Kishb, providing an opportunity to study the nature and petrogenetic processes involved in the evolution of the lithospheric mantle beneath the Arabian Shield. Based on the petrological characteristics and mineralogical compositions, the majority of the mantle xenoliths (~ 92%) are peridotites (lherzolites and pyroxene-bearing harzburgites); the remaining xenoliths (~ 8%) are unusual spinel-rich wehrlites containing black Al-spinel micropods. The two types of mantle xenoliths display magmatic protogranular texture. The peridotite xenoliths have high bulk-rock Mg#, high forsterite (Fo90-Fo92) and NiO (0.24-0.46 wt.%) contents of olivine, high clinopyroxene Mg# (0.91-0.93), variable spinel Cr# (0.10-0.49, atomic ratio), and approximately flat chondrite-normalized REE patterns. These features indicate that the peridotite xenoliths represent residues after variable degrees of melt extraction from fertile mantle. The estimated P (9-16 kbar) and T (877-1227 °C) as well as the oxidation state (?logfO2 = ? 3.38 to ? 0.22) under which these peridotite xenoliths originated are consistent with formation conditions similar to most sub-arc abyssal-type peridotites worldwide. The spinel-rich wehrlite xenoliths have an unusual amount (~ 30 vol.%) of Al-spinel as peculiar micropods with very minor Cr2O3 content (< 1 wt.%). Olivines of the spinel-rich wehrlites have low-average Fo (Fo81) and NiO (0.18 wt.%) contents, low-average cpx Mg# (0.79), high average cpx Al2O3 content (8.46 wt.%), and very low-average spinel Cr# (0.01). These features characterize early mantle cumulates from a picritic melt fraction produced by low degrees of partial melting of a garnet-bearing mantle source. The relatively high Na2O and Al2O3 contents of cpx suggest that the spinel-rich wehrlites are formed under high P (11-14 kbar), T (1090-1130 °C), and oxidation state (?logfO2 FMQ = + 0.14 to + 0.37), which occurred slightly below the crust-mantle boundary. The REE patterns of spinel-rich wehrlites are almost similar to those of the associated peridotite xenoliths, which confirm at least a spatial genetic linkage between them. Regarding the formation of Al-spinel micropods in spinel-rich wehrlite cumulates, it is suggested that the melt-rock reaction mechanism is not the only process by which podiform chromitite is formed. Early fractionation of picritic melts produced by partial melting of a mantle source under high P-T conditions could be another mechanism. The cpx composition, not opx, as it was assumed, seems to be the main control of the size and composition of spinel concentrations.
DS1990-1289
1990
Ahmed, F.Sadig, A.A., Ahmed, F.Gravity signatures over selected ring complexes in the Sudan, and their tectonic significanceJournal of African Earth Sciences, Vol. 9, No. 3/4, pp. 481-487GlobalGeophysics -gravity, Tectonics
DS2001-0012
2001
Ahmed, M.Ahmed, M., Shivanna, S.Search for kimberlites in the granitic terrain of Gulbarga and Raichur districts, Karnataka.India Geological Survey Records, No. 132, 5, p. 90-91.IndiaNews item - exploration
DS200612-0966
2001
Ahmed, M.Nambiar, A.R., Shivanna, S., Ahmed, M., Srivastava, J.K.Search for kimberlites in Karnataka - status and scope.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 603-613.India, KarnatakaDiamond exploration
DS200912-0004
2009
Ahmed, S.Ahmed, S.Value addition in diamonds and other gemstones by nuclear radiation: the phobias and safety considerations.Atoms for Peace: an Internatiohnal Journal, Interscience Publishers Ltd., August 13, Vol. 2, no. 4, pp. 409-418. Ingenta art00008Technologydiamond
DS201312-0520
2013
Ahmed, S.Kumar, A., Ahmed, S., Priya, R., Sridhar, M.Discovery of lamproites near Vattikod area, nw margin of the Cuddapah basin, eastern Dharwar craton, southern India.Journal of the Geological Society of India, Vol. 82, 4, pp. 307-312.IndiaLamproite
DS201611-2121
2016
Ahmed, S.Kaur, G., Mitchell, R.H., Ahmed, S.Typomorphic mineralogy of the Vattikod lamproites from Mesoproterozoic Ramadugu lamproite field, Nalgonda district, Telangana India: a plausible manifestation of subduction related alkaline magmatism in the Eastern Ghats mobile belt?IGC 35th., 1p. AbstractIndiaLamproite

Abstract: Lamproites are mineralogically complex rocks and their bulk rock geochemistry is not for characterization of their parental magmas (Mitchell and Bergman, [1]). Characterization is best accomplished by consideration of their typomorphic mineralogy. We have investigated nine dykes from Vattikod (VL1:Vl8 and VL10). The mineral assemblage and their compositions are comparable to those of lamproites in terms of the presence of phlogopite (Ti-rich, Al-poor phlogopite and tetraferriphlogopite); amphiboles (potassic-arfvedsonite, potassic-richterite, potassic-ferro-richterite, potassic-katophorite, Ti- rich potassic-katophorite, Ti-rich potassic-magnesio-katophorite); Al-poor pyroxene; feldspars (K- feldspar, Ba-K-feldspar and Na-feldspar), spinels (chromite-magnetite and qandilite-ulvÖspinel-ZnFe2O4). These dykes have also undergone varied degrees of deuteric alteration as shown by the development of secondary phases such as titanite, allanite, hydro-zircon, calcite, chlorite, quartz and cryptocrystalline SiO2. We have classified the Vattikod dyke on the basis of their typomorphic major mineralogy in conjunction with alteration affects as: Group 1 (VL1); Group 2 (VL2 and VL3); Group 3 (VL4 and VL5); Group 4 (VL6, VL7 and VL8); and Group 5 (VL10). Group 2 dykes are pseudoleucite-amphibole-lamproite; Group 3 dykes are pseudoleucite-phlogopite-lamproite; Group 4 dykes are pseudoleucite-phlogopite- amphibole-lamproite. The Group 1 dyke is completely altered and the precursor mineralogy cannot be identified. Group 5 dyke is also extensively altered but contains fresh euhedral apatite microphenocrysts together with pseudomorphs after leucite and is classified as a pseudoleucite-apatite-(phlogopite?) lamproite. It is suggested that the Vattikod lamproites represent a spectrum of modal variants of lamproite produced by the differentiation and crystallization of a common parental peralkaline potassic magma. The near-linear disposition of Deformed Alkaline Rocks and Carbonatites commonly known as DARC’s (Burke and Khan, [2]) and lamproites in eastern India implies a relationship with subduction-related processes (Das Sharma & Ramesh, [3]; Gurmeet Kaur & Mitchell, [4]). We propose that the Vattikod and other lamproites in eastern India emplaced at 1100-1450 Ma are possible manifestations of subduction- related alkaline magmatism along the Eastern Ghats Mobile Belt, in contrast to extension-related anorogenic lamproite magmatism related to supercontinent(s) break-up as has been suggested for Ramadugu and other Dharwar Craton lamproites.
DS201805-0954
2018
Ahmed, S.Kaur, G., Mitchell, R.H., Ahmed, S.Mineralogy of the Vattikod lamproite dykes, Ramadugu lamproite field, Nalgonda District, Telangama: a possible expression of ancient subduction related alkaline magmatism along eastern Ghats mobile belt, India.Mineralogical Magazine, Vol. 82, 1, pp. 35-58.Indialamproite

Abstract: The mineralogy of nine recently discovered dykes (VL1:VL8 and VL10) in the vicinity of Vattikod village, Nalgonda district in Telangana State is described. The mineral assemblage present and their compositions are comparable to those of bona fide lamproites in terms of the presence of phlogopite (Ti-rich, Al-poor phlogopite and tetraferriphlogopite); amphiboles (potassic-arfvedsonite, potassic-richterite, potassic-ferro-richterite, potassic-katophorite, Ti-rich potassic-katophorite, Ti-rich potassic-magnesio-katophorite); Al-poor clinopyroxenes; feldspars (K-feldspar, Ba-K-feldspar and Na-feldspar) and spinels (chromite-magnetite and qandilite-ulvöspinel-franklinite). These dykes have undergone diverse and significant degrees of deuteric alteration as shown by the formation of secondary phases such as: titanite, allanite, hydro-zircon, calcite, chlorite, quartz and cryptocrystalline SiO2. On the basis of their respective mineralogy: the VL4 and VL5 dykes are classified as pseudoleucite-phlogopite lamproite; VL2 and VL3 dykes as pseudoleucite-amphibole-lamproite; and VL6, VL7 and VL8 as pseudoleucite-phlogopite-amphibole-lamproite. VL10 is extensively altered but contains fresh euhedral apatite microphenocrysts together with pseudomorphs after leucite and is classified as a pseudoleucite-apatite-(phlogopite?) lamproite. The mineralogy of the Vattikod lamproite dykes is compared with that of the Ramadugu, Somavarigudem and Yacharam lamproite dykes which also occur in the Ramadugu lamproite field. The lamproites from the Eastern Dharwar Craton are considered as being possible expressions of ancient subduction-related alkaline magmatism along the Eastern Ghats mobile belt.
DS1991-0005
1991
Ahmed, Z.Ahmed, Z., McCormick, G.R.A newly discovered kimberlitic rock from PakistanMineralogical Magazine, Vol. 54, December pp. 537-546PakistanKimberlite, Mineral chemistry
DS1996-0011
1996
Ahmed Benan, C.Ahmed Benan, C., Deynoux, M.Facies association and sequence stratigraphy on an upper Proterozoic cratonic platform: Aldar ..C.r. Academy Of Science, Vol. 322, iia, pp. 625-32.GlobalCraton, Stratigraphy
DS1995-0012
1995
Ahmed Zid, I.Ahmed Zid, I.A kimberlitic lamprophyre and associated alkalic basaltic rocks from Pishlin District, Pakistan.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 4.PakistanSpangar Garkai, Kozh Kach areas, Alkaline rocks
DS1995-0013
1995
Ahmed Zid, I.Ahmed Zid, I., Madon, M.Electron microscopy of high pressure phases synthesized from natural garnets in a diamond anvil cell: mantle.Earth and Planetary Science Letters, Vol. 129, No. 1-4, January pp. 233-248.MantleGarnet mineralogy, Petrology -experimental
DS2002-0012
2002
Ahmedov, A.Ahmedov, A., Panova, E., Krupenik, V., Svehnikova, K.Diamond from Early Proterozoic and Devonian rocks of the joint zone of the Baltic Shield and Russian platform.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.272.Russia, Baltic ShieldLithogenesis - sedimentary basins
DS2003-0248
2003
AhnChen, J.F., Xie, Z., Li, H.M., Zhang, X.D., Zhou, T.X., Park, Ahn, Chen, ZhangU Pb zircon ages for a collision related K rich complex at Shidao in the Sulu ultrahighGeochemical Journal, Vol. 37, pp. 35-46.ChinaBlank
DS200412-0319
2003
AhnChen, J.F., Xie, Z., Li, H.M., Zhang, X.D., Zhou, T.X., Park, Ahn, Chen, ZhangU Pb zircon ages for a collision related K rich complex at Shidao in the Sulu ultrahigh pressure terrane, China.Geochemical Journal, Vol. 37, pp. 35-46.ChinaUHP, shoshonites
DS1950-0139
1953
Ahrens, L.H.Holyk, W., Ahrens, L.H.Potassium in Ultramafic RocksGeochim Et Cosmochim. Acta., Vol. 4, PP. 241-250.South AfricaPetrology
DS1960-0675
1966
Ahrens, L.H.Gurney, J.J., Berg, G.W., Ahrens, L.H.Observations on Caesium Enrichment and the Potassium Rubidium Caesium Relationship in Eclogites from the Roberts Victormine.Nature., Vol. 210, PP. 1025-1027.South AfricaGeochronology, Mineralogy
DS1960-0773
1967
Ahrens, L.H.Ahrens, L.H., Cherry, R.D., Erlank, A.J.Observations on the Th-u Relationship in Zircons from Granitic Rocks and from Kimberlites.Geochim. Et. Cosmochim. Acta., Vol. 31, PP. 2379-2387.South AfricaUranium, Thorium, Mineral Chemistry
DS1970-0699
1973
Ahrens, L.H.Gurney, J.J., Ahrens, L.H.The Zinc Content of Some Ultramafic and Basic RocksGeological Society of South Africa Transactions, Vol. 76, No. 3, PP. 301-307.South AfricaMineralogy
DS1975-0002
1975
Ahrens, L.H.Ahrens, L.H., Dawson, J.B., Duncan, A.R., Erlank, A.J.First International Conference on Kimberlites Held in Cape Town from 24th to 28th September 1973.Physics And Chemistry of The Earth, New York: Pergamon Press, Vol. 9, 936P.GlobalKimberlite, Kimberley, Janlib
DS1975-1169
1979
Ahrens, L.H.Nyambok, I.O., Ahrens, L.H.Geochemistry of the Carbonatite Complexes in East AfricaPhysics and Chemistry of the Earth., Vol. 11, PP. 533-539.East Africa, UgandaLeucitite, Leucite, Genesis, Related Rocks
DS1983-0003
1983
Ahrens, L.H.Ahrens, L.H.New Minerals from the Upper MantleGeological Society of South Africa Quarterly NEWS Bulletin., Vol. 27, No. 3, SEPTEMBER PP. 13-14.South Africa, Kimberley AreaMineralogy
DS1983-0361
1983
Ahrens, T.J.Kondo, K., Ahrens, T.J.Shock Impression of Diamond CrystalGeophysical Research Letters, Vol. 10, No. 4, PP. 181-184.GlobalGenesis, Formation
DS1989-0012
1989
Ahrens, T.J.Ahrens, T.J.Water storage in the mantleNature, Vol. 342, November 9, pp. 122-123GlobalMantle, Genesis, Origin
DS1990-0907
1990
Ahrens, T.J.Lay, T., Ahrens, T.J., Olson, P., Smyth, J., Loper, D.Studies of the earth's deep interior: goals and trendsPhysics Today, Vol. 43, No. 10, October pp. 44-52GlobalDynamic earth system, Mantle
DS1997-0514
1997
Ahrens, T.J.Holland, K.G., Ahrens, T.J.Melting of (magnesium, iron)(magnesium, iron)2 SiO4 at the core-mantle boundary of the earth.Science, Vol. 275, No. 5306, Mar. 14, pp. 1623-25.MantleMelting, Core-mantle boundary
DS2002-0972
2002
Ahrens, T.J.Luo, S.N., Mosenfelder, J.L., Asimow, P.D., Ahrens, T.J.Direct shock wave loading of stishovite to 235 GPa: implications for perovskite stabilityGeophysical Research Letters, Vol. 29, 14, July 15, p. 36-MantleMineralogy
DS200412-0012
2004
Ahrens, T.J.Akins, J.A., Luo, S.N., Asimow, P.D., Ahrens, T.J.Shock induced melting of MgSiO3 perovskite and implications for melts in Earth's lowermost mantle.Geophysical Research Letters, Vol. 31, 14, DOI 10.1029/2004 GLO20237MantleMelt
DS200412-0068
2004
Ahrens, T.J.Asimow, P.D., Sun, D., Akins, J.A., Luo, S.N., Ahrens, T.J.Petrology of the lowermost mantle.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A561.MantleGeophysics - seismics
DS200912-0519
2009
Ahrens, T.J.Mosenfelder, J.L., Asimow, P.D., Frost, D.J., Rubie, D.C., Ahrens, T.J.The MgSiO3 system at high pressure: thermodynamic properties of perovskite, postperovskite and melt from global inversion of shock and static compression data.Journal of Geophysical Research, Vol. 114, B1 B01203.MantlePerovskite
DS1975-0440
1977
Ahuja, H.S.Ahuja, H.S.Kimberlites: a ReviewMsc. Thesis, Northeastern Illinois University, Chicago, GlobalKimberlite, Genesis, Occurrences, Classification
DS2003-0097
2003
Ahuja, k R.Belonoshko, A.B., Ahuja,k R., Johannson, B.Stability of the body centered cubic phase of iron in the Earth's inner coreNature, No. 6952, August 28, pp. 1032-4.MantleGeochemistry
DS200412-0132
2003
Ahuja, k R.Belonoshko, A.B., Ahuja,k R., Johannson, B.Stability of the body centered cubic phase of iron in the Earth's inner core.Nature, No. 6952, August 28, pp. 1032-4.MantleGeochemistry
DS200512-1002
2005
Ahuja, R.Skorodumova, N.V., Belonoshko, A.B., Huang, L., Ahuja, R., Johansson, B.Stability of the MgCO3 structures under lower mantle conditions.American Mineralogist, Vol.90, pp. 1008-1011.MantleCarbon, Liquid outer core, boundary
DS200612-1485
2006
Ahuja, R.Vitos, L., Magyati-Kope, B., Ahuja, R., Kollar, J., Grimvall, G., Johansson, B.Phase transformations between garnet and perovskite phases in the Earth's mantle: a theoretical study.Physics of the Earth and Planetary Interiors, Vol. 156, 1-2, pp. 108-116.MantleLower mantle, majorite, geophysics -seismic
DS200712-0468
2007
Ahuja, R.Isaev, E.I., Skorodumova, N.V., Ahuja, R., Vekilov, Y.K., Johansson, B.Dynamical stability of Fe-H in the Earth's mantle and core regions.Proceedings of National Academy of Sciences USA, Vol. 104, 22, pp. 9168-9177. IngentaMantleChemistry
DS200812-0337
2008
Ahuja, R.Fang, C., Ahuja, R.Local structure and electronic spin transition of Fe bearing MgSiO3 perovskite under conditions of the Earth's lower mantle.Physics of the Earth and Planetary Interiors., Vol. 166, 1-2, pp. 77-82.MantleMineral chemistry
DS201312-1008
2013
AiZeng, X-Q., Zheng, Y-L., Yang, Z-J., Ai, Hu, Q.Study on the micro-FTIR and raman spectra of the alluvial diamonds from Yangtze craton and their geological significance.Spectroscopy and Spectral Analysis, Vol. 33, no. 10.pp. 2694-2699.ChinaAlluvials
DS200512-0664
2005
Ai, X.Ma, C., She, Z., Ai, X.An Early Cretaceous intrusive complex in the Dabie Shan ultrahigh pressure metamorphic terrane, East China. Evidence for the beginning of post orogenic collapse.GAC Annual Meeting Halifax May 15-19, Abstract 1p.ChinaUHP, crustal root
DS2003-0003
2003
Ai, Y.Ai, Y., Zheng, T.The upper mantle discontinuity structure beneath eastern ChinaGeophysical Research Letters, Vol. 30, 21, 2089 DOI.1029/2003GLO17678eastern ChinaGeophysics - seismics
DS2003-0004
2003
Ai, Y.Ai, Y., Zheng, T., Xu, W., He, Y., Dong, D.A complex 660 km discontinuity beneath northeast ChinaEarth and Planetary Science Letters, Vol. 212, 1-2, pp. 63-71.ChinaTectonics
DS200412-0008
2003
Ai, Y.Ai, Y., Zheng, T.The upper mantle discontinuity structure beneath eastern China.Geophysical Research Letters, Vol. 30, 21, Nov. 1, 10.1029/2003 GLO17678ChinaGeophysics - seismics
DS200412-0009
2003
Ai, Y.Ai, Y., Zheng, T., Xu, W., He, Y., Dong, D.A complex 660 km discontinuity beneath northeast China.Earth and Planetary Science Letters, Vol. 212, 1-2, pp. 63-71.ChinaGeophysics - seismics Tectonics
DS200512-1244
2005
Ai, Y.Zhang, L., Song, S., Liou, J.G., Ai, Y., Li, X.Relict coesite exsolution omphacite from western Tian Shan eclogites, China.American Mineralogist, Vol. 90, 1, Jan. pp. 181-186.ChinaUHP
DS200712-0005
2007
Ai, Y.Ai,Y., Chen, Q-F., Zeng, F., Hong, X., Ye, W.The crust and upper mantle structure beneath southeastern China.Earth and Planetary Science Letters, Vol. 260, 3-4, pp. 549-563.ChinaTectonics
DS201212-0827
2012
Ai, Y.Zheng, T., Zhu, R., Liang, Ai, Y.Intralithospheric mantle structures recorded continental subduction.Journal of Geophysical Research, Vol. 117, B3, B03308MantleSubduction
DS201508-0370
2015
Ai, Y.O'Leary, M.C., Lange, R.A., Ai, Y.The compressability of CaCO3-Li2CO3-Na2CO3-K2CO3 liquids: application to natrocarbonatite and CO2- bearing nephelinite liquids from Oldoinyo Lengai.Contributions to Mineralogy and Petrology, Vol. 170, 18p.Africa, TanzaniaDeposit - Oldoinyo Lengai
DS201810-2304
2018
Aibai, A.Cheng, Z., Zhang, Z., Aibai, A., Kong, W., Holtz, F.The role of magmatic and post-magmatic hydrothermal processes on rare earth element mineralization: a study of the Bachu carbonatites from the Tarim Large Igneous Province, NW China.Lithos, Vol. 314-315, pp. 71-87.Chinacarbonatite

Abstract: The contribution of magmatic and hydrothermal processes to rare earth element (REE) mineralization of carbonatites remains an area of considerable interest. With the aim of better understanding REE mineralization mechanisms, we conducted a detailed study on the petrology, mineralogy and C-O isotopes of the Bachu carbonatites, NW China. The Bachu carbonatites are composed predominantly of magnesiocarbonatite with minor calciocarbonatite. The two types of carbonatite have primarily holocrystalline textures dominated by dolomite and calcite, respectively. Monazite-(Ce) and bastnäsite-(Ce), the major REE minerals, occur as euhedral grains and interstitial phases in the carbonatites. Melt inclusions in the dolomite partially rehomogenize at temperatures above 800?°C, and those in apatite have homogenization temperatures (Th) ranging from 645 to 785?°C. Oxygen isotope ratios of the calciocarbonatite intrusions (?18OV-SMOW?=?6.4‰ to 8.3‰), similar to the magnesiocarbonatites, indicate the parental magma is mantle-derived, and that they may derive from a more evolved stage of carbonatite fractionation. The magnesiocarbonatites are slightly enriched in LREE whereas calciocarbonatites have higher HREE concentrations. Both dolomite and calcite have low total REE (TREE) contents ranging from 112 to 436?ppm and 88 to 336?ppm, respectively, much lower than the bulk rock composition of the carbonatites (371 to 36,965?ppm). Hence, the fractional crystallization of carbonates is expected to elevate REE concentrations in the residual magma. Rocks from the Bachu deposit with the highest TREE concentration (up to 20?wt%) occur as small size (2?mm to 3 cm) red rare earth-rich veins (RRV) with barite + celestine + fluorapatite + monazite-(Ce) associations. These rocks are interpreted to have a hydrothermal origin, confirmed by the fluid inclusions in barite with Th in the range 198-267?°C. Hydrothermal processes may also explain the existence of interstitial textures in the carbonatites with similar mineral assemblages. The C-O isotopic compositions of the RRV (?13CV-PDB?=??3.6 to ?4.3‰, ?18OV-SMOW?=?7.6 to 9.8‰) are consistent with an origin resulting from fluid exsolution at the end of the high temperature fractionation trend. A two-stage model involving fractional crystallization and hydrothermal fluids is proposed for the mineralization of the Bachu REE deposit.
DS2002-0939
2002
AibingLi, Aibing, Fischer, K.M., Van der Lee, S., Wysession, M.Crust and upper mantle discontinuity structure beneath eastern North AmericaJournal of Geophysical Research, Vol.107,5, May 28, 10.1029/2002JB001891AppalachiaCore - mantle boundary, Geophysics - seismics
DS1950-0443
1959
Aicard, P.Aicard, P.Application des Methodes Geochimiques (chromium et Nickel) a la Recherche de Pipes Kimberlitique: Relutats Obtenus sur un Pipe Deja Connu (kenieba) Soudan Francais.Annual Mines, PARIS, No. 2, PP. 1-3=106.West Africa, French Equatorial AfricaSekonomata, Geochemistry
DS2002-0931
2002
Aifa, T.Lefort, J.P., Aifa, T.Evidence for circum terrestrial loop of the Apwp of the west African Craton between 2.2 ad 0.9 Ga: its temporary amalgamation to Columbia and Rodinia.11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 32.Africa, Gondwana, RodiniaGeochronology, Reguibat Uplift
DS200412-1109
2004
Aifa, T.LeFort, J.P., Aifa, T., Bourrouilh, R.Paleomagnetic and paleontologic evidence for an antipodal position of the West African Craton and of norther Chin a in Rodinia puComptes Rendus Geoscience, Vol. 336, 2, Feb. pp. 159-165.ChinaGeophysics - magnetism
DS202110-1598
2021
Aifa, T.Aifa, T.Mineralization and sustainable development in the west African craton: from field observations to modelling. ** not specific to diamondsGeological Society of London Special Publication, SP502, 353p. ISBN 9781786204899 July publ. approx lbs 81.00 cost Africacraton

Abstract: This volume combines the results obtained by interdisciplinary groups working on Paleoproterozoic Formations to decipher the origins of the main natural resources through mineralizations and their impacts on the African Economic development. Structural, geophysical, sedimentological, stratigraphical, geochemical, petrophysical and mineralogical analyses are used to highlight the complex mineralizations emplacement and their origin and evolution within the West African Craton.
DS1984-0450
1984
Aikem, C.L.V.Leonhardt, F.H., Aikem, C.L.V.Gravity Study of Some Shallow and Deep Structures in the Ouachita Tectonic Belt, Oklahoma.Geophysics, Vol. 49, No. 5, MAY P. 618. (abstract.).OklahomaMid-continent
DS200512-0434
2005
Aiken, C.Hinze, W.J., Aiken, C., Brozena, J., Coakley, Dater, Flanagan, Forsberg, Hildenbrand, Keller, KelloggNew standards for reducing gravity data: the North American gravity database.Geophysics, Vol. 70, 4, pp. J25-J32.Canada, United StatesGeophysics - gravity
DS1982-0320
1982
Aiken, C.L.V.Keller, G.R., Kruger, J.M., Schneider, R.V., Aiken, C.L.V., Lai.Regional Geophysical Studies of the Southern Oklahoma Aulocogen and Ouachita SystemGeological Society of America (GSA), Vol. 14, No. 3, P. 115, (abstract.).OklahomaMid-continent, Geophysics
DS1983-0349
1983
Aiken, C.L.V.Keller, G.R., Coultrip, R.L., Peeples, W.J., Aiken, C.L.V.A Regional Gravity Study of the Colorado Plateau and Adjacent Regions.Geological Society of America (GSA), Vol. 15, No. 5, P. 317. (abstract.).Colorado, Rocky Mountains, Colorado Plateau, Arizona, New MexicoMid-continent
DS1991-0006
1991
Aiken, J.D.Aiken, J.D.Two late Proterozoic glaciations, Mackenzie Mountains, northwesternCanadaGeology, Vol. 19, No. 5, May pp. 445-448Northwest TerritoriesGeomorphology, Glaciation
DS201606-1078
2016
Aileres, L.Betts, P.G., Armit, R.J., Stewart, J., Aitken, A.R.A., Aileres, L., Donchak, P., Hutton, L., Withnall, I., Giles, D.Australia and Nuna.Geological Society of London Special Publication Supercontinent Cycles through Earth History., Vol. 424, pp. 47-81.AustraliaSupercontinents

Abstract: The Australian continent records c. 1860-1800 Ma orogenesis associated with rapid accretion of several ribbon micro-continents along the southern and eastern margins of the proto-North Australian Craton during Nuna assembly. The boundaries of these accreted micro-continents are imaged in crustal-scale seismic reflection data, and regional gravity and aeromagnetic datasets. Continental growth (c. 1860-1850 Ma) along the southern margin of the proto-North Australian Craton is recorded by the accretion of a micro-continent that included the Aileron Terrane (northern Arunta Inlier) and the Gawler Craton. Eastward growth of the North Australian Craton occurred during the accretion of the Numil Terrane and the Abingdon Seismic Province, which forms part of a broader zone of collision between the northwestern margins of Laurentia and the proto-North Australian Craton. The Tickalara Arc initially accreted with the Kimberley Craton at c. 1850 Ma and together these collided with the proto-North Australian Craton at c. 1820 Ma. Collision between the West Australian Craton and the proto-North Australian Craton at c. 1790-1760 Ma terminated the rapid growth of the Australian continent.
DS200912-0591
2009
Ailleres, L.Porritt, L.A., Cas, R.A., Ailleres, L., Oshust, P.The influence of volcanological and sedimentalogical processes on diamond distribution: example from the Ekati diamond mine, NWT Canada.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyCanada, Northwest TerritoriesDeposit - Ekati
DS201212-0567
2012
Ailleres, L.Porritt, L.A., Cas, R.A.F., Ailleres, L., Oshust, P.The influence of volcanological and sedimentaological processes on diamond grade distribution in kimberlites: examples from the Ekati diamond mine, NWT, Canada.Bulletin of Volcanology, Vol. 73, 8, pp. 1085-1105.Canada, Northwest TerritoriesDiamond grade
DS201412-0056
2014
Ailleres, L.Blaikie, T.N., Ailleres, L., Betts, P.G., Cas, R.A.F.A geophysical comparison of the diatremes of simple and complex maar volcanoes, Newer Volcanics Province, south-eastern Australia.Journal of Volcanology and Geothermal Research, Vol. 276, pp. 64-81.AustraliaVolcanoes
DS201412-0057
2014
Ailleres, L.Blaikie, T.N., Ailleres, L., Betts, P.G., Cas, R.A.F.A geophysical comparison of the diatremes of simple and complex Maar volcanoes, Newer Volcanic Province, south-eastern Australia.Journal of Volcanology and Geothermal Research, Vol. 276, pp. 64-81.AustraliaGeophysics - volcanoes
DS201504-0185
2015
Ailleres, L.Block, S., Ganne, J., Baratoux, A.Z., Parra-Avila, L.A., Jessell, M., Ailleres, L., Siebenaller, L.Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) Orogeny, NW Ghana, West African craton.Journal of Metamorphic Geology, Vol. 33, 5, pp. 463-494.Africa, GhanaGeochronology

Abstract: New petrological and geochronological data are presented on high-grade ortho- and paragneisses from northwestern Ghana, forming part of the Paleoproterozoic (2.25-2.00 Ga) West African Craton. The study area is located in the interference zone between N-S and NE--SW-trending craton-scale shear zones, formed during the Eburnean orogeny (2.15-2.00 Ga). High-grade metamorphic domains are separated from low-grade greenstone belts by high-strain zones, including early thrusts, extensional detachments and late-stage strike-slip shear zones. Paragneisses sporadically preserve high-pressure, low-temperature (HP-LT) relicts, formed at the transition between the blueschist facies and the epidote-amphibolite sub-facies (10.0-14.0 kbar, 520-600 °C), and represent a low (~15 °C km?1) apparent geothermal gradient. Migmatites record metamorphic conditions at the amphibolite-granulite facies transition. They reveal a clockwise pressure-temperature-time (P-T-t) path characterized by melting at pressures over 10.0 kbar, followed by decompression and heating to peak temperatures of 750 °C at 5.0-8.0 kbar, which fit a 30 °C km?1 apparent geotherm. A regional amphibolite facies metamorphic overprint is recorded by rocks that followed a clockwise P-T-t path, characterized by peak metamorphic conditions of 7.0-10.0 kbar at 550-680 °C, which match a 20-25 °C km?1 apparent geotherm. These P-T conditions were reached after prograde burial and heating for some rock units, and after decompression and heating for others. The timing of anatexis and of the amphibolite facies metamorphic overprint is constrained by in-situ U-Pb dating of monazite crystallization at 2138 ± 7 and 2130 ± 7 Ma respectively. The new data set challenges the interpretation that metamorphic breaks in the West African Craton are due to diachronous Birimian ‘basins’ overlying a gneissic basement. It suggests that the lower crust was exhumed along reverse, normal and transcurrent shear zones and juxtaposed against shallow crustal slices during the Eburnean orogeny. The craton in NW Ghana is made of distinct fragments with contrasting tectono-metamorphic histories. The range of metamorphic conditions and the sharp lateral metamorphic gradients are inconsistent with ‘hot orogeny’ models proposed for many Precambrian provinces. These findings shed new light on the geodynamic setting of craton assembly and stabilization in the Paleoproterozoic. It is suggested that the metamorphic record of the West African Craton is characteristic of Paleoproterozoic plate tectonics and illustrates a transition between Archean and Phanerozoic orogens.
DS1991-0007
1991
Aina, A.Aina, A., Emofurieta, W.O.VLF anomalies at contacts between Precambrian rocks in southwest NigeriaGeoexploration, Vol. 28, No. 1, April, pp. 55-66NigeriaGeophysics -VLF., Precambrian
DS1991-0008
1991
Aina, A.Aina, A., Emofurieta, W.O.The use of very low frequency electromagnetic method for non-conductive resource evaluation and geological mappingJournal of African Earth Sciences, Vol. 12, No. 4, pp. 609-616NigeriaGeophysics, Electromagnetics -mapping
DS1992-0010
1992
Aina, A.Aina, A., Olarewaju, V.O.Geological interpretation of aeromagnetic dat a in some parts of North central NigeriaJournal of Africam Earth Sciences, Vol. 14, No. 1, pp. 103-109NigeriaGeophysics, Granite ring complexes
DS2003-1038
2003
Ainbinder, H.Ovcharenko, O.V., Ainbinder, H., Shilin, K.Y., Kramskov, N.P.Geomechanical substantiation of the parameters for underground mining of MirJournal of Mining Science, ( Kluwer Academic), Vol. 38, 6, pp. 528-33.Russia, Siberia, YakutiaMining, Deposit - Mir
DS200412-1485
2003
Ainbinder, H.Ovcharenko, O.V., Ainbinder, H., Shilin, K.Y., Kramskov, N.P.Geomechanical substantiation of the parameters for underground mining of Mir kimberlite pipe.Journal of Mining Science, Vol. 38, 6, pp. 528-33.Russia, Siberia, YakutiaMining Deposit - Mir
DS201012-0800
2009
Ainbinder, L.L.Trubetskoy, K.N., Galchenko, Y.P., Ainbinder, L.L., Sabinyan, G.V.Outlook for the enhanced safety and improved efficiency of diamond deposit mining.Journal of Mining Science, Vol. 45, 6, pp. 581-590.RussiaMining - Yakutia pipes
DS1989-0013
1989
Ainemer, A.I.Ainemer, A.I.Placer forming barriersMarine Mining, Vol. 8, pp. 281-291GlobalPlacers, Classifications
DS1989-0014
1989
Ainemer, A.I.Ainemer, A.I.Placer forming barriersMarine Mining, Vol. 8, pp. 283-91.GlobalPlacers, alluvials, Geomorphology - not specific to diamonds - mentions
DS1984-0003
1984
Aines, R.Aines, R., Rossman, G.R.Water Content of Mantle GarnetsGeology, Vol. 12, Dec. pp. 720-23.Colorado PlateauGarnet Megacrysts, Green Knobs, Garnet Ridge
DS1982-0002
1982
Aines, R.D.Aines, R.D., Rossman, G.R.The Hydrous Component in GarnetsGeological Society of America (GSA), Vol. 14, No. 7, P. 430, (abstract.).Colorado Plateau, South Africa, United States, Rocky MountainsMineralogy
DS200412-1817
2003
Aiqun, S.Shuyin, N., Quanlin, H., Zengqian, H., Aiqun, S., Baode, W., Hongyang, L., Chuanshi, X.Cascaded evolution of mantle plumes and metallogenesis of core and mantle derived elements.Acta Geologica Sinica, Vol. 77, 4, pp. 522-536.MantleMetallogeny
DS1988-0681
1988
Aires, J.R.Szatmari, P., Aires, J.R.Physical modelling of early Cretaceous continental breakup between South America and Africa.(in Portugese).Revista Brasileira de Geociencias, (in Portugese)., Vol. 18, No. 3, September p. 313. (abstract.)BrazilTectonics
DS201809-1988
2015
Airo, M.L.Airo, M.L.Geophysical signatures of mineral deposit types ( mentions diamonds).Finland Geological Survey, http://tupa.gtk.fi /julkaisu/ specialpaper/ sp_058.pdfFinlandgeophysics

Abstract: In this Special Paper volume, the review of physical properties of ore deposit types or mineralization styles is mainly based on published information, in particular on the key note speeches and presentations that were given at two geosciences conferences: Exploration07 held in Toronto in 2007 (proceedings by Milkereit (ed.) 2007), and the SGA meeting held in Uppsala in 2013 (proceedings by Johnsson et al. (eds.) 2013). Diamonds referred to on p. 13.
DS200812-0334
2008
AitAyad, N.Ezzouhari, H., Ribeiro, M.L., AitAyad, N., Moreira, M.E., Charif, A., Ramos, J.M.F., De Oliveira, D.P.S., Coke, C.The magmatic evolution at the Moroccan outboard of the West African Craton between the Late Neoproterozoic and the Early Palaeozoic.Special Publication - Geological Society of London, No. 297, pp. 329-344.Africa, MoroccoMagmatism
DS1994-0030
1994
Aitcheson, S.J.Aitcheson, S.J., Forrest, A.H.Quantification of crustal contamination in open magmatic systemsJournal of Petrology, Vol. 35, No. 2, April pp. 461-488GlobalMagmatism, Crustal contamination
DS1995-0014
1995
Aitcheson, S.J.Aitcheson, S.J., et al.lead isotopes define basement domains of the Altiplano central AndesGeology, Vol. 23, No. 6, June pp. 555-8.Argentina, Peru, Bolivia, ChileGeophysics - gravity
DS1995-0015
1995
Aitcheson, S.J.Aitcheson, S.J., Harmon, R.S., et al.lead isotopes define basement domains of the Altiplano central AndesGeology, Vol. 23, No. 6, June pp. 555-558Peru, Chile, Argentina, AndesGeochronology, Altiplano -Puna Plateau
DS1995-0016
1995
Aitchison, J.C.Aitchison, J.C., Flood, P.G.Gamilaroi Terrane: a Devonian rifted intra-oceanic island arc assemblage, New South Wales Australiavolcanism Assoc. Extensional...Geological Society of London Sp, No. 81, pp. 155-168AustraliaNew England Orogen, Tectonics
DS1997-0195
1997
Aitchison, J.C.Clarke, G.L., Aitchison, J.C., Cluzel, D.Eclogites and blueschists of the Pam Peninsula, northeast New Caledonia: areappraisalJournal of Petrology, Vol. 38, No. 7, July pp. 843-876New CaledoniaMagma
DS200412-1212
2004
Aitchison, J.C.Malpas, J., Fletcher, C.J.N., Aitchison, J.C.Aspects of the tectonic evolution of China.Geological Society of London Special Paper, No. 226, 368p. $140.ChinaBook - tectonics
DS200512-0011
2005
Aitchison, J.C.Ali, J.R., Aitchison, J.C.Greater India. 80 year old concept in plate tectonic models of India-Asia collision system.Earth Science Reviews, Vol. 72, 3-4, pp. 169-188.IndiaTectonics, Gondwana, paleogeography
DS200512-0680
2004
Aitchison, J.C.Malpas, J., Fletcher, C.J.N., Ali, J.R., Aitchison, J.C.Aspects of the tectonic evolution of China.Geological Society of London , Special Publication 226, 368p. $134.ChinaBook - tectonics
DS200612-0013
2005
Aitchison, J.C.Ali, J.R., Aitchison, J.C.Greater India.Earth Science Reviews, Vol. 72, 3-4, pp. 169-188.IndiaTectonics
DS200912-0106
2009
Aitchison, J.C.Chan, G.H.N., Waters, D.J., Searle, M.P., Aitchison, J.C., Horstwood, M.S.A., Crowley, Q., Lo, C.H., Chan J.Probing the basement of southern Tibet: evidence from crustal xenoliths entrained in a Miocene ultrapotassic dyke.Journal of the Geological Society, Vol. 166, 1, pp. 45-52.Asia, TibetAlkalic
DS201112-0086
2011
Aitken, A.Betts, P.G., Giles, D., Aitken, A.Paleoproterozoic accretion processes of Australia and comparisons with Laurentia.International Geology Review, Vol. 53, no. 11-12, pp. 1357-1376.Australia, CanadaTectonics
DS201610-1884
2016
Aitken, A.Lindsay, M., Spratt, J., Occhipinti, S., Aitken, A., Dentith, M., Metelka, V., Hollis, J., Tyler, I.Integrated interpretation of magnetotelluric and potential field data: assessing the northeast Kimberley region. ( no mention of kimberlites)ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 4p.AustraliaGeophysics
DS200812-0009
2008
Aitken, A.R.A.Aitken, A.R.A., Betts, P.G.High resolution aeromagnetic dat a over central Australia assist Grenville era 1300-11 Ma Rodinia reconstructions.Geophysical Research Letters, Vol. 35, 1, L01306-400.Gondwana, RodiniaGeophysics - magnetics
DS201312-0012
2013
Aitken, A.R.A.Aitken, A.R.A., Raimondo, T., Capitano, F.A.The intraplate character of supercontinent tectonics.Gondwana Research, Vol. 24, 3-4, pp. 807-814.AfricaGeodynamics
DS201606-1078
2016
Aitken, A.R.A.Betts, P.G., Armit, R.J., Stewart, J., Aitken, A.R.A., Aileres, L., Donchak, P., Hutton, L., Withnall, I., Giles, D.Australia and Nuna.Geological Society of London Special Publication Supercontinent Cycles through Earth History., Vol. 424, pp. 47-81.AustraliaSupercontinents

Abstract: The Australian continent records c. 1860-1800 Ma orogenesis associated with rapid accretion of several ribbon micro-continents along the southern and eastern margins of the proto-North Australian Craton during Nuna assembly. The boundaries of these accreted micro-continents are imaged in crustal-scale seismic reflection data, and regional gravity and aeromagnetic datasets. Continental growth (c. 1860-1850 Ma) along the southern margin of the proto-North Australian Craton is recorded by the accretion of a micro-continent that included the Aileron Terrane (northern Arunta Inlier) and the Gawler Craton. Eastward growth of the North Australian Craton occurred during the accretion of the Numil Terrane and the Abingdon Seismic Province, which forms part of a broader zone of collision between the northwestern margins of Laurentia and the proto-North Australian Craton. The Tickalara Arc initially accreted with the Kimberley Craton at c. 1850 Ma and together these collided with the proto-North Australian Craton at c. 1820 Ma. Collision between the West Australian Craton and the proto-North Australian Craton at c. 1790-1760 Ma terminated the rapid growth of the Australian continent.
DS1989-0015
1989
Aitken, J.D.Aitken, J.D.Uppermost Proterozoic Formations in central Mackenzie Mountains, NorthwestTerritoriesGeological Survey of Canada Bulletin, No. 368, 27p. Database # 17639Northwest TerritoriesProterozoic, Geology
DS1993-1543
1993
Aitken, J.D.Stott, D.F., Cook, G.G., Aitken, J.D.Sedimentary cover of the craton: CanadaGeological Society of America DNAG Volume, GNC-D1, 826p. approx. $ 115.00CanadaBook -table of contents, Craton -sedimentary cover
DS1993-1544
1993
Aitken, J.D.Stott, D.F., Cook, G.G., Aitken, J.D.Sedimentary cover of the craton: CanadaGeological Society of America, DNAG Volumes, GNC-D1, 826p. ISBN 0-660-13133-1 $ 115.00 United StatesCanadaWestern Basin, stratigraphy, industrials, Hudson Platform, tectonics
DS1900-0001
1900
Aitton, D.Aitton, D.Eene Bladzijde Uit de Geschiedenis Van den O.v.sDordrecht: Corns. Morks, 14P.Africa, South AfricaHistory
DS200612-0005
2006
Aizawa, Y.Aizawa, Y., Yoneda, A.P V T equation of state of MgSiO3 perovskite and MgO periclase: implications for lower mantle composition.Physics of the Earth and Planetary Interiors, Vol. 155, 1-2, pp. 87-95.MantleGeophysics - seismics, model
DS1988-0324
1988
Ajai KumarJain, Ajai Kumar, Tapi, R.D.Study of carbonatite in the northeast of BarwahDistrict, Khargone, SOURCE[ Vijana Parshad Anusandhan Patrike, (Ind)Vijana Parshad Anusandhan Patrike, (Ind), Vol. 31, No. 2-3, June pp. 89-96IndiaCarbonatite
DS1975-1253
1979
Ajakaiye, D.E.Verheijen, P.J.T., Ajakaiye, D.E.Geophysical Anomalies Over a Pipe Suspectedly Kimberlite In the Precambrian Metamorphic Schist Belt of Northern Nigeria.Geoexploration., Vol. 17, PP. 293-303.GlobalKimberlite, Geophysics, Groundmag
DS1987-0549
1987
Ajakaiye, D.E.Onugba, A., Ajakaiye, D.E.Resistivity and seismic refraction survey of the Masari-KafurKimberlite pipe in NigeriaExploration 87, Technical abstract volume, held Toronto, Sept. 27-Oct., p. 52 abstract onlyNigeriaGeophysics
DS1989-1153
1989
Ajakaiye, D.E.Onugba, A., Bello, A., Ajakaiye, D.E.Resistivity and seismic refraction survey of the Masari/Kafur Kimberlite pipe in northern Nigeria ( and its groundwater reserves)Journal of African Earth Sciences, Vol. 9, No. 2, pp. 235-243NigeriaGeophysics, Seismics
DS1986-0391
1986
Ajarzo, J.MAjarzo, J.MThe argyle diamond mine (1986)The Syrian Journal of Geology, Vol. 11-12, pp. 17-22AustraliaBlank
DS1996-0072
1996
Ajayan, P.M.Banhart, T., Ajayan, P.M.Carbon onion as nanoscopic pressure cells for diamond formationNature, Vol. 382, No. 6590, Aug. 1, pp. 433-435.GlobalDiamond genesis, Diamond morphology
DS2003-0005
2003
Ajit, T.Ajit, T., Reddy, K., Sridhar, M., Ravi, S., Charavrthi, V., Neelakaran, S.Petrography and geochemistry of the Krishna lamproite field, Andhra PradeshJournal of the Geological Society of India, Vol. 61, 2, Feb., pp. 131-46.India, Andhra PradeshLamproite
DS200412-0010
2003
Ajit, T.Ajit, T., Reddy, K., Sridhar, M., Ravi, S., Charavrthi, V., Neelakaran, S.Petrography and geochemistry of the Krishna lamproite field, Andhra Pradesh.Journal of the Geological Society of India, Vol. 61, 2, Feb., pp. 131-46.India, Andhra PradeshGeochemistry Lamproite
DS201112-0649
2011
Aka, F.T.Marzoli, A., Aka, F.T., Chiaradia, M., Reisberg, L., Merle, R.Origin of Cameroon Line basanites from metasomatized lithosphere.Goldschmidt Conference 2011, abstract p.1420.Africa, CameroonCongo craton keel
DS1988-0004
1988
Akagi, T.Akagi, T., Masuda, A.Isotopic and elemental evidence for a relationship between kimberlite and Zaire cubic diamondsNature, Vol. 336, No. 6200, Dec. 15, pp. 665-667Democratic Republic of CongoDiamond morphology
DS1988-0444
1988
Akagi, T.Masuda, A., Akagi, T.The cause of misleading K-Ar ages of diamonds, actually young but apparently older than the solar systemGeochemical Journal, Vol. 22, pp. 139-142GlobalAge determinations, Experimental
DS1990-0105
1990
Akagi, T.Akagi, T.Genesis of diamonds and behaviour of trace elements in seawater.*JPNGeochemistry, *JPN., Vol. 24, No. 1, pp. 1-12GlobalGeochemistry, Diamond genesis
DS2002-0799
2002
Akagi, T.Kagi, H., Sato, S., Kanda, T., Akagi, T.Internal strain and thermal history of carbonado inferred from photoluminescence spectroscopy: relationship to carbon isotopic compositions.Eos, American Geophysical Union, Spring Abstract Volume, Vol.83,19, 1p.Central African RepublicDiamond - morphology, carbonado
DS200712-0502
2007
Akagi, T.Kagi, H., Sato, S., Akagi, T., Kanda, H.Generation history of carbonado inferred from photoluminescence spectra, cathodluminesence imaging, and carbon isotope composition.American Mineralogist, Vol. 91, 1, pp. 217-224.Africa, Central African RepublicCarbonado, radiation damage
DS200812-0010
2008
Akai, C.Akai, C.K richterite olivine phlogopite diopside sanidine lamproites from the Afyon volcanic province, Turkey.Geological Magazine, Vol. 145, 4, pp. 570-585.Europe, TurkeyLamproite
DS200812-0919
2008
Akai, C.Prelevic, D., Boev, B., Zouros, N., Akai, C.Lamproites and alkaline rocks of southern Balkans and Aegean region.9th. IKC Field Trip Guidebook, CD 45p.Europe, Macedonia, Greece, TurkeyGuidebook - lamproites
DS201012-0597
2010
Akai, C.Prelevic, D., Akai, C., Romer, R.L., Foley, S.F.Lamproites as indicators of accretion and/or shallow subduction in the assembly of south western Anatolia, Turkey.Terra Nova, in press available,Europe, TurkeyLamproite
DS1990-0106
1990
Akaishi, M.Akaishi, M., Kanda, H., Yamoka, S.Synthesis of diamond from graphite-carbonate systems under very high temperature and pressureJournal of Crystal Growth, Vol. 104, pp. 578-581GlobalDiamond synthesis, Experimental mineralogy
DS1993-0015
1993
Akaishi, M.Akaishi, M., Kanda, H., Yamaoka, S.Phosphorous: an elemental catalyst for diamond synthesis and growthScience, Vol. 259, No. 5101, March 12, pp. 1592-1593GlobalDiamond synthesis
DS1993-0041
1993
Akaishi, M.Arima, M., Nakayama, K., Akaishi, M., Yamaoka, S., Kanda, H.Crystallization of diamond from a silicate melt of kimberlite composition in high temperature and high pressure experiments.Geology, Vol. 21, No. 11, November pp. 968-970.GlobalDiamond genesis, Experimental petrology
DS2002-0057
2002
Akaishi, M.Arima, M., Kozai, Y., Akaishi, M.Diamond nucleation and growth by reduction of carbonate melts under high pressure and high temperature conditions.Geology, Vol.30,8,Aug.pp.691-4.MantleGenesis - diamond morphology
DS201012-0598
2010
Akal, C.Prelevic, D., Akal, C., Foley, S.F., Romer, R.L., Stracke, A., Van den Bogaard,P.Post collisional mantle dynamics of an orogenic lithosphere: lamproitic mafic rocks from SW Anatolia, Turkey.Geological Society of America Abstracts, 1p.Europe, TurkeyLamproite
DS201112-0824
2011
Akal, C.Prelevic, D., Akal, C., Foley, S.F., Romer, R.R.,Stracke, A., Van den Bogaard, P.Ultrapotassic mafic rocks as geochemical proxies for post collisional dynamics of orogenic lithospheric mantle: the case of southwestern Anatolia, Turkey.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, TurkeyAlkalic
DS201112-0825
2011
Akal, C.Prelevic, D., Akal, C., Romer, R.R., Sracke, A., Van den Bogaard, P.Ultrapotassic mafic rocks as geochemical proxies for post collisional dynamics of orogenic lithospheric mantle: the case of southwestern Anatolia, Turkey.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.119-121.Europe, TurkeyLamproite
DS201112-0826
2011
Akal, C.Prelevic, D., Akal, C., Romer, R.R., Sracke, A., Van den Bogaard, P.Ultrapotassic mafic rocks as geochemical proxies for post collisional dynamics of orogenic lithospheric mantle: the case of southwestern Anatolia, Turkey.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.119-121.Europe, TurkeyLamproite
DS201512-1970
2015
Akam, C.Simandl, G.J., Akam, C., Paradis, S.Selected critical materials: uses, markets, and resources.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov 13-14 2015, pp. 1-4.GlobalStrategic materials
DS201801-0063
2017
Akam, C.Simandl, G.J., Mackay, D.A.R., Ma, X., Luck, P., Gravel, J., Akam, C.The direct indicator mineral concept and QEMSCAN applied to exploration for carbonatite and carbonatite related ore deposits.in: Ferbey, T. Plouffe, A., Hickein, A.S. eds. Indicator minerals in tills and stream sediments of the Canadian Cordillera. Geological Association of Canada Special Paper,, Vol. 50, pp. 175-190.Canada, British Columbiacarbonatite - Aley, Lonnie, Wicheeda

Abstract: This volume consists of a series of papers of importance to indicator minerals in the Canadian Cordillera. Topics include the glacial history of the Cordilleran Ice Sheet, drift prospecting methods, the evolution of survey sampling strategies, new analytical methods, and recent advances in applying indicators minerals to mineral exploration. This volume fills a notable knowledge gap on the use of indicator minerals in the Canadian Cordillera. We hope that the volume serves as a user guide, encouraging the wider application of indicator minerals by the exploration community.
DS201911-2507
2019
Akam, C.Akam, C., Simandl, G.J., Lett, R., Paradis, S., Hoshino, M., Kon, Y., Araoka, D., Green, C., Kodama, S., Takagi, T., Chaudhry, M.Comparison of methods for the geochemical determination of rare earth elements: Rock Canyon Creek REE-F-Ba deposit case study, SE British Columbia, Canada.Geochemistry: Exploration, Environment, Analysis, Vol. 19, pp. 414-430.Canada, British Columbiageochemistry

Abstract: Using Rock Canyon Creek REE-F-Ba deposit as an example, we demonstrate the need for verifying inherited geochemical data. Inherited La, Ce, Nd, and Sm data obtained by pressed pellet XRF, and La and Y data obtained by aqua regia digestion ICP-AES for 300 drill-core samples analysed in 2009 were compared to sample subsets reanalysed using lithium metaborate-tetraborate (LMB) fusion ICP-MS, Na2O2 fusion ICP-MS, and LMB fusion-XRF. We determine that LMB ICP-MS and Na2O2 ICP-MS accurately determined REE concentrations in SY-2 and SY-4, and provided precision within 10%. Fusion-XRF was precise for La and Nd at concentrations exceeding ten times the lower detection limit; however, accuracy was not established because REE concentrations in SY-4 were below the lower detection limit. Analysis of the sample subset revealed substantial discrepancies for Ce concentrations determined by pressed pellet XRF in comparison to other methods due to Ba interference. Samarium, present in lower concentrations than other REE compared, was underestimated by XRF methods relative to ICP-MS methods. This may be due to Sm concentrations approaching the lower detection limits of XRF methods, elemental interference, or inadequate background corrections. Aqua regia dissolution ICP-AES results, reporting for La and Y, are underestimated relative to other methods.
DS1975-0232
1976
Akaogi, M.Aoki, K., Fujino, K., Akaogi, M.Titanochondrite and Titanoclinohumite Derived from the Upper Mantle in the Buell Park Kimberlite, Arizona.Contributions to Mineralogy and Petrology, Vol. 56, PP. 243-253.GlobalKimberlite, Colorado Plateau, Rocky Mountains
DS2000-0542
2000
Akaogi, M.Kubo, A., Akaogi, M.Post garnet transitions in the system up to 28 Gpas: phase relations of garnet, ilmenite and perovskite.Physical Earth and Planetary Interiors, Vol. 121, No. 1-2, pp.85-102.GlobalGarnets, Perovskite
DS2000-0943
2000
Akaogi, M.Suzuki, T., Akaogi, M., Nakamura, E.Partioning of major elements between garnet structured minerals and silicate melt at pressure3-15 GPa.Physical Earth and Planetary Interiors, Vol. 120, No.1-2, pp. 79-92.GlobalPetrology - experimental, Garnet - silicate melts
DS2002-0013
2002
Akaogi, M.Akaogi, M., Tanaka, A., Ito, E.Garnet ilmenite perovskite transitions in the system ... at high pressures and high temperatures: phase equilibria, colorimetry and implications for mantle structurePhysics of the Earth and Planetary Interiors, Vol. 132, 4, pp. 303-24.MantleStructure - UHP
DS200712-0006
2007
Akaogi, M.Akaogi, M.Phase transitions of minerals in the transition zone and upper part of the lower mantle.Ohtani: Advances in high pressure mineralogy, pp. 1-14.MantleMineralogy
DS201212-0333
2012
Akaogi, M.Ishii, T., Kojitani, H., Akaogi, M.High pressure phase transitions and subduction behaviour of continent crust at pressure temperature conditions up to the upper part of the lower mantle.Earth and Planetary Science Letters, Vol. 357-358, pp. 31-41.MantleSubduction
DS201802-0218
2018
Akaogi, M.Akaogi, M., Kawahara, A., Kojitani, H., Yoshida, K., Anegawa, Y., Ishii, T.High pressure phase transitions in MgCr2O4 MgSiO4 composition: reactions between olivine and chromite with implications for ultrahigh pressure chromitites.American Mineralogist, Vol. 103, pp. 161-170.Mantlechromites
DS1985-0002
1985
Akasaka, M.Akasaka, M., Ohashi, H.57 Iron Mossbauer Study of Synthetic Iron 3 MelilitesPhysics Chem. Minerals, Vol. 12, No. 1, PP. 13-18.GlobalExperimental Petrology
DS200612-0628
2005
Akatkin, V.N.Ivanov, V.V., Kolesova, L.G., Khanchuk, A.I., Akatkin, V.N., Molchanova, G.B., Nechaev, V.P.Find of diamond crystals in Jurassic rocks of the Meymechite picrite complex in the Sikhote Alin Orogenic belt.Doklady Earth Sciences, Vol. 404, 7, pp. 975-978.RussiaPicrite
DS1984-0004
1984
Akbari, G.E.Akbari, G.E.The Origin and Evolution of the Earth; S Atmosphere and Hydrosphere.Ph.d. Thesis, University of Georgia (athens), 169P.GlobalExperimental, Fluid Inclusions, Diamonds, Models
DS200612-0194
2005
Akber-Knutson, S.Bukowinski, M.S.T., Akber-Knutson, S.The role of theoretical mineral physics in modeling the Earth's interior.American Geophysical Union, Geophysical Monograph, ed. Van der Hilst, Earth's Deep mantle, structure ...., No. 160, pp. 137-164.MantleGeophysics - seismics
DS200712-1041
2007
Akber-Knutson, S.Steinle-Neumann, G., Lee, K.K.M., Akber-Knutson, S.Potassium partitioning in the lowermost mantle from ab-initio computations.Plates, Plumes, and Paradigms, 1p. abstract p. A971.MantleGeodynamics
DS200412-0011
2003
AKD LimitedAKD LimitedAKD recovers another 244 diamonds at Abaete. Lico target.MiningNews.net, May 16, 1p.South America, BrazilNews item - press release
DS1999-0006
1999
Akelaitis, D.Akelaitis, D.Recent developments for migrating individualsThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Vol. 92, No. 1033, Sept. pp. 109-110.CanadaEconomics - tax
DS1970-0459
1972
Akella, J.Akella, J., Boyd, F.R.Partioning of Titanium and Aluminum Between Pyroxenes, Garnets and OxideCarnegie Institute Yearbook, 1971, PP. 378-384.IndiaMineral Chemistry, Experimental Petrology
DS1970-0460
1972
Akella, J.Akella, J., Boyd, F.R.Partitioning of Titanium and Aluminum between Pyroxenes, Garnets and oxides.Carnegie Institute Yearbook, FOR 1971, PP. 378-384.Lesotho, South AfricaMatsoku, Skaergaard, Research
DS1970-0860
1974
Akella, J.Akella, J.Solubility of Al203 in Orthopyroxene Coexisting with Garnet and Clinopyroxene for Compositions in the Diopside Pyrope Join in the System Casi03 Mgsi03 Al203.Carnegie Institute Yearbook, FOR 1973, PP. 273-277.GlobalMineralogy
DS1970-0861
1974
Akella, J.Akella, J., Boyd, F.R.Petrogenetic Grid for Garnet LherzolitesCargegie Institute Yearbook For 1973, PP. 269-273.South AfricaMineral Chemistry, Petrography
DS1975-0441
1977
Akella, J.Akella, J., Mccallister, R.H., Meyer, H.O.A.Mineralogical Studies on the Diamondiferous Kimberlite of The Wajrakarur Area Southern India #1University of California LAWRENCE LIVERMORE LAB., National Technical Information Service Report No. 7807, 21P.India, Andhra PradeshMineralogy
DS1975-0906
1979
Akella, J.Akella, J., Rao, P.S., Mcallister, R.H., Boyd, F.R., Meyer, H.O.Mineralogical Studies on the Diamondiferous Kimberlite of The Wajrakarur Area, Southern India #2Proceedings of Second International Kimberlite Conference, Vol. 1, PP. 172-177.India, Andhra PradeshMineralogy
DS201810-2305
2018
Akensov, S.M.Chukanov, N.V., Rastsvetaeva, R.K., Kruszewski, L., Akensov, S.M., Rusakov, V., Britvin, S.N., Vozchikova, S.A.Siudaite, Na8(Mn2+2Na) Ca6Fe3+3Zr3NbSi25O74(OH)2Cl.5H20: a new eudialyte group mineral from the Khibiny alkaline massif, Kola Peninsula.Physics and Chemistry of Minerals, Vol. 45, pp. 745-758.Russia, Kola Peninsulaalkaline

Abstract: The new eudialyte-group mineral siudaite, ideally Na8(Mn2+2Na)Ca6Fe3+3Zr3NbSi25O74(OH)2Cl•5H2O, was discovered in a peralkaline pegmatite situated at the Eveslogchorr Mt., Khibiny alkaline massif, Kola Peninsula, Russia. The associated minerals are aegirine, albite, microcline, nepheline, astrophyllite, and loparite-(Ce). Siudaite forms yellow to brownish-yellow equant anhedral grains up to 1.5 cm across. Its lustre is vitreous, and the streak is white. Cleavage is none observed. The Mohs’ hardness is 4½. Density measured by hydrostatic weighing is 2.96(1) g/cm3. Density calculated using the empirical formula is equal to 2.973 g/cm3. Siudaite is nonpleochroic, optically uniaxial, negative, with ??=?1.635(1) and ??=?1.626(1) (??=?589 nm). The IR spectrum is given. The chemical composition of siudaite is (wt%; electron microprobe, H2O determined by HCN analysis): Na2O 8.40, K2O 0.62, CaO 9.81, La2O3 1.03, Ce2O3 1.62, Pr2O3 0.21, Nd2O3 0.29, MnO 6.45, Fe2O3 4.51. TiO2 0.54, ZrO2 11.67, HfO2 0.29, Nb2O5 2.76, SiO2 47.20, Cl 0.54, H2O 3.5, -O?=?Cl ??0.12, total 99.32. According to Mössbauer spectroscopy data, all iron is trivalent. The empirical formula (based on 24.5 Si atoms pfu, in accordance with structural data) is [Na7.57(H2O)1.43]?9(Mn1.11Na0.88Ce0.31La0.20Nd0.05Pr0.04K0.41)?3(H2O)1.8(C a5.46Mn0.54)?6(Fe3+1.76Mn2+1.19)?2.95Nb0.65(T i0.20Si0.50)?0.71(Zr2.95Hf0.04Ti0.01)?3Si24.00Cl0.47O70(OH)2Cl0.47•1.2H2O. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is trigonal, space group R3m, with a?=?14.1885(26) Å, c?=?29.831(7) Å, V?=?5200.8(23) Å3 and Z?=?3. Siudaite is chemically related to georgbarsanovite and is its analogue with Fe3+-dominant M2 site. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.38 (60) (-114), 4.29 (55) (-225), 3.389 (47) (131), 3.191 (63) (-228). 2.963 (100) (4-15), 2.843 (99) (-444), 2.577 (49) (3-39). Siudaite is named after the Polish mineralogist and geochemist Rafa? Siuda (b. 1975).
DS1950-0461
1959
Akers, J.P.Callahan, J.T., Kam, W., Akers, J.P.The Occurrence of Ground Water in Diatremes of the Hopi Buttes Area, Arizona.Plateau, Vol. 32, No. 1, PP. 1-12, JULY.United States, Arizona, Colorado PlateauDiatreme
DS1970-0219
1971
Akers, J.P.Akers, J.P., Shorty, J.C., Stevens, P.R.Hydrogeology of the Cenozoic Igneous Rocks, Navajo and Hopiindian Reservations, Arizona, New Mexico and Utah.United States Geological Survey (USGS) PROF. PAPER., No. 521-D, 17P.United States, Colorado Plateau, Rocky Mountains, Arizona, Utah, New MexicoDiatreme
DS1993-1673
1993
akeyeva, L.I.Vinnik, L.P., Usenko, A.Yu., akeyeva, L.I., Oreshin, S.I.Strain state of the upper mantle under the USSRDoklady Academy of Sciences USSR, Earth Science Section, Vol. 318, No. 1-6, March 1992 Publishing date pp. 56-61.RussiaMantle, Geophysics
DS1993-1145
1993
Akhemedov, M.A.Novgorodova, M.I., Trubkin, N.V., Akhemedov, M.A., Satvaldiev, M.h.Inclusions of natrium fluoride and high alkaline silicate glasses in xenogene diamondgranitoids.(Russian)Proceedings of the Russian Mineralogical Society, (Russian), No. 1, pp. 88-95.RussiaDiamond morphology, Diamond inclusions
DS200412-0740
2003
Akhremkova, G.S.Gubarevich, A.V., Akhremkova, G.S., Lapina, V.A.Properties of the surface of ultrafine diamonds.Russian Journal of Physical Chemistry, Vol. 77, 11, pp. 1832-36. Ingenta 1035296891TechnologyDiamond morphology
DS201212-0512
2012
Akhtar, J.Nayak, S.S., Ravi, S., Patel, S.C., Akhtar, J.Ilmenite macrocrysts in Proterozoic kimberlites from southern India.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractIndiaDeposit - Wajrakarur, Lattavaram, Timmasamudram, Chigicherla
DS1992-0006
1992
Akhvlediani, K.T.Adamia, S., Akhvlediani, K.T., Kilasonia, V.M., Nairn, A.E.M.Geology map of the Dubawnt Lake area, Northwest TerritoriesInternational Geology Review, Vol. 34, No. 5, May pp. 447-476Russia, GeorgiaGeology, Review
DS1982-0003
1982
Akimaa, H.Akimaa, H.Some Examples of Multi Channel Analyses of Land sat and Geophysical DataPhotogrammetric Journal of Finland, Vol. 9, No. 1, pp. 38-47FinlandSokli Carbonatite, Geophysics, Remote Sensing
DS1970-0946
1974
Akimoto, S.Kono, M. , Akimoto, S.Magnetic Properties of KimberliteRock Magnetism And Paleogeophysics, Vol. 2, PP. 2-4.GlobalKimberlite, Geophysics
DS1960-0902
1968
Akimov, A.P.Akimov, A.P., Berzina, I.G.Uranium Contents in Eclogite Inclusions from Kimberlite PipeDoklady Academy of Science USSR, Earth Science Section., Vol. 181, No. 1-6, PP. 208-2L0.RussiaBlank
DS1970-0001
1970
Akimov, A.P.Akimov, A.P.Basification and Assimilation of Plagioclase Gneisses Within Kimberlites.Akad. Nauk Sssr, Izv. Ser. Geol., No. 3, PP. 42-48.RussiaBlank
DS1970-0002
1970
Akimov, A.P.Akimov, A.P., Semenov, G.S.Content of Radioactive Elements in the Kimberlites of the Siberian PlatformDoklady Academy of Science USSR, Earth Science Section., Vol. 190, No. 1-6, PP. 205-208.RussiaBlank
DS1993-0016
1993
Akimov, A.P.Akimov, A.P.Possibility of finding new natural charoite occurrencesDoklady Academy of Sciences USSR, Earth Science Section, Vol. 316, No. 2, pp. 174-177Russia, Commonwealth of Independent States (CIS)Ultrapotassic, Mineralogy
DS2002-1450
2002
Akimtsev, V.A.Sharapov, V.N., Cherepanov, A.N., Akimtsev, V.A., Cherepanova, V.K.A model of the dynamics of sublimation of lithospheric rocksDoklady Earth Sciences, Vol. 385A, 6, pp. 680-3.MantleGeodynamics
DS1997-0014
1997
Akinin, V.V.Akinin, V.V., Apt, Y.E., Ashchepkov, I.V., Lyapunov, S.The geochemistry of abyssal xenoliths from melanephelinites of northeastRussia.Doklady Academy of Sciences, Vol. 355, No. 5, Jun-July pp. 752-6.RussiaMelanephelinite
DS1997-0015
1997
Akinin, V.V.Akinin, V.V., Roden, M., Francis, D., Apt, J., Moll-StalcupCompositional and thermal state of the upper mantle beneath the Bering Seabasalt Province: evidence....Canadian Journal of Earth Sciences, Vol. 34, No. 6, June pp. 789-800.RussiaChukchi Peninsula, Basalts
DS1998-0036
1998
Akinin, V.V.Apt, Yu.E., Akinin, V.V., Wright, J.E.Strontium, neodymium, lead isotopes in Neogene melanephelinites and deep seated xenoliths from northeast Russia.Geochemistry International, Vol. 36, No. 1, Jan. pp. 24-33.RussiaXenoliths, Nephelinites
DS200612-0006
2005
Akinin, V.V.Akinin, V.V., Sobolev, A.V., Ntaflos, T., Richter, W.Clinopyroxene megacrysts from Enmelen melanephelinitic volcanoes (Chukchi Peninsula, Russia): application to composition and evolution of mantle melts.Contributions to Mineralogy and Petrology, Vol. 150, 1, pp. 85-101.RussiaNephelinite
DS201112-1059
2011
Akinin, V.V.Tschegg, C., Bizimis, M., Schneider, D., Akinin, V.V., Ntaflos, T.Magmatism at the Eurasian North American modern plate boundary: constraints from alkaline volcanism in the Chersky belt (Yakutia).Lithos, Vol. 125, pp. 825-835.Russia, YakutiaAlkaline rocks, volcanism, mantle melting
DS200412-0012
2004
Akins, J.A.Akins, J.A., Luo, S.N., Asimow, P.D., Ahrens, T.J.Shock induced melting of MgSiO3 perovskite and implications for melts in Earth's lowermost mantle.Geophysical Research Letters, Vol. 31, 14, DOI 10.1029/2004 GLO20237MantleMelt
DS200412-0068
2004
Akins, J.A.Asimow, P.D., Sun, D., Akins, J.A., Luo, S.N., Ahrens, T.J.Petrology of the lowermost mantle.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A561.MantleGeophysics - seismics
DS201804-0667
2017
Akishev, A.N.Akishev, A.N., Zyryanov, I.V., Kornilkov, S.V., Kantemirov, V.D.Improving evaluation methods for production capacity and life of open pit diamond mines.Journal of Mining Science, Vol. 53, 1, pp. 71-76.Russiadeposit - Yubileinaya

Abstract: The article reports basic design parameters of open pit mines of ALROSA, as well as criteria and factors that govern the choice of production capacity of an open pit diamond mine under conditions of permafrost. The analytical relations and tables to calculate open pit mine life are presented, and the influence of the rate of the downward advance of an open pit mine on its capacity is demonstrated. The authors formulate key provisions for a paragraph of the national standard of RF enabling systematization of approaches to optimization of open diamond mining parameters.
DS201907-1533
2019
Akishev, A.N.Cheskidov, V.I., Akishev, A.N., Sakantsev, G.G.Use of draglines in mining diamond ore deposits in Yakutia.Journal of Mining Science, Vol. 54, 4, pp. 628-637.Russia, Yakutiamining

Abstract: Potential ranges of use of draglines at steeply dipping diamond ore deposits in Yakutia are discussed. Technology of stripping with direct dumping and rehandling by draglines is substantiated for upper overburden layers. A variant of increasing height of stripping benches on haulage horizons through the use of draglines and crane lines is discussed. A resource saving technology is proposed for mining roundish and extended ore bodies with alternating advance of mining front and with internal dumping. The method of estimating efficient thickness of overburden in case of direct dumping is developed using the layer coefficient of overburden rehandling. Expediency of using blasting for displacement of broken overburden to internal dump is specified.
DS1985-0003
1985
Ako, J.A.Ako, J.A., Wellman, P.The Margin of the West African Craton: the Voltaian BasinGeological Society of London Journal, Vol. 142, No. 4, JULY, PP. 625-632.West Africa, Ghana, Togo, Benin, GhanaGeology, Geophysics, Gravity, Aeromagnetic, Seismic
DS2002-0014
2002
Akogi, M.Akogi, M., Yano, M., Suzuki, T., Koijitani, H.Phase transformation in calcium bearing silicates at high pressures and high temperatures.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.76.MantleUHP mineralogy - diopside, hedenbergite
DS202101-0018
2020
Akoh, J.Humbert, F., Elburg, M.A., Agangi, A., Belyanin, G., Akoh, J., Smith, A.J.B., Chou, Y-M., Beukes, N.J.A ~ 1.4 Ga alkaline mafic sill from the Carletonville area: connection to the Pilanesbeg alkaline province?South African Journal of Geology, Vol. 123, 4, pp. 597-614. pdfAfrica, South Africaalkaline rocks

Abstract: Numerous Mesoproterozoic alkaline intrusions belonging to the Pilanesberg Alkaline Province are present within the Transvaal sub-basin of the Kaapvaal Craton. The Pilanesberg Complex is the best-known example; it represents one of the world’s largest alkaline complexes, and is associated with a northwest-southeast trending dyke swarm that extends from Botswana to the southwest of Johannesburg. This paper documents the results of a petrological and geochemical study of a thin mafic sill (here referred to as an alkaline igneous body, AIB), which intrudes the ca. 2 200 Ma Silverton Formation close to the southernmost part of the Pilanesberg dyke swarm. The AIB has only been observed in cores from a borehole drilled close to Carletonville. It is hypocrystalline, containing randomly oriented elongated skeletal kaersutite crystals and 6 to 8 mm varioles mainly composed of radially oriented acicular plagioclase. These two textures are related to undercooling, probably linked to the limited thickness (70 cm) of the AIB coupled with a probable shallow emplacement depth. Ar-Ar dating of the kaersutite gives an age of ca. 1 400 Ma, similar to the age of Pilanesberg Complex. However, the AIB is an alkaline basaltic andesite and is thus notably less differentiated than the Pilanesberg Complex and some of its associated dykes, such as the Maanhaarrand dyke, for which we provide whole-rock geochemical data. Literature data indicate that the Pilanesberg dyke swarm also contains mafic hypabyssal rocks suggesting a link between the dyke swarm and the AIB. The AIB is characterized by strongly negative ?Nd and ?Hf, that cannot be related to crustal contamination, as shown by positive Ti and P anomalies, and the absence of negative Nb-Ta anomalies in mantle-normalised trace element diagrams. The AIB magma is interpreted to have been derived from a long-lived enriched, probably lithospheric mantle reservoir. The AIB thus provides important information on the magma source of the Pilanesberg Alkaline Province.
DS200712-0667
2007
Akon, E.Mahbubui Ameen, S.M., Wilde, S.A., Kabir, Z., Akon, E., Chowdbury, K.R., Khan, S.H.Paleoproterozoic granitoids in the basement of Bangladesh: a piece of the Indian Shield or an exotic fragment of the Gondwana jigsaw?Gondwana Research, Vol. 12, 4, pp. 380-387.IndiaIndian Shield
DS200512-0523
2005
Akram, M.Khattak, N.U., Akram, M., Ullah, K., Qureshi,L.E.Recognition of emplacement time of Jambil carbonatite complex from NW Pakistan: constraints from fission track dating of apatite using age standard approach.GAC Annual Meeting Halifax May 15-19, Abstract 1p.PakistanPeshawar Plain alkaline rocks, geochronology
DS200512-0524
2005
Akram, M.Khattak, N.U., Qureshi, A.A., Akram, M., Ullah, K., Azhar, M., Asif Khan, M.Unroofing history of the Jambil and Jawar carbonatite complexes from NW Pakistan: constraints from fission track dating of apatite.Journal of Asian Earth Sciences, Vol. 25, 4, July pp. 643-652.Asia, PakistanCarbonatite, geochronology
DS1994-0031
1994
Aksenekov, V.V.Aksenekov, V.V.The direct transmission from graphite to diamond at plastic deformation(Russian)Doklady Academy of Sciences Nauk., (Russian), Vol. 338, 4, Oct. pp. 472-476.RussiaPetrology -experimental, physics
DS201112-0264
2011
AksenenkovDenison, V.N., Mavrin, Serebryanaya, Dubitsky, Aksenenkov, Kirichenko, Kuzmin, kulnitsky, PerehoginFirst priniples, UV Raman, X-ray diffraction and TEM study of the structure and lattic dynamics of the diamond lonsdaleite system.Diamond and Related Materials, Vol. 20, 7, pp. 951-953.TechnologyLonsdaleite
DS1989-0240
1989
Aksenov, E.M.Chaikin, V.G., Tuluzako... A.V., Aksenov, E.M., Batalin, I.V.On the kimberlite magmatism in the north of theEast-EuropeanPlatform*(in Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 304, No. 4, pp. 944-946RussiaMantle, Kimberlite
DS201702-0236
2016
Aksenov, S.M.Rastsvetaeva, R.K., Chukanov, N.V., Aksenov, S.M.The crystal chemistry of lamprophyllite related minerals: a review. European Journal of Mineralogy, Vol. 28, pp. 915-930.TechnologyMineral chemistry

Abstract: The crystal structures of the lamprophyllite-related minerals are based upon HOH modules consisting of a central octahedral O sheet sandwiched between two heteropolyhedral H sheets. The general crystal-chemical formula for these minerals can be written as [10-11]A2 [[6]M1[6]M22[6]2M3X2] [[5]L2(Si2O7)2O2], where the contents of the O and H sheets are given in square brackets in this order and A = Ba, Sr, K, Na,; M1 = Na, Mn2+; M2 = Na, Mn2+, Fe2+, Ca; M3 = Ti, Mn2+, Mg, Fe3+, Fe2+; L = Ti, Fe3+; X = OH, O, F. According to the unit-cell parameters and symmetry, lamprophyllite-related minerals can be subdivided into five structure types: I (monoclinic polytypes, C2/m); II (orthorhombic polytypes, Pnmn), III (nabalamprophyllite, BaNa[Na3Ti (OH)2][Ti2(Si2O7)2O2], monoclinic, P2/m, with an ordered arrangement of the interlayer Ba2+ and Na+ cations), IV (triclinic, P1) and V (triclinic, Embedded Image ). The triclinic members (types IV and V) include schüllerite and its analogues, which differ from the lamprophyllite-group minerals sensu stricto in their symmetry and topology of the HOH modules. The end-member formulae of lamprophyllite-related minerals and the position of schüllerite in the ranks of heterophyllosilicates are discussed.
DS202011-2036
2020
Aksenov, S.M.Chukanov, N.V., Aksenov, S.M., Pekov, I.V., Belakovskiy, D.I., Vozchikova, S.A., Britvin, S.N.Sergevanite, new eudialyte group mineral from the Lovozero alkaline massif, Kola Peninsula.The Canadian Mineralogist, Vol. 58, pp. 421-436.Russia, Kola Peninsuladeposit - Lovozero

Abstract: The new eudialyte-group mineral sergevanite, ideally Na15(Ca3Mn3)(Na2Fe)Zr3Si26O72(OH)3•H2O, was discovered in highly agpaitic foyaite from the Karnasurt Mountain, Lovozero alkaline massif, Kola Peninsula, Russia. The associated minerals are microcline, albite, nepheline, arfvedsonite, aegirine, lamprophyllite, fluorapatite, steenstrupine-(Ce), ilmenite, and sphalerite. Sergevanite forms yellow to orange-yellow anhedral grains up to 1.5 mm across and the outer zones of some grains of associated eudialyte. Its luster is vitreous, and the streak is white. No cleavage is observed. The Mohs' hardness is 5. Density measured by equilibration in heavy liquids is 2.90(1) g/cm3. Calculated density is equal to 2.906 g/cm3. Sergevanite is nonpleochroic, optically uniaxial, positive, with ? = 1.604(2) and ? = 1.607(2) (? = 589 nm). The infrared spectrum is given. The chemical composition of sergevanite is (wt.%; electron microprobe, H2O determined by HCN analysis): Na2O 13.69, K2O 1.40, CaO 7.66, La2O3 0.90, Ce2O3 1.41, Pr2O3 0.33, Nd2O3 0.64, Sm2O3 0.14, MnO 4.15, FeO 1.34, TiO2 1.19, ZrO2 10.67, HfO2 0.29, Nb2O5 1.63, SiO2 49.61, SO3 0.77, Cl 0.23, H2O 4.22, -O=Cl -0.05, total 100.22. The empirical formula (based on 25.5 Si atoms pfu, in accordance with structural data) is H14.46Na13.64K0.92Ca4.22Ce0.27La0.17Nd0.12Pr0.06Sm0.02Mn1.81Fe2+0.58Ti0.46Zr2.67Hf0.04Nb0.38Si25.5S0.30Cl0.20O81.35. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is trigonal, space group R3, with a = 14.2179(1) Å, c = 30.3492(3) Å, V = 5313.11(7) Å3, and Z = 3. In the structure of sergevanite, Ca and Mn are ordered in the six-membered ring of octahedra (at the sites M11 and M12), and Na dominates over Fe2+ at the M2 site. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 7.12 (70) (110), 5.711 (43) (202), 4.321 (72) (205), 3.806 (39) (033), 3.551 (39) (220, 027), 3.398 (39) (313), 2.978 (95) (?forumla?), 2.855 (100) (404). Sergevanite is named after the Sergevan' River, which is near the discovery locality.
DS202110-1632
2021
Aksenov, S.M.Panikorovskii, T.L., Mikhailova, J.A., Pakhomovsky, y.A., Bazai, A.V., Aksenov, S.M., Kalashnikov, A.O., Krivovichev, S.V.Zr-rich eudialyte from the Lovozero peralkaline massif, Kola Peninsula, Russia.Minerals MDPI, Vol. 11, 982. 18p pdfRussia, Kola Peninsuladeposit - Lovozero

Abstract: The Lovozero peralkaline massif (Kola Peninsula, Russia) has several deposits of Zr, Nb, Ta and rare earth elements (REE) associated with eudialyte-group minerals (EGM). Eudialyte from the Alluaiv Mt. often forms zonal grains with central parts enriched in Zr (more than 3 apfu) and marginal zones enriched in REEs. The detailed study of the chemical composition (294 microprobe analyses) of EGMs from the drill cores of the Mt. Alluaiv-Mt. Kedykvyrpakhk deposits reveal more than 70% Zr-enriched samples. Single-crystal X-ray diffraction (XRD) was performed separately for the Zr-rich (4.17 Zr apfu) core and the REE-rich (0.54 REE apfu) marginal zone. It was found that extra Zr incorporates into the octahedral M1A site, where it replaces Ca, leading to the symmetry lowering from R3¯m to R32. We demonstrated that the incorporation of extra Zr into EGMs makes the calculation of the eudialyte formula on the basis of Si + Al + Zr + Ti + Hf + Nb + Ta + W = 29 apfu inappropriate.
DS1989-0252
1989
Aksenov, Ye.M.Chaykin, V.G., Tuluzkova, A.V., Aksenov, Ye.M., Batalin, Yu.V.Evidence of kimberlite magmatism in the northern part of the east European craton #2Doklady Academy of Science USSR, Earth Science Section, Vol. 304, No. 1, Jan-Feb. pp. 82-84RussiaMagmatism, Craton
DS1990-0317
1990
Aksenov, Ye.M.Chaykin, V.G., Tuluzakova, A.V., Aksenov, Ye.M., Batalin, Yu.V.Evidence of kimberlite magmatism in the northern part of the East European craton #1Doklady Academy of Science USSR, Earth Science Section, Vol. 304, No. 1-6, June, pp. 82-84RussiaCraton, Kimberlite magmatism
DS2002-0674
2002
Aksionov, N.Hatchaturov, S., Aksionov, N., Leonyuk, N.I.BHT processing of natural diamonds: new intense fancy green18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.148.GlobalDiamond - colouration
DS202205-0703
2021
Aksoy, A.Mansoor, M., Mansoor, M., Mansoor, M., Aksoy, A., Seyhan, S.N., Yildirim, B., Tahiri, A., Solak, N., Kazmanli, K., Er, Z., Czelej, K., Urgen, M.Ab-nitro calculation of point defect equilibria during heat treatment: nitrogen, hydrogen, and silicon doped diamond.Researchgate preprint Istanbul Technical University , 18p. PdfGlobaldiamond morphology

Abstract: Point defects are responsible for a wide range of optoelectronic properties in materials, making it crucial to engineer their concentrations for novel materials design. However, considering the plethora of defects in co-doped semiconducting and dielectric materials and the dependence of defect formation energies on heat treatment parameters, process design based on an experimental trial and error approach is not an efficient strategy. This makes it necessary to explore computational pathways for predicting defect equilibria during heat treatments. The accumulated experimental knowledge on defect transformations in diamond is unparalleled. Therefore, diamond is an excellent material for benchmarking computational approaches. By considering nitrogen, hydrogen, and silicon doped diamond as a model system, we have investigated the pressure dependence of defect formation energies and calculated the defect equilibria during heat treatment of diamond through ab-initio calculations. We have plotted monolithic-Kröger-Vink diagrams for various defects, representing defect concentrations based on process parameters, such as temperature and partial pressure of gases used during heat treatments of diamond. The method demonstrated predicts the majority of experimental data, such as nitrogen aggregation path leading towards the formation of the B center, annealing of the B, H3, N3, and NVHx centers at ultra high temperatures, the thermal stability of the SiV center, and temperature dependence of NV concentration. We demonstrate the possibility of designing heat treatments for a wide range of semiconducting and dielectric materials by using a relatively inexpensive yet robust first principles approach, significantly accelerating defect engineering and high-throughput novel materials design.
DS201212-0069
2012
Aktar, J.Bhaskara Rao, K.S., Patel, S.C., Ravi, S., Aktar, J.Clinopyroxene macrocrysts in Proterozoic kimberlites from southern India.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractIndiaDeposit - Wajrakarur, Narayanpet, Raichur, Tungabhadra
DS200612-0007
2006
Aktas, K.Aktas, K., Eaton, D.W.Upper mantle velocity structure of the lower Great Lakes region.Tectonophysics, Vol. 420, 1-2, pp. 267-281.Canada, OntarioGeophysics - seismics
DS1990-0107
1990
Akulov, N.I.Akulov, N.I.Facies analysis of Upper Paleozoic diamond intermediate traps ofAngaraland. (Russian)Sov. Geol., (Russian), No. 5, pp. 48-56RussiaSedimentology, Angaraland
DS1986-0071
1986
AkulshinaBessolitsyn, A.E., Ivashutin, V.I., Khmelnitskaya, T.I., AkulshinaGeology of the upper Paleozoic diamond bearing formations of Tunguskasyneclise. Geological history, paleogeography and conditions ofsedimentation.(Russian)Transactions of the Institute of Institute Geologiya i Geofizika Akademii Nauk, Vol. 646, pp. 36-92RussiaBlank
DS1986-0005
1986
Akulshina, E.P.Akulshina, E.P.Geology of the upper Paleozoic diamond bearing formations ofTunguskasynclise. Ore bearing sedimentary host rocks and prospecting criteria.(Russian)Transactions of the Institute of Institute Geologiya i Geofizika Akademii Nauk, Vol. 646, pp. 122-131RussiaBlank
DS1986-0006
1986
Akulshina, E.P.Akulshina, E.P., Betekhtina, O.A., Ivashutin, V.I., Formin, A.M.Geology of upper Paleozoic diamond bearing formations of theTunguskasynclise, methods of study.(Russian)Transactions of the Institute of Institute Geologiya i Geofizika Akademii Nauk, Vol. 646, pp. 5-19, 160-166RussiaBlank
DS201709-2070
2017
Al Ali, S.Wall., F., Al Ali, S., Rollinson, G., Fitzpatrick, R., Dawes, W., Broom-Fendley, S.Geochemistry and mineralogy of rare earth processing.Goldschmidt Conference, abstract 1p.Africa, Malawicarbonatite - Songwe Hill

Abstract: The geochemistry and mineralogy of REE deposits is diverse, from carbonatite-related deposits, alkaline rocks, mineral sands and ion adsorption clays to potential by-products of phosphate and bauxite, and reuse of waste materials. Despite the large number of prospects that have been explored recently, very little additional REE production has started. A major challenge is to design effective, cost-efficient and environmentally-friendly processing and extraction. Processing flow sheets have to be constructed carefully for each deposit. Translating geochemistry and mineralogy studies, including quantitative mineralogy results, into processing characteristics can be illustrated using results from the Songwe Hill carbonatite, Malawi. Combining results with other published data then allows us to make some general conclusions about the common REE ore minerals and their geological environment, including the REE fluorcarbonate series, monazite and xenotime. The use of chemicals for REE extraction is often the largest environmental burden to mitigate. A new issue is that certain REE, such as Ce, are in oversupply, and are not being recovered in some proposed processing flowsheets. It will be important to understand the environmental and commercial implications of this development.
DS201312-0013
2013
Al Ani, T.Al Ani, T., Sarapaa, O.Geochemistry and mineral phases of REE in Jammi carbonatite veins and fenites, southern end of the Sokli complex, NE Finland.Geochemistry: Exploration, Environment, Analysis, Vol. 13, 2, pp. 217-224.Europe, FinlandCarbonatite
DS1997-0016
1997
Al Dabbagh, M.Al Dabbagh, M., Dowd, P.A.Saudi Arabia's developing mining industryMining Ind. Int, Sept. pp. 38-44Saudi ArabiaMining, Economics
DS200812-0040
2008
Al Lazki, A.Arafin, S., Singh, R.N., George, A.K., Al Lazki, A.Thermoelastic and thermodynamic properties of harzburgite - an upper mantle rock.Journal of Physics and Chemistry of Solids, Vol. 69, 7, pp. 1766-1774.MantleGeochemistry
DS201312-0992
2013
Al QunYang, Z-j., Liang, R., Zeng, X-q., Ge, T-y., Al Qun, Zhenh, Y-l., Peng, M-s.Study on the micro-infrared spectra and origin of polycrystalline diamonds from Mengyin kimberlite pipes.Spectroscopy and Spectral Analysis, Vol. 32, 8, pp. 1512-1518.ChinaDeposit - Mengyin
DS1992-1485
1992
Alabaster, T.Storey, B.C., Alabaster, T., Hole, M.J., Pankhurst, R.J., Wever, H.E.Role of subduction-plate boundary forces during the initial stages of Gondwana break-up: evidence from the Proto-Pacific margin of Antarctica.Geological Society Special Publication, Magmatism and the Causes of Continental, No. 68, pp. 149-163.AntarcticaTectonics, Subduction
DS1992-1486
1992
Alabaster, T.Storey, B.C., Alabaster, T., Pankhurst, R.J.Magmatism and the causes of continental break-upGeological Society of London Special Publication, No. 68, 400pGondwanaBook -table of contents, Magma generation
DS1989-0734
1989
Alabert, F.Journel, A.G., Alabert, F.Non-gaussian dat a expansion in the earths sciencesTerra Nova, Vol. 1, No. 2, pp. 123-134. Database #18051GlobalComputer, Geostatistics
DS1975-0003
1975
Alabi, A.O.Alabi, A.O., Camfield, P.A., Gough, D.I.The North American Central Plains Conductive AnomalyGeophys. Journal of Res. Astron. Soc., Vol. 43, PP. 815-833.GlobalGeophysics, Mid-continent
DS1993-0017
1993
Ala-Harkonen, M.Ala-Harkonen, M.Corporate growth and diversification paths within the minerals industryCentre for Resource Studies, CRS Perspectives, No. 44, May/June pp. 2-17GlobalEconomics, Mineral industry
DS1993-0018
1993
Ala-Harkonen, M.Ala-Harkonen, M.Technical innovation and competitiveness in the minerals industriesCentre for Resource Studies, p? $ 15.00GlobalEconomics, Mineral industry -competitiveness
DS1993-0019
1993
Ala-Harkonen, M.Ala-Harkonen, M., Rutenberg, D.The dawn of organizational learning in the mining industryResources Policy, Vol. 19, No. 3, September pp. 205-216GlobalEconomics, Mining industry -learning curve
DS1992-1499
1992
Alam, M.Sun, Q., Alam, M.Relative oxidation behavior of chemical vapor-deposited and type IIA natural diamondsJ. Elchem. So, Vol. 139, No. 3, March pp. 933-936. # hh077GlobalNatural diamonds, CVD.
DS2002-0140
2002
Alammar, A.Berendsen, P., Barczuk, A., Alammar, A.New dat a on Late Cretaceous kimberlites and lamproites in Kansas16th. International Conference On Basement Tectonics '02, Abstracts, 2p., 2p.KansasMineralogy, petrology, Tuttle, Antich, Baldwin Creek
DS2003-0101
2003
Al-Ammar, A.Berendsen, P., Cullers, R.L., Barczuk, A., Al-Ammar, A.New dat a on kimberlites and lamproites in eastern Kansas, U.S.A8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractKansasKimberlite geology and economics
DS200812-0848
2008
Al-Amri, A.Park, Y., Nyblade, A.A., Rodgers, A.J., Al-Amri, A.S wave velocity structure of the Arabian shield upper mantle from Rayleigh wave tomography.Geochemistry, Geophysics, Geosystems: G3, in press available, 50p.MantleTomography
DS1989-0414
1989
Alaniz, M.A.Everitt, J.H., Escobar, D.E., Alaniz, M.A., Davis, M.R.Using multispectral video imagery for detecting soil surface conditionsPhotogrammetric Engineering and Remote Sensing, Vol. LV, No. 4, April pp. 467-472GlobalRemote Sensing, Landsat soil surface
DS1998-0016
1998
Alaniz-Alvarez, S.S.Alaniz-Alvarez, S.S., Nieto-Samaniego, A., Ferrari, L.Effect of strain rate in the distribution of monogenetic and polygenetic volcanism in the volcanicsGeology, Vol. 26, No. 7, July, pp. 591-4MexicoTransmexican volcanic belt, Tectonics
DS1999-0397
1999
AlapietiLatypov, R.M., Mitrofanov, F.P., Alapieti, KaukkonenPetrology of the upper layered horizon of the West Pansky tundra intrusion( Kola Peninsula).Russian Geology and Geophysics, Vol. 40, No. 10, pp. 1413-36.Russia, Kola PeninsulaLayered intrusion
DS1999-0396
1999
AlapiettiLatypov, R.M., Mitrofanov, Alapietti, HalkoahoPetrology of the lower layered horizon of the Western Pansky TundraIntrusion, Kola Peninsula.Petrology, Vol. 7, No. 5, pp. 482-508.Russia, Kola PeninsulaLayered intrusion - not specific to diamonds
DS1998-0892
1998
AlardLorand, J.P., Luguet, A., Keays, AlardSelenium contents and Sulphur/Selenium ratios of spinel peridotite xenoliths from the massif central France.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 903-4.FranceMantle - peridotites
DS2002-0229
2002
AlardBurton, K.W., Gannoun, Birck, Allegre, Schiano,AlardThe compatibility of rhenium and osmium in natural olivine and their behaviour during mantle melting...Earth and Planetary Science Letters, Vol.198,1-2,pp.63-76., Vol.198,1-2,pp.63-76.MantleMineralogy - olivine, Basalt genesis
DS2002-0230
2002
AlardBurton, K.W., Gannoun, Birck, Allegre, Schiano,AlardThe compatibility of rhenium and osmium in natural olivine and their behaviour during mantle melting...Earth and Planetary Science Letters, Vol.198,1-2,pp.63-76., Vol.198,1-2,pp.63-76.MantleMineralogy - olivine, Basalt genesis
DS2001-0700
2001
Alard, A.Lorand, J.P., Alard, A.Platinum group element abundances in the upper mantle: new constraints from in situ and whole rock analysesGeochimica et Cosmochimica Acta, Vol. 65, No. 16, pp. 2789-1806.FranceXenoliths, Massif Central
DS1998-0017
1998
Alard, O.Alard, O., Luguet, Lorand, Powell, O'Reilly, GriffinFurther insights on S content and behaviour in the lithospheric mantleMineralogical Magazine, Goldschmidt abstract, Vol. 62A, pp. 29-30.Australia, FranceSulphide mineralogy, Xenoliths
DS1998-0826
1998
Alard, O.Lambert, D.D., Alard, O., Costa, S., Frick, BodinierEvidence for interaction of Proterozoic (2 Ga) sub-continental mantle wit han enriched mantle plume...Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 848-9.FranceMelt depletion, peridotite xenoliths, Franch Massif Central
DS2000-0011
2000
Alard, O.Alard, O., Griffin, W.L., O'Reilly, S.Y.Non chondritic distribution of the highly siderphile elements in mantle sulphides.Nature, Vol. 407, No. 6806, Oct. 19, p.891-3.MantleSulphides
DS2000-0314
2000
Alard, O.Garrido, C.J., Bodinier, J.L., Alard, O.Incompatible trace element partioning and residence in anhydrous spinel peridotites and websterites from RondaEarth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.327-40.GlobalPeridotites, Deposit - Ronda
DS2001-0706
2001
Alard, O.Luguet, A., Alard, O., Lorand, Pearson, Ryan, O'ReillyLaser ablation microprobe LAM ICPMS unravels the highly siderophile element geochemistry of oceanic mantle.Earth and Planetary Science Letters, Vol. 189, No. 3-4, July 15, pp. 285-94.MantleGeochemistry
DS2002-0015
2002
Alard, O.Alard, O., Griffin, W.L., Pearson, N.J., Lorand, J.P., O'Reilly, S.Y.New insights into the Re Os systematics of sub-continental lithospheric mantle from an insitu analysis of sulphides.Earth and Planetary Science Letters, Vol. 203, 3, pp. 651-663.MantleGeochronology
DS2002-1236
2002
Alard, O.Pearson, N.J., Alard, O., Griffin, Jackson, O'ReillyIn situ measurement of Re Os isotopes in mantle sulfides by laser ablation multicollector inductively..Geochimica et Cosmochimica Acta, Vol. 66, 6, pp. 1037-50.Russia, Siberia, Northwest TerritoriesCraton - mass spectrometry, rhenium, osmium, Peridotites
DS2003-0839
2003
Alard, O.Lorand, J.P., Alard, O., Luguet, A., Keays, R.R.Sulfur and selenium systematics of the subcontinental lithospheric mantle: inferencesGeochimica et Cosmochimica Acta, Vol. 67, 21, pp. 4137-51.FranceGeochemistry - not specific to diamonds
DS200412-1172
2003
Alard, O.Lorand, J.P., Alard, O., Luguet, A., Keays, R.R.Sulfur and selenium systematics of the subcontinental lithospheric mantle: inferences from the Massif Central Xenolith suite.Geochimica et Cosmochimica Acta, Vol. 67, 21, pp. 4137-51.Europe, FranceGeochemistry - not specific to diamonds
DS200512-0008
2005
Alard, O.Alard, O., Luguet, A., Pearson, N.J., Griffin, W.L., Lorand, J.P., Gannoun, A., Burton, K.W., O'Reilly, S.Y.In situ Os isotopes in abyssal peridotites bridge the isotopic gap between MORBS and their source mantle.Nature, Vol. 436, No. 7053, Aug. 18, pp. 1005-1108.MantleGeochronology
DS200612-0008
2006
Alard, O.Alard, O.Ancient abyssal peridotites.GEMOC Annual Report, 2005, p. 34-35.MantleMagmnatism, tectonics
DS200612-0009
2006
Alard, O.Alard, O.Most abyssal peridotites are old.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 6, abstract only.GlobalGeochronology
DS200612-1061
2006
Alard, O.Pearson, N.J., Griffin, W.L., Alard, O., O'Reilly, S.Y.The isotopic composition of magnesium in mantle olivine: records of depletion and metasomatism.Chemical Geology, Vol. 226, 3-4, pp. 115-133.Russia, Canada, Northwest Territories, AustraliaGeochronology
DS200712-0603
2007
Alard, O.Le Roux, V., Bodinier, J-L., Alard, O., Wieland, P., O'Reilly, S.Y.Insights into refertilization processes in lithospheric mantle from integrated isotopic studies in the Lherz Massif.Plates, Plumes, and Paradigms, 1p. abstract p. A563.Europe, FranceMelting
DS200712-0604
2007
Alard, O.Le Roux, V., Bodinier, J-L., Tommasi, A., Alard, O., Dautria, J-M., Vauchez, A., Riches, A.J.V.The lherz spinel lherzolite: refertilized rather than pristine mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 599-612.MantleLherzolite chemistry
DS200712-0605
2007
Alard, O.Le Roux, V., Bodinier, J-L., Tommasi, A., Alard, O., Dautria, J-M., Vauchez, A., Riches, A.J.V.The lherz spinel lherzolite: refertilized rather than pristine mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 599-612.MantleLherzolite chemistry
DS200712-0823
2006
Alard, O.Pearson, D.J., O'Reilly, S.Y., Griffin, W.L., Alard, O., Belousova, E.Linking crustal and mantle events using in situ trace element and isotope analysis.Geochimica et Cosmochimica Acta, In press availableMantleGeochronology
DS200812-0011
2008
Alard, O.Alard, O., Le Roux, V., Bodinier, J.L., Lorand, J.P., Griffin, W.L., O'Reilly, S.Y.How primitive is the 'primitive' mantle?Goldschmidt Conference 2008, Abstract p.A13.MantleGeochemistry, structure
DS200812-0829
2008
Alard, O.O'Reilly, S.Y., Griffin, W.L., Pearson, N.J., Jackson, S.E., Belousova, E.A., Alard, O., Saeed, A.Taking the pulse of the Earth: linking crustal and mantle events.Australian Journal of Earth Sciences, Vol. 55, pp. 983-995.MantleGeochronology
DS201112-0010
2001
Alard, O.Alard, O.Chalcophile and siderophile elements in the mantle: geochemical characteristics and distribution.Thesis: Macquarie University Phd. , MantleThesis: note availability based on request to author
DS201112-0386
2011
Alard, O.Greau, Y., Huang, J-X., Griffin, W.L., Renac, C., Alard, O., O'Reilly, S.Y.Type 1 eclogite from Roberts Victor kimberlites: products of extensive mantle metasomatism.Geochimica et Cosmochimica Acta, Vol. 75, 22, pp. 6927-2954.Africa, South AfricaDeposit - Roberts Victor
DS201312-0333
2013
Alard, O.Greau, Y., Alard, O., Griffin, W.L., Huang, J-X., O'Reilly, S.Y.Sulfides and chalcophile elements in Roberts Victor eclogites: unravelling a sulfide rich metasomatic event.Chemical Geology, Vol. 354, pp. 73-92.Africa, South AfricaDeposit - Roberts Victor
DS201412-0478
2014
Alard, O.Kourim, F., Bodinier, J-L., Alard, O., Bendaoud, A., Vauchez, A., Dautria, J-M.Nature and evolution of the lithospheric mantle beneath the Hoggar Swell ( Algeria): a record from mantle xenoliths.Journal of Petrology, Vol. 55, pp. 2249-2280.Africa, AlgeriaXenoliths
DS201805-0940
2018
Alard, O.Chasse, M., Griffin, W.L., Alard, O., O'Reilly, S.Y., Calas, G.Insights into the mantle geochemistry of scandium from a meta-analysis of garnet data. GEOROC databaseLithos, in press available 47p.Mantlemetasomatism

Abstract: he meta-analysis of about 13,000 analyses of scandium content in garnet grains shows that, below the spinel-garnet transition, this phase carries about three-quarters of the Sc budget of the mantle, indicating its control on Sc mobility. The Sc content of garnets in mafic rocks is low, due to a dilution effect resulting from their high modal content in garnet. Garnets from ultramafic rocks exhibit a wider range of Sc concentrations. We assess the relative influence of thermobarometry, crystal chemistry and fluid-related events on the distribution of Sc in garnet from such rocks to improve the tracking of geochemical processes in the mantle. Pressure and temperature of equilibration in the mantle are second-order factors influencing the Sc content of garnet, while crystal-chemistry, in particular and , is the main parameter controlling the compatibility of Sc. Scandium is incorporated in both X and Y sites of Cr-Ca-rich garnets, resulting in a behaviour intermediate between rare-earth elements, incorporated in the X site, and trivalent transition elements, occupying the Y site. This affinity for both sites results in a mild compatibility of Sc in the garnet stability field of the mantle; hence Sc concentration in garnet increases with melt extraction and can be reduced by silicate-melt metasomatism. In contrast, metasomatism by volatile-rich fluids increases the Sc concentration in garnet. The control of garnet on the compatibility of Sc in deep lithospheric rocks demonstrates the potential of using Sc to track the conditions of formation of magmas and their residual rocks, as well as the origin and nature of metasomatic fluids.
DS201907-1545
2019
Alard, O.Forster, M.W., Foley, S.F., Marschall, H.R., Alard, O., Buhre, S.Melting of sediments in the deep mantle produces saline fluid inclusions in diamonds.Science Advances, Vol. 5, 5, eaau 2620 7p.Mantlediamond inclusions

Abstract: Diamonds growing in the Earth’s mantle often trap inclusions of fluids that are highly saline in composition. These fluids are thought to emerge from deep in subduction zones and may also be involved in the generation of some of the kimberlite magmas. However, the source of these fluids and the mechanism of their transport into the mantle lithosphere are unresolved. Here, we present experimental results showing that alkali chlorides are stable solid phases in the mantle lithosphere below 110 km. These alkali chlorides are formed by the reaction of subducted marine sediments with peridotite and show identical K/Na ratios to fluid inclusions in diamond. At temperatures >1100°C and low pressures, the chlorides are unstable; here, potassium is accommodated in mica and melt. The reaction of subducted sediments with peridotite explains the occurrence of Mg carbonates and the highly saline fluids found in diamonds and in chlorine-enriched kimberlite magmas.
DS201909-2039
2019
Alard, O.Forster, M.W., Foley, S.F., Alard, O., Buhre, S.Partitioning of nitrogen during melting and recycling in subduction zones and the evolution of atmospheric nitrogen.Chemical Geology, in press available 31p. PdfMantlesubduction, metasomatism

Abstract: The subduction of sediment connects the surface nitrogen cycle to that of the deep Earth. To understand the evolution of nitrogen in the atmosphere, the behavior of nitrogen during the subduction and melting of subducted sediments has to be estimated. This study presents high-pressure experimental measurements of the partitioning of nitrogen during the melting of sediments at sub-arc depths. For quantitative analysis of nitrogen in minerals and glasses, we calibrated the electron probe micro-analyzer on synthetic ammonium feldspar to measure nitrogen concentrations as low as 500??g?g?1. Nitrogen abundances in melt and mica are used together with mass balance calculations to determine DN(Mica/Melt), DN(Fluid/Mica), and DN(Fluid/Melt). Calculated partition coefficients correspond to expected values for NH4+, which behaves similarly to Rb+ due to its nearly identical size. Nitrogen partitioning between fluid and melt (DN(Fluid/Melt)) and fluid and bulk residue (melt+mica) (DN(Fluid/Bulk)) increase linearly with temperature normalized to pressure. This linear relationship can be used to calculate DN(Fluid/Melt) and DN(Fluid/Bulk) for slab melts from 800 to 1200?°C following: and [nasty equation that did not copy]. We used these partition coefficients to quantify the amount of N recycled into the mantle as 50?±?6% of today's atmospheric N. Depending on the rate of mantle N degassing we calculated 4 different scenarios for atmospheric pN2 evolution. All 4 scenarios estimate pN2 to be 8-12% higher at the beginning of the Phanerozoic. These estimates diverge towards the past due to uncertainties in the mechanism and magnitude of N degassing from the mantle. Assuming degassing of N in the past was close to modern degassing rates from MORB, pN2 was up to 40% higher at the onset of plate tectonics at 3-4?Ga. However, degassing rates were probably higher than this: assuming 10× and 20× times higher rates at the onset of plate tectonics leads to pN2 within 20% of modern values. If N degassing from the mantle is increased to 40× the modern MORB rate, pN2 in the Archean would have been 50% lower than today's, which is in accordance with observations from paleoatmospheric studies.
DS201911-2541
2019
Alard, O.Liu, J., Pearson, D.G., Shu, Q., Sigurdsson, H., Thomassot, E., Alard, O.Dating the post-Archean lithospheric mantle: insights from Re-Os and Lu-Hf isotopic systematics of the Cameroon volcanic line peridotites.Geochimica et Cosmochimica Acta, in press available. 13p.Africa, Cameroonperidotite

Abstract: Highly depleted Archean peridotites have proven very amenable to Re-Os model age dating. In contrast, due to the increasing heterogeneity of mantle Os isotope compositions with time, the Re-Os system has not been as effective in dating post-Archean peridotites. The timing of depletion and accretion of post-Archean lithospheric mantle around cratons is important to understand within the context of the evolution of the continents. In an attempt to precisely date post-Archean peridotite xenoliths, we present a study of the petrology, mineralogy and geochemistry, including whole-rock Re-Os isotopes, highly siderophile elements and clinopyroxene-orthopyroxene Sr-Nd-Hf isotopes of peridotite xenoliths from Lake Nyos in the Cameroon Volcanic Line (CVL). Eight Nyos peridotite xenoliths, all fresh spinel lherzolites, are characterized by low to moderate olivine Fo contents (88.9-91.2) and low spinel Cr# (8.4-19.3), together with moderate to high whole-rock Al2O3 contents (2.0-3.7%). These chemical characteristics indicate that they are mantle residues of a few percent to <20% partial melting. However, trace element patterns of both clinopyroxene and orthopyroxene are not a pristine reflection of melt depletion but instead show various extents of evidence of metasomatic enrichment. Some of the samples contain orthopyroxene with 143Nd/144Nd lower than its coexisting clinopyroxene, which is best explained by recent short-timescale alteration, most likely by infiltration of the host basalt. Because of these metasomatic effects, the Sr-Nd isotope systematics in pyroxenes cannot sufficiently reflect melt depletion signatures. Unlike Sr-Nd isotopes, the Lu-Hf isotope system is less sensitive to recent metasomatic overprinting. Given that orthopyroxene hosts up to 33% of the Lu and 14% of the Hf in the whole rock budget of these rocks and has 176Hf/177Hf similar to, or higher than, coexisting clinopyroxene, it is necessary to reconstruct a whole-rock Lu-Hf isochron in order to constrain the melt depletion age of peridotites. The reconstructed Nyos Lu-Hf isochron from ortho- and clinopyroxenes gives an age of 2.01?±?0.18?Ga (1?), and when olivine and spinel are considered, is 1.82?±?0.14?Ga (1?). Both ages are identical within error, and they are within error of the alumina-187Os/188Os pseudo-isochron ages (1.2-2.4?Ga) produced on the peridotites from Lake Nyos, consistent with their oldest rhenium depletion Os model ages (2.0?Ga). We conclude that the Nyos peridotites, and the lithospheric mantle that they represent, were formed at ?2.0?Ga, indicating that the reconstructed whole-rock Lu-Hf isotope system can be a powerful radiometric dating tool that is complementary to and in some instances, more precise than the Re-Os isotope system in dating well-preserved post-Archean peridotites. The recognition of ?2.0?Ga subcontinental lithospheric mantle (SCLM) in the Nyos area suggests that the Nyos region was assembled as a Paleoproterozoic block, or that it represents fragments of the SCLM from the nearby Paleoproterozoic domain juxtaposed through collisional emplacement during the Pan African Orogeny. With regards to the origin of the CVL, our data reveal that the Hf isotopic compositions of the Nyos peridotites are too radiogenic to be the main source of the CVL basalts.
DS202002-0219
2020
Alard, O.Tilhac, R., Oliveira, B., Griffin, W.L., O'Reilly, S.Y., Schaefer, B.F., Alard, O., Ceuleneer, G., Afonso, J.C., Gregoire, M.Reworking of old continental lithosphere: unradiogenic Os and decoupled Hf-Nd isotopes in sub-arc mantle pyroxenites.Lithos, Vol. 354-355, 19p. pdfEurope, Spainpyroxenites

Abstract: Mantle lithologies in orogenic massifs and xenoliths commonly display strikingly different Hf- and Nd-isotope compositions compared to oceanic basalts. While the presence of pyroxenites has long been suggested in the source region of mantle-derived magmas, very few studies have reported their combined HfNd isotope compositions. We here report the first LuHf data along with ReOs data and S concentrations on the Cabo Ortegal Complex, where the pyroxenite-rich Herbeira massif has been interpreted as remnants of a delaminated arc root. The pyroxenites, chromitites and their host harzburgites show a wide range of whole-rock 187Re/188Os and 187Os/188Os (0.16-1.44), indicating that Re was strongly mobilized, partly during hydrous retrograde metamorphism but mostly during supergene alteration that preferentially affected low-Mg#, low Cu/S pyroxenites. Samples that escaped this disturbance yield an isochron age of 838 ± 42 Ma, interpreted as the formation of Cabo Ortegal pyroxenites. Corresponding values of initial 187Os/188Os (0.111-0.117) are relatively unradiogenic, suggesting limited contributions of slab-derived Os to primitive arc melts such as those parental to these pyroxenites. This interpretation is consistent with radiogenic Os in arc lavas being mostly related to crustal assimilation. Paleoproterozoic to Archean Os model ages confirm that Cabo Ortegal pyroxenites record incipient volcanic arc magmatism on the continental margin of the Western African Craton, as notably documented by zircon UPb ages of 2.1 and 2.7 Ga. LuHf data collected on clinopyroxene and amphibole separates and whole-rock samples are characterized by uncorrelated 176Lu/177Hf and 176Hf/177Hf (0.2822-0.2855), decoupled from Nd-isotope compositions. This decoupling is ascribed to diffusional disequilibrium during melt-peridotite interaction, in good agreement with the results of percolation-diffusion models simulating the interaction of an arc melt with an ancient melt-depleted residue. These models notably show that HfNd isotopic decoupling such as recorded by Cabo Ortegal pyroxenites and peridotites (??Hf(i) up to +97) is enhanced during melt-peridotite interaction by slow diffusional re-equilibration and can be relatively insensitive to chromatographic fractionation. Finally, we discuss the hypothesis that arc-continent interaction may provide preferential conditions for such isotopic decoupling and propose that its ubiquitous recognition in peridotites reflects the recycling of sub-arc mantle domains derived from ancient, reworked SCLM.
DS202006-0932
2020
Alard, O.Liu, J., Pearson, D.G., Shu, Q., Sigurdsson, H., Thomassot, E., Alard, O.Dating post-Archean lithospheric mantle: insights from Re-Os and Lu-Hf isotopic systematics of the Cameroon volcanic line peridotites.Geochimica et Cosmochimica Acta, Vol. 278, pp. 177-198.Africa, Cameroonperidotites

Abstract: Highly depleted Archean peridotites have proven very amenable to Re-Os model age dating. In contrast, due to the increasing heterogeneity of mantle Os isotope compositions with time, the Re-Os system has not been as effective in dating post-Archean peridotites. The timing of depletion and accretion of post-Archean lithospheric mantle around cratons is important to understand within the context of the evolution of the continents. In an attempt to precisely date post-Archean peridotite xenoliths, we present a study of the petrology, mineralogy and geochemistry, including whole-rock Re-Os isotopes, highly siderophile elements and clinopyroxene-orthopyroxene Sr-Nd-Hf isotopes of peridotite xenoliths from Lake Nyos in the Cameroon Volcanic Line (CVL). Eight Nyos peridotite xenoliths, all fresh spinel lherzolites, are characterized by low to moderate olivine Fo contents (88.9-91.2) and low spinel Cr# (8.4-19.3), together with moderate to high whole-rock Al2O3 contents (2.0-3.7%). These chemical characteristics indicate that they are mantle residues of a few percent to <20% partial melting. However, trace element patterns of both clinopyroxene and orthopyroxene are not a pristine reflection of melt depletion but instead show various extents of evidence of metasomatic enrichment. Some of the samples contain orthopyroxene with 143Nd/144Nd lower than its coexisting clinopyroxene, which is best explained by recent short-timescale alteration, most likely by infiltration of the host basalt. Because of these metasomatic effects, the Sr-Nd isotope systematics in pyroxenes cannot sufficiently reflect melt depletion signatures. Unlike Sr-Nd isotopes, the Lu-Hf isotope system is less sensitive to recent metasomatic overprinting. Given that orthopyroxene hosts up to 33% of the Lu and 14% of the Hf in the whole rock budget of these rocks and has 176Hf/177Hf similar to, or higher than, coexisting clinopyroxene, it is necessary to reconstruct a whole-rock Lu-Hf isochron in order to constrain the melt depletion age of peridotites. The reconstructed Nyos Lu-Hf isochron from ortho- and clinopyroxenes gives an age of 2.01?±?0.18?Ga (1?), and when olivine and spinel are considered, is 1.82?±?0.14?Ga (1?). Both ages are identical within error, and they are within error of the alumina-187Os/188Os pseudo-isochron ages (1.2-2.4?Ga) produced on the peridotites from Lake Nyos, consistent with their oldest rhenium depletion Os model ages (2.0?Ga). We conclude that the Nyos peridotites, and the lithospheric mantle that they represent, were formed at ?2.0?Ga, indicating that the reconstructed whole-rock Lu-Hf isotope system can be a powerful radiometric dating tool that is complementary to and in some instances, more precise than the Re-Os isotope system in dating well-preserved post-Archean peridotites. The recognition of ?2.0?Ga subcontinental lithospheric mantle (SCLM) in the Nyos area suggests that the Nyos region was assembled as a Paleoproterozoic block, or that it represents fragments of the SCLM from the nearby Paleoproterozoic domain juxtaposed through collisional emplacement during the Pan African Orogeny. With regards to the origin of the CVL, our data reveal that the Hf isotopic compositions of the Nyos peridotites are too radiogenic to be the main source of the CVL basalts.
DS202010-1846
2020
Alard, O.Gorojovsky, L., Alard, O.Optimization of laser and mass spectrometer parameters for the in situ analysis of Rb/Sr ratios by LA-ICP-MS/MS. ( mentions Monastery phlogopite megacrystJournal of Analytical Atomic Spectrometry, 10.1039/DOJA00308E 15p. PdfGlobalgeochronology

Abstract: The Rb-Sr isotopic system is widely used in geochronology. Conventionally burdened by the isobaric overlap of 87Rb and 87Sr, Rb/Sr dating in situ has only recently become achievable with the newly developed LA-ICP-MS/MS system. Simultaneous use of reactive gas (e.g. O2, N2O, or CH3F) during LA-ICP-MS/MS analysis has been shown to resolve the Rb and Sr overlap, thus now making available key spatial and temporal information that can only be accessed via in situ analytical techniques. The accuracy and precision of Rb/Sr ratios and ages are largely dependent on the laser and ICP-MS/MS parameters used. Rb/Sr isotopic analysis by LA-ICP-MS/MS is a recently developed technique and these parameters are yet to be fully explored. We investigate the effects of laser wavelength (213 nm and 193 nm), laser frequency (5 Hz and 10 Hz), laser carrier gas (He, H2, and N2), dwell time, and external standard calibration on the accuracy and precision of 87Rb/86Sr and 87Sr/86Sr ratios and ages. These analytical conditions have been tested on the commercially available reference materials: NIST SRM 610, USGS BHVO-2G, and pressed nano-particulate powder tablet CRPG Mica-mg, as well as a Monastery phlogopite megacryst. Our results show that accuracy and precision for 87Rb/86Sr and 87Sr/86Sr ratios are significantly affected by laser wavelength and frequency. Variation in these parameters can strongly magnify any matrix effects which directly influences the ability to apply effective external corrections. We obtain the best accuracy and precision when using a 193 nm laser wavelength, ablating at a frequency of 5 Hz (0.30 2s% and 0.15 2s% for 87Rb/86Sr and 87Sr/86Sr ratios, respectively). Meanwhile we find that age accuracy is highly dependant on external reference materials. When these analytical settings are put to test on the Monastery phlogopite, we obtain an age of 90.0 ± 3.6 (0.24% accuracy) when using mica-mg (87Rb/86Sr) and NIST 610 (87Sr/86Sr) as external standards.
DS202012-2217
2020
Alard, O.Griffin, W.L., Gain, S.E.M., Saunders, M., Bindi, L., Alard, O., Toledo, V., O'Reilly, S.Y.Parageneses of TiB2 in corundum xenoliths from Mt. Carmel, Israel: siderophile behavior of boron under reducing conditions.American Mineralogist, Vol. 105, pp. 1609-1621. pdfEurope, Israeldeposit - Mt. Carmel

Abstract: Titanium diboride (TiB2) is a minor but common phase in melt pockets trapped in the corundum aggregates that occur as xenoliths in Cretaceous basaltic volcanoes on Mt. Carmel, north Israel. These melt pockets show extensive textural evidence of immiscibility between metallic (Fe-Ti-C-Si) melts, Ca-Al-Mg-Si-O melts, and Ti-(oxy)nitride melts. The metallic melts commonly form spherules in the coexisting oxide glass. Most of the observed TiB2 crystallized from the Fe-Ti-C silicide melts and a smaller proportion from the oxide melts. The parageneses in the melt pockets of the xenoliths require fO2 ? ?IW-6, probably generated through interaction between evolved silicate melts and mantle-derived CH4+H2 fluids near the crust-mantle boundary. Under these highly reducing conditions boron, like carbon and nitrogen, behaved mainly as a siderophile element during the separation of immiscible metallic and oxide melts. These parageneses have implications for the residence of boron in the peridotitic mantle and for the occurrence of TiB2 in other less well-constrained environments such as ophiolitic chromitites.
DS202101-0013
2020
Alard, O.Griffin, W.L., Gain, S.E.M., Saunders, M., Bindi, L., Alard, O., Toledo, V., O'Reilly, S.Y.Parageneses of TIB2 in corundum xenoliths from Mt. Carmel, Israel: siderophile behaviour of boron under reducing conditions.American Mineralogist , in press available 33p. PdfEurope, Israeldeposit - Mt. Carmel

Abstract: Titanium diboride (TiB2) is a minor but common phase in melt pockets trapped in the corundum aggregates that occur as xenoliths in Cretaceous basaltic volcanoes on Mt. Carmel, north Israel. These melt pockets show extensive textural evidence of immiscibility between metallic (Fe-Ti-C-Si) melts, Ca-Al-Mg-Si-O melts, and Ti-(oxy)nitride melts. The metallic melts commonly form spherules in the coexisting oxide glass. Most of the observed TiB2 crystallized from the Fe-Ti-C silicide melts and a smaller proportion from the oxide melts. The parageneses in the melt pockets of the xenoliths require fO2 ? ?IW-6, probably generated through interaction between evolved silicate melts and mantle-derived CH4+H2 fluids near the crust-mantle boundary. Under these highly reducing conditions boron, like carbon and nitrogen, behaved mainly as a siderophile element during the separation of immiscible metallic and oxide melts. These parageneses have implications for the residence of boron in the peridotitic mantle and for the occurrence of TiB2 in other less well-constrained environments such as ophiolitic chromitites.
DS202108-1286
2021
Alard, O.Griffin, W.L., Gain, S.E.M., Saunders, M., Alard, O., Shaw, J., Toledo, V.Nitrogen under super-reducing conditions: Ti Oxynitride melts in xenolithic corundum aggregates from Mt. Carmel.Minerals, Vol. 11, 780, 16p. PdfEurope, Israeldeposit - Mt. Carmel

Abstract: Titanium oxynitrides (Ti(N,O,C)) are abundant in xenolithic corundum aggregates in pyroclastic ejecta of Cretaceous volcanoes on Mount Carmel, northern Israel. Petrographic observations indicate that most of these nitrides existed as melts, immiscible with coexisting silicate and Fe-Ti-C silicide melts; some nitrides may also have crystallized directly from the silicide melts. The TiN phase shows a wide range of solid solution, taking up 0-10 wt% carbon and 1.7-17 wt% oxygen; these have crystallized in the halite (fcc) structure common to synthetic and natural TiN. Nitrides coexisting with silicide melts have higher C/O than those coexisting with silicate melts. Analyses with no carbon fall along the TiN-TiO join in the Ti-N-O phase space, implying that their Ti is a mixture of Ti3+ and Ti2+, while those with 1-3 at.% C appear to be solid solutions between TiN and Ti0.75O. Analyses with >10 at% C have higher Ti2+/Ti3+, reflecting a decrease in fO2. Oxygen fugacity was 6 to 8 log units below the iron-wüstite buffer, at or below the Ti2O3-TiO buffer. These relationships and coexisting silicide phases indicate temperatures of 1400-1100 °C. Ti oxynitrides are probably locally abundant in the upper mantle, especially in the presence of CH4-H2 fluids derived from the deeper metal-saturated mantle.
DS202204-0520
2022
Alard, O.Griffin, W.L., Gain, S.E.M., Saunders, M.J., Huang, J-X., Alard, O., Toledo, V., O'Reilly, S.Y.Immiscible metallic melts in the upper mantle beneath Mount Carmel, Israel: silicides, phosphides, and carbides.American Mineralogist, Vol. 107, pp. 532-549.Europe, Israeldeposit - Mount Carmel

Abstract: Xenolithic corundum aggregates in Cretaceous mafic pyroclastics from Mount Carmel contain pockets of silicate melts with mineral assemblages [SiC (moissanite), TiC, Ti2O3 (tistarite), Fe-Ti-Zr silicides/phosphides] indicative of magmatic temperatures and oxygen fugacity (fO2) at least 6 log units below the iron-wüstite buffer (?IW ? -6). Microstructural evidence indicates that immiscible, carbon-rich metallic (Fe-Ti-Zr-Si-P) melts separated during the crystallization of the silicate melts. The further evolution of these metallic melts was driven by the crystallization of two main ternary phases (FeTiSi and FeTiSi2) and several near-binary phases, as well as the separation of more evolved immiscible melts. Reconstructed melt compositions fall close to cotectic curves in the Fe-Ti-Si system, consistent with trapping as metallic liquids. Temperatures estimated from comparisons with experimental work range from ?1500 °C to ca. 1150 °C; these probably are maximum values due to the solution of C, H, P, and Zr. With decreasing temperature (T), the Si, Fe, and P contents of the Fe-Ti-Si melts increased, while contents of Ti and C decreased. The increase in Si with declining T implies a corresponding decrease in fO2, probably to ca. ?IW-9. The solubility of P in the metallic melts declined with T and fO2, leading to immiscibility between Fe-Ti-Si melts and (Ti,Zr)-(P,Si) melts. Decreasing T and fO2 also reduced the solubility of C in the liquid metal, driving the continuous crystallization of TiC and SiC during cooling. The lower-T metallic melts are richer in Cr, and to some extent V, as predicted by experimental studies showing that Cr and V become more siderophile with decreasing fO2. These observations emphasize the importance of melt-melt immiscibility for the evolution of magmas under reducing conditions. The low fO2 and the abundance of carbon in the Mt. Carmel system are consistent with a model in which differentiating melts were fluxed by fluids that were dominated by CH4+H2, probably derived from a metal-saturated sublithospheric mantle. A compilation of other occur-rences suggests that these phenomena may commonly accompany several types of explosive volcanism.
DS201702-0226
2016
Alarie, E.Martin, R.F., Alarie, E., Minarik, W.G., Waczek, Z., McCammon, C.A.Titanium rich magneso-hastingite macrocrysts in a camptonite dike, Lafarge quarry, Montreal Island, Quebec: early crystallization in a pseudo-unary system.The Canadian Mineralogist, Vol. 54, pp. 65-78.Canada, QuebecCamptonite

Abstract: A prominent dike of camptonite cuts the Middle Ordovician Tétreauville Formation of the Trenton Group in the Montréal-Est quarry operated by Lafarge Canada Inc. The “Lafarge” dike is strikingly porphyritic, with largely anhedral macrocrysts of unzoned calcic amphibole up to 13 cm across. The macrocrysts are rimmed with ferri-kaersutite resembling the amphibole in the fine-grained matrix of the camptonite. The magnesio-hastingstite macrocrysts have virtually the same composition as the matrix; they thus grew without much of a boundary layer. The magma crystallized in a disequilibrium way as a pseudo-unary system. The macrocrysts are unusually enriched in Fe3+ (approximately 44% of the total iron), yet locally enclose globules of immiscible sulfide melt. The magma became oxygenated owing to preferential loss of hydrogen upon the dissociation of aqueous gas bubbles. The amygdaloidal macrocrysts have a relatively high ?D value because of this loss of H2; the values of ?18O are typical of an upper mantle source. Camptonite dikes are very common on Mont Royal. Like the Lafarge dike, they likely arose by the disequilibrium crystallization of batches of the parental melt of asthenospheric origin.
DS1986-0007
1986
Alaska ReportAlaska ReportState's third diamond found northeast of FairbanksAlaska Report, Vol. 32, No. 39, sect. 1, October 1, p. 3AlaskaNews item, Diamonds notable
DS201810-2313
2018
Alatas, A.Finkelstein, G.J., Jackson, J.M., Said, A., Alatas, A., Leu, B.M., Sturhahn, W., Toellner, T.S.Strongly anisotropic magnesiowustite in Earth's lower mantle. Journal of Geophysical Research Solid Earth, doi.org/10.1029/ 2017JB015349Mantlecore mantle boundary

Abstract: The juxtaposition of a liquid iron?dominant alloy against a mixture of silicate and oxide minerals at Earth's core?mantle boundary is associated with a wide range of complex seismological features. One category of observed structures is ultralow?velocity zones, which are thought to correspond to either aggregates of partially molten material or solid, iron?enriched assemblages. We measured the phonon dispersion relations of (Mg,Fe) O magnesiowüstite containing 76 mol % FeO, a candidate ultralow?velocity zone phase, at high pressures using high?energy resolution inelastic X?ray scattering. From these measurements, we find that magnesiowüstite becomes strongly elastically anisotropic with increasing pressure, potentially contributing to a significant proportion of seismic anisotropy detected near the base of the mantle.
DS201607-1302
2016
Al-Attar, D.Hoggard, M.J., White, N., Al-Attar, D.Global dynamic topography observations reveal limited influences of large scale mantle flow.Nature Geoscience, Vol. 9, 6, pp. 456-463.MantleGeodynamics

Abstract: Convective circulation of the Earth’s mantle maintains some fraction of surface topography that varies with space and time. Most predictive models show that this dynamic topography has peak amplitudes of about ±2?km, dominated by wavelengths of 104?km. Here, we test these models against our comprehensive observational database of 2,120 spot measurements of dynamic topography that were determined by analysing oceanic seismic surveys. These accurate measurements have typical peak amplitudes of ±1?km and wavelengths of approximately 103?km, and are combined with limited continental constraints to generate a global spherical harmonic model, the robustness of which has been carefully tested and benchmarked. Our power spectral analysis reveals significant discrepancies between observed and predicted dynamic topography. At longer wavelengths (such as 104?km), observed dynamic topography has peak amplitudes of about ±500?m. At shorter wavelengths (such as 103?km), significant dynamic topography is still observed. We show that these discrepancies can be explained if short-wavelength dynamic topography is generated by temperature-driven density anomalies within a sub-plate asthenospheric channel. Stratigraphic observations from adjacent continental margins show that these dynamic topographic signals evolve quickly with time. More rapid temporal and spatial changes in vertical displacement of the Earth’s surface have direct consequences for fields as diverse as mantle flow, oceanic circulation and long-term climate change.
DS1997-0293
1997
Albarade, F.Duchene, S., Lardeaux, J.M., Albarade, F.Exhumation of eclogites: insights from depth time path analysisTectonophysics, Vol. 280, No. 1-2, Oct. 26, pp. 125-140.MantleEclogites, Subduction
DS1998-0047
1998
AlbaraedeArndt, N., Ginibre, C., Chauvel, Albaraede, CheadleWere komatiites wet?Geology, Vol. 26, No. 8, Aug. pp. 739-42GlobalMelting hydrous mantle, spiniflex textures, Magmatic volatiles
DS1998-0018
1998
Albaraede, F.Albaraede, F.The growth of continental crustTectonophysics, Vol. 296, No. 1-2, Oct. 30, pp. 1-15.MantleCraton, Magmatism
DS2003-0446
2003
Albaraede, F.Gasperini, D., Blichert Toft, J., Bosch, D., Del Moro, A., Macera, P., Albaraede, F.Upwelling of deep mantle material through a plate window: evidence from theJournal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001JB000418MantleGeophysics - seismics, Tectonics
DS200412-0614
2003
Albaraede, F.Gasperini, D., Blichert Toft, J., Bosch, D., Del Moro, A., Macera, P., Albaraede, F.Upwelling of deep mantle material through a plate window: evidence from the geochemistry of Italian basaltic volcanics.Journal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001 JB000418MantleGeophysics - seismics Tectonics
DS200712-0721
2007
Albaraede, F.Meyzen, C.M., Blichert-Toft, J., Ludden, J.N., Humler, E., Mevel, C., Albaraede, F.Isotopic portrayal of the Earth's upper mantle flow field.Nature, Vol. 447, June 28, pp.1069-1074.MantleGeochronology - subduction
DS200712-0722
2007
Albaraede, F.Meyzen, C.M., Blichert-Toft, J., Ludden, J.N., Humler, E., Mevel, C., Albaraede, F.Isotopic portrayal of the Earth's upper mantle flow field.Nature, Vol. 447, June 28, pp.1069-1074.MantleGeochronology - subduction
DS201112-0011
2011
Albaraede, F.Albaraede, F., Ballhaus, C., Lee, C.T.A., Yin, Q-Z., Blichert-Toft, J.The great volatile delivery to Earth.Goldschmidt Conference 2011, abstract p.420.MantleGeochronology - Pb
DS200712-0339
2007
Albarec, F.Gaffney, A.M., Blichert-Toft, J., Nelson, B.K., Bizzarro, M., Rosing, M., Albarec, F.Constraints on source forming processes of West Greenland kimberlites inferred from Hf Nd isotope systematics.Geochimica et Cosmochimica Acta, Vol. 71, 11, June 1, pp. 2820-2836.Europe, GreenlandGeochronology
DS1998-1540
1998
AlbaredeVervoort, J., Patchett, P.J., Blichert-Toft, AlbaredeHafnium neodymium isotopic covariance in the crust and mantle and constraints on the evolution of the depleted mantle.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1595-6.GreenlandGeochronology
DS201112-0053
2011
AlbaredeBallhaus, C., Laurenz, V., Fonseca, R., Munker, C., Albarede, Rohrbach, Schmidt, Jochum, Stoll, Weis, HelmyLate volatile addition to Earth.Goldschmidt Conference 2011, abstract p.475.MantleW and Cr elements
DS1989-0002
1989
Albarede, E.Abouchamy, W., Boher, M., Michard, A., Albarede, E., et al.Crustal growth in West Africa at 2.1 Ga: preliminary resultsEos, Vol. 70, No. 15, April 11, p. 485. (abstract.)West Africa, Mauritania, Senegal, Mali, Guinea, Ivory CoastGhana, Burkina Faso, Tectonics, Geochronology
DS1982-0004
1982
Albarede, F.Albarede, F., Weisbrod, A., Allegre, C.J.The Hercynian Lamprophyres of Southeastern Massif; Isotopic reequilibrium of Strontium and Neodynium in a Metamorphic Environment.C.n.r.s. Paris, PP. 11-12. (abstract.)GlobalGeochemistry, Geochronology
DS1982-0008
1982
Albarede, F.Alibert, C., Michard, A., Albarede, F.Strontium, Neodymium Isotopes and Trace Element Geochemistry of melilitites from Western Europe.Proceedings of Third International Kimberlite Conference, TERRA, Vol. 2, No. 3, PP. 213-214, (abstract.).GlobalKimberlite, Rare Earth Elements (ree)
DS1983-0007
1983
Albarede, F.Alibert, C., Michard, A., Albarede, F.The Transition from Alkali Basalts to Kimberlites Isotope And Trace Element Evidence from Melilitites.Contributions to Mineralogy and Petrology, Vol. 82, No. 2-3, PP. 176-186.GlobalPetrology, Petrography
DS1986-0013
1986
Albarede, F.Alibert, C., Michaud, A., Albarede, F.Isotope and trace element geochemistry of Colorado PLateau volcanicsGeochem. et Cosmochem. Acta, Vol.50, No. 12, December pp. 2735-2750ColoradoUSA, Geochemistry
DS1987-0004
1987
Albarede, F.Albarede, F., Brouxel, M.The Sm/neodymium secular evolution of the continental crust and the depletedmantleEarth and Planetary Science Letters, Vol. 82, No. 1/2, March pp. 25-35GlobalMantle, Genesis
DS1987-0101
1987
Albarede, F.Chaussidon, M., Albarede, F., Sheppard, S.M.F.Sulphur isotope heterogeneity in the mantle from ion microprobe measurements of sulphide inclusions in diamondsNature, Vol. 330, No. 6145, November 19, pp. 242-243GlobalBlank
DS1987-0102
1987
Albarede, F.Chaussidon, M., Albarede, F., Sheppard, S.M.F.Sulfur isotope compositions of sulfide inclusions from diamonds and megacrysts by ion microprobeEos, abstractSouth AfricaPetrology
DS1988-0005
1988
Albarede, F.Alibert, C., Albarede, F.Relationships between mineralogical, chemical and isotopic properties of some North American kimberlitesJournal of Geophysical Research, Vol. 93, No. B7, July 10, pp. 7643-7671Colorado, Wyoming, Kentucky, Pennsylvania, KansasArkansaw, Quebec, British Columbia, Lamproite, Alnoite, Kimberl
DS1989-0016
1989
Albarede, F.Albarede, F.Sm/neodymium constraints on the growth rate of continental crustTectonophysics, Vol. 161, No. 3/4, pp. 299-305GlobalGeochronology, Crust
DS1989-0248
1989
Albarede, F.Chaussidon, M., Albarede, F., Sheppard, S.M.F.Sulphur isotope variations in the mantle from ion microprobe analyses of micro-sulphide inclusionsEarth and Planetary Science Letters, Vol. 92, No. 2, pp. 144-156GlobalGeochemistry, Mantle -Kimberlite
DS1989-0249
1989
Albarede, F.Chaussidon, M., Albarede, F., Sheppard, S.M.F.Ion microprobe evidence for O34S variations in primary magmatic sulphides from diamonds, ultramafic and basic rocksJournal of the Geological Society of London, Vol. 146, pt. 2, July p. 660. AbstractGlobalGeochronology, Diamond inclusions -Sulph
DS1992-0011
1992
Albarede, F.Albarede, F.How deep do common basaltic magmas form and differentiateJournal of Geophysical Research, Vol. 97, No. B7, July 10, pp. 997-1009MantleBasaltic magmas, Differentiation
DS1992-0138
1992
Albarede, F.Boher, M., Abouchami, W., Michard, A., Albarede, F., Arndt, N.T.Crustal growth in West Africa at 2.1 GaJournal of Geophysical Research, Vol. 97, No. B1, January 10, pp. 345-369GlobalGeophysics, Craton
DS1994-0655
1994
Albarede, F.Grasset, O., Albarede, F.Hybridization of mingling magmas with different densitiesEarth and Planetary Science Letters, Vol. 121, No. 3-4, February pp. 327-332GlobalMagma generation
DS1995-0017
1995
Albarede, F.Albarede, F.Introduction to geochemical modelingCambridge University of press, 563p. approx. $ 200.00GlobalGeochemistry, Book -ad
DS1997-0104
1997
Albarede, F.Blichert-Toft, J., Albarede, F.The Lutetium - Hafnium isotope geochemistry of chondrite and the evolution of mantle crust systemEarth and Planetary Science Letters, Vol. 148, No. 1-2, Apr. 1, pp. 243-258MantleChondite, Geochemistry
DS1998-0019
1998
Albarede, F.Albarede, F.Time dependent models uranium, thorium, Helium, Potassium, Argon evolution and the layering of mantle convection.Chemical Geology, Vol. 145, No. 3-4, Apr. 15, pp. 413-430.MantleGeochronology
DS1999-0076
1999
Albarede, F.Blichert Toft, J., Albarede, F., Kornprobst, J.Lutetium - Hafnium isotope systematics of garnet pyroxenites from Beni Bousera: implications for basalt origin.Science, Vol. 285, No. 5406, Feb. 26, pp. 1303-5.MoroccoGeochronology, Deposit - Beni Bousera
DS1999-0179
1999
Albarede, F.Duchene, S., Albarede, F.Simulated garnet clinopyroxene geothermometry of eclogites #2Contributions to Mineralogy and Petrology, Vol. 135, No. 1, pp. 75-91.GlobalGeothermometry, Eclogites
DS2002-0016
2002
Albarede, F.Albarede, F., Van der Hilst, R.D.Zoned mantle convectionPhilosophical Transactions, Royal Society of London Series A Mathematical, Vol.1800, pp. 2569-92.MantleGeochemistry - model, convection
DS200412-0013
2004
Albarede, F.Albarede, F.High 3He 4He and solar Ne in OIB: should we wonder?Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A552.MantleConvection, models
DS200412-0123
2004
Albarede, F.Bedini, R.M., Blichert-Toft, J., Boyet, M., Albarede, F.Isotopic constraints on the cooling of the continental lithosphere.Earth and Planetary Science Letters, Vol. 223, 1-2, June, 30, pp. 99-111.Africa, South AfricaGarnet peridotite xenoliths, radiometric ages, geotherm
DS200612-0010
2005
Albarede, F.Albarede, F.The survival of mantle geochemical heterogeneities.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 27-46.MantleGeochemistry
DS200612-0011
2005
Albarede, F.Albarede, F.Helium feels the heat in Earth's mantle.Science, No. 5755, Dec. 16, p. 1777.MantleGeophysics
DS200612-0012
2006
Albarede, F.Albarede, F., Blichert-Toft, J.Reading old mantle tea leaves: the survival of plate material in the source of MORB and OIB.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 7, abstract only.MantleGeochronology
DS200612-0118
2006
Albarede, F.Ben Othman, D., Luck, J.M., Bodinier, J.L., Arndt, N.T., Albarede, F.Cu Zn isotopic variations in the Earth's mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleGeochemistry
DS200612-0486
2006
Albarede, F.Graham, D.W., Blichert Toft, J., Russo, C.J., Rubin, K.H., Albarede, F.Cryptic striations in the upper mantle revealed by hafnium isotopes in southeast Indian Ridge basalts.Nature, Vol. 440, 7081, pp. 199-202.Asia, IndiaGeochronology, tectonics
DS200612-0540
2005
Albarede, F.Harrison, T.M., Blichert-Toft, J., Muller, W., Albarede, F., Holden, P., Mojzsis, S.J.Heterogeneous Hadean hafnium: evidence of continental crust 4.4 to 4.5 Ga.Science, Vol. 310, 5736 Dec. 23, pp. 1947-1949.MantleGeochronology
DS200612-0541
2006
Albarede, F.Harrison, T.M., McCulloch, M.T., Blichert-Toft, J., Albarede, F., Holden, P., Mojzsis, S.J.Further Hf isotope evidence for Hadean continental crust.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 14, abstract only.MantleGeochronology
DS200712-0083
2007
Albarede, F.Blichert-Toft, J., Harrison, T.M., Albarede, F.The age of the earliest continental crust and onset of plate tectonics.Plates, Plumes, and Paradigms, 1p. abstract p. A98.AustraliaGeochronology
DS200712-0340
2007
Albarede, F.Gaffney, A.M., Blichert-Toft, J., Nelson, B.K., Bizzarro, M., Rosing, M., Albarede, F.Constraints on source forming processes of West Greenland kimberlites inferred from Hf Nd isotope systematics.Geochimica et Cosmochimica Acta, Vol. 71, 11, pp. 2820-2836.Europe, GreenlandDiamond genesis
DS200812-0012
2008
Albarede, F.Albarede, F.The physics of mantle geochemical heterogeneities.Goldschmidt Conference 2008, Abstract p.A14.MantleFluid dynamics
DS200812-0013
2008
Albarede, F.Albarede, F.Rogue mantle helium and neon.Science, Vol. 319, No. 5865, pp. 943-945.MantleIsotope geochemistry
DS200812-0014
2008
Albarede, F.Albarede, F., Blichert-Tor, J.The Earth accredited dry and its ocean rains into the mantle.Goldschmidt Conference 2008, Abstract p.A15.MantleWater
DS200812-0118
2008
Albarede, F.Blichert-Toft, J., Albarede, F.Hafnium isotopes in Jack Hills zircons and the formation of the Hafnium crust.Earth and Planetary Science Letters, Vol. 265, 3-4, Jan. 30, pp. 686-702.AustraliaGeochronology
DS201012-0315
2010
Albarede, F.Iwamori, H., Albarede, F., Nakamura, H.Global structure of mantle isotopic heterogeneity and its implications for mantle differentiation and convection.Earth and Planetary Science Letters, Vol. 299, 3-4, pp. 339-351.MantleConvection
DS201312-0053
2013
Albarede, F.Ballhaus, C., Laurenz, V., Munker, C., Fonseca, R.O.C., Albarede, F., Rohrbach, A., Lagos, M., Schmidt, M.W., Jochum, K-P., Stoll, B., Weis, U., Helmy, H.M.The U /Pb ratio of the Earth's mantle - a signature of late volatile addition.Earth and Planetary Interiors, Vol. 362, pp. 237-245.MantleMelting
DS201412-0310
2014
Albarede, F.Graham, D.W., Hanan, B.B., Hemond, C., Blichert-Toft, J., Albarede, F.Helium isotopic textures in Earth's upper mantle.Geochemistry, Geophysics, Geosystems: G3, Vol. 15, no. 5, pp. 2048-2074.MantleHelium
DS2002-0064
2002
Albaredem, F.Arndt, N.T., Lewin, E., Albaredem, F.Strange partners: formation and survival of continental crust and lithospheric mantleGeological Society of London Special Publication, No. 199, pp. 91-104.MantleTectonics
DS1983-0006
1983
Albaredo, F.Alibert, C., Albaredo, F.Isotopic Heterogeneities in North American KimberlitesEos, Vol. 64, No. 18, MAY 3, P. 341. (abstract.).United StatesBlank
DS200812-0636
2008
AlbaricLe Gall, B., Nonnotte, P., Rolet, J., Benoit, M., Guillou, H., Mousseau Nonnotte, M., Albaric, DeverchreRift propogation at craton margin: distribution of faulting and volcanism in the north Tanzanian divergence ( East Africa) during Neogene times.Tectonophysics, Vol. 448, 1-4, pp. 1-19.Africa, TanzaniaMagmatism
DS1970-0003
1970
Albee, A.I.Albee, A.I., Ray, L.Correction Factors for Electron Probe Microanalysis of Silicates, Oxides, Carbonates, Phosphates and Sulfates.Anal. Chem., Vol. 42, No. 12, OCTOBER, PP. 1408-1414.GlobalMicroprobe, Analyses
DS1960-0921
1968
Albee, A.L.Bence, A.E., Albee, A.L.Empirical Correction Factors for the Electron Microanalysis of Silicates and Oxides.Journal of Geology, Vol. 76, PP. 382-403.GlobalMicroprobe
DS1950-0509
1959
Albee, H.F.Stuart, J.H., Williams, G.A., Albee, H.F., Raup, O.B.Stratigraphy of Triassic and Associated Formations in Part Of the Colorado Plateau Region with a Section on Sedimentarypetrology.United States Geological Survey (USGS) Bulletin., No. 1046-Q, PP. 487-576.Colorado PlateauKimberlite, Rocky Mountains
DS201706-1061
2017
Albekov, A.Yu.Albekov, A.Yu., Chemyshov, N.M., Ryborak, M.V., Kuznetsov, V.S., Sainikova, E.B., Kholin, V.M.U-Pb isotopic age of apatite bearing carbonatites in the Kursk Block, Voronezh crystalline massif ( Central Russia).Doklady Earth Sciences, Vol. 473, 1, pp. 271-272.Russiacarbonatite

Abstract: In the central part of the European part of Russia in the southeastern part of the Kursk tectonic block, some deposits and occurrences of apatite genetically related to the alkaline-carbonatite complex have been revealed. The results of U-Pb analysis of titanite provided the first confident age estimate of silicate-carbonate (phoscorite) rocks in the Dubravin alkaline-ultramafic-carbonatite massif: they formed no later than 2080 ±13 Ma, which indicates their crystallization in the pre-Oskol time during the final stage of the Early Paleoproterozoic (post-Kursk time) stabilization phase of the Kursk block of Sarmatia (about 2.3-2.1 Ga).
DS1995-0018
1995
Alberdi, M.Alberdi, M., Contreras, G.Estratigraffia del Grupo Roraima e interpretacion petrologica en la region del Noreste Canaima.U.s. Geological Survey Bulletin., No. 2124-A, Chapter I.Venezuela, BolivarStratigraphy, petrology, Roraima Group
DS201706-1062
2017
Albers, G.A.Albers, G.A., van Keken, P.E., Hacker, B.R.The cold and relatively dry nature of mantle forearcs in subduction zones.Nature Geoscience, Vol. 10, 5, pp. 333-337.Mantlesubduction

Abstract: Some of Earth's coldest mantle is found in subduction zones at the tip of the mantle wedge that lies between the subducting and overriding plates. This forearc mantle is isolated from the flow of hot material beneath the volcanic arc, and so is inferred to reach temperatures no more than 600 to 800 °C — conditions at which hydrous mantle minerals should be stable. The forearc mantle could therefore constitute a significant reservoir for water if sufficient water is released from the subducting slab into the mantle wedge. Such a reservoir could hydrate the plate interface and has been invoked to aid the genesis of megathrust earthquakes and slow slip events. Our synthesis of results from thermal models that simulate the conditions for subduction zones globally, however, indicates that dehydration of subducting plates is too slow over the life span of a typical subduction zone to hydrate the forearc mantle. Hot subduction zones, where slabs dehydrate rapidly, are an exception. The hottest, most buoyant forearcs are most likely to survive plate collisions and be exhumed to the surface, so probably dominate the metamorphic rock record. Analysis of global seismic data confirms the generally dry nature of mantle forearcs. We conclude that many subduction zones probably liberate insufficient water to hydrate the shallower plate boundary where great earthquakes and slow slip events nucleate. Thus, we suggest that it is solid-state processes and not hydration that leads to weakening of the plate interface in cold subduction zones.
DS1996-0012
1996
Albers, M.Albers, M., Christensen, U.R.The excess temperature of plumes rising from the core-mantle boundaryGeophysical Research. Letters, Vol. 23, No. 24, Dec. 1, pp. 3567-70.MantlePlumes, Hotspots
DS202203-0354
2022
Albers. C.Krstulovic, M., Rosa, A.D., Sanchez, D.F., Libon, L., Albers. C., Merkulova, M., Grolimund, D., Irifune, T., Wilke, M.Effect of temperature on the densification of silicate melts to lower Earth's mantle.Physics of the Earth and Planetary Interiora, 13p. PdfMantlemelting

Abstract: Physical properties of silicate melts play a key role for global planetary dynamics, controlling for example volcanic eruption styles, mantle convection and elemental cycling in the deep Earth. They are significantly modified by structural changes at the atomic scale due to external parameters such as pressure and temperature or due to chemistry. Structural rearrangements such as 4- to 6-fold coordination change of Si with increasing depth may profoundly influence melt properties, but have so far mostly been studied at ambient temperature due to experimental difficulties. In order to investigate the structural properties of silicate melts and their densification mechanisms at conditions relevant to the deep Earth's interior, we studied haplo basaltic glasses and melts (albite-diopside composition) at high pressure and temperature conditions in resistively and laser-heated diamond anvil cells using X-ray absorption near edge structure spectroscopy. Samples were doped with 10 wt of Ge, which is accessible with this experimental technique and which commonly serves as a structural analogue for the network forming cation Si. We acquired spectra on the Ge K edge up to 48 GPa and 5000 K and derived the average Ge-O coordination number , and bond distance as functions of pressure. Our results demonstrate a continuous transformation from tetrahedral to octahedral coordination between ca. 5 and 30 GPa at ambient temperature. Above 1600 K the data reveal a reduction of the pressure needed to complete conversion to octahedral coordination by ca. 30 . The results allow us to determine the influence of temperature on the Si coordination number changes in natural melts in the Earth's interior. We propose that the complete transition to octahedral coordination in basaltic melts is reached at about 40 GPa, corresponding to a depth of ca. 1200 km in the uppermost lower mantle. At the core-mantle boundary (2900 km, 130 GPa, 3000 K) the existence of non-buoyant melts has been proposed to explain observed low seismic wave velocity features. Our results highlight that the melt composition can affect the melt density at such extreme conditions and may strongly influence the structural response.
DS2001-0907
2001
AlbertPereira, F., Bilal, E., Moutte, Lapido, Gruffat, AlbertDissolution of apatite ore from Angico Dos Dias carbonatite Complex and recovery of rare earth elementsJournal of South African Earth Sciences, Vol. 32, No. 1, p. A 28.(abs)BrazilCarbonatite, Angico Dos Dias
DS1984-0485
1984
Albert, G.K.Marrs, R.W., Marks, J.E., Hausel, W.D., Albert, G.K.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Province. #1International Symposium on Remote Sensing of Environment., THIRD THEMATIC CONFERENCE, APRIL 16TH.-19TH. 11P.United States, State Line, Colorado, WyomingLandsat, Remote Sensing, Geophysics, Analyses, Diatreme
DS1982-0264
1982
Albert, K.Hausel, W.D., Albert, K., Brink, C., Roberts, J.Report on Investigations Related to Prospecting for Diamond bearing Kimberlite and Related Placer Deposits in Wyoming.Wyoming Geological Survey Open File Report, No. 82-1, 48P.United States, Wyoming, State Line, Rocky Mountains, Green River BasinGeochemistry, Prospecting
DS1983-0150
1983
Albert, K.C.Brink, C., Albert, K.C., Hausel, W.D.Stream Sediment Sampling for Kimberlite in Colorado-wyoming, and Techniques of Diamond Extraction.Wyoming Geological Survey Public Inf. Circular, No. 19, PP. 40-41.United States, State Line, Colorado, WyomingProspecting, Sampling
DS1983-0294
1983
Albert, K.G.Hausel, W.D., Albert, K.G.A Review of the Geology, Exploration Methods and Diamond Extraction Techniques of Colorado and Wyoming Kimberlites.American Mining Congress Meeting Held San Francisco, Sept. 1, EXPLORATION and TECHNOLOGY SESSION, SEPT. 14TH. 6P.United States, Colorado, Wyoming, State Line, Rocky MountainsMining Engineering, Geology, Prospecting, Evaluation, Sampling
DS1984-0484
1984
Albert, K.G.Marrs, R.W., Marks, J., Hausel, W.D., Albert, K.G.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Province. #2Nasa Jet Propulsion Laboratory, Final Report Dated Sept. 28t, 70P.United States, Colorado, Wyoming, State Line, Rocky MountainsRemote Sensing, Geochemistry, Sampling, Prospecting, Geophysics
DS200612-1014
2006
Albert, R.O'Neill, C., Moresi, L., Muller, D., Albert, R., Dufour, F.Ellipse 3D: a particle in cell finite element hybrid code for modelling mantle convection and lithosphere deformation.Computers & Geosciences, Vol. 32, 10, pp. 1769-1779.TechnologyComputer program - convection model
DS1999-0007
1999
Alberta - Rock ChipsAlberta - Rock ChipsKimberlitic diatremes reported in three separate areas of Alberta. Birch Mountains recent discovery.Alberta - Rock Chips, Winter 98/99, p. 3.AlbertaNews item, Birch Mountains
DS2002-0017
2002
Alberta Geological SurveyAlberta Geological SurveyStructural emplacement model for kimberlite diatremes in northern AlbertaAlberta Geological Survey, www.ags.gov.ab.ca, ESR 2000-01, 345MB pdf $ 20.AlbertaStructure
DS2002-0018
2002
Alberta Geological SurveyAlberta Geological Survey2002 compilation of Alberta ultramafic rock occurrences: location, ground geophysics, drill hole logs and diamond content.Alberta Geological Survey, [email protected], Geo-Note 2002-23.AlbertaBlank
DS2003-0006
2003
Alberta Geological SurveyAlberta Geological SurveyRadiogenic isotope geochemistry of kimberlitic rocks in northern Alberta: constraintsAlberta Geological Survey, [email protected], Geo-Note 2003-7AlbertaBlank
DS200412-0014
2003
Alberta Geological SurveyAlberta Geological SurveyRadiogenic isotope geochemistry of kimberlitic rocks in northern Alberta: constraints for source magmatism and emplacement age.Alberta Geological Survey, Geo-Note 2003-7,Canada, AlbertaGeochemistry, geochronology
DS200412-0015
2002
Alberta Geological SurveyAlberta Geological Survey2002 compilation of Alberta ultramafic rock occurrences: location, ground geophysics, drill hole logs and diamond content.Alberta Geological Survey, Geo-Note 2002-23.Canada, AlbertaGeochemistry, geophysics
DS1993-0020
1993
Alberti, A.Alberti, A., Alessandro, V., Pieruccini, U., Pranzini, E.Land sat Thematic Mapperdat a processing for lithological discrimination in the Caraculoarea (Namibe Province, southwest Angola).Journal of African Earth Sciences, Vol. 17, No. 3, October pp. 261-274.AngolaLandsat -not specific to diamonds, Remote sensing, lithology
DS1999-0008
1999
Alberti, A.Alberti, A., Castorina, Censi, Comin-Chiaramonti, GomesGeochemical characteristics of Cretaceous carbonatites from AngolaJournal of African Earth Sciences, Vol. 29, No. 4, Dec. pp. 735-59.AngolaCarbonatite, geochemistry, Parana-Angola, Etendeka Province
DS201908-1768
2019
Alberti, M.Alberti, M., Arabas, A., Fursich, F.T., Andersen, N., Ziolkowski, P.The Middle to Upper Jurassic stable isotope record of Madagascar: linking temperature changes with plate tectonics during the break-up of Gondwana.Gondwana Research, Vol. 73, pp. 1-15.Africa, Madagascargeochemistry

Abstract: Stable isotope (?18O, ?13C) analyses were performed on well preserved belemnites, oysters, and rhynchonellid brachiopods from the Middle to Upper Jurassic of the Morondava Basin in southern Madagascar. Both brachiopods and oysters indicate similar average temperatures of 18.7 to 19.3?°C in the Early Callovian, followed by a temperature decrease towards the Middle Oxfordian (13.9?°C) and a minimum in the Early Kimmeridgian (12.3?°C). In contrast, belemnites from the Oxfordian show lower average temperatures of 10.0?°C, which is likely caused by specific conditions for these organisms (e.g., different fractionation or life habits). Additionally, three oysters from the Upper Oxfordian and Lower Kimmeridgian were used for high-resolution stable isotope analyses. The data show seasonal fluctuations of >6?°C around averages between 14.4 and 14.7?°C. Latitudinal temperature gradients for the Callovian and Kimmeridgian are similar to today at the examined low latitudes of the southern hemisphere. The observed cooling of around 5?°C from the Callovian to the Oxfordian/Kimmeridgian can be attributed to a concurrent southward drift of Madagascar during the break-up of Gondwana. Thus, the study underlines the importance of considering palaeogeography in interpreting stable isotope data as well as the potential of detecting and timing palaeogeographic events by using stable isotope analyses.
DS1960-0774
1967
Albertus MagnusAlbertus MagnusBook of Minerals (translated by D. Wyckoff)Oxford: Clarendon., 310P. (DIAMOND PP. 70-71; P. 133; P. 148.), XEROX.GlobalKimberley, Gemology, Janlib, Kimberlite
DS2001-0540
2001
Albertz, M.Johnson, S.E., Albertz, M., Paterson, S.R.Growth rates of dike fed plutons: are they compatible with observations In the middle and upper crust?Geology, Vol. 29, No. 8, Aug. pp. 727-30.MantleDikes, diapirs, plutons
DS1989-0017
1989
Albin, S.Albin, S., Watkins, L., Ravi, K., Yokota, S.Diamond films for laser hardeningAppl. Phys. Letters, Vol. 54, No. 26, June 26, pp. 2728-2730GlobalDiamond filM., Synthetic diamonds
DS1988-0411
1988
Albon, S.D.Leader-Williams, N., Albon, S.D.Allocation of resources for conservationNature, Vol. 336, Dec. 8, pp. 533-535. Database # 17545GlobalEnvironmental issue, Economics
DS201212-0008
2012
Alboussiere, T.Alboussiere, T., Deguen, R.Asymmetric dynamics of the inner core and impact on the outer core.Journal of Geodynamics, Vol. 61, pp. 172-182.MantleTectonics
DS1990-1545
1990
Al-Boutiahl, F.H.M.Watkins, A.J., Al-Boutiahl, F.H.M.On maximum likelihood estimation of parameters in incorrectly specified models of covariance for spatialdataMathematical Geology, Vol. 22, No. 2, pp. 151-173GlobalGeostatistics, Statistical inference
DS1982-0005
1982
Albouy, J.Albouy, J., Godivier, R.Gravimetric Maps of the Central African RepublicNational Technical Information Service, NASA CR 169596, 14P.GlobalBouguer, Gravity, Geophysics
DS1988-0070
1988
Albouy, Y.Bonvalot, S., Villeneurve, M., Legeley, A., Albouy, Y.Leve gravimetrique du sud-ouest du craton Ouest -Africain.(in French)C.r. Academy Of Science Paris, Vol. 307, ser. II, pp. 1863-1868GlobalGeophysics-gravity, Tectonics
DS1989-1555
1989
Albouy, Y.Vicat, J-P., Gioan, P., Albouy, Y., Cornacchia, M., Giorgi, L.Evidence of Upper Proterozoic rifts buried under the Phanerozoic of the Zaire basin on the western border of the Congo craton.(in French)Comptes Rendus, (in French), Vol. 309, No. 11, pp. 1207-1214Democratic Republic of CongoTectonics, Craton
DS1991-0148
1991
Albouy, Y.Bonvalot, S., Villeneuve, M., Albouy, Y.Gravity dat a interpretation in Sierra Leone- evidence of collision suture in the Rokelides Pan-African orogenic belt.(in French)Comptes Rendus de l'Academie des Sciences Serie II, Vol. 312, No. 8, April pp. 841-848Sierra LeoneGeophysics -gravity, Tectonics
DS1990-0108
1990
Albrecht, A.Albrecht, A., Knittel, U.The petrology of the Potassium rich alkaline rocks in the Palali Mountains(northern Luzon, Philippine island arc)Neues Jahrbuch f?r Mineralogie Abh, Vol. 161, No. 3, pp. 255-286GlobalAlkaline rocks, Potassium, Petrology
DS201901-0022
2018
Albrecht, R.Cordani, U.G., Ernesto, M., Da Silva Dias, M.A.F., de Alkmim, F.F., Medonca, C.A., Albrecht, R.Un pouco de historia: as Ciencias da Terra no Brasil colonial e no Imperio. ( IN PORT) History of Brazil gold and diamondsEstudos Avancados ( Ensino de Geosciencias na universidade), Vol. 32, (94), pp. 309-330. pdf available in PORT.South America, Brazilhistory
DS1991-0009
1991
Albrektsen, B.A.Albrektsen, B.A., Furnes, H., Pedersen, R.B.Formation of dunites in mantle tectonites, Leka ophiolite complex, SOURCE[ Journal of GeodynamicsJournal of Geodynamics, Vol. 13, No. 2-4, pp. 205-220NorwayOphiolite, Dunites
DS1991-0010
1991
Albrektsen, B.A.Albrektsen, B.A., Furnes, H., Pedersen, R.B.Formation of dunites in mantle tectonites, Leka ophiolite complex NorwayJournal of Geodynamics, Vol. 13, No. 2-4, pp. 205-220NorwayTectonics, Mantle -dunites
DS200712-0007
2006
Albright, M.K.Albright, M.K.Opportunities and Danger.. The world in 2006.Gems & Gemology, Vol. 42, 3, Fall, pp. 2-6.GlobalNews item - history
DS1989-0018
1989
Albritton, C.C.Albritton, C.C.Catastrophic episodes in earth historyChapman and Hall, 196p. $ 29.95GlobalBook -ad, Catastrophic episodes
DS200812-0787
2008
Al-BuaidiNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiEvolved carbonatitic kimberlite from the Batain Nappes, eastern Oman continental margin.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS200812-0788
2008
Al-BuaidiNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiLate Jurassic Early Cretaceous kimberlite, carbonatite and ultramafic lamprophyric sill and dyke swarms from the Bomethra area, northeastern Oman.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS201312-0036
2013
Albuquerque, D.F.Assumpcao, M., Bianchi, M., Julia, J., Dias, F.L., Nascimento, R., Drouet, S., Pavao, C.G., Albuquerque, D.F., Lopes, A.E.V.Crustal thickness map of Brazil: dat a compilation and main features.Journal of South American Earth Sciences, Vol. 609, pp. 82-96.South America, BrazilMOHO map
DS1994-0032
1994
Albuquerque, H.Albuquerque, H.Hydrothermal geochemistry of the Fire sand River carbonatite, OntarioMsc. Thesis, University Of Windsor, OntarioCarbonatite, Deposit -Firesand River
DS1997-0017
1997
Alcaston Mining NLAlcaston Mining NLAlcaston enlists help for battle in SwedenAlcaston Mining Nl., June 24, 1p.SwedenNews item - press release, Poplar Resources Ltd.
DS1982-0139
1982
Alcoa of australia lts, WESTERN MINING CORP. LTD.Chuck, R.G., Alcoa of australia lts, WESTERN MINING CORP. LTD.El 2654 Mt. Skinner Central Australia Base Metal Exploration Final Report 1981-982..Northern Territory Geological Survey Open File Report, No. CR 83/125, A, B, 45P.Australia, Northern TerritoryProspecting, Geophysics, Photogeology
DS1960-0621
1966
Alcolea, S.Alcolea, S.DiamantesBiblioteca Nacional, 18P.GlobalKimberlite, Diamond
DS1989-0019
1989
Alcover Neto, A.Alcover Neto, A., Toledo-Groke, M.C.Preliminary characterization of the supergene evolution of the carbonatite rocks of the Juquia (sp) Alkaline carbonatite complex with phosphateenrichmentXiii International Geochemical Exploration Symposium, Rio 89 Brazilian, p. 219. AbstractBrazilCarbonatite, Geochemistry
DS200512-0009
2005
Aldanmaz, E.Aldanmaz, E., Gourgaud, A., Kaymakc, N.Constraints on the composition and thermal structure of the upper mantle under NW Turkey: evidence from mantle xenoliths and alkali primary melts.Journal of Geodynamics, Vol. 39,3, April pp. 277-316.Europe, TurkeySpinel-lherzolites, geothermometry, xenoliths upper mantle
DS1910-0550
1918
Alden, W.C.Alden, W.C.The Quaternary Geology of South Eastern WisconsinUnited States Geological Survey (USGS) PROF. PAPER., No. 106, P. 221; P. 259; P. 270; P. 301; P. 308.United States, Great Lakes, WisconsinGeomorphology
DS1992-0012
1992
Aldhous, P.Aldhous, P.Making buckyballs go ballisticScience, Vol. 257, September 11, p. 1481GlobalBuckyballs, carbon60, Fullerenes
DS1991-0011
1991
Aldiss, D.T.Aldiss, D.T.The Motloutse Complex and the Zimbabwe Craton/Limpopo Belt transition inBotswanaPrecambrian Research, Vol. 50, No. 1-2, April pp. 89-110BotswanaCraton
DS1960-0746
1966
Aldrich, L.T.Smith, T.J., Steinhart, L.S., Aldrich, L.T.Crustal Structure Under Lake SuperiorAmerican GEOPHYSICAL MONOGRAPH, No. 10, PP. 181-197.Michigan, WisconsinMid-continent
DS1981-0003
1981
Aldrich, M.J.Aldrich, M.J., Ander, M.E., Laughlin, A.W.Geological and Geophysical Signatures of the Jemez Lineament: a Reactivated Precambrian Structure.National Technical Information Service LA-UR-82-561, Conference 8L0887-2, DE82011971, 35P.GlobalMid-continent, Tectonic
DS1986-0486
1986
Aldrich, M.J.Laughlin, A.W., Charles, R.W., Aldrich, M.J.Heteromorphism and crystallization paths of katungites, Navajo volcanic field Arizona, USAProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 187-189ArizonaBlank
DS1986-0008
1986
Aldrich, M.J. Jr.Aldrich, M.J. Jr., Laughlin, A.W.Proceedings of the Sixth International Conference on Basement Tectonics, held Santa Fe Sept. 1985International Basement Tectonics Publ, 210pGlobalTectonics
DS1984-0005
1984
Aldrich, M.J.JR.Aldrich, M.J.JR., Laughlin, A.W.A Model for the Tectonic Development of the Southeastern Colorado Plateau Boundary.Journal of Geophysical Research, Vol. 89, No. B12, PP. 10, 207-10218.United States, Colorado PlateauTectonics
DS1985-0384
1985
Aldrich, M.J.JR.Laughlin, A.W., Aldrich, M.J.JR., Shafiqullah, M., Husler, J.Tectonic implications of the age, composition and orientation of lamprophyric dikes, Navajo volcanic fieldEarth and Planetary Science Letters, Vol. 76, pp. 361-374Colorado Plateau, ArizonaKatungite, Minette Potassium Metasomatism, Tectonic
DS1986-0485
1986
Aldrich, M.J.Jr.Laughlin, A.W., Aldrich, M.J.Jr., Shafiqulla, M., Husler, J.Comments on tectonic implications of the age, composition and orientation of lamprophyre dikes, Navajo Volcanic field,Arizona #1Earth and Planetary Science Letters, Vol. 80, No. 3-4, November pp. 415-417ArizonaTectonics, Dikes
DS1987-0562
1987
Aleinikoff, J.N.Pallister, J.S., Aleinikoff, J.N.Gabbroic plutons south of the Cheyenne belt: underpinnings of an early Proterozoic continental margin arcGeological Society of America, Vol. 19, p. 325. abstract onlyUnited StatesTectonics
DS1987-0608
1987
Aleinikoff, J.N.Reed, J.C.Jr, Bickford, M.E., Premo, W.R., Aleinikoff, J.N.Evolution of the early Proterozoic Colorado province:constraints from uranium-lead (U-Pb) (U-Pb) geochronologyGeology, Vol. 15, No. 9, September pp. 861-865United States, Colorado, WyomingGeochronology
DS1990-0109
1990
Aleinikoff, J.N.Aleinikoff, J.N., Winegarden, D.L., Walter, M.uranium-lead (U-Pb) (U-Pb) ages of zircon rims: a new analytical method using the air-abrasiontechniqueChemical Geology, Vol. 80, pp. 351-363GlobalGeochronology, Age determinations -uranium-lead (U-Pb) (U-Pb)
DS1993-0021
1993
Aleinikoff, J.N.Aleinikoff, J.N., Reed, J.C.Jr., Wooden, J.L.Lead isotope evidence for the origin of Paleo- and Mesoproterozoic rocks Of the Colorado Province, United States (US)Precambrian Research, Vol. 63, No. 1-2, September pp. 98-122ColoradoGeochronology
DS1983-0004
1983
Aleksandrov, et al.Aleksandrov, et al.Activation analysis of distribution of Silicon, copper, Manganese, Sodium, Cobalt impurities indiamond.(Russian)Cryst. Res. Tech., (Russian), No. 17, pp. 1389-1391RussiaRef. Fleischer United States Geological Survey (usgs) Of 88
DS200412-0078
2004
Aleksandrov, I.A.Avchenko, O.V., Lavrik, S.N., Aleksandrov, I.A., Velivetskaya, T.A.Isotopic heterogeneity of carbon in metamorphic fluid.Doklady Earth Sciences, Vol. 394, 1, pp. 81-84.Russia, Aldan ShieldMetamorphism, petrology
DS202010-1865
2020
Alekseenko, A.V.Pashkevich, M.A., Alekseenko, A.V.Reutilization prospects of diamond clay tailings at the Lomonosov mine, northwestern Russia.Minerals, Vol. 10, 517 10.3390/min10060517 17p. PdfRussiadeposit - Lomonosov

Abstract: Approaches to reutilization of diamond clay tailings in northern environments are considered in the example of the Subarctic region of Russia. The monitoring studies are conducted at storage facilities of Severalmaz PJSC where ca. 14 million cubic meters of waste rock are produced annually after kimberlite mining and processing. The tailings of diamond ore dressing waste are situated in complex geological conditions of high-groundwater influx and harsh cold climate with low levels of solar radiation and the average annual temperature below freezing point. Furthermore, the adjoining protected forests with a significant diversity of biogeocenoses and salmon-spawning rivers are affected by the storage area. Reducing the impact of the tailings can be achieved through the reuse of the stored clay magnesia rocks obtained from saponite-containing suspension. The experiments reveal the most promising ways of their application as potential secondary mineral raw materials: cement clinker and ceramics manufacture, integration of alkaline clay into the reclamation of acidic peat bogs, and production of aqueous clay-based drilling fluid. Field and laboratory tests expose the advantages and prospects of each suggested treatment technique.
DS2000-0012
2000
Alekseev, A.A.Alekseev, A.A., Alekseeva, G.V.Graphite eclogite from the Maksyutovo metamorphic complex, southern UralsDoklady Academy of Sciences, Vol. 372, No. 4, May-June pp. 669-71.Russia, UralsEclogite, Metamorphic Complex
DS201312-0917
2013
Alekseev, A.S.Tolmacheva, T.Yu., Alekseev, A.S., Reimers, A.N.Conodonts in xenoliths from kimberlite pipes of the southeastern White Sea region ( Arkhangelsk Oblast): key to Ordovician stratigraphic and paleogeographic reconstructions of the East European Platform.Doklady Earth Sciences, Vol. 451, 1, pp. 687-691.Russia, Archangel, Kola PeninsulaGeochronology
DS200412-0016
2004
Alekseev, N.L.Alekseev, N.L., Balagansky, V.V., Zinger, T.F., Levchenkov, O.A.Late Archean evolution of the junction between the Belomorian mobile belt and Karelian craton, Baltic Shield: evidence from newDoklady Earth Sciences, Vol. 397, 6, July-August pp. 743-746.Russia, Baltic ShieldGeochronology, tectonics
DS1996-0013
1996
Alekseev, S.G.Alekseev, S.G., Dukhanin, A.S., Veshev, S.A., Voroshilov, N.A.Some aspects of practical use of geoelectrochemical methods of exploration for deep seated mineralizationJournal of Geochem. Explor, Vol. 56, No. 1, June, pp. 79-86RussiaGeochemical exploration, Mineralization -at depth
DS2000-0012
2000
Alekseeva, G.V.Alekseev, A.A., Alekseeva, G.V.Graphite eclogite from the Maksyutovo metamorphic complex, southern UralsDoklady Academy of Sciences, Vol. 372, No. 4, May-June pp. 669-71.Russia, UralsEclogite, Metamorphic Complex
DS1982-0006
1982
Alekseyev, YU.A.Alekseyev, YU.A.Carbonatites of the Murun Ultrapotassic Alkaline Complex Northwestern Area of the Aldan Shield.Soviet Geology and GEOPHYS., Vol. 23, No. 9, PP. 55-60.Russia, AldanRelated Rocks
DS1984-0006
1984
Alekseyev, YU.A.Alekseyev, YU.A.Mineralogy of the Murun Complex Potassic-alkalic Rocks and CarbonatitesSovetsk. Geol., No. 5, PP. 46-51.RussiaMineralogy
DS1985-0004
1985
Alekseyev, YU.A.Alekseyev, YU.A.Geology of a New Charoite Type of Carbonatite and Associated Rocks.Doklady Academy of Science USSR, Earth Science Section., Vol. 272, No. 1-6, MARCH PP. 134-137.RussiaCarbonatite
DS1975-1167
1979
Alekseyevskiy, K.M.Nikolayeva, T.T., Alekseyevskiy, K.M.Typomorphic Features of Pyrope from North TimanAkad. Nauk Ssr, Geol. Ser., No. 11, PP. 131-135.RussiaGarnet, Analyses
DS1980-0005
1980
Alekseyevskiy, K.M.Alekseyevskiy, K.M., Nikolayeva, T.T., et al.Pyrope and Chromium Diopside from the Onega PeninsulaIzvest. Akad. Nauk Sssr, Geol. Ser., Vol. 1980, No. 5, PP. 85-92.RussiaBlank
DS1990-0110
1990
Alekseyevskiy, K.M.Alekseyevskiy, K.M.Prospecting significance of Takatin series analogs in Timan. (Russian)Razvedka I Okhrana Nedr., (Russian), 1990, No. 2, pp. 9-11RussiaDiamonds, Alluvials -placers
DS2001-0187
2001
Alem, E.M.Chorowicz, J., Emran, A., Alem, E.M.Tectonique et venues volcaniques en contexte de collision exemple du Massif neogene du Siroua...Canadian Journal of Earth Sciences, Vol. 38, No. 3, Mar. pp. 411-25.GlobalTectonics - panafricaine suture
DS201906-1266
2019
Alemayehu, M.Alemayehu, M., Guo, F., Aulbach, S.Transformation of continental lithospheric mantle beneath the East African Rift: constraints from platinum group elements and Re-Os isotopes in mantle xenoliths from Ethiopia.Contributions to Mineralogy and Petrology, Vol. 174, 5, 27p.Africa, Ethiopiaxenoliths

Abstract: The behavior of sub-continental lithospheric mantle (SCLM) in extensional settings, up to successful rifting, plays an important role in geodynamics and in the global carbon cycle, yet the underlying processes and rates of lithosphere destruction remain poorly constrained. We determined platinum-group element (PGE: Os, Ir, Ru, Pt, and Pd) abundances and Re-Os-isotope systematics for well-characterized mantle xenoliths hosted in Cenozoic basalts from the northwestern plateau (Gundeweyn area) and southern rift zone (Dillo and Megado areas) of Ethiopia to provide new insights on the nature and timing of processes leading to the formation and transformation of the off-cratonic lithospheric mantle beneath the East Africa rift system (EARS). The whole-rock PGE concentrations are highly variable, with total PGE abundances ranging from 6.6 to 12.6 ppb for Gundeweyn, 11.5 to 23.3 ppb for Dillo, and 9.9 to 19.4 ppb for Megado mantle xenoliths. The 187Os/188Os ratios of the whole-rock mantle xenoliths vary from 0.1180 to 0.1287 for Gundeweyn, 0.1238 to 0.1410 for Dillo and 0.1165 to 0.1277 for Megado, compared to 0.130 for the Afar plume and???0.14 for the Kenya plume, with Re depletion ages up to 1.45 Ga for Gundeweyn, 0.64 Ga for Dillo, and 1.65 Ga for Megado mantle xenoliths. The regional differences between refertilizing agents recorded in mantle xenoliths from the plateau area and the rift systems reflect distinct tectonomagmatic settings: (1) low PGE abundances, with some retention of low 187Os/188Os in Gundeweyn peridotites, are ascribed to scavenging by early small-volume oxidizing melts, generated in the convecting mantle ahead of the arrival of the Afar plume. (2) Percolation of late-stage silicate/basaltic melts, associated with the arrival of hot mantle plume and lithosphere thinning in the rift setting, locally led to refertilization and sulfide precipitation and partial replenishment of the PGE (Dillo), with convecting mantle-like 187Os/188Os. Local enclaves of older, cryptically metasomatised mantle with unradiogenic Os (Megado) attest to the heterogeneous nature of melt-peridotite interaction at this stage (pervasive vs. focused melt flow). Highly depleted abundances of the compatible PGE are characteristic of SCLM affected by incipient rifting and percolation of oxidizing melts, here associated with the Afar and Kenya plume beneath the East Africa rift, and may be precursors to advanced degrees of lithosphere destruction/transformation.
DS201112-0012
2010
Alencar de Carvalho Borges, M.P.Alencar de Carvalho Borges, M.P., Rahal Lenharo, S.L.Mineralogia dos diamantes da terra indigena Roosevelt-ro e implicacoes para a proveniencia e genese.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 52.South America, RondoniaOverview of area
DS201912-2767
2019
Alencastro, M.Alencastro, M.State - diamond sector relations in Angola, 1912-2002.Journal of Southern African Studies, Vol. 45, 5, pp. 805-820.Africa, South Africaeconomics

Abstract: Existing studies on mining in Angola are mostly concerned with its social and military underpinnings and tend to analyse the diamond sector as empirically distinct from the state. In addition, little attention has been paid to how they are bound together and what these interconnections mean for the nature of politics in Angola. This gap in the literature is significant because diamond companies produce far more than revenue and profits: for some 100?years, the diamond sector has governed, policed, defended and controlled the strategic, diamond-rich provinces of Lunda Sul and Lunda Norte. In order to fill this lacuna, this article offers a case study on the role of the diamond industry for the state in Angola from the creation of the first diamond company in 1917 to the end of the Angolan civil war in 2002. Drawing on a wide range of untapped official documents and on interviews, it argues that the diamond sector has functioned historically as the conduit through which the state projects its power and secures its interests in strategic but hostile territory.
DS1997-0018
1997
Alene, M.Alene, M., Barker, J.Geochemistry of metaigneous rocks from southern Ethiopia:new insight into Neoproterozoic tectonics.Journal of African Earth Sciences, Vol. 24, No. 3, April pp. 351-370GlobalGeochemistry, Tectonics
DS1993-0022
1993
Alepilov, V.D.Alepilov, V.D., Kramskov, N.The development and underground mining at the International pipeDiamonds of Yakutia, pp. 159-160.Russia, YakutiaMining, Deposit -International
DS200512-1202
2004
Aleqabi, G.Wysession, M., Fischer, K., Shore, P., Aleqabi, G.Waves across America: using a seismic array from Florida to Alberta to examine the geology beneath the middle of North America.Geological Society of America North Central Meeting ABSTRACTS, Vol. 36, 3. p. 47.Canada, AlbertaGeophysics - seismics - FLED
DS201801-0050
2017
Aleqabi, G.Pratt, M.J., Wysession, M.E., Aleqabi, G., Wiens, D.A., Nyblade, A., Shore, P., Rambolamanana, G., Andriampenomanana, F., Rakotondraibe, T., Tucker, R.D., Barruol, G., Rindraharisaona, E.Shear velocity structure of the crust and upper mantle of Madagascar derived from surface wave tomography.Earth and Planetary Science Letters, Vol. 458, 1, pp.405-417.Africa, Madagascargeophysics - seismics

Abstract: The crust and upper mantle of the Madagascar continental fragment remained largely unexplored until a series of recent broadband seismic experiments. An island-wide deployment of broadband seismic instruments has allowed the first study of phase velocity variations, derived from surface waves, across the entire island. Late Cenozoic alkaline intraplate volcanism has occurred in three separate regions of Madagascar (north, central and southwest), with the north and central volcanism active until <1 Ma, but the sources of which remains uncertain. Combined analysis of three complementary surface wave methods (ambient noise, Rayleigh wave cross-correlations, and two-plane-wave) illuminate the upper mantle down to depths of 150 km. The phase-velocity measurements from the three methods for periods of 8-182 s are combined at each node and interpolated to generate the first 3-D shear-velocity model for sub-Madagascar velocity structure. Shallow (upper 10 km) low-shear-velocity regions correlate well with sedimentary basins along the west coast. Upper mantle low-shear-velocity zones that extend to at least 150 km deep underlie the north and central regions of recent alkali magmatism. These anomalies appear distinct at depths <100 km, suggesting that any connection between the zones lies at depths greater than the resolution of surface-wave tomography. An additional low-shear velocity anomaly is also identified at depths 50-150 km beneath the southwest region of intraplate volcanism. We interpret these three low-velocity regions as upwelling asthenosphere beneath the island, producing high-elevation topography and relatively low-volume magmatism.
DS200812-0601
2008
Aleshin, I.Kozlovskaya, E., Kosarev, G., Aleshin, I., Riznichenko, O., Sanina, I.Structure and composition of the crust and upper mantle of the Archean Proterozoic boundary in the Fennoscandian Shield obtained by joint inversion.Geophysical Journal International, Vol. 175, 1, pp. 135-152.Europe, Scandinavia, Sweden, NorwayGeophysics - seismics
DS201905-1059
2019
Aleshin, M.Mortet, V., Vickova Zicova, Z., Taylor, A., Davydova, M., Frank, O,m Hubik, P., Lorincik, J., Aleshin, M.Determination of atomic boron concentration in heavily boron-doped diamond by Raman spectroscopy.Diamond & Related Materials, Vol. 93, pp. 54-58.Globalspectroscopy

Abstract: Raman spectroscopy has been foreseen as a simple and non-destructive characterization method to determine the boron concentration in heavily boron-doped diamond with metallic conductivity. However, currently available empirical studies are not fully satisfactory for enabling accurate determination of the boron concentration in diamond. Here, we study Raman spectra of epitaxial boron-doped diamond as a function of the boron concentration and the excitation wavelength. The zone center phonon and the phonon density of state maximum (at ca. 1200?cm?1) lines are analyzed using a decoupled double Fano-function. This analysis method accurately describes the observed variation of the asymmetric parameters with atomic boron concentration and the photon excitation energy and enables the determination of the atomic boron concentration from the parameters of the examined Raman lines.
DS1986-0749
1986
Aleskovskiy, V.B.Smirnov, E.P., Taushkanova, O.G., Aleskovskiy, V.B.The cation and anion exchange properties of diamonds.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 290, No. 4, pp. 901-904RussiaDiamond morphology
DS201511-1831
2015
Alessandri, M.Deljanin, B., Alessandri, M., Peretti, A., Astrom, M.NDT breaking the 10 carat barrier: world record faceted and gem-quality synthetic diamonds.Contributions to Gemology, Vol. 15, pp. 1-7.TechnologySynthetics

Abstract: The first small manufactured industrial diamonds were produced in 1953 by the Swedish company ASEA but their accomplishment went unannounced. In 1970, General Electric (GE) produced synthetic diamond crystals using the HPHT method with a belt type of press and created a 0.78ct polished RBC colorless diamond. In the 1980’s and 1990’s Russians used their own technology (“BARS” and “TOROID” high pressure apparatus (HPA) with high pressure presses of up to 25 MN load) to grow industrial and crystals up to 2.00ct in polished size, mostly orange to yellow in colour. In the last 15 years, companies including Lucent, Chatham, AOTC, Gemesis (now IIa Technologies) and many other producers in China, Germany, India, Russia, Ukraine, USA and Taiwan have improved the technology yet again and used their expertise to successfully grow diamond crystals that cut to 1.00ct up to 2.00ct in size. This “next generation” of diamonds exhibited high clarities (VS and VVS) and colours (D-H), as well as new blue and pink colours (after irradiation). Other companies (ref. 2-3) including Scio Diamonds, Washington Diamonds, Taidiam, PDC diamonds and Pure Grown Diamonds (selling arm of IIa technologies) are also using a very different technology/process of Chemical Vapour Deposition (CVD) to produce laboratory-grown diamonds up to 3.00 ct in size (table 1).
DS1993-0020
1993
Alessandro, V.Alberti, A., Alessandro, V., Pieruccini, U., Pranzini, E.Land sat Thematic Mapperdat a processing for lithological discrimination in the Caraculoarea (Namibe Province, southwest Angola).Journal of African Earth Sciences, Vol. 17, No. 3, October pp. 261-274.AngolaLandsat -not specific to diamonds, Remote sensing, lithology
DS202008-1461
2020
Alessi, D.S.Zeyen, N., Wang, B., Wilson, S.A., von Gunten, K., Alessi, D.S., Paulo, C., Stubbs, A.R., Power, I.M.Cation exchange: a new strategy for mineral carbonation of smectite-rich kimberlites.Goldschmidt 2020, 1p. AbstractAfrica, South Africadeposit - Venetia

Abstract: Mineral carbonation is a form of carbon capture, utilization and storage (CCUS) that aims to transform excess CO2 into environmentally benign carbonate minerals which are geologically stable. Here, we investigated the reactivity of processed kimberlite and kimberlite ore from the Venetia Diamond Mine (South Africa). Highly reactive phases, such as brucite [Mg(OH)2], are uncommon in the samples collected from Venetia necessitating the development of new strategies for mineral carbonation. Kimberlite ore and tailings from this mine consist of a clay-rich mineral assemblage that is dominated by lizardite (a serpentine mineral) and smectites. Smectites are swelling clays that can act as a source of Mg and Ca for carbonation reactions via cation exchange, dissolution and/or direct replacement of smectites to form carbonate phases. Although carbonation of serpentine and brucite has long been a focus of CCUS in mine wastes [1], smectite carbonation has not been explored in this setting. Quantitative X-ray diffraction using Rietveld refinements coupled with Fourier-transform infrared spectroscopy indicate that smectites of stevensite-saponite composition are abundant in the Venetia samples (1.3-15.4 wt.%). Synchrotron-based X-ray fluorescence mapping correlated with scanning and transmission electron microscopy show that smectites are distributed as altered, smooth regions measuring from 1 to 20 ?m in breadth. These phases are rich in Mg and Ca and Al-poor. To better understand the behaviour/reactivity of smectites during the cation exchange process, we have used batch experiments with pure endmembers of Ca-, Mg- and Na-montmorillonite under different treatment conditions (NH4-citrate, NH4-O-acetate, NH4-Cl and Na3-citrate). After 24 hours of reaction, ICP-MS analyses reveal that the four treatments have the same efficiency for Ca and Mg exchange, while NH4-Cl and NH4- O-acetate treatments minimize calcite dissolution. Our end goals are to optimize settling time and to maximize extraction of Ca and Mg for carbonation reactions during ore processing.
DS201705-0854
2017
Alessio, B.L.Merdith, A.S., Collins, A.S., Williams, S.E., Pisarevsky, S., Foden, J.F., Archibald, D., Blades, M.L., Alessio, B.L., Armistead, S., Plavsa, D., Clark, C., Muller, R.D.A full plate global reconstruction of the Neoproterozoic.Gondwana Research, in press available 155p.Gondwana, RodiniaGeodynamics

Abstract: Neoproterozoic tectonic geography was dominated by the formation of the supercontinent Rodinia, its break-up and the subsequent amalgamation of Gondwana. The Neoproterozoic was a tumultuous time of Earth history, with large climatic variations, the emergence of complex life and a series of continent-building orogenies of a scale not repeated until the Cenozoic. Here we synthesise available geological and palaeomagnetic data and build the first full-plate, topological model of the Neoproterozoic that maps the evolution of the tectonic plate configurations during this time. Topological models trace evolving plate boundaries and facilitate the evaluation of “plate tectonic rules” such as subduction zone migration through time when building plate models. There is a rich history of subduction zone proxies preserved in the Neoproterozoic geological record, providing good evidence for the existence of continent-margin and intra-oceanic subduction zones through time. These are preserved either as volcanic arc protoliths accreted in continent-continent, or continent-arc collisions, or as the detritus of these volcanic arcs preserved in successor basins. Despite this, we find that the model presented here still predicts less subduction (ca. 90%) than on the modern earth, suggesting that we have produced a conservative model and are likely underestimating the amount of subduction, either due to a simplification of tectonically complex areas, or because of the absence of preservation in the geological record (e.g. ocean-ocean convergence). Furthermore, the reconstruction of plate boundary geometries provides constraints for global-scale earth system parameters, such as the role of volcanism or ridge production on the planet's icehouse climatic excursion during the Cryogenian. Besides modelling plate boundaries, our model presents some notable departures from previous Rodinia models. We omit India and South China from Rodinia completely, due to long-lived subduction preserved on margins of India and conflicting palaeomagnetic data for the Cryogenian, such that these two cratons act as ‘lonely wanderers’ for much of the Neoproterozoic. We also introduce a Tonian-Cryogenian aged rotation of the Congo-São Francisco Craton relative to Rodinia to better fit palaeomagnetic data and account for thick passive margin sediments along its southern margin during the Tonian. The GPlates files of the model are released to the public and it is our expectation that this model can act as a foundation for future model refinements, the testing of alternative models, as well as providing constraints for both geodynamic and palaeoclimate models.
DS201709-2032
2017
Alessio, B.L.Meredith, A.S., Collins, A.S., Williams, S.E., Pisarevsky, S., Foden, J.D., Archibald, D.B., Blades, M.L., Alessio, B.L., Armistead, S., Plavsa, D., Clark, C., Muller, R.D.A full plate global reconstruction of the Neoproterozoic.Gondwana Research, Vol. 50, pp. 84-134.Globalneoproterozoic

Abstract: Neoproterozoic tectonic geography was dominated by the formation of the supercontinent Rodinia, its break-up and the subsequent amalgamation of Gondwana. The Neoproterozoic was a tumultuous time of Earth history, with large climatic variations, the emergence of complex life and a series of continent-building orogenies of a scale not repeated until the Cenozoic. Here we synthesise available geological and palaeomagnetic data and build the first full-plate, topological model of the Neoproterozoic that maps the evolution of the tectonic plate configurations during this time. Topological models trace evolving plate boundaries and facilitate the evaluation of “plate tectonic rules” such as subduction zone migration through time when building plate models. There is a rich history of subduction zone proxies preserved in the Neoproterozoic geological record, providing good evidence for the existence of continent-margin and intra-oceanic subduction zones through time. These are preserved either as volcanic arc protoliths accreted in continent-continent, or continent-arc collisions, or as the detritus of these volcanic arcs preserved in successor basins. Despite this, we find that the model presented here still predicts less subduction (ca. 90%) than on the modern earth, suggesting that we have produced a conservative model and are likely underestimating the amount of subduction, either due to a simplification of tectonically complex areas, or because of the absence of preservation in the geological record (e.g. ocean-ocean convergence). Furthermore, the reconstruction of plate boundary geometries provides constraints for global-scale earth system parameters, such as the role of volcanism or ridge production on the planet's icehouse climatic excursion during the Cryogenian. Besides modelling plate boundaries, our model presents some notable departures from previous Rodinia models. We omit India and South China from Rodinia completely, due to long-lived subduction preserved on margins of India and conflicting palaeomagnetic data for the Cryogenian, such that these two cratons act as ‘lonely wanderers’ for much of the Neoproterozoic. We also introduce a Tonian-Cryogenian aged rotation of the Congo-São Francisco Craton relative to Rodinia to better fit palaeomagnetic data and account for thick passive margin sediments along its southern margin during the Tonian. The GPlates files of the model are released to the public and it is our expectation that this model can act as a foundation for future model refinements, the testing of alternative models, as well as providing constraints for both geodynamic and palaeoclimate models.
DS201908-1769
2019
Alessio, B.L.Alessio, B.L., Glorie, S., Collins, A.S., Jourdan, F., Jepson, G., Nixon, A., Siegfried, P.R., Clark, C.The thermo-tectonic evolution of the southern Congo craton margin as determined from apatite and muscovite thermochronology.Tectonophysics, Vol. 766, pp. 398-415.Africa, Zambia, Malawi, Mozambique, Tanzaniacraton

Abstract: The Southern Irumide Belt (SIB) of Zambia consists of predominantly Mesoproterozoic terranes that record a pervasive tectono-metamorphic overprint from collision between the Congo and Kalahari cratons in the final stages of Gondwana amalgamation. This study applies multi-method thermochronology to samples throughout southern Zambia to constrain the post-collisional, Phanerozoic thermo-tectonic evolution of the region. U-Pb apatite and 40Ar/39Ar muscovite data are used to constrain the cooling history of the region following Congo-Kalahari collision, and reveal ages of c. 550-450?Ma. Variations in the recorded cooling ages are interpreted to relate to localised post-tectonic magmatism and the proximity of analysed samples to the Congo-Kalahari suture. Apatite fission track data are used to constrain the low-temperature thermo-tectonic evolution of the region and identify mean central ages of c. 320-300, 210-200 and 120-110?Ma. Thermal modelling of these samples identifies a number of thermal events occurring in the region throughout the Phanerozoic. Carboniferous to Permian-Triassic heating is suggested to relate to the development of Karoo rift basins found throughout central Africa and constrain the timing of sedimentation in the basin. Permian to Jurassic cooling is identified in a number of samples, reflecting exhumation as a result of the Mauritanian-Variscan and Gondwanide orogenies. Subsequent cooling of the majority of samples occurs from the Cretaceous and persists until present, reflecting exhumation in response to larger scale rifting associated with the break-up of Gondwana. Each model reveals a later phase of enhanced cooling beginning at c. 30?Ma that, if not an artefact of modelling, corresponds to the development of the East African Rift System. The obtained thermochronological data elucidate the previously unconstrained thermal evolution of the SIB, and provides a refined regional framework for constraining the tectonic history of central Africa throughout the Phanerozoic.
DS1991-0012
1991
Aleva, G.J.J.Aleva, G.J.J.Tropical weathering, denudation and mineral accumulationGeologie en Mijnbouw, Vol. 70, pp. 36-38IndonesiaGeneral weathering information, Mechanisms
DS201604-0590
2015
Alexakhin, V.Yu.Alexakhin, V.Yu., Bystritsky, V.M., Zamyatin, N.I., Zubarev, E.V., Krasnoperov, A.V., Rapatsky, V.L., Rogov, Yu.N., Sadovsky, A.B., Salamatin, A.V., Salmin, R.A., Sapozhnikov, M.G., Slepnev, V.M., Khabarov, S.V., Razinkov,E.A., Tarasov, O.G., Nikitin,G.M.Detection of diamonds in kimberlite by the tagged neutron method.Nuclear Instruments and Methods in Physics Research Section A., A785, pp. 9-13.TechnologyMethodology

Abstract: A new technology for diamond detection in kimberlite based on the tagged neutron method is proposed. The results of experimental researches on irradiation of kimberlite samples with 14.1-MeV tagged neutrons are discussed. The source of the tagged neutron flux is a portable neutron generator with a built-in 64-pixel silicon alpha-detector with double-sided stripped readout. Characteristic gamma rays resulting from inelastic neutron scattering on nuclei of elements included in the composition of kimberlite are registered by six gamma-detectors based on BGO crystals. The criterion for diamond presence in kimberlite is an increased carbon concentration within a certain volume of the kimberlite sample.
DS1950-0002
1950
AlexanderAlexanderThe Arkansaw Diamond CrystalThe Gemologist., Vol. 19, FEBRUARY P. 29; DECEMBER P. 279.United States, Gulf Coast, ArkansasDiamond Occurrence
DS201607-1301
2016
Alexander, B.D.Hart, E., Storey, C., Bruand, E., Schertl, H-P., Alexander, B.D.Mineral inclusions in rutile: a novel recorder of HP-UHP.Earth and Planetary Science Letters, Vol. 446, pp. 137-148.MantleCoesite, subduction

Abstract: The ability to accurately constrain the secular record of high- and ultra-high pressure metamorphism on Earth is potentially hampered as these rocks are metastable and prone to retrogression, particularly during exhumation. Rutile is among the most widespread and best preserved minerals in high- and ultra-high pressure rocks and a hitherto untested approach is to use mineral inclusions within rutile to record such conditions. In this study, rutiles from three different high- and ultrahigh-pressure massifs have been investigated for inclusions. Rutile is shown to contain inclusions of high-pressure minerals such as omphacite, garnet and high silica phengite, as well as diagnostic ultrahigh-pressure minerals, including the first reported occurrence of exceptionally preserved monomineralic coesite in rutile from the Dora -Maira massif. Chemical comparison of inclusion and matrix phases show that inclusions generally represent peak metamorphic assemblages; although rare prograde phases such as titanite, omphacite and corundum have also been identified implying that rutile grows continuously during prograde burial and traps mineralogic evidence of this evolution. Pressure estimates obtained from mineral inclusions, when used in conjunction with Zr-in-rutile thermometry, can provide additional constraints on the metamorphic conditions of the host rock. This study demonstrates that rutile is an excellent repository for high- and ultra-high pressure minerals and that the study of mineral inclusions in rutile may profoundly change the way we investigate and recover evidence of such events in both detrital populations and partially retrogressed samples.
DS1997-0746
1997
Alexander, C.J.McAllister, M.L., Alexander, C.J.A stake in the future: redefining the Canadian Mineral IndustryUbc Press, 248p. approx. $ 75.00CanadaBook - ad, Mineral industry - future, legal
DS201707-1301
2017
Alexander, C.M.O'D.Alexander, C.M.O'D., Cody, G.D., De Gregorio, B.T., Nittler, L.R., Stroud, R.M.The nature, origin and modification of insoluable organic matter in chondrites, the major source of Earth's C and N.Chemie der Erde, Vol. 77, pp. 227-256.Mantlemeteorites

Abstract: All chondrites accreted ?3.5 wt.% C in their matrices, the bulk of which was in a macromolecular solvent and acid insoluble organic material (IOM). Similar material to IOM is found in interplanetary dust particles (IDPs) and comets. The IOM accounts for almost all of the C and N in chondrites, and a significant fraction of the H. Chondrites and, to a lesser extent, comets were probably the major sources of volatiles for the Earth and the other terrestrial planets. Hence, IOM was both the major source of Earth’s volatiles and a potential source of complex prebiotic molecules. Large enrichments in D and 15N, relative to the bulk solar isotopic compositions, suggest that IOM or its precursors formed in very cold, radiation-rich environments. Whether these environments were in the interstellar medium (ISM) or the outer Solar System is unresolved. Nevertheless, the elemental and isotopic compositions and functional group chemistry of IOM provide important clues to the origin(s) of organic matter in protoplanetary disks. IOM is modified relatively easily by thermal and aqueous processes, so that it can also be used to constrain the conditions in the solar nebula prior to chondrite accretion and the conditions in the chondrite parent bodies after accretion. Here we review what is known about the abundances, compositions and physical nature of IOM in the most primitive chondrites. We also discuss how the IOM has been modified by thermal metamorphism and aqueous alteration in the chondrite parent bodies, and how these changes may be used both as petrologic indicators of the intensity of parent body processing and as tools for classification. Finally, we critically assess the various proposed mechanisms for the formation of IOM in the ISM or Solar System.
DS1994-0033
1994
Alexander, D.Alexander, D.Lytton Northwest Territories prospectsThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Section Meeting Oct. 12, Vancouver, List of speakersNorthwest TerritoriesUpdate
DS1975-0659
1978
Alexander, D.H.Alexander, D.H., Heinrich, E.W.Geology and Petrogenesis of the Mcclure Mountains Mafic Alkalic Carbonatitic Complex, Fremont County, Colorado.Geological Society of America (GSA), Vol. 10, No. 6, P. 245. (abstract.).United States, Colorado, Rocky MountainsCarbonatite
DS1975-0660
1978
Alexander, D.H.Alexander, D.H., Heinrich, E.W.Geology and Petrogenesis of the Mcclure Mountain Mafic Alkalic Carbonatitic Complex, Fremont County, Colorado.Geological Society of America (GSA), Vol. 10, No. 6, P. 245. (abstract.).United States, Colorado, Rocky MountainsBlank
DS202001-0044
2019
Alexander, E.W.Tang, F., Taylor, R.J.M., Einsle, J.F., Borlina, C.S., Fu, R.R., Weiss, B.P., Williams, H.M., Williams, W., Nagy, L., Midgley, P.A., Lima, E.A., Bell, E.A., Harrison, T.M., Alexander, E.W., Harrison, R.J.Secondary magnetite in ancient zircon precludes analysis of a Hadean geodynamo. Jack HillsProceedings National Academy of Science, Vol. 116, pp. 407-412.Australiapaleomagnetism

Abstract: Zircon crystals from the Jack Hills, Western Australia, are one of the few surviving mineralogical records of Earth’s first 500 million years and have been proposed to contain a paleomagnetic record of the Hadean geodynamo. A prerequisite for the preservation of Hadean magnetization is the presence of primary magnetic inclusions within pristine igneous zircon. To date no images of the magnetic recorders within ancient zircon have been presented. Here we use high-resolution transmission electron microscopy to demonstrate that all observed inclusions are secondary features formed via two distinct mechanisms. Magnetite is produced via a pipe-diffusion mechanism whereby iron diffuses into radiation-damaged zircon along the cores of dislocations and is precipitated inside nanopores and also during low-temperature recrystallization of radiation-damaged zircon in the presence of an aqueous fluid. Although these magnetites can be recognized as secondary using transmission electron microscopy, they otherwise occur in regions that are indistinguishable from pristine igneous zircon and carry remanent magnetization that postdates the crystallization age by at least several hundred million years. Without microscopic evidence ruling out secondary magnetite, the paleomagnetic case for a Hadean-Eoarchean geodynamo cannot yet been made.
DS1990-0111
1990
Alexander, J.Alexander, J., Leeder, M.R.Geomorphology and surface tilting in an active extensional basin, southwestMontana, USAJournal of the Geological Society of London, Vol. 147, pt. 3, May pp. 461-468MontanaGeomorphology, Basin
DS1859-0062
1838
Alexander, J.E.Alexander, J.E.An Expedition of Discovery into the Interior of AfricaLondon: Henry Colburn., TWO VOLS. 302P.; 306P.Southwest Africa, NamibiaTravelogue
DS1982-0563
1982
Alexander, P.O.Shrivastava, V.K., Alexander, P.O.Geobotanical Expression of a Blind Kimberlite Pipe, Centralindia. #1Proceedings of Third International Kimberlite Conference, TERRA, Vol. 2, No. 3, PP. 203-204, (abstract.).India, Madhya PradeshGeobotany, Signature, Prospecting, Soil Analyses
DS1983-0005
1983
Alexander, P.O.Alexander, P.O.Looking for Diamonds? Try GeobotanyIndiaqua., No. 36, 1983/3, PP. 33-35; 37-38.India, PannaKimberlite, Pipe, Signature, Analyses, Case History, Remote Sensing
DS1983-0436
1983
Alexander, P.O.Mathur, S.M., Alexander, P.O.Preliminary Pedogeochemical and Biogeochemical Studies on The Hinota Kimberlite, Panna District, India.Indian Academy of Science Proceedings, Vol. 92, No. 1, MARCH, PP. 81-88.India, Panna, Madhya PradeshGeochemistry
DS1984-0007
1984
Alexander, P.O.Alexander, P.O., Shrivastava, V.K.Geobotanical Expression of a Blind Kimberlite Pipe, Centralindia. #2Proceedings of Third International Kimberlite Conference., Vol. 1, PP. 33-42.Andhra Pradesh, Panna, ThailandGeobotany, Geomorphology, Remote Sensing
DS1986-0009
1986
Alexander, P.O.Alexander, P.O.Preliminary study of soil bacterial populations over and adjacent to three kimberlite diatremesProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 440-442IndiaDiamond exploration
DS1986-0010
1986
Alexander, R.W.S.Alexander, R.W.S., Dawson, J.B., Patterson, E.M., Hervig, R.L.The megacryst and inclusion assemblage from the Black Rock vent, AyrshireScottish Journal of Geology, Vol. 22, No. P2, pp. 203-212ScotlandPetrology, Inclusions
DS1920-0054
1921
Alexander, S.Alexander, S.Origin of the Diamond (1921)Mining Engineering Journal of South Africa, Vol. 32, PT. 2, Dec. 3RD. P. 490.South AfricaDiamond Genesis
DS1986-0685
1986
Alexander, S.S.Ruder, M.E., Alexander, S.S.Magsat equivalent source anomalies over the southeastern United States:implications for crustal magnetizationEarth and Planetary Science Letters, Vol. 78, No. 1, May pp. 33-43Midcontinent, Alabama, Georgia, AppalachiaGeophysics
DS1989-0807
1989
Alexander, S.S.Kohler, J.L., Elsworth, D., Alexander, S.S.Mining on the moonEarth and Mineral Sciences (Penn. State), Vol. 58, No. 1, pp. 6-9. Database # 17691MoonOverview, Economics
DS200812-0015
2008
Alexandrino, C.H.Alexandrino, C.H., Hamza, V.M.Estimates of heat flow and heat production and a thermal model of the Sao Francisco craton.International Journal of Earth Sciences, Vol. 97, 2, April pp. 1437-3254South America, BrazilCraton, geothermometry
DS200812-0016
2008
Alexandrino, C.H.Alexandrino, C.H., Hamza, V.M.Estimates of heat flow and heat production and a thermal model of the Sao Francisco Craton.International Journal of Earth Sciences, Vol. 97, 2, pp. 289-306.South America, BrazilGeothermometry
DS2001-1013
2001
AlexandrovSarayev, A.L., Pertel, Garat, Manakov, AlexandrovPossibilities of magnetotellurics for kimberlite exploration in the Russian PlatformNorth Atlantic Minerals Symposium held May 27-30, pp. 149. abstract.RussiaGeophysics - magnetotellurics
DS1995-0428
1995
Alexandrov, S.P.Dobrynina, M.I., Alexandrov, S.P., Garber, D.I.Kimberlites of the Arkhangelsk diamond province review of their structuralsetting, petrophysical characters.American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, No. 95-151, 6p.Russia, ArkangelskStructure, Deposit -Arkhangel
DS200812-1116
2008
Alexeev, A.G.Steier, P., Liechtenstein, V.K., Djokic, D., Golser, R., Wallner, A., Alexeev, A.G., Khrunov, V.S., KutscheraCharacterization and improvement of thin natural diamond detectors for spectrometry of heavy ions below 1 MeV/amu.Nuclear Instruments and Methods in Physics Research Section A., Vol. 590, 1-3, pp. 221-226.TechnologySpectrometry
DS1995-0171
1995
Alexeev, S.V.Borisov, V.N., Alexeev, S.V., Pleshevenkova, V.A.The diamond mining quarries of East Siberia as a factor affecting surficial water quality.Gems and gemology, Gemological Abstracts, Vol. 32, Winter, p. 298.Russia, SiberiaMining, Diamond
DS2002-0019
2002
Alexeev, S.V.Alexeev, S.V., Alexeeva, L.P.Ground ice in the sedimentary rocks and kimberlites of Yakutia, RussiaPermafrost and Periglacial Processes, Vol.13,1,pp. 53-60.RussiaKimberlite - stratigraphy
DS201603-0363
2016
Alexeev, S.V.Alexeev, S.V., Alexeeva, L.P., Kononov, A.M.Trace elements and rare earth elements in ground ice in kimberlites and sedimentary rocks of western Yakutia.Cold Regions Science and Technology, Vol. 123, pp. 140-148.RussiaGeomorphology

Abstract: The paper presents unique results of studying the composition of the ground ice (major components, trace elements, and rare earth elements — REEs) encountered at a depth of 200-250 m in sedimentary and magmatic rocks in the Western Yakutia diamond-bearing regions. In addition to those established earlier, three new geochemical types of ground ice have been defined: (i) sulfate-hydrocarbonate, (ii) chloride-hydrocarbonate, and (iii) sulfate-chloride types with mixed cation composition. The ground ice geochemical features are caused by evolutionary processes of interaction in the water-rock system during permafrost formation. The enclosed rocks were the source for the addition of sulfate and chlorine ions, as well as trace elements, to the ground waters of the active water exchange zone that had existed before freezing. The distribution pattern of REEs in ground ice has a special form distinct from that of sedimentary rocks, kimberlites, and ocean waters, but similar to the REE pattern in local river waters. This REE pattern features the positive europium (Eu) anomaly and approximate equality of light and heavy REEs. The obtained results essentially expand the insight into ice-formation processes in sedimentary and magmatic rocks.
DS201612-2273
2016
Alexeev, S.V.Alexeev, S.V., Alexeeva, L.P., Kononov, A.M.Trace elements and rare earth elements in ground ice in kimberlites and sedimentary rocks of western Yakutia.Cold Regions Science and Technology, Vol. 123, pp. 140-148.Russia, YakutiaGeomorphology

Abstract: The paper presents unique results of studying the composition of the ground ice (major components, trace elements, and rare earth elements - REEs) encountered at a depth of 200-250 m in sedimentary and magmatic rocks in the Western Yakutia diamond-bearing regions. In addition to those established earlier, three new geochemical types of ground ice have been defined: (i) sulfate-hydrocarbonate, (ii) chloride-hydrocarbonate, and (iii) sulfate-chloride types with mixed cation composition. The ground ice geochemical features are caused by evolutionary processes of interaction in the water-rock system during permafrost formation. The enclosed rocks were the source for the addition of sulfate and chlorine ions, as well as trace elements, to the ground waters of the active water exchange zone that had existed before freezing. The distribution pattern of REEs in ground ice has a special form distinct from that of sedimentary rocks, kimberlites, and ocean waters, but similar to the REE pattern in local river waters. This REE pattern features the positive europium (Eu) anomaly and approximate equality of light and heavy REEs. The obtained results essentially expand the insight into ice-formation processes in sedimentary and magmatic rocks.
DS2002-0019
2002
Alexeeva, L.P.Alexeev, S.V., Alexeeva, L.P.Ground ice in the sedimentary rocks and kimberlites of Yakutia, RussiaPermafrost and Periglacial Processes, Vol.13,1,pp. 53-60.RussiaKimberlite - stratigraphy
DS201603-0363
2016
Alexeeva, L.P.Alexeev, S.V., Alexeeva, L.P., Kononov, A.M.Trace elements and rare earth elements in ground ice in kimberlites and sedimentary rocks of western Yakutia.Cold Regions Science and Technology, Vol. 123, pp. 140-148.RussiaGeomorphology

Abstract: The paper presents unique results of studying the composition of the ground ice (major components, trace elements, and rare earth elements — REEs) encountered at a depth of 200-250 m in sedimentary and magmatic rocks in the Western Yakutia diamond-bearing regions. In addition to those established earlier, three new geochemical types of ground ice have been defined: (i) sulfate-hydrocarbonate, (ii) chloride-hydrocarbonate, and (iii) sulfate-chloride types with mixed cation composition. The ground ice geochemical features are caused by evolutionary processes of interaction in the water-rock system during permafrost formation. The enclosed rocks were the source for the addition of sulfate and chlorine ions, as well as trace elements, to the ground waters of the active water exchange zone that had existed before freezing. The distribution pattern of REEs in ground ice has a special form distinct from that of sedimentary rocks, kimberlites, and ocean waters, but similar to the REE pattern in local river waters. This REE pattern features the positive europium (Eu) anomaly and approximate equality of light and heavy REEs. The obtained results essentially expand the insight into ice-formation processes in sedimentary and magmatic rocks.
DS201612-2273
2016
Alexeeva, L.P.Alexeev, S.V., Alexeeva, L.P., Kononov, A.M.Trace elements and rare earth elements in ground ice in kimberlites and sedimentary rocks of western Yakutia.Cold Regions Science and Technology, Vol. 123, pp. 140-148.Russia, YakutiaGeomorphology

Abstract: The paper presents unique results of studying the composition of the ground ice (major components, trace elements, and rare earth elements - REEs) encountered at a depth of 200-250 m in sedimentary and magmatic rocks in the Western Yakutia diamond-bearing regions. In addition to those established earlier, three new geochemical types of ground ice have been defined: (i) sulfate-hydrocarbonate, (ii) chloride-hydrocarbonate, and (iii) sulfate-chloride types with mixed cation composition. The ground ice geochemical features are caused by evolutionary processes of interaction in the water-rock system during permafrost formation. The enclosed rocks were the source for the addition of sulfate and chlorine ions, as well as trace elements, to the ground waters of the active water exchange zone that had existed before freezing. The distribution pattern of REEs in ground ice has a special form distinct from that of sedimentary rocks, kimberlites, and ocean waters, but similar to the REE pattern in local river waters. This REE pattern features the positive europium (Eu) anomaly and approximate equality of light and heavy REEs. The obtained results essentially expand the insight into ice-formation processes in sedimentary and magmatic rocks.
DS1982-0007
1982
Alexeevski, K.M.Alexeevski, K.M., Botkunov, A.I., et al.Kelphite of Pyrope in SandstonesDoklady Academy of Sciences AKAD. NAUK SSSR., Vol. 265, No. 6, PP. 1475-1477.RussiaBlank
DS1985-0005
1985
Alexseevskii, K.M.Alexseevskii, K.M., Botkunov, A.I., Nikolaeva, T.T., Ermilov.Chemical Changes of the Environment of Diamond Genesis.(russian)Vopr. Orudeneniya Ul'tramfitakh, Nauka Moscow, (Russian), pp. 105-117RussiaBlank
DS2002-0020
2002
Alfe, D.Alfe, D., Gillan, M.J., Price, G.D.Composition and temperature of the Earth's core constrained by combining ab initio calculations/seismicEarth and Planetary Science Letters, Vol. 195, No. 1-2, pp. 91-8.MantleGeophysics - seismics, Geochemistry
DS2003-0007
2003
Alfe, D.Alfe, D., Gillan, M.J., Price, G.D.Thermodynamics from first principles: temperature and composition of the Earth's coreMineralogical Magazine, Vol. 67, 1, pp. 113-24.MantleGeothermometry
DS2003-0008
2003
Alfe, D.Alfe, D., Gillan, M.J., Price, G.D.Thermodynamics from first principles: temperature and composition of the Earth's coreMineralogical Magazine, Vol. 67, 1, Feb. pp. 113-124.MantleGeothermometry
DS200412-0741
2004
Alfe, D.Gubbins, D., Alfe, D., Masters, G., Price, G.D., Gillan, M.Gross thermodynamics of two component core convection.Geophysical Journal International, Vol. 157, 3, pp. 1407-1414.MantleConvection
DS201212-0571
2012
Alfe, D.Pozzo, M., Davies, C., Gubbins, D., Alfe, D.Thermal and electrical conductivity of iron at Earth's core.Nature, in press availableMantleGeothermometry
DS201312-0380
2013
Alfe, D.Hernandez, E.R., Alfe, D., Brodholt, J.The in corporation of water into lower mantle perovskites: a first principles study.Earth and Planetary Science Letters, Vol. 364, pp. 37-43.MantlePerovskite
DS201412-0708
2014
Alfe, D.Pozzo, M., Davies, C., Gubbins, D., Alfe, D.Thermal and electrical conductivity of solid iron and iron-silicon mixtures at Earth's core conditions.Earth and Planetary Science Letters, Vol. 393, pp. 159-165.MantleGeothermometry
DS201509-0392
2015
Alfe, D.Davies, C., Pozzo, M., Gubbins, D., Alfe, D.Constraints from material properties on the dynamics and evolution of Earth's core.Nature Geoscience, Vol. 8, pp. 678-785.MantleHT - core evolution

Abstract: The Earth’s magnetic field is powered by energy supplied by the slow cooling and freezing of the liquid iron core. Efforts to determine the thermal and chemical history of the core have been hindered by poor knowledge of the properties of liquid iron alloys at the extreme pressures and temperatures that exist in the core. This obstacle is now being overcome by high-pressure experiments and advanced mineral physics computations. Using these approaches, updated transport properties for FeSiO mixtures have been determined at core conditions, including electrical and thermal conductivities that are higher than previous estimates by a factor of two to three. Models of core evolution with these high conductivities suggest that the core is cooling much faster than previously thought. This implies that the solid inner core formed relatively recently (around half a billion years ago), and that early core temperatures were high enough to cause partial melting of the lowermost mantle. Estimates of core-mantle boundary heat flow suggest that the uppermost core is thermally stratified at the present day.
DS201811-2557
2015
Alferova, M.S.Boyd, W.F., Alferova, M.S.Emeralds in Russia: the geological and gemology of the Malyshev mine.InColor, December pp. 78-87.Russiaemeralds
DS2003-0772
2003
Alfieri, A.Lange, G.M., Hassan, R., Alfieri, A.Using environmental accounts to promote sustainable development: experience inNatural Resources Forum, Vol. 27, 1, pp. 19-31.South AfricaSustainability - not specific to diamonds
DS200412-1083
2003
Alfieri, A.Lange, G.M., Hassan, R., Alfieri, A.Using environmental accounts to promote sustainable development: experience in southern Africa.Natural Resources Forum, Vol. 27, 1, pp. 19-31.Africa, South AfricaSustainability - not specific to diamonds
DS200512-0010
2004
Alfonso, J.C.Alfonso, J.C., Ranalli, G.Crustal and mantle strengths in continental lithosphere: is the jelly sandwich model obsolete?Tectonophysics, Vol. 394, 3-4, Dec. 1-, pp. 221-232.MantleRheology, composition
DS200812-0017
2008
Alfonso, J.C.Alfonso, J.C., Fernandez, M., Ranalli, G., Griffin, W.L., Connolly, J.A.D.Integrated geophysical petrological modelling of the lithosphere and sublithospheric upper mantle: methodology and applications.Journal of Geophysical Research, in press available ( 97p.)MantleModels
DS201712-2697
2017
Alfonso, J.C.Jones, A.G., Alfonso, J.C., Fullea, J.Geochemical and geophysical constrains on the dynamic topography of the southern African plateau.Geochemistry, Geophysics, Geosystems, Vol. 18, 10, pp. 3556-3575.Africa, South Africageodynamics

Abstract: The deep mantle African Superswell is considered to contribute to the topographic uplift of the Southern African Plateau, but dynamic support estimates vary wildly depending on the approach and data used. One reason for these large disparities is that the role of lithospheric structure, key in modulating deep dynamic contributions to elevation, is commonly ignored or oversimplified in convection studies. We use multiple high-quality geophysical data coupled with xenolith-based geochemical constraints to compute the isostatic lithospheric contribution to the elevation of the Plateau, facilitating isolation of the current dynamic component from the total observed elevation. We employ a multiobservable stochastic algorithm to invert geoid anomaly, surface-wave dispersion data, magnetotelluric data, and surface heat flow to predict elevation in a fully thermodynamically and internally-consistent manner. We find that a compositionally layered 230?±?7 km thick lithosphere is required to simultaneously fit all four data types, in agreement with abundant independent xenolith evidence. Our stochastic modeling indicates a lithospheric contribution to elevation of the order of 670 m, which implies dynamic support arising from the convecting sublithospheric mantle of ?650 m. Our results have important implications for the understanding of lithospheric-deep mantle feedback mechanisms and for calibrating dynamic topography estimates from global convection studies.
DS202103-0398
2020
Alfonso, J.C.Oliveira, B., Alfonso, J.C., Tilhac, R.A disequilibrium reactive transport model for mantle magmatism.Journal of Petrology, Vol. 61, 9, egaa067, 35p. PdfMantlemagmatism

Abstract: Besides standard thermo-mechanical conservation laws, a general description of mantle magmatism requires the simultaneous consideration of phase changes (e.g. from solid to liquid), chemical reactions (i.e. exchange of chemical components) and multiple dynamic phases (e.g. liquid percolating through a deforming matrix). Typically, these processes evolve at different rates, over multiple spatial scales and exhibit complex feedback loops and disequilibrium features. Partially as a result of these complexities, integrated descriptions of the thermal, mechanical and chemical evolution of mantle magmatism have been challenging for numerical models. Here we present a conceptual and numerical model that provides a versatile platform to study the dynamics and nonlinear feedbacks inherent in mantle magmatism and to make quantitative comparisons between petrological and geochemical datasets. Our model is based on the combination of three main modules: (1) a Two-Phase, Multi-Component, Reactive Transport module that describes how liquids and solids evolve in space and time; (2) a melting formalism, called Dynamic Disequilibirum Melting, based on thermodynamic grounds and capable of describing the chemical exchange of major elements between phases in disequilibrium; (3) a grain-scale model for diffusion-controlled trace-element mass transfer. We illustrate some of the benefits of the model by analyzing both major and trace elements during mantle magmatism in a mid-ocean ridge-like context. We systematically explore the effects of mantle potential temperature, upwelling velocity, degree of equilibrium and hetererogeneous sources on the compositional variability of melts and residual peridotites. Our model not only reproduces the main thermo-chemical features of decompression melting but also predicts counter-intuitive differentiation trends as a consequence of phase changes and transport occurring in disequilibrium. These include a negative correlation between Na2O and FeO in melts generated at the same Tp and the continued increase of the melt’s CaO/Al2O3 after Cpx exhaustion. Our model results also emphasize the role of disequilibrium arising from diffusion for the interpretation of trace-element signatures. The latter is shown to be able to reconcile the major- and trace-element compositions of abyssal peridotites with field evidence indicating extensive reaction between peridotites and melts. The combination of chemical disequilibrium of major elements and sluggish diffusion of trace elements may also result in weakened middle rare earth to heavy rare earth depletion comparable with the effect of residual garnet in mid-ocean ridge basalt, despite its absence in the modelled melts source. We also find that the crystallization of basalts ascending in disequilibrium through the asthenospheric mantle could be responsible for the formation of olivine gabbros and wehrlites that are observed in the deep sections of ophiolites. The presented framework is general and readily extendable to accommodate additional processes of geological relevance (e.g. melting in the presence of volatiles and/or of complex heterogeneous sources, refertilization of the lithospheric mantle, magma channelization and shallow processes) and the implementation of other geochemical and isotopic proxies. Here we illustrate the effect of heterogeneous sources on the thermo-mechanical-chemical evolution of melts and residues using a mixed peridotite-pyroxenite source.
DS202105-0781
2021
Alfonso, J.C.Pamato, M.G., Novella, D., Jacobs, D.E., Oliveira, B., Pearson, D.G., Greene, S., Alfonso, J.C., Favero, M., Stachel, T., Alvaro, M., Nestola, F.Protogenetic sulfide inclusions in diamonds date the diamond formation event using Re-Os isotopes. Victor, JerichoGeology , Vol. 49, 4, 5p. Canada, Ontario, Nunavutdiamond inclusions

Abstract: Sulfides are the most abundant inclusions in diamonds and a key tool for dating diamond formation via Re-Os isotopic analyses. The manner in which fluids invade the continental lithospheric mantle and the time scale at which they equilibrate with preexisting (protogenetic) sulfides are poorly understood yet essential factors to understanding diamond formation and the validity of isotopic ages. We investigated a suite of sulfide-bearing diamonds from two Canadian cratons to test the robustness of Re-Os in sulfide for dating diamond formation. Single-crystal X-ray diffraction (XRD) allowed determination of the original monosulfide solid-solution (Mss) composition stable in the mantle, indicating subsolidus conditions of encapsulation, and providing crystallographic evidence supporting a protogenetic origin of the inclusions. The results, coupled with a diffusion model, indicate Re-Os isotope equilibration is sufficiently fast in sulfide inclusions with typical grain size, at mantle temperatures, for the system to be reset by the diamond-forming event. This confirms that even if protogenetic, the Re-Os isochrons defined by these minerals likely reflect the ages of diamond formation, and this result highlights the power of this system to date the timing of fluid migration in mantle lithosphere.
DS201412-0096
2014
Alfonso, P.Campeny, M., Mangas, J., Melgarejo, J.C., Bambi, A., Alfonso, P., Gernon, T., Manuel, J.The Catanga extrusive carbonatites ( Kwanza Sul, Angola): an example of explosive carbonatitic volcanism.Bulletin of Volcanology, Vol. 76, pp. 818-Africa, AngolaCarbonatite
DS201509-0387
2015
Alfonso, P.Campeny, M., Kamenetsky, V.S., Melgarejo, J.C., Mangas, J., Manuel, J., Alfonso, P., Kamenetsky, M.B., Bambi, A.C.J.M., Goncalves, A.O.Carbonatitic lavas in CatAnd a ( Kwanza Sul, Angola): mineralogical and geochemical constraints on the parental melt.Lithos, Vol. 232, pp. 1-11.Africa, AngolaCarbonatite

Abstract: A set of small volcanic edifices with tuff ring and maar morphologies occur in the Catanda area, which is the only locality with extrusive carbonatites reported in Angola. Four outcrops of carbonatite lavas have been identified in this region and considering the mineralogical, textural and compositional features, we classify them as: silicocarbonatites (1), calciocarbonatites (2) and secondary calciocarbonatites produced by the alteration of primary natrocarbonatites (3). Even with their differences, we interpret these lava types as having been a single carbonatite suite related to the same parental magma. We have also estimated the composition of the parental magma from a study of melt inclusions hosted in magnetite microphenocrysts from all of these lavas. Melt inclusions revealed the presence of 13 different alkali-rich phases (e.g., nyerereite, shortite, halite and sylvite) that argues for an alkaline composition of the Catanda parental melts. Mineralogical, textural, compositional and isotopic features of some Catanda lavas are also similar to those described in altered natrocarbonatite localities worldwide such as Tinderet or Kerimasi, leading to our conclusion that the formation of some Catanda calciocarbonatite lavas was related to the occurrence of natrocarbonatite volcanism in this area. On the other hand, silicocarbonatite lavas, which are enriched in periclase, present very different mineralogical, compositional and isotopic features in comparison to the rest of Catanda lavas. We conclude that its formation was probably related to the decarbonation of primary dolomite bearing carbonatites.
DS1860-0351
1881
Alfonzo, X.Alfonzo, X.LapidarioImprenta De la Iberia Cargo De J. Blasco, 20P.Europe, Spain, GlobalGemology
DS1988-0072
1988
Alford, C.Borradaile, G.J., Alford, C.Experimental shear zones and magnetic fabricsJournal of Structural Geology, Vol. 10, No. 8, pp. 895-904. Database # 17568GlobalShear zones, Structure- Magnetic fabrics
DS1860-0683
1891
Alford, C.J.Alford, C.J.Geological Features of the Transvaal of South AfricaLondon:, PP. 6-69.Africa, South AfricaRegional Geology
DS1986-0011
1986
Alford, P.Alford, P.Diamond quest facing the crunchAustralian Business, Vol. 6, No. 19, July 30, p. 99AustraliaEconomics, Diamond
DS1986-0012
1986
Alford, P.Alford, P.Steaming ahead into uncertain seasRegister of Australian Mining 1985-1986, pp. 319-327Australia, Western AustraliaBow River, Nicholson River, Production, Central Kimberley, News item, River, Queensland
DS1989-0020
1989
Alford, P.Alford, P.Bow River gives Australia a major second string. Argyledescribed, Kimberley area in general, Northern Territory, New South Wales, South Australia, QueenslandRegister of Australian Mining 1988/89, pp. 365-371AustraliaBrief overview
DS1991-1214
1991
Alford, R.A.Napier-Nunn, T.J., Alford, R.A.The causes of heavy mineral loss from mineral sands wet concentratorsAusIMM Proceedings, No. 1, 1991 pp. 19-30AustraliaHeavy minerals, Gravity concentration
DS1860-0166
1872
Algar, F.Algar, F.The Diamond Fields. With Notes on the Cape Colony and NatalLondon:, 64P.Africa, South Africa, Griqualand West History
DS1993-0023
1993
Algeo, T.J.Algeo, T.J.Quantifying stratigraphic completeness: a probabilistic approach using paleomagnetic dataJournal of Geology, Vol. 101, No. 3, July, pp. 421-434GlobalPaleomagnetics, Stratigraphy
DS1995-0019
1995
Algeo, T.J.Algeo, T.J., Seslabinsky, K.R.The Paleozoic world: continental flooding, hypsometry and sea levelAmerican Journal of Science, Vol. 295, Summer, pp. 787-822China, SiberiaEustasy, Paleocontinental flooding
DS1995-0020
1995
Algeo, T.J.Algeo, T.J., Seslavinsky, K.B.The Paleozoic world: continental flooding, hysometry, and sea levelAmerican Journal of Science, Vol. 295, summer, pp. 787-822.Baltica, China, Kazakhstan, Siberia, RussiaGeomorphology - flooding record
DS1981-0399
1981
Algermissen, S.T.Stover, C.W., Reagor, B.G., Algermissen, S.T.Seismicity Map of the State of KansasUnited States Geological Survey (USGS) MAP, No. MF-1351, 1:1, 000, 000.KansasMid Continent
DS1982-0596
1982
Algermissen, S.T.Thenhaus, P.C., Algermissen, S.T., Perkins, D.M.A New Seismic Source Zone Map for the Conterminous United States.Geological Society of America (GSA), Vol. 14, No. 7, P. 630, (abstract.).GlobalMid-continent, Geophysics
DS1984-0362
1984
Algermissen, S.T.Hopper, M.G., Algermissen, S.T.Types of Damage that Could Result from a Great Earthquake In the New Madrid Missouri Seismic Zone.United States Geological Survey (USGS) MAP, MF 1713.GlobalMid Continent
DS1987-0715
1987
Algermissen, S.T.Stover, C.W., Reagor, B.G., Algermissen, S.T.Seismicity map of LouisianaUnited States Geological Survey (USGS) Map, No. MF-1081 1:1, 000, 000GlobalGeophysics
DS1987-0716
1987
Algermissen, S.T.Stover, C.W., Reagor, B.G., Algermissen, S.T.Seismicity map of New YorkUnited States Geological Survey (USGS) Map, No. MF-1282 1:1, 000, 000GlobalGeophysics
DS1987-0717
1987
Algermissen, S.T.Stover, C.W., Reagor, B.G., Algermissen, S.T.Seismicity map of OhioUnited States Geological Survey (USGS) Map, No. MF-1975 1:1, 000, 000GlobalGeophysics
DS1987-0718
1987
Algermissen, S.T.Stover, C.W., Reagor, B.G., Algermissen, S.T.Seismicity map of IndianaUnited States Geological Survey (USGS) Map, No. MF-1974 1: 1, 000, 000IndianaGeophysics
DS1987-0719
1987
Algermissen, S.T.Stover, C.W., Reagor, B.G., Algermissen, S.T.Seismicity map of KentuckyUnited States Geological Survey (USGS) Map, No. MF-1144 1:1, 000, 000KentuckyGeophysics
DS201612-2322
2016
Algouti, A.Mourabit, Z., Tabit, A., Algouti, A., Algouti, A.The Beni Bousera peridotite ( Rif Belt, Morocco): a subsolidus evolution interpretation.Acta Geologica Sinica, Vol. 90, July abstract p. 111.Africa, MoroccoPeridotite
DS201612-2322
2016
Algouti, A.Mourabit, Z., Tabit, A., Algouti, A., Algouti, A.The Beni Bousera peridotite ( Rif Belt, Morocco): a subsolidus evolution interpretation.Acta Geologica Sinica, Vol. 90, July abstract p. 111.Africa, MoroccoPeridotite
DS1993-1388
1993
Algre, C.J.Schiano, P., Algre, C.J., Dupre, B., Lewin, E., Joron, J-L.Variability of trace elements in basaltic suitesEarth and Planetary Science Letters, Vol. 119, No. 1-2, August pp. 37-52GlobalGeochemistry, Basalt
DS200712-0773
2007
AlharthyNasir, S., Al-Khirbashi, S., Al-Sayigh, Alharthy, Mubarek, Rollinson, Lazki, Belouova, Griffin, KaminskyThe first record of allochthonous kimberlite within the Batain Nappes, eastern Oman.Plates, Plumes, and Paradigms, 1p. abstract p. A706.Africa, OmanBatain melange
DS200712-0774
2006
Alharthy, A.Nasir, S., Al-Sayigh, A., Alharthy, A., Al-Lazki, A.Geochemistry and petrology of Tertiary volcanic rocks and related ultramafic xenoliths from the central and eastern Oman Mountains.Lithos, Vol. 90, 3-4, Sept. pp. 249-270.Africa, Arabia, OmanBasanites, xenoliths
DS200812-0787
2008
Al-HarthyNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiEvolved carbonatitic kimberlite from the Batain Nappes, eastern Oman continental margin.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS200812-0788
2008
Al-HarthyNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiLate Jurassic Early Cretaceous kimberlite, carbonatite and ultramafic lamprophyric sill and dyke swarms from the Bomethra area, northeastern Oman.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS201012-0528
2010
Al-HarthyNasir, S., Al-Khirbash, S., Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, A., Theye, T.Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, in press available, 28p.Africa, OmanCarbonatite
DS201112-0724
2011
Al-HarthyNasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, Al-Sayigh, Al-Lazki, Theye, Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp. 47-74.Asia, OmanCarbonatite
DS201112-0723
2011
Al-Harthy, A.Nasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, A., Al-Sayigh, A., Al-Lazki, A.Petrogenesis of early Cretaceous carbonatite and ultramafic lamprophryes in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp.Africa, OmanCarbonatite
DS2002-0021
2002
Al-Heety, E.A.Al-Heety, E.A.Crustal structure of the northern Arabian platform inferred using spectral ratio methodJournal of Geodynamics, Vol. 34, 1,August pp. 63-75.Arabia, North AfricaGeophysics - seismics
DS1995-2048
1995
Alherr, R.Wendlandt, R.F., Alherr, R., Neumann, E., Baldridge, W.S.Methods of investigation: petrology, geochemistry, isotopesContinental Rifts: evolution, structure, tectonics, No. 25, pp. 47-60GlobalMagma, Xenoliths, thermobarometry
DS1995-2049
1995
Alherr, R.Wendlandt, R.F., Alherr, R., Neumann, E., Baldridge, W.S.Methods of investigation: petrology, geochemistry, isotopesContinental Rifts: evolution, structure, tectonics, No. 25, pp. 47-60.GlobalMagma, Xenoliths, thermobarometry
DS1989-1376
1989
AliSharkov, Ye.V., Lazko, Ye.Ye, Fedodosova, S.P., Khanna, S., AliPegmatoid hornblende clinopyroxene xenoliths with barium zeolite from diatremes of northwestern SyriaInternational Geology Review, Vol. 31, No. 4, April pp. 380-386SyriaXenoliths, Diatremes
DS200612-1203
2006
Ali, A.Sahoo, Y.V., Nakai, S., Ali, A.Modified ion exchange separation for tungsten isotopic measurements from kimberlite samples using multi-collector inductivity coupled plama mass spectrometry.Analyst, ( Royal Society of Chemistry), Vol. 131, 3, pp. 434-439.TechnologyGeochemistry
DS200812-0018
2008
Ali, A.Ali, A., Nakai, S., Bell, K., Sahoo, Y.W isotope study of natrocarbonatites from Oldoinyo Lengai Tanzania.Goldschmidt Conference 2008, Abstract p.A15.Africa, TanzaniaCarbonatite
DS201812-2773
2018
Ali, H.Ali, H., Regier, M.E., Pearson, D.G.Increased recovery of diamonds from eclogite by electrical pulse disaggregation. SELFRAG2018 Yellowknife Geoscience Forum , p. 91-92. abstractAfrica, South Africadeposit - Roberts Victor

Abstract: It is well known that mechanical disaggregation, such as jaw crushing, can cause irreversible damage to valuable gemstones hosted in crystalline rocks. The SELFRAG Lab device uses electrical pulses at high voltages - typically between 150 and 200 kV - to separate material into individual grains along natural boundaries. The purpose of this research is to assess the viability of the SELFRAG as a tool to disaggregate diamond-bearing eclogites, and to assess if this method preserves grains that would otherwise be damaged through mechanical disaggregation. In order to test the applicability of the SELFRAG to diamond recovery from mechanically strong diamond-bearing lithologies, we studied its effects on a diamondiferous eclogite, RV09, from Roberts Victor mine. The Roberts Victor mine is located in South Africa and is renowned for its unusually high abundance of mantle-derived eclogite xenoliths1. Before the eclogite was disaggregated, we bisected the sample and used a CT scan to determine its constituent minerals and the spatial distribution of diamond. One half of the sample was then placed into the SELFRAG, where it was subjected to ~100 shots of 200 kV electrical discharges that segregated the sample into individual grains of similar sizes. The other half was jaw crushed, using a steel jaw crusher which produced non-uniform composite grains and abundant fine material. The varying sizes and aggregate pieces made it difficult to pick diamonds, and after no diamonds were found, the jaw-crushed portion underwent further disaggregation in the SELFRAG. After exerting the same time and effort picking through both portions of the RV09 sample, ten diamonds were recovered from the electronically disaggregated portion, while no diamonds were found in the conventionally disaggregated sample. The diamonds released from the SELFRAG were then imaged with a scanning electron microscope (SEM) to determine the extent to which the diamonds were damaged. Most of the released diamonds showed no evidence of breakage, but a few showed signs of damage that may have occurred prior to kimberlite eruption. The dramatic disparity between the number of diamonds recovered with the SELFRAG and the lack of diamonds in the jaw crushed portion indicates that electrical disaggregation is a superior method compared to the conventional mechanical comminution technique. There are little to no signs of breakage in the SELFRAG-liberated diamonds, whereas, the damage caused by jaw crushing was extensive enough to produce small fragments not readily visible via optical microscopy. The SELFRAG is a promising alternative to conventional disaggregation and offers a practical solution for lessening damage to valuable stones in rocks such as eclogites and kimberlites.
DS200512-0011
2005
Ali, J.R.Ali, J.R., Aitchison, J.C.Greater India. 80 year old concept in plate tectonic models of India-Asia collision system.Earth Science Reviews, Vol. 72, 3-4, pp. 169-188.IndiaTectonics, Gondwana, paleogeography
DS200512-0680
2004
Ali, J.R.Malpas, J., Fletcher, C.J.N., Ali, J.R., Aitchison, J.C.Aspects of the tectonic evolution of China.Geological Society of London , Special Publication 226, 368p. $134.ChinaBook - tectonics
DS200612-0013
2005
Ali, J.R.Ali, J.R., Aitchison, J.C.Greater India.Earth Science Reviews, Vol. 72, 3-4, pp. 169-188.IndiaTectonics
DS201212-0338
2012
Ali, J.ZhuJanuszcak, M.H., Seller, S., Kurzlaukis, C., Murphy, J., Delgaty, S., Tappe, K., Ali, J.Zhu, Ellemers, P.A multidisciplinary approach to the Attawapiskat kimberlite field, Canada Canada: accelerating the discovery to production pipeline.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Ontario, AttawapiskatDeposit - Victor
DS201412-0424
2013
Ali, K.Januszczak, N., Seller, M.H., Kurzlaukis, S., Murphy, C., Delgaty, J., Tappe, S., Ali, K., Zhu, J., Ellemers, P.A multidisciplinary approach to the Attwapiskat kimberlite field, Canada: accelerating the discovery-to-production pipeline.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 157-172.Canada, Ontario, AttawapiskatDeposit - Victor area
DS201601-0001
2016
Ali, K.A.Ahmed, A.H., Moghazi, A.K.D., Moufti, M.R., Dawood, Y.H., Ali, K.A.Nature of the lithospheric mantle beneath the Arabian shield and genesis of Al-spinel micropods: evidence from the mantle xenoliths of Harrat Kishb, western Saudi Arabia.Lithos, Vol. 240-243, pp. 119-139.Africa, Saudi ArabiaPeridotite

Abstract: The Harrat Kishb area of western Saudi Arabia is part of the Cenozoic volcanic fields in the western margin of the Arabian Shield. Numerous fresh ultramafic xenoliths are entrained in the basanite lava of Harrat Kishb, providing an opportunity to study the nature and petrogenetic processes involved in the evolution of the lithospheric mantle beneath the Arabian Shield. Based on the petrological characteristics and mineralogical compositions, the majority of the mantle xenoliths (~ 92%) are peridotites (lherzolites and pyroxene-bearing harzburgites); the remaining xenoliths (~ 8%) are unusual spinel-rich wehrlites containing black Al-spinel micropods. The two types of mantle xenoliths display magmatic protogranular texture. The peridotite xenoliths have high bulk-rock Mg#, high forsterite (Fo90-Fo92) and NiO (0.24-0.46 wt.%) contents of olivine, high clinopyroxene Mg# (0.91-0.93), variable spinel Cr# (0.10-0.49, atomic ratio), and approximately flat chondrite-normalized REE patterns. These features indicate that the peridotite xenoliths represent residues after variable degrees of melt extraction from fertile mantle. The estimated P (9-16 kbar) and T (877-1227 °C) as well as the oxidation state (?logfO2 = ? 3.38 to ? 0.22) under which these peridotite xenoliths originated are consistent with formation conditions similar to most sub-arc abyssal-type peridotites worldwide. The spinel-rich wehrlite xenoliths have an unusual amount (~ 30 vol.%) of Al-spinel as peculiar micropods with very minor Cr2O3 content (< 1 wt.%). Olivines of the spinel-rich wehrlites have low-average Fo (Fo81) and NiO (0.18 wt.%) contents, low-average cpx Mg# (0.79), high average cpx Al2O3 content (8.46 wt.%), and very low-average spinel Cr# (0.01). These features characterize early mantle cumulates from a picritic melt fraction produced by low degrees of partial melting of a garnet-bearing mantle source. The relatively high Na2O and Al2O3 contents of cpx suggest that the spinel-rich wehrlites are formed under high P (11-14 kbar), T (1090-1130 °C), and oxidation state (?logfO2 FMQ = + 0.14 to + 0.37), which occurred slightly below the crust-mantle boundary. The REE patterns of spinel-rich wehrlites are almost similar to those of the associated peridotite xenoliths, which confirm at least a spatial genetic linkage between them. Regarding the formation of Al-spinel micropods in spinel-rich wehrlite cumulates, it is suggested that the melt-rock reaction mechanism is not the only process by which podiform chromitite is formed. Early fractionation of picritic melts produced by partial melting of a mantle source under high P-T conditions could be another mechanism. The cpx composition, not opx, as it was assumed, seems to be the main control of the size and composition of spinel concentrations.
DS200712-0008
2007
Ali, M.Ali, M., Arai, S.Clinopyroxene rich lherzolite xenoliths from Bir Ali, Yemen possible product of peridotite/melt reactions.Journal of Mineralogical and Petrological Sciences, Vol. 102, 2, pp. 137-142.MantleLherzolite
DS200612-1569
2005
Ali, S.H.Yelpaala, K., Ali, S.H.Multiple scales of diamond mining in Akwatia, Ghana: addressing environmental and human development impact.Resources Policy, Vol. 30, 3, pp. 145-155.Africa, GhanaSocial environment
DS201810-2300
2018
Ali, S.H.Cartier, L.E., Ali, S.H., Krzemnicki, M.S.Blockchain, chain of custody and trace elements: an overview of tracking and traceability opportunities in the gem industry.The Journal of Gemmology, Vol. 36, 3, pp. 212-227.Globalblockchain terminology
DS201901-0012
2018
Ali, S.H.Cartier, L.E., Ali, S.H., Krzemnicki, M.S.Blockchain, chain of custody and trace elements: an overview of tracking and traceability opoortunities in the gem industry.Journal of Gemmology, Vol. 36, 3, pp. 212-227.Globalblockchain

Abstract: Dr. Laurent Cartier and Dr. Saleem Ali of the Knowledge Hub recently co-authored an overview article on traceability in the gem and jewellery industry. This paper was published in the Journal of Gemmology and is entitled 'Blockchain, Chain of Custody and Trace Elements: An Overview of Tracking and Traceability Opportunities in the Gem Industry'. Recent developments have brought due diligence, along with tracking and traceability, to the forefront of discussions and requirements in the diamond, coloured stone and pearl industries. This article provides an overview of current trends and developments in the tracking and traceability of gems, along with an explanation of the terms used in this context. Further, the article discusses current initiatives in the sector and provides an introduction blockchain concepts.
DS201412-0010
2014
Ali Bouhifd, M.Andrault,D., Pesce, G., Ali Bouhifd, M., Bolfan-Casanova, N., Henot, J-M., Mezouar, M.Melting of basalt at the core-mantle boundary.Science, Vol. 344, no. 6186, pp. 892-895.MantleSubduction
DS201412-0006
2014
Ali Moukadiri, A.Alvarez-Valero, A.M., Jagoutz, O., Stanley, J., Manthei, C., Ali Moukadiri, A., Piasecki, A.Crustal attenuation as a tracer for the emplacement of the Beni Bousera ultramafic massif ( Betico-Rifean belt).Geological Society of America Bulletin, Vol. 126, no. 11/12, pp. 1614-1624.Africa, MoroccoBeniBoussera
DS1992-1626
1992
Ali Sha, M.Waller, M., Ali Sha, M.Advances in drilling technologyTransactions of the Institute of Mining and Metallurgy (IMM), Vol. 101, Sept-Dec, pp. A 166-172GlobalDrilling, Overview of advances
DS1991-0013
1991
Alian WangAlian Wang, Dhamelincourt, P., Lihe Guo, Wuyi Wang, Andi ZhangMicro-structural variations in mantle derived garnetsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 448-450ChinaRaman spectroscopy, Garnets
DS1991-0991
1991
Alian WangLihe Guo, Wuyi Wang, Alian Wang, Andi ZhangIR spectroscopic characters of garnets and spinels - a potential discriminative tool for diamond explorationProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 154-156China, Australia, South AfricaSpectroscopy, Chromites
DS1982-0008
1982
Alibert, C.Alibert, C., Michard, A., Albarede, F.Strontium, Neodymium Isotopes and Trace Element Geochemistry of melilitites from Western Europe.Proceedings of Third International Kimberlite Conference, TERRA, Vol. 2, No. 3, PP. 213-214, (abstract.).GlobalKimberlite, Rare Earth Elements (ree)
DS1983-0006
1983
Alibert, C.Alibert, C., Albaredo, F.Isotopic Heterogeneities in North American KimberlitesEos, Vol. 64, No. 18, MAY 3, P. 341. (abstract.).United StatesBlank
DS1983-0007
1983
Alibert, C.Alibert, C., Michard, A., Albarede, F.The Transition from Alkali Basalts to Kimberlites Isotope And Trace Element Evidence from Melilitites.Contributions to Mineralogy and Petrology, Vol. 82, No. 2-3, PP. 176-186.GlobalPetrology, Petrography
DS1986-0013
1986
Alibert, C.Alibert, C., Michaud, A., Albarede, F.Isotope and trace element geochemistry of Colorado PLateau volcanicsGeochem. et Cosmochem. Acta, Vol.50, No. 12, December pp. 2735-2750ColoradoUSA, Geochemistry
DS1988-0005
1988
Alibert, C.Alibert, C., Albarede, F.Relationships between mineralogical, chemical and isotopic properties of some North American kimberlitesJournal of Geophysical Research, Vol. 93, No. B7, July 10, pp. 7643-7671Colorado, Wyoming, Kentucky, Pennsylvania, KansasArkansaw, Quebec, British Columbia, Lamproite, Alnoite, Kimberl
DS1994-0034
1994
Alibert, C.Alibert, C.Peridotite xenoliths from western Grand Canyon and the Thumb: a probe into subcontinental mantle Colorado.Journal of Geophysical Research, Vol. 99, No. B11, Nov. 10, pp. 21, 605-620.Colorado PlateauXenoliths, Deposit - The Thumb
DS1995-2008
1995
Alibert, C.Volker, F., Holl, A., Alibert, C.Late Miocene to Quaternary volcanics from Serbia and Macedonia.. new lamproite province.Terra Nova, Abstract Vol., p. 336.Serbia, MacedoniaLamproite
DS200412-0021
2004
Alibert, C.Altherr, R., Meyer, H.P., Holl, A., Volker, F., Alibert, C., McCulloch, M.T., Majer, V.Geochemical and Sr Nd Pb isotopic characteristics of Late Cenozoic leucite lamproites from the East European Alpine belt ( MacedContributions to Mineralogy and Petrology, Vol. 147, 1, pp. 58-73.Europe, MacedoniaLamproite, geodynamics
DS1996-0014
1996
Alidibirov, M.Alidibirov, M., Dingwell, D.B.Magma fragmentation by rapid decompressionNature, Vol. 380, No. 6570, Mar 14, pp. 146-148GlobalMagma, Genesis
DS202010-1841
2020
Alifirova, T.Dymshits, A., Sharygin, I., Liu, Z., Korolev, N., Malkovets, V., Alifirova, T., Yakovlev, I., Xu, Y-G.Oxidation state of the lithospheric mantle beneath Komosomolskaya-Magnitnaya kimberlite pipe, Upper Muna field, Siberian craton.Minerals, Vol. 10, 9, 740 10.3390/ min10090740 24p. PdfRussiadeposit - Muna

Abstract: The oxidation state of the mantle plays an important role in many chemical and physical processes, including magma genesis, the speciation of volatiles, metasomatism and the evolution of the Earth’s atmosphere. We report the first data on the redox state of the subcontinental lithospheric mantle (SCLM) beneath the Komsomolskaya-Magnitnaya kimberlite pipe (KM), Upper Muna field, central Siberian craton. The oxygen fugacity of the KM peridotites ranges from ?2.6 to 0.3 logarithmic units relative to the fayalite-magnetite-quartz buffer (?logfO2 (FMQ)) at depths of 120-220 km. The enriched KM peridotites are more oxidized (?1.0-0.3 ?logfO2 (FMQ)) than the depleted ones (from ?1.4 to ?2.6 ?logfO2 (FMQ)). The oxygen fugacity of some enriched samples may reflect equilibrium with carbonate or carbonate-bearing melts at depths >170 km. A comparison of well-studied coeval Udachnaya and KM peridotites revealed similar redox conditions in the SCLM of the Siberian craton beneath these pipes. Nevertheless, Udachnaya peridotites show wider variations in oxygen fugacity (?4.95-0.23 ?logfO2 (FMQ)). This indicates the presence of more reduced mantle domains in the Udachnaya SCLM. In turn, the established difference in the redox conditions is a good explanation for the lower amounts of resorbed diamonds in the Udachnaya pipe (12%) in comparison with the KM kimberlites (33%). The obtained results advocate a lateral heterogeneity in the oxidation state of the Siberian SCLM.
DS201212-0009
2012
Alifirova, T.A.Alifirova, T.A., Pokhilenko, L.N., Ovchinnikov, Y.I., Riches, A.J.V., Taylor, L.A.Petrologic origin of exsolution textures in mantle minerals: evidence in pyroxenitic xenoliths from Yakutia kimberlites.International Geology Review, in press availableRussia, YakutiaPetrology
DS201212-0010
2012
Alifirova, T.A.Alifirova, T.A., Pokhilenko, L.N., Malkovets, V.G., Griffin, W.L.Petrological inferences for the role of exsolution in upper mantle: evidence from the Yakutian kimberlite xenoliths.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractRussia, YakutiaPetrology
DS201212-0559
2012
Alifirova, T.A.Pokhilenko, L.N., Alifirova, T.A., Yudin, D.S.40Ar/39Ar dating of phlogopite of mantle xenoliths from kimberlite pipes of Yakutia: evidence for deep ancient metasomatism of the Siberian platform.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractRussia, YakutiaGeochronology
DS201312-0014
2013
Alifirova, T.A.Alifirova, T.A., Pokhilenko, L.N.Apatite exsolution as an indicator of Udachnaya grospydite UHP history.Goldschmidt 2013, AbstractRussiaUHP
DS201503-0131
2015
Alifirova, T.A.Alifirova, T.A., Pokhilenko, L.N., Korsakov, A.V.Apatite, SiO2, rutile and orthopyroxene precipitates in minerals of eclogite xenoliths from Yakutian kimberlites, Russia.Lithos, Vol. 226, pp. 31-49.Russia, YakutiaDeposit - Udachnaya, Zarnitsa, Obnazhennaya

Abstract: Eclogite mantle xenoliths from the central part of Siberian craton (Udachnaya and Zarnitsa kimberlite pipes) as well as from the northeastern edge of the craton (Obnazhennaya kimberlite) were studied in detail. Garnet and clinopyroxene show evident exsolution textures. Garnet comprises rutile, ilmenite, apatite, and quartz/coesite oriented inclusions. Clinopyroxene contains rutile (± ilmenite) and apatite precipitates. Granular inclusions of quartz in kyanite and garnet usually retain features of their high-pressure origin. According to thermobarometric calculations, studied eclogitic suite was equilibrated within lithospheric mantle at 3.2–4.9 GPa and 813–1080 °C. The precursor composition of garnets from Udachnaya and Zarnitsa eclogites suggests their stability at depths 210–260 km. Apatite precipitation in clinopyroxenes of Udachnaya and Zarnitsa allows us to declare that original pyroxenes could have been indicative of their high P–T stability. Raman spectroscopic study of quartz and coesite precipitates in garnet porphyroblasts confirms our hypothesis on the origin of the exsolution textures during pressure-temperature decrease. With respect to mineralogical data, we suppose the rocks to be subjected to stepwise decompression and cooling within mantle reservoir.
DS201608-1452
2016
Alifirova, T.A.Yudin, D.S., Tomilanko, A.A., Alifirova, T.A., Travin, A.V., Murzintsev, N.G., Pokhilenko, N.P.Results of 40 Ar/39 Ar dating of phlogopites from kelphyphitic rims around garnet grains ( Udachnaya- Vostochnaya pipe).Doklady Earth Sciences, Vol. 469, 1, pp. 728-731.RussiaDeposit - Udachnaya - Vostochnaya
DS201709-1950
2017
Alifirova, T.A.Alifirova, T.A., Pokhilenko, L.N., Taylor, L.A.Evolution of garnet clinopyroxenites from a margin of Siberian craton in major and rare element viewpoint.Goldschmidt Conference, abstract 1p.Russia, Siberiadeposit - Obnazhennaya

Abstract: Clinopyroxenite mantle xenoliths from Obnazhënnaya kimberlite pipe, NE part of Siberian craton (Russia), preserve porphyroclastic clinopyroxene with no less than two generations of garnet and orthopyroxene lamellae, sometimes together with rutile. Their crystallographic relationships are consistent with an origin by solid-state exsolution. According to reintegrated major-element chemistry and datasets for natural systems the homogeneous high-Al clinopyroxenes were previously in equilibrium within a T range of ~1400– 1500 ºC at a minimum P of 2 GPa. Ca and Al variations in a clinopyroxene assume exsolution to take place during a cooling accompanied by a compression. According to Al contents the growth of orthopyroxene lamellae in the rocks is continued down to ~850 ºC and 2.7 GPa. The xenoliths matrix assemblage of Cpx+Grt±Opx marks strain-induced recrystallization where the exsolution features in recrystallized minerals are absent. Later re-equilibration of the mineral assemblage occurred at 790–810 ºC and 3.0–3.2 GPa in the cratonic mantle prior to the removal of rocks by kimberlite melts; the reactions were controlled by the diffusion of Ca and Al in a pyroxene structure. It was noted that Sr in clinopyroxenes (284–556 ppm) increases from core to rim together with V (149–226 ppm) and Ca, opposite to Al content higher in the center of Cpx porphyroclasts. A positive Eu anomaly is significant both in clinopyroxenes and garnets (Eu/Eu* = 1.5–1.8 and 1.3–2.0, respectively). Substitution of Al for Si in the pyroxene tetrahedral sites has allowed charging balance for the substitution of additional trivalent REE into the pyroxene M2 site [1]. The process has affected to the Sr2+, Sm3+ and V3+ contents and Eu2+/Eu3+ relations responsible for the presence of Eu anomaly in a pyroxene. The work was supported by the grant of the President of the Russian Federation MK-2231.2017.5. The study with LAT was funded by NSF grant EAR-1144337.
DS201902-0321
2019
Alifirova, T.A.Spengler, D., Alifirova, T.A.Formation of Siberian cratonic mantle websterites from high Mg magmas.Lithos, Vol. 326-327, pp. 384-396.Russiawebsterites

Abstract: Garnet-(olivine) websterite xenoliths from the lithospheric mantle of the central and northeastern parts of the Siberian Craton contain exsolution microstructures after Si- and Ti-rich precursor garnets. We petrographically, geochemically, and thermobarometrically investigated 13 such xenoliths from the Mir, Obnazhennaya, and Udachnaya kimberlite pipes. All samples contain garnet grains with needle- to lamellae-shaped precipitates (up to 3.0?vol%), including Ti-oxide and/or pyroxene. Orthopyroxene and clinopyroxene grains host oriented lamellae of complementary Ca-rich and Ca-poor pyroxene, respectively, in addition to lamellae of garnet and Ti- and/or Cr-oxides. The common exsolution lamellae assemblages in garnet and pyroxene imply that exsolution occurred during cooling from high-temperature precursors. Exsolution is unlikely to have resulted from variations in pressure, given experimental and thermodynamic constraints. Host mineral partitioning of transition metal and lanthanide elements with different diffusivities record temperatures that range between those of local geotherms and a dry pyroxenite solidus. Inferred magmatic minimum temperatures of 1500-1700?°C satisfy the physical conditions predicted from experimental studies of the solubility of excess Si and Ti in garnet. Granular inclusions of all major minerals within each other imply an overlapping crystallisation history. The reconstructed compositions of the websterite whole-rocks have high MgO contents (15.7-35.7?wt%). A plot of MgO/SiO2 versus SiO2 forms an array, apart from the compositions of natural websterites that formed by interaction of peridotite with basaltic or siliceous melts. The array overlaps the compositional range of komatiite flows from Commondale and Barberton, South Africa, including spinifex, massive, and cumulate subtypes of komatiites. Other major and minor element abundances and ratios of the Siberian websterite suite resemble those of South African Al-enriched komatiites and are distinct from melt-rock reaction websterites. Therefore, the mineral microstructures and geochemistry of the Siberian websterites are suggestive of the former presence of a thermal anomaly. We propose that mantle plume activity or a similar form of lower-mantle ascent played a major role in stabilising cratonic nuclei before amalgamation of the present-day Siberian Craton.
DS201906-1341
2019
Alifirova, T.A.Rezvukhin, D.I., Alifirova, T.A., Korsakov, A.V., Golovin, A.V. A new occurrence pf yimengite-hawthorneite and crichtonite-group minerals on an orthopyroxenite from kimberlite: implications for mantle metasomatism.American Mineralogist, Vol. 104, pp. 761-774.Russiadeposit - Udachnaya-East

Abstract: Large-ion lithophile elements (LILE)-enriched chromium titanates of the magnetoplumbite (AM12O19) and crichtonite (ABC18T2O38) groups have been recognized as abundant inclusions in orthopyroxene grains in a mantle-derived xenolith from the Udachnaya-East kimberlite pipe, Daldyn field, Siberian craton. The studied xenolith consists of three parts: an orthopyroxenite, a garnet clinopyroxenite, and a garnet-orthopyroxene intermediate domain between the two. Within the host enstatite (Mg# 92.6) in the orthopyroxenitic part of the sample titanate inclusions are associated with Cr-spinel, diopside, rutile, Mg-Cr-ilmenite, and pentlandite. Crichtonite-group minerals also occur as acicular inclusions in pyrope grains of the intermediate domain adjacent to the orthopyroxenite, as well as in interstitial to enstatite oxide intergrowths together with Cr-spinel, rutile, and ilmenite. Yimengite-hawthorneite inclusions in enstatite contain (wt%) 3.72-8.04 BaO, 2.05-3.43 K2O, and 0.06-0.48 CaO. Their composition is transitional between yimengite and hawthorneite end-members with most grains exhibiting K-dominant chemistry. A distinct feature of the studied yimengitehawthorneite minerals is a high content of Al2O3 (5.74-7.69 wt%). Crichtonite-group minerals vary in compositions depending on the occurrence in the xenolith: inclusions in enstatite are moderate-high in TiO2 (62.9-67.1 wt%), moderately Cr-rich (12.6-14.0 wt% Cr2O3), Ba- or K-specific in the A site, and contain low ZrO2 (0.05-1.72 wt%), whereas inclusions in pyrope are moderate in TiO2 (61.7-63.3 wt% TiO2), relatively low in Cr (8.98-9.62 wt% Cr2O3), K-dominant in the A site, and are Zr-enriched (4.64-4.71 wt% ZrO2). Crichtonite-group minerals in polymineralic oxide intergrowths show highly diverse compositions even within individual aggregates, where they are chemically dominated by Ba, Ca, and Sr. P-T estimates indicate the orthopyroxenite to have equilibrated at ~800 °C and 35 kbar. Preferentially oriented lamellae of enstatite-hosted Cr-spinel and diopside, as well as pyrope, diopside, and Cr-spinel grains developed around enstatite crystals, are interpreted to have been exsolved from the high-T Ca-Al-Cr-enriched orthopyroxene precursor. The exotic titanate compositions and observed textural relationships between inclusions in enstatite imply that the studied orthopyroxenite has undergone metasomatic processing by a mobile percolating agent afterward; this highly evolved melt/fluid was enriched in Ba, K, HFSE, and other incompatible elements. The infiltration of the metasomatizing liquid occurred through interstices and vulnerable zones of enstatite grains and manifested in the crystallization of titanate inclusions. It is assumed that Cr-spinel lamellae served as seeds for their nucleation and growth. The prominent textural and chemical inhomogeneity of the interstitial oxide intergrowths is either a consequence of the metasomatic oxide crystallization shortly prior to the kimberlite magma eruption or arose from the intensive modification of preexisting oxide clusters by the kimberlite melt during the Udachnaya emplacement. Our new data provide implications for the metasomatic treatment of orthopyroxenites in the subcontinental lithospheric mantle from the view of exotic titanate occurrences.
DS202004-0531
2020
Alifirova, T.A.Rezvukhin, D.I., Alifirova, T.A., Golovin, A.V., Korsakov, A.V.A plethora of epigenetic minerals reveals a multistage metasomatic overprint of a mantle orthopyroxenite from the Udachaya kimberlite.Minerals MDPI, Vol. 10, 10030264. 34p. PdfRussiadeposit - Udachnaya

Abstract: More than forty mineral species of epigenetic origin have been identified in an orthopyroxenite from the Udachnaya-East kimberlite pipe, Daldyn kimberlite field, Siberian platform. Epigenetic phases occur as: (1) Mineral inclusions in the rock-forming enstatite, (2) daughter minerals within large (up to 2 mm) crystallized melt inclusions (CMI) in the rock-forming enstatite, and (3) individual grains and intergrowths in the intergranular space of the xenolith. The studied minerals include silicates (olivine, clinopyroxene, phlogopite, tetraferriphlogopite, amphibole-supergroup minerals, serpentine-group minerals, talc), oxides (several generations of ilmenite and spinel, rutile, perovskite, rare titanates of the crichtonite, magnetoplumbite and hollandite groups), carbonates (calcite, dolomite), sulfides (pentlandite, djerfisherite, pyrrhotite), sulfate (barite), phosphates (apatite and phosphate with a suggested crystal-chemical formula Na2BaMg[PO4]2), oxyhydroxide (goethite), and hydroxyhalides (kuliginite, iowaite). The examined epigenetic minerals are interpreted to have crystallized at different time spans after the formation of the host rock. The genesis of minerals is ascribed to a series of processes metasomatically superimposed onto the orthopyroxenite, i.e., deep-seated mantle metasomatism, infiltration of a kimberlite-related melt and late post-emplacement hydrothermal alterations. The reaction of orthopyroxene with the kimberlite-related melt has led to orthopyroxene dissolution and formation of the CMI, the latter being surrounded by complex reaction zones and containing zoned olivine grains with extremely high-Mg# (up to 99) cores. This report highlights the utility of minerals present in minor volume proportions in deciphering the evolution and modification of mantle fragments sampled by kimberlitic and other deep-sourced magmas. The obtained results further imply that the whole-rock geochemical analyses of mantle-derived samples should be treated with care due to possible drastic contaminations from “hiding” minor phases of epigenetic origin.
DS202008-1437
2020
Alifirova, T.A.Rezvukhin, D.I., Alifirova, T.A., Golovin, A.V., Korsakov, A.V.A plethora of epigenetic minerals reveals a multistage metasomatic overprint of a mantle orthopyroxenite from the Udachnaya kimberlite.MDPI Minerals, Vol. 10, 264, doi.10.3390/ min10030264 34p. PdfRussiadeposit - Udachnaya-East

Abstract: More than forty mineral species of epigenetic origin have been identified in an orthopyroxenite from the Udachnaya-East kimberlite pipe, Daldyn kimberlite field, Siberian platform. Epigenetic phases occur as: (1) Mineral inclusions in the rock-forming enstatite, (2) daughter minerals within large (up to 2 mm) crystallized melt inclusions (CMI) in the rock-forming enstatite, and (3) individual grains and intergrowths in the intergranular space of the xenolith. The studied minerals include silicates (olivine, clinopyroxene, phlogopite, tetraferriphlogopite, amphibole-supergroup minerals, serpentine-group minerals, talc), oxides (several generations of ilmenite and spinel, rutile, perovskite, rare titanates of the crichtonite, magnetoplumbite and hollandite groups), carbonates (calcite, dolomite), sulfides (pentlandite, djerfisherite, pyrrhotite), sulfate (barite), phosphates (apatite and phosphate with a suggested crystal-chemical formula Na2BaMg[PO4]2), oxyhydroxide (goethite), and hydroxyhalides (kuliginite, iowaite). The examined epigenetic minerals are interpreted to have crystallized at different time spans after the formation of the host rock. The genesis of minerals is ascribed to a series of processes metasomatically superimposed onto the orthopyroxenite, i.e., deep-seated mantle metasomatism, infiltration of a kimberlite-related melt and late post-emplacement hydrothermal alterations. The reaction of orthopyroxene with the kimberlite-related melt has led to orthopyroxene dissolution and formation of the CMI, the latter being surrounded by complex reaction zones and containing zoned olivine grains with extremely high-Mg# (up to 99) cores. This report highlights the utility of minerals present in minor volume proportions in deciphering the evolution and modification of mantle fragments sampled by kimberlitic and other deep-sourced magmas. The obtained results further imply that the whole-rock geochemical analyses of mantle-derived samples should be treated with care due to possible drastic contaminations from “hiding” minor phases of epigenetic origin.
DS202010-1840
2020
Alifirova, T.A.Dymshits, A., Sharygin, I., Malkovets, V., Yakovlev, I.V., Gibsher, A.A., Alifirova, T.A., Vorobei, S.S., Potapov, S.V., Garanin, V.K.Thermal state, thickness and composition of the lithospheric mantle beneath the Upper Muna kimberlite field, Siberian Craton, constrained by clinopyroxene xenocrysts and comparison with Daldyn and Mirny fields.Minerals, 10.1039/DOJA00308E 20p. PdfRussiadeposit - Muna

Abstract: To gain better insight into the thermal state and composition of the lithospheric mantle beneath the Upper Muna kimberlite field (Siberian craton), a suite of 323 clinopyroxene xenocrysts and 10 mantle xenoliths from the Komsomolskaya-Magnitnaya (KM) pipe have been studied. We selected 188 clinopyroxene grains suitable for precise pressure (P)-temperature (T) estimation using single-clinopyroxene thermobarometry. The majority of P-T points lie along a narrow, elongated field in P-T space with a cluster of high-T and high-P points above 1300 °C, which deviates from the main P-T trend. The latter points may record a thermal event associated with kimberlite magmatism (a “stepped” or “kinked” geotherm). In order to eliminate these factors, the steady-state mantle paleogeotherm for the KM pipe at the time of initiation of kimberlite magmatism (Late Devonian-Early Carboniferous) was constrained by numerical fitting of P-T points below T = 1200 °C. The obtained mantle paleogeotherm is similar to the one from the nearby Novinka pipe, corresponding to a ~34-35 mW/m2 surface heat flux, 225-230 km lithospheric thickness, and 110-120 thick "diamond window" for the Upper Muna field. Coarse peridotite xenoliths are consistent in their P-T estimates with the steady-state mantle paleogeotherm derived from clinopyroxene xenocrysts, whereas porphyroclastic ones plot within the cluster of high-T and high-P clinopyroxene xenocrysts. Discrimination using Cr2O3 demonstrates that peridotitic clinopyroxene xenocrysts are prevalent (89%) among all studied 323 xenocrysts, suggesting that the Upper Muna mantle is predominantly composed of peridotites. Clinopyroxene-poor or -free peridotitic rocks such as harzburgites and dunites may be evident at depths of 140-180 km in the Upper Muna mantle. Judging solely from the thermal considerations and the thickness of the lithosphere, the KM and Novinka pipes should have excellent diamond potential. However, all pipes in the Upper Muna field have low diamond grades (<0.9, in carats/ton), although the lithosphere thickness is almost similar to the values obtained for the high-grade Udachnaya and Mir pipes from the Daldyn and Mirny fields, respectively. Therefore, other factors have affected the diamond grade of the Upper Muna kimberlite field.
DS202101-0033
2020
Alifirova, T.A.Spengler, D., Alifirova, T.A.Formation of Siberian cratonic mantle websterites from high - Mg magmas.Lithos, in press available 13p. PdfRussiadeposit - Mir, Obnazhennaya, Udachnaya

Abstract: Garnet-(olivine) websterite xenoliths from the lithospheric mantle of the central and northeastern parts of the Siberian Craton contain exsolution microstructures after Si- and Ti-rich precursor garnets. We petrographically, geochemically, and thermobarometrically investigated 13 such xenoliths from the Mir, Obnazhennaya, and Udachnaya kimberlite pipes. All samples contain garnet grains with needle- to lamellae-shaped precipitates (up to 3.0?vol%), including Ti-oxide and/or pyroxene. Orthopyroxene and clinopyroxene grains host oriented lamellae of complementary Ca-rich and Ca-poor pyroxene, respectively, in addition to lamellae of garnet and Ti- and/or Cr-oxides. The common exsolution lamellae assemblages in garnet and pyroxene imply that exsolution occurred during cooling from high-temperature precursors. Exsolution is unlikely to have resulted from variations in pressure, given experimental and thermodynamic constraints. Host mineral partitioning of transition metal and lanthanide elements with different diffusivities record temperatures that range between those of local geotherms and a dry pyroxenite solidus. Inferred magmatic minimum temperatures of 1500-1700?°C satisfy the physical conditions predicted from experimental studies of the solubility of excess Si and Ti in garnet. Granular inclusions of all major minerals within each other imply an overlapping crystallisation history. The reconstructed compositions of the websterite whole-rocks have high MgO contents (15.7-35.7?wt%). A plot of MgO/SiO2 versus SiO2 forms an array, apart from the compositions of natural websterites that formed by interaction of peridotite with basaltic or siliceous melts. The array overlaps the compositional range of komatiite flows from Commondale and Barberton, South Africa, including spinifex, massive, and cumulate subtypes of komatiites. Other major and minor element abundances and ratios of the Siberian websterite suite resemble those of South African Al-enriched komatiites and are distinct from melt-rock reaction websterites. Therefore, the mineral microstructures and geochemistry of the Siberian websterites are suggestive of the former presence of a thermal anomaly. We propose that mantle plume activity or a similar form of lower-mantle ascent played a major role in stabilising cratonic nuclei before amalgamation of the present-day Siberian Craton.
DS201212-0560
2012
Aliflrova, T.A.Pokhilenko, L.N., Aliflrova, T.A., Yudin, D.S.40Ar/39Ar dating of phlogopite of mantle xenoliths from kimberlite pipes of Yakutia: evidence for deep ancient metasomatism of the Siberian platform.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, SiberiaGeochronology
DS201112-0806
2011
Aliforova, T.A.Pokhilenko, L.N., Aliforova, T.A.Plagioclase and apatite from exsolution structures in minerals from mantle xenoliths.Doklady Earth Sciences, Vol. 437, 2, pp. 483-485.MantleMineralogy
DS201212-0011
2012
Aliforova, T.A.Aliforova, T.A., Pokhilenko, L.N., Ovchinnikov, Y.I., Donnelly, C.L., Riches, A.J.V., Taylor, L.A.Petrologic origin of exsolution textures in mantle minerals: evidence in pyroxenite xenoliths from Yakutia kimberlites.International Geology Review, Vol. 54, 9, pp. 1071-1092.RussiaDeposit - Yakutia
DS201112-0013
2011
Aliken, V.Aliken, V., Huismans, R.S., Theulot, C.Three dimensional numerical modeling of upper crustal extensional systems.Journal of Geophysical Research, Vol. 116, B10, B10409.MantleTectonics
DS202110-1609
2021
Alikin, O.Dasari, V., Sharma, A., Marvillet, E., Singh, P., Rudashevsky, V., Alikin, O., Zaveri, V.Liberation of emeralds from micaeous host rocks using electric-pulse dissaggregation vs conventional processing.Journal of Gemmology, Vol. 37, 7, pp. 716-724.Globalemeralds

Abstract: In ore processing, electric-pulse disaggregation (EPD) is used for the liberation of mineral crystals from host rocks. Since 2019, EPD technology has been used exclusively to recover emeralds produced from the Kagem mine in Zambia. This article compares the differences in the recovery of emeralds from micaceous schist host rock at the Kagem mine by EPD technology versus the conventional hand-cobbing method. The amount of emeralds obtained using both methods was similar, but EPD had numerous advantages in terms of liberation speed, ease of performing the process and the characteristics of the liberated emeralds.
DS2002-0022
2002
Alirezaei, S.Alirezaei, S., Cameron, E.M.Mass balance during gabbro amphibolite transition, Bamble sector,implications for petrogenesis, tectonicsLithos, Vol. 60, No. 1-2, pp. 21-45.NorwayTectonics - not specific to diamonds
DS1860-0483
1886
Alis, H.Alis, H.Les Diamants de la CouronneJournal of DES DEBATS, Feb. 13TH.GlobalDiamonds Notable
DS201312-0113
2013
Alisic, L.Burstedde, C., Stadler,G., Alisic, L., Wilcox, L.C., Tan, E.,Gurnis, M., Ghattas, O.Large scale adaptive mantle convection simulation.Geophysical Journal International, Vol. 192, no. 3, pp. 889-906.MantleConvection
DS1860-1052
1899
Alison, M.S.Alison, M.S.On the Origin and Formation of PansGeological Society of South Africa Transactions, Vol. 4, PP. 159-161.Africa, South AfricaGeomorphology
DS201212-0012
2012
Alistic, L.Alistic, L., Gurnis, M., Stadler, G., Burstedde, C., Ghattas, O.Multi scale dynamics and rheology of mantle flow with plates.Journal of Geophysical Research, Vol. 117, B10 B10402MantleTectonics
DS1994-0035
1994
Alkane Exploration N.L.Alkane Exploration N.L.Company profileAlkane Exploration N.L., 16p.AustraliaNews item -corporate profile, Project -Nullagine
DS200812-0787
2008
Al-KhirbashNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiEvolved carbonatitic kimberlite from the Batain Nappes, eastern Oman continental margin.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS200812-0788
2008
Al-KhirbashNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiLate Jurassic Early Cretaceous kimberlite, carbonatite and ultramafic lamprophyric sill and dyke swarms from the Bomethra area, northeastern Oman.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS201012-0528
2010
Al-Khirbash, S.Nasir, S., Al-Khirbash, S., Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, A., Theye, T.Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, in press available, 28p.Africa, OmanCarbonatite
DS201112-0723
2011
Al-Khirbash, S.Nasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, A., Al-Sayigh, A., Al-Lazki, A.Petrogenesis of early Cretaceous carbonatite and ultramafic lamprophryes in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp.Africa, OmanCarbonatite
DS201112-0724
2011
Al-Khirbash, S.Nasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, Al-Sayigh, Al-Lazki, Theye, Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp. 47-74.Asia, OmanCarbonatite
DS200712-0773
2007
Al-Khirbashi, S.Nasir, S., Al-Khirbashi, S., Al-Sayigh, Alharthy, Mubarek, Rollinson, Lazki, Belouova, Griffin, KaminskyThe first record of allochthonous kimberlite within the Batain Nappes, eastern Oman.Plates, Plumes, and Paradigms, 1p. abstract p. A706.Africa, OmanBatain melange
DS1998-0020
1998
Alkim, F.F.Alkim, F.F., Marshak, S.Transamazonian Orogeny in the Southern Sao Francisco Craton region, evidence for Paleoproterozoic ..Precambrian Research, Vol. 90, No. 1-2, June 30, pp. 29-58Brazil, Minas GeraisTectonics, Quadrilatero Ferrifero, Craton
DS2003-0009
2003
Al-Kindi, S.Al-Kindi, S., White, N., Sinha, M., England, R., Tiley, R.Crustal trace of a hot convective sheetGeology, Vol. 31, 3, pp. 207-10.IcelandGeophysics - seismics, Plumes, underplating, convection
DS200412-0017
2003
Al-Kindi, S.Al-Kindi, S., White, N., Sinha, M., England, R., Tiley, R.Crustal trace of a hot convective sheet.Geology, Vol. 31, 3, pp. 207-10.Europe, IcelandGeophysics - seismics Plumes, underplating, convection
DS1992-1003
1992
Alkmim, F.F.Marshak, S., Alkmim, F.F., Jordt-Evangelista, H.Proterozoic crustal extension and the generation of dome and keel structure in an Archean granite-greenstone terraneNature, Vol. 357, No. 6378, June 11, pp. 491-493BrazilTectonics, Greenstone belts
DS1996-0314
1996
Alkmim, F.F.Cunningham, W.D., Marshak, S., Alkmim, F.F.Structural style of basin inversion at mid-crustal levels: two transects in internal zone ...Precambrian Research, Vol. 77, No. 1-2, March 1, pp. 1-16BrazilBrasiliano Aracuai Belt, Structure
DS2001-0013
2001
Alkmim, F.F.Alkmim, F.F., Marshal\k, S., Fonseca, M.A.Assembling West Gondwana in the Neoproterozoic: clues from the Sao Francisco craton region, Brasil.Geology, Vol. 29, No. 4, Apr. pp.319-22.BrazilGondwana, tectonics, Brasiliano orogeny, Craton
DS200512-0407
2004
Alkmim, F.F.Hartmann, L.A.,Milani, E.J., Schobbenhaus, C., Dall'agnol, R., Alkmim, F.F.The stratigraphy of Brazil: a continental scale task.Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 230-9, Vol. 36, 5, p. 532.South America, BrazilCraton, basins
DS200612-0014
2006
Alkmim, F.F.Alkmim, F.F., Marshak, S., Pedrosa Soares, A.C., Peres, G.G., Cruz, S.C., Whittington, A.Kinematic evolution of the Aracuai West Congo in Brazil and Africa: nutcracker tectonics during the Neoproterozoic assembly of Gondwana.Precambrian Research, Vol. 149, 1-2, pp. 43-64.South America, BrazilTectonics - collisional, orogen
DS201212-0124
2012
Alkmim, F.F.Chemale, F., Dussin, I.A., Alkmim, F.F., Martins, M.S., Queiroga, G., Armstrong, R., Santos, M.N.Unravelling a Proterozoic basin history through detrital zircon geochronology: the case of the Esponhaco Supergroup, Minas Gerais, Brazil.Gondwana Research, Vol. 22, 1, pp. 200-206.South America, Brazil, Minas GeraisSan Francisco Congo paleocraton, diamond bearing sequences
DS1860-0126
1871
All the Year RoundAll the Year RoundThirty Days at the Diamond FieldsAll The Year Round., Vol. 5, P. 617.Africa, South AfricaTravelogue
DS2001-0014
2001
AllAfricaAllAfricaConflict diamonds and the global fightAllAfrica.com, Oct. 23, 2p.Africa, Angola, Democratic Republic of CongoNews item, Conflict diamonds
DS2001-0015
2001
AllAfricaAllAfricaOver $ 1 million of embargoed gems leave Angola a dayAllAfrica.com, Oct. 16, 2p.AngolaNews item, Conflict diamonds
DS2001-0016
2001
AllAfricaAllAfricaDiamond dealers still funding Angolan civil war - is it good for?AllAfrica.com, Oct. 18, 2p.AngolaNews item, Conflict diamonds
DS2003-0010
2003
AllAfricaAllAfricaDe Beers to hike price of its rough diamondsDe Beers, April 30, 1p.GlobalNews item, Diamond Trading Company
DS200412-0018
2003
AllAfricaAllAfricaDe Beers to hike price of its rough diamonds.De Beers, April 30, 1p.GlobalNews item Diamond Trading Company
DS1993-0024
1993
Allamandola, L.J.Allamandola, L.J., Sandford, S.A., Tielens, A.G.G.M., Herbst, T.M.Diamonds in dense molecular clouds: a challenge to the standard interstellar medium paradigM.Science, Vol. 260, April 2, pp. 64-66GlobalDiamond formation, Meteoritic
DS1992-0013
1992
Allan, A.D.Allan, A.D., Leitch, E.C.The nature and origin of eclogite blocks in serpentinite from the TamworthBelt, New England Fold Belt, eastern AustraliaAustralian Journal of Earth Sciences, Vol. 39, No. 1 , February pp. 29-35AustraliaTectonics, Eclogite
DS200712-0009
2007
Allan, J.Allan, J.Alluvial diamond miner ... Rockwell Ventures descriptions of properties.Rockwell Diamonds Inc., Feb. 47p.Africa, South Africa, Democratic Republic of CongoNews item - overview
DS200712-0010
2007
Allan, J.Allan, J.Diamonds Africa 2007: diamond export levy and beneficiation.allanhochreiter.co.za, April 23, 29 slidesAfricaPresentation
DS200712-0011
2007
Allan, J.Allan, J.Diamond market outlook for supply and demand.allanhochreiter.co.za, August 43 slidesGlobalPresentation at Kimberley Symposium
DS200812-0019
2008
Allan, J.Allan, J.Diamond Market prices up; prices down? Presentation by AllanHochreiter.Botswana Resource Conference held July 23-24., ppt presentation 36 slidesGlobalOverview diamond market
DS1970-0618
1973
Allan, J.F.Allan, J.F., Cameron, E.M., Durham, C.C.Reconnaissance geochemistry using lake sediments of a 36, 000 sq mile area of northwestern Shield.Geological Survey of Canada (GSC) Paper, No. 72-50Quebec, OntarioGeochemistry
DS1989-0904
1989
Allan, J.F.Luhr, J.F., Allan, J.F., Carmichael, S.E., Nelson, S.A., HasenakaPrimitive calc-alkaline and alkaline rock types From the western Mexican volcanic beltJournal of Geophysical Research, Vol. 94, No. B4, pp. 4515-4530MexicoMinette, basanite, Alkaline rocks
DS1992-0014
1992
Allan, J.F.Allan, J.F.Geology and mineralization of the Kippawa Yrittrium zirconium prospect, Quebec.Exploration and Mining Geology, Vol. 1, pp. 283-95.QuebecRare earth, carbonatite
DS1992-0015
1992
Allan, J.F.Allan, J.F.Geology and mineralization of the Kipawa yttrium zirconium prospect, QuebecThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Exploration and Mining Geology, Vol. 1, No. 3, July pp. 283-296QuebecRare earths, yttrium, zirconiuM., Deposit - Kipawa
DS1996-0015
1996
Allan, J.G.Allan, J.G., Southern P.A.Baseline dat a collectionEnvironmental Management in Australia Minerals and Energy, UNSW Press, pp. 676-685AustraliaMineral processing, Environmental - mining
DS200812-0730
2007
Allan, J.G.McCarthy, T.S., Allan, J.G.A possible new alluvial diamond field related to the Klipspringer kimberlite swarm, South Africa.South African Journal of Geology, Vol. 110, 4, pp. 503-510.Africa, South AfricaDeposit - Klipspringer
DS1995-1854
1995
Allan, L.H.E.Suslick, S.B., Harris, D.P., Allan, L.H.E.SERFIT: an algorithm to forecast mineral trendsComputers and Geosciences, Vol. 21, No. 5, pp. 703-713GlobalComputer program -SERFIT., Economics
DS2003-0170
2003
Allan, N.L.Brooker, R.A., Du, Z., Blundy, J.D., Kelley, S.P., Allan, N.L., Wood, B.J.The zero charge partitioning behaviour of noble gases during mantle meltingNature, No. 6941, June 12, pp. 738-41.MantleBlank
DS200412-0220
2003
Allan, N.L.Brooker, R.A., Du, Z., Blundy, J.D., Kelley, S.P., Allan, N.L., Wood, B.J., Chamorro, E.M., Wartho, J.A., PurtThe zero charge partitioning behaviour of noble gases during mantle melting.Nature, No. 6941, June 12, pp. 738-41.MantleMelt, geochemistry
DS201212-0556
2012
Allan, N.L.Pinilla, C., Davis, S.E., Scott, T.B., Allan, N.L., Blundy, J.D.Interfacial storage of noble gases and oher trace elements in magmatic systems.Earth and Planetary Science Letters, Vol. 319-320, pp. 287-294.MantleBulk silicates
DS1994-1327
1994
Allan, R.Painter, S., Cameron, E.M., Allan, R., Rouse, J.Reconnaissance geochemistry and its environmental relevanceJournal of Geochem. Explor, Vol. 51, No. 3, Sept. pp. 213-246CanadaGeochemistry, Environmental aspects
DS2001-0017
2001
Allan, S.E.Allan, S.E.Regional modern alluvium sampling survey of the Temagami Marten River areaOntario Geological Survey, Northeastern Mineral Symposium, p. 1, abstract.OntarioGeomorphology - till
DS2001-0018
2001
Allan, S.E.Allan, S.E.Project Unit 00-037. Regional modern alluvium sampling survey of the Temagami Marten River area, northeasternOntario Geological Survey Report Activities, OF No. 6051, pp. 34-1-4.Ontario, TemagamiKapuskasing structural zone, Geochemistry - sampling, discoveries, exploration
DS2002-0023
2002
Allaoua Saadi, M.N.Allaoua Saadi, M.N., Machette,K.M., Haller,K.M., Dart, R.L., Bradley, L-A.Map and database of Quaternary faults and lineaments in BrazilU.s. Geological Survey, OF 02-0230 58p $ 76. http://pubs.usgs.gov/of/2002/ofr-BrazilBlank
DS200412-0019
2002
Allaoua Saadi, M.N.Allaoua Saadi, M.N., Machette,K.M., Haller,K.M., Dart, R.L., Bradley, L-A., De Souza, A.M.P.D.Map and database of Quaternary faults and lineaments in Brazil.U.S. Geological Survey, OF 02-0230 58p $ 76.South America, BrazilMap - structure
DS1994-0036
1994
Allard, D.Allard, D., Armstrong, M., Kleingeld, W.J.The need for a connectivity index in mining geostatisticsGeostatistics for the Next Century, pp. 293-302, Selective Mining UnitGlobalGeostatistics, Connectivity Index
DS201312-0229
2013
Allard, G.Dube-Loubert, H., Roy, M., Allard, G., Lamothe, M., Veilette, J.J.Glacial and nonglacial events in the eastern James Bay lowlands, Canada.Canadian Journal of Earth Sciences, Vol. 50, 4, pp. 379-396.Canada, Ontario, QuebecGeomorphology
DS1986-0870
1986
Allard, M.Woods, D.V., Allard, M.Reconnaissance electromagnetic induction study of the Kapuskasing structural zone: implications for lower crustalconductivityPhysics of the Earth and Planetary Interiors, Vol. 42, No. 3, February 28, pp. 135-142OntarioTectonics, Geophysics
DS1986-0871
1986
Allard, M.Woods, D.W., Allard, M.Electromagnetic induction study of the Kapuskasing structural zone using an array of magnetic variometersExploration Geophysics, Geomagnetism in an Australian Setting, Vol. 17, No. 1, March p. 39. (abstract.)OntarioGeophysics, Tectonics
DS200912-0429
2009
Allard, O.Le Roux, V., Bodinier, J-L., Allard, O., O'Reilly, S.Y., Griffin, W.L.Isotopic decoupling during porous melt flow: a case study in the Lherz peridotite.Earth and Planetary Science Letters, Vol. 279, 1-2, pp.76-85.Europe, FranceGeochronology
DS2000-0746
2000
Allard, P.Parello, F., Allard, P., Catani, O.Isotope geochemistry of Pantelleria volcanic fields, Sicily Channel rift: a mantle volatile end member...Earth and Planetary Science Letters, Vol. 180, No. 3-4, pp.325-40.ItalyGeochemistry, Volcanics
DS201611-2149
2016
Allaz, J.Zhang, L., Smyth, J.R., Allaz, J., Kawazoe, T., Jacobsen, S.D., Jin, Z.Transition metals in the transition zone: crystal chemistry of minor element substitution in wadsleyite.American Mineralogist, Vol. 101, pp. 2322-2330.TechnologyWadsleyite

Abstract: As the most abundant solid phase at depths of 410-525 km, wadsleyite constitutes a large geochemical reservoir in the Earth. To better understand the implications of minor element substitution and cation ordering in wadsleyite, we have synthesized wadsleyites coexisting with pyroxenes with 2-3 wt% of either TiO2, Cr2O3, V2O3, CoO, NiO, or ZnO under hydrous conditions in separate experiments at 1300 °C and 15 GPa. We have refined the crystal structures of these wadsleyites by single-crystal X-ray diffraction, analyzed the compositions by electron microprobe, and estimated M3 vacancy concentration from b/a cell-parameter ratios. According to the crystal structure refinements, Cr and V show strong preferences for M3 over M1 and M2 sites and significant substitution up to 2.9 at% at the tetrahedral site (T site). Ni, Co, and Zn show site preferences similar to those of Fe with M1? M3 > M2 > T. The avoidance of Ni, Co, and Fe for the M2 site in both wadsleyite and olivine appears to be partially controlled by crystal field stabilization energy (CFSE). The estimated CFSE values of Ni2+, Co2+, and Zn2+ at three distinct octahedral sites show a positive correlation with octahedral occupancy ratios [M2/(M1+M3)]. Ti substitutes primarily into the M3 octahedron, rather than M1, M2, or T sites. Ti, Cr, and V each have greater solubility in wadsleyite than in olivine. Therefore these transition metal cations may be enriched in a melt or an accessory phase if hydrous melting occurs on upward convection across the wadsleyite-olivine boundary and may be useful as indicators of high-pressure origin.
DS200812-0787
2008
Al-LazkiNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiEvolved carbonatitic kimberlite from the Batain Nappes, eastern Oman continental margin.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS200812-0788
2008
Al-LazkiNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiLate Jurassic Early Cretaceous kimberlite, carbonatite and ultramafic lamprophyric sill and dyke swarms from the Bomethra area, northeastern Oman.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS201112-0724
2011
Al-LazkiNasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, Al-Sayigh, Al-Lazki, Theye, Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp. 47-74.Asia, OmanCarbonatite
DS200712-0774
2006
Al-Lazki, A.Nasir, S., Al-Sayigh, A., Alharthy, A., Al-Lazki, A.Geochemistry and petrology of Tertiary volcanic rocks and related ultramafic xenoliths from the central and eastern Oman Mountains.Lithos, Vol. 90, 3-4, Sept. pp. 249-270.Africa, Arabia, OmanBasanites, xenoliths
DS201012-0528
2010
Al-Lazki, A.Nasir, S., Al-Khirbash, S., Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, A., Theye, T.Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, in press available, 28p.Africa, OmanCarbonatite
DS201112-0723
2011
Al-Lazki, A.Nasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, A., Al-Sayigh, A., Al-Lazki, A.Petrogenesis of early Cretaceous carbonatite and ultramafic lamprophryes in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp.Africa, OmanCarbonatite
DS200412-0020
2004
Al-Lazki, A.I.Al-Lazki, A.I., Sandvol, E., Seber, D., Barazangi, M., Turkelli, N., Mohamad, R.Pn tomographic imaging of mantle lid velocity and anisotropy at the junction of the Arabian, Eurasian and African plates.Geophysical Journal International, Vol. 158, 3, pp. 1024-1040.AfricaGeophysics - seismics, tomography
DS1998-0021
1998
Allbarede, F.Allbarede, F.Reconciling mantle rare gas geochemistry with tomographic evidence of whole mantle convection.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 34-5.MantleGeophysics - seismic, Plate tectonics
DS1998-0022
1998
Allbarede, F.Allbarede, F., Duchene, S.Simulated garnet clinopyroxene geothermometry of eclogites #1Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 33.MantleThermometry, Eclogites
DS200712-0012
2006
Allbright, M.K.Allbright, M.K.Opportunities & danger .. the world in 2006. Praising the GIA. Keynote speaker.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, pp.2-6GlobalEconomics of the future
DS1996-0016
1996
Alldrich, D.J.Alldrich, D.J., et al.SEG on Safari.. technical notes from the MDD/SEG South African field tripheld November 1995Seg Newsletter, No. 25, April, pp. 18-24South AfricaFieldtrip overview
DS1996-0017
1996
Alldrick, D.J.Alldrick, D.J., et al.Notes from the MDD-SEG 1995 South Africa Field TripThe Gangue, No. 51, January pp. 13-18.South Africa, NamibiaOverview, Fieldtrip notes
DS1993-0607
1993
AllegreGwalani, L.G., Rock, N.M.S., Chang, W.J., Fernandez, S., AllegreAlkaline rocks and carbonatites of Amba Dongar and adjacent areas, DeccanMineralogy and Petrology, Vol. 47, No. 2-4, pp. 219-254IndiaCarbonatite
DS2000-0124
2000
AllegreBurton, K.W., Schiano, Birck, Allegre, Dawson, et al.The distribution and behaviour of rhenium and osmium amongst mantle minerals and the age of lithospheric...Earth and Planetary Science Letters, Vol.183, No.1-2, Nov.30, pp.93-106.TanzaniaGeochronology, Mineral chemistry
DS2002-0229
2002
AllegreBurton, K.W., Gannoun, Birck, Allegre, Schiano,AlardThe compatibility of rhenium and osmium in natural olivine and their behaviour during mantle melting...Earth and Planetary Science Letters, Vol.198,1-2,pp.63-76., Vol.198,1-2,pp.63-76.MantleMineralogy - olivine, Basalt genesis
DS2002-0230
2002
AllegreBurton, K.W., Gannoun, Birck, Allegre, Schiano,AlardThe compatibility of rhenium and osmium in natural olivine and their behaviour during mantle melting...Earth and Planetary Science Letters, Vol.198,1-2,pp.63-76., Vol.198,1-2,pp.63-76.MantleMineralogy - olivine, Basalt genesis
DS1990-0112
1990
Allegre, C.Allegre, C.The behaviour of the earth, continental aand seafloor mobilityHarvard University Press, 275p. $ 14.95GlobalBook -ad, Behaviour of the earth
DS2001-0019
2001
Allegre, C.Allegre, C., Manhes, G., Lewin, E.Chemical composition of the Earth and the volatility control on planetary genesis.Earth and Planetary Science Letters, Vol. 185, No. 1-2, Feb.15, pp.49-69.GlobalGeochemistry
DS200512-0319
2005
Allegre, C.Gautheron, C., Moreira, M., Allegre, C.He Ne and Ar composition of the European lithospheric mantle.Chemical Geology, Vol. 217, 1-2, April 15, pp. 97-112.Mantle, Germany, France, AustriaXenoliths, geochemistry, rare gases
DS1975-0866
1978
Allegre, C.J.Shimizu, N., Allegre, C.J.Geochemistry of Transition Elements in Garnet Lherzolite Nodules in Kimberlites.Contributions to Mineralogy and Petrology, Vol. 67, No. 1, PP. 41-50.United States, HawaiiBlank
DS1982-0004
1982
Allegre, C.J.Albarede, F., Weisbrod, A., Allegre, C.J.The Hercynian Lamprophyres of Southeastern Massif; Isotopic reequilibrium of Strontium and Neodynium in a Metamorphic Environment.C.n.r.s. Paris, PP. 11-12. (abstract.)GlobalGeochemistry, Geochronology
DS1985-0547
1985
Allegre, C.J.Prinzhofer, A., Allegre, C.J.Residual Peridotites and the Mechanism of Partial MeltingEarth and Planetary Science Letters, Vol. 74, pp. 251-265GlobalMantle
DS1986-0507
1986
Allegre, C.J.Luck, J.M., Allegre, C.J.Osmium isotopes as petrogenetic and geodynamic tracerEos, Vol. 67, No. 16, April 22, p. 393. (abstract.)GlobalGeochronology
DS1988-0006
1988
Allegre, C.J.Allegre, C.J.Mantle cycling: process and time scalesCrust Mantle recycling at convergence zones, Editors, Hart, S.R., pp. 1-14GlobalMantle
DS1988-0287
1988
Allegre, C.J.Hamelin, B., Allegre, C.J.Lead isotope study of orogenic lherzolite massifsEarth and Planetary Science Letters, Vol. 91, No. 1-2, December pp. 117-131GlobalGeochronology Lherzolite, Mantle
DS1989-1262
1989
Allegre, C.J.Reisberg, L.C., Luck, J.M., Allegre, C.J.The Rhenium- Osmium (Re-Os) systematics of the Ronda ultramafic complexEos, Vol. 70, No. 15, April 11, p. 509. (abstract.)ScotlandUltramafic, Ronda
DS1990-0404
1990
Allegre, C.J.Dia, A., Allegre, C.J., Erlank, A.J.The development of continental crust through geological time: the South african caseEarth and Planetary Science Letters, Vol. 98, No. 1, April pp. 74-89South AfricaCrust, Tectonics
DS1990-0405
1990
Allegre, C.J.Dia, A., Allegre, C.J., Erlank, A.J.The development of continental crust through geologictime: the South african caseEarth and Planetary Science Letters, Vol. 98, No. 1, April pp. 74-89South AfricaMantle, Tectonics
DS1991-1415
1991
Allegre, C.J.Reisberg, L.C., Allegre, C.J., Luck, J-M.The Rhenium- Osmium (Re-Os) systematics of the Ronda ultramafic complex of southern SpainEarth and Planetary Science Letters, Vol. 105, pp. 196-213SpainUltramafic -lherzolite, Layered intrusion
DS1994-0037
1994
Allegre, C.J.Allegre, C.J., Schneider, S.H.The evolution of the earthScientific American, October pp. 66-75GlobalGeologic past
DS1994-0038
1994
Allegre, C.J.Allegre, C.J., Schneider, S.H.The evolution of the EarthSci. American, Oct. pp. 66-75.GlobalBlank
DS1995-0021
1995
Allegre, C.J.Allegre, C.J., Poirier, J.P., Hofmann, A.W.The chemical composition of the earthEarth and Planetary Science Letters, Vol. 134, No. 3-4, Sept. 1, pp. 515-526.GlobalGeochemistry, Composition -chemical
DS1996-0018
1996
Allegre, C.J.Allegre, C.J., Hofman, A., O'Nions, K.The argon constraints on mantle structureGeophysical Research. Letters, Vol. 23, No. 24, Dec. 1, pp. 3555-58.MantleGeochronology
DS1996-0395
1996
Allegre, C.J.Dupre, B., Gaillardet, J., Rousseau, D., Allegre, C.J.Major and trace elements of river borne material: The Congo BasinGeochimica et Cosmochimica Acta, Vol. 60, No. 8, April pp. 1301-1321.Central African RepublicCongo River Basin, Black Rivers, weathering
DS1996-1219
1996
Allegre, C.J.Roybarman, M., Luck, J.M., Allegre, C.J.OS isotopes in orogenic lherzolite massifs and mantle heterogeneitiesChemical Geology, Vol. 130, No. 1-2, Aug. 7, pp. 55-64.MantleGeochronology, Lherzolites
DS1997-0019
1997
Allegre, C.J.Allegre, C.J.Limitation on the mass exchange between the upper and lower mantle; the evolving convection regime of earth.Earth and Planetary Science Letters, Vol. 150, No. 1-2, July pp. 1-6.MantleSubduction, Convection
DS1998-0463
1998
Allegre, C.J.Gannoun, A., Birck, J.L., Bourdon, B., Allegre, C.J.Re Os systematics in orogenic peridotite massifs and contraints on the petrogenesis of pyroxenites.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 496-7.Morocco, Spain, FranceUltramafics, Deposit - Beni Bouzra, Ronda, Lherz
DS2000-0207
2000
Allegre, C.J.David, K., Schiano, P., Allegre, C.J.Assessment of the Zirconium and Hafnium fractionation in oceanic basalts and continental materials during petrogenetic..Earth and Planetary Science Letters, Vol. 178, No. 3-4, May 30, pp. 285-302.GlobalMagmatism, Petrogenesis
DS2002-0024
2002
Allegre, C.J.Allegre, C.J.The evolution of mantle mixingPhilosophical Transactions, Royal Society of London Series A Mathematical, Vol.1800, pp. 2411-32.MantleGeochemistry
DS2002-1056
2002
Allegre, C.J.Millot, R., Gaillardet, J., Dupre, B., Allegre, C.J.The global control of silicate weathering rates and the coupling of physical erosion: new insights from riversEarth and Planetary Science Letters, Vol.196, 1-2, Feb.28, pp.83-98.Northwest Territories, Alberta, Manitoba, Ontario, QuebecGeomorphology
DS2002-1612
2002
Allegre, C.J.Trieloff, M., Kunz, J., Allegre, C.J.Noble gas systematics of the Reunion mantle plume source and the origin of primordial noble gases in Earth's mantle.Earth and Planetary Science Letters, Vol. 200, No. 3-4, pp. 297-313.MantleGeochemistry, Hot spots - plume
DS200412-1313
2004
Allegre, C.J.Millot, R., Allegre, C.J., Gaillardet, J., Roy, S.Lead isotopic systematics of major river sediments: a new estimate of the Pb isotopic composition of the Upper Continental CrustChemical Geology, Vol. 203, 1-2, Jan. 15, pp. 75-90.MantleGeochronology
DS200612-0431
2005
Allegre, C.J.Gautheron, C., Cartigny, P., Moreira, M., Harris, J.W., Allegre, C.J.Evidence for a mantle component shown by rare gases, C and N isotopes in polycrystalline diamonds from Orapa (Botswana).Earth and Planetary Science Letters, Vol. 240, 3-4, Dec. 15, pp. 559-572.Africa, BotswanaMineral chemistry - compositional elements
DS200812-0020
2008
Allegre, C.J.Allegre, C.J., Manhes, G., Gopel, C.The major differentiation of the Earth at - 4.45 Ga.Earth and Planetary Science Letters, Vol. 267, 1-2, pp.386-398.MantlePetrology
DS1998-1034
1998
Allegrem C.J.Moreira, M., Allegrem C.J.Helium neon systematics and the structure of the mantleChemical Geology, Vol. 147, No. 1-2, May 15, pp. 53-60.MantleStructure
DS201705-0806
2017
Allegretta, I.Agrosi, G., Tempesta, G., Mele, D., Allegretta, I., Teranzo, R., Nestola, F.Multi analytical approach for non-destructuve analyses of a diamond from Udachnaya and its trapped inclusions: the first report of (fe, Ni) 1+xS machinawite sulphide in diamonds.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 5374 AbstractRussiaDeposit - Udachnaya

Abstract: The study of diamonds and the mineral inclusions trapped in them is of great interest for Earth science, since they can provide insight about deep mantle conditions and its evolution. The conventional techniques commonly used are destructive and thus do not allow the employment of different methods used simultaneously to obtain integrated and complementary results. Significant information about the growth conditions of diamonds and their inclusions still trapped within them can be preferably obtained by in situ investigation. In this study, we propose a multi-analytical approach, using a set of non-destructive techniques with conventional sources, to investigate one diamond from Udachnaya kimberlite (Siberia, Russia). The combined use of micro-X-ray Tomography, micro-X-ray Fluorescence, X-Ray Powder Diffraction and micro-Raman spectroscopy, allowed us to determine the spatial distribution of the inclusions, their chemical and mineralogical composition and, finally, the paragenetic suite, totally preserving the diamond host. The sample was also studied by means of X-ray Diffraction Topography to characterize the structural defects and to obtain genetic information about the growth history of the diamond. The combination of the different data provided a sort of «mapping» of a diamond. The X-Ray Topographic images show that the sample investigated exhibits plastic deformation. Actually, one set of {111} slip lamellae, corresponding to polysynthetic twinning, affect the whole sample. The tomographic images reveal that the primary inclusions, not observable optically, show a poly-faceted shape corresponding to an assemblage of tiny crystals. The chemical data display that the trapped minerals are mono-sulphides of Fe, Ni. The diagrams obtained by the X-Ray diffraction reveal that the inclusions mainly consist of an assemblage of tiny crystals of pentlandite and pyrrothite. Nevertheless, a thorough analysis of the diffraction data suggests the presence of another mono-sulphide of Fe,Ni: mackinawite. Raman spectra taken on these inclusions confirm, for the first time, the presence of this metastable phase as inclusion in diamond. The genetic implications of these results are discussed.
DS201712-2668
2017
Allegretta, I.Agrosi, G., Tempesta, G., Mele, D., Allegretta, I., Terzano, R., Shirery, S.B., Pearson, G.D., Nestola, F.Non-destructive, multi-method, internal analysis of multiple inclusions in a single diamond: first occurrence of mackinawite ( Fe,Ni)1+xSAmerican Mineralogist, Vol. 102, pp. 2235-2243.Russia, Siberiadeposit - Udachnaya

Abstract: A single gem lithospheric diamond with five sulfide inclusions from the Udachnaya kimberlite (Siberia, Russia) has been analyzed non-destructively to track the growth conditions of the diamond. Sulfides are the most abundant mineral inclusions in many lithospheric diamond crystals and are the most favorable minerals to date diamond crystals by Re-Os isotope systematics. Our investigation used non-destructive, micro-techniques, combining X-ray tomography, X-ray fluorescence, X-ray powder diffraction, and Raman spectroscopy. This approach allowed us to determine the spatial distribution of the inclusions, their chemical and mineralogical composition on the microscale, and, finally, the paragenetic association, leaving the diamond host completely unaffected. The sample was also studied by X-ray diffraction topography to characterize the structural defects of the diamond and to obtain genetic information about its growth history. The X-ray topographic images show that the sample investigated exhibits plastic deformation. One set of {111} slip lamellae, corresponding to polysynthetic twinning, affects the entire sample. Chemical data on the inclusions still trapped within the diamond show they are monosulfide solid solutions of Fe, Ni and indicate a peridotitic paragenesis. Micro-X-ray diffraction reveals that the inclusions mainly consist of a polycrystalline aggregate of pentlandite and pyrrothite. A thorough analysis of the Raman data suggests the presence of a further Fe, Ni sulfide, never reported so far in diamonds: mackinawite. The total absence of any oxides in the sulfide assemblage clearly indicates that mackinawite is not simply a “late” alteration of pyrrhotite and pentlandite due to secondary oxidizing fluids entering diamond fractures after the diamond transport to the surface. Instead, it is likely formed as a low-temperature phase that grew in a closed system within the diamond host. It is possible that mackinawite is a more common phase in sulfide assemblages within diamond crystals than has previously been presumed, and that the percentage of mackinawite within a given sulfide assemblage could vary from diamond to diamond and from locality to locality.
DS201912-2766
2019
Allegretta, I.Agrosi, G., Tempesta, G., Mele, D., Caggiani, MC., Mangone, A., Della Ventura, G., Cestelli-Guidi, M., Allegretta, I., Hutchison, M.T., Nimis, P., Nestola, F.Multiphase inclusions associate with residual carbonate in a transition zone diamond from Juina, Brazil.Lithos, in press available, 31p. pdfSouth America, Brazildeposit - Juina

Abstract: Super-deep diamonds and their mineral inclusions preserve very precious information about Earth’s deep mantle. In this study, we examined multiphase inclusions entrapped within a diamond from the Rio Vinte e um de Abril, São Luiz area (Juina, Brazil), using a combination of non-destructive methods. Micro-Computed X-ray Tomography (?-CXRT) was used to investigate the size, shape, distribution and X-Ray absorption of inclusions and mapping by micro X-ray Fluorescence (?-XRF), ?-Raman Spectroscopy and micro-Fourier Transform Infrared Spectroscopy (?-FTIR) were used to determine the chemical and mineralogical composition of the inclusions. Four large inclusions enclosed in the N-rich diamond core consist of dominant ferropericlase-magnesiowüstite and locally exsolved magnesioferrite. FTIR maps, obtained integrating the band at 1430 cm?1, show also the presence of carbonates. A fifth large inclusion (ca 100 ?m) was remarkable because it showed a very unusual flask shape, resembling a fluid/melt inclusion. Based on ?CXRT tomography and ?-Raman mapping, the flask-shaped inclusion is polyphase and consists of magnetite and hematite partly replacing a magnesiowüstite core and small-volume of gas/vacuum. ?-Raman spectra on the same inclusion revealed local features that are ascribed to post-spinel polymorphs, such as maohokite or xieite, which are stable at P ? 18 GPa, and to huntite, a carbonate with formula CaMg3(CO3)4. This represents the first finding of maohokite and huntite in diamond. We interpret the composition of the inclusions as evidence of formation of ferropericlase-magnesiowüstite and diamond in a carbonate-rich environment at depths corresponding at least to the Transition Zone, followed by oxidation of ferropericlase-magnesiowüstite by reaction with relatively large-volume entrapped melt during diamond ascent.
DS200812-0021
2008
Allek, K.Allek, K., Hamoudi, M.Regional scale aeromagnetic survey of the south-west of Algeria: a tool for area selection for diamond exploration.Journal of African Earth Sciences, Vol. 50, no. 2, Feb. pp. 67-78.Africa, AlgeriaGeophysics - magnetics
DS200612-0024
2006
Alleman, L.Y.Andre, L., Cardinal, D., Alleman, L.Y., Moorbath, S.Silicon isotopes in ~3.8 Ga West Greenland rocks as clues to the Eoarchean supracrustal Si cycle.Earth and Planetary Science Letters, Vol. 245, 1-2, pp. 162-173.Europe, GreenlandGeochronology, silica
DS2002-0405
2002
AllemandDromart, G., Garcia, J.P., Allemand, Gaumet, RouselleA volume based approach to calculation of ancient carbonate accumulationsJournal of Geology, Vol.110,1,pp. 195-210.GlobalCarbonate - overview deposit rates, Phanerozoic - exogenic systems
DS2001-1042
2001
Allemand, P.Schwartz, S., Allemand, P., Guillot, S.Numerical model of the effect of serpentinites on the exhumation of eclogitic rocks: insights from...Tectonophysics, Vol. 342, No. 2, pp. 193-206.AlpsMonviso ophiolitic complex, Eclogites
DS1991-1135
1991
Allen, B.M.Merriam, D.F., Allen, B.M.Color unlocks perspective for 3-D stratigraphic modelsGeotimes, Vol. 36, No. 7, July pp. 19-21GlobalComputers, Color 3-D stratigraphy
DS200612-0085
2006
Allen, C.Barnes, C.G., Li, Y., Barnes, M., McCullock, L., Frost, C., Prestvik, T., Allen, C.Carbonate assimilation in the alkaline Hortavaer igneous complex, Norway.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1. abstract only.Europe, NorwayCarbonatite
DS201212-0105
2012
Allen, C.Campbell, I., Gill, J., Iizuka, T., Allen, C.What detrital zircons tell us about growth of the continental crust.Goldschmidt Conference 2012, abstract 1p.MantleGeochronology
DS201412-0092
2014
Allen, C.Campbell, I., Stepanov, A., Liang, H-Y., Allen, C., Norman, M., Zhang, Y-Q, Xie, Y-W.The origin of shoshonites: new insights from the Tertiary high-potassium intrusions of eastern Tibet.Contributions to Mineralogy and Petrology, Vol. 167, 3, pp. 1-22.Asia, TibetShoshonite
DS200712-1194
2006
Allen, C.M.Xu, C., Campbell, I.H., Allen, C.M., Huang, Z., Qi, L., Zhang, H., Zhang, G.Flat rare earth element patterns as an indicator of cumulate processes in the Lesser Qinlin carbonatites, China.Geochimica et Cosmochimica Acta, In press availableChinaCarbonatite, REE geochemistry
DS200912-0820
2009
Allen, C.M.Witt-Eickschen, G., Palme, H., O'Neill, H.St.C., Allen, C.M.The geochemistry of the volatile trace elements As, Cd, Ga, In and Sn in the Earth's mantle: new evidence from in situ analyses of mantle xenoliths.Geochimica et Cosmochimica Acta, Vol. 73, 6, pp. 1755-1778.MantleGeochemistry
DS201312-0432
2013
Allen, C.M.Izuka, T., Campbell, I.H., Allen, C.M., Gill, J.B., Maruyama, S., Makota, F.Evolution of the African continental crust as recorded by U-Pb, Lu-Hf and O isotopes in detrital zircons from modern rivers.Geochimica et Cosmochimica Acta, Vol. Pp. 96-120.AfricaGeochronology, Comgo, Zambesi, Orange
DS201711-2528
2017
Allen, C.M.Siegel, C., Bryan, S.E., Allen, C.M.Use and abuse of zircon based thermometers: a critical review and a recommended approach to identify antecrystic zircons.Earth-Science Reviews, Vol. 176, pp. 87-116.Technologygeothermometry

Abstract: Zircon- and bulk-rock Zr-based thermometric parameters have become fundamental to petrogenetic models of magmatism, from which broader geochronological and tectonic implications are being made. In particular, petrogenetic models have become increasingly reliant on Ti concentration in zircon geothermometry (TZircTi) and zircon saturation temperature (TZircsat). A feature of many of these studies is an implicit assumption that all zircons present in the host igneous rock are autocrystic, that is, crystallised from the surrounding melt. However, it has long been recognised that zircons present in an igneous rock can be inherited either from the surrounding country rock or source region (xenocrysts), or from earlier phases of magmatism or the magmatic plumbing system (antecrysts). Distinguishing these different origins for zircon crystals or domains within crystals is not straightforward. Here, we first review the utility and reliability of zircon-based thermometers for petrogenetic studies and show that TZircsat is a theoretical temperature and cannot be used to constrain magmatic or partial melting temperatures. It is a dynamic variable that changes during magma crystallisation, and essentially increases as fractional crystallisation proceeds, whereas true magmatic temperatures (TMagma) decrease. Generally, in Temperature-SiO2 space, the cross-over point of these two temperatures is magmatic system dependent, and also affected by the type of calibration used for the TZircsat calculations. Consequently, each magmatic system needs to be evaluated independently to assess the validity and usefulness of TZircsat. A fundamental conclusion of TZircsat and TMagma relationships assessed here is that new zircon generally only crystallises in silicic (granitic/rhyolitic) melt compositions, and thus autocrystic zircons should not be assumed to be present in igneous rocks with bulk compositions < 64 wt% SiO2, although inherited and minor zircons crystallising from late-stage differentiated melt pockets can be present. This highlights the importance of discriminating autocrystic from inherited zircons in igneous rocks. We then review techniques available to discriminate autocrystic from inherited zircons, and propose a new methodology to assist in the identification of autocrystic zircons for emplacement age determination and separate evaluation of inherited zircon components. The approach uses two strands of data: 1) zircon data such as zircon morphologies, textures, compositions and U-Pb ages, and 2) whole-rock data, in particular SiO2 and coupled geothermometry (TZircsat and TMagma) to estimate whether the magma was zircon-saturated or undersaturated. To test this new protocol, we use as examples, several Phanerozoic granitic rocks intersected by drilling in Queensland where contextual information is limited, and show how antecrystic and xenocrystic zircons and monazites can be distinguished. In contrast, where zircons are metamict (for example, high U and Th-rich zircons), much of the ability to discriminate is impacted because such zircons have suffered Pb loss and have modified compositions (e.g., higher TZircTi). We recommend an integrated approach incorporating whole-rock chemistry, independent geothermometric constraints, zircon composition, textures and ages obtained by routine cathodoluminescence and LA-ICP-MS or ion microprobe analysis to provide increased confidence for the discrimination of inherited zircons from autocrystic zircons and determination of the emplacement age.
DS201712-2730
2017
Allen, C.M.Siegel, C., Bryan, S.E., Allen, C.M., Gust, D.A.Use and abuse of zircon based thermometers: a critical review and recommended approach to identify antecrystic zircons.Earth Science Reviews, Vol. 176, 10.1016Technologygeothermometry

Abstract: Zircon- and bulk-rock Zr-based thermometric parameters have become fundamental to petrogenetic models of magmatism, from which broader geochronological and tectonic implications are being made. In particular, petrogenetic models have become increasingly reliant on Ti concentration in zircon geothermometry (TZircTi) and zircon saturation temperature (TZircsat). A feature of many of these studies is an implicit assumption that all zircons present in the host igneous rock are autocrystic, that is, crystallised from the surrounding melt. However, it has long been recognised that zircons present in an igneous rock can be inherited either from the surrounding country rock or source region (xenocrysts), or from earlier phases of magmatism or the magmatic plumbing system (antecrysts). Distinguishing these different origins for zircon crystals or domains within crystals is not straightforward. Here, we first review the utility and reliability of zircon-based thermometers for petrogenetic studies and show that TZircsat is a theoretical temperature and cannot be used to constrain magmatic or partial melting temperatures. It is a dynamic variable that changes during magma crystallisation, and essentially increases as fractional crystallisation proceeds, whereas true magmatic temperatures (TMagma) decrease. Generally, in Temperature-SiO2 space, the cross-over point of these two temperatures is magmatic system dependent, and also affected by the type of calibration used for the TZircsat calculations. Consequently, each magmatic system needs to be evaluated independently to assess the validity and usefulness of TZircsat. A fundamental conclusion of TZircsat and TMagma relationships assessed here is that new zircon generally only crystallises in silicic (granitic/rhyolitic) melt compositions, and thus autocrystic zircons should not be assumed to be present in igneous rocks with bulk compositions < 64 wt% SiO2, although inherited and minor zircons crystallising from late-stage differentiated melt pockets can be present. This highlights the importance of discriminating autocrystic from inherited zircons in igneous rocks. We then review techniques available to discriminate autocrystic from inherited zircons, and propose a new methodology to assist in the identification of autocrystic zircons for emplacement age determination and separate evaluation of inherited zircon components. The approach uses two strands of data: 1) zircon data such as zircon morphologies, textures, compositions and U-Pb ages, and 2) whole-rock data, in particular SiO2 and coupled geothermometry (TZircsat and TMagma) to estimate whether the magma was zircon-saturated or undersaturated. To test this new protocol, we use as examples, several Phanerozoic granitic rocks intersected by drilling in Queensland where contextual information is limited, and show how antecrystic and xenocrystic zircons and monazites can be distinguished. In contrast, where zircons are metamict (for example, high U and Th-rich zircons), much of the ability to discriminate is impacted because such zircons have suffered Pb loss and have modified compositions (e.g., higher TZircTi). We recommend an integrated approach incorporating whole-rock chemistry, independent geothermometric constraints, zircon composition, textures and ages obtained by routine cathodoluminescence and LA-ICP-MS or ion microprobe analysis to provide increased confidence for the discrimination of inherited zircons from autocrystic zircons and determination of the emplacement age.
DS201802-0280
2017
Allen, C.M.Wong, J., Verdel, C., Allen, C.M.Trace element compositions of sapphire and ruby from the eastern Australian gemstone belt.Mineralogical Magazine, Vol. 81, 6, pp. 1551-1576.Australiamineralogy

Abstract: View at publisher (open access) Abstract Significant uncertainty surrounds the processes involved in the formation of basalt-hosted corundum, particularly the role that the mantle plays in corundum generation. Some previous studies have suggested that trace-element ratios (namely, Cr/Ga and Ga/Mg) are useful for distinguishing two types of corundum: “magmatic” and “metamorphic,” designations that include mantle and crustal processes. However, recent studies, including this one, have discovered transitional groups between these end-members that are difficult to classify. We used LA-ICP-MS to measure trace-element concentrations in sapphire and ruby crystals from eight alluvial deposits that span a significant length of the eastern Australian gemstone belt. Additionally, we collected LA-ICP-MS U-Pb and trace-element data from zircon megacrysts at Weldborough, Tasmania, which is also within the gemstone belt. Our sapphire and ruby results reveal a continuum in trace-element compositions, a finding that raises questions about previous classifications that ascribe corundum from basalt-hosted gemfields to either “magmatic” or “metamorphic” sources. The spatial association of basalt-related gemfields in eastern Australia with a long-lived convergent margin suggests a link between corundum formation and Al-enrichment of the mantle wedge during periods of subduction.
DS201804-0753
2018
Allen, C.M.Wong, J., Verdel, C., Allen, C.M.Trace element compositions of sapphire and ruby from the eastern Australian gemstone belt.Mineralogical Magazine, Vol. 81, 6, pp. 1551-1576.Australia, Tasmaniacorundum classification

Abstract: Significant uncertainty surrounds the processes involved in the formation of basalt-hosted corundum, particularly the role that the mantle plays in corundum generation. Some previous studies have suggested that trace-element ratios (namely, Cr/Ga and Ga/Mg) are useful for distinguishing two types of corundum: ‘magmatic’ and ‘metamorphic’, designations that include mantle and crustal processes. However, recent studies, including this one, have discovered transitional groups between these end-members that are difficult to classify. We used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to measure trace-element concentrations in sapphire and ruby crystals from eight alluvial deposits that span a significant length of the eastern Australian gemstone belt. Additionally, we collected LA-ICP-MS U-Pb and trace-element data from zircon megacrysts at Weldborough, Tasmania, which is also within the gemstone belt. Our sapphire and ruby results reveal a continuum in trace-element compositions, an observation that raises questions regarding previous classifications that ascribe corundum from basalt-hosted gemfields to either ‘magmatic’ or ‘metamorphic’ sources. The spatial association of basalt-related gemfields in eastern Australia with a long-lived convergent margin suggests a link between corundum formation and Al-enrichment of the mantle wedge during periods of subduction.
DS201806-1260
2018
Allen, C.M.Wiemar, D., Schrank, C.E., Murphy, D.T., Wenham, L., Allen, C.M.Earth's oldest stable crust in the Pilbara craton formed by cyclic gravitational overturns.Nature , Vol. 11, 5, pp. 357-361.Australiageophysics

Abstract: During the early Archaean, the Earth was too hot to sustain rigid lithospheric plates subject to Wilson Cycle-style plate tectonics. Yet by that time, up to 50% of the present-day continental crust was generated. Preserved continental fragments from the early Archaean have distinct granite-dome/greenstone-keel crust that is interpreted to be the result of a gravitationally unstable stratification of felsic proto-crust overlain by denser mafic volcanic rocks, subject to reorganization by Rayleigh-Taylor flow. Here we provide age constraints on the duration of gravitational overturn in the East Pilbara Terrane. Our U-Pb ages indicate the emplacement of ~3,600-3,460-million-year-old granitoid rocks, and their uplift during an overturn event ceasing about 3,413?million years ago. Exhumation and erosion of this felsic proto-crust accompanied crustal reorganization. Petrology and thermodynamic modelling suggest that the early felsic magmas were derived from the base of thick (~43?km) basaltic proto-crust. Combining our data with regional geochronological studies unveils characteristic growth cycles on the order of 100?million years. We propose that maturation of the early crust over three of these cycles was required before a stable, differentiated continent emerged with sufficient rigidity for plate-like behaviour.
DS1995-0022
1995
Allen, C.R.Allen, C.R.Geology and due diligenceProspectors and Developers Association of Canada (PDAC) Short Course, March 4, pp. 56-76GlobalDue diligence, Geology -Ore reserves
DS1900-0141
1903
Allen, C.V.Allen, C.V.Mechanical Equipment at KimberleyEng. Magazine., MARCHAfrica, South AfricaMining Recovery
DS1900-0142
1903
Allen, C.V.Allen, C.V.Diamond Mining in the Kimberley FieldEng. Magazine, Vol. 26, No. 10, PP. 81-98; PP. 177-192. ALSO: NEW YORK: WESAfrica, South AfricaMining Engineering, Diamond Recovery
DS1991-0014
1991
Allen, D.J.Allen, D.J., Hinze, W.J.The origin and significance of the Wisconsin gravity minimuMGeological Society of America, Abstract Volume, Vol. 23, No. 3, March p. 1WisconsinGeophysics -gravity, Tectonics
DS1992-0016
1992
Allen, D.J.Allen, D.J., Chandler, V.W.The utility of high-resolution aeromagnetic dat a for investigating The midcontinent Rift in east-central MinnesotaInstitute on Lake Superior Geology, 38th. annual meeting held Hurley, Vol. 38, No. 1, pp. 3-5MinnesotaGeophysics, Midcontinent rift
DS1992-0017
1992
Allen, D.J.Allen, D.J., Hinze, W.J.Wisconsin gravity minimum: solution of a geologic and geophysical puzzle and implications for cratonic evolutionGeology, Vol. 20, No. 6, June pp. 515-518WisconsinGeophysics -gravity, Craton
DS1992-0710
1992
Allen, D.J.Hinze, W.J., Allen, D.J., Fox, A.J., Sunwood, D., Woelk, T., GreenGeophysical investigations and crustal of the North American Midcontinent rift systemTectonophysics, Vol. 213, No. 1-2, special issue, pp. 17-32MidcontinentTectonics, Geophysics
DS1992-0711
1992
Allen, D.J.Hinze, W.J., Allen, D.J., Mariano, J.Lithosphere of the Midcontinent Rift region: progress and problemsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 319MidcontinentMidcontinent Rift, Lithosphere
DS1995-0023
1995
Allen, D.J.Allen, D.J., Braile, L.W., Hinze, W.J., Mariano, J.The midcontinent rift system United States (US): a major Proterozoic continental riftContinental Rifts: evolution, structure, tectonics, No. 25, pp. 375-408Michigan, Wisconsin, Kansas, Lake Superior regionGeophysics - seismics, gravity, Structure
DS1995-0024
1995
Allen, D.J.Allen, D.J., Braile, L.W., Hinze, W.J., Mariano, J.The midcontinent rift system United States (US): a major Proterozoic continental riftContinental Rifts: evolution, structure, tectonics, No. 25, pp. 375-408.Michigan, Wisconsin, Kansas, Lake Superior regionGeophysics - seismics, gravity, Structure
DS1995-0803
1995
Allen, D.J.Hinze, W.J., Allen, D.J., Braile, L.W., Mariano, J.The Midcontinent rift system: an overviewBasement Tectonics 10, held Minnesota Aug 92, pp. 3-6.MidcontinentTectonics
DS1860-0684
1891
Allen, G.Allen, G.Democracy and DiamondsContemporary Review., Vol. 59, P. 666-677.Africa, 'South AfricaPolitics, History
DS1981-0004
1981
Allen, H.E.K.Allen, H.E.K.Development of Orapa and Lethlakane Diamond Mines BotswanaInstitute of Mining and Metallurgy. Transactions, Vol. 90, SECT. A, PP. A177-A191.BotswanaKimberlite
DS1982-0009
1982
Allen, H.E.K.Allen, H.E.K.Some Diamond Mining and Recovery MethodsInstitute of Mining and Metallurgy. Transactions, Vol. 91, SECT. A, JULY, PP. A122-A126.Southwest Africa, South Africa, NamibiaKimberlite, Recovery, Alluvial, Treatment, Mining
DS1984-0008
1984
Allen, H.E.K.Allen, H.E.K.Introduction of Management Objectives at Orapa and Letlhakane Diamond Mines, Botswana: the Transition from Project to Operation.Royal School of Mines, 19P. REVISED Nov. 26TH.BotswanaBlank
DS1960-0003
1960
Allen, H.F.Allen, H.F.Mining a Vertical Kimberlite Fissure at Star Diamond Proprietary Limited.South African Institute of Mining and Metallurgy. Journal, Vol. 61, PP. 310-318.South AfricaMining Methods, Recovery, Evaluation, Placers, Alluvial, Samplin
DS1950-0458
1959
Allen, J.B.Bloxam, T.W., Allen, J.B.Glaucophane Schist, Eclogite and Associated Rocks from Knock normal in the Girvan Ballantrae Complex, South Ayrshire.Royal Society. EDINBURGH Transactions, Vol. 64, PP. 1-28.ScotlandRelated Rocks
DS1960-0051
1960
Allen, J.B.Grantham, D.R., Allen, J.B.Kimberlites in Sierra LeoneOverseas Geol. Min. Res., Vol. 8, PP. 5-25.Sierra Leone, West Africa, KoiduGeology
DS1960-0052
1960
Allen, J.B.Grantham, D.R., Allen, J.B.Kimberlite in Sierra LeoneGeological Survey SIERRA LEONE SHORT PAPER., No. 6West Africa, Sierra LeoneGeology, Petrography
DS1960-0316
1963
Allen, J.B.Allen, J.B.The Identification of Eight Rocks from the Bobi and Sodiamci Areas, Ivory Coast Republic.Overseas Geological Survey Report, No. 128.West Africa, Ivory CoastKimberlite, Petrography
DS1960-0510
1965
Allen, J.B.Allen, J.B., Deans, T.Ultrabasic Eruptives with Alnoitic Kimberlitic Affinities from Malaita solomon Islands.Mineralogical Magazine., Vol. 34, TILLEY VOLUME, PP. 16-34.GlobalRelated Rocks, Indicator Minerals, Mineralogy
DS1950-0163
1954
Allen, J.F.Allen, J.F., Balk, R.Mineral Resources of the Fort Defiance and Tohatchi Quadrangles.New Mexico Bureau of Mines Min. Res. Bulletin., No. 36, 192P.GlobalDiatreme
DS1982-0274
1982
Allen, J.M.Higgins, M.D., Allen, J.M.Carbonate Rich Basalt, Andesite and Dacite Associated with Nephelinites from Northwest British Columbia.Geological Society of America (GSA), Vol. 14, No. 7, P. 514. (abstract.).Canada, British ColumbiaBlank
DS1985-0285
1985
Allen, J.M.Higgins, H., Allen, J.M.A New Locality for Primary Xenolith Bearing Nephelinites In northwestern british ColumbiaCanadian Journal of Earth Sciences, Vol. 22, No. 10, pp. 1556-1559British ColumbiaBlank
DS1985-0286
1985
Allen, J.M.Higgins, M.D., Allen, J.M.A New Locality for Primary Xenolith Bearing Nephelinites In northwestern British Columbia.Canadian Journal of Earth Sciences., Vol. 22, No. 10, OCTOBER PP. 1556-1559.Canada, British ColumbiaNephelinite
DS1988-0253
1988
Allen, L.E.Gershon, M., Allen, L.E., Manley, G.Application of a new approach for drillholes location optimizationInternational Journal of Surface Mining, Vol. 2, pp. 27-31. Database # 17471GlobalDrilling, Geostatistics
DS1993-1744
1993
Allen, M.B.Windley, B.F., Allen, M.B.Mongolian plateau: evidence for a late Cenozoic mantle plume under centralAsia.Geology, Vol. 21, No. 4, April pp. 295-298.GlobalMantle plume, Rifting, Tectonics
DS201412-0959
2014
Allen, M.B.Wang, H., Van Hunen, J., Pearson, D.G., Allen, M.B.Craton stability and longevity: the roles of composition- dependent rheology and buoyancy.Earth and Planetary Science Letters, Vol. 391, 1, pp. 224-233.MantleCraton
DS201709-2027
2017
Allen, M.B.Magni, V., Allen, M.B., van Hunen, J., Bouihol, P.Continental underplating after slab break-off.Earth and Planetary Science Letters, Vol. 474, pp. 59-67.Mantle, India-Eurasiasubduction

Abstract: We present three-dimensional numerical models to investigate the dynamics of continental collision, and in particular what happens to the subducted continental lithosphere after oceanic slab break-off. We find that in some scenarios the subducting continental lithosphere underthrusts the overriding plate not immediately after it enters the trench, but after oceanic slab break-off. In this case, the continental plate first subducts with a steep angle and then, after the slab breaks off at depth, it rises back towards the surface and flattens below the overriding plate, forming a thick horizontal layer of continental crust that extends for about 200 km beyond the suture. This type of behaviour depends on the width of the oceanic plate marginal to the collision zone: wide oceanic margins promote continental underplating and marginal back-arc basins; narrow margins do not show such underplating unless a far field force is applied. Our models show that, as the subducted continental lithosphere rises, the mantle wedge progressively migrates away from the suture and the continental crust heats up, reaching temperatures >900?°C. This heating might lead to crustal melting, and resultant magmatism. We observe a sharp peak in the overriding plate rock uplift right after the occurrence of slab break-off. Afterwards, during underplating, the maximum rock uplift is smaller, but the affected area is much wider (up to 350 km). These results can be used to explain the dynamics that led to the present-day crustal configuration of the India–Eurasia collision zone and its consequences for the regional tectonic and magmatic evolution.
DS201908-1821
2019
Allen, M.B.Wang, C., Song, S., Wei, C., Su, L., Allen, M.B., Niu, Y., Li, X-H., Dong, J.Paleoarchean deep mantle heterogeneity recorded by enriched plume remnants.Nature Geoscience, doi.org/10.1038/s41561-019-0410-y 10p pdfMantlePlumes, hotspots

Abstract: The thermal and chemical state of the early Archaean deep mantle is poorly resolved due to the rare occurrences of early Archaean magnesium-rich volcanic rocks. In particular, it is not clear whether compositional heterogeneity existed in the early Archaean deep mantle and, if it did, how deep mantle heterogeneity formed. Here we present a geochronological and geochemical study on a Palaeoarchaean ultramafic-mafic suite (3.45-Gyr-old) with mantle plume signatures in Longwan, Eastern Hebei, the North China Craton. This suite consists of metamorphosed cumulates and basalts. The meta-basalts are iron rich and show the geochemical characteristics of present-day oceanic island basalt and unusually high mantle potential temperatures (1,675?°C), which suggests a deep mantle source enriched in iron and incompatible elements. The Longwan ultramafic-mafic suite is best interpreted as the remnants of a 3.45-Gyr-old enriched mantle plume. The first emergence of mantle-plume-related rocks on the Earth 3.5-3.45?billion years ago indicates that a global mantle plume event occurred with the onset of large-scale deep mantle convection in the Palaeoarchaean. Various deep mantle sources of these Palaeoarchaean mantle-plume-related rocks imply that significant compositional heterogeneity was present in the Palaeoarchaean deep mantle, most probably introduced by recycled crustal material.
DS1990-0212
1990
Allen, M.S.Bliss, J.D., McKelvey, G.E., Allen, M.S.Application of grade and tonnage deposit models: the search for ore deposits possible amenable to small scale miningUnited States Geological Survey (USGS) Open File, No. 90-0412, 24p. $ 3.75GlobalReserves -Models -grade and tonnage, Mining applications
DS1992-0134
1992
Allen, M.S.Bliss, J.D., Sutphin, D.M., Mosier, D.L., Allen, M.S.Grade and tonnage and target area models of Au-Ag-Te veins associated with alkalic rocksUnited States Geological Survey (USGS) Open File, No. 92-0208, $ 2.25United StatesAlkaline rocks, Mineralization -not specific to kimberlites
DS1994-0734
1994
Allen, P.A.Hartley, R.W., Allen, P.A.Interior cratonic basins of Africa: relation to continental break up and role of mantle convection.Basin Research, Vol. 6, No. 2, 3, June/Sept. pp. 95-114.AfricaCraton, Tectonics
DS201012-0011
2010
Allen, P.A.Armitage, J.J., Allen, P.A.Cratonic basins and the long term subsidence history of continental interiors.Journal of the Geological Society, Vol. 167, 1, pp. 61-70.MantleConvection
DS201112-0014
2011
Allen, P.A.Allen, P.A.Surface impact of mantle processes.Nature Geoscience, Vol. 4, August pp. 498-499.MantleMantle plume
DS1960-0775
1967
Allen, P.M.Allen, P.M.The Geology of Part of the Orogenic Belt in Sierra LeoneLeeds: Ph.d. Thesis, University Leeds, Also: Geol. Rundsch., Vol. 58, PP. 588-620. IN 1969.Sierra Leone, West AfricaGeology, Tectonics, Rokell Formation, Regional Studies
DS1960-0776
1967
Allen, P.M.Allen, P.M., Snelling, N.J., Rex, D.C.Age Determinations from Sierra LeoneM.i.t. Annual Report 15th., NOS. 1381-1415.Sierra Leone, West AfricaGeochronology, Kimberlite
DS1960-0903
1968
Allen, P.M.Allen, P.M.The Stratigraphy of a Geosynclinal Succession in Western Sierra Leone.Geology Magazine (London), Vol. 105, PP. 61-73.Sierra Leone, West AfricaGeology
DS1980-0006
1980
Allen, P.M.Allen, P.M.Discussion of the Paper by Culver and Williams Entitled Late Precambrian and Phanerozoic Geology of Sierra Leone.Geological Society of London Journal, Vol. 137, PP. 511-512.Sierra Leone, West AfricaGeology, Related Rocks
DS1997-0020
1997
Allen, P.M.Allen, P.M.Standardization of mapping practices in the British geological SurveyComputers and Geosciences, Vol. 23, No. 6, pp. 609-612GlobalMapping, Computers - Program
DS1993-1013
1993
Allen, R.McPhie, J., Doyle, M., Allen, R.Volcanic texturesCodes Key Centre, University Of Of Tasmania, $ 90.00United States, Japan, New Zealand, Central and South AmericaBook -ad, Volcanic textures
DS1990-0113
1990
Allen, R.B.Allen, R.B.Bibliography of South American geology: Volume 1, ArgentinaEarth Sciences and Resources Institute, 373p. $ 75.00ArgentinaBibliography, Book -ad
DS1991-0015
1991
Allen, R.L.Allen, R.L.Nomenclature of volcaniclastics: discrimination of syn-eruptive and post-eruptive volcaniclasticsIavcei Newsletter, No. 5, October pp. 3-5GlobalVolcanics, Classification
DS1994-0039
1994
Allen, R.L.Allen, R.L.Nomenclature of volcaniclastics: description of syneruptive and posteruptive volcaniclastics.Preprint, 4p.Globalvolcanism., Classification
DS2002-0025
2002
Allen, R.M.Allen, R.M., Nolet, G., Morgan, W.J., Vogfjord, K., Bergsson, B.H., et al.Imaging the mantle beneath Iceland using integrated seismological techniquesJournal of Geophysical Research, Vol. 107, No. 11, Dec. 06, 10.1029/2001JB000595IcelandGeophysics - seismics
DS2003-1170
2003
Allen, R.M.Ritsema, J., Allen, R.M.The elusive mantle plumeEarth and Planetary Science Letters, Vol. 207, 1-4, Feb. 28, pp. 1-12.GlobalGeophysics - seismic tomography, Mantle upwelling
DS2003-1171
2003
Allen, R.M.Ritsema, J., Allen, R.M.The elusive mantle plumeEarth and Planetary Science Letters, Vol. 207, 1-4, pp. 1-12.MantleHot spots, plumes
DS200512-0012
2005
Allen, R.M.Allen, R.M., Xue, M.Constraining the geometry and flow of the Iceland mantle upwelling.www Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractEurope, IcelandMantle plume
DS200512-0838
2004
Allen, R.M.Penny, S.R., Allen, R.M., Harrison, S., Lees, T.C., Murphy, F.C., Norman, A.R., Roberts, P.A.A global scale exploration risk analysis technique to determine the best mineral belts for exploration.Transactions of Institute of Mining and Metallurgy, Vol. 113, September pp. 183-194.Economics - risk analysis
DS201012-0869
2010
Allen, R.M.Xue, M., Allen, R.M.Mantle structure beneath the western United States and its implications for convection processes.Journal of Geophysical Research, Vol. 115, B07303.United StatesTectonics
DS201112-0750
2011
Allen, R.M.Obrebski, M., Allen, R.M., Pollitz, F., Hung, S-H.Lithosphere asthenosphere interaction beneath the western United States from the joint inversion of body-wave traveltimes and surface wave phase veolocities.Geophysical Journal International, March 25, In press availableUnited StatesGeophysics - seismics
DS2001-0020
2001
Allen, T.Allen, T., Cooper, S.A., Cull, J.P.High definition gravity surveys and density modelling for kimberlite explorationExploration Geophysics (AusGeo (Geoscience Australia)), Vol. 32, No. 2, pp. 89-94.AustraliaGeophysics - gravity
DS2001-0021
2001
Allen, T.Allen, T., Cooper, S.A., Cull, J.P.High definition gravity surveys and density modelling for kimberlite exploration.Exploration Geophysics (Assocation of Exploration Geologists (AEG)), Vol. 32, No. 2, June, pp.89-94.Australia, SouthGeophysics - gravity, Nackara Arc, Hiles Lagoon
DS1986-0014
1986
Allen, V.Allen, V.Early Kimberley- a photographic souvenirKimberley, distributed by F.R. Thorold Africana Booksellers, 155p. approx. $ 15.00R.South AfricaHistory
DS1994-1378
1994
Allen and HoltPincock, Allen and HoltFeasibility studies -minimum reporting requirementsPincock, Allen and Holt Information Bulletin, 94-1, 4pUnited StatesEconomics, Reporting studies
DS1994-0327
1994
Allers, L.Collins, A.T., Allers, L., Wort, C.J.H.The annealing of radiation damage in De Beers colorless CVD diamondsDiamond Relations, # NN160, Vol. 3, No. 4-6. April pp. 932-935.GlobalCVD., Diamond radiation
DS2003-1085
2003
Allerton, S.Platt, J.P., Allerton, S., Kirker, A., Mandeville, C., Mayfield, D.The ultimate arc: differential displacement, oroclinal bending..Tectonics, Vol. 22,3,May, 10.1029/2001TC001321GlobalTectonics - arc
DS200412-1556
2003
Allerton, S.Platt, J.P., Allerton, S., Kirker, A., Mandeville, C., Mayfield, D.The ultimate arc: differential displacement, oroclinal bending...Tectonics, Vol. 22,3,May, 10.1029/2001 TC001321TechnologyTectonics - arc
DS1999-0009
1999
Alley, R.B.Alley, R.B., Clark, P.U.The deglaciation of the Northern Hemisphere: a global perspectiveAnnual Rev. Earth. Plan. Sci., Vol. 27, pp. 149-82.Canada, Russia, Europe, AsiaGeomorphology, Glacial - deglaciation
DS201709-1967
2017
Alley, R.B.Burkhart, P.A., Alley, R.B., Thompson, L.G., Balog, J.D., Baukdauf, P.E., Baker, G.S.Savor the cryosphere.GSA Today, Vol. 27, pp. 4-11.Globalglaciers

Abstract: This article provides concise documentation of the ongoing retreat of glaciers, along with the implications that the ice loss presents, as well as suggestions for geoscience educators to better convey this story to both students and citizens. We present the retreat of glaciers—the loss of ice—as emblematic of the recent, rapid contraction of the cryosphere. Satellites are useful for assessing the loss of ice across regions with the passage of time. Ground-based glaciology, particularly through the study of ice cores, can record the history of environmental conditions present during the existence of a glacier. Repeat photography vividly displays the rapid retreat of glaciers that is characteristic across the planet. This loss of ice has implications to rising sea level, greater susceptibility to dryness in places where people rely upon rivers delivering melt water resources, and to the destruction of natural environmental archives that were held within the ice. Warming of the atmosphere due to rising concentrations of greenhouse gases released by the combustion of fossil fuels is causing this retreat. We highlight multimedia productions that are useful for teaching this story effectively. As geoscience educators, we attempt to present the best scholarship as accurately and eloquently as we can, to address the core challenge of conveying the magnitude of anthropogenic impacts, while also encouraging optimistic determination on the part of students, coupled to an increasingly informed citizenry. We assert that understanding human perturbation of nature, then choosing to engage in thoughtful science-based decision-making, is a wise choice. This topic comprised “Savor the Cryosphere,” a Pardee Keynote Symposium at the 2015 Annual Meeting in Baltimore, Maryland, USA, for which the GSA recorded supporting interviews and a webinar.
DS1989-0986
1989
Alley, R.E.McGuffie, B.A., Johnson, L.F., Alley, R.E., Lang, H.R.IGIS Computer aided photogeologic mapping with image processing, graphic sand CAD/CAM capabilitiesGeobyte, Vol. 4, No. 5, pp. 8, 10-14. Database #18194GlobalComputer, Program -IGIS
DS1983-0008
1983
Allfred, C.W.Allfred, C.W.A South African Springtime Klip TrekLapidary Journal, Vol. 37, No. 1, APRIL, PP. 56-73.South AfricaTravelogue, Popular Guide
DS200412-1571
2004
Allialy, M.Poucler, A., Allialy, M., Daouda-Yao, B., Esso, B.Discovery of a diamond bearing kimberlite diatreme at Seguela in Ivory Coast.Comptes Rendus Geoscience, Vol. 336, 1, Jan. pp. 9-17.Africa, Ivory CoastLamproite, dikes
DS201412-0707
2004
Allialy, M.Pouclet, A., Allialy, M., Daouda-Yao, Esso, B.Decouverte d'un diatreme de kimberlite diamantifere a Seguela en Cote-d'Ivoire.Comptes Rendus Geoscience, Vol. 336, pp. 9-17.Africa, Ivory CoastDiatreme
DS200812-0022
2008
Allialy, M.E.Allialy, M.E., Djro, S.C., Yavouba, C., Konamelan, A.N., Pothin, K.B., Yao, D.B., Yobou, R.Comparative geochemistry of Seguela kimberlites, South Africa Group II kimberlites and other worldwide kimberlites.9IKC.com, 3p. extended abstractAfrica, West Africa, Ivory CoastDeposit - Bobi, Toubabouko
DS2002-0026
2002
Allibone, A.H.Allibone, A.H., McGuaig, T.C., Harris, D., EtheridgeStructural controls on gold mineralization at the Ashanti deposit, Obuasi GhanaSociety of Economic Geologists Special Publication, No.9,pp.65-93.GhanaGold, fault zones, Birimian, Deposit - Ashanti
DS1992-1372
1992
Allik, T.H.Shannon, R.D., IIshi, K., Allik, T.H., et al.Dielectric constants of BaO and melilites and the oxide additive ruleEuropean Journal of Mineralogy, Vol. 4, pp. 1241-1249.GlobalMelilites, Mineralogy
DS1975-0220
1976
Allingham, J.W.Allingham, J.W.Interpretation of Aeromagnetic Anomalies in Southeastern Missouri.United States Geological Survey (USGS) OPEN FILE., No. 76-868, 319P. 1: 250, 000GlobalGeophysics, Mid-continent
DS1996-0019
1996
Allison, M.Allison, M., et al.The significance of small scale mining for developing economiesCrs Perspectives, No. 52, Jan. pp. 8-9AfricaEconomics, Mining -small scale
DS1996-0020
1996
Allmendiger, R.W.Allmendiger, R.W., Gubbels, T.Pure and simple shear plateau uplift, Altiplano -Puna, Argentin a andBoliviaTectonophysics, Vol. 259, No. 1-3, June 30, pp. 1-14Argentina, BoliviaTectonics
DS1986-0598
1986
Allmendinger, R.Nelson, K.D., Allmendinger, R., Potter, C., Hauser, E., Brown, L.Reflection character of the continental MOHO and its tectonicsignificanceGeological Society of America (GSA) Abstract Volume, Vol. 18, No. 6, p. 704. (abstract.)GlobalTectonics
DS1983-0009
1983
Allmendinger, R.W.Allmendinger, R.W., Sharp, J.W., Von tish, D., Serpa, L.Cenozoic and Mesozoic Structure of the Eastern Basin and Range Province, Utah from Cocorp Seismic Reflection Data.Geology, Vol. 11, No. 9, PP. 532-536.GlobalMid-continent
DS1991-1060
1991
Allmendinger, R.W.Marrett, R., Allmendinger, R.W.Estimates of strain due to brittle faulting: sampling of faultpopulationsJournal of Structural Geology, Vol. 13, No. 6, pp. 735-738GlobalStructure, Sampling -faults
DS1993-1087
1993
Allmendinger, R.W.Mpodozis, C., Allmendinger, R.W.Extensional tectonics, Cretaceous Andes, northern ChileGeological Society of America Bulletin, Vol. 105, No. 11, November pp. 1462-1477ChileTectonics
DS1997-0021
1997
Allmendinger, R.W.Allmendinger, R.W., Jordan, T.E., Kay, S.M., Isacks, B.L.The evolution of the Altiplano-Puna Plateau of the Central AndesAnnual Review of Earth and Planetary Sciences, Vol. 25, pp. 139-174Andes, Bolivia, BrazilReview - plateau, Tectonics, stratigraphy
DS1960-0777
1967
Allsop, H.L.Allsop, H.L., Burger, A.J., Van zyl, C.A Minimum Age for the Premier Kimberlite Pipe Yielded by Biotite Rubidium-strontium (rb-sr) Measurements, with Related Galena Isotopic Data.Earth and Planetary Science Letters, Vol. 3, No. 2, PP. 161-166.South AfricaGeochronology, Isotope
DS1970-0477
1972
Allsop, H.L.Berg, G.W., Allsop, H.L.Low Sr 87 Sr 86 Ratios in Fresh South African KimberlitesEarth and Planetary Science Letters, Vol. 16, PP. 27-30.South AfricaGeochronology, Strontium
DS1970-0478
1972
Allsop, H.L.Berg, G.W., Allsop, H.L.Low 87 Sr / 86 Sr Ratios in South African KimberlitesEarth and Planetary Science Letters, Vol. 16, No. 1, PP. 27-30.South AfricaIsotope
DS1970-0629
1973
Allsop, H.L.Barrett, D.R., Allsop, H.L.Rubidium Strontium Age Determinations on South Africa Kimberlite Pipes.1st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 23-26.South AfricaGeochronology, Isotope
DS1975-0004
1975
Allsop, H.L.Allsop, H.L., Barrett, D.R.Rubidium-strontium Age Determinations on South African Kimberlite PipesPhysics and Chemistry of the Earth., Vol. 9, PP. 605-617.South Africa, Southwest Africa, NamibiaWesselton, Dutoitspan, De Beers, Bultfontein, Monastery, Roberts
DS1975-0024
1975
Allsop, H.L.Barrett, D.R., Allsop, H.L.Rubidium Strontium Age Determinations on South African Kimberlite Pipes.Physics and Chemistry of the Earth., Vol. 9, PP. 605-618.South AfricaIsotope, Geochronology
DS1981-0005
1981
Allsop, H.L.Allsop, H.L., Bristown, J.W., Manton, W.I., Cleverly, R.W.Rubidium-strontium Geochronology of the Lebombo VolcanicsGeocongress '81, South African Geodynamics Project., ABSTRACT VOLUME, PP. 1-2.GlobalDokolwayo, Lembo Volcanics
DS1982-0010
1982
Allsopp, C.M.Allsopp, C.M., Brumfield, K.E., Street, R.L.The Crustal Structure Associated with the East Continental Gravity High in Central Kentucky.Geological Society of America (GSA), Vol. 14, No. 5, P. 253, (abstract.).GlobalMid-continent, Geophysics
DS1987-0078
1987
Allsopp, H.Bristow, J., Allsopp, H., Skinner, E.M.W.Exciting signatures from the earth's mantleIndiaqua, No. 47, 1987/II, pp. 31-32, 34, 37, 38GlobalIsotope, Geochronology
DS1989-0276
1989
Allsopp, H.Colgan, E.A., Clark, T.C., Bristow, J.W., Allsopp, H.Geological setting, petrography and petrogenesis of olivine melilitites Of the Natal coast, South AfricaGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 419-435South AfricaMelilitite, Petrology
DS1980-0121
1980
Allsopp, H.I.Erlank, A.J., Allsopp, H.I., Duncan, A.R., Bristow, J.W.Mantle Heterogeneity Beneath Southern Africa: Evidence From a Volcanic Record.Royal Society of London PHIL. Transactions, Vol. 297, No. 1431, PP. 295-308.South AfricaTectonic
DS1982-0194
1982
Allsopp, H.L.Erlank, A.J., Allsopp, H.L., Hawkesworth, C.J., Menzies, M.A.Chemical and Isotopic Characterisation of Upper Mantle Metasomatism in Peridotite Nodules from the Bultfontein Kimberlite.Proceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, PP. 261-263, (abstract.).South AfricaKimberlite
DS1984-0009
1984
Allsopp, H.L.Allsopp, H.L., Roddick, J.C.Rubidium-Strontium and 40 Ar age determinations on phlogopite micas from the Pre-Lebombo group Dokolwayo kimberlite pipeGeological Society of South Africa Spec. Publishing Ed. Erlank, A.J., No. 13, pp. 267-272South AfricaGeochronology, Argon, Age Determinations
DS1985-0006
1985
Allsopp, H.L.Allsopp, H.L., Bristow, J.W., Skinner, E.M.W., Scott Smith.Rbsr Geochronology of Some Miocene West Australian LamproitesTransactions Geological Society of South Africa, Vol. 88, pt. 2, May-August pp. 341-345AustraliaLamproite, Geochronology
DS1985-0007
1985
Allsopp, H.L.Allsopp, H.L., Hargraves, R.B.Rbsr Ages and Paleomagnetic Dat a for Some Angolan Alkaline IntrusivesTransactions Geological Society of South Africa, Vol. 88, pt. 2, May-August pp. 295-299AngolaAlkaline Rocks
DS1986-0015
1986
Allsopp, H.L.Allsopp, H.L., Eriksson, S.C.The Phalaborwa complex: isotopic evidence for ancientlithosphericenrichmentGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 40. AbstractSouth AfricaCarbonatite, Rare earths
DS1986-0016
1986
Allsopp, H.L.Allsopp, H.L., Smith, C.B., Bristow, J.W., Brown, R., Kramers, J.D.A review of radiometric dating methods applicable to kimberlites And related rocksProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 109-111South AfricaGeochronology
DS1986-0110
1986
Allsopp, H.L.Bristow, J.W., Smithm, C.B., Allsopp, H.L., Shee, S.R., SkinnerSetting, geochronology and geochemical characteristics of 160 my kimberlites and related rocks from the Kuruman Province, SouthAfricaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 112-114South AfricaGeochronology
DS1986-0145
1986
Allsopp, H.L.Colgan, E.A., Allsopp, H.L.Geological setting, petrography and petrogenesis of olivineme lilitites on the Natal coast, South AfricaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 115-117South AfricaPetrography
DS1986-0751
1986
Allsopp, H.L.Smith, C.B., Allsopp, H.L., Kramers, J.D., Gurney, J.J., JagoutzIsotopic and geochemical studies of kimberlitic and included xenolithsProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 329-331South Africa, BotswanaBlank
DS1986-0752
1986
Allsopp, H.L.Smith, C.B., Allsopp, H.L., Kramers, J.D., Hutchinson, G., Roddick, J.C.Emplacement ages of Jurassic Cretaceous South African kimberlites by the RbSR method on phlogopite and whole rocksamplesTransactions Geological Society of South Africa, Vol. 88, pt. 2, May-August pp. 249-266South AfricaGeochronology
DS1989-0021
1989
Allsopp, H.L.Allsopp, H.L., Bristow, J.W., Smith, C.B., Brown, R., GleadowA summary of radiometric dating methods applicable To kimberlites and realted rocksGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 343-357Southern AfricaAge emplacement, Radiometric, Geochronolog
DS1989-0185
1989
Allsopp, H.L.Brown, R.W., Allsopp, H.L., Bristow, J.W., Smith, C.B.Improved precision of rubidium-strontium (Rb-Sr) dating of kimberliticmicas: an assessment ofa leaching techniqueChemical Geology, Vol. 79, pp. 125-136South AfricaMakganyene Kimberlite, Geochronology
DS1989-1379
1989
Allsopp, H.L.Shee, S.R., Bristow, J.W., Bell, D.R., Smith, C.B., Allsopp, H.L.The petrology of kimberlites, related rocks and associated mantle xenoliths from the Kuruman province, South Africa #2Geological Society of Australia Inc. Blackwell Scientific Publishing, No. 14, Vol. 1, pp. 60-82South AfricaMantle, Petrology
DS1989-1406
1989
Allsopp, H.L.Smith, C.B., Allsopp, H.L., Garvie, O.G., Kramers, J.D., JacksonNote on the uranium-lead (U-Pb) (U-Pb) perovskite method for dating kimberlites: examples fromChemical Geology, Vol. 79, pp. 137-145South Africa, Northwest TerritoriesGeochronology, Perovskite
DS1995-0025
1995
Allsopp, H.L.Allsopp, H.L., Smith, C.B., Seggie, A.G.The emplacement age and geochemical character of the Venetia kimberlitebodies, Limpopo Belt, n Transvaal.South African Journal of Geology, Vol. 98, No. 3, Sept. pp. 239-244.South AfricaGeochemistry, geochronology, Deposit -Venetia
DS1985-0008
1985
Allsopp, J.W.Allsopp, J.W., Bristow, J.W., Skinner, E.M.W.The Rubidium-Strontium geochronology of the Colossus kimberlite pipe,ZimbabweTransactions Geological Society of South Africa, Vol. 88, pt. 2, May-August pp. 245-248ZimbabweGeochronology, Kimberlites
DS2002-1637
2002
Allwardt, J.R.Van den Berg, A.P., Yuen, D.A., Allwardt, J.R.Non linear effects from variable thermal conductivity and mantle internal heating: implications for melting..Physics of the Earth and Planetary Interiors, Vol.129, 3-4, pp.359-75.MantleMelting - massive and secular cooling
DS1993-0025
1993
Almazy Rosii-Sakha Company Lt.Almazy Rosii-Sakha Company Lt.Transportable modular ore treatment plant for diamond concentration of geological samples.Handout Prospectors and Developers Association of Canada (PDAC)., 20p.RussiaMineral processing, Plant equipment -brief outline
DS1998-1457
1998
Almeida, A.Teixeira, N., Gaspar, J., Waissel, O., Almeida, A.Geology of the Juin a Diamondiferous province7th International Kimberlite Conference Abstract, pp. 905-7.BrazilMaars, Rio Negro Jurena Mobile Belt
DS1997-0022
1997
Almeida, C.N.Almeida, C.N., Beurlen, H., Sampalo, A.S.High pressure metamorphosed iron Ti ore hosting island arc tholeiites at Itatuba Paraiba as an indication -International Geology Review, Vol. 39, No. 7, July, pp. 589-608BrazilProterozoic suture Pajeu-Paraiba fold belt, Bororema Province
DS1991-0016
1991
Almeida, F.F.M.Almeida, F.F.M., Svisero, D.P.Structural setting and tectonic control of kimberlite and associated Rocks of BrasilProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 3-5BrazilTectonics, Structure
DS202103-0381
2021
Almeida, J.Giro, J.P., Almeida, J., Guedes, E., Bruno, H.Tectonic inheritances in rifts: the meaning of NNE lineaments in the continental rift of SE Brazil.Journal of South American Earth Sciences, Vol. 108, 103255. 17p. PdfSouth America, Brazillineaments, tectonics

Abstract: The effect of previous structures inheritance is known to be important in the development of tectonic rifts. A series of overlapping structures generally can be represented by lineaments marking the successive tectonic events. We studied the NNE structural lineaments corridor in the central region of the Ribeira Belt. We used a digital elevation model (DEM) and new and previous fieldwork data to investigate the structural control of such lineaments and their relevance for the Brazilian continental margin. Our results suggest that the NNE direction is a crustal weakness zone characterising corridors of intense ductile and brittle deformation which was recurrently reactivated. Aligned NNE Neoproterozoic-Ordovician ductile and brittle structures as foliations, shear zones, lithological boundaries, and fractures filled by pegmatitic veins coincide with the lineaments. During the Cretaceous rift, a transtensional sinistral regime generated NNE T-fractures filled by mafic dykes. In the Cenozoic, the NNE direction is represented by transfer and domino faults developed within a mega accommodation zone in an intracontinental rift system. Our results suggest that the NNE direction was active in this region throughout the Phanerozoic and has high relevance for the structural development of the continental margin of southeastern Brazil.
DS202111-1760
2021
Almeida, J.Bruno, H., Helibron, M., Strachen, R., Fowler, M., de MorrisonValeriano , C., Bersan, S., Moreira, H., Cutts, K., Dunlop, J., Almeida, R., Almeida, J., Storey, C.Earth's new tectonic regime at the dawn of the Paleozoic: Hf isotope evidence for efficient crustal growth and reworking in the Sao Francisco craton, Brazil.Geology, Vol. 49, 10, pp. 1214-1219. pdfSouth America, Brazilcraton

Abstract: A zircon Hf isotope data set from Archean and Paleoproterozoic magmatic and metasedimentary rocks of the southern São Francisco craton (Brazil) is interpreted as evidence of accretionary and collisional plate tectonics since at least the Archean-Proterozoic boundary. During the Phanerozoic, accretionary and collisional orogenies are considered the end members of different plate tectonic settings, both involving preexisting stable continental lithosphere and consumption of oceanic crust. However, mechanisms for the formation of continental crust during the Archean and Paleoproterozoic are still debated, with the addition of magmatic rocks to the crust being explained by different geodynamic models. Hf isotopes can be used to quantify the proportion of magmatic addition into the crust: positive ?Hf values are usually interpreted as indications of magmatic input from the mantle, whereas crust-derived rocks show more negative ?Hf. We show that the crust of the amalgamated Paleoproterozoic tectonostratigraphic terranes that make up the southern São Francisco craton were generated from different proportions of mantle and crustal isotopic reservoirs. Plate tectonic processes are implied by a consistent sequence of events involving (1) the generation of juvenile subduction-related magmatic arc rocks, followed by (2) collisional orogenesis and remelting of older crust, and (3) post-collisional bimodal magmatism.
DS1981-0405
1981
Almeida, J.S.Svisero, D.P., Felitti, W.F., Almeida, J.S.Geology of the Romaria Diamond Mine, Romaria, Minas GeraisMineracao Metalurgia., Vol. 44, No. 425, PP. 4-14.BrazilBlank
DS200812-0023
2008
Almeida, M.E.Almeida, M.E., Macambira, M.J.B., Valente, S.de C.New geological and single zircon Pb evaporation dat a from the central Guyana Domain, southeastern Roraima, Brazil: tectonic implications for the central shield.Journal of South American Earth Sciences, Vol. 26, 3, Nov. pp. 318-328.South America, Brazil, GuyanaTectonics, Roraima
DS202111-1760
2021
Almeida, R.Bruno, H., Helibron, M., Strachen, R., Fowler, M., de MorrisonValeriano , C., Bersan, S., Moreira, H., Cutts, K., Dunlop, J., Almeida, R., Almeida, J., Storey, C.Earth's new tectonic regime at the dawn of the Paleozoic: Hf isotope evidence for efficient crustal growth and reworking in the Sao Francisco craton, Brazil.Geology, Vol. 49, 10, pp. 1214-1219. pdfSouth America, Brazilcraton

Abstract: A zircon Hf isotope data set from Archean and Paleoproterozoic magmatic and metasedimentary rocks of the southern São Francisco craton (Brazil) is interpreted as evidence of accretionary and collisional plate tectonics since at least the Archean-Proterozoic boundary. During the Phanerozoic, accretionary and collisional orogenies are considered the end members of different plate tectonic settings, both involving preexisting stable continental lithosphere and consumption of oceanic crust. However, mechanisms for the formation of continental crust during the Archean and Paleoproterozoic are still debated, with the addition of magmatic rocks to the crust being explained by different geodynamic models. Hf isotopes can be used to quantify the proportion of magmatic addition into the crust: positive ?Hf values are usually interpreted as indications of magmatic input from the mantle, whereas crust-derived rocks show more negative ?Hf. We show that the crust of the amalgamated Paleoproterozoic tectonostratigraphic terranes that make up the southern São Francisco craton were generated from different proportions of mantle and crustal isotopic reservoirs. Plate tectonic processes are implied by a consistent sequence of events involving (1) the generation of juvenile subduction-related magmatic arc rocks, followed by (2) collisional orogenesis and remelting of older crust, and (3) post-collisional bimodal magmatism.
DS201703-0396
2017
Almeida, V.V.Almeida, V.V., Janasi, V.A., Heaman, L.M., Shaulis, B.J., Hollanda, M.H.B.M., Renne, P.R.Contemporaneous alkaline and tholeiitic magmatism in the Ponta Grossa Arch, Parana Etendeka magmatic province: constraints from U-Pb zircon baddeleyite and 40Ar/39Ar phlogopite dating of the Jose Fernandes gabbro and mafic dykes.Journal of Volcanology and Geothermal Research, in press available 11p.South America, BrazilAlkaline rocks

Abstract: We report the first high-precision ID-TIMS U-Pb baddeleyite/zircon and 40Ar/39Ar step-heating phlogopite age data for diabase and lamprophyre dykes and a mafic intrusion (José Fernandes Gabbro) located within the Ponta Grossa Arch, Brazil, in order to constrain the temporal evolution between Early Cretaceous tholeiitic and alkaline magmatism of the Paraná-Etendeka Magmatic Province. U-Pb dates from chemically abraded zircon data yielded the best estimate for the emplacement ages of a high Ti-P-Sr basaltic dyke (133.9 ± 0.2 Ma), a dyke with basaltic andesite composition (133.4 ± 0.2 Ma) and the José Fernandes Gabbro (134.5 ± 0.1 Ma). A 40Ar/39Ar phlogopite step-heating age of 133.7 ± 0.1 Ma from a lamprophyre dyke is identical within error to the U-Pb age of the diabase dykes, indicating that tholeiitic and alkaline magmatism were coeval in the Ponta Grossa Arch. Although nearly all analysed fractions are concordant and show low analytical uncertainties (± 0.3-0.9 Ma for baddeleyite; 0.1-0.4 Ma for zircon; 2?), Pb loss is observed in all baddeleyite fractions and in some initial zircon fractions not submitted to the most extreme chemical abrasion treatment. The resulting age spread may reflect intense and continued magmatic activity in the Ponta Grossa Arch.
DS1992-0018
1992
Almeida-Filho, R.Almeida-Filho, R., Castelo Branco, R.M.G.Location of kimberlite pipes using Land sat thematic mapper images and aerial photographs: the Redondao diatreme, BrasilInternational Journal of Remote Sensing, Vol. 13, No. 8, pp. 1449-1457BrazilKimberlite pipes, Remote sensing
DS1997-0023
1997
Al-Mishwat, A.T.Al-Mishwat, A.T.STASSAGE: a Fortran program to decode stratigraphic ages from the International IGADAT database.Computers and Geosciences, Vol. 23, No. 3, pp. 305-315.GlobalPetrology, igneous rocks, Stratigraphic age, database
DS1988-0760
1988
Almond, R.A.Williams, P.R., Johnston, C.R., Almond, R.A., Simamora, W.H.Late Cretaceous to early Tertiary structural elements of West KalimantanTectonophysics, Vol. 148, No. 3/4, May 1, pp. 279-298GlobalBlank
DS201212-0013
2012
Almor, Y.Almor, Y.Who's afraid ofirradiated diamonds?Hayashalom Magazine, No. 207, pp. 157-TechnologyDiamond - irradiation
DS201707-1302
2017
Almqvist, B.S.G.Almqvist, B.S.G., Mainprice, D.Seismic properties and anisotropy of the continental crust: predictions based on mineral texture and rock microstructure.Reviews of Geophysics, in press available 43p.Mantlegeophysics - seismics

Abstract: Progress in seismic methodology and ambitious large-scale seismic projects are enabling high-resolution imaging of the continental crust. The ability to constrain interpretations of crustal seismic data is based on laboratory measurements on rock samples and calculations of seismic properties. Seismic velocity calculations and their directional dependence are based on the rock micro fabric, which consists of mineral aggregate properties including crystallographic preferred orientation (CPO), grain shape and distribution, grain boundary distribution, and misorientation within grains. Single mineral elastic constants and density are crucial for predicting seismic velocities, preferably at conditions that span the crust. However, high temperature and pressure properties are not as common as elastic constants at standard temperature and pressure (STP) at atmospheric conditions. Continental crust has a very diverse mineralogy, however a select number appear to dominate seismic properties because of their high volume fraction contribution. Calculations of micro fabric-based seismic properties and anisotropy are performed with averaging methods that in their simplest form takes into account the CPO and modal mineral composition. More complex methods can take into account other microstructural characteristics, including the grain shape and distribution of mineral grains, and cracks and pores. A challenge for the geophysics and rock physics communities is the separation of intrinsic factors affecting seismic anisotropy, due to properties of crystals within a rock and apparent sources due to extrinsic factors like cracks, fractures and alteration. This is of particular importance when trying to deduce the state of crustal composition and deformation from seismic parameters.
DS201805-0961
2018
Almqvist, S.A.Mattsson, H.B., Balashova, A., Almqvist, S.A., Bosshard-Stadlin, S.A., Weidendorfer, D.Magnetic mineralogy and rock properties of silicate and carbonatite rocks from Oldoinyo Lengai volcano (Tanzania).Journal of African Earth Sciences, Vol. 142, pp. 193-206.Africa, Tanzaniadeposit - Oldoinyo Lengai

Abstract: Oldoinyo Lengai, a stratovolcano in northern Tanzania, is most famous for being the only currently active carbonatite volcano on Earth. The bulk of the volcanic edifice is dominated by eruptive products produced by silica-undersaturated, peralkaline, silicate magmas (effusive, explosive and/or as cumulates at depth). The recent (2007-2008) explosive eruption produced the first ever recorded pyroclastic flows at this volcano and the accidental lithics incorporated into the pyroclastic flows represent a broad variety of different rock types, comprising both extrusive and intrusive varieties, in addition to various types of cumulates. This mix of different accidental lithics provides a unique insight into the inner workings of the world's only active carbonatite volcano. Here, we focus on the magnetic mineralogy and the rock magnetic properties of a wide selection of samples spanning the spectrum of Oldoinyo Lengai rock types compositionally, as well from a textural point of view. Here we show that the magnetic properties of most extrusive silicate rocks are dominated by magnetite-ulvöspinel solid solutions, and that pyrrhotite plays a larger role in the magnetic properties of the intrusive silicate rocks. The natrocarbonatitic lavas, for which the volcano is best known for, show distinctly different magnetic properties in comparison with the silicate rocks. This discrepancy may be explained by abundant alabandite crystals/blebs in the groundmass of the natrocarbonatitic lavas. A detailed combination of petrological/mineralogical studies with geophysical investigations is an absolute necessity in order to understand, and to better constrain, the overall architecture and inner workings of the subvolcanic plumbing system. The results presented here may also have implications for the quest in order to explain the genesis of the uniquely natrocarbonatitic magmas characteristic of Oldoinyo Lengai.
DS201704-0616
2017
Almqvist. B.S.G.Almqvist. B.S.G., Mainprice, D.Seismic properties and anisotropy of the continental crust: predictions based on mineral texture and rock microstructure.Reviews of Geophysics, in press availableMantleGeophysics - seismic

Abstract: Progress in seismic methodology and ambitious large-scale seismic projects are enabling high-resolution imaging of the continental crust. The ability to constrain interpretations of crustal seismic data is based on laboratory measurements on rock samples and calculations of seismic properties. Seismic velocity calculations and their directional dependence are based on the rock micro fabric, which consists of mineral aggregate properties including crystallographic preferred orientation (CPO), grain shape and distribution, grain boundary distribution, and misorientation within grains. Single mineral elastic constants and density are crucial for predicting seismic velocities, preferably at conditions that span the crust. However, high temperature and pressure properties are not as common as elastic constants at standard temperature and pressure (STP) at atmospheric conditions. Continental crust has a very diverse mineralogy, however a select number appear to dominate seismic properties because of their high volume fraction contribution. Calculations of micro fabric-based seismic properties and anisotropy are performed with averaging methods that in their simplest form takes into account the CPO and modal mineral composition. More complex methods can take into account other microstructural characteristics, including the grain shape and distribution of mineral grains, and cracks and pores. A challenge for the geophysics and rock physics communities is the separation of intrinsic factors affecting seismic anisotropy, due to properties of crystals within a rock and apparent sources due to extrinsic factors like cracks, fractures and alteration. This is of particular importance when trying to deduce the state of crustal composition and deformation from seismic parameters.
DS1991-0017
1991
Almukhamedov, A.I.Almukhamedov, A.I., Zolotukhin, V.V., Smirnova, Ye.V., KonusovaRare earth elements in trap rocks of ancient platformsDoklady Academy of Science USSR, Earth Science Section, Vol. 309, No. 1-6, July pp. 199-202RussiaRare earths, Mantle
DS1991-1943
1991
Almukhamedov, A.I.Zolotukhin, V.V., Almukhamedov, A.I.Fractionation and alkalinity in the evolution of the source magmas of platform basite ( by example of the northwestern Siberian platform)Soviet Geology and Geophysics, Vol. 31, No. 10, pp. 13-19RussiaBasite, Magma
DS1991-1944
1991
Almukhamedov, A.I.Zolotukhin, V.V., Almukhamedov, A.I.Problems of trap magmatism of platformsSoviet Geology and Geophysics, Vol. 32, No. 1, pp. 26-34RussiaMagmatism, Basalt
DS1993-0026
1993
Almukhamedov, A.I.Almukhamedov, A.I., Zolotukhin, V.V., et al.Geochemical model of basalt magma hybridization exemplified by the Tulai-Kiryaka intrusion (Taimyr)Russian Geology and Geophysics, Vol. 34, No. 4, pp. 42-50RussiaGeochemistry -basalt magma, Deposit -Taimyr
DS1993-0981
1993
Almukhamedov, A.I.Matveyenkov, V.V., Almukhamedov, A.I., Dashevskaya, D.M.Amphibole pyroxenite xenoliths from the Gorringe Bank (northeasternAtlantic).Doklady Academy of Sciences USSR, Earth Science Section, Vol. 316, No. 3, pp. 99-101.GlobalXenoliths
DS1989-1689
1989
Almukhamedov, E.A.Zubkov, V.S., Smirnov, V.N., Pliusnin, G.S., Almukhamedov, E.A.1st Potassium-Argon dat a and Strontium isotopic composition of theDoklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 307, No. 6, pp. 1466-1470RussiaBasanite, Geochronology
DS1994-0040
1994
Al-Nashil JamalAl-Nashil JamalDog rib Nation participation in the Northwest Territories developmentProgramThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Section Meeting Oct. 12, Vancouver, List of speakersNorthwest TerritoriesUpdate
DS201707-1359
2017
Alonso, R.Presser, J.L.B., Vladykin, N.V., Bitschene, P.R., Tondo, M.J., Acevedo, R.D., Alonso, R., Benitez, P.Olivine-lamproite from Ybtyruzu lamproite field, eastern Paraguay. *** In SpaPyroclastic Flow *** Spa, Vol. 7, 1, pp. 1-15.South America, Paraguaylamproite

Abstract: Numerous Mesozoic bodies of lamproite-like intrusions are located NE and E of the city of Villarrica, Guairá Department, in eastern Paraguay. This magmatic field, known as Ybytyruzú Field, lies immediately on the margin of the SW part of Paranapanemá cratonic-block, just of the Asunción rift backs-horst and so related to deep crustal/lithospheric fracture zones.Mostly of observed rocks are weathered, however fresh samples were collected in dykes from Acaty (=Yzu-2), Tacuarita (=Yzu-7); lava/breccias from Mbocayaty (=Yzu-3); and sill from Salto Boni (=Yzu-6). They intrude, both, the sediments (Independencia Group and Misiones Formation) and the tholeiitic basalts of the Paraná Basin. In the present study we have performed petrographic and mineral chemistry data to show that all of the study rocks, from the Ybytyruzú Field, are lamproites (leucite lamproite from Yzu-2/Yzu-3/Yzu-7 and sanidine lamproite from Yzu-6).With respect to Yzu-2, Yzu-3 and Yzu-6, the following analyzes show the lamproite character: -phenocrysts/microphenocrysts of: olivine (mg# (Mg/(Mg+Fe)) 0.80-0.85), Al-poor diopside (Al2O3 0.53-2.09% and TiO2 0.65-1.61%), phlogopite/Al-poor-Ti phlogopite (mg# 0.76-0.85, TiO2 5.8-10.2% and Al2O3 12.7-13.9%), Mg-Ti magnetites and leucite (pseudomorphs). -and matrix phases of: Al-poor diopside (Al2O3 0.39-2.46% and TiO2 0.43-1.55%), Al-poor-Ti phlogopite/biotite (mg# 0.57-0.80, TiO2 5.6-10.2% and Al2O3 8.9-12.8%), Mg-Ti magnetites/Ti-magnetites; sanidine (0-4.0% Fe2O3, 0-2.6% BaO and 0-2.5% Na2O). And as accessory phases, ilmenite (0.2-5.7% MgO and 0.3-6.6% MnO), K and Ti-rich Feeckermanite/richterite (1.32-3.6% K2O and 4.7-9.0% TiO2), K-rich Fe-Mg-Mn amphiboles, apatite and quartz (Yzu-6). And so, Ybytyruzú lamproite-like intrusions authenticates the true lamproitic province in Paraguay. III; INTERNATIONAL, 2000 BRAZIL 2000; 3 1ST INTERNATIONAL GEOLOGICAL CONGRESS; ABSTRACTS VOLUME
DS201908-1804
2019
Alonso, R.Presser, J.B.L., Alonso, R., Rocca, M.Malvinas Islands ( Falkland Islands): advances in the inferred buried marine impact mega-structure.Researchgate, July 27p. PdfFalkland Islandsimpact structure

Abstract: In 1992 Rampino noticed a large, almost circular negative gravity anomaly (~30 mGal) on the Falkland Plateau to the WNW of Malvinas Islands/Falklnad Islands using satellite data then available, and speculated that it might be associated with a large (~250 km wide?) buried impact structure. In some more recent compilations Rocca & Presser (2015) and Rocca et al. (2017) was attended the Malvinas Islands/Falklnad Islands “buried impact structure” with particular care; but also these works was harshly criticized. The present text, which is an advance to demonstrate the certain possibilities that this Malvinas Islands/Falklnad Islands It could really be a very probable mega impact structure, gathers shows and evaluates the existing and available indirect information; like gravimetry (Isostasy, Free-air and Bouguer); seismic reflection (Geco Prakla); and, even commenting aspects of its magnetic behavior and its local geology. In all gravimetric analyses from the Malvinas Islands/Falklnad Islands “buried impact structure” it can be shown that an annulus of positive gravity anomaly surrounding a circular oval depression of negative (isostasy and Free-air)/much lower (Bouguer) values gravity anomaly. The most relevant gravimetric information would be the near circular to oval Bouguer gravity low anomaly (with a minimum value of ~150 mGal) surrounded by at least circular ~255 kilometers wide circular ring of positive gravity anomaly (maximum ~225 mGal); a very high values of Bouguer anomaly that are highly compatible with what is expected to be found in mega impact structures. The Malvinas probable impact structure shows almost 100 mGal superior to the volcanic complex of Iceland; so it seems obvious that Malvinas probable impact structure moves away from a speculation by mega-paleo-volcano origin. When gravimetrically modeled, a probable peak ring of ~255 km is evidenced; as well as, the inferred the ~550 km probable rim-crest; configuration that reproduces an almost perfect and symmetrical modeling of a very probable giant impact structure with its clear visible the very probable elements: rim crest-annulus basin-peak ring-central basin-peak ring-annulus basin-rim crest. Four Geco Prakla seismic reflection lines on the area located to the SW of the potential peak ring show a vertical and disturbed crystalline basement (the “peak ring”); in three of them, the “central basin” what would it be filled with sediments after impact (probable ejecta). Using the empirical formula of Assumpção et al. (2013) calculation for crustal thickness could be found very clearly strong CT distortion along Malvinas very probable giant impact structure: around 3400-4000 meters; as is to be expected in terrestrial mega impact structure. Harness the EMAG2v3 a global Earth Magnetic Anomaly Grid compiled from satellite (Meyer et al., 2017) for the Malvinas very probable giant impact structure a well superior anomaly was found and better definition than observed, using the same information, to the one characterized by the impact crater Chicxulub. The geological map of the Falkland Islands Government that was placed on top of the modeling isostasy gravimetric map where the approximate circumference of the very probable peak-ring and the very probable rim-crest is highlighted. This information allows to see that the largest island (West Malvinas) would be part of the very probable peak-ring and the smaller island (East Malvinas) would be part of the very probable rim-crest; both separated by the depression that would correspond to the very probable annulus basin. Based on what was analyzed in the Malvinas Islands area, we concluded the Malvinas exhibited geophysics traits of a large ancient asteroid impact; i.e. Malvinas very probable giant impact structure. Very probable impact structure what could be among one of the world's largest impact crater.
DS201911-2554
2019
Alonso, R.Presser, J.L.B., Alonso, R., Rocca, M.Malvinas Islands ( Falkland Islands): advances in the inferred buried marine impact mega-structure.Pyroclastic Flow Journal of Geology, Vol. 9, no. 1, pp. 1-14. pdf.Antarcticaimpact structure

Abstract: In 1992 Rampino noticed a large, almost circular negative gravity anomaly (~30 mGal) on the Falkland Plateau to the WNW of Malvinas Islands/Falkland Islands using satellite data then available, and speculated that it might be associated with a large (~250 km wide?) buried impact structure. In some more recent compilations Rocca & Presser (2015) and Rocca et al. (2017) was attended the Malvinas Islands/Falkland Islands “buried impact structure” with particular care; but also these works was harshly criticized. The present text, which is an advance to demonstrate the certain possibilities that this Malvinas Islands/Falklnad Islands It could really be a very probable mega impact structure, gathers shows and evaluates the existing and available indirect information; like gravimetry (Isostasy, Free-air and Bouguer); seismic reflection (Geco Prakla); and, even commenting aspects of its magnetic behavior and its local geology. In all gravimetric analyses from the Malvinas Islands/Falklnad Islands “buried impact structure” it can be shown that an annulus of positive gravity anomaly surrounding a circular oval depression of negative (isostasy and Free-air)/much lower (Bouguer) values gravity anomaly. The most relevant gravimetric information would be the near circular to oval Bouguer gravity low anomaly (with a minimum value of ~150 mGal) surrounded by at least circular ~255 kilometers wide circular ring of positive gravity anomaly (maximum ~225 mGal); a very high values of Bouguer anomaly that are highly compatible with what is expected to be found in mega impact structures. The Malvinas probable impact structure shows almost 100 mGal superior to the volcanic complex of Iceland; so it seems obvious that Malvinas probable impact structure moves away from a speculation by mega-paleo-volcano origin. When gravimetrically modeled, a probable peak ring of ~255 km is evidenced; as well as, the inferred the ~550 km probable rim-crest; configuration that reproduces an almost perfect and symmetrical modeling of a very probable giant impact structure with its clear visible the very probable elements: rim crest-annulus basin-peak ring-central basin-peak ring-annulus basin-rim crest. Four Geco Prakla seismic reflection lines on the area located to the SW of the potential peak ring show a vertical and disturbed crystalline basement (the “peak ring”); in three of them, the “central basin” what would it be filled with sediments after impact (probable ejecta). Using the empirical formula of Assumpção et al. (2013) calculation for crustal thickness could be found very clearly strong CT distortion along Malvinas very probable giant impact structure: around 3400-4000 meters; as is to be expected in terrestrial mega impact structure. Harness the EMAG2v3 a global Earth Magnetic Anomaly Grid compiled from satellite (Meyer et al., 2017) for the Malvinas very probable giant impact structure a well superior anomaly was found and better definition than observed, using the same information, to the one characterized by the impact crater Chicxulub. The geological map of the Falkland Islands Government that was placed ontop of the modeling isostasy gravimetric map where the approximate circumference of the very probable peak-ring and the very probable rim-crest is highlighted. This information allows to see that the largest island (West Malvinas) would be part of the very probable peak-ring and the smaller island (East Malvinas) would be part of the very probable rim-crest; both separated by the depression that would correspond to the very probable annulus basin. Based on what was analyzed in the Malvinas Islands area, we concluded the Malvinas exhibited geophysics traits of a large ancient asteroid impact; i.e. Malvinas very probable giant impact structure. Very probable impact structure what could be among one of the world's largest impact crater.
DS1995-1974
1995
Alonso, R.N.Vandervoot, D.S., Jordan, R.E., Zeitler. P.K., Alonso, R.N.Chronology of internal drainage and uplift southern Puna plateau, Argentine central AndesGeology, Vol. 23, No. 2, Feb. pp. 145-148Andes, ArgentinaGeochronology, Tectonics
DS201702-0234
2016
Alonso, R.N.Presser, J.L.B., Farina-Dolsa, S., Larroza-Cristaldo, F.A., Rocca, M., Alonso, R.N., Acededo, R.D., Cabral-Antunez, N.D., Baller, L., Zarza-Lima, P.R., Sekatcheff, J.M.Modeled mega impact structures in Paraguay: II the eastern region. **PortBoletin del Museo Nacional de Historia Narural del Paraguay, Vol. 20, 2, pp. 205-213. pdf available in * PortSouth America, ParaguayImpact Crater

Abstract: We report here the discovery and study of several new modeled large impact craters in Eastern Paraguay, South America. They were studied by geophysical information (gravimetry, magnetism), field geology and also by microscopic petrography. Clear evidences of shock metamorphic effects were found (e.g., diaplectic glasses, PF, PDF in quartz and feldspar) at 4 of the modeled craters: 1) Negla: diameter:~80-81 km., 2) Yasuka Renda D:~96 km., 3) Tapyta, D: ~80 km. and 4) San Miguel, D: 130-136 km. 5) Curuguaty, D: ~110 km. was detected and studied only by geophysical information. Target-rocks range goes from the crystalline Archaic basement to Permian sediments. The modeled craters were in some cases cut by tholeiitic/alkaline rocks of Mesozoic age and partially covered by lavas of the basaltic Mesozoic flows (Negla, Yasuka Renda, Tapyta and Curuguaty). One of them was covered in part by sediments of Grupo Caacupé (age: Silurian/Devonian). Some of these modeled craters show gold, diamonds, uranium and REE mineral deposits associated. All new modeled large impact craters are partially to markedly eroded.
DS201710-2257
2017
Alonso, R.N.Presser, J.L.B., Tondo, M.J., Dolsa, S.F., Rocca, M.C.L., Alonso, R.N., Benetiz, P., Larroza, F.A., Duarte, B.J.R., Cabral-Antunez, N.D.Brief comments on the impact metamorphism in Cerro Leon quartzites, western Paraguay. English abstract ** in PORTPyroclastic Flow, Vol. 7, 1,pp. 16-24.South America, Paraguayimpact diamonds

Abstract: The petrographic study of two samples (quartzite and impactite) of Cerro León, a mountain range located in the middle of very probable impact basins (Cerro Leon-1, 2, 3 and 4-department of Alto Paraguay, Western-Paraguay) indicated evidences of impact metamorphism: PDFs (Not decorated and decorated) and diaplectic glass. Associated with diaplectic glass, impact diamonds or diamond/lonsdaleite crystals (micro and small macros) were observed with a range of morphologies including isolated and mostly agglutinated crystal varieties. Impact diamonds estimated to have formed by carbonate impact metamorphism present in the sedimentary target-rock of the Silurian/Devonian age. The identification of elements that reveal the impact metamorphism, in the analyzed samples of the Cerro León, evidences that the area of occurrence that would have been indicated as Very Probable Impact Basin, would be more of an Impact Basin.
DS201802-0259
2017
Alonso, R.N.Presser, J.L.B., Alonso, R.N., Farina Dolsa, S., Larroza, F.A., Rocca, M.C.L., Hornes, K., Baller, L.Impact metamorphism evidence of Negla and Yasuka Renda large impact crater. ***PORT only abstract in eng Boletin Museum History Natural Paraguay ***IN PORT, Vol. 21, no. 2, pp. 69-82. pdfSouth America, Paraguayimpact craters
DS201412-0166
2014
Alp, E.E.Dauphas, N., Roskosz, M., Alp, E.E., Neuville, D.R., Hu, M.Y., Sio, C.K., Tissot, F.L.H., Zhao, J., Tissandier, L., Medard, E., Cordier, C.Magma redox and structural controls on iron isotope variations in Earth's mantle and crust.Earth and Planetary Science Letters, Vol. 398, pp. 127-140.MantleRedox
DS202009-1624
2020
Alp, E.E.Dorfman, S.M., Potapkin, V., Lv, M., Greenberg, E., Kupenko, I., Chumakov, A.I., Bi, W., Alp, E.E., Liu, J., Magrez, A., Dutton, S.E., Cava, R.J., McCammon, C.A., Gillet, P.Effects of composition and pressure on electronic states of iron in bridgmanite.American Mineralogist, Vol. 105, pp. 1030-1039. pdfMantleredox

Abstract: Electronic states of iron in the lower mantle's dominant mineral, (Mg,Fe,Al)(Fe,Al,Si)O3 bridgmanite, control physical properties of the mantle including density, elasticity, and electrical and thermal conductivity. However, the determination of electronic states of iron has been controversial, in part due to different interpretations of Mössbauer spectroscopy results used to identify spin state, valence state, and site occupancy of iron. We applied energy-domain Mössbauer spectroscopy to a set of four bridgmanite samples spanning a wide range of compositions: 10-50% Fe/total cations, 0-25% Al/total cations, 12-100% Fe3+/total Fe. Measurements performed in the diamond-anvil cell at pressures up to 76 GPa below and above the high to low spin transition in Fe3+ provide a Mössbauer reference library for bridgmanite and demonstrate the effects of pressure and composition on electronic states of iron. Results indicate that although the spin transition in Fe3+ in the bridgmanite B-site occurs as predicted, it does not strongly affect the observed quadrupole splitting of 1.4 mm/s, and only decreases center shift for this site to 0 mm/s at ~70 GPa. Thus center shift can easily distinguish Fe3+ from Fe2+ at high pressure, which exhibits two distinct Mössbauer sites with center shift ~1 mm/s and quadrupole splitting 2.4-3.1 and 3.9 mm/s at ~70 GPa. Correct quantification of Fe3+/total Fe in bridgmanite is required to constrain the effects of composition and redox states in experimental measurements of seismic properties of bridgmanite. In Fe-rich, mixed-valence bridgmanite at deep-mantle-relevant pressures, up to ~20% of the Fe may be a Fe2.5+ charge transfer component, which should enhance electrical and thermal conductivity in Fe-rich heterogeneities at the base of Earth's mantle.
DS202104-0614
2021
Alp, E.E.Wang, W.,Liu, J., Yang, H., Dorfman, S.M., Lv, M., Li, J., Zhao, J., Hu, M.Y., bi, W., Alp, E.E., Xiao, Y., Wu, Z., Lin, J-F.Iron force constants of bridgmanite at high pressure: implications for iron isotope fractionation in the deep mantle.Geochimica et Cosmochimica Acta, Vol. 294, pp. 215-231. pdfMantlebridgmanite

Abstract: The isotopic compositions of iron in major mantle minerals may record chemical exchange between deep-Earth reservoirs as a result of early differentiation and ongoing plate tectonics processes. Bridgmanite (Bdg), the most abundant mineral in the Earth’s lower mantle, can incorporate not only Al but also Fe with different oxidation states and spin states, which in turn can influence the distribution of Fe isotopes between Bdg and ferropericlase (Fp) and between the lower mantle and the core. In this study, we combined first-principles calculations with high-pressure nuclear resonant inelastic X-ray scattering measurements to evaluate the effects of Fe site occupancy, valence, and spin states at lower-mantle conditions on the reduced Fe partition function ratio (?-factor) of Bdg. Our results show that the spin transition of octahedral-site (B-site) Fe3+ in Bdg under mid-lower-mantle conditions generates a +0.09‰ increase in its ?-factor, which is the most significant effect compared to Fe site occupancy and valence. Fe2+-bearing Bdg varieties have smaller ?-factors relative to Fe3+-bearing varieties, especially those containing B-site Fe3+. Our models suggest that Fe isotopic fractionation between Bdg and Fp is only significant in the lowermost mantle due to the occurrence of low-spin Fe2+ in Fp. Assuming early segregation of an iron core from a deep magma ocean, we find that neither core formation nor magma ocean crystallization would have resulted in resolvable Fe isotope fractionation. In contrast, Fe isotopic fractionation between low-spin Fe3+-bearing Bdg/Fe2+-bearing Fp and metallic iron at the core-mantle boundary may have enriched the lowermost mantle in heavy Fe isotopes by up to +0.20‰.
DS201212-0375
2012
Alp, I.Kose, C., Alp, I., Ikibas, C.Statistical methods for segregation and quantification of minerals in ore microscopy.Minerals Engineering, Vol. 30, April pp. 19-32.TechnologyMicrographic image analysis -not specific to diamonds
DS201906-1317
2019
Alp. E.E.Liu, J., Wang, W., Yang, H., Wu, Z., Hu, M.Y., Zhao, J., Bi, W., Alp. E.E., Dauphas, N., Liang, W., Chen, B., Lin, J-F.Carbon isotopic signatures of super-deep diamonds mediated by iron redox chemistry.Geochemical Perspectives Letters, Vol. 10, pp. 51-55.Mantleredox

Abstract: Among redox sensitive elements, carbon is particularly important because it may have been a driver rather than a passive recorder of Earth’s redox evolution. The extent to which the isotopic composition of carbon records the redox processes that shaped the Earth is still debated. In particular, the highly reduced deep mantle may be metal-saturated, however, it is still unclear how the presence of metallic phases in?uences the carbon isotopic compositions of super-deep diamonds. Here we report ab initio results for the vibrational properties of carbon in carbonates, diamond, and Fe3C under pressure and temperature conditions relevant to super-deep diamond formation. Previous work on this question neglected the effect of pressure on the equilibrium carbon isotopic fractionation between diamond and Fe3C but our calculations show that this assumption overestimates the fractionation by a factor of ~1.3. Our calculated probability density functions for the carbon isotopic compositions of super-deep diamonds derived from metallic melt can readily explain the very light carbon isotopic compo- sitions observed in some super-deep diamonds. Our results therefore support the view that metallic phases are present during the formation of super-deep diamonds in the mantle below ~250 km.
DS200912-0418
2008
Alpasian, M.Kurt, M.S., Alpasian, M., Gnclu, M.C., Temel, A.Geochemistry of late stage medium to high K calc alkaline and shoshoninitc dikes in the Ulukla Basin, central Anatolia, Turkey; petrogenesis and tectonicsGeochemistry International, Vol. 46, 11, pp. 1145-1163.Europe, TurkeyShoshonite
DS1994-0041
1994
Alper, J.Alper, J.Earth's near-death experience.... mother of all mass extinctions occurred250 million years ago... reasons?Earth, Vol. 3, No. 1, January pp. 42-51RussiaSiberian traps, Mass extinction -earth
DS1993-0027
1993
Alphanet Communications CorpAlphanet Communications CorpDiamonds with a difference.. Canadian versus the Central African Republic diamond playPromotional Brochure, Handout From Two Day Seminar Held Vancouver, B.c. May, Facets.. a newsletter for the diamond industry 4pCentral African RepublicPromotional brochure, Company information
DS201906-1271
2019
Alpizar Segua, Y.Barry, P.H., de Moor, J.M., Giovannelli, D., Schrenk, M., Hummer, D.R., Lopez, T., Pratt, C.A., Alpizar Segua, Y., Battaglia, A., Beaudry, A., Bini, G., Cascante, M., d'Errico, G., di Carlo, M., Fattorini, D., Fullerton, K., H+Gazel, E., Gonzalez, G., HalForearc carbon sink reduces long term volatile recycling into the mantle.Nature , 588, 7753, p. 487.Mantlecarbon

Abstract: Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth’s surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth’s deep mantle and shallow crustal reservoirs, as well as Earth’s oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth’s deep mantle than previously estimated.
DS1994-1852
1994
Alric, G.Vidal, M., Alric, G.The Paleoproterozoic Birimian of Haute Comoe in the West African craton, Ivory Coast: a transtensional back-arc basinPrecambrian Research, Vol. 65, No. 1-4, January pp. 207-230GlobalCraton, Birimian
DS1999-0212
1999
Alric, V.Feraud, G., Alric, V., Haller, M.40 Ar-39 Ar dating of the Jurassic volcanic province of Patagonia:migrating magmatism related to GondwanaEarth and Planetary Science Letters, Vol. 172, No. 1-2, Oct. 15, pp. 83-96.GlobalSubduction, Argon, Magmatism - geochronology
DS202110-1599
2021
AlrosaAlrosaAlrosa has completed the first phase of a study into kimberlites' ability to absorb CO2 from the atmosphereMining Magazine.com, Sept. 16, 1p.Russiacarbon
DS1990-0197
1990
Al-Saad, D.Best, J.A., Barazangi, M., Al-Saad, D., Sawaf, T., Gebran, A.Bouguer gravity trends and crustal structure of the Palmyride Mountain Belt and surrounding northern Arabian platform in SyriaGeology, Vol. 18, No. 12, December pp. 1235-1239SyriaGeophysics -gravity, Craton
DS1993-1410
1993
Al-Saad, D.Seber, D., Barazangi, M., Chamov, T.A., Al-Saad, D., Sawaf, T., Khaddour, M.Upper crustal velocity structure and basement morphology beneath theGeophysical Journal International, Vol. 113, pp. 752-766.SyriaGeophysics -seismics, Tectonics
DS200712-0773
2007
Al-SayighNasir, S., Al-Khirbashi, S., Al-Sayigh, Alharthy, Mubarek, Rollinson, Lazki, Belouova, Griffin, KaminskyThe first record of allochthonous kimberlite within the Batain Nappes, eastern Oman.Plates, Plumes, and Paradigms, 1p. abstract p. A706.Africa, OmanBatain melange
DS200812-0787
2008
Al-SayighNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiEvolved carbonatitic kimberlite from the Batain Nappes, eastern Oman continental margin.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS200812-0788
2008
Al-SayighNasir, S., Al-Khirbash, Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, Belousa, Kaminsky, Theye, Massone, Al-BuaidiLate Jurassic Early Cretaceous kimberlite, carbonatite and ultramafic lamprophyric sill and dyke swarms from the Bomethra area, northeastern Oman.9IKC.com, 3p. extended abstractAfrica, Arabia, OmanPetrography
DS201012-0528
2010
Al-SayighNasir, S., Al-Khirbash, S., Rollinson, Al-Harthy, Al-Sayigh, Al-Lazki, A., Theye, T.Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, in press available, 28p.Africa, OmanCarbonatite
DS201112-0724
2011
Al-SayighNasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, Al-Sayigh, Al-Lazki, Theye, Massonne, BelousovaPetrogenesis of early Cretaceous carbonatite and ultramafic lamprophyres in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp. 47-74.Asia, OmanCarbonatite
DS200712-0774
2006
Al-Sayigh, A.Nasir, S., Al-Sayigh, A., Alharthy, A., Al-Lazki, A.Geochemistry and petrology of Tertiary volcanic rocks and related ultramafic xenoliths from the central and eastern Oman Mountains.Lithos, Vol. 90, 3-4, Sept. pp. 249-270.Africa, Arabia, OmanBasanites, xenoliths
DS201112-0723
2011
Al-Sayigh, A.Nasir, S., Al-Khirbash, S., Rollinson, H., Al-Harthy, A., Al-Sayigh, A., Al-Lazki, A.Petrogenesis of early Cretaceous carbonatite and ultramafic lamprophryes in a diatreme in the Batain Nappes, eastern Oman continental margin.Contributions to Mineralogy and Petrology, Vol. 161, 1, pp.Africa, OmanCarbonatite
DS1995-1550
1995
Alsdorf, D.E.Ravat, D., Langel, R.A., Alsdorf, D.E.Global vector and scalar MAGSAT magnetic anomaly mapsJournal of Geophysical Research, Vol. 100, No. 10, Oct, 10, pp. 111-136.GlobalGeophysics -magnetics, Magsat
DS1990-0295
1990
Al-Shaieb, Z.Cemen, I., Al-Shaieb, Z.Tectonic habitat and structural styles in the mid-continent and southernOklahoma: implications for hydrocarbon accumulationGeological Society of America (GSA) South Central Section Annual Meeting, to be held March, Midcontinent, OklahomaTectonics, Ouachita Mountains
DS1995-1405
1995
Al-Shaieb, Z.Ortoleva, P., Al-Shaieb, Z., Puckette, J.Genesis and dynamics of basin compartments and sealsAmerican Journal of Science, Vol. 295, April pp. 345-427GlobalBasin, Overview -genesis, dynamics, feedback phenomena
DS1995-0026
1995
Alsina, D.Alsina, D., Woodward, R.L.Upper mantle shear velocity structure of North AmericaEos, Vol. 76, No. 46, Nov. 7. p.F422. Abstract.Mantle, North AmericaGeophysics -seismic
DS1997-0484
1997
Alsobrook, A.F.Harvey, C.C., Alsobrook, A.F.Industrial minerals in the 21st Century: a perspective of trends inmarkets, technologies and applicationsSociety for Mining, Metallurgy and Exploration (SME) Preprint, No. 97-124, 7pGlobalEconomics, Industrials
DS2000-0013
2000
Alsop, G.I.Alsop, G.I., Brown, J.P., Gibling, M.R.The geometry of drag zones adjacent to salt diapirsJournal of Geological Society of London, Vol. 157, No. 5, Sept.pp.1019-30.GlobalStructure - diapirs ( salt) not specific to diamond
DS1970-0461
1972
Alt, D.Alt, D., Hyndman, D.W., Ferguson, J.A., Lamorre, B.Pleistocene Maar Craters Near Drummond, MontanaNorthwest Geology, Vol. 1, PP. 33-37.United States, Montana, Rocky MountainsDiatreme
DS1987-0306
1987
Alt, D.Hyndman, D.W., Alt, D.Radial dikes, laccoliths and gelatin modelsJournal of Geology, Vol. 95, No. 6, November pp. 763-774MontanaShonkinite
DS1990-1327
1990
Alt, D.Sears, J.W., Alt, D.A composite Proterozoic cratonic basin drawn from examples in North America and AustraliaGeological Society of Australia, Abstracts No. 26, 9th. Inter. Conference on Basement, p. 25, AbstractsMidcontinent, AustraliaCraton, Tectonics
DS1998-0023
1998
Alt, J. C.Alt, J. C.Sulfur in serpentinized oceanic peridotites: serpentinization processes-microbial sulfate reductionJournal of Geophysical Research, Vol. 13, No. 5, May 10, pp. 9917-30GlobalPeridotites, Sulfidation
DS1995-0027
1995
Alt, J.C.Alt, J.C.Sulfur isotope profile through the oceanic crust: sulfur mobility and seawater crustal sulfur exchange.Geology, Vol. 23, No. 7, July pp. 585-588GlobalAlteration -hydrothermal
DS201709-1980
2011
Altanshagai, G.Dorjnamjaa, D., Voinkov, D.M., Kondratov, L.S., Selenge, D., Altanshagai, G., Enkhbatar, B.Concerning diamond and gold bearing astropipes of Mongolia.International Journal of Astronomy and Astrophysics, Vol. 1, pp. 98-104.Asia, Mongoliaastropipes, impact craters

Abstract: In this paper we present summation of eighteen year’s investigation of the all gold and diamond-bearing astropipes of Mongolia. Four astropipe structures are exemplified by the Agit Khangay (10 km in diameter, 470 38' N; 960 05' E), Khuree Mandal (D=11 km; 460 28' N; 980 25' E), Bayan Khuree (D=1 km; 440 06' N; 1090 36' E), and Tsenkher (D=7 km; 980 21' N; 430 36' E) astropipes of Mongolia. Detailed geological and gas-geochemical investigation of the astropipe structures show that diamond genesis is an expression of collision of the lithospheric mantle with the explosion process initiated in an impact collapse meteor crater. The term "astropipes" (Dorjnamjaa et al., 2010, 2011) is a neologism and new scientific discovery in Earth science and these structures are unique in certain aspects. The Mongolian astropipes are genuine "meteorite crater" structures but they also contain kimberlite diamonds and gold. Suevite-like rocks from the astropipes contain such minerals, as olivine, coesite, moissanite (0,6 mm), stishovite, coesite, kamacite,tektite, khamaravaevite (mineral of meteorite titanic carbon), graphite-2H, khondrite, picroilmenite, pyrope, phlogopite, khangaite (tektite glass, 1,0-3,0 mm in size), etc. Most panned samples and hand specimens contain fine diamonds with octahedrol habit (0, 2-2,19 mm, 6,4 mg or 0,034-0,1 carat) and gold (0,1-5 g/t). Of special interest is the large amount of the black magnetic balls (0,05-5,0 mm) are characterized by high content of Ti, Fe, Co, Ni, Cu, Mn, Mg, Cd, Ga, Cl, Al, Si, K. Meanwhile, shatter cones (size approx. 1.0 m) which are known from many meteorite craters on the Earth as being typical of impact craters were first described by us Khuree Mandal and Tsenkher astropipe structures. All the described meteorite craters posses reliable topographic, geological, mineralogical, geochemical, and aerospace mapping data, also some geophysical and petrological features (especially shock metamorphism) have been found, all of which indicate that these structures are a proven new type of gold-diamond-bearing impact structure, termed here "astropipes". The essence of the phenomenon is mantle manifestation and plume of a combined nuclear-magma-palingenesis interaction.
DS2000-0014
2000
Altenberger, U.Altenberger, U., Wilhelm, S.Ductile deformation of Potassium feldspar in dry eclogite facies shear zones in Bergen Arcs Norway.Tectonophysics, Vol. 320, No. 2, May 15, pp.107-21.NorwayTectonics, Eclogites
DS1991-0018
1991
Altermann, W.Altermann, W., Halbich, I.W.Structural history of the southwestern corner of the Kaapvaal Craton And the adjacent Namaqua realm: new observations and a reappraisalPrecambrian Research, Vol. 52, No. 1/2, pp. 133-166Southern AfricaKaapvaal Craton, Tectonics
DS1999-0504
1999
Altermann, W.Nelson, D.R., Tr\endall, A.F., Altermann, W.Chronological correlations between the Pilbara and Kaapvaal CratonsPrecambrian Research, Vol. 97, No. 3-4, Sept. pp. 165-90.Australia, South AfricaGeochronology, Craton - Pilbara, Kaapvaal
DS200512-0118
2005
Althaus, T.Buikin, A., Trieloff, M., Hopp,J., Althaus, T., Korochantseva, E., Schwarz, W.H., Altherr, R.Noble gas isotopes suggest deep mantle plume source of late Cenozoic mafic alkaline volcanism in Europe.Earth and Planetary Science Letters, Vol. 230, 1-2, pp. 143-162.EuropeAlkaline rocks, geochronology
DS1992-0103
1992
Altherr, R.Becker, H., Altherr, R.Evidence from ultra high pressure marbles for recycling of sediments into the mantleNature, Vol. 358, August 27, pp. 745-748AustriaMantle, Orogenic belts
DS1992-0702
1992
Altherr, R.Henjeskunst, F., Altherr, R.Metamorphic petrology of xenoliths from Kenya and northern Tanzania And implications for geotherms and lithospheric structuresJournal of Petrology, Vol. 33, No. 5, October pp. 1125-1156Tanzania, KenyaXenoliths, GeotherM.
DS1997-1296
1997
Altherr, R.Zeyen, H., Volker, F., Altherr, R.Styles of continental rifting: crust mantle detachment and mantle plumesTectonophysics, Vol. 278, No. 1-4, Sept. 15, pp. 329-AfricaTectonics, Rifting, mantle
DS2002-1735
2002
Altherr, R.Woodland, A.B., Seitz, H.M., Altherr, R., Marschall, H., Olker, B., Ludwig, T.Li abundances in eclogite minerals: a clue to a crustal or mantle origin?Contributions to Mineralogy and Petrology, Vol. 143, 5, pp.587-601.MantleEclogites - lithium
DS2002-1736
2002
Altherr, R.Woodland, A.B., Seitz, H.M., Altherr, R., Marschall, H., Olker, B., Ludwig, T.Li abundances in eclogite minerals: a clue to a crustal or mantle origin?Contributions to Mineralogy and Petrology, Vol.143,5, Aug.pp.587-601.MantleMineralogy - ecologite
DS2003-1492
2003
Altherr, R.Witt Eickschen, G., Seck, H.A., Mezger, K., Eggins, S.M., Altherr, R.Lithospheric mantle evolution beneath the Eifel ( Germany): constraints from Sr Nd PbJournal of Petrology, Vol. 44, 6, pp. 1077-96.GermanyMineral chemistry
DS200412-0021
2004
Altherr, R.Altherr, R., Meyer, H.P., Holl, A., Volker, F., Alibert, C., McCulloch, M.T., Majer, V.Geochemical and Sr Nd Pb isotopic characteristics of Late Cenozoic leucite lamproites from the East European Alpine belt ( MacedContributions to Mineralogy and Petrology, Vol. 147, 1, pp. 58-73.Europe, MacedoniaLamproite, geodynamics
DS200412-2138
2003
Altherr, R.Witt Eickschen, G., Seck, H.A., Mezger, K., Eggins, S.M., Altherr, R.Lithospheric mantle evolution beneath the Eifel ( Germany): constraints from Sr Nd Pb isotopes and trace element abundances in sJournal of Petrology, Vol. 44, 6, pp. 1077-96.Europe, GermanyGeochronology Mineral chemistry
DS200512-0118
2005
Altherr, R.Buikin, A., Trieloff, M., Hopp,J., Althaus, T., Korochantseva, E., Schwarz, W.H., Altherr, R.Noble gas isotopes suggest deep mantle plume source of late Cenozoic mafic alkaline volcanism in Europe.Earth and Planetary Science Letters, Vol. 230, 1-2, pp. 143-162.EuropeAlkaline rocks, geochronology
DS200612-0867
2006
Altherr, R.Mareschall, H.R., Altherr, R., Rupke, L.Squeezing out the slab - modelling the release of Li, Be and B during progressive high pressure metamorphism.Chemical Geology, in press available,MantleSubduction zone
DS200612-1518
2006
Altherr, R.Weinstein, Y., Navon, O., Altherr, R., Stein, M.The role of lithospheric mantle heterogeneity in the generation of Plio-Pleistocene alkali basaltic suites from NW Harrat Ash Sham (Israel).Journal of Petrology, Vol. 47, 5, pp. 1017-1050.Europe, IsraelBasalts - not specific to diamonds
DS200912-0276
2009
Altherr, R.Hannahan, M., Brey, G., Woodland, A., Altherr, R., Seitz, H-M.Li as a barometer for bimineralic eclogites: experiments in CMAS.Contributions to Mineralogy and Petrology, In press available 16p.MantleEclogite - barometry
DS200912-0348
2009
Altherr, R.Kaeser, B., Olker, B., Kait, A., Altherr, R., Pettke, T.Pyroxenite xenoliths from Marsabit ( northern Kenya): evidence for different magmatic events in the lithospheric mantle and interaction between peridotiteContributions to Mineralogy and Petrology, Vol. 157, 4, pp. 453-472.Africa, KenyaMagmatism
DS200912-0549
2009
Altherr, R.Olker, B., Kait, A., Altherr, R., Pettke, T.Evidence for different magmatic events in the lithospheric mantle and interaction between peridotite and pyroxenite. East African RiftPetrology, Vol. 157, 4, pp. 453-472.MantleGeothermometry
DS201112-0125
2010
Altherr, R.Buikin, A.I., Trieloff, M., Korochantseeva, E.V., Hopp, J., Kaliwood, M., Meyer, H-P.,Altherr, R.Distribution of mantle and atmospheric argon in mantle xenoliths from western Arabian Peninsula: constraints on timing and composition of metasomatizing agents....Journal of Petrology, Vol. 51, pp. 2547-2570.Africa, ArabiaMetasomatism
DS1995-0028
1995
Altmark Energy Inc.Altmark Energy Inc.Property option agreement with Kensington Resources... Fort a la Corneregion.Aaron Oil Corp. (Formerly), Oct. 27, 1p.SaskatchewanNews item, Kensington Resources
DS1990-0114
1990
Altobelli, C.Altobelli, C.How to value irradiated diamondsJewelers Circular Keystone, Vol. 161, No. 3, March p. 130GlobalDiamond morphology, Irradiated diamonds
DS2000-0738
2000
Altukhov, E.N.Osokin, E.D., Altukhov, E.N., Kravchenko, S.M.Criteria and formation and localization conditions of giant rare element deposits.Geol. Ore Dep., Vol. 42, No. 4, pp. 351-7.RussiaCarbonatite
DS1988-0007
1988
Altukhov, Ye.N.Altukhov, Ye.N., Pokhvisneva, Ye.A.Laws of carbonatite location.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 298, No. 3, pp. 684-687RussiaCarbonatite, Distribution
DS1989-0022
1989
Altukhov, Ye.N.Altukhov, Ye.N., Pokhvisneva, Ye.A.Patterns of distribution of carbonatitesDoklady Academy of Science USSR, Earth Science Section, Vol. 298, No. 1-6, April pp. 60-63RussiaCarbonatite, Distribution
DS201012-0721
2010
AltukhovaSmelov, A.P., Andreev, Altukhova, Babushkin, Bekrenev, Zaitsev.Izbekov, Koroleva, Mishmin, Okrugin, OleinkovKimberlites of the Manchary pipe: a new kimberlite field in central Yakutia.Russian Geology and Geophysics, Vol. 51, pp. 121-126.Russia, YakutiaDeposit - Manchary
DS1988-0008
1988
Altukhova, Z.A.Altukhova, Z.A., Talnikova, S.B.Typomorphic indications of hydrothermal haloes Of kimberlite pipes in carbonate country rocks.(Russian)Topomineral. I Tipomorfizm. Mineralov. Yakutsk.(Russian), pp. 36-43RussiaAlteration, metamorphism
DS1990-0115
1990
Altukhova, Z.A.Altukhova, Z.A., Talnikova, S.B.Rare earth elements in autolith-bearing kimberlite breccias as indicators of geochemical evolution of the kimberlite systemInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 780-781RussiaGeochemistry, Kimberlite -rare earths
DS1995-0029
1995
Altukhova, Z.A.Altukhova, Z.A., Barashkov, Yu.P.Reasons of variations of individual diamond crystals and petrogenetic blocking of rocks in Udachnaya pipe.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 5-7.Russia, Siberia, YakutiaPetrography, Deposit -Udachnaya
DS2003-1255
2003
Altukhova, Z.A.Shamshina, E.A., Altukhova, Z.A., Babushkina, S.A.Facial characteristics of kimberlite rocks from the northern and southern parts of the8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractRussia, YakutiaBlank
DS200412-1792
2003
Altukhova, Z.A.Shamshina, E.A., Altukhova, Z.A., Babushkina, S.A.Facial characteristics of kimberlite rocks from the northern and southern parts of the Yakutian kimberlite province ( in the lig8 IKC Program, Session 7, POSTER abstractRussia, YakutiaKimberlite petrogenesis
DS1975-0661
1978
Altukohov, YE. N.Altukohov, YE. N.Precambrian Rift Like Structures of SiberiaDoklady Academy of Science USSR, Earth Science Section., Vol. 241, No. 1-6, PP. 89-91.RussiaKimberlite
DS1988-0009
1988
Altukov, E.N.Altukov, E.N., Pokhvisneva, E.A.On the regularities of carbonatite distribution. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 298, No. 3, pp. 684-688RussiaCarbonatite
DS201712-2670
2017
Alty, R.Alty, R.Diavik diamond mines - 2016 Socio-economic Monitoring Agreement performance.45th. Annual Yellowknife Geoscience Forum, p. 2 abstractCanada, Northwest Territoriesdeposit - Diavik

Abstract: At Diavik, sustainable development is integrated into everything we do. Our operations provide benefits and opportunities for local communities, businesses, and governments. We work with all our stakeholders to deliver substantial and lasting benefits. The Diavik sustainable development report, is a requirement under the Diavik socio-economic monitoring agreement (SEMA). Through this report information on annual training, employment, business benefits, and community initiatives are available to the public. During this session of the Geoscience discussion, we will be sharing the Diavik Diamond mine performance under the SEMA up to and including December 2016.
DS1994-1898
1994
Alumente-Modreski, R.M.Wenrich, K.J., Alumente-Modreski, R.M.Geochemical soil sampling for deeply buried mineralized breccia pipes, northwestern ArizonaApplied Geochemistry, Vol. 9, pp. 431-454ArizonaGeochemistry, Uranium breccia pipes
DS2002-0730
2002
AlvaradoHoernle, K., Van den Bogaard, P., Werner, R., Lissinaa, B., Hauff, F., AlvaradoMissing history ( 16 -71 Ma) of the Galapagos hotspot: implications for the tectonicGeology, Vol. 30, 9, Sept. pp. 795-98.United StatesTectonics
DS1997-0024
1997
Alvarado, G.E.Alvarado, G.E., Denyer, P., Sinton, C.W.The 89 Tortugal komatiitic suite, Costa Rica: implications for a common geological origin .... mantleGeology, Vol. 25, No. 5, May pp. 439-442Costa Rica, CaribbeanKomatiites, Mantle plume
DS1999-0754
1999
Alvarenga, C.J.S.Uhlein, A., Trompette, R.R., Alvarenga, C.J.S.Neoproterozoic glacial and gravitational sedimentation on a continental rifted margin: Jequitaf-Macaubas ...Journal of African Earth Sciences, Vol. 12, No. 5, Sept. pp. 435-51.Brazil, Minas GeraisTectonics, Geomorphology
DS202108-1279
2021
Alvarez, O.Dragone, G.N., Bologna, M.S., Ussami, N., Gimenez, M.E., Alvarez, O., Klinger, F.G.L., Correa-Otto, S.Lithosphere of South American intracratonic basins: electromagnetic and potential field data reveal cratons, terranes, and sutures.Tectonophysics, Vol. 811, 13p. PdfSouth America, Argentinacratons

Abstract: A magnetotelluric survey comprising 18 broadband stations disposed along a 450 km-long profile was carried out at the transition between the Chaco-Paraná (CPB) and the Paraná (PB) intracratonic basins in northeastern Argentina. Three-dimensional inversions of the responses show that the CPB and southern PB lithospheres are resistive (~103 ? m) down to 120 km, but with distinct crustal and upper mantle electrical properties. Also, Bouguer gravity and density anomalies are positive at CPB, whereas they are negative at PB. We associate the CPB lithosphere with the Paleoproterozoic Rio Tebicuary craton and the southern PB lithosphere with an ancient and buried piece of craton, the Southern Paraná craton. Geochemical data of mantle xenoliths from the Cenozoic alkaline/carbonatitic province within the Rio Tebicuary craton suggest a subcontinental lithospheric mantle affected by metasomatic processes, which explains its lower resistivity (reaching values as low as 300 ? m) and higher density (#Mg = 0.87). In contrast, the Southern Paraná craton is more resistive (>103 ? m) and less dense, suggesting a de-hydrated, depleted, and thicker craton. These cratons are separated by a crustal conductor (15 to 20 km depth; 1-10 ? m) that we interpret as a southward continuation of a linear anomaly (Paraná Axial Anomaly) defined in former induction studies within the PB in Brazil. Hence, we redefined the trace of this conductive lineament: instead of bending towards the Torres Syncline, it continues inside the CPB. We propose the lineament to be an Early Neoproterozoic suture zone that controlled the location of maximum subsidence in the intracratonic basins during the Paleozoic. In the Early Cretaceous, the Paraná Axial Anomaly was the site of maximum extrusion and deposition of Serra Geral basalts. This anomaly separates compositionally distinct cratonic lithospheres along its path. Melting of this heterogeneous and enriched mantle created the Paraná igneous province.
DS1996-1126
1996
Alvarez, P.Poidevin, J.L., Alvarez, P.Un segment proximal de rampe carbonatee d'age proterozoique superieur au Nord du Craton d'Afrique..Journal of African Earth Sciences, Vol. 23, No. 2, August pp. 257-266Central African RepublicProterozoic, Craton, stratigraphy
DS2000-0015
2000
Alvarez, P.Alvarez, P.A quantified method for the study of non-fossiliferous clastic formations, pre-Pan African sandstone from Central Africa and the northern Democratic Republic Congo.Journal of African Earth Sciences, Vol. 31, 2, pp. 263-84.Central Africa, Democratic Republic of Congo, ZaireSedimentology, Diamonds in sediments
DS1997-1185
1997
Alvarez, V.C.Valdespino, O.E.M., Alvarez, V.C.Paleomagnetic and rock magnetic evidence for inverse zoning in the Parquazabatholith, tectonics of shieldPrecambrian Research, Vol. 85, No. 1-2, Nov. 1, pp. 1-26Venezuela, GuyanaTectonics, Paleomagnetism
DS200712-0115
2006
Alvarez Marron, J.Brown, D., Puchkov, V., Alvarez Marron, J., Bea, F., Perez Estaun, A.Tectonic processes in the southern and middle Urals: an overview.Geological Society of London Memoir, No. 32, pp. 407-420.Russia, Europe, UralsTectonics
DS1997-0134
1997
Alvarez-MarronBrown, D., Alvarez-Marron, Perez-Estaun, A., GorozhaninaGeometric and kinematic evolution of the foreland thrust and fold belt In the southern UralsTectonics, Vol. 16, No. 3, June, pp. 551-562GlobalTectonics
DS2000-0113
2000
Alvarez-MarronBrown, D., Carbonell, R., Alvarez-Marron, TryggvasonCrustal and upper mantle structure reveal arc continent collision processes in the southern Uralides.Igc 30th. Brasil, Aug. abstract only 1p.Europe, UralsCraton - East European, Magnitogorsk arc
DS2000-0016
2000
Alvarez-Marron, J.Alvarez-Marron, J., Brown, D., Gorozhanina, Y.Accretionary complex structure and kinematics during Paleozoic arc continent collision in the southern UralsTectonophysics, Vol. 235, No. 1-2, Oct. 15, pp. 175-Russia, UralsTectonics
DS2001-0135
2001
Alvarez-Marron, J.Brown, D., Alvarez-Marron, J., Perez-Estaun, PuchkovStructure and evolution of the Magnitogorsk forearc basin: identifying upper crustal processes during arcTectonics, Vol. 20, No. 3, June pp. 364-75.Russia, UralsTectonics, arc terranes, subduction zone
DS200712-0116
2006
Alvarez-Marron, J.Brown, D., Spadea, P., Puchkov, V., Alvarez-Marron, J., Herrington, R., Willner, A.P., Hetzel, R., Gorozhanina, Y., Juhlin, C.Arc continent collision in the southern Urals.Earth Science Reviews, in press availableRussia, UralsBaltica tectonics, UHP, geochemistry
DS201412-0006
2014
Alvarez-Valero, A.M.Alvarez-Valero, A.M., Jagoutz, O., Stanley, J., Manthei, C., Ali Moukadiri, A., Piasecki, A.Crustal attenuation as a tracer for the emplacement of the Beni Bousera ultramafic massif ( Betico-Rifean belt).Geological Society of America Bulletin, Vol. 126, no. 11/12, pp. 1614-1624.Africa, MoroccoBeniBoussera
DS201502-0038
2015
Alvaro, M.Angel, R.J., Alvaro, M., Nestola, F., Mazzucchelli, M.L.Diamond thermoelastic properties and implications for determining the pressure of formation of diamond inclusion systems.Russian Geology and Geophysics, Vol. 56, 1-2, pp. 211-220.TechnologyDiamond inclusions

Abstract: The formation conditions of diamond can be determined from the residual pressure of inclusions trapped within the diamond, as measured at ambient conditions, and the equations of state (EoS) of the mineral inclusion and the host diamond. The EoS parameters of the diamond and the inclusion phase are therefore critical for determining the precision and accuracy of the calculation of formation conditions of diamonds. The questions we address are (i) How precise are these calculations? and, in particular, (ii) Do we know the EoS parameters of diamond to a precision and accuracy which do not contribute significantly to uncertainties in the geological conclusions drawn from these calculations? We present a review of the most recent compressional data, simulations, and direct elastic measurements of diamond and show them to be consistent with a room-temperature bulk modulus of K0T = 444(2) GPa and a pressure derivative K = 4.0. In combination with a thermal-pressure model with parameters aV300,0 = 2.672(3) x 10- 6 K- 1 and a single Einstein temperature 0E = 1500 K, the volume variation of diamond from room conditions to pressures and temperatures exceeding those in the Earth’s transition zone is described to within the levels of uncertainty inherent in both experimental and computational determinations. For the example of olivine inclusions in diamond, these uncertainties in the diamond EoS parameters lead to uncertainties in the entrapment pressures of no more than 0.001 GPa at low temperatures and 0.008 GPa at higher temperatures.
DS201507-0326
2015
Alvaro, M.Milani, S., Nestola, F., Alvaro, M., Pasqual, D., Mazzucchelli, M.L., Domeneghetti, M.C., Geiger, C.A.Diamond -garnet geobarometry: the role of garnet compressibility and expansivity.Lithos, Vol. 227, pp. 140-147.TechnologyGeobarometry
DS201608-1428
2016
Alvaro, M.Nimis, P., Alvaro, M., Nestola, F., Angel, R.J., Marquardt, K., Rustioni, G., Harris, J.W., Marone, F.First evidence of hydrous silicic fluid films around solid inclusions in gem-qualty diamonds.Lithos, Vol. 260, pp. 384-389.Russia, Africa, South AfricaDeposit - Udachnaya, Premier

Abstract: Diamonds form from fluids or melts circulating at depth in the Earth's mantle. Analysis of these fluids is possible if they remain entrapped in the diamond during its growth, but this is rarely observed in gem-quality stones. We provide the first evidence that typical mineral inclusions in gem-quality diamonds from the Siberian and Kaapvaal cratons are surrounded by a thin film of hydrous silicic fluid of maximum thickness 1.5 ?m. The fluid contains Si2O(OH)6, Si(OH)4, and molecular H2O and was identified using confocal micro-Raman spectroscopy and synchrotron-based X-ray tomographic microscopy. As the solid mineral inclusions have both peridotitic and eclogitic affinities and occur in two cratonic regions, our results demonstrate the strong connection between water-rich fluids and the growth of gem-quality lithospheric diamonds. The presence of the fluid films should be taken into account for a proper evaluation of H2O contents in the mantle based on H2O contents in solid inclusions and for a robust assessment of diamond formation pressures based on the residual pressures of the inclusions.
DS201610-1891
2016
Alvaro, M.Nestola, F., Alvaro, M., Casati, M.N., Wilhelm, H., Kleppe, A.K., Jephcoat, A.P., Domeneghetti, M.C., Harris, J.W.Source assemblage types for cratonic diamonds from x-ray synchroton diffraction.Lithos, in press available 5p.RussiaDeposit - Udachnaya
DS201611-2116
2016
Alvaro, M.Jones, A.P., McMillan, P.F., Salzmann, C.G., Alvaro, M., Nestola, F., Prencipe, M., Dobson, D., Hazael, R., Moore, M.Structural characteristization of natural diamond shocked to 60 Gpa: implications for Earth and Planetary Systems.Lithos, in press available 25p.TechnologyNatural diamonds

Abstract: The possible presence of the high-density carbon polymorph with hexagonal symmetry known as "lonsdaleite" provides an important marker for shock impact events. It is typically considered to form as a metastable phase produced from graphite or other carbonaceous precursors. However, its existence has recently been called into question. Here we collected high-resolution synchrotron X-ray diffraction data for laboratory-shocked and natural impact diamonds that both show evidence for deviations from cubic symmetry, that would be consistent with the appearance of hexagonal stacking sequences. These results show that hexagonality can be achieved by shocking diamond as well as from graphite precursors. The diffraction results are analyzed in terms of a general model that describes intermediate stacking sequences between pure diamond (fully cubic) and "lonsdaleite" (fully hexagonal) phases, with provision made for ordered vs disordered stacking arrangements. This approach provides a "hexagonality index" that can be used to characterize and distinguish among samples that have experienced different degrees of shock or static high pressure-high temperature treatments. We have also examined the relative energetics of diamond and "lonsdaleite" structures using density functional theoretical (DFT) methods. The results set limits on the conditions under which a transformation between diamond and "lonsdaleite" structures can be achieved. Calculated Raman spectra provide an indicator for the presence of extended hexagonal stacking sequences within natural and laboratory-prepared samples. Our results show that comparable crystallographic structures may be developed by impact-generated shockwaves starting from ambient conditions using either of the two different allotropes of carbon (diamond, graphite). This broadens the scope for its occurrence in terrestrial and planetary systems.
DS201701-0016
2016
Alvaro, M.Jones, A.P., McMillan P.F., Salzmann, C.G., Alvaro, M., Nestola, F., Prencipe, M., Dobson, D., Hazael, R., Moore, M.Structual characterization of natural diamond shocked to 60 Gpa; implications for Earth and Planetary Systems.Lithos, In press availableTechnologyDiamond morphology

Abstract: The possible presence of the high-density carbon polymorph with hexagonal symmetry known as “lonsdaleite” provides an important marker for shock impact events. It is typically considered to form as a metastable phase produced from graphite or other carbonaceous precursors. However, its existence has recently been called into question. Here we collected high-resolution synchrotron X-ray diffraction data for laboratory-shocked and natural impact diamonds that both show evidence for deviations from cubic symmetry, that would be consistent with the appearance of hexagonal stacking sequences. These results show that hexagonality can be achieved by shocking diamond as well as from graphite precursors. The diffraction results are analyzed in terms of a general model that describes intermediate stacking sequences between pure diamond (fully cubic) and “lonsdaleite” (fully hexagonal) phases, with provision made for ordered vs disordered stacking arrangements. This approach provides a “hexagonality index” that can be used to characterize and distinguish among samples that have experienced different degrees of shock or static high pressure-high temperature treatments. We have also examined the relative energetics of diamond and “lonsdaleite” structures using density functional theoretical (DFT) methods. The results set limits on the conditions under which a transformation between diamond and “lonsdaleite” structures can be achieved. Calculated Raman spectra provide an indicator for the presence of extended hexagonal stacking sequences within natural and laboratory-prepared samples. Our results show that comparable crystallographic structures may be developed by impact-generated shockwaves starting from ambient conditions using either of the two different allotropes of carbon (diamond, graphite). This broadens the scope for its occurrence in terrestrial and planetary systems.
DS201705-0807
2017
Alvaro, M.Alvaro, M., Angel, R., Nimis, P., Milani, S., Harris, J., Nestola, F.Orientation relationship between diamond and magnesiochromite inclusions.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 12200 AbstractRussiaDeposit - Udachnaya

Abstract: The correct determination of the relative crystallographic orientations of single crystals has many applications. When single crystals undergo phase transitions, especially at high pressures, the relative orientations of the two phases yields insights into transition mechanisms (Dobson et al 2013). On the other hand, determination of the crystallographic orientations of minerals included in diamonds can provide insights into the mechanisms of their entrapment and the timing of their formation relative to the host diamond (e.g. Nestola et al. 2014, Milani et al. 2016). The reported occurrence of non-trivial orientations for some minerals in diamonds, suggesting an epitaxial relationship, has long been considered to reflect contemporaneous growth of the diamond and the inclusion (e.g. syngenesis). Correct interpretation of such orientations requires (i) a statistically significant crystallographic data set for single and multiple inclusions in a large number of diamonds, and (ii) a robust data-processing method, capable of removing ambiguities derived from the high symmetry of the diamond and the inclusion. We have developed a software to perform such processing (OrientXplot, Angel et al. 2015), starting from crystallographic orientation matrixes obtained by X-ray diffractometry or EBSD data. Previous studies of inclusions in lithospheric diamonds, by single-crystal X-ray diffraction and EBSD, indicate a wide variety in the orientations of different inclusion phases with respect to their diamond host (Futergendler & Frank-Kamenetsky 1961; Frank-Kamenetsky 1964; Wiggers de Vries et al. 2011; Nestola et al. 2014, Milani et al. 2016). For example, olivine inclusions in lithospheric diamonds from Udachnaya do not show any preferred orientations with respect to their diamond hosts, but multiple inclusions in a single diamond often show very similar orientations within few degrees. In the present work on magnesiochromite inclusions in diamonds from Udachnaya, there is a partial orientation between inclusion and host. A (111) plane of each inclusion is sub-parallel to a {111} plane of their diamond host, but with random orientations of the magnesiochromite [100], [010] and [001] relative to the diamond. In one case, where a single inclusion comprised a magnesiochromite-olivine touching pair, the magnesiochromite was oriented as noted above and the olivine showed a random orientation. The implications of these observations for the mechanisms of diamond growth will be explored and the results will be compared and combined with previous work.
DS201705-0838
2017
Alvaro, M.Jones, A., Alvaro, M., McMillan, P., Price, D., Milledge, J.Lonsdaleite signatures and shock remnants in mantle diamond?European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 16597 AbstractChinaDeposit - Liaoning
DS201709-1952
2017
Alvaro, M.Angel, R.J., Alvaro, M., Nestola, F.40 years of mineral elasticity: a critical review and a new parameterisation of equations of state for mantle olivines and diamond inclusions.Physics and Chemistry of Minerals, in press available, 19p.Technologydiamond inclusions

Abstract: Elasticity is a key property of materials, not only for predicting volumes and densities of minerals at the pressures and temperatures in the interior of the Earth, but also because it is a major factor in the energetics of structural phase transitions, surface energies, and defects within minerals. Over the 40 years of publication of Physics and Chemistry of Minerals, great progress has been made in the accuracy and precision of the measurements of both volumes and elastic tensors of minerals and in the pressures and temperatures at which the measurements are made. As an illustration of the state of the art, all available single-crystal data that constrain the elastic properties and pressure–volume–temperature equation of state (EoS) of mantle-composition olivine are reviewed. Single-crystal elasticity measurements clearly distinguish the Reuss and Voigt bulk moduli of olivine at all conditions. The consistency of volume and bulk modulus data is tested by fitting them simultaneously. Data collected at ambient pressure and data collected at ambient temperature up to 15 GPa are consistent with a Mie–Grünesien–Debye thermal-pressure EoS in combination with a third-order Birch–Murnaghan (BM) compressional EoS, the parameter V0 = 43.89 cm3 mol?1, isothermal Reuss bulk modulus KTR,0=126.3(2) GPaKTR,0=126.3(2) GPa, K?TR,0=4.54(6)KTR,0?=4.54(6), a Debye temperature ?D=644(9)K?D=644(9)K, and a Grüneisen parameter ?0 = 1.044(4), whose volume dependence is described by q = 1.9(2). High-pressure softening of the bulk modulus at room temperature, relative to this EoS, can be fit with a fourth-order BM EoS. However, recent high-P, T Brillouin measurements are incompatible with these EoS and the intrinsic physics implied by it, especially that (?K?TR?T)P>0(?KTR??T)P>0. We introduce a new parameterisation for isothermal-type EoS that scales both the Reuss isothermal bulk modulus and its pressure derivative at temperature by the volume, KTR(T,P=0)=KTR,0[V0V(T)]?TKTR(T,P=0)=KTR,0[V0V(T)]?T and K?TR(T,P=0)=K?TR,0[V(T)V0]??KTR?(T,P=0)=KTR,0?[V(T)V0]??, to ensure thermodynamic correctness at low temperatures. This allows the elastic softening implied by the high-P, T Brillouin data for mantle olivine to be fit simultaneously and consistently with the same bulk moduli and pressure derivatives (at room temperature) as the MGD EoS, and with the additional parameters of ?V0 = 2.666(9) × 10?5 K?1, ?E=484(6)?E=484(6), ?T?T = 5.77(8), and ???? = ?3.5(1.1). The effects of the differences between the two EoS on the calculated density, volume, and elastic properties of olivine at mantle conditions and on the calculation of entrapment conditions of olivine inclusions in diamonds are discussed, and approaches to resolve the current uncertainties are proposed.
DS201712-2672
2017
Alvaro, M.Angel, R.J., Mazzucchelli, M.L., Alvaro, M., Nestola, F.EosFit-Pinc: a simple GUI for host inclusion elastic thermobarometry.American Mineralogist, Vol. 102, pp. 1957-1960.Technologygeobarometry

Abstract: Elastic geothermobarometry is a method of determining metamorphic conditions from the excess pressures exhibited by mineral inclusions trapped inside host minerals. An exact solution to the problem of combining non-linear Equations of State (EoS) with the elastic relaxation problem for elastically isotropic spherical host-inclusion systems without any approximations of linear elasticity is presented. The solution is encoded into a Windows GUI program EosFit-Pinc. The program performs host-inclusion calculations for spherical inclusions in elastically isotropic systems with full P-V-T EoS for both phases, with a wide variety of EoS types. The EoS values of any minerals can be loaded into the program for calculations. EosFit-Pinc calculates the isomeke of possible entrapment conditions from the pressure of an inclusion measured when the host is at any external pressure and temperature (including room conditions), and it can calculate final inclusion pressures from known entrapment conditions. It also calculates isomekes and isochors of the two phases.
DS201712-2673
2016
Alvaro, M.Angel, R.J., Milani, S., Alvaro, M., Nestola, F.High quality structures at high pressure? Insights from inclusions in diamonds.Zeitschrfit fur Kristallographie, Vol. 231, pp. 467-473.Technologydiamond inclusions

Abstract: We describe the experimental protocols necessary to measure the crystal structures of minerals trapped within diamonds by single-crystal X-ray diffraction to the same quality as obtained from minerals studied at ambient conditions. The results show that corrections for X-ray absorption in complex cases can be made with good precision. Comparison of the refined structure of a single-crystal olivine inclusion inside a diamond with the structure of a similar olivine held in a high-pressure diamond-anvil cell shows that data resolution, not the correction for absorption effects, is the dominant factor in influencing the quality of structures determined at high pressures by single-crystal X-ray diffraction.
DS201712-2687
2016
Alvaro, M.Gonzales-Platas, J., Alvaro, M., Nestola, F., Angel, R.J. .EosFIT7-GUI: a new graphical user interface for equation of state calculations, analyses and teaching.Journal of Applied Crystallography, Vol. 49, pp. 1377-1382.Technologyanalyses

Abstract: EosFit7-GUI is a full graphical user interface designed to simplify the analysis of thermal expansion and equations of state (EoSs). The software allows users to easily perform least-squares fitting of EoS parameters to diffraction data collected as a function of varying pressure, temperature or both. It has been especially designed to allow rapid graphical evaluation of both parametric data and the EoS fitted to the data, making it useful both for data analysis and for teaching.
DS201712-2711
2016
Alvaro, M.Nestola, F., Burnham, A.D., Peruzzo, L., Tauro, L., Alvaro, M., Walter, M.J., Gunter, M., Anzolini, C., Kohn, S.C.Tetragonal almandine-pyrope phase, TAPP: finally a name for it, the new name jeffbenite.Mineralogical Magazine, Vol. 80, pp. 1219-1232.Technologypyrope

Abstract: Jeffbenite, ideally Mg3Al2Si3O8, previously known as tetragonal-almandine-pyrope-phase (‘TAPP’), has been characterized as a new mineral from an inclusion in an alluvial diamond from São Luiz river, Juina district of Mato Grosso, Brazil. Its density is 3.576 g/cm3 and its microhardness is ?7. Jeffbenite is uniaxial (-) with refractive indexes ??=?1.733(5) and ??=?1.721(5). The crystals are in general transparent emerald green. Its approximate chemical formula is (Mg2.62Fe2+0.27)(Al1.86Cr0.16)(Si2.82Al0.18)O12 with very minor amounts of Mn, Na and Ca. Laser ablation ICP-MS showed that jeffbenite has a very low concentration of trace elements. Jeffbenite is tetragonal with space group I4¯2d, cell edges being a?=?6.5231(1) and c?=?18.1756(3) Å. The main diffraction lines of the powder diagram are [d (in Å), intensity, hkl]: 2.647, 100, 2 0 4; 1.625, 44, 3 2 5; 2.881, 24, 2 1 1; 2.220, 19, 2 0 6; 1.390, 13, 4 2 4; 3.069, 11, 2 0 2; 2.056, 11, 2 2 4; 1.372, 11, 2 0 12. The structural formula of jeffbenite can be written as (M1)(M2)2(M3)2(T1)(T2)2O12 with M1 dominated by Mg, M2 dominated by Al, M3 dominated again by Mg and both T1 and T2 almost fully occupied by Si. The two tetrahedra do not share any oxygen with each other (i.e. jeffbenite is classified as an orthosilicate). Jeffbenite was approved as a new mineral by the IMA Commission on New Minerals and Mineral Names with the code IMA 2014-097. Its name is after Jeffrey W. Harris and Ben Harte, two world-leading scientists in diamond research. The petrological importance of jeffbenite is related to its very deep origin, which may allow its use as a pressure marker for detecting super-deep diamonds. Previous experimental work carried out on a Ti-rich jeffbenite establishes that it can be formed at 13 GPa and 1700 K as maximum P-T conditions.
DS201802-0219
2018
Alvaro, M.Anzolini, C., Prencipe, M., Alvaro, M., Romano, C., Vona, A., Lorenzon, S., Smith, E.M., Brenker, F.E., Nestola, F.Depth of formation of super deep diamonds: Raman barometry of CaSiO3 walstromite inclusions.American Mineralogist, Vol. 103, pp. 69-74.Mantlegeobarometry

Abstract: “Super-deep” diamonds are thought to have a sub-lithospheric origin (i.e., below ~300 km depth) because some of the mineral phases entrapped within them as inclusions are considered to be the products of retrograde transformation from lower-mantle or transition-zone precursors. CaSiO3-walstromite, the most abundant Ca-bearing mineral inclusion found in super-deep diamonds, is believed to derive from CaSiO3-perovskite, which is stable only below ~600 km depth, although its real depth of origin is controversial. The remnant pressure (Pinc) retained by an inclusion, combined with the thermoelastic parameters of the mineral inclusion and the diamond host, allows calculation of the entrapment pressure of the diamond-inclusion pair. Raman spectroscopy, together with X-ray diffraction, is the most commonly used method for measuring the Pinc without damaging the diamond host. In the present study we provide, for the first time, a calibration curve to determine the Pinc of a CaSiO3-walstromite inclusion by means of Raman spectroscopy without breaking the diamond. To do so, we performed high-pressure micro-Raman investigations on a CaSiO3-walstromite crystal under hydrostatic stress conditions within a diamond-anvil cell. We additionally calculated the Raman spectrum of CaSiO3-walstromite by ab initio methods both under hydrostatic and non-hydrostatic stress conditions to avoid misinterpretation of the results caused by the possible presence of deviatoric stresses causing anomalous shift of CaSiO3-walstromite Raman peaks. Last, we applied single-inclusion elastic barometry to estimate the minimum entrapment pressure of a CaSiO3-walstromite inclusion trapped in a natural diamond, which is ~9 GPa (~260 km) at 1800 K. These results suggest that the diamond investigated is certainly sub-lithospheric and endorse the hypothesis that the presence of CaSiO3-walstromite is a strong indication of super-deep origin.
DS201804-0668
2018
Alvaro, M.Alvaro, M., Nestola, F.Crystallographic approaches to study mineral inclusions in diamonds.4th International Diamond School: Diamonds, Geology, Gemology and Exploration Bressanone Italy Jan. 29-Feb. 2nd., pp. 7-8. abstractTechnologydiamond inclusions
DS201804-0669
2018
Alvaro, M.Angel, R.J., Alvaro, M., Nestola, F.40 years of mineral elasticity: a critical review and a new parameterisation of equations of state for mantle olivines and diamond inclusions.Physics and Chemistry of Minerals, Vol. 45, 2, pp. 95-131.Mantleolivines

Abstract: Elasticity is a key property of materials, not only for predicting volumes and densities of minerals at the pressures and temperatures in the interior of the Earth, but also because it is a major factor in the energetics of structural phase transitions, surface energies, and defects within minerals. Over the 40 years of publication of Physics and Chemistry of Minerals, great progress has been made in the accuracy and precision of the measurements of both volumes and elastic tensors of minerals and in the pressures and temperatures at which the measurements are made. As an illustration of the state of the art, all available single-crystal data that constrain the elastic properties and pressure–volume–temperature equation of state (EoS) of mantle-composition olivine are reviewed. Single-crystal elasticity measurements clearly distinguish the Reuss and Voigt bulk moduli of olivine at all conditions. The consistency of volume and bulk modulus data is tested by fitting them simultaneously. Data collected at ambient pressure and data collected at ambient temperature up to 15 GPa are consistent with a Mie–Grünesien–Debye thermal-pressure EoS in combination with a third-order Birch–Murnaghan (BM) compressional EoS, the parameter V 0 = 43.89 cm3 mol?1, isothermal Reuss bulk modulus KTR,0=126.3(2) GPa, K?TR,0=4.54(6), a Debye temperature ?D=644(9)K, and a Grüneisen parameter ? 0 = 1.044(4), whose volume dependence is described by q = 1.9(2). High-pressure softening of the bulk modulus at room temperature, relative to this EoS, can be fit with a fourth-order BM EoS. However, recent high-P, T Brillouin measurements are incompatible with these EoS and the intrinsic physics implied by it, especially that (?K?TR?T)P>0. We introduce a new parameterisation for isothermal-type EoS that scales both the Reuss isothermal bulk modulus and its pressure derivative at temperature by the volume, KTR(T,P=0)=KTR,0[V0V(T)]?T and K?TR(T,P=0)=K?TR,0[V(T)V0]??, to ensure thermodynamic correctness at low temperatures. This allows the elastic softening implied by the high-P, T Brillouin data for mantle olivine to be fit simultaneously and consistently with the same bulk moduli and pressure derivatives (at room temperature) as the MGD EoS, and with the additional parameters of ? V0 = 2.666(9) × 10?5 K?1, ?E=484(6), ?T = 5.77(8), and ?? = ?3.5(1.1). The effects of the differences between the two EoS on the calculated density, volume, and elastic properties of olivine at mantle conditions and on the calculation of entrapment conditions of olivine inclusions in diamonds are discussed, and approaches to resolve the current uncertainties are proposed.-
DS201804-0723
2018
Alvaro, M.Nestola, F., Korolev, N., Kopylova, M., Rotiroti, N., Pearson, D.G., Pamato, M.G., Alvaro, M., Peruzzo, L., Gurney, J.J., Moore, A.E., Davidson, J.CaSiO3 perovskite in diamond indicates the recycling of oceanic crust into the lower mantle.Nature, Vol. 555, March 8, pp. 237-241.Mantledeposit - Cullinan

Abstract: Laboratory experiments and seismology data have created a clear theoretical picture of the most abundant minerals that comprise the deeper parts of the Earth’s mantle. Discoveries of some of these minerals in ‘super-deep’ diamonds—formed between two hundred and about one thousand kilometres into the lower mantle—have confirmed part of this picture1,2,3,4,5. A notable exception is the high-pressure perovskite-structured polymorph of calcium silicate (CaSiO3). This mineral—expected to be the fourth most abundant in the Earth—has not previously been found in nature. Being the dominant host for calcium and, owing to its accommodating crystal structure, the major sink for heat-producing elements (potassium, uranium and thorium) in the transition zone and lower mantle, it is critical to establish its presence. Here we report the discovery of the perovskite-structured polymorph of CaSiO3 in a diamond from South African Cullinan kimberlite. The mineral is intergrown with about six per cent calcium titanate (CaTiO3). The titanium-rich composition of this inclusion indicates a bulk composition consistent with derivation from basaltic oceanic crust subducted to pressures equivalent to those present at the depths of the uppermost lower mantle. The relatively ‘heavy’ carbon isotopic composition of the surrounding diamond, together with the pristine high-pressure CaSiO3 structure, provides evidence for the recycling of oceanic crust and surficial carbon to lower-mantle depths.https://www.nature.com/articles/nature25972
DS201812-2853
2018
Alvaro, M.Murri, M., Mazzucchelli, M.L., Campomenosi, N., Korsakov, A.V., Prencipe, M., Mihailova, B.D., Scambelluri, M., Angel, R.J., Alvaro, M.Raman elastic geobarometry for anisotropic mineral inclusions. MirAmerican Mineralogist, Vol. 103, pp. 1869-1872.Russiamineral inclusions

Abstract: Elastic geobarometry for host-inclusion systems can provide new constraints to assess the pressure and temperature conditions attained during metamorphism. Current experimental approaches and theory are developed only for crystals immersed in a hydrostatic stress field, whereas inclusions experience deviatoric stress. We have developed a method to determine the strains in quartz inclusions from Raman spectroscopy using the concept of the phonon-mode Grüneisen tensor. We used ab initio Hartree-Fock/Density Functional Theory to calculate the wavenumbers of the Raman-active modes as a function of different strain conditions. Least-squares fits of the phonon-wavenumber shifts against strains have been used to obtain the components of the mode Grüneisen tensor of quartz (??m1 and ?m3?) that can be used to calculate the strains in inclusions directly from the measured Raman shifts. The concept is demonstrated with the example of a natural quartz inclusion in eclogitic garnet from Mir kimberlite and has been validated against direct X-ray diffraction measurement of the strains in the same inclusion.
DS201904-0714
2019
Alvaro, M.Anzolini, C., Nestola, F., Mazzucchelli, M.L., Alvaro, M., Nimis, P., Gianese, A., Morganti, S., Marone, F., Campione, M., Hutchison, M.T., Harris, J.W.Depth of diamond formation obtained from single periclase inclusions. SDD ( Super Deep Diamonds)Geology , Vol. 47, 3, pp. 219-222.South America, Brazil, Guyanadiamond genesis

Abstract: Super-deep diamonds (SDDs) are those that form at depths between ?300 and ?1000 km in Earth’s mantle. They compose only 1% of the entire diamond population but play a pivotal role in geology, as they represent the deepest direct samples from the interior of our planet. Ferropericlase, (Mg,Fe)O, is the most abundant mineral found as inclusions in SDDs and, when associated with low-Ni enstatite, which is interpreted as retrogressed bridgmanite, is considered proof of a lower-mantle origin. As this mineral association in diamond is very rare, the depth of formation of most ferropericlase inclusions remains uncertain. Here we report geobarometric estimates based on both elasticity and elastoplasticity theories for two ferropericlase inclusions, not associated with enstatite, from a single Brazilian diamond. We obtained a minimum depth of entrapment of 15.7 (±2.5) GPa at 1830 (±45) K (?450 [±70] km depth), placing the origin of the diamond-inclusion pairs at least near the upper mantle-transition zone boundary and confirming their super-deep origin. Our analytical approach can be applied to any type of mineral inclusion in diamond and is expected to allow better insights into the depth distribution and origin of SDDs.
DS201905-1063
2019
Alvaro, M.Nimis, P., Angel, R.J., Alvaro, M., Nestola, F., Harris, J.W., Casati, N., Marone, F.Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?Contributions to Mineralogy and Petrology, Vol. 174, p. 29- 13p.Russia, Siberiadeposit - Udachnaya

Abstract: We have studied by X-ray diffractometry the crystallographic orientation relationships (CORs) between magnesiochromite (mchr) inclusions and their diamond hosts in gem-quality stones from the mines Udachnaya (Siberian Russia), Damtshaa (Botswana) and Panda (Canada); in total 36 inclusions in 23 diamonds. In nearly half of the cases (n?=?17), [111]mchr is parallel within error to [111]diamond, but the angular misorientation for other crystallographic directions is generally significant. This relationship can be described as a case of rotational statistical COR, in which inclusion and host share a single axis (1 df). The remaining mchr-diamond pairs (n?=?19) have a random COR (2 df). The presence of a rotational statistical COR indicates that the inclusions have physically interacted with the diamond before their final incorporation. Of all possible physical processes that may have influenced mchr orientation, those driven by surface interactions are not considered likely because of the presence of fluid films around the inclusions. Mechanical interaction between euhedral crystals in a fluid-rich environment is therefore proposed as the most likely mechanism to produce the observed rotational COR. In this scenario, neither a rotational nor a random COR can provide information on the relative timing of growth of mchr and diamond. Some multiple, iso-oriented inclusions within single diamonds, however, indicate that mchr was partially dissolved during diamond growth, suggesting a protogenetic origin of these inclusions.
DS201908-1797
2019
Alvaro, M.Murri, M., Smith, R.L., McColl, K., Hart, M., Alvaro, M., Jones, A.P., Nemeth, P., Salzmann, C.G., Cora, F., Domeneghetti, M.C., Nestola, F., Sobolev, N.V., Vishnevsky, S.A., Logvinova, A.M., McMillan, P.F.Quantifying hexagonal stacking in diamond. ( lonsdaleite)Nature Scientific Reports, doi.org/10.1038/ s41598-019-46556-3 8p. PdfGlobaldiamond morphology, impact craters

Abstract: Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs. The structural characterization of such diamonds remains a challenge. Here, impact diamonds from the Popigai crater were characterized with a range of techniques. Using the MCDIFFaX approach for analysing X-ray diffraction data, hexagonality indices up to 40% were found. The effects of increasing amounts of hexagonal stacking on the Raman spectra of diamond were investigated computationally and found to be in excellent agreement with trends in the experimental spectra. Electron microscopy revealed nanoscale twinning within the cubic diamond structure. Our analyses lead us to propose a systematic protocol for assigning specific hexagonality attributes to the mineral designated as lonsdaleite among natural and synthetic samples.
DS201909-2076
2019
Alvaro, M.Piazzi, M., Morana, M., Coisson, M., Marone, F., Campione, M., Bindi, L., Jones, A.P., Ferrara, E., Alvaro, M.Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds.Diamonds and Related Materials, in press available 36p. PdfAfrica, Ghanadeposit - Akwatia

Abstract: Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possibility is related to their capability to carry a remanent magnetization dependent on their magnetic history. However, comprehensive experimental studies on magnetic inclusions in diamonds have been rarely reported so far. Here we exploit X-ray diffraction, Synchrotron-based X-ray Tomographic Microscopy and Alternating Field Magnetometry to determine the crystallographic, morphological and magnetic properties of ferrimagnetic Fe-oxides entrapped in diamonds coming from Akwatia (Ghana). We exploit the methodology to estimate the natural remanence of the inclusions, associated to the Earth's magnetic field they experienced, and to get insights on the relative time of formation between host and inclusion systems. Furthermore, from the hysteresis loops and First Order Reversal Curves we determine qualitatively the anisotropy, size and domain state configuration of the magnetic grains constituting the inclusions.
DS201910-2292
2019
Alvaro, M.Piazzi, M., Morana, M., Coisson, M., Marone, F., Campione, M., Bindi, L., Jones, A.P., Ferrara, E., Alvaro, M.Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds. Akwatiaresearchgate.net, June 18, 333866141 12p. PdfAfrica, Ghanadeposit - Akwatia

Abstract: Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possibility is related to their capability to carry a remanent magnetization dependent on their magnetic history. However, comprehensive experimental studies on magnetic inclusions in diamonds have been rarely reported so far. Here we exploit X-ray diffraction, Synchrotron-based X-ray Tomographic Microscopy and Alternating Field Magnetometry to determine the crystallographic, morphological and magnetic properties of ferrimagnetic Fe-oxides entrapped in diamonds coming from Akwatia (Ghana). We exploit the methodology to estimate the natural remanence of the inclusions, associated to the Earth's magnetic field they experienced, and to get insights on the relative time of formation between host and inclusion systems. Furthermore, from the hysteresis loops and First Order Reversal Curves we determine qualitatively the anisotropy, size and domain state configuration of the magnetic grains constituting the inclusions.
DS201912-2768
2019
Alvaro, M.Alvaro, M., Mazzucchelli, M.L., Angel, R.J., Murri, M., Campmenosi, N., Scambelluri, M., Nestola, F., Korsakov, A., Tomilenko, A.A., Marone, F., Morana, M.Fossil subduction recorded by quartz from the coesite stability field. GeobarometryGeology, in press, 5p. PdfRussia, Yakutiadeposit - Mir

Abstract: Metamorphic rocks are the records of plate tectonic processes whose reconstruction relies on correct estimates of the pressures and temperatures (P-T) experienced by these rocks through time. Unlike chemical geothermobarometry, elastic geobarometry does not rely on chemical equilibrium between minerals, so it has the potential to provide information on overstepping of reaction boundaries and to identify other examples of non-equilibrium behavior in rocks. Here we introduce a method that exploits the anisotropy in elastic properties of minerals to determine the unique P and T of entrapment from a single inclusion in a mineral host. We apply it to preserved quartz inclusions in garnet from eclogite xenoliths hosted in Yakutian kimberlites (Russia). Our results demonstrate that quartz trapped in garnet can be preserved when the rock reaches the stability field of coesite (the high-pressure and high-temperature polymorph of quartz) at 3 GPa and 850 °C. This supports a metamorphic origin for these xenoliths and sheds light on the mechanisms of craton accretion from a subducted crustal protolith. Furthermore, we show that interpreting P and T conditions reached by a rock from the simple phase identification of key inclusion minerals can be misleading.
DS201912-2804
2019
Alvaro, M.Mazzucchelli, M.L., Reali, A., Morganti, S., Angel, R.J., Alvaro, M.Elastic geobarometry for anistropic inclusions in cubic hosts. ( not specific to diamonds)Lithos, Vol. 350-351, 105218 11p. PdfMantlegeobarometry

Abstract: Mineral inclusions entrapped in other minerals may record the local stresses at the moment of their entrapment in the deep Earth. When rocks are exhumed to the surface of the Earth, residual stresses and strains may still be preserved in the inclusion. If measured and interpreted correctly through elastic geobarometry, they give us invaluable information on the pressures (P) and temperatures (T) of metamorphism. Current estimates of P and T of entrapment rely on simplified models that assumes that the inclusion is spherical and embedded in an infinite host, and that their elastic properties are isotropic. We report a new method for elastic geobarometry for anisotropic inclusions in quasi-isotropic hosts. The change of strain in the inclusion is modelled with the axial equations of state of the host and the inclusion. Their elastic interaction is accounted for by introducing a 4th rank tensor, the relaxation tensor, that can be evaluated numerically for any symmetry of the host and the inclusion and for any geometry of the system. This approach can be used to predict the residual strain/stress state developed in an inclusion after exhumation from known entrapment conditions, or to estimate the entrapment conditions from the residual strain measured in real inclusions. In general, anisotropic strain and stress states are developed in non-cubic mineral inclusions such as quartz and zircon, with deviatoric stresses typically limited to few kbars. For garnet hosts, the effect of the mutual crystallographic orientation between the host and the inclusion on the residual strain and stress is negligible when the inclusion is spherical and isolated. Assuming external hydrostatic conditions, our results suggest that the isotropic and the new anisotropic models give estimations of entrapment conditions within 2%.
DS202007-1123
2020
Alvaro, M.Anzolini, C., Siva-Jothy, W., Locock, A.J., Nestola, F., Balic-Zunic, T., Alvaro, M., Stachel, T., Pearson, D.G.Heamanite-(Ce) (K0.5Ce0.5)Ti03 Mineralogical Magazine reports CNMNC Newsletter , No. 55, Vol. 84, https://doi.org/ 10.1180/mgm. 2020.39Canada, Northwest Territoriesdeposit - Gahcho Kue
DS202011-2054
2020
Alvaro, M.Murri, M., Smith, R.L., McColl, K., Hart, M., Alvaro, M., Jones, A.P., Nemeth, P., Salzmann, C.G., Cora, F., Domeneghetti, M.C., Nestola, F., Sobolev, N.V., Vishnevsky, S.A., Logvinova, A.M., McMillan, P.F.Quantifying hexagonal stacking in diamond.Nature/scientific reports, 8p. PdfGlobalcrystallography

Abstract: Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs. The structural characterization of such diamonds remains a challenge. Here, impact diamonds from the Popigai crater were characterized with a range of techniques. Using the MCDIFFaX approach for analysing X-ray diffraction data, hexagonality indices up to 40% were found. The effects of increasing amounts of hexagonal stacking on the Raman spectra of diamond were investigated computationally and found to be in excellent agreement with trends in the experimental spectra. Electron microscopy revealed nanoscale twinning within the cubic diamond structure. Our analyses lead us to propose a systematic protocol for assigning specific hexagonality attributes to the mineral designated as lonsdaleite among natural and synthetic samples.
DS202105-0781
2021
Alvaro, M.Pamato, M.G., Novella, D., Jacobs, D.E., Oliveira, B., Pearson, D.G., Greene, S., Alfonso, J.C., Favero, M., Stachel, T., Alvaro, M., Nestola, F.Protogenetic sulfide inclusions in diamonds date the diamond formation event using Re-Os isotopes. Victor, JerichoGeology , Vol. 49, 4, 5p. Canada, Ontario, Nunavutdiamond inclusions

Abstract: Sulfides are the most abundant inclusions in diamonds and a key tool for dating diamond formation via Re-Os isotopic analyses. The manner in which fluids invade the continental lithospheric mantle and the time scale at which they equilibrate with preexisting (protogenetic) sulfides are poorly understood yet essential factors to understanding diamond formation and the validity of isotopic ages. We investigated a suite of sulfide-bearing diamonds from two Canadian cratons to test the robustness of Re-Os in sulfide for dating diamond formation. Single-crystal X-ray diffraction (XRD) allowed determination of the original monosulfide solid-solution (Mss) composition stable in the mantle, indicating subsolidus conditions of encapsulation, and providing crystallographic evidence supporting a protogenetic origin of the inclusions. The results, coupled with a diffusion model, indicate Re-Os isotope equilibration is sufficiently fast in sulfide inclusions with typical grain size, at mantle temperatures, for the system to be reset by the diamond-forming event. This confirms that even if protogenetic, the Re-Os isochrons defined by these minerals likely reflect the ages of diamond formation, and this result highlights the power of this system to date the timing of fluid migration in mantle lithosphere.
DS202108-1272
2021
Alvaro, M.Barbaro, B.A., Domeneghetti, M.C., Litasov, K.D., Ferriere, L., Pittarello, L., Christ, O., Lorenzon, S., Alvaro, M., Nestola, F.Origin of micrometer-sized impact diamonds in urelilites by catalytic growth involving Fe-Ni-silicide: the example of Kenna meteorite.Geochimica et Cosmochimica Acta, doi.org/10.1016/j.gca.2021.06.022 31p. PdfGlobalmeteorite

Abstract: The occurrence of shock-induced diamonds in ureilite meteorites is common and is used to constrain the history of the ureilite parent bodies. We have investigated a fragment of the Kenna ureilite by micro-X-ray diffraction, micro-Raman spectroscopy and scanning electron microscopy to characterize its carbon phases. In addition to olivine and pigeonite, within the carbon-bearing areas, we identified microdiamonds (up to about 10 ?m in size), nanographite and magnetite. The shock features observed in the silicate minerals and the presence of microdiamonds and nanographite indicate that Kenna underwent a shock event with a peak pressure of at least 15 GPa. Temperatures estimated using a graphite geothermometer are close to 1180 °C. Thus, Kenna is a medium-shocked ureilite, yet it contains microdiamonds, which are typically found in highly shocked carbon-bearing meteorites, instead of the more common nanodiamonds. This can be explained by a relatively long shock event duration (in the order of 4-5 s) and/or by the catalytic effect of Fe-Ni alloys known to favour the crystallization of diamonds. For the first time in a ureilite, carletonmooreite with formula Ni3Si and grain size near 4-7 nm, was found. The presence of nanocrystalline carletonmooreite provides further evidence to support the hypothesis of the catalytic involvement of Fe-Ni bearing phases into the growth process of diamond from graphite during shock events in the ureilite parent body, enabling the formation of micrometer-sized diamond crystals.
DS2002-1326
2002
Alvaro PintoRelvas, J.M.R.S., Barriga, Alvaro Pinto, Ferreira, et al.The Neves Corvo deposit, Iberian pyrite belt: impacts and future, 25 years after the discovery.Society of Economic Geologists Special Publication, No.9,pp.155-76.PortugalCopper, massive sulphide, Deposit - Neves Corvo
DS201608-1419
2016
Alves, E.Maia, M., Sichel, S., Briais, A., Brunelli, D., Ligi, M., Ferreira, N., Campos, T., Mougel, B., Brehme, I., Hemond, C., Motoki, A., Moura, D., Scalabrin, C., Pessanha, I., Alves, E., Ayres, A., Oliveira, P.Extreme mantle uplift and exhumation along a transpressive transform fault.Nature Geoscience, Vol. 9, 8, pp. 619-623.MantleRidges

Abstract: Mantle exhumation at slow-spreading ridges is favoured by extensional tectonics through low-angle detachment faults1, 2, 3, 4, and, along transforms, by transtension due to changes in ridge/transform geometry5, 6. Less common, exhumation by compressive stresses has been proposed for the large-offset transforms of the equatorial Atlantic7, 8. Here we show, using high-resolution bathymetry, seismic and gravity data, that the northern transform fault of the St Paul system has been controlled by compressive deformation since ~10?million years ago. The long-lived transpression resulted from ridge overlap due to the propagation of the northern Mid-Atlantic Ridge segment into the transform domain, which induced the migration and segmentation of the transform fault creating restraining stepovers. An anticlockwise change in plate motion at ~11?million years ago5 initially favoured extension in the left-stepping transform, triggering the formation of a transverse ridge, later uplifted through transpression, forming the St Peter and St Paul islets. Enhanced melt supply at the ridge axis due to the nearby Sierra Leone thermo chemical anomaly9 is responsible for the robust response of the northern Mid-Atlantic Ridge segment to the kinematic change. The long-lived process at the origin of the compressive stresses is directly linked to the nature of the underlying mantle and not to a change in the far-field stress regime.
DS2003-0011
2003
Alves, P.R.Alves, P.R.New dat a on the mineralogy and petrogenesis of the Jacupiranga carbonatites, BrazilSeg Newsletter, No. 55, Oct. p. 8 - brief mentionBrazilBrief mention of research project
DS200412-0022
2003
Alves, P.R.Alves, P.R.New dat a on the mineralogy and petrogenesis of the Jacupiranga carbonatites, Brazil, and the application to mineral processing.SEG Newsletter, No. 55, Oct. p. 8 - brief mentionSouth America, BrazilBrief - research
DS2000-0057
2000
Alves Da SilvaBarbosa, J.S.F., Sabate, Alves Da SilvaGeological and geochronological features of the four Archean crustal segments of Sao Francisco Craton, BahiaIgc 30th. Brasil, Aug. abstract only 1p.Brazil, BahiaTectonics, Craton - Sao Francisco
DS201112-0209
2010
Alves da Silva, E.F.Costa Cavalcante de Souza, L.F., Alves da Silva, E.F.Os kimberlitos da Chapada diamantin a - Bahia conhecimento atual e perspectivas.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 72.South America, Brazil, BahiaOverview of area
DS2000-0213
2000
Alvesm P.H.De Carvalho, H., Tassinari, C., Alvesm P.H., GuimaraesGeochronological review of the Precambrian in western Angola: links with Brasil.Journal of African Earth Sciences, Vol. 31, No. 2, Aug. pp. 383-402.Angola, BrazilGeochronology, Tectonics - Congo, Sao Francisco Craton
DS200812-0024
2008
Alvey, A.Alvey, A., Gaina, C.,Kusznir, N.J., Torsvik, T.H.Integrated crustal thickness mapping and plate reconstructions for the high Arctic.Earth and Planetary Science Letters, In press availableCanada, Arctic, GreenlandTectonics, plate, lithosphere
DS201012-0501
2010
Alvi, S.H.Mir, A.R., Alvi, S.H., Balaram, A.V.Geochemistry of mafic dikes in the Singhbhum Orissa craton: implications for subuction related metasomatism of the mantle beneath the eastern Indian craton.International Geology Review, Vol. 52, 1, pp. 79-94.IndiaSubduction
DS200412-0023
2004
Alvin, M.P.Alvin, M.P., Dunphy, J.M., Groves, D.I.Nature and genesis of a carbonatite associated fluorite deposit at Speewash, East Kimberley region, western Australia.Mineralogy and Petrology, Vol. 80, 3-4, March pp. 127-153.AustraliaCarbonatite
DS2002-1526
2002
AlymovaSoloveva, L.V., Kostrovitskii, S.I., Ukhanov, A.V., Suvorova, L.F., AlymovaMegacrystalline orthopyroxenite with graphite from the Udachanaya pipe, YakutiaDoklady, Vol.385,June-July, pp. 589-92.Russia, YakutiaMineralogy, Deposit - Udachnaya
DS200712-0032
2007
AlymovaAshchepkov, I.V., Pokhilenko, N.P., Logvinova, A.M., Vladykin, N.P., Rotman, Palessky, Alymova, VishnyakovaEvolution of kimberlite magmatic sources beneath Siberia.Plates, Plumes, and Paradigms, 1p. abstract p. A39.RussiaMir
DS200812-0052
2007
AlymovaAshchepkov, I.V., Vladykin, Pkhilenko, Logvinova, Palessky, Afansiev, Alymova, Stegnitsky, Khmelnikova RotamanVariations of ilmenite compositions from Yakutian kimberlites and the problem of their origin.Vladykin Volume 2007, pp. 71-89.Russia, YakutiaIlmenite, kimberlite
DS200812-0053
2008
AlymovaAshchepkov, Pokhilenko, Vladykon, Loginova, Rotman, Afansiev, Kuligin, Malygina, Alymova, Stegnitsky, KhmetnikovaPlume interaction and evolution of the continental mantle lithosphere.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 104-121.MantlePlume
DS200912-0016
2009
AlymovaAschepokov, L., Logvinova, A., Kuligin, Pokhilenko, Vladykin, Mityukhin, Alymova, Malygina, VishnyakovaClinopyroxene eclogite peridotite thermobarometry of the large Yakutian kimberlite pipes.Goldschmidt Conference 2009, p. A58 Abstract.Russia, YakutiaThermobarometry
DS201012-0018
2010
AlymovaAshchepkov, I.V., Pokhilenko, Vladykin, Logvinova, Afansiev, Kuligin, Malygina, Alymova, KostrovitskyStructure and evolution of the lithospheric mantle beneath Siberian Craton, theromobarometric study.Tectonophysics, Vol. 485, pp. 17-41.RussiaGeothermometry
DS201012-0020
2009
AlymovaAshchepkov, Vladykin, Pokhilenko, Logvinova, Kuligin, Pokhilenko, Malgina, Alymova, Mityukhin, KopylovaApplication of the monomineral thermobarometers for the reconstruction of the mantle lithosphere structure.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., p. 98-116.MantleGeothermometry
DS200812-0597
2008
Alymova, N.A.Kostrovitsky, S.A.I.A., Alymova, N.A., Yakolev, D.A.A., Solvaceva, L.A.V.A., Gornova, M.A.A.A.Origin of garnet megacrysts from kimberlites.Doklady Earth Sciences, Vol. 420, 1, pp. 636-640.RussiaPetrology
DS2003-0744
2003
Alymova, N.V.Kostrovitsky, S.I., Alymova, N.V., Ivanov, A.S., Serov, V.P.Structure of the Daldyn field ( Yakutian Province) based on the study of picroilmenite8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractRussia, YakutiaBlank
DS200412-0024
2004
Alymova, N.V.Alymova, N.V., Kostrovitskii, S.I., Ivanov, A.S., Serov, V.P.Picroilmenite from kimberlites of the Daldyn Field, Yakutia.Doklady Earth Sciences, Vol. 395, 4, March-April, pp. 444-447.Russia, YakutiaMineralogy
DS200412-1047
2003
Alymova, N.V.Kostrovitsky, S.I., Alymova, N.V., Ivanov, A.S., Serov, V.P.Structure of the Daldyn field ( Yakutian Province) based on the study of picroilmenite composition.8 IKC Program, Session 7, POSTER abstractRussia, YakutiaKimberlite petrogenesis
DS200812-1285
2008
Alymova, N.V.Yakovlev, D.A., Kostrovitsky, S.I., Alymova, N.V.Mineral composition features from the Upper Muna field, Yakutia.9IKC.com, 3p. extended abstractRussia, YakutiaMineral chemistry - Verhknemunsk
DS201212-0036
2013
Alymova, N.V.Ashchepkov, I.V., Vladykin, N.V., Ntaflos, T., Downes, H., Mitchell, R., Smelov, A.P., Alymova, N.V., Kostrovitsky, S.I., Rotman, A.Ya., Smarov, G.P., Makovchuk, I.V., Stegnitsky, Yu.B., Nigmatulina, E.N., Khmehnikova, O.S.Regularities and mechanism of formation of the mantle lithosphere structure beneath the Siberian Craton in comparison with other cratons.Gondwana Research, Vol. 23, 1, pp. 4-24.Russia, SiberiaKimberlite pipes
DS201212-0376
2012
Alymova, N.V.Kostrovitskii, S.I., Soloveva, L.V., Gornova, M.A., Alymova, N.V., Yakolev, D.A., Ignative, A.V., Velivetskaya, T.A., Suvorova, L.F.Oxygen isotope composition in minerals of mantle parageneses from Yakutian kimberlites.Doklady Earth Sciences, Vol. 444, 1, pp. 579-584.Russia, YakutiaDeposit - Udachnaya, Komsomolskaya
DS201312-0032
2013
Alymova, N.V.Ashchepkov, I.V., Alymova, N.V., Logvinova, A.M., Vladykin, N.V., Kuligin, S.S., Mityukhin, S.I., Stegnitsky, Y.B., Prokopyev, S.A., Salikhov, R.F., Palessky, V.S., Khmelnikova, O.S.Picroilmenites in Yakutian kimberlites: variations and genetic models.Solid Earth, Vol. 5, pp. 1259-1334.Russia, YakutiaDeposits
DS201412-0021
2014
Alymova, N.V.Ashchepkov, I.V., Alymova, N.V., Lognova, A.M., Vladykin, N.V., Kuligin, S.S., Lityukhin, S.I., Downes, H., Stegnitsky, Yu.B., Prokopiev, S.A., Salikhov, R.F., Palessky, V.S., Khmelnikova, O.S.Picroilmenites in Yakutian kimberlites: variations and genetic models.Solid Earth, Vol. 5, pp. 915-938.Russia, YakutiaKimberlite genesis
DS201412-0022
2014
Alymova, N.V.Ashchepkov, I.V., Vladykin, N.N., Ntaflos, T., Kostrovitsky, S.I., Prokopiev, S.A., Downes, H., Smelov, A.P., Agashev, A.M., Logvinova, A.M., Kuligin, S.S., Tychkov, N.S., Salikhov, R.F., Stegnitsky, Yu.B., Alymova, N.V., Vavilov, M.A., Minin, V.A., BabusLayering of the lithospheric mantle beneath the Siberian Craton: modeling using thermobarometry of mantle xenolith and xenocrysts. Tectonophysics, Vol. 634, 5, pp. 55-75.Russia, YakutiaDaldyn, Alakit, Malo-Botuobinsky fields
DS201510-1759
2014
Alymova, N.V.Ashchepkov, I.V., Vladykin, N.V., Ntaflos, T., Logvinova, A.M., Yudin, D.S., Karpenko, M.A., Paleeskiy, V.S., Alymova, N.V., Khmelnikova, O.S.Deep seated xenoliths and xencrysts from Sytykanskaya pipe: evidence for the evolution of the mantle beneath Alakit, Yakutia.Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 203-232.Russia, YakutiaDeposit - Sytykanskaya

Abstract: The concentrate from two phases of the kimberlite (breccia and porphyritic kimberlite) and about 130 xenoliths from the Sytykanskaya pipe of the Alakit field (Yakutia) were studied by EPMA and LAM ICP methods. Reconstructions of the PTXfO2 mantle sections were made separately for the two phases. The porphyritic kimberlites and breccia show differences in the minerals although the layering and pressure interval remains the same. For the porphyritic kimberlite the trends P- Fe# - CaO in garnet, fO2 are sub-vertical while the xenocrysts from the breccia show stepped and curved trends possibly due to interaction with fluids. Minerals within xenoliths show the widest variation in all pressure intervals. PT points for the ilmenites which trace the magmatic system show splitting of the magmatic source into two levels at the pyroxenite lens (4GPa) accompanied by peridotite contamination and an increase in Cr in ilmenites. Two groups of metasomatites with Fe#Ol ~ 10-12% and 13-15% were created by the melts derived from protokimberlites and trace the mantle columns from the lithosphere base (Ilm - Gar - Cr diopside) to Moho becoming essentially pyroxenitic (Cr-diopside with Phl). The first Opx-Gar-based mantle geotherm from the Alakit field has been constructed from15 associations and is close to 35 mw/m2 in the lower part of mantle section but deviates to high temperatures in the upper part of the mantle section. The oxidation state for the protokimberlite melts determined from ilmenites is higher than for the other pipes in the Yakutian kimberlite province which probably accounts for the decrease in the diamond grade of this pipe. The geochemistry of the minerals (garnets and clinopyroxenes) from breccias, metasomatic peridotite xenoliths and pyroxenites systematically differ. Xenocrysts from the breccia were produced by the most differentiated melts and enriched protokimberlite or carbonatite; they show highly inclined nearly linear REE patterns and deep troughs of HFSE. Minerals of the metasomatic xenoliths are less inclined with lower La/Cen ratios and without troughs in spider diagrams. The garnets often show S-shaped patterns. Garnets from the Cr websterites show round REE patterns and deep troughs in Ba-Sr but enrichment in Nb-Ta-U. The clinopyroxenes reveal the inclined and inflected on Gd spectrums with variations in LREE due to AFC differentiation. The 40Ar-39Ar ages for micas from the Alakit field reveal three intervals for the metasomatism. The first (1154 Ma) relates to dispersed phlogopites found throughout the mantle column, and probably corresponds to the continental arc stage in the early stage of Rodinia. Veined highly alkaline and Ti-rich veins with richterite ~1015 Ma corresponds to the plume event within the Rodinia mantle. The ~600-550 Ma stage marks the final Rodinia break-up. The last one near 385 Ma is protokimberlite related.
DS201611-2146
2016
Alymova, N.V.Vladykin, N.V., Alymova, N.V., Perfilev, V.V.Geochemical features of rare metal granites of the Zashikhinsky Massif, East Sayan. ( tantalum)Petrology, Vol. 24, 5, pp. 512-525.Russia, IrkutskRare earths

Abstract: The paper presents detailed geochemical data on the rocks of the Zashikhinsky Massif and mineralogical-geochemical characteristics of the ores of the eponymous deposit. The rare-metal granites are divided into three facies varieties on the basis of the degree of differentiation and ore potential: early facies represented by microcline-albite granites with arfvedsonite, middle facies represented by leucocratic albite-microcline granites, and late (most ore-bearing) facies represented by quartz-albite granites grading into albitites. Microprobe data were obtained on major minerals accumulating trace elements in the rocks and ores. All facies of the rare-metal granites, including the rocks of the fluorite-rare-metal vein, define single compositional trends in the plots of paired correlations of rock-forming and trace elements. In addition, they also show similar REE patterns and spidergrams. The latter, however, differ in the depth of anomalies of some elements. Obtained geological, petrographic, and geochemical data suggest a magmatic genesis of the rocks of different composition and their derivation from a single magma during its differentiation. On the basis of all characteristics, the Zashikhinskoe deposit is estimated as one of the largest tantalum rare-metal deposits of alkaline-granite type in Russia.
DS202010-1829
2013
Alymova, N.V.Ashchepkov, I.V., Alymova, N.V., Loginova, A.M., Vladykin, N.V., Kuligin, S.S., Mityukhin, S.I., Stegnitsky, Y.B., Prokopiev, S.A., Salikhov, R.F., Palessky, V.S., Khmelnikova, O.S.Picroilmenites in Yakutian kimberlites: variations and genetic models. Solid Earth Discussions, Vol. 5, pp. 1-75. pdf * note dateRussia, Yakutiapicroilmenites

Abstract: Major and trace element variations in picroilmenites from Late Devonian kimberlite pipes in Siberia reveal similarities within the region in general, but show individual features for ilmenites from different fields and pipes. Empirical ilmenite thermobarometry (Ashchepkov et al., 2010), as well as common methods of mantle thermobarometry and trace element geochemical modeling, shows long compositional trends for the ilmenites. These are a result of complex processes of polybaric fractionation of protokimberlite melts, accompanied by the interaction with mantle wall rocks and dissolution of previous wall rock and metasomatic associations. Evolution of the parental magmas for the picroilmenites was determined for the three distinct phases of kimberlite activity from Yubileynaya and nearby Aprelskaya pipes, showing heating and an increase of Fe# (Fe# = Fe / (Fe + Mg) a.u.) of mantle peridotite minerals from stage to stage and splitting of the magmatic system in the final stages. High-pressure (5.5-7.0 GPa) Cr-bearing Mg-rich ilmenites (group 1) reflect the conditions of high-temperature metasomatic rocks at the base of the mantle lithosphere. Trace element patterns are enriched to 0.1-10/relative to primitive mantle (PM) and have flattened, spoon-like or S- or W-shaped rare earth element (REE) patterns with Pb > 1. These result from melting and crystallization in melt-feeding channels in the base of the lithosphere, where high-temperature dunites, harzburgites and pyroxenites were formed. Cr-poor ilmenite megacrysts (group 2) trace the high-temperature path of protokimberlites developed as result of fractional crystallization and wall rock assimilation during the creation of the feeder systems prior to the main kimberlite eruption. Inflections in ilmenite compositional trends probably reflect the mantle layering and pulsing melt intrusion during melt migration within the channels. Group 2 ilmenites have inclined REE enriched patterns (10-100)/PM with La / Ybn ~ 10-25, similar to those derived from kimberlites, with high-field-strength elements (HFSE) peaks (typical megacrysts). A series of similar patterns results from polybaric Assimilation + fractional crystallization (AFC) crystallization of protokimberlite melts which also precipitated sulfides (Pb < 1) and mixed with partial melts from garnet peridotites. Relatively low-Ti ilmenites with high-Cr content (group 3) probably crystallized in the metasomatic front under the rising protokimberlite source and represent the product of crystallization of segregated partial melts from metasomatic rocks. Cr-rich ilmenites are typical of veins and veinlets in peridotites crystallized from highly contaminated magma intruded into wall rocks in different levels within the mantle columns. Ilmenites which have the highest trace element contents (1000/PM) have REE patterns similar to those of perovskites. Low Cr contents suggest relatively closed system fractionation which occurred from the base of the lithosphere up to the garnet-spinel transition, according to monomineral thermobarometry for Mir and Dachnaya pipes. Restricted trends were detected for ilmenites from Udachnaya and most other pipes from the Daldyn-Alakit fields and other regions (Nakyn, Upper Muna and Prianabarie), where ilmenite trends extend from the base of the lithosphere mainly up to 4.0 GPa. Interaction of the megacryst forming melts with the mantle lithosphere caused heating and HFSE metasomatism prior to kimberlite eruption.
DS202112-1919
2021
Alymova, N.V.Ashchepkov, I.V., Alymova, N.V., Loginova, A.M., Vladykin, N.V.. Kuligin, S.S., Mityukhin, S.I., Stegnitsky, Y.B., Prokopiev, S.A.Picroilmenites in Yakutian kimberlites: variations and genetic models.Lithos, Vol. 406-407. doi: 10.1016/j.lithos.2021.106499 77p. PdfRussiakimberlite genesis

Abstract: Major and trace element variations in picroilmenites from Late Devonian kimberlite pipes in Siberia reveal similarities within the region in general, but show individual features for ilmenites from different fields and pipes. Empirical ilmenite thermobarometry (Ashchepkov et al., 2010), as well as common methods of mantle thermobarometry and trace element geochemical modeling, shows long compositional trends for the ilmenites. These are a result of complex processes of polybaric fractionation of protokimberlite melts, accompanied by the interaction with mantle wall rocks and dissolution of previous wall rock and metasomatic associations. Evolution of the parental magmas for the picroilmenites was determined for the three distinct phases of kimberlite activity from Yubileynaya and nearby Aprelskaya pipes, showing heating and an increase of Fe# (Fe# = Fe / (Fe + Mg) a.u.) of mantle peridotite minerals from stage to stage and splitting of the magmatic system in the final stages. High-pressure (5.5–7.0 GPa) Cr-bearing Mg-rich ilmenites (group 1) reflect the conditions of high-temperature metasomatic rocks at the base of the mantle lithosphere. Trace element patterns are enriched to 0.1–10/relative to primitive mantle (PM) and have flattened, spoon-like or S- or W-shaped rare earth element (REE) patterns with Pb > 1. These result from melting and crystallization in melt-feeding channels in the base of the lithosphere, where high-temperature dunites, harzburgites and pyroxenites were formed. Cr-poor ilmenite megacrysts (group 2) trace the high-temperature path of protokimberlites developed as result of fractional crystallization and wall rock assimilation during the creation of the feeder systems prior to the main kimberlite eruption. Inflections in ilmenite compositional trends probably reflect the mantle layering and pulsing melt intrusion during melt migration within the channels. Group 2 ilmenites have inclined REE enriched patterns (10–100)/PM with La / Ybn ~ 10–25, similar to those derived from kimberlites, with high-field-strength elements (HFSE) peaks (typical megacrysts). A series of similar patterns results from polybaric Assimilation + fractional crystallization (AFC) crystallization of protokimberlite melts which also precipitated sulfides (Pb < 1) and mixed with partial melts from garnet peridotites. Relatively low-Ti ilmenites with high-Cr content (group 3) probably crystallized in the metasomatic front under the rising protokimberlite source and represent the product of crystallization of segregated partial melts from metasomatic rocks. Cr-rich ilmenites are typical of veins and veinlets in peridotites crystallized from highly contaminated magma intruded into wall rocks in different levels within the mantle columns. Ilmenites which have the highest trace element contents (1000/PM) have REE patterns similar to those of perovskites. Low Cr contents suggest relatively closed system fractionation which occurred from the base of the lithosphere up to the garnet–spinel transition, according to monomineral thermobarometry for Mir and Dachnaya pipes. Restricted trends were detected for ilmenites from Udachnaya and most other pipes from the Daldyn–Alakit fields and other regions (Nakyn, Upper Muna and Prianabarie), where ilmenite trends extend from the base of the lithosphere mainly up to 4.0 GPa. Interaction of the megacryst forming melts with the mantle lithosphere caused heating and HFSE metasomatism prior to kimberlite eruption.
DS201503-0164
2015
Amaike, Y.Ohtani, E., Amaike, Y., Kamada, S., Sakamaki, T., Hirao, N.Stability of hydrous phase H MgSi04H2 under lower mantle conditions.Geophysical Research Letters, Vol. 41, 23, pp. 8283-8287.MantleMineralogy
DS200512-0081
2005
Amakali, M.Bethune, S., Amakali, M., Roberts, K.Review of Namibian legislation and policies pertinent to environmental flows.Physics and Chemistry of the Earth Parts A,B,C, in pressAfrica, NamibiaLegal, geomorphology, water requirements, ecosystems
DS201804-0729
2018
Aman, H.Plakhotnik, T., Aman, H.NV centers in nanodiamonds: how good they are.Diamond & Related Materials, Vol. 82, pp. 87-95.Technologynanodiamonds

Abstract: This paper presents a method for determination of the size distribution for diamond nanocrystals containing luminescent nitrogen-vacancy (NV) centers using the luminescence intensity only. We also revise the basic photo physical properties of NV centers and conclude that the luminescence quantum yield of such centers is significantly smaller than the frequently stated 100\%. The yield can be as low as 5\% for centers embedded in nanocrystals and depends on their shape and the refractive index of the surrounding medium. The paper also addresses the value of the absorption cross-section of NV centers.
DS200812-0025
2008
Amand, M.Amand, M., Terada, K., Osborne, I., Chalapathi Rao, N.V., Dongre, A.SHRIMP U- Pb dating of perovskite from southern Indian kimberlites.9IKC.com, 3p. extended abstractIndiaGeochronology
DS200512-0013
2004
Amankwah, R.K.Amankwah, R.K., Anim Sackey, C.Strategies for sustainable development of small scale gold and diamond mining of Ghana.Resources Policy, Vol. 29, 3-4, pp. 131-138.Africa, GhanaEconomics - sustainable
DS200912-0666
2009
Amarai, W.S.Sarava dos Santos, T.J., Garcia, M.M., Amarai, W.S., Caby, R., Wernick, E., Arthaud, M.H., Dantas, E.L., Santosh, M.Relics of eclogite facies assemblages in the Ceara central domain, NW Borborema Province, NE Brazil: implications for the assembly of West Gondwana.Gondwana Research, Vol. 15, 3-4, pp. 454-470.South America, BrazilTectonics
DS1997-0025
1997
Amaral, G.Amaral, G., Born, H., Tello, S.C.A.Fission track analysis of apatites from Sao Francisco craton and Mesozoic alkaline - carbonatite complexes...Journal of South American Earth Sciences, Vol. 10, No. 3-4, pp. 285-294.Brazil, southeastCarbonatite
DS2002-0457
2002
Amaral, G.Fernandes, A.J., Amaral, G.Cenozoic tectonic events at the border of the Parana Basin, Sao Paulo, BrasilJournal of South American Earth Sciences, Vol.14,8,March pp. 911-31.Brazil, Sao PauloTectonics
DS201907-1565
2019
Amaral, W.S.Oliveira, E.P., Talavera, C., Windley, B.F., Zhao, L., Semprich, J.J., McNaughton, N.J., Amaral, W.S., Sombini, G., Navarro, M., Silva, D.Mesoarchean ( 2820 Ma )high pressure mafic granulite at Uaus, Sao Francisco craton, Brazil, and its potential significance for the assembly of Archean supercraton.Precambrian Research, Vol. 331, 105266 20p.South America, Brazilcraton
DS1994-0961
1994
Amaratunga, D.Kumar, R., Amaratunga, D.Government policies towards small scale miningResources Policy, Vol. 20, No. 1, March pp. 15-22GlobalEconomics, Small scale mining
DS2003-0012
2003
Amarc Resources Ltd.Amarc Resources Ltd.Amarc terminates option on Fox RiverAmarc Res., Jan 10, 1/8p.ManitobaPress release, Falconbridge
DS1990-0116
1990
Amari, S.Amari, S., Anders, E., Virag, A.Interstellar graphite in meteoritesNature, Vol. 345, No. 6272, May 17, p. 238-239GlobalMeteorites, Graphite
DS1990-0928
1990
Amari, S.Lewis, R.S., Amari, S., Anders, E.Meteoritic silicon carbide: pristine material from carbon starsNature, Vol. 348, No. 6299, November 22, pp. 293-297GlobalMeteorites, Petrology
DS201012-0164
2010
Amarsaikhan, T.Dorjnamjaa, D., Selenge, D., Amarsaikhan, T., Enkhbaatar, B.Some new scientific facts on the diamond and gold forming astropipe geostructures of Mongolia.Goldschmidt 2010 abstracts, PosterAsia, MongoliaMeteorite
DS200712-0267
2007
Amarsaikhan, Ts.Dorijnamjaa, D., Kondratov, L.S., Voinkov, D.M., Amarsaikhan, Ts.Specific gas composition of the absorbed form in impatites of the diamond bearing Mongolian astropipes.Plates, Plumes, and Paradigms, 1p. abstract p. A231.Asia, MongoliaAgit Khangay, Khuree Mandal Tsenkher, Bayan Khuree
DS201012-0810
2010
Amaru, M.L.Van der Meer, D.G., Spakman, W., Van Hinsbergen, D.J.J., Amaru, M.L., Torsvik, T.H.Towards absolute plate motions constrained by lower mantle slab remnants.Nature Geoscience, Vol. 3, Jan. pp. 36-40.MantleTectonics, Pangea
DS1991-0019
1991
Amato, I.Amato, I.The high side of gravity. Crystals can grow bigger and betterScience, Vol. 253, July 5, pp. 30-32GlobalCrystallography, General morphology -not specific to diamonds
DS1991-0020
1991
Amato, I.Amato, I.Fanning the hope for flat diamondScience, Vol. 252, No. 5004, April 19, p. 375GlobalMineralogy, Diamond morphology
DS1991-0021
1991
Amato, I.Amato, I.GE achieves dial an isotope diamondScience, Vol. 254, November 1, p. 653GlobalNews item, Synthetic diamonds
DS201707-1315
2017
Amaud, N.Chmyz, L., Amaud, N., Biondi, J.C., Azzone, R.G., Bosch, D., Ruberti, E.Ar-Ar ages, Sr-Nd isotope geochemistry and implications for the origin of the silicate rocks of the Jacupiranga ultramafic alkaline complex, Brazil.Journal of South American Earth Sciences, Vol. 77, pp. 286-309.South America, Brazilalkaline - Jacupiringa

Abstract: The Jacupiranga Complex is one of several Meso-Cenozoic alkaline intrusive complexes along the margins of the intracratonic Paraná Basin in southern Brazil. The complex encompasses a wide range of rock-types, including dunites, wehrlites, clinopyroxenites, melteigites-ijolites, feldspar-bearing rocks (diorites, syenites, and monzonites), lamprophyres and apatite-rich carbonatites. While carbonatites have been extensively investigated over the last decades, little attention has been paid to the silicate rocks. This study presents new geochonological and geochemical data on the Jacupiranga Complex, with particular emphasis on the silicate lithotypes. 40Ar/39Ar ages for different lithotypes range from 133.7 ± 0.5 Ma to 131.4 ± 0.5 Ma, while monzonite zircon analyzed by SHRIMP yields a U-Pb concordia age of 134.9 ± 1.3 Ma. These ages indicate a narrow time frame for the Jacupiranga Complex emplacement, contemporaneous with the Paraná Magmatic Province. Most of the Jacupiranga rocks are SiO2-undersaturated, except for a quartz-normative monzonite. Based on geochemical compositions, the Jacupiranga silicate lithotypes may be separated into two magma-evolution trends: (1) a strongly silica-undersaturated series, comprising part of the clinopyroxenites and the ijolitic rocks, probably related to nephelinite melts and (2) a mildly silica-undersaturated series, related to basanite parental magmas and comprising the feldspar-bearing rocks, phonolites, lamprophyres, and part of the clinopyroxenites. Dunites and wehrlites are characterized by olivine compositionally restricted to the Fo83-84 interval and concentrations of CaO (0.13–0.54 wt%) and NiO (0.19–0.33 wt%) consistent with derivation by fractional crystallization, although it is not clear whether these rocks belong to the nephelinite or basanite series. Lamprophyre dikes within the complex are considered as good representatives of the basanite parental magma. Compositions of calculated melts in equilibrium with diopside cores from clinopyroxenites are quite similar to those of the lamprophyres, suggesting that at least a part of the clinopyroxenites is related to the basanite series. Some feldspar-bearing rocks (i.e. meladiorite and monzonite) show petrographic features and geochemical and isotope compositions indicative of crustal assimilation, although this may be relegated to a local process. Relatively high CaO/Al2O3 and La/Zr and low Ti/Eu ratios from the lamprophyres and calculated melts in equilibrium with cumulus clinopyroxene point to a lithospheric mantle metasomatized by CO2-rich fluids, suggesting vein-plus-wall-rock melting mechanisms. The chemical differences among those liquids are thought to reflect both variable contributions of melting resulting from veins and variable clinopyroxene/garnet proportions of the source.
DS1960-0727
1966
Amb, H.Paulitsch, P., Amb, H.Carbonatites, their Fabric, Chemistry and their GenesisIndia Mineralogical Society Volume, Edited By P.r.j. Naidu, Proceedings 4TH. GENERAL MEETING, PP. 140-147.IndiaRelated Rocks
DS1991-0022
1991
Ambroise, M.Ambroise, M.Geology of the northeast Angolan kimberlite regionProceedings of Fifth International Kimberlite Conference held Araxa June, pp. 6-9AngolaStructure -Lunda, Cassai Shield
DS201909-2080
2019
Ambrosia, F.Rosatelli, G., Ambrosia, F., Castorina, F., Stoppa, F., Schiazza, M.Mt. Vulture alkaline carbonatite ring complex reconstruction using holocrystalline ejecta.Goldschmidt2019, 1p. AbstractEurope, Italydeposit - Mt. Vulture

Abstract: The Mt. Vulture (Basilicata, Southern Italy) is an alkaline carbonatite volcano whose extrusive rocks are mafic, alkaline with different Na/K ratios, mainly SiO2 undersaturated, with relatively high contents of Cl, S, F, and CO2 [1]. Their composition ranges from basalts to basanites to tephrite to phono-tephrites and phonolites. Along with this magma suite have been erupted mantle xenolith bearing-carbonatitic melilitites and carbonatites [1, 2]. Holocrystalline ejecta have been studied in detail to reconstruct the composition of the subvolcanic/plutonic bodies beneath Mt. Vulture. The ejacta are haüine-bearing clinopyoxenites with variable content of olivine, amphibole and phlogopite, haüine foidolites with some nepheline and leucite, haüine-calcite-syenites, syenites, calcite melilitolites, K-feldspar bering-alvikites and a sovite [3]. There is a continuous variation in the modal and geochemical composition between clinopyroxenite and foidolite, that might be related to the chemical evolution shown by the extrusive rocks. The ejecta show an enrichment trend in LILE, LREE and HFSE consistent with fractional crystallisation evolution, from clinopyroxenites to foidolites and from foid-syenites to syenites. The foid-syeniites are rich in U, Pb, Sr, LREE and contain britholite, wholerite, Upyrochlore. The most evolved syenite however, is less enriched in REE but contains elevate content of U and HFSE. The sovite contains intercumulus alkali carbonates. A glimemerite vein in a haüine foidolite contain REE-rich apatite, shorlomite and U-pyrochlore. These findings suggest that alkaline-alogen-H2O-CO2 rich fluids can be formed during sub-volcanic/plutonic fractional crystallisation. These fluids can produce fenitisation and/or can form mineralisation enriched in REE and HFSE. The ejecta suite studied represents the intrusive complex beneath the volcano and these rock types are typical of ring complexes in alkaline carbonatite volcanoes.
DS201909-2092
2019
Ambrosio, A.Stoppa, F., Schiazza, M., Rosatelli, G., Castorina, F., Sharygin, V.V., Ambrosio, A., Vicentini, N.Italian carbonatite system: from mantle to ore deposit.Ore Geology Reviews, in press available, 59p. PdfEurope, Italycarbonatite

Abstract: A new discovery of carbonatites at Pianciano, Ficoreto and Forcinelle in the Roman Region demonstrates that Italian carbonatites are not just isolated, mantle xenoliths-bearing, primitive diatremic rocks but also evolved sub-type fluor-calciocarbonatite (F?10 wt.%) associated with fluor ore (F?30 wt.%). New data constrain a multi-stage petrogenetic process, 1-orthomagmatic, 2-carbothermal, 3-hydrothermal. Petrography and geochemistry are conducive to processes of immiscibility and decarbonation, rather than assimilation and crystal fractionation. A CO2-rich, ultra-alkaline magma is inferred to produce immiscible melilite leucitite and carbonatite melts, at lithospheric mantle depths. At the crustal level and in the presence of massive CO2 exsolution, decarbonation reactions may be the dominant processes. Decarbonation consumes dolomite and produces calcite and periclase, which, in turn, react with silica to produce forsterite and Ca silicates (monticellite, melilite, andradite). Under carbothermal conditions, carbonate breakdown releases Sr, Ba and LREE; F and S become concentrated in residual fluids, allowing precipitation of fluorite and barite, as well as celestine and anhydrite. Fluor-calciocarbonatite is the best candidate to exsolve fluids able to deposit fluor ore, which has a smaller volume. At the hydrothermal stage, REE concentration and temperature dropping allow the formation of LREEF2+ and LREECO3+ ligands, which control the precipitation of interstitial LREE fluorcarbonate and silicates -(bastnäsite-(Ce)- Ce(CO3)F and -britholite-(Ce)- (Ce,Ca)5(SiO4,PO4)3(OH,F) . Vanadates such as wakefieldite, CeVO4, vanadinite, Pb5(VO4)3Cl and coronadite Pb(Mn4+6 Mn3+2)O16 characterise the matrix. At temperatures of ?100°C analcime, halloysite, quartz, barren calcite, and zeolites (K-Ca) precipitate in expansion fractures, veins and dyke aureoles.
DS201911-2566
2019
Ambrosio, F.A.Stoppa, F., Schiazza, M., Rosatelli, G., Castorina, F., Sharygin, V.V., Ambrosio, F.A., Vicentini, N.Italian carbonatite system: from mantle to ore deposit.Ore Geology Reviews, Vol. 114, 17p. PdfEurope, Italycarbonatite

Abstract: A new discovery of carbonatites at Pianciano, Ficoreto and Forcinelle in the Roman Region demonstrates that Italian carbonatites are not just isolated, mantle xenoliths-bearing, primitive diatremic rocks but also evolved sub-type fluor-calciocarbonatite (F~10 wt.%) associated with fluor ore (F~30 wt.%). New data constrain a multi-stage petrogenetic process, 1-orthomagmatic, 2-carbothermal, 3-hydrothermal. Petrography and geochemistry are conducive to processes of immiscibility and decarbonation, rather than assimilation and crystal fractionation. A CO2-rich, ultra-alkaline magma is inferred to produce immiscible melilite leucitite and carbonatite melts, at lithospheric mantle depths. At the crustal level and in the presence of massive CO2 exsolution, decarbonation reactions may be the dominant processes. Decarbonation consumes dolomite and produces calcite and periclase, which, in turn, react with silica to produce forsterite and Ca silicates (monticellite, melilite, andradite). Under carbothermal conditions, carbonate breakdown releases Sr, Ba and LREE; F and S become concentrated in residual fluids, allowing precipitation of fluorite and barite, as well as celestine and anhydrite. Fluor-calciocarbonatite is the best candidate to exsolve fluids able to deposit fluor ore, which has a smaller volume. At the hydrothermal stage, REE concentration and temperature dropping allow the formation of LREEF2+ and LREECO3+ ligands, which control the precipitation of interstitial LREE fluorcarbonate and silicates -(bastnäsite-(Ce)- Ce(CO3)F and -britholite-(Ce)- (Ce,Ca)5(SiO4,PO4)3(OH,F) . Vanadates such as wakefieldite, CeVO4, vanadinite, Pb5(VO4)3Cl and coronadite Pb(Mn4+6 Mn3+2)O16 characterise the matrix. At temperatures of =100°C analcime, halloysite, quartz, barren calcite, and zeolites (K-Ca) precipitate in expansion fractures, veins and dyke aureoles.
DS1992-0297
1992
Ambroziak, R.A.Cook, C.A., Ambroziak, R.A.Demonstration disk for United States Geological Survey (USGS)-OEMG mapping softwareUnited States Geological Survey (USGS) Open File, No. 92-0691, 3p. $ 6.50GlobalComputer, Program -United States Geological Survey (USGS)-OEMG
DS1993-0028
1993
Ambroziak, R.A.Ambroziak, R.A., Cook, C.A., Woodwell, G.R., Wicks, R.E.Computer mapping at your desk that really works.Geological Society of America short course, 50pGlobalBook -table of contents, Computer, mapping
DS1993-1235
1993
Ambroziak, R.A.Phillips, J.D., Duval, J.S., Ambroziak, R.A.National geophysical dat a and topographic dat a for the conterminous USAUnited States Geological Survey (USGS), DDS-0009, 1 disc. $ 32.00United StatesGeophysics, CD-ROM datafile
DS1994-0042
1994
Ambroziak, R.A.Ambroziak, R.A., Cook, C.A., Goowell, G.R., Dargusch, T.Computer mapping at your desk .. that really works.. short course aboutcreating digital maps on a PC.Geological Society of America (GSA) Short Course, 100p. approx. $ 15.00GlobalBook -table of contents, Computer mapping programs
DS1994-0907
1994
Amclung, F.King, G., Oppenheimer, D., Amclung, F.Block versus continuum deformation in the Western United StatesEarth Planet. Sci. Letters, Vol. 128, No. 3-4, Dec. pp. 55-64United States, Cordillera, NevadaTectonics
DS200712-0013
2005
AMEBc and PDACAMEBc and PDACCanadian Mineral Exploration Health & Safety annual report,AMEBC, PDAC, Sept. 2006, 52p.CanadaHealth, safety statistics
DS1992-0019
1992
Amelin, J.V.Amelin, J.V., Semenov, V.S.Enriched and depleted components in early Proterozoic mantle: evidence from neodymium and Sr isotopic study of layered intrusions and mafic dykes eastern shieldEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.338Russia, eastern shieldMantle, Dykes, Geochronology
DS1994-0346
1994
Amelin, Y.Corriveau, L., Amelin, Y., Gorton, M.P., Morin, D.Geochemical constraints on Proterozoic potassium-rich alkaline and shoshonitic magmas evolution in the S.W. Grenville Province.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.OntarioAlkaline rocks, Shoshonite
DS1996-0300
1996
Amelin, Y.Corriveau, L., Morin, D., Tellier, M., Amelin, Y., et al.Insights on minette emplacement and lithosphere underlying the southwest Grenville Province at 1, 08 Ga.Geological Survey of Canada, LeCheminant ed, OF 3228, pp. 139-142.QuebecMinettes, Geochronology
DS1996-0301
1996
Amelin, Y.Corriveau, L., Tellier, M., Dorin, D., Amelin, Y.Le dyke de minette de Rivard et le complexe gneissique cuprifrer de Bondy:implications tectoniques....Geological Survey of Canada (GSC) Open File, No. 3078, 73p.Quebec, GrenvilleMinettes
DS1999-0010
1999
Amelin, Y.Amelin, Y.Nature of the Earth's earliest crust from hafnium isotopes in single detrital zircon.Nature, Vol. 399, No. 6733, May 20, pp. 252-4.MantleGeochronology
DS2000-0017
2000
Amelin, Y.Amelin, Y., Lee, D.C., Halliday, A.N.Early middle Archean crustal evolution deduced from Lutetium - Hafnium and uranium-lead (U-Pb) isotopic studies.Geochimica et Cosmochimica Acta, Vol. 64, No. 24, Dec. 1, pp. 4205-26.MantleTectonics, Geochronology
DS200512-0217
2005
Amelin, Y.Davis, D.W., Amelin, Y., Nowell, G.M., Parrish, R.R.Hf isotopes in zircon from western Superior province, Canada: implications for Archean crustal development and evolution of the depleted mantle reservoir.Precambrian Research, in pressCanada, Ontario, ManitobaGeochronology
DS200612-0015
2006
Amelin, Y.Amelin, Y.A tale of early Earth told in zircons.Science, Vol. 310, 5756, Dec. 23, pp. 1914-1915.MantleGeochronology
DS201312-0015
2013
Amelin, Y.Amelin, Y., Ireland, T.R.Dating the oldest rocks and minerals in the Solar system.Elements, Vol. 9, pp. 39-44.TechnologyGeochronology - meteorites
DS201512-1962
2015
Amelin, Y.Rukhov, A.S., Bell, K., Amelin, Y.Carbonatites, isotopes and evolution of continental mantle: an overview.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 39-64.MantleCarbonatite
DS201604-0624
2016
Amelin, Y.Rukhhlov, A.S., Bell, K., Amelin, Y.Carbonatites, isotopes and evolution of the subcontinental mantle: an overview.GAC MAC Meeting Special Session SS11: Cratons, kimberlites and diamonds., abstract 1/4p.MantleCarbonatite
DS201909-2098
2019
Amelin, Y.Timmerman, S., Honda, M., Burnham, A.D., Amelin, Y., Woodland, S., Pearson, D.G., Jaques, A.L., Le Losq, C., Bennett, V.C., Bulanova, G.P., Smith, C.B., Harris, J.W., Tohver, E.Primordial and recycled helium isotope signatures in the mantle transition zone. Science, Vol. 365, 6454, pp. 692-694.Mantlediamond genesis

Abstract: Isotope compositions of basalts provide information about the chemical reservoirs in Earth’s interior and play a critical role in defining models of Earth’s structure. However, the helium isotope signature of the mantle below depths of a few hundred kilometers has been difficult to measure directly. This information is a vital baseline for understanding helium isotopes in erupted basalts. We measured He-Sr-Pb isotope ratios in superdeep diamond fluid inclusions from the transition zone (depth of 410 to 660 kilometers) unaffected by degassing and shallow crustal contamination. We found extreme He-C-Pb-Sr isotope variability, with high 3He/4He ratios related to higher helium concentrations. This indicates that a less degassed, high-3He/4He deep mantle source infiltrates the transition zone, where it interacts with recycled material, creating the diverse compositions recorded in ocean island basalts.
DS1998-0024
1998
Amelin, Y.V.Amelin, Y.V., Neymark, L.A.Lead isotope geochemistry of Paleoproterozoic layered intrusions in the eastern Baltic Shield: magma sourcesGeochimica et Cosmochimica Acta, Vol. 62, No. 3, Feb. pp. 493-505.Baltic Shield, Karelia, KolaOlanga complex, Crust-mantle system
DS1995-0030
1995
Amelin, Yu.V.Amelin, Yu.V., Heaman, L.M., Semenov, V.S.Uranium-lead (U-Pb) geochronology of layered mafic intrusions in the eastern BalticShield: implications for timing and duration..Precambrian Research, Vol. 75, pp. 31-46.Russia, Baltic States, Kola PeninsulaGeochronology, Pechenga, nickel, platinum group elements (PGE), Ultramafic intrusions
DS200812-0738
2008
AmelioMelluso, L., Lustrino, M., Ruberti, E., Brotzu, P., Barros Gomes, C., Morbidelli, Morra, Svisero, AmelioMajor and trace element composition of olivine perovskite, clinopyroxene, Cr Fe Ti oxides, phlogopite and host kamafugites and kimberlites, Alto Paranaiba,Canadian Mineralogist, Vol. 46, no. 2 Feb. pp. 19-40.South America, BrazilKamafugite, kimberlite
DS200912-0053
2009
Amelung, F.Biggs, J., Amelung, F., Gourmelen, N., Dixon, T.H.,Kim, S-W.InSAR observations of 2007 Tanzania rifting episode reveal mixed fault and dyke extension in an immature continental rift.Geophysical Journal International, Vol. 179, 1, pp. 549-558.Africa, TanzaniaGeophysics - seismics
DS2001-0246
2001
AmennaDerder, M.E.M., Henry, B., Merabet, N., Amenna, BouroisUpper Carboniferous paleomagnetic pole from the stable Saharan Craton and Gondwana reconstructions.Journal of African Earth Science, Vol. 32, No. 3, Apr. pp. 491-502.South AfricaGeophysics - paleomagnetism, Gondwanaland
DS2002-0123
2002
AmennaBayou, B., Derder, M.E., Henry, B., Djellit, H.,AmennaPremier pole paleomagnetique d'age Mosvien constraint par un test du pli, obtenu dans le bassin d'Illizi.Comptes Rendus Geosciences, Vol.334,2,pp. 81-7.AlgeriaCraton - Sahara, Paleomagnetism
DS1992-0020
1992
Amenta, R.V.Amenta, R.V., Cooper, J.M., Bunting, R., Romeo, C.Simulating fabric development in igneous rocks: a solution for modeling space competition among growing crystalsComputers and Geosciences, Vol. 18, No. 6, pp. 763-766GlobalComputers, Igneous rocks -crystallography
DS1860-0648
1890
American AnalystAmerican AnalystDiamonds; American Analyst, 1890American Analyst., Vol. 6, JUNE 5TH. P. 269.GlobalDiamond Genesis
DS1860-0687
1891
American AnalystAmerican AnalystStellar Diamonds. a Suggestion As to the Meteorite Origin Of the Diamond. Canon DiableAmerican Analyst., Vol. 7, No. 39, SEPT. 24TH. P. 462.South Africa, United States, Arizona, Colorado PlateauDiamond Genesis
DS1995-0031
1995
American Association Petrol. GeolAmerican Association Petrol. GeolTectonic map of the worldAmerican Association of Petroleum Geologists, 1: 10, 000, 000 please note price $ 1, 000.00GlobalMap -tectonic, Map -ad
DS1900-0465
1907
American Diamond CompanyAmerican Diamond CompanyProspectus Adc 1907Texarkana: American Diamond Company, 8P. 1 MAP.United States, Gulf Coast, Arkansas, PennsylvaniaEconomics
DS1860-0584
1888
American EngineeringAmerican EngineeringDiamonds in Clayton County, GeorgiaAmerican Engineering, Vol. 16, No. 8, JULY 4TH.United States, GeorgiaDiamond Occurrence
DS1900-0168
1903
American ExporterAmerican ExporterScientists Theory of American Diamond FieldsAmerican EXPORTER., Vol. 51, No. 4, MARCH P. 24.United StatesDiamond Occurrence
DS1900-0173
1903
American ExporterAmerican ExporterDiamonds Found in OregonAmerican EXPORTER., Vol. 51, No. 4, MARCH P. 24.United States, Oregon, Rocky MountainsDiamond Occurrence
DS1930-0266
1938
American Gem SocietyAmerican Gem SocietyDiamonds, Their Purchase and Care. Authentic Facts Regarding Mining, Cutting and Qualities Which Affect Their Value.Los Angeles: American Gem Society, 32P.GlobalKimberlite, Kimberley, Pamphlet
DS1900-0514
1907
American Geographical SocietyAmerican Geographical SocietyDiamonds in Place in the United StatesAmerican GEOGRAPH. SOC. Bulletin., Vol. 39, PP. 742-743.United States, Gulf Coast, ArkansasDiamond Occurrence
DS1992-0021
1992
American Geological InstituteAmerican Geological InstitutePlanning for field safetyAmerican Geological Institute, 197p. $ 19.95 United StatesGlobalField Safety, Book -ad
DS1992-0022
1992
American Geological InstituteAmerican Geological InstituteGeoscience theses of the United States and CanadaAmerican Geological Institute Bibliography of Geoscience Theses, $ 425.00 United StatesUnited States, CanadaBibliography, Book -ad
DS1995-0032
1995
American geological InstituteAmerican geological InstituteUnion list of field trip guidebooks of North AmericaAmerican Geological Institute, 6th. edition, $ 80.00 United StatesNorth AmericaGuidebook list, Book -ad
DS1996-0021
1996
American Geological InstituteAmerican Geological InstituteUnion list of geologic field trip guidebooks of North AmericaAmerican Geological Institute, Canada, United StatesBook -ad, Guidebook listing
DS1996-0022
1996
American Geological InstituteAmerican Geological InstituteGroundwater and soil contamination databaseAmerican Geological Institute, GlobalEnvironmental database -groundwater, soil, CD-ROM ad
DS1998-0025
1998
American geological InstituteAmerican geological InstituteMineral resources of Russia: economics and managementAmerican Geological Institute, $ 110.00 United StatesRussiaJournal - ad, Economics, management, legal, resources
DS1860-0690
1891
American GeologistAmerican GeologistDiamond in Wisconsin. #1American Geologist, Vol. 7, Jan. P. 72.United States, Wisconsin, AppalachiaDiamond Occurrence
DS2001-0022
2001
American IDC.American IDC.American IDC to acquire prime South African diamond mining operation. Lovedale, Holsdam, GoedgedachtAmerican IDC., June 21, 3p.South AfricaNews item - press release, Whiterock Holdings Ltd.
DS1860-0020
1866
American Journal of MiningAmerican Journal of MiningDiamonds at CherokeeAmerican Journal of Mining, Vol. 1, JULY 7TH. P. 226.United States, California, West CoastDiamond Occurrence
DS1860-0021
1866
American Journal of MiningAmerican Journal of MiningDiamonds in Butte CountyAmerican Journal of Mining, Vol. 1, MAY 19TH. P. 125.United States, California, West Coast, MontanaDiamond Occurrence
DS1860-0023
1866
American Journal of MiningAmerican Journal of MiningDiamonds in the Southern StatesAmerican Journal of Mining, Vol. 1, JULY 7TH. PP. 227-228.United States, Georgia, AppalachiaDiamond Occurrence
DS1860-0040
1867
American Journal of MiningAmerican Journal of MiningDiamonds in California, 1867American Journal of Mining, Vol. 3, JUNE 22ND. P. 251.United States, California, West CoastDiamond Occurrence
DS1860-0042
1867
American Journal of MiningAmerican Journal of MiningDiamonds in Amador CountyAmerican Journal of Mining, Vol. 4, SEPT. 28TH. P. 202.United States, California, West Coast, AmadorDiamond Occurrence
DS1860-0043
1867
American Journal of MiningAmerican Journal of MiningDiamonds in the United StatesAmerican Journal of Mining, Vol. 4, SEPT. 7TH. PP. 145-146.United States, California, West Coast, Idaho, Virginia, Georgia, North CarolinaDiamond Occurrence
DS1860-0044
1867
American Journal of MiningAmerican Journal of MiningPrecious Stone in GeorgiaAmerican Journal of Mining, Vol. 3, MAY 11TH. P. 122.United States, Georgia, AppalachiaDiamond Occurrence
DS1860-0045
1867
American Journal of MiningAmerican Journal of MiningDiamonds in Idaho, 1867American Journal of Mining, Vol. 4, SEPT. 7TH. PP. 145-146.United States, Idaho, Rocky MountainsDiamond Occurrence
DS1859-0083
1846
American Journal of ScienceAmerican Journal of ScienceDiamonds in North Carolina. Diamonds in the UralsAmerican Journal of Science, 2ND. SER. Vol. 2, NOVEMBER P. 119-120.United States, Appalachia, North Carolina, RussiaDiamond Occurrences
DS1860-0127
1871
American Journal of ScienceAmerican Journal of ScienceDiamond Export from the Cape ColonyAmerican Journal of Science, SER. 1, Vol. 59, P. 306.Africa, South Africa, Cape ProvinceHistory, production
DS1859-0048
1835
American MagazineAmerican MagazineDiamond Found in North CarolinaAmerican Magazine, Vol. 2, DECEMBER P. 139.United States, North Carolina, AppalachiaDiamond Occurrence
DS1900-0103
1902
American MiningAmerican MiningFinds a Diamond Field. Gems of First Water Discovered in Montana.American Mining News, Vol. 6, No. 139, Jan. 25TH. P. 1.United States, Montana, Rocky Mountains, FergusDiamond Occurrence
DS1900-0169
1903
American MiningAmerican MiningDiamonds in California, 1903American Mining , Vol. 7, No. 198, MARCH 14TH. P. 7.United States, California, West CoastDiamond Occurrence
DS201412-0684
2015
Ames, D.E.Petrus, J.A., Ames, D.E., Kamber, B.S.On the track of the elusive Sudbury impact: geochemical evidence for a chondrite or comet bolide.Terra Nova, Vol. 27, pp. 9-20.Canada, OntarioMeteorite
DS201502-0090
2015
Ames, D.E.Petrus, J.A., Ames, D.E., Kamber, B.S.On the track of the elusive Sudbury impact: geochemical evidence for a chondrite or comet bolide.Terra Nova, Vol. 27, 1, pp. 9-20.Canada, OntarioMeteorite
DS201706-1073
2017
Ames, D.E.Good, D.J., Cabri, L.J., Ames, D.E.PGM facies variations for Cu-PGE deposits in the Coldwell alkaline complex, Ontario, Canada.Ore Geology Reviews, in press available 36p.Canada, Ontarioalkaline rocks

Abstract: Accurate characterization of the platinum group mineral (PGM) assemblages for Cu-Ni-PGE deposits are typically constrained by sample size and the difficulty of finding statistically significant numbers of grains, which is expected given the low concentrations of platinum group elements (<2 ppm), the great variety of PGM, and the likelihood that a few large grains (>75 µm) can account for large fractions of total mass. Despite these limitations, an accurate survey of PGM from different deposit types would have significant value towards developing deposit models and respective exploration strategies. In this study, we present results for a comprehensive evaluation of PGM at four copper-PGE occurrences hosted within separate but co-genetic gabbro or troctolite intrusions in the Coldwell Alkaline Complex and confirm that accurate surveys are possible with sufficient sample material and efficient PGM concentration methods. The PGM concentration methods used include: (1) hydroseparation of sieved size fractions of pulverized material, and (2) panning of grain separates produced by electric pulse disaggregation of drill core specimens. A favourable comparison of the results has verified the reliability of each method and added confidence that the PGM assemblages identified at three of the four locations are fully characterized. Precious metal mineral (PMM) assemblages are determined for the Main zone and W Horizon at the Marathon deposit, and the main zones at each of the Geordie Lake deposit and Area 41 occurrence. A total of 10,824 PMM grains (PGE and Au-Ag) and 68 mineral species, including 16 unknown minerals, were identified, of which 768 grains and 31 species occur at the Main zone, 523 grains and 41 species at Area 41,9485 grains and 43 species at W horizon, and 56 grains and 12 species at Geordie Lake. The PMM are grouped as follows: Pd-Ge, PGE-S-As, Pt-Fe alloy, Pd-Cu-Pb-Au, Pd-Ni-S, Pd-Pt-Sn, Pt-As, Pd-As, Pd-Pt-Sb-As, Pd-Pt-Bi-Te, and Au-Ag. All of the deposits were found to contain similar proportions of Pd-Pt-Sb-As, Pd-Pt-Bi-Te and Au-Ag minerals. But the W Horizon and Area 41 are distinguished from the Marathon Main zone and Geordie Lake deposits by the presence of minerals in the PGE-S-As, Pt-Fe alloy, Pd ± Cu ± Pb ± Au and Pd-Ge groups. Taken together, the PMM assemblages for deposits in the Coldwell exhibit a strong correlation to PGE enrichment relative to the range for mantle Cu/Pd values (1000-10,000). And there is no relationship between the abundances of Pd-Pt-Bi-Te and Pd-Pt-Sb-As minerals that are commonly associated with hydrous phases, and the intensity of hydrothermal alteration. Thus minerals found only at the W Horizon and Area 41, where significant PGE upgrading has occurred, including Pt-Fe alloys, rustenburgite, marathonite, palladogermanide, unknown Rh-Ni-Fe-sulfide, Au-Pd-Cu alloy, braggite, coldwellite, laurite, zvyagintsevite, laflammeite, and unknown phases Pd5As2, Pd3As, Pd3(As,Pb,Bi) might be considered as index minerals for PGE enriched types of mineralization in the Coldwell.
DS201707-1303
2017
Ames, D.E.Ames, D.E., Kjarsgaard, I.M., McDonald, A.M., Good, D.J.Insights into the extreme PGE enrichment of the W Horizon, Marathon Cu-Pd deposit, Coldwell alkaline complex, Canada: platinum group mineralogy, compositions and genetic implications.Ore Geology Reviews, in press availableCanada, Ontarioalkaline - Coldwell Complex

Abstract: The W Horizon, Marathon Cu-Pd deposit in the Mesoproterozoic Midcontinent rift is one of the highest grade PGE repositories in magmatic ore deposits world-wide. The textural relationships and compositions of diverse platinum-group mineral (PGM) and sulfide assemblages in the extremely enriched ores (>100 ppm Pd-Pt-Au over 2 m) of the W Horizon have been investigated in mineral concentrates with ?10,000 PGM grains and in situ using scanning electron microprobe and microprobe analyses. Here we show, from ore samples with concentrations up to 23.1 Pd ppm, 8.9 Pt ppm, 1.4 Au ppm and 0.73 Rh ppm, the diversity of minerals (n = 52) including several significant unknown minerals and three new mineral species marathonite (Pd25Ge9; McDonald et al., 2016), palladogermanide (Pd2Ge; IMA 2016-086, McDonald et al., 2017), kravtsovite (PdAg2S, IMA No 2016-092, Vymazalová et al., 2017). The PGM are distributed as PG-, sulfides (52 vol%), -arsenides (34 vol%), -intermetallics of Au-Ag-Pd-Cu and Pd-Ge(10 vol%) and -bismuthides and tellurides (4 vol%). The discovery of abundant (>330 grains) large unknown sulfide minerals with Rh allows us to present analyses three significant potentially new minerals (WUK-1, WUK-2, WUK-3) that are all clearly enriched in Rh (averaging 4.2, 8.5 and 28.21 wt% Rh respectively). Several examples of paragenetic sequences and mineral chemical changes for enrichment of Cu, Pd and Rh with time are revealed in the PGM and base-metal sulfides. We suggest this enhanced metal enrichment formed in response to increasing fO2 causing the oxidation of Fe2+ to Fe3+ and to a lesser extent, S. Phase relations in the Ag-Pd-S, Rh-Ni-Fe-S, Pd-Ge, Au-Pd-Cu-Ag, Pd-Ag-Te systems help constrain the crystallization temperatures of the majority of ore minerals in the W Horizon at ?500 °C or moderate to high subsolidus temperatures (400–600 °C). Local transport by aqueous fluids becomes evident as minerals recrystallize down to <300 °C. The PGE-enriched W Horizon ores exhibit a complex post-magmatic history dominated by the effects of oxidation during cooling of a Cu-PGE enriched magma source from a deep reservoir.
DS1993-0029
1993
Ames, L.Ames, L., Tilton, G.R., Zhou, G.Timing of collision of the Sino-Korean and Yangtse cratons: uranium-lead (U-Pb) (U-Pb) zircon dating of coesite-bearing eclogitesGeology, Vol. 21, No. 4, April pp. 339-342ChinaDabie Mountains, Diamonds
DS1996-0023
1996
Ames, L.Ames, L., Zhou, XiongGeochronology and isotopic character of ultrahigh pressure metamorphism with implications for collision of the Sino Korean and Yangtze Cratons, centralChina.Tectonics, Vol. 15, No. 2, Apr. pp. 472-89.Chinametamorphism
DS1900-0225
1904
Ami, H.M.Ami, H.M.Search for Diamonds 1904G.s.c. Note., Canada, Great Lakes, OntarioProspecting
DS1900-0364
1906
Ami, H.M.Ami, H.M.Diamonds in Canada; April, 1906Winnipeg: Can. Inter. Ocean., Vol. 1, No. 1, APRIL P. 6.Canada, OntarioDiamond Occurrence
DS201412-0007
2014
Ami, S.Ami, S.Second -hand, like new. Recycled diamonds.Hayashalom Magazine, No. 215, pp. 34-37.TechnologyRecycled diamonds
DS1930-0193
1935
Amick, H.C.Hall, G.M., Amick, H.C.Mica Peridotite in TennesseeAmerican Mineralogist., Vol. 20, No. 3, PP. 204-205.United States, Appalachia, TennesseeRelated Rocks, Geology
DS1940-0085
1944
Amick, H.C.Hall, G.M., Amick, H.C.Igneous Rock Regions in the Norris RegionJournal of GEOLOGY, Vol. 52, PP. 424-430.United States, Appalachia, TennesseeRelated Rocks, Geology
DS1970-0004
1970
Aminco Association Pty LtdAminco Association Pty LtdFinal Report E.l. 228, WalchaNew South Wales Geological Survey Report., GS 1970/345, (UNPUBL.).Australia, New South WalesDiamond Prospecting
DS1981-0259
1981
Amini, M.H.Larson, E.E., Amini, M.H.Fission Track Dating of the Green Mountain Kimberlite Diatreme Near Boulder Colorado.The Mountain Geologist., Vol. 18, No. 1, PP. 19-22.ColoradoKimberlite, Rocky Mountains
DS201712-2671
2017
AmiraAmiraAmira Roadmap. Excellent documentation of their 15 year extensive compilation.amirainternational.com, amirainternational .com /WEB/sites/ P1162A/ Documents/ FinalDocuments/ Roadmap Documents Index.aspAustraliamineral project analyses
DS1982-0011
1982
Amirzhanov, A.A.Amirzhanov, A.A., Vorontsov, A.E., Plakhova, G.S.The Nature of Globular Alkali Basaltoids from Diatremes of The Southern Siberian PlatformDoklady Academy of Sciences AKAD. NAUK SSSR., Vol. 264, No. 6, PP. 1472-1477.RussiaBlank
DS1983-0622
1983
Amirzhanov, A.A.Vorontsov, A.YE., Amirzhanov, A.A., et al.Intergrowths of clinopyroxene- picroilmenite in a diatreme in southern Siberian Platform*(in Russian)Izv. Akad. Nauk SSSR Ser. Geol., (Russian), No. 8, pp. 29-34RussiaBlank
DS200712-0575
2007
Amirzhanov, A.A.Kostrovitsky, S.I., Morikyo, T., Serov, I.V., Yakovlev, D.A., Amirzhanov, A.A.Isotope geochemical systematics of kimberlites and related rocks from the Siberian Platform.Russian Geology and Geophysics, Vol. 48, pp. 272-290.RussiaGeochronology
DS200612-0016
2006
Amit, H.Amit, H., Olson, P.Time average and time dependent parts of core flow.Physics of the Earth and Planetary Interiors, In pressMantleTomography, geomagnetics, geodynamics
DS200812-0026
2008
Amit, H.Amit, H., Aubert, J., Hulot, G., Oldon, P.A simple model for mantle driven flow at the top of Earth's core.Earth Planets and Space, Vol. 60, 8, pp. 845-854.MantleTectonics
DS201012-0006
2010
Amit, H.Amit, H., Aubert, J., Hulot, G.Stationary, oscillating or drifting mantle driven geomagnetic flux patches?Journal of Geophysical Research, Vol. 115, B7, B7108.MantleGeophysics - magnetics
DS201112-0320
2011
Amit, H.Finlay, C.C., Amit, H.On flow magnitude and field flow alignment at Earth's core surface.Geophysical Journal International, In press available,MantleGeophysics - magnetics
DS201503-0132
2015
Amit, H.Amit, H., Olson, P.Lower mantle superplume growth excites geomagnetic reversals.Earth and Planetary Science Letters, Vol. 414, March 15, pp. 68-76.MantleHotspots

Abstract: Seismic images of the lower mantle reveal two large-scale, low shear wave velocity provinces beneath Africa and the Pacific that are variously interpreted as superplumes, plume clusters or piles of dense mantle material associated with the layer. Here we show that time variations in the height of these structures produce variations in heat flux across the core–mantle boundary that can control the rate at which geomagnetic polarity reversals occur. Superplume growth increases the mean core–mantle boundary heat flux and its lateral heterogeneity, thereby stimulating polarity reversals, whereas superplume collapse decreases the mean core–mantle boundary heat flux and its lateral heterogeneity, inhibiting polarity reversals. Our results suggest that the long, stable polarity geomagnetic superchrons such as occurred in the Cretaceous, Permian, and earlier in the geologic record were initiated and terminated by the collapse and growth of lower mantle superplumes, respectively.
DS1984-0569
1984
Amita, F.Osugi, S., Arase, T., Hara, K., Amita, F.Diamond Formation in Molten Nickel. (research Note)High Temperatures-high Pressures, Vol. 16, No. 2, PP. 191-195.GlobalExperimental Petrology
DS1930-0257
1937
Amm, F.L.Macgregor, A.M., Ferguson, J.C., Amm, F.L.The Geology of the Country Around the Queen's Mine, BulawayoGeological Survey Southern Rhodesia Bulletin., No. 30, 175P.ZimbabweColussus, Wessels, Geology
DS200912-0076
2009
Amman, M.Brodholt, J., Amman, M., Hunt, S., Walker, S., Dobson, D.The rheological properties of post-perovskite and implications for D'.Goldschmidt Conference 2009, p. A162 Abstract.MantleBoundary
DS201212-0165
2012
Ammann, M.Dobson, D., Ammann, M., Tackley, P.The grain size of the lower mantle.emc2012 @ uni-frankfurt.de, 1p. AbstractMantleConvection
DS201312-0946
2013
Ammann, M.W.Walker, A.M., Ammann, M.W., Stackhouse, S., Wookey, J., Bordholdt, J.P., Dobson, D.Anisotropy: a cause of heat flux variation at the CMB?Goldschmidt 2013, 1p. AbstractMantlePerovskite
DS201312-0016
2013
Ammannati, E.Ammannati, E.The role of carbon dioxide from recycled sediments in the genesis of ultrapotassic magmas from lithospheric mantle.Goldschmidt 2013, AbstractMantleMagmatism
DS201312-0017
2013
Ammannati, E.Ammannati, E., Foley, S.F., Avanzinelli, R., Jacob, D.E., Conticelli, S.Trace elements in olivine characterize the mantle source of subduction related potassic magmas.Goldschmidt 2013, AbstractMantleSubduction
DS1975-0907
1979
Ammerman, M.L.Ammerman, M.L., Keller, G.R.Delineation of Rome Trough in Eastern Kentucky with Gravity and Deep Drilling Data.American Association of Petroleum Geologists Bulletin., Vol. 63, PP. 341-353.GlobalMid-continent
DS1995-2118
1995
Ammon, C.J.Zandt, G., Ammon, C.J.Continental crust composition constrained by measurements of crustalPoisson's ratio.Nature, Vol. 374, No. 6518, March 9, pp. 152-153.MantleCrust composition
DS200512-0488
2005
Ammon, C.J.Jordi, J., Ammon, C.J., Nyblade, A.A.Evidence for mafic lower crust in Tanzania, East Africa, from joint inversion of receiver functions and Rayleigh wave dispersion velocities.Geophysical Journal International, Vol. 162, 2, August pp.555-569.Africa, TanzaniaGeophysics - seismics
DS201212-0014
2012
Amodeo, J.Amodeo, J., Carrez, Ph., Cordier, P., Gouriet, K., Kraych, A.Modelling dislocation and plasticity in MgO and MgSiO3 perovskite under lower mantle conditions.emc2012 @ uni-frankfurt.de, 1p. AbstractMantlePerovskite
DS201212-0132
2012
Amodeo, J.Cordier, P., Amodeo, J., Carrez, P.Modelling the rheology of MgO under Earth's mantle pressure, temperature and strain rates.Nature, Vol. 481, Jan. 12, pp. 177-180.MantleRheology
DS1999-0771
1999
Amor, J.R.Viejo, G.F., Clowes, R.M., Amor, J.R.Imaging the lithospheric mantle in northwestern Canada with seismic wide angle reflections.Geophysical Research. Lett., Vol. 26, No. 18, Sept. 15, pp. 2809-12.Saskatchewan, Manitoba, Alberta, Northwest TerritoriesGeophysics - seismics, Lithosphere
DS201702-0210
2017
Amor, M.Deibe, D., Amor, M., Doallo, R., Miranda, M., Cordero, M.GVLiDAR: an interactive web-based visualization frameowrk to support geospatial measures on lidar data.International Journal of Remote Sensing, Vol. 38, 3, pp. 827-849.TechnologyLIDAR

Abstract: In recent years lidar technology has experienced a noticeable increase in its relevance and usage in a number of scientific fields. Therefore, software capable of handling lidar data becomes a key point in those fields. In this article, we present GPU-based viewer lidar (GVLiDAR), a novel web framework for visualization and geospatial measurement of lidar data point sets. The design of the framework is focused on achieving three key objectives: performance in terms of real-time interaction, functionality, and online availability for the lidar datasets. All lidar files are pre-processed and stored in a lossless data structure, which minimizes transfer requirements and offers an on-demand lidar data web framework.
DS1998-0026
1998
Amor, S.Amor, S., Bloom, L.Practical application of exploration geochemistryPros. Developers Assoc, Short course approx. 200pGlobalBook - table of contents, Geochemistry - technology
DS1970-0005
1970
Amos, D.H.Amos, D.H., Desborough, G.A.Mafic Intrusive Rocks of Precambrian Age in Southeast Missouri #2Missouri Bureau of Geology And Mines Report Inv., No. 47, 22P.GlobalKimberlite, Central States, Alnoite
DS1970-0006
1970
Amos, D.H.Amos, D.H., Desborough, G.A.Mafic Intrusive Rocks of Precambrian Age in Southeast Missouriá#1Missouri Geological Survey And Water Resource Report Inv., No. 47, 22P.GlobalRelated Rocks, Petrology
DS1984-0736
1984
Amos, D.H.Trace, R.D., Amos, D.H.Stratigraphy and Structure of the Western Kentucky Fluorspar District.United States Geological Survey (USGS) PROF. PAPER., No. 1151-D, 41P.United States, Kentucky, AppalachiaRelated Rocks
DS2000-0018
2000
Amos, Q.G.Amos, Q.G.Resources and risk - a lender's viewMin. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 511-18.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS201709-2072
2017
Amos, R.Wilson, D., Amos, R., Blowes, D., Langman, J., Smith, L., Sego, D.Diavik waste rock project: scale up of a reactive transport conceptual model for temperature and sulfide dependent geochemical evolution.Goldschmidt Conference, abstract 1p.Canada, Northwest Territoriesdeposit, Diavik
DS201312-0157
2012
Amos, R.T.Chi, X., Amos, R.T., Stastna, M., Blowes, D.W., Sego, D.C., Smith, L.The Diavik waste rock project: implications of wind-induced gas transport.Applied Geochemistry, Vol. 36, pp. 246-255.Canada, Northwest TerritoriesDeposit - Diavik, environmental
DS201312-0705
2013
Amos, R.T.Pham, N.H., Sego, D.C., Arenson, L.U., Blowes, D.W., Amos, R.T., Smith, L.The Diavik waste rock project: measurement of the thermal regime of a waste rock test pile in a permafrost environment.Applied Geochemistry, Vol. 36, pp. 234-245.Canada, Northwest TerritoriesMining - Diavik
DS201801-0081
2018
Amos, R.T.Wilson, D., Amos, R.T., Blowes, D.W., Langman, J.B., Ptacek, C.J., Smith, L., Sego, D.C.Diavik waste rock project: a conceptual model for temperature and sulfide content dependent geochemical evolution of waste rock - Laboratory scale.Applied Geochemistry, Vol. 89, pp. 160-172.Canada, Northwest Territoriesdeposit - Diavik

Abstract: The Diavik Waste Rock Project consists of laboratory and field experiments developed for the investigation and scale-up of the geochemical evolution of sulfidic mine wastes. As part of this project, humidity cell experiments were conducted to assess the long-term geochemical evolution of a low-sulfide waste rock. Reactive transport modelling was used to assess the significant geochemical processes controlling oxidation of sulfide minerals and their dependence on temperature and sulfide mineral content. The geochemical evolution of effluent from waste rock with a sulfide content of 0.16 wt.% and 0.02 wt.% in humidity cells was simulated with the reactive transport model MIN3P, based on a conceptual model that included constant water flow, sulfide mineral content, sulfide oxidation controlled by the availability of oxidants, and subsequent neutralization reactions with carbonate and aluminosilicate minerals. Concentrations of Ni, Co, Cu, Zn, and SO4 in the humidity cell effluent were simulated using the shrinking core model, which represented the control of oxidant diffusion to the unreacted particle surface in the sulfide oxidation process. The influence of temperature was accounted for using the Arrhenius relation and appropriate activation energy values. Comparison of the experiment results, consisting of waste rock differentiated by sulfide mineral content and temperature, indicated surface area and temperature play important roles in rates of sulfide oxidation and release of sulfate and metals. After the model was calibrated to fit the effluent data from the higher sulfide content cells, subsequent simulations were conducted by adjusting only measured parameters, including sulfide mineral content and surface area.
DS201809-2115
2018
Amos, R.T.Wilson, D., Amos, R.T., Blowes, D.W., Langman, J.B., Smith, L., Sego, D.C.Diavik waste rock project: Scale up of a reactive transport model for temperature and sulfide content dependent geochemical evolution of waste rock.Applied Geochemisty, Vol. 96, pp. 177-190.Canada, Northwest Territoriesdeposit - Diavik

Abstract: The Diavik Waste Rock Project, located in a region of continuous permafrost in northern Canada, includes complementary field and laboratory experiments with the purpose of investigating scale-up techniques for the assessment of the geochemical evolution of mine waste rock at a large scale. As part of the Diavik project, medium-scale field experiments (?1.5?m high active zone lysimeters) were conducted to assess the long term geochemical evolution and drainage of a low-sulfide waste rock under a relatively simple (i.e. constrained by the container) flow regime while exposed to atmospheric conditions. A conceptual model, including the most significant processes controlling the sulfide-mineral oxidation and weathering of the associated host minerals as observed in a laboratory humidity cell experiment, was developed as part of a previous modelling study. The current study investigated the efficacy of scaling the calibrated humidity cell model to simulate the geochemical evolution of the active zone lysimeter experiments. The humidity cell model was used to simulate the geochemical evolution of low-sulfide waste rock with S content of 0.053?wt.% and 0.035?wt.% (primarily pyrrhotite) in the active zone lysimeter experiments using the reactive transport code MIN3P. Water flow through the lysimeters was simulated using temporally variable infiltration estimated from precipitation measurements made within 200?m of the lysimeters. Flow parameters and physical properties determined during previous studies at Diavik were incorporated into the simulations to reproduce the flow regime. The geochemical evolution of the waste-rock system was simulated by adjustment of the sulfide-mineral content to reflect the values measured at the lysimeters. The temperature dependence of the geochemical system was considered using temperature measurements taken daily, adjacent to the lysimeters, to correct weathering rates according to the Arrhenius equation. The lysimeter simulations indicated that a model developed from simulations of laboratory humidity cell experiments, incorporating detailed representations of temporally variable temperature and water infiltration, can be scaled to provide a reasonable assessment of geochemical evolution of the medium-scale field experiments.
DS201809-2116
2018
Amos, R.T.Wilson, D., Sinclair, S.A., Blowes, D.W., Amos,R.T., Smith, L., Sego, D.C.Diavik waste rock project: analysis of measured and simulated acid neutralization processes within a large scale field experiment.Goldschmidt Conference, 1p. AbstractCanada, Northwest Territoriesdeposit - Diavik

Abstract: The geochemical evolution of mine-waste rock often includes concurrent acid generation and neutralization processes. Deposition of mine-waste rock in large, oxygenated, and partially saturated piles can result in release of metals and decreased pH from weathering of sulfide minerals. Acid neutralization processes can often mitigate metals and pH impacts associated with sulfide oxidation. The Diavik Waste Rock Project included large field experiments (test piles built in 2006) conducted to characterize weathering of sulfide waste rock at a scale representative of full size waste-rock piles. Water samples from the unsaturated interior of one of the test piles, constructed of waste rock with ~0.05 wt.% S, were collected using soil water solution samplers and drains at the base of the pile. Field observations indicated pH decreased throughout the depth of the pile during 2008 and 2009 and that carbonate mineral buffering was entirely depleted by 2011 or 2012. Carbonate mineral exhaustion was accompanied by increased concentrations of dissolved Al and Fe in effluent samples collected at the basal drains. These results suggest that dissolution of Al and Fe(oxy)hydroxides occurred after the depletion of carbonate minerals following an acid neutralization sequence that is similar to observations made by previous researchers. A conceptual model of acid neutralization proceses within the pile, developed using physical and geochemical measurements conducted from 2008 to 2012, was used to inform reactive transport simulations conducted in 2017 to quantify the dominant acid neutralization processes within the test pile interior. Reactive transport simulations indicate that the conceptual model developed using the results of field samples provides a reasonable assessment of the evolution of the acid neutralization sequence.
DS1989-0098
1989
Amosse, J.Begou, P., Amosse, J., Fischer, W., Piboule, M.platinum group elements (PGE) distribution into the Lherz massive spinel peridotite (Ariege) France. Preliminary results.(in French)Comptes Rendus, (in French), Vol. 309, No. 11, October 12, pp.1177-1182FrancePlatinuM., Lherzolite
DS201112-0015
2011
Amoudry, L.O.Amoudry, L.O., Souza, A.J.Deterministic coastal morphological and sediment transport modeling: a review and discussion.Reviews of Geophysics, Vol. 49, 21p. RG2002GlobalSediment dynamics - not specific to diamonds but useful
DS2002-0027
2002
Amrhar, M.Amrhar, M.Syn-post collision Africa Europe paleostresses and deformation identified in the west high Atlas Mesozoic and Cenozoic cover Morocco.Comptes Rendus Geoscience, No. 334, 4, pp. 279-85.MoroccoTectonics
DS201212-0208
2012
Amri, I.Frets, E., Tommasi, A., Garrido, C.J., Padron-Navarta, J.A., Amri, I., Targuisti, K.Deformation processes and rheology of pyroxenites under lithospheric mantle conditions.Journal of Structural Geology, Vol. 39, pp. 138-157.Europe, Africa, MoroccoWebsterite, Beni-Bousera
DS201412-0253
2014
Amri, I.Frets, E.C., Tommasi, A., Garrido, C.J., Vauchez, A., Mainprice, D., Targuisti, K., Amri, I.The Beni Boussera peridotite ( Rif belt, Morocco): an oblique slip low angle shear zone thinning the subcontinental mantle lithosphere.Journal of Petrology, Vol. 55, 2, pp. 283-313.Africa, MoroccoPeridotite
DS201610-1850
2016
Amri, I.Chetoumani, K., Bondinier, J-L., Garrido, C.J., Marchesi, C., Amri, I., Targusiti, K.Spatial variability of pyroxenite layers in the Beni Bousera orogenic peridotite ( Morocco) and implications for their origin.Comptes Rendus Geoscience, in press available 11p.Africa, MoroccoPeridotite

Abstract: The Beni Bousera peridotite contains a diversity of pyroxenite layers. Several studies have postulated that at least some of them represent elongated strips of oceanic lithosphere recycled in the convective mantle. Some pyroxenites were, however, ascribed to igneous crystal segregation or melt-rock reactions. To further constrain the origin of these rocks, we collected 171 samples throughout the massif and examined their variability in relation with the tectono-metamorphic domains. A major finding is that all facies showing clear evidence for a crustal origin are concentrated in a narrow corridor of mylonitized peridotites, along the contact with granulitic country rocks. These peculiar facies were most likely incorporated at the mantle-crust boundary during the orogenic events that culminated in the peridotite exhumation. The other pyroxenites derive from a distinct protolith that was ubiquitous in the massif before its exhumation. They were deeply modified by partial melting and melt-rock reactions associated with lithospheric thinning.
DS201707-1314
2016
Amri, I.Chetouani, K., Bodinier, J-L., Garrido, C.J., Marchesi, C., Amri, I., Targuisti, K.Spatial variability of pyroxenite layers in the Beni Bousera orogenic peridotite ( Morocco) and implications for their origin.Comptes Rendus Geoscience, Vol. 348, pp. 619-629.Africa, Moroccoperidotite

Abstract: The Beni Bousera peridotite contains a diversity of pyroxenite layers. Several studies have postulated that at least some of them represent elongated strips of oceanic lithosphere recycled in the convective mantle. Some pyroxenites were, however, ascribed to igneous crystal segregation or melt–rock reactions. To further constrain the origin of these rocks, we collected 171 samples throughout the massif and examined their variability in relation with the tectono-metamorphic domains. A major finding is that all facies showing clear evidence for a crustal origin are concentrated in a narrow corridor of mylonitized peridotites, along the contact with granulitic country rocks. These peculiar facies were most likely incorporated at the mantle–crust boundary during the orogenic events that culminated in the peridotite exhumation. The other pyroxenites derive from a distinct protolith that was ubiquitous in the massif before its exhumation. They were deeply modified by partial melting and melt–rock reactions associated with lithospheric thinning.
DS201910-2243
2019
Amrstrong, K.Amrstrong, K., Frost, D.J., McCammon, C.A., Rubie, D.C., Boffa Ballaran, T.Deep magma ocean formation set the oxidation state of Earth's mantle.Science, Vol. 365, 6456, pp. 903-906.Mantleredox

Abstract: The composition of Earth’s atmosphere depends on the redox state of the mantle, which became more oxidizing at some stage after Earth’s core started to form. Through high-pressure experiments, we found that Fe2+ in a deep magma ocean would disproportionate to Fe3+ plus metallic iron at high pressures. The separation of this metallic iron to the core raised the oxidation state of the upper mantle, changing the chemistry of degassing volatiles that formed the atmosphere to more oxidized species. Additionally, the resulting gradient in redox state of the magma ocean allowed dissolved CO2 from the atmosphere to precipitate as diamond at depth. This explains Earth’s carbon-rich interior and suggests that redox evolution during accretion was an important variable in determining the composition of the terrestrial atmosphere.
DS201809-1989
2018
Amsellem, E.Amsellem, E., Moynier, F., Bertrand, H.Origin of carbonatites from Ca stable isotopes. (Oldoinyo Lengai)Goldschmidt Conference, 1p. AbstractAfrica, Tanzaniacarbonatites

Abstract: Carbonatites are rare igneous rocks that have a high content of carbonate minerals and nearly no silica. Carbonatitic magmas are derived from carbonated mantle sources but the origin of the carbonates (recycling of surface material or primary mantle source) is still debated. While mafic igneous rocks present a ?44/40Ca around 0.8-1.2‰ normalised to SRM, surface carbonates have ?44/40Ca ~ 0‰. Ca isotopes are therefore well suited to study the origin of Ca in carbonatites. We analysed the Ca isotopic composition of 25 carbonatites from continental and oceanic locations and from different ages (from 2 Ga to present day). The large majority of the carbonatites are isotopically light (?44/40Ca down to 0.07‰) compared to mantle derived rocks. On the other hand, the natrocarbonatite from Oldoinyo Lengai is isotopically heavier (?44/40Ca =0.82‰), similarly to basalts. Three mechanisms can explain the very light isotopic composition of the calciocarbonatites i) A very low degree of partial melting of the mantle may enrich the melt in light isotopes, yet there is no evidence of such large isotopic fractionation during partial melting. ii) The mantle source for the calciocarbonatites is enriched in light Ca likely due to recycling of surface material. iii) aqueous alteration has enriched the calciocarbonatites in the lighter isotopes. On the other hand, the natrocarbonatite from Oldoinyo Lengai have a MORB-like Ca isotopic composition. The difference of ?44/40Ca between natro- and calcio-carbonatite would then suggest that they either have different mantle sources, were formed from different degree of partial melting and/or that aqueous alteration has modified the Ca isotopic composition of calciocarbonatites.
DS202007-1122
2020
Amsellem, E.Amsellem, E., Moynier, F., Betrand, H., Bouyon, A., Mata, J., Tappe, S., Day, J.M.D.Calcium isotopic evidence for the mantle source of carbonatites.Science Adavances, Vol. 6, 63 eaba3269 6p. PdfMantlecarbonatite

Abstract: The origin of carbonatites—igneous rocks with more than 50% of carbonate minerals—and whether they originate from a primary mantle source or from recycling of surface materials are still debated. Calcium isotopes have the potential to resolve the origin of carbonatites, since marine carbonates are enriched in the lighter isotopes of Ca compared to the mantle. Here, we report the Ca isotopic compositions for 74 carbonatites and associated silicate rocks from continental and oceanic settings, spanning from 3 billion years ago to the present day, together with O and C isotopic ratios for 37 samples. Calcium-, Mg-, and Fe-rich carbonatites have isotopically lighter Ca than mantle-derived rocks such as basalts and fall within the range of isotopically light Ca from ancient marine carbonates. This signature reflects the composition of the source, which is isotopically light and is consistent with recycling of surface carbonate materials into the mantle.
DS202009-1605
2020
Amsellem, E.Amsellem, E., Moynier, F., Bertrand, H., Bouyon, A., Mata, J., Tappe, S., Day, J.M.D.Calcium isotopic evidence for the mantle sources of carbonatites. ( Oldoinyo Lengai)Science Advances, Vol. 6, eaba3269 June 3, 7p. PdfGlobal, Africa, Tanzaniacarbonatites

Abstract: The origin of carbonatites-igneous rocks with more than 50% of carbonate minerals-and whether they originate from a primary mantle source or from recycling of surface materials are still debated. Calcium isotopes have the potential to resolve the origin of carbonatites, since marine carbonates are enriched in the lighter isotopes of Ca compared to the mantle. Here, we report the Ca isotopic compositions for 74 carbonatites and associated silicate rocks from continental and oceanic settings, spanning from 3 billion years ago to the present day, together with O and C isotopic ratios for 37 samples. Calcium-, Mg-, and Fe-rich carbonatites have isotopically lighter Ca than mantle-derived rocks such as basalts and fall within the range of isotopically light Ca from ancient marine carbonates. This signature reflects the composition of the source, which is isotopically light and is consistent with recycling of surface carbonate materials into the mantle.
DS1984-0010
1984
Amshinakiy, A.N.Amshinakiy, A.N., Eomin, A.M.Significance of pyropes in slime mineralogical methods of prospecting for kimberlite pipes. (Russian)Rudn. Spets. Osad. Form. Sib., (Russian), pp. 17-26RussiaGarnets, Prospecting Methods
DS1983-0010
1983
Amshinskii, A.N.Amshinskii, A.N., Pokhilenko, N.P.Some Distinctive Features of the Composition of Picrolimenites from the Zarnitsa Kimerlite Pipe (yakutia).Soviet Geology and GEOPHYSICS, Vol. 24, No. 11, PP. 106-110.RussiaMineralogy
DS1986-0017
1986
Amshinskii, A.N.Amshinskii, A.N.Relation between oxidation of diamond and secondary changes in ilmenite in kimberlites (Russian)Nauka Sib. Otd. Geterog. Porod. Rud Sib., (Russian), pp. 91-102RussiaBlank
DS1987-0005
1987
Amshinskiy, A.N.Amshinskiy, A.N., Kuigin, S.S., Rodionov, A.S.The significance of the volume of analyzed selections of accessory minerals of diamonds to characterize kimberlite bodies. (Russian)In: Methods for studying and modeling geol. phenomena, Akad. Nauk SSSR, pp. 5-16RussiaDiamond inclusions
DS1988-0582
1988
Amshinskiy, A.N.Rodionov, A.S., Amshinskiy, A.N., Pokhilenko, N.P.Ilmenite-pyrope wehrlites: a new type of paragenesis in xenoliths fromkimberliteSoviet Geology and Geophysics, Vol. 29, No. 7, pp. 48-51RussiaXenoliths, Wehrlites
DS1997-0368
1997
AmtauerGaranin, V.K., Dummett, Amtauer, Kudryavtseva, FipkeInternal structure and spectroscopic characteristics of diamonds from Lomonosov deposit.Doklady Academy of Sciences, Vol. 353, No. 2, Feb-Mar, pp. 233-5.Russia, Kola PeninsulaDiamond - morphology, Deposit - Lomonosov
DS1975-0175
1975
Amthauer, G.Rost, F., Beerman, E., Amthauer, G.Chemical Investigation of Pyrope Garnets in the Stockdale Kimberlite Intrusion, Riley County, Kansas.American MINERALOGIST., Vol. 60, PP. 675-680.KansasKimberlite, Central States
DS201602-0205
2015
Amulele, G.Girard, J., Amulele, G., Farla, R., Mohiuddin, A., Karato, S-i.Shear deformation of bridgmanite and magnesiowustite aggregates at lower mantle conditions.Science, Vol. 351, 6269, pp. 144-147.MantleRheology

Abstract: Rheological properties of the lower mantle have strong influence on the dynamics and evolution of Earth. By using the improved methods of quantitative deformation experiments at high pressures and temperatures, we deformed a mixture of bridgmanite and magnesiowüstite under the shallow lower mantle conditions. We conducted experiments up to about 100% strain at a strain rate of about 3 × 10(-5) second(-1). We found that bridgmanite is substantially stronger than magnesiowüstite and that magnesiowüstite largely accommodates the strain. Our results suggest that strain weakening and resultant shear localization likely occur in the lower mantle. This would explain the preservation of long-lived geochemical reservoirs and the lack of seismic anisotropy in the majority of the lower mantle except the boundary layers.
DS1986-0018
1986
Amundsen, H.E.F.Amundsen, H.E.F.Co-existing carbonatitic, ultramafic and mafic melts in the evdience from spinel lherzolite xenoliths, northwest SpitzbergenProceedings of the Fourth International Kimberlite Conference, Held, No. 16, pp. 160-162NorwayCarbonatite
DS1987-0006
1987
Amundsen, H.E.F.Amundsen, H.E.F.Peridotite xenoliths from Gran Canaria Canary Islands, evidence for metasomatic processes and partial melting in the lower oceanic crustNeues Jahrbuch f?r Mineralogie, Vol. 156, No. 2, pp. 121-140GlobalGeochemistry, Peridotite xenoliths
DS1992-0023
1992
Amundsen, H.E.F.Amundsen, H.E.F., Neumann, E.R.Redox control during mantle/ melt interactionGeochimica et Cosmochimica Acta, Vol. 56, pp. 2405-2416MantleRedox, Melt interaction, lherzolite
DS1994-0043
1994
An, P.An, P., Moon, W.M., Bonham-Carter, G.F.An object-oriented knowledge representation structure for exploration dataintegrationNonrenewable Resources, Vol. 3, No. 2, Summer, pp. 132-145GlobalBase metals, sulphides, Geostatistics -database
DS1994-0044
1994
An, P.An, P., Moon, W.M., Bonham-Carter, G.F.Uncertainty management in integration of exploration dat a using the BeliefFunctionNonrenewable Resources, Vol. 3, No. 1, Spring, pp. 60-71GlobalEBF function, Geostatistics
DS1995-0033
1995
An, P.An, P., Chung, G.F., Rencz, A.N.Digital lithology mapping from airborne geophysical and remote sensing data in the Melville PeninsulaRemote Sensing of Environment, Vol. 53, No. 2, Aug. pp. 76-84Northwest Territories, Melville PeninsulaGeophysics -airborne, Remote sensing
DS1995-0416
1995
An, V.V.Devyatkin, V.N., An, V.V.Permafrost -thermal conditions of kimberlite tubes of YakutiaProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 132-4.Russia, Siberia, Daldyn Alakit, Malo-BotubaGeothermometry, Structure
DS201610-1872
2016
An, Y.Huang, J-X., Xiang, Y., An, Y., Griffin, W.L., Greau, Y., Xie, L., Pearson, N.J., Yu, H., O'Reilly, S.Y.Magnesium and oxygen isotopes in Roberts Victor eclogites.Chemical Geology, Vol. 438, pp. 73-83.Africa, South AfricaDeposit - Roberts Victor

Abstract: Magnesium and oxygen are critical elements in the solid Earth and hydrosphere. A better understanding of the combined behavior of Mg and O isotopes will refine their use as a tracer of geochemical processes and Earth evolution. In this study, the Mg-isotope compositions of garnet and omphacite separated from well-characterized xenolithic eclogites from the Roberts Victor kimberlite pipe (South Africa) have been measured by solution multi-collector ICP-MS. The reconstructed whole-rock ?26Mg values of Type I (metasomatized) eclogites range from ? 0.61‰ to ? 0.20‰ (Type IA) and from ? 0.60‰ to ? 0.30‰ (Type IB) (mean ? 0.43‰ ± 0.12‰), while ?26Mg of Type IIA (fresh, least metasomatized) eclogites ranges from ? 1.09‰ to ? 0.17‰ (mean ? 0.69‰ ± 0.41‰); a Type IIB (fresh, least metasomatized) has ?26Mg of ? 0.37‰. Oxygen-isotope compositions of garnet were analyzed in situ by SIMS (CAMECA 1280) and cross-checked by laser fluorination. Garnets have ?18O of 6.53‰ to 9.08‰ in Type IA, 6.14‰ to 6.65‰ in Type IB, and 2.34‰ to 2.91‰ in Type IIB. The variation of ?26Mg and ?18O in Type IA and IB eclogites is consistent with the previously proposed model for the evolution of these samples, based on major and trace elements and radiogenic isotopes. In this model, the protoliths (Type II eclogites) were metasomatized by carbonatitic to kimberlitic melts/fluids to produce first Type IA eclogites and then Type IB. Metasomatism has changed the O-isotope compositions, but the Mg-isotope compositions of Type IA are mainly controlled by the protoliths; those of Type IB eclogites reflect mixing between the protoliths and the kimberlitic melt/fluid. The combination of a large range of ?26Mg and low ?18O in Type II eclogites cannot be explained easily by seawater alteration of oceanic crust, interaction of carbonate/silicate sediments with oceanic crust, or partial melting of mafic rocks.
DS201701-0002
2016
An, Y.An, Y., Huang, J-X., Griffin, W.L., Liu, C., Huang, F.Isotopic composition of Mg and Fe in garnet peridotites from the Kaapvaal and Siberian cratons.Geochimica et Cosmochimica Acta, in press available 45p.Africa, RussiaGeochronology

Abstract: We present Mg and Fe isotopic data for whole rocks and separated minerals (olivine, clinopyroxene, orthopyroxene, garnet, and phlogopite) of garnet peridotites that equilibrated at depths of 134-186 km beneath the Kaapvaal and Siberian cratons. There is no clear difference in ?26Mg and ?56Fe of garnet peridotites from these two cratons. ?26Mg of whole rocks varies from ?0.243‰ to ?0.204‰ with an average of ?0.225 ± 0.037‰ (2?, n = 19), and ?56Fe from ?0.038‰ to 0.060‰ with an average of ?0.003 ± 0.068‰ (2?, n = 19). Both values are indistinguishable from the fertile upper mantle, indicating that there is no significant Mg-Fe isotopic difference between the shallow and deep upper mantle. The garnet peridotites from ancient cratons show ?26Mg similar to komatiites and basalts, further suggesting that there is no obvious Mg isotopic fractionation during different degrees of partial melting of deep mantle peridotites and komatiite formation. The precision of the Mg and Fe isotope data (?±0.05‰ for ?26Mg and ?56Fe, 2?) allows us to distinguish inter-mineral isotopic fractionations. Olivines are in equilibrium with opx in terms of Mg and Fe isotopes. Garnets have the lowest ?26Mg and ?56Fe among the coexisting mantle minerals, suggesting the dominant control of crystal structure on the Mg-Fe isotopic compositions of garnets. Elemental compositions and mineralogy suggest that clinopyroxene and garnet were produced by later metasomatic processes as they are not in chemical equilibrium with olivine or orthopyroxene. This is consistent with the isotopic disequilibrium of Mg and Fe isotopes between orthopyroxene/olivine and garnet/clinopyroxene. Combined with one sample showing slightly heavy ?26Mg and much lighter ?56Fe, these disequilibrium features in the garnet peridotites reveal kinetic isotopic fractionation due to Fe-Mg inter-diffusion during reaction between peridotites and percolating melts in the Kaapvaal craton.
DS201702-0192
2017
An, Y.An, Y., Huang, J-X., Griffin, W.L., Liu, C., Huang, F.Isotopic composition of Mg and Fe in garnet peridotites from the Kaapvaal and Siberian cratons.Geochimica et Cosmochimica Acta, Vol. 200, pp. 167-185.Africa, South Africa, RussiaMetasomatism

Abstract: We present Mg and Fe isotopic data for whole rocks and separated minerals (olivine, clinopyroxene, orthopyroxene, garnet, and phlogopite) of garnet peridotites that equilibrated at depths of 134-186 km beneath the Kaapvaal and Siberian cratons. There is no clear difference in ?26Mg and ?56Fe of garnet peridotites from these two cratons. ?26Mg of whole rocks varies from ?0.243 to ?0.204 with an average of ?0.225 ± 0.037 (2?, n = 19), and ?56Fe from ?0.038‰ o 0.060 with an average of ?0.003 ± 0.068 (2?, n = 19). Both values are indistinguishable from the fertile upper mantle, indicating that there is no significant Mg-Fe isotopic difference between the shallow and deep upper mantle. The garnet peridotites from ancient cratons show ?26Mg similar to komatiites and basalts, further suggesting that there is no obvious Mg isotopic fractionation during different degrees of partial melting of deep mantle peridotites and komatiite formation. The precision of the Mg and Fe isotope data (±0.05 for ?26Mg and ?56Fe, 2?) allows us to distinguish inter-mineral isotopic fractionations. Olivines are in equilibrium with opx in terms of Mg and Fe isotopes. Garnets have the lowest ?26Mg and ?56Fe among the coexisting mantle minerals, suggesting the dominant control of crystal structure on the Mg-Fe isotopic compositions of garnets. Elemental compositions and mineralogy suggest that clinopyroxene and garnet were produced by later metasomatic processes as they are not in chemical equilibrium with olivine or orthopyroxene. This is consistent with the isotopic disequilibrium of Mg and Fe isotopes between orthopyroxene/olivine and garnet/clinopyroxene. Combined with one sample showing slightly heavy ?26Mg and much lighter ?56Fe, these disequilibrium features in the garnet peridotites reveal kinetic isotopic fractionation due to Fe-Mg inter-diffusion during reaction between peridotites and percolating melts in the Kaapvaal craton.
DS201704-0617
2017
An, Y.An, Y., Huang, J-X., Griffin, W.L.,Liu, C., Huang, F.Isotopic composition of Mg and Fe in garnet peridotites from the Kaapvaal and Siberian cratons.Geochimica et Cosmochimica Acta, Vol. 200, pp. 167-185.Africa, South Africa, RussiaCraton, Peridotite

Abstract: We present Mg and Fe isotopic data for whole rocks and separated minerals (olivine, clinopyroxene, orthopyroxene, garnet, and phlogopite) of garnet peridotites that equilibrated at depths of 134-186 km beneath the Kaapvaal and Siberian cratons. There is no clear difference in ?26Mg and ?56Fe of garnet peridotites from these two cratons. ?26Mg of whole rocks varies from ?0.243‰ to ?0.204‰ with an average of ?0.225 ± 0.037‰ (2?, n = 19), and ?56Fe from ?0.038‰ 0.060 with an average of ?0.003 ± 0.068‰ (2?, n = 19). Both values are indistinguishable from the fertile upper mantle, indicating that there is no significant Mg-Fe isotopic difference between the shallow and deep upper mantle. The garnet peridotites from ancient cratons show ?26Mg similar to komatiites and basalts, further suggesting that there is no obvious Mg isotopic fractionation during different degrees of partial melting of deep mantle peridotites and komatiite formation. The precision of the Mg and Fe isotope data (?±0.05‰ for ?26Mg and ?56Fe, 2?) allows us to distinguish inter-mineral isotopic fractionations. Olivines are in equilibrium with opx in terms of Mg and Fe isotopes. Garnets have the lowest ?26Mg and ?56Fe among the coexisting mantle minerals, suggesting the dominant control of crystal structure on the Mg-Fe isotopic compositions of garnets. Elemental compositions and mineralogy suggest that clinopyroxene and garnet were produced by later metasomatic processes as they are not in chemical equilibrium with olivine or orthopyroxene. This is consistent with the isotopic disequilibrium of Mg and Fe isotopes between orthopyroxene/olivine and garnet/clinopyroxene. Combined with one sample showing slightly heavy ?26Mg and much lighter ?56Fe, these disequilibrium features in the garnet peridotites reveal kinetic isotopic fractionation due to Fe-Mg inter-diffusion during reaction between peridotites and percolating melts in the Kaapvaal craton.
DS200712-0014
2006
An Meijian, A.An Meijian, A., Shi, Y.Lithospheric thickness of the Chinese continent.Physics of the Earth and Planetary Interiors, Vol. 159, 3-4, Dec. pp. 257-266.ChinaGeothermometry, Geophysics - seismics
DS1994-1576
1994
An YinShangyou Nie, An Yin, Rowley, D.B., Yugan JinExhumation of the Dabie Shan ultra high pressure rocks and accumulation Of the Songpan Ganzi flysch sequence.Geology, Vol. 22, No. 11, November pp. 999-1002.ChinaMetamorphic rocks, Diamonds
DS200812-0027
2008
Analytical ChemistryAnalytical ChemistryWhy does the Hope diamond glow red? Despite old rumors, chemistry - not a curse is the key.Analytical Chemistry, Vol. 80, 7,pp. 2295-2296.TechnologyDiamond notable - Hope
DS201708-1568
2017
Anand, A.Dalrymple, W., Anand, A.Koh-i-Noor. Historyexpressbookshop.co.uk, book - cost approx. 17 lbsIndiadiamond notable, Koh-i-noor

Abstract: The first comprehensive and authoritative history of the Koh-i Noor, arguably the most celebrated and mythologised jewel in the world. On 29 March 1849, the ten-year-old Maharajah of the Punjab was ushered into the magnificent Mirrored Hall at the centre of the great Fort in Lahore. There, in a public ceremony, the frightened but dignified child handed over to the British East India Company in a formal Act of Submission to Queen Victoria not only swathes of the richest land in India, but also arguably the single most valuable object in the subcontinent: the celebrated Koh-i Noor diamond.
DS2002-1581
2002
Anand, M.Taylor, L.A., Sobolev, N..V., Ghazi, M., Anand, M., Bodner, R.J.The science of diamonds and their inclusions can such dat a be used to establish diamond provenance?Eos, American Geophysical Union, Spring Abstract Volume, Vol.83,19, 1p.BrazilDiamond - inclusions, sulphides
DS2003-0013
2003
Anand, M.Anand, M., Gibson, S.A., Subbarao, K.V., Kelley, S.P., Dickin, A.P.Early Proterozoic melt generation processes beneath the intra-cratonic CuddapahJournal of Petrology, Vol. 44, 12, pp. 2139-2172.IndiaMetasomatism
DS2003-0014
2003
Anand, M.Anand, M., Taylor, L.A., Carlson, R.C., Taylor, D-H., Sobolev, N.V.Diamond genesis revealed by x-ray tomography of Diamondiferous eclogites8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractRussia, Siberia, YakutiaEclogites and Diamonds
DS2003-0015
2003
Anand, M.Anand, M., Taylor, L.A., Misra, K.C., Carlson, W.D., Sobolev, N.V.Diamondiferous eclogite dissections: anomalous diamond genesis?8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractRussia, YakutiaEclogites, diamonds, Genesis
DS2003-1114
2003
Anand, M.Promprated, P., Taylor, L.A., Floss, C., Malkovets, V.G., Anand, M., GriffinDiamond inclusions from Snap Lake, NWT, Canada8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractNorthwest TerritoriesDiamonds - inclusions, Deposit - Snap Lake
DS2003-1363
2003
Anand, M.Taylor, L.A., Anand, M., Promprated, P.Diamonds and their inclusions: are the criteria for syngenesis valid?8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractGlobalDiamonds - inclusions, Genesis
DS2003-1364
2003
Anand, M.Taylor, L.A., Anand, M., Promprated, P., Floss, C., Sobolev, N.V.The significance of mineral inclusions in large diamonds from Yakutia, RussiaAmerican Mineralogist, Vol. 88, 5/6, pp. 912-928.Russia, YakutiaDiamond - inclusions, protogenetic, Deposit - Udachnaya, Mir, Aikhal
DS2003-1366
2003
Anand, M.Taylor, L.A., Spetsius, Z.A., Wiesli, R., Anand, M., Promprated, P., Valley, J.The origin of mantle peridotites: crustal signatures from Yakutian kimberlites8ikc, Www.venuewest.com/8ikc/program.htm, Session 4, POSTER abstractRussia, YakutiaMantle geochemistry
DS200412-0025
2003
Anand, M.Anand, M., Gibson, S.A., Subbarao, K., Kelly, S.P., Dickin, A.P.Early Proterozoic melt generation processes beneath the intra cratonic Cuddapah Basin, southern India.Journal of Petrology, Vol. 44, pp. 2139-2171.IndiaCraton, melting
DS200412-0026
2003
Anand, M.Anand, M., Gibson, S.A., Subbarao, K.V., Kelley, S.P., Dickin, A.P.Early Proterozoic melt generation processes beneath the intra-cratonic Cuddapah Basin, southern India.Journal of Petrology, Vol. 44, 12, pp. 2139-2172.IndiaMetasomatism
DS200412-0027
2004
Anand, M.Anand, M., Taylor, L.Xenoliths - a diamond's nest. Opportunities to study diamonds still trapped in mantle fragments are rare. Examining the 3-D spatRough Diamond Review, No. 5, June, pp.TechnologyXenoliths
DS200412-0028
2003
Anand, M.Anand, M., Taylor, L.A., Misra, K.C., Carlson, W.D., Sobolev, N.V.Diamondiferous eclogite dissections: anomalous diamond genesis?8 IKC Program, Session 2, AbstractRussia, YakutiaEclogite, diamonds Genesis
DS200412-0029
2004
Anand, M.Anand, M., Taylor, L.A., Misra, K.C., Carlson, W.D., Sobolev, N.V.Nature of diamonds in Yakutian eclogites: views from eclogite tomography and mineral inclusions in diamonds.Lithos, Vol. 77, 1-4, Sept. pp. 333-348.Russia, YakutiaUdachnaya, diamond inclusions, eclogte, xenoliths
DS200412-1335
2004
Anand, M.Misra, K.C., Anand, M., Taylor, L.A., Sobolev, N.V.Multi stage metasomatism of Diamondiferous eclogite xenoliths from the Udachnaya kimberlite pipe, Yakutia, Siberia.Contributions to Mineralogy and Petrology, Vol. 146, 6, pp. 696-714.Russia, Siberia, YakutiaDeposit - Udachnaya
DS200412-1592
2004
Anand, M.Promprated, P., Taylor, L.A., Anand, M., Floss, C., Sobolev, N.V., Pokhilenko, N.P.Multiple mineral inclusions in diamonds from the Snap Lake/King Lake kimberlite dike, Slave Craton: a trace element perspective.Lithos, Vol. 77, 1-4, Sept. pp. 69-81.Canada, Northwest TerritoriesDiamond inclusions, trace element, REE, in situ analysi
DS200412-1971
2004
Anand, M.Taylor, L.A., Anand, M.Diamonds: time capsules from the Siberian mantle.Chemie der Erde, Vol. 64, 1, pp. 1-74.RussiaDiamond - geochronology
DS200412-1972
2003
Anand, M.Taylor, L.A., Anand, M., Promprated, P.Diamonds and their inclusions: are the criteria for syngenesis valid?8 IKC Program, Session 2, AbstractTechnologyDiamonds - inclusions Genesis
DS200412-1973
2003
Anand, M.Taylor, L.A., Anand, M., Promprated, P., Floss, C., Sobolev, N.V.The significance of mineral inclusions in large diamonds from Yakutia, Russia.American Mineralogist, Vol. 88, 5/6, pp. 912-928.Russia, YakutiaDiamond - inclusions, protogenetic Deposit - Udachnaya, Mir, Aikhal
DS200412-1974
2003
Anand, M.Taylor, L.A., Snyder, G.A., Keller, R., Remley, D.A., Anand,M., Wiesli, R., Valley, J., Sobolev, N.V.Petrogenesis of Group A eclogites and websterites: evidence from the Obnazhennaya kimberlite, Yakutia.Contributions to Mineralogy and Petrology, Vol. 145, pp. 424-443.Russia, YakutiaPetrology, genesis Deposit - Obnazhennaya
DS200612-0237
2005
Anand, M.Chalapathi Rao, N.V., Burgess, R., Anand, M., Mainkar, D.Evidence for a Phanerozoic (478 Ma) Diamondiferous kimberlite emplacement epoch in the Indian Shield from 40 Ar/ 39Ar dating of the Kodomali kimberlite: implications ....Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 103-106.India, Bastar Craton, RodiniaTectonics - Kodomali, Pan African , Geothermometry
DS201012-0097
2010
Anand, M.Chalapathi Rao, N.V., Anand, M., Dongre, A., Osborne, I.Carbonate xenoliths hosted by the Mesoproterozoic Siddanpalli kimberlite cluster ( Eastern Dharwar craton): implications for the geodynamic evolution ofInternational Journal of Earth Sciences, Vol. 99, pp. 1791-1804.IndiaDiamond and uranium metallogenesis
DS201112-0763
2011
Anand, M.Osborner, I., Sherlock, S., Anand, M., Argles, T.New Ar-Ar ages of southern Indian kimberlites and a lamproite and their geochemical evolution.Precambrian Research, Vol. 189, pp. 91-103.IndiaGeochronology
DS201706-1087
2017
Anand, P.Kumar, R., Bansal, A.R., Anand, P., Rao, V.K., Singh, U.Mapping of magnetic basement in the central India from aeromagnetic dat a for scaling geology.Geophysical Prospecting, in press availableIndiageophysics - aermagnetics

Abstract: The Central Indian region is having complex geology covering the Godavari Graben, the Bastar Craton (including the Chhattisgarh Basin), the Eastern Ghat Mobile Belt, the Mahanadi Graban and some part of the Deccan Trap, the Northern Singhbhum Orogen and the Eastern Dharwar Craton. The region is well covered by reconnaissance scale aeromagnetic data, analyzed for the estimation of basement and shallow anomalous magnetic sources depth using scaling spectral method. The shallow magnetic anomalies are found to vary from 1 to 3 km whereas magnetic basement depth values are found to vary from 2 to 7 km. The shallowest basement depth of 2 km corresponds to the Kanker granites, a part of the Bastar Craton, whereas deepest basement depth of 7 km is for the Godavari Basin and the southeastern part of the Eastern Ghat Mobile Belts near the Parvatipuram Bobbili fault. The estimated basement depth values correlate well with the values found from earlier geophysical studies. The earlier geophysical studies are limited to few tectonic units whereas our estimation provides detailed magnetic basement mapping in the region. The magnetic basement and shallow depth values in the region indicate complex tectonic, heterogeneity and intrusive bodies at different depth which can be attributed to different thermo-tectonic processes since Precambrian.
DS200712-0194
2007
Anand, R.Cohen, D.R., Kelley, D.L., Anand, R., Coker, W.B.Major advances in exploration geochemistry. 1998- 2007.Proceedings of Exploration 07 edited by B. Milkereit, pp. 3-18.TechnologyGeochemistry - review
DS1995-0034
1995
Anand, R.R.Anand, R.R.Genesis and classification of ferruginous regolith materials in the YilgarnCraton: implications for minExplore, No. 89, October pp. 3-7AustraliaMineral exploration, Regoliths
DS1997-0026
1997
Anand, R.R.Anand, R.R., Phang, C., Wildman, J.E., Lintern, M.J.Genesis of some calcretes in the southern Yilgarn Craton: implications for mineral explorationAustralian Journal of Earth Sciences, Vol. 44, No. 1, Feb. pp. 87-104AustraliaCraton, Calcretes
DS2002-0031
2002
Anand, R.R.Anand, R.R., Paine, M.Regolith geology of the Yilgarn Craton, Western Australia: implications for explorationAustralian Journal of Earth Sciences, Vol.49,1,pp.3-162.AustraliaRegolith - geochemistry, overview
DS1991-0002
1991
Anand, S.Acharya, S., Anand, S., Reddy, B.R., Das, R.P.Processing of kimberlite tailings to recover magnesium as MgO or MgSO417th. International Mineral Proceedings Congress, Preprints, pp. 199-209.IndiaMineral processing, Kimberlite tailinsg -magnesiuM.
DS1991-1403
1991
Anand, S.Reddy, B.R., Acharya, S., Anand, S., Das, R.P.Preparation and characterization of magnesium sulfate heptahydrate From kimberlite tailingsJournal of Thermal Analysis, Vol. 37, No. 5, May pp. 945-951GlobalMining, Mineral processing -tailings
DS1970-0220
1971
Anand, S.N.Anand, S.N.Geological and Geophysical Investigations of Diamondiferous volcanic Pipe Rocks from the Lattavaram Area, Anantapur District, Andhra Pradesh.India Geological Survey Miscellaneous Report, No. 19, PP. 128-133.India, Andhra PradeshKimberlite, Geophysics
DS2002-0032
2002
Anand, S.P.Anand, S.P., Rajaram, M.Aeromagnetic dat a to probe the Dharwar CratonCurrent Science, Vol.83,2,Julyy 25, p. 162-66.IndiaGeophysics - magnetics, Craton
DS200412-0030
2002
Anand, S.P.Anand, S.P.Delineation of crustal structure of Nahandi Basin from ground magnetic survey.Journal Geological Society of India, Vol. 60, 3, pp. 283-292.IndiaGeophysics - magnetics, total field anomaly map
DS200412-0031
2003
Anand, S.P.Anand, S.P., Rajaram, M.Crustal perspective of Narmada-Son lineament: an aeromagnetic perspective.Earth Planets and Space, Vol. 56, 5, pp. e9-e12. IngentaIndiaGeophysics - magnetics
DS200412-1612
2003
Anand, S.P.Rajaram, M., Anand, S.P.Central Indian tectonics revisited using aeromagnetic data.Earth Planets and Space, Vol. 55, 12, pp. e1-e4. Ingenta 1035538701IndiaGeophysics - magnetics, Namada Son lineament , dyke swa
DS200912-0610
2009
Anand, S.P.Rajaram, M., Anand, S.P., Hermant, K., Purucker, M.E.Currie isotherm map of Indian subcontinent from satellite and aeromagnetic data.Earth and Planetary Science Letters, Vol. 281, 3-4, May 15, pp. 147-158.IndiaGeophysics - magnetics
DS201312-0730
2013
Anand, S.P.Rajaram, M., Anand, S.P.Aeromagnetic signatures of Precambrian shield and suture zones of Peninsular India.Geoscience Frontiers, in press availableIndiaGeophysics
DS201801-0033
2018
Anand, S.P.Kumar, R., Bansal, A.R., Anand, S.P., Rao, V.K., Singh, U.K.Mapping of magnetic basement in central India from aeromagnetic dat a for scaling geology. Bastar Craton including Chhattisgarth basin.Geophysical Prospecting, Vol. 66, 1, pp. 226-239.Indiageophysics - magnetics

Abstract: The Central Indian region has a complex geology covering the Godavari Graben, the Bastar Craton (including the Chhattisgarh Basin), the Eastern Ghat Mobile Belt, the Mahanadi Graben and some part of the Deccan Trap, the northern Singhbhum Orogen and the eastern Dharwar Craton. The region is well covered by reconnaissance-scale aeromagnetic data, analysed for the estimation of basement and shallow anomalous magnetic sources depth using scaling spectral method. The shallow magnetic anomalies are found to vary from 1 to 3 km, whereas magnetic basement depth values are found to vary from 2 to 7 km. The shallowest basement depth of 2 km corresponds to the Kanker granites, a part of the Bastar Craton, whereas the deepest basement depth of 7 km is for the Godavari Basin and the southeastern part of the Eastern Ghat Mobile Belt near the Parvatipuram Bobbili fault. The estimated basement depth values correlate well with the values found from earlier geophysical studies. The earlier geophysical studies are limited to few tectonic units, whereas our estimation provides detailed magnetic basement mapping in the region. The magnetic basement and shallow depth values in the region indicate complex tectonic, heterogeneity, and intrusive bodies at different depths, which can be attributed to different thermo-tectonic processes since Precambrian.
DS2003-1365
2003
Anand. M.Taylor, L.A., Snyder, G.A., Keller, R., Remley, D.A., Anand. M., Wiesli, R.Petrogenesis of Group A eclogites and websterites: evidence from the ObnazhennayaContributions Mineralogy and Petrology, Vol.Russia, YakutiaPetrology, genesis, Deposit - Obnazhennaya
DS201412-0008
2014
Ananda Reddy, R.Ananda Reddy, R.Qualitative analysis of mafic dyke swarms and kimberlites from morphological and geophysical signatures, NW of Proterozoic Cuddapah basin, eastern Dharwar craton.Journal of the Geological Society of India, Vol. 83, 3, pp. 235-251.IndiaDeposit - Narayanpet
DS201607-1325
2016
Ananda Reddy, R.Ananda Reddy, R.Geophysical signatures over concealed kimberlite pipes from South Indian diamond province.IGC 35th., Session A Dynamic Earth 1p. AbstractIndiaGeophysics
DS1998-0027
1998
Ananiev, V.A.Ananiev, V.A., Kuligin, S.S., Reimers, L.F., Khlestov, V.Paragenetic analysis of the upper mantle minerals from the heavy mineral concentrates of kimberlites ....7th International Kimberlite Conference Abstract, pp. 14-16.Russia, YakutiaMineralogy - paragenesis, xenoliths, Deposit - Udachnaya
DS201312-0343
2012
Ananth Rao, D.Guha, A., Ananth Rao, D., Ravi, S., Kumar, K.V., Dhananjaya Rao, E.N.Analysis of the potential of kimberlite rock spectra as spectral end member using samples from Narayanpet kimberlite field, Andhra Pradesh.Current Science, Vol. 103, 9, Nov. 10, pp. 1096-1104.IndiaDeposit - Narayanpet
DS200712-1003
2006
Ananyev, S.Smirnov, S., Ananyev, S., Kalinia, V., Vins, V.Color grading of color enhanced natural diamonds: a case study of Imperial red diamonds.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.126-7. abstract onlyTechnologyColour grading
DS201312-0018
2013
Anashkin, S.Anashkin, S., Bovkun, A.,Bindi, L., Garanin, V.,Litvin, Y.Kudryavtsevaite - a new kimberlitic mineral.Mineralogical Magazine, Vol. 77, 3, pp. 327-334.TechnologyMineral chemistry
DS201212-0229
2012
Anashkin, S.M.Garanin, V.K., Anashkin, S.M., Bovkun, A.V., Jelsma, H., Shmakov, I.I., Garanin, K.V.Groundmass microcrystalline oxides from the Marsfontein pipe ( RSA) , Catoca, Camachia and other Angolan kimberlite pipes.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, Angola, South AfricaDeposit - Marsfontein, Catoca, Camachia
DS201312-0019
2013
Anashkin, S.M.Anashkin, S.M., Bovkum, A.V., Litvin, Yu.A., Garanin, V.K.the intraplate character of supercontinent tectonics.Doklady Earth Sciences, Vol. 451, 2, pp. 849-854.MantleTectonics
DS201607-1287
2016
Anashkina, N.E.Bunin, I. Zh., Chanturia, V.A., Anashkina, N.E., Ryazantseva, M.V.Experimental validation of mechanism for pulsed energy effect on structure, chemical properties and microhardness of rock forming minerals of kimberlites.Journal of Mining Science, Vol. 51, 4, pp. 799-810.RussiaSpectroscopy

Abstract: Using the Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), microscopy and microhardness test methods, the change in the crystalline and chemical properties and in microhardness of rock-forming minerals of kimberlites as a result of exposure to high-power nanosecond electromagnetic pulses (HPEM) has been studied. From FTIR and XPS data the non-thermal effect of HPEM results in damage of surface microstructure of dielectric minerals due to formation of microcracks, surface breakdowns and other defects, which ensure effective weakening of rock-forming minerals and reduction in their microhardness by 40-66%.
DS200912-0005
2008
Anastasenko, G.F.Anastasenko, G.F., Leybov, M.B.Diamonds of Russia.Rocks and Minerals, Vol. 83, 6, pp. 508-517.RussiaBrief overview
DS1996-0024
1996
Anastasio, D.Anastasio, D., Erslev, E., Fisher, D.M.Fault related folding. Brief overview of a Penrose ConferenceGsa Today, Vol. 6, No. 2, Feb. pp. 14-15GlobalFolding, Structure -faulting
DS1991-1293
1991
Anastassi, E.Papadopoulos, A.D., Anastassi, E.Optical properties of diamondPhys. Rev. B., Vol. 43, No. 6, Feb. 15, pp. 5090-5097GlobalMineralogy -optical properties, Diamond
DS1983-0362
1983
ANAYEV, S.a.Konovalenko, S.I., Rossovskiim l.n., ANAYEV, S.a.Jeremejevite: New Discovery of the Mineral in Russia.(russian)Zap. Vses Mineral. Obshch., (Russian), Vol. 117, No. 2, pp. 212-217RussiaMineralogy
DS1991-1816
1991
Anayev, V.V.Volynets, O.N., Anayev, V.V.Chromian amphiboles and micas in ultramafic inclusions in Quaternary lavas of Kamchatka and the KurilesDoklady Academy of Sciences, Earth Sci. Section, Vol. 307, No. 1-6, pp. 168-171GlobalMineral chemistry, Amphibole -analyses
DS200812-0028
2008
Anbar, A.D.Anbar, A.D., Gordon, G.W.Redox renaissance.Geology, Vol. 36, 3 March pp. 271-271.TechnologyCarbon cycles
DS201902-0280
2019
Anbar, A.D.Ionov, D.A., Qi, Y-H., Kang, J-T., Golovin, A.V., Oleinikov, O.B., Zheng, W., Anbar, A.D., Zhang, Z-F., Huang, F.Calcium isotopic signatures of carbonatite and silicate metasomatism, melt percolation and crustal recycling in the lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 248, pp. 1-13.Russia, Siberiacarbonatite

Abstract: Ca isotopes can be strongly fractionated at the Earth’s surface and thus may be tracers of subducted carbonates and other Ca-rich surface materials in mantle rocks, magmas and fluids. However, the ?44/40Ca range in the mantle and the scope of intra-mantle isotope fractionation are poorly constrained. We report Ca isotope analyses for 22 mantle xenoliths: four basalt-hosted refractory peridotites from Tariat in Mongolia and 18 samples from the Obnazhennaya (Obn) kimberlite on the NE Siberian craton. Obn peridotites are Paleoproterozoic to Archean melting residues metasomatised by carbonate-rich and/or silicate melts including unique xenoliths that contain texturally equilibrated carbonates. ?44/40Ca in 15 Obn xenoliths shows limited variation (0.74-0.97‰) that overlaps the value (0.94?±?0.05‰) inferred for the bulk silicate Earth from data on fertile lherzolites, but is lower than ?44/40Ca for non-metasomatised refractory peridotites from Mongolia (1.10?±?0.03‰). Bulk ?44/40Ca in four Obn peridotites containing metasomatic carbonates ranges from 0.81?±?0.08‰ to 0.83?±?0.06‰, with similar values in acid-leachates and leaching residues, indicating isotopic equilibration of the carbonates with host rocks. We infer that (a) metasomatism tends to decrease ?44/40Ca values of the mantle, but its effects are usually limited (?0.3‰); (b) Ca isotopes cannot distinguish "carbonatite" and "silicate" types of mantle metasomatism. The lowest ?44/40Ca value (0.56‰) was obtained for a phlogopite-bearing Obn peridotite with a very high Ca/Al of 8 suggesting that the greatest metasomatism-induced Ca isotope shifts may be seen in rocks initially low in Ca that experienced significant Ca input leading to high Ca/Al. Two Obn peridotites, a dunite (melt channel material) and a veined spinel wehrlite, have high ?44/40Ca values (1.22‰ and 1.38‰), which may be due to isotope fractionation by diffusion during silicate melt intrusion and percolation in the host mantle. Overall, we find no evidence that recycling of crustal carbonates may greatly affect Ca isotope values in the global mantle or on a regional scale.
DS201903-0519
2018
Anbar, A.D.Ionov, D.A., Qi, Y-H., Kang, J-T., Golovin, A.V., Oleinikov, O.B., Zheng, W., Anbar, A.D., Zhang, Z-F., Huang, F.Calcium isotopic signatures of carbonatite and silicate metasomatism, melt percolation and crustal recyclying in the lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 248, pp. 1-13.Mantlecarbonatite

Abstract: Ca isotopes can be strongly fractionated at the Earth’s surface and thus may be tracers of subducted carbonates and other Ca-rich surface materials in mantle rocks, magmas and fluids. However, the ?44/40Ca range in the mantle and the scope of intra-mantle isotope fractionation are poorly constrained. We report Ca isotope analyses for 22 mantle xenoliths: four basalt-hosted refractory peridotites from Tariat in Mongolia and 18 samples from the Obnazhennaya (Obn) kimberlite on the NE Siberian craton. Obn peridotites are Paleoproterozoic to Archean melting residues metasomatised by carbonate-rich and/or silicate melts including unique xenoliths that contain texturally equilibrated carbonates. ?44/40Ca in 15 Obn xenoliths shows limited variation (0.74-0.97‰) that overlaps the value (0.94?±?0.05‰) inferred for the bulk silicate Earth from data on fertile lherzolites, but is lower than ?44/40Ca for non-metasomatised refractory peridotites from Mongolia (1.10?±?0.03‰). Bulk ?44/40Ca in four Obn peridotites containing metasomatic carbonates ranges from 0.81?±?0.08‰ to 0.83?±?0.06‰, with similar values in acid-leachates and leaching residues, indicating isotopic equilibration of the carbonates with host rocks. We infer that (a) metasomatism tends to decrease ?44/40Ca values of the mantle, but its effects are usually limited (?0.3‰); (b) Ca isotopes cannot distinguish "carbonatite" and "silicate" types of mantle metasomatism. The lowest ?44/40Ca value (0.56‰) was obtained for a phlogopite-bearing Obn peridotite with a very high Ca/Al of 8 suggesting that the greatest metasomatism-induced Ca isotope shifts may be seen in rocks initially low in Ca that experienced significant Ca input leading to high Ca/Al. Two Obn peridotites, a dunite (melt channel material) and a veined spinel wehrlite, have high ?44/40Ca values (1.22‰ and 1.38‰), which may be due to isotope fractionation by diffusion during silicate melt intrusion and percolation in the host mantle. Overall, we find no evidence that recycling of crustal carbonates may greatly affect Ca isotope values in the global mantle or on a regional scale.
DS201904-0749
2019
Anbar, A.D.Ionov, D.A., Qi, YpH., Kang, J-T., Golovin, A.V., Oleinkov, O.B., Zheng, W., Anbar, A.D., Zhang, Z-F., Huang, F.Calcium isotopic signatures of carbonatite and silicate metasomatism, melt percolation and crustal recycling in the lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 248, pp. 1-13.Mantle, Asia, Mongolia, Russia, Siberiametasomatism

Abstract: Ca isotopes can be strongly fractionated at the Earth’s surface and thus may be tracers of subducted carbonates and other Ca-rich surface materials in mantle rocks, magmas and fluids. However, the ?44/40Ca range in the mantle and the scope of intra-mantle isotope fractionation are poorly constrained. We report Ca isotope analyses for 22 mantle xenoliths: four basalt-hosted refractory peridotites from Tariat in Mongolia and 18 samples from the Obnazhennaya (Obn) kimberlite on the NE Siberian craton. Obn peridotites are Paleoproterozoic to Archean melting residues metasomatised by carbonate-rich and/or silicate melts including unique xenoliths that contain texturally equilibrated carbonates. ?44/40Ca in 15 Obn xenoliths shows limited variation (0.74-0.97‰) that overlaps the value (0.94?±?0.05‰) inferred for the bulk silicate Earth from data on fertile lherzolites, but is lower than ?44/40Ca for non-metasomatised refractory peridotites from Mongolia (1.10?±?0.03‰). Bulk ?44/40Ca in four Obn peridotites containing metasomatic carbonates ranges from 0.81?±?0.08‰ to 0.83?±?0.06‰, with similar values in acid-leachates and leaching residues, indicating isotopic equilibration of the carbonates with host rocks. We infer that (a) metasomatism tends to decrease ?44/40Ca values of the mantle, but its effects are usually limited (?0.3‰); (b) Ca isotopes cannot distinguish “carbonatite” and “silicate” types of mantle metasomatism. The lowest ?44/40Ca value (0.56‰) was obtained for a phlogopite-bearing Obn peridotite with a very high Ca/Al of 8 suggesting that the greatest metasomatism-induced Ca isotope shifts may be seen in rocks initially low in Ca that experienced significant Ca input leading to high Ca/Al. Two Obn peridotites, a dunite (melt channel material) and a veined spinel wehrlite, have high ?44/40Ca values (1.22‰ and 1.38‰), which may be due to isotope fractionation by diffusion during silicate melt intrusion and percolation in the host mantle. Overall, we find no evidence that recycling of crustal carbonates may greatly affect Ca isotope values in the global mantle or on a regional scale.
DS201904-0761
2019
Anbar, A.D.Nicklas, R.W., Puchtel, I.S., Ash, R.D., Piccoli, P.M., Hanski, M., Eero, Nisbet, E.G., Waterton, P., Pearson, D.G., Anbar, A.D.Secular mantle oxidation across the Archean - Proterozoic boundary: evidence from V partitioning in komatiites and picrites.Geochimica et Cosmochimica Acta, Vol. 250, 1, pp. 49-75.Mantlepicrites

Abstract: The oxygen fugacities of nine mantle-derived komatiitic and picritic systems ranging in age from 3.55?Ga to modern day were determined using the redox-sensitive partitioning of V between liquidus olivine and komatiitic/picritic melt. The combined set of the oxygen fugacity data for seven systems from this study and the six komatiite systems studied by Nicklas et al. (2018), all of which likely represent large regions of the mantle, defines a well-constrained trend indicating an increase in oxygen fugacity of the lavas of ?1.3 ?FMQ log units from 3.48 to 1.87?Ga, and a nearly constant oxygen fugacity from 1.87?Ga to the present. The oxygen fugacity data for the 3.55?Ga Schapenburg komatiite system, the mantle source region of which was previously argued to have been isolated from mantle convection within the first 30?Ma of the Solar System history, plot well above the trend and were not included in the regression. These komatiite’s anomalously high oxygen fugacity data likely reflect preservation of early-formed magma ocean redox heterogeneities until at least the Paleoarchean. The observed increase in the oxygen fugacity of the studied komatiite and picrite systems of ?1.3 ?FMQ log units is shown to be a feature of their mantle source regions and is interpreted to indicate secular oxidation of the mantle between 3.48 and 1.87?Ga. Three mechanisms are considered to account for the observed change in the redox state of the mantle: (1) recycling of altered oceanic crust, (2) venting of oxygen from the core due to inner core crystallization, and (3) convection-driven homogenization of an initially redox-heterogeneous primordial mantle. It is demonstrated that none of the three mechanisms alone can fully explain the observed trend, although mechanism (3) is best supported by the available geochemical data. These new data provide further evidence for mantle involvement in the dramatic increase in the oxygen concentration of the atmosphere leading up to the Great Oxidation Event at ?2.4?Ga.
DS202107-1120
2021
Anbar, A.D.Ostrander, C.M., Johnson, A.C., Anbar, A.D.Earth's first redox revolution.Annual Review of Earth and Planetary Sciences, Vol. 49, pp. 337-366.Mantleredox

Abstract: The rise of molecular oxygen (O2) in the atmosphere and oceans was one of the most consequential changes in Earth's history. While most research focuses on the Great Oxidation Event (GOE) near the start of the Proterozoic Eon—after which O2 became irreversibly greater than 0.1% of the atmosphere—many lines of evidence indicate a smaller oxygenation event before this time, at the end of the Archean Eon (2.5 billion years ago). Additional evidence of mild environmental oxidation—probably by O2—is found throughout the Archean. This emerging evidence suggests that the GOE might be best regarded as the climax of a broader First Redox Revolution (FRR) of the Earth system characterized by two or more earlier Archean Oxidation Events (AOEs). Understanding the timing and tempo of this revolution is key to unraveling the drivers of Earth's evolution as an inhabited world—and has implications for the search for life on worlds beyond our own. Many inorganic geochemical proxies suggest that biological O2 production preceded Earth's GOE by perhaps more than 1 billion years. Early O2 accumulation may have been dynamic, with at least two AOEs predating the GOE. If so, the GOE was the climax of an extended period of environmental redox instability. We should broaden our focus to examine and understand the entirety of Earth's FRR.
DS201508-0358
2015
AnbazhaganHe, X-F., Santosh, M., Zhang, Z-M., Tsunogae, T., Chetty, T.R.K., Ram Moham, M., AnbazhaganShonkinites from Salem, southern India: implications for Cryogenian alkaline magmatism in rift related setting.Journal of Asian Earth Sciences, in press availableIndiaShonkinites
DS201509-0426
2015
Ancelmi, M.F.Saraiva dos Santos, T.J., Da Silva Amaral, W., Ancelmi, M.F., Pitarello, M.Z., Fuck, R.A., Dantas, E.L.U-Pb age of coesite bearing eclogite from NW Borborema Province, NE Brazil: implications for western Gondwana assembly.Gondwana Research, Vol. 28, pp. 1183-1196.South America, BrazilUHP

Abstract: The Late Neoproterozoic assembly of western Gondwana played an important role in the subduction of oceanic and continental lithospheres. Such event was also a source of arc magmatism, reworking of cratonic margins and development of ultra-high pressure (UHP) suture zones. In the Borborema province, NE Brazil, we have described for the first time UHP rocks enclosed within gneiss migmatite and calc-silicate rocks. They bear coesite included in atoll-type garnet from metamafic rocks, identified by petrographic study and Raman microspectroscopy analysis. U-Pb zircon dating of the leucosome of the migmatites and the calc-silicate rock displays, concordant ages of 639 ± 10 Ma and 649.7 ± 5 Ma, respectively, here interpreted as the minimum age of the eclogitization event in the region. U-Pb zircon dating of the coesite-bearing rock defined a concordia age of 614. 9 ± 7.9 Ma that comprised the retrograde eclogitic conditions to amphibolite facies. The UHP rocks, mostly retrograded to garnet amphibolites, occur enclosed in the Paleoproterozoic continental block composed of calc-silicate rocks, migmatized sillimanite gneiss, mylonitic augen gneiss and granitic and tonalitic gneiss along a narrow N-S oriented belt between the Santa Quitéria magmatic arc and the Transbrasiliano lineament. This block was involved in the subduction to UHP eclogite depths, and was retrogressed to amphibolite during its exhumation and thrusting. Our data indicate an important Neoproterozoic transcontinental suture zone connecting the Pharusian belt with Borborema Province, and probably with the Brasília belt in central Brazil.
DS2003-0526
2003
Anckar, E.Gurney, J.L., Baumgartner, M., Anckar, E., Gurney, J.J., Nowicki, T.E., GrutterKimberlite almanac8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractSouth AfricaDeposit - Finsch
DS200412-0754
2003
Anckar, E.Gurney, J.L., Baumgartner, M., Anckar, E., Gurney, J.J., Nowicki, T.E., Grutter, H.S., Coetzee, M., Mason-JoneKimberlite almanac.8 IKC Program, Session 8, POSTER abstractAfrica, South AfricaDiamond exploration Deposit - Finsch
DS200412-0911
2004
Anckar, E.Jelsma, H.A., De Wit, M.J., Thiart, C., Dirks, P.H.G.M., Viola, G., Basson, U., Anckar, E.Preferential distribution along transcontinental corridors of kimberlites and related rocks of Southern Africa.South African Journal of Geology, Vol. 107, 1/2, pp. 302-324.Africa, South AfricaTectonics, structures, lineaments
DS200412-2151
2004
Anckar, E.Wyatt, B.A., Baumgartner, M., Anckar, E., Grutter, H.Compositional classification of kimberlitic and non-kimberlitic ilmenite.Lithos, Vol. 77, 1-4, Sept. pp. 819-840.TechnologyPicroilmenite, geikielite, hematite, exploration
DS200512-0373
2005
Anckar, E.Grutter, H.S., Anckar, E.Cr Ca and related characteristics of peridotitic garnets from the central Slave and central Kaapvaal craton roots, with implications - carbon in peridotiteGAC Annual Meeting Halifax May 15-19, Abstract 1p.Canada, Northwest TerritoriesGeochronology, metasomatism
DS2002-0033
2002
Anckar, E.C.Anckar, E.C., Gurney, J.J., Thiarz, C.A statistical approach to finger printing run of mine diamonds incorporating FTIR spectra, size distributions and physical characteristics.Eos, American Geophysical Union, Spring Abstract Volume, Vol.83,19, 1p.South AfricaDiamond - morphology, populations
DS2003-0016
2003
Anckar, E.C.Anckar, E.C., Gurney, J.J., Thiart, C.A statistical approach to finger printing of run of mine diamonds using FTIR Spectra8 Ikc Www.venuewest.com/8ikc/program.htm, Session 3, AbstractGlobalDiamonds, database FTIR 495, Geostatistics - production
DS200412-0032
2003
Anckar, E.C.Anckar, E.C., Gurney, J.J., Thiart, C.A statistical approach to finger printing of run of mine diamonds using FTIR Spectra, size distribution and physical characteris8 IKC Program, Session 3, AbstractTechnologyDiamonds, database FTIR 495 Geostatistics - production
DS1987-0007
1987
Ancochea, E.Ancochea, E., Nixon P.H.Cenoliths in the Iberian Peninsulain: Mantle Xenoliths, editor Nixon, P.H, pp. 119-126GlobalAnalyses p. 120 lherzolites, Analyses p. 124 Amphibole
DS1982-0012
1982
Ancochea, F.Ancochea, F., Ibarrola, E.Geochemical Characteristics of Volcanism in Central Spain.*spaBol. de la Real Soc. Espanola de Historia Natural, *SPA., Section Geologia, Vol. 80, No. 1-4, pp. 57-88GlobalLeucitite, Melilitite, Campos De Calatava
DS201312-0879
2013
and EIMFStachel, T., Harris, J.W., Hunt, L., Muehlenbachs, K., and EIMFDiamonds from the Argyle lamproite ( Western Australia): different from any other mine?GAC-MAC 2013 SS4: Diamond: from birth in the mantle to emplacement in kimberlite, abstract onlyAustraliaDeposit - Argyle
DS1988-0441
1988
and Mariano, A.N.Marshall, D.J., and Mariano, A.N.Cathodoluminescence of geologic materialsUnwin Hyman, Chap. 4, Class I: native elements Diamond pp.37-38, 117GlobalPetrography, Cathodoluminescence
DS1991-1655
1991
and reply Reaban, M.E.Stavnezer, J., and reply Reaban, M.E., Griffiths, J.A.Triple helix stabilizationNature, Vol. 351, No. 6326, June 6, p. 447GlobalStructure, Tectonics
DS1981-0003
1981
Ander, M.E.Aldrich, M.J., Ander, M.E., Laughlin, A.W.Geological and Geophysical Signatures of the Jemez Lineament: a Reactivated Precambrian Structure.National Technical Information Service LA-UR-82-561, Conference 8L0887-2, DE82011971, 35P.GlobalMid-continent, Tectonic
DS201606-1117
2016
Anderko, A.Shivaramaiah, R., Anderko, A., Riman, R.E., Navrotsky, A.Thermodynamics of Bastnaesite: a major rare earth mineral.American Mineralogist, Vol. 101, 5, pp. 1129-1134.TechnologyBastanesite

Abstract: Bastnaesite, [RE-CO3-OH/F] (RE = rare earth) is one of the major sources of rare earth elements found in commercial deposits at Mountain Pass, California, Bayan Obo, China, and elsewhere. Synthetic forms of bastnaesite have been explored for applications including optical devices and phosphors. Determination of thermodynamic properties of these phases is critical for understanding their origin, mining, and processing. We report the first experimental determination of formation enthalpies of several OH and F bastnaesites based on high-temperature oxide melt solution calorimetry of well-characterized synthetic samples. The formation enthalpies from binary oxides and fluorides for all the bastnaesite samples are highly exothermic, consistent with their stability in the garnet zone of the Earth’s crust. Fluoride bastnaesite, which is more abundant in nature than its hydroxide counterpart, is thermodynamically more stable. For both OH and F bastnaesite, the enthalpy of formation becomes more negative with increasing ionic radius of the RE3+ cation. This periodic trend is also observed among rare earth phosphates and several other rare earth ternary oxides. For a given RE, the formation enthalpies from binary oxides are more negative for orthophosphates than for bastnaesites, supporting the argument that monazite could have formed by reaction of bastnaesite and apatite at high temperature. The difference in formation enthalpy of monazite and bastnaesite provides insight into energetics of such reactions along the rare earth series.
DS1960-0511
1965
Anders, E.Anders, E.Diamonds in Meteorites. #3Scientific American., Vol. 213, JULY-Dec. PP. 26-36.United States, Arizona, Colorado PlateauBlank
DS1987-0413
1987
Anders, E.Lewis, R.S., Ming, T., Wacker, J.F., Anders, E., Steel, E.Interstellar diamonds in meteoritesNature, Vol. 326, No. 6109, March 12, pp. 160-161GlobalMeteorites
DS1988-0682
1988
Anders, E.Tang Ming, Anders, E.Isotopic anomalies of Neodynium, Xenon, and Carbon in meteorites:II. Interstellar diamond and SiC: carriers of exotic noblegases.see also pts. 1, 2. sGeochimica et Cosmochimica Acta, Vol. 52, No. 5, May pp. 1235-1244Globalmeteorites, carbon, xenon
DS1990-0116
1990
Anders, E.Amari, S., Anders, E., Virag, A.Interstellar graphite in meteoritesNature, Vol. 345, No. 6272, May 17, p. 238-239GlobalMeteorites, Graphite
DS1990-0928
1990
Anders, E.Lewis, R.S., Amari, S., Anders, E.Meteoritic silicon carbide: pristine material from carbon starsNature, Vol. 348, No. 6299, November 22, pp. 293-297GlobalMeteorites, Petrology
DS1989-0001
1989
Anders, M.Abbott, D., Anders, M.Identifying Precambrian hotspots: the Limpopo beltEos, Vol. 70, No. 43, October 24, p. 1357. AbstractSouthern AfricaBeitbridge, Diamonds
DS1993-0326
1993
Anders, M.H.Dawers, N.., Anders, M.H., Schola, C.H.Growth of normal faults: displacement length scalingGeology, Vol. 21, No. 12, December pp. 1107-1110CaliforniaBishop Tuff, Structure
DS1994-0045
1994
Anders, M.H.Anders, M.H.Constraints on North American plate velocity from the Yellowstone hotspot deformation fieldNature, Vol. 369, May 5, pp. 53-55IdahoHotspot, Tectonics
DS1994-0046
1994
Anders, M.H.Anders, M.H., Schlische, R.W.Overlapping faults, intrabasin highs and the growth of normal faultsJournal of Geology, Vol. 102, No. 2, March pp. 165-180Basin and RangeStructure, Fault systems
DS2002-0034
2002
Anders, M.H.Anders, M.H., Gregory-Wodzicki, K.M., Spiegelman, M.A critical evaluation of Late Tertiary accelerated uplift rates for the eastern Cordillera, central AndesJournal of Geology, Vol.110,1,pp. 89-100.BoliviaTectonics
DS1995-0201
1995
AndersenBrandl, G., McCarthy, T.S., Andreoli, M.A.G., AndersenTectonic and lineament investigations of the Vaalputs area, Namaqualand, South Africa: implications rifting..Centennial Geocongress (1995) Extended abstracts, Vol. 1, p. 445-448. abstractSouth AfricaTectonics
DS1995-1338
1995
AndersenNeumann, E.R., Wulff-Pedersen, E., Johnsen, K., AndersenPetrogenesis of spinel harzburgite and dunite suite xenoliths fromLanzarote, eastern Canary Islands.Lithos, Vol. 35, No. 1-2, April pp. 83-108.GlobalMantle, Xenoliths
DS2000-0105
2000
AndersenBraathen, A., Nordgulen, Osmundsen, Andersen, SolliDevonian, orogen parallel, opposed extension in the central Norwegian Caledonides.Geology, Vol. 28, No. 7, July, pp. 615-18.NorwayBaltica, Laurentia, Tectonics
DS200512-0014
1998
Andersen, A.C.Andersen, A.C., Jorgensen, U.G., Nicolaisen, F.M., Sorensen, P.G., Glejbal, K.Spectral features of presolar diamonds in laboratory and in carbon star atmospheres.Astronomy and Astrophysics, Vol. 330, pp. 1080-1090.Meteorite
DS201608-1388
2016
Andersen, A.K.Andersen, A.K., Clar, J.G., Larson, P.B., Neill, O.K.Mineral chemistry and petrogenesis of a HFSE(+HREE) occurrence, peripheral to carbonatites of the Bear Lodge alkaline complex, Wyoming.American Mineralogist, Vol. 101, pp. 1604-1623.United States, Wyoming, Colorado PlateauBear Lodge

Abstract: Rare earth mineralization in the Bear Lodge alkaline complex (BLAC) is mainly associated with an anastomosing network of carbonatite dikes and veins, and their oxidized equivalents. Bear Lodge carbonatites are LREE-dominant, with some peripheral zones enriched in HREEs. We describe the unique chemistry and mineralogy one such peripheral zone, the Cole HFSE(+HREE) Occurrence (CHO), located ~2 km from the main carbonatite intrusions. The CHO consists of anatase, xenotime-(Y), brockite, fluorite, zircon, and K-feldspar, and contains up to 44.88% TiO2, 3.12% Nb2O5, 6.52% Y2O3, 0.80% Dy2O3, 2.63% ThO2, 6.0% P2O5, and 3.73% F. Electron microprobe analyses of xenotime-(Y) overgrowths on zircon show that oscillatory zoning is a result of variable Th and Ca content. Cheralite-type substitution, whereby Th and Ca are incorporated at the expense of REEs, is predominant over the more commonly observed thorite-type substitution in xenotime-(Y). Th/Ca-rich domains are highly beam sensitive and accompanied by high-F concentrations and low-microprobe oxide totals, suggesting cheralite-type substitution is more easily accommodated in fluorinated and hydrated/hydroxylated xenotime-(Y). Analyses of xenotime-(Y) and brockite show evidence of Embedded Image substitution for Embedded Image with patches of an undefined Ca-Th-Y-Ln phosphovanadate solid-solution composition within brockite clusters. Fluorite from the CHO is HREE-enriched with an average Y/Ho ratio of 33.2, while other generations of fluorite throughout the BLAC are LREE-enriched with Y/Ho ratios of 58.6-102.5. HFSE(+HREE) mineralization occurs at the interface between alkaline silicate intrusions and the first outward occurrence of calcareous Paleozoic sedimentary rocks, which may be local sources of P, Ti, V, Zr, and Y. U-Pb zircon ages determined by LA-ICP-MS reveal two definitive 207Pb/206Pb populations at 2.60-2.75 and 1.83-1.88 Ga, consistent with derivation from adjacent sandstones and Archean granite. Therefore, Zr and Hf are concentrated by a physical process independent of the Ti/Nb-enriched fluid composition responsible for anatase crystallization. The CHO exemplifies the extreme fluid compositions possible after protracted LREE-rich crystal fractionation and subsequent fluid exsolution in carbonatite-fluid systems. We suggest that the anatase+xenotime-(Y)+brockite+fluorite assemblage precipitated from highly fractionated, low-temperature (<200 °C), F-rich fluids temporally related to carbonatite emplacement, but after significant fractionation of ancylite and Ca-REE fluorocarbonates. Low-temperature aqueous conditions are supported by the presence of fine-grained anatase as the sole Ti-oxide mineral, concentrically banded botryoidal fluorite textures, and presumed hydration of phosphate minerals. Fluid interaction with Ca-rich lithologies is known to initiate fluorite crystallization which may cause destabilization of (HREE,Ti,Nb)-fluoride complexes and precipitation of REE+Th phosphates and Nb-anatase, a model valuable to the exploration for economic concentrations of HREEs, Ti, and Nb.
DS201709-1951
2017
Andersen, A.K.Andersen, A.K., Clark, J.G., Larson, P.B., Donovan, J.J.REE fractionation, mineral speciation, and supergene enrichment of the Bear Lodge carbonatites, Wyoming, USA.Ore Geology Reviews, Vol. 89, pp. 780-807.United States, Wyomingcarbonatite - Bear Lodge

Abstract: The Eocene (ca. 55–38 Ma) Bear Lodge alkaline complex in the northern Black Hills region of northeastern Wyoming (USA) is host to stockwork-style carbonatite dikes and veins with high concentrations of rare earth elements (e.g., La: 4140–21000 ppm, Ce: 9220–35800 ppm, Nd: 4800–13900 ppm). The central carbonatite dike swarm is characterized by zones of variable REE content, with peripheral zones enriched in HREE including yttrium. The principle REE-bearing phases in unoxidized carbonatite are ancylite and carbocernaite, with subordinate monazite, fluorapatite, burbankite, and Ca-REE fluorocarbonates. In oxidized carbonatite, REE are hosted primarily by Ca-REE fluorocarbonates (bastnäsite, parisite, synchysite, and mixed varieties), with lesser REE phosphates (rhabdophane and monazite), fluorapatite, and cerianite. REE abundances were substantially upgraded (e.g., La: 54500–66800 ppm, Ce: 11500–92100 ppm, Nd: 4740–31200 ppm) in carbonatite that was altered by oxidizing hydrothermal and supergene processes. Vertical, near surface increases in REE concentrations correlate with replacement of REE(±Sr,Ca,Na,Ba) carbonate minerals by Ca-REE fluorocarbonate minerals, dissolution of matrix calcite, development of Fe- and Mn-rich gossan, crystallization of cerianite and accompanying negative Ce anomalies in secondary fluorocarbonates and phosphates, and increasing ?18O values. These vertical changes demonstrate the importance of oxidizing meteoric water during the most recent modifications to the carbonatite stockwork. Scanning electron microscopy, energy dispersive spectroscopy, and electron probe microanalysis were used to investigate variations in mineral chemistry controlling the lateral complex-wide geochemical heterogeneity. HREE-enrichment in some peripheral zones can be attributed to an increase in the abundance of secondary REE phosphates (rhabdophane group, monazite, and fluorapatite), while HREE-enrichment in other zones is a result of HREE substitution in the otherwise LREE-selective fluorocarbonate minerals. Microprobe analyses show that HREE substitution is most pronounced in Ca-rich fluorocarbonates (parisite, synchysite, and mixed syntaxial varieties). Peripheral, late-stage HREE-enrichment is attributed to: 1) fractionation during early crystallization of LREE selective minerals, such as ancylite, carbocernaite, and Ca-REE fluorocarbonates in the central Bull Hill dike swarm, 2) REE liberated during breakdown of primary calcite and apatite with higher HREE/LREE ratios, and 3) differential transport of REE in fluids with higher PO43?/CO32? and F?/CO32? ratios, leading to phosphate and pseudomorphic fluorocarbonate mineralization. Supergene weathering processes were important at the stratigraphically highest peripheral REE occurrence, which consists of fine, acicular monazite, jarosite, rutile/pseudorutile, barite, and plumbopyrochlore, an assemblage mineralogically similar to carbonatite laterites in tropical regions.
DS2000-0774
2000
Andersen, J.C.O.Power, M.R., Pirrie, D., Andersen, J.C.O., Wheeler, P.D.Testing the validity of chrome spinel chemistry as a provenance and petrogenetic indicator.Geology, Vol. 28, No. 1, Nov. pp. 1027-30.ScotlandLayered intrusion - RuM., Mineral chemistry - spinels ( not specific to diamonds
DS1995-0839
1995
Andersen, K.M.Ihinger, P.D., Andersen, K.M.A plumlet model for the generation of New England lamprophyresGeological Society of America (GSA) Abstracts, Vol. 27, No. 1, Feb. p. 57.GlobalLamprophyres
DS1989-1491
1989
Andersen, L.S.Tembo, F., Andersen, L.S., Sliwa, A., Turner, D.C.The Chilembwe phosphate deposits, Zambia: remobilized apatite cumulated in a syenite intrusionZimco, MINEX seminar on Carbonatites and other igneous phosphate bearing, Held Feb. 1, 1989, 1pZambiaSyenite-phosphate
DS201312-0743
2013
Andersen, M.B.Richards, D.A., Andersen, M.B.Time constraints and tie-points in the Quaternary period.Elements, Vol. 9, pp. 45-51.TechnologyGeochronology - radioisotope
DS201908-1768
2019
Andersen, N.Alberti, M., Arabas, A., Fursich, F.T., Andersen, N., Ziolkowski, P.The Middle to Upper Jurassic stable isotope record of Madagascar: linking temperature changes with plate tectonics during the break-up of Gondwana.Gondwana Research, Vol. 73, pp. 1-15.Africa, Madagascargeochemistry

Abstract: Stable isotope (?18O, ?13C) analyses were performed on well preserved belemnites, oysters, and rhynchonellid brachiopods from the Middle to Upper Jurassic of the Morondava Basin in southern Madagascar. Both brachiopods and oysters indicate similar average temperatures of 18.7 to 19.3?°C in the Early Callovian, followed by a temperature decrease towards the Middle Oxfordian (13.9?°C) and a minimum in the Early Kimmeridgian (12.3?°C). In contrast, belemnites from the Oxfordian show lower average temperatures of 10.0?°C, which is likely caused by specific conditions for these organisms (e.g., different fractionation or life habits). Additionally, three oysters from the Upper Oxfordian and Lower Kimmeridgian were used for high-resolution stable isotope analyses. The data show seasonal fluctuations of >6?°C around averages between 14.4 and 14.7?°C. Latitudinal temperature gradients for the Callovian and Kimmeridgian are similar to today at the examined low latitudes of the southern hemisphere. The observed cooling of around 5?°C from the Callovian to the Oxfordian/Kimmeridgian can be attributed to a concurrent southward drift of Madagascar during the break-up of Gondwana. Thus, the study underlines the importance of considering palaeogeography in interpreting stable isotope data as well as the potential of detecting and timing palaeogeographic events by using stable isotope analyses.
DS1984-0011
1984
Andersen, T.Andersen, T.Secondary Processes in Carbonatites- Petrology of Rooberg (hematite calcite Dolomite Carbonatite in the Fen Central Complex) Telemark South Norway.Lithos, Vol. 17, No. 3, PP. 227-245.Norway, ScandinaviaCarbonatite, Fen
DS1984-0012
1984
Andersen, T.Andersen, T., O'reilly, S.Y., Griffin, W.L.The Trapped Fluid Phase in Upper Mantle Xenoliths from Victoria, Australia: Implications for Mantle MetasomatismContributions to Mineralogy and Petrology, Vol. 88, PP. 72-85.Australia, South AustraliaPetrography, Inclusions, Microthermometry, Metasomatism
DS1986-0019
1986
Andersen, T.Andersen, T.Compositional variation of some rare earth minerals from the Fen Complex (Telemark, southeast Norway)- implications for the mobilityof rare earths in a carbonatite systeMineralogical Magazine, Vol. 50, Sept. pp. 503-509NorwayCarbonatite, rare earth elements (REE)
DS1986-0020
1986
Andersen, T.Andersen, T.Compositional variation of some rare earth minerals from the Fen complex(telemark, southeast Norway): implications for the mobility of rare earths in a carbonatite systemMineralogical Magazine, Vol. 50, No. 357, September pp. 503-509NorwayRare Earths, Carbonatite
DS1986-0021
1986
Andersen, T.Andersen, T., Qvale, H.Pyroclastic mechanisms for carbonatite intrusion- evidence from intrusives in the Fen central complex, southeast Norway. (Technicalnote)Journal of Geology, Vol. 94, No. 5, September pp. 762-769NorwayRare Earths, Carbonatite
DS1987-0008
1987
Andersen, T.Andersen, T.Mantle and crustal components in a carbonatite complex and the evolution of carbonatite magma: rare earth elements (REE) and isotopic evidence from the Fen complex, southeast NorwayChemical Geology, Vol. 65, No. 2, May 15, pp. 147-166NorwayCarbonatite, Fen complex
DS1988-0010
1988
Andersen, T.Andersen, T.Evolution of peralkaline calcite carbonatite magma In the Fen Complex, southeast NorwayLithos, Vol. 22, No. 2, December pp. 99-112NorwayCarbonatite
DS1989-0023
1989
Andersen, T.Andersen, T.Carbonatite-related contact metasomatism in the FenComplex, Norway-effects and petrogenetic implicationsMineralogical Magazine, Vol. 53, No. 372, September pp. 395-414NorwayCarbonatite, Metasomatism
DS1991-0023
1991
Andersen, T.Andersen, T., Austrhei, H.Temperature Hafnium fugacity trends during crystallization of calcite carbonatite magma in the Fen Complex, NorwayMineralogical Magazine, Vol. 55, No. 378, March pp. 81-94NorwayCarbonatite, Fen Complex
DS1993-0030
1993
Andersen, T.Andersen, T., Sorensen, H.Crystallization and metasomatism of nepheline syenite xenoliths in quartz bearing intrusive rocks in the Permian Oslo rift, southeast Norway.Norsk Geologisk Tidskrift, Vol. 73, pp. 250-266.NorwayXenoliths
DS1995-0035
1995
Andersen, T.Andersen, T., Sundvoll, B.Neodynium isotope systematics of mantle beneath the Baltic Shield: evidence for depleted mantle ArcheanLithos, Vol. 35, pp. 235-243.Baltic ShieldGeochronology, Archean mantle
DS1995-0036
1995
Andersen, T.Andersen, T., Sundvoll, B.Neodynium isotope systematics of the mantle beneath the Baltic shield:evidence for depleted mantle -ArcheanLithos, Vol. 35, No. 3-4, June pp. 235-244Baltic ShieldMantle, Geochronology
DS1997-0027
1997
Andersen, T.Andersen, T.Age and petrogenesis of the Qassiarsuk carbonatite - alkaline silicate volcanic complex in the Gardar rift.Mineralogical Magazine, No. 407, August pp. 499-514.Greenland, south GreenlandCarbonatite
DS1997-0609
1997
Andersen, T.Knudsen, T.L., Andersen, T., Vestin, J.Detrital zircon ages from southern Norway - implications for the Proterozoic evolution of southwest BalticContributions to Mineralogy and Petrology, Vol. 130, No. 1, pp. 47-58.NorwayGeochronology - zircon, Tectonics Baltic shield
DS1999-0370
1999
Andersen, T.Knudsen, T.L., Andersen, T.Petrology and geochemistry of the Tromoy Gneiss Complex, an alleged exampleof Proterozoic depleted...Journal of Petrology, Vol. 40, No. 6, June, pp. 909-34.NorwayLower continental crust
DS2000-0019
2000
Andersen, T.Andersen, T., Knudsen, T-L.Crustal contaminants in the Permian Oslo Rift, South Norway: constraints from Precambrian geochemistry.Lithos, Vol. 53, No. 3-4, Sept. 1, pp. 247-64.Norway, South NorwayTectonics - Oslo Rift, Geochemistry, Geochemistry - bulk earth
DS2002-0035
2002
Andersen, T.Andersen, T., Griffin, W.L., Pearson, N.J.Crustal evolution in the southwest part of the Baltic Shield: the Hf isotope evidenceJournal of Petrology, Vol. 43, 9, Sept.pp. 1725-48.Baltic Shield, NorwayTectonics, Geochronology
DS2002-0482
2002
Andersen, T.Frezzotti, M.L., Andersen, T., Neumann, E.R., Simonsen, S.L.Carbonatite melt CO2 fluid inclusions in mantle xenoliths from Tenerife, Canary Islands:Lithos, Vol. 64, 3-4, pp. 77-96.Mantle, Canary IslandsCarbonatite
DS200412-0033
2004
Andersen, T.Andersen, T., Griffin, W.L.Lu Hf and U Pb isotope systematics of zircons from the Storgangen intrusion, Rogaland Intrusive Complex, SW Norway: implicationsLithos, Vol. 73, 3-4, April pp. 271-288.Europe, NorwayGeochronology, lower crust
DS200412-0034
2004
Andersen, T.Andersen, T., Griffin, W.L., Jackson, S.E., Knudsen, T.L., Pearson, N.J.Mid-Proterozoic magmatic arc evolution at the southwest margin of the Baltic Shield.Lithos, Vol. 73, 3-4, April pp. 289-318.Europe, Norway, Baltic ShieldMagmatism, Laser ablation, geochronology
DS200512-0015
2005
Andersen, T.Andersen, T.Detrital zircons as tracers of sedimentary provenance: limiting conditions from statistics and numerical simulation.Chemical Geology, Vol. 216, 3-4, March 25, pp. 249-270.Clastic sediments, statistics, Monte Carlo, geochronology
DS200612-0073
2006
Andersen, T.Bailey, J.C., Sorensen, H., Andersen, T., Kogarko, L.N., Rose-Hansen, J.On the origin of microrhythmic layering in arfvedsonite lujavrite from the Ilimaussaq alkaline complex, South Greenland.Lithos, in press availableEurope, GreenlandAlkalic
DS200812-0029
2008
Andersen, T.Andersen, T.Coexisting silicate and carbonatitic magmas in the Qassiarsuk Complex, Gardar Rift, southwest Greenland.Canadian Mineralogist, Vol. 46, 4, August pp.Europe, GreenlandCarbonatite
DS200812-0874
2008
Andersen, T.Pedersen, S., Andersen, T., Konnerup-Madsen, J., Griffin, W.L.Recurrent mesoproterozoic continental magmatism in south central Norway.International Journal of Earth Sciences, In press availableEurope, NorwayMagmatism
DS201112-0016
2011
Andersen, T.Andersen, T.Alkalis, water, halogens and the HFSE mineralogy of peralkaline rocks. Oslo RiftPeralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.1-2.Europe, NorwayMineralogical definition
DS201112-0017
2011
Andersen, T.Andersen, T.Alkalis, water, halogens and the HFSE mineralogy of peralkaline rocks. Oslo RiftPeralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.1-2.Europe, NorwayMineralogical definition
DS201112-0018
2011
Andersen, T.Andersen, T.Alkalis, water, halogens and HFSE mineralogy of peralkaline rocks.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, AbstractMineralogy
DS201212-0015
2012
Andersen, T.Andersen, T., Elburg, M., Erambert, M.Petrology of combeite and gotzenite bearing nephelinite at Nyiragongo Virunga volcanic province on the East African rift.Lithos, Vol. 152, pp. 105-121.Africa, TanzaniaNephelinite
DS201412-0299
2014
Andersen, T.Glorie, S., Zhimulev, F.I., Buslov, M.M., Andersen, T., Plavsa, D., Izmer, A., Vanhaecke, F., De Grave, J.Formation of the Kokchetav subduction collision zone - northern Kazakhstan : insights from zircon U-Pb and Lu-Hf isotope systematics.Gondwana Research, Vol. 27, pp. 424-438.Russia, KazakhstanSubduction
DS201412-0315
2014
Andersen, T.Griffin, W.L., Pearson, N.J., Andersen, T., Jackson, S.E., O'Reilly, S.Y., Zhang, M.Sources of cratonic metasomatic fluids: In-situ LA-MC-ICPMS analysis of Sr, Nd and Pb isotopes in Lima from the Jagersfontein kimberlite.American Journal of Science, Vol. 314, pp. 435-461.Africa, South AfricaDeposit - Jagersfontein
DS201604-0594
2016
Andersen, T.Borst, A.M., Friis, H., Andersen, T., Nielsen, T.F.D., Waight, T.E., Smit, M.A.Zirconosilicates in the kakortokites of the Ilmmaussaq complex, South Greenland: implications for fluid evolution and high field strength and rare earth element mineralization in agpaitic systems.Mineralogical Magazine, Vol. 80, 1, pp. 5-30.Europe, GreenlandRare earths

Abstract: The layered agpaitic nepheline syenites (kakortokites) of the Ilímaussaq complex, South Greenland, host voluminous accumulations of eudialyte-group minerals (EGM). These complex Na-Ca-zirconosilicates contain economically attractive levels of Zr, Nb and rare-earth elements (REE), but have commonly undergone extensive autometasomatic/hydrothermal alteration to a variety of secondary mineral assemblages. Three EGM alteration assemblages are recognized, characterized by the secondary zirconosilicates catapleiite, zircon and gittinsite. Theoretical petrogenetic grid models are constructed to assess mineral stabilities in terms of component activities in the late-stage melts and fluids. Widespread alteration of EGM to catapleiite records an overall increase in water activity, and reflects interaction of EGM with late-magmatic Na-, Cl- and F-rich aqueous fluids at the final stages of kakortokite crystallization. Localized alteration of EGM and catapleiite to the rare Ca-Zr silicate gittinsite, previously unidentified at Ilímaussaq, requires an increase in CaO activity and suggests post-magmatic interaction with Ca-Sr bearing aqueous fluids. The pseudomorphic replacement of EGM in the kakortokites was not found to be associated with significant remobilization of the primary Zr, Nb and REE mineralization, regardless of the high concentrations of potential transporting ligands such as F and Cl. We infer that the immobile behaviour essentially reflects the neutral to basic character of the late-magmatic fluids, in which REE-F compounds are insoluble and remobilization of REE as Cl complexes is inhibited by precipitation of nacareniobsite-(Ce) and various Ca-REE silicates. A subsequent decrease in F- activity would furthermore restrict the mobility of Zr as hydroxyl-fluoride complexes, and promote precipitation of the secondary zirconosilicates within the confines of the replaced EGM domains.
DS201609-1697
2016
Andersen, T.Andersen, T., Kristoffersen, M., Elburg, M.A.How far can we trust provenance and crustal evolution information from detrital zircons? A South African case study.Gondwana Research, Vol. 34, pp. 129-148.Africa, South AfricaGeochronology

Abstract: U-Pb and Lu-Hf data are routinely used to trace detrital zircon in clastic sediments to their original source in crystalline bedrock (the protosource), to map out paths of sediment transport, and characterize large-scale processes of crustal evolution. For such data to have a provenance significance, a simple transport route from the protosource in which the zircon formed to its final site of deposition is needed. However, detrital zircon data from Phanerozoic sedimentary cover sequences in South Africa suggest that this “source to sink” relationship has been obscured by repeated events of sedimentary recycling. Phanerozoic sandstones (Cape Supergroup, Karoo Supergroup, Natal Group, Msikaba Formation) and unconsolidated, Cenozoic sands in South Africa share major detrital zircon fractions of late Mesoproterozoic (940-1120 Ma, ?Hf ? 0 to + 15) and Neoproterozoic age (470-720 Ma, ?Hf ? ? 10 to + 8). A Permian age fraction (240-280 Ma, ?Hf ? ? 8 to + 5) is prominent in sandstones from the upper part of the Karoo Supergroup. All of these sequences are dominated by material derived by recycling of older sedimentary rocks, and only the youngest, late Palaeozoic fraction has a clear provenance significance (Gondwanide orogen). The virtual absence of Archaean zircon is a striking feature in nearly all suites of detrital zircon studied in the region. This indicates that significant events in the crustal evolution history of southern African and western Gondwana are not represented in the detrital zircon record. South Africa provides us with a record of recycling of cover sequences throughout the Phanerozoic, and probably back into the Neoproterozoic, in which the “sink” of one sedimentary cycle will act as the “source” in subsequent cycles. In such a setting, detrital zircon may give information on sedimentary processes rather than on provenance.
DS201610-1839
2016
Andersen, T.Andersen, T., Elburg, M., Erambert, M.The miaskitic to agpaitic transition in peralkaline nepheline syenite ( white foyaite) from the Pilanesberg Complex, South Africa.Chemical Geology, in press available 16p.Africa, South AfricaPeralkaline rocks

Abstract: The Mesoproterozoic Pilanesberg Complex, South Africa, is built up by several distinct, ring-shaped intrusions of syenite and peralkaline nepheline syenite. A mildly peralkaline ((Na + K) / Al = 1.04–1.09), medium-to coarse grained nepheline syenite makes up the outermost ring in the southwestern part of the complex (“Matooster type white foyaite”). In this rock, mafic silicate minerals (amphibole, biotite, aegirine) and Ti-bearing minerals (ilmenite, astrophyllite, aenigmatite, lorenzenite, bafertisite, jinshajiangite) are interstitial to feldspar and nepheline, and define a series of mineral assemblages reflecting a change from a miaskitic crystallization regime (with Na-Ca amphibole, titanite and ilmenite) to increasingly agpaitic conditions (with arfvedsonite, aegirine, astrophyllite, aenigmatite, lorenzenite). The main driving force behind the evolution was an increase in peralkalinity of the trapped liquid, mainly by adcumulus growth of alkali feldspar and nepheline, which in the later stages of evolution was combined with increases in oxygen fugacity and water activity. Unlike in most other agpaitic rock complexes, Zr remained compatible in aegirine (and to some extent in amphibole) almost to the end of the process, when a hydrous zirconium silicate mineral (hilairite) crystallized as the only mineral in the rock having essential zirconium. The presence of minerals such as hilairite, bafertisite, jinshajiangite and a Na-REE-Sr rich apatite group mineral (fluorcaphite ?) in the latest assemblages suggests that the last remaining interstitial melt or fluid approached a hyperagpaitic composition. The isolated melt pockets in the Pilanesberg white foyaite follow a pattern of evolution that can be seen as a miniature analogue of the fractional crystallization processes controlling magma evolution in large, alkaline igneous rock complexes.-
DS201707-1304
2017
Andersen, T.Andersen, T., Elburg, M., Erambert, M.The miaskitic to agpaitic transition in peralkaline nepheline syenite ( white foyaite) from the Pelanesberg complex, South Africa.Chemical Geology, Vol. 455, pp. 166-181.Africa, South Africaalkaline rocks

Abstract: The Mesoproterozoic Pilanesberg Complex, South Africa, is built up by several distinct, ring-shaped intrusions of syenite and peralkaline nepheline syenite. A mildly peralkaline ((Na + K) / Al = 1.04–1.09), medium-to coarse grained nepheline syenite makes up the outermost ring in the southwestern part of the complex (“Matooster type white foyaite”). In this rock, mafic silicate minerals (amphibole, biotite, aegirine) and Ti-bearing minerals (ilmenite, astrophyllite, aenigmatite, lorenzenite, bafertisite, jinshajiangite) are interstitial to feldspar and nepheline, and define a series of mineral assemblages reflecting a change from a miaskitic crystallization regime (with Na-Ca amphibole, titanite and ilmenite) to increasingly agpaitic conditions (with arfvedsonite, aegirine, astrophyllite, aenigmatite, lorenzenite). The main driving force behind the evolution was an increase in peralkalinity of the trapped liquid, mainly by adcumulus growth of alkali feldspar and nepheline, which in the later stages of evolution was combined with increases in oxygen fugacity and water activity. Unlike in most other agpaitic rock complexes, Zr remained compatible in aegirine (and to some extent in amphibole) almost to the end of the process, when a hydrous zirconium silicate mineral (hilairite) crystallized as the only mineral in the rock having essential zirconium. The presence of minerals such as hilairite, bafertisite, jinshajiangite and a Na-REE-Sr rich apatite group mineral (fluorcaphite ?) in the latest assemblages suggests that the last remaining interstitial melt or fluid approached a hyperagpaitic composition. The isolated melt pockets in the Pilanesberg white foyaite follow a pattern of evolution that can be seen as a miniature analogue of the fractional crystallization processes controlling magma evolution in large, alkaline igneous rock complexes.
DS201709-1982
2017
Andersen, T.Elburg, M.A., Andersen, T., Mahlaku, S.M., Cawthorn, R.G., Kramers, J.A potassic magma series in the Pilanesberg alkaline complex.Goldschmidt Conference, abstract 1p.Africa, South Africaalkaline rocks

Abstract: The Pilanesberg Alkaline Complex (South Africa) consists of a partially eroded phonolitic-trachytic package of lavas and tuffs, intruded by consanguinous syenites and nepheline syenites (foyaites). The latter have been divided in several units, based on their colour and mineralogy. Most of the foyaitic units are sodic in composition, but whole rock analyses show that some samples are more potassic, with Na2O/K2O<0.8. This observation, together with old reports of leucite-bearing lavas [1], could suggest the existence of a second, potassic magmatic lineage. To investigate whether the observed potassium-enrichment is a primary feature, or the result of deuteric alteration, the mineralogical distinction between sodic and potassic samples was investigated. The mineralogy of the sodic samples is dominated by nepheline, alkali-feldspar and aegirine, ± titanite, amphibole, biotite, and late agpaitic phases [2]. Within the potassic samples, the main primary ferromagnesian mineral is biotite, which shows conspicuous zoning in thin section; nepheline has been extensively replaced by sodalite and cancrinite, but alkali-feldspar appears relatively unaltered. No agpaitic minerals were observed. U-Pb isotope systematics of titanite are similar for sodic and potassic samples in terms of the age (ca. 1.4 Ga) and composion of common Pb; Ar-Ar dating of biotite also gives ca. 1.4 Ga, showing that biotite is a primary magmatic phase. Compositions of the biotite in sodic and potassic samples are similar, with the sodic samples having slightly higher Fe# (independent of whole rock Fe#), higher Na, but lower (Na+K) and Ba. Zoning in biotite from potassic samples is related to a decrease in Mg, Ti and F in the rim of the crystals. Despite the primary character of the biotite, the question whether the potassic samples reflect a combination of alteration and perhaps minor crustal contamination, or a separate mag
DS1991-0024
1991
Andersen, T.B.Andersen, T.B., Jamveit, B., Dewey, J.F., Swensson, E.Subduction and education of continental crust: major mechanisms during continent-continent collision and orogenic extensional collapse, a model Based on NorwegTerra Nova, Vol. 3, No. 3, pp. 303-310NorwayTectonics, Caledonides
DS2000-0375
2000
Andersen, T.B.Hacker, B.R., Andersen, T.B., Vasquez, A.M., Root, D.B.Exhumation of Norwegian ultra high pressure (UHP) eclogites: II. Plutonism and extension beneath the Solund Basin.Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-32.NorwayEclogites, Subduction - slab
DS200512-0293
2005
Andersen, T.B.Foreman, R., Andersen, T.B., Wheeler, J.Eclogite facies polyphase deformation of the Drosdal eclogite, Western Gneiss Complex, Norway, and implications for exhumation.Tectonophysics, Vol. 398, 1-2, March 30, pp. 1-32.Europe, NorwayTectonics, eclogites, not specific to diamonds
DS200512-0485
2005
Andersen, T.B.Jolivet, L., Raimbourg, H., Labrousse, L., Avigad, D., Leroy, Y., Austrheim, H., Andersen, T.B.Softening triggered by eclogitization, the first step toward exhumation during continental subduction.Earth and Planetary Science Letters, Vol. 237, 3-4, Sept. 15, pp. 532-547.Europe, NorwayEclogite, subduction
DS201212-0173
2012
Andersen, T.B.Duretz, T., Gerya, T.V., Kaus, B.J.P., Andersen, T.B.Thermomechanical modeling of slab eduction.Journal of Geophysical Research, Vol. 117, B08411 17p.MantlePlate tectonics - subduction
DS1987-0009
1987
Andersen, Y.Andersen, Y., Griffin, W.L., O'Reilly, S.Y.Primary sulphide melt inclusions in mantle derived megacrystsandpyroxenitesLithos, Vol. 20, No. 4, July pp. 279-294Australia, NorwayBlank
DS2001-0023
2001
Andersen. T.Andersen. T., Neumann, E-R.Fluid inclusions in xenolithsLithos, Vol. 55, No.1-4, Jan. pp. 301-20.MantleXenoliths, olivine, pyroxene, glass, sulphide, silicates, Fluid inclusions
DS1992-1408
1992
Andersm M.H.Simpson, D.W., Andersm M.H.Tectonics and topography of the Western United States - an application Of digital mappingGsa Today, Vol. 2, No. 6, June pp. 117, 118, 120-121United StatesTectonics, Topography, GIS
DS1989-0243
1989
AndersonChandler, V.W., McSwiggen, P.L., Morey, G.B., Hinze, W.J., AndersonInterpretation of seismic reflection, gravity and magnetic dat a acrossAmerican Association Petrol. Geologists, Vol. 73, No. 3, March pp. 261-275Wisconsin, Minnesota, Iowa, MidcontinentTectonics, Geophysics
DS1993-0380
1993
AndersonDumont, R., Kiss, F., Stone, Anderson, Dostaler, JobinAeromagnetic surveys 1992-3. joint ventures -international coloboration MDAGeological Survey of Canada (GSC) Forum 1993, p. E12, F13-14. abstractManitobaGeophysics - magnetics
DS1998-1372
1998
AndersonSobolev, N.V., Yefimova, Channer, Anderson, BarronUnusual upper mantle beneath Guaniamo, Guyana Shield, Venezuela: evidence from diamond inclusions.Geology, Vol. 26, No. 11, Nov. pp. 971-974.VenezuelaEcogitic, peridotitic, ultrmafic type, Roraima Group
DS1998-1373
1998
AndersonSobolev, N.V., Yefimova, E.S., Channer, D., AndersonA unique eclogitic source of Guaniamo diamonds, Guyana Shield, Venezuela7th International Kimberlite Conference Abstract, pp. 829-31.Venezuela, GuyanaEclogites, Diamond genesis
DS1994-0047
1994
Anderson, A.Anderson, A., Dodds, A.R., McMahon, S., Street, G.J.A comparison of airborne, ground electromagnetic techniques for mapping shallow zone resistivity variationsAseg Volume, Vol. 24, No. 3, 4, pp. 323-332AustraliaGeophysics -airborne electromagnetic, Models
DS1994-1708
1994
Anderson, A.Street, G.J., Anderson, A.Airborne electromagnetic surveys of the regolithAseg Volume, Vol. 24, No. 3, 4, ppAustraliaGeophysics -electromagnetic, Alluvials
DS1860-0530
1887
Anderson, A.A.Anderson, A.A.Twenty Five Years in a Waggon in the Gold Regions of AfricaLondon: Chapman And Hall, TWO VOLUMESAfrica, South AfricaTravelogue
DS1995-0037
1995
Anderson, A.T.Anderson, A.T.CO2 and the eruptibility of picrite and komatiiteLithos, Vol. 34, No. 1-3, Jan. pp. 19-26GlobalKomatiite, Magmatism
DS1995-0038
1995
Anderson, A.T.Anderson, A.T.CO2 and the erupticibility of picrite and komatiiteLithos, Vol. 34, pp. 19-25.HawaiiPicrites, Magma crystallography
DS1997-0028
1997
Anderson, B.Anderson, B., Payne, J.Absorption spectra of diamondGemstone Press, Spectroscope and Gemology, pp. 214-22.GlobalDiamond spectroscopy, History, colour
DS1995-1809
1995
Anderson, B.D.Speilberg, N., Anderson, B.D.Seven ideas that shook the universeJohn Wiley, 355p. approx. $ 32.00 United StatesGlobalBook -ad, Astronomy, energy, conservation, symmetry
DS1975-0005
1975
Anderson, B.W.Anderson, B.W.Gem TestingLondon: 8th. Edition., 384P.GlobalKimberlite, Kimberley, Janlib, Gemology
DS2000-0230
2000
Anderson, C.Devaux, J.P., Fleitout, L., Anderson, C.Stresses in a subducting slab in the presence of a metastable olivine wedgeJournal of Geophysical Research, Vol. 105, No. 6, June 10, pp. 13365-74.MantleSubduction, Slab
DS2002-0036
2002
Anderson, C.Anderson, C.What would sustainability in the mining industry look like and how do we get there?Australian Institute of Mining and Metallurgy, No. 3/2002, pp.175-8.AustraliaMineral evaluation - sustainable development, Newmont
DS1910-0481
1916
Anderson, C.W.Anderson, C.W.New South Wales (1916)Sydney: William Applegate Gullick, New South Wales Surv. Dep, 164P.Australia, New South WalesDiamonds
DS1970-0183
1970
Anderson, C.W.Reitzel, J.S., Gough, D.I., Porath, H., Anderson, C.W.Geomagnetic Deep Sounding and Upper Mantle Structure in The western United States.Geophys. Journal of Res. Astron. Soc., Vol. 19, No. 3, PP. 213-235.GlobalGeophysics, Mid-continent
DS1996-0025
1996
Anderson, D.A.Anderson, D.A., Gibbs, B.L.Mining the internet.Mining Engineering, Vol. 48, No. 2, Feb. pp. 48-52United StatesMining, Computers -internet
DS1975-0006
1975
Anderson, D.L.Anderson, D.L.Chemical Plumes in the MantleGeological Society of America (GSA) Bulletin., Vol. 86, PP. 1593-1600.GlobalKimberlite Genesis
DS1975-0908
1979
Anderson, D.L.Anderson, D.L.The Upper Mantle Transition Region: Eclogite?Geophysical Research. LETTERS, Vol. 6, PP. 433-436.GlobalKimberlite Genesis
DS1982-0013
1982
Anderson, D.L.Anderson, D.L.Earth and Moon: Kimberlite and Kreep; a Study in Comparative Planetology.Geological Society of America (GSA), Vol. 14, No. 7, P. 432. (abstract.).GlobalGenesis
DS1982-0014
1982
Anderson, D.L.Anderson, D.L.Earth and Moon: Kimberlite and Kreep- a Study in Comparative Planetology.Geological Society of America (GSA), Vol. 14, No. 7, P. 432, (abstract.).GlobalKimberlite
DS1984-0013
1984
Anderson, D.L.Anderson, D.L.The New Global PetrologyEos, Vol. 66, No. 18, P. 233. (abstract.).GlobalComposition, Kimberlite, Ultramafic
DS1984-0014
1984
Anderson, D.L.Anderson, D.L.Kimberlite and the Evolution of the MantleProceedings of Third International Kimberlite Conference, Vol. 1, PP. 395-403.GlobalModel, Genesis, Isotope, Mid Ocean Ridge Basalt (morb), Kreep Relation, Geochronology
DS1984-0015
1984
Anderson, D.L.Anderson, D.L., Dziewonski, A.M.Seismic TomographySci. American, Vol. 251, No. 4, Oct. pp. 60-80.MantleTomography, Geophysics - Seismics
DS1986-0022
1986
Anderson, D.L.Anderson, D.L., Bass, J.D.Transition region of the earth's upper mantleNature, Vol. 320, No. 6060, March 27th. pp. 321-328GlobalMantle, Crustal genesis
DS1987-0010
1987
Anderson, D.L.Anderson, D.L.A seismic equation of State II. shear properties and thermodynamics of the lower mantlePhysics of the Earth and Planetary Interiors, Vol. 45, pp. 307-323GlobalMantle, Genesis
DS1989-0024
1989
Anderson, D.L.Anderson, D.L.Where on earth is the crust?Physics Today, Vol. 42, No. 3, March pp. 38-46GlobalMantle genesis
DS1989-0025
1989
Anderson, D.L.Anderson, D.L.Composition of the earthScience, Vol. 243, January 20, pp. 367-370. Database # 17580GlobalMantle, Genesis-geochemistry
DS1990-0117
1990
Anderson, D.L.Anderson, D.L.The importance of being eclogiteEos, Vol. 71, No. 17, April 24, p. 523 Abstract onlyGlobalExperimental petrology, Eclogite
DS1992-0024
1992
Anderson, D.L.Anderson, D.L.Mantle dynamics: the Hotcell modelEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 272MantleModel, Tectonics
DS1992-0025
1992
Anderson, D.L.Anderson, D.L., Tanimoto, T., Zhang, Yu-ShenPlate tectonics and hotspots: the third dimensionScience, Vol. 256, June 19, pp. 1645-1651MantleHot spots, Shear velocity
DS1992-0026
1992
Anderson, D.L.Anderson, D.L., Yu-Sheng Zhang, Tanimoto, T.Plume heads, continental lithosphere, flood basalts and tomographyGeological Society Special Publication Magmatism and the causes of the, No. 68, pp. 99-124GlobalMantle, Hotspots
DS1992-0027
1992
Anderson, D.L.Anderson, D.L., Zhang, Y., Tanimoto, T.Plume heads, continental lithosphere, flood basalts and tomographyStorey ed. Geological Society of London Special Paper, No. 68, pp. 99-124.MantleHot spots, plumes, volcanism.
DS1993-0031
1993
Anderson, D.L.Anderson, D.L.Helium -3 from the mantle: primordial signal or cosmic dust?Science, Vol. 261, July 9, pp. 170-176MantleHotspot magmas, helium
DS1994-0048
1994
Anderson, D.L.Anderson, D.L.Komatiites and picrites: evidence that the plume source is depletedEarth Planetary Science Letters, Vol. 128, No. 3-4, Dec. pp. 303-312MantleKomatiites, Plume, hot spots
DS1994-0049
1994
Anderson, D.L.Anderson, D.L.Komatiites and picrites: evidence that the plume source is depletedEarth and Planetary Science Letters, Vol. 128, pp. 303-311.MantlePicrites
DS1994-0050
1994
Anderson, D.L.Anderson, D.L.Lithosphere and flood basaltsNature, Vol. 367, No. 6460, January 20, p. 226-227.MantleSubduction
DS1994-0051
1994
Anderson, D.L.Anderson, D.L.Superplumes or supercontinents?Geology, Vol. 22, No. 1, January pp. 39-42MantleSupercontinents, Plate tectonics, Hot spots
DS1994-1442
1994
Anderson, D.L.Ray, T.W., Anderson, D.L.Spherical disharmonics in the earth sciences and the spatial solution:ridges, hotspots, slabs, geochemistryJournal of Geophysical Research, Vol. 99, No. B5, May 10, pp. 9605-9614.MantleGeochemistry, Tomography
DS1995-0039
1995
Anderson, D.L.Anderson, D.L.Lithosphere, asthenosphere and perisphereReviews of Geophysics, Vol. 33, No. 1, Feb. pp. 125-MantlePlate tectonics, Concepts -lithosphere, asthenosphere, perisphere
DS1995-1508
1995
Anderson, D.L.Polet, J., Anderson, D.L.Depth extent of cratons as inferred from tomographic studiesGeology, Vol. 23, No. 3, March pp. 205-208.Canada, South AfricaCraton, Tomography
DS1995-2046
1995
Anderson, D.L.Wen, L., Anderson, D.L.The fate of slabs inferred from seismic tomography and 130 million years ofsubduction.Earth and Planetary Science Letters, Vol. 133, pp. 185-198.MantleGeophysics -seismics, Subduction-slab
DS1996-0026
1996
Anderson, D.L.Anderson, D.L.Enriched asthenosphere and depleted plumesInternational Geology Review, Vol. 38, No. 1, pp. 1-21.MantlePetrology, Plumes
DS1996-0597
1996
Anderson, D.L.Hardebeck, J., Anderson, D.L.Eustasy as a test of a Cretaceous superplume hypothesisEarth and Planetary Science Letters, Vol. 137, No. 1/4, Jan. 1, pp. 101-108.MantleGeodynamics, Subduction, plumes
DS1996-1524
1996
Anderson, D.L.Wen, L., Anderson, D.L.Slabs, hotspots, cratons and mantle convection revealed from residual seismic tomography in the upper mantlePhysics of the Earth and Planetary Science Interiors, Vol. 99, pp. 131-143MantleHotspots, Craton
DS1997-1238
1997
Anderson, D.L.Wen, L., Anderson, D.L.Layered mantle convection: a model for geoid and topographyEarth and Planetary Letters, Vol. 146, No. 3/4. Feb 1, pp.367-378.MantleTomography
DS1998-0028
1998
Anderson, D.L.Anderson, D.L.The scales of mantle convectionTectonophysics, Vol. 284, No. 1-2, Jan. 15, pp. 1-18.MantleConvection - plumes, Tectonics
DS2000-0020
2000
Anderson, D.L.Anderson, D.L.The statistics and distribution of helium in the mantleInternational Geology Review, Vol. 42, No. 4, Apr 1, pp. 289-311.Mantlehelium, Mineral chemistry
DS2000-0021
2000
Anderson, D.L.Anderson, D.L.The thermal state of the Upper Mantle: no role for mantle plumesGeophysical Research Letters, Vol. 27, No. 22, Nov. 15, pp. 3623-26.MantlePlumes, Geothermometry
DS2000-0479
2000
Anderson, D.L.Keller, W.R., Anderson, D.L., Clayton, R.W.Resolution of tomographic models of the mantle beneath IcelandGeophysical Research Letters, Vol. 27, No. 24, Dec. 15, pp. 3993-6.GlobalTomography, Geophysics - seismic
DS2001-0024
2001
Anderson, D.L.Anderson, D.L.A statistical test of the two reservoir model for helium isotopesEarth and Planetary Science Letters, Vol. 193, No. 1-2, pp. 77-82.MantleGeochronology, geochemistry, statistics, OIB, MORB
DS2001-0025
2001
Anderson, D.L.Anderson, D.L.Top down tectonics?Science, No. 5537, Sept. 14, pp. 2016-17.MantleTectonics
DS2001-0026
2001
Anderson, D.L.Anderson, D.L.Plate tectonics as a far from equilibrium self organized systemAnderson, D.L., MantleBlank
DS2002-0037
2002
Anderson, D.L.Anderson, D.L.How many plates?Geology, Vol.30,5,May,pp. 411-4., Vol.30,5,May,pp. 411-4.GlobalTectonics, geodynamics, plates, list, area, Pattern, statistics
DS2002-0038
2002
Anderson, D.L.Anderson, D.L.How many plates?Geology, Vol.30,5,May,pp. 411-4., Vol.30,5,May,pp. 411-4.GlobalTectonics, geodynamics, plates, list, area, Pattern, statistics
DS2002-0039
2002
Anderson, D.L.Anderson, D.L.Mantle convection in the Earth and PlanetsMaterials Research Bulletin, Ingenta 1023992546, Vol. 37, 10, pp. 1781-84.MantleConvection
DS2002-0040
2002
Anderson, D.L.Anderson, D.L.The case for irreversible chemical stratification of the mantleInternational Geology Review, Vol. 44,2,Feb. pp. 97-116.MantleGeochemistry
DS2003-0017
2003
Anderson, D.L.Anderson, D.L.Plate tectonics: the general theory... the complex Earth is simpler than you thinkAnderson, D.L., MantleBlank
DS2003-0018
2003
Anderson, D.L.Anderson, D.L.Simple scaling relations in geodynamics: the role of pressure in mantle convectionAnderson, D.L., MantleBlank
DS2003-0417
2003
Anderson, D.L.Foulger, G.R., Anderson, D.L.Iceland is cool: an origin for the Iceland volcanic province in the remelting of subductedJournal of Geothermal Research, IcelandBlank
DS2003-0420
2003
Anderson, D.L.Foulger, G.R., Natland, J.H., Anderson, D.L.Iceland is fertile: the geochemistry of Icelandic lavas indicates extensive melting ofJournal of Geothermal Research, IcelandBlank
DS2003-0930
2003
Anderson, D.L.Meibom, A., Anderson, D.L.The statistical upper mantle assemblageEarth and Planetary Science Letters, MantleBlank
DS2003-0931
2003
Anderson, D.L.Meibom, A., Anderson, D.L., Sleep, N.H., Frei, R., Chamberlain, C.P., HrenAre high 3 He/ 4 He ratios in oceanic basalts an indicator of deep mantle plumeEarth and Planetary Science Letters, Vol. 208, 3-4, pp. 197-204.MantleHelium, Melting
DS2003-0932
2003
Anderson, D.L.Meibom, A., Anderson, D.L., Sleep, N.H., Frei, R., hamberlain, C.P., Hren, M.T.Are high 3He 4He ratios in oceanic basalts an indicator of deep mantle plumeEarth and Planetary Science Letters, Vol. 208, 3-4, March 30, pp.197-204.MantleGeochronology
DS200412-0035
2004
Anderson, D.L.Anderson, D.L.A short history of the plume hypothesis: the inside story.Anderson, D.L., 22p.MantlePlume history - discussion
DS200412-0036
2001
Anderson, D.L.Anderson, D.L.Plate tectonics as a far from equilibrium self organized system.Anderson, D.L., May 8, 18p.MantleDynamics, tectonics
DS200412-0037
2003
Anderson, D.L.Anderson, D.L.Plate tectonics: the general theory... the complex Earth is simpler than you think.Anderson, D.L., April 1, 22p.MantleDynamics, tectonics
DS200412-0038
2003
Anderson, D.L.Anderson, D.L.Simple scaling relations in geodynamics: the role of pressure in mantle convection.Anderson, D.L., Sept. 23p.MantleTectonics
DS200412-0569
2003
Anderson, D.L.Foulger, G.R., Anderson, D.L.Iceland is cool: an origin for the Iceland volcanic province in the remelting of subducted Iapetus slabs at normal mantle temperJournal of Geothermal Research, Vol. June 30p.Europe, IcelandGeophysics - seismics, mantle, plume
DS200412-0572
2003
Anderson, D.L.Foulger, G.R., Natland, J.H., Anderson, D.L.Iceland is fertile: the geochemistry of Icelandic lavas indicates extensive melting of subducted Iapetus crust in the CaledonianJournal of Geothermal Research, Vol. June 27p.Europe, IcelandEclogite, volcanism, subduction
DS200412-1289
2003
Anderson, D.L.Meibom, A., Anderson, D.L.The statistical upper mantle assemblage.Earth and Planetary Science Letters, Vol. 217, pp. 213-219.MantleGeochemistry
DS200412-1290
2004
Anderson, D.L.Meibom, A., Anderson, D.L.The statistical upper mantle assemblage.Earth and Planetary Science Letters, Vol. 217, 1, Jan. 1, pp. 123-139.MantleGeochemistry, Stratigraphy, MORB, SUMA
DS200412-1291
2004
Anderson, D.L.Meibom, A., Anderson, D.L.The statistical upper mantle assemblage.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A551MantleGeochemistry
DS200412-1292
2003
Anderson, D.L.Meibom, A., Anderson, D.L., Sleep, N.H., Frei, R., hamberlain, C.P., Hren, M.T., Wooden, J.L.Are high 3He 4He ratios in oceanic basalts an indicator of deep mantle plume components?Earth and Planetary Science Letters, Vol. 208, 3-4, March 30, pp.197-204.MantleGeochronology
DS200512-0016
2005
Anderson, D.L.Anderson, D.L.The layered mantle revisited... an eclogite reservoir.mantleplumes.org, 13p.MantleEclogite
DS200512-0017
2004
Anderson, D.L.Anderson, D.L.Simple scaling relations in geodynamics: the role of pressure in mantle convection and plume formation.Chinese Science Bulletin, Vol. 49, 19, pp. 2017-2020.China, mantleGeodynamics
DS200512-0018
2005
Anderson, D.L.Anderson, D.L.Scoring hotspots: the plume and plate paradigms.Plates, Plumes, and Paradigms, pp. 31-54. ( total book 861p. $ 144.00)GlobalPlume, hotspots - overview
DS200512-0019
2005
Anderson, D.L.Anderson, D.L., Natland, J.H.A brief history of the plume hypothesis and its competitors: concept and controversy.Plates, Plumes, and Paradigms, pp. 119-146. ( total book 861p. $ 144.00)GlobalOrigin - history
DS200512-0020
2005
Anderson, D.L.Anderson, D.L., Schramm, K.A.Global hotspot maps.Plates, Plumes, and Paradigms, pp. 19-30. ( total book 861p. $ 144.00)GlobalPlume, hotspots - overview
DS200512-0298
2005
Anderson, D.L.Foulger, G.R., Anderson, D.L.A cool model for the Iceland hotspot.Journal of Volcanology and Geothermal Research, Vol. 141, 1-2, March 1, pp. 1-22.Europe, IcelandMagmatism, subduction, tectonics
DS200512-0299
2005
Anderson, D.L.Foulger, G.R., Natland, J.H., Anderson, D.L.A source for Icelandic magmas in remelted Iapetus crust.Journal of Volcanology and Geothermal Research, Vol. 141, 1-2, March 1, pp.23-44.Europe, IcelandRecycled, subduction, tectonics, plates, gechemistry
DS200512-0300
2005
Anderson, D.L.Foulger, G.R., Natland, J.H., Anderson, D.L.Genesis of Iceland melt anomaly by plate tectonic processes.Plates, Plumes, and Paradigms, pp. 595-626. ( total book 861p. $ 144.00)Europe, IcelandTectonics - melting
DS200512-0704
2005
Anderson, D.L.McHone, J.G., Anderson, D.L., Beutel, E.K., Fialko, Y.A.Giant dikes, rifts, flood basalts, and plate tectonics: a contention of mantle models.Plates, Plumes, and Paradigms, pp. 401-420. ( total book 861p. $ 144.00)MantleDikes, rifting
DS200512-0715
2005
Anderson, D.L.Meibom, A., Sleep, N.H., Zahnle, K., Anderson, D.L.Models for noble gases in mantle geochemistry: some observations and alternatives.Plates, Plumes, and Paradigms, pp. 347-364. ( total book 861p. $ 144.00)MantleGeochemistry
DS200512-0931
2005
Anderson, D.L.Sandwell, D., Anderson, D.L., Wessel, P.Global tectonic maps.Plates, Plumes, and Paradigms, pp. 1-10 ( total book 861p. $ 144.00)GlobalTectonics - overview
DS200612-0018
2006
Anderson, D.L.Anderson, D.L.The layered mantle revisited: an eclogite reservoir.mantleplumes.org, 8p. downloadMantleEclogite
DS200612-0019
2005
Anderson, D.L.Anderson, D.L.Self-gravity, self-consistency, and self-organization in geodynamics and geochemistry.American Geophysical Union, Geophysical Monograph, ed. Van der Hilst, Earth's Deep mantle, structure ...., No. 160, pp. 165-186.MantleGeodynamics
DS200612-0020
2006
Anderson, D.L.Anderson, D.L.Speculations on the nature and cause of mantle heterogeneity.Tectonophysics, Vol. 416, 1-4, April 5, pp. 7-22.MantleGeophysics - seismics
DS200612-0021
2006
Anderson, D.L.Anderson, D.L.The plate paradigm.mantleplumes.org, 4p.MantlePlume
DS200612-0022
2005
Anderson, D.L.Anderson, D.L.Large igneous provinces, delamination and fertile mantle.Elements, Vol. 1, 5, December pp. 271-276.MantleTectonics
DS200612-1426
2006
Anderson, D.L.Thybo, H., Anderson, D.L.The heterogeneous mantle.Tectonophysics, Vol. 416, 1-4, April 5, pp. 1-6.MantleSpecial issue
DS200712-0015
2006
Anderson, D.L.Anderson, D.L.Definition of a plume.mantleplumes.org, 5p.MantleHypothesis
DS200712-0016
2006
Anderson, D.L.Anderson, D.L.Plate tectonics, the general theory: complex Earth is simpler than you think.Geological Society of America Special Paper, No. 413, pp. 29-38.MantleTectonics
DS200712-0017
2007
Anderson, D.L.Anderson, D.L.The eclogite engine: chemical geodynamics as a Galileo thermometer.Plates, plumes and Planetary Processes, pp. 47-64.MantleGeothermometry - eclogites
DS200812-0030
2007
Anderson, D.L.Anderson, D.L.Evidence for mantle plumes?Nature, Vol. 450, 7169, p. E15.MantlePlume
DS200812-0031
2008
Anderson, D.L.Anderson, D.L.The eclogite engine: top down geochemistry.Goldschmidt Conference 2008, Abstract p.A24.MantleEclogite
DS200812-0032
2008
Anderson, D.L.Anderson, D.L.The eclogite engine: cool LIPsGoldschmidt Conference 2008, Abstract p.A25.MantleEclogite
DS200812-0033
2008
Anderson, D.L.Anderson, D.L.Crustal and mantle cycles.Goldschmidt Conference 2008, Abstract p.A24.MantleEclogite
DS201112-0019
2011
Anderson, D.L.Anderson,D.L.Hawaii, boundary layers and ambient mantle - geophysical constraints.Journal of Petrology, Vol. 52, 7-8, pp. 1547-1577.MantleGeophysics
DS201312-0020
2013
Anderson, D.L.Anderson, D.L.The persistent mantle plume myth.Australia Journal of Earth Sciences, Vol. 60, 6-7, pp. 657-673.MantleHotspots
DS201312-0021
2013
Anderson, D.L.Anderson, D.L.Mantle jets and mantle plumes.Goldschmidt 2013, AbstractMantleHotspots
DS201501-0002
2014
Anderson, D.L.Anderson, D.L., King, S.D.Driving the Earth machine?Science, Vol. 346, 6214, pp. 1184-1185.MantleAthenosphere, magmatism

Abstract: The asthenosphere—derived from the Greek asthen?s, meaning weak—is the uppermost part of Earth's mantle, right below the tectonic plates that make up the solid lithosphere. First proposed by Barrell 100 years ago (1), the asthenosphere has traditionally been viewed as a passive region that decouples the moving tectonic plates from the mantle and provides magmas to the global spreading ridge system. Recent studies suggest that the asthenosphere may play a more active role as the source of the heat and magma responsible for intraplate volcanoes. Furthermore, it may have a major impact on plate tectonics and the pattern of mantle flow.
DS201508-0362
2015
Anderson, D.L.Lee, C-T.A., Anderson, D.L.Continental crust formation at arcs, the arclogite "delamination" cycle, and one origin for fertile melting anomalies in the mantle.Science Bulletin, DOI: 10.1007/s11434-015-088-6 online 16p.MantleEclogite
DS201511-1832
2015
Anderson, D.L.Doglioni, C., Anderson, D.L.Top-driven asymmetric mantle convection.Geological Society of America Special Paper, No. 514, pp. SPE514-05.MantleConvection

Abstract: The role of decoupling in the low-velocity zone is crucial for understanding plate tectonics and mantle convection. Mantle convection models fail to integrate plate kinematics and thermodynamics of the mantle. In a first gross estimate, we computed at >300 km3/yr the volume of the plates lost along subduction zones. Mass balance predicts that slabs are compensated by broad passive upwellings beneath oceans and continents, passively emerging at oceanic ridges and backarc basins. These may correspond to the broad low-wavespeed regions found in the upper mantle by tomography. However, west-directed slabs enter the mantle more than three times faster (?232 km3/yr) than in the opposite east- or northeast-directed subduction zones (?74 km3/yr). This difference is consistent with the westward drift of the outer shell relative to the underlying mantle, which accounts for the steep dip of west-directed slabs, the asymmetry between flanks of oceanic ridges, and the directions of ridge migration. The larger recycling volumes along west-directed subduction zones imply asymmetric cooling of the underlying mantle and that there is an "easterly" directed component of the upwelling replacement mantle. In this model, mantle convection is tuned by polarized decoupling of the advecting and shearing upper boundary layer. Return mantle flow can result from passive volume balance rather than only by thermal buoyancy-driven upwelling.
DS201511-1862
2015
Anderson, D.L.Lustrino, M., Anderson, D.L.The mantle isotopic printer: basic mantle plume geochemistry for seismologists and geodynamicists.Geological Society of America Special Paper, No. 514, pp. SPE514-16.MantlePhysics

Abstract: High-temperature geochemistry combined with igneous petrology is an essential tool to infer the conditions of magma generation and evolution in the Earth’s interior. During the last thirty years a large number of geochemical models of the Earth, essentially inferred from the isotopic composition of basaltic rocks, have been proposed. These geochemical models have paid little attention to basic physics concepts, broad-band seismology, or geological evidence, with the effect of producing results that are constrained more by assumptions than by data or first principles. This may not be evident to seismologists and geodynamicists. A common view in igneous petrology, seismology and mantle modelling is that isotope geochemistry (e.g., the Rb-Sr, Sm-Nd, U-Th-Pb, U-Th-He, Re-Os, Lu-Hf, and other more complex systems) has the power to identify physical regions in the mantle, their depths, their rheological behaviour and the thermal conditions of magma generation. We demonstrate the fallacy of this approach and the model-dependent conclusions that emerge from unconstrained or poorly constrained geochemical models that do not consider physics, seismology (other than teleseismic travel time tomography and particularly compelling colored mantle cross sections) and geology. Our view may be compared with computer printers. These can reproduce the entire range of colors using a limited number of basic colors (black, magenta, yellow, and cyan). Similarly, the isotopic composition of oceanic basalts and nearly all their primitive continental counterparts can be expressed in terms of a few mantle end-members. The four most important (actually "most extreme", since some are extraordinarily rare) mantle end-members identified by isotope geochemists are DMM or DUM [Depleted MORB (mid-ocean-ridge basalt) Mantle or Depleted Upper Mantle], HiMu (High-Mu, where Mu = ? = 238U/204Pb), EMI and EMII (Enriched Mantle type I and type II). Other mantle end-members, or components, have been proposed in the geochemical literature (e.g., PHeM, FoZo, LVC, PreMa, EMIII, CMR, LoMu, and C) but these can be considered to be less extreme components or mixtures in the geochemical mantle zoo. Assuming the existence of these extreme "colors" in the mantle isotopic printer, the only matter for debate is their location in the Earth’s interior. At least three need long-time insulation from convection-driven homogenization or mixing processes. In other words, it needs to be defined where these extreme isotopic end-members are located. In our view, no geochemical, geological, geophysical and physical arguments require the derivation of any basalt or magma from the deep mantle. Arguments to the contrary are assumption-based. The HiMu, EMI and EMII end-members can be entirely located in the shallow non-convecting volume of the mantle, while the fourth, which is by far the more abundant volumetrically, (DMM or DUM) can reside in the Transition Zone. This view is inverted compared with current canonical geochemical views of the Earth’s mantle, where the shallowest portions are assumed to be DMM-like (ambient mantle) and the EMI-EMII-HiMu end-members are assumed to be isolated, located in the deep mantle, and associated with thermal anomalies. We argue that the ancient, depleted signatures of DMM imply long-term isolation from recycling and crustal contamination while the enriched components are not free of contamination by shallow materials and can therefore be shallow.
DS1995-0040
1995
Anderson, D.M.Anderson, D.M.Managing environmental liability during mine closure and post closure utilization or property transferAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, No. 95-226, 4pNevadaMining, Legal -environmental closure
DS1996-0027
1996
Anderson, D.N.Anderson, D.N., Decker, D.T., Valladares, C.E.Modeling boundary blobs using time varying invectionGeophys. Research Letters, Vol. 23, No. 5, March 1, pp 579-582MantleGeophysics -seismics, Boundary
DS1997-0806
1997
Anderson, E.D.Moecher, D.P., Anderson, E.D., Cook, C.A., Mezger, K.The petrogenesis of metamorphosed carbonatites in the Grenville Province, Ontario.Canadian Journal of Earth Sciences, Vol. 34, No. 9, Sept. pp. 1185-1201.OntarioCarbonatite, Central Metasedimentary Belt zone
DS1997-0807
1997
Anderson, E.D.Moecher, D.P., Anderson, E.D., Cook, C.A., Mezger, K.Petrogenesis of Grenville carbonatitesGeological Association of Canada (GAC) Abstracts, OntarioCarbonatite, Petrology
DS1998-1026
1998
Anderson, E.D.Moecher, D.P., Haynes, E.A., Anderson, E.D., Cook, C.A.Petrogenesis of metamorphosed Grenville carbonatites, OntarioGeological Society of America (GSA) Annual Meeting, abstract. only, p.A26.OntarioPetrology, Carbonatite - genesis
DS200512-0997
2004
Anderson, E.D.Sims, P.K., Peterman, Z.E., Anderson, E.D.Early tectonic evolution of the North America continent - a model invoking subcontinental mantle deformation.Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 244-2, Vol. 36, 5, p. 567.United States, CanadaTectonics
DS200712-0018
2007
Anderson, E.D.Anderson, E.D., Moecher, D.P.Omphacite breakdown reactions and relation to eclogite exhumation rates.Contributions to Mineralogy and Petrology, Vol. 154, 3m pp. 253-277.MantleEclogite
DS1981-0006
1981
Anderson, F.J.Anderson, F.J.Riches of the Earth; Ornamental, Precious and Semi-preciousstones.New York: Rutledge Press, 224P.GlobalDiamond
DS2003-0587
2003
Anderson, I.M.Hiraga, T., Anderson, I.M., Kohlstedt, D.L.Chemistry of grain boundaries in mantle rocksAmerican Mineralogist, Vol. 88, 7 July, pp. 1015-19.MantleSTEM, EDX, chemical segregation, Geochemistry
DS2003-0588
2003
Anderson, I.M.Hiraga, T., Anderson, I.M., Kohlstedt, D.L.Chemistry of grain boundaries in mantle rocksAmerican Mineralogist, Vol. 88, pp. 1015-19.MantleBlank
DS200412-0833
2003
Anderson, I.M.Hiraga, T., Anderson, I.M., Kohlstedt, D.L.Chemistry of grain boundaries in mantle rocks.American Mineralogist, Vol. 88, 7 July, pp. 1015-19.MantleSTEM, EDX, chemical segregation Geochemistry
DS1859-0029
1820
Anderson, J.Anderson, J.Account of the Strat a of the Diamond Mines at MallivullyEdinburgh Phil. Journal, Vol. 3, PP. 72-73.India, Andhra PradeshStratigraphy
DS1920-0311
1927
Anderson, J.E.Anderson, J.E.Impressions of the Lichtenburg Diamond FieldsMining Engineering Journal of South Africa, Vol. 38, PT. 1, No. 1858, PP. 259-260.South Africa, TransvaalTravelogue
DS1997-0029
1997
Anderson, J.E.Anderson, J.E., Gordine, A.Environmental regulations affecting the mining industry in RussiaMining in Russia Conference Northern Miner, Oct, Toronto, 12pRussiaEnvironment, Legal
DS1985-0065
1985
Anderson, J.L.Bickford, M.E., Anderson, J.L.Proterozoic Granite-rhyolite Terranes of the Southern Midcontinent, Usa6th. International Conference Basement Tectonics, Held Sante Fe, Septem, P. 11. (abstract.).United States, Colorado Plateau, Colorado, Wet Mountains, Central StatesGeotectonics
DS2003-0515
2003
Anderson, J.M.Gu, Y., Anderson, J.M.Geometric processing of hyper spectral image dat a acquired by VIFIS on board lightInternational Journal of Remote Sensing, Vol. 24, 23, Dec. pp. 4681-4698GlobalVariable-Interference-Filter Imaging Spectrometer (VIFIS), airborne imaging
DS200412-0737
2003
Anderson, J.M.Gu, Y., Anderson, J.M.Geometric processing of hyper spectral image dat a acquired nu VIFIS on board light aircraft.International Journal of Remote Sensing, Vol.24, no. 23, Dec.pp. 4681-99.TechnologyRemote sensing - hyperspectral
DS1995-0041
1995
Anderson, K.Anderson, K.Mining, privatization and the environmentRaw Materials Report, Vol. 11, No. 3, pp. 25-28CanadaLegal, Environment
DS1995-0042
1995
Anderson, K.Anderson, K.Toward the management of mining environmental conflictsSeg Newsletter, No. 21, April pp. 8, 9United StatesMining, Environment
DS1996-0028
1996
Anderson, K.Anderson, K.Proceedings of the International conference on resources, risk andresponsibilityCentre for Resource Studies, due in Spring $ 70.00GlobalBook -ad, Resources, risk and responsibility
DS1996-0029
1996
Anderson, K.Anderson, K.Mining development fundamentalsProspectors and Developers Association of Canada (PDAC) Short Course for Developing Country, pp. 1-8GlobalMining, Short course notes
DS201710-2210
2017
Anderson, K.R.Anderson, K.R., Poland, M.P.Abundant carbon in the mantle beneath Hawaii.Nature Geoscience, Vol. 10, 9, pp. 704-708.United States, Hawaiicarbon

Abstract: Estimates of carbon concentrations in Earth’s mantle vary over more than an order of magnitude, hindering our ability to understand mantle structure and mineralogy, partial melting, and the carbon cycle. CO2 concentrations in mantle-derived magmas supplying hotspot ocean island volcanoes yield our most direct constraints on mantle carbon, but are extensively modified by degassing during ascent. Here we show that undegassed magmatic and mantle carbon concentrations may be estimated in a Bayesian framework using diverse geologic information at an ocean island volcano. Our CO2 concentration estimates do not rely upon complex degassing models, geochemical tracer elements, assumed magma supply rates, or rare undegassed rock samples. Rather, we couple volcanic CO2 emission rates with probabilistic magma supply rates, which are obtained indirectly from magma storage and eruption rates. We estimate that the CO2 content of mantle-derived magma supplying Hawai‘i’s active volcanoes is 0.97?0.19+0.25 wt% -roughly 40% higher than previously believed-and is supplied from a mantle source region with a carbon concentration of 263?62+81?ppm. Our results suggest that mantle plumes and ocean island basalts are carbon-rich. Our data also shed light on helium isotope abundances, CO2/Nb ratios, and may imply higher CO2 emission rates from ocean island volcanoes.
DS1982-0015
1982
Anderson, M.Anderson, M.Diamond Appraisals Vary Store to StoreSunday Star (toronto), Oct. 10TH, P. A 17.GlobalKimberlite, Diamond, Appraisal
DS200912-0802
2008
Anderson, M.L.Wagner, L.B., Anderson, M.L., Jackson, J.M., Beck, S.L., Zandt,G.Seismic evidence for orthopyroxene enrichment in the continental lithosphere.Geology, Vol. 36, 12, Dec. pp. 936=938.MantleGeophysics - seismics
DS1992-0028
1992
Anderson, M.P.Anderson, M.P., Woessner, W.W.Applied groundwater modeling... simulation flow and advective transportAcademic Press, 381p. $ 70.00 United StatesGlobalBook -ad, Groundwater modeling
DS1970-0528
1972
Anderson, O.L.Helmstaedt, H., Anderson, O.L., Gavasci, A.T.Petrofabric Studies of Eclogite, Spinel-websterite, and SpinJournal of Geophysical Research, Vol. 77, PP. 4350-4365.United States, Utah, Arizona, Colorado PlateauBlank
DS1970-0619
1973
Anderson, O.L.Anderson, O.L., Perkins, P.A Plate Tectonics Model Involving Nonlaminar Asthenospheric flow to Account for Irregular Patterns of Magmatism in the Southwestern United States.International Kimberlite Conference FIRST, EXTENDED ABSTRACT VOLUME., PP. 7-10.Colorado PlateauKimberlite, Rocky Mountains
DS1975-0007
1975
Anderson, O.L.Anderson, O.L., Perkins, P.A Plate Tectonics Model Involving Non-laminar Asthenospheric Flow to Account for Irregular Patterns of Magmatism in The southwestern United States.Physics and Chemistry of the Earth, Vol. 9, PP. 113-122.United States, Colorado Plateau, Rocky MountainsKimberlite Genesis
DS1975-0909
1979
Anderson, O.L.Anderson, O.L.The Role of Fracture Dynamics in Kimberlite Pipe FormationInternational Kimberlite Conference SECOND., Vol. 1, PP. 344-353.GlobalKimberlite, Genesis
DS1995-0043
1995
Anderson, O.L.Anderson, O.L., Masuda, K., Guo, D.Pure silicate perovskite and the PREM lower mantle model: a thermodynamicanalysis.Physics of the Earth and Plan. Interiors, Vol. 89, pp. 35-49.MantlePerovskite
DS2002-0041
2002
Anderson, O.L.Anderson, O.L.The power balance at the core mantle boundaryEarth and Planetary Science Letters, Vol.131, 1, pp. 1-17.MantleUHP
DS1992-1348
1992
Anderson, P.F.Schulze, D.J., Anderson, P.F.Composition and significance of xenocrystal garnet, chromite, and ilmenite from diamond bearing kimberlites in the Kirkland Lake cluster.Ontario Geological Survey Mineral Development Forum - POSTER December 7th., AbstractOntarioGeochemistry, indicators, Kirkland Lake cluster
DS1992-1349
1992
Anderson, P.F.Schulze, D.J., Anderson, P.F.Composition and significance of xenocrystal garnet, chromite and ilmenite from diamond bearing kimberlites in the Kirkland Lake cluster.Ontario Geological Survey, Ontario Mines and Minerals Symposium held Dec., Poster abstract only, p. 54.OntarioMineral chemistry, Indicator minerals
DS1994-1556
1994
Anderson, P.F.N.Schulze, D.J., Anderson, P.F.N.Indicator mineral chemistry of Kirkland Lake kimberlitesGeological Association of Canada (GAC) Abstract Volume, Vol. 19, p.OntarioGeochemistry, Kirkland Lake area
DS1995-1679
1995
Anderson, P.F.N.Schulze, D.J., Anderson, P.F.N., Hetman, C.M.Origin and significance of ilmenite megacrysts and macrocrysts fromkimberlite.International Geology Review, Vol. 37, No. 9, Sept. pp. 780-812.GlobalKimberlite, Petrology -ilmenite
DS1995-0044
1995
Anderson, R.B.Anderson, R.B., Bone, R.M.First Nations economic development: a contingency perspectiveCanadian Geographer, Vol. 39, No. 2, pp. 120-130CanadaLegal, Aborigines
DS1989-1651
1989
Anderson, R.G.Woodsworth, G.J., Anderson, R.G., Armstrong, et al.A database of plutonic regimes in the Canadian CordilleraGeological Survey of Canada (GSC) Open file, No. 2369, 1:1, 000, 000Alberta, CordilleraDiatremes
DS1990-1298
1990
Anderson, R.G.Samson, S.D., Patchett, P.J., Gehrels, G.E., Anderson, R.G.neodymium and Strontium isotopic characterization of the Wrangellia Terrane and implications for crustal growth of the Canadian CordilleraJournal of Geology, Vol. 98, pp. 749-762British ColumbiaTerrane - Wrangellia, Geochronology
DS2001-0027
2001
Anderson, R.G.Anderson, R.G., Resnick, J., Russell, J.K., WoodsworthThe Cheslatta Lake suite: Miocene mafic, alkaline magmatism in central British Columbia.Canadian Journal of Earth Sciences, Vol. 38, No. 4, Apr. pp. 697-717.British Columbia, CordilleraAlkaline rocks, Magmatism - not specific to diamonds
DS1981-0007
1981
Anderson, R.L.Anderson, R.L.The Origin and Significance of Photolineaments in Southeastern Nebraska.Msc. Thesis, University Nebraska., GlobalMid-continent, Tectonics
DS1981-0008
1981
Anderson, R.R.Anderson, R.R., Black, R.A.Geophysical Interpretation of the Geology of the Central Segment of the Midcontinent.Eos, Vol. 63, No. 33, P. 615. (abstract.).GlobalMid-continent
DS1982-0613
1982
Anderson, R.R.Van eck, O.J., Anderson, R.R., Cumerlato, C.L., et al.Regional Tectonics and Seismicity of Southwestern IowaIowa State Geological Survey, NUREG CR 3021, 72P. (NOVEMBER).GlobalMid-continent, Gravity, Geophysics, Thurman-redfield
DS1983-0011
1983
Anderson, R.R.Anderson, R.R., Black, R.A.Early Proterozoic Development of the Southern Archean Boundary of the Superior Province in the Lake Superior Region.Geological Society of America (GSA), Vol. 15, No. 6, P. 515. (abstract.).GlobalMid Continent
DS1988-0011
1988
Anderson, R.R.Anderson, R.R.Phanerozoic structural features in the northern mid- continentMissouri Department of Natural Resources, and United States Geological Survey (USGS), miscellaneous Field study maps MF 1835-E, $ 2.40ArkansasMap, Tectonics
DS1989-1539
1989
Anderson, R.R.Van Schmus. W.R., Bickford, M.E., Anderson, R.R., Shearer, C.K.Quimby, Iowa scientific drill hole: definition of Precambrian crustal features in northwestern IowaGeology, Vol. 17, No. 6, June pp. 536-539IowaMidcontinent, Drilling
DS1993-1745
1993
Anderson, R.R.Windom, K.E., Van Schmus, W.R., Seifert, K.E., Wallin, E.T., Anderson, R.R.Archean and Proterozoic tectono-magmatic activity along the southern Margin of the Superior Province in northwestern Iowa, United States.Canadian Journal of Earth Sciences, Vol. 30, No. 6, June pp. 1275-1285.IowaTectonics
DS1996-0030
1996
Anderson, R.R.Anderson, R.R., McKay, R.M.Geologic controls on the configuration of the Precambrian surface in IowaGeological Society of America (GSA) abstract Vol., Vol. 28, No. 6, May p. 26.IowaPrecambrian basement
DS202008-1385
2020
Anderson, R.R.Drenth, B.J., Souders, A.K., Schulz, K.J., Feinberg, J.M., Anderson, R.R., Chandler, V.W., Cannon, W.L., Clark, R.J.Evidence for a concealed Midcontinent Rift related northeast Iowa intrusive complex.Precambrian Research, in press available, 43p. PdfUnited States, Iowageophysics - seismics

Abstract: Large amplitude aeromagnetic and gravity anomalies over a ~9500 km2 area of northeast Iowa and southeast Minnesota have been interpreted to reflect the northeast Iowa intrusive complex (NEIIC), a buried intrusive igneous complex composed of mafic/ultramafic rocks in the Yavapai Province (1.8-1.7 Ga). Hundreds of meters of Paleozoic sedimentary cover and a paucity of basement drilling have prevented detailed studies of the NEIIC. Long considered, but not proven, to be related to the ~1.1 Ga Midcontinent Rift System (MRS), the NEIIC is comparable in areal extent to the richly mineralized Duluth Complex and is similarly located near the margin of the MRS. New geochronological and geophysical data together support an MRS affinity for the NEIIC. A dike swarm imaged in aeromagnetic data is cut by intrusions of the NEIIC, and a new apatite U-Pb date of ~1170 Ma on one of the dikes thus represents a maximum age for the NEIIC. A minimum age constraint is suggested by (1) large-volume magmatism associated with the MRS that was the last such event to affect the region; and (2) the presence of reversely magnetized dikes, similar in character to MRS-related dikes elsewhere, that cut several intrusions of the NEIIC. The NEIIC is largely characterized by the presence of multiple zoned intrusions, many of which contain large volumes of mafic-ultramafic rocks and have strong geophysical similarities to alkaline intrusive complexes elsewhere, including the MRS-related Coldwell Complex of Ontario. The largest of the zoned intrusions are ~40 km in diameter and are interpreted to have thicknesses of many kilometers. Suspected faults, alignments of intrusions, and intrusive margins tend to be aligned along northwest and northeast trends that match the trends of the Belle Plaine fault zone and Fayette structural zone, both previously interpreted as pre-MRS, possibly lithospheric-scale discontinuities that may have controlled NEIIC emplacement. These interpretations collectively imply notable potential for the NEIIC to host several different types of undiscovered base metal and critical mineral deposits.
DS202010-1839
2020
Anderson, R.R.Drenth, N.J., Souders, A.K., Schulz, K.J., Feinberg, J.M., Anderson, R.R., Chandler, V.W., Cannon, W.F., Clark, R.J.Evidence for a concealed Midcontinent Rift related northeast Iowa intrusive complex.Precambrian Research, Vol. 347, 105845, 23p. PdfUnited States, Iowageochronology, geophysics - gravity

Abstract: Large amplitude aeromagnetic and gravity anomalies over a ~9500 km2 area of northeast Iowa and southeast Minnesota have been interpreted to reflect the northeast Iowa intrusive complex (NEIIC), a buried intrusive igneous complex composed of mafic/ultramafic rocks in the Yavapai Province (1.8-1.7 Ga). Hundreds of meters of Paleozoic sedimentary cover and a paucity of basement drilling have prevented detailed studies of the NEIIC. Long considered, but not proven, to be related to the ~1.1 Ga Midcontinent Rift System (MRS), the NEIIC is comparable in areal extent to the richly mineralized Duluth Complex and is similarly located near the margin of the MRS. New geochronological and geophysical data together support an MRS affinity for the NEIIC. A dike swarm imaged in aeromagnetic data is cut by intrusions of the NEIIC, and a new apatite U-Pb date of ~1170 Ma on one of the dikes thus represents a maximum age for the NEIIC. A minimum age constraint is suggested by (1) large-volume magmatism associated with the MRS that was the last such event to affect the region; and (2) the presence of reversely magnetized dikes, similar in character to MRS-related dikes elsewhere, that cut several intrusions of the NEIIC. The NEIIC is largely characterized by the presence of multiple zoned intrusions, many of which contain large volumes of mafic-ultramafic rocks and have strong geophysical similarities to alkaline intrusive complexes elsewhere, including the MRS-related Coldwell Complex of Ontario. The largest of the zoned intrusions are ~40 km in diameter and are interpreted to have thicknesses of many kilometers. Suspected faults, alignments of intrusions, and intrusive margins tend to be aligned along northwest and northeast trends that match the trends of the Belle Plaine fault zone and Fayette structural zone, both previously interpreted as pre-MRS, possibly lithospheric-scale discontinuities that may have controlled NEIIC emplacement. These interpretations collectively imply notable potential for the NEIIC to host several different types of undiscovered base metal and critical mineral deposits.
DS1991-0565
1991
Anderson, S.B.Gerhard, L.C., Anderson, S.B., Fischer, D.W.Petroleum geology of the Wiliston Basinin: Interior cratonic basins, ed. Leighton, M.W. et al., American Association of Petroleum Geologists Memoir No. 51, Chpater 29, pp. 507-559SaskatchewanBasin, Geology ( specific to petroleum but useful)
DS200912-0061
2008
Anderson, S.D.Bohm, C.O., Anderson, S.D., Matile, G.L.D., Keller, G.R.Geochemical and kimberlite indicator mineral results for till samples from Nejanilini, Kasmere and Putahow lakes areas, northern Manitoba NTS 64N 64 O 64 P.Manitoba Geological Survey, OF 2008-13, CDCanada, ManitobaGeochemistry
DS201711-2498
2017
Anderson, S.D.Anderson, S.D.Preliminary geology of the diamond occurrence at southern Knee Lake, Oxford Lake-Knee Lake greenstone belt, Manitoba ( NTS 53L15).Manitoba Geological Survey, Open File OF2017-3, 34p. PdfCanada, Manitobageochemistry
DS1991-1204
1991
Anderson, T.B.Murphy, F.C., Anderson, T.B., et al.An appraisal of Caledonian suspect terranes in IrelandIrish Journal of Earth Sciences, Vol. 11, December pp. 11-41IrelandTerrane, Structure, tectonics
DS1996-0031
1996
Anderson, T.B.Anderson, T.B., Oliver, G.J.H.Xenoliths of Iapetus suture mylonites in County Down lamprophyres NorthernIreland.Journal of Geology Society of London, Vol. 153, No. 3, May 1, pp. 403-408.IrelandLamprophyres
DS2003-0527
2003
Anderson, T.B.Hacker, B.R., Anderson, T.B., Root, D.B., Mehl, L., Mattinson, J.M., WoodenExhumation of high pressure rocks beneath the Solund Basin, Western gneiss regionJournal of Metamorphic Geology, Vol. 21, 6, pp. 613-30.NorwayUHP
DS200412-0758
2003
Anderson, T.B.Hacker, B.R., Anderson, T.B., Root, D.B., Mehl, L., Mattinson, J.M., Wooden, J.L.Exhumation of high pressure rocks beneath the Solund Basin, Western gneiss region, Norway.Journal of Metamorphic Geology, Vol. 21, 6, pp. 613-30.Europe, NorwayUHP
DS200612-0023
2006
Anderson, U.B.Anderson, U.B., Eklund, O., Frjd, S., Konopelko, D.1.8 Ga magmatism in the Fennoscandian Shield; lateral variations in subcontinental mantle enrichment.Lithos, Vol. 86, 1-2, pp. 110-136.Europe, Finland, Sweden, Kola PeninsulaMagmatism
DS1986-0674
1986
Anderson, V.G.Robinson, D.N., Scott, J.A., Van Niekerk, A., Anderson, V.G.Events reflected in the diamonds of some southern African kimberlitesProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 421-423South AfricaDiamond morphology
DS1989-1285
1989
Anderson, V.G.Robinson, D.N., Scott, J.A., Van Niekerk, A., Anderson, V.G.The sequence of events reflected in the diamonds of some southern AfricankimberlitesGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 990-1000South AfricaDiamond morphology, Diamond characteristics
DS1998-1244
1998
Anderson, V.G.Robinson, D.N., Ferraris, R., Anderson, V.G., ParkerColour, morphological and surface textural characteristics of diamonds in Venetia kimberlites.7th. Kimberlite Conference abstract, pp. 737-40.South AfricaDiamond morphology, Deposit - Venetia
DS1860-0576
1888
Anderson, W.Anderson, W.Report of Progress for 1887, Appendix No. 8 and Appendix No. 9 by the Geological Surveyor in Charge.New South Wales Geological Survey Report For 1887, PP. 155-159.Australia, New South WalesDiamond Occurrence
DS1900-0085
1902
Anderson, W.Anderson, W.Supposed Diamondiferous Deposits of LebomboGeological Survey NATAL AND ZULULAND (Cape Town), FIRST REPORT PP. 63-65.Africa, South AfricaHistory, Diamond, Prospecting
DS1989-1113
1989
Anderson, W.L.Newman, G.A., Anderson, W.L., Hohmann, G.W.Effect of conductive host rock on borehole transient electromagneticresponsesGeophysics, Vol. 54, No. 5, May pp. 598-608GlobalGeophysics, electromagnetic -host rock
DS1992-0029
1992
Anderson, W.L.Anderson, W.L.Inversion of plane-wave electromagnetic dat a for layered Earth models using a graphical user interfaceUnited States Geological Survey (USGS) Open File, No. 92-0518 A, B, $ 10.25GlobalComputer, Program - electromagnetic
DS1995-0101
1995
Anderson, W.L.Bankey, V., Anderson, W.L.A bibliography of some geophysical computer programs, dat a bases and maps from the United States Geological Survey (USGS)United States Geological Survey (USGS) Open file, No. 95-0077 30p. $ 5.00GlobalComputer, Program -geophysics bibliography
DS200612-0017
2006
Anderson AnalyticsAnderson AnalyticsA diamond is forever - but at what price? determine market value from market data.Anderson Analytics, Feb. 9, 1p.GlobalNews item - diamond price
DS1995-0045
1995
Anderson. R.B.Anderson. R.B., Bone, R.M.First Nations economic development: a contingency perspectiveCanadian Geographer, Vol. 39, No. 2, pp. 120-130.CanadaNative rights, Overview- First Nations
DS2002-0042
2002
Andersson, J.Andersson, J., Moller, C., Johansson, L.Zircon geochronology of migmatite gneisses along the mylonite zone: a major sveconorwegian terrane boundaryPrecambrian Research, Vol. 114, No. 1-2, pp. 121-47.Norway, Baltic ShieldGeochronology, Craton
DS201806-1208
2018
Andersson, M.Andersson, M., Malehmir, A.Internal architecture of the Alno alkaline and carbonatite complex (central Sweden) revealed using 3D models of gravity and magnetic data.Tectonophysics, Vol. 740-741, pp. 53-71.Europe, Swedencarbonatite - Alno
DS200712-0019
2007
Andersson, U.B.Andersson, U.B., Rutanen, HG., Johansson, A., Mansfeld, J., Rimsa, A.Characterization of the Paleoproterozoic mantle beneath the Fennoscandian shield: geochemistry and isotope geology (Nd, Sr) of ~1.8 Ga mafic plutonic rocks ...International Geology Review, Vol. 49, 7, pp. 587-625.Europe, SwedenGeochronology
DS1989-0026
1989
Andi, Z.Andi, Z., Meyer, H.O.A.Inclusions in diamonds from Chinese kimberlitesDiamond Workshop, International Geological Congress, July 15-16th. editors, Poster sessionChinaDiamond inclusions
DS1991-0013
1991
Andi ZhangAlian Wang, Dhamelincourt, P., Lihe Guo, Wuyi Wang, Andi ZhangMicro-structural variations in mantle derived garnetsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 448-450ChinaRaman spectroscopy, Garnets
DS1991-0991
1991
Andi ZhangLihe Guo, Wuyi Wang, Alian Wang, Andi ZhangIR spectroscopic characters of garnets and spinels - a potential discriminative tool for diamond explorationProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 154-156China, Australia, South AfricaSpectroscopy, Chromites
DS1991-1828
1991
Andi ZhangWang Alian, Wuyi Wang, Andi ZhangMicrostructural variations of a pyrope inclusion in diamond as revealed bya micro-Raman spectroscopic studyCanadian Mineralogist, Vol. 29, pp. 517-524ChinaDiamond inclusion, Diamond morphology
DS1985-0309
1985
Andnava, S.J.Johnston, A.,Andnava, S.J.Recurrence Rates and Probability Estimates for the New Madrid Seismic Zone.Journal of Geophysical Research, Vol. 90, No. B5, JULY 10TH. PP. 6737-6753.United States, Central States, Gulf Coast, Arkansas, Missouri, TennesseeMidcontinent, Mississippi Embayment, Tectonics
DS1983-0154
1983
Ando, C.Brown, L., Ando, C., Klemperer, J., Oliver, J.A., Kaufman, S. C.Adirondack Appalachian Crustal Structure: the Cocorp Northeast Traverse.Geological Society of America (GSA) Bulletin., Vol. 94, No. 10, OCTOBER PP. 1173-1184.GlobalMid Continent
DS1983-0358
1983
Ando, C.Klemperer, S.L., Brown, L., Czuchra, B., Ando, C.Cocorp Seismic Reflection Profiling in the Grenville Age Adirondack Mountains, New York State: Results and Geologic Implications.Geological Society of America (GSA), Vol. 15, No. 6, P. 615. (abstract.).GlobalMid Continent
DS1984-0016
1984
Ando, C.J.Ando, C.J., Czuchra, B.L., Klemperer, S.L., Brown, L.D.Crustal Profile of Mountain Belt: Cocorp Deep Seismic ReflecAmerican Association of Petroleum Geologists, Vol. 68, No. 7, JULY, PP. 819-837.Appalachia, New Hampshire, VermontMid-continent
DS2001-0028
2001
Ando, J.Ando, J., Shibata, Okajima, Kanagawa, Furosho, TomiolaStriped iron zoning of olivine induced discloaction creep in deformed peridotitesNature, No. 6866, Dec. 20, pp. 893-4.MantlePeridotites
DS200812-1288
2008
Ando, J-i.Yamamoto, J., Ando, J-i., Kagi, H., Inoue, T., Yamada, A., Yamazaki, D., Irifune, T.In situ strength measurements on natural upper mantle minerals.Physics and Chemistry of Minerals, Vol. 35, pp. 249-257.MantleRheology, geocbarometry
DS201112-0506
2011
Ando, J-I.Katayama, I., Michibayashi, K., Terao, R., Ando, J-I., Komiya, T.Water content of the mantle xenoliths from Kimberley and implications for explaining textural variations in cratonic roots.Geological Journal, Vol. 46, pp. 173-182.Africa, South AfricaSpectroscopy, microstructures
DS201412-0274
2014
Ando, S.Garzanti, E., Resentini, A., Ando, S., Vezzoli, G., Pereira, A., Vermeesch, P.Physical controls on sand and composition and relative durability of detrital minerals during ultra-long distance littoral and aeolian transport ( Namibia and southern Angola).Sedimentology, Vol. 62, 4, pp. 971-996.Africa, Namibia, AngolaDiamondiferous littoral deposits
DS201802-0238
2018
Ando, S.Garzanti, E., Dinis, P., Vermeesch, P., Ando, S., Hahn, A., Huvi, J., Limonta, M., Padoan, M., Resentini, A., Rittner, M., Vezzoli, G.Sedimentary processes controlling ultralong cells of littoral transport: placer formation and termination of the Orange sand highway in southern Angola.Sedimentology, Vol. 65, 2, pp. 431-460.Africa, Angolaplacers, alluvials

Abstract: This study focuses on the causes, modalities and obstacles of sediment transfer in the longest cell of littoral sand drift documented on Earth so far. Sand derived from the Orange River is dragged by swell waves and persistent southerly winds to accumulate in four successive dunefields in coastal Namibia to Angola. All four dunefields are terminated by river valleys, where aeolian sand is flushed back to the ocean; and yet sediment transport continues at sea, tracing an 1800 km long submarine sand highway. Sand drift would extend northward to beyond the Congo if the shelf did not become progressively narrower in southern Angola, where drifting sand is funnelled towards oceanic depths via canyon heads connected to river mouths. Garnet-magnetite placers are widespread along this coastal stretch, indicating systematic loss of the low-density feldspatho-quartzose fraction to the deep ocean. More than half of Moçamedes Desert sand is derived from the Orange River, and the rest in similar proportions from the Cunene River and from the Swakop and other rivers draining the Damara Orogen in Namibia. The Orange fingerprint, characterized by basaltic rock fragments, clinopyroxene grains and bimodal zircon-age spectra with peaks at ca 0•5 Ga and ca 1•0 Ga, is lost abruptly at Namibe, and beach sands further north have abundant feldspar, amphibole-epidote suites and unimodal zircon-age spectra with a peak at ca 2•0 Ga, documenting local provenance from Palaeoproterozoic basement. Along with this oblique-rifted continental margin, beach placers are dominated by Fe-Ti-Cr oxides with more monazite than garnet and thus have a geochemical signature sharply different from beach placers found all the way along the Orange littoral cell. High-resolution mineralogical studies allow us to trace sediment dispersal over distances of thousands of kilometres, providing essential information for the correct reconstruction of ‘source to sink’ relationships in hydrocarbon exploration and to predict the long-term impact of man-made infrastructures on coastal sediment budgets.
DS200612-0631
2006
Andonikov, A.V.Jacob, D.E., Foley, S.F., Andonikov, A.V.Re-enrichment of cratonic lithospheric mantle beneath an evolving rift: mantle xenoliths from East Antarctica.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 285. abstract only.AntarcticaXenolith - geochemistry
DS1900-0086
1902
Andrade, A. De.Andrade, A. De.The Diamond and GoldGeorgetown, Demerara: G.a. Packwood., 27P.South America, VenezuelaKimberlite, Guidebook, Kimberley, Mazaruni River
DS1940-0160
1948
Andrade, C.F.Andrade, C.F.Diamond Deposits in LundaInternational Geological Congress 18TH., PT. 14, P. 225.Angola, West AfricaGeology
DS1950-0118
1953
Andrade, C.F.Andrade, C.F.Diamond Deposits in Lunda. a Geological Survey Made in 1945-1946. a Study Made of the Diamondiferous Gravels and Concentrates.Comp. Diamantes De Angola Serv. Cult., No. 17, PT. 1, 151P.; PT 2, 224P.AngolaAlluvial Placer Deposits
DS1950-0164
1954
Andrade, C.F.Andrade, C.F.On the Age of the So Called 'lunda Stage ' in the Diamandiferous Region of Northern Angola.Geological Society PORTUGAL BOL., Vol. 11, PP. 69-74.Angola, West AfricaGeology, Geochronology
DS1997-0030
1997
Andrade, F.R.D.Andrade, F.R.D.Petrology and geochemistry of crustally contaminated komatiitic basalts from Vereny Belt, Baltic shield.Geological Association of Canada (GAC) Abstracts, POSTER.BrazilCarbonatite, Deposit - Barra do Itapirapua
DS1997-0031
1997
Andrade, F.R.D.Andrade, F.R.D., Bau, M., Duiski, P.Zirconium and hafnium in carbonatites: a re-evaluationGeological Association of Canada (GAC) Abstracts, GlobalCarbonatite
DS1999-0011
1999
Andrade, F.R.D.Andrade, F.R.D., Moller, P., Gilg, H.A.Hydrothermal rare earth elements mineralization in the Barra do Itapirapuacarbonatite, trace elements and C, OChemical Geology, Vol. 155, No. 1-2, Mar. 1, pp. 91-114.Brazilrare earth elements (REE), inclusions, Carbonatite
DS1999-0012
1999
Andrade, F.R.D.Andrade, F.R.D., Moller, P., Hohndorf, A.The effect of hydrothermal alteration Strontium neodymium isotopic signatures of the Barra do Itapirapua carbonatiteJournal of Geology, Vol. 107, No. 2, Mar. pp. 177-92.BrazilGeochronology, Carbonatite
DS2000-0842
2000
Andrade, F.R.D.Ruberti, E., Andrade, F.R.D.Mineral chemistry evidence of magmatic evolution in the Barra do Itapirapua carbonatite, southern Brasil.Igc 30th. Brasil, Aug. abstract only 1p.BrazilCarbonatite
DS201112-0174
2009
Andrade, K.W.Chaves, M.L.D.C., Andrade, K.W., Moiera, L.A.The diamond bearing Abel Regis intrusion (Carmo do Paranaiba, MG) : kimberlite or lamproite?REM Revista Escola de Minas, Vol. 62, 4, pp. 431-438.South America, Brazil, Minas GeraisDeposit - Abel Regis
DS201412-0009
2014
Andrade, K.W.Andrade, K.W., Chaves, M.L.S.C.Piropos kimberlticos da provincia diamantifera Serra da Canastra ( MG): importancia na prospecccao de intrusoes ferties.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 4p. AbstractSouth America, Brazil, Minas GeraisDeposit - Canastra area
DS201412-0158
2014
Andrade, K.W.Da Silva, M.C.R., Chaves, M.L.S.C., Andrade, K.W.Sistemas deposicionais tratos de sistemas e a mineralizacao em diamantes da formacao Sopa-Brumadinho na regiiao de Diamantin a ( MG).6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractSouth America, Brazil, Minas GeraisDeposit - Diamantina
DS201603-0364
2011
Andrade, K.W.Andrade, K.W., de Sa Carneiro Chaves, M.L.Geologia e mineralogia do kimberlito Grota do Cedro ( Coromandel, MG).Geonomos *** IN POR, Vol. 19, 1, pp. 39-45. *** In PortugueseSouth America, BrazilDeposit - Coromandel area

Abstract: Hundreds of kimberlite intrusions and related rocks are known in the Coromandel region (MG), in the "Alto Paranaiba Diamondiferous Province", although the knowledge of these rocks is still scarce. Among these intrusions, it emphasizes the Grota do Cedro kimberlite, which outcrops in the drainage of same name at south of Coromandel (MG), hosted in micaschists of the Araxá Group (Neoproterozoic). The body has a roughly elliptical surface shape with 350 and 300 m axis; its chemical composition is similar to others of the province, and mineral chemistry of Cr-pyrope shows a strong concentration in the "G9" and "G5" fields. These chemical fields generally characterize diamond-poor or infertile intrusions.
DS202008-1378
2020
Andrade, K.W.Chaves, M.L.de Sa.C., Caldas, J.P.de P., Andrade, K.W., Barbosa, M.S.C.Diamonds from the Santo Antonio River ( Delfinopolis Minas Gerais): probable relationship with the Canastra-3 kimberlite.REM, Int. Journal Ouro Preto, Vol. 73, 1, pp. 51-58. pdfSouth America, Brazil, Minas Geraisdeposit - Canastra-3

Abstract: The study identifies the Canastra-3 Kimberlite magnetic anomaly as the likely primary source of the alluvial diamonds recovered by "garimpeiros" in the Santo Antônio River basin (Delfinópolis, southwestern Minas Gerais). This conclusion is based on cumulative geophysical, hydrographic, metallogenical and mineral geochemistry evidences. The study area is located within fertile ground in the border of the São Francisco craton, close to other diamond primary sources and secondary deposits. This kimberlitic target is the only known in the Santo Antônio River basin. In addition, the known mineralized gravels of this river, worked in the past by "garimpeiros", have evidence of a short transport (angular pebbles and blocks), further evidence of a nearby source. The original data collected in the "Minas Gerais Aerogeophysical Survey Program" was processed and analyzed with the Euler Deconvolution method, implemented in software Oasis Montaj. With the exception of the Canastra-3 body anomaly, all others in the study were classified as non-kimberlitic. Recent sampling work on the weathered top of the Canastra-3 Kimberlite recovered indicator minerals, notably a high proportion of pyrope garnets of the G-10 type, which is unusual among the kimberlites of the region.
DS201503-0160
2015
Andrade, M.B.Menezes Filho, L.A.D., Atencio, D., Andrade, M.B., Downs, R.T., Chaves, M.L.S.C., Romano, A.W., Scholz, R., Persiano, A.I.C.Pauloabibite, trigonal NaNbO3, isostructural with ilmenite, from the Jacupiranga carbonatite, Cajati, Sao Paulo, Brazil.American Mineralogist, Vol. 100, pp. 442-446.South America, BrazilCarbonatite
DS201906-1278
2019
Andrade, M.B.Broom-Fendley, S., Smith, M., Andrade, M.B., Ray, S., Banks, D.A., Loye, E., Atencio, D., Pickles, J.R., Wall, F.Sulphate bearing monazite (Ce) from silicified dolomite carbonatite, Eureka, Namibia: substitution mechanisms, redox state and HREE enrichment.3rd International Critical Metals Meeting held Edinburgh, 1p. Abstract p. 51.Africa, Namibiadeposit - Eureka
DS202003-0332
2020
Andrade, M.B.Broom-Fendley, S., Smith, M.P., Andrade, M.B., Ray, S., Banks, D.A., Loye, E., Antencio, D., Pickles, J.P., Wall, F.Sulfur bearing monzazite (Ce) from the Eureka carbonatite, Namibia: oxidation state, substitution mechanism, and formation conditions.Mineralogical Magazine, pp. 1-14, pdfAfrica, Namibiacarbonatite, REE

Abstract: Sulfur-bearing monazite-(Ce) occurs in silicified carbonatite at Eureka, Namibia, forming rims up to ~0.5 mm thick on earlier-formed monazite-(Ce) megacrysts. We present X-ray photoelectron spectroscopy data demonstrating that sulfur is accommodated predominantly in monazite-(Ce) as sulfate, via a clino-anhydrite-type coupled substitution mechanism. Minor sulfide and sulfite peaks in the X-ray photoelectron spectra, however, also indicate that more complex substitution mechanisms incorporating S2 and S4+ are possible. Incorporation of S6+ through clino-anhydrite-type substitution results in an excess of M2+ cations, which previous workers have suggested is accommodated by auxiliary substitution of OH for O2. However, Raman data show no indication of OH, and instead we suggest charge imbalance is accommodated through F substituting for O2. The accommodation of S in the monazite-(Ce) results in considerable structural distortion that may account for relatively high contents of ions with radii beyond those normally found in monazite-(Ce), such as the heavy rare earth elements, Mo, Zr and V. In contrast to S-bearing monazite-(Ce) in other carbonatites, S-bearing monazite-(Ce) at Eureka formed via a dissolutionprecipitation mechanism during prolonged weathering, with S derived from an aeolian source. While large S-bearing monazite-(Ce) grains are likely to be rare in the geological record, formation of secondary S-bearing monazite-(Ce) in these conditions may be a feasible mineral for dating palaeo-weathering horizons.
DS201709-2043
2017
Andrade, N.F.Pimenta Martins, L.G., Matos, M.J.S., Paschoal, A.R., Freire, P.T.C., Andrade, N.F., Aguiar, A.L., Kong, J., Neves, B.R.A., de Oliveira, A.B., Mazzoni, M.S.C., Souza Filhio, A.G., Cancad, L.G.Raman evidence for pressure induced formation of diamondene.Nature Communications, Vol. 8, 9p.Technologydiamondene

Abstract: Despite the advanced stage of diamond thin-film technology, with applications ranging from superconductivity to biosensing, the realization of a stable and atomically thick two-dimensional diamond material, named here as diamondene, is still forthcoming. Adding to the outstanding properties of its bulk and thin-film counterparts, diamondene is predicted to be a ferromagnetic semiconductor with spin polarized bands. Here, we provide spectroscopic evidence for the formation of diamondene by performing Raman spectroscopy of double-layer graphene under high pressure. The results are explained in terms of a breakdown in the Kohn anomaly associated with the finite size of the remaining graphene sites surrounded by the diamondene matrix. Ab initio calculations and molecular dynamics simulations are employed to clarify the mechanism of diamondene formation, which requires two or more layers of graphene subjected to high pressures in the presence of specific chemical groups such as hydroxyl groups or hydrogens.
DS201112-0253
2010
Andrade, S.De Assis Janasi, V., Andrade, S., Svisero, D.P.,Vieira de Almeida, V.Inferencias sobre a evolucao petrologica do manto no sudeste brasileiro a partir de microanalises de elementos traco em piroxenios e olivin a de xenolitos de espinelio peridotitos.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 85.South America, BrazilPetrology of pyroxenes, olivines in xenoliths
DS202003-0371
2020
Andraught, D.Xie, L. , Yoneda, A., Andraught, D.Formation of bridgmanite-enriched layer at the top lower-mantle during magma ocean solificiation.Nature Communications, Vol. 11, pp. 1-10.Mantlebridgmanite

Abstract: Thermochemical heterogeneities detected today in the Earth’s mantle could arise from ongoing partial melting in different mantle regions. A major open question, however, is the level of chemical stratification inherited from an early magma-ocean (MO) solidification. Here we show that the MO crystallized homogeneously in the deep mantle, but with chemical fractionation at depths around 1000?km and in the upper mantle. Our arguments are based on accurate measurements of the viscosity of melts with forsterite, enstatite and diopside compositions up to ~30?GPa and more than 3000?K at synchrotron X-ray facilities. Fractional solidification would induce the formation of a bridgmanite-enriched layer at ~1000?km depth. This layer may have resisted to mantle mixing by convection and cause the reported viscosity peak and anomalous dynamic impedance. On the other hand, fractional solidification in the upper mantle would have favored the formation of the first crust.
DS201012-0323
2010
AndraultJavoy, M., Kaminski, E., Guyot,Andrault, Sanloup, Moreira, Labrosse, Jambon, Agrinier.Davaille, JaupartThe chemical composition of the Earth: enstatite chondrite models.Earth and Planetary Science Letters, Vol. 293, 3-4, pp. 259-268.MantleChemistry
DS2001-0029
2001
Andrault, D.Andrault, D.Evaluation of (magnesium, iron) partitioning between silicate perovskite and magnesiowustite up to 120 GPa and 2300KJournal of Geophysical Research, Vol. 106, No.2, Feb.10, pp. 2079-88.MantlePerovskite
DS2001-0030
2001
Andrault, D.Andrault, D., Bolfan-Casanova, N., Guignot, N.Equation of state of lower mantle ( Al Fe MgSiO3) perovskiteEarth and Planetary Science Letters, Vol. 193, No. 3-4, pp.501-8.MantleGeochemistry, Perovskite
DS2002-0043
2002
Andrault, D.Andrault, D., Bolfan-Casanova, N., Guignot, N.Effect of aluminum on lower mantle mineralogy18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.76.MantleUHP mineralogy - perovskite
DS2003-0019
2003
Andrault, D.Andrault, D., Angel, R.J., Mosenfelder, J.L., LeBihan, T.Equation of state of stishovite to lower mantle pressuresAmerican Mineralogist, Vol. 88, 2,3pp. 301-7.MantleMineralogy
DS200612-1213
2005
Andrault, D.Samuel, H., Farnetani, C.G., Andrault, D.Heterogeneous lowermost mantle: compositional constraints and seismological observables.American Geophysical Union, Geophysical Monograph, Ed. Van der Hilst, Earth's Deep Mantle, structure ...., No. 160, pp. 101-116.MantleGeophysics - seismics
DS200712-0020
2007
Andrault, D.Andrault, D.Properties of lower mantle Al-(Mg,Fe)SiO3 perovskite.Ohtani: Advances in high pressure mineralogy, pp. 15-36.MantleMineralogy
DS200712-0353
2006
Andrault, D.Gautron, L., Greaux, S., Andrault, D., Bolfan Casanova, N., Guignot,N., Bouhifd, M.A.Uranium in the Earth's lower mantle.Geophysical Research Letters, Vol. 33, 23, Dec. 16, L23301MantleUranium
DS200812-0346
2008
Andrault, D.Fialin, M., Catillon, G., Andrault, D.Disproportionation of Fe 2+ in Al free silicate perovskite in the laser heated diamond anvil cell as recorded by electron probe microanalysis of oxygen.Physica and Chemistry of Minerals, In press available 9p.MantlePerovskite
DS201012-0007
2010
Andrault, D.Andrault, D., Munoz, M., Bolfan-Casanova, N., Guigot, N., Schouten, J-P.Experiment evidence for perovskite and post perovskite coexistence throughout the whole 'D' region.Earth and Planetary Science Letters, Vol. 293, 1-2, pp. 90-96.MantleBoundary
DS201012-0008
2010
Andrault, D.Andrault, D., Nigro, G., Bolfan-Casanova, N., Bouhifd, M.A., Garbarino, G., Mezouar, M.Melting curve of the lowermost Earth's mantle.Goldschmidt 2010 abstracts, abstractMantleMelting
DS201112-0020
2011
Andrault, D.Andrault, D., Bolfan-Casanova, N., loNigro, G., Bouhifd, M.A., Garbarino, G., Mezouar, M.Solidus and liquidus profiles of chrondritic mantle: implications for melting of the Earth across its history.Earth and Planetary Science Letters, Vol. 304, 1-2, pp. 251-259.MantleMelting
DS201112-0021
2011
Andrault, D.Andrault, D., Lo Nigro, G., Bolfan-Casanova, N., Bouhifd, M.A., Garbarino, G., Mezouar, M.Melting properties of chronditic mantle to the core mantle boundary.Goldschmidt Conference 2011, abstract p.438.MantleMelting
DS201112-0408
2011
Andrault, D.Hammouda, T., Andrault, D., Koga, K., Katsura, T., Martin, M.Ordering in double carbonates and implications for processes at subduction.Contributions to Mineralogy and Petrology, Vol. 161, 3, pp. 439-450.MantleSubduction
DS201312-0089
2013
Andrault, D.Bouhifd, M.A., Andrault, D., Bolfan-Casanova, N.Thermodynamics of lower mantle minerals.Goldschmidt 2013, AbstractMantleMineralogy
DS201412-0010
2014
Andrault, D.Andrault,D., Pesce, G., Ali Bouhifd, M., Bolfan-Casanova, N., Henot, J-M., Mezouar, M.Melting of basalt at the core-mantle boundary.Science, Vol. 344, no. 6186, pp. 892-895.MantleSubduction
DS201503-0135
2015
Andrault, D.Bouhifd, M.A., Boyet, M., Cartier, C., Hammouda, T., Bofan-Casanova, N., Devidal, J.L., Andrault, D.Superchondritic Sm/Nd ratio of the Earth: impact of Earth's core formation.Earth and Planetary Science Letters, Vol. 413, March 1, pp. 158-166.MantleGeochronology

Abstract: This study investigates the impact of Earth's core formation on the metal-silicate partitioning of Sm and Nd, two rare-earth elements assumed to be strictly lithophile although they are widely carried by the sulphide phases in reducing material (e.g. enstatite chondrites). The partition coefficients of Sm and Nd (DSmDSm and DNdDNd) between molten CI and EH chondrites model compositions and various Fe-rich alloys (in the Fe-Ni-C-Si-S system) have been determined in a multi-anvil between 3 and 26 GPa at various temperatures between 2073 and 2440 K, and at an oxygen fugacity ranging from 1 to 5 log units below the iron-wüstite (IW) buffer. The chemical compositions of the run products and trace concentrations in Sm and Nd elements were determined using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry. Our results demonstrate the non-fractionation of Sm and Nd during the segregation of the metallic phases: the initial Sm/Nd ratio of about 1 in the starting materials yields precisely the same ratio in the recovered silicate phases after the equilibration with the metal phases at all conditions investigated in this study. In addition, DSmDSm and DNdDNd values range between 10?310?3 and 10?510?5 representing a low solubility in the metal. An increase of the partition coefficients is observed with decreasing the oxygen fugacity, or with an increase of S content of the metallic phase at constant oxygen fugacity. Thus, based on the actual Sm and Nd concentrations in the bulk Earth, the core should contain less than 0.4 ppb for Sm and less than 1 ppb for Nd. These estimates are three orders of magnitude lower than what would be required to explain the reported 142Nd excess in terrestrial samples relative to the mean chondritic value, using the core as a Sm-Nd complementary reservoir. In other words, the core formation processes cannot be responsible for the increase of the Sm/Nd ratio in the mantle early in Earth history.
DS201707-1309
2017
Andrault, D.Bouhifd, M.A., Clesi, V., Boujibar, A., Cartier, C., Hammouda, T., Boyet, M., Manthilake, G., Monteux, J., Andrault, D.Silicate melts during the Earth's core formation.Chemical Geology, Vol. 461, pp. 128-139.Mantlemelting

Abstract: Accretion from primordial material and its subsequent differentiation into a planet with core and mantle are fundamental problems in terrestrial and solar system. Many of the questions about the processes, although well developed as model scenarios over the last few decades, are still open and much debated. In the early Earth, during its formation and differentiation into rocky mantle and iron-rich core, it is likely that silicate melts played an important part in shaping the Earth's main reservoirs as we know them today. Here, we review several recent results in a deep magma ocean scenario that give tight constraints on the early evolution of our planet. These results include the behaviour of some siderophile elements (Ni and Fe), lithophile elements (Nb and Ta) and one volatile element (Helium) during Earth's core formation. We will also discuss the melting and crystallization of an early magma ocean, and the implications on the general feature of core-mantle separation and the depth of the magma ocean. The incorporation of Fe2 + and Fe3 + in bridgmanite during magma ocean crystallization is also discussed. All the examples presented here highlight the importance of the prevailing conditions during the earliest time of Earth's history in determining the composition and dynamic history of our planet.
DS201711-2499
2017
Andrault, D.Andrault, D., Bolfan-Casanova, N., Bouhifd, M.A., Boujibar, A., Garbarino, G., Manthilake, G., Mezouar, M., Monteux, J., Parisiades, P., Pesce, G.Toward a coherent model for the melting behaviour of the deep Earth's mantle.Physics of the Earth and Planetary Interiors, Vol. 265, pp. 67-81.Mantlemelting

Abstract: Knowledge of melting properties is critical to predict the nature and the fate of melts produced in the deep mantle. Early in the Earth’s history, melting properties controlled the magma ocean crystallization, which potentially induced chemical segregation in distinct reservoirs. Today, partial melting most probably occurs in the lowermost mantle as well as at mid upper-mantle depths, which control important aspects of mantle dynamics, including some types of volcanism. Unfortunately, despite major experimental and theoretical efforts, major controversies remain about several aspects of mantle melting. For example, the liquidus of the mantle was reported (for peridotitic or chondritic-type composition) with a temperature difference of ?1000 K at high mantle depths. Also, the Fe partitioning coefficient (DFeBg/melt) between bridgmanite (Bg, the major lower mantle mineral) and a melt was reported between ?0.1 and ?0.5, for a mantle depth of ?2000 km. Until now, these uncertainties had prevented the construction of a coherent picture of the melting behavior of the deep mantle. In this article, we perform a critical review of previous works and develop a coherent, semi-quantitative, model. We first address the melting curve of Bg with the help of original experimental measurements, which yields a constraint on the volume change upon melting (?Vm). Secondly, we apply a basic thermodynamical approach to discuss the melting behavior of mineralogical assemblages made of fractions of Bg, CaSiO3-perovskite and (Mg,Fe)O-ferropericlase. Our analysis yields quantitative constraints on the SiO2-content in the pseudo-eutectic melt and the degree of partial melting (F) as a function of pressure, temperature and mantle composition; For examples, we find that F could be more than 40% at the solidus temperature, except if the presence of volatile elements induces incipient melting. We then discuss the melt buoyancy in a partial molten lower mantle as a function of pressure, F and DFeBg/melt. In the lower mantle, density inversions (i.e. sinking melts) appear to be restricted to low F values and highest mantle pressures. The coherent melting model has direct geophysical implications: (i) in the early Earth, the magma ocean crystallization could not occur for a core temperature higher than ?5400 K at the core-mantle boundary (CMB). This temperature corresponds to the melting of pure Bg at 135 GPa. For a mantle composition more realistic than pure Bg, the right CMB temperature for magma ocean crystallization could have been as low as ?4400 K. (ii) There are converging arguments for the formation of a relatively homogeneous mantle after magma ocean crystallization. In particular, we predict the bulk crystallization of a relatively large mantle fraction, when the temperature becomes lower than the pseudo-eutectic temperature. Some chemical segregation could still be possible as a result of some Bg segregation in the lowermost mantle during the first stage of the magma ocean crystallization, and due to a much later descent of very low F, Fe-enriched, melts toward the CMB. (iii) The descent of such melts could still take place today. There formation should to be related to incipient mantle melting due to the presence of volatile elements. Even though, these melts can only be denser than the mantle (at high mantle depths) if the controversial value of DFeBg/melt is indeed as low as suggested by some experimental studies. This type of melts could contribute to produce ultra-low seismic velocity anomalies in the lowermost mantle.
DS201803-0432
2018
Andrault, D.Andrault, D., Pesce, G., Manthilake, G., Monteux, J., Volfan-Casanova, N., Chantel, J. , Novella, D., Guignot, N., King, A., Itie, J-P., Hennet, L.An archean mushy mantle.Nature Geoscience, Vol. 11, 2, pp. 85-86.Mantlegeodynamics

Abstract: Experimental data reveal that Earth’s mantle melts more readily than previously thought, and may have remained mushy until two to three billion years ago.
DS1984-0017
1984
Andrawes, F.Andrawes, F., et al.Gas Chromatographic Anlysis of Volatiles in Fluid and Gas InclusionsJournal of Chromotography, Vol. 302, pp. 181-93.GlobalDiamond Inclusions
DS1984-0018
1984
Andrawes, F.Andrawes, F., Holzer, G., Roedder, E., Gibson, E.K., Oro, J.Gas Chromatographic Analysis of Volatiles in Fluid and Gas Inclusions.Journal of Chromatography, Vol. 302, PP. 181-193.GlobalFluid Inclusions, Diamonds, Geochemistry
DS1998-0667
1998
AndreIvanov, A.V., Rasskazov, Boven, Andre, Maslovskya, TemuLate Cenozoic alkaline ultrabasic and alkaline basanite magmatism of the Rung we Province, TanzaniaPetrology, Vol. 6, No. 3, June, pp. 208-229.RussiaAlkaline rocks, Brief overview
DS1910-0001
1910
Andre, F.Andre, F.Die Rechsverhaltnisse im Pomona GebietBerlin: D. Reimer., 67P.Southwest Africa, NamibiaMining, Prospecting
DS1986-0179
1986
Andre, L.Demulder, M., Hertogen, J., Deutsch, S., Andre, L.The role of crustal contamination in the potassic suite of theKarisimbi volcano (Virunga) African rift valleyChemical Geology, Vol. 57, No. 1-2, Dec. 15, pp. 117-136AfricaTectonics, Mantle genesis
DS1995-0490
1995
Andre, L.Elfadili, S., Demaiffe, D., Andre, L.Origin of eclogite nodules from the Mbuji Mayi kimberlite (Kasai):subducted ancient oceanic crustProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 146-8.Democratic Republic of CongoEclogite, subduction, Deposit -Mbuji Mayi
DS1995-1824
1995
Andre, L.Stein, G., Andre, L.Zirconium/Hafnium and Niobium/Tantalum fractionations in intraplate basaltic rocks and carbonatites: new constraints on mantle evolution.Terra Nova, Abstract Vol., p. 296.GlobalCarbonatite
DS1998-0029
1998
Andre, L.Andre, L., Shatsky, V.S., De Corte, K., Sobolev, N.V.Potassium rich clinopyroxenes as mantle conveyers of crustal derived components.7th International Kimberlite Conference Abstract, pp. 17-19.Australia, RussiaMicroanalyses - omphacite, clinopyroxene, Deposit - Argyle, Kochetav Massif
DS1998-0052
1998
Andre, L.Ashchepkov, I.V., Salters, V.J.R., Andre, L.Relationships between garnet and clinopyroxene in Vitim mantle xenoliths:evidence of polystage growth and melt7th International Kimberlite Conference Abstract, pp. 35-36.RussiaXenoliths - lherzolites, Geochemistry
DS1998-0339
1998
Andre, L.Demaiffe, D., El Fadili, S., Andre, L.Geochemical and isotopic (Strontium, neodymium) study of eclogite nodules from the Mbuji Mayi kimberlites, Kasai, Congo.7th International Kimberlite Conference Abstract, pp. 190-192.GlobalGeochemistry, Deposit - Mbuji Mayi
DS2001-0057
2001
Andre, L.Ashchepkov, I.V., Travin, S.V., Andre, L., KhmeinikovaCenozoic flood basalt volcanism, mantle xenoliths and melting regions in the lithospheric mantle Baikal Rift.Alkaline Magmatism -problems mantle source, pp. 204-15.Globalvolcanism - basalt
DS2002-0068
2002
Andre, L.Aschepkov, I.V., Andre, L.Pyroxenite xenoliths in picrite basalts ( Vitim Plateau) origin and differentiation of mantle melts.Russian Geology and Geophysics, Vol. 43, 3-4, pp. 328-47.RussiaPicrites
DS2003-0293
2003
Andre, L.Coussaert, N., Mercier, J-C., Demaiffe, D., Andre, L.Equilibrium conditions revisited for Lesotho kimberlites8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, AbstractLesothoMantle petrology, Pyroxene geothermometry
DS200412-0379
2003
Andre, L.Coussaert, N., Mercier, J-C., Demaiffe, D., Andre, L.Equilibrium conditions revisited for Lesotho kimberlites.8 IKC Program, Session 6, AbstractAfrica, LesothoMantle petrology, pyroxxene geothermometry
DS200612-0024
2006
Andre, L.Andre, L., Cardinal, D., Alleman, L.Y., Moorbath, S.Silicon isotopes in ~3.8 Ga West Greenland rocks as clues to the Eoarchean supracrustal Si cycle.Earth and Planetary Science Letters, Vol. 245, 1-2, pp. 162-173.Europe, GreenlandGeochronology, silica
DS201112-0034
2011
Andre, L.Ashchepkov, I.V., Andre, L., Downes, H., Belyatsky, B.A.Pyroxenites and megacrysts from Vitim picrite basalts ( Russia): polybaric fractionation of rising melts in the mantle?Journal of Asian Earth Sciences, Vol. 42, 1-2, pp. 14-37.RussiaPicrite
DS201511-1830
2015
Andre, L.Decree, S., Boulvais, P., Tack, L., Andre, L., Baele, J-M.Fluorapatite in carbonatite-related phosphate deposits: the case of the Matongo carbonatite. ( Burundi)Mineralium Deposita, in press available 14p.Africa, BurundiCarbonatite

Abstract: The Matongo carbonatite intrusive body in the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC) in Burundi is overlain by an economic phosphate ore deposit that is present as breccia lenses. The ore exhibits evidence of supergene enrichment but also preserves textures related to the concentration of fluorapatite in the carbonatitic system. Magmatic fluorapatite is abundant in the ore and commonly occurs as millimeter-sized aggregates. It is enriched in light rare earth elements (LREE), which is especially apparent in the final generation of magmatic fluorapatite (up to 1.32 wt% LREE2O3). After an episode of metasomatism (fenitization), which led to the formation of K-feldspar and albite, the fluorapatite-rich rocks were partly brecciated. Oxygen and carbon isotope compositions obtained on the calcite forming the breccia matrix (?18O?=?22.1?- and ?13C?=??1.5?‰) are consistent with the involvement of a fluid resulting from the mixing of magmatic-derived fluids with a metamorphic fluid originating from the country rocks. In a subsequent postmagmatic event, the carbonates hosting fluorapatite were dissolved, leading to intense brecciation of the fluorapatite-rich rocks. Secondary carbonate-fluorapatite (less enriched in LREE with 0.07-0.24 wt% LREE2O3 but locally associated with monazite) and coeval siderite constitute the matrix of these breccias. Siderite has ?18O values between 25.4 and 27.7?- and very low ?13C values (from ?12.4 to ?9.2?, which are consistent with the contribution of organic-derived low ?13C carbon from groundwater. These signatures emphasize supergene alteration. Finally, the remaining voids were filled with a LREE-poor fibrous fluorapatite (0.01 wt% LREE2O3), forming hardened phosphorite, still under supergene conditions. Pyrochlore and vanadiferous magnetite are other minerals accumulated in the eluvial horizons. As a consequence of the supergene processes and fluorapatite accumulation, the phosphate ore, which contains 0.72 to 38.01 wt% P2O5, is also enriched in LREE (LaN/YbN from 47.1 to 83.5; ?REE between 165 and 5486 ppm), Nb (up to 656 ppm), and V (up to 1232 ppm). In the case of phosphate exploitation at Matongo, REE could prove to have a subeconomic potential to be exploited as by-products of phosphates.
DS201601-0013
2015
Andre, L.Decree, S., Boulvais, P., Tack, L., Andre, L., Baele, J-M.Fluorapatite in carbonatite related phosphate deposits: the case for the Matongo carbonatite ( Burundi).Mineralogy and Petrology, in press available, 17p.Africa, BurundiCarbonatite

Abstract: The Matongo carbonatite intrusive body in the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC) in Burundi is overlain by an economic phosphate ore deposit that is present as breccia lenses. The ore exhibits evidence of supergene enrichment but also preserves textures related to the concentration of fluorapatite in the carbonatitic system. Magmatic fluorapatite is abundant in the ore and commonly occurs as millimeter-sized aggregates. It is enriched in light rare earth elements (LREE), which is especially apparent in the final generation of magmatic fluorapatite (up to 1.32 wt% LREE2O3). After an episode of metasomatism (fenitization), which led to the formation of K-feldspar and albite, the fluorapatite-rich rocks were partly brecciated. Oxygen and carbon isotope compositions obtained on the calcite forming the breccia matrix (?18O?=?22.1?‰ and ?13C?=??1.5?‰) are consistent with the involvement of a fluid resulting from the mixing of magmatic-derived fluids with a metamorphic fluid originating from the country rocks. In a subsequent postmagmatic event, the carbonates hosting fluorapatite were dissolved, leading to intense brecciation of the fluorapatite-rich rocks. Secondary carbonate-fluorapatite (less enriched in LREE with 0.07-0.24 wt% LREE2O3 but locally associated with monazite) and coeval siderite constitute the matrix of these breccias. Siderite has ?18O values between 25.4 and 27.7?‰ and very low ?13C values (from ?12.4 to ?9.2?‰), which are consistent with the contribution of organic-derived low ?13C carbon from groundwater. These signatures emphasize supergene alteration. Finally, the remaining voids were filled with a LREE-poor fibrous fluorapatite (0.01 wt% LREE2O3), forming hardened phosphorite, still under supergene conditions. Pyrochlore and vanadiferous magnetite are other minerals accumulated in the eluvial horizons. As a consequence of the supergene processes and fluorapatite accumulation, the phosphate ore, which contains 0.72 to 38.01 wt% P2O5, is also enriched in LREE (LaN/YbN from 47.1 to 83.5; ?REE between 165 and 5486 ppm), Nb (up to 656 ppm), and V (up to 1232 ppm). In the case of phosphate exploitation at Matongo, REE could prove to have a subeconomic potential to be exploited as by-products of phosphates.
DS1997-0266
1997
Andrea, L.Demaiffe, D., Verhulst, A., Andrea, L., Nivin, V.Geochemical (major and trace elements) and neodymium Strontium isotopic study of the Kovdor carbonatites, Kola Pen.Geological Association of Canada (GAC) Abstracts, Russia, Kola PeninsulaCarbonatite, geochemistry, Deposit - Kovdor
DS200812-0034
2008
Andreasen, R.Andreasen, R., Sharma, M., Subbarao, K.V., Viladkar, S.G.Where on Earth is the enriched Hadean reservoir.Earth and Planetary Science Letters, Vol. 266, 1-2, pp. 14-28.MantleGeochronology
DS2002-1231
2002
Andreasson, P.G.Paulsson, O., Andreasson, P.G.Attempted break up of Rodinia at 850 Ma: geochronological evidence from the Seve-Kalak superterrane, Scandinavian Caledonides.Journal of the Geological Society of London, Vol. 159, 6, pp. 751-62.Scandinavia, Norway, Rodinia, GondwanaTectonics - rifting, geochronology
DS2002-1232
2002
Andreasson, P.G.Paulsson, O., Andreasson, P.G.Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seven Kalak superterrane, Scandinavian Caledonides.Journal of the Geological Society of London, Vol. 159, 6, pp. 751-761.Greenland, ScandinaviaBlank
DS200412-1507
2002
Andreasson, P.G.Paulsson, O., Andreasson, P.G.Attempted break-up of Rodinia at 850 Ma: geochronological evidence from the Seven Kalak superterrane, Scandinavian Caledonides.Journal of the Geological Society, Vol. 159, 6, pp. 751-761.Europe, Greenland, FennoscandiaGeochronology
DS200912-0356
2009
Andreazza, P.Kaminsky, F.V., Khachatryan, G.K., Andreazza, P., Araujo, D., Griffin, W.L.Super deep diamonds from kimberlites in the Juin a area, Mato Grosso State, Brazil.Lithos, Vol. 1125, pp. 833-842.South America, Brazil, Mato GrossoDiamond inclusions
DS200912-0357
2009
Andreazza, P.Kaminsky, F.V., Sablukov, S.M., Belousova, E.A., Andreazza, P., Tremblay, M., Griffin, W.L.Kimberlite sources of super deep diamonds in the Juin a area, Mato Grosso State, Brazil.Lithos, In press available,South America, Brazil, Mato GrossoKimberlite genesis
DS201012-0341
2010
Andreazza, P.Kaminsky, F.V., Sablukov, S.M., Belousova, E.A., Andreazza, P., Tremblay, M., Griffin, W.L.Kimberlitic sources of super deep diamonds in the Juin a area, Mato Grosso State, Bahia.Lithos, Vol. 114, pp. 16-29.South America, Brazil, Mato GrossoChapadao, Padrea
DS201012-0721
2010
AndreevSmelov, A.P., Andreev, Altukhova, Babushkin, Bekrenev, Zaitsev.Izbekov, Koroleva, Mishmin, Okrugin, OleinkovKimberlites of the Manchary pipe: a new kimberlite field in central Yakutia.Russian Geology and Geophysics, Vol. 51, pp. 121-126.Russia, YakutiaDeposit - Manchary
DS1988-0012
1988
Andreev, A.V.Andreev, A.V.Role of the metal-graphite (diamond) interface in the mechanism of diamond synthesis.(Russian)Sverkhtverd. Mater., (Russian), No. 5, pp. 5-9RussiaDiamond synthesis
DS1988-0254
1988
Andreev, A.V.Getman, A.F., Andreev, A.V., Vityuk, V.I.Preparation of diamonds from various carbonaceous materials in the presence of metallic melts.(Russian)Sverkhtverd. Mater., (Russian), No. 6, pp. 6-8GlobalDiamond synthesis
DS2002-0044
2002
Andreev, G.V.Andreev, G.V., Posokhov, V.F.Rb Sr age of metasomatic rocks from the southern Saku Massif of alkaline rocksGochemistry International, Vol.40, 3, pp.306-8.RussiaGeochronology, Alkaline rocks, rubidium, strontium, stable isotope geochronology
DS2002-0045
2002
Andreev, G.V.Andreev, G.V., Posokohov, V.F.Rb Sr age of metasomatic rocks from the southern Saku Massif of alkaline rocksGeochemistry International, Vol.40,3,pp.306-8., Vol.40,3,pp.306-8.RussiaAlkaline rocks, Saku Massif
DS2002-0046
2002
Andreev, G.V.Andreev, G.V., Posokohov, V.F.Rb Sr age of metasomatic rocks from the southern Saku Massif of alkaline rocksGeochemistry International, Vol.40,3,pp.306-8., Vol.40,3,pp.306-8.RussiaAlkaline rocks, Saku Massif
DS1950-0363
1958
Andreev, V.V.Andreev, V.V.Almazy Rynok Kapitalistichesnikh StranMoscow: Vneshtorgizdat., 150P.RussiaKimberlite, Diamond, Market, Kimberley
DS1998-1176
1998
AndreevaPokrovskii, B.G., Andreeva, Vrublevskii, GrinevContamination mechanisms of alkaline gabbroid intrusions in the southern framing of Siberian PlatformPetrology, Vol. 6, No. 3, June, pp. 230-236.Russia, SiberiaGeochronology, Alkaline rocks
DS200512-0021
2003
Andreeva, A.Andreeva, A., Kovalenko, V.I.Magma compositions and genesis of the rocks of the Mushugai Khuduk carbonatite bearing alkalic complex ( southern Mongolia): evidence from melt inclusions.Periodico di Mineralogia, (in english), Vol. LXX11, 1. April, pp. 95-105.Asia, MongoliaAlkaline rocks, magmatism
DS201012-0009
2010
Andreeva, I.Andreeva, I., Kovalenko, V.Trace elements and volatile components in silicate and silicate salt magmas of the Mushugai Khuduk carbonatite bearing alkaline complex, southern Mongolia.International Mineralogical Association meeting August Budapest, abstract p. 564.Asia, MongoliaCarbonatite
DS1998-0030
1998
Andreeva, I.A.Andreeva, I.A., Naumov, V.B., Kovalenko, V., KononkovaThe chemical composition of melt inclusions in sphene from theralites Of the Mushugai Khudak carbonatite...Doklady Academy of Sciences, Vol. 361, No. 5, pp. 708-12.GlobalCarbonatite - genesis
DS1998-0031
1998
Andreeva, I.A.Andreeva, I.A., Naumov, V.B., Kovalenko, V.I., KononkovaFluoride sulfate and chloride sulfate salt melts of carbonatite bearing complex Mushugai Khudak.Petrology, Vol. 6, No. 3, June, pp. 274-83.GlobalCarbonatite, Deposit - Mushugai Khudak
DS1999-0013
1999
Andreeva, I.A.Andreeva, I.A., Numov, V.B., Kononkova, N.N.The magma composition and genesis of theralite from the Mushugai Khuduk carbonatite bearing complex....Geochemistry International, Vol. 37, No. 8, Aug. pp. 735-49.GlobalCarbonatite
DS2001-0031
2001
Andreeva, I.A.Andreeva, I.A., Kovalenko, V.I., Naummov, V.B.Crystallization conditions, magma compositions, and genesis of silicate rocks Mushugai Khuduk carbonatitePetrology, Vol. 9, No. 6, pp. 489-515.Russia, MongoliaAlkaline complex, Melt inclusions
DS2001-0032
2001
Andreeva, I.A.Andreeva, I.A., Kovalenko, V.I., Naumov, V.B.Crystallization conditions, magma compositions and genesis of silicate rocks of Mushugai Khuduk ...Petrology, Vol. 9, No. 6, pp. 489-515.Mongolia, southernCarbonatite bearing alkalic complex, Melt inclusions - evidence
DS2001-0033
2001
Andreeva, I.A.Andreeva, I.A., Kovalenko, V.I., Naumov, V.B.Crystallization conditions, magma compositions and genesis of silicate rocks Mushugai Khuduk carbonatitePetrology, Vol. 9, No. 6, pp. 489=515.Mongolia, southernMelting, inclusions, Alkalic complex
DS200412-0039
2004
Andreeva, I.A.Andreeva, I.A., Kovalenko, V.I., Kononkova, N.N.Chemical composition of magma ( melt inclusions) of melilite bearing nephelinite from the Belaya Zima carbonatite complex, easteDoklady Earth Sciences, Vol. 394, 1, Jan-Feb. pp. 116-119.RussiaMelilitite
DS200412-0040
2004
Andreeva, I.A.Andreeva, I.A., Kovalenko, V.I., Naumov, V.B., Kononkova, N.N.Composition and formation conditions of silicate and salt magmas forming the garnet syenite porphyries (Sviatonossites) of the cGeochemistry International, Vol. 42, 6, pp. 497-512.Asia, MongoliaCarbonatite, Mushagi-Khudak Complex
DS200612-0025
2006
Andreeva, I.A.Andreeva, I.A., Kovalenko, V.I., Konokova, N.N.Natrocarbonatitic melts of the Bolshaya Tagna massif, the eastern Sayan region.Doklady Earth Sciences, Vol. 408, 4, pp. 542-546.RussiaCarbonatite
DS200912-0006
2009
Andreeva, I.A.Andreeva, I.A., Kovalenko, V.I.Composiitonal characteristics of carbonatite magmas from the Bolshetagninskii Massif, eastern Sayan.alkaline09.narod.ru ENGLISH, May 10, 1p. abstractRussiaCarbonatite
DS201312-0022
2012
Andreeva, I.A.Andreeva, I.A., Nikiforov, A.V.Genesis of magmas of carbonate- bearing ijolites and carbonatites from the Belaya Zima carbonatite complex ( eastern Sayan Russia) dat a from melt inclusion study.Vladykin, N.V. ed. Deep seated magmatism, its sources and plumes, Russian Academy of Sciences, pp. 133-163.RussiaCarbonatite
DS201412-0011
2014
Andreeva, I.A.Andreeva, I.A.Salt (carbonatite) melts of the Bol'shaya Tagna massif, the eastern sayan region: evidence from melt inclusions.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 148-154.RussiaCarbonatite
DS201510-1756
2014
Andreeva, I.A.Andreeva, I.A.Salt ( carbonatite) melts of the Bol'shaya Tagna Massif, the eastern Sayan region: evidence from melt inclusions.Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 148-159.RussiaMineral chemistry
DS201504-0224
2015
Andreeva, M.Yu.Tarakanov, R.Z., Veselov, O.V., Andreeva, M.Yu.The possible boundary of phase transitions at a depth of 350 km in the transition zone between continents and oceans.Doklady Earth Sciences, Vol. 460, 2, pp. 159-162.Russia, Far EastGeophysics - seismics
DS201412-0321
2014
Andre-Mayer, A.S.Groulier, P.A., Andre-Mayer, A.S., Ohnenstetter, D., Zeh, A., Moukhsil, A., Solgadi, F., El Basbas, A.Petrology, geochemistry and age of the Crevier alkaline intrusion.GAC-MAC Annual Meeting May, abstract 1p.Canada, QuebecAlkalic
DS201512-1971
2015
Andre-Mayer, A.S.Solgadi, F., Groulier, P.A, Moukhsil, A., Ohnenstetter, D., Andre-Mayer, A.S., Zeh, A.Nb-Ta-REE mineralization associated with the Crevier alkaline intrusion.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 69-74.Canada, QuebecAlkalic

Abstract: The Crevier alkaline intrusion is in the Grenville Province, north of the Lac Saint-Jean region of Québec (Fig. 1). It covers ~25 km2 (Bergeron, 1980) and intrudes charnockitic suites in the allochthon belt defi ned by Rivers et al. (1989). This intrusion has a U-Pb zircon age of 957.5 ± 2.9 Ma (Groulier et al., 2014) and is oriented N320°, along the axis of crustal weakness known as the Waswanipi-Saguenay corridor (Bernier and Moorhead, 2000). This corridor is related to the Saguenay graben, which hosts the Saint-Honoré (Niobec) Nb-Ta-REE deposit and Montviel REE deposit. The age of the Saint-Honoré carbonatite was estimated at 584 to 650 Ma (K-Ar whole rock; Vallée and Dubuc, 1970; Boily and Gosselin, 2004). The Montviel intrusion has a U-Pb zircon age of 1894 ± 3.5 Ma (David et al., 2006; Goutier, 2006). These crystallization ages are very different and cannot be related to a single event for the injection of alkaline intrusions. As mapped by Bergeron (1980), the Crevier alkaline intrusion is broadly composed of syenite and carbonatite rocks (Fig. 2). The Nb- Ta mineralization consists of pyrochlore hosted by a nepheline syenite dike swarm in the centre of the intrusion. The highest REE concentrations, up to 729 ppm La and 1465 ppm Ce, are at the edge of the Crevier alkaline intrusion (Niotaz sud showing; Fig. 2).
DS200612-0137
2006
Andreoli, M.Bird, P., Ben Avraham, Z., Schubert, G., Andreoli, M., Viola, G.Patterns of stress and strain rate in southern Africa.Journal of Geophysical Research, Vol. 111, B8, August 11, B08402.Africa, South Africa, BotswanaGeophysics
DS200612-0138
2006
Andreoli, M.Bird, P., Ben Avraham, Z., Schubert, G., Andreoli, M., Viola, G.Patterns of stress and strain rate in southern Africa.Journal of Geophysical Research, Vol. 111, B8, B0802.Africa, South AfricaGeophysics - seismics
DS200812-0600
2007
Andreoli, M.Kounov, A., Niedermann, S., De Wit, M.J., Andreoli, M., Erzinger, J.Present denudation rates at selected sections of the South African escarpment and the elevated continental interior based on cosmogenic 3He and 21Ne.South African Journal of Geology, Vol. 110, 2-3, Sept. pp. 235-248.Africa, South AfricaGeomorphology
DS1990-0666
1990
Andreoli, M.A.G.Hart, R.J., Andreoli, M.A.G., Smith, C.B., Otter, M.L., DurrheimUltramafic rocks in the centre of the Vredefort structure (South Africa):possible exposure of the upper mantleChem. Geol, Vol. 83, No. 3/4, June 25, pp. 233-248South AfricaUltramafics, Mantle - Vredefort structure
DS1990-0667
1990
Andreoli, M.A.G.Hart, R.J., Andreoli, M.A.G., Tredoux, M., De Wit, M.J.Geochemistry across an exposed section of Archean crust at Vredefort, SouthAfrica: with implications for mid- crustal discontinuitiesChemical Geology, Vol. 82, No. 1/2, March 30, pp. 21-50South AfricaGeochemistry, Tectonics
DS1991-0676
1991
Andreoli, M.A.G.Hart, R.J., Andreoli, M.A.G., Reimold, W.U., Tredoux, M.Aspects of the dynamic and thermal metamorphic history of the Vredefort cryptoexplosion structure -implications for its originTectonophysics, Vol. 192, No. 3-4, June 20, pp. 313-358South AfricaCryptoexplosion, Geothermometry
DS1995-0201
1995
Andreoli, M.A.G.Brandl, G., McCarthy, T.S., Andreoli, M.A.G., AndersenTectonic and lineament investigations of the Vaalputs area, Namaqualand, South Africa: implications rifting..Centennial Geocongress (1995) Extended abstracts, Vol. 1, p. 445-448. abstractSouth AfricaTectonics
DS1995-0763
1995
Andreoli, M.A.G.Hart, R.J., Hargraves, R.B., Andreoli, M.A.G., TredouxMagnetic anomaly near the center of the Vredefort structure: Implications for impact related signatures.Geology, Vol. 23, No. 3, March pp. 277-280.South AfricaGeophysics -magnetics, Impact Vredefort
DS1995-0764
1995
Andreoli, M.A.G.Hart, R.J., Hargraves, R.B., Andreoli, M.A.G., Tredoux, M.Magnetic anomaly near center Vredefort structure: implications for impact related magnetic signaturesGeology, Vol. 23, No. 3, March pp. 277-280South AfricaPaleomagnetics - remanent, Impact - Vredefort
DS200612-0026
2006
Andreoli, M.A.G.Andreoli, M.A.G., Hart, R.J., Ashwal, L.D., Coetzee, H.Correlations between U, Th content and metamorphic grade in the Western Namaqualand Belt, South Africa: with implications for radioactive heating of the crust.Journal of Petrology, Vol. 47, 6, pp. 1095-1118.Africa, South AfricaGeothermometry
DS201312-0513
2013
Andreoli, M.A.G.Kramers, J.D., Andreoli, M.A.G., Atanasova, M., Belyanin, G.A., Block, D.L., Franklyn, C., Harris, C., Lekgoathi, M., Montross, C.S., Ntsoane, T., Pischedda, V., Segonyane, P., Viljoen, K.S., Westraadt, J.E.Unique chemistry of a diamond bearing pebble from the Libyan desert glass strewnfield, SW Egypt: evidence for a shocked comet fragment.Earth and Planetary Science Letters, Vol.382, pp. 21-31.Africa, EgyptShock diamonds
DS201412-0675
2014
Andreozzi, G.B.Perlinelli, C., Bosi, F., Andreozzi, G.B., Conte, A.M., Armienti, P.Geothermometric study of Cr-spinels of peridotite mantle xenoliths from northern Victoria Land ( Antarctica).American Mineralogist, Vol. 99, pp. 839-846.AntarcticaSpinel
DS201910-2288
2019
Andreozzi, G.B.Nestola, F., Zaffiro, G., Mazzucchelli, M.L., Nimis, P., Andreozzi, G.B., Periotto, B., Princivalle, F., Lenaz, D., Secco, L., Pasqualetto, L., Logvinova, A.M., Sobolev, N.V., Lorenzetti, A., Harris, J.W.Diamond inclusion system recording old deep lithosphere conditions at Udachnaya ( Siberia).Nature Research, Vol. 9, 12586 8p. PdfRussia, Siberiadeposit - Udachnaya

Abstract: Diamonds and their inclusions are unique fragments of deep Earth, which provide rare samples from inaccessible portions of our planet. Inclusion-free diamonds cannot provide information on depth of formation, which could be crucial to understand how the carbon cycle operated in the past. Inclusions in diamonds, which remain uncorrupted over geological times, may instead provide direct records of deep Earth’s evolution. Here, we applied elastic geothermobarometry to a diamond-magnesiochromite (mchr) host-inclusion pair from the Udachnaya kimberlite (Siberia, Russia), one of the most important sources of natural diamonds. By combining X-ray diffraction and Fourier-transform infrared spectroscopy data with a new elastic model, we obtained entrapment conditions, Ptrap?=?6.5(2) GPa and Ttrap?=?1125(32)-1140(33) °C, for the mchr inclusion. These conditions fall on a ca. 35?mW/m2 geotherm and are colder than the great majority of mantle xenoliths from similar depth in the same kimberlite. Our results indicate that cold cratonic conditions persisted for billions of years to at least 200?km in the local lithosphere. The composition of the mchr also indicates that at this depth the lithosphere was, at least locally, ultra-depleted at the time of diamond formation, as opposed to the melt-metasomatized, enriched composition of most xenoliths.
DS202012-2234
2020
Andreozzi, G.B.Mikhailenko, D.S., Stagno, V., Korsakov, A.V., Andreozzi, G.B., Marras, G., Cerantola, V., Malygina, E.V.Redox state determination of eclogite xenoliths from Udachnaya kimberlite pipe ( Siberian craton), with some implications for the graphite/diamond formation.Contributions to Mineralogy and Petrology, Vol. 175, 107, 17p. PdfRussiadeposit - Udachnaya

Abstract: The formation of diamonds within eclogitic rocks has been widely linked to the fate of carbon during subduction and, therefore, referred to conditions of pressure, temperature, and oxygen fugacity (fo2). Mantle-derived eclogite xenoliths from Udachnaya kimberlite pipes represent a unique window to investigate the formation of carbon-free, graphite-diamond-bearing and diamond-bearing rocks from the Siberian craton. With this aim, we exploited oxy-thermobarometers to retrieve information on the P-T-fo2 at which mantle eclogites from the Siberian craton equilibrated along with elemental carbon. The chemical analyses of coupled garnet and omphacitic clinopyroxene were integrated with data on their iron oxidation state, determined both by conventional and synchrotron 57Fe Mössbauer spectroscopy. The calculated fo2s largely vary for each suite of eclogite samples from 0.10 to ? 2.43 log units (?FMQ) for C-free eclogites, from ? 0.01 to ? 2.91 (?FMQ) for graphite-diamond-bearing eclogites, and from ? 2.08 to ? 3.58 log units (?FMQ) for diamond-bearing eclogites. All eclogite samples mostly fall in the fo2 range typical of diamond coexisting with CO2-rich water-bearing melts and gaseous fluids, with diamondiferous eclogites being more reduced at fo2 conditions where circulating fluids can include some methane. When uncertainties on the calculated fo2 are taken into account, all samples essentially fall within the stability field of diamonds coexisting with CO2-bearing melts. Therefore, our results provide evidence of the potential role of CO2-bearing melts as growth medium on the formation of coexisting diamond and graphite in mantle eclogites during subduction of the oceanic crust.
DS1999-0367
1999
AndresenKlein, A.C., Steltenpohl, M.G., Hames, W.E., AndresenDuctile and brittle extension in the southern LOfoten Archipelago:implications for differences in tectonicsAmerican Journal of Science, Vol. 299, Jan. pp. 69-89.NorwayBaltic basement, structure, Collisional margin
DS1990-0888
1990
Andresen, A.Krogh, E.T., Andresen, A., Bryhni, I., Broks, T.M., KristenesenEclogites and polyphase P-T cycling in the Caledonian uppermost allochthonin Troms, northern NorwayJournal of Metamorphic Geology, Vol. 8, No. 3, May pp. 289-310NorwayEclogites
DS1998-0306
1998
AndrewDavies, R., Griffin, W.L., Pearson, N.J., Andrew, DoyleDiamonds from the Deep: Pipe DO 27, Slave Craton, Canada7th International Kimberlite Conference Abstract, pp. 170-172.Northwest TerritoriesDiamond inclusions, Deposit - Pipe DO-27
DS2001-0414
2001
AndrewGriffin, W.L.Win, Davies, Wathanakul, Andrew, MetcalfeDiamonds from Myanmar and Thailand: characteristics and possible originsEconomic Geology, Vol. 96, No. 1, Jan-Feb. pp. 159-79.GlobalAlluvials, Diamond - morphology, textures, chemistry
DS2002-0188
2002
AndrewBonev, I.K., Kerestedjiian, T., Atanassova. R., AndrewMorphogenesis and composition of native gold in the Chelopech volcanic hosted au Cu epithermal deposit.Mineralium Deposita, Vol.BulgariaCopper, gold, Srednogorie zone, Deposit - Chelcopech
DS1998-1625
1998
Andrew, A.Zhang, A., Griffin, W.L., Ryan, C.G., Andrew, A.Conditions of diamond formation beneath the Sino-Korean Craton:paragenesis, temperatures and isotopic cond.7th International Kimberlite Conference Abstract, pp. 992-4.China, LiaoningMineral inclusions, Deposit - Pipe # 50, Shengli #1, Hongqi # 6
DS1998-0584
1998
Andrew, A.J.Harper, G., Andrew, A.J., Fenoulhet, B.Worldwide exploration trends- where is the next exploration romance?Engineering and Mining Journal, Vol. 199, No. 7, July pp. 40-45GlobalEconomics, success, discoveries, Reserves, expenditures
DS1999-0828
1999
Andrew, A.S.Zhang, A., Griffin, W.L., Ryan, C.G., Andrew, A.S.Conditions of diamond formation beneath Liaoning and Shandong Provinces: parageneses, temperatures... carbon7th International Kimberlite Conference Nixon, Vol. 2, pp. 940-47.China, Shandong, LiaoningGeochronology, diamond inclusions, major element analys, Deposit - Mengyin
DS2003-0314
2003
Andrew, A.S.Davies, R.M., Griffin, W.L., O'Reilly, S.Y., Andrew, A.S.Unusual mineral inclusions and carbon isotopes of alluvial diamonds from BingaraLithos, Vol. 69, 1-2, pp. 51-66.AustraliaDeposit - Bingara
DS2003-0315
2003
Andrew, A.S.Davies, R.M., Griffin, W.L., O'Reilly, S.Y., Andrew, A.S.Unusual mineral inclusions and carbon isotopes of alluvial diamonds from BingaraLithos, Vol. 69, 1-2, July, pp. 1-67.Australia, eastern AustraliaDiamond inclusions, geochronology, Deposit - Bingara
DS200412-0414
2003
Andrew, A.S.Davies, R.M., Griffin, W.L., O'Reilly, S.Y., Andrew, A.S.Unusual mineral inclusions and carbon isotopes of alluvial diamonds from Bingara, eastern Australia.Lithos, Vol. 69, 1-2, pp. 51-66.AustraliaDiamond inclusions, Bingara
DS1993-0032
1993
Andrew, C.J.Andrew, C.J.Evaluating mining properties in Eastern Europe: hopeless cases and world-class opportunitiesMining Industry International, No. 1010, January pp. 16-17EuropeEconomics, Ore reserves
DS1860-0531
1887
Andrew, J.Andrew, J.Diamond Digging in South Africa. #1Papers and Proceedings of the Royal Society of Tasmania, PP. 98-106.Africa, South Africa, Griqualand West, Kimberley AreaDiamond Occurrence
DS1994-0052
1994
Andrew, R.L.Andrew, R.L.Australian companies - the new multinationalsAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 5, Sept. pp. 48-52AustraliaEconomics, Company -multinationals
DS1986-0153
1986
Andrews, A.J.Corfu, F., Andrews, A.J.A uranium-lead (U-Pb) age for mineralized Nipissing diabase, GowgAnd a OntarioCanadian Journal of Earth Sciences, Vol. 23, pp. 107-9.OntarioGeochronology
DS1993-0033
1993
Andrews, A.J.Andrews, A.J.The Canadian mineral industry: some key issues and trendsProspectors and Developers Association Exploration and Development, Vol. 5, pp. 9-13CanadaEconomics, Mineral industry -concerns
DS201112-0022
2011
Andrews, A.L.Andrews, A.L., Wang, Z.R., Bolton, E.W., Eckert, J.O.Jr.The effect of diffusion on P-T conditions inferred by cation-exchange thermobarometry.Goldschmidt Conference 2011, abstract p.441.Africa, South AfricaKappvaal Craton, Kimberley
DS202012-2221
2021
Andrews, B.Jackson, C.R.M., Cottrell, E., Andrews, B.Warm and oxidizing slabs limit ingassing efficiency of nitrogen to the mantle.Earth and Planetary Letters, Vol. 553, 116515, 12p. PdfMantlenitrogen

Abstract: Nitrogen is a major and essential component of Earth's atmosphere, yet relative to other volatile elements, there are relatively few experimental constraints on the pathways by which nitrogen cycles between Earth's interior and exterior. We report mineral-melt and mineral-fluid partitioning experiments to constrain the behavior of nitrogen during slab dehydration and sediment melting processes. Experiments reacted rhyolitic melts with silicate and oxide minerals, in the presence of excess aqueous fluid, over temperatures between 725-925 °C and pressures between 0.2 and 2.3 GPa. Oxygen fugacity ranged between iron metal saturation (?NNO-5) to that in excess of primitive arc basalts (?NNO+2). Our experiments demonstrate that hydrous fluid is the preferred phase for nitrogen over minerals (biotite, K-feldspar, and amphibole) and rhyolitic melts across all conditions explored. Relatively large effects of pressure (?log()/?(GPa/K) = 761 ± 68 (1?), ?log()/?(GPa/K) = 462 ± 169) and moderate effects of oxygen fugacity (NNO = -0.20 ± 0.04, ?logNNO = -0.10 ± 0.04) modulate partitioning of nitrogen. We further document negligible partitioning effects related to mineral composition or Cl content of hydrous fluid. Of the minerals investigated, biotite has the largest affinity for N and should control the retention of N in slabs where present. Application of partitioning data to slab dehydration PT paths highlights the potential for highly incompatible behavior ( < 0.1) from the slab along warmer and oxidized (NNO+1) subduction geotherms, whereas dehydration along reduced and cooler geotherms will extract moderate amounts of nitrogen ( > 0.1). We find that slab melting is less effective at extracting N from slabs than fluid loss, at least under oxidized conditions (NNO+1). Ultimately, the conditions under which slabs lose fluid strongly affect the distribution of nitrogen between Earth's interior and exterior.
DS1996-0032
1996
Andrews, C.Andrews, C.UgAnd a and Kenya: waiting in the wingsProspectors and Developers Association of Canada (PDAC) Annual Meeting, p. 67-68. abstract.Uganda, KenyaOverview, Political, legal, resources
DS1994-0053
1994
Andrews, C.B.Andrews, C.B.Role of the world bank in African minerals industryCanadian Institute 1994 Canadian Mining Symposium, Preprint, 22pAfricaEconomics, Mining industry -financing world bank
DS1998-0032
1998
Andrews, C.B.Andrews, C.B.Emerging trends in mining industry partnershipsNatural Resources forum, Vol. 22, No. 2, May 1, pp. 119-126GlobalEconomics, legal, discoveries, success
DS1982-0016
1982
Andrews, D.L.Andrews, D.L.El 761- Ruby Hill, South Australia. Progress and Final Reports from 24/3/81 to 2/6/82.South Australia Open File., No. E4138, 53P.Australia, South AustraliaGeochemistry, Stream Sediment Sampling, Diamonds, Heavy Mineral
DS1995-2047
1995
Andrews, D.L.Wen, Lianxiong, Andrews, D.L.Mantle convection constrained by subduction, geoid, topography andseismology.Eos, Vol. 76, No. 46, Nov. 7. p.F633. Abstract.MantleGeophysics -seismics, Subduction
DS1920-0357
1928
Andrews, E.C.Andrews, E.C.Diamond, 1928New South Wales Geological Survey Report For 1927, PP. 298-300.Australia, New South WalesBlank
DS1960-0622
1966
Andrews, E.M.Andrews, E.M.Georgia's Fabulous Treasure Hoards. a Compendium for Rockhounds.Georgia: Hopeville., 106P. ( DIAMONDS PP. 53-55.).GlobalKimberlite, Diamond, Kimberley
DS201212-0087
2012
Andrews, G.Brett, R.C., Russell, J.K., Andrews, G.Kimberlite ascent: chronicles of olivine.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractMantleDiamond genesis
DS201412-0759
2014
Andrews, G.Russell, K., Brett, C., Jones, T., Andrews, G., Porritt, L.Kimberlite ascent.Goldschmidt Conference 2014, 1p. AbstractMantleKimberlite genesis
DS200812-0768
2008
Andrews, G.D.M.Moss, S., Russell, J.K., Andrews, G.D.M.Progressive infilling of a kimberlite pipe at Diavik, Northwest Territories, Canada: insights from volcanic facies architecture, textures and granulometry.Journal of Volcanology and Geothermal Research, Vol. 174, 1-3, pp. 103-116.Canada, Northwest TerritoriesPhysical volcanology, pyroclastic, crater lakes
DS201012-0517
2009
Andrews, G.D.M.Moss, S., Russell, J.K., Brett, R.C., Andrews, G.D.M.Spatial and temporal evolution of kimberlite magma at A154N, Diavik, Northwest Territories, Canada.Lithos, Vol. 112 S pp. 541-552.Canada, Northwest TerritoriesEmplacement model
DS201907-1523
2019
Andrews, G.D.M.Andrews, G.D.M., Russell, J.K., Cole, B.G.., Brown, S.R.The kimberlite factory: the volcanic nature of kimberlites.Joint 53rd Annual South-Central/53rd North Central/71st Rocky Mtn GSA section Meeting, 1p. AbstractMantlediamond genesis

Abstract: Although traditionally considered the realm of igneous petrologists and geochemists, kimberlites have received attention from physical volcanologists interested in how they are emplaced in the crust and how they can erupt. This presentation will review the evidence for the volcaniclastic (i.e. fragmental) nature of kimberlites from examples in Canada's Northwest Territories and in Pennsylvania. A growing body of evidence indicates that kimberlite magmas are gas-dominated (overwhelmingly CO2) suspensions of molten kimberlite liquid and crystals, usually olivines. The olivines, like other mineral phases and xenoliths, are entrained from the surrounding mantle peridotite wall-rock, rather than crystallized from the meager kimberlite liquid, and are, therefore, overwhelmingly xenocrystic. This crystal and rock fragment load is sampled and mechanically processed by a turbulent gas-jet before being immersed in a bath of kimberlite liquid: this is the kimberlite factory. As the gas-charged crack-tip propagates and ascends, new mantle is processed into the kimberlite factory. Each emplacement event records the passage of a kimberlite factory through the mantle and lithosphere. The Masontown kimberlite in Pennsylvania is a solitary hypabyssal kimberlite dyke but it preserves evidence of the passage of a single kimberlite factory. Although many kimberlites stall in the crust, many erupt explosively to produce indisputably volcaniclastic kimberlite lithofacies associated with diatremes. Open-pit mining of several diatremes in Canada reveals the complex temporal-spatial nature of different emplacement events within the same volcanic field, and the ubiquitous presence of hypabyssal kimberlite dykes that fed or attempted to feed explosive eruptions. Such explosive eruptions sustained tephra plumes that produced kimberlite fall deposits and pyroclastic density currents that produced kimberlite ignimbrites; both of which exited their source diatremes and inundated the surrounding landscape.
DS201907-1535
2019
Andrews, G.D.M.Cole, B.G., Andrews, G.D.M., Brown, S.R., Prellwitz, H.The Masontown kimberlite, Fayette County, Pennsylvania: insights into emplacement processes by the characterization of xenocryst sizes and shapes using computed tomography.Joint 53rd Annual South-Central/53rd North Central/71st Rocky Mtn GSA section Meeting, Vol. 331 United States, Pennsylvaniadeposit - Masontown

Abstract: The late Jurassic Masontown dyke in Fayette County, SW Pennsylvania, preserves abundant rounded, mm to cm-diameter masses of olivine and serpentine cemented together in serpentine-rich kimberlite groundmass. Each mass is interpreted to be a partially serpentinized olivine xenocryst or peridotite xenocryst. Each rounded clast is jacketed by a distinct rim of serpentine; probably originally olivine. The (1) ubiquitous roundness of clasts and (2) the presence of distinct serpentine jackets around each clast, supports emplacement of the dyke by a 'kimberlite factory' (Brett et al., 2015). Due to the paucity of available samples, we have used non-destructive imaging by computed tomography (CT) at the National Energy Technology Lab in Morgantown, WV, to construct 3D models of the internal structure of hand samples loaned from the Smithsonian Institute's Museum of Natural History. MicroCT (1-3 micron resolution) and industrial CT (~15 microns resolution) serial scans processed in ImageJ and Blob3D allow for 3D characterizations of individual clasts, including their shape factors (sphericity, roughness, etc.) and sizes (i.e. crystal size distributions).
DS201909-2015
2019
Andrews, G.D.M.Andrews, G.D.M.The kimberlite factory: the volcanic nature of kimberlites.53rd Annual South-Central 71st Rocky Mtn GSA section meeting, 1p. AbstractMantlediamond genesis

Abstract: Although traditionally considered the realm of igneous petrologists and geochemists, kimberlites have received attention from physical volcanologists interested in how they are emplaced in the crust and how they can erupt. This presentation will review the evidence for the volcaniclastic (i.e. fragmental) nature of kimberlites from examples in Canada's Northwest Territories and in Pennsylvania. A growing body of evidence indicates that kimberlite magmas are gas-dominated (overwhelmingly CO2) suspensions of molten kimberlite liquid and crystals, usually olivines. The olivines, like other mineral phases and xenoliths, are entrained from the surrounding mantle peridotite wall-rock, rather than crystallized from the meager kimberlite liquid, and are, therefore, overwhelmingly xenocrystic. This crystal and rock fragment load is sampled and mechanically processed by a turbulent gas-jet before being immersed in a bath of kimberlite liquid: this is the kimberlite factory. As the gas-charged crack-tip propagates and ascends, new mantle is processed into the kimberlite factory. Each emplacement event records the passage of a kimberlite factory through the mantle and lithosphere. The Masontown kimberlite in Pennsylvania is a solitary hypabyssal kimberlite dyke but it preserves evidence of the passage of a single kimberlite factory. Although many kimberlites stall in the crust, many erupt explosively to produce indisputably volcaniclastic kimberlite lithofacies associated with diatremes. Open-pit mining of several diatremes in Canada reveals the complex temporal-spatial nature of different emplacement events within the same volcanic field, and the ubiquitous presence of hypabyssal kimberlite dykes that fed or attempted to feed explosive eruptions. Such explosive eruptions sustained tephra plumes that produced kimberlite fall deposits and pyroclastic density currents that produced kimberlite ignimbrites; both of which exited their source diatremes and inundated the surrounding landscape.
DS200812-0035
2008
Andrews, J.Andrews, J., Deuss, A.Detailed nature of the 660 km region of the mantle from global receiver function data.Journal of Geophysical Research, Vol. 113, B06304MantleDiscontinuity
DS1991-0416
1991
Andrews, J. T.Dyke, A.S., Andrews, J. T., et al.Radiocarbon dates pertinent to defining the last glacial maximum for Laurentide andGeological Survey of Canada (GSC) Open File, No. 4120, 50p. $ 13.OntarioGeomorphology
DS1975-0073
1975
Andrews, J.R.Emeleus, C.H., Andrews, J.R.Mineralogy and Petrology of Kimberlite Dyke and Sheet Inuclusions and Included Peridoite Xenoliths from Southwest Greenland.Physics and Chemistry of the Earth, Vol. 9, PP. 179-197.GreenlandBlank
DS1982-0494
1982
Andrews, M.C.Peters, D., Mooney, W.D., Andrews, M.C., Ginzburg, A.The Deep Crustal Structure of the Northern Mississippi Embayment.Eos, Vol. 63, No. 45, P. 1118. (abstract.).GlobalMid-continent
DS1983-0464
1983
Andrews, M.C.Mooney, W.D., Andrews, M.C., et al.Crustal Structure of the Northern Mississippi Embayment And a Comparison with Other Continental Rift Zones.Tectonophysics, Vol. 94, PP. 327-348.GlobalMid-continent
DS1985-0204
1985
Andrews, M.J.Fuge, R., Andrews, M.J.The Automated Photometric Determination of Total Fluorine In Mineral Exploration.Journal of Geochemical Exploration., Vol. 23, PP. 293-297.GlobalKimberlite Prospecting
DS1997-0330
1997
Andrews, P.Fallon, G.N., Andrews, P., Bartrop, S.B.Drillhole electromagnetic surveying in the mine environmentExploration Geophysics, Bulletin of Australian, Vol. 27, No. 2-3, Sept. pp. 67-76AustraliaGeophysics - electromagnetic, Drillhole, mining
DS1995-0046
1995
Andrews, P.R.A.Andrews, P.R.A.The beneficiation of Canadian garnet ores at CANMETThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 88, No. 995, Nov/Dec. pp. 55-59CanadaMineral Processing, Garnet
DS201902-0256
2018
Andrews, R.G.Andrews, R.G.Earth is missing a huge part of its crust. Now we may know why. A fifth of the Earth's geologic history might have vanished because planet-wide glaciers buried the evidence.National Geographic, Dec. 31, United States, Arizonageomorphology

Abstract: The Grand Canyon is a gigantic geological library, with rocky layers that tell much of the story of Earth’s history. Curiously though, a sizeable layer representing anywhere from 250 million years to 1.2 billion years is missing. Known as the Great Unconformity, this massive temporal gap can be found not just in this famous crevasse, but in places all over the world. In one layer, you have the Cambrian period, which started roughly 540 million years ago and left behind sedimentary rocks packed with the fossils of complex, multicellular life. Directly below, you have fossil-free crystalline basement rock, which formed about a billion or more years ago. So where did all the rock that belongs in between these time periods go? Using multiple lines of evidence, an international team of geoscientists reckons that the thief was Snowball Earth, a hypothesized time when much, if not all, of the planet was covered in ice.
DS1986-0023
1986
Andrews, R.L.Andrews, R.L., Richards, M.N., Jaques, A.L., Knutson, J., TownendThe Cummins Range carbonatite, Western AustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 12-14AustraliaCarbonatite
DS2002-0206
2002
Andrews, S.J.Broadbent, G.C., Andrews, S.J., Kelso, I.J.A decade of new ideas: geology and exploration history of the Century Zn Pb Ag deposit northeastern QueenslandSociety of Economic Geologists Special Publication, No.9,pp.119-40.Australia, QueenslandZinc, lead, silver. stratabound, Deposit - Century
DS1960-0623
1966
Andrews-Jones, D.A.Andrews-Jones, D.A.Geology and Mineral Resources of the Northern Kambai Hills Schist Belt and Adjacent Granulites.Geological Survey SIERRA LEONE Bulletin., No. 6, 100P.Sierra Leone, West AfricaGeology, Kimberlite
DS1960-0904
1968
Andrews-Jones, D.A.Andrews-Jones, D.A.Petrogenesis and Geochemistry of the Rocks of the Kenema District, Sierra Leone.Leeds: Ph.d. Thesis, University Leeds, Sierra Leone, West AfricaGeochemistry, Genesis, Kimberlite, Mineralogy, Petrology
DS1998-0033
1998
Andrews-Speed, P.Andrews-Speed, P.Fiscal systems for mining - the case of BrasilJournal of Mineral Policy, Vol. 13, No. 2, pp. 13-21BrazilEconomics, Mining - exports, resources, discoveries, success
DS1991-1369
1991
Andreyeva, Y.D.Porovskiy, B.G., Andreyeva, Y.D.Petrography and isotope geochemistry of melilite rocks associated with the Patyn pluton #2International Geology Review, Vol. 33, No. 9, Sept. pp. 689-703RussiaMelilite, Patyn pluton, Petrography, geochemistry
DS1991-1361
1991
Andreyeva, Ye.D.Pokrovskiy, B.G., Andreyeva, Ye.D.Petrography and isotope geochemistry of melilite rocks associated with the Patyn pluton #1International Geology Review, Vol. 33, No. 7, July, pp. 689-703RussiaMelilite, Patyn pluton
DS201412-0724
2013
Andriamampihantona, J.Rasoamalala, V., Salvi, S., Bexiat, D., Ursule, J-Ph., Cuney, M., De Parseval, Ph., Guillaume, D., Moine, B., Andriamampihantona, J.Geology of bastnaesite and monazite deposits in the Ambatofinandrahana area, central part of Madagascar: an overview.Journal of African Earth Sciences, Vol. 94, 14p.Africa, MadagascarBastanesite
DS201607-1326
2016
Andriampenomanana, F.Andriampenomanana, F.Crust and uppermost mantle structure of Madagascar.IGC 35th., Session The Deep Earth 1 p. abstractAfrica, MadagascarGeophysics - seismics
DS201801-0050
2017
Andriampenomanana, F.Pratt, M.J., Wysession, M.E., Aleqabi, G., Wiens, D.A., Nyblade, A., Shore, P., Rambolamanana, G., Andriampenomanana, F., Rakotondraibe, T., Tucker, R.D., Barruol, G., Rindraharisaona, E.Shear velocity structure of the crust and upper mantle of Madagascar derived from surface wave tomography.Earth and Planetary Science Letters, Vol. 458, 1, pp.405-417.Africa, Madagascargeophysics - seismics

Abstract: The crust and upper mantle of the Madagascar continental fragment remained largely unexplored until a series of recent broadband seismic experiments. An island-wide deployment of broadband seismic instruments has allowed the first study of phase velocity variations, derived from surface waves, across the entire island. Late Cenozoic alkaline intraplate volcanism has occurred in three separate regions of Madagascar (north, central and southwest), with the north and central volcanism active until <1 Ma, but the sources of which remains uncertain. Combined analysis of three complementary surface wave methods (ambient noise, Rayleigh wave cross-correlations, and two-plane-wave) illuminate the upper mantle down to depths of 150 km. The phase-velocity measurements from the three methods for periods of 8-182 s are combined at each node and interpolated to generate the first 3-D shear-velocity model for sub-Madagascar velocity structure. Shallow (upper 10 km) low-shear-velocity regions correlate well with sedimentary basins along the west coast. Upper mantle low-shear-velocity zones that extend to at least 150 km deep underlie the north and central regions of recent alkali magmatism. These anomalies appear distinct at depths <100 km, suggesting that any connection between the zones lies at depths greater than the resolution of surface-wave tomography. An additional low-shear velocity anomaly is also identified at depths 50-150 km beneath the southwest region of intraplate volcanism. We interpret these three low-velocity regions as upwelling asthenosphere beneath the island, producing high-elevation topography and relatively low-volume magmatism.
DS200812-0863
2008
Andrianova, E.A.A.A.Patyk-Kara, N.A.G.A., Andrianova, E.A.A.A., Dubinchuk, V.A.T.A.Secondary alterations of zircons in placers.Doklady Earth Sciences, Vol. 419, 1, pp. 253-256.RussiaAlluvials, not specific to diamonds
DS200812-0864
2008
Andrianova, E.A.A.A.Patyk-Kara, N.A.G.A., Andrianova, E.A.A.A., Dubinchuk, V.A.T.A.Secondary alterations of zircons in placers.Doklady Earth Sciences, Vol. 419, 2, pp. 253-256.RussiaAlluvials, zircon, Not specific to diamonds
DS1998-1132
1998
AndriashekPawlowicz, J.G., Eccles, D.R., Fenton, Andriashek, ChowOverview of the Kakwa/Wapiti Study (Map Sheet 83L): implications for diamond exploration.Calgary Mining Forum, Apr. 8-9, p. 43. abstractAlbertaGeology - sampling
DS1996-0033
1996
Andrie, R.Andrie, R.Complexity and scale in geomorphology: statistical self simularity vs characteristic scalesMathematical Geology, Vol. 28, No. 3, pp. 275-293South Africa, Greenland, PhilippinesCoastline, Geomorphology
DS1996-0034
1996
Andrie, R.Andrie, R.Complexity and scale in geomorphology: statistical self-familiarity vs characteristic scales.Mathematical Geology, Vol. 28, No. 3, pp. 275-293.South Africa, Greenland, PhilippinesGeomorphology, Coastline
DS200912-0465
2009
Andriechev, V.L.Makeev, A.B., Andriechev, V.L., Bryanchaninova, N.I.Age of lamprophyres of the Middle Timan: first Rb-Sr data.Doklady Earth Sciences, Vol. 427, 4, pp. 584-587.RussiaLamprophyre
DS1995-1952
1995
AndriessenVan der Beek, P., Andriessen, ClotinghMorphotectonic evolution of rifted continental margins: inferences from acoupled tectonic surface processes model and fission track thermochronology.Tectonics, Vol. 14, No. 2, Apr. pp. 406-21.MantleTectonics - rifting
DS1995-1953
1995
Andriessen, P.Van der Beek, P., Andriessen, P., Cloetingh, S.Morphotectonic evolution of fluid continental margins: inferences from acoupled tectonic surface processes...Tectonics, Vol. 14, No. 2, Apr. pp. 406-21.GlobalTectonics - model, Thermochronology
DS200412-1388
2004
Andriessen, P.A.Murrell, G.R., Andriessen, P.A.Unravelling a long term multi event thermal record in the cratonic interior of southern FIn land through apatite fission track thPhysics and Chemistry of the Earth Parts A,B,C, Vol. 29, 10, pp. 695-706.Europe, FinlandGeobarometry
DS201804-0694
2017
Andriessen, P.A.M.Gouiza, M., Bertotti, G., Andriessen, P.A.M.Mesozoic and Cenozoic thermal history of the Western Reguibat Shield ( West African Craton).Terra Nova, pp. 135-145.Africa, Moroccogeothermometry

Abstract: Using low?temperature thermochronology on apatite and zircon crystals, we show that the western Reguibat Shield, located in the northern part of the West African Craton, experienced significant cooling and heating events between Jurassic and present times. The obtained apatite fission track ages range between 49 and 102 Ma with mean track lengths varying between 11.6 and 13.3 ?m and Dpar values between 1.69 and 3.08 ?m. Zircon fission track analysis yielded two ages of 159 and 118 Ma. Apatite (U-Th)/He uncorrected single?grain ages range between 76 and 95 Ma. Thermal inverse modelling indicates that the Reguibat Shield was exhumed during the Early Cretaceous, Late Cretaceous, Palaeocene-Eocene and Quaternary. These exhumation events were coeval with regional tectonic and geodynamic events, and were probably driven by a combined effect of plate tectonics and mantle dynamics.
DS1910-0316
1913
Andrimont, R.D.Andrimont, R.D.Note sur une Visite Aux Pipes Diamantiferes des Monts Kundelungu (katanga).Soc. Geol. Belge Annual, Vol. 40, PP. 8-19.Democratic Republic of Congo, Central AfricaGeology
DS1910-0482
1916
Andriomont, R.D.Andriomont, R.D.Katanga et Ses Richesses MineralesLa Nature., Dec. 16TH. PP. 385-391.Democratic Republic of Congo, Central AfricaDiamonds, Resources
DS2002-0413
2002
Andritzkym G.Eberle, D.G., Andritzkym G., Hutchins, D.G., Wackerle, R.The regional magnetic data set of Namibia: compilation, contributions to crustal studies and support to natural resource management.South African Journal of Geology, Vol. 105, No. 4, pp. 361-80.NamibiaGeophysics - magnetics, Structure
DS2003-0689
2003
Andronicos, C.Kappus, E., Anthony, E.Y., Andronicos, C.Characterization of the continental mantle in an active rift zone, Kilbourne Hole, New8 Ikc Www.venuewest.com/8ikc/program.htm, Session 9, POSTER abstractNew MexicoBlank
DS200412-0953
2003
Andronicos, C.Kappus, E., Anthony, E.Y., Andronicos, C.Characterization of the continental mantle in an active rift zone, Kilbourne Hole, New Mexico.8 IKC Program, Session 9, POSTER abstractUnited States, New MexicoCraton studies
DS200512-0503
2005
Andronicos, C.Keller, G.R., Karlstrom, K.E., Williams, M.L., Miller, K.C., Andronicos, C., Levander, A.R., Snelson, ProdehlThe dynamic nature of the continental crust-mantle boundary: crustal evolution in the southern Rocky Mountain region as an example.American Geophysical Union, Geophysical Monograph, No. 154, pp. 403-420.United States,Wyoming, Colorado PlateauTectonics
DS201712-2679
2018
Andronicos, C.L.Chen, C., Hersh, G., Fischer, K.M., Andronicos, C.L., Pavlis, G.L., Hamburger, M.W., Marshak, S., Larson, T., Yang, X.Lithospheric discontinuities beneath the U.S. Midcontinent - signatures of Proterozoic terrane accretion and failed rifting.Earth and Planetary Science Letters, Vol. 481, pp. 223-235.United States, Illinois, Indiana, Kentuckygeophysics - seismics Reelfoot Rift

Abstract: Seismic discontinuities between the Moho and the inferred lithosphere-asthenosphere boundary (LAB) are known as mid-lithospheric discontinuities (MLDs) and have been ascribed to a variety of phenomena that are critical to understanding lithospheric growth and evolution. In this study, we used S-to-P converted waves recorded by the USArray Transportable Array and the OIINK (Ozarks-Illinois-Indiana-Kentucky) Flexible Array to investigate lithospheric structure beneath the central U.S. This region, a portion of North America's cratonic platform, provides an opportunity to explore how terrane accretion, cratonization, and subsequent rifting may have influenced lithospheric structure. The 3D common conversion point (CCP) volume produced by stacking back-projected Sp receiver functions reveals a general absence of negative converted phases at the depths of the LAB across much of the central U.S. This observation suggests a gradual velocity decrease between the lithosphere and asthenosphere. Within the lithosphere, the CCP stacks display negative arrivals at depths between 65 km and 125 km. We interpret these as MLDs resulting from the top of a layer of crystallized melts (sill-like igneous intrusions) or otherwise chemically modified lithosphere that is enriched in water and/or hydrous minerals. Chemical modification in this manner would cause a weak layer in the lithosphere that marks the MLDs. The depth and amplitude of negative MLD phases vary significantly both within and between the physiographic provinces of the midcontinent. Double, or overlapping, MLDs can be seen along Precambrian terrane boundaries and appear to result from stacked or imbricated lithospheric blocks. A prominent negative Sp phase can be clearly identified at 80 km depth within the Reelfoot Rift. This arrival aligns with the top of a zone of low shear-wave velocities, which suggests that it marks an unusually shallow seismic LAB for the midcontinent. This boundary would correspond to the top of a region of mechanically and chemically rejuvenated mantle that was likely emplaced during late Precambrian/early Cambrian rifting. These observations suggest that the lithospheric structure beneath the Reelfoot Rift may be an example of a global phenomenon in which MLDs act as weak zones that facilitate the removal of cratonic lithosphere that lies beneath.
DS1993-0034
1993
Andronikov, A.V.Andronikov, A.V., Egorov, L.S., et al.Mesozoic alkaline ultrabasic magmatism of Jetty PeninsulaInternational Gondwana Symposium, III, Editors Findlay, Vol. 8, pp. 547-557.GlobalMelilitites, picrite, nephelinite, Xenoliths
DS1994-0054
1994
Andronikov, A.V.Andronikov, A.V., et al.Abyssal xenoliths from the lamprophyres of the Vestfold Hills, EastAntarctica.Petrology, Vol. 2, No. 3, pp. 250-257.AntarcticaXenoliths, Lamprophyres
DS1998-0034
1998
Andronikov, A.V.Andronikov, A.V., Foley, S.F., Melzer, S.Mantle xenoliths from the Jetty Peninsula area: samples of thermallyeroding lithosphere Lambert-Amery Rift.7th International Kimberlite Conference Abstract, pp. 20-22.AntarcticaTectonics, Magmatism - lherzolite
DS1998-0437
1998
Andronikov, A.V.Foley, S.F., Glaser, S.M., Andronikov, A.V.Non-cratonic garnet peridotites from rifted continental settings in ( Baikal Rift) and East Antarctica7th International Kimberlite Conference Abstract, pp. 217-219.Russia, Baikal, AntarcticaGarnet peridotites
DS2001-0034
2001
Andronikov, A.V.Andronikov, A.V. , Foley, S.F.Trace element and neodymium Strontium isotopic composition of ultramafic lamprophyres from the East Antarctic..Chemical Geology, Vol. 175, No. 3-4, June 1, pp.291-305.AntarcticaBeaver Lake area, Lamprophyres
DS2002-0470
2002
Andronikov, A.V.Foley, S.F., Andronikov, A.V., Melzer, S.Petrology of ultramafic lamprophyres from the Beaver Lake area: their relation to breakup of Gondwanaland.Mineralogy and Petrology, Vol. 74, 2-4, pp. 361-84.eastern AntarcticaLamprophyres, Tectonics
DS2003-0414
2003
Andronikov, A.V.Foley, S.F., Andronikov, A.V.The genesis of ultramafic lamprophyres8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractLabrador, GreenlandKimberlite petrogenesis
DS200412-0564
2003
Andronikov, A.V.Foley, S.F., Andronikov, A.V.The genesis of ultramafic lamprophyres.8 IKC Program, Session 7, AbstractCanada, Quebec, Labrador, Europe, GreenlandKimberlite petrogenesis
DS200612-0403
2006
Andronikov, A.V.Foley, S.F., Andronikov, A.V., Jacob, D.E., Melzer, S.Evidence from Antarctic mantle peridotite xenoliths for changes in mineralogy, geochemistry and geothermal gradients beneath a developing rift.Geochimica et Cosmochimica Acta, Vol. 70, 12, June pp. 3096-3120.AntarcticaGeothermometry
DS1990-0868
1990
AndrosenkoKolesnik, Yu.N., Stepchenko, S.B., Bukhbinder, G.V., AndrosenkoThe orthopyroxene garnet geobarometer for peridotitesInternational Geology Review, Vol. 32, No. 3, March pp. 228-243RussiaPeridotites, Geobarometry
DS201706-1092
2017
Androsova, N.A.Litvin, Yu.A., Bovkun, A.V., Androsova, N.A., Garanin, V.K.The system ilmenite-carbonatite-carbon in the origin of diamond: correlation between the titanium content and the diamond potential of kimberlite.Doklady Earth Sciences, Vol. 473, 1, pp. 286-290.Mantlecarbonatite

Abstract: Experimental studies of melting relations in the system ilmenite-K-Na-Mg-Fe-Ca carbonatite-carbon at 8 GPa and 1600°C provide evidence for the effect of liquid immiscibility between ilmenite and carbonatite melts. It is shown that the solubility of ilmenite in carbonatitic melts is negligible and does not depend on its concentration in experimental samples within 25-75 wt %. However, carbonatite-carbon melts are characterized by a high diamond-forming efficiency. This means that the correlation between the concentration of TiO2 and diamond content is problematic for mantle chambers and requires further, more complex, experimental studies.
DS2001-0597
2001
AndrutKhisina, N.R., Wirth, R., Langer, K., Andrut, UkhanovMicrostructure of experimentally oxidized olivine from a mantle nodule 1. modes of Fe3 and OH occurrence.Geochemistry International, Vol. 39, No. 4, pp. 327-35.GlobalPetrology - experimental, Nodule
DS2002-0842
2002
Andrut, M.Khisina, N.R., Wirth, R., Andrut, M.Modes of OH occurrence in mantle olivine. 1. structural hydroxylGeochemistry International, Vol.40,2,pp.332-41.GlobalMineralogy - olivine
DS2002-0843
2002
Andrut, M.Khisina, N.R., Wirth, R., Andrut, M.Modes of OH occurrence in mantle olivine 1. structural hydroxylGeochemistry International, Vol.40,4,pp.332-41.GlobalPetrology - olivine
DS1996-0035
1996
Andryeva, I.A.Andryeva, I.A., Naumov, V.B., et al.Magmatic celestite in melt inclusions in apatite from the Mushugay Khuduk alkai volcano plutonic complex.Doklady Academy of Sciences, Vol. 339A, No. 9 Feb., pp. 154-159.GlobalNephelinite, melaleucite, Carbonatite
DS200512-0728
2004
Andryushchenko, Y.N.Mints, M.V., Berzin, R.G., Andryushchenko, Y.N., Zamozhnyaya, N.G., Zlobin, Konilov, Stupak, SuleimanovThe deep structure of the Karelian Craton along Geotraverse 1-EB.Geotectonics, Vol. 38, 5, pp. 329-342.RussiaGeophysics - seismics
DS201802-0218
2018
Anegawa, Y.Akaogi, M., Kawahara, A., Kojitani, H., Yoshida, K., Anegawa, Y., Ishii, T.High pressure phase transitions in MgCr2O4 MgSiO4 composition: reactions between olivine and chromite with implications for ultrahigh pressure chromitites.American Mineralogist, Vol. 103, pp. 161-170.Mantlechromites
DS201505-0243
2015
Anenburg, M.Katzir, Y., Anenburg, M., Kaminchik, J., Segev, A., Blichert-Toft, J., Spicuzza, M.J., Valley, J.W.Garnet pyroxenites as markers of recurring extension and magmatism at the rifted margins of the Levant basin.Israel Geological Society, Abstracts 1p.Europe, Israel, Mt. CarmelPyroxenite
DS202010-1825
2020
Anenburg, M.Anenburg, M., Mavrogenes, J.A., Bennett, V.C.The fluorapatite P-REE-Th vein deposit at Nolans Bore: genesis by carbonatite metasomatism.Journal of Petrology, Vol. 61, 1, egaa003 42p. PdfAustralia, Northern Territorydeposit - Nolans Bore

Abstract: Nolans Bore is a rare earth element (REE) ore deposit in the Reynolds Range, Aileron Province, Northern Territory, Australia. It consists primarily of fluorapatite and alteration products thereof, surrounded by a diopside-dominated selvage. Previously considered to form via hydrothermal fluids, we now suggest that the deposit formed by a metasomatic reaction between a mantle-derived carbonatite and granulite-facies felsic host rocks, after peak metamorphism. REE patterns of fluorapatite are strongly light REE (LREE) enriched, convex with maxima at Ce to Nd, and contain a weak negative Eu anomaly. Textural and geochemical properties of the fluorapatite are consistent with its formation from a carbonatite liquid. Sinusoidal REE patterns in diopside along with strong Yb-Lu enrichment relative to coexisting titanite are suggestive of derivation from a Ca-rich carbonatite. Likewise, hyalophane present in the selvages forms by reaction of a BaCO3 component in the carbonatite with K-feldspar in the silicate host rocks. The overall morphology of Nolans Bore is consistent with carbonatite-silicate reaction experiments, with the carbonatite itself migrating elsewhere owing to the open-system nature of Nolans Bore. Ekanite veins in massive fluorapatite zones and allanite-epidote crusts on fluorapatite in contact with the diopside selvages formed by hydrothermal fluids exsolved from the carbonatite. Minor interstitial calcite was not igneous but was the last mineral to crystallize from the carbonatite-exsolved fluid. Y/Ho ratios qualitatively trace the transition from mantle-dominated igneous minerals to later low-temperature hydrothermal minerals. Rb-Sr and Sm-Nd analyses of unaltered minerals (fluorapatite, allanite, calcite) show that the carbonatite had homogeneous initial 87Sr/86Sr???0•7054 and ?Nd???-4 at 1525?Ma, the best age estimate of the mineralization. Fluorapatite-allanite Sm-Nd dating results in an age of 1446?±?140?Ma, consistent with forming soon after the end of the Chewings Orogeny. Neodymium depleted mantle model ages are older than 2?Ga, indicating the presence of recycled crustal material within the source. We suggest that the carbonatite was sourced from a mantle enriched by subduction of LREE-rich oceanic crustal rocks, marine sediments, and phosphorites, potentially from the south, or the Mount Isa area to the east. Nolans Bore represents the root zone of a now-eroded carbonatite. Other Nolans-type deposits (Hoidas Lake, Canada and Kasipatnam, India) are similarly hosted within siliceous granulite-facies rocks in regions with a long tectonic history, suggesting common processes that led to the formation of all three deposits. The REE-rich compositions of the mid-crustal Nolans Bore fluorapatite are the cumulates hypothesized to cause REE depletion in some unmineralized carbonatites. The rocks at Nolans Bore demonstrate that carbonatites, previously thought to be mostly unreactive, can undergo modification and modify the composition of the silicate rocks which they encounter, forming an ‘antiskarn’. At igneous temperatures, the resulting mineral assemblage (other than fluorapatite) consists of diopside and titanite, both of which are common in granulite-facies rocks. Therefore, carbonatite metasomatism can remain unnoticed if the resulting assemblage does not contain distinctively carbonatitic minerals.
DS202011-2026
2020
Anenburg, M.Anenburg, M.Rare earth mineral diversity controlled by REE pattern shapes.Mineralogical Magazine, doi.10.1180/mgm.2020.70 11p. PdfMantleREE

Abstract: The line connecting rare earth elements (REE) in chondrite-normalised plots can be represented by a smooth polynomial function using ? shape coefficients as described by O'Neill (2016). In this study, computationally generated ? combinations are used to construct artificial chondrite-normalised REE patterns that encompass most REE patterns likely to occur in natural materials. The dominant REE per pattern is identified, which would lead to its inclusion in a hypothetical mineral suffix, had this mineral contained essential REE. Furthermore, negative Ce and Y anomalies, common in natural minerals, are considered in the modelled REE patterns to investigate the effect of their exclusion on the relative abundance of the remainder REE. The dominant REE in a mineral results from distinct pattern shapes requiring specific fractionation processes, thus providing information on its genesis. Minerals dominated by heavy lanthanides are rare or non-existent, even though the present analysis shows that REE patterns dominated by Gd, Dy, Er and Yb are geologically plausible. This discrepancy is caused by the inclusion of Y, which dominates heavy REE budgets, in mineral name suffixes. The focus on Y obscures heavy lanthanide mineral diversity and can lead to various fractionation processes to be overlooked. Samarium dominant minerals are known, even though deemed unlikely by the computational model, suggesting additional fractionation processes that are not well described by ? shape coefficients. Positive Eu anomalies only need to be moderate in minerals depleted in the light REE for Eu to be the dominant REE, thus identifying candidate rocks in which the first Eu dominant mineral might be found. Here, I present an online tool, called ALambdaR that allows interactive control of ? shape coefficients and visualisation of resulting REE patterns.
DS202011-2027
2020
Anenburg, M.Anenburg, M., Mavrogenes, J.A., Frigo, C., Wall, F.Rare earth element mobility in and around carbonatites controlled by sodium, potassium, and silica.Science Advances, Vol. 6, 11p. 10.1126/sciadv.abb6570 pdfGlobalcarbonatites, REE

Abstract: Carbonatites and associated rocks are the main source of rare earth elements (REEs), metals essential to modern technologies. REE mineralization occurs in hydrothermal assemblages within or near carbonatites, suggesting aqueous transport of REE. We conducted experiments from 1200°C and 1.5 GPa to 200°C and 0.2 GPa using light (La) and heavy (Dy) REE, crystallizing fluorapatite intergrown with calcite through dolomite to ankerite. All experiments contained solutions with anions previously thought to mobilize REE (chloride, fluoride, and carbonate), but REEs were extensively soluble only when alkalis were present. Dysprosium was more soluble than lanthanum when alkali complexed. Addition of silica either traps REE in early crystallizing apatite or negates solubility increases by immobilizing alkalis in silicates. Anionic species such as halogens and carbonates are not sufficient for REE mobility. Additional complexing with alkalis is required for substantial REE transport in and around carbonatites as a precursor for economic grade-mineralization.
DS202203-0334
2021
Anenburg, M.Anenburg, M., Broom-Fendley, S., Chen, W.Formation of rare earth deposits in carbonatites. Burbankite, alkaline complexes.Elements, Vol. 17, 327-232.GlobalRare earths, REE

Abstract: Carbonatites and related rocks are the premier source for light rare earth element (LREE) deposits. Here, we outline an ore formation model for LREE-mineralised carbonatites, reconciling field and petrological observations with recent experimental and isotopic advances. The LREEs can strongly partition to carbonatite melts, which are either directly mantle-derived or immiscible from silicate melts. As carbonatite melts evolve, alkalis and LREEs concentrate in the residual melt due to their incompatibility in early crystal-lising minerals. In most carbonatites, additional fractionation of calcite or ferroan dolomite leads to evolution of the residual liquid into a mobile alkaline “brine-melt” from which primary alkali REE carbonates can form. These primary carbonates are rarely preserved owing to dissolution by later fluids, and are replaced in-situ by monazite and alkali-free REE-(fluor)carbonates.-
DS1989-0027
1989
Anfiloff, V.Anfiloff, V.Structural interpretation of the Rukwa Rift, Tanzania.. discussion andreplyGeophysics, Vol. 54, No. 11, November pp. 1499-1500TanzaniaTectonics, Rukwa Rift
DS1987-0174
1987
Anfilogov, V.N.Dymkin, A.M., Bobylev, I.B., Anfilogov, V.N.Study of low temperature immiscibility of melts in the systemleucite-fayalite-anorthite-silicaDoklady Academy of Science USSR, Earth Science Section, Vol. 284, No. 5, Publishing July 1987, pp. 120-122RussiaLeucite
DS2000-0022
2000
Anfilogov, V.N.Anfilogov, V.N., Kabanova, L.Ya., Korablev, A.G.Origin of Diamondiferous tuffisites in the northern UralsDoklady Academy of Sciences, Vol. 371a, No. 3, Mar-Apr. pp. 437-9.Russia, UralsDiamond genesis, Tuffisites
DS2000-0023
2000
Anfilogov, V.N.Anfilogov, V.N., Korablev, A.G., Kabanova, L.Y.Fluid tectonic mobilization of the buried crusts of kimberlite weathering and origin Urals diamond depositsJournal of Geochem. Exp., Vol. 69-70, pp. 327-31.Russia, UralsAlluvials, placers, weathering, kimberlite, Source, genesis of diamonds
DS2001-0035
2001
Anfilogov, V.N.Anfilogov, V.N.Impact origin of ancient diamonds with eclogitic and meteoritic parageneses of mineral inclusions.Doklady Academy of Sciences, Vol. 377, No. 2, Feb-Mar. pp.219-20.RussiaEclogites, Diamonds - mineral inclusions
DS200412-0041
2004
Anfilogov, V.N.Anfilogov, V.N.Conditions of incipience and growth of diamond crystals. *** RUSSIAN LANGUAGEProceedings of the Russian Mineralogical Society ***in RUSSIAN, Vol. 133, 1,pp.110-116. ***RUSSIANTechnologyDiamond morphology
DS200612-0027
2006
Anfilogov, V.N.Anfilogov, V.N., Khachai, Y.V.Hydroextrusion as a possible mechanism for the ascent of diapirs, domes and mantle plumes.Geochemistry International, Vol. 44, 8, pp. 808-813.MantlePlume, water
DS200812-0036
2007
Anfilogov, V.N.Anfilogov, V.N.The harnessing of the ASM diagram for genetic analyses of the magmatic rock series.Vladykin Volume 2007, pp. 183-TechnologyMagmatism
DS201012-0010
2009
Anfilogov, V.N.Anfilogov, V.N.Thermal convection and plumes in the crystalline Earth mantle.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp.13-19.MantleGeothermometry
DS201112-0023
2011
Anfilogov, V.N.Anfilogov, V.N., Khachai, Yu.A.A possible scenario of material differentiation at the initial stage of the Earth's formation.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 126-131.MantleComplexity of dense iron core and silicate mantle
DS201312-0023
2013
Anfilogov, V.N.Anfilogov, V.N., Khachai, Yu.V.Origin of kimberlitic diamond bearing lithosphere of cratons.Doklady Earth Sciences, Vol. 451, 2, pp. 814-817.RussiaDeposit - AK8
DS200812-0037
2008
Anfilov, V.N.Anfilov, V.N., Khachay, Y.V.The mechanism of the Earth core and silicate envelopes formation.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., 2008 pp. 5-13.MantleSilicate
DS1989-0979
1989
Angel, R.McCormick, T.C., Hazen, R.M., Angel, R.Compressability of omphacite to 60 KBAR: role of vacanciesAmerican Mineralogist, Vol. 74, No. 11-12, pp. 1287-1292South AfricaCrystallography, Eclogites
DS1997-0032
1997
Angel, R.Angel, R.Mineralogy: the earth's mantle remodeledNature, Vol. 385, No. 6616, Feb. 6, p. 489.MantleBlank
DS201312-0643
2013
Angel, R.Nestola, F., Nimis, P., Milani, S., Angel, R., Bruno, M., Harris, J.W.Crystallographic relationships between diamond and its olivine inclusions. An update.Goldschmidt 2013, AbstractRussia, YakutiaUdachnaya
DS201705-0807
2017
Angel, R.Alvaro, M., Angel, R., Nimis, P., Milani, S., Harris, J., Nestola, F.Orientation relationship between diamond and magnesiochromite inclusions.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 12200 AbstractRussiaDeposit - Udachnaya

Abstract: The correct determination of the relative crystallographic orientations of single crystals has many applications. When single crystals undergo phase transitions, especially at high pressures, the relative orientations of the two phases yields insights into transition mechanisms (Dobson et al 2013). On the other hand, determination of the crystallographic orientations of minerals included in diamonds can provide insights into the mechanisms of their entrapment and the timing of their formation relative to the host diamond (e.g. Nestola et al. 2014, Milani et al. 2016). The reported occurrence of non-trivial orientations for some minerals in diamonds, suggesting an epitaxial relationship, has long been considered to reflect contemporaneous growth of the diamond and the inclusion (e.g. syngenesis). Correct interpretation of such orientations requires (i) a statistically significant crystallographic data set for single and multiple inclusions in a large number of diamonds, and (ii) a robust data-processing method, capable of removing ambiguities derived from the high symmetry of the diamond and the inclusion. We have developed a software to perform such processing (OrientXplot, Angel et al. 2015), starting from crystallographic orientation matrixes obtained by X-ray diffractometry or EBSD data. Previous studies of inclusions in lithospheric diamonds, by single-crystal X-ray diffraction and EBSD, indicate a wide variety in the orientations of different inclusion phases with respect to their diamond host (Futergendler & Frank-Kamenetsky 1961; Frank-Kamenetsky 1964; Wiggers de Vries et al. 2011; Nestola et al. 2014, Milani et al. 2016). For example, olivine inclusions in lithospheric diamonds from Udachnaya do not show any preferred orientations with respect to their diamond hosts, but multiple inclusions in a single diamond often show very similar orientations within few degrees. In the present work on magnesiochromite inclusions in diamonds from Udachnaya, there is a partial orientation between inclusion and host. A (111) plane of each inclusion is sub-parallel to a {111} plane of their diamond host, but with random orientations of the magnesiochromite [100], [010] and [001] relative to the diamond. In one case, where a single inclusion comprised a magnesiochromite-olivine touching pair, the magnesiochromite was oriented as noted above and the olivine showed a random orientation. The implications of these observations for the mechanisms of diamond growth will be explored and the results will be compared and combined with previous work.
DS1987-0453
1987
Angel, R.J.McCormick, T.C., Hazen, R.M., Angel, R.J.Effect of vacancies on compressibilities of mantle ophacitesGeological Society of America, Vol. 19, No. 7 annual meeting abstracts, p.765. abstracSouth AfricaKimberlite
DS1992-0030
1992
Angel, R.J.Angel, R.J., Chopelas, A., oss, N.L.Stability of high density clinoenstatite at upper-mantle pressuresNature, Vol. 358, No. 6384, July 23, pp. 322-325MantleClinoenstatite, Mineralogy
DS1994-0790
1994
Angel, R.J.Hugh-Jones, D.A., Woodland, A.B., Angel, R.J.The structure of high pressure C2 c ferrosilite and crystal chemistry of high pressure C2 c pyroxenes.American Mineralogist, Vol. 79, pp. 1032-41.MantlePetrology - experimental pyroxenes, ultra high pressure (UHP)
DS1997-0033
1997
Angel, R.J.Angel, R.J., Ross, N.L.Equations of state of mantle minerals from high pressurePhysics and Chem. Earth, Vol. 22, No. 1-2, pp. 119-123.MantleMineralogy, Ultrahigh pressure
DS1999-0122
1999
Angel, R.J.Chakraborty, S., Knoche, R., Angel, R.J.Enhancement of cation diffusion rates across the 410 Km discontinuity inEarth's mantles.Science, Vol. 283, No. 5400, Jan. 15, pp. 362-5.MantleDiscontinuity
DS2001-0036
2001
Angel, R.J.Angel, R.J., Frost, D.J., Ross, N.L., Hemley, R.Stabilities and equations of state of dense hydrous magesium silicatesPhysics of the Earth and Planetary Interiors, Vol. 127, No. 1-4, Dec. 1, pp. 181-96.MantleMineralogy - silicates, Subduction - geodynamics, rheology
DS2003-0019
2003
Angel, R.J.Andrault, D., Angel, R.J., Mosenfelder, J.L., LeBihan, T.Equation of state of stishovite to lower mantle pressuresAmerican Mineralogist, Vol. 88, 2,3pp. 301-7.MantleMineralogy
DS201112-1144
2011
Angel, R.J.Yu, Y.G., Wentzcovitch, R.M., Vinograd, V.L., Angel, R.J.Thermodynamic properties of MgSiO3 majorite and phase transitions near 660 km depth in MgSiO3 and Mg2SiO4: a first principles study.Journal of Geophysical Research, Vol. 116, B02208 ( 19p)MantleThermodynamics
DS201212-0471
2012
Angel, R.J.Milani, S., Nestola, F., Angel, R.J., Pasqual, D., Geoger, C.A.Equation of state of almandine and implications for diamond geobarometry.emc2012 @ uni-frankfurt.de, 1p. AbstractMantleDiamond inclusions
DS201412-0620
2014
Angel, R.J.Nestola,F., Nimis, P.,Angel, R.J., Milani, Bruno, S.,Prencipe, M., Harris, J.W.Olivine with diamond-imposed morphology included in diamonds. Syngenesis or Protogenesis.International Geology Review, Vol. 56, 13, pp. 1658-1667.RussiaDeposit - Udachnaya
DS201502-0038
2015
Angel, R.J.Angel, R.J., Alvaro, M., Nestola, F., Mazzucchelli, M.L.Diamond thermoelastic properties and implications for determining the pressure of formation of diamond inclusion systems.Russian Geology and Geophysics, Vol. 56, 1-2, pp. 211-220.TechnologyDiamond inclusions

Abstract: The formation conditions of diamond can be determined from the residual pressure of inclusions trapped within the diamond, as measured at ambient conditions, and the equations of state (EoS) of the mineral inclusion and the host diamond. The EoS parameters of the diamond and the inclusion phase are therefore critical for determining the precision and accuracy of the calculation of formation conditions of diamonds. The questions we address are (i) How precise are these calculations? and, in particular, (ii) Do we know the EoS parameters of diamond to a precision and accuracy which do not contribute significantly to uncertainties in the geological conclusions drawn from these calculations? We present a review of the most recent compressional data, simulations, and direct elastic measurements of diamond and show them to be consistent with a room-temperature bulk modulus of K0T = 444(2) GPa and a pressure derivative K = 4.0. In combination with a thermal-pressure model with parameters aV300,0 = 2.672(3) x 10- 6 K- 1 and a single Einstein temperature 0E = 1500 K, the volume variation of diamond from room conditions to pressures and temperatures exceeding those in the Earth’s transition zone is described to within the levels of uncertainty inherent in both experimental and computational determinations. For the example of olivine inclusions in diamond, these uncertainties in the diamond EoS parameters lead to uncertainties in the entrapment pressures of no more than 0.001 GPa at low temperatures and 0.008 GPa at higher temperatures.
DS201603-0376
2016
Angel, R.J.Ferrero, S., Ziemann, M.A., Angel, R.J., Obrien, P.J., Wunder, B.Kumdykolite, kokchetavite, and cristobalite crystallized in nanogranites from felsic granulites, Orlica-Snieznik Dome, ( Bohemian Massif): not an evidence for ultrahigh-pressure conditions.Contributions to Mineralogy and Petrology, Vol. 171, pp. 1-12.EuropeBohemian

Abstract: A unique assemblage including kumdykolite and kokchetavite, polymorphs of albite and K-feldspar, respectively, together with cristobalite, micas, and calcite has been identified in high-pressure granulites of the Orlica-Snieznik dome (Bohemian Massif) as the product of partial melt crystallization in preserved nanogranites. Previous reports of both kumdykolite and kokchetavite in natural rocks are mainly from samples that passed through the diamond stability field. However, because the maximum pressure recorded in these host rocks is <3 GPa, our observations indicate that high pressure is not required for the formation of kumdykolite and kokchetavite, and their presence is not therefore an indicator of ultrahigh-pressure conditions. Detailed microstructural and microchemical investigation of these inclusions indicates that such phases should instead be regarded as (1) a direct mineralogical criteria to identify former melt inclusions with preserved original compositions, including H2O and CO2 contents and (2) indicators of rapid cooling of the host rocks. Thus, the present study provides novel criteria for the interpretation of melt inclusions in natural rocks and allows a more rigorous characterization of partial melts during deep subduction to mantle depth as well as their behavior on exhumation.
DS201608-1423
2016
Angel, R.J.Milani, S., Nestola, F., Angel, R.J., Nimis, P., Harris, J.W.Crystallographic orientations of olivine inclusions in diamonds.Lithos, in press available , 5p.Africa, South AfricaDeposit - Cullinan, Koffiefontein, Bultfontein

Abstract: In this work we report for the first time the crystallographic orientations of olivine inclusions trapped in diamonds from the Kaapvaal craton (South Africa) determined by single-crystal X-ray diffraction, and analyze them together with all available data in the literature. The overall data set indicates no preferred orientation of the olivine inclusions with respect to their diamond hosts. However, diamonds containing multiple olivine inclusions sometimes show clusters of olivines with the same orientation in the same diamond host. We conclude that such clusters can only be interpreted as the remnants of single olivine crystals pre-dating the growth of the host diamonds.
DS201608-1428
2016
Angel, R.J.Nimis, P., Alvaro, M., Nestola, F., Angel, R.J., Marquardt, K., Rustioni, G., Harris, J.W., Marone, F.First evidence of hydrous silicic fluid films around solid inclusions in gem-qualty diamonds.Lithos, Vol. 260, pp. 384-389.Russia, Africa, South AfricaDeposit - Udachnaya, Premier

Abstract: Diamonds form from fluids or melts circulating at depth in the Earth's mantle. Analysis of these fluids is possible if they remain entrapped in the diamond during its growth, but this is rarely observed in gem-quality stones. We provide the first evidence that typical mineral inclusions in gem-quality diamonds from the Siberian and Kaapvaal cratons are surrounded by a thin film of hydrous silicic fluid of maximum thickness 1.5 ?m. The fluid contains Si2O(OH)6, Si(OH)4, and molecular H2O and was identified using confocal micro-Raman spectroscopy and synchrotron-based X-ray tomographic microscopy. As the solid mineral inclusions have both peridotitic and eclogitic affinities and occur in two cratonic regions, our results demonstrate the strong connection between water-rich fluids and the growth of gem-quality lithospheric diamonds. The presence of the fluid films should be taken into account for a proper evaluation of H2O contents in the mantle based on H2O contents in solid inclusions and for a robust assessment of diamond formation pressures based on the residual pressures of the inclusions.
DS201611-2095
2016
Angel, R.J.Anzolini, C., Angel, R.J., Merlini, M., Derzsi, M., Tokar, K., Milani, S., Krebs, M.Y., Brenker, F.E., Nestola, F., Harris, J.W.Depth of formation of CaSi)3 - walstromite included in super -deep diamonds.Lithos, in press available 43p.South America, Brazil, Mato GrossoDeposit - Juina

Abstract: "Super-deep" diamonds are thought to crystallize between 300 and 800 km depth because some of the inclusions trapped within them are considered to be the products of retrograde transformation from lower mantle or transition zone precursors. In particular, single inclusion CaSiO3-walstromite is believed to derive from CaSiO3-perovskite, although its real depth of origin has never been proven. Our aim is therefore to determine for the first time the pressure of formation of the diamond-CaSiO3-walstromite pair by “single-inclusion elastic barometry” and to determine whether CaSiO3-walstromite derives from CaSiO3-perovskite or not. We investigated several single phases and assemblages of Ca-silicate inclusions still trapped in a diamond coming from Juina (Brazil) by in-situ analyses (single-crystal X-ray diffraction and micro-Raman spectroscopy) and we obtained a minimum entrapment pressure of ~ 5.7 GPa (? 180 km) at 1500 K. However, the observed coexistence of CaSiO3-walstromite, larnite (?-Ca2SiO4) and CaSi2O5-titanite in one multiphase inclusion within the same diamond indicates that the sample investigated is sub-lithospheric with entrapment pressure between ~ 9.5 and ~ 11.5 GPa at 1500 K, based on experimentally-determined phase equilibria. In addition, thermodynamic calculations suggested that, within a diamond, single inclusions of CaSiO3-walstromite cannot derive from CaSiO3-perovskite, unless the diamond around the inclusion expands by ~ 30% in volume.
DS201709-1952
2017
Angel, R.J.Angel, R.J., Alvaro, M., Nestola, F.40 years of mineral elasticity: a critical review and a new parameterisation of equations of state for mantle olivines and diamond inclusions.Physics and Chemistry of Minerals, in press available, 19p.Technologydiamond inclusions

Abstract: Elasticity is a key property of materials, not only for predicting volumes and densities of minerals at the pressures and temperatures in the interior of the Earth, but also because it is a major factor in the energetics of structural phase transitions, surface energies, and defects within minerals. Over the 40 years of publication of Physics and Chemistry of Minerals, great progress has been made in the accuracy and precision of the measurements of both volumes and elastic tensors of minerals and in the pressures and temperatures at which the measurements are made. As an illustration of the state of the art, all available single-crystal data that constrain the elastic properties and pressure–volume–temperature equation of state (EoS) of mantle-composition olivine are reviewed. Single-crystal elasticity measurements clearly distinguish the Reuss and Voigt bulk moduli of olivine at all conditions. The consistency of volume and bulk modulus data is tested by fitting them simultaneously. Data collected at ambient pressure and data collected at ambient temperature up to 15 GPa are consistent with a Mie–Grünesien–Debye thermal-pressure EoS in combination with a third-order Birch–Murnaghan (BM) compressional EoS, the parameter V0 = 43.89 cm3 mol?1, isothermal Reuss bulk modulus KTR,0=126.3(2) GPaKTR,0=126.3(2) GPa, K?TR,0=4.54(6)KTR,0?=4.54(6), a Debye temperature ?D=644(9)K?D=644(9)K, and a Grüneisen parameter ?0 = 1.044(4), whose volume dependence is described by q = 1.9(2). High-pressure softening of the bulk modulus at room temperature, relative to this EoS, can be fit with a fourth-order BM EoS. However, recent high-P, T Brillouin measurements are incompatible with these EoS and the intrinsic physics implied by it, especially that (?K?TR?T)P>0(?KTR??T)P>0. We introduce a new parameterisation for isothermal-type EoS that scales both the Reuss isothermal bulk modulus and its pressure derivative at temperature by the volume, KTR(T,P=0)=KTR,0[V0V(T)]?TKTR(T,P=0)=KTR,0[V0V(T)]?T and K?TR(T,P=0)=K?TR,0[V(T)V0]??KTR?(T,P=0)=KTR,0?[V(T)V0]??, to ensure thermodynamic correctness at low temperatures. This allows the elastic softening implied by the high-P, T Brillouin data for mantle olivine to be fit simultaneously and consistently with the same bulk moduli and pressure derivatives (at room temperature) as the MGD EoS, and with the additional parameters of ?V0 = 2.666(9) × 10?5 K?1, ?E=484(6)?E=484(6), ?T?T = 5.77(8), and ???? = ?3.5(1.1). The effects of the differences between the two EoS on the calculated density, volume, and elastic properties of olivine at mantle conditions and on the calculation of entrapment conditions of olivine inclusions in diamonds are discussed, and approaches to resolve the current uncertainties are proposed.
DS201712-2672
2017
Angel, R.J.Angel, R.J., Mazzucchelli, M.L., Alvaro, M., Nestola, F.EosFit-Pinc: a simple GUI for host inclusion elastic thermobarometry.American Mineralogist, Vol. 102, pp. 1957-1960.Technologygeobarometry

Abstract: Elastic geothermobarometry is a method of determining metamorphic conditions from the excess pressures exhibited by mineral inclusions trapped inside host minerals. An exact solution to the problem of combining non-linear Equations of State (EoS) with the elastic relaxation problem for elastically isotropic spherical host-inclusion systems without any approximations of linear elasticity is presented. The solution is encoded into a Windows GUI program EosFit-Pinc. The program performs host-inclusion calculations for spherical inclusions in elastically isotropic systems with full P-V-T EoS for both phases, with a wide variety of EoS types. The EoS values of any minerals can be loaded into the program for calculations. EosFit-Pinc calculates the isomeke of possible entrapment conditions from the pressure of an inclusion measured when the host is at any external pressure and temperature (including room conditions), and it can calculate final inclusion pressures from known entrapment conditions. It also calculates isomekes and isochors of the two phases.
DS201712-2673
2016
Angel, R.J.Angel, R.J., Milani, S., Alvaro, M., Nestola, F.High quality structures at high pressure? Insights from inclusions in diamonds.Zeitschrfit fur Kristallographie, Vol. 231, pp. 467-473.Technologydiamond inclusions

Abstract: We describe the experimental protocols necessary to measure the crystal structures of minerals trapped within diamonds by single-crystal X-ray diffraction to the same quality as obtained from minerals studied at ambient conditions. The results show that corrections for X-ray absorption in complex cases can be made with good precision. Comparison of the refined structure of a single-crystal olivine inclusion inside a diamond with the structure of a similar olivine held in a high-pressure diamond-anvil cell shows that data resolution, not the correction for absorption effects, is the dominant factor in influencing the quality of structures determined at high pressures by single-crystal X-ray diffraction.
DS201804-0669
2018
Angel, R.J.Angel, R.J., Alvaro, M., Nestola, F.40 years of mineral elasticity: a critical review and a new parameterisation of equations of state for mantle olivines and diamond inclusions.Physics and Chemistry of Minerals, Vol. 45, 2, pp. 95-131.Mantleolivines

Abstract: Elasticity is a key property of materials, not only for predicting volumes and densities of minerals at the pressures and temperatures in the interior of the Earth, but also because it is a major factor in the energetics of structural phase transitions, surface energies, and defects within minerals. Over the 40 years of publication of Physics and Chemistry of Minerals, great progress has been made in the accuracy and precision of the measurements of both volumes and elastic tensors of minerals and in the pressures and temperatures at which the measurements are made. As an illustration of the state of the art, all available single-crystal data that constrain the elastic properties and pressure–volume–temperature equation of state (EoS) of mantle-composition olivine are reviewed. Single-crystal elasticity measurements clearly distinguish the Reuss and Voigt bulk moduli of olivine at all conditions. The consistency of volume and bulk modulus data is tested by fitting them simultaneously. Data collected at ambient pressure and data collected at ambient temperature up to 15 GPa are consistent with a Mie–Grünesien–Debye thermal-pressure EoS in combination with a third-order Birch–Murnaghan (BM) compressional EoS, the parameter V 0 = 43.89 cm3 mol?1, isothermal Reuss bulk modulus KTR,0=126.3(2) GPa, K?TR,0=4.54(6), a Debye temperature ?D=644(9)K, and a Grüneisen parameter ? 0 = 1.044(4), whose volume dependence is described by q = 1.9(2). High-pressure softening of the bulk modulus at room temperature, relative to this EoS, can be fit with a fourth-order BM EoS. However, recent high-P, T Brillouin measurements are incompatible with these EoS and the intrinsic physics implied by it, especially that (?K?TR?T)P>0. We introduce a new parameterisation for isothermal-type EoS that scales both the Reuss isothermal bulk modulus and its pressure derivative at temperature by the volume, KTR(T,P=0)=KTR,0[V0V(T)]?T and K?TR(T,P=0)=K?TR,0[V(T)V0]??, to ensure thermodynamic correctness at low temperatures. This allows the elastic softening implied by the high-P, T Brillouin data for mantle olivine to be fit simultaneously and consistently with the same bulk moduli and pressure derivatives (at room temperature) as the MGD EoS, and with the additional parameters of ? V0 = 2.666(9) × 10?5 K?1, ?E=484(6), ?T = 5.77(8), and ?? = ?3.5(1.1). The effects of the differences between the two EoS on the calculated density, volume, and elastic properties of olivine at mantle conditions and on the calculation of entrapment conditions of olivine inclusions in diamonds are discussed, and approaches to resolve the current uncertainties are proposed.-
DS201812-2853
2018
Angel, R.J.Murri, M., Mazzucchelli, M.L., Campomenosi, N., Korsakov, A.V., Prencipe, M., Mihailova, B.D., Scambelluri, M., Angel, R.J., Alvaro, M.Raman elastic geobarometry for anisotropic mineral inclusions. MirAmerican Mineralogist, Vol. 103, pp. 1869-1872.Russiamineral inclusions

Abstract: Elastic geobarometry for host-inclusion systems can provide new constraints to assess the pressure and temperature conditions attained during metamorphism. Current experimental approaches and theory are developed only for crystals immersed in a hydrostatic stress field, whereas inclusions experience deviatoric stress. We have developed a method to determine the strains in quartz inclusions from Raman spectroscopy using the concept of the phonon-mode Grüneisen tensor. We used ab initio Hartree-Fock/Density Functional Theory to calculate the wavenumbers of the Raman-active modes as a function of different strain conditions. Least-squares fits of the phonon-wavenumber shifts against strains have been used to obtain the components of the mode Grüneisen tensor of quartz (??m1 and ?m3?) that can be used to calculate the strains in inclusions directly from the measured Raman shifts. The concept is demonstrated with the example of a natural quartz inclusion in eclogitic garnet from Mir kimberlite and has been validated against direct X-ray diffraction measurement of the strains in the same inclusion.
DS201905-1063
2019
Angel, R.J.Nimis, P., Angel, R.J., Alvaro, M., Nestola, F., Harris, J.W., Casati, N., Marone, F.Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?Contributions to Mineralogy and Petrology, Vol. 174, p. 29- 13p.Russia, Siberiadeposit - Udachnaya

Abstract: We have studied by X-ray diffractometry the crystallographic orientation relationships (CORs) between magnesiochromite (mchr) inclusions and their diamond hosts in gem-quality stones from the mines Udachnaya (Siberian Russia), Damtshaa (Botswana) and Panda (Canada); in total 36 inclusions in 23 diamonds. In nearly half of the cases (n?=?17), [111]mchr is parallel within error to [111]diamond, but the angular misorientation for other crystallographic directions is generally significant. This relationship can be described as a case of rotational statistical COR, in which inclusion and host share a single axis (1 df). The remaining mchr-diamond pairs (n?=?19) have a random COR (2 df). The presence of a rotational statistical COR indicates that the inclusions have physically interacted with the diamond before their final incorporation. Of all possible physical processes that may have influenced mchr orientation, those driven by surface interactions are not considered likely because of the presence of fluid films around the inclusions. Mechanical interaction between euhedral crystals in a fluid-rich environment is therefore proposed as the most likely mechanism to produce the observed rotational COR. In this scenario, neither a rotational nor a random COR can provide information on the relative timing of growth of mchr and diamond. Some multiple, iso-oriented inclusions within single diamonds, however, indicate that mchr was partially dissolved during diamond growth, suggesting a protogenetic origin of these inclusions.
DS201912-2768
2019
Angel, R.J.Alvaro, M., Mazzucchelli, M.L., Angel, R.J., Murri, M., Campmenosi, N., Scambelluri, M., Nestola, F., Korsakov, A., Tomilenko, A.A., Marone, F., Morana, M.Fossil subduction recorded by quartz from the coesite stability field. GeobarometryGeology, in press, 5p. PdfRussia, Yakutiadeposit - Mir

Abstract: Metamorphic rocks are the records of plate tectonic processes whose reconstruction relies on correct estimates of the pressures and temperatures (P-T) experienced by these rocks through time. Unlike chemical geothermobarometry, elastic geobarometry does not rely on chemical equilibrium between minerals, so it has the potential to provide information on overstepping of reaction boundaries and to identify other examples of non-equilibrium behavior in rocks. Here we introduce a method that exploits the anisotropy in elastic properties of minerals to determine the unique P and T of entrapment from a single inclusion in a mineral host. We apply it to preserved quartz inclusions in garnet from eclogite xenoliths hosted in Yakutian kimberlites (Russia). Our results demonstrate that quartz trapped in garnet can be preserved when the rock reaches the stability field of coesite (the high-pressure and high-temperature polymorph of quartz) at 3 GPa and 850 °C. This supports a metamorphic origin for these xenoliths and sheds light on the mechanisms of craton accretion from a subducted crustal protolith. Furthermore, we show that interpreting P and T conditions reached by a rock from the simple phase identification of key inclusion minerals can be misleading.
DS201912-2804
2019
Angel, R.J.Mazzucchelli, M.L., Reali, A., Morganti, S., Angel, R.J., Alvaro, M.Elastic geobarometry for anistropic inclusions in cubic hosts. ( not specific to diamonds)Lithos, Vol. 350-351, 105218 11p. PdfMantlegeobarometry

Abstract: Mineral inclusions entrapped in other minerals may record the local stresses at the moment of their entrapment in the deep Earth. When rocks are exhumed to the surface of the Earth, residual stresses and strains may still be preserved in the inclusion. If measured and interpreted correctly through elastic geobarometry, they give us invaluable information on the pressures (P) and temperatures (T) of metamorphism. Current estimates of P and T of entrapment rely on simplified models that assumes that the inclusion is spherical and embedded in an infinite host, and that their elastic properties are isotropic. We report a new method for elastic geobarometry for anisotropic inclusions in quasi-isotropic hosts. The change of strain in the inclusion is modelled with the axial equations of state of the host and the inclusion. Their elastic interaction is accounted for by introducing a 4th rank tensor, the relaxation tensor, that can be evaluated numerically for any symmetry of the host and the inclusion and for any geometry of the system. This approach can be used to predict the residual strain/stress state developed in an inclusion after exhumation from known entrapment conditions, or to estimate the entrapment conditions from the residual strain measured in real inclusions. In general, anisotropic strain and stress states are developed in non-cubic mineral inclusions such as quartz and zircon, with deviatoric stresses typically limited to few kbars. For garnet hosts, the effect of the mutual crystallographic orientation between the host and the inclusion on the residual strain and stress is negligible when the inclusion is spherical and isolated. Assuming external hydrostatic conditions, our results suggest that the isotropic and the new anisotropic models give estimations of entrapment conditions within 2%.
DS201712-2687
2016
Angel, R.J. .Gonzales-Platas, J., Alvaro, M., Nestola, F., Angel, R.J. .EosFIT7-GUI: a new graphical user interface for equation of state calculations, analyses and teaching.Journal of Applied Crystallography, Vol. 49, pp. 1377-1382.Technologyanalyses

Abstract: EosFit7-GUI is a full graphical user interface designed to simplify the analysis of thermal expansion and equations of state (EoSs). The software allows users to easily perform least-squares fitting of EoS parameters to diffraction data collected as a function of varying pressure, temperature or both. It has been especially designed to allow rapid graphical evaluation of both parametric data and the EoS fitted to the data, making it useful both for data analysis and for teaching.
DS200512-0837
2005
Angeli, N.Penha, U.C., Karfunkel, J., Angeli, N.Diamondiferous deposits in the Jequitai area ( Minas Gerais, Brazil): a consequence of neotectonic processes.Neues Jahrbuch fur Geologie und Palaontologie , Band 236, Heft 1-2, pp. 207-224.South America, Brazil, Minas GeraisTectonics
DS200612-1070
2005
Angeli, N.Penha, U.C., Karfunkel, J., Angeli, N.Diamondiferous deposits in the Jequitai area (Minas Gerais, Brazil): a consequence of neotectonic processes.Neues Jahrbuch fur Geologie und Palaontologie , Vol. 236, 3, pp. 207-224.South America, Brazil, Minas GeraisTectonics - diamond deposit
DS1989-0885
1989
Angelica, R.Lima da Costa, M., Simoes, Angelica, R., Lima Lemos, R.Geochemical exploration on the Maicuru alkaline-ultramafic carbonatiticcomplexXiii International Geochemical Exploration Symposium, Rio 89 Brazilian Geochemical, pp. 62-64. AbstractBrazilCarbonatite, Maicuru
DS1991-0314
1991
Angelica, R.S.Costa, M.L., Fonseca, L.R., Angelica, R.S., Lemos, V.P., LemosGeochemical exploration of the Maicuru alkaline-ultramafic-carbonatitecomplex, northern BrasilJournal of Geochemical Exploration, Special Publications Geochemical Exploration, Vol. 40, No. 1-3, pp. 193-204GlobalCarbonatite, Maicuru
DS1991-0098
1991
Angelier, J.Bergerat, F., Angelier, J., Bouroz, C.Jointing analysis in the Colorado Plateau (USA) as a key to paleostressreconstruction. (in French)Comptes Rendus Academy of Science Series, (in French), Vol. 312, No. 3, pp. 309-316Colorado PlateauBlank
DS1996-0445
1996
Angelier, J.Faure, S., Tremblay, A., Angelier, J.Alleghanian paleostress reconstruction in Appalachians: intraplatede formation Laurentia and Gondwana.Geological Society of America (GSA) Bulletin., Vol. 108, No. 11, Nov. pp. 1467-80.Quebec, New BrunswickTectonics
DS201212-0176
2012
Angert, A.Dvir, O., Angert, A., Kessel, R.Determining the composition of C-H-O liquids following high-pressure and high-temperature diamond-trap experiments.Contributions to Mineralogy and Petrology, in press available 7p.TechnologyMantle, HP
DS201312-0233
2013
Angert, A.Dvir, O., Angert, A., Kessel, R.Determining the composition of C-H-O liquids following high pressure and high temperature diamond trap experiments.Contributions to Mineralogy and Petrology, Vol. 165, 3, pp. 593-599.MantleUHP
DS201812-2772
2018
Angiboust, S.Agard, P., Plunder, A., Angiboust, S., Bonnet, G., Ruh, J.The subduction plate interface: rock record and mechanical coupling ( from long to short timescales).Lithos, Vol. 320-321, pp. 537-566.Mantlesubduction

Abstract: Short- and long-term processes at or close to the subduction plate interface (e.g.,mineral transformations, fluid release, seismicity and more generally deformation) might be more closely related than previously thought. Increasing evidence from the fossil rock record suggests that some episodes of their long geological evolution match or are close to timescales of the seismic cycle. This contribution uses rocks recovered (episodically) from subduction zones, together with insights from thermomechanical modelling, to provide a new dynamic vision of the nature, structure and properties of the plate interface and to bridge the gap between the mechanical behavior of active subduction zones (e.g.,coupling inferred from geophysical monitoring) and fossil ones (e.g.,coupling required to detach and recover subducted slab fragments). Based on critical observations and an exhaustive compilation of worldwide subducted oceanic units (for which the presence near the plate interface, rock types, pressure, temperature, T/P gradients, thickness and timing of detachment can be assessed), the present study demonstrates how long-term mechanical coupling exerts a key control on detachment from the slab and potential rock recovery. Critical assessment of rock T/P characteristics indicates that these fragments can indeed be used as natural probes and provide reliable information on subduction interface dynamics down to ~2.8?GPa. Rock clusters are identified at depths of 30, 5560 and 80?km, with some differences between rock types. Data also reveal a first-order evolution with subduction cooling (in the first ~5?Myr), which is interpreted as reflecting a systematic trend from strong to weak mechanical coupling, after which subduction is lubricated and mostly inhibits rock recovery. This contribution places bounds on the plate interface constitution, regular thickness (<300?m; i.e. where/when there is no detachment), changing geometry and effective viscosity. The concept of ‘coupled thickness' is used here to capture subduction interface dynamics, notably during episodes of strong mechanical coupling, and to link long- and short-term deformation. Mechanical coupling depends on mantle wedge rheology, viscosity contrasts and initial structures (e.g.,heterogeneous lithosphere, existence of décollement horizons, extent of hydration, asperities) but also on boundary conditions (convergence rates, kinematics), and therefore differs for warm and cold subduction settings. Although most present-day subduction zone segments (both along strike and downdip) are likely below the detachment threshold, we propose that the most favorable location for detachment corresponds to the spatial transition between coupled and decoupled areas. Effective strain localization involves dissolution-precipitation and dislocation creep but also possibly brittle fractures and earthquakes, even at intermediate depths.
DS201909-2108
2019
Angiboust, S.Yamato, P., Duretz, T., Angiboust, S.Brittle/ductile deformation of eclogites: insights from numerical models.Geochemistry, Geophysics, Geosystems, Vol. 20, 7, pp. 3116-3133.mantleeclogites

Abstract: How rocks deform at depth during lithospheric convergence and what are the magnitudes of stresses they experience during burial/exhumation processes constitute fundamental questions for refining our vision of short?term (i.e., seismicity) and long?term tectonic processes in the Earth's lithosphere. Field evidence showing the coexistence of both brittle and ductile deformation at high pressure?low temperature (HP?LT) conditions particularly fuels this questioning. We here present 2D numerical models of eclogitic rock deformation by simple shear performed at centimeter scale. To approximate the eclogite paragenesis, we considered the deformed medium as composed of two mineral phases: omphacite and garnet. We run a series of models at 2.0 GPa and 550 °C for different background strain rates (from 10?14 s?1 to 10?8 s?1) and for different garnet proportions (from 0% to 55%). Results show that whole rock fracturing can occur under HP?LT conditions for strain rates larger than ~10?10 s?1. This suggests that observation of brittle features in eclogites does not necessarily mean that they underwent extreme strain rate. Care should therefore be taken when linking failure of eclogitic rocks to seismic deformation. We also explore the ranges of parameters where garnet and omphacite are deforming with a different deformation style (i.e., frictional vs viscous) and discuss our results in the light of naturally deformed eclogitic samples. This study illustrates that effective stresses sustained by rocks can be high at these P?T conditions. They reach up to ~1 GPa for an entirely fractured eclogite and up to ~500 MPa for rocks that contain fractured garnet.
DS1999-0014
1999
Anglin, C.D.Anglin, C.D., Harrison, J.C.Mineral resources, deposit models and assessmentGeological Survey of Canada (GSC) Open File, No. 3714, pp. E1-17. $ 50.00 (242p)Northwest Territories, NunavutExploration
DS1999-0458
1999
Anglin, C.D.McCurdy, M.W., Anglin, C.D., Spirito, W.A., Eddy, B.Geochemical surveys and interpretation. Briefly mentions diamondGeological Survey of Canada (GSC) Open File, No. 3714, pp. D1-34.. $ 50.00Northwest Territories, Nunavut, Bathurst IslandGeochemistry
DS200412-1533
2003
Anglin, L.Peter, J., Bleeker, W., Hulbert, J., Kerr, D., Ernst, R., Knight, R., Wright, D., Anglin, L.Slave Province minerals and geosciemce compilation and synthesis project.31st Yellowknife Geoscience Forum, p. 79. (abst.)Canada, Nunavut, Northwest TerritoriesOverview
DS1910-0002
1910
Angove, J.Angove, J.In the Early Days. the Reminiscences of Pioneer Life on The south African Diamond Fields.Kimberley And Johannesburg: Handel House., 213P.South AfricaKimberley, History
DS1988-0013
1988
Angus, J.C.Angus, J.C., Hayman, C.C.Low pressure metastable growth of diamond and 'diamondlike' phasesScience, Vol. 241, No. 4868, pp. 913-921GlobalDiamond synthesis
DS1992-0519
1992
Angus, J.C.Geis, M.W., Angus, J.C.Diamond film semiconductorsScientific American, Vol. 267, No. 4, October pp. 84-89GlobalLayman's overview CVD., Diamond film conductors
DS1993-0873
1993
Angus, J.C.Lambrecht, W.R., Lee, C.H., Segall, B., Angus, J.C., Sunkara, M.Diamond nucleation by hydrogenation of the edges of graphitic precursorsNature, Vol. 364, August 12, pp. 607-610.GlobalDiamond morphology
DS1993-0874
1993
Angus, J.C.Lambrect, W.R.L., Lee, C.H., Segall, B., Angus, J.C., Li, Z.Diamond nucleation by hydrogenation of the edges of graphitic precursorsNature, Vol. 364, No. 6438, August 12, pp. 607-610GlobalDiamond morphology, Graphite
DS201412-0012
2014
Angus, J.C.Angus, J.C.Diamond synthesis by chemical vapor deposition: the early years.Diamond and Related Materials, Vol. 49, pp. 77-86.TechnologyCVD
DS200612-0761
2006
Anh, T.T.Lan, C.Y., Izuka,T., Usuki, T., Wang, K.L., Anh, T.T., Van lOng ,T., O'Reilly, S.Y.Petrology and geochemistry of peridotite xenoliths from Vietnam Indochin a block.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 2. abstract only.ChinaXenolith - geochemistry
DS200612-1107
2005
Anhaesser, C.R.Poujol, M., Kiefer, R., Robb, L.J., Anhaesser, C.R., Armstrong, R.A.New U pb dat a on zircons from the Amalia greenstone belt southern Africa: insights into the Neoarchean evolution of the Kaapvaal Craton.South African Journal of Geology, Vol. 108, 3, pp. 317-332.Africa, South AfricaGeochronology
DS1970-0862
1974
Anhaeusser, C.R.Anhaeusser, C.R., Button, A.A Review of Southern African Stratiform Ore Deposits- Their position in Time and Space.Economic Geology Research Unit., INF. Circular No. 85, 45P.South Africa, BotswanaDiamonds, Review, Regional Geology
DS1987-0011
1987
Anhaeusser, C.R.Anhaeusser, C.R.Bibliography of theses in the Geological Sciences submitted to universities in Southern Africa, 1987Economic Geology Research Unit, Circular No. 195, 82pSouth AfricaBibliography, Theses
DS1992-0031
1992
Anhaeusser, C.R.Anhaeusser, C.R.A bibliography of the geology relating to the Barberton Mountain Land and surrounding granitic terrane 1986-1992Economic Geology Research Unit University of Witwatersrand, Information Circular No. 252, 44pSouth AfricaBarberton Mountain Land, Bibliography
DS1992-1073
1992
Anhaeusser, C.R.Minnett, R.C.A., Anhaeusser, C.R.Gravitational and diapiric structural history of the eastern portion of the Archean Murchison greenstone belt, South AfricaJournal of African Earth Sciences, Vol. 15, No. 3/4, October/November pp. 429-440South AfricaGreenstone belt, Geophysics -gravity
DS1993-0821
1993
Anhaeusser, C.R.Kisters, A.F.M., Anhaeusser, C.R.Fabric development, deformation of greenstone xenoliths in Archean TTG plutons and regional implications for the tectonic evolutionWitwatersrand Economic Geology Research Unit, Info. Circular No. 273, 28pSouth AfricaBarberton Greenstone Belt, Tectonics
DS1993-0899
1993
Anhaeusser, C.R.Lecuyer, C., Gruau, G., Anhaeusser, C.R., Fourcade, S.The origin of fluids and the effects of metamorphism on the primary chemical compositions of Barberton komatiites: new evidence from geochemistry, isotopesEconomic Geology Research Unit, University of the Witwatersrand, Inf. Circular No. 272, 32pSouth AfricaGeochemistry, Komatiites
DS1994-0918
1994
Anhaeusser, C.R.Kisters, A.F.M., Anhaeusser, C.R.The structural significance of the Steynsdorp pluton and anticline withIn the tectono-magmatic frameworkEconomic Geology Research Unit, University of Witwatersrand, I.C. No. 279, 18pSouth AfricaStructure, tectonics, Barberton Mountain Land
DS1994-1011
1994
Anhaeusser, C.R.Lecuyer, C., Gruau, G., Anhaeusser, C.R., Fourcade, S.The origin of fluids and effects of metamorphism on the primary chemical compositions of Barberton komatiites: new evidenceGeochimica et Cosmochimica Acta, Vol. 58, No. 2, January pp. 1043South AfricaGeochemistry, Geochronology
DS1995-0966
1995
Anhaeusser, C.R.Kisters, A.F.M., Anhaeusser, C.R.Emplacement features of Archean TTG plutons along the southern margin Of the Barberton greenstone beltPrecambrian Research, Vol. 75, No. 1-2, Nov. 1, pp. 1-46South AfricaTrondjhemite, Barberton greenstone belt
DS1997-0034
1997
Anhaeusser, C.R.Anhaeusser, C.R., Walraven F.Polyphase crustal evolution of the Archean Kraaipan granite greenstoneterrane, Kaapvaal CratonEconomic Geology Research Unit, No. 313, 27pSouth AfricaGephysics - Bouguer gravity, Granite greenstone belts
DS1998-0758
1998
Anhaeusser, C.R.Kisters, A.F.M., Gibson, R.L., Anhaeusser, C.R.The role of strain localization in the segregation and ascent of anatecticmelts, Namaqualand, South AfricaJournal of Struct. Geol, Vol. 20, No. 2-3, Feb.1, pp. 229-42South AfricaTectonics
DS1998-1585
1998
Anhaeusser, C.R.Wilson, M.G.C., Anhaeusser, C.R.The mineral resources of South Africa. Sixth editionSouth Africa Council, Handbook # 16, pp. 1-10.South AfricaEconomic geology, Minerals industry - overview
DS2002-1277
2002
Anhaeusser, C.R.Poujol, M., Robb, L.J., Anhaeusser, C.R., Gericke, B.Geochronologic constraints on the evolution of the Kaapvaal Craton, South AfricaEconomic Geology Research Institute, EGRU Wits, Information Circular, No. 360, 37p.South AfricaGeochronology, craton, terrane, magmatism - not specific to diamonds
DS2003-1098
2003
Anhaeusser, C.R.Poujol, M., Robb, L.J., Anhaeusser, C.R., Gericke, B.A review of the geochronological constraints on the evolution of the Kaapvaal CratonPrecambrian Research, Vol. 127, 1-2, Nov. pp. 181-213.South AfricaGeochronology
DS200412-1573
2003
Anhaeusser, C.R.Poujol, M., Robb, L.J., Anhaeusser, C.R., Gericke, B.A review of the geochronological constraints on the evolution of the Kaapvaal Craton, South Africa.Precambrian Research, Vol. 127, 1-2, Nov. pp. 181-213.Africa, South AfricaGeochronology
DS200412-1589
2004
Anhaeusser, C.R.Prevec, S.A., Anhaeusser, C.R., Poujol, M.Origin and evolution of late mafic dykes in an Archean gneissic assemblage, Kaapvaal Craton, South Africa.Economic Geology Research Institute Information Circular, Information Circular 380, 11p.Africa, South AfricaEcologitic lithosphere, lamprophyres
DS200512-0022
2004
Anhaeusser, C.R.Anhaeusser, C.R.Paleoarchean to Mesoproterozoic (c.3500-1000Ma) ultramafic to mafic intrusions of the Kaapvaal Craton and neighbouring metamorphic belts: a review.Economic Geology Research Institute Information Circular, No. 384, 59p.Africa, South AfricaLimpopo Belt, Madison, Mpumalanga, Namaqua
DS200512-0875
2004
Anhaeusser, C.R.Prevec, S.A., Anhaeusser, C.R., Poujot, M.Evidence for Archean lamprophyres from the Kaapvaal Craton, South Africa.South African Journal of Science, Vol. 100, 11/12, pp. 549-555.Africa, South AfricaLamprophyre
DS200612-0028
2006
Anhaeusser, C.R.Anhaeusser, C.R.A reevaluation of subduction related accretionary terrane boundaries on the Kaapvaal Craton, South Africa: collisional suture zones?Geological Society of America, Processes on the Earth, Special Paper 405, Chapter 11.Africa, South AfricaSubduction
DS200612-0626
2006
Anhaeusser, C.R.Ishihara, S., Ohmoto, H., Anhaeusser, C.R., Imai, A., Robb, L.J.Discovery of the oldest oxidized granitoids in the Kaapvaal Craton and its implications for the redox evolution of early Earth.Geological Society of America Memoir, No. 198, pp. 67-80.Africa, South AfricaRedox
DS200612-0645
2006
Anhaeusser, C.R.Johnson, M.R., Anhaeusser, C.R., Thomas, R.J.The geology of South Africa. Chapter 31 Kimberlites by E.M.W. SkinnerCouncil of Geoscience and Geological Society of South Africa joint venture, anhaeusserc @geosciences.wits.ac.zaAfrica, South AfricaBook - Archean, Proterozoic, Phanerozoic, general
DS201503-0181
2015
Anhaeusser, C.R.Van Kranendonk, M.J., Smithies, R.H., Griffin, W.L., Huston, D.L., Hickman, A.H., Champion, D.C., Anhaeusser, C.R., Pirajno, F.Making it thick: a volcanic plateau origin of Paleoarchean continental lithosphere of the Pilbara and Kaapvaal cratons.Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 83-111.Australia, Africa, South AfricaGeotectonics
DS1993-0035
1993
Anhauesser, C.R.Anhauesser, C.R.Bibliography of theses in the geological sciences submitted to universities in South Africa, 1993Economic Geology Research Unit, University of Witwatersrand, Information Circular No. 270, 66pSouth AfricaBibliography, Theses
DS1960-0541
1965
Anikeyeva, L.I.Epshteyn, YE.M., Anikeyeva, L.I.Problems in Geology and Petrology of Ultrabasic Alkalic Rock Complexes.International Geology Review, Vol. 7, No. 2, PP. 307-324.RussiaTunguska Synclise, Melilite, Kimberlite
DS201412-0307
2014
Anikin, L.P.Gordeev, E.I., Karpov, G.A., Anikin, L.P., Krivovichev, S.V., Filatov, S.K., Antonov, A.V., Ovsyannikov, A.A.Diamonds in lavas of the Tolbachik fissure eruption in Kamchatka.Doklady Earth Sciences, Vol. 454, 1, pp. 47-49.RussiaTolbachik fissure
DS201604-0612
2016
Anikin, L.P.Kaminisky, F.V., Wirth, R., Anikin, L.P., Morales, L., Schreiber, A.Carbonado-like diamond from the Avacha active volcano in Kamchatka, Russia.Lithos, in press available, 15p.RussiaCarbonado

Abstract: In addition to a series of finds of diamond in mafic volcanic and ultramafic massive rocks in Kamchatka, Russia, a carbonado-like diamond aggregate was identified in recent lavas of the active Avacha volcano. This aggregate differs from ‘classic carbonado’ by its location within an active volcanic arc, well-formed diamond crystallites, and cementing by Si-containing aggregates rather than sintering. The carbonado-like aggregate contains inclusions of Mn-Ni-Si-Fe alloys, native ?-Mn, tungsten and boron carbides, which are uncommon for both carbonado and monocrystalline diamonds. Mn-Ni-Si-Fe alloys, trigonal W2C and trigonal B4C are new mineral species that were not previously found in the natural environment. The formation of the carbonado-like diamond aggregate started with formation at ~ 850-1000 °C of tungsten and boron carbides, Mn-Ni-Si-Fe alloys and native ?-Mn, which were used as seeds for the subsequent crystallization of micro-sized diamond aggregate. In the final stage, the diamond aggregate was cemented by amorphous silica, tridymite, ?-SiC, and native silicon. The carbonado-like aggregate was most likely formed at near-atmospheric pressure conditions via the CVD mechanism during the course or shortly after one of the volcanic eruption pulses of the Avacha volcano. Volcanic gases played a great role in the formation of the carbonado-like aggregate.
DS201612-2310
2016
Anikin, L.P.Kaminsky, F.V., Wirth, R., Anikin, L.P., Morales, L., Schreiber, A.Carbonado-like diamond from the Avacha active volcano in Kamchatka, Russia.Lithos, Vol. 265, pp. 222-236.RussiaCarbonado

Abstract: Abstract In addition to a series of finds of diamond in mafic volcanic and ultramafic massive rocks in Kamchatka, Russia, a carbonado-like diamond aggregate was identified in recent lavas of the active Avacha volcano. This aggregate differs from ‘classic carbonado’ by its location within an active volcanic arc, well-formed diamond crystallites, and cementing by Si-containing aggregates rather than sintering. The carbonado-like aggregate contains inclusions of Mn-Ni-Si-Fe alloys, native ?-Mn, tungsten and boron carbides, which are uncommon for both carbonado and monocrystalline diamonds. Mn-Ni-Si-Fe alloys, trigonal W2C and trigonal B4C are new mineral species that were not previously found in the natural environment. The formation of the carbonado-like diamond aggregate started with formation at ~ 850-1000 °C of tungsten and boron carbides, Mn-Ni-Si-Fe alloys and native ?-Mn, which were used as seeds for the subsequent crystallization of micro-sized diamond aggregate. In the final stage, the diamond aggregate was cemented by amorphous silica, tridymite, ?-SiC, and native silicon. The carbonado-like aggregate was most likely formed at near-atmospheric pressure conditions via the CVD mechanism during the course or shortly after one of the volcanic eruption pulses of the Avacha volcano. Volcanic gases played a great role in the formation of the carbonado-like aggregate.
DS201807-1501
2018
Anikin, L.P.Kaminsky, F.V., Wirth, R., Anikin, L.P., Morales, L., Schreiber, A.Carbonado like diamond from the Avacha active volcano in Kamchatka, Russia.Lithos, in press available, 57p.Russiacarbonado

Abstract: In addition to a series of finds of diamond in mafic volcanic and ultramafic massive rocks in Kamchatka, Russia, a carbonado-like diamond aggregate was identified in recent lavas of the active Avacha volcano. This aggregate differs from 'classic carbonado' by its location within an active volcanic arc, well-formed diamond crystallites, and cementing by Si-containing aggregates rather than sintering. The carbonado-like aggregate contains inclusions of Mn-Ni-Si-Fe alloys, native ?-Mn, tungsten and boron carbides, which are uncommon for both carbonado and monocrystalline diamonds. Mn-Ni-Si-Fe alloys, trigonal W2C and trigonal B4C are new mineral species that were not previously found in the natural environment. The formation of the carbonado-like diamond aggregate started with formation at 850-1000 °C of tungsten and boron carbides, Mn-Ni-Si-Fe alloys and native ?-Mn, which were used as seeds for the subsequent crystallization of micro-sized diamond aggregate. In the final stage, the diamond aggregate was cemented by amorphous silica, tridymite, ?-SiC, and native silicon. The carbonado-like aggregate was most likely formed at near-atmospheric pressure conditions via the CVD mechanism during the course or shortly after one of the volcanic eruption pulses of the Avacha volcano. Volcanic gases played a great role in the formation of the carbonado-like aggregate.
DS201902-0282
2019
Anikin, L.P.Kaminsky, F., Wirth, R., Anikin, L.P., Schreiber, A.Kamchatite diamond aggregate from northern Kamchatka, Russia: new find of diamond formed by gas phase condensation or chemical vapor deposition.American Mineralogist, Vol. 104, pp. 140-149.Russia, Kamchatkamineralogy

Abstract: A series of polycrystalline diamond grains were found within the Valizhgen Peninsula in Koryakia, northern Kamchatka, Russia. A grain from the Aynyn River area is studied in detail with TEM. Diamond crystallites, 2-40 ?m in size are twinned and have high dislocation density. They are cemented with tilleyite Ca5(Si2O7)(CO3)2, SiC, Fe-Ni-Mn-Cr silicides, native silicon, graphite, calcite, and amorphous material. Among SiC grains, three polymorphs were discriminated: hexagonal 4H and 6H and cubic C3 (?-SiC). Silicides have variable stoichiometry with (Fe,Ni,Mn,Cr)/Si = 0.505-1.925. Native silicon is an open-framework allotrope of silicon S24, which has been observed, to date, as a synthetic phase only; this is a new natural mineral phase. Three types of amorphous material were distinguished: a Ca-Si-C-O material, similar in composition to tilleyite; amorphous carbon in contact with diamond, which includes particles of crystalline graphite; and amorphous SiO2. No regularity in the distribution of the amorphous material was observed. In the studied aggregate, diamond crystallites and moissanite are intensively twinned, which is characteristic for these minerals formed by gas phase condensation or chemical vapor deposition (CVD) processes. The synthetic analogs of all other cementing compounds (?-SiC, silicides, and native silicon) are typical products of CVD processes. This confirms the earlier suggested CVD mechanism for the formation of Avacha diamond aggregates. Both Avacha and Aynyn diamond aggregates are related not to "classic" diamond locations within stable cratons, but to areas of active and Holocene volcanic belts. The studied diamond aggregates from Aynyn and Avacha, by their mineralogical features and by their origin during the course of volcanic eruptions via a gas phase condensation or CVD mechanism, may be considered a new variety of polycrystalline diamond and may be called "kamchatite". Kamchatite extends the number of unusual diamond localities. It increases the potential sources of diamond and indicates the polygenetic character of diamond.
DS202005-0731
2020
Anikin, L.P.Galimov, E.M., Kaminsky, F.V., Shilobreeva, S.N., Sevastyanov, V.S., Voropaev, S.A., Khachatryan, G.K., Wirth, R., Schreiber, A., Saraykin, V.V., Karpov, G.A., Anikin, L.P.Enigmatic diamonds from the Tolbachik volcano, Kamchatka.American Mineralogist, Vol. 105, pp. 498-509. pdfRussiadeposit - Tolbachik

Abstract: Approximately 700 diamond crystals were identified in volcanic (mainly pyroclastic) rocks of the Tolbachik volcano, Kamchatka, Russia. They were studied with the use of SIMS, scanning and transmission electron microscopy, and utilization of electron energy loss spectroscopy and electron diffraction. Diamonds have cube-octahedral shape and extremely homogeneous internal structure. Two groups of impurity elements are distinguished by their distribution within the diamond. First group, N and H, the most common structural impurities in diamond, are distributed homogeneously. All other elements observed (Cl, F, O, S, Si, Al, Ca, and K) form local concentrations, implying the existence of inclusions, causing high concentrations of these elements. Most elements have concentrations 3-4 orders of magnitude less than chondritic values. Besides N and H, Si, F, Cl, and Na are relatively enriched because they are concentrated in micro- and nanoinclusions in diamond. Mineral inclusions in the studied diamonds are 70-450 nm in size, round- or oval-shaped. They are represented by two mineral groups: Mn-Ni alloys and silicides, with a wide range of concentrations for each group. Alloys vary in stoichiometry from MnNi to Mn2Ni, with a minor admixture of Si from 0 to 5.20-5.60 at%. Silicides, usually coexisting with alloys, vary in composition from (Mn,Ni)4Si to (Mn,Ni)5Si2 and Mn5Si2, and further to MnSi, forming pure Mn-silicides. Mineral inclusions have nanometer-sized bubbles that contain a fluid or a gas phase (F and O). Carbon isotopic compositions in diamonds vary from -21 to -29‰ ?13CVPDB (avg. = -25.4). Nitrogen isotopic compositions in diamond from Tolbachik volcano are from -2.32 to -2.58‰ ?15NAir. Geological, geochemical, and mineralogical data confirm the natural origin of studied Tolbachik diamonds from volcanic gases during the explosive stage of the eruption.
DS1992-0588
1992
Anil KumarGopalen, K., Anil KumarPrecise rubidium-strontium (Rb-Sr) ages of South Indian kimberlites and Central IndianlamproitesInternational Roundtable Conference on Diamond Exploration and Mining, held, p. 98. abstract onlyIndiaGeochronology, isotopes, Kimberlites
DS200812-0857
2008
Anilkumar, Y.Patel, S.C., Ravi, S., Anilkumar, Y., Naik, A., Thakur, S.S., Pati, J.K.Mafic xenoliths in Proterozoic kimberlites from eastern Dharwar Craton, India: mineralogy and P-T regime.Journal of Asian Earth Sciences, Vol. 34, 3, pp. 336-346.IndiaDeposit - Wajrakur
DS201012-0565
2010
Anilkumar, Y.Patel, S.C., Ravi, S., Anilkumar, Y., Pati, J.K.Major element composition of concentrate garnets in Proterozoic kimberlites from the eastern Dharwar Craton, India: implications on sub-continental lithospheric mantle.Journal of Asian Earth Sciences, Vol. 39, 6, pp. 578-588.IndiaWajrakarur, Narayanpet
DS200512-0013
2004
Anim Sackey, C.Amankwah, R.K., Anim Sackey, C.Strategies for sustainable development of small scale gold and diamond mining of Ghana.Resources Policy, Vol. 29, 3-4, pp. 131-138.Africa, GhanaEconomics - sustainable
DS202104-0611
2021
Anisimov, A.N.Titkov, S.V., Yakovleva, V.V., Breev, I.D., Anisimov, A.N., Baranov, P.G., Dorofeeva, A.I., Bortnikov, N.S.Distribution of nitrogen-vacancy NV centers in cubic diamond crystals from Anabar placers as revealed by ODMR and PL tomography.Doklady Earth Sciences, Vol. 496, 1, pp. 45-47. pdfRussiadeposit - Anabar

Abstract: Nitrogen-vacancy NV- centers, which are of considerable interest for quantum electronics, are artificially produced in the diamond structure by irradiation and subsequent annealing. In this work, these centers were revealed in natural diamonds of cubic habit (type IaA + Ib according to physical classification) from an industrial placer deposit of the Anabar River (NE Siberian platform) using the method of optically detected magnetic resonance (ODMR). Localization of the NV- centers in the dislocations slip planes {111}, separated by distances of about 5 ?m, was established by means of scanning the ODMR and PL signals with a submicron resolution. In various crystals, one or two intersecting systems of such slip planes have been revealed. The largest amounts of these defects were found in the peripheral zones of crystals containing increased amounts of single isomorphic nitrogen atoms in the structure. The data obtained indicate the formation of the NV- centers in natural diamonds under post-crystallization plastic deformation, i.e., by a mechanism that differs from the widely used method of their artificial production.
DS1997-0140
1997
Anisimov, I.S.Bulakh, A.G., Nesterov, A.R., Anisimov, I.S., Williams, C.Sevlyavr carbonatite complex, Kola Peninsula, RussiaGeological Association of Canada (GAC) Abstracts, POSTER.Russia, Kola PeninsulaCarbonatite, Deposit - Sevlyavr
DS1998-0182
1998
Anisimov, I.S.Bulakh, A.G., Nesterov, A.R., Anisimov, I.S.Zirkelite from Seblyavr carbonatite complex, Kola Peninsula- xray and electron microprobe study metamictMineralogical Magazine, Vol. 62, No. 6, Dec. 1, pp. 837-46.Russia, Kola PeninsulaCarbonatite, Deposit - Seblyavr
DS201412-0473
2014
Anisimova, I.Korikovsky, S., Kotov, A., Salnikova, E., Aranovich, L., Korpechkov, D., Yakovleva, S., Tolmacheva, E., Anisimova, I.The age of the protolith of metamorphic rocks in the southeastern Lapland granulite belt, southern Kola Peninsula: correlation with the Belomorian mobile belt in the context of the problem of Archean eclogites.Petrology, Vol. 22, 2, pp. 91-108.Russia, Kola PeninsulaEclogite
DS201212-0158
2012
AnismovaDegtyarev, K.E., Tretyakov, Kotov, Salnikova, Shatagi, Yakovleva, Anismova, PlotkinaThe Chelkar peridotite-gabbronorite pluton ( Kokchetav massif, northern Kazakhstan): formation type and geochronology.Doklady Earth Sciences, Vol. 446, 2, pp. 1162-1166.Russia, KazakhstanGeochronlogy
DS1992-0033
1992
Anistratov, K.Yu.Anistratov, Yu.I., Anistratov, K.Yu.Surface mining of diamond deposits in the severe conditions of YakutianNorth.Mining in the Arctic, Editors Bandopadhyay and Nelson, Balkema Publishing, pp. 23-27.Russia, YakutiaMining, Deposit - Mir, Udachnaya, International, Yubileunaya
DS1992-0032
1992
Anistratov, Yu.I.Anistratov, Yu.I.Surface mining of native diamond deposits in severe conditions of YakutianNorthSecond International Symposium on Mining in the Arctic, to be held July, listing of paper topic onlyRussia, YakutiaAlluvial mining
DS1992-0033
1992
Anistratov, Yu.I.Anistratov, Yu.I., Anistratov, K.Yu.Surface mining of diamond deposits in the severe conditions of YakutianNorth.Mining in the Arctic, Editors Bandopadhyay and Nelson, Balkema Publishing, pp. 23-27.Russia, YakutiaMining, Deposit - Mir, Udachnaya, International, Yubileunaya
DS201012-0716
2010
Anjaiah, K.V.Singh, S.P., Balaram, V., Satyanarayanan, M., Anjaiah, K.V., Kharia, A.Platinum group elements in basic and ultrabasic rocks around Madawara Bundelk hand Massif, Central India.Current Science, Vol. 99, 3, August 16, 9p.IndiaPGE melting - not specific to diamonds
DS201012-0717
2010
Anjaiah, K.V.Singh, S.P., Balaram, V., Satyanarayanan, M., Anjaiah, K.V., Kharia, A.Platinum group elements in basic and ultrabasic rocks around Madawara Bundelk hand Massif, Central India.Current Science, Vol. 99, 3, August 16, 9p.IndiaPGE melting - not specific to diamonds
DS2003-0086
2003
Ankar, E.Baumgartner, M., Ankar, E., Grutter, H.Compositional classification of kimberlitic and non-kimberlitic ilmenite with implications8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, AbstractGlobalDiamond exploration - mineralogy
DS200412-0113
2003
Ankar, E.Baumgartner, M., Ankar, E., Grutter, H.Compositional classification of kimberlitic and non-kimberlitic ilmenite with implications for visual selection and discriminati8 IKC Program, Session 8, AbstractTechnologyDiamond exploration - mineralogy
DS1996-1334
1996
Annan, A.P.Smith, R.S., Annan, A.P., Lemieux, J., Pederson, R.N.Application of a modified GEOTEM (R) system to reconnaissance exploration for kimberlites Point LakeGeophysics, Vol. 61, No. 1, Jan-Feb. pp. 82-92.Northwest TerritoriesGeophysics -GEOTEM., Kimberlites -Point Lake
DS1992-0034
1992
Annan, P.Annan, P., Liemieux, J., Pederson, R.Geotem as applied to the search for kimberlitesNorthwest Territories Geoscience Forum held November 25, 26th. 1992, Poster, AbstractNorthwest TerritoriesGeophysics - GeoteM.
DS1975-1215
1979
Annegarn, H.J.Sellschop, J.P.F., Madiba, C.C.P., Annegarn, H.J.Volatile Light Elements in DiamondDiamond Research, VOLUME FOR 1979, PP. 24-30.GlobalDiamond Genesis, Microprobe
DS1989-0891
1989
Annells, R.N.Litherland, M., Annells, R.N., Darbyshire, D.P.F., Fletcher, C.J.N.The Proterozoic of Eastern Bolivia and its relationship to the Andean mobile beltPrecambrian Research, Vol. 43, pp. 157-174Andes, BoliviaProterozoic, Tectonics
DS1997-0035
1997
Annels, A.Annels, A.Ore reserves: errors and classificationAssaying and Reporting Conference Nov. 10-11, 1997 Singapore, 29pGlobalSampling, assaying, ore reserves, discoveries, Geostatistics, gold
DS2003-0344
2003
Annels, A.Dominy, S., Annels, A.Core recovery for mineral resource estimation - some considerationsEgru Newsletter, April pp. 6-9.GlobalMineral resources - not specific to diamonds
DS200412-0467
2003
Annels, A.Dominy, S., Annels, A.Core recovery for mineral resource estimation - some considerations.Economic Geology Research Institute, April pp. 6-9.TechnologyMineral resources - not specific to diamonds
DS1991-0025
1991
Annels, A.E.Annels, A.E.Mineral deposit evaluation -a practical approachChapman and Hall, 450pGlobalBook -table of contents, Mineral deposit evaluation
DS1992-0035
1992
Annels, A.E.Annels, A.E.Case histories and methods in mineral resource evaluationGeological Society of London Special Publication, No. 63, approx. 120.00 United StatesBookEconomics, Ore reserves, geostatistics, case histories, gold, nickel
DS2003-0020
2003
Annels, A.E.Annels, A.E., Dominy, S.C.Core recovery and quality: important factors in mineral resource estimation. ( goldApplied Earth Science Transactions Institute Mining and Metallurgy, Vol. 112, Dec. pp. B 305-312.GlobalBlank
DS200412-0042
2003
Annels, A.E.Annels, A.E., Dominy, S.C.Core recovery and quality: important factors in mineral resource estimation. ( gold related)Applied Earth Science Transactions Institute of Mining and Metallurgy, Vol. 112, Dec. pp. B 305-312.TechnologyEconomics - resource estimation - not specific to diamo
DS200412-0468
2004
Annels, A.E.Dominy, S.C., Noppe, M.A., Annels, A.E.Errors and uncertainty in mineral resource and ore reserve estimation: the importance of getting it right.Exploration and Mining Geology, Vol.11,1-4,Jan-Oct.2002, publ. Apr. 29,2004 pp. 77-98TechnologyEvaluation - not specific to diamonds
DS2001-0037
2001
Annen, C.Annen, C., Lanat, J-F., Provost, A.The long term growth of volcanic edifices: numerical modelling of the roleof dike intrusion and lava flow..Journal of Volcan. Geotherm Res., Vol. 105, pp. 263-89.GlobalDyke intrusions - not specific to diamond
DS2002-0047
2002
Annen, C.Annen, C., Sparks, R.S.Effects of repetitive emplacement of basaltic intrusions on thermal evolution and melt generation in the crust.Earth and Planetary Science Letters, Vol. 203, 3-4, pp. 937-55.MantleMelting - heat flow
DS200612-0029
2006
Annen, C.Annen, C., Blundy, J.D., Sparks, R.S.J.The genesis of intermediate and silicic magmas in deep crustal hot zones.Journal of Petrology, Vol. 47, 3, pp. 505-539.MantleMagmatism - not specific to diamonds
DS200812-0038
2008
Annen, C.Annen, C.From intrusions to magma chambers: conditions for the accumulation of magma in the upper crust.Goldschmidt Conference 2008, Abstract p.A27.MantleMagmatism
DS201212-0687
2012
Annen, C.Solano, J.M.S., Jackson, M.D., Sparks, R.S.J., Blundy, J.D., Annen, C.Melt segregation in deep crustal hot zones: a mechanism for chemical differentiation, crustal assimilation and the formation of evolved magmas.Journal of Petrology, Vol. 53, 10, pp. 1999-2026.MantleHotspots, magmatism
DS201412-0099
2014
Annen, C.Caricchi, L., Annen, C., Blundy, J., Simpson, G., Pinel, V.Supervolcanoes erupt by their own rules. Mega-eruptions and smaller volcanoes are triggered by different mechanisms.Nature Geoscience, Jan. 5, 2p.MantleVolcanoes
DS201605-0812
2016
Annen, C.J.Blundy, J.D., Annen, C.J.Enigmatic relationship between silicic volcanic and plutonic rocks: crustal magmatic systems from the perspective of heat transfer.Elements, Vol. 12, pp. 115-120.TechnologyMagmatism
DS200612-0754
2006
Annersten, H.Kuskov, O.L., Kronrod, V.A., Annersten, H.Inferring upper mantle temperatures from seismic and geochemical constraints: implications for Kaapvaal Craton.Earth and Planetary Science Letters, Vol. 244, 1-2, Apr. 15, pp. 133-154.Africa, South AfricaGeothermometry
DS2002-0048
2002
Annesley, I.R.Annesley, I.R.Timing and P T conditions of Paleoproterozoic metamorphism crustal melting, magmatism, deformationGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.2., p.2.SaskatchewanTectonics - Hearne Province
DS2002-0049
2002
Annesley, I.R.Annesley, I.R.Timing and P T conditions of Paleoproterozoic metamorphism crustal melting, magmatism, deformationGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.2., p.2.SaskatchewanTectonics - Hearne Province
DS200512-0674
2005
Annesley, I.R.Madore, C., Annesley, I.R., Portella, P.Geology and thermotectonic evolution of the western margin of the Trans-Hudson Orogen: evidence from the eastern sub-Athabasca basement, Saskatchewan.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 573-597.Canada, SaskatchewanGeothermometry
DS1995-0415
1995
Annikova, I.Yu.Dergachev, V.B., Annikova, I.Yu.Ongonite like dikes in the Zashikha rare metal deposit, East SayanDoklady Academy of Sciences Acad. Science Russia, Vol. 3331, No. 9, Sept. pp. 70-73RussiaTopaz, rare metals
DS1990-1131
1990
Annor, A.E.Olasehinde, P.I., Pal, P.C., Annor, A.E.Aeromagnetic anomalies and structural lineaments in the Nigerian BasementComplexJournal of African Earth Sciences, Vol. 11, No. 3/4, pp. 351-356NigeriaGeophysics -magnetics, Tectonics
DS1987-0604
1987
Annual General report for 1980-1981Records of the Geological Survey India, Annual General report for 1980-1981Records of the Geological Survey of India, for 1980-1981,Mizapur district.Jungel Integrated explorationprojectRecords of the Geological Survey India, Annual General report for 1980-1981, Vol. 115, pt. 1, p. 145IndiaMizapur
DS1997-0036
1997
Annual ReviewsAnnual ReviewsHydrologic processes from catchment to continental scalesAnnual Reviews, GlobalBook - ad, Hydrology, geomorphology, brine
DS1997-0037
1997
Annual ReviewsAnnual ReviewsOrigin of planets and lifeAnnual Reviews, GlobalBook - ad, Planets and Life
DS1990-0558
1990
Annual Technical Report for 1989Geological Survey of South Africa, Annual Technical Report for 1989Schuller kimberliteGeological Survey of South Africa, Annual Technical Report for 1989, p. 106South AfricaBrief description of project, Schuller
DS1860-0075
1869
Anon.Anon.Key to Precious Stones and MetalsLondon:, Africa, South AfricaGeology
DS1860-0076
1869
Anon.Anon.The Diggers Practical Guide: Orange and Vaal riversPamphlet., 10P.Africa, South AfricaHistory, Alluvials
DS1860-0097
1870
Anon.Anon.The South African Diamond Fields (1870) Vaal RiverLondon: E. Stanford., 46P.Africa, South Africa, Cape ProvinceAlluvials
DS1860-0352
1881
Anon.Anon.Georgia Diamonds #1South , Vol. 21, No. 1, JULY P. 12.United States, Georgia, AppalachiaDiamond Occurrence
DS1860-0376
1882
Anon.Anon.Diamond in GeorgiaSouth, Vol. 23, No. 3, P. 19.United States, Georgia, AppalachiaDiamond Occurrence
DS1860-0399
1883
Anon.Anon.Diamantengrabereien in Sued-afrikaZeitschr. Deut. Ing. Arch. Verhandl., Vol. 27, P. 565.South Africa, Griqualand West, Kimberley MineMining engineering
DS1860-0405
1883
Anon.Anon.Gems and Gem HuntingNewspaper Clipping Unknown., United States, North CarolinaProspecting
DS1860-0585
1888
Anon.Anon.Have We Found Diamonds Amongst United States?Waterbury, JANUARY PP. 99-100.United States, KentuckyDiamond Occurrence
DS1860-0685
1891
Anon.Anon.Onze Nijverheid in Zuid AfrikaTijd. Nederl. Maat., Africa, South AfricaGeology
DS1860-0922
1896
Anon.Anon.The Diamond FieldNorth Adams, MassachusettsTranscript., APRIL 2ND.United States, Massachusetts, AppalachiaDiamond Occurrence
DS1860-1014
1898
Anon.Anon.Diamant Production #1Zeitschr. F. Prakt. Geol., Vol. 6, P; 180.Africa, South AfricaDiamond Production
DS1860-1054
1899
Anon.Anon.Diamonds in Shantung, 1898The Mineral Industry During 1898, Vol. 7, P. 275.China, ShandongDiamond Occurrence
DS1860-1060
1899
Anon.Anon.Diamant Production #4Zeitschr. F. Prakt. Geol., Vol. 7, P. 236.Africa, South Africa, GlobalProduction
DS1860-1063
1899
Anon.Anon.Diamonds; the Mineral Industry During 1898 De Beers, Wesselton, Schuller, Montrose, CarbonadoThe Mineral Industry During 1898, Vol. 7, PP. 273-276.South Africa, Griqualand West, Transvaal, Mozambique, Brazil, EastProduction
DS1910-0003
1910
Anon.Anon.Diamond from Sky. Wonderfully Beautiful Gem Found in Hole Cleft by thunderbolt.Bristol Virginia: Herald Courier., APRIL 27TH.GlobalMeteorite, Diamonds
DS1910-0004
1910
Anon.Anon.Diggers and over PeggingSouth Africa, Vol. 86, Apr. 2ND. P. 17.South AfricaAlluvial Diamond Placers, Prospecting
DS1910-0005
1910
Anon.Anon.An Interesting DiamondSouth Africa, Vol. 85, Jan. 8TH. P. 91.South AfricaBort, Mineralogy, Diamonds Notable
DS1910-0006
1910
Anon.Anon.The Schuller Diamond Mine Redivivus. Some Interesting History of the National Diamond Syndicate its Present Position And a Full Description of the Property.South African Mining Journal, Vol. 8, PT. 1, JUNE 11TH. No. 379, PP. 427-429.South AfricaCurrent Activities, History, Rayton, Production, Mining Economic
DS1910-0007
1910
Anon.Anon.New Jagersfontein and the Diamond OutlookSouth African Mining Journal, Vol. 8, PT. 1, JULY 2ND. No. 382, P. 506.South AfricaCurrent Activities, Mineral Resources, Production
DS1910-0008
1910
Anon.Anon.Diamond News of SincuraHunt's Magazine., Vol. 15, P. 600.South AfricaCurrent Actvities
DS1910-0009
1910
Anon.Anon.Diamonds Near VitanhagsSouth African Mining Journal, Oct. 15TH. P. 246.South AfricaDiamond Occurrences
DS1910-0010
1910
Anon.Anon.Diamond Washing and CuttingChambers's Journal, Vol. 26, P. 219.South AfricaIndustry, Recovery
DS1910-0011
1910
Anon.Anon.South African Diamonds (1910)Engineering and Mining Journal, Vol. 89, Feb. 28TH. P.South AfricaKimberley Mines, Production
DS1910-0012
1910
Anon.Anon.Mr. Purdy's Diamond SchemeSouth Africa, Vol. 87, JULY 23RD. P. 215.South AfricaMineral Economics, Prices
DS1910-0013
1910
Anon.Anon.Salting a Growing Evil. the Case of the Diamond Mine - Unscientific Sampling.South African Mining Journal, Vol. 8, PT. 1, JUNE 18TH. P. 455.South AfricaSampling, Hoax
DS1910-0014
1910
Anon.Anon.Searching for New Diamond Fields. Expedition Departs for The Interior of South Africa in Search of Precious Stones.Butte Montana News, Jan. 16TH.South Africa, BotswanaCurrent Activities, Travelogue, History
DS1910-0015
1910
Anon.Anon.Premier Diamonds: the Mine's History in BriefSouth African Mining Journal, Vol. 8, PT. 1, MARCH 12TH. No. 366, P. 42.South Africa, Kimberley AreaPremier, Mine, Mining Economics
DS1910-0016
1910
Anon.Anon.Mining Accidents on the River DiggingsSouth African Mining Journal, Vol. 8, PT. 1, JUNE 11TH. P. 422.South Africa, Klipdam, Barkly WestMining Recovery
DS1910-0017
1910
Anon.Anon.Vaal River Diamonds: Some New ProjectsSouth African Mining Journal, Vol. 8, PT. 1, MAR. 18TH. P. 52.South Africa, Vaal RiverAlluvial Diamond Placers
DS1910-0018
1910
Anon.Anon.The River Diggings (1910)South African Mining Journal, Vol. 8, PT. 2, Oct. 8TH. P. 183.South Africa, Vaal RiverMining Engineering
DS1910-0019
1910
Anon.Anon.The River Diggings (1910) #2South Africa, Vol. 87, SEPT. 24TH. P. 703.South Africa, Vaal RiverMining Engineering
DS1910-0020
1910
Anon.Anon.Diamonds; Kolonie Heimat, 1910Kolonie Heimat., Vol. 3-5, SEE CONTENTS.Southwest Africa, NamibiaCurrent Activities
DS1910-0021
1910
Anon.Anon.Diamonds of Southwest AfricaMinerals Yearbook For 1909, PP. 570-573.Southwest Africa, NamibiaDiamond Occurrence
DS1910-0022
1910
Anon.Anon.Gegen die Luderitzbuchter DiamantenBerlin: Dietrich Reimer., Southwest Africa, NamibiaDiamonds, Kimberley, Politics
DS1910-0023
1910
Anon.Anon.The Placer Diamond FieldsEngineering and Mining Journal, Vol. 89, Feb. 28TH. P.Southwest Africa, NamibiaLittoral Diamond Placers
DS1910-0024
1910
Anon.Anon.Mining in German Southwest AfricaEngineering and Mining Journal, Southwest Africa, NamibiaLittoral Diamond Placers
DS1910-0025
1910
Anon.Anon.German Southwest African Diamond Fields #2South African Mining Journal, Vol. 8, PT. 1, MAY 28TH. P. 373.Southwest Africa, NamibiaOccurrence
DS1910-0026
1910
Anon.Anon.Diamonds; Geological Society of South Africa, 1910Anniversary Address of The President of The Geological Society South, Vol. 13, PP. XXIV-XXV.Southwest Africa, Namibia, South AfricaAlluvial Diamond Placers, Littoral, Genesis
DS1910-0027
1910
Anon.Anon.Diamonds of California; 1910United States Geological Survey (USGS) MINERALS YEARBOOK, PP. 859-860.United States, California, West CoastDiamond Occurrence
DS1910-0028
1910
Anon.Anon.United States Diamond Mining Company (1910)Engineering and Mining Journal, Vol. 89, APRIL 2ND. P. 736.United States, California, West CoastBlank
DS1910-0029
1910
Anon.Anon.Interesting Facts, Diamonds and Diamond Mining; Comparison Of the South African Mines with the Mines of Pike County.Little Rock: Arkansaw Diamond Mining Company, 12 P.United States, Gulf Coast, Arkansas, PennsylvaniaProspectus
DS1910-0030
1910
Anon.Anon.Native Diamond FoundObserver (charlotte), Jan. 7TH.United States, North Carolina, AppalachiaBlank
DS1910-0115
1911
Anon.Anon.Diamonds in Australia, 1910The Mineral Industry During 1910, Vol. 19, P. 573.Australia, VictoriaReview Of Current Activities
DS1910-0116
1911
Anon.Anon.Brasil: Diamond Bearing DepositsMining and Scientific Press, APRIL 1ST. P. 473.BrazilGeology
DS1910-0117
1911
Anon.Anon.Diamonds in British Columbia; August, 1911Engineering and Mining Journal, Vol. 92, AUGUST 26TH. P. 416.Canada, British ColumbiaProspecting
DS1910-0118
1911
Anon.Anon.Brief Note by C. Camsell Included in Report... on Diamonds In Chromium Ore of Olivine Mountain.Mineral Resources of The United States For 1910, PT. 2, PP. 860-861.Canada, British ColumbiaBlank
DS1910-0119
1911
Anon.Anon.Discusses Diamonds Found in Chromite Olivine Mountain in Tulameen River Area.The Mineral Industry During 1910, Vol. 19, PP. 575-578.Canada, British ColumbiaBlank
DS1910-0120
1911
Anon.Anon.Diamond Indications in British ColumbiaCan. Engineering, Vol. 20, MARCH 30TH. PP. 504-505.Canada, British ColumbiaBlank
DS1910-0121
1911
Anon.Anon.Diamond in British ColumbiaEngineering and Mining Journal, Vol. 91, MARCH 25TH. P. 632.Canada, British ColumbiaBlank
DS1910-0122
1911
Anon.Anon.Diamonds in QuebecEngineering and Mining Journal, Vol. 91, JUNE 17TH. P. 1224.Canada, QuebecBlank
DS1910-0123
1911
Anon.Anon.The Mineral Resources of the KatangaSouth African Mining Journal, AUGUST 12TH. P. 976Democratic Republic of CongoDiamonds
DS1910-0124
1911
Anon.Anon.Pruefunf von DiamantenZeitschr. F. Prakt. Geol., Vol. 19 PP. 395-396.GlobalGemology
DS1910-0125
1911
Anon.Anon.Lindgren, WThe Teriary Gravels of The Sierra Nevada of California., United States Geological Survey (USGS) PROF. PAPER.GlobalBlank
DS1910-0126
1911
Anon.Anon.Montrose DiamondsSouth African Mining Journal, Vol. 9, PT. 2, Oct. 14TH. P. 172.South AfricaCompany Report
DS1910-0127
1911
Anon.Anon.Notes on the South African Diamond MinesJewellers Circular Keystone, Vol. 60, No. 15, MAY 11TH. P. 114.South AfricaCurrent Activities
DS1910-0128
1911
Anon.Anon.Mining in Cape ColonySouth African Mining Journal, Vol. 9, PT. 2, Dec. 2ND.and 16TH. P. 455; P. 533.South AfricaCurrent Activities
DS1910-0129
1911
Anon.Anon.Column Report: National Diamonds; New Vaal River Diamond And Exploration Company.South African Mining Journal, Vol. 9, PT. 2, Oct. 7TH. No. 448, P. 137.South AfricaCurrent Activities
DS1910-0130
1911
Anon.Anon.Alluvial Diamonds and Digging ConditionsSouth African Mining Journal, Vol. 9, PT. 1, JULY 29TH. No. 438, P. 896.South AfricaCurrent Activities, History, Bloemhof
DS1910-0131
1911
Anon.Anon.Mooifontein Alluvial Diggings. the Cost of Supplies-facilities for the Unprovided- the Eternal Labour Problem- Health And Climatic Conditions-the New Diggers Prospects and Difficulties.South African Mining Journal, Vol. 9, PT. 2, Oct. 7TH. P. 143.South AfricaLaws, Diggings
DS1910-0132
1911
Anon.Anon.Mooifontein Alluvial Diggings. the Cost of Supplies-facilitiSouth African Mining Journal, Vol. 9, PT. 2, Dec. 9TH. P. 488. ALSO: Jan. 20TH. 1912.South AfricaLaws, Politics, Current Activities
DS1910-0133
1911
Anon.Anon.The Bloemhof Diamond DiggingsSouth African Mining Journal, Vol. 9, PT. 2, Dec. 23RD. PP. 563-566.South AfricaMap, Current Activities
DS1910-0134
1911
Anon.Anon.The Monastery Diamond Mine Resuscitated. Rand Syndicate Interested. Another Trial - Past History of the Property. Also Deep Level Working on the River Diggings.South African Mining Journal, Vol. 9, PT. 1, JULY 15TH. P. 814.South AfricaMining Methods
DS1910-0135
1911
Anon.Anon.The Kimberley and Rand Systems Compared. Rand Engineers Criticise Paper by Alpheus Williams.South African Mining Journal, Vol. 9, PT. 1, MAY 27TH. PP. 553-554.South AfricaMining Methods
DS1910-0136
1911
Anon.Anon.Petrography of the Premier KimberliteSouth African Mining Journal, Vol. 9, PT. 1, JULY 15TH.; 22ND.; 29TH.South AfricaPetrography
DS1910-0137
1911
Anon.Anon.Profung von DiamantenZeitschr. F. Prakt. Geol., NOVEMBER PP. 395-396.South AfricaProspecting
DS1910-0138
1911
Anon.Anon.Column Report: Koffyfontein Diamonds; Wedburg DiggingsSouth African Mining Journal, Vol. 9, PT. 2, Dec. 9TH. P. 488.South AfricaProspecting
DS1910-0139
1911
Anon.Anon.The Kimberley System of Handling GroundSouth African Mining Journal, Vol. 9, PT. 1, APRIL 29TH. P. 409.South Africa, Kimberley AreaMining Methods
DS1910-0140
1911
Anon.Anon.Mining in the Cape Colony. Review of the Year at Alluvial Diggings.South African Mining Journal, Vol. 9, PT. 2, Dec. 2ND. P. 455.South Africa, Kimberley AreaProspecting, Production
DS1910-0141
1911
Anon.Anon.The Diamond Mines of the Orange Free StateSouth African Mining Journal, Vol. 9, PT. 1, JULY 29TH. No. 438, P. 900.South Africa, Orange Free StateCurrent Activities
DS1910-0142
1911
Anon.Anon.The Chemical Composition of the BluegroundSouth African Mining Journal, Vol. 9, PT. 1, JULY 15TH. P. 820. ALSO JULY 22ND. P. 858.South Africa, PremierPremier, Analyses
DS1910-0143
1911
Anon.Anon.Dredging on the VaalSouth African Mining Journal, Vol. 9, PT. 1, JULY 1ST. P. 726A.South Africa, Vaal RiverHistory
DS1910-0144
1911
Anon.Anon.Mining in the Outside Districts. a Diamond DiscoverySouth African Mining Journal, Vol. 9, PT. 2, Oct. 28TH. P. 255.South Africa, Vaal RiverProspecting
DS1910-0145
1911
Anon.Anon.The Coastal Diamond Deposits of German Southwest Africa. The Probable Origin of the Diamonds and Alleged Cretaceous Gravels Along the Coast. Processes of Concentration.South African Mining Journal, Vol. 9, PT. 2, SEPT. 16TH. P. 56.Southwest Africa, NamibiaGeology, Littoral Diamond Placers
DS1910-0146
1911
Anon.Anon.Germany's African Diamond FieldsEngineering and Mining Journal, Vol. 92, SEPT. 23RD. P. 595.Southwest Africa, NamibiaLittoral Diamond Placers
DS1910-0147
1911
Anon.Anon.German Diamond RegieSouth African Mining Journal, Vol. 9, PT. 2, Oct. 14TH. P. 180.Southwest Africa, NamibiaPolitics
DS1910-0148
1911
Anon.Anon.German Southwest African DiamondsSouth African Mining Journal, Vol. 9, PT. 2, SEPT. 16TH. PP. 38-39.Southwest Africa, Namibia, JerusalemProspecting, Diamond Occurrence, Littoral Diamond Placers
DS1910-0149
1911
Anon.Anon.Mining in the Cape Colony 11. Review of a Year in the Outside Districts And small Mines- Results of Prospecting the Islands.South African Mining Journal, Vol. 9, PT. 2, Dec. 16TH. P. 533.Southwest Africa, Namibia, PeruProspecting, Littoral Diamond Placers
DS1910-0150
1911
Anon.Anon.Mechanical Devices for Diamond DepositsMining and Scientific Press, Vol. 102, Jan. 14TH. PP. 113-114.United StatesMining Engineering
DS1910-0151
1911
Anon.Anon.California Diamonds, 1911Mining Science, Vol. 64, Nov. 23RD. P. 473.United States, California, West CoastBlank
DS1910-0152
1911
Anon.Anon.Diamonds; Engineering and Mining Journal, 1911Engineering and Mining Journal, Vol. 91, Feb. 11TH. P. 340.United States, California, West CoastBlank
DS1910-0153
1911
Anon.Anon.Diamonds in Union County, GeorgiaJewellers Circular Keystone, Vol. 62, No. 21, JUNE 21, P. 91.United States, Georgia, AppalachiaBlank
DS1910-0154
1911
Anon.Anon.Found Diamonds 35 Years Ago. Washington Telegraph Publishes extract from the Gazette Telling of Discovery of First Gem.Little Rock Gazette., SEPT. 10TH.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS1910-0155
1911
Anon.Anon.Further Details of the Discovery of the Large Diamond at Pike County, Arkansaw.Jewellers Circular Keystone, Vol. 62, No. 22, JUNE 28TH, P. 57.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS1910-0156
1911
Anon.Anon.Diamonds in TexasMining Engineering WORLD., Vol. 35, AUGUST 12TH. P. 278.United States, Texas, Gulf CoastBlank
DS1910-0157
1911
Anon.Anon.Precious Stones in Texas (1911)Engineering and Mining Journal, Vol. 91, Jan. 28TH. P. 219.United States, Texas, Gulf CoastBlank
DS1910-0158
1911
Anon.Anon.Diamond Dykes in WyomingManufacturer Jewellers, Vol. 49, SEPT. 21ST. P. 598.United States, Wyoming, Rocky MountainsBlank
DS1910-0159
1911
Anon.Anon.Diamonds in Liberia. 1911South African Mining Journal, AUGUST 12TH. P. 1003.West Africa, LiberiaDiamond Occurrences
DS1910-0232
1912
Anon.Anon.Diamond Find in Keewatin DistrictWinnipeg Free Press, Jan. 10TH.Canada, OntarioBlank
DS1910-0233
1912
Anon.Anon.Diamond in Hudson Bay RegionEngineering and Mining Journal, Vol. 92, MAY 25TH. P. 1052; JUNE 15TH. P. 1202.Canada, Ontario, James Bay LowlandsBlank
DS1910-0234
1912
Anon.Anon.Diamond Near James BayEngineering and Mining Journal, Vol. 94, SEPT. 21. P. 564.Canada, Ontario, James Bay LowlandsBlank
DS1910-0235
1912
Anon.Anon.Diamond Find in Ungava Unlikely to Be Producer. Prospector Mislead through Frequency of Blue Clay Areas in Northern Quebec.Montreal Star., Oct. 5TH.Canada, Quebec, LabradorBlank
DS1910-0236
1912
Anon.Anon.Recueil Mensuel des Proces Verbaux des Seances de la Chambre Syndicale des Negociants En Diamants, Perles, Pierres Precieuses et des Lapidaires.Paris: Siege De la Chambre., No. 1GlobalBlank
DS1910-0237
1912
Anon.Anon.Frank Smith Diamond Establishes an Exploration CompanySouth African Mining Journal 21ST. ANNIVERSARY VOLUME., SEPTEMBER, P. 426.South AfricaCurrent Activities
DS1910-0238
1912
Anon.Anon.The Diamond Diggings 1912South African Mining Journal, Vol. 22, PT. 1, SEPT. 28TH. P. 105.South AfricaCurrent Activities
DS1910-0239
1912
Anon.Anon.Diamonds and Fact. Criticism of Premier D.m.cSouth African Mining Journal, Vol. 9, PT. 2, Feb. 24TH. P. 889.South AfricaCurrent Activities
DS1910-0240
1912
Anon.Anon.New Diamond Discoveries (1912)South African Mining Journal, Vol. 10, PT. 1, No. 487, JULY 6TH. PP. 689-690.South AfricaDiamond Occurrences
DS1910-0241
1912
Anon.Anon.A Stone of 1649 Carats Found at Premier. Since Culli nan This Is the Largest.Cape Argus, Nov. 6TH.South AfricaHistory, Diamonds Notable
DS1910-0242
1912
Anon.Anon.The River Diggers' Average.South African Mining Journal, Vol. 10, PT. 1, MAY 11TH. P. 386.South AfricaHistory, Politics
DS1910-0243
1912
Anon.Anon.Diamond Occurrences in Pretoria DistrictSouth African Mining Journal, Vol. 10, PT. 1, AUGUST 3RD. PP. 847-850.South AfricaKimberlite Occurrences, Genesis, Geology
DS1910-0244
1912
Anon.Anon.Abolishing the Diamond BuyerSouth Africa, Vol. 94, JUNE 15TH. P. 607.South AfricaMineral Economics, Prices
DS1910-0245
1912
Anon.Anon.New Rotary WasherSouth African Mining Journal, Vol. 9, PT. 2, Feb. 10TH. P. 845.South AfricaMining Methods, Diamond Recovery
DS1910-0246
1912
Anon.Anon.Great Interest in Discovery of a Big Fissure, Containing Yellow Diamondiferous Soil Outside of Barkly West.Cape Argus, SEPT. 19TH.South AfricaProspecting
DS1910-0247
1912
Anon.Anon.How Some Districts Are Discovered by AccidentMining Eng. World., Vol. 36, No. 11, MARCH 16TH. PP. 591-592.South Africa, BrazilProspecting
DS1910-0248
1912
Anon.Anon.How Diamonds Are Dug from the Kimberley MinesJewellers Circular Keystone, Vol. 34, P. 1821.South Africa, Cape ProvinceMining Methods
DS1910-0249
1912
Anon.Anon.Perils of Diamond PitsJewellers Circular Keystone, Vol. 64, No. 18, Jan. 5TH. P. 57.South Africa, Cape ProvinceMining Methods
DS1910-0250
1912
Anon.Anon.The Derdepoort Geological Problem. Volcanic Breccia or Kimberlite, Insufficient Evidence of Peridotite, Further Information Desireable.South African Mining Journal, Vol. 10, PT. 1, JULY 27TH. No. 490, P. 805. The Mining Journal, OCSouth Africa, TransvaalAlkaline Rocks, Related Rocks
DS1910-0251
1912
Anon.Anon.The Geological Problem at Derdepoort. a Petrological Puzzle, No Reliable Solution Offered, a Pipe More Than a Square Mile in Area.Mining Engineering Journal of South Africa, Vol. 10, PT. 1, AUGUST 24TH. No. 494, P. 950.South Africa, TransvaalAlkaline, Related Rocks
DS1910-0252
1912
Anon.Anon.Future Mining Methods at the PremierSouth African Mining Journal, Vol. 22, PT. 1, Dec. 14TH. PP. 472-473.South Africa, TransvaalMining Methods, Premier
DS1910-0253
1912
Anon.Anon.Diamonds; 1912South African Mining Journal 21ST. ANNIVERSARY VOLUME., SEPTEMBER, P. 297.South Africa, ZimbabwePolitics, Laws
DS1910-0254
1912
Anon.Anon.Les Diamants Au Sud Ouest Africain AllemandMouv. Geogr., P. 119.Southwest Africa, NamibiaDiamonds, Occurrences
DS1910-0255
1912
Anon.Anon.Diamonds in German Southwest Africa, 1912Engineering and Mining Journal, Vol. 94, No. 1, P. 10.Southwest Africa, NamibiaLittoral Diamond Placers, Production
DS1910-0256
1912
Anon.Anon.Diamonds in California, 1912Engineering and Mining Journal, Vol. 94, SEPT. 7TH. P. 469.United States, California, West CoastBlank
DS1910-0257
1912
Anon.Anon.Fine Flawless Diamond Reported to Have Been Found at Mine Near murfreesboro, Arkansaw.Jewellers Circular Keystone, Vol. 64, No. 18, JUNE 5TH. P. 67.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS1910-0258
1912
Anon.Anon.Diamonds Found in TexasUnited States Geological Survey (USGS) MINERALS YEARBOOK, PP. 1040-1041.United States, Texas, Gulf CoastDiamond Occurrence
DS1910-0317
1913
Anon.Anon.Dredging Operations in BrasilMining and Scientific Press, Vol. 106, JUNE 28TH. P. 980.BrazilMining Engineering
DS1910-0318
1913
Anon.Anon.Diamonds of the Congo; 1912The Mineral Industry During 1912, Vol. 22, PP. 639-640.Democratic Republic of Congo, Central AfricaBlank
DS1910-0319
1913
Anon.Anon.Vaal River ProspectsSouth African Mining Journal, Vol. 22, PT. 2, Apr. 26TH. P. 209.South AfricaAlluvial Diamond Placers
DS1910-0320
1913
Anon.Anon.Life at the River DiggingsSouth Africa, Vol. 99, SEPT. 27TH. PP. 655-656.South AfricaCurrent Events
DS1910-0321
1913
Anon.Anon.459 Carat Diamond Found at 260' Level in the PremierCape Argus, APRIL 17TH.South AfricaDiamonds Notable
DS1910-0322
1913
Anon.Anon.Diamonds Near the PilandsbergSouth African Mining Journal, Vol. 22, PT. 1, MAY 3RD. P. 240. ALSO: 1914 Vol. 23, PT. 1South AfricaOccurrence
DS1910-0323
1913
Anon.Anon.The Southwest Diamond Fields. Bloemhof-klerksdorp Alluvial diggings- How the Men are Faring-rate of Production Over Half a Million a Year- the Principal Finds.South African Mining Journal, Vol. 22, PT. 2, No. 1139, JULY 26TH. PP. 568-570.South AfricaOccurrence
DS1910-0324
1913
Anon.Anon.In Search of DiamondsPamphlet:, 28P.South AfricaProspecting, Kimberley
DS1910-0325
1913
Anon.Anon.The Diamond Bearing Alluvials of Schweizer ReneckeSouth African Mining Journal, Vol. 22, PT. 2, SEPT. 20TH. No. 1147, PP. 65-67.South Africa, TransvaalAlluvial Diamond Placers
DS1910-0326
1913
Anon.Anon.Diamonds in the BanketMining Engineering Journal of South Africa, Vol. 22, PT. 2, JUNE 14TH. No. 1133, P. 397.South Africa, TransvaalDiamonds Occurrence, Precambrian Conglomerate, Modderfontein
DS1910-0327
1913
Anon.Anon.Caisson DiggingSouth African Mining Journal, Vol. 22, PT. 1, Feb. 1ST. P. 704.South Africa, Vaal RiverMining Engineering
DS1910-0328
1913
Anon.Anon.German Southwest African Diamond MinesEngineering and Mining Journal, Vol. 96, No. 10, P. 456.Southwest Africa, NamibiaDiamond Mining
DS1910-0329
1913
Anon.Anon.German West African Diamond FieldsSouth African Mining Journal, Vol. 22, PT. 1, AUGUST 23RD. PP. 673-674.Southwest Africa, NamibiaOccurrence, Littoral Diamond Placers
DS1910-0330
1913
Anon.Anon.Diamonds in Plumas County, California, 1913Sacramento Union., AUGUST 17TH.United States, California, West CoastBlank
DS1910-0331
1913
Anon.Anon.U.s. Diamond Mining Company, OrovilleMining Engineering WORLD., Vol. 38, MARCH 8TH. P. 496.United States, California, West CoastBlank
DS1910-0332
1913
Anon.Anon.Diamonds in California, 1913Engineering and Mining Journal, Vol. 95, Jan. 18TH. P. 203.United States, California, West CoastBlank
DS1910-0333
1913
Anon.Anon.Diamonds in Arkansaw, 1913Engineering and Mining Journal, Vol. 96, No. 11, SEPT. 13TH. PP. 488-489.United States, Gulf Coast, Arkansas, PennsylvaniaDiamond Occurrence News Item
DS1910-0334
1913
Anon.Anon.Diamond Mining in the United States (us)South African Mining Journal, Vol. 22, PT. 1, Feb. 15TH. P. 761.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS1910-0335
1913
Anon.Anon.Kimberlite Company's Charter RevokedEngineering and Mining Journal, Vol. 96, Oct. 18TH. P. 751. Nov. 1, P. 855.United States, Gulf Coast, Arkansas, PennsylvaniaProspecting, Mining Economics, Trade, Law, News Item
DS1910-0393
1914
Anon.Anon.Diamonds in OntarioMining Engineering WORLD., Vol. 40, MAY 2ND. P. 856.Canada, OntarioBlank
DS1910-0394
1914
Anon.Anon.Diamond Mines of South Africa. #2Journal of GEOLOGY, Vol. 13, P.South AfricaGeology
DS1910-0395
1914
Anon.Anon.Outline of the Report by Dominion Royal Commission of Great britain on the Diamond Industry in the Union of South Africa.South African Mining Journal, Vol. 23, PT. 2, AUG. 8TH. PP. 601-603.South AfricaMining Economics, Politics
DS1910-0396
1914
Anon.Anon.The Diamond ConferenceMining Engineering Journal of South Africa, Vol. 23, PT. 2, P. 629.South AfricaMining Economics, Trade
DS1910-0397
1914
Anon.Anon.Progress in the Treatment of Diamondiferous Ground. Harrisdale Diamonds. Prospecting Work Along the Barkley Fissure.South African Mining Journal, Vol. 23, PT. 1, Feb. 14TH. PP. 562-563.South AfricaMining Engineering
DS1910-0398
1914
Anon.Anon.Modern Diamond PlantMining Engineering Journal of South Africa, Vol. 24, PT. 1, SEPT. 5TH. P. 5.South AfricaMining Engineering
DS1910-0399
1914
Anon.Anon.Setzmaschine Fur Diamant Fuehrenden SandGluckauf., JUNE 6TH.South AfricaMining Recovery
DS1910-0400
1914
Anon.Anon.Mining and Prospecting in the CapeSouth African Mining Journal, Vol. 23, PT. 1, Feb. 28TH. P. 625.South AfricaPolitics
DS1910-0401
1914
Anon.Anon.Colonial Diamond Mining CompanyEngineering and Mining Journal, Vol. 97, No. 16, APRIL 18TH. P. 825.Southwest Africa, NamibiaDiamond Mining Company, Dividend
DS1910-0402
1914
Anon.Anon.Satzung. Diamanten regie des Suedwest afrikanischen Schutzgebiets.Berlin: Liebheit U Theisen., 37P.Southwest Africa, NamibiaMining Law, Kimberley
DS1910-0403
1914
Anon.Anon.Diamonds of California; 1914United States Geological Survey (USGS) MINERALS YEARBOOK FOR 1914, P.320.United States, California, West CoastDiamond Occurrence
DS1910-0404
1914
Anon.Anon.Diamonds in California, 1914Engineering and Mining Journal, Vol. 98, JULY 25TH. P. 186.United States, California, West Coast, El DoradoBlank
DS1910-0405
1914
Anon.Anon.California, 1913Mineral Resources of The United States For 1913, PT. 2, PP. 663-666.United States, California, West Coast, Plumes, Montana, Idaho, Rocky MountainsBlank
DS1910-0449
1915
Anon.Anon.Diamonds from ChinaSouth African Mining Journal, Vol. 24, PT. 2, No. 1254, Oct. 9TH. PP. 125-126.ChinaDiamond Occurrences
DS1910-0450
1915
Anon.Anon.Mines of ShantungFar East Review Magazine, MARCH PP. 402-405.ChinaDiamonds
DS1910-0451
1915
Anon.Anon.The Diamond ProhibitionSouth Africa, Vol. 107, AUG. 7TH. P. 204.South Africa, GlobalMining Economics, Politics
DS1910-0452
1915
Anon.Anon.The Economic Resources of German Southwest AfricaImp. Institute Bulletin., APRIL- JUNE, 27P.Southwest Africa, NamibiaDiamonds, Occurrences, Mineral Resources, Economics
DS1910-0453
1915
Anon.Anon.Uncut Diamonds Brought from Southwest AfricaEngineering and Mining Journal, Vol. 100, No. 5, P. 200.Southwest Africa, NamibiaIdb
DS1910-0454
1915
Anon.Anon.The Union's Newest Diamond MineMining Engineering Journal of South Africa, Vol. 24, PT. 1, No. 1222, P. 497.Southwest Africa, Namibia, LuderitzbuchtGeology, Mining Engineering
DS1910-0455
1915
Anon.Anon.Remarkable Occurrences of DiamondsJewellers Circular Keystone, SEPT. 1ST. P. 55.United States, Arizona, Colorado PlateauDiamond Genesis, Canyon Diablo, Meteorite
DS1910-0456
1915
Anon.Anon.Diamond in MontanaThe Mineral Industry During 1914, Vol. 23, P. 648.United States, Montana, Rocky MountainsBlank
DS1910-0457
1915
Anon.Anon.Diamonds of RhodesiaThe Mineral Industry During 1914, Vol. 24, PP. 605-606.ZimbabweBlank
DS1910-0483
1916
Anon.Anon.Hints on Judging DiamondsScientific American Suppl., Feb. 26TH. P. 133.GlobalDiamond Morphology
DS1910-0484
1916
Anon.Anon.Gold and Diamond Mining in the Klerksdorp DistrictSouth African Mining Journal, Vol. 24, PT. 1, Jan. 22ND. P. 489.South AfricaCurrent Activities
DS1910-0485
1916
Anon.Anon.The Genesis of the Diamond (1916)Jewellers Circular Keystone, Vol. 73, No. 12, Oct. 18TH. P. 51.South AfricaDiamond Genesis
DS1910-0486
1916
Anon.Anon.Vaal River Bed CaseSouth African Mining Journal, Vol. 24, PT. 2, Oct. 14TH. P. 152.South AfricaHistory
DS1910-0487
1916
Anon.Anon.De Beers and the Diamond OutlookSouth African Mining Journal, Vol. 24, PT. 1, Jan. 1ST. PP. 409-410.South AfricaInvestment
DS1910-0488
1916
Anon.Anon.Diamonds at Aliwal NorthCape Argus, SEPT. 16TH.South AfricaProspecting
DS1910-0489
1916
Anon.Anon.Some Remarkably Good Finds of Diamonds on Klipdam and the Bed of the Vaal River Near Barkly West.Cape Argus, SEPT. 20TH.South AfricaProspecting
DS1910-0490
1916
Anon.Anon.Diamond Mining in Southwest Africa. #1Mining Engineering Journal of South Africa, APRIL PP. 67-68.Southwest Africa, NamibiaCurrent Activities
DS1910-0491
1916
Anon.Anon.Diamonds; Mining and Scientific Press, 1916Mining and Scientific Press, Vol. 113, JULY 8, P. 65.United States, California, West CoastBlank
DS1910-0492
1916
Anon.Anon.Hidden Diamond Mine Is Sought by ProspectorsSan Francisco Chronicle., Nov. 26TH.United States, California, West Coast, El DoradoBlank
DS1910-0493
1916
Anon.Anon.Precious Stones in 1915Engineering and Mining Journal, Vol. 102, No. 18, P. 800.United States, Gulf Coast, Arkansas, Pennsylvania, Brazil, South AfricaDiamond Occurrence
DS1910-0517
1917
Anon.Anon.Diamonds of the Congo; 1916The Mineral Industry During 1916, Vol. 26, P. 595.Democratic Republic of Congo, Central AfricaBlank
DS1910-0518
1917
Anon.Anon.Alewal North Diamond RushSouth African Mining Journal, Vol. 26, PT. 1, MARCH 3RD., P. 4.South AfricaCurrent Activities
DS1910-0519
1917
Anon.Anon.Diggers and Alleged ProfiteeringSouth African Mining Journal, Vol. 27, PT. 1, Oct. 20TH. P. 158.South AfricaMineral Economics
DS1910-0520
1917
Anon.Anon.California Diamonds, 1917The San Francisco Call Database, MARCH 11TH.United States, California, West CoastBlank
DS1910-0521
1917
Anon.Anon.California, 1916The Mineral Industry During 1916, Vol. 25, P. 628.United States, California, West CoastBlank
DS1910-0522
1917
Anon.Anon.Sterling Diamond ExcitementTexas Miner. Res., Vol. 1, No. 12, OCTOBER P. 26.United States, Texas, Gulf CoastBlank
DS1910-0551
1918
Anon.Anon.Diamond QuestionsUnknown., MARCH 2ND. P. 605.South AfricaGenesis, Origin
DS1910-0552
1918
Anon.Anon.De Beers and the Diamond IndustrySouth African Mining Journal, Vol. 28, PT. 1, Dec. 21ST. P. 335.South AfricaInvestment, Economics
DS1910-0553
1918
Anon.Anon.Vaal River Diggers Union Annual ReportSouth African Mining Journal, Vol. 28, PT. 1, Dec. 21ST. P. 343.South AfricaMining Engineering, Economics
DS1910-0563
1919
Anon.Anon.Diamonds of Gold CoastMinerals Yearbook For 1918, PP. 175-176.Ghana, West AfricaBlank
DS1910-0564
1919
Anon.Anon.Diamond, 1918The Mineral Industry During 1918, Vol. 28, PP. 605-607.Kenya, Gold Coast, Ghana, West AfricaBlank
DS1910-0565
1919
Anon.Anon.Diamond Mines in South Africa. #2Engineering and Mining Journal, Vol. 108, JULY 26TH. PP. 142-143.South AfricaCurrent Activities
DS1910-0566
1919
Anon.Anon.Crown DiamondsSouth African Mining Journal, Vol. 29, PT. 1, Dec. 20TH. P. 329.South AfricaCurrent Activities
DS1910-0567
1919
Anon.Anon.Caisson Aluvial Diamond Recovery. Cox's InventionSouth African Mining Journal, Vol. 28, PT. 2, SEPT. 6TH. P. 733. ALSO: Engineering and Mining Journal, NOSouth AfricaDiamond Mining Recovery
DS1910-0568
1919
Anon.Anon.Big Diamond 388 1/2 Carats from the Jagersfontein MineCape Argus, Jan. 13TH.South AfricaDiamonds Notable
DS1910-0569
1919
Anon.Anon.Diamond Taxation and Diamond CuttingSouth African Mining Journal, Vol. 28, PT. 2, MARCH 8TH. P. 3.South AfricaLaws
DS1910-0570
1919
Anon.Anon.Boom in DiamondsSouth African Mining Journal, Vol. 28, PT. 2, JULY 26TH. P. 589.South AfricaMarkets, Production, Prices
DS1910-0571
1919
Anon.Anon.The Lesser Ore ConcentratorSouth African Mining Journal, Vol. 28, PT. 2, MAY 3RD. P. 261.South AfricaMining Engineering
DS1910-0572
1919
Anon.Anon.Caisson Alluvial Diamond Recovery. #2Sth. Afr. Min. . Journal, Vol. 28, PT. 2, SEPT. 6TH. P. 733.South AfricaMining Engineering
DS1910-0573
1919
Anon.Anon.The Late Sir William CrookesSouth African Mining Journal, Vol. 28, PT. 2, APRIL 19TH. P. 201.South AfricaObituary Notice
DS1910-0574
1919
Anon.Anon.Stinie DiamondsSouth African Mining Journal, Vol. 29, PT. 1, Dec. 27TH. No. 1474, PP. 345-346.South Africa, TransvaalAlluvial Diamond Placers
DS1910-0575
1919
Anon.Anon.Diamond Mining by Diving BellMining and Scientific Press, Vol. 119, Dec. 6TH. P. 822.South Africa, Vaal RiverMining Engineering
DS1910-0576
1919
Anon.Anon.The Consolidated Diamond Mines of Southwest Africa 1919Mining Engineering Journal of South Africa, Vol. 45, PT. 1, No. 2171, P. 13.Southwest Africa, NamibiaCompany History, Geology
DS1910-0577
1919
Anon.Anon.New Outlook for Southwest DiamondsMining Engineering Journal of South Africa, Vol. 28, PT. 2, No. 1452, JULY 26TH. P. 597.Southwest Africa, NamibiaCurrent Activities
DS1910-0578
1919
Anon.Anon.The Latest Development of Diamond Mining in Southwest AfricMining Engineering Journal of South Africa, Vol. 29, PT. 1, Dec. 27TH. No. 1474, PP. 495-496.Southwest Africa, NamibiaGeology, Littoral Diamond Placers
DS1910-0579
1919
Anon.Anon.Releasing Soldiers Will Augment Number of Prospectors and Thereby Increase the Discovery of Gems.Jewellers Circular Keystone, Vol. 77, No. 24, Jan. 15TH. P. 50.United StatesBlank
DS1920-0001
1920
Anon.Anon.Diamonds in Mexico, 1920U.s. Commerce Reports, No. 274, No.V 20TH. P. 827.MexicoBlank
DS1920-0002
1920
Anon.Anon.Latest News from the Diamond Mines and FieldsVsth. Afr. Min. Journal, JULY 10TH. P. 450.South AfricaCurrent Activities
DS1920-0003
1920
Anon.Anon.Diamonds in the Desert: TaungsSouth African Mining Journal, MARCH 20TH. P. 61.South AfricaCurrent Activities
DS1920-0004
1920
Anon.Anon.The Postmasburg Diamond FieldMining Engineering Journal of South Africa, South African Mining Journal, Vol. 29, PT. 1, APRIL 17TH. No. 1490, P. 151.South AfricaCurrent Activities
DS1920-0005
1920
Anon.Anon.News from the Diamond FieldsMining Engineering Journal of South Africa, Vol. 29, PT. 1, Jan. 31ST. PP. 467-468.South AfricaCurrent Activities
DS1920-0006
1920
Anon.Anon.The Rich Rouxville Diamond DepositMining Engineering Journal of South Africa, Vol. 30, PT. 1, Oct. 9TH. No. 1515, P. 97.South AfricaCurrent Activities
DS1920-0007
1920
Anon.Anon.Splendid Prospects for the New Makganyene Diamond MinesMining Engineering Journal of South Africa, Vol. 30, PT. 1, OCTOBER 9TH. No. 1515, P. 101. Nov. 8TH. P.South AfricaCurrent Activities
DS1920-0008
1920
Anon.Anon.The Diamond BoomletSouth African Mining Journal, MARCH 13TH P. 25.South AfricaInvestment, Economics
DS1920-0009
1920
Anon.Anon.Prospecting in the Southwest ProtectorateSouth African Mining Journal, Jan. 3RD. P. 373.South AfricaLaws
DS1920-0010
1920
Anon.Anon.Project to Stop Diamond Rushes. Board of Controls SchemeSouth African Mining Journal, SEPT. 4TH. P. 692.South AfricaLaws
DS1920-0011
1920
Anon.Anon.The Position of the Diamond IndustryMining Engineering Journal of South Africa, Vol. 30, PT. 1, Dec. 11TH. No. 1572, PP. 359-361.South AfricaMining Economics
DS1920-0012
1920
Anon.Anon.Vaal River Diggers Union ActivitiesMining Engineering Journal of South Africa, Vol. 30, PT. 1, Nov. 27TH. P. 305.South AfricaMining Engineering
DS1920-0013
1920
Anon.Anon.Outlook for Postams Diamond ProspectSouth African Mining Journal, Feb. 28TH. PP. 571-572.South AfricaProspecting
DS1920-0014
1920
Anon.Anon.Diamond Prices and the ExchangeMining Engineering Journal of South Africa, Vol. 29, PT. 2, MAY 22ND. P. 272.South Africa, GlobalMining Economics, Prices
DS1920-0015
1920
Anon.Anon.Victory Diamonds Limited: Important AcquisitionsMining Engineering Journal of South Africa, Vol. 29, PT. 1, MARCH 20TH. No. 1486, P. 51.South Africa, Gordonia, Orange Free StateCurrent Activities
DS1920-0016
1920
Anon.Anon.Emerald Diamonds LtdMining Engineering Journal of South Africa, Vol. 29, PT. 1, Dec. 20TH. No. 1493, PP. 329-343.South Africa, Griqualand WestAlluvial Diamond Placers, Geology
DS1920-0017
1920
Anon.Anon.The Postmasburg Diamond FieldsMining Engineering Journal of South Africa, Vol. 29, PT. 1, APRIL 10TH. No. 1489, PP. 125-126.South Africa, Griqualand WestKimberlite Mines And Pipes, Current Activities
DS1920-0018
1920
Anon.Anon.Diamonds in the Desert. a Pegging Scramble -the Coming Rush near Taungs.Mining Engineering Journal of South Africa, Vol. 29, PT. 2, MARCH 20TH. No. 1486, P. 61.South Africa, Hartz RiverCurrent Activities, Prospecting
DS1920-0019
1920
Anon.Anon.Favourable Report on Stinies DiamondsMining Engineering Journal of South Africa, Vol. 30, PT. 1, No. 1517, PP. 157-158.South Africa, Transvaal, LichtenburgAlluvial Diamond Placers, Geology, Morphology, Diamonds
DS1920-0020
1920
Anon.Anon.The Alluvial DiggingsMining Engineering Journal of South Africa, Vol. 29, PT. 2, MARCH 6TH. PP. 2-3.South Africa, Vaal RiverCurrent Activities, Mineral Economics
DS1920-0021
1920
Anon.Anon.Recovering Diamonds by Diving Bell With Air LockCompressed Air Magazine., Vol. 25, JUNE P. 9697.South Africa, Vaal RiverMining Engineering
DS1920-0022
1920
Anon.Anon.Diamond Mining in Southwest Africa. #2Mining and Scientific Press, Vol. 120, JUNE 26TH. P. 939.Southwest Africa, NamibiaCurrent Activities
DS1920-0023
1920
Anon.Anon.Mines and MINERALS of the southwest PROTECTORATE. Official Diamond RETURNSSouth African Mining Journal, JUNE 26TH. P. 416.Southwest Africa, NamibiaProduction
DS1920-0024
1920
Anon.Anon.California Diamonds, 1920San Francisco Chronicle., Feb. 12TH. ALSO: NEW YORK GLOBE, MAY 15TH.United States, California, West CoastBlank
DS1920-0055
1921
Anon.Anon.Congo Diamonds, 1921Mining Engineering Journal of South Africa, No. 1544, PP. 1047-1049.Democratic Republic of Congo, Central AfricaGeology
DS1920-0056
1921
Anon.Anon.Frank Smith DiamondsMining Engineering Journal of South Africa, Vol. 30, PT. 1, JANUARY 22ND. No. 1530, P. 532.South AfricaCurrent Activities
DS1920-0057
1921
Anon.Anon.Big Diamond Unearthed Near Barkly West 381 CaratsCape Argus, JUNE 3RD.South Africa, Gong GongDiamonds Notable
DS1920-0058
1921
Anon.Anon.Kimberley Open Mine AbandonedThe Mineral Industry During 1920, Vol. 30, P. 593.South Africa, Griqualand WestMining Engineering
DS1920-0095
1922
Anon.Anon.Diamond, 1921The Mineral Industry During 1921, Vol. 31, PP. 599-602.Angola, Zaire, Central AfricaDiamond
DS1920-0096
1922
Anon.Anon.Mining Engineers of NoteEngineering and Mining Journal, Vol. 114, Nov. 11TH. P. 858.South AfricaBiography, Mining Engineering
DS1920-0097
1922
Anon.Anon.Diamonds in Arkansaw; June, 1922Engineering and Mining Journal, Vol. 113, JUNE 10TH. P. 990.United States, Gulf Coast, ArkansasNews Item
DS1920-0098
1922
Anon.Anon.Diamond Mining Is a Flourishing Arkansaw IndustryCurrent Opinion., Vol. 73, DECEMBER PP. 788-789.United States, Gulf Coast, ArkansasNews Item
DS1920-0122
1923
Anon.Anon.The Angola Diamond FieldsMining Engineering Journal of South Africa, Vol. 33, PT. 2, No. 1638, Feb. 17TH. PP. 633-634.AngolaDiamond Occurrence, History, Lunda, Production, Mining Engineering
DS1920-0123
1923
Anon.Anon.The Angolan Diamond DealSth. Afr. Engineering And Mining Journal, Vol. 33, PT. 2, Feb. 3RD. P. 575.Angola, West AfricaDiamond Occurrence
DS1920-0124
1923
Anon.Anon.The Angolan Diamond Deal. Belgian Congo and KasaiMining Engineering Journal of South Africa, Vol. 33, PT. 2, No. 1634, PP. 515-517.Angola, Zaire, Central AfricaAlluvial Diamond Placers
DS1920-0125
1923
Anon.Anon.The Angolan Diamond Fields... KasaiMining Engineering Journal of South Africa, No. 1638, PP. 633-634.Democratic Republic of Congo, Angola, Central AfricaAlluvial Diamond Placers
DS1920-0126
1923
Anon.Anon.Diamonds in the CongoMining Engineering Journal of South Africa, Vol. 33, PT. 2, No. 1676, P. 175.Democratic Republic of Congo, Central AfricaKasai, Alluvial Diamond Placers
DS1920-0127
1923
Anon.Anon.Diamonds Near ErmeloMining Engineering Journal of South Africa, Vol. 33, PT. 2, No. 1634, P. 527.South AfricaCurrent Activities
DS1920-0128
1923
Anon.Anon.Special Diamond SupplementMining Engineering Journal of South Africa, Vol. 33, PT. 2, Jan. 20TH. No. 1634, PP. 513-532.South Africa, Angola, Zaire, Central AfricaAlluvial Diamond Placers, Review, History Of The Industry
DS1920-0129
1923
Anon.Anon.Orange River Alluvial DiggingsMining Engineering Journal of South Africa, Vol. 34, PT. 1, SEPT. 8TH, No. 1667, P. 776.South Africa, BrakfonteinAlluvial Diamond Placers
DS1920-0130
1923
Anon.Anon.The Union's Newest Diamond Field. the Postmasburg AreaMining Engineering Journal of South Africa, Vol. 33, PT. 2, Jan. 20TH. No. 1634, P. 529.South Africa, Cape ProvinceKimberlite Mines And Deposits, Makganyene Mine
DS1920-0131
1923
Anon.Anon.The World's Gems. Precious Stones and Their Distribution -predominance of South Africa. Origin of Diamonds- a Valuable Contribution to the Literature of Gem Stones.Mining Engineering Journal of South Africa, Vol. 33, PT. 2, No. 1634, PP. 531-532.South Africa, GlobalDiamonds, Localities, History
DS1920-0132
1923
Anon.Anon.The Larger Diamond Mine ProducersMining Engineering Journal of South Africa, Vol. 33, PT. 2, Jan. 20TH., PP. 521-522.South Africa, Kimberley AreaMining Economics
DS1920-0133
1923
Anon.Anon.New Diamond RushesMining Engineering Journal of South Africa, Vol. 33, PT. 2, Feb. 17TH. P. 635.South Africa, Orange Free StateCurrent Activities
DS1920-0134
1923
Anon.Anon.West End DiamondsMining Engineering Journal of South Africa, Vol. 34, PT. 1, MARCH 10TH. No. 1641, PP. 725-726.South Africa, Postmasburg AreaKimberlite Mines And Deposits, Postmasburg Area, Mining Engineering
DS1920-0135
1923
Anon.Anon.New Diamond Rushes. Kaalplaats, Orange Free State, Lichtenburg, Ventersdorp.Mining Engineering Journal of South Africa, Vol. 34, PT. 1, Feb. 17TH. No. 1638, P. 635.South Africa, TransvaalAlluvial Diamond Placers
DS1920-0136
1923
Anon.Anon.New South African Diamond DiggingsMining Engineering Journal of South Africa, Vol. 34, PT. 1, SEPT. 15, No. 1668, P. 803.South Africa, TransvaalAlluvial Diamond Placers, Current Activities
DS1920-0137
1923
Anon.Anon.New Alluvial Rushes. Kaalplaats, Lichtenburg, BeynestpoortMining Engineering Journal of South Africa, Vol. 33, PT. 2, Jan. 20TH. No. 1634, P. 523.South Africa, TransvaalAlluvial Diamond Placers, Kaalplaats
DS1920-0138
1923
Anon.Anon.The Sterkfontein Diamond DiggingsMining Engineering Journal of South Africa, Vol. 34, PT. 1, APRIL 25TH. No. 1648, PP. 152-153.South Africa, TransvaalAlluvial Diamond Placers, Morphology, Diamonds
DS1920-0139
1923
Anon.Anon.New Alluvial RushesMining Engineering Journal of South Africa, Vol. 33, PT. 2, Jan. 20TH. P. 523.South Africa, Vaal RiverCurrent Activities
DS1920-0140
1923
Anon.Anon.The Southwest African Diamond Industry. Revival of Activity in the Luderitz.Mining Engineering Journal of South Africa, Vol. 34, PT. 1, APRIL 7TH. No. 1645, PP. 63-64.Southwest Africa, NamibiaLittoral Diamond Placers, Kolmanskop
DS1920-0141
1923
Anon.Anon.Desert Diamonds. the Romance of the Luderitzbucht Fields- Operations and Prospects of the Consolidated Company.Mining Engineering Journal of South Africa, Vol. 34, PT. 1, APRIL 28TH. No. 1648, PP. 164-165.Southwest Africa, NamibiaLittoral Diamond Placers, Mining Engineering
DS1920-0142
1923
Anon.Anon.Southwest African DiamondsMining Engineering Journal of South Africa, Vol. 33, PT. 2, Jan. 20TH. No. 1634, PP. 525-527.Southwest Africa, Namibia, Kolmanskop, LuderitzbuchtGeology, Littoral Diamond Placers
DS1920-0143
1923
Anon.Anon.Review of S.h. Ball Paper Entitled the Geologic and Geographic Occurrence of Precious Stones.Mining Engineering Journal of South Africa, Vol. 33, PT. 2, Jan. 20TH. PP. 531-532. MAP.United StatesBlank
DS1920-0144
1923
Anon.Anon.Diamond Deposits Believed LikelyPerris Progress, MARCH 15TH.United States, California, West CoastBlank
DS1920-0145
1923
Anon.Anon.Diamonds in the United States; August, 1923Indian Engineering, Vol. 74, AUGUST 11TH. P. 75.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS1920-0146
1923
Anon.Anon.Diamonds from Arkansaw. #1Jewellers Circular Keystone, Vol. 86, No. 18, JUNE 6TH. P. 65.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS1920-0147
1923
Anon.Anon.Diamonds from Arkansaw. #2Engineering and Mining Journal, Vol. 115, JUNE 16TH, P. 1071.United States, Gulf Coast, Arkansas, PennsylvaniaBlank
DS1920-0175
1924
Anon.Anon.Diamond, 1923The Mineral Industry During 1923, Vol. 32, PP. 616-618.Angola, Zaire, Gold Coast, Ghana, Southwest Africa, NamibiaDiamond Occurrences
DS1920-0176
1924
Anon.Anon.Namaqua Diamonds #1Mining Engineering Journal of South Africa, Vol. 35, PT. 2, Oct. 25TH. No. 1726, P. 185.South AfricaAlluvial Diamond Placers, Mining Engineering, Methods
DS1920-0177
1924
Anon.Anon.Diamond FieldsSouth Africa, Vol. 141, Feb. 22ND. P. 349.South AfricaCurrent Activities, Alluvial Diamond Placers
DS1920-0178
1924
Anon.Anon.Digging for Diamonds in South Africa. a Few TipsBeaufort West Courier., JULY 9TH.South AfricaMining Engineering, Prospecting
DS1920-0179
1924
Anon.Anon.Orange River DiamondsMining Engineering Journal of South Africa, Vol. 35, PT. 2, Oct. 4TH. No. 1723, P. 98.South Africa, Orange Free StateCurrent Activities, Mineral Economics
DS1920-0180
1924
Anon.Anon.Directory of Arkansaw IndustriesArkansaw BUREAU of Mines, MANUFACTURERS AND AGRICULTURE., 174P.United States, Gulf Coast, ArkansasBlank
DS1920-0201
1925
Anon.Anon.Diamond, 1924Western Australia Department of Mines Chem. Branch Annual Report For 1924, P. 11.Australia, Western AustraliaDiamond, Nullagine
DS1920-0202
1925
Anon.Anon.Brief Note on Address by W.a. ParksMining Engineering Journal of South Africa, Vol. 36, PT. 1, AUG. 22ND. P. 694.Canada, OntarioBlank
DS1920-0203
1925
Anon.Anon.How Diamonds Were Discovered in the Belgian CongoEngineering and Mining Journal, Vol. 27, P. 43.Democratic Republic of Congo, Central AfricaHistory
DS1920-0204
1925
Anon.Anon.Hold Diamonds Come from ResinsBridgeport Connecticut Post., Jan. 10TH.GlobalDiamond Genesis
DS1920-0205
1925
Anon.Anon.The Diamond Diggings 1925Mining Engineering Journal of South Africa, Vol. 36, PT. 1, JULY 18TH. PP. 569-570.South AfricaCurrent Activities
DS1920-0206
1925
Anon.Anon.Diamonds from the Lower Orange River ValleyMining Engineering Journal of South Africa, Vol. 36, PT. 2, Oct. 10TH. P. 153.South AfricaCurrent Activities
DS1920-0207
1925
Anon.Anon.Electrical Prospecting for DiamondsMining Engineering Journal of South Africa, Vol. 36, PT. 1, JUNE 13TH. P. 442.South AfricaGeophysics, Kimberlite
DS1920-0208
1925
Anon.Anon.Diamonds on the Port Nolloth BeachMin. Ind. Magazine (johannesburg
 
 

You can return to the Top of this page


Copyright © 2024 Kaiser Research Online, All Rights Reserved