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 - R-Rh


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 - R-Rh
Posted/
Published
AuthorTitleSourceRegionKeywords
DS1990-1483
1990
R.Turek, A. Keller, R.uranium-lead (U-Pb) zircon ages of volcanism and plutonism in the Mishibishu Greenstone belt near Wawa.Canadian Journal of Earth Sciences, Vol. 27, pp. 649-56.OntarioGeochronology, Wawa area
DS1997-0210
1997
R.Conticelli, S., Francala, L., Manetti, P. Cioni, R.Petrology and geochemistry of the ultrapotassic rocks from the SabatiniJournal of Volcanology, Vol. 75, No. 1-2 Jan. pp. 107-136.ItalyUltrapotassic, Magma
DS1989-1248
1989
Raab, G.A.Raab, G.A., Enwall, R.E., Cole, W.H., Kuharic, C.A., Duggan, J.S.Fast analysis of heavy metals in contaminated soils using field -portable X-ray fluorescence technology and geostatisticsPreprint from Northwest Mining Association 95th. Annual Meeting held Dec., 19pGlobalGeostatistics, X-ray fluorescence Heavy metals
DS2002-1294
2002
Raab, M.J.Raab, M.J., Brown, R.W., Gallagherm K., Carter, A., Weber, K.Late Cretaceous reactivation of major crustal shear zones in northern Namibia: constraints from apatite fission track analysis.Tectonophysics, Vol. 349, No. 1-4, pp.75-92.NamibiaGeochronology, Tectonics
DS1983-0527
1983
Raab, P.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
DS1987-0600
1987
Raade, G.Raade, G.Davanite K2TiSi6O15 in the Smoky Butte (Montana) Lamproites.Discussion of X-ray powder dataAmerican Mineralogist, Vol. 72, pp. 1014-1015MontanaLamproite
DS1950-0421
1958
Raal, F.A.Raal, F.A.A New Absorption Band in Diamond and Its Likely CauseProceedings of THE PHYSICAL SOCIETY, Vol. 71, No. 461, PP. 846-847.GlobalDiamond Morphology
DS1960-1194
1969
Raal, F.A.Raal, F.A.De Beers Research Serves the Diamond IndustryJohannesburg: De Beers Mining Corporation Limited., 39P.South AfricaKimberlite
DS1988-0559
1988
Rabalais, J.W.Rabalais, J.W., Kasi, S.R.Process for the deposition of diamond filmsPatent: PCT International Appl. 88 10321 Al Dec. 29, 1988 77p, GlobalDiamond Application, Patent
DS1989-0883
1989
Rabalais, J.W.Lifshitz, Y., Kasi, S.R., Rabalais, J.W.Subplantation model for film growth from hypersthermal species-application to diamondPhys. Rev. L., Vol. 62, No. 11, March 13, pp. 1290-1293GlobalDiamond morphology
DS201212-0611
2012
Rabassa, J.Rutter, N., Coronato, A.,Helmens, K., Rabassa, J., Zarate, M.Glaciations in North and South America from the Miocene to the last glacial maximum.Springer, Book adUnited States, Canada, South AmericaGeomorphology
DS200612-1497
2006
Rabatho, J.Waanders, F., Rabatho, J.Recovery of heavy minerals by means of ferrosilicon dense medium separation material.Hyperfine Interactions, Vol. 161, 1-4, Feb. pp. 55-60.TechnologyDMS diamond recovery
DS200612-1498
2006
Rabatho, J.Waanders, F., Rabatho, J.Recovery of heavy minerals by means of ferrosilicon dense medium separation material.Hyperfine Interactions, Vol. 161, 1-4, Feb. pp. 55-60.TechnologyMining
DS200612-0903
2006
Rabbel, W.Meissner, R., Rabbel, W., Kern, H.Seismic lamination and anisotropy of the Lower Continental Crust.Tectonophysics, Vol. 416, 1-4, April 5, pp. 81-99.MantleGeophysics - seismics
DS200612-0904
2006
Rabbel, W.Meissner, R., Rabbel, W., Kern, H.Seismic lamination and anisotropy of the Lower Continental Crust.Tectonophysics, in pressMantle, Europe, GermanyGeophysics - seismics, crust mantle boundary
DS1991-1392
1991
Rabe, J.P.Rabe, J.P., Buchholz, S.Commensurability and mobility in two dimensional molecular patterns ongraphiteScience, Vol. 253, July 26, pp. 424-427GlobalMineralogy, Graphite
DS1995-0894
1995
Rabe, R.Jones, A.P., Taniguchi, T., Dobson, D., Rabe, R., MilledgeExperimental nucleation and growth of diamond from carbonate-graphitesystems.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 269-270.GlobalPetrology -experimental, Diamond nucleation
DS1975-0841
1978
Raber, E.Raber, E.Zircons from Diamond Bearing Kimberlites: Oxide Reactions, Fission Track dating and a Mineral Inclusion Study.Amherst: Msc. Thesis, University Massachusetts, GlobalGeochronology, Mineral Chemistry
DS1975-1189
1979
Raber, E.Raber, E., Haggerty, S.E.Zircon-oxide Reactions in Diamond Bearing KimberlitesProceedings of Second International Kimberlite Conference, Proceedings Vol. 1, PP. 229-240.South AfricaMineralogy
DS1983-0274
1983
Raber, E.Haggerty, S.E., Raber, E., Naeser, C.W.Fissure Track Dating of Kimberlitic ZirconsEarth Plan. Sci. Letters, Vol. 63, No. 1, PP. 41-50.South Africa, Botswana, Angola, Tanzania, Wyoming, State LineGeochronology, Kimberley Pool, Orapa, Val Do Queve, Koffiefontein
DS201902-0309
2019
Rabesandratana, T.Rabesandratana, T.Will the world embrace plan S, the radical proposal to mandate open access to science papers?Science,, Jan 3, 3p.Globalopen access papers

Abstract: How far will Plan S spread? Since the September 2018 launch of the Europe-backed program to mandate immediate open access (OA) to scientific literature, 16 funders in 13 countries have signed on. That's still far shy of Plan S's ambition: to convince the world's major research funders to require immediate OA to all published papers stemming from their grants. Whether it will reach that goal depends in part on details that remain to be settled, including a cap on the author charges that funders will pay for OA publication. But the plan has gained momentum: In December 2018, China stunned many by expressing strong support for Plan S. This month, a national funding agency in Africa is expected to join, possibly followed by a second U.S. funder. Others around the world are considering whether to sign on. Plan S, scheduled to take effect on 1 January 2020, has drawn support from many scientists, who welcome a shake-up of a publishing system that can generate large profits while keeping taxpayer-funded research results behind paywalls. But publishers (including AAAS, which publishes Science) are concerned, and some scientists worry that Plan S could restrict their choices.
DS1960-0379
1963
Rabhkin, M.I.Milashev, V.A., Krutoyarski, M.A., Rabhkin, M.I., Ehrlich, E.N.Kimberlitic Rocks and Picritic Porphyries of the North Eastern Part of the Siberian PlatformNiiga., Gosgeoltekizdat., Vol. 126, PP. 1-10.5.RussiaMineral Chemistry
DS202004-0504
2020
Rabinovich, O.IChernykh, S.V., Chernykh, A.V., Tarelkin, S., Didenko, S. ,Kondakov, M.N., Shcherbachev, K.D., Trifonova, E.V., Drozdova, T.E., Troschiev, S.Y., Prikhodko, D.D., Glybin, Y.N., Chubenko, A.P., Britvich, G.I., Kiselev, D.A., Polushin, N.I., Rabinovich, O.IHPHT single crystal diamond type IIa characterization for particle detectors.Physicsa Status Solidi , doi:10.1002/pssa.201900888GlobalHPHT

Abstract: Various samples of multisectoral high?pressure high?temperature (HPHT) single?crystal diamond plate (IIa type) (4?×?4?×?0.53?mm) are tested for particle detection applications. The samples are investigated by X?ray diffractometry, photoluminescence spectroscopy, Raman spectroscopy, Fourier?transform infrared, and visible/ultraviolet (UV) absorption spectroscopy. High crystalline perfection and low impurity concentration (in the {100} growth sector) are observed. To investigate detector parameters, circular 1.0 and 1.5?mm diameter Pt Schottky barrier contacts are created on {111} and {100} growth sectors. On the backside, a Pt contact (3.5?×?3.5?mm) is produced. The {100} growth sector is proved to be a high?quality detector: the full width at half maximum energy resolution is 0.94% for the 5.489?MeV 226Ra ??line at an operational bias of +500?V. Therefore, it is concluded that the HPHT material {100} growth sector is used for radiation detector production, whose quality is not worse than the chemical vapor deposition method or specially selected natural diamond detectors.
DS1988-0473
1988
Rabinowicz, M.Mimouni, A., Rabinowicz, M.The old continental shields stability related to mantle convectionGeophysical Research Letters, Vol. 15, No. 1, January pp. 68-71GlobalBlank
DS1993-0230
1993
Rabinowicz, M.Ceuleneer, G., Monnereau, M., Rabinowicz, M., Rosemberg, C.Thermal and petrological consequences of melt migration within mantleplumesPhilosophical Transactions Royal Society of London, Section A, Vol. 342, pp. 53-64MantleGeochemistry, plume model, Alkaline rocks
DS2000-0246
2000
Rabinowicz, M.Dubuffet, F., Rabinowicz, M., Monnereau, M.Multiple scales in mantle convectionEarth and Planetary Science Letters, Vol. 178, No. 3-4, May 30, pp. 351-66.MantleSubduction, Convection
DS2002-1295
2002
Rabinowicz, M.Rabinowicz, M., Ricard, Y., Gregoire, M.Compaction in a mantle with a very small melt concentration: implications for theEarth and Planetary Science Letters, Vol. 203, 1, pp. 205-220.MantleMagmatism, Carbonatite, Geochemistry
DS200612-1086
2006
Rabinowicz, M.Petitjean, S., Rabinowicz, M., Gregoire, M., Chevrot, S.Differences between Archean and Proterozoic lithospheres: assessment of the possible major role of thermal conductivity.Geochemistry, Geophysics, Geosystems: G3, Vol. 7, Q03021 10.1029/2005 GC001053MantleGeothermometry
DS200712-0894
2007
Rabinowicz, M.Richard, G., Monnereau, M., Rabinowicz, M.Slab dehydration and fluid migration at the base of the upper mantle: implications for deep earthquake mechanisms.Geophysical Journal International, Vol. 168, 3, pp. 1291-1304.MantleSlab melting
DS202105-0785
2021
Rabinowitz, Y.Rabinowitz, Y., Etinger, A., Litvak, B., Yahalom, A., Cohen, H., Pinhasi, Y.Millimeter wave spectroscopy for evaluating diamond color grades.Diamond & Related Materials, Vol. 116, 108386 10p. PdfGlobalspectroscopy

Abstract: One of the most important parameters affecting the value of natural colorless diamonds is its light transparency, defined as its color grade. The regular range of color grades in the trade is denoted by alphabet letters in the range D-M, where D represents the best commercial quality. The color grade of diamonds is largely influenced by their nitrogen content (when nitrogen atoms substitute carbon atoms in the crystal) and can be determined from this property. Diamonds absorb electromagnetic radiation in the UV-visible as well as in the Infrared spectral range and therefore, their color grade is measured via spectroscopic light absorption in these frequency range. The electromagnetic properties of different polished diamonds having several nitrogen concentrations in the frequency range of 100-110 GHz (W band) have been studied. The results indicate that there is a good correlation between the amount of nitrogen impurities and the Free Spectral Range (FSR) parameter of a reflection signal, S11, in the antenna. From the study It is concluded that measuring the diamonds dielectric properties via spectroscopic analysis in the millimeter wavelength range, can determine the color grading. In addition, the FSR measurements were correlated well with the FTIR measurements. The methodology of the new color determination mode and a novel color estimate, based on the FSR vs the nitrogen correlation, has been tested on 26 diamonds with a success rate higher than 70%.
DS1950-0422
1958
Rabkin, M.I.Rabkin, M.I., Solov'yev, D.S.Kimberlites and Diamond Deposits of the Middle Course of The Olenek River.Leningrad: Niiga., Vol. 97.RussiaBlank
DS1960-0085
1960
Rabkin, M.I.Rabkin, M.I., Milashev, V.A.Kimberlite Volcanism of the Northern Part of the Siberian Platform.Niiga., Vol. 114, No. L4.RussiaBlank
DS1960-0162
1961
Rabkin, M.I.Krutoyarskii, M.A., Milashev, V.A., Rabkin, M.I.The Classification of Kimberlitic Rocks of YakutiaNiiga, Info. Bulletin., Vol. 23, PP. 23-26.RussiaBlank
DS1960-0289
1962
Rabkin, M.I.Rabkin, M.I., Krutoyarski, M.A., Milashev, V.A.Classification and Nomenclature of Yakutian KimberlitesNiiga., Vol. 121, PP. 154-164.RussiaBlank
DS1960-0290
1962
Rabkin, M.I.Rabkin, M.I., Milashev, V.A.Volcanic Kimberlites of the North Siberian CratonIn: Symposium On The Geology of The Arctic. International Geol. Re, Vol. 5, No. 7, PP.RussiaBlank
DS1960-0381
1963
Rabkin, M.I.Milashev, V.A., Rabkin, M.I.Kimberlites of the Anabar-olenek Region and Problems of Their Origin.Akad. Nauk Sssr Sib. Div. Yakut., No. 9, PP. 45-53.RussiaBlank
DS1970-0315
1971
Rabkin, M.I.Ilupin, I.P., Rabkin, M.I.Chemical Composition Characteristics of Ilmenite from Kimberlites.Leningrad: Nauch. Issled. Institute Geol. Arktiki, PP. 85-89.Russia, DaldynBlank
DS1970-0391
1971
Rabkin, M.I. EDITOR.Rabkin, M.I. EDITOR.Kimberlitovye Vulkanizm I Perspektivy Korennoi Almazonosnostii Severo- Vostoka Sibirskoi Platformy.Leningrad: N I I G A, 157P.RussiaKimberlite, Kimberley, Janlib
DS1996-0988
1996
Rabonowicz, M.Monnereau, M., Rabonowicz, M.Is the 670 km phase transition able to layer Earth's convection in a mantle with depth dependent viscosity?Geophysical Research Letters, Vol. 23, No. 9, May 1, pp. 1001-1004.MantleStratigraphy, Transition phase
DS200612-0496
2005
Rabonowicz, M.Gregoire, M., Rabonowicz, M., Janse, A.J.A.Mantle mush compaction: a key to understand the mechanisms of concentration of kimberlite melts and initiation of swarms of kimberlite dykes.Journal of Petrology, Vol. 47, 3, March, pp. 631-646,Africa, South Africa, Lesotho, BotswanaConvection, Kimberley, Rietfontein, Central Cape,Gibeon
DS1975-1190
1979
Raby, A.G.Raby, A.G., et al.Geochemical Model for the Origin of Archean Diabase Dikes from the eastern Beartooth Mountains Montana and Wyoming.Guide To The Precambrian Rocks of The Beartooth Mountains, I, P. A14, (abstract.).Montana, WyomingKimberlite, Lherzolite, Rocky Mountains, Geochemistry
DS200812-1027
2008
Racek, M.Schulmann, K., Lexa, O., Stipska, P., Racek, M., Tajcmanova, L., Konpasek, Edel, Peschler, LehmannVertical extension and horizontal channel flow of orogenic lower crust: key exhumation mechanisms in large hot orogens?Journal of Metamorphic Geology, In press availableEurope, MantleGeophysics - bouguer
DS201810-2311
2018
Racek, M.Faryad, S.W., Jedlicka, R., Hauzenberger, C., Racek, M.High pressure crystallization vs. recrystallization origin of garnet pyroxenite-eclogite within subduction related lithologies. Bohemian MassifMineralogy and Petrology, Vol. 112, 5, pp. 603-616.Europe, Austriasubduction

Abstract: Mafic layers displaying transition between clinopyroxenite and eclogite within peridotite from felsic granulite in the Bohemian Massif (Lower Austria) have been investigated. The mafic-ultramafic bodies shared a common granulite facies metamorphism with its hosting felsic rocks, but they still preserve evidence of eclogite facies metamorphism. The selected mafic layer for this study is represented by garnet with omphacite in the core of coarse-grained clinopyroxene, while fine-grained clinopyroxene in the matrix is diopside. In addition, garnet contains inclusions of omphacite, alkali feldspars, hydrous and other phases with halogens and/or CO2. Textural relations along with compositional zoning in garnet from the clinopyroxenite-eclogite layers favour solid-state recrystallization of the precursor minerals in the inclusions and formation of garnet and omphacite during subduction. Textures and major and trace element distribution in garnet indicate two stages of garnet growth that record eclogite facies and subsequent granulite facies overprint. The possible model explaining the textural and compositional changes of minerals is that the granulite facies overprint occurred after formation and exhumation of the eclogite facies rocks.
DS1997-0939
1997
Rachamalla, K.Rachamalla, K.India offers increased mining opportunities for foreign companiesMining Engineering, Vol. 49, No. 2, Feb. pp. 46-47.IndiaMining - laws, Legal
DS202205-0706
2022
Rachetti, A.Meisel, T.C., Webb, P.C. , Rachetti, A.Highlights from 25 years of the GeoPT programme: what can be learnt for the advancement of geoanalysis. Geostandards and Geoanalytical Research, 21p. Open accessGlobalGeoPT

Abstract: Data submitted over the past 25?years to GeoPT, the highly successful proficiency-testing programme for the geochemical analysis of geological materials, organised by the International Association of Geoanalysts, provide a valuable resource that permits detailed investigation of contrasting results associated with different sample preparation and measurement principles. Highlighted issues include the following: recurring problems with the dissolution of the refractory minerals zircon and chromite, which produce a large dispersion in data obtained when acid digestion is involved; issues related to different XRF sample preparation methods, whereby a significant divergence of pressed powder pellet results compared with those from fused glass discs is observed; high relative dispersion of data both at low mass fractions, and those higher than normally found in silicate rocks, due to incomplete method validation, in particular due to an overconfidence in estimating reporting limits and to the employment of limited working ranges. In addition, an example for Sr in an ancient pegmatite with extremely high Rb abundance is presented, where ICP-MS results amount to only to a third of the XRF results, severely underestimated due to the disregard of the radiogenic ingrowth from 87Rb decay. Recommendations are made both for improving data quality and the selection of test materials for future GeoPT rounds.
DS1999-0820
1999
Rachibana, T.Yoshimoto, M., Yoshida, K., Rachibana, T.Epitaxial diamond growth on sapphire in an oxidizing environmentNature, Vol. 399, No. 6734, May 27, pp. 340-341.GlobalDiamond - morphology
DS201212-0018
2012
Rachid, F.Araujo, D.P., Silveira, F.V., Weska, R.K., Rachid, F., Neto, F.E.B., Ireland, T., Holden, P., Gobbo, L.Diamonds from the Sao Francisco and Amazon cratons, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Andari, Lencois, Barra do Mendes, Catalao, Frutal
DS200612-0591
2006
Rachid Houari, M.Hoepffner, C., Rachid Houari, M., Bouabdelli, M.Tectonics of the North African Variscides ( Morocco, western Algeria) - an outline.Comptes Rendus Geoscience, Vol. 338, 1-2, pp. 25-Africa, MoroccoTectonics
DS1989-1310
1989
Rachkov, V.S.Rozen, O.M., Nozhkin, A.D., Zlobin, V.L., Rachkov, V.S.Distribution of radioactive elements in the metamorphic rocks of the Anabar shield: origin of the rocks and evolution of the crustInternational Geology Review, Vol. 31, No. 8, August pp. 780-791RussiaAnabar shield, metamorphism
DS1997-0940
1997
Rachmalla, K.Rachmalla, K.India offers increased mining opportunities for foreign companiesMining Engineering, Vol. 49, No. 2, Feb. pp. 46-47IndiaMining, Legal
DS1997-0741
1997
Rachmalla, K.S.Mason, J.D., Rachmalla, K.S.Exploration financing - innovative approach lowers risk17th. World Mining Congress Oct. Mexico, pp. 459-470CanadaEconomics, discoveries, Risk Financing
DS1995-1537
1995
Rada, R.Rada, R.Interactive mediaSpringer Verlag, 256pGlobalInteractive media, Book -ad
DS1989-1542
1989
Radbruch-Hall, D.H.Varnes, D.J., Radbruch-Hall, D.H., Savage, W.Z.Topographic and structural conditions in areas of gravitational spreading of ridges in the western United StatesUnited States Geological Survey (USGS) Prof. Paper, No. 1496, 28pColorado, MontanaStructure, General-specific regions
DS2002-1296
2002
Raddick, M.J.Raddick, M.J., Parmentier, E.M., Scheirer, D.S.Buoyant decompression melting: a possible mechanism for intraplate volcanismJournal of Geophysical Research, Oct. 29, 10.1029/2001JB000617.MantleMelting, Magmatism
DS200812-0465
2008
Rademan, J.Herbst, J., Potapov, A., Hambidge, G., Rademan, J.Modeling of diamond liberation and damage for Debswana kimberlitic ores.Minerals Engineering, Vol. 21, 11, October pp. 766-789.Africa, BotswanaMining - mineral processing
DS201901-0037
2018
Radeneyer, M.Grantham, G., Eglinton, B., Macey, P.H., Ingram,B., Radeneyer, M., Kaiden, H., Manhica, V.The chemistry of Karoo age andesitic lavas along the northern Mozambique coast, southern Africa and possible implications for Gondwana breakup.South African Journal of Geology, Vol. 121, pp. 271-286.Africa, Mozambiquegeodynamics

Abstract: Major, trace, radiogenic isotope and stable isotope data from lavas along the northeastern coast of Mozambique are described. The whole rock composition data demonstrate that the rocks are dominantly andesitic with compositions typical of calc-alkaline volcanic rocks from arc environments. SHRIMP U/Pb data from zircons indicate that the zircons are xenocrystic, having ages of between 500 Ma and 660 Ma, with the age of the lava constrained by Rb/Sr data at ~184 Ma. Strontium, Nd and Pb radiogenic isotope data support an interpretation of extensive mixing between a Karoo age basaltic magma (dolerite) from Antarctica and continental crust similar in composition to the Mozambique basement. Oxygen isotope data also imply a significant crustal contribution to the lavas. Possible tectonic settings for the lavas are at the margin of a plume or from a locally restricted compressional setting during Gondwana breakup processes.
DS1990-1208
1990
Radetzki, M.Radetzki, M.Economic development and the timing of mineral exploitation: a critical review of some conventional wisdomsColorado School of Mines, Department of Mineral Economics, Working Paper, No. 89-8, February 13pGlobalEconomics, Mineral exploitation -timing
DS1994-1423
1994
Radetzki, M.Radetzki, M.Mineral exploitation - regional development in a historical perspectiveRaw Materials Report, Vol. 10, No. 1, pp. 2-7GlobalEconomics, Mineral resource development
DS1994-1424
1994
Radhakri, B.P.Radhakri, B.P.New thinking on diamond explorationJournal of Geological Society India, Vol. 44, No. 4, October p. 366.IndiaDiamond exploration
DS1996-1152
1996
Radhakri, S.P.Radhakri, S.P.Diamond formation in uranium rich carbonaceous matterJournal of Geological Society India, Vol. 48, No. 5, Nov. p. 592.IndiaDiamond genesis, UraniuM.
DS200612-1120
2006
Radhakrishna, B.P.Radhakrishna, B.P.Some thoughts on diamond exploration in India.Journal of the Geological Society of India, Vol. 67, pp. 283-288.IndiaDiamond exploration - brief overview
DS1994-1425
1994
Radhakrishna, T.Radhakrishna, T., Dallmeyer, R.D., Joseph, M.Paleomagnetism and 36 Ar-40 Ar vs 39 Ar-40 Ar isotope correlation ages of dyke swarms in central Kerala, India: tectonic implications.Earth and Planetary Science Letters, Vol. 121, No. 1/2, January pp. 213-226.IndiaDikes, isotope correlation, Argon, Tectonics
DS1994-1426
1994
Radhakrishna, T.Radhakrishna, T., Dallmeyer, R.D., Joseph, M.Paleomagnetism and 36 Ar-40Ar vs 39Ar-40r isotope correlation ages of dyke swarms in central Kerala, India: tectonic implications.Earth and Planetary Science Letters, Vol. 121, pp. 213-226.IndiaPaleomagnetics, Argon, Dykes
DS1996-1153
1996
Radhakrishna, T.Radhakrishna, T., et al.Proterozoic paleomagnetism of the mafic dyke swarms in the high grade region of southern India.Precambrian Research, Vol. 76, No. 1, 2, Jan. 1, pp. 31-46.IndiaDyke swarms, Geophysics -Paleomagnetism
DS1998-1201
1998
Radhakrishna, T.Radhakrishna, T., Joseph, M.Geochemistry and petrogenesis of the Proterozoic dikes in Tamil Nadu:another example of Archean lithosphericGeol. Rundsch., Vol. 87, No. 3, Dec. pp. 268-82.India, southern IndiaDike - mantle source
DS2003-1122
2003
Radhakrishna, T.Radhakrishna, T., Joseph, M., Krishnendu, N.R., Balasubramonian, G.Paleomagnetism of mafic dykes in Dharwar Craton: possible geodynamic implicationsGeological Society of India Memoir, No. 50, pp. 193-224.IndiaGeophysics - magnetics
DS200412-1608
2003
Radhakrishna, T.Radhakrishna, T., Joseph, M., Krishnendu, N.R., Balasubramonian, G.Paleomagnetism of mafic dykes in Dharwar Craton: possible geodynamic implications.Geological Society of India Memoir, No. 50, pp. 193-224.IndiaGeophysics - magnetics
DS201312-0726
2013
Radhakrishna, T.Radhakrishna, T., Chandra, R., Srivastava, A.K., Balasubramonian, G.Central/eastern Indian Bundelk hand and Bastar cratons in the Paleoproterozoic supercontinental reconstructions: a paleomagnetic perspective.Precambrian Research, Vol. 226, pp. 91-104.IndiaPaleomagnetism
DS201312-0727
2013
Radhakrishna, T.Radhakrishna, T., Krishnendu, N.R., Balasubramonian, G.Nd-Hf isotope systematics of megacrysts from the Mbuji-Mayi kimberlites, D.R. Congo: evidence for a metasomatic origin related to kimberlite interaction with the cratonic lithosphere mantle.Earth Science Reviews, in press availableIndiaGondwana
DS201312-0728
2013
Radhakrishna, T.Radhakrishna, T., Krishnendu, N.R., Balasubramonian, G.Paleoproterozoic Indian shield in the global continental assembly: evidence from the paleomagnetism of mafic dyke swarms.Earth Science Reviews, Vol. 126, pp. 370-389.IndiaDykes
DS201709-2045
2017
Radhakrishna, T.Radhakrishna, T., Soumya, G.S., Satyanarayana, K.V.V.Paleomagnetism of the Cretaceous lamproites from Gondwana basin of the Damodar Valley in India and migration of the Kerguelen plume in the southeast Indian Ocean.Journal of Geodynamics, Vol. 109, pp. 1-9.Indialamproites

Abstract: The paper presents new palaeomagnetic results and reassesses complete set of published palaeomagnetic results on the lamproite intrusions in the Gondwana formations of the Eastern India. Altogether eleven sites register reliable characteristic magnetisations corresponding to the c. 110 Ma emplacement age of the lamproites. A mean ChRM is estimated with D = 331.3°; I = ?62.4° (?95 = 6.2°, k = 55; N = 11). The palaeomagnetic pole of ? = 14.9°: ? = 287.6° (A95 = 8.4°) is established for the lamproites and it averaged the secular variation and confirms to the Geocentric Axial Dipole (GAD). The pole compares remarkably well with the grand mean pole reported for the Rajmahal traps that are attributed to represent location of the Kerguelen mantle plume head. The palaeolatitudes transferred to Rajmahal coordinates (25.05°: 87.84°) are situated ?6° north of the present location of the Kerguelen hotspot location. The interpretations are consistent with earlier suggestions of southward migration of the plume based on palaeomagnetic results of Site 1138 of the ODP Leg 183 and with the predictions of numerical models of global mantle circulation.
DS1990-1209
1990
Radhakrishna Murthy, I.V.Radhakrishna Murthy, I.V., Krishnamacharyulu, S.K.G.Automatic inversion of gravity anomalies of faultsComputers and Geosciences, Vol. 16, No. 4, pp. 539-548GlobalComputer, Program -faults/gravity
DS1988-0560
1988
Radhakrishnamurty, C.Radhakrishnamurty, C., Likhite, S.D., Murthy, G.S.Magnetic studies on the remanence carriers in Igneous rocks of differentagesProceedings of the Indian Academy of Sciences, Vol. 97, No. 1, July pp. 81-86IndiaGeophysics
DS1997-0941
1997
Radhakrishnan, V.Radhakrishnan, V., Mariappan, N., Thrivikramji, L.P.A QUICKBASE program to analyse pebble shapesComputers and Geosciences, Vol. 23, No. 3, pp. 325-327.GlobalZingg shape classification, Alluvials, placers, pebbles
DS2002-0284
2002
RadigonCheng, L.Z., Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., RadigonSimultaneous inversion of gravity and heat flow data: constraints on thermal regimeJournal of Geodynamics, Vol. 34, 1, pp. 11-30.Ontario, ManitobaGeothermometry, Lithosphere - Abitibi subprovince, Thompson Belt
DS200612-0384
2006
Radina, E.S.Evdokimov, A.N., Burnaeva, M.Yu., Radina, E.S., Sirotkin, A.N.The first find of kimberlitic accessory minerals in mafic-ultramafic dikes in Spitsbergen.Doklady Earth Sciences, Vol. 407, 2, Feb-Mar. pp. 275-279.Europe, NorwayGeochemistry
DS1985-0552
1985
Radionov, A.S.Radionov, A.S., Sobolev, N.V.A New Find of Graphite Containing Harzburgite Xenoliths Inkimberlite.(russian)Geol. Geofiz., (Russian), No. 12, pp. 32-37RussiaHarzburgite
DS1970-0566
1972
Radionov, M.N.Molochnov, G.V., Radionov, M.N., Genin, B.L.Use of Dipole Electric-magnetic Sounding in Determining The thickness of Alluvium During Exploration for Beach Diamond Placers in the Region of Anabar Bay.Geofiz. Metody Razved. Arkt., No. 7, PP. 68-73.Russia, YakutiaKimberlite, Geophysics
DS202112-1927
2021
Radiquet, B.Gardes, E., Gilbouin, D., Radiquet, B., David, A., Prellier, W., Marquardt, K.Magnesium transport in olivine mantle: new insights from miniturized study of volume and grain boundary diffusion in Mg2Si04 bi-crystals.Contribution to Mineralogy and Petrology, Vol. 176, 99 16p. PdfMantleolivine

Abstract: We report experimental measurements of volume and grain boundary diffusion of 26Mg in Mg2SiO4 bi-crystals at asthenosphere temperatures as a ground reference for olivine. By analysis of literature and combination with previous data, we provide Arrhenius laws D = D0 exp(- E/RT) at ambient pressure for volume diffusion of Mg in Mg2SiO4 in the intrinsic regime along the three crystallographic axes as well as grain boundary diffusion.
DS1991-1393
1991
Radko, V.A.Radko, V.A.Model of dynamic differentiation of intrusive traps in the northwestern Siberian PlatformSoviet Geology and Geophysics, Vol. 32, No. 11, pp. 15-20RussiaLayered intrusions, platinum group elements (PGE), Nickel
DS202009-1634
2020
Radomskaya, T.A.Kaneva, E., Shendrik, R.Yu., Radomskaya, T.A., Suvorova, L.E.Fedorite from Murun alkaline complex ( Russia): spectroscopy and crystal chemical features.Minerals ( MDPI), Vol. 10, 702, 24p. PdfRussiadeposit - Murun

Abstract: Fedorite is a rare phyllosilicate, having a crystal structure characterized by SiO4-tetrahedral double layers located between continuous layers formed by edge-sharing (Ca,Na)-octahedra, and containing interlayer K, Na atoms and H2O molecules. A mineralogical-petrographic and detailed crystal-chemical study of fedorite specimens from three districts of the Murun alkaline complex was performed. The sequence of the crystallization of minerals in association with fedorite was established. The studied fedorite samples differ in the content of interlayer potassium and water molecules. A comparative analysis based on polyhedral characteristics and deformation parameters was carried out. For the first time, EPR, optical absorption and emission spectra were obtained for fedorite. The raspberry-red coloration of the mineral specimens could be attributed to the presence of Mn4+ ions.
DS202010-1847
2020
Radomskaya, T.A.Kaneva, E.V., Shendrik, R.Yu., Radomskaya, T.A., Suvorova, L.F.Fedorite from Murun alkaline complex ( Russia): spectroscopy and crystal chemical features.Minerals, Vol. 10, 702 10.3390/min10080702 24p. PdfRussia, Yakutiadeposit - Murun

Abstract: Fedorite is a rare phyllosilicate, having a crystal structure characterized by SiO4-tetrahedral double layers located between continuous layers formed by edge-sharing (Ca,Na)-octahedra, and containing interlayer K, Na atoms and H2O molecules. A mineralogical-petrographic and detailed crystal-chemical study of fedorite specimens from three districts of the Murun alkaline complex was performed. The sequence of the crystallization of minerals in association with fedorite was established. The studied fedorite samples differ in the content of interlayer potassium and water molecules. A comparative analysis based on polyhedral characteristics and deformation parameters was carried out. For the first time, EPR, optical absorption and emission spectra were obtained for fedorite. The raspberry-red coloration of the mineral specimens could be attributed to the presence of Mn4+ ions.
DS202107-1112
2021
Radomskaya, T.A.Marfin, A., Radomskaya, T.A., Ivanov, A.V., Belozerova, O.Y.U-Pb dating of apatite, titanite and zircon of the Kingash mafic-ultramafic massif, Kan terrane Siberia: from Rodinia break-up to the reunion of the Siberian craton.Journal of Petrology, Vol. 62, 6, EGAb049Russia, Siberiacratons

Abstract: The initial stage of Rodinia supercontinent break-up occurred at about 750?Ma. It preceded formation of the Irkutsk and Franklin Large Igneous Provinces (LIPs)at 712 ± 2?Ma to 739 ± 8?Ma. These LIPs were emplaced within the formerly connected Laurentian and Siberian cratons. The Kingash massif is located in the Precambrian Kan terrane in direct contact with the Siberian Craton at its southwestern boundary. It has been linked to an important suite of mafic-ultramafic intrusions which border the southern margin of the Siberian craton, and which have been inferred to belong to the Irkutsk LIP. The massif is also significant, because it hosts PGE-Cu-Ni rich mineralization and is the only large deposit in the region. However, despite numerous dating attempts, the age of the massif had not been resolved. A significant difficulty is post-magmatic recrystallization at amphibolite facies that affected the rocks of the massif. In this study we used U-Pb dating of zircon, titanite and apatite from rocks of the Kingash massif and cross-cutting granite and monzonite veins. The oldest igneous zircon grain of the Kingash massif analysed by LA-ICPMS yields an age of c. 750?Ma, taken as a tentative age of magmatism. Dating of multiple grains of metamorphic zircon by CA-ID-TIMS yielded 564.8 ± 2.2?Ma, which is in agreement with LA-ICPMS titanite ages 557 ± 19?Ma, 565 ± 35?Ma and 551 ± 17?Ma. Apatite of two different samples showed ages of 496.4 ± 7.9?Ma and 497.0 ± 1.8?Ma (LA-ICPMS), which are interpreted as the time when the terrane cooled below the closure temperature of apatite. Using our new data we suggest that at the time of the Irkutsk-Franklin LIP event the Kan terrane was a part of Rodinia, then it separated from either Siberia or Laurentia during the break-up of Rodinia and finally collided with Siberia at 560?Ma; the time of regional amphibole facies metamorphism.
DS201709-2046
2017
Radu, I.B.Radu, I.B., Harris, C., Moine, B., Costin, G., Cottin, J-Y.Subduction relics in the cratonic root - evidence from delta O18O variations in eclogite xenoliths.Goldschmidt Conference, abstract 1p.Africa, South Africadeposit, Roberts Victor, Jagersfontein
DS202009-1641
2020
Radu, I.B.Moine, B.N., Bolfan-Casanova, N., Radu, I.B., Ionov, D.A., Costin, G., Korsakov, A.V., Golovin, A.V., Oleinikov, O.B., Deloule, E., Cottin, J.Y.Molecular hydrogen in minerals as a clue to interpret deltaD variations in the mantle. ( Omphacites from eclogites from Kaapvaal and Siberian cratons.)Nature Communications, doi:.org/10.1038/ s41467-020-17442 -8 11p. PdfAfrica, South Africa, Russia, Siberiawater

Abstract: Trace amounts of water dissolved in minerals affect density, viscosity and melting behaviour of the Earth’s mantle and play an important role in global tectonics, magmatism and volatile cycle. Water concentrations and the ratios of hydrogen isotopes in the mantle give insight into these processes, as well as into the origin of terrestrial water. Here we show the presence of molecular H2 in minerals (omphacites) from eclogites from the Kaapvaal and Siberian cratons. These omphacites contain both high amounts of H2 (70 to 460 wt. ppm) and OH. Furthermore, their ?D values increase with dehydration, suggesting a positive H isotope fractionation factor between minerals and H2-bearing fluid, contrary to what is expected in case of isotopic exchange between minerals and H2O-fluids. The possibility of incorporation of large quantities of H as H2 in nominally anhydrous minerals implies that the storage capacity of H in the mantle may have been underestimated, and sheds new light on H isotope variations in mantle magmas and minerals.
DS201607-1373
2016
Radu, I-B.Radu, I-B.Kyanite bearing eclogite xenoliths from the Udachanaya kimberlites, Siberia.IGC 35th., Session A Dynamic Earth 1p. AbstractRussiaKimberlite
DS201710-2259
2017
Radu, I-B.Radu, I-B., Moine, B., Ionov, D., Korsakov, A., Golovin, A., Mikhailenko, D., Cottin, J-Y.Kyanite-bearing eclogite xenoliths from the Udachnaya kimberlite, Siberian craton, Russia.Bulletin de la Societe Geologique de France *eng, Vol. 188, 1-2, 14p.Russia, Siberiadeposit - Udachnaya

Abstract: Xenoliths brought up by kimberlite magmas are rare samples of otherwise inaccessible lithospheric mantle. Eclogite xenoliths are found in most cratons and commonly show a range of mineral and chemical compositions that can be used to better understand craton formation. This study focuses on five new kyanite-bearing eclogites from the Udachnaya kimberlite pipe (367±5 Ma). They are fine-to coarse-grained and consist mainly of “cloudy” clinopyroxene (cpx) and garnet (grt). The clinopyroxene is Al,Na-rich omphacite while the garnet is Ca-rich, by contrast to typical bi-mineral (cpx+grt) eclogites that contain Fe- and Mg-rich garnets. The Udachnaya kyanite eclogites are similar in modal and major element composition to those from other cratons (Dharwar, Kaapvaal, Slave, West African). The kyanite eclogites have lower REE concentrations than bi-mineral eclogites and typically contain omphacites with positive Eu and Sr anomalies, i.e. a “ghost plagioclase signature”. Because such a signature can only be preserved in non-metasomatised samples, we infer that they were present in the protoliths of the eclogites. It follows that subducted oceanic crust is present at the base of the Siberian craton. Similar compositions and textures are also seen in kyanite eclogites from other cratons, which we view as evidence for an Archean, subduction-like formation mechanism related to craton accretion. Thus, contrary to previous work that classifies all kyanite eclogites as type I (IK), metasomatized by carbonatite/kimberlitic fluids, we argue that some of them, both from this work and those from other cratons, belong to the non-metasomatized type II (IIB). The pristine type IIB is the nearest in composition to protoliths of mantle eclogites because it contains no metasomatic enrichments.
DS1996-1082
1996
Radwanek-Bak, B.Paulo, A., Radwanek-Bak, B.The mineral industry of the Ukraine - a reviewErzmetall, Vol. 49, No. 1, Jan. pp. 61-69UKraineMineral industry, Review
DS200712-0964
2007
Radziminovich, Y.A.Seminskii, K., Radziminovich, Y.A.Seismicity of the southern Siberian platform: spatiotemporal characteristics and genesis.Izvestia, Physics of the Solid Earth, Vol. 43, 9, Sept., pp. 726-737. IngentaRussiaGeophysics - seismics
DS200812-1083
2008
Radziminovich, Ya.B.Smininsky, K.Zh., Gladkov, A.S., Radziminovich, Ya.B., Cheremnykh, A.V., Bobrov, A.A.Regularities of manifestation of active faults and seismicity in the southern part of the Siberian craton.Doklady Earth Sciences, Vol. 422, 1, October pp. 1068-1972.Russia, SiberiaGeophysics - seismics
DS1993-0790
1993
Raeburn, S.P.Kasting, J.F., Eggler, D.H., Raeburn, S.P.Mantle redox evolution and the oxidation state of the Archean atmosphereJournal of Petrology, Vol. 101, No. 2, March pp. 245-258MantleXenoliths, Geochemistry
DS201905-1069
2019
Raeisi, D.Raeisi, D., Gholoizade, K., Nayebi, N., Babazadeh, S., Nejadhadad, M.Geochemistry and mineral composition of lamprophyre dikes, central Iran: implications for petrogenesis and mantle evolution.Journal of Earth System Science, Vol. 128:74Europe, Iranlamprophyre

Abstract: Late Proterozoic-Early Cambrian magmatic rocks that range in composition from mafic to felsic have intruded into the Hour region of the central Iranian micro-continent. The Hour lamprophyres are alkaline, being characterized by low contents of SiO2 and high TiO2, Mg# values, high contents of compatible elements, and are enriched in LREE and LILE but depleted in HFSE. Mineral chemistry studies reveal that the lamprophyres formed within a temperature range of ?1200? to 1300?C and relatively moderate pressure in subvolcanic levels. The Hour lamprophyres have experienced weak fractional crystallization and insignificant crustal contamination with more primitive mantle signatures. They were derived from low degree partial melting (1-5%) of the enriched mantle characterized by phlogopite/amphibole bearing lherzolite in the spinel-garnet transition zone at 75-85 km depth, and with an addition of the asthenospheric mantle materials. We infer the Hour lamprophyres to be part of the alkaline rock spectrum of the Tabas block and their emplacement, together with that of other alkaline complexes in the central Iran, was strongly controlled by pre-existing crustal weakness followed by the asthenosphere-lithospheric mantle interaction during the Early Cambrian.
DS201412-0640
2014
Raepsaet, C.Novella, D., Frost, D.J., Hauri, E.H., Bureau, H., Raepsaet, C., Roberge, M.The distribution of H2O between silicate melt and nominally anhydrous peridotite and the onset of hydrous melting in the deep upper mantle.Earth and Planetary Science Letters, Vol. 400, pp. 1-13.MantleMelting
DS201706-1101
2017
Raepsaet, C.Roberge, M., Bureau, H., Bolfan-Casanova, N., Raepsaet, C., Surble, S., Khodja, H., Auzende, A-L., Cordier, P., Fiquet, G.Chlorine in wadsleyite and ringwoodite: an experimental study.Earth and Planetary Science Letters, Vol. 467, pp. 99-107.Mantlechlorine

Abstract: We report concentrations of Chlorine (Cl) in synthetic wadsleyite (Wd) and ringwoodite (Rw) in the system NaCl-(Mg,?Fe)2SiO4 under hydrous and anhydrous conditions. Multi-anvil press experiments were performed under pressures (14-22 GPa) and temperatures (1100-1400?°C) relevant to the transition zone (TZ: 410-670 km depth). Cl and H contents were measured using Particle Induced X-ray Emission (PIXE) and Elastic Recoil Detection Analysis (ERDA) respectively. Results show that Cl content in Rw and Wd is significantly higher than in other nominally anhydrous minerals from the upper mantle (olivine, pyroxene, garnet), with up to 490 ppm Cl in anhydrous Rw, and from 174 to 200 ppm Cl in hydrous Wd and up to 113 ppm Cl in hydrous Rw. These results put constrains on the Cl budget of the deep Earth. Based on these results, we propose that the TZ may be a major repository for major halogen elements in the mantle, where Cl may be concentrated together with H2OH2O and F (see Roberge et al., 2015). Assuming a continuous supply by subduction and a water-rich TZ, we use the concentrations measured in Wd (174 ppm Cl) and in Rw (106 ppm Cl) and we obtain a maximum value for the Cl budget for the bulk silicate Earth (BSE) of 15.1 × 1022 g Cl, equivalent to 37 ppm Cl. This value is larger than the 17 ppm Cl proposed previously by McDonough and Sun (1995) and evidences that the Cl content of the mantle may be higher than previously thought. Comparison of the present results with the budget calculated for F (Roberge et al., 2015) shows that while both elements abundances are probably underestimated for the bulk silicate Earth, their relative abundances are preserved. The BSE is too rich in F with respect to heavy halogen elements to be compatible with a primordial origin from chondrites CI-like (carbonaceous chondrites CC) material only. We thus propose a combination of two processes to explain these relative abundances: a primordial contribution of different chondritic-like materials, including EC-like (enstatite chondrites), possibly followed by a distinct fractionation of F during the Earth differentiation due to its lithophile behavior compared to Cl, Br and I.
DS201904-0757
2019
Raepsaet, C.Malavergegne, V., Bureau, H., Raepsaet, C., Gaillard, C., Poncet, F., Surble, M., Sifre, S., Shcheka, D., Fourdrin, S., Deldicque, C., Khodja, D., HichamExperimental constraints on the fate of H and C during planetary core-mantle differentiation. Implications for the Earth.Icarus - New York, Vol. 321, 1, pp. 473-485.Mantlecarbon

Abstract: Hydrogen (H) and carbon (C) have probably been delivered to the Earth mainly during accretion processes at High Temperature (HT) and High Pressure (HP) and at variable redox conditions. We performed HP (1-15?GPa) and HT (1600-2300°C) experiments, combined with state-of-the-art analytical techniques to better understand the behavior of H and C during planetary differentiation processes. We show that increasing pressure makes H slightly siderophile and slightly decreases the highly siderophile nature of C. This implies that the capacity of a growing core to retain significant amounts of H or C is mainly controlled by the size of the planet: small planetary bodies may retain C in their cores while H may have rather been lost in space; larger bodies may store both H and C in their cores. During the Earth's differentiation, both C and H might be sequestrated in the core. However, the H content of the core would remain one or two orders of magnitude lower than that of C since the (H/C)core ratio might range between 0.04 and 0.27.
DS201910-2246
2019
Raepsat, V.Bureau, H., Raepsat, V., Esteve, I., Armstrong, K., Manthilake, G.Replicate mantle diamonds.Goldschmidt2019, 1p. AbstractMantlediamond genesis

Abstract: Still today, diamond growth in the mantle is difficult to understand. It may implicate different processes but there is an agreement to involve fluids as diamonds parents. The composition of these fluids is supposed to be variable depending of the the settings and depths. Natural diamonds also exhibit dissolution features, possibly mantle-derived and not only due to kimberlite-induced resorption during magma ascent [1]. We present experimental results devoted to understand diamond growth versus dissolution mechanisms in the lithosphere. Experiments are performed using multianvil presses at 7 GPa, 1300-1675°C for a few hours (4 to 27 hrs). As starting materials we use mixtures of water, carbonates, natural lherzolite or MORB, graphite and diamonds seeds resulting in hydrous-carbonate-silicate fluids at high pressure and temperature. For similar pressure and temperature conditions, results show that diamonds are formed or dissolved in these fluids, depending on the redox conditions. Focussed ion beam preparations of the diamonds evidence that when they grow, they trap multi-phased inclusions similar to those observed in fibrous, coated and monocrystalline natural diamonds, in agreement with previous studies [2-4].
DS1975-0842
1978
Raeside, R.P.Raeside, R.P.A Reinvestigation of the Ile Bizard Kimberlite MontrealEos, Vol. 59, No. 4, P. 393. (abstract.).Canada, QuebecAlnoite
DS1975-0843
1978
Raeside, R.P.Raeside, R.P.A Reinvestigation of the Ile Bizard Kimberlite and its Ultramafic Xenolith Suite, Montreal.Kingston: Msc. Thesis, Queen's University, Canada, QuebecKimberlite, Alnoite
DS1982-0513
1982
Raeside, R.P.Raeside, R.P., Helmstaedt, H.The Ile Bizard Intrusion, Montreal, Quebec- Kimberlite or Lamprophyre?Canadian Journal of Earth Sciences, Vol. 19, No. 10, PP. 1996-2011.Canada, QuebecKimberlite, Xenolith, Breccia, Diatreme, Alnoite
DS1983-0528
1983
Raeside, R.P.Raeside, R.P., Helmstaedt, H.The Ile Bizard Intrusion, Montreal, Quebec- Kimberlite or Lamprophyre? Discussion.Canadian Journal of Earth Sciences, Vol. 20, No. 9, PP. 1496-1498.Canada, QuebecGenesis, Kimberlite, Alnoite
DS200812-0414
2008
Raevskii, A.B.Glaznev, V.N., Zhirova, A.M., Raevskii, A.B.New dat a on the deep structure of the Khibiny and Lovozero massifs, Kola Peninsula.Doklady Earth Sciences, Vol. 422, 1 Oct. pp. 391-393.Russia, Kola PeninsulaGeophysics
DS1996-0047
1996
Raevsky, A.Arzamastesev, A., Glaznev, V., Raevsky, A.Deep structure of Precambrian basement in the area of the Kola alkalineprovince: geophysics and petrogenesisInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 1, p. 111.Russia, Kola PeninsulaGeophysics, Tectonics
DS2000-0026
2000
Raevsky, A.B.Arazamastev, A.A., Glaznev, V.N., Raevsky, A.B., et al.Morphology and internal structure of the Kola alkaline province, northeast Fennoscandian Shield: 3D density modelingJournal of Asian Earth Science, Vol. 18, No.2, Apr. pp.213-28.Russia, Kola, FennoscandiaGeophysics - density, structure, tectonics, Kola alkaline province
DS2001-0957
2001
Raffan, N.Raffan, N.Buy side investment approach to the valuation of mining shares: a fund manager's viewValmin 01, Mineral Asset Valuation Oct. 25-6th., pp.195-200.AustraliaEconomics - cash flows, Mineral reserves, resources, valuation, exploration
DS201704-0627
2017
Raffle, K.Greig, J., Besserer, D., Raffle, K.Exploring forgotten diamond-bearing ground in the North Slave Craton. Muskox and JerichoVancouver Kimberlite Cluster, Apr. 5, 1p. AbstractCanada, NunavutDeposit - Jericho
DS200912-0607
2009
Raffone, N.Raffone, N., Chazot, G., Pin, C., Vannucci, R., Zanetti, A.Metasomatism in the lithospheric mantle beneath Middle Atlas ( Morocco) and the origin of Fe- and Mg- rich wehrlites.Journal of Petrology, Vol. 50, 2, pp. 197-249.Africa, MoroccoMetasomatism
DS1989-0522
1989
Ragan, V.M.Goebel, E.D., Coveney, R.M.Jr., Ragan, V.M.Sulfur isotopes and fluid inclusions from trace and minor occurrences of Mississippi Valley type base metals in country rocks in the mid-continentGeological Society of America (GSA) Abstract Volume, Vol. 21, No. 4, p. 12. (abstract.)Missouri, MidcontinentGeochronology
DS200412-1423
2004
Ragel Da Silva, J.M.Neves, S.P., Melo, S.C., Moura, C.A.V., Mariano, G., Ragel Da Silva, J.M.Zircon Pb Pb geochronology of the Aruaru area, northeastern Brazil: temporal constraints on the Proterozoic evolution of BorboreInternational Geology Review, Vol. 46, 1, pp. 52-63.South America, BrazilGeochronology
DS1989-1249
1989
Raghavan, V.Raghavan, V., Panchanathan, P.V.Fortran 77 utilities for lineament dat a analysisCogs Computer Contributions, Vol. 5, No. 1, pp. 1-15. Database # 18161GlobalComputer, Program - utilities Fortran 77
DS1993-1275
1993
Raghaven, V.Raghaven, V., Wadatsumi, K., Masumoto, S.Automatic extraction of lineament information from satellite images using digital eleveation dataNonrenewable Resources, Vol. 2, No. 2, Summer pp. 148-155JapanRemote sensing, Tectonics, structure
DS1994-1427
1994
Raghaven, V.Raghaven, V., et al.SMILES: a Fortran 77 program for sequential machine interpreted lineament extraction using digital imagesComputers and Geosciences, Vol. 20, No. 2, pp. 121-159GlobalComputer Program, Program -SMILES
DS200612-0484
2006
Raghubabu, K.Goutham, M.R., Raghubabu, K., Prasad, C.V.R.K., Subbarao, K.V., Reddy, V.D.A Neoproterozoic geomagnetic field reversal from the Kurnool Group, India: implications for stratigraphic correlation and formation of Gondwana.Journal of the Geological Society of India, Vol. 67, 2, pp. 221-233.Asia, IndiaGeophysics - magnetics, paleomagnetism
DS2002-0272
2002
Raghuram, H.M.Chakravarthi, V., Raghuram, H.M., Singh, S.B.3 D forward gravity modeling of basement interfaces above which density contrast varies continuously depthComputers and Geosciences, Vol.28, 2, Feb.pp. 53-7.GlobalComputers, Gravity
DS201904-0769
2019
Raghuvanshi, S.Raghuvanshi, S., Pandey, A., Pankaj, P., Chalapathi Rao, N.V., Chakrabarti, R., Pandit, D., Pandey, R.Lithosphere - asthenosphere interaction and carbonatite metasomatism in the genesis of Mesoproterozoic shoshonitic lamprophryres at Krakkodu, Wajrakarur kimberlite field, eastern Dharwar Craton, southern India.Geological Journal, doi: 10.1002/gj.3468 18p.Indiadeposit - Wajrakarur

Abstract: The spatial and temporal association between lamprophyres and kimberlites provides unique opportunities to explore their genetic relationships. This paper explores such a relationship by detailing mineralogical and geochemical aspects of Korakkodu lamprophyre dykes located within the well?known Mesoproterozoic diamondiferous Wajrakarur Kimberlite field (WKF), towards the south?western margin of Paleo-Mesoproterozoic Cuddapah Basin, Eastern Dharwar Craton, southern India. Mineralogy reveals that these dykes belong to calc?alkaline variety of lamprophyres, but their geochemistry display mixed signals of both alkaline and calc?alkaline lamprophyres. These lamprophyres are highly potassic, and their high Al2O3 and low?TiO2 content implies a shoshonitic character. Low Mg#, Ni, and Cr concentration highlight their evolved nature. High (La/Yb)N and (Gd/Yb)N content is consistent with their derivation from low degrees of partial melting, whereas highly fractionated nature suggests the presence of garnet in their source. Absence of prominent Nb?Ta anomaly implies to the dilution of lithospheric mantle source by melts rich in HFSEs and low La/Nb ratio compared to those of the calc?alkaline island arc volcanics and suggests an asthenospheric overprint on lithospheric mantle source. Carbonatite metasomatism in the source region of these lamprophyres is apparent from conspicuously high?Zr/Hf ratio, and the HFSE budget of these lamprophyres are principally controlled by the presence of phlogopite veins in their lithospheric source. An extremely heterogeneous and layered lithospheric mantle beneath Eastern Dharwar Craton has been inferred from the divergent genetic history of Mesoproterozoic lamprophyres and kimberlites in the Wajrakarur field.
DS201910-2293
2019
Raghuvanshi, S.Raghuvanshi, S., Pandey, A., Pankaj, P., Chalapathi Rao, N.V., Chakrabati, R., Pandit, D., Pandey, R.Lithosphere-asthenosphere interaction and carbonatite metasomatism in the genesis of Mesoproterozoic shoshonitic lamprophyres at Korakkodu, Wajrakarur kimberlite field, eastern Dharwar craton, southern India.Geological Journal, Vol. 54, 5, pp. 3060-3077.Indiadeposit - Wajrakarur

Abstract: The spatial and temporal association between lamprophyres and kimberlites provides unique opportunities to explore their genetic relationships. This paper explores such a relationship by detailing mineralogical and geochemical aspects of Korakkodu lamprophyre dykes located within the well?known Mesoproterozoic diamondiferous Wajrakarur Kimberlite field (WKF), towards the south?western margin of Paleo-Mesoproterozoic Cuddapah Basin, Eastern Dharwar Craton, southern India. Mineralogy reveals that these dykes belong to calc?alkaline variety of lamprophyres, but their geochemistry display mixed signals of both alkaline and calc?alkaline lamprophyres. These lamprophyres are highly potassic, and their high Al2O3 and low?TiO2 content implies a shoshonitic character. Low Mg#, Ni, and Cr concentration highlight their evolved nature. High (La/Yb)N and (Gd/Yb)N content is consistent with their derivation from low degrees of partial melting, whereas highly fractionated nature suggests the presence of garnet in their source. Absence of prominent Nb?Ta anomaly implies to the dilution of lithospheric mantle source by melts rich in HFSEs and low La/Nb ratio compared to those of the calc?alkaline island arc volcanics and suggests an asthenospheric overprint on lithospheric mantle source. Carbonatite metasomatism in the source region of these lamprophyres is apparent from conspicuously high?Zr/Hf ratio, and the HFSE budget of these lamprophyres are principally controlled by the presence of phlogopite veins in their lithospheric source. An extremely heterogeneous and layered lithospheric mantle beneath Eastern Dharwar Craton has been inferred from the divergent genetic history of Mesoproterozoic lamprophyres and kimberlites in the Wajrakarur field.
DS202008-1431
2020
Raghuvanshi, S.Pankaj, P., Giri, R.K., Chalapathi Rao, N.V., Charabarti, R., Raghuvanshi, S.Mineralogy and petrology of shoshonitic lamprophyre dykes from the Sivarampeta area, diamondiferous Wajrakarur kimberlite field, eastern Dharwar craton, southern India.Journal of Mineralogical and petrological Sciences, Vol. 115, 2, pp. 202-215. pdfIndiadeposit - Wajrakarur

Abstract: Petrology and geochemistry (including Sr and Nd isotopes) of two lamprophyre dykes, intruding the Archaean granitic gneisses at Sivarampeta in the diamondiferous Wajrakarur kimberlite field (WKF), eastern Dharwar craton, southern India, are presented. The Sivarampeta lamprophyres display porphyritic-panidiomorphic texture comprising macrocrysts/phenocrysts of olivine, clinopyroxene (augite), and mica set in a groundmass dominated by feldspar and comprising minor amounts of ilmenite, chlorite, carbonates, epidote, and sulphides. Amphibole (actinolite-tremolite) is essentially secondary in nature and derived from the alteration of clinopyroxene. Mica is compositionally biotite and occurs as a scattered phase throughout. Mineralogy suggests that these lamprophyres belong to calc-alkaline variety whereas their bulk-rock geochemistry portrays mixed signals of both alkaline as well as calc-alkaline (shoshonitic) variety of lamprophyres and suggest their derivation from the recently identified Domain II (orogenic-anorogenic transitional type mantle source) from eastern Dharwar craton. Trace element ratios imply melt-derivation from an essentially the garnet bearing-enriched lithospheric mantle source region; this is further supported by their 87Sr/86Srinitial (0.708213 and 0.708507) and ‘enriched’ ?Ndinitial (?19.1 and ?24.2) values. The calculated TDM ages (2.7-2.9 Ga) implies that such enrichment occurred prior to or during Neoarchean, contrary to that of the co-spatial and co-eval kimberlites which originated from an isotopically depleted mantle source which was metasomatized during Mesoproterozoic. The close association of calc-alkaline shoshonitic lamprophyres, sampling distinct mantle sources, viz., Domain I (e.g., Udiripikonda) and Domain II (Sivarampeta), and kimberlites in the WKF provide further evidence for highly heterogeneous nature of the sub-continental lithospheric mantle beneath the eastern Dharwar craton.
DS202201-0036
2022
Raghuvanshi, S.Raghuvanshi, S., Sharma, A., Talukdar, D., Chalapathi Rao, N.V.Chrome-diopside xenocrysts entrained in a Neoproterozoic lamprophrye dyke from the Mysuru area: their origin and implications or lithospheric thickness beneath the Western Dharwar craton, southern India.Journal of Geological Society of India, in press available 12p. PdfIndiacraton
DS202202-0211
2022
Raghuvanshi, S.Raghuvanshi, S., Chalapathi Rao, N.V., Talukdar, D., Sharma, A., Pandey, R.Chrome-diopside xenocrysts entrained in a Neoproterozoic lamprophyre dyke from the Mysuru area: their origin and implications for lithospheric thickness beneath the western Dharwar craton, southern India.Journal of the Geological Society of India, Vol.. 98, 12p. PdfIndiacraton - Dharwar

Abstract: In comparison to the eastern Dharwar Craton, the mantle-derived xenocrysts/xenoliths are extremely rare or even unreported from the western Dharwar Craton, southern India. A Neoproterozoic (ca. 800-900 Ma) lamprophyre cropping out in the Mysuru area of southern India contains chrome-diopside xenocrysts (Cr2O3 content varying from 0.2-1.23 wt%) which provide important evidence about the pressure-temperature conditions and lithospheric thickness beneath the western Dharwar Craton. Studied chrome-diopsides show compositional zoning which is lacking in the liquidus phases (amphiboles and feldspars) of the lamprophyre which additionally favors a non-cognate origin of the former. Based on the compositional zoning, all the chrome-diopside xenocrysts can be divided into three groups: (i) Group I- which are euhedral and show reverse zoning with increasing Cr-content from core to rim; (ii) Group II- which are characterized by fractures and resorption textures, show complex reverse zoning and display up to three distinct compositional layers, and (iii) Group III- which evidence the reaction of chrome-diopsides with lamprophyric melt and are marked by alteration phases, such as actinolite and chlorite, together with relicts of some unaltered xenocrysts. High Cr2O3, moderate MgO and low Al2O3 content of all the three varieties of chrome-diopside suggest them to represent disaggregated xenocrysts of mantle-derived garnet peridotite. Temperature-pressure estimates for chrome-diopside xenocrysts ranges from 895-1026 °C (± 30 °C) and 32-38 kbar respectively and correspond to depth range of 106-127 km. The study reveals that lithospheric thickness during the Neoproterozoic beneath the western Dharwar craton was at least ?115 km and is similar in composition to that of the cratonic lithosphere found in the other cratonic domains.
DS202205-0712
2022
Raghuvanshi, S.Raghuvanshi, S., Chalapthi Rao, N.V., Talukdar, D., Sharma, A., Pandey, R.Chrome-diopside xenocrysts entrained in a Neoproterozoic lamprophyre dyke from the Mysuru area: their origin and implcations for lithospheric thickness beneath the western Dharwar craton, southern India.Journal of the Geological Society of India, Vol. 98, 12p. PdfIndiachrome-diopside

Abstract: In comparison to the eastern Dharwar Craton, the mantle-derived xenocrysts/xenoliths are extremely rare or even unreported from the western Dharwar Craton, southern India. A Neoproterozoic (ca. 800-900 Ma) lamprophyre cropping out in the Mysuru area of southern India contains chrome-diopside xenocrysts (Cr2O3 content varying from 0.2-1.23 wt%) which provide important evidence about the pressure-temperature conditions and lithospheric thickness beneath the western Dharwar Craton. Studied chrome-diopsides show compositional zoning which is lacking in the liquidus phases (amphiboles and feldspars) of the lamprophyre which additionally favors a non-cognate origin of the former. Based on the compositional zoning, all the chrome-diopside xenocrysts can be divided into three groups: (i) Group I- which are euhedral and show reverse zoning with increasing Cr-content from core to rim; (ii) Group II- which are characterized by fractures and resorption textures, show complex reverse zoning and display up to three distinct compositional layers, and (iii) Group III- which evidence the reaction of chrome-diopsides with lamprophyric melt and are marked by alteration phases, such as actinolite and chlorite, together with relicts of some unaltered xenocrysts. High Cr2O3, moderate MgO and low Al2O3 content of all the three varieties of chrome-diopside suggest them to represent disaggregated xenocrysts of mantle-derived garnet peridotite. Temperature-pressure estimates for chrome-diopside xenocrysts ranges from 895-1026 °C (± 30 °C) and 32-38 kbar respectively and correspond to depth range of 106-127 km. The study reveals that lithospheric thickness during the Neoproterozoic beneath the western Dharwar craton was at least ?115 km and is similar in composition to that of the cratonic lithosphere found in the other cratonic domains.
DS1975-1025
1979
Ragland, P.C.Galipeau, J.M., Ragland, P.C.Whole Rock Chemical Constraints on the Origin of the Virginia Dale Ring Dike Complex.Geochemical Journal, Vol. 13, No. 5, NOVEMBER PP. 207-216.United States, Colorado, Wyoming, State Line, Rocky MountainsGeochemistry
DS1992-1240
1992
Ragland, P.C.Puffer, J.H., Ragland, P.C.Eastern North American Mesozoic magmatismGeological Society of America Special Paper, No. 268, 420pAppalachiaMagmatism, Table of contents
DS200512-0073
2005
Ragland, P.C.Beard, J.S., Ragland, P.C.Reactive bulk assimilation: a model for crust mantle mixing in silicic magmas.Geology, Vol. 33, 8, August pp. 681-684.MantleMelting, geothermometry
DS2000-0554
2000
Ragnarsdottir, K.Law, K.M., Blundy, J.D., Wood, B.J., Ragnarsdottir, K.Trace element partioning between wollastonite and silicate carbonate meltMineralogical Magazine, Vol. 64, No. 4, Aug. pp. 651-62.GlobalGeochemistry, Carbonatite
DS1996-0858
1996
Ragnarsdottir, K.V.Lloyd, F.E., Edgar, A.D., Ragnarsdottir, K.V.light rare earth element (LREE) distribution in perovskite, apatite and titanite from southwestUgand an xenoliths and kamafugite lavas.Mineralogy and Petrology, Vol. 57, No. 3-4, pp. 205-228.UgandaPerovskite, Rare earths, xenoliths
DS2002-1297
2002
Ragnarsson, S.Ragnarsson, S., Stefansson, R.Plume driven plumbing and crustal formation in IcelandJournal of Geophysical Research, August 10: 1029/2001JB000584IcelandTectonics, Hot spots
DS201112-1156
2011
RagozinZedgenizov, D.A., Ragozin, Shatsky, Kagi, Odake, Griffin, Araujo, YuryevaEvidence for evolution of growth media in superdeep diamonds from Sao-Luis Brazil.Goldschmidt Conference 2011, abstract p.2244.South America, BrazilCl imaging
DS200812-1048
2008
Ragozin, A.Shatsky, V., Ragozin, A., Zedgenizov, D., Mityukhin, S.Evidence for multistage evolution in a xenolith of diamond bearing eclogite from the Udachnaya kimberlite pipe.Lithos, Vol. 105, 3-4, pp. 289-300.Russia, YakutiaDeposit - Udachnaya - distribution of diamonds
DS201312-1006
2014
Ragozin, A.Zedgenizov, D.A., Kagi, H., Shatsky, V.S., Ragozin, A.Local variations of carbon isotope composition in diamonds from Sao-Luis ( Brazil): evidence for heterogenous carbon reservoir in sublithospheric mantle.Chemical Geology, Vol. 363, pp. 114-124.South America, BrazilDeposit - Sao Luis area
DS201412-0436
2014
Ragozin, A.Kagi, H., Ishibashi, H., Zedgenizov, D., Shatsky, V., Ragozin, A.Growth condition of super-deep diamonds inferred from carbon isotopic compositions and chemical compositions of nano-inclusions.Goldschmidt Conference 2014, 1p. AbstractMantleMineral chemistry
DS201412-0469
2014
Ragozin, A.Kolesnichenko, M., Zedgenizov, D., Ragozin, A., Litasov, K.Water content in olivines of mantle xenoliths from Udachnaya kimberlite pipe, Yakutia.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, YakutiaDeposit - Udachnaya
DS201603-0435
2016
Ragozin, A.Zedgenizov, D., Rubatto, D., Shatsky, V., Ragozin, A., Kalinina, V.Eclogitic diamonds from variable crustal protoliths in the northeastern Siberian Craton: trace elements and coupled Delta13C-delta 180 signatures in diamonds and garnet inclusions.Chemical Geology, Vol. 422, pp. 46-59.RussiaGeochronology
DS201808-1781
2017
Ragozin, A.Ragozin, A., Zedgenizov, D., Kuper, K., Palyanov, Y.Specific internal structure of diamonds from Zarnitsa kimberlite pipe.Crystals, Vol. 7, 5, pp. 133-Russiadeposit - Zarnitsa

Abstract: The Zarnitsa kimberlite pipe is one of the largest pipes of the Yakutian diamondiferous province. Currently, some limited published data exists on the diamonds from this deposit. Among the diamond population of this pipe there is a specific series of dark gray to black diamonds with transition morphologies between octahedron and rounded rhombic dodecahedron. These diamonds have specific zonal and sectorial mosaic-block internal structures. The inner parts of these crystals have polycrystalline structure with significant misorientations between sub-individuals. The high consistency of the mechanical admixtures (inclusions) in the diamonds cores can cause a high grid stress of the crystal structure and promote the block (polycrystalline) structure of the core components. These diamond crystals have subsequently been formed due to crystallization of bigger sub-individuals on the polycrystalline cores according to the geometric selection law.
DS201901-0059
2017
Ragozin, A.Ragozin, A., Zedgenizov, D., Kuper, K., Kalimina, V., Zemnukhov, A.The internal structure of yellow cuboid diamonds from alluvial placers of the northeastern Siberian platform.Crystals MDPI, Vol. 7, 8, 13p. Doi.org/10. 3390/cryst7080238Russiadiamond morphology

Abstract: Yellow cuboid diamonds are commonly found in diamondiferous alluvial placers of the Northeastern Siberian platform. The internal structure of these diamonds have been studied by optical microscopy, X-Ray topography (XRT) and electron backscatter diffraction (EBSD) techniques. Most of these crystals have typical resorption features and do not preserve primary growth morphology. The resorption leads to an evolution from an originally cubic shape to a rounded tetrahexahedroid. Specific fibrous or columnar internal structure of yellow cuboid diamonds has been revealed. Most of them are strongly deformed. Misorientations of the crystal lattice, found in the samples, may be caused by strains from their fibrous growth or/and post-growth plastic deformation.
DS201907-1572
2019
Ragozin, A.Shatsky, V., Jagoutz, E., Kozmenko, O., Ragozin, A., Skuzovatov, S., Sobolev, N.The protolith nature of diamondiferous metamorphic rocks of the Kokchetav Massif.Acta Geologica Sinica, Vol. 93, 1, p. 173-Russiadeposit - Kokchetav

Abstract: International Symposium on Deep Earth Exploration and Practices Beijing, China -October24-26, 2018The protolithnatureof diamondiferous metamorphic rocks of the Kokchetav MassifVladislav Shatsky1,2,3, Emil Jagoutz4, Olga Kozmenko1, Alexey Ragozin1,3, Sergei Skuzovatov2and Nikolai Sobolev1,31Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, 630090, Russia, [email protected] Institute of Geochemistry SB RAS, Irkutsk, Russia3Novosibirsk State University, Novosibirsk, Russia4Max Planck Institute for Chemistry, Mainz, GermanyUltra-high-pressure diamondiferous rocks (UHP) of the Kokchetav subduction-collision zone are considered as an idealobject for studying the mobility of elements insubduction zones of the continental type. The compositional diversity of metasedimentary rocks subjected to UHP metamorphism makes it difficult to establish the nature of their protoliths. This, in turn, complicates estimatesof the degree of depletionof the UHP metamorphic rocks relative to the protoliths.To clarify the nature of protholiths of the Kokchetav diamondiferous rocks we studied the geochemical features and Sm-Nd isotopic composition of diamondiferous calc-silicate, garnet-pyroxene rocks, high-alumina metapelitesand barren granite-gneisses.The nine samples of the Kumdy Kol mocrodiamond deposit (one granite-gneiss, 4-calc-silicate rocks, 3-garnet-pyroxenite) yielded aSm-Nd whole-rockisochronageof 1052±44 Ma. This age is close to the age of formation of the granitic gneiss basement of the Kokchetav massif (1.2-1.05 Ga) (Glorie et al., 2015). Therefore, we assume that the protoliths of these rocks were basementrocks. In this interpretation, their geochemical features may not be directly related to the processes of ultrahigh-pressure metamorphism.At the same time, the high-alumina rocks of the Barchinsky area are depleted todifferent degreeswithrespect to LREE and K yieldeda whole-rockisochron with an age of 509 ± 32 Ma, which suggests partial melting of these rocks duringthe exhumation stage.It was previously assumed that metasedimentary rocks of the Kokchetav microcontinent are the protoliths of diamondiferous rocks (Buslov et al., 2015). However, this contradicts with Sm-Nd isotopic data for metasedimentary rocks of quartzite-schist sequences of the Kokchetav microcontinent (Kovach et al., 2017). The metasedimentary rocks of the Sharyk Formation are characterized by variations in the ?Nd(t)from +4.1 to -3.3 and intNd(DM)from 1.9 to 1.25 Ga, whereasin the UHP metamorphic rocks ?Nd(t)varies from -7.6 to -13.2, and the model ages range from 2.7 to 2.3 Ga. These data clearly indicate that the metasedimentary rocks of the Kokchetav massif could not be the protolith of the ultrahigh-pressure rocks.
DS201908-1813
2019
Ragozin, A.Shatsky, V., Zedgenizov, D., Ragozin, A., Kalinina, V.Silicate melt inclusions in diamonds of eclogite paragenesis from placers on the northeastern Siberian craton.Minerals, Vol. 9, 7, pp. 412 ( 11p)Russia, Siberiadeposit - Kholomolokh

Abstract: New findings of silicate-melt inclusions in two alluvial diamonds (from the Kholomolokh placer, northeastern Siberian Platform) are reported. Both diamonds exhibit a high degree of N aggregation state (60-70% B) suggesting their long residence in the mantle. Raman spectral analysis revealed that the composite inclusions consist of clinopyroxene and silicate glass. Hopper crystals of clinopyroxene were observed using scanning electron microscopy and energy-dispersive spectroscopic analyses; these are different in composition from the omphacite inclusions that co-exist in the same diamonds. The glasses in these inclusions contain relatively high SiO2, Al2O3, Na2O and, K2O. These composite inclusions are primary melt that partially crystallised at the cooling stage. Hopper crystals of clinopyroxene imply rapid cooling rates, likely related to the uplift of crystals in the kimberlite melt. The reconstructed composition of such primary melts suggests that they were formed as the product of metasomatised mantle. One of the most likely source of melts/fluids metasomatising the mantle could be a subducted slab.
DS201910-2297
2019
Ragozin, A.Shatsky, V., Ragozin, A., Logvinova, A., Wirth, R., Sobolev, N.Alluvial diamonds from iron-saturated mantle beneath the northeastern margin of Siberian craton.Goldschmidt2019, 1p. AbstractRussiacraton

Abstract: Diamonds of eclogitic paragenesis are dominant in the placer deposits in the northeastern part of the Siberian Craton. Multiple inclusions and host diamonds carbon isotopes composition are consistent with a mixing model in which they result from the interaction of slab-derived melt/fluid with surrounding mantle [1,2]. A significant portion of diamonds contains black inclusions usually interpreted as graphite or sulphides. Twenty six dark inclusions from the 22 diamonds were exposed by polishing for chemical microanalysis. Inclusions were studied with SEM, TEM and EMP. Fe-C-O melt inclusions in association with with Kfsp, Ol and silicate melt inclusions were identified. Most of the inclusions are heterogeneous in composition and consist of iron carbides, iron in various oxidation states and carbon. Carbides contain impurities of Ni (0-0.6%), Sr (up to 3.4%), Cr (up to 0.8%) Si (up to 1%). Inclusions of wustite and Fe-Ti-O melt were identified in one diamond along with inclusions of Fe-C-O melt. In two cases diamond inclusions found within host diamond crystal. Diamond inclusions are surronded by a border consisting of wustite and siderite. Inclusions of Fe-C-O melt in allivial diamonds are best explained by carbonate melt-iron reaction [3].
DS201911-2556
2019
Ragozin, A.Ragozin, A., Zedgenizov, D., Kagi, H., Kuper, K.E., Shatsky, V.Deformation features of superdeep diamonds.Goldschmidt2019, 1p. AbstractSouth America, Brazil, Russia, Siberiadeposit - Juina

Abstract: Much of our knowledge of the Earth’s deep interior comes from theoretical models, which are based on the results of experimental petrology and seismology. Diamonds in such models are the unique natural samples because they contain and preserve inclusions of mantle materials that have been entrapped during diamond growth and remained unchanged for long geologic time. In the present study for superdeep sublithospheric diamonds from Saõ-Luiz (Juina, Brazil) and northeastern Siberian Platform with mineral inclusions of the Transition Zone and Lower Mantle (majorite garnet, coesite (stishovite), ferropericlase and Mg-Si-, Ca-Si-, Ca-Ti, Ca-Si- Ti-perovskite), the diffraction of backscattered electrons technique (EBSD) revealed features of the internal structure. Superdeep diamonds are characterized by a defective and imperfect internal structure, which is associated with the processes of growth and post-growth plastic deformation. The deformation is manifested both in the form of stripes parallel to the (111) direction, and in the form of an unordered disorientation of crystal blocks up to 2°. In addition, for many crystals, a block structure was established with a greater disorientation of the sub-individuals, as well as the presence of “diamond-in-diamond” inclusions and microtwins. Additional stresses are often observed around inclusions associated with the high remaining internal pressure. It has previously been shown that the crystal structure of superdeep diamonds is significantly deformed around inclusions of perovskites, SiO2 (stishovite?), and Mg2SiO4 (ringwoodite?). The significant plastic deformations detected by the EBSD around inclusions testify to phase transitions in superdeep minerals (perovskites, stishovite, and ringwoodite) [1].
DS202004-0549
2020
Ragozin, A.Zedgenizov, D., Bogush, I., Shatsky, V., Kovalchuk, O., Ragozin, A., Kalinina, V.Mixed habit type Ib-IaA diamond from an Udachnaya eclogite.Minerals MDPI, Vol. 9, 9120741, 12p. PdfRussiadeposit - Udachnaya

Abstract: The variety of morphology and properties of natural diamonds reflects variations in the conditions of their formation in different mantle environments. This study presents new data on the distribution of impurity centers in diamond type Ib-IaA from xenolith of bimineral eclogite from the Udachnaya kimberlite pipe. The high content of non-aggregated nitrogen C defects in the studied diamonds indicates their formation shortly before the stage of transportation to the surface by the kimberlite melt. The observed sectorial heterogeneity of the distribution of C- and A-defects indicates that aggregation of nitrogen in the octahedral sectors occurs faster than in the cuboid sectors.
DS202006-0937
2020
Ragozin, A.Mikhailenko, D., Golovin, A., Korsakov, A., Aulbach, S., Gerdes, A., Ragozin, A.Metasomatic evolution of coesite-bearing diamondiferous eclogite from the Udachnaya kimberlite.Minerals, Vol. 10, 4, 24p. PdfRussia, Siberiadeposit - Udachnaya

Abstract: A coesite-bearing diamondiferous eclogite from the Udachnaya kimberlite (Daldyn field, Siberian craton) has been studied to trace its complex evolution recorded in rock-forming and minor mineral constituents. The eclogite sample is composed of rock-forming omphacite (60 vol%), garnet (35 vol%) and quartz/coesite (5 vol%) and contains intergranular euhedral zoned olivine crystals, up to 200 µm long, coexisting with phlogopite, orthopyroxene, clinopyroxene (secondary), K-feldspar, plagioclase, spinel, sodalite and djerfisherite. Garnet grains are zoned, with a relatively homogeneous core and a more magnesian overgrowth rim. The rim zones further differ from the core in having higher Zr/Y (6 times that in the cores), ascribed to interaction with, or precipitation from, a kimberlite-related melt. Judging by pressure-temperature estimates (~1200 °C; 6.2 GPa), the xenolith originated at depths of ~180-200 km at the base of the continental lithosphere. The spatial coexistence of olivine, orthopyroxene and coesite/quartz with K-Na-Cl minerals in the xenolith indicates that eclogite reacted with a deep-seated kimberlite melt. However, Fe-rich olivine, orthopyroxene and low-pressure minerals (sodalite and djerfisherite) likely result from metasomatic reaction at shallower depths during transport of the eclogite by the erupting kimberlite melt. Our results demonstrate that a mixed eclogitic-peridotitic paragenesis, reported previously from inclusions in diamond, can form by interaction of eclogite and a kimberlite-related melt.
DS202012-2256
2020
Ragozin, A.:.Zedgenizov, D.A., Skuzovatov, S.Y., Griffin, W.L., Pomazansky, B.S., Ragozin, A.:., Kalinina, V.V.Diamond forming HDFs tracking episodic mantle metasomatism beneath Nyurbinskaya kimberlite pipe (Siberian craton).Contributions to Mineralogy and Petrology, Vol. 175, 106, 21p. PdfRussiadeposit - Nyurbinskaya

Abstract: We present a new dataset on the composition of high-density fluids (HDFs) in cloudy (n?=?25), coated (n?=?10) and cuboid (n?=?10) diamonds from the Nyurbinskaya kimberlite pipe. These diamonds represent different populations each showing distinct growth histories. The cores of coated diamonds display multiple growth stages and contrasting sources of carbon. Fibrous coats and cuboid diamonds have similar carbon isotopes and nitrogen systematics, suggesting their formation in the last metasomatic events related to kimberlite magmatism, as is common for most such diamonds worldwide. The HDFs in most of these diamonds span a wide range from low-Mg carbonatitic to hydrous silicic compositions. The major- and trace-element variations suggest that the sources for such HDFs range in composition between the depleted mantle and more fertile mantle reservoirs. Hydrous-silicic HDFs could originate from a 13C-enriched source, which originates through subduction of crustal metasedimentary material. Percolation of such HDFs through carbonated eclogites and peridotites facilitates the formation of cuboid diamonds and fibrous coats in the mantle section beneath the corresponding area of the Siberian craton. Cloudy diamonds represent an apparently older population, reflecting continuous diamond formation predominantly from high-Mg carbonatitic HDFs that caused discrete episodes of diamond precipitation. Their high Mg# and enrichment in incompatible elements support a metasomatized peridotitic source for these HDFs.
DS200812-1122
2008
Ragozin, A.A.L.A.Stepanov, A.A.S.A., Shatsky, V.A.S.A., Zedgenisov, D.A.A.A., Ragozin, A.A.L.A.Chemical heterogeneity in the Diamondiferous eclogite xenolith from the Udachanya pipe.Doklady Earth Sciences, Vol. 419, 2, pp. 308-311.RussiaPetrology - Udachnaya
DS200812-1123
2008
Ragozin, A.A.L.A.Stepanov, A.A.S.A., Shatsky, V.A.S.A., Zedgenizov, D.A.A.A., Ragozin, A.A.L.A.Chemical heterogenity in the Diamondiferous eclogite xenolith from the Udachnaya kimberlite pipe.Doklady Earth Sciences, Vol. 419, 1, pp. 308-311.RussiaGeochemistry - Udachnaya
DS202109-1486
2021
Ragozin, A.I.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.
DS200612-1272
2006
Ragozin, A.J.Shatsky, V.S., Ragozin, A.J., Sobolev, N.V.Some aspects of metamorphic evolution of ultrahigh pressure calc-silicate rocks.Russian Geology and Geophysics, Vol. 47, 1 pp. 105-119.MantleUHP
DS2002-1298
2002
Ragozin, A.L.Ragozin, A.L., Shatsky, V.S., Tylov, G.M., Goryainov, S.V.Coesite inclusions in rounded diamonds from placers of the northeastern Siberian Platform.Doklady, Vol.384,4, May-June, pp. 385-9.Russia, SiberiaAlluvials, Diamond - inclusions, coesite
DS200512-0968
2005
Ragozin, A.L.Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L., Mityukhin, S.I., Sobolev, N.V.Evidence for metasomatic formation of diamond in eclogite xenolith from the Udachnaya kimberlite pipe.Doklady Earth Sciences, Vol. 402, 4, pp. 587-90.Russia, YakutiaMetasomatism
DS200612-1121
2006
Ragozin, A.L.Ragozin, A.L., Shatsky, V.S., Zetgenizov, D.A., Mityukhin, S.I.Evidence for evolution of diamond crystallization medium in eclogite xenolith from the Udachnaya kimberlite pipe, Yakutia.Doklady Earth Sciences, Vol. 407A, 3, pp. 465-468.Russia, YakutiaDiamond morphology - Udachnaya
DS200612-1274
2006
Ragozin, A.L.Shatsky, V.S., Stepanov, A.S., Zedgenizov, D.A., Ragozin, A.L.Mineral inclusions in diamonds from chemically heterogeneous eclogite xenolith.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 25. abstract only.RussiaDiamond inclusions
DS200612-1275
2006
Ragozin, A.L.Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L.Evidence of mantle modification in Diamondiferous eclogite xenolith from Udachnaya kimberlite pipe, Yakutia.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 25. abstract only.Russia, YakutiaDeposit - Udachnaya, metasomatism
DS200712-0585
2007
Ragozin, A.L.Kuper, K.E., Zedgenizov, D.A., Ragozin, A.L., Shatsky, V.S., Porosev, V.V., Zolotarev, K.V., Baibchev, IvanovThree dimensional distribution of minerals in Diamondiferous eclogites, obtained by the method of high resolution X-ray computed tomography.Nuclear Instruments and Methods in Physics Research Section A., Vol. 575, 1-2, pp. 255-258.TechnologyDiamond genesis
DS200712-1218
2007
Ragozin, A.L.Zedgenizov, D.A., Ragozin, A.L., Shatsky, V.S.Chloride carbonate fluid in diamonds from the eclogite xenolith.Doklady Earth Sciences, Vol. 445, 6, pp. DOI:10.1134/S1028334 X07060293Russia, YakutiaGeochemistry
DS200912-0849
2009
Ragozin, A.L.Zedgenizov, D.A., Ragozin, A.L., Shjatsky, V.S., Araujo, D., Griffin, W.L., Kagi, H.Mg and Fe rich carbonate silicate high density fluids in cuboid diamonds from the Internationalnaya kimberlite pipe. Yakutia.Lithos, In press availableRussia, YakutiaDeposit - International
DS201012-0607
2009
Ragozin, A.L.Ragozin, A.L., Shatskii, V.S., Zedgenizov, D.A.New dat a on the growth environment of diamonds of the variety V from placers of the northeastern Siberian platform.Doklady Earth Sciences, Vol. 425, 2, April pp. 436-440.Russia, SiberiaAlluvials
DS201012-0691
2010
Ragozin, A.L.Shatskii, V.S., Zedgenizov, D.A., Ragozin, A.L.Majoritic garnets in diamonds from placers of the northeastern Siberian Platform.Doklady Earth Sciences, Vol. 432, 2, pp. 839-845.RussiaAlluvials
DS201012-0702
2010
Ragozin, A.L.Shiryaev, A.A., Safonov, O.G., Ragozin, A.L.XANES spectroscopy at the potassium K edge of inclusions in kimberlitic diamonds.International Mineralogical Association meeting August Budapest, abstract p. 186.Russia, South America, BrazilSpectroscopy
DS201112-0944
2011
Ragozin, A.L.Shatski, V.S., Zedgenizov, D.A., Ragozin, A.L., Kalinina, V.V., Reutskii, V.N.Local variations in carbon isotopes and nitrogen contents in diamonds from placers of the northeastern portion of the Siberian Platform.Doklady Earth Sciences, Vol. 440, 1, pp.Russia, SiberiaGeochronology
DS201112-0973
2011
Ragozin, A.L.Skuzovatov, S.Yu., Zedgenizov, D.A., Shatsky, V.S., Ragozin, A.L., Kuper, K.E.Composition of cloudy Micro inclusions in octahedral diamonds from the Internatsional'naya kimberlite pipe ( Yakutia).Russian Geology and Geophysics, Vol. 52, pp. 85-96.Russia, YakutiaDiamond morphology, inclusions
DS201212-0507
2012
Ragozin, A.L.Nadolinny, V.A., Yuryeva,O.P., Rakhmanova, M.I., Shatsky, V.S., Palyanov, Y.N., Kupriyanov, I.N., Zedgenizov, D.A., Ragozin, A.L.Distribution of OK1, N3 and NU1 defects in diamond crystals of different habits.European Journal of Mineralogy, Vol. 24, 4, pp. 645-650.TechnologyDiamond morphology
DS201212-0670
2012
Ragozin, A.L.Smelov, A.P., Shatsky, V.S., Ragozin, A.L., Reutskii, V.N., Molotkov, A.E.Diamondiferous Archean rocks of the Olondo greenstone belt ( western Aldan-Stanovoy shield).Russian Geology and Geophysics, Vol. 53, pp. 1012-1022.RussiaDiamond - genesis
DS201312-0729
2013
Ragozin, A.L.Ragozin, A.L., Shatsky, V.S., Zedgenizov, D.A., Griffin, W.L.Growth medium and carbon source of unusual rounded diamonds from alluvial placers of the north-east of Siberian platform.Goldschmidt 2013, AbstractRussia, SiberiaPlacers, alluvials
DS201312-0805
2013
Ragozin, A.L.Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L.Evidence for formation of alluvial diamonds from north-east of Siberian platform in subduction environment.Goldschmidt 2013, 1p. AbstractRussiaAlluvials
DS201312-0831
2012
Ragozin, A.L.Skuzovatov, S.Yu., Zedgenizov, D.A., Ragozin, A.L., Shatsky, V.S.Growth medium composition of coated diamonds from the Sytykanskaya kimberlite pipe ( Yakutia).Russian Geology and Geophysics, Vol. 53, 11, pp. 1197-1208.RussiaDeposit - Sytykanskaya
DS201312-0834
2012
Ragozin, A.L.Smelov, A.P., Shatsky, V.S., Ragozin, A.L., Reutskii, V.N., Molotkov, A.E.Diamondiferous Archean rocks of the Olondo greenstone belt ( western Aldan-Stanovoy shield).Russian Geology and Geophysics, Vol. 53, pp. 1012-1022.RussiaDiamond morphology
DS201312-1007
2013
Ragozin, A.L.Zedgenizov, D.A., Ragozin, A.L., Shatsky, V.S., Griffin, W.L.Parental growth media of Siberian diamonds - relation to kimberlites.Goldschmidt 2013, 1p. AbstractRussiaDiamond morphology
DS201412-0718
2014
Ragozin, A.L.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
DS201412-0801
2014
Ragozin, A.L.Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L., Kalinina, V.V.Carbon isotopes and nitrogen contents in placer diamonds from the NE Siberian craton: implications for diamond origins.European Journal of Mineralogy, Vol. 26, 1, pp. 41-52.RussiaAlluvials
DS201412-0802
2015
Ragozin, A.L.Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L., Kalinina, V.V.Diamondiferous subcontinental lithospheric mantle of the northeastern Siberian craton: evidence from mineral inclusions in alluvial diamonds.Gondwana Research, Vol. 28, 1, pp. 106-120.Russia, SiberiaMineral inclusions
DS201412-1023
2014
Ragozin, A.L.Zedgenizov, D.A., Shatskiy, A., Ragozin, A.L., Kagi, H., Shatsky, V.S.Merwinite in diamond from Sao Luiz, Brazil: a new mineral of the Ca-rich mantle environment.American Mineralogist, Vol. 99, pp. 547-550.South America, BrazilMineralogy
DS201502-0128
2015
Ragozin, A.L.Zedgenizov, D.A., Shatsky, V.S., Panin, A.V., Evtushenko, O.V., Ragozin, A.L., Kagi, H.Evidence for phase transitions in mineral inclusions in superdeep diamonds of the Sao Luiz deposit, Brazil.Russian Geology and Geophysics, Vol. 56, 1, pp. 296-305.South America, BrazilDeposit - Sao Luiz
DS201507-0335
2015
Ragozin, A.L.Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L., Kalinina, V.V.Diamondiferous subcontinental lithospheric mantle of the northeastern Siberian Craton: evidence from mineral inclusions in alluvial diamonds. Kapchan Fold Belt Olenek ProvinceGondwana Research, Vol. 28, 1, pp. 106-120.RussiaDiamond - inclusions
DS201509-0427
2015
Ragozin, A.L.Shatsky, V.S., Skuzovatov, S.Yu., Ragozin, A.L., Sobolev, N.V.Mobility of elements in a continental subduction zone: evidence from the UHP metamorphic complex of the Kokchetav massif.Russian Geology and Geophysics, Vol. 56, pp. 1016-1034.RussiaKokchetav massif

Abstract: We studied clastics of high-alumina garnet-kyanite-mica schists and garnet-kyanite-quartz granofelses, including diamond-bearing ones, found in the eluvial sediments near Lake Barchi. In contents of major elements the studied rocks correspond to argillaceous shales. The garnet-kyanite-quartz granofelses are poorer in K (0.49-1.35 wt.% K2O) than the garnet-kyanite-mica schists (4.9-2.2 wt.% K2O) but have the same contents of other major components. The REE patterns of most of the garnet-kyanite-phengite schists are similar to those of the Post-Archean Australian Shale (PAAS) (xLa/Yb = 13). All garnet-kyanite-quartz rocks are much stronger depleted in LREE (xLa/Yb = 1.4) and other incompatible elements. Our studies show that allanite and monazite are the main concentrators of LREE and Th in the garnet-kyanite-phengite rocks of the Barchi site. Monazite, occurring as inclusions in garnet, contains not only LREE but also Th, U, and Pb. Rutile of the nondepleted rocks is enriched in Fe and Nb impurities only. The garnet-kyanite-quartz granofelses bear rutile, apatite, and xenotime as accessory phases. Rutile of the depleted rocks shows wide variations in contents of Nb, Ta, and V impurities. In places, the contents of Nb and Ta reach 10.5 and 2.3 wt.%, respectively. The rutile decomposes into rutile with Nb (1.4 wt.%) and Fe (0.87 wt.%) impurities and titanium oxide rich in Fe (6.61 wt.%), Nb (up to 20.8 wt.%), and Ta (up to 2.81%) impurities. Based on the measured contents of incompatible elements in differently depleted high-alumina rocks, the following series of element mobility during UHP metamorphism has been established: Th > Ce > La > Pr > Nd > K > Ba > Rb > Cs > Sm > Eu. The contents of U, P, and Zr in the depleted rocks are similar to those in the nondepleted rocks. The studies have shown that metapelites subducted to the depths with diamond stability conditions can be depleted to different degrees. This might be either due to their exhumation from different depths of the subduction zone or to the presence of an external source of water controlling the temperature of dissolution of phengite and the formation of supercritical fluid/melt.
DS201610-1902
2016
Ragozin, A.L.Ragozin, A.L., Zedgenizov, D.A., Kuper, K.E., Shatsky, V.S.Radial mosaic internal structure of rounded diamond crystals from alluvial placers of Siberian platform. EbayakMineralogy and Petrology, in press available 15p.RussiaX-ray topography

Abstract: The specific gray to almost black diamonds of rounded morphology are especially typical in alluvial placers of the northeastern part of the Siberian platform. The results of study of internal structure of these diamonds are presented. X-ray topography and birefringence patterns of polished plates of studied diamonds show their radial mosaic structure. Diamonds consists of slightly misorientated (up to 20?) subindividuals which are combined to mosaic wedge-shaped sectors. Electron back-scatter diffraction technique has demonstrated that subindividuals are often combined in the single large blocks (subgrains). The whole crystals commonly consist of several large subgrains misoriented up to 5° to one another. The total nitrogen content of these diamonds vary in the range 900-3300 ppm and nitrogen aggregation state (NB/(NB + NA)*100) from 25 to 64 %. Rounded diamond crystals of variety V are suggested to have been formed at the high growth rate caused by the high oversaturation of carbon in the crystallization medium. It may result in the splitting of growing crystal and their radial mosaic structure as a sequence. High content of structural nitrogen defects and the great number of mechanical impurities - various mineral and fluid inclusions may also favor to generation of this structure.
DS201610-1909
2016
Ragozin, A.L.Sobolev, N.V., Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L., Reutsky, V.N.Polycrystalline diamond aggregates from the Mir kimberlite pipe, Yakutia: evidence for mantle metasomatism.Lithos, in press available 10p.RussiaDeposit - Mir

Abstract: Polycrystalline diamond aggregates (boart, framesites, diamondites) have been widely studied but their origin is poorly understood. We report the results of a study in situ of two polished fragments of fine-grained (40-400 ?m size of individual diamond grains) dense polycrystalline diamond aggregates from the Mir pipe containing visible multiple interstitial garnet inclusions. They were analyzed for major and trace elements of inclusions and one of them — for ?13C and N abundance and isotopic composition of host diamonds. These aggregates are classified as variety IX by Orlov (1977). No cavities were observed in these samples. Sixty two irregular garnet grains and one clinopyroxene inclusion were detected and analyzed in sample Mr 832. Garnets are homogeneous within single grains but variable in Mg# [100Mg/(Mg + Fe)] from 60 up to 87 and CaO contents (3.3-5.3 wt.%) among grains with a trend to negative correlation. Low Cr (550-640 ppm) confirms eclogitic (E-type) paragenesis. High Na2O contents (5.2 wt.%) of a single pyroxene inclusion are additional evidence of eclogitic nature of this sample. Wide variations in trace elements (ppm) are characteristic for garnet grains: Sr (2.7-25.6), Y (9.7-14.1), Zr (15.6-38.7) and positive Eu anomaly is present. The ?13C of diamonds within studied sample is variable (? 6.4 ÷? 9.8 ‰) as well as N abundance (75-1150 ppm) and ?15N ? 27, ? 38, ? 58 ‰. The second peridotitic (U/P-type) sample Mr 838 contains eight inclusions of Mg-rich Cr-pyropes (Mg# ~ 85, Cr2O3 3.2-3.4 wt.%) and magnesite inclusion with 4.35 wt.% FeO and 1.73 wt.% CaO. Trace element content in pyropes is relatively uniform (ppm): Sr (0.4-1.6), Y (13.2-13.4) and Zr (13.0). We conclude that heterogeneous distribution of the trace elements among garnet grains in Mr 832 and magnesite presence in Mr 838 are indicative of the effects of mantle metasomatism and rapid crystallization shortly before the eruption of the kimberlite.
DS201612-2327
2016
Ragozin, A.L.Ragozin, A.L., Palyanov, Yu.N., Zedgenizov, D.A., Kalinin, A.A., Shatsky, V.S.Homogenization of carbonate bearing Micro inclusions in diamond at P-T parameters of the upper mantle.Doklady Earth Sciences, Vol. 470, 2, pp. 1059-1062.RussiaDeposit - Internationalskaya

Abstract: The staged high-pressure annealing of natural cubic diamonds with numerous melt microinclusions from the Internatsional’naya kimberlite pipe was studied experimentally. The results mainly show that the carbonate phases, the daughter phases in partially crystallized microinclusions in diamonds, may undergo phase transformations under the mantle P-T conditions. Most likely, partial melting and further dissolution of dolomite in the carbonate-silicate melt (homogenization of inclusions) occur in inclusions. The experimental data on the staged high-pressure annealing of diamonds with melt microinclusions allow us to estimate the temperature of their homogenization as 1400-1500°C. Thus, cubic diamonds from the Internatsional’naya pipe could have been formed under quite high temperatures corresponding to the lithosphere/asthenosphere boundary. However, it should be noted that the effect of selective capture of inclusions with partial loss of volatiles in relation to the composition of the crystallization medium is not excluded during the growth. This may increase the temperature of their homogenization significantly between 1400 and 1500°C.
DS201702-0222
2017
Ragozin, A.L.Kolesnichenko, M.V., Zedgenizov, D.A., Litasov, K.D., Safonova, I.Y., Ragozin, A.L.Heterogenesous distribution of water in the mantle beneath the central Siberian Craton: implications for Udachnaya kimberlite pipe.Gondwana Research, in press available 18p.RussiaDeposit - Udachnaya

Abstract: The paper presents new petrographic, major element and Fourier transform infrared (FTIR) spectroscopy data and PT-estimates of whole-rock samples and minerals of a collection of 19 relatively fresh peridotite xenoliths from the Udachnaya kimberlite pipe, which were recovered from its deeper levels. The xenoliths are non-deformed (granular), medium-deformed and highly deformed (porphyroclastic, mosaic-porphyroclastic, mylonitic) lherzolites, harzburgite and dunite. The lherzolites yielded equilibration temperatures (T) and pressures (P) ranging from 913 to 1324 °C and from 4.6 to 6.3 GPa, respectively. The non-deformed and medium-deformed peridotites match the 35 mW/m2 conductive continental geotherm, whereas the highly deformed varieties match the 45 mW/m2 geotherm. The content of water spans 2 ± 1-95 ± 52 ppm in olivine, 1 ± 0.5-61 ± 9 ppm in orthopyroxene, and 7 ± 2-71 ± 30 ppm in clinopyroxene. The amount of water in garnets is negligible. Based on the modal proportions of mineral phases in the xenoliths, the water contents in peridotites were estimated to vary over a wide range from < 1 to 64 ppm. The amount of water in the mantle xenoliths is well correlated with the deformation degree: highly deformed peridotites show highest water contents (64 ppm) and those medium-deformed and non-deformed contain ca. 1 ppm of H2O. The high water contents in the deformed peridotites could be linked to metasomatism of relatively dry diamondiferous cratonic roots by hydrous and carbonatitic agents (fluids/melts), which may cause hydration and carbonation of peridotite and oxidation and dissolution of diamonds. The heterogeneous distribution of water in the cratonic mantle beneath the Udachnaya pipe is consistent with the models of mantle plume or veined mantle structures proposed based on a trace element study of similar xenolithic suits. Mantle metasomatism beneath the Siberian Craton and its triggered kimberlite magmatism could be induced by mantle enrichment in volatiles (H2O, CO2) supplied by numerous subduction zones which surrounded the Siberian continent in Neoproterozoic-Cambrian time.
DS201706-1086
2017
Ragozin, A.L.Kolesnichenko, M.V., Zedgenizov, D.A., Litasov, K.D., Safonova, I.Y., Ragozin, A.L.Heterogeneous distribution of water in the mantle beneath the central Siberian craton: implications from the Udachachnaya kimberlite pipe.Gondwana Research, Vol. 47, pp. 249-266.Russiadeposit - Udachnaya

Abstract: The paper presents new petrographic, major element and Fourier transform infrared (FTIR) spectroscopy data and PT-estimates of whole-rock samples and minerals of a collection of 19 relatively fresh peridotite xenoliths from the Udachnaya kimberlite pipe, which were recovered from its deeper levels. The xenoliths are non-deformed (granular), medium-deformed and highly deformed (porphyroclastic, mosaic-porphyroclastic, mylonitic) lherzolites, harzburgite and dunite. The lherzolites yielded equilibration temperatures (T) and pressures (P) ranging from 913 to 1324 °C and from 4.6 to 6.3 GPa, respectively. The non-deformed and medium-deformed peridotites match the 35 mW/m2 conductive continental geotherm, whereas the highly deformed varieties match the 45 mW/m2 geotherm. The content of water spans 2 ± 1-95 ± 52 ppm in olivine, 1 ± 0.5-61 ± 9 ppm in orthopyroxene, and 7 ± 2-71 ± 30 ppm in clinopyroxene. The amount of water in garnets is negligible. Based on the modal proportions of mineral phases in the xenoliths, the water contents in peridotites were estimated to vary over a wide range from < 1 to 64 ppm. The amount of water in the mantle xenoliths is well correlated with the deformation degree: highly deformed peridotites show highest water contents (64 ppm) and those medium-deformed and non-deformed contain ca. 1 ppm of H2O. The high water contents in the deformed peridotites could be linked to metasomatism of relatively dry diamondiferous cratonic roots by hydrous and carbonatitic agents (fluids/melts), which may cause hydration and carbonation of peridotite and oxidation and dissolution of diamonds. The heterogeneous distribution of water in the cratonic mantle beneath the Udachnaya pipe is consistent with the models of mantle plume or veined mantle structures proposed based on a trace element study of similar xenolithic suits. Mantle metasomatism beneath the Siberian Craton and its triggered kimberlite magmatism could be induced by mantle enrichment in volatiles (H2O, CO2) supplied by numerous subduction zones which surrounded the Siberian continent in Neoproterozoic-Cambrian time.
DS201801-0060
2018
Ragozin, A.L.Shatsky, V.S., Malkovets, V.G., Belousova, E.A., Tretiakova, I.G., Griffin, W.L., Ragozin, A.L., Wang, Q., Gibsher, A.A., O'Reilly, S.Y.Multi-stage modification of Paleoarchean crust beneath the Anabar tectonic province ( Siberian craton).Precambrian Research, Vol. 305, pp. 125-144.Russiacraton - Siberian

Abstract: According to present views, the crustal terranes of the Anabar province of the Siberian craton were initially independent blocks, separated from the convecting mantle at 3.1 (Daldyn terrane), 2.9 (Magan terrane) and 2.5?Ga (Markha terrane) (Rosen, 2003, 2004; Rosen et al., 1994, 2005, 2009). Previous studies of zircons in a suite of crustal xenoliths from kimberlite pipes of the Markha terrane concluded that the evolution of the crust of the Markha terrane is very similar to that of the Daldyn terrane. To test this conclusion we present results of U-Pb and Hf-isotope studies on zircons in crustal xenoliths from the Zapolyarnaya kimberlite pipe (Upper Muna kimberlite field), located within the Daldyn terrane, and the Botuobinskaya pipe (Nakyn kimberlite field) in the center of the Markha terrane. The data on xenoliths from the Botuobinskaya kimberlite pipe record tectonothermal events at 2.94, 2.8, 2.7 and 2?Ga. The event at 2?Ga caused Pb loss in zircons from a mafic granulite. U-Pb dating of zircons from the Zapolyarnaya pipe gives an age of 2.7?Ga. All zircons from the studied crustal xenoliths have Archean Hf model ages ranging from 3.65 to 3.11?Ga. This relatively narrow range suggests that reworking of the ancient crust beneath the Nakyn and Upper Muna kimberlite fields was minor, compared with the Daldyn and Alakit-Markha fields (Shatsky et al., 2016). This study, when combined with dating of detrital zircons, implies that tectonic-thermal events at 2.9-2.85, 2.75-2.7 and 2.0-1.95?Ga occurred everywhere on the Anabar tectonic province, and could reflect the upwelling of superplumes at 2.9, 2.7 and 2?Ga. The presence of the same tectonic-thermal events in the Daldyn and Markha terranes (Rosen et al., 2006a,b) supports the conclusion that the identification of the Markha terrane as a separate unit is not valid.
DS201806-1241
2018
Ragozin, A.L.Ragozin, A.L., Zedgenizov, D.A., Shatsky, V.S., Kuper, K.E.Formation of mosaic diamonds from the Zarnitsa kimberlite.Russian Geology and Geophysics, Vol. 59, pp. 486-498.Russiadeposit - Zarnitsa

Abstract: Mosaic diamonds from the Zarnitsa kimberlite (Daldyn field, Yakutian diamondiferous province) are morphologicaly and structurally similar to dark gray mosaic diamonds of varieties V and VII found frequently in placers of the northeastern Siberian craton. However, although being similar in microstructure, the two groups of diamonds differ in formation mechanism: splitting of crystals in the case of placer diamonds (V and VII) and growth by geometric selection in the Zarnitsa kimberlite diamonds. Selective growth on originally polycrystalline substrates in the latter has produced radial micro structures with grains coarsening rimward from distinctly polycrystalline cores. Besides the formation mechanisms, diamonds of the two groups differ in origin of mineral inclusions, distribution of defects and nitrogen impurity, and carbon isotope composition. Unlike the placer diamonds of varieties V and VII, the analyzed crystals from the Zarnitsa kimberlite enclose peridotitic minerals (olivines and subcalcic Cr-bearing pyropes) and have total nitrogen contents common to natural kimberlitic diamonds (0 to 1761 ppm) and typical mantle carbon isotope compositions (-1.9 to -6.2%c 513C; -4.2%c on average). The distribution of defect centers in the Zarnitsa diamond samples fits the annealing model implying that nitrogen aggregation decreases from core to rim.
DS201808-1788
2018
Ragozin, A.L.Shatsky, V.S., Malkovets, V.G., Belousova, E.A., Tretiakova, I.G., Griffin, W.L., Ragozin, A.L., Wang, Q., Gibsher, A.A., O'Reilly, S.Y.Multi stage modification of Paleoarchean crust beneath the Anabar tectonic provnce ( Siberian craton).Precambrian Research, Vol. 305, pp. 125-144.Russiatectonics

Abstract: According to present views, the crustal terranes of the Anabar province of the Siberian craton were initially independent blocks, separated from the convecting mantle at 3.1 (Daldyn terrane), 2.9 (Magan terrane) and 2.5?Ga (Markha terrane) (Rosen, 2003, 2004; Rosen et al., 1994, 2005, 2009). Previous studies of zircons in a suite of crustal xenoliths from kimberlite pipes of the Markha terrane concluded that the evolution of the crust of the Markha terrane is very similar to that of the Daldyn terrane. To test this conclusion we present results of U-Pb and Hf-isotope studies on zircons in crustal xenoliths from the Zapolyarnaya kimberlite pipe (Upper Muna kimberlite field), located within the Daldyn terrane, and the Botuobinskaya pipe (Nakyn kimberlite field) in the center of the Markha terrane. The data on xenoliths from the Botuobinskaya kimberlite pipe record tectonothermal events at 2.94, 2.8, 2.7 and 2?Ga. The event at 2?Ga caused Pb loss in zircons from a mafic granulite. U-Pb dating of zircons from the Zapolyarnaya pipe gives an age of 2.7?Ga. All zircons from the studied crustal xenoliths have Archean Hf model ages ranging from 3.65 to 3.11?Ga. This relatively narrow range suggests that reworking of the ancient crust beneath the Nakyn and Upper Muna kimberlite fields was minor, compared with the Daldyn and Alakit-Markha fields (Shatsky et al., 2016). This study, when combined with dating of detrital zircons, implies that tectonic-thermal events at 2.9 -2.85, 2.75 -2.7 and 2.0 -1.95?Ga occurred everywhere on the Anabar tectonic province, and could reflect the upwelling of superplumes at 2.9, 2.7 and 2?Ga. The presence of the same tectonic-thermal events in the Daldyn and Markha terranes (Rosen et al., 2006a,b) supports the conclusion that the identification of the Markha terrane as a separate unit is not valid.
DS201810-2339
2018
Ragozin, A.L.Kolesnichenko, M.V., Zedgenizov, D.A., Ragozin, A.L., Litasov, K.D., Shatsky, V.S.The role of eclogites in the redistribution of water in the subcontinental mantle of the Siberian craton: results of determination of the water content in minerals from the Udachnaya pipe eclogites.Russian Geology and Geophysics, Vol. 59, 7, pp. 763-779.Russia, Siberiadeposit - Udachnaya

Abstract: A comprehensive study of 26 mafic mantle xenoliths from the Udachnaya kimberlite pipe was carried out. The contents of major and trace elements, equilibrium temperature parameters, and water content in the rock-forming minerals were determined. The temperatures of formation of the studied rocks are estimated at 800-1300 °C. According to IR spectroscopy data, the water content in clinopyroxenes from the studied eclogites varies from values below the detection limit to 99 ppm. The IR spectra of garnets lack bands of water. The water content in clinopyroxene and orthopyroxene from garnet websterite is 72 and 8 ppm, respectively. The water content in the average rock, calculated from the ratio of the rock-forming minerals, varies from a few to 55 ppm. No relationship among the water content, equilibrium temperatures, and rock composition is established. The low water contents in the eclogites are close to the earlier determined water contents in peridotites from the same pipe and are, most likely, due to the re-equilibration of the eclogites with the rocks of the peridotitic lithospheric mantle. The dehydration of the protolith during its subduction and the partial melting of eclogites before their removal by kimberlitic magma to the surface might be an additional cause of the low water contents in the mantle eclogite xenoliths.
DS201811-2622
2018
Ragozin, A.L.Zedgenizov, D.A., Ragozin, A.L., Shatsky, V.S., Griffin, W.L.Diamond formation during metasomatism of mantle eclogite by chloride-carbonate melt.Contributions to Mineralogy and Petrology, Vol. 173, 16p. Doi.org/10.1007/s00410-018-1513-yRussiadeposit - Udachnaya

Abstract: A xenolith of bimineralic eclogite from the Udachnaya kimberlite pipe provides a snapshot of interaction between mantle rocks and diamond-forming fluids/melts. The major-element composition of the eclogite is similar to that of N-MORB and/or oceanic gabbros, but its trace-element pattern shows the effects of mantle metasomatism, which resulted in diamond formation. The diamonds are clustered in alteration veins that crosscut primary garnet and clinopyroxene. The diamonds contain microinclusions of a fluid/melt dominated by carbonate and KCl. Compared to the worldwide dataset, the microinclusions in these diamonds fall in middle of the range between saline fluids and low-Mg carbonatitic melts. The fluid/melt acted as a metasomatic agent that percolated through ancient eclogitic rocks stored in the mantle. This interaction is consistent with calculated partition coefficients between the rock-forming minerals and diamond-forming fluid/melt, which are similar to experimentally-determined values. Some differences between the calculated and experimental values may be due to the low contents of water and silicates in the chloride-carbonate melt observed in this study, and in particular its high contents of K and LILE. The lack of nitrogen aggregation in the diamonds implies that the diamond-forming metasomatism took place shortly before the eruption of the kimberlite, and that the microinclusions thus represent saline carbonate-rich fluids circulating in the basement of lithospheric mantle (150-170 km depth).
DS201908-1814
2019
Ragozin, A.L.Shatsky, V.S., Wang, Q., Skuszovatov, S.Y., Ragozin, A.L.The crust mantle evolution of the Anabar tectonic province in the Siberian craton: coupled or decoupled?Precambrian Research, Vol. 332, 105388 15p. Russia, Siberiadeposit - Udachnaya, Zarnitsa, Komsomolskaya

Abstract: To clarify the tectonic-thermal evolution of the Anabar tectonic province in the central Siberian Craton, we performed an isotope-geochemical study of 20 xenoliths from the Udachnaya, Zarnitsa, and Komsomolskaya kimberlite pipes to represent different crustal levels. Most mafic granulites have Proterozoic Nd model ages and geochemical characteristics close to those of intraplate basalts, whereas some mafic and intermediate granulites with Archean model ages exhibit geochemical features of supra-subduction ophiolitic basalts. Analysis of U-Pb ages and hafnium isotopic composition of zircon indicates that the main tectonic-thermal events modified the crust at 2.7 and 1.9-1.8?Ga, which is consistent with ages of mantle depletion events from previous studies. All zircons have Archean Hf model ages (3.2?Ga). Overall, thermal events with ages of 2.9-2.8, 2.7, 2.4, 1.97 and 1.8?Ga have remarkable influence on the studied zircons. Tectono-thermal events at 2.4 1.97, 1.9 and 1.8?Ga with no addition of juvenile material are recorded by zircons from xenoliths of mafic and intermediate granulites and metadiorites. A compilation of isotope-geochemical data demonstrates that instead of age-stratified, the crust of the Anabar tectonic province consists of variably reworked Paleoarchean rocks and juvenile Proterozoic rocks at all crustal levels. Hence the crust and mantle of the Siberian Craton has been coupled since the Paleoarchean.
DS201910-2312
2019
Ragozin, A.L.Zedgenizov, D.A., Ragozin, A.L., Kagi, H., Yurimoto, H., Shatsky, V. S.SiO2 inclusions in sublithospheric diamonds.Geochemistry International, Vol. 57, 9, pp. 964-972.Mantlediamond inclusions

Abstract: The paper describes mineralogical characteristics of SiO2 inclusions in sublithospheric diamonds, which typically have complicated growth histories showing alternating episodes of growth, dissolution, and postgrowth deformation and crushing processes. Nitrogen contents in all of the crystals do not exceed 71 ppm, and nitrogen is detected exclusively as B-defects. The carbon isotope composition of the diamonds varies from ?13? = -26.5 to -6.7‰. The SiO2 inclusions occur in association with omphacitic clinopyroxenes, majoritic garnets, CaSiO3, jeffbenite, and ferropericlase. All SiO2 inclusions are coesite, which is often associated with micro-blocks of kyanite in the same inclusions. It was suggested that these phases have been produced by the retrograde dissolution of primary Al-stishovite, which is also evidenced by the significant internal stresses in the inclusions and by deformations around them. The oxygen isotope composition of SiO2 inclusions in sublithospheric diamonds (?18O up to 12.9‰) indicates a crustal origin of the protoliths. The negative correlation between the ?18O of the SiO2 inclusions and the ?13C of their host diamonds reflects interaction processes between slab-derived melts and reduced mantle rocks at depths greater than 270 km.
DS202005-0760
2020
Ragozin, A.L.Shatsky, V.S., Ragozin, A.L., Logvinova, A.M., Wirth, R.Diamond-rich placer deposits from iron-saturated mantle beneath the northeastern margin of the Siberian craton.Lithos, Vol. 364-365, 12p. PdfRussiadeposit - Olenek

Abstract: We demonstrate for the first time the presence of iron carbides in placer diamonds from the northeastern region of the Siberian craton. It was found that the inclusions are polycrystalline aggregates, and iron carbides filling the fissures in the diamonds, thus providing clear evidence that the iron melts were captured first. Iron carbides were identified in diamonds containing mineral inclusions of eclogitic (Kfs, sulfide) and peridotitc (olivine) paragenesis. Iron carbides with minor amounts of admixed nickel were detected in a diamond sample containing an olivine inclusion (0.3 wt% Ni), indicating that the iron melt was not in equilibrium with the mantle peridotite.The low nickel contents of the iron carbides provide the best evidence that the subducted crust is a likely source of the iron melt. Diamonds containing carbide inclusions are characterised by a relatively low nitrogen aggregation state (5-35%), which is not consistent with the high temperature of the transition zone. Therefore, we have reason to assume that the studied diamonds are from the lower regions of the lithosphere. Considering all factors, the model for the interaction of the ascending asthenospheric mantle with the subducting slab seems to be more realistic.
DS202010-1876
2020
Ragozin, A.L.Shatsky, V.S., Ragozin, A.L., Kozmenko, O.A., Denisenko, A.A.Geochemical evidence for participation of the subducted crust in the process of transformation of the subcontinental mantle in the Yakutian diamondiferous province.Doklady Earth Sciences, Vol. 493, 1, pp. 513-516. pdfRussia, Yakutiasubduction

Abstract: The data available indicate the complex evolution of deformed peridotites of mantle xenoliths, the P-T parameters of which indicate that they are fragments of the metasomatized lower part of the cratonic lithosphere. The zoning established in garnets from xenoliths in kimberlite pipes is interpreted as a result of metasomatism that occurred shortly before xenoliths reached the surface. Metasomatic alterations in xenoliths of deformed harzburgites were manifested not only in the development of zoning of minerals. The study results show that there is a discrepancy between the data calculated based on the contents of incompatible elements in minerals of xenoliths and those obtained due to direct measurements of the bulk composition of xenoliths. To determine the balance of incompatible elements, we have carried out experiments on leaching xenoliths of deformed lherzolites from the Udachnaya kimberlite pipe. It was established that a significant part of LREEs in the studied xenoliths occurs in the intergranular space. The distribution pattern of incompatible elements and, in particular, the presence of a positive Eu anomaly indicate that the appearance of the intergranular component is not associated with contamination of xenoliths by the kimberlite melt. Quite a few xenoliths demonstrate a positive Eu anomaly, which indicates the influence of the subducted crustal component at one of the modification stages of xenoliths.
DS202011-2070
2020
Ragozin, A.L.Zemnukhov, A.L., Reutsky, V.N., Zedgenizov, D.A., Ragozin, A.L., Zhelonkin, R.Y., Kalinina, V.V.Subduction related population of diamonds in Yakutian placers, northeastern Siberian platform.Contributions to Mineralogy and Petrology, Vol. 175, 98 10.1007/s00410-020-01741-w 11p. PdfRussia, Yakutiadiamond crystallography

Abstract: The 35 paired diamond intergrowths of rounded colorless transparent and gray opaque crystals from the placers of northeastern Siberian Platform were investigated. Mineral inclusions (KFsp, Coe, E-Grt, Po) detected in studied samples belong to eclogitic paragenesis. The majority of studied samples have uniform ranges of nitrogen content (1126-1982 at. ppm) and carbon isotope composition (??16.8 to ??23.2 ‰). These characteristics pointing towards subducted material are possible sources for their genesis. Two samples consist of a gray opaque crystal with the subduction-related characteristics (?13C ca. ??21‰ and N ca. 1300 at. ppm) and a transparent crystal with low nitrogen content (412 and 29 at. ppm) and a heavy carbon isotopic composition (?13C ??4.2 and ??4.6‰) common for primary mantle range. The higher degree of nitrogen aggregation in the crystals with mantle-like characteristics testifies their longer storage in the mantle conditions. These samples reflect multistage diamond growth history and directly indicate the mixing of mantle and subduction carbon sources at the basement of subcontinental lithospheric mantle of northeastern Siberian Platform.
DS202102-0224
2020
Ragozin, A.L.Skuzovatov, S.Yu., Shatsky, V.S., Ragozin, A.L., Wang, K-L.Ubiquitous post-peak zircon in an eclogite from the Kumdy-Kol, Kokchetav UHP-HP massif ( Kazakhstan): significance of exhumation-related zircon growth and modification in continental-subduction settings.Island Arc, doi:10.1111/ iar.12385 29p. PdfRussia, Kazakhstandeposit - Kumby-Kol

Abstract: U-Pb geochronological, trace?element and Lu-Hf isotopic studies have been made on zircons from ultrahigh?pressure (UHP) mafic eclogite from the Kumdy?Kol area, one of the diamond?facies domains of the Kokchetav Massif (northern Kazakhstan). The peak eclogitic assemblage equilibrated at >?900?°C, whereas the bulk sample composition displays light rare?earth element (LREE) and Th depletion evident of partial melting. Zircons from the eclogite are represented by exclusively newly formed metamorphic grains and have U-Pb age spread over 533-459?Ma, thus ranging from the time of peak subduction burial to that of the late post?orogenic collapse. The major zircon group with concordant age estimates have a concordia age of 508.1?±4.4?Ma, which corresponds to exhumation of the eclogite?bearing UHP crustal slice to granulite? or amphibolite?facies depths. This may indicate potentially incoherent exhumation of different crustal blocks within a single Kumdy?Kol UHP domain. Model Hf isotopic characteristics of zircons (?Hf(t) +1.5 to +7.8, Neoproterozoic model Hf ages of 1.02-0.79?Ga) closely resemble the whole?rock values of the Kumdy?Kol eclogites and likely reflect in situ derivation of HFSE source for newly formed grains. The ages coupled with geochemical systematics of zircons confirm that predominantly late zircon growth occurred in Th-LREE?depleted eclogitic assemblage, that experienced incipient melting and monazite dissolution in melt at granulite?facies depths, followed by amphibolite?facies rehydration during late?stage exhumation?related retrogression.
DS202107-1127
2021
Ragozin, A.L.Shatsky, V.S., Ragozin, A.L., Skuzovatov, S. Yu., Kozmenko, O.A., Yagoutz, E.Isotope-geochemical evidence of the nature of protoliths of diamondiferous rocks of the Kokchetav subduction-collision zone ( northern Kazakhstan).Russian Geology and Geophysics, Vol. 62, pp. 547-556, pdfRussia, Kazakhstandeposit - Kokchetav

Abstract: The isotope-geochemical features of diamondiferous metamorphic rocks of the Kokchetav subduction–collision zone (KSCZ) show that both the basement rocks and the sediments of the Kokchetav massif were their protoliths. A whole-rock Sm–Nd isochron from the diamondiferous calc-silicate, garnet–pyroxene rocks and migmatized granite-gneisses of the western block of the KSCZ yielded an age of 1116 ± 14 Ma, while an age of 1.2–1.1 Ga was obtained by U–Pb dating of zircons from the granite-gneiss basement of the Kokchetav microcontinent. Based on these data, we assume that the protoliths of the calc-silicate, garnet–pyroxene rocks and the granite-gneisses of the KSCZ were the basement rocks sharing an initially single Nd source, which was not influenced by high- to ultrahigh-pressure metamorphism (~530 Ma). Therefore, their geochemical features are probably not directly related to ultrahigh-pressure metamorphism. The corresponding rock associations lack isotope-geochemical evidence of partial melting that would occur during ultrahigh-pressure metamorphism, which suggesting that they were metamorphosed under granulite-facies conditions. At the same time, the high-alumina diamondiferous rocks of the Barchi area (garnet–kyanite–mica schists and granofelses), which were depleted to different degrees in light rare-earth elements (REE) and K, have yielded a Sm–Nd whole-rock isochron age of 507 ± 10 Ma indicating partial melting of these rocks during their exhumation stage. The close ?Nd (1100) values of the basement rocks and garnet–kyanite–mica schist with geochemical characteristics arguing against its depletion during high-pressure metamorphism indicate that the basement rocks were a crustal source for high-alumina sediments.
DS202202-0215
2021
Ragozin, A.L.Shatsky, V.S., Ragozin, A.L., Sitnikova, E.S.The nature of heterogeneity of high-chromium garnets in xenolite of deformed lherzolite from Udachnaya kimberlite pipe ( Yakutia).Doklady Earth Sciences, Vol. 501, pp. 1029-1037.Russia, Yakutiadeposit - Udachnaya

Abstract: Significant variations in the composition of garnets, both within individual grains and in the rock, are found in the xenolith of deformed garnet lherzolite from the Udachnaya kimberlite pipe. The central parts of the grains, corresponding in composition to the garnets of the lherzolite paragenesis, demonstrate a sinusoidal distribution of rare earth elements (REEs). At the same time, the edge portions have a distribution characteristic of garnet mega-crystals from kimberlites. Despite being depleted in Y and HREE, the cores are enriched in light rare earth elements, Nb, Ta, Th, and U relative to garnet from primitive garnet peridotite. In terms of the REE distribution, the model melts, which are in equilibrium with the edge parts of garnet, are close to kimberlite but are significantly enriched in comparison with kimberlite in Nb, Ta, and Hf and depleted in Sr. Melts in equilibrium with the central parts of garnet are characterized by a steeper negative slope in the region of heavy and medium REEs and approach kimberlite in the region of light REEs. Based on the data obtained, several stages in the evolution of deformed garnet lherzolite are distinguished. The first stage involves the interaction of depleted peridotite with a melt similar in composition to carbonatite melts. This stage is associated with the formation of garnet with a sinusoidal REE distribution. At the next stage, which was preceded by the dissolution of garnet grains, garnet rims with increased Ti, Zr, and Y contents were formed and clinopyroxene appeared. At the final stage, garnet melted, caused by the inflow of a water-carbon dioxide fluid with a high potassium content, leading to polymineral inclusions and kelyphite rims.
DS202205-0713
2022
Ragozin, A.L.Rakhmanova, M.I., Komarovskikh, A.Y., Ragozin, A.L., Yuryeva, O.P., Nadolinny, V.A.Sprectroscopic features of electron-irradiated diamond crystals from the Mir kimberlite pipe, Yakutia.Diamond and Related Materials, Vol. 126, 109057Russiadeposit - Mir

Abstract: The behavior of characteristic centers in diamond crystals from the Mir pipe (Yakutia) was investigated upon electron irradiation. A series of diamond crystals of different types was chosen for experiments based on the nitrogen content and aggregation parameters. In electron-irradiated diamonds of the IaAB type, a new characteristic photoluminescence system was found with a zero-phonon line (ZPL) at 615 nm together with phonon replicas of 41 and 90 meV. The phonons' energies pointed to multiphonon interactions with a quasilocal vibration of a vacancy. According to our data, the nitrogen-related defect responsible for this phenomenon contains a vacancy and may be accompanied by some other impurity. Conversely, in an almost nitrogen-free crystal, a specific system with the ZPL at 558 nm was noted. The center in question is known to be vacancy-related and was formed in type IIa crystals from the Mir pipe not only by electron irradiation but also by high-pressure high-temperature annealing when vacancies were released as a result of motion or annihilation of dislocations. Regardless of the nitrogen impurity, specific systems with the ZPL at 454, 491, and 492 nm were registered in the irradiated diamond crystals from the Mir pipe. To examine the generated defects, the irradiated diamond crystals were subjected to low-temperature annealing at ?600 °C. Although the 454 and 491 nm systems persisted, the annealing of the 492 nm system along with well-known 523.6, 489.0, and 503.4 nm (3H) centers indicated the interstitial-vacancy nature of the defect.
DS202205-0718
2022
Ragozin, A.L.Skuzovatov, S.Y., Shatsky, V.S., Wang, Q., Ragozin, A.L.,Kostrovitsky, S.T.Multiple tectonomagmatic reactivation of the unexposed basement in the northern Siberian craton: from Paleoproterozoic orogeny to Phanerozoic kimberlite magmatism.International Geology Review, Vol. 64, 8, pp. 1119-1138.Russia, Siberiakimberlite magmatism

Abstract: Zircon xenocrysts from two diamond-barren kimberlite pipes (Leningrad and Ruslovaya) in the West Ukukit kimberlite field opened a ‘window’ to the buried crustal basement in the northern Siberian craton. Zircon U-Pb ages reveal a close affinity of the basement of the Khapchan belt to the Archaean Anabar province and a significant tectonomagmatic reworking in the Paleoproterozoic (~2.1-1.8 Ga) due to collision between the Anabar province and the Olenek province. The West Ukukit kimberlite field experienced multiple tectonomagmatic reactivation from ~670 to 144 Ma, which can be attributed to interaction of the deep crust with mantle-derived melts. Hf isotope composition of zircon xenocrysts reveals significant addition of juvenile material into the crust during the Paleoproterozoic orogeny in diamond-barren kimberlite fields, which is different from the reworking crust in the southern Yakutia diamondiferous kimberlite fields. Eruption of the Leningrad and Ruslovaya pipes were constrained as the Late Jurassic, much later than the well-known Late Silurian-Earth Devonian kimberlites in the West Ukukit kimberlite field. A NE-trending, >2000 km long kimberlite corridor is proposed to account for a prolonged lithospheric channel for episodic eruption of kimberlites in the Siberian craton. The diamond storage in the lithosphere beneath the West Ukukit kimberlite field may have been largely reduced by the Paleoproterozoic orogeny and Phanerozoic reworking.
DS201112-0012
2010
Rahal Lenharo, S.L.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
DS201012-0418
2010
Raharimahefa, T.Kusky, T.M., Toraman, E., Raharimahefa, T., Rasoazanamparany, C.Active tectonics of the Alatra Ankay graben system, Madagascar: possible extension of Somalian African diffusive plate boundary?Gondwana Research, Vol. 18, 2-3, pp. 274-294.Africa, MadagascarTectonics
DS1998-1202
1998
Rahe, B.Rahe, B., Ferrill, D.A., Morris, A.P.Physical analog modeling of pull apart basin evolutionTectonophysics, Vol. 285, No. 1-2, Feb. 15, pp. 21-86GlobalBasin, Tectonics, structure, model
DS200912-0608
2008
Rahfeldt, T.Rahfeldt, T., Foley, S.F., Jacob, D.E., Carlson, R.W., Lowry, D.Contrasting types of metasomatism in dunite, wherlite and websterite xenoliths from Kimberley, South Africa.Geochimica et Cosmochimica Acta, Vol. 72, 5722-36.Africa, South AfricaDeposit - Kimberley
DS201412-0869
2014
Rahgoshay, M.Soltanmohammadi, A., Rahgoshay, M., Ceuleneer, G.Clinopyroxene composition of mafic-ultramafic xenoliths in alkaline rocks, northwestern Iran: an example of cognate type xenoliths in lamprophyres.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, IranXenoliths
DS202111-1773
2021
Rahimzadeh, B.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.
DS2002-1299
2002
Rahl, J.M.Rahl, J.M.,McGrew, A.J., Foland, K.A.Transition from contraction to extension in the northeastern Basin and Range: new evidence from...Journal of Geology, Vol.110,1,pp. 179-94.NevadaTectonics, Copper Mountains area
DS2000-0791
2000
Rahmanov, K.Rahmanov, K.Potassic alkaline basaltoids of the Middle Tien Shan. ( Chatkal and KouramaIgc 30th. Brasil, Aug. abstract only 1p.ChinaShoshonite
DS202007-1176
2019
RaiSaha, G., Rai, S,S., ShalivahanOccurrence of diamond in peninsular India and its relationship with deep Earth seismic properties.Journal of Earth System Science, Vol. 128, 43, 8p. PdfIndiageophysics, seismics

Abstract: An improved shear wave velocity (Vs) structure of the lithosphere of peninsular India using the surface wave tomography from the ambient noise and earthquake waveforms suggests its bipolar character. While most of the geological domains of India are characterised by a uniform lithospheric mantle of Vs?4.5 km/s, the three cratonic regions, eastern Dharwar, Bastar and Singhbhum, hosting most of the diamondiferous kimberlite fields, show significantly high Vs of 4.7 km/s and above in their lower lithosphere beyond ?90 km depth. The higher velocity could best be explained by the presence of diamond and/or eclogite along with peridotite in mantle. This unique relationship suggests the regional seismic image of lithosphere as a guide for exploration of diamonds.
DS200912-0609
2009
Rai, A.Rai, A., Gaur, V.K., Rai, S.S., Preistley, K.Seismic signatures of the Pan-African orogeny: implications for southern Indian high grade terranes.Geophysical Journal International, Vol. 176, 2, pp. 518-528.IndiaUHP
DS201905-1070
2019
Rai, A.K.Rai, A.K., Srivastava, R.K., Samal, A.K., Sesha Sai, V.V.Geochemistry, petrogenesis, and geodynamic implications of NE-SW to ENE - WSW trending Paleoproterozoic mafic dyke swarms from southern region of the western Dharwar Craton.Geological Journal, Doi: 10.1002/gj.3493Indiageodynamics

Abstract: A number of NE-SW to ENE-WSW trending Palaeoproterozoic mafic dykes, intruded within the Archean basement rocks and more conspicuous in the southern parts of the western Dharwar Craton (WDC), was studied for their whole?rock geochemistry to understand their petrogenetic and geodynamic aspects. Observed mineralogical and textural characteristics classify them either as meta?dolerites or dolerites/olivine?dolerites. They show basaltic to basaltic-andesitic compositions and bear sub?alkaline tholeiitic nature. Three geochemically distinct groups of mafic dykes have been identified. Group 1 samples show flat REE patterns (LaN/LuN = ~1), whereas the other two groups have LaN/LuN = ~2-3 (Group 2; enriched LREE and flat HREE patterns) and LaN/LuN = ~4 (Group 3; inclined REE patterns). Chemistry is not straightforward to support any significant role of crustal contamination and probably reflect their source characteristics. However, their derivation from melts originated from a previously modified metasomatized lithospheric mantle due to some ancient subduction event cannot be ignored. Most likely different mantle melts were responsible for derivation of these distinct sets of mafic dykes. The Group 2 dykes are derived from a melt generated within spinel stability field by ~10% batch melting of a lithospheric mantle source, whereas the Group 3 dykes have their derivation from a melt originated within the spinel-garnet transition zone and were fed from slightly higher (~12-15%) batch melting of a similar source. The Group 1 samples were also crystallized from a melt generated at the transition zone of spinel-garnet stability field by higher degrees (~20%) of melting of a primitive mantle source. Geochemistry of the studied samples is typical of Palaeoproterozoic mafic dykes emplaced within the intracratonic setting, reported elsewhere globally as well as neighbouring cratons. Geochemistry of the studied mafic dyke samples is also compared with the mafic dykes of the eastern Dharwar Craton (EDC). Except the Group 3 samples, which have good correlation with the 1.88-1.89 Ga Hampi swarm, no other group shows similarity with the EDC mafic dykes. There is an ample possibility to have some different mafic magmatic events in the WDC, which could be different from the EDC. However, it can only be confirmed after precise age determinations.
DS201412-0719
2013
Rai, S.BorahRai, S.Borah, Kajaljyoti, Das, Gupta, R., Srivastava, S., Shalivahan, P., Sivaram, K., Kumar, K., Meena, S.The South India Precambrian crust and shallow lithospheric mantle: initial results from the India Deep Imaging Experiment ( INDEX).Journal of Earth System Science, Vol. 122, 6, pp. 1435-1453.IndiaDrilling
DS201801-0041
2017
Rai, S.D.Nanda. L.K., Verma, M.B., Purohit, R.K., Khandelwal, M.K., Rai, S.D., Mundra, K.L.LREE and Nb multi metal potentiality of the Amba Dongar carbonatite complex, Chhota Udepur district, Gujarat.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 43-44.Indiadeposit - Amba Dongar

Abstract: Rare earth elements (REE) are used in science innovations, due to their unique magnetic, fluorescent and chemical properties. REE are key components in rnany technological devices, like hybrid rechargeable batteries, catalysts, glass polishing, magnets, lasers, TV colour components, superconductors, ceramics etc. They are in great demand for hybrid cars, CD, cameras and high end defence systems. Similarly, niobium (Nb) finds its usage in diverse high tech applications including atomic energy. With increasing technological applications of REE and Nb, their global demand has enhanced over the years. To keep pace with the current demand, many carbonatite complexes in India including the Amba Dongar were revisited to assess their REE and Nb content. Amba Dongar is a classic carbonatite-alkalic rock complex of the Deccan basalt plateau and is emplaced in close proximity to Narmada rift zone. The main rock types of carbonatite affinity include sovite (calcium carbonatite), ankerite (Fe-Mg•Mn carbonatite), siderite (Fe carbonatite), carbonatite breccia (mixed rock. fragments with carbonate cement) etc. Sovite forms a large ring-dyke (nearly 1.5 km dia.) surrounding an incomplete ring of carbonatite breccia. Plugs of ankeritic carbonatite intrude the sovite. To assess rare metal and REE potential of the carbonatite complex geological and radiometric surveys followed by core drilling were carried out in western part of the complex. Rocks of carbonatite affinity have been intercepted in all the boreholes upto a maximum drilled depth of 150 m. It is for the first time that presence of carbonatite and carbonatite breccia has been reported below central basalt in the Amba Dongar complex. Continuity of carbonatites beyond the drilled depth is inferred. Petromineralogical and X-Ray Diffraction studies indicated presence of REE minerals such as monazite, thorite, cerite, synchisite and bastnasite. Besides, rare earth fluorocarbonates, parisite, florencite, barite, strontianite and columbite have also been reported by earlier investigators. Fairly good amount of pyrochlore (Nb mineral) is also present in all the variants of carbonatite. Detailed chemical analysis core at 1 m interval and of composite samples from every borehole was carried out. The results indicate homogeneity of mineralisation in the entire column upto an explored vertical depth of 120 m. Except a few lean zones, the entire column hosts REE mineralisation of the order of >1% ?REE. Some zones have indicated REE mineralisation of the order of >4 % also. Major element analysis of a composite sample representing a small block (400 m x 100 m x 113 m) indicates 14.69% SiO2, 10.57% Fe2O3, 7 21% MgO, 32.23% CaO, 2.77%, Al2O3, 1.48% P2O5, 2.13% MnO, 0.84% FeO, 0.37% TiO2, 0.95% Na2O, 1.35% K2O, and 23.50% LOI. 1.16% LREE (including 161 ppm HREE), 215 ppm Y, 650 ppm Nb, 310 ppm Th and 467 ppm V appear to be of economic significance. Additionally, presence of high content of Ba (2.65%), Sr (0.50%), Pb (530 ppm), F (1.95%) and Zn (1248 ppm) is also important. Taking into consideration these results, resource estimation of a small block of 400 m x 100 m (0.04 sq. km) with an average depth of 113 m was carried out Inferred REE resources ~140000 tonnes contained in 12.00 million tonne ore have been estimated with an average grade of 1.16% REE. Additionally, this block contains 9,600 tonnes Nb2O5 at an average grade of 0 08 % Nb2O5. These values indicate high potential of Amba Dongar carbonatite complex.
DS2000-0388
2000
Rai, S.K.Hari, K.R., Kumar, M.S., Santosh, M., Rai, S.K.Melt inclusions in olivine and pyroxene phenocrysts from lamprophyres of Chhaktalao area.Journal of Asian Earth Science, Vol. 18, No.2, Apr. pp. 155-61.India, Madhya PradeshLamprophyres
DS1985-0553
1985
Rai, S.S.Rai, S.S.Crone pulse electromagnetic response of a conductive thinhorizontalsheet; theory and field applicationGeophysics, Vol. 50, No. 8, pp. 1350-1354India, Andhra PradeshWajakarur, Geophysics
DS1986-0660
1986
Rai, S.S.Rai, S.S., Bhattacharya, B.B.Quantitative interpretation of pulse electromagnetic measurements over a weathered kimberlite diatremeGeophysical Prospecting, Vol. 34, pp. 220-231IndiaGeophysics
DS1989-1442
1989
Rai, S.S.Sringesh, D., Rai, S.S., Ramesh, D.S., Gaur, V.K., Rao, C.V.R.Evidence for thick continental roots beneath South Indian shieldGeophysical Research Letters, Vol. 16, No. 9, September pp. 1055-1058IndiaMantle
DS2003-0522
2003
Rai, S.S.Gupta, S., Rai, S.S., Prakasam, K.S., Srinagesh, D., Basal, B.K., Chadha, R.K.The nature of the crust in southern India: implications for Precambrian crustal evolutionGeophysical Research Letters, Vol. 30, 8, 10.1029/2002GLO16770IndiaTectonics
DS2003-0523
2003
Rai, S.S.Gupta, S., Rai, S.S., Prakasam, K.S., Sringesh, D., Chadha, R.K., Priestly, K.First evidence for anomalous thick crust beneath mid Archean western Dharwar cratonCurrent Science, Vol. 84, 9, pp. 1219-26.IndiaCraton
DS2003-1100
2003
Rai, S.S.Prakasam, K.S., Rai, S.S.Crustal thickening and composition in eastern Dharwar CratonMemoirs Geological Society of India, Vol. 53, pp. 115-128. Ingenta 1035483299IndiaBlank
DS200412-0750
2003
Rai, S.S.Gupta, S., Rai, S.S., Prakasam, K.S., Srinagesh, D., Basal, B.K., Chadha, R.K., Priestly, K., Gaur, V.K.The nature of the crust in southern India: implications for Precambrian crustal evolution.Geophysical Research Letters, Vol. 30, 8, 10.1029/2002 GLO16770IndiaTectonics
DS200412-0751
2003
Rai, S.S.Gupta, S., Rai, S.S., Prakasam, K.S., Sringesh, D., Chadha, R.K., Priestly, K., Gaur, V.K.First evidence for anomalous thick crust beneath mid Archean western Dharwar craton.Current Science, Vol. 84, 9, pp. 1219-26.IndiaCraton
DS200412-1576
2003
Rai, S.S.Prakasam, K.S., Rai, S.S.Crustal thickening and composition in eastern Dharwar Craton.Memoirs Geological Society of India, Vol. 53, pp. 115-128. Ingenta 1035483299IndiaGeochemistry
DS200812-0573
2008
Rai, S.S.Kiselev, S., Vinnik, L., Oreshin, S., Gupta, S., Rai, S.S., Singh, A., Kumar, Mohan.Lithosphere of the Dharwar craton by joint inversion of P and S receiver functions.Geophysical Journal International, In press ( available)IndiaGeophysics - seismics
DS200912-0292
2009
Rai, S.S.Heintz, M., Kumar, V.P., Gaur, V.K., Priestly, K., Rai, S.S., Prakasam, K.S.Anisotropy of the Indian continental lithospheric mantle.Geophysical Journal International, Vol. 179, 3, pp. 1341-1360.IndiaGeodynamics
DS200912-0609
2009
Rai, S.S.Rai, A., Gaur, V.K., Rai, S.S., Preistley, K.Seismic signatures of the Pan-African orogeny: implications for southern Indian high grade terranes.Geophysical Journal International, Vol. 176, 2, pp. 518-528.IndiaUHP
DS201112-0762
2011
Rai, S.S.Oreshin, S.I., Vinnik, L.P., Kiselev, S.G., Rai, S.S., Prakasam, K.S., Treussov, A.V.Deep seismic structure of the Indian shield, western Himalaya, Ladakh, and Tibet.Earth and Planetary Science Letters, Vol. 307, 3-4, pp. 415-429.IndiaSubduction
DS201312-0571
2012
Rai, S.S.Mandal, N., Charavarty, K.H., Borah, K., Rai, S.S.Is a cation ordering transition of the Mg-Fe olivine phase in the mantle responsible for the shallow mantle seismic discontinuity beneath the Indian craton?Journal of Geophysical Research, 9225IndiaHales discontinuity
DS201510-1764
2015
Rai, S.S.Das, R., Saikia, U., Rai, S.S.The deep geology of South India inferred from Moho depth and Vp/Vs ratio.Geophysical Journal International, Vol. 203, pp. 910-926.IndiaGeophysics - seismics

Abstract: We present a comprehensive study of thickness and composition of the crust; and the nature of crust-mantle boundary beneath Southern India using P-wave receiver function from 119 seismic stations. Data from distributed network of seismograph location encompass geological domains like mid to late Archean Dharwar craton, Archean and Proterozoic metamorphic terrains, Proterozoic basin, rifted margins and escarpments, and Deccan volcanics. Except for the mid to lower crust exhumed Archean terrains (of West Dharwar and Southern Granulite) all other geological domains have crustal thickness in the range 33-40 km. In the western Dharwar, crustal thickness increases from ?40 km in the north to over 50 km in the south. The Archean domain of granulite terrain is thicker (40-45 km) and more mafic compared to its counterpart in south deformed at 550 Ma. Most of the crustal blocks have low to moderate Vp/Vs (1.72-1.76) representing a felsic to intermediate composition. Exception to the above include Archean granulite terrain with high Vp/Vs (1.76–1.81) suggestive of more mafic crust beneath them. When accounted for the paleo burial depth of 15-25 km, the study suggests a possible Himalaya-Tibet like scenario beneath the mid-late Archean in southwestern Dharwar and north granulite terrain whose deeper crust has progressively densified. This led to a gradational crust-mantle transition that is otherwise sharp elsewhere. The study suggests a more homogenized and felsic nature of the Precambrian crust beneath the terrains formed after 2.6 Ga, possibly due to delamination of the mafic lower crust. Our study does not suggest any distinction between late Archean and Proterozoic crust. The Deccan volcanism at 65 Ma does not appear to have altered the crustal character beneath it and is similar to the adjoining late Archean east Dharwar craton. The western Ghat escarpment and the coastal plain formed due to separation of India from Madagascar are underlain by mafic lower crust.
DS201904-0776
2019
Rai, S.S.Saikia, U., Jumar, V.P., Rai, S.S.Complex upper mantle deformation beneath the Dharwar craton inferred from high density splitting measurements: distinct lateral variation from west to east.Tectonophysics, Vol. 755, pp. 10-20.Indiageophysics - seismics

Abstract: Upper mantle anisotropy investigated using 172 core-refracted (SKS, SKKS) seismic phases along a ~660?km long profile at 10 to 20?km intervals from the west to the east coast of South India reveals significant lateral variations in its magnitude and direction. This profile, with 38 broadband seismic stations, covers mid-Archean Western Dharwar craton (WDC), late-Archean Eastern Dharwar Craton (EDC), Proterozoic Cuddapah Basin (CB) and the passive continental margins along the west and east coast. The observed fast polarization directions (FPDs) show lateral variability: NW50o to NW5o beneath the WDC, NW40o to NE30o beneath the EDC and N5o to N85o beneath the CB and further east. The delay time varies between 0.4 and 2.0?s with an average of 1?s. However, we are unable to fit a two layers anisotropy model for the region due to sparse azimuth coverage. Beneath the WDC, the direction of the fast axis follows trends of shear zones and faults, suggesting “frozen-in” anisotropy in the lithosphere, possibly established during the lithospheric evolution in mid-late Archean. In the EDC, the fast axis does not only follow the plate motion direction but it deviates, manifesting late Archean to Proterozoic deformation may still be present as fossil mantle anisotropy. The splitting trend beneath the CB and Eastern Ghat (EG) follows the strike of the rift along with plate motion direction, indicating anisotropy is influenced by the combination of “frozen” anisotropy due to continental rifting along the eastern margin of Indian plate and active asthenospheric flow.
DS201112-0440
2011
Rai, V.Hofmann, M., Linnemann, U., Rai, V., Becker, S., Gartner, A., Sagawe, A.The India and South Chin a cratons at the margin of Rodinia - synchronous Neoproterozoic magmatism revealed by LA-ICP-MS zircon analyses.Lithos, In press available 65p.India, ChinaMagmatism
DS201312-0736
2013
Rai, V.K.Ray, J.S., Pnde, K., Bhutani, R., Shukla, A.D., Rai, V.K., Kumar, A., Awasthi, N., Smitha, R.S., Panda, D.K.Age and geochemistry of the Newania dolomite carbonatites, India: implications for the source of primary carbonatite magma.Contributions to Mineralogy and Petrology, Vol. 166, 6, pp. 1613-1632.IndiaCarbonatite
DS2001-0958
2001
Raiche, A.Raiche, A.Choosing an AEM system to look for kimberlites - a modelling studyExploration Geophysics, (ASEG Bulletin.), Vol. 32, No. 1, March pp. 1-8.GlobalGeophysics - TEM, AEM, HEM., Methodology - techniques
DS200512-0485
2005
Raimbourg, H.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
DS200712-0865
2006
Raimbourg, H.Raimbourg, H., Jolivet, L., Leroy, Y.Consequences of progressive eclogization on crustal exhumation, a mechanical study.Geophysical Journal International, Vol. 168, 1, pp. 379-401.TechnologyEclogite
DS200812-0931
2008
Raimbourg, H.Raimbourg, H., Kimura, G.Non-lithostatic pressure in subduction zones.Earth and Planetary Science Letters, Vol. 274, pp. 414-422.MantleSubduction
DS201312-0012
2013
Raimondo, T.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
DS201412-0720
2013
Raimondo, T.Raimondo, T., Hand, M., Collins, W.J.Compressional intracontinental orogens: ancient and modern perspectives.Earth Science Reviews, Vol. 130, pp. 128-153.MantleGeodynamics
DS200512-0834
2005
Rainbird, R.Pehrsson, S.L., Berman, R.G., Rainbird, R., Davis, W., Skulski, Sanborn-Barrie, Van Breeman, Corrigan, TellaInterior collisional orogenesis related to supercontinent assembly: the ca. 1.9- 1.5 Ga tectonic history of the western Churchill province.GAC Annual Meeting Halifax May 15-19, Abstract 1p.Canada, SaskatchewanNuna, tectonics
DS201312-0694
2013
Rainbird, R.Pehrsson, S.J., Berman, R.G., Eglinton, B., Rainbird, R.Two Neoarchean supercontinents revisited: the case for a Rae family of cratons.Precambrian Research, Vol. 232, pp. 27-43.Canada, SaskatchewanKenoraland revised, Nunavutia
DS1990-1178
1990
Rainbird, R.H.Peterson, T.D., Rainbird, R.H.Tectonic and petrological significance of regional lamproite-minette volcanism in the The lon and Trans-Hudson hinterlands, Northwest TerritoriesGeol. Suv. of Canada Current Research Part C., Canadian Shield, Paper No. 90-1C, pp. 69-80Northwest TerritoriesLamproite-minette, Tectonics/petrology
DS1992-0689
1992
Rainbird, R.H.Heaman, L.M., LeCheminant, A.N., Rainbird, R.H.Nature and timing of Franklin igneous events, Canada: implications for a Late Proterozoic mantle plume and the break-up of LaurentiaEarth and Planetary Science Letters, Vol. 109, No. 1-2, March pp. 117-132GlobalMantle, Proterozoic
DS1992-1248
1992
Rainbird, R.H.Rainbird, R.H., Heaman, L.M., Young, G.Sampling Laurentia: detrital zircon geochronology offers evidence for an extensive Neoproterozoic river system originating from the Grenville orogenGeology, Vol. 20, No. 4, April pp. 351-354Victoria IslandShaler Group, Geochronology
DS1993-1276
1993
Rainbird, R.H.Rainbird, R.H.The sedimentary record of mantle plume uplift preceding eruption of the Neoporterozoic Natkusiak flood basalt.Journal of Geology, Vol. 101, pp. 305-18.Northwest Territories, Victoria IslandTectonics
DS1997-0942
1997
Rainbird, R.H.Rainbird, R.H., De Freitas, E.A.Stratigraphic evidence for the Siberia Laurentia connection and early Cambrian rifting: comments/reply.Geology, Vol. 25, No. 6, June pp. 569-572.Russia, Siberia, Anabar shield, Baffin Island, Victoria IslandStratigraphy, Rifting
DS1998-1203
1998
Rainbird, R.H.Rainbird, R.H., Stern R.A., Sukhorukov, V.I.uranium-lead (U-Pb) geochronology of Riphean sandstone and gabbro from southeast Siberia and its bearing on Laurentia-SiberiaEarth and Planetary Science Letters, Vol.164, No.3-4, Dec.30, pp.409-20.Russia, Siberia, LaurentiaGeochronology, Not specific to diamonds
DS2001-0959
2001
Rainbird, R.H.Rainbird, R.H., Ernst, R.E.The sedimentary record of mantle plume upliftGeological Society of America, Special Paper, Special Paper. 352, pp. 227-46.MantleRifting, tectonics, Plumes
DS2003-1123
2003
Rainbird, R.H.Rainbird, R.H., Hadlari, T., Aspler, L.B., Donaldson, J.A., Le Cheminant, A.N.Sequence stratigraphy and evolution of the Paleoproterozoic intracontinental BakerPrecambrian Research, Vol. 125, 1-2, pp. 21-53.NunavutBlank
DS200412-0782
2004
Rainbird, R.H.Hanmer, S., Sandeman, H.A., Davis, W.J., Aspler, L.B., Rainbird, R.H., Ryan, J.J., Relf, C., Peterson, T.D.Geology and Neoarchean tectonic setting of the Central Hearne supracrustal belt, Western Churchill Province, Nunavut, Canada.Precambrian Research, Vol. 134, 1-2, pp. 63-83.Canada, NunavutTectonics - not specific to diamonds
DS200412-1609
2003
Rainbird, R.H.Rainbird, R.H., Hadlari, T., Aspler, L.B., Donaldson, J.A., Le Cheminant, A.N., Peterson, T.D.Sequence stratigraphy and evolution of the Paleoproterozoic intracontinental Baker Lake and The lon Basins, western Churchill ProPrecambrian Research, Vol. 125, 1-2, pp. 21-53.Canada, NunavutGeology
DS1860-0952
1896
Rainconi, F.Rainconi, F.Cartes Commerciales et Minieres des Pays Sud-africainsParis:, 114P.Africa, South AfricaDiamond mining
DS201212-0576
2012
Rainer, t.Rainer, t., Davidson, P.The application of Raman spectroscopy in the study of fluid and melt inclusions.Zeitschrift der Deutschen Gesellschaft fur Geowissenschaften, Vol. 163, 2, pp. 113-126.TechnologyGraphite, diamond
DS1984-0486
1984
Raines, G.L.Marrs, R.W., Raines, G.L.Tectonic Framework of Powder River Basin, Wyoming and Montana Interpreted from Land sat Imagery.American Association Petrol. Geol., Vol. 68, No. 11, NOVEMBER PP. 1718-1731.United States, Montana, Wyoming, Rocky MountainsTectonics, Remote Sensing, Lineaments, Sedimentation
DS2002-1300
2002
Raines, G.L.Raines, G.L.Description and comparison of geologic maps with FRAGSTATS - a spatial statistics program.Computers and Geosciences, Vol.28, 2, pp. 169-77.GlobalComputer - FRAGSTATS
DS200512-1115
2005
Rainey, E.S.Van den Berg, A.P., Rainey, E.S., Yuen, D.A.The combined influence of variable thermal conductivity, temperature and pressure dependent viscosity and core mantle coupling on thermal evolutionPhysics of the Earth and Planetary Interiors, Vol. 149, 3-4, pp. 259-278.MantleGeothermometry
DS201412-0911
2014
Rainey, E.S.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, Vol. 41, 8, pp. 2746-2752.MantleGeothermometry
DS200512-1116
2005
Rainey, E.S.G.Van den Berg, A.P., Rainey, E.S.G., Yuen, D.A.Dependent viscosity and core mantle coupling on thermal evolution.Physics of the Earth and Planetary Interiors, Vol. 149, 3-4, April 15, pp. 259-278.MantleGeothermometry
DS201112-0839
2011
Rainey, E.S.G.Rainey, E.S.G., Kavner, A., Hernlund, J.Heat flow in the laser heated diamond anvil cell and the thermal conductivity of the lower mantle.Goldschmidt Conference 2011, abstract p.1689.Mantle3D
DS201412-0912
2014
Rainey, E.S.G.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S.G., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, Apr. 16 DOI: 10.1002/2014 GL059385MantleGeothermometry
DS201412-0913
2014
Rainey, E.S.G.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S.G., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, April 16, pp. 2746-2742.MantleGeothermometry
DS201412-0914
2014
Rainey, E.S.G.Tang, X., Ntam, M.C., Dong, J., Rainey, E.S.G., Kavner, A.The thermal conductivity of Earth's lower mantle.Geophysical Research Letters, Vol. 41, 8, pp. 2746-2752.MantleGeothermometry
DS1993-1277
1993
Rains, B.Rains, B., Shaw, J., Skoye, R., Sjogren, D., Kvill, D.Late Wisconsin subglacial megaflood paths in AlbertaGeology, Vol. 21, No. 4, April pp. 323-326.AlbertaGeomorphology, Glacial
DS2003-1339
2003
Rainsford, D.Stott, G., Rainsford, D.Interpreting the Precambrian under the Lowlands: implications for mineral explorationOntario Exploration and Geoscience Symposium, Dec. 8,9,10th., Abstracts p. 2. (1/8p.)Ontario, AttawapiskatMapping
DS200412-1933
2003
Rainsford, D.Stott, G., Rainsford, D.Interpreting the Precambrian under the Lowlands: implications for mineral exploration. GIS database - two maps 1:500,000Ontario Exploration and Geoscience Symposium, Dec. 8,9,10th., Abstracts p. 2. (1/8p.)Canada, Ontario, Attawapiskat, James Bay LowlandsMapping
DS1993-0478
1993
Rainville, J.Gagnon, G-Y., Rainville, J.A kimberlite discovery in the Temiscaminque areaQuebec Exploration Conference summaries held September 15-1th. Val d'Or, pp. 10-12QuebecTemiskaming area
DS1995-1538
1995
Raisanen, M.L.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.
DS1990-1156
1990
Raiser, S.Park, A.F., Raiser, S.Geology of the south western part of Tavani map area, 55 K 3, 4, 5, 6, District of Keewatin, northwest Territories.Geological Survey of Canada (GSC) Open File, No. 2265, 103p.Northwest TerritoriesGeology
DS1860-0692
1891
Raisin, C.A.Bonney, T.G., Raisin, C.A.Report on Some Rock Specimens from the Kimberley Diamond MinGeology Magazine , Dec. 3, Vol. 7, PP. 412-415.Africa, South Africa, Griqualand WestDiamond mines, mineralogy, petrology
DS1860-0883
1895
Raisin, C.A.Bonney, T.G., Raisin, C.A.Notes on the Diamond Bearing Rock of Kimberley, South Africa. the Kimberley Diamond Mines.Geology Magazine , Dec. 4, Vol. 2, PP. 496-502. Neues Jahrbuch f?r Mineralogie BD. 2, PP. 43Africa, South Africa, Cape ProvinceDiamond mines, mineralogy, petrology
DS1900-0310
1905
Raisin, C.A.Bonney, T.G., Raisin, C.A.The Microscopic Structure of Minerals Forming Serpentine And Their Relation to its History.Quarterly Journal of Geological Society, Vol. 61, PP. 690-714. ALSO. Proceedings Geological Society 1904-1905, P. 1Africa, South AfricaRelated Rocks
DS201808-1770
2018
Raisson, S.Mourot, Y., Roddaz, M., Dera, G., Calves, G., Kim, J-H., Charboureau, A-C., Mounic, S., Raisson, S.Geochemical evidence for large scale drainage reorganization in northwest Africa during the Cretaceous.Geochemistry, Geophysics, Geosystems, Vol. 19, 5, pp. 1690-1712.Africageomorphology

Abstract: West African drainage reorganization during Cretaceous opening of the Atlantic Ocean is deciphered here from geochemical provenance studies of Central Atlantic sediments. Changes in the geochemical signature of marine sediments are reflected in major and trace element concentrations and strontium?neodymium radiogenic isotopic compositions of Cretaceous sedimentary rocks from eight Deep Sea Drilling Project (DSDP) sites and one exploration well. Homogeneous major and trace element compositions over time indicate sources with average upper (continental) crust signatures. However, detailed information on the ages of these sources is revealed by neodymium isotopes (expressed as ?Nd). The ?Nd(0) values from the DSDP sites show a three?step decrease during the Late Cretaceous: (1) the Albian?Middle Cenomanian ?Nd(0) values are heterogeneous (-5.5 to ?14.9) reflecting the existence of at least three subdrainage basins with distinct sedimentary sources (Hercynian/Paleozoic, Precambrian, and mixed Precambrian/Paleozoic); (2) during the Late Cenomanian?Turonian interval, ?Nd(0) values become homogeneous in the deepwater basin (-10.3 to ?12.4), showing a negative shift of 2 epsilon units interpreted as an increasing contribution of Precambrian inputs; (3) this negative shift continues in the Campanian?Maastrichtian (?Nd(0)?=??15), indicating that Precambrian sources became dominant. These provenance changes are hypothesized to be related to the opening of the South and Equatorial Atlantic Ocean, coincident with tectonic uplift of the continental margin triggered by Africa?Europe convergence. Finally, the difference between ?Nd(0)values of Cretaceous sediments from the Senegal continental shelf and from the deepwater basins suggests that ocean currents prevented detrital material from the Mauritanides reaching deepwater areas.
DS1994-1384
1994
Raiswell, R.W.Plant, J.A., Raiswell, R.W.Mentions of diamond on p. 107, 190, 192, 202, 208, 224 in DrainageGeochemistry.Handbook of Exploration Geochemistry, Vol. 6, excerptsGlobalGeochemistry, Diamonds
DS200612-1094
2006
Raita, T.SSTWG.Plomerova, J., Babuska, V., Vecsey, L., Kozlovskaya, E., Raita, T.SSTWG.Proterozoic Archean boundary in the mantle lithosphere of eastern Fennoscandia as seen by seismic anisotropy.Journal of Geodynamics, Vol. 41, 4, May pp. 400-410.Europe, FennoscandiaGeophysics - seismics
DS1999-0773
1999
Raitala, J.Vishnevskii, S.A., Palchik, N.A., Raitala, J.Diamonds in impactites of the Lappajarvi impact craterRussian Geology and Geophysics, Vol. 40, No. 10, pp. 1487-90.FinlandImpact crater
DS2003-1124
2003
Raith, J.G.Raith, J.G., Cornell, D.H., Frimmel, H.E., De Beer, C.H.New insights into the geology of the Namaqua tectonic province, South Africa, from ionJournal of Geology, Vol. 111, 3, pp. 347-66.South AfricaTectonic - zone, Geochronology
DS200412-1610
2003
Raith, J.G.Raith, J.G., Cornell, D.H., Frimmel, H.E., De Beer, C.H.New insights into the geology of the Namaqua tectonic province, South Africa, from ion probe dating of detrital and metamorphicJournal of Geology, Vol. 111, 3, pp. 347-66.Africa, South AfricaTectonic - zone Geochronology
DS2001-0977
2001
Raith, M.M.Rickers, K., Mezger, K., Raith, M.M.Evolution of the continental crust in the Proterozoic eastern Gnats belt, new constraints for Rodinia reconstPrecambrian Research, Vol. 112, No. 3-4, Dec. 10, pp. 183-210.IndiaGeochronology - Sm neodymium Rb Sr lead lead, Gondwana
DS200612-1450
2006
Raith, M.M.Upadhyay, D., Raith, M.M.Petrogenesis of the Kunavaram alkaline complex and the tectonothermal evolution of the neighbouring Eastern Ghats Belt granulites SE India.Precambrian Research, in press - availableIndiaAlkaline rocks, geochemistry, geochronology
DS200612-1451
2006
Raith, M.M.Upadhyay, D., Raith, M.M., Mezger, K., Bhattacharya, A., Kinny, P.D.Mesoproterozoic rifting and Pan African continental collision in SE India: evidence from the Khariar alkaline complex.Contributions to Mineralogy and Petrology, Vol. 141, 4, April pp. 434-456.Asia, IndiaTectonics
DS200612-1452
2006
Raith, M.M.Upadhyay, D., Raith, M.M., Mezger, K., Hammerschmidt, K.Mesoproterozoic rift related alkaline magmatism at Elchuru, Prakasam alkaline province, SE India.Lithos, Vol. 89, 3-4, July pp. 447-477.IndiaBasanites, Tectonics, magmatism, Eastern Gnats Belt
DS200412-1611
2004
Raj, K.G.Raj, K.G., Nijajunappa, R.Major lineaments of Karnataka State and their relations to seismicity: a remote sensing based analysis.Journal Geological Society of India, Vol. 63, 4, pp. 430-439.IndiaTectonics, geophysics - seismics
DS2002-0010
2002
Rajagopalan, G.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
DS1989-0559
1989
Rajakuma.., V.Gupta, S.K., Rajakuma.., V., Grieveso..P.The influence of weathering on the reduction of ilmenite with carbonMetall. T-B., Vol. 20, No. 5, October pp. 735-745. AX896GlobalIlmenite -general, Weathering
DS1990-1210
1990
Rajamani, K.Rajamani, K., Herbst, J.A.Control '90-mineral and metallurgical processingAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Book, 600p. approx. $ 70.00GlobalMineral processing, Control 90 - from meeting presentations
DS1993-1278
1993
Rajamani, V.Rajamani, V., Balakrishnan, S., Hanson, G.N.Komatiite genesis: insights provided by iron-magnesium exchange equilibriaJournal of Geology, Vol. 101, No. 6, November pp. 809-819IndiaKomatiite, Archean, Kolar Schist Belt, Genesis
DS1999-0041
1999
Rajamani, V.Balakrishnan, S., Rajamani, V., Hanson, G.N.uranium-lead (U-Pb) ages for zircon and titanite from the Ramagiri area, evidence for accretionary origin ....Late ArcheanJournal of Geology, Vol. 107, No.1, Jan. pp. 69-86.India, South IndiaGeochronology, Dharwar Craton
DS201112-0170
2011
Rajamanickam, G.V.Chandrasekar, N., Sheik Mujabar, P., Rajamanickam, G.V.Investigation of heavy mineral deposits using multispectral satellite data.Journal of the Geological Society, Vol. 168, 8, pp. 8641-8655.TechnologyHyperspectral
DS1975-1191
1979
Rajamaran, S.Rajamaran, S., et al.Stream Sediment Surveys in Kelyandurg Area, Anantapur District for Locating Kimberlite Pipes.India Geological Survey Program Report, FOR 1978-1979India, Andhra PradeshDiamond Prospecting, Geochemistry
DS202009-1627
2020
Rajan, S.Fareeduddin, Pant, N.C., Gupta, S., Chakraborty, P., Sensarma, S., Jain, A.K., Prasad, G.V.R., Srivastava, P., Rajan, S., Tiwari, V.M.The geodynamic evolution of the Indian subcontinent - an introduction.Episodes, Vol. 43, 1, pp. 8p.Indiacarbonatites
DS2000-0389
2000
Rajaram, M.Harikumar, P., Rajaram, M., Balakrishnan, T.S.Aeromagnetic study of peninsular IndiaProceedings Indian Academy of Science, Vol. 109, No. 3, Sept pp. 381-91.IndiaGeophysics - magnetics
DS2002-0032
2002
Rajaram, M.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
DS200412-0031
2003
Rajaram, M.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
Rajaram, M.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
Rajaram, M.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
Rajaram, M.Rajaram, M., Anand, S.P.Aeromagnetic signatures of Precambrian shield and suture zones of Peninsular India.Geoscience Frontiers, in press availableIndiaGeophysics
DS1992-1249
1992
Rajaram, V.Rajaram, V.Changing roles of the geologist and engineer...(communication)The Professional Geologist, August pp. 10GlobalProfessional registration, Comments
DS1960-1195
1969
Rajaraman, S.Rajaraman, S., Deshpande, M.L.Report on the Preliminary Investigation for Diamonds in The banganapalle Conglomerate and Tungabhadra Krishna River Gravels in Parts of Kurnool and Mahaboolonagar Districts.India Geological Survey Program Report, FOR 1967-1968India, Andhra PradeshDiamond Prospecting
DS1970-0372
1971
Rajaraman, S.Narayanaswami, S., Hunday, A., Rajaraman, S., Deshpande, M.L.The Current Exploration for Diamond in Different Host Rocks of Andhra Pradesh by the Geological Survey of India.India Geological Survey Miscellaneous Publishing, No. 19, PP. 42-48.IndiaProspecting
DS1970-0809
1973
Rajaraman, S.Rajaraman, S., Rao, A.V.K.Report on the Investigation for Diamond Carries Out in Pipe-1 in Wajrakarur, Anantapur District, Andhra Pradesh.India Geological Survey Program Report, FOR 1968-1973India, Andhra PradeshDiamond Prospecting
DS1975-0844
1978
Rajaraman, S.Rajaraman, S., Deshpande, M.L.Banganapalle Diamondiferous Conglomerates in Kurnool District, A.p.Indian Minerals, Vol. 32, No. 3, PP. 33-43.India, Andhra PradeshGeology
DS1975-0845
1978
Rajaraman, S.Rajaraman, S., Deshpande, M.L.Status of Assessment of Diamond Resources in Andhra PradeshIndian Minerals, Vol. 32, No. 2, PP. 39-45.India, Andhra PradeshMineral Resources
DS1975-1192
1979
Rajaraman, S.Rajaraman, S.A Short Note on the William son Diamond Mines, Mwadui, Shinyanga Region, Tanzania.Indian Minerals, Vol. 33, No. 1, P. 52.Tanzania, East AfricaHistory
DS1980-0283
1980
Rajaraman, S.Rajaraman, S., et al.Diamond Deposits of Transported Origin in Andhra PradeshTranscript of Paper From Diamond Seminar, Bombay, 11P.India, Andhra PradeshDiamond Occurrences
DS1975-1193
1979
Rajarman, S.Rajarman, S.A Short Note on the William son Diamond Mine, Mwadui, Shinyanga Region, Tanzania.Indian Minerals, Vol. 33, No. 1, P. 52.Tanzania, East AfricaGeology
DS200612-0922
2006
Rajasekar, R.P.Mishra, D.C., Kumar, V.V., Rajasekar, R.P.Analysis of airborne magnetic and gravity anomalies of peninsular shield, India integrated with seismic, magnetotelluric and gravity anomalies.Gondwana Research, Vol. 10, Aug.1-2, pp. 6-17.India, Africa, MadagascarGeophysics - magnetics, gravity
DS200712-0866
2007
Rajendra Prasad, B.Rajendra Prasad, B., Kesava Rao, G., Mall, D.M., Koteswarar Rao, P., Raju, S., Reddy, SridherTectonic implications of seismic reflectivity pattern observed over the Precambrian southern granulite terrain, India.Precambrian Research, Vol. 153, 1-2, pp. 1-10.IndiaGeophysics - seismics
DS1999-0576
1999
Rajendran. K., C.P.Rajendran. K., C.P.Seismogenesis on the stable continental interiors: an appraisal based on two examples from India.Tectonophysics, Vol. 305, No. 3, May 10, pp. 355-70.IndiaGeophysics - seismics, Craton
DS200412-2185
2003
Rajesh, H.M.Yoshida, M., Jacobs, J., Santosh, M., Rajesh, H.M.Role of Pan African events in the Circum East Antarctic Orogen of East Gondwana: a critical overview.Proterozoic East Gondwana: Supercontinent assembly and Breakup. Ed. Yoshida , Geological Society of London Spe, No. 206, pp. 57-76.AntarcticaPlume, tectonics
DS200812-0436
2008
Rajesh, H.M.Gutzmer, J., Harding, C.H., Beukes, N.J., Huizenga, J.M., Rajesh, H.M.Continental rifting, alkaline magmatism and the formation of high grade iron ores along the western margin of the Kaapvaal Craton, South Africa.GSSA-SEG Meeting Held July, Johannesburg, 33 Power point slidesAfrica, South Africa, Namibia, BotswanaMagmatism
DS201212-0461
2012
Rajesh, K.Melluso, L., Rajesh,K., Srivastava, C.M., Petrone, V., Guarino, V., Sinha, A.K.Mineralogy, magmatic affnity and evolution of the Early Cretaceous alkaline complex of Jasra, Shillong Plateau, northeastern India.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractIndiaDeposit - Jasra
DS200812-0773
2008
Rajesh, M.Mukhopadhyay, R., Rajesh, M., De, S., Chakraborty, B., Jauhan, P.Structural highs on the western continental slope of India: implications for regional tectonics.Geomorphology, Vol. 96, 1-2, pp. 48-61.IndiaTectonics
DS200412-1613
2004
Rajesh, R.S.Rajesh, R.S., Mishra, D.C.Lithospheric thickness and mechanical strength of the Indian Shield.Earth and Planetary Science Letters, Vol. 225, 3-4, pp. 319-328.IndiaTectonics
DS201801-0051
2017
Rajesh, S.Rajesh, S., Pradeepkumar, A.P.Carbonatite occurrences in Munnar area, Kerala, southern India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 36-37.Indiacarbonatites

Abstract: Carbonatites, usually associated with alkaline complexes and emplaced within continental rifting environment, are the rarest of all the igneous rocks. Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of REEs (Long et.al. 2010). Carbonatites are defined by the International Union of Geological Sciences (IUGS) system of igneous rock classification as having more than 50 modal percent primary carbonate minerals, such as calcite, dolomite, and ankerite, and less than 20 percent SiO2 (Le Maitre, 2002). Southern India has several carbonatite occurrences and the alkaline complex of Munnar in southern India comprises of an alkali granite plutons with minor patches of charnockite, syenite and carbonatite emplaced within Precambrian gneisses (Nair et.al., 1983, 1984; Santosh et.al., 1987, Nair et.al., 1984). Gneissic layering and foliation are apparent in all but the least deformed granitic rocks in the study area. The Munnar granite body is situated in the western part of the Madurai block in Southern Granulite Terrane (SGT) of Peninsular India, within the newly defined Western Madurai Domain. The complex is spatially related to the intersection zone of Karur-Kambam-Painavu-Trissur lineament. The alkali granite of the complex has been dated at 740±30 my (Odom, 1982) and 804±6 Ma (Brandt et. al., 2014). Present study deals with examining the nature of the carbonatites and takes a relook at its major and REE contents, and for the first time, looks at the stable isotope signatures of these rocks, in an attempt to check whether these rocks are indeed carbonatites. The geology and geochemistry of the rock types in and around Munnar area have been mapped with special focus on carbonatites. Extensive field mapping was carried out and a base map was prepared and all the geological and structural features were recorded in the base map. Intra- and inter-relationships of various rock units were examined. Field photographs of interesting geological features have been recorded. Carbonatites in Munnar area are exposed as two minor patches. The one which occurs towards north of the Munnar town and is seen as patches, lens and veins of 30 cm to 1 m thickness, cutting coarse grained syenite which occurs as a NW- SE along a body. Exposures are found about 15 km from Munnar on the Udumalpet road. The second exposure occurs towards the east of the Munnar town, near at the Ellapatty estate 24 km from Munnar on the road to top station where coarse grained cabonatites occurs as lenticular bodies up to 1.5 m thick within granite. In both the localities, the carbonatite bodies show sharp and discordant margins with absence of any pseudomorphs within them. Fenitisation is characterised by the development of pink K-feldspar megacrystals in the country rock at the contact. The carbonatites are fresh and homogenous and represent two varieties. A coarse grained holocrystalline type and yellowish calcite crystals constituting 90% of the rock, with pyroxene apatite and magnetite correspond to sovite (Streckeisen, 1979). The second variety which contains highly coarse calcite crystals (up to 1 cm) and associated dolomite with mafic minerals constituting 30% of the rock corresponds to alvikite. The sovite exhibits an interlocking crystals mosaic of calcite in thin section. The calcite crystals of alvikite show exsolution blebs of dolomite. The major mafic component in both varieties is aegirine-augite which forms euhedral- subhedral laths (Santosh et al., 1984). The opaque phase is dominantly magnetite. Rarely phlogopite, biotite and minor laths of albite are also noted, small crystals of euhedral apatite are found occluded in calcite grain although alkaline complexes with carbonatite of Munnar devoid of related mafic differentiates like gabbros or lamprophyres may be considered unique. The immiscibility of carbonatitic and alkalic silicate liquids can be physically explained as the separation of a less viscous carbonate liquid from a more viscous polymerized silicate phase. The carbonate liquid would be lower in density because of higher content of H2O and this contrast in density could cause phase separation due to earth’s gravitational field alone (Moller et al., 1980). The pre-requisite to establish separation of immiscible silicate-saturated carbonatite liquid and the associated carbonate-saturated silicate melt is achieved as follows; Large-scale volatile outgassing occurs during crustal wrapping and distention prior to rifting which trigger mantle degassing (Bailey, 1974). An imprint of such large-scale volatile influx is recognised in the Kerala region (Nair et al., 1984). Rapid ascent volatiles enriched in CO2 liberated from the mantle cause partial melting at shallower levels of the mantle.
DS202009-1630
2020
Rajesh, S.Hegner, E., Rajesh, S., Willbold, M., Muller, D., Joachimiski, M., Hofmann, M., Linnemann, U., Zieger, J., Pradeepkumar, A.P.Sediment derived origin of the putatative Munnar carbonatite, South India.Journal of Asian Earth Science, Vol. 200, 104432, 18p. PdfIndiadeposit - Munnar

Abstract: Metacarbonate assemblages in high-grade metamorphic terranes often pose challenges when trying to distinguish between mantle-derived carbonatite and sedimentary carbonate protoliths. We present a study of granulite-facies metacarbonate samples of the putative Munnar carbonatite described as decimeter-thick dikes and veins, and layers of a meter-thick metacarbonate and calc-silicate assemblage, respectively. Thin sections of the metacarbonate dike samples show absence of pyrochlore and ubiquitous scapolite, titanite, wollastonite, and detrital zircons are compatible with impure limestone protoliths. Nd and Sr isotope compositions indicate protoliths with Paleoproterozoic crustal residence times which contrast the mantle sources of Indian and global carbonatites. Trace-element patterns display the characteristics of upper crust, and Ce- and Y-anomalies in a number of samples suggest protolith formation under marine conditions. Carbon and oxygen isotope compositions of the metacarbonate samples interlayered with calc-silicate rocks are similar to those in marine limestone. The metacarbonate dikes, however, show mantle-like compositions which are interpreted as reflecting equilibration with mantle-derived CO2 during granulite-facies metamorphism. The dikes yielded a U-Pb zircon crystallization age of 1020 ± 70 Ma and a cross-cutting quartz syenite, thought to be cogenetic, a magmatic age of 620 ± 35 Ma; the hosting gneiss provided a magmatic age of 2452 ± 14 Ma. We conclude that the layered metacarbonate and calc-silicate rocks represent a former marine limestone and marl sequence and the metacarbonate dikes and veins small-volume melts of crust-derived carbonate-rich sediment.
DS200612-1122
2006
Rajesh, V.J.Rajesh, V.J., Arai, S.Baddelyite apatite spinel phlogopite (BASP) rock in Achankovil shear zone, South India, as a probable cumulate from melts of carbonatite affinity.Lithos, Vol.90, 1-2, August pp. 1-18.IndiaCarbonatite
DS201012-0608
2010
Rajesh, V.J.Rajesh, V.J., Arai, S., Santosh, M., Tamura, A.LREE rich hibonite in ultrapotassic rocks in southern India.Lithos, Available in press formated 11p.IndiaAlkalic
DS1993-1279
1993
Rajlich, P.Rajlich, P.Riedel shear: a mechanism for crenulation cleavageEarth Science Reviews, Vol. 34, pp. 167-195GlobalStructure -reidel shears, Review
DS200812-0323
2008
RajuEriksson, P.G., Banerjee, S., Nelson, D.R., Rigby, M.J., Catuneanu, O., Sarkar, S., Roberts, R.J., Ruban, Mtimkulu, RajuA Kaapvaal Craton debate: nucleus of an early small supercontinent or affected by an enhanced accretion event?Gondwana Research, In press available, 82p.Africa, South AfricaSupercontinents
DS2003-1147
2003
Raju, A.N.Reddy, K.S., Raju, A.N.The physical and textural characteristics of termite mounds from Podili and TalupulaJournal of the Geological Society of India, Vol. 61, 6, June, pp. 693-98.IndiaBlank
DS200412-1644
2003
Raju, A.N.Reddy, K.S., Raju, A.N.The physical and textural characteristics of termite mounds from Podili and Talupula areas, Andhra Pradesh.Journal of the Geological Society of India, Vol. 61, 6, June, pp. 693-98.IndiaGeomorphology - not specific to diamonds
DS2003-1125
2003
Raju, D.C.Raju, D.C.LIMAT: a computer program for least squares inversion of magnetic anomalies overComputers and Geosciences, Vol. 29, 1, pp. 91-98.GlobalComputer - program
DS2001-0960
2001
Raju, D.C.I.Raju, D.C.I., Thakur, K.S., Shrivastava, S.K., Sambandam, S.T., Khoitpal, A.S.Ground evaluation of aeromagnetic and spectrometric and other integrated dat a inIndia Geological Survey Records, No. 135, 2, p. 129-131.IndiaNews item - diamond discoveries
DS200612-1294
2001
Raju, D.C.L.Shrivastava, S.K., Roy, A., Thakur, K.S., Raju, D.C.L., Muthuraman, K.Integrated approach for locating kimberlites in eastern parts of Bastar Craton in Chhattisgarh and Orissa States.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 615-621.India, Chhattisgarh, OrissaDiamond exploration - geochemistry
DS1975-1194
1979
Raju, K.C.C.Raju, K.C.C., Kareemuddin, M.D., Prabhakara, R.P.Operation AnantapurIndia Geological Survey Miscellaneous Publishing, No. 47, PP. 12-16.India, Andhra PradeshBlank
DS1970-0371
1971
Raju, K.K.Narasimham, C.V., Raju, K.K.Photogeologic Studies in and Around Panna, District, A.pI.p.i. Dehra Dun Unpubl. Report, India, Andhra PradeshPhotgeology
DS200812-0936
2008
Raju, K.N.Rao, D.V.S., Balaram, V., Raju, K.N., Sridhar, D.N.Paleoproterozoic boninite like rocks in an intracratonic setting from northern Bastar Craton, central India.Journal of the Geological Society of India, Vol. 27, 3, pp. 373-380.IndiaBoninites
DS1991-1394
1991
Raju, M.V.B.Raju, M.V.B., Misra, G.B.An evaluation of the undiscovered mineral resources of India based on the concept of unit regional valueMath. Geol, Vol. 23, No. 6, August pp. 841-852IndiaGeostatistics, Mineral resources
DS2003-1212
2003
Raju, P.S.Sarkar, D., Kumar, M.R., Saul, J., Kind, R., Raju, P.S., Chadha, R.K., ShuklaA receiver function perspective of the Dharwar craton ( India) crustal structureGeophysical Journal International, No. 154, 1, pp. 205-211.IndiaBlank
DS200412-1731
2003
Raju, P.S.Sarkar, D., Kumar, M.R., Saul, J., Kind, R., Raju, P.S., Chadha, R.K., Shukla, A.K.A receiver function perspective of the Dharwar craton ( India) crustal structure.Geophysical Journal International, No. 154, 1, pp. 205-211.IndiaGeophysics - seismics
DS200512-0588
2004
Raju, P.S.Kumar, M.R., Raju, P.S., Devi, E.U., Saul, J., Ramesh, D.S.Crustal structure variations in northeast India from converted phases.Geophysical Research Letters, Vol. 31, 17, Sept. 16, L17605IndiaTectonics
DS200512-0889
2005
Raju, P.S.Ramesh, D.S., Kumar, M.R., Devi, E.U., Raju, P.S., Yaun, X.Moho geometry and upper mantle images of northeast India.Geophysical Research Letters, Vol. 32, 14, July 28, L14301IndiaGeophysics - seismics
DS200612-1312
2006
Raju, P.S.Singh, A., Kumar, M.R., Raju, P.S., Ramesh, D.S.Shear wave anisotropy of the northeast Indian lithosphere.Geophysical Research Letters, Vol. 33, 16, August 28, L16302.IndiaGeophysics - seismics
DS200712-0866
2007
Raju, S.Rajendra Prasad, B., Kesava Rao, G., Mall, D.M., Koteswarar Rao, P., Raju, S., Reddy, SridherTectonic implications of seismic reflectivity pattern observed over the Precambrian southern granulite terrain, India.Precambrian Research, Vol. 153, 1-2, pp. 1-10.IndiaGeophysics - seismics
DS201805-0971
2018
Raju, V.V.Phani, R., Raju, V.V., Srinivas, M.Petrological and geochemical characteristics of a shoshonitic lamprophyre, Sivarampet, Wajrakarur, kimberlite field, southern India.Journal of Applied Geology and Geophysics (IOSR), Vol. 6, 2, pp. 55-69. pdfIndiashoshonite

Abstract: Field geological, petrographic and geochemical characteristics of a lamprophyre intrusion, presumably of plug-type, at Sivarampet (SPL), occurring within the Wajrakarur kimberlite field (WKF) to the west of Cuddapah basin, are presented and discussed. The lamprophyre intrusion occurs as brecciated outcrop with angular country rock granitoid clasts and also it forms stringers/veinlets within the granitic country rock. The melanocratic rock displays panidiomorphic/porphyritic texture, typical of lamprophyres, comprising clinopyroxene, biotite, phlogopite set in a groundmass of feldspar, magnetite and spinel. Plagioclase is dominant feldspar. The K2O/Na2O ratio ranges from 1.55 to 1.89 wt %, making it distinctly potassic and brings out its shoshonitic behaviour. The fractionated chondrite normalised patterns of REE (with average (La/Yb)N= 21.01 ppm) implies involvement of an enriched mantle source while depleted values of Nb, Hf, Th and U concentrations indicate prevalence of subducted component in the mantle source. The concentrations of Rb, Sr and Ba indicate presence of phlogopite in the source. Based on the mineral assemblages, the SPL can be classified as calc-alkaline variety; however, its geochemistry shows characteristics of both alkaline and calc-alkaline varieties. The moderate Mg# (52 to 55.6) and low concentration of Ni (95.61 to 112.4 ppm) in the bulk rock indicate a low degree of partial melting of magmatic fluid from enriched asthenospheric mantle which underwent fractionation of olivine and pyroxene, subsequently producing lamprophyre magma. Recent discovery of diamonds in shoshonitic lamprophyres of Canada, appeals further investigations on diamondiferous nature of similar rock types of the WKF.
DS201805-0972
2017
Raju, V.V.N.Phani, R., Raju, V.V.N.A new kimberlite pipe in Balkamthota Vanka, Pennahobilam, Anantapur district, Andhra Pradesh, India. Field aspects and preliminary investigations.Periodico di Mineralogia, Vol. 86, pp. 213-228. pdfIndiadeposit - Balkamthota Vanka

Abstract: Systematic closely spaced geological traverses conducted in the year 2010, in Lattavaram Kimberlite Cluster (LKC) of Anantapur district, Andhra Pradesh, India, have led to the discovery of a new kimberlite pipe outcrop in the river bed of Balkamthota Vanka (name of the stream used by local farmers) at its confluence with Penna River, close to Pennahobilam. This new pipe occurs at a distance of 1.5 km in NE direction to hitherto reported pipes-5 and 13 occurring at Muligiripalli and Tummatapalli respectively in the LKC of the Wajrakarur Kimberlite Field (WKF). With this pipe, the total number of kimberlite pipes in the WKF raises to 48, considering all the kimberlites discovered by various public and private organizations so far. Preliminary petrography, geochemistry, petrogenetic aspects and diamond prospectivity of the new occurrence have been presented here. Mineralogically, the kimberlite constitutes olivine macrocrysts, serpentinsed olivine psuedomorphs with xenocrystic ilmenite, phlogopite, perovskite, magnetite, Cr-diopside, garnet along with calcite veins. The kimberlite is classified as hypabyssal macrocrystic calcite- phlogopite kimberlite. Mineralogically, the new kimberlite pipe appears as archetypal Group- I kimberlite however, geochemically; the kimberlite shows character of both Group- I and II varieties, more close to lamproitic character. Although it is too early to comment, based on limited analyses carried out in this study, the diamond potentiality of this pipe is not encouraging; it is noteworthy that it highly warrants detailed investigations involving bulk rock geochemistry and drilling to assess its definite geochemical status, petrogenesis and diamond potentiality.
DS1970-0392
1971
Rake, A.Rake, A.Smuggling Hits Tanzania Diamond IndustryAfr. Dev., MARCH, PP. 14-15.Tanzania, East AfricaHistory
DS201512-1920
2015
RakeshGokhale, M., Madhura, Somani, R., RakeshFullerenes: chemistry and its applications.Mini-Reviews in Organic Chemistry, Vol. 12, 4, pp. 355-366.TechnologyFullerenes

Abstract: Fullerenes being allotropes of carbon, have been considered as new class of molecules. Unlike diamond and graphite, this is made up of hollow carbon cage structure. The idea of spheroidal cage structures of C60 arose from construction of geodesic domes made by renowned architect Buckminster Fuller. Although fullerenes have low solubility in physiological media they finds promising biological applications. The photo, electrochemical and physical properties of C60 and other fullerene derivatives finds applications in medical fields. The ability of fullerenes to fit inside the hydrophobic cavity of HIV proteases makes them potential inhibitor for substrates to catalytic active site of enzyme. It possesses radical scavenging and antioxidant property. At the same time, when it exposed to light it can form singlet oxygen in high quantum yields which with direct electron transfer from excited state of fullerenes and DNA bases finally results in cleavage of DNA. The fullerenes are also used as a carrier for gene and drug delivery system. The associated low toxicity of fullerenes is sufficient to attract the researchers for investigation of these interesting molecules.
DS201502-0102
2015
Rakevich, A.L.Skuzovatov, S.Yu., Zedgenizov, D.A., Rakevich, A.L., Shatsky, V.S., Martynovich, E.F.Multiple growth events in diamonds with cloudy Micro inclusions from the Mir kimberlite pipe: evidence from the systematics of optically active defects.Russian Geology and Geophysics, Vol. 56, 1, pp. 330-343.RussiaDeposit - Mir
DS201507-0328
2015
Rakevich, A.L.Mironov, V.P., Rakevich, A.L., Stepanov, F.A., Emelyanova, A.S., Zedgenizov, D.A., Shatsky, V.S., Kagi, H., Martynovich, E.F.Luminescence in diamonds of the Sao Luiz placer ( Brazil).Russian Geology and Geophysics, Vol. 56, pp. 729-736.South America, BrazilDiamond luminesence
DS201603-0423
2016
Rakevich, A.L.Stepanov, F.A., Mironov, V.P., Rakevich, A.L., Shatsky, V.S., Zedgenizov, D.A., Martynovich, E.F.Red luminescence decay kinetics in Brazilian diamonds. ( Juina)Bulletin of the Russian Academy of Sciences. Physics ** IN ENG, Vol. 80, 1, pp. 74-77.South America, BrazilDiamond formation

Abstract: Luminescence kinetics in the temperature range of 80 480 K and the red region of the spectrum is studied for Brazilian diamonds. Components with decay time constants of 23 and 83 ns are observed at room temperature after being excited by laser radiation with wavelengths of 375 and 532 nm, which differs considerably from the data published earlier for the luminescence kinetics of NV 0- and NV -centers.
DS201707-1366
2017
Rakevich, A.L.Shuzovatov, S.Y., Zedgenizov, D.A., Rakevich, A.L.Spectroscopic constraints on growth of Siberian mixed habit diamonds.Contributions to Mineralogy and Petrology, Vol. 172, pp. 46-64.Russiadeposit -Mir, Internationalnaya, Udachnaya, Nyurbinskaya

Abstract: Notable within-crystal variability of mineralogical and geochemical properties of single natural diamonds are commonly attributed to changing chemistry of parental fluids, sources of carbon and redox conditions of diamond precipitation. A distinct type of compositional heterogeneity (mixed-habit structure) is well-known to occur in diamonds as well as in many other minerals due to purely “structural” reasons that are unequal crystal chemistry of crystallographically different faces and selective absorption and fractionation of impurities between adjacent growth pyramids. Based on the combined cathodoluminescence, Fourier-transformed infrared spectroscopy and photoluminescence spectroscopy, study of nine diamond crystals with different growth histories and external morphology, but all showing mixed-habit patterns at different growth stages, we show that mixed-diamonds may grow in closed system conditions or with a slowly decreasing growth rate from a media with a much lower impurity content than previously thought. Intracrystal nitrogen distribution seems to be a function of growth rate even in the cases of unusual impurity partitioning between growth sectors. Generally poor with IR-active hydrogen at moderate nitrogen aggregation parameters, studied diamonds likely resemble the low hydrogen content from the growth medium that, for cubic diamonds, was typically suggested hydrogen-rich and a crucial factor for growth of cubic and mixed-habit diamonds. We also show that mixed-habit diamond growth may occur not only in peridotitic suite but also in an extended field of geochemical affinities from high-Ni to low-Ni or maybe even Ni-free environments, such as pyroxenitic or eclogitic.
DS201909-2086
2019
Rakhamanova, M.I.Shatsky, V.S., Nadolinny, V.A., Yuryeva, O.P., Rakhamanova, M.I., Komarovskikh, A.Yu.Features of the impurity composition of diamonds from placers of the northeastern Siberian craton.Doklady Earth Sciences, Vol. 486, 2, pp. 644-646.Russia, Siberiadiamond morphology

Abstract: Diamond crystals from the Istok (25 crystals) and Mayat (49 crystals) placers were studied using the EPR, IR, and luminescence methods. The total content of impurity nitrogen in forms of A, B, and C (P1) centers ranges from 50 to 1200 ppm. According to the EPR spectroscopy, the presence of nitrogen C (P1), N3V and nitrogen-titanium OK1, N3, NU1 impurity centers was established in the investigated crystals. For 18 crystals from the Istok placer, the N3 nitrogen-titanium center was observed in the EPR spectra, but in the luminescence spectra there was no 440.3 nm system, which was previously attributed to the manifestation of the N3 defect. It is more likely that the nitrogen-titanium N3 EPR center corresponds to the electron-vibrational system 635.7 nm, which is observed in the luminescence spectra of these crystals. Crystals from the Istok placer contain the OK1, N3, and NU1 centers, but luminescence attributed to the oxygen-containing centers is absent in the region of 610-670 nm. For the Mayat placer crystals, the reverse situation was observed. The luminescence ascribed to the oxygen-containing centers was detected for 17 crystals, but there were no OK1, N3, and NU1 centers according to the EPR and luminescence. This result contradicts the arguments of a number of authors about the oxygen nature of these defects. For 5 crystals from the Mayat placer, the nickel impurity was registered. This indicates the presence of ultrabasic paragenesis diamond crystals in this placer.
DS1984-0782
1984
Rakhmania, A.V.Yakolev, E.N., Voronov, O.A., Rakhmania, A.V.Synthesis of Diamonds from HydrocarbonsSoviet Journal of Superhard Materials, Vol. 6, No. 4, pp. 9-12RussiaDiamond Morphology
DS1999-0577
1999
Rakhmania, A.V.Rakhmania, A.V., Yakovlev, E.N.Experimental modeling of the natural synthesis of polycrystalline diamondGeochemistry International, Vol. 37, No. 7, July pp. 678-82.GlobalDiamond morphology
DS1987-0820
1987
Rakhmanina, A.V.Yakovlev, E.N., Voronov, O.A., Rakhmanina, A.V.Polycrystalline diamond aggregates obtained by using hydrocarbons.(Russian)Sverktverd. Mater.(Russian), No. 2, pp. 3-5GlobalDiamond synthesis
DS200712-0223
2007
Rakhmanina, A.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
DS200712-0290
2006
Rakhmaninia, A.Ekimov, E., Sidorov, V., Rakhmaninia, A., Melnik, N., Timofeev, M., Sadykov, R.Synthesis, structure and physical properties of boron doped diamond.Inorganic Materials, Vol. 42, 11, Nov. pp. 1198-1204.TechnologyDiamond mineralogy
DS202010-1852
2020
Rakhmanova, M.Komarovskikh, A., Rakhmanova, M., Yuryeva, O., Nadolinny, V.Infrared, photoluminescence, and electron paramagnetic resonance characteristic features of diamonds from Aikhal pipe, (Yakutia).Diamond & Related Materials, Vol. 109, 108045, 9p. PdfRussiadeposit - Aikhal

Abstract: The diversity of the defects in the collection (50 samples) of diamonds from the Aikhal pipe (Yakutia) has been studied with IR, PL, and EPR spectroscopy. The specific features of crystals have been established; the obtained information leads to the discussion about the diamond formation and growth conditions. One of the specific features observed is a high concentration of platelets. According to the platelet behavior, most of the crystals are regular suggesting the growth temperature to be 1100-1200 °C. The concentrations of A and B defects have been evaluated and the same temperature conditions have been obtained according to the Taylor diagram. Using the EPR spectroscopy, the C and N3V centers have been found in many crystals suggesting the aggregation of nitrogen during residence in the mantle at high temperatures. An interesting feature has been observed in the PL spectra. For most crystals, the spectrum with ZPL at 563.5 nm is very intensive. The structure of the observed defect is remaining unknown, the spectrum disappears as a result of annealing at 600 °C indicating the interstitial-vacancy annihilation mechanism.
DS201212-0507
2012
Rakhmanova, M.I.Nadolinny, V.A., Yuryeva,O.P., Rakhmanova, M.I., Shatsky, V.S., Palyanov, Y.N., Kupriyanov, I.N., Zedgenizov, D.A., Ragozin, A.L.Distribution of OK1, N3 and NU1 defects in diamond crystals of different habits.European Journal of Mineralogy, Vol. 24, 4, pp. 645-650.TechnologyDiamond morphology
DS201412-0721
2014
Rakhmanova, M.I.Rakhmanova, M.I., Nadolinny, V.A., Yuryeva, O.P., Pokhilenko, N.P.Pecularities of nitrogen impurity aggregation in diamonds from the Sytykanskaya pipe, Yakutia.European Journal of Mineralogy, Vol. 27, 1, pp. 51-56.Russia, YakutiaDeposit - Sytykanskaya
DS201503-0170
2015
Rakhmanova, M.I.Rakhmanova, M.I., Nadolinny, V.A., Yuryeva, O.P., Pokhilenko, N.P., Logvinova, A.M.Pecularities of nitrogen impurity aggregation in diamonds from the Sytykanskaya pipe, Yakutia.European Journal of Mineralogy, Vol. 27, pp. 51-56.Russia, YakutiaDeposit - Sytykanskaya
DS201509-0440
2015
Rakhmanova, M.I.Yuryeva, O.P., Rakhmanova, M.I., Nadolinny, V.A., Zedgenizov, D.A., Shatsky, V.S., Kagi, H., Komarovskikh, A.Yu.The characteristic photoluminescence and EPR features of superdeep diamonds ( Sao Luis, Brazil).Physics and Chemistry of Minerals, In press available 16p.South America, Brazil, Mato GrossoDeposit - Juina area

Abstract: Photoluminescence (PL) spectroscopy and electron paramagnetic resonance (EPR) were used for the first time to characterize properties of superdeep diamonds from the São-Luis alluvial deposits (Brazil). The infrared measurements showed the low nitrogen content (>50 of 87 diamonds from this locality were nitrogen free and belonged to type IIa) and simultaneously the extremely high level of nitrogen aggregation (pure type IaB being predominant), which indicates that diamonds under study might have formed under high pressure and temperature conditions. In most cases, PL features excited at various wavelengths (313, 473, and 532 nm) were indicative of different growth and post-growth processes during which PL centers could be formed via interaction between vacancies and nitrogen atoms. The overall presence of the 490.7 nm, H3, and H4 centers in the luminescence spectra attests to strong plastic deformations in these diamonds. The neutral vacancy known as the GR1 center has probably occurred in a number of crystals due to radiation damage in the post-growth period. The 558.5 nm PL center is found to be one of the most common defects in type IIa samples which is accompanied by the EPR center with g-factor of 2.00285. The 536 and 576 nm vibronic systems totally dominated the PL spectra of superdeep diamonds, while none of "normal" diamonds from the Mir pipe (Yakutia) with similar nitrogen characteristics showed the latter three PL centers.
DS201511-1892
2015
Rakhmanova, M.I.Yuryeva, O.P., Rakhmanova, M.I., Nadolinny, V.A., Zedgenizov, D.A., Shatsky, V.S., Kagi, H., Komarovskikh, A.Yu.The characteristic photoluminescence and EPR features of superdeep diamonds ( Sao-Luis, Brazil).Physics and chemistry of Minerals, Vol. 42, 9, pp. 707-722.South America, BrazilSao-Luis alluvials

Abstract: Photoluminescence (PL) spectroscopy and electron paramagnetic resonance (EPR) were used for the first time to characterize properties of superdeep diamonds from the São-Luis alluvial deposits (Brazil). The infrared measurements showed the low nitrogen content (>50 of 87 diamonds from this locality were nitrogen free and belonged to type IIa) and simultaneously the extremely high level of nitrogen aggregation (pure type IaB being predominant), which indicates that diamonds under study might have formed under high pressure and temperature conditions. In most cases, PL features excited at various wavelengths (313, 473, and 532 nm) were indicative of different growth and post-growth processes during which PL centers could be formed via interaction between vacancies and nitrogen atoms. The overall presence of the 490.7 nm, H3, and H4 centers in the luminescence spectra attests to strong plastic deformations in these diamonds. The neutral vacancy known as the GR1 center has probably occurred in a number of crystals due to radiation damage in the post-growth period. The 558.5 nm PL center is found to be one of the most common defects in type IIa samples which is accompanied by the EPR center with g-factor of 2.00285. The 536 and 576 nm vibronic systems totally dominated the PL spectra of superdeep diamonds, while none of "normal" diamonds from the Mir pipe (Yakutia) with similar nitrogen characteristics showed the latter three PL centers.
DS201603-0434
2015
Rakhmanova, M.I.Yureva, O.P., Rakhmanova, M.I., Nadolinny, V.A., Zedgenizov, D.A., Shatsjy, V.S., Kagi, H., Komarovskikh, A.Y.The characteristic photoluminesence and EPR features of super deep diamonds ( Sao-Luis, Brazil).Physics and Chemistry of Minerals, Vol. 42, 9, pp. 707-722.South America, BrazilDeposit - Sao-Luis

Abstract: Photoluminescence (PL) spectroscopy and electron paramagnetic resonance (EPR) were used for the first time to characterize properties of superdeep diamonds from the São-Luis alluvial deposits (Brazil). The infrared measurements showed the low nitrogen content (>50 of 87 diamonds from this locality were nitrogen free and belonged to type IIa) and simultaneously the extremely high level of nitrogen aggregation (pure type IaB being predominant), which indicates that diamonds under study might have formed under high pressure and temperature conditions. In most cases, PL features excited at various wavelengths (313, 473, and 532 nm) were indicative of different growth and post-growth processes during which PL centers could be formed via interaction between vacancies and nitrogen atoms. The overall presence of the 490.7 nm, H3, and H4 centers in the luminescence spectra attests to strong plastic deformations in these diamonds. The neutral vacancy known as the GR1 center has probably occurred in a number of crystals due to radiation damage in the post-growth period. The 558.5 nm PL center is found to be one of the most common defects in type IIa samples which is accompanied by the EPR center with g-factor of 2.00285. The 536 and 576 nm vibronic systems totally dominated the PL spectra of superdeep diamonds, while none of “normal” diamonds from the Mir pipe (Yakutia) with similar nitrogen characteristics showed the latter three PL centers.
DS201612-2351
2016
Rakhmanova, M.I.Zedgenizov, D.A., Kalinina, V.V., Reutsky, V.N., Yuryeva, O.P., Rakhmanova, M.I.Regular cuboid diamonds from placers on the northeastern Siberian platform.Lithos, Vol. 265, pp. 125-137.Russia, SiberiaDiamond morphology

Abstract: Alluvial placers of the northeastern Siberian Platform are characterized by a specific diamond population: regular cuboids, forming a continuous color series from yellowish-green to yellow and dark orange. This is the first comprehensive study of a large number of cuboid diamonds focusing on their morphology, N content and aggregation state, photoluminescence, C isotopic composition and inclusions. The cuboids are cubic (i.e. nearly flat faced) to subrounded crystals; most of them are resorbed. The cathodolominescence images and the birefringence patterns show that many cuboid diamonds record deformation. The cuboid diamonds are characterized by unusual FTIR spectra with the presence of C- (single nitrogen atom) and A- (pair of neighbour nitrogen atoms) centers, and two centers of unknown origin, termed X and Y. The presence of single substitutional nitrogen defects (C centers) in all cuboid diamonds testifies either storage in the mantle at relatively cool conditions or formation just prior to eruption of their host kimberlites. The studied diamonds are also characterized by the presence of specific set of luminescence centers: N3, H3, S1, NVo and NV?, some of which are suggested to have formed during deformation subsequent to diamond growth. The cuboid diamonds show a wide range of carbon isotope compositions from mantle-like values towards strongly 13C depleted compositions (? 6.1 to ? 20.2‰ ?13C). Combined with the finding of an eclogitic sulfide inclusion, the light carbon isotope compositions link the formation of the studied cuboids to deeply subducted basic protoliths, i.e. former oceanic crust.
DS201706-1111
2017
Rakhmanova, M.I.Yuryeva, O.P., Rakhmanova, M.I., Zedgenizov, D.A.Nature of type 1aB diamonds from the Mir kimberlite pipe (Yakutia): evidence from spectroscopic observation.Physics and Chemistry of Minerals, in press available 13p.Russia, Yakutiadeposit - Mir
DS201711-2536
2017
Rakhmanova, M.I.Yuryeva, O.P., Rakhmanova, M.I., Zedgenizov, D.A.Nature of type IaB diamonds from the Mir kimberlite pipe ( Yakutia): evidence from spectroscopic observation.Physics and Chemistry of Minerals, Vol. 44, 9, pp. 655-667.Russia, Yakutiadeposit - Mir

Abstract: In this study, the specific features of structural defects of type IaB diamonds from the Mir kimberlite pipe (Yakutian diamondiferous province) have been characterized using FTIR and photoluminescence spectroscopy. Mineral inclusions in these diamonds [olivine (Ol), orthopyroxene (OPx), chromite (Chr), sulphide (Sf)] correspond to associations of peridotite rocks at the base of the lithosphere. Nitrogen content in type IaB diamonds shows significant variations, suggesting different growth media and/or several growth stages. A specific feature of these diamonds is the absence or very small amount of platelets, which may be related to annealing during their long-term residence at the temperatures of the base of the lithosphere. All studied diamonds show the presence of hydrogen defects that are active in IR spectra with an intense line at 3107 cm?1, and additional weaker lines at 3085 and 3237 cm?1, which correlated with high nitrogen content. Type IaB diamonds are also characterized by the presence of nitrogen-nickel luminescence centres S2, S3 and 523.2 nm. This feature distinguishes them from superdeep diamonds with extreme nitrogen aggregation states, which clearly attest to different growth conditions and crystallization media of type IaB diamonds from the Mir kimberlite pipe.
DS202002-0211
2020
Rakhmanova, M.I.Nadolly, V.A., Shatsky, V.S., Yuryeva, O.P., Rakhmanova, M.I., Komarovskikh, A.Yu., Kalinin, A.A., Palyanov, Yu.N.Formation features of N3V centers in diamonds from the Kholomolokh placer in the Northeast Siberian craton.Physics and Chemistry of Minerals, Vol. 47, 4, 7p. PdfRussia, Siberiadeposit - Khololmolokh

Abstract: In recent years, despite significant progress in the development of new methods for the synthesis of diamond crystals and in their post-growth treatment, many questions remain unclear about the conditions for the formation and degradation of aggregate impurity nitrogen forms. Meanwhile, they are very important for understanding (evaluating) the origin, age, and post-growth conditions of natural diamonds. In the present work, an attempt was made to analyze the causes of the formation of high concentrations of N3V centers in natural IaB-type diamonds from the Kholomolokh placer (the Northeast Siberian craton). The possibility of decay of B centers during the plastic deformation of diamonds is analyzed and experiments on the high-temperature annealing of diamonds containing B centers are reported. The formation of N3V centers during the destruction of the B centers at high-pressure annealing of crystals has been established by experiment. It is assumed that, in the post-growth period, diamond crystals were exposed to tectono-thermal stages of raising the superplumes of the Earth's crust of the Siberian craton.
DS202005-0774
2020
Rakhmanova, M.I.Yuryeva, O.P., Rakhmanova, M.I., Zedgenizov, D.A., Kalinina, V.V.Spectroscopic evidence of the origin of brown and pink diamonds family from Internatsionalnaya kimberlite pipe ( Siberian craton).Physics and Chemistry of Minerals, Vol. 47, 20 doi.org/10/1007/ s00269-020-01088-5 19p. PdfRussiadeposit - International

Abstract: New spectroscopic data were obtained to distinguish the specific features of brown and pink diamonds from Internatsionalnaya kimberlite pipe (Siberian craton). It is shown that pink and brown samples differ markedly in the content and degree of aggregation of nitrogen defects. Pink diamonds generally have higher nitrogen content and a lower aggregation state compared to brown samples, which often show significant variations in nitrogen content and aggregation state between different growth zones. The 491 and 576 nm luminescent centres, which are signs of deformed brown diamonds, are absent or of low intensity in pink diamonds implying that high nitrogen content predominantly in A form in the pink diamonds had stiffened the diamonds against natural plastic deformation. The GR1 centre, formed by a neutrally charged vacancy, was observed only in pink diamonds, which may be due to their formation and storage in the mantle at lower-temperature conditions. Mineral inclusions indicate peridotitic and eclogitic paragenesis for studied brown and pink diamonds, respectively. It is suggested that brown diamonds have been formed in a primitive mantle at higher temperatures and/or stored there much longer.
DS202111-1778
2021
Rakhmanova, M.I.Nadolinny, V.A., Komarovskikh, A.Yu., Rakhmanova, M.I.,Yuryeva, O.P., Shatsky, V.S., Palyanov, Yu.N. Guskova, M.I.New data on the N1 nitrogen paramagnetic center in brownish type IaAB diamonds from Mir pipe.Diamond and Related Materials, Vol. 120, 108638 6p. PdfRussiadeposit - Mir

Abstract: In this work, two brownish crystals from the Mir pipe attributed to type IaAB have been examined by a complex of spectroscopic methods: electron paramagnetic resonance, infrared, and photoluminescence spectroscopies. A combination of features such as brownish color, optical system 490.7 nm, and paramagnetic centers W7 and 490.7 points out to plastic deformation of the crystals. The W7 is known to be formed as a result of destruction of A-aggregates during plastic deformation while part of the N3V centrers can be formed due to the disruption of the B-aggregates. The narrow-line EPR spectra from the nitrogen-related N3V centers and the P1 centers indicate that the crystals were annealed after plastic deformation. Another feature of the crystals studied is the observation of the well-known paramagnetic N1 center with only two magnetically inequivalent positions (i.e. with two magnetically inequivalent directions of the C1-N1 fragments) instead of the previously reported four. Possible transformation pathways of the W7 center (N1-C1-C2-N2+) into the N1 center (N1-C-N2+) during the post-deformation annealing are considered.
DS202205-0713
2022
Rakhmanova, M.I.Rakhmanova, M.I., Komarovskikh, A.Y., Ragozin, A.L., Yuryeva, O.P., Nadolinny, V.A.Sprectroscopic features of electron-irradiated diamond crystals from the Mir kimberlite pipe, Yakutia.Diamond and Related Materials, Vol. 126, 109057Russiadeposit - Mir

Abstract: The behavior of characteristic centers in diamond crystals from the Mir pipe (Yakutia) was investigated upon electron irradiation. A series of diamond crystals of different types was chosen for experiments based on the nitrogen content and aggregation parameters. In electron-irradiated diamonds of the IaAB type, a new characteristic photoluminescence system was found with a zero-phonon line (ZPL) at 615 nm together with phonon replicas of 41 and 90 meV. The phonons' energies pointed to multiphonon interactions with a quasilocal vibration of a vacancy. According to our data, the nitrogen-related defect responsible for this phenomenon contains a vacancy and may be accompanied by some other impurity. Conversely, in an almost nitrogen-free crystal, a specific system with the ZPL at 558 nm was noted. The center in question is known to be vacancy-related and was formed in type IIa crystals from the Mir pipe not only by electron irradiation but also by high-pressure high-temperature annealing when vacancies were released as a result of motion or annihilation of dislocations. Regardless of the nitrogen impurity, specific systems with the ZPL at 454, 491, and 492 nm were registered in the irradiated diamond crystals from the Mir pipe. To examine the generated defects, the irradiated diamond crystals were subjected to low-temperature annealing at ?600 °C. Although the 454 and 491 nm systems persisted, the annealing of the 492 nm system along with well-known 523.6, 489.0, and 503.4 nm (3H) centers indicated the interstitial-vacancy nature of the defect.
DS1987-0601
1987
Rakhmedov, U.Rakhmedov, U.Calcite from carbonatite rocks.(Russian)Zap. Uzbekistan. Otdel. Vses. Mineral. Obshch., (Russian), Vol. 40, pp. 75-78RussiaCrystallography, Calcite
DS200412-1614
2004
Rakin, V.I.Rakin, V.I.The shape of nonplane-faced diamonds.Doklady Earth Sciences, Vol. 395, 2, pp. 242-245.TechnologyDiamond morphology
DS200412-1818
2004
Rakin, V.I.Silaev, V.I., Chaikovskii, I.I., Rakin, V.I., Filippov, Y.N.A new type of synthetic xenomineral inclusions in diamond.Doklady Earth Sciences, Vol. 394, 1, Jan-Feb. pp. 53-57.RussiaDiamond inclusions
DS201112-0840
2010
Rakin, V.I.Rakin, V.I., Petrovsky, V.A., Sukharev, A.E., Martins, M.Morphological crystallography of Brazilian diamonds.Vestnik Komi FAN, **in Russian copy available, No. 10, pp. 2-7.South America, BrazilDiamond morphology
DS201212-0577
2012
Rakin, V.I.Rakin, V.I.Mechanical abrasion surfaces on diamond crystals.Doklady Earth Sciences, Vol. 442, 1, pp. 105-108.RussiaDiamond morphology
DS201605-0883
2015
Rakin, V.I.Petrovsky, V.A., Silaev, V.I., Sukharev, A.E., Golubeva, I.I., Rakin, V.I., Lutoev, V.P., Vasiliev, E.A.Placer forming Diamondiferous rocks and diamonds of Eastern Brazil. IN RUSS Eng. Abs.Thesis, Vestnik Permskogo Universitecta IN RUSS, Vol. 1, 30, pp. 33-59.South America, BrazilAlluvials
DS201702-0235
2016
Rakin, V.I.Rakin, V.I., Kovalchuk, O.Y., Pomazansky, B.S.Dissymmetrization of artificial and natural diamonds,Doklady Earth Sciences, Vol. 471, 2, pp. 1303-1306.TechnologyDiamond crystallography

Abstract: The occurrence rates of combinatorial types of simple polyhedra {111} are analyzed for natural and artificial diamonds. The empirical occurrence rates of 14 possible polyhedra in an isotropic environment are obtained based on numeral simulation of growth forms of octahedral crystals by the Monte-Carlo method. The phenomenon of dissymmetrization by Curie’s principle related to the crystallization conditions is established for artificial and natural diamonds.
DS1985-0600
1985
Rakmani, A.V.Serebrya, N.R., Losev, V.G., Voronov, O.A., Rakmani, A.V., Yakol.The Morphology of Diamond Crystals Synthesized from Hydrocarbons. a Technical Note.Kristallogr., Vol. 30, No. 5, PP. 1026-1027.RussiaDiamond Morphology, Synthetics
DS202012-2224
2020
Rakmanova, M.Komarovskikh, A., Rakmanova, M., Yuryeva, O., Nadolinny, V.Infrared, photoluminescence, and electron paramagnetic resonance characteristic features of diamonds from the Aikhal pipe ( Yakutia).Diamond and Related Materials, Vol. 109, 108045, 9p. PdfRussiadeposit - Aikhal

Abstract: The diversity of the defects in the collection (50 samples) of diamonds from the Aikhal pipe (Yakutia) has been studied with IR, PL, and EPR spectroscopy. The specific features of crystals have been established; the obtained information leads to the discussion about the diamond formation and growth conditions. One of the specific features observed is a high concentration of platelets. According to the platelet behavior, most of the crystals are regular suggesting the growth temperature to be 1100-1200 °C. The concentrations of A and B defects have been evaluated and the same temperature conditions have been obtained according to the Taylor diagram. Using the EPR spectroscopy, the C and N3V centers have been found in many crystals suggesting the aggregation of nitrogen during residence in the mantle at high temperatures. An interesting feature has been observed in the PL spectra. For most crystals, the spectrum with ZPL at 563.5 nm is very intensive. The structure of the observed defect is remaining unknown, the spectrum disappears as a result of annealing at 600 °C indicating the interstitial-vacancy annihilation mechanism.
DS1997-0137
1997
Rakoczy, H.Bruns, P., Rakoczy, H., Dullo, W. Ch.Slow sedimentation and Ir anomalies at the Cretaceous/ Tertiary boundaryGeologische Rundschau, Vol. 86, No. 1, pp. 168-177GlobalBoundary, Iridium anomalies
DS202103-0413
2021
Rakotomalala, A.G.Stoudmann, N., Reibelt, L.M., Rakotomalala, A.G., Randriamanjakahasina, O., Garcia, C.A., Waeber, P.O.A double edged sword: realities of artisanal and small scale mining for rural people in the Alaotra region of Madagascar. ** not specific to diamondsNatural Resources Forum, Vol 45 pp. 87-102. pdfAfrica, Madagascaralluvials

Abstract: A growing number of people are entering the artisanal and small?scale mining (ASM) sector worldwide. In Madagascar, millions of individuals depend on this informal activity. Through a case study in the Alaotra?Mangoro region of Madagascar, our research aimed to understand the "bottom?up" dynamics and ripple effects of the sector, by looking at the realities for rural communities where inhabitants are both directly and indirectly affected by ASM. We were interested in community members' and miners' perceptions of the socio?economic and environmental impacts of ASM, and in identifying the factors attracting people living in one of the country's agricultural hubs to this activity. Our results show a wide diversity of push and pull factors leading people to enter the sector. Although many positive impacts of ASM exist for miners and communities within the vicinity of mines, most miner participants considered themselves worse off since starting to mine, highlighting the high risk and low probability of return of ASM. ASM's potential for local and national development will remain squandered if its negative impacts continue to go unmanaged. Accounting for local contexts and the ripple effects of ASM will be crucial in achieving safety and security for miners, and to tap into the benefits it may offer communities while minimising environmental damage.
DS201801-0050
2017
Rakotondraibe, T.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.
DS201709-1984
2017
Rakotondrazafy, A.F.M.Feneyrol, J., Giuliani, G., Demaiffe, D., Ohenstetter, D., Fallick, A.E., Dubessy, J., Martelet, J-E., Rakotondrazafy, A.F.M., Omito, E., Ichangi, D., Nyamai, C., Wamunyu, W.Age and origin of the tsavorite and tanzanite mineralozing fluids in the Neoproterozoic Mozambique metamorphic belt.The Canadian Mineralogist, Vol. 55, pp. 763-786.Africa, Kenya, Tanzania, Madagascartanzanite

Abstract: The genetic model previously proposed for tsavorite- (and tanzanite-) bearing mineralization hosted in the Neoproterozoic Metamorphic Mozambique Belt (stretching from Kenya through Tanzania to Madagascar) is refined on the basis of new Sm-Nd age determinations and detailed Sr-O-S isotope and fluid-inclusion studies. The deposits are hosted within meta-sedimentary series composed of quartzites, graphitic gneisses, calc-silicate rocks intercalated with meta-evaporites, and marbles. Tsavorite occurs either in nodules (also called “boudins”) oriented parallel to the metamorphic foliation in all of the deposits in the metamorphic belt or in quartz veins and lenses located at the hinges of anticlinal folds (Lelatema fold belt and Ruangwa deposits, Tanzania). Gem tanzanite occurs in pockets and lenses in the Lelatema fold belt of northern Tanzania. The Sm-Nd isotopic data for tsavorites and tanzanites hosted in quartz veins and lenses from Merelani demonstrate that they formed at 600 Ma, during the retrograde metamorphic episode associated with the East African Orogeny. The tsavorites hosted in nodules do not provide reliable ages: their sedimentary protoliths had heterogeneous compositions and their Sm-Nd system was not completely rehomogenized, even at the local scale, by the fluid-absent metamorphic recrystallization. The initial 87Sr/86Sr isotopic ratios of calcite from marble and tanzanites from Merelani fit with the strontium isotopic composition of Neoproterozoic marine carbonates. Seawater sediment deposition in the Mozambique Ocean took place around 720 Ma. The quartz-zoisite O-isotopic thermometer indicates a temperature of formation for zoisite between 385 and 448 °C. The sulfur isotopic composition of pyrite (between –7.8 and –1.3‰ V-CDT) associated with tsavorite in the Lelatema fold belt deposits suggests the contribution of reduced marine sulfate. The sulfur in pyrite in the marbles was likely derived from bacterial sulfate reduction which produced H2S. Fluid inclusion data from tsavorite and tanzanite samples from the Merelani mine indicate the presence of a dominant H2S-S8±(CH4)±(N2)±(H2O)-bearing fluid. In the deposits in Kenya and Madagascar, the replacement of sulfate by tsavorite in the nodules and the boron isotopic composition of tourmaline associated with tsavorite are strong arguments in favor of the participation of evaporites in garnet formation.
DS2000-0621
2000
Rakotondrazafy, R.Martelat, J.E., Lardeaux, J.M., Rakotondrazafy, R.Strain pattern and late Precambrian deformation history in southern MadagascarPrecambrian Research, Vol. 102, No. 1-2, July 1, pp. 1-20.MadagascarTectonics
DS1998-1477
1998
RakotosolofoTorsvik, T., Tucker, Ashwal, Eide, Rakotosolofo, De WitMadagascar: Cretaceous volcanism and the Marian hot spotJournal of African Earth Sciences, Vol. 27, 1A, p. 197. AbstractMadagascarvolcanism., Plume
DS1998-1204
1998
Rakotosolofo, N.A.Rakotosolofo, N.A., Torsvik, Ashwal, De Wit, EideMadagascar during the Late Paleozoic and MesozoicJournal of African Earth Sciences, Vol. 27, 1A, p. 148. AbstractMadagascarTectonics
DS2003-0937
2003
Rakovan, J.Meng, Y., Newville, M., Sutton, S., Rakovan, J., Mao, H-K.Fe and Ni impurities in synthetic diamondAmerican Mineralogist, Vol. 88, 10, Oct. pp. 1555-69.GlobalDiamond - synthesis
DS200412-1297
2003
Rakovan, J.Meng, Y., Newville, M., Sutton, S., Rakovan, J., Mao, H-K.Fe and Ni impurities in synthetic diamond.American Mineralogist, Vol. 88, 10, Oct. pp. 1555-69.TechnologyDiamond - synthesis
DS200812-0932
2008
Rakovan, J.Rakovan, J.Kimberlite - one of the best preserved dikes - and possible the first found - is currently located in a parking lot on Green Street in downtown Syracuse, N.Y.Rocks and Minerals, Vol. 83, May-June, p. 83-84.United States, New YorkHistory
DS202205-0674
2022
Ralchenko, V.G.Boldyrev, K.N., Sedov, V.S., Vanpoucke, D.E.P., Ralchenko, V.G., Mavrin, B.N.Photoluminescence and first principles phonon study.Diamond and Related Materials, Vol. 126, 6p. PdfGlobalLuminescence
DS1994-0134
1994
Raleigh, C.B.Behr, H.J., Raleigh, C.B.Crustal structure of the Bohemian Massif and the West CarpathiansSpringer, 372pEuropeBook -ad, Variscan Belt
DS1997-0943
1997
Ralfe, G.Ralfe, G.De Beers and the diamond industry: towards the new millenniumPreprint from De Beers, CSO, 5p. 5 slide viewsGlobalEconomics, CSO
DS2001-0961
2001
Ralfe, G.Ralfe, G.De Beers in the 21 st CenturyProspectors and Developers Association of Canada (PDAC) Luncheon address, March 12, Offprint of speech approx. 15p.GlobalNews item, De Beers
DS2001-0962
2001
Ralfe, G.Ralfe, G.De Beers in the 21st CenturyProspectors and Developers Association of Canada (PDAC) Luncheon address, March 12, Offprint of speech approx. 15p.GlobalNews item, De Beers
DS1991-1296
1991
Ralser, S.Park, A.F., Ralser, S.Structure of the early Proterozoic Hurwitz Group in the Tavani area, Keewatin, Northwest TerritoriesCanadian Journal of Earth Sciences, Vol. 28, No. 7, July pp. 1078-1095Northwest TerritoriesStructure, Proterozoic
DS1989-1250
1989
Ram Babu, H.V.Ram Babu, H.V., Atchuta Rao, D., et al.MAGTRAN: a computer program for the transformation of magnetic and gravityanomaliesComputers and Geosciences, Vol. 15, No. 6, pp. 979-988GlobalComputer, Program -MAGTRAN.
DS201508-0358
2015
Ram Moham, M.He, 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
DS200412-1219
2004
Ram Mohan, M.Maniyamba, C., Kerrich, R., Naqvi, S.M., Ram Mohan, M.Geochemical systematics of tholeitic basalts from the 2.7 Ga Ramagiri Hungund composite greemstone belt, Dharwar Craton.Precambrian Research, Vol. 134, no. 1-2, Sept. 20, pp. 21-39.IndiaGeochronology - not specific to diamonds
DS200512-0681
2005
Ram Mohan, M.Manikyamba, C., Naqvi, S.M., Subba Rao, D.V., Ram Mohan, M., Khanna, T.C., Rao, T.G., Reddy, G.L.Boninites from the Neoarchean Gadwal greenstone belt, eastern Dharwar Craton, India, implications for Archean subduction processes.Earth and Planetary Science Letters, Vol. 230, 1-2, pp. 65-83.IndiaBoninites
DS201212-0578
2012
Ram Mohan, M.Ram Mohan, M., Singh, S.P., Santosh, M., Siddiqui, M.A., Balaram, V.TTG suite from the Bundelk hand Craton, Central India: geochemistry, petrogenesis and implications for Archean crustal evolution.Journal of Asian Earth Sciences, Vol. 58, pp. 38-50.IndiaTectonics
DS200512-1149
2003
Ram Mohan, V.Vladykin, N.V., Viladkar, S.G., Miyazaki, T., Ram Mohan, V.Chemical composition of carbonatites of Tamil Nadu massif ( South India) and problem of benstoonite carbonatites.Plumes and problems of deep sources of alkaline magmatism, pp. 130-154.IndiaCarbonatite, geochemistry
DS1998-1422
1998
Rama Brahman, G.Sundararajan, N., Rama Brahman, G.Spectral analysis of gravity anomalies caused by slab like structures: a Hartley Transform technique.Journal of Applied Geophys., Vol. 39, No. 1, May 10, pp. 53-65.MantleGeophysics - gravity, Slab - not specific to diamonds
DS1988-0581
1988
Rama Murthy, V.Roden, M.F., Irving, A.J., Rama Murthy, V.Isotopic and trace element composition of the upper mantle beneath a young continental rift: results from Kilbourne Hole,New MexicoGeochimica et Cosmochimica Acta, Vol. 52, No. 2, February pp. 461-474New MexicoBlank
DS1992-1250
1992
Rama Murthy, V.Rama Murthy, V., et al.Siderophile elements and the earth's formationScience, Vol. 257, August 28, pp. 1281-1285GlobalMantle, Siderophile elements -discussion
DS201112-0841
2011
Rama Rao, Ch.Rama Rao, Ch., Kishore, R.K., Kumar, R.P., Babu, B.B.Delineation of intra crustal horizon in Eastern Dharwar Craton - an aeromagntic evidence.Journal of Asian Earth Sciences, Vol. 40, 2, Jan. pp. 534-541.IndiaGeophysics - magnetics
DS200612-1226
2005
Rama Rao, G.Sastry, C.A., Rama Rao, G., Prasad, G.J.S., Reddy, V.A.Electro probe micro analysis of indicator minerals from kimberlites of Andhra Pradesh and Karnataka.Geological Survey of India, Bulletin, C6, 282p. Cited in GJSI. 67, 2, p. 280.India, Andhra Pradesh, KarnatakaGeochemistry
DS200812-0858
2008
Rama Rao, G.Patel, S.C., Ravi, S., Rao, C.R.M., Rama Rao, G., Nayak, S.S.Mineralogy and geochemistry of Wajrakaruru kimberlites, southen India.9IKC.com, 3p. extended abstractIndiaDeposit - Wajrakarur petrography
DS202010-1870
2020
Rama Rao, J.V.Rama Rao, J.V., Kumar, B.R., Kumar, M., Singh, R.B., Veeraich, B.Gravity of Dharwar craton, southern Indian shield.Journal of Geological Society of India, Vol. 96, 3, pp. 239-249. pdfIndiacraton

Abstract: Dharwar craton (DC), by far the largest geological domain in South Indian Shield, occupying about 0.5 million sq. km area, is well-studied terrain both for regional geoscientific aspects and as part of mineral exploration over several important blocks such as the greenstone belts, ultramafic complexes, granite-gneissic terrain and the Proterozoic sediments of Cuddapah basin. The re-look into regional gravity data offers several insights into nature of crust, sub-divisions within the craton, bedrock geology in the covered areas and mineral potentiality of this ancient and stable crust. The regional gravity profiles drawn across the south Indian region mainly suggest that the area can be divided into five domains as Western Dharwar craton (WDC), Central Dharwar craton (CDC), Eastern Dharwar craton (EDC 1), transitory zone of EDC (EDC 2) and Eastern Ghats mobile belt (EGMB) areas. The Bouguer gravity anomaly pattern also questions some of the earlier divisions like eastern margin of Chitradurga schist belt between the WDC and EDC and the boundary of DC with southern granulite terrain (SGT) as they do not restrict at these main boundaries. In this study, mainly four issues are addressed by qualitative and quantitative analysis of regional gravity data and those revealed significant inferences. (1) A distinct gravity character in central part of south Indian shield area occupying about 60, 000 sq. km, suggests that the transitory crustal block, faulted on both sides and uplifted. This area designated as central Dharwar craton (CDC) is characterized with schist belts having characters of both parts of western and eastern Dharwar craton. This inference also opens up the debate about the boundary between western and eastern parts of the craton. Another significant inference is the extension of major schist belts beneath both Deccan volcanic province (DVP) in northwestern part and Cuddapah basin (CB) in southeastern part. (2) Eastern Dharwar craton is reflected as two distinct domains of different gravity characters; one populated with number of circular gravity lows and a few linear gravity high closures indicative of plutonic and volcanic activity and another domain devoid of these intrusive younger granites or schist belts. (3) Large wave length gravity highs occupying thousands of sq.km area and those not relatable to surface geology in eastern Dharwar craton that may have significance for mineral exploration. (4) Gravity data was subjected to further processing like two dimensional modeling which have yielded insights into crustal architecture beneath the Dharwar craton, crustal scale lineaments, craton-mobile belt contact zone and younger intrusives.
DS200612-0875
2001
Ramachandra, H.M.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
DS200612-1123
2005
Ramachandra, H.M.Ramachandra, H.M.Crustal evolution in Bastar Craton preceding kimberlite and related magmatism.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 87-93.India, Bastar CratonTectonics
DS2003-0543
2003
Ramachandran, K.Hammer, P.T.C., Clowes, R.M., Ramachandran, K.Seismic reflection techniques for imaging Diamondiferous kimberlite dykes: a case studyGeological Association of Canada Annual Meeting, Abstract onlyNorthwest TerritoriesGeophysics - seismics
DS2003-0544
2003
Ramachandran, K.Hammer, P.T.C., Ramachandran, K., Clowes, R.M.Seismic imaging of thin, Diamondiferous kimberlite dykes8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, AbstractGlobalDiamond exploration - geophysics, seismics
DS200412-0774
2003
Ramachandran, K.Hammer, P.T.C., Clowes, R.M., Ramachandran, K.Seismic reflection techniques for imaging Diamondiferous kimberlite dykes: a case study from Snap Lake, N.W.T.Geological Association of Canada Annual Meeting, Abstract onlyCanada, Northwest TerritoriesGeophysics - seismics
DS200412-0775
2003
Ramachandran, K.Hammer, P.T.C., Ramachandran, K., Clowes, R.M.Seismic imaging of thin, Diamondiferous kimberlite dykes.8 IKC Program, Session 8, AbstractTechnologyDiamond exploration - geophysics, seismics
DS200512-0395
2004
Ramachandran, K.Hammer, P.T.C., Clowes, R.M., Ramachandran, K.High resolution seismic reflection imaging of a thin, Diamondiferous dyke.Geophysics, Vol. 69, 5, pp. 1143-1154.Canada, Northwest TerritoriesGeophysics - seismics, Snap Lake
DS201511-1877
2015
Ramachandran, K.T.Sastry, M.D., Mane, S., Gaonkar, M., Bhide, M.K., Desai, S.N., Ramachandran, K.T.Luminescence studies of gemstones and diamonds.International Journal of Luminescence and Applications, Vol. 5, 3, pp. 293-297.TechnologyLuminescence

Abstract: Some of the minerals like Corundum, chryso beryl, beryllium alumino silicate (emerald) and also Diamond exhibit exceptional optical properties[1] and in some cases attractive colours; in India these were recognized quite early since the days of Indus valley civilization. In more recent times there has been a lot of scientific interest in colours and colour modifications in Gem minerals and in Diamonds. Science of gem stones deals with their identification by non destructive means and understanding of origin of colour and excellent optical properties[1]. Optical methods have long been used to obtain properties like ‘Refractive Index’ which still remains an important parameter as a preliminary test to identify the gemstone/mineral. The spectroscopic studies of gem grade minerals are essentially directed towards some of these features in identifying and understanding the spectral properties of chromophores, either chemical impurities and/or radiation induced point defects, in solids. In this context a variety of spectroscopic methods are used to address the problems of the Gem stone identification and identification of origin of colours and colour modification treatments. The methods frequently used in Gem testing labs are the following: (i)Electronic absorption in UV-Visible-NIR range.(ii)UV-Vis excited luminescence, (iii) Vibrational spectra – Absorption in the Infra red range (iv) Vibrational spectra using Light Scattering (Raman spectroscopy) (v)Surface Fluorescence mapping Under deep UV excitation. The present paper deals with the luminescence studies in rubies, sapphires, emeralds and diamonds. Special mention may be made of fluorescence mapping using deep UV excitation (around 205 nm) corresponding to the band gap of diamond. Under such an excitation inter band excitation takes place creating a e-h pair and most of the absorption and subsequent emission being restricted to the surface. This makes surface mapping possible and thereby elucidating the growth patterns. This is invaluable in the diagnostics for the detection of synthetic diamonds. In this introductory presentation on the Luminescence methods in Gemmology, we give a brief account of optical spectroscopic methods which mainly deal with identification of corundum based gem stones (rubies, sapphire) and diamonds including the electronic absorption and luminescence of chromophore centres. In gem testing infrared absorption and Raman scattering methods are main work horses and they will be brought in as and when necessary to give a complete picture.
DS2002-1301
2002
Ramadass, G.Ramadass, G., Ramaprasada Rao, I.B., Himanbindu, D., Srinivasulu, N.Psuedo surface velocities ( densities) and pseudo depth densities ( velocities) along selected profiles in the Dharwar Craton, India.Current Science, Vol. 82,No. 2, Jan. 25, pp. 197-201.IndiaGeophysics - seismics
DS2002-1302
2002
Ramadass, G.Ramadass, G., Rao, I.B.R., Himabindu, D., SrinivasuluPseudo surface velocities (densities) and pseudo depth densities along profiles Dharwar Craton, India.Current Science, Vol.82,No.2, pp. 197-201.IndiaGeophysics - seismics, Craton - Dharwar
DS2003-1126
2003
Ramadass, G.Ramadass, G., Rao, I.B.R., Srinivasulu, N., Himabindu, D.Density studies in the Dharwar Craton along the Jadcharla Goa subtransectJournal Geological Society of India, Vol. 61, 4, pp. 439-448.IndiaGeophysics - seismics
DS200412-1615
2003
Ramadass, G.Ramadass, G., Rao, I.B.R., Srinivasulu, N., Himabindu, D.Density studies in the Dharwar Craton along the Jadcharla Goa subtransect.Journal Geological Society of India, Vol. 61, 4, pp. 439-448.IndiaGeophysics - seismics
DS200512-0888
2005
Ramadass, G.Ramadass, G., Rao, I.B.R., Himabindu, D.Regional appraisal from gravity investigations in the Dharwar Craton: Jadcharla - Goa transect.Journal of the Geological Society of India, Vol. 65, 1, pp. 61-69.IndiaGeophysics - gravity not specific to diamonds
DS200612-1124
2006
Ramadass, G.Ramadass, G., Ramaprasada Rao, I.B., Himnindu, D.Crustal configuration of the Dhawar Craton, India: based on joint modelling of regional gravity and magnetic data.Journal of Asian Earth Sciences, Vol. 26, 5, pp. 437-448.Asia, IndiaGeophysics - gravity, magnetics
DS200912-0792
2009
Ramadass, G.Veeraiah, B., Ramadass, G., Himabindu, D.A subsurface criterion for predictive exploration of kimberlites from bouguer gravity in the eastern Dharwar craton, India.Journal of the Geological Society of India, Vol. 74, July pp. 69-77.IndiaMaddur-Narayanpet kimberlite, geophysics
DS201112-1084
2009
Ramadass, G.Veeraiah, B., Ramadass, G., Himabindu, D.A subsurface criterion for predictive exploration of kimberlites from Bouguer Gravity in the eastern Dharwa craton, India.Journal of the Geological Society of India, Vol. 74, pp. 69-77.IndiaNarayanpet-Irladinne area
DS201612-2319
2016
Ramakokovhu, M.M.Mahlangu, T., Moemise, N., Ramakokovhu, M.M., Olubambi, P.A., Shongwe, M.B.Seperation of kimberlite from waste rocks using sensor-based sorting at Culli nan diamond mine.Journal of South African Institute of Mining and Metallurgy, Vol. 116, Apr. pp. 343-348.Africa, South AfricaDeposit - Cullinan

Abstract: Near-infrared (NIR) spectroscopy sorting technology is incorporated in an automated optical mineral sorter that can discriminate between materials using the differences in characteristics when exposed to near-infrared radiation. During September 2014 to April 2015, a pilot plant that utilized NIR technology to discriminate between kimberlite and waste materials was commissioned to determine the viability of including this technology in the diamond winning process flow sheet at Cullinan Diamond Mine. The plant was used to minimize the waste content in the size fraction -70+35 mm that reports to the crushing section and then to the dense media separation process. This paper describes the initial test work, conducted at Mintek, that led to the decision to conduct a pilot-scale study. The mineralogical characterization of the feed and product streams to establish the sorting criteria and the operational data obtained during the pilot plant campaign are described. The results indicated a good possibility of discriminating between the kimberlite and waste material using NIR technology. However, the consistency of discrimination was not good enough to avoid the risk of potential diamond loss. Furthermore, a lower than expected availability of the machine reduced the throughput capabilities.
DS201709-2028
2016
Ramakokovhu, M.M.Mahlangau, T., Moemise, N., Ramakokovhu, M.M., Olubambi, P.A., Shongwe, M.B.Separation of kimberlite from waste rocks using sensor based sorting at Culli nan diamond mine.South African Institute of Mining and Metallurgy, Vol. 116, 4, pp. 343-350.Africa, South Africadeposit - Cullinan

Abstract: Near-infrared (NIR) spectroscopy sorting technology is incorporated in an automated optical mineral sorter that can discriminate between materials using the differences in characteristics when exposed to near-infrared radiation. During September 2014 to April 2015, a pilot plant that utilized NIR technology to discriminate between kimberlite and waste materials was commissioned to determine the viability of including this technology in the diamond winning process flow sheet at Cullinan Diamond Mine. The plant was used to minimize the waste content in the size fraction -70+35 mm that reports to the crushing section and then to the dense media separation process. This paper describes the initial test work, conducted at Mintek, that led to the decision to conduct a pilot-scale study. The mineralogical characterization of the feed and product streams to establish the sorting criteria and the operational data obtained during the pilot plant campaign are described. The results indicated a good possibility of discriminating between the kimberlite and waste material using NIR technology. However, the consistency of discrimination was not good enough to avoid the risk of potential diamond loss. Furthermore, a lower than expected availability of the machine reduced the throughput capabilities.
DS200412-1616
2004
Ramakrishnan, M.Ramakrishnan, M.Advances in the Precambrian of central India.Journal of Geological Society of India, Vol. 63, 2, pp. 239-242.IndiaGeology - regional
DS200912-0611
2009
Ramakrishnan, M.Ramakrishnan, M.Precambrian mafic magmatism in the western Dharwar Craton, southern India.Journal of the Geological Society of India, Vol. 73, 1, pp. 101-116.IndiaMagmatism
DS1985-0133
1985
Ramakrishnan, S.Cullers, R.L., Ramakrishnan, S., Berendsen, P., Griffin, T.Geochemistry and Petrogenesis of Lamproites, Late Cretaceous Age, Woodson County, Kansas, United States (us)Geochimica et Cosmochimica Acta ., Vol. 49, PP. 1383-1402.United States, Central States, KansasLamproite Terminology, Analyses, Silver City Dome
DS201212-0750
2012
Ramakrishnarao, M.V.Vani, T., Haga Laksmi, V., Ramakrishnarao, M.V., Kelly, G.R., Subbarao, K.V.Integration of geophsyical and geological dat a of kimberlites in Narayayanapet - Maddur field, Andhra Pradesh, India.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractIndia, Andhra PradeshDeposit - Narayayanapet-Maddur
DS201412-0941
2013
Ramakrishnarao, M.V.Vani, T., Lakshimi, V.N., Ramakrishnarao, M.V., Keller, G.R., Subbarao, K.V.Integration of geophysical and geological dat a of kimberlites in Narayanpet-Maddur field, Andhra Pradesh, India.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 229-240.India, Andhra PradeshDeposit - Narayanpet- Maddur
DS202005-0761
2019
Ramakrsihna Reddy, N.Singh, T.D., Manikyamba, C., Subramanyam, K.S.V., Ganguly, S., Khelen, A., Ramakrsihna Reddy, N.Mantle heterogeneity, plume-lithosphere interaction at rift controlled ocean-continent transition zone: evidence from trace PGE geochemistry of Vempalle flows, Cuddapah basin India.Geoscience Frontiers, in press, 20p. PdfIndiaREE

Abstract: This study reports major, trace, rare earth and platinum group element compositions of lava flows from the Vempalle Formation of Cuddapah Basin through an integrated petrological and geochemical approach to address mantle conditions, magma generation processes and tectonic regimes involved in their formation. Six flows have been identified on the basis of morphological features and systematic three-tier arrangement of vesicular-entablature-colonnade zones. Petrographically, the studied flows are porphyritic basalts with plagioclase and clinopyroxene representing dominant phenocrystal phases. Major and trace element characteristics reflect moderate magmatic differentiation and fractional crystallization of tholeiitic magmas. Chondrite-normalized REE patterns corroborate pronounced LREE/HREE fractionation with LREE enrichment over MREE and HREE. Primitive mantle normalized trace element abundances are marked by LILE-LREE enrichment with relative HFSE depletion collectively conforming to intraplate magmatism with contributions from sub-continental lithospheric mantle (SCLM) and extensive melt-crust interaction. PGE compositions of Vempalle lavas attest to early sulphur-saturated nature of magmas with pronounced sulphide fractionation, while PPGE enrichment over IPGE and higher Pd/Ir ratios accord to the role of a metasomatized lithospheric mantle in the genesis of the lava flows. HFSE-REE-PGE systematics invoke heterogeneous mantle sources comprising depleted asthenospheric MORB type components combined with plume type melts. HFSE-REE variations account for polybaric melting at variable depths ranging from garnet to spinel lherzolite compositional domains of mantle. Intraplate tectonic setting for the Vempalle flows with P-MORB affinity is further substantiated by (i) their origin from a rising mantle plume trapping depleted asthenospheric MORB mantle during ascent, (ii) interaction between plume-derived melts and SCLM, (iii) their rift-controlled intrabasinal emplacement through Archean-Proterozoic cratonic blocks in a subduction-unrelated ocean-continent transition zone (OCTZ). The present study is significant in light of the evolution of Cuddapah basin in the global tectonic framework in terms of its association with Antarctica, plume incubation, lithospheric melting and thinning, asthenospheric infiltration collectively affecting the rifted margin of eastern Dharwar Craton and serving as precursors to supercontinent disintegration.
DS1975-0387
1976
RamalingaswanyRamalingaswanyOn the Possibility of Kimberlite Dyke in Giddalur AreaIndia Geological Survey, UNPUBL.India, Andhra PradeshBlank
DS1999-0578
1999
Ramam, P.K.Ramam, P.K.Mineral resources of Andhra Pradesh.Kimberlites - lamproites pp. 11-13.Diamonds pp. 114-32.Geological Society India, 253p.India, Andhra PradeshDiamonds - Wajrakaruru, Maddur-Kotakonda, QPC Banganapaale, Narayanpet, Mahboobnagar
DS1940-0057
1942
Raman, C.V.Raman, C.V.The Physics of the DiamondCurrent Science., Vol. 11, No. 7, PP.IndiaCrystallography, Morphology, Natural Diamond
DS1940-0127
1946
Raman, C.V.Raman, C.V., Ramashesham, S.The Crystal Forms of Diamond and their SignificanceIndian Academy of Science Proceedings, Vol. 24, No. 1, PP.IndiaCrystallography, Diamond, Morphology, Natural Diamond
DS1950-0039
1950
Raman, C.V.Raman, C.V., Jayaraman, A.The Luminescence of Diamond and its Relation to Crystal Structure.Indian Academy of Science Proceedings, Vol. 32, SECT. A, No. 2IndiaCrystallography
DS1950-0294
1956
Raman, C.V.Raman, C.V.The Diamond (1956)Indian Academy of Science Proceedings, Vol. 44, SECT. A, No. 3, PP. 99-110.IndiaCrystallography, Mineralogy
DS1950-0295
1956
Raman, C.V.Raman, C.V.The Specific Heat of Crystals. Pt. 1. Grand Theory. Pt. 2. The Case of Diamond.Indian Academy of Science Proceedings, Vol. 44, SECT. A, No. 4, PP. 153-164.IndiaCrystallography, Mineralogy
DS1950-0349
1957
Raman, C.V.Raman, C.V.The Heat Capacity of Diamond Between 0 K and 1000 KIndian Academy of Science Proceedings, Vol. 46, SECT. A, No. 5, PP. 323-332.IndiaCrystallography
DS1950-0423
1958
Raman, C.V.Raman, C.V.The Diffraction of X-rays by Diamond. Pt. 2Indian Academy of Science Proceedings, Vol. 47, SECT. A, No. 6, PP. 335-343.IndiaCrystallography, Mineralogy
DS1960-1196
1969
Raman, C.V.Raman, C.V.The Diamond (1969)Unknown, 246P.GlobalPhysics, Infrared, Luminescence, Morphology
DS1960-1010
1968
Raman, G.V.Raman, G.V.The Diamonds of the Krishna ValleyCurrent Science., Vol. 37, No. 19, PP. 541-542.India, Andhra PradeshDiamond Occurrences
DS1987-0397
1987
Ramana, Y.V.Lastovickova, M., Ramana, Y.V., Gogte, B.S.Electrical conductivity of some rocks from the Indian subcontinentStudies Geophysics Geody, Vol.31, No. 1 pp. 60-72IndiaGeophysics, Kimberlite
DS1987-0262
1987
Ramana Rao, A.V.Guptasarma, D., Chetty, T.R.K., Murthy, D.S.N., Ramana Rao, A.V.Case history of a kimberlite discovery, Wajrakarur area, Andhra IndiaExploration 87, technical abstract volume, held Toronto Sept. 2 27-Oct, p. 25. abstract onlyIndiaGeomorphology, Indicator minerals
DS1988-0277
1988
Ramana Rao, A.V.Guptasarma, D., Chetty, T.R.K., Murthy, D.S.N., Ramana Rao, A.V.Case history of a kimberlite discovery, Wajrakaur area, A.P.,SouthIndiaExploration 87, Proceedings Volume, Ontario Geological Survey, Special Publishing No. 3, pp. 888-897IndiaGeophysics
DS1988-0561
1988
Ramananantoandro, R.Ramananantoandro, R.Seismic evidence for mantle flow beneath the Massif Central rift zone, France.Canadian Journal of Earth Sciences, Vol. 25, pp. 2139-42.FranceGeophysics - seismic, Rifting
DS1994-1428
1994
Ramani, R.J.Ramani, R.J., Mozumdar, B.K., Samaddar, A.B.Computers in mineral industryA.a.balkema, 350pGlobalEconomics, evaluation, geostatistics, ore reserves, Book -table of contents
DS200512-0522
2004
Ramanko, E.F.Kharkiv, A.D., Ramanko, E.F., Zubarev, B.M.Kimberlites of Zimbabwe: abundance and composition.Russian Geology and Geophysics, Vol. 45, 3, pp. 317-327.Africa, ZimbabweOverview
DS1994-1429
1994
Ramanowiez, B.Ramanowiez, B.An elastic tomography: a new perspective on upper mantle thermal structureEarth Planetary Science Letters, Vol. 128, No. 3-4, Dec. pp. 113-122.MantleTomography
DS2002-1301
2002
Ramaprasada Rao, I.B.Ramadass, G., Ramaprasada Rao, I.B., Himanbindu, D., Srinivasulu, N.Psuedo surface velocities ( densities) and pseudo depth densities ( velocities) along selected profiles in the Dharwar Craton, India.Current Science, Vol. 82,No. 2, Jan. 25, pp. 197-201.IndiaGeophysics - seismics
DS200612-1124
2006
Ramaprasada Rao, I.B.Ramadass, G., Ramaprasada Rao, I.B., Himnindu, D.Crustal configuration of the Dhawar Craton, India: based on joint modelling of regional gravity and magnetic data.Journal of Asian Earth Sciences, Vol. 26, 5, pp. 437-448.Asia, IndiaGeophysics - gravity, magnetics
DS1991-1395
1991
Ramarao, Ch.Ramarao, Ch., Chetty, T.R.K., Lingaiah, A., Babu Rao, V.Delineation of a greenstone belt using aeromagnetics, Land sat and photogeology - a case study from the South Indian ShieldGeoexploration, Vol. 28, pp. 121-137IndiaRemote sensing, Geophysics -magnetics, linements
DS201607-1374
2016
Ramarao, J.Ramarao, J.Gravity anomalies over Indian cratons and their geological implications.IGC 35th., Session The Deep Earth 1 p. abstractIndiaGeophysics - gravity
DS1960-0291
1962
Ramarathnam, S.Ramarathnam, S.Geology and Petrology of the Southern Portion of the Laramie Anorthosite Massif, Albany County, Wyoming.Golden: Ph.d. Thesis, Colorado School Mines, 131P.United States, Wyoming, Rocky MountainsRegional Studies
DS2000-0374
2000
RamasamyGwalani, L.G., Rock, N.M.S., Ramasamy, Griffin, MulaiComplexly zoned Ti rich melanite schorlomite garnets from Ambadungar carbonatite alkalic complex, DeccanJournal of Asian Earth Science, Vol. 18, No.2, Apr. pp.163-76.India, Gujarat, WesternCarbonatite, Deposit - Ambadungar
DS2002-1209
2002
Ramasamy, A.K.Pandit, M.K., Sial, A.N., Sukumaran, G.B., Pimentel, M.M., Ramasamy, A.K.Depleted and enriched mantle sources for Paleo- and Neoproterozoic carbonatites ofChemical Geology, Vol. 189,1-2,pp. 69-89.India, Tamil NaduCarbonatite - geochronology, Deposit - Samalpatti, Sevattur, Mulakkasu
DS1980-0284
1980
Ramasamy, R.Ramasamy, R.Tectonomagmatic Evolution of Carbonatite Complex of Tiruppattur, India.Proceedings of the 26th International Geological Congress, Vol. 1, SECT. 5 P. 80. (abstract.).India, Tamil NaduCarbonatite, Related Rocks
DS1980-0285
1980
Ramasamy, R.Ramasamy, R., Shapenko, V.Fluid Inclusion Studies in Carbonatites of Tiruppattur, IndiProceedings of the 26th International Geological Congress, Vol. 1, SECT. 5 P. 79. (abstract.).India, Tamil NaduCarbonatite, Related Rocks, Isotope
DS1982-0514
1982
Ramasamy, R.Ramasamy, R.The Supposed Eastern Ghats Paleorift Zone on the Indian Subcontinent.Moscow University Bulletin., Vol. 37, No. 2, PP. 31-36.IndiaCarbonatite, Tectonics, Rifting, Related Rocks
DS1986-0661
1986
Ramasamy, R.Ramasamy, R.Calcium rich pyroxenes from the carbonatite complex of Tiruppatur, Tamil NaduCurrent Science, Vol. 55, No. 20, pp. 981-984IndiaCarbonatite
DS1992-1251
1992
Ramasamy, R.Ramasamy, R.Carbonatite-apatite from carbonatites of Kudangulam near Cape Comorin, Tamilnadu.Indian Minerals, Vol. 46, No. 1, January-March pp. 91-94.IndiaCarbonatite
DS1995-1539
1995
Ramasamy, R.Ramasamy, R.Effects of metasomatism on the country rocks around carbonatites of Kudangulam area, Tamil Nadu.Journal of Geological Society India, Vol. 46, No. 2, August pp. 117-124.IndiaCarbonatite
DS1995-1659
1995
Ramasamy, R.Saravanan, S., Ramasamy, R.Geochemistry and petrogenesis of shonkinite and associated alkaline Rocks of Tiruppattur carbonatite complex.Journal of Geological Society India, Vol. 46, No. 3, Sept. pp. 235-244.IndiaCarbonatite, Deposit -Tiruppattur
DS1997-0944
1997
Ramasamy, R.Ramasamy, R., Gwalani, L.G., Randive, K.R., Mulai, B.P.Geology of the Indian carbonatites and evolution of alkali carbonatite magma in peninsular India.Geological Association of Canada (GAC) Abstracts, POSTER.IndiaCarbonatite
DS2000-0792
2000
Ramasamy, R.Ramasamy, R., Gwalani, L.G., Pandit, M.K.Geology of Indian carbonatites and evolution of alkali carbonatite magmaIgc 30th. Brasil, Aug. abstract only 1p.IndiaTectonics - rifting, Carbonatite
DS2001-0963
2001
Ramasamy, R.Ramasamy, R., Gwalani, L.G., Subramanian, S.P.A note on the occurrence and formation of magnetite in the carbonatites ofSevvattur, North Arcot Tamil Nadu.Journal of African Earth Sciences, Vol. 19, No. 3, Apr. pp.297-304.India, Tamil NaduCarbonatite, Mineralogy
DS1995-1540
1995
Ramasamy, S.M.Ramasamy, S.M., Balaji, S.Remote sensing and Pleistocene tectonics of Southern Indian peninsulaInternational Journal of Remote Sensing, Vol. 16, No. 13, Sept. 10, pp. 2375-2392IndiaTectonics, Remote sensing
DS200512-0057
2005
Ramasamy, S.M.Balaji, S., Ramasamy, S.M.Remote sensing and resistivity image for the tectonic analysis of Biligirirangan region, peninsular India.Geocarto International, Vol. 20, 2, pp. 55-62.Asia, IndiaRemote sensing
DS200712-0867
2006
Ramasamy, S.M.Ramasamy, S.M.Remote sensing and active tectonics of South India.International Journal of Remote Sensing, Vol. 27, 20, pp. 4397-4431.IndiaTectonics
DS201511-1863
2015
Ramasar, V.Meissner, R., Ramasar, V.Governance and politics in the upper Limpopo River basin, South Africa.Geojournal, Vol. 80, 5, pp. 689-709.Africa, South AfricaMentions Venetia

Abstract: Everyday international political economy (EIPE) offers an opportunity to rethink the role of individuals and citizenry in shaping governance of natural resources. In South Africa, significant progress has been made by government in re-shaping water governance since the end of apartheid in the early 1990s. The role of government in water governance and water politics has thus been emphasised to a large degree. This study looks at historical material to assess the role that water politics and EIPE has played in shaping the use and management of water resources in the country. Case studies are analysed of two quaternary catchments, A63E and A71L in the Limpopo River Basin, to show how everyday actions by different actors has shaped the current waterscape in the basin. Four events, namely, the politics of the Middle Iron Age State at Mapungubwe; the development of the Mapungubwe National Park and World Heritage Site; the management of water for the De Beers Venetia Diamond Mine; and the establishment of the Coal of Africa Limited colliery are discussed in terms of the agential power at play during each event. The conclusions of the study are that EIPE and reflexive agential power are important factors in water governance that can sometimes be ignored through neoliberal institutionalism. In the current and future governance of water in South Africa they can offer an alternative view of the role and importance of actors and pathways for development.
DS1940-0127
1946
Ramashesham, S.Raman, C.V., Ramashesham, S.The Crystal Forms of Diamond and their SignificanceIndian Academy of Science Proceedings, Vol. 24, No. 1, PP.IndiaCrystallography, Diamond, Morphology, Natural Diamond
DS1996-1154
1996
Ramassamy, R.Ramassamy, R.Carbonatite dykes from Kudangulam area, near Cape Comorin, Tamil NaduJournal of Geological Society India, Vol. 48, No. 2, Aug. 1, pp. 221-IndiaCarbonatite
DS1984-0602
1984
Ramaswamy, R.Ramaswamy, R.Vogesite from Carbonatite Complex of Tiruppattur, Tamil Nadu India.Geological Society INDIA Journal, Vol. 25, No. 5, PP. 307-310.India, Tamil NaduMineralogy
DS1960-0634
1966
Ramberg, I.B.Barth, T.F.W., Ramberg, I.B.The Fen Circular ComplexWiley Interscience Publishing, PP. 225-257.Norway, ScandinaviaCarbonatite, Geology, Petrography
DS1970-0810
1973
Ramberg, I.B.Ramberg, I.B.Gravity Studies of the Fen Complex, Norway and Their Petrological Significance.Contributions to Mineralogy and Petrology, Vol. 38, PP. 115-134.Norway, ScandinaviaPetrology
DS201801-0050
2017
Rambolamanana, 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.
DS1860-0115
1870
Rambosson, J.Rambosson, J.Les Pierres Precieuses et les Principaux OrnamentsParis: Librairie De Firmin Didot Freres File Et Cie., 298P.GlobalGemology
DS2002-0894
2002
Ramboz, C.Kouzmanov, K., Bailly, L., Ramboz, C., Rouer, O., BnyMorphology, origin and infrared microthermometry of fluid inclusions in pyrite from Radka epithermal copperMineralium deposita, BulgariaCopper, gold, geochronology, Deposit - Radka, Srednogorie zone
DS1994-1430
1994
Ramchnadran, K.T.Ramchnadran, K.T., Porwal, B.Famous diamonds... mainly Indian... listed with weight and shape .. briefhistory.Indian Gemologist, Vol. 4, No. 1, pp. 20-3.GlobalHistory, Famous diamonds, diamonds notable
DS1970-0194
1970
Ramdas, A.K.Solin, S.A., Ramdas, A.K.Raman Spectrum of DiamondPhys. Rev. B., Vol. 1, No. 4, Feb. 15, pp. 1687-1698GlobalSpectroscopy, Diamond Morphology
DS1994-1431
1994
Ramdas, A.K.Ramdas, A.K.Vibrational band structure of diamondProperties and growth of diamond, G. Davies, pp. 13-22.GlobalDiamond, Bulk properties of natural isotope diamond
DS1983-0230
1983
Ramenskaya.Florovskaya, V.N., Korytov, F.YA., Ogloblina, A.I., Ramenskaya.Polycycle Aromatics in a Plutonic Lherzolite Xenolith and BasaltDoklady Academy of Science USSR, Earth Science Section., Vol. 262, No. 106, PP. 121-122.Russia, MongoliaRelated Rocks
DS201212-0791
2012
Rameseder, B.Wood, B.D., Rameseder, B., Scott Smith, B.H.The Victor diamond mine, northern Ontario Canada: successful mining of a reliable resource.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Ontario, AttawapiskatDeposit - Victor
DS201312-0982
2013
Rameseder, B.Wood, B.D., Scott Smith, B.H., Rameseder, B.The Victor diamond mine, northern Ontario, Canada: successful mining of a reliable resource.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 19-33.Canada, Ontario, AttawapiskatDeposit - Victor
DS201412-0988
2013
Rameseder, B.Wood, B.D., Scott Smith, B.H., Rameseder, B.The Victor diamond mine, northern Ontario, Canada: successful mining of a reliable resource.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 19-34.Canada, Ontario, AttawapiskatDeposit - Victor
DS1989-1442
1989
Ramesh, D.S.Sringesh, D., Rai, S.S., Ramesh, D.S., Gaur, V.K., Rao, C.V.R.Evidence for thick continental roots beneath South Indian shieldGeophysical Research Letters, Vol. 16, No. 9, September pp. 1055-1058IndiaMantle
DS1996-0788
1996
Ramesh, D.S.Krisna, V.G., Ramesh, D.S.A discussion on 410 km depth discontinuity: a sharpness estimate for near vertical reflection Vidale.Geophysical research Letters, Vol. 23, No. 18, Sept. 1, pp. 2573-MantleGeophysics -seismics, Discontinuity
DS2002-0905
2002
Ramesh, D.S.Kumar, M.R., Ramesh, D.S., Saul, J., Sarker, D., Kind, R.Crustal structure and upper mantle stratigraphy of the Arabian ShieldGeophysical Research Letters, Vol. 89, No. 8, April 15, pp. 83-Arabian Shield, North AfricaTectonics
DS2002-1303
2002
Ramesh, D.S.Ramesh, D.S., Kind, R., Yuan, X.Receiver function analysis of the North American crust and upper mantleGeophysical Journal International, Vol.150,1,pp.91-108.MantleGeophysics - seismics
DS2003-0812
2003
Ramesh, D.S.Li, X., Kind, R., Yuan, X., Sobolev, S.V., Hanka, W., Ramesh, D.S., Gu, Y.Seismic observation of narrow plumes in the oceanic upper mantleGeophysical Research Letters, Vol. 30, 6, p. 67. DOI10.1029/2002GLO15411MantlePlumes
DS200412-1130
2003
Ramesh, D.S.Li, X., Kind, R., Yuan, X., Sobolev, S.V., Hanka, W., Ramesh, D.S., Gu, Y., Dziewonski, A.M.Seismic observation of narrow plumes in the oceanic upper mantle.Geophysical Research Letters, Vol. 30, 6, p. 67. DOI10.1029/2002 GLO15411MantleGeophysics - seismics Plumes
DS200512-0588
2004
Ramesh, D.S.Kumar, M.R., Raju, P.S., Devi, E.U., Saul, J., Ramesh, D.S.Crustal structure variations in northeast India from converted phases.Geophysical Research Letters, Vol. 31, 17, Sept. 16, L17605IndiaTectonics
DS200512-0889
2005
Ramesh, D.S.Ramesh, D.S., Kumar, M.R., Devi, E.U., Raju, P.S., Yaun, X.Moho geometry and upper mantle images of northeast India.Geophysical Research Letters, Vol. 32, 14, July 28, L14301IndiaGeophysics - seismics
DS200612-1312
2006
Ramesh, D.S.Singh, A., Kumar, M.R., Raju, P.S., Ramesh, D.S.Shear wave anisotropy of the northeast Indian lithosphere.Geophysical Research Letters, Vol. 33, 16, August 28, L16302.IndiaGeophysics - seismics
DS201012-0137
2010
Ramesh, D.S.Das Sharma, S., Ramesh, D.S., Li, X., Yuan, B., Sreenivas, B., Kind, R.Response of mantle transition zone thickness to plume bouyancy flux.Geophysical Journal International, Vol. 180, 1, pp. 49-58.MantlePlume
DS201312-0184
2013
Ramesh, D.S.Das Sharma, Ramesh, D.S.Imaging mantle lithosphere for diamond prospecting in southeast India.Lithosphere, Vol. 5, no. 4, pp. 331-342.IndiaTectonics
DS1999-0586
1999
Ramesh, R.Ray, J.S., Ramesh, R., Pande, K.Carbon isotopes in Kerguelen plume derived carbonatites: evidence for recycled inorganic carbon.Earth and Planetary Science Letters, Vol. 170, No. 3, July 15, pp. 205-14.GlobalCarbonatite, Carbon cycle
DS2000-0802
2000
Ramesh, R.Ray, J.S., Ramesh, R., Pande, Trivedi, Shukla, PatelIsotope and rare earth element chemistry of carbonatite alkaline complexes of Deccan volcanic: implications...Journal of Asian Earth Science, Vol. 18, No.2, Apr. pp.177-94.India, Gujarat, WesternCarbonatite, Magmatism, alteration
DS200512-1141
2005
Ramesh, R.Viladkar, S.G., Ramesh, R., Avasia, R.K., Pawaskar, P.B.Extrusive phase of carbonatite alkalic activity in Amba Dongar Complex, Chhota Udaipur Gujarat.Journal of the Geological Society of India, Vol. 66, 3, pp. 273-276.IndiaCarbonatite
DS200612-1138
2006
Ramesh, R.Ray, J., Ramesh, R.Stable carbon and oxygen isotopic compositions of Indian carbonatites.International Geology Review, Vol. 48, 1, Jan. pp. 17-45.IndiaGeochronology
DS1991-0117
1991
Ramesh Babu, N.Bhaskara Rao, D., Ramesh Babu, N.A FORTRAN-77 computer program for three dimensional analysis of gravity anomalies with variable density contrastComputers and Geosciences, Vol. 17, No. 5, pp. 655-668GlobalComputer, Program -gravity
DS202003-0358
2019
Rameshchandra Phani, P.Rameshchandra Phani, P.Restoring the past glory of diamond mining in south India - A plausible case of diamondiferous Wajrakarur kimberlite pipe clusters with geochemical evidences.International Journal of Mining and Geo-Engineering, 11p. PdfIndiadeposit - Wajrakarur

Abstract: A plausible case of collective and economical mining of diamondiferous kimberlite deposits of Wajrakarur and adjoining places in Andhra Pradesh, southern India along with the whole-rock geochemical evidences in support of their diamond potentiality are discussed in this article. The kimberlites/lamproites are mantle-derived ultrabasic rocks which rarely carry diamonds from mantle to the earth’s surface through carrot-shaped intrusions referred to as pipes. Even though few hundreds of diamondiferous kimberlite pipes were discovered in India so far, there is no other production unit than Panna diamond mine in the country where primary rock is mined. In ancient India, diamond mining in south India in the Krishna river valley was well-known to the world fascinated by famous gemstones like Koh-I-Noor, Hope, Darya-e-Noor, Noor-ul-ain etc. which were mainly extracted from alluvium or colluvium in Krishna river valley. Having bestowed with more than 45 kimberlite pipes, the Wajrakarur kimberlite field (WKF) forms a favourable region for initiating diamond mining in the country. Geochemically, majority of the WKF show low TiO2 content and considerably high diamond grade (DG) values (>3) except some pipes viz., P-5 (Muligiripalli), P-13 (Tummatapalli) and P-16 (Pennahobilam) are barren due to high TiO2 and ilmenite contents. The TiO2 content (0.66-6.62 wt%) is inversely proportional to the DG (3.33 to 22.13). The DG value of some of the WKF pipes is close to that of Panna (8.36). The cationic weight% values clearly portray the diamondiferous nature of these deposits. The WKF pipes were also proved to be diamondiferous by exploratory drilling and bulk sample processing results by the government organisations. In southern India, due to several reasons, diamond mining has not seen its initiation and impetus till now although it records a considerable number of fertile kimberlite pipes at Wajrakarur, Lattavaram, Chigicherla, Timmasamudram etc. Though the majority of WKF diamondiferous kimberlite deposits in Wajrakarur are small in their areal extent (0.06-4.48 Ha) some of them are large (>10 Ha up to 120 ha). They occur in close proximity to each other offering feasibility for collective mining and winning the precious stone through a central processing unit by deploying the latest processing technologies. The geographic conditions of this region such as availability of human resources, water resources, vast open lands, wind power generation etc. also support to initiate mining of kimberlite pipes in this area. The availability of rough diamonds produced from local mines will make the polishing industry to meet its business needs during circumstances of the shortage of rough stone influx from foreign. Hence, although it demands liberal investments, reviving diamond mining in southern India can be materialised with a meticulous evaluation of these deposits ascertaining profitability. This will certainly help to restore the past glory of diamond mining in the southern part of the subcontinent.
DS2002-0652
2002
RamezaniHanson, R., Pancake, J., Crowley, J., Ramezani, Bowring, Dalziel, GoseCorrelation of 1.1 GA large igneous provinces on the Laurentia and Kalahari Cratons:Geological Society of America Annual Meeting Oct. 27-30, Abstract p. 561.South Africa, Botswana, Zimbabwe, OntarioTectonics, Gondwana
DS200412-0788
2004
Ramezani, J.Hanson, R.E., Gose, W.A., Crowley, J.L., Ramezani, J., Bowring, S.A., Bullen, D.S., Hall, R.P., Pancake, J.A.Paleoproterozoic intraplate magmatism and basin development on the Kaapvaal Craton: age, paleomagnetism and geochemistry of 1.93South African Journal of Geology, Vol. 107, 1/2, pp. 233-254.Africa, South AfricaCraton, tectonics, magmatism
DS200712-0097
2007
Ramezani, J.Bowring, S.A., Crowley, J.L., Ramezani, J., McLean, N., Condon, D., Schoene, B.High precision U Pb zircon geochronology: progress and potential.Plates, Plumes, and Paradigms, 1p. abstract p. A117.MantleGeochronology - EARTHTIME
DS2002-1304
2002
Ramiengar, A.S.Ramiengar, A.S.Carbonatite bodies of Dhanota Dhancholi area in Mahendragarh District, HaryanaJournal of the Geological Society of India, Vol. 60, 5, pp. 587-8.IndiaBrief - note, Carbonatite
DS1994-1432
1994
Ramires, A.P.Ramires, A.P., et al.Magnetic susceptibility of molecular carbon: nanotubes and fulleriteScience, Vol. 265, No. 5168, July 1, pp. 84-85.GlobalCarbon, Fullerine
DS201312-0200
2013
Ramirez, C.De Moor, M., Fischer, T.P., King, P.L., Botcharnikov, R.E., Hervig, R.L., Hilton, D.R., Barry, P.H., Mangasini, F., Ramirez, C.Volatile rich silicate melts from Oldoinyo Lengai volcano (Tanzania): implications for carbonatite genesis and eruptive behavior.Earth and Planetary Science Letters, Vol. 361, pp. 379-390.Africa, TanzaniaDeposit - Oldoinyo Lengai
DS202103-0405
2021
Ramirez, K.Schmitz, M., Ramirez, K., Mazuera, F., Avila, J., Yegres, L., Bezada, M., Levander, A.Moho depth map of northern Venezuela on wide-angle seismic studies.Journal of South American Earth Sciences, Vol. 107, 103088, 17p. PdfSouth America, VenezuelaGeophysics - seismics

Abstract: As part of the lithosphere, the crust represents Earth's rigid outer layer. Some of the tools to study the crust and its thickness are wide-angle seismic studies. To date, a series of seismic studies have been carried out in Venezuela to determine in detail the crustal thickness in the southern Caribbean, in the region of the Caribbean Mountain System in northern Venezuela, as well as along the Mérida Andes and surrounding regions. In this study, a review of the wide-angle seismic data is given, incorporating new data from the GIAME project for western Venezuela, resulting in a map of Moho depth north of the Orinoco River, which serves as the basis for future integrated models. Differences in Moho depths from seismic data and receiver function analysis are discussed. From the Caribbean plate, Moho depth increases from 20 to 25 km in the Venezuela Basin to about 35 km along the coast (except for the Falcón area where a thinning to less than 30 km is observed) and 40-45 km in Barinas - Apure and Guárico Basins, and Guayana Shield, respectively. Values of more than 50 km are observed in the Maturín Basin and in the southern part of the Mérida Andes.
DS1860-0447
1884
Ramirez, S.Ramirez, S.Noticia Historica de la Riqueza Mineral de Mexico Y de Su Actual Estado de Exploitacion.Mexico City: Officina Tipografica De la Secretaria De Foment, 768P.MexicoGemology
DS201908-1806
2019
Ramiz, M.M.Ramiz, M.M., Mondal, M,E.A., Farooq, S.H.Geochemistry of ultramafic-mafic rocks of the Madawara ultramafic complex in the southern part of the Bundelkhand craton, Central Indian Shield: implications for mantle sources and geodynamic setting.Geological Journal, Vol. 54, 4, pp. 2185-2207.Indiacraton

Abstract: Detailed field, petrography and whole?rock geochemical study was carried out in order to constrain the mantle sources and geodynamic setting of the Madawara Ultramafic Complex (MUC) of the Bundelkhand Craton. Studies reveal that there are two types of ultramafic rocks: (a) high?Mg ultrabasic/basic rocks and (b) undeformed ultramafic-mafic plutonic rocks. The high?Mg ultrabasic/basic rocks have undergone severe low?grade (greenschist) metamorphism and are characterized by stringer and veinlet structures of talc-tremolite-actinolite schists with alternate layers of serpentinites showing comparatively higher SiO2 (46.1-49.4 wt%), lower MgO (24.6-26.2 wt%), and higher Al2O3 (4.58-7.06 wt%) and CaO (2.72-6.77 wt%) compared to the undeformed ultramafic rocks. The undeformed ultramafic rocks (mainly harzburgite, lherzolite, and olivine websterite) are characterized by globular structures and have lower SiO2 (40-44.1 wt%), higher MgO (30.4-38 wt%) and lower Al2O3 (1.84-4.03 wt%) and CaO (0.16-3.14 wt%). The undeformed mafic rocks (mainly gabbro) occur as small pockets within the undeformed ultramafic rocks as well as independent outcrops. Limited variation in Nb/Th against Nb/Yb along with negative Nb?Ti anomalies of all the rock types in the multi?element diagram reveals the significant role of the metasomatized mantle in their genesis. All the rocks show enrichment in light rare earth element and large?ion lithophile elements compared to heavy rare earth elements and high?field strength elements. The geochemical characteristics coupled with Ce/Yb versus Ce variation of the rocks of MUC point towards two different sources for their genesis. The high?Mg ultrabasic/basic rocks are derived from partial melting of metasomatized mantle at shallow depth, while the undeformed ultramafic rocks were formed as a result of asthenospheric upwelling from a greater depth that induced the melting in the overlying lithosphere. Gabbro rocks represent the last and most evolved phase of the complex. Geochemical signatures suggest that the rocks of MUC were formed in a continental arc setting.
DS1985-0739
1985
Ramkin, A.H.Wooley, A.R., Ramkin, A.H., Elliott, C.J., Bishot, A.C., Niblett, D.Carbonatite dykes from the Richat dome, Mauritania and genesis of thedomeIndian Mineralogist, Sukheswala Volume, pp. 189-207MauritaniaCarbonatite
DS200712-0286
2007
Ramnko, E.F.Egorov, K.N., Ramnko, E.F., Podvysotsky, V.T., Sabulukov, S.M., Garanin, V.K., Dyakonov, D.B.New dat a on kimberlite magmatism in southwestern Angola.Russian Geology and Geophysics, Vol. 48, 4, pp. 323-336.Africa, AngolaMagmatism - kimberlites
DS1998-0906
1998
RamoLuttinen, A.V., Ramo, HuhmaNeodynmium and strontium isotopic and trace element composition of aMesozoic CFB suite from Dronning Maud Land: lithosphere and asthenosphere ...Karoo magmatismGeochimica et Cosmochimica Acta, Vol. 62, No. 15, pp. 2701-14.AntarcticaLithosphere, mantle
DS1994-1433
1994
Ramo, O.T.Ramo, O.T.1.3 Ga mafic magmatism of the St. Francois Mountains: implications for mantle composition mid-continentMineralogical Magazine, Vol. 58A, pp. 754-55. AbstractMissouriMafic magmatism, Geochronology
DS2001-0652
2001
Ramo, O.T.Landen, L.S., Ramo, O.T.Silicic magmatism and Early Paleoproterozoic continental rifting, east FIn land and adjacent RussiaGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.81.abstract.Finland, RussiaMagmatism
DS200512-1110
2005
Ramo, O.T.Upton, B.G.J., Ramo, O.T., Heaman, L.M., Blichert-Toft, J., Kalsbeek, F., Barry, T.L., Jepsen, H.F.The Mesoproterozoic Zig-Zag Dal basalts and associated intrusions of eastern North Greenland: mantle plume lithosphere interaction.Contributions to Mineralogy and Petrology, Vol. 149, 1, pp. 40-56.Europe, GreenlandTectonics
DS200612-0791
2005
Ramo, O.T.Lehtinen, M., Nurmi, P., Ramo, O.T.Precambrian geology of Finland.Elsevier , 750p. $ 190.00Europe, FinlandBook - geology
DS201312-0928
2013
Ramo, O.T.Upton, B.G.J., Macdonald, R., Odling, N., Ramo, O.T., Baginski, B.Kungnaat, revisited. A review of five decades of research into an alkaline complex in South Greenland, with new trace element and Nd isotopic data.Mineralogical Magazine, Vol. 77, 4, pp. 523-550.Europe, GreenlandKungnaat
DS200612-0997
2004
Ramo, T.O'Brien, H., Ramo, T., Gehor, S.Carbonatite-kimberlite-alkaline rock field trip to southern and central Finland.Siilinjarvi, Kaavi-Kuopio, Kuhmo, IivaaraFinland Field Trip Guidebook June 2-4, 2004, 30p.Europe, FinlandGuidebook
DS200412-1222
2004
Ramokate, L.V.Mapeo, R.B.M., Armstrong, R.A., Kampunzu, A.B., Ramokate, L.V.SHRIMP U Pb zircon ages of granitoids from the western domain of the Kaapvaal Craton, southeastern Botswana: implications for crSouth African Journal of Geology, Vol. 107, 1/2, pp. 159-172.Africa, BotswanaGeochronology, tectonics
DS202104-0602
2021
Ramokgaba, L.Ramokgaba, L., Le Roex, A., Robey, J.Phlogopite-rich and phlogopite-poor kimberlite intrusions within the Du Toitspan kimberlite pipe, South Africa: petrogenetic relationships and localised source heterogeneity.Lithos, in press available, 35p. PdfAfrica, South Africadeposit - Du Toitspan

Abstract: Samples from three petrographically distinct, intrusive kimberlite bodies and associated kimberlite dykes from the eastern lobe of the Du Toitspan kimberlite pipe, Kimberley, South Africa, have been analysed for their bulk rock major and trace element compositions and their olivine and phlogopite compositions. The two dominant intrusive bodies (D13, D14) are distinguished by the one (D13) being phlogopite-rich and best classified as a macrocrystic hypabyssal phlogopite kimberlite, and the other (D14) being phlogopite-poor and best classified as a macrocrystic hypabyssal monticellite kimberlite. The minor D17 intrusive body is classified as a macrocrystic transitional hypabyssal serpentinized phlogopite kimberlite. The associated kimberlite dykes range texturally from aphanitic to macrocrystic and are classified as calcite kimberlites. The major kimberlite intrusions and their associated dykes show no evidence of crustal contamination and are characterised by broadly overlapping geochemistry except for distinctly higher K2O (> 2?wt%) and Al2O3 (>3?wt%) and flattening HREE patterns (Gd/YbN?=?6.5-7.0) in the D13 - phlogopite kimberlite compared to the D14 - monticellite kimberlite and the calcite kimberlite dykes (Gd/YbN?=?9.6-12.1). These distinguishing geochemical features of the D13 - phlogopite kimberlite are comparable to typical Group II kimberlites in southern Africa. However, their diagnostic incompatible trace element ratios (for example, Th/Nb, La/Nb, Ce/Pb, and Ba/Nb) are instead comparable to other kimberlite intrusions analysed in this study and to southern African Group I kimberlites in general. Semi-quantitative modelling suggests that these kimberlite intrusions could have derived by low (<1%) degrees of partial melting of a source region that is enriched in LREE (Lan?=?~6.1; Ybn?~?1.47) comparable to metasomatised peridotites from the underlying lithospheric mantle. The composition of the D13 phlogopite kimberlite is consistent with a partial melt of a modally metasomatised source containing a higher proportion of residual clinopyroxene relative to garnet (compared to that giving rise to the D14 monticellite kimberlite and calcite kimberlite dykes), as well as accessory amounts of phlogopite, i.e. a garnet phlogopite peridotite (GPP). The absence of K-anomalies on primitive mantle normalized diagrams for the D13 phlogopite kimberlite requires that phlogopite was not a residual phase during partial melting and was exhausted shortly before or at the moment of melt segregation. The higher Gd/Yb ratios and lower K2O in the D14 monticellite kimberlite and calcite kimberlite dykes can be explained by partial melting of a cryptically metasomatized, phlogopite - free, garnet peridotite (GP) source, containing a higher proportion of garnet relative to clinopyroxene. The low absolute K and strong negative K-anomaly on primitive mantle normalized diagrams for the D14 monticellite kimberlite were inherited from a source region that previously experienced cryptic metasomatism by a differentiated fluid already carrying a negative K-anomaly.
DS1860-0907
1895
Ramond, M.G.Ramond, M.G.Annuaire Geologique UniverselleParis, Vol. X, 1893, PP. 595-654.IndiaHistory
DS1989-1251
1989
Ramon-Lluch, R.Ramon-Lluch, R., Martinez-Torres, L.M., Eguiluz, L.RAFOLD: a BASIC program for the geometric classification of foldsComputers and Geosciences, Vol. 15, No. 6, pp. 989-996GlobalComputer, Program -RAFOLD.
DS1991-1610
1991
Ramos, .N.Smith, C.B., Ramos, .N., Hatton, C.J., Horsch, H., DamarupurshadEclogite xenolith with exsolved sanidine from the Proterozoic Kuruman kimberlite province, northern Cape, R.S.A.Proceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 383-384South AfricaZero, geochronology, xenoliths, Eclogite xenoliths
DS200712-0868
2006
Ramos, F.C.Ramos, F.C., Reid, M.R., Sims, K.W.W.Re-evaluating the mantle structure underlying the southwestern US.Geochimica et Cosmochimica Acta, In press availableUnited States, Colorado PlateauGeochronology
DS201212-0581
2012
Ramos, F.C.Reid, M.R., Boucher, R.A., Ichert-Toft, J., Levander, A., Liu, K., Miller, M.S., Ramos, F.C.Melting under the Colorado Plateau, USA.Geology, Vol. 40, 5, pp. 387-390.United States, Colorado PlateauMelting
DS200812-0334
2008
Ramos, J.M.F.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
DS1950-0455
1959
Ramos, J.R.Barbosa, O., Ramos, J.R.Territorio de Rio Blanco; Aspectos Principais de Geomorfologia, Da Geologia E das Possibilidades Minerais de Sua Zona SetentrionalBol. Div. Geol. Mineral, No. 196, 49P.South America, BrazilBlank
DS200512-1137
2004
Ramos, M.L.S.Ventura Santos, R., Souza de Alvarenga, C.J., Babinski, M., Ramos, M.L.S., Cukrov, N., Fonsec, M.A., Da NorbregaCarbon isotopes of Mesoproterozoic Neoproterozoic sequences from southern Sao Francisco craton and Aracuai Belt, Brazil: paleogeorgraphic implications.Journal of South American Earth Sciences, Vol. 18, 1, Dec. 30, pp. 27-39.South America, BrazilGeomorphology, glaciation, geochronology,carbonatites
DS1996-1173
1996
Ramos, R.C.Reid, M.R., Ramos, R.C.Chemical dynamics of enriched mantle in the southwestern United States:thorium isotope evidence.Earth and Planetary Science Letters, Vol. 138, No. 1/4, Feb. 1, pp. 67-82.Nevada, Arizona, ColoradoGeochemistry, geochronology, Mantle geodynamics
DS1988-0562
1988
Ramos, V.A.Ramos, V.A.Late Proterozoic Early Paleozoic of South America - a collisional history.Episodes, Vol. 11, No. 3, Sept. pp. 168-173.Paraguay, BrazilGondwana, Tectonics
DS1989-0755
1989
Ramos, V.A.Kay, S.M., Ramos, V.A., Mpodozis, C., Sruoga, P.Late Paleozoic to Jurassic silicic magmatism at theGondwanamargin:analogy to the middle Proterozoic in North America?Geology, Vol. 17, No. 4, April pp. 324-328MidcontinentTectonics
DS1989-1252
1989
Ramos, V.A.Ramos, V.A.The birth of southern South AmericaAmerican Scientist, Vol. 77, No. 5, Sept-October pp. 444-450South AmericaTectonics, Overview
DS1993-0956
1993
Ramos, V.A.Mahlburg Kay, S., Ramos, V.A., Marquez, M.Evidence in Cerro Pampa volcanic rocks for slab melting prior to Ridge-Trench collision in southern South AmericaJournal of Geology, Vol. 101, No. 6, November pp. 703-714Argentina, PatagoniaAdakite flows, Magmatic, melt
DS1996-1155
1996
Ramos, V.A.Ramos, V.A., Cegarra, M., Cristallini, E.Cenozoic tectonics of the High Andes of west central Argentin a (30- 36 d Slatitude)Tectonophysics, Vol. 259, No. 1-3, June 30, pp. 185-200ArgentinaTectonics
DS2002-0565
2002
Ramos, V.A.Giambiagi, L.B., Ramos, V.A.Structural evolution of the Andes in a transitional zone beneath flat and normal subduction 33-33 ....Journal of South American Earth Sciences, Vol.15,1,Apr.pp.101-116.Argentina, Chile, AndesTectonics
DS2002-1305
2002
Ramos, V.A.Ramos, V.A., Cristallini, E.O., Perez, D.J.The Pampean flat slab of the central AndesJournal of South American Earth Sciences, Vol.15,1,Apr.pp.59-78.Chile, AndesSubduction, Slab
DS201012-0609
2010
Ramos, V.A.Ramos, V.A., Vukovich, G., Martino, R., Otamendi, J.Pampia: a large cratonic block missing in the Rodinia supercontinentJournal of Geodynamics, Vol. 50, 3-4, pp. 243-255.South AmericaCraton, crustal evolution
DS1991-1396
1991
Ramos, Z.Ramos, Z., Skinner, E.M.W., Bristow, J.W., Robinson, D.N.Kimberlites and the mantle in South AfricaXiii International Gemmological Conference Held South Africa, Stellenbosch, 2p.abstractSouth AfricaMantle, Diamond genesis
DS1998-1648
1998
Ramos, Z.Zinngrebe, E., Jacob, D., Ramos, Z., Smith, C.B.A model for eclogite peridotite interactions: activity driven with evidence from Zero eclogiteMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1705-6.South AfricaSubduction, eclogite, Deposit - Zero
DS1994-1434
1994
Ramos, Z.N.Ramos, Z.N., Smith, C.B., Horsch, H.E.Eclogite xenoliths from the Zero kimberlite, Kuruman area, RSAInternational Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 8-10.South AfricaEclogite xenoliths, Deposit -Zero
DS202007-1131
2020
Ramotoroko, C.Chisenga, C., Van der Meijde, M., Yan, J., Fadel. I., Atekwana, E.A., Steffen, R., Ramotoroko, C.Gravity derived crustal thickness model of Botswana: its implication for the Mw 6.5 April 3, 2017, Botswana earthquake. Tectonophysics, Vol. 787, 228479 12p. PdfAfrica, Botswanageophysics - gravity

Abstract: Botswana experienced a Mw 6.5 earthquake on 3rd April 2017, the second largest earthquake event in Botswana's recorded history. This earthquake occurred within the Limpopo-Shashe Belt, ~350 km southeast of the seismically active Okavango Rift Zone. The region has no historical record of large magnitude earthquakes or active faults. The occurrence of this earthquake was unexpected and underscores our limited understanding of the crustal configuration of Botswana and highlight that neotectonic activity is not only confined to the Okavango Rift Zone. To address this knowledge gap, we applied a regularized inversion algorithm to the Bouguer gravity data to construct a high-resolution crustal thickness map of Botswana. The produced crustal thickness map shows a thinner crust (35-40 km) underlying the Okavango Rift Zone and sedimentary basins, whereas thicker crust (41-46 km) underlies the cratonic regions and orogenic belts. Our results also show localized zone of relatively thinner crust (~40 km), one of which is located along the edge of the Kaapvaal Craton within the MW 6.5 Botswana earthquake region. Based on our result, we propose a mechanism of the Botswana Earthquake that integrates crustal thickness information with elevated heat flow as the result of the thermal fluid from East African Rift System, and extensional forces predicted by the local stress regime. The epicentral region is therefore suggested to be a possible area of tectonic reactivation, which is caused by multiple factors that could lead to future intraplate earthquakes in this region.
DS1994-1435
1994
Ramoz, Z.Ramoz, Z.Eclogite xenoliths from the Kuruman kimberlites, South AfricaUniversity of Witwatersrand, MSc. thesisSouth AfricaXenoliths, Thesis
DS201112-0867
2011
RampilovRipp, G.S., Doboshkevich, A.G., Ripp, G.S., Lastochkin, Izbrodin, RampilovA way of carbonatite formation from alkaline gabbros, Oshurkovo massif.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.39-41.RussiaOshurkovo
DS201112-0868
2011
RampilovRipp, G.S., Doboshkevich, A.G., Ripp, G.S., Lastochkin, Izbrodin, RampilovA way of carbonatite formation from alkaline gabbros, Oshurkovo massif.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.39-41.RussiaOshurkovo
DS1994-1436
1994
Rampino, .R.Rampino, .R.Tillites, diamictites and ballistic ejecta of large impactsJournal of Geology, Vol. 102, No. 4, July pp. 439-456GlobalSedimentology, Glaciology
DS1984-0603
1984
Rampino, M.R.Rampino, M.R., Stothers, R.B.Geological Rhythms and Cometary ImpactsNasa/national Technical Information Service, No. N84-32327, 22P.GlobalCraters, Tectonics
DS1991-0204
1991
Rampino, M.R.Caldeira, K., Rampino, M.R.The Mid-Cretaceous super flume, carbon dioxide, and global warmingGeophysical Research Letters, Vol. 18, No. 6, June pp. 987-990GlobalCarbon cycle, Climates
DS1991-0205
1991
Rampino, M.R.Caldeira, K., Rampino, M.R.The Mid Cretaceous super plume: carbon dioxide, and global warmingGeol. Res. Let., Vol. 18, No. 6, June pp. 987-90.MantlePlumes
DS1993-1280
1993
Rampino, M.R.Rampino, M.R., Caldeira, K.Major episodes of geologic change: correlations, time structure and possible causesEarth and Planetary Science Letters, Vol. 114, No. 2-3, January pp. 215-228GlobalTectonics, Mantle, continent, Rifting
DS201312-0731
2013
Rampino, M.R.Rampino, M.R., Prokoph, A.Are mantle plumes periodic?EOS Transaction of AGU, Vol. 94, 12, March 19, pp. 113-120.MantlePlume cycles
DS1991-1397
1991
Rampone, E.Rampone, E., Bottazzi, P., Ottolini, L.Complementary Titanium and Zirconium anomalies in orthopyroxene and clinopyroxene from mantle peridotitesNature, Vol. 354, No. 6354, Dec. 19, 26 pp. 518-520MantleClinopyroxenes, titanium, zirconium, Peridotites
DS1999-0626
1999
Rampone, E.Scambelluri, M., Rampone, E.magnesium metasomatism of oceanic gabbros and its control on Ti clinohumite formation during eclogization.Contributions to Mineralogy and Petrology, Vol. 135, No. 1, pp. 1-17.GlobalMetasomatism, Eclogites
DS2001-0919
2001
Rampone, E.Piccardo, G.B., Rampone, E.Strongly depleted Mid Ocean Ridge Basalt (MORB) melts at extensional settings: peculiar mafic ultramafic intrusive suiteMt. MaggioreGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p. 118.abstract.France, CorsicaPeridotite
DS200412-1617
2004
Rampone, E.Rampone, E., Romairone, A., Hofmann, A.W.Contrasting bulk and mineral chemistry in depleted mantle peridotites: evidence for reactive porous flow.Earth and Planetary Science Letters, Vol. 218, 3-4, Feb. 15, pp. 491-506.Europe, AlpsMineral chemistry - not specific to diamonds
DS1920-0245
1925
Ramsay, A.Ramsay, A.In Search of the Precious StoneNew York: A. Ramsay And Co., 50P.GlobalDiamonds Notable, Kimberley
DS1994-1713
1994
Ramsay, D.A.Sturt, B.A., Melezhik, V.A., Ramsay, D.A.Early Proterozoic regolith at Pasvik, northeast Norway: paleoenvironmental implications for the Baltic ShieldTerra Nova, Vol. 6, No. 6, pp. 618-632NorwayPaleoclimatology, Sedimentology -regolith
DS1986-0506
1986
Ramsay, R.Lucas, H., Ramsay, R., Hall, A.E., Smith, C.B., Sobolev, N.V.Garnets from West Australian kimberlites and associated rocksProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 270-272AustraliaBlank
DS1995-1541
1995
Ramsay, R.Ramsay, R.Significance of indicator minerals in the exploration and evaluation Of kimberlitic rocks.University of West. Australian Key Centre, held Feb. 15, 16th., 5p.AustraliaDiamond exploration, Indicator minerals, geochemistry
DS1995-1542
1995
Ramsay, R.Ramsay, R.The discovery of the Lower Bulgurri kimberlite - a new diamondiferous fissure in the North Kimberley.Prospectors and Developers Association of Canada (PDAC) Preprint, 6p.Australia, Western AustraliaGeology, Deposit -Lower Bulgurri
DS1998-1421
1998
Ramsay, R.Sumner, J., Wilkes, J., Robins, J., Ramsay, R.A geophysical case study of the Ashmore kimberlite cluster, North KimberleyProvince, Western Australia.Australian Society of Exploration Geophysicists (ASEG) International, p. 109. abstractAustraliaGeophysics, Deposit - Ashmore
DS1998-1471
1998
Ramsay, R.Tompkins, L., Taylor, W., Ramsay, R., Armstrong, R.The mineralogy and geochemistry of the Kamafugitic Tres Barras intrusion, Mat a da Corda, Minas Gerais, Brasil.7th International Kimberlite Conference Abstract, pp. 920-2.Brazil, Minas GeraisLeucitites, kamafugites, Deposit - Tres Barras
DS201012-0258
2010
Ramsay, R.Gwalani, L.G., Rogers, K.A., Demeny, A., Groves, D.L., Ramsay, R., Beard, A., Downes, P.J., Eves, A.The Yungul carbonatite dykes associated with the epithermal fluorite deposit at Speewah, Kimberley, Australia: carbon and oxygen isotope constraints originMineralogy and Petrology, Vol. 98, 1-4, pp. 123-141.AustraliaCarbonatite
DS201112-0230
2011
Ramsay, R.Czuppon, G., Gwalani, L.G., Demeny, A., Ramsay, R., Rogers, K., Eves, A., Szabo, Cs.C, O, H isotope compositions of the Wilmott and Yungul carbonatites and the associated fluorites in the Speewah dome, Kimberley region, Australia.Goldschmidt Conference 2011, abstract p.711.AustraliaCarbonatite
DS1989-0901
1989
Ramsay, R.R.Lucas, H., Ramsay, R.R., Hall, A.E., Smith, C.B., Sobolev, N.V.Garnets from Western Australian kimberlites and related rocksGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 809-819AustraliaLamproite, Heavy minerals, Geochemist
DS1990-1211
1990
Ramsay, R.R.Ramsay, R.R., Rock, N.M.S.Comparative garnet, pyroxene, chromite and magnesium-ilmenite xenocryst compositions in selected kimberlitic sources and their relevance to diamondexplorationGeological Society of Australia Abstracts, No. 25, No. A12.11 pp. 243-244. AbstractAustraliaMantle nodules, Garnet analyses -Xenocrys
DS1991-1740
1991
Ramsay, R.R.Tompkins, L.A., Ramsay, R.R.The Boa Esperanca and Cana Verde pipes, Corrego d'Anta, Minas Gerais, BrasilProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 429-431Brazil, Inga, Quartel, Portugal, Minas Gerais, Boa EsperancaBambui province, lineament, structure, craton, Mineral chemistry
DS1993-1281
1993
Ramsay, R.R.Ramsay, R.R.Geochemistry of diamond indicator mineralsUniversity of Western Australia, Ph.d. thesisAustraliaGeochemistry -diamonds, Thesis
DS1994-1437
1994
Ramsay, R.R.Ramsay, R.R., Edwards, D., Taylor, W.R., Rock, N.M.S., Griffin, B.J.Compositions of garnet, spinel Aries Diamondiferous kimberlite pipe, Kimberley Block, implications for explJournal of Geochem. Exploration, Vol. 51, No. 1, Apr. pp. 59-78.AustraliaGeochemistry, Deposit -Aries
DS1994-1438
1994
Ramsay, R.R.Ramsay, R.R., Tompkins, L.A.The geology, heavy mineral concentrate mineralogy, diamond prospectivity Of the Boa Esperanca and Cana Verde pipes.Proceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 329-345.Brazil, Minas Gerais, Mato GrossoGeochemistry, Deposit -Boa Esperanca, Cana Verde
DS1994-1628
1994
Ramsay, R.R.Smith, C.B., Lucas, H., Hall, A.E., Ramsay, R.R.Diamond prospectivity and indicator mineral chemistry: a western Australianperspective.Proceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 312-318.AustraliaGeochemistry, Diamond exploration
DS1994-1793
1994
Ramsay, R.R.Towie, N.J., Bush, M.D., Manning, E.R., Marx, M.R., Ramsay, R.R.The Aries Diamondiferous kimberlite pipe central Kimberley Block, westernAustralia: exploration, setting and evaluation.Proceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 319-328.AustraliaDiamond exploration, Deposit -Aries
DS1996-1156
1996
Ramsay, R.R.Ramsay, R.R.Kimberlite discoveries in the northern Kimberleys, Western AustraliaAustralia Nat. University of Diamond Workshop July 29, 30., 2p.AustraliaKimberley Block, Halls Creek, Exploration -brief overview
DS1920-0082
1921
Ramsay, W.Ramsay, W.En Melilitforande Djupbergart Fran Turja Pa Sydsidan Av Kolahalvon.Geol. Foren. Forhandl., Vol. 43, P. 488.Norway, ScandinaviaUltramafic And Related Rocks
DS1960-0610
1965
Ramsay, W.Sturt, B.A., Ramsay, W.The Alkaline Complex of the Breivikbotn Area, Soroy, NorwayNorges Geol. Unders. Skr., No. 231Norway, ScandinaviaUltramafic And Related Rocks
DS2003-0575
2003
Ramsay, W.R.H.Hell, A.J., Ramsay, W.R.H., Rheinberger, G., Pooley, S.The geology, age, mineralogy and near surface features of the Merlin kimberlites8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractAustraliaKimberlite geology and economics, Deposit - Merlin
DS200412-1618
2003
Ramsay, W.R.H.Ramsay, W.R.H., Hell, A., Reinberger, G., Pooley, S.The geology, age, near surface features and mineralogy of the Merlin kimberlite field, Northern Territory, Australia.Geological Society of Australia Abstracts, Vol. 70, p. 54. 1p.Australia, Northern TerritoryDeposit overview - Merlin
DS1990-1212
1990
Ramsden, A.R.Ramsden, A.R., French, D.H.Routine trace -element capabilities of electron microprobe analysis in mineralogical investigations: an empirical evaluation of performance usingspectroM.Canadian Mineralogist, Vol. 28, Pt. 1, March pp. 171-180GlobalMircoprobe analysis, Spectrometry
DS1993-1282
1993
Ramsden, A.R.Ramsden, A.R., French, D.H., Chalmers, D.I.Volcanic hosted rare-metals deposit at Brockman, Western AustraliaMineralium Deposita, Vol. 28, pp. 1-12AustraliaRare earths, Deposit -Brockman
DS201712-2681
2018
Ramsden, F.Creus, P.K., Basson, I.J., Stoch, B., Mogorosi, O., Gabanakgosi, K., Ramsden, F., Gaegopolwe, P.Structural analysis and implicit 3D modelling of Jwaneng mine: insights into deformation of the Transvaal Supergroup in SE Botswana.Journal of African Earth Sciences, Vol. 137, pp. 9-21.Africa, Botswanadeposit - Jwaneng

Abstract: Country rock at Jwaneng Diamond Mine provides a rare insight into the deformational history of the Transvaal Supergroup in southern Botswana. The ca. 235 Ma kimberlite diatremes intruded into late Archaean to Early Proterozoic, mixed, siliciclastic-carbonate sediments, that were subjected to at least three deformational events. The first deformational event (D1), caused by NW-SE directed compression, is responsible for NE-trending, open folds (F1) with associated diverging, fanning, axial planar cleavage. The second deformational event (D2) is probably progressive, involving a clockwise rotation of the principal stress to NE-SW trends. Early D2, which was N-S directed, involved left-lateral, oblique shearing along cleavage planes that developed around F1 folds, along with the development of antithetic structures. Progressive clockwise rotation of far-field forces saw the development of NW-trending folds (F2) and its associated, weak, axial planar cleavage. D3 is an extensional event in which normal faulting, along pre-existing cleavage planes, created a series of rhomboid-shaped, fault-bounded blocks. Normal faults, which bound these blocks, are the dominant structures at Jwaneng Mine. Combined with block rotation and NW-dipping bedding, a horst-like structure on the northwestern limb of a broad, gentle, NE-trending anticline is indicated. The early compressional and subsequent extensional events are consistent throughout the Jwaneng-Ramotswa-Lobatse-Thabazimbi area, suggesting that a large area records the same fault geometry and, consequently, deformational history. It is proposed that Jwaneng Mine is at or near the northernmost limit of the initial, northwards-directed compressional event.
DS201811-2563
2018
Ramsden, F.Creus, P.K., Basson, I.J., Stoch, B., Mogorosi, O., Gabanakgosi, K., Ramsden, F., Gaegopolwe, P.Structural analysis and implicit 3D modelling of Jwaneng mine: insights into deformation of the Transvaal Supergroup in SE Botswana.Journal of African Earth Sciences, Vol. 137, pp. 9-21.Africa, Botswanadeposit - Jwaneng

Abstract: Country rock at Jwaneng Diamond Mine provides a rare insight into the deformational history of the Transvaal Supergroup in southern Botswana. The ca. 235 Ma kimberlite diatremes intruded into late Archaean to Early Proterozoic, mixed, siliciclastic-carbonate sediments, that were subjected to at least three deformational events. The first deformational event (D1), caused by NW-SE directed compression, is responsible for NE-trending, open folds (F1) with associated diverging, fanning, axial planar cleavage. The second deformational event (D2) is probably progressive, involving a clockwise rotation of the principal stress to NE-SW trends. Early D2, which was N-S directed, involved left-lateral, oblique shearing along cleavage planes that developed around F1 folds, along with the development of antithetic structures. Progressive clockwise rotation of far-field forces saw the development of NW-trending folds (F2) and its associated, weak, axial planar cleavage. D3 is an extensional event in which normal faulting, along pre-existing cleavage planes, created a series of rhomboid-shaped, fault-bounded blocks. Normal faults, which bound these blocks, are the dominant structures at Jwaneng Mine. Combined with block rotation and NW-dipping bedding, a horst-like structure on the northwestern limb of a broad, gentle, NE-trending anticline is indicated. The early compressional and subsequent extensional events are consistent throughout the Jwaneng-Ramotswa-Lobatse-Thabazimbi area, suggesting that a large area records the same fault geometry and, consequently, deformational history. It is proposed that Jwaneng Mine is at or near the northernmost limit of the initial, northwards-directed compressional event.
DS1990-1213
1990
Ramsey, F.P.Ramsey, F.P.Weight or the value of knowledgeBritish Journal of for the Philosphy of Science, Vol. 41, No. 1, March pp. 1-4GlobalInformation, Value
DS201012-0610
2010
Ramsey, M.H.Ramsey, M.H., Boon, K.A.New approach to geochemical measurement: estimation of measurement uncertainty from sampling, rather than an assumption of representative.Geostandards and Geoanaltyical Research, Vol. 34, 3, pp. 293-304.TechnologySampling - not specific to diamonds
DS200512-0533
2004
Ramsey, M.S.King, P.L., Ramsey, M.S., Swayze, G.A.Infrared spectroscopy in geochemistry, exploration geochemistry and remote sensing.Mineralogical Association of Canada, SC33, 284p. $ 40.Book - infrared spectroscopy not specific to diamonds
DS201412-0752
2014
Ramsey, M.S.Rooney, T.O., Bastow, I.D., Keir, D., Mazzarini, F., Movsesian, E., Grosfils, E.B., Zimbelman, J.R., Ramsey, M.S., Ayalew, D., Yirgu, G.The protracted development of focused magmatic intrusion during continental rifting.Tectonics, Vol. 33, 6, pp. 875-897.Africa, EthiopiaPrecambrian lineaments
DS1991-1609
1991
Ramsey, R.R.Smith, C.B., Lucas, H., Hall, A.E., Ramsey, R.R.Diamond prospectivity from indicator mineralogy: a western AustralianperspectiveProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 380-382AustraliaHeavy mineral sampling, Hadfields, Pteropus, Argyle, Ellendale, peridotite, harzburgite, lherzolite, Skerring
DS1989-0794
1989
Ramshorn, Ch.Klein, H., Pflug, R., Ramshorn, Ch.Shaded perspective views by computer: a new tool for geologistsGeobyte, August pp. 16, 18-24. Database # 18148GlobalComputer, Program - perspective views
DS200512-0243
2004
Ramstein, G.Donnadieu, Y., Ramstein, G., Godderis, Y., Fluteau, F.Global tectonic setting and climate of the Late Neoproterozoic: a climate geochemical coupled study.American Geophysical Union, Geophysical Monograph, No. 146, pp. 79-90.Geomorphology - tectonics
DS200812-0638
2008
Ramstein, G.Le Hir, G., Ramstein, G., Donnadieu, Y., Godderis, Y.Scenario for the evolution of atmospheric pCO2 during a snowball Earth.Geology, Vol. 36, 1, pp. 47-50.MantleCarbon cycle
DS202001-0034
2019
Ramstein, G.Ramstein, G., Godderis, Y., Donnadieu, Y., Sepulchre, P., Fluteau, F., Zhang, Z., Zhang, R., Su, B., Jiang, D., Schuster, M., Besse, J.Some illustrations of large tectonically driven climate changes in Earth history.Tectonics, doi.org/10.1029/ 2019TC005569Mantletectonics

Abstract: For the celebration of the 50th anniversary of the publication of the pioneering papers that established the basis of plate tectonic, this paper was solicited to illustrate the close relation between tectonics and climate. Amongst the large spectrum of interactions that depict how tectonics modified the climate at geological time steps, we choose to illustrate two major issues: (1) How the “tryptic” climate/long?term carbon cycle/tectonics explains the extraordinary glacial episode (717-635 Ma) occurring during Neoproterozoic era? (2) How major tectonic events (i.e., the slow shrinkage of a huge epicontinental sea and the uplift of large mountains ranges in Asia and Africa) drastically changed the climate and shaped the pattern of present?day monsoons systems. This paper is the result of long?standing collaboration with many researchers from different countries.
DS202009-1620
2020
Rana, S.Choudhary, S., Sen, K., Kumar, S., Rana, S., Ghosh, S.Forsterite repricipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic-alkaline-carbonatite complex, Meghalaya, NE India.Geological Magazine, 10.1017/S001675 68200000631 12p.Indiacarbonatites

Abstract: Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2-H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2-H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution-precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2-H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.
DS202101-0003
2020
Rana, S.Choudhary, S., Sen, K., Kumar, S., Rana, S., Ghosh, S.Forsterite reprecipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic-alkaline-carbonatite complex, Meghalaya, NE India.Geological Magazine, doi:1017/S001 6756820000631, 12p.Indiadeposit - Sung Valley

Abstract: Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2-H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2-H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution-precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2-H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.
DS202103-0372
2021
Rana, S.Choudhary, S., Sen, K., Kumar, S., Rana, S., Ghosh, S.Forsterite reprecipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic-alkaline-carbonatite complex, Meghalaya, NE India.Geological Magazine, Vol. 158, 3, pp. 475-486.Indiadeposit - Sung Valley

Abstract: Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2-H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2-H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution-precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2-H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.
DS200512-0006
2005
Ranali, G.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
DS1997-0345
1997
Ranalli, G.Fernandez, M., Ranalli, G.The role of rheology in extensional basin formation modellingTectonophysics, Vol. 282, No. 1-4, Dec. 15, pp. 129=146GlobalBasin, Tectonics - extensional
DS1997-0945
1997
Ranalli, G.Ranalli, G.Rheology of the lithosphere in time and spaceGeological Society of London, Orogeny through Time, No. 121, pp. 19-37.Alberta, Western CanadaTectonics - deformation, Lithosphere
DS2001-0964
2001
Ranalli, G.Ranalli, G.Experimental tectonics: from Sir James Hall to the presentJournal of Geodynamics, Vol. 32, No. 1-2, pp. 65=76.GlobalTectonics - experimental, History
DS2001-0965
2001
Ranalli, G.Ranalli, G.Mantle rheology: radial and lateral viscosity variations inferred from microphysical creep laws.Journal of Geodynamics, Vol. 32, No. 4-5, pp. 425-44.MantleTectonics, rheology, Geophysics - power law creep
DS2001-0966
2001
Ranalli, G.Ranalli, G.Mantle rheology: radial and lateral viscosity variations inferred from microphysical creep laws.Journal of Geodynamics, Vol. 32, No. 4-5, pp. 425-44.MantleBlank
DS2003-1127
2003
Ranalli, G.Ranalli, G.How soft is the crust?Tectonophysics, Vol. 361, 3-4, pp. 319-20.MantlePetrology
DS200512-0010
2004
Ranalli, G.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
DS200712-0869
2007
Ranalli, G.Ranalli, G., Piccardo, G.B., Corona Chavez, P.Softening of the continental lithsopheric mantle by asthenospheric melts and the continental extension /oceanic spreading transition.Journal of Geodynamics, Vol. 43, 4-5, pp. 450-464.MantleMelting
DS200812-0017
2008
Ranalli, G.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
DS201012-0003
2010
Ranalli, G.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
Ranalli, G.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
DS1989-0933
1989
Rancan, J.P.Marcelot, G., Dupuy, C., Dostal, J., Rancan, J.P., Pouclet, A.Geochemistry of mafic volcanic rocks from the Lake Kivu (Zaire and Rwanda)section of the western branch Of the African riftJournal of Volcanology and Geothermal Research, Vol. 39, No. 1, October pp. 73-88Democratic Republic of CongoTectonics, Rifting
DS2003-1128
2003
Rancic, D.Rancic, D., Djordjevikajan, S.MapEdit: solution to continuous raster map creationComputers and Geosciences, Vol. 29, 2, pp. 115-122.GlobalComputer - program
DS200412-1619
2003
Rancic, D.Rancic, D., Djordjevikajan, S.MapEdit: solution to continuous raster map creation.Computers & Geosciences, Vol. 29, 2, pp. 115-122.TechnologyComputer - program
DS1994-0973
1994
Rancourt, D.G.Lalonde, A.E., Rancourt, D.G., Chao, G.Y.iron bearing trioctahedral micas from Mont Saint Hilaire, QuebecGeological Association of Canada (GAC) Abstract Volume, Vol. 19, p.QuebecMineralogy, Mont Saint Hilaire
DS1996-0802
1996
Rancourt, D.G.Lalonde, A.E., Rancourt, D.G., Chao, G.Y.iron bearing trioctahedral micas from Mont Saint Hilaire Quebec, CanadaMineralogical Magazine, Vol. 60, pp. 447-460.QuebecAlkaline rocks, Deposit -Mont St. Hilaire region
DS1985-0554
1985
Rand, S.C.Rand, S.C., Deshazer, L.G.Visible Color Centre Laser in DiamondOptics Letters, Vol. 10, No. 10, October pp. 481-483GlobalSpectroscopy, Diamond Morphology
DS1960-0086
1960
Randall, B.A.O.Randall, B.A.O.Sagvandites of Lyngen, Troms, North NorwayInternational Geological Congress 21ST., REPORT No. 13, PP. 443-451.Norway, ScandinaviaPetrology
DS202202-0190
2022
Randive, K.Dora, M.L., Randive, K., Meshram, R., Meshram, T., Baswani, S.R., Korakoppa, M., Malviya, V.P.Petrogenesis of a calc-alkaline lamprophyre ( minette) from Thanewasna western Bastar craton, central India: insights from mineral, bulk rock and in-situ trace element geochemistry.Geological Society of London Special Publication 513, pp. 179-207.Indiaminette

Abstract: The lamproites and kimberlites are well known from the Eastern Bastar Craton, Central India. However, a Proterozoic lamprophyre dyke is discussed here, from the Western Bastar Craton (WBC). The field geology, petrographic, mineralogical and whole-rock and in-situ trace element geochemistry of biotite are described to understand the petrogenesis and lithospheric evolution in the WBC. The Thanewasna lamprophyre (TL) is undeformed and unmetamorphosed, intruded into c. 2.5 Ga charnockite and metagabbro but closely associated with c. 1.62 Ga undeformed Mul granite. The TL has a characteristic porphyritic texture, dominated by phenocrysts of biotite, microphenocryst of amphibole, clinopyroxene and a groundmass controlled by feldspar. Mineral chemistry of biotite and amphibole suggest a calc-alkaline (CAL) type, and pyroxene chemistry reveals an orogenic setting. The TL is characterized by high SiO2 and low TiO2, MgO, Ni and Cr, consistent with its subcontinental lithospheric origin. The presence of crustal xenolith and ocelli texture followed by observed variations in Th/Yb, Hf/Sm, La/Nb, Ta/La, Nb/Yb, Ba/Nb indicate substantial crustal contamination. Whole-rock and in-situ biotite analysis by laser ablation inductively coupled plasma mass spectrometry show low concentrations of Ni (30-50 ppm) and Cr (70-150 ppm), pointing to the parental magma evolved nature. Enrichment in H2O, reflected in magmatic mica dominance, combined with high large ion lithophile element, Th/Yb ratios, and striking negative Nb-Ta anomalies in trace element patterns, is consistent with a source that was metasomatized by hydrous fluids corresponding to those generated by subduction-related processes. Significant Zr-Hf and Ti anomalies in the primitive mantle normalized multi-element plots and the rare earth element pattern of the TL, similar to the global CAL average trend, including Eastern Dharwar Craton lamprophyres. Our findings provide substantial petrological and geochemical constraints on petrogenesis and geodynamics. However, the geodynamic trigger that generated CAL magmatism and its role in Cu-Au metallogeny in the WBC, Central India, is presently indistinct in the absence of isotopic studies. Nevertheless, the lamprophyre dyke is emplaced close to the Cu-(Au) deposit at Thanewasna.
DS1997-0944
1997
Randive, K.R.Ramasamy, R., Gwalani, L.G., Randive, K.R., Mulai, B.P.Geology of the Indian carbonatites and evolution of alkali carbonatite magma in peninsular India.Geological Association of Canada (GAC) Abstracts, POSTER.IndiaCarbonatite
DS200812-0933
2008
Randive, K.R.Randive, K.R.Compositional variation of micas from the lamprophyre dykes of Bakhatgarh Phulmal area, Jhabua District, M P. India.Indian Dykes: editors Srivastava, Sivaji, Chalapathi Rao, pp. 133-141.India, Madhya PradeshLamprophyre, mineralogy
DS201112-0842
2011
Randive, K.R.Randive, K.R.Occurrence of xenoliths in the lamprophyre and picrobasalt dykes of Bakhatgarh Phulmal area, Jhabula district, Madhya Pradesh, India.In: Dyke swarms: keys to geodynamic interpretation, Part 1, pp. 301-313.IndiaLamprophyre
DS201801-0052
2017
Randive, K.R.Randive, K.R.Primary carbonate-silicate association in the pelletal lapilli: first direct evidence of carbonated peridotitic mantle source for Amba Dongar carbonatites, Deccan igneous province, India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 30.Indiadeposit - Amba Dongar

Abstract: Pelletal lapilli are discrete sub-spherical clasts with a central fragment mantled by a rim of probable juvenile origin. They typically range in size from <1 mm – 60 mm, and occur as accessory components of pipe-filling volcaniclastic rocks such as kimberlites, carbonatites, kamafugites, melilitites and orangeites. They have been variously referred to as ‘tuffacitic lapilli’, ‘spherical or elliptical lapilli’, ‘Pele’s tears’, ‘spinning droplets’, ‘cored lapilli’, or ‘concentric shelled lapilli. Their presence has been increasing reported from extrusive carbonatite complexes world over; for e.g. Umbria and Latium, Central Italy, Abruzzo and Lucaniae, Southern Italy; Fort Portal and Katwe Kikorongo, Uganda; West Qinling, China; Campo de Calatrava, Spain, along with others. I am reporting here occurrence of pelletal and cored lapilli in the proximity of Amba Dongar carbonatite complex. The lapillus comprises of abundant phenocrysts of olivine, which are typically rimmed by dark brown thick coating. Such phenocrysts (oikocrysts) acquire remarkable roundedness, many of these show central circular fracture. Some of the phenocrysts are broken yet preserving their thick-brown rim. This feature is accentuated where such olivine oikocrysts are welded over groundmass mafics (typically clinorpyroxenes). However, most conspicuous thing is the presence of chrome spinel, which is dispersed as minor octahedra within the olivine, but not found in association with other minerals implying that olivine and chrome spinels are primary phases within the lapilli. There are other smaller droplets forming cored lapilli, which are dominantly composed of carbonates. Mineral chemistry of different phases indicate presence of forsteric (Fo89.20-67.34: Fa32.10-10.71: Tp0.46-0.04); chromium-rich spinel (Chromite55.34-24.86, Spinel31.88-10.16, Magnetite34.13-8.68, Mag. Chromite24.45-0.00, Ulvospinel23.21-0.00, Mag. Ulvospinel7.00-0.00, diopsidic clinopyroxene (Wo45.36-41.41: En40.92-50.60: Fs7.98-15.46), ilmenite (Il76.79-75.10:Ge13.08-14.60:Py1.72-1.08:He9.22-7.26), calcic-plagioclase (An69.36-47.90:Ab48.32- 29.27:Or3.78-1.37), and chlorite (ripidolite/brunsvigite). Discovery of pelletal and cored lapilli in the proximity of Amba Dongar carbonatite complex thus provide first direct evidence of the carbonated peridotitic mantle source for Amba Dongar carbonatites.
DS202007-1163
2019
Randive, K.R.Meshram, R.R., Dora, M.L., Naik, R., Shareef, M., Gopalakrishna, G., Moeshram, T., Baswani, S.R., Randive, K.R.A new find of calc-alkaline lamprophyres in Thanewasna area, western Bastar craton, India.Journal of Earth System Science, Vol. 128, 1, 7p. PdfIndiaminette

Abstract: Lamprophyre dykes within the granitoid and charnockite are reported for the first time from the Western Bastar Craton, Chandrapur district, Maharashtra. It shows porphyritic-panidiomorphic texture under a microscope, characterised by the predominance of biotite phenocrysts with less abundance of amphibole and clinopyroxene microphenocryst. The groundmass is composed more of K-feldspars over plagioclase, amphiboles, clinopyroxene, biotite, chlorite, apatite, sphene and magnetite. The mineral chemistry of biotite and magnesio-hornblende is indicative of minette variety of calc-alkaline lamprophyre (CAL), which is further supported by preliminary major oxides and trace element geochemistry. This unique association of CAL with granitoid provides an opportunity to study the spatio-temporal evolution of the lamprophyric magma in relation to the geodynamic perspective of the Bastar Craton.
DS202103-0413
2021
Randriamanjakahasina, O.Stoudmann, N., Reibelt, L.M., Rakotomalala, A.G., Randriamanjakahasina, O., Garcia, C.A., Waeber, P.O.A double edged sword: realities of artisanal and small scale mining for rural people in the Alaotra region of Madagascar. ** not specific to diamondsNatural Resources Forum, Vol 45 pp. 87-102. pdfAfrica, Madagascaralluvials

Abstract: A growing number of people are entering the artisanal and small?scale mining (ASM) sector worldwide. In Madagascar, millions of individuals depend on this informal activity. Through a case study in the Alaotra?Mangoro region of Madagascar, our research aimed to understand the "bottom?up" dynamics and ripple effects of the sector, by looking at the realities for rural communities where inhabitants are both directly and indirectly affected by ASM. We were interested in community members' and miners' perceptions of the socio?economic and environmental impacts of ASM, and in identifying the factors attracting people living in one of the country's agricultural hubs to this activity. Our results show a wide diversity of push and pull factors leading people to enter the sector. Although many positive impacts of ASM exist for miners and communities within the vicinity of mines, most miner participants considered themselves worse off since starting to mine, highlighting the high risk and low probability of return of ASM. ASM's potential for local and national development will remain squandered if its negative impacts continue to go unmanaged. Accounting for local contexts and the ripple effects of ASM will be crucial in achieving safety and security for miners, and to tap into the benefits it may offer communities while minimising environmental damage.
DS201412-0553
2014
Randrianandraisana, A.Martin, R.F., Randrianandraisana, A., Boulvais, P.Ampandrandava and similar phlogopite deposits in southern Madagascar: derivation from a silicocarbonatitic melt of crustal origin.Journal of African Earth Sciences, Vol. 94, pp. 111-118.Africa, MadagascarCarbonatite
DS2002-1759
2002
Ranero, C.Yanez, G., Cembrano, J., Pardo, M., Ranero, C., SellesThe Challinger Juan Fernadex Maipo major tectonic transition of the Nazca Andean subduction system 33-34Journal of South American Earth Sciences, Vol.15,1,Apr.pp.23-38.Chile, AndesSubduction, Geodynamic evidence and implications
DS200412-1543
2004
Ranero, C.R.Phipps Morgan, J., Reston, T.J., Ranero, C.R.Contemporaneous mass extinctions, continental flood basalts, and impact signals are mantle plume induced lithospheric gas explosEarth and Planetary Science Letters, Vol. 217, 3, Jan. 15, pp. 263-284.MantlePlume
DS2001-0568
2001
RanganaiKampunzu, A.B., Atekwana, McCourt, Tombale, RanganaiInteraction between Kaapvaal and Zimbabwe Cratons during the Neoarchean and implications for transition..Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractSouth Africa, ZimbabweArchean and post Archean plate tectonic styles, Limpopo Shashe belt
DS2000-0040
2000
Ranganai, R.T.Atekwana, E.A., Ranganai, R.T.Gravity and magnetic anomaly maps of the Limpopo Belt in southern Africa: implications for evolution KaapvaalGeological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-376.South Africa, ZimbabweGeophysics - gravity, magnetics, Craton - Kaapvaal, Zimbabwe
DS2000-0041
2000
Ranganai, R.T.Atekwana, E.A., Ranganai, R.T.Gravity and magnetic anomlay maps of the Limpopo Belt in southern Africa: implications for evolution KaapvaalGeological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-376.South Africa, ZimbabweGeophysics - gravity, magnetics, Craton - Kaapvaal, Zimbabwe
DS200812-0934
2008
Ranganai, R.T.Ranganai, R.T., Ebinger, C.J.Aeromagnetic and Land sat TM structural interpretation for identifying regional groundwater exploration targets, south central Zimbabwean Craton.Journal of Applied Geophysics, Vol. 65, 2, pp. 73-83.Africa, ZimbabweGeophysics
DS200812-0935
2008
Ranganai, R.T.Ranganai, R.T., Whaler, K.A., Ebinger, C.J.Gravity anomaly patterns in the south central Zimbabwe Archean Craton and their geological interpretation.Journal of African Earth Sciences, Vol. 51, 5, pp. 257-276.Africa, ZimbabweGeophysics - gravity
DS201602-0233
2016
Ranganai, R.T.Ranganai, R.T., Whaler, K.A., Ebinger, C.J.Aeromagnetic interpretation in the south-central Zimbabwe craton: (reappraisal of) crustal structure and tectonic implications.International Journal of Earth Sciences, in press available, 27p.Africa, ZimbabweGeophysics - magnetics

Abstract: Regional aeromagnetic data from the south-central Zimbabwe Craton have been digitally processed and enhanced for geological and structural mapping and tectonic interpretation integrated with gravity data, to constrain previous interpretations based on tentative geologic maps and provide new information to link these structural features to known tectonic events. The derived maps show excellent correlation between magnetic anomalies and the known geology, and extend lithological and structural mapping to the shallow/near subsurface. In particular, they reveal the presence of discrete crustal domains and several previously unrecognised dykes, faults, and ultramafic intrusions, as well as extensions to others. Five regional structural directions (ENE, NNE, NNW, NW, and WNW) are identified and associated with trends of geological units and cross-cutting structures. The magnetic lineament patterns cut across the >2.7 Ga greenstone belts, which are shown by gravity data to be restricted to the uppermost 10 km of the crust. Therefore, the greenstone belts were an integral part of the lithosphere before much of the upper crustal (brittle) deformation occurred. Significantly, the observed magnetic trends have representatives craton-wide, implying that our interpretation and inferences can be applied to the rest of the craton with confidence. Geological-tectonic correlation suggests that the interpreted regional trends are mainly 2.5 Ga (Great Dyke age) and younger, and relate to tectonic events including the reactivation of the Limpopo Belt at 2.0 Ga and the major regional igneous/dyking events at 1.8-2.0 Ga (Mashonaland), 1.1 Ga (Umkondo), and 180 Ma (Karoo). Thus, their origin is here inferred to be inter- and intra-cratonic collisions and block movements involving the Zimbabwe and Kaapvaal Cratons and the Limpopo Belt, and later lithospheric heating and extension associated with the break-up of Gondwana. The movements produced structures, or reactivated older fractures, that were exploited by Late Archaean and Proterozoic mafic intrusions. There was interplay between vertical and horizontal tectonics as seen in similar terrains worldwide.
DS201611-2134
2016
Ranganai, R.T.Ranganai, R.T., Whaler, K.A., Ebinger, C.J.Aeromagnetic interpretation in the south central Zimbabwe Craton: ( reappraisal of) crustal structure and tectonic implications.International Journal of Earth Sciences, Vol. 105, 8, pp. 2175-2201.Africa, ZimbabweGeophysics - gravity

Abstract: Regional aeromagnetic data from the south-central Zimbabwe Craton have been digitally processed and enhanced for geological and structural mapping and tectonic interpretation integrated with gravity data, to constrain previous interpretations based on tentative geologic maps and provide new information to link these structural features to known tectonic events. The derived maps show excellent correlation between magnetic anomalies and the known geology, and extend lithological and structural mapping to the shallow/near subsurface. In particular, they reveal the presence of discrete crustal domains and several previously unrecognised dykes, faults, and ultramafic intrusions, as well as extensions to others. Five regional structural directions (ENE, NNE, NNW, NW, and WNW) are identified and associated with trends of geological units and cross-cutting structures. The magnetic lineament patterns cut across the >2.7 Ga greenstone belts, which are shown by gravity data to be restricted to the uppermost 10 km of the crust. Therefore, the greenstone belts were an integral part of the lithosphere before much of the upper crustal (brittle) deformation occurred. Significantly, the observed magnetic trends have representatives craton-wide, implying that our interpretation and inferences can be applied to the rest of the craton with confidence. Geological-tectonic correlation suggests that the interpreted regional trends are mainly 2.5 Ga (Great Dyke age) and younger, and relate to tectonic events including the reactivation of the Limpopo Belt at 2.0 Ga and the major regional igneous/dyking events at 1.8-2.0 Ga (Mashonaland), 1.1 Ga (Umkondo), and 180 Ma (Karoo). Thus, their origin is here inferred to be inter- and intra-cratonic collisions and block movements involving the Zimbabwe and Kaapvaal Cratons and the Limpopo Belt, and later lithospheric heating and extension associated with the break-up of Gondwana. The movements produced structures, or reactivated older fractures, that were exploited by Late Archaean and Proterozoic mafic intrusions. There was interplay between vertical and horizontal tectonics as seen in similar terrains worldwide.
DS201612-2328
2016
Ranganai, R.T.Ranganai, R.T., Whaler, K.A., Ebinger, C.J.Aeromagnetic interpretation in the south central Zimbabwean Craton: (reappraisal of) crustal structure and tectonic implications.International Journal of Earth Sciences, Vol. 105, 8, pp. 2175-2201.Africa, ZimbabweGeophysics - magnetics

Abstract: Regional aeromagnetic data from the south-central Zimbabwe Craton have been digitally processed and enhanced for geological and structural mapping and tectonic interpretation integrated with gravity data, to constrain previous interpretations based on tentative geologic maps and provide new information to link these structural features to known tectonic events. The derived maps show excellent correlation between magnetic anomalies and the known geology, and extend lithological and structural mapping to the shallow/near subsurface. In particular, they reveal the presence of discrete crustal domains and several previously unrecognised dykes, faults, and ultramafic intrusions, as well as extensions to others. Five regional structural directions (ENE, NNE, NNW, NW, and WNW) are identified and associated with trends of geological units and cross-cutting structures. The magnetic lineament patterns cut across the >2.7 Ga greenstone belts, which are shown by gravity data to be restricted to the uppermost 10 km of the crust. Therefore, the greenstone belts were an integral part of the lithosphere before much of the upper crustal (brittle) deformation occurred. Significantly, the observed magnetic trends have representatives craton-wide, implying that our interpretation and inferences can be applied to the rest of the craton with confidence. Geological-tectonic correlation suggests that the interpreted regional trends are mainly 2.5 Ga (Great Dyke age) and younger, and relate to tectonic events including the reactivation of the Limpopo Belt at 2.0 Ga and the major regional igneous/dyking events at 1.8-2.0 Ga (Mashonaland), 1.1 Ga (Umkondo), and 180 Ma (Karoo). Thus, their origin is here inferred to be inter- and intra-cratonic collisions and block movements involving the Zimbabwe and Kaapvaal Cratons and the Limpopo Belt, and later lithospheric heating and extension associated with the break-up of Gondwana. The movements produced structures, or reactivated older fractures, that were exploited by Late Archaean and Proterozoic mafic intrusions. There was interplay between vertical and horizontal tectonics as seen in similar terrains worldwide.
DS201801-0062
2017
Rangarajan, G.Shitole, A., Sant, D.A., Parvez, I.A., Rangarajan, G., Patel, S., Viladkar, S.G., Murty, A.S.N., Kumari, G.Shallow seismic studies along Amba Dongar to Sinhada ( longitude 74 3 50E) transect, western India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 16.Indiadeposit - Amba Dongar

Abstract: The microtremor method is applied to map subsurface rheological boundaries (stratigraphic, faults and plutons) is based on strong acoustic impedance across contrasting density of rock/ sediment/ weathered interfaces up to shallow depths along longitude 74° 3'50" E from village Amba Dongar (latitude: 21° 59'N) up to Sinhada village (latitude: 22° 14' N). The 30 km long transect exposes variety of rocks viz., unclassified granite gneisses and metasediments (Precambrian age); sediments belonging to Bagh Group (Late Cretaceous); alkaline - carbonatite plutons and lava flows belonging to Deccan Traps (Late Cretaceous). In all, sixty stations were surveyed along the longitude 74° 3'50" E with spacing of 500 m. H/V spectral ratio technique reveals four rheological interfaces identified by resonant frequencies (fr) ranges 0.2213 to 0.7456 Hz (L1), 1.0102 to 3.076 Hz (L2), 4.8508 to 21.0502 Hz (L3), and 24.5018 to 27.1119 Hz (L4). L1 represents interface between plutons, Precambrian basement rocks; L2 represents interface between Bagh sediments, Deccan Traps and intrusives whereas L3 and L4 captures depth of top most weathered profile. We estimate the depth range for L1 L2 L3 and L4 using equation (h = 110.18fr?1.97) derived based on Deep Banni Core (1764 m deep from surface: DGH record). Deep Banni Core has a distinct interface between Mesozoic rocks and Precambrian basement. The depths are further compared with terrain-based equation. Further, the overall results from the present study are compared with seismic refraction studies along Phangia-Kadipani (NGRI Technical Report, 2003). The subsurface profile across longitude 74° 3'50" E educe faults that bound Bagh Group of rocks with Deccan Trap and Precambrian. We identify two plutons underneath three zones of intrusive viz., Amba Dongar Carbonatite Complex (Station 1 to 8), Tiloda Alkaline (station 33 to 44) and Rumadia Alkaline (station 46 to 51). The present study demarcates the presence of depression over Amba Dongar hill (station 1 to 3), filled by post carbonatite basalt earlier reported by Viladkar et al., (1996 and 2005) suggesting caldera morphology. Similarly, studies identify intrusive-pluton interfaces one, below the Amba Dongar hill, and second between village Tiloda and Rumadia at depth of ~500 m from the surface. Microtremor survey further depicts both basement morphology and thickness of Bagh Group and Deccan Traps.
DS1900-0698
1908
Range, P.Range, P.Dwykakonglomerat in Deutsch Suedwest AfrikaZeitschr. Deut. Geol. Ges., Vol. 60, No. 3, PP. 64-66.Southwest Africa, NamibiaGeology
DS1900-0794
1909
Range, P.Range, P.Die Diamant felder Bei LuderitzbuchtDeut. Kolonialblatt., Vol. 20, No. 22, PP. 1039-1048; MAP 1: 800, 000.Southwest Africa, NamibiaGeology, Marine Diamond Placers
DS1900-0795
1909
Range, P.Range, P.Die Geologischen Formationen des NamalandesMon. Ber.. Deutsch. Geol. Ges. Berlin., Vol. 61, PT. 2, PP. 120-130.Southwest Africa, NamibiaStratigraphy, Brukkaros
DS1910-0086
1910
Range, P.Range, P.Zur Geologie des NamalandesMonatsb. Deutsch. Geol. Ges. Berlin., PP. 462-468.Southwest Africa, NamibiaGeology
DS1910-0087
1910
Range, P.Range, P.Sketch of the Geology of German NamaqualandGeological Society of South Africa Transactions, Vol. 13, PP. 1-9.Southwest Africa, NamibiaRegional Geology, Brukkaros
DS1910-0088
1910
Range, P.Range, P.Diamant vorkommen in den Vereinigten Staetten von AmerikaDeut. Kolonialblatt., Vol. 21, PP. 942-943.United States, Gulf Coast, ArkansasDiamond Occurrence
DS1910-0207
1911
Range, P.Range, P.Das LuederitzlandMitt. Deutsch. Schutzgeb., Vol. 24, No. 1, PP. 30-42.Southwest Africa, NamibiaGeology
DS1910-0302
1912
Range, P.Range, P.Geologie des Deutschen NamalandesBeitr. Geol. Erf. Deut. Schutzgeb., Vol. 2, 104P.; MAP 1:2, 000, 000.Southwest Africa, NamibiaRegional, Geology, Kimberley, Janlib
DS1910-0372
1913
Range, P.Range, P.Meteoriten aus Deutsch SuedwestafrikaMitt. Deutsch. Schutzgeb., Vol. 26, No. 4, PP. 341-343.Southwest Africa, NamibiaMeteorite
DS1910-0471
1915
Range, P.Range, P.Geitsi Gubib, an Old VolcanoRoyal Society. STH. AFR. Transactions, Vol. 5, PP. 247-257.Southwest Africa, NamibiaDiamond, Kimberlite, Carbonatite, Geomorphology
DS1920-0169
1923
Range, P.Range, P.Die Diamant vorkommen der ErdeZeitschr. F. Prakt. Geol., Vol. 31, PP. 49-55; P. 65.South Africa, Global, Southwest Africa, NamibiaDiamond Occurrences
DS1920-0294
1926
Range, P.Range, P.Die Diamant lagerstatten AfrikasKol. Rundschau (berlin), Vol. 18, No. 1, PP. 17-19.South Africa, West Africa, East Africa, Southwest Africa, NamibiaDiamond Occurrences
DS1920-0463
1929
Range, P.Range, P.Die Diamant vorkommen in Klein-namaqualandUebersee And Kolonial Zeitung, No. 8, P. 154.South Africa, Namaqualand CoastDiamond Occurrences
DS1920-0464
1929
Range, P.Range, P.Die Neuendeckten Diamantefelder in Klein NamaqualandSteinbr. Sandgr., Vol. 33, PP. 517-519.South Africa, Namaqualand CoastDiamond Occurrences
DS1930-0226
1936
Range, P.Range, P.Mineral funde und Bergbau in Den Deutschen Schutzgebieten In afrika und in der Suedsee.Kolon. Rundschau, Vol. 27, No. 3, PP. 196-209.Southwest Africa, NamibiaDiamond Occurrences
DS201708-1741
2017
Ranger, I.Ranger, I.Punctuated long lived emplacement history of kimberlites from the Renard cluster, Superior Province, Canada indicated by new high precision U-Pb groundmass perovskite dating.11th. International Kimberlite Conference, OralCanada, Quebecdeposit - Renard
DS201810-2370
2018
Ranger, I.M.Ranger, I.M., Heaman, L.M., Pearson, D.G., Muntener, C., Zhuk, V.Punctuated, long lived emplacement history of the Renard 2 kimberlite, Canada, revealed by new high precision U-Pb groundmass perovskite dating. IF-TIMSMineralogy and Petrology, doi.org/101007/ s00710-018-0629-0 13p.Canada, Quebecdeposit - Renard

Abstract: Kimberlites are rare volatile-rich ultramafic magmas thought to erupt in short periods of time (<1 Myr) but there is a growing body of evidence that the emplacement history of a kimberlite can be significantly more protracted. In this study we report a detailed geochronology investigation of a single kimberlite pipe from the Renard cluster in north-central Québec. Ten new high precision ID-TIMS (isotope dilution - thermal ionization mass spectrometry) U-Pb groundmass perovskite dates from the main pipe-infilling kimberlites and several small hypabyssal kimberlites from the Renard 2 pipe indicate kimberlite magmatism lasted at least ~20 Myr. Two samples of the main pipe-infilling kimberlites yield identical weighted mean 206Pb/238U perovskite dates with a composite date of 643.8?±?1.0 Myr, interpreted to be the best estimate for main pipe emplacement. In contrast, six hypabyssal kimberlite samples yielded a range of weighted mean 206Pb/238U perovskite dates between ~652-632 Myr. Multiple dates determined from these early-, syn- and late-stage small hypabyssal kimberlites in the Renard 2 pipe demonstrate this rock type (commonly used to date kimberlites) help to constrain the duration of kimberlite intrusion history within a pipe but do not necessarily reliably record the emplacement age of the main diatreme in the Renard cluster. Our results provide the first robust geochronological data on a single kimberlite that confirms the field relationships initially observed by Wagner (1914) and Clement (1982); the presence of antecedent (diatreme precursor) intrusions, contemporaneous (syn-diatreme) intrusions, and consequent (post-diatreme) cross-cutting intrusions. The results of this detailed U-Pb geochronology study indicate a single kimberlite pipe can record millions of years of magmatism, much longer than previously thought from the classical viewpoint of a rapid and short-duration emplacement history.
DS1994-0788
1994
Rangin, C.Huchon, P., Le Pichon, X., Rangin, C.Indochin a Peninsula and the collision of India and EurasiaGeology, Vol. 22, No. 1, January pp. 27-30China, IndiaTectonics, Deformation
DS1994-0789
1994
Rangin, C.Huchon, P., Le Pichon, X., Rangin, C.Indochin a Peninsula and the collision of India and EurasiaGeology, Vol. 22, No. 1, January pp. 27-30.China, IndiaTectonics, Deformation
DS202107-1101
2018
Rani, K.Guha, A., Rani, K., Varma, C.B., Sarwate, N.K., Sharma, N., Mukherjee, A., Kumar, K.V., Pal, S.K., Saw, A.K., Jha, S.K.Identification of potential zones for kimberlite exploration - an Earth observation approach. ChhatarpurThe International Achives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. XLII-5 12p. PdfIndia, Madhya PradeshASTER, lineament

Abstract: In the present study, we have prepared the thematic evidence layers for identifying the potential zones of kimberlite emplacement in parts of Chhatarpur district, Madhya Pradesh. These thematic layers or evidence layers are geological structure, alteration zones, lineament density, surface alteration and geomorphic anomaly and these layers are prepared from the remote sensing data. As orientation of the geological structures (i.e fault system) and their density have the major role in the emplacement of kimberlite; both of these evidence layers are integrated using "AND" Boolean Logical Operator. On the other hand, two evidential layers regarded as the proxy to indicate the "surface expressions on kimberlite (i.e. alteration zones and geomorphic anomaly) are combined using "OR" operator as either of these two surface expression is indicative of kimberlite. Consequently, conjugate evidence layers on the surface expressions of kimberlite are integrated with the causative evidence layers of kimberlite emplacement using "AND" operator to identify the potential zones of diamond occurrences. Potential zones of kimberlite are overlaid on the residual gravity anomaly map derived from space-based gravity model of European Improved Gravity of Earth by New Technique (EIGEN6C4) to relate potential zones of kimberlite with the similar structural alignment (delineated in the residual gravity map) of known occurrence of kimberlite. We also have carried out indicator mineral survey around these potential zones and some of the kimberlite specific indicator minerals are identified in the stream sediments within these potential zones.
DS2002-1306
2002
Raniengar, A.S.Raniengar, A.S.Carbonatite bodies of Dhanota Dkancholi area, Mahendragarh district HaryanaJournal of the Geological Society of India, Vol. 60, 5, Nov., pp. 587-92.IndiaBlank
DS200412-1620
2002
Raniengar, A.S.Raniengar, A.S.Carbonatite bodies of Dhanota Dkancholi area, Mahendragarh district Haryana.Journal of the Geological Society of India, Vol. 60, 5, Nov., pp. 587-92.IndiaCarbonatite
DS201012-0753
2010
Ranjan, P.Stanley, C.R., O'Driscoll, N., Ranjan, P.Determining the magnitude of true analytical error in geochemical analysis.Geochemistry: Exploration, Environment, Analysis, Vol. 10, 4, pp. 355-364.TechnologyGeochemistry - not specific to diamonds
DS201709-2067
2017
Ranjan, S.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
Ranjan, S.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.
DS201902-0264
2019
Ranjan, S.Chakraborty, T., Upadhyay, D., Ranjan, S., Pruseth, K.L., Nanda, J.K.The geological evolution of the Gangpur schist belt, eastern India: constraints on the formation of the greater Indian landmass of the Proterozoic.Journal of Metamorphic Geology, Vol. 37, 1, pp. 113-151.Indiageology

Abstract: The Central Indian Tectonic Zone (CITZ) is a Proterozoic suture along which the Northern and Southern Indian Blocks are inferred to have amalgamated forming the Greater Indian Landmass. In this study, we use the metamorphic and geochronological evolution of the Gangpur Schist Belt (GSB) and neighbouring crustal units to constrain crustal accretion processes associated with the amalgamation of the Northern and Southern Indian Blocks. The GSB sandwiched between the Bonai Granite pluton of the Singhbhum craton and granite gneisses of the Chhotanagpur Gneiss Complex (CGC) links the CITZ and the North Singhbhum Mobile Belt. New zircon age data constrain the emplacement of the Bonai Granite at 3,370 ± 10 Ma, while the magmatic protoliths of the Chhotanagpur gneisses were emplaced at c. 1.65 Ga. The sediments in the southern part of the Gangpur basin were derived from the Singhbhum craton, whereas those in the northern part were derived dominantly from the CGC. Sedimentation is estimated to have taken place between c. 1.65 and c. 1.45 Ga. The Upper Bonai/Darjing Group rocks of the basin underwent major metamorphic episodes at c. 1.56 and c. 1.45 Ga, while the Gangpur Group of rocks were metamorphosed at c. 1.45 and c. 0.97 Ga. Based on thermobarometric studies and zircon-monazite geochronology, we infer that the geological history of the GSB is similar to that of the North Singhbhum Mobile Belt with the Upper Bonai/Darjing and the Gangpur Groups being the westward extensions of the southern and northern domains of the North Singhbhum Mobile Belt respectively. We propose a three?stage model of crustal accretion across the Singhbhum craton - GSB/North Singhbhum Mobile Belt - GC contact. The magmatic protoliths of the Chhotanagpur Gneisses were emplaced at c. 1.65 Ga in an arc setting. The earliest accretion event at c. 1.56 Ga involved northward subduction and amalgamation of the Upper Bonai Group with the Singhbhum craton followed by accretion of the Gangpur Group with the Singhbhum craton-Upper Bonai Group composite at c. 1.45 Ga. Finally, continent-continent collision at c. 0.96 Ga led to the accretion of the CGC with the Singhbhum craton-Upper Bonai Group-Gangpur Group crustal units, synchronous with emplacement of pegmatitic granites. The geological events recorded in the GSB and other units of the CITZ only partially overlap with those in the Trans North China Orogen and the Capricorn Orogen of Western Australia, indicating that these suture zones are not correlatable.
DS202107-1092
2021
Rankenburg, K.Brennan, D.T., Li, Z-X., Rankenburg, K., Evans, N., Link, P.K.Recalibrating Rodinian rifting in the northwestern United States.Geology Today, Vol. 49, pp. 617-622.United States, Washingtongeochronology

Abstract: A lack of precise age constraints for Neoproterozoic strata in the northwestern United States (Washington State), including the Buffalo Hump Formation (BHF), has resulted in conflicting interpretations of Rodinia amalgamation and breakup processes. Previous detrital zircon (DZ) studies identified a youngest ca. 1.1 Ga DZ age population in the BHF, interpreted to reflect mostly first-cycle sourcing of unidentified but proximal magmatic rocks intruded during the amalgamation of Rodinia at ca. 1.0 Ga. Alternatively, the ca. 1.1 Ga DZ population has been suggested to represent a distal source with deposition occurring during the early phases of Rodinia rifting, more than 250 m.y. after zircon crystallization. We combined conventional laser-ablation split-stream analyses of U-Pb/Lu-Hf isotopes in zircon with a method of rapid (8 s per spot) U-Pb analysis to evaluate these opposing models. Our study of ?2000 DZ grains from the BHF identified for the first time a minor (?1%) yet significant ca. 760 Ma population, which constrains the maximum depositional age. This new geochronology implies that the BHF records early rift deposition during the breakup of Rodinia and correlates with sedimentary rocks found in other late Tonian basins of southwestern Laurentia.
DS201706-1076
2017
Rankey, E.C.Harmon, R.S., Hark, R.R., Throckmorton, C.S., Rankey, E.C., Wise, M.A., Somers, A.M., Collins, L.M.Geochemical fingerprinting by handheld laser-induced breakdown spectroscopy. (LIBS)Geostandards and Geoanalytical Research, in press availableTechnologyspectroscopy

Abstract: A broad suite of geological materials were studied a using a handheld laser-induced breakdown spectroscopy (LIBS) instrument. Because LIBS is simultaneously sensitive to all elements, the full broadband emission spectrum recorded from a single laser shot provides a ‘chemical fingerprint’ of any material - solid, liquid or gas. The distinguishing chemical characteristics of the samples analysed were identified through principal component analysis (PCA), which demonstrates how this technique for statistical analysis can be used to identify spectral differences between similar sample types based on minor and trace constituents. Partial least squares discriminant analysis (PLSDA) was used to distinguish and classify the materials, with excellent discrimination achieved for all sample types. This study illustrates through four selected examples involving carbonate minerals and rocks, the oxide mineral pair columbite-tantalite, the silicate mineral garnet and native gold how portable, handheld LIBS analysers can be used as a tool for real-time chemical analysis under simulated field conditions for element or mineral identification plus such applications as stratigraphic correlation, provenance determination and natural resources exploration.
DS1989-1253
1989
Rankin, A.H.Rankin, A.H.Fluid inclusions.An overview and layman's outline of what info they mayprovideGeology Today, Vol. 5, No. 1, Jan-Feb. pp. 21-24. Database # 17728GlobalFluid Inclusions, Ore genesis
DS1994-1781
1994
Rankin, A.H.Ting, W., Burke, E.A.J., Rankin, A.H., Woolley, A.R.The characterization and petrogenetic significance of CO2, H2O and CH4fluid inclusions in apatite SukuluEuropean Journal of Mineralogy, No. 6, pp. 787-804.UgandaCarbonatite, Deposit -Sukulu
DS1994-1782
1994
Rankin, A.H.Ting, W., Rankin, A.H., Woolley, A.R.Petrogenetic significance of solid carbonate inclusions in apatite of the Sukulu carbonatite, Uganda.Lithos, Vol. 31, No. 3-4, January pp. 177-188.UgandaCarbonatite, Apatite, Deposit -Sukulu
DS1996-1540
1996
Rankin, A.H.Wilkinson, J.J., Nolan, J., Rankin, A.H.Silicothermal fluid: a novel medium for mass transport in the lithosphereGeology, Vol. 24, No. 12, Dec. pp. 1059-62MantleFluid flow
DS1998-1181
1998
Rankin, A.H.Potter, J., Rankin, A.H., NI, P.A preliminary study of methane inclusions in alkaline igneous rocks of Kola igneous Province: implications...Eur. Journal of Mineralogy, Vol. 10, No. 6, Nov. 1, pp. 1167-80.Russia, Kola PeninsulaAlkaline rocks, Methane
DS1999-0099
1999
Rankin, A.H.Buhn, B., Rankin, A.H.Geochemistry and ore forming potential of alkali and volatile rich carbonatite magmas.Stanley, SGA Fifth Biennial Symposium, pp. 623-6.GlobalMagma, Carbonatite
DS1999-0564
1999
Rankin, A.H.Potter, J., Rankin, A.H., Treloar, P.J.The relationship between CH4 and CO2 inclusions and iron O S mineralization in intrusions Kola alkaline provinceStanley, SGA Fifth Biennial Symposium, pp. 87-90.Russia, Kola PeninsulaAlkaline rocks, Geochronology
DS2002-0218
2002
Rankin, A.H.Buhn, B., Rankin, A.H., Schneider, J., Dulski, P.The nature of orthomagmatic, carbonatitic fluids precipitating REE Sr rich flourite, fluid inclusion...Chemical Geology, Vol.186,1-2, pp. 75-98., Vol.186,1-2, pp. 75-98.NamibiaGeochronology - fluorite, Deposit - Okorusu
DS2002-0219
2002
Rankin, A.H.Buhn, B., Rankin, A.H., Schneider, J., Dulski, P.The nature of orthomagmatic, carbonatitic fluids precipitating REE Sr rich flourite, fluid inclusion...Chemical Geology, Vol.186,1-2, pp. 75-98., Vol.186,1-2, pp. 75-98.NamibiaGeochronology - fluorite, Deposit - Okorusu
DS200512-0868
2004
Rankin, A.H.Potter, J., Rankin, A.H., Treloar, P.J.Abiogenic Fischer-Topsch synthesis of hydrocarbons in alkaline igneous rocks: fluid inclusions, textural and isotopic evidence from the Lovozero complex, NW Russia.Lithos, Vol. 75, 3-4, pp. 311-358.RussiaAlkalic
DS200612-0114
2006
Rankin, A.H.Beeskow, B., Treloar, P.J., Rankin, A.H., Vennemann, T.W., Spangenberg, J.A reassessment of models for hydrocarbon generation in the Khibiny nepheline syenite complex, Kola Peninsula, Russia.Lithos, in press availableRussiaAlkalic
DS201012-0297
2010
Rankin, A.H.Humprhreys, E.R., Bailey, K., Hawkesworth, C.J., Wall, F., Najorka, J., Rankin, A.H.Aragonite in olivine from Calatrava, Spain - evidence for mantle carbonatite melts from > 100km depth.Geology, Vol. 38, 10, pp. 911-914.Europe, SpainCarbonatite
DS201802-0231
2017
Rankin, A.H.Dowman, E., Wall, F., Treloar, P.J., Rankin, A.H.Rare earth mobility as a result of multiple phases of fluid activity in fenite around the Chilwa Island carbonatite, Malawi.Mineralogical Magazine, Vol. 81, 6, pp. 1367-1395.Africa, Malawicarbonatite - Chilwa

Abstract: Carbonatites are enriched in critical raw materials such as the rare earth elements (REE), niobium, fluorspar and phosphate. A better understanding of their fluid regimes will improve our knowledge of how to target and exploit economic deposits. This study shows that multiple fluid phases penetrated the surrounding fenite aureole during carbonatite emplacement at Chilwa Island, Malawi. The first alkaline fluids formed the main fenite assemblage and later microscopic vein networks contain the minerals of potential economic interest such as pyrochlore in high-grade fenite and RE minerals throughout the aureole. Seventeen samples of fenite rock from the metasomatic aureole around the Chilwa Island carbonatite complex were chosen for study (Natural History Museum, London collection BM1968 P37). In addition to the main fenite assemblage of feldspar and aegirine ± arfvedsonite, riebeckite and richterite, the fenite contains micro-mineral assemblages including apatite, ilmenite, rutile, magnetite, zircon, RE minerals and pyrochlore in vein networks. Petrography using SEM-EDX showed that the RE minerals (monazite, bastnäsite and parisite) formed later than the fenite feldspar, aegirine and apatite and provide evidence of REE mobility into all grades of fenite. Fenite apatite has a distinct negative Eu anomaly (determined by LA-ICP-MS) that is rare in carbonatite-associated rocks and interpreted as related to pre-crystallisation of plagioclase and co-crystallisation with K-feldspar in the fenite. The fenite minerals have consistently higher mid REE/light REE ratios (La/Sm = ~1.3 monazite, ~1.9 bastnäsite, ~1.2 parisite) than their counterparts in the carbonatites (La/Sm = ~2.5 monazite, ~4.2 bastnäsite, ~3.4 parisite). Quartz in the low- and medium-grade fenite hosts fluid inclusions, typically a few µm in diameter, secondary and extremely heterogeneous. Single phase, 2- and 3-phase, single solid and multi solid-bearing examples are present, with 2-phase the most abundant. Calcite, nahcolite, burbankite and barite were found in the inclusions. Decrepitation of inclusions occurred at around 200?C before homogenisation but melting temperature data indicate that the inclusions contain relatively pure CO2. A minimum salinity of around 24 wt.% NaCl equivalent was determined. Among the trace elements in whole rock analyses, enrichment in Ba, Mo, Nb, Pb, Sr, Th and Y and depletion in Co, Hf and V are common to carbonatite and fenite but enrichment in carbonatitic type elements (Ba, Nb, Sr, Th, Y, and REE) generally increases towards the inner parts of the aureole. A schematic model contains multiple fluid events, related to first and second boiling of the magma, accompanying intrusion of the carbonatites at Chilwa Island, each contributing to the mineralogy and chemistry of the fenite. The presence of distinct RE mineral micro-assemblages in fenite at some distance from carbonatite could be developed as an exploration indicator of REE enrichment.
DS201803-0444
2017
Rankin, A.H.Dowman, E., Wall, F., Treloar, P.J., Rankin, A.H.Rare earth mobility as a result of multiple phases of fluid activity in fenite around the Chilwa Island carbonatite, Malawi.Mineralogical Magazine, Vol. 81, 6, pp. 1367-1395.Africa, Malawicarbonatite

Abstract: Carbonatites are enriched in critical raw materials such as the rare earth elements (REE), niobium, fluorspar and phosphate. A better understanding of their fluid regimes will improve our knowledge of how to target and exploit economic deposits. This study shows that multiple fluid phases penetrated the surrounding fenite aureole during carbonatite emplacement at Chilwa Island, Malawi. The first alkaline fluids formed the main fenite assemblage and later microscopic vein networks contain the minerals of potential economic interest such as pyrochlore in high-grade fenite and RE minerals throughout the aureole. Seventeen samples of fenite rock from the metasomatic aureole around the Chilwa Island carbonatite complex were chosen for study (Natural History Museum, London collection BM1968 P37). In addition to the main fenite assemblage of feldspar and aegirine ± arfvedsonite, riebeckite and richterite, the fenite contains micro-mineral assemblages including apatite, ilmenite, rutile, magnetite, zircon, RE minerals and pyrochlore in vein networks. Petrography using SEM-EDX showed that the RE minerals (monazite, bastnäsite and parisite) formed later than the fenite feldspar, aegirine and apatite and provide evidence of REE mobility into all grades of fenite. Fenite apatite has a distinct negative Eu anomaly (determined by LA-ICP-MS) that is rare in carbonatite-associated rocks and interpreted as related to pre-crystallisation of plagioclase and co-crystallisation with K-feldspar in the fenite. The fenite minerals have consistently higher mid REE/light REE ratios (La/Sm = ~1.3 monazite, ~1.9 bastnäsite, ~1.2 parisite) than their counterparts in the carbonatites (La/Sm = ~2.5 monazite, ~4.2 bastnäsite, ~3.4 parisite). Quartz in the low- and medium-grade fenite hosts fluid inclusions, typically a few µm in diameter, secondary and extremely heterogeneous. Single phase, 2- and 3-phase, single solid and multi solid-bearing examples are present, with 2-phase the most abundant. Calcite, nahcolite, burbankite and barite were found in the inclusions. Decrepitation of inclusions occurred at around 200?C before homogenisation but melting temperature data indicate that the inclusions contain relatively pure CO2. A minimum salinity of around 24 wt.% NaCl equivalent was determined. Among the trace elements in whole rock analyses, enrichment in Ba, Mo, Nb, Pb, Sr, Th and Y and depletion in Co, Hf and V are common to carbonatite and fenite but enrichment in carbonatitic type elements (Ba, Nb, Sr, Th, Y, and REE) generally increases towards the inner parts of the aureole. A schematic model contains multiple fluid events, related to first and second boiling of the magma, accompanying intrusion of the carbonatites at Chilwa Island, each contributing to the mineralogy and chemistry of the fenite. The presence of distinct RE mineral micro-assemblages in fenite at some distance from carbonatite could be developed as an exploration indicator of REE enrichment.
DS1960-1155
1969
Rankin, D.Loftus, W.K.B., Stucke, H.J., Rankin, D.Mining and Treatment Plant Practice at the Finsch MineSouth African Institute of Mining and Metallurgy. Journal, Vol. 69, No. 8, PP. 364-407.South AfricaDiamond Mining Recovery, Kimberlite Pipes
DS1990-1214
1990
Rankin, D.Rankin, D., Pascal, F.A gap in the North American central plains conductivity anomalyPhysics of the Earth and Planetary Interiors, Vol. 60, pp. 132-137MidcontinentGeophysics, Paleotectonics
DS1983-0529
1983
Rankin, D.W.Rankin, D.W., Stern, T.W., Mclelland, J., Zartman, R.E., Odom, A.Correlation Chart for Precambrian Rocks of the Eastern United States.United States Geological Survey (USGS) PROF. PAPER., No. 1241-E, 18P.GlobalMid-continent
DS1993-1285
1993
Rankin, D.W.Reed, J.C., Bickford, M.E., Houston, R.S., Link, P.K., Rankin, D.W.Precambrian: conterminous U.SGeological Society of America DNAG Volume, No. C-2, 700p. approx. $ 100.00United StatesBook -table of contents, Precambrian
DS200612-0577
2006
Rankin, D.W.Hibbard, J.P., Van Staal, C.R., Rankin, D.W., Williams, H.Lithotectonic map of the Appalachian orogen, Canada-United States of America.Geological Survey of Canada, Map 2096A 1: 1,500,000 $ 30.00Canada, United StatesMap - tectonics
DS201312-0431
2013
Rankin, L.Isles, D., Rankin, L.Geological interpretation of aeromagnetic data.Ebook, [email protected] approx. $ 100.TechnologyGeophysics - aeromag not specific to diamonds but interest
DS2003-0303
2003
Rankin, L.R.Crowe, W.A., Nash, C.R., Harris, L.B., Leeming, P.M., Rankin, L.R.The geology of the Rengali province: implications for the tectonic development ofJournal of Asian Earth Sciences, Vol. 21, 7, pp. 697-710.IndiaTectonics - not specific to diamonds
DS200412-0390
2003
Rankin, L.R.Crowe, W.A., Nash, C.R., Harris, L.B., Leeming, P.M., Rankin, L.R.The geology of the Rengali province: implications for the tectonic development of northern Orissa, India.Journal of Asian Earth Sciences, Vol. 21, 7, pp. 697-710.IndiaTectonics - not specific to diamonds
DS1986-0861
1986
Rankin, R.A.Willett, G.C., Duncan, R.K., Rankin, R.A.Geology and economic evaluation of the Mt. Weld carbonatite,Laverton Western Australia #1Proceedings of the Fourth International Kimberlite Conference, Held, No. 16, pp. 97-99AustraliaCarbonatite
DS1989-1628
1989
Rankin, R.A.Willett, G.C., Duncan, R.K., Rankin, R.A.Geology and economic evaluation of the Mt. Weldcarbonatite, Laverton Western Australia #2Geological Society of Australia Inc. Blackwell Scientific Publishing, No. 14, Vol. 2, pp. 1215-1238AustraliaCarbonatite, Mt. Weld
DS2000-0793
2000
Ranneli, G.Ranneli, G., Pellegrini, R., D'Offizi, S.Time dependence of negative bouyancy and the subduction of continental lithosphere.Journal of Geodynm., Vol. 30, No. 5, pp. 539-55.MantleSubduction
DS1994-0798
1994
Ransay, R.R.Hwang, P., Taylor, H.R., Rock, N.M.S., Ransay, R.R.Mineralogy, geochemistry and petrogenesis of the Metters bore no. 1lamproite pipe, Calwywyardah field.Mineralogy and Petrology, Vol. 51, No. 2-4, pp. 195-226.Australia, Western AustraliaLamproite, geochemistry, petrology, Deposit - Metters Bore No. 1, West Kimberley
DS1998-1205
1998
Ransom, B.Ransom, B., Kastner, M., Spivack, A.J.Chlorine fluid cycling in subduction zones: evidence chloride concentrations and chlorine stable isotopes.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1233-4.MantleSubduction
DS1920-0295
1926
Ransome, F.L.Ransome, F.L.Review of die Diamantwurste Suedwest AfrikasEconomic Geology, Vol. 21, PP. 734-736.Southwest Africa, NamibiaRegional Geology, Littoral Diamond Placers
DS1900-0212
1903
Ransome, S.Ransome, S.The Engineer in South Africa. a Review of the Industrial Situation in South Africa After the War and a Forecast of the Possibilities of the Country.Westminster: Constable And Co., 391P.Africa, South AfricaMining, Equipment, Kimberley
DS201811-2602
2018
Ranta, E.Ranta, E., Stockmann, G., Wagner, T., Fusswinkel, T., Sturkell, E., Tollefsen, E., Skelton, A.Fluid-rock reactions in the 1.3 Ga siderite carbonatite of the Gronnedal-Ika alkaline complex, southwest Greenland.Contributions to Mineralogy and Petrology, Vol. 173, 26p. Doi.org/10.1007/s00410-018-1505-yEurope, Greenlandcarbonatite

Abstract: Petrogenetic studies of carbonatites are challenging, because carbonatite mineral assemblages and mineral chemistry typically reflect both variable pressure-temperature conditions during crystallization and fluid-rock interaction caused by magmatic-hydrothermal fluids. However, this complexity results in recognizable alteration textures and trace-element signatures in the mineral archive that can be used to reconstruct the magmatic evolution and fluid-rock interaction history of carbonatites. We present new LA-ICP-MS trace-element data for magnetite, calcite, siderite, and ankerite-dolomite-kutnohorite from the iron-rich carbonatites of the 1.3 Ga Grønnedal-Íka alkaline complex, Southwest Greenland. We use these data, in combination with detailed cathodoluminescence imaging, to identify magmatic and secondary geochemical fingerprints preserved in these minerals. The chemical and textural gradients show that a 55 m-thick basaltic dike that crosscuts the carbonatite intrusion has acted as the pathway for hydrothermal fluids enriched in F and CO2, which have caused mobilization of the LREEs, Nb, Ta, Ba, Sr, Mn, and P. These fluids reacted with and altered the composition of the surrounding carbonatites up to a distance of 40 m from the dike contact and caused formation of magnetite through oxidation of siderite. Our results can be used for discrimination between primary magmatic minerals and later alteration-related assemblages in carbonatites in general, which can lead to a better understanding of how these rare rocks are formed. Our data provide evidence that siderite-bearing ferrocarbonatites can form during late stages of calciocarbonatitic magma evolution.
DS1996-1162
1996
RaoRao, NVC, Madhavran, V.Titanium rich phlogopites from the Zangamajupalle kimberlitic rock, AndhraPradesh, India.Journal of Geological Society India, Vol. 47, No. 3, March pp. 355-363.IndiaPetrography, Deposit -Zangamajupalle
DS2003-1138
2003
RaoRay, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granite province: evidence from southern IndiaJournal of Geophysical Research, Vol. 108, B2, 10.1029/2001JB000688IndiaUHP
DS2003-1139
2003
RaoRay, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granulite province: evidence from southernJournal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP, Geothermometry
DS200712-0871
2006
RaoRao, Viljaya, V., Sain, K., Reddy, P.R., Mooney, W.D.Crustal structure and tectonics of the northern part of the southern Granulite Terrane, India.Earth and Planetary Science Letters, Vol. 251, 1-2, Nov. 15, pp.90-103.IndiaTectonics - not specific to diamonds
DS1970-0809
1973
Rao, A.V.K.Rajaraman, S., Rao, A.V.K.Report on the Investigation for Diamond Carries Out in Pipe-1 in Wajrakarur, Anantapur District, Andhra Pradesh.India Geological Survey Program Report, FOR 1968-1973India, Andhra PradeshDiamond Prospecting
DS1986-0321
1986
Rao, A.V.R.Guptasarma, D., Chetty, T.R.K., Murthy, D.S.N*n., Rao, A.V.R.Discovery of a new kimberlite pipe in Andhra Pradesh by streamsedimentsamplingJournal of Geological Society India, Vol. 27, No. 3, March pp. 313-316IndiaGeochemistry
DS1975-0388
1976
Rao, B.B.Rao, B.B.A Note on the Micaceous Kimberlitic Dyke in the Cumbum Formation Near Zangamrajupalle Cuddapah District.Indian Minerals, Vol. 30, No. 1, PP. 55-58.India, Andhra PradeshMineralogy, Petrography
DS1994-1265
1994
Rao, B.B.Natarajan, M., Rao, B.B., Parthasan, R., Kumar, A.2, 0 GA old pyroxenite-carbonatite complex of Hogenakal, Tamil-Nadu, SouthIndia.Precambrian Research, Vol. 65, No. 1-4, January pp. 167-181.IndiaCarbonatite, Geochronology
DS1995-1072
1995
Rao, B.B.Le Bas, M.J., Rao, B.B.Are the Vinjamur rocks carbonatites or meta-limestones?Journal of Geological Society India, Vol. 46, No. 2, August pp. 125-138.IndiaCarbonatite
DS1988-0498
1988
Rao, B.K.N.Nayak, S.S., Viswanathan, C.V.K., Reddy, T.A.K., Rao, B.K.N.New find of kimberlitic rocks in Andhra Pradesh near Maddur,MahaboobnagarDistrictJournal of Geological Society India, Vol. 31, No. 3, March pp. 343-346IndiaBlank
DS1987-0162
1987
Rao, B.V.Dressler, B.O., Morrison, G.G., Peredery, W.V., Rao, B.V.The Sudbury structure, Ontario, Canada- a ReviewBraunschweig Wiesbaden Vieweg, pp. 39-68OntarioSudbury, Impact structure
DS1995-1543
1995
Rao, C.Rao, C., et al.Petrochemistry and significance of the Ramannapeta lamproite, KrishnaValley, Andhra Pradesh.Terra Nova, Abstract Vol., p. 295.IndiaLamproite
DS200412-0684
2004
Rao, C.K.Gokarn, S.G., Gupta, G., Rao, C.K.Geoelectric structure of the Dharwar Craton from magnetotelluric studies: Archean suture identified along the Chitradurga GadagGeophysical Journal International, Vol. 158, 2, pp. 712-728.IndiaGeophysics - magnetotellurics
DS200412-1621
2004
Rao, C.K.Rao, C.K., Ogawa, Y., Gokarn, S.G., Gupta, G.Electromagnetic imaging of magma across the Narmada Son lineament, central India.Earth Planets and Space, Vol. 56, 2, pp. 229-238.. IngentaIndiaGeophysics - magnotellurics
DS201412-0302
2013
Rao, C.K.Gokarn, S.G., Rao, C.K., Selvaraj, C., Gupta, G., Singh, B.P.Crustal evolution and tectonics of the Archean Bundelk hand craton, central India.Journal of the Geological Society of India, Vol. 82, No. 5, pp. 455-460.IndiaTectonics
DS1996-1157
1996
Rao, C.N.V.Rao, C.N.V., Miller, J.A., Pyle, D.M., Madhavan, V.New Proterozoic K-Ar ages for some kimberlites and lamproites from the Cuddapah Basin, Dharwar Craton:Precambrian Research, Vol. 79, pp. 363-369.India, MahbubnagarLamproite, Geochronology, Deposit -Ramannapeta, Kotakonda, Chelima
DS1996-1158
1996
Rao, C.N.V.Rao, C.N.V., Reed, S.J.B., Beattie, P.D.Larnitic kirschsteinite from the Kotakonda kimberlite, Andhra Pradesh, India.Mineralogical Magazine, Vol. 60, pt. 3, June 1, pp. 513-516.IndiaMineralogy, Deposit -Katakonda
DS200812-0858
2008
Rao, C.R.M.Patel, S.C., Ravi, S., Rao, C.R.M., Rama Rao, G., Nayak, S.S.Mineralogy and geochemistry of Wajrakaruru kimberlites, southen India.9IKC.com, 3p. extended abstractIndiaDeposit - Wajrakarur petrography
DS1989-1442
1989
Rao, C.V.R.Sringesh, D., Rai, S.S., Ramesh, D.S., Gaur, V.K., Rao, C.V.R.Evidence for thick continental roots beneath South Indian shieldGeophysical Research Letters, Vol. 16, No. 9, September pp. 1055-1058IndiaMantle
DS1996-1159
1996
Rao, D. Atchuta.Rao, D. Atchuta.Intra crustal structure inferred from aeromagnetics Eastern Dharwar Craton and its significance kimberliteJournal of Geological Society India, Vol. 48, No. 4, Oct. pp. 391-402.IndiaGeophysics -aeomagnetics, Kimberlite exploration
DS1981-0344
1981
Rao, D.A.Rao, D.A., Sanker narayan, P.V.Structural Control of Emplacement of Kimberlite Pipes at Panna- a Suggestion from Aeromagnetics.Geoexploration., Vol. 19, PP. 207-228.India, Madhya PradeshKimberlite, Geophysics, Airmag
DS1991-1398
1991
Rao, D.BRao, D.B, Babu, N.R.A FORTRAN 77 Computer program for a 3-dimensional analysis of gravity anomalies with variable density contrastJournal of Geophysical Research, Vol. 17, No. 5, pp. 655-668GlobalGravity anomalies
DS200412-1622
2004
Rao, D.G.Rao, D.G., Krishna, K.S., Neprochnov, Yu.P., Grinko, B.N.Satellite gravity anomalies and crustal features of the central Indian Ocean basin.Current Science, Vol. 86, 7, April 10, pp. 948-957.IndiaTectonics, crustal, lineaments
DS200812-0936
2008
Rao, D.V.S.Rao, D.V.S., Balaram, V., Raju, K.N., Sridhar, D.N.Paleoproterozoic boninite like rocks in an intracratonic setting from northern Bastar Craton, central India.Journal of the Geological Society of India, Vol. 27, 3, pp. 373-380.IndiaBoninites
DS2003-1138
2003
Rao, G.V.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granite province: evidence from southern IndiaJournal of Geophysical Research, Vol. 108, B2, 10.1029/2001JB000688IndiaUHP
DS2003-1139
2003
Rao, G.V.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granulite province: evidence from southernJournal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP, Geothermometry
DS200412-1637
2003
Rao, G.V.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., Rao, R.U.M.High mantle heat flow in a Precambrian granulite province: evidence from southern India.Journal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP Geothermometry
DS1991-0198
1991
Rao, H.V.Burra Subrahmanyam, B., Subba Rao, J.A.V.R.K., Rao, H.V.Three probable locations for kimberlites in Wajrakarur -Lattavaram -P.C.Pyapilli area, Andhra PradeshJournal of Geological Society India, Vol. 37, May pp. 443-451IndiaKimberlite, Geophysics -gravity
DS201603-0416
2016
Rao, I.Rao, I.When culture governs business practice: a look at Indian diamond cutting and polishing industry.Global Business and Organizational Excellence, Vol. 35, 3, pp. 6-17.IndiaCutting and polishing industry

Abstract: As informal firms in emerging markets are expanding their role in global supply chains, managers of formal multinational organizations are increasingly relying on their services. Yet, little is known about the organizational aspects of enterprises in the informal sector. An investigation of informal firms engaged in the cutting and polishing of diamonds (CPD) in Surat, India, the world's hub of diamond manufacturing, reveals that in the absence of well-defined strategies, structures, and processes, the intangible aspect of organizing—specifically, organizational culture—governs business practices. Despite the strong clan-like orientation of these firms and a culture focused on loyalty, trust, team work, and consensus, the study found evidence of hierarchical characteristics and market-driven leadership. Coupled with insightful observations of the overall Indian CPD sector, these findings can help guide managers in planning strategies for effective partnerships with informal firms, regardless of their industry.
DS2002-1302
2002
Rao, I.B.R.Ramadass, G., Rao, I.B.R., Himabindu, D., SrinivasuluPseudo surface velocities (densities) and pseudo depth densities along profiles Dharwar Craton, India.Current Science, Vol.82,No.2, pp. 197-201.IndiaGeophysics - seismics, Craton - Dharwar
DS2003-1126
2003
Rao, I.B.R.Ramadass, G., Rao, I.B.R., Srinivasulu, N., Himabindu, D.Density studies in the Dharwar Craton along the Jadcharla Goa subtransectJournal Geological Society of India, Vol. 61, 4, pp. 439-448.IndiaGeophysics - seismics
DS200412-1615
2003
Rao, I.B.R.Ramadass, G., Rao, I.B.R., Srinivasulu, N., Himabindu, D.Density studies in the Dharwar Craton along the Jadcharla Goa subtransect.Journal Geological Society of India, Vol. 61, 4, pp. 439-448.IndiaGeophysics - seismics
DS200512-0888
2005
Rao, I.B.R.Ramadass, G., Rao, I.B.R., Himabindu, D.Regional appraisal from gravity investigations in the Dharwar Craton: Jadcharla - Goa transect.Journal of the Geological Society of India, Vol. 65, 1, pp. 61-69.IndiaGeophysics - gravity not specific to diamonds
DS1989-0118
1989
Rao, J.M.Bhattacharji, S., Rao, J.M.Mafic dikes and dike swarms around Proterozoic Cuddapah Basin, south India:their mode of emplacement and geodynamic significanceNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 24. AbstractIndiaDykes
DS1990-0974
1990
Rao, J.M.Madhaven, V., Rao, J.M., Sprininasan, T.P., Sprininansan, M.The mid-Proterozoic dyke swarm of mica lamprophyres and microshonkinites from Elchuru IndiaMafic dykes and emplacement mechanisms, Editors A.J. Parker, P.C., pp. 363-372IndiaLamprophyric dykes, Shonkinites
DS1993-1283
1993
Rao, J.M.Rao, J.M., Charan, S.N.Petrography and geochemistry of the pipe 7 kimberlite, Arantapur Andhra Pradesh India.Journal of Geological Society India, Vol. 42, No. 5, November pp. 469-480.IndiaPetrography, Arantapur -Pipe 7
DS1999-0435
1999
Rao, J.M.Madhaven, V., Rao, J.M., Srinivas, M.Mid Proterozoic intraplate alkaline magmatism in the eastern Dharwar Craton of India: the Cuddapah ProvinceJournal of Geological Society IndiaM., Vol. 53, No. 2, Feb. 1, pp. 143-62.India, CuddapahAlkaline rocks, Magmatism, Craton
DS200612-1126
2001
Rao, K.N.Rao, K.R.P., Rao, K.N., Dhakate, M.V., Nayak, S.S.Petrology and mineralogy of mantle xenoliths of Wajrakarur and Narayanpet kimberlite fields, Andhra Pradesh, India.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 577-591.India, Andhra PradeshXenoliths
DS2002-1307
2002
Rao, K.R.Rao, K.R.Elemental osmium: the latest superhard materialCurrent Science, Vol.82,10,May 25, pp. 1198-2001.GlobalOsmium - brief overview
DS2002-1308
2002
Rao, K.R.Rao, K.R.Nuclear reactor at the core of the Earth! - a solution to the riddles of relative abundances of helium isotopes and geomagnetic field variability.Current Research, Vol. 82, No. 2, Jan. 25, pp. 126-7.MantleHelium isotopes
DS1998-1206
1998
Rao, K.R.P.Rao, K.R.P., Reddy, T.A.K., Rao, N.V.Geology, petrology and geochemistry of Narayanpet kimberlites in Andhra Pradesh and Karnataka.Journal of Geological Society India, Vol. 52, No. 6, Dec. pp. 663-76.India, South IndiaKimberlites, Deposit - Narayanpet, Krishna, Bhima Rivers
DS1999-0579
1999
Rao, K.R.P.Rao, K.R.P.Compositional study of spinels from Wajrakarur Pipe 10 (Anumpalle) and its significance in diamond prospectingJournal of Geological Society India, Vol. 53, No. 5, May pp. 617-IndiaMineralogy - spinels, Deposit - Wajrakarur Pipe 10
DS1999-0584
1999
Rao, K.R.P.Ravi, S., Bhaskara Rao, K.S., Rao, K.R.P.Search for kimberlites in the granite greenstone terrain in the central segment of Wajrakarur kimberlite field, Anantapur district.Geological Society of India Records, Vol. 132,5, pp.40-43.India, Andhra PradeshKimberlite
DS1999-0722
1999
Rao, K.R.P.Suresh, G., Dhakate, M.V., Rao, K.R.P.Delineation and assessment of Diamondiferous nature of Chintalampalle ( P -12) and Gollapalle ( CC-5) kimberlites, Anantapur District.Geological Society of India Records, Vol. 132, 5, pp. 45-9.India, Andhra PradeshDiamond - resources
DS2002-1309
2002
Rao, K.R.P.Rao, K.R.P.Comments on: pattern of occurrence of kimberlite pipes based on gravity and magnetic anomalies in Wajrakarur Lattavaram region, Andhra Pradesh by Vasanthi and MallicJournal of the Geological Society of India, Vol. 60, 4, Sept. pp. 350-352.India, Andhra PradeshGeophysics - gravity, magnetics
DS200412-1067
2001
Rao, K.R.P.Kumar, A., Gopalan, K., Rao, K.R.P., Nayak, S.S.Rb Sr ages of kimberlites and lamproites from eastern Dhawar Craton, South India.Journal of the Geological Society of India, Vol. 58, pp. 135-142.IndiaGeochronology
DS200412-1414
2001
Rao, K.R.P.Nayak, S.S., Rao, K.R.P., Kudari, S.A.K., Ravi, S.Geology and tectonic setting of kimberlites and lamproites of southern India.Geological Society of India Special Publication, No.58, pp. 603-613.IndiaTectonics
DS200412-1623
2002
Rao, K.R.P.Rao, K.R.P.Comments on: pattern of occurrence of kimberlite pipes based on gravity and magnetic anomalies in Wajrakarur Lattavaram region,Journal of the Geological Society of India, Vol. 60, 4, Sept. pp. 350-352.India, Andhra PradeshGeophysics - gravity, magnetics
DS200612-0968
2001
Rao, K.R.P.Nayak, S.S., Rao, K.R.P., Kudati, S.A.D., Ravi, S.Geology and tectonic setting of the kimberlites and lamproites of southern India. Wajrakarur, Natayanpet, Dharwar Craton, Chigicherla.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 567-575.India, Andhra PradeshTectonics
DS200612-1125
2001
Rao, K.R.P.Rao, K.R.P., Nayak, S.S., Reddy, T.A.K., Dhakate, M.V., Chowdary, V.S., Ravi, S., Suresh, G., Rao, K.S.B.Geology, petrology, geochemistry and mineral chemistry of new kimberlite fields in the Wajrakarur kimberlite field, Anantapur district, Andhra Pradesh.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 593-602.India, Andhra PradeshGeochemistry
DS200612-1126
2001
Rao, K.R.P.Rao, K.R.P., Rao, K.N., Dhakate, M.V., Nayak, S.S.Petrology and mineralogy of mantle xenoliths of Wajrakarur and Narayanpet kimberlite fields, Andhra Pradesh, India.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 577-591.India, Andhra PradeshXenoliths
DS1992-0237
1992
Rao, K.S.Chatterjee, A.K., Rao, K.S.Majhgawan Diamondiferous pipe (Madhya Pradesh India) a geologicalappraisalInternational Roundtable Conference on Diamond Exploration and Mining, held, pp. 189-208IndiaGeology, Deposit -Majhgawan
DS1995-0293
1995
Rao, K.S.Chatterjee, A.K., Rao, K.S.Majhgawan Diamondiferous pipe, Madhya Pradesh India - a reviewJournal of Geological Society India, Vol. 45, Feb. pp. 175-189.IndiaKimberlite, lamproite, Deposit -Majhgawan
DS1997-0825
1997
Rao, K.S.Mukherjee, A., Rao, K.S., Chatterjee, A.K.Chemistry of phlogopite megacrysts in Majhgaman Diamondiferous pipe, Madhya Pradesh.Journal of Geological Society India, Vol. 49, No. 2, Feb. pp. 203-206.IndiaGeochemistry, Deposit - Majhgaman
DS1998-1054
1998
Rao, K.S.Mukherjee, A., Rao, K.S., Babu, E.V.S.S.K.Cluster analysis and nickel thermometry of garnet xenocrysts from Majhgawan diamondiferous pipe, Panna.Journal of Geological Society India, Vol. 52, No. 3, Sept. pp. 273-278.India, Madhya PradeshGeothermometry, Deposit - Majhgawan
DS1998-1207
1998
Rao, K.S.Rao, K.S., Babu, E.V.S.S.K., Roy, G.Compositional study of spinels from Wajrakarur Pipe 10 (Anumpalle)Ananthapur District diamond prospectivityJournal of Geological Society India, Vol. 52, No. 6, Dec. pp. 677-82.IndiaPetrology - spinels, Deposit - Pipe 10
DS200612-0875
2001
Rao, K.S.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
DS200612-1125
2001
Rao, K.S.B.Rao, K.R.P., Nayak, S.S., Reddy, T.A.K., Dhakate, M.V., Chowdary, V.S., Ravi, S., Suresh, G., Rao, K.S.B.Geology, petrology, geochemistry and mineral chemistry of new kimberlite fields in the Wajrakarur kimberlite field, Anantapur district, Andhra Pradesh.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 593-602.India, Andhra PradeshGeochemistry
DS201508-0346
2015
Rao, K.V.S.Chalapathi Rao, N.V., Atiullah, Kumar, A., Sahoo, S., Nanda, P., Chahong, N., Lehmann, B., Rao, K.V.S.Petrogenesis of Mesoproterozoic lamproite dykes from the Garledinne (Banganapalle) cluster, south western Cuddapah Basin, southern India.Mineralogy and Petrology, in press available 22p.IndiaLamproite

Abstract: We report mineral chemistry and whole-rock major and trace-element geochemistry for a recent find of Mesoproterozoic (~1.4 Ga) lamproites from the Garledinne (Banganapalle) cluster, south-western part of the Paleo-Mesoproterozoic Cuddapah Basin, southern India. The Garledinne lamproites occur as WNW-ESE-trending dykes that have undergone varying degree of pervasive silicification and carbonate alteration. Nevertheless, their overall texture and relict mineralogy remain intact and provide important insights into the nature of their magmas. The lamproite dykes have porphyritic to weakly porphyritic textures comprising pseudomorphed olivine macrocrysts and microphenocrysts, titanian phlogopite microphenocrysts, spinel having a compositional range from chromite to rarely magnesiochromite, Sr-rich apatite and niobian rutile. The Garledinne and other Cuddapah Basin lamproites (Chelima and Zangamarajupalle) collectively lack sanidine, clinopyroxene, potassic richterite, and titanite and are thus mineralogically distinct from the nearby Mesoproterozoic lamproites (Krishna and Ramadugu) in the Eastern Dharwar Craton, southern India. The strong correlation between various major and trace elements coupled with high abundances of incompatible and compatible trace elements imply that alteration and crustal contamination have had a limited effect on the whole-rock geochemistry (apart from K2O and CaO) of the Garledinne lamproites and that olivine fractionation played an important role in their evolution. The Garledinne lamproites represent small-degree partial melts derived from a refractory (previously melt extracted) peridotitic mantle source that was subsequently metasomatised (enriched) by carbonate-rich fluids/melts within the garnet stability field. The involvement of multiple reservoirs (sub-continental lithospheric mantle and asthenosphere) has been inferred in their genesis. The emplacement of the Garledinne lamproites is linked to extensional events, across the various Indian cratons, related to the break-up of the Proterozoic supercontinent of Columbia.
DS1970-0811
1973
Rao, M.G.Rao, M.G.Alkalic Lamprophyres from Garo Hills, AssamIndia Geological Survey Records, Vol. 105, PT. 2, PP. 121-124.India, AssamMineralogy
DS1975-0601
1977
Rao, M.G.Rao, M.G., Misra, R.C.Investigation for Diamonds in Wajrakarur and Lattivaram Areas, Anantapur District, A.p.Geological Survey INDIA PROGR. Report, FOR 1974-1977India, Andhra PradeshDiamond Prospecting
DS200412-1841
2004
Rao, M.R.K.Singh, A.P., Mishra, D.C., Gupta, S.B., Rao, M.R.K.Crustal structure and domain tectonics of the Dharwar Craton ( India): insights from new gravity data.Journal of Asian Earth Sciences, Vol. 23, 1, March pp. 141-152.IndiaTectonics, geophysics - gravity, continental collision
DS200412-1624
2004
Rao, M.S.Rao, M.S., Fareeduddin, Godhavari, K.S., Chander, S., Sisodia, C.P.Carbonaceous metaexhalite of shungitic affinity in Paleoproterozoic Aravelli Supergroup, Dugocha area, Rajasthan.Journal Geological Society of India, Vol. 63, 5, pp. 522-532IndiaCarbon, graphite
DS2002-1310
2002
Rao, M.V.S.Rao, M.V.S., Narayana, B.L.Geochemistry and petrogenesis of Kunduru Betta calc alkaline ring complex in the Dharwar Craton.Gondwana Research, Vol. 5,2,pp. 453-66.India, southernAlkaline rocks
DS1996-1160
1996
Rao, N.V.Rao, N.V., Chalapthi, Madhaven, V.A new look at the olivine lamproitic rocks of the Maddur Narayanpet area, Mahbubnagar District, A.P.Journal of Geological Society India, Vol. 47, No. 6, June pp. 549-664.IndiaLamproites, Deposit -Maddur Narayanpet
DS1998-1206
1998
Rao, N.V.Rao, K.R.P., Reddy, T.A.K., Rao, N.V.Geology, petrology and geochemistry of Narayanpet kimberlites in Andhra Pradesh and Karnataka.Journal of Geological Society India, Vol. 52, No. 6, Dec. pp. 663-76.India, South IndiaKimberlites, Deposit - Narayanpet, Krishna, Bhima Rivers
DS1996-1161
1996
Rao, N.V.C.Rao, N.V.C., Madhavan, V.Some observations on the geochemistry of Ramannapeta -Ustapalle lamproiticbody, Krishna District AP.Journal of Geological Society India, Vol. 47, No. 4, Apr. 1, pp. 409-418.IndiaLamproite, Deposit -Ramannapeta-Ustapalle
DS1999-0580
1999
Rao, N.V.C.Rao, N.V.C., Miller, J.A., Madhavan, V.Precise 40 Ar-39 Ar age determinations of the Kotonda kimberlite and Chelima lamproite : implications timingJournal of Geological Society India, Vol. 53, No. 4, Apr. pp. 425-32.IndiaGeochronology - mafic dyke swarm emplacement, Argon, Craton - Dharwar
DS200612-1127
2006
Rao, N.V.C.Rao, N.V.C.Mesoproterozoic Diamondiferous ultramafic pipes at Majkgawan and Hinota, Panna area, central India: key to the nature of sub-continental lithospheric mantle...Journal of Earth System Science, Vol. 115, 1m pp. 161-183.Asia, IndiaVindhyan Basin
DS200812-0937
2008
Rao, N.V.C.Rao, N.V.C.Precambrian alkaline potassic ultrapotassic mafic ultramafic magmatism in Peninsular India.Journal of the Geological Society of India, Vol. 72, 1, pp. 57-74.IndiaAlkalic
DS201912-2797
2019
Rao, N.V.ChalapthiKumar, R.K., Praveer, P., Rao, N.V.Chalapthi, Chakrabarti, R., Pandit, D.Petrogenesis of an alkaline lamprophyre ( camptonite) with ocean island basalt ( OIB)-affinity at the NW margin of the Cuddapah Basin, eastern Dharwar craton, southern India.Neues Jahbuch fur Mineralogy, Vol. 196, p2, pp. 149-177.Indiacamptonite

Abstract: We report petrology and geochemistry (including Sr and Nd isotopes) of a fresh lamprophyre at Ankiraopalli area at the north-western margin of Paleo-Mesoproterozoic Cuddapah basin, eastern Dharwar craton, southern India. Ankiraopalli samples possess a typical lamprophyre porphyritic-panidiomorphic texture with phenocrysts of kaersutite and diopside set in a plagioclase dominant groundmass. Combined mineralogy and geochemistry classify it as alkaline lampro- phyre in general and camptonite in particular. Contrary to the calc-alkaline and/or shoshonitic orogenic nature portrayed by lamprophyres occurring towards the western margin of the Cuddapah basin, the Ankiraopalli samples display trace element composition revealing striking similarity with those of ocean island basalts, Italian alkaline lamprophyres and highlights an anorogenic character. However, the87 Sr/86 Srinitial (0.710316 to 0.720016) and ?Ndinitial (- 9.54 to - 9.61) of the Ankiraopalli lamprophyre show derivation from an 'enriched' mantle source showing long term enrichment of incompatible trace elements and contrast from those of (i) OIB, and (ii) nearby Mahbubnagar alkaline mafic dykes of OIB affinity. Combining results of this study and recent advances made, multiple mantle domains are identified in the Eastern Dharwar craton which generated distinct Mesoproterozoic lamprophyre varieties. These include (i) Domain I, involving sub-continental lithospheric mantle source essentially metasomatized by subduction-derived melts/fluids (represented by orogenic calcalkaline and/or shoshonitic lamprophyres at the Mudigubba, the Udiripikonda and the Kadiri); (ii) Domain II, comprising a mixed sub-continental lithospheric and asthenospheric source (represented by orogenic-anorogenic, alkaline to calc-alkaline transitional lamprophyres at the Korakkodu), and (iii) Domain III, representing a sub-continental lithospheric source with a dominant overprint of an asthenospheric (plume) component (represented by essentially alkaline lamprophyres at the Ankiraopalli). Our study highlights the varied mantle source heterogeneities and complexity of geodynamic processes involved in the Neoarchean-Paleo/Mesoproterozoic evolution of the Eastern Dharwar craton.
DS1995-1544
1995
Rao, N.Y.C.Rao, N.Y.C.A new occurrence of kimberlite near Kotakonda Mahboobnagar District, AndhraPradesh. #2Journal of Geological Society India, Vol. 45, No. 5, May pp. 605-606.IndiaKimberlite
DS1950-0234
1955
Rao, P.Rao, P.Preliminary Investigation of Old Diamond Workings in Hyderabad State.India Geological Survey, UNPUB. ReportIndiaProspecting
DS1960-0184
1961
Rao, P.S.Rao, P.S.The Geology and Mineral Deposits of the Southern and Western Extension of Gani Copper Belt, Kurnool District.Geological Survey INDIA UNPUBL. REPORT, FOR 1959-1960., India, Andhra PradeshProspecting
DS1960-0387
1963
Rao, P.S.Rao, P.S., Phadtre, P.N.Investigation for Diamond in Wajrakarur, Anantapur DistrictIndia Geological Survey, UNPUBL. ReportIndiaProspecting
DS1960-0388
1963
Rao, P.S.Rao, P.S., Phadtre, P.N.Investigation for Diamonds in Wajrakarur Area Anatapur District, A.p.India Geological Survey Program Report, FOR 1961-1963, PP.India, Andhra PradeshProspecting
DS1960-0489
1964
Rao, P.S.Rao, P.S., Konala, R.K.R.Prospecting for Lead, Zinc and Diamond in Cuddapah and Kurnool Districts.India Geological Survey, UNPUBL. ReportIndia, Madhya PradeshProspecting
DS1960-0732
1966
Rao, P.S.Rao, P.S., Phadtre, P.N.Kimberlite Pipe Rocks of Wajrakarur, Anantapur DistrictGeological Society INDIA Journal, Vol. 7, PP. 118-123.India, Andhra PradeshGeology
DS1975-0906
1979
Rao, P.S.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
DS1930-0118
1932
Rao, R.M.B.Pichamuthu, C.S., Rao, R.M.B.A Note on the Tuff of WajrakarurIndian Sci. Congr. 19th. Session Proceedings, ABSTRACT.India, Andhra PradeshPetrography
DS1986-0140
1986
Rao, R.S.Chetty, T.R.K., Rao, R.S.Proto Penner river course and its role in the distribution of alluvial diamonds- as evidence from Land sat dataJournal of Geological Society India, Vol. 28, No. 6, December, pp. 48-IndiaRemote Sensing, Placers
DS2003-1192
2003
Rao, R.U.Roy, S., Rao, R.U.Towards a crustal thermal model for the Archean Dharwar craton, southern IndiaPhysics and Chemistry of the Earth, parts A,B,C, Vol. 28, 9-11, pp. 361-73.IndiaBlank
DS200412-1696
2003
Rao, R.U.Roy, S., Rao, R.U.Towards a crustal thermal model for the Archean Dharwar craton, southern India.Physics and Chemistry of the Earth Parts A,B,C, Vol. 28, 9-11, pp. 361-73.IndiaGeothermometry
DS2000-0838
2000
Rao, R.U.M.Roy, S., Rao, R.U.M.Heat flow in the Indian ShieldJournal of Geophysical Research, Vol.105, No.11, Nov.10, pp.25587-604.IndiaGeothermometry, Heat flow
DS200412-1637
2003
Rao, R.U.M.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., Rao, R.U.M.High mantle heat flow in a Precambrian granulite province: evidence from southern India.Journal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP Geothermometry
DS1996-1163
1996
Rao, S.D.V.Rao, S.D.V.Resolving Bouguer anomalies in continents: a new approachGeophysical Research. Letters, Vol. 23, No. 24, Dec. 1, pp. 3543-46.MantleGeophysics - seismics
DS1992-1252
1992
Rao, S.R.Rao, S.R., et al.Waste processing and recycling in mining and metallurgical industries.Proceedings Volume from meetingCanadian Institute of Mining and Metallurgy (CIMM) Society, 366p. no price givenGlobalBook review, Metallurgy and recycling
DS1996-0554
1996
Rao, S.V.Gowd, T.N., Srirama, Rao, S.V., Chary, K.B.Stress field and seismicity in the Indian shield: effects of the collision between India and Eurasia.Pure and Applied Geophysics, Vol. 146, No. 3-4, May 1, pp. 503-532.India, EurasiaTectonics, Geophysics -seismics
DS200912-0649
2007
Rao, T.Roy, P.,Balaram, V., Kumar, A., Sathyanarayan, M., Gnaneshwara, Rao, T.New REE and trace element dat a on two kimberlite reference materials by ICP-MS.Geostandards and Geoanalytical Research, Vol. 31, pp. 261-273.IndiaGeochronology
DS1960-0050
1960
Rao, T.C.Gokhale, K.V.G.K., Rao, T.C.Ore Deposits of India: Diamond DepositsDelhi: Thomson Press, PP. 117-122; PP. 214-215.IndiaGeology, Diamond Occurrences
DS1990-1215
1990
Rao, T.C.Rao, T.C., Vanangamudi, M., Barnwal, J.P.Industrial application of heavy medium cyclone modelAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Meeting, Salt Lake City, February 26, Preprint?GlobalHeavy medium Application, Mineral processing -gener
DS200512-0681
2005
Rao, T.G.Manikyamba, C., Naqvi, S.M., Subba Rao, D.V., Ram Mohan, M., Khanna, T.C., Rao, T.G., Reddy, G.L.Boninites from the Neoarchean Gadwal greenstone belt, eastern Dharwar Craton, India, implications for Archean subduction processes.Earth and Planetary Science Letters, Vol. 230, 1-2, pp. 65-83.IndiaBoninites
DS200612-0858
2005
Rao, T.G.Manikyamba, C., Khanna, T.C., Subba Rao, D.V., Charan, S.N., Rao, T.G.Geochemistry and petrogenesis of Gadwai kimberlites, eastern Dharwar Craton India.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 67-68.India, Andhra Pradesh, Dharwar CratonKimberlite - Gadwai
DS1994-1439
1994
Rao, T.K.Rao, T.K., Sarma, K.J.A new occurrence of kimberlite near Kotakonda, Mahboobhagar district, Andhra Pradesh.Journal Geological Society of India, Vol. 43, No. 1, January pp. 78-85.IndiaKimberlite
DS1995-1545
1995
Rao, T.K.Rao, T.K.A new occurrence of kimberlite near Kotakonda Mahboobnagar District, AndhraPradesh... reply #3Journal of Geological Society India, Vol. 45, No. 5, May pp. 606-607.IndiaKimberlite
DS200612-0970
2005
Rao, T.K.Nayak, S.S., Ravi, S., Sridhar, M., Reddy, N.S., Chowdary, V.S., Bhaskara Rao, K.S., Sinha, K.K., Rao, T.K.Geology and tectonic setting of kimberlites of Dharwar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 36-38.India, Andhra Pradesh, Dharwar CratonTectonics
DS200612-1046
2006
Rao, T.K.Patel, S.C., Ravi, S., Thakur, S.S., Rao, T.K., Subbarao, K.V.Eclogite xenoliths from Wajrakarur kimberlites, southern India.Mineralogy and Petrology., Vol. 88, 1-2, pp. 363-380.IndiaDeposit - Wajrakarur petrology
DS200612-1047
2006
Rao, T.K.Patel, S.C., Ravi,S., Thakur, S.S., Rao, T.K., Subbarao, K.V.Eclogite xenoliths from Wajrakarur kimberlites, southern India.Mineralogy and Petrology, Vol. 88, 1-2, pp. 363-380.IndiaDeposit - Wajrakarur
DS2000-0775
2000
Rao, V.K.Prakasa, R.G.S., Tewari, H.C., Rao, V.K.Velocity structure in parts of the Gondwana Godavari GrabenJournal of Geological Society India, Vol. 56, No. 4, Oct. 1, pp. 373-84.IndiaTectonics, Graben - not specific to diamonds
DS201706-1087
2017
Rao, V.K.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.
DS201801-0033
2018
Rao, V.K.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.
DS1998-1208
1998
Rao, V.V.Rao, V.V., Gupta, H.K., Tewari, H.C.A geotransect in the Central Indian Shield, across the Narmada Sonlineament and the Central Indian Suture.International Geology Review, Vol. 40, No. 11, Nov. pp. 1021-IndiaTectonics
DS2003-1371
2003
Rao, V.V.Tewari, H.C., Rao, V.V.Structure and tectonics of the Proterozoic Aravalli Delhi geological province, NWMemoirs Geological Society of India, Vol. 53, pp. 57-78. Ingenta 1035483296IndiaBlank
DS200412-1981
2003
Rao, V.V.Tewari, H.C., Rao, V.V.Structure and tectonics of the Proterozoic Aravalli Delhi geological province, NW Indian Peninsular Shield.Memoirs Geological Society of India, Vol. 53, pp. 57-78. Ingenta 1035483296IndiaTectonics
DS200712-0870
2007
Rao, V.V.Rao, V.V., Sain, K., Prasad, B.R.Dipping Moho in the southern part of Eastern Dharwar Craton, India as revealed by the coincident seismic reflection and refraction study.Current Science, Vol. 93, 3, Aug. 10, pp. 330-336.IndiaGeophysics - seismics
DS200812-0938
2008
Rao, V.V.Rao, V.V., Tewari, H.C.Deep crustal seismic studies over the Indian Shield.Glimpses of Geoscience Research in India, The Indian report to IUGS 2004-08, pp. 137-143.IndiaGeophysics - seismics
DS1999-0258
1999
Rao, Y.J.B.Gopalan, K., Kumar, A., Rao, Y.J.B.Precise 40 Ar-39 Ar age determination of the Kotakonda kimberlite and Chelima lamproite: timing of mafic dykesJournal of Geological Society India, Vol. 54, No. 2, pp. 203-4.IndiaCraton - Dhwar, Geochronology, Argon, Dike swarms - emplacement
DS1985-0555
1985
Rao, Y.V.S.Rao, Y.V.S., Murthy, I.V.R.Paleomagnetism and Ages of Dolerite Dikes in Karimnagar District, Andhra Pradesh, India.Geophys. Journal of Roy. Astron. Soc., Vol. 82, No. 2, PP. 331-India, Andhra PradeshBlank
DS1996-0289
1996
Rapalini, A.E.Conti, C.M., Rapalini, A.E., Coria, B., Koukharsky, M.Paleomagnetic evidence of an early Paleozoic rotated terrane in northwestArgentina: a clue for Gondwana.Geology, Vol. 24, No. 10, Oct. pp. 953-956ArgentinaGondwana-Laurentia, Paleomagnetics
DS1998-1209
1998
Rapalini, A.E.Rapalini, A.E.Syntectonic magnetization of the mid-Paleozoic Sierra Grande formation:further constraints on the tectonicsJournal of the Geological Society of London, Vol. 155, No. 1, Jan. pp. 105-114GlobalTectonics
DS200612-1128
2006
Rapalini, A.E.Rapalini, A.E.New late Proterozoic paleomagnetic pole for the Rio de la Plat a craton: implications for Gondwana.Precambrian Research, Vol. 147, 3-4, July 5, pp. 223-233.South America, BrazilGeochronology
DS1987-0602
1987
Rapaport, M.Rapaport, M.Why diamond dealers hate his price list- but can't live without itJewellers Circular Keystone, Vol. CLVIII, No. 12, December pp. 123-125, 128-129GlobalEconomics
DS1991-1399
1991
Rapaport, M.Rapaport, M.The impact of the global economy on diamond pricesInternational Gemological Symposium, June 20-24, 1991 Los Angeles, Gems and Gemology, Vol. 27, Spring, Program p. 9GlobalDiamond prices, Economics
DS2002-1311
2002
Rapaport, M.Rapaport, M.Diamond pricingProspectors and Developers Association of Canada (PDAC) 2002, 1p. abstractGlobalDiamond - pricing
DS201412-0723
2014
Rapaport, M.Rapaport, M.Honest grading: the truth, the whole truth and nothing but the truth.Rapaport , November 9p. AvailableGlobalDiamond industry - ethical
DS201412-0722
2014
Rapaport MagazineRapaport MagazineLucky find in Yakutia. Alrosa opens its biggest underground mine. Udachny.Rapaport , August 8, 5p.Russia, YakutiaDeposit - Udachnaya
DS201604-0590
2015
Rapatsky, V.L.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.
DS1992-0669
1992
Rapela, C.W.Harmon, R.S., Rapela, C.W.Andean magmatism and its tectonic settingGeological Society of America (GSA) Special Paper, No. 265, 350pAndes, Chile, ArgentinaMagmatism, Tectonics
DS1998-1117
1998
Rapela, C.W.Pankhurst, R.J., Rapela, C.W.The proto-Andean margin of GondwanaGeological Society of London Spec. Pub, No. 142, 336p. $ 125.00ArgentinaBook - ad, Basins - subduction
DS1998-1118
1998
Rapela, C.W.Pankhurst, R.J., Rapela, C.W.The Proto Andean margin of Gondwana: an introductionPankhurst Geological Society of London, Special Paper No. 142, pp. 1-9.ArgentinaOrogeny - Sierras Pampeanas, Gondwana - not specific to diamonds
DS1998-1210
1998
Rapela, C.W.Rapela, C.W., Pankhurst, R.J., et al.Early evolution of the Proto-Andean margin of South AmericaGeology, Vol. 26, No. 8, Aug. pp. 707-710Argentina, South America, AndesTectonics, magmatism, Gondwana, Pampean Orogeny
DS200612-1025
2006
Rapela, C.W.Pankhurst, R.J., Rapela, C.W., Fanning, C.M., Marquez, M.Gondwanide continental collision and origin of Patagonia.Earth Science Reviews, Vol. 76, 3-4, June pp. 235-257.South AmericaTectonics
DS200712-0872
2007
Rapela, C.W.Rapela, C.W., Pankhurst, R.J., Casquet, C., Fanning, C.M., Baldor Casado, E.G., Galindo, C., DahlquistThe Rio de la Plat a craton and the assembly of SW Gondwana.Earth Science Reviews, In press availableSouth America, BrazilTectonics
DS200712-0873
2007
Rapela, C.W.Rapela, C.W., Pankhurts, R.J., Casquet, C., Fanning, C.M., Baldo, E.G., Gonzalez-Casado, J.M., Galindo, C., Dahlquist, J.The Rio de la Plate craton and the assembly of SW Gondwana.Earth Science Reviews, Vol. 83, 1-2, pp. 49-82.South America, BrazilCraton, tectonics
DS1992-1253
1992
Raper, J.F.Raper, J.F., Maquire, D.J.Design models and functionality in GISComputers and Geosciences, Vol. 18, No. 4, pp. 387-394GlobalComputer, Program -Geographic information systems -design models
DS1990-1262
1990
Raphanaud, J.Roullet, G., Raphanaud, J., Legendre, J.J.A user friendly microcomputer program for modeling convex polyhedraComputers and Geosciences, Vol. 16, No. 4, pp. 461-516GlobalComputer, Program -model polyhedra
DS201212-0063
2012
Rapinesi, I.A.Bedini, A., Ehrman, S., Nunziante Cesaro, S., Pasini, M., Rapinesi, I.A., Sali, D.The Vallerano diamond from ancient Rome: a scientific study.Gems & Gemology, Vol. 48, 1, pp.TechnologyDiamond - notable
DS201212-0064
2012
Rapinesi, I.A.Bedini, A., Ehrman, S., Nunziante Cesaro, S., Pasini, M., Rapinesi, I.A., Sali, D.The Vallerano diamond from ancient Rome: a scientific study.Gems & Gemology, Vol. 48, 1, Spring pp. 39-41.GlobalHistory - diamond notable
DS1993-0446
1993
Rapolla, A.Florio, G., Fedi, M., Rapolla, A., Fountain, D.M., Shive, P.N.Anisotropic magnetic susceptibility in the continental lower crust and its implications for the shape of magnetic anomalies.Geophysical Research Letters, Vol. 20, No. 23, December 14, pp. 2623-2626.MantleGeophysics Magnetics
DS201708-1742
2017
Rapopo, M.Rapopo, M.The Liqhobong kimberlite cluster: a perspective on the distinct geology, emplacement, dilution and diamond grades for each intrusion.11th. International Kimberlite Conference, PosterAfrica, Lesothodeposit - Liqhobong
DS201708-1743
2017
Rapopo, M.Rapopo, M.The geology of the Liqhobong main pipe kimberlite.11th. International Kimberlite Conference, PosterAfrica, Lesothodeposit - Liqhobong
DS201808-1782
2018
Rapopo, M.Rapopo, M., Sobie, P.The Liqhobong kimberlite cluster: an update on the geology.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0624-5 12p.Africa, Lesothodeposit - Liqhobong

Abstract: The Cretaceous Liqhobong kimberlite cluster comprises at least six known diamondiferous Group 1 kimberlite bodies; namely the circular Main Pipe (8.5 ha), ovoid Satellite Pipe (1.6 ha), Discovery Blow (0.15 ha), Blow (0.1 ha), the Main Dike adjoining the blows and pipes, and one other recently exposed dike. The kimberlites intrude Jurassic Drakensberg lavas and outcrop at ~2650 masl in rugged Maluti Mountain terrain, and are emplaced along a strike of about 2.5km. The cluster represents at least three episodes of structurally controlled kimberlite intrusion; the first which comprised the dike(s?) and the two blows (the blows being dike enlargements emplaced 1km apart) and later the two separate emplacements of the Main and Satellite Pipes.
DS201904-0770
2019
Raposo, D.B.Raposo, D.B., Pereira, S.Y.Hydrochemistry and isotopic studies of carbonatite groundwater systems: the alkaline-carbonatite complex of Barreiro, southeastern Brazil.Environmental Earth Sciences, Vol. 78, pp. 233-South America, Brazilcarbonatite

Abstract: In Brazil, alkaline intrusions are source rocks for several commodities (bauxite, phosphate, niobium and barite, to mention a few), including mineral water. The present study aims to understand by means of chemical and stable isotope analyses, the residence time, circulation and hydrochemical facies of the groundwater systems from the alkaline-carbonatitic complex of Barreiro (State of Minas Gerais, Brazil). This Mesozoic alkaline complex is located in the Brazilian tropical region characterized by weathered soils and fractured rocks, which play an important role in the groundwater dynamics. To assess this influence, groundwater samples from 12 points and water samples from 3 artificial lakes were collected for the determination of chemical element and natural isotope (18O, deuterium and 13C) concentrations and 14C and tritium dating. Two main groundwater categories were revealed: (a) a local, acidic and sub-modern groundwater system developed in thick, poorly mineralized weathered soil from the inner part of ACCB, and (b) a basic, hypothermal, ca. 40-ky-old fractured aquifer developed in mineralized fenitized quartzites. The younger and shallower groundwater circulation is controlled by the present intrusion relief and is prone to environmental impacts. The older, hypothermal groundwater system indicates existing geothermal residual heat provided by the Mesozoic alkaline intrusion.
DS200412-0396
2004
Raposo, M.I.D'Agreela Filho, M.S., Pacca, II., Trinidade, R.I., Teixeira, W., Raposo, M.I., Onstott, T.C.Paleomagnetism and 40 Ar 39 Ar ages of mafic dikes from Salvador ( Brazil): new constraints on the Sao Francisco craton APW pathPrecambrian Research, Vol. 132, 1-2, pp. 55-77.South America, BrazilGeochronology
DS200412-1625
2004
Raposo, M.I.Raposo, M.I., Chaves, A.O., Lojkasek Lima, P., D'Agrella Filho, M.S., Teixeira, W.Magnetic fabrics and rock magnetism of Proterozoic dike swarm from the southern Sao Francisco Craton, Minas Gerais, Brazil.Tectonophysics, Vol. 378, 1-2, pp. 43-63.South America, Brazil, Minas GeraisGeophysics - magnetics
DS200712-0874
2007
Raposo, M.I.Raposo, M.I., D'Agrella Filho, M.S., Pinese, J.P.Magnetic fabrics and rock magnetism of Archean and Proterozoic dike swarms in the Sao Francisco craton, Brazil.Tectonophysics, Vol. 443, 1-2, pp. 53-71.South America, BrazilDike Swarms
DS1995-1546
1995
Raposo, M.I.B.Raposo, M.I.B., Ernesto, M.An early Cretaceous paleomagnetic pole from Ponta Grossa dikes-implications Mesozoic Polar wander pathJournal of Geophysical Research, Vol. 100, No. NB10, Oct, pp. 95-109BrazilGeophysics -paleomagnetics
DS200512-1063
2005
RappSueda, Y., Irifune, T., Nishiyama, N., Rapp, Ferroir, Onozawa, Yagi, Merkel, Miyajima, FunakoshiA new high pressure form of K Al Si3 08 under lower mantle conditions.Geophysical Research Letters, Vol. 31, 23, Dec. 16, DOI 10.1029/2004 GLO21156MantleUHP
DS1990-1237
1990
Rapp, G.R. Jr.Roberts, W.L., Campbell, T.J., Rapp, G.R. Jr.Encyclopedia of minerals ( second edition)Van Nostrand, 979p. approx. $ 140.00GlobalMineralogy, Book review
DS201605-0886
2016
Rapp, R.Rapp, R.Sediment derived fluid metasomatism in the subcratonic lithospheric mantle and the origin of diamonds.DCO Edmonton Diamond Workshop, June 8-10MantleDiamond genesis
DS1990-1216
1990
Rapp, R.P.Rapp, R.P.Vapor-absent partial melting of amphibolite/eclogite at 8-32 Kbar; implications for the origin and growth of the continental crustPh.D. Thesis, Rensselaer Polytechnic Institute, Troy NY, 327pGlobalEclogite, Crust
DS1995-1547
1995
Rapp, R.P.Rapp, R.P.Is eclogite in the sub-continental lithosphere the residue from melting of subducted crust? Experimental..Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 457-459.Russia, SiberiaEclogites, Deposit -Udachnaya
DS1995-1548
1995
Rapp, R.P.Rapp, R.P., Watson, K.B.Dehydration melting of metabasalt at 8-32kbar: implic- ations for continental growth and crust-mantle recycleJournal of Petrology, Vol. 96, No. 4, pp. 891-931MantleMelt, Recycling, Mantle-crust
DS1998-1211
1998
Rapp, R.P.Rapp, R.P., Shimizu, N.The nature of subduction derived metasomatism in the upper mantle:dehydration melting of hydrous basalt.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1237-8.MantleSubduction, Lawsonite, phengite
DS1999-0581
1999
Rapp, R.P.Rapp, R.P., Shimizu, N., Applegate, G.S.Reaction between slab derived melts and peridotite in the mantle wedge:experimental constraints at 3.8 GPaChemical Geology, Vol. 160, No. 4, Sept. 2, pp. 335-56.MantlePeridotite - melting, Slab
DS2000-1002
2000
Rapp, R.P.Wang, W., Gasparik, T., Rapp, R.P.Partitioning of rare earth elements between CaSiO3 perovskite and co-existing phases: inclusions diamondsEarth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.291-300.GlobalDiamond - inclusions, genesis, Subduction
DS2003-1129
2003
Rapp, R.P.Rapp, R.P., Shimizu, N.On the origin of eclogite and websterite parageneses in the cratonic mantle, and their8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractMantleEclogites, diamonds, Craton, magmatism
DS2003-1130
2003
Rapp, R.P.Rapp, R.P., Shimizu, N., Norman, M.D.Growth of early continental crust by partial melting of eclogiteNature, No. 6958, Oct. 9, pp. 605-8.MantleEclogite - subduction
DS2003-1510
2003
Rapp, R.P.Xu, J.F., Shinjo, R., Defant, M.J., Wang, Q., Rapp, R.P.Origin of Mesozoic adakitic intrusive rocks in the Nigzhen area of east China: partialGeology, Vol. 30, 12, Dec.pp. 111-1114.ChinaMelting, mantle, slab
DS200412-1626
2004
Rapp, R.P.Rapp, R.P., Irifune, T., Shimizu, N.Recycling of continental sediments into the deep mantle: experimental constraints at 15-25 GPa.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A561.MantleSubduction
DS200412-1627
2003
Rapp, R.P.Rapp, R.P., Shimizu, N.On the origin of eclogite and websterite parageneses in the cratonic mantle, and their relationship to TTG granitoid magmatism.8 IKC Program, Session 2, AbstractMantleEclogite, diamonds Craton, magmatism
DS200412-1628
2003
Rapp, R.P.Rapp, R.P., Shimizu, N., Norman, M.D.Growth of early continental crust by partial melting of eclogite.Nature, No. 6958, Oct. 9, pp. 605-8.MantleEclogite - subduction
DS200512-0890
2005
Rapp, R.P.Rapp, R.P.Subduction origin for Earth's earliest continental fragments: experimental constraints on Archean granitoid petrogenesis, evolution continental lithospheGAC Annual Meeting Halifax May 15-19, Abstract 1p.MantleSubduction
DS200812-0363
2008
Rapp, R.P.Foley, S.F., Yaxley, G.M., Rosenthal, A., Rapp, R.P., Jacob, D.E.Experimental melting of peridotites in the presence of CO2 and H2O at 40 - 60 kbar.9IKC.com, 3p. extended abstractTechnologyPeridotite - melting
DS200812-0939
2008
Rapp, R.P.Rapp, R.P., Irifune, T., Shimizu, N., Nishiyama, N., Norman, M.D., Inoue, T.Subduction recycling of continental sediments and the origin of geochemically enriched reservoirs in the deep mantle.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 14-23.MantleSubduction
DS201012-0205
2009
Rapp, R.P.Foley, S.F., Yaxley, G.M., Rosenthal, A., Buhre, S., Kisseeva, E.S., Rapp, R.P., Jacob, D.E.The composition of near solidus melts of peridotite in the presence of CO2 and H2O between 40 and 60 kbar.Lithos, Vol. 112 S pp. 274-283.MantleMineral chemistry
DS201012-0611
2010
Rapp, R.P.Rapp, R.P., Norman, M.D., Laporte, D., Yaxley, G.M., Martin, H., Foley, S.F.Continent formation in the Archean and chemical evolution of the cratonic lithosphere: melt rock reaction experiments at 3-4 GPa and petrogenesisJournal of Petrology, Vol. 51, 6, pp. 1237-1266.MantleSanukitoids
DS201412-0617
2014
Rapp, R.P.Nebel, O., Rapp, R.P., Yaxley, G.M.The role of detrital zircons in Hadean crustal research.Lithos, Vol. 190-191, pp. 313-327.MantleGeochronology
DS201708-1744
2017
Rapp, R.P.Rapp, R.P.Metasomatism of cratonic lithosphere by hydrous, silica-rich, fluids derived from recycled sediment: experimental insights at 5-7GPa.11th. International Kimberlite Conference, OralTechnologymetasomatism
DS1998-1212
1998
Rapp. R.P.Rapp. R.P., Shimizu, N.Subduction and slab melting in the Archean: experimental constraints And implications for craton..7th. Kimberlite Conference abstract, pp. 720-22.South Africa, Siberia, West AfricaCraton - Kaapvaal, Subsduction, tectonics
DS1999-0582
1999
RappaportRappaportSelling the diamond dream... brief interview with S. Lussier world wide director of de Beers consumer marketRapaport, Gemological Institute of America (GIA) spec. edition, June, p. 1-9.GlobalDiamond - sales
DS201911-2543
2019
Rappirich, V.Magna, T., Viladkar, S., Rappirich, V., Pour, O., Cejkova, B.Nb-V enriched sovites of the northeastern and eastern part of the Amba Dongar carbonatite ring dike, India - a reflection of post emplacement hydrothermal overprint.Chemie der Erde, in press available 11p. Indiadeposit - Amba Dongar
DS201707-1300
2017
Rapprich, V.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.
DS201709-1976
2017
Rapprich, V.Czupponi, G., Magna, T., Benk, Z., Rapprich, V., Ott, U.Noble gases in Indian carbonatites.Goldschmidt Conference, abstract 1p.Indiacarbonatites

Abstract: We have studied noble gases in carbonates and apatites from three carbonatites of South India, namely Hogenakal (2400 Ma), Sevattur (770 Ma) and Khambamettuu (523 Ma) by vacuum crushing. Apatite has also been analysed by pyrolysis. Vacuum crushing mostly releases the trapped gas components. The ratios 21Ne/20Ne, 22Ne/20Ne and 40Ar/36Ar increase with progressive crushing due to preservation of different composition gases in smaller inclusions released in later steps. This heterogeneity of isotopic composition of fluid inclusions is a consequence of the involvement of magmas carrying different noble gas signatures. The inclusions with lower ratios suggest the presence of a subducted atmospheric component, while the higher 21Ne/20Ne, 22Ne/20Ne and 40Ar/36Ar can be attributed to the presence of an enriched lithospheric mantle component. In addition, very minor trapped gases from less degassed, deeper mantle may also be present but overprinted by lithospheric and/or nucleogenic components. We propose that these carbonatites were generated only in an advanced stage of magmatism when this lithospheric component overwhelmed any contribution from the deeper mantle source. The lithospheric mantle underwent enrichment during an ancient subduction process through mantle metasomatism manifested in nucleogenic/radiogenic isotopic ratios of 21Ne/20Ne, 22Ne/20Ne and 40Ar/36Ar. The apatites analysed by pyrolysis clearly show nucleogenic 21Ne from 18O(?,n) reaction. We have demonstrated the potential of using U,Th–21Ne systematics as a thermo-chronometer in conjunction with the established U,Th–4He and U–136Xe clocks. While for Hogenakal, the U,Th–21Ne age of 845 ± 127 Ma is in agreement with the age of emplacement of other adjacent younger carbonatites, syenites and alkali granites, for the Sevattur apatite (738 ± 111 Ma) it indicates the crystallisation age.
DS201709-2025
2017
Rapprich, V.Magalhaes, N., Magna, T., Rapprich, V., Kratky, O., Farquhar, J.Sulfur isotope systematics in carbonatites from Sevattur and Samalpatti, S India.Goldschmidt Conference, abstract 1p.Indiacarbonatites, Sevattur, Samalpatti

Abstract: We report preliminary data for sulfur isotopes from two spatially related Neoproterozoic carbonatite complexes in Tamil Nadu, S India, with the aim of getting further insights into their magmatic and/or post-emplacement histories [1]. The major sulfide phase in these rocks is pyrite, with minor chalcopyrite, whereas sulfate occurs as barite. A bimodal distribution of G34Ssulfide is found for Samalpatti (13.5 to 14.0‰), and Sevattur (?2.1 to 1.4‰) carbonatites. A significantly larger range of G34Ssulfide values is found for the associated Samalpatti silicate rocks (?5.2 to 7.4‰) relative to Sevattur pyroxenites and gabbros (?1.1 to 2.1‰). High G34Ssulfide values for Samalpatti carbonatites are unsual [2,3] but could reflect hydrothermal post-emplacement modification [1] of S isotopes. The low G34Ssulfide values for Sevattur may represent a mantle source signature. The G34Ssulfate is uniformly positive for both complexes, with most data falling in a narrow range (5.7 to 7.8‰) and one datum for a pyroxenite yielding more positive G34Ssulfate = 13.3‰. Data for '33S varies outside of analytical uncertainty (?0.07 to 0.04‰), indicating contribution from a source with a surface-derrived component. The small range of '33S values does not allow us to determine whether these sources contain S fractionated by biogeochemical (mass-dependent) or photochemical (mass-independent, pre GOE) processes. Data for '36S is positive, and varies within uncertainty (0.28 ± 0.15‰). Variations of this magnitude have been observed in other localities, and are not diagnostic of any unique source or process. The sulfur isotope data imply addition of crustal sulfur to Samalpatti. In contrast, sulfur from Sevattur has a mantle-like G34S but '33S with anomalous character. These observations support the idea of a different evolutionary story for these complexes, possibly more complex than previously thought.
DS201709-2026
2017
Rapprich, V.Magna, T., Wittke, A., Gussone, N., Rapprich, V., Upadhyay, D.Calcium isotope composition of carbonatites - a case study of Sevattur and Samalpatti, S. India.Goldschmidt Conference, abstract 1p.Indiacarbonatites

Abstract: Calcium isotope compositions are presented for two suites of carbonatites and associated alkaline silicate rocks from Neoproterozoic Sevattur and Samalpatti complexes in Tamil Nadu, South India. Despite their geographic proximity, the mean G44/40Ca values are different for Sevattur (G44/40Ca = 0.69 r 0.10‰, n = 7) and Samalpatti (0.81 r 0.16‰, n = 5). The former suite is derived from an enriched mantle source without significant post-emplacement modifications [1] and its Ca isotope composition falls to the lower end of Ca isotope range reported for mantle-derived rocks [2]. Some carbonatites from Samalpatti show a 44Ca-enriched signature which could reflect large-scale low-temperature modification, recognized also by their 13C–18O-enriched isotope systematics and sizeable loss of REE, when compared to pristine carbonatites from the area [1]. This is also consistent with albite–epidote metasomatic sample and shistose pyroxenite from Samalpatti, both showing a 44Ca-depleted signature. Leaching experiments confirm a systematic G44/40Ca offset with isotopically light carbonate relative to bulk sample [also 3]. Pyroxenites from Samalpatti are isotopically heavier than accompanying unmodified carbonatites and their G44/40Ca values fall into the mantle range. In contrast, pyroxenite and phosphate from Sevattur have a G44/40Ca value identical with associated carbonatites, indicating a homogeneous mantle source for the latter complex. For K-rich syenites and monzonites, 40K-decay corrections need to be considered for the intrinsic mass-dependent isotope fractionations considering the Neoproterozoic age and high K/Ca character of some samples.
DS201709-2047
2017
Rapprich, V.Rapprich, V., Pecskay, Z., Magna, T., Mikova, J.Age disparity for spatially related Sevattur and Samalpatti carbonatite complexes.Goldschmidt Conference, abstract 1p.Indiacarbonatites

Abstract: The Neoproterozoic Sevattur and Samalpatti alkaline– carbonatite complexes in S India were supposedly emplaced into regional metagranite at ~800 Ma [1]. Both complexes are close to each other (~4 km apart), with a similar NE–SW elongated oval shape arranged along NE–SW trending lineament formed by the Koratti–Attur tectonic zone [2]. Both complexes share a similar setting with central syenite intrusion mantled with a discontinuous ring and/or crescentshaped suites of carbonatites, pyroxenites, gabbros, and dunites. In contrast to identical tectonic position and similar structure, the two complexes differ significantly in geochemistry and Sr–Nd–Pb–O–C isotope compositions. The Sevattur suite is derived from an enriched mantle source without significant post-emplacement modification whilst extensive hydrothermal overprint by crustal fluids must have occurred to result in the observed 13C–18O-enriched systematics reported for the Samalpatti carbonatites [3]. Some Samalpatti pyroxenites, though, show a clear mantle signature [3]. We report preliminary K–Ar age-data, that indicate a prolonged period of the magmatic activity in this area. Sevattur gabbro and pyroxenite (both Bt-fraction) as well as one Samalpatti Cr-rich silicocarbonatite (Amp-fraction) yielded the range of ages at 700–800 Ma, consistent with previous reports [see 3 for details]. The new K–Ar data from syenites display significantly younger ages of 560–576 Ma for Samalpatti and 510–540 Ma for Sevattur, regardless of the mineral fraction used (Bt or Kfs). The K–Ar results are being supplemented by systematic U–Pb analyses of zircons. If proven true, the age disparity would have profound consequences on our understanding of carbonatite evolution.
DS201710-2209
2017
Rapprich, V.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
Rapprich, V.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.
DS201801-0035
2017
Rapprich, V.Magna, T., Rapprich, V., Wittke, A., Gussone, N., Upadhyay, D., Mikova, J., Pecskay, Z.Calcium isotope systematics and K-Ar and U-Pb temporal constraints on the genesis of Sevattur Samalpatti carbonatite silicate alkaline complexes.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 34-35.Indiadeposit - Samalpatti, Sevattur

Abstract: We present the first systematic survey of Ca isotope compositions in carbonatites and associated silicate rocks from Samalpatti and Sevattur, two Neoproterozoic complexes in Tamil Nadu, south India. Despite their close geographic proximity, their genesis and post-emplacement histories differ (Ackerman et al. 2017). The Sevattur complex appears to have been derived from an enriched mantle source with a limited post-magmatic disturbance. In contrast, carbonatites from Samalpatti show a record of extensive late-stage post-magmatic overprint, also apparent from unusually heavy C-O isotope compositions in a sub-suite of carbonatites (Ackerman et al. 2017). The mean ?44/40Ca = 0.69 ± 0.10‰ is slightly lighter than the average of fertile, unmetasomatized peridotites at ?44/40Ca = 0.95 ± 0.05‰ (Kang et al. 2017). This difference may attest to the general difference between carbonates and silicates (see Kang et al. 2017). It could also reflect Ca isotope fractionation between isotopically heavy silicate and isotopically light carbonate (e.g., John et al. 2012), though to a somewhat minor extent. This is supported by leaching experiments in this study where the extent of silicate-carbonate fractionation (44/40Casilicate-carbonate) has been investigated. The values at ~0.1-0.2‰ are expectedly lower than those reported earlier (~0.6‰; John et al. 2012) and may reflect high-temperature Ca isotope fractionation. The variability in ?44/40Ca values of carbonatites and silico-carbonatites from the Samalpatti complex is larger (0.70- 1.14‰) and appears to be in accord with extensive post-emplacement disturbance. Significant loss of REE and 13C-18O-enriched signature are combined with high ?44/40Ca values, which could reflect massive exchange with metasomatic aqueous fluids. The 40Kdecay correction was applied to K-rich rocks (syenites, monzonites). Given the antiquity of the complex dated at ca. ~800 Ma (Schleicher et al. 1997) and considering high-K/Ca character of some rocks, the resulting ?44/40Ca800 Myr correction was up to ~+1.2‰. In this regard, it is crucial to constrain the age history of the entire region. The nearby Hogenakal carbonatite body was dated at ~2.4 Ga which is much older than Rb-Sr and Sm-Nd age of Sevattur (Kumar et al. 1998) from the same fault system. We have acquired K-Ar mineral (K-feldspar, biotite, amphibole) and U-Pb zircon data from Sevattur and Samalpatti. The K-Ar ages span a range between ~800 and ~510 Ma (~800 Ma for amphiboles and biotites from silico-carbonatites and mafic silicate rocks and ~570-510 Ma for K-feldspars and biotites from syenites), dating two high-grade regional tectono-thermal overprint events, documented earlier. The complex nature of this process is indicated by concordant U-Pb zircon age at ~2.5 Ga yielded for a melatonalite, for which K-Ar biotite age of ~802 Ma was measured. This fits into the age bracket of basement of the Eastern Dharwar Craton. The age distribution bimodality at ~2.5 Ga and ~800 Ma has been found for several other samples, suggesting a pulsed thermal history of the area, associated with a significant overprint by fluids likely derived from the local crust. Particularly high U concentrations in zircons (thousands ppm), combined with a range of K-Ar ages, attest to such multi-episodic history.
DS201801-0048
2017
Rapprich, V.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
Rapprich, V.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.
DS202102-0204
2020
Rapprich, V.Magna, T., Viladar, S., Rapprich, V., Pour, O., Hopp, J., Cejkova, B.Nb-V enriched sovites of the northeastern and eastern part of the Amba Dongar carbonatite ring dike, India - a reflection of post-emplacement hydrothermal overprint?Geochemistry, Vol. 80, doi.org/10.1016 /j.chemer.2019 .125534 11p. PdfIndiadeposit - Amba Dongar

Abstract: Wakefieldite-(Ce,La) and vanadinite in coarse-grained calciocarbonatites (sovites) are for the first time reported from the northeastern part of the worldwide largest fluorite deposit at the Amba Dongar carbonatite ring dike, India. Sovite in this part of the carbonatite ring dike is rich in pyrochlore, calcite and magnetite. Pyrochlore makes up almost 50% of some sovite samples and shows core-to-rim compositional changes. The core of pyrochlore consists of primary fluorcalciopyrochlore with high F and Na contents while the margins gained elevated amounts of Pb, La and Ce with the associated loss of F and Na due to circulation of hydrothermal solutions. The presence of wakefieldite-(Ce,La) and vanadinite points to an exceptionally high V abundance in hydrothermal solutions formed towards the end of the carbonatite magma activity. This investigation thus opens new promising areas for Nb and REE prospection in the eastern part of the Amba Dongar carbonatite body.
DS1960-0733
1966
Rapson, J.E.Rapson, J.E.Carbonatite in the Alkaline Complex of the Ice River Area, Southern Canadian Rocky Mountains.Fourth International Min. Association Meeting Publishing Min. Soc. of India., PP. 9-22.Canada, British ColumbiaRelated Rocks
DS200812-0764
2008
Raquin, A.Moreira, M., Raquin, A.Are noble gases subducted in the deep mantle?Goldschmidt Conference 2008, Abstract p.A649.MantleSubduction
DS201212-0498
2012
Raquin, A.Mourao, C., Moreira, M., Mata, J., Raquin, A., Madeira, J.Primary and secondary processes constraining the noble gas isotopic signatures of carbonatites and silicate rocks from Brava Island: evidence for a lower mantle origin of the Cape Verde Plume.Contributions to Mineralogy and Petrology, Vol. 163, 6, pp. 995-1009.Europe, Brava IslandCarbonatite
DS1989-1541
1989
rare earth elements (REE), F.H.Vanthiel, M., rare earth elements (REE), F.H.Theoretical description of the graphite, diamond and liquid phases ofcarbonInternational Journal of TherM., Vol. 10, No. 1, January pp. 227-236GlobalExperimental petrology, Carbon
DS2001-0083
2001
Rasamimana, G.Bardintzeff, J.M., Bonin, B., Rasamimana, G.The Cretaceous Morondava volcanic province: mineralogical, petrological and geochemical aspects.Journal of African Earth Sciences, Vol. 32, No. 2, pp. 299-316.MadagascarBasalts - Ti-P olivines
DS201012-0037
2010
Rasamimana, G.Bardintzeff, J-M., Ligeois, J-P., Bonin, B., Bellon, H., Rasamimana, G.Madagascar volcanic provinces linked to the Gondwana break-up: geochemical isotopic evidences for contrasting mantle sources.Gondwana Research, Vol. 18, 2-3, pp. 295-314.Africa, MadagascarGeochronology
DS1998-1213
1998
Rasamimanana, G.Rasamimanana, G., et al.Rifting related magmatic episodes of south western Malagasy Morondavabasin.IN FRENCHC.r. Academy Of Science Paris, Vol. 326, pp. 685-91.GlobalTectonics
DS1990-1217
1990
Rasanen, M.E.Rasanen, M.E., Salo, S., Jungnert, H., Pittman, L.R.Evolution of the Western Amazon Lowland relief: impact of Andean forelanddynamicsTerra Nova, Vol. 2, pp. 320-332Brazil, AndesTectonics, Geomorphology
DS201612-2303
2016
Rasbury, E.T.Hulett, S.R.W., Simonetti, A., Rasbury, E.T., Hemming, N.G.Recyclying of subducted crustal components into carbonatite melts revealed by boron isotopes.Nature Geoscience, Nov. 7, on line 6p.GlobalCarbonatite

Abstract: The global boron geochemical cycle is closely linked to recycling of geologic material via subduction processes that have occurred over billions of years of Earth’s history. The origin of carbonatites, unique melts derived from carbon-rich and carbonate-rich regions of the upper mantle, has been linked to a variety of mantle-related processes, including subduction and plume-lithosphere interaction. Here we present boron isotope (?11B) compositions for carbonatites from locations worldwide that span a wide range of emplacement ages (between ~40 and ~2,600?Ma). Hence, they provide insight into the temporal evolution of their mantle sources for ~2.6 billion years of Earth’s history. Boron isotope values are highly variable and range between ?8.6 and +5.5, with all of the young (<300?Ma) carbonatites characterized by more positive ?11B values (>?4.0‰ whereas most of the older carbonatite samples record lower B isotope values. Given the ?11B value for asthenospheric mantle of ?7 ± 1‰ the B isotope compositions for young carbonatites require the involvement of an enriched (crustal) component. Recycled crustal components may be sampled by carbonatite melts associated with mantle plume activity coincident with major tectonic events, and linked to past episodes of significant subduction associated with supercontinent formation.
DS201701-0015
2016
Rasbury, E.T.Hulett, S.R.W., Simonetti, A., Rasbury, E.T., Hemming, G.Recycling of subducted crustal components into carbonatite melts revealed by boron isotopes.Nature Geoscience, Vol. 9, pp. 904-908.MantleMagmatism

Abstract: The global boron geochemical cycle is closely linked to recycling of geologic material via subduction processes that have occurred over billions of years of Earth’s history. The origin of carbonatites, unique melts derived from carbon-rich and carbonate-rich regions of the upper mantle, has been linked to a variety of mantle-related processes, including subduction and plume-lithosphere interaction. Here we present boron isotope (?11B) compositions for carbonatites from locations worldwide that span a wide range of emplacement ages (between ~40 and ~2,600?Ma). Hence, they provide insight into the temporal evolution of their mantle sources for ~2.6 billion years of Earth’s history. Boron isotope values are highly variable and range between ?8.6‰ and +5.5‰, with all of the young (<300?Ma) carbonatites characterized by more positive ?11B values (>?4.0‰), whereas most of the older carbonatite samples record lower B isotope values. Given the ?11B value for asthenospheric mantle of ?7 ± 1‰, the B isotope compositions for young carbonatites require the involvement of an enriched (crustal) component. Recycled crustal components may be sampled by carbonatite melts associated with mantle plume activity coincident with major tectonic events, and linked to past episodes of significant subduction associated with supercontinent formation.
DS1992-1254
1992
Rashad, M.Z.Rashad, M.Z.Selection of suitable sample size for ore evaluationAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, Annual Meeting held Phoenix Arizona Feb. 24-27th. 1992, Preprint No. 92-33, 4pGlobalGeostatistics, ore reserves, Ore evaluation
DS201412-0308
2014
Rashchenko, S.V.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
DS201712-2706
2017
Rashchenko, S.V.Mikhno, A.O., Musiyachenko, K.A., Shcheptova, O.V., Koraskov, A.V., Rashchenko, S.V.CO2 bearing fluid inclusions associated with diamonds in zircon from the UHP Kokchetav gneisses.Journal of Raman Spectroscopy, Vol. 48, 11, pp. 1566-1573.RussiaUHP - Kokchetav

Abstract: CO2-bearing fluid inclusions coexisting with diamonds were identified in zircons from diamondiferous gneiss in the Kokchetav Massif. This discovery provides evidence for the presence of CO2 in UHP fluids and diamond formation in moderately oxidized conditions in the Kokchetav gneiss. Fluid and multiphase solid inclusions coexisting in zircons represent immiscible melt and fluid captured close to the peak metamorphic conditions for the Kokchetav UHP gneiss. Most of CO2-bearing inclusions are CO2+H2O mixtures except for some cases when they also contain daughter phases (e.g. muscovite, calcite and quartz) tracing the presence of aqueous and solute-rich fluids at different phases of UHP metamorphism. Decrease of pressure and temperature may have been responsible for the reduction of solutes in the CO2-bearing fluid. The lack of CO2-bearing inclusions in garnet porphyroblasts from diamond-bearing gneiss, as well as the common coexistence of aqueous CO2-bearing inclusions with calcite, testify that most likely all CO2 in fluid was consumed by the calcite-forming reaction and hydrous melt was the only remaining growth medium during retrograde metamorphism of the Kokchetav UHPM gneisses. Neither K-cymrite nor kokchetavite was identified among daughter phases in the hydrous melt inclusions in garnet, which indicates that they hardly could originate in a metapelitic system.
DS200512-0231
2005
Raskazov, S.V.Demonterova, E.I., Ivanov, A.V., Raskazov, S.V.Inverse trace element modeling of mantle components from Late Cenozoic basalts in Central Asia.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantle, AsiaMantle plume, geochronology
DS1960-1197
1969
Rasky, F.Rasky, F.The Hush Hush Diamond Hunt in Darkest Northern OntarioStar Weekly, APRIL 5TH.Canada, Ontario, Kirkland LakeProspecting, History
DS2002-0361
2002
Rasmussen, B.Dawson, G.C., Krapez, B., Fletcher, I.R., McNaughton, N.J., Rasmussen, B.Did late Paleoproterozoic assembly of proto Australia involve collision between thePrecambrian Research, Vol. 118, No. 3-4, pp. 195-220.Australia, Western AustraliaTectonics, Orogeny - Albany - Fraser
DS2003-0321
2003
Rasmussen, B.Dawson, G.C., Krapez, B., Fletcher, I.R., McNaughton, N.J., Rasmussen, B.1.2 Ga thermal metamorphism in the Albany Fraser Orogen of western Australia:Journal of the Geological Society of London, Vol. 160, 1, pp. 29-38.AustraliaGeothermometry
DS200412-1629
2004
Rasmussen, B.Rasmussen, B., Fletcher, I.R.Zirconolite: a new U Pb chronometer for mafic igneous rocks.Geology, Vol. 32, 9, pp. 785-788.TechnologyGeochronology - not specific to diamonds
DS201704-0634
2017
Rasmussen, B.Korhonen, F.J., Johnson, S.P., Wingate, M.T.D., Fletcher, I.R., Dunkley, D.J., Roberts, M.P., Sheppard, S., Muhling, J.R., Rasmussen, B.Radiogenic heating and craton-margin plate stresses as drivers for intraplate orogeny.Journal of Metamorphic Geology, in press availableMantleCraton

Abstract: The Proterozoic belts that occur along the margins of the West Australian Craton, as well as those in intraplate settings, generally share similar geological histories that suggest a common plate-margin driver for orogeny. However, the thermal drivers for intraplate orogenesis are generally more poorly understood. The Mutherbukin Tectonic Event records a protracted period of Mesoproterozoic reworking of the Capricorn Orogen and offers significant insight into both the tectonic drivers and heat sources of long-lived intraplate orogens. Mineral assemblages and tectonic fabrics related to this event occur within a 50 km-wide fault-bound corridor in the central part of the Gascoyne Province in Western Australia. This zone preserves a crustal profile, with greenschist facies rocks in the north grading to upper amphibolite facies rocks in the south. The P- T-t evolution of 13 samples from 10 localities across the Mutherbukin Zone is investigated using phase equilibria modelling integrated with in situ U-Pb monazite and zircon geochronology. Garnet chemistry from selected samples is used to further refine the P-T history and shows that the dominant events recorded in this zone are prolonged D1 transpression between c. 1320 and 1270 Ma, followed by D2 transtension from c. 1210 to 1170 Ma. Peak metamorphic conditions in the mid-crust reached >650 °C and 4.4-7 kbar at c. 1210-1200 Ma. Most samples record a single clockwise P-T evolution during this event, although some samples might have experienced multiple perturbations. The heat source for metamorphism was primarily conductive heating of radiogenic mid- and upper crust, derived from earlier crustal differentiation events. This crust was thickened during D1 transpression, although the thermal effects persisted longer than the deformation event. Peak metamorphism was terminated by D2 transtension at c. 1210 Ma, with subsequent cooling driven by thinning of the radiogenic crust. The coincidence of a sedimentary basin acting as a thermal lid and a highly radiogenic mid-crustal batholith restricted to the Mutherbukin Zone accounts for reworking being confined to a discrete crustal corridor. Our results show that radiogenic regions in the shallow to mid crust can elevate the thermal gradient and localize deformation, causing the crust to be more responsive to far-field stresses. The Mutherbukin Tectonic Event in the Capricorn Orogen was synchronous with numerous Mesoproterozoic events around the West Australian Craton, suggesting that thick cratonic roots play an important role in propagating stresses generated at distant plate boundaries.
DS201706-1115
2017
Rasmussen, B.Zi, J-W., Gregory, C.J., Rasmussen, B., Sheppard, S., Muhling, J.R.Using monazite geochronology to test the plume model for carbonatites: the example of Gifford Creek carbonatite complex, Australia.Chemical Geology, Vol. 463, pp. 50-60.Australiacarbonatite

Abstract: Carbonatites are carbonate-dominated igneous rocks derived by low-degree partial melting of metasomatized mantle, although the geodynamic processes responsible for their emplacement into the crust are disputed. Current models favor either reactivation of lithospheric structures in response to plate movements, or the impingement of mantle plumes. Geochronology provides a means of testing these models, but constraining the age of carbonatites and related metasomatic events is rarely straightforward. We use in situ U-Th-Pb analysis of monazite by SHRIMP to constrain the emplacement age and hydrothermal history of the rare earth element-bearing Gifford Creek Carbonatite Complex in Western Australia, which has been linked to plume magmatism at ca. 1075 Ma. Monazite in carbonatites and related metasomatic rocks (fenites) from the carbonatite complex dates the initial emplacement of the carbonatite at 1361 ± 10 Ma (n = 22, MSWD = 0.91). The complex was subjected to multiple stages of magmatic/hydrothermal overprinting from ca. 1300 Ma to 900 Ma during later regional tectonothermal events. Carbonatite emplacement at ca. 1360 Ma appears to be an isolated igneous event in the region, and occurred about 300 million years before intrusion of the ca. 1075 Ma Warakurna large igneous province, thus precluding a genetic connection. The Gifford Creek Carbonatite Complex occurs within a major crustal suture, and probably formed in response to reactivation of this suture during plate reorganization. Our study demonstrates the veracity of monazite geochronology in determining the magmatic and hydrothermal histories of a carbonatite complex, critical for evaluating competing geodynamic models for carbonatites. The approach involving in situ SHRIMP U-Th-Pb dating of monazite from a wide spectrum of rocks in a carbonatite complex is best suited to establishing the intrusive age and hydrothermal history of carbonatites.
DS201708-1587
2017
Rasmussen, B.Zi, J-W., Gregory, C.J., Rasmussen, B., Sheppard, S., Muhling, J.R.Using monazite geochronology to test the plume model for carbonatites: the example of Gifford Creek carbonatite complex, Australia.Chemical Geology, Vol. 463, pp. 50-60.Australiacarbonatites, Gifford Creek

Abstract: Carbonatites are carbonate-dominated igneous rocks derived by low-degree partial melting of metasomatized mantle, although the geodynamic processes responsible for their emplacement into the crust are disputed. Current models favor either reactivation of lithospheric structures in response to plate movements, or the impingement of mantle plumes. Geochronology provides a means of testing these models, but constraining the age of carbonatites and related metasomatic events is rarely straightforward. We use in situ U-Th-Pb analysis of monazite by SHRIMP to constrain the emplacement age and hydrothermal history of the rare earth element-bearing Gifford Creek Carbonatite Complex in Western Australia, which has been linked to plume magmatism at ca. 1075 Ma. Monazite in carbonatites and related metasomatic rocks (fenites) from the carbonatite complex dates the initial emplacement of the carbonatite at 1361 ± 10 Ma (n = 22, MSWD = 0.91). The complex was subjected to multiple stages of magmatic/hydrothermal overprinting from ca. 1300 Ma to 900 Ma during later regional tectonothermal events. Carbonatite emplacement at ca. 1360 Ma appears to be an isolated igneous event in the region, and occurred about 300 million years before intrusion of the ca. 1075 Ma Warakurna large igneous province, thus precluding a genetic connection. The Gifford Creek Carbonatite Complex occurs within a major crustal suture, and probably formed in response to reactivation of this suture during plate reorganization. Our study demonstrates the veracity of monazite geochronology in determining the magmatic and hydrothermal histories of a carbonatite complex, critical for evaluating competing geodynamic models for carbonatites. The approach involving in situ SHRIMP U-Th-Pb dating of monazite from a wide spectrum of rocks in a carbonatite complex is best suited to establishing the intrusive age and hydrothermal history of carbonatites.
DS201709-2019
2017
Rasmussen, B.Kohonen, F.J., Johnson, S.P., Wingate, M.T.D., Kirkland, C.L., Fletcher, I.R., Dunkley, D.J., Roberts, M.P., Sheppard, S., Muhling, J.R., Rasmussen, B.Radiogenic heating and craton margin plate stresses as drivers for intraplate orogeny.Journal of Metamorphic Geology, Vol. 35, 6, pp. 631-661.Mantlegeothermometry

Abstract: The Proterozoic belts that occur along the margins of the West Australian Craton, as well as those in intraplate settings, generally share similar geological histories that suggest a common plate-margin driver for orogeny. However, the thermal drivers for intraplate orogenesis are more poorly understood. The Mutherbukin Tectonic Event records a protracted period of Mesoproterozoic reworking of the Capricorn Orogen and offers significant insight into both the tectonic drivers and heat sources of long-lived intraplate orogens. Mineral assemblages and tectonic fabrics related to this event occur within a 50 km-wide fault-bound corridor in the central part of the Gascoyne Province in Western Australia. This zone preserves a crustal profile, with greenschist facies rocks in the north grading to upper amphibolite facies rocks in the south. The P–T–t evolution of 13 samples from 10 localities across the Mutherbukin Zone is investigated using phase equilibria modelling integrated with in situ U–Pb monazite and zircon geochronology. Garnet chemistry from selected samples is used to further refine the P–T history and shows that the dominant events recorded in this zone are prolonged D1 transpression between c. 1,320 and 1,270 Ma, followed by D2 transtension from c. 1,210 to 1,170 Ma. Peak metamorphic conditions in the mid-crust reached >650°C and 4.4–7 kbar at c. 1,210–1,200 Ma. Most samples record a single clockwise P–T evolution during this event, although some samples might have experienced multiple perturbations. The heat source for metamorphism was primarily conductive heating of radiogenic mid- and upper crust, derived from earlier crustal differentiation events. This crust was thickened during D1 transpression, although the thermal effects persisted longer than the deformation event. Peak metamorphism was terminated by D2 transtension at c. 1,210 Ma, with subsequent cooling driven by thinning of the radiogenic crust. The coincidence of a sedimentary basin acting as a thermal lid and a highly radiogenic mid-crustal batholith restricted to the Mutherbukin Zone accounts for reworking being confined to a discrete crustal corridor. Our results show that radiogenic regions in the shallow to mid crust can elevate the thermal gradient and localize deformation, causing the crust to be more responsive to far-field stresses. The Mutherbukin Tectonic Event in the Capricorn Orogen was synchronous with numerous Mesoproterozoic events around the West Australian Craton, suggesting that thick cratonic roots play an important role in propagating stresses generated at distant plate boundaries.
DS201811-2609
2018
Rasmussen, B.Stark, J.C., Wilde, S.A., Soderlund, U., Li, Z-X., Rasmussen, B., Zi, J-W.First evidence of Archean mafic dykes at 2.62 Ga in the Yilgarn Craton, Western Australia: links to cratonisation and the Zimbabwe craton.Precambrian Research, Vol. 317, pp. 1-13.Australia, Africa, Zimbabwecraton

Abstract: The Archean Yilgarn Craton in Western Australia hosts at least five generations of Proterozoic mafic dykes, the oldest previously identified dykes belonging to the ca. 2408-2401?Ma Widgiemooltha Supersuite. We report here the first known Archean mafic dyke dated at 2615?±?6?Ma by the ID-TIMS U-Pb method on baddeleyite and at 2610?±?25?Ma using in situ SHRIMP U-Pb dating of baddeleyite. Aeromagnetic data suggest that the dyke is part of a series of NE-trending intrusions that potentially extend hundreds of kilometres in the southwestern part of the craton, here named the Yandinilling dyke swarm. Mafic magmatism at 2615?Ma was possibly related to delamination of the lower crust during the final stages of assembly and cratonisation, and was coeval with the formation of late-stage gold deposit at Boddington. Paleogeographic reconstructions suggest that the Yilgarn and Zimbabwe cratons may have been neighbours from ca. 2690?Ma to 2401?Ma and if the Zimbabwe and Kaapvaal cratons amalgamated at 2660-2610?Ma, the 2615?Ma mafic magmatism in the southwestern Yilgarn Craton may be associated with the same tectonic event that produced the ca. 2607-2604?Ma Stockford dykes in the Central Zone of the Limpopo Belt. Paleomagnetic evidence and a similar tectonothermal evolution, including coeval low-pressure high-temperature metamorphism, voluminous magmatism, and emplacement of mafic dykes, support a configuration where the northern part of the Zimbabwe Craton was adjacent to the western margin of the Yilgarn Craton during the Neoarchean. Worldwide, reliably dated mafic dykes of this age have so far been reported from the Yilgarn Craton, the Limpopo Belt and the São Francisco Craton.
DS1996-1164
1996
Rasmussen, P.E.Rasmussen, P.E.Trace metals in the environment: a geological perspectiveGeological Survey of Canada, Bulletin. No. 429, 25p. $ 10.00CanadaEnvironment, Geochemistry -trace metals
DS1998-0829
1998
Rasmussen, P.E.Larocque, A.C.L., Rasmussen, P.E.An overview of trace metals in the environment, from mobilization toremediationEnviron. Geology, Vol. 33, No. 2-3, Feb. pp. 85-91GlobalGeochemistry - trace metals, Environment
DS1990-1170
1990
Rasmussen, T.M.Pederson, L.B., Rasmussen, T.M., Dyrelius, D.Construction of component maps from aeromagnetic total field anomaly mapsGeophysical Prospecting, Vol. 38, pp. 795-804GlobalGeophysics, Aeromagnetics- component maps
DS2002-0780
2002
Rasmussen, T.M.Jensen, S.M., Hanson, H., Secher, K., Steenfelt, A., Schjoth, F., Rasmussen, T.M.Kimberlites and other ultramafic alkaline rocks in the Sismiut-Kangerfussuaq region, southwest Greenland.Geology of Greenland Survey Bulletin, No. 191, pp. 57-66.GreenlandDistribution and magnetic signatures of dykes
DS2003-0653
2003
Rasmussen, T.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Greenland exploration dat a on DVD - the guide to future kimberlite targets in theDanmarks og Gronlands Geologiske Undersagelse Rapport, 2003/21, 50p. plus 1 DVD $100.US www.geus.dkGreenlandMineral analyses, samples, drill logs
DS2003-0654
2003
Rasmussen, T.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Diamond exploration dat a from West GreenlandDanmarks OG Gronlands Geologiske Undersogelse, Rapport 2003-21, 50p.GreenlandBlank
DS2003-0655
2003
Rasmussen, T.M.Jensen, S.M., Secher, K., Rasmussen, T.M., Tukiainen, T., Krebs, J.D., Schifth, F.Distribution and magnetic signatures of kimberlitic rocks in the Sarfartoq region8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractGreenlandBlank
DS200412-0912
2003
Rasmussen, T.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Greenland exploration dat a on DVD - the guide to future kimberlite targets in the compilation Diamond Exploration dat a from WestDanmarks OG Gronlands Geologiske Undersogelse, 2003/21, 50p. plus 1 DVD $100.US www.geus.dkEurope, GreenlandMaps, tables, data from assessment reports, GIS, Pdf Mineral analyses, samples, drill logs
DS200412-0913
2003
Rasmussen, T.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Diamond exploration dat a from West Greenland.Danmarks OG Gronlands Geologiske Undersogelse, Rapport 2003-21, 50p.Europe, GreenlandOverview of available company data, analyses
DS200412-0914
2003
Rasmussen, T.M.Jensen, S.M., Secher, K., Rasmussen, T.M., Tukiainen, T., Krebs, J.D., Schifth, F.Distribution and magnetic signatures of kimberlitic rocks in the Sarfartoq region, southern West Greenland.8 IKC Program, Session 8, POSTER abstractEurope, GreenlandDiamond exploration
DS201602-0203
2016
Rasmusson, B.Downes, P.J., Dunkley, D.J., Fletcher, I.R., McNaughton, N.J., Rasmusson, B., Jaques, A.L., Verall, M., Sweetapple, M.T.Zirconolite, zircon and monazite-(Ce) U-Th-Pb age constraints on the emplacement, deformation and alteration history of the Cummins Range carbonatite complex, Halls Creek orogen, Kimberley region, Western Australia.Mineralogy and Petrology, In press available, 24p.AustraliaCarbonatite

Abstract: In situ SHRIMP U-Pb dating of zirconolite in clinopyroxenite from the Cummins Range Carbonatite Complex, situated in the southern Halls Creek Orogen, Kimberley region, Western Australia, has provided a reliable 207Pb/206Pb age of emplacement of 1009 ± 16 Ma. Variably metamict and recrystallised zircons from co-magmatic carbonatites, including a megacryst ~1.5 cm long, gave a range of ages from ~1043-998 Ma, reflecting partial isotopic resetting during post-emplacement deformation and alteration. Monazite-(Ce) in a strongly foliated dolomite carbonatite produced U-Th-Pb dates ranging from ~900-590 Ma. Although the monazite-(Ce) data cannot give any definitive ages, they clearly reflect a long history of hydrothermal alteration/recrystallisation, over at least 300 million years. This is consistent with the apparent resetting of the Rb-Sr and K-Ar isotopic systems by a post-emplacement thermal event at ~900 Ma during the intracratonic Yampi Orogeny. The emplacement of the Cummins Range Carbonatite Complex probably resulted from the reactivation of a deep crustal structure within the Halls Creek Orogen during the amalgamation of Proterozoic Australia with Rodinia over the period ~1000-950 Ma. This may have allowed an alkaline carbonated silicate magma that was parental to the Cummins Range carbonatites, and generated by redox and/or decompression partial melting of the asthenospheric mantle, to ascend from the base of the continental lithosphere along the lithospheric discontinuity constituted by the southern edge of the Halls Creek Orogen. There is no evidence of a link between the emplacement of the Cummins Range Carbonatite Complex and mafic large igneous province magmatism indicative of mantle plume activity. Rather, patterns of Proterozoic alkaline magmatism in the Kimberley Craton may have been controlled by changing plate motions during the Nuna-Rodinia supercontinent cycles (~1200-800 Ma).
DS201801-0068
2017
Rasmusson, B.Stark, J.C., Wang, X-C., Denyszyn, S.W., Li, Z-X., Rasmusson, B., Zi, J-W., Sheppard, S., Liu, Y.Newly identified 1.89 Ga mafic dyke swarm in the Archean Yilgarn craton, Western Australia suggests a connection to India.Precambrian Research, in press available 47p.Australia, Indiacraton - Yilgarn

Abstract: The Archean Yilgarn Craton in Western Australia is intruded by numerous mafic dykes of varying orientations, which are poorly exposed but discernible in aeromagnetic maps. Previous studies have identified two craton-wide dyke swarms, the 2408?Ma Widgiemooltha and the 1210?Ma Marnda Moorn Large Igneous Provinces (LIP), as well as limited occurrences of the 1075?Ma Warakurna LIP in the northern part of the craton. We report here a newly identified NW-trending mafic dyke swarm in southwestern Yilgarn Craton dated at 1888?±?9?Ma with ID-TIMS U-Pb method on baddeleyite from a single dyke and at 1858?±?54?Ma, 1881?±?37 and 1911?±?42?Ma with in situ SHRIMP U-Pb on baddeleyite from three dykes. Preliminary interpretation of aeromagnetic data indicates that the dykes form a linear swarm several hundred kilometers long, truncated by the Darling Fault in the west. This newly named Boonadgin dyke swarm is synchronous with post-orogenic extension and deposition of granular iron formations in the Earaheedy basin in the Capricorn Orogen and its emplacement may be associated with far field stresses. Emplacement of the dykes may also be related to initial stages of rifting and formation of the intracratonic Barren Basin in the Albany-Fraser Orogen, where the regional extensional setting prevailed for the following 300?million years. Recent studies and new paleomagnetic evidence raise the possibility that the dykes could be part of the coeval 1890?Ma Bastar-Cuddapah LIP in India. Globally, the Boonadgin dyke swarm is synchronous with a major orogenic episode and records of intracratonic mafic magmatism on many other Precambrian cratons.
DS201412-0724
2013
Rasoamalala, V.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
DS201012-0418
2010
Rasoazanamparany, C.Kusky, T.M., Toraman, E., Raharimahefa, T., Rasoazanamparany, C.Active tectonics of the Alatra Ankay graben system, Madagascar: possible extension of Somalian African diffusive plate boundary?Gondwana Research, Vol. 18, 2-3, pp. 274-294.Africa, MadagascarTectonics
DS200512-0891
2003
Rass, I.Rass, I.Carbonatite derivation from primary magmas with different Ca contents: geochemical evidence. Examples from Siberia and Kaiserstuhl.Periodico di Mineralogia, (in english), Vol. LXX11, 1. April, pp. 147-52.Russia, Yakutia, Europe, GermanyMelilitite
DS201312-0732
2013
Rass, I.Rass, I., Kovalchuk, E.Compositions and zoning of coexiting minerals in alkaline ultrabasic rocks, phoscorites, and carbonatites from the Kovdor Complex, Kola Peninsula.Goldschmidt 2013, AbstractRussia, Kola PeninsulaCarbonatite
DS1982-0515
1982
Rass, I.T.Rass, I.T.Rare Earth Elements in the Rock Forming Minerals of Melilitic Rocks in Alkaline-ultrabasic Complexes.Geochimica Et Cosmochimica Acta, Vol. 46, PP. 1477-1488.Russia, GlobalBlank
DS1985-0367
1985
Rass, I.T.Kravchenko, S.M., Rass, I.T.Alkaline Ultrabasic Formation- the Paragenesis of 2 Comagmatic Series.Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 283, No. 4, PP. 973-978.RussiaBlank
DS1986-0662
1986
Rass, I.T.Rass, I.T., Kravchenko, S.M., Laputina, I.P.Pyroxene zoning and the genesis of alkalic ultramafic rocksDoklady Academy of Science USSR, Earth Science Section, Vol. 280, No. 1-6, October pp. 117-122RussiaAlkaline rocks
DS1987-0376
1987
Rass, I.T.Kravechencko, S.M., Rass, I.T.The alkalic ultramafic rock association. a 'paragenesis' of two comagmaticseriesDoklady Academy of Science USSR, Earth Science Section, Vol.283, No. 1-6, pp. 111-116RussiaAlkalic rocks, Genesis
DS1987-0603
1987
Rass, I.T.Rass, I.T., Frikh-Khar, D.I.Occurrence of carbonatites in the Upper Cretaceous ultrabasic volcanic rocks of Kamchatka.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 294, No.1, pp. 182-186RussiaCarbonatite, Picrite
DS1988-0563
1988
Rass, I.T.Rass, I.T., Frikh-Khar, D.I.Carbonatite find in upper Cretaceous ultramafic volcanics of KamchatkaDoklady Academy of Science USSR, Earth Science Section, Vol. 294, No. 1-6, October pp. 50-54RussiaCarbonatite
DS1995-1020
1995
Rass, I.T.Kravchenko, S.M., Schachoto, L.I., Rass, I.T.The MOHO discontinuity relief and the distribution of kimberlites and carbonatites over the northern craton.Iagod Giant Ore Deposits Workshop, J. Kutina, 10p.RussiaSiberian Platform, Distribution -kimberlites
DS1996-1165
1996
Rass, I.T.Rass, I.T., Laputina, I.P.Composition and zoning of accessory minerals in alkali ultrabasites as indicators of the composition magmas..Geochemistry International, Vol. 33, No. 2, Feb. 1, pp. 62-77RussiaLayered intrusion differentiation, Alkalic rocks, Pervoskite, Carbonatite
DS1997-0635
1997
Rass, I.T.Kravchenko, S., Schachotko, L.I., Rass, I.T.Moho discontinuity relief and the distribution of kimberlites and carbonatites in the northern SiberianGlobal Tectonics and Metallogeny, Vol. 6, No. 2, March pp. 137-140.Russia, SiberiaMantle - MOHO, Platform
DS1998-1214
1998
Rass, I.T.Rass, I.T.Geochemical features of carbonatite indicative of the composition, evolution and differentiation mantle magmaGeochemistry International, Vol. 36, No. 2, Feb. 1, pp. 107-116.RussiaCarbonatite, Mantle magmas
DS1998-1215
1998
Rass, I.T.Rass, I.T., Gerasimov, Laputina, IllupinDiamond occurrence in kimberlites dependent on melting depths and rates of cooling of parental mantle magmas.7th. Kimberlite Conference abstract, pp. 723-4.South Africa, Siberia, RussiaMagmatism, Deposit - Wesselton, Mir
DS1998-1216
1998
Rass, I.T.Rass, I.T., Kravchenko, S.M.Melilite bearing rocks within alkaline ultrabasic complexes: derivatives from SiO2 poor, Ca rich mantle..7th. Kimberlite Conference abstract, pp. 725-6.Russia, Kola, KareolMelilite
DS2000-0794
2000
Rass, I.T.Rass, I.T.Melilite rocks in the alkaline ultrabasic complexes of northwestern Siberia: petrochemistry. geochemistry..Geochemistry International, Vol. 38, No. 10, pp. 1003-12.Russia, SiberiaAlkaline rocks - origin
DS2000-0795
2000
Rass, I.T.Rass, I.T.Melilite rocks in the alkaline ultrabasic complexes of the northwestern Siberia: petrochemistry, geochemistryGeochemistry International, Vol. 38, No. 10, pp. 1003-12.Russia, SiberiaMelilite, Maimecha Kotui Province
DS200512-1024
2003
Rass, I.T.Solova, I.P., Girnis, A.V., Rass, I.T., Keller, J., Kononkova, N.N.Different styles of evolution of CO2 rich alkaline magmas: the role of melt composition in carbonate silicate liquid immiscibility. ( Mahlberg)Periodico di Mineralogia, (in english), Vol. LXX11, 1. April, pp. 87-93.Europe, GermanyMagmatism
DS200612-1129
2006
Rass, I.T.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
DS200712-0875
2007
Rass, I.T.Rass, I.T.Trace elements fractionation in Ca rich and Ca poor alkaline ultrabasic series.Plates, Plumes, and Paradigms, 1p. abstract p. A822.Russia, SiberiaMaimecha-Kotui
DS200812-0940
2008
Rass, I.T.Rass, I.T.Melilite bearing and melilite free rock series in carbonatite complexes: derivatives from separate primary melts.Canadian Mineralogist, Vol. 46, 4, August pp.Carbonatite
DS200912-0612
2009
Rass, I.T.Rass, I.T.Mineral melt partition coefficients of trace elements in melilite bearing and melilite free rocks of carbonatite complexes.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussia, SiberiaMelilite
DS201112-0843
2011
Rass, I.T.Rass, I.T.Geochemical features of carbonatites - derivatives of primary alkaline ultrabasic magmas with different Ca-K-Na ratio.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterGlobalCarbonatite
DS201112-0844
2011
Rass, I.T.Rass, I.T.Geochemical features of carbonatites - derivatives of primary alkaline ultrabasic magmas with different Ca K Na ratio.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.122-123.MantleGeochemistry
DS201112-0845
2011
Rass, I.T.Rass, I.T.Geochemical features of carbonatites - derivatives of primary alkaline ultrabasic magmas with different Ca K Na ratio.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.122-123.MantleGeochemistry
DS202007-1121
2020
Rass, I.T.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
Rass, I.T.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.
DS202109-1487
2021
Rass, I.T.Reguir, E.P., Salinkova, E.B., Yang, P., Chakmouradian, A.R., Stifeeva, M.V., Rass, I.T., Kotov, A.B.U-Pb geochronology of calcite carbonatites and jacupirangite from the Guli alkaline complex, Polar Siberia, Russia.Mineralogical Magazine, Vol. 85, 4, pp. 469-483.Russia, Siberiadeposit - Guli

Abstract: Mantle xenoliths from the Middle-Late Jurassic Obnazhennaya kimberlite are often compared with those from the Udachnaya kimberlite (ca. 367 Ma) to inform the evolution of the Siberia craton. However, there are no direct constraints on the timing of the Obnazhennaya kimberlite eruption. Such uncertainty of the kimberlite age precludes a better understanding of the mantle xenoliths from the Obnazhennaya pipe, and thus also of the evolution of the Siberia craton. This paper reports U-Pb ages for both perovskite from the Obnazhennaya kimberlite and rutile in an Obnazhennaya eclogite xenolith. The fresh perovskite formed during the early stage of magmatic crystallization and yields a U-Pb age of 151.8 ± 2.5 Ma (2?). Rutile in the eclogite xenolith yields an overlapping U-Pb age of 154.2 ± 1.9 Ma (2?). Because rutile has a Pb closure temperature lower than the inferred residence temperature of the eclogite prior to eruption, the U-Pb isotope system in rutile was not closed until the host eclogite was entrained and delivered to the surface by the kimberlite and therefore records the timing of kimberlite eruption. These data provide the first direct constraints on the emplacement age of the Obnazhennaya kimberlite and add to the global ‘kimberlite bloom’ from ca. 250-50 Ma as well as to the largest pulse of kimberlite volcanism in Siberia from ca. 171-144 Ma. The timing of this Jurassic-Cretaceous pulse coincides with the closure of the Mongol-Okhotsk Ocean, but the depleted Sr-Nd isotopic characteristics of 171-144 Ma kimberlites are inconsistent with a subduction-driven model for their petrogenesis. Thus, the closure of the Mongol-Okhotsk Ocean may act as a trigger for the initiation of 171-144 Ma kimberlite emplacement of Siberia, but was not the source.
DS2000-0796
2000
Rass. I.T.Rass. I.T., Plechov, P. Yu.Melt inclusions in olivines from the olivine-melilitite rock of the Guli Massif, northwestern Siberian PlatformDoklady Academy of Sciences, Vol. 375A, No. 9, pp. 1399-02.RussiaMelilitite
DS2002-1312
2002
Rassakazov, S.V.Rassakazov, S.V., Saranina, E.V., Logachev, IvanovThe DUPAL mantle anomaly of the Tuva Mongolian Massif and its paleogeodynamic implication.Doklady, Vol.382, 1, Jan-Feb.pp. 44-8.MongoliaGeodynamics
DS1910-0208
1911
Rasser, E.O.Rasser, E.O.Kimberley und Seine Diamant gruben Mit Besonderer Berucksitchtigung der Enstehung der Diamantenlagerstaetten.Deut. Runds. Georgr. Stat., Vol. 33, PP. 576-580.South Africa, Kimberley AreaRegional Geology, Diamond Genesis
DS1910-0591
1919
Rasser, E.O.Rasser, E.O.Kimberley und Seine Diamanten gruben Mit Besonderer Berucksichtigung der Enstehung der Diamantlagerstaetten.Geologe., No. 25, NOVEMBER, PP. 447-451.South AfricaMining Engineering
DS1998-0667
1998
RasskazovIvanov, 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
DS2000-0062
2000
RasskazovBarry, T.L., Kampunzu, Rasskazov, Ivanov, Zhaivolcanism and rifting: contrast between East African and Central East Asian rifts.Igc 30th. Brasil, Aug. abstract only 1p.East Africa, AsiaTectonics - rifting
DS2002-1001
2002
RasskazovMartynov, Y.A., Chaschin, Rasskazov, SaraninaLate Miocene Pliocene basaltic volcanism in the south of the Russian far East as an indicator of ...Petrology, Vol.10,2,pp.165-83.RussiaLithospheric mantle, heterogeneity continent-ocean
DS2002-1002
2002
RasskazovMartynov, Yu.A., Chaschin, Rasskazov, SaraniniaLate Miocene- Pliocene basaltic volcanism in the south of Russia Far East, an indicator of lithospheric mantlePetrology, Vol. 10, 2, pp. 165-83.Russia, Far EastHeterogeneity in continent - ocean transition zone
DS200512-0031
2002
RasskazovAshchepkov, I.V., Saprykin, A.I., Gerasim, Khmeintkova, Cheremenykk, Safonova, Rasskazov, Kinolin, VladykinPetrochemistry of mantle xenoliths from Sovgavan Plateau, Far East Russia.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 213-222.RussiaXenoliths
DS1994-1287
1994
Rasskazov, A.V.Novgorodova, M.I., Rasskazov, A.V.Generation of high pressure mineral phases of carbon as a result of atemperature crisis in shear flow graphite.Doklady Academy of Sciences Acad. Science, Vol. 322, pp. 126-129.MantleCarbon, Graphite
DS200812-0510
2008
Rasskazov, S.Ivanov, A., Demonterova, E., Rasskazov, S., Yasnygina, T.Low Ti melts from southeastern Siberian traps large igneous province: evidence for a water rich mantle source?Journal of Earth System Science, Vol. 117, 1, pp. 1-21.Russia, SiberiaWater
DS201612-2288
2016
Rasskazov, S.Chuvashova, I., Rasskazov, S., Yasnygina, T.Mid-Miocene thermal impact on the lithosphere by sub-lithospheric convective mantle material: transition from high- to moderate MG magmatism beneath Vitim Plateau, Siberia.Geoscience Frontiers, in press availableRussia, SiberiaConvection

Abstract: High-Mg lavas are characteristic of the mid-Miocene volcanism in Inner Asia. In the Vitim Plateau, small volume high-Mg volcanics erupted at 16-14 Ma, and were followed with voluminous moderate-Mg lavas at 14-13 Ma. In the former unit, we have recorded a sequence of (1) initial basaltic melts, contaminated by crustal material, (2) uncontaminated high-Mg basanites and basalts of transitional (K-Na-K) compositions, and (3) picrobasalts and basalts of K series; in the latter unit a sequence of (1) initial basalts and basaltic andesites of transitional (Na-K-Na) compositions and (2) basalts and trachybasalts of K-Na series. From pressure estimation, we infer that the high-Mg melts were derived from the sub-lithospheric mantle as deep as 150 km, unlike the moderate-Mg melts that were produced at the shallow mantle. The 14-13 Ma rock sequence shows that initial melts equilibrated in a garnet-free mantle source with subsequently reduced degree of melting garnet-bearing material. No melting of relatively depleted lithospheric material, evidenced by mantle xenoliths, was involved in melting, however. We suggest that the studied transition from high- to moderate-Mg magmatism was due to the mid-Miocene thermal impact on the lithosphere by hot sub-lithospheric mantle material from the Transbaikalian low-velocity (melting) domain that had a potential temperature as high as 1510 °?. This thermal impact triggered rifting in the lithosphere of the Baikal Rift Zone.
DS1991-1400
1991
Rasskazov, S.V.Rasskazov, S.V.Hot spot structure of the Western Baikal Rift systemSoviet Geology and Geophysics, Vol. 32, No. 9, pp. 63-70Russia, Lake BaikalTectonics, Baikal Rift
DS1998-0668
1998
Rasskazov, S.V.Ivanov, A.V., Rasskazov, S.V., et al.Late Cenozoic alkaline ultrabasic and alkaline basanite magmatism of thePetrology, Vol. 6, No. 3, pp. 208-229TanzaniaAlkaline rocks, Rungwe volcanic field
DS2000-0797
2000
Rasskazov, S.V.Rasskazov, S.V., Ivanov, A.V., Demonterova, E.I.Deep seated inclusions in Zun Murin basanites (Tunka Rift Valley, Baikal region).Russian Geology and Geophysics, Vol. 41, No. 1, pp. 98-108.RussiaBasanite
DS2001-0967
2001
Rasskazov, S.V.Rasskazov, S.V., Logachev, N.A., Ivanov, A.V., et al.Magmatic episodes of 17 - 19 MA B.P. in the West Rift of Eastern Africa and its geodynamic significance.Doklady Academy of Sciences, Vol. 381, No. 8, Oct/Nov. pp. 921-4.KenyaMagmatism, Tectonics
DS2002-1313
2002
Rasskazov, S.V.Rasskazov, S.V., Bowring, S.A., Hawsh, T., et al.The Pb Nd Sr isotope systematics in heterogeneous continental lithosphere above the convecting mantle domain.Doklady, Vol. 387A, Nov-Dec. No. 9, pp. 1056-9.MantleGeochronology, Convection
DS2003-1131
2003
Rasskazov, S.V.Rasskazov, S.V., Logachev, N.A., Kozhevnikov, V.M., Yanovskaya, T.B.Multistage dynamics of the upper mantle in eastern Asia: relationships betweenDoklady Earth Sciences, Vol. 390, 4, pp. 492-6.Asia, RussiaGeodynamics, Tectonics
DS200412-1630
2003
Rasskazov, S.V.Rasskazov, S.V., Logachev, N.A., Kozhevnikov, V.M., Yanovskaya, T.B.Multistage dynamics of the upper mantle in eastern Asia: relationships between wandering volcanism and low velocity anomalies.Doklady Earth Sciences, Vol. 390, 4, pp. 492-6.Asia, RussiaGeodynamics Tectonics
DS200612-1621
2006
Rasskazov, S.V.Zorin, Y.A., Turutanov, E.K., Kozhevnikov, V.M., Rasskazov, S.V., Ivanov, A.V.Cenozoic upper mantle plumes in east Siberia and central Mongolia and subduction of the Pacific plate.Doklady Earth Sciences, Vol. 409, 5, pp. 723-726.Asia, Mongolia, Russia, SiberiaPlume
DS200612-1622
2006
Rasskazov, S.V.Zorin, Yu.A., Turutanov, E.kh., Kozhevnikov, V.M., Rasskazov, S.V., Ivanov, A.I.The nature of Cenozoic upper mantle plumes in east Siberia and central Mongolia.Russian Geology and Geophysics, Vol. 47, 10, pp. 1046-1059.Russia, Siberia, MongoliaPlume, hot spots
DS200712-0055
2007
Rasskazov, S.V.Barry, T.L., Ivanov, A.V., Rasskazov, S.V., Demonterova, E.I., Dunai, T.J., Davies, G.R., HarrisonHelium isotopes provide no evidence for deep mantle involvement in Wide spread Cenozoic volcanism across central Asia.Lithos, Vol. 95, 3-4, pp. 415-424.AsiaGeochronology
DS200712-0876
2007
Rasskazov, S.V.Rasskazov, S.V., Ilyasova, A.M., Konev, A.A., Yasnygina, Maslovskaya, Feflov, Demonterova, SaraninaGeochemical evidence of the Zadoi alkaline ultramafic Massif, Cis Sayan area southern Siberia.Geochemistry International, Vol. 45, 1, pp. 1-14.Russia, SiberiaAlkalic
DS200812-0511
2008
Rasskazov, S.V.Ivanov, A.V., Demonterova, E.I., Rasskazov, S.V., Yasnygina, T.A.Low Ti melts from the southeastern Siberian Traps large Igneous Province: evidence for a water rich mantle source?Journal of Earth System Science, Vol. 117, 1, pp. 1-21.Russia, SiberiaMelting
DS1992-0642
1992
Rasskazov, S.Y.Haas, J.R., Haskin, L.A., Luhr, J.F., Bowring, S.A., Rasskazov, S.Y.Petrogenesis of quaternary basinites from the Bartoy Volcanic Field of the Baikal Rift Zone, Siberia, RussiaEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.334Russia, Siberia, RussiaBasinite, Baikal Rift Zone
DS1997-0946
1997
Rast, N.Rast, N.Mechanism and sequence of assembly and dispersal of supercontinentsJournal of Geodynamics, Vol. 23, No. 3-4, pp. 155-172.MantleGondwanaland, Supercontinents
DS1900-0446
1906
Rastall, R.H.Rastall, R.H.The Petrography of Rocks Surrounding the Diamond Pipes of The Kimberley District.South African Association Advanced Science, Vol. 2, PP. 269-288.Africa, South AfricaPetrology, Kimberlite Mines And Deposits
DS1910-0352
1913
Rastall, R.H.Hatch, F.H., Rastall, R.H.The Petrology of Sedimentary RocksLondon: George Allen And Co., 425P.South Africa, Southwest Africa, Namibia, Zimbabwe, Liberia, BoKimberlite
DS2001-0443
2001
Rastas, P.Hanski, E., Huhma, H., Rastas, P., Kamenetsky, V.S.The Paleoproterozoic komatiite picrite association of Finnish LaplandJournal of Petrology, Vol. 42, No. 5, pp. 855-76.Finland, LaplandPicrites, Petrology
DS201702-0236
2016
Rastsvetaeva, R.K.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.
DS201810-2305
2018
Rastsvetaeva, R.K.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).
DS1993-0474
1993
Ratanasthien, B.Fyfe, W.S., Powell, M.A., Hart, B.R., Ratanasthien, B.A global crisis: energy in the futureNonrenewable Resources, Vol. 2, No. 3, Fall pp. 187-196GlobalEnergy crisis
DS1983-0530
1983
Ratcliffe, B.W.Ratcliffe, B.W.Presentation by E. Tyler, Executive Director of Ashton Mining Ltd. on Thursday 10th. November 1983.Bp Minerals In House File Note., Nov. 16TH. 2P.Australia, Western AustraliaMarketing, Prices, Investment
DS1998-1217
1998
Ratcliffe, J.T.Ratcliffe, J.T., Bercovici, D., Schubert, G., KroenkeMantle plume heads and initiation of plate tectonic reorganizationsEarth Plan. Sci. Lett, Vol. 156, No. 3-4, March 30, pp. 195-208MantlePlumes, Tectonics, geodynamics
DS1998-1218
1998
Ratcliffe, J.T.Ratcliffe, J.T., Bercovici, Schubert, KroenkeMantle plume heads and the initiation of plate tectonic reorganizationsEarth Sci. Plan. Lett., Vol. 156, No. 3-4, Mar. 30, pp. 195-208.MantlePlumes, Tectonics
DS2003-0809
2003
Raterron, P.Li, Li., Raterron, P., Weidner, D., Chen, J.Olivine flow mechanisms at 8 GPaPhysics of the Earth and Planetary Interiors, Vol. 138, 2, July 16, pp. 113-129.MantlePetrology
DS200412-1127
2003
Raterron, P.Li, Li., Raterron, P., Weidner, D., Chen, J.Olivine flow mechanisms at 8 GPa.Physics of the Earth and Planetary Interiors, Vol. 138, 2, July 16, pp. 113-129.MantlePetrology
DS200612-0813
2006
Raterron, P.Li, l., Long, H., Raterron, P., Weidner, D.Plastic flow of pyrope at mantle pressure and temperature.American Mineralogist, Vol. 91, pp. 517-525.TechnologyUHP, X-ray imaging, garnet
DS200612-0814
2006
Raterron, P.Li, L.,Weidner, D., Raterron, P., Chen, J., Vaughan, M., Mei, S., Durham, B.Deformation of olivine at mantle pressure using D-DIA.European Journal of Mineralogy, Vol. 18, 1, pp. 7-19.TechnologyExperimental petrology
DS201212-0079
2012
Raterron, P.Bollinger, C., Merkel, S., Raterron, P.Rheology and texture development in olivine deformed in the D-DIA at mantle PT conditions.emc2012 @ uni-frankfurt.de, 1p. AbstractMantleRheology
DS201905-1071
2019
Raterron, P.Raterron, P., Bollinger, C., Merkel, S.Olivine intergranular plasticity at mantle pressures and temperatures.Comptes Rendus Geoscience, in press available 6p.Mantleolivine

Abstract: The ductile behavior of olivine-rich rocks is critical to constrain thermal convection in the Earth's upper mantle. Classical olivine flow laws for dislocation or diffusion creep fail to explain the fast post-seismic surface displacements observed by GPS, which requires a much weaker lithosphere than predicted by classical laws. Here we compare the plasticity of olivine aggregates deformed experimentally at mantle pressures and temperatures to that of single crystals and demonstrate that, depending on conditions of stress and temperature, strain accommodated through grain-to-grain interactions - here called intergranular strain - can be orders of magnitude larger than intracrystalline strain, which significantly weakens olivine strength. This result, extrapolated along mantle geotherms, suggests that intergranular plasticity could be dominant in most of the upper mantle. Consequently, the strength of olivine-rich aggregates in the upper mantle may be significantly lower than predicted by flow laws based on intracrystalline plasticity models.
DS1999-0487
1999
Rath, P.C.Mohanty, M., Rath, P.C., Mishra, A.P.Preliminary survey and assessment for locating source rocks and to find out potential area for diamond occurrence in Mahanadi, Ong, Tel and Suktel basins...Geological Society of India Records, Vol. 131,3, pp.229-31.India, OrissaDiamond occurrences, Districts - Jharsuguda, Samalpur, Sundergarh
DS200612-0941
2001
Rath, S.C.Mohanty, M., Sahoo, K.C., Rath, S.C.Ong River basin in Orissa: a possible target for diamond investigation.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 635-646.India, OrissaDiamond exploration
DS1992-1255
1992
Rathakar, J.Rathakar, J.The Proterozoic alkaline and mildly alkaline complexes of South IndiaProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 2, abstract p. 571IndiaAlkaline rocks
DS1900-0585
1907
Rathbone, E.P.Rathbone, E.P.A Visit to the de Beers Consolidated Diamond MinesInstitute of Mining and Metallurgy. Transactions, Vol. 16, PP. 200-204. ALSO: Institute of Mining and Metallurgy. Bulletin., Vol.Africa, South AfricaMining Methods, Production
DS1985-0241
1985
Rathbone, P.A.Gould, D.I., Rathbone, P.A.The Geological Structure of the Molopo Farms Project AreaProceedings of a seminar on the mineral exploration of the Kalahari, Geol., Vol. 29, pp. 160-186BotswanaStructure, Tectonics
DS201412-0725
2014
Ratheesh-Kumar, R.T.Ratheesh-Kumar, R.T., Windley, B.F., Sajeev, K.Tectonic inheritance of the Indian shield: new insights from its elastic thickness structure.Tectonophysics, Vol. 615-616, pp. 40-52.IndiaTectonics
DS201509-0423
2014
Ratheesh-Kumar, R.T.Ratheesh-Kumar, R.T., Ishwar-Kumar, C., Windley, B., Razakamanana, T., Nair, R.R., Sajeev, K.India-Madagascar paleo-fit based on flexural isostasy of their rifted margins.Gondwana Research, Vol. 28, 2, pp. 581-600.India, Africa, MadagascarTectonics

Abstract: The present study contributes new constraints on, and definitions of, the reconstructed plate margins of India and Madagascar based on flexural isostasy along the Western Continental Margin of India (WCMI) and the Eastern Continental Margin of Madagascar (ECMM). We have estimated the nature of isostasy and crustal geometry along the two margins, and have examined their possible conjugate structure. Here we utilize elastic thickness (Te) and Moho depth data as the primary basis for the correlation of these passive margins. We employ the flexure inversion technique that operates in spatial domain in order to estimate the spatial variation of effective elastic thickness. Gravity inversion and flexure inversion techniques are used to estimate the configuration of the Moho/Crust-Mantle Interface that reveals regional correlations with the elastic thickness variations. These results correlate well with the continental and oceanic segments of the Indian and African plates. The present study has found a linear zone of anomalously low-Te (1-5 km) along the WCMI (~1680 km), which correlates well with the low-Te patterns obtained all along the ECMM. We suggest that the low-Te zones along the WCMI and ECMM represent paleo-rift inception points of lithosphere thermally and mechanically weakened by the combined effects of the Marion hotspot and lithospheric extension due to rifting. We have produced an India-Madagascar paleo-fit representing the initial phase of separation based on the Te estimates of the rifted conjugate margins, which is confirmed by a close-fit correlation of Moho geometry and bathymetry of the shelf margins. The matching of tectonic lineaments, lithologies and geochronological belts between India and Madagascar provide an additional support for the present plate reconstruction.
DS1988-0240
1988
Rathman, D.D.Geis, M.W., Rathman, D.D., Zayhowski, J.J., Smythe, D.L., SmithHomoepitaxial semiconducting diamondNational Technical Information Service AD-A202 349/7, 5p. $ A02 $ 10.95GlobalElectrical characteristics, Diamond
DS200812-0941
2008
Rathna, K.Ratnakar, J., Kumar, K.V., Rathna, K.Geochemical investigation of the alkaline mafic dykes in the environs of the Prakasam alkaline province, eastern Ghats Belt, India.Indian Dykes: editors Srivastava, Sivaji, Chalapathi Rao, pp. 291-308.IndiaAlkalic
DS201804-0710
2018
Rathna, K.Kokandakar, G.K., Ghodke, S.S., Rathna, K., Kumar, K.V.Crustal growth along Proterozoic SE India: parameterization of mantle sources, melting, mechanism, and magma differentiation processes.Journal of the Geological Society of India, Vol. 91, 2, pp. 135-146.Indiamagmatism
DS201804-0711
2018
Rathna, K.Kokandakar, G.K., Ghodke, S.S., Rathna, K., Kumar, K.V.Density, viscosity and velocity (ascent rate) of alkaline magmas.Journal of the Geological Society of India, Vol. 91, 2, pp. 135-146.IndiaPrakasam alkaline province

Abstract: Three distinct alkaline magmas, represented by shonkinite, lamprophyre and alkali basalt dykes, characterize a significant magmatic expression of rift-related mantle-derived igneous activity in the Mesoproterozoic Prakasam Alkaline Province, SE India. In the present study we have estimated emplacement velocities (ascent rates) for these three varied alkaline magmas and compared with other silicate magmas to explore composition control on the ascent rates. The alkaline dykes have variable widths and lengths with none of the dykes wider than 1 m. The shonkinites are fine- to medium-grained rocks with clinopyroxene, phologopite, amphibole, K-feldspar perthite and nepheline as essential minerals. They exhibit equigranular hypidiomorphic to foliated textures. Lamprophyres and alkali basalts characteristically show porphyritic textures. Olivine, clinopyroxene, amphibole and biotite are distinct phenocrysts in lamprophyres whereas olivine, clinopyroxene and plagioclase form the phenocrystic mineralogy in the alkali basalts. The calculated densities [2.54-2.71 g/cc for shonkinite; 2.61-2.78 g/cc for lamprophyre; 2.66-2.74 g/cc for alkali basalt] and viscosities [3.11-3.39 Pa s for shonkinite; 3.01-3.28 Pa s for lamprophyre; 2.72-3.09 Pa s for alkali basalt] are utilized to compute velocities (ascent rates) of the three alkaline magmas. Since the lamprophyres and alkali basalts are crystal-laden, we have also calculated effective viscosities to infer crystal control on the velocities. Twenty percent of crystals in the magma increase the viscosity by 2.7 times consequently decrease ascent rate by 2.7 times compared to the crystal-free magmas. The computed ascent rates range from 0.11-2.13 m/sec, 0.23-2.77 m/sec and 1.16-2.89 m/sec for shonkinite, lamprophyre and alkali basalt magmas respectively. Ascent rates increase with the width of the dykes and density difference, and decrease with magma viscosity and proportion of crystals. If a constant width of 1 m is assumed in the magma-filled dyke propagation model, then the sequence of emplacement velocities in the decreasing order is alkaline magmas (4.68-15.31 m/sec) > ultramafic-mafic magmas (3.81-4.30 m/sec) > intermediate-felsic magmas (1.76-2.56 m/sec). We propose that SiO2 content in the terrestrial magmas can be modeled as a semi-quantitative “geospeedometer” of the magma ascent rates.
DS201805-0955
2018
Rathna, K.Kokandakar, G.J., Ghodke, S.S., Rathna, K., Laxman, B. M., Nagaraju, B., Bhosle, M.V., Kumar, K.V.Density, viscosity and velocity ( ascent rate) of alkaline magmas.Journal of the Geological Society of India, Vol. 91, pp. 135-146.IndiaAlkaline - Prakasam

Abstract: Three distinct alkaline magmas, represented by shonkinite, lamprophyre and alkali basalt dykes, characterize a significant magmatic expression of rift-related mantle-derived igneous activity in the Mesoproterozoic Prakasam Alkaline Province, SE India. In the present study we have estimated emplacement velocities (ascent rates) for these three varied alkaline magmas and compared with other silicate magmas to explore composition control on the ascent rates. The alkaline dykes have variable widths and lengths with none of the dykes wider than 1 m. The shonkinites are fine- to medium-grained rocks with clinopyroxene, phologopite, amphibole, K-feldspar perthite and nepheline as essential minerals. They exhibit equigranular hypidiomorphic to foliated textures. Lamprophyres and alkali basalts characteristically show porphyritic textures. Olivine, clinopyroxene, amphibole and biotite are distinct phenocrysts in lamprophyres whereas olivine, clinopyroxene and plagioclase form the phenocrystic mineralogy in the alkali basalts. The calculated densities [2.54-2.71 g/cc for shonkinite; 2.61-2.78 g/cc for lamprophyre; 2.66-2.74 g/cc for alkali basalt] and viscosities [3.11-3.39 Pa s for shonkinite; 3.01-3.28 Pa s for lamprophyre; 2.72-3.09 Pa s for alkali basalt] are utilized to compute velocities (ascent rates) of the three alkaline magmas. Since the lamprophyres and alkali basalts are crystal-laden, we have also calculated effective viscosities to infer crystal control on the velocities. Twenty percent of crystals in the magma increase the viscosity by 2.7 times consequently decrease ascent rate by 2.7 times compared to the crystal-free magmas. The computed ascent rates range from 0.11-2.13 m/sec, 0.23-2.77 m/sec and 1.16-2.89 m/sec for shonkinite, lamprophyre and alkali basalt magmas respectively. Ascent rates increase with the width of the dykes and density difference, and decrease with magma viscosity and proportion of crystals. If a constant width of 1 m is assumed in the magma-filled dyke propagation model, then the sequence of emplacement velocities in the decreasing order is alkaline magmas (4.68-15.31 m/sec) > ultramafic-mafic magmas (3.81-4.30 m/sec) > intermediate-felsic magmas (1.76-2.56 m/sec). We propose that SiO2 content in the terrestrial magmas can be modeled as a semi-quantitative "geospeedometer" of the magma ascent rates.
DS201805-0965
2018
Rathna, K.Nagaraju, B., Ghodke, S.S., Rathna, K., Kokandakar, G.J., Bhosle, M.V., Kumar, K.V.Fractal analysis of in situ host rock nepheline sysenite xenoliths in a micro- shonkinite dyke ( The Elchuru alkaline complex, SE India).Journal of the Geological Society of India, Vol. 91, 3, pp. 263-272.Indiashonkinite

Abstract: Formation of the fragments of the wall-rock during dyking is one of the important manifestations of instantaneous magmatic events. This process is well documented at shallower depths of Earth’s crust but not at deeper levels. In this paper the in situ xenoliths of host rock nepheline syenite within a micro-shonkinite dyke emplaced at mid-crustal depths is described and the fractal theory applied to evaluate origin of the xenoliths. The nepheline syenite xenoliths are angular to oval shaped and sub-millimetre to ~50 cm long. The xenoliths are matrix supported with clasts and matrix being in equal proportions. Partly detached wall-rock fragments indicate incipient xenolith formation, which suggested that the model fragmentation processes is solely due to dyke emplacement. Fractal analytical techniques including clast size distribution, boundary roughness fractal dimension and clast circularity was carried out. The fractal data suggests that hydraulic (tensile) fracturing is the main process of host rock brecciation. However, the clast size and shape are further affected by postfragmentation processes including shear and thermal fracturing, and chemical erosion. The study demonstrates that dyking in an isotropic medium produces fractal size distributions of host rock xenoliths; however, post-fragmentation processes modify original fractal size distributions.
DS1983-0520
1983
Rathor, B.S.Poddar, M., Rathor, B.S.Vlf Survey of the Weathered Layer in Southern IndiaGeophysical Prospecting, Vol. 31, PP. 524-537.India, Andhra PradeshGeophysics
DS1980-0214
1980
Ratnakar, J.Leelanandam, C., Ratnakar, J.Ocellar Lamprophyres from the Purimetla Alkaline Pluton, Prakassam District, Andhra Pradesh.Quarterly Journal of Geology MIN. METL. SOC. INDIA., Vol. 52, No. 3, PP. 77-79.India, Andhra PradeshLamprophyre
DS1989-0873
1989
Ratnakar, J.Leelanandam, C., Srinivasan, T.P., Ratnakar, J.The sub-alkaline and alkaline rocks of the Settupallecomplex, Prakasamdistrict, Andhra Pradesh IndiaGeological Society of India, Memoir, Editor C. LeelanandaM., No. 15, pp. 241-265IndiaAlkaline rocks, Fayalite
DS1989-1254
1989
Ratnakar, J.Ratnakar, J., Leelanandam, C.Petrology of the alkaline plutons from the eastern and southern peninsulaIndiaGeological Society of India, Memoir, Editor C. LeelanandaM., No. 15, pp. 145-176IndiaAlkaline rocks, Tectonics, list of alkali
DS1995-1993
1995
Ratnakar, J.Vijaka Kumar, K., Ratnakar, J.The gabbros of Prakassam alkaline province, Andhra Pradesh, IndiaJournal of Geological Society India, Vol. 46, No. 3, Sept. pp. 245-254.IndiaAlkaline rocks
DS2003-1132
2003
Ratnakar, J.Ratnakar, J.Geology and geochemistry of the magmatic rocks of the Malani igneous suite andJournal Geological Society of India, Vol. 62, 2, pp. 257-62.IndiaCarbonatite
DS200412-1631
2003
Ratnakar, J.Ratnakar, J.Geology and geochemistry of the magmatic rocks of the Malani igneous suite and Tertiary alkaline province of western Rajasthan.Journal Geological Society of India, Vol. 62, 2, pp. 257-62.IndiaCarbonatite
DS200812-0941
2008
Ratnakar, J.Ratnakar, J., Kumar, K.V., Rathna, K.Geochemical investigation of the alkaline mafic dykes in the environs of the Prakasam alkaline province, eastern Ghats Belt, India.Indian Dykes: editors Srivastava, Sivaji, Chalapathi Rao, pp. 291-308.IndiaAlkalic
DS1996-1166
1996
Ratnaker, J.Ratnaker, J., Krishna, D.V. Rama, Kumar, K.V.Geochemistry and origin of the Kellampalle lamprophyre, Prakesam Andhra Pradesh.Journal of Geological Society India, Vol. 48, No. 6, Dec. 1, pp. 697-702.IndiaLamprophyre
DS202006-0917
2020
Ratnayake, N.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).
DS201012-0612
2010
Ratre, K.Ratre, K., De Waele, B., Kumar, Biswal, T., Sinha, S.Shrimp geochronology for the 1450 Ma Lakhna dyke swarm: its implication for the presence of Eoarchean crust in the Bastar Craton and the 1450-517 Ma depositional ageJournal of Asian Earth Sciences, Vol. 39, 6, pp. 565-577.IndiaGeochronology
DS1998-0552
1998
Ratschacher, L.Hacker, B.R., Ratschacher, L., Shuwen, D.uranium-lead (U-Pb) zircon ages constrain the architecture of the ultrahigh pressure Qinling Dabie Orogen, China.Earth and Planetary Science Letters, Vol. 161, No. 1-4, Sept. 1, pp. 215-230.ChinaGeochronology, Dabie Shan area
DS200512-0385
2005
RatschbacherHacker, B., Luffi, P., Lutkov, V., Minaev, Metcalfe, Ratschbacher, Plank, Ducea, Patinodouce, McWiliamsNear ultrahigh pressure processing of continental crust: Miocene crustal xenoliths from the Pamir.Journal of Petrology, Vol. 46, 8, pp. 1661-1687.Asia, PamirXenoliths
DS201112-0846
2011
Ratschbacher, B.Ratschbacher, B., Pfaff, K., Marks, M., Markl, G.Geochemical trends within the lujavrites of the Ilmaussaq intrusion, SW Greenland.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GreenlandAlkalic
DS1989-0099
1989
Ratschbacher, L.Behrmann, J.H., Ratschbacher, L.Archimedes revisited: a structural test of eclogite emplacement models In the Austrian AlpsTerra Nova, Vol. 1, No. 1, pp. 242-252AlpsEclogite
DS1995-0712
1995
Ratschbacher, L.Hacker, B.R., Ratschbacher, L., Webb, L., Shuwen, D.What brought them up? Exhumation of the Dabie Shan ultrahigh pressurerocks.Geology, Vol. 23, No. 8, August pp. 743-746.ChinaCoesite, diamond, Deposit -Dabie Shan area
DS2000-0376
2000
Ratschbacher, L.Hacker, B.R., Ratschbacher, L., Chateigner, D.Exhumation of the ultrahigh pressure continental crust in east central China: Late Triassic -Early JurassicJournal of Geophysical Research, Vol. 105, No. 6, June 10, pp. 13339-Chinaultra high pressure (UHP)
DS2000-0798
2000
Ratschbacher, L.Ratschbacher, L., Hacker, B.R., Wenk, H-R.Exhumation of the ultrahigh pressure continental crust in east central China: Cretaceous and Cenozoic unroof..Journal of Geophysical Research, Vol. 105, No. 6, June 10, pp. 13303-20.Chinaultra high pressure (UHP)
DS2003-0506
2003
Ratschbacher, L.Grimmer, J.C., Ratschbacher, L., McWilliams, M., Franz, L., Gaitzsch, I., et al.When did the ultrahigh-pressure rocks reach the surface? A 207Pb 206 Pb zircon 40Chemical Geology, Vol. 197, 1-4, pp. 87-110.ChinaDabie Shan synorogenic foreland sediments, UHP
DS200412-0728
2003
Ratschbacher, L.Grimmer, J.C., Ratschbacher, L., McWilliams, M., Franz, L., Gaitzsch, I., et al.When did the ultrahigh-pressure rocks reach the surface? A 207Pb 206 Pb zircon 40 Ar 39Ar white mica, Si in white mica, single gChemical Geology, Vol. 197, 1-4, pp. 87-110.ChinaDabie Shan synorogenic foreland sediments UHP
DS200612-0518
2006
Ratschbacher, L.Hacker, B.R., Wallis, S.R., Ratschbacher, L., Grove, M., Gehrels, G.High temperature geochronology constraints on the tectonic history and architecture of the ultrahigh pressure Dabie-Sulu Orogen.Tectonics, Vol. 25, 5, TC5006ChinaUHP, tectonics
DS200612-1130
2006
Ratschbacher, L.Ratschbacher, L., Franz, L., Enkelmann, E., Jonckheere, R., Porschke, A., Hacker, B.R., Dong, S., Zhang, Y.The Sino-Korean Yangtze suture, the Huwan detachment and the Paleozoic Tertiary exhumation of ultra high pressure rocks along the Tongbai Xinxian Dabie Mtns.Geological Society of America, Special Paper, No. 403, pp. 45-76.ChinaUHP
DS201212-0534
2012
Ratschbacher, L.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
Ratschbacher, L.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
DS201312-0047
2013
Ratschbacher, L.Bader, T., Ratschbacher, L., Franz, L., Yang, Z., Hofmann, M., Linneman, U., Yuan, H.The heart of Chin a revisited. 1. Proterozoic tectonics of the Qin Mountains in the core of supercontinent Rodinia.Tectonics, Vol. 32, 3, pp. 661-687.ChinaMagmatism - Dabie orogen
DS201704-0633
2017
Ratschbacher, L.Kooijman, E., Smit, M.A., Ratschbacher, L., Kylander-Clark, A.R.C.A view into crustal evolution at mantle depths.Earth and Planetary Science Letters, Vol. 465, pp. 59-69.MantleGeothermometry

Abstract: Crustal foundering is an important mechanism in the differentiation and recycling of continental crust. Nevertheless, little is known about the dynamics of the lower crust, the temporal scale of foundering and its role in the dynamics of active margins and orogens. This particularly applies to active settings where the lower crust is typically still buried and direct access is not possible. Crustal xenoliths derived from mantle depth in the Pamir provide a unique exception to this. The rocks are well-preserved and comprise a diverse set of lithologies, many of which re-equilibrated at high-pressure conditions before being erupted in their ultrapotassic host lavas. In this study, we explore the petrological and chronological record of eclogite and felsic granulite xenoliths. We utilized accessory minerals - zircon, monazite and rutile - for coupled in-situ trace-element analysis and U-(Th-)Pb chronology by laser-ablation (split-stream) inductively coupled plasma mass spectrometry. Each integrated analysis was done on single mineral zones and was performed in-situ in thin section to maintain textural context and the ability to interpret the data in this framework. Rutile thermo-chronology exclusively reflects eruption (View the MathML source11.17±0.06Ma), which demonstrates the reliability of the U-Pb rutile thermo-chronometer and its ability to date magmatic processes. Conversely, zircon and monazite reveal a series of discrete age clusters between 55-11 Ma, with the youngest being identical to the age of eruption. Matching age populations between samples, despite a lack of overlapping ages for different chronometers within samples, exhibit the effectiveness of our multi-mineral approach. The REE systematics and age data for zircon and monazite, and Ti-in-zircon data together track the history of the rocks at a million-year resolution. The data reveal that the rocks resided at 30-40 km depth along a stable continental geotherm at 720-750?°C until 24-20 Ma, and were subsequently melted, densified, and buried to 80-90 km depth - 20 km deeper than the present-day Moho - at View the MathML source930±35°C. The material descended rapidly, accelerating from 0.9-1.7 mm?yr?1 to 4.7-5.8 mm?yr?1 within 10-12 Myr, and continued descending after reaching mantle depth at 14-13 Ma. The data reflect the foundering of differentiated deep-crustal fragments (2.9-3.5 g?cm?3) into a metasomatized and less dense mantle wedge. Through our new approach in constraining the burial history of rocks, we provided the first time-resolved record of this crustal-recycling process. Foundering introduced vestiges of old evolved crust into the mantle wedge over a relatively short period (c. 10 Myr). The recycling process could explain the variability in the degree of crustal contamination of mantle-derived magmatic rocks in the Pamir and neighboring Tibet during the Cenozoic without requiring a change in plate dynamics or source region.
DS2000-0868
2000
Ratschibacher, L.Schmid, J.C., Ratschibacher, L., Dong, S.How did the foreland react? Yangtze foreland fold and thrust belt deformation related to exhumation of DabieáShanTerra Nova, Vol. 11, No. 6, pp. 266-72.China, eastern Chinaultra high pressure (UHP) - Dabie Shan, Continental crust
DS201212-0275
2012
Ratter, K.Guzmics, T., Mitchell, R.H., Szabo, C., Berkesi, M., Milke, R., Ratter, K.Liquid immiscibility between silicate, carbonate and sulfide melts in melt inclusions hosted in co-precipitated minerals from Kerimasi volcano (Tanzania): evolution of carbonated nephelinitic magma.Contributions to Mineralogy and Petrology, Vol. 164, pp. 101-122.Africa, TanzaniaCarbonatite
DS201212-0276
2012
Ratter, K.Guzmics, T., Mitchell, R.H., Szabo, C., Berkesi, M., Milke, R., Ratter, K.Liquid immiscibility between silicate, carbonate and sulfide melts in melt inclusions hosted in co-precipitated minerals from Kerimasi volcano ( Tanzania): evolution of carbonated nephelinitic magma.Contributions to Mineralogy and Petrology, in press availableAfrica, TanzaniaPetrogenesis
DS1993-0372
1993
RatteronDoukhan, N., Doukhan, J-C., Ingrin, J., Jaoul, RatteronEarly partial melting in pyroxenesAmerican Mineralogist, Vol. 78, pp. 1246-56.MantleMelting - xenoliths
DS2001-1151
2001
Ratti, G.Tassinari, M.M.L., Kahn, H., Ratti, G.Process mineralogy studies of Corrego do Garimpo REE ore, Catalao I alkaline complex, Goais, Brasil.Minerals Engineering, Vol. 14, No. 12, Dec. pp. 1609-17.BrazilCarbonatite, rare earth elements, Deposit - Catalao
DS1991-1477
1991
Rattray, G.Rutz, J., Rattray, G., Wendlandt, E., Lassiter, J.Evolution of Lower crust: granulite facies xenoliths from cratons andriftsEos Transactions, Vol. 72, No. 44, October 29, abstract p. 543MantleDiatremes, Xenoliths
DS200612-0250
2005
Rau, T.K.Chowdary, V.S., Rau, T.K., Bhaskara Rao, K.S., Sridhar, M., Sinha, K.K.Discovery of a new kimberlite cluster - Timmasamudram kimberlite cluster, Wajrakarus kimberlite field, Anantapur district, Andhra Pradesh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 39-41.India, Andhra Pradesh, Dharwar CratonKimberlite - Timmasamudran
DS200612-0969
2005
Rau, T.K.Nayak, S.S., Ravi, S., Reddy, N.S., Rau, T.K.Petrology and geochemistry of the kimberlites of Dharwar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 58-59.India, Andhra Pradesh, Dharwar CratonPetrology
DS200612-1131
2005
Rau, T.K.Rau, T.K.Primary source rocks for placer diamonds (Proterozoic Quaternary and recent) in Panna diamond belt, Madhya Pradesh - a critical review.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 124-130.India, Madhya Pradesh, Aravalli Bundelkhand CratonAlluvials, diamonds
DS200612-1132
2006
Rau, T.K.Rau, T.K.Incidence of diamonds in the beach sands of the Kanykumari Coast, Tamil Nadu.Journal of the Geological Society of India, Vol. 67, Jan. pp. 11-16.India, Tamil NaduHeavy minerals, recovery, study
DS200612-1133
2005
Rau, T.K.Rau, T.K., Kesava Mani, M., Chowdary, V.S., Sinha, K.K.Bodasanipalle kimberlite pipe ( P-14) - a new addition to Wajrakaruru kimberlite field, Anantapur district, A.P.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 45-47.India, Andhra Pradesh, Dharwar CratonKimberlite - Bodasanipalle
DS200612-1134
2005
Rau, T.K.Rau, T.K., Ravi, S., Chowdary, V.S., Bhaskara Rao, K.S., Reddy, N.S.Diamond prospects in Andhra Pradesh - a review.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 29-33.India, Andhra Pradesh, Dharwar CratonBrief overview
DS200612-1135
2005
Rau, T.K.Rau, T.K., Reddy, N.S., Ravi, S., Sridhar, M., Chowdary, V.S., Bhaskara Rao, K.S.Primary source rocks for diamonds in Banaganapalle conglomerate ( Kurnool Group) - a critical appraisal.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 77-79.India, Andhra Pradesh, Dharwar CratonConglomerate - Banaganapalle
DS200612-1136
2005
Rau, T.K.Ravi, S., Rau, T.K., Reddy, N.S., Nayak, S.S.Discovery of a new kimberlite field - the Tungaghadra kimberlite field, Kurnool District, Andhra Pradesh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 42-44.India, Andhra Pradesh, Dharwar CratonKimberlite - Tungaghadra
DS200612-1351
2005
Rau, T.K.Sridhar, M., Rau, T.K.Discovery of a new lamproite field - Ramadugu lamproite field (RLF) Nalgonda district, Andhra Pradesh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 55-57.India, Andhra Pradesh, Dharwar CratonLamproite - Ramadugu
DS1930-0261
1937
Rau, W.Rau, W.Die EdelsteineLeipzig: Verlagsbuchhandlung J.j. Weber., 48P.GlobalKimberlite
DS201412-0875
2014
Raub, T.D.Spencer, C.J., Cawood, P.A., Hawkesowrth, C.J., Raub, T.D., Prave, A.R., Roberts, N.M.W.Proterozoic onset of crustal reworking and collisional tectonics: reappraisal of the zircon oxygen isotope record.Geology, in press availableMantleTectonics
DS1995-1549
1995
Raucci, A.Raucci, A.Mosaic for windowsSpringer Verlag, 192pGlobalMosaic for windows, Book -ad
DS1960-0185
1961
Raucq, P.Raucq, P.Note Preliminaire sur Les Massifs Ultrabasiques du Kasai Central.Soc. Geol. Belge Annual, No. 9-10, P.591.Democratic Republic of Congo, Central AfricaGeology, Related Rocks
DS200612-1306
2005
RaudseppSimandl, G.J., Ferbey, T., Levson, V.M., Robinson, N.D., Lane, R., Smith, R., Demchuk, Raudsepp, HickinKimberlite and diamond indicator minerals in northeast British Columbia, Canada - a reconnaissance survey.British Columbia Geological Survey, Geofile 2005-25, 25p.Canada, British ColumbiaGeochemistry, geochronology, Buffalo Head Terrane
DS200612-0730
2006
Raudsepp, M.Kopylova, M.G., Matveev, S., Raudsepp, M.Searching for primary kimberlite magma,Emplacement Workshop held September, 5p. extended abstractCanada, Northwest TerritoriesDeposit, Jericho, Gahcho Kue, melts
DS200712-0569
2007
Raudsepp, M.Kopylova, M.G., Matveev, S., Raudsepp, M.Searching for parental kimberlite melt.Geochimica et Cosmochimica Acta, Vol. 71, 14, July 15, pp. 3616-3629.MantleDiamond genesis
DS200712-0570
2007
Raudsepp, M.Kopylova, M.G., Matveev, S., Raudsepp, M.Searching for parental kimberlite melt.Geochimica et Cosmochimica Acta, Vol. 71, 14, July 15, pp. 3616-3629.MantleDiamond genesis
DS200712-0571
2007
Raudsepp, M.Kopylova, M.G., Matveev, S., Raudsepp, M.Complex history and abundance of volatiles in kimberlite melts.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.236-237.MantleKimberlite petrology
DS200712-0572
2007
Raudsepp, M.Kopylova, M.G., Matveev, S., Raudsepp, M.Complex history and abundance of volatiles in kimberlite melts.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.236-237.MantleKimberlite petrology
DS200912-0815
2009
Raudsepp, M.Wilson, S.A., Raudsepp, M., Dipple, G.M.Quantifying carbon fixation in trace minerals from processed kimberlite: a comparative study of quantitative methods using X-ray powder diffraction dataApplied Geochemistry, Vol. 24, 12, pp. 2312-2331.Canada, Northwest TerritoriesDeposit - Diavik
DS201807-1516
2018
Raudsepp, M.Mervine, E.M., Wilson, S.A., Power, I.M., Dipple, G.M., Turvey, C.C., Hamilton, J.L., Vanderzee, S., Raudsepp, M., Southam, C., Matter, J.M., Kelemen, P.B., Stiefenhofer, J., Miya, Z., Southam, G.Potential for offsetting diamond mine carbon emissions through mineral carbonation of processed kimberlite: an assessment of De Beers mine sites in South Africa and Canada.Mineralogy and Petrology, 10.1007/ s00710-018- 0589-4, 14p.Africa, South Africa, Canada, Northwest Territories, Ontariodeposit - Venetia, Voorspoed, Gahcho Kue, Victor, Snap Lake

Abstract: De Beers kimberlite mine operations in South Africa (Venetia and Voorspoed) and Canada (Gahcho Kué, Victor, and Snap Lake) have the potential to sequester carbon dioxide (CO2) through weathering of kimberlite mine tailings, which can store carbon in secondary carbonate minerals (mineral carbonation). Carbonation of ca. 4.7 to 24.0 wt% (average?=?13.8 wt%) of annual processed kimberlite production could offset 100% of each mine site’s carbon dioxide equivalent (CO2e) emissions. Minerals of particular interest for reactivity with atmospheric or waste CO2 from energy production include serpentine minerals, olivine (forsterite), brucite, and smectite. The most abundant minerals, such as serpentine polymorphs, provide the bulk of the carbonation potential. However, the detection of minor amounts of highly reactive brucite in tailings from Victor, as well as the likely presence of brucite at Venetia, Gahcho Kué, and Snap Lake, is also important for the mineral carbonation potential of the mine sites.
DS200612-0202
2006
Raue, H.Buttner, R., Dellino, P., Raue, H., Sonder, I., Zimanowski, B.Stress induced brittle fragmentation of magmatic melts: theory and experiments.Journal of Geophysical Research, Vol. 111, No. B8, B08204MantleMagmatism
DS1992-1256
1992
Raufer, R.K.Raufer, R.K.Market-based environmental developmentNatural Resources forum, Vol. 16, No. 2, May pp. 111-116EuropeEconomics, Legal, Environment
DS1950-0509
1959
Raup, O.B.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
DS201605-0824
2016
Rauscher, M.Daniel, M.J., Bellingan, P., Rauscher, M.The modelling of scrubbers and AG mills in the diamond industry and when to use them.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 167-186.TechnologyMining - applied
DS200812-0943
2008
RautelaRay, R., Shukia, A.D., Sheth, H.C., Ray, J.S., Duraiswami, Vanderkluysen, Rautela, MallikHighly heterogeneous Precambrian basement under the central Deccan Traps, India: direct evidence from xenoliths in dykes.Gondwana Research, Vol. 13, 3, pp. 375-385.IndiaPetrology - dykes
DS1920-0117
1922
Rauw, DE.Rauw, DE.Les Gisements Diamantiferes du KasaiMem. Congress Ingen. Ecole Liege., 50P.Democratic Republic of Congo, Central AfricaPetrology, Kimberlite Mines And Deposits
DS2000-0799
2000
Raval, U.Raval, U., Veeraswamy, K.The radial and linear modes of interaction between mantle plume and continental lithosphere: case study...Journal of Geological Society India, Vol. 56, No. 5, Nov. pp. 525-36.IndiaPlumes, dynamics, structures
DS2003-1133
2003
Raval, U.Raval, U.Interaction of mantle plume with Indian continental lithosphere since the CretaceousMemoirs Geological Society of India, Vol. 53, pp. 449-479. Ingenta 1035483313IndiaBlank
DS2003-1134
2003
Raval, U.Raval, U., Veeraswamy, K.India Madagascar separation: break up along a pre-existing mobile belt and chipping ofGondwana Research, Vol. 6, 3, pp. 467-86.Madagascar, IndiaTectonics
DS200412-1632
2003
Raval, U.Raval, U.Interaction of mantle plume with Indian continental lithosphere since the Cretaceous.Memoirs Geological Society of India, Vol. 53, pp. 449-479. Ingenta 1035483313IndiaPlume, subduction
DS200412-1633
2003
Raval, U.Raval, U., Veeraswamy, K.India Madagascar separation: break up along a pre-existing mobile belt and chipping of the craton.Gondwana Research, Vol. 6, 3, pp. 467-86.Africa, MadagascarTectonics
DS200412-2050
2004
Raval, U.Veerswamy, K., Raval, U.Chipping of cratons and breakup along mobile belts of a supercontinent.Earth Planets and Space, Vol. 56, 5, pp.491-500. IngentaIndiaMantle plume, lithosphere, tectonomagmatism
DS200512-1133
2005
Raval, U.Veeraswamy, K., Raval, U.Remobilization of the palaeoconvergent corridors hidden under the Deccan trap cover and some major stable continental region earthquakes.Current Science, Vol. 89, 3, August 10, pp. 522-530.IndiaGeophysics - seismics, tectonics
DS201112-0847
2011
Raval, U.Raval, U., Veeraswarmy, K.Mapping of tectonic corridors through hidden parts of the greater Dharwar terrane.Journal of Asian Earth Sciences, Vol. 42, 6, pp. 1210-1225.IndiaGeophysics - seismics, tectonics
DS1995-1550
1995
Ravat, D.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
DS1995-1879
1995
Ravat, D.Taylor, P.T., Ravat, D.An interpretation of the Magsat anomalies of central EuropeJournal of Applied Geophysics, Vol. 34, pp. 83-91EuropeGeophysics, MAGSAT
DS1999-0583
1999
Ravat, D.Ravat, D., Lu, Z., Braile, L.W.Velocity density relationships and modeling the lithospheric density variations of the Kenya Rift.Tectonophysics, Vol. 301, No. 3-4, Jan. 30, pp. 225-40.KenyaTectonics - rifting, Lithosphere
DS200712-0426
2007
Ravat, D.Hemant, K., Thebault, E., Mandea, M., Ravat, D., Maus, S.Magnetic anomaly map of the world: merging satellite, airborne, marine and ground based magnetic dat a sets.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 56-71.GlobalMap - magnetics
DS200712-0427
2007
Ravat, D.Hemant, K., Thebault, E., Mandea, M., Ravat, D., Maus, S.Magnetic anomaly map of the world: merging satellite, airborne, marine and ground based magnetic dat a sets.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 56-71.GlobalMap - magnetics
DS1993-1284
1993
Ravat, D.H.Ravat, D.H., Hinze, W.J., Taylor, P.T.European tectonic features observed by MAGSATTectonophysics, Vol. 220, No. 1-4, April 15, pp. 157-173.EuropeGeophysics -MAGSAT, Tectonics, Remote sensing
DS1991-0718
1991
Ravat, D.N.Hinze, H.J., Vonfrese, R.R., Ravat, D.N.Mean magnetic contrasts between oceans and continentsTectonophysics, Vol. 192, No. 1-2, Jun. 10, pp. 117-127GlobalMantle, Geophysics -magnetics
DS1992-1257
1992
Ravat, D.N.Ravat, D.N., Hinze, W.J., Vonfrese, R.R.Analysis of magsat magnetic contrasts across Africa and South-AmericaTectonophysics, Vol. 212, No. 1-2, Oct. 1, pp. 59-76.Africa, South AmericaGeophysics -magnetics, Magsat, Remote sensing
DS201810-2372
2018
Raveggi, M.Rielli A., Tomkins, A.G., Nebel, O., Raveggi, M., Jeon, H., Martin, L., Laure, A., Janaina, N.Sulfur isotope and PGE systematics of metasomatised mantle wedge.Earth and Planetary Science Letters, Vol. 497, 1, pp. 181-192.Mantlemetasomatism

Abstract: At convergent margins fluids liberated from subducting slabs metasomatise the overlying mantle wedge, enriching it in volatiles, incompatible elements and possibly ore-forming metals. Despite the genetic link between this process, the genesis of arc magmas, and formation of porphyry Cu-Au deposits, there is currently little understanding of the behaviour of chalcophile and siderophile elements during subduction-related mantle metasomatism. In this study, we report sulfur isotopic compositions and PGE concentrations of sulfides in a suite of garnet peridotites from the Western Gneiss Region of Norway, sampling mantle wedge from ?100 to ?250 km depth. Sulfides hosted in metasomatised samples have deviated from typical mantle values, ranging between ?10.0 and +5.4‰, indicating derivation of sulfur from subducted crust. Sulfides in pervasively metasomatised samples have atypical PGE signatures, with strong enrichment in Os and Ru relative to Ir, whereas channelised fluid flow produced sulfides extremely enriched in Pd, up to 700 times the concentration found in non-metasomatised samples. These signatures are reconcilable with a high oxidation state of the metasomatising agents and demonstrate that subduction can recycle chalcophile and siderophile elements into and within the mantle, along with sulfur. We further show that because the solubility of Os and Ru in fluids is redox sensitive, and Pd is more soluble than the I-PGE, ratios such as Os/Ir, Ru/Ir plotted against Pd/Ir can be used to trace the metasomatic oxidation of mantle samples, mantle-derived magmas and porphyry Cu±Au deposits. This geochemical insight is used to show that Au-rich porphyry Cu deposits are derived from more oxidised mantle wedge than Au-poor porphyry deposits.
DS202010-1871
2020
Raveggi, M.Rebeiro, B.V., Cawood, P.A., Faleiros, F.M., Mulder, J.A., Martin, E., Finch, M.A., Raveggi, M., Teixeira, W., Cordani, U.G., Pavan, M.A long lived active margin revealed by zircon U-Pb-Hf data from the Rio Apa terrane (Brazil): new insights into the Paleoproterozoic evolution of the Amazonian craton.Precambrian Research, 57p. PdfSouth America, Brazilcraton

Abstract: We present the first regional in-situ zircon U-Pb-Hf isotopic data from metaigneous and metasedimentary rocks from the Paleo- to Mesoproterozoic Rio Apa Terrane (RAT), a crustal fragment outcropping in the central-western Brazil and north-eastern Paraguay. These new ages and Hf isotopic data delineate three magmatic events, which record the construction of the temporally and isotopically distinct Western and Eastern Terranes of the RAT. The Western Terrane comprises the 2100-1940 Ma Porto Murtinho Complex and the 1900-1840 Ma Amoguijá Belt, which both define a crustal reworking array in ?HfT-time space evolving from a precursor source with Hf TDM age of ca. 2700 Ma. The 1800-1720 Ma Caracol Belt constitutes the Eastern Terrane and yields suprachondritic ?HfT signatures up to +7.1, indicating significant juvenile input. The metasedimentary Amolar Group and Rio Naitaca Formation in the Western Terrane have maximum depositional ages of 1850-1800 Ma and subchondritic ?HfT signatures down to ?5.7, similar to the underlying basement of the Amoguijá Belt. In the Eastern Terrane, the Alto Tererê Formation has a maximum depositional age of 1750 Ma and mostly suprachondritic ?HfT signatures, similar to magmatic rocks of the underlying Caracol Belt. Together, the new igneous and detrital zircon age and Hf isotopic data record a temporal and spatial transition from 2100 to 1840 Ma crustal reworking in the west to more juvenile magmatism at 1800-1720 Ma in the east. This transition is interpreted to reflect convergent margin magmatism associated with periods of subduction zone advance and retreat in an accretionary orogenic setting. Comparison of the ?HfT-time signature of the RAT with the Amazonian Craton suggest penecontemporaneous development, with the Western and Eastern Terranes of the RAT being correlative with the Ventuari-Tapajós and Rio Negro-Juruena Province of the Amazonian Craton, respectively. Our new data also reveal that the ?HfT signatures of the RAT are distinct from the Maz terrane, which refutes the MARA Block hypothesis.
DS201607-1375
2016
Raveloson, A.Raveloson, A.Seismic structure of the southern part of Madagascar determined by waveform inversion.IGC 35th., Session A Dynamic Earth 1p. AbstractAfrica, MadagascarGeophysics - seismics
DS202011-2067
2020
Raveloson, R.White-Gaynor, A.L., Nyblade, A.A., Durrheim, R., Raveloson, R., van der Meijde, M., Fadel, I., Paulssen, H., Kwadiba, M., Ntibinyane, O., Titus, N., Sitali, M.Lithospheric boundaries and upper mantle structure beneath southern Africa imaged by P and S wave velocity models.Geochemistry, Geophysics, Geosystems, 10.1029/GC008925 20p. PdfAfrica, South AfricaGeophysics, seismic

Abstract: We report new P and S wave velocity models of the upper mantle beneath southern Africa using data recorded on seismic stations spanning the entire subcontinent. Beneath most of the Damara Belt, including the Okavango Rift, our models show lower than average velocities (?0.8% Vp; ?1.2% Vs) with an abrupt increase in velocities along the terrane's southern margin. We attribute the lower than average velocities to thinner lithosphere (~130 km thick) compared to thicker lithosphere (~200 km thick) immediately to the south under the Kalahari Craton. Beneath the Etendeka Flood Basalt Province, higher than average velocities (0.25% Vp; 0.75% Vs) indicate thicker and/or compositionally distinct lithosphere compared to other parts of the Damara Belt. In the Rehoboth Province, higher than average velocities (0.3% Vp; 0.5% Vs) suggest the presence of a microcraton, as do higher than average velocities (1.0% Vp; 1.5% Vs) under the Southern Irumide Belt. Lower than average velocities (?0.4% Vp; ?0.7% Vs) beneath the Bushveld Complex and parts of the Mgondi and Okwa terranes are consistent with previous studies, which attributed them to compositionally modified lithosphere resulting from Precambrian magmatic events. There is little evidence for thermally modified upper mantle beneath any of these terranes which could provide a source of uplift for the Southern African Plateau. In contrast, beneath parts of the Irumide Belt in southern and central Zambia and the Mozambique Belt in central Mozambique, deep?seated low velocity anomalies (?0.7% Vp; ?0.8% Vs) can be attributed to upper mantle extensions of the African superplume structure.
DS1998-0226
1998
Raven, W.Cavey, G., Raven, W., Lebel, J.L.Metallic and industrial mineral assessment report on the exploration work in the Calling Lake area.Alberta Geological Survey, MIN 19980021AlbertaExploration - assessment, Cambridge Minerals, Ltd.
DS200912-0118
2009
Ravenna, M.Cobden, L., Goes, S., Ravenna, M., Styles, E., Cammarano, F., Gallagher, K., Connolly, J.Thermochemical interpretation of 1-D seismic dat a for the lower mantle: the significance of nonadiabiatic thermal gradients and compositional heterogeneity.Journal of Geophysical Research, Vol. 114, B 11, B11309MantleGeophysics - seismics. geothermometry
DS201808-1783
2018
Ravenna, M.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.
DS1998-0528
1998
RavenscroftGraham, I., Burgess, bryan, Ravenscroft, Thomas, DoyleThe Diavik kimberlites - Lac de Gras, Northwest Territories, Canada7th International Kimberlite Conference Abstract, pp. 259-61.Northwest TerritoriesHistory, kimberlite, evaluation, Deposit - Diavik
DS1998-0176
1998
Ravenscroft, P.Bryan, D., Burgess, J., Graham, I., Ravenscroft, P.The Diavik kimberlites - Lac de Gras, Northwest Territories, Canada.Calgary Mining Forum, Apr. 8-9, p. 40-2. abstractNorthwest TerritoriesGeology, Deposit - Diavik
DS201702-0237
2017
Ravenscroft, P.Ravenscroft, P.Diamond Resource Evaluation - evolution of techniques from African roots.PDAC 2017, March 6, 1p. AbstractTechnologyEconomics - evaluation
DS1992-1258
1992
Ravenscroft, P.J.Ravenscroft, P.J.Recoverable reserve estimation by conditional simulationGeological Society Special Publication, Case histories and methods in mineral, No. 63, pp. 289-298GlobalComputer, Ore reserves, geostatistics
DS1992-1259
1992
Ravenscroft, P.J.Ravenscroft, P.J.Risk analysis for mine scheduling by conditional simulationTransactions of the Institute of Mining and Metallurgy (IMM), Vol. 101, May-August pp. A104-A108GlobalMining, Ore reserves, Computer scheduling
DS1994-1440
1994
Ravenscroft, P.J.Ravenscroft, P.J.The assessment of reserve estimation risk by conditional simulationRisk Assessment in the extractive industries March 23-24th. 1994, 10pGlobalEconomics, ore reserve evaluation, Statistics, geostatistics
DS201606-1106
2016
Ravi, G.Ray, L., Nagaraju, P., Singh, S.P., Ravi, G., Roy, S.Radioelemental, petrological and geochemical characterization of the Bundelk hand craton, central India: implication in the Archean geodynamic evolution.International Journal of Earth Sciences, Vol. 105, 4, pp. 1087-1107.IndiaNot specific to diamonds

Abstract: We have carried out radioelemental (232Th, 238U, 40K), petrological and geochemical analyses on granitoids and gneisses covering major rock formations of the Bundelkhand craton, central India. Our data reveal that above characteristics are distinct among granitoids (i.e. pink, biotite and grey granitoids) and gneisses (i.e. potassic and sodic types). Pink granitoid is K-feldspar-rich and meta-aluminous to per-aluminous in character. Biotite granitoid is meta-aluminous in character. Grey granitoid is rich in Na-feldspar and mafic minerals, granodiorite to diorite in composition and meta-aluminous in character. Among these granitoids, radioelements (Th, U, K) are highest in pink granitoid (45.0 ± 21.7 ppm, 7.2 ± 3.4 ppm, 4.2 ± 0.4 %), intermediate in biotite granitoid (44.5 ± 28.2 ppm, 5.4 ± 2.8 ppm, 3.4 ± 0.7 %) and lowest in grey granitoid (17.7 ± 4.3 ppm, 4.4 ± 0.6 ppm, 3.0 ± 0.4 %). Among gneisses, potassic-type gneisses have higher radioelements (11.8 ± 5.3 ppm, 3.1 ± 1.2 ppm, 2.0 ± 0.5 %) than the sodic-type gneisses (5.6 ± 2.8 ppm, 1.3 ± 0.5 ppm, 1.4 ± 0.7 %). Moreover, the pink granitoid and the biotite granitoid have higher Th/U (6 and 8, respectively) compared to the grey granitoid (Th/U: 4), implying enrichment of Th in pink and biotite granitoids relative to grey granitoid. K/U among pink, biotite and grey granitoids shows little variation (0.6 × 104, 0.6 × 104, 0.7 × 104, respectively), indicating relatively similar increase in K and U. Therefore, mineralogical and petrological data along with radioelemental ratios suggest that radioelemental variations in these lithounits are mainly related to abundances of the radioactive minerals that have formed by the fractionation of LILE from different magma sources. Based on present data, the craton can be divided into three distinct zones that can be correlated with its evolution in time and space. The central part, where gneisses are associated with metavolcanics of greenstone belt, is characterized by lowest radioelements and is the oldest component. The southern part, dominated by pink granitoid, is characterized by highest radioelements and is the youngest part. The northern part, dominated by grey and biotite granitoid, is characterized by moderate radioelements.
DS1989-0017
1989
Ravi, K.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
DS1999-0584
1999
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Rao, K.R.P.Search for kimberlites in the granite greenstone terrain in the central segment of Wajrakarur kimberlite field, Anantapur district.Geological Society of India Records, Vol. 132,5, pp.40-43.India, Andhra PradeshKimberlite
DS2003-0005
2003
Ravi, S.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
DS2003-1148
2003
Ravi, S.Reddy, T.A.K., Sridhar, M., Ravi, S., Chakravarthi, V., Neelakantam, S.Petrography and geochemistry of the Krishna lamproite field, Andhra PradeshGeological Society of India Journal, Vol. 61, 2, pp. 131-46.India, Andhra PradeshLamproites
DS200412-0010
2003
Ravi, S.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
DS200412-1414
2001
Ravi, S.Nayak, S.S., Rao, K.R.P., Kudari, S.A.K., Ravi, S.Geology and tectonic setting of kimberlites and lamproites of southern India.Geological Society of India Special Publication, No.58, pp. 603-613.IndiaTectonics
DS200612-0968
2001
Ravi, S.Nayak, S.S., Rao, K.R.P., Kudati, S.A.D., Ravi, S.Geology and tectonic setting of the kimberlites and lamproites of southern India. Wajrakarur, Natayanpet, Dharwar Craton, Chigicherla.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 567-575.India, Andhra PradeshTectonics
DS200612-0969
2005
Ravi, S.Nayak, S.S., Ravi, S., Reddy, N.S., Rau, T.K.Petrology and geochemistry of the kimberlites of Dharwar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 58-59.India, Andhra Pradesh, Dharwar CratonPetrology
DS200612-0970
2005
Ravi, S.Nayak, S.S., Ravi, S., Sridhar, M., Reddy, N.S., Chowdary, V.S., Bhaskara Rao, K.S., Sinha, K.K., Rao, T.K.Geology and tectonic setting of kimberlites of Dharwar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 36-38.India, Andhra Pradesh, Dharwar CratonTectonics
DS200612-1046
2006
Ravi, S.Patel, S.C., Ravi, S., Thakur, S.S., Rao, T.K., Subbarao, K.V.Eclogite xenoliths from Wajrakarur kimberlites, southern India.Mineralogy and Petrology., Vol. 88, 1-2, pp. 363-380.IndiaDeposit - Wajrakarur petrology
DS200612-1047
2006
Ravi, S.Patel, S.C., Ravi,S., Thakur, S.S., Rao, T.K., Subbarao, K.V.Eclogite xenoliths from Wajrakarur kimberlites, southern India.Mineralogy and Petrology, Vol. 88, 1-2, pp. 363-380.IndiaDeposit - Wajrakarur
DS200612-1125
2001
Ravi, S.Rao, K.R.P., Nayak, S.S., Reddy, T.A.K., Dhakate, M.V., Chowdary, V.S., Ravi, S., Suresh, G., Rao, K.S.B.Geology, petrology, geochemistry and mineral chemistry of new kimberlite fields in the Wajrakarur kimberlite field, Anantapur district, Andhra Pradesh.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 593-602.India, Andhra PradeshGeochemistry
DS200612-1134
2005
Ravi, S.Rau, T.K., Ravi, S., Chowdary, V.S., Bhaskara Rao, K.S., Reddy, N.S.Diamond prospects in Andhra Pradesh - a review.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 29-33.India, Andhra Pradesh, Dharwar CratonBrief overview
DS200612-1135
2005
Ravi, S.Rau, T.K., Reddy, N.S., Ravi, S., Sridhar, M., Chowdary, V.S., Bhaskara Rao, K.S.Primary source rocks for diamonds in Banaganapalle conglomerate ( Kurnool Group) - a critical appraisal.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 77-79.India, Andhra Pradesh, Dharwar CratonConglomerate - Banaganapalle
DS200612-1136
2005
Ravi, S.Ravi, S., Rau, T.K., Reddy, N.S., Nayak, S.S.Discovery of a new kimberlite field - the Tungaghadra kimberlite field, Kurnool District, Andhra Pradesh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 42-44.India, Andhra Pradesh, Dharwar CratonKimberlite - Tungaghadra
DS200612-1146
2005
Ravi, S.Reddy, T.A.K., Ravi, S.Geology and petrology of the lamproite occurrences in Andhra Pradesh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 60-62.India, Andhra Pradesh, Dharwar CratonLamproite
DS200712-0877
2007
Ravi, S.Ravi, S., Satyanarayana, S.V.Discovery of kimberlites in Chagapuram area, Mahaboobnagar District, Andhra Pradesh.Journal of the Geological Society of India, Vol. 70, 4, pp. 689-692.India, Andhra PradeshKimberlite exploration
DS200812-0857
2008
Ravi, S.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
DS200812-0858
2008
Ravi, S.Patel, S.C., Ravi, S., Rao, C.R.M., Rama Rao, G., Nayak, S.S.Mineralogy and geochemistry of Wajrakaruru kimberlites, southen India.9IKC.com, 3p. extended abstractIndiaDeposit - Wajrakarur petrography
DS201012-0565
2010
Ravi, S.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
DS201012-0613
2010
Ravi, S.Ravi, S., Patel, S.C., Bhaskara Rao, K.S., Valdeswaran, T.Geology of the Chagapuram pyroclastic kimberlites near Kurnool Basin, southern India.International Dyke Conference Held Feb. 6, India, 1p. AbstractIndiaDeposit - Chagapuram arena
DS201212-0069
2012
Ravi, S.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
DS201212-0512
2012
Ravi, S.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
DS201212-0541
2012
Ravi, S.Patel, S.C., Ravi, S., Thakur, S.S.Marid type xenoliths in Proterozoic kimberlites from southern India: implications on mantle metasomatism.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractMantleMetasomatism
DS201212-0579
2012
Ravi, S.Ravi, S., Nayak, S.S., Bhaskara Rao, K.S.Field Guide to southern Indian kimbrlites.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, 63p.IndiaGuidebook
DS201212-0580
2012
Ravi, S.Ravi, S., Sufija, M.V., Patel, S.C., Gupta, T., Sridhar, M., Kaminsky, F.V., Khachatryan, G.K., Netravali, S.V.Diamonds from the eastern Dharwar craton, India: their physical and infrared characteristics.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractIndiaDiamond morphology
DS201312-0343
2012
Ravi, S.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
DS201512-1922
2015
Ravi, S.Guha, A., Kumar, K.V., Ravi, S., Dhananjaya Rao, E.N.Reflectance spectroscopy of kimberlites - in parts of Dharwar Craton, India.Arabian Journal of Geosciences, Vol. 8, no. 11, pp. 9373-9388.IndiaDeposit - Narayanpet

Abstract: In the present study, an attempt was made to analyse the reflectance spectra of kimberlites to evaluate its potential as key in remote sensing based spatial mapping. The spectral profiles of kimberlite samples were collected within the visible-near infrared-shortwave infrared (VNIR-SWIR) electromagnetic domain. In this regard, we analysed the reflectance spectra of three kimberlite pipes (having variable mineralogy) of Narayanpet kimberlite field (NKF) based on the comparative analysis of spectral features of kimberlite samples with the spectral features of their dominant constituent minerals. The relative abundances of each of the constituent minerals were confirmed using semiquantitative mineralogical data from X-ray diffraction analysis. This was supplemented with petrographical data as reference. We found that the absorption features imprinted in the reflectance spectra of kimberlites were mineralogically sensitive. These spectral features were imprinted by spectral features of serpentine, olivine, and calcite depending on the relative dominance of these minerals in kimberlites. With regard to understand the spectral behaviour of weathered residue of kimberlite for targeting buried kimberlite, we also attempted a comparative analysis of spectral profiles of in-situ soil developed above the pipes with the spectra of respective kimberlites in NKF area. While comparing aforementioned spectra, it was observed that the spectral signatures of NKF kimberlites were broadly translated to the in-situ soil. Further, we compared the spectral profiles of selected NKF kimberlites with the spectra of three distinct kimberlite pipes of Wajrakarur kimberlite field (WKF) characterised with similar mineralogy with respect to the selected NKF pipes. Relative dominance of constituent minerals (i.e., serpentine, olivine, calcite, etc.) in these pipes was taken as reference to identify the mineralogical similarity of the pipes of both the field. It was observed that the spectral profiles of NKF and WKF kimberlites were highly correlated with regard to wavelength of diagnostic absorption features. Finally, we also made an attempt to understand the effect of spectral mixing, in spectral separation of kimberlites and associated granite-granodiorite gneiss (i.e., Dharwar Gneiss). It was seen that the spectral contrast of kimberlite and gneiss was dependent on the relative size of the pipe with respect to pixel or ground sampling diameter of spectral data acquisition. Study confirmed the diagnostic nature of reflectance spectra of pipes along with their mineralogical sensitiveness and spatial integrity. It also highlighted how spectral mixing can influence the spectral feature based remote detection of kimberlites.
DS201707-1363
2017
Ravi, S.Shaikh, A.M., Patel, S.C., Ravi, S., Behera, D., Pruseth, K.L.Mineralogy of the TK1 and TK4 'kimberlites' in the Timmasamudram cluster, Wajrakur kimberlite field, India: implications for lamproite magmatism in a field of kimberlites and ultramafic lamprophyres.Chemical Geology, Vol. 455, pp. 208-230.Indiadeposit - Wajrakur

Abstract: A mineralogical study of the hypabyssal facies, late Cretaceous macrocrystic pulse of TK1 intrusion and the Mesoproterozoic aphanitic pulse of TK4 intrusion in the Wajrakarur Kimberlite Field of southern India shows that the rocks contain macrocrysts of forsteritic olivine, phenocrysts and microphenocrysts of Al–Na-poor diopside and phlogopite set in a groundmass mainly of Al–Na-poor diopside and phlogopite. Other groundmass minerals are spinel, perovskite and fluorapatite in TK1, and spinel, titanite, chlorite, calcite and gittinsite in TK4. K-richterite and perovskite occur only as inclusions in phlogopite and titanite, respectively in TK4. Late-stage deuteric phases include pyrite and barite in TK1, and strontianite, chalcopyrite, galena and pentlandite in TK4. Diopside microphenocrysts in TK4 exhibit oscillatory zoning with characteristics of diffusion controlled magmatic growth. TK1 spinels show magmatic trend 2 that evolves from magnesiochromite and culminates in titaniferous magnetite, whereas TK4 spinels are less evolved with magnesiochromite composition only. TK1 phlogopites show a simple compositional trend that is typical of lamproite micas, while four distinct growth zones are observed in TK4 phlogopites with the following compositional characteristics: zone I: high Cr2O3 and TiO2 and low BaO; zone II: low Cr2O3; zone III: low TiO2 and high BaO; zone IV: low BaO. Forsterite contents and trace element concentrations reveal two xenocrystic core populations and one magmatic rim population for TK1 olivines. Mineralogically, both TK1 and TK4 are classified as diopside–phlogopite lamproites rather than archetypal kimberlites. The two lamproites are considered to have formed from the same parent magma but crystallised under distinct oxygen fugacity conditions. With elevated content of Fe3 + in phlogopite, spinel and perovskite, TK1 appears to have crystallised in a relatively high oxygen fugacity environment. Multiple growth generations of phlogopite, spinel and fluorapatite in TK4 indicate a complex evolutionary history of the magma. Close spatial and temporal associations of Mesoproterozoic kimberlites and lamproites in southern India can possibly be explained by a unifying model which accounts for the generation of diverse magmas from a range of geochemical resevoirs in a continental rift setting.
DS201805-0975
2018
Ravi, S.Shaikh, A.M., Kumar, S.P., Patel, S.C.,Thakur, S.S., Ravi, S., Behera, D.The P3 kimberlite and P4 lamproite, Wajrakur kimberlite field, India: mineralogy, and major and minor element compositions of olivines as records of their phenocrystic vs xenocrystic origin.Mineralogy and Petrology, 16p pdfIndiadeposit - Wajrakarur
DS201809-2052
2017
Ravi, S.Kumar, S.P., Patel, S.C., Ravi, S., Pruseth, K.L.Mineralogy of the Banganapalle lamproite, India, and spinel zonation as a record of chemical evolution during crystallization.Geophysical Research Abstracts EGU , Vol. 19, EGU2017-12945-2 1p. AbstractIndialamproites

Abstract: The Mesoproterozoic Banganapalle Lamproite Field of southern India comprises four lamproite dykes which have intruded the Tadpatri Shale of the Cuddapah platformal sedimentary sequence. Mineralogical study of the dyke no. 551/110/4 shows that the rock has an inequigranular texture with megacrysts and macrocrysts of possibly olivine which are completely pseudomorphed by calcite and quartz due to pervasive hydrothermal and/or duteric alteration. Phenocrysts and microphenocrysts of phlogopite are highly chloritised with occasional preservation of relicts. The groundmass is dominated by calcite with subordinate amounts of phlogopite (completely chloritised), diopside, apatite, rutile and spinel. Other minor phases in the groundmass include titanite, allanite, monazite, zircon, barite, carboceranite, pyrite, pyrrhotite, chalcopyrite, galena, sphalerite, heazlewoodite, and pentlandite. Spinel occurs in three textural types: (i) xenocrysts showing homogeneous composition; (ii) phenocrysts and microphenocrysts with continuous compositional zoning from the core to the rim; and (iii) groundmass crystals with distinct growth zones marked by discontinuous compositional zoning from the core to the rim. Four growth zones (zones I-IV) of spinel are recognized. Phenocrysts and microphenocrysts are designated as zone I spinels which have 55.0-65.7 wt% Cr2O3, 2.7-7.2 wt% Al2O3, <0.4 wt% TiO2, and record a decrease in Al/(Al+Cr) from the core to the rim. Zone II spinels either occur as overgrowth rims on xenocrystal and zone I spinels or form cores to zone III rims in discrete grains, and have higher TiO2 (1.2-3.6 wt%), lower Al2O3 (1.2-2.9 wt%) and similar Cr2O3 (55.0-63.8 wt%) contents compared to zone I spinels. Zone III spinels either occur as overgrowth rims on xenocrystal and zone II spinels or form cores to zone IV rims in discrete grains, and contain higher Al2O3 (5.7-10.2 wt%), lower Cr2O3 (45.9-56.0 wt%) and similar TiO2 (1.6-3.4 wt%) compared to zone II spinels. Overgrowth rims of zone II and zone III spinels locally exhibit oscillatory zoning with characteristics of diffusion controlled magmatic growth. Zone IV spinels are marked by low Cr2O3 (17.4-25.5 wt%) and Al2O3 (1.6-2.0 wt%), and high Fe2O3 (28.8-35.4 wt%) and TiO2 (4.0-7.1 wt%) contents. Xenocrystal spinels are distinguished from magmatic spinels by high Al2O3 content (11.3-22.4 wt%) and uniform composition of individual grains. The wide range of composition and the zonation pattern of magmatic spinels suggest that the mineral was on the liquidus through most part of the lamproite crystallisation. The abrupt changes in composition between the zones indicate hiatus in crystallisation and/or sudden changes in the environmental conditions, resulting from crystallisation of associated minerals and periodic emplacement of certain elements into the magma. Diopside occurs in groundmass segregations and has low contents of Na2O (<0.77 wt%), Al2O3 (<1.2 wt%), Cr2O3 (<0.25 wt%) and TiO2 (<1.7 wt%), although higher values of TiO2 (up to 3.0 wt%) are locally encountered. Phenocrystal phlogopite has Mg/(Mg+Fe2+) ratios in the range of 0.76-0.83, and a Cr-rich composition (3.2-3.6 wt% Cr2O3) that indicates its crystallisation at mantle pressures. Co-precipitation of this phlogopite with phencocrystal spinel can explain the observed Al-Cr zoning in the latter.
DS201811-2603
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Ready, R.A.Diamond Fields of southern India. Review in researchgateGeological Survey of India Bulletin Series A, No. 68, 996p. Indiahistory, diamond occurrence
DS201901-0060
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.History of diamond mining in India. GolcondaGeological Survey of India Bulletin A series No. 68, Chapter II pp. 3-25.India, southern Indiahistory

Abstract: Geological Survey of India Bulletin A series No. 68 is available as an open 1,033 page 32 MB pdf.
DS201901-0061
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Diamond deposits and their host rocks. Indian kimberlites and lamproites.Geological Survey of India Bulletin A series No. 68, Chapter III pp. 26-39.India, southern Indiapetrology
DS201901-0062
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Status of diamond - kimberlite-lamproite occurrences in India. Fields Wajrakarur field.Geological Survey of India Bulletin A series No. 68, Chapter IV pp. 40-653.India, southern Indiadeposit - Wajrakarur
DS201901-0063
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Exploration for diamonds in Banaganapalli conglomerates.Geological Survey of India Bulletin A series No. 68, Chapter V pp. 654-748.India, southern Indiadeposit - Banaganapalli
DS201901-0064
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Alluvial diamond deposits. Krishna, Pennar, SagileruGeological Survey of India Bulletin A series No. 68, Chapter VI pp. 749-830.India, southern Indiaalluvials
DS201901-0065
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Mantle xenoliths and xenocrysts.Geological Survey of India Bulletin A series No. 68, Chapter VII pp. 831-850.India, southern Indiametasomatism
DS201901-0066
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Diamonds from SIDP: their physical and infrared characteristics. FTIR ( De Beers studies)Geological Survey of India Bulletin A series No. 68, Chapter VIII pp. 851-910.India, southern Indiadiamond inclusions
DS201901-0067
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Diamond exploration scenario in India: status and future perspectives. Geological Survey of India Bulletin A series No. 68, Chapter IX pp. 911-949.India, southern Indiadiamond exploration
DS201901-0068
2018
Ravi, S.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.References.Geological Survey of India Bulletin A series No. 68, Chapter X pp. 950-973.India, southern Indiareferences
DS201901-0075
2018
Ravi, S.Shaikh, A.M., Patel, S.C., Bussweiler, Y., Kumar, S.P., Tappe, S., Ravi, S., Mainkar, D.Olivine trace element compositions in diamondiferous lamproites from India: proxies for magma origins and the nature of the lithospheric mantle beneath the Bastar and Dharwar cratons.Lithos, doi.org.10.1016/j.lithos.2018.11.026Indiadeposit - Wajrakarur, Mainpur

Abstract: The ~1100?Ma CC2 and P13 lamproite dykes in the Wajrakarur Kimberlite Field (WKF), Eastern Dharwar Craton, and ~65?Ma Kodomali and Behradih lamproite diatremes in the Mainpur Kimberlite Field (MKF), Bastar Craton share a similar mineralogy, although the proportions of individual mineral phases vary significantly. The lamproites contain phenocrysts, macrocrysts and microcrysts of olivine set in a groundmass dominated by diopside and phlogopite with a subordinate amount of spinel, perovskite, apatite and serpentine along with rare barite. K-richterite occurs as inclusion in olivine phenocrysts in Kodomali, while it is a late groundmass phase in Behradih and CC2. Mineralogically, the studied intrusions are classified as olivine lamproites. Based on microtextures and compositions, three distinct populations of olivine are recognised. The first population comprises Mg-rich olivine macrocrysts (Fo89-93), which are interpreted to be xenocrysts derived from disaggregated mantle peridotites. The second population includes Fe-rich olivine macrocrysts (Fo82-89), which are suggested to be the product of metasomatism of mantle wall-rock by precursor lamproite melts. The third population comprises phenocrysts and overgrowth rims (Fo83-92), which are clearly of magmatic origin. The Mn and Al systematics of Mg-rich olivine xenocrysts indicate an origin from diverse mantle lithologies including garnet peridotite, garnet-spinel peridotite and spinel peridotite beneath the WKF, and mostly from garnet peridotite beneath the MKF. Modelling of temperatures calculated using the Al-in-olivine thermometer for olivine xenocrysts indicates a hotter palaeogeotherm of the SCLM beneath the WKF (between 41 and 43?mW/m2) at ~1100?Ma than beneath the MKF (between 38 and 41?mW/m2) at ~65?Ma. Further, a higher degree of metasomatism of the SCLM by precursor lamproite melts has occurred beneath the WKF compared to the MKF based on the extent of CaTi enrichment in Fe-rich olivine macrocrysts. For different lamproite intrusions within a given volcanic field, lower Fo olivine overgrowth rims are correlated with higher phlogopite plus oxide mineral abundances. A comparison of olivine overgrowth rims from the two fields shows that WKF olivines with lower Fo content than MKF olivines are associated with increased XMg in spinel and phlogopite and vice versa. Melt modelling indicates relatively Fe-rich parental melt for WKF intrusions compared to MKF intrusions. The Ni/Mg and Mn/Fe systematics of magmatic olivines indicate derivation of the lamproite melts from mantle source rocks with a higher proportion of phlogopite and/or lower proportion of orthopyroxene for the WKF on the Eastern Dharwar Craton compared to those for the MKF on the Bastar Craton. This study highlights how olivine cores provide important insights into the composition and thermal state of cratonic mantle lithosphere as sampled by lamproites, including clues to elusive precursor metasomatic events. Variable compositions of olivine rims testify to the complex interplay of parental magma composition and localised crystallisation conditions including oxygen fugacity variations, co-crystallisation of groundmass minerals, and assimilation of entrained material.
DS202008-1381
2020
Ravi, S.Choudhary, B.R., Santosh, M., Ravi, S., Babu, EVSSKIndicator mineral ( spinel) from the Wajrakarur kimberlites, southern India: implications for diamond potential and prospectivity.Goldschmidt 2020, 1p. AbstractIndiadeposit - Wajraarur, Kalandurg

Abstract: P-5 and Kl-4 Mesoproterozoic (ca. 1110 Ma) kimberlites from the Wajrakarur and Kalyandurg clusters, Eastern Dharwar craton (EDC), southern India are intruded into the diamondiferous cratonic roots. The spinel compositions is straddling between magnesian ulvöspinel (Group-1 kimberlite) and titanomagnetite (Group-2 kimberlite), comparable with orangeite and lamproites. These Ti-rich minerals have orangeitic affinity, as in the Kaapvaal craton of South Africa, and reflect the high Ti-, high Ca- and the low Al-bearing nature of the parent magma (Group II kimberlites). Larger chrome spinel macrocrysts/xenocrysts show >500 ?m of size with distinctly high chromium (Cr2O3 up to 59.62 wt%), and TiO2-poor (<1.19 wt%). The high chromium spinel macrocrysts represent fragments of mantle xenocrysts and their composition falls within the diamond stability field. The groundmass spinel has been replaced by Ti- schorlomite. The schorlomite garnet represents solid solution of schorlomite -pyrope -almandine-grossular and Crrich schorlomite -pyrope -almandine- uvarovite solid solution. These associations recommend that the schorlomite formed through the replacement of spinel through interaction of late residual fluids/melts in the final stages of crystallization of the kimberlite magma and enrichment in Fe and Ti in schorlomite suggests the involvement of metasomatized sub-continental lithospheric mantle. Present study may have useful application in diamond prospectivity.
DS202009-1657
2020
Ravi, S.Shaikh, A.M., Tappe, S., Bussweiler, Y., Patel, S.C., Ravi, S., Bolhar, R., Viljoen, F.Clinopyroxene and garnet mantle cargo in kimberlites as probes of Dharwar craton architecture and geotherms, with implications for post-1.1 Ga lithosphere thinning events beneath southern India.Journal of Petrology, in press available, 73p. PdfIndiadeposit - Wajrakarur

Abstract: The Wajrakarur Kimberlite Field (WKF) on the Eastern Dharwar Craton in southern India hosts several occurrences of Mesoproterozoic kimberlites, lamproites, and ultramafic lamprophyres, for which mantle-derived xenoliths are rare and only poorly preserved. The general paucity of mantle cargo has hampered the investigation of the nature and evolution of the continental lithospheric mantle (CLM) beneath cratonic southern India. We present a comprehensive study of the major and trace element compositions of clinopyroxene and garnet xenocrysts recovered from heavy mineral concentrates for three ca. 1.1 Ga old WKF kimberlite pipes (P7, P9, P10), with the goal to improve our understanding of the cratonic mantle architecture and its evolution beneath southern India. The pressure-temperature conditions recorded by peridotitic clinopyroxene xenocrysts, estimated using single-pyroxene thermobarometry, suggest a relatively moderate cratonic mantle geotherm of 40?mW/m2 at 1.1 Ga. Reconstruction of the vertical distribution of clinopyroxene and garnet xenocrysts, combined with some rare mantle xenoliths data, reveals a compositionally layered CLM structure. Two main lithological horizons are identified and denoted as layer A (?80-145?km depth) and layer B (?160-190?km depth). Layer A is dominated by depleted lherzolite with subordinate amounts of pyroxenite, whereas layer B comprises mainly refertilised and Ti-metasomatised peridotite. Harzburgite occurs as a minor lithology in both layers. Eclogite stringers occur within the lower portion of layer A and at the bottom of layer B near the lithosphere-asthenosphere boundary at 1.1 Ga. Refertilisation of layer B is marked by garnet compositions with enrichment in Ca, Ti, Fe, Zr and LREE, although Y is depleted compared to garnet in layer A. Garnet trace element systematics such as Zr/Hf and Ti/Eu indicate that both kimberlitic and carbonatitic melts have interacted with and compositionally overprinted layer B. Progressive changes in the REE systematics of garnet grains with depth record an upward percolation of a continuously evolving metasomatic agent. The intervening zone between layers A and B at ?145-160?km depth is characterised by a general paucity of garnet. This ‘garnet-paucity’ zone and an overlying type II clinopyroxene-bearing zone (?115-145?km) appear to be rich in hydrous mineral assemblages of the MARID- or PIC kind. The composite horizon between ?115-160?km depth may represent the product of intensive melt/rock interaction by which former garnet was largely reacted out and new metasomatic phases such as type II clinopyroxene and phlogopite plus amphibole were introduced. By analogy with better-studied cratons, this ‘metasomatic horizon’ may be a petrological manifestation of a former mid-lithospheric discontinuity at 1.1 Ga. Importantly, the depth interval of the present-day lithosphere-asthenosphere boundary beneath Peninsular India as detected in seismic surveys coincides with this heavily overprinted metasomatic horizon, which suggests that post-1.1 Ga delamination of cratonic mantle lithosphere progressed all the way to mid-lithospheric depth. This finding implies that strongly overprinted metasomatic layers, such as the ‘garnet-paucity’ zone beneath the Dharwar craton, present structural zones of weakness that aid lithosphere detachment and foundering in response to plate tectonic stresses.
DS202010-1853
2020
Ravi, S.Kumar, S.P., Shaikh, A.M., Patel, S.C., Sheikh, J.M., Behera, D., Pruseth, K.L., Ravi, S.,Tappe, S.Multi-stage magmatic evidence of olivine-leucite lamproite dykes from Banganapalle, Dharwar craton, India: evidence from compositional zoning of spinel.Mineralogy and Petrology, doi.org/10.1007/s00710-020-00722-y 26p. PdfIndialamproite

Abstract: Mesoproterozoic lamproite dykes occurring in the Banganapalle Lamproite Field of southern India show extensive hydrothermal alteration, but preserve fresh spinel, apatite and rutile in the groundmass. Spinels belong to three genetic populations. Spinels of the first population, which form crystal cores with overgrowth rims of later spinels, are Al-rich chromites derived from disaggregated mantle peridotite. Spinels of the second population include spongy-textured grains and alteration rims of titanian magnesian aluminous chromites that formed by metasomatic interactions between mantle wall-rocks and precursor lamproite melts before their entrainment into the erupting lamproite magma. Spinels that crystallised directly from the lamproite magma constitute the third population and show five distinct compositional subtypes (spinel-IIIa to IIIe), which represent discrete stages of crystal growth. First stage magmatic spinel (spinel-IIIa) includes continuously zoned macrocrysts of magnesian aluminous chromite, which formed together with Al-Cr-rich phlogopite macrocrysts from an earlier pulse of lamproite magma at mantle depth. Crystallisation of spinel during the other four identified stages occurred during magma emplacement at crustal levels. Titanian magnesian chromites (spinel-IIIb) form either discrete crystals or overgrowth rims on spinel-IIIa cores. Further generations of overgrowth rims comprise titanian magnesian aluminous chromite (spinel-IIIc), magnetite with ulvöspinel component (spinel-IIId) and lastly pure magnetite (spinel-IIIe). Abrupt changes of the compositions between successive zones of magmatic spinel indicate either a hiatus in the crystallisation history or co-crystallisation of other groundmass phases, or possibly magma mixing. This study highlights how different textural and compositional populations of spinel provide important insights into the complex evolution of lamproite magmas including clues to elusive precursor metasomatic events that affect cratonic mantle lithosphere.
DS202011-2035
2020
Ravi, S.Choudhary, B.R., Santosh, M., Ravi, S., Babu, E.V.S.S.K.Spinel and Ti-rich schorlomite from the Wajrakarur kimberlites, southern India: implications for metasomatism, diamond potential and orangeite lineage.Ore Geology Reviews, Vol. 126, 103727, 19p. PdfIndiadeposit - Wajrakarur

Abstract: Kl-4 and P-5 mesoproterozoic kimberlite pipes along with several other well-known diamondiferous (ca. 1110 Ma) kimberlites in the Wajrakarur kimberlite field (WKF) intruded into the cratonic roots of Eastern Dharwar craton (EDC) in southern India. The groundmass minerals of the kimberlites exhibit inequigranular texture contain spinel, Ti-rich schorlomite garnet, two generations of olivine (macrocrysts and groundmass microphenocrysts), phlogopite, perovskite, clinopyroxene (diopside), ilmenite (low Mn) and rare apatite. We identified three distinct spinel associations in Kl-4 and P-5: (i) fine-grained (<50 ?m) microcrysts in the groundmass; (ii) resorbed euhedral atoll spinel, consisting of titanomagnetite (magnesian-ulvospinel-magnetite to titanian-chrome-magnetite) which is isolated from the rim of magnetite by spongy lagoon phase of schorlomite, and (iii) larger chrome spinel macrocrysts/xenocrysts (>500 ?m). The schorlomite garnet in both P-5 and Kl-4 represents solid solution of schorlomite-pyrope-almandine-grossular. Additionally, Kl-4 contains another Cr-rich schorlomite-pyrope-almandine-uvarovite solid solution. Macrocrystic spinel exhibits distinct composition of chromium (Cr2O3 up to 59.62 wt%), and poor in TiO2 (<1.19 wt%). The high chromium spinel macrocrysts from Kl-4 are confirmed to be fragments of mantle xenocrysts and their composition falls within the diamond stability field. Atoll-textured epitaxial mantled resorbed spinel associated with schorlomite suggests that they formed through the replacement of spinel possibly through interaction of late residual fluids/melts in the final stages of crystallization of the kimberlite magma. The significant enrichment of Fe and Ti in schorlomite suggests the involvement of metasomatized sub-continental lithospheric mantle. It is also inferred that spinel immiscibility played an important role in the metasomatic replacement. The Ti-rich minerals have orangeitic affinity, similar to those in the Kaapvaal craton of South Africa, and suggest the high Ti-, high Ca- and the low Al-bearing nature of the parent magma (Group II kimberlites). The groundmass tetraferriphlogopite is Al- and Ba-poor and spinel show compositions straddling between magnesian ulvöspinel (Group I kimberlite) and titanomagnetite (Group II kimberlite) comparable with orangeite and lamproites. The results presented in this study suggest that the P-5 and Kl-4 has orengeitic or lamproitic affinity. Our findings can be useful as an indicator mineral in diamond prospecting.
DS202103-0390
2021
Ravi, S.Kumar, S.P., Shaikh, A.M., Patel, S.C., Sheikh, J.M., Behera, D., Pruseth, K.L., Ravi, S., Tappe, S.Multi-stage magmatic history of olivine-leucite lamproite dykes from Banganapalle, Dharwar craton, India: evidence from compositional zoning of spinel.Mineralogy and Petrology, Vol. 115, pp. 87-112. pdfIndialamproite

Abstract: Mesoproterozoic lamproite dykes occurring in the Banganapalle Lamproite Field of southern India show extensive hydrothermal alteration, but preserve fresh spinel, apatite and rutile in the groundmass. Spinels belong to three genetic populations. Spinels of the first population, which form crystal cores with overgrowth rims of later spinels, are Al-rich chromites derived from disaggregated mantle peridotite. Spinels of the second population include spongy-textured grains and alteration rims of titanian magnesian aluminous chromites that formed by metasomatic interactions between mantle wall-rocks and precursor lamproite melts before their entrainment into the erupting lamproite magma. Spinels that crystallised directly from the lamproite magma constitute the third population and show five distinct compositional subtypes (spinel-IIIa to IIIe), which represent discrete stages of crystal growth. First stage magmatic spinel (spinel-IIIa) includes continuously zoned macrocrysts of magnesian aluminous chromite, which formed together with Al-Cr-rich phlogopite macrocrysts from an earlier pulse of lamproite magma at mantle depth. Crystallisation of spinel during the other four identified stages occurred during magma emplacement at crustal levels. Titanian magnesian chromites (spinel-IIIb) form either discrete crystals or overgrowth rims on spinel-IIIa cores. Further generations of overgrowth rims comprise titanian magnesian aluminous chromite (spinel-IIIc), magnetite with ulvöspinel component (spinel-IIId) and lastly pure magnetite (spinel-IIIe). Abrupt changes of the compositions between successive zones of magmatic spinel indicate either a hiatus in the crystallisation history or co-crystallisation of other groundmass phases, or possibly magma mixing. This study highlights how different textural and compositional populations of spinel provide important insights into the complex evolution of lamproite magmas including clues to elusive precursor metasomatic events that affect cratonic mantle lithosphere.
DS202103-0406
2020
Ravi, S.Shaikh, A.M., Tappe, S., Bussweiler, Y., Patel, S.C., Ravi, S., Bolhar, R., Viljoen, F.Clinopyroxene and garnet mantle cargo in kimberlites as probes of Dharwar craton architecture and geotherms, with implications for post -1.1 Ga lithosphere thinning events beneath southern India.Journal of Petrology, Vol. 61, 9, egaa087 23p. PdfIndiadeposit - Wajrakarur

Abstract: The Wajrakarur Kimberlite Field (WKF) on the Eastern Dharwar Craton in southern India hosts several occurrences of Mesoproterozoic kimberlites, lamproites and ultramafic lamprophyres, for which mantle-derived xenoliths are rare and only poorly preserved. The general paucity of mantle cargo has hampered the investigation of the nature and evolution of the continental lithospheric mantle (CLM) beneath cratonic southern India. We present a comprehensive study of the major and trace element compositions of clinopyroxene and garnet xenocrysts recovered from heavy mineral concentrates for three c.1•1?Ga old WKF kimberlite pipes (P7, P9, P10), with the goal to improve our understanding of the cratonic mantle architecture and its evolution beneath southern India. The pressure-temperature conditions recorded by peridotitic clinopyroxene xenocrysts, estimated using single-pyroxene thermobarometry, suggest a relatively moderate cratonic mantle geotherm of 40 mW/m2 at 1•1?Ga. Reconstruction of the vertical distribution of clinopyroxene and garnet xenocrysts, combined with some rare mantle xenoliths data, reveals a compositionally layered CLM structure. Two main lithological horizons are identified and denoted as layer A (?80-145?km depth) and layer B (?160-190?km depth). Layer A is dominated by depleted lherzolite with subordinate amounts of pyroxenite, whereas layer B comprises mainly refertilised and Ti-metasomatized peridotite. Harzburgite occurs as a minor lithology in both layers. Eclogite stringers occur within the lower portion of layer A and at the bottom of layer B near the lithosphere-asthenosphere boundary at 1•1?Ga. Refertilisation of layer B is marked by garnet compositions with enrichment in Ca, Ti, Fe, Zr and LREE, although Y is depleted compared to garnet in layer A. Garnet trace element systematics such as Zr/Hf and Ti/Eu indicate that both kimberlitic and carbonatitic melts have interacted with and compositionally overprinted layer B. Progressive changes in the REE systematics of garnet grains with depth record an upward percolation of a continuously evolving metasomatic agent. The intervening zone between layers A and B at ?145-160?km depth is characterized by a general paucity of garnet. This ‘garnet-paucity’ zone and an overlying type II clinopyroxene-bearing zone (?115-145?km) appear to be rich in hydrous mineral assemblages of the MARID- or PIC kind. The composite horizon between ?115-160?km depth may represent the product of intensive melt/rock interaction by which former garnet was largely reacted out and new metasomatic phases such as type II clinopyroxene and phlogopite plus amphibole were introduced. By analogy with better-studied cratons, this ‘metasomatic horizon’ may be a petrological manifestation of a former mid-lithospheric discontinuity at 1•1?Ga. Importantly, the depth interval of the present-day lithosphere-asthenosphere boundary beneath Peninsular India as detected in seismic surveys coincides with this heavily overprinted metasomatic horizon, which suggests that post-1•1?Ga delamination of cratonic mantle lithosphere progressed all the way to mid-lithospheric depth. This finding implies that strongly overprinted metasomatic layers, such as the ‘garnet-paucity’ zone beneath the Dharwar craton, present structural zones of weakness that aid lithosphere detachment and foundering in response to plate tectonic stresses.
DS2001-0968
2001
Ravi Kama, M.Ravi Kama, M., Saul, J., Shukla, A.K.Crustal structure of the Indian Shield: new constraints from teleseismic receiver functions.Geophysical Research Letters, Vol. 28, No. 7, April 1, pp.1339-42.IndiaTectonics, shield, Geophysics - seismics
DS201312-0733
2013
Ravi Kumar, M.Ravi Kumar, M., Saikia, D., Singh, A., Srinagesh, D., Baidya, P.R., Dattatrayam, R.S.Low shear velocities in the sublithospheric mantle beneath the Indian shield?Journal of Geophysical Research, 50114IndiaTectonics
DS201412-0833
2014
Ravi Kumar, M.Singh, A., Mercier, J-P., Ravi Kumar, M., Srinagesh, D., Chadha, R.K.Continental scale body wave tomography of India: evidence for attrition and preservation of lithospheric roots.Geochemistry, Geophysics, Geosystems: G3, Vol. 15, 3, pp. 658-675.IndiaGeophysics - seismics
DS201806-1242
2018
Ravi Kumar, M.Ravi Kumar, M., Singh, A., Bhaskar Rao, Y.J., Srijayanthi, G., Satyanarayana, H.V., Sarkar, D.Vestiges of Precambrian subduction in the south Indian shield? - A seismological perspective.Tectonophysics, Vol. 740-741, pp. 27-41.Indiageophysics - seismic

Abstract: Investigation of large scale suture zones in old continental interiors offers insights into the evolution of continents. The Dharwar Craton (DC) and the Southern Granulite Terrain(SGT) of the Indian shield represent large segments of Precambrian middle to lower crust and preserve a geological record spanning from Mesoarchean to Cambrian. This study illuminates the deep structure of the Palghat-Cauvery Shear Zone System (PCSS) and the Palghat-Cauvery Suture Zone (PCSZ) that comprise crustal-scale structures related to multiple episodes of orogeny, crust formation and reworking. We utilize here 3202 high quality P-receiver functions computed using new data from a 23 station seismic network operated by us. Results show a thick (>38?km) mafic (Poisson's ratio >0.25) crust beneath the SGT. The change in crustal thickness is gradual, with a shallower Moho towards the south of PCSZ. We found little evidence for drastic changes in crustal thickness across prominent shear zones like the PCSZ and Moyar-Bhavani. Few seismic stations located along these boundaries have shown evidence for dipping reflectors around 8-20?km depth, with strikes matching well with the trends of surface geological sutures. We opine that these suture zones do not show indications of a terrane boundary. However, a drastic change in the crustal thickness is observed around the prograde metamorphic transition zone or broadly, the "Fermor line", which separates rocks of Chanockitic (Orthopyroxene bearing granitoid) and non-Charnockitic (Orthopyroxene-free granitoid) mineral assemblage, further north beneath the DC. We suggest that thicknening of crust north of Moyar-Attur Shear Zone (MASZ) and around Fermor line is related to subduction processes operative during the Precambrian.
DS200412-1634
2002
Ravikant, V.Ravikant, V.Ultrapotassic post collisional dyke from the Laddakh Batholith, Northwest Himalaya.Journal Geological Society of India, Vol. 59, 5, pp. 473-476.India, TibetShoshonite petrography, tectonic, reactivation
DS2002-1319
2002
RavikumarReddy, B.J., Yamauchi, J., Reddy, Ravikumar, ChandraseskharOptical and EPR spectra of Ti 3 in lamprophyllite from Kola Peninsula, RussiaNeues Jahrbuch fur Mineralogie - Monatshefte, No.3, March,ppp.138-40.Russia, Kola PeninsulaMineralogy - titanium
DS1998-1273
1998
Ravizza, G.E.Saal, A.E., Rudnick, R.L., Ravizza, G.E., Hart, S.R.Re - Os isotope evidence for the composition, formation and age of the lower continental crustNature, Vol. 393, No. 6680, May pp. 58-60GlobalGeochronology
DS201112-0665
2011
Ravna, E.Menegon, L., Nasipuri, P., Stunitz, H., Behrens, H., Ravna, E.Dry and strong quartz during deformation of the lower crust in the presence of melt.Journal of Geophysical Research, Vol. 116, B10, B10410MantleMelting
DS2003-0283
2003
Ravna, E.J.Corfu, F., Ravna, E.J., Kullerud, K.A Late Ordovician U Pb age for the Tromse Nappe eclogites, uppermost allochthon ofContribution to Mineralogy and Petrology, Vol. 145, 4. July , pp. 502-513.ScandinaviaGeochronology
DS200412-0369
2003
Ravna, E.J.Corfu, F., Ravna, E.J., Kullerud, K.A Late Ordovician U Pb age for the Tromse Nappe eclogites, uppermost allochthon of the Scandinavian Caledonides.Contributions to Mineralogy and Petrology, Vol. 145, 4. July , pp. 502-513.Europe, ScandinaviaGeochronology
DS201112-0558
2011
Ravna, E.J.K.Kullerud, K., Zozulya, D., Bergh, S.G., Hansen, H., Ravna, E.J.K.Geochemistry and tectonic setting of a lamproite dyke in Kvaloya, north Norway.Lithos, Vol. 126, pp. 278-289.Europe, NorwayLamproite
DS201412-0486
2013
Ravna, E.J.K.Kullerud, K., Zozulya, D., Erambert, M., Ravna, E.J.K.Solid solution between potassic alkali amphiboles from the silica rich lamproite, West Troms basement complex, northern Norway.European Journal of Mineralogy, Vol. 25, pp. 935-945.Europe, NorwayLamproite
DS201412-0778
2014
Ravna, E.J.K.Schingaro, E., Kullerud, K., Lacalamita, M., Mesto, E., Scordari, F., Zozulya, D., Erambert, M., Ravna, E.J.K.Yangzhumgite and phlogopite from the Kvaloya lamproite ( North Norway): structure, composition and origin.Lithos, Vol. 210-211, pp. 1-13.Europe, NorwayLamproite
DS201502-0096
2014
Ravna, E.J.K.Schingaro, E., Kullerud, K., laclamita, M., Mesto, E., Scordari, F., Zozulya, D., Erambert, M., Ravna, E.J.K.Yangzhumingite and phlogopite from the Kvaloya lamproite (North Norway): structure, composition and origin.Lithos, Vol. 210-211, pp. 1-13.Europe, NorwayLamproite
DS2000-0800
2000
Ravna, E.K.Ravna, E.K.Distribution of iron (Fe2) and magnesium between coexisting garnet and hornblende in synthetic and natural systems:Lithos, Vol. 53, No. 3-4, Sept. 1, pp. 265-77.GlobalGeothermometry - empirical calculation Garnet-Hornblend
DS201112-1176
2010
Ravna, E.K.Zozulya, D.R., Savchenko, E.E., Kullerud, K., Ravna, E.K., Lyalina, L.M.Unique accessory Ti-Ba-P mineralization in the Kvaloya ultrapotassic dike, northern Norway.Geology of Ore Deposits, Vol. 52, 8, pp. 843-851.Europe, NorwayMineral chemistry corresponds to lamproite
DS201805-0973
2017
Ravna, E.K.Ravna, E.K., Zozulya, D., Kullerud, K., Corfu, F., Nabelek, P.I., Janak, M., Slagstad, T., Davidsen, B., Selbekk, R.S., Schertl, H-P.Deep seated carbonatite intrusion and metasomatism in the UHP Tromso Nappe, northern Scandinavian Caledonides - a natural example of generation of carbonatite from carbonated eclogite.Journal of Petrology, Vol. 58, 12, pp. 2403-2428.Europe, Sweden, Norwaycarbonatite

Abstract: Carbonatites (sensu stricto) are igneous rocks typically associated with continental rifts, being emplaced at relatively shallow crustal levels or as extrusive rocks. Some carbonatites are, however, related to subduction and lithospheric collision zones, but so far no carbonatite has been reported from ultrahigh-pressure (UHP) metamorphic terranes. In this study, we present detailed petrological and geochemical data on carbonatites from the Tromsø Nappe—a UHP metamorphic terrane in the Scandinavian Caledonides. Massive to weakly foliated silicate-rich carbonate rocks, comprising the high-P mineral assemblage of Mg-Fe-calcite?±?Fe-dolomite?+?garnet?+?omphacitic clinopyroxene?+?phlogopite?+?apatite?+?rutile?+?ilmenite, are inferred to be carbonatites. They show apparent intrusive relationships to eclogite, garnet pyroxenite, garnet-mica gneiss, foliated calc-silicate marble and massive marble. Large grains of omphacitic pyroxene and megacrysts (up to 5?cm across) of Cr-diopside in the carbonatite contain rods of phlogopite oriented parallel to the c-axis, the density of rods being highest in the central part of the megacrysts. Garnet contains numerous inclusions of all the other phases of the carbonatite, and, in places, composite polyphase inclusions. Zircon, monazite and allanite are common accessory phases. Locally, veins of silicate-poor carbonatite (up to 10?cm across) occur. Extensive fenitization by K-rich fluids, with enrichment in phlogopite along contacts between carbonatite and silicate country rocks, is common. Primitive mantle-normalized incompatible element patterns for the carbonatite document a strong enrichment of light rare earth elements, Ba and Rb, and negative anomalies in Th, Nb, Ta, Zr and Hf. The carbon and oxygen isotope compositions of the carbonatite are distinctly different from those of the spatially associated calc-silicate marble, but also from mantle-derived carbonatites elsewhere. Neodymium and Sr isotope data coupled with the trace element distribution indicate a similarity of the Tromsø carbonatite to orogenic (off-craton) carbonatites rather than to anorogenic (on-craton) ones. U-Pb dating of relatively U-rich prismatic, oscillatory-zoned zircon gives an age of 454•5?±?1•1?Ma. We suggest that the primary carbonatite magma resulted from partial melting of a carbonated eclogite at UHP, in a deeply subducted continental slab.
DS201212-0386
2012
Ravna, J.K.Kullerud, K., Zozulya, D., Ravna, J.K.Formation of baotite - a Cl rich silicate - together with fluorapatite and F rich hydrous silicates in the Kvaloya lamproite dyke, North Norway.Mineralogy and Petrology, Vol. 105, 3-4, pp. 145-156.Europe, NorwayLamproite
DS1950-0495
1959
Ravskii, Z.N.Ravskii, Z.N.Geology of Mesozoic and Cenozoic Diamondiferous Deposits Of the South Tunguska Regions.Moscow: Izdat Nauka., 154P.RussiaKimberlite, Textbook, Diamond, Biography, Kimberley
DS1950-0496
1959
Ravskiy, E.I.Ravskiy, E.I.Geology of the Mesozoic and Cenozoic Deposits and the Diamond Contents of the Southern Part of the Tungusska Basin.Akad. Nauk Sssr Izv. Geol. Ser., RussiaKimberlite
DS1995-1551
1995
Raw Materials AlertRaw Materials AlertProceedings of the conference on state participation and privitization In the minerals sectorRaw Materials Report, Vol. 11, No. 3, pp. 38-46GlobalLegal -state privitization, Economics -overview
DS1996-1167
1996
Raw Materials AlertRaw Materials AlertSmall scale mining....brief overview of a new column relating to smallscale miningRaw Materials Alert, Vol. 11, No. 4, pp. 2-3Africa, IndiaNews item, Small scale mining
DS1994-1441
1994
Raw Materials GroupRaw Materials GroupAnnual Review for 1994Raw Materials Group, ScandinaviaAnnual review, Book -ad
DS200612-1137
2006
Raw Materials GroupRaw Materials GroupWorld mining maps.Raw Materials Group, 1:33,000,000 www.rg.se approx. $ 270 UK eachGlobalMap - base metals, precious metals, diamonds
DS201503-0150
2015
Raw Materials GroupICMM, Raw Materials Group, Oxford Policy ManagementThe role of mining in national economies. 2nd editionICMM, Oct. 56p.GlobalEconomics
DS1992-1260
1992
Raw Materials ReportRaw Materials ReportEnvironmental management - guidelines for miningRaw Materials Report, Vol. 8, No. 3, pp. 7-8GlobalLegal, Environmental, Guidelines -brief overview
DS1995-1552
1995
Raw Materials ReportRaw Materials ReportState participation and privitization in the minerals sectorRaw Materials Report, Vol. 11, No. 3, pp. 2-3GlobalEconomics -brief overview
DS2001-1057
2001
RawatShanker, 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
DS200412-1793
2003
Rawat, B.P.Shanker, R., Nag, S., Ganguly, A., Rawat, B.P.Chemistry of common and minor minerals in orangeite ( group II kimberlite) of Majhgawan, Panna District, Madhya Pradesh, India.Indian Journal of Geology, Vol. 73, pp. 207-220.India, Madhya PradeshGeochemistry - orangeite
DS1960-1224
1969
Rawle-Cope, M.Tolansky, S., Rawle-Cope, M.Abundance of Type Ii Diamonds Amongst Natural Micro-diamondsDiamond Research, VOLUME FOR 1969, PP. 2-6.GlobalDiamond Genesis, Classification, Morphology
DS202203-0336
2022
Rawling, T.Boone, S.C., Dalton, H., Prent, A., Kohlman, F., Theile, M., Greau, Y., Florin, G., Noble, W., Hodgekiss, S-A., Ware, B., Phillips, D., Kohn, B., O'Reilly, S., Gleadow, A., McInnes, B., Rawling, T.AusGeochem: an open platform for geochemical data preservation, dissemination and synthesis. Lithodat Pty *** not specific to diamonds but excellent concept/platformGeostandards and Geoanalysis Research, doi.org/10.1111/GGR.12419 34p. PdfAustraliageochemistry

Abstract: To promote a more efficient and transparent geochemistry data ecosystem, a consortium of Australian university research laboratories called the AuScope Geochemistry Network (AGN) assembled to build a collaborative platform for the express purpose of preserving, disseminating, and collating geochronology and isotopic data. In partnership with geoscience-data-solutions company Lithodat Pty Ltd, the open, cloud-based AusGeochem platform (https://ausgeochem.auscope.org.au) was developed to simultaneously serve as a geosample registry, a geochemical data repository, and a data analysis tool. Informed by method-specific groups of geochemistry experts and established international data reporting practices, community-agreed database schemas were developed for rock and mineral geosample metadata and secondary ion mass spectrometry U-Pb analysis, with additional models for laser ablation inductively-coupled mass spectrometry U-Pb and Lu-Hf, Ar-Ar, fission-track and (U-Th-Sm)/He under development. Collectively, the AusGeochem platform provides the geochemistry community with a new, dynamic resource to help facilitate FAIR (Findable, Accessible, Interoperable, Reusable) data management, streamline data dissemination and advanced quantitative investigations of Earth system processes. By systematically archiving detailed geochemical (meta-)data in structured schemas, intractably large datasets comprising thousands of analyses produced by numerous laboratories can be readily interrogated in novel and powerful ways. These include rapid derivation of inter-data relationships, facilitating on-the-fly data compilation, analysis, and visualisation.
DS2002-1314
2002
Rawling, T.J.Rawling, T.J., Lister, G.S.Large scale structure of the eclogite blueschist belt of New CaledoniaJournal of Structural Geology, Vol.24,8,pp. 1239=58.New CaledoniaCrustal extension, shear zones
DS2003-1135
2003
Rawlings Hinchey, A.M.Rawlings Hinchey, A.M., Sylvester, P.J., Meyers, J.S., Dunning, G.R., Kosler, J.Paleoproterozoic crustal genesis: calc-alkaline magmatism of the Torngat OrogenPrecambrian Research, Vol. 125, 1-2, pp. 55-85.Labrador, QuebecMagmatism
DS200412-1635
2003
Rawlings Hinchey, A.M.Rawlings Hinchey, A.M., Sylvester, P.J., Meyers, J.S., Dunning, G.R., Kosler, J.Paleoproterozoic crustal genesis: calc-alkaline magmatism of the Torngat Orogen, Voisey's Bay area, Labrador.Precambrian Research, Vol. 125, 1-2, pp. 55-85.Canada, Quebec, LabradorTectonics Magmatism
DS200512-0510
2004
Rawlinson, N.Kennett, B.L.N., Fishwick, S., Reading, A.M., Rawlinson, N.Contrasts in mantle structure beneath Australia: relation to Tasman Lines?Australian Journal of Earth Sciences, Vol. 51, 4, August pp. 563-370.AustraliaTectonics
DS201312-0009
2013
Rawlinson, N.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
DS201312-0734
2014
Rawlinson, N.Rawlinson, N., Salmon, M., Kennett, B.L.N.Transportable seismic array tomography in southeast Australia: illuminating the transition from Proterozoic to Phanerozoic lithosphere.Lithos, Vol. 189, pp. 65-76.AustraliaGeophysics - seismics
DS201512-1908
2015
Rawlinson, N.Davies, D.R., Rawlinson, N., Iaffaldano, G., Campbell, I.H.Lithospheric controls on magma composition along Earth's longest continental hotspot track.Nature, Vol. 525, 7570, pp. 511-514.AustraliaCosgrove track

Abstract: Hotspots are anomalous regions of volcanism at Earth’s surface that show no obvious association with tectonic plate boundaries. Classic examples include the Hawaiian-Emperor chain and the Yellowstone-Snake River Plain province. The majority are believed to form as Earth’s tectonic plates move over long-lived mantle plumes: buoyant upwellings that bring hot material from Earth’s deep mantle to its surface1. It has long been recognized that lithospheric thickness limits the rise height of plumes2, 3, 4 and, thereby, their minimum melting pressure. It should, therefore, have a controlling influence on the geochemistry of plume-related magmas, although unambiguous evidence of this has, so far, been lacking. Here we integrate observational constraints from surface geology, geochronology, plate-motion reconstructions, geochemistry and seismology to ascertain plume melting depths beneath Earth’s longest continental hotspot track, a 2,000-kilometre-long track in eastern Australia that displays a record of volcanic activity between 33 and 9 million years ago5, 6, which we call the Cosgrove track. Our analyses highlight a strong correlation between lithospheric thickness and magma composition along this track, with: (1) standard basaltic compositions in regions where lithospheric thickness is less than 110 kilometres; (2) volcanic gaps in regions where lithospheric thickness exceeds 150 kilometres; and (3) low-volume, leucitite-bearing volcanism in regions of intermediate lithospheric thickness. Trace-element concentrations from samples along this track support the notion that these compositional variations result from different degrees of partial melting, which is controlled by the thickness of overlying lithosphere. Our results place the first observational constraints on the sub-continental melting depth of mantle plumes and provide direct evidence that lithospheric thickness has a dominant influence on the volume and chemical composition of plume-derived magmas.
DS201809-2058
2018
Rawlinson, N.Liddell, M.V., Bastow, I., Rawlinson, N., Darbyshire, F., Gilligan, A., Watson, E.Precambrian plate tectonics in northern Hudson Bay: evidence from P and S Wave Seismic tomography and analysis of source side effects in relative arrival-time dat a sets.Journal of Geophysical Research, Vol. 123, 7, pp. 5690-5709.Canada, NunavutGeophysics - seismic

Abstract: The geology of northern Hudson Bay, Canada, documents more than 2 billion years of history including the assembly of Precambrian and Archean terranes during several Paleoproterozoic orogenies, culminating in the Trans?Hudson Orogen (THO) ?1.8 Ga. The THO has been hypothesized to be similar in scale and nature to the ongoing Himalaya?Karakoram?Tibetan orogen, but the nature of lithospheric terrane boundaries, including potential plate?scale underthrusting, is poorly understood. To address this problem, we present new P and S wave tomographic models of the mantle seismic structure using data from recent seismograph networks stretching from northern Ontario to Nunavut (60-100?W and 50-80?N). The large size of our network requires careful mitigation of the influence of source side structure that contaminates our relative arrival time residuals. Our tomographic models reveal a complicated internal structure in the Archean Churchill plate. However, no seismic wave speed distinction is observed across the Snowbird Tectonic Zone, which bisects the Churchill. The mantle lithosphere in the central region of Hudson Bay is distinct from the THO, indicating potential boundaries of microcontinents and lithospheric blocks between the principal colliders. Slow wave speeds underlie southern Baffin Island, the leading edge of the generally high wave speed Churchill plate. This is interpreted to be Paleoproterozoic material underthrust beneath Baffin Island in a modern?style subduction zone setting.
DS201911-2517
2019
Rawlinson, N.Davies, D.R., Valentine, A.P., Kramer, S.C., Rawlinson, N., Hoggard, M.J., Eakin, C.M., Wilson, C.R.Earth's multi-scale topographic response to global mantle flow.Nature Geosciences, Vol. 12, pp. 845-850.Mantlegeodynamics

Abstract: Earth’s surface topography is a direct physical expression of our planet’s dynamics. Most is isostatic, controlled by thickness and density variations within the crust and lithosphere, but a substantial proportion arises from forces exerted by underlying mantle convection. This dynamic topography directly connects the evolution of surface environments to Earth’s deep interior, but predictions from mantle flow simulations are often inconsistent with inferences from the geological record, with little consensus about its spatial pattern, wavelength and amplitude. Here, we demonstrate that previous comparisons between predictive models and observational constraints have been biased by subjective choices. Using measurements of residual topography beneath the oceans, and a hierarchical Bayesian approach to performing spherical harmonic analyses, we generate a robust estimate of Earth’s oceanic residual topography power spectrum. This indicates water-loaded power of 0.5?±?0.35?km2 and peak amplitudes of up to ~0.8?±?0.1?km at long wavelengths (~104?km), decreasing by roughly one order of magnitude at shorter wavelengths (~103?km). We show that geodynamical simulations can be reconciled with observational constraints only if they incorporate lithospheric structure and its impact on mantle flow. This demonstrates that both deep (long-wavelength) and shallow (shorter-wavelength) processes are crucial, and implies that dynamic topography is intimately connected to the structure and evolution of Earth’s lithosphere.
DS1975-1195
1979
Rawlinson, P.J.Rawlinson, P.J., Dawson, J.B.A Quench Pyroxene Ilmenite Xenolith from Kimberlite: Implications for Pyroxene Ilmenite Intergrowths.Proceedings of Second International Kimberlite Conference, Proceedings Vol. 2, PP. 292-299.South AfricaWeltevreden, Petrography
DS1992-0779
1992
Rawlinson, R.G.Janulaitis, V., Rawlinson, R.G.Supporting a remote mine in AfricaMinerals Industry International, July pp. 12-15GuineaMining, Aredor mine
DS1993-0157
1993
raxler, J.K.Bram, K., raxler, J.K.KTB Report on basic research and borehole geophysics in the KTB OberplfalzHB deep borehole... 4512.0 -6018.0 M.Ktb Report, No. 93-1, 93-2, table of contents available *requestGermanyBorehole, Super Deep drilling
DS201909-2032
2019
Ray, A.Dasgupta, P., Ray, A., Chakraborti, T.Geochemical characterisation of the Neoarchean newer dolerite dykes of the Bahalda region, Singhbhum craton, Odisha, India: implication for petrogenesis.Journal of Earth Science System, doi:10.1007/s12040- 019-1228-0Indiageochemistry

Abstract: The mafic dyke swarm, newer dolerite dykes (NDDs) intrudes the Archaean Singbhum granite of the Singhbhum craton, eastern India. The present investigation focuses on the petrography and geochemistry of 19 NNE-SSW to NE-SW trending NDDs in two sectors in the northern and south-western part of Bahalda town, Odisha, Singhbhum. Chondrite normalised rare earth element (REE) patterns show light REE (LREE) enrichment among majority of the 13 dykes while the remaining six dykes show a flat REE pattern. Critical analyses of some important trace element ratios like Ba/La, La/Sm, Nb/Y, Ba/Y, Sm/La, Th/La, La/Sm, Nb/Zr, Th/Zr, Hf/Sm, Ta/La and Gd/Yb indicate that the dolerite dykes originated from a heterogeneous spinel peridotite mantle source which was modified by fluids and melts in an arc/back arc setting. REE modelling of these dolerite dykes were attempted on LREE-enriched representative of NDD which shows that these dykes might have been generated by 5-25% partial melting of a modified spinel peridotite source which subsequently suffered around 30% fractional crystallisation of olivine, orthopyroxene and clinopyroxene. The reported age of ~2.75-2.8 Ma seems to be applicable for these dykes and this magmatism appears to be contemporaneous with major scale anorogenic granitic activity in the Singhbhum craton marking a major event of magmatic activity in eastern India.
DS201112-0848
2011
Ray, A.J.Ray, A.J.Ethnohistorical geography and aboriginal rights litigation in Canada: memoir of an expert witness.Canadian Geographer, in press availableCanadaLegal - aboriginal history
DS1985-0179
1985
Ray, A.K.Estreich, S., Ray, A.K., Fry, J.L.Surface Effects in Cluster Calculations of Energy Profiles Of Muonium in Diamond.Phys. Rev. Letters, Vol. 55, No. 19, Nov. 4TH. PP. 1976-1978.GlobalExperimental Petrology
DS1986-0223
1986
Ray, A.K.Estreicher, S., Ray, A.K., Fry, J.L.Interstitial hydrogen in diamond- a detailed Hartree rock analysisPhys. Rev. B., Vol. 34, No. 9, Nov. 1, pp. 6071-6079GlobalDiamond morphology
DS1986-0224
1986
Ray, A.K.Estreicher, S., Ray, A.K., Fry, J.L., Marynick, D.S.Surface effects in cluster calculations of energy profiles of muonium indiamond. reply to commentsPhys. Rev. Letters, Vol. 57, No. 26, p. 3301GlobalCrystallography, Diamond
DS1940-0074
1943
Ray, H.C.Ray, H.C.The Kasai Diamond Fields and their MineralsRocks And Minerals, Vol. 18, No. 11, PP. 340-341.Democratic Republic of Congo, Central AfricaGeology, Mineralogy
DS200612-1138
2006
Ray, J.Ray, J., Ramesh, R.Stable carbon and oxygen isotopic compositions of Indian carbonatites.International Geology Review, Vol. 48, 1, Jan. pp. 17-45.IndiaGeochronology
DS201112-0706
2011
Ray, J.Mukhopadhyay, S., Ray, J., Chattopadhyay, B., Sengupta, S., Ghosh, B., Mukhopadhyay, S.Significance of mineral chemistry of syenites and associated rocks of Elagiri complex, southern granulite terrane of the Indian shield.Journal of the Geological Society of India, Vol. 77, pp. 113-129.IndiaAlkaline rocks, magmatism
DS201707-1361
2017
Ray, J.Saha, A., Ganguly, S., Ray, J., Koeberl, C., Thoni, M., Sarbajna, C., Sawant, S.S.Petrogenetic evolution of Cretaceous Samchampi Samteran alkaline complex, Mikir Hills, northeast India: implications on multiple melting events of heterogeneous plume and metasomatized sub continental lithospheric mantle.Gondwana Research, Vol. 48, pp. 237-256.Indiacarbonatite

Abstract: The Samchampi (26° 13?N: 93° 18?E)-Samteran (26° 11?N: 93° 25?E) alkaline complex (SSAC) occurs as an intrusion within Precambrian basement gneisses in the Karbi-Anglong district of Assam, Northeastern India. This intrusive complex comprises a wide spectrum of lithologies including syenite, ijolite-melteigite, alkali pyroxenite, alkali gabbro, nepheline syenite and carbonatite (nepheline syenites and carbonatites are later intrusives). In this paper, we present new major, trace, REE and Sr-Nd isotope data for different lithologies of SSAC and discuss integrated petrological and whole rock geochemical observations with Sr-Nd isotope systematics to understand the petrogenetic evolution of the complex. Pronounced LILE and LREE enrichment of the alkaline-carbonatite rocks together with steep LREE/HREE profile and flat HREE-chondrite normalized patterns provide evidence for parent magma generation from low degree partial melting of a metasomatized garnet peridotite mantle source. LILE, HFSE and LREE enrichments of the alkaline-silicate rocks and carbonatites are in agreement with the involvement of a mantle plume in their genesis. Nb-Th-La systematics with incompatible trace element abundance patterns marked by positive Nb-Ta anomalies and negative K, Th and Sr anomalies suggest contribution from plume-derived OIB-type mantle with recycled subduction component and a rift-controlled, intraplate tectonic setting for alkaline-carbonatite magmatism giving rise to the SSAC. This observation is corroborated by enriched 87Sr/86Srinitial (0.705562 to 0.709416) and 143Nd/144Ndinitial (0.512187 to 0.512449) ratios for the alkaline-carbonatite rocks that attest to a plume-related enriched mantle (~ EM II) source in relation to the origin of Samchampi-Samteran alkaline complex. Trace element chemistry and variations in isotopic data invoke periodic melting of an isotopically heterogeneous, metasomatized mantle and generation of isotopically distinct melt batches that were parental to the different rocks of SSAC. Various extents of plume-lithosphere interaction also accounts for the trace element and isotopic variations of SSAC. The Srinitial and Ndinitial (105 Ma) isotopic compositions (corresponding to ?Nd values of ? 6.37 to ? 1.27) of SSAC are consistent with those of Sung Valley, Jasra, Rajmahal tholeiites (Group II), Sylhet Traps and Kerguelen plateau basalts.
DS1999-0585
1999
Ray, J.S.Ray, J.S., Pande, K.Carbonatite alkaline magmatism associated with continental flood basalts at stratigraphic boundaries:Geophysical Research Letters, Vol. 26, No. 13, July 1, pp. 1917-20.IndiaCarbonatite, Magmatism - Mass extinction
DS1999-0586
1999
Ray, J.S.Ray, J.S., Ramesh, R., Pande, K.Carbon isotopes in Kerguelen plume derived carbonatites: evidence for recycled inorganic carbon.Earth and Planetary Science Letters, Vol. 170, No. 3, July 15, pp. 205-14.GlobalCarbonatite, Carbon cycle
DS2000-0801
2000
Ray, J.S.Ray, J.S., Pande, K., Venkatesan, T.R.Emplacement of Amba Dongar carbonatite alkaline complex at Cretaceous Tertiary boundary: evidence 40Ar 39 ArProceedings Indian Academy of Science, Vol. 109, No. 1, March pp. 39-47.IndiaCarbonatite, Geochronology
DS2000-0802
2000
Ray, J.S.Ray, J.S., Ramesh, R., Pande, Trivedi, Shukla, PatelIsotope and rare earth element chemistry of carbonatite alkaline complexes of Deccan volcanic: implications...Journal of Asian Earth Science, Vol. 18, No.2, Apr. pp.177-94.India, Gujarat, WesternCarbonatite, Magmatism, alteration
DS2000-0803
2000
Ray, J.S.Ray, J.S., Trivedi, J.R., Dayal, A.M.Strontium isotope systematics of Amba Dongar and Sung Valley carbonatite alkaline complexes, India: evidenceJournal of Asian Earth Science, Vol. 18, No. 5, Apr. pp. 585-94.IndiaCarbonatite, Crustal contamination - liquid immiscibility
DS2000-0804
2000
Ray, J.S.Ray, J.S., Trivedi, J.R., Dayal, A.M.Strontium isotope systematics of Amba Dongar and Sung Valley carbonaite - alkaline complexes: liquid immisc.Journal of Asian Earth Science, Vol. 18, No.5, Apr. pp.585-94.India, Gujarat, WesternCarbonatite, Liquid immiscibility, crustal contamination, mantle
DS2003-1136
2003
Ray, J.S.Ray, J.S., Pande, K., Pattanavak, S.K.Evolution of the Amba Donar carbonatite complex: constraints from 40 Ar 39 ArInternational Geology Review, Vol. 45, 9, pp. 857-62.IndiaCarbonatite, geochronology
DS2003-1137
2003
Ray, J.S.Ray, J.S., Pande, K., Pattanayak, S.K.Evolution of the Amba Dongar carbonatite complex: constraints from 40 Ar 39 ArInternational Geology Review, Vol. 45, 9, Sept. pp.875-62.India, Chhota UdaipurCarbonatite
DS200412-1636
2003
Ray, J.S.Ray, J.S., Pande, K., Pattanayak, S.K.Evolution of the Amba Dongar carbonatite complex: constraints from 40 Ar 39 Ar chronologies of the inner basalt and an alkalineInternational Geology Review, Vol. 45, 9, Sept. pp.875-62.India, Chhota UdaipurCarbonatite
DS200512-0892
2005
Ray, J.S.Ray, J.S., Pattanayak, S.K., Pande, K.Rapid emplacement of the Kerguelen plume related Syihet Traps, eastern India: evidence from 40 Ar 39 Ar geochronology.Geophysical Research Letters, Vol. 32, L10303.IndiaGeochronology
DS200512-0893
2004
Ray, J.S.Ray, J.S., Shukla, P.N.Trace element geochemistry of Amba Dongar carbonatite complex, India: evidence for fractional crystallization and silicate carbonate melt immiscibility.Proceedings National Academy of Sciences India , Vol. 113, 4, pp. 519-531.India, AsiaCarbonatite
DS200812-0942
2008
Ray, J.S.Ray, J.S.Geochemistry of Newania dolomite carbonatite, Rajasthan, India.Goldschmidt Conference 2008, Abstract p.A779.IndiaCarbonatite
DS200812-0943
2008
Ray, J.S.Ray, R., Shukia, A.D., Sheth, H.C., Ray, J.S., Duraiswami, Vanderkluysen, Rautela, MallikHighly heterogeneous Precambrian basement under the central Deccan Traps, India: direct evidence from xenoliths in dykes.Gondwana Research, Vol. 13, 3, pp. 375-385.IndiaPetrology - dykes
DS200912-0613
2009
Ray, J.S.Ray, J.S.Radiogenic isotopic ratio variations in carbonatites and associate alkaline silicate rocks: role of crustal assimilation.Journal of Petrology, Vol. 50, 10, October, pp. 1955-1971.MantleCarbonatite
DS200912-0614
2009
Ray, J.S.Ray, J.S.Radiogenic isotopic ratio variations in carbonatites and associated alkaline silicate rocks: role of crustal assimilation.Journal of Petrology, Vol. 50, 10, pp. 1955-1971.MantleCarbonatite
DS200912-0615
2009
Ray, J.S.Ray, J.S., Shulka, A.D., Dewangan, L.K.Carbon and oxygen isotopic compositions of Newania dolomite carbonatites, Rajasthan, India: implications for source of carbonatites.Mineralogy and Petrology, In press available ( 18p.)IndiaCarbonatite
DS201012-0614
2010
Ray, J.S.Ray, J.S., Shukia, A.D., Dewangan, L.K.Carbon and oxygen isotopic compositions of Newania dolomite carbonatites, Rajasthan India: implications for source of carbonatites.Mineralogy and Petrology, Vol. 98, 1-4, pp. 269-282.IndiaCarbonatite
DS201312-0736
2013
Ray, J.S.Ray, J.S., Pnde, K., Bhutani, R., Shukla, A.D., Rai, V.K., Kumar, A., Awasthi, N., Smitha, R.S., Panda, D.K.Age and geochemistry of the Newania dolomite carbonatites, India: implications for the source of primary carbonatite magma.Contributions to Mineralogy and Petrology, Vol. 166, 6, pp. 1613-1632.IndiaCarbonatite
DS201801-0016
2017
Ray, J.S.Gautam, I., Bhutani, R., Balakrishnan, S., Chatterjee, A., George, B.G., Ray, J.S.142Nd/144Nd of alkaline magmas in Phenai Mat a complex, Chhota Udaipur, Deccan flood basalt province.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 14.Indiaalkaline rocks

Abstract: The 65 million year old alkaline plug at Phenai Mata Complex, in Chota Udaipur sub province, is often linked to the last pulse of the Deccan volcanism. However, many believe that the Deccan-Reunion mantle plume that was responsible for the generation of flood basalts might not have been the source of Phenai Mata. It, however, could have acted as a heat source for these magmas derived from the subcontinentallithospheric- mantle (SCLM). Since the SCLM is generally considered to be a nonconvective mantle domain it has the potential to preserve some of the geochemical evidence of the early silicate Earth differentiation, e.g., 142Nd anomaly. In search of such signatures we analysed alkali basalts from the complex for their 142Nd/144Nd using high precision thermal ionization mass spectrometry. Whereas the geochemical characterization of these samples confirmed the lithospheric origin of their source magmas, their ? 142Nd compositions are found to be normal with respect to terrestrial standards. We infer that either the mantle source of Phenai Mata does not represent a true non-convective mantle or it is too young to retain any evidence of 146Sm decay.
DS1990-1334
1990
Ray, K.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
DS1970-0003
1970
Ray, L.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
DS2003-1138
2003
Ray, L.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granite province: evidence from southern IndiaJournal of Geophysical Research, Vol. 108, B2, 10.1029/2001JB000688IndiaUHP
DS2003-1139
2003
Ray, L.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granulite province: evidence from southernJournal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP, Geothermometry
DS200412-1637
2003
Ray, L.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., Rao, R.U.M.High mantle heat flow in a Precambrian granulite province: evidence from southern India.Journal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP Geothermometry
DS201606-1106
2016
Ray, L.Ray, L., Nagaraju, P., Singh, S.P., Ravi, G., Roy, S.Radioelemental, petrological and geochemical characterization of the Bundelk hand craton, central India: implication in the Archean geodynamic evolution.International Journal of Earth Sciences, Vol. 105, 4, pp. 1087-1107.IndiaNot specific to diamonds

Abstract: We have carried out radioelemental (232Th, 238U, 40K), petrological and geochemical analyses on granitoids and gneisses covering major rock formations of the Bundelkhand craton, central India. Our data reveal that above characteristics are distinct among granitoids (i.e. pink, biotite and grey granitoids) and gneisses (i.e. potassic and sodic types). Pink granitoid is K-feldspar-rich and meta-aluminous to per-aluminous in character. Biotite granitoid is meta-aluminous in character. Grey granitoid is rich in Na-feldspar and mafic minerals, granodiorite to diorite in composition and meta-aluminous in character. Among these granitoids, radioelements (Th, U, K) are highest in pink granitoid (45.0 ± 21.7 ppm, 7.2 ± 3.4 ppm, 4.2 ± 0.4 %), intermediate in biotite granitoid (44.5 ± 28.2 ppm, 5.4 ± 2.8 ppm, 3.4 ± 0.7 %) and lowest in grey granitoid (17.7 ± 4.3 ppm, 4.4 ± 0.6 ppm, 3.0 ± 0.4 %). Among gneisses, potassic-type gneisses have higher radioelements (11.8 ± 5.3 ppm, 3.1 ± 1.2 ppm, 2.0 ± 0.5 %) than the sodic-type gneisses (5.6 ± 2.8 ppm, 1.3 ± 0.5 ppm, 1.4 ± 0.7 %). Moreover, the pink granitoid and the biotite granitoid have higher Th/U (6 and 8, respectively) compared to the grey granitoid (Th/U: 4), implying enrichment of Th in pink and biotite granitoids relative to grey granitoid. K/U among pink, biotite and grey granitoids shows little variation (0.6 × 104, 0.6 × 104, 0.7 × 104, respectively), indicating relatively similar increase in K and U. Therefore, mineralogical and petrological data along with radioelemental ratios suggest that radioelemental variations in these lithounits are mainly related to abundances of the radioactive minerals that have formed by the fractionation of LILE from different magma sources. Based on present data, the craton can be divided into three distinct zones that can be correlated with its evolution in time and space. The central part, where gneisses are associated with metavolcanics of greenstone belt, is characterized by lowest radioelements and is the oldest component. The southern part, dominated by pink granitoid, is characterized by highest radioelements and is the youngest part. The northern part, dominated by grey and biotite granitoid, is characterized by moderate radioelements.
DS202202-0207
2021
Ray, L.Mukherjee, S., Ray, L., Maurya, S., Shalivahan, K.P.Nature of the lithosphere boundary beneath the eastern Dharwar craton of the Indian Shield.Journal of Asian Earth Sciences, in press available 10.1016/j.jseaes.2021.105701 46 p. PdfIndiaCraton

Abstract: The lithosphere-asthenosphere boundary (LAB) is a fundamental element of the plate tectonic hypothesis that accommodates the differential motion of rigid lithosphere over the weaker asthenosphere. In recent times, various usages have been used to define the LAB, depending on the nature of their measurements. Here, we investigate the lithospheric structure beneath the Eastern Dharwar Craton (EDC) of the Indian Shield using geochemical, thermal and seismological data sets. We analysed S-receiver functions from the stations deployed in the EDC along with the surface wave dispersion tomography. We also added thermal measurements from 5 different locations and geochemical data from 34 Kimberlite/Lamproite xenolith samples to constrain the nature of the LAB. The seismological measurements using Rayleigh wave dispersion and receiver function analysis indicate the lithospheric thickness of 98-118 and 94-118 km respectively, with sharp transition across the LAB. The P-T results from xenoliths are interpreted in concurrence with the heat-flow measurements suggesting a thick thermal lithosphere of ?200 km for the normal mantle solidus with cold geotherm. To reconcile our observations, we invoke partial melts or enriched in volatiles, which significantly lowers the viscosity of mantle rocks inducing a zone of weakness between the rigid lithosphere (?125km) and the convective asthenosphere. Further, we favour the view that the thick lithosphere beneath the Indian plate has been thinned by a plume during the Gondwanaland breakup at ?130Ma. The presence of younger kimberlites from the Indian shield support that it is further degenerated by the delamination leading to an uneven topography in the LAB.
DS1960-0389
1963
Ray, P.Ray, P.Geophysical Study of the Ferris OutlierRocky Mountain Association Geol. Field Conference 14th. Symposium, PP. 26-30.United States, State Line, Wyoming, Rocky MountainsKimberlite, Geophysics
DS200812-0943
2008
Ray, R.Ray, R., Shukia, A.D., Sheth, H.C., Ray, J.S., Duraiswami, Vanderkluysen, Rautela, MallikHighly heterogeneous Precambrian basement under the central Deccan Traps, India: direct evidence from xenoliths in dykes.Gondwana Research, Vol. 13, 3, pp. 375-385.IndiaPetrology - dykes
DS201906-1278
2019
Ray, S.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
Ray, S.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.
DS1994-1442
1994
Ray, T.W.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
DS1992-1635
1992
Rayden, L.H.Waschbusch, P.J., Rayden, L.H.Spatial and temporal evolution of foredeep basins: lateral strength variations and ineleastic yielding in continental lithosphereBasin Research, Vol. 4, No. 3/4, September/December pp. 179-196GlobalBasin evolution
DS2003-1140
2003
Raykova, R.B.Raykova, R.B., Nikolova, S.B.Anisotropy in the Earth's crust and uppermost mantle in southeastern Europe obtainedJournal of Applied Geophysics, Vol. 54, 3-4, pp. 247-256.MantleGeophysics - seismics
DS200412-1638
2003
Raykova, R.B.Raykova, R.B., Nikolova, S.B.Anisotropy in the Earth's crust and uppermost mantle in southeastern Europe obtained from Rayleigh and Love surface waves.Journal of Applied Geophysics, Vol. 54, 3-4, pp. 247-256.MantleGeophysics - seismics
DS201904-0791
2019
Raymakers, J.Vanpoucke, D.E.P., Nicely, S.S., Raymakers, J., Maes, W., Haenen, K.Can europium atoms form luminescent centres in diamond: a combined theoretical-experimental study.Diamond and Related Materials, https://doi.org/j. diamond.2019.02.024Globaldiamond morphology

Abstract: The incorporation of Eu into the diamond lattice is investigated in a combined theoretical-experimental study. The large size of the Eu ion induces a strain on the host lattice, which is minimal for the Eu-vacancy complex. The oxidation state of Eu is calculated to be 3+ for all defect models considered. In contrast, the total charge of the defect-complexes is shown to be negative: ?1.5 to ?2.3 electron. Hybrid-functional electronic-band-structures show the luminescence of the Eu defect to be strongly dependent on the local defect geometry. The 4-coordinated Eu substitutional dopant is the most promising candidate to present the typical Eu3+ luminescence, while the 6-coordinated Eu-vacancy complex is expected not to present any luminescent behaviour. Preliminary experimental results on the treatment of diamond films with Eu-containing precursor indicate the possible incorporation of Eu into diamond films treated by drop-casting. Changes in the PL spectrum, with the main luminescent peak shifting from approximately 614?nm to 611?nm after the growth plasma exposure, and the appearance of a shoulder peak at 625?nm indicate the potential incorporation. Drop-casting treatment with an electronegative polymer material was shown not to be necessary to observe the Eu signature following the plasma exposure, and increased the background luminescence.
DS201905-1083
2019
Raymakers, J.Vanpoucke, D.E.P., Nicley, S.S., Raymakers, J., Maes, W., Haenen, K.Can europium atoms form luminescent centres in diamond: a combined theoretical-experimental study.Diamond & Related Materials, Vol. 94, pp. 233-241.Globalluminescence

Abstract: The incorporation of Eu into the diamond lattice is investigated in a combined theoretical-experimental study. The large size of the Eu ion induces a strain on the host lattice, which is minimal for the Eu-vacancy complex. The oxidation state of Eu is calculated to be 3+ for all defect models considered. In contrast, the total charge of the defect-complexes is shown to be negative: ?1.5 to ?2.3 electron. Hybrid-functional electronic-band-structures show the luminescence of the Eu defect to be strongly dependent on the local defect geometry. The 4-coordinated Eu substitutional dopant is the most promising candidate to present the typical Eu3+ luminescence, while the 6-coordinated Eu-vacancy complex is expected not to present any luminescent behaviour. Preliminary experimental results on the treatment of diamond films with Eu-containing precursor indicate the possible incorporation of Eu into diamond films treated by drop-casting. Changes in the PL spectrum, with the main luminescent peak shifting from approximately 614?nm to 611?nm after the growth plasma exposure, and the appearance of a shoulder peak at 625?nm indicate the potential incorporation. Drop-casting treatment with an electronegative polymer material was shown not to be necessary to observe the Eu signature following the plasma exposure, and increased the background luminescence.
DS1998-0207
1998
Raymond, C.Cande, S.C., Stock, J., Raymond, C., Muller, R.D.New constraints on plate tectonic puzzle of the southwest PacificEos, Vol. 79, No. 7, Feb. 17, pp. 81-2.Australia, AntarcticaTectonics
DS1860-1003
1897
Raymond, H.Raymond, H.B.i. Barnato, a MemoirLondon: Isbister., 208P.Africa, South Africa, Cape ProvinceBiography
DS201012-0352
2009
Raymond, J.Kgaswane, E., Nyblade, A.A., Jordi, J., Durrheim, P.H.G.M., Raymond, J., Payanos, M.E.Shear wave velocity structure of the lower crust in southern Africa: evidence for compositional heterogeneity within Archean and Proterozoic terrains.Journal of Geophysical Research, Vol. 114, B12, B12304.AfricaGeophysics - seismics
DS200512-0894
2005
Raymond, M.J.Raymond, M.J., Gudmundsson, G.H.On the relationship between surface and basal properties on glaciers, ice sheets, and ice streams.Journal of Geophysical Research, Vol. 110, B8, pp. B08411 10.1029/2005 JB003681TechnologyGeomorphology
DS200612-1139
2005
Raymond, M.J.Raymond, M.J., Gudmundsson, G.H.On the relationship between surface and basal properties on glaciers, ice sheets and ice streams.Journal of Geophysical Research, Vol. 110, B8, BO8411.GlobalGeomorphology
DS1998-1219
1998
Raymond, O.Raymond, O., Sun, S.S.A comparison of Ordovician and Devonian magmatism in the eastern Lach lanfold belt: re-eval. explorationAgso Research Newsletter, No. 28, May pp. 8-10AustraliaVolcanics, magmatism, Geochronology
DS1860-0214
1873
Raymond, R.W.Raymond, R.W.Have We Diamonds in California?Statistics of Mines And Mining In The States And Territories, PP. 27-28.United States, CaliforniaDiamond Occurrence
DS1860-0215
1873
Raymond, R.W.Raymond, R.W.A Report upon the Mineral Resources of the States and Territories West of the Rocky Mountains for the Year 1871U.s. Treasury Department, 566P.United States, CaliforniaDiamond Occurrence
DS1860-0237
1874
Raymond, R.W.Raymond, R.W.Remarks on the Occurrence of South African DiamondsAmerican Institute of Mining and Metallurgy. Transactions, Vol. 2, PP. 143-144.Africa, South Africa, Cape ProvinceGeology
DS1860-0253
1875
Raymond, R.W.Raymond, R.W.DiamondsStatistics of Mines And Mining In The States And Territories, HOUSE EXECUTIVE DOCUMENT 177, P. 150.United States, CaliforniaDiamond Occurrence
DS201212-0488
2012
Raymond, S.N.Morbidelli, A., Lunine, J.I., O'Brien, D.P., Raymond, S.N., Walsh, K.J.Building terrestrial planets.Annual Review of Earth and Planetary Sciences, Vol. 40, pp. 251-275.MantleTectonics
DS202101-0026
2020
Raynaud, V.Pardieu, V., Sangsawong, S., Cornuz, L., Raynaud, V., Luetrakulprawat, S.Update on emeralds from the Mananjary-Irondo area, Madagascar.Journal of Gemology, Vol. 37, 4, pp. 416-425.Africa, Madagascaremerald
DS2000-0805
2000
Rayner, J.G.Rayner, J.G., Napier-Munn, T.J.The mechanism of magnetics capture in the wet drum magnetic separatorMinerals Eng., Vol. 13, No. 3, pp. 277-85.GlobalMineral processing - DMS
DS2003-1141
2003
Rayner, J.G.Rayner, J.G., Napier-Munn, T.J.A mathematical model of concentrate solids content for the wet drum magneticInternational Journal of Mineral Processing, Vol. 70, 1-4. June pp. 53-65.GlobalTechnology - dense media, low concentrate density
DS2003-1142
2003
Rayner, J.G.Rayner, J.G., Napier-Munn, T.J.A mathematical model of recovery of dense medium magnetics in the wet drumInternational Journal of Mineral Processing, Vol. 69, 1-4, March pp. 157-173.GlobalTechnology - magnetic separator, DMS, ferrosilicon, mag
DS200412-1639
2003
Rayner, J.G.Rayner, J.G., Napier-Munn, T.J.A mathematical model of concentrate solids content for the wet drum magnetic separator.International Journal of Mineral Processing, Vol. 70, 1-4. June pp. 53-65.TechnologyTechnology - dense media, low concentrate density
DS1930-0167
1934
Rayner, J.M.Kenny, E.J., Rayner, J.M.Diamond Leads. V. Farrell, InverellNew South Wales Geological Survey Report., GS 1934/048, (UNPUBL.).Australia, New South WalesDiamond
DS201708-1745
2017
Rayner, M.Rayner, M.New insights into volcanic processes and diamond grades from deep mining at Argyle.11th. International Kimberlite Conference, OralAustraliaDeposit - Argyle
DS200912-0459
2009
Rayner, M.J.Luguet, A., Jaques, A.I., Pearson, D.G., Smith, C.B., Bulanova, G.P., Roffey, S.L., Rayner, M.J., Lorand, J.P.An integrated petrological, geochemical and Re-Os isotope study of peridotite xenoliths from the Argyle lamproite, western Australia and implications forLithos, In press available, 64p.AustraliaGeochronology - Cratonic diamond occurrences
DS201804-0674
2017
Rayner, M.J.Boxer, G.L., Jaques, A.L., Rayner, M.J.Argyle ( AK1) diamond deposit.Australian Ore Deposits, AusIMM Monograph 32, ed. Phillips, N., pp. 527-532.Australiadeposit - Argyle
DS201809-2078
2018
Rayner, M.J.Rayner, M.J., Moss, S.W., Lorenz, V., Jaques, L., Boxer, G.L., Smith, C.B., Webb, K.New insights into volcanic processes from deep mining of the southern diatreme within the Argyle lamproite pipe, Western Australia.Mineralogy and Petrology, doi.org/10.1007/ s00710-018-0625-4 13p.Australia, Western Australiadeposit - Argyle

Abstract: Underground mining and deep drilling of the richly diamondiferous ~1.2 Ga Argyle lamproite in Western Australia has prompted a re-evaluation of the geology of the pipe. Argyle is considered to be a composite pipe that formed by the coalescence of several diatremes and has been offset and elongated by post-emplacement faulting. Recent geological studies have recognised at least five distinct volcaniclastic lamproite lithofacies with differing diamond grades. The new data suggest that the centre of the southern (main) diatreme is occupied by well-bedded, olivine lamproite lapilli tuff with very high diamond grades (>10 ct/t). Characteristic features include a clast-supported fabric and high modal abundance of densely packed lamproite lapilli and coarse-grained, likely mantle-derived olivine now replaced by serpentine and/or talc. The persistence of small-scale graded and cross-bedding in this lithofacies to depths of ~1.5 km below the original surface prior to erosion suggests phreatomagmatic volcanism forming the diatreme was syn-eruptively accompanied by subsidence of the tephra, maintaining a steep-walled diatreme in the water-saturated country rock sediments.
DS201812-2797
2018
Rayner, M.J.Das, H., Kobussen, A.F., Webb, K.J., Phillips, D., Maas, R., Soltys, A., Rayner, M.J., Howell, D.Bunder deposit: The Bunder diamond project, India: geology, geochemistry, and age of Saptarshi lamproite pipes.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 201-222.Indiadeposit - Bunder
DS201812-2869
2018
Rayner, M.J.Rayner, M.J., Jaques, A.L., Boxer, G.L., Smith, C.B., Lorenz, V., Moss, S.W., Webb, K., Ford, D.Argyle deposit: The geology of the Argyle ( AK1) diamond deposit, western Australia.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 89-118.Australia, western Australiadeposit - Argyle
DS201812-2875
2018
Rayner, M.J.Roffey, S., Rayner, M.J., Davy, A.T., Platell, R.W.Argyle deposit: Evaluation of the AK1 deposit at Argyle diamond mine.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 65-88.Australia, western Australiadeposit - Argyle
DS2003-1063
2003
Rayner, N.Percival, J.A., Stern, R.A., Rayner, N.Archean adakites from the Ashuanipi complex, eastern Superior Province Canada:Contributions to Mineralogy and Petrology, Vol. 145, 3, pp. 265-80.OntarioBlank
DS200412-1525
2003
Rayner, N.Percival, J.A., Stern, R.A., Rayner, N.Archean adakites from the Ashuanipi complex, eastern Superior Province Canada: geochemistry, geochronology and tectonic significContributions to Mineralogy and Petrology, Vol. 145, 3, pp. 265-80.Canada, OntarioTectonics
DS200612-1140
2005
Rayner, N.Rayner, N., Stott, G.M.Discrimination of Archean domains in the Sachigo Subprovince: a progress report on the geochronology.Ontario Geological Survey Summary of Field Work, Open File, 6172, pp. 10-1-10-21.Canada, OntarioGeochronology
DS200812-0998
2008
Rayner, N.Sanborn-Barrie, M., Chakungal, J., James, D.T., Whalen, J., Rayner, N., Berman, R.G., Craven, J., Coyle, M.New understanding of the geology and diamond prospectivity of Southampton Island, central Nunavut.Northwest Territories Geoscience Office, p. 53-54. abstractCanada, NunavutDeposit - Qilalugaq
DS201312-0563
2013
Rayner, N.Machado, G., Bilodeau, C., Takpanie, R., St.Onge, M., Rayner, N., Skipton, D., From, R., MacKay, C., Young, M., Creason, G., Braden, Z.Regional bedrock mapping, Hall Peninsula, Nunavut.Geoscience Forum 40 NWT, abstract only p. 26Canada, NunavutMapping
DS2002-0152
2002
Rayner, N.M.Bickford, M.E., Rayner, N.M., Stern, R.A.Exotic origin of the Saskatchewan Craton, Trans Hudson oroegn, revealed by new SHRIMP zirocin U Pb ages,Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.10., p.10.SaskatchewanGeochronology
DS2002-0153
2002
Rayner, N.M.Bickford, M.E., Rayner, N.M., Stern, R.A.Exotic origin of the Saskatchewan Craton, Trans Hudson oroegn, revealed by new SHRIMP zirocin U Pb ages,Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.10., p.10.SaskatchewanGeochronology
DS200512-0895
2005
Rayner, N.M.Rayner, N.M., Stern, R.A., Bickford, M.E.Tectonic implications of new SHRIMP and TIMS U Pb geochronology of rocks from the Sask Craton, Peter Lake Domain and Hearne margin, Trans-Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 635-657.Canada, SaskatchewanGeochronology
DS1992-1261
1992
Rayner, N.W.Rayner, N.W., Tays, R.H., Lawton, S.E.New mining legislation in CanadaPda Seminar, Held April 2, 1992, 160p. $ 45.00CanadaLegal, Mining legislation seminar notes
DS1991-1401
1991
Rayner, R.J.Rayner, R.J., Waters, S.B., McKay, I.J., Dobss, P.N., Shaw, A.L.The mid-Cretaceous paleoenvironment of central Southern Africa ( Orapa, Botswana)Paleogeography, Paleoclimatology, Paleoecology, Vol. 88, pp. 147-156BotswanaPaleoenvironment, Orapa
DS1991-1267
1991
Rayner, S.O'Riordan, T., Rayner, S.Risk management for global environmental changeGlobal Environmental Change, March pp. 91-108GlobalEnvironment, Economics
DS1986-0791
1986
Raynor, L.R.Sutherland, F.L., Hollis, J.D., Raynor, L.R.Diamonds from nepheline mugearite- a discussion of garnet web sterites and associated ultramafic inclusions from nepheline mugearite in the Malcha area New South WalesAustMineralogical Magazine, Vol. 49, No. 354, December pp. 748-751Australia, New South WalesInclusions
DS1986-0792
1986
Raynor, L.R.Sutherland, F.L., Raynor, L.R., Hollis, J.D., Temby, P.A.Prospective relationships between diamonds, volcanism and tectonisMProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 484-486AustraliaDiamond exploration, New South Wales
DS1991-1678
1991
Raynor, L.R.Sutherland, F.L., Temby, P., Hollis, J.D., Raynor, L.R.Anomalous hosts, unusual characters and the role of hot and cool geothermsfor east Australian diamond sourcesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 398-400AustraliaBasalts, Copeton, Bingara, Walcha, Airly Mt, Diamond morphology
DS1993-1556
1993
Raynor, L.R.Sutherland, F.L., Raynor, L.R.Peepholes into crust-mantle sections below New England Orogen, EasternAustralia.The Xenolith window into the lower crust, abstract volume and workshop, p. 21.AustraliaMantle, Xenoliths
DS1994-1722
1994
Raynor, L.R.Sutherland, F.L., Raynor, L.R., Pogson, R.E.Spinel to garnet lherzolite transition in relation to high temperaturepaleogeotherms, eastern Australia.Australian Journal of Earth Sciences, Vol. 41, No. 3, June pp. 205-220.AustraliaGeothermometry, Lherzolite, xenoliths
DS1994-1723
1994
Raynor, L.R.Sutherland, F.L., Temby, P., Raynor, L.R., Hollis, J.D.A review of the east Australian diamond provinceProceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 170-186.AustraliaDiamond, Review
DS200412-1952
2004
Raynor, L.R.Sutherland, F.L., Hollis, J.D., Birch, W.D., Fogson, R.E., Raynor, L.R.Cumulate rich xenolith suite in Late Cenozoic basaltic eruptives Hepburn Lagoon, Newlyn in relation to western Victorian lithospAustralian Journal of Earth Sciences, Vol. 51, 3, June pp. 319-338.AustraliaXenoliths
DS200512-1066
2004
Raynor, L.R.Sutherland, F.L., Hollis, J.D., Birch, W.D., Pogson, R.E., Raynor, L.R.Cumulate rich xenolith suite in Late Cenozoic basaltic eruptives, Hepburn Lagoon, Newlyn in relation to western Victorian lithosphere.Australian Journal of Earth Sciences, Vol. 51, 3, pp. 319-337.Australia, VictoriaXenoliths
DS2002-0579
2002
Raza, A.Gleadow, A.J., Kohn, B.P., Brown, R.W., O'Sullivan, P.B., Raza, A.Fission track thermotectonic imaging of the Australian continentTectonophysics, Vol. 349, No. 1-4, pp. 5-21.AustraliaGeothermometry
DS200712-0452
2006
Raza, A.Hu, S., Raza, A., Min, K., Kohn, B.P., Reiners, Ketcham, Wang, GleadowLate Mesozoic and Cenozoic thermotectonic evolution along a transect from the north Chin a craton through the Qinling orogen into the Yangtze craton, central.Tectonics, Vol. 25, 6, TC6009ChinaGeothermometry
DS200712-0878
2007
Raza, M.Raza, M., Khan, M., Azam, M.Plate plume accretion tectonics in Proterozoic terrain of north eastern Rajasthan India: evidence from mafic volcanic rocks of north Delhi fold belt.Island Arc, Vol. 16, 4, pp. 536-552.IndiaTectonics
DS200812-0007
2008
Raza, M.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
DS2000-0166
2000
Razakamana, T.Collins, A.S., Kroner, A., Razakamana, T., Windley, B.F.The tectonic architecture of the East African Orogen in central Madagascar: a structural and geochronologicalJournal of African Earth Sciences, p. 21. abstract.MadagascarTectonics, Geochronology
DS200412-0345
2003
Razakamana, T.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
DS201904-0715
2019
Razakamana, T.Armistead, S.E., Collins, A.S., Redaa, A., Gilbert, S., Jepson, G., Gillespie, J., Blades, M.L., Foden, J.D., Razakamana, T.Structural evolution and medium temperature thermochronology of central Madagascar: implications for Gondwana amalgamation.Journal of the Geological Society of London, in press available 25p.Africa, Madagascarthermochronology

Abstract: Madagascar occupied an important place in the amalgamation of Gondwana, and preserves a record of several Neoproterozoic events that can be linked to orogenesis of the East African Orogen. We integrate remote sensing and field data to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic foliation (S1), followed by south to south-west directed, tight to isoclinal, recumbent folding (D2). These are overprinted by north-trending upright folds that formed during a ~E-W shortening event. Together these produced type 1 and type 2 fold interference patterns throughout the Itremo and Ikalamavony domains. Apatite U-Pb and muscovite and biotite Rb-Sr thermochronometers indicate that much of central Madagascar was thermally reset to at least ~500oC at c. 500 Ma. Deformation in west-central Madagascar occurred between c. 750 Ma and c. 550 Ma, and we suggest this deformation formed in response to the c. 650 Ma collision of Azania with Africa along the Vohibory Suture in southwestern Madagascar. In eastern Madagascar, deformation is syn- to post-550 Ma, which formed in response to the final closure of the Mozambique Ocean along the Betsimisaraka Suture that amalgamated Madagascar with the Dharwar Craton of India.
DS200712-0494
2007
Razakamanana, T.Jons, N., Schenk, V., Razakamanana, T.Polymetamorphic evolution of ultrahigh temperature granulites from southern Madagascar: implications for the amalgamation of Gondwana.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 256-257.Africa, MadagascarTectonics
DS200712-0495
2007
Razakamanana, T.Jons, N., Schenk, V., Razakamanana, T.Polymetamorphic evolution of ultrahigh temperature granulites from southern Madagascar: implications for the amalgamation of Gondwana.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 256-257.Africa, MadagascarTectonics
DS201312-0615
2013
Razakamanana, T.Moteani, G., Kostitsyn, Y.A., Gilg, H.A., Preinfalk, C., Razakamanana, T.Geochemistry of phlogopite, diopside, calcite, anhydrite and apatite pegmatites and syenites of southern Madagascar: evidence for crustal silicocarbonatitic (CSC) melt formatio in a Panafrican collisional tectonic setting.International Journal of Earth Sciences, Vol. 102, 3, pp. 627-645.Africa, MadagascarCarbonatite
DS201509-0423
2014
Razakamanana, T.Ratheesh-Kumar, R.T., Ishwar-Kumar, C., Windley, B., Razakamanana, T., Nair, R.R., Sajeev, K.India-Madagascar paleo-fit based on flexural isostasy of their rifted margins.Gondwana Research, Vol. 28, 2, pp. 581-600.India, Africa, MadagascarTectonics

Abstract: The present study contributes new constraints on, and definitions of, the reconstructed plate margins of India and Madagascar based on flexural isostasy along the Western Continental Margin of India (WCMI) and the Eastern Continental Margin of Madagascar (ECMM). We have estimated the nature of isostasy and crustal geometry along the two margins, and have examined their possible conjugate structure. Here we utilize elastic thickness (Te) and Moho depth data as the primary basis for the correlation of these passive margins. We employ the flexure inversion technique that operates in spatial domain in order to estimate the spatial variation of effective elastic thickness. Gravity inversion and flexure inversion techniques are used to estimate the configuration of the Moho/Crust-Mantle Interface that reveals regional correlations with the elastic thickness variations. These results correlate well with the continental and oceanic segments of the Indian and African plates. The present study has found a linear zone of anomalously low-Te (1-5 km) along the WCMI (~1680 km), which correlates well with the low-Te patterns obtained all along the ECMM. We suggest that the low-Te zones along the WCMI and ECMM represent paleo-rift inception points of lithosphere thermally and mechanically weakened by the combined effects of the Marion hotspot and lithospheric extension due to rifting. We have produced an India-Madagascar paleo-fit representing the initial phase of separation based on the Te estimates of the rifted conjugate margins, which is confirmed by a close-fit correlation of Moho geometry and bathymetry of the shelf margins. The matching of tectonic lineaments, lithologies and geochronological belts between India and Madagascar provide an additional support for the present plate reconstruction.
DS202103-0367
2021
Razakamanana, T.Armistad, S.E., Collins, A.S., Schmitt, R.S., Costa, R.L., De Waele, B., Razakamanana, T., Payne, J.L., Foden, J.D.Proterozoic basin evolution and tectonic geography of Madagascar: implications for an East Africa connection during the Paleoproterozoic. ( zircon analyses link Tanzania craton and India)Tectonics, doi/epdf/10. 10292020Tc006498 Africa, Madagascarcraton

Abstract: Madagascar hosts several Paleoproterozoic sedimentary sequences that are key to unravelling the geodynamic evolution of past supercontinents on Earth. New detrital zircon U-Pb and Hf data, and a substantial new database of ?15,000 analyses are used here to compare and contrast sedimentary sequences in Madagascar, Africa and India. The Itremo Group in central Madagascar, the Sahantaha Group in northern Madagascar, the Maha Group in eastern Madagascar, and the Ambatolampy Group in central Madagascar have indistinguishable age and isotopic characteristics. These samples have maximum depositional ages > 1700 Ma, with major zircon age peaks at c. 2500 Ma, c. 2000 Ma and c. 1850 Ma. We name this the Greater Itremo Basin, which covered a vast area of Madagascar in the late Paleoproterozoic. These samples are also compared with those from the Tanzania and the Congo cratons of Africa, and the Dharwar Craton and Southern Granulite Terrane of India. We show that the Greater Itremo Basin and sedimentary sequences in the Tanzania Craton of Africa are correlatives. These also tentatively correlate with sedimentary protoliths in the Southern Granulite Terrane of India, which together formed a major intra?Nuna/Columbia sedimentary basin that we name the Itremo?Muva?Pandyan Basin. A new Paleoproterozoic plate tectonic configuration is proposed where central Madagascar is contiguous with the Tanzania Craton to the west and the Southern Granulite Terrane to the east. This model strongly supports an ancient Proterozoic origin for central Madagascar and a position adjacent to the Tanzania Craton of East Africa.
DS2003-0265
2003
Razakamananan, T.Collins, A.S., Fitzimons, I.C., Hulscher, B., Razakamananan, T.Structure of the eastern margin of the East African Orogen in central MadagascarPrecambrian Research, Vol. 123, 2-4, pp.111-133.MadagascarBlank
DS200412-0344
2003
Razakamananan, T.Collins, A.S., Fitzimons, I.C., Hulscher, B., Razakamananan, T.Structure of the eastern margin of the East African Orogen in central Madagascar.Precambrian Research, Vol. 123, 2-4, pp.111-133.Africa, MadagascarTectonics
DS202010-1826
2020
RazakMnN, T.Armistead, S.E., Collins, A.S., Redaa, A., Jepson, G., Gillespie, J., Gilbert, S., Blades, M.L., Foden, J.D., RazakMnN, T.Structural evolution and medium temperature thermochronology of central Madagascar: implications for Gondwana amalagamation.Journal of the Geological Society, Vol. 177, pp. 784-798.Africa, Madagascargeothermometry

Abstract: Madagascar occupied an important place in the amalgamation of Gondwana and preserves a record of several Neoproterozoic events that are linked to orogenesis of the East African Orogen. In this study, we integrate remote sensing, field data and thermochronology to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic foliation (S1), followed by south- to SW-directed, tight to isoclinal, recumbent folding (D2). These are overprinted by north-trending upright folds that formed during an approximately east-west shortening event (D3). Together these produced type 1 and type 2 fold interference patterns throughout the Itremo and Ikalamavony domains. We show that the Itremo and Ikalamavony domains were deformed together in the same orogenic system, which we interpret as the c. 630 Ma collision of Azania with Africa along the Vohibory Suture in southwestern Madagascar. In eastern Madagascar, deformation is syn- to post-550 Ma, and probably formed in response to final closure of the Mozambique Ocean along the Betsimisaraka Suture that amalgamated Madagascar with the Dharwar Craton of India. Apatite U-Pb and novel laser ablation triple quadrupole inductively coupled plasma mass spectrometry (LA-QQQ-ICP-MS) muscovite and biotite Rb-Sr thermochronology indicates that much of central Madagascar cooled through c. 500°C at c. 500 Ma.
DS1997-0414
1997
Razandranorosoa, D.Girard, J.P., Razandranorosoa, D., Freyssinet, P.Laser oxygen isotope analysis of weathering goethite from the lateritic profile of Yaou: paleoclimatic..Applied Geochemistry, Vol. 12, No. 2, March, 1, pp. 163-174French GuianaLaterites, Geochronology
DS202105-0786
2021
Razgulov, A.A.Razgulov, A.A., Lyanpin, S.G., Novikov, A.P., Ekimov, E.A.Low-temperature photoluminescence study of SnV centers in HPHT diamond.Diamond & Related Materials, Vol. 116, 108379 9p. PdfGlobaldiamond colours

Abstract: Here we report on the study of temperature shift and broadening of the zero phonon line (ZPL) of SnV center in HPHT microcrystalline diamond in the temperature range of 80-300 K. To separate contributions of lattice thermal expansion and electron-phonon coupling, the study of the pressure effect on the ZPL was conducted. A strong nonlinearity observed in the electron-phonon part of the ZPL temperature shift appeared to be in good agreement with well-known polynomial law ?E(T) = cT^2-dT^4 and, therefore, can be related to the effect of the strong softening of elastic springs.
DS201412-0460
2014
Razink, J.J.Kinzie, C.R., Que Hee, S.S., Stich, A., Tague, K.A., Mercer, C., Razink, J.J., Kennett, D.J., DeCarli, P.S., Bunch, T.E., Wittke, J.H., Israde-Alcantara, I., Bischoff, J.L., Goodyear, A.C., Tankersley, K.B., Kimbel, D.R., Culleton, B.J., Erlandson, J.M.Nanodiamond rich layer across three continents consistent with major cosmic impact at 12,800 Cal BP Journal of Geology, Vol 122, 5, pp. 475-506.Global, GreenlandNanodiamonds
DS201502-0069
2014
Razink, J.J.Kinzie, C.R., Que Hee, S.S., Stich, A., Tague, K.A., Mercer, C., Razink, J.J., Kennett, D.J., DeCarli, P.S., Bunch, T.E., Wittke, J.H., Israde-Alantara, I., Bischoff, J.L., Goodyear, A.C., Tankersley, K.B., Kimbel, D.R., Culleton, B.J., Erlandson, J.M.Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 Cal BP.Journal of Geology, Vol. 122, Sept. pp. 475-506.South America, BrazilNanodiamonds
DS201604-0590
2015
Razinkov, E.A.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.
DS201608-1437
2016
Raznitsin, Yu.N.Savelieva, G.N., Raznitsin, Yu.N., Merkulova, M.V.Metamorphsm of peridotites in the mantle wedge above the subduction zone: hydration of the lithospheric mantle.Doklady Earth Sciences, Vol. 468, 1, pp. 438-440.Russia, Polar UralsSubduction

Abstract: Two areas with different types of hydration (serpentinization), which occurred in two settings distinct in temperatures, pressures, and stresses, are spatially individualized in the ophiolitic ultramafic massifs of the Polar Urals. The high-temperature hydration of ultramafic rocks occurred in the lithosphere of the mantle wedge directly above the subducted slab. The initial conditions of hydration are limited to 1.2-2 GPa and 650-700°C; a stable assemblage of olivine + antigorite + magnetite ? amphibole ? talc ? chlorite was formed at 0.9-1.2 GPa and 550-600°C. The low-temperature mesh lizardite-chrysotile serpentinization occurred in the crustal, near-surface conditions. Both types of hydration were accompanied by release of hydrogen, which participates in abiogenic CH4 synthesis in the presence of CO2 dissolved in water.
DS1960-0390
1963
Razumikhin, N.V.Razumikhin, N.V.Repartition des Diamants dans Les Profils Longitudinal et Transversal des Placers.Chron. Des Mines De la Recherche Miniere., 31ST. ANNEE, No. 316, PP. 46-47.RussiaAlluvial, Diamond, Placers
DS200912-0765
2009
Razumov, A.N.Tolstov, A.V., Minin, V.A., Vasilenko, V.B., Kuznetsova, L.G., Razumov, A.N.A new body of highly Diamondiferous kimberlites in the Nakyn field of the Yakutian kimberlite province.Russian Geology and Geophysics, Vol. 50, 3, pp. 162-173.RussiaMineral chemistry
DS201506-0276
2015
Razumov, A.N.Ignatov, P.A., Novikov, K.V., Shmonov, A.M., Razumov, A.N., Kilizhikov, O.K.Comparative analysis of ore-bearing structures in Maiskoe, Markha and Ozernoe kimberlite bodies at the Nakyn Field, Yakutia.Geology of Ore Deposits, Vol. 57, 2, pp. 111-117.RussiaDeposit - Nakyn
DS201507-0317
2015
Razumov, A.N.Ignaov, P.A., Novikov, K.V., Shmonov, A.M., Razumov, A.N., Kilizhikov, O.K.Comparative analysis of ore bearing structures in Maiskoe, Markha and Ozernoe kimberlite bodies at the Nakyn field, Yakutia.Geology of Ore Deposits, Vol. 57, 2, pp. 111-117.RussiaDeposit - Nakyn
DS201809-2040
2018
Razumov, A.N.Ignatov, P.A., Novikov, K.V., Shmonov, A.M., Zaripov, N.R., Khodnya, M.S., Razumov, A.N., Kilishekov, O.K., Kryazhev, S.G., Kovalchuk, O.E.Zoning of faults and secondary mineralization of host rocks of kimberlites of the Maiscoe diamond deposit, Nakyn field, Yakutia.Geology of Ore Deposits, Vol. 60, 3, pp. 201-209.Russiadeposit - Maiscoe
DS1991-1402
1991
Razvalyaev, A.V.Razvalyaev, A.V.Continental rift formation and its prehistoryA.a. Balkema, 206p. approx. $ 50.00Red SeaTectonics, Arabian-Nubian shield, Book -ad
DS1986-0846
1986
Razvozzhaeva, E.A.Vorontsov, A.E., Razvozzhaeva, E.A., Syngaevskii, E.D., KhlebnikovaGeochemical characteristics of carbonaceous matter from diatremes of the Siberian Platform*(in Russian)Geochemistry International (Geokhimiya), (Russian), No. 2, pp. 226-235RussiaBitumens
DS2002-1315
2002
Razvozzhaeva, E.A.Razvozzhaeva, E.A., Prokofev, Spiridonov, MartikhaevPrecious metals and carbonaceous substance in ores of the Sukhoi Log deposit, Eastern Siberia, Russia.Geology of Ore Deposits, Vol.44,2,pp. 103-110.RussiaGold, carbon, metallogeny, Deposit - Sukhoi Log
DS2002-1316
2002
Razzkazov, S.V.Razzkazov, S.V., Bowring, S.A., Hawsh, T., Demonterova, E.I., Logachev, N.A.The Pb Nd and Sr isotope systematics in heterogeneous continental lithosphere aboveDoklady Earth Sciences, Vol. 387A, 9. pp. 1056-9.MantleGeochronology, Convection
DS1995-1553
1995
RBC Dominion SecuritiesRBC Dominion SecuritiesDia Met Minerals - Canada's new diamond industryRbc Securities, 11p.Northwest TerritoriesNews item, Dia Met Minerals
DS1996-1168
1996
RBC Dominion SecuritiesRBC Dominion SecuritiesWhile the majority of Redaurum's diamond assets move from strength tostrength, there is concern River RanchRbc Securities, August 5.Colorado, Zimbabwe, South AfricaNews item, Redaurum Ltd.
DS201905-1072
2017
Re, G.Re, G.Evolution and dynamics of a monogenetic volcanic complex in the southern Hopi Buttes Volcanic Field: magma diversion and fragmentation processes at the Jgged Rocks Complex.Thesis: Phd Otago University, June United States, Arizonamagmatism

Abstract: Many populated areas in the world (e.g., Flagstaff, AZ; Auckland, NZ; Mexico City, MEX) lie within active monogenetic volcanic fields that typically contain small volcanic cones and explosive maar craters formed over the course of a single eruptive cycle. Although much work has focused on the eruptive behaviour of monogenetic volcanoes, little geological information exists about their subsurface development and how the movement of magma through Earth’s shallow crust modulates the location and style of hazardous volcanic eruptions. Determination of the dynamics of magma intrusion and the transition from a coherent magma's ascent to its explosive fragmentation is crucial to our understanding of the controls on explosive versus effusive eruptive behaviour, thus to better evaluation of risks in a certain area. This study aims to determine the processes and relative timing of activity that took place below the ground surface of the deeply-eroded but well-preserved Jagged Rocks Complex, a cluster of monogenetic volcanoes within the Miocene Hopi Buttes Volcanic Field in northeastern Arizona, by combining detailed structural mapping, volcanological observation, paleomagnetic and geochemical analysis. The Jagged Rocks Complex, exposed at ~ 350 m below the pre-eruptive surface, comprises a well-preserved intrusive network, including dikes, sills and inclined sheets, associated with different type of fragmental bodies including buds, pyroclastic massifs and a diatreme, that represent different extents of shallow-depth fragmentation. These exposures at the Jagged Rocks Complex provide an excellent natural laboratory for examining the subsurface record of volcano initiation, and for constraining interpretations of processes controlling upward migration of magma from intrusion to eruption. This multidisciplinary approach allows an investigation at different levels from the source region to the surface, and aims to shed the light on the processes that regulate eruptions not only within monogenetic volcanic fields but also within small basaltic volcanoes in general.
DS2002-1317
2002
Read, G.Read, G.The Superior search continues: an update of diamond activities on the Superior cratonProspectors and Developers Association of Canada (PDAC) 2002, 2p. abstractOntario, James Bay LowlandsGeology, overview, Navigator Resources
DS200412-1640
2004
Read, G.Read, G., Grutter, H., Winter, S., Luckman, N., Gaunt, F., Thomsen, F.Stratigraphic relations, kimberlite emplacement and lithospheric thermal evolution Quirico Basin, Minas Gerais State, Brazil.Lithos, Vol. 77, 1-4, Sept. pp. 803-818.South America, Brazil, Minas GeraisAreado, clinopyroxene, kamafugite, Mata da Corda, therm
DS200512-0896
2005
Read, G.Read, G.Bulk sampling the Star kimberlite, Saskatchewan.British Columbia & Yukon Mineral Exploration Roundup, Jan.24-27th., p. 82-83.Canada, SaskatchewanNews item - brief overview, Shore Gold
DS200512-0897
2005
Read, G.Read, G.Underground bulk sampling of the Star kimberlite, Saskatchewan.CIM Mining Rocks April 24-27th. Toronto Annual Meeting, Paper# 1947 AbstractCanada, SaskatchewanNews item - Shore Gold
DS200612-1141
2005
Read, G.Read, G.Star Diamond project.Prospectors and Developers Association of Canada, March 1p. abstractCanada, SaskatchewanHistory
DS200612-1142
2006
Read, G.Read, G.Conducting a prefeasibility on the Star kimberlite in central Saskatchewan.Roundup 06, Abstract p.70-71.Canada, SaskatchewanNews item - overview
DS200612-1143
2006
Read, G.Read, G.The Star kimberlite, Saskatchewan - pre-feasibility update.CIM Conference and Exhibition, Vancouver - Creating Value with Values, List of talks CIM Magazine, Feb. p. 77.Canada, SaskatchewanOverview - Shore Gold
DS200912-0285
2009
Read, G.Harvey, S., Kjarsgaard, McClintock, M., Shimell, M., Fourie, L., Du Plessis, P., Read, G.Geology and evaluation strategy of the Star and Orion South kimberlites, Fort a la Corne, Canada.Lithos, In press availableCanada, SaskatchewanDeposit - Star, Orion
DS201012-0179
2010
Read, G.Eccles, D.R., Read, G.Kimberlites and related rocks in the Western Canadian Sedimentary Basin. SHORT COURSE GAC MAY 14.GAC Short Course, Registration geocanada2010.caCanada, AlbertaShort Course
DS201212-0288
2012
Read, G.Harvey, S., Read, G., DesGagnes, B., Shimell, M., Danoczi, J., Van Breugel, B., Fourie, L., Stilling, A.Utilization of olivine macrocryst grain size and abundance dat a as a proxy for diamond size and grade in pyroclastic deposits of the Orion South kimberlite Fort a la Corne, Sasakatchewan, Canada.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, SaskatchewanDeposit - Orion South
DS201312-0367
2013
Read, G.Harvey, S., Read, G., DesGagnes, B., Shimell, M.Utilization of olivine macrocryst grain size and abundance dat a as a proxy for diamond size and grade in pyroclastic deposits of the Orion South kimberlite, Fort a la Corne, Saskatchewan, Canada.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 79-95.Canada, SaskatchewanDeposit - Orion South
DS201412-0344
2013
Read, G.Harvey, S., Read, G., DesGagnes, B., Shimell, M., van Breugel, B., Fourie, L.Utilization of olivine macrocryst grain size and abundance dat a as a proxy for diamond size and grade in pyroclastic deposits of the Orion South kimberlite, Fort a la Corne, Saskatchewan, Canada.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 79-96.Canada, SaskatchewanDeposit - Orion South
DS201412-0726
2014
Read, G.Read, G.The diamond industry supply + demand = price?SRK and Friends Diamond Short Course, March 1, ppt p. 1- 25GlobalEconomics
DS201501-0027
2015
Read, G.Read, G.Star-Orion South diamond project: optimizing a feasibility study.PDAC 2015, 1p. AbstractCanada, SaskatchewanDeposit - Star-Orion South
DS201712-2704
2017
Read, G.McCandless, T., desGagnes, B., Shimell, M., Read, G.Geology of the K6-252 kimberlite complex, Alberta.45th. Annual Yellowknife Geoscience Forum, p. 102 abstract posterCanada, Albertadeposit - K6-252
DS201910-2252
2019
Read, G.Czas, J., Pearson, D.G., Stachel, T., Kjarsgaard, B.A., Read, G.A diamondiferous paleoproterozoic mantle root beneath the Sask craton ( western Canada).Goldschmidt2019, 1p. AbstractCanada, Saskatchewancraton

Abstract: Primary diamond deposits are typically restricted to the stable Archean cores of continents, an association known as Clifford’s rule. Archean to Palaeoproterozoic crustal ages (3.3 - 2.1 Ga) have been reported for the Sask Craton, a small terrane in Western Canada, which hosts the diamondiferous Cretaceous Fort à la Corne (FALC) Kimberlite Field. Yet the craton is enclosed by the Palaeoproterozoic (1.9 - 1.8 Ga) Trans Hudson Orogen (THO). In this study we evaluate the age and geochemistry (major, trace, and platinum group elements data, as well as Re-Os isotope systematics) of the lithospheric mantle root beneath the Sask Craton to assess the timing of craton formation and the potential role played by the THO in its evolution. The lithospheric mantle root is dominated by lherzolite with average olivine Mg# of 91.5, which is more fertile than observed in other cratons. Garnets from concentrate further highlight the rarity of harzburgite in the lithospheric mantle. Single clinopyroxene thermobarometry provides temperaturepressure constraints for the garnet-bearing lithospheric mantle (840 to 1250 °C and 2.7 to 5.5 GPa), indicative of a cool geotherm (38 mW/m2) and a large diamond window of ~100 km thickness (from ~120-220 km depth). Most of the studied xenoliths show evidence for melt metasomatism in their trace and major element compositions, while retaining platinum group element patterns expected for melt residues. 187Os/188Os compositions span a broad range from 0.1109 to 0.1507, corresponding to Re-depletion (TRD) ages between 2.4 to 0.3 Ga, with a main mode in the Palaeoproterozoic (2.4 to 1.7 Ga). With the absence of Archean ages, the main depletion and stabilisation of the Sask Craton occurred in the Palaeoproterozoic, closely associated with the Wilson cycle of the THO. From a diamond exploration perspective this indicates that major diamond deposits can be found on cratons that were stabilised in the Palaeoproterozoic.
DS201912-2775
2019
Read, G.Czas, J., Pearson, G., Stachel, T., Kjarsgaard, B.A., Read, G.A Paleoproterozic diamond bearing lithospheric mantle root beneath the Archean Sask Craton.Lithos, 10.1016/j.lithos.2019.105301 63p. PdfCanada, Saskatchewancraton

Abstract: The recently recognised Sask Craton, a small terrane with Archean (3.3-2.5 Ga) crustal ages, is enclosed in the Paleoproterozoic (1.9-1.8 Ga) Trans Hudson Orogen (THO). Only limited research has been conducted on this craton, yet it hosts major diamond deposits within the Cretaceous (~106 to ~95 Ma) Fort à la Corne (FALC) Kimberlite Field. This study describes major, trace and platinum group element data, as well as osmium isotopic data from peridotitic mantle xenoliths (n = 26) from the Star and Orion South kimberlites. The garnet-bearing lithospheric mantle is dominated by moderately depleted lherzolite. Equilibration pressures and temperatures (2.7 to 5.5 GPa and 840 to 1250 °C) for these garnet peridotites define a cool geotherm indicative of a 210 km thick lithosphere, similar to other cratons worldwide. Many of the peridotite xenoliths show the major and trace element signatures of carbonatitic and kimberlitic melt metasomatism. The Re-Os isotopic data yield TRD (time of Re-depletion) model ages, which provide minimum estimates for the timing of melt depletion, ranging from 2.4 to 0.3 Ga, with a main mode spanning from 2.4 to 1.7 Ga. No Archean ages were recorded. This finding and the complex nature of events affecting this terrane from the Archean through the Palaeoproterozoic provide evidence that the majority of the lithospheric mantle was depleted and stabilised in the Palaeoproterozoic, significantly later than the Archean crust. The timing of the dominant lithosphere formation is linked to rifting (~2.2 Ga - 2.0 Ga), and subsequent collision (1.9-1.8 Ga) of the Superior and Hearne craton during the Wilson cycle of the Trans Hudson Orogen.
DS1995-0134
1995
Read, G.H.Bell, D.R., Schulze, D.J., Read, G.H., et al.Geochemistry of chromium poor megacrysts from the Lace (Group II) South Africa.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 52-54.South AfricaGeochemistry, Deposit -Crown (Lace)
DS1999-0587
1999
Read, G.H.Read, G.H.Victoria Island kimberlites - a case studyAssocation of Exploration Geologists (AEG) 19th. Diamond Exploration Methods Case Histories, pp. 66-70.Northwest Territories, Victoria IslandGeophysics, nickel thermometry, Geochemistry - indicators
DS2001-0797
2001
Read, G.H.Moore, R., Read, G.H.The Superior Craton: the diamond search intensifiesOntario Geological Survey, Northeastern Mineral Symposium, p.16-7, abstract.OntarioDiamond exploration - brief
DS2003-0033
2003
Read, G.H.Armstrong, K.A., Nowicki, T., Read, G.H.Kimberlite AT-56: a mantle sample from the north central Superior Craton, Canada8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractOntario, James Bay LowlandsDeposit - Attawapiskat
DS2003-0737
2003
Read, G.H.Kolebaba, M.R., Read, G.H., Kelsch, D., Kahlert, B.H.Diamondiferous kimberlites on Victoria Island, Canada: a northern extension of the8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractNorthwest Territories, Victoria IslandKimberlite geology and economics
DS2003-1143
2003
Read, G.H.Read, G.H., Grutter, H.S., Winter, L.D.S., Luckman, N.B., Gaunt, G.F.M.Stratigraphic relations, kimberlite emplacement and lithospheric thermal evolution8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, AbstractBrazil, Minas GeraisDiamond exploration - thermometry, pipe emplacement
DS200412-0052
2003
Read, G.H.Armstrong, K.A., Nowicki, T., Read, G.H.Kimberlite AT-56: a mantle sample from the north central Superior Craton, Canada.8 IKC Program, Session 8, POSTER abstractCanada, Ontario, Attawapiskat, James Bay LowlandsDiamond exploration Deposit - Attawapiskat
DS200412-0053
2004
Read, G.H.Armstrong, K.A., Nowicki, T.E., Read, G.H.Kimberlite AT-56: a mantle sample from the north central Superior Craton, Canada.Lithos, Vol. 77, 1-4, Sept. pp. 695-704.Canada, Ontario, Attawapiskat, James Bay LowlandsWebsteritic mantle, eclogite, Ni thermometry
DS200412-1641
2003
Read, G.H.Read, G.H., Grutter, H.S., Winter, L.D.S., Luckman, N.B., Gaunt, G.F.M.Stratigraphic relations, kimberlite emplacement and lithospheric thermal evolution, Quirico Basin, Minas Gerais State, Brazil.8 IKC Program, Session 8, AbstractSouth America, Brazil, Minas GeraisDiamond exploration - thermometry, pipe emplacement
DS200912-0616
2009
Read, G.H.Read, G.H.Diamond industry status and future prospects.PDAC 2009, 1p. abstractGlobalEconomics
DS200912-0617
2009
Read, G.H.Read, G.H., Janse, A.J.A.Diamonds: exploration, mines and marketing.Lithos, in press available, 8p.GlobalProduction, economics
DS201312-0182
2013
Read, G.H.Creighton, S., Read, G.H.Metasomatic overprinting of the lithospheric mantle of the Archean Saskatchewan Craton.GAC-MAC 2013 SS4: from birth to the mantle emplacement in kimberlite., abstract onlyCanada, SaskatchewanMetasomatism
DS202002-0172
2019
Read, G.H.Czas, J., Pearson, D.G., Stachel, T., Kjarsgaard, B.A., Read, G.H.A Paleoproterozoic diamond bearing lithospheric mantle root beneath the Archean Sask craton, Canada.Lithos, DOI:10.1016/ j.lithos.2019.105301Canada, Saskatchewandiamond genesis

Abstract: The recently recognised Sask Craton, a small terrane with Archean (3.3-2.5 Ga) crustal ages, is enclosed in the Paleoproterozoic (1.9-1.8 Ga) Trans Hudson Orogen (THO). Only limited research has been conducted on this craton, yet it hosts major diamond deposits within the Cretaceous (~106 to ~95 Ma) Fort à la Corne (FALC) Kimberlite Field. This study describes major, trace and platinum group element data, as well as osmium isotopic data from peridotitic mantle xenoliths (n = 26) from the Star and Orion South kimberlites. The garnet-bearing lithospheric mantle is dominated by moderately depleted lherzolite. Equilibration pressures and temperatures (2.7 to 5.5 GPa and 840 to 1250 °C) for these garnet peridotites define a cool geotherm indicative of a 210 km thick lithosphere, similar to other cratons worldwide. Many of the peridotite xenoliths show the major and trace element signatures of carbonatitic and kimberlitic melt metasomatism. The Re-Os isotopic data yield TRD (time of Re-depletion) model ages, which provide minimum estimates for the timing of melt depletion, ranging from 2.4 to 0.3 Ga, with a main mode spanning from 2.4 to 1.7 Ga. No Archean ages were recorded. This finding and the complex nature of events affecting this terrane from the Archean through the Palaeoproterozoic provide evidence that the majority of the lithospheric mantle was depleted and stabilised in the Palaeoproterozoic, significantly later than the Archean crust. The timing of the dominant lithosphere formation is linked to rifting (~2.2 Ga - 2.0 Ga), and subsequent collision (1.9-1.8 Ga) of the Superior and Hearne craton during the Wilson cycle of the Trans Hudson Orogen.
DS1983-0531
1983
Read, P.Read, P.Digging for Diamonds. #2Canadian Jeweller., Vol. 104, No. 5, PP. 28-32.South Africa, Kimberley AreaFinsch, History, Visit
DS1988-0564
1988
Read, P.Read, P.Dictionary of GemologyButterworth, Revised edition ( prev. 1982), 266p. Butterworth Scientific 25lbGlobalDictionary, Gemology
DS1992-1262
1992
Read, P.Read, P.Diamond mine... novel about diamond mining.. well reviewedBook Guild, Sussex England., 188p. approx. $ 25.00South AfricaNovel
DS1995-1554
1995
Read, P.Read, P.The Peking diamondsGems and Gemology, Vol. 32, Spring p. 68. $ 17.00ChinaBook review
DS1992-1263
1992
Read, P.B.Read, P.B., et al.Metamorphic map of the Canadian CordilleraGeological Survey of Canada, Map 1714A, 1: 2, 000, 000 $ 9.00British Columbia, CordilleraMap, Metamorphic
DS1975-0846
1978
Read, P.G.Read, P.G.Gemmological InstrumentsLondon: Narnes-butterworths, 227P.GlobalKimberlite, Kimberley, Janlib, Gemology
DS200612-1475
2006
Read, S.E.Veevers, J.J., Belousova, E.A., Saced, A., Sircombe, K., Cooper, A.F., Read, S.E.Pan-Gondwanaland detrital zircons from Australia analyzed for Hf isotopes and trace elements reflect an ice covered Antartic provenance 700-500 Ma alkalinityEarth Science Reviews, in press,AustraliaGeochronology, trace elements
DS200612-1476
2006
Read, S.E.Veevers, J.J., Belousova, E.A., Saeed, A., Sircombe, K., Cooper, A.F., Read, S.E.Pan Gondwanaland detrital zircons from Australia analysed for Hf isotopes and trace elements reflect an ice covered Antarctic provenance of 700-500 Ma ...Earth Science Reviews, Vol. 76, 3-4, June pp. 135-174.AustraliaGeochronology, alkaline affinity
DS1998-0833
1998
ReadingLarter, R.D., King, E.C., Leat, P.T., Reading, SmellieSouth Sandwich slices reveal much about arc structure, geodynamics andcomposition.Eos, Vol. 79, No. 24, June 16, p. 281, 284-5.GlobalGeodynamics - not specific to diamonds, Arc structure
DS2003-1144
2003
Reading, A.M.Reading, A.M., Kennett, B.L.N.Lithospheric structure of the Pilbara Craton, Capricorn Orogen and northern YilgarnAustralian Journal of Earth Sciences, Vol. 50, 3, June pp. 439-446.Australia, western AustraliaGeophysics - seismics, Craton - not specific to diamonds
DS2003-1145
2003
Reading, A.M.Reading, A.M., Kennett, B.L.N., Dentith, M.C.Seismic structure of the Yilgarn Craton, western AustraliaAustralian Journal of Earth Sciences, Vol. 50, 3, June pp. 427-38.Australia, western AustraliaGeophysics - seismics, Craton - not specific to diamonds
DS200412-1642
2003
Reading, A.M.Reading, A.M., Kennett, B.L.N.Lithospheric structure of the Pilbara Craton, Capricorn Orogen and northern Yilgarn Craton, western Australia, from teleseismicAustralian Journal of Earth Sciences, Vol. 50, 3, June pp. 439-446.Australia, Western AustraliaGeophysics - seismics Craton - not specific to diamonds
DS200412-1643
2003
Reading, A.M.Reading, A.M., Kennett, B.L.N., Dentith, M.C.Seismic structure of the Yilgarn Craton, western Australia.Australian Journal of Earth Sciences, Vol. 50, 3, June pp. 427-38.Australia, Western AustraliaGeophysics - seismics Craton - not specific to diamonds
DS200512-0291
2005
Reading, A.M.Fishwick, S., Kennett, B.L.N., Reading, A.M.Contrasts in lithospheric structure within the Australian Craton - insights from surface wave tomography.Earth and Planetary Science Letters, Vol. 231, 3-4, March 15, pp. 163-176.AustraliaGeophysics - seismics, tomography, Proterozoic
DS200512-0510
2004
Reading, A.M.Kennett, B.L.N., Fishwick, S., Reading, A.M., Rawlinson, N.Contrasts in mantle structure beneath Australia: relation to Tasman Lines?Australian Journal of Earth Sciences, Vol. 51, 4, August pp. 563-370.AustraliaTectonics
DS200712-0879
2006
Reading, A.M.Reading, A.M.Precambrian terranes in West Australia and East Antarctica: seismic structure and implications for continent formation and evolution.Geochimica et Cosmochimica Acta, In press availableAustralia, AntarcticaGeophysics - seismics
DS200812-0354
2008
Reading, A.M.Fishwick, S., Heintz, M., Kennett, B.L.N., Reading, A.M., Yoshizawa, K.Steps in lithospheric thickness within eastern Australia, evidence from surface wave tomography.Tectonics, Vol. 27, TC 4009AustraliaTomography
DS1986-0858
1986
Reading, H.G.Watson, J.V., Reading, H.G.Major crustal lineaments and their influence on the geological history Of the continental lithosphere.Phil. Transactions Royal Society of London, Vol. A317, pp. 1-290.West Africa, central AfricaTectonics, rifting, lineaments, shear zones, volcanism.
DS1998-1099
1998
Readman, P.W.O'Reilly, B.M., Readman, P.W., Hauser, F.Lithospheric structure across the western Eurasian obate from a wide angle seismic and gravity study...Earth and Planetary Science Letters, Vol. 156, pp. 275-280.GlobalGeothermometry - regional, basin, Geophysics - seismics
DS1998-1100
1998
Readman, P.W.O'Reilly, B.M., Readman, P.W., Hauser, F.Lithospheric structure across the western Eurasian Plate from a wide angle seismic and gravity study...Earth and Planetary Science Letters, Vol. 156, No. 3-4, pp. 275-280.GlobalGeothermometry, Tectonics
DS201811-2603
2018
Ready, R.A.Ravi, S., Bhaskara Rao, K.S., Ready, R.A.Diamond Fields of southern India. Review in researchgateGeological Survey of India Bulletin Series A, No. 68, 996p. Indiahistory, diamond occurrence
DS1920-0347
1927
Reagan, A.B.Reagan, A.B.Garnets in the Navajo CountryAmerican MINERALOGIST., Vol. 12, P. 414.United States, Rocky Mountains, New Mexico, Colorado PlateauMineralogy
DS1994-1239
1994
Reagan, M.Morris, J., Reagan, M.Timescales for slab mantle interactions leading to volcanism at convergentmargins.Geological Society of America (GSA) Abstract Volume, Vol. 26, No. 7, ABSTRACT only p. A30.MantleSubduction
DS201412-0936
2014
Reagan, M.Turner, S., Rushmer, T., Reagan, M., Moyen, J-F.Heading down early on? Start of subduction on Earth.Geology, Vol. 42, 2, pp. 139-142.MantleSubduction
DS1981-0345
1981
Reagor, B.G.Reagor, B.G., et al.Seismicity Map of the State of South DakotaUnited States Geological Survey (USGS) MAP, No. MF-1325, 1: 1, 000, 000.GlobalMid-continent, Geophysics
DS1981-0399
1981
Reagor, B.G.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
DS1987-0715
1987
Reagor, B.G.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
Reagor, B.G.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
Reagor, B.G.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
Reagor, B.G.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
Reagor, B.G.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
DS1950-0424
1958
Real, F.Real, F.Sur les Roches Kimberlitiques de la Lunda (angola)University LISBOA FAC. SCI. Bulletin., No. 26AngolaKimberlite, Geology, Petrology
DS1950-0497
1959
Real, F.Real, F.Intrusoes Kimberliticas Da LundaLisbon: Dir. Ger. Minas E Serv. Geol. Memoir., No. 5, 116P. XEROX.AngolaKimberlite, Kimberley, Janlib
DS201912-2804
2019
Reali, A.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%.
DS201902-0304
2019
Reali, R.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.
DS201904-0771
2019
Reali, R.Reali, R., Jackson, J.M., Van Orman, J., Bower, D.J., Carrez, P., Cordier, P.Modeling viscosity of ( Mg, Fe)O at lowermost mantle conditions.Physics of the Earth and Planetary Interiors, Vol. 287, pp. 65-75.Mantlecore-mantle boundary

Abstract: The viscosity of the lower mantle results from the rheological behavior of its two main constituent minerals, aluminous (Mg,Fe)SiO3 bridgmanite and (Mg,Fe)O ferropericlase. Understanding the transport properties of lower mantle aggregates is of primary importance in geophysics and it is a challenging task, due to the extreme time-varying conditions to which such aggregates are subjected. In particular, viscosity is a crucial transport property that can vary over several orders of magnitude. It thus has a first-order control on the structure and dynamics of the mantle. Here we focus on the creep behavior of (Mg,Fe)O at the bottom of the lower mantle, where the presence of thermo-chemical anomalies such as ultralow-velocity zones (ULVZ) may significantly alter the viscosity contrast characterizing this region. Two different iron concentrations of (Mg1-xFex)O are considered: one mirroring the average composition of ferropericlase throughout most of the lower mantle (x?=?0.20) and another representing a candidate magnesiowüstite component of ULVZs near the base of the mantle (x?=?0.84). The investigated pressure-temperature conditions span from 120?GPa and 2800?K, corresponding to the average geotherm at this depth, to core-mantle boundary conditions of 135?GPa and 3800?K. In this study, dislocation creep of (Mg,Fe)O is investigated by dislocation dynamics (DD) simulations, a modeling tool which considers the collective motion and interactions of dislocations. To model their behavior, a 2.5 dimensional dislocation dynamics approach is employed. Within this method, both glide and climb mechanisms can be taken into account, and the interplay of these features results in a steady-state condition. This allows the retrieval of the creep strain rates at different temperatures, pressures, applied stresses and iron concentrations across the (Mg,Fe)O solid solution, providing information on the viscosity for these materials. A particularly low viscosity is obtained for magnesiowüstite with respect to ferropericlase, the difference being around 10 orders of magnitude. Thus, the final section of this work is devoted to the assessment of the dynamic implications of such a weak phase within ULVZs, in terms of the viscosity contrast with respect to the surrounding lowermost mantle.
DS201504-0212
2015
Reaman, D.M.Panero, W.R., Pigott, J.S., Reaman, D.M., Kabbes, J.E., Liu, Z.Dry ( Mg,Fe) SiO3 perovskite in the Earth's lower mantle.Journal of Geophysical Research, Vol. 120, 2, pp. 894-908.MantlePerovskite
DS200712-0880
2007
Reaney, B.Reaney, B.Fair trade diamonds... question remains whether or not they've been a net benefit to northern aboriginals.Canadian Diamonds, Spring, pp. 33,34,36,38,48.CanadaAboriginal
DS200612-1144
2006
Reany, B.Reany, B.Cutting .. a fine edge.. Federal loans and diamond cutting industry.Canadian Diamonds, Spring pp.20-24, 48Canada, Northwest TerritoriesDiamond cutting and polishing factories
DS1975-1066
1979
Reavis, G.L.Hausel, W.D., Reavis, G.L.Review of Diamond Prospecting in Northern Colorado and Southern Wyoming.Northwest Mining Association 85th. Annual Meeting, ABSTRACT.United States, Colorado, Wyoming, State Line, Rocky MountainsBlank
DS1975-1067
1979
Reavis, G.L.Hausel, W.D., Reavis, G.L., Stephenson, T.R.Prospecting for Kimberlite in Wyoming Using Heavy Mineral Alluvial sampling Methods.Wyoming Geological Survey Open File Report, No. 79-6, 13P.United States, Wyoming, State Line, Rocky MountainsBlank
DS1960-0591
1965
Reay, A.Reay, A.Mantle Composition and Partial Fusion of Possible Mantle Material.Ph.d. Thesis, University of Leeds, GlobalMantle Genesis, Experimental Petrology
DS201012-0081
2009
RebakBurns, R.C., Chumakov, A.I., Connell, Dube, Godfried, Hansen, Hartwig, Hoszowska, Masiello, Mkonza, RebakHPHT growth and x-ray characterization of the high quality type IIa diamond.Journal of Physics Condensed Matter, Vol. 21, 36, pp. 364224-364237.TechnologyType II a
DS2002-1318
2002
Rebay, G.Rebay, G., Powell, R.The formation of eclogite facies metatroctolites and a general petrogenetic grid in Na2O CaO FeO MgO AL2O3 SiO2 H2O ( NCFMASH).Journal of Metamorphic Geology, Vol. 20, 9, pp. 813-26.GlobalEclogites, Petrology
DS201012-0615
2010
Rebay, G.Rebay, G., Powell, R., Diener, J.F.A.Calculated phase equilibration temperatures for a morb compositoon in a P-T range, 450-650 C and 18-28 kbar: the stability of eclogite.Journal of Metamorphic Geology, Vol. 28, 6, pp. 635-645.MantleEclogite
DS1996-0405
1996
Rebbeck, R.J.Eberle, D., Hutchins, D.G., Rebbeck, R.J., Somerton, I.Compilation of the Namibian airborne magnetic surveys: procedures, problem sand results.Journal of African Earth Sciences, Vol. 22, No. 2, Feb. pp. 191-206.NamibiaGeophysics -magnetics, Compilation
DS202010-1871
2020
Rebeiro, B.V.Rebeiro, B.V., Cawood, P.A., Faleiros, F.M., Mulder, J.A., Martin, E., Finch, M.A., Raveggi, M., Teixeira, W., Cordani, U.G., Pavan, M.A long lived active margin revealed by zircon U-Pb-Hf data from the Rio Apa terrane (Brazil): new insights into the Paleoproterozoic evolution of the Amazonian craton.Precambrian Research, 57p. PdfSouth America, Brazilcraton

Abstract: We present the first regional in-situ zircon U-Pb-Hf isotopic data from metaigneous and metasedimentary rocks from the Paleo- to Mesoproterozoic Rio Apa Terrane (RAT), a crustal fragment outcropping in the central-western Brazil and north-eastern Paraguay. These new ages and Hf isotopic data delineate three magmatic events, which record the construction of the temporally and isotopically distinct Western and Eastern Terranes of the RAT. The Western Terrane comprises the 2100-1940 Ma Porto Murtinho Complex and the 1900-1840 Ma Amoguijá Belt, which both define a crustal reworking array in ?HfT-time space evolving from a precursor source with Hf TDM age of ca. 2700 Ma. The 1800-1720 Ma Caracol Belt constitutes the Eastern Terrane and yields suprachondritic ?HfT signatures up to +7.1, indicating significant juvenile input. The metasedimentary Amolar Group and Rio Naitaca Formation in the Western Terrane have maximum depositional ages of 1850-1800 Ma and subchondritic ?HfT signatures down to ?5.7, similar to the underlying basement of the Amoguijá Belt. In the Eastern Terrane, the Alto Tererê Formation has a maximum depositional age of 1750 Ma and mostly suprachondritic ?HfT signatures, similar to magmatic rocks of the underlying Caracol Belt. Together, the new igneous and detrital zircon age and Hf isotopic data record a temporal and spatial transition from 2100 to 1840 Ma crustal reworking in the west to more juvenile magmatism at 1800-1720 Ma in the east. This transition is interpreted to reflect convergent margin magmatism associated with periods of subduction zone advance and retreat in an accretionary orogenic setting. Comparison of the ?HfT-time signature of the RAT with the Amazonian Craton suggest penecontemporaneous development, with the Western and Eastern Terranes of the RAT being correlative with the Ventuari-Tapajós and Rio Negro-Juruena Province of the Amazonian Craton, respectively. Our new data also reveal that the ?HfT signatures of the RAT are distinct from the Maz terrane, which refutes the MARA Block hypothesis.
DS201710-2260
2017
Rebetsky, Yu.L.Rebetsky, Yu.L., Sim, L.A., Kozyrev, A.A.Possible mechanism of horizontal overpressure generation of the Khibiny, Lovozero, and Kovdor ore clusters on the Kola Peninsula.Geology of Ore Deposits, Vol. 59, 4, pp. 265-280.Russia, Kola Peninsuladeposit - Khibiny, Lovozero, Kovdor

Abstract: The paper discusses questions related to the generation of increasing crustal horizontal compressive stresses compared to the idea of the standard gravitational state at the elastic stage or even from the prevalence of horizontal compression over vertical stress equal to the lithostatic pressure. We consider a variant of superfluous horizontal compression related to internal lithospheric processes occurrin in the crust of orogens, shields, and plates. The vertical ascending movements caused by these motions at the sole of the crust or the lithosphere pertain to these and the concomitant exogenic processes giving rise to denudation and, in particular, to erosion of the surfaces of forming rises. The residual stresses of the gravitational stressed state at the upper crust of the Kola Peninsula have been estimated for the first time. These calculations are based on the volume of sediments that have been deposited in Arctic seas beginning from the Mesozoic. The data speak to the possible level of residual horizontal compressive stresses up to 90 MPa in near-surface crustal units. This estimate is consistent with the results of in situ measurements that have been carried out at the Mining Institute of the Kola Science Center, Russian Academy of Sciences (RAS), for over 40 years. It is possible to forecast the horizontal stress gradient based on depth using our concept on the genesis of horizontal overpressure, and this forecasting is important for studying the formation of endogenic deposits.
DS1984-0604
1984
Recker, K.Recker, K.Synthetische DiamantentZeitschrift Der Deutschen Gemmologischen Gesellschaft., Vol. 33, No. 1-2, PP. 5-34.GlobalSynthetic
DS1985-0556
1985
Recker, K.Recker, K.Synthetische DiamantenZeitschrift Der Deutschen Gemmologischen Gesellschaft., Vol. 33, No. 1/2. PP. 5-34.GlobalReview
DS1983-0532
1983
Reckling, K.Reckling, K., Hoy, R.B., Lefond, S.J.Diamonds; Industrial Minerals and Rocks, 1983Industrial Minerals And Rocks, Fifth Edition, New York: A.i., PP. 653-676.GlobalReview, History, Production, Mineral Economics, Mining Engineering
DS1860-1098
1899
Reclus, E.Reclus, E.Universal GeographyUnknown., Vol. 13, PP. 149-155.Africa, South Africa, East AfricaGeography
DS1987-0604
1987
Records of the Geological Survey IndiaRecords 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
DS1989-0137
1989
Recq, M.Boillot, G., Feraud, G., Recq, M., Girardeau, J.Undercrusting by serpentinite beneath rifted marginsNature, Vol. 341, October 12, pp. 523-525. Database # 18207SpainTectonics, Mantle
DS1996-0433
1996
Reczko, B.F.F.Eriksson, P.G., Reczko, B.F.F., Jenkins, S.L.The Kanye axis, Kaapvaal Craton, a postulated Archean crustal architectural element - 3D basin modeling..Journal of African Earth Science, Vol. 22, No. 3, April 1, pp. 223-234South AfricaGeophysics -structure basin, Craton -Kaapvaal
DS1997-0319
1997
Reczko, B.F.F.Eriksson, P.G., Reczko, B.F.F.The late Archean to Mesoproterozoic major unconformity bounded units of the Kaapvaal Province Southern AfricaPrecambrian Research, Vol. 81, No. 1-2, Jan. 1, pp. 145-149South AfricaKaapvaal Province, Stratigraphy
DS201904-0715
2019
Redaa, A.Armistead, S.E., Collins, A.S., Redaa, A., Gilbert, S., Jepson, G., Gillespie, J., Blades, M.L., Foden, J.D., Razakamana, T.Structural evolution and medium temperature thermochronology of central Madagascar: implications for Gondwana amalgamation.Journal of the Geological Society of London, in press available 25p.Africa, Madagascarthermochronology

Abstract: Madagascar occupied an important place in the amalgamation of Gondwana, and preserves a record of several Neoproterozoic events that can be linked to orogenesis of the East African Orogen. We integrate remote sensing and field data to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic foliation (S1), followed by south to south-west directed, tight to isoclinal, recumbent folding (D2). These are overprinted by north-trending upright folds that formed during a ~E-W shortening event. Together these produced type 1 and type 2 fold interference patterns throughout the Itremo and Ikalamavony domains. Apatite U-Pb and muscovite and biotite Rb-Sr thermochronometers indicate that much of central Madagascar was thermally reset to at least ~500oC at c. 500 Ma. Deformation in west-central Madagascar occurred between c. 750 Ma and c. 550 Ma, and we suggest this deformation formed in response to the c. 650 Ma collision of Azania with Africa along the Vohibory Suture in southwestern Madagascar. In eastern Madagascar, deformation is syn- to post-550 Ma, which formed in response to the final closure of the Mozambique Ocean along the Betsimisaraka Suture that amalgamated Madagascar with the Dharwar Craton of India.
DS202010-1826
2020
Redaa, A.Armistead, S.E., Collins, A.S., Redaa, A., Jepson, G., Gillespie, J., Gilbert, S., Blades, M.L., Foden, J.D., RazakMnN, T.Structural evolution and medium temperature thermochronology of central Madagascar: implications for Gondwana amalagamation.Journal of the Geological Society, Vol. 177, pp. 784-798.Africa, Madagascargeothermometry

Abstract: Madagascar occupied an important place in the amalgamation of Gondwana and preserves a record of several Neoproterozoic events that are linked to orogenesis of the East African Orogen. In this study, we integrate remote sensing, field data and thermochronology to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic foliation (S1), followed by south- to SW-directed, tight to isoclinal, recumbent folding (D2). These are overprinted by north-trending upright folds that formed during an approximately east-west shortening event (D3). Together these produced type 1 and type 2 fold interference patterns throughout the Itremo and Ikalamavony domains. We show that the Itremo and Ikalamavony domains were deformed together in the same orogenic system, which we interpret as the c. 630 Ma collision of Azania with Africa along the Vohibory Suture in southwestern Madagascar. In eastern Madagascar, deformation is syn- to post-550 Ma, and probably formed in response to final closure of the Mozambique Ocean along the Betsimisaraka Suture that amalgamated Madagascar with the Dharwar Craton of India. Apatite U-Pb and novel laser ablation triple quadrupole inductively coupled plasma mass spectrometry (LA-QQQ-ICP-MS) muscovite and biotite Rb-Sr thermochronology indicates that much of central Madagascar cooled through c. 500°C at c. 500 Ma.
DS1980-0286
1980
Redcliffe, T.Redcliffe, T., Cra exploration pty. ltd.Tr 7386h to Tr 7309h Rosewood ...diamond Exploration Lissadell Sheet.West Australia Geological Survey Open File., No. GSWA 1196 ROLE 403 M 2644/1. 25P.Australia, Western AustraliaProspecting, Stream Sediment Sampling
DS1995-1078
1995
Redcliffe, T.H.Lee, D.C., Milledge, H.J., Redcliffe, T.H., Scott SmithThe Merlin kimberlites, Northern Territory, AustraliaProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 317-319.AustraliaPetrography, Deposit -Merlin, Bedevere, Palomides, Launfal, Excalibur
DS1992-1264
1992
Redclift, M.Redclift, M.The meaning of sustainable developmentGeoforuM., Ol. 23, No. 3, pp. 395-403GlobalEconomics, World, Environment, mining
DS1991-0972
1991
Reddicliffe, T.Lee, D.C., Boyd, F.R., Griffin, B.J., Reddicliffe, T.Coanjula diamonds, northern Territory, AustraliaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 231-233AustraliaMicrodiamonds, Microscopy, diamond morphology
DS1994-1014
1994
Reddicliffe, T.Lee, D.C., Boyd, S.R., Griffin, B.J., Griffin, B.W, Reddicliffe, T.Coanjuta diamonds, Northern Territory, AustraliaProceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 51-68.AustraliaDiamond morphology, Deposit -Coanjuta
DS1995-1555
1995
Reddicliffe, T.Reddicliffe, T., Taylor, W., Ong, N., Tompkins, L.A.The igneous rocks from the Coanjula microdiamond deposit, NorthernTerritory, Australia.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 460-461.AustraliaMicrodiamonds, Deposit -Coanjula
DS1998-0848
1998
Reddicliffe, T.Lee, D., Reddicliffe, T., Scott Smith, B., Taylor, WardMerlin Diamondiferous kimberlite pipesBerkman, Mackenzie, Geol. Australia Papua New Guinea, AusIMM Mon. 22, pp. 461-466.AustraliaGeology, Deposit - Merlin
DS202008-1455
2020
Reddicliffe, T.Vasilyev, P., McInnes, B., Reddicliffe, T.Evaluation of the source of diamonds and other kimberlitic minerals from the Webb kimberlite field, western Australia.Goldschmidt 2020, 1p. AbstractAustralia, Western Australiadeposit - Webb

Abstract: play located ~600 km west of Alice Springs in a remote region of WA. Exploration by GeoCrystal Ltd has identified more than 280 ‘bulls-eye’ magnetic features over a ~400 km2 area. Reconnaissance drilling of some of these features has returned mineral samples of kimberlite affinity, while surface sampling has recovered detrital microdiamonds with the number of inclusions, later analysed with FIBSEM. The unaltered diamond indicator minerals from drill samples analysed include: (i) G9 garnet predominating over G10; (ii) olivine ranging from Fo84-Fo91; (iii) Crdiopside (0.8-1.8% Cr2O3) and (iv) a broad range of Cr-Al spinel. A thermobarometric assessments of mineral chemistry data [1-3] show good agreement with each other and indicate a mantle origin for number of northern targets, including ones at possible equilibrium within the diamond stability field (P=45-50 kbar; T=1150- 1170°C). These results contain important information about the understudied deep lithosphere of Central Australia region.
DS1998-1454
1998
Reddicliffe, T.H.Taylor, W.R., Reddicliffe, T.H., Jakimowicz, J.Thermobarometry of peridotitic chromium diopside from the Merlin kimberlites -nature of upper mantle..7th International Kimberlite Conference Abstract, pp. 899-901.AustraliaProterozoic, craton, Deposit - Merlin
DS2003-1146
2003
Reddicliffe, T.H.Reddicliffe, T.H., Jakimowicz, J., Hell, A.J., Robins, J.A.The geology, mineralogy and near surface chacteristics of the Ashmore and Seppelt8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractAustraliaKimberlite geology and economics, Deposit - Ashmore, Seppelt
DS201804-0730
2017
Reddicliffe, T.H.Reddicliffe, T.H., Kammermann, M.S.Merlin diamond deposit.Australian Ore Deposits, AusIMM Monograph 32, ed. Phillips, N., pp. 533-534.Australiadeposit - Merlin
DS2002-1319
2002
ReddyReddy, B.J., Yamauchi, J., Reddy, Ravikumar, ChandraseskharOptical and EPR spectra of Ti 3 in lamprophyllite from Kola Peninsula, RussiaNeues Jahrbuch fur Mineralogie - Monatshefte, No.3, March,ppp.138-40.Russia, Kola PeninsulaMineralogy - titanium
DS200712-0866
2007
ReddyRajendra Prasad, B., Kesava Rao, G., Mall, D.M., Koteswarar Rao, P., Raju, S., Reddy, SridherTectonic implications of seismic reflectivity pattern observed over the Precambrian southern granulite terrain, India.Precambrian Research, Vol. 153, 1-2, pp. 1-10.IndiaGeophysics - seismics
DS200712-1028
2007
Reddy, A.G.S.Srinivas, M., Reddy, A.G.S.The Podili alkaline complex, Prakasam alkaline province, Andhra Pradesh, southern India.Plates, Plumes, and Paradigms, 1p. abstract p. A963.India, Andhra PradeshAlkalic
DS1986-0595
1986
Reddy, A.K.Nehru, C.E., Reddy, A.K.Ultramafic xenoliths from Vajrakarur kimberlites, India #1Proceedings of the Fourth International Kimberlite Conference, Held, No. 16, pp. 81-83IndiaPetrology
DS1986-0663
1986
Reddy, A.K.Reddy, A.K.Petrology and geochemistry of Vajrakarur kimberlitesRecords of the Geological Survey of India, Vol. 115, pt. 5, No. 5, pp. 54-66IndiaPetrology, Andhra Pradesh, Lattavara
DS1987-0605
1987
Reddy, A.K.Reddy, A.K.Kimberlite and lamproite rocks of Vajrakarur area, Andhra PradeshGeological Society India Journal, Vol. 30, No. 1, July, pp. 1-IndiaKimberlite, Lamproite
DS1989-1102
1989
Reddy, A.K.Nehru, C.E., Reddy, A.K.Ultramafic xenoliths from Vajrakarur kimberlites, India #2Geological Society of Australia Inc. Blackwell Scientific Publishing, No. 14, Vol. 2, pp. 745-58IndiaGeothermobarometry, Xenoliths
DS2002-1319
2002
Reddy, B.J.Reddy, B.J., Yamauchi, J., Reddy, Ravikumar, ChandraseskharOptical and EPR spectra of Ti 3 in lamprophyllite from Kola Peninsula, RussiaNeues Jahrbuch fur Mineralogie - Monatshefte, No.3, March,ppp.138-40.Russia, Kola PeninsulaMineralogy - titanium
DS1991-0002
1991
Reddy, B.R.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
Reddy, B.R.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
DS1960-0873
1967
Reddy, B.S.R.Reddy, B.S.R., Ballal, N.R.R.Investigation for Ultrabasic Pipes and Other Basic Rocks In anantapur District, A.p.India Geological Survey Program Report, FOR 1966-1967India, Andhra PradeshBlank
DS1987-0606
1987
Reddy, C.V.Reddy, C.V.Interpretation of aeromagnetic dat a of eastern Cuddapah BasinIntegrated Geophysical Exploration for Mineral Deposits, Baroda India, Held, Vol. 13, p. A30. (Abstract)IndiaGeophysics, Kimberlite
DS2003-1138
2003
Reddy, G.K.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granite province: evidence from southern IndiaJournal of Geophysical Research, Vol. 108, B2, 10.1029/2001JB000688IndiaUHP
DS2003-1139
2003
Reddy, G.K.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., RaoHigh mantle heat flow in a Precambrian granulite province: evidence from southernJournal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP, Geothermometry
DS200412-1068
2004
Reddy, G.K.Kumar, P.S., Reddy, G.K.Radio elements and heat production of an exposed Archean crustal cross section, Dharwar craton, South India.Earth and Planetary Science Letters, Vol. 224, 3-4, pp. 309-324.IndiaGeothermometry, heat flow
DS200412-1637
2003
Reddy, G.K.Ray, L., Kumar, P.S., Reddy, G.K., Roy, S., Rao, G.V., Srinivasan, R., Rao, R.U.M.High mantle heat flow in a Precambrian granulite province: evidence from southern India.Journal of Geophysical Research, Vol. 108, 2, ETG 6IndiaUHP Geothermometry
DS200512-0681
2005
Reddy, G.L.Manikyamba, C., Naqvi, S.M., Subba Rao, D.V., Ram Mohan, M., Khanna, T.C., Rao, T.G., Reddy, G.L.Boninites from the Neoarchean Gadwal greenstone belt, eastern Dharwar Craton, India, implications for Archean subduction processes.Earth and Planetary Science Letters, Vol. 230, 1-2, pp. 65-83.IndiaBoninites
DS2003-0005
2003
Reddy, K.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
Reddy, K.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
DS2003-1147
2003
Reddy, K.S.Reddy, K.S., Raju, A.N.The physical and textural characteristics of termite mounds from Podili and TalupulaJournal of the Geological Society of India, Vol. 61, 6, June, pp. 693-98.IndiaBlank
DS200412-1644
2003
Reddy, K.S.Reddy, K.S., Raju, A.N.The physical and textural characteristics of termite mounds from Podili and Talupula areas, Andhra Pradesh.Journal of the Geological Society of India, Vol. 61, 6, June, pp. 693-98.IndiaGeomorphology - not specific to diamonds
DS201712-2721
2017
Reddy, K.V.S.Reddy, K.V.S.Precambrian lithostratigraphy of Dharwar craton and adjoining fold and mobile belts.Journal of the Geological Society of India, Vol. 90, 4, pp. 507-Indiacraton
DS1991-1404
1991
Reddy, L.K.T.Reddy, L.K.T.Digital analysis of lineaments- a test study on south IndiaComputers and Geosciences, Vol. 17, No. 4, pp. 549-560IndiaTectonics, Lineaments
DS200612-0969
2005
Reddy, N.S.Nayak, S.S., Ravi, S., Reddy, N.S., Rau, T.K.Petrology and geochemistry of the kimberlites of Dharwar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 58-59.India, Andhra Pradesh, Dharwar CratonPetrology
DS200612-0970
2005
Reddy, N.S.Nayak, S.S., Ravi, S., Sridhar, M., Reddy, N.S., Chowdary, V.S., Bhaskara Rao, K.S., Sinha, K.K., Rao, T.K.Geology and tectonic setting of kimberlites of Dharwar Craton.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 36-38.India, Andhra Pradesh, Dharwar CratonTectonics
DS200612-1134
2005
Reddy, N.S.Rau, T.K., Ravi, S., Chowdary, V.S., Bhaskara Rao, K.S., Reddy, N.S.Diamond prospects in Andhra Pradesh - a review.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 29-33.India, Andhra Pradesh, Dharwar CratonBrief overview
DS200612-1135
2005
Reddy, N.S.Rau, T.K., Reddy, N.S., Ravi, S., Sridhar, M., Chowdary, V.S., Bhaskara Rao, K.S.Primary source rocks for diamonds in Banaganapalle conglomerate ( Kurnool Group) - a critical appraisal.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 77-79.India, Andhra Pradesh, Dharwar CratonConglomerate - Banaganapalle
DS200612-1136
2005
Reddy, N.S.Ravi, S., Rau, T.K., Reddy, N.S., Nayak, S.S.Discovery of a new kimberlite field - the Tungaghadra kimberlite field, Kurnool District, Andhra Pradesh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 42-44.India, Andhra Pradesh, Dharwar CratonKimberlite - Tungaghadra
DS1998-1183
1998
Reddy, P.R.Prasad, B.R., Tewari, H.C., Reddy, P.R.Structure and tectonics of the Proterozoic Aravalli Delhi fold belt in northwest India from a deep seismic ....Tectonophysics, Vol. 288, No. 1-4, Mar. pp. 31-42.IndiaTectonics, Geophysics - seismic
DS2000-0806
2000
Reddy, P.R.Reddy, P.R.Seismic imaging of the crustal structure across the central Indian sutureGeological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-175.IndiaGeophysics - seismics, Craton
DS200512-0074
2004
Reddy, P.R.Behera, L., Sain, K., Reddy, P.R.Evidence of underplating from seismic and gravity studies in the Mahanadi delta of eastern India and its tectonic significance.Journal of Geophysical Research, Vol. 109, 12, DOI 10.1029/2003 JB002764IndiaTectonics
DS200712-0871
2006
Reddy, P.R.Rao, Viljaya, V., Sain, K., Reddy, P.R., Mooney, W.D.Crustal structure and tectonics of the northern part of the southern Granulite Terrane, India.Earth and Planetary Science Letters, Vol. 251, 1-2, Nov. 15, pp.90-103.IndiaTectonics - not specific to diamonds
DS200812-0706
2008
Reddy, P.R.Mali, B.M., Pendey, G.P., Candrakala, K., Reddy, P.R.Imprints of a Proterozoic tectonothermal anomaly below the 1.1 Ga kimberlitic province of southwest Cuddapah Basin, Dharwar craton, southern India.Geophysical Journal International, Vol. 172, 1, pp. 422-438.IndiaGeothermometry
DS200812-0707
2008
Reddy, P.R.Mall, D.M., Pandey, O.P., Chandrakala, K., Reddy, P.R.Imprints of a Proterozoic tectonothermal anomaly below the 1.1 Ga kimberltic province of southwest Cuddapah basin, Dharwar craton ( Southern India).Geophysical Journal International, Vol. 172, 1, pp. 422-438.IndiaGeothermometry
DS200912-0471
2009
Reddy, P.R.Mall, D.M., Pandev, O.P., Chandrakala, K., Reddy, P.R.Imprints of a Proterozoic tectonothermal anomaly below the 1.1 Ga kimberlitic province of southwest Cuddapah basin, Dharwar Craton, southern India.Geophysical Journal International, Vol. 172, 1, pp. 422-438.IndiaGeothermometry
DS201312-0737
2012
Reddy, P.R.Reddy, P.R., Vijaya Rao, V.Seismic images of the continental Moho of the Indian shield.Tectonophysics, Vol. 609, pp. 217-233.IndiaGeophysics - seismics
DS201901-0060
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.History of diamond mining in India. GolcondaGeological Survey of India Bulletin A series No. 68, Chapter II pp. 3-25.India, southern Indiahistory

Abstract: Geological Survey of India Bulletin A series No. 68 is available as an open 1,033 page 32 MB pdf.
DS201901-0061
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Diamond deposits and their host rocks. Indian kimberlites and lamproites.Geological Survey of India Bulletin A series No. 68, Chapter III pp. 26-39.India, southern Indiapetrology
DS201901-0062
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Status of diamond - kimberlite-lamproite occurrences in India. Fields Wajrakarur field.Geological Survey of India Bulletin A series No. 68, Chapter IV pp. 40-653.India, southern Indiadeposit - Wajrakarur
DS201901-0063
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Exploration for diamonds in Banaganapalli conglomerates.Geological Survey of India Bulletin A series No. 68, Chapter V pp. 654-748.India, southern Indiadeposit - Banaganapalli
DS201901-0064
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Alluvial diamond deposits. Krishna, Pennar, SagileruGeological Survey of India Bulletin A series No. 68, Chapter VI pp. 749-830.India, southern Indiaalluvials
DS201901-0065
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Mantle xenoliths and xenocrysts.Geological Survey of India Bulletin A series No. 68, Chapter VII pp. 831-850.India, southern Indiametasomatism
DS201901-0066
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Diamonds from SIDP: their physical and infrared characteristics. FTIR ( De Beers studies)Geological Survey of India Bulletin A series No. 68, Chapter VIII pp. 851-910.India, southern Indiadiamond inclusions
DS201901-0067
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.Diamond exploration scenario in India: status and future perspectives. Geological Survey of India Bulletin A series No. 68, Chapter IX pp. 911-949.India, southern Indiadiamond exploration
DS201901-0068
2018
Reddy, R. A.Ravi, S., Bhaskara Rao, K.S., Reddy, R. A.References.Geological Survey of India Bulletin A series No. 68, Chapter X pp. 950-973.India, southern Indiareferences
DS200612-1145
2001
Reddy, R.A.Reddy, R.A., Murty, N.S., De, S.K.Target areas for kimberlite exploration from potential field dat a using geographic information system, Narayanpet kimberlite field, Andhra Pradesh.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 417-425.India, Andhra PradeshDiamond exploration - geophysics
DS202008-1433
2020
Reddy, R.A.Phani, P.R.C., Lira, R., Espeche, M.J., Reddy, R.A.Geochemical and petrological studies of a magmatic carbonate-bearing metalamprophyre ( spessartite) at Kalagalla - evidence for shoshonitic calc-alkaline magmatism within auriferous Ramagiri-Penakacherla schist belt ( 2.5Ga), eastern Dharwar craton, southGeochimica Brasiensis, Vol. 34, 1, pp. 1-27. pdfIndia, Andhra Pradeshlamprophyres

Abstract: Geochemical and petrological characteristics of lamprophyre dykes at Kalagalla intruded into the auriferous schistose rocks of the Ramagiri- Penakacherla Schist Belt, Anantapur district, Andhra Pradesh, India are presented here. The Kalagalla lamprophyre (KGL) is a melanocratic rock exhibiting typical knobby or pustular texture on the surface. The microtextures and mineralogy typical of lamprophyres are obscured by metamorphism; however, it exhibits porphyritic, nemato-granoblastic texture representative of greenschist facies of metamorphism. The rock is sheared and possesses several globules formed by polycrystalline aggregates of calcite rimmed by coronitic subhedral plagioclase and biotite, evidencing its mantle-magmatic origin. The mineral assemblages noticed in thin-sections include amphibole, plagioclase, biotite, phlogopite and calcite ocelli as essential while apatite, zircon, magnetite, ilmenite, Ni-bearing chalcopyrite and pyrite as accessory phases. The SEM-EDS investigation on the accessory minerals revealed accessory sulphide and silicate phases like As-free pyrite, haematitised Ni-bearing chalcopyrite and Ni-As-Co- minerals indicative of sulphidation associated with greenstone auriferous lodes, along with silicates like LREE-bearing titanite partially transformed into leucoxene and oxide phases like magnetite altered to goethite at places. Based on mineral chemistry, whole rock geochemistry, presence of amphibole and dominance of plagioclase, the KGL is classified as a calc-alkaline variety in general and as spessartite in particular possessing shoshonitic affinity. No anomalous chemical composition is noticed in the ocellar calcite. The LREE-bearing titanite appears to be the contributor of LREE enrichment. The high Mg# (77- 79), Ni (153-162 ppm) and Cr (380-470 ppm) support a mantle source. The absence of Eu anomaly reflects lack of plagioclase fractionation. The high Zr/Hf ratio (163-202) indicates absence of crustal contamination and contribution of magmatic carbonate at the source to form ocelli as product of late-stage liquid silicate-carbonate immiscibility of segregation mechanism. The trace and REE patterns (?REE: 326-343 ppm, LREE>HREE) indicate involvement of residual garnet at the source presumably enriched in phlogopite in a ‘subduction-related’ environment.
DS1988-0565
1988
Reddy, R.K.T.Reddy, R.K.T.Microcomputer programs to manage and analyze digitized geological data-applications in exploration modeling #2Computers and Geosciences, Vol. 14, No. 5, pp. 687-698. Database # 17577GlobalComputer, Program- Digitizing -Exploration model
DS1988-0566
1988
Reddy, R.K.T.Reddy, R.K.T.Microcomputer programs to manage and analyze digitized geological data-applications in exploration modeling #1Computers and Geosciences, Vol. 14, No. 5, pp. 687-698. Database # 17478GlobalComputers, Program
DS1991-1405
1991
Reddy, R.K.T.Reddy, R.K.T.Digital analysis of lineaments - a test study on South IndiaComputers and Geosciences, Vol. 17, No. 4, pp. 549-560IndiaComputers, Lineaments
DS201804-0731
2018
Reddy, S.Reddy, S., Saxey, D., Rickard, W., Fougerouse, D.Atom probe microscopy and potential applications to diamond research.4th International Diamond School: Diamonds, Geology, Gemology and Exploration Bressanone Italy Jan. 29-Feb. 2nd., pp. 36-37. abstractTechnologydiamond inclusions
DS2002-0303
2002
Reddy, S.M.Collins, A.S., Reddy, S.M., Mruma, A.Structural setting and U /Pb SHRIMP zircon geochronology of 2.) Ga eclogites, Usagaran Belt:Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.22., p.22.TanzaniaPaleoproterozoic subduction zone metamorphism
DS2002-0304
2002
Reddy, S.M.Collins, A.S., Reddy, S.M., Mruma, A.Structural setting and U /Pb SHRIMP zircon geochronology of 2.) Ga eclogites, Usagaran Belt:Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.22., p.22.TanzaniaPaleoproterozoic subduction zone metamorphism
DS200512-0099
2004
Reddy, S.M.Bodorkos, S., Reddy, S.M.Proterozoic cooling and exhumation of the northern central Halls Creek Orogen, Western Australia: constraints from a reconnaissance 40 Ar 39 Ar study.Australia Journal of Earth Sciences, Vol. 51, 4, pp. 591-609.AustraliaGeochronology
DS200912-0618
2009
Reddy, S.M.Reddy, S.M., Evans, D.A.D.Paleoproterozoic supercontinents and global evolution: correlations from core to atmosphere.Geological Society of London Special Publication, No. 323, pp. 1-26.MantleTectonics
DS200912-0619
2009
Reddy, S.M.Reddy, S.M., Mazumder, R., Evans, D.A.D., Collins, A.S.Paleoproterozoic supercontinents and global evolution.Geological Society of London Special Publication, www.geolsoc.org.uk/bookshopGlobalBook
DS201112-1048
2011
Reddy, S.M.Timms, N.E., Kinny, P.D., Reddy, S.M., Evans, K., Clark, C., Healy, D.Relationship among titanium, rare earth elements, U-Pb ages and deformation microstructures in zircon: implications for Ti in zircon thermometry.Chemical Geology, Vol. 280, 1-2, pp. 33-46.Russia, SiberiaXenoliths
DS201711-2531
2017
Reddy, S.M.Timms, N.E., Erickson, T.M., Zanetti, M.R., Pearce, M.A., Cayron, C., Cavosie, A.J., Reddy, S.M., Wittman, A., Carpenter, P.K.Cubic zirconia in >2370 C impact melt records Earth's hottest crust.Earth and Planetary Science Letters, Vol. 478, pp. 52-58.Canada, QuebecMistastin crater

Abstract: Bolide impacts influence primordial evolution of planetary bodies because they can cause instantaneous melting and vaporization of both crust and impactors. Temperatures reached by impact-generated silicate melts are unknown because meteorite impacts are ephemeral, and established mineral and rock thermometers have limited temperature ranges. Consequently, impact melt temperatures in global bombardment models of the early Earth and Moon are poorly constrained, and may not accurately predict the survival, stabilization, geochemical evolution and cooling of early crustal materials. Here we show geological evidence for the transformation of zircon to cubic zirconia plus silica in impact melt from the 28 km diameter Mistastin Lake crater, Canada, which requires super-heating in excess of 2370?°C. This new temperature determination is the highest recorded from any crustal rock. Our phase heritage approach extends the thermometry range for impact melts by several hundred degrees, more closely bridging the gap between nature and theory. Profusion of >2370?°C superheated impact melt during high intensity bombardment of Hadean Earth likely facilitated consumption of early-formed crustal rocks and minerals, widespread volatilization of various species, including hydrates, and formation of dry, rigid, refractory crust.
DS201812-2808
2018
Reddy, S.M.Farahbakhsh, E., Chandra, R., Olierook, H.K.H., Scalzo, R., Clark, C., Reddy, S.M., Muller, R.D.Computer vision based framework for extracting geological lineaments from optical remote sensing data.researchgate.com, arXiv:1810.02320v1 17p. Oct 4.Globallineaments

Abstract: The extraction of geological lineaments from digital satellite data is a fundamental application in remote sensing. The location of geological lineaments such as faults and dykes are of interest for a range of applications, particularly because of their association with hydrothermal mineralization. Although a wide range of applications have utilized computer vision techniques, a standard workflow for application of these techniques to mineral exploration is lacking. We present a framework for extracting geological lineaments using computer vision techniques which is a combination of edge detection and line extraction algorithms for extracting geological lineaments using optical remote sensing data. It features ancillary computer vision techniques for reducing data dimensionality, removing noise and enhancing the expression of lineaments. We test the proposed framework on Landsat 8 data of a mineral-rich portion of the Gascoyne Province in Western Australia using different dimension reduction techniques and convolutional filters. To validate the results, the extracted lineaments are compared to our manual photointerpretation and geologically mapped structures by the Geological Survey of Western Australia (GSWA). The results show that the best correlation between our extracted geological lineaments and the GSWA geological lineament map is achieved by applying a minimum noise fraction transformation and a Laplacian filter. Application of a directional filter instead shows a stronger correlation with the output of our manual photointerpretation and known sites of hydrothermal mineralization. Hence, our framework using either filter can be used for mineral prospectivity mapping in other regions where faults are exposed and observable in optical remote sensing data.
DS201904-0763
2019
Reddy, S.M.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.
DS201905-1028
2018
Reddy, S.M.Farahbakhsh, E., Chandra, R., Olierook, H.K.H., Scalzo, R., Clark, C., Reddy, S.M., Muller, R.D.Computer vision based framework for extracting geological lineaments from optical remote sensing data.arXiv.1810,02320vl, researchgate 17p.Australialineaments
DS1988-0498
1988
Reddy, T.A.K.Nayak, S.S., Viswanathan, C.V.K., Reddy, T.A.K., Rao, B.K.N.New find of kimberlitic rocks in Andhra Pradesh near Maddur,MahaboobnagarDistrictJournal of Geological Society India, Vol. 31, No. 3, March pp. 343-346IndiaBlank
DS1998-1206
1998
Reddy, T.A.K.Rao, K.R.P., Reddy, T.A.K., Rao, N.V.Geology, petrology and geochemistry of Narayanpet kimberlites in Andhra Pradesh and Karnataka.Journal of Geological Society India, Vol. 52, No. 6, Dec. pp. 663-76.India, South IndiaKimberlites, Deposit - Narayanpet, Krishna, Bhima Rivers
DS2003-1148
2003
Reddy, T.A.K.Reddy, T.A.K., Sridhar, M., Ravi, S., Chakravarthi, V., Neelakantam, S.Petrography and geochemistry of the Krishna lamproite field, Andhra PradeshGeological Society of India Journal, Vol. 61, 2, pp. 131-46.India, Andhra PradeshLamproites
DS200612-1125
2001
Reddy, T.A.K.Rao, K.R.P., Nayak, S.S., Reddy, T.A.K., Dhakate, M.V., Chowdary, V.S., Ravi, S., Suresh, G., Rao, K.S.B.Geology, petrology, geochemistry and mineral chemistry of new kimberlite fields in the Wajrakarur kimberlite field, Anantapur district, Andhra Pradesh.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 593-602.India, Andhra PradeshGeochemistry
DS200612-1146
2005
Reddy, T.A.K.Reddy, T.A.K., Ravi, S.Geology and petrology of the lamproite occurrences in Andhra Pradesh.Geological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 60-62.India, Andhra Pradesh, Dharwar CratonLamproite
DS200812-0850
2008
Reddy, T.A.K.Parthasarathy, G., Reddy, T.A.K.Electrical resistivity of Ti rich phlogopite under mantle pressures.Goldschmidt Conference 2008, Abstract p.A725.IndiaLamproite
DS200612-1226
2005
Reddy, V.A.Sastry, C.A., Rama Rao, G., Prasad, G.J.S., Reddy, V.A.Electro probe micro analysis of indicator minerals from kimberlites of Andhra Pradesh and Karnataka.Geological Survey of India, Bulletin, C6, 282p. Cited in GJSI. 67, 2, p. 280.India, Andhra Pradesh, KarnatakaGeochemistry
DS200612-0484
2006
Reddy, V.D.Goutham, M.R., Raghubabu, K., Prasad, C.V.R.K., Subbarao, K.V., Reddy, V.D.A Neoproterozoic geomagnetic field reversal from the Kurnool Group, India: implications for stratigraphic correlation and formation of Gondwana.Journal of the Geological Society of India, Vol. 67, 2, pp. 221-233.Asia, IndiaGeophysics - magnetics, paleomagnetism
DS201512-1937
2015
Redfearn, M.Mackay, D.A.R., Simandl, G.J.,Ma, W., Gravel, J., Redfearn, M.Indicator minerals in exploration for speciality metal deposits: a QEMSCAN approach.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 211-218.TechnologyRare earths

Abstract: Quantitative Evaluation of Materials by Scanning electron microscopy (QEMSCAN®) was used to assess carbonatite indicator minerals in fl uvial sediments from the drainage area of the Aley carbonatite, in north-central British Columbia. QEMSCAN® is a viable method for rapid detection and characterization of carbonatite indicator minerals with minimal processing other than dry sieving. Stream sediments from directly above, and up to 11 km downstream, of the carbonatite deposit were selected for this indicator mineral study. The geology of the Aley carbonatite is described by Mäder (1986), Kressal et al. (2010), McLeish (2013), Mackay and Simandl (2014), and Chakhmouradian et al. (2015). Traditional indicator mineral exploration methods use the 0.25-2.0 mm size fraction of unconsolidated sediments (Averill, 2001, 2014; McCurdy, 2006, 2009; McClenaghan, 2011, 2014). Indicator minerals are detectable by QEMSCAN® at particle sizes smaller than those used for hand picking (<0.25 mm). Pre-concentration (typically by shaker table) is used before heavy liquid separation, isodynamic magnetic separation, optical identifi cation using a binocular microscope, and hand picking (McClenaghan, 2011). Following additional sieving, the 0.5-1 and 1-2 mm fractions are hand picked for indicator minerals while the 0.25-0.5 mm fraction is subjected to paramagnetic separation before hand picking (Averill, 2001; McClenaghan, 2011). Hand picking indicator minerals focuses on monomineralic grains, and composite grains may be lost during processing. Composite grains are diffi cult and time consuming to hand pick and characterize using optical and Scanning Electron Microscopy (SEM) methods. A single grain mount can take 6-12 hours to chemically analyse (Layton- Matthews et al., 2014). Detailed sample analysis using the QEMSCAN® Particle Mineral Analysis routine allows for 5-6 samples to be analyzed per day. When only mineral identifi cation and mineral concentrations and counts are required, the use of a Bulk Mineral Analysis routine reduces the analysis time from ~4 hours to ~30 minutes per sample.
DS201605-0864
2016
Redfearn, M.Mackay, D.A.R., Simandl, G.J., Ma, W., Redfearn, M., Gravel, J.Indicator mineral-based exploration for carbonatites and related specialty metal deposits - a QEMSCAN orientation survey, British Columbia. Aley, Lonnie, WicheedaJournal of Geochemical Exploration, Vol. 165, pp. 159-173.Canada, British ColumbiaGeochemistry - carbonatites

Abstract: This orientation survey indicates that Quantitative Evaluation of Materials by Scanning electron microscopy (QEMSCAN®) is a viable alternative to traditional indicator mineral exploration approaches which involve complex processing followed by visual indicator mineral hand-picking with a binocular microscope. Representative polished smear sections of the 125-250 ?m fraction (dry sieved and otherwise unprocessed) and corresponding Mozley C800 table concentrates from the drainages of three carbonatites (Aley, Lonnie, and Wicheeda) in the British Columbia Alkaline Province of the Canadian Cordillera were studied. Polished smear sections (26 × 46 mm slide size) contained an average of 20,000 exposed particles. A single section can be analyzed in detail using the Particle Mineral Analysis routine in approximately 3.5-4.5 h. If only mineral identification and mineral concentrations are required, the Bulk Mineral Analysis routine reduces the analytical time to 30 min. The most useful carbonatite indicator minerals are niobates (pyrochlore and columbite), REE-fluorocarbonates, monazite, and apatite. Niobate minerals were identified in the 125-250 ?m fraction of stream sediment samples more than 11 km downstream from the Aley carbonatite (their source) without the need for pre-concentration. With minimal processing by Mozley C800, carbonatite indicator minerals were detected downstream of the Lonnie and Wicheeda carbonatites. The main advantages of QEMSCAN® over the traditional indicator mineral exploration techniques are its ability to: 1) analyze very small minerals, 2) quickly determine quantitative sediment composition and mineralogy by both weight percent and mineral count, 3) establish mineral size distribution within the analyzed size fraction, and 4) determine the proportions of monomineralic (liberated) grains to compound grains and statistically assess mineral associations in compound grains. One of the key advantages is that this method permits the use of indicator minerals based on their chemical properties. This is impossible to accomplish using visual identification.
DS200612-0328
2006
Redfern, A.T.Deuss, A., Redfern, A.T., Chambers, K., Woodhouse, J.H.The nature of the 660 kilometer discontinuity in Earth's mantle from global seismic observations of PP Precursors.Science, Vol. 311, 5758, Jan. 13, pp. 198-200.MantleGeophysics - seismics, core mantle boundary
DS201906-1361
2019
Redfern, S.Wang, W., Walter, M.J., Peng, Y., Redfern, S., Wu, Z.Constraining olivine abundance and water content of the mantle at the 410 km discontinuity from the elasticity of olivine and wadsleyite.Earth and Planetary Science Letters, Vol. 519, pp. 1-11.Mantleolivine

Abstract: Velocity and density jumps across the 410-km seismic discontinuity generally indicate olivine contents of ?30 to 50 vol.% on the basis of the elastic properties of anhydrous olivine and wadsleyite, which is considerably less than the ?60% olivine in the widely accepted pyrolite model for the upper mantle. A possible explanation for this discrepancy is that water dissolved in olivine and wadsleyite affects their elastic properties in ways that can reconcile the pyrolitic model with seismic observations. In order to more fully constrain the olivine content of the upper mantle near the 410-km discontinuity, and to place constraints on the mantle water content at this depth, we determined the full elasticity of hydrous wadsleyite at the P-T conditions of the discontinuity based on density functional theory calculations. Together with previous determinations for the effect of water on olivine elasticity, we simultaneously modeled the density and seismic velocity jumps (??, , ) across the olivine-wadsleyite transition. Our models allow for several scenarios that can well reproduce the density and seismic velocity jumps across the 410-km discontinuity when compared to globally averaged seismic models. When the water content of olivine and wadsleyite is assumed to be equal as in a simple binary system, our modeling indicates a best fit for low water contents (<0.1 wt.%) with an olivine proportion of ?50%, suggesting a relatively dry, non-pyrolitic mantle at depths of the 410-km discontinuity. However, our modeling can be reconciled with a pyrolitic mantle if the water content in wadsleyite is ?0.9 wt.% and that in olivine is at its storage capacity of ?500-1500 ppm. The result would be consistent with a hydrous melt phase produced at depths just above the phase transition.
DS201907-1583
2019
Redfern, S.Wang, W., Walter, M.J., Peng, Y., Redfern, S., Wu, Z.Constraining olivine abundance and water content of the mantle at the 410 km discontinuity from the elasticity of olivine and wadsleyite.Earth and Planetary Science Letters, Vol. 519, pp. 1-11.Mantleboundary

Abstract: Velocity and density jumps across the 410-km seismic discontinuity generally indicate olivine contents of ?30 to 50 vol.% on the basis of the elastic properties of anhydrous olivine and wadsleyite, which is considerably less than the ?60% olivine in the widely accepted pyrolite model for the upper mantle. A possible explanation for this discrepancy is that water dissolved in olivine and wadsleyite affects their elastic properties in ways that can reconcile the pyrolitic model with seismic observations. In order to more fully constrain the olivine content of the upper mantle near the 410-km discontinuity, and to place constraints on the mantle water content at this depth, we determined the full elasticity of hydrous wadsleyite at the P-T conditions of the discontinuity based on density functional theory calculations. Together with previous determinations for the effect of water on olivine elasticity, we simultaneously modeled the density and seismic velocity jumps (??, , ) across the olivine-wadsleyite transition. Our models allow for several scenarios that can well reproduce the density and seismic velocity jumps across the 410-km discontinuity when compared to globally averaged seismic models. When the water content of olivine and wadsleyite is assumed to be equal as in a simple binary system, our modeling indicates a best fit for low water contents (<0.1 wt.%) with an olivine proportion of ?50%, suggesting a relatively dry, non-pyrolitic mantle at depths of the 410-km discontinuity. However, our modeling can be reconciled with a pyrolitic mantle if the water content in wadsleyite is ?0.9 wt.% and that in olivine is at its storage capacity of ?500-1500 ppm. The result would be consistent with a hydrous melt phase produced at depths just above the phase transition.
DS2002-1322
2002
Redfern, S.A.T.Redfern, S.A.T.Neutron powder diffraction of minerals at high pressures and temperatures: some recent technical ...European Journal of Mineralogy, Vol.14,2,pp.251-62.GlobalTechnology - not specific to diamonds, Technical developments and scientific applications
DS200712-0111
2007
Redfern, S.A.T.Bromiley, G.D., Redfern, S.A.T.The role of rutile/TiO2(II) during melting of ancient, subducted oceanic crust: implications for oceanic island magmatism.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 93-94.MantleMagmatism
DS200712-0112
2007
Redfern, S.A.T.Bromiley, G.D., Redfern, S.A.T.The role of rutile/TiO2(II) during melting of ancient, subducted oceanic crust: implications for oceanic island magmatism.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 93-94.MantleMagmatism
DS200712-1087
2007
Redfern, S.A.T.Tomlinon, E.L., McMillan, P.F., Zhang, M., Jones, A.P., Redfern, S.A.T.Quartz bearing C-O-H fluid inclusions diamond: retracing the pressure-temperature path in the mantle using calibrated high temperature IR spectroscopy.Geochimica et Cosmochimica Acta, on line in press available, 10p.Africa, Democratic Republic of CongoDeposit - Mbuji Mayi - mineralogy
DS200812-0143
2008
Redfern, S.A.T.Bromiley, G.D., Redfern, S.A.T.The role of TiO2 phases during melting of subduction modified crust: implications for deep mantle melting.Earth and Planetary Science Letters, Vol. 267, 1-2, pp.301-308.MantleMelting
DS2002-1320
2002
Redfern S.A.T.Redfern S.A.T.Neutron powder diffraction of minerals at high pressures and temperatures: some recent technical ...European Journal of Mineralogy, Vol. 14,pp.251-61., Vol. 14,pp.251-61.GlobalMineral behaviour - techniques, Scientific applications - not specific to diamonds
DS2002-1321
2002
Redfern S.A.T.Redfern S.A.T.Neutron powder diffraction of minerals at high pressures and temperatures: some recent technical ...European Journal of Mineralogy, Vol. 14,pp.251-61., Vol. 14,pp.251-61.GlobalMineral behaviour - techniques, Scientific applications - not specific to diamonds
DS1994-0633
1994
Redfield, T.F.Goldstrand, P.M., Fitzgerald, P.G., Redfield, T.F., Stump, E.Stratigraphic evidence for Ross Orogeny in Ellsworth Mountains, WestAntarctica: implication for evolution of paleo-Pacific margin of GondwanaGeology, Vol. 2, No. 5, May pp. 427-430AntarcticaStratigraphy
DS2002-1608
2002
Redfield, T.F.Torsvik, T.H., Van der Voo, R., Redfield, T.F.Relative hotspot motions versus True Polar WanderEarth and Planetary Science Letters, Vol. 202, 2, pp. 185-200.MantleHot spots
DS200512-0898
2005
Redfield, T.F.Redfield, T.F., Osmundsen, P.T., Hendriks, B.W.H.The role of fault reactivation and growth in the uplift of western Fennoscandia.Journal of the Geological Society, Vol. 162, 6, pp. 1013-1030.Europe, FinlandTectonics
DS200512-1083
2005
Redhammer, G.J.Thompson, R.M., Downs, R.T., Redhammer, G.J.Model pyroxenes III: volume of C2/c pyroxenes at mantle P,T, and x.American Mineralogist, Vol. 90, Nov-Dec. pp. 1840-1851.MantleMantle minerals, chemistry
DS201710-2258
2017
Redina, A.A.Prokopyev, I.R., Doroshkevich, A.G., Redina, A.A.Magnetite apatite dolomitic rocks of Ust-Chulman ( Aldan Shield, Russia): Seligdar type carbonatites?Mineralogy and Petrology, in press available 10p.Russiacarbonatite

Abstract: The Ust-Chulman apatite ore body is situated within the Nimnyrskaya apatite zone at the Aldan shield in Russia. The latest data confirm the carbonatitic origin of the Seligdar apatite deposit (Prokopyev et al. in Ore Geol Rev 81:296-308, 2017). The results of our investigations demonstrate that the magnetite-apatite-dolomitic rocks of the Ust-Chulman are highly similar to Seligdar-type dolomitic carbonatites in terms of the mineralogy and the fluid regime of formation. The ilmenite and spinel mineral phases occur as solid solutions with magnetite, and support the magmatic origin of the Ust-Chulman ores. The chemical composition of REE- and SO3-bearing apatite crystals and, specifically, monazite-(Ce) mineralisation and the formation of Nb-rutile, late hydrothermal sulphate minerals (barite, anhydrite) and haematite are typical for carbonatite complexes. The fluid inclusions study revealed similarities to the evolutionary trend of the Seligdar carbonatites that included changes of the hydrothermal solutions from highly concentrated chloride to medium-low concentrated chloride-sulphate and oxidized carbonate-ferrous.
DS201802-0260
2018
Redina, A.A.Prokopyev, I.R., Doroshkevich, A.G., Redina, A.A., Obukhov, A.V.Magnetite apatite dolomitic rocks of Ust Chulman ( Aldan Shield, Russia): Seligdar type carbonatites?Mineralogy and Petrology, in press available, 10p.Russia, Aldan shieldcarbonatites

Abstract: The Ust-Chulman apatite ore body is situated within the Nimnyrskaya apatite zone at the Aldan shield in Russia. The latest data confirm the carbonatitic origin of the Seligdar apatite deposit (Prokopyev et al. in Ore Geol Rev 81:296-308, 2017). The results of our investigations demonstrate that the magnetite-apatite-dolomitic rocks of the Ust-Chulman are highly similar to Seligdar-type dolomitic carbonatites in terms of the mineralogy and the fluid regime of formation. The ilmenite and spinel mineral phases occur as solid solutions with magnetite, and support the magmatic origin of the Ust-Chulman ores. The chemical composition of REE- and SO3-bearing apatite crystals and, specifically, monazite-(Ce) mineralisation and the formation of Nb-rutile, late hydrothermal sulphate minerals (barite, anhydrite) and haematite are typical for carbonatite complexes. The fluid inclusions study revealed similarities to the evolutionary trend of the Seligdar carbonatites that included changes of the hydrothermal solutions from highly concentrated chloride to medium-low concentrated chloride-sulphate and oxidized carbonate-ferrous.
DS201905-1068
2019
Redina, A.A.Prokopyev, I.R., Doroshkevich, A.G., Sergeev, S.A., Ernst, R.E., Ponomarev, J.D., Redina, A.A., Chebotarev, D.A., Nikolenko, A.M., Dultsev, V.F., Moroz, T.N., Minakov, A.V.Petrography, mineralogy and SIMS U-Pb geochronology of 1.0 - 1.8 Ga carbonatites and associated alkaline rocks of the Central Aldan magnesiocarbonatite province ( South Yakutia, Russia).Mineralogy and Petrology, Doi.org/a0.1007/ s00710-019-00661-3 24p.Russiacarbonatites
DS201906-1339
2019
Redina, A.A.Prokopyev, I.R., Doroshkevich, A.G., Sergeev, S.A., Ernst, R.E., Ponomarev, J.D., Redina, A.A., Chebotarev, D.A., Nikolenko, A.M., Dultsev, V.F., Moroz, T.N., Minakov, A.V.Petrography, mineralogy and SIMS U-Pb geochronology of 1.9-1.8 Ha carbonatites and associated alkaline rocks of the Central-Aldan magnesiocarbonatite province ( South Yakutia, Russia).Mineralogy and Petrology, Vol. 113, pp. 329-352.Russia, Yakutiacarbonatites
DS202008-1426
2020
Redina, A.A.Nikolenko, A.M., Doroshkevich, A.G., Ponomarchuk, A.V., Redina, A.A., Prokopyev, I.R., Vladykin, N.V., Nikolaeva, I.V.Ar-Ar geochronology and petrogenesis of the Mushgai-Khudag alkaline-carbonatite complex 9 southern Mongolia).Lithos, Vol. 372-372, 105675 15p. PdfAsia, Mongoliacarbonatite

Abstract: The Mushgai-Khudag alkaline?carbonatite complex, located in southern Mongolia within the Central Asian Orogenic Belt (CAOB), comprises a broad range of volcanic and subvolcanic alkaline silicate rocks (melanephelinite-trachyte and shonkinite-alkaline syenite, respectively). Magnetite-apatite rocks, carbonatites, and fluorite mineralization are also manifested in this area. The complex formed between 145 and 133 Ma and is contemporaneous with late Mesozoic alkaline-carbonatite magmatism within the CAOB. Major and trace element characteristics of silicate rocks in the Mushgai-Khudag complex imply that these rocks were formed by the fractional crystallization of alkaline ultramafic parental magma. Magnetite-apatite rocks may be a product of silicate-Ca-Fe-P liquid immiscibility that took place during the alkaline syenite crystallization stage. The Mushgai-Khudag rocks have variable and moderately radiogenic Sr (87Sr/86Sr(i) = 0.70532-0.70614), ?Nd(t) = ?1.23 to 1.25) isotopic compositions. LILE/HFSE values and SrNd isotope compositions indicate that the parental melts of Mushgai-Khudag were derived from a lithospheric mantle source that was affected by a metasomatic agent in the form a mixture of subducted oceanic crust and its sedimentary components. The ?18OSMOW and ?18CPDB values for calcites in carbonatites range from 16.8‰ to 19.2‰ and from ?3.9‰ to 2.0‰, respectively. CO covariations in calcites of the Mushgai-Khudag carbonatites can be explained by the slight host limestone assimilation.
DS1991-1420
1991
Reding, L.M.Richardson, R.M., Reding, L.M.North American plate dynamics #1Journal of Geophysical Research, Vol. 96, No. B7, July 10, pp. 12, 201-12, 224North AmericaTectonics, Plate
DS1991-1421
1991
Reding, L.M.Richardson, R.M., Reding, L.M.North American plate dynamics #2Journal of Geophysical Research, Vol. Paper # 91JB00958United States, CanadaTectonics, Plates, Paper
DS1995-0371
1995
Redmann, R.E.Crowder, A.A., Ripley, E.A., Redmann, R.E.Environmental effects of mining #3St. Lucie Press, 300p. $ 60.00United StatesEnvironment- legal, mining, Table of contents
DS200712-0545
2007
Redmond, H.L.King, S.D., Redmond, H.L.The structure of thermal plumes and geophysical observations.Plates, plumes and Planetary Processes, pp. 103-120.MantleGeophysics - seismics
DS201707-1360
2017
Reece, J.Reis, N.J., Nadeau, S., Fraga, L.M., Menezes Betiollo, L., Telma Lins Faraco, M., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil Guyana border in the Guiana shield, northern Amazonian craton - results of the Brazil Guyana geology and geodiversity mapping project.Brazil Journal of Geology, Vol. 47, 1, pp. 43-57.South America, Brazil, Guyanacraton

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil?Guyana border zone allowed reviewing and in? tegrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú?Ireng River between Mount Roraima (the tri? ple?border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro?Burro Group of Guyana.
DS201810-2371
2018
Reece, J.Reis, N.J., Nadeau, S., Fraga, L.M., Betiollo, L.M., Faraco, M.T.L., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil-Guyana border in the Guiana shield, northern Amazonian craton- results of the Brazil-Guyana geology and geodiversity mapping project.Brazilian Journal of Geology, Vol. 47, 1, pp. 43-57.South America, Brazil, Guyanacraton

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil?Guyana border zone allowed reviewing and in? tegrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú?Ireng River between Mount Roraima (the tri? ple?border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro?Burro Group of Guyana.
DS201904-0772
2017
Reece, J.Reis, N.J., Nadeau, S., Fraga, L.M., Menezes Betiollo, L., Telma Lins, Faraco, M., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil-Guyana border in the Guiana shield, northern Amazonian craton - results of the Brazil Guyana geology and geodiversity mapping project.Brazilian Journal of Geology, Vol. 41, 1, pp. 43-57.South America, Brazil, GuyanaGuiana shield

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil-Guyana border zone allowed reviewing and integrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú-Ireng River between Mount Roraima (the triple-border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro-Burro Group of Guyana.
DS201312-0293
2013
ReedGao, S.S., Liu, Reed, Yu, Massinque, Mdala, Moidaki, Mutamina, Atekwana, Ingate, ReuschSeismic arrays to study African Rift initiation.EOS Transaction of AGU, Vol. 94, 24, June 11, pp. 213-214.Africa, southern AfricaGeophysics - seismics
DS1997-0947
1997
Reed, A.Reed, A.Canadian reserves of selected major metals, and recent productiondecisionsCanadian Minerals Yearbook 1996, 15pCanadaEconomics, Exploration, mining, discoveries, legal
DS201512-1997
2015
Reed, C.A.Yu, Y., Liu, K.H., Reed, C.A., Moidaki, M., Mickus, K., Atekwana, E.A., Gao, S.S.A joint receiver function and gravity study of crustal structure beneath the incipient Okavango Rift, Botswana.Geophysical Research Letters, Vol. 42, 20, pp. 8398-8405.Africa, BotswanaGeophysics - gravity

Abstract: Rifting incorporates the fundamental processes concerning the breakup of continental lithosphere and plays a significant role in the formation and evolution of sedimentary basins. In order to decipher the characteristics of rifting at its earliest stage, we conduct the first teleseismic crustal study of one of the world's youngest continental rifts, the Okavango Rift Zone (ORZ), where the magma has not yet breached the surface. Results from receiver function stacking and gravity modeling indicate that the crust/mantle boundary beneath the ORZ is uplifted by 4-5 km, and the initiation of the ORZ is closely related to lithospheric stretching. Possible decompression melting of the subcrustal lithosphere occurs beneath the ORZ, as evidenced by a relatively low upper mantle density based on the gravity modeling.
DS1940-0217
1949
Reed, D.F.Reed, D.F.Investigation of Magnet Cove Rutile Deposit, Hot Spring County, Arkansaw.United States Bureau of Mines Report INV., No. 4593, 9P.United States, Gulf Coast, Arkansas, Hot Spring CountyRutile
DS1940-0218
1949
Reed, D.F.Reed, D.F.Investigation of Christy Titanium Deposit, Hot Spring County,arkansaw.United States Bureau of Mines Report INV., No. 4592, 10P.United States, Gulf Coast, Arkansas, Hot Spring CountyTitanium
DS1900-0350
1905
Reed, E.A.Reed, E.A.The Precious Stone Industry of the U.S.A.Scientific American., Vol. 59, APRIL 8TH. PP. 24470-24471.United StatesGemstones
DS1989-1255
1989
Reed, J.Reed, J.Polygon- delimited gridding, contouringGeotimes, Vol. 34, No. 9, September pp. 16-17GlobalComputer, Brief overview - Polygons
DS1930-0175
1934
Reed, J.C.Reed, J.C.Geology of the Potsdam QuadrangleNew York State Mus. Bulletin., No. 297, 98P.United States, Appalachia, New YorkGeology
DS1993-1285
1993
Reed, J.C.Reed, J.C., Bickford, M.E., Houston, R.S., Link, P.K., Rankin, D.W.Precambrian: conterminous U.SGeological Society of America DNAG Volume, No. C-2, 700p. approx. $ 100.00United StatesBook -table of contents, Precambrian
DS1987-0608
1987
Reed, J.C.JrReed, 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
DS1987-0607
1987
Reed, J.C.Jr.Reed, J.C.Jr.Precambrian geology of the United States (US)Episodes, Vol. 10, No. 4, December pp. 243-247United StatesOverview
DS1993-0021
1993
Reed, J.C.Jr.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
DS1975-1097
1979
Reed, J.E.Keller, E.G., Russel, D.R., Hinze, W.J., Reed, J.E., Geraci, P.C.A Bouguer Gravity Map of a Portion of the Central Midcontinent.Eos, Vol. 61, No. 5, P. 48.GlobalMid-continent
DS1980-0188
1980
Reed, J.E.Keller, G.R., Russell, D.R., Hinze, W.J., Reed, J.E., Geraci, P.Bouguer Gravity Anomaly Map of East Central Midcontinent Of the United States.National Technical Information Service NUREG CR/1663, 12P.GlobalMid-continent
DS1980-0287
1980
Reed, J.E.Reed, J.E., Hinze, W.J., Braile, L.W., Russell, D.R.Enhanced Gravity and Magnetic Anomaly Maps of the East Central Midcontintent.Geological Society of America (GSA), Vol. 12, No. 5, P. 254. (abstract.).GlobalMid-continent
DS1983-0307
1983
Reed, J.E.Hinze, W.J., Lidiak, E.G., Reed, J.E., Keller, E.G., Braile, L.W.Geologic Significance of Regional Gravity and Magnetic Anomalies in the East Central Midcontinent.Geophysics, Vol. 48, No. 4, P. 449. (abstract.).GlobalMid-continent
DS1986-0396
1986
Reed, L.E.Janse, A.J.A., Downie, I.F., Reed, L.E., Sinclair, I.G.L.Alkaline diatremes in the Hudson Bay Lowlands, Canada,explorationmethods, petrology and geochemistryProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 469-471OntarioDiamond exploration
DS1989-0699
1989
Reed, L.E.Janse, A.J.A., Downie, I.F., Reed, L.E., Sinclair, I.G.L.Alkaline intrusions in the Hudson Bay Lowlands, Canada: explorationmethods, petrologyGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 1192-1203OntarioExploration techniques, Geophysics, Petrology
DS1991-1406
1991
Reed, L.E.Reed, L.E.Geophysics in mining exploration -applications to base metals, Kimberlite and goldPaper for presentation at the Hailebury School of Mines, O.E. Walli, 28pOntarioGeophysics, Kimberlites
DS1991-1407
1991
Reed, L.E.Reed, L.E., Sinclair, I.G.L.The search for kimberlite in the James Bay Lowlands of OntarioThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 84, No. 947, March pp. 132-139OntarioGeophysics -kimberlite exploration, Geochemistry -kimberlite exploration
DS1993-1286
1993
Reed, L.E.Reed, L.E.Exploration for kimberlite using magneticsThe Gangue, MDD Newsletter, Issue No. 43, September pp. 1-2.GlobalGeophysics -magnetics, Kimberlites
DS1993-1287
1993
Reed, L.E.Reed, L.E.The application of geophysics to exploration for diamondsMid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 21-26.OntarioGeophysics
DS1993-1288
1993
Reed, L.E.Reed, L.E.The geophysics of kimberlitesProspectors and Developers Diamond Workshop, held March 27th, Toronto, 14p. Inc, article by Reed The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Vol. 84, 947, March91OntarioGeophysics, Case histories
DS200712-0881
2007
Reed, L.E.Reed, L.E., Witherly, K.E.50 years of kimberlite geophysics, a review.Proceedings of Exploration 07 edited by B. Milkereit, pp. 679-689.TechnologyGeophysics - diamond - review
DS200912-0620
2007
Reed, L.E.Reed, L.E., Witherly, K.E.50 years of kimberlite geophysics, a review.Exploration 2007, 11p.GlobalGeophysics - review of methods
DS1991-1408
1991
Reed, R.C.Reed, R.C.Economic geology and history of metallic minerals in the northern Peninsula of MichiganGeological Society of America (GSA) Special Publication Paper, No. 256, pp. 13-52MichiganMetallogeny, Not specific to diamonds
DS1988-0478
1988
Reed, S.J.B.Mitchell, R.H., Reed, S.J.B.Ion microprobe determination of rare earth elements in perovskite From kimberlites and alnoitesMineralogical Magazine, Vol. 522, No. 366, pp. 331-339GlobalAlnoite
DS1989-1256
1989
Reed, S.J.B.Reed, S.J.B.Ion microprobe analysis- a review of geological applicationsMineralogical Magazine, Vol. 53, pp. 3-24. Database # 17793GlobalReview paper, Ion microprobe
DS1991-1613
1991
Reed, S.J.B.Smith, D.G.W., St. Jorre, L. de, Reed, S.J.B., Long, J.V.P.Zonally metamictized and other zircons from Thor Lake, NorthwestTerritoriesCanadian Mineralogist, Vol. 29, No. 2, June pp. 301-310Northwest TerritoriesRare earths, Deposit -Thor Lake
DS1995-1556
1995
Reed, S.J.B.Reed, S.J.B.Electron microprobe analysis and scanning electron microscopy in geologyCambridge University of Press, Paperback $ 30.00GlobalMicroscopy, Book -ad
DS1996-1135
1996
Reed, S.J.B.Potts, P.J., Bowles, J.F., Reed, S.J.B., Cave, M.R.Microprobe techniques in the earth sciencesChapman Hall, MSA., MSA No. 6, 420p. approx. 80.00 United StatesGlobalBook - table of contents, Microprobe techniques, review
DS1996-1136
1996
Reed, S.J.B.Potts, P.J., Bowles, J.F.W., Reed, S.J.B., Cave, M.R.Microprobe techniques in the earth sciencesMineralogical Soc. Series, No. 6, 410p. approx. $60.00USGlobalMicroprobe techniques, Various chapters techniques - not specific to diamond
DS1996-1158
1996
Reed, S.J.B.Rao, C.N.V., Reed, S.J.B., Beattie, P.D.Larnitic kirschsteinite from the Kotakonda kimberlite, Andhra Pradesh, India.Mineralogical Magazine, Vol. 60, pt. 3, June 1, pp. 513-516.IndiaMineralogy, Deposit -Katakonda
DS1998-1220
1998
Reed. S.J.B.Reed. S.J.B., Buckley, A.Rare earth element determination in minerals by electron probemicroanalysis: application of spectrum.Mineralogical Magazine, Vol. 62, 1, Feb. pp. 1-8GlobalGeochemistry - spectrum syntheis, rare earth elements (REE)
DS1975-1196
1979
Reedman, J.H.Reedman, J.H.Traditional Prospecting MethodsLondon; Applied Science Publishing, P. 36; PP. 52-55.GlobalKimberley, Techniques
DS1984-0605
1984
Reedman, J.H.Reedman, J.H.Resources of Phosphate, Niobium, Iron and Other Elements In residual Soils Over the Sukulu Carbonatite Complex, Southeastern Uganda.Economic Geology, Vol. 79, No. 4, JUNE-JULY, PP. 716-724.GlobalRelated Rocks
DS1986-0397
1986
Reef, L.E.Janse, A.J.A., Downie, I.F., Reef, L.E., Sinclair, I.G.L.Alkaline diatremes in the Hudson Bay Lowlands: explorationmethods, mineralogy, petrology and geochemistryFick ( Proceedings Of The Fourth International Kimberlite Conference), Abstract 1pOntario, James Bay LowlandsAlkaline rocks
DS2003-1149
2003
Reefton Mining NL.Reefton Mining NL.Reefton's two streams of diamond feed. Bulk sampling at its Skelton Coast projectAustralia Paydirt, Oct. 29, 1p.NamibiaNews item
DS2003-1176
2003
Reemst, P.Rohrman, M., Van der Beek, P.A., Van der Hilst, R.D., Reemst, P.Timing and mechanisms of North Atlantic Cenozoic uplift: evidence for mantleGeological Society of London, Special Publication, No. 196, pp. 27-44.MantlePlumes
DS200412-1681
2003
Reemst, P.Rohrman, M., Van der Beek, P.A., Van der Hilst, R.D., Reemst, P.Timing and mechanisms of North Atlantic Cenozoic uplift: evidence for mantle upwelling.Geological Society of London, Special Publication, No. 196, pp. 27-44.MantlePlume
DS1983-0440
1983
Rees, C.E.Mcewing, C.E., Rees, C.E., Thode, H.G.Sulphur Isotope Ratios in the Canyon Diablo Metallic Spheroids.Meteoritics, Vol. 18, No. 3, SEPT. 30TH. PP. 171-178.United States, Arizona, Colorado PlateauIsotope, Meteor
DS1970-0812
1973
Rees, D.C.Rees, D.C., Erickson, M.P., Whelan, J.A.Geology and Diatremes of Desert Mountain, UtahUnknown, United States, Utah, Rocky MountainsDiatreme
DS1960-0087
1960
Rees, G.Rees, G.The Geology of the West MarangudziLondon: Ph. D. Thesis, University London., 208P.ZimbabweCarbonatite
DS1993-1289
1993
Rees, M.G.Rees, M.G.Deepwater marine diamonds -the technical and financial challengesConference on Mining Investment in Namibia, March 17-19th., 1993, Abstracts pp. 92.NamibiaMining, Deepwater diamonds
DS201412-0570
2014
Rees, S.McMillan, N.J., Rees, S., Kochelek, K., McManus, C.Geological applications of laser-induced breakdown spectrocopy.Geostandards and Geoanalytical Research, Vol. 38, 3, pp. 329-343.Africa, Tanzania, MadagascarRubies
DS202002-0207
2019
Rees Jones, D.W.Meng, T., Katz, R.F., Rees Jones, D.W.Devolatization of subducting slabs: Part 1: By thermodynamic parameterization and open system effects. ( carbon transport)Geochemistry, Geophysics, Geosystems, Vol. 20, 1, pp. 5667-5690.Mantlesubduction

Abstract: The amount of H2O and CO2 that is carried into deep mantle by subduction beyond subarc depths is of fundamental importance to the deep volatile cycle but remains debated. Given the large uncertainties surrounding the spatio?temporal pattern of fluid flow and the equilibrium state within subducting slabs, a model of H2O and CO2 transport in slabs should be balanced between model simplicity and capability. We construct such a model in a two?part contribution. In this Part I of our contribution, thermodynamic parameterization is performed for the devolatilization of representative subducting materials—sediments, basalts, gabbros, peridotites. The parameterization avoids reproducing the details of specific devolatilization reactions, but instead captures the overall behaviors of coupled (de)hydration and (de)carbonation. Two general, leading?order features of devolatilization are captured: (1) the released volatiles are H2O?rich near the onset of devolatilization; (2) increase of the ratio of bulk CO2 over H2O inhibits overall devolatilization and thus lessens decarbonation. These two features play an important role in simulation of volatile fractionation and infiltration in thermodynamically open systems. When constructing the reactive fluid flow model of slab H2O and CO2 transport in the companion paper Part II, this parameterization can be incorporated to efficiently account for the open?system effects of H2O and CO2 transport.
DS200812-1094
2008
Reese, C.C.Solomatov, V.S., Reese, C.C.Grain size variations in the Earth's mantle and the evolution of primordial heterogeneities.Journal of Geophysical Research, Vol. 113, B7 B7408.MantleGeochemistry
DS200412-1406
2003
Reese, I.Nasdala, L., Brenker, F.E., Glinnemann, J., Hofmeister, W., Gasparik, T., Harris, J.W., Stachel, T., Reese, I.Spectroscopic 2D tomography: residual pressure and strain around mineral inclusions in diamonds.European Journal of Mineralogy, Vol.15, 6, pp. 931-36.TechnologyTechnology - tomography inclusions
DS1990-1069
1990
Reese, J.F.Mosher, S., Reese, J.F.The southern collisional margin of the Precambrian North American craton:the Texas Grenville orogenicbeltGeological Society of America (GSA) Abstracts with programs, South-Central, Vol. 22, No. 1, p. 29GlobalMidcontinent, Tectonics
DS1998-0530
1998
ReevesGraham, S., Lambert, D.D., Smith, C.B., Shee, ReevesRhenium- Osmium (Re-Os) isotope systematics of oxide xenocrysts and peridotite xenoliths From the kimberlites - Argyle7th International Kimberlite Conference Abstract, pp. 265-7.AustraliaMantle - lithosphere, lamproite, Deposit - Argyle
DS1999-0261
1999
ReevesGraham, S., Lambert, D., Shee, S., Smith, C.B., ReevesRe Os isotopic evidence for Archean lithospheric mantle beneath the Kimberley Block, Western Australia.Geology, Vol. 27, No. 5, May pp. 431-34.AustraliaGeochronology, Deposit - Argyle, Seppelt
DS1988-0567
1988
Reeves, C.Reeves, C.Geophysical mapping of Precambrian granite-greenstone terranes as an aid to explorationExploration 87, Proceedings Volume, Ontario Geological Survey, Special Publishing No. 3, pp. 254-266Africa, Australia, Canada, IndiaBrief mention of kimberlite on p. 263 (India), Geophysics
DS2000-0807
2000
Reeves, C.Reeves, C.The geophysical mapping of Mesozoic dike swarms in southern Africa and their origin in disruption GondwanaJournal of African Earth Sciences, Vol. 30, No.3, pp. 499-513.BotswanaDike swarms - Gondwana, Geophysics
DS2000-0808
2000
Reeves, C.Reeves, C., De Wit, M.Making ends meet in Gondwana: retracing the transforms of the Indian Ocean and reconnecting continental shearTerra Nova, Vol. 12, No. 6, Dec.pp. 272-80.India, Madagascar, GondwanaGeochronology, Gondwana, tectonics
DS200912-0621
2009
Reeves, C.Reeves, C.E book on aeromagnetic survey principles, practice and interpretation.Geosoft Publisher, FreeTechnologyBook - geophysics not specific to diamonds
DS201412-0727
2014
Reeves, C.Reeves, C.The position of Madagascar within Gondwana and its movements during Gondwana dispersal.Journal of African Earth Sciences, Vol. 94, pp. 45-57.Africa, MadagascarTectonics
DS201811-2604
2018
Reeves, C.Richetti, P.C., Schmitt, R.S., Reeves, C.Dividing the South American continent to fit a Gondwana reconstruction: A model based on continental geology.Tectonophysics, Vol. 747-748, pp. 79-98.South Americaplate tectonics

Abstract: The South American continental plate has been affected by intraplate deformation since the start of West Gondwana disruption in the Lower Cretaceous (about 140?Ma). That the present shape of South America is not precisely the same as its shape in reassembled Gondwana partly explains the imperfect fits of the conjugate margins of the South Atlantic proposed since the first reconstruction models of the early 20th century. Several attempts at defining subplates within South America have been published but not all take account of existing knowledge of its continental geology. Here a subdivision into eight rigid subplates is proposed, based primarily on geological and tectonic evidence. Our model is tested against three published models of a multi-subplate Africa, as re-shaped to the pre-breakup outline of that continent, by visual fitting and the use of piercing points. The South America blocks were rotated and the Euler poles calculated interactively in reconstruction software. All three proposed fits had overlapping block margins within South America, indicating post-breakup rifting, except for the Transbrasiliano lineament. This NNE-SSW crustal-scale shear zone was used as a boundary for seven of the eight blocks. It is clearly the main intraplate accommodation zone in South America and an important piercing point in relation to the Kandi lineament in West Africa. The other block boundaries correspond to narrow zones with sedimentary basins and/or dyke swarms that have developed since South Atlantic opening. Each fit required a different configuration of the South America subplates since the pre-rift disposition of the African subplates also differ from each other, contributing to the uncertainty in any detailed reassembly.
DS201812-2873
2018
Reeves, C.Richetti, P.C., Schmitt, R.S., Reeves, C.Dividing the South American continent to fit a Gondwana reconstruction: a model based on continental geology.Tectonophysics, Vol. 747-748, pp. 79-98.South Americatectonics

Abstract: The South American continental plate has been affected by intraplate deformation since the start of West Gondwana disruption in the Lower Cretaceous (about 140?Ma). That the present shape of South America is not precisely the same as its shape in reassembled Gondwana partly explains the imperfect fits of the conjugate margins of the South Atlantic proposed since the first reconstruction models of the early 20th century. Several attempts at defining subplates within South America have been published but not all take account of existing knowledge of its continental geology. Here a subdivision into eight rigid subplates is proposed, based primarily on geological and tectonic evidence. Our model is tested against three published models of a multi-subplate Africa, as re-shaped to the pre-breakup outline of that continent, by visual fitting and the use of piercing points. The South America blocks were rotated and the Euler poles calculated interactively in reconstruction software. All three proposed fits had overlapping block margins within South America, indicating post-breakup rifting, except for the Transbrasiliano lineament. This NNE-SSW crustal-scale shear zone was used as a boundary for seven of the eight blocks. It is clearly the main intraplate accommodation zone in South America and an important piercing point in relation to the Kandi lineament in West Africa. The other block boundaries correspond to narrow zones with sedimentary basins and/or dyke swarms that have developed since South Atlantic opening. Each fit required a different configuration of the South America subplates since the pre-rift disposition of the African subplates also differ from each other, contributing to the uncertainty in any detailed reassembly.
DS1970-0586
1972
Reeves, C.V.Reeves, C.V.Rifting in the Kalahari?Nature., Vol. 237, MAY 12TH. PP. 95-96.BotswanaGeotectonics, Seismicity
DS1970-0888
1974
Reeves, C.V.Carruthers, R.M., Reeves, C.V.Botswana Gravity Reference NetGeodesique Bulletin., Vol. 114, PP. 409-418.BotswanaGeophysics
DS1975-0166
1975
Reeves, C.V.Reeves, C.V.The Kalahari, Central Southern Africa: a Case History of Regional and Magnetic Exploration.Unknown, P. 450. (abstract.).BotswanaGeophysics, Prospecting
DS1975-0167
1975
Reeves, C.V.Reeves, C.V., Hutchins, D.G.Crustal Structures in Central Southern AfricaNature., Vol. 254, No. 5498 MARCH 27TH. , PP. 408-410.South Africa, BotswanaGeophysics, Gravity, Geotectonics
DS1975-0389
1976
Reeves, C.V.Reeves, C.V.Gravity Studies in Botswana and Their Contribution to Regional Geophysics in Southern Africa.Leeds: Ph.d. Thesis, University Leeds, 143P.BotswanaRegional Tectonics, Kimberley
DS1975-0390
1976
Reeves, C.V.Reeves, C.V., Hutchins, D.G.The National Gravity Survey of Botswana 1972-1973Botswana Geological Survey Bulletin., No. 5, 44P. MAP 1:2, 000, 000.BotswanaGeophysics, Regional Tectonics
DS1975-0503
1977
Reeves, C.V.Fairhead, J.D., Reeves, C.V.Teleseimic Delay Times, Bouguer Anomalies and Inferred Thickness of the African Lithosphere.Earth Plan. Sci. Letters, Vol. 36, No. 1, PP. 63-76.Botswana, South AfricaGeophysics
DS1975-0602
1977
Reeves, C.V.Reeves, C.V.The Delineation of Crustal Provinces in Southern Africa From a Compilation of Gravity Data.Leeds University Research Institute of African Geology Annual Report, No. 20, PP. 36-41.BotswanaGeophysics, Regional Tectonics
DS1975-0603
1977
Reeves, C.V.Reford, M.S., Reeves, C.V.Reconnaissance Aeromagnetic Survey of BotswanaTerra Surveys Contract Report., (UNPUBL.)BotswanaGeophysics, Tectonics
DS1975-0847
1978
Reeves, C.V.Reeves, C.V.The Gravity Survey of Ngami land 1970 to 1971Botswana Geological Survey, Bulletin. No. 11. 84P. MAP 1: 500, 000BotswanaGeophysics
DS1975-0848
1978
Reeves, C.V.Reeves, C.V.Interpretation of the Reconnaissance Aeromagnetic Survey Ofbotswana.Botswana Geological Survey, REPORT, 199P.BotswanaGeophysics, Tectonics
DS1975-0849
1978
Reeves, C.V.Reeves, C.V.Reconnaissance Aeromagnetic Survey of Botswana 1975-1977. Final Interpretation Report.Botswana Geological Survey, PP. 1-199.BotswanaRegional Tectonics, Geophysics
DS1975-0850
1978
Reeves, C.V.Reeves, C.V.A Failed Gondwana Spreading Axis in Southern AfricaNature., Vol. 273, No. 5657 MAY 4TH. , PP. 222-223.South Africa, BotswanaGeotectonics
DS1975-1177
1979
Reeves, C.V.Paterson, N.R., Reford, M.S., Reeves, C.V.The Reconnaissance Aeromagnetic Survey of Botswana. Some Novel Techniques of Survey Execution, Dat a Compilation and Interpretation.Botswana Geological Survey, Bulletin. No. 22, PP. 31-66.BotswanaGeophysics, Tectonics
DS1975-1197
1979
Reeves, C.V.Reeves, C.V.The Reconnaissance Aeromagnetic Survey of Botswana. Ii. Its contribution to the Geology of the Kalahari.Botswana Geological Survey, Bulletin. No. 22, PP. 67-92.BotswanaRegional Tectonics, Geophysics
DS1980-0179
1980
Reeves, C.V.Hutchins, D.G., Reeves, C.V.Reginal Geophysical Exploration of the Kalahari in BotswanaTectonophysics, Vol. 69, PP. 201-220.BotswanaGeophysics, Airborne Magnetics, Gravity
DS1980-0180
1980
Reeves, C.V.Hutchins, D.G., Reeves, C.V.Regional Geophysical Exploration of the Kalahari in BotswanaTectonophysics, Vol. 69, PP. 201-220.GlobalTectonics, Geophysics
DS1982-0516
1982
Reeves, C.V.Reeves, C.V., Hutchins, D.G.A Progress Report on the Geophysical Exploration of the Kalahari in Botswana.Tectonophysics, Vol. 20, No. 2-3, PP. 209-224.BotswanaKimberlite, Geophysics, Tectonics
DS1988-0568
1988
Reeves, C.V.Reeves, C.V., Misener, D.J.New sedimentary basins in continental Africa from gravity and aeromagnetic surveyingEuropean Association of Exploration Geophysicists, abstract volume, 50th, p. 177 abstract onlyAfricaBlank
DS1996-1400
1996
Reeves, C.V.Tarlowski, C., McEwin, A.J., Reeves, C.V., Barton, C.E.Dewarping the composite aeromagnetic anomaly map of Australia using controltraverses and base stationsGeophysics, Vol. 61, No. 3, May-June pp. 696-705AustraliaGeophysics -aeomagnetics, Composite anomaly map
DS1998-0361
1998
Reeves, C.V.Doucoure, C.M., De Wit, M.J., Reeves, C.V.Towards a gravity map of Gondwana #1Journal of African Earth Sciences, Vol. 27, 1A, p. 62. AbstractGondwanaGeophysics - gravity
DS1998-1221
1998
Reeves, C.V.Reeves, C.V.Aeromagnetic and gravity features of continental Gondwana and their relation to continental break up...Journal of African Earth Sciences, Vol. 27, 1A, p. 153-5. AbstractGondwanaGeophysics - aeromagnetics, gravity
DS1998-1222
1998
Reeves, C.V.Reeves, C.V., De Wit, M.J.Gondwana re-assembly by retracing the transforms of the Indian OceanJournal of African Earth Sciences, Vol. 27, 1A, p. 156-7. AbstractGondwanaTectonics
DS1998-1275
1998
Reeves, C.V.Sahu, B.K., Reeves, C.V.Continental scale geophysical anomaly patterns: implications for Gondwanare-assembly.Journal of African Earth Sciences, Vol. 27, 1A, p. 165. AbstractGondwanaGeophysics
DS1998-1612
1998
Reeves, C.V.Yardimicilar, C., Reeves, C.V.Evidence from aeromagnetic anomalies for the pre-drift fit of Madagascar against East Africa.Journal of African Earth Sciences, Vol. 27, 1A, p. 215. AbstractMadagascarGeophysics - aeromagnetics, Tectonics - Gondwana
DS1999-0588
1999
Reeves, C.V.Reeves, C.V.Aeromagnetic and gravity features of Gondwana -relation to continental break up: more pieces, less puzzle.Journal of African Earth Sciences, Vol. 28, No. 1, pp. 263-77.GlobalGeophysics - magnetics, gravity
DS2000-0244
2000
Reeves, C.V.Doucoure, C.M., De Wit, M.J., Reeves, C.V.Towards a gravity map of Gondwana #2Journal of African Earth Sciences, Vol.31, No.1, July, pp.195-204.GondwanaGeophysics - gravity, Map
DS2000-0809
2000
Reeves, C.V.Reeves, C.V., De Wit, M.J.Making ends meet in Gondwana: retracing the transforms of the Indian Ocean and reconnecting continental shear zones.Terra Nova, Vol. 12, pp. 272-280.Gondwana, Indian OceanTectonics, transcontinental
DS2002-1323
2002
Reeves, C.V.Reeves, C.V., Sahu, B.K., De Wit, M.A re-examination of the paleo position of Africa's eastern neighbours in GondwanaJournal of African Earth Sciences, Vol.34, No.3-4,April-May pp. 101-8.Africa, GondwanaTectonics
DS200412-1645
2000
Reeves, C.V.Reeves, C.V., De Wit, M.J.Making ends meet in Gondwana: retracing the transforms of the Indian Ocean and reconnecting continental shear zones.Terra Nova, Vol. 12, pp. 272-280.Gondwana, Indian OceanTectonics, transcontinental
DS200412-1646
2004
Reeves, C.V.Reeves, C.V., De Wit, M.J., Sahu, B.K.Tight assembly of Gondwana exposes Phanerozoic shears in Africa as global tectonic players.Gondwana Research, Vol. 7, 1, pp. 7-20.AfricaTectonics
DS1993-1290
1993
Reeves, D.Reeves, D.Alluvial diamond mining and recovery operation at Argyle Diamond Mines Pty.Ltd.Australia Min. Met. Mawby Memorial Volume, Mon. 19, pp. 1453-1457.AustraliaMining, Deposit -Argyle
DS1987-0508
1987
Reeves, K.D.Nelson, D.O., Nelson, K.L., Reeves, K.D., Mattison, G.D.Geochemistry of Tertiary alkaline rocks of the Eastern Trans Pecosmagmatic province, TexasContributions to Mineralogy and Petrology, Vol. 97, No. 1, pp. 72-92GlobalAlkaline rocks
DS1989-1089
1989
Reeves, T.J.Napier-Munn, T.J., Reeves, T.J., Hansen, J.O.The monitoring of medium rheology in dense medium cyclone plantsAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin Proceedings Vol, Vol. 294, No. 3, May pp. 85-94AustraliaMineral processing, Heavy minerals
DS1984-0244
1984
Reeves-Smith, G.J.Drury, S.A., Harris, N.B.W., Holt, R.W., Reeves-Smith, G.J.Precambrian Tectonics and Crustal Evolution in South IndiaJournal of GEOLOGY, Vol. 92, PP. 3-20.IndiaGeotectonics
DS1997-0948
1997
Reezko, B.F.F.Reezko, B.F.F., Antoine, L.A.G., Eriksson, P.G.Three dimensional computer assisted basin modelling to generate exploration target areas: an example Archean.Mineralium Deposita, Vol. 32, No. 4, pp. 392-400South AfricaTransvaal Supergroup, Archean early Proterozoic, Basin, basement relief, gravity data, Datamine
DS201312-0738
2014
Refayee, H.A.Refayee, H.A., Yang, B.B., Liu, K.H., Gao, S.S.Mantle flow and lithosphere asthenosphere coupling beneath the southwestern edge of the North American craton: constraints from shear wave splitting measurements.Earth and Planetary Science Letters, Vol. 402, pp. 209-220.CanadaAnisotropy
DS1975-0603
1977
Reford, M.S.Reford, M.S., Reeves, C.V.Reconnaissance Aeromagnetic Survey of BotswanaTerra Surveys Contract Report., (UNPUBL.)BotswanaGeophysics, Tectonics
DS1975-1177
1979
Reford, M.S.Paterson, N.R., Reford, M.S., Reeves, C.V.The Reconnaissance Aeromagnetic Survey of Botswana. Some Novel Techniques of Survey Execution, Dat a Compilation and Interpretation.Botswana Geological Survey, Bulletin. No. 22, PP. 31-66.BotswanaGeophysics, Tectonics
DS1986-0363
1986
Reford, M.S.Hinze, W.J., Kane, M.F., O'Hara, N.W., Reford, M.S., Tanner, J., WeberThe utility of regional gravity and magnetic anomaly mapsSociety of Exploration Geophysicists, Special Volume, 400pUnited States, CanadaGeophysics
DS200812-0944
2008
Reford, S.W.Reford, S.W., La Prairie, L.L.Exploring for metals and diamonds at Darnley Bay. NT.Northwest Territories Geoscience Office, p. 51. abstractCanada, NunavutBrief overview - Darnley Bay
DS201012-0616
2010
Reford, S.W.Reford, S.W.Exploring for metals and diamonds at Darnley Bay, NT - a reality in 2010.38th. Geoscience Forum Northwest Territories, Abstract pp.120-121.Canada, NunavutGeophysics - geochemistry
DS201112-0111
2011
Reford, S.W.Brin, L.E., Pearson, D.G., Riches, A.J.V., Miskovic, A., Kjarsgaard, B.A., Kienlen, B., Reford, S.W.Evaluating the northerly extent of the Slave Craton in the Canadian Arctic.Yellowknife Geoscience Forum Abstracts for 2011, Poster abstract p. 95.Canada, Northwest Territories, Nunavut, Victoria Island, Parry PeninsulaKimberlite borne - xenoliths -
DS1996-0180
1996
Refson, K.Brodholt. J., Patel, A., Refson, K.An ab initio study of the compressional behavior of forsteriteAmerican Mineralogist, Vol. 81, pp. 257-60.MantleMineralogy
DS2001-0535
2001
Refson, K.Jephcoat, A., Refson, K.Core beliefs. Iron in inner coreNature, Vol. 413, Sept. 6, pp. 27-28.MantleInner core, geochemistry
DS202012-2204
2020
Refus, K.S.Bassoo, R., Refus, K.S.Finders Keepers: Crater of Diamonds Gems & Gemology, Vol. 56, 2, summer pp. 311-314. United States, Arkansasdeposit - Crater of diamonds

Abstract: There’s only one place on earth where the general public can prospect for diamonds directly from a primary kimberlite pipe: Crater of Diamonds State Park. This park is nestled among the pines, 100 miles off the interstate near the town of Murfreesboro, Arkansas. It boasts a network of scenic walking trails, picnic sites, and campsites. At its Diamond Discovery Center, visitors can learn about the local geology. Staff are also on hand to identify any minerals that are taken home, per their "finders, keepers" policy. The park is an ideal spot for a field trip. The state also hosts many other unusual igneous rocks, including carbonatite, lamprophyre, and lamproite. With this in mind, our university petrology class piled into a van to visit Arkansas and learn about mantle-derived magmas and associated volcanism. As a side quest, we wanted to try prospecting.
DS1982-0295
1982
Regan, R.D.Jain, B.K., Regan, R.D.Integration of Satellite and Conventional Geophysical Dat a with tectonics and Structural Information Over the African Continent.Geoexploration., Vol. 20, No. 3-4, PP. 233-258.Africa, West Africa, Central Africa, East Africa, Southwest AfricaStructure, Tectonics, Remote Sensing
DS1989-1483
1989
Regan, R.D.Taylor, P.T., Schnetzler, C.C., Regan, R.D.Satellite magnetic data: how useful in exploration?Geophysics: the Leading Edge of Exploration, Vol. 8, No. 11, NOvember pp. 26-28GlobalGeophysics, Landsat magnetics
DS201012-0104
2010
Regan, S.Chiarenzelli, J., Lupulescu, M., Cousens, B., Thern, E., Coffin, L., Regan, S.Enriched Grenvillian lithospheric mantle as a consequence of long lived subduction beneath Laurentia.Geology, Vol. 38, 2, pp. 151-154.Canada, QuebecGeochronology, subduction
DS2003-1150
2003
Regard, V.Regard, V., Faccenna, C., Martinod, J., Bellier, O., Thomas, J-C.From subduction to collision: control of deep processes on the evolution of convergentJournal of Geophysical Research, Vol. 108, B4. 10.1029/2002JB001943MantleSubduction, Tectonics
DS200412-1647
2003
Regard, V.Regard, V., Faccenna, C., Martinod, J., Bellier, O., Thomas, J-C.From subduction to collision: control of deep processes on the evolution of convergent plate boundary.Journal of Geophysical Research, Vol. 108, B4. 10.1029/2002 JB001943MantleSubduction Tectonics
DS2002-0810
2002
Rege, S.Karmalkar, N.R., Rege, S.Cryptic metasomatism in the upper mantle beneath Kutch: evidence from spinel lherzolite xenoliths.Current Science, Vol.82,9,pp.1157-64.MantleMetasomatism
DS2003-1151
2003
Rege, S.Rege, S., Davies, R.M., Griffin, W.L., Jackson, S., O'Reilly, S.Y.Trace element analysis of diamonds by LAM ICPMS: preliminary results8 Ikc Www.venuewest.com/8ikc/program.htm, Session 3, AbstractRussia, Siberia, Australia, Brazil, Northwest TerritoriesDiamonds - database 115, Geochemistry
DS200412-1648
2003
Rege, S.Rege, S., Davies, R.M., Griffin, W.L., Jackson, S., O'Reilly, S.Y.Trace element analysis of diamonds by LAM ICPMS: preliminary results.8 IKC Program, Session 3, AbstractRussia, Siberia, AustraliaDiamonds - database 115 Geochemistry
DS200512-0496
2005
Rege, S.Karmalkar, N.R., Rege, S., Griffin, W.L., O'Reilly, S.Y.Alkaline magmatism from Kutch, NW India: implications for plume lithosphere interaction.Lithos, Vol. 81, 1-4, April pp. 101-119.IndiaDeccan Volcanic Province, Reunion plume, metasomatism
DS200612-0501
2006
Rege, S.Griffin, W.L., Rege, S., O'Reilly, S.Y., Jackson, S.E., Pearson, N.J., Zedgenizov, D., Kurat, G.Trace element patterns of diamond: toward a unified genetic model.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 218. abstract only.TechnologyDiamond genesis geochemistry
DS200612-1147
2006
Rege, S.Rege, S.Trace elements are a girl's best friend: how diamonds form.GEMOC Annual Report, 2005, p. 26-27.MantleTrace element analyses LAM-ICPMS
DS200812-0945
2008
Rege, S.Rege, S., Griffin, W.L., Kurat, G., Jackson, S.E., Pearson, N.J., OReilly, S.Y.Trace element geochemistry of diamondite: crystallization of diamond from kimberlite carbonatite melts.Lithos, Vol. 106, 1-2, pp. 39-54.TechnologyDiamondite
DS201012-0617
2010
Rege, S.Rege, S., Griffin, W.L., Pearson, A.J., Araujo, D., Zedgenizov, D., O'Reilly, S.Y.Trace element patterns of fibrous and monocrystalline diamonds: insights into mantle fluids.Lithos, Vol. 118, pp. 313-337.TechnologyDiamond genesis, morphology
DS201112-0849
2006
Rege, S.Rege, S.Trace element geochemistry of diamond.Thesis: Macquarie University Phd. , Thesis: note availability based on request to author
DS1996-1169
1996
Regelous, M.Regelous, M., Collerson, K.D.Sm neodymium systematics of Early Archean rocks and implications for crust mantleevolution.Geochimica et Cosmochimica Acta ., Vol. 60, No. 18, Sept. pp. 3513-20.Labrador, MantleGeochronology, North Atlantic Craton
DS200812-1097
2008
Regenauer Lieb, K.Sommer, H., Regenauer Lieb, K., Hauzenberger, C., Gasharova, B.Rapid uplift of the Jwaneng kimberlite, south Botswana: caused by mantle metasomatism and documented by OH diffusion profiles in garnet from eclogitic xenoliths.Goldschmidt Conference 2008, Abstract p.A882.Africa, BotswanaDeposit - Jwaneng
DS200812-1199
2008
Regenauer Lieb, K.Van der Lee, S., Regenauer Lieb, K., Yuen, D.A.The role of water in connecting past and future episodes of subduction.Earth and Planetary Science Letters, Vol. 273, 1-2, Aug. 30, pp. 15-27.MantleSubduction
DS200812-1098
2008
Regenauerlieb, K.Sommer, H., Regenauerlieb, K., Gasharova, B., Siret, D.Grain boundaries: a possible water reservoir in the Earth's mantle?Mineralogy and Petrology, Vol. 94, 1-2, pp. 1-8.MantleWater
DS200812-1139
2008
RegenauerLieb, K.Summer, H., RegenauerLieb, K., Gasharova, B., Siret, D.Grain boundaries: a possible water reservoir in the Earth's mantle?Mineralogy and Petrology, in press available, 8p.MantleWater
DS200912-0560
2008
Regenauerlieb, K.OzBench, M., Regenauerlieb, K., Stegman, D.R., Morra, G., Farrington, R., Hale, A., May, D.A., Freeman, J.A model comparison study of large scale mantle lithosphere dynamics driven by subduction.Physics of the Earth and Planetary Interiors, Vol. 171, 1-4, pp. 224-234.MantleTectonics
DS2000-0810
2000
Regenauer-Lieb, K.Regenauer-Lieb, K., Yuen, D.A.Fast mechanisms for the formation of new plate boundariesTectonophysics, Vol.322, No.1-2, July10, pp.53-68.MantleTectonics, Plates
DS200612-0952
2005
Regenauer-Lieb, K.Muhlhaus, H-B., Regenauer-Lieb, K.Towards a self consistent plate mantle model that includes elasticity: simple benchmarks and application to basic modes of convection.Geophysical Journal International, Vol. 163, 2, Nov. pp. 788-800.MantleGeophysics - convection
DS200712-0444
2007
Regenauer-Lieb, K.Hobbs, B., Regenauer-Lieb, K., Ord, A.Thermodynamics of folding in the middle to lower crust.Geology, Vol. 35, 2, pp. 175-176.MantleTectonics
DS200812-1200
2008
Regenauer-Lieb, K.Van der Lee, S., Regenauer-Lieb, K., Yuen, D.A.The role of water in connecting past and future episodes of subduction.Earth and Planetary Science Letters, Vol. 273, pp. 15-27.MantleSubduction - water
DS200912-0595
2009
Regenauer-Lieb, K.Potgeiter, J., Sommer, H., Regenauer-Lieb, K., Gasharova, B., Purchase, M.OH and CO2 diffusion profiles in garnets from eclogite xenoliths from the Rovic diamond mine, South Africa. ( Unesco IGCP 557)Goldschmidt Conference 2009, p. A1046 Abstract.Africa, South AfricaDeposit - Rovic
DS200912-0596
2008
Regenauer-Lieb, K.Potgeter, J., Sommer, H., Regenauer-Lieb, K., Gasharova, B.Oh and CO2 diffusion profiles in garnets from eclogitic xenoliths from the Victor mine, South Africa.American Geological Union, Fall meeting Dec. 15-19, Eos Trans. Vol. 89, no. 53, meeting supplement, 1p. abstractAfrica, South AfricaDeposit - Roberts Victor
DS200912-0603
2009
Regenauer-Lieb, K.Purchase, M., Sommer, H., Regenauer-Lieb, K., Gasharova, B., Potgeiter, J.OH partitioning coefficient between garnets and melt inclusions in lherzolite xenoliths from the Kimberley diamond mine, South Africa.Goldschmidt Conference 2009, p. A1059 Abstract.Africa, South AfricaDeposit - Kimberley
DS200912-0622
2008
Regenauer-Lieb, K.Regenauer-Lieb, K., Sommer, H., Gaede, H., Gaede, O.Weertman cracks and the fast extraction of diamonds from the Earth's mantle.American Geological Union, Fall meeting Dec. 15-19, Eos Trans. Vol. 89, no. 53, meeting supplement, 1p. abstractAfrica, BotswanaDeposit - Jwaneng
DS200912-0715
2009
Regenauer-Lieb, K.Sommer, H., Regenauer-Lieb, K., Gaede, O.Weertman cracks and the near sonic extraction of diamonds from the Earth's mantle.Goldschmidt Conference 2009, p. A1249 Abstract.Africa, BotswanaDeposit - Jwaneng
DS201012-0637
2010
Regenauer-Lieb, K.Rosenbaum, G., Regenauer-Lieb, K., Weinberg, R.F.Interaction between mantle and crustal detachments: a nonlinear system controlling lithospheric extension.Journal of Geophysical Research, Vol. 115, B 11, B11412MantleGeodynamics
DS201112-0505
2011
Regenauer-Lieb, K.Karrech, A., Regenauer-Lieb, K., Poulet, T.Continuum damage mechanics for the lithosphere.Journal of Geophysical Research, Vol, 116, B4, B04205.MantleTectonics
DS201112-0816
2011
Regenauer-Lieb, K.Potgeiter, J., Sommer, H., Regenauer-Lieb, K., Jung, H., Gasharova, B.The formation of microdiamonds in cracks caused by C-O-H rich fluid under medium to low pressure conditions.Goldschmidt Conference 2011, abstract p.1662.Africa, South AfricaVictor
DS201112-0836
2011
Regenauer-Lieb, K.Purchase, M., Sommer, H., Regenauer-Lieb, K., Jung, H., Gasharova, B.Coexistent aqueous fluid phase and melt in lherzolites from Bultfontein, South Africa.Goldschmidt Conference 2011, abstract p.1675.Africa, South AfricaDeposit - Bultfontein
DS201112-0986
2011
Regenauer-Lieb, K.Sommer, H., Regenauer-Lieb, K., Gaede, O., Jung, H., Gasharova, B.WEERTMAN cracks: a possible mechanism for near sonic speed diamond extraction from the Earth's mantle.Goldschmidt Conference 2011, abstract p.1908.MantleTransport for diamond bearing kimberlite melts
DS201212-0692
2012
Regenauer-Lieb, K.Sommer, H., Regenauer-Lieb, K., Gasharova, B., Jung, H.The formation of volcanic centers at the Colorado Plateau as a result of the passage of aqueous fluid through the oceanic lithospher and the subcontinental mantle" new implications for the planetary water cycle in the western United States.Journal of Geodynamics, Vol. 61, Oct. pp. 154-171.United States, Colorado PlateauVolcanism
DS200712-1015
2007
Regenauer-Lieb, K.R.Sommer, H., Regenauer-Lieb, K.R., Hauzenberger, C.Diamonds, xenoliths and kimberlites: a window in the Earth's mantle. UNESCO IGCP 557.Plates, Plumes, and Paradigms, 1p. abstract p. A954.MantleE and P type diamonds
DS202106-0940
2021
Regenauer-Lieb. K.Halim, A.Y., Kelloway, S.J., Marjo, C., Regenauer-Lieb. K.A Hylogger-Itrax core-scanner comparison for multi-scale high resolution petrophysical characterization workflow. * not specific to diamondsApplied Chemistry, in press available, 18p. PdfGlobalHylogger

Abstract: Recent advances in core scanning technologies allow for fast and non-destructive chemical and mineral profiling of rock samples for mineral services and oil and gas exploration. The aim of these automatic core scan methods is to obtain valuable information for profiling drill core cuttings with minimum sample preparation at relatively high speed. In the last decade, a core logging system using an automated infrared-based hyperspectral line-profiling system, Hylogger, has progressed to become an effective standard for the Australian mineral exploration industry. Its results are used to rapidly obtain mineralogical information allowing the characterisation of different geological formations in near real-time. The interpretation of Hylogger data can be challenging for certain complex mineral mixtures. Here we solve this issue by augmenting the Hylogger interpretation with elemental analysis using the Itrax core scanner equipped with an X-ray fluorescence (XRF) spectrometer. The Itrax core scanner produces high-resolution elemental data of major, minor and trace elements in one dimension. We analyse and compare the Hylogger and Itrax data, with each dataset independently cross-checked using X-ray diffraction (XRD) and thin-section petrology and propose a workflow harvesting the mutual strengths of each method. The recommended workflow consists of rapid screening using Hylogger and XRF analysis, providing new insights into the mineralogy based on comparative multiscale element-mineral analysis. The workflow is tested on four different types of volcanic rock samples, where infrared spectra of individual minerals overlap. We tested tuffaceous ash, basaltic, dolerite, and basaltic-andesitic rocks. Our study shows that embedding Itrax core scanner data into the workflow provides a solution to the challenges of interpreting Hylogger data in complex mineral samples. The proposed workflow provides a total system for multiscale, high-resolution petrophysical analyses and rock property modelling.
DS201908-1802
2019
Regier, M.Pearson, D.G., Stachel, T., Li, L., Li, K., Stern, R., Howell, D., Regier, M.Diamonds and their inclusions: a unique record of plate tectonic recycling. AOCwww.minsocam.org/ MSA/Centennial/ MSA_Centennial _Symposium.html The next 100 years of mineral science, June 20-21, p. 22. AbstractMantlediamond inclusions

Abstract: Much of the temporal record of Earth’s evolution, including its trace of plate tectonics, is blurred due to the dynamic nature of the crust-mantle system. While zircon provides the highest fidelity crustal record, diamond takes over in the mantle as the go-to mineral, capable of retaining critical information for a variety of geochemical proxies, over billion year timescales. Here we use diamond and its inclusions to tell the story of the recycling of C, N, O, H and B from the crust to various depths in Earth’s mantle. In this story, altered oceanic crust (AOC) and lithospheric mantle will play a prominent role. The carbon isotope record of diamond has long been thought to reflect the mixing of primitive mantle carbon with carbon recycled from isotopically light organic material originating from the crust. A major difficulty has been reconciling this view with the highly varied nitrogen and carbon isotope signatures in diamonds of eclogitic paragenesis, which cannot be interpreted by the same mechanism. Recent work on AOC of igneous origin (Li et al., EPSL in press) shows how isotopically varied carbon and nitrogen can be subducted to great depth and retained in spatial juxtaposition with the mafic silicate component of AOC to form the complex C-N isotope systematics observed in diamonds and the varied O isotope compositions of their inclusions. In this model a large portion of the 13C depleted carbon originated from biogenic carbonate within the AOC rather than from overlying sediments. Metamorphosed and partially devolatilized AOC will have very variable C/N ratios and highly variable nitrogen isotopes, explaining why simple two component mixing between organic matter and convecting upper mantle cannot explain the complexity of C-N isotope systematics in diamonds. Igneous AOC and its underlying altered mantle are considerably more efficient than subducted sediment at retaining their volatile inventory when recycled to transition zone and even lower mantle depths. Hence, this combination of mixing between AOC-derived volatiles and those from the convecting mantle produces the isotopic fingerprints of superdeep diamonds and their inclusions. These amazing diamonds, some worth millions of dollars, can contain pristine ultra-high pressure mineral phases never before seen in terrestrial samples. The first hydrous ringwoodite found in Earth provides evidence in support of a locally water-saturated transition zone that may result from altered oceanic lithospheric mantle foundering at that depth in the mantle. The O isotope composition of deep asthenosphere and transition zone phases document clearly crustal precursors that have interacted with the hydrosphere before residing hundreds of km deep within the Earth. Finally, spectacular blue diamonds contain boron, an element of strong crustal affinities, transported into the deep Earth along with crustal carbon, by the plate tectonic conveyor system. Diamond - such a simple mineral - and its inclusions, will continue to provide a unique, brightly illuminating light into the darkest recesses of Earth’s mantle for many years to come.
DS201908-1825
2019
Regier, M.Wenz, M.D., Jacobsen, S.D., Zhang, D., Regier, M., Bausch, H.J., Dera, P.K., Rivers, M., Eng, P., Shirey, S.B., Pearson, D.G.Fast identification of mineral inclusions in diamond at GSECARS using synchrotron X-ray microtomography, radiography and diffraction.Journal of Synchrotron Radiation, Vol. 26, doi.org/10.1107 /S1600577519006854 6p. PdfMantlediamond inclusions

Abstract: Mineral inclusions in natural diamond are widely studied for the insight that they provide into the geochemistry and dynamics of the Earth's interior. A major challenge in achieving thorough yet high rates of analysis of mineral inclusions in diamond derives from the micrometre-scale of most inclusions, often requiring synchrotron radiation sources for diffraction. Centering microinclusions for diffraction with a highly focused synchrotron beam cannot be achieved optically because of the very high index of refraction of diamond. A fast, high-throughput method for identification of micromineral inclusions in diamond has been developed at the GeoSoilEnviro Center for Advanced Radiation Sources (GSECARS), Advanced Photon Source, Argonne National Laboratory, USA. Diamonds and their inclusions are imaged using synchrotron 3D computed X-ray microtomography on beamline 13-BM-D of GSECARS. The location of every inclusion is then pinpointed onto the coordinate system of the six-circle goniometer of the single-crystal diffractometer on beamline 13-BM-C. Because the bending magnet branch 13-BM is divided and delivered into 13-BM-C and 13-BM-D stations simultaneously, numerous diamonds can be examined during coordinated runs. The fast, high-throughput capability of the methodology is demonstrated by collecting 3D diffraction data on 53 diamond inclusions from Juína, Brazil, within a total of about 72 h of beam time.
DS202012-2243
2020
Regier, M.Regier, M. Distinct diamond forming mechanisms in the lithosphere, asthenosphere, and lower mantle.https://www.youtube. com/channel/ UCcZvayDnqD DazIHAh1Otreg, Nov 3 ppt presenation ( see also her paper in Nature previously listed in Newsletter)Mantlediamond genesis. Cratons

Abstract: November 2020 Vancouver Kimberlite Cluster presentation. 'Superdeep' diamonds from the sublithospheric mantle (greater than 250 km in depth) comprise some of the most highly-priced samples in kimberlitic diamond deposits. These superdeep diamonds are distinguished from their more common lithospheric diamonds cousins by their large sizes, highly resorbed morphologies, and characteristic inclusion assemblages. Despite these defining characteristics, our understanding of superdeep diamond formation remains limited. How exactly does diamond formation differ between the upper and lower mantle? In this presentation, I will discuss how stable isotopic analyses of lithospheric to lower mantle diamonds can elucidate the various diamond forming mechanisms that operate at these depths. I will show evidence for diamond-forming carbonate-rich magmas in the transition zone and will illustrate how the final dehydration of slabs may remobilize carbon trapped in metallic phases in the lower mantle.
DS201809-2079
2018
Regier, M.E.Regier, M.E., Pearson, D.G., Stachel, T., Stern, R.A., Harris, J.W.Oxygen isotopes in Kankan super deep diamond inclusions reveal variable slab mantle interaction.Goldschmidt Conference, 1p. AbstractAfrica, South Africa, Guinea, South America, Brazildeposit - Kankan, Jagersfontein, Juina

Abstract: Inclusions in super-deep diamonds provide a unique window to the sublithospheric mantle (e.g. [1-4]). Here we present oxygen isotopes for Kankan majoritic garnet and former bridgmanite inclusions. The clustering of Kankan majorites around a ?18O of +9‰ is nearly identical to those reported from Jagersfontein [1]. This elevated and nearly constant ?18O signal indicates homogenization of partial melts from the uppermost part of altered basaltic slabs. Conversely, ?18O values in Juina majorites are highly variable [2] due to crystallization from small, discrete melt pockets in a heterogeneous eclogitic source. While all these majorites have eclogitic/pyroxenitic Cr2O3 and CaO contents, charge-balance for Si[VI] is achieved very differently, with Jagersfontein [3], Kankan [4], and Juina [2] majorites transitioning from eclogitic Na[VIII]Si[VI] to peridotitic-pyroxenitic [5] Mg[VI]Si[VI] substitutions. We interpret this shift as the result of homogenized eclogitic partial melts infiltrating and reacting with adjacent pyrolitic mantle at Kankan and Jagersfontein. Increases in Mg# and Cr2O3 with reductions in ?18O support this reaction. This model is in agreement with recent experiments in which majorites and diamonds form from a reaction of slab-derived carbonatite with reduced pyrolite at 300-700 km depth [6]. The Kankan diamonds also provide an opportunity to establish the chemical environment of the lower mantle. Four inclusions of MgSiO3, inferred to be former bridgmanite [4], provide the first-measured ?18O values for lower mantle samples. These values suggest derivation from primitive mantle, or unaltered subducted oceanic lithospheric mantle. The Kankan super-deep inclusions thus provide a cross-section of deep mantle that highlights slab-pyrolite reactions in the asthenosphere and primitive compositions in the lower mantle.
DS201812-2773
2018
Regier, M.E.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.
DS201812-2870
2018
Regier, M.E.Regier, M.E., Pearson, D.G., Stachel, T., Stern, R.A., Harris, J.Tracing the formation and abundance of superdeep diamonds.2018 Yellowknife Geoscience Forum , p. 63. abstractAfrica, Guineadeposit - Kankan

Abstract: Super-deep diamonds from the transition zone and lower mantle are valuable targets for mining, as they are often large, gem-quality1 or ultra-valuable type IIb stones2. Hence, in mine prospects, it may become important to determine the various populations of sub-lithospheric diamonds. Unambiguously identifying a diamond’s depth of formation is difficult as some minerals can be indicative of various depth regimes (e.g., ferropericlase, Ca-walstromite, enstatite, clinopyroxene, coesite). Here, we use the oxygen isotope compositions of inclusions in Kankan diamonds from Guinea to distinguish between the various diamond-forming processes that happen at lithospheric, asthenospheric to transition zone, and lower mantle depths. In this way, we hope to establish a process by which isotope geochemistry can better constrain the populations of superdeep diamonds in kimberlites, and can assist in estimating a pipe’s propensity for large, valuable stones. Oxygen isotopic analysis by secondary ion mass spectrometry (SIMS) is a high-precision technique that can track hydrothermal alteration that occurred at or close below the ocean floor. Our analyses of inclusions from Kankan diamonds demonstrate that garnets with 3-3.03 Si cations (pfu) have ?18O that are well-constrained within the normal values expected for peridotitic and eclogitic inclusions, but that garnets with ?3.04 Si cations (pfu) have consistently high ?18O (median: 10‰) that slightly decreases with increasing Cr2O3. We interpret this signal as the reaction between a melted carbonate-rich oceanic slab and normal convecting asthenosphere3. In contrast, retrogressed, or former, bridgmanite has ?18O values similar to primitive mantle, suggesting little involvement of slab melts. In contrast to the worldwide suite of lithospheric inclusions of eclogitic paragenesis (median ?18O of 7.03‰)4,5, diamonds derived from ~250 to 500 km have inclusions with consistent, extremely high oxygen isotopes (median: 9.32‰)6,7, due to the melting of extremely enriched carbonated oceanic crust. Diamonds from the lower mantle, however, have inclusions with primitive mantle oxygen isotopes, suggesting a different formation process. The clear distinction in inclusion ?18O between lithospheric, asthenospheric to transition zone, and lower mantle diamond populations is useful in informing the depth regime of a suite of stones, especially those with inclusions of ambiguous depths (e.g., clinopyroxene, coesite, Ca-walstromite, enstatite, ferropericlase, etc.). For instance, we are currently searching for exotic oxygen isotopes in ferropericlase that indicate asthenospheric diamond growth, rather than the primitive mantle values expected for lower mantle ferropericlase. In conclusion, oxygen isotopic analyses of diamond inclusions can identify various sublithsopheric diamond populations, and may benefit the assessment of a mine’s potential for large gem-quality, or type IIb diamonds.
DS201902-0310
2018
Regier, M.E.Regier, M.E., Miskovic, A., Ickert, R.B., Pearson, D.G., Stachel, T., Stern, R.A., Kopylova, M.An oxygen isotope test for the origin of Archean mantle rootsGeochemical Perspectives Letters, Vol. 9, pp. 6-10. 10.7185/geochemlet.1830Mantleperidotites

Abstract: The origin of the peridotites that form cratonic mantle roots is a central issue in understanding the history and survival of Earth’s oldest continents. A long-standing hypothesis holds that the unusual bulk compositions of some cratonic peridotites stem from their origin as subducted oceanic serpentinite, dehydrated during subduction to form rigid buoyant keels (Schulze, 1986; Canil and Lee, 2009). We present oxygen isotope data from 93 mantle peridotites from five different Archean cratons to evaluate their possible origin as serpentinites. Cratonic mantle peridotite shows remarkably uniform ?18O values, identical to modern MORB-source mantle, that do not vary with bulk rock Si-enrichment or Ca-depletion. These data clearly conflict with any model for cratonic lithosphere that invokes serpentinite as a protolith for cratonic peridotite, and place additional constraints on cratonic mantle origins. We posit that the uniform ?18O was produced by sub-arc and/or MOR depletion processes and that the Si-enriched nature of some samples is unlikely to be related to slab melt infiltration. Instead, we suggest a peridotitic source of Si-enrichment, derived from ascending mantle melts, or a water-fluxed depleted mantle. These variably Si-enriched, cratonic mantle protoliths were then collisionally compressed into the thick cratonic roots that have protected Earth’s oldest continental crust for over 2.5 Gyr.
DS202010-1872
2020
Regier, M.E.Regier, M.E., Pearson, D.G., Stachel, T., Luth, R.W., Stern, R.A., Harris, J.W.The lithospheric-to-lower-mantle carbon cycle recorded in superdeep diamonds. ( Kankan)Nature, Vol. 585, pp. 234-238. pdfAfrica, Guineadiamond inclusions

Abstract: The transport of carbon into Earth’s mantle is a critical pathway in Earth’s carbon cycle, affecting both the climate and the redox conditions of the surface and mantle. The largest unconstrained variables in this cycle are the depths to which carbon in sediments and altered oceanic crust can be subducted and the relative contributions of these reservoirs to the sequestration of carbon in the deep mantle1. Mineral inclusions in sublithospheric, or ‘superdeep’, diamonds (derived from depths greater than 250 kilometres) can be used to constrain these variables. Here we present oxygen isotope measurements of mineral inclusions within diamonds from Kankan, Guinea that are derived from depths extending from the lithosphere to the lower mantle (greater than 660 kilometres). These data, combined with the carbon and nitrogen isotope contents of the diamonds, indicate that carbonated igneous oceanic crust, not sediment, is the primary carbon-bearing reservoir in slabs subducted to deep-lithospheric and transition-zone depths (less than 660 kilometres). Within this depth regime, sublithospheric inclusions are distinctly enriched in 18O relative to eclogitic lithospheric inclusions derived from crustal protoliths. The increased 18O content of these sublithospheric inclusions results from their crystallization from melts of carbonate-rich subducted oceanic crust. In contrast, lower-mantle mineral inclusions and their host diamonds (deeper than 660 kilometres) have a narrow range of isotopic values that are typical of mantle that has experienced little or no crustal interaction. Because carbon is hosted in metals, rather than in diamond, in the reduced, volatile-poor lower mantle2, carbon must be mobilized and concentrated to form lower-mantle diamonds. Our data support a model in which the hydration of the uppermost lower mantle by subducted oceanic lithosphere destabilizes carbon-bearing metals to form diamond, without disturbing the ambient-mantle stable-isotope signatures. This transition from carbonate slab melting in the transition zone to slab dehydration in the lower mantle supports a lower-mantle barrier for carbon subduction.
DS1860-0132
1871
Regimental PressRegimental PressA Story of a Four Months Sojourn in the Diamond Fields of South Africa by an Officer of the Royal Engineers. Kimberley areaRangoon: Regimental Press, 85P.Africa, South Africa, Griqualand WestTravelogue
DS202004-0522
2020
Regis, D.Kellett, D.A., Pehrsson, S., Skipton, D., Regis, D., Camacho, A., Schneider, D., Berman, R.Thermochronological history of the Northern Canadian Shield. Nuna, Churchill Province, Trans-Hudson orogen, Thelon, RaePrecambrian Research, doi.org/10.1016/j.precamres.2020.105703 in press available 80p. PdfCanadageothermometry

Abstract: The northern Canadian Shield is comprised of multiple Archean cratons that were sutured by the late Paleoproterozoic to form the Canadian component of supercontinent Nuna. More than 2000 combined K-Ar and 40Ar/39Ar cooling ages from across the region reveal a stark contrast in upper and lower plate thermal responses to Nuna-forming events, with the Churchill Province in particular revealing near complete thermal reworking during the late Paleoproterozoic. We review the detailed cooling history for five regions that span the Churchill Province and Trans-Hudson orogen (THO): Thelon Tectonic Zone, South Rae, Reindeer Zone, South Hall Peninsula, and the Cape Smith Belt. The cooling patterns across Churchill Province are revealed in two >1500 km transects. At the plate scale, Churchill’s cooling history is dominated by THO accretionary and collisional events, during which it formed the upper plate. Cooling ages generally young from west to east across both southern and central Churchill, and latest cooling in the THO is 50 myr older in southernmost Churchill (Reindeer Zone) compared to eastern Churchill (Hall Peninsula), indicating diachronous thermal equilibration across 2000 km strike length of the THO. Churchill exhibits relatively high post-terminal THO cooling rates of ~4 °C/myr, which support other geological evidence for widespread rapid exhumation of the THO upper plate following terminal collision, potentially in response to lithospheric delamination.
DS202103-0402
2021
Regis, D.Regis, D., Pehrsson, S., Martel, E., Thiessen, E., Peterson, T., Kellett, D.Post - 1.9 Ga evolution of the south Rae craton ( Northwest Territories), Canada: a paleoproterozoic orogenic collapse system.Precambrian Research, Vol. 355, 106105, 29p. PdfCanada, Northwest Territoriessunduction

Abstract: The Trans-Hudson Orogen (THO), formed from the convergence between the Superior craton and the composite Churchill Upper Plate (CUP), is one of the best-preserved examples of a collisional orogen in the Paleoproterozoic. Similar to modern collision systems such as the Himalayan orogen, it is characterized by a composite upper plate in which terrane accretion established a continental plateau that was tectonically and magmatically active for >100 myr. Our study presents new petrological and geochronological data for four samples collected in three lithotectonic domains of the south Rae craton (one of the CUP terranes). The results presented here allow us to re-define the previously proposed extent of THO reworking in the CUP and afford the opportunity to study and compare the evolution of various fragments that illustrate differing levels of a collapsed plateau in the CUP hinterland. The new data indicate that the south Rae craton locally preserves evidence for burial at 1.855-1.84 Ga with peak metamorphic conditions at approximately 790 °C and 9.5-12.5 kbar followed by rapid cooling and decompression melting (P < 6 kbar) at ca. 1.835-1.826 Ga. These results, which provide important and so far missing Pressure-Temperature-time (P-T-t) constraints on the evolution of the south Rae craton in the Northwest Territories at Trans-Hudson time, coupled with existing regional geochronological and geochemical data, are used to propose an updated model for the post-1.9 Ga THO collision and extensional collapse. Our results reveal that: i) initial thickening in the upper plate started at Snowbird time (ca. 1.94 Ga), then continued via Sask collision (with high-grade metamorphism recorded in the south Rae craton, ca. 1.85 Ga), and ended with Superior collision (ca. 1.83 Ga); ii) the extent of the THO structural and metamorphic overprint in the SW CUP is much broader across strike than previously recognized, and iii) T-t data in the south Rae are indicative of relatively fast cooling rates (8-25 °C/Ma) compared to other known Precambrian orogens. We suggest that the Paleoproterozoic THO represents the first record of a major ‘modern-style’ orogenic plateau collapse in Earth’s history.
DS1991-1409
1991
Regis, E.Regis, E.Diamonds in the rough. Earth has been making diamonds since the dawn oftime. John Angus has been making them since the 1960's. He may have found a better wayDiscover, Vol. 12, No. 3, March pp. 66-71GlobalSynthetic diamonds, CVD.
DS1900-0796
1909
RegisterRegisterAnother Diamond Found at EchungaRegister., AUGUST 26TH.Australia, South AustraliaDiamond
DS1998-0120
1998
Regnoult, J.M.Bertil, D., Regnoult, J.M.Seismotectonics of MadagascarTectonophysics, Vol. 294, No. 1-2, Aug. 30, pp. 57-74.MadagascarGeophysics - seismics, Tectonics
DS201412-0728
2014
Rego, F.M.Rego, F.M., Cunha, L.M., Silveira, F.V., Borges, W.R.Caracterizacao geoleltrica de aluvioes diamantiferos no Rio Santo Inacio - Coromandel, M.G.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 4p. AbstractSouth America, Brazil, Minas GeraisCoromandel geophysics
DS1998-1223
1998
Regolith 98Regolith 98New approaches to an old continent.. third Australian regolith conferenceRegolith 98, May 2-9AustraliaConference - ad, Regoliths
DS1992-1265
1992
Regueiro, M.N.Regueiro, M.N., Monceau, P., Hodeau, J-L.Crushing C60 to diamond at room temperatureNature, Vol. 355, No. 6357, January 16, pp. 237-238GlobalExperimental petrology, Carbon
DS1993-0967
1993
Reguilon, R.Mangas, J., Perez-Torrado, F.J., Reguilon, R., Martin-Izard, A.Geological characteristics of alkaline rocks and carbonatites of Fuerteventura (Canary Islands, Spain) and their rare earth elements (REE) ore potential.Terra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 32.GlobalCarbonatite
DS201112-0160
2011
ReguirChakmouradian, A.R., Bohm, Coeslan, Mumin, Reguir, Demeny, Simonetti, Kressall, Martins, Kamenov, Creaser, LepekhinaPostorogenic carbonatites: more abundant than we realize and more important than given credit for.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.17-19.Canada, ManitobaCinder Lake, Eden Lake, Paint Lake
DS201112-0161
2011
ReguirChakmouradian, A.R., Bohm, Coeslan, Mumin, Reguir, Demeny, Simonetti, Kressall, Martins, Kamenov, Creaser, LepekhinaPostorogenic carbonatites: more abundant than we realize and more important than given credit for.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.17-19.Canada, ManitobaCinder Lake, Eden Lake, Paint Lake
DS200712-0882
2007
Reguir, E.Reguir, E., Halden, N., Chakmouradian, A., Yang, P., Zaitsev, A.N.Contrasting evolutionary trends in magnetite from carbonatites and alkaline silicate rocks.Plates, Plumes, and Paradigms, 1p. abstract p. A826.Africa, TanzaniaCarbonatite
DS200812-0946
2008
Reguir, E.Reguir, E., Chakhmouradian, A., Halden, N., Malkovets, V., Yang, P.Major and trace element compositional variation of phlogopite from kimberlites and carbonatites as a petrogenetic indicator.9IKC.com, 3p. extended abstractCanada, AfricaGeochemistry - ferromagnesian micas
DS201012-0618
2010
Reguir, E.Reguir, E., Chakhmouradian, A., Xu, C., Kynicky, J.An overview of geology, mineralogy and genesis of the giant REE-Fe-Nb deposit Bayan Obo, Inner Mongolia, China.International Workshop Geology of Rare Metals, held Nov9-10, Victoria BC, Open file 2010-10, extended abstract pp. 15-18.China, MongoliaCarbonatite
DS201112-0565
2011
Reguir, E.Kynicky, J., Cheng, Xu., Chakhmouradian, A.R., Reguir, E., Cihlarova, H., Brtnicky, M.REE mineralization of high grade REE-Ba-Sr and REE-Mo deposits in Mongolia and China.Goldschmidt Conference 2011, abstract p.1260.China, MongoliaCarbonatite
DS201112-0850
2001
Reguir, E.Reguir, E.Mineralogy of the Little Murun alkaline complex, Yakutia.Thesis: Msc. Lakehead University, Russia, YakutiaThesis - note availability based on request to author
DS201112-0851
2011
Reguir, E.Reguir, E.Amphibole in carbonatites: an equivocal petrogenetic indicator.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, AbstractCarbonatite
DS2000-0811
2000
Reguir, E.P.Reguir, E.P., Mitchell, R.H.The mineralogy of carbonatites and related potassic syenites from the Rocky Boy stock, Bearpaw Mountains.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000, 4p. abstract.MontanaCarbonatite - mineralogy, Deposit - Rocky Boy stock
DS2001-0164
2001
Reguir, E.P.Chakhnouradian, A.R., Reguir, E.P., Mitchell, R.H.Strontium apatite: new occurrence and the extent of the Calcium, Strontium substitution.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.24, abstract.Russia, Kola PeninsulaMineralogy, Lovozero
DS2002-0267
2002
Reguir, E.P.Chakhmouradian, A.R., Reguir, E.P., Mitchell, R.H.The crystal structure of a novel layered K Fe titanate and K, Ba and Pb bearing hollandite type titanates.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.289,90.GlobalMineralogy - titanates
DS2003-1152
2003
Reguir, E.P.Reguir, E.P., Chakmouradian, A.R., Mitchell, R.H.Pb bearing hollandite type titanates: a first natural occurrence and reconnaissanceMineralogical Magazine, Vol. 67, 5, pp. 957-66.GlobalMineralogy
DS200412-1649
2004
Reguir, E.P.Reguir, E.P., Chakmouradian, A.R., Mitchell, R.H.Pb bearing hollandite type titanates: a first natural occurrence and reconnaissance synthesis study.Mineralogical Magazine, Vol. 67, 5, pp. 957-965.RussiaMineralogy - Murun alkaline complex
DS200812-0192
2008
Reguir, E.P.Chakhmouradian, A.H., Bohm, C.O., Demeny, A., Reguir, E.P., Hegger, E., Halden, N.M., Yang, P.Kimberlite from Wekusko Lake, Manitoba: a diamond indicator bearing beforsite and not a kimberlite, after all.9IKC.com, 3p. extended abstractCanada, manitobaCarbonatite
DS200812-0194
2008
Reguir, E.P.Chakhmouradian, A.R., Demeny, A., Reguir, E.P., Hegner, E., Halden, N.M., Yang, P.'Kimberlite' from Wekusko Lake, Manitoba: re-assessment and implications for further exploration. Beforsite ( primary dolomite carbonatite)... 'notion' could beManitoba Geological Survey, Nov. 21, 1p. abstract.Canada, ManitobaPetrology - potentially diamondiferous
DS200812-0195
2008
Reguir, E.P.Chakhmouradian, A.R., Mitchell, R.H., Burns, P.C., Mikhailova, Yu., Reguir, E.P.Marianoite, a new member of the cuspidine group from the Prairie Lake silicocarbonatite.Canadian Mineralogist, Vol. 46, 4, August pp.Canada, OntarioCarbonatite
DS200812-0947
2008
Reguir, E.P.Reguir, E.P., Chakhmouradian, A.R., Halden, N.M., Yang, P., Zaitsev, A.N.Early magmatic and reaction induced trends in magnetite from the carbonatites of Kerimasi, Tanzania.Canadian Mineralogist, Vol. 46, 4, August pp.Africa, TanzaniaCarbonatite
DS200912-0623
2009
Reguir, E.P.Reguir, E.P., Chakmouradian, A.R., Halden, N.M., Malkovets, V.G., Yang, P.Major and trace element compositional variation of phlogopite from kimberlites and carbonatites as a petrogenetic indicator.Lithos, In press available, 50p.TechnologyGeochemistry - ferromagnesian micas
DS201012-0094
2009
Reguir, E.P.Chakhmouradian, A.R., Bohm, C.O., Demeny, A., Reguir, E.P., Hegner, E., Creaser, R.A., Halden, N.M., Yang, P.'Kimberlite' from Wekusko Lake Manitoba: actually a diamond indicator bearing dolomite carbonatite.Lithos, Vol. 112 S pp. 347-357.Canada, ManitobaCarbonatite
DS201012-0619
2010
Reguir, E.P.Reguir, E.P., Chakhmouradian, A.R., Halden, N.M., Yang, P.Trace element variations in clinopyroxene from calcite carbonatites.International Mineralogical Association meeting August Budapest, abstract p. 575.Canada, Ontario, Russia, Aldan Shield, Kola PeninsulaCarbonatite
DS201012-0620
2010
Reguir, E.P.Reguir, E.P., Chakhmouradian, A.R., Halden, N.M., Yang, P.Contrasting trends of trace element zoning in phlogopite from calcite carbonatites.International Mineralogical Association meeting August Budapest, abstract p. 575.United States, Colorado Plateau, Russia, Canada, Ontario, QuebecCarbonatite
DS201112-0852
2011
Reguir, E.P.Reguir, E.P., Xu, C., Kynicky, J., Coueslan, C.G.Amphibole in carbonatites: an equivocal petrogenetic indicator.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.126-128.MantleCarbonatite
DS201112-0853
2011
Reguir, E.P.Reguir, E.P., Xu, C., Kynicky, J., Coueslan, C.G.Amphibole in carbonatites: an equivocal petrogenetic indicator.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.126-128.MantleCarbonatite
DS201312-0136
2013
Reguir, E.P.Chakhmouradian, A.R., Reguir, E.P., Kamenetsky, V.S., Sharygin, V.V., Golovin, A.V.Trace element partitioning between perovskite and kimberlite to carbonatite melt: new experimental constraints.Chemical Geology, Vol. 353, pp. 112-131.MantleMineral chemistry
DS201312-0674
2013
Reguir, E.P.Osovetskii, B.M., Reguir, E.P., Chakhmouradian, A.R., Veksler, I.V., Yang, P., Kamanetsky, V.S., Camacho, A.Trace element analysis and U-Pb geochronology of perovskite and its importance for tracking unexposed rare metal and diamond deposits.GAC-MAC 2013 SS4: Diamond: from birth to the mantle emplacement in kimberlite., abstract onlyMantleGeochronology
DS201412-0111
2014
Reguir, E.P.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
DS201412-0112
2014
Reguir, E.P.Chakhmouradian, A.R., Reguir, E.P., Kressal, R.D., Crozier, J., Pisiak, L.K., Sidhu, R., Yang, P.Carbonatite hosted niobium deposit at Aley, northern British Columbia ( Canada): mineralogy, geochemistry and petrogenesis.Ore Geology Reviews, Vol. 64, pp. 642-666.Canada, British ColumbiaCarbonatite
DS201508-0344
2015
Reguir, E.P.Chakhmouradian, A.R., Reguir, E.P., Coueslan, C., Yang, P.Calcite and dolomite in intrusive carbonatites. II Trace element variations.Mineralogy and Petrology, in press available 17p.GlobalCarbonatite

Abstract: The composition of calcite and dolomite from several carbonatite complexes (including a large set of petrographically diverse samples from the Aley complex in Canada) was studied by electron-microprobe analysis and laser-ablation inductively-coupled-plasma mass-spectrometry to identify the extent of substitution of rare-earth and other trace elements in these minerals and the effects of different igneous and postmagmatic processes on their composition. Analysis of the newly acquired and published data shows that the contents of rare-earth elements (REE) and certain REE ratios in magmatic calcite and dolomite are controlled by crystal fractionation of fluorapatite, monazite and, possibly, other minerals. Enrichment in REE observed in some samples (up to ~2000 ppm in calcite) cannot be accounted for by coupled substitutions involving Na, P or As. At Aley, the REE abundances and chondrite-normalized (La/Yb)cn ratios in carbonates decrease with progressive fractionation. Sequestration of heavy REE from carbonatitic magma by calcic garnet may be responsible for a steeply sloping "exponential" pattern and lowered Ce/Ce* ratios of calcite from Magnet Cove (USA) and other localities. Alternatively, the low levels of Ce and Mn in these samples could result from preferential removal of these elements by Ce4+- and Mn3+-bearing minerals (such as cerianite and spinels) at increasing f(O2) in the magma. The distribution of large-ion lithophile elements (LILE = Sr, Ba and Pb) in rock-forming carbonates also shows trends indicative of crystal fractionation effects (e.g., concomitant depletion in Ba + Pb at Aley, or Sr + Ba at Kerimasi), although the phases responsible for these variations cannot be identified unambiguously at present. Overall, element ratios sensitive to the redox state of the magma and its complexing characteristics (Eu/Eu*, Ce/Ce* and Y/Ho) are least variable and in both primary calcite and dolomite, approach the average chondritic values. In consanguineous rocks, calcite invariably has higher REE and LILE levels than dolomite. Hydrothermal reworking of carbonatites does not produce a unique geochemical fingerprint, leading instead to a variety of evolutionary trends that range from light-REE and LILE enrichment (Turiy Mys, Russia) to heavy-REE enrichment and LILE depletion (Bear Lodge, USA). These differences clearly attest to variations in the chemistry of carbonatitic fluids and, consequently, their ability to mobilize specific trace elements from earlier-crystallized minerals. An important telltale indicator of hydrothermal reworking is deviation from the primary, chondrite-like REE ratios (in particular, Y/Ho and Eu/Eu*), accompanied by a variety of other compositional changes depending on the redox state of the fluid (e.g., depletion of carbonates in Mn owing to its oxidation and sequestration by secondary oxides). The effect of supergene processes was studied on a single sample from Bear Lodge, which shows extreme depletion in Mn and Ce (both due to oxidation), coupled with enrichment in Pb and U, possibly reflecting an increased availability of Pb2+ and (UO2)2+ species in the system. On the basis of these findings, several avenues for future research can be outlined: (1) structural mechanisms of REE uptake by carbonates; (2) partitioning of REE and LILE between cogenetic calcite and dolomite; (3) the effects of fluorapatite, phlogopite and pyrochlore fractionation on the LILE budget of magmatic carbonates; (4) the cause(s) of coupled Mn-Ce depletion in some primary calcite; and (5) relations between fluid chemistry and compositional changes in hydrothermal carbonates.
DS201508-0345
2015
Reguir, E.P.Chakhmouradian, A.R., Reguir, E.P., Zaitsev, A.N.Calcite and dolomite in intrusive carbonatites. I Textural variastions.Mineralogy and Petrology, in press available 28p.GlobalCarbonatite

Abstract: Carbonatites are nominally igneous rocks, whose evolution commonly involves also a variety of postmagmatic processes, including exsolution, subsolidus re-equilibration of igneous mineral assemblages with fluids of different provenance, hydrothermal crystallization, recrystallization and tectonic mobilization. Petrogenetic interpretation of carbonatites and assessment of their mineral potential are impossible without understanding the textural and compositional effects of both magmatic and postmagmatic processes on the principal constituents of these rocks. In the present work, we describe the major (micro)textural characteristics of carbonatitic calcite and dolomite in the context of magma evolution, fluid-rock interaction, or deformation, and provide information on the compositional variation of these minerals and its relation to specific evolutionary processes.
DS201510-1761
2014
Reguir, E.P.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.
DS201604-0627
2016
Reguir, E.P.Sheng, A.R., Reguir, E.P., Chakmouradian, A.R., Elliott, B.Mud Lake dyke ( Northwest Territories, Canada) revisited: a mid-Ordovician oxidized dolomite kimberlite.GAC MAC Meeting Special Session SS11: Cratons, kimberlites and diamonds., abstract 1/4p.Canada, Northwest TerritoriesDeposit - Mud Lake
DS201707-1313
2017
Reguir, E.P.Chakhmouradian, A.R., Cooper, M.A., Reguir, E.P., Moore, M.A.Carbocernaite from Bear Lodge, Wyoming: crystal chemistry, paragenesis, and rare earth fractionation on a microscale.American Mineralogist, Vol. 102, pp. 1340-1352.United States, Wyoming, Colorado Plateaucarbonatite - Bear Lodge

Abstract: Zoned crystals of carbocernaite occur in hydrothermally reworked burbankite-fluorapatite-bearing calcite carbonatite at Bear Lodge, Wyoming. The mineral is paragenetically associated with pyrite, strontianite, barite, ancylite-(Ce), and late-stage calcite, and is interpreted to have precipitated from sulfate-bearing fluids derived from an external source and enriched in Na, Ca, Sr, Ba, and rare-earth elements (REE) through dissolution of the primary calcite and burbankite. The crystals of carbocernaite show a complex juxtaposition of core-rim, sectoral, and oscillatory zoning patterns arising from significant variations in the content of all major cations, which can be expressed by the empirical formula (Ca0.43–0.91Sr0.40–0.69REE0.18–0.59Na0.18–0.53Ba0–0.08)?1.96–2.00(CO3)2. Interelement correlations indicate that the examined crystals can be viewed as a solid solution between two hypothetical end-members, CaSr(CO3)2 and NaREE(CO3)2, with the most Na-REE-rich areas in pyramidal (morphologically speaking) growth sectors representing a probable new mineral species. Although the Bear Lodge carbocernaite is consistently enriched in light REE relative to heavy REE and Y (chondrite-normalized La/Er = 500–4200), the pyramidal sectors exhibit a greater degree of fractionation between these two groups of elements relative to their associated prismatic sectors. A sample approaching the solid-solution midline [(Ca0.57Na0.42)?0.99(Sr0.50REE0.47Ba0.01)?0.98(CO3)2] was studied by single-crystal X-ray diffraction and shown to have a monoclinic symmetry [space group P11m, a = 6.434(4), b = 7.266(5), c = 5.220(3) Å, ? = 89.979(17)°, Z = 2] as opposed to the orthorhombic symmetry (space group Pb21m) proposed in earlier studies. The symmetry reduction is due to partial cation order in sevenfold-coordinated sites occupied predominantly by Ca and Na, and in tenfold-coordinated sites hosting Sr, REE, and Ba. The ordering also causes splitting of carbonate vibrational modes at 690–740 and 1080–1100 cm?1 in Raman spectra. Using Raman micro-spectroscopy, carbocernaite can be readily distinguished from burbankite- and ancylite-group carbonates characterized by similar energy-dispersive spectra.
DS201709-2050
2017
Reguir, E.P.Salnikova, E.B., Chakhmouradian, A.R., Stifeeva, M.V., Reguir, E.P., Nikiforov, A.V.Calcic garnets as a promising U-Pb geochronometers. Kola PeninsulaGoldschmidt Conference, abstract 1p.Russiacarbonatite, Belyaya Zima

Abstract: Calcic garnets are an important – although somewhat neglected – member of the garnet group. Typically, these mineral are members of complex solid solutions involving largely substitutions in the Fe3+/Al and Si sites and at least eight different end-members. The absolute majority of garnets in this family are Ti-Mg-Fe2+(± Al ± Zr)-bearing andradite transitional to morimotoite and schorlomite. Importantly, these garnets occur as common accessory minerals in a wide range of igneous and rocks, including nepheline syenites, alkali feldspar syenites, melteigite-urtites, nephelinites, melilitolites, melilitites, calcite carbonatites, ultramafic lamprophyres, orangeites, contaminated kimberlites, skarns and rodingites. Calcic garnets have a great capacity for atomic substitutions involving high-field-strength elements and, even more importantly, rare earths (up to 4000 ppm, including Y), Th and U (both up to 100 ppm) at low levels of common Pb. Their (La/Yb)cn ratio varies over two orders of magnitude (from < 0.01 to ~1), making these minerals a sensitive indicator of crystal fractionation, degassing and other magma-evolution processes. Given these unique compositional characteristics and surprising lack of interest in these minerals in the previous literature, we explored the possibility of using calcic garnets as a U-Pb geochronometer. For this purpose, we selected samples of well-crystallized igneous garnet from four very different rock types of different age, including: carbonatite (Afrikanda) from the Devonian Kola Alkaline Province, carbonatite from the Neoproterozoic Belaya Zima complex (Central-Asian mobile belt), ijolite from the Chick Ordovician igneous complex (Central-Asian mobile belt), granitic pegmatite from the Eden Lake complex in the Paleoproterozoic Trans-Hudson orogen, and feldspathoid syenite from the Cinder Lake alkaline complex in the Archean Knee Lake greenstone belt. U-Pb TIMS ages of the studied garnets are mostly concordant and reveal perfect correspondence with reported U-Pb zircon or perovskite ages as well as Sm-Nd isochrone age for these complexes. Therefore we can advertise calcic garnets as a promising tool for U-Pb geochronological studies.
DS201801-0053
2017
Reguir, E.P.Reguir, E.P., Chakhmouradian, A.R., Zaitsev, A.N., Yang, P.Trace element variations and zoning in phlogopite from carbonatites and phoscorites.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 8-9.carbonatites

Abstract: Phlogopite from carbonatites and phoscorites worldwide shows three major types of core-to-rim trends of compositional variation: Ba+Al-, Fe and Fe+Al enrichment. These major-element trends are accompanied by largely consistent changes in traceelement abundances. Uptake of Rb, Sr, Ba, Sc, V, Mn and HFSE by phlogopite is susceptible to changes in the availability of these elements due to precipitation of other early silicate and oxide phases (especially, magnetite, apatite and niobates). In rare cases, more complex oscillatory and sector patterns are juxtaposed over the principal evolutionary trend, indicating kinetic and crystal-chemical controls over element uptake. Phlogopite is a common accessory to major constituent of carbonatites and genetically related rocks (including phoscorites). Major-element variations of phlogopite from these rocks have been addressed in much detail in the literature (for references, see Reguir et al. 2009), whereas its trace-element characteristics and zoning patterns have so far received little attention. In this work, we examined the compositional variation of phlogopite from 23 carbonatite and phoscorite localities worldwide. The major-element compositions were determined using wavelength-dispersive X-ray spectrometry (WDS) and trace-element abundances by laser-ablation inductively-coupled-plasma mass-spectrometry (LA-ICPMS). Previously, two major core-to-rim zoning trends have been identified in micas from calcite carbonatites (Reguir et al. 2009, 2010). Phlogopite from Oka (Canada) and Iron Hill (USA), for example, involves an increase in kinoshitalite component rim-ward, accompanied by enrichment in high-field-strength elements (HFSE = Zr, Nb, Ta), Sr and Sc. At most other carbonatite localities (e.g., Kovdor in Russia, or Prairie Lake in Canada), phlogopite crystals exhibit rim-ward enrichment in Fe. In the present work, we confirmed these two common types of zoning, and identified new patterns that have not been reported in the previous literature. In addition to the common Fe-enrichment trend, which occurs in both carbonatites (e.g., Guli in Russia and Sokli in Finland) and phoscorites (e.g., Aley in Canada), we identified a Fe-Al-enrichment subtype of this zoning pattern observed, for example, in samples from the Shiaxiondong calcite carbonatite (China). Overall, the Fe-enrichment pattern is accompanied by rim-ward depletion in Ba, Rb and HFSE, coupled with enrichment in Mn. Other trace elements exhibit no consistent variation among the studied samples. The Shiaxiondong material is characterized by the highest recorded Rb values, ranging from 1120 to 660 ppm. Phlogopite from the Kovdor calcite-forsterite-magnetite phoscorite contains the highest recorded levels of Nb and Ta, ranging from 320 ppm and 40 ppm, respectively, in the core to 85 ppm and 4 ppm in the rim. The maximum levels of Zr (up to 50 ppm) were observed in the core of Prairie Lake phlogopite, whereas its rim contains the highest measured Mn content (up to 4100 ppm). The levels of Sc are typically below 100 ppm in samples from calcite and dolomite carbonatites, but may reach 280 ppm in phoscorites. Interestingly, phlogopite from phoscorites shows rim-ward enrichment in Sc, whereas the opposite trend is observed in carbonatitic micas. Phlogopite from calcite carbonatites at Zibo (China) and Valentine Township (Canada), and from phoscorites at Aley (Canada) shows an unusual zoning pattern involving depletion in Fe, which is accompanied by a decrease in Al, Ba, Sr, Zr, Hf, Y, Sc and V abundances. The concentrations of other trace elements, including Nb and Ta show inconsistent variations. In the Aley phoscorite, phlogopite is enriched in Ba (up to 15000 ppm in the core and < 7500 ppm in the rim), but poor in Sr (80 and 35 ppm in the core and rim, respectively) relative to those from the Zibo and Valentine carbonatites. Zirconium levels reach 200 and 170 ppm in the core, and drop to < 40 and 60 ppm in the rim of the Valentine and Zibo samples, respectively. In the Aley sample, the content of Zr does not exceed 55 ppm. The Zibo sample is also enriched in V (up to 230 and 160 ppm in the core and rim, respectively) relative to the two other samples (< 100 ppm V). The Sc and Hf levels are consistently low (less than 30 and 4 ppm, respectively). In addition to simple core-rim patterns, phlogopite from carbonatites and phoscorites may exhibit oscillatory zoning, which involves periodic variations in Fe/Mg ratio. Iron-rich zones are relatively depleted in Mn, but enriched in Nb. One sample of phoscoritic phlogopite (Aley) exhibits striking sector zoning juxtaposed over the overall Feenrichment trend and Fe-Mg oscillations. In terms of major elements, basal sectors perpendicular to [001] are enriched in Fe and Al, but depleted in Mg and K relative to the flank sectors. This enrichment is accompanied by higher Ba, Sr and HFSE levels in the basal sector. Our data confirm that there is no universal pattern of zoning in carbonatitic or phoscoritic phlogopite, and variations in the content of most trace elements are strongly coupled to major-element patterns. Three major core-to-rim variation trends, as well as juxtaposed oscillatory and sector patterns, can be recognized. The observed compositional variations indicate that, in the majority of cases, the trace-element composition of phlogopite is controlled by partitioning of Rb, Sr, Ba, Sc, V, Mn and HFSE between this mineral, its parental magma, and co-precipitating early phases. Among the latter, magnetite, apatite and niobates appear to exert the greatest influence on element distributions. More complex oscillatory and sector patterns imply the presence of kinetic and crystal-chemical controls over element uptake in certain carbonatitic systems
DS202109-1487
2021
Reguir, E.P.Reguir, E.P., Salinkova, E.B., Yang, P., Chakmouradian, A.R., Stifeeva, M.V., Rass, I.T., Kotov, A.B.U-Pb geochronology of calcite carbonatites and jacupirangite from the Guli alkaline complex, Polar Siberia, Russia.Mineralogical Magazine, Vol. 85, 4, pp. 469-483.Russia, Siberiadeposit - Guli

Abstract: Mantle xenoliths from the Middle-Late Jurassic Obnazhennaya kimberlite are often compared with those from the Udachnaya kimberlite (ca. 367 Ma) to inform the evolution of the Siberia craton. However, there are no direct constraints on the timing of the Obnazhennaya kimberlite eruption. Such uncertainty of the kimberlite age precludes a better understanding of the mantle xenoliths from the Obnazhennaya pipe, and thus also of the evolution of the Siberia craton. This paper reports U-Pb ages for both perovskite from the Obnazhennaya kimberlite and rutile in an Obnazhennaya eclogite xenolith. The fresh perovskite formed during the early stage of magmatic crystallization and yields a U-Pb age of 151.8 ± 2.5 Ma (2?). Rutile in the eclogite xenolith yields an overlapping U-Pb age of 154.2 ± 1.9 Ma (2?). Because rutile has a Pb closure temperature lower than the inferred residence temperature of the eclogite prior to eruption, the U-Pb isotope system in rutile was not closed until the host eclogite was entrained and delivered to the surface by the kimberlite and therefore records the timing of kimberlite eruption. These data provide the first direct constraints on the emplacement age of the Obnazhennaya kimberlite and add to the global ‘kimberlite bloom’ from ca. 250-50 Ma as well as to the largest pulse of kimberlite volcanism in Siberia from ca. 171-144 Ma. The timing of this Jurassic-Cretaceous pulse coincides with the closure of the Mongol-Okhotsk Ocean, but the depleted Sr-Nd isotopic characteristics of 171-144 Ma kimberlites are inconsistent with a subduction-driven model for their petrogenesis. Thus, the closure of the Mongol-Okhotsk Ocean may act as a trigger for the initiation of 171-144 Ma kimberlite emplacement of Siberia, but was not the source.
DS201112-0186
2011
Reguir, K.Chilarova, H., Kynicky , Cheng, X., Song, W., Chalmouradian, A., Reguir, K.The largest deposit of strategic REE Bayan Obo, geological situation and environmental hazards.Goldschmidt Conference 2011, abstract p.677.ChinaCarbonatite, bastnaesite
DS2002-0264
2002
Reguirm E.P.Chakhmouradian, A.B., Reguirm E.P., Mitchell, R.H.Strontium apatite: new occurrences, and the extent of Sr for Ca substitution in apatite group minerals.Canadian Mineralogist, Vol.40,1,Feb.pp. 121-36.Russia, Northwest TerritoriesAlkaline rocks, Deposit - Lovozero, Murun, Lac de Gras
DS200612-0851
2006
Rehault, J-P.Maillard, A., Malod, J., Thiebot, E., Klingelhoefer, F., Rehault, J-P.Imaging a lithospheric detachment at the continent ocean crustal transition off Morocco.Earth and Planetary Science Letters, Vol. 241, 3-4, Jan. 31, pp. 686-698.Africa, MoroccoGeophysics - seismics, exhumation
DS1860-1044
1898
Rehbok, TH.Rehbok, TH.Deutsch Sued West Afrika, Sein Wirtschaftliche ErschleiszungBerlin:, Africa, NamibiaTravelogue
DS1995-0422
1995
Reheis, M.C.Dixon, T.H., Robaudo, S., Lee, J., Reheis, M.C.Constraints on present day Basin and Range deformation from space geodesyTectonics, Vol. 14, No. 4, August pp. 755-772Cordillera, Basin and RangeTectonics, Deformation zones
DS2003-0416
2003
Rehfeldt, T.Foley, S.F., Buhre, S., Jacob, D.E., Rehfeldt, T.Pyroxenite and dunite xenoliths as metamorphosed cumulates from the Archean lower8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractGlobalEclogites and Diamonds
DS200712-0883
2006
Rehfeldt, T.Rehfeldt, T., Foley, S.F., Jacob, D.E.Restoration of premetasomatic protolith compositions in mantle xenoliths.Geochimica et Cosmochimica Acta, In press availableMantleMetasomatism
DS200712-0884
2007
Rehfeldt, T.Rehfeldt, T., Foley, S.F., Jacob, D.E., Carlson, R.W.Characterizing Fe rich dunite xenoliths as cumulates of Phanerozoic and Archean flood basalt magmatism.Plates, Plumes, and Paradigms, 1p. abstract p. A827.Africa, South AfricaKimberley Cluster
DS200712-0885
2007
Rehfeldt, T.Rehfeldt, T., Jacob, D.E., Carlson, R.W., Foley, S.F.Fe rich dunite xenoliths from South African kimberlites: cumulates from Karoo flood basalts.Journal of Petrology, Vol. 48, 7, pp. 1387-1409.Africa, South AfricaMineral chemistry
DS200712-0886
2007
Rehfeldt, T.Rehfeldt, T., Obst, K., Johannson, L.Petrogenesis of ultramafic and mafic xenoliths from Mesozoic basanites in southern Sweden: constraints from mineral chemistry.International Journal of Earth Sciences, Vol. 96, 3, pp. 433-450.Europe, SwedenBasanites, Foidites
DS200712-0887
2007
Rehfeldt, T.Rehfeldt, T., Obst, K., Johansson, L.Petrogenesis of ultramafic and mafic xenoliths from Mesozoic basanites in southern Sweden: constraints from mineral chemistry.International Journal of Earth Sciences, Vol. 96, 3, pp. 433-450.Europe, SwedenBasanites, Foidites
DS200812-0948
2008
Rehfeldt, T.Rehfeldt, T., Foley, S.F., Jacob, D.E., Carlson, R.W., Lowry, D.Contrasting types of metasomatism in dunite, wehrlite and websterite xenoliths from Kimberley, South Africa.Geochimica et Cosmochimica Acta, Vol. 73, 23, Dec. 1. pp. 5722-5756.Africa, South AfricaDeposit - Kimberley
DS200812-0949
2007
Rehfeldt, T.Rehfeldt, T., Jacob, D.E., Carlson, R.W., Foley, S.F.Fe rich dunite xenoliths from South African kimberlites: cumulates from Karoo flood basalts.Journal of Petrology, Vol. 48, pp. 1387-1409.Africa, South AfricaXenoliths
DS201012-0621
2010
Rehfeldt, T.Rehfeldt, T., Foley, S.F., Jacob, D.E., Pearson, D.G.Trace elements in mantle olivine and orthopyroxene from the North Atlantic and Kaapvaal Cratons.Goldschmidt 2010 abstracts, abstractAfrica, South Africa, EuropeGeochemistry
DS201312-0271
2013
Rehfeldt, T.Foley, S.F., Prelevic, D., Rehfeldt, T., Jacob, D.E.Minor and trace elements in olivines as probes into early igneous and mantle melting.Earth and Planetary Science Letters, Vol. 363, pp. 181-191.MantleMetasomatism
DS2001-0482
2001
Rehkamper, M.Hoch, M., Rehkamper, M., Tobsachall, H.J.Strontium, neodymium, lead, Oxygen isotopes of minettes from Schirmacher Oasis: a case of mantle me tasomatism involving subduction....Journal of Petrology, Vol. 42, No. 7, July pp. 1387-1400.GlobalContinental material - subduction, Minettes
DS201112-0433
2011
Rehkamper, M.Hettmann, K., Marks, M., Kressing, K., Zack, T., Wenzel, T., Rehkamper, M., Jacob, D., Markl, G.The geochemistry of thallium and its isotopes in a peralkaline magmatic system.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologyMagmatism
DS201212-0195
2012
Rehr, J.R.Farges, F., Vinson, J., Rehr, J.R., Post, J.E.Spectroscopy of B doped diamonds: experiment vs. theory. Hope, Tavernier Blue, French Blueemc2012 @ uni-frankfurt.de, 1p. AbstractTechnologyDiamond - colour
DS201702-0201
2017
Rehuir, E.P.Chakhmouradian, A.R., Rehuir, E.P., Zaitsev, A.N., Coueslan, C., Xu, C., Kynicky, J., Hamid Mumin, A., Yang, P.Apatite in carbonatitic rocks: compositional variation, zoning, element partitioning and petrogeneitic significance.Lithos, in press available, 138p.TechnologyCarbonatite

Abstract: The Late Cretaceous (ca. 100 Ma) diamondiferous Fort à la Corne (FALC) kimberlite field in the Saskatchewan (Sask) craton, Canada, is one of the largest known kimberlite fields on Earth comprising essentially pyroclastic kimberlites. Despite its discovery more than two decades ago, petrological, geochemical and petrogenetic aspects of the kimberlites in this field are largely unknown. We present here the first detailed petrological and geochemical data combined with reconnaissance Nd isotope data on drill-hole samples of five major kimberlite bodies. Petrography of the studied samples reveals that they are loosely packed, clast-supported and variably sorted, and characterised by the presence of juvenile lapilli, crystals of olivine, xenocrystal garnet (peridotitic as well as eclogitic paragenesis) and Mg-ilmenite. Interclast material is made of serpentine, phlogopite, spinel, carbonate, perovskite and rutile. The mineral compositions, whole-rock geochemistry and Nd isotopic composition (Nd: + 0.62 to ? 0.37) are indistinguishable from those known from archetypal hypabyssal kimberlites. Appreciably lower bulk-rock CaO (mostly < 5 wt%) and higher La/Sm ratios (12-15; resembling those of orangeites) are a characteristic feature of these rocks. Their geochemical composition excludes any effects of significant crustal and mantle contamination/assimilation. The fractionation trends displayed suggest a primary kimberlite melt composition indistinguishable from global estimates of primary kimberlite melt, and highlight the dominance of a kimberlite magma component in the pyroclastic variants. The lack of Nb-Ta-Ti anomalies precludes any significant role of subduction-related melts/fluids in the metasomatism of the FALC kimberlite mantle source region. Their incompatible trace elements (e.g., Nb/U) have OIB-type affinities whereas the Nd isotope composition indicates a near-chondritic to slightly depleted Nd isotope composition. The Neoproterozoic (~ 0.6-0.7 Ga) depleted mantle (TDM) Nd model ages coincide with the emplacement age (ca. 673 Ma) of the Amon kimberlite sills (Baffin Island, Rae craton, Canada) and have been related to upwelling protokimberlite melts during the break-up of the Rodinia supercontinent and its separation from Laurentia (North American cratonic shield). REE inversion modelling for the FALC kimberlites as well as for the Jericho (ca. 173 Ma) and Snap Lake (ca. 537 Ma) kimberlites from the neighbouring Slave craton, Canada, indicate all of their source regions to have been extensively depleted (~ 24%) before being subjected to metasomatic enrichment (1.3-2.2%) and subsequent small-degree partial melting. These findings are similar to those previously obtained on Mesozoic kimberlites (Kaapvaal craton, southern Africa) and Mesoproterozoic kimberlites (Dharwar craton, southern India). The striking similarity in the genesis of kimberlites emplaced over broad geological time and across different supercontinents of Laurentia, Gondwanaland and Rodinia, highlights the dominant petrogenetic role of the sub-continental lithosphere. The emplacement of the FALC kimberlites can be explained both by the extensive subduction system in western North America that was established at ca. 150 Ma as well as by far-field effects of the opening of the North Atlantic ocean during the Late Cretaceous.
DS202103-0413
2021
Reibelt, L.M.Stoudmann, N., Reibelt, L.M., Rakotomalala, A.G., Randriamanjakahasina, O., Garcia, C.A., Waeber, P.O.A double edged sword: realities of artisanal and small scale mining for rural people in the Alaotra region of Madagascar. ** not specific to diamondsNatural Resources Forum, Vol 45 pp. 87-102. pdfAfrica, Madagascaralluvials

Abstract: A growing number of people are entering the artisanal and small?scale mining (ASM) sector worldwide. In Madagascar, millions of individuals depend on this informal activity. Through a case study in the Alaotra?Mangoro region of Madagascar, our research aimed to understand the "bottom?up" dynamics and ripple effects of the sector, by looking at the realities for rural communities where inhabitants are both directly and indirectly affected by ASM. We were interested in community members' and miners' perceptions of the socio?economic and environmental impacts of ASM, and in identifying the factors attracting people living in one of the country's agricultural hubs to this activity. Our results show a wide diversity of push and pull factors leading people to enter the sector. Although many positive impacts of ASM exist for miners and communities within the vicinity of mines, most miner participants considered themselves worse off since starting to mine, highlighting the high risk and low probability of return of ASM. ASM's potential for local and national development will remain squandered if its negative impacts continue to go unmanaged. Accounting for local contexts and the ripple effects of ASM will be crucial in achieving safety and security for miners, and to tap into the benefits it may offer communities while minimising environmental damage.
DS1993-0631
1993
Reiber, M.Harris, D.P., Reiber, M.Evaluation of the United States Geological Survey (USGS)'s three step assessmentmethodologyUnited States Geological Survey (USGS) Open File, No. 93-0258 A, B, 675p. $ 101. 75 discs $ 20.00United StatesEconomics, Assessment methodology
DS1985-0557
1985
Reiche, M.Reiche, M., Bautsch, H.J.Electron Microscopial Study of Garnet Exsolution in Orthopyroxene.Physics Chem. Minerals, Vol. 12, No. 1, PP. 12-33.East GermanyEclogite
DS1991-1299
1991
Reichenbach, I.Parrish, R.R., Reichenbach, I.Age of xenocrystic zircon from diatremes of western CanadaCanadian Journal of Earth Sciences, Vol. 28, No. 8, August pp. 1232-1238British Columbia, Northwest TerritoriesDiatremes, Geochronology -zircons
DS200812-0649
2007
Reicherter, K.Lerche, I., Reicherter, K.Uplift and mantle thickness: a sensitivity study.Energy Exploration Exploitation, Multi-Science Publishing Co., Vol. 25, 4, August pp. 273-299. IngentaMantleGeophysics - seismics
DS201812-2883
2018
Reichhardt, F.Sims, K., Fox, K., Harris, M., Chimuka, L., Reichhardt, F., Muchemwa, E., Gowera, R., Hinks, D., Smith, C.B.Murowa deposit: Discovery of the Murowa kimberlites, Zimbabwe.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 359-378.Africa, Zimbabwedeposit - Murowa
DS1989-1112
1989
Reichle, H.G. Jr.Newell, R.E., Reichle, H.G. Jr., Seller, W.Carbon monoxide and the burning earthScientific American, Vol. 261, No. 4, October, pp. 82-89. Database # 18158GlobalAtmosphere, Carbon monoxide
DS2003-0349
2003
Reichow, M.K.Downes, H., Reichow, M.K., Mason, P.R.D., Beard, A.D., Thirlwall, M.F.Mantle domains in the lithosphere beneath the French Massif Central: trace element andChemical Geology, Vol. 200, 1-2, Oct. 16, pp. 71-87.Europe, FranceGeochronology, Peridotites
DS200412-0479
2003
Reichow, M.K.Downes, H., Reichow, M.K., Mason, P.R.D., Beard, A.D., Thirlwall, M.F.Mantle domains in the lithosphere beneath the French Massif Central: trace element and isotopic evidence from mantle clinopyroxeChemical Geology, Vol. 200, 1-2, Oct. 16, pp. 71-87.Europe, FranceGeochronology, peridotites
DS2001-0347
2001
ReidFunck, T., Louden, Hall, Wardle, Salisbury, ReidSynthesis of the Escoot 1996 refraction seismic studies in the Torngat Orogen.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.48, abstract.Quebec, Labrador, UngavaGeophysics - seismics, ESCOOT.
DS1989-1257
1989
Reid, A.F.Reid, A.F.Measuring the unmeasureable - recent advances in applied mineralogyAustralasian Institute of Mining and Metallurgy, Vol. 294, No. 2, May pp. 20-24. Database # 17884GlobalOverview, Mineralogical techniques
DS1989-1258
1989
Reid, A.F.Reid, A.F.Measuring the unmeasureable- recent advances in applied mineralogyAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin Proceedings, Vol. 294, No. 2, April, pp. 20-24GlobalQEM scanning electron microscope (SEM) systems, Diamonds -brief
DS200612-0116
2006
Reid, A.J.Belousova, E.A., Reid, A.J., Griffin, W.L., O'Reilly, S.Y.Proterozoic rejuvenation of the Archean crust tracked by U Pb and hf isotopes in detrital zircon.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.AustraliaGeochronology
DS200912-0049
2009
Reid, A.J.Belousova, E.A., Reid, A.J., Griffin, W.L., O'Reilly, S.Y.Rejuvenation vs recycling of Archean crust in the Gawler Craton, south Australia: evidence from U Pb and Hf isotopes in detrital zircon.Lithos, In press - available 52p.AustraliaGeochronology
DS1970-0064
1970
Reid, A.M.Dawson, J.B., Powell, D.G., Reid, A.M.Ultrabasic Lava and Xenoliths from the Lashaine Volcano, Northern Tanganyika.Journal of PETROLOGY, Vol. 11, PP. 519-548.Tanzania, East AfricaRelated Rocks, Geology
DS1970-0065
1970
Reid, A.M.Dawson, J.B., Reid, A.M.A Pyroxenite Ilmenite Intergrowth from the Monastery Mine South Africa.Contributions to Mineralogy and Petrology, Vol. 26, PP. 296-301.South AfricaGeology, Inclusions, Xenoliths
DS1970-0180
1970
Reid, A.M.Reid, A.M., Hanor, J.S.Pyrope in KimberliteAmerican MINERALOGIST., Vol. 55, PP. 1374-1379.South AfricaInclusions, Mineralogy
DS1970-0587
1972
Reid, A.M.Reid, A.M., Dawson, J.B.Olivine Garnet Reaction in Peridotites from TanzaniaLithos, Vol. 5, PP. 115-124.Tanzania, East AfricaMineralogy
DS1970-0669
1973
Reid, A.M.Donaldson, C., Reid, A.M., Ridley, W.I.The Igwisi Hills Extrusive Kimberlites1st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 93-94.Tanzania, East AfricaGeology
DS1975-0168
1975
Reid, A.M.Reid, A.M., Donaldson, C., Dawson, J.B., Brown, R.W.The Igwisi Hills Extrusive KimberlitePhysics and Chemistry of the Earth., Vol. 9, PP. 199-218.Tanzania, East AfricaGeology
DS1975-0169
1975
Reid, A.M.Reid, A.M., Donaldson, C.H., Brown, R.W., Ridley, R.I., Dawson.Mineral Chemistry of Peridotite Xenoliths from the Lashainevolcano, Tanzania.Physics and Chemistry of the Earth., Vol. 9, PP. 525-544.Tanzania, East AfricaMineral Chemistry
DS1975-0391
1976
Reid, A.M.Reid, A.M., Brown, R.W., Dawson, J.B., Whitfield, G.G., Siebert.Garnet and Pyroxene Composition in Some Diamondiferous Eclogites.Contributions to Mineralogy and Petrology, Vol. 58, PP. 203-220.Tanzania, East AfricaPetrography, Mineral Chemistry
DS1982-0179
1982
Reid, A.M.Donaldson, C.H., Reid, A.M.Multiple Intrusion in a Kimberlite DykeGeological Society of South Africa Transactions, Vol. 85, No. 1, PP. 1-12.South AfricaDe Beers, Kimberley Area, Kimberlite Pipe And Deposit, Petrogra
DS1986-0144
1986
Reid, A.M.Clement, C.R., Reid, A.M.The origin of kimberlite pipes: an interpretation based on asynthesis of geological features displayed by southern Africa occurrences #1Proceedings of the Fourth International Kimberlite Conference, Held, No. 16, pp. 167-169South AfricaBlank
DS1989-0271
1989
Reid, A.M.Clement, C.R., Reid, A.M.The origin of kimberlite pipes: an interpretation based on a synthesis of geological features displayed by southern African occurrences #2Geological Society of Australia Inc. Blackwell Scientific Publishing, No. 14, Vol. 1, pp. 632-646South AfricaKimberlite formation, Kimberlite morphology
DS1996-0819
1996
Reid, A.M.Le Roex, A.P., Watkins, R.T., Reid, A.M.Geochemical evolution of the Okenyenya sub-volcanic ring complex, northwestern Namibia.Geology Magazine, Vol. 133, No. 6, pp. 645-670.NamibiaGeochemistry, Alkaline rocks
DS1996-1563
1996
Reid, A.M.Woronow, A., Reid, A.M., Jones, J.H.Parental magma compositions inferred from the chemical compositions of olivine controlled derivative meltsGeochimica et Cosmochimica Acta, Vol. 60, No. 4, Feb. 1, pp. 577-586GlobalMagma, Geochemistry
DS1970-0977
1974
Reid, A.R.Reid, A.R.Proposed Origin for Guianian DiamondsGeology, Vol. 2, No. 2, PP. 67-68.GlobalDiamond Genesis
DS1975-0392
1976
Reid, A.R.Reid, A.R.An Attempt to Localize Kimberlite Source Areas for Venezuelan Diamonds from Stratigraphy and Analysis of Diamond Mineral Inclusions.Ph.d. Thesis, Colorado School of Mines, 121P.VenezuelaKimberlite, Kimberley, Geochemistry
DS1987-0304
1987
Reid, D.L.Hunter, D.R., Reid, D.L.Mafic dyke swarms in southern Africain: Mafic dyke swarms, Editors Halls, H.C., Fahrig, W.F., Geological, Special Paper 34, pp. 445-456Southern AfricaKimberley p. 448, Transkei-Namibia p. 454, Kimberlite, Melilite
DS1991-0304
1991
Reid, D.L.Cooper, A.F., Reid, D.L.Textural evidence for calcite carbonatite magmas, Dicker-Willem, SouthwestNamibiaGeology, Vol. 19, No. 12, December pp. 1193-1196NamibiaCarbonatite, Texture, calcite
DS1991-1410
1991
Reid, D.L.Reid, D.L.Alkaline rocks in the Kuboos-Bremen igneous province, southern Namibia. The Kanabeam multiple ring complexCommunications of the Geological Survey of Namibia, Vol. 7, pp. 3-14NamibiaAlkaline rocks, Ring complex
DS1992-1266
1992
Reid, D.L.Reid, D.L., Cooper, A.F.Oxygen and carbon isotope patterns in the Dicker-Willem carbonatitecomplex, southern NamibiaChemical Geology, Vol. 94, No. 4, May 15, pp. 293-305NamibiaCarbonatite, Geochronology
DS1995-0351
1995
Reid, D.L.Cooper, A.F., Paterson, L.A., Reid, D.L.Lithium in carbonatites - consequence of an enriched mantle sourceMineralogical Magazine, Vol. 59, No. 396, Sept. pp. 410-408.GlobalCarbonatite
DS1997-0215
1997
Reid, D.L.Cooper, A.F., Reid, D.L.Nepheline sovites; parental carbonatite magmas and source of cumulate ijolites and urtites...Dicker WilleM.Geological Association of Canada (GAC) Abstracts, NamibiaCarbonatite, nepheline sovites, ijolites, urtites, Deposit - Dicker WilleM.
DS1997-0949
1997
Reid, D.L.Reid, D.L.Sm neodymium age and rare earth elements (REE) geochemistry of Proterozoic arc related igneous rocks In the Richtersveld subprovinceJournal of African earth Sciences, Vol. 24, No. 4, pp. 621-633Southern AfricaNamaqua Mobile Belt, Geochronology
DS1998-0274
1998
Reid, D.L.Cooper, A.F., Reid, D.L.Nepheline sovites as parental magmas in carbonatite complexes, evidence from Dicker Willem, southwest Namibia.Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2123-36.Namibia, southwestCarbonatite, nepheline - sovite, Deposit - Dicker WilleM.
DS1998-1224
1998
Reid, D.L.Reid, D.L., Cooper, A.F.Carbonatite and silicate magmas at Dicker Willem, southern Namibia: their origin and source region...7th. Kimberlite Conference abstract, pp. 727-9.NamibiaCarbonatite, characteristics, Deposit - Dicker WilleM.
DS2000-0180
2000
Reid, D.L.Cooper, A.F., Reid, D.L.The association of potassic trachytes and carbonatites at the Dicker Willem Complex, not cogenetic magmas.....Contributions to Mineralogy and Petrology, Vol. 139, No. 5, pp. 570-83.NamibiaCarbonatite, coexiting, immiscible, Deposit - Dicker Willem Complex
DS2002-1324
2002
Reid, D.L.Reid, D.L., Cooper, A.F.The Dicker Willem carbonatite complex, southern Namibia: review and revision11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 38.NamibiaCarbonatite
DS200812-1186
2007
Reid, D.L.Trumbull, R.B., Reid, D.L., De Beer, C., Van Acken, D., Romer, R.L.Magmatism and continental breakup at the west margin of southern Africa: a geochemical comparison of dolerite dikes from northwestern Namibia and the Western Cape.South African Journal of Geology, Vol. 110, 2-3, Sept. pp. 477-502.Africa, South Africa, NamibiaMagmatism
DS1993-0565
1993
Reid, D.R.Gourley, A.C., Reid, D.R.Substantial compliance in staking mining claims: did Bill 71 codify thestandard?Prospectors and Developers Association of Canada (PDAC) Digest, Vol. 6, No. 30, Summer p. 6, 7, 8, 9CanadaEconomics, Legal policy
DS1993-1291
1993
Reid, G.Reid, G.Overseas exploration by Australian Mining Companies -perspective of CRA exploration Pty. LtdAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 5 October pp. 11-15AustraliaCompany profile, CRA.
DS1989-0455
1989
Reid, I.Frostick, L., Reid, I.Is structure the main control of river drainage and sedimentation inriftsJournal of African Earth Sciences, Vol. 8, No. 2/3/4, pp. 165-182AfricaTectonics, Geomorphology -rivers
DS1994-0813
1994
Reid, I.Jackson, H.R., Reid, I.Crustal thickness variations between Greenland and Ellesmere Island margins detremined from seismic...Canadian Journal of Earth Sciences, Vol. 31, pp. 1407-18.Greenland, Northwest Territories, Ellesmere IslandGeophysics - seismics, Crust
DS1996-1170
1996
Reid, I.Reid, I.Crustal structure across the Nain Makkovik boundary on the continental shelf off Labrador from seismic data.Canadian Journal of Earth Sciences, Vol. 33, No. 3, March pp. 460-471LabradorTectonics, Geophysics -seismic refraction
DS1996-1171
1996
Reid, I.Reid, I.Crustal structure across the Nain- Makkovik boundary on the continental shelf off Labrador from seismic dataCanadian Journal of Earth Sciences, Voll. 33, No. 3, March pp. 460-471.LabradorTectonics, Geophysics -seismics
DS2001-0348
2001
Reid, I.D.Funck, T., Louden, K.E., Reid, I.D.Crustal structure of the Grenville Province in southeastern Labrador from refraction seismic data:Canadian Journal of Earth Science, Vol. 38, No. 10, Oct. pp. 1463-78.Quebec, LabradorCrustal wedge = high velocity lower, Tectonics
DS1860-0810
1893
Reid, J.Reid, J.The Story of South African Diamond FieldsGood Words, P. 613.Africa, South AfricaHistory
DS1989-1259
1989
Reid, J.B. Jr.Reid, J.B. Jr., Steig, E., Bryan, W.B.Major element evolution of basaltic magmas: a comparison of the information in CMAS and ALFE projectionsContributions to Mineralogy and Petrology, Vol. 101, No. 3, pp. 318-325GlobalMagma Geochemistry, Basalt
DS1970-0181
1970
Reid, J.B.JR.Reid, J.B.JR.The Origin of Lherzolite Xenoliths from Salt Lake Crater, Hawaii.Unknown., ASBTRACT.United States, HawaiiBlank
DS1990-1218
1990
Reid, J.C.Reid, J.C.Update: GSMAP and other U.S. Geological Survey programs for earth scienceapplicationsGeobyte, Vol. 5, No. 4, August-September pp. 31-32GlobalComputer, Program -GSMAP (overview)
DS1991-1411
1991
Reid, J.C.Reid, J.C., Mauger, R.L., Weiner, L.S., Maybin, A.H.III.Diamond-lamproite model- proposed explanation for North Carolin a and SouthCarolin a diamondsGeological Society of America Abstracts, Vol. 23, No. 1, February p. 121GlobalLamproite, Diamond genesis
DS1992-0496
1992
Reid, J.E.Fullagar, P.K., Reid, J.E.Conductivity - depth transformations of fixed loop TEM dataExploration Geophysics, Bulletin. Austalian Society of Exploration, Vol. 23, No. 3, September pp. 515-520AustraliaGeophysics, TEM.
DS1992-0497
1992
Reid, J.E.Fullagar, P.K., Reid, J.E.Conductivity -depth transformations of fixed loop TEM dataAustralian Society of Exploration Geophysics, Vol. September pp. 515-520GlobalGeophysics -TEM.
DS2003-1153
2003
Reid, J.L.Reid, J.L.Regional modern alluvium sampling survey of the Kirkland Lake Matachewan regionOntario Geological Survey Open File, No. 6120, pp. 19- 1-9.Ontario, Kirkland LakeGeochemistry - kimberlites mentioned
DS200412-1650
2003
Reid, J.L.Reid, J.L.Regional modern alluvium sampling survey of the Kirkland Lake Matachewan region, northeastern Ontario.Ontario Geological Survey Open File, No. 6120, pp. 19- 1-9.Canada, Ontario, Kirkland LakeGeochemistry - kimberlites mentioned
DS200512-0899
2004
Reid, J.L.Reid, J.L.Regional alluvium sampling survey of the Cobalt Elk Lake area, northeastern Ontario.Ontario Geological Survey Open File, No. 6119, 140p. $ 16.00 M, R. Data 124 CD $20.Canada, OntarioKimberlite indicator mineralogy
DS201906-1281
2019
Reid, K.Chakhmouradian, A., Reid, K.Wekusko Lake dikes ( central Manitoba): long -overdue kimberlites, oddball carbonatites, or "a missing link?"GAC/MAC annual Meeting, 1p. Abstract p. 70.Canada, ManitobaCarbonatite

Abstract: Manitoba, with its 400 000 km2 of exposed Precambrian basement, remains the most conspicuous "white spot" on the map of Canadian kimberlites. The apparent absence of these rocks from the regional geological record seems all the more paradoxical, given the existence of large Phanerozoic kimberlite fields just across the provincial border in eastern Saskatchewan, and abundant evidence of mantle-derived carbonate-rich magmatism (carbonatites and ultramafic lamprophyres) across central Manitoba. Interestingly, rocks of this type were first identified in the Province in 1983 at Wekusko Lake, where they crosscut supracrustal assemblages of the Paleoproterozoic Flin Flon belt, and were tentatively logged as kimberlites. This interpretation, based to a large extent on their high Cr + Ni contents and the presence of indicator minerals in their modal composition, was challenged in subsequent research. Similar rocks have been recognized recently in similar settings south of Wekusko Lake. These discoveries expanded not only the area of known post-Paleoproterozoic mantle magmatism, but also the petrographic and geochemical spectrum of its products. The primary carbonate phase in these rocks is dolomite that shows a variable degree of subsolidus isotopic re-equilibration under CO2-rich conditions. Fluid-rock interaction was also responsible for the replacement of olivine, phlogopite and groundmass perovskite by secondary minerals and deposition of hydrothermal carbonates in fractures, although the relative timing of these processes with respect to dike emplacement is poorly understood at present. Notably, indicator minerals indistinguishable from those in bona fide kimberlites are common in all of the examined dikes. These recent discoveries may hold key to understanding the genetic relations between kimberlites and primitive carbonatites, and have practical implications for heavy-mineral-based diamond exploration.
DS1982-0517
1982
Reid, M.Reid, M., Hart, S.R., Padovani, E.Evolution of the Lower Crust Beneath Kilbourne Hole, New Mexico.Geological Society of America (GSA), Vol. 14, No. 7, P. 597, (abstract.).GlobalKimberlite, Rocky Mountains, Colorado Plateau
DS1985-0558
1985
Reid, M.Reid, M., Hart, S.R.Importance of Sedimentary Protoliths to the Lower Crust Exemplified by the Kilbourne Hole Paragenesis- Sr-neodymium-palladium Isotopegeochemistry.Eos, Vol. 66, No. 46, NOVEMBER 12, P. 1110. (abstract.).United States, Colorado Plateau, New MexicoGeochemistry
DS1986-0628
1986
Reid, M.Padovani, E.R., Wandless, G.A., Reid, M., Hart, S.R.Characterization of the deep crust in an active intracontinental rift:evidence from xenoliths at Kilbourne Hole MaarGeological Society of America, Vol. 18, No. 2, p. 168. AbstractGlobalTectonics
DS1986-0613
1986
Reid, M.R.Nye, C.J., Reid, M.R.Geochemistry of primary and least fractionated lavas from Okmokvolcano, central Aleutians: implications for arc magmagenesisJournal of Geophysical Research, Vol. 91, No. B10, Sept. 10, pp.10, 271- 10, 287GlobalPicrite
DS1987-0609
1987
Reid, M.R.Reid, M.R.Where do rare earth elements reside in the lower crust?Eos, abstractGlobalrare earth elements (REE)., Petrology
DS1989-1260
1989
Reid, M.R.Reid, M.R.Compositional dependence of lead isotopic signatures In the lower crust exhibited by xenoliths from KilbourneHole, New MexicoNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 222. AbstractNew MexicoXenoliths, Geochronology
DS1991-1412
1991
Reid, M.R.Reid, M.R.Imaging magma sources in the southern Rio Grande Rift using deep crustalxenolithsGeological Society of America Abstracts, Rocky Mtn Section, South-Central, Vol. 23, No. 4, April, p. 87. AbstractColorado PlateauKilbourne Hole, Remote sensing
DS1992-0934
1992
Reid, M.R.Leeman, W.P., Sisson, V.B., Reid, M.R.Boron geochemistry of the lower crust: evidence from granulite terranes and deep crustal xenolithsGeochimica et Cosmochimica Acta, Vol. 56, No. 2, February pp. 775-788MantleGeochemistry, Xenoliths
DS1995-1092
1995
Reid, M.R.Leventhal, J.A., Reid, M.R., Montana, A., Holden, P.Mesozoic invasion of crust by Mid Ocean Ridge Basalt (MORB) source asthenopheric magmas. U.S.Cordilleran interiorGeology, Vol. 23, No. 5, May pp. 399-402California, Basin and Range, CordilleraMantle lithosphere, Mid Ocean Ridge Basalt (MORB).
DS1996-1172
1996
Reid, M.R.Reid, M.R., Graham, D.W.Resolving lithospheric and sub lithospheric contributions to helium isotopevariations...Earth and Planetary Science Letters, Vol. 144-1, 2, Oct pp. 213-222.United StatesGeochronology, Lithosphere
DS1996-1173
1996
Reid, M.R.Reid, M.R., Ramos, R.C.Chemical dynamics of enriched mantle in the southwestern United States:thorium isotope evidence.Earth and Planetary Science Letters, Vol. 138, No. 1/4, Feb. 1, pp. 67-82.Nevada, Arizona, ColoradoGeochemistry, geochronology, Mantle geodynamics
DS2003-1568
2003
Reid, M.R.Zou, H.,Reid, M.R., Yongshun Liu, Yupeng Yao, Xisheng Xu, Qicheng FanConstraints on the origin of historic potassic basalts from northeast Chin a by U ThChemical Geology, Vol. 200, 1-2, Oct. 16, pp. 189-201.ChinaPhlogopite garnet bearing peridotite, melting, metasoma
DS200412-2239
2003
Reid, M.R.Zou, H.,Reid, M.R., Yongshun Liu, Yupeng Yao, Xisheng Xu, Qicheng FanConstraints on the origin of historic potassic basalts from northeast Chin a by U Th disequilibrium data.Chemical Geology, Vol. 200, 1-2, Oct. 16, pp. 189-201.ChinaPhlogopite garnet bearing peridotite, melting, metasoma
DS200712-0868
2006
Reid, M.R.Ramos, F.C., Reid, M.R., Sims, K.W.W.Re-evaluating the mantle structure underlying the southwestern US.Geochimica et Cosmochimica Acta, In press availableUnited States, Colorado PlateauGeochronology
DS200812-0950
2008
Reid, M.R.Reid, M.R.How long does it take to supersize an eruption?Elements, Vol. 4, 1, Feb. pp. 23-29.MantleMagmatism
DS201112-0854
2011
Reid, M.R.Reid, M.R., Bouchet, R.A., Blichert-Toft, J.Melting conditions associated with the Colorado Plateau, USA.Goldschmidt Conference 2011, abstract p.1704.United States, Colorado PlateauThermobarometry
DS201212-0581
2012
Reid, M.R.Reid, M.R., Boucher, R.A., Ichert-Toft, J., Levander, A., Liu, K., Miller, M.S., Ramos, F.C.Melting under the Colorado Plateau, USA.Geology, Vol. 40, 5, pp. 387-390.United States, Colorado PlateauMelting
DS201612-2332
2016
Reid, M.R.Rudzitis, S., Reid, M.R., Blichert-Toft, J.On edge melting under the Colorado Plateau margin.Geochemistry, Geophysics, Geosystems: G3, Vol. 17, 10, 1002/ 2016GC006349.United States, Colorado PlateauMelting

Abstract: Asthenosphere beneath the relatively thin lithosphere of the Basin and Range province appears to be juxtaposed in step-like fashion against the Colorado Plateau's thick lithospheric keel. Primary to near-primary basalts are found above this edge, in the San Francisco-Morman Mountain volcanic fields, north central Arizona, western USA. We show that at least two distinct peridotite-dominated mantle end-members contributed to the origin of the basalts. One has paired Nd and Hf isotopic characteristics that cluster near the mantle array and trace element patterns as expected for melts generated in the asthenosphere, possibly in the presence of garnet. The second has isotopic compositions displaced above the ?Hf - ?Nd mantle array which, together with its particular trace element characteristics, indicate contributions from hydrogenous sediments and/or melt (carbonatite or silicate)-related metasomatism. Melt equilibration temperatures obtained from Si- and Mg-thermobarometry are mostly 1340-1425°C and account for the effects of water (assumed to be 2 wt.%) and estimated CO2 (variable). Melt equilibration depths cluster at the inferred location of the lithosphere-asthenosphere boundary at ?70-75 km beneath the southwestern margin of the Colorado Plateau but scatter to somewhat greater values (?100 km). Melt generation may have initiated in or below the garnet-spinel facies transition zone by edge-driven convection and continued as mantle and/or melts upwelled, assimilating and sometimes equilibrating with shallower contaminated mantle, until melts were finally extracted.
DS200612-1148
2005
Reid, N.B.Reid, N.B.Establishment of a vegetation cover on tundra kimberlite mine tailings. 1. A green house study.Restoration Ecology, Vol. 13, 4, pp. 594-601.Canada, Northwest TerritoriesEnvironmental
DS200612-1149
2005
Reid, N.B.Reid, N.B., Naeth, M.A.Establishment of a vegetation cover on tundra kimberlite mine tailings. 2. A field study.Restoration Ecology, Vol. 13, 4, pp. 602-608.Canada, Northwest TerritoriesEnvironmental
DS201112-0855
2002
Reid, N.B.Reid, N.B., Naeth, A.Ekati diamond mine processed kimberlite reclamation.University of British Columbia, Thesis,Canada, Northwest TerritoriesDeposit - Ekati
DS2001-0969
2001
Reid, S.Reid, S.Exploring for diamonds in New South WalesThe AusIMM Bulletin, Aug-Sept.pp. 30-33.AustraliaNews item
DS1940-0090
1944
Reid, W.E.Reid, W.E.Diamond Finds in North AmericaCard Index File Washington, D.c., United StatesBlank
DS201504-0214
2010
Reidel, F.Reidel, F., Dehler, M.Recovery of unliberated diamonds by x-ray transmission sorting. Earlier paper with size range +8mmThe South African Institute of Mining and Metallurgy, pp. 193-201.TechnologyDiamond recovery
DS201609-1739
2010
Reidel, F.Reidel, F., Dehler, M.Recovery of unliberated diamonds by x-ray transmission sorting.The 4th Colloquium on Diamonds - source to use held Gabarone March 1-3, 2010, 8p.TechnologySorting - X-ray DE-XRT

Abstract: In May 2009 a test work programme was carried out at the sorting laboratory of CommodasUltrasort in Germany which was aimed at establishing the efficiency of Xray transmission sorting for the recovery of unliberated diamonds in a size range of +8mm. A PRO Tertiary XRT belt sorter with a working width of 600mm and a belt speed of - 3mJs was used for the test work. Dual energy X-ray transmission sorting is a type of sensor-based sorting which uses an X-ray scanning system, The attenuation of the transmitting X-rays is measured at two different energy levels, Thereby it is possible to eliminate the effect of the particle thickness on the measurement result. The effective measurement results in a classification by elemental order based on the periodic table. Diamonds are mostly composed of Carbon, which has an atomic number of 6. Compared to Silicon with an atomic number of 14, Diamonds show up much lighter on an XRT image than Silica-based gravels (typical DMS sinks material usually has more dense minerals such as Fe, and Mn which shows an even, darker X-ray image than Si). Tests were run with ele.ven Boarl Diamonds in a size range of -15+8mm mixed into 13kg alluvial DMS sinks gravel in a size range of -25+8mm. All liberated Boart Diamonds were recovered at feed rates of 15t/h at average yields of 7.6g per ejected Diamond. In a second test series the Boarl Diamonds were covered in 20% Gypsum by weight and run again at 15t/h. All unliberated Diamonds were recovered at an average yield of 12.2g per ejected Diamond. The paper outlines the test work results in detail.
DS200412-1938
2004
Reidel, M.Strobel, P., Reidel, M., Ristein, J., Ley, L.Surface transfer doping of diamond.Nature, No. 6998, July 22, pp. 439-441.TechnologyDiamond morphology
DS1997-0950
1997
Reidel, M.R.Reidel, M.R., Karato, S.Rheological weakening of subducted slabs due to the persistence of metastable olivine down to 600 km depthFuchs, K. Upper mantle heterogeneities, Nato, Science 17, pp. 325-32.MantleGeophysics - seismology, Subduction, ultra high pressure (UHP)
DS1994-1443
1994
Reif, C.Reif, C.Preliminary geological map of the northern Anialik River volcanic belt and northeast Kangguyak gneiss belt, northwest Territories.Geological Survey of Canada Open file Map., No. 2965, 1: 50, 000 $ 19.75Northwest TerritoriesGeology map, Anialik area
DS1994-1444
1994
Reif, C.Reif, C., Villeneuve, M., Helmstaedt, H.Discovery of an Archean carbonatite bearing alkaline complex in northern Slave Province: tectonic economicsNorthwest Territories 1994 Open House Abstracts, p. 53-54. abstractNorthwest TerritoriesCarbonatite
DS1996-1174
1996
Reif, C.Reif, C., Villeneuve, M.E.Carbonatites and conglomerates Late Archean extension across the SlaveProvince.Geological Association of Canada (GAC) Annual Abstracts, Vol. 21, abstract only p.A79.Northwest TerritoriesCarbonatite, Tectonics
DS1998-1546
1998
Reif, C.Villeneve, M.E., Reif, C.Tectonic setting of 2.6 Ga carbonatites in the Slave Province, northwestCanada.Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 1975-86.Northwest TerritoriesCarbonatite, Tectonics
DS200512-0589
2005
Reigber, X.Kumar, P.R., Kind, W., Hanka, K., Wylegalla, Ch., Reigber, X., Yuan, I., Woelbern, P., GudmundssonThe lithosphere-asthenosphere boundary in the North West Atlantic region.Earth and Planetary Science Letters, Vol. 236, pp. 249-257.EuropeBoundary
DS200612-1439
2006
Reigher, C.Trubitsyn, V., Kaban, M., Mooney, W., Reigher, C., Schwintzer, P.Simulation of active tectonic processes for a convecting mantle with moving continents.Geophysical Journal International, Vol. 164, 3, March pp; 611-623.MantleTectonics
DS1989-0354
1989
Reihl, R.F.Devries, R.C., Reihl, R.F., Tuft, R.E.Fingerprinting diamonds using ion implantationJournal of Mater. Science, Vol. 24, No. 2, pp. 505-509GlobalDiamond morphology, Crystal growth, Gem diamo
DS200612-0385
2006
Reilinger, R.Fadil, A., Vernant, P., McClusky, S., Reilinger, R., Gomez, F., Ben Sari, D., Mourabit, Feigl, BarazangiActive tectonics of the western Mediterranean: geodetic evidence for rollback of a delaminated subcontinental lithospheric slab beneath the Rif Mountains, Morocco.Geology, Vol. 34, 7, July pp. 529-532.Africa, MoroccoTectonics, continental dynamics
DS200612-1150
2006
Reilinger, R.Reilinger, R., McClusky, S., Vernant, P., Lawrence, S., Ergintav, Cakmak, Ozener, Kadirov, Guliev, StepanyanGPS constraints on continental deformation in the Africa Arabia Eurasia continental collision zone and implications for the dynamics of plate interactions.Journal of Geophysical Research, Vol. 111,B5 B05411.AfricaGeodynamics
DS1990-0635
1990
Reilkoff, B.Hajnal, Z., Pandit, B.I., Scott, D., Reilkoff, B.Importance of selecting the most effective processing sequences and relevance of colour displays, analysing the Kapuskasing crustal refelctiondataTerra, Abstracts of Deep Seismic reflection profiling of the Continental, Vol. 2, December abstracts p. 180OntarioTectonics, Kapuskasing Zone
DS1960-0292
1962
Reilly, B.H.Reilly, B.H.Notes on the Geology of the Premier MineAnglo. American Corp., (UNPUB.).South AfricaGeology
DS1998-1225
1998
Reilly, J.F.Reilly, J.F., Muehlberger, W.R., Dickerson, P.W., et al.Looking back at earth.... through EndeavourGeotimes, Vol. 43, No. 11, Nov. pp. 14-20.GlobalRemote sensing, General - brief history ( not specific to diamonds)
DS1998-0656
1998
Reilly, S.Y.Ionov, D.A., Griffin, W.L., Reilly, S.Y.Garnet peridotite xenoliths in alkali basalts from Siberia and Mongolia: acomparison of lithospheric...7th International Kimberlite Conference Abstract, pp. 339-41.Russia, Siberia, Yakutia, Mongolia, BaikalCraton, mantle, xenoliths, Deposit - Udachnaya, VitiM.
DS2001-0800
2001
Reilly, S.Y.Morgan, P.O, Reilly, S.Y.In situ estimates of sub crustal continental lithospheric heat flow.. application to Slave, KaapvaalSlave-Kaapvaal Workshop, Sept. Ottawa, 5p. abstractNorthwest TerritoriesGeothermometry, Craton - Slave
DS200812-0389
2008
Reiman, C.Garrett, R.G., Reiman, C., Smith, D.B., Xie, X.From geochemical prospecting to international geochemical mapping: a historical overview.Geochemistry, Exploration Environment Analysis, Vol. 8, 3-4, pp. 205-217.TechnologyGeochemistry
DS1989-1261
1989
Reimann, C.Reimann, C.Reliability of geochemical analyses: recent experiencesInstitute of Mining and Metallurgy (IMM), Vol. 98, Sect. B., pp. B123-B129GlobalGeochemistry, Analyses - quality controls
DS1998-1226
1998
Reimann, C.Reimann, C.The Kola eco geochemistry project: some lessons for the mineral exploration and processing industrySga News, No. 5, May, pp. 1, 7-12Russia, Kola, Barents regionGeochemistry
DS1998-1227
1998
Reimann, C.Reimann, C., de Caritat, P.Chemical elements in the environmentSpringer, 410p. $ approx. $ 110.0 United StatesGlobalBook - ad, Geochemistry, environment, metals, analytical
DS200812-1084
2008
Reimann, C.Smith, D.B., Reimann, C.Low density geochemical mapping and the robustness of geochemical patterns.Geochemistry, Exploration Environment Analysis, Vol. 8, 3-4, pp. 219-227.TechnologyGeochemistry
DS200512-0379
2005
Reimer, P.J.Guilderson, T.P., Reimer, P.J., Brown, T.A.The boon and the bane of radiocarbon dating.Science, Vol. 307, 5708, Jan. 21, pp. 362-3.Radiocarbon technology - not specific to diamonds
DS1986-0664
1986
Reimer, T.O.Reimer, T.O.Comments on the Europium (Eu) and Thorium (Th) geochemistry of the Archean continental crust of the Kaapval cratonPrecambrian Research, Vol. 31, pp. 275-289South AfricaGeochemistry
DS1995-1794
1995
ReimersSobolev, N.V., Yefimova, E., Reimers, Zakharchenko, MakhinArkhangelsk diamond inclusionsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 558-560.Russia, ArkangelskDiamond inclusions, Deposit -Lomonosov, Pionerskaya, Karpinski, Pomorskaya
DS1997-1074
1997
ReimersSobolev, N.V., Yefimova, Reimers, Zakharchenko, MakhinMineral inclusions in diamonds of the Arkangelsk kimberlite provinceRussian Geology and Geophysics, Vol. 38, No. 2, pp. 379-393.RussiaDiamond inclusions, Deposit - Zolotitsky, Lomonosov, Karpinsky, Pionerskaya
DS201312-0917
2013
Reimers, A.N.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
DS1998-0027
1998
Reimers, L.F.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
DS1998-1228
1998
Reimers, L.F.Reimers, L.F., Pokhilenko, Yefimova, SobolevUltramafic mantle assemblages from Sytykanskaya kimberlite pipe, Yakutia7th. Kimberlite Conference abstract, pp. 730-32.Russia, YakutiaXenoliths, mineral chemistry, Deposit - Sytykanskaya
DS200412-1564
2003
Reimers, L.F.Pokhilenko, N.P., McDonald, J.A., Sobolev, N.V., Reutsky, V.N., Hall, A.E., Logvinova, A.M., Reimers, L.F.Crystalline inclusions and C isotope composition of diamonds from the Snap lake/King Lake kimberlite dyke system: evidence for a8 IKC Program, Session 3, AbstractCanada, Northwest TerritoriesDiamonds - geochronology Deposit - Snap Lake
DS201510-1758
2015
Reimers, L.F.Ashchepkov, I.V., Logvinova, A.M., Reimers, L.F., Ntaflos, T., Spetisus, Z.V., Vladykin, N.V., Downes, H., Yudin, D.S., Travin, A.V., Makovchuk, I.V., Palesskiy, V.S., KhmelNikova, O.S.The Sytykanskaya kimberlite pipe: evidence from deep seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit, Yakutia, Russia.Geoscience Frontiers, Vol. 6, 5, pp. 687-714.Russia, YakutiaDeposit - Sytykanskaya

Abstract: Mantle xenoliths (>150) and concentrates from late autolithic breccia and porphyritic kimberlite from the Sytykanskaya pipe of the Alakit field (Yakutia) were analyzed by EPMA and LAM ICP methods. In P-T-X-f(O2) diagrams minerals from xenoliths show widest variations, the trends P-Fe#-CaO, f(O2) for minerals from porphyric kimberlites are more stepped than for xenocrysts from breccia. Ilmenite PTX points mark moving for protokimberlites from the lithosphere base (7.5 GPa) to pyroxenite lens (5-3.5 GPa) accompanied by Cr increase by AFC and creation of two trends P-Fe#Ol ?10-12% and 13-15%. The Opx-Gar-based mantle geotherm in Alakit field is close to 35 mW/m2 at 65 GPa and 600 °C near Moho was determined. The oxidation state for the megacrystalline ilmenites is lower for the metasomatic associations due to reduction of protokimberlites on peridotites than for uncontaminated varieties at the lithosphere base. Highly inclined linear REE patterns with deep HFSE troughs for the parental melts of clinopyroxene and garnet xenocrysts from breccia were influenced by differentiated protokimberlite. Melts for metasomatic xenoliths reveal less inclined slopes without deep troughs in spider diagrams. Garnets reveal S-shaped REE patterns. The clinopyroxenes from graphite bearing Cr-websterites show inclined and inflected in Gd spectrums with LREE variations due to AFC differentiation. Melts for garnets display less inclined patterns and Ba-Sr troughs but enrichment in Nb-Ta-U. The 40Ar/39Ar ages for micas from the Alakit mantle xenoliths for disseminated phlogopites reveal Proterozoic (1154 Ma) age of metasomatism in early Rodinia mantle. Veined glimmerites with richterite - like amphiboles mark ?1015 Ma plume event in Rodinia mantle. The ?600-550 Ma stage manifests final Rodinia break-up. The last 385 Ma metasomatism is protokimberlite-related.
DS201412-0729
2014
Reiminik, J.R.Reiminik, J.R., Chacko, T., Stern, R.A., Heaman, L.M.Earth's earliest evolved crust generated in an Iceland-like setting.Nature Geoscience, Vol. 7, pp. 529-533.Europe, IcelandMagmatism, upwelling mantle rocks
DS201812-2871
2018
Reimink, J.Reimink, J.From Iceland to Indonesia: understanding the Slave Craton from a modern geological context. Keynote address.2018 Yellowknife Geoscience Forum , 1p. AbstractCanada, Northwest Territoriescraton

Abstract: The formation of continental crust makes Earth unique in our solar system. Yet, despite the importance of the continents for the evolution of the atmosphere, hydrosphere, and life, the mechanism and timing of continental growth throughout Earth history is poorly known. The presently exposed continental crust has an age distribution that would suggest most of the mass grew relatively recently. However, the planet is constantly reworking itself, so age distributions are biased towards young ages. Therefore, geochemists must turn to isotopic tracers to infer the amount of crustal reworking that has occurred to form the presently exposed, or previously eroded, continental crust. The Slave craton, in the NWT, Canada, is in many ways a classic Archean craton. One reason for this is that the Slave craton preserves an extensive history of crust formation, spanning from 4.02 Ga to 2.58 Ga. This talk will focus on the petrology and isotope geochemistry of the oldest preserved rocks in the craton, rocks which form the deformed basement gneiss complex. These rocks preserve the oldest history of the craton and form the substrate upon which later geologic events occurred. Our record of crust formation indicates that the Slave craton basement gneisses record a major change in the mechanism of crust formation, a transition that represents a change from internal reprocessing in a setting analogous to modern Iceland, to crust formation in a setting more similar to modern continental-margin settings. This data is discussed in the context of global paradigms for crust formation throughout Earth history.
DS202003-0334
2019
Reimink, J.Carlson, R.W., Garcon, M., O'Neil, J., Reimink, J.,Rizo, H.The nature of the Earth's crust.Chemical Geology, Vol. 530, 25p. Available pdfMantleArchean geology

Abstract: Recycling of crust into the mantle has left only small remnants at Earth’s surface of crust produced within a billion years of Earth formation. Few, if any, of these ancient crustal rocks represent the first crust that existed on Earth. Understanding the nature of the source materials of these ancient rocks and the mechanism of their formation has been the target of decades of geological and geochemical study. This traditional approach has been expanded recently through the ability to simultaneously obtain U-Pb age and initial Hf isotope data for zircons from many of these ancient, generally polymetamorphic, rocks. The addition of information from the short-lived radiometric systems 146Sm-142Nd and 182Hf-182W allows resolution of some of the ambiguities that have clouded the conclusions derived from the long-lived systems. The most apparent of these is clear documentation that Earth experienced major chemical differentiation events within the first tens to hundreds of millions of years of its formation, and that Earth’s most ancient crustal rocks were derived from these differentiated sources, not from primitive undifferentiated mantle. Eoarchean rocks from the North Atlantic Craton and the Anshan Complex of the North China Craton have sources in an incompatible-element-depleted mantle that dates to 4.44.5 Ga. Hadean/Eoarchean rocks from two localities in Canada show the importance of remelting of Hadean mafic crust to produce Eoarchean felsic crust. The mafic supracrustal rocks of the Nuvvuagittuq Greenstone Belt are a possible example of the Hadean mafic basement that is often called upon to serve as the source for the high-silica rocks that define continental crust. Many, but not all, ancient terranes show a shift in the nature of the sources for crustal rocks, and possibly the physical mechanism of crust production, between 3.03.6 Ga. This transition may reflect the initiation of modern plate tectonics. Eoarchean/Hadean rocks from some terranes, however, also display compositional characteristics expected for convergent margin volcanism suggesting that at least some convergent margin related magmatism began in the Hadean. The persistence of isotopic variability in 142Nd/144Nd into the mid-Archean, and the eventual reduction in that variability by the end of the Archean, provides new information on the efficiency by which mantle convection recombined the products of Hadean silicate-Earth differentiation. The rate of crust production and recycling in the Hadean/Archean, however, is not resolved by these data beyond the observation that extreme isotopic compositions, such as expected for Hadean evolved, continent-like, crust are not observed in the preserved Eoarchean rock record. The lack of correlation between 142Nd/144Nd and 182W/184W variation in Archean rocks suggests that these two systems track different processes; the Sm-Nd system mantle-crust differentiation while Hf-W is dominated by core formation. The major silicate differentiation controlling Sm/Nd fractionation occurred at ?4.4 Ga, possibly as a result of the Moon-forming impact, after the extinction of 182Hf.
DS201610-1903
2016
Reimink, J.R.Reimink, J.R., Davies, J.H.F.L., Chacko, T., Stern, R.A., Heaman, L.M., Sarkar, C., Schaltegger, U., Creaser, R.A., Pearson, D.G.No evidence for Hadean continental crust within Earth's oldest evolved rock unit. (Acasta Gneiss Complex)Nature Geoscience, Vol. 9, pp. 777-780.CanadaHadean crust

Abstract: Due to the acute scarcity of very ancient rocks, the composition of Earth’s embryonic crust during the Hadean eon (>4.0 billion years ago) is a critical unknown in our search to understand how the earliest continents evolved. Whether the Hadean Earth was dominated by mafic-composition crust, similar to today’s oceanic crust1, 2, 3, 4, or included significant amounts of continental crust5, 6, 7, 8 remains an unsolved question that carries major implications for the earliest atmosphere, the origin of life, and the geochemical evolution of the crust-mantle system. Here we present new U-Pb and Hf isotope data on zircons from the only precisely dated Hadean rock unit on Earth—a 4,019.6 ± 1.8?Myr tonalitic gneiss unit in the Acasta Gneiss Complex, Canada. Combined zircon and whole-rock geochemical data from this ancient unit shows no indication of derivation from, or interaction with, older Hadean continental crust. Instead, the data provide the first direct evidence that the oldest known evolved crust on Earth was generated from an older ultramafic or mafic reservoir that probably surfaced the early Earth.
DS201612-2329
2016
Reimink, J.R.Reimink, J.R., Davies, J.H.F.L., Chacko, T., Stern, R.A., Heaman, L.M., Sarkar, C., Schaltegger, U., Creaser, R.A., Pearson, D.G.No evidence for Hadean continental crust within Earth's oldest evolved rock unit.Nature Geoscience, Vol. 9, pp. 777-780.CanadaAcasta Gneiss

Abstract: Due to the acute scarcity of very ancient rocks, the composition of Earth’s embryonic crust during the Hadean eon (>4.0 billion years ago) is a critical unknown in our search to understand how the earliest continents evolved. Whether the Hadean Earth was dominated by mafic-composition crust, similar to today’s oceanic crust1, 2, 3, 4, or included significant amounts of continental crust5, 6, 7, 8 remains an unsolved question that carries major implications for the earliest atmosphere, the origin of life, and the geochemical evolution of the crust-mantle system. Here we present new U-Pb and Hf isotope data on zircons from the only precisely dated Hadean rock unit on Earth—a 4,019.6 ± 1.8?Myr tonalitic gneiss unit in the Acasta Gneiss Complex, Canada. Combined zircon and whole-rock geochemical data from this ancient unit shows no indication of derivation from, or interaction with, older Hadean continental crust. Instead, the data provide the first direct evidence that the oldest known evolved crust on Earth was generated from an older ultramafic or mafic reservoir that probably surfaced the early Earth.
DS201709-2048
2017
Reimink, J.R.Reimink, J.R., Carlson, R.W., Shirey, S.B., Pearson, D.G.Crustal evolution of the Archean Slave craton, NWT.Goldschmidt Conference, abstract 1p.Canada, Northwest Territoriesgeochronology

Abstract: The Slave craton, located in the northwestern portion of the Canadian Shield, contains the oldest known remnant of evolved crust on Earth [1?3] and more extensive suites of granitoid basement gneisses with crystallization ages that nearly span the breadth of the Archean. Portions of these basement gneisses form the Central Slave Basement Complex (CSBC), a belt of exposures recording magmatic events that occurred approximately every 100?150 million years from 3.5?2.7 Ga [4]. When considered with the 4.02 Ga Acasta Gneiss Complex, the good exposure and wide age range of basement gneisses of the Slave craton provide a unique record of the geological processes involved in continent formation. A suite of 3.5?2.7 gyr old Slave craton granitoids collected from a 200 km-long traverse of the CSBC has intermediate to felsic compositions, textures that range from migmatitic gneisses to preservation of primary magmatic features. Preliminary Sm-Nd isotope systematics, as well as zircon U-Pb and Hf isotope data suggest that the granitoids reflect both the products of reworking of Hadean crust, as indicated by the presence of 142Nd deficits in some of the units, but also new additions from the mantle as indicated both in the chemical composition and initial isotopic composition of other rock units. For those samples that derive from remelting of older crustal materials, the initial Hf isotopic composition of zircons are most consistent with a source component that includes Hadean mafic crust. The multiple U-Pb age peaks documented by accessory minerals show a close correspondence with age spectra from the welldocumented mantle lithosphere beneath this region [5] illustrating the coupled evolution of crust and mantle.
DS201905-1073
2019
Reimink, J.R.Reimink, J.R., Pearson, D.G., Shirey, S.B., Carlson, R.W., Ketchum, J.W.F.Onset of new, progressive crustal growth in the central Slave craton at 3.55 Ga.Geochemical Perspective Letters, Vol. 10, pp. 8-13. doi:10.7185/ geochemlet.1907Canada, Northwest Territoriesmagmatism

Abstract: Ancient rock samples are limited, hindering the investigation of the processes operative on the Earth early in its history. Here we present a detailed study of well-exposed crustal remnants in the central Slave craton that formed over a 1 billion year magmatic history. The tonalitic-granodioritic gneisses analysed here are broadly comparable to common suites of rocks found in Archean cratons globally. Zircon Hf isotope data allow us to identify a major change in the way continental crust was formed in this area, with a shift to distinctly positive ?Hf starting at ~3.55 Ga. The crust production processes and spatial distribution of isotopic compositions imply variable interaction with older crust, similar to the relationships seen in modern tectonic settings; specifically, long-lived plate margins. A majority of the Slave craton might have been formed by a similar mechanism.
DS202005-0721
2020
Reimink, J.R.Bauer, A.M., Reimink, J.R., Chacko, T., Foley, B.J., Shirey, S.B., Pearson, D.G.Hafnium isotopes in zircons document the gradual onset of mobile-lid tectonics. ( Pilbara, Zimbabwe, Slave, Singhbhum, Rae, Wyoming, Jack HillsGeochemical Perspectives Letters, Vol. 14, pp. 1-6.GlobalTectonics

Abstract: The tectonic regime of the early Earth has proven enigmatic due to a scarcity of preserved continental crust, yet how early continents were generated is key to deciphering Earth’s evolution. Here we show that a compilation of data from 4.3 to 3.4 Ga igneous and detrital zircons records a secular shift to higher 176Hf/177Hf after ~3.8-3.6 Ga. This globally evident shift indicates that continental crust formation before ~3.8-3.6 Ga largely occurred by internal reworking of long-lived mafic protocrust, whereas later continental crust formation involved extensive input of relatively juvenile magmas, which were produced from rapid remelting of oceanic lithosphere. We propose that this secular shift in the global hafnium isotope record reflects a gradual yet widespread transition from stagnant-lid to mobile-lid tectonics on the early Earth.
DS201312-0686
2008
Reimold, W U.Pati, J.K., Reimold, W U., Koeberl, C., Pati, P.The Dhala structure, Bundelk hand craton, central India - eroded remnant of a large Paleoproterozoic impact structure.Meteorites and Planetary Science, Vol. 40, 8, pp. 1383-1398.IndiaImpact structure
DS201212-0582
2012
Reimold, W.UReimold, W.U, Jourdan, F.Impact! Bolides. Craters and catastrophes.Elements, Vol. 8, 1, Feb, pp. 19-24.GlobalImpact Crater
DS1990-1219
1990
Reimold, W.U.Reimold, W.U., McGee, T., Graup, G.Search for dynamic deformation effects in contact breccias from South african kimberlite pipes21st. Lunar And Planetary Science Conference, March 12-16, Houston, March 16 presentationSouth AfricaAlteration, Kimberlite-breccias
DS1991-0676
1991
Reimold, W.U.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
DS1991-1413
1991
Reimold, W.U.Reimold, W.U., Levin, G.The Vredefort structure, South Africa: a bibliography relating to its geology and evolutionEconomic Geology Research Unit, University of Witwatersrand, Info. Circular No. 242, 24pSouth AfricaBibliography, Vredefort Structure
DS1992-1054
1992
Reimold, W.U.Meyer, F.M., Robb, L.J., Reimold, W.U., de Bruyn, H.D.Sulphur and Iodine type granites during late stage magmatism in the Barberton Mountain Land, southern AfricaEconomic Geology Research Unit, University of of Witwatersrand, Information Circular No. 257, 18pSouth AfricaGranites, Magmatism
DS1992-1267
1992
Reimold, W.U.Reimold, W.U., Colliston, W.P., Wallmach, T.Comment on the nature, distribution and genesis of the coesite and stishovite associated with the pseudotachylite of the Vredefort Dome, SouthAfricaEarth and Planetary Science Letters, Vol. 112, pp. 213-217South AfricaMineralogy, Coesite
DS1994-1206
1994
Reimold, W.U.Minnitt, R.C.A., Reimold, W.U., Colliston, W.P.The geology of the Greenlands greenstone complex and granitoid terranes southeast of Vredefort DomeEconomic Geology Research Unit, Wits, No. 281, 46pSouth AfricaGreenlands greenstone complex
DS1994-1445
1994
Reimold, W.U.Reimold, W.U.Impact cratering - a review with special reference to the economic importance of impact structuresUniversity of Witwatersrand Economic Geology Research Unit, No. 283, 25pSouthern AfricaImpact structures, metallogeny, Review
DS1994-1446
1994
Reimold, W.U.Reimold, W.U.Impact cratering - a review, with special reference to the economic importance of impact structures.Economic Geology Research Unit, U. of Wits, No. 283, 26p.Southern AfricaImpact structures, Diamond deposits p. 14
DS1994-1447
1994
Reimold, W.U.Reimold, W.U., Koeberi, C., Bishop, J.Roter Kam M impact crater, Namibia: geochemistry of basement rocks andbrecciasGeochimica et Cosmochimica Acta, Vol. 58, No. 12, June pp. 2685-1716NamibiaBreccia, Geochemistry
DS1995-0629
1995
Reimold, W.U.Gibson, R.L., Reimold, W.U.Magnetic anomaly near center of Vredefort structure: implications for impact related magnetic signatures:Geology, Vol. 23, No. 12, Dec. pp. 1149-52South AfricaGeophysics -magnetics, Vredefort Structure
DS1995-1557
1995
Reimold, W.U.Reimold, W.U.Pseudotachylite in impact structures -generation by friction melting and stock brecciation? a review -disc-Earth Science Reviews, Vol. 39, No. 3-4, Dec. pp.247-266GlobalImpact structures, Review
DS1995-1558
1995
Reimold, W.U.Reimold, W.U.Pseudotachyite in impact structures - generation by friction melting and shock brecciation? review and discEarth Science Reviews, Vol. 39, pp. 247-265OntarioImpact structures, Review
DS1995-1559
1995
Reimold, W.U.Reimold, W.U.Proceedings of the symposium on the economic significance of metamorphism and fluid movement the Witwatersrand BasinEconomic Geology Research Unit, No. 296, 56pSouth Africametamorphism, Witwatersrand Basin
DS1995-1560
1995
Reimold, W.U.Reimold, W.U., Colliston, W.The Vredefort DomeGeological Society of South Africa, Cent. Geocongress, Guide D1, 45pSouth AfricaKaapvaal Craton, deformation, Witwatersrand Basin, Structure
DS1998-0505
1998
Reimold, W.U.Gibson, R.L., Reimold, W.U., Stevens, G.Thermal metamorphic signature of an impact event in the Vredefort dome, South AfricaGeology, Vol. 26, No. 9, Sept. pp. 787-90South AfricaVredefort Dome, Geothermometry
DS1998-0612
1998
Reimold, W.U.Henkel, H., Reimold, W.U.Integrated geophysical modeling of a giant, complex impact structure:anatomy of the Vredefort structureTectonophysics, Vol. 287, No. 1-4, Mar. 20, pp. 1-20South AfricaStructure, Vredefort
DS1998-1229
1998
Reimold, W.U.Reimold, W.U.Exogenic and endogenic breccias: a discussion of major problematicsEarth Sci. Rev, Vol. 43, pp. 25-47South Africa, FinlandMelt breccia, impact cratering, tectonics, Classification - breccia
DS2001-0270
2001
Reimold, W.U.Dressler, B.O., Reimold, W.U.Terrestrial impact melt rocks and glassesEarth Science Reviews, Vol. 56, No. 1-4, pp. 205-84.GlobalImpact craters, ring basins, Review
DS2002-1325
2002
Reimold, W.U.Reimold, W.U.Major impacts and plate tectonics: a model for the Phanerozoic evolution of the Earth's lithosphere by Neville J. Price.Meteoritics and Planetary Science, Vol. 37, 12, p. 1987.MantleTectonics - book review
DS2003-0426
2003
Reimold, W.U.Friese, A.E.W., Reimold, W.U., Layer, P.W.40 Ar/39 Ar dating of and structural information on tectonite bearing faults in theSouth Africa Journal of Geology, Vol. 106, No. 1, pp. 41-70.South AfricaGeochronology, Geothermometry, tectonics
DS2003-0771
2003
Reimold, W.U.Lana, C., Gibson, R.L., Kisters, A.F., Reimold, W.U.Archean crustal structure of the Kaapvaal Craton, South Africa - evidence from theEarth and Planetary Science Letters, Vol. 206, 1-2, pp. 133-44.South AfricaTectonics
DS2003-1154
2003
Reimold, W.U.Reimold, W.U.Impact cratering comes of ageScience, 5627, June 20, p. 1889.GlobalBlank
DS200412-0483
2004
Reimold, W.U.Dressler, B.O., Reimold, W.U.Order or chaos? Origin and mode of emplacement of breccias in floors of large impact structures.Earth Science Reviews, Vol. 67, 1-2, pp. 1-54.GlobalBreccia
DS200412-0583
2003
Reimold, W.U.Friese, A.E.W., Reimold, W.U., Layer, P.W.40 Ar 39 Ar dating of and structural information on tectonite bearing faults in the Witwatersrand Basin: evidence for multi-stagSouth African Journal of Geology, Vol. 106, no. 1, pp. 41-70.Africa, South AfricaGeochronology Geothermometry, tectonics
DS200412-1082
2004
Reimold, W.U.Lana, C., Reimold, W.U., Gibson, R.L., Koeberl, C., Siegesmund, S.Nature of the Archean midcrust in the core of the Vredfort dome, Central Kaapvaal Craton, South Africa.Geochimica et Cosmochimica Acta, Vol. 68, 3, pp. 623-42.Africa, South AfricaCraton, not specific to diamonds
DS200412-1651
2003
Reimold, W.U.Reimold, W.U.Impact cratering comes of age.Science, 5627, June 20, p. 1889.GlobalImpact - not specific to diamonds
DS200612-0037
2006
Reimold, W.U.Armstrong, R.A., Lana, C., Reimold, W.U., Gibson, R.L.Shrimp zircon age constraints on Mesoarchean crustal development in the Vredefort dome, central Kaapvaal Craton, South Africa.Geological Society of America, Special Paper 405, pp. 233-254.Africa, South AfricaGeochronology
DS200612-1151
2006
Reimold, W.U.Reimold, W.U., Gibson, R.L., editorsProcesses on the Early Earth.Geological Society of America, Processes on the Earth, Special Paper 405,Africa, AustraliaPapers of interest identified by authors
DS200712-0888
2007
Reimold, W.U.Reimold, W.U.Revolutions in the Earth Sciences: continental drift, impact and other catastrophies.South African Journal of Geology, Vol. 110, 1, pp. 1-46.Overview
DS200912-0572
2008
Reimold, W.U.Pati, J.K., Reimold, W.U., Koeberl, C., Pati, P.The Dhala structure, Bundelk hand Craton, central India - eroded remnant of a lare Paleoproterozoic impact structure.Meteorites and Planetary Science, Vol. 43, pp. 1383-1398.IndiaImpact structure
DS201212-0341
2012
Reimold, W.U.Jourdan, F., Reimold, W.U., Deutsch, A.Dating terrestrial impact structures.Elements, Vol. 8, 1, Feb. pp. 49-53.MantleGeochronology
DS201212-0426
2012
Reimold, W.U.Mabolani, S., Cawthorn, R.G., Reimold, W.U.Benfontein -02 kimberlite, northern Cape Province, South Africa.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, South AfricaDeposit - Benfontein-02
DS201312-0937
2013
Reimold, W.U.Vasconcelos, M.A.R., Crosta, A.P., Reimold, W.U., Goes, A.M., Kenkmann, T., Poelchau, M.H.The Serra da Cangalha impact structure, Brazil: geological, stratigraphic and petrographic aspects of a recently confirmed impact structure.Journal of South American Earth Sciences, Vol. 45, pp. 316-330.South America, BrazilMeteorite
DS201412-0731
2014
Reimold, W.U.Reimold, W.U., Koeberl, C.Impact structures in Africa: a review.Journal of African Earth Sciences, Vol. 93, pp. 57-175.AfricaImpacts - review
DS201907-1539
2019
Reimold, W.U.Crosta, A.P., Reimold, W.U., Vasconcelos, M.A.R., Hauser, N., Oliveira, G.J.G.Impact cratering: the South American record - Part 2. Brazil was covered in Part 1. Geochemistry, Vol. 79, pp. 191-220.South Americameteorite

Abstract: In the first part of this review of the impact record of South America, we have presented an up-to-date introduction to impact processes and to the criteria to identify/confirm an impact structure and related deposits, as well as a comprehensive examination of Brazilian impact structures. The current paper complements the previous one, by reviewing the impact record of other countries of South America and providing current information on a number of proposed impact structures. Here, we also review those structures that have already been discarded as not being formed by meteorite impact. In addition, current information on impact-related deposits is presented, focusing on impact glasses and tektites known from this continent, as well as on the rare K-Pg boundary occurrences revealed to date and on reports of possible large airbursts. We expect that this article will not only provide systematic and up-to-date information on the subject, but also encourage members of the South American geoscientific community to be aware of the importance of impact cratering and make use of the criteria and tools to identify impact structures and impact deposits, thus potentially contributing to expansion and improvement of the South American impact record.
DS201812-2794
2018
Reimold, W.V.Crosta, A.P., Reimold, W.V., Vasconcelos, M.A.R., Hauser, N., Oliveira, G.J.G., Maziviero, M.V., Goes, A.M.Impact cratering: the South American record. Part 2.Chemie der Erde, doi.org/10.1016/j ,chemer.2018.09.002 30MBSouth America, Brazilmeteorite

Abstract: In the first part of this review of the impact record of South America, we have presented an up-to-date introduction to impact processes and to the criteria to identify/confirm an impact structure and related deposits, as well as a comprehensive examination of Brazilian impact structures. The current paper complements the previous one, by reviewing the impact record of other countries of South America and providing current information on a number of proposed impact structures. Here, we also review those structures that have already been discarded as not being formed by meteorite impact. In addition, current information on impact-related deposits is presented, focusing on impact glasses and tektites known from this continent, as well as on the rare K-Pg boundary occurrences revealed to date and on reports of possible large airbursts. We expect that this article will not only provide systematic and up-to-date information on the subject, but also encourage members of the South American geoscientific community to be aware of the importance of impact cratering and make use of the criteria and tools to identify impact structures and impact deposits, thus potentially contributing to expansion and improvement of the South American impact record.
DS202001-0035
2019
Reina, G.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.
DS200412-1618
2003
Reinberger, G.Ramsay, W.R.H., Hell, A., Reinberger, G., Pooley, S.The geology, age, near surface features and mineralogy of the Merlin kimberlite field, Northern Territory, Australia.Geological Society of Australia Abstracts, Vol. 70, p. 54. 1p.Australia, Northern TerritoryDeposit overview - Merlin
DS1910-0592
1919
Reinecke, L.Reinecke, L.Undeveloped Mineral Resources of Clinton DistrictThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM), Vol. 22, PP. 341-367.Canada, British ColumbiaBlank
DS1930-0044
1930
Reinecke, L.Wagner, P.A., Reinecke, L.Mineral Deposits of the Union of South AfricaCommonwealth Min. Met. Congress 3rd., 310P.South AfricaKimberley, History, Geology
DS200712-0452
2006
ReinersHu, S., Raza, A., Min, K., Kohn, B.P., Reiners, Ketcham, Wang, GleadowLate Mesozoic and Cenozoic thermotectonic evolution along a transect from the north Chin a craton through the Qinling orogen into the Yangtze craton, central.Tectonics, Vol. 25, 6, TC6009ChinaGeothermometry
DS1995-1561
1995
Reiners, P.W.Reiners, P.W., Nelson, B.K., Ghiorso, M.S.Assimilation of felsic crust by basaltic magma: thermal limits and extents crustal contamination -mantle magmasGeology, Vol. 23, No. 6, June pp. 563-566MantleMagma, Felsic, basalt, contamination, geochemistry
DS1998-1230
1998
Reiners, P.W.Reiners, P.W.Reactive melt transport in the mantle and geochemical signatures of mantle derived magmas.Journal of Petrology, Vol. 39, No. 5, May pp. 1039-62.MantleMagma, Melts
DS1998-1231
1998
Reiners, P.W.Reiners, P.W., Nelson, B.W.Temporal compositional isotopic trends in rejuvenated stage magmas of Kauai and implications for mantle melting.Geochimica et Cosmochimica Acta, Vol. 62, No. 13, pp. 2347-68.Mantle, HawaiiMelting - model
DS2003-1155
2003
Reiners, P.W.Reiners, P.W., Zhou, Z., Ehlers, T.A., Xu, C., Brandon, M.T., Donelick, R.A.Post orogenic evolution of the Dabie Shan, eastern Chin a ( U Th) He and fission trackAmerican Journal of Science, Vol. 303, 6, pp. 489-518.ChinaGeothermometry, UHP
DS200412-1652
2003
Reiners, P.W.Reiners, P.W., Zhou, Z., Ehlers, T.A., Xu, C., Brandon, M.T., Donelick, R.A., Nicolescu, S.Post orogenic evolution of the Dabie Shan, eastern Chin a ( U Th) He and fission track thermochronology.American Journal of Science, Vol. 303, 6, pp. 489-518.ChinaGeothermometry UHP
DS200612-1152
2006
Reiners, P.W.Reiners, P.W., Ehlers, T.A., editorsLow temperature thermochronology: techniques, interpretations and applications.Mineralogical Society of America, Review in Mineralogy and Geochemistry, Vol. 58, 620p. approx. $ 40. business @minsocam.orgGlobalBook - thermochronology
DS201810-2360
2018
Reiners, P.W.Nasdala, L., Corfu, F., Schoene, B., Tapster, S.R., Wall, C.J., Schmitz, M.D., Ovtcharova, M., Schaltegger, U., Kennedy, A.K., Kronz, A., Reiners, P.W., Yang, Y-H., Wu, F-Y., Gain, S.E.M., Griffin, W.L., Szymanowski, D., Chanmuang, C., Ende, N.M., ValleyGZ7 and GZ8 - two zircon reference materials for SIMS U-Pb geochronology.Geostandards and Geoanalytical Research, http://orchid.org/0000-0002-2701-4635 80p.Asia, Sri Lankageochronology

Abstract: Here we document a detailed characterization of two zircon gemstones, GZ7 and GZ8. Both stones had the same mass at 19.2 carats (3.84 g) each; both came from placer deposits in the Ratnapura district, Sri Lanka. The U-Pb data are in both cases concordant within the uncertainties of decay constants and yield weighted mean ²??Pb/²³?U ages (95% confidence uncertainty) of 530.26 Ma ± 0.05 Ma (GZ7) and 543.92 Ma ± 0.06 Ma (GZ8). Neither GZ7 nor GZ8 have been subjected to any gem enhancement by heating. Structure?related parameters correspond well with the calculated alpha doses of 1.48 × 10¹? g?¹ (GZ7) and 2.53 × 10¹? g?¹ (GZ8), respectively, and the (U-Th)/He ages of 438 Ma ± 3 Ma (2s) for GZ7 and 426 Ma ± 9 Ma (2s) for GZ8 are typical of unheated zircon from Sri Lanka. The mean U concentrations are 680 ?g g?¹ (GZ7) and 1305 ?g g?¹ (GZ8). The two zircon samples are proposed as reference materials for SIMS (secondary ion mass spectrometry) U-Pb geochronology. In addition, GZ7 (Ti concentration 25.08 ?g g?¹ ± 0.18 ?g g?¹; 95% confidence uncertainty) may prove useful as reference material for Ti?in?zircon temperature estimates.
DS201412-0938
2014
Reinhard, D.A.Valley, J.W., Cavosie, T., Ushikubo, T., Reinhard, D.A., Lawrence, D.F., Larson, D.J., Clifton, P.H., Kelly, T.F., Wilde, S.A., Moser, D.E., Spicuzza, M.J.Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography.Nature Geoscience, Vol. 7, pp.219-223.MantleGeochronology
DS201509-0434
2015
Reinhard, D.A.Valley, J.W., Reinhard, D.A., Cavosie, A.J., Ushikubo, T., Lawrence, D.F., Larson, D.J., Kelly, T.F., Snoeyenbos, D.R., Strickland, A.Nano- and micro-geochronology in Hadean and Archean zircons by atom-probe tomography and SIMS: new tools for old minerals.American Mineralogist, Vol. 100, pp. 1355-1377.AustraliaGeochronology

Abstract: Atom-probe tomography (APT) and secondary ion mass spectrometry (SIMS) provide complementary in situ element and isotope data in minerals such as zircon. SIMS measures isotope ratios and trace elements from 1–20 ?m spots with excellent accuracy and precision. APT identifies mass/charge and three-dimensional position of individual atoms (±0.3 nm) in 100 nm-scale samples, volumes up to one million times smaller than SIMS. APT data provide unique information for understanding element and isotope distribution; crystallization and thermal history; and mechanisms of mineral reaction and exchange. This atomistic view enables evaluation of the fidelity of geochemical data for zircon because it provides new understanding of radiation damage, and can test for intracrystalline element mobility. Nano-geochronology is one application of APT in which Pb isotope ratios from sub-micrometer domains of zircon provide model ages of crystallization and identify later magmatic and metamorphic reheating.
DS2003-0429
2003
Reinhardt, A.Fuck, Reinhardt, A., Brito Neves, B., Schobbenhaus Filo, C.Search for Rodinia in South America: geological records and problemsGeological Society of America, Annual Meeting Nov. 2-5, Abstracts p.301.BrazilTectonics
DS200412-0589
2003
Reinhardt, A.Fuck, Reinhardt, A., Brito Neves, B., Schobbenhaus Filo, C.Search for Rodinia in South America: geological records and problems.Geological Society of America, Annual Meeting Nov. 2-5, Abstracts p.301.South America, BrazilTectonics
DS200412-0653
2003
Reinhardt, J.Gerya, T.V., Uken, R., Reinhardt, J., Watkeys, M.K., Maresch, W.V., Clarke, B.M.Cold fingers in a hot magma: numerical modeling of country rock diapirs in the Bushveld Complex, South Africa.Geology, Vol. 31, 9, pp. 753-6.Africa, South AfricaDiapirism, magmatism, plumes, subduction zones
DS201511-1878
2015
Reinhardt, J.Schmadicke, E., Gose, J., Reinhardt, J., Will, T.M., Stalder, R.Garnet in cratonic and non-cratonic mantle and lower crustal xenoliths from southern Africa: composition, water in corporation and geodynamic constraints.Precambrian Research, Vol. 270, pp. 285-299.Africa, South Africa, Lesotho, NamibiaKaapvaal craton, Rehoboth Terrane

Abstract: Garnets from kimberlite-hosted mantle and a few xenoliths from the lower crust were investigated for water, major, minor, and trace elements. Xenoliths from the mantle comprise pyroxenite, eclogite, alkremite, and peridotite, and crustal xenoliths are mafic high-pressure granulites. Samples from South Africa, Lesotho, and Namibia comprise two principal settings, Kaapvaal Craton (‘on craton’) and Rehoboth terrane (‘off craton’). The composition of garnet depends on rock type but is unrelated to the setting, except for Ti and Cr. In garnets from ‘off craton’ mantle xenoliths, Ti positively correlates with Cr whereas those from ‘on craton’ samples reveal a negative correlation between both elements. Rare earth element patterns indicative of a metasomatic overprint are observed in garnets from both settings, especially in eclogitic garnet. Water contents in garnet are low and range from <1 to about 40 ppm. No setting-related difference occurs, but a weak correlation between water and rock type exists. Water contents in garnets from eclogite and mafic granulite are lower than those in pyroxenite, alkremite, and peridotite. All garnets are water under-saturated, i.e. they do not contain the maximum amount of water that can be accommodated in the mineral structure. Cratonic and non-cratonic samples also show the same characteristics in the infrared (IR) absorption spectra. An absorption band at 3650 cm-1 is typical for most mantle garnets. Bands at 3520 and 3570 cm-1 are present only in TiO2-rich garnets from the Rehoboth terrane and are ascribed to a Ti-related hydrogen substitution. A number of garnets, especially from the Kaapvaal Craton, contain molecular water in addition to structural water. Molecular water is inhomogeneously distributed at grain scale pointing to local interaction with fluid and to disequilibrium at grain scale. These garnets consistently reveal either submicroscopic hydrous phases or additional IR bands at 3630 and 3610-3600 cm-1 caused by structural water. Both features do not occur in garnets in which molecular water is absent. The observations imply (i) relatively late introduction of fluid, at least in cases where hydrous phases formed, and (ii) a relatively dry environment because only water-deficient garnets are able to incorporate additional structural water. Most importantly, they imply (iii) that the low water contents are primary and not due to water loss during upward transport. This late water influx is not responsible for the metasomatic overprint indicated by garnet REE patterns. The results of this study suggest dry conditions in the lithosphere, including mantle and crustal sections of both the Kaapvaal Craton (‘on craton’) and the Rehoboth terrane (‘off craton’). If the low water contents contributed to the stabilization of the Kaapvaal cratonic root (Peslier et al., 2010) the same should apply to the Rehoboth lithosphere where the same variety of rock types occurs. The extremely low water contents in eclogite relative to pyroxenite may be explained by an oceanic crust origin of the eclogites. Subduction and partial melting would cause depletion of water and incompatible elements. The pyroxenites formed by crystal accumulation in the mantle and did not suffer melt depletion. Such a difference in origin can be reconciled with the low Ti contents in eclogitic garnet and the high Ti contents in pyroxenitic garnet.
DS1997-0821
1997
Reinita, I.M.Moses, T.M., Reinita, I.M., Johnson, M.L., King, J.M.A contribution to understanding the effect of blue fluorescence on the appearance of diamonds.Gems and Gemology, Vol. 33, winter, pp. 244-259.GlobalDiamond fluoresence, Review
DS200512-0751
2004
ReinitzMoses, T.M., Johnson, M.L., Green, B., Blodgett, Cino, Geurts, Gilbertson, hemphill, King, Kornylak, ReinitzA foundation for grading the overall cut quality of round brilliant cut diamonds.Gems & Gemology, Vol. 40, 3, Fall, pp. 202-228.Diamond cutting
DS1991-1414
1991
Reinitz, I.Reinitz, I.Highly conductive blue diamondGems and Gemology, Lab notes, Vol. XXVII, Spring p. 41GlobalDiamond morphology, Nitrogen
DS1992-1386
1992
Reinitz, I.Shigley, J.E., Frutsch, E., Reinitz, I., Moon, M.An update on Sumitomo gem-quantity synthetic diamondsGems and Gemology, Vol. 28, No. 2, Summer pp. 116-122GlobalDiamonds -synthetic, Sumitomo
DS1993-1085
1993
Reinitz, I.Moses, T.M., Reinitz, I., Fritsch, E., Shigley, J.E.Two treated color synthetic red diamonds seen in the tradeGems and Gemology, Notes and New Techniques, Vol. 29, Fall, pp. 182-190.GlobalDiamond morphology, Red diamonds
DS1993-1452
1993
Reinitz, I.Shigley, J.E., Fritsch, E., Reinitz, I.Two near colorless general electric type IIA synthetic diamond crystalsGems and Gemology, Notes and New Techniques, Vol. 29, Fall, pp. 191-196.GlobalDiamond morphology, Synthetic diamonds
DS1998-0610
1998
Reinitz, I.M.Hemphill, T.S., Reinitz, I.M., Johnson, M.L., ShigleyModeling the appearance of the round brilliant cut diamond: an analysis ofbrilliance.Gems and Gemology, Fall pp. 158-183.GlobalDiamond cutting
DS1999-0098
1999
Reinitz, I.M.Buerki, P.R., Reinitz, I.M., Mulhmeister, S., Elen, S.Observation of the H2 defect in gem quality type Ia diamondGems and Gemology, Precis of a paper, Vol. 35. summer, p. 172.GlobalDiamond - absorption
DS2000-0812
2000
Reinitz, I.M.Reinitz, I.M., Buerki, P.R., Shigley, J.E., McClureIdentification of HPHT treated yellow to green diamonds. the saturated neon green colour is not only..Gems and Gemology, Vol. 36, No. 2, Summer, pp. 128-37.United States, Russia, SwedenDiamond - GE, Novatek, treated, colour
DS2001-0970
2001
Reinitz, I.M.Reinitz, I.M., Johnson, Hemphill, Gilbertson et. al.Modeling the appearance of the round brilliant cut diamond: an analysis of fire and more about brilliance.Gems and Gemology, Vol. 37, Fall, pp. 174-97.GlobalDiamond - cutting, Brilliance
DS201312-0307
2011
Reinitz, I.M.Geurts, R.H., Reinitz, I.M., Blodgett, T., Gilbertson, A.M.GIA's symmetry grading boundaries for round brilliant cut diamonds.Gems & Gemology, Vol. 47, winter pp. 286-295.TechnologyDiamond cutting
DS2002-0380
2002
Reinke, M.Diepenbroek, M., Grobe, H., Reinke, M., Schindler, U., SchlitzerPANGEA - an information system for environmental sciencesComputers and Geosciences, Vol. 28, 10, pp.1201-10.GlobalComputers - programs
DS200712-0084
2006
ReinsonBlowes, D.,Moncur, M., Smith, L., Sego, D., Klassen, Neuner, Gravie, Gould, ReinsonMining in the continuous permafrost: construction and instrumentation of two large scale waste rock piles.34th Yellowknife Geoscience Forum, p. 6. abstractCanada, Northwest TerritoriesMining - Diavik
DS200612-1153
2006
Reinson, J.Reinson, J.Diavik diamond mine - Dewey's fault hydrologic investigations.CIM Conference and Exhibition, Vancouver - Creating Value with Values, List of talks CIM Magazine, Feb. p. 78.Canada, Northwest TerritoriesMining - Diavik
DS200712-0889
2006
Reinson, J.R.Reinson, J.R.Defining a suitable level of site characterization - case history on the influence of an undetected highly permeable geologic structure on inflows to the A15434th Yellowknife Geoscience Forum, p. 47-48. abstractCanada, Northwest TerritoriesDiavik - open pit mining
DS1960-0734
1966
Reis, B.Reis, B.Consideration on the Application of Geophysical Prospecting methods to the Search for Kimberlites in the Northeast of Lunda, Angola.Angola Serv. Geol. Min. Bol., No. 14, PP. 49-60.Angola, Central AfricaKimberlite, Geophysics
DS1970-0393
1971
Reis, B.Reis, B.Contribuicao de Aeromagnetica Para E Determinacao de Estruturas Profundas E Sua Importancia Na Descoberta de Coerenciasquimberliticas.I Congreso Hispano-luso-americano, Impresa Iberica, Madred G, No. 1, SECT. 6, PP. 345-397.Angola, Central AfricaKimberlite, Geophysics
DS1970-0394
1971
Reis, B.Reis, B.The Use of Aeromagnetometry in the Determination of Deep Seated Structure and its Importance to Kimberlite Exploration.Serv. Geol. Min. (angola) Bol., No. 23, PP. 11-20.Angola, Central Africa, ZaireGeophysics, Calonda Conglomerate
DS1970-0588
1972
Reis, B.Reis, B.Preliminary Note on the Distribution and Tectonic Control Of Kimberlites in Angola.International Geological Congress 24TH., Vol. 4, PP. 276-281.Angola, West AfricaGeology, Tectonics
DS1980-0288
1980
Reis, B.Reis, B., Ires de barros.Sur Quelques Kimberlites de L'angolaProceedings of the 26th International Geological Congress, Proceedings Vol. 3, P. 996. (abstract.)Angola, West AfricaGeology
DS1981-0346
1981
Reis, B.Reis, B., Monforte, A.Preliminary note on the western massif of Camuttue, Lunda, SOURCE[ Bol. da Soc. Geol. de Portugal, (in Portugese).Bol. da Soc. Geol. de Portugal, (in Portugese)., Vol. 22, pp. 327-336Angola, Central AfricaAlluvial Placers
DS1950-0498
1959
Reis, E.Reis, E.Os Grandes Diamantes BrasileirosRio De Janeiro: Dnpm, Div. Geol. Min. Bol., No. 191, 65P.BrazilKimberlite, Kimberley, Janlib, Diamond, History
DS201803-0447
2017
Reis, N.Fraga, L.M., Cordani, U., Reis, N., Nadeau, S., Camara Maurer, V.U Pb shrimp and La ICPMS new dat a for different A type granites of the Orocaima igneous belt, central Guyana shield, northern Amazonian craton. ( Project Geology of the Guiana Shield)Anais Do 15 Simposio Geologia da Amazonia, Belem , Dec. 5p. Abstract pdfSouth America, Guianacraton

Abstract: The Orocaima Igneous Belt (OIB) is a huge plutono-volcanic belt at the central part of Guiana Shield, consisting mainly of 1.99-1.96 Ga volcano-plutonic rocks with high-K calc-alkaline, A-type and shosho-nitic geochemical signatures. Three A-type granitic bodies from the central part of the OIB have been dated using U-Pb SHRIMP and LA-ICPMS methods. A 1985±11 Ma age was calculated for the Macucal Mountain Granite of the Saracura Suite (Brazil) and ages of 1977±3.9 Ma and 1975±5 were calculated for the alkaline riebeckite granites respectively of the Lontra (Brazil) and Makarapan (Guyana) bodies. These ages are in the same range of those reported for the Aricamã A-type granitoids and the results indicate that different A-type magmatism took place in the 1.993-1.975 Ma interval along the OIB, coeval to high-K calc-alkaline and shoshonitic magmatism. This scenario fits well to a post-collisional setting.
DS2003-1233
2003
Reis, N.J.Schneider Santos, J.O., Potter, P.E., Reis, N.J., Hartmann, L.A., Fletcher, I.R.Age, source and regional stratigraphy of the Roriama Supergroup and Roraima likeGeological Society of America Bulletin, Vol. 115, 3, pp. 331-48.Guyana Shield, Pacaraima PlateauGeochronology, Amazon Craton, zircon
DS200412-1762
2003
Reis, N.J.Schneider Santos, J.O., Potter, P.E., Reis, N.J., Hartmann, L.A., Fletcher, I.R., McNaughton, N.J.Age, source and regional stratigraphy of the Roriama Supergroup and Roraima like outliers in northern South America based on U PGeological Society of America Bulletin, Vol. 115, 3, pp. 331-48.South America, GuyanaGeochronology, Amazon Craton, zircon
DS201707-1360
2017
Reis, N.J.Reis, N.J., Nadeau, S., Fraga, L.M., Menezes Betiollo, L., Telma Lins Faraco, M., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil Guyana border in the Guiana shield, northern Amazonian craton - results of the Brazil Guyana geology and geodiversity mapping project.Brazil Journal of Geology, Vol. 47, 1, pp. 43-57.South America, Brazil, Guyanacraton

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil?Guyana border zone allowed reviewing and in? tegrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú?Ireng River between Mount Roraima (the tri? ple?border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro?Burro Group of Guyana.
DS201810-2371
2018
Reis, N.J.Reis, N.J., Nadeau, S., Fraga, L.M., Betiollo, L.M., Faraco, M.T.L., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil-Guyana border in the Guiana shield, northern Amazonian craton- results of the Brazil-Guyana geology and geodiversity mapping project.Brazilian Journal of Geology, Vol. 47, 1, pp. 43-57.South America, Brazil, Guyanacraton

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil?Guyana border zone allowed reviewing and in? tegrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú?Ireng River between Mount Roraima (the tri? ple?border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro?Burro Group of Guyana.
DS201901-0084
2019
Reis, N.J.Teixeira, W., Reis, N.J., Bettencourt, J.S., Klein, E.L., Oliveira, D.C.Intraplate Proterozoic magmatism in the Amazonian craton reviewed: geochronology, crustal tectonics and global barcode matches.Dyke Swarms of the World: a modern perspective Ed. Srivastava et al. Springer , Chapter pp. 111-154. availableSouth America, Guiana, Brazilcraton

Abstract: We review geochronological data including U-Pb baddelyite ages of Proterozoic mafic dyke swarms and sills of the Amazonian Craton, as well as their geochemical character and geological settings, in order to arrive at an integrated tectonic interpretation. The information together with the characteristics of coeval volcanic-plutonic suites indicates a cyclicity of the mafic-felsic activity through time and space. At least four LIP/SLIP events are apparent, and each one appears to accompany the stepwise accretionary crustal growth of Amazonia. The oldest two, the Orocaima (1.98-1.96 Ga) and Uatumã (c. 1.89-1.87 Ga) SLIPs, comprise calc-alkaline I-type and subordinate A-type plutonic and volcanic rocks. Synchronous mafic intraplate activity occurs across the Guiana and Central-Brazil Shields. These two events may be caused by interaction between subduction-related processes and mantle plumes with synchronous lithosphere extension during the two time periods. The Avanavero (1.79 Ga) LIP event mostly consists of mafic dykes and sills which are intrusive into the Roraima platform cover, in the Guiana Shield. They show tholeiitic chemistry and similarities with E-MORB and subcontinental lithospheric mantle-derived basalts, whereas the REE pattern suggests affinity with intraplate settings. The age of the Avanavero rocks is identical to the Crepori Diabase, located ca. 1800 km away to the south (Central-Brazil Shield). The youngest LIP event (1.11 Ga), the Rincón del Tigre-Huanchaca, has the Rio Perdido Suite as a component in the Rio Apa Terrane, which is ca. 300 km away from the Rincón del Tigre Complex, located in the SW portion of the Amazonian Craton. Furthermore, the Central-Brazil and Guiana Shields boasts widespread intraplate mafic activity, highlighted by the Mata-Matá (1.57 Ga), Salto do Céu (1.44 Ga) and Nova Floresta (1.22 Ga) mafic sills and the Cachoeira Seca Troctolite (1.19 Ga). Contemporaneous A-type, rapakivi granites with roughly similar ages also occur elsewhere. These particular episodes are extension specific steps of the Mesoproterozoic Amazonia, and the quite large distribution is consistent with LIP events. In a broader perspective, the intermittent Proterozoic intracratonic activity has a barcode that matches LIP/SLIP events in Columbia and Rodinia.
DS201904-0772
2017
Reis, N.J.Reis, N.J., Nadeau, S., Fraga, L.M., Menezes Betiollo, L., Telma Lins, Faraco, M., Reece, J., Lachhman, D., Ault, R.Stratigraphy of the Roraima Supergroup along the Brazil-Guyana border in the Guiana shield, northern Amazonian craton - results of the Brazil Guyana geology and geodiversity mapping project.Brazilian Journal of Geology, Vol. 41, 1, pp. 43-57.South America, Brazil, GuyanaGuiana shield

Abstract: The Geological and Geodiversity Mapping binational program along the Brazil-Guyana border zone allowed reviewing and integrating the stratigraphy and nomenclature of the Roraima Supergroup along the Pakaraima Sedimentary Block present in northeastern Brazil and western Guyana. The area mapped corresponds to a buffer zone of approximately 25 km in width on both sides of the border, of a region extending along the Maú-Ireng River between Mount Roraima (the triple-border region) and Mutum Village in Brazil and Monkey Mountain in Guyana. The south border of the Roraima basin is overlain exclusively by effusive and volcaniclastic rocks of the Surumu Group of Brazil and its correlated equivalent the Burro-Burro Group of Guyana.
DS201911-2570
2019
Reis, N.J.Teixeira, W., Reis, N.J., Bettencourt, J.S., Oliveira, D.C.Intraplate Proterozoic magmatism in the Amazonian craton reviewed: geochronology, crustal tectonics and global barcode matches.Dyke swarms of the world: a modern perspective., 10.1007/978-981-13-1666-1_4 South America, Guiana, Brazilmagmatism

Abstract: We review geochronological data including U-Pb baddelyite ages of Proterozoic mafic dyke swarms and sills of the Amazonian Craton, as well as their geochemical character and geological settings, in order to arrive at an integrated tectonic interpretation. The information together with the characteristics of coeval volcanic-plutonic suites indicates a cyclicity of the mafic-felsic activity through time and space. At least four LIP/SLIP events are apparent, and each one appears to accompany the stepwise accretionary crustal growth of Amazonia. The oldest two, the Orocaima (1.98-1.96 Ga) and Uatumã (c. 1.89-1.87 Ga) SLIPs, comprise calc-alkaline I-type and subordinate A-type plutonic and volcanic rocks. Synchronous mafic intraplate activity occurs across the Guiana and Central-Brazil Shields. These two events may be caused by interaction between subduction-related processes and mantle plumes with synchronous lithosphere extension during the two time periods. The Avanavero (1.79 Ga) LIP event mostly consists of mafic dykes and sills which are intrusive into the Roraima platform cover, in the Guiana Shield. They show tholeiitic chemistry and similarities with E-MORB and subcontinental lithospheric mantle-derived basalts, whereas the REE pattern suggests affinity with intraplate settings. The age of the Avanavero rocks is identical to the Crepori Diabase, located ca. 1800 km away to the south (Central-Brazil Shield). The youngest LIP event (1.11 Ga), the Rincón del Tigre-Huanchaca, has the Rio Perdido Suite as a component in the Rio Apa Terrane, which is ca. 300 km away from the Rincón del Tigre Complex, located in the SW portion of the Amazonian Craton. Furthermore, the Central-Brazil and Guiana Shields boasts widespread intraplate mafic activity, highlighted by the Mata-Matá (1.57 Ga), Salto do Céu (1.44 Ga) and Nova Floresta (1.22 Ga) mafic sills and the Cachoeira Seca Troctolite (1.19 Ga). Contemporaneous A-type, rapakivi granites with roughly similar ages also occur elsewhere. These particular episodes are extension specific steps of the Mesoproterozoic Amazonia, and the quite large distribution is consistent with LIP events. In a broader perspective, the intermittent Proterozoic intracratonic activity has a barcode that matches LIP/SLIP events in Columbia and Rodinia.
DS202108-1307
2021
Reis, N.J.Reis, N.J., Cordani, U., Schobbenhaus, C., Maurer, V.C.New U-Pb age to the Pedra Pintada suite at the type-locality Roraima, Guiana Shield.CPRM, 1p. Abstract pdfSouth America, Venezuelacraton
DS201910-2294
2019
Reis Jalowitski, T.L.Reis Jalowitski, T.L., Grings Cadeno, D., Veira Conceicao, R., Dalla Costa, M.M., Carvalho, A.M.G., Noqueira Neto, J.D.A.Are Juina diamonds, Super Deep diamonds?Goldschmidt2019, 1p. AbstractSouth America, Brazildeposit - Juina

Abstract: Super Deep Diamonds (SDD) are known to form at depths between ~300 and ~1000 km in the Earth’s mantle [1]. These diamonds as well as their minerals, melts and fluid inclusions are rare natural materials from deep Earth. The aim of this study is to indentify and characterize mineral inclusions in diamonds from Juína, Mato Grosso, Brazil, and hence classify them as SDD (or not). Twelve diamonds from four different mining sites of Juína were selected according to their inclusions using an Estereo Microscope. The main diamond features were based on crystallographic faces, shape, degrees of resportion, crystal state and intergrowing [2]. Diamond samples are transparent, colorless and present octahedro, octahedro-tetrahexahedral and tetrahexahedral habits. Some diamonds show trigons with positive and negative relief, and hexagons with negative relief. Four diamonds are heavily resorbed and were classified as "unknowing habits", as their shapes are distorced and fragmented. Moreover, three samples show abrasion on the vertices of the quartenary axes, and the others have distinct degrees of resorption. Some crystals present intergorwth, such as contact twins (macle) in {111} or aggregates. All diamonds have mineral inclusions of different colors. Most inclusions are black and could be carbon spots, oxides or even silicates, such as olivine. Other inclusions are yellow to red, which might indicate garnet. In addition, blue inclusions were observed, and could be sulphides. The next steps consists of Fourier Transform Infrared (FTIR) to determine diamond nitrogen impurities, and Micro-Raman spectroscopy and X-Ray Diffraction analyses using Synchrotron radiation to determine in situ the chemical composition of mineral inclusions.
DS1998-1369
1998
Reis NetoSoares, P.C., Rostirolla, Reis NetoPre-Gondwana continental fragments: amalgamation and mineralization in southeastern South America.Journal of African Earth Sciences, Vol. 27, 1A, p. 187. AbstractSouth AmericaTectonics
DS201112-1081
2010
Reis Neto, J.M.Vasconcellos, E.M.G., Lopes, A.P., Fischer, G., Marchese, C., Reis Neto, J.M.Microtomografia de raios x applicada ao estudo de inclusoes em diamantes.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 44-45.South America, BrazilTomography - inclusions
DS1996-0796
1996
Reisberg, L.Kumar, N., Reisberg, L., Zindler, A.A major and trace element and strontium, neodynium and osmium isotopic study of thick pyroxenite Beni BouseraGeochimica et Cosmochimica Acta, Vol. 60, No. 8, April pp. 1429-1444.MoroccoGeochronology, Deposit -Beni Bousera
DS2000-0760
2000
Reisberg, L.Peslier, A.H., Reisberg, L., Francis, D.Rhenium- Osmium (Re-Os) constraints on harzburgite and lherzolite formation in the lithospheric mantle: a study xenolithsGeochimica et Cosmochimica Acta, Vol. 64, No. 17, Sept. 1, pp. 3061-Northwest Territories, Western Canada, AlbertaXenoliths, Geochronology
DS2003-0840
2003
Reisberg, L.Lorand, J.P., Reisberg, L., Bedini, R.M.Platinum group elements and melt percolation processes in Sidamo spinel peridotiteChemical Geology, Vol. 196, 1-4, pp. 57-75.EthiopiaXenoliths
DS2003-0841
2003
Reisberg, L.Lorand, J-P., Reisberg, L., Bedini, R.M.Platinum group elements and melt percolation processes in Sidamo spinel peridotiteChemical Geology, Vol. 196, 1-4, May 15, pp. 57-75.EthiopiaTectonics, Gregory Rift
DS2003-0933
2003
Reisberg, L.Meisel, T., Reisberg, L., Moser, J., Carignan, J., Melcher, F., Brugmann, G.Re Os systematics of UB N, a serpentinized peridotite reference materialChemical Geology, Vol. 201, 3-4, Nov. 14, pp.161-179.FranceGeochronology, metamorphosed lherzolite
DS200412-1174
2003
Reisberg, L.Lorand, J.P., Reisberg, L., Bedini, R.M.Platinum group elements and melt percolation processes in Sidamo spinel peridotite xenoliths Ethiopia, East African Rift.Chemical Geology, Vol. 196, 1-4, pp. 57-75.Africa, EthiopiaXenoliths
DS200412-1175
2003
Reisberg, L.Lorand, J-P., Reisberg, L., Bedini, R.M.Platinum group elements and melt percolation processes in Sidamo spinel peridotite xenoliths, Ethiopia, East African Rift.Chemical Geology, Vol. 196, 1-4, May 15, pp. 57-75.Africa, EthiopiaTectonics, Gregory Rift
DS200412-1293
2003
Reisberg, L.Meisel, T., Reisberg, L., Moser, J., Carignan, J., Melcher, F., Brugmann, G.Re Os systematics of UB N, a serpentinized peridotite reference material.Chemical Geology, Vol. 201, 3-4, Nov. 14, pp.161-179.Europe, FranceGeochronology, metamorphosed lherzolite
DS200412-1653
2004
Reisberg, L.Reisberg, L., Lorand, J.P., Bedini, R.M.Reliability of Os model ages in pervasively metasomatized continental mantle lithosphere: case study Sidamo spinel peridotite xeChemical Geology, Vol. 208, 1-4, pp. 119-140.Africa, EthiopiaGeochronology, metasomatism
DS200612-1154
2005
Reisberg, L.Reisberg, L., Zhi, X., Lorand, J.P., Wagner, C., Peng, Z., Zimmermann, C.Re Os S systematics of spinel peridotite xenoliths from east central China: evidence for contrasting effects of melt percolation.Earth and Planetary Science Letters, Vol. 239, 3-4, pp. 286-308.ChinaGeochronology
DS200912-0862
2009
Reisberg, L.Zheng, L.,Zhi, X., Reisberg, L.Re-Os systematics of the Raobazhai peridotite massifs from the Dabie orgenic zone, eastern China.Chemical Geology, Vol. 268, 1-2, Oct. 20, pp. 1-14.ChinaUHP
DS201112-0134
2011
Reisberg, L.Callegaro, S., Marzoli, A., Bertrand, H., Reisberg, L., Chiaradia, M., Beelieni, G.Geochemistry of eastern North American CAMP diabase dykes.Goldschmidt Conference 2011, abstract p.614.United States, AppalachiaCentral Atlantic Province .... basaltic
DS201112-0649
2011
Reisberg, L.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
DS201112-1073
2011
Reisberg, L.Van der Meer, Q.H.A., Klaver, M., Reisberg, L., Davidheiser, B., Davies, G.R.The age and origin of the Limpopo sub-continental lithospheric mantle.Goldschmidt Conference 2011, abstract p.2064.Africa, South AfricaVenetia
DS201212-0744
2012
Reisberg, L.Van der Meer, Q.H.A., Klaver, M., Reisberg, L., Davies, G.R.The age and origin of the Limpopo ( South Africa) subcontinental lithospheric mantle.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, South AfricaGeochronology
DS201602-0221
2016
Reisberg, L.Luguet, A., Reisberg, L.Highly siderophile element and 187 Os signatures in non-cratonic basalt hosted peridotite xenoliths: unravelling the origin and evolution of the Post-Archean lithospheric mantle.Reviews in Mineralogy and Geochemistry, Vol. 81, pp. 305-367.MantleHSE elements
DS201709-2068
2017
Reisberg, L.van der Meer, Q.H.A., Klaver, M., Reisberg, L., Riches, A.J.V., Davies, G.R.Preservation of an Archaean whole rock Re-Os isochron for the Venetia lithospheric mantle: evidence for rapid crustal recycling and lithospheric stabilization at 3.3 Ga.Geochimica et Cosmochimica Acta, in press available, 22p.Africa, South Africadeposit - Venetia

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.
DS201710-2273
2017
Reisberg, L.Van der Meer, Q., Klaver, M., Reisberg, L., Riches, A. J.V., Davies, G.R.Preservation of an Archean whole rock Re-Os isochron for the Venetia lithospheric mantle: evidence for rapid crustal recycling and lithosphere stabilization at 3.3 Ga.Geochimica et Cosmochimica Acta, Vol. 216, pp. 242-263.Africa, South Africadeposit - Venetia
DS1989-1262
1989
Reisberg, L.C.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
DS1991-1415
1991
Reisberg, L.C.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
DS200712-0574
2007
ReischmannKostopoulos, D., Chatzitheodoridis, E., Cornelius, Baltatzis, ReischmannEnvironment of diamond formation in UHPM rocks from the Greek Rhodope: a Raman study of inclusions in zircon.Plates, Plumes, and Paradigms, 1p. abstract p. A517.Europe, GreeceUHP
DS1995-1562
1995
Reischmann, T.Reischmann, T., Brugmann, G.E., Jochum, K.P., Todt, W.A.Trace element and isotopic composition of baddeleyiteMineralogy and Petrology, Vol. 53, No. 1-3, pp. 155-164.GlobalMineralogy, Baddeleyite
DS2001-0049
2001
Reischmann, T.Arndt, N., Bruzak, G., Reischmann, T.The oldest continental and oceanic plateaus: geochemistry of basalts and komatiites Pilbara CratonGeological Society of America Special Paper, Special Paper. 352, pp. 359-88.AustraliaBasalts, Craton
DS200712-0169
2007
Reischmann, T.Chatzitheodoridis, E., Kostopoulos, D., Lyon, I., Henkel, T., Cornelius, N., Baltatzis, E., Reischmann, T.Elemental distributions in zircons from Diamondiferous UHPM rocks from the Greek Rhodope: a TOF-SIMS study.Plates, Plumes, and Paradigms, 1p. abstract p. A163.Europe, GreeceUHP
DS2003-1243
2003
Reiss, N.J.Scneider Santos, J. Orestes, Potter, P.E., Reiss, N.J., Hartmann, L.A., FletcherAge, source and regional stratigraphy of the Roraima Supergroup and Roraima likeGeological Society of America Bulletin, Vol. 115, 3, pp. 331-348.Guyana Shield, South America, BrazilAmazon Craton, baddeleyite, diamond, geochronology
DS201611-2126
2016
Reissner, C.Nasdala, L., Dobrzhinetskaya, L.F., Korsakov, A.V., Massone, J-J., Reissner, C.UHP phases versus preparation materials - be cautious when using micro-raman spectroscopy.European Mineralogical Conference held Sept. 11-15, Italy, p. 219. abstract 1p.TechnologyRaman Spectroscopy
DS201612-2323
2016
Reissner, C.Nasdala, L., Steger, S., Reissner, C.Raman study of diamond based abrasives, and possible artefacts in detecting UHP microdiamond.Lithos, Vol. 265, pp. 317-327.TechnologyUHP - microdiamond

Abstract: Raman spectral characteristics of a range of diamond-based abrasives (powders and sprays) and drilling and cutting tools, originating from preparation laboratories worldwide, are presented. Some abrasives show strong broadening of the main diamond band [FWHM (full width at half band-maximum) > 5 cm? 1] accompanied by strong band-downshift (View the MathML source?˜ = 1316-1330 cm? 1). Others are characterised by moderate band broadening (FWHM = 1.8-5 cm? 1) at rather regular band position (View the MathML source?˜ = 1331-1333 cm? 1). In addition we found that a "fresh" abrasive and its used analogue may in some cases show vast differences in their Raman spectra. The Raman parameters of diamond-based abrasives overlap widely with Raman parameters of UHP (ultra-high pressure) microdiamond. It is hence impossible to assign diamond detected in a geological specimen to either an introduced artefact or a genuine UHP relict, from the Raman spectrum alone. Raman is an excellent technique for the detection of minute amounts of diamond; however it does not provide conclusive evidence for the identification of UHP microdiamond. The latter requires thorough verification, for instance by optical microscopy or, if doubts cannot be dispelled, transmission electron microscopy.
DS1950-0499
1959
Reitan, P.H.Reitan, P.H., Geul, J.J.G.On the Formation of the Carbonate Bearing Ultrabasic Rock At Kviteberg Lyngen, Northern Norway.Norges Geol. Unders. Skr., No. 205, PP. 111-127.Norway, ScandinaviaPetrogenesis
DS1970-0182
1970
Reitan, P.H.Reitan, P.H., Szekely, J., Foster, B.P.Material Emplacement Models for Dikes Extending to the MantlEos, Vol. 51, P. 447. (abstract.).United States, Appalachia, New YorkBlank
DS1970-0511
1972
Reitan, P.H.Foster, B.P., Reitan, P.H.Kimberlite Dike Emplacement in the Central Finger Lakes Region.Geological Society of America (GSA), Vol. 4, P. 17. (abstract.).United States, Kansas, Central States, WilsonBlank
DS1970-0978
1974
Reitan, P.H.Reitan, P.H.Eu Anomaly in KimberliteGeology, Vol. 2, No. 2, FEBRUARY P. 72. (abstract.)United StatesRare Earth Elements (ree), Geochemistry
DS201312-0739
2013
Reiter, B.Reiter, B.Directors' duties in Canada. 5th editionCCH Wolters Kluwer, in press available early 2013CanadaGovernance
DS201312-0740
2012
Reiter, B.Reiter, B.Director's duties in Canada, 5th. Edition now 1045p. (ist ed. Had 350p. Times have changed!!!)CCH Canada 1 800-268-4522, 5th ed. Approx $ 170. plus taxCanadaDirectors duties - extensive chapters
DS2002-1193
2002
Reiter, F.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
DS1983-0533
1983
Reiter, M.Reiter, M., Clarkson, G.Geothermal Studies in the San Juan Basin and the Four Corners Area of the Colorado Plateau. Ii Steady State Models of The Thermal Source San Juan Volcanic Field.Tectonophysics, Vol. 91, PP. 253-269.GlobalRocky Mountains, Geophysics
DS1983-0534
1983
Reiter, M.Reiter, M., Mansure, A.J.Geothermal Studies in the San Juan Basin and the Four Corners Area of the Colorado Plateau. I. Terrestrial Heat Flow Measurements.Tectonophysics, Vol. 91, PP. 233-251.GlobalRocky Mountians, Geophysics
DS1991-1163
1991
Reiter, M.Minier, J., Reiter, M.Heat flow on the southern Colorado PlateauTectonophysics, Vol. 200, pp. 51-86Colorado Plateau, WyomingHeat flow, Jemez zone, crust
DS1992-1268
1992
Reiter, M.Reiter, M., Barroll, M.W., Cather, S.M.Rotational buoyancy tectonics and models of simple half graben formationJournal of Geophysical Research, Vol. 97, No. B6, June 10, pp. 8917-8926GlobalSubduction, Graben model
DS201412-0732
2014
Reiter, M.Reiter, M.Heat flow dat a in the Four Corners area suggest Neogene crustal warming resulting from partial lithosphere replacement in the Colorado Plateau interior, southwest USA.Geological Society of America Bulletin, Vol. 126, pp. 1084-1092.United States, Colorado PlateauGeothermometry
DS202102-0213
2021
Reitsky, V.N.Palyanov, Y.N., Borzdov, Y.M., Sokol, A.G., Btaaleva, Y.V., Kupriyanov, I.N., Reitsky, V.N., Wiedenbeck, M., Sobolev, N.V.Diamond formation in an electric field under deep Earth conditions.Science Advances, Vol. 7, 4, eabb4644 doi: 10.1126/ sciadv.abb4644 28p. PdfMantlegeophysics

Abstract: Most natural diamonds are formed in Earth’s lithospheric mantle; however, the exact mechanisms behind their genesis remain debated. Given the occurrence of electrochemical processes in Earth’s mantle and the high electrical conductivity of mantle melts and fluids, we have developed a model whereby localized electric fields play a central role in diamond formation. Here, we experimentally demonstrate a diamond crystallization mechanism that operates under lithospheric mantle pressure-temperature conditions (6.3 and 7.5 gigapascals; 1300° to 1600°C) through the action of an electric potential applied across carbonate or carbonate-silicate melts. In this process, the carbonate-rich melt acts as both the carbon source and the crystallization medium for diamond, which forms in assemblage with mantle minerals near the cathode. Our results clearly demonstrate that electric fields should be considered a key additional factor influencing diamond crystallization, mantle mineral-forming processes, carbon isotope fractionation, and the global carbon cycle.
DS200812-0484
2008
Reitter, E.Hopp, J., Trieloff, M., Brey, G.P., Woodland, A.B., Simon, N.S.C., Wijbrans, J.R., Siebel, W., Reitter, E.40 Ar 39 Ar ages of phlogopite in mantle xenoliths from South African kimberlites: evidence for metasomatic mantle impregnation during Kilbaran orogenic cycle.Lithos, Vol. 106, no. 3-4, pp. 351-364.Africa, South Africa, LesothoDeposit - Bultfontein, Letseng, Liqhobong
DS1980-0289
1980
Reitz, B.Reitz, B., Cullers, R.L.Petrogenesis of Kimberlites, Riley County, KansasGeological Society of America (GSA), Vol. 12, No. 1, P. 16, (abstract.).KansasKimberlite, Central States
DS1970-0183
1970
Reitzel, J.S.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
DS1992-1281
1992
Rejou-Michel, A.Robert, F., Rejou-Michel, A., Javoy, M.Oxygen isotope homogeneity of the earth: new evidenceEarth and Planetary Science Letters, Vol. 108, No. 1/3. January pp. 1-10GlobalEarth, Geochronology
DS1993-1292
1993
Rekdal, T.Rekdal, T., Doornbos, D.J.A modified form of diffraction tomography to image boundary structuresGeophysics, Vol. 58, No. 8, August pp. 1136-1147GlobalGeophysics -seismics, Tomography, Mantle
DS1993-1293
1993
Rekdal, T.Rekdal, T., Doornbos, D.J.A modified form of diffraction tomography to image boundary structuresGeophysics, Vol. 58, No. 8, August pp. 1136-1147.GlobalMantle, Tectonics, boundary structure
DS201412-0733
2014
Rekha, S.Rekha, S., Bhattacharya, A.Paleo/Mesoproterozoic tectonism in the northern fringe of the western Dharwar craton ( India): its relevance to Gondwanaland and Columbia supercontinent reconstructions.Tectonics, Vol. 33, 4, pp. 552-580.IndiaSupercontinents
DS1989-1263
1989
Rekharskiy, V.I.Rekharskiy, V.I., Dikov, Yu.P., Mukhin, L.M., Gerasimov, M.V.Geostages and endogenic ore materialInternational Geology Review, Vol. 30, No. 11, Nov. pp. 1151-1161. Database # 17981RussiaMantle-crust relationship, Metallogeny
DS200712-0348
2006
Rekhi, S.Garai, J., Haggerty, S.E., Rekhi, S., Chance, M.Infrared absorption investigations confirm the extraterrestrial origin of carbonado diamonds.The Astrophysical Journal, Vol. 653, Dec. 20, pp. L153-L156.TechnologyCarbonado diamonds
DS200912-0243
2009
Rekhi, S.Garat, J., Haggerty, S.E., Rekhi, S., Chance, M.Infrared absorption investigations confirm the extraterrestrial origin of carbonado diamonds.The Astrophysical Journal, Vol. 653, L153-156.Africa, Central African Republic, South America, BrazilCarbonado
DS2000-0384
2000
RelfHanmer, S., Aspler, L., Sandeman, Davis, Peterson, RelfHenik - Kaminak - Tavani supracrustal belt. late Archean oceanic crust and island arc remnants....Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 4p. abstract.Northwest Territories, ChurchillProterozoic reworking, Structure
DS2000-0605
2000
RelfMacLachlan, K., Hanmer, S., Berman, W.J., Ryan, RelfComplex, protracted, Proterozoic reworking Western Churchill Province: the craton that wouldn't grow up.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000, 4p. abstractWestern Canada, Northwest Territories, SaskatchewanTectonics - craton, Geothermometry
DS1990-0838
1990
Relf, C.King, J.E., Davis, W.J., Relf, C., Van Nostrand, T.Geology of the Contwyoto Lake Nose Lake area, central Slave ProvinceGeological Survey of Canada (GSC) Paper, No. 1990-1C, pp. 177-87.Northwest TerritoriesGeology
DS1997-0469
1997
Relf, C.Hammer, S., Relf, C.Western Churchill Province: recent results, fresh perspectives, newinitiatives.Geological Survey of Canada Forum 1997 abstracts, p. 4. AbstractSaskatchewanCraton, Structure
DS1997-0897
1997
Relf, C.Pell, J.A., Stanley, M., Relf, C.Archean carbonatite bearing alkaline complexes, Slave structural northwest Territories.Geological Association of Canada (GAC) Abstracts, POSTER.Northwest TerritoriesCarbonatite, Slave Structural province
DS1997-1213
1997
Relf, C.Villeneuve, M.E., Relf, C.Temporal coincidence of Wide spread Archean carbonatite intrusion and granite magmatism in the Slave Province.Geological Association of Canada (GAC) Abstracts, Northwest TerritoriesCarbonatite, Magmatism
DS2000-0813
2000
Relf, C.Relf, C., Hanmer, S.A summary of post Archean magmatic and tectonothermal events western Churchill Province: to mantle and back.28th. Yellowknife Geoscience Forum, p.65-6.abstractNorthwest TerritoriesMagmatism, Tectonics
DS2001-0971
2001
Relf, C.Relf, C.Geologic overview of the Slave ProvinceGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p. 125.abstract.Northwest TerritoriesTectonics, Mantle xenoliths
DS2003-0098
2003
Relf, C.Bennett, V., Jackson, V., Rivers, T., Tubrett, M., Relf, C.Mapping lower crustal age domains utilizing LAM ICP MS U-Pb dating of inherited31st Yellowknife Geoscience Forum, p. 5. (abst.NunavutGeochronology, Tectonics, SRT
DS200412-0133
2003
Relf, C.Bennett, V., Jackson, V., Rivers, T., Tubrett, M., Relf, C.Mapping lower crustal age domains utilizing LAM ICP MS U-Pb dating of inherited zircons: a new diamond exploration tool?31st Yellowknife Geoscience Forum, p. 5. (abst.Canada, NunavutGeochronology, Tectonics, SRT
DS200412-0782
2004
Relf, C.Hanmer, S., Sandeman, H.A., Davis, W.J., Aspler, L.B., Rainbird, R.H., Ryan, J.J., Relf, C., Peterson, T.D.Geology and Neoarchean tectonic setting of the Central Hearne supracrustal belt, Western Churchill Province, Nunavut, Canada.Precambrian Research, Vol. 134, 1-2, pp. 63-83.Canada, NunavutTectonics - not specific to diamonds
DS200512-0669
2005
Relf, C.Maclachlan, K., Davis, W.J., Relf, C.Paleoproterozoic reworking of an Archean thrust fault in the Hearne Domain, Western Churchill Province: U Pb geochronological constraints.Canadian Journal of Earth Sciences, Vol. 42, 7, July pp. 1-18.Canada, Northwest Territories, NunavutGeotectonics
DS200612-0121
2006
Relf, C.Bennett, V., Jackson, V.A., Rivers, T., Relf, C., Horan, P., Tubrett, M.Geology and U Pb geochronology of the Neoarchean Snare River terrane: tracking evolving tectonic regimes and crustal growth mechanisms.Canadian Journal of Earth Sciences, Vol. 42, 6, pp. 895-934.Canada, Northwest TerritoriesGeochronology
DS200612-1155
2006
Relinger, R.Relinger, R., McClusky, S., Vernant, P., Lawrence, S.GPS constraints on continental deformation in the Africa-Arabia-Eurasia continental collision zone and implications for the dynamics of plate interactions.Journal of Geophysical Research, Vol. 111, B5, May 31, B05411AfricaTectonics
DS1960-0088
1960
Relph, R.E.Relph, R.E.Petrological Report on Rocks from the Delegate District Snowy Mountains Progress Report No. 15, Wellesley and Bendock Military Sheets.New South Wales Report Department of Mines, No. 5, 135P.Australia, New South WalesKimberlite, Snodgrass
DS2002-1326
2002
Relvas, J.M.R.S.Relvas, 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
DS201412-0020
2014
Remirs, L.Ashchepkov, I., Remirs, L., Ntaflos, T., Vladykin, N., Logvinova, A., Travin, A., Yudin, D., Karpenko, K., Makovchuk, I., Palessky, S., Salikhov, R.Evolution of mantle column of pipe Sytykanskaya, Yakutia kimberlite.Goldschmidt Conference 2014, 1p. AbstractRussia, YakutiaDeposit - Sytykanskaya
DS200512-0900
2005
Remizov, D.N.Reverdatto, V.V., Selyatisky, A.Yu., Remizov, D.N., Khlestov, V.V.Geochemical distinctions between mantle and crustal high/ultrahigh pressure peridotites and pyroxenites.Doklady Earth Sciences, Vol. 400, 1, pp. 72-76.MantleUHP
DS200512-0901
2004
Remizov, D.N.Reverdatto, V.V., Selyatitsky, A.Y., Remizov, D.N., Khlestov, V.V.Geochemical distinctions between mantle and crustal high/ultrahigh pressure peridotites and pyroxenites.Doklady Earth Sciences, Vol. 400, 1, pp. 72-76.MantleGeochemistry
DS1984-0406
1984
Remizov, V.I.Kharkiv, A.D., Zinchuk, N.N., Remizov, V.I.Distinctive Features of the Secondary Mineralization in Kimberlite Rocks of Guinea.Geologii i Geofiziki, No. 11, (299), NOVEMBER PP. 64-West Africa, GuineaMineralogy
DS1984-0407
1984
Remizov, V.I.Kharkiv, A.D., Zinchuk, N.N., Remizov, V.I.Some Distinctive Features of Secondary Mineralization in Kimberlites of Guinea.Soviet Geology And Geophysics, Vol. 25, No. 11, PP. 64-71.West Africa, GuineaMineralogy
DS1984-0408
1984
Remizov, V.I.Kharkiv, A.D.., Zinchuk, N.N., Remizov, V.I.Some distinctive features of secondary mineralization in kimberlites ofGuineaSoviet Geology and Geophysics, Vol. 25, No. 11, pp. 64-71GuineaWeathering
DS1998-0729
1998
Remley, D.Keller, R.A., Remley, D., Snyder, Taylor, SobolevMantle xenoliths from the Obnazhennaya kimberlite, Yakutia7th International Kimberlite Conference Abstract, pp. 402-4.Russia, YakutiaXenoliths, Deposit - Obnazhennaya
DS1998-1366
1998
Remley, D.Snyder, G.A., Keller, R.A., Taylor, L.A., Remley, D.The origin of ultramafic (Group A) eclogites: neodymium and Strontium isotopic evidence from the Obnazhennaya kimberlite.7th International Kimberlite Conference Abstract, pp. 823-5.Russia, YakutiaEclogite xenoliths, Deposit - Obnazhennaya
DS1999-0589
1999
Remley, D.A.Remley, D.A.Petrogenesis of eclogite xenoliths from the Obnazhennaya kimberlite pipe, Yakutia, Russia. #2University of Tennessee, Knoxville, Msc. Thesis copy not in hand - could tryRussia, YakutiaXenoliths, Deposit - Obnazhennaya
DS1999-0590
1999
Remley, D.A.Remley, D.A.Petrogenesis of eclogite xenoliths from the Obnazhennaya kimberlite pipe, Yakutia, Russia. #1University of Tennessee, Knoxville, Msc. Thesis, 78p.Russia, YakutiaXenoliths, Deposit - Obnazhennaya
DS2003-1365
2003
Remley, D.A.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
DS200412-1974
2003
Remley, D.A.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
DS1989-1264
1989
Remote SensingRemote SensingSpecial issue on the Earth Observing System (EOS). Introduction: Eos dataGeoscience and Remote Sensing, Vol. 27, No. 2, March pp. 109-116. Issue pp. 109-242United StatesGeoscience and Remote Sensing, EOS data
DS1997-0951
1997
Rempe. N.T.Rempe. N.T.Waste disposal in underground Mines - a technology partnership to protectthe environmentMining Engineering, Vol. 49, No. 3, March pp. 49-52United States, New MexicoMining, Waste disposal, environment
DS1975-0634
1977
Rempel, G.G.Surkov, V.S., Isaev, G.A., Rempel, G.G.Transient Processes Method (tpm) in Prospecting for Deep Conductive Ore Bodies in Siberia.Soviet Geology GEOPHYS., Vol. 18, No. 7, PP. 6-12.RussiaKimberlite, Geophysics
DS1975-1198
1979
Rempel, G.G.Rempel, G.G.Structural characteristics of the placement of kimberlites and coppernickel ores on the Siberian PlatformRussian Geology and Geophysics, Vol. 20, No. 10, pp. 61-68.Russia, SiberiaTectonics - Structure, Discontinuity, Platform
DS1996-1175
1996
Rempel, H.Rempel, H.World energy - a changing sceneNonrenewable Resources, Vol. 5, No. 3, pp. 137-139GlobalEconomics, Energy overview
DS201412-0734
2014
Remshardt, W.J.Remshardt, W.J., Shurgot, C., Coolen, R., Clipperton, K., Chisholm, V.Kennady Lake Lue T'E Halye ( Fish-out).2014 Yellowknife Geoscience Forum, p. 66, abstractCanada, Northwest TerritoriesFish removal - permit
DS200812-0988
2008
Remus, M.V.D.Saalmann, K., Remus, M.V.D., Hartmann, L.A.Neoproterozoic magmatic arc assembly in the southern Brazilian Shield constraints for a plate tectonic model for the Brasilliano Orogeny.Geotectonic Research, Vol. 95, suppl. 1 pp. 41-59.South America, BrazilMagmatism, Tectonics
DS201112-0895
2011
Remus, M.V.D.Saalmann, K., Gerdes, A., Lahaye, Y., Hartmann, L.A., Remus, M.V.D., Laufer, A.Multiple accretion at the eastern margin of the Rio de la Plat a craton: the prolonged Brasiliano orogeny in southernmost Brazil.International Journal of Earth Sciences, Vol. 100, 2, pp. 355-378.South America, BrazilCraton, not specific to diamonds
DS201707-1312
2017
Remus, M.V.D.Cerva-Alves, T., Remus, M.V.D., Dani, N., Basei, M.A.S.Integrated field, mineralogical and geochemical characteristics of Cacapava do sul alvikite and beforsite intrusions: a new Ediacaran carbonatite complex in southernmost Brazil.Ore Geology Reviews, in press availableSouth America, Brazilcarbonatite

Abstract: The integrated evaluation of soil geochemistry, aerogammaspectrometry (eTh), geological and structural mapping associated with the description of boreholes and outcrops in the Caçapava do Sul region, southernmost Brazil, led to the discovery of two carbonatite bodies. They are located near the eastern and southeastern border of Caçapava do Sul Granite and intrude the Passo Feio Complex. The carbonatite system is composed of early pink-colored alvikite followed by late white beforsite dikes. The carbonatites are tabular bodies concordant with the deformed host rocks. Petrographic and scanning electron microscopy show that the alvikites are dominantly composed of calcite with subordinate apatite, magnetite, ilmenite, biotite, baddeleyite, zircon, rutile, pyrochlore-like and rare earth element minerals. Beforsite is composed of dolomite and has the same minor and accessory minerals as the alvikite. U-Pb zircon geochronology via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was performed on a beforsite sample, yielding a 603.2 ± 4.5 Ma crystallization age. The carbonatite was emplaced an Ediacaran post-collisional environment with transpressive tectonism and volcanic activity marked by shoshonitic affinity.
DS202002-0177
2019
Remus, M.V.D.de Mamam Anzolin H., Dani, N., Remus, M.V.D., da Rocha Ribeiro, R., Nunes, A.R., Ruppel, K.M.V.Apatite multi-generations in the Tres Estradas carbonatite, southern Brazil: physical and chemistry meaning and implications to phosphate ore quality. Brazil Journal of Geology ( www.scielo.br) ENG, 17p. PdfSouth America, Brazildeposit - Tres Estradas

Abstract: Carbonatites were recently discovered in Southern Brazil, which increased the interest to evaluate the economic potential of these uncommon rocks, especially the Três Estradas Carbonatite. Carbonates are the dominant minerals of fresh rock followed by apatite, but the weathering process makes apatite abundant. We focused on apatite from the carbonatite using conventional petrography and electronic microscopy associated with microprobe, micro-Raman and Fourier-transform infrared spectroscopy. Results demonstrate the existence of four types. The primary type is associated with the rock crystallization and the subsequent three others are associated with weathering processes. The alteration mechanism was favorable for initial carbonate leaching and subsequent increase of phosphate with late precipitation of three new apatite generations. The deduced model involves long exposure during polycyclic climate changes, intercalating periods of warm dry with humid climate. The apatite types differ chemically and morphologically and have distinctive characteristics that are suitable to be used to differentiate them. These properties should be considered in future planes of industrial processes to transform apatite into single superphosphate, a basic input for fertilizer production.
DS200812-0637
2008
Remusat, L.Le Guillou, C., Rouzaud, J.N., Bourot-Denise, M., Remusat, L., Jambion, A.Laboratory shock synthesized diamond vs carbons from a differentiated meteorite.Goldschmidt Conference 2008, Abstract p.A532.Urelilite
DS201705-0812
2017
Remusat, L.Bureau, H., Remusat, L., Esteve, I., Pinti, D., Cartigny, P.Isotopic characterization of diamond growth in fluids.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 19147 AbstractTechnologyDiamond inclusions

Abstract: Trapping inclusions in diamonds has been used as a diagnostic to constrain diamond growth media (e.g. Navon et al., 1994; Weiss et al., 2015) in the Earth's upper mantle. Experimental works now generate inclusion-bearing diamonds from seeds in mixtures of carbonates, graphite, and silicates in the presence of excess of pure water or saline fluids (H2O-NaCl) and investigate in more details the conditions of natural diamond growth (Bureau et al., 2012; 2016). Experiments were carried at conditions compatible with the Earth's geotherm between 6-7 GPa (1300-1675°C) in multi-anvil presses at the Bayerisches Geoinstitut, Bayreuth from a few hours two a few days. Results show that within the timescale of the experiments diamond growth occurs on seeds if water and alkali-bearing carbonates are present. We show that water promotes fast diamond growth, which is favorable to the formation of inclusions. Thin sections of a few diamond seeds containing exposed inclusions were prepared using a Focus Ion Beam (about 2 to 5 µm thickness). These sections were deposited on silicon wafers and gold coated for micron-scale determination of the delta 13C isotopic compositions using the NanoSIMS 50 installed at the Muséum National d'Histoire Naturelle, Paris. Carbon isotope measurement with NanoSIMS were calibrated against a natural Ia and a synthetic IIa diamond used for diamond anvil cells, whose compositions were determined by gas-source mass spectrometry at IPGP at 3.6±0.1‰ and -20.9±0.1‰, respectively (Pinti et al., 2016). All the starting materials used for the experiments were also characterized for their delta 13C by the same technique at GEOTOP, Montréal. The isotopic composition of the new diamond grown areas were measured close to the inclusions. They exhibit a different isotopic signature than that of the starting seeds (starting diamond composition: -29.6 to -30.4±1.4‰). The new diamond signatures are falling into the range of signatures of the starting carbonates used for the experiments (- 4.8±0.1 to -16.2±0.1‰) when they are far away from the composition of the starting graphite (-26.4±0.1‰). This shows that the carbon source for diamond growth must be the carbonates present either as CO32- ions dissolved in the melt or as carbon dioxide species CO2 in the aqueous fluid and that diamond growth occurred from carbonate reduction rather that from graphite dissolved in the melt. We suggest that the presence of small discrete or isolated volumes of water-carbonate-rich fluids are necessary to grow inclusion-bearing peridotitic, eclogitic, fibrous, cloudy and coated diamonds, and may also be involved in the growth of ultrahigh pressure metamorphic diamonds.
DS201709-1966
2017
Remusat, L.Bureau, H., Remusat, L., Esteve, I., Pinti, L., Cartigny, P.The carbon source for lithospheric diamonds.Goldschmidt Conference, abstract 1p.Mantlecarbon

Abstract: Trapping inclusions in diamonds during growth experiments is used as a diagnostic to constrain natural diamond formation conditions in the Earth’s lithosphere. Isotopic signature of the new diamond grown areas close to those inclusions is also useful to identify the carbon source for the diamonds. In this study experiments were carried at conditions compatible with the Earth’s geotherm between 6-7 GPa (1300-1675°C) in multi-anvil presses from a few hours to a few days. Carbon-bearing starting materials are powders of carbonates and graphite. Results show that within the timescale of the experiments diamond growth occurs on preexisting seeds if water and alkali-bearing carbonates are present. The ?13C isotopic composition of the new diamond grown areas measured close to the inclusions show a different isotopic signature than that of the starting seeds (-29.6 to - 30.4±1.4‰). The new diamond carbon signatures are falling into the range of signatures of the starting carbonates used for the experiments (-4.8±0.1 to -16.2±0.1‰) but far away from the composition of the starting graphite (-26.4±0.1‰). This suggests that the carbon source for diamond growth at the conditions of the lithosphere must be the carbonates present either as CO3 2- ions dissolved in the melt or as carbon dioxide in the aqueous fluid. It is concluded that diamond growth occurred from carbonate reduction rather that from graphite dissolution in the melt.
DS201807-1481
2018
Remusat, L.Bureau, H., Remusat, L., Esteve, I., Pinti, D.L., Cartigney, P.The growth of lithospheric diamonds. ( inclusions and carbon isotope fractionation)Science Advances, Vol. 4, 6, doi:10.1126/ sciadv.aat1602Mantlediamond morphology

Abstract: Natural diamonds contain mineral and fluid inclusions that record diamond growth conditions. Replicating the growth of inclusion-bearing diamonds in a laboratory is therefore a novel diagnostic tool to constrain the conditions of diamond formation in Earth’s lithosphere. By determining the carbon isotopic fractionation during diamond growth in fluids or melts, our laboratory experiments revealed that lithospheric monocrystalline and fibrous and coated diamonds grow similarly from redox reactions at isotopic equilibrium in water and carbonate-rich fluids or melts, and not from native carbon. These new results explain why most of the lithospheric diamonds are characterized by a common carbon isotopic fingerprint, inherited from their common parent fluids and not from the mantle assemblage.
DS1996-0690
1996
RenJishun, RenThe continental tectonics of ChinaJournal of Southeast Asian Earth Sciences, Vol. 13, No. 3/5, pp. 197-204ChinaTectonics
DS202111-1788
2021
Ren, J.Sun, K., Zhao, Z., Zhang, L., Qiu, L., Liu, X., He, S., Ren, J., Ye, L., Cui, Y.Geochronology, petrography and Sr-Nd-Hf isotopes of Mbalizi carbonatite, southwestern Tanzania.Journal of African Sciences, Vol. 184, 104308, 12p. PdfAfrica, Tanzaniadeposit - Mbalizi

Abstract: The Mbalizi carbonatite is located in the middle of the Paleoproterozoic Ubendian Mobile Belt and the western branch of East Africa Rift, southwestern Tanzania. Calcite, dolomite, phlogopite, pyrochlore and apatite are found in the sample. Mineral chemistry studies have shown that the carbonatite phlogopite is linked to mantle-derived magmatism. The apatite is fluorapatite, means they are of magmatic origin. The analyses on two crystals of pyrochlore show high concentrations of Nb2O5, and therefore the Nb-oxide is classified as pyrochlore subspecies. Three types of zircon have been obtained from the Mbalizi carbonatite, including xenocrysts zircon, igneous zircon and metamorphic zircon. Zircon in-situ LA-ICP-MS U-Pb dating in this contribution indicates that the Mbalizi carbonatite was crystallized at ca. 116.0 ± 1.8 Ma. The ?Hf(t) values of igneous zircon ranging from ?13.9 to +5.7, indicates that the carbonatite parental magma was originated from the sub-continental lithospheric mantle, and evolves toward HIMU and EM. The whole-rock Sr-Nd isotopic data suggest more contribution of the HIMU and EM? material. We propose that the complex evolutionary history of the Ubendian Mobile Belt has stored the subduction oceanic crust which has the EM? and HIMU components, forming the compositional heterogeneity mantle beneath the Ubendian Mobile Belt. At 116.0 ± 1.8 Ma, with the extension stress field, deep faults cause the pressure reduction, resulting in reactive of the upwelling of the HIMU and EM? components. This provides the metamorphic conditions to induce the isotopic resetting and may result in large scatter of initial 176Hf/177Hf ratios of carbonatite melts.
DS201212-0232
2012
Ren, L.Geng, Y., Du, L., Ren, L.Growth and reworking of the early Precambrian continental crust in the North Chin a Craton: constraints from zircon Hf isotopes.Gondwana Research, Vol. 21, 2-3, pp. 517-529.ChinaMelting
DS201112-0822
2011
Ren, M.Prejeant, K., Perez, M., White, J.C., Ren, M.Geology of the Elliot County kimberlite, Kentucky.Geological Society of America, Annual Meeting, Minneapolis, Oct. 9-12, abstractUnited States, KentuckyKimberlite petrology
DS201112-0823
2011
Ren, M.Prejeant-Dickerson, K., Perez, M., White, J.C., Lierman, R.T., Ren, M.Mineral geochemistry of the Elliot County kimberlite, Kentucky.Geological Society of America, Annual Meeting, Minneapolis, Oct. 9-12, abstractUnited States, KentuckyKimberlite dikes
DS201707-1307
2017
Ren, M.Bell, A.S., Shearer, C., Burger, P., Ren, M., Newville, M., Lanzirotti, A.Quantifying and correcting the effects of anisotropy in Xanes measurements of chromium valence in olivine: implications for a new olivine oxybarometer.American Mineralogist, Vol. 102, pp. 1165-1172.Technologyolivine

Abstract: Chromium valence ratios in igneous olivine may hold a wealth of redox information about the melts from which they crystallized. It has been experimentally shown that the Cr2+/?Cr of olivine varies systematically with fO2, therefore measurements of Cr valence in olivine could be employed as a quantitative oxybarometer. In situ synchrotron ?-XANES analyses of Cr valence ratios of individual olivine phenocrysts in thin section have the potential to unlock this stored magmatic redox information on a fine spatial scale. However, there are still obstacles to obtaining accurate XANES measurements of cation valence in crystalline materials, as the results from these measurements can be compromised by anisotropic absorption effects related to the crystallographic orientation of the sample. Improving the accuracy of XANES measurements of Cr valence ratios in olivine by calibrating an anisotropy correction is a vital step in developing Cr valence measurements in olivine as a rigorous oxybarometer. To accomplish this goal, we have used an integrated approach that combined experiments, electron backscatter diffraction analysis, and XANES measurements in olivine to systematically examine how orientation affects the resultant Cr K-edge XANES spectra and the Cr valence ratios that are calculated from them. The data set generated in this work was used to construct a model that mitigates the effects of anisotropy of the calculated Cr2+/?Cr values. The application of this correction procedure as a part of spectral processing improves the overall accuracy of the resultant Cr2+/?Cr values by nearly a factor of five. The increased accuracy of the XANES measured Cr valence ratios afforded by the anisotropy correction reduces the error on calculated fO2 values from approximately ±1.2 to ±0.25
DS201809-2007
2018
Ren, M.Chakrabarty, A., Mitchell, R.H., Ren, M., Sen, A.K., Supriyo, P., Supratim, P.Nb Zr REE re-mobilization and implications for transitional agpaitic rock formation: insights from the Sushin a Hill complex, India.Petrology, doi: 10.1093/petrology/egy084Indianepheline syenite

Abstract: The formation of transitional agpaitic rocks is not a well understood process as there are few studies of miaskitic to agpaitic transitions. The Mesoproterozoic Sushina Hill complex (India) provides a suitable site to investigate these "transitions" as this complex hosts diverse miaskitic and agpaitic nepheline syenites, together with syenites containing exotic mineral assemblages. In this study, we have used mineralogical and geochemical data to describe the evolution of the transitional agpaitic rocks occurring at Sushina Hill. In common with other occurrences, high field strength elements (HFSE) in miaskitic nepheline syenites are mainly sequestered by primary zircon and magnetite. In contrast, the major HFSE carriers in agpaitic nepheline syenites (agpaitic unit-I) are late-magmatic eudialyte and rinkite-(Ce) - nacareniobsite-(Ce), formed at T between 825° - 784ºC and aSiO2 in the range of 0.41 - 0.44. With decreasing temperature (? 575ºC) and aSiO2(0.30), coupled with an increase in aH2O, this assemblage has undergone extensive subsolidus alteration leading to the decomposition of late-magmatic eudialyte to wöhlerite - marianoite, alkali-zirconosilicates (catapleiite/gaidonnyaite, hilairite), and pectolite - serandite. Decomposition of late-magmatic eudialyte resulted in a more alkaline fluid by increasing the a(Na+)/a(Cl-) ratio, facilitating crystallization of hydrothermal eudialyte replacing late-magmatic eudialyte. Crystallization of hydrothermal eudialyte leads to evolving fluids which are less alkaline, resulting in the crystallization of a transitional agpaitic assemblage of pyrochlore + zircon + niobokupletskite + wadeite in agpaitic unit-II in the temperature range 547º - 455ºC with aSiO2 in the range 0.27 - 0.25. Regional scale deformation contemporaneous with the subsolidus alteration stage leads to separation of the evolving fluid from the system, resulting in extensive albitization, with superposition of a new miaskitic-like assemblage in syenite I in the form of late-stage zircon - magnetite - xenotime - monazite-(Ce) upon the early assemblage of primary zircon and magnetite. During deformation, syenite unit-II composed of eudialyte - albite - aegirine was also formed and considered as a later stage pegmatitic offshoot of agpaitic unit I. The mineralogical changes are also complemented by variations in the bulk-rock composition in which the total REE, Nb, U and Th concentrations increase in order from: miaskitic unit ? agpaitic unit I ? syenite unit II, -I ? agpaitic unit II at constant Zr concentration. This suggests that the REE-Nb are mainly mobilized in agpaitic unit-II during the agpaitic - to - transitional agpaitic assemblage transformation in a relatively less alkaline environment.
DS2003-1502
2003
Ren, X.Wu, F., Walker, R.J., Ren, X., Sun, D., Zhou, X.Osmium isotopic constraints on the age of lithospheric mantle beneath northeasternChemical Geology, Vol. 196, No. 1-4, pp. 107-129.ChinaGeochronology
DS200412-2149
2003
Ren, X.Wu, F., Walker, R.J., Ren, X., Sun, D., Zhou, X.Osmium isotopic constraints on the age of lithospheric mantle beneath northeastern China.Chemical Geology, Vol. 196, no. 1-4, pp. 107-129.ChinaGeochronology
DS200612-0071
2006
Ren, Y.Bai, W., Ren, Y., Yang, J., Fang, Q., Yan, B.The native iron and wustite assemblage: records of oxygen element from the mantle.Acta Geologica Sinica , Vol. 27, 1, pp. 43-50.MantleMineral chemistry
DS200712-0890
2007
Ren, Y.Ren, Y., Stutmann, E., Van der Hilst, R.D., besse, J.Understanding seismic heterogeneities in the lower mantle: beneath the Americas from seismic tomography and plate tectonic history.Journal of Geophysical Research, Vol. 112, B1, Jan. 17, B01302.MantleTectonics, geophysics
DS200712-0892
2007
Ren, Y.Ribe, N.M., Stutzmann, E., Ren, Y., Van der Hilst, R.Bucking instabilities of subducted lithosphere beneath the transition zone.Earth and Planetary Science Letters, Vol. 254, 1-2, Feb. 15, pp. 173-179.MantleSubduction
DS201012-0440
2010
Ren, Z-Y.Li, J.,Xu, J-F., Suzuki, K., He, B., Xu, Y-G., Ren, Z-Y.Os, Nd and Sr isotope and trace element geochemistry of the Muli picrites: insights into the mantle source of the Emeishan large igneous province.Lithos, in press available, 15p.ChinaGeochronology
DS201312-0536
2014
Ren, Z-Y.Li, J., Wang,-C., Ren, Z-Y., Xu, J-F., He, B., Xu, Y-G.Chemical heterogeneity of the Emeishan mantle plume: evidence from highly siderophile element abundances in picrites.Journal of Asian Earth Studies, Vol. 79, A, pp. 191-205.ChinaPicrite
DS1993-1294
1993
Ren HuaixiangRen Huaixiang, Zhang GuangwenGeology of the lamproites in Majiang, Guizdou. *CHIGuizhou Dizhi, *CHI, Vol. 10, No. 5, pp. 189-191.ChinaLamproites
DS1993-1295
1993
Ren HuaixingRen Huaixing, Zhang GuangwenGeology of the lamproites in Majiang, Guizhou. *CHIGuizhou-Dizhi, *CHI, Vol. 10, No. 3, pp. 189-191.ChinaLamproite, Deposit -Majiang
DS1995-1563
1995
Ren LuRen Lu, Keppler, H.Speciation and solubility of hydroxyl in pyrope garnetEos, Vol. 76, No. 46, Nov. 7. p.F682. Abstract.AlpsPetrology - garnet
DS1990-1220
1990
Ren YingchenRen Yingchen, Chao, E.C.T.The periods of mineralization and mineral assemblages of the Bayan Oboiron-Nb-rare earth elements (REE) ore deposit of inner MongoliaInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 950-951ChinaMineralization, Baiyan Obo
DS1990-0956
1990
Ren YingxinLu Fengxiang, Ren Yingxin, Zheng Jianping, Taylor, L.A.Green garnets from Liaoning kimberlite, ChinaInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 493-494ChinaMineralogy -garnets, Liaoning
DS200412-1349
2004
RenacMoine, B.N., Gregoire, M., O'Reilly, S.Y., Delpech, G., Sheppard, S.M.F., Lorand, J.P., Renac, Giret, CottinCarbonatite melt in oceanic upper mantle beneath the Kerguelen Archipelago.Lithos, Vol. 75, pp. 239-252.Kerguelen IslandsCarbonatite, harzburgite, metasomatism
DS200712-1157
2007
Renac, C.Williams, H.M., Nielsen, S.G., Renac, C., McCammon, C.A., Griffin, W.L., O'Reilly, S.Y.Fractionation of Fe and O isotopes in the mantle: implications for the origins of eclogites and the source regions of mantle plumes.Plates, Plumes, and Paradigms, 1p. abstract p. A1118.MantleSubduction
DS201112-0386
2011
Renac, C.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
DS1975-0722
1978
Renard, J.G.R.Cundari, A., Renard, J.G.R., Gleadow, A.J.W.Uranium-potassium Relationship and Apatite Fission Track Ages for a Differentiated Leucitite Suite from New South Wales.Chemical Geology, Vol. 22, No. 1, PP. 11-20.Australia, New South WalesLeucite, Geochronology
DS200712-1037
2006
Renaut, R.A.Stefan, W., Garnero, E., Renaut, R.A.Signal restoration through deconvolution applied to deep mantle seismic probes.Geophysical Journal International, Vol. 167, 3, Dec. 1, pp. 1353-1362.MantleGeophysics - seismics
DS1993-1296
1993
Rencz, A.Rencz, A., Harris, J., Toubourg, J., Ballantye, B., Green, S.Remote sensing applications in geosciences: a an introductionProspectors and Developers Association of Canada (PDAC) Meeting Workshop held April 1, Toronto, approx. 100pGlobalBook -table of contents, Remote sensing
DS2001-0450
2001
Rencz, A.Harris, J.R., Eddy, B., Rencz, A., De Kemp, et al.Remote sensing as a geological mapping took in the Arctic: preliminary results from Baffin Island.Can. Geological Survey Current Research, No. 2001-E12, 22p.Northwest Territories, Nunavut, Baffin IslandRemote sensing
DS2001-1050
2001
Rencz, A.Seneshen, D., Grunsky, E., Rencz, A., Hall, G., Dunn, C.Geochemical exploration for kimberlites in northern Alberta37th. Forum Industrial Minerals;, May 23-5, pp. 33-4.AlbertaGeochemistry
DS1985-0196
1985
Rencz, A.N.Ford, K.L., Dilabio, R.N.W., Rencz, A.N.Preliminary Results of Multidisciplinary Studies Around The recently Discovered Allan Lake Carbonatite, Algonquin Park, ontario.11th. International Geochem. Symposium Held Toronto, April 28-may, ABSTRACT VOLUME P. 70. (abstract.).Canada, OntarioCarbonatite
DS1988-0220
1988
Rencz, A.N.Ford, K.L., Dilabio, R.N.W., Rencz, A.N.Geological, geophysical and geochemical studies around the Allan Lakecarbonatite, Algonquin Park,OntarioJournal of Geochemical Exploration, Vol. 30, No. 2, July pp. 99-122OntarioCarbonatite, Allan Lake
DS1992-1269
1992
Rencz, A.N.Rencz, A.N., Aylsworth, J.M., Shilts, W.W.Application of Land sat Thematic Mapper dat a to mapping surficial geologyGeological Survey Canada Open File: project summaries Canada-northwest Territories agreement, OF 2484, March pp. 153-154.Northwest TerritoriesRemote sensing, Geomorphology
DS1995-0033
1995
Rencz, A.N.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
DS1996-0163
1996
Rencz, A.N.Bowie, C., Kjarsgaard, B.A., Broome, H.J., Rencz, A.N.GIS activities related to diamond research and exploration Lac de Grasarea, northwest Territories.Geological Survey of Canada, LeCheminant ed, OF 3228, pp. 259-263.Northwest TerritoriesGIS - digital database, Overview
DS1996-1176
1996
Rencz, A.N.Rencz, A.N., Bowie, C., Ward, B.C.Application of thermal imagery from Land sat dat a to locate kimberlites, Lacde Gras area, northwest Territories.Geological Survey of Canada, LeCheminant ed, OF 3228, pp. 255-257.Northwest TerritoriesLandsat Thematic Mapper data, Lac de Gras area
DS200612-0208
2006
Rendeng, S.Cailai, W., Wooden, J.L., Jingsui, Y., Robinson, P.T., Lingsen, Z., Rendeng, S., Songyong, C.Granitic magmatism in the North Qaidam Early Paleozoic Ultra high pressure metamorphic belt, northwest China.International Geology Review, Vol. 48, 3, pp. 223-240.Asia, ChinaUHP
DS2000-0357
2000
Render, F.Grasby, S., Osadetz, K., Betcher, R., Render, F.Reversal of the regional scale flow system of the Williston Basin in response to Pleistocene glaciationGeology, Vol. 28, No. 7, July, pp. 635-8.Alberta, Saskatchewan, Manitoba, MontanaGeomorphology, glaciation
DS1994-1448
1994
Rendu, J.M.Rendu, J.M.Mining geostatistics -fourty years passed. What lies ahead?Mining Engineering, Vol. 46, No. 6, June pp. 557-558GlobalGeostatistics, Brief review
DS2001-0972
2001
Rendu, J.M.Rendu, J.M., Miskelly, N.Mineral resources and mineral reserves: progress on international definitions and reporting standards.Institute of Mining and Metallurgy Transactions, Vol.110, pt.A.pp. A133-8.GlobalEconomics, reserves, resources, exploration
DS2002-1060
2002
Rendu, J.M.Miskelly, N., Rendu, J.M.Mineral resources and mineral reserves - progress on international definitions and reporting standards.Australian Institute of Mining and Metallurgy, No. 3/2002, pp.47-52.GlobalMineral reserves - definitions, category, Competent person
DS1995-1564
1995
Rene, R.M.Rene, R.M., Stanonis, F.L.Reflection seismic profiling of the Wabash Valley fault system in the Illinois Basin.United States Geological Survey (USGS) Prof. paper, No. 1538- O, 33p.Midcontinent, IllinoisGeophysics - seismics
DS1996-1177
1996
Renehan, E.J.Renehan, E.J.Science on the web... connoisseur's guide to over 500 of the best, most useful and most fun science websitesSpringer Publ, 400p. approx. $ 20.00 United StatesGlobalBook - table of contents, Websites
DS1992-0084
1992
Renez, A.Baril, D., Renez, A., Thompson, P.H., Broome, H.J., Barrie, C.T.NATMAP Slave project: integrating LANDSAT, ERSI Radar, aeromagnetic and geological dat a for regional mappingNorthwest Territories Geoscience Forum held November 25, 26th. 1992, poster, AbstractNorthwest TerritoriesMapping, GIS
DS201509-0424
2015
RenfroRenfroDigital photomicrography for gemologists.Gems & Gemology, Summer pp. 144-159.TechnologyPhotomicrography

Abstract: Until recently, film was the preferred medium used for capturing images through the microscope, primarily due to resolution limitations of digital-format cameras. The image quality that can now be achieved by digital cameras is equal, and in many ways superior, to the quality offered by film. Digital photomicrography allows gemologists the opportunity to instantly see the resultant images, which can then be adjusted with image-refining software so that they represent their subject as realistically as possible. This article offers examples of some basic techniques and tips on the application of digital processing to get the most out of photomicrographs.
DS200512-0238
2004
Renfro, A.P.Dobrzhinetskaya, L.F., Green, H.W., Renfro, A.P., Bozhilov, K.N., Spengler, D., Van Roemund, H.L.M.Precipitation of pyroxenes and Mg2SiO4 from majorite garnet: simulation of peridotite exhumation from great depth.Terra Nova, Vol. 16, 6, pp. 325-330.MantlePetrology - peridotite
DS200512-0239
2004
Renfro, A.P.Dobrzhinetskaya, L.F., Renfro, A.P., Green, H.W.II.Synthesis of skeletal diamonds: implications for microdiamond formation in orogenic belts.Geology, Vol. 32, 10, Oct. pp. 869-872.KazakhstanUHP, C-O-H fluid, Kokchetav massif
DS201212-0664
2012
Renfro, N.Skalwold, E.A., Renfro, N.,Shigley, J.E., Breeding, C.M.Characterization of a synthetic nano-polycrustalline diamond gemstone.Gems & Gemology, Vol. 48, 3, pp. 188-192.TechnologySynthetics
DS201511-1870
2015
Renfro, N.Renfro, N.The application of differential interference contrast microscopy to gemmology.Journal of Gemmology, Vol. 34, 7, pp. 616-622.TechnologyLuminescence
DS201604-0633
2015
Renfro, N.Sun, Z., Palke, A.C., Renfro, N.Vanadium and chromium bearing pink pyrope garnet: characterization and quantitative colorimetric analysis. Gems & Gemology, Vol. 51, 4, winter pp. 348-369.Africa, TanzaniaGarnet, pyrope

Abstract: A type of pink pyrope garnet containing vanadium and chromium, believed to have been mined in Tanzania, appeared at the 2015 Tucson shows. The material shows a noticeable color difference from purplish pink under incandescent light (A) to purple under daylight-equivalent light (D65). This study reports a quantitative analysis of the difference in color between the two lighting conditions, based on the use of high-quality visible absorption spectroscopy to calculate CIELAB 1976 colorimetric coordinates. L*, a*, and b* colorimetric parameters were calculated for a wide range of path lengths as extrapolated from visible absorption spectra of thinner samples. Using this method, the path length of light through the stone that produces the optimal color difference can be calculated. This path length can then be used to determine the optimal depth range to maximize color change for a round brilliant of a specific material. The pink pyrope studied here can be designated as "color-change" garnet according to certain classification schemes proposed by other researchers. In many of these schemes, however, the material fails to exceed the minimum requirements for quantitative color difference and hue angle difference to be described as "color-change." Nonetheless, there is no simple solution to the problem of applying color coordinates to classify color-change phenomena. Also presented is a method by which spectra can be corrected for reflection loss and accurately extrapolated to stones with various path lengths.
DS202104-0603
2021
Renfro, N.Renfro, N., Palke, A.Microfeatures of gems: geologic implications ( diamond and other gemstones)gia.org and knowledge session utube, 44266Globaldiamond inclusions

Abstract: Inclusions are more than imperfections or clarity characteristics. They can teach us much about gemstones’ journeys and reveal otherwise inaccessible information about Earth’s formation. What stories do diamond inclusions tell about Earth’s mantle? What do rutile needles and three-phase inclusions teach us about corundum and emerald, respectively? Follow Manager of Gem Identification Nathan Renfro and Senior Manager of Research Dr. Aaron Palke as they offer an up-close look into the microworld of gems and show us how this world reveals secrets about Earth’s geologic processes at large.
DS202108-1281
2021
Renfro, N.Eaton-Magana, S., Renfro, N., Vavadiya, A.Diamond shaped cloud in diamond.Gems & Gemology , Vol. 57, 1, pp. 65-66.Globaldiamond morphology
DS201608-1429
2016
Renfro, N.D.Palke, A.C., Renfro, N.D., Berg, R.B.Origin of sapphires from lamprophyre dike at Yogo Gulch, Montana USA: clues to their melt inclusions.Lithos, Vol. 260, pp. 339-344.United States, MontanaSapphires

Abstract: Gem corundum (sapphire) has been mined from an ultramafic lamprophyre dike at Yogo Gulch in central Montana for over 100 years. The sapphires bear signs of corrosion showing that they were not in equilibrium with the lamprophyre that transported them; however, their genesis is poorly understood. We report here the observation of minute glassy melt inclusions in Yogo sapphires. These inclusions are Na- and Ca-rich, Fe-, Mg-, and K-poor silicate glasses with compositions unlike that of the host lamprophyre. Larger, recrystallized melt inclusions contain analcime and calcite drawing a striking resemblance to leucocratic ocelli in the lamprophyre. We suggest here that sapphires formed through partial melting of Al-rich rocks, likely as the lamprophyre pooled at the base of the continental crust. This idea is corroborated by MELTS calculations on a kyanite-eclogite protolith which was presumably derived from a troctolite precursor. These calculations suggest that corundum can form through peritectic melting of kyanite. Linking the melt inclusions petrologically to the lamprophyre represents a significant advancement in our understanding of sapphire genesis and sheds light on how mantle-derived magmas may interact with the continental crust on their ascent to the surface.
DS201705-0869
2017
Renfro, N.D.Palke, A.C., Renfro, N.D., Berg, R.B.Melt inclusions in alluvial sapphires from Montana, USA: formation of sapphires as a restitic component of lower crustal melting?Lithos, Vol. 278-281, pp. 43-53.United States, MontanaSapphires

Abstract: We report here compositions of glassy melt inclusions hosted in sapphires (gem quality corundum) from three alluvial deposits in Montana, USA including the Rock Creek, Dry Cottonwood Creek, and Missouri River deposits. While it is likely that sapphires in these deposits were transported to the surface by Eocene age volcanic events, their ultimate origin is still controversial with many models suggesting the sapphires are xenocrysts with a metamorphic or metasomatic genesis. Melt inclusions are trachytic, dacitic, and rhyolitic in composition. Microscopic observations allow separation between primary and secondary melt inclusions. The primary melt inclusions represent the silicate liquid that was present at the time of sapphire formation and are enriched in volatile components (8-14 wt.%). Secondary melt inclusions analyzed here for Dry Cottonwood Creek and Rock Creek sapphires are relatively volatile depleted and represent the magma that carried the sapphires to the surface. We propose that alluvial Montana sapphires from these deposits formed through a peritectic melting reaction during partial melting of a hydrated plagioclase-rich protolith (e.g. an anorthosite). The heat needed to drive this reaction was likely derived from the intrusion of mantle-derived mafic magmas near the base of the continental lithosphere during rollback of the Farallon slab around 50 Ma. These mafic magmas may have ended up as the ultimate carrier of the sapphires to the surface as evidenced by the French Bar trachybasalt near the Missouri River deposit. Alternatively, the trachytic, rhyolitic, and dacitic secondary melt inclusions at Rock Creek and Dry Cottonwood Creek suggests that the same magmas produced during the partial melting event that generated the sapphires may have also transported them to the surface. Determining the genesis of these deposits will further our understanding of sapphire deposits around the world and may help guide future sapphire prospecting techniques. This work is also important to help reveal the history of mantle-derived mafic magmas as they pass through the continental crust.
DS201809-2080
2018
Renfro, N.D.Renfro, N.D., Palke, A.C., Berg, R.B.Gemological characterization of sapphires from Yogo Gulch, Montana.Gems & Gemology, Vol. 54, 2, pp. 184-201.United States, Montanadeposit - Yogo Gulch

Abstract: Yogo Gulch in central Montana is one of the most important gem deposits in the United States. Although very little material has been recovered there in recent years, it has produced several million carats of rough sapphire over the course of its history (Voynick, 2001). These stones, known for their vibrant untreated blue color and high clarity, have always commanded a price premium, especially in sizes larger than 0.75 ct. This paper offers a thorough gemological characterization of Yogo sapphire, which may be unfamiliar to many gemologists. Fortunately, Yogo sapphires are unique and experienced gemologists can easily separate them from gem corundum of different geographic origins throughout the world, making it possible to determine the provenance of important stones from this deposit.
DS201903-0540
2018
Renfro, N.D.Renfro, N.D., Koivula, J.I., Muyal, J., McClure, S.F., Schumacher, K., Shigley, J.E.Inclusions in natural, synthetic, and treated diamonds. Gems & Gemology, Vol. 54, 4, pp. 428-429.Globaldiamond inclusions
DS202003-0341
2019
Renfro, N.D.Groat, L.A., Giuilani, G.,, Stone-Sundberg, J., Sun, Z., Renfro, N.D., Palke, A.C.A review of analytical methods used in geographic origin determination of gemstones.Gems & Gemology, Vol. 55, 4, pp. 512-535.Globalemerald, sapphire

Abstract: Origin determination is of increasing importance in the gem trade. It is possible because there is a close relationship between the geological environment of formation and the physical and chemical properties of gemstones, such as trace element and isotopic compositions, that can be measured in the laboratory using combinations of increasingly sophisticated instrumentation. Origin conclusions for ruby, sapphire, and emerald make up the bulk of demand for these services, with growing demand for alexandrite, tourmaline, and spinel. However, establishing origin with a high degree of confidence using the capabilities available today is met with varying degrees of success. Geographic origin can be determined with a high level of confidence for materials such as emerald, Paraíba-type tourmaline, alexandrite, and many rubies. For some materials, especially blue sapphire and some rubies, the situation is more difficult. The main problem is that if the geology of two deposits is similar, then the properties of the gemstones they produce will also be similar, to the point where concluding an origin becomes seemingly impossible in some cases. Origin determination currently relies on a combination of traditional gemological observations and advanced analytical instrumentation.
DS202003-0355
2019
Renfro, N.D.Palke, A.C., Saeseaw, S., Renfro, N.D., Sun, Z., McClure, S.F.Geographic origin of ruby.Gems & Gemology, Vol. 55, 4, pp. 580-579.Global, Asia, Myanmar, Vietnam, Cambodia, Thailand, Africa, Madagascar, Mozambique, Europe, Afghanistanruby

Abstract: Over the last several decades, geographic origin determination for fine rubies has become increasingly important in the gem trade. In the gemological laboratory, rubies are generally broken down into two groups based on their trace element chemistry: marble-hosted (low-iron) rubies and high-iron rubies. High-iron rubies are usually a straightforward identification based on their inclusions and trace element profiles. Marble-hosted rubies can be more challenging, with some deposits showing overlap in some of their inclusion scenes. But many marblehosted rubies, especially Burmese stones from Mogok and Mong Hsu, can be accurately identified based on their internal features and trace element profiles. This contribution will outline the methods and criteria used at GIA for geographic origin determination for ruby.
DS202003-0359
2019
Renfro, N.D.Saeseaw, S., Renfro, N.D., Palke, A.C., Sun, Z., McClure, S.F.Geographic origin of emerald.Gems & Gemology, Vol. 55, 4, pp. 614-647.South America, Colombia, China, Europe, Afghanistan, Africa, Zambiaemerald

Abstract: The gem trade has grown to rely on gemological laboratories to provide origin determination services for emeralds and other fine colored stones. In the laboratory, this is mostly accomplished by careful observations of inclusion characteristics, spectroscopic analysis, and trace element profile measurements by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Inclusions and spectroscopy can often separate Colombian emeralds from other sources (although there is some overlap between Colombian, Afghan, and Chinese [Davdar] emeralds). For non-Colombian emeralds, trace element analysis by LA-ICP-MS is needed in addition to information from the stone’s inclusions. The relative chemical diversity of emeralds from worldwide deposits allows confidence in origin determination in most cases. This contribution outlines the methods and criteria used at GIA for geographic origin determination for emerald.
DS202003-0369
2019
Renfro, N.D.Vertriest, W., Palke, A.C., Renfro, N.D.Field gemology: building a research collection and understanding the development of gem deposits.Gems & Gemology, Vol. 55, 4, pp. 490-511.United StatesGIA

Abstract: GIA’s field gemology program was established in late 2008 to support research on geographic origin determination of colored gemstones. By building and maintaining an extensive collection of gem materials with known origins, GIA’s research scientists have been able to study and analyze rubies, sapphires, emeralds, and other gemstones using the best available reference samples. This has led to improved origin determination services while supporting numerous research and education projects. To date the collection has accumulated during more than 95 field expeditions on six continents and currently includes more than 22,000 samples. GIA’s field gemology efforts require a thorough understanding of the gem trade, including the evolution of gemstone deposits and the development of treatments. It is important to recognize potential new deposits and gemstone enhancement procedures immediately because they can change rapidly and leave a lasting impact on the trade. Field expeditions also involve documenting the mines and local conditions. These factors provide context for the gemstones and are becoming increasingly important in the eyes of the public.
DS201801-0002
2017
Rengarajan, M.Balasubramani, S., Sahoo, P., Bhattacharya, D., Rengarajan, M., Thangavel, S., Bhatt, A.K., Verma, M.B., Nanda, L.K.A note on anomalous concentration of scandium in the Pakkanadu alkaline complex, Salem District, Tamil Nadu, India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 46.Indiaalkaline rocks

Abstract: Pakkanadu Alkaline complex (PAC) of Neoproterozoic age is located at the southwestern end of Dharmapuri rift/shear zone on the northern part of southern granulitic terrain in Tamil Nadu, India. PAC mainly comprises carbonatite-syenitepyroxenite suite of rocks. Syenite is the predominant rock exposed on the eastern and western part of the explored area with enclaves of pyroxenite and dunite. The carbonatite (sovite) occurs as thin veins/bands and discontinuous lenticular bodies intrusive into highly deformed biotite schist that is considered as the fenitised product of pyroxenite traceable over a strike length of 1.5 km. Petromineralogical study of the biotite schist, pyroxenite containing carbonatite rock and carbonatite indicated presence of monazite, allanite, sphene and betafite as the main radioactive minerals occurring as inclusion within biotite or as discrete mineral grains. Other ore minerals are apatite, thorite, titanite, rutile and barite. Chloritisation, hematitisation, silicification and calcitisation are the main wall rock alteration observed in pyroxenite and syenite. Sub-surface exploration carried out by Atomic Minerals Directorate (AMD) in PAC revealed that biotite schist (n=166) contains anomalously high concentration of Scandium (11-1275 ppm, av.161 ppm), REE (67-58275 ppm, av. 14836 ppm,) and V (5-620 ppm, av. 127 ppm, with carbonatite veins and syenite (n=149) contain scandium (10-462 ppm, av.71 ppm,), REE (18-57510 ppm, av. 4106 ppm) and V (1-285 ppm, av. 48 ppm). In these rocks, LREE (12.5-57670 ppm, av. 9617 ppm, n=315) shows enrichment over HREE (7.1-774 ppm, av. 173 ppm, n=315). The concentration of Scandium (Av. 166 and 71 ppm in biotite schist and syenite respectively) is anomalous as compared to its crustal abundance (22 ppm). Geochemical analyses of the rock indicate that the radioactive biotite schist, pyroxenite containing carbonatite veins generally shows higher Sc and REE concentrations as compared to those of the other rocks (syenite). However, there is no significant correlation between REE and Sc. The higher concentration of scandium in PAC is possibly due to selective partitioning of it into minerals like apatite, pyrochlore, allanite, monazite and other REE bearing phases, apart from its concentration in the ferromagnesian minerals. Scandium rarely concentrates in nature as independent ore mineral. The demand for the metal is very high due to multiple high value commercial uses as an alloy with aluminum, specifically in aerospace and automobile industry, besides, in solid oxide fuel cells (SOFC) in electrical industries. Eight boreholes drilled as part of the preliminary subsurface exploration in PAC, covering an area of 0.05 sq. km, indicated an elevated Scandium content of about 6 times that of the average crustal abundance.
DS201808-1786
2018
Renjith, M.L.Satyanarayanan, M., Subba Rao, D.V., Renjith, M.L., Singh, S.P., Babu, E.V.S.S.K., Korakoppa, M.M.Petrogenesis of carbonatitic lamproitic dykes from Sidhi gneissic complex, central India.Geoscience Frontiers, Vol. 9, 2, pp. 531-547.Indialamproite

Abstract: Petrographic, mineral chemical and whole-rock geochemical characteristics of two newly discovered lamproitic dykes (Dyke 1 and Dyke 2) from the Sidhi Gneissic Complex (SGC), Central India are presented here. Both these dykes have almost similar sequence of mineral-textural patterns indicative of: (1) an early cumulate forming event in a deeper magma chamber where megacrystic/large size phenocrysts of phlogopites have crystallized along with subordinate amount of olivine and clinopyroxene; (2) crystallization at shallow crustal levels promoted fine-grained phlogopite, K-feldspar, calcite and Fe-Ti oxides in the groundmass; (3) dyke emplacement related quench texture (plumose K-feldspar, acicular phlogopites) and finally (4) post emplacement autometasomatism by hydrothermal fluids which percolated as micro-veins and altered the mafic phases. Phlogopite phenocrysts often display resorption textures together with growth zoning indicating that during their crystallization equilibrium at the crystal-melt interface fluctuated multiple times probably due to incremental addition or chaotic dynamic self mixing of the lamproitic magma. Carbonate aggregates as late stage melt segregation are common in both these dykes, however their micro-xenolithic forms suggest that assimilation with a plutonic carbonatite body also played a key role in enhancing the carbonatitic nature of these dykes. Geochemically both dykes are ultrapotassic (K2O/Na2O: 3.0 -9.4) with low CaO, Al2O3 and Na2O content and high SiO2 (53.3 -55.6 wt.%) and K2O/Al2O3 ratio (0.51 -0.89) characterizing them as high-silica lamproites. Inspite of these similarities, many other features indicate that both these dykes have evolved independently from two distinct magmas. In dyke 1, phlogopite composition has evolved towards the minette trend (Al-enrichment) from a differentiated parental magma having low MgO, Ni and Cr content; whereas in dyke 2, phlogopite composition shows an evolutionary affinity towards the lamproite trend (Al-depletion) and crystallized from a more primitive magma having high MgO, Ni and Cr content. Whole-rock trace-elements signatures like enriched LREE, LILE, negative Nb-Ta and positive Pb anomalies; high Rb/Sr, Th/La, Ba/Nb, and low Ba/Rb, Sm/La, Nb/U ratios in both dykes indicate that their parental magmas were sourced from a subduction modified garnet facies mantle containing phlogopite. From various evidences it is proposed that the petrogenesis of studied lamproitic dykes stand out to be an example for the lamproite magma which attained a carbonatitic character and undergone diverse chemical evolution in response to parental melt composition, storage at deep crustal level and autometasomatism.
DS2002-0469
2002
Renka, R.J.Fohlmeister, J.F., Renka, R.J.Distribution of mantle up welling determined from plate motions: a case for large scale Benard Convection.Geophysical Research Letters, Vol. 29, 10, DOI 10.1029/2001GL014625MantleHot spots, plumes
DS1999-0591
1999
Renkamper, M.Renkamper, M., Halliday, A.N., Takazawa, E.Non-chondritic platinum group element ratios in oceanic mantle lithosphere:petrogenetic signature melt...Earth and Planetary Science Letters, Vol. 172, No. 1-2, Oct. 15, pp. 65-82.MantlePlatinum group elements, Melt percolation
DS200512-0716
2005
RennaMelluso, L., Morra, V., Bortsu, P., Tommasini, S., Renna, MR, Duncan, R., Franciosi, L., D'Amelio, F.Geochronology and petrogenesis of the Cretaceous Antampombato Ambatovy Complex and associated dyke swarm, Madagascar.Journal of Petrology, Vol. 46, 10, pp. 1963-1996.Africa, MadagascarGeochronology - dike
DS2003-0539
2003
Renne, P.Hames, W., McHone, J.G., Renne, P., Ruppel, C.The central Atlantic magmatic province: insights from fragments of PangeaAmerican Geophysical Union, Geophysical Monograph, No. 136, 330p.Brazil, Morocco, Guinea, Guyana, MauritaniaMagmatism
DS200412-0770
2003
Renne, P.Hames, W., McHone, J.G., Renne, P., Ruppel, C.The central Atlantic magmatic province: insights from fragments of Pangea.American Geophysical Union, Geophysical Monograph, No. 136, 330p.South America, Brazil, Guyana, Africa, Guinea, MauritaniaMagmatism
DS1990-0384
1990
Renne, P.R.D'Agrella-Filho, M.S., Pacca, I.G., Renne, P.R., Onstott, T.C.Paleomagnetism and middle Proterozoic (1.01 to 1.08 Ga) mafic dykes in southeastern Bahia State-Sao Francisco Craton, BrasilEarth and Planetary Science Letters, Vol. 101, No. 2/4, December pp. 332-348BrazilPaleomagnetism, Dykes
DS1990-1221
1990
Renne, P.R.Renne, P.R., Onstott, T.C., D'Agrella-Filho, M.S., Pacca, I.G.40 Ar-39 Ar dating of 1.0-1.1 Ga magnetizations from the Sao Francisco and Kalahari cratons: tectonic implicationsPan-African and Brasiliano mobilebeltsEarth and Planetary Science Letters, Vol. 101, No. 2/4, December pp. 349-367Brazil, southern AfricaPaleomagnetism, Argon, Craton
DS1998-0952
1998
Renne, P.R.Marzoli, A., Renne, P.R., et al.The earliest Jurassic circum Atlantic large igneous province: new evidence for a brief extremely widespreadMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 961-2.BrazilMagmatism, Geochronology
DS1999-0731
1999
Renne, P.R.Teixeira, W., Renne, P.R., D'Agrella Filho, M.S.40 Ar-39 Ar and Rubidium-Strontium geochronology of the Urugurayan dike swarm, Rio de la Plat a Craton.... Proterozoic...Precambrian Research, Vol. 92, No. 2-3, Jan. 31, pp. 153-180.UruguayGeochronology, dike swarm, Argon, Rubidium, Tectonics - Gondwana
DS2000-0381
2000
Renne, P.R.Hames, W.E., Renne, P.R.New evidence for geologically instantaneous emplacement of earliest Jurassic Central Atlantic magmatic provinceGeology, Vol. 28, No. 9, Sept. pp. 859-62.United StatesDike swarm
DS200412-1443
2004
Renne, P.R.Nomade, S., Renne, P.R., Merkle, K.W.40 Ar 39 Ar age constraints on ore deposition and cooling of the Bushveld Complex, South Africa.Journal of Geological Society of London, Vol. 161, 3, pp. 411-420.Africa, South AfricaGeochronology - Kaapval Craton
DS200512-0083
2005
Renne, P.R.Beutel, E.K., Nomade, S., Fronabarger, A.K., Renne, P.R.Pangea's complex breakup: a new rapidly changing stress field model.Earth and Planetary Science Letters, Vol. 236, pp. 471-485.Pangea, United States, CarolinasDike, geochronology, plume, geochemistry
DS200712-0912
2007
Renne, P.R.Rosset, A., De Min, A., Marques, L.S., Macambira, M.J.B., Ernesto, M., Renne, P.R., Piccrillo, E.M.Genesis and geodynamic significance of Mesoproterozoic and Early Cretaceous tholeiitic dyke swarms from the Sao Francisco Craton, Brazil.Journal of South American Earth Sciences, Vol. 24, 1, June pp. 69-92.South America, BrazilDyke swarms
DS201703-0396
2017
Renne, P.R.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.
DS201112-0289
2011
Renner, J.Druiventak, A., Trepmann, C.A., Renner, J., Hanke, K.Low temperature plasticity of olivine during high stress deformation of peridotite at lithospheric conditions - an experimental study.Earth and Planetary Science Letters, Vol. 311, 3-4, pp. 199-211.MantlePeridotite
DS201201-0841
2011
Renner, J.Druiventak, A., Matsiak, A., Renner, J., Trepmann, C.A.Kick and cook experiments on peridotite: simulating coseismic deformation and post-seismic creep.Terra Nova, In press available,MantleGeophysics - seismics
DS201212-0171
2012
Renner, J.Druiventak, A., Matsyiak, A., Renner, J., Trepmann, C.Kick and cook experiments on peridotite: simulating coseismic deformation post-seismic creep.Terra Nova, Vol. 24, 1, pp. 62-69.MantleGeophysics - seismics
DS1993-1297
1993
Renner, R.Renner, R.The hottest rocks on earth... ancient lavas.. earth's crust.. komatiites.History of researchNew Scientist, July 24, pp. 23-27South Africa, ZimbabweGreenstone belts, History of komatiites
DS1975-1199
1979
Rennie, J.C.Rennie, J.C.Ashton Joint Venture Report Issued July 10th. Attachment To letter from Jem to Ajaj August 2nd.Ashton Joint Venture Press Release., 1P.Australia, Western AustraliaSampling, Valuation, Carats, Ratio, Industrial, Gem, Diamond
DS201809-2033
2018
Rennie, L.J.Hansen, R.F., Rennie, L.J.The first Australian diamond.The Australian Gemmologist, Vol. 26, 9-10, pp. 205-208.Australia, New South Wales diamond - Ophir

Abstract: This article describes the first Australian diamond to reach the shores of Britain. Originally donated to the Museum of Practical Geology, it now resides in the Natural History Museum, London. The diamond came from the gold-mining district of Ophir, near Bathurst in New South Wales, and is possibly the earliest found and recognised as a diamond in Australia.
DS2003-0733
2003
Reno, B.Koch-Muller, M., Dera, M., Fei, Y., Reno, B., Sobolev, N., Hauri, E.OH in synthetic and natural coesiteAmerican Mineralogist, Vol. 88, 10, Oct. pp. 1436-45.GlobalMineralogy - coesite
DS200412-1024
2003
Reno, B.Koch-Muller, M., Dera, M., Fei, Y., Reno, B., Sobolev, N., Hauri, E., Wysoczanski, R.OH in synthetic and natural coesite.American Mineralogist, Vol. 88, 10, Oct. pp. 1436-45.TechnologyMineralogy - coesite
DS1992-1270
1992
Renwick, C.J.S.Renwick, C.J.S.Sustainable development-myths, fashions and political opportunisMMinerals Industry International, No. 1006, May pp. 28-32GlobalEconomics, Sustainable development
DS1990-1473
1990
Renze, A.N.Tooker, M., Schewchenko, N., Bonham-Carter, G.F., Renze, A.N.Plotter- a fortran program using UNIRAS for plotting SPANS and EASI/PACEimagesGeological Survey of Canada Open File, No. 2255, 43p. Report and 1 diskette $ 23.00GlobalComputer, Program -PLOTTER.
DS201609-1712
2016
Renzulli, A.Comin-Chiaramonti, P., Renzulli, A., Ridolfi, F., Enrich, G.E.R., Gomes, C.B., De Min, A., Azzone, R.G., Ruberti, E.Late stage magmatic to deuteric metasomatic accessory minerals from the Cerro Boggiani agpaitic complex ( Alto Paraguay alkaline province.Journal of South American Earth Sciences, Vol. 71, pp. 248-261.South America, ParaguayCarbonatite

Abstract: This work describes rare accessory minerals in volcanic and subvolcanic silica-undersaturated peralkaline and agpaitic rocks from the Permo-Triassic Cerro Boggiani complex (Eastern Paraguay) in the Alto Paraguay Alkaline Province. These accessory phases consist of various minerals including Th-U oxides/silicates, Nb-oxide, REE-Sr-Ba bearing carbonates-fluorcarbonates-phosphates-silicates and Zr-Na rich silicates. They form a late-stage magmatic to deuteric/metasomatic assemblage in agpaitic nepheline syenites and phonolite dykes/lava flows made of sodalite, analcime, albite, fluorite, calcite, ilmenite-pyrophanite, titanite and zircon. It is inferred that carbonatitic fluids rich in F, Na and REE percolated into the subvolcanic system and metasomatically interacted with the Cerro Boggiani peralkaline and agpaitic silicate melts at the thermal boundary layers of the magma chamber, during and shortly after their late-stage magmatic crystallization and hydrothermal deuteric alteration.
DS201312-0741
2013
Reolid, M.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
DS2003-1156
2003
Replumaz, A.Replumaz, A., Tapponier, P.Reconstruction of the deformed collision zone between India and Asia by backwardJournal of Geophysical Research, Vol. 108, B6, 10.1029/2002JB000661 June 3India, AsiaTectonics
DS200412-1654
2004
Replumaz, A.Replumaz, A., Karason, H., Van der Hilst, R.D., Besse, J., Tapponnier, P.4 D evolution of SE Asia's mantle from geological reconstructions and seismic tomography.Earth and Planetary Science Letters, Vol. 221, 1-4, pp. 103-115.India, Asia, ChinaGeophysics - seismics, tectonics
DS200412-1655
2003
Replumaz, A.Replumaz, A., Tapponier, P.Reconstruction of the deformed collision zone between India and Asia by backward motion of lithospheric blocks.Journal of Geophysical Research, Vol. 108, B6, 10.1029/2002 JB000661 June 3India, AsiaTectonics
DS201012-0622
2010
Replumaz, A.Replumaz, A., Negredo, A.M., Villasenor, A., Guillot, S.Indian continental subduction and slab break off during Tertiary collision.Terra Nova, Vol. 22, pp. 290-296.IndiaSubduction
DS201810-2367
2018
Replumaz, A.Pitard, P., Replumaz, A., Funiciello, F., Husson, L., Faccenna, C.Mantle kinematics driving collisional subduction: insights from analogue modeling.Earth and Planetary Science Letters, Vol. 502, pp. 96-103.Mantlesubduction

Abstract: Since several decades, the processes allowing for the subduction of the continental lithosphere less dense than the mantle in a collision context have been widely explored, but models that are based upon the premise that slab pull is the prominent driver of plate tectonics fail. The India-Asia collision, where several episodes of continental subduction have been documented, constitute a case study for alternative views. One of these episodes occurred in the early collision time within the Asian plate where continental lithosphere not attached to any oceanic lithosphere subducted southward in front of the Indian lithosphere during its northward subduction that followed the oceanic subduction of the Tethys ocean. This process, known as collisional subduction, has a counter-intuitive behavior since the subduction is not driven by slab pull. It has been speculated that the mantle circulation can play an important role in triggering collisional subduction but a detailed, qualitative analysis of it is not available, yet. In this work we explore the southward subduction dynamics of the Asian lithosphere below Tibet by means of analogue experiments with the aim to highlight how the mantle circulation induces or responds to collisional subduction. We found that during the northward oceanic subduction (analogue of Tethys subduction) attached to the indenter (Indian analogue), the main component of slab motion is driven vertically by its negative buoyancy, while the trench rolls back. In the mantle the convective pattern consists in a pair of wide convective cells on both sides of the slab. But when the indenter starts to bend and plunge in the mantle, trench motion reverses. Its advance transmits the far field forces to two upper plates (Asian analogues). The more viscous frontal plate thickens, and the less viscous hinterland plate, which is attached to the back wall of the box, subducts. During this transition, a pair of sub-lithospheric convective cells is observed on both sides of the Asian analogue slab, driven by the shortening of the frontal plate. It favors the initiation of the backwall plate subduction. Such subduction is maintained during the entire collision by a wide cell with a mostly horizontal mantle flow below Tibet, passively advecting the Asian analogue slab. Experimental results suggest that once the tectonic far-field force related to the forward horizontal motion becomes dominant upon the buoyancy forces, trench advancing and the transmission of the tectonic force to the upper and backwall plates are promoted. This peculiar condition triggers the subduction of the backwall plate, despite it is light and buoyant.
DS2001-0845
2001
reply WhitehouseNutman, A.P., McGregor, V.R., reply Whitehouse, KamberAge significance of uranium-thorium-lead zircon dat a from early Archean rocks of West Greenland - a reassessment basedChemical Geology, Vol. 175, No. 3-4, June 1, pp. 191-99, 201-8.GreenlandGeochronology - ion microprobe, imaging studies
DS2003-1351
2003
Repnikova, E.A.Svetov, S.A., Fofanov, A.D., Smolkin, V.F., Moshkina, E.V., Repnikova, E.A.Real structure and physical properties of chromites as an indicator of their genesisDoklady Earth Sciences, Kola PeninsulaBlank
DS200412-1954
2003
Repnikova, E.A.Svetov, S.A., Fofanov, A.D., Smolkin, V.F., Moshkina, E.V., Repnikova, E.A., Kevlich, V.I.Real structure and physical properties of chromites as an indicator of their genesis.Doklady Earth Sciences, Vol. 393A, 9, pp. 1272-1275.Russia, Kola PeninsulaSpinel mineralogy
DS2001-0425
2001
Repusseau, Ph.Guillen, A., Meunier, Ch., Repusseau, Ph.New internet tools to manage geological and geophysical dataComputers and Geosciences, Vol. 27, No. 5, pp. 563-76.GlobalComputer - World wide web
DS1992-1271
1992
Requeiro, M.N.Requeiro, M.N.Diamond from fullerenesAdvanced Materials, Vol. 4, No. 6, June pp. 438-440. # JB802GlobalFullerenes, Diamond synthesis
DS201507-0323
2016
Requejo, H.S.Mantovani, M.S.M., Louro, V.H.A., Ribeiro, V.B., Requejo, H.S., dos Santos, R.P.Z.Geophysical analysis of Catalao 1 alkaline carbonatite complex in Goias, Brazil.Geophysical Prospecting, Vol. 64, pp. 216-227.South America, BrazilDeposit - Catalao
DS201602-0222
2016
Requejo, H.S.Mantovani, M.S.M., Louro, V.H.A., Ribeiro, V.B., Requejo, H.S., Santos, R.P.Z. dos.Geophysical analysis of Catalano 1 alkaline carbonatite complex in Goias, Brazil.Geophysical Prospecting, Vol. 64, 1, pp. 216-227.South America, BrazilDeposit - Catalano 1
DS202006-0952
2020
Rericha, A.Thomas, R., Davidson, P., Rericha, A.Emerald from the Habachtal: new observations.Mineralogy and Petrology, Vol. 114, pp. 161-173.Europe, Austriaemerald

Abstract: The emerald mineralization in the Habachtal (Austria) is geologically and tectonically complex, and previous investigators have identified fluid inclusion evidence for a hydrothermal/metamorphic origin for the emeralds. In this paper we report the discovery of emeralds with a distinctly different inclusion population including melt inclusions, which demonstrates that at least some and probably most of the emerald mineralization in the Habachtal occurred from an extremely fluid-rich pegmatite-like aluminosilicate melt under supercritical conditions, at high temperatures and moderate pressures (~700 °C, 5 kbar). This conclusion is based on the presence of very highly-ordered graphite, and extremely water-rich melt inclusions in emerald. The Lorentz distribution of MgCO3 against the water concentration is a very robust proof for the supercritical state. We suggest that the purely metamorphic model, based on the extrapolation of fluid inclusion data to the regional metamorphic conditions (550 °C and 5 kbar) by some previous investigators are inconsistent with our finding of high-temperature indications (well-ordered graphite, high-temperature fluid inclusions and melt inclusions). This apparent conflict suggests a more complex situation and requires a re-investigation of the emerald genesis in the Habachtal deposit.
DS201112-0856
2011
Research and MarketsResearch and MarketsIndian gems and jewellery industry, Q3 2011.Research and Markets.com, Sept. 1, 1p.IndiaNews item - diamonds
DS201112-0857
2011
Research and MarketsResearch and MarketsChin a synthetic diamond industry report 2010-2011. * expensiveResearch and Markets.com, June 24, 1p. abstractChinaNews item - synthetics
DS201412-0735
2014
Research and MarketsResearch and MarketsPrecious metals mining in Botswana to 2020 - a focus on the diamond industry.Research and Markets.com, Before getting to excited the report purchase price is $ 1500. USAfrica, BotswanaReport on Botswana diamond industry
DS201606-1107
2016
Research in Applied GeophysicsResearch in Applied GeophysicsUniverity of Toron to has undertaken a project to put their Research in Applied Geophysics series on-line.https:// tspace.library. utoronto.ca /handle/1807/ 71876, onlineTechnologyGeophysics - not specific to diamonds
DS201412-0274
2014
Resentini, A.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
Resentini, A.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.
DS1993-0876
1993
Reshef, M.Landa, E., Thore, P., Reshef, M.Model based stack: a method for constructing an accurate zero-offsetsection for complex overburdensGeophysical Prospecting, Vol. 41, pp. 661-670GlobalGeophysics -experimental not practical, Overburden
DS1985-0489
1985
Reshetnikov, N.F.Nepsha, V.I., Naletov, A.M., Reshetnikov, N.F., Klyuev, YU.A.Effect of Carbon Defects on the Diamond Thermal Conductivity.(russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 284, No. 4, pp. 844-846RussiaDiamond Morphology
DS202106-0943
2021
Reshma, K.S.Illa, B., Reshma, K.S., Kumar, P., Srinagesh, D., Haldar, C., Kumar, S., Mandal, P.Pn tomography and anisotropic study of the Indian Shield and the adjacent regions.Tectonophysics, Vo. 813, 228932 23p. PdfIndiatomography

Abstract: High-resolution P-wave velocity and anisotropy structure of the hitherto elusive uppermost mantle beneath the Indian shield and its surrounding regions are presented to unravel the tectonic imprints in the lithosphere. We inverted high quality 19,500 regional Pn phases from 172 seismological stations for 4780 earthquakes at a distance range of 2° to 15° with a mean apparent Pn velocity of 8.22 km/s. The results suggest that the Pn velocity anomalies with fast anisotropic directions are consistent with the collision environments in the Himalaya, Tibetan Plateau, Tarim Basin, and Burmese arc regions. The higher Pn anomalies along the Himalayan arc explicate the subducting cold Indian lithosphere. The cratonic upper mantle of the Indian shield is characterized by Pn velocity of 8.12-8.42 km/s, while the large part of the central Indian shield has higher mantle-lid velocity of ~8.42 km/s with dominant anisotropic value of 0.2-0.3 km/s (~7.5%) suggesting the presence of mafic ‘lava pillow’ related to the Deccan volcanism. The impressions of the rifts and the mobile belts are conspicuous in the velocity anomaly image indicating their deep seated origin. The Pn anisotropy in the Indian shield exhibits a complex pattern and deviates from the absolute plate motion directions derived from the SKS study, demonstrating the presence of frozen anisotropy in the Indian lithospheric uppermost mantle, due to the large scale tectonic deformation after its breakup from the Gondwanaland. Whereas, Pn and SKS anisotropic observations are well consistent in Tarim basin, Tibetan regions, eastern Himalayan syntaxis and the Burmese arc. The modeled anisotropic Pn clearly manifests a lower velocity anomaly bounded by 85°E and 90°E ridges in the southern Bay of Bengal. Further, 85°E ridge spatially separates the BoB lithosphere into faster and slower regions consistent with the body wave tomography and free-air gravity observation.
DS200612-0630
2006
Resiberg, L.Jacob, D., Resiberg, L., Yaxley, G.Processes of mantle refertilization and modification.Goldschmidt Conference 16th. Annual, S5-05 theme abstract 1/8p. goldschmidt2006.orgMantleCraton
DS2002-1415
2002
Resichmann, T.Schaltz, M., Resichmann, T., Tait, J., Bachtadse, V., Bahlburg, H., Martin, U.The Early Paleozoic break up of northern Gondwana, new paleomagnetic andInternational Journal of Earth Sciences, Vol. 91, No. 5, Oct. pp. 838-49.GermanyTectonics, Gondwana
DS200412-0599
2004
Resifeld, R.Gaft, M., Resifeld, R., Panczer, G.Luminescence spectroscopy of minerals and materials.Springer, 300p. ISBN 3-540-21918-8 $ 130.00TechnologyBook - luminescence
DS2001-0027
2001
Resnick, J.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
DS1994-1449
1994
Resource Information UnitResource Information Unit1994-1995 edition of register of Australian miningResource Information Unit, approx. $ 260.00AustraliaBook -ad, Directory of mining companies
DS2000-0814
2000
Resource Information UnitResource Information UnitRegister of Australian Mining 2000/01Register of Australian Mining, pp. 100-110.AustraliaDiamond section, Exploration activities, companies
DS1994-1450
1994
Resource Information Unit Ltd. and Eyres ReedResource Information Unit Ltd. and Eyres ReedAustralian Diamond Handbook 1994... brief overview of activities andcompanies.Resource Information Unit Ltd. and Eyres Reed, 54p.AustraliaNews item -diamond companies and projects, Diamond companies in Australia
DS1997-0952
1997
Resource Map ServicesResource Map ServicesMining atlas of the world mineral industryResource Map Services, approx. 800.00 United StatesGlobalMap - CD ROM., Atlas
DS1996-1178
1996
Resource Science IncResource Science IncINCA 1.0 a mineral exploration database for PeruResource Science Inc, PeruDatabase -mineral records, CD-Rom ad
DS1985-0559
1985
Resources IndustryResources IndustryArgyle Now Producing 12% of World Diamond Output.. Mining Of the Pipe to Begin Late 1985.Resources Industry, Vol. 8, No. 2, PP. 8-10.Australia, Western AustraliaProduction, Mining Methods
DS2002-1327
2002
Resources Information UnitResources Information UnitRegister of African Mining 2002/1. CD-ROM and paper productResources Information Unit, [email protected], $575.00AfricaBook - as well as CD ROM, Mining directory, legal, contacts
DS2003-1157
2003
Resovsky, J.Resovsky, J., Trampert, J.Using probabilistic seismic tomography to test mantle velocity density relationshipsEarth and Planetary Science Letters, Vol. 215, 1-2, pp. 121-134.MantleGeophysics - seismics, tomography
DS200412-1656
2003
Resovsky, J.Resovsky, J., Trampert, J.Using probabilistic seismic tomography to test mantle velocity density relationships.Earth and Planetary Science Letters, Vol. 215, 1-2, pp. 121-134.MantleGeophysics - seismics, tomography
DS200512-1098
2004
Resovsky, J.Trampert, J.,Deschamps, F., Resovsky, J., Yuen, D.Probabilistic tomography maps chemical heterogeneities throughout the lower mantle.Science, Vol. 306, 5697, Oct 29, pp. 853-6.MantleTomography, geochemistry
DS201012-0675
2010
Reston, T.Scholfield, N., Stevenson, C., Reston, T.Magma fingers and host rock fluidization in the emplacement of sills.Geology, Vol. 38, 1, pp. 63-66.Africa, South AfricaKaroo Basin - not specific to diamonds - fluidization
DS1991-1375
1991
Reston, T.J.Pratt, T.L., Hauser, E.C., Hearn, T.M., Reston, T.J.Reflection polarity of the Midcrustal Surrency bright spot beneath southeastern Georgia. Testing the fluid hypothesisJournal of Geophysical Research, Vol. 96, No. B6, June 10, pp. 10, 145-10, 158GeorgiaGeophysics, Tectonics
DS2001-0909
2001
Reston, T.J.Perez-Gussinye, M., Reston, T.J.Rheological evolution during extension at nonvolcanic rifted margins: onset of serpentinization and develop..Journal of Geophysical Research, Vol. 106, No. 3, Mar. 10, pp. 3961-76.GondwanaTectonics - rifting continental breakup
DS200412-1543
2004
Reston, T.J.Phipps Morgan, J., Reston, T.J., Ranero, C.R.Contemporaneous mass extinctions, continental flood basalts, and impact signals are mantle plume induced lithospheric gas explosEarth and Planetary Science Letters, Vol. 217, 3, Jan. 15, pp. 263-284.MantlePlume
DS201502-0077
2014
Restrepo, J.J.Martens, U., Restrepo, J.J., Ordonez-Carmona, O., Correa-Martinez, A.M.The Tahami and Anaconda terranes of the Colombian Andes: missing links between South American and Mexican Gondwana margins.Journal of Geology, Vol. 122, Sept. pp. 507-530.South America, MexicoTectonics
DS1997-0953
1997
Restrepo-Pace, P.A.Restrepo-Pace, P.A., Ruiz, J., Cosca, M.Geochronology and neodymium isotopic dat a of Grenville age rocks in the ColombianAndes: new constraints..Earth and Planetary Science Letters, Vol. 150, No. 3-4, Aug., pp. 427-442ColombiaLate Proterozoic - early Paleozoic, Paleocontinents, Gondwana
DS201012-0623
2010
Restrepo-Pace, P.A.Restrepo-Pace, P.A., Cediel, F.Northern South America basement tectonics and implications for paleocontinental reconstructions of the Americas.Journal of South American Earth Sciences, Vol. 29, 4, Oct. pp, 764-771.South AmericaTectonics
DS1988-0057
1988
Retallack, G.J.Bestland, E.A., Retallack, G.J.Stages of soil development on carbonatite ash during early Miocene @Rusting a Island, KenyaGeological Society of America (GSA) Abstract Volume, Vol. 20, No. 3, February p. 143. abstractKenyaCarbonatite
DS1993-1298
1993
Retallack, G.J.Retallack, G.J.Classification of paleosols: discussion and replyGeological Society of America Bulletin, Vol. 105, No. 12, December pp. 1635-1637GlobalPaleosols, Classification
DS1993-1299
1993
Retallack, G.J.Retallack, G.J.Classification of paleosols: discussion and replyGeological Society of America Bulletin, Vol. 105, No. 12, December pp. 1635-1637.GlobalPaleosols, Classification
DS1996-1179
1996
Retallack, G.J.Retallack, G.J.Acid trauma at the Cretaceous Tertiary boundary in eastern MontanaGsa Today, Vol. 6, No. 5, May pp. 1-7MontanaK-T boundary, Catastrophic events
DS2001-1222
2001
Retelle, M.J.Weddle, T.K., Retelle, M.J.Deglacial history and relative sea level changes northern New England and adjacent Canada.Geological Society of America Special Paper, No. 351, 304p. $ 120.00 United StatesOntario, Quebec, MaineGeomorphology - not specific to diamonds
DS1995-1565
1995
Rether, R.Rether, R.Geochemical approaches for environmental engineering of metalsSpringer, 170p. approx. $ 100.00GlobalBook -ad, Environment -geochemical
DS1995-2019
1995
Retief, E.A.Walraven, F., Retief, E.A., Moen, H.F.G.Single zircon lead evaporation evidence for 2.77 Ga magmatism in northwesternTransvaal, South AfricaSouth Afri. Journal of Geology, Vol. 97, No. 2, pp. 107-113South AfricaGeochronology, Makoppa Dome
DS2000-0981
2000
Retief, E.A.Verwoerd, W.J., Retief, E.A., Prins, P.The Etanenberg alkaline complex, NamibiaJournal of African Earth Sciences, p. 86. abstract.NamibiaAlkaline rocks
DS201606-1108
2016
Reuber, G.Reuber, G., Kaus, B.J.P., Schmalholz, S.M., White, R.W.Nonlithostatic pressure during subduction and collision and the formation of (ultra) high pressure rocks.Geology, Vol. 44, 5, pp. 343-346.UHP - subduction

Abstract: The mechanisms that result in the formation of high-pressure (HP) and ultrahigh-pressure (UHP) rocks are controversial. The usual interpretation assumes that pressure is close to lithostatic, petrological pressure estimates can be transferred to depth, and (U)HP rocks have been exhumed from great depth. An alternative explanation is that pressure can be larger than lithostatic, particularly in continental collision zones, and (U)HP rocks could thus have formed at shallower depths. To better understand the mechanical feasibility of these hypotheses, we performed thermomechanical numerical simulations of a typical subduction and collision scenario. If the subducting crust is laterally homogeneous and has small effective friction angles (and is thus weak), we reproduce earlier findings that <20% deviation of lithostatic pressure occurs within a subduction channel. However, many orogenies involve rocks that are dry and strong, and the crust is mechanically heterogeneous. If these factors are taken into account, simulations show that pressures can be significantly larger than lithostatic within nappe-size, mechanically strong crustal units, or within a strong lower crust, as a result of tectonic deformation. Systematic simulations show that these effects are most pronounced at the base of the crust (at ?40 km), where pressures can reach 2-3 GPa (therefore within the coesite stability field) for millions of years. These pressures are often released rapidly during ongoing deformation. Relating metamorphic pressure estimates to depth might thus be problematic in mechanically heterogeneous crustal rock units that appear to have been exhumed in an ultrafast manner.
DS202012-2244
2020
Reuber, G.S.Reuber, G.S., Simons, F.J.Multi-physics adjoint modeling of Earth structure: combining gravimetric, seismic, and geodynamic inversions.GEM: International Journal on Geomathematics, open access 38p. PdfMantlegeophysics - magnetics

Abstract: We discuss the resolving power of three geophysical imaging and inversion techniques, and their combination, for the reconstruction of material parameters in the Earth’s subsurface. The governing equations are those of Newton and Poisson for gravitational problems, the acoustic wave equation under Hookean elasticity for seismology, and the geodynamics equations of Stokes for incompressible steady-state flow in the mantle. The observables are the gravitational potential, the seismic displacement, and the surface velocity, all measured at the surface. The inversion parameters of interest are the mass density, the acoustic wave speed, and the viscosity. These systems of partial differential equations and their adjoints were implemented in a single Python code using the finite-element library FeNICS. To investigate the shape of the cost functions, we present a grid search in the parameter space for three end-member geological settings: a falling block, a subduction zone, and a mantle plume. The performance of a gradient-based inversion for each single observable separately, and in combination, is presented. We furthermore investigate the performance of a shape-optimizing inverse method, when the material is known, and an inversion that inverts for the material parameters of an anomaly with known shape.
DS202103-0399
2021
Reuber, G.S.Piccolo, A., Kaus, B.J.P., White, R.W., Palin, R.M., Reuber, G.S.Plume - Lid interactions during the Archean and implications for the generation of early continental terranes.Gondwana Research, Vol. 88, pp. 150-168. 19p. PdfMantlegeodynamics

Abstract: Many Archean terranes are interpreted to have a tectonic and metamorphic evolution that indicates intra-crustal reorganization driven by lithospheric-scale gravitational instabilities. These processes are associated with the production of a significant amount of felsic and mafic crust, and are widely regarded to be a consequence of plume-lithosphere interactions. The juvenile Archean felsic crust is made predominantly of rocks of the tonalite-trondhjemite-granodiorite (TTG) suite, which are the result of partial melting of hydrous metabasalts. The geodynamic processes that have assisted the production of juvenile felsic crust, are still not well understood. Here, we perform 2D and 3D numerical simulations coupled with the state-of-the-art of petrological thermodynamical modelling to study the tectonic evolution of a primitive Archean oceanic plateau with particular regard on the condition of extraction of felsic melts. In our numerical simulations, the continuous emplacement of new, dry mafic intrusions and the extraction of the felsic melts, generate an unstable lower crust which drips into the mantle soon after the plume arrival. The subsequent tectonic evolution depends on the asthenosphere TP. If the TP is high enough (? 1500 ?C) the entire oceanic crust is recycled within 2 Myrs. By contrast at low TP, the thin oceanic plateau slowly propagates generating plate-boundary like features.
DS1989-1338
1989
Reuber, I.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
DS1993-0804
1993
Reuber, I.Kepezhinskas, P.K., Reuber, I., Tanaka, H., Miyashitam S.Zoned calc alkaline plutons in northeastern Kamchatka, Russia: Implications for the crustal growth in magmatic arcs.Mineralogy and Petrology, Vol. 49, pp. 147-174.RussiaAlkaline rocks, Ultramafics -general not specific
DS201902-0311
2018
Reudas, T.Reudas, T., Breuer, D.Isocrater impacts: conditions and mantle dynamical responses for different impactor types.Icarus, Vol. 306, 1, pp. 94-115.Mantleimpact craters

Abstract: Impactors of different types and sizes can produce a final crater of the same diameter on a planet under certain conditions. We derive the condition for such “isocrater impacts” from scaling laws, as well as relations that describe how the different impactors affect the interior of the target planet; these relations are also valid for impacts that are too small to affect the mantle. The analysis reveals that in a given isocrater impact, asteroidal impactors produce anomalies in the interior of smaller spatial extent than cometary or similar impactors. The differences in the interior could be useful for characterizing the projectile that formed a given crater on the basis of geophysical observations and potentially offer a possibility to help constrain the demographics of the ancient impactor population. A series of numerical models of basin-forming impacts on Mercury, Venus, the Moon, and Mars illustrates the dynamical effects of the different impactor types on different planets. It shows that the signature of large impacts may be preserved to the present in Mars, the Moon, and Mercury, where convection is less vigorous and much of the anomaly merges with the growing lid. On the other hand, their signature will long have been destroyed in Venus, whose vigorous convection and recurring lithospheric instabilities obliterate larger coherent anomalies.
DS201412-0910
2015
Reuesser, E.Tamen, J., Nkoumbou, C., Reuesser, E., Tchouda, F.Petrology and geochemistry of mantle xenoliths from Kapsiki Plateau ( Cameroon Volcanic Line): implications for lithospheric upwelling.Journal of African Earth Sciences, Vol. 101, pp. 119-134.Africa, CameroonXenoliths
DS1860-0523
1886
Reunert, T.Reunert, T.Diamond Mining at the CapeIn: Noble, J. Official Handbook of The Cape of Good Hope For, PP. 178-221.Africa, South Africa, Cape ProvinceDiamond mining
DS1860-0765
1892
Reunert, T.Reunert, T.The Diamond Mines of South Africa (1892)In: Kimberley, South Africa And International Exhibition, Lo, 64P.Africa, South AfricaHistory
DS1860-0811
1893
Reunert, T.Reunert, T.Diamonds and Gold in South AfricaCape Town: Juta, ; London: Sampson, Low, Marston And Co., 242P. SOUTH AFRICA DIAMOND FIELDS PP. 3-77.Africa, South AfricaHistory
DS1860-0953
1896
Reunert, T.Reunert, T.Comments on a Paper by Atherstone Entitled Kimberley and Its Diamonds. #1Geological Society of South Africa Transactions, Vol. 1, PP. 82-85.Africa, South Africa, Griqualand WestHistory, Geology
DS1910-0303
1912
Reunert, T.Reunert, T.Early Days on the Diamond FieldsMining Engineering Journal of South Africa 21ST. ANNIVERSARY VOLUME., Vol. 21A, PP. 209-213.South Africa, Cape Province, Kimberley AreaHistory
DS1860-0766
1892
Reunert, T.G.Reunert, T.G.Les Mines du Diamant du Cap, Traduit de l'anglais Par M.j. De Montmort et Suivi D'une Etude Mineralogique Par M. Couttolenc.Soc. Hist. Natur. (autun) Bulletin., No. 5, PP. 85-126.Africa, South Africa, Cape ProvinceGeology
DS1910-0373
1913
Reuning, E.Reuning, E.Eine Reise Langs der Kuste Luderitzbucht-swakopmundMitt. Deut. Schutzgeb., Vol. 26, No. 1, PP. 118-126.; MAP 1:400, 000.Southwest Africa, NamibiaGeology, Marine Diamond Placers
DS1920-0348
1927
Reuning, E.Reuning, E.More about the Alexander Bay FindMin. Ind. Magazine (johannesburg), Vol. 6, P. 269.South AfricaHistory, Marine Diamond Placers, Oyster Line
DS1920-0397
1928
Reuning, E.Reuning, E.The Discovery of the Namaqualand Diamonds #2Min. Ind. Magazine (johannesburg), Vol. 7, PP. 51-55; PP. 87-91; PP. 141-143; PP. 219-221; PP.South AfricaHistory, Marine Diamond Placers
DS1930-0077
1931
Reuning, E.Reuning, E.A Contribution to the Geology and Paleontology of the West Edge of Bushmanland. the Relations of the Tertiary Deposits And Surface Quartzites to the Dwyka and the Kimberlite Occurrences.Royal Society. STH. AFR. Transactions, Vol. 19, No. 3, PP. 215-232.South AfricaRelated Rocks
DS1930-0078
1931
Reuning, E.Reuning, E.The Pomona Quartzite and Oyster Horizon on the West Coast North of the Mouth of the Oliphants River, Cape Province.Royal Society. STH. AFR. Transactions, Vol. 19, No. 3, PP. 205-214.South Africa, Southwest Africa, NamibiaStratigraphy, Littoral Diamond Placers
DS1930-0079
1931
Reuning, E.Reuning, E.Der Ursprung der Kustendiamanten Sued und SuedwestafrikasNeues Jahrbuch f?r Mineralogie, BRAUNS SOUVENIR VOLUME, ALSO: INTAGLIO VO, Vol. 64, PP. 775-828.Southwest Africa, Namibia, South AfricaLittoral Diamond Placers
DS1930-0176
1934
Reuning, E.Reuning, E.The Composition of the Deeper Sediments of the Pipe at Banke,namaqualand and Their Relation to Kimberlite.Royal Society. STH. AFR. Transactions, Vol. 21, PP. 33-39.South AfricaStratigraphy, Petrography, Sedimentology
DS201312-0293
2013
ReuschGao, S.S., Liu, Reed, Yu, Massinque, Mdala, Moidaki, Mutamina, Atekwana, Ingate, ReuschSeismic arrays to study African Rift initiation.EOS Transaction of AGU, Vol. 94, 24, June 11, pp. 213-214.Africa, southern AfricaGeophysics - seismics
DS200912-0318
2009
Reusch, A.M.Huerta, A.D., Nyblade, A.A., Reusch, A.M.Mantle transition zone structure beneath Kenya and Tanzania: more evidence for a deep seated thermal upwelling in the mantle.Geophysical Journal International, Vol. 177, 3, pp. 1249-1255..Africa, Kenya, TanzaniaGeothermometry
DS201112-0858
2011
Reusch, A.M.Reusch, A.M., Nyblade, A.A., Tibi, R., Wiens, D.A., Shore, P.J., Bekoa, A., Tabod, C.T., Mnange, J.M.Mantle transition zone thickness beneath Cameroon: evidence for an upper mantle origin for the Cameroon Volcanic Line.Geophysical Journal International, Vol. 187, 3, pp.1146-1150.Africa, CameroonMantle zone
DS200912-0482
2009
Reusser, E.Mattson, H.B., Reusser, E.Incomplete mixing of silicate carbonatite magmas during the explosive eruption of Oldoinyo Lengai. September 2007.Goldschmidt Conference 2009, p. A849 Abstract.Africa, TanzaniaCarbonatite
DS201502-0112
2015
Reusser, E.Tamen, J., Nkoumbou, C., Reusser, E., Tchoua, F.Petrology and geochemistry of mantle xenoliths from the Kapsiki Plateau ( Cameroon Volcanic Line): implications for lithospheric upwelling.Journal of African Earth Sciences, Vol. 101, pp. 119-134.Africa, CameroonMetasomatism
DS201710-2216
2017
Reusser, E.Bosshard-Stadlin, S.A., Mattsson, H.B., Stewart, C., Reusser, E.Leaching of lava and tephra from the Oldoinyo Lengai volcano ( Tanzania): remobilization of fluorine and other potentially toxic elements in surface waters of the Gregory Rift.Journal of Volcanology and Geothermal Research, Vol. 322, pp. 14-25.Africa, Tanzaniadeposit - Oldoinyo Lengai

Abstract: Volcanic ash leachate studies have been conducted on various volcanoes on Earth, but few have been done on African volcanoes until now. Tephra emissions may affect the environment and the health of people living in this area, and therefore we conducted a first tephra (ash and lapilli sized) leachate study on the Oldoinyo Lengai volcano, situated in northern Tanzania. The recent explosive eruption in 2007-2008 provided us with fresh samples from the first three weeks of the eruption which were used for this study. In addition, we also used a natrocarbonatitic sample from the activity prior to the explosive eruption, as the major activity at Oldoinyo Lengai is natrocarbonatitic. To compare the leaching process affecting the natrocarbonatitic lavas and the tephras from Oldoinyo Lengai, the 2006 natrocarbonatitic lava flow was resampled 5 years after the emplacement and compared to the initial, unaltered composition. Special interest was given to the element fluorine (F), since it is potentially toxic to both humans and animals. A daily intake of fluoride (F?) in drinking water of > 1.5 mg/l can lead to dental fluorosis, and higher concentrations lead to skeletal fluorosis. For this reason, a guideline value for fluoride in drinking water was set by the WHO (2011) to 1.5 mg/l. However, surface waters and groundwaters in the Gregory Rift have elevated fluoride levels of up to 9.12 mg/l, and as a consequence, an interim guideline value for Tanzania has been set at 8 mg/l. The total concentration of fluorine in the samples from the natrocarbonatitic lava flow is high (3.2 wt%), whereas we observed a significant decrease of the fluorine concentration (between 1.7 and 0.5 wt%) in the samples collected three days and three weeks after the onset of the explosive 2007-08 eruption. However, the total amount of water-extractable fluoride is lower in the natrocarbonatitic lavas (319 mg/l) than in the nephelinitic tephra (573-895 mg/l). This is due to the solubility of the different F-bearing minerals. In the natrocarbonatites, fluorine exists predominantly in fluorite (CaF2), and in the early tephra as Na-Mg bearing salts such as neighborite (NaMgF3) and sellaite (MgF2). All these three minerals have very low solubility in water (16-130 mg/l). The later nephelinitic tephras contain surface coating of villiaumite (NaF), which is highly soluble (42,200 mg/l) in water and can thus release the fluoride more readily upon contact with water. Although there is still the need for further data and a more precise study on this topic in Tanzania, we can already draw a first conclusion that the intake of water during or directly following the deposition of the tephra is not advisable and should be avoided, whereas the release of fluoride from the lava flow has less influence on the river waters.-
DS1993-0696
1993
Reuteler, D.Honda, S., Yuen, D.A., Balachandar, S., Reuteler, D.Three-dimensional instabilities of mantle convection with multiple phasetransitionsScience, Vol. 259, February 26, pp. 1308-1311MantlePlumes, Tectonics
DS1995-1566
1995
Reuteler, D.M.Reuteler, D.M., Balachander, S., Yuen, D.A.The generation of localized toroidal velocity patches from plume dynamics:implications spinning microplatesEos, Vol. 76, No. 46, Nov. 7. p.F633-4. Abstract.MantlePlumes, Geodynamics, Tectonics
DS2000-0815
2000
Reuter, G.Reuter, G.A logical system of paleopedological termsCatena, Vol. 41, No. 1-3, Sept. pp. 93-109.GlobalClassification - soils
DS1990-1256
1990
Reuter, N.Rollig, G., Viehweg, M., Reuter, N.The ultramafic lamprophyres and carbonatites of Delitzsch/GDR. (in German)Zeitschrift fur Angewandte Geologie, (in German), Vol. 36, No. 2, February pp. 49-53GermanyCarbonatite
DS200412-0440
2003
ReutersReutersCongo mining officials question plunder report.Reuters, Oct. 30, 1/2p.Africa, Democratic Republic of CongoNews item
DS2000-0816
2000
Reutskii, V.N.Reutskii, V.N., Efimova, E.S., Sobolev, N.V.Isotopic composition of carbon in polycrystalline aggregates of diamond with inclusions of garnet/rutileRussian Geology and Geophysics, Vol.41,12,pp.1690-6., Vol.41,12,pp.1690-6.Russia, YakutiaDiamond inclusions, Deposit - Mir
DS2000-0817
2000
Reutskii, V.N.Reutskii, V.N., Efimova, E.S., Sobolev, N.V.Isotopic composition of carbon in polycrystalline aggregates of diamond with inclusions of garnet/rutileRussian Geology and Geophysics, Vol.41,12,pp.1690-6., Vol.41,12,pp.1690-6.Russia, YakutiaDiamond inclusions, Deposit - Mir
DS2002-1328
2002
Reutskii, V.N.Reutskii, V.N., Pokhilenko, N.P., Hall, A.E., Sobolev, N.V.Polygenous character of diamonds from kimberlites of the Snap lake region ( SlaveDoklady Earth Sciences, Vol. 386, 7, Sept-Oct.pp. 791-4.Northwest TerritoriesDiamond - morphology, Deposit - Snap Lake
DS201112-0944
2011
Reutskii, V.N.Shatski, V.S., Zedgenizov, D.A., Ragozin, A.L., Kalinina, V.V., Reutskii, V.N.Local variations in carbon isotopes and nitrogen contents in diamonds from placers of the northeastern portion of the Siberian Platform.Doklady Earth Sciences, Vol. 440, 1, pp.Russia, SiberiaGeochronology
DS201212-0670
2012
Reutskii, V.N.Smelov, A.P., Shatsky, V.S., Ragozin, A.L., Reutskii, V.N., Molotkov, A.E.Diamondiferous Archean rocks of the Olondo greenstone belt ( western Aldan-Stanovoy shield).Russian Geology and Geophysics, Vol. 53, pp. 1012-1022.RussiaDiamond - genesis
DS201312-0834
2012
Reutskii, V.N.Smelov, A.P., Shatsky, V.S., Ragozin, A.L., Reutskii, V.N., Molotkov, A.E.Diamondiferous Archean rocks of the Olondo greenstone belt ( western Aldan-Stanovoy shield).Russian Geology and Geophysics, Vol. 53, pp. 1012-1022.RussiaDiamond morphology
DS200612-1156
2006
Reutskiy, V.N.Reutskiy, V.N., Harte, B., Borzdov, Yu.M., Palyanov, Yu.N.Carbon and nitrogen effects during HTHP diamond crystallization.International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p. 139.TechnologyDiamond morphology
DS201512-1960
2015
Reutsky, V.Reutsky, V., Borzdov, Y., Palyanov, Y., Sokol, A., Izokh, O.Carbon isotope fractionation during experimental crystallization of diamond from carbonate fluid at mantle conditions.Contributions to Mineralogy and Petrology, Vol. 170, pp. 41-MantleHPHT

Abstract: We report first results of a systematic study of carbon isotope fractionation in a carbonate fluid system under mantle PT conditions. The system models a diamond-forming alkaline carbonate fluid using pure sodium oxalate (Na2C2O4) as the starting material, which decomposes to carbonate, CO2 and elementary carbon (graphite and diamond) involving a single source of carbon following the reaction 2Na2C2O4 ? 2Na2CO3 + CO2 + C. Near-liquidus behaviour of carbonate was observed at 1300 °C and 6.3 GPa. The experimentally determined isotope fractionation between the components of the system in the temperature range from 1300 to 1700 °C at 6.3 and 7.5 GPa fit the theoretical expectations well. Carbon isotope fractionation associated with diamond crystallisation from the carbonate fluid at 7.5 GPa decreases with an increase in temperature from 2.7 to 1.6 ‰. This trend corresponds to the function ?Carbonate fluid-Diamond = 7.38 × 106 T?2.
DS201904-0802
2017
Reutsky, V.Zedgenizov, D., Reutsky, V., Wiedenbeck, M.The carbon and nitrogen isotope characteristics of Type Ib-IaA cuboid diamonds from alluvial placers in the northeastern Siberian platform. MDPI Minerals, 14p. PdfRussiadiamond morphology

Abstract: Cuboid diamonds are particularly common in the placers of the northeastern Siberian platform, but their origin remains unclear. These crystals usually range in color from dark yellow to orange and, more interestingly, are characterized by unusual low aggregated nitrogen impurities (non-aggregated C-center), suggesting a short residence time and/or low temperatures at which they have been stored in the mantle. In order to track possible isotopic signature that could help deciphering cuboid diamond’s crystallization processes, ?¹³C values, ?¹?N values, and nitrogen concentrations have been determined in situ in three samples using secondary ion mass spectrometry (SIMS), whereas nitrogen aggregation states have been determined by FTIR spectroscopy. The samples fall out of the ?¹³C vs. ?¹?N field of canonical mantle composition. Different scales of carbon and nitrogen fractionation may produce the observed variations. Alternatively, mixing mantle and crustal material would obscure initial co-variations of ?¹³C values with ?¹?N or nitrogen content.
DS2003-1093
2003
Reutsky, V.N.Pokhilenko, N.P., McDonald, J.A., Sobolev, N.V., Reutsky, V.N., Hall, A.E.Crystalline inclusions and C isotope composition of diamonds from the Snap lake/King8 Ikc Www.venuewest.com/8ikc/program.htm, Session 3, AbstractNorthwest TerritoriesDiamonds - geochronology, Deposit - Snap Lake
DS200412-1564
2003
Reutsky, V.N.Pokhilenko, N.P., McDonald, J.A., Sobolev, N.V., Reutsky, V.N., Hall, A.E., Logvinova, A.M., Reimers, L.F.Crystalline inclusions and C isotope composition of diamonds from the Snap lake/King Lake kimberlite dyke system: evidence for a8 IKC Program, Session 3, AbstractCanada, Northwest TerritoriesDiamonds - geochronology Deposit - Snap Lake
DS200412-1566
2004
Reutsky, V.N.Pokhilenko, N.P., Sobolev, N.V., Reutsky, V.N., Hall, A.E., Taylor, L.A.Crystalline inclusions and C isotope ratios in diamonds from the Snap Lake/King Lake kimberlite dyke system: evidence of ultradeLithos, Vol. 77, 1-4, Sept. pp. 57-67.Canada, Northwest TerritoriesDiamond inclusions, Carbon isotopes
DS200512-1233
2003
Reutsky, V.N.Zedgenizov, D.A., Reutsky, V.N., Shatsky, V.S., Fedorova, E.N.Impurities and carbon isotope compositions of microdiamonds with extra faces from the Udachnaya kimberlite pipe.Russian Geology and Geophysics, Vol. 44, 9, pp. 834-41.Russia, YakutiaDiamond inclusions - Udachnaya
DS200712-0891
2007
Reutsky, V.N.Reutsky, V.N., Zedgenizov, D.A.Some specific features of genesis of microdiamonds of octahedral and cubic habit from kimberlites of the Udachanaya pipe inferred from carbon isotopes - defectRussian Geology and Geophysics, Vol. 48, pp. 299-304.Russia, YakutiaMicrodiamonds
DS200812-0951
2008
Reutsky, V.N.Reutsky, V.N., Borzdov, Yu.M., Palyanov, Yu.N.Carbon isotope fractionation associated with HPHT crystallization of diamond.Diamond and Related Materials, Vol. 17, 11, November pp. 1986-1989.TechnologyUHP
DS200812-0952
2008
Reutsky, V.N.Reutsky, V.N., Harte, B., EIMF, Borzdov, Y.M., Palyanov, Y.N.Monitoring diamond crystal growth, a combined experimental and SIMS study.European Journal of Mineralogy, Vol. 20, no. 3, pp. 365-374.TechnologyDiamond morphology
DS201412-0658
2014
Reutsky, V.N.Palyanov, Y.N., Bataleva, Y.V., Sokol, A.G., Borzdov, Y.M., Kupriyanov, I.N., Reutsky, V.N., Sobolev, N.V.Mantle slab interaction and redox mechanism of diamond formation.Proceedings of National Academy of Science USA, Vol. 110, 51, Dec. 17, pp.MantleUHP, deep carbon cycle
DS201502-0074
2015
Reutsky, V.N.Logvinova, A.M., Taylor, L.A., Fedorova, E.N., Yelisseyev, A.P., Wirth, R., Howarth, G., Reutsky, V.N., Sobolev, N.V.A unique Diamondiferous peridoite xenolith from the Udachnaya kimberlite pipe, Yakutia: role of subduction in diamond formation.Russian Geology and Geophysics, Vol. 56, 1, pp. 306-320.Russia, YakutiaDeposit - Udachnaya
DS201502-0092
2015
Reutsky, V.N.Reutsky, V.N., Palyanov, Yu.N., Borzdov, Yu.M., Sokol, A.G.Isotope fractionation of carbon during diamond cystallization in model systems.Russian Geology and Geophysics, Vol. 56, 1-2, pp. 239-244.TechnologyDiamond morphology
DS201610-1909
2016
Reutsky, V.N.Sobolev, N.V., Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L., Reutsky, V.N.Polycrystalline diamond aggregates from the Mir kimberlite pipe, Yakutia: evidence for mantle metasomatism.Lithos, in press available 10p.RussiaDeposit - Mir

Abstract: Polycrystalline diamond aggregates (boart, framesites, diamondites) have been widely studied but their origin is poorly understood. We report the results of a study in situ of two polished fragments of fine-grained (40-400 ?m size of individual diamond grains) dense polycrystalline diamond aggregates from the Mir pipe containing visible multiple interstitial garnet inclusions. They were analyzed for major and trace elements of inclusions and one of them — for ?13C and N abundance and isotopic composition of host diamonds. These aggregates are classified as variety IX by Orlov (1977). No cavities were observed in these samples. Sixty two irregular garnet grains and one clinopyroxene inclusion were detected and analyzed in sample Mr 832. Garnets are homogeneous within single grains but variable in Mg# [100Mg/(Mg + Fe)] from 60 up to 87 and CaO contents (3.3-5.3 wt.%) among grains with a trend to negative correlation. Low Cr (550-640 ppm) confirms eclogitic (E-type) paragenesis. High Na2O contents (5.2 wt.%) of a single pyroxene inclusion are additional evidence of eclogitic nature of this sample. Wide variations in trace elements (ppm) are characteristic for garnet grains: Sr (2.7-25.6), Y (9.7-14.1), Zr (15.6-38.7) and positive Eu anomaly is present. The ?13C of diamonds within studied sample is variable (? 6.4 ÷? 9.8 ‰) as well as N abundance (75-1150 ppm) and ?15N ? 27, ? 38, ? 58 ‰. The second peridotitic (U/P-type) sample Mr 838 contains eight inclusions of Mg-rich Cr-pyropes (Mg# ~ 85, Cr2O3 3.2-3.4 wt.%) and magnesite inclusion with 4.35 wt.% FeO and 1.73 wt.% CaO. Trace element content in pyropes is relatively uniform (ppm): Sr (0.4-1.6), Y (13.2-13.4) and Zr (13.0). We conclude that heterogeneous distribution of the trace elements among garnet grains in Mr 832 and magnesite presence in Mr 838 are indicative of the effects of mantle metasomatism and rapid crystallization shortly before the eruption of the kimberlite.
DS201612-2351
2016
Reutsky, V.N.Zedgenizov, D.A., Kalinina, V.V., Reutsky, V.N., Yuryeva, O.P., Rakhmanova, M.I.Regular cuboid diamonds from placers on the northeastern Siberian platform.Lithos, Vol. 265, pp. 125-137.Russia, SiberiaDiamond morphology

Abstract: Alluvial placers of the northeastern Siberian Platform are characterized by a specific diamond population: regular cuboids, forming a continuous color series from yellowish-green to yellow and dark orange. This is the first comprehensive study of a large number of cuboid diamonds focusing on their morphology, N content and aggregation state, photoluminescence, C isotopic composition and inclusions. The cuboids are cubic (i.e. nearly flat faced) to subrounded crystals; most of them are resorbed. The cathodolominescence images and the birefringence patterns show that many cuboid diamonds record deformation. The cuboid diamonds are characterized by unusual FTIR spectra with the presence of C- (single nitrogen atom) and A- (pair of neighbour nitrogen atoms) centers, and two centers of unknown origin, termed X and Y. The presence of single substitutional nitrogen defects (C centers) in all cuboid diamonds testifies either storage in the mantle at relatively cool conditions or formation just prior to eruption of their host kimberlites. The studied diamonds are also characterized by the presence of specific set of luminescence centers: N3, H3, S1, NVo and NV?, some of which are suggested to have formed during deformation subsequent to diamond growth. The cuboid diamonds show a wide range of carbon isotope compositions from mantle-like values towards strongly 13C depleted compositions (? 6.1 to ? 20.2‰ ?13C). Combined with the finding of an eclogitic sulfide inclusion, the light carbon isotope compositions link the formation of the studied cuboids to deeply subducted basic protoliths, i.e. former oceanic crust.
DS201703-0431
2017
Reutsky, V.N.Reutsky, V.N.Carbon isotope fractionation in models of diamond forming media under lithoscopic pressure temperature conditions. ***In RUSInstitute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Dsc. 252p. *** in RUS available pdfMantleDiamond - genesis
DS201801-0054
2017
Reutsky, V.N.Reutsky, V.N., Shiryaev, A.A., Titkov, S.V., Wiedenbeck, M., Zudina, N.N.Evidence for large scale fractionation of carbon isotopes and of nitrogen impurity during crystallization of gem quality cubic diamonds from placers of North Yakutia.Geochemistry International, Vol. 55, 11, pp. 988-999.Russia, Yakutiaalluvials

Abstract: The spatial distribution of carbon and nitrogen isotopes and of nitrogen concentrations is studied in detail in three gem quality cubic diamonds of variety II according to Orlov’s classification. Combined with the data on composition of fluid inclusions our results point to the crystallization of the diamonds from a presumably oxidized carbonate fluid. It is shown that in the growth direction ?13C of the diamond becomes systematically lighter by 2-3‰ (from -13.7 to -15.6‰ for one profile and from -11.7 to -14.1‰ for a second profile). Simultaneously, we observe substantial decrease in the nitrogen concentration (from 400-1000 to 10-30 at ppm) and a previously unrecognized enrichment of nitrogen in light isotope, exceeding 30‰. The systematic and substantial changes of the chemical and isotopic composition can be explained using the Burton-Prim-Slichter model, which relates partition coefficients of an impurity with the crystal growth rate. It is shown that changes in effective partition coefficients due to a gradual decrease in crystal growth rate describes fairly well the observed scale of the chemical and isotopic variations if the diamond-fluid partition coefficient for nitrogen is significantly smaller than unity. This model shows that nitrogen isotopic composition in diamond may result from isotopic fractionation during growth and not reflect isotopic composition of the mantle fluid. Furthermore, it is shown that the infra-red absorption at 1332 ?m-1 is an integral part of the Y-defect spectrum. In the studied natural diamonds the 1290 ?m-1 IR absorption band does not correlate with boron concentration.
DS201901-0069
2017
Reutsky, V.N.Reutsky, V.N., Kowalski, P.M., Palyanov, Y.N., EIMF, Weidenbeck, M.Experimental and theoretical evidence for surface induced carbon and nitrogen fractionation during diamond crystallization at high temperatures and high pressures.Crystals MDPI, Vol. 7, 7, 14p. Doi.org/ 10.3390/cryst7070190Russiadiamond morphology

Abstract: Isotopic and trace element variations within single diamond crystals are widely known from both natural stones and synthetic crystals. A number of processes can produce variations in carbon isotope composition and nitrogen abundance in the course of diamond crystallization. Here, we present evidence of carbon and nitrogen fractionation related to the growing surfaces of a diamond. We document that difference in the carbon isotope composition between cubic and octahedral growth sectors is solvent-dependent and varies from 0.7‰ in a carbonate system to 0.4‰ in a metal-carbon system. Ab initio calculations suggest up to 4‰ instantaneous 13C depletion of cubic faces in comparison to octahedral faces when grown simultaneously. Cubic growth sectors always have lower nitrogen abundance in comparison to octahedral sectors within synthetic diamond crystals in both carbonate and metal-carbon systems. The stability of any particular growth faces of a diamond crystal depends upon the degree of carbon association in the solution. Octahedron is the dominant form in a high-associated solution while the cube is the dominant form in a low-associated solution. Fine-scale data from natural crystals potentially can provide information on the form of carbon, which was present in the growth media.
DS201904-0773
2019
Reutsky, V.N.Reutsky, V.N., Palyanov, Yu.N., Wiedenbeck, M.Carbon isotope composition of diamond crystals grown via redox mechanism.Geochemistry International, Vol. 56, 13, pp. 1398-1404.Globaldiamond morphology

Abstract: We report the carbon isotope compositions of a set of diamond crystals recovered from an investigation of the experimental interaction of metal iron with Mg-Ca carbonate at high temperature and high pressure. Despite using single carbon source with ?13C equal to +0.2‰ VPDB, the diamond crystals show a range of ?13C values from -0.5 to -17.1‰ VPDB. Diamonds grown in the metal-rich part of the system are relatively constant in their carbon isotope compositions (from -0.5 to -6.2‰), whereas those diamonds recovered from the carbonate dominated part of the capsule show a much wider range of ?13C (from -0.5 to -17.1‰). The experimentally observed distribution of diamond’ ?13C using a single carbon source with carbon isotope ratio of marine carbonate is similar to that found in certain classes of natural diamonds. Our data indicate that the ?13C distribution in diamonds that resulted from a redox reaction of marine carbonate with reduced mantle material is hardly distinguishable from the ?13C distribution of mantle diamonds.
DS201904-0774
2017
Reutsky, V.N.Reutsky, V.N., Palyanov, Yu.N., Wiedenbeck, M.Evidence for large scale fractionation of carbon isotopes and of nitrogen impurity during crystallization of gem quality cubic diamonds from placers of North Yakutia.Geochemistry International, Vol. 55, 11, pp. 988-999.Russia, Yakutiadiamond morphology

Abstract: The spatial distribution of carbon and nitrogen isotopes and of nitrogen concentrations is studied in detail in three gem quality cubic diamonds of variety II according to Orlov’s classification. Combined with the data on composition of fluid inclusions our results point to the crystallization of the diamonds from a presumably oxidized carbonate fluid. It is shown that in the growth direction ?13C of the diamond becomes systematically lighter by 2-3‰ (from -13.7 to -15.6‰ for one profile and from -11.7 to -14.1‰ for a second profile). Simultaneously, we observe substantial decrease in the nitrogen concentration (from 400-1000 to 10-30 at ppm) and a previously unrecognized enrichment of nitrogen in light isotope, exceeding 30‰. The systematic and substantial changes of the chemical and isotopic composition can be explained using the Burton-Prim-Slichter model, which relates partition coefficients of an impurity with the crystal growth rate. It is shown that changes in effective partition coefficients due to a gradual decrease in crystal growth rate describes fairly well the observed scale of the chemical and isotopic variations if the diamond-fluid partition coefficient for nitrogen is significantly smaller than unity. This model shows that nitrogen isotopic composition in diamond may result from isotopic fractionation during growth and not reflect isotopic composition of the mantle fluid. Furthermore, it is shown that the infra-red absorption at 1332 ?m-1 is an integral part of the Y-defect spectrum. In the studied natural diamonds the 1290 ?m-1 IR absorption band does not correlate with boron concentration.
DS201904-0775
2017
Reutsky, V.N.Reutsky, V.N.,Kowalski, P.M., Palyanov, Yu.N., Wiedenbeck, M.Experimental and theoretical evidence for surface induced carbon and nitrogen fractionation during diamond crystallization at high temperatures and high pressures.MDPI Crystals, 14p. Russiadiamond morphology

Abstract: Isotopic and trace element variations within single diamond crystals are widely known from both natural stones and synthetic crystals. A number of processes can produce variations in carbon isotope composition and nitrogen abundance in the course of diamond crystallization. Here, we present evidence of carbon and nitrogen fractionation related to the growing surfaces of a diamond. We document that difference in the carbon isotope composition between cubic and octahedral growth sectors is solvent-dependent and varies from 0.7h in a carbonate system to 0.4h in a metal-carbon system. Ab initio calculations suggest up to 4h instantaneous 13C depletion of cubic faces in comparison to octahedral faces when grown simultaneously. Cubic growth sectors always have lower nitrogen abundance in comparison to octahedral sectors within synthetic diamond crystals in both carbonate and metal-carbon systems. The stability of any particular growth faces of a diamond crystal depends upon the degree of carbon association in the solution. Octahedron is the dominant form in a high-associated solution while the cube is the dominant form in a low-associated solution. Fine-scale data from natural crystals potentially can provide information on the form of carbon, which was present in the growth media.
DS201911-2565
2019
Reutsky, V.N.Soboelev, N.V., Logvinova, A.M., Tomilenko, A.A., Wirth, R., Bulbak, T.A., Lukyanova, L.I., Fedorova, E.N., Reutsky, V.N., Efimova, E.S.Mineral and fluid inclusions in diamonds from the Urals placers, Russia: evidence for solid molecular N2 and hydrocarbons in fluid inclusions.Geochimica et Cosmochimica Acta, Vol. 266, pp. 197-212.Russia, Uralsdiamond inclusions

Abstract: The compositions of mineral inclusions from a representative collection (more than 140 samples) of diamonds from the placer deposits in the Ural Mountains were studied to examine their compositional diversity. The overwhelming majority of rounded octahedral and dodecahedral stones typical of placers contain eclogitic (E-type) mineral inclusions (up to 80%) represented by garnets with Mg# 40-75 and Ca# 10-56, including the unique high calcic “grospydite” composition, omphacitic pyroxenes containing up to 65% of jadeite, as well as kyanite, coesite, sulfides, and rutile. Peridotitic (P-type) inclusions are represented by olivine, subcalcic Cr-pyrope, chrome diopside, enstatite and magnesiochromite that are typical for diamonds worldwide. Comparing the chemical composition of olivine, pyrope and magnesiochromite in diamonds of the Urals, north-east of the Siberian platform placers and Arkhangelsk province kimberlites show striking similarity. There are significant differences only in the variations of carbon isotopic composition of the diamonds from the placers of the Urals and north-east of the Siberian platform. One typical rounded dodecahedral diamond was found to contain abundant primary oriented submicrometer-sized (<3.0?µm) octahedral fluid inclusions identified by transmission electron microscopy, which caused the milky color of the entire diamond crystal. The electron energy-loss spectrum of a singular inclusion has a peak at ?405?eV, indicating that nitrogen is present. The Raman spectra with peaks at 2346-2350?cm?1 confirmed that nitrogen exists in the solid state at room temperature. This means that fossilized pressure inside fluid inclusions may be over 6.0 GPa at room temperature, so the diamond may be considered sublithospheric in origin. However, identification of unique fluid inclusions in one typical placer diamond allows one to expand the pressure limit to at least more than 8.0 GPa. The volatile components of four diamonds from the Urals placers were analyzed by gas chromatography-mass spectrometry (GC-MS). They are represented (rel. %) by hydrocarbons and their derivatives (14.8-78.4), nitrogen and nitrogenated compounds (6.2-81.7), water (2.5-5.5), carbon dioxide (2.8-12.1), and sulfonated compounds (0.01-0.96). It is shown that high-molecular-weight hydrocarbons and their derivatives, including chlorinated, nitrogenated and sulfonated compounds, appear to be stable under upper mantle P-T conditions. A conclusion is drawn that Urals placer diamonds are of kimberlitic origin and are comparable in their high E-type/P-type inclusion ratios to those from the northeastern Siberian platform and in part to diamonds of the Arkhangelsk kimberlite province.
DS201912-2818
2018
Reutsky, V.N.Reutsky, V.N., Palynaov, Yu.N., Wiedenbeck, M.Carbon isotope composition of diamond crystals grown via redox mechanism.Geochemistry International, Vol. 56, 13, pp. 1398-1404.Mantleredox

Abstract: We report the carbon isotope compositions of a set of diamond crystals recovered from an investigation of the experimental interaction of metal iron with Mg-Ca carbonate at high temperature and high pressure. Despite using single carbon source with ?13C equal to +0.2‰ VPDB, the diamond crystals show a range of ?13C values from -0.5 to -17.1‰ VPDB. Diamonds grown in the metal-rich part of the system are relatively constant in their carbon isotope compositions (from -0.5 to -6.2‰), whereas those diamonds recovered from the carbonate dominated part of the capsule show a much wider range of ?13C (from -0.5 to -17.1‰). The experimentally observed distribution of diamond’ ?13C using a single carbon source with carbon isotope ratio of marine carbonate is similar to that found in certain classes of natural diamonds. Our data indicate that the ?13C distribution in diamonds that resulted from a redox reaction of marine carbonate with reduced mantle material is hardly distinguishable from the ?13C distribution of mantle diamonds.
DS202011-2070
2020
Reutsky, V.N.Zemnukhov, A.L., Reutsky, V.N., Zedgenizov, D.A., Ragozin, A.L., Zhelonkin, R.Y., Kalinina, V.V.Subduction related population of diamonds in Yakutian placers, northeastern Siberian platform.Contributions to Mineralogy and Petrology, Vol. 175, 98 10.1007/s00410-020-01741-w 11p. PdfRussia, Yakutiadiamond crystallography

Abstract: The 35 paired diamond intergrowths of rounded colorless transparent and gray opaque crystals from the placers of northeastern Siberian Platform were investigated. Mineral inclusions (KFsp, Coe, E-Grt, Po) detected in studied samples belong to eclogitic paragenesis. The majority of studied samples have uniform ranges of nitrogen content (1126-1982 at. ppm) and carbon isotope composition (??16.8 to ??23.2 ‰). These characteristics pointing towards subducted material are possible sources for their genesis. Two samples consist of a gray opaque crystal with the subduction-related characteristics (?13C ca. ??21‰ and N ca. 1300 at. ppm) and a transparent crystal with low nitrogen content (412 and 29 at. ppm) and a heavy carbon isotopic composition (?13C ??4.2 and ??4.6‰) common for primary mantle range. The higher degree of nitrogen aggregation in the crystals with mantle-like characteristics testifies their longer storage in the mantle conditions. These samples reflect multistage diamond growth history and directly indicate the mixing of mantle and subduction carbon sources at the basement of subcontinental lithospheric mantle of northeastern Siberian Platform.
DS202202-0197
2022
Reutsky, V.N.Karaevangelou, M., Kopylova, M.G., Luo, Y., Pearson, G., Reutsky, V.N.Mineral inclusions in Lace diamonds and the mantle below the Kroonstad kimberlite cluster in South Africa.Contribution to Mineralogy and Petrology, Vol. 1777, 2, 10.1007/s00410-021-01880-8Africa, South Africadeposit - Lace

Abstract: We studied diamond inclusions in the 133 Ma Lace kimberlite of the Kroonstad Group II kimberlite cluster (Kaapvaal craton) to compare them to diamonds beneath the adjacent coeval Voorspoed kimberlite. The studied 288 Lace diamonds are mostly colorless dodecahedral Type IaAB. Based on diamond inclusions (DI), 38 Lace diamonds were classified as eclogitic (44%, 19 samples), peridotitic (35%, 15 samples), and websteritic (9%, 4 samples). The diamonds formed from mantle carbon (?13C?=?? 9.1 to ? 2.5 ‰ for 18 samples), with the exception of one eclogitic diamond (?13C?=?? 19.2 ‰). A rare zircon inclusion provides age constraints for the Lace eclogite protolith at 3.2?±?0.4 Ga (Lu-Hf model age) and Lace eclogite diamond formation at 188?±?37 Ma (U-Pb age). The eclogite protolith age suggests its formation contemporaneous with the lower crustal magmatism and metamorphism in the Central Kaapvaal craton, complementary to the tonalite-trondhjemite-granodiorite magmatism in the region and synchronous with the consolidation of the Eastern Kaapvaal Block. Two distinct kinds of eclogites are found to host Lace diamonds, (1) Fe-rich eclogites located at 160-190 km, and (2) more calcic-magnesian eclogites with mineral compositions identical to websteritic DIs, that derive from shallower lithospheric depths. Various thermobarometric methods applied to Lace diamonds and DIs constrain the Lace geotherm as reflecting a surface heat flow below or equal to 38 mW/m2 and a lithosphere thickness of at least 220 km, at the time of kimberlite eruption. These thermal parameters demonstrate an excellent match between the thermal state of the Voorspoed and Lace mantle segments that persisted from the Archean to Cretaceous times. The Lace peridotitic-to-eclogitic diamond ratio (5/4) does not differ much from the Voorspoed DI ratio (6/4), but a hot and spatially restricted carbonatitic metasomatism event affected the Voorspoed peridotitic mantle to create the majority of Voorspoed diamonds. The contrast in the mineralogy of DIs in Lace and Voorspoed diamonds highlights the very local (ca. 10 km) extent of the metasomatism and heating, as well as the variability of the diamond-forming processes at the same spatial scale.
DS1993-1300
1993
Reutter, K.J.Reutter, K.J., Scheuber, E., Wigger, P.J.Tectonics of the southern Central AndesSpringer Verlag, 300p. plus 3 maps, approx. $ 260.00Chile, Argentina, Bolivia, AndesTable of contents, Structure, tectonics, sedimentology, metallogeny
DS200912-0624
2009
Revalo, R.Jr.Revalo, R.Jr., McDonough, W.F., Luong, M.The K/U ratio of the silicate Earth: insights into mantle composition, structure and thermal evolution.Earth and Planetary Interiors, Vol. 278, 3-4, pp. 361-369.MantleGeothermometry
DS200912-0495
2009
RevenaughMercier, J.P., Bostock, M.G., Cassidy, J.F., Dueker, K., Gaherty, J.B., Garnero, E.J., Revenaugh, ZandtBody wave tomography of western Canada.Tectonophysics, Vol. 475, 2, pp. 480-492.Canada, Alberta, British Columbia, Northwest TerritoriesGeophysics - seismics
DS1994-1451
1994
Revenaugh, J.Revenaugh, J., Sipkin, S.A.Mantle discontinuity structure beneath ChinaJournal of Geophysical Research, Vol. 99, No. B11, Nov. 10, pp. 21, 911-928.ChinaMantle, Geophysics -seismics
DS1994-1452
1994
Revenaugh, J.Revenaugh, J., Sipkin, S.A.Seismic evidence for silicate melt atop the 410 km mantleNature, Vol. 369, No. 6480, June 9, pp. 474-476.MantleSilicates, Geophysics -seismics
DS1997-0954
1997
Revenaugh, J.Revenaugh, J., Meyer, R.Seismic evidence of partial melt within a possible ubiquitous low velcoity layer at the base of mantle.Science, Vol. 277, No. 5326, Aug. 1, pp. 670-672.MantleMelting
DS2001-0460
2001
Revenaugh, J.Havens, E., Revenaugh, J.A broadband seismic study of the lowermost mantle beneath Mexico: constraints on ultralow velocity zoneJournal of Geophysical Research, Vol. 106, No. 12, pp. 30,809-20.MexicoGeophysics, Density, tectonics - not specific to diamonds
DS2001-0987
2001
Revenaugh, J.Rost, S., Revenaugh, J.Seismic detection of rigid zone at the top of the coreScience, No. 5548, Nov. 30, pp. 1911-13.MantleGeophysics - seismics, Core - boundary
DS200412-1694
2004
Revenaugh, J.Rost, S., Revenaugh, J.Small scale changes of core mantle boundary reflectivity studied using core reflected PcP.Physics of the Earth and Planetary Interiors, Vol. 145, 1-4, pp. 19-36.MantleGeothermometry
DS200512-1182
2005
Revenaugh, J.Williams, Q., Revenaugh, J.Ancient subduction, mantle ecologite and the 300 km seismic discontinuity.Geology, Vol. 33, 1, pp. 1-4.MantleEclogite
DS200512-1183
2005
Revenaugh, J.Williams, Q., Revenaugh, J.Ancient subduction, mantle eclogite and the 300 km seismic discontinuity.Geology, Vol. 33, 1, Jan. pp. 1-4.MantleEclogite, subduction, coesite
DS200612-0612
2006
Revenaugh, J.Hutko, A.R., Lay, T., Garnero, E.J., Revenaugh, J.Seismic detection of folded, subducted lithosphere at the core mantle boundary.Nature, Vol. 441, 7091, May 18, pp. 333-336.MantleGeophysics - seismics
DS200812-0247
2008
Revenaugh, J.Courtier, A.M., Revenaugh, J.Slabs and shear wave reflectors in the mid mantle.Journal of Geophysical Research, Vol. 113, August 15, B08312MantleSubduction
DS200812-0497
2008
Revenaugh, J.Hutko, A.R., Lay, T., Revenaugh, J., Garnero, E.J.Anticorrelated seismic velocity anomalies from post perovskite in the lowermost mantle.Science, No. 5879, May 23, pp. 1070-1973.MantleGeophysics - seismics
DS200812-0740
2008
Revenaugh, J.Mercier, J-P., Bostock, M.G., Audet, P., Gaherty, J.B., Garnero, E.J., Revenaugh, J.The teleseismic signature of fossil subduction: northwestern Canada. (part of Lithoprobe)Journal of Geophysical Research, Vol. 113, B 04308Canada, Northwest TerritoriesGeophysics - seismics
DS201012-0128
2010
Revenaugh, J.Courtier, A.M., Gaherty, J.B., Revenaugh, J., Bostock, M.G., Gamero, E.J.Seismic anisotropy associated with continental lithosphere accretion beneath the CANOE array, northwestern Canada.Geology, Vol. 38, 10, pp. 887-890.Canada, Alberta, Northwest TerritoriesGeophysics - seismics
DS201012-0277
2010
Revenaugh, J.Hier-Majumder, S., Revenaugh, J.Relationship between the viscosity and topography of the ultralow velocity zone near the core mantle boundary.Earth and Planetary Science Letters, Vol. 299, 3-4, pp. 382-386.MantleGeophysics - seismics
DS201212-0743
2012
Revenaugh, J.Valdez, M.N., Wu, Z., Yu, Y.G., Revenaugh,J., Wentzcovitch, R.M.Thermoeleastic properties of ringwoodite: its relationship to the 520 seismic discontinuity.Earth and Planetary Science Letters, Vol. 351-352, pp. 115-122.MantleGeophysics - seismics
DS1994-1567
1994
Revenko, A.Sekerin, A.P., Menshagin, Yu.V., Lepin, V.S., Revenko, A.high pressureotassium picritic basalts of the Sayan region, near IrkutskDoklady Academy of Sciences USSR, Vol. 326, Oct. pp. 127-130.Russia, SiberiaCraton, Alkaline rocks
DS2002-1329
2002
Reverdatto, V.Reverdatto, V.High/ultrahigh pressure peridotites and pyroxenites from the Kokchetav collision zone, Kazakhstan.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.226.RussiaUHP mineralogy
DS201112-0859
2011
Reverdatto, V.Reverdatto, V.Comparison of the compositions of olivines and clinopyroxenes from mantle and crustal peridotites of collisional high pressure/ultrahigh pressure zones.Doklady Earth Sciences, Vol. 438, 1, pp. 705-710.MantleUHP
DS1993-1301
1993
Reverdatto, V.V.Reverdatto, V.V., Lepetukha, V.V., Kolobov, V.Yu.Contact effect of the Zerenda granites on the Berlyk suite of rocks in the Kokchetav anticlinorium.Russian Geology and Geophysics, Vol. 34, No. 12, pp. 117-124.RussiaMetasomatism
DS1995-1567
1995
Reverdatto, V.V.Reverdatto, V.V., Sheplev, V.S., Polyanskii, O.P.Burial metamorphism and evolution of rift troughs: a model approachPetrology, (QE 420 P4), Vol. 3, No. 1, Jan-Feb. pp. 31-37RussiaTectonics, Rifting
DS2002-1330
2002
Reverdatto, V.V.Reverdatto, V.V., Kolmogorov, Y.P., Parkhomenko, V.S., Selyatitsky, A.Y.Geochemistry of peridotites from the Kolchetav Massif, KazakhstanDoklady Earth Sciences, Vol. 386, 7, Sept-Oct.pp. 786-90.Russia, KazakhstanGeochemistry
DS2003-1158
2003
Reverdatto, V.V.Reverdatto, V.V., Korolyuk, V.N., Selyatitsky, A.Yu.Evidence of the existence of peraluminous clinopyroxene ( tschermakite) in garnetDoklady Earth Sciences, Vol. 391A, 6, July-August, pp. 896-99.Russia, KazakhstanPetrology
DS200412-1657
2003
Reverdatto, V.V.Reverdatto, V.V., Korolyuk, V.N., Selyatitsky, A.Yu.Evidence of the existence of peraluminous clinopyroxene ( tschermakite) in garnet pyroxenites from the Kokchetav Massif, KazakhsDoklady Earth Sciences, Vol. 391A, 6, July-August, pp. 896-99.Russia, KazakhstanPetrology
DS200412-1658
2004
Reverdatto, V.V.Reverdatto, V.V., Selyatitski, A.Yu.Chloritic rocks and chloritized basalts as plausible precursors of metamorphic peridotites and pyroxenites in the Kokchetav MassDoklady Earth Sciences, Vol. 394, 1, Jan-Feb. pp. 130-133.Russia, KazakhstanMetamorphism
DS200512-0900
2005
Reverdatto, V.V.Reverdatto, V.V., Selyatisky, A.Yu., Remizov, D.N., Khlestov, V.V.Geochemical distinctions between mantle and crustal high/ultrahigh pressure peridotites and pyroxenites.Doklady Earth Sciences, Vol. 400, 1, pp. 72-76.MantleUHP
DS200512-0901
2004
Reverdatto, V.V.Reverdatto, V.V., Selyatitsky, A.Y., Remizov, D.N., Khlestov, V.V.Geochemical distinctions between mantle and crustal high/ultrahigh pressure peridotites and pyroxenites.Doklady Earth Sciences, Vol. 400, 1, pp. 72-76.MantleGeochemistry
DS200612-1157
2006
Reverdatto, V.V.Reverdatto, V.V., Selyatitskii, A.Y.Olivine garnet olivine spinel and orthopyroxene metamorphic rocks of the Kokchetav Massif, northern Kazakhstan.Petrology, Vol. 13, 6, pp. 513-539.RussiaUHP
DS200812-0594
2008
Reverdatto, V.V.Korobeyniko, S.N., Polyansky, V.G., Babichev, A.V., Reverdatto, V.V.Computer modeling of underthrusting and subduction under conditions of gabbro eclogite transition in the mantle.Doklady Earth Sciences, Vol. 421, 1, pp. 724-728.MantleSubduction
DS200812-0953
2008
Reverdatto, V.V.Reverdatto, V.V., Selyatitskiy, A.Yu., Carswell, D.A.Geochemical distinctions between crustal and mantle derived peridotites/pyroxenites in high/ultrhigh pressure metamorphic complexes.Russian Geology and Geophysics, Vol. 49, pp. 73-90.Russia, KazakhstanKokchetav massif, UHP
DS201112-0935
2011
Reverdatto, V.V.Selyatitskii, A.Yu., Reverdatto, V.V.Comparison of the compositions of olivines and clinopyroxenes from mantle and crustal peridotites of collisional high pressure ultrahigh pressure zones.Doklady Earth Sciences, Vol. 438, 1, pp. 705-710.MantleUHP
DS201112-1095
2011
Reverdatto, V.V.Vrublevskii, V.V., Reverdatto, V.V., Izokh, A.E., Gertner, I.F., Yudin, D.S., Tishin, P.A.Neoproterozoic carbonatite magmatism of the Yenesei Ridge, central Siberia: 40AR39Ar geochronology of the Penchenga rock complex.Doklady Earth Sciences, Vol. 437, 2, pp. 443-448.Russia, SiberiaCarbonatite
DS201212-0563
2012
Reverdatto, V.V.Polansky, O.P., Korobeynikov, S.N., Babichev, A.V., Reverdatto, V.V.Formation and upwelling of mantle diapirs through the cratonic lithosphere: numerical thermomechanical modeling.Petrology, Vol. 20, 2, pp. 120-137.Russia, SiberiaMagmatism
DS201212-0631
2012
Reverdatto, V.V.Selyatitskii, A.Yu., Reverdatto, V.V.Comparison of the compositions of clinopyroxenes, garnets and spinels from mantle and crustal peridotites of collisional high pressure/ultrahigh pressure zones.Doklady Earth Sciences, Vol. 441, 2, pp.MantleUHP - Kokchetav
DS201212-0632
2012
Reverdatto, V.V.Selyatitskii, A.Yu., Reverdatto, V.V., Kuzmin, D.V., Sobolev, N.V.Minor elements in unusual olivines from high pressure peridotites of the Kokchetav Massif (Northern Kazakhstan).Doklady Earth Sciences, Vol. 445, 2, pp. 1015-1020.Russia, KazakhstanDeposit - Kokchetav
DS2003-0195
2003
Revering, C.Bush, D., Nel, F., Revering, C., Kirkley, M.Geostatistical methods employed in resource evaluation of the Snap Lake diamond8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractNorthwest TerritoriesKimberlite geology and economics, Deposit - Snap Lake
DS2003-0895
2003
Revering, C.McBean, D., Kirkley, M., Revering, C.Structural controls on the morphology of Snap Lake kimberlite dyke8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractNorthwest TerritoriesKimberlite geology and economics, Deposit - Snap Lake
DS1991-1520
1991
Revetta, F.Schoonmaker, A., Revetta, F.A detailed gravity survey of the Gouverneur Quadrangle in the northwestAdirondacks, northern New YorkGeological Society of America Abstracts, Vol. 23, No. 1, February p. 124GlobalGeophysics -gravity, Alaskite bodies
DS1992-1272
1992
Revetta, F.A.Revetta, F.A., Schoonmaker, A.Computer contoured Bouguer Gravity map of New York StateGeological Society of America (GSA) Abstract Volume, Vol. 24, No. 3, March p. 70. abstractGlobalGeophysics, Gravity
DS1996-1180
1996
Revetta, F.A.Revetta, F.A., Jock, S.A detailed gravity map of northern New YorkGeological Society of America (GSA) Abstracts, Vol. 28, No. 3, Feb. p. 93. abstractGlobalGeophysics -gravity
DS202202-0212
2021
Revillon, S.Roche, V., Leroy, S., Guillocheau, F., Revillon, S., Ruffet, G., Watremez, L., d'Acremont, E., Nonn, C., Vetel, W., Despinois, F.The Limpopo magma-rich transform margin, south Mozambique - pt. 2. Implications for the Gondwana breakup.Tectonics, e2021TC006914 Africa, Mozambiquegeophysics - seismics

Abstract: The rifted continental margins of Mozambique provide excellent examples of continental passive margins with a significant structural variability associated with magmatism and inheritance. Despite accumulated knowledge, the tectonic structure and nature of the crust beneath the South Mozambique Coastal Plain (SMCP) are still poorly known. This study interprets high-resolution seismic reflection data paired with data from industry-drilled wells and proposes a structural model of the Limpopo transform margin in a magma-rich context. Results indicate that the Limpopo transform margin is characterized by an ocean-continent transition that links the Beira-High and Natal valley margin segments and represents the western limit of the continental crust, separating continental volcano-sedimentary infilled grabens from the oceanic crust domain. These basins result from the emplacement of the Karoo Supergroup during a Permo-Triassic tectonic event, followed by an Early Jurassic tectonic and magmatic event. This latter led to the establishment of steady-state seafloor spreading at ca.156 Ma along the SMCP. A Late Jurassic to Early Cretaceous event corresponds to formation of the Limpopo transform fault zone. Which accommodated the SSE-ward displacement of Antarctica with respect to Africa. We define a new type of margin: the magma-rich transform margin, characterized by the presence of voluminous magmatic extrusion and intrusion coincident with the formation and evolution of the transform margin. The Limpopo transform fault zone consists of several syn-transfer and -transform faults rather than a single transform fault. The intense magmatic activity was associated primarily with mantle dynamics, which controlled the large-scale differential subsidence along the transform margin.
DS201609-1716
2016
Revitt, A.De Wit, M., Bhebhe, Z., Davidson, J., Haggerty, S.E., Hundt, P., Jacob, J., Lynn, M., Marshall, T.R., Skinner, C., Smithson, K., Stiefenhofer, J., Robert, M., Revitt, A., Spaggiari, R., Ward, J.Overview of diamonds resources in Africa.Episodes, Vol. 9, 2, pp. 198-238.AfricaDiamond resources - overview

Abstract: From the discovery of diamonds in South Africa in 1866 until the end of 2013, Africa is estimated to have produced almost 3.2 Bct out of a total global production of 5.03 Bct, or 63.6% of all diamonds that have ever been mined. In 2013 African countries ranked 2nd (Botswana), 3rd (DRC), 6th (Zimbabwe), 7th (Angola), 8th (South Africa), and 9th (Namibia), in terms of carat production and 1st (Botswana), 4th (Namibia), 5th (Angola), 6th (South Africa), 7th (Zimbabwe), and 9th (DRC), in terms of value of the diamonds produced. In 2013 Africa produced 70.6 Mct out of a global total of 130.5 Mct or 54.1%, which was valued at US$ 8.7 billion representing 61.5% of the global value of US$ 14.1 billion.
DS201312-0957
2013
Revitt, A.W.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
DS1900-0620
1908
Revue ScienceRevue ScienceLes Nouveaux Procedes D'extraction des Diamants de l'afrique Australe.Revue Science, Vol. 5, No. 10, Oct. 17TH, P. 498.Africa, South AfricaMining Engineering
DS1975-0549
1977
Rex, D.Kresten, P., Printzlau, I., Rex, D., Vartiainen, H., Woolley, A.New Ages of Carbonatite and Alkaline Ultramafic Rock from Southwest eden and Finland.Geol. Foren. Forhandl., Vol. 99, PP. 62-65.Sweden, Finland, ScandinaviaCarbonatite, Alnoite, Geochronology
DS1997-0357
1997
Rex, D.Foster, A., Ebinger, C., Rex, D.Tectonic development of the northern Tanzanian sector of the East African rift systemJournal of Geological Society, Vol. 154, No. 4, July pp. 689-699.TanzaniaTectonics, Rifting
DS1960-0776
1967
Rex, D.C.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
DS1975-0158
1975
Rex, D.C.Paul, D.K., Rex, D.C., Harris, P.G.Chemical Characteristics and Potassium-argon Ages of Indian KimberliteGeological Society of America (GSA) Bulletin., Vol. 86, No. 3, PP. 364-366.IndiaGeochronology, Geochemistry, Kimberlites
DS1980-0077
1980
Rex, D.C.Brueckner, H.K., Rex, D.C.Potassium-argon and Rubidium-strontium Geochronology and Strontium isotopic Study of the Alno Alkaline Complex Northeastern Sweden.Lithos, Vol. 13, No. 2, PP. 111-119.Sweden, ScandinaviaIsotope
DS1983-0388
1983
Rex, D.C.Larsen, L.M., Rex, D.C., Secher, K.The Age of Carbonatites, Kimberlites and Lamprophyres from Southern West Greenland: Recurrent Alkaline Magmatism During2500 Million Years.Lithos, Vol. 16, No. 3, PP. 215-221.GreenlandGeochronology, Related Rocks, Ivigtut, Fiskenaesset
DS1987-0403
1987
Rex, D.C.Lebas, M.J., Mian, I., Rex, D.C.Age and nature of carbonatite emplacement in North PakistanGeologische Rundschau, Vol. 76, No. 2, pp. 317-324PakistanCarbonatite
DS1991-0344
1991
Rex, D.C.Davies, G.R., Spriggs, A.J., Nixon, P.H., Rex, D.C.A non cognate origin for the Gibeon kimberlite megacryst suiteProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 63-65Southwest Africa, Namibia, South AfricaPetrography, Geochronology -isotope
DS1991-1755
1991
Rex, D.C.Turner, D.C., Rex, D.C.Volcaniclastic carbonatite at Kaluwe, Zambia: age and relations to sedimentary rocks in the Zambezi rift ValleyJournal of the Geological Society of London, Vol. 148, pt. 1, January pp. 13-16ZambiaCarbonatite, Petrography
DS1992-0909
1992
Rex, D.C.Larsen, L.M., Rex, D.C.A review of the 2500 MA span of alkaline ultramafic potassic and carbonatitic magmatism in West Greenland (Review)Lithos, Vol. 28, No. 3-6. November pp. 367-402GreenlandAlkaline rocks, Potassic rocks
DS1992-1127
1992
Rex, D.C.Nixon, P.H., Davies, G.R., Rex, D.C., Gray, A.Venezuelan kimberlitesJournal of Volcanology and geothermal research, Vol. 50, No. 1/2, April 15, pp. 101-116VenezuelaKimberlites, Occurrences
DS1994-1293
1994
Rex, D.C.O'Connor, P.J., Hogelsberger, H., Feely, M., Rex, D.C.Fluid inclusion studies, rare-earth element chemistry and age of hydrothermal fluid mineralization in w Ireland- link continental rifting?Institute of Mining and Metallurgy (IMM) Bulletins, Vol. 102, pp. B141-B148IrelandGeochemistry, Geochronology
DS1993-1302
1993
Rey, P.Rey, P.Seismic and tectono-metamorphic characters of the lower continental crust in Phanerozoic areas: a consequence of post-thickening extension.Tectonics, Vol. 12, No. 2, April pp. 580-590.MantlePhanerozoic, Geophysics -seismics
DS2001-0973
2001
Rey, P.Rey, P., Vanderhaeghe, O., Teyssier, C.Gravitational collapse of the continental crust: definition, regimes and modesTectonophysics, Vol. 342, No. 3-4, Dec. pp. 435-49.MantleGeophysics - gravity
DS200612-0266
2006
Rey, P.Coltice, N., Betrand, H., Ricard, Y., Rey, P.Global warming of the mantle at the origin of flood basalts over supercontinents.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 108, abstract only.MantleBasalts
DS200712-0842
2007
Rey, P.Phillips, B.R., Coltice, N., Bertrand, H., Ricard, Y., Rey, P.Supercontinental warming, plumes and mantle evolution.Plates, Plumes, and Paradigms, 1p. abstract p. A786.MantleMagmatism
DS200912-0121
2009
Rey, P.Coltice, N., Betrand, H., Rey, P., Jourdan, F.,Ricard, Y.Global warming of the mantle beneath continents back to the Archean.Gondwana Research, Vol. 15, 3-4, pp. 264-266.MantleGeothermometry
DS201312-0275
2013
Rey, P.Francois, C., Philippot, P., Rey, P., Rubatto, D., Moyen, J-F.Archean geodynamic: fingerprinting sagduction vs subduction processes.Goldschmidt 2013, AbstractMantleSagduction
DS201701-0012
2016
Rey, P.Ganne, J., Feng, X., Rey, P., De Andrade, V.Statistical petrology reveals a link between supercontinents cycle and mantle global climate.American Mineralogist, Vol. 101, pp. 2768-2773.MantleGeostatistics

Abstract: The breakup of supercontinents is accompanied by the emplacement of continental flood basalts and dike swarms, the origin of which is often attributed to mantle plumes. However, convection modeling has showed that the formation of supercontinents result in the warming of the sub-continental asthenospheric mantle (SCAM), which could also explain syn-breakup volcanism. Temperature variations during the formation then breakup of supercontinents are therefore fundamental to understand volcanism related to supercontinent cycles. Magmatic minerals record the thermal state of their magmatic sources. Here we present a data mining analysis on the first global compilation of chemical information on magmatic rocks and minerals formed over the past 600 million years: a time period spanning the aggregation and breakup of Pangea, the last supercontinent. We show that following a period of increasingly hotter Mg-rich magmatism with dominant tholeiitic affinity during the aggregation of Pangea, lower-temperature minerals crystallized within Mg-poorer magma with a dominant calc-alkaline affinity during Pangea disassembly. These trends reflect temporal changes in global mantle climate and global plate tectonics in response to continental masses assembly and dispersal. We also show that the final amalgamation of Pangea at ~300 Myr led to a long period of lithospheric collapse and cooling until the major step of Pangea disassembly started at ~125 Myr. The geological control on the geosphere magma budget has implications on the oxidation state and temperature of the Earth’s outer envelopes in the Phanerozoic and may have exerted indirect influence on the evolution of climate and life on Earth.
DS2003-1159
2003
Rey, P.F.Rey, P.F., Philippot, P., Thebaud, N.Contribution of mantle plumes, crustal thickening and greenstone blanketing to the 2.75Precambrian Research, Vol. 127, 1-2, Nov. pp. 43-60.MantleHot spots, tectonics
DS200412-1659
2003
Rey, P.F.Rey, P.F., Philippot, P., Thebaud, N.Contribution of mantle plumes, crustal thickening and greenstone blanketing to the 2.75 - 2.65 Ga global crisis.Precambrian Research, Vol. 127, 1-2, Nov. pp. 43-60.MantleHotspots, tectonics
DS200812-0954
2008
Rey, P.F.Rey, P.F., Coltice, N.Neoarchean lithospheric strengthening and the coupling of Earth's geochemical reservoirs.Geology, Vol. 36, 8., pp. 635-638.MantleTectonics, modeling
DS201505-0236
2015
Rey, P.F.Rey, P.F.The geodynamics of mantle melting.Geology, Vol. 43, 4, pp. 367-368.MantleMelting
DS202108-1308
2021
Rey, T.Rey, T., Leone, F., Defossez, S., Gherardi, M., Parat, F.Volcanic hazards assessment of Oldoinyo Lengai in a data scarcity context.Territorium, Vol. 28, (II) pp. 69-81. pdfAfrica, Tanzaniadeposit - Oldoinyo Lengai

Abstract: The objective of our study is to establish an assessment of four volcanic hazards in a country threatened by the eruption of the OlDoinyo Lengai volcano. The last major eruption dates back to 2007-2008 but stronger activity in 2019 has revived the memory of volcanic threats to the Maasai and Bantu communities and human activities (agro-pastoral and tourism). The methods chosen have had to be adapted to the scarce and incomplete data. The volcanic hazards and their probability of occurrence were analysed on the basis of data available in the scientific literature and were supplemented by two field missions combining geography and hydro-geomorphology. Our study enabled us to map the hazards of ash fall, lava flows, lahars and avalanches of debris. Each hazard was spatialised by being ascribed an intensity. They are sometimes synchronous with the eruption sometimes they occur several months or years after a volcanic eruption. The results are the first step towards developing a volcanic risk management strategy, especially for the pastoral communities living around Lengai and for the growing tourist activities in this area.
DS1920-0041
1920
Reyburn, S.W.Reyburn, S.W., Zimmerman, S.H.Diamonds in Arkansaw, 1920Engineering and Mining Journal, Vol. 109, No. 17, PP. 983-986.United States, Gulf Coast, ArkansasDiamond Occurrence, Geology
DS201710-2278
2017
Reyes, A.V.Wolfe, A.P., Reyes, A.V., Royer, D.L., Greenwood, D.R., Doria, G., Gagen, M.H., Siver, P.A., Westgate, J.A.Middle Eocene CO2 and climate reconstructed from the sediment fill of a subarctic kimberlite Maar.Geology , Vol. 45, 7, pp. 619-622.Canada, Northwest Territoriesdeposit - Giraffe

Abstract: Eocene paleoclimate reconstructions are rarely accompanied by parallel estimates of CO2 from the same locality, complicating assessment of the equilibrium climate response to elevated CO2. We reconstruct temperature, precipitation, and CO2 from latest middle Eocene (ca. 38 Ma) terrestrial sediments in the posteruptive sediment fill of the Giraffe kimberlite in subarctic Canada. Mutual climatic range and oxygen isotope analyses of botanical fossils reveal a humid-temperate forest ecosystem with mean annual temperatures (MATs) more than 17 °C warmer than present and mean annual precipitation ?4× present. Metasequoia stomatal indices and gas-exchange modeling produce median CO2 concentrations of ?630 and ?430 ppm, respectively, with a combined median estimate of ?490 ppm. Reconstructed MATs are more than 6 °C warmer than those produced by Eocene climate models forced at 560 ppm CO2. Estimates of regional climate sensitivity, expressed as ?MAT per CO2 doubling above preindustrial levels, converge on a value of ?13 °C, underscoring the capacity for exceptional polar amplification of warming and hydrological intensification under modest CO2 concentrations once both fast and slow feedbacks become expressed.
DS201712-2722
2017
Reyes, A.V.Reyes, A.V., Wolfe, A.P., Tierney, J.E., Silver, P.A., Royer, D.L., Greenwood, D.R., Buryak, S., Davies, J.H.F.L.Paleoenvironmental research on early Cenozoic sediment fills in Lac de Gras kimberlite pipes: progress and prospects.45th. Annual Yellowknife Geoscience Forum, p. 65 abstractCanada, Northwest Territoriesdeposit - Giraffe

Abstract: Several Lac de Gras kimberlite pipes host thick accumulations of stratified post-eruptive lacustrine sediment and peat. Given the range of Lac de Gras kimberlite emplacement ages, these fills - though rare - provide a unique sedimentary archive of paleoenvironments during the sustained Early Cenozoic “greenhouse” interval, in a high-latitude region otherwise devoid of Phanerozoic sediment cover. Extensive exploration drilling has provided a valuable window into this unique sedimentary record, which would have otherwise remained covered by Quaternary glacial deposits. Our focus to date has been multidisciplinary study of the Giraffe pipe sediment fill: an ~80 m-thick sequence of post-eruptive lacustrine silt overlain by peat, which paints a remarkable picture of a humid-temperate Middle Eocene forest ecosystem on the Canadian Shield. Post-eruptive chronology is provided by interbedded distal tephra horizons, likely sourced from Alaska, that have been dated by glass fission-track and zircon U-Pb techniques. Paleoclimate proxies derived from pollen, wood cellulose oxygen isotopes, and biomarkers converge on reconstructed mean annual temperatures >17 °C warmer than present, with mean winter temperatures above freezing, and mean annual precipitation ~4x present. Two independent reconstructions of CO2 from well preserved conifer foliage suggest that this warming occurred under relatively modest atmospheric CO2 concentrations of 430-630 ppm. These findings provide direct field-based evidence for dramatic past arctic warming at CO2 concentrations that were well within the range of projections under “business-as-usual” emissions scenarios, underscoring the capacity for exceptional polar amplification of climate change under modest CO2 concentrations once both fast and slow feedbacks processes become expressed. Our studies at Giraffe pipe also highlight the scientific value of archived exploration drill core in the Lac de Gras kimberlite field, particularly with respect to pipes that are unremarkable for the purpose of diamond exploration.
DS201812-2787
2018
Reyes, A.V.Buryak, S., Reyes, A.V., Siver, P.A., Li, L., Dufrane, S.A.Bulk organic geochemistry and U-Pb zircon geochronology of the Wombat sedimentary fill.2018 Yellowknife Geoscience Forum , p. 98-99. abstractCanada, Northwest Territoriesdeposit - Wombat

Abstract: The Wombat locality (64.73°N, 110.59°W) is a diamondiferous kimberlite in the Lac de Gras kimberlite field of Northwest Territories. Two drill cores, CH 93-29 and DDH 0-005, intersect the Wombat crater facies and include 195 m of well preserved, undisturbed lake sediment fill. Bulk sediment elemental analysis, C isotope composition, and Rock-Eval pyrolysis, together with inferences from microfossils, are used to characterize conditions of sedimentation and paleoenvironment in the maar lake. Bulk sediment C/N, hydrogen index (HI), and ?13C indicate material derived from C3 land plants dominates the sedimentary organic matter, with a minor algal contribution. The ?13C values range from -25.3 ‰ to -30.2 ‰ (average -26.6 ‰) and are typical for C3 land plants, with fluctuations in ?13C likely related to shifts in the proportions of land-derived material and algal organic matter. An overall trend of higher ?13C towards the top of the core suggests increasing autochthonous organic matter production. 18 samples analyzed by Rock-Eval pyrolysis all plot in the Type III kerogen field for HI vs. Tmax,with average Tmax values ~425 °C indicative of the low thermal maturity of organic matter. Total organic carbon (TOC) averages 3.6 wt.% and average total carbonate content is 14.1 wt.%, indicating bottom water anoxia and substantial carbonate input from weathering of overlying carbonate cover rocks, respectively. Together with well-preserved freshwater microfossils (e.g. diatoms, chrysophytes, synurophytes), the results indicate deposition in a non-marine setting. The age of the Wombat maar lake sediments is determined using MC-LA-ICP-MS U-Pb zircon geochronology from two distal rhyolitic tephra beds found in the core DDH 0-005, yielding a date of 82.97±0.60 Ma (MSWD = 1.7, n=18 of 33 grains analyzed). This minimum age suggests that Wombat kimberlite pipe emplacement occurred during the Late Cretaceous, with sedimentation in the maar beginning shortly thereafter. Though our geochronology is preliminary at this point, our findings from the Wombat pipe post-eruptive lake sediment fill provide direct evidence for a non-marine environment in the Lac De Gras area during the Late Cretaceous. Furthermore, microfossils in the Wombat pipe sediment fill likely include the oldest-known occurrence of freshwater diatoms.
DS202204-0519
2022
Reyes-Aldasoro, C.CChow, B.H.Y., Reyes-Aldasoro, C.CAutomatic gemstone classification using computer vision.MDPI, Vol. 12, 1, 21p.dor.org/10.3390/min12010060Globalgemstones

Abstract: This paper presents a computer-vision-based methodology for automatic image-based classification of 2042 training images and 284 unseen (test) images divided into 68 categories of gemstones. A series of feature extraction techniques (33 including colour histograms in the RGB, HSV and CIELAB space, local binary pattern, Haralick texture and grey-level co-occurrence matrix properties) were used in combination with different machine-learning algorithms (Logistic Regression, Linear Discriminant Analysis, K-Nearest Neighbour, Decision Tree, Random Forest, Naive Bayes and Support Vector Machine). Deep-learning classification with ResNet-18 and ResNet-50 was also investigated. The optimal combination was provided by a Random Forest algorithm with the RGB eight-bin colour histogram and local binary pattern features, with an accuracy of 69.4% on unseen images; the algorithms required 0.0165 s to process the 284 test images. These results were compared against three expert gemmologists with at least 5 years of experience in gemstone identification, who obtained accuracies between 42.6% and 66.9% and took 42-175 min to classify the test images. As expected, the human experts took much longer than the computer vision algorithms, which in addition provided, albeit marginal, higher accuracy. Although these experiments included a relatively low number of images, the superiority of computer vision over humans is in line with what has been reported in other areas of study, and it is encouraging to further explore the application in gemmology and related areas.
DS2000-0818
2000
Reyhaniyyih, I.Reyhaniyyih, I., KassimovaThe complex method of study the typomorphism of the chromospinellids from kimberlites.Igc 30th. Brasil, Aug. abstract only 1p.Russia, Yakutia, South AfricaGeochemistry, Deposit - Archangel
DS201912-2836
2019
Reynaold, E.Yong, W., Secco, R.A., Littleton, J.A.H., Silber, R.A., Reynaold, E.The iron invariance: implications for thermal convection in Earth's core.Geophysical Research Letters, Vol. 46, 20, pp. 11065-110670.Mantlegeothermometry

Abstract: Earth's magnetic field is produced by a dynamo in the core that requires motion of the fluid Fe alloy. Both thermal convection, arising from the transport of heat in excess of conducted heat, and compositional convection, arising from light element exsolution at the freezing inner core boundary, are suggested as energy sources. The contribution of thermal convection (possibly ranging from nothing to significant) depends on thermal conductivity of the outer core. Our experimental measurements of electrical resistivity of solid and liquid Fe at high pressures show that resistivity is constant along the pressure?dependent melting boundary of Fe. Using our derived thermal conductivity value at the inner core (freezing) boundary, we calculate the heat conducted in the liquid outer core and find that thermal convection is needed to carry additional heat through the outer core to match the heat extracted through the core?mantle boundary.
DS2002-0572
2002
ReynardGillet, P., Sautter, V., Harris, Reynard, Harte, KunzRaman spectroscopic study of garnet inclusions in diamonds from the mantle transition zone.American Mineralogist, Vol.87, 2-3, pp. 312-17.BrazilSpectroscopy - majoritic content, Deposit - Sao Luiz
DS1993-0121
1993
Reynard, B.Biellmann, C., Gillet, P., Guyot, F., Peyronneau, J., Reynard, B.Experimental evidence for carbonate stability in the earth's lower mantleEarth and Planetary Science Letters, Vol. 118, pp. 31-41MantleCarbon, Diamond inclusions
DS1998-1200
1998
Reynard, B.Querel, G., Reynard, B.Symmetry and disorder in garnets on the pyrope -majorite join from Cr3+luminescence spectroscopy.Geophysical research Letters, Vol. 25, No. 2, Jan. 15, pp. 195-198.GlobalPetrology, Garnet
DS200812-0955
2008
Reynard, B.Reynard, B., Hilairet, N., Daniel, I., Wang, Y.Rheology of serpentines, seismicity and mass transfer in subduction zone.Goldschmidt Conference 2008, Abstract p.A789.MantleSubduction
DS201606-1109
2016
Reynard, B.Reynard, B.Mantle hydration and Cl rich fluids in the subduction forearc.Progress in Earth and Planetary Science, Vol. 3, Apr. 28, P. 9-MantleSubduction

Abstract: In the forearc region, aqueous fluids are released from the subducting slab at a rate depending on its thermal state. Escaping fluids tend to rise vertically unless they meet permeability barriers such as the deformed plate interface or the Moho of the overriding plate. Channeling of fluids along the plate interface and Moho may result in fluid overpressure in the oceanic crust, precipitation of quartz from fluids, and low Poisson ratio areas associated with tremors. Above the subducting plate, the forearc mantle wedge is the place of intense reactions between dehydration fluids from the subducting slab and ultramafic rocks leading to extensive serpentinization. The plate interface is mechanically decoupled, most likely in relation to serpentinization, thereby isolating the forearc mantle wedge from convection as a cold, potentially serpentinized and buoyant, body. Geophysical studies are unique probes to the interactions between fluids and rocks in the forearc mantle, and experimental constrains on rock properties allow inferring fluid migration and fluid-rock reactions from geophysical data. Seismic velocities reveal a high degree of serpentinization of the forearc mantle in hot subduction zones, and little serpentinization in the coldest subduction zones because the warmer the subduction zone, the higher the amount of water released by dehydration of hydrothermally altered oceanic lithosphere. Interpretation of seismic data from petrophysical constrain is limited by complex effects due to anisotropy that needs to be assessed both in the analysis and interpretation of seismic data. Electrical conductivity increases with increasing fluid content and temperature of the subduction. However, the forearc mantle of Northern Cascadia, the hottest subduction zone where extensive serpentinization was first demonstrated, shows only modest electrical conductivity. Electrical conductivity may vary not only with the thermal state of the subduction zone, but also with time for a given thermal state through variations of fluid salinity. High-Cl fluids produced by serpentinization can mix with the source rocks of the volcanic arc and explain geochemical signatures of primitive magma inclusions. Signature of deep high-Cl fluids was also identified in forearc hot springs. These observations suggest the existence of fluid circulations between the forearc mantle and the hot spring hydrothermal system or the volcanic arc. Such circulations are also evidenced by recent magnetotelluric profiles.
DS2000-0622
2000
ReynoldsMartignole, J., Calvert, A.J., Friedman, R., ReynoldsCrustal evolution along a seismic section across the Grenville Province, western Quebec.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.291-306.QuebecGeophysics - seismics, Tectonics
DS202001-0022
2019
Reynolds, C.D.Jones, T.J., Reynolds, C.D., Boothroyd, S.C.Fluid dynamic induced break-up during volcanic eruptions. ( mentions kimberlite and carbonatite)Nature Communications, doi.org/10.1038/ s41467-019-11750-4 7p. pdf Mantlemelting

Abstract: Determining whether magma fragments during eruption remains a seminal challenge in volcanology. There is a robust paradigm for fragmentation of high viscosity, silicic magmas, however little is known about the fragmentation behaviour of lower viscosity systems—the most abundant form of volcanism on Earth and on other planetary bodies and satellites. Here we provide a quantitative model, based on experiments, for the non-brittle, fluid dynamic induced fragmentation of low viscosity melts. We define the conditions under which extensional thinning or liquid break-up can be expected. We show that break-up, both in our experiments and natural eruptions, occurs by both viscous and capillary instabilities operating on contrasting timescales. These timescales are used to produce a universal break-up criterion valid for low viscosity melts such as basalt, kimberlite and carbonatite. Lastly, we relate these break-up instabilities to changes in eruptive behaviour, the associated natural hazard and ultimately the deposits formed.
DS202007-1151
2019
Reynolds, C.D.Jones, T.J., Reynolds, C.D., Boothroyd, S.C.Fluid dynamics induced break up during volcanic eruptions.Nature Communications, Vol. 10, 1, 10.1038/s41467-019-11750-4.Mantlegeodynamics

Abstract: Determining whether magma fragments during eruption remains a seminal challenge in volcanology. There is a robust paradigm for fragmentation of high viscosity, silicic magmas, however little is known about the fragmentation behaviour of lower viscosity systems—the most abundant form of volcanism on Earth and on other planetary bodies and satellites. Here we provide a quantitative model, based on experiments, for the non-brittle, fluid dynamic induced fragmentation of low viscosity melts. We define the conditions under which extensional thinning or liquid break-up can be expected. We show that break-up, both in our experiments and natural eruptions, occurs by both viscous and capillary instabilities operating on contrasting timescales. These timescales are used to produce a universal break-up criterion valid for low viscosity melts such as basalt, kimberlite and carbonatite. Lastly, we relate these break-up instabilities to changes in eruptive behaviour, the associated natural hazard and ultimately the deposits formed.
DS2000-0412
2000
Reynolds, D.D.Hillis, R.R., Reynolds, D.D.The Australian stress mapJournal of Geological Society of London, Vol. 157, No. 5, Sept.pp.915-22.AustraliaMap - structure, Tectonics
DS1989-1265
1989
Reynolds, D.J.Reynolds, D.J., Schlische, R.W.Comparative studies of continental rift systemsGeological Society of America Abstract Volume, Vol. 21, No. 2, p. 61. (Abstract only)Appalachia, TanzaniaNewark Group eastern N.America and Lakes Tanganyika and, Tectonics
DS1950-0190
1954
Reynolds, D.L.Reynolds, D.L.Fluidization As a Geological Process and its Bearing on The problem of Intrusive Granites.American Journal of Science, Vol. 252, PP. 577-614.GlobalBreccia
DS1991-1447
1991
Reynolds, I.Roeder, P.L., Reynolds, I.Crystallization of chromite and chromium solubility in basaltic meltsJournal of Petrology, Vol. 32, pt. 5, pp. 909-934GlobalChromite -basalts, Experimental petrology
DS1983-0208
1983
Reynolds, I.M.Eales, H.V., Reynolds, I.M.Factors Influencing the Composition of Chromite and Magnetite in Some Southern African Rocks.Icam 81 Geological Society of South Africa Spec. Publishing, No. 7, PP. 5-20.South AfricaGeochemistry, Mineralogy
DS1985-0295
1985
Reynolds, J.H.Honda, M., Reynolds, J.H., Roedder, E.Noble Gases in Diamonds from Different LocationsEos, Vol. 66, No. 46, p. 1117. abstract onlyAustralia, Brazil, Zaire, South Africa, Arkansas, South AmericaBlank
DS1987-0298
1987
Reynolds, J.H.Honda, M., Reynolds, J.H., Roedder, E., Epstein, S.Noble gases in diamonds: occurrences of solarlike helium and neonJournal of Geophysical Research, Vol. 92, No. B12, November 10, pp. 12, 507-12, 522GlobalBlank
DS1987-0451
1987
Reynolds, J.H.McConnville, P., Reynolds, J.H.Cosmogenic Helium in Sierra Leone diamonds?Eos, Vol. 68, No. 44, November 3, p. 1514. abstract onlySierra LeoneNoble gases, Geochemistry
DS1989-0975
1989
Reynolds, J.H.McConville, P., Reynolds, J.H.Cosmogenic helium and volatile rich fluid in Sierra Leone alluvialdiamondsGeochimica et Cosmochimica Acta, Vol. 53, No. 9, September pp. 2365-2375Sierra LeoneGeochemistry, helium
DS1989-0976
1989
Reynolds, J.H.McConville, P., Reynolds, J.H.Cosmogenic helium and volatile rich mantle fluid in Sierra Leone diamonds #1Meteoritics, Vol. 24, No. 4, December, pp. 301-302Sierra LeoneGeochemistry, Isotope -helium
DS1989-0977
1989
Reynolds, J.H.McConville, P., Reynolds, J.H.Cosmogenic helium and volatile rich mantle fluid in Sierra Leone diamonds #252nd Annual Meeting Of The Meteoritical Society, Lpi Contribution, Vol. 712, p. 154. AbstractSierra LeoneGeochemistry, Isotope -helium
DS1991-1098
1991
Reynolds, J.H.McConville, P., Reynolds, J.H., Epstein, S., Roedder, E.Implanted 3He, 4He and Xe in further studies of diamonds from westernAustraliaGeochimica et Cosmochimica Acta, Vol. 55, pp. 1977-1989AustraliaLamproites, Argyle, Ellendale, noble gases, geochronology
DS1991-1416
1991
Reynolds, J.M.Reynolds, J.M.The need for recognized standards of applied geophysical software and the geophysical education of software usersComputers and Geosciences, Vol. 17, No. 8, pp. 1099-1104GlobalComputers, Program -geophysical software standards
DS1991-1128
1991
reynolds, P.Mengel, F., Rivers, T., reynolds, P.Lithotectonic elements and tectonic evolution of Torngat Orogen, SaglekFiord, northern Labrador.Canadian Journal of Earth Sciences, Vol. 28, pp. 1407-23.Labrador, Ungava, QuebecCraton, Tectonics
DS2002-0343
2002
Reynolds, P.Culshaw, N., Reynolds, P., Sinclair, G., Barr, S.Amphibole and mice40Ar 39Ar ages from the Kaipokok and Aillik domains, Makkovik Province, Labrador: towards a characterization of back arc processes.Canadian Journal of Earth Science, Vol.39,5, May, pp.749-64.LabradorPaleoproterozoic - mobile belt
DS1992-1732
1992
Reynolds, P.H.Zentille, M., Reynolds, P.H.Low temperature thermochronologyMineralogical Association of Canada short course Handbook, 225p. approx. $ 30.00GlobalGeochronology, thermochronology, case studies, Table of contents
DS1997-1000
1997
Reynolds, P.O.Schandelmeir, H., Reynolds, P.O.Paleogeographic Paleotectonic atlas of north eastern Africa, Arabia and adjacent areas.Balkema, 160p. $ 168.00 United States not owned just referencedGlobalAtlas, Lineaments
DS1990-1222
1990
Reynolds, R.L.Reynolds, R.L.A polished view of remagnetizationNature, Vol. 345, June 14, pp. 579-580GlobalPaleomagnetism, RemagnetisM.
DS1991-1347
1991
Reynolds, R.L.Phillips, J.D., Reynolds, R.L., Frey, H.Crustal structure interpreted from magnetic anomalies. (review)Reviews of Geophysics, Vol. 29, No. S pp. 416-427MantleTectonics, Geophysics -magnetics
DS1996-0599
1996
Reynolds, R.L.Harlan, S.S., Geissman, J.W., Snee, L.W., Reynolds, R.L.Late Cretaceous remagnetization of Proterozoic mafic dikes southern Highland Mountains southwest Montana -Ar40 Ar39Geological Society of America (GSA) Bulletin., Vol. 108, No. 6, June pp. 653-668.MontanaGeochronology, Paleomagnetics -Highland Mountains
DS2002-1331
2002
Reynolds, S.D.Reynolds, S.D., Coblentz, D.D., Hillis, R.R.Tectonic forces controlling the regional intraplate stress field in continental Australia: results from new finite element modeling.Journal of Geophysical Research, Vol. 107, 7, ETG 1, DOI 10.1029/2001BJ000408.AustraliaGeophysics - seismics, tectonic - model
DS200412-0831
2004
Reynolds, S.D.Hillis, R.R., Reynolds, S.D.In situ stress field of Australia.Hillis, R.R., Muller, R.D. Evolution and dynamics of the Australian Plate, Geological Society America Memoir, No. 372, pp. 41-48.AustraliaGeophysics - seismics
DS200412-1660
2004
Reynolds, S.D.Reynolds, S.D., Coblentz, D.D., Hillis, R.R.Influence of plate boundary forces on the regional intraplate stress field of continental Australia.Hillis, R.R., Muller, R.D. Evolution and dynamics of the Australian Plate, Geological Society America Memoir, No. 372, pp. 49-58.AustraliaGeophysics - seismics
DS1989-1266
1989
Reynolds, S.J.Reynolds, S.J., Spencer, J.E., Asmerom, Y., DeWitt, E., LaubachEarly Mesozoic uplift in west-central Arizona and southeastern CaliforniaGeology, Vol. 17, No. 3, March pp. 207-211Arizona, CaliforniaGreat Basin area, Proterozoic
DS202111-1781
2021
Rezende Fernandes, P.Rezende Fernandes, P., Tommasi, A., Vauchez, A., Pachero Neves, S., Nannini, F.The Sao Francisco cratonic root beneath the Neoproterozoic Brasilia belt ( Brazil): petrophysical data from kimberlite xenoliths.Tectonophysics, Vol. 816, 220011, 23p. PdfSouth America, Brazildeposit - Limeira-1, Indaia-1, Canastra-1

Abstract: Petrostructural analysis of 31 mantle xenoliths from three kimberlitic pipes intruding the Neoproterozoic Brasilia belt close to the southwestern margin of the São Francisco craton (SFC) reveals microstructures and compositions similar to those observed in cratonic roots worldwide. (1) The spinel-peridotites sampling the upper section of the lithospheric mantle have dominantly refractory modal and mineral compositions, whereas garnet-peridotites sampling the deep lithospheric mantle have more fertile compositions, consistent with those observed in cratonic roots worldwide. (2) The spinel-peridotites present a variation in microstructure from coarse-granular to coarse-porphyroclastic, but similar olivine crystallographic preferred orientations (CPO). (3) The garnet-peridotites have fine-porphyroclastic microstructures. (4) Many coarse-porphyroclastic spinel-peridotites display Fe-enrichment in olivine and pyroxenes, often associated with Ti-enrichment in pyroxenes or spinel and occurrence of modal phlogopite. (5) Equilibrium temperatures and pressures of garnet-peridotites are consistent with a cratonic geotherm, but equilibrium conditions of spinel-peridotites require a warmer geotherm. We interpret these observations as indicating that the xenoliths sample the SFC mantle root, which extends beneath the Brasilia belt, but was modified by reactive transport of the magmas forming the Alto Parnaiba Igneous Province (APIP) between 120 and 90 Ma. The APIP magmatism resulted in heterogeneous modal metasomatism, Fe enrichment, development of coarse-porphyroclastic microstructures in spinel peridotites and fine-porphyroclastic microstructures in garnet-peridotites, and moderate heating of the cratonic mantle root. These changes may produce a decrease in seismic velocities explaining the local weak negative anomaly observed in the lithospheric mantle beneath the APIP, which contrasts with the positive velocity anomalies characterizing the SFC mantle root in P-wave tomography models. However, reactive magma transport did not erase the olivine CPO. Comparison of the average seismic properties of the xenoliths with seismological data implies dominantly subhorizontal fossil flow directions and a non-negligible contribution of the cratonic root to teleseismic S-waves splitting.
DS200512-0626
2004
Reznitskii, L.Z.Levitskii, V.I., Salnikova, E.B., Kotov, A.B., Reznitskii, L.Z., Barash, I.G., et al.Age of formation of apocarbonate metasomites of the Sharyzhalgai Uplift of the Siberian Craton basement, southwestern Baikal region U - Pb baddeleyite, zirconDoklady Earth Sciences, Vol. 399A, 9, Nov-Dec. pp. 1204-1208.Russia, SiberiaGeochronology
DS201903-0520
2019
Reznitskii, L.Z.Ivanov, A.V., Levitskii, I.V., Levitskii, V.I., Corfu, F., Demonterova, E.I., Reznitskii, L.Z., Pavlova, L.A., Kamenetsky, V.S., Savatenkov, V.M., Powerman, V.I.Shoshonitic magmatism in the Paleoproterozoic of the south-western Siberian Craton: an analogue of the modern post-collisiion setting.Lithos, Vol. 328-329, pp. 88-100.Russiadeposit - Sharyzhalgay

Abstract: The Siberian Craton was assembled in a Paleoproterozoic episode at about 1.88?Ga by the collision of older blocks, followed at about 1.86?Ga by post-collisional felsic magmatism. We have found a set of extremely fresh mica-bearing lamprophyre-looking rocks within the Sharyzhalgay metamorphic complex of the south-western Siberian Craton. Zircon from these rocks yields a UPb TIMS age of 1864.7?±?1.8?Ma, which coincides perfectly with the peak of the post-collisional granite ages and postdates by ~15?Ma the peak of ages obtained for metamorphism. The same ages were reported earlier for a mafic dyke with ocean island basalt (OIB) geochemical signatures and a Pt-bearing mafic-ultramafic intrusion found in the same region. Mineralogy, major and trace element geochemistry and Sr-Nd-Pb isotopes show that the studied rocks (1) have shoshonitic affinity, (2) are hybrid rocks with mineral assemblages which could not be in equilibrium, (3) where derived by recycling of an Archean crustal source and (4) resemble post-collision Tibetan shoshonitic series. The genesis of these rocks is considered to be due to melting of crustal lithologies and metasomatized lithospheric mantle within a subducted slab. Some of the resulting melts ascended through the lithospheric column and fractionated to low-Mg absarokites, whereas other melts were contaminated by orthopyroxenitic mantle material and attained unusual high-Mg mafic compositions. According to our model, the post-collisional magmatism (shoshonite- and OIB-type) occurred due to upwelling of hot asthenosphere through a slab window, when the active collision ceased as a result of the slab break off and loss of the slab pull force. Overall, our study shows that in the Paleoproterozoic shoshonitic melts were emplaced within a similar tectonic setting as seen today in modern orogenic systems.
DS201312-0512
2013
Reznitskiy, L.Kovach, V.,Salnikova, E., Wang, K-L., Jahn, B-M., Chiu, H-Y., Reznitskiy, L., Kotov, A., Lizuka, Y., Chung, S-L.Zircon ages and Hf isotopic constraints on sources of clastic metasediments of the Slyudyansky high grade complex, southeastern Siberia: implication for continental growth and evolution of the Central Asian orogenic belt.Journal of Asian Earth Sciences, Vol. 62, pp. 18-36.Russia, SiberiaUHP, Geochronology
DS201112-0639
2011
RezvukhinMalkovets, V.G., Griffin, Pearson, Rezvukhin, O'Reilly, Pokhilenko, Garanin, Spetsius, LitasovLate metasomatic addition of garnet to the SCLM: Os-isotope evidence.Goldschmidt Conference 2011, abstract p.1395.RussiaUdachnaya, Daldyn
DS201212-0438
2012
Rezvukhin, D.I.Malkovets, V.G., Griffin, W.L., Pearson, N.J., Rezvukhin, D.I., Oreilly, S.Y., Pokhilenko, N.P., Garanin, V.K., Spetsius, Z.V., Litasov, K.D.Late metasomatic addition of garnet to the SCLM: Os-itope evidence.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractMantleMetasomatism
DS201212-0583
2012
Rezvukhin, D.I.Rezvukhin, D.I., Malkovets, V.G., Gibsher, A.A., Kuzmin, D.V., Griffin, W.L., Pokhilenko, N.P., O'Reilly, S.Y.Mineral inclusions in pyropes from some kimberlite pipes of Yakutia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Internationskaya
DS201605-0887
2016
Rezvukhin, D.I.Rezvukhin, D.I., Malkovets, V.G., Sharygin, I.S., Kuzmin, D.V., Litasov, K.D., Gibsher, A.A., Pokhilenko, N.P., Sobolev, N.V.Inclusions of Cr- and Cr-Nb-Rutile in pyropes from the Internationalnaya kimberlite pipe, Yakutia.Doklady Earth Sciences, Vol. 466, 2, Feb. pp. 173-176.Russia, YakutiaDeposit - International

Abstract: The results of study of rutile inclusions in pyrope from the Internatsionalnaya kimberlite pipe are presented. Rutile is characterized by unusually high contents of impurities (up to 25 wt %). The presence of Cr2O3 (up to 9.75 wt %) and Nb2O5 (up to 15.57 wt %) are most typical. Rutile inclusions often occur in assemblage with Ti-rich oxides: picroilmenite and crichtonite group minerals. The Cr-pyropes with inclusions of rutile, picroilmenite, and crichtonite group minerals were formed in the lithospheric mantle beneath the Mirnyi field during their joint crystallization from melts enriched in Fe, Ti, and other incompatible elements as a result of metasomatic enrichment of the depleted lithospheric mantle.
DS201605-0888
2016
Rezvukhin, D.I.Rezvukhin, D.I., Malkovets, V.G., Sharygin, I.S., Kuzmin, D.V., Litasov, K.D., Gibsher, A.A., Pokhilenko, N.P., Sobolev, N.V.Inclusions of crichonite group minerals in pyropes from the Internatsionalnaya kimberlite pipe, Yakutia.Doklady Earth Sciences, Vol. 466, 2, Feb. pp. 206-209.Russia, YakutiaDeposit - International
DS201610-1886
2016
Rezvukhin, D.I.Melkovets, V.G., Rezvukhin, D.I., Belousova, E.A., Griffin, W.L., Sharygin, I.S., Tretiakova, I.G., Pokhilenko, N.P., Sobolev, N.V.Cr-rich rutile: a powerful tool for diamond exploration.Lithos, in press available 8p.Russia, SiberiaDeposit - Internationalnaya

Abstract: Mineralogical studies and U-Pb dating have been carried out on rutile included in peridotitic and eclogitic garnets from the Internatsionalnaya pipe, Mirny field, Siberian craton. We also describe a unique peridotitic paragenesis (rutile + forsterite + enstatite + Cr-diopside + Cr-pyrope) preserved in diamond from the Mir pipe, Mirny field. Compositions of rutile from the heavy mineral concentrates of the Internatsionalnaya pipe and rutile inclusions in crustal almandine-rich garnets from the Mayskaya pipe (Nakyn field), as well as from a range of different lithologies, are presented for comparison. Rutile from cratonic mantle peridotites shows characteristic enrichment in Cr, in contrast to lower-Cr rutile from crustal rocks and off-craton mantle. Rutile with Cr2O3 > 1.7 wt% is commonly derived from cratonic mantle, while rutiles with lower Cr2O3 may be both of cratonic and off-cratonic origin. New analytical developments and availability of standards have made rutile accessible to in situ U-Pb dating by laser ablation ICP-MS. A U-Pb age of 369 ± 10 Ma for 9 rutile grains in 7 garnets from the Internatsionalnaya pipe is consistent with the accepted eruption age of the pipe (360 Ma). The equilibrium temperatures of pyropes with rutile inclusions calculated using Ni-in-Gar thermometer range between ~ 725 and 1030 °C, corresponding to a depth range of ca ~ 100-165 km. At the time of entrainment in the kimberlite, garnets with Cr-rich rutile inclusions resided at temperatures well above the closure temperature for Pb in rutile, and thus U-Pb ages on mantle-derived rutile most likely record the emplacement age of the kimberlites. The synthesis of distinctive rutile compositions and U-Pb dating opens new perspectives for using rutile in diamond exploration in cratonic areas.
DS201612-2320
2016
Rezvukhin, D.I.Malkovets, V.G., Rezvukhin, D.I., Belousova, E.A., Griffin, W.L., Sharygin, I.S., Tretiakov, I.G., Gibsher, A.A., O'Reilly, S.Y., Kuzmin, D.V., Litasov, K.D., Logvinova, A.M., Pokhilenko, N.P., Sobolev, N.V.Cr-rich rutile: a powerful tool for diamond exploration.Lithos, Vol. 265, pp. 304-311.Russia, SiberiaDeposit - Internationalskaya

Abstract: Mineralogical studies and U-Pb dating have been carried out on rutile included in peridotitic and eclogitic garnets from the Internatsionalnaya pipe, Mirny field, Siberian craton. We also describe a unique peridotitic paragenesis (rutile + forsterite + enstatite + Cr-diopside + Cr-pyrope) preserved in diamond from the Mir pipe, Mirny field. Compositions of rutile from the heavy mineral concentrates of the Internatsionalnaya pipe and rutile inclusions in crustal almandine-rich garnets from the Mayskaya pipe (Nakyn field), as well as from a range of different lithologies, are presented for comparison. Rutile from cratonic mantle peridotites shows characteristic enrichment in Cr, in contrast to lower-Cr rutile from crustal rocks and off-craton mantle. Rutile with Cr2O3 > 1.7 wt% is commonly derived from cratonic mantle, while rutiles with lower Cr2O3 may be both of cratonic and off-cratonic origin. New analytical developments and availability of standards have made rutile accessible to in situ U-Pb dating by laser ablation ICP-MS. A U-Pb age of 369 ± 10 Ma for 9 rutile grains in 6 garnets from the Internatsionalnaya pipe is consistent with the accepted eruption age of the pipe (360 Ma). The equilibrium temperatures of pyropes with rutile inclusions calculated using Ni-in-Gar thermometer range between ~ 725 and 1030 °C, corresponding to a depth range of ca ~ 100-165 km. At the time of entrainment in the kimberlite, garnets with Cr-rich rutile inclusions resided at temperatures well above the closure temperature for Pb in rutile, and thus U-Pb ages on mantle-derived rutile most likely record the emplacement age of the kimberlites. The synthesis of distinctive rutile compositions and U-Pb dating opens new perspectives for using rutile in diamond exploration in cratonic areas.
DS201806-1243
2018
Rezvukhin, D.I.Rezvukhin, D.I., Malkovets, V.G., Sharygin, I.S., Tretiakova, I.G., Griffin, W.L., O'Reilly, S.Y.Inclusions of crichtonite group minerals in Cr-pyropes from the Internationalnaya kimberlite pipe, Siberian craton: crystal chemistry, parageneses and relationships to mantle metasomatism.Lithos, Vol. 308, 1, pp. 181-195.Russiadeposit - International

Abstract: Cr-pyrope xenocrysts and associated inclusions of crichtonite-group minerals from the Internatsionalnaya kimberlite pipe were studied to provide new insights into processes in the lithospheric mantle beneath the Mirny kimberlite field, Siberian craton. Pyropes are predominantly of lherzolitic paragenesis (Cr2O3 2-6?wt%) and have trace-element spectra typical for garnets from fertile mantle (gradual increase in chondrite-normalized values from LREE to MREE-HREE). Crichtonite-group minerals commonly occur as monomineralic elongated inclusions, mostly in association with rutile, Mg-ilmenite and Cr-spinel within individual grains of pyrope. Sample INT-266 hosts intergrowth of crichtonite-group mineral and Cl-apatite, while sample INT-324 contains polymineralic apatite- and dolomite-bearing assemblages. Crichtonite-group minerals are Al-rich (1.1-4.5?wt% Al2O3), moderately Zr-enriched (1.3-4.3?wt% ZrO2), and are Ca-, Sr-, and occasionally Ba-dominant in terms of A-site occupancy; they also contain significant amounts of Na and LREE. T-estimates and chemical composition of Cr-pyropes imply that samples represent relatively low-T peridotite assemblages with ambient T ranging from 720 to 820°?. Projected onto the 35?mW/m2 cratonic paleogeotherm for the Mirny kimberlite field (Griffin et al., 1999b. Tectonophysics 310, 1-35), temperature estimates yield a P range of ~34-42?kbar (~110-130?km), which corresponds to a mantle domain in the uppermost part of the diamond stability field. The presence of crichtonite-group minerals in Cr-pyropes has petrological and geochemical implications as evidence for metasomatic enrichment of some incompatible elements in the lithospheric mantle beneath the Mirny kimberlite field. The genesis of Cr-pyropes with inclusions of crichtonite-group minerals is attributed to the percolation of Ca-Sr-Na-LREE-Zr-bearing carbonate-silicate metasomatic agents through Mg- and Cr-rich depleted peridotite protoliths. The findings of several potentially new members of the crichtonite group as inclusions in garnet extend existing knowledge on the compositions and occurrences of exotic titanates stable in the lithospheric mantle.
DS201906-1341
2019
Rezvukhin, D.I.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.
DS201911-2544
2019
Rezvukhin, D.I.Malkovets, V.G., Rezvukhin, D.I., Griffin, W.L., Tretiakova, I.G., Pearson, N.J., Gibsher, A.A., Belousova, E.A., Zedgenizov, D.A., O'Reilly, S.Y.Re-Os dating of sulfide inclusions in Cr-pyropes from the Upper Muna kimberlites.Goldschmidt2019, 1p. AbstractRussiadeposit - Upper Muna

Abstract: Archean cratons are underlain by highly depleted subcontinental lithospheric mantle (SCLM). However, there are extensive evidences that Archean SCLM has been extensively refertilized by metasomatic processes, with the addition of Fe, Ca, and Al to depleted protoliths. The distribution of sub-calcic Cr-rich garnets in the SCLM beneath the Siberian craton suggests (1) sub-calcic garnets and diamonds are metasomatic phases in the cratonic SCLM; (2) the distribution of both phases is laterally heterogeneous on relatively small scales and related to ancient structural controls [1]. Re-Os isotopic compositions of twenty six sulfide inclusions in lherzolitic Cr-pyropes from Upper Muna kimberlites have been determined by laser ablation MCICPMS. Most analysed sulfides (~92%) have very low Re/Os ratios (<0.07), and their Re-depletion ages (TRD) form three major peaks: 3.4-2.8, 2.2-1.8 and 1.4-1.2 Ga (±0.03 Ga, mean 2s analytical uncertainty). One sulfide give the oldest TRD age at 4 Ga. Our data suggest that refertilization of the highly depleted SCLM and the introduction of Cr-pyrope garnet occurred in several episodes. The oldest age of ca 4 Ga indicate on the beginning of the formation of the depleted SCLM of the Siberian Craton in Hadean time [2].
DS202004-0531
2020
Rezvukhin, D.I.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
Rezvukhin, D.I.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.
DS202105-0779
2021
Rezvukhin, D.I.Nikolenko, E.I., Sharygin, I.S., Rezvukhin, D.I., Malkovets, v.G., Tychkov, N.S., Pokhilenko, N.P.Sulfide-bearing polymineralic inclusions in mantle-derived garnets from lamprophyres of the Chompolo field, (Central Aldan, Siberian Craton).Doklady Earth Sciences, Vol. 497, pp. 300-304.Russia, Siberiadeposit - Chompolo

Abstract: Sulfide-bearing polymineralic inclusions in mantle-derived chromium pyrope garnets of lherzolite paragenesis from lamprophyres of the Chompolo field (Aldan shield, southern Siberian craton) have been studied. The inclusions are composed of either only sulfides or sulfides in association with other minerals (carbonates, silicates, oxides, etc.). The sulfide part of the inclusions is represented by up to four minerals. Among the sulfides, minerals rich in Cu and Ni have been found, whereas Fe sulfides (pyrrhotite, troilite) are absent. This distinguishes the inclusions studied from the majority of sulfide inclusions in mantle minerals and diamonds, as well as in mantle xenoliths from kimberlites. The formation of polymineralic inclusions in chromium garnets of the Chompolo field is attributed to the effect of a carbonate-silicate metasomatic melt/fluid on mantle peridotites, as evidenced by the mineral suite associated with the sulfides. The research results indicate significant differences in the nature of metasomatic processes that occurred in the lithospheric mantle of the southern and central parts of the Siberian craton.
DS202105-0787
2021
Rezvukhin, D.I.Rezvukhina, O.V., Skublov, S.G., Rezvukhin, D.I., Korsakov, A.V.Rutile in diamondiferous metamorphic rocks: new insight from trace element composition, mineral/fluid inclusions, and U-Pb-ID-TIMS dating.Lithos, Vol. 394-395, 7p. PdfRussia, Kazakhstandiamond inclusions

Abstract: This study highlights the usefulness of rutile when applied for reconstruction of the metamorphic evolution of ultrahigh-pressure rocks containing diamond. Within the diamondiferous kyanite gneiss (Kokchetav massif, Northern Kazakhstan), rutile shows three distinct textural positions: (i) rounded/irregular-shaped grains in the rock matrix; (ii) monomineralic inclusions in garnet, kyanite, quartz, and zircon; and (iii) grains in polyphase inclusions within garnet and kyanite porphyroblasts. High Nb (1990-3197 ppm) and relatively low Cr (404-703 ppm) concentrations in rutile indicate its metapelitic derivation. The Zr content in rutile varies from 480 to 798 ppm and the average temperature estimates yielded by the Zr-in-rutile geothermometer for 5 GPa are 880 °C. Rutile-hosted Zn-rich (up to 1.74 wt% ZnO) staurolite is interpreted as a record of the prograde metamorphic stage formed as a result of gahnite+pyrophyllite+diaspore breakdown at 0.3-0.8 GPa, 400-450 °C. Inclusions of diamond±CO2 ± carbonate±garnet in rutile originated near the peak of metamorphism (~5 GPa and ~ 880 °C). U-Pb ID-TIMS dating of a representative rutile separate yielded a concordant age of 519 ± 1.6 Ma that is younger than the previously estimated U-Pb crystallization ages of the peak metamorphic assemblages of the Kokchetav massif (528 ± 3 Ma). The obtained age represents the timing of cooling to the closure temperature for Pb diffusion in rutile (Tc; 420-640 °C). The cooling of the rocks from the peak temperatures to Tc occurred with the rates of 27-51 °C/Ma, whereas the exhumation rates (from 880 °C and 5 GPa to 420-640 °C and 0.5-1 GPa) were 1.3-1.5 cm/year. The peak temperature estimates as well as rapid cooling and exhumation rates reported here are in agreement with published data on zircon from similar diamondiferous Kokchetav gneisses. This work demonstrates that rutile provides a beneficial tool in studies dealing with reconstruction of the metamorphic evolution of diamondiferous rocks.
DS202204-0534
2022
Rezvukhin, D.I.Rezvukhin, D.I., Nikolenko, E.I., Sharygin, I.S., Rezvukhina, O.V., Chervyaovskaya, M.V., Korsakov, A.V.Cr-pyrope xenocrysts with oxide mineral inclusions from the Chompolo lamprophyres ( Aldan shield): insights into mantle processes beneath the southeastern Siberian craton.Mineralogical Magazine, Vol. 86, pp. 60-77.Russia, Siberialamproite

Abstract: Pyrope xenocrysts (N = 52) with associated inclusions of Ti- and/or Cr-rich oxide minerals from the Aldanskaya dyke and Ogonek diatreme (Chompolo field, southeastern Siberian craton) have been investigated. The majority of xenocrysts are of lherzolitic paragenesis and have concave-upwards (normal) rare earth element (REEN) patterns that increase in concentration from light REE to medium-heavy REE (Group 1). Four Ca-rich (5.7-7.4 wt.% CaO) pyropes are extremely low in Ti, Na and Y and have sinusoidal REEN spectra, thus exhibiting distinct geochemical signatures (Group 2). A peculiar xenocryst, s165, is the only sample to show harzburgitic derivation, whilst demonstrating a normal-to-weakly sinusoidal REEN pattern and the highest Zr (93 ppm) and Sc (471 ppm). Chromite-magnesiochromite, rutile, Mg-ilmenite and crichtonite-group minerals comprise a suite of oxide mineral inclusions in the pyrope xenocrysts. These minerals are characteristically enriched in Cr with 0.6-7.2 wt.% Cr2O3 in rutile, 0.7-3.6 wt.% in Mg-ilmenite and 7.1-18.0 wt.% in the crichtonite-group minerals. Complex titanates of the crichtonite group enriched in large ion lithophile elements (LILE) are high in Al2O3 (0.9-2.2 wt.%), ZrO2 (1.5-5.4 wt.%) and display a trend of compositions from the Ca-Sr-specific varieties to the Ba-dominant species (e.g. lindsleyite). In the pyrope xenocrysts the oxides coexist with silicates (clino- and orthopyroxene and olivine), hydrous silicates (talc, phlogopite and amphibole), carbonate (magnesite), sulfides (pentlandite, chalcopyrite, breakdown products of monosulfide and bornite solid solutions), apatite and graphite. P-T estimates imply the inclusion-bearing pyrope xenocrysts have been derived from low-temperature peridotite assemblages that resided at temperatures of ~600-800°C and a pressure range of ~25-35 kbar in the graphite stability field. Pyrope genesis is linked to the metasomatic enrichment of peridotite protoliths by Ca-Zr-LILE-bearing percolating fluid-melt phases containing significant volatile components. These metasomatic agents are probably volatile-rich melts or supercritical C-O-H-S fluids that were released from a Palaeo-subduction slab.
DS201910-2287
2019
Rezvukhina, O.V.Mikhailenko, D.S., Korsakov, A.V., Rezvukhina, O.V., Golovin, A.V., Sobolev, N.V.A find of coesite in diamond bearing kyanite eclogite from the Udachnaya kimberlite pipe, Siberian craton.Doklady Earth Sciences, Vol. 487, 2, pp. 925-928.Russia, Siberiadeposit - Udachnaya

Abstract: A find of coesite in a kyanite graphite-diamond-bearing eclogite xenolith from the Udachnaya-Vostochnaya kimberlite pipe is described in this paper. The coesite relics were found in intensely fractured garnet indicating some influence of the kimberlite melt, which is supported by the typical secondary mineral assemblage around this inclusion. These data indicate that shallower diamond-free coesite-grade rocks (2.7 GPa) underwent metamorphism distinct from diamond-bearing coesite eclogites (?4 GPa). The metasomatic alteration of rock as a result of the C-O-H fluid-rock interaction during diamond crystallization may be another possible reason for the absence of coesite in diamond-bearing xenoliths.
DS202008-1438
2019
Rezvukhina, O.V.Rezvukhina, O.V., Korsakov, A.V., Rezvukin, D.I., Zamyatin, D.A., Zelenovskiy, P.S., Greshnyakov, E.D., Shur, V.Y.A combined Raman spectroscopy, cathodoluminescence, and electron backscatter diffraction study of kyanite porphyroblasts from diamondiferous and diamond-free metamorphic rocks ( Kokchetav Massif).Journal of Raman Spectroscopy, 13p. PdfRussialuminescence

Abstract: A series of precise nondestructive analytical methods (Raman spectroscopy, cathodoluminescence, and EBSD—electron backscatter diffraction) has been employed to investigate the internal textures of kyanite porphyroblasts from diamondiferous and diamond?free ultrahigh?pressure metamorphic rocks (Kokchetav massif, Northern Kazakhstan). Such internal kyanite characteristics as twinning, radial fibrous pattern, and spotty zoning were identified by means of Raman and cathodoluminescence imaging, whereas an intergrowth of two kyanite crystals was distinguished only by Raman imaging. The EBSD analysis recorded an ~10-25° changing of orientations along the elongation in the investigated kyanite porphyroblasts. The absence of a radial fibrous pattern and a spotty zoning on the EBSD maps indicates that these textures are not related to variations in crystallographic orientation. The absence of clear zoning patterns (cores, mantles, and rims) on the Raman, cathodoluminescence, or EBSD maps of the kyanite porphyroblasts indicates the rapid single?stage formation of these porphyroblasts near the peak metamorphic conditions and the lack of recrystallization processes. The obtained results provide important implications for deciphering of mineral internal textures, showing that the data obtained by cathodoluminescence mapping can be clearly reproduced by Raman imaging, with the latter method occasionally being even more informative. This observation is of significant importance for the study of minerals that are unexposed on a thin section surface or Fe? and Ni?rich minerals that do not show luminescence emission. The combination of the Raman spectroscopic, cathodoluminescence, and EBSD techniques may provide better spatial resolution for distinguishing different domains and textural peculiarities of mineral than the selective application of individual approaches.
DS202101-0031
2020
Rezvukhina, O.V.Rezvukhina, O.V., Korsakov, A.V., Rezvukin, D.I., Mikhailenko, D.S., Zamyatin, D.A., Greshnyakov, E.D., Shur, V.Y.Zircon from diamondiferous kyanite gneisses of the Kokchetav massif: revealing growth stages using an integrated cathodluminescence- Raman spectroscopy- electron microprobe approach.Mineralogical Magazine, in press 28p. https://doi.org /10.1180/mgm.2020.95RussiaKokchetav
DS202105-0787
2021
Rezvukhina, O.V.Rezvukhina, O.V., Skublov, S.G., Rezvukhin, D.I., Korsakov, A.V.Rutile in diamondiferous metamorphic rocks: new insight from trace element composition, mineral/fluid inclusions, and U-Pb-ID-TIMS dating.Lithos, Vol. 394-395, 7p. PdfRussia, Kazakhstandiamond inclusions

Abstract: This study highlights the usefulness of rutile when applied for reconstruction of the metamorphic evolution of ultrahigh-pressure rocks containing diamond. Within the diamondiferous kyanite gneiss (Kokchetav massif, Northern Kazakhstan), rutile shows three distinct textural positions: (i) rounded/irregular-shaped grains in the rock matrix; (ii) monomineralic inclusions in garnet, kyanite, quartz, and zircon; and (iii) grains in polyphase inclusions within garnet and kyanite porphyroblasts. High Nb (1990-3197 ppm) and relatively low Cr (404-703 ppm) concentrations in rutile indicate its metapelitic derivation. The Zr content in rutile varies from 480 to 798 ppm and the average temperature estimates yielded by the Zr-in-rutile geothermometer for 5 GPa are 880 °C. Rutile-hosted Zn-rich (up to 1.74 wt% ZnO) staurolite is interpreted as a record of the prograde metamorphic stage formed as a result of gahnite+pyrophyllite+diaspore breakdown at 0.3-0.8 GPa, 400-450 °C. Inclusions of diamond±CO2 ± carbonate±garnet in rutile originated near the peak of metamorphism (~5 GPa and ~ 880 °C). U-Pb ID-TIMS dating of a representative rutile separate yielded a concordant age of 519 ± 1.6 Ma that is younger than the previously estimated U-Pb crystallization ages of the peak metamorphic assemblages of the Kokchetav massif (528 ± 3 Ma). The obtained age represents the timing of cooling to the closure temperature for Pb diffusion in rutile (Tc; 420-640 °C). The cooling of the rocks from the peak temperatures to Tc occurred with the rates of 27-51 °C/Ma, whereas the exhumation rates (from 880 °C and 5 GPa to 420-640 °C and 0.5-1 GPa) were 1.3-1.5 cm/year. The peak temperature estimates as well as rapid cooling and exhumation rates reported here are in agreement with published data on zircon from similar diamondiferous Kokchetav gneisses. This work demonstrates that rutile provides a beneficial tool in studies dealing with reconstruction of the metamorphic evolution of diamondiferous rocks.
DS202204-0534
2022
Rezvukhina, O.V.Rezvukhin, D.I., Nikolenko, E.I., Sharygin, I.S., Rezvukhina, O.V., Chervyaovskaya, M.V., Korsakov, A.V.Cr-pyrope xenocrysts with oxide mineral inclusions from the Chompolo lamprophyres ( Aldan shield): insights into mantle processes beneath the southeastern Siberian craton.Mineralogical Magazine, Vol. 86, pp. 60-77.Russia, Siberialamproite

Abstract: Pyrope xenocrysts (N = 52) with associated inclusions of Ti- and/or Cr-rich oxide minerals from the Aldanskaya dyke and Ogonek diatreme (Chompolo field, southeastern Siberian craton) have been investigated. The majority of xenocrysts are of lherzolitic paragenesis and have concave-upwards (normal) rare earth element (REEN) patterns that increase in concentration from light REE to medium-heavy REE (Group 1). Four Ca-rich (5.7-7.4 wt.% CaO) pyropes are extremely low in Ti, Na and Y and have sinusoidal REEN spectra, thus exhibiting distinct geochemical signatures (Group 2). A peculiar xenocryst, s165, is the only sample to show harzburgitic derivation, whilst demonstrating a normal-to-weakly sinusoidal REEN pattern and the highest Zr (93 ppm) and Sc (471 ppm). Chromite-magnesiochromite, rutile, Mg-ilmenite and crichtonite-group minerals comprise a suite of oxide mineral inclusions in the pyrope xenocrysts. These minerals are characteristically enriched in Cr with 0.6-7.2 wt.% Cr2O3 in rutile, 0.7-3.6 wt.% in Mg-ilmenite and 7.1-18.0 wt.% in the crichtonite-group minerals. Complex titanates of the crichtonite group enriched in large ion lithophile elements (LILE) are high in Al2O3 (0.9-2.2 wt.%), ZrO2 (1.5-5.4 wt.%) and display a trend of compositions from the Ca-Sr-specific varieties to the Ba-dominant species (e.g. lindsleyite). In the pyrope xenocrysts the oxides coexist with silicates (clino- and orthopyroxene and olivine), hydrous silicates (talc, phlogopite and amphibole), carbonate (magnesite), sulfides (pentlandite, chalcopyrite, breakdown products of monosulfide and bornite solid solutions), apatite and graphite. P-T estimates imply the inclusion-bearing pyrope xenocrysts have been derived from low-temperature peridotite assemblages that resided at temperatures of ~600-800°C and a pressure range of ~25-35 kbar in the graphite stability field. Pyrope genesis is linked to the metasomatic enrichment of peridotite protoliths by Ca-Zr-LILE-bearing percolating fluid-melt phases containing significant volatile components. These metasomatic agents are probably volatile-rich melts or supercritical C-O-H-S fluids that were released from a Palaeo-subduction slab.
DS202008-1438
2019
Rezvukin, D.I.Rezvukhina, O.V., Korsakov, A.V., Rezvukin, D.I., Zamyatin, D.A., Zelenovskiy, P.S., Greshnyakov, E.D., Shur, V.Y.A combined Raman spectroscopy, cathodoluminescence, and electron backscatter diffraction study of kyanite porphyroblasts from diamondiferous and diamond-free metamorphic rocks ( Kokchetav Massif).Journal of Raman Spectroscopy, 13p. PdfRussialuminescence

Abstract: A series of precise nondestructive analytical methods (Raman spectroscopy, cathodoluminescence, and EBSD—electron backscatter diffraction) has been employed to investigate the internal textures of kyanite porphyroblasts from diamondiferous and diamond?free ultrahigh?pressure metamorphic rocks (Kokchetav massif, Northern Kazakhstan). Such internal kyanite characteristics as twinning, radial fibrous pattern, and spotty zoning were identified by means of Raman and cathodoluminescence imaging, whereas an intergrowth of two kyanite crystals was distinguished only by Raman imaging. The EBSD analysis recorded an ~10-25° changing of orientations along the elongation in the investigated kyanite porphyroblasts. The absence of a radial fibrous pattern and a spotty zoning on the EBSD maps indicates that these textures are not related to variations in crystallographic orientation. The absence of clear zoning patterns (cores, mantles, and rims) on the Raman, cathodoluminescence, or EBSD maps of the kyanite porphyroblasts indicates the rapid single?stage formation of these porphyroblasts near the peak metamorphic conditions and the lack of recrystallization processes. The obtained results provide important implications for deciphering of mineral internal textures, showing that the data obtained by cathodoluminescence mapping can be clearly reproduced by Raman imaging, with the latter method occasionally being even more informative. This observation is of significant importance for the study of minerals that are unexposed on a thin section surface or Fe? and Ni?rich minerals that do not show luminescence emission. The combination of the Raman spectroscopic, cathodoluminescence, and EBSD techniques may provide better spatial resolution for distinguishing different domains and textural peculiarities of mineral than the selective application of individual approaches.
DS202101-0031
2020
Rezvukin, D.I.Rezvukhina, O.V., Korsakov, A.V., Rezvukin, D.I., Mikhailenko, D.S., Zamyatin, D.A., Greshnyakov, E.D., Shur, V.Y.Zircon from diamondiferous kyanite gneisses of the Kokchetav massif: revealing growth stages using an integrated cathodluminescence- Raman spectroscopy- electron microprobe approach.Mineralogical Magazine, in press 28p. https://doi.org /10.1180/mgm.2020.95RussiaKokchetav
DS202112-1946
2022
Rezvukin, D.I.Shatskiy, A., Bekhtenova, A., Arefiev, A.V., Podborodnikov, I.V., Vinogradova, Y.C., Rezvukin, D.I., Litasov, K.D.Solidus and melting of carbonated phlogopite peridotite at 3-6.5 Gpa: implications for mantle metasomatism.Gondwana Research, Vol. 101, 156-174. pdfRussiadeposit - Udachnaya

Abstract: It is well known that water significantly lowers mantle solidi. But it turns out this paradigm is not always true. Here, we studied the interaction of K-rich carbonate melts with the natural garnet lherzolite from the Udachnaya kimberlite (Russia) in the presence of water at 3.0-6.5 GPa, corresponding to depths of 100-200 km. We found that at ? 1100 °C, the metasomatic interaction consumes garnet, orthopyroxene, and melt to produce phlogopite ± K-richterite + magnesite ± dolomite. Besides, primary clinopyroxene is replaced by one with a lower amount of jadeite component. Thus, the addition of water to the K-rich carbonate melt, infiltrating the subcontinental lithospheric mantle, should yield its partial or complete disappearance accompanied by phlogopitization and carbonation. The studied systems have H2O/K2O = 2, like that in phlogopite, and therefore correspond to carbonated phlogopite peridotite under fluid-absent conditions. At 4.0-6.5 GPa, the solidus of carbonated phlogopite peridotite is controlled by the following reaction: phlogopite + clinopyroxene + magnesite = garnet + orthopyroxene + olivine + hydrous K-carbonatite melt, which is bracketed between 1100 and 1200 °C. At 3 GPa, the solidus temperature decreases to about 1050 °C presumably owing to the Ca-Mg exchange reaction, clinopyroxene + magnesite = orthopyroxene + dolomite, which stabilizes dolomite reacting with phlogopite at a lower temperature than magnesite. Our results suggest that the phlogopite- and carbonate-rich metasomatic vein networks, weakening rigid lithosphere and promoting continental rifting, could be formed as a result of infiltration of hydrous K-carbonatite melt at the base of subcontinental lithospheric mantle. Stretching and thinning of the cratonic lithosphere make geotherms warmer and shifts their intersections with the solidus of carbonated phlogopite peridotite to shallower depths. Consequently, the successive erosion of the continental lithosphere and ascent of the lithosphere-asthenosphere boundary during continental rifting should be accompanied by remelting of phlogopite-carbonate metasomes, upward percolation of K-rich melt, and its solidification at the front of the magmatic-metasomatic mantle system.
DS1994-1453
1994
Rhea, B.S.Rhea, B.S., Wheeler, R.L.Map showing large structures interpreted from geophysical dat a in the vicinity of New Madrid.United States Geological Survey (USGS) Map, No. MF 2264-B, C, D, E total $ 14.25MissouriGeophysics, Map -New Madrid zone
DS1994-1454
1994
Rhea, B.S.Rhea, B.S., Wheeler, R.L.Map showing large structures interpreted from geophysical dat a in hevicinity of New MadridUnited States Geological Survey (USGS), MF-2264 B, C.D, E.MissouriMap, Structure - Madrid
DS201312-0742
2013
Rheaume, G.Rheaume, G., Caron-Vuotari, M.The future of mining in Canada's north.Conference Board of Canada, 96p.Canada, Northwest Territories, NunavutEconomics
DS200612-0717
2006
Rhede, D.Koch-Mueller, M., Matsyuk, S.S., Rhede, D., Wirth, R., Khistina, N.Hydroxyl in mantle olivine xenocrysts from the Udachnaya kimberlite pipe.Physics and Chemistry of Minerals, Vol. 33, 4, pp. 276-287.RussiaMineral chemistry - Udachnaya
DS200912-0180
2009
Rhede, D.Dobrzhinetskaya, L.F., Wirth, R., Rhede, D., Liu, Z., Green, H.W.Phlogopite and quartz lamellae in diamond bearing diopside from marbles of the Kokchetav massif, Kazakhstan: exsolution or replacement reaction?Journal of Metamorphic Geology, Vol. 27, 9, pp. 607-620.Russia, KazakhstanDeposit - Kokchetav
DS201012-0151
2010
Rhede, D.Deon, F., Koch-Muller, M., Rhede, D., Wirth, R.Water and iron effect on the P-T-x coordinates of the 410 km discontinuity in the Earth upper mantle.Contributions to Mineralogy and Petrology, in press available, 14p.MantleUHP
DS201012-0161
2010
Rhede, D.Dobrzhinetskaya, L.F., Wirth, R., Rhede, D.Phlogopite and quartz lamellae in diamond bearing diopside from marbles of the Kochetav Massif, Kazakhstan, exsolution or replacement reaction.Journal of Metamorphic Geology, Vol. 27, 9, pp. 607-620.Russia, KazakhstanKochetav area
DS201112-0265
2011
Rhede, D.Deon, F., Koch-Muller, M., Rhede, D., Wirth, R.Water and iron effect on the P-T-x coordinates of the 410 km discontinuity in the Earth upper mantle.Contributions to Mineralogy and Petrology, Vol. 161, 4, pp. 653-666.MantlePetrology
DS201112-0621
2011
Rhede, D.Lucassen, F., Franz, G., Dulski, P., Romer, R.L., Rhede, D.Element and Sr isotope signatures of titanite as indicator of variable fluid composition in hydrated eclogite.Lithos, Vol. 121, 1-4, pp. 12-24.TechnologyMetamorphism
DS201112-0675
2011
Rhede, D.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
Rhede, D.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
DS201112-0677
2011
Rhede, D.Milke, R., Keller, L., Rhede, D.The behaviour of Mg, Fe and Ni during replacement of olivine by orthopyroxene: experiments relevant to mantle metasomatism.Mineralogy and Petrology, In press availableMantleMetasomatism
DS201212-0370
2012
Rhede, D.Konzett, J., Rhede, D., Frost, D.J.The high PT stability of apatite and Cl partioning between apatite and hydrous potassic phases in peridotite: an experimental study to 19 Gpa with implcations for the transport of P, Cl, and K in the upper mantle.Contributions to Mineralogy and Petrology, Vol. 163, 2, pp. 277-296.MantlePetrology - experimental
DS201504-0184
2015
Rhede, D.Berryman, E.J., Wunder, B., Wirth, R., Rhede, D., Schettler, G., Franz, G., Heinrich, W.An experimental study on K and Na in corporation in dravitic tourmaline and insight into the origin of Diamondiferous tourmaline from the Kokchetav Massif, Kazakhstan.Contributions to Mineralogy and Petrology, Vol. 169, 19p.Russia, KazakhstanDiamondiferous tourmaline

Abstract: Tourmaline was synthesized in the system MgO-Al2O3-B2O3-SiO2-KCl-NaCl-H2O from an oxide mixture and excess fluid at 500-700 °C and 0.2-4.0 GPa to investigate the effect of pressure, temperature, and fluid composition on the relative incorporation of Na and K in dravitic tourmaline. Incorporation of K at the X-site increases with pressure, temperature, and KCl concentration; a maximum of 0.71 K pfu (leaving 0.29 X-vacant sites pfu) was incorporated into K-dravite synthesized at 4.0 GPa, 700 °C from a 4.78 m KCl, Na-free fluid. In contrast, Na incorporation depends predominately on fluid composition, rather than pressure or temperature; dravite with the highest Na content of 1.00 Na pfu was synthesized at 0.4 GPa and 700 °C from a 3.87 m NaCl and 1.08 m KCl fluid. All synthesized crystals are zoned, and the dominant solid solution in the Na- and K-bearing system is between magnesio-foitite [?(Mg2Al)Al6Si6O18(BO3)3(OH)3OH] and dravite [NaMg3Al6Si6O18(BO3)3(OH)3(OH)], with the dravitic component increasing with the concentration of Na in the fluid. In the K-bearing, Na-free system, the dominant solid solution is between magnesio-foitite and K-dravite [KMg3Al6Si6O18(BO3)3(OH)3(OH)], with the K-dravitic component increasing with pressure, temperature, and the concentration of K in the fluid. The unit-cell volume of tourmaline increases with K incorporation from 1555.1(3) to 1588.1(2) Å3, reflecting the incorporation of the relatively large K+ ion. Comparison of our results to the compositional data for maruyamaite (K-dominant tourmaline) from the ultrahigh-pressure rocks of the Kokchetav Massif in Kazakhstan suggests that the latter was formed in a K-rich, Na-poor environment at ultrahigh-pressure conditions near the diamond-stability field.
DS2003-0575
2003
Rheinberger, G.Hell, A.J., Ramsay, W.R.H., Rheinberger, G., Pooley, S.The geology, age, mineralogy and near surface features of the Merlin kimberlites8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractAustraliaKimberlite geology and economics, Deposit - Merlin
DS201610-1840
2016
Rheinberger, G.Aravanis, T., Chen, J., Fuechsle, M., Grujic, M., Johnston, P., Kok, Y., Magaraggia, R., Mann, A., Mann, L., McIntoshm S., Rheinberger, G., Saxey, D., Smalley, M., van Kann, F., Walker, G., Winterflood, J.VK1 tm - a next generation airborne gravity gradiometer.ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 5p.TechnologyGradiometer

Abstract: The minerals exploration industry’s demand for a highly precise airborne gravity gradiometer has driven development of the VK1TM Airborne Gravity Gradiometer, a collaborative effort by Rio Tinto and the University of Western Australia. VK1TM aims to provide gravity gradient data with lower uncertainty and higher spatial resolution than current commercial systems. In the recent years of VK1TM development, there have been significant improvements in hardware, signal processing and data processing which have combined to result in a complete AGG system that is approaching competitive survey-ready status. This paper focuses on recent improvements. Milestone-achieving data from recent lab-based and moving-platform trials will be presented and discussed, along with details of some advanced data processing techniques that are required to make the most use of the data.
DS1991-1037
1991
Rhind, D.W.Maguire, D.J., Goodchild, M.F., Rhind, D.W.Geographic information systems: principles and applicationsJ.wiley Publ, 640p. 416p. 2 vols. set approx. $ 300.00 United StatesGlobalGeographic Information systems, Book-ad
DS1975-0170
1975
Rhodes, J.M.Rhodes, J.M.Major and Trace Element Chemistry of Peridotite Inclusions from the lashaine Volcano, Tanzania.Physics and Chemistry of the Earth, Vol. 9, PP. 545-550.Tanzania, East AfricaMineral Chemistry
DS1991-1417
1991
Rhodes, M.C.Rhodes, M.C., Thayer, C.W.Mass extinctions: ecological selectivity and primary productionGeology, Vol. 19, No. 9, September pp. 877-880GlobalBoundary Cretaceous/Tertiary, Extinction
DS2000-0666
2000
Rhyakhovskii, V.M.Mironov, Yu.V., Rhyakhovskii, V.M., Pustovoi, A.A.Strontium, neodymium, lead isotopic zoning in the world ocean and mantle plumes.Geochemistry International, Vol. 38, No.S1, pp. S20-7.MantleSuperplumes, Subduction
DS201709-2078
2017
R-NZhu, R-N, Ni, P., Ding, J-Y., Wang, D-Z., Ju, Y., Kang, N.Petrography, chemical composition, and Raman spectra of chrome spinel: constraints on the diamond potential of the no. 30 pipe kimberlite in Wafandian, North Chin a Craton.Ore Geology Reviews, in press available, 40p.Chinadeposit - No. 30 Wafangdian

Abstract: Conventional diamond exploration seldom searches directly for diamonds in rock and soil samples. Instead, it focuses on the search for indicator minerals like chrome spinel, which can be used to evaluate diamond potential. Chrome spinels are preserved as pristine minerals in the early Paleozoic (?465 Ma), hydrothermally altered, Group I No. 30 pipe kimberlite that intruded the Neoproterozoic Qingbaikou strata in Wafangdian, North China Craton (NCC). The characteristics of the chrome spinels were investigated by petrographic observation (BSE imaging), quantitative chemical analysis (EPMA), and Raman spectral analysis. The results show that the chrome spinels are mostly sub-rounded with extremely few grains being subhedral, and these spinels are macrocrystic, more than 500 µm in size. The chrome spinels also have compositional zones: the cores are classified as magnesiochromite as they have distinctly chromium-rich (Cr2O3 up to 66.56 wt%) and titanium-poor (TiO2 < 1 wt%) compositions; and the rims are classified as magnetite as they have chromium-poor and iron-rich composition. In the cores of chrome spinels, compositional variations are controlled by Al3+-Cr3+ isomorphism, which results in a strong Raman spectra peak (A1g mode) varying from 690 cm?1 to 702.9 cm?1. In the rims of chrome spinel, compositional variations result in the A1g peak varying from 660 cm?1 to 672 cm?1. The morphology and chemical compositions indicate that the chrome spinels are mantle xenocrysts. The cores of the spinel are remnants of primary mantle xenocrysts that have been resorbed, and the rims were formed during kimberlite magmatism. The compositions of the cores are used to evaluate the diamond potential of this kimberlite through comparison with the compositions of chrome spinels from the Changmazhuang and No. 50 pipe kimberlites in the NCC. In MgO, Al2O3 and TiO2 versus Cr2O3 plots, the chrome spinels from the Changmazhuang and No. 50 pipe kimberlites are mostly located in the diamond stability field. However, only a small proportion of chrome spinels from No. 30 pipe kimberlite have same behavior, which indicates that the diamond potential of the former two kimberlites is greater than that of the No. 30 pipe kimberlite. This is also supported by compositional zones in the spinel grains: there is with an increase in Fe3+ in the rims, which suggests that the chrome spinels experienced highly oxidizing conditions. Oxidizing conditions may have been imparted by fluids/melts that have a great influence on diamond destruction. Here, we suggest that chrome spinel compositions can be a useful tool for identifying the target for diamond potential in the North China Craton.
DS202202-0230
2022
R-ZZhu, R-Z, Ni, P., Wang, G-g., Ding, J-v., Kang, N.Temperature and oxygen state of kimberlite magma from the North China craton and their implication for diamond survival. Name change from Fuxian in Mengyin fieldsMineralium Deposita, Vol. 57, pp. 301-318. pdfChinadeposit - Wafangdiam

Abstract: The grade and morphological character of kimberlite-hosted diamonds were compared to crystallization temperature (T) and oxygen fugacity ( f O 2 ) estimated from groundmass spinels in six kimberlite pipes in the North China Craton (NCC). Crystallization temperatures calculated at an assumed pressure of 1 GPa are in the range of 1037-1395 °C, with a mean of 1182 °C. At these temperatures, the estimated f O 2 varies from 1.2 to 3.1 log units below the nickel-nickel oxide (NNO) buffer. Generally, individual kimberlite pipe shows a small variation of the T (50-100 °C) and f O 2 (0.4-0.6 log units), whereas different kimberlite pipes present great changes of T and f O 2 which can be up to 300 °C and 2 units respectively. The f O 2 of kimberlite magma shows a strong negative correlation with the diamond grade of kimberlite, suggesting that the f O 2 plays an important role in diamond resorption, whereas the T shows no relationship with the diamond grade, indicating the T plays no role in diamond resorption. The conditions of kimberlite crystallization ( f O 2 ) can be a useful parameter in evaluating diamond survival in diamond exploration.
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
 
 

You can return to the Top of this page


Copyright © 2024 Kaiser Research Online, All Rights Reserved