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 - Gi-Gq


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 - Gi-Gq
Posted/
Published
AuthorTitleSourceRegionKeywords
DS2003-0844
2003
GIALoupe, GIASmithsonian Institution exhibit showcases seven of the world's rarest diamondsThe Loupe, GIA, Summer p. 7 ( 1p.)GlobalDiamonds - notable, Steinmetz Pink, Millenium Star colo
DS200712-0359
2007
GIAGIADo you know your diamond? GIA launches its first U.S. National public awareness campaign.GIA, Oct. 12, 1p.United StatesNews item - Diamond Grading Reports
DS201807-1492
2018
GIAGIADr. D. Twitchen ( CVD Element Six) discussion using magnetic resonance and optical techniques to study how defects in diamond affect colour and electrical conductivity. Keynote speakerGIA Symposium , Oct. 7-9, Carlsbad CA United States, Californiasynthetics
DS201212-0240
2012
GIA LabGIA LabCVD synthetic diamonds identified in Hong Kong laboratory.G & G Brief, Vol. 3, 10, July 10, 1/4p.TechnologySynthetic diamonds
DS201112-0368
2011
GIA LaboratoryGIA LaboratoryLab examines a very large HPHT- treated diamond. 38.59 ctGems & Gemology Lab Notes, March 1, 1/4p.TechnologyDiamond - treatment
DS201608-1408
2016
GIA LibraryGIA LibraryRecommended reading & bibliographiesgia.edu/library, Available as a resourceTechnologyGIA Library
DS2001-1025
2001
Giacomelli, L.Scandone, R., Giacomelli, L.The slow boiling of magma chambers and the dynamics of explosive eruptionsJour. Vol. Geotherm. Res., Vol. 110, No. 1-2, Sept. pp. 121-36.GlobalMagma, Phreatomagmatic
DS2000-0053
2000
Giacomo, S.M.Baker, C.K., Giacomo, S.M.Resources and reserves: their uses and abuses by the equity marketsMin. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 667-76.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS200412-1228
2004
Giadini, D.Marone, F., Van der Meijde, M., Van der Lee, S., Giadini, D.Joint inversion of local, regional and teleseismic dat a for crustal thickness in the Eurasia Africa plate boundary region.Geophysical Journal International, Vol. 154, 2, pp. 499-514.Europe, AsiaGeophysics - seismics, boundary
DS2002-0565
2002
Giambiagi, L.B.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
DS1997-0394
1997
Giampaolo, C.Giampaolo, C., Godano, R.F., Barrese, E.The alteration of leucite bearing rocks: a possible mechanismEuropean Journal of Mineralogy, Vol. 9, No. 6, Nov. 1, pp. 1277-1292.ItalyLeucite
DS1985-0521
1985
Giampiero, P.Peccerillo, A., Giampiero, P.Primary Potassic Magmas in the Roman Province: Condition Of genesis and Geodynamic Implications.Geological Association of Canada (GAC)., Vol. 10, P. A47, (abstract.).ItalyBlank
DS201911-2526
2019
Giampouras, M.Giampouras, M., Garrido, C.J., Zwicker, J., Vadillo, I., Smrzka, D., Bach, W., Peckmann, J., Jemenez, P., Benavente, J., Garcia-Ruiz, J.M.Geochemistry and mineralogy of serpentinization driven hyperalkaline springs in the Ronda peridotite.Lithos, doi 10.1016/j.lithos.2019.105215, 75p. PdfEurope, Spaindeposit - Ronda

Abstract: We present a detailed study of the water geochemistry, mineralogy and textures in serpentinization-related hyperalkaline springs in the Ronda peridotites. Ronda waters can be classified into hyperalkaline fluids and river waters that are broadly similar to Ca2+-OH- and Mg2+-HCO3- water types described in serpentinite-hosted alkaline springs elsewhere. At the discharge sites of the fluids (fractures or human made outlets) and ponds along the fluid flow paths, the fluids are hyperalkaline (10.9 < pH < 12) and characterized by low Mg and high Na, K, Ca, and Cl concentrations. River waters, occurring near the spring sites, are mildly alkaline (8.5 < pH < 8.9) and enriched in Mg and DIC compared to Na, K, Ca and Cl. The chemistry of Ronda Mg-HCO3 river waters is likely due to the hydrolysis of ferromagnesian peridotite minerals in equilibrium with the atmosphere by infiltrated meteoric water and shallow groundwater in the serpentinized peridotite. The Ronda Ca-OH hyperalkaline fluids are generated by the combination of low temperature serpentinization reactions from infiltrated surface Mg-HCO3 river waters —or Ca-HCO3 waters from near karst aquifers— and deep carbonate precipitation isolated from atmospheric CO2. Mass balance calculations indicate that the weathering of Ca-bearing peridotite silicates such as diopside is a feasible source of Ca in Ronda Ca-OH hyperalkaline fluids; however, it requires steady-state dissolution rates substantially greater than those determined experimentally. Travertine, crystalline crusts and sediment deposits are the main types of solid precipitates observed in Ronda hyperalkaline spring sites. Calcite and aragonite, minor dolomite and Mg-Al-rich clays are the main minerals in the spring sites. As illustrated in the Baños del Puerto spring site, (i) calcite-dominated precipitation is due to hyperalkaline fluid uptake of atmospheric CO2 during discharge, and (ii) aragonite-dominated precipitation is due to mixing of Ca-OH hyperalkaline fluids with Mg- HCO3 river waters. Aragonite and dolomite contents increase away from the springs and toward the river waters that uniquely reflects the effect of Mg ions on the precipitation of aragonite versus calcite. Other potential factors controlling the precipitation of these CaCO3 polymorphs are the Mg/Ca ratio, the CO2 content, and the temperature of the fluids. Dolomite forms during lithification of travertine due to periodic flooding of river water combined with subsequent evaporation.
DS201904-0714
2019
Gianese, A.Anzolini, C., Nestola, F., Mazzucchelli, M.L., Alvaro, M., Nimis, P., Gianese, A., Morganti, S., Marone, F., Campione, M., Hutchison, M.T., Harris, J.W.Depth of diamond formation obtained from single periclase inclusions. SDD ( Super Deep Diamonds)Geology , Vol. 47, 3, pp. 219-222.South America, Brazil, Guyanadiamond genesis

Abstract: Super-deep diamonds (SDDs) are those that form at depths between ?300 and ?1000 km in Earth’s mantle. They compose only 1% of the entire diamond population but play a pivotal role in geology, as they represent the deepest direct samples from the interior of our planet. Ferropericlase, (Mg,Fe)O, is the most abundant mineral found as inclusions in SDDs and, when associated with low-Ni enstatite, which is interpreted as retrogressed bridgmanite, is considered proof of a lower-mantle origin. As this mineral association in diamond is very rare, the depth of formation of most ferropericlase inclusions remains uncertain. Here we report geobarometric estimates based on both elasticity and elastoplasticity theories for two ferropericlase inclusions, not associated with enstatite, from a single Brazilian diamond. We obtained a minimum depth of entrapment of 15.7 (±2.5) GPa at 1830 (±45) K (?450 [±70] km depth), placing the origin of the diamond-inclusion pairs at least near the upper mantle-transition zone boundary and confirming their super-deep origin. Our analytical approach can be applied to any type of mineral inclusion in diamond and is expected to allow better insights into the depth distribution and origin of SDDs.
DS201610-1893
2016
Gianni, M.Pamato, M.G., Kurnosov, A., Boffa Ballaran, T., Frost, D.J., Ziberna, L., Gianni, M., Speziale, S., Tkachev, S.N., Zhuravlev, K.K., Prakapenka, V.B.Single crystal elasticity of majoritic garnets: stagnant slabs and thermal anomalies at the base of the transition zone.Earth and Planetary Science Letters, Vol. 451, pp. 114-124.MantleSubduction

Abstract: The elastic properties of two single crystals of majoritic garnet (Mg3.24Al1.53Si3.23O12 and Mg3.01Fe0.17Al1.68Si3.15O12), have been measured using simultaneously single-crystal X-ray diffraction and Brillouin spectroscopy in an externally heated diamond anvil cell with Ne as pressure transmitting medium at conditions up to ?30 GPa and ?600 K. This combination of techniques makes it possible to use the bulk modulus and unit-cell volume at each condition to calculate the absolute pressure, independently of secondary pressure calibrants. Substitution of the majorite component into pyrope garnet lowers both the bulk (KsKs) and shear modulus (G ). The substitution of Fe was found to cause a small but resolvable increase in KsKs that was accompanied by a decrease in ?Ks/?P?Ks/?P, the first pressure derivative of the bulk modulus. Fe substitution had no influence on either the shear modulus or its pressure derivative. The obtained elasticity data were used to derive a thermo-elastic model to describe VsVs and VpVp of complex garnet solid solutions. Using further elasticity data from the literature and thermodynamic models for mantle phase relations, velocities for mafic, harzburgitic and lherzolitic bulk compositions at the base of Earth's transition zone were calculated. The results show that VsVs predicted by seismic reference models are faster than those calculated for all three types of lithologies along a typical mantle adiabat within the bottom 150 km of the transition zone. The anomalously fast seismic shear velocities might be explained if laterally extensive sections of subducted harzburgite-rich slabs pile up at the base of the transition zone and lower average mantle temperatures within this depth range.
DS2001-0465
2001
Giannuzzi, L.Heaney, P.J., Vicenzi, E.P., Giannuzzi, L., Livi, K.J.T.Focused ion beam milling: a method of site specific sample extraction for microanalysis of Earth materials.American Mineralogist, Vol. 86, pp. 1094-99.GlobalMicroanalysis - TEM, FIB
DS201904-0738
2019
Gianola, O.Galli, A., Grassi, D., Sartori, G., Gianola, O., Burg, J-P., Schmidt, M.W.Jurassic carbonatite and alkaline magmatism in the Ivrea zone ( European Alps) related to the breakup of Pangea.Geology, Vol. 47, 3, pp. 199-202..Europecarbonatite

Abstract: We report on pipe-like bodies and dikes of carbonate rocks related to sodic alkaline intrusions and amphibole mantle peridotites in the Ivrea zone (European Southern Alps). The carbonate rocks have bulk trace-element concentrations typical of low-rare earth element carbonatites interpreted as cumulates of carbonatite melts. Faintly zoned zircons from these carbonate rocks contain calcite inclusions and have trace-element compositions akin to those of carbonatite zircons. Laser ablation-inductively coupled plasma-mass spectrometry U-Pb zircon dating yields concordant ages of 187 ± 2.4 and 192 ± 2.5 Ma, coeval with sodic alkaline magmatism in the Ivrea zone. Cross-cutting relations, ages, as well as bulk and zircon geochemistry indicate that the carbonate rocks are carbonatites, the first ones reported from the Alps. Carbonatites and alkaline intrusions are comagmatic and were emplaced in the nascent passive margin of Adria during the Early Jurassic breakup of Pangea. Extension caused partial melting of amphibole-rich mantle domains, yielding sodic alkaline magmas whose fractionation led to carbonatite-silicate melt immiscibility. Similar occurrences in other rifts suggest that small-scale, sodic and CO2-rich alkaline magmatism is a typical result of extension and decompression-driven reactivation of amphibole-bearing lithospheric mantle during passive continental breakup and the evolution of magma-poor rifts.
DS1950-0148
1953
Giardini, A.A.Mitchell, R.S., Giardini, A.A.Oriented Olivine Inclusions in DiamondAmerican Mineralogist., Vol. 38, No. 1-2, PP. 136-138.GlobalDiamond Morphology
DS1970-0915
1974
Giardini, A.A.Giardini, A.A., Hurst, V.J., Melton, C.E., Stormer, J.C.Jr.Biotite As a Primary Inclusion in Diamond: its Nature and Significance.American Mineralogist., Vol. 59, PP. 783-789.United States, Gulf Coast, Arkansas, Pennsylvania, South AfricaMineral Chemistry
DS1970-0959
1974
Giardini, A.A.Melton, C.E., Giardini, A.A.The Composition and Significance of Gas Released from Natural Diamonds from Africa and Brasil.American MINERALOGIST., Vol. 59, No. 7-8, PP. 775-782.South Africa, BrazilMineralogy, Diamond Genesis
DS1975-0081
1975
Giardini, A.A.Giardini, A.A., Melton, C.E.Chemical Dat a on a Colorless Arkansaw Diamond and its Black amorphous C Iron Nickel S Inclusion.American Mineralogist., Vol. 60, PP. 934-936.United States, Gulf Coast, Arkansas, PennsylvaniaMineral Chemistry, Age Of Diamonds
DS1975-0082
1975
Giardini, A.A.Giardini, A.A., Melton, C.E.The Nature of Cloud Like Inclusions in Two Arkansaw DiamondsAmerican Mineralogist., Vol. 60, PP. 932-933.United States, Gulf Coast, Arkansas, PennsylvaniaMineralogy
DS1975-0135
1975
Giardini, A.A.Melton, C.E., Giardini, A.A.Experimental Results and a Theoretical Interpretation of Gaseous Inclusions Found in Arkansaw Natural Diamonds.American Mineralogist., Vol. 60, PP. 413-417.United States, Gulf Coast, Arkansas, PennsylvaniaMineral Chemistry
DS1975-0577
1977
Giardini, A.A.Mitchell, R.S., Giardini, A.A.Some Mineral Inclusions from African and Brazilian Diamonds: Their Nature and Significance.American MINERALOGIST., Vol. 62, No. 7-8, PP. 756-762.South Africa, BrazilMineral Chemistry
DS1975-0588
1977
Giardini, A.A.Newton, M.G., Melton, C.E., Giardini, A.A.Mineral Inclusion in an Arkansaw DiamondAmerican Mineralogist., Vol. 62, No. 5-6, PP. 583-586.United States, Gulf Coast, Arkansas, PennsylvaniaMineralogy, Murfreesboro
DS1975-0750
1978
Giardini, A.A.Gogineni, S.V., Melton, C.E., Giardini, A.A.Some Petrological Aspects of the Prairie Creek Diamond Bearing Kimberlite Diatreme, Arkansaw.Contributions to Mineralogy and Petrology, Vol. 66, No. 3, PP. 251-262.United States, Gulf Coast, Arkansas, PennsylvaniaPetrology, Lamproite
DS1980-0233
1980
Giardini, A.A.Melton, C.E., Giardini, A.A.The Isotopic Composition of Argon Included in an Arkansaw Diamond and its Significance.Geophysical Research. LETTERS, Vol. 7, No. 6, PP. 461-464.United States, Gulf Coast, Arkansas, PennsylvaniaIsotope, Inclusion, Mineral Chemistry
DS1981-0298
1981
Giardini, A.A.Melton, C.E., Giardini, A.A.The Nature and Significance of Occluded Fluids in Three Indian Diamonds.American Mineralogist., Vol. 66, No. 7-8, JULY-AUGUST PP. 746-750.India, PannaMineral Chemistry
DS1982-0429
1982
Giardini, A.A.Melton, C.E., Giardini, A.A.The Evolution of the Earth's Atmosphere and OceansGeophysical Research Letters, Vol. 9, No. 5, May pp. 579-82.ArkansasDiamonds
DS1987-0464
1987
Giardini, A.A.Melton, C.E., Giardini, A.A.A model to explain the earth's magnetic field and othergeodynamicphenomenaJournal of Petroleum Geology, Vol. 10, No. 4, October pp. 441-452GlobalGeophysics
DS1999-0053
1999
Giardini, D.Becker, T.W., Faccena, C., Giardini, D.The development of slabs in the upper mantle: insights from numerical and laboratory experiments.Journal of Geophysical Research, Vol. 104, No. 7, July 10, pp. 15207-26.MantleExperimental, Subduction
DS2003-0198
2003
Giardini, D.Cammarano, F., Goes, S., Vacher, P., Giardini, D.Inferring upper mantle temperatures from seismic velocitiesPhysics of the Earth and Planetary Interiors, Vol. 138, 3-4, pp. 197-222.MantleGeophysics - seismics
DS2003-1412
2003
Giardini, D.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantleScience, No. 5625, June 6, p. 1556-57.MantleWater
DS200412-0255
2003
Giardini, D.Cammarano, F., Goes, S., Vacher, P., Giardini, D.Inferring upper mantle temperatures from seismic velocities.Physics of the Earth and Planetary Interiors, Vol. 138, 3-4, pp. 197-222.MantleGeophysics - seismics
DS200412-0592
2004
Giardini, D.Funicello, F., Faccenna, C., Giardini, D.Role of lateral mantle flow in the evolution of subduction systems: insights from laboratory experiments.Geophysical Journal International, Vol. 157, 3, pp. 1393-1406.MantleSubduction
DS200412-1227
2004
Giardini, D.Marone, F., Van der Lee, S., Giardini, D.Three dimensional upper mantle S velocity model for the Eurasia Africa plate boundary region.Geophysical Journal International, Vol. 158, 1, pp.109-130.Africa, EuropeTectonics, geophysics - seismics
DS200412-2039
2003
Giardini, D.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantle.Science, No. 5625, June 6, p. 1556-57.MantleWater
DS200512-0131
2005
Giardini, D.Cammarano, F., Deuss, A., Goes, S., Giardini, D.One dimensional physical reference models for the upper mantle and transition zone: combining seismic and mineral physics constraints.Journal of Geophysical Research, Vol. 110, B1, B01306MantleGeophysics - seismics
DS200512-0132
2005
Giardini, D.Cammarano, F., Goes, S., Deuss, A., Giardini, D.Is a pyrolitic adiabatic mantle compatible with seismic data?Earth and Planetary Science Letters, Vol. 232, 3-4, April 15, pp. 227-243.MantleGeophysics - seismics
DS200712-0143
2007
Giardini, D.Capitanio, F.A., Goes, S., Morra, G., Giardini, D.Signatures of downgoing plate buoyancy driven subduction in motions and seismic coupling at major subduction zones.Earth and Planetary Science Letters, Vol. 262, 1-2, pp. 286-306.MantleSubduction
DS202005-0751
2020
Giardini, D.Munch, F.D., Khan, A., Tauzin, B., vn Driel, M., Giardini, D.Seismological evidence for thermo-chemical heterogeneity in Earth's continental mantle.Earth and Planetary Science Letters, Vol. 539, 116240 9p. PdfMantlegeophysics - seismics

Abstract: Earth's thermo-chemical structure exerts a fundamental control on mantle convection, plate tectonics, and surface volcanism. There are indications that mantle convection occurs as an intermittent-stage process between layered and whole mantle convection in interaction with a compositional stratification at 660 km depth. However, the presence and possible role of any compositional layering in the mantle remains to be ascertained and understood. By interfacing inversion of a novel global seismic data set with petrologic phase equilibrium calculations, we show that a compositional boundary is not required to explain short- and long-period seismic data sensitive to the upper mantle and transition zone beneath stable continental regions; yet, radial enrichment in basaltic material reproduces part of the complexity present in the data recorded near subduction zones and volcanically active regions. Our findings further indicate that: 1) cratonic regions are characterized by low mantle potential temperatures and significant lateral variability in mantle composition; and 2) chemical equilibration seems more difficult to achieve beneath stable cratonic regions. These findings suggest that the lithologic integrity of the subducted basalt and harzburgite may be better preserved for geologically significant times underneath cratonic regions.
DS1991-0568
1991
Giarmita, M.J.Giarmita, M.J., Sorenson, S.S.Fluids attending moderate depths of subduction: evidence from fluid inclusions in Type-C eclogites from high grade rocksGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 447GlobalEclogites, Subduction
DS1992-0559
1992
Giavocazzo, C.Giavocazzo, C.Fundamentals of crystallographyBlackwell Scientific, 500pGlobalCrystallography, Book -ad
DS1998-0712
1998
Gibb, A.J.Kamber, B.S., Frei, R., Gibb, A.J.pit falls and new approaches in granulite chronometry. an example from the Limpopo Belt, ZimbabwePrecambrian Research, Vol. 91, No. 3-4, Aug. 31, pp. 269-286ZimbabweGeochronology, Limpopo Belt
DS1996-0520
1996
Gibb, F.G.Gibb, F.G.Magmatic processes: do the answers lie in the rocks?Mineralogical Magazine, Vol. 60, No. 398, Feb. pp. 1-3.MantleTectonics - plate, Magmatism
DS1980-0085
1980
Gibb, F.G.F.Carswell, D.A., Gibb, F.G.F.Geothermometry of the Garnet Lherzolite Nodules with Special Reference to Those Kimberlites of Northern Lesotho.Contributions to Mineralogy and Petrology, Vol. 74, No. 4, PP. 403-416.LesothoGeothermometry
DS1980-0086
1980
Gibb, F.G.F.Carswell, D.A., Gibb, F.G.F.The Equilibrium Conditions and Petrogenesis of European Crustal Garnet Lherzolites.Lithos, Vol. 13, No. 1, PP. 19-30.ScandinaviaPetrography
DS1980-0141
1980
Gibb, F.G.F.Gibb, F.G.F.Geothermometry of Garnet Lherzolite Nodules with Special Reference to Those from the Kimberlites of Northern Lesotho.Contributions to Mineralogy and Petrology, Vol. 74, PP. 403-416.LesothoGeothermometry
DS1981-0112
1981
Gibb, F.G.F.Carswell, D.A., Dawson, J.B., Gibb, F.G.F.Equilibrium Conditions of Upper Mantle Eclogites: Implications for Kyanite Bearing and Diamondiferous Varieties.Mineralogical Magazine., Vol. 44, PP. 79-89.South AfricaRoberts Victor, Bellsbank, Petrology
DS1987-0089
1987
Gibb, F.G.F.Carswell, D.A., Gibb, F.G.F.Evaluation of mineral thermometers and barometers applicable to garnetlherzolite assemblagesContributions to Mineralogy and Petrology, Vol. 95, No. 4, pp. 499-511GlobalGeochemistry, Geobarometry
DS1987-0090
1987
Gibb, F.G.F.Carswell, D.A., Gibb, F.G.F.Garnet lherzolite xenoliths in the kimberlites of northernLesotho:revised P-T equilibraium conditions and upper mantlePaleogeotherM.Contributions to Mineralogy and Petrology, Vol. 97, No. 4, pp. 473-487LesothoKimberlite, Geothermometry
DS1996-0521
1996
Gibb, F.G.F.Gibb, F.G.F., Henderson, C.M.B.Magmatic processes - introductionMineralogical Magazine, Vol. 60, No. 1, Feb pp. 1-4GlobalMagmatic processes
DS1970-0295
1971
Gibb, R.A.Gibb, R.A., et al.A Precambrian Suture in the Canadian ShieldEarth and Planetary Science Letters, Vol. 10, pp. 417-22.Labrador, QuebecTectonics - Lineaments
DS1983-0249
1983
Gibb, R.A.Gibb, R.A.Model for Suturing of Superior and Churchill Plates: an Example of Double Indentation Tectonics.Geology, Vol. 11, No. 7, PP. 413-417.CanadaGeotectonics
DS1983-0250
1983
Gibb, R.A.Gibb, R.A., et al.Geophysics of Proposed Proterozoic Sutures in CanadaPrecambrian Research, Vol. 19, pp. 349-384.Canada, Shield, Northwest Territories, OntarioTectonics - Lineaments
DS1983-0251
1983
Gibb, R.A.Gibb, R.A., et al.Model for suturing of Superior and Churchill plates: an example of double indentation tectonics.Geology, Vol. 11, No. 7, July pp. 413-17.Ontario, Labrador, QuebecTectonics - Lineaments
DS1989-1217
1989
Gibb, R.A.Pilkington, M., Grieve, R.A.F., Gibb, R.A., Halpenny, J.F.Derived potential field dat a sets for North AmericaGeological Society of Canada (GSC) Forum 1989, P. 20 abstractGlobalMidcontinent, Geophysics
DS1991-1711
1991
Gibb, R.A.Teskey, D.J., Thomas, M.D., Gibb, R.A., Dods, S.D., Kucks, R.P.High resolution aeromagnetic survey of Lake SuperiorEos, Vol. 72, No. 8, February 19, p. 81, 85, 86Ontario, MichiganBlank
DS1993-1584
1993
Gibb, R.A.Teskey, D.J., Dumont, R., Stone, P.E., Gibb, R.A.The aeromagnetic survey program of the Geological Society of Canada (GSC)- implications for kimberliteexploration.Mid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 27-30.Northwest TerritoriesGeophysics
DS1994-0617
1994
Gibb, R.A.Gibb, R.A., Hinze, W.J., Thomas, M.D.Potential field studies of continental rifts -The Great Lakes region:introduction.Canadian Journal of Earth Sciences, Vol. 31, No. 4, April pp. 617-618.Ontario, MichiganGeophysics -seismics, Tectonics -Midcontinent rift
DS2000-0904
2000
Gibbard, P.L.Smith, G.R., Woodward, J.C., Gibbard, P.L.Interpreting Pleistocene glacial features from SPOT HRV dat a using fuzzy techniques.Computers and Geosciences, Vol. 26, No. 4, Apr. pp. 479-90.GlobalGeomorphology - not specific to diamonds, Remote sensing
DS1859-0098
1849
Gibbes, R.W.Gibbes, R.W.Report on the Geology of South Carolina South Quarterly Rev., Vol. 16, Oct. PP. 161-178.United States, North Carolina, South Carolina, Georgia, AppalachiaDiamond Occurrence
DS1860-0843
1894
Gibbins, H.J.Gibbins, H.J.Curiousities of DiamondThe Gentleman's Magazine., Vol. 52, PP. 243-250.Africa, South AfricaHistory
DS1992-0560
1992
Gibbins, W.A.Gibbins, W.A., Atkinson, D.Diamond exploration in the Northwest Territories #2northwest Territories Geology Division, Revised edition March 1992, 12 p. 7 figuresNorthwest TerritoriesDiamond exploration overview, Lac de Gras, Blackwater River, North Plateau, Somerset
DS1992-0561
1992
Gibbins, W.A.Gibbins, W.A., Atkinson, D.Diamond exploration in the Northwest Territories #1northwest Territories Geology Division, DIAND Yellowknife, 16pNorthwest TerritoriesOverview -history, Diamond exploration -current activities
DS1960-0346
1963
Gibbons, G.S.Gibbons, G.S., Pogson, D.J.Report on the Airly Mountain Diamond ProspectNew South Wales Geological Survey Report., GS 1963/001, (UNPUBL.).AustraliaKimberlite
DS1960-0347
1963
Gibbons, G.S.Gibbons, G.S., Pogson, D.J.Diamond Deposits at Mount Rose, Copeton, New South WalesNew South Wales Geological Survey Report., GS 1963/002, (UNPUBL.).AustraliaKimberlite
DS1960-0348
1963
Gibbons, G.S.Gibbons, G.S., Webster, S.S., Pogson, D.J.Investigations of Airly Mountains Diamond ProspectNew South Wales Geological Survey Report., GS 1963/064, (UNPUBL.).AustraliaKimberlite
DS1991-0165
1991
Gibbons, G.S.Branagan, D.F., Gibbons, G.S., Williams, K.L.The geological mapping of two southern continentsEdgeworth David Socity Department of Geology and Geophysics, University of, Australia, AntarcticaBook -ad, Geological mapping
DS201710-2218
2017
Gibbons, J.Burness, S., Smart, K.A., Stevens, G., Tappe, S., Sharp, Z.D., Gibbons, J.S-bearing metasomatism of mantle eclogites: constraints from the Kaapvaal craton and experiments.Goldschmidt Conference, 1p. AbstractAfrica, South Africadeposit - Roberts Victor, Jagersfontein
DS1989-0509
1989
Gibbs, A.Gibson, I.L., Roberts, R.G., Gibbs, A.An extensional fault model for the early development of greenstone belts- areplyEarth and Planetary Science Letters, Vol. 92, No. 1, February pp. 127-128OntarioGreenstone belt, Tectonics
DS1990-0215
1990
Gibbs, A.D.Blundell, D.J., Gibbs, A.D.Tectonic evolution of the North Sea riftsClarendon Press, Oxford, 272p. Cost?North SeaTectonics, Rifting
DS1983-0252
1983
Gibbs, A.K.Gibbs, A.K., Barron, C.N.The Guiana Shield ReviewedEpisodes, 1983, No. 2, PP. 7-14.South America, Guiana, Venezuela, Guyana, Suriname, French GuianaRegional Geology, Geotectonics, Stratigraphy, Roraima, Parguazan
DS1984-0303
1984
Gibbs, A.K.Gibbs, A.K., Payne, B., Setzer, T., Brown, L.D., Oliver, J.E.Seismic Reflection Study of the Precambrian Crust of Central Minnesota.Geological Society of America (GSA) Bulletin., Vol. 95, No. 3, PP. 280-294.GlobalMid-continent
DS1985-0231
1985
Gibbs, A.K.Gibbs, A.K.Contrasting Styles of Continental Mafic Intrusions in the Guiana Shield.International Symposium ON MAFIC DIKE SWARMS, HELD TORONTO, JUNE 4-7TH, 22P. 5 FIGS.South America, Guiana, Brazil, Venezuela, GuyanaLamprophyres, Carbonatite, Geotectonics
DS1985-0232
1985
Gibbs, A.K.Gibbs, A.K., Wirth, K.R.Origin and Evolution of the Amazonian CratonLunar Planetary Science Institute, Nasa Workshop On Early Cr, JUNE-JULY , 4P.South America, Guiana, French Guiana, BrazilGeotectonics, Granite, Greenstone Belts
DS1987-0250
1987
Gibbs, A.K.Gibbs, A.K.Contrasting styles of continental mafic intrusions in the Guiana Shieldin: Mafic dyke swarms, editors, Halls, H.C., Fahrig, W.F. Geological, Special Paper 34, pp. 457-465VenezuelaRoraima Group p. 461
DS1992-0562
1992
Gibbs, A.K.Gibbs, A.K., Barron, C.N.Geology of the Guyana shieldOxford University of Press, 304p. 1 color map approx.$ 85.00 United StatesGuyanaGeology, Regional
DS1992-0563
1992
Gibbs, A.K.Gibbs, A.K., Barron, C.N.Geology of the Kapuskasing-Groundhog-Missinaibi River area, Folyet andKapuskasingOxford University Press, 304pGuyana ShieldGeology Guyana shield, Book -ad
DS1993-0536
1993
Gibbs, A.K.Gibbs, A.K., Barron, C.N.Archean-Proterozoic supracrustals, Trans-Amazonian.The Geology of the Guiana Shield, Oxford University Press, approx. cost, 246pGlobalShield, Regional geology
DS1993-0537
1993
Gibbs, A.K.Gibbs, A.K., Barron, C.N.Mention of diamonds in index - SurimamThe Geology of the Guiana Shield, Oxford University Press, approx. cost, 246p. pp. 187, 192-195Guyana, Brazil, Roraima, Venezuela, French GuianaGeology, Guiana Shield
DS1993-0538
1993
Gibbs, A.K.Gibbs, A.K., Barron, C.N.The geology of the Guiana ShieldOxford University Press, 250pSouth AmericaGuiana shield, Book -table of contents
DS1993-0539
1993
Gibbs, A.K.Gibbs, A.K., Barron, C.N.Mention of diamonds in index - SurimamThe Geology of the Guiana Shield, Oxford University Press, approx. cost, 246p. pp. 189, 192SurinameGeology
DS1991-0569
1991
Gibbs, B.Gibbs, B., Krajewski, S.Directory of mining programs and public domain software for earthGibbs Associates, Directory $ 75.00 United States Software handbook $ 25.00 United StatesGlobalComputer, Program -directory
DS1991-0570
1991
Gibbs, B.Gibbs, B., Krajewski, S.Public domain software for earth scientists: handbook of public domain and inexpensive softwareGibbs and Associates, 189p. $ 40.00United StatesComputer programs, Lists
DS1991-0571
1991
Gibbs, B.Gibbs, B., Krajewski, S.A.Workshop attendees compare ore modeling and mine planning softwaresystemsMining Engineering, Vol. 43, No. 7, July pp. 732-737GlobalGeostatistics, Computer -programs for ore modeling comparisons
DS1992-0564
1992
Gibbs, B.L.Gibbs, B.L., Krajewski, S.A.Surface and underground mine modelling with computersMining Engineering, Vol. 44, No. 7, July pp. 689-693GlobalComputers, Program -Mine modelling
DS1994-0944
1994
Gibbs, B.L.Krajewski, S.A., Gibbs, B.L.Computers contouring generates artifactsGeotimes, Vol. 39, No. 4, April pp. 15-19GlobalComputer programs, Applications - artifacts
DS1996-0025
1996
Gibbs, B.L.Anderson, D.A., Gibbs, B.L.Mining the internet.Mining Engineering, Vol. 48, No. 2, Feb. pp. 48-52United StatesMining, Computers -internet
DS1997-0395
1997
Gibbs, B.L.Gibbs, B.L.Exploring with modern technology.... WEB for minerals informationEngineering and Mining Journal, Vol. 198, No. 12, Dec. pp. 32J-L.GlobalComputer - programs, WEB news
DS2003-0462
2003
Gibbs, B.L.Gibbs, B.L.Modeling makes the difference. Virtual designs result in more efficient productionEngineering and Mining Journal, April pp. 22-26.GlobalComputer - software - not specific to diamonds
DS200412-0659
2003
Gibbs, B.L.Gibbs, B.L.Modeling makes the difference. Virtual designs result in more efficient production.Engineering and Mining Journal, April pp. 22-26.TechnologyComputer - software - not specific to diamonds
DS2002-1370
2002
Gibbs, G.V.Ross, N.L., Gibbs, G.V., Rosso, K.M.Potential proton sites in high pressure silicates18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.80.MantleUHP mineralogy - perovskites
DS2003-0463
2003
Gibbs, G.V.Gibbs, G.V.The silica polymorph coesite: an exploration of the electron density distributionGeological Society of America, Annual Meeting Nov. 2-5, Abstracts p. 535.GlobalMineralogy - experimental
DS200412-0660
2003
Gibbs, G.V.Gibbs, G.V.The silica polymorph coesite: an exploration of the electron density distribution.Geological Society of America, Annual Meeting Nov. 2-5, Abstracts p. 535.TechnologyMineralogy - experimental
DS1997-0396
1997
Gibbs, W.W.Gibbs, W.W.Taking computers to taskScientific American, July pp. 82-89GlobalComputers - productivity
DS201912-2783
2019
Gibbs, W.W.Gibbs, W.W.A new form of pure carbon dazzles and attracts.Science, Vol. 366, 6467, pp. 782-783.Mantlecarbon

Abstract: A "happy accident" has yielded a new, stable form of pure carbon made from cheap feedstocks, researchers say. Like diamond and graphene, two other guises of carbon, the material seems to have extraordinary physical properties. It is harder than stainless steel, about as conductive, and as reflective as a polished aluminum mirror. Perhaps most surprising, the substance appears to be ferromagnetic, behaving like a permanent magnet at temperatures up to 125°C. The discovery, announced in a talk here at the International Symposium on Clusters and Nanomaterials, could lead to lightweight coatings, medical products, and novel electronic devices. The news has elicited both excitement and caution among the dozens of researchers attending the meeting. Experts note that carbon is much lighter than other ferromagnetic elements such as manganese, nickel, and iron. Moreover, carbon is nontoxic in the body—which could mean the substance could be used for making biosensors or drug-delivery carriers.
DS2003-0464
2003
Gibert, B.Gibert, B., Sepold, U., Tommasi, A., Mainprice, D.Thermal diffusivity of upper mantle rocks: influence of temperature, pressure and theJournal of Geophysical Research, Vol. 108, 8, ECV 1 , DOI 10.1029/2002JB002108MantleGeothermometry
DS200412-0661
2003
Gibert, B.Gibert, B., Sepold, U., Tommasi, A., Mainprice, D.Thermal diffusivity of upper mantle rocks: influence of temperature, pressure and the deformation fabric.Journal of Geophysical Research, Vol. 108, 8, ECV 1 , DOI 10.1029/2002 JB002108MantleGeothermometry
DS201212-0241
2012
Gibert, G.Gibert, G., Gerbault, M., Hassani, R., Tric, E.Dependency of slab geometry on absolute velocities and conditions for cyclicity: insights from numerical modelling.Geophysical Journal International, in press availableMantleSubduction
DS2000-0013
2000
Gibling, M.R.Alsop, G.I., Brown, J.P., Gibling, M.R.The geometry of drag zones adjacent to salt diapirsJournal of Geological Society of London, Vol. 157, No. 5, Sept.pp.1019-30.GlobalStructure - diapirs ( salt) not specific to diamond
DS201412-0289
2014
Gibney, E.Gibney, E.First buckball molecules created from boron.Nature, Vol. 511, July 17, pp. 330-333.TechnologyBrunswick anomaly
DS201112-0640
2011
GibsherMalkovets, V.G., Zedgenizov, Sobolev, Kuzmin, Gibsher, Shchukina, Golovin, Verichev, PokhilenkoContents of trace elements in olivines from diamonds and peridotite xenoliths of the V.Grib kimberlite pipe ( Arkhangel'sk Diamondiferous province, Russia).Doklady Earth Sciences, Vol. 436, 2, pp. 301-307.RussiaDeposit - Grib
DS201012-0234
2010
Gibsher, A.Gibsher, A., Malkovets, V., Travin, A.New Ar Ar dat a of the lamprophyric dykes of west Sangilen ( southeast Tuva south Russia): the oldest mantle xenoliths bearing basaltic hosts.International Dyke Conference Held Feb. 6, India, 1p. AbstractRussia, TuvaGeochronology
DS201903-0512
2018
Gibsher, A.Gibsher, A.Mineral inclusions in Siberian diamonds: mineralogy, geochemistry and application to diamond exploration.7th Symposio Brasleiro de geologia do diamante, 22 ppts. Pdf availableRussia, Siberiadiamond inclusions
DS201212-0242
2012
Gibsher, A.A.Gibsher, A.A., Malkovets, V.G., Griffin, W.L., O'Reilly, S.Y.Petrogenesis of composite xenoliths from alkaline basalts ( West Sangilen) Russia10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussiaAlkalic
DS201212-0583
2012
Gibsher, A.A.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
Gibsher, A.A.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
Gibsher, A.A.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
DS201612-2320
2016
Gibsher, A.A.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.
DS201801-0060
2018
Gibsher, A.A.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.
DS201808-1788
2018
Gibsher, A.A.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.
DS201911-2544
2019
Gibsher, A.A.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].
DS202010-1840
2020
Gibsher, A.A.Dymshits, A., Sharygin, I., Malkovets, V., Yakovlev, I.V., Gibsher, A.A., Alifirova, T.A., Vorobei, S.S., Potapov, S.V., Garanin, V.K.Thermal state, thickness and composition of the lithospheric mantle beneath the Upper Muna kimberlite field, Siberian Craton, constrained by clinopyroxene xenocrysts and comparison with Daldyn and Mirny fields.Minerals, 10.1039/DOJA00308E 20p. PdfRussiadeposit - Muna

Abstract: To gain better insight into the thermal state and composition of the lithospheric mantle beneath the Upper Muna kimberlite field (Siberian craton), a suite of 323 clinopyroxene xenocrysts and 10 mantle xenoliths from the Komsomolskaya-Magnitnaya (KM) pipe have been studied. We selected 188 clinopyroxene grains suitable for precise pressure (P)-temperature (T) estimation using single-clinopyroxene thermobarometry. The majority of P-T points lie along a narrow, elongated field in P-T space with a cluster of high-T and high-P points above 1300 °C, which deviates from the main P-T trend. The latter points may record a thermal event associated with kimberlite magmatism (a “stepped” or “kinked” geotherm). In order to eliminate these factors, the steady-state mantle paleogeotherm for the KM pipe at the time of initiation of kimberlite magmatism (Late Devonian-Early Carboniferous) was constrained by numerical fitting of P-T points below T = 1200 °C. The obtained mantle paleogeotherm is similar to the one from the nearby Novinka pipe, corresponding to a ~34-35 mW/m2 surface heat flux, 225-230 km lithospheric thickness, and 110-120 thick "diamond window" for the Upper Muna field. Coarse peridotite xenoliths are consistent in their P-T estimates with the steady-state mantle paleogeotherm derived from clinopyroxene xenocrysts, whereas porphyroclastic ones plot within the cluster of high-T and high-P clinopyroxene xenocrysts. Discrimination using Cr2O3 demonstrates that peridotitic clinopyroxene xenocrysts are prevalent (89%) among all studied 323 xenocrysts, suggesting that the Upper Muna mantle is predominantly composed of peridotites. Clinopyroxene-poor or -free peridotitic rocks such as harzburgites and dunites may be evident at depths of 140-180 km in the Upper Muna mantle. Judging solely from the thermal considerations and the thickness of the lithosphere, the KM and Novinka pipes should have excellent diamond potential. However, all pipes in the Upper Muna field have low diamond grades (<0.9, in carats/ton), although the lithosphere thickness is almost similar to the values obtained for the high-grade Udachnaya and Mir pipes from the Daldyn and Mirny fields, respectively. Therefore, other factors have affected the diamond grade of the Upper Muna kimberlite field.
DS202104-0591
2021
Gibsher, A.A.Malkovets, V.G., Shatsky, V.S., Dak, A.I., Gibsher, A.A., Yakovlev, I.V., Belousova, E.A., Tsujimori, T., Sobolev, N.V.Evidence for multistage and polychronous alkaline-ultrabasic Mesozoic magmatism in the area of diamondiferous placers of the Ebelyakh River basin, ( eastern slope of the Anabar shield).Doklady Earth Sciences, Vol. 496, 1, pp. 48-52.Russiadeposit - Anabar

Abstract: New mineralogical and isotope-geochemical data for zircon megacrysts (n = 48) from alluvium of Kholomolokh Creek (a tributary of the Ebelakh River) are reported. Using the geochemical classification schemes, the presence of zircons of kimberlitic and carbonatitic genesis was shown. The U-Pb dating of zircons revealed two major age populations: the Triassic (258-221 Ma, n = 18) and Jurassic (192-154 Ma, n = 30). Weighted mean 206Pb/238U ages allowed us to distinguish the following age stages: 155 ± 3, 161 ± 2, 177 ± 1.5, 183 ± 1.5, 190 ± 2, 233 ± 2.5, and 252 ± 4 Ma. It is suggested that the Ebelyakh diamonds could have been transported from the mantle depths by kimberlite, as well as by other related rocks, such as carbonatite, lamprophyre, lamproite, olivine melilitite, etc. Diamonds from the Ebelyakh placers most likely have polygenic native sources and may be associated with polychronous and multistage Middle Paleozoic and Mesozoic kimberlite and alkaline-ultrabasic magmatism in the eastern slope of the Anabar Shield (the Ebelyakh, Mayat, and Billyakh river basins).
DS2000-0133
2000
GibsonByron, M.J., Gibson, Watkinson, Whitehead, McDonaldExtraordinary accessory minerals of the Mat a Da Corda Formation: implications for rock type classificationGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Calgary May 2000, 5p.BrazilPetrology, mineralogy, exploration, diamond, igneous, Mata Da Corda Formation
DS2001-0134
2001
GibsonBrod, J., Gaspar, De Araujo, Gibson, Thompson, JunqueiraPhlogopite and tetra ferriphlogopite from Brazilian carbonatite complexes and implications for systematicsJournal of African Earth Sciences, Vol. 19, No. 3, Apr. pp.265-296.BrazilCarbonatite, Mineral chemistry systematics
DS2002-1591
2002
GibsonThompson, R.N., Smith, P.M., Gibson, Mattey, DickinAnkerite carbonatite from Swartbooisdrif Namibia: the first evidence for magmatic ferrocarbonatite.Contribution to Mineralogy and Petrology, Vol.143,3,June,pp. 377-96., Vol.143,3,June,pp. 377-96.NamibiaCarbonatite
DS2002-1592
2002
GibsonThompson, R.N., Smith, P.M., Gibson, Mattey, DickinAnkerite carbonatite from Swartbooisdrif Namibia: the first evidence for magmatic ferrocarbonatite.Contribution to Mineralogy and Petrology, Vol.143,3,June,pp. 377-96., Vol.143,3,June,pp. 377-96.NamibiaCarbonatite
DS201112-0409
2011
Gibson, B.Hannam, S., Bailey, B.L., Lindsay, M.B.J., Gibson, B., Blowes, D.W., Paktunc, A.D., Smith, L., Sego, D.C.Diavik waste rock project: geochemical and mineralogical characterization of waste rock weathering at the Diavik diamond mine.Yellowknife Geoscience Forum Abstracts for 2011, abstract p. 43-44.Canada, Northwest TerritoriesMining - waste rock
DS202003-0367
2020
Gibson, C.Turetsky, M.R., Abbott, B.W., Jones, M.C., Walter Anthony, K.. Olefeldt, D., Schuur, E.A.G., Grosse, G., Kuhry, P., Higelius, G., Koven, C., Lawrence, D.M., Gibson, C., Sannel, A.B.K., McGuire, A.D.Carbon release through abrupt permafrost thaw. ( not specific to diamonds but interest)Nature Geoscience, Vol. 13, pp. 138-143.Mantlecarbon

Abstract: The permafrost zone is expected to be a substantial carbon source to the atmosphere, yet large-scale models currently only simulate gradual changes in seasonally thawed soil. Abrupt thaw will probably occur in <20% of the permafrost zone but could affect half of permafrost carbon through collapsing ground, rapid erosion and landslides. Here, we synthesize the best available information and develop inventory models to simulate abrupt thaw impacts on permafrost carbon balance. Emissions across 2.5?million?km2 of abrupt thaw could provide a similar climate feedback as gradual thaw emissions from the entire 18?million?km2 permafrost region under the warming projection of Representative Concentration Pathway 8.5. While models forecast that gradual thaw may lead to net ecosystem carbon uptake under projections of Representative Concentration Pathway 4.5, abrupt thaw emissions are likely to offset this potential carbon sink. Active hillslope erosional features will occupy 3% of abrupt thaw terrain by 2300 but emit one-third of abrupt thaw carbon losses. Thaw lakes and wetlands are methane hot spots but their carbon release is partially offset by slowly regrowing vegetation. After considering abrupt thaw stabilization, lake drainage and soil carbon uptake by vegetation regrowth, we conclude that models considering only gradual permafrost thaw are substantially underestimating carbon emissions from thawing permafrost.
DS1990-0566
1990
Gibson, D.W.Gibson, D.W., Edwards, D.E.An overview of Triassic stratigraphy and depositional environments in the Rocky Mountain foothills and western interior plains, Peace River Arch regionGeology of the Peace River Arch, ed. Sc.C. O'Connell, J.S. Bell, Bulletin. Can., Vol. 38A, Special Volume, December pp. 146-158AlbertaPeace River area, Tectonics, structure
DS1984-0018
1984
Gibson, E.K.Andrawes, F., Holzer, G., Roedder, E., Gibson, E.K., Oro, J.Gas Chromatographic Analysis of Volatiles in Fluid and Gas Inclusions.Journal of Chromatography, Vol. 302, PP. 181-193.GlobalFluid Inclusions, Diamonds, Geochemistry
DS201312-0968
2013
Gibson, G.M.White, L.T., Gibson, G.M., Lister, G.S.A reassessment of paleogeographic reconstructions of eastern Gondwana: bringing geology back into the equation.Gondwana Research, Vol. 24, 3-4, pp. 984-998.IndiaTectonic models
DS202103-0396
2021
Gibson, H.D.Neil, B.J.C., Gibson, H.D., Pehrsson, S.J., Martel, E., Thiessen, E.J., Crowley, J.L.Provenance, stratigraphic and precise depositional age constraints for an outlier of the 1.9 to 1.8 Ga Nonacho Group, Rae craton, Northwest Territories, Canada.Precambrian Research, Vol. 352, 105999, 15p. PdfCanada, Northwest Territoriesgeochronology

Abstract: The Nonacho Group comprises six formations of continental clastic rocks that were deposited between 1.91 and 1.83?Ga. The Nonacho Group is part of a broader assemblage of conglomerate and sandstone that was deposited atop the Rae craton in response to the amalgamation of Laurentia and supercontinent Nuna, but the details of its tectonic setting are contentious. This paper documents an outlier of Nonacho Group rocks ?50?km east of the main Nonacho basin. Field observations and LA-ICPMS (laser ablation inductively coupled plasma mass spectrometry) U-Pb detrital zircon geochronology are integrated with previous studies of the main basin to better understand the group’s depositional history, provenance and tectonic setting. The lithology and detrital zircon age spectra of the outlier allow for its correlation to the upper two formations of the Nonacho Group. CA-ID-TIMS (chemical abrasion isotope dilution thermal ionization mass spectrometry) analyses of two fragments of the youngest detrital zircon provide a maximum depositional age of 1901.0?±?0.9?Ma. A felsic volcanic cobble dated at ca. 2.38?Ga provides evidence of volcanism during the Arrowsmith orogeny. Detrital zircon dates recovered from the outlier (ca. 3.4-3.0, 2.7, 2.5-2.3 and 2.0-1.9?Ga) are consistent with derivation from topography of the Taltson and/or Thelon orogens on the western margin of the Rae craton. Taltson-Thelon (2.0 to 1.9?Ga) aged detritus is only abundant in the upper two formations of the Nonacho Group, marking a change in provenance from the lower formations. This change in provenance may have coincided with a period of renewed uplift and the unroofing of Taltson-Thelon plutons. The detrital zircon provenance and depositional age of the Nonacho Group is consistent with models that link its deposition to the Taltson and/or Thelon orogens. However, tectonism associated with the 1.9 to 1.8?Ga Snowbird and Trans-Hudson orogens to the east could also have affected basin formation or the change in provenance from the lower to upper Nonacho Group. This study highlights the importance of CA-ID-TIMS in establishing accurate and precise maximum depositional ages for sedimentary successions.
DS2000-0132
2000
Gibson, H.L.Byron, M.J., Gibson, H.L., Whitehead, Watkinson, WinterThe Quintinos pipe: a polyphase kamafugite intrusion of the Mat a da Corda Formation, Minas Gerais, Brasil.Geological Association of Canada (GAC)/Mineralogical Association of, 4p. abstractBrazil, Minas GeraisLamproite, Deposit - Quintinois
DS1975-0157
1975
Gibson, I.L.Paul, D.K., Potts, P.J., Gibson, I.L., Harris, P.G.Rare Earth Abundances in Indian KimberlitesEarth and Planetary Science Letters, Vol. 25, PP. 151-158.IndiaRare Earth Elements (ree), Geochemistry
DS1981-0317
1981
Gibson, I.L.Nixon, P.H., Rogers, N.W., Gibson, I.L., Grey, A.Depleted and Fertile Mantle Xenoliths from Southern Africankimberlites.Annual Review of Earth and Planetary Science, Vol. 9, PP. 285-309.South AfricaKimberlite Genesis
DS1989-0509
1989
Gibson, I.L.Gibson, I.L., Roberts, R.G., Gibbs, A.An extensional fault model for the early development of greenstone belts- areplyEarth and Planetary Science Letters, Vol. 92, No. 1, February pp. 127-128OntarioGreenstone belt, Tectonics
DS1995-0537
1995
Gibson, J.G.Field, M., Gibson, J.G., Wilkes, T.A., Gababotse, KhujweThe geology of the Orapa A/K1 kimberlite, Botswana: further insight into the emplacement of kimb. pipes.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 155-57.BotswanaKimberlite genesis, Deposit -Orapa A/K1
DS1988-0278
1988
Gibson, R.Guptill, S.C., Cotter, D., Gibson, R., Liston, R., Tom, H., Trainor, T.A process for evaluating geographic information systemsUnited States Geological Survey (USGS) Open File, No. 88-0105, 55p. $ 21.25GlobalGIS, Technology Group
DS1995-0629
1995
Gibson, R.L.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
DS1996-1372
1996
Gibson, R.L.Stevens, G., Gibson, R.L., Droop, G.T.R.Polyphase granulite metamorphism in the Vredefort Dome: a window into the deep Kaapvaal craton at 2.06 GaEconomic Geology Research Unit, No. 297, 27pSouth AfricaCraton -Kaapvaal, Greenstone remnants
DS1997-0397
1997
Gibson, R.L.Gibson, R.L., Stevens, G.Regional metamorphism due to anorogenic intracratonic magmatismEconomic Geology Research Unit, No. 311, 23pSouth AfricaVerdefort Dome, impact structure, Kaapvaal Craton, Mantle derived magmas
DS1997-0398
1997
Gibson, R.L.Gibson, R.L., Stevens, G.Regional metamorphism due to anorogenic intracratonic magmatismEconomic Geology Research Unit, No. 311, 23p.South AfricaKaapvaal Craton, Mantle
DS1997-1104
1997
Gibson, R.L.Stevens, G., Gibson, R.L., Droop, G.T.R.Mid-crustal granulite facies metamorphism in the Central Kaapvaal Craton:Bushveld Complex connectionPrecambrian Research, Vol. 82, No. 1-2, March 1, pp. 113-32South AfricaCraton - Kaapvall, Bushveld Complex, layered intrusion
DS1997-1105
1997
Gibson, R.L.Stevens, G., Gibson, R.L., Droop, G.T.R.Mid crustal granulite facies metamorphism in the Central Kaapvaal craton:Bushveld Complex connectionPrecambrian Research, Vol. 82, No. 1-2, March pp. 113-132South Africametamorphism, Bushveld Complex
DS1998-0181
1998
Gibson, R.L.Buick, I.S., Uken, R., Gibson, R.L., Wallmach, T.High delta 13 C Paleoproterozoic carbonates from the Transvaal South AfricaGeology, Vol. 26, No. 10, Oct. pp. 875-8South AfricaKaapvaal Craton, Geochronology, Carbon
DS1998-0505
1998
Gibson, R.L.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
DS1998-0758
1998
Gibson, R.L.Kisters, A.F.M., Gibson, R.L., Anhaeusser, C.R.The role of strain localization in the segregation and ascent of anatecticmelts, Namaqualand, South AfricaJournal of Struct. Geol, Vol. 20, No. 2-3, Feb.1, pp. 229-42South AfricaTectonics
DS2002-0566
2002
Gibson, R.L.Gibson, R.L., Jones, MQW.Late Archean to Paleoproterozoic geotherms in the Kaapvaal Craton, South Africa: constraints on the thermal evolution of the Witwatersrand Basin.Basin Research, Vol.14,2, pp.169-82.South AfricaTectonics, Georthermometry
DS2003-0181
2003
Gibson, R.L.Buick, I.S., Williams, I.S., Gibson, R.L., Cartwright, I., Miller, J.A.Carbon and U Pb evidence for a Paleoproterozoic crustal component in the CentralJournal of the Geological Society of London, Vol. 160, 4, pp. 601-12.South AfricaGeochronology, Mobile belt - not specific to diamonds
DS2003-0771
2003
Gibson, R.L.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
DS200412-0238
2003
Gibson, R.L.Buick, I.S., Williams, I.S., Gibson, R.L., Cartwright, I., Miller, J.A.Carbon and U Pb evidence for a Paleoproterozoic crustal component in the Central Zone of the Limpopo Belt, South Africa.Journal of the Geological Society, Vol. 160, 4, pp. 601-12.Africa, South AfricaGeochronology Mobile belt - not specific to diamonds
DS200412-1082
2004
Gibson, R.L.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
DS200612-0037
2006
Gibson, R.L.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
Gibson, R.L.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
DS1996-0835
1996
Gibson, S.Leonardos, O.H., Thompson, R.N., Fleicher, R., Gibson, S.The origin of diamonds in western Minas Gerais, Brasil. Comment andreply., ,by Gonzaga, Teixeira and Gaspar.Mineral Deposits, Vol. 31, No. 4, May pp. 343-347.BrazilDiamond genesis
DS200512-1104
2005
Gibson, S.Tuff, J., Takahashi, E., Gibson, S.Experimental constraints on the role of garnet pyroxenite in the genesis of high Fe mantle plume derived melts.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantleMantle plume, ferro-picrites
DS201702-0218
2016
Gibson, S.Jennings, E.S., Holland, T.J.B., Shorttle, O., Gibson, S.The composition of melts from a heterogeneous mantle and origin of ferropicrite: application of a thermodynamic model.Journal of Petrology, In press available 22p.MantleEclogite, melting

Abstract: Evidence for chemical and lithological heterogeneity in the Earth’s convecting mantle is widely acknowledged, yet the major element signature imparted on mantle melts by this heterogeneity is still poorly resolved. In this study, a recent thermodynamic melting model is tested on a range of compositions that correspond to potential mantle lithologies (harzburgitic to pyroxenitic), to demonstrate its applicability over this compositional range, in particular for pyroxenite melting. Our results show that, despite the model’s calibration in peridotitic systems, it effectively reproduces experimental partial melt compositions for both Si-deficient and Si-excess pyroxenites. Importantly, the model accurately predicts the presence of a free silica phase at high pressures in Si-excess pyroxenites, indicating the activation of the pyroxene-garnet thermal divide. This thermal divide has a dominant control on solidus temperature, melt productivity and partial melt composition. The model is used to make new inferences on the link between mantle composition and melting behaviour. In silica-deficient and low-pressure (olivine-bearing) lithologies, melt composition is not very sensitive to source composition. Linearly varying the source composition between peridotite and basaltic pyroxenite, we find that the concentration of oxides in the melt tends to be buffered by the increased stability of more fusible phases, causing partial melts of even highly fertile lithologies to be similar to those of peridotite. An exception to this behaviour is FeO, which is elevated in partial melts of silica-deficient pyroxenite even if the bulk composition does not have a high FeO content relative to peridotite. Melt Al2O3 and MgO vary predominantly as a function of melting depth rather than bulk composition. We have applied the thermodynamic model to test the hypothesis that Fe-rich mantle melts such as ferropicrites are derived by partial melting of Si-deficient pyroxenite at elevated mantle potential temperatures. We show that the conspicuously high FeO in ferropicrites at a given MgO content does not require a high-Fe mantle source and is indeed best matched by model results involving around 0-20% melting of silica-deficient pyroxenite. A pyroxenite source lithology also accounts for the low CaO content of ferropicrites, whereas their characteristic low Al2O3 is a function of their high pressure of formation. Phanerozoic ferropicrites are exclusively located in continental flood basalt (CFB) provinces and this model of formation confirms that lithological heterogeneity (perhaps recycled oceanic crust) is present in CFB mantle sources.
DS201709-2002
2017
Gibson, S.Jackson, C., Gibson, S.New insights into sulfur-rich mantle metasomatism at Bultfontein, Kimberley.Goldschmidt Conference, abstract 1p.Africa, South Africadeposit - Bultfontein

Abstract: Metasomatised regions of Earth’s sub-continental lithospheric mantle potentially represent a large volatile reservoir. Nevertheless, the mechanisms involved in the storage and upward transport of volatiles such as C and S, from the convecting mantle and/or subducting slabs, are poorly understood. We have carried out a systematic microanalytical study of a suite of sulfide-rich mantle peridotites from the Bultfontein diamond mine, Kimberley. EDS mapping of large (>2mm), interstitial base metal sulfides in the Bultfontein xenoliths has identified distinct Ni-rich regions (pentlandite). The Ni-rich sulfides are adjacent to olivine with Ni poor rims (<0.2 wt% NiO). Diffusion profiles between the protolith olivines and adjacent sulfides are used to estimate the timing of the S-rich metasomatic event. The presence of large unequilibrated olivine indicates that Nisulfides were introduced immediately prior to kimberlite emplacement. The calculated composition of melt in equilibrium with metasomatic clinopyroxenes in the Bultfontein sulphide-bearing peridotites shows a strong correlation to high-density carbonatitic fluids trapped in diamonds. This association is extended by the wealth of metasomatic sulfides in the Bultfontein xenoliths. Moreover, Ni-rich sulfides (~25 wt%) are the most common mineral inclusion in peridotitic diamonds, implying that diamonds crystallise from a S-saturated fluid. Many studies attribute the metasomatism at Bultfontein to silicate melts associated with the kimberlite, but we explore the possibility of metasomatism by reactive percolation of a volatile-rich agent with carbonatitic affinity. The S-rich nature of the metasomatism and the correlation with diamond high-density fluids has great implications for the transport of volatiles from the deep mantle to shallow regions of the craton.
DS1991-0572
1991
Gibson, S.A.Gibson, S.A., Thompson, R.N., Leat, P.T., Morrison, M.A., HendryUltrapotassic magmas along the flanks of the oligo-miocene Rio Grande @Proceedings of Fifth International Kimberlite Conference held Araxa June, pp. 133-135Colorado PlateauTectonics, Kimberlites, minettes
DS1991-0573
1991
Gibson, S.A.Gibson, S.A., Thompson, R.N., Mitchell, J.G., Dickin, A.P.Geochemical and petrographic evidence for high magnesium-ultrapotassic magmas in southeast Colorado, USAProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 136-138ColoradoGeochemistry, Petrography, minettes
DS1991-1724
1991
Gibson, S.A.Thompson, R.N., Gibson, S.A.Subcontinental mantle plumes, hotspots and pre-existing thinspotsJournal of the Geological Society of London, Vol. 248, November pp. 973-977MantlePlumes, Hotspots
DS1991-1725
1991
Gibson, S.A.Thompson, R.N., Gibson, S.A., Leat, P.T.Overt and cryptic strongly potassic mafic liquids in the Neogene magmatism of the n.part of the Rio Grande Rift, USA: a lithospheric drip feed into asthenospheric soProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 420-422Arizona, Colorado PlateauPotassic lavas, basalts, Minette, Lamproite, Elkhead Mts.Leucite Hills
DS1992-0565
1992
Gibson, S.A.Gibson, S.A., Thompson, R.N., Leat, P.T., Dickin, A.P., MorrisonAsthenosphere-derived magmatism in the Rio Grande rift, westerm USA:implications for continental break upGeological Society Special Publication Magmatism and the causes of the continental, No. 68, pp. 61-89Cordillera, Arizona, New MexicoTectonics, Rifting
DS1993-0540
1993
Gibson, S.A.Gibson, S.A., Leonardos, O.H., Thompson, R.N., Turner, S.E.O diatrema alcalino-ultrafico da Serra do Bueno, Alto Paranaiba MinasGerais. (in Portugese).Brasiliao Geologi do Diamante UFMT., Esp. 2/93, Cuabe, pp. 57-78.BrazilKimberlites, mafic ultrapotassic rocks, alkaline rocks, Serra do Bueno
DS1993-0541
1993
Gibson, S.A.Gibson, S.A., Thompson, R.N., Leat, P.T., Morrison, M.A., HendryUltrapotassic magmas along the flanks of the Oligo-Miocene Rio GrandeJournal of Petrology, Vol. 34, No. 1, February pp. 187-228Mantle, Colorado PlateauUltrapotassic, Tectonics
DS1993-1569
1993
Gibson, S.A.Tallarico, F.H.B., Leonardos, O.H., Gibson, S.A., Meyer, H.O.A.Quimica mineral da intrusa o da mat a do lenco, Abadia dos Dourados, MinasGerais.(in Portugese).Brasiliao Geologi do Diamante UFMT., Esp. 2/93, Cuabe, pp. 114-128.BrazilDa Mata do Lenco, Kimberlitic intrusive
DS1994-0618
1994
Gibson, S.A.Gibson, S.A.Ultrapotassic magmatic key to interaction of Cretaceous mantle plumes with laterally heterogeneous South AmericanEos, Annual Meeting November 1, Vol. 75, No. 44, p.722. abstractBrazil, South AmericaUltrapotassic, Alkaline rocks
DS1994-0619
1994
Gibson, S.A.Gibson, S.A., Thompson, R.N., Leonardo, O.H., Turner, S.The Serra do Bueno potassic diatreme - a possible hypabyssal equiv. of ultramafic alkaline volcanics.Mineralogical Magazine, Vol. 58, No. 392, Sept. 357-373.BrazilAlkaline rocks, Diatremes
DS1994-0620
1994
Gibson, S.A.Gibson, S.A., Thompson, R.N., Leonardos, O.H., Dickin, A.The late Cretaceous impact of the Trindade plume: evidence from large volume mafic potassic magmatism.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 56-58.BrazilMantle plume, Alkaline rocks
DS1994-1769
1994
Gibson, S.A.Thompson, R.N., Gibson, S.A.Magmatic expression of lithospheric thinning across continental riftsTectonophysics, Vol. 233, No. 1-2, May 15, pp. 41-68.MantleTectonics, Magma
DS1994-1770
1994
Gibson, S.A.Thompson, R.N., Gibson, S.A.Interplay between lithospheric and convecting mantle sources during continental rift related magmatism.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 115-117.United States, Colorado, New Mexico, East Africa, Russia, BaikalMantle, Tectonics, magma
DS1995-0630
1995
Gibson, S.A.Gibson, S.A., Thompson, R.N., Leonardos, G.H., DickinThe late Cretaceous impact of the Trindade mantle plume; evidence from large volume, mafic potassic MagazineJournal of Petrology, Vol. 36, No. 1, February, pp. 189-229.BrazilMagmatism -potassic, Alkaline rocks
DS1995-0631
1995
Gibson, S.A.Gibson, S.A., Thompson, R.N., Leonardos, O.H., Dickin, A.P.The Late Cretaceous impact of the Trindada mantle plume: evidence large volume mafic potassic magmatismJournal of Petrology, Vol. 36, No. 1, Feb. pp. 189-230.BrazilMagmatism -potassic, Alkaline rocks
DS1995-1085
1995
Gibson, S.A.Leonardos, O.H., Carvalho, J.B., Gibson, S.A., ThompsonThe diamond potential of the late Cretaceous Alto Paranaiba igneousprovince, Brasil.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 320-322.BrazilAlluvials, Deposit -Alto Paranaiba
DS1996-0522
1996
Gibson, S.A.Gibson, S.A., Thompson, R.N., Dickin, A.P., Leonardos, O.Erratum to High Ti and low Ti mafic potassic magmas: Key to plume lithosphere interactions and flood genesisEarth and Planetary Science Letters, Vol. 141, pp. 325-341Brazil, ParaguayMagmas, Lithosphere
DS1996-0523
1996
Gibson, S.A.Gibson, S.A., Thomspon, R.N., Leonardos, O.H.Erratun to high Ti and low Ti mafic potassic magmas: key to plume lithosphere interactions ...Earth and Planetary Science Letters, Vol. 141, No. 1-4, June 1, pp. 325-MantleAlkaline rocks, Plumes
DS1997-0399
1997
Gibson, S.A.Gibson, S.A., Thompson, R.N., Weska, R.K., Dickin, A.P.Late Cretaceous rift related upwelling and melting of the Trindade starting mantle plume head beneath Brasil.Contributions to Mineralogy and Petrology, Vol. 126, pp. 303-314.BrazilMantle plume, Tectonics
DS1997-0400
1997
Gibson, S.A.Gibson, S.A., Thompson, R.N., Weska, R.K., Dickin, A.P.Late Cretaceous rift related upwelling and melting of the Trindada starting mantle plume head western BrasilContributions to Mineralogy and Petrology, Vol. 126, pp. 303-314BrazilTrindade Mantle, Sao Francisco Craton
DS1998-0231
1998
Gibson, S.A.Chalapthi Rao, N.V., Gibson, S.A., Dickin, A.P.Contrasting isotopic mantle sources for Proterozoic lamproites And kimberlites Cuddapah Basin, Dharwar Craton #1Journal of Geological Society India, Vol. 52, No. 6, Dec. pp. 683-94.India, South IndiaGeochronology, ages, Phanerozoic mantle heterogeneity
DS1998-0506
1998
Gibson, S.A.Gibson, S.A., Thompson, R.N., Dickin, A.P.Subcontinental mantle plume impact and kimberlite genesis7th International Kimberlite Conference Abstract, pp. 250-2.Angola, Brazil, Namibia, ParaguayMantle plume, Deposit - Lunda area
DS1998-0531
1998
Gibson, S.A.Greenwood, J.C., Gibson, S.A., Thompson, R.N., WeskaPetrogenesis of Cretaceous kimberlites from the Paranatinga region, centralBrasil.7th International Kimberlite Conference Abstract, pp. 268-270.BrazilGeochemistry, petrology, Deposit - Paratinga
DS2000-0109
2000
Gibson, S.A.Brod, J.A., Gibson, S.A., Thompson, R., Junqueira-BrodMineral chemistry fingerprints of liquid immiscibility and fractionation in the Tapira alkaline - carbonatiteIgc 30th. Brasil, Aug. abstract only 1p.Brazil, Minas GeraisCarbonatite - Alto Paranaiba Igneous Province
DS2000-0110
2000
Gibson, S.A.Brod, J.A., Gibson, S.A., Thompson, R., Junqueira-BrodKamafugite affinity of the Tapira alkaline carbonatite complex (Minas Gerais, Brasil).Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Minas GeraisCarbonatite - Araxa, Serra Negra, Salitre, Catalao, Kamafugites
DS2000-0336
2000
Gibson, S.A.Gibson, S.A., Thompson, Dickin, LeonardosCarbonatite and kimberlite magmatism asssociated wiht the impact of the Proto-Tristan plume.Igc 30th. Brasil, Aug. abstract only 1p.BrazilParan-Etendeka igneous
DS2000-0953
2000
Gibson, S.A.Thompson, R.N., Gibson, S.A.Transient high temperature in mantle plume heads inferred from magnesian olivines Phanerozoic picritesNature, Vol. 407, No. 6803, Sept. 28, pp. 502-5.MantlePlumes, hot spots, Picrites
DS2001-1155
2001
Gibson, S.A.Thompson, R.N., Gibson, S.A., Dickin, A.P., Smith, P.M.Early Cretaceous basalt and picrite dykes of southern Etendeka Province: windows into role Tristan mantle ...Jour. Petrol., Vol. 42, No. 11, pp. 2049-82.NamibiaPlume - Parana - Etendeka magmatism, Picrite dikes
DS2002-0567
2002
Gibson, S.A.Gibson, S.A.Major element heterogeneity in Archean to recent mantle plume starting headsEarth and Planetary Science Letters, Vol. 195, No. 1-2, pp. 59-74.South Africa, Ontario, Manitoba, SiberiaPicrites, komatiites, flood basalts, eclogite, Lithosphere
DS2003-0013
2003
Gibson, S.A.Anand, M., Gibson, S.A., Subbarao, K.V., Kelley, S.P., Dickin, A.P.Early Proterozoic melt generation processes beneath the intra-cratonic CuddapahJournal of Petrology, Vol. 44, 12, pp. 2139-2172.IndiaMetasomatism
DS2003-0168
2003
Gibson, S.A.Brod, J.A., Junqueira-Brod, T.C., Gaspar, J.C., Gibson, S.A., Thompson, R.N.Ti rich and Ti poor garnet from the Tapira carbonatite complex, SE Brazil: fingerprinting8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractBrazil, Minas GeraisBlank
DS200412-0025
2003
Gibson, S.A.Anand, M., Gibson, S.A., Subbarao, K., Kelly, S.P., Dickin, A.P.Early Proterozoic melt generation processes beneath the intra cratonic Cuddapah Basin, southern India.Journal of Petrology, Vol. 44, pp. 2139-2171.IndiaCraton, melting
DS200412-0026
2003
Gibson, S.A.Anand, M., Gibson, S.A., Subbarao, K.V., Kelley, S.P., Dickin, A.P.Early Proterozoic melt generation processes beneath the intra-cratonic Cuddapah Basin, southern India.Journal of Petrology, Vol. 44, 12, pp. 2139-2172.IndiaMetasomatism
DS200412-0214
2003
Gibson, S.A.Brod, J.A., Junqueira-Brod, T.C., Gaspar, J.C., Gibson, S.A., Thompson, R.N.Ti rich and Ti poor garnet from the Tapira carbonatite complex, SE Brazil: fingerprinting fractional crystallization and liquid8 IKC Program, Session 7, POSTER abstractSouth America, Brazil, Minas GeraisKimberlite petrogenesis
DS200412-0304
2004
Gibson, S.A.Chalapathi Rao, N.V., Gibson, S.A., Pyle, D.M., Dickin, A.P.Petrogenesis of Proterozoic lamproites and kimberlites from the Cuddapah Basin and Dharwar Craton, southern India.Journal of Petrology, Vol. 45, 5, pp. 907-948.IndiaLamproites - Mahbubnagar, Anantapur, diamonds
DS200512-0480
2005
Gibson, S.A.Johnson, J.S., Gibson, S.A., Thompson, R.N., Nowell, G.M.Volcanism in the Vitim volcanic field, Siberia: geochemical evidence for a mantle plume beneath the Baikal Rift zone.Journal of Petrology, Vol. 46, 7, July pp. 1309-1344.Russia, SiberiaGeochemistry - Vitim
DS200512-0481
2005
Gibson, S.A.Johnson, J.S., Gibson, S.A., Thompson, R.N., NOwell, G.M.Volcanism in the Vitim volcanic field, Siberia: geochemical evidence for a mantle plume beneath the Baikal Rift Zone.Journal of Petrology, Vol. 46, pp. 1309-1344.Russia, SiberiaPlume
DS200512-1084
2005
Gibson, S.A.Thompson, R.N., Ottley, C.J., Smith, P.M., Pearson, D.G., Dickin, A.P., Morrison, M.A., Leat, P.T., Gibson, S.A.Source of the Quaternary alkalic basalts, picrites and basanites of the Potrillo volcanic field, New Mexico, USA: lithosphere or convecting mantle?Journal of Petrology, Vol. 46, 8, pp. 1603-1643.United States, New Mexico, Colorado PlateauConvection
DS200512-1085
2005
Gibson, S.A.Thompson, R.N., Ottley, C.J., Smith, P.M., Pearson, D.G., Dickin, A.P., Morrison, M.A., Leat, P.T., Gibson, S.A.Source of the Quaternary alkaline basalts, picrites and basanites of the Potrillo volcanic field, New Mexico, USA: lithosphere or convecting mantle?Journal of Petrology, Vol. 46, 8, pp. 1603-1643.United States, New Mexico, Colorado PlateauPicrite, basanites
DS200512-1105
2005
Gibson, S.A.Tuff, J., Takahashi, E., Gibson, S.A.Experimental constraints on the role of garnet pyroxenite in the genesis of high Fe mantle plume derived melts.Journal of Petrology, Vol. 46, 10, pp. 2023-2058.MantleMelting
DS200512-1106
2005
Gibson, S.A.Tuff, J., Takahasi, E., Gibson, S.A.Experimental constraints on the role of garnet pyroxenite in the genesis of high Fe mantle plume derived melts.Journal of Petrology, Vol. 46. 10, Oct. pp. 2023-2058.MantleGarnet pyroxenite melting
DS200612-1444
2006
Gibson, S.A.Tuff, J., Gibson, S.A.3-7 GPa trace element partitioning in Fe rich picrites.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 26, abstract only.MantlePicrite
DS200712-0360
2006
Gibson, S.A.Gibson, S.A., Thompson, R.N., Day, J.A.Timescales and mechanisms of plume-lithosphere interactions: Ar/Ar geochronology and geochemistry of alkaline igneous rocks from the Parana Etendeka igneousEarth and Planetary Science Letters, Vol. 251, 1-2, Nov. 15, pp. 1-17.South America, BrazilGeochronology
DS200712-1095
2007
Gibson, S.A.Tuff, J., Gibson, S.A.Trace element partioning between garnet, clinopyroxene and Fe rich picritic melts at 3 to 7 GPa.Contributions to Mineralogy and Petrology, Vol. 153, 4, pp. 369-387.TechnologyPicrite
DS200812-0408
2008
Gibson, S.A.Gibson, S.A., Malarkey, J., Day, J.A.Melt depletion and enrichment beneath the western Kaapvaal Craton: evidence from Finsch peridotite xenoliths.Journal of Petrology, Vol. 49, 10, pp. 1817-1852.Africa, South AfricaDeposit - Finsch
DS201312-0310
2013
Gibson, S.A.Gibson, S.A., McMahon, S.C., Day, J.A., Dawson, J.B.Highly refractory lithospheric mantle beneath the Tanzanian Craton: evidence from Lashaine pre-metasomatic garnet bearing peridotites.Journal of Petrology, Vol. 54, 8, pp. 1503-1546.Africa, TanzaniaLashaine peridotites
DS201412-0290
2014
Gibson, S.A.Gibson, S.A.Continental rifting and mantle exotica.Volcanic and Magmatic Studies Group meeting, Abstract only Held Jan. 6-8. See minsoc websiteMantleRifting
DS201412-0586
2014
Gibson, S.A.Miller, W.G.R., Holland, T.J.B., Gibson, S.A.Multiple reaction oxygen barometry for mantle peridotite: an internally consistent thermodynamic model for reactions and garnet solid-solutions, with applications to the oxidation state of lithospheric mantle.Volcanic and Magmatic Studies Group meeting, Poster Held Jan. 6-8. See minsoc websiteMantleThermobarometry
DS201412-0751
2014
Gibson, S.A.Rooks, E.E., Gibson, S.A.Evolution of the SCLM beneath Pali Aike from mantle xenoliths.Volcanic and Magmatic Studies Group meeting, Poster Held Jan. 6-8. See minsoc websiteSouth America, PatagoniaXenoliths
DS201605-0880
2016
Gibson, S.A.Neave, D.A., Black, M., Riley, T.R., Gibson, S.A., Ferrier, G., Wall, F., Broom-Fendley, S.On the feasibility of imaging carbonatite-hosted rare earth element deposits using remote sensing.Economic Geology, Vol. 111, pp. 641-665.China, United States, Europe, GreenlandDeposit - Bayan Obo, Mountain Pass, Motzfeldt, Ilimaussaq

Abstract: Rare earth elements (REEs) generate characteristic absorption features in visible to shortwave infrared (VNIR-SWIR) reflectance spectra. Neodymium (Nd) has among the most prominent absorption features of the REEs and thus represents a key pathfinder element for the REEs as a whole. Given that the world’s largest REE deposits are associated with carbonatites, we present spectral, petrographic, and geochemical data from a predominantly carbonatitic suite of rocks that we use to assess the feasibility of imaging REE deposits using remote sensing. Samples were selected to cover a wide range of extents and styles of REE mineralization, and encompass calcio-, ferro- and magnesio-carbonatites. REE ores from the Bayan Obo (China) and Mountain Pass (United States) mines, as well as REE-rich alkaline rocks from the Motzfeldt and Ilímaussaq intrusions in Greenland, were also included in the sample suite. The depth and area of Nd absorption features in spectra collected under laboratory conditions correlate positively with the Nd content of whole-rock samples. The wavelength of Nd absorption features is predominantly independent of sample lithology and mineralogy. Correlations are most reliable for the two absorption features centered at ~744 and ~802 nm that can be observed in samples containing as little as ~1,000 ppm Nd. By convolving laboratory spectra to the spectral response functions of a variety of remote sensing instruments we demonstrate that hyperspectral instruments with capabilities equivalent to the operational Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) and planned Environmental Mapping and Analysis Program (EnMAP) systems have the spectral resolutions necessary to detect Nd absorption features, especially in high-grade samples with economically relevant REE accumulations (Nd > 30,000 ppm). Adding synthetic noise to convolved spectra indicates that correlations between Nd absorption area and whole-rock Nd content only remain robust when spectra have signal-to-noise ratios in excess of ~250:1. Although atmospheric interferences are modest across the wavelength intervals relevant for Nd detection, most REE-rich outcrops are too small to be detectable using satellite-based platforms with >30-m spatial resolutions. However, our results indicate that Nd absorption features should be identifiable in high-quality, airborne, hyperspectral datasets collected at meter-scale spatial resolutions. Future deployment of hyperspectral instruments on unmanned aerial vehicles could enable REE grade to be mapped at the centimeter scale across whole deposits.
DS201608-1424
2016
Gibson, S.A.Miller, W.G.R., Holland, T.J.B., Gibson, S.A.Garnet and spinel oxybarometers: new internally consistent multi-equilibration temperatures models with applications to the oxidation state of the lithospheric mantle.Journal of Petrology, Vol. 57, 6, pp. 1199-1222.MantleGeobarometry

Abstract: New thermodynamic data for skiagite garnet (Fe3Fe23+Si3O12) are derived from experimental phase-equilibrium data that extend to 10 GPa and are applied to oxybarometry of mantle peridotites using a revised six-component garnet mixing model. Skiagite is more stable by 12 kJ mol-1 than in a previous calibration of the equilibrium 2 skiagite = 4 fayalite + ferrosilite + O2, and this leads to calculated oxygen fugacities that are higher (more oxidized) by around 1-1•5 logfO2 units. A new calculation method and computer program incorporates four independent oxybarometers (including 2 pyrope + 2 andradite + 2 ferrosilite = 2 grossular + 4 fayalite + 3 enstatite + O2) for use on natural peridotite samples to yield optimum logfO2 estimates by the method of least squares. These estimates should be more robust than those based on any single barometer and allow assessment of possible disequilibrium in assemblages. A new set of independent oxybarometers for spinel-bearing peridotites is also presented here, including a new reaction 2 magnetite + 3 enstatite = 3 fayalite + 3 forsterite + O2. These recalibrations combined with internally consistent PT determinations for published analyses of mantle peridotites with analysed Fe2O3 data for garnets, from both cratonic (Kaapvaal, Siberia and Slave) and circumcratonic (Baikal Rift) regions, provide revised estimates of oxidation state in the lithospheric mantle. Estimates of logfO2 for spinel assemblages are more reduced than those based on earlier calibrations, whereas garnet-bearing assemblages are more oxidized. Importantly, this lessens considerably the difference between garnet and spinel oxybarometry that was observed with previous published calibrations.
DS201610-1875
2016
Gibson, S.A.Jennings, E.S., Gibson, S.A., Maclennan, J., Heinonen, J.S.Deep mixing of mantle melts beneath continental flood basalt provinces: constraints from olivine hosted melt inclusions in primitive magmas. Etendeka and KarooGeochimica et Cosmochimica Acta, in press availableAfrica, NamibiaPicrite, ferroPicrite

Abstract: We present major and trace element compositions of 154 re-homogenised olivine-hosted melt inclusions found in primitive rocks (picrites and ferropicrites) from the Mesozoic Paraná-Etendeka and Karoo Continental Flood Basalt (CFB) provinces. The major element compositions of the melt inclusions, especially their Fe/Mg ratios, are variable and erratic, and attributed to the re-homogenisation process during sample preparation. In contrast, the trace element compositions of both the picrite and ferropicrite olivine-hosted melt inclusions are remarkably uniform and closely reflect those of the host whole-rocks, except in a small subset affected by hydrothermal alteration. The Paraná-Etendeka picrites and ferropicrites are petrogenetically related to the more evolved and voluminous flood basalts, and so we propose that compositional homogeneity at the melt inclusion scale implies that the CFB parental mantle melts were well mixed prior to extensive crystallisation. The incompatible trace element homogeneity of olivine-hosted melt inclusions in Paraná-Etendeka and Karoo near primitive magmatic rocks has also been identified in other CFB provinces and contrasts with findings from studies of basalts from mid-ocean ridges (e.g. Iceland and FAMOUS on the Mid Atlantic Ridge), where heterogeneity of incompatible trace elements in olivine-hosted melt inclusions is much more pronounced. We suggest that the low variability in incompatible trace element contents of olivine-hosted melt inclusions in near-primitive CFB rocks, and also ocean island basalts associated with moderately thick lithosphere (e.g. Hawaii, Galápagos, Samoa) may reflect mixing along their longer transport pathways during ascent and/or a temperature contrast between the liquidus and the liquid when it arrives in the crust. These thermal paths promote mixing of mantle melts prior to their entrapment by growing olivine crystals in crustal magma chambers. Olivine-hosted melt inclusions of ferropicrites from the Paraná-Etendeka and Karoo CFB have the least variable compositions of all global melt inclusion suites, which may be a function of their unusually deep origin and low viscosity.
DS201611-2115
2016
Gibson, S.A.Jennings, E.S., Gibson, S.A., Maclennan, J., Heinonen, J.S.Deep mantle melts beneath continental flood basalt provinces: constraints from olivine hosted melt inclusions in primitive magmas.Geochimica et Cosmochimica Acta, Vol. 196, pp. 36-57.Africa, Namibia, AngolaParan-Etendeka, Karoo

Abstract: We present major and trace element compositions of 154 re-homogenised olivine-hosted melt inclusions found in primitive rocks (picrites and ferropicrites) from the Mesozoic Parana ´-Etendeka and Karoo Continental Flood Basalt (CFB) provinces. The major element compositions of the melt inclusions, especially their Fe/Mg ratios, are variable and erratic, and attributed to the re-homogenisation process during sample preparation. In contrast, the trace element compositions of both the picrite and ferropicrite olivine-hosted melt inclusions are remarkably uniform and closely re?ect those of the host whole-rocks, except in a small subset a?ected by hydrothermal alteration. The Parana ´-Etendeka picrites and ferropicrites are petrogenet- ically related to the more evolved and voluminous ?ood basalts, and so we propose that compositional homogeneity at the melt inclusion scale implies that the CFB parental mantle melts were well mixed prior to extensive crystallisation. The incompatible trace element homogeneity of olivine-hosted melt inclusions in Parana ´-Etendeka and Karoo primitive magmatic rocks has also been identi?ed in other CFB provinces and contrasts with ?ndings from studies of basalts from mid- ocean ridges (e.g. Iceland and FAMOUS on the Mid Atlantic Ridge), where heterogeneity of incompatible trace elements in olivine-hosted melt inclusions is more pronounced. We suggest that the low variability in incompatible trace element contents of olivine-hosted melt inclusions in near-primitive CFB rocks, and also ocean island basalts associated with moderately thick lithosphere (e.g. Hawaii, Gala ´pagos, Samoa), may re?ect mixing along their longer transport pathways during ascent and/or a temperature contrast between the liquidus and the liquid when it arrives in the crust. These thermal paths promote mixing of mantle melts prior to their entrapment by growing olivine crystals in crustal magma chambers. Olivine-hosted melt inclusions of ferropicrites from the Parana ´-Etendeka and Karoo CFB have the least variable compositions of all global melt inclusion suites, which may be a function of their unusually deep origin and low viscosity.
DS201704-0629
2017
Gibson, S.A.Jennings, E.S., Holland, T.J.B., Maclennan, J., Gibson, S.A.The composition of melts from a heterogeneous mantle and the origin of ferropicrite: application of a thermodynamic model.Journal of Petrology, Vol. 57, 11-12, pp. 2289-2310.MantleGeochemistry
DS201708-1570
2017
Gibson, S.A.Gibson, S.A.On the nature and origin of garnet in highly refractory Archean lithospheric mantle: constraints from garnet exsolved in Kaapvaal craton orthopyroxenes.Mineralogical Magazine, Vol. 81, 4, pp. 781-809.Africa, South Africagarnet

Abstract: The widespread occurrence of pyrope garnet in Archean lithospheric mantle remains one of the ‘holy grails’ of mantle petrology. Most garnets found in peridotitic mantle equilibrated with incompatible-trace-element-enriched melts or fluids and are the products of metasomatism. Less common are macroscopic intergrowths of pyrope garnet formed by exsolution from orthopyroxene. Spectacular examples of these are preserved in both mantle xenoliths and large, isolated crystals (megacrysts) from the Kaapvaal craton of southern Africa, and provide direct evidence that some garnet in the sub-continental lithospheric mantle initially formed by isochemical rather than metasomatic processes. The orthopyroxene hosts are enstatites and fully equilibrated with their exsolved phases (low-Cr pyrope garnet ±± Cr-diopside). Significantly, P-TP-T estimates of the post-exsolution orthopyroxenes plot along an unperturbed conductive Kaapvaal craton geotherm and reveal that they were entrained from a large continuous depth interval (85 to 175 km). They therefore represent snapshots of processes operating throughout almost the entire thickness of the sub-cratonic lithospheric mantle. New rare-earth element (REE) analyses show that the exsolved garnets occupy the full spectrum recorded by garnets in mantle peridotites and also diamond inclusions. A key finding is that a few low-temperature exsolved garnets, derived from depths of ~90 km, are more depleted in light REEs than previously observed in any other mantle sample. Importantly, the REE patterns of these strongly LREE-depleted garnets resemble the hypothetical composition proposed for pre-metasomatic garnets that are thought to pre-date major enrichment events in the sub-continental lithospheric mantle, including those associated with diamond formation. The recalculated compositions of pre-exsolution orthopyroxenes have higher Al22O33 and CaO contents than their post-exsolution counterparts and most likely formed as shallow residues of large amounts of adiabatic decompression melting in the spinel-stability field. It is inferred that exsolution of garnet from Kaapvaal orthopyroxenes may have been widespread, and perhaps accompanied cratonization at ~ 2.9 to 2.75 Ga. Such a process would considerably increase the density and stability of the continental lithosphere.
DS201709-1987
2017
Gibson, S.A.Gibson, S.A.On the nature and origin of garnet in highly refractory Archean lithospheric mantle: constraints from garnet exsolved in Kaapvaal craton orthopyroxenes.Mineralogical Magazine, Vol. 81, 4, pp. 781-809.Africa, South Africagarnet mineralogy

Abstract: The widespread occurrence of pyrope garnet in Archean lithospheric mantle remains one of the ‘holy grails’ of mantle petrology. Most garnets found in peridotitic mantle equilibrated with incompatible-trace-element-enriched melts or fluids and are the products of metasomatism. Less common are macroscopic intergrowths of pyrope garnet formed by exsolution from orthopyroxene. Spectacular examples of these are preserved in both mantle xenoliths and large, isolated crystals (megacrysts) from the Kaapvaal craton of southern Africa, and provide direct evidence that some garnet in the sub-continental lithospheric mantle formed initially by isochemical rather than metasomatic processes. The orthopyroxene hosts are enstatites and fully equilibrated with their exsolved phases (low-Cr pyrope garnet?±?Cr-diopside). Significantly, P-T estimates of the post-exsolution orthopyroxenes plot along an unperturbed conductive Kaapvaal craton geotherm and reveal that they were entrained from a large continuous depth interval (85 to 175?km). They therefore represent snapshots of processes operating throughout almost the entire thickness of the sub-cratonic lithospheric mantle. New rare-earth element (REE) analyses show that the exsolved garnets occupy the full spectrum recorded by garnets in mantle peridotites and also diamond inclusions. A key finding is that a few low-temperature exsolved garnets, derived from depths of ?90?km, are more depleted in light rare-earth elements (LREEs) than previously observed in any other mantle sample. Importantly, the REE patterns of these strongly LREE-depleted garnets resemble the hypothetical composition proposed for pre-metasomatic garnets that are thought to pre-date major enrichment events in the sub-continental lithospheric mantle, including those associated with diamond formation. The recalculated compositions of pre-exsolution orthopyroxenes have higher Al2O3 and CaO contents than their post-exsolution counterparts and most probably formed as shallow residues of large amounts of adiabatic decompression melting in the spinel-stability field. It is inferred that exsolution of garnet from Kaapvaal orthopyroxenes may have been widespread, and perhaps accompanied cratonization at ?2.9 to 2.75 Ga. Such a process would considerably increase the density and stability of the continental lithosphere.
DS201809-2026
2018
Gibson, S.A.Gibson, S.A., Richards, M.A.Delivery of deep sourced, volatile rich plume material to the global ridge system.Earth and Planetary Science Letters, Vol. 499, pp. 205-218.Oceanplumes, hotspots

Abstract: The global mid-ocean ridge (MOR) system represents a major site for outgassing of volatiles from Earth's mantle. The amount of H2O released via eruption of mid-ocean ridge basalts varies along the global ridge system and greatest at sites of interaction with mantle plumes. These deep-sourced thermal anomalies affect approximately one-third of all MORs - as reflected in enrichment of incompatible trace elements, isotope signatures and elevated ridge topography (excess melting) - but the physical mechanisms involved are controversial. The “standard model” involves solid-state flow interaction, wherein an actively upwelling plume influences the divergent upwelling generated by a mid-ocean ridge so that melting occurs at higher pressures and in greater amounts than at a normal spreading ridge. This model does not explain, however, certain enigmatic features including linear volcanic ridges radiating from the active plume to the nearby MOR. Examples of these are the Wolf-Darwin lineament (Galápagos), Rodrigues Ridge (La Réunion), Discovery Ridge (Discovery), and numerous smaller ridge-like structures associated with the Azores and Easter-Salas y Gómez hot spots. An important observation from our study is that fractionation-corrected MORB with exceptionally-high H2O contents (up to 1.3 wt.%) are found in close proximity to intersections of long-lived plume-related volcanic lineaments with spreading centres. New algorithms in the rare-earth element inversion melting (INVMEL) program allow us to simulate plume-ridge interactions by mixing the compositions of volatile-bearing melts generated during both active upwelling and passively-driven corner-flow. Our findings from these empirical models suggest that at sites of plume-ridge interaction, moderately-enriched MORBs (with 0.2-0.4 wt.% H2O) result from mixing of melts formed by: (i) active upwelling of plume material to minimum depths of ?35 km; and (ii) those generated by passive melting at shallower depths beneath the ridge. The most volatile-rich MORB (0.4-1.3 wt.% H2O) may form by the further addition of up to 25% of “deep” small-fraction plume stem melts that contain >3 wt.% H2O. We propose that these volatile-rich melts are transported directly to nearby MOR segments via pressure-induced, highly-channelised flow embedded within a broader “puddle” of mostly solid-state plume material, spreading beneath the plate as a gravity flow. This accounts for the short wavelength variability (over 10s of km) in geochemistry and bathymetry that is superimposed on the much larger (many 100s of km) “waist width” of plume-influenced ridge. Melt channels may constitute a primary delivery mechanism for volatiles from plume stems to nearby MORs and, in some instances, be expressed at the surface as volcanic lineaments and ridges. The delivery of small-fraction hydrous melts from plume stems to ridges via a two-phase (melt-matrix) regime implies that a parallel, bimodal transport system is involved at sites of plume-ridge interaction. We estimate that the rate of emplacement of deep-sourced volatile-rich melts in channels beneath the volcanic lineaments is high and involves 10s of thousands of km3/Ma. Since mantle plumes account for more than half of the melt production at MORs our findings have important implications for our understanding of deep Earth volatile cycling.
DS201810-2331
2018
Gibson, S.A.Jackson, C.G., Gibson, S.A.Preservation of systematic Ni and Cr heterogeneity in otherwise homogeneous mantle olivine: implications for timescales of post-metasomatism re-equilibration.Lithos, Vol. 318-319. pp. 448-463.Africa, South Africadeposit - Bultfontein

Abstract: The flux of elements into Earth's sub-continental lithospheric mantle is facilitated by the passage of small-fraction melts that either crystallise new phases or react with pre-existing minerals.Metasomatised peridotite records the end product of this exchange but rarely captures the process in the act due to subsolidus re-equilibration. We present the results of a systematic investigation of a metasomatic melt channel preserved in a mantle peridotite from the Late Cretaceous Bultfontein kimberlite (Kaapvaal craton) that shows rare direct evidence of the melt-rock reaction processes. We show that the metasomatic proto-kimberlite melt underwent variable crystallisation of clinopyroxene, sulfides, phlogopite, spinel and zircon together with interaction and diffusive exchange with the surrounding olivine-rich mantle. Element profiles across large olivine porphyroclasts (Fo88) show significant core-to-rim variations in Ni (NiO?=?0.18-0.32?wt%) and Cr (Cr?=?35-60?ppm), while concentrations of all other elements (e.g. Mg, Fe, Mn, Co, V)are remarkably homogeneous. Electron backscatter diffraction analysis shows that the disequilibrium of Ni and Cr is greatest where the crystal contains large components of the [100] and [010] axes. The disequilibrium is preserved in certain orientations because diffusion of Ni and Cr in olivine is more anisotropic than Fe-Mg and Mn, and slower in the [100] and [010] directions. We present the first observations of Ni and Cr decoupling from other elements in mantle olivine and suggest that this is a consequence of: (i)changing mineral-melt concentration gradients associated with the reactive percolation of a precursory kimberlite melt; and (ii) late-stage sulfide and spinel precipitation. We use the diffusion limited re-equilibration of Ni in olivine to quantify the timing of metasomatism prior to xenolith entrainment by the host kimberlite. Our modelling indicates that reactive percolation occurred on the order of 103-105?years prior to entrainment; this provides an additional line of support for the hypothesis that a period of metasomatism by proto-kimberlite melts precedes the final kimberlite ascent to the surface. The broader implication of our finding of variable rates of minor element diffusion in natural olivine is that it highlights the importance of anisotropy and the impact of changing local concentration gradients during subsolidus re-equilibration.
DS201812-2821
2018
Gibson, S.A.Jackson, C.G., Gibson, S.A.Preservation of systematic Ni and Cr heterogeneity in otherwise homogeneous mantle olivine: implications for timescales of post-metasomatism re-equilibrium.Lithos, Vol. 318-319, pp. 448-463.Africa, South Africadeposit - Bultfontein

Abstract: The flux of elements into Earth’s sub-continental lithospheric mantle is facilitated by the passage of small-fraction melts that either crystallise new phases or react with pre-existing minerals. Metasomatised peridotite records the end product of this exchange but rarely captures the process in the act due to subsolidus re-equilibration. We present the results of a systematic investigation of a metasomatic melt channel preserved in a mantle peridotite from the Late Cretaceous Bultfontein kimberlite (Kaapvaal craton) that shows rare direct evidence of the melt-rock reaction processes. We show that the metasomatic proto-kimberlite melt underwent variable crystallisation of clinopyroxene, sulfides, phlogopite, spinel and zircon together with interaction and diffusive exchange with the surrounding olivine-rich mantle. Element profiles across large olivine porphyroclasts (Fo88) show significant core-to-rim variations in Ni (NiO = 0.18-0.32 wt.%) and Cr (Cr = 35-60 ppm), while concentrations of all other elements (e.g. Mg, Fe, Mn, Co, V) are remarkably homogeneous. Electron backscatter diffraction analysis shows that the disequilibrium of Ni and Cr is greatest where the crystal contains large components of the [100] and [010] axes. The disequilibrium is preserved in certain orientations because diffusion of Ni and Cr in olivine is more anisotropic than Fe-Mg and Mn, and slower in the [100] and [010] directions. We present the first observations of Ni and Cr decoupling from other elements in mantle olivine and suggest that this is a consequence of: (i) changing mineral-melt concentration gradients associated with the reactive percolation of a precursory kimberlite melt; and (ii) late-stage sulfide and spinel precipitation. We use the diffusion limited re-equilibration of Ni in olivine to quantify the timing of metasomatism prior to xenolith entrainment by the host kimberlite. Our modelling indicates that reactive percolation occurred on the order of 103-105 years prior to entrainment; this provides an additional line of support for the hypothesis that a period of metasomatism by proto-kimberlite melts precedes the final kimberlite ascent to the surface. The broader implication of our finding of variable rates of minor element diffusion in natural olivine is that it highlights the importance of anisotropy and the impact of changing local concentration gradients during subsolidus re-equilibration.
DS201908-1815
2019
Gibson, S.A.Shu, Q, Brey, G.P., Pearson, G., Liu, J., Gibson, S.A., Becker, H.The evolution of the Kaapvaal craton: a multi-isotopic perspective from lithospheric peridotites from Finsch diamond mine.Precambrian Research, 105380, 21p. PdfAfrica, South Africadeposit - Finsch

Abstract: Accurately dating the formation and modification of Earth’s sub-cratonic mantle still faces many challenges, primarily due to the long and complex history of depletion and subsequent metasomatism of this reservoir. In an attempt to improve this, we carried out the first study on peridotites from the Kaapvaal craton (Finsch Mine) that integrates results from Re-Os, Lu-Hf, Sm-Nd and Sr-isotope systems together with analyses of major-, trace- and platinum-group elements. The Finsch peridotites are well-suited for such a study because certain compositional features reflect they were highly depleted residues of shallow melting (1.5?GPa) at ambient Archean mantle temperatures. Yet, many of them have overabundant orthopyroxene, garnet and clinopyroxene compared to expected modal amounts for residues from partial melting. Finsch peridotites exhibit a wide range of rhenium depletion ages (TRD) from present day to 2.7?Ga, with a prominent mode at 2.5?Ga. This age overlaps well with a Lu-Hf isochron of 2.64?Ga (?Hf (t)?=?+26) which records silico-carbonatitic metasomatism of the refractory residues. This late Archean metasomatism is manifested by positive correlations of Pt/Ir and Pd/Ir with 187Os/188Os ratios and good correlations of modal amounts of silicates, especially garnet, with Os isotope ratios. These correlations suggest that the Highly Siderophile Elements (HSE) and incompatible element reenrichment and modal metasomatism result from one single major metasomatic event at late Archean. Our detailed study of Finsch peridotites highlights the importance of using multiple isotopic systems, to constrain the ages of events defining the evolution of lithospheric mantle. The Re-Os isotope system is very effective in documenting the presence of Archean lithosphere, but only the oldest TRD ages may accurately date or closely approach the age of the last major partial melting event. For a meaningful interpretation of the Re-Os isotope systematics the data must be combined with HSE patterns, trace-element compositions and ideally other isotopic systems, e.g. Lu-Hf. This is highlighted by the widespread evidence in Finsch peridotites of Pt, Pd and Re enrichment through significant Base Metal Sulfide (BMS) addition (mainly in the range of 0.002-0.08?wt%) that systematically shifts the mode of TRD model ages to younger ages.
DS201911-2512
2019
Gibson, S.A.Black, B.A., Gibson, S.A.Deep carbon and the life cycle of large igneous provinces.Elements, Vol. 15, pp. 319-324.Mantlecarbon

Abstract: Carbon is central to the formation and environmental impact of large igneous provinces (LIPs). These vast magmatic events occur over geologically short timescales and include voluminous flood basalts, along with silicic and low-volume alkaline magmas. Surface outgassing of CO2 from flood basalts may average up to 3,000 Mt per year during LIP emplacement and is subsidized by fractionating magmas deep in the crust. The large quantities of carbon mobilized in LIPs may be sourced from the convecting mantle, lithospheric mantle and crust. The relative significance of each potential carbon source is poorly known and probably varies between LIPs. Because LIPs draw on mantle reservoirs typically untapped during plate boundary magmatism, they are integral to Earth’s long-term carbon cycle.
DS202004-0515
2020
Gibson, S.A.Gibson, S.A., Rooks, E.E., Day, J.A., Petrone, C.M., Leat, P.T.The role of sub-continental mantle as both "sink" and "source" in deep Earth volatile cycles.Geochimica et Cosmochimica Acta, Vol. 275, pp. 140-162.Mantlecraton

Abstract: The extent to which Earth’s sub-continental lithospheric mantle modulates the flux of volatile elements from our planet’s deep interior to its atmosphere (via volcanism) is poorly constrained. Here, we focus on "off-craton" sub-continental lithospheric mantle because this long-lived reservoir potentially acts as both a volatile “sink” and “source” during major heating and rifting events. The sub-continental lithospheric mantle is primarily formed of peridotites with subordinate amounts of pyroxenites. While both lithologies are dominated by nominally-volatile-free mantle minerals, some of these phases have been shown to contain non-negligible amounts of H2O (e.g. 100’s of ppmw in clinopyroxene). Data for volatile elements other than Li are, however, limited. We present new, high-precision, in-situ Secondary Ion Mass Spectrometry analyses of H, F, Cl, Li and B in olivine and pyroxenes from well-characterised garnet- and spinel-bearing peridotites and pyroxenites (from southern Patagonia and the Antarctic Peninsula). Our study confirms that clinopyroxene is the main host of H2O and F. The maximum F contents we report (up to 154 ppmw) are higher than those in previous studies and occur in Ti-Cr diopsides in highly-metasomatised peridotites and Ti-Al augites from clinopyroxenite veins. Water contents of clinopyroxenes (up to 615 ppmw) are within the range previously published for continental mantle. Lithium concentrations are low (<5 ppmw) in all analysed phases and both Cl and B are below detection levels (14 ppmw and 0.03 ppmw, respectively). Unique to our study is the large variation in major- and trace-element concentrations of the clinopyroxenes, which allows us to place quantitative constraints on how volatiles are stored in the mantle. We demonstrate that: (i) F contents of clinopyroxenes closely correlate with Ti and (ii) and is systematic and inversely correlated with temperature. Despite the redistribution of volatiles during sub-solidus re-equilibration, we show that the first order control on the concentration of volatiles in clinopyroxene is the style of metasomatism, i.e. channellised flow versus reactive percolation. The mean bulk volatile contents of peridotites from Pali Aike and the Antarctic Peninsula (H2O?=?89?±?31 ppmw, F?=?16?±?11.2 ppmw and Li?=?2?±?0.7 ppmw) are within the range previously published for continental "off-craton" mantle. The pyroxenites have significantly higher mean bulk concentrations of H2O (260?±?59 ppmw), F (86?±?43 ppmw) and Li (1.0?±?0.35 ppmw). While the greater capacity of mantle pyroxenites to host H2O relative to the associated peridotites has previously been observed in global "off-craton" mantle xenolith suites (e.g. Oahu, Hawaii; eastern China and the Rio Grande Rift, SW USA), here we show for the first time that pyroxenites are also major hosts of F (but not Cl, Li or B). Because of their relatively low solidus temperatures, pyroxenites in "off-craton" settings will be readily re-mobilised during lithospheric extension (and heating). We suggest these pyroxene-rich mantle lithologies may be responsible for the elevated concentrations of H2O and F observed in basalts and volcanic gasses from major continental rift zones and flood basalt provinces, and hence an important consideration in models of global volatile cycles.
DS1860-0938
1896
Gibson, W.Gibson, W.The Geology of Africa in Relation to Its Mineral WealthInstitute Mining Engineering NEWCASTLE Transactions, Vol. 12, PP. 303-320.Africa, South AfricaDiamonds, Economics
DS1970-0820
1973
Gibson, W.M.Sellschop, J.P.F., Gibson, W.M.Studies of Ion Channeling and Surface Impurities in DiamondDiamond Research, VOLUME FOR 1973, PP. 32-39.GlobalDiamond Genesis
DS201112-1026
2011
GicquelTallaire, A., Barjon, J., Brinza, O., Achard, Silva, Mille, Issaoui, Tardieu, GicquelDislocations and impurities introduced from etch-pitts at the epitaxial growth resumption of diamond.Diamond and Related Materials, Vol. 20, 7, pp. 875-881.TechnologyDiamond morphology
DS200612-1508
2005
Gicquel, A.Wang, W., Tallaire, A., Hall, M.S., Moses, T.M., Achard, J., Sussmans, R.S., Gicquel, A.Experimental CVD synthetic diamonds form LIMPH-CNRD France.Gems & Gemology, Vol. 41, 3, Fall, pp. 234244.TechnologySynthetic diamonds
DS1970-0086
1970
Giddey, R.F.Giddey, R.F.Metallogenic Provinces in Southern AfricaPetros, Vol. 2, PP. 26-36.South AfricaMetallogeny, Genesis, Kimberlite
DS1995-0837
1995
Giddings, J.W.Idnurm, M., Giddings, J.W.Paleoproterozoic-Neoproterozoic North America-Australia link: new evidence from PaleomagnetismGeology, Vol. 23, No. 2, Feb. pp. 149-152Australia, North AmericaPaleomagnetism, Proterozoic
DS2000-1023
2000
Giddings, J.W.Wingate, M.T.D., Giddings, J.W.Age and paleomagnetism of the Mundine Well dyke swarm: implications for Australia-Laurentia connection 755 MaPrecambrian Research, Vol. 100, No. 1-3, pp. 335-57.AustraliaDyke swarm, Geophysics - paleomagnetics
DS201707-1326
2017
Giebel, R.J.Giebel, R.J., Gauert, C.D.K., Marks, M.A.W., Costin, G., Markl, G.Multi stage formation of REE minerals in the Palabora carbonatite complex, South Africa.American Mineralogist, Vol. 102, pp. 1218-1233.Africa, South Africacarbonatite - Palabora

Abstract: The 2060 Ma old Palabora Carbonatite Complex (PCC), South Africa, comprises diverse REE mineral assemblages formed during different stages and reflects an outstanding instance to understand the evolution of a carbonatite-related REE mineralization from orthomagmatic to late-magmatic stages and their secondary post-magmatic overprint. The 10 rare earth element minerals monazite, REE-F-carbonates (bastnäsite, parisite, synchysite), ancylite, britholite, cordylite, fergusonite, REE-Ti-betafite, and anzaite are texturally described and related to the evolutionary stages of the PCC. The identification of the latter five REE minerals during this study represents their first described occurrences in the PCC as well as in a carbonatite complex in South Africa. The variable REE mineral assemblages reflect a multi-stage origin: (1) fergusonite and REE-Ti-betafite occur as inclusions in primary magnetite. Bastnäsite is enclosed in primary calcite and dolomite. These three REE minerals are interpreted as orthomagmatic crystallization products. (2) The most common REE minerals are monazite replacing primary apatite, and britholite texturally related to the serpentinization of forsterite or the replacement of forsterite by chondrodite. Textural relationships suggest that these two REE-minerals precipitated from internally derived late-magmatic to hydrothermal fluids. Their presence seems to be locally controlled by favorable chemical conditions (e.g., presence of precursor minerals that contributed the necessary anions and/or cations for their formation). (3) Late-stage (post-magmatic) REE minerals include ancylite and cordylite replacing primary magmatic REE-Sr-carbonates, anzaite associated with the dissolution of ilmenite, and secondary REE-F-carbonates. The formation of these post-magmatic REE minerals depends on the local availability of a fluid, whose composition is at least partly controlled by the dissolution of primary minerals (e.g., REE-fluorocarbonates). This multi-stage REE mineralization reflects the interplay of magmatic differentiation, destabilization of early magmatic minerals during subsequent evolutionary stages of the carbonatitic system, and late-stage fluid-induced remobilization and re-/precipitation of precursor REE minerals. Based on our findings, the Palabora Carbonatite Complex experienced at least two successive stages of intense fluid–rock interaction.
DS201709-1988
2017
Giebel, R.J.Giebel, R.J., et al.Fluid mineral interaction and REE mineralization in the Palabora carbonatite complex.Goldschmidt Conference, abstract 1p.Africa, South Africacarbonatite, Palabora

Abstract: The Palabora Carbonatite Complex (PCC) in South Africa intruded at 2060 Ma into Archean basement. The tripartite pipe-like intrusion is represented by a northern and southern pyroxenite and the central Loolekop pipe. Carbonatites and phoscorites of the Loolekop pipe experienced at least 4 stages of mineralization, recrystallization and redistibution reflected by an (1) orthomagmatic, (2) late-magmatic, (3) sulphide and (4) post-magmatic phase (Giebel et al., 2017). These four stages exhibit considerable variability of REE mineralization and especially stages 2 and 4 show intense fluid-rock interaction textures. We present microtextural and compositional data on apatite and phlogopite along a 2 km depth profile through the Loolekop pipe and investigate how these data reflect fluidmineral interaction with depth during stage (2). A special focus lies on understanding the behaviour, sources and sinks of REE elements. While fluid-apatite interaction causes a dissolution of apatite coupled with a precipitation of monazite at apatite rims, the fluid-phlogopite interaction induces a chloritization of phlogopite and an occasional formation of britholite along strongly dissolved phlogopite rims. We suspect that REE are transported into the system by this late-magmatic fluid rather than being released by the dissolution of orthomagmatic REE-bearing minerals. Combining these observations with fluid inclusion textures and microthermometry, we will investigate the nature and composition of the involved fluids and will try to model REE mineralisation processes during late-magmatic fluidmineral ineraction
DS201812-2810
2019
Giebel, R.J.Giebel, R.J., Marks, M.A.W., Gauert, C.D.K., Markl, G.A model for the formation of carbonatite-phoscorite assemblages based on the compositional variations of mica and apatite from the Palabora carbonatite complex, South Africa.Lithos, Vol. 324-325, pp. 89-104.Africa, South Africadeposit - Palabora

Abstract: A detailed electron microprobe study has been carried out on the compositional variations of mica and apatite from carbonatites, phoscorites and associated pyroxenites (and fenites) of the Loolekop deposit, Palabora Carbonatite Complex (South Africa). Mica in pyroxenites and fenites is Mg-rich biotite, whilst micas in carbonatites and phoscorites are compositionally diverse including phlogopite, Ba-rich phlogopite (up to 30% kinoshitalite component), IVAl-rich phlogopite (up to 30% eastonite component) and tetraferriphlogopite. The various types of phlogopites are interpreted as orthomagmatic phases, whereas tetraferriphlogopite precipitation was a late-magmatic to hydrothermal process that additionally introduced REE into the system. Orthomagmatic apatite is generally REE- and Sr-poor fluorapatite and does not show large compositional differences between rock types. Apatite associated with the late-stage tetraferriphlogopite mineralization reaches higher levels of REE (up to 4.9?wt%), Si (up to 1.5?wt% SiO2), Sr (up to 2.6?wt% SrO) and Na (up to 1.0?wt% Na2O). The compositional variation of micas and apatites, which is affiliated with distinct rock types, reflects the multi-stage evolution of the Loolekop deposit and provides detailed insight into the relationships of the carbonatite-phoscorite assemblage. The obtained data support the separation of phoscorite and carbonatite by immiscibility from a common parental magma, which may happen due to a decrease of temperature and/or pressure during the ascent of the magma. This results in a density contrast between the carbonatitic and phoscoritic components that will lead to descending phoscorite accumulations at the outer zones of the magma channel and a jet-like ascent (further promoted by its extremely low viscosity) of the carbonatite magma. The genetic model deduced here explains the peculiar association of carbonatites, phoscorites and silicate rocks in many alkaline complexes worldwide.
DS201902-0273
2019
Giebel, R.J.Giebel, R.J., Marks, M.A.W., Gauert, C.K., Markl, G.A model for the formation of carbonatite-phoscorite assemblages based on the compositonal variations of mica and apatite from the Palabora carbonatite complex, South AfricaLithos, Vol. 324, pp. 68-73.Europe, Azoresdeposit - Palabora

Abstract: A detailed electron microprobe study has been carried out on the compositional variations of mica and apatite from carbonatites, phoscorites and associated pyroxenites (and fenites) of the Loolekop deposit, Palabora Carbonatite Complex (South Africa). Mica in pyroxenites and fenites is Mg-rich biotite, whilst micas in carbonatites and phoscorites are compositionally diverse including phlogopite, Ba-rich phlogopite (up to 30% kinoshitalite component), IVAl-rich phlogopite (up to 30% eastonite component) and tetraferriphlogopite. The various types of phlogopites are interpreted as orthomagmatic phases, whereas tetraferriphlogopite precipitation was a late-magmatic to hydrothermal process that additionally introduced REE into the system. Orthomagmatic apatite is generally REE- and Sr-poor fluorapatite and does not show large compositional differences between rock types. Apatite associated with the late-stage tetraferriphlogopite mineralization reaches higher levels of REE (up to 4.9?wt%), Si (up to 1.5?wt% SiO2), Sr (up to 2.6?wt% SrO) and Na (up to 1.0?wt% Na2O). The compositional variation of micas and apatites, which is affiliated with distinct rock types, reflects the multi-stage evolution of the Loolekop deposit and provides detailed insight into the relationships of the carbonatite-phoscorite assemblage. The obtained data support the separation of phoscorite and carbonatite by immiscibility from a common parental magma, which may happen due to a decrease of temperature and/or pressure during the ascent of the magma. This results in a density contrast between the carbonatitic and phoscoritic components that will lead to descending phoscorite accumulations at the outer zones of the magma channel and a jet-like ascent (further promoted by its extremely low viscosity) of the carbonatite magma. The genetic model deduced here explains the peculiar association of carbonatites, phoscorites and silicate rocks in many alkaline complexes worldwide.
DS201909-2041
2019
Giebel, R.J.Giebel, R.J., Marks, M.A.W., Gauert, C.D.K., Markl, G.A model for the formation of carbonatite-phoscorite assemblages.Goldschmidt2019, 1p. AbstractGlobalcarbonatite

Abstract: A detailed electron microprobe study has been carried out on the compositional variations of mica and apatite from carbonatites, phoscorites and associated pyroxenites (and fenites) of the Loolekop deposit, Palabora Carbonatite Complex (South Africa). Mica in pyroxenites and fenites is Mg-rich biotite, whilst micas in carbonatites and phoscorites are compositionally diverse including phlogopite, Ba-rich phlogopite (up to 30% kinoshitalite component), IVAl-rich phlogopite (up to 30% eastonite component) and tetraferriphlogopite. The various types of phlogopites are interpreted as orthomagmatic phases, whereas tetraferriphlogopite precipitation was a late-magmatic to hydrothermal process that additionally introduced REE into the system. Orthomagmatic apatite is generally REE- and Sr-poor fluorapatite and does not show large compositional differences between rock types. Apatite associated with the late-stage tetraferriphlogopite mineralization reaches higher levels of REE (up to 4.9?wt%), Si (up to 1.5?wt% SiO2), Sr (up to 2.6?wt% SrO) and Na (up to 1.0?wt% Na2O). The compositional variation of micas and apatites, which is affiliated with distinct rock types, reflects the multi-stage evolution of the Loolekop deposit and provides detailed insight into the relationships of the carbonatite-phoscorite assemblage. The obtained data support the separation of phoscorite and carbonatite by immiscibility from a common parental magma, which may happen due to a decrease of temperature and/or pressure during the ascent of the magma. This results in a density contrast between the carbonatitic and phoscoritic components that will lead to descending phoscorite accumulations at the outer zones of the magma channel and a jet-like ascent (further promoted by its extremely low viscosity) of the carbonatite magma. The genetic model deduced here explains the peculiar association of carbonatites, phoscorites and silicate rocks in many alkaline complexes worldwide.
DS201909-2042
2019
Giebel, R.J.Giebel, R.J., Parsapoor, A., Walter, B.F., Braunger, S., Marks, M.A.W.Evidence for magma-wall rock interaction in carbonatites from the Kaiserstuhl volcanic complex ( southwest Germany).Journal of Petrology , Vol. 60, 6, pp. 1163-1194.Europe, Germanycarbonatite

Abstract: The mineralogy and mineral chemistry of the four major sövite bodies (Badberg, Degenmatt, Haselschacher Buck and Orberg), calcite foidolite/nosean syenite xenoliths (enclosed in the Badberg sövite only) and rare extrusive carbonatites of the Kaiserstuhl Volcanic Complex in Southern Germany provide evidence for contamination processes in the carbonatitic magma system of the Kaiserstuhl. Based on textures and composition, garnet and clinopyroxene in extrusive carbonatites represent xenocrysts entrained from the associated silicate rocks. In contrast, forsterite, monticellite and mica in sövites from Degenmatt, Haselschacher Buck and Orberg probably crystallized from the carbonatitic magma. Clinopyroxene and abundant mica crystallization in the Badberg sövite, however, was induced by the interaction between calcite foidolite xenoliths and the carbonatite melt. Apatite and micas in the various sövite bodies reveal clear compositional differences: apatite from Badberg is higher in REE, Si and Sr than apatite from the other sövite bodies. Mica from Badberg is biotite- and comparatively Fe2+-rich (Mg# = 72-88). Mica from the other sövites, however, is phlogopite (Mg# up to 97), as is typical of carbonatites in general. The typical enrichment of Ba due to the kinoshitalite substitution is observed in all sövites, although it is subordinate in the Badberg samples. Instead, Badberg biotites are strongly enriched in IVAl (eastonite substitution) which is less important in the other sövites. The compositional variations of apatite and mica within and between the different sövite bodies reflect the combined effects of fractional crystallization and carbonatite-wall rock interaction during emplacement. The latter process is especially important for the Badberg sövites, where metasomatic interaction released significant amounts of K, Fe, Ti, Al and Si from earlier crystallized nosean syenites. This resulted in a number of mineral reactions that transformed these rocks into calcite foidolites. Moreover, this triggered the crystallization of compositionally distinct mica and clinopyroxene crystals around the xenoliths and within the Badberg sövite itself. Thus, the presence and composition of clinopyroxene and mica in carbonatites may be useful indicators for contamination processes during their emplacement. Moreover, the local increase of silica activity during contamination enabled strong REE enrichment in apatite via a coupled substitution involving Si, which demonstrates the influence of contamination on REE mineralization in carbonatites.
DS201909-2061
2019
Giebel, R.J.Marks, M.A.W., Giebel, R.J., Walter, B.F., Braunger, S., Wenzel, T., Markl, G.Evidence for wall-rock assimilation in carbonatites from the Kaiserstuhl (German).Goldschmidt2019, 1p. AbstractEurope, Germanydeposit - Kaiserstuhl

Abstract: Contamination of carbonatites with crustal or cogenetic intrusive rocks is generally not considered to play an important role during carbonatite magmatism, because carbonatitic melts have low densities and viscosities, enabling them to rapidly ascend. Potential contamination by silicate rocks in carbonatites cannot easily be detected by means of radiogenic isotope data (such as Sr, Nd and Pb isotope data) as carbonatites often show high concentrations of these elements and their isotope systems are thereby “buffered” against contamination with silicate rocks. Textural, mineralogical and geochemical observations in carbonatites from the Kaiserstuhl (Germany) provide evidence for the interaction of carbonatitic magma with previously emplaced nosean syenites. This caused replacement of alkali feldspar by haüyne and recrystallization of garnet and clinopyroxene in the xenoliths, which released larger amounts of K, Al, Si and Fe. As a result, blackwall-like mica seams around the xenoliths formed and and compositionally distinct mica and clinopyroxene crystallized in the surrounding carbonatite. Moreover, the local increase of silica activity during contamination enabled strong REE enrichment in apatite via a coupled substitution involving Si, which demonstrates the potential influence of Si contamination on REE mineralization in carbonatites. We further suggest that the presence and composition of clinopyroxene and mica in carbonatites may be useful indicators for contamination processes during their emplacement. Mass-balance calculations based on experimental constraints for the solubility of Al and Si in carbonatitic magmas suggest that only minor amounts of mica can form from carbonatitic melt. Therefore, larger amounts of mica and mica-dominated lithologies (glimmerites) as observed in many carbonatite complexes suggest that some Si and Al in carbonatites may be sourced from surrounding host rocks. We hypothesize that assimilation and contamination processes in carbonatites may be the rule rather than an exception.
DS201909-2104
2019
Giebel, R.J.Walter, B.F., Steele-MacInnis, M., Giebel, R.J., Marks, M.A.W., Markl, G.Fluids exsolved from the Kaiserstuhl carbonatite, SW Germany: brine generation by boiling.Goldschmidt2019, 1p. AbstractEurope, Germanydeposit - Kaiserstuhl

Abstract: Studies on fluid inclusions in carbonatitic rocks are essential to understand the physicochemical processes involved in carbonatite-related hydrothermal ore mineralization. Although little is known about the composition of carbonatite-derived fluids. We investigated fluid inclusions in the Kaiserstuhl carbonatites, SW Germany [1,2] and identified four different types typically known from carbonatitic systems worldwide [3]: (I): Vapor-poor H2O-NaCl fluids with <50 wt.% salinity. (II): Vapor-rich H2O-NaCl-CO2 fluids with <5 wt.% salinity. (III): Multi-component fluids with high salinity and CO2. (IV): Multi-component fluids with high salinity, no CO2. Homogenization temperatures (156 to 530°C) of all fluid types generally show a wide range [this study, 2]. Primary type I fluid inclusions occur in early magmatic olivine/monticellite, as well as paragenetically later apatites and calcites [2]. This indicates a ubiquitous existence of a saline brine, which does not reach saturation with respect to halite, during early to late crystallization stages. Liquidus surface modelling based quantifications for fluid type III suggest that carbonatite melts predomonantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (type III or IV, respectively). Such fluid inclusions, with type III (CO2-free) on one side and type IV (and II, both CO2-rich) on the other side, may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, is probably triggered by a rapid pressure release during “pneumatic hammer-like,” discontinuous melt ascent.
DS202006-0955
2020
Giebel, R.J.Walter, B.F., Steele-MacInnis, M., Giebel, R.J., Marks, M.A.W., Markl, G.Complex carbonatite-sulfate brines in fluid inclusions from carbonatites: estimating compositions in the system H2O-Na-K-CO3-SO4-Cl. KaiserstuhlGeochimica et Cosmochimica Acta, Vol. 277, pp. 224-242. pdfEurope, Germanycarbonatite

Abstract: Studies of fluid inclusions in carbonatitic rocks are essential for understanding physicochemical processes involved in carbonatite-related hydrothermal ore mineralization and fenitization. However, the composition of many carbonatite-derived fluids is challenging to quantify, which hampers their detailed interpretation. Here, we present a systematic study of microthermometry of fluid inclusions found in carbonatites from the Kaiserstuhl (SW Germany), and a simple numerical model to estimate the compositions of such fluids, which are typical of numerous carbonatites worldwide. Four types of fluid inclusions have been identified in the Kaiserstuhl carbonatites: (I) vapor-poor H2O-NaCl fluids with <50?wt.% salinity; (II) vapor-rich H2O-NaCl-CO2 fluids with <5?wt.% salinity; (III) multi-component fluids with high salinity and high CO2 contents; and (IV) multi-component fluids with high salinity but little to no CO2. At present, it is only possible to quantify fluid compositions for types I and II. For the complex types III and IV, we conducted predictive modeling of the liquidus surface based on the Margules equations. The results suggest that carbonatite melts predominantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (types III or IV). Such fluid inclusions may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, was probably triggered by a rapid pressure release during melt ascent. The present model enables quantification of fluid compositions associated with carbonatitic magmatism.
DS202109-1494
2021
Giebel, R.J.Walter, B.F., Giebel, R.J., Steele-MacInnis, M., Marks, M.A., Kolb, J., Markl, G.Fluids associated with carbonatitic magmatism: a critical review and implications for carbonatite magma ascent.Earth Science Reviews , Vol. 215, 103509, 27p. PdfMantlemagmatism

Abstract: Carbonatites are formed from volatile-rich melts, commonly associated with a characteristic hydrothermal footprint. However, studies of their fluid inclusions are relatively scarce and heterogeneous in terms of detail and completeness of the data presented. Here, we review and discuss comprehensively the results of previous studies and derive a general model for the formation and properties of fluids associated with carbonatitic magmatism. Worldwide, four types of fluid inclusion occur in carbonatites: (type I/HS) vapour-poor H2O-NaCl fluids with up to 50 wt% salinity; (type II/HC) vapour-rich H2O-NaCl-CO2 fluids with <5 wt% salinity; (type III/DS) multi-component fluids with high salinity and without CO2; and (type IV/CDS) multi-component fluids with high salinity and high CO2. This global dataset suggests continuous fluid release from deep to shallow-level intrusions. Modelling of the liquidus surface indicates that carbonatite magmas generally exsolve a saline brine (type I/HS). This brine separates/evolves into a Na-K-sulfate-carbonate/bicarbonate-chloride brine with or without CO2 (types III/DS and IV/CDS), trapped together with low salinity CO2-rich fluids produced by immiscibility. Fluid immiscibility is related to rapid pressure release during fast, forceful and discontinuous magma ascent, which we envisage as a "pneumatic jackhammer" model for carbonatite ascent and emplacement. In this model, cyclic and progressive fluid flux via pressure build-up and subsequent catastrophic pressure release results in a self-sustaining crustal ascent of the buoyant, low-viscosity magma. This process allows for rapid and efficient magma ascent, in particular above the brittle-ductile transition zone, where pressures that prevailed during apatite crystallization have been estimated in numerous complexes. Moreover, this model provides an explanation for the apparent absence of shallow carbonatite magma chambers (in a classical sense) and identifies fenitization as a phenomenon induced by both fluids released during magma ascent and residual fluids.
DS1997-0401
1997
Giebovtsky, V.A.Giebovtsky, V.A.The Early Precambrian of Russia #1Gordon and Breach Publ, 979p. approx. $ 100 United StatesRussiaBook - ad, Precambrian
DS201112-0369
2011
Giehl, C.Giehl, C., Bellucci, P., Nguyen, H-T., Marks, M., Nowak, M.Experimental investigation of the differentiation of iron rich peralkaline magma.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologyMagmatism
DS202007-1184
2020
Gielbel, R.J.Walter, B.F., Steele-MacInnis, M., Gielbel, R.J., Marks, M.A.W., Markl, G.Complex carbonatite-sulfate brines in fluid inclusions from carbonatites: estimating compositions in the system H2O-Na-K-CO3-SO4-ClGeochimica et Cosmochimica Acta, Vol. 277, pp. 224-242. pdfEurope, Germanydeposit - Kaiserstuhl

Abstract: Studies of fluid inclusions in carbonatitic rocks are essential for understanding physicochemical processes involved in carbonatite-related hydrothermal ore mineralization and fenitization. However, the composition of many carbonatite-derived fluids is challenging to quantify, which hampers their detailed interpretation. Here, we present a systematic study of microthermometry of fluid inclusions found in carbonatites from the Kaiserstuhl (SW Germany), and a simple numerical model to estimate the compositions of such fluids, which are typical of numerous carbonatites worldwide. Four types of fluid inclusions have been identified in the Kaiserstuhl carbonatites: (I) vapor-poor H2O-NaCl fluids with <50?wt.% salinity; (II) vapor-rich H2O-NaCl-CO2 fluids with <5?wt.% salinity; (III) multi-component fluids with high salinity and high CO2 contents; and (IV) multi-component fluids with high salinity but little to no CO2. At present, it is only possible to quantify fluid compositions for types I and II. For the complex types III and IV, we conducted predictive modeling of the liquidus surface based on the Margules equations. The results suggest that carbonatite melts predominantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (types III or IV). Such fluid inclusions may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, was probably triggered by a rapid pressure release during melt ascent. The present model enables quantification of fluid compositions associated with carbonatitic magmatism.
DS200412-0514
2004
Gierlotka, S.Ekimov, E.A., Sidorov, V.A., Melnik, N.N., Gierlotka, S., Presz, A.Synthesis of polycrystalline diamond in the boron carbide graphite and boron graphite systems under high pressure and temperaturJournal of Materials Research, Vol. 39, 15, pp. 4957-4960.TechnologyDiamond synthesis
DS1986-0288
1986
Gierth, E.Gierth, E., Goldman, D., Leonardos, O.H., Baecker, M.L.Main features of the paragenetic evolution of the Carbonatite complex of Catalao 1, GoiasBrasilIn: Symposium on Latin American Sciences, Vol. 1985 No. 9-10, pp. 1469-1475BrazilBlank
DS1989-0510
1989
Gierth, E.Gierth, E., Leonardos, O.H.Some characteristics of the niobium ores in the unweathered sections Of the carbonatite complexes Catalao I and II, Goias, Brasil79th. Annual Meeting Of The Geologische Vereinigung, Mineral, p. 1-2. (abstract.)BrazilCarbonatite
DS200812-0409
2008
Gies, J.Gies, J., Schreurs, G., Berger, A., Herweigh, M., Gnos, E.Indenter tectonics in central Madagascar.Geotectonic Research, Vol. 95, suppl. 1 pp. 51-53.Africa, MadagascarTectonics
DS2001-1285
2001
Giese, et al.Yliniemi, J., Tiira, T., Luosto, Komminaho, Giese, et al.EUROBRIDGE'95: deep seismic profiling within the East European CratonTectonophysics, Vol. 339, No. 1-2, pp. 153-75.EuropeGeophysics - seismics, Craton
DS1997-0871
1997
Giese, P.Okaya, N., Tawackoli, S., Giese, P.Area -balanced model of the late Cenozoic tectonic evolution of the central Andean arc and back arcGeology, Vol. 25, No. 4, April pp. 367-370Chile, BoliviaTectonics model, Volcanics
DS2002-0896
2002
Giese, R.Kozlovskaya, E., taran, L.N., Yliniemi, J., Giese, R., Karatayev, G.I.Deep structure of the crust along the Fennoscandia Sarmatia Junction Zone ( CentralTectonophysics, Vol. 358,1-4,pp. 97-120.Fennoscandia, Europe, UralsTectonics
DS1993-0542
1993
Giesecke, A.Giesecke, A.Carbonatites and kimberlites; keys for fissiogeneses, expensionism andgeodynamics. (in German)Mitt. Geologisch-Paleo. Hamburg, (in German), Vol. 69, pp. 229-250.GlobalAlkaline rocks, Kimberlites
DS1995-2108
1995
Gieskes, J.M.You, C.F., Spivack, A.J., Gieskes, J.M., RosenbauerExperimental study of boron geochemistry: implications for fluid processes in subduction zonesGeochimica et Cosmochimica Acta, Vol. 59, No. 12, pp. 2435-2442GlobalGeochemistry - experimental, Boron
DS2002-1252
2002
Giester, G.Petersen, O.V., Giester, G., Brandstatter, NiedermayrNabesite, new mineral species from Ilmaussaq alkaline complex, south GreenlandCanadian Mineralogist, Vol.40,1,Feb.pp. 173-81.GreenlandAlkaline rocks
DS201609-1729
2016
Giester, G.Lykova, I.S., Pekov, I.V., Chukanov, N.V., Belakovskiy, D.I., Yapaskurt, V.O., Zubkova, N.V., Britvin, S.N., Giester, G.Calciomurmanite a new mineral from the Lovozero and Khibiny alkaline complexes, Kola Peninsula.European Journal of Minerlogy, in press avaialbe 15p.RussiaMineralogy
DS200412-0662
2004
Giesting, P.A.Giesting, P.A., Hofmeister, A.M., Wopenka, B., Gwanmesia, G.D., Joliff, B.L.Thermal conductivity and thermodynamics of majoritic garnets: implications for the transition zone.Earth and Planetary Science Letters, Vol. 218, 1-2, Jan. 30, pp. 45-56.MantleGeothermometry, heat capacity, entropy
DS200612-0350
2006
Giffin, B.J.Downes, P.J., Wartho, J-A., Giffin, B.J.Magmatic evolution and ascent history of the Aries micaceous kimberlite, central Kimberley Basin, Western Australia: evidence from zoned phlogopite phenocrysts and UV laserJournal of Petrology, Vol. 47, 9, Sept. pp. 1751-1783.Australia, Western AustraliaGeochronology - UV laser, analysis phlogopite-biotite
DS1960-0146
1961
Gifford, A.C.Gifford, A.C.The Geology of Eastern Marangudzi, Southern RhodesiaLondon: Ph.d. Thesis, University London., 171P.ZimbabweRegional Studies
DS1960-0847
1967
Gifford, A.C.Jones, D.L., Walford, M.E.R., Gifford, A.C.A Paleomagnetic Result from the Ventersdorp Lavas of South Africa.Earth and Planetary Science Letters, Vol. 2, No. 3, PP. 155-158.South AfricaDe Beers Mine, Paleomagnetics
DS201012-0490
2010
Gifford, J.Meert, J.G., Pandit, M.K., Pradhan, V.R., Banks, J., Sirianni, R., Stroud, M., Newstead, B., Gifford, J.Precambrian crustal evolution of Peninsular India: a 3.0 billion year odyssey.Journal of Asian Earth Sciences, Vol. 39, 6, pp. 483-515.IndiaGeodynamics, tectonics
DS201412-0291
2014
Gifford, J.N.Gifford, J.N., Mueller, P.A., Foster, D.A., Mogk, D.W.Precambrian crustal evolution in the Great Falls Tectonic Zone: insights from xenoliths from the Montana alkali province.Journal of Geology, Vol. 122, 5, pp. 531-548.United States, MontanaAlkalic
DS201502-0057
2014
Gifford, J.N.Gifford, J.N., Mueller, P.A., Foster, D.A, Mogk, D.W.Precambrian crustal evolution in the Great Falls Tectonic Zone: insights from xenoliths from the Montana Alkali province.Journal of Geology, Vol. 122, Sept. pp. 531-548.United States, MontanaAlkalic
DS201809-2027
2018
Gifford, J.N.Gifford, J.N., Mueller, P.A., Foster, D.A., Mogk, D.W.Extending the realm of Archean crust in the Great Falls tectonic zone: evidence from the Little Rocky Mountains, Montana.Precambrian Research, Vol. 315, pp. 264-281.United States, Montanacraton

Abstract: Two prominent features separate the Archean Wyoming and Hearne cratons: the Paleoproterozoic Great Falls tectonic zone (GFTZ) and the Medicine Hat block (MHB), neither of which is well defined spatially because of Phanerozoic sedimentary cover. Based on limited data, the MHB is thought to be a structurally complex mix of Archean (2.6-3.1?Ga) and Proterozoic (1.75?Ga) crust, but is recognized primarily by its geophysical signature, and its influence on the geochemistry of younger igneous rocks. Similarly, the GFTZ was recognized on the basis of broad differences in geophysical patterns, isopachs of Paleozoic sedimentary sections, and lineaments; however, juvenile arc rocks in the Little Belt Mountains (LBM) and strongly overprinted Archean rocks in southwestern Montana show it to be a dominantly Paleoproterozoic feature. The Little Rocky Mountains (LRM) of Montana provide access to exposures of the northeastern-most Precambrian crust in the MHB-GFTZ region. U/Pb ages of zircons from Precambrian rocks of the LRM range from 2.4 to 3.3?Ga, with most ages between 2.6 and 2.8?Ga. Whole-rock analyses yield Sm-Nd TDM from 3.1 to 4.0?Ga and initial ?Nd(T) values calculated at U-Pb zircon crystallization ages range from ?0.9 to ?10.5, indicating significant contributions from older Archean crust. The high proportion of 2.6-2.8?Ga U/Pb ages differentiates LRM crust from arc-related Paleoproterozoic magmatic rocks exposed in the LBM to the southwest. The age and isotopic composition of the LRM gneisses are similar to crust in the northern Wyoming Province (2.8-2.9?Ga), but Paleoproterozoic K-Ar cooling ages suggest crust in the LRM experienced the Paleoproterozoic metamorphism and deformation that characterizes the GFTZ. Consequently, its history differs markedly from the adjacent Beartooth-Bighorn magmatic zone of the northern Wyoming Province, which does not record Paleoproterozoic tectonism, but has a strong correlation with the Montana metasedimentary terrane that was strongly overprinted during the Paleoproterozoic Great Falls orogeny that defines the GFTZ. The LRM, therefore, likely provides a unique, and perhaps the only, opportunity to characterize Archean crust of the MHB.
DS201811-2562
2018
Gifford, J.N.Craddock, J., Malone, D., Schmitz, M.D., Gifford, J.N.Strain variations across the Proterozoic Penokean Orogen, USA and Canada. Sudbury impact Precambrian Research, Vol. 318, pp. 25-69.United States, Canadaorogeny

Abstract: Strata in the Huron (2.5-2.0 Ga) and Animikie (2.2-1.85 Ga) basins were deposited on the southern margin of the Archean Superior province. These rocks were deformed during the Penokean orogeny (?1850 Ma) followed by subsequent accretionary orogens to the south at 1750 Ma (Yavapai) and 1630 Ma (Mazatzal). Strain patterns are unique to each orogenic belt with no far-field effect: Archean Wawa terrane rocks in the Penokean foreland preserve deformation associated with Archean accretion with no younger Penokean, Yavapai or Mazatzal strain overprint. The Penokean orogeny deformed Huron-Animikie basin sediments into a north-vergent fold-and-thrust belt with no Yavapai or Mazatzal strain overprint. Yavapai orogen strains (SW-NE margin-parallel shortening) are unique when compared to the younger Mazatzal shortening (N20°W) shortening, with no strain overprint. Penokean deformation is characterized by shortening from the south including uplifted Archean gneisses and a northerly thin-skinned fold-and-thrust belt, with north-vergent nappes and a gently-dipping foreland. Our study of finite and calcite twinning strains (n=60) along (?1500 km) and across (?200 km) the Penokean belt indicate that this orogeny was collisional as layer-parallel shortening axes are parallel across the belt, or parallel to the tectonic transport direction (?N-S). Penokean nappe burial near the margin resulted in vertical shortening strain overprints, some of which are layer-normal. The Sudbury impact layer (1850 Ma) is found across the Animikie basin and provides a widespread deformation marker with many local, unique strain observations. We also report new geochronology (U-Pb zircon and apatite) for the gneiss-mafic dike rocks at Wissota (Chippewa Falls, WI) and Arbutus (Black River Falls, WI) dams, respectively, which bears on Penokean-Yavapai deformation in the Archean Marshfield terrane which was accreted during the Penokean orogen. Pseudotachylite formation was common in the Superior province Archean basement rocks, especially along terrane boundaries reactivated by contemporaneous Penokean, Trans-Hudson, Cape Smith and New Quebec deformation. In the hinterland (south), the younger Yavapai orogen (1750 Ma; n=8) deformation is preserved as margin-parallel horizontal shortening (?SW-NE) in Yavapai crust and up to 200 km to the north in the Penokean thrust belt as a strain and Barrovian metamorphic overprint. Mazatzal deformation (1630 Ma; n=16) is preserved in quartzites on Yavapai and Penokean crust with layer-parallel and layer-normal shortening strains oriented N20°W.
DS201804-0693
2018
Gifillan, S.M.V.Gifillan, S.M.V., Ballentine, C.J.He, Ne and Ar 'snapshot' of the subcontinental lithospheric mantle from CO2 well gas.Chemical Geology, Vol. 480, pp. 116-127.Mantlechemistry

Abstract: The subcontinental lithospheric mantle (SCLM) constitutes a significant portion of the upper mantle sourcing magmatic volatiles to the continents above, yet its geochemical signature and evolution remain poorly constrained. Here we present new interpretation of noble gas datasets from two magmatic CO2 fields in the SW US, namely Bravo Dome and Sheep Mountain, which provide a unique insight into the volatile character of the SCLM sourcing the Cenozoic volcanism in the region. We identify that reduction of 3He/4Hemantle ratio within the Sheep Mountain CO2 field can be attributed to radiogenic production within the SCLM. Using a Reduced Chi-Squared minimisation on the variation of derived 4He/21Necrust ratios within samples from the Sheep Mountain field, combined with a radiogenically raised 21Ne/22Nemantle end member, we resolve 3He/4Hemantle ratios of 2.59 ± 0.15 to 3.00 ± 0.18 Ra. These values correspond with a 21Ne/22Nemantle value of 0.136. Using these 3He/4Hemantle end member values with 21Nemantle resolved from Ne three component analysis, we derive the elemental 3He/22Nemantle of 2.80 ± 0.16 and radiogenic 4He/21Ne*mantle range of 1.11 ± 0.11 to 1.30 ± 0.14. A second Reduced Chi-Squared minimisation performed on the variation of 21Ne/40Arcrust ratios has allowed us to also determine both the 4He/40Armantle range of 0.78 to 1.21 and 21Ne/40Armantle of 7.66 ± 1.62 to 7.70 ± 1.54 within the field. Combining these ratios with the known mantle production ranges for 4He/21Ne and 4He/40Ar allows resolution of the radiogenic He/Ne and He/Ar ratios corresponding to the radiogenically lowered 3He/4Hemantle ratios. Comparing these values with those resolved from the Bravo Dome field allows identification of a clear and coherent depletion of He to Ne and He to Ar in both datasets. This depletion can only be explained by partial degassing of small melt fractions of asthenospheric melts that have been emplaced into the SCLM. This is the first time that it has been possible to resolve and account for both the mantle He/Ne and He/Ar ratios within a SCLM source. The data additionally rule out the involvement of a plume component in the mantle source of the two gas fields and hence any plume influence on the Colorado Plateau Uplift event.
DS1985-0233
1985
Gifitullina, D.S.Gifitullina, D.S., Solodova, Y.P., Khaydarov, A.A.Impurities in Diamonds of Fibrous Structure.*rusDoklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 284, No. 6, pp. 1464-1466RussiaCrystallography, Diamond Morphology
DS1993-0386
1993
Gigante, M.A.Earnshow, R.A., Gigante, M.A., Jones, H.Virtual reality systemsAcademic Press, 327p. approx. $ 50.00GlobalBook -ad, Virtual reality systems
DS1992-0566
1992
Giggenbach, W.F.Giggenbach, W.F.Isotopic shifts in waters from geothermal and volcanic systems along convergent plate boundaries and their originEarth and Planetary Science Letters, Vol. 113, No. 4, November pp. 495-510GlobalGeothermal systems, Plate tectonics
DS200812-0786
2008
GiglerNasdala, L., Gigler, Wildner, Grambole, Zaitsev, Harris, Hofmeister, Milledge, SatitkuneAlpha radiation damage in diamond.Goldschmidt Conference 2008, Abstract p.A672.TechnologyDiamond morphology
DS201312-0637
2013
Gigler, A.M.Nasdala, L., Grambole, D., Wildner, M., Gigler, A.M., Hainschwang, T., Zaitsev, A.M., Harris, J.W., Milledge, J., Schulze, D.J., Hofmeister, W., Balmer, W.A.Radio-colouration of diamond: a spectroscopic study.Contributions to Mineralogy and Petrology, Vol. 165, pp. 843-861.Africa, South Africa, Democratic Republic of Congo, South America, Brazil, VenezuelaDiamond - colour
DS1992-0243
1992
Giglierano, J.Chen, Xingzhi, Giglierano, J.The extraction of structural lineaments using Land sat multispectral imagery and geophysical dat a for northeast IowaGeological Society of America (GSA) Abstract Volume, Vol. 24, No. 4, April p. 9. abstract onlyIowaGeophysics, Lineaments
DS200612-0458
2006
Gignac, C.Gignac, C.Trends and outlook for mining equities.Insight Mining Business and Investment Forum, Held June 5-6, Toronto, 28p. Xerox of slides onlyGlobalEconomics - not specific to diamonds
DS1997-0402
1997
Giguere, E.Giguere, E., Hebert, R., Sharma, K.N.M., Cimon, J.Les peridotites grenvilliennes de l'Ouest du Quebec et leur potentiel diamantifere.Quebec Department of Mines, DV 97-03, p. 39.QuebecExploration - assessment
DS1998-0507
1998
Giguere, E.Giguere, E., Hebert, R., Sharma, K.N.M., Cimon, J.Les roches ultramafiques de la region de Temiscamingue et Fort CoulongeQuebec Department of Mines, DV 98-05, p. 41.QuebecExploration - assessment
DS2002-0568
2002
Giguere, E.Giguere, E., Corriveau, L., Beaudoin, G.Occurrence of ultramafic massifs in the western Grenville: petrogenesis and potential for diamond expl.Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.39, p.39QuebecTemiscaming, Bryson intrusions
DS2002-0569
2002
Giguere, E.Giguere, E., Corriveau, L., Beaudoin, G.Occurrence of ultramafic massifs in the western Grenville: petrogenesis and potential for diamond expl.Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.39, p.39QuebecTemiscaming, Bryson intrusions
DS201912-2790
2019
Giguet-Covex, C.Jacq, K., Giguet-Covex, C., Sabatier, P., Perrette, Y., Fanget, B., Coquin, D., Debret, M., Arnaud, F.High resolution grain size distribution of sediment core with hyperspectral imaging. ( not specific to diamond)Sedimentary Geology, Vol. 393-394, pdfGlobalhyperspectral

Abstract: The study of sediment cores allows for the reconstruction of past climate and environment through physical-chemical analysis. Nevertheless, this interpretation suffers from many drawbacks that can be overcome with the newest technologies. Hyperspectral imaging is one of these and allows a fast, high resolution, and non-destructive analysis of sediment cores. In this study, we use visible and near-infrared hyperspectral imaging to predict particle size fractions and distribution (PSD) at a resolution of 200??m on a previously well-studied sediment core taken from Lake Bourget (Western Alps, France). These predictions agree with previous studies on this core. Then, the PSD was used to estimate sedimentary deposit sources using the PSD unmixing algorithm AnalySize. It permitted estimation of the contribution of five sources (micrite, small and large bio-induced calcite crystals, diatom frustules, detrital particles), which had previously been characterized. The spatial dimension allowed for laminae to be discretized and counted, in agreement with the age-depth model previously established. We then evaluated the particle size and spectral signatures of each of these annual laminae, hence characterizing their physico-chemical composition. These high-resolution data also allowed for estimation of the accumulation rate (cm/year) of each of the main sources in the laminated unit and inferring the trophic status and the presence of instantaneous events of the lake.
DS1983-0494
1983
Gik, L.D.Orlov, YU.A., Gik, L.D., Bobrov, B.A., Kolobova, S.E.Modelling of the Effect of a Kimberlite Pipe on a Seismic Wave Field.Soviet Geology And Geophysics, Vol. 24, No. 3, PP. 88-94.RussiaKimberlite, Geophysics
DS202203-0349
2022
Gil, G.Grabarczyk, A., Gil, G., Liu, Y., Kotowski, J., Jokubauskas, P., Barnes, J.D., Nejbert, K., Wisniewska, J., Baginski, B.Ultramafic-alkaline-carbonatite Tajno intrusion in NE Poland: a new hypothesis.Ore Geology Reviews, doi.org/10.1016/j.oregeorev.2022.104772 Europe, Polandcarbonatite

Abstract: This manuscript presents results of the newest petrographic, mineralogical and bulk chemical, as well as H, C and O stable isotope study of carbonatites and associated silicate rocks from the Tajno Massif (NE Poland). The Tajno Intrusion is a Tournaisian-Visean ultramafic-alkaline-carbonatite body emplaced within the Paleoproterozoic rocks of the East European Craton (EEC). Carbonatites of the Tajno Massif can be subdivided into the calciocarbonatite (calcite), ferrocarbonatite (ankerite), and breccias with an ankerite-fluorite matrix. Due to location at the cratonic margin and abundance in the REE, Tajno classifies (Hou et al., 2015) as the carbonatite-associated REE deposit (CARD), and more precisely as the Dalucao-Style orebody (the breccia-hosted orebody). High Fe2O3 (13.8 wt%), MnO (2.1 wt%), total REE (6582 ppm), Sr (43895 ppm), Ba (6426 ppm), F (greater than10000 ppm) and CO2 contents points for the involvement of the slab - including pelagic metalliferous sediments - in the carbonatites formation. Spatial relations and Sr isotope composition ((87Sr/86Sr)i = 0.7043-0.7048; Wiszniewska et al., 2020) of alkali clinopyroxenite and syenite suggest that these are products of differentiation of the magma, generated by the initial melting of the SCLM due to influx of F-rich fluids from subducted marine sediments. Carbonatites Sr isotope composition ((87Sr/86Sr)i = 0.7037-0.7038), and Ba/Th (16-20620) and Nb/Y (0.01-6.25) ratios, link their origin with a more advanced melting of the SCLM, triggered by CO2-rich fluids from the subducted AOC and melts from sediments. The Tajno Massif - and coeval mafic-alkaline intrusions - age, high potassic composition, and location along the craton margin nearly parallel the Variscan deformation front, are suggesting Variscan subduction beneath the EEC. The oxygen isotope compositions of clinopyroxene (?18O value = 5.2‰) and alkali feldspar (?18O value = 5.7‰), from alkali clinopyroxenite and foid syenite, respectively, are consistent with mantle-derived magmas. Isotopic compositions of carbonatites and breccias (carbonate ?18O = 8.7‰ to 10.7‰; ?13C = -4.8‰ to ?0.4‰) span from values of primary carbonatites to carbonatites affected by a fractionation or sedimentary contamination. The highest values (?18O = 10.7‰; ?13C = -0.4‰) were reported for breccia cut by numerous veins confirming post-magmatic hydrothermal alteration. The lowest carbonate ?18O (9.3‰ to 10.7‰) and ?13C (?5.0‰ to ?3.8‰) values are reported for veins in alkali clinopyroxenites, whereas the highest ?18O (11.2‰) and ?13C (?1.2‰ to ?1.1‰) values are for veins in syenites and trachytes. Isotopic composition of veins suggests hydrothermal origin, and interaction with host mantle-derived rocks, as well as country rocks. In silicate rocks of the Tajno Massif, fluid influx leads to the development of Pb, Zn, Cu, Ag, Au sulfide mineralization-bearing stockwork vein system, with carbonate, silicate and fluorite infilling the veins. Bulk-rock contents of molybdenum (925 ppm), rhenium (905 ppb) and palladium (29 ppb) are notable. The Re-rich molybdenite association with galena, pyrite and Th-rich bastnäsite in carbonate veins is similar as in Mo deposits associated with carbonatites, implying the mantle source of Mo and Re.
DS1991-0949
1991
GilbertLambert, D.D., Shirey, S.B., Carlson, R.W., Weaver, B.L., GilbertRhenium- Osmium (Re-Os) and samarium-neodymium (Sm-Nd) isotopic systematics of lamproites and basalts from theEos Transactions, Vol. 72, No. 44, October 29, abstract p. 543Arkansas, MidcontinentLamproites, Geochemistry, geochronology
DS1990-0567
1990
Gilbert, A.E.Gilbert, A.E., Kozmenko, O.A., Shatskiy, V.S.Rare and rare earth elements in Kokchetau massif eclogitesGeochemistry International, Vol. 27, No. 8, pp. 133-136RussiaRare earths, Eclogites
DS1990-0568
1990
Gilbert, A.E.Gilbert, A.E., Kozmenko, O.A., Shatsky, V.S.Rare and rare earth elements in eclogites of the Kokchetav Massif.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 1, January 1990, pp. 141-144RussiaEclogites, Rare earths
DS1993-0543
1993
Gilbert, C.Gilbert, C.Portable GPS systems for mapping features versus benefitsEarth Observation Magazine, Vol. 2, No. 9, October pp. 43, 44, 47, 48GlobalGlobal Positioning system
DS1993-0544
1993
Gilbert, C.Gilbert, C.Portable GPS systems for mapping features versus benefitsEarth Observation Magazine, Vol. 2, No. 9, October pp. 43, 44, 47, 48.GlobalGPS Systems -brief explanation, Global Positioning Systems
DS1996-0524
1996
Gilbert, C.Gilbert, C.Translating GPS dat a to a GIS, CAD system or dat abase format, part IIEom., Dec. pp. 34-35GlobalComputers, GIS, GPS
DS1996-0525
1996
Gilbert, C.Gilbert, C.Translating GPS dat a to a GIS, CAD system or dat abase formatEom., October pp. 38-39GlobalGIS, Database format
DS1996-0526
1996
Gilbert, C.Gilbert, C.Doing a differential correction by handEarth Observation Magazine, Sept. pp. 40-41GlobalGPS -corrections
DS1996-0527
1996
Gilbert, C.Gilbert, C.GPS to record dat a at a fixed location and a laptop recording dat a in thefield... difference for error?Earth Observation Magazine, Sept. pp. 43-45GlobalGPS -corrections
DS1996-0528
1996
Gilbert, C.Gilbert, C.Using GPS with offset information. Part 3 of 3Earth Observation Magazine, May pp. 38-40.GlobalGPS data collection
DS1996-0529
1996
Gilbert, C.Gilbert, C.Using GPS with offset informationEarth Observation Magazine, May, pp. 38-40GlobalGPS data collection
DS1996-0530
1996
Gilbert, C.Gilbert, C.Using GPS with offset information: Laser Rangefinders Part 2Earth Observation Magazine, April, pp. 30-32.GlobalGPS, Laser Rangefinders
DS1996-0531
1996
Gilbert, C.Gilbert, C.How is the accuracy of a GPS receiver described?Earth Observation Magazine, June pp. 44-45GlobalGPS, Accuracy
DS1997-0403
1997
Gilbert, C.Gilbert, C.Batch processing of GPS data, part 2 of 2Eom., March pp. 36-37GlobalComputer, GPS
DS1997-0404
1997
Gilbert, C.Gilbert, C.Select the best type of GPS dat a for your application. Part 2 of 2Eom., October pp. 25-27GlobalComputer, GPS
DS1997-0405
1997
Gilbert, C.Gilbert, C.Translating GPS dat a to GIS, CAD system or dat abase format, Part IIIEom., Jan. pp. 36-37GlobalComputers, GPS
DS1997-0406
1997
Gilbert, C.Gilbert, C.Batch processing of GPS data, part 1 of. 2Eom., Feb. pp. 35-36GlobalComputers, GPS data
DS1997-0407
1997
Gilbert, C.Gilbert, C.Selecting the best type of GPS dat a for your application Part 1 of 2Eom., July pp. 49-50GlobalComputers, GPS data
DS1997-0408
1997
Gilbert, C.Gilbert, C.The vertical components of GPSEom., May pp. 34-35GlobalGPS, Computers
DS1998-0508
1998
Gilbert, C.Gilbert, C.Evolution of GPS dat a collection for GISEom., Feb. pp. 27-28GlobalComputer, GIS data
DS200812-0410
2008
Gilbert, C.D.Gilbert, C.D., William-Jones, A.E.Vapour transport of rare earth elements ( REE) in volcanic gas: evidence from encrustations at Oldoinyo Lengai.Journal of Volcanology and Geothermal Research, Vol. 178, 4, Oct. 15, pp. 519-528.Africa, TanzaniaNatrocarbonatite
DS1987-0795
1987
Gilbert, C>M.Williams, H., Turner, F.J., Gilbert, C>M.Petrography - an introduction to the study of rocks in thin sectionsFreeman and Co, pp. 227-259GlobalLamprophyres, Alkalic Rocks
DS1975-0515
1977
Gilbert, E.Gilbert, E., et al.Neutron activation determination of noble metals for the analysis of technological and natural materials.Journal of Radioanalyt. Chem., Vol. 38, pp. 147-54.GlobalGeochemistry - Not Specific To Diamonds, Platinum Group
DS200712-0361
2007
Gilbert, H.Gilbert, H., Velasco, A.A., Zandt, G.Preservation of Proterozoic terrane boundaries within the Colorado Plateau and implications for its tectonic evolution.Earth and Planetary Science Letters, Vol. 256, 1-2, June 15, pp. 237-248.United States, Colorado PlateauTectonics
DS201706-1095
2017
Gilbert, H.Marshak, S., Domrois, S., Abert, C., Larson, T., Pavlis, G., Hamburger, M., Yang, X., Gilbert, H., Chen, C.The basement revealed: tectonic insight from a digital elevation model of the Great Unconformity, USA cratonic platform.Geology, Vol. 45, 5, pp. 391-394.United Statestectonics - Mid continent

Abstract: Across much of North America, the contact between Precambrian basement and Paleozoic strata is the Great Unconformity, a surface that represents a >0.4 b.y.-long hiatus. A digital elevation model (DEM) of this surface visually highlights regional-scale variability in the character of basement topography across the United States cratonic platform. Specifically, it delineates Phanerozoic tectonic domains, each characterized by a distinct structural wavelength (horizontal distance between adjacent highs) and/or structural amplitude (vertical distance between adjacent lows and highs). The largest domain, the Midcontinent domain, includes long-wavelength epeirogenic basins and domes, as well as fault-controlled steps. The pronounced change in land-surface elevation at the Rocky Mountain Front coincides with the western edge of the Midcontinent domain on the basement DEM. In the Rocky Mountain and Colorado Plateau domains, west of the Rocky Mountain Front, structural wavelength is significantly shorter and structural amplitude significantly higher than in the Midcontinent domain. The Bordering Basins domain outlines the southern and eastern edges of the Midcontinent domain. As emphasized by the basement DEM, several kilometers of structural relief occur across the boundary between these two domains, even though this boundary does not stand out on ground-surface topography. A plot of epicenters on the basement DEM supports models associating intraplate seismicity with the Midcontinent domain edge. Notably, certain changes in crustal thickness also coincide with distinct changes in basement depth.
DS2001-0381
2001
Gilbert, H.J.Gilbert, H.J., Sheehan, A.F., Webb, S.Upper mantle discontinuity structure in the region of the Tonga subductionzone.Geophysical Research Letters, Vol. 28, No. 9, May 1, pp. 1855-8.MantleSubduction
DS2003-0465
2003
Gilbert, H.J.Gilbert, H.J., Sheehan, A.F., Dueker, K.G., Molnar, P.Receiver functions in the western United States with implications for upper mantleJournal of Geophysical Research, Vol. 108, B5, May 1, 10.1029/2002JB001194.Colorado, WyomingGeophysics - seismics
DS2003-0466
2003
Gilbert, H.J.Gilbert, H.J., Sheehan, A.F., Dueker, K.G., Molnar, P.Receiver functions in the western United States, with implications for upper mantleJournal of Geophysical Research, Vol. 108, 5, ETG3 DOI 10.1029/2002JB001194.United States, Colorado, WyomingGeophysics - seismics
DS200412-0663
2004
Gilbert, H.J.Gilbert, H.J., Sheehan, A.F.Images of crustal variations in the intermountain west.Journal of Geophysical Research, Vol. 109, B3, 10.1029/2003JB002730TechnologyTomography
DS200412-0664
2003
Gilbert, H.J.Gilbert, H.J., Sheehan, A.F., Dueker, K.G., Molnar, P.Receiver functions in the western United States, with implications for upper mantle structure and dynamics.Journal of Geophysical Research, Vol. 108, 5, ETG3 DOI 10.1029/2002 JB001194.United States, Colorado PlateauGeophysics - seismics
DS1986-0289
1986
Gilbert, J.M.Gilbert, J.M., Park, C.F.Jr.Kimberlites-diamond and carbonatites-PalaboraIn: Geology of ore deposits, W.H. Freeman and Co, pp. 436-452South AfricaCarbonatite
DS1998-0509
1998
Gilbert, J.S.Gilbert, J.S.The physics of explosive volcanic eruptionsGeological Society of London Spec. Publishing, No. 145, 192p. $ 98.00 United StatesGlobalMagmas, fragmentation - not specific to diamonds
DS1998-0510
1998
Gilbert, J.S.Gilbert, J.S., Sparks, R.S.J.Future research directions on the physics of explosive volcanic eruptionsGilbert and Sparks, Geological Society of London, No. 145, pp. 1-7.GlobalVolcanic processes - not specific to diamonds
DS1998-1388
1998
Gilbert, J.S.Sparks, R.S.J., Gilbert, J.S.The physics of explosive volcanic eruptionsGeological Society of London Spec. Pub, No. 145, 192p. $ 98.00GlobalBook - ad, Magma, flow, fragmentation, phretomagmatic
DS1986-0290
1986
Gilbert, L.A.Gilbert, L.A., Foland, K.A.The Mont St. Hilaire plutonic complex: occurrence of excess 40Ar and short intrusion historyCanadian Journal of Earth Sciences, Vol. 23, No. 7, July pp. 948-958QuebecCarbonatite
DS1970-0818
1973
Gilbert, M.C.Sears, C.E., Gilbert, M.C.Petrography of the Mt. Horeb Virginia, PeridotiteGeological Society of America (GSA), Vol. 5, No. 5, P. 434. (abstract.).Appalachia, VirginiaPetrography
DS1975-0404
1976
Gilbert, M.C.Sears, C.E., Gilbert, M.C.Nature of Central Appalachian KimberlitesEos, Vol. 57, No. 10, P. 761. (abstract.).Appalachia, VirginiaKimberlite, Mt. Horeb, Heavy Minerals
DS1983-0253
1983
Gilbert, M.C.Gilbert, M.C.Timing and chemistry of igneous events associated with the southern Oklahoma aulocogen.Tectonophysics, Vol. 94, pp. 439-55.GlobalTectonics, Magmatism
DS1983-0254
1983
Gilbert, M.C.Gilbert, M.C.Timing and Chemistry of Igneous Events Associated with the Southern Oklahoma Aulacogen.Tectonophysics, Vol. 94, No. 1-4, PP. 439-455.OklahomaMid-continent
DS1986-0291
1986
Gilbert, M.C.Gilbert, M.C., McConnell, D.A.The southern margin of North American craton: problems and constraints on possible modelsGeological Society of America (GSA) Abstract Volume, Vol. 18, No. 6, p. 613. (abstract.)MidcontinentBlank
DS1989-0511
1989
Gilbert, M.C.Gilbert, M.C.Cambrian rifting in the southern Midcontinent of the United States: processes andconsequencesEos, Vol. 70, No. 43, October 24, p. 1343. AbstractMidcontinentTectonics, Rifting
DS1990-0569
1990
Gilbert, M.C.Gilbert, M.C.Southern midcontinent -Texas transect: overview and statement of the tectonic problemsGeological Society of America (GSA) Abstracts with programs, South-Central, Vol. 22, No. 1, p. 6GlobalMidcontinent, Tectonics
DS1990-1003
1990
Gilbert, M.C.McConnell, D.A., Gilbert, M.C.Cambrian extensional tectonics and magmatism within the Southern Oklohomaaulocogen.Tectonophysics, Vol. 174, pp. 147-57.GlobalMidcontinent Rifting, Tectonics
DS1998-0630
1998
Gilbert, M.C.Hogan, J.P., Price, J.D., Gilbert, M.C.Magma traps and driving pressure: consequences for pluton shape and emplacement in an extensional regime.Journal of Structural Geology, Vol. 20, No. 9/10, Sept. pp. 1155-68.GlobalTectonics, structure, Not specific to diamonds
DS200712-0192
2007
Gilbert, M.C.Cloos, M., Carlson, W.D., Gilbert, M.C., Liou, J.G., Sorensen, S.S.Convergent margin terranes and associated regions: a tribute to W.G. Ernst.Geological Society of America, Special Publication 419, 273p. $ 70.00GlobalConference book - geotectonics
DS201904-0715
2019
Gilbert, S.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
Gilbert, S.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.
DS202112-1952
2021
Gilbert Corder, S.N.Tschauner, O., Huang, S., Yang, S., Humayun, M., Liu, W., Gilbert Corder, S.N., Bechtel, H.A., Tischler, J., Rossman, G.R.Nature discovery of davemaoite, CaSiO3-perovskite, as a mineral from the lower mantle. Science, Vol. 374, 6569, pp. 891-894. pdfMantlemineralogy

Abstract: Calcium silicate perovskite, CaSiO3, is arguably the most geochemically important phase in the lower mantle, because it concentrates elements that are incompatible in the upper mantle, including the heat-generating elements thorium and uranium, which have half-lives longer than the geologic history of Earth. We report CaSiO3-perovskite as an approved mineral (IMA2020-012a) with the name davemaoite. The natural specimen of davemaoite proves the existence of compositional heterogeneity within the lower mantle. Our observations indicate that davemaoite also hosts potassium in addition to uranium and thorium in its structure. Hence, the regional and global abundances of davemaoite influence the heat budget of the deep mantle, where the mineral is thermodynamically stable.
DS200512-0751
2004
GilbertsonMoses, 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
DS200712-0362
2006
Gilbertson, A.Gilbertson, A.The evolution of the American round brilliant diamonds... 1860-1955.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.133. abstract onlyTechnologyDiamond cutting
DS201012-0235
2009
Gilbertson, A.Gilbertson, A., Gudlewski, B., Jhonson, M., Maltezos, G., Scherer, A., Shigley, J.Cutting diffraction gratings to improve dispersion ( 'fire') in diamonds. A new process of plasma eteching diffraction patterns on diamond facets.Gems & Gemology, Vol. 45, 4, Winter pp. 260-270.TechnologyDiamond cutting
DS201212-0648
2012
Gilbertson, A.Shigley, J.E., Gilbertson, A., Eaton-Magana, S.Characteristics of colorless coated cubic zirconia ( Diamantine).Gems & Gemology, Vol. 48, 1, pp.TechnologyDiamantine
DS200912-0380
2008
Gilbertson, A.M.King, J.M., Geurts, R.H., Gilbertson, A.M., Shigley, J.E.Color grading 'D-to-Z' diamonds at the GIA laboratory.Gems & Gemology, Vol. 44, 4, pp. 296-321.TechnologyDiamond colours
DS201312-0307
2011
Gilbertson, A.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
DS1991-1182
1991
Gilbertson, J.P.Mooers, H.D., Hobbs, H.C., Gilbertson, J.P.Correlation of Late Wisconsin ice margins in MinnesotaGeological Society of America, Abstract Volume, Vol. 23, No. 3, March p. 50MinnesotaGeomorphology, Glacial
DS200812-0146
2008
Gilbertson, M.Brown, R.J., Field, M., Gernon, T., Gilbertson, M., Sparks, R.S.J.Problems with in vent column collapse model for the emplacement of massive volcaniclastic kimberlite. Discussion of Porritt - Fox kimberliteJournal of Volcanology and Geothermal Research, in press available 8p.Canada, Northwest territoriesFox kimberlite petrology
DS200812-1100
2007
Gilbertson, M.Sparks, R.S., Brown, R.J., Field, M., Gilbertson, M.Kimberlite ascent and eruption.Nature, Vol. 450, 7172, p. E21.TechnologyClassification
DS200612-0447
2006
Gilbertson, M.A.Gernon, T.M., Gilbertson, M.A., Sparks, R.S.J., Walters, A., Field, M.Gas solid fluidisation in an experimental tapered bed: insights into processes in diverging volcanic conduits.Emplacement Workshop held September, 5p. extended abstractTechnologyFluidisation, emplacement
DS200812-0397
2008
Gilbertson, M.A.Gernon, T.M., Gilbertson, M.A., Sparks, R.S.J., Field, M.Gas fluidization in an experimental tapered bed: insights into processes in diverging volcanic conduits.Journal of Volcanology and Geothermal Research, Vol. 174, 1-3, pp. 49-56.TechnologyEmplacement, diatreme
DS200912-0248
2009
Gilbertson, M.A.Gernon, T.M., Gilbertson, M.A., Sparks, R.S.J., Field, M.The role of gas fluidization in the formation of massive volcanoclastic kimberlite.Lithos, In press available 33p.MantleFluidization
DS200612-0459
2006
Gilborn, R.Gilborn, R.Reasonable cause: policies to test employees for drug or alcohol use... legal minefields.Canadian Diamonds, Winter, p. 14,16,42,44.Canada, Northwest TerritoriesNews item - legal
DS202112-1927
2021
Gilbouin, D.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.
DS1990-0570
1990
Gilchrist, A.R.Gilchrist, A.R., Summerfield, M.A.Differential denudation and flexural isostasy in formation of rifted marginupwarpsNature, Vol. 346, No. 6286, August 23, pp. 739-741GlobalTectonics, Rifted margins
DS1988-0255
1988
Gilchrist, I.C.R.Gilchrist, I.C.R., Hunt, M.S.The recovery of water from a colloidally stable kimberlite suspensionInternational Mine Water Congress, 3rd. AusIMM, pp. 131-145AustraliaWastewater, Mineral processing
DS1990-0571
1990
Gilchrist, I.C.R.Gilchrist, I.C.R.Clarification of Premier mine slimesInternational Deep Mining Conference, held Johannesburg Sept. 17-21, 1990. Sth. Afr., Vol. 1, pp. 73-80South AfricaMining - Premier, Mineral Processing
DS1900-0319
1905
Gilchrist, J.D.F.Flint, W., Gilchrist, J.D.F.Science in South Africa. a Handbook and ReviewCape Town: Maskew Miller., 505P.Africa, South AfricaHistory, Kimberley
DS1996-1587
1996
Gilder, S.A.Zhai, X., Coe, R.S., Gilder, S.A., Frost, G.M.Paleomagnetic constraints on the paleogeography of China: implications forGondwanaland.Australian Journal of Earth Sciences, Vol. 43, pp. 643-672.ChinaPaleomagnetism, Tectonics
DS1996-1603
1996
Gilder, S.A.Zhao, X., Coe, R.S., Gilder, S.A., Frost, G.M.Paleomagnetic constraints on the paeogeography of China: implications forGondwanalandAustralian Journal of Earth Sciences, Vol. 43, pp. 643-672Australia, ChinaPaleomagnetism, Tarim, Tectonics
DS200712-0767
2007
Gilder, S.A.Muundjua, M., Hart, R.J., Gilder, S.A., Carporzen, L., Galdeano, A.Magnetic imaging of the Vredefort impact crater, South Africa.Earth and Planetary Science Letters, Vol. 261, 3-4, pp. 456-468.Africa, South AfricaGeophysics
DS2002-0149
2002
Giles, D.Betts, P.G., Giles, D., Lister, G.S., Frick, L.R.Evolution of the Australian lithosphereAustralian Journal of Earth Sciences, Vol. 49,4,August pp. 661-96.AustraliaMantle - geodynamics
DS2002-0570
2002
Giles, D.Giles, D.Southward growth of Australia in the paleo and mesoproterozoic accretionary margin of pre-Rodinian supercontinent?Geological Society of America Annual Meeting Oct. 27-30, Abstract p. 559.AustraliaTectonics, Gondwana
DS2002-0571
2002
Giles, D.Giles, D., Betts, P., Lister, G.Far field continental backarc setting for the 1.80 - 1.67 Ga basins of northeastern Australia.Geology, Vol. 30,9,Sept. pp. 823-6.AustraliaTectonics - plates, Proterozoic
DS200712-0076
2007
Giles, D.Betts, P.G., Giles, D., SChaefer, B.F., Mark, G.1600 -1500 Ma hotspot track in eastern Australia: implications for Mesoproterozoic continental reconstruction.Terra Nova, Vol. 19, 6, pp. 496-501.AustraliaHotspots, plumes
DS201112-0086
2011
Giles, D.Betts, P.G., Giles, D., Aitken, A.Paleoproterozoic accretion processes of Australia and comparisons with Laurentia.International Geology Review, Vol. 53, no. 11-12, pp. 1357-1376.Australia, CanadaTectonics
DS201412-0292
2014
Giles, D.Giles, D., Hillis, R., Clverely, J.Deep exploration technologies provide the pathway to deep discovery.SEG Newsletter, No. 97, April pp. 1, 23-27.TechnologyNot specific to diamonds
DS201606-1078
2016
Giles, D.Betts, P.G., Armit, R.J., Stewart, J., Aitken, A.R.A., Aileres, L., Donchak, P., Hutton, L., Withnall, I., Giles, D.Australia and Nuna.Geological Society of London Special Publication Supercontinent Cycles through Earth History., Vol. 424, pp. 47-81.AustraliaSupercontinents

Abstract: The Australian continent records c. 1860-1800 Ma orogenesis associated with rapid accretion of several ribbon micro-continents along the southern and eastern margins of the proto-North Australian Craton during Nuna assembly. The boundaries of these accreted micro-continents are imaged in crustal-scale seismic reflection data, and regional gravity and aeromagnetic datasets. Continental growth (c. 1860-1850 Ma) along the southern margin of the proto-North Australian Craton is recorded by the accretion of a micro-continent that included the Aileron Terrane (northern Arunta Inlier) and the Gawler Craton. Eastward growth of the North Australian Craton occurred during the accretion of the Numil Terrane and the Abingdon Seismic Province, which forms part of a broader zone of collision between the northwestern margins of Laurentia and the proto-North Australian Craton. The Tickalara Arc initially accreted with the Kimberley Craton at c. 1850 Ma and together these collided with the proto-North Australian Craton at c. 1820 Ma. Collision between the West Australian Craton and the proto-North Australian Craton at c. 1790-1760 Ma terminated the rapid growth of the Australian continent.
DS200712-1025
2006
Giles, G.Spera, F.J., Yuen, D.A., Giles, G.Tradeoffs in chemical and thermal variations in the post perovskite phase transition: mixed phase regions in the deep lower mantle?Physics of the Earth and Planetary Interiors, Vol. 159, 3-4, Dec. pp. 234-246.MantleGeothermometry
DS1960-0147
1961
Giles, G.S.Giles, G.S.Diamond Mining Practice in South AfricaSouth African Institute of Mining and Metallurgy. Journal, Vol. 61, SEPT. PP. 839-850.South AfricaDiamond Mining Recovery, Kimberlite Pipes
DS1995-0632
1995
Giles, J.R.A.Giles, J.R.A.Geological dat a managementGeological Society Publishing House, GlobalData Management, Book -ad
DS1997-0063
1997
Giles, J.R.A.Bain, K.A., Giles, J.R.A.A standard model for storage of geological map dataComputers and Geosciences, Vol. 23, No. 6, pp. 613-620GlobalMapping, Computers - Program
DS1997-0409
1997
Giles, J.R.A.Giles, J.R.A., Lowe, D.J., Bain, K.A.Geological dictionaries - critical elements of every geological databaseComputers and Geosciences, Vol. 23, No. 6, pp. 621-26GlobalDictionary, Computers - Program
DS1960-1092
1969
Giletti, B.J.Damon, P.E., Giletti, B.J.The Age of the Basement Rocks of the Colorado Plateau and Adjacent Areas.New York Academy of Sciences Annual, Vol. 91, PP. 443-453.United States, Colorado PlateauBlank
DS1860-0143
1871
Gilfillan, G.F.Gilfillan, G.F.On the Diamond Districts of the Cape of Good HopeQuarterly Journal of Geological Society (London), Vol. 27, PT. 1, PP. 72-73. ALSO: 1871 Geology Magazine, Vol. 8, PPAfrica, South Africa, Cape Province, Vaal RiverGeology
DS1997-0410
1997
Gilfillan, J.Gilfillan, J.Reporting mineral resources and ore reserves - the ASX, the JORC codes And the AusIMM: are you a competent ..Australian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 5, Aug, pp. 23-24AustraliaEconomics, ore reserves, geostatistics, Legal, reporting
DS2000-0337
2000
Gilfillan, J.F.Gilfillan, J.F.Testing the dat a - the role of technical due diligenceMin. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 505-10.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS2000-0338
2000
Gilfillan, J.F.Gilfillan, J.F.The resource database auditMin. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 91-6.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS2000-0339
2000
Gilfillan, J.F.Gilfillan, J.F., Levy, I.W.Monitoring the reserveMin. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 537-44.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS2000-0932
2000
Gilfillan, J.F.Stoker, P.T., Gilfillan, J.F.The resource database audit.Min. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 31-6.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS201912-2784
2019
Gilfillan, S.M.V.Gilfillan, S.M.V., Gyore, D., Flude, S., Johnson, G., Bond, C.E., Hicks, N., Lister, R., Jones, D.G., Kremer, Y., Hazeldine, R.S., Stuart, F.M.Noble gases confirm plume related mantle degassing beneath southern Africa.Nature Communications, Vol. 10, 1, 10.1038/s41467-019-1244-6Africa, South Africaplumes

Abstract: Southern Africa is characterised by unusually elevated topography and abnormal heat flow. This can be explained by thermal perturbation of the mantle, but the origin of this is unclear. Geophysics has not detected a thermal anomaly in the upper mantle and there is no geochemical evidence of an asthenosphere mantle contribution to the Cenozoic volcanic record of the region. Here we show that natural CO2 seeps along the Ntlakwe-Bongwan fault within KwaZulu-Natal, South Africa, have C-He isotope systematics that support an origin from degassing mantle melts. Neon isotopes indicate that the melts originate from a deep mantle source that is similar to the mantle plume beneath Réunion, rather than the convecting upper mantle or sub-continental lithosphere. This confirms the existence of the Quathlamba mantle plume and importantly provides the first evidence in support of upwelling deep mantle beneath Southern Africa, helping to explain the regions elevation and abnormal heat flow.
DS1999-0011
1999
Gilg, H.A.Andrade, F.R.D., Moller, P., Gilg, H.A.Hydrothermal rare earth elements mineralization in the Barra do Itapirapuacarbonatite, trace elements and C, OChemical Geology, Vol. 155, No. 1-2, Mar. 1, pp. 91-114.Brazilrare earth elements (REE), inclusions, Carbonatite
DS201312-0615
2013
Gilg, H.A.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
DS201704-0646
2017
Gilg, H.A.Schmetzer, K., Gilg, H.A., Vaupel, E.Synthetic emeralds grown by Richard Nacken in the mid-1920's: properties, growth technique, and historical account.Gems & Gemology, Vol. 52, 4, pp. 368-392.Europe, GermanySynthetic - emeralds

Abstract: Chemical and microscopic examination of the first gem-quality synthetic emeralds of facetable size proves that Prof. Richard Nacken grew two main types of emerald by flux methods in the mid-1920s. One of these two types, grown with colorless beryl seeds in molybdenum-bearing and vanadium-free fluxes, has not previously been mentioned in the literature and would appear to be unknown to gemologists. The other main type, which has already been described in gemological publications, was grown from molybdenum- and vanadium-bearing fluxes. In drawing these conclusions, rough and faceted synthetic emeralds produced by Nacken were available for study from two principal sources: the Deutsches Museum in Munich, to which Nacken had donated samples in 1961, and family members who had inherited such crystals. Chemical, morphological, and microscopic properties are given, and circumstances concerning the developmental history of the Nacken production, including the possibility of collaboration with IG Farben (a subject of past speculation), are discussed as well. The latter has recently been elucidated by the discovery of original documents from the IG Farben gemstone plant, preserved in the Archives of the German Federal State of Saxony-Anhalt.
DS201909-2023
2019
Gilholy, W.P.Bosco-Santos, A., Gilholy, W.P., Fouskas, F., Baldim, M., Oliveira, E.P.Ferruginous - euxinc - oxic: a three step redox change in the Neoarchean record.Goldschmidt2019, 1p. AbstractSouth America, Brazilcraton

Abstract: Much of the secular record of sulfur mass independet fractionation (S-MIF) is based on pyrites extracted from a limited number of formations from Western Australia and Southern Africa. Here we present multiproxy evidence for an episodic loss of S-MIF in sulfides from a 2.7 Ga sedimentary record in the São Francisco craton, Brazil. Based on combined proxies, we assigned three phases, in a continous drill core, that track evolving water column redox conditions and changes in ecology. In Phase-I, the stratigraphically older rocks, reactive iron ratios suggest ferruginous conditions. The pyrites have modest S-MIF values (D33S from -0.7 to 2.6‰) and the carbon isotope composition of the iron formations is indicative of carbon fixation by anoxygenic photosynthetic bacteria that oxidized Fe2+ (d13Corg from -27.7 to -17.5‰). Within Phase-II, an intermediate phase characterized by graphite schist, the iron ratios, expansion of the S-MIF (D33S from 2.15 to 3.4‰) and an excess of Mo relative to Corg suggest deposition in an anoxic environment with periodic development of euxinic conditions. Phase-III culminates in fully oxic conditions with a loss of S-MIF and emergence of sulfur mass dependent fractionation (S-MDF) with homogeneous d34S pyrite values (average = 3.3 ± 0.5‰). The loss of S-MIF in the Archean sulfides of Phase-III was interpreted as a response to increased oxygen levels that lead to an intensification of oxidative weathering. Based on the continous deposition within this drillcore, the development of more oxidizing conditions may have been relatively rapid, reinforcing the model that the transition from S-MIF to S-MDF can happen on rapid geological time scales and was recorded about 400 million years prior to the GOE in the Brazilian craton.
DS201708-1649
2017
Gilika, O.Gilika, O.Building a geometallurgical model for Orapa mine, Botswana.11th. International Kimberlite Conference, PosterAfrica, Botswanadeposit - Orapa
DS1984-0304
1984
Gilinskaya, L.G.Gilinskaya, L.G., Egorov, L.S.Esr Spectra of Apatites of the Maimecha Kotuj Ijolite Carbonatite Complex.Geochemistry International (Geokhimiya)., No. 12, DECEMBER PP. 1858-1866.RussiaCarbonatite
DS1985-0234
1985
Gilinskaya, L.G.Gilinskaya, L.G., Yegorov, L.S.Esr Spectra of Apatite from the Maymecha-kotuy IjolitecarbonatitecomplexGeochemistry International, Vol. 22, No. 5, pp. 1-8RussiaCarbonatite, Ijolite
DS201507-0313
2015
Gilio, M.Gilio, M., Clos, F., Van Roermund, H.L.M.The Frimingen garnet peridotite ( central Swedish Caledonides). A good example of the characteristic PTt path of a cold mantle wedge garnet peridotite.Lithos, Vol. 230, pp. 1-16.Europe, SwedenPeridotite
DS201212-0491
2012
Gilisovic, P.Morrow, E., Mitrovica, J.X., Forte, A.M., Gilisovic, P., Huybers, P.An enigma in estimates of the Earth's dynamic ellipticity.Geophysical Journal International, in press availableMantleGeodynamics
DS1998-0904
1998
GillLundstrom, C.C., Shaw, Ryerson, Williams, GillCrystal chemistry control of clinopyroxene melt partioning in the Di Ab Ansystem: implications for elemental fractionations in the depleted mantle.Geochimica et Cosmochimica Acta, Vol. 62, No. 16, pp. 2849-62.MantleGeochemistry
DS1997-0411
1997
Gill, C.Gill, C., Marrs, R.Detection of kimberlite pipes in the Colorado - Wyoming State Line District using AVARIS.Twelfth Geologic Remote Sensing, Nov. 17th., AbstractsColorado, WyomingGeophysics - remote sensing, AVARIS
DS1860-0104
1870
Gill, J.Gill, J.The Emigrant's Guide to the South African Diamond FieldsLondon: Sampson Low, Marsden., 16P.Africa, South Africa, Cape ProvinceGuidebook, History
DS201212-0105
2012
Gill, J.Campbell, I., Gill, J., Iizuka, T., Allen, C.What detrital zircons tell us about growth of the continental crust.Goldschmidt Conference 2012, abstract 1p.MantleGeochronology
DS1986-0862
1986
Gill, J.B.Williams, R.W., Gill, J.B., Bruland, K.W.Ra Th disequilibration temperatures systematics-timescale of carbonatite magma formation at Oldoiny Lengai volcano, TanzaniaGeochimica et Cosmochimica Acta, Vol. 50, No. 6, June pp. 1249-1259TanzaniaCarbonatite
DS1991-0574
1991
Gill, J.B.Gill, J.B., Pyle, D.M., Williams, R.W.Igneous rocksMineralogical Association of Canada -Short Course Handbook, Vol. 19, Chapter 9, pp. 287-335GlobalGeochronology, Magmatic evolution, volcanoes
DS1992-1670
1992
Gill, J.B.Williams, R.W., Collerson, K.D., Gill, J.B., Deniel, C.High Th/U ratios in subcontinental lithospheric mantle: mass spectrometric measurement of Th isotopes in Gaussberg lamproitesEarth and Planetary Science Letters, Vol. 111, No. 2-4, July pp. 257-268MantleGeochronology, Lamproites
DS200612-0460
2006
Gill, J.B.Gill, J.B., Tollstrup, D., Todd, E.Hf mobility and immobility in subduction zones.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 17, abstract only.MantleSubduction
DS201312-0432
2013
Gill, J.B.Izuka, T., Campbell, I.H., Allen, C.M., Gill, J.B., Maruyama, S., Makota, F.Evolution of the African continental crust as recorded by U-Pb, Lu-Hf and O isotopes in detrital zircons from modern rivers.Geochimica et Cosmochimica Acta, Vol. Pp. 96-120.AfricaGeochronology, Comgo, Zambesi, Orange
DS1981-0180
1981
Gill, M.Gill, M.Ashton Reports Consistent on Sampling But Wide on ValueThe Age (melbourne), APRIL 16TH.Australia, Western Australia, Kimberley RegionSampling, Valuation, Cra, Pipe
DS200712-0668
2007
Gill, R.Maier, R., Heinson, G., Thiel, S., Selway, K., Gill, R., Scroggs, M.A 3D lithospheric resistivity model of the Gawler Craton: southern Australia.Transactions of the Institution of Mining and Metallurgy, Vol. 116, 1, pp. 13-21.AustraliaGeophysics - resistivity
DS200512-0337
2004
Gill, R.C.Gill, R.C., Aparicio, A., El Azzouzi, M., Hernandez, J., Thirlwall, M.F., Bourgois, J., Marriner, G.F.Depleted arc volcanism in the Alboran Sea and shoshonitic volcanism in Morocco: geochemical and isotopic constraints on Neogene tectonic processes.Lithos, Vol. 78, 4, pp. 363-388.Africa, MoroccoShoshonite
DS1992-0567
1992
Gill, R.C.O.Gill, R.C.O., Pedersen, A.K., Larsen, J.G.Tertiary picrites in West Greenland: melting at the periphery of a plume?Geological Society Special Publication, Magmatism and the Causes of Continental, No. 68, pp. 335-348GreenlandPicrites, Plume
DS1992-0721
1992
Gill, R.C.O.Holm, P.M., Gill, R.C.O., Pedersen, A.K., Larsen, J.G., Hald, N.The Icelandic mantle plume: compositional constraints from the West Greenland Tertiary picritesEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.336GreenlandPicrites, Mantle plume
DS1993-0694
1993
Gill, R.C.O.Holm, P.M., Gill, R.C.O., Pedersen, A.K., Larsen, J.G., Hald, N.The Tertiary picrites of West Greenland: contributions from Icelandic and other sourcesEarth and Planetary Science Letters, Vol. 115, No. 1-4, March pp. 227-244GreenlandPicrites, Alkaline rocks
DS1995-0633
1995
Gill, R.C.O.Gill, R.C.O., Holm, NielsenWas a short lived Baffin Bay plume active prior to initiation of present Icelandic plume? clues from high magnesium picrites of west Greenland.L.Lithos, Vol. 34, pp. 27-39.GlobalMantle - plumes, Picrites
DS1995-0634
1995
Gill, R.C.O.Gill, R.C.O., Holm, P.M., Nielsen, T.F.D.Was a short lived Baffin Bay plume active prior to initiation of the present Icelandic plume? Clues ..Lithos, Vol. 34, No. 1-3, Jan. pp. 27-40GreenlandPicrite -magnesiuM., Plume
DS200812-0297
2008
Gill, T.I.Doyle, B.J., Gill, T.I., Thompson, V.The discovery of the Dharma kimberlite complex: evidence for a previously unknown Archean terrain north of Great Bear Lake.Northwest Territories Geoscience Office, p. 21. abstractCanada, Northwest TerritoriesBrief overview - Sanatana, Kennecott
DS200412-0741
2004
Gillan, M.Gubbins, D., Alfe, D., Masters, G., Price, G.D., Gillan, M.Gross thermodynamics of two component core convection.Geophysical Journal International, Vol. 157, 3, pp. 1407-1414.MantleConvection
DS2002-0020
2002
Gillan, M.J.Alfe, D., Gillan, M.J., Price, G.D.Composition and temperature of the Earth's core constrained by combining ab initio calculations/seismicEarth and Planetary Science Letters, Vol. 195, No. 1-2, pp. 91-8.MantleGeophysics - seismics, Geochemistry
DS2003-0007
2003
Gillan, M.J.Alfe, D., Gillan, M.J., Price, G.D.Thermodynamics from first principles: temperature and composition of the Earth's coreMineralogical Magazine, Vol. 67, 1, pp. 113-24.MantleGeothermometry
DS2003-0008
2003
Gillan, M.J.Alfe, D., Gillan, M.J., Price, G.D.Thermodynamics from first principles: temperature and composition of the Earth's coreMineralogical Magazine, Vol. 67, 1, Feb. pp. 113-124.MantleGeothermometry
DS201912-2833
2019
Gillander, A.Welsh, M., Gillander, A.Diamond policy framework.Yellowknife Forum NWTgeoscience.ca, abstract volume p. 97.Canada, Northwest Territorieslegal

Abstract: Established in 1999, the Diamond Policy Framework (DPF) was designed to facilitate the development of a diamond manufacturing industry in the Northwest Territories (NWT). In addition, agreements with NWT diamond producers were established which required them to offer 10 percent of their production, by value, to Approved NWT Diamond Manufacturers (ANDM) for manufacturing in the NWT. The NWT is the most expensive jurisdiction in which to operate a manufacturing facility and despite some early success, the policy was not successful in creating an operating environment for the secondary industry to flourish. In 2018, ITI commissioned a review of the DPF that sought recommendations on how to make this industry more attractive to investors. The report contained a detailed review of the global diamond market. It also presented a series of cost per carat analyses of NWT production costs versus costs in other diamond manufacturing regions. Policy recommendations included adopting an export provision for NWT rough diamonds (and making that export volume contingent on their investment in the NWT), permitting the development of a facility for high-skill planning and lasering services, and generally ensuring that the policy supported the acceptance of innovative business plans. In 2018, The Department of Industry, Tourism and Investment (ITI) amended the DPF. Accordingly, a new approach to the utilization of rough diamonds was developed to realize maximum economic benefits for the NWT and its residents. The amended DPF now has provisions that allow an ANDM to export a portion of their allocation based on their business proposal and an ANDM is no longer required to complete the entire manufacturing process in the NWT. To be eligible to export rough diamonds, ANDM applicants must provide a comprehensive business plan that outlines investment details. Business plans are reviewed and scored based on a comprehensive matrix that determines the export volume.
DS1997-0984
1997
Gillen, C.Rundqvist, D.V., Gillen, C.Precambrian ore deposits of the East European and Siberian CratonsElsevier, 470pRussia, Baltic States, Kola, AldanBook - ad, Mineral deposits
DS1995-0635
1995
Gillespie, A.Gillespie, A., Molnar, P.Asynchronous maximum advances of mountain and continental glaciersReviews of Geophysics, Vol. 33, No. 3, August pp. 311-364.GlobalGeomorphology, Glaciation patterns
DS200612-0975
2006
Gillespie, A.Nichols, K.K., Bierman, P.R., Fonini, W.R., Gillespie, A., Caffee, M., Finkel, R.Dates and rates of arid region geomorphic process.GSA Today, August pp. 4- 11.United States, California, ArizonaGeomorphology, desert landscapes
DS201904-0715
2019
Gillespie, J.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
Gillespie, J.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.
DS1999-0251
1999
Gillespie, M.R.Gillespie, M.R., Styles, M.T.Rock classification, igneous rocksBritish Geological Survey, No. 99-06, 52p.GlobalClassification - igneous rocks
DS200412-0665
1999
Gillespie, M.R.Gillespie, M.R., Styles, M.T.Rock classification, igneous rocks.British Geological Survey, No. 99-06, 52p.TechnologyClassification - igneous rocks
DS200712-0956
2007
Gillespie, M.R.Schofield, D.I., Gillespie, M.R.A tectonic interpretation of Eburean terrane outliers in the Reguelen Shield, Mauritania.Journal of African Earth Sciences, Vol. 49, 4-5, pp. 179-186.Africa, MauritaniaTectonics
DS2002-0906
2002
GilletKunz, M., Gillet, Fiquet, Sautter, Graafsma, ConradCombined in situ x-ray diffraction and raman spectroscopy on majoritic garnet inclusions in diamondsEarth and Planetary Science Letters, Vol.198,3-4,pp.485-93., Vol.198,3-4,pp.485-93.GlobalSpectroscopy, Diamond inclusions
DS2002-0907
2002
GilletKunz, M., Gillet, Fiquet, Sautter, Graafsma, ConradCombined in situ x-ray diffraction and raman spectroscopy on majoritic garnet inclusions in diamondsEarth and Planetary Science Letters, Vol.198,3-4,pp.485-93., Vol.198,3-4,pp.485-93.GlobalSpectroscopy, Diamond inclusions
DS1992-0568
1992
Gillet, P.Gillet, P., Fiquet, G., Malesieux, J-M., Geiger, C.A.high pressure and high temperature Raman spectroscopy of end membergarnets: pyrope, grossular and andraditeEuropean Journal of Mineralogy, Vol. 4, No. 4, pp. 651-664GlobalMineralogy, Garnets
DS1992-0569
1992
Gillet, P.Gillet, P., Fiquet, G., Malezieux, J.M., Geiger, C.A.high pressure and high temperature Raman spectroscopy of end-member garnets-pyrope, grossular and andraditeEuropean Journal of Mineralogy, Vol. 4, No. 4, July-August pp. 651-664GlobalMineralogy, Garnets
DS1993-0121
1993
Gillet, P.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
DS1993-0545
1993
Gillet, P.Gillet, P.Water in the mantle of the earth. (in French)Recherche, (in French), Vol. 24, No. 255, June pp. 676-685MantleComposition
DS1994-1530
1994
Gillet, P.Sautter, V., Gillet, P.Les diamants, messagers de profondeurs de la terre.(in French)La Recherche, (in French), Vol. 25, Dec. 21, pp. 1238-45.GlobalDiamond genesis -overview
DS1995-0636
1995
Gillet, P.Gillet, P.Mineral physics, mantle mineralogy and mantle dynamicsComptes Rendus de'l Academie Des Sciences Serie II , *in Eng., Vol. 320, No. 5, March 2, pp. 341-356.MantleReview -geophysics mantle, Geodynamics
DS1996-0938
1996
Gillet, P.McMillan, P.F., Hemley, R.J., Gillet, P.Vibrational spectroscopy of mantle mineralsIn: Mineral spectroscopy edited by Dyar, pp. 175-214.MantleMineral spectroscopy
DS1998-0511
1998
Gillet, P.Gillet, P., Hemley, R.J., McMillan, P.F.Vibrational properties at high pressures and temperaturesReviews in Mineralogy, Vol. 37, pp. 525-90.MantleMineralogy, Petrology - experimental
DS1998-0680
1998
Gillet, P.Jambon, A., Gillet, P., Chamorro, ColticeHelium and argon poor magmas from the under gassed mantleMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 705-6.Hawaii, Mantlehelium, Geodynamics
DS2002-0105
2002
Gillet, P.Barrat, J.A., Jambon, A., Bohn, M., Gillet, P., Sautter, V., Gopei, C., Lesourd, M.Petrology and chemistry of the picritic shergottite north west AfricaGeochimica et Cosmochimica Acta, Vol.66, 19, pp.3505-18.West AfricaPicrites
DS2002-0572
2002
Gillet, P.Gillet, 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
DS2002-1100
2002
Gillet, P.Mostefaoui, S., El Goresy, A., Hopper, P., Gillet, P., Ott, U.Mode of occurrence , textural settings and nitrogen isotopic compositions of in situEarth and Planetary Science Letters, Vol. 204, No. 1-2, pp. 89-100.GlobalMeteorites - diamonds, geochronology
DS2003-0379
2003
Gillet, P.El Goresy, A., Dubrovinsky, L.S., Gillet, P., Mostefaoul, S., Graup, G.A new natural super hard transparent polymorph of carbon from the Popigai impactComptes Rendus Geosciences, IN FRENCH, Vol. 335, 12, Oct. pp. 889-898.RussiaBlank
DS200412-0515
2003
Gillet, P.El Goresy, A., Dubrovinsky, L.S., Gillet, P., Mostefaoul, S., Graup, G., Drakopoulos, M., Simionovici, A.S.A new natural super hard transparent polymorph of carbon from the Popigai impact crater, Russia.Comptes Rendus Geoscience, Vol. 335, 12, Oct. pp. 889-898.RussiaLonsdaleite, graphite, mineralogy
DS200612-0623
2006
Gillet, P.Ionov, D.A., Hofmann, A.W., Merlet, C., Gurenko, A.A., Hellebrand, E., Montagnac, G., Gillet, P., PrikhodkoDiscovery of whitlockite in mantle xenoliths: inferences for water and halogen poor fluid and trace element residence in the terrestrial upper mantle.Earth and Planetary Science Letters, Vol. 244, 1-2, Apr. 15, pp. 201-207.MantleXenolith - mineralogy
DS200712-0315
2007
Gillet, P.Fiquet, G., Coltice, N.,Guyot, F., Gillet, P.Potassium content in the Earth's core: a high pressure and high temperature study of the Fe K system.Plates, Plumes, and Paradigms, 1p. abstract p. A279..MantleCore, mantle boundary
DS201412-0222
2003
Gillet, P.El Goresy, A., Dubrovinsky, L.S., Gillet, P., Mostefaoui, S., Graup, G., Drakopoulos, M., Simionovici, A.S., Swamy, V., Masaitis, V.L.A new natural, super-hard, transparent polymorph of carbon from the Popigai impact crater, Russia.Comptes Rendus Geoscience, Vol. 335, pp. 889-898.Russia, YakutiaMeteorite
DS201506-0284
2015
Gillet, P.Miyahara, M., Ohtani, E., El Goresy, A., Lin, Y., Feng, L.,Zhang, J-C., Gillet, P., Nagase, T., Muto, J., Nishijima, M.Unique large diamonds in a urelilite from Almahat a Sitta TC3, asteroid.Geochimica et Cosmochimica Acta, Vol. 163, pp. 14-26.TechnologyUrelilite
DS201611-2131
2016
Gillet, P.Piet, H., Badro, J., Nabiei, F., Gillet, P.Spin and valence dependence of iron partitioning in Earth's deep mantle.Proceedings of National Academy of Science USA, Vol. 113, 40, pp. 11127-11130.MantleIron

Abstract: We performed laser-heated diamond anvil cell experiments combined with state-of-the-art electron microanalysis (focused ion beam and aberration-corrected transmission electron microscopy) to study the distribution and valence of iron in Earth’s lower mantle as a function of depth and composition. Our data reconcile the apparently discrepant existing dataset, by clarifying the effects of spin (high/low) and valence (ferrous/ferric) states on iron partitioning in the deep mantle. In aluminum-bearing compositions relevant to Earth’s mantle, iron concentration in silicates drops above 70 GPa before increasing up to 110 GPa with a minimum at 85 GPa; it then dramatically drops in the postperovskite stability field above 116 GPa. This compositional variation should strengthen the lowermost mantle between 1,800 km depth and 2,000 km depth, and weaken it between 2,000 km depth and the D” layer. The succession of layers could dynamically decouple the mantle above 2,000 km from the lowermost mantle, and provide a rheological basis for the stabilization and nonentrainment of large low-shear-velocity provinces below that depth.
DS201701-0026
2016
Gillet, P.Piet, H., Badro, J., Nabiel, F., Dennenwaldt, T., Shim, S-H., Cantoni, M., Hebert, C., Gillet, P.Spin and valence dependence on iron partitioning in Earth's deep mantle.Proceedings of National Academy of Science USA, Vol. 113, no. 40, pp. 11127-11130.MantleUHP

Abstract: We performed laser-heated diamond anvil cell experiments combined with state-of-the-art electron microanalysis (focused ion beam and aberration-corrected transmission electron microscopy) to study the distribution and valence of iron in Earth's lower mantle as a function of depth and composition. Our data reconcile the apparently discrepant existing dataset, by clarifying the effects of spin (high/low) and valence (ferrous/ferric) states on iron partitioning in the deep mantle. In aluminum-bearing compositions relevant to Earth's mantle, iron concentration in silicates drops above 70 GPa before increasing up to 110 GPa with a minimum at 85 GPa; it then dramatically drops in the postperovskite stability field above 116 GPa. This compositional variation should strengthen the lowermost mantle between 1,800 km depth and 2,000 km depth, and weaken it between 2,000 km depth and the D" layer. The succession of layers could dynamically decouple the mantle above 2,000 km from the lowermost mantle, and provide a rheological basis for the stabilization and nonentrainment of large low-shear-velocity provinces below that depth.
DS201804-0686
2018
Gillet, P.Dorfman, S.M., Badro, J., Nabiel, F., Prakapenka, V.B., Cantoni, M., Gillet, P.Carbonate stability in the reduced lower mantle.Earth and Planteray Science Letters, Vol. 489, pp. 84-91.Mantlecarbonate

Abstract: Carbonate minerals are important hosts of carbon in the crust and mantle with a key role in the transport and storage of carbon in Earth's deep interior over the history of the planet. Whether subducted carbonates efficiently melt and break down due to interactions with reduced phases or are preserved to great depths and ultimately reach the core-mantle boundary remains controversial. In this study, experiments in the laser-heated diamond anvil cell (LHDAC) on layered samples of dolomite (Mg,?Ca)CO3 and iron at pressure and temperature conditions reaching those of the deep lower mantle show that carbon-iron redox interactions destabilize the MgCO3 component, producing a mixture of diamond, Fe7C3, and (Mg,?Fe)O. However, CaCO3 is preserved, supporting its relative stability in carbonate-rich lithologies under reducing lower mantle conditions. These results constrain the thermodynamic stability of redox-driven breakdown of carbonates and demonstrate progress towards multiphase mantle petrology in the LHDAC at conditions of the lowermost mantle.
DS201805-0964
2018
Gillet, P.Nabiel, F., Badro, J., Dennenwaldt, T., Oveisi, E., Cantoni, M., Hebert, C., El Goresy, A., Barrat, J-A., Gillet, P.A large planetary body inferred from diamond inclusions in a urelite metorite.Nature Communications, doe:10.1038/ s41467-018- 030808-6 6p. PdfTechnologyureilite

Abstract: Planetary formation models show that terrestrial planets are formed by the accretion of tens of Moon- to Mars-sized planetary embryos through energetic giant impacts. However, relics of these large proto-planets are yet to be found. Ureilites are one of the main families of achondritic meteorites and their parent body is believed to have been catastrophically disrupted by an impact during the first 10 million years of the solar system. Here we studied a section of the Almahata Sitta ureilite using transmission electron microscopy, where large diamonds were formed at high pressure inside the parent body. We discovered chromite, phosphate, and (Fe,Ni)-sulfide inclusions embedded in diamond. The composition and morphology of the inclusions can only be explained if the formation pressure was higher than 20?GPa. Such pressures suggest that the ureilite parent body was a Mercury- to Mars-sized planetary embryo.
DS202009-1624
2020
Gillet, P.Dorfman, S.M., Potapkin, V., Lv, M., Greenberg, E., Kupenko, I., Chumakov, A.I., Bi, W., Alp, E.E., Liu, J., Magrez, A., Dutton, S.E., Cava, R.J., McCammon, C.A., Gillet, P.Effects of composition and pressure on electronic states of iron in bridgmanite.American Mineralogist, Vol. 105, pp. 1030-1039. pdfMantleredox

Abstract: Electronic states of iron in the lower mantle's dominant mineral, (Mg,Fe,Al)(Fe,Al,Si)O3 bridgmanite, control physical properties of the mantle including density, elasticity, and electrical and thermal conductivity. However, the determination of electronic states of iron has been controversial, in part due to different interpretations of Mössbauer spectroscopy results used to identify spin state, valence state, and site occupancy of iron. We applied energy-domain Mössbauer spectroscopy to a set of four bridgmanite samples spanning a wide range of compositions: 10-50% Fe/total cations, 0-25% Al/total cations, 12-100% Fe3+/total Fe. Measurements performed in the diamond-anvil cell at pressures up to 76 GPa below and above the high to low spin transition in Fe3+ provide a Mössbauer reference library for bridgmanite and demonstrate the effects of pressure and composition on electronic states of iron. Results indicate that although the spin transition in Fe3+ in the bridgmanite B-site occurs as predicted, it does not strongly affect the observed quadrupole splitting of 1.4 mm/s, and only decreases center shift for this site to 0 mm/s at ~70 GPa. Thus center shift can easily distinguish Fe3+ from Fe2+ at high pressure, which exhibits two distinct Mössbauer sites with center shift ~1 mm/s and quadrupole splitting 2.4-3.1 and 3.9 mm/s at ~70 GPa. Correct quantification of Fe3+/total Fe in bridgmanite is required to constrain the effects of composition and redox states in experimental measurements of seismic properties of bridgmanite. In Fe-rich, mixed-valence bridgmanite at deep-mantle-relevant pressures, up to ~20% of the Fe may be a Fe2.5+ charge transfer component, which should enhance electrical and thermal conductivity in Fe-rich heterogeneities at the base of Earth's mantle.
DS1998-0512
1998
Gillet, Ph.Gillet, Ph., Matas, Fiquet, Chamorro, Maryinez, JambonVolatiles in the Earth's mantle: insights from mineral and melt physicsMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 521-2.MantleMagnesite, noble gases, volcanism.
DS1994-0705
1994
Gillies, A.D.S.Hancock, G.E., Gillies, A.D.S.Issues in Australasian mining taxation: the arguments for and against resource rent taxationAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 4, July pp. 11, 13-17AustraliaLegal, Mining taxation
DS201609-1706
2016
Gilligan, A.Boyce, A., Bastow, I.D., Darbyshire, F.A., Ellwood, A.G., Gilligan, A., Levin, V., Menke, W.Subduction beneath Laurentia modifies the eastern North American cratonic edge: evidence from P wave and S wave tomography.Journal of Geophysical Research,, Vol. 121, 7, pp. 5013-5030.CanadaSubduction

Abstract: The cratonic cores of the continents are remarkably stable and long-lived features. Their ability to resist destructive tectonic processes is associated with their thick (?250 km), cold, chemically depleted, buoyant lithospheric keels that isolate the cratons from the convecting mantle. The formation mechanism and tectonic stability of cratonic keels remains under debate. To address this issue, we use P wave and S wave relative arrival-time tomography to constrain upper mantle structure beneath southeast Canada and the northeast USA, a region spanning three quarters of Earth's geological history. Our models show three distinct, broad zones: Seismic wave speeds increase systematically from the Phanerozoic coastal domains, through the Proterozoic Grenville Province, and to the Archean Superior craton in central Québec. We also recover the NW-SE trending track of the Great Meteor hot spot that crosscuts the major tectonic domains. The decrease in seismic wave speed from Archean to Proterozoic domains across the Grenville Front is consistent with predictions from models of two-stage keel formation, supporting the idea that keel growth may not have been restricted to Archean times. However, while crustal structure studies suggest that Archean Superior material underlies Grenvillian age rocks up to ?300 km SE of the Grenville Front, our tomographic models show a near-vertical boundary in mantle wave speed directly beneath the Grenville Front. We interpret this as evidence for subduction-driven metasomatic enrichment of the Laurentian cratonic margin, prior to keel stabilization. Variable chemical depletion levels across Archean-Proterozoic boundaries worldwide may thus be better explained by metasomatic enrichment than inherently less depleted Proterozoic composition at formation.
DS201711-2524
2017
Gilligan, A.Liddell, M.V., Bastow, I., Darbyshire, F., Gilligan, A., Pugh, S.The formation of Laurentia: evidence from shear wave splitting.Earth and Planetary Science Letters, Vol. 479, pp. 170-178.Canada, Nunavut, Baffin Islandgeophysics - seismics

Abstract: The northern Hudson Bay region in Canada comprises several Archean cratonic nuclei, assembled by a number of Paleoproterozoic orogenies including the Trans-Hudson Orogen (THO) and the Rinkian-Nagssugtoqidian Orogen. Recent debate has focused on the extent to which these orogens have modern analogues such as the Himalayan-Karakoram-Tibet Orogen. Further, the structure of the lithospheric mantle beneath the Hudson Strait and southern Baffin Island is potentially indicative of Paleoproterozoic underthrusting of the Superior plate beneath the Churchill collage. Also in question is whether the Laurentian cratonic root is stratified, with a fast, depleted, Archean core underlain by a slower, younger, thermally-accreted layer. Plate-scale process that create structures such as these are expected to manifest as measurable fossil seismic anisotropic fabrics. We investigate these problems via shear wave splitting, and present the most comprehensive study to date of mantle seismic anisotropy in northern Laurentia. Strong evidence is presented for multiple layers of anisotropy beneath Archean zones, consistent with the episodic development model of stratified cratonic keels. We also show that southern Baffin Island is underlain by dipping anisotropic fabric, where underthrusting of the Superior plate beneath the Churchill has previously been interpreted. This provides direct evidence of subduction-related deformation at 1.8 Ga, implying that the THO developed with modern plate-tectonic style interactions.
DS201809-2058
2018
Gilligan, A.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.
DS202004-0529
2020
Gilligan, A.Petrescu, L., Bastow, I.D., Darbyshire, F.A., Gilligan, A., Bodin, T., Menke, W., Levin, V.Three billion years of crustal evolution in eastern Canada: constraints from receiver functions.Journal of Geophysical Research: Solid Earth, in press available, 24p. PdfCanadageophysics - seismics

Abstract: The geological record of SE Canada spans more than 2.5Ga, making it a natural laboratory for the study of crustal formation and evolution over time. We estimate the crustal thickness, Poisson's ratio, a proxy for bulk crustal composition, and shear velocity (Vs) structure from receiver functions at a network of seismograph stations recently deployed across the Archean Superior craton, the Proterozoic Grenville and the Phanerozoic Appalachian provinces. The bulk seismic crustal properties and shear velocity structure reveal a correlation with tectonic provinces of different ages: the post-Archean crust becomes thicker, faster, more heterogenous and more compositionally evolved. This secular variation pattern is consistent with a growing consensus that crustal growth efficiency increased at the end of the Archean. A lack of correlation among elevation, Moho topography, and gravity anomalies within the Proterozoic belt is better explained by buoyant mantle support rather than by compositional variations driven by lower crustal metamorphic reactions. A ubiquitous ?20km thick high-Vs lower-crustal layer is imaged beneath the Proterozoic belt. The strong discontinuity at 20km may represent the signature of extensional collapse of an orogenic plateau, accommodated by lateral crustal flow. Wide anorthosite massifs inferred to fractionate from a mafic mantle source are abundant in Proterozoic geology and are underlain by high Vs lower crust and a gradational Moho. Mafic underplating may have provided a source for these intrusions and could have been an important post-Archean process stimulating mafic crustal growth in a vertical sense.
DS1989-1447
1989
Gilligan, J.M.Starling, A., Gilligan, J.M., Carter, A.H.C., Foster, R.P.Experimental evidence for very low solubility of rareearth elements inCO2 rich fluids at mantle conditions #2Nature, Vol.340, No. 6231, July 27, pp. 298-300GlobalRare earth, Mantle
DS1980-0142
1980
Gilligan, L.B.Gilligan, L.B., Lishmund, S.R.Mineral Resources of the Orana RegionNew South Wales Open File., No. GS 1980-098, 15P. UNPUBL.Australia, New South WalesMineral Occurrences, Gemstones, Diamonds
DS1960-0243
1962
Gilliland, W.N.Gilliland, W.N.Possible Continuation of the Mendocino Fracture ZoneScience., Vol. 137, PP. 685-686.GlobalMid-continent
DS200512-0338
2005
Gillin, P.Gillin, P.Nunavut's first diamond mine - the Jericho project.British Columbia & Yukon Mineral Exploration Roundup, Jan.24-27th., p. 84-5.Canada, NunavutNews item - brief overview, Tahera
DS200612-0461
2006
Gillin, P.Gillin, P.Developing Nunavut's first diamond mine. JerichoRoundup 06, Abstract p.74.Canada, NunavutNews item - Tahara
DS1997-0412
1997
Gillin, R.P.Gillin, R.P.Equity risk assessmentInsight Press, CanadaEconomics, Eguity markets
DS1999-0252
1999
Gillin, R.P.Gillin, R.P., Armstrong, J.M.Financing the mining industry: techniques, trends and outlookNorth Atlantic Mineral Symposium, Sept., abstracts pp. 180-82.GlobalEconomics - techniques, brief overview, Financing - not specific to diamonds
DS2001-0382
2001
Gillis, K.M.Gillis, K.M.Nature and origin of the oceanic lithosphere: some insights from past ocean drilling and plans for future.Geoscience Canada, Vol. 28, No. 4, Dec. pp. 163-9.MantleLithological zones - not specific to diamonds
DS1860-0294
1878
Gillmore, P.Gillmore, P.The Diamond Fields. Great Thirst LandLondon:, PP. 444-466.Africa, South AfricaHistory
DS201911-2527
2019
Gilloly, T.Gilloly, T., Coltice, N., Wolf, C.An anticipation experiment for plate tectonics. Boundaries.Tectonics, in press availableMantleplate tectonics

Abstract: Although plate tectonics has pushed the frontiers of geosciences in the past 50 years, it has legitimate limitations and among them we focus on both the absence of dynamics in the theory, and the difficulty of reconstructing tectonics when data is sparse. In this manuscript, we propose an anticipation experiment, proposing a singular outlook on plate tectonics in the digital era. We hypothesize that mantle convection models producing self?consistently plate?like behavior will capture the essence of the self?organisation of plate boundaries. Such models exist today in a preliminary fashion and we use them here to build a database of mid?ocean ridge and trench configurations. To extract knowledge from it we develop a machine learning framework based on Generative Adversarial Networks (GANs) that learns the regularities of the self?organisation in order to fill gaps of observations when working on reconstructing a plate configuration. The user provides the distribution of known ridges and trenches, the location of the region where observations lack, and our digital architecture proposes a horizontal divergence map from which missing plate boundaries are extracted. Our framework is able to prolongate and interpolate plate boundaries within an unresolved region, but fails to retrieve a plate boundary that would be completely contained inside of it. The attempt we make is certainly too early because geodynamic models need improvement and a larger amount of geodynamic model outputs, as independent as possible, is required. However, this work suggests applying such an approach to expand the capabilities of plate tectonics is within reach.
DS1998-0941
1998
Gillou-Frottier, L.Mareschal, J.C., Gillou-Frottier, L., Cheng, L.Z.Heat flow in the Trans Hudson OrogenGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A117. abstract.ManitobaGeothermometry - heat flow, Trans Hudson Orogen
DS2002-0573
2002
Gilman, J.J.Gilman, J.J.Why diamond is very hardPhilosophical Magazine, A., (ingenta 1022994847), Vol.82, 10,pp. 1811-20.GlobalMineralogy
DS1970-0645
1973
Gilmer, T.H.Chase, C.G., Gilmer, T.H.Precambrian Plate Tectonics- the Mid-continent Gravity HighEarth And Planetary Letters, Vol. 21, No. 1, PP. 70-78.GlobalMid-continent
DS200612-0462
2005
Gilmore, E.Gilmore, E., Gleditsch, N.P., Lujala, P., Rod, J.K.Conflict diamonds: a new dataset. Primary deposits have low probability of being the object of conflict.Conflict Management and Peace Science, Vol. 22, 3, pp. 257-272.GlobalLegal - conflict diamonds
DS200612-0463
2005
Gilmore, E.Gilmore, E., Nils, G., Paivi, R.J.Conflict diamonds: a new dataset.Conflict Management and Peace Science , Vol. 22, 3, Fall, pp. 257-272.AfricaConflict diamonds
DS1980-0302
1980
Gilmore, J.L.Sendlein, L.V.A., Gilmore, J.L.Bedrock Topography of Southwest IowaUnited States Geological Survey (USGS) miscellaneous INVEST. MAP, I-1222, 1: 125, 000.GlobalMid-continent
DS1997-0413
1997
Gilmore, T.J.Gilmore, T.J., Clayton, E.A.Mapping the top of the permafrost using direct current resistivity surveyEnvironmental Geology, Vol. 30, No. 1-2, March 1, pp. 29-33GlobalEnvironment, Permafrost, Geophysics
DS1997-0610
1997
GilmourKoeberl, C., Masaitis, V.L., Shafranovsky, GilmourDiamonds from the Popigal impact structure, RussiaGeology, Vol. 25, No. 11, Nov. pp. 967-970.Russia, SiberiaMineralogy impact diamonds, Sample techniques
DS1990-1584
1990
Gilmour, I.Wright, I.P., Gilmour, I.Meteorites: origin of organic materialsNature, Vol. 345, No. 6271, May 10, p. 110GlobalMeteorites, Organics
DS1992-0570
1992
Gilmour, I.Gilmour, I., Russell, S.S., Arden, J.W., Lee, M.R., Franchi, I.A.Terrestrial carbon and nitrogen isotopic ratios from Cretaceous-Tertiary boundary nanodiamondsScience, Vol. 258, December 4, pp. 1624-1626GlobalGeochronology, Nanodiamonds
DS1995-0823
1995
Gilmour, I.Hough, R.M., Gilmour, I., Pillinger, C.T., Arden, H.J.Diamond and silicon carbide in impact melt rock from the Ries impactcrater.Nature, Vol. 378, No. 6552, Nov. 2, pp. 41-44.GlobalDiamond, SIC., Deposit -Ries crater
DS1997-0523
1997
Gilmour, I.Hough, R.M., Gilmour, I., Pillinger, C.T., LangenhorstDiamonds from the iridium rich K-T boundary layer at Arroyo el Mimbral, Tamaulipas, Mexico.Geology, Vol. 25, No. 11, Nov. pp. 1019-22.MexicoK-T boundary, Diamonds - mineralogy, techniques
DS2002-0574
2002
Gilmour, J.Gilmour, J.Partnering for sustainability - an NGO perspectiveAustralian Institute of Mining and Metallurgy, No. 3/2002, pp.185-7.GlobalMining - environmental agreement, socioeconomic
DS200512-0339
2005
Gilmour, J.D.Gilmour, J.D., Verchocsky, A.B., Fisenko, A.V., Holland, G., Turner, G.Xenon isotopes in size separated nanodiamonds from Efremovka: 129 Xe, Xe-P3 and Xe-P6.Geochimica et Cosmochimica Acta, Vol. 69, 16, Aug.15, pp. 4133-4148.TechnologyNanodiamonds, geochronology, degassing events
DS1995-0637
1995
Gilmour, W.R.Gilmour, W.R.Metallic and industrial mineral assessment report on the results for diamond exploration north of Hinton.Alberta Geological Survey, MIN 19950017AlbertaExploration - assessment, Montello Resources Ltd.
DS201312-0311
2013
Gilotti, J.Gilotti, J.Continental crust at mantle depths.Elements, Vol. 9, 4, pp. 255-260.MantleCoesite
DS201312-0349
2013
Gilotti, J.Hacker, B.R., Gerya, T.V., Gilotti, J.Formation and exhumation of ultrahigh pressure terranes.Elements, Vol. 9, 4, pp. 289-293.MantleUHP
DS1992-0571
1992
Gilotti, J.A.Gilotti, J.A., Friderichsen, J.D., Higgins, A.K., Steenfelt, A.A new eclogite province in the Arctic Caledonides, southeast Greenland 77to 78 degGeological Society of America (GSA) Abstract Volume, Vol. 24, No. 3, March p. 23. abstractGreenlandEclogite, Xenoliths
DS1994-0621
1994
Gilotti, J.A.Gilotti, J.A.Eclogites and related high-pressure rocks from north-east GreenlandGronlands Geol. Unders. Rapp., No. 162, pp. 77-90.GreenlandEclogites, Websterite bodies
DS1996-0532
1996
Gilotti, J.A.Gilotti, J.A., Elevold, S.Partial eclogization of igneous protoliths from northeastern Greenland and exlogite province...Geological Society of America, Abstracts, Vol. 28, No. 7, p. A-358.GreenlandEclogites, Caledonides
DS1998-0174
1998
Gilotti, J.A.Brueckner, H.K., Gilotti, J.A., Nutman, A.Caledonian eclogite- facies metamorphism of Early Proterozoic protoliths from northeast Greenland eclogite...Contributions to Mineralogy and Petrology, Vol. 130, No. 2, pp. 103-120.GreenlandEclogite province, Regional geology
DS2000-0267
2000
Gilotti, J.A.Elevevold, S., Gilotti, J.A.Pressure temperature evolution of retrogressed kyanite eclogites Weinschenk Island, Greenland Caledonides.Lithos, Vol. 53, No. 2, Aug. pp.127-48.GreenlandEclogites, metamorphism
DS2002-0575
2002
Gilotti, J.A.Gilotti, J.A., Krogh Ravna, E.J.First evidence for ultrahigh pressure metamorphism in the north east Greenland Caledonides.Geology, Vol. 30,6, June,pp. 551-4.GreenlandEclogite, coesite, pseudomorph, UHP
DS200412-0666
2004
Gilotti, J.A.Gilotti, J.A., Nutman, A.P., Brueckner, H.K.Devonian to Carboniferous in the Greenland Caledonides: U Pb zircon and Sm Nd ages of high pressure and ultrahigh pressure metamContributions to Mineralogy and Petrology, Vol. 148, 2, pp. 215-235.Europe, GreenlandUHP, geochronology
DS200612-0886
2006
Gilotti, J.A.McClelland, W.C., Power, S.E., Gilotti, J.A., Mazdab, F.K., Wopenka, B.U Pb SHRIMP geochronology and trace element geochemistry of coesite bearing zirocons, north east Greenland Caledonides.Geological Society of America, Special Paper, No. 403, pp. 23-44.Europe, GreenlandCoesite
DS1990-0572
1990
Gilruth, P.T.Gilruth, P.T., Hutchinson, C.F.Assessing deforestation in the Guinea Highlands of West Africa using RemotesensingPhotogrammetric Eng. and Remote Sensing, Vol. 56, No. 10, October pp. 1375-1382GuineaRemote sensing, General interest applicat
DS1999-0047
1999
Gilson, E.Bauman, P., Kellett, R., Sharma, A., Gilson, E.Three innovative geophysical techniques for the sterilization of diamond prospects in Alberta.The Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Vol. 92, No. 1028, Mar. p. 95-6, abstractAlbertaGeophysics
DS202108-1279
2021
Gimenez, M.E.Dragone, G.N., Bologna, M.S., Ussami, N., Gimenez, M.E., Alvarez, O., Klinger, F.G.L., Correa-Otto, S.Lithosphere of South American intracratonic basins: electromagnetic and potential field data reveal cratons, terranes, and sutures.Tectonophysics, Vol. 811, 13p. PdfSouth America, Argentinacratons

Abstract: A magnetotelluric survey comprising 18 broadband stations disposed along a 450 km-long profile was carried out at the transition between the Chaco-Paraná (CPB) and the Paraná (PB) intracratonic basins in northeastern Argentina. Three-dimensional inversions of the responses show that the CPB and southern PB lithospheres are resistive (~103 ? m) down to 120 km, but with distinct crustal and upper mantle electrical properties. Also, Bouguer gravity and density anomalies are positive at CPB, whereas they are negative at PB. We associate the CPB lithosphere with the Paleoproterozoic Rio Tebicuary craton and the southern PB lithosphere with an ancient and buried piece of craton, the Southern Paraná craton. Geochemical data of mantle xenoliths from the Cenozoic alkaline/carbonatitic province within the Rio Tebicuary craton suggest a subcontinental lithospheric mantle affected by metasomatic processes, which explains its lower resistivity (reaching values as low as 300 ? m) and higher density (#Mg = 0.87). In contrast, the Southern Paraná craton is more resistive (>103 ? m) and less dense, suggesting a de-hydrated, depleted, and thicker craton. These cratons are separated by a crustal conductor (15 to 20 km depth; 1-10 ? m) that we interpret as a southward continuation of a linear anomaly (Paraná Axial Anomaly) defined in former induction studies within the PB in Brazil. Hence, we redefined the trace of this conductive lineament: instead of bending towards the Torres Syncline, it continues inside the CPB. We propose the lineament to be an Early Neoproterozoic suture zone that controlled the location of maximum subsidence in the intracratonic basins during the Paleozoic. In the Early Cretaceous, the Paraná Axial Anomaly was the site of maximum extrusion and deposition of Serra Geral basalts. This anomaly separates compositionally distinct cratonic lithospheres along its path. Melting of this heterogeneous and enriched mantle created the Paraná igneous province.
DS1983-0255
1983
Ginger, D.Ginger, D.The Kimberlites of the Noenieput District of Northwest Cape Province, South Africa.Bsc. Thesis, University Leeds, UNKNOWN.South AfricaGeochemistry, Geophysics, Kimberlite
DS2002-1439
2002
Gingerich, J.C.Seigel, H.O., Gingerich, J.C., Kostlin, E.O.Explore or acquire? The dilemmaC.i.m. Bulletin, Vol.95,1058,Feb.pp.9.62-GlobalEconomics - ore reserves, exploration, discoveries
DS201906-1299
2019
Gingerich, T.Hagedorn, G., Ross, M., Paulen, R., Smith, R., Neudorf, C., Gingerich, T., Lian, O.Ice-flow and deglacial history of the Laurentide Ice sheet in the southwestern Great Slave Lake area.GAC/MAC annual Meeting, 1p. Abstract p. 102.Canada, Northwest Territoriesgeomorphology

Abstract: Limited field studies and sparse chronological constraints in the southwestern Great Slave Lake area creates uncertainties about the Laurentide Ice Sheet (LIS) flow history and deglacial chronology. Improved understanding of the western LIS ice-margin morphology and retreat history is required to refine larger ice-sheet interpretations and timing for northwest drainage of glacial Lake McConnell. Using new field observations and geochronology we establish ice-flow history and better constrain regional deglaciation. Paleo-ice flow indicators (n = 66) show an oldest southwestern flow (230°), an intermediate northwesterly flow (305°), and a youngest westerly flow (250°). Till samples bulk sediment and matrix properties (n = 160) allowed identification of two till units. A lower grey till sourced mainly from local Paleozoic sediments produced clast fabrics indicating a southwesterly flow direction, overlain by a brown till that contained an increased Canadian Shield content with lodged elongate boulders a-axes and boulder-top striation orientations indicating a west to northwest ice-flow direction. Ice-flow results show a clockwise shift in direction interpreted as evidence for ice-divide migration followed by topographically controlled deglacial westward flow influenced by the Mackenzie River valley. Minimum deglacial timing estimates were constrained through optical dating of fine-sand deposits in a well-developed strandline (n = 2) and seven aeolian dunes; ages range from 9.9 ± 0.6 to 10.8 ± 0.7 ka BP. These ages are from dunes located below glacial Lake McConnell maximum water level and may thus provide new local lake level age constraints. Ice retreat is informed by a newly-mapped segment of the Snake River moraine, which is an understudied feature in the region. New ice-flow history and ice-margin retreat interpretations will be integrated into the larger body of work on the western LIS providing more confident conclusions on ice-sheet evolution and meltwater drainage pathways, specifically in the southwestern Great Slave Lake area.
DS1998-0047
1998
Ginibre, C.Arndt, N., Ginibre, C., Chauvel, Albaraede, CheadleWere komatiites wet?Geology, Vol. 26, No. 8, Aug. pp. 739-42GlobalMelting hydrous mantle, spiniflex textures, Magmatic volatiles
DS2003-0467
2003
Ginnermann, J.Ginnermann, J., Kusaka, K., Harris, J.W.Oriented graphite single crystal inclusions in diamondZeitschrift fur Kristallographie, Vol. 218, 11, pp. 733-739.GlobalDiamond - inclusions
DS200412-0667
2003
Ginnermann, J.Ginnermann, J., Kusaka, K., Harris, J.W.Oriented graphite single crystal inclusions in diamond.Zeitschrift fur Kristallographie, Vol. 218, 11, pp. 733-739.TechnologyDiamond - inclusions
DS1991-0575
1991
Ginsberg, D.W.Ginsberg, D.W., Whiten, W.J.Cluster analysis for mineral processing applicationsInstitute of Mining and Metallurgy, Vol. 100, Sept-Dec. pp. C 139-146GlobalComputer, Program -Cluster analysis
DS1992-0572
1992
Ginsberg, D.W.Ginsberg, D.W., Whiten W.J.Application of clustering in the analysis and control of mineral processingplantsAusIMM Proceedings, Vol. 297, No. 2, October pp. 9-17GlobalMineral processing, Cluster analysis, computers
DS1981-0181
1981
Ginzburg, A.Ginzburg, A., Mooney, W.D., Lutter, W.J., Walter, A.W.Crustal Structure in the Mississippi Embayment: CrossprofileEos, Vol. 62, No. 45, P. 1046. (abstract.).GlobalMid-continent
DS1982-0494
1982
Ginzburg, A.Peters, D., Mooney, W.D., Andrews, M.C., Ginzburg, A.The Deep Crustal Structure of the Northern Mississippi Embayment.Eos, Vol. 63, No. 45, P. 1118. (abstract.).GlobalMid-continent
DS1983-0256
1983
Ginzburg, A.Ginzburg, A., Mooney, W.D., Walter, A.W., Lutter, W.J., Healy, J.Deep Structure of Northern Mississippi EmbaymentAmerican Association of Petroleum Geologists Bulletin., Vol. 67, No. 11, NOVEMBER PP. 2031-3046.GlobalMid Continent
DS1988-0486
1988
Ginzburg, I.V.Morimoto, N., Fabries, J., Ferguson, A.K., Ginzburg, I.V., et al.Nomenclature of pyroxenes. ... new classification and recommendations based on crystal chemistryMineralogy and Petrology, Vol. 39, pp. 55-76. Database # 17362GlobalRock classification, Mineralogy - pyroxenes
DS1988-0362
1988
Ginzburg, L.N.Kogan, B.S., Ginzburg, L.N., Burenkov, E.K.Investigation of the spatial structures of geochemical fields for prospecting purposesInternational Geology Review, Vol. 30, No. 10, October pp. 1141-1146. Database # 1787RussiaComputer, Program -GEOSCAN Geochemistry
DS1989-1555
1989
Gioan, P.Vicat, J-P., Gioan, P., Albouy, Y., Cornacchia, M., Giorgi, L.Evidence of Upper Proterozoic rifts buried under the Phanerozoic of the Zaire basin on the western border of the Congo craton.(in French)Comptes Rendus, (in French), Vol. 309, No. 11, pp. 1207-1214Democratic Republic of CongoTectonics, Craton
DS1991-1080
1991
Gioan, P.Maurin, J-C., Boudzoumou, F., Diama, L-M., Gioan, P., Michard, A.The Proterozoic of west Congolian belt and its foreland in Congo: newC.r. Academy Of Science Paris, Ser. Ii, Vol. 312, No. ser II, pp. 1327-1334Central Africa, CongoGeochronology, Structure
DS200412-0456
2004
Giordano, D.Dingwell, D.B., Courtial, P., Giordano, D., Nichols, A.R.I.Viscosity of peridotite liquid.Earth and Planetary Science Letters, Vol. 226, 1-2, Sept. 30, pp.127-138.MantleGlass transition, calorimetry
DS200412-0457
2004
Giordano, D.Dingwell, D.B., Giordano, D., Courtial, P., Nichols, A.Viscosity of molten peridotite.Lithos, ABSTRACTS only, Vol. 73, p. S26. abstractMantleGeodynamics
DS200612-1187
2006
Giordano, D.Russell, J.K., Giordano, D., Kopylova, M., Moss, S.Transport properties of kimberlite melt.Emplacement Workshop held September, 5p. abstractGlobalMelting - composition
DS200812-0411
2008
Giordano, D.Giordano, D., Russell, J.K., Dingwell, D.B.Viscosity of magmatic liquids: a model.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 123-134.MantleMagmatism
DS200812-0412
2008
Giordano, D.Giordano, D., Russell, J.K., Dingwell, D.B.Viscosity of magmatic liquids: a model.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 123-134.TechnologyMagmatism
DS201610-1863
2016
Giordano, D.Giordano, D., Russell, J.K.The heat capacity of hydrous multicomponent natural melts and glasses.Chemical Geology, In press available 30p.MantleMelting

Abstract: The thermophysical properties of silicate melts and glasses are of fundamental importance for the characterization of the dynamics and energetics of silicate melts on Earth and terrestrial planets. The heat capacity of silicate melts is of particular importance because of its implications for the temperature dependencies of melt enthalpy and entropy and for the potential relationship to melt structure and transport properties. Currently, there are reliable models for predicting the heat capacity of simple and multicomponent silicate glasses (Cpglass) as a function of composition and temperature. Recent differential scanning calorimetry (DSC) measurements of heat capacity for multicomponent silicate liquid (Cpliquid), however, have shown that published models do not accurately reproduce heat capacity measurements on some silicate melts. Here, we have compiled a database of heat capacity values for hydrous and anhydrous multicomponent natural samples. The measurements are on pairs of glasses and melts over the compositional range (wt%) of: SiO2 (44-79), Al2O3 (5-35), TiO2 (0-3), FeOtot (0 ? 11); Na2O + K2O (0-27); CaO + MgO (0-39), H2O (0-6.3) and minor oxides. The compiled data show strong correlations between silica content (XSiO2) and the configurational heat capacity (Cpconfig) defined as Cpliquid ? Cpglass measured across the glass transition temperature (Tg). This correlation is used to establish an empirical model for predicting Cpliquid as a function of melt composition (i.e. SiO2 content) and values of Cpglass measured at the onset of the glass transition: Cpliquid=52.6-55.88XSiO2+CpglassCpliquid=52.6-55.88XSiO2+Cpglass. The model reproduces values of Cpliquid to within an average relative error of ~ 2.4%. Published models for the heat capacities of silicate melts (e.g., Stebbins, 1984; Richet and Bottinga, 1985; Lange and Navrotsky, 1992) applied to the same dataset have average relative errors in excess of 5.5%.
DS201810-2322
2018
Giordano, D.Giordano, D., Russell, J.K.Towards a structural model for the viscosity of geological melts.Earth and Planetary Science Letters, Vol. 501, pp. 202-212.Mantlemelting

Abstract: The viscosity of silicate melts is the most important physical property governing magma transport and eruption dynamics. This macroscopic property is controlled by composition and temperature but ultimately reflects the structural organization of the melt operating at the microscale. At present, there is no explicit relationship connecting viscosity to silicate melt structure and vice versa. Here, we use a single Raman spectroscopic parameter, indicative of melt structure, to accurately forecast the viscosity of natural, multicomponent silicate melts from spectroscopic measurements on glasses preserved on Earth and other planets. The Raman parameter is taken as the ratio of low and high frequency vibrational bands from the silicate glass by employing a green source laser wavelength of 514.5 nm (R514.5). Our model is based on an empirical linkage between R514.5 and coefficients in the Vogel-Fulcher-Tammann function for the temperature dependence of melt viscosity. The calibration of the Raman-based model for melt viscosity is based on 413 high-temperature measurements of viscosity on 23 melt compositions for which published Raman spectra are available. The empirical model obviates the need for chemical measurement of glass compositions, thereby, providing new opportunities for tracking physical and thermochemical properties of melts during igneous processes (e.g., differentiation, mixing, assimilation). Furthermore, our model serves as a milepost for the future use of Raman spectral data for predicting transport (and calorimetric) properties of natural melts at geological conditions (e.g., volatiles and pressure) and production.
DS201812-2811
2018
Giordano, D.Giordano, D., Russell, J.K.Towards a structural model for the viscosity of geological melts.Earth and Planetary Science Letters, Vol. 501, pp. 202-212.Mantlemelting

Abstract: The viscosity of silicate melts is the most important physical property governing magma transport and eruption dynamics. This macroscopic property is controlled by composition and temperature but ultimately reflects the structural organization of the melt operating at the microscale. At present, there is no explicit relationship connecting viscosity to silicate melt structure and vice versa. Here, we use a single Raman spectroscopic parameter, indicative of melt structure, to accurately forecast the viscosity of natural, multicomponent silicate melts from spectroscopic measurements on glasses preserved on Earth and other planets. The Raman parameter is taken as the ratio of low and high frequency vibrational bands from the silicate glass by employing a green source laser wavelength of 514.5 nm (R514.5). Our model is based on an empirical linkage between R514.5 and coefficients in the Vogel-Fulcher-Tammann function for the temperature dependence of melt viscosity. The calibration of the Raman-based model for melt viscosity is based on 413 high-temperature measurements of viscosity on 23 melt compositions for which published Raman spectra are available. The empirical model obviates the need for chemical measurement of glass compositions, thereby, providing new opportunities for tracking physical and thermochemical properties of melts during igneous processes (e.g., differentiation, mixing, assimilation). Furthermore, our model serves as a milepost for the future use of Raman spectral data for predicting transport (and calorimetric) properties of natural melts at geological conditions (e.g., volatiles and pressure) and production.
DS201903-0541
2019
Giordano, D.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian Craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24. doi:10.1016/ j.gr.2018.12.005South America, Brazilcraton

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201905-1074
2019
Giordano, D.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian Craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24.South America, Brazilcraton

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201908-1808
2019
Giordano, D.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24.South America, Braziltectonics

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201312-0172
2013
Giordano, G.Contincelli, S., Avanzinelli, R., Poli, G., Braschi, E., Giordano, G.Shift from lamproite-like to leucitic rocks: Sr-Nd-Pb isotope dat a from the Monte Cimino volcanic complex vs the Vico stratovolcano, central Italy.Chemical Geology, Vol. 353, pp. 246-266.Europe, ItalyLeucites
DS201312-0194
2013
Giordano, G.Conticelli, S., Avanzinelli, R., Poli, G., Braschi, E., Giordano, G.Shift from lamproite-like to leucitic rocks: Sr-Nd-Pb isotope dat a from the Monte Cimino volcanic complex vs the Vico stratovolcano, central Italy.Chemical Geology, Vol. 353, pp. 246-266.Europe, ItalyLamproite
DS201412-0103
2014
Giordano, G.Cashman, K.V., Giordano, G.Calderas and magma reservoirs. ReviewJournal of Volcanology and Geothermal Research, Vol. 288, pp. 28-45.GlobalCalderas - review
DS1989-1555
1989
Giorgi, L.Vicat, J-P., Gioan, P., Albouy, Y., Cornacchia, M., Giorgi, L.Evidence of Upper Proterozoic rifts buried under the Phanerozoic of the Zaire basin on the western border of the Congo craton.(in French)Comptes Rendus, (in French), Vol. 309, No. 11, pp. 1207-1214Democratic Republic of CongoTectonics, Craton
DS200512-0194
2005
Giorgia, D.Cosca, M.A., Giorgia, D., Rumble, D., Liou, J.G.Limiting effect of UHP metamorphism on length scales of oxygen, hydrogen and argon isotope exchange: an example from the Qinglongshan UHP eclogites, Sulu Terrain.International Geology Review, Vol. 47, 7, pp. 716-749.Asia, ChinaUHP
DS2000-0340
2000
Giorgis, D.Giorgis, D., Cosca, M., Li, S.Distribution and significance of extraneous argon in ultra high pressure (UHP) eclogite Sulu Terrain: UV laser ablation analysis.Earth and Planetary Science Letters, Vol.181, No.4, Sept.30, pp.605-15.ChinaEclogites, ultra high pressure (UHP), Dabie Shan
DS200512-0340
2004
Giorgis, S.Giorgis, S., Markley, M., Tikoff, B.Vertical axis rotation of rigid crustal blocks driven by mantle flow.Geological Society of London Special Paper, No. 226, pp. 83-100.MantleTectonics
DS1998-0513
1998
Giorgobiani, T.V.Giorgobiani, T.V., Basheleishvili, ZakariaThe northward drift of the Gondwanian lithospheric plates and geodynamics of formation of Caucasian OrogenJournal of African Earth Sciences, Vol. 27, 1A, p. 88. AbstractGondwana, Europe, RussiaTectonics, Geodynamics
DS1993-1656
1993
Giorgoni, C.Venturelli, G., Salvioli-Mariani, E., Toscani, L., Barbieri, M., Giorgoni, C.Post-magmatic apatite + hematite + carbonate assemblage in the Jumillalamproites. a fluid inclusion and isotope study.Lithos, Vol. 30, pp. 139-150.GlobalLamproites, Geochronology
DS201705-0830
2017
Giovanardi, T.Giovanardi, T., Girardi, V.A.V., Correia, C.T., Sinigoi, S., Tassinari, C.C.G., Mazzucchelli, M.The growth and contamination mechanism of the Cana Brava layered mafic-ultramafic complex: new field and geochemical evidences.Mineralogy and Petrology, in press available 24p.South America, BrazilGeochemistry

Abstract: The Cana Brava complex is the northernmost of three layered complexes outcropping in the Goiás state (central Brasil). New field and geochemical evidences suggest that Cana Brava underwent hyper- to subsolidus deformation during its growth, acquiring a high-temperature foliation that is generally interpreted as the result of a granulite-facies metamorphic event. The increase along the stratigraphy of the incompatible elements abundances (LREE, Rb, Ba) and of the Sr isotopic composition, coupled with a decrease in ?Nd(790), indicate that the complex was contaminated by the embedded xenoliths from the Palmeirópolis Sequence. The geochemical data suggest that the contamination occurred along the entire magma column during the crystallization of the Upper Mafic Zone, with in situ variations determined by the abundance and composition of the xenoliths. These features of the Cana Brava complex point to an extremely similarity with the Lower Sequence of the most known Niquelândia intrusion (the central of the three complexes). This, together with the evidences that the two complexes have the same age (c.a. 790 Ma) and their thickness and units decrease northwards suggests that Cana Brava and Niquelândia are part of a single giant Brasilia body grown through several melt impulses.
DS201903-0541
2019
Giovanardi, T.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian Craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24. doi:10.1016/ j.gr.2018.12.005South America, Brazilcraton

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201904-0740
2019
Giovanardi, T.Giovanardi, T., Girardi, V.A.V., Teixeira, W., Mazzucchelli, M.Mafic dyke swarms at 1882, 535 and 200 Ma in the Carajas region Amazonian Craton: Sr-Nd isotopy, trace element geochemistry and inferences on their origin and geological settings.Journal of South American Earth Sciences, Vol. 92, pp. 197-208.South America, Brazilcraton

Abstract: The Carajás-Rio Maria region, together with the Rio Maria domain of the Central Amazonian province, comprises the eastern margin of the Amazonian Craton with the Neoproterozoic Araguaia belt. This region hosts several basaltic dyke swarms whose UPb baddeleyite ages highlighted three intrusive events at 1882, 535 and 200?Ma. New geochemical and SrNd isotopic data were obtained for the different groups of the Carajás dykes allowing new insights on i) the mantle source composition beneath the Carajás region through time and ii) the geodynamic setting of the intrusive events. The 1882?Ma swarm is coeval to the Uatumã SLIP event which is one of the oldest intraplate events of the proto-Amazonian craton. Trace elements and isotopic values suggest that the dyke parent melt for those dykes have a crustal component derived from a sedimentary source similar to GLOSS (GLObal Subducting Sediment compositions). This is consistent with the emplacement of the dykes in a supra-subduction setting or in a post-collisional setting. Trace and isotopic values of the 535?Ma dyke swarm are consistent with an enriched mantle source from EMII component. These geochemical features suggest an enrichment of the mantle from an oceanic lithosphere poor in sediments, different to that of the 1882?Ma source. The age of this swarm matches magmatic activity during a post-collisional extensive-transtensive event recorded in the marginal Araguaia belt after the amalgamation of the Amazonian Craton to the Western Gondwana during Neoproterozoic. The 200?Ma dyke swarm which is related to the CAMP (Central Atlantic Magmatic Province) and opening of the Atlantic Ocean shows trace element composition similar to Atlantic E-MORB. The coupled isotopic values are consistent with an enriched mantle source with EMII component. These particular geochemical features suggest that the plume activity responsible for the CAMP near the rifting zone has not affected the mantle beneath the Carajás region.
DS201905-1074
2019
Giovanardi, T.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian Craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24.South America, Brazilcraton

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201908-1808
2019
Giovanardi, T.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24.South America, Braziltectonics

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201906-1271
2019
Giovannelli, D.Barry, P.H., de Moor, J.M., Giovannelli, D., Schrenk, M., Hummer, D.R., Lopez, T., Pratt, C.A., Alpizar Segua, Y., Battaglia, A., Beaudry, A., Bini, G., Cascante, M., d'Errico, G., di Carlo, M., Fattorini, D., Fullerton, K., H+Gazel, E., Gonzalez, G., HalForearc carbon sink reduces long term volatile recycling into the mantle.Nature , 588, 7753, p. 487.Mantlecarbon

Abstract: Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth’s surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth’s deep mantle and shallow crustal reservoirs, as well as Earth’s oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth’s deep mantle than previously estimated.
DS202009-1614
2020
Giovannelli., D.Brovarone, A.V., Butch, C.J., Ciappa, A., Cleaves, H.J., Elmaleh, A., Faccenda, M., Feineman, M., Hermann, J., Nestola, F., Cordone, A., Giovannelli., D.Let there be water: how hydration/dehydration reactions accompany key Earth and life processes.American Mineralogist, Vol. 105, pp. 1152-1160. pdfMantlecarbon

Abstract: Water plays a key role in shaping our planet and making life possible. Given the abundance of water on Earth's surface and in its interior, chemical reactions involving water, namely hydration and dehydration reactions, feature prominently in nature and are critical to the complex set of geochemical and biochemical reactions that make our planet unique. This paper highlights some fundamental aspects of hydration and dehydration reactions in the solid Earth, biology, and man-made materials, as well as their connections to carbon cycling on our planet.
DS201712-2725
2017
Giovannini, A.L.Rossoni, M.B., Bastos Neto, A.C., Souza, V.S., Marquea, J.C., Dantas, E., Botelho, N.F., Giovannini, A.L., Pereira, V.P.U-Pb zircon geochronological investigation on the Morro dos Seis Lagos carbonatite complex and associated Nb deposit ( Amazonas, Brazil).Journal of South American Earth Sciences, Vol. 80, pp. 1-17.South America, Brazilcarbonatite

Abstract: We present results of U-Pb dating (by MC-ICP-MS) of zircons from samples that cover all of the known lithotypes in the Seis Lagos Carbonatite Complex and associated lateritic mineralization (the Morro dos Seis Lagos Nb deposit). The host rock (gneiss) yielded an age of 1828 ± 09 Ma interpreted as the crystallization time of this unit. The altered feldspar vein in the same gneiss yielded an age of 1839 ± 29 Ma. Carbonatite samples provided 3 groups of ages. The first group comprises inherited zircons with ages compatible with the gneissic host rock: 1819 ± 10 Ma (superior intercept), 1826 ± 5 Ma (concordant age), and 1812 ± 27 Ma (superior intercept), all from the Orosirian. The second and the third group of ages are from the same carbonatite sample: the superior intercept age of 1525 ± 21 Ma (MSWD ¼ 0.77) and the superior intercept age of 1328 ± 58 Ma (MSWD ¼ 1.4). The mineralogical study indicates that the ~1.3 Ga zircons have affinity with carbonatite. It is, however, a tendence rather than a well-defined result. The data allow state that the age of 1328 ± 58 Ma represents the maximum age of the carbonatite. Without the same certainty, we consider that the data suggest that this age may be the carbonatite age, whose emplacement would have been related to the evolution of the K'Mudku belt. The best age obtained in laterite samples (a superior intercept age of 1828 ± 12 Ma) is considered the age of the main source for the inherited zircons related to the gneissic host rock.
DS202004-0516
2020
Giovannini, A.L.Giovannini, A.L., Mitchell, R.H., Bastos Neto, A.C., Moura, C.A.V., Pereira, V.P., Porto, C.G.Mineralogy and geochemistry of the Morro dos Seis Lagos siderite carbonatite, Amazonas, Brazil.Lithos, vol. 360-361, 105433 20p. PdfSouth America, Brazil, Amazonascarbonatite

Abstract: The Morro dos Seis Lagos niobium rare earth element, Ti-bearing lateritic deposit (Amazonas, Brazil) is derived from a primary siderite carbonatite. The complex is the only example of a Nb deposit in which Nb-rich rutile is the main Nb ore mineral. Apart from the laterites, at the current level of exposure the complex consists only of siderite carbonatite; silicate rocks are absent. Three types of siderite carbonatite are recognized: (1) a brecciated and oxidized core siderite carbonatite consisting of up to 95 vol% siderite together with: hematite; pyrochlore; Nb-brookite; Ti-maghemite; and thorobastnäsite; (2) a REE- and P-rich variety of the core siderite carbonatite consisting of siderite (up to 95 vol%), hematite, minor pyrochlore, monazite and bastnäsite; (3) a border hydrothermal siderite carbonatite with ~70 vol% siderite, barite (~15 vol%), gorceixite (~7 vol%) and minor rhabdophane and pyrochlore. The country rock gneiss in which the carbonatite was emplaced was affected by potassic fenitization, with the formation of phlogopite and orthoclase together with monazite, fluorapatite and bastnäsite. The siderite carbonatites exhibit a wide variation of ?13C (?5.39‰ to ?1.40‰), accompanied by a significant variation in ?18O (17.13‰ to 31.33‰), especially in the REE-rich core siderite carbonatite, and are explained as due to the presence of both H2O and CO2 in the magma. The core siderite carbonatite is the richest in Fe (48.64-70.85 wt% Fe2O3) and the poorest in Ca (up 0.82 wt% CaO) example of a siderite carbonatite yet recognized The ferrocarbonatite has significant contents of Mn, Ba, Th, Pb and LREE, and a very high Nb (up to 7667 ppm) content due to the presence of Nb-brookite. The substitution 3Ti4+ = Fe2+ + 2Nb5+ recognized in Nb-rich brookite explains enrichment of Nb in the core siderite carbonatite and indicates formation in a reducing environment. The high Nb/Ta ratio (1408-11,459) of the carbonatite is compatible with residual liquids derived by fractional crystallization. The 87Sr/86Sr (0.70411-0.70573) and 144Nd/143Nd (0.512663-0.512715) isotopic data suggest the carbonatite is mantle-derived with essentially no crustal contamination and is younger than the maximum age of 1328 ± 58 Ma (UPb in zircon). We suggest that the Morro dos Seis Lagos carbonatite complex represents the upper-most parts of a differentiated carbonatite magmatic system, and that the siderite carbonatite is related to late-magmatic-to-carbo-hydrothermal processes.
DS202107-1099
2021
Giovannini, A.L.Giovannini, A.L., Bastos Neto, A.C., Porto, C.G., Takehara, L., Pereira, V.P., Bidone, M.H.REE mineralization (primary, supergene and sedimentary) associated to the Morro dos Seis Lagos Nb( REE, Ti) deposit (Amazonas, Brazil).Ore Geology Reviews, doi.org/10.1016/ j.oregeorev. 2021.104308 59p. PdfSouth America, BrazilREE

Abstract: In the Morro dos Seis Lagos Nb (Ti, REE) deposit (MSLD), Amazonas state, Brazil, there are four types of REE mineralization: primary, associated to siderite carbonatite; supergene, associated to laterite profile; and sedimentary (detrital and authigenic). The mineralogical and geochemical evolutions of the REE in these domains are integrated into a comprehensible metallogenic model. The main primary ore in the core siderite carbonatite is 52 m thick with 1.47 wt% REE2O3 mainly in monazite-(Ce) and bastnäsite. However, considering the entire section intersected in the core siderite carbonatite, the average grade drops to 0.7 wt% REE2O3 mainly contained in thorbastnasite. In the border siderite carbonatite, the REE mineralization is hydrothermal [rhabdophane-(Ce) and REE-rich gorceixite]. The LREE and phosphates are concentrated at the reworked laterites from where the HREE were leached. With the advance of lateritization, pyrochlore was completely decomposed. The final secondary Ce-pyrochlore was progressively enriched in Ce4+ with loss in REE3+, resulting in the breakdown of the structure and release Ce under strongly oxidizing conditions (high Ce4+/Ce3+) thus forming extremely pure cerianite-(Ce). This mineral occurs intercalated with goethite bands in the lower part of the weathering profile, represented by the brown laterite, and forms intergrowth with hollandite in the manganiferous laterite, formed in a more alkaline environment closer to the water table. The brown laterite has 1.30 wt% REE2O3, the manganese laterite has 1.54 wt% REE2O3, of which 1.42 wt% is Ce2O3. Tectonic and karstic processes over the carbonatite formed several sedimentary basins. In the Esperança Basin, the sedimentary record (233 m thick) shows the whole evolution of the MSLD. The base of the basin (layer 5) is formed by abundant carbonatite fragments, have florencite-(Ce) mineralization with 1.07 wt% REE2O3; layer 4 is formed by carbonatite fragments interbedded with clayey bed; layer 3 is a rhythmite deposited in a lacustrine environment, with clasts of ferruginous materials related to early stages of carbonatite alteration; layer 2 is made up by clays, is rich in organic matter, has authigenic florencite-(Ce), florencite-(La) and base metals. This layer marks the inversion of the relief and the input into the basin of REE leached from the upper laterites, carried by the groundwater flow; layer 1 was formed by the oxidation of the upper part of layer 2. Layers 1 + 2 have 73 m thick and average of 1.72 wt% REE2O3.
DS1982-0616
1982
Gippius, A.A.Vavilov, V.S., Gippius, A.A., Dravin, V.A., Zajeev, A.M., Zakup.Cathodluminescence of Natural Diamond Associated with Implanted Impurities.Soviet Physics of Semi-conductors, Vol. 16, No. 11, PP. 1288-1290.RussiaBlank
DS200612-1164
2006
Giradri, V.A.V.Rivalenti, G., Zanetti, A., Giradri, V.A.V., Mazzucchelli, M., Tassinari, C.G., Bertotto, G.W.The effect of the Fernando de Noronha plume on the mantle lithosphere in north eastern Brazil.Lithos, in press available,South America, BrazilXenoliths, alkali basalts, geochemistry
DS1989-0512
1989
GirardGirard, J-P, Deynoux, M., Nahon, D.Diagenesis of the upper Proterozoic siliciclastic sediments of the Taoudeni basin, West Africa, and relation to diabase emplacementJournal of Sedimentary Petrology, Vol. 59, No. 2, March pp. 233-248. Database # 17951West AfricaProterozoic, Diagenesis
DS2002-0353
2002
Girard, F.Davaille, A., Girard, F., Le Bars, M.How to anchor hotspots in a convecting mantle?Earth and Planetary Science Letters, Vol. 203, 3, pp. 621-34.MantleHot spots, Convection - model
DS202007-1174
2020
Girard, G.Rooney, T., Girard, G., Tappe, S.The impact on mantle olivine resulting from carbonated silicate melt interaction. Allikite Superior cratonContributions to Mineralogy and Petrology, Vol. 175, 15p. Canadaolivine

Abstract: Interactions between carbonated ultramafic silicate magmas and the continental lithospheric mantle results in the formation of dunite—a ubiquitous xenolith type in kimberlites and aillikites. However, whether this process dominantly occurs in the mantle source region or by subsequent interactions between lithospheric mantle fragments and transporting silica-undersaturated magmas during ascent remains debated. Aillikite magmas, which are derived from the fusion of carbonate-phlogopite metasomes under diamond-stability field upper mantle conditions, have a mineralogically more complex source than kimberlites, providing an opportunity to more fully constrain the origin of dunite xenoliths in such deeply sourced carbonated silicate magmas. Here we present a major and trace element study of olivine occurring in xenoliths and as phenocrysts in an aillikite dike located on the southern Superior Craton. We show that olivine within the dunite microxenoliths exhibits extreme enrichment in Al, Cr, Na, and V when compared to equivalent xenoliths carried by kimberlites. We interpret these results as evidence for the presence of carbonate-phlogopite metasomes left residual in the cratonic mantle source during aillikite magma formation. Our results are inconsistent with models of dunite formation through orthopyroxene dissolution upon kimberlite/aillikite magma ascent, supporting an origin for such dunites that is more closely linked to primary melt generation at the base of relatively thick continental lithosphere. Our work demonstrates that it is possible to constrain the precursor composition of cratonic mantle dunite at depth, thereby facilitating the further exploration of how carbonated silicate magmas modify and weaken continental lithospheric roots.
DS201112-0175
2011
Girard, J.Chen, J., Liu, H., Girard, J.Comparative in situ x-ray diffraction study of San Carlos olivine: influence of water on the 410 km seismic velocity jump in Earth's mantle.American Mineralogist, Vol. 96, pp. 697-702.MantleSubduction
DS201602-0205
2015
Girard, J.Girard, J., Amulele, G., Farla, R., Mohiuddin, A., Karato, S-i.Shear deformation of bridgmanite and magnesiowustite aggregates at lower mantle conditions.Science, Vol. 351, 6269, pp. 144-147.MantleRheology

Abstract: Rheological properties of the lower mantle have strong influence on the dynamics and evolution of Earth. By using the improved methods of quantitative deformation experiments at high pressures and temperatures, we deformed a mixture of bridgmanite and magnesiowüstite under the shallow lower mantle conditions. We conducted experiments up to about 100% strain at a strain rate of about 3 × 10(-5) second(-1). We found that bridgmanite is substantially stronger than magnesiowüstite and that magnesiowüstite largely accommodates the strain. Our results suggest that strain weakening and resultant shear localization likely occur in the lower mantle. This would explain the preservation of long-lived geochemical reservoirs and the lack of seismic anisotropy in the majority of the lower mantle except the boundary layers.
DS202002-0208
2020
Girard, J.Mohiuddin, A., Karto, S-i., Girard, J.Slab weakening during the olivine to ringwoodite transition in the mantle.Nature Geoscience, doi: 10.1038/s41561-019-0523Mantlesubduction

Abstract: The strength of subducted slabs in the mantle transition zone influences the style of mantle convection. Intense deformation is observed particularly in relatively old subducted slabs in the deep mantle transition zone. Understanding the cause of this regional and depth variation in slab deformation requires constraint of the rheological properties of deep mantle materials. Here, we report results of in situ deformation experiments during the olivine to ringwoodite phase transformation, from which we infer the deformation process under the conditions of cold slabs deep in the mantle transition zone. We find that newly transformed fine-grained ringwoodite deforms by diffusion creep and that its strength is substantially smaller than that of coarser-grained minerals but increases with time. Scaling analysis, based on a model of transformation kinetics and grain-size evolution during a phase transformation, suggests that a cold slab will be made of a mixture of weak, fine-grained and strong, coarse-grained materials in the deep transition zone, whereas a warm slab remains strong because of its large grain size. We propose that this temperature dependence of grain size may explain extensive deformation of cold slabs in the deep transition zone but limited deformation of relatively warm slabs.
DS202003-0351
2020
Girard, J.Mohiuddin, A., Karato, S., Girard, J.Slab weakening during olivine to ringwoodite transition in the mantle.Nature Geoscience, Vol. 13, pp. 170-174.Mantleolivine

Abstract: The strength of subducted slabs in the mantle transition zone influences the style of mantle convection. Intense deformation is observed particularly in relatively old subducted slabs in the deep mantle transition zone. Understanding the cause of this regional and depth variation in slab deformation requires constraint of the rheological properties of deep mantle materials. Here, we report results of in situ deformation experiments during the olivine to ringwoodite phase transformation, from which we infer the deformation process under the conditions of cold slabs deep in the mantle transition zone. We find that newly transformed fine-grained ringwoodite deforms by diffusion creep and that its strength is substantially smaller than that of coarser-grained minerals but increases with time. Scaling analysis, based on a model of transformation kinetics and grain-size evolution during a phase transformation, suggests that a cold slab will be made of a mixture of weak, fine-grained and strong, coarse-grained materials in the deep transition zone, whereas a warm slab remains strong because of its large grain size. We propose that this temperature dependence of grain size may explain extensive deformation of cold slabs in the deep transition zone but limited deformation of relatively warm slabs.
DS1990-1532
1990
Girard, J.P.Walter, A.V., Flicoteaux, R., Girard, J.P., Loubet, M., Nahon, D.rare earth elements (REE) pattern in apatites from the Juquia carbonatite, BrasilChemical Geology ( Geochem. of the Earth's surface and of min. formation, 2nd., Vol. 84, No. 1-4, July 5, pp. 378-379. AbstractBrazilCarbonatite, Juquia
DS1997-0414
1997
Girard, J.P.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
DS1989-0410
1989
Girard, M.C.Escadafel, R., Girard, M.C., Courault, D.Munsell soil color and soil reflectance in the visible spectral bands ofLand sat Multispectral Scanner and Thematic Mapper dataRemote Sensing of Environment, Vol. 27, No. 1, January pp. 37-46GlobalRemote Sensing, Soils
DS1992-0125
1992
Girard, R.Birkett, T.C., Girard, R., Moorhead, J., Marchilfon, N.Carte geologique de la Province Grenville a l'est de l'axe LouvicourtVald'Or Senneterre.Quebec Department of Mines, MB 92-15, 15p.QuebecMap - geology
DS1992-0573
1992
Girard, R.Girard, R.Spreadsheet routine for the management of structural dat a with amicrocomputerComputers and Geosciences, Vol. 18, No. 1, pp. 29-46GlobalComputer, Program -Spreadsheet routine
DS1993-0546
1993
Girard, R.Girard, R.Petrographie mineralogie et potential diamantifere de l'intrusion ultramafique brechique KNG du Lac KenogamiExploration Diabior Inc., 49p.QuebecExploration - assessment, Jonquiere Township
DS1993-0547
1993
Girard, R.Girard, R.Etude petrographique et mineralogique de l'intersection de kimberlite du forage AI 93-01 Diatac Ress. WilliamsQuebec Department of Mines, GM 52925, 40p.QuebecExploration - assessment, William Ressources
DS1993-0548
1993
Girard, R.Girard, R., Birkett, T., Moorhead, J., Marchildon, N.Geologie de la region de Press ClovaQuebec Department of Mines, MB 93-04, 54p.QuebecGeology
DS1993-0954
1993
Girard, R.Madore, L., Girard, R.Etude petrographique et recommendations de travaux dans le cadre de l'exploracion pour le diamant.. Castignon.La Societe Miniere Ecudor Inc., Ressources KWG Inc., 37p.QuebecExploration - assessment, KWG Resources
DS1993-1069
1993
Girard, R.Moorhead, J., Girard, R., Boudreau, M-A.Circular aeromagnetic anomalies possibly related to kimberlite intrusions in northwest Quebec.Quebec Department of Mines preliminary promotion document, handout at PDA, 25p. 5 p. text and listing of anomalies by locationQuebecGeophysics, Aeromagnetic anomalies
DS1994-0622
1994
Girard, R.Girard, R.Echantillonnage et evaluation des roches sources diamantiferes.(in French)Seventh Colloque Annuel en Ressources Minerales, Universite du Quebec a, p.8-10. abstract in FrenchQuebecSampling
DS1994-0623
1994
Girard, R.Girard, R.Petrographie et mineralogie des intrusions lamprophyriques et des tuffs a lapilli du secteur du lac Hematite, Fosse du Labrador.Gestion STG Inc. et Ressources KWG In., 96p.Quebec, Ungava, LabradorExploration - assessment, KWG Resources Inc.
DS1994-0624
1994
Girard, R.Girard, R.Petrographie et mineralogie des intrusions lamprophyriques et des tufs a lapilli du secteur du lac Hematite, Fosse du Labrador.Gestion STG Inc. et Ressources KWG In., 96p.Quebec, Ungava, LabradorExploration - assessment, KWG Resources Inc.
DS1996-0990
1996
Girard, R.Moorhead, J., Girard, R., Boudreau, M.A.Anomalies aeromagnetic circulars possiblement reliees a des intrusions de kimberlite dans le nord ouest QuebecQuebec Department of Mines, MB 93-49, 23p.Quebec, Ungava, LabradorGeophysics - magnetics
DS2001-0383
2001
Girard, R.Girard, R.Characterisation de l'intrusion kimberlitique du lac Beaver, petrograhie et mineralogieQuebec Ministere des Resources Naturelles, (FRE), ME-08, 82p.QuebecPetrology
DS2003-0468
2003
Girard, R.Girard, R., Moorhead, J., Marchand, P.Kimberlites in Quebec: current statusQuebec Exploration Conference, Nov. 25-27, 1p. abstractQuebecBrief overview
DS2003-0972
2003
Girard, R.Moorhead, J., Beaumier, M., Girard, R., Heaman, L.Distribution, structural controls and ages of kimberlite fields in the Superior Province of8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractQuebecGeochronology, tectonics
DS200412-0668
2003
Girard, R.Girard, R., Moorhead, J., Marchand, P.Kimberlites in Quebec: current status.Quebec Exploration Conference, Nov. 25-27, 1p. abstractCanada, QuebecBrief overview
DS200412-0669
2004
Girard, R.Girard, R., Parent,M., Aubin, A., Belley, J.M., Lalancette, J.Glacial dispersion of lithological indicators in the Otish Mountain area.Quebec Exploration Conference, Canada, Quebec, Otish MountainsGeochemistry, geomorphology
DS200412-1362
2003
Girard, R.Moorhead, J., Beaumier, M., Girard, R., Heaman, L.Distribution, structural controls and ages of kimberlite fields in the Superior Province of Quebec.8 IKC Program, Session 8, POSTER abstractCanada, QuebecDiamond exploration Geochronology, tectonics
DS200412-1499
2004
Girard, R.Parent, M., Beaumier, M., Girard, R., Paradis, S.J.Diamond exploration in the Archean craton of northern Quebec, kimberlite indicator minerals in eskers of the Saindon-Cambrien coQuebec Exploration Conference, MB 2004-02, 15p.Canada, QuebecOverview
DS2002-1399
2002
GirardeauSantos, J.F., Scharer, U., Ibarguchi, J.I.G., GirardeauGenesis of pyroxenite rich peridotite at Cabo Ortegal : geochemical and Pb Sr Nd isotope data.Journal of Petrology, Vol. 43, No. 1, pp. 17-44.SpainPyroxenite, lead, strontium, neodynium, Petrology
DS1989-0137
1989
Girardeau, J.Boillot, G., Feraud, G., Recq, M., Girardeau, J.Undercrusting by serpentinite beneath rifted marginsNature, Vol. 341, October 12, pp. 523-525. Database # 18207SpainTectonics, Mantle
DS2000-0864
2000
Girardeau, J.Scharer, U., Girardeau, J., Cornen, G., Boillot, G.138-121 Ma asthenospheric magmatism prior continental breakup in the North Atlantic geodynamic implications.Earth and Planetary Science Letters, Vol.181, No.4, Sept.30, pp.555-72.GlobalMagmatism, Tectonics - rifting, continental margin
DS2003-1368
2003
GirardiTeixeira, W., Pinese, J.P.P., Iacumin, V.V., Girardi, Piccirillo, Echevests, RibotCalc alkaline and tholeiitic dyke swarms of Tandilia, Rio de la Plat a Craton, Argentina:Precambrian Research, Vol. 119, 1-4, Dec. 20, pp. 329-353.ArgentinaTrans Amazonian Orogeny
DS1996-0533
1996
Girardi, A.Girardi, A., Mazzucchelli, M., Correia, C.T.Petrology and geochemistry of the mafic dyke swarm of the Treinte Y Tresregion, northeast Uruguay.Journal of South American Earth Sciences, Vol. 9, No. 3/4, pp. 243-250.UruguayDike swarm, Petrology
DS201804-0748
2018
Girardi, A.V.Teixeira, W., Hamilton, M.A., Girardi, A.V., Faleiros, F.M.U Pb baddeleyite ages of key dyke swarms in the Amazonian craton ( Carajas/Rio Maria and Rio Apa areas): tectonic implications for events at 1880, 1110 Ma, 535 Ma and 200 Ma.Precambrian Research, in press available 19p.South Americacraton - Amazonian

Abstract: U-Pb baddeleyite ages for key mafic dykes of the Amazonian Craton reveal four significant intraplate episodes that allow connections with global igneous activity through time and supercontinent cycles. The oldest dykes (Carajás-Rio Maria region) are diabases with ages of 1880.2 ± 1.5 Ma and 1884.6 ± 1.6 Ma, respectively, corresponding with the Tucumã swarm which crops out to the west and is age-equivalent. The magmatic activity has a genetic link with the ca. 1.88 Ga Uatumã Silicic Large Igneous Province (SLIP), characterized by felsic plutonic-volcanic rocks. There is an age correlation with LIP events (ca. 1880 Ma) in the Superior, Slave, Indian and other cratons. This magmatism could be derived from significant perturbations of the upper mantle during the partial assembly of Columbia. Gabbronorite of the Rio Perdido Suite (Rio Apa Terrane) crystallized at 1110.7 ± 1.4 Ma, and is identical to that of the Rincón del Tigre-Huanchaca LIP event of the Amazonian Craton. This event was synchronous with the initiation of Keweenawan magmatism of central Laurentia (Midcontinent Rift) and also with coeval units in the Kalahari, Congo and India cratons. The two youngest U-Pb dates (535 and 200 Ma) occur in the Carajás region. Diabase of the Paraupebas swarm yields an age of 535.1 ± 1.1 Ma, which may be correlative with the giant Piranhas swarm located ca. 900 km apart to the west. The Paraupebas swarm is correlative with post-collisional plutonism within the Araguaia marginal belt. Therefore, the Cambrian dykes may reflect reactivation of cooled lithosphere, due to crustal extension/transtension active along the craton’s margin during assembly of West Gondwana. This magmatism is also contemporaneous with the 539-530 Ma Wichita LIP of southern Laurentia. The youngest studied Carajás region dyke was emplaced at ca. 200 Ma, corresponding with 40Ar/39Ar ages for the Periquito dykes west of Carajás and with most K-Ar ages of the giant Cassiporé swarm, located north of the study area. The newly dated ca. 200 Ma dyke fits well into the known, brief span of ages for the CAMP Large Igneous Province event, around the present central and northern Atlantic Ocean.
DS201012-0472
2010
Girardi, J.D.Manthei, C.D., Ducea, M.N., Girardi, J.D., Patchett, P.Isotopic and geochemical evidence for a recent transition in mantle chemistry beneath the western Canadian Cordillera.Journal of Geophysical Research, Vol. 115, B2, B202204.Canada, Alberta, saskatchewan, Northwest TerritoriesGeochemistry
DS201312-0199
2013
Girardi, V.De Min, A., Hendriks, B., Siejko, F., Comin-Chiaramonti, P., Girardi, V., Ruberti, E., Gomes, C.B., Neder, R.D., Pinho, F.C.Age of ultramafic high K rocks from Planalto da Serra ( Mato Grosso, Brazil).Journal of South American Earth Sciences, Vol. 41, pp. 57-64.South America, BrazilGeochronology
DS1980-0326
1980
Girardi, V.A.V.Svisero, D.P., Haralyi, N.L.E., Girardi, V.A.V.Geology of the Limeira 1, Limeira 2 and Indaia Kimberlites, douradoquara Minas Gerais.Anais Do Congresso, 31st., Vol. 3, PP. 1789-1801.BrazilGeology, Geophysics
DS1986-0292
1986
Girardi, V.A.V.Girardi, V.A.V., Rivalent, G., Sinigoli, S.The petrogenesis of the Niquelandia layered basic ultrabasiccomplex, central Goias, BrasilJournal of Petrology, Vol. 27, No. 3, June pp. 715-744BrazilBlank
DS1989-1278
1989
Girardi, V.A.V.Rivalenti, G., Girardi, V.A.V., Coltorti, M., Correira, C.T.Geochemical models for the petrogenesis of komatiites from the Hidrolina greenstone belt, Central Goias, BrasilJournal of Petrology, Vol. 30, No. 1, pp. 175-197BrazilGreenstone belt, Komatiite
DS200612-0301
2006
Girardi, V.A.V.Da Costa, P.C.C., Girardi, V.A.V., Teixeira, W.40 Ar 39Ar and Rb Sr geochronology of the Goias Crixas dike swarm, central Brazil: constraints on the Neoarchean Paleoproterozoic tectonic boundary...International Geology Review, Vol. 48, 6, pp. 547-560.South America, BrazilGeochronology, subcontinental mantle
DS200712-0897
2006
Girardi, V.A.V.Rivalenti, G., Zanetti, A., Girardi, V.A.V., Mazzucchelli, M., Colombo, C.G., Bertotto, G.W.The effect of the Fernando de Noronha plume on the mantle lithosphere in north eastern Brazil.Geochimica et Cosmochimica Acta, In press availableSouth America, BrazilXenolith - alkali basalt
DS200912-0123
2009
Girardi, V.A.V.Comin-Chiaramonti, P., Lucassen, P., Girardi, V.A.V., De Min, A., Gomes, C.B.Lavas and their mantle xenoliths from intracratonic eastern Paraguay( South American Platform) and Andean domain NW Argentina: a comparative review.Mineralogy and Petrology, in press availableSouth America, Paraguay, ArgentinaXenoliths
DS201012-0044
2010
Girardi, V.A.V.Beatriz de Menezes Leal, A., Canabrava Brito, D., Girardi, V.A.V., Correa-Gomes, L.C., Cerqueira Cruz, S., Bastos Leal, L.R.Petrology and geochemistry of the tholeiitic mafic dykes from the Chapada Diamantina, northeastern Sao Francisco Craton, Brazil.International Dyke Conference Held Feb. 6, India, 1p. AbstractSouth America, BrazilGeochemistry
DS201012-0116
2009
Girardi, V.A.V.Comin-Chiaramonti, P., Lucassen, F., Girardi, V.A.V., De Min, A., Gomes, C.B.Lavas and their mantle xenoliths from intracratonic Eastern Paraguay ( South American Platform) and Anean Domain, NW Argentina: a comparative review.Mineralogy and Petrology, Vol. 98, 1-4, pp. 143-165.South America, Paraguay, ArgentinaXenoliths
DS201612-2342
2016
Girardi, V.A.V.Teixeira, W., Girardi, V.A.V., Mazzucchelli, M., Oliveira, E.P., Correa da Costa, P.C.Precambrian dykes in the Sao Francisco craton revisited: geochemical-isotopic signatures and tectonic significance.Acta Geologica Sinica, Vol. 90, July abstract p. 26-27.South America, Brazil, DiamantinaGeochronology
DS201705-0830
2017
Girardi, V.A.V.Giovanardi, T., Girardi, V.A.V., Correia, C.T., Sinigoi, S., Tassinari, C.C.G., Mazzucchelli, M.The growth and contamination mechanism of the Cana Brava layered mafic-ultramafic complex: new field and geochemical evidences.Mineralogy and Petrology, in press available 24p.South America, BrazilGeochemistry

Abstract: The Cana Brava complex is the northernmost of three layered complexes outcropping in the Goiás state (central Brasil). New field and geochemical evidences suggest that Cana Brava underwent hyper- to subsolidus deformation during its growth, acquiring a high-temperature foliation that is generally interpreted as the result of a granulite-facies metamorphic event. The increase along the stratigraphy of the incompatible elements abundances (LREE, Rb, Ba) and of the Sr isotopic composition, coupled with a decrease in ?Nd(790), indicate that the complex was contaminated by the embedded xenoliths from the Palmeirópolis Sequence. The geochemical data suggest that the contamination occurred along the entire magma column during the crystallization of the Upper Mafic Zone, with in situ variations determined by the abundance and composition of the xenoliths. These features of the Cana Brava complex point to an extremely similarity with the Lower Sequence of the most known Niquelândia intrusion (the central of the three complexes). This, together with the evidences that the two complexes have the same age (c.a. 790 Ma) and their thickness and units decrease northwards suggests that Cana Brava and Niquelândia are part of a single giant Brasilia body grown through several melt impulses.
DS201904-0740
2019
Girardi, V.A.V.Giovanardi, T., Girardi, V.A.V., Teixeira, W., Mazzucchelli, M.Mafic dyke swarms at 1882, 535 and 200 Ma in the Carajas region Amazonian Craton: Sr-Nd isotopy, trace element geochemistry and inferences on their origin and geological settings.Journal of South American Earth Sciences, Vol. 92, pp. 197-208.South America, Brazilcraton

Abstract: The Carajás-Rio Maria region, together with the Rio Maria domain of the Central Amazonian province, comprises the eastern margin of the Amazonian Craton with the Neoproterozoic Araguaia belt. This region hosts several basaltic dyke swarms whose UPb baddeleyite ages highlighted three intrusive events at 1882, 535 and 200?Ma. New geochemical and SrNd isotopic data were obtained for the different groups of the Carajás dykes allowing new insights on i) the mantle source composition beneath the Carajás region through time and ii) the geodynamic setting of the intrusive events. The 1882?Ma swarm is coeval to the Uatumã SLIP event which is one of the oldest intraplate events of the proto-Amazonian craton. Trace elements and isotopic values suggest that the dyke parent melt for those dykes have a crustal component derived from a sedimentary source similar to GLOSS (GLObal Subducting Sediment compositions). This is consistent with the emplacement of the dykes in a supra-subduction setting or in a post-collisional setting. Trace and isotopic values of the 535?Ma dyke swarm are consistent with an enriched mantle source from EMII component. These geochemical features suggest an enrichment of the mantle from an oceanic lithosphere poor in sediments, different to that of the 1882?Ma source. The age of this swarm matches magmatic activity during a post-collisional extensive-transtensive event recorded in the marginal Araguaia belt after the amalgamation of the Amazonian Craton to the Western Gondwana during Neoproterozoic. The 200?Ma dyke swarm which is related to the CAMP (Central Atlantic Magmatic Province) and opening of the Atlantic Ocean shows trace element composition similar to Atlantic E-MORB. The coupled isotopic values are consistent with an enriched mantle source with EMII component. These particular geochemical features suggest that the plume activity responsible for the CAMP near the rifting zone has not affected the mantle beneath the Carajás region.
DS201904-0718
1991
Girardi, V.V.Bossi, J., Campal, N., Civetta, L., Demarchi, G., Girardi, V.V., Mazzucchelli, M., Piccirillo, E.M., Rivalenti, G., Sinigol, S., Teixeira, W., Fragoso-Cesar, A.R.Petrological and geochronological aspects of the Precambrian mafic dyke swarm of Uruguay. IN: Eng. Note Date****BOL.IG-USP, Publ.Esp., Vol. 10, pp. 35-42.South America, Uruguaydykes

Abstract: The subparallel maflc dykes of the Aorida-Durazno-S.José region (SW Uruguay) trend N60-80W and vary in thickness from 0.6 to 50 m. They are part of the mafic dyke swarms intrudlng granitic-gnelssic basement that were mappecl by BOSSI et ai. (1989), In an ares approximately 200 km In length and 100 km in bresdth. Plagioclass, augite, subcalclc augite (plgeonite) and opaques are the maln components of the dykes. Orthopyroxene and oIlvine are very rare. Blotite and homblende are secondary minerais. Quartz-feldspar Intergrowths occur In the coarser gralnecl dykes. The characterlstlc textures are subophitic and intersertal.
DS1998-0066
1998
Girardin, N.Babuska, V., Montagner, J.P., Girardin, N.Age dependent large scale fabric of the mantle lithosphere as derived from surface wave velocity...Pure and Applied Geophys., Vol. 151, No. 2-4, Mar. 1, pp. 257-280.MantleGeophysics - seismics, Tectonics
DS201711-2534
2017
Giraud, G.Vidal, O., Rostom, F., Francois, C., Giraud, G.Global trends in metal consumption and supply: the raw material-energy nexus.Elements, Vol. 13, pp. 319-324.Globalresources

Abstract: The consumption of mineral resources and energy has increased exponentially over the last 100 years. Further growth is expected until at least the middle of the 21st century as the demand for minerals is stimulated by the industrialization of poor countries, increasing urbanization, penetration of rapidly evolving high technologies, and the transition to low-carbon energies. In order to meet this demand, more metals will have to be produced by 2050 than over the last 100 years, which raises questions about the sustainability and conditions of supply. The answers to these questions are not only a matter of available reserves. Major effort will be required to develop new approaches and dynamic models to address social, economic, environmental, geological, technological, legal and geopolitical impacts of the need for resources.
DS1975-0083
1975
Girdler, R.W.Girdler, R.W.The Great Negative Bouguer Gravity Anomaly over AfricaEos, Vol. 50, AUGUST PP. 516-519.AfricaGeotectonics, Geophysics
DS1975-0084
1975
Girdler, R.W.Girdler, R.W.The Great Negative Bouger Gravity Anomaly over AfricaEos, Vol. 56, No. 8, PP. 516-519.Africa, South Africa, BotswanaGeophysics
DS1990-0573
1990
Giresse, P.Giresse, P.Paleoclimatic and structural environment at the end of the Cretaceous along the western flank of the Congo Basin, with application of undergroundmicrodiamonds.Journal of African Earth Sciences, Vol. 10, No. 1/2. pp. 399-408GlobalPaleoclimate, alluvials, Microdiamonds
DS2001-0788
2001
GiretMoine, B., Gregoire, Cottin, Sheppard, O'Reilly, GiretVolatile bearing ultramafic to mafic xenoliths from the Kerugelen Archipelago: evidence for carbonatites...Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 25. (abs)Indian Ocean, mantleCarbonatite, Kerugelen Archipelago
DS200412-1349
2004
GiretMoine, 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
DS1985-0070
1985
Giret, A.Bonin, B., Giret, A.Clinopyroxene Compositional Trends in Over saturated and Undersaturated Alkaline Ring Complexes.Journal of African Earth Sciences, Vol. 3, No. 1-2, PP. 175-183.Africa, South AfricaBlank
DS1985-0071
1985
Giret, A.Bonin, B., Giret, A.Contrasting Roles of Rock Forming Minerals in Alkaline Ringcomplexes.Journal of African Earth Sciences, Vol. 3, No. 1-2, PP. 41-49.South Africa, AfricaBlank
DS1985-0235
1985
Giret, A.Giret, A.Alkaline Volcano Plutonic Complexes in Kerguelen Islands, Southern Indian Ocean.Conference Report On The Meeting of The Volcanics Studies Gr, 1P. ABSTRACT.GlobalAlkaline Ring Complexes
DS1989-0847
1989
Giret, A.Lameyre, J., Black, R., Giret, A.Le magmatism alcalin: donnees geologiques sur quelques provinces oceaniques et continentales.(in French)Geological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A49. (abstract.)West Africa, NigeriaAlkaline rocks
DS1994-0182
1994
Giret, A.Bonin, B., Bardintzeff, J-M., Giret, A.The distribution of felsic rocks within the alkaline igneous complexMem. Soc. Geol. France, No. 166, pp. 9-24.GlobalAlkaline rocks
DS1996-0155
1996
Giret, A.Bonin, B., Bardintzeff, J-M., Giret, A.The distribution of felsic rocks within the alkaline igneous centresMem. Soc. Geol. France, Vol. No. 166 pp. 9-24GlobalMagmatic suites, Alkaline rocks
DS1996-0906
1996
Giret, A.Mattielli, N., Weis, D., Giret, A.Kerguelen basic and ultrabasic xenoliths: evidence for hotspot activityLithos, Vol. 37, No. 2/3, April pp. 261-GlobalGeodynamics, Hotspots
DS200412-0437
2004
Giret, A.Delpech, G., Gregoire, M., O'Reilly, S.Y., Cottin, J.Y., Moine, B., Michon, G., Giret, A.Feldspar from carbonate rich silicate metasomatism in the shallow oceanic mantle under Kerguelen Islands ( South Indian Ocean).Lithos, Vol. 75, 1-2, July pp. 209-237.Kerguelen IslandsMetasomatism, trace element fingerprinting, petrogeneti
DS202008-1377
2020
Giri, R.K.Chalapathi Rao, N.V., Giri, R.K., Pandey, A.Kimberlites, lamproites and lamprophyres from the Indian shield: highlights of researches during 2016-2019.Proceedings Natural Science Academy, Vol. 86, 1, pp. 301-311.Indiakimberlite, lamproites

Abstract: Highlights of researches on kimberlites, lamproites and lamprophyres (and their entrained xenoliths) during 2016-2019 from the Indian context are presented. A few previously unknown occurrences have been brought to light, and a wealth of petrological, geochemical and isotopic data on these rocks became available. All these studies provided new insights into the nomenclatural as well as geodynamic aspects such as subduction-tectonics, mantle metasomatism, lithospheric thickness, supercontinent amalgamation, and break-up and nature of the sub-continental lithospheric mantle from the Indian shield.
DS202008-1431
2020
Giri, R.K.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.
DS202009-1618
2020
Giri, R.K.Chalapathi Rao, N.V., Giri, R.K., Sharma, A., Pandey, A.Lamprophyres from the Indian shield: a review of their occurrence, petrology, tectonomagmatic significance and relationship with the kimberlites and related rocks.Episodes, Vol. 43, 1, pp. 231-248.Indialamprophyres

Abstract: Lamprophyres are some of the oldest recognized alkaline rocks and have been studied for almost the last 150 years. Known for hosting economic minerals such as gold, diamond and base metals, they are also significant in our understanding of the deep-mantle processes (viz., mantle metasomatism and mantleplume-lithosphere interactions) as well as large-scale geodynamic processes (viz., subduction-tectonics, supercontinent amalgamation and break-up). The Indian shield is a collage of distinct cratonic blocks margined by the mobile belts and manifested by large igneous provinces (LIPs) such as the Deccan. A plethora of lamprophyres, varying in age from the Archaean to the Eocene, with diverse mineralogical and geochemical compositions, are recorded from the Indian shield and played a key role in clarifying the tectonic processes, especially during the Paleo- and Mesoproterozoic and the Late Cretaceous. A comprehensive review of the occurrence, petrology, geochemistry and origin of the Indian lamprophyres is provided here highlighting their tectonomagmatic significance. The relationship of the lamprophyres to the Kimberlite clan rocks (KCRs), focusing on the Indian examples, is also critically examined.
DS202106-0947
2021
Giri, T.K.Kumar, S., Kumar, D., Sengupta, K., Giri, T.K.Impact of community based business model and competitive advantage on exports: evidence from diamond industry.Competitive Review, Vol. 31, 2, pp. 276-296. pdfGlobalmarkets

Abstract: his study aims to examine the altering paradigms for two specific characteristics of the international diamond industry: community-based business model and competitive advantage and their impact and interaction effect.
DS1996-1349
1996
Girnia, A.V.Solovova, I.P., Girnia, A.V., Ryabchikov, I.D.Inclusions of carbonate and silicate melts in minerals of alkali basaltoids from the East Pamirs.Petrology, Vol. 4, No. 2, pp. 339-363.Russia, PamirAlkalic rocks, Basaltoids -potassic
DS1991-0576
1991
Girnis, A.Girnis, A., Solovova, I., Ryabchikov, I., Kogarko, L.Petrogenesis of Prairie Creek lamproites: constraints from melt inclusion sand high pressure experimentsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, p. 513ArkansasLamproite, Deposit -Prairie Creek
DS1991-1634
1991
Girnis, A.Solovova, I., Girnis, A., Kogarko, L., Ryabchikov, I.A study of Micro inclusions in minerals of Spanish lamproitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, p. 564GlobalLamproite, Melt inclusions
DS1991-1635
1991
Girnis, A.Solovova, I., Girnis, A., Naumov, V., Guzhova, A.Immiscible salt and silicate melts: dat a from Micro inclusions in minerals of alkali basaltsEuropean Current Research Fluid Inclusions, Firenze, Italy April 10-12, Abstracts, ECROFI XI, p. 205RussiaCarbonatite, Fluid inclusions
DS1992-1453
1992
Girnis, A.Solovova, I., Girnis, A., Ryabchikov, D.Fluid regime of highly potassic mafic-ultramafic magmasProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 1, abstract p. 195Arkansas, AustraliaLamproites, Carbon dioxide
DS1995-0441
1995
Girnis, A.Dreibus, G., Brey, G., Girnis, A.The role of carbon dioxide in the generation and emplacement of kimberlitemagmas: new exp. dat a on CO2Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 138-40.GlobalPetrology -experimental -CO2, Kimberlite magmas
DS2003-0158
2003
Girnis, A.Brey, G.P., Bulatov, V., Girnis, A., Harris, J., Stachel, T.Ferropericlase - a lower mantle phase in the upper mantle8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, AbstractGuineaMantle petrology
DS2003-0469
2003
Girnis, A.Girnis, A., Grutter, H.S.Thermobarometry of mantle peridotites: calibration based on experimental and natural8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractGlobalBlank
DS200412-0205
2003
Girnis, A.Brey, G.P., Bulatov, V., Girnis, A., Harris, J., Stachel, T.Ferropericlase - a lower mantle phase in the upper mantle.8 IKC Program, Session 6, AbstractAfrica, GuineaMantle petrology
DS200412-0206
2004
Girnis, A.Brey, G.P., Bulatov, V., Girnis, A., Harris, J.W., Stachel, T.Ferropericlase - a lower mantle phase in the upper mantle.Lithos, Vol. 77, 1-4, Sept. pp. 655-663.South America, BrazilUHP, diamond inclusions, olivine, San Luiz
DS200412-0670
2003
Girnis, A.Girnis, A., Grutter, H.S.Thermobarometry of mantle peridotites: calibration based on experimental and natural data.8 IKC Program, Session 6, POSTER abstractTechnologyMantle petrology
DS200612-0172
2006
Girnis, A.Brey, G., Bulatov, V., Girnis, A.Redox melting and composition of near liquidus melts of C O H bearing peridotite.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleRedox melting
DS200912-0712
2009
Girnis, A.Solovova, I., Girnis, A., Kopylova, M.Fluid and melt inclusions in minerals of West Greenland lamprophyres. Maniitsoq areaalkaline09.narod.ru ENGLISH, May 10, 2p. abstractEurope, GreenlandChemistry
DS201012-0739
2010
Girnis, A.Solovova, I., Girnis, A.Potassium rich carbonatite magma: mechanism of formation and mineralogy as a result of examination melt inclusions (eastern Pamir).International Mineralogical Association meeting August Budapest, abstract p. 577.Russia, PamirCarbonatite
DS1989-1227
1989
Girnis, A.V.Plaksenko, A.N., Girnis, A.V., Bocharov, V.L.Crystallization conditions of the gabbro-norite of the Yelan nickel bearing plutonInternational Geology Review, Vol. 31, No. 5, May pp. 502-505RussiaPseudobrookite-lamproite association
DS1991-0577
1991
Girnis, A.V.Girnis, A.V., Plaksenko, A.N., Ryabchikov, I.D., Suddaby, P.Geochemical features of ultramafic xenoliths from norite intrusions in the Voronezh crystalline massifGeochemistry International, Vol. 28, No. 11, pp. 1-9RussiaGeochemistry, norite, Komatiites
DS1992-0574
1992
Girnis, A.V.Girnis, A.V., Ryabchikov, I.D.Model of samarium-neodymium (Sm-Nd) isotope evolution of a depleted mantleDoklady Academy of Science USSR, Earth Science Section, Vol. 312, No. 1-3, June pp. 243-246RussiaGeochronology, Mantle
DS1992-0575
1992
Girnis, A.V.Girnis, A.V., Solova, I.P., Ryabchikov, I.D., Guzhova, A.V.high pressure experiments on the conditions of generation of the Prairie Creek lamproite magmaGeochemistry International, Vol. 29, No. 4, pp. 94-102ArkansasLamproite, Experimental petrology
DS1992-1211
1992
Girnis, A.V.Plaksenko, A.N., Girnis, A.V., Isaichkin, A.A., Frolov, S.M.A harzburgite xenolith from the Voronezh crystalline massif PrecambriannoritesGeochemistry International, Vol. 29, No. 2, pp. 146-RussiaXenolith, Harzburgite
DS1993-0723
1993
Girnis, A.V.Isaichkin, A.A., Plaksenko, A.N., Girnis, A.V.Petrology of harzburgite xenoliths from Voronezh crystalline massif norite-diorite intrusions.Geochemistry International, Vol. 30, No. 8, pp. 66-76.RussiaXenoliths
DS1995-0231
1995
Girnis, A.V.Bulatov, V.K., Girnis, A.V., Brey, G.P.Anhydrous partial melting of spinel lherzolites from 3.5 to 20 KBAR:composition of partial melts.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 80-82.RussiaLherzolites
DS1995-0638
1995
Girnis, A.V.Girnis, A.V., Brey, G.P., Ryabchikov, I.D.Origin of Group 1a kimberlites: fluid saturated melting experiments at45-55 kbar.Earth and Planetary Science Letters, Vol. 134, No. 3-4, Sept. 1, pp. 283-296.South AfricaKimberlites, Petrochemistry
DS1997-0285
1997
Girnis, A.V.Doroshev, A.M., Brey, G.P., Girnis, A.V., Turkin, A.I.Pyrope - knorringite garnets in the Earth's mantle: experimental in the MgOAl2O3 SiO2 Cr2O3 systemRussian Geology and Geophysics, Vol. 38, No. 2, pp. 559-586.MantleGarnets, Petrochemistry
DS1998-0514
1998
Girnis, A.V.Girnis, A.V., Stachel, T., Brey, G., Harris, J., PhilipInternally consistent geothermobarometers for garnet harzburgites7th International Kimberlite Conference Abstract, pp. 253-5.GlobalGeothermometry, Garnet harzburgite compositions
DS1999-0100
1999
Girnis, A.V.Bulatov, V.K., Girnis, A.V., Brey, G.P.Experimental melting of spinel lherzolites and the problem of the primary magma genesis of oceanic basaltsPetrology, Vol. 7, No. 1, Jan-Feb. pp. 21-31.MantleMagma, Lherzolite - experimental petrology
DS2002-0222
2002
Girnis, A.V.Bulatov, V.K., Girnis, A.V., Brey, G.P.Experimental melting of a modally heterogeneous mantleMineralogy and Petrology, Vol.75,3-4, pp.131-52.MantleMelt
DS2003-0470
2003
Girnis, A.V.Girnis, A.V.Olivine orthopyroxene melt equilibrium as a thermobarometer for mantle derivedPetrology, Vol. 11, 2, pp. 101-113.MantleMagmatism - melting
DS2003-0471
2003
Girnis, A.V.Girnis, A.V.Olivine orthopyroxene melt equilibrium as a thermometer for mantle derived magmasPetrology, Vol. 11, 2, pp. 101-113.MantleMagmatism, geothermometry
DS2003-1311
2003
Girnis, A.V.Solovova, I.P., Girnis, A.V.Extraction of ore components from mafic magmas by immiscible carbonate and saltin Mineral Exploration and Sustainable Development Vol. 1, eds. Eliopoulos et al., Ore forming processes associated with mafic and ultramafic rockseast Greenlandalkaline igneous complex, Verknedunkeldykskii massif, Gardiner massif
DS200412-0671
2003
Girnis, A.V.Girnis, A.V.Olivine orthopyroxene melt equilibrium as a thermobarometer for mantle derived magmas.Petrology, Vol. 11, 2, pp. 101-113.MantleMagmatism - melting
DS200512-0341
2005
Girnis, A.V.Girnis, A.V., Bulatov, V.K., Brey, G.P.Transition from kimberlite to carbonatite melt under mantle parameters: an experimental study.Petrology, Vol. 13, 1, pp. 1-15.Melting - kimberlite/carbonatite
DS200512-1024
2003
Girnis, A.V.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
DS200612-0464
2006
Girnis, A.V.Girnis, A.V., Bulatov, V.K., Lahaye, Y., Brey, G.P.Partitioning of trace elements between carbonate silicate melts and mantle minerals: experiment and petrological consequences.Petrology, Vol. 14, 5, pp. 492-514.MantleMelts
DS200612-0465
2005
Girnis, A.V.Girnis, A.V., Ryabchikov, I.D.Conditions and mechanisms of generation of kimberlite magmas.Geology of Ore Deposits, Vol. 47, 6, pp. 476-487.RussiaMagmatism
DS200612-0739
2006
Girnis, A.V.Kovalenko, V.I., Naumov, V.B., Girnis, A.V., Dorofeeva, V.A., Yarmolyuk, V.V.Composition and chemical structure of oceanic mantle plumes.Petrology, Vol. 14, 5, pp. 452-476.MantleGeochemistry - hot spots
DS200612-1193
2005
Girnis, A.V.Ryabchikov, I.D., Girnis, A.V.Genesis of low calcium kimberlite magmas.Russian Geology and Geophysics, Vol. 46, 12, pp. 1202-1212.MantleMagmatism
DS200612-1334
2005
Girnis, A.V.Solovova, I.P., Girnis, A.V., Kogarko, L.N., Kononkova, N.N., Stoppa, F., Rosaatelli, G.Compositions of magma and carbonate silicate liquid immiscibility in the Vulture alkaline igneous complex, Italy.Lithos, Vol. 85, 1-4, Nov-Dec. pp. 113-128.Europe, ItalyCarbonatite
DS200612-1335
2006
Girnis, A.V.Solovova, I.P., Girnis, A.V., Ryabchikov, I.D., Simakin, S.G.High temperature carbonatite melts and its inter relations with alkaline magmas of the Dundel'dyk complex, southeastern Pamirs.Doklady Earth Sciences, Vol. 410, no. 7 July-August, pp. 1148-51.RussiaCarbonatite
DS200712-0578
2007
Girnis, A.V.Kovalenko, V.I., Naumov, V.B., Girnis, A.V., Dorofeeva, V.A., Yarmoluk, V.V.Average contents of incompatible and volatile components in depleted, oceanic plume, and within plate continental mantle types.Doklady Earth Sciences, Vol. 445, 6, pp. DOI:10.1134/S1028334 X07060116MantleGeochemistry - plumes
DS200812-0139
2007
Girnis, A.V.Brey, G.P., Bulatov, V.K., Girnis, A.V.Geobarometry for peridotites: experiments in simple and natural systems from 6 to 10 GPa.Journal of Petrology, Vol. 49, 1, pp. 3-24.TechnologyGarnet
DS200812-0140
2008
Girnis, A.V.Brey, G.P., Bulatov, V.K., Girnis, A.V.Experimental melting of magnesite bearing peridotite with H2O and F at 6 - 10 GPa, and implications for the genesis of kimberlites.9IKC.com, 3p. extended abstractMantleMelting
DS200812-0141
2008
Girnis, A.V.Brey, G.P., Bulatov, V.K., Girnis, A.V., Lahaye, Y.Experimental melting of carbonated peridotite at 6-10 GPa.Journal of Petrology, Vol. 49, 4, pp. 797-821.MantleMelting
DS200912-0075
2009
Girnis, A.V.Brey, G.P., Bulato, V.K., Girnis, A.V.Influence of water and fluorine on melting of carbonated peridotite at 6 and 10 GPa.Lithos, In press availableMantleMelting
DS200912-0084
2009
Girnis, A.V.Bulatov, V.K., Girnis, A.V., Brey, G.P.Experimental melting of carbonated K rich garnet harzburgite and origin of kimberlite melts.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractTechnologyMelting
DS200912-0252
2009
Girnis, A.V.Girnis, A.V., Bulatov, V.K., Brey, G.P.Influence of melt compositions on Fe, Mn and Ni partitioning between carbonate silicate melts and mantle minerals: experiments and applications.....alkaline09.narod.ru ENGLISH, May 10, 2p. abstractTechnologyGenesis of kimberlites and inclusions in diamonds
DS201012-0409
2009
Girnis, A.V.Kovalenko, V.I., Naumov, V.B., Girnis, A.V., Dorofeeva, V.A., Yarmolyuk, V.V.Average compositions of magmas and mantle sources of Mid-Ocean Ridges and intraplate Oceanic and Continental settings estimated from the dat a of melt inclusionsDeep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., p.35-78,MantleGlasses of basalts
DS201012-0740
2009
Girnis, A.V.Solovova, I.P., Girnis, A.V., Ryabchikov, I.D., Kononkova, N.N.Mechanisms of formation of barium rich phlogopite and strontium rich apatite during the final stages of alkaline magma evolution.Geochemistry International, Vol. 47, 6, June, pp. 578-591.MantleMagmatism
DS201112-0110
2011
Girnis, A.V.Brey, G.P., Bulatov, V.K., Girnis, A.V.Melting of K rich carbonated peridotite at 6 - 10 GPa and the stability of K phases in the upper mantle.Chemical Geology, Vol. 281, 3-4, pp. 333-342.MantleCratonic geothermometry
DS201112-0370
2011
Girnis, A.V.Girnis, A.V.Peridotite melting experiments.Australian Journal of Earth Sciences, in press available 42p.TechnologyPeridotite
DS201112-0371
2011
Girnis, A.V.Girnis, A.V., Bulatov, V.K., Brey, G.P.Formation of primary kimberlite melts - constraints from experiments at 6-12 GPa and variable CO2/H2O.Lithos, In press available, 42p.TechnologyMelting
DS201112-0372
2011
Girnis, A.V.Girnis, A.V., Bulatov, V.K., Brey, G.P.Formation of primary kimberlite melts - constraints from experiments at 6-12 GPa and variable CO2/H2O.Lithos, Vol. 127, 3-4, Dec. pp. 401-413.TechnologyMelting
DS201112-0549
2010
Girnis, A.V.Kovalenko, V.I., Naumov, V.B., Girnis, A.V., Dorofeeva, V.A., Yarmolyuk, V.V.Average composition of basic magmas and mantle sources of island arcs and active continental margins estimated from the dat a on melt inclusions and quenched glassesVladykin, N.V., Deep Seated Magmatism: its sources and plumes, pp. 22-53.MantlePetrology
DS201112-0726
2011
Girnis, A.V.Naumov, V.B., Kovanenko, V.I., Dorofeeva, V.A., Girnis, A.V., Yarmolyuk,V.V.Average compositions of igneous melts from main geodynamic settings according to the investigation of melt inclusions in minerals& quenched glasses of rocks.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 171-204.MantleMelt inclusion database
DS201112-0984
2011
Girnis, A.V.Solovova, I.P., Girnis, A.V., Kogarko, L.N., Kononkova, N.N.Compositions of magmas and carbonate silicate liquid immiscibility in the Vulture alkaline igneous complex, Italy.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 150-170.Europe, ItalyCarbonatite
DS201212-0690
2012
Girnis, A.V.Solovoa, I.P., Girnis, A.V.silicate carbonate liquid immiscibility and crystallization of carbonate and K rich basaltic magma: insights from melt and fluid inclusions.Mineralogical Magazine, Vol. 76, 2, pp. 411-439.MantleCarbonatite, melting
DS201212-0691
2012
Girnis, A.V.Solovova, I.P., Ohnenstetter, D., Girnis, A.V.Melt inclusions in olivine from boninites of New Caledonia: postentrapment melt modification and estimation of primary magma compositions.Petrology, Vol. 20, 6, pp. 529-544.AsiaBoninites
DS201312-0312
2013
Girnis, A.V.Girnis, A.V., Bulatov, V.K., Brey, G.P., Gerdes, A., Hofer, H.E.Trace element partitioning between mantle minerals and silico-carbonate melts at 6-12 Gpa and applications to mantle metasomatism and kimberlite genesis.Lithos, Vol. 160-161, pp. 183-200.MantleKimberlite genesis, melting
DS201312-0868
2012
Girnis, A.V.Solovova, I.P., Girnis, A.V., Kononkova, N.N.Relationships of carbonate and K rich basaltoid magmas: insight from melt and fluid inclusions.Vladykin, N.V. ed. Deep seated magmatism, its sources and plumes, Russian Academy of Sciences, pp. 164-203.MantleMetasomatism
DS201412-0868
2014
Girnis, A.V.Solovova, I.P., Girnis, A.V.Behavior of F and Cl in agpaitic acid melts.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 155-159.TechnologyMelting
DS201509-0386
2015
Girnis, A.V.Brey, G.P., Girnis, A.V., Bulatov, V.K., Hofer, H.E., Gerdes, A., Woodland, A.B.Reduced sediment melting at 7.5-12 Gpa: phase relations, geochemical signals and diamond nucleation.Contributions to Mineralogy and Petrology, Vol. 170, 25p.TechnologyExperimental petrology

Abstract: Melting of carbonated sediment in the presence of graphite or diamond was experimentally investigated at 7.5–12 GPa and 800–1600 °C in a multianvil apparatus. Two starting materials similar to GLOSS of Plank and Langmuir (Chem Geol 145:325–394, 1998) were prepared from oxides, carbonates, hydroxides and graphite. One mixture (Na-gloss) was identical in major element composition to GLOSS, and the other was poorer in Na and richer in K (K-gloss). Both starting mixtures contained ~6 wt% CO2 and 7 wt% H2O and were doped at a ~100 ppm level with a number of trace elements, including REE, LILE and HFSE. The near-solidus mineral assemblage contained a silica polymorph (coesite or stishovite), garnet, kyanite, clinopyroxene, carbonates (aragonite and magnesite-siderite solid solution), zircon, rutile, bearthite and hydrous phases (phengite and lawsonite at <9 GPa and the hydrous aluminosilicates topaz-OH and phase egg at >10 GPa). Hydrous phases disappear at ~900 °C, and carbonates persist up to 1000-1100 °C. At temperatures >1200 °C, the mineral assemblage consists of coesite or stishovite, kyanite and garnet. Clinopyroxene stability depends strongly on the Na content in the starting mixture; it remains in the Na-gloss composition up to 1600 °C at 12 GPa, but was not observed in K-gloss experiments above 1200 °C. The composition of melt or fluid changes gradually with increasing temperature from hydrous carbonate-rich (<10 wt% SiO2) at 800-1000 °C to volatile-rich silicate liquids (up to 40 wt% SiO2) at high temperatures. Trace elements were analyzed in melts and crystalline phases by LA ICP MS. The garnet-melt and clinopyroxene-melt partition coefficients are in general consistent with results from the literature for volatile-free systems and silicocarbonate melts derived by melting carbonated peridotites. Most trace elements are strongly incompatible in kyanite and silica polymorphs (D < 0.01), except for V, Cr and Ni, which are slightly compatible in kyanite (D > 1). Aragonite and Fe-Mg carbonate have very different REE partition coefficients (D Mst-Sd/L ~ 0.01 and D Arg/L ~ 1). Nb, Ta, Zr and Hf are strongly incompatible in both carbonates. The bearthite/melt partition coefficients are very high for LREE (>10) and decrease to ~1 for HREE. All HFSE are strongly incompatible in bearthite. In contrast, Ta, Nb, Zr and Hf are moderately to strongly compatible in ZrSiO4 and TiO2 phases. Based on the obtained partition coefficients, the composition of a mobile phase derived by sediment melting in deep subduction zones was calculated. This phase is strongly enriched in incompatible elements and displays a pronounced negative Ta-Nb anomaly but no Zr-Hf anomaly. Although all experiments were conducted in the diamond stability field, only graphite was observed in low-temperature experiments. Spontaneous diamond nucleation and the complete transformation of graphite to diamond were observed at temperatures above 1200-1300 °C. We speculate that the observed character of graphite-diamond transformation is controlled by relationships between the kinetics of metastable graphite dissolution and diamond nucleation in a hydrous silicocarbonate melt that is oversaturated in C.
DS201805-0945
2018
Girnis, A.V.Girnis, A.V., Brey, G.P., Bulatov, V.K., Hofer, H.E., Woodland, A.B.Graphite to diamond transformation during sediment-peridotite interaction at 7.5 and 10.5 Gpa.Lithos, in press available 42p.Mantleperidotites

Abstract: Diamond nucleation and growth were investigated experimentally at 7.5 and 10.5?GPa and temperatures up to 1500?°C. Samples consisted of two layers: i) H2O- and CO2-bearing model sediment and ii) graphite-bearing garnet harzburgite comprising natural minerals. Two experimental series were conducted, one under a controlled temperature gradient with the sedimentary layer usually in the cold zone and the other under isothermal conditions. In the latter case, diamond seeds were added to the sedimentary mixture. During the experiments, the sedimentary layer partially or completely melted, with the melt percolating and interacting with the adjacent harzburgite. The graphite-to-diamond transition in the peridotite was observed above 1300?°C at 7.5?GPa and 1200?°C at 10.5?GPa in the temperature-gradient experiments, and at temperatures ~100?°C lower in the isothermal experiments with diamond seeds. Newly formed diamond occurs mostly as individual grains up to 10??m in size and is separate from graphite aggregates. In some cases, an association of diamond with magnesite was observed. Diamond nucleation occurs in hydrous and CO2-bearing silicate melt following graphite dissolution and recrystallization. In the case of the diamond-magnesite association, diamond was probably formed through carbonate reduction coupled with graphite oxidation. The composition of the melts ranged from “carbonatitic” with ~10?wt% SiO2 and?>?50?wt% volatiles to hydrous silicate with ~40?wt% SiO2 and?
DS202103-0381
2021
Giro, J.P.Giro, J.P., Almeida, J., Guedes, E., Bruno, H.Tectonic inheritances in rifts: the meaning of NNE lineaments in the continental rift of SE Brazil.Journal of South American Earth Sciences, Vol. 108, 103255. 17p. PdfSouth America, Brazillineaments, tectonics

Abstract: The effect of previous structures inheritance is known to be important in the development of tectonic rifts. A series of overlapping structures generally can be represented by lineaments marking the successive tectonic events. We studied the NNE structural lineaments corridor in the central region of the Ribeira Belt. We used a digital elevation model (DEM) and new and previous fieldwork data to investigate the structural control of such lineaments and their relevance for the Brazilian continental margin. Our results suggest that the NNE direction is a crustal weakness zone characterising corridors of intense ductile and brittle deformation which was recurrently reactivated. Aligned NNE Neoproterozoic-Ordovician ductile and brittle structures as foliations, shear zones, lithological boundaries, and fractures filled by pegmatitic veins coincide with the lineaments. During the Cretaceous rift, a transtensional sinistral regime generated NNE T-fractures filled by mafic dykes. In the Cenozoic, the NNE direction is represented by transfer and domino faults developed within a mega accommodation zone in an intracontinental rift system. Our results suggest that the NNE direction was active in this region throughout the Phanerozoic and has high relevance for the structural development of the continental margin of southeastern Brazil.
DS1960-0827
1967
Girod, M.Girod, M.Donnees Petrographiques sur des Pyroxenolites a Grenat En Enclaves dans des Basaltes du Hoggar ( Sahara Central ).Soc. Franc. Min. Cristall. Bulletin., Vol. 90, PP. 202-213.GlobalBlank
DS2000-0898
2000
Giroola, H.Simmons, N.A., Giroola, H.Multiple seismic discontinuities near the base of the transition zone in the Earth's mantle.Nature, Vol. 405, No. 6786, June 1, pp. 559-61.MantleGeophysics - seismics, Discontinuity
DS1999-0768
1999
Giroux, J.F.Veillette, J.J., Giroux, J.F.The enigmatic rings of the James Bay Lowland, Ontario and Quebec: aprobable geological origin.Geological Survey of Canada (GSC), Open file 3708 $ 12.00Ontario, QuebecStructure, Rings
DS201706-1075
2017
Giruts, M.V.Gordadze, G.N., Kerimov, V.Yu., Gaiduk, A.V., Giruts, M.V., Lobusev, M.A., Serov, S.G., Kuznetsov, N.B., Romanyuk, T.V.Hydrocarbon biomarkers and diamondoid hydrocarbons from Late Precambrian and Lower Cambrian rocks of the Katanga Saddle ( Siberian Platform).Geochemistry International, Vol. 55, 4, pp. 360-366.Russia, Siberiadiamondoid

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.
DS1997-0415
1997
GIS ProceedingsGIS ProceedingsExpanding boundaries: geoscience information for earth system scienceGis Proceedings 32 Annual, Vol. 27, approx. $ 40.00GlobalBook - table of contents, Geoscience information
DS200512-0862
2005
Gisbert, P.E.Pla Cid, J., Stoll Nardi, L.V., Gisbert, P.E., Merlet, C., Boyer, B.SIMS analyses on trace and rare earth elements in coexisting clinopyroxene and mica from minette mafic enclaves in potassic syenites crystallized under high pressure.Contributions to Mineralogy and Petrology, Vol. 148, 6, pp. 675-688.UHP - minettes
DS201312-0634
2013
Gisbert, P.E.Nardi, L.V.S., Pla Cid, J., Pla Cid, C.C., Gisbert, P.E., Balzaretti, N.M.Granite compositions in a veined flower mantle, as indicated by mineral inclusions in diamonds from Juin a deposits, Brazil.Goldschmidt 2013, AbstractSouth America, BrazilDeposit - Juina
DS201412-0691
2014
Gisbert, P.E.Pla Cid, J., Nardi, L.V.S., Pla Cid, C., Gisbert, P.E., Balzaretti, N.M.Acid composition in a veined lower mantle, as indicated by inclusions of ( K, Na) - hollandite + SiO2 in diamonds.Lithos, Vol. 196-197, pp. 42-53.South America, BrazilDeposit - Juina area
DS201412-0692
2014
Gisbert, P.E.Pla Cid, J., Nardi, L.V.S., Pla Cid, C., Gisbert, P.E., Balzaretti, N.M.Acid compositions in a veined lower mantle, as indicated by inclusions of ( K, Na)- Hollandite + SiO2 in diamonds.Lithos, Vol. 196-197, pp. 42-53.South America, BrazilDeposit - Juina
DS2002-0576
2002
Gislason, S.R.Gislason, S.R., Oelkers, E.H., Bruno, J.Geochemistry of crustal fluids: an Andalusian perspectiveChemical Geology, Vol. 190, 1-4, pp.MantleGeochemistry
DS202007-1158
2020
GITLeelawatanasuk, T., Atichat, W., Pisutha-Arnond, V., Sutthirat, C., Jakkawanvibul, J., GITTwo decades of GIT's ruby and sapphire color standards.incolorMagazine.com, Vol. winter pp. 96-103.Asia, Thailandsapphire colour
DS2002-0577
2002
Gitelson, A.A.Gitelson, A.A., Stark, R., Grits, U., et al.Vegetation and soil lines in visible spectral space: a concept and technique for remote estimation of vegetation fraction.International Journal of Remote Sensing, Vol.23,No.13, July 20, pp. 2537-62.GlobalRemote sensing - not specific to diamonds, Techniques
DS1960-0666
1966
Gittins, J.Gittins, J.Summaries and Bibliographies of Carbonatite ComplexesInterscience Publishing, PP. 417-540.United States, Gulf Coast, Arkansas, Rocky Mountains, Montana, ColoradoBibliography
DS1970-0087
1970
Gittins, J.Gittins, J.Carbonatites- Nature and OriginReprint of A Paper., 14P.Canada, Tanzania, Russia, South Africa, Sweden, East AfricaOverview, Classification, Geophysics
DS1970-0693
1973
Gittins, J.Gittins, J., Hewins, R.H., Laurin, A.F.Kimberlitic Carbonatitic Dikes of the Saguenay River ValleyProceedings of First International Kimberlite Conference, EXTENDED ABSTRACT PP. 127-130.Canada, QuebecOccurrences
DS1970-0898
1974
Gittins, J.Cooper, A.F., Gittins, J.Shortite in Kimberlite from the Upper Canada Gold Mine, Ontario: Discussion.Journal of GEOLOGY, Vol. 82, No. 5, PP. 667-669.Canada, OntarioBlank
DS1975-0085
1975
Gittins, J.Gittins, J., Hewins, R.H., Laurin, A.F.Kimberlitic and Carbonatitic Dykes of the Saguenay River Valley, Quebec, Canada.Physics and Chemistry of the Earth., Vol. 9, PP. 137-148.Canada, QuebecRelated Rocks, Carbonatite, Kimberlite, Arvida
DS1975-0748
1978
Gittins, J.Gittins, J.Some Observations on the Present State of Carbonatite StudieI Symposio International De Carbonatitos, Pocos De Caldas, Brasil, PP. 107-115.GlobalGeochronology, Mineral Composition, Mineral Chemistry
DS1975-1034
1979
Gittins, J.Gittins, J.Problems Inherent in the Application of Calcite-dolomite Geothermometry to Carbonatites.Contributions to Mineralogy and Petrology, Vol. 69, PP. 1-4.GlobalGenesis
DS1980-0143
1980
Gittins, J.Gittins, J., Fawcett, J.J., Brooks, C.K., Rucklidge, J.C.Intergrowths of Nepheline Potassium Feldspar and Kalsilite Potassium Feldspar: a Re-examination of the Pseudo-leucite Problem.Contributions to Mineralogy and Petrology, Vol. 73, PP. 119-126.Greenland, BatbjergRelated Rocks, Leucite, Mineral Chemistry
DS1981-0102
1981
Gittins, J.Brooks, C.K., Fawcett, J.J., Gittins, J., Rucklidge, J.C.The Batbjerb Complex, East Greenland: a Unique Ultrapotassic Caledonian Intrusion.Canadian Journal of Earth Sciences, Vol. 18, No. 2, PP. 274-285.GreenlandLeucite
DS1985-0688
1985
Gittins, J.Twyman, J.D., Gittins, J.Alkalic Carbonatite Magmas: Parental or Derivative? #2Conference Report of A Meeting of The Volcanics Studies Grou, 1P. ABSTRACT.TanzaniaOldoinyo Lengai
DS1986-0161
1986
Gittins, J.Currie, K.L., Eby, G.N., Gittins, J.The petrology of the Mont Saint Hilaire complex, southernQuebec: an alkaline gabbro peralkaline syenite associationLithos, Vol. 19, No. 1, pp. 65-81QuebecAlkaline rocks
DS1986-0293
1986
Gittins, J.Gittins, J.Genesis and evolution of carbonatite magmasGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 73. (abstract.)GlobalCarbonatite
DS1987-0754
1987
Gittins, J.Twyman, J.D., Gittins, J.Alkalic carbonatite magmas: parental or derivative? #1in: Fitton and Upton, Alkaline igneous rocks, Blackwell publ, pp. 85-94GlobalBlank
DS1988-0256
1988
Gittins, J.Gittins, J.Comment on 'Ra-Th disequilibration temperatures systematics: timescale of carbonatite magma formation at Oldoinyo Langai volcano, TanzaniaGeochimica et Cosmochimica Acta, Vol. 52, p. 957TanzaniaBlank
DS1989-0513
1989
Gittins, J.Gittins, J.Carbonatite origin and diversity. Reply to commentsNature, Vol. 338, No. 6216, p. 548GlobalCarbonatite
DS1989-0514
1989
Gittins, J.Gittins, J.The origin and evolution of carbonatite magmasCarbonatites -Genesis and Evolution, Ed. K. Bell Unwin Hyman Publ, pp. 580-600GlobalCarbonatite-genesis, Magma evolution
DS1989-0515
1989
Gittins, J.Gittins, J., Jago, B.C.Calcitic carbonatite lavas reinterpreted; their significance for magmagenesisNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 108. AbstractGlobalCarbonatite
DS1989-0788
1989
Gittins, J.Kjarsgaard, B., Hamilton, D.L., Gittins, J.Carbonatite origin and diversity.. discussion and replyNature, Vol. 338, No. 6216, April 13, pp. 547-548GlobalCarbonatite, Genesis
DS1990-0574
1990
Gittins, J.Gittins, J., Beckett, M.F., Jago, B.C.Composition of the fluid phase accompanying carbonatite magma: a criticalexaminationAmerican Mineralogist, Vol. 75, No. 9-10. Sept.-Oct. pp. 1106-1109QuebecOka, Husereau Hill, Carbonatite
DS1990-0575
1990
Gittins, J.Gittins, J., Jago, B.C.Carbonatite lavas: the role of fluorine, chlorine and water in carbonatitemagmasTerra, Abstracts of Experimental mineralogy, petrology and, Vol. 2, December abstracts p. 76GlobalCarbonatite, Experimental petrology
DS1990-0751
1990
Gittins, J.Jago, B.C., Gittins, J.Comparative roles of fluorine and water in carbonatite magma evolutionTerra, Abstracts of Experimental mineralogy, petrology and, Vol. 2, December abstracts p. 82GlobalExperimental Petrology, Carbonatite
DS1991-0578
1991
Gittins, J.Gittins, J., Jago, B.C.Extrusive carbonatites: their origins reappraised in the light of new experimental dataGeological Magazine, Vol. 128, No. 4, July pp. 301-305GlobalExperimental petrology, Carbonatite
DS1991-0782
1991
Gittins, J.Jago, B.C., Gittins, J.The role of fluorine in the crystallization of niobium and phosphorous ores in carbonatitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 193-195GlobalPyrochlore, apatite, Experimental petrology
DS1991-0783
1991
Gittins, J.Jago, B.C., Gittins, J.The role of fluorine in carbonatite magma evolutionNature, Vol. 349, No. 6304, January 3, pp. 56-58TanzaniaCarbonatite, Oldoinyo Lengai -fluorine
DS1992-0576
1992
Gittins, J.Gittins, J., Beckett, M.F., Jago, B.C.Composition of the fluid phase accompanying carbonatite magmas: acritical examination- replyAmerican Mineralogist, Vol. 77, No. 5, 6, May-June pp. 666-667GlobalCarbonatite, Petrology
DS1992-0577
1992
Gittins, J.Gittins, J., Jago, B.C.The role of fluorine in the crystallization and evolution of carbonatitemagmasEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.349GlobalCarbonatite, Fluorine
DS1993-0734
1993
Gittins, J.Jago, B.C., Gittins, J.Pyrochlore crystallization in carbonatites: the role of fluorineSouth African Journal of Geology, Vol. 96, No. 3, Sept. pp. 149-159.TanzaniaCarbonatite -pyrochlore, Petrology -experimental
DS1994-0823
1994
Gittins, J.Jago, B.C., Gittins, J.Solubility of water in carbonatite magmas and partitioning of Fluorine and Chlorine between magma and aequeous fluid.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.GlobalCarbonatite, Petrology -experimental
DS1995-0639
1995
Gittins, J.Gittins, J., Harmer, R.E.The origin of periclase bearing carbonatitesGeological Society Africa 10th. Conference Oct. Nairobi, p. 112-3. AbstractTanzaniaCarbonatite -periclase, Deposit -Kerimasi
DS1995-0640
1995
Gittins, J.Gittins, J., Harmer, R.E.Evolutionary paths of carbonatite magmasGeological Society Africa 10th. Conference Oct. Nairobi, p. 111-2. AbstractTanzaniaCarbonatite, Calcite or dolomite Carbonatite
DS1995-0751
1995
Gittins, J.Harmer, R.E., Gittins, J.Carbonatites: primary or secondary magma types?Geological Society Africa 10th. Conference Oct. Nairobi, p. 110. AbstractSouth Africa, TanzaniaCarbonatite
DS1997-0416
1997
Gittins, J.Gittins, J.Discussion on carbonatites: where do we go from here?Geological Association of Canada (GAC) Abstracts, GlobalCarbonatite
DS1997-0417
1997
Gittins, J.Gittins, J., Harmer, R.E.What is a ferrocarbonatite? A revised classificationJournal of African Earth Sciences, Vol. 25, No. 1, July pp. 159-GlobalCarbonatite, Ferrocarbonatite - definition
DS1997-0418
1997
Gittins, J.Gittins, J., Harmer, R.E.Dawson Oldoinyo Lengai calciocarbonatite - a magmatic sovite or an extremely altered natrocarbonatite.Mineralogical Magazine, Vol. 61, No. 3, June pp. 351-355.TanzaniaCarbonatite
DS1997-0476
1997
Gittins, J.Harmer, R.E., Gittins, J.Dolomitic carbonatite parental magmasGeological Association of Canada (GAC) Abstracts, GlobalCarbonatite, Magma - genesis
DS1997-0477
1997
Gittins, J.Harmer, R.E., Gittins, J.The origin of dolomitic carbonatites: field and experimental constraintsJournal of African Earth Sciences, Vol. 25, No. 1, July pp. 5-28.South AfricaCarbonatite
DS1998-0515
1998
Gittins, J.Gittins, J., Jago, B.C.Differentiation of natrocarbonatite magma at Oldoinyo Lengai volcano, Tanzania.Mineralogical Magazine, Vol. 62, No. 6, Dec. 1, pp. 759-68.TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS1998-0583
1998
Gittins, J.Harmer, R.E., Gittins, J.The case for primary, mantle derived carbonatite magmaJournal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 1895-04.AfricaCarbonatite, Napak, Kerimasi, Shombole, Dorova, Shawa, Magmatism, Spiskop
DS1999-0331
1999
Gittins, J.Jago, B.C., Gittins, J.Manganese and Fluorine bearing rasvumite in natrocarbonatite at Oldoinyo Lengai Tanzania.Mineralogical Magazine, Vol. 63, No. 1, pp. 53-5.TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS2000-0390
2000
Gittins, J.Harmer, R.E., Hayward, G., Siegfried, P., Gittins, J.The geology and economic potential of the Xiluvo carbonatite complex, Mozambique.Igc 30th. Brasil, Aug. abstract only 1p.GlobalCarbonatite, Deposit - Xiluvo
DS2001-0384
2001
Gittins, J.Gittins, J., Harmer, R.E.The carbonatite alkalic silicate igneous rock association: an unfortunate and misleading assumption.Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 16 (abs)Zimbabwe, South AfricaCarbonatite, Genesis
DS200512-0342
2003
Gittins, J.Gittins, J., Harmer, R.E.Myth and reality in the carbonatite silicate rock association.Periodico di Mineralogia, Vol. LXX11, 1. April, pp. 19-26.Field relations, geochronology
DS200512-0343
2005
Gittins, J.Gittins, J., Harmer, R.E., Barker, D.S.The bimodal composition of carbonatites: reality or misconception?Lithos, Advanced in press,Carbonatite, mineralogy
DS200612-0466
2005
Gittins, J.Gittins, J., Harmer, R.E., Barker, D.S.The bimodal composition of carbonatites: reality or misconception?Lithos, Vol. 85, 1-4, Nov-Dec. pp. 129-139.Carbonatite, genesis
DS201607-1318
2016
Gittins, J.Viladkar, S.G., Gittins, J.Trace element and REE geochemistry of Siriwasan carbonatite, Chhota Udaipur, Gujarat.Journal of the Geological Society of India, Vol. 87, 6, pp. 709-715.IndiaCarbonatite

Abstract: The Siriwasan carbonatite-sill along with associated alkaline rocks and fenites is located about 10 km north of the well-known Amba Dongar carbonatite-alkaline rocks diatreme, in the Chhota Udaipur carbonatite-alkaline province. Carbonatite has intruded as a sill into the Bagh sandstone and overlying Deccan basalt. This resulted in the formation of carbonatite breccia with enclosed fragments of basement metamorphics, sandstone and fenites in the matrix of ankeritic carbonatite. The most significant are the plugs of sovite with varied mineralogy that include pyroxene, amphibole, apatite, pyrochlore, perovskite and sphene. REE in sovites is related to the content of pyrochlore, perovskite and apatite. The carbon and oxygen isotopic compositions of some sovite samples and an ankeritic carbonatite plot in the "mantle box" pointing to their mantle origin. However, there is also evidence for mixing of the erupting carbonatite magma with the overlying Bagh limestone. The carbonatites of Siriwasan and Amba Dongar have the same Sr and Nd isotopic ratios and radiometric age, suggesting the same magma source. On the basis of available chemical analyses this paper is aimed to give some details of the Siriwasan carbonatites. The carbonatite complex has good potential for an economic mineral deposit but this is the most neglected carbonatite of the Chhota Udaipur province.
DS1960-0828
1967
Gittins, J.G.Gittins, J.G., Macintyre, R.M., Yorck, D.The Ages of Carbonatite Complexes in Eastern CanadaCanadian Journal of Earth Sciences, Vol. 4, PP. 651-655.Canada, QuebecRelated Rocks
DS2001-1289
2001
GittsovichZaitseva, T.S., Goncharov, G.N., Gittsovich, SemenovCrystal chemistry of chromium spinel from Imandra Layered pluton, Kola PeninsulaGeochemistry International, Vol. 39, No. 5, pp. 479-81.Russia, Kola PeninsulaSpinels
DS202008-1383
2020
Giuiani, A.Dalton, H., Giuiani, A., Phillips, D., Hergt, J., Maas, R., Woodhead, J., Matchan, E., O'Brien, H.Kimberlite magmatism in Finland: distinct sources and links to the breakup of Rodinia.Goldschmidt 2020, 1p. AbstractEurope, Finlanddeposit - Kuusamo

Abstract: The Karelian Craton in Finland is host to (at least) two distinct pulses of kimberlite magmatism. Twenty kimberlite occurrences have so far been discovered on the southwest margin of the craton at Kaavi-Kuopio and seven kimberlites are located in the Kuusamo area within the core of the craton. Comprehensive radiometric age determinations (U-Pb, Ar- Ar and Rb-Sr) reveal that all kimberlite activity was restricted to the Proterozoic. The Kaavi-Kuopio field was emplaced over a protracted period from ~610 to 550 Ma and is predated by the Kuusamo cluster that represents a relatively short pulse of magmatism at ~750 to 730 Ma. The emplacement of kimberlites globally has recently been linked to supercontinent reorganisation and we propose a similar scenario for these Finnish occurrences which, at the time of kimberlite emplacement, were situated on the Baltica paleo-continent. This land mass was contiguous with Laurentia in the Proterozoic and together formed part of Rodinia. The breakup of Rodinia is considered to have commenced at ~750 Ma and initiation of the opening of the Iapetus ocean at ~615 Ma. Contemporaneous with Kaavi-Kuopio magmatism, this latter period of Neoproterozoic crustal extension also includes the emplacement of kimberlites and related rocks in areas that were linked with Baltica as part of Rodinia - West Greenland and eastern North America. Both the initial and final periods of Rodinia’s breakup have been linked to mantle upwellings from the core-mantle boundary. We suggest that kimberlite magmatism in Finland was promoted by the influx of heat from mantle upwellings and lithospheric extension associated with the demise of Rodinia. Although both magmatic episodes are potentially linked to the breakup of Rodinia, whole-rock and perovskite radiogenic isotope compositions for the Kuusamo kimberlites (?Nd(i) +2.6 to +3.3, ?Hf(i) +3.1 to +5.6) are distinct from the Kaavi-Kuopio kimberlites (?Nd(i) -0.7 to +1.8, ?Hf(i) -6.1 to +5.2). The spread in Hf isotope compositions for the Kaavi-Kuopio magmas may be linked to variable assimilation of diverse mantle lithologies.
DS202003-0341
2019
Giuilani, G.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.
DS201608-1418
2016
Giuillong, M.Kueter, N., Soesilo, J., Fedortchouk, Y., Nestola, F., Belluco, L., Troch, J., Walle, M., Giuillong, M., Von Quadt, A., Driesner, T.Tracing the depositional history of Kalimantan diamonds by zircon provenance and diamond morphology studies. ( kimberlite or lamproite)Lithos, in press availableIndonesia, BorneoDeposit - Kalimantan

Abstract: Diamonds in alluvial deposits in Southeast Asia are not accompanied by indicator minerals suggesting primary kimberlite or lamproite sources. The Meratus Mountains in Southeast Borneo (Province Kalimantan Selatan, Indonesia) provide the largest known deposit of these so-called “headless” diamond deposits. Proposals for the origin of Kalimantan diamonds include the adjacent Meratus ophiolite complex, ultra-high pressure (UHP) metamorphic terranes, obducted subcontinental lithospheric mantle and undiscovered kimberlite-type sources. Here we report results from detailed sediment provenance analysis of diamond-bearing Quaternary river channel material and from representative outcrops of the oldest known formations within the Alino Group, including the diamond-bearing Campanian-Maastrichtian Manunggul Formation. Optical examination of surfaces of diamonds collected from artisanal miners in the Meratus area (247 stones) and in West Borneo (Sanggau Area, Province Kalimantan Barat;
DS201212-0243
2012
Giulani, A.Giulani, A., Kamenetsky, V.S., Phillips, D., Wyatt, B.A., Hutchinson, G.Alkali-carbonate fluids in the lithospheric mantle.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractMantleCarbonatite
DS201912-2807
2019
Giulani, A.Mitchell, R.H., Giulani, A., O'Brien, H.What is a kimberlite? Petrology and mineralogy of hypabyssal kimberlite.Elements, Vol. 15, 6, pp.Mantlediamond genesis

Abstract: Hypabyssal kimberlites are subvolcanic intrusive rocks crystallised from mantle-derived magmas poor in SiO2 and rich in CO2 and H2O. They are complex, hybrid rocks containing significant amounts of mantle-derived fragments, primarily olivine with rare diamonds, set in a matrix of essentially magmatic origin. Unambiguous identification of kimberlites requires careful petrographic examination combined with mineral compositional analyses. Melt inclusion studies have shown that kimberlite melts contain higher alkali concentrations than previously thought but have not clarified the ultimate origin of these melts. Because of the hybrid nature of kimberlites and their common hydrothermal alteration by fluids of controversial origin (magmatic and/or crustal), the composition of primary kimberlite melts remains unknown.
DS201812-2856
2019
Giuli, G.Nazzarini, S., Nestola, F., Zanon, V., Bindi, L., Scricciolo, E., Petrelli, M., Zanatta, M., Mariotto, G., Giuli, G.Discovery of moissanite in a peralkaline syenite from the Azores Islands.Lithos, Vol. 324-325, pp. 68-73.Europe, Portugal, Azoresmoissanite

Abstract: Our discovery of moissanite grains in a peralkaline syenite from the Água de Pau Volcano (São Miguel, Azores Islands, Portugal) represents the first report of this mineral in present day oceanic geodynamic settings. Raman spectroscopy and single-crystal X-ray diffraction show the presence of both the 6H and 4H polytypes with the predominance of the first one. The distribution of trace elements is homogeneous, except for Al and V. Azorean moissanite often hosts rounded inclusions of metallic Si and other not yet identified metallic alloys. A process involving a flushing of CH4-H2 ultra-reducing fluids in the alkaline melts might be considered as a possible mechanism leading to the formation of natural SiC, thus calling for strongly reducing conditions that were locally met in the crust-mantle beneath the São Miguel Island.
DS201902-0302
2019
Giuli, G.Nazzarini, S., Nestola, F.,Zanon, V., Bindi, L., Giuli, G.Discovery of moissanite in a peralkaline syenite from the Azores Islands.Lithos, Vol. 324, pp. 68-73.Europe, Portugal, Azoresmoissanite

Abstract: Our discovery of moissanite grains in a peralkaline syenite from the Água de Pau Volcano (São Miguel, Azores Islands, Portugal) represents the first report of this mineral in present day oceanic geodynamic settings. Raman spectroscopy and single-crystal X-ray diffraction show the presence of both the 6H and 4H polytypes with the predominance of the first one. The distribution of trace elements is homogeneous, except for Al and V. Azorean moissanite often hosts rounded inclusions of metallic Si and other not yet identified metallic alloys. A process involving a flushing of CH4-H2 ultra-reducing fluids in the alkaline melts might be considered as a possible mechanism leading to the formation of natural SiC, thus calling for strongly reducing conditions that were locally met in the crust-mantle beneath the São Miguel Island.
DS202007-1178
2020
GiulianiSoltys, A., Giuliani, A,m Phillips, D., Kamenetsky, V.S.Kimberlite metasomatism of the lithosphere and the evolution of olivine in carbonate rich melts evidence from the Kimberley kimberlites ( South Africa).Journal of Petrology, 10.1093/petrology /egaa062/5857610 90p. PdfAfrica, South Africadeposit - Kimberley

Abstract: Olivine is the most abundant phase in kimberlites and is stable throughout most of the crystallisation sequence, thus providing an extensive record of kimberlite petrogenesis. To better constrain the composition, evolution, and source of kimberlites we present a detailed petrographic and geochemical study of olivine from multiple dyke, sill, and root zone kimberlites in the Kimberley cluster (South Africa). Olivine grains in these kimberlites are zoned, with a central core, a rim overgrowth, and occasionally an external rind. Additional ‘internal’ and ‘transitional’ zones may occur between the core and rim, and some samples of root zone kimberlites contain a late generation of high-Mg olivine in cross-cutting veins. Olivine records widespread pre-ascent (proto-)kimberlite metasomatism in the mantle including: (a) Relatively Fe-rich (Mg# <89) olivine cores interpreted to derive from the disaggregation of kimberlite-related megacrysts (20% of cores); (b) Mg-Ca-rich olivine cores (Mg# >89; >0.05?wt.% CaO) suggested to be sourced from neoblasts in sheared peridotites (25% of cores); (c) transitional zones between cores and rims probably formed by partial re-equilibration of xenocrysts (now cores) with a previous pulse of kimberlite melt (i.e., compositionally heterogeneous xenocrysts); and (d) olivine from the Wesselton water tunnel sills, internal zones (I), and low-Mg# rims, that crystallised from a kimberlite melt that underwent olivine fractionation within the shallow lithospheric mantle. Magmatic crystallisation begins with internal olivine zones (II), which are common but not ubiquitous in the Kimberley olivine. These zones are euhedral, contain rare inclusions of chromite, and have a higher Mg# (90.0 ± 0.5), NiO, and Cr2O3 contents, but are depleted in CaO compared to the rims. Internal olivine zones (II) are interpreted to crystallise from a primitive kimberlite melt during its ascent and transport of olivine toward the surface. Their compositions suggest assimilation of peridotitic material (particularly orthopyroxene) and potentially sulfides prior to or during crystallisation. Comparison of internal zones (II) with liquidus olivine from other mantle-derived carbonate-bearing magmas (i.e., orangeites, ultramafic lamprophyres, melilitites) show that low (100×) Mn/Fe (?1.2), very low Ca/Fe (?0.6), and moderate Ni/Mg ratios (?1.1) appear to be the hallmarks of olivine in melts derived from carbonate-bearing garnet-peridotite sources. Olivine rims display features indicative of magmatic crystallisation, which are typical of olivine rims in kimberlites worldwide - i.e. primary inclusions of chromite, Mg-ilmenite and rutile, homogeneous Mg# (88.8 ± 0.3), decreasing Ni and Cr, increasing Ca and Mn. Rinds and high-Mg olivine are characterised by extreme Mg-Ca-Mn enrichment and Ni depletion, and textural relationships indicate these zones represent replacement of pre-existing olivine, with some new crystallisation of rinds. These zones likely precipitated from evolved, oxidised, and relatively low-temperature kimberlite fluids after crustal emplacement. In summary, this study demonstrates the utility of combined petrography and olivine geochemistry to trace the evolution of kimberlite magmatic systems from early metasomatism of the lithospheric mantle by (proto-)kimberlite melts, to crystallisation at different depths en route to surface, and finally late-stage deuteric/hydrothermal fluid alteration processes after crustal emplacement.
DS201212-0244
2012
Giuliani, A.Giuliani, A., Kamenetsky, V.S., Kendrick, M.A., Phillips, D., Goemann, K.Nickel rich metasomatism of the lithospheric mantle by pre-kimberlitic alkali S Cl rich C-O-H fluids.Contributions to Mineralogy and Petrology, in press availableAfrica, South AfricaDeposit - Bultfontein
DS201212-0245
2012
Giuliani, A.Giuliani, A., Kamenetsky, V.S., Phillips, D., Kendrick, M.A., Wyatt, B.A., Goemann, K.Nature of alkali-carbonate fluids in the sub-continental lithospheric mantle.Geology, Vol. 40, 11, pp. 967-970.Mantle, RussiaDeposit - Udachnaya
DS201212-0246
2012
Giuliani, A.Giuliani, A.,Kamenetsky, V.S., Lendrick, M.A., Phillips, D., Goemann, K.Nickel-rich metasomatism of the lithospheric mantle by pre-kimberlitic alkali-S-Cl-rich C-O-H fluids.Contributions to Mineralogy and Petrology, in press available 17p.MantleMetasomatism
DS201312-0313
2013
Giuliani, A.Giuliani, A., Kamenetsky, V.S., Kendrick, M.A., Phillips, D., Wyatt, B.A., Maas, R.Oxide, sulphide and carbonate minerals in a mantle polymict breccia: metasomatism by proto-kimberlite magmas, and relationship to the kimberlite megacrystic suite.Chemical Geology, Vol. 353, pp. 4-18.Africa, South AfricaKimberley district
DS201312-0314
2013
Giuliani, A.Giuliani, A., Phillips, D., Kendrick, M.K., Maas, R., Greig, A., Armstrong, R., Felgate, M.R., Kamenetsky, V.S.Dating mantle metasomatism: a new tool ( U/PB LIMA Titanate) and an imposter ( 40Ar/39Ar phlogopite).Goldschmidt 2013, AbstractMantleMetasomatism
DS201412-0293
2014
Giuliani, A.Giuliani, A., Phillips, D., Kamenetsky, V.S., Fiorentini, M.L., Farqukar, J., Kendrick, M.A.Stable isotope ( C,O,S) compositions of volatile rich minerals in kimberlites: a review.Chemical Geology, Vol. 374-375, pp. 61-83.Africa, South Africa, Canada, Northwest Territories, RussiaDeposit - Kimberley, Lac de Gras, Udachnaya
DS201412-0294
2014
Giuliani, A.Giuliani, A., Phillips, D., Kamenetsky, V.S., Kendrick, M.A., Wyatt, B.A., Goemann, K., Hutchinson, G.Petrogenesis of mantle polymict breccias: insights into mantle processes coeval with kimberlite magmatism.Journal of Petrology, Vol. 55, 4, pp. 831-858.Africa, South AfricaDeposit - Bultfontein
DS201412-0438
2014
Giuliani, A.Kamenetsky, V.S., Belousova, E.A., Giuliani, A., Kamenetsky, M.B., Goemann, K., Griffin, W.L.Chemical abrasion of zircon and ilmenite megacrysts in the Monastery kimberlite: implications for the composition of kimberlite melts.Chemical Geology, Vol. 383, pp. 76-85.Africa, South AfricaDeposit - Monastery
DS201412-0439
2014
Giuliani, A.Kamenetsky, V.S., Golovin, A.V., Maas, R., Giuliani, A., Kamenetsky, M.B., Weiss, Y.Towards a new model for kimberlite petrogenesis: evidence from unaltered kimberlites and mantle minerals. Earth Science Reviews, Vol. 139, pp. 145-151.Russia, YakutiaDeposit - Udachnaya
DS201509-0405
2015
Giuliani, A.Kamenetsky, V.S., Mitchell, R.H., Maas, R., Giuliani, A., Gaboury, D., Zhitova, L.Chlorine in mantle derived carbonatite melts revealed by halite in the St. Honore intrusion ( Quebec, Canada).Geology, Vol. 43, 8, pp. 687-690.Canada, QuebecCarbonatite

Abstract: Mantle-derived carbonatites are igneous rocks dominated by carbonate minerals. Intrusive carbonatites typically contain calcite and, less commonly, dolomite and siderite as the only carbonate minerals. In contrast, lavas erupted by the only active carbonatite volcano on Earth, Oldoinyo Lengai, Tanzania, are enriched in Na-rich carbonate phenocrysts (nyerereite and gregoryite) and Na-K halides in the groundmass. The apparent paradox between the compositions of intrusive and extrusive carbonatites has not been satisfactorily resolved. This study records the fortuitous preservation of halite in the intrusive dolomitic carbonatite of the St.-Honoré carbonatite complex (Québec, Canada), more than 490 m below the present surface. Halite occurs intergrown with, and included in, magmatic minerals typical of intrusive carbonatites; i.e., dolomite, calcite, apatite, rare earth element fluorocarbonates, pyrochlore, fluorite, and phlogopite. Halite is also a major daughter phase of melt inclusions hosted in early magmatic minerals, apatite and pyrochlore. The carbon isotope composition of dolomite (?13C = –5.2‰) and Sr-Nd isotope compositions of individual minerals (87Sr/86Sri = 0.70287 in apatite, to 0.70443 in halite; ?Nd = +3.2 to +4.0) indicate a mantle origin for the St.-Honoré carbonatite parental melt. More radiogenic Sr compositions of dolomite and dolomite-hosted halite and heavy oxygen isotope composition of dolomite (?18O = +23‰) suggest their formation at some time after magma emplacement by recrystallization of original magmatic components in the presence of ambient fluids. Our observations indicate that water-soluble chloride minerals, common in the modern natrocarbonatite lavas, can be significant but ephemeral components of intrusive carbonatite complexes. We therefore infer that the parental magmas that produce primary carbonatite melts might be enriched in Na and Cl. This conclusion affects existing models for mantle source compositions, melting scenarios, temperature, rheological properties, and crystallization path of carbonatite melts.
DS201601-0018
2016
Giuliani, A.Giuliani, A., Phillips, D., Kamenetsky, V.S., Goemann, K.Constraints on kimberlite ascent mechanisms revealed by phlogopite compositions in kimberlites and mantle xenoliths.Lithos, Vol. 240, pp. 189-201.Africa, South AfricaDeposit - Bultfontein

Abstract: Kimberlite magmas are of economic and scientific importance because they represent the major host to diamonds and are probably the deepest magmas from continental regions. In addition, kimberlite magmas transport abundant mantle and crustal xenoliths, thus providing fundamental information on the composition of the sub-continental lithosphere. Despite their importance, the composition and ascent mechanism(s) of kimberlite melts remain poorly constrained. Phlogopite is one of the few minerals that preserves a history of fluid migration and magmatism in the mantle and crust and is therefore an invaluable petrogenetic indicator of kimberlite magma evolution. Here we present major and trace element compositional data for phlogopite from the Bultfontein kimberlite (Kimberley, South Africa; i.e. the kimberlite type-locality) and from entrained mantle xenoliths. Phlogopite macrocrysts (~ > 0.3-0.5 mm) and microcrysts (between ~ 0.1 and 0.3 mm) in the Bultfontein kimberlite display concentric compositional zoning patterns. The cores of these phlogopite grains exhibit compositions typical of phlogopite contained in peridotite mantle xenoliths. However, the rims of some grains show compositions analogous to kimberlite groundmass phlogopite (i.e. high Ti, Al and Ba; low Cr), whereas other rims and intermediate zones (between cores and rims) exhibit unusually elevated Cr and lower Al and Ba concentrations. The latter compositions are indistinguishable from matrix phlogopite in polymict breccia xenoliths (considered to represent failed kimberlite intrusions) and from Ti-rich overgrowth rims on phlogopite in other mantle xenoliths. Consequently, it is likely that these phlogopite grains crystallized from kimberlite melts and that the high Ti-Cr zones originated from earlier kimberlite melts at mantle depths. We postulate that successive pulses of ascending kimberlite magma progressively metasomatised the conduit along which later kimberlite pulses ascended, producing progressively decreasing interaction with the surrounding mantle rocks. In our view, these processes represent the fundamental mechanism of kimberlite magma ascent. Our study also indicates that, in addition to xenoliths/xenocrysts and magmatic phases, kimberlite rocks incorporate material crystallized at various mantle depths by previous kimberlite intrusions (mantle-derived ‘antecrysts’).
DS201606-1119
2016
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D., Kamenetsky, V.S., Maas, R., Woodhead, J., Rodemann, T.In-situ assimilation of mantle minerals by kimberlitic magmas - direct evidence from a garnet wehrlite xenolith entrained in the Bultfontein kimberlite ( Kimberley, South Africa).Lithos, Vol. 256-257, pp. 182-196.Africa, South AfricaDeposit - Bultfontein

Abstract: The lack of consensus on the possible range of initial kimberlite melt compositions and their evolution as they ascend through and interact with mantle and crustal wall rocks, hampers a complete understanding of kimberlite petrogenesis. Attempts to resolve these issues are complicated by the fact that kimberlite rocks are mixtures of magmatic, xenocrystic and antecrystic components and, hence, are not directly representative of their parental melt composition. Furthermore, there is a lack of direct evidence of the assimilation processes that may characterise kimberlitic melts during ascent, which makes understanding their melt evolution difficult. In this contribution we provide novel constraints on the interaction between precursor kimberlite melts and lithospheric mantle wall rocks. We present detailed textural and geochemical data for a carbonate-rich vein assemblage that traverses a garnet wehrlite xenolith [equilibrated at ~ 1060 °C and 43 kbar (~ 140-145 km)] from the Bultfontein kimberlite (Kimberley, South Africa). This vein assemblage is dominated by Ca-Mg carbonates, with subordinate oxide minerals, olivine, sulphides, and apatite. Vein phases have highly variable compositions indicating formation under disequilibrium conditions. Primary inclusions in the vein minerals and secondary inclusion trails in host wehrlite minerals contain abundant alkali-bearing phases (e.g., Na-K bearing carbonates, Mg-freudenbergite, Na-bearing apatite and phlogopite). The Sr-isotope composition of vein carbonates overlaps those of groundmass calcite from the Bultfontein kimberlite, as well as perovskite from the other kimberlites in the Kimberley area. Clinopyroxene and garnet in the host wehrlite are resorbed and have Si-rich reaction mantles where in contact with the carbonate-rich veins. Within some veins, the carbonates occur as droplet-like, globular segregations, separated from a similarly shaped Si-rich phase by a thin meniscus of Mg-magnetite. These textures are interpreted to represent immiscibility between carbonate and silicate melts. The preservation of reaction mantles, immiscibility textures and disequilibrium in the vein assemblage, suggests quenching, probably triggered by entrainment and rapid transport toward the Earth's surface in the host kimberlite magma. Based on the Sr-isotope systematics of vein carbonate minerals, and the close temporal relationship between carbonate-rich metasomatism and kimberlite magmatism, we suggest that the carbonate-rich vein assemblage was produced by the interaction between a melt genetically related to the Bultfontein kimberlite and wehrlitic mantle wall rock. If correct, this unique xenolith sample provides a rare snapshot of the assimilation processes that might characterise parental kimberlite melts during their ascent through the lithospheric mantle.
DS201610-1838
2016
Giuliani, A.Abersteiner, A., Giuliani, A., Kamenetsky, V.S., Phillips, D.Petrographic and melt inclusion constraints on the petrogenesis of a magmaclast from the Venetia kimberlite cluster, South Africa.Chemical Geology, in press available 11p.Africa, South AfricaDeposit - Venetia

Abstract: Kimberlitic magmaclasts are discrete ovoid magmatic fragments that formed prior to emplacement from disrupted kimberlite magma. To provide new constraints on the origin and evolution of the kimberlite melts, we document the mineralogy and petrography of a magmaclast recovered from one of the ca. 520 Ma Venetia kimberlites, South Africa. The sample (BI9883) has a sub-spherical shape and consists of a ~ 10 mm diameter central olivine macrocryst, surrounded by porphyritic kimberlite. The kimberlitic material consists of concentrically aligned, altered olivine phenocrysts, set in a crystalline groundmass of calcite, chromite, perovskite, phlogopite, apatite, ilmenite, titanite, sulphides, rutile and magnetite along with abundant alteration phases (i.e. serpentine, talc and secondary calcite). These features are typical of archetypal hypabyssal kimberlites. We examined primary fluid/melt inclusions in chromite, perovskite and apatite containing a diversity of daughter phases. Chromite and perovskite host polycrystalline inclusions containing abundant alkali-carbonates (i.e. enriched in K, Na, Ba, Sr), phosphates, Na-K chlorides, sulphides and equal to lesser quantities of olivine, phlogopite and pleonaste. In contrast, apatite hosts polycrystalline assemblages with abundant alkali-carbonates and Na-K chlorides and lesser amounts of olivine, monticellite and phlogopite. Numerous solid inclusions of shortite (Na2Ca2(CO3)3), Na-Sr-carbonates and apatite occur in groundmass calcite along with fluid inclusions containing daughter crystals of Na-carbonates and Na-chlorides. The primary inclusions in chromite, perovskite and apatite are considered to represent remnants of fluid(s)/melt(s) trapped during crystallisation of the host minerals, whereas the fluid inclusions in calcite are probably secondary in origin. The component proportions of these primary fluid/melt inclusions were estimated in an effort to constrain the composition of the evolving kimberlite melt. These estimates suggest melt evolution from a silicate-carbonate kimberlite melt that became increasingly enriched in carbonates, phosphates, alkalis and chlorides, in response to the fractional crystallisation of constituent minerals (i.e. olivine to apatite). The concentric alignment of crystals around the olivine kernel and ovoid shape of the magmaclast can be ascribed to the low viscosity of the kimberlite melt and rapid rotation whilst in a liquid or partial crystalline state, or to progressive layer-by-layer growth of the magmaclast. Although the mineralogy of our sample is similar to hypabyssal kimberlites worldwide, it differs from hypabyssal kimberlite units in the main Venetia pipes, which contain monticellite-phlogopite rich assemblages and segregationary matrix textures. Therefore magmaclast BI9883 probably originated from a batch of magma distinct from those that produced known hypabyssal units within the Venetia kimberlite cluster.-
DS201611-2110
2016
Giuliani, A.Giuliani, A., Soltys, A., Phillips, D., Kamenetsly, V.S., Maas, R., Geomann, K., Woodhead, J.D., Drysdale, R.N., Griffin, W.L.The final stages of kimberlite petrogenesis: petrography, mineral chemistry, melt inclusions and Sr-C-O isotope geochemistry of the Bultfontein kimberlite ( Kimberley, South Africa).Chemical Geology, in press available 15p.Africa, South AfricaDeposit - Bultfontein

Abstract: The petrogenesis of kimberlites commonly is obscured by interaction with hydrothermal fluids, including deuteric (late-magmatic) and/or groundwater components. To provide new constraints on the modification of kimberlite rocks during overprinting by such fluids and on the fractionation of kimberlite magmas during crystallisation, we have undertaken a detailed petrographic and geochemical study of a hypabyssal sample (BK) from the Bultfontein kimberlite (Kimberley, South Africa).
DS201707-1299
2017
Giuliani, A.Abersteiner, A., Giuliani, A., Kamenetsky, V.S., Phillips, D.Petrographic and melt inclusion constraints on the petrogenesis of a magmaclast from the Venetia kimberlite cluster, South Africa.Chemical Geology, Vol. 455, pp. 331-341.Africa, South Africadeposit - Venetia

Abstract: Kimberlitic magmaclasts are discrete ovoid magmatic fragments that formed prior to emplacement from disrupted kimberlite magma. To provide new constraints on the origin and evolution of the kimberlite melts, we document the mineralogy and petrography of a magmaclast recovered from one of the ca. 520 Ma Venetia kimberlites, South Africa. The sample (BI9883) has a sub-spherical shape and consists of a ~ 10 mm diameter central olivine macrocryst, surrounded by porphyritic kimberlite. The kimberlitic material consists of concentrically aligned, altered olivine phenocrysts, set in a crystalline groundmass of calcite, chromite, perovskite, phlogopite, apatite, ilmenite, titanite, sulphides, rutile and magnetite along with abundant alteration phases (i.e. serpentine, talc and secondary calcite). These features are typical of archetypal hypabyssal kimberlites. We examined primary fluid/melt inclusions in chromite, perovskite and apatite containing a diversity of daughter phases. Chromite and perovskite host polycrystalline inclusions containing abundant alkali-carbonates (i.e. enriched in K, Na, Ba, Sr), phosphates, Na-K chlorides, sulphides and equal to lesser quantities of olivine, phlogopite and pleonaste. In contrast, apatite hosts polycrystalline assemblages with abundant alkali-carbonates and Na-K chlorides and lesser amounts of olivine, monticellite and phlogopite. Numerous solid inclusions of shortite (Na2Ca2(CO3)3), Na-Sr-carbonates and apatite occur in groundmass calcite along with fluid inclusions containing daughter crystals of Na-carbonates and Na-chlorides. The primary inclusions in chromite, perovskite and apatite are considered to represent remnants of fluid(s)/melt(s) trapped during crystallisation of the host minerals, whereas the fluid inclusions in calcite are probably secondary in origin. The component proportions of these primary fluid/melt inclusions were estimated in an effort to constrain the composition of the evolving kimberlite melt. These estimates suggest melt evolution from a silicate-carbonate kimberlite melt that became increasingly enriched in carbonates, phosphates, alkalis and chlorides, in response to the fractional crystallisation of constituent minerals (i.e. olivine to apatite). The concentric alignment of crystals around the olivine kernel and ovoid shape of the magmaclast can be ascribed to the low viscosity of the kimberlite melt and rapid rotation whilst in a liquid or partial crystalline state, or to progressive layer-by-layer growth of the magmaclast. Although the mineralogy of our sample is similar to hypabyssal kimberlites worldwide, it differs from hypabyssal kimberlite units in the main Venetia pipes, which contain monticellite-phlogopite rich assemblages and segregationary matrix textures. Therefore magmaclast BI9883 probably originated from a batch of magma distinct from those that produced known hypabyssal units within the Venetia kimberlite cluster.
DS201707-1327
2017
Giuliani, A.Giuliani, A., Soltys, A., Phillips, D., Kamenetsky, V.S., Maas, R., Goemann, K., Woodhead, J.D., Drysdale, R.N., Griffin, W.L.The final stages of kimberlite petrogenesis: petrography, mineral chemistry, melt inclusions and Sr-C-O isotope geochemistry of the Bultfontein kimberlite ( Kimberley, South Africa.Chemical Geology, Vol. 455, pp. 342-256.Africa, South Africadeposit - Bultfontein

Abstract: The petrogenesis of kimberlites is commonly obscured by interaction with hydrothermal fluids, including deuteric (late-magmatic) and/or groundwater components. To provide new constraints on the modification of kimberlite rocks during fluid interaction and the fractionation of kimberlite magmas during crystallisation, we have undertaken a detailed petrographic and geochemical study of a hypabyssal sample (BK) from the Bultfontein kimberlite (Kimberley, South Africa). Sample BK consists of abundant macrocrysts (> 1 mm) and (micro-) phenocrysts of olivine and lesser phlogopite, smaller grains of apatite, serpentinised monticellite, spinel, perovskite, phlogopite and ilmenite in a matrix of calcite, serpentine and dolomite. As in kimberlites worldwide, BK olivine grains consist of cores with variable Mg/Fe ratios, overgrown by rims that host inclusions of groundmass phases (spinel, perovskite, phlogopite) and have constant Mg/Fe, but variable Ni, Mn and Ca concentrations. Primary multiphase inclusions in the outer rims of olivine and in Fe-Ti-rich (‘MUM’) spinel are dominated by dolomite, calcite and alkali carbonates with lesser silicate and oxide minerals. Secondary inclusions in olivine host an assemblage of Na-K carbonates and chlorides. The primary inclusions are interpreted as crystallised alkali-Si-bearing Ca-Mg-rich carbonate melts, whereas secondary inclusions host Na-K-rich C-O-H-Cl fluids. In situ Sr-isotope analyses of groundmass calcite and perovskite reveal similar 87Sr/86Sr ratios to perovskite in the Bultfontein and the other Kimberley kimberlites, i.e. magmatic values. The ?18O composition of the BK bulk carbonate fraction is above the mantle range, whereas the ?13C values are similar to those of mantle-derived magmas. The occurrence of different generations of serpentine and occasional groundmass calcite with high 87Sr/86Sr, and elevated bulk carbonate ?18O values indicate that the kimberlite was overprinted by hydrothermal fluids, which probably included a significant groundwater component. Before this alteration the groundmass included calcite, monticellite, apatite and minor dolomite, phlogopite, spinel, perovskite and ilmenite. Inclusions of groundmass minerals in olivine rims and phlogopite phenocrysts show that olivine and phlogopite also belong to the magmatic assemblage. We therefore suggest that the crystallised kimberlite was produced by an alkali-bearing, phosphorus-rich, silica-dolomitic melt. The alkali-Si-bearing Ca-Mg-rich carbonate compositions of primary melt inclusions in the outer rims of olivine and in spinel grains with evolved compositions (MUM spinel) support formation of these melts after fractionation of abundant olivine, and probably other phases (e.g., ilmenite and chromite). Finally, the similarity between secondary inclusions in kimberlite olivine of this and other worldwide kimberlites and secondary inclusions in minerals of carbonatitic, mafic and felsic magmatic rocks, suggests trapping of residual Na-K-rich C-O-H-Cl fluids after groundmass crystallisation. These residual fluids may have persisted in pore spaces within the largely crystalline BK groundmass and subsequently mixed with larger volumes of external fluids, which triggered serpentine formation and localised carbonate recrystallisation.
DS201708-1650
2017
Giuliani, A.Giuliani, A.Olivine zoning and the evolution of kimberlite systems.11th. International Kimberlite Conference, OralGlobalolivine
DS201708-1651
2017
Giuliani, A.Giuliani, A.Tracing mantle metasomatism using combined stable (S,O) and radiogenic (Sr, Nd, Hf, Pb) isotope geochemistry: case studies from mantle xenoliths of the Kimberley kimberlites.11th. International Kimberlite Conference, PosterAfrica, South Africadeposit - Kimberley Pool
DS201709-1989
2017
Giuliani, A.Giuliani, A., et al.Southwestern Africa on the burner: Pleistocene carbonatite volcanism linked to mantle upwelling in Angola. CatandaGoldschmidt Conference, abstract 1p.Africa, Angolacarbonatite, Catanda

Abstract: The origin of intraplate carbonatitic to alkaline volcanism in Africa is controversial. A tectonic control, i.e., decompression melting associated with far-field stress, is suggested by correlation with lithospheric sutures, repeated magmatic cycles in the same areas over several million years, synchronicity across the plate, and lack of clear age progression patterns. Conversely, a dominant role for mantle convection is supported by the coincidence of Cenozoic volcanism with regions of lithospheric uplift, positive free-air gravity anomalies, and slow seismic velocities. To improve constraints on the genesis of African volcanism, here we report the first radiometric and isotopic results for the Catanda complex, which hosts the only extrusive carbonatites in Angola. Apatite (U-Th-Sm)/He and phlogopite 40Ar/39Ar ages of Catanda aillikite lavas indicate eruption at ca. 500–800 ka, more than 100 m.y. after emplacement of abundant kimberlites and carbonatites in this region. The lavas share similar high-? (HIMU)–like Sr-Nd-Pb-Hf isotope compositions with other young mantle-derived volcanics from Africa (e.g., Northern Kenya Rift; Cameroon Line). The position of the Catanda complex in the Lucapa corridor, a long-lived extensional structure, suggests a possible tectonic control for the volcanism. The complex is also located on the Bié Dome, a broad region of fast Pleistocene uplift attributed to mantle upwelling. Seismic tomography models indicate convection of deep hot material beneath regions of active volcanism in Africa, including a large area encompassing Angola and northern Namibia. This is strong evidence that intraplate late Cenozoic volcanism, including the Catanda complex, resulted from the interplay between mantle convection and preexisting lithospheric heterogeneities.
DS201801-0017
2017
Giuliani, A.Giuliani, A., Campeny, M., Kamenetsky, V.S., Afonso, J.C., Maas, R., Melgarejo, J.C., Kohn, B.P., Matchen, E.L., Mangas, J., Goncalves, A.O., Manuel, J.Southwestern Africa on the burner: Pleistocene carbonatite volcanism linked to deep mantle upwelling in Angola.Geology, Vol. 45, 11, pp. 971=974.Africa, Angolacarbonatite - Catanda

Abstract: The origin of intraplate carbonatitic to alkaline volcanism in Africa is controversial. A tectonic control, i.e., decompression melting associated with far-field stress, is suggested by correlation with lithospheric sutures, repeated magmatic cycles in the same areas over several million years, synchronicity across the plate, and lack of clear age progression patterns. Conversely, a dominant role for mantle convection is supported by the coincidence of Cenozoic volcanism with regions of lithospheric uplift, positive free-air gravity anomalies, and slow seismic velocities. To improve constraints on the genesis of African volcanism, here we report the first radiometric and isotopic results for the Catanda complex, which hosts the only extrusive carbonatites in Angola. Apatite (U-Th-Sm)/He and phlogopite 40Ar/39Ar ages of Catanda aillikite lavas indicate eruption at ca. 500-800 ka, more than 100 m.y. after emplacement of abundant kimberlites and carbonatites in this region. The lavas share similar high-? (HIMU)-like Sr-Nd-Pb-Hf isotope compositions with other young mantle-derived volcanics from Africa (e.g., Northern Kenya Rift; Cameroon Line). The position of the Catanda complex in the Lucapa corridor, a long-lived extensional structure, suggests a possible tectonic control for the volcanism. The complex is also located on the Bié Dome, a broad region of fast Pleistocene uplift attributed to mantle upwelling. Seismic tomography models indicate convection of deep hot material beneath regions of active volcanism in Africa, including a large area encompassing Angola and northern Namibia. This is strong evidence that intraplate late Cenozoic volcanism, including the Catanda complex, resulted from the interplay between mantle convection and preexisting lithospheric heterogeneities.
DS201803-0450
2014
Giuliani, A.Giuliani, A., Phillips, D., Maas, R., Woodhead, J.D., Kendrick, M.A., Greig, A., Armstrong, R.A., Chew, D., Kamenetsky, V.S., Fiorentini, M.L.LIMA U-Pb ages link lithospheric mantle metasomatism to Karoo magmatism beneath the Kimberley region, South Africa.Earth and Planetary Science Letters, Vol. 401, pp. 132-147.Africa, South Africametasomatism

Abstract: The Karoo igneous rocks (174-185 Ma) of southern Africa represent one of the largest continental flood basalt provinces on Earth. Available evidence indicates that Karoo magmas either originated in the asthenosphere and were extensively modified by interaction with the lithospheric mantle prior to emplacement in the upper crust; or were produced by partial melting of enriched mantle lithosphere. However, no direct evidence of interaction by Karoo melts (or their precursors) with lithospheric mantle rocks has yet been identified in the suites of mantle xenoliths sampled by post-Karoo kimberlites in southern Africa. Here we report U-Pb ages for lindsleyite-mathiasite (LIMA) titanate minerals (crichtonite series) from three metasomatised, phlogopite and clinopyroxene-rich peridotite xenoliths from the ?84 Ma Bultfontein kimberlite (Kimberley, South Africa), located in the southern part of the Karoo magmatic province. The LIMA minerals appear to have formed during metasomatism of the lithospheric mantle by fluids enriched in HFSE (Ti, Zr, Hf, Nb), LILE (K, Ba, Ca, Sr) and LREE. LIMA U-Pb elemental and isotopic compositions were measured in situ by LA-ICP-MS methods, and potential matrix effects were evaluated by solution-mode analysis of mineral separates. LIMA minerals from the three samples yielded apparent U-Pb ages of , and (). A single zircon grain extracted from the ?190 Ma LIMA-bearing sample produced a similar U-Pb age of , within uncertainty of the LIMA ages. These data provide the first robust evidence of fluid enrichment in the lithospheric mantle beneath the Kimberley region at ?180-190 Ma, and suggest causation of mantle metasomatism by Karoo melts or their precursor(s). The results further indicate that U-Pb dating of LIMA minerals provides a new, accurate tool for dating metasomatic events in the lithospheric mantle.
DS201803-0451
2018
Giuliani, A.Giuliani, A., Woodhead, J.D., Phillips, D., Maas, R., Davies, G.R.Titanates of the lindsleyite mathiasite ( LIMA) group reveal isotope disequilibrium associated with metasomatism in the mantle beneath Kimberley ( South Africa).Earth and Planetary Science Letters, Vol. 482, pp. 253-264.Africa, South Africametasomatism

Abstract: Radiogenic isotope variations unrelated to radiogenic ingrowth are common between minerals found in metasomatised mantle xenoliths entrained in kimberlite, basalts and related magmas. As the metasomatic minerals are assumed to have been in isotopic equilibrium originally, such variations are typically attributed to contamination by the magma host and/or interaction with mantle fluids during or before xenolith transport to surface. However, the increasing evidence of metasomatism by multiple, compositionally distinct fluids permeating the lithospheric mantle, coeval with specific magmatic events, suggests that isotopic disequilibrium might be a consequence of discrete, though complex, metasomatic events. Here we provide clear evidence of elemental and Sr isotope heterogeneity between coeval Ti-rich LIMA (lindsleyite–mathiasite) minerals at the time of their formation in the mantle. LIMA minerals occur in close textural association with clinopyroxene and phlogopite in low-temperature (?800–900?°C), strongly metasomatised mantle xenoliths from the ?84 Ma Bultfontein kimberlite (South Africa). Previous U/Pb dating of the LIMA phases was used to argue that each xenolith recorded a single event of LIMA crystallisation at ?180–190 Ma, coeval with the emplacement of Karoo magmas. SEM imaging reveals that up to four types of LIMA phases coexist in each xenolith, and occasionally in a single LIMA grain. Major element and in situ Sr isotope analyses of the different LIMA types show that each phase has a distinct elemental composition and initial 87Sr/86Sr ratio (e.g., 0.7068–0.7086 and 0.7115–0.7129 for two LIMA types in a single xenolith; 0.7053-0.7131 across the entire sample suite). These combined age and isotopic constraints require that multiple fluids metasomatised these rocks at broadly the same time (i.e. within a few thousands to millions of years), and produced similar mineralogical features. Elemental and isotopic variations between different LIMA types could be due to interaction between one (or more) Karoo-related Ti-rich silicate melts and previously metasomatised, phlogopite-rich lithospheric mantle. This study demonstrates that mantle metasomatic assemblages seemingly generated in a single event may instead result from the infiltration of broadly coeval fluids with variable compositions. This in turn implies that the isotopic variations recorded in mantle rocks may be an inherent feature of metasomatism, and that hot fluids infiltrating a rock do not necessarily cause equilibration at the cm scale, as has been assumed previously. Simple modelling of solid-state diffusion in mantle minerals shows that isotopic disequilibrium may be preserved for up to hundreds of Myr at mantle lithosphere temperatures (?1100–1200?°C), unless subsequently affected by transient heating and/or fluid infiltration events. Radiogenic isotope disequilibrium associated with mantle metasomatism may therefore be a common feature of mantle xenoliths.
DS201803-0477
2018
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D.A new approach to reconstructing the composition and evolution of kimberlite melts: a case study of the archetypal Bultfontein kimberlite ( Kimberley, South Africa).Lithos, in press available Africa, South Africadeposit - Bultfontein

Abstract: The compositions of kimberlite melts at depth and upon emplacement in the upper crust remain elusive. This can be attributed to the unquantified effects of multiple processes, such as alteration, assimilation, xenocryst contamination, and fractional crystallisation. The inability to accurately constrain the composition and physical properties of kimberlite melts prevents a comprehensive understanding of their petrogenesis. To improve constraints on the compositions of kimberlite melts, we have combined modal analysis including the discrimination of xenocrystic from magmatic phases, with mineral chemistry determinations to reconstruct a whole-rock composition. We apply this approach to a sample of “fresh” macrocrystic hypabyssal kimberlite (sample BK-1) from the Bultfontein mine (Kimberley, South Africa). The accuracy of this whole-rock reconstruction method is validated by the similarity between reconstructed and measured whole-rock compositions. A series of corrections are then applied to account for the effects of post-emplacement serpentinisation, pre-emplacement olivine crystallisation, and the inclusion and assimilation of mantle material. This approach permits discernment of melt compositions at different stages of kimberlite evolution. The primitive melt parental to the Bultfontein kimberlite is estimated to contain 17.4-19.0?wt% SiO2, 20.2-22.8?wt% MgO, 20.9-21.9?wt% CaO, 2.1-2.3?wt% P2O5, 1.2-1.4?wt% TiO2, 0.9-1.1?wt% Al2O3, and 0.6-0.7?wt% K2O, and has a Mg# of 83.4-84.4. Primary volatile contents (i.e., after an attempt to account for volatile loss) are tentatively estimated at ~2.1-2.2?wt% H2O and ~22.9-25.4?wt% CO2. This composition is deficient in SiO2, MgO and H2O, but enriched in CaO and CO2 compared with most previous estimates of primitive kimberlite melts. We suggest that the primitive melt parental to the Bultfontein kimberlite was a transitional silicate-carbonate melt, which was progressively enriched in SiO2, MgO, Al2O3, Cr2O3, and Na2O through the assimilation of lithospheric mantle material. Comparisons with experimentally produced low-degree melts of carbonated lherzolite indicate that the Bultfontein kimberlite could have formed by ~0.5% melting of asthenospheric mantle at ~6.0-8.6?GPa (i.e., ~190-285?km) and ~1400-1500?°C. The low calculated Na2O contents (<0.2?wt%), which are inconsistent with derivation from low-degree melting of lherzolite, suggest that an alkali-bearing, volatile-rich fluid was exsolved during ascent or released after emplacement, and subsequently removed.
DS201806-1223
2018
Giuliani, A.Fitzpayne, A., Giuliani, A., Phillips, D., Wu, N.Kimberlite related metasomatism recorded in Marid and PIC mantle xenoliths. Kimberlites and orangeitesMineralogy and Petrology, in press available, 14p.Africa, South Africadeposit - Bultfontein

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) xenoliths are thought to be formed by intense Bprimary^ mantle metasomatism. These rocks also display secondary features, such as cross-cutting veins and geochemical zonation of matrix minerals, which probably reflect latermetasomatic events. To investigate the nature and origin(s) of these secondary features, 28 MARID and PIC xenoliths from southern African kimberlites and orangeites have been studied. MARID-hosted veins contain both carbonate and Ti-rich phases (e.g., titanite, phlogopite), suggesting that they formed by the infiltration of a carbonated silicate melt. Elevated TiO2 contents in MARID matrix mineral rims are spatially associated with carbonate-dominated veins, suggesting a genetic relationship between vein formation and geochemical zonation. Spongy rims around primaryMARID and PIC clinopyroxene are depleted in Na2O andAl2O3 relative to their cores, possibly reflecting mineral dissolution in the xenoliths during ascent and emplacement of the entraining kimberlite. The preservation of compositional differences between primary and secondary phases in MARID and PIC xenoliths indicates that metasomatism occurred shortly before, or broadly coeval with, kimberlite/orangeite magmatism; otherwise, at typical mantle temperatures, such features would have quickly re-equilibrated. Increased Na2O in some mineral rims (e.g., K-richterite) may therefore reflect equilibration with a more Na-enriched primitive kimberlite melt composition than is commonly suggested. Vein-hosted clinopyroxene 87Sr/86Sri (0.70539 ± 0.00079) in one MARID sample is intermediate between primary clinopyroxene in the sample (0.70814 ± 0.00002) and the host Bultfontein kimberlite (0.70432 ± 0.00005), suggesting that vein minerals are derived from interactions between primary MARID phases and kimberlite-related melts/fluids. Sulfur isotope compositions of barite (?34SVCDT = +4.69 ‰) and sulfides (?34SVCDT = ?0.69 ‰) in carbonate veins reflect equilibration at temperatures of 850-900 °C, consistent with sulfurrich melt/fluid infiltration in the lithospheric mantle. In contrast, vein carbonate C-O isotope systematics (?13CVPDB = ?9.18 ‰ ?18OVSMOW = +17.22‰) are not typical of kimberlites or other mantle carbonates (?13CVPDB = ?3 to ?8‰ ?18OVSMOW = 6 to 9 ), and may represent post-emplacement hydrothermal interactions of the cooling kimberlite with crustal fluids. These constraints suggest protracted metasomatism of MARID rocks shortly before and during entrainment by the host kimberlite.
DS201807-1527
2018
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D.Crystallisation sequence and magma evolution of the De Beers dyke ( Kimberley, South Africa).Mineralogy and Petrology, June 14, DOI:10.1007/ s00710-018 -0588-5, 16p.Africa, South Africadeposit - De Beers dyke

Abstract: We present petrographic and mineral chemical data for a suite of samples derived from the De Beers dyke, a contemporaneous, composite intrusion bordering the De Beers pipe (Kimberley, South Africa). Petrographic features and mineral compositions indicate the following stages in the evolution of this dyke: (1) production of antecrystic material by kimberlite-related metasomatism in the mantle (i.e., high Cr-Ti phlogopite); (2) entrainment of wall-rock material during ascent through the lithospheric mantle, including antecrysts; (3) early magmatic crystallisation of olivine (internal zones and subsequently rims), Cr-rich spinel, rutile, and magnesian ilmenite, probably on ascent to the surface; and (4) crystallisation of groundmass phases (i.e., olivine rinds, Fe-Ti-rich spinels, perovskite, apatite, monticellite, calcite micro-phenocrysts, kinoshitalite-phlogopite, barite, and baddeleyite) and the mesostasis (calcite, dolomite, and serpentine) on emplacement in the upper crust. Groundmass and mesostasis crystallisation likely forms a continuous sequence with deuteric/hydrothermal modification. The petrographic features, mineralogy, and mineral compositions of different units within the De Beers dyke are indistinguishable from one another, indicating a common petrogenesis. The compositions of antecrysts (i.e., high Cr-Ti phlogopite) and magmatic phases (e.g., olivine rims, magnesian ilmenite, and spinel) overlap those from the root zone intrusions of the main Kimberley pipes (i.e., Wesselton, De Beers, Bultfontein). However, the composition of these magmatic phases is distinct from those in ‘evolved’ intrusions of the Kimberley cluster (e.g., Benfontein, Wesselton water tunnel sills). Although the effects of syn-emplacement flow processes are evident (e.g., alignment of phases parallel to contacts), there is no evidence that the De Beers dyke has undergone significant pre-emplacement crystal fractionation (e.g., olivine, spinel, ilmenite). This study demonstrates the requirement for detailed petrographic and mineral chemical studies to assess whether individual intrusions are in fact ‘evolved’; and that dykes are not necessarily produced by differentiated magmas.
DS201808-1764
2018
Giuliani, A.Lim, E., Giuliani, A., Phillips, D., Goemann, K.Origin of complex zoning in olivine from diverse, Diamondiferous kimberlites and tectonic settings: Ekati ( Canada), Alto Paranaiba ( Brazil) and Kaalvallei ( South Africa).Mineralogy and Petrology, doi.org/10.1007/s00710-018-0607-6 16p.Canada, Northwest Territories, South America, Brazildeposit - Ekati, Grizzly, Kaola, Limpeza-18, Tres Ranchos-04, Kaalvallei, Samada, New Robinson

Abstract: Olivine in kimberlites can provide unique insights into magma petrogenesis, because it is the most abundant xenocrystic phase and a stable magmatic product over most of the liquid line of descent. In this study we examined the petrography and chemistry of olivine in kimberlites from different tectonic settings, including the Slave craton, Canada (Ekati: Grizzly, Koala), the Brasilia mobile belt (Limpeza-18, Tres Ranchos-04), and the Kaapvaal craton, South Africa (Kaalvallei: Samada, New Robinson). Olivine cores display a wide range of compositions (e.g., Mg#?=?78-95). The similarity in olivine composition, resorption of core zones and inclusions of mantle-derived phases, indicates that most olivine cores originated from the disaggregation of mantle peridotites, including kimberlite-metasomatised lithologies (i.e. sheared lherzolites and megacrysts). Olivine rims typically show a restricted range of Mg#, with decreasing Ni and increasing Mn and Ca contents, a characteristic of kimberlitic olivine worldwide. The rims host inclusions of groundmass minerals, which implies crystallisation just before and/or during emplacement. There is a direct correlation between olivine rim composition and groundmass mineralogy, whereby high Mg/Fe rims are associated with carbonate-rich kimberlites, and lower Mg/Fe rims are correlated with increased phlogopite and Fe-bearing oxide mineral abundances. There are no differences in olivine composition between explosive (Grizzly) and hypabyssal (Koala) kimberlites. Olivine in kimberlites also displays transitional zones and less common internal zones, between cores and rims. The diffuse transitional zones exhibit intermediate compositions between cores and rims, attributed to partial re-equilibration of xenocrystic cores with the ascending kimberlite melt. In contrast, internal zones form discrete layers with resorbed margins and restricted Mg# values, but variable Ni, Mn and Ca concentrations, which indicates a discrete crystallization event from precursor kimberlite melts at mantle depths. Overall, olivine exhibits broadly analogous zoning in kimberlites worldwide. Variable compositions for individual zones relate to different parental melt compositions rather than variations in tectonic setting or emplacement mechanism.
DS201809-2006
2018
Giuliani, A.Castillo-Oliver, M., Giuliani, A., Griffin, W.L., O'Reilly, S.Y.Characterisation of primary and secondary carbonates in hypabyssal kimberlites: an integrated compositional and Sr-isotopic approach. Mineralogy and Petrology, doi.org/10.1007/s00710-018-0626-3 13p.Africa, South Africa, Australia, Europe, Finland, Canada, Northwest Territoriesdeposit - Wesselton, De Beers, Bultfontein, Benfontein, Jagersfontein, Cullinan, Melita, Pipe 1, Grizzley, Koala

Abstract: Carbonates in fresh hypabyssal kimberlites worldwide have been studied to understand their origin [i.e. primary magmatic (high T) versus deuteric (‘low T’) versus hydrothermal/alteration (‘low T’)] and identify optimal strategies for petrogenetic studies of kimberlitic carbonates. The approach presented here integrates detailed textural characterisation, cathodoluminescence (CL) imaging, in situ major- and trace-element analysis, as well as in situ Sr-isotope analysis. The results reveal a wide textural diversity. Calcite occurs as fine-grained groundmass, larger laths, segregations, veins or as a late crystallising phase, replacing olivine or early carbonates. Different generations of carbonates commonly coexist in the same kimberlite, each one defined by a characteristic texture, CL response and composition (e.g., variable Sr and Ba concentrations). In situ Sr isotope analysis revealed a magmatic signature for most of the carbonates, based on comparable 87Sr/86Sr values between these carbonates and the coexisting perovskite, a robust magmatic phase. However, this study also shows that in situ Sr isotope analysis not always allow distinction between primary (i.e., magmatic) and texturally secondary carbonates within the same sample. Carbonates with a clear secondary origin (e.g., late-stage veins) occasionally show the same moderately depleted 87Sr/86Sr ratios of primary carbonates and coexisting perovskite (e.g., calcite laths-shaped crystals with 87Sr/86Sr values identical within uncertainty to those of vein calcite in the De Beers kimberlite). This complexity emphasises the necessity of integrating detailed petrography, geochemical and in situ Sr isotopic analyses for an accurate interpretation of carbonate petrogenesis in kimberlites. Therefore, the complex petrogenesis of carbonates demonstrated here not only highlights the compositional variability of kimberlites, but also raises concerns about the use of bulk-carbonate C-O isotope studies to characterise the parental melt compositions. Conversely, our integrated textural and in situ study successfully identifies the most appropriate (i.e. primary) carbonates for providing constraints on the isotopic parameters of parental kimberlite magmas.
DS201810-2315
2018
Giuliani, A.Fitzpayne, A., Giuliani, A., Hergt, J., Phillips, D., Janney, P.New geochemical constraints on the origins of MARID and PIC rocks: implications for mantle metasomatism and mantle -derived potassic magmatism.Lithos, Vol. 318-319, pp. 478-493.Mantlemetasomatism
DS201812-2771
2018
Giuliani, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Giuliani, A., Howarth, G.H., Castillo-Oliver, M., Thomspon, J., Kamenetsky,M., Cherry, A.Composition and emplacement of the Benfontein kimberlite sill complex ( Kimberley, South Africa): textural, petrographic and melt inclusion constraints.Lithos, doi.org/10.1016 /jlithos.2018 .11.017 32p.Africa, South Africadeposit - Benfontein

Abstract: The Benfontein kimberlite is a renowned example of a sill complex and provides an excellent opportunity to examine the emplacement and evolution of intrusive kimberlite magmas. We have undertaken a detailed petrographic and melt inclusion study of the Benfontein Upper, Middle and Lower sills. These sills range in thickness from 0.25 to 5?m. New perovskite and baddeleyite U/Pb dating produced ages of 85.7?±?4.4?Ma and 86.5?±?2.6?Ma, respectively, which are consistent with previous age determinations and indicate emplacement coeval with other kimberlites of the Kimberley cluster. The Benfontein sills are characterised by large variations in texture (e.g., layering) and mineral modal abundance between different sill levels and within individual samples. The Lower Sill is characterised by carbonate-rich diapirs, which intrude into oxide-rich layers from underlying carbonate-rich levels. The general paucity of xenogenic mantle material in the Benfontein sills is attributed to its separation from the host magma during flow differentiation during lateral spreading. The low viscosity is likely responsible for non-explosive emplacement of the Benfontein sills, while the rhythmic layering is attributed to multiple magma injections. The Benfontein sills are marked by the excellent preservation of olivine and groundmass mineralogy, which is composed of monticellite, spinel, perovskite, baddeleyite, ilmenite, apatite, calcite, dolomite along with secondary serpentine and glagolevite [NaMg6[Si3AlO10](OH,O)8•H2O]. This is the first time glagolevite is reported in kimberlites. Groundmass spinel exhibits atoll-textures and is composed of a magnesian ulvöspinel magnetite (MUM) or chromite core, surrounded by occasional pleonaste and a rim of Mg-Al-magnetite. We suggest that pleonaste crystallised as a magmatic phase, but was resorbed back into the residual host melt and/or removed by alteration. Analyses of secondary inclusions in olivine and primary inclusions in monticellite, spinel, perovskite, apatite and interstitial calcite are largely composed of Ca-Mg carbonates and, to a lesser extent, alkali-carbonates and other phases. These inclusions probably represent the entrapment of variably differentiated parental kimberlite melts, which became progressively more enriched in carbonate, alkalis, halogens and sulphur during crystal fractionation. Carbonate-rich diapirs from the Lower Sill contain more exotic phase assemblages (e.g., Ba-Fe titanate, barite, ancylite, pyrochlore), which probably result from the extreme differentiation of residual kimberlite melts followed by physical separation and isolation from the parental carbonate-rich magma. It is likely that any alkali or halogen rich minerals crystallising in the groundmass were removed from the groundmass during syn?/post-magmatic alteration, or in the case of Na, remobilised to form secondary glagolevite. The Benfontein sill complex therefore provides a unique example of how the composition of kimberlites may be modified after magma emplacement in the upper crust.
DS201812-2809
2018
Giuliani, A.Fitzpayne, A., Giuliani, A., Hergt, J., Phillips, D., Janney, P.New geochemical constraints on the origins of MARID and PIC rocks: implications for mantle metasomatism and mantle derived potassic magmatism. ( kimberlite)Lithos, Vol. 318-319, pp. 478-493.Globallamproites

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks are unusual mantle samples entrained by kimberlites and other alkaline volcanic rocks. The formation of MARID rocks remains hotly debated. Although the incompatible element (for example, large ion lithophile element) enrichment in these rocks suggests that they formed by mantle metasomatism, the layered textures of some MARID samples (and MARID veins in composite xenoliths) are more indicative of formation by magmatic processes. MARID lithologies have also been implicated as an important source component in the genesis of intraplate ultramafic potassic magmas (e.g., lamproites, orangeites, ultramafic lamprophyres), due to similarities in their geochemical and isotopic signatures. To determine the origins of MARID and PIC xenoliths and to understand how they relate to alkaline magmatism, this study presents new mineral major and trace element data and bulk-rock reconstructions for 26 MARID and PIC samples from the Kimberley-Barkly West area in South Africa. Similarities between compositions of PIC minerals and corresponding phases in metasomatised mantle peridotites are indicative of PIC formation by pervasive metasomatic alteration of peridotites. MARID genesis remains a complicated issue, with no definitive evidence precluding either the magmatic or metasomatic model. MARID minerals exhibit broad ranges in Mg# (e.g., clinopyroxene Mg# from 82 to 91), which may be indicative of fractionation processes occurring in the MARID-forming fluid/melt. Finally, two quantitative modelling approaches were used to determine the compositions of theoretical melts in equilibrium with MARID rocks. Both models indicate that MARID-derived melts have trace element patterns resembling mantle-derived potassic magma compositions (e.g., lamproites, orangeites, ultramafic lamprophyres), supporting inferences that these magmas may originate from MARID-rich mantle sources.
DS201902-0254
2019
Giuliani, A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Giuliani, A., Howarth, G.H., Castillo-Oliver, M., Thompson, J., Kamenetsky, M., Cherry, A.Composition and emplacement of the Benfontein kimberlite sill complex ( Kimberley, South Africa): textural, petrographic and melt inclusion constraints.Lithos, Vol. 324-325, pp. 297-314.Africa, South Africadeposit - Benfontein

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

Abstract: Djerfisherite (K6(Fe,Ni,Cu)25S26Cl) occurs as an accessory phase in the groundmass of many kimberlites, kimberlite-hosted mantle xenoliths, and as a daughter inclusion phase in diamonds and kimberlitic minerals. Djerfisherite typically occurs as replacement of pre-existing Fe-Ni-Cu sulphides (i.e. pyrrhotite, pentlandite and chalcopyrite), but can also occur as individual grains, or as poikilitic phase in the groundmass of kimberlites. In this study, we present new constraints on the origin and genesis of djerfisherite in kimberlites and their entrained xenoliths. Djerfisherite has extremely heterogeneous compositions in terms of Fe, Ni and Cu ratios. However, there appears to be no distinct compositional range of djerfisherite indicative of a particular setting (i.e. kimberlites, xenoliths or diamonds), rather this compositional diversity reflects the composition of the host kimberlite melt and/or interacting metasomatic medium. In addition, djerfisherite may contain K and Cl contents less than the ideal formula unit. Raman spectroscopy and electron backscatter diffraction (EBSD) revealed that these K-Cl poor sulphides still maintain the same djerfisherite crystal structure. Two potential mechanisms for djerfisherite formation are considered: (1) replacement of pre-existing Fe-Ni-Cu sulphides by djerfisherite, which is attributed to precursor sulphides reacting with metasomatic K-Cl bearing melts/fluids in the mantle or the transporting kimberlite melt; (2) direct crystallisation of djerfisherite from the kimberlite melt in groundmass or due to kimberlite melt infiltration into xenoliths. The occurrence of djerfisherite in kimberlites and its mantle cargo from localities worldwide provides strong evidence that the metasomatising/infiltrating kimberlite melt/fluid was enriched in K and Cl. We suggest that kimberlites originated from melts that were more enriched in alkalis and halogens relative to their whole-rock compositions.
DS201902-0271
2019
Giuliani, A.Fitzpayne, A., Giuliani, A., Maas, R., Hergt, J., Janney, P., Phillips, D.Progressive metasomatism of the mantle by kimberlite melts: Sr-Nd-Hf-Pb isotope compositions of MARID and PIC minerals.Earth and Planetary Science Letters, Vol. 506, pp. 15-26.Africa, South Africadeposit - Newlands, Kimberley, Bultfontein

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks occur as mantle-derived xenoliths in kimberlites and other alkaline volcanic rocks. Both rock types are alkaline and ultramafic in composition. The H2O and alkali metal enrichments in MARID and PIC rocks, reflected in abundant phlogopite, have been suggested to be caused by extreme mantle metasomatism. Radiogenic (Sr-Nd-Hf-Pb) isotope and trace element compositions for mineral separates from MARID (clinopyroxene and amphibole) and PIC (clinopyroxene only) samples derived from Cretaceous kimberlites (Kimberley) and orangeites (Newlands) from South Africa are used here to examine the source(s) of mantle metasomatism. PIC clinopyroxene is relatively homogeneous, with narrow ranges in initial isotopic composition (calculated to the emplacement age of the host Bultfontein kimberlite; 87Sr/86Sri: 0.7037-0.7041; ?Ndi: +3.0 to +3.6; ?Hfi: +2.2 to +2.5; 206Pb/204Pbi: 19.72-19.94) similar to kimberlite values. This is consistent with PIC rocks representing peridotites modified by intense metasomatic interaction with kimberlite melts. The MARID clinopyroxene and amphibole separates () studied here display broader ranges in isotope composition (e.g., 87Sr/86Sri: 0.705-0.711; ?Ndi: ?11.0 to ?1.0; ?Hfi: ?17.9 to ?8.5; 206Pb/204Pbi: 17.33-18.72) than observed in previous studies of MARID rocks. The Nd-Hf isotope compositions of kimberlite-derived MARID samples fall below the mantle array (??Hfi between ?13.0 and ?2.4), a feature reported widely for kimberlites and other alkaline magmas. We propose that such displacements in MARID minerals result from metasomatic alteration of an initial “enriched mantle” MARID composition (i.e., 87Sr/86Sri = 0.711; ?Ndi = ?11.0; ?Hfi = ?17.9; and 206Pb/204Pbi = 17.3) by the entraining kimberlite magma (87Sr/86Sr; ?Nd; ?Hf; 206Pb/204Pb). A model simulating the flow of kimberlite magma through a mantle column, thereby gradually equilibrating the isotopic and chemical compositions of the MARID wall-rock with those of the kimberlite magma, broadly reproduces the Sr-Nd-Hf-Pb isotope compositions of the MARID minerals analysed here. This model also suggests that assimilation of MARID components could be responsible for negative ??Hfi values in kimberlites. The isotopic composition of the inferred initial MARID end-member, with high 87Sr/86Sr and low ?Nd, ?Hf, and 206Pb/204Pb, resembles those found in orangeites, supporting previous inferences of a genetic link between MARID-veined mantle and orangeites. The metasomatic agent that produced such compositions in MARID rocks must be more extreme than the EM-II mantle component and may relate to recycled material that experienced long-term storage in the lithospheric mantle.
DS201904-0736
2019
Giuliani, A.Fitzpayne, A., Giuliani, A., Harris, C., Thomassot, E., Cheng, C., Hergt, J.Evidence for subduction related signatures in the southern African lithosphere from the N-O isotopic composition of metasomatic mantle minerals.Geochimica et Cosmochimica Acta, in press available 21p.Africa, South Africadeposit - Bultfontein

Abstract: Current understanding of the fate of subducted material (and related fluids) in the deep Earth can be improved by combining major and trace element geochemistry with stable isotopic compositions of mantle rocks or minerals. Limited isotopic fractionation during high temperature processes means that significant deviations from mantle-like isotope ratios in mantle rocks probably result from recycling of surficial material. To determine the effects and origins of mantle metasomatic fluids/melts, new ?15N and ?18O data have been collected for thirteen mantle xenoliths - harzburgites, wehrlites, lherzolites, and MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) rocks - from the Bultfontein kimberlite (Kimberley, South Africa), which show varying degrees of metasomatism. The ?18O values of olivine and orthopyroxene in phlogopite-free harzburgites match the mantle composition (?18Oolivine?=?+5.2?±?0.3‰; ?18Oorthopyroxene?=?+5.7?±?0.3‰; 2?s.d.), consistent with previous inferences that harzburgites were formed by interaction with ancient silica-rich melts unrelated to subduction processes. Wehrlite samples display mineral compositional characteristics (e.g., low La/Zr in clinopyroxene) resembling those of other products of kimberlite melt metasomatism, such as PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks. The inferred interaction with kimberlite melts may be responsible for O isotopic disequilibrium between clinopyroxene and olivine (?18O?=?+0.2‰) in the wehrlites of this study. In contrast with broadly mantle-like ?18O values, the ?15N value of phlogopite in a wehrlite sample (+5.9‰) differs from the mantle composition (?15N?=??5?±?2‰). This unusual N isotopic composition in kimberlite-related mantle products might indicate that a recycled crustal component occurred in the source of the Kimberley kimberlites, or was assimilated during interaction with the lithospheric mantle. Similar major and trace element characteristics in clinopyroxene from phlogopite-lherzolite and MARID samples suggest metasomatism by fluids of similar composition. Lherzolite and MARID clinopyroxene ?18O values (as low as +4.4‰) extend below those reported in mantle peridotites (i.e. ?18Oclinopyroxene?=?+5.6?±?0.3‰; 2?s.d.), and strong negative correlations are found between mineral ?18O values and major element compositions (e.g., Na2O contents in clinopyroxene). Furthermore, phlogopite ?15N values (+4 to +7‰) in the studied lherzolite and MARID samples are higher than mantle values. Combined, the low ?18O-high ?15N isotopic signatures of MARID and lherzolite samples suggest progressive mantle metasomatism by a melt containing a recycled oceanic crust (eclogitic) component. This study demonstrates that progressive enrichment of the subcontinental lithospheric mantle may be inextricably linked to plate tectonics via recycling of subducted crustal material into the deep mantle.
DS201905-1033
2019
Giuliani, A.Giuliani, A., Martin, L.A.J., Soltys,A., Griffin, W.L.Mantle like oxygen isotopes in kimberlites determined by in situ SIMS analyses of zoned olivine.Geochimica et Cosmochimica Acta, in press available, 19p.Africa, South Africa, Canada, South America, Brazildeposit - Lac de Gras, Paranaiba

Abstract: Kimberlites are the deepest melts produced on Earth that are erupted at the surface and can therefore provide unique insights into the composition and evolution of the mantle. Radiogenic isotopes provide ambiguous evidence for the occurrence of recycled crustal material in kimberlite sources. Oxygen isotopes can fractionate significantly only in the shallow crust, and thus represent a powerful tracer of subducted material in the sources of kimberlite. To constrain the oxygen isotope composition of kimberlite melts, we have examined olivine grains in eleven Cretaceous to Eocene archetypal kimberlites from southern Africa, Lac de Gras (Canada) and Alto Paranaiba (Brazil), which exhibit radiogenic isotope evidence for recycled crustal material in their sources including highly radiogenic Pb isotopes and Nd-Hf isotope compositions deviating below the mantle array. Olivine grains are commonly zoned between a mantle-derived xenocrystic core and one or more magmatic overgrowths, i.e. occasional internal zones, ubiquitous rims and rare rinds (moving outward from the core). The oxygen isotope composition of different olivine zones was determined in situ within separated olivine grains by secondary ion mass spectrometry (SIMS) after point selection using back-scattered electron (BSE) images combined with major and minor element analyses. With the exception of a few cores, the ?18O values of different olivine zones do not deviate from typical mantle olivine values of 5.18?±?0.28‰ (Mattey et al., 1994). There are no correlations between oxygen isotopes and major/minor element compositions for internal zones and rims from individual localities or in the entire dataset. This indicates that the oxygen isotope composition of kimberlite melts is not affected by melt differentiation to the point of olivine rim crystallisation. However, olivine rinds from the Koala kimberlite (Canada) display an inverse correlation between ?18O and Mn-Ca concentrations, with ?18O values extending below the mantle range, which is probably due to carbonate fractionation, CO2 degassing and/or assimilation of serpentine-rich material after kimberlite emplacement in the upper crust. The mantle-like ?18O composition of olivine internal zones and rims suggests that assimilation of mantle material and liberation of a CO2-rich phase during ascent in the mantle do not significantly modify the original ?18O signature of kimberlite melts. Modelling of oxygen isotope fractionation shows that up to 15 wt% of CO2 can be lost by kimberlites en route to the upper crust. Our results combined with mass balance calculations indicate that only a limited amount (<5-10 wt%) of recycled crustal material could occur in the source of kimberlites from southern Africa, Lac de Gras and Alto Paranaiba, or that the recycled material had an oxygen isotope composition similar to the mantle.
DS201905-1078
2019
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D.Crystallization sequence and magma evolution of the De Beers dyke ( Kimberley, South Africa).Mineralogy and Petrology, doi.org/10.1007/ s00710-018-0588-5 17p.Africa, South Africadeposit - De Beers dyke

Abstract: We present petrographic and mineral chemical data for a suite of samples derived from the De Beers dyke, a contemporaneous, composite intrusion bordering the De Beers pipe (Kimberley, South Africa). Petrographic features and mineral compositions indicate the following stages in the evolution of this dyke: (1) production of antecrystic material by kimberlite-related metasomatism in the mantle (i.e., high Cr-Ti phlogopite); (2) entrainment of wall-rock material during ascent through the lithospheric mantle, including antecrysts; (3) early magmatic crystallisation of olivine (internal zones and subsequently rims), Cr-rich spinel, rutile, and magnesian ilmenite, probably on ascent to the surface; and (4) crystallisation of groundmass phases (i.e., olivine rinds, Fe-Ti-rich spinels, perovskite, apatite, monticellite, calcite micro-phenocrysts, kinoshitalite-phlogopite, barite, and baddeleyite) and the mesostasis (calcite, dolomite, and serpentine) on emplacement in the upper crust. Groundmass and mesostasis crystallisation likely forms a continuous sequence with deuteric/hydrothermal modification. The petrographic features, mineralogy, and mineral compositions of different units within the De Beers dyke are indistinguishable from one another, indicating a common petrogenesis. The compositions of antecrysts (i.e., high Cr-Ti phlogopite) and magmatic phases (e.g., olivine rims, magnesian ilmenite, and spinel) overlap those from the root zone intrusions of the main Kimberley pipes (i.e., Wesselton, De Beers, Bultfontein). However, the composition of these magmatic phases is distinct from those in ‘evolved’ intrusions of the Kimberley cluster (e.g., Benfontein, Wesselton water tunnel sills). Although the effects of syn-emplacement flow processes are evident (e.g., alignment of phases parallel to contacts), there is no evidence that the De Beers dyke has undergone significant pre-emplacement crystal fractionation (e.g., olivine, spinel, ilmenite). This study demonstrates the requirement for detailed petrographic and mineral chemical studies to assess whether individual intrusions are in fact ‘evolved’; and that dykes are not necessarily produced by differentiated magmas.
DS201908-1773
2019
Giuliani, A.Bussweiler, Y., Giuliani, A., Greig, A., Kjarsgaard, B.A., Petts, D., Jackson, S.E., Barrett, N., Luo, Y., Pearson, D.G.Trace element analysis of high-Mg olivine by LA-ICP-MS - characterization of natural olivine standards for matrix-matched calibration and application to mantle peridotites.Chemical Geology, Vol. 524, pp. 136-157.Mantleperidotite

Abstract: The trace element composition of olivine is becoming increasingly important in petrological studies due to the ubiquity of olivine in the Earth's upper mantle and in primitive magmatic rocks. The LA-ICP-MS method allows for the routine analysis of trace elements in olivine to sub-ppm levels, but a major drawback of this method is the lack of knowledge about possible downhole fractionation effects when non matrix-matched calibration is used. In this contribution, we show that matrix-matched (i.e., olivine-based) calibration is preferable for small laser spot sizes (<100??m) due to significant laser-induced inter-element fractionation between olivine and commonly used silicate glass calibration materials, e.g., NIST SRM 612, GSD-1G and BHVO-2G. As a result, we present two Mg-rich natural olivine standards (355OL and SC-GB) that have been characterized by independent methods (EPMA, solution ICP-MS), and by LA-ICP-MS in four different laboratories. These natural olivines have been used 1) as primary standards for the matrix-matched calibration of olivine samples for most elements of interest (e.g., Li, Na, Al, P, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn), and 2) as secondary standards to assess the accuracy of results. Comparison of olivine- and silicate glass-calibrated results for natural peridotitic olivine reveals that matrix-matched calibration is essential when using small laser spot sizes (<100??m) in order to mitigate downhole fractionation effects for certain elements, especially Na, P, Mn, Co, Ni and Zn. If matrix-matched calibration is not feasible, we recommend that spot sizes of ?100??m, laser fluence of ?4.0?J/cm2, and total laser shot counts of ?250 (e.g., 5?Hz repetition rate for 50?s) are used in order to minimize fractionation effects between olivine and silicate glass calibration materials. We demonstrate the applicability of matrix-matched calibration on olivine from a suite of different mantle peridotite xenoliths sampled by kimberlites and alkali basalts from on-craton and off-craton localities.
DS201909-2090
2019
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D.Apatite geochemistry provides insights into the late magmatic evolution of kimberlites.Goldschmidt2019, 1p. AbstractAfrica, South Africadeposit - Kimberley

Abstract: The late evolution of kimberlite magmas, i.e., during and-following emplacement into the upper crust, remains a-controversial aspect of kimberlite petrogenesis. Likewise, it is-unclear whether or not there is a link between melt composition-and the emplacement mechanism of intrusive kimberlites (i.e.,-planar dykes/sills vs. irregular intrusions in the root zone of-pipes). Resolving these issues is hampered by the absence of-comparative studies of late-magmatic kimberlite phases (e.g.,-apatite, monticellite, mica) in dykes, sills, and root-zone-intrusions from the same locality.-Here we report petrographic and mineral-chemical results-for groundmass phases in samples of dykes, sills, and root zone-intrusions from the Kimberley kimberlites (South Africa).-Early crystalised phases (e.g., olivine, spinel) in dykes/sills and-root-zone intrusions have indistingushable compositions, and-hence crystallised from similar primitive melts. Conversely,-apatite major element compositions are variable and can-discriminate dykes/sills (i.e., low and constant Sr, with-increasing Si) from root zone intrusions (high but variable Sr,-low and constant Si). The Sr depletion in root zone apatite is-interpreted to represent fractional crystallisation of earlier-apatite, perovskite, and calcite from a broadly similar parental-melt. Silica enrichment of apatite from dykes/sills may be-attributed to the coupled incorporation of CO32- and Si into the-apatite structure, reflecting higher CO2 contents in the melts-that formed dykes/sills. CO2 enrichment in the dykes/sills is-consistent with petrographic obervations. Dykes/sills are-enriched in carbonates, may contain dolomite, and are depleted-in mica and monticellite compared to the groundmass of rootzone-kimberlites. This suggests the melts parental to-dykes/sills have a higher CO2/H2O ratio compared to those-parental to root zone intrusions. These two distinct melt-evolution paths cannot be due to crustal contamination before-emplacement because the Sr-isotope compositions of latecrystallised-carbonates are indistinguishable in dykes/sills and-root-zone intrusions. We speculate that CO2 is better retained-in dykes/sills due to a higher confining pressure (i.e., lack of-breakthrough to the surface).-
DS201910-2253
2019
Giuliani, A.Dalton, H., Giuliani, A., Phillips, D., Hergt, J., O'Brien, H.Petrographic and geochemical variations in the Kaavi-Kuopio kimberlite field, Finland: the role of mantle assimilation.Goldschmidt2019, 1p. AbstractEurope, Finlanddeposit - Kaavi-Kuopio

Abstract: Kimberlites are silica-poor, volatile-rich (CO2 ± H2O), volcanic rocks that are often described as ‘hybrid’, because their parental magmas include abundant xenocrystic (crustand mantle-derived) components. Unravelling the influence of mantle assimilation on kimberlite melt compositions represents an outstanding question of kimberlite petrology. To address this issue, we have carried out a comprehensive geochemical and petrographic investigation of nine kimberlites from the Kaavi-Kuopio field in Finland, that were emplaced on the southern margin of the Karelian Craton in the Neoproterozoic (~550-600 Ma). Olivine is the dominant mineral phase in kimberlites (~50 vol.%) with cores mainly derived from the disaggregation of mantle peridotite. In contrast, olivine rims crystallise directly from the kimberlitic melt and their Mg# (Mg/(Mg+Fe)) typically show remarkable homogeneity within and between kimberlites of a single cluster and field (e.g., Lac de Gras). The Kaavi-Kuopio kimberlites appear to represent a unique case where there is a (statistically) significant difference between the average Mg# of olivine rims in different pipes (89.9 ± 0.2 to 88.5 ± 0.3). Importantly, the Mg# of olivine rims exhibit a strong correlation with the Mg# of olivine cores. Furthermore, the compositions of olivine cores (and rims) exhibit a strong correlation with those of spinel (e.g., Mg#, TiO2 contents). These geochemical variations correlate with the modal mineralogy of the kimberlites: for example, higher abundances of monticellite and lower abundances of ilmenite are associated with higher Mg# olivine. The robust relationship between entrained and assimilated lithospheric mantle material (i.e. olivine cores) and magmatic components (i.e. olivine rims, spinel, and other groundmass minerals) suggests that assimilation of lithospheric mantle has impacted the compositions of kimberlitic melts to a greater extent than previously recognised. These new data also suggest significant variations in the composition of the mantle lithosphere beneath the Kaavi-Kuopio kimberlites, which are spaced less than 10 km apart.
DS201910-2257
2019
Giuliani, A.Fitzpayne, A., Giuliani, A., Maas, R., Hergt, J., Janney, P., Phillips, D.Progressive metasomatism of the mantle by kimberliitic melts: Sr-Nd-Hf-Pb isotopic composition of MARID and PIC minerals.Goldschmidt2019, 1p. AbstractMantlemetasomatism

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks occur as mantle-derived xenoliths in kimberlites and other alkaline volcanic rocks. Both rock types are alkaline and ultramafic in composition. The H2O and alkali metal enrichments in MARID and PIC rocks, reflected in abundant phlogopite, have been suggested to be caused by extreme mantle metasomatism. Radiogenic (Sr-Nd-Hf-Pb) isotope and trace element compositions for mineral separates from MARID (clinopyroxene and amphibole) and PIC (clinopyroxene only) samples derived from Cretaceous kimberlites (Kimberley) and orangeites (Newlands) from South Africa are used here to examine the source(s) of mantle metasomatism. PIC clinopyroxene ( n = 4 ) is relatively homogeneous, with narrow ranges in initial isotopic composition (calculated to the emplacement age of the host Bultfontein kimberlite; 87Sr/86Sri: 0.7037-0.7041; ?Ndi: +3.0 to +3.6; ?Hfi: +2.2 to +2.5; 206Pb/204Pbi: 19.72-19.94) similar to kimberlite values. This is consistent with PIC rocks representing peridotites modified by intense metasomatic interaction with kimberlite melts. The MARID clinopyroxene ( n = 9 ) and amphibole separates ( n = 11 ) studied here display broader ranges in isotope composition (e.g., 87Sr/86Sri: 0.705-0.711; ?Ndi: ?11.0 to ?1.0; ?Hfi: ?17.9 to ?8.5; 206Pb/204Pbi: 17.33-18.72) than observed in previous studies of MARID rocks. The Nd-Hf isotope compositions of kimberlite-derived MARID samples fall below the mantle array (??Hfi between ?13.0 and ?2.4), a feature reported widely for kimberlites and other alkaline magmas. We propose that such displacements in MARID minerals result from metasomatic alteration of an initial “enriched mantle” MARID composition (i.e., 87Sr/86Sri = 0.711; ?Ndi = ?11.0; ?Hfi = ?17.9; and 206Pb/204Pbi = 17.3) by the entraining kimberlite magma (87Sr/86Sr ? i 0.704 ; ?Nd ? i + 3.3 ; ?Hf ? i + 2.3 ; 206Pb/204Pb ? i 19.7 ). A model simulating the flow of kimberlite magma through a mantle column, thereby gradually equilibrating the isotopic and chemical compositions of the MARID wall-rock with those of the kimberlite magma, broadly reproduces the Sr-Nd-Hf-Pb isotope compositions of the MARID minerals analysed here. This model also suggests that assimilation of MARID components could be responsible for negative ??Hfi values in kimberlites. The isotopic composition of the inferred initial MARID end-member, with high 87Sr/86Sr and low ?Nd, ?Hf, and 206Pb/204Pb, resembles those found in orangeites, supporting previous inferences of a genetic link between MARID-veined mantle and orangeites. The metasomatic agent that produced such compositions in MARID rocks must be more extreme than the EM-II mantle component and may relate to recycled material that experienced long-term storage in the lithospheric mantle.
DS201910-2301
2019
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D.Apatite geochemistry provides insights into the Late magmatic evolution of kimberlites.Goldschmidt2019, 1p. AbstractMantlemagmatism

Abstract: The late evolution of kimberlite magmas, i.e., during and following emplacement into the upper crust, remains a controversial aspect of kimberlite petrogenesis. Likewise, it is unclear whether or not there is a link between melt composition and the emplacement mechanism of intrusive kimberlites (i.e., planar dykes/sills vs. irregular intrusions in the root zone of pipes). Resolving these issues is hampered by the absence of comparative studies of late-magmatic kimberlite phases (e.g., apatite, monticellite, mica) in dykes, sills, and root-zone intrusions from the same locality. Here we report petrographic and mineral-chemical results for groundmass phases in samples of dykes, sills, and root zone intrusions from the Kimberley kimberlites (South Africa). Early crystalised phases (e.g., olivine, spinel) in dykes/sills and root-zone intrusions have indistingushable compositions, and hence crystallised from similar primitive melts. Conversely, apatite major element compositions are variable and can discriminate dykes/sills (i.e., low and constant Sr, with increasing Si) from root zone intrusions (high but variable Sr, low and constant Si). The Sr depletion in root zone apatite is interpreted to represent fractional crystallisation of earlier apatite, perovskite, and calcite from a broadly similar parental melt. Silica enrichment of apatite from dykes/sills may be attributed to the coupled incorporation of CO32- and Si into the apatite structure, reflecting higher CO2 contents in the melts that formed dykes/sills. CO2 enrichment in the dykes/sills is consistent with petrographic obervations. Dykes/sills are enriched in carbonates, may contain dolomite, and are depleted in mica and monticellite compared to the groundmass of rootzone kimberlites. This suggests the melts parental to dykes/sills have a higher CO2/H2O ratio compared to those parental to root zone intrusions. These two distinct melt evolution paths cannot be due to crustal contamination before emplacement because the Sr-isotope compositions of latecrystallised carbonates are indistinguishable in dykes/sills and root-zone intrusions. We speculate that CO2 is better retained in dykes/sills due to a higher confining pressure (i.e., lack of breakthrough to the surface).
DS201910-2304
2019
Giuliani, A.Tovey, M., Giuliani, A., Phillips, D., Moss, S.What controls the explosive emplacement of the diamondiferous Diavik kimberlites? New insights from mineral chemistry and petrography of hypbyssal and pyroclastic samples.Goldschmidt2019, 1p. AbstractCanada, Northwest Territoriesdeposit - Diavik

Abstract: Kimberlites are mantle-derived, CO2 and H2O rich magmas that entrain abundant mantle material, including diamonds during rapid ascent to the surface. Most kimberlite magmas that reach the upper crust either erupt explosively or are emplaced as shallow hypabyssal intrusions. Catastrophic volatile exsolution, local geology and stress regimes, and interaction with external water are suggested as possible controls of magma explosivity. A full understanding of the processes promoting the explosive emplacement of kimberlite magmas has been hindered by common alteration and crustal contamination of pyroclastic kimberlites (PK). To address this issue, we have undertaken a detailed petrographic and mineral-chemical study of fresh pyroclastic and hypabyssal kimberlites (i.e. dykes either cross-cutting or isolated from volcanic pipes) from the Diavik Diamond Mine (Lac de Gras, Canada). Diavik kimberlites feature the same olivine compositions regardless of emplacement style. The cross-cutting kimberlite dykes (xHK) and pyroclastic kimberlites also feature the same chromite (i.e. liquidus spinel) compositions, and spinel evolution to indistinguishable magnesian ulvospinel-magnetite compositions. These results demonstrate that primitive melt compositions, and early magmatic evolutionary trends are the same for kimberlite melts that erupt explosively or those that are emplaced as shallow intrusions. The magmaclasts in PKs contain higher abundances of phlogopite, and lower contents of carbonate than the groundmass of xHKs suggesting higher H2O/CO2 ratios in the magmas that erupt explosively. This finding highlights divergence of the PK and xHK parental melt compositions after late spinel formation, which underpins explosive CO2 exsolution only in some magmas. While the causes of explosive volcanism remain uncertain, our study indicates that primitive melt composition has no significant influence on the emplacement style of kimberlites.
DS201910-2308
2019
Giuliani, A.Woodhead, J., Hergt, J., Giuliani, A., Maas, R., Philips, D., Pearson, D.G., Nowell, G.Kimberlites reveal 2.5-nillion year evolution of a deep, isolated mantle reservoir.Nature, Vol. 573, pp. 578-581.Mantlemelting

Abstract: The widely accepted paradigm of Earth's geochemical evolution states that the successive extraction of melts from the mantle over the past 4.5 billion years formed the continental crust, and produced at least one complementary melt-depleted reservoir that is now recognized as the upper-mantle source of mid-ocean-ridge basalts1. However, geochemical modelling and the occurrence of high 3He/4He (that is, primordial) signatures in some volcanic rocks suggest that volumes of relatively undifferentiated mantle may reside in deeper, isolated regions2. Some basalts from large igneous provinces may provide temporally restricted glimpses of the most primitive parts of the mantle3,4, but key questions regarding the longevity of such sources on planetary timescales—and whether any survive today—remain unresolved. Kimberlites, small-volume volcanic rocks that are the source of most diamonds, offer rare insights into aspects of the composition of the Earth’s deep mantle. The radiogenic isotope ratios of kimberlites of different ages enable us to map the evolution of this domain through time. Here we show that globally distributed kimberlites originate from a single homogeneous reservoir with an isotopic composition that is indicative of a uniform and pristine mantle source, which evolved in isolation over at least 2.5 billion years of Earth history—to our knowledge, the only such reservoir that has been identified to date. Around 200 million years ago, extensive volumes of the same source were perturbed, probably as a result of contamination by exogenic material. The distribution of affected kimberlites suggests that this event may be related to subduction along the margin of the Pangaea supercontinent. These results reveal a long-lived and globally extensive mantle reservoir that underwent subsequent disruption, possibly heralding a marked change to large-scale mantle-mixing regimes. These processes may explain why uncontaminated primordial mantle is so difficult to identify in recent mantle-derived melts.
DS201911-2575
2019
Giuliani, A.Woodhead, J., Hergt, J., Giuliani, A., Maas, R., Phillips, D., Pearson, D.G., Nowell, G.Kimberlites reveal 2.5 billion year evolution of a deep, isolated mantle reservoir.Nature , Vol. 573, pp. 578-581.Mantlediamond genesis

Abstract: The widely accepted paradigm of Earth's geochemical evolution states that the successive extraction of melts from the mantle over the past 4.5 billion years formed the continental crust, and produced at least one complementary melt-depleted reservoir that is now recognized as the upper-mantle source of mid-ocean-ridge basalts1. However, geochemical modelling and the occurrence of high 3He/4He (that is, primordial) signatures in some volcanic rocks suggest that volumes of relatively undifferentiated mantle may reside in deeper, isolated regions2. Some basalts from large igneous provinces may provide temporally restricted glimpses of the most primitive parts of the mantle3,4, but key questions regarding the longevity of such sources on planetary timescales—and whether any survive today—remain unresolved. Kimberlites, small-volume volcanic rocks that are the source of most diamonds, offer rare insights into aspects of the composition of the Earth’s deep mantle. The radiogenic isotope ratios of kimberlites of different ages enable us to map the evolution of this domain through time. Here we show that globally distributed kimberlites originate from a single homogeneous reservoir with an isotopic composition that is indicative of a uniform and pristine mantle source, which evolved in isolation over at least 2.5 billion years of Earth history—to our knowledge, the only such reservoir that has been identified to date. Around 200 million years ago, extensive volumes of the same source were perturbed, probably as a result of contamination by exogenic material. The distribution of affected kimberlites suggests that this event may be related to subduction along the margin of the Pangaea supercontinent. These results reveal a long-lived and globally extensive mantle reservoir that underwent subsequent disruption, possibly heralding a marked change to large-scale mantle-mixing regimes. These processes may explain why uncontaminated primordial mantle is so difficult to identify in recent mantle-derived melts.
DS201912-2779
2020
Giuliani, A.Fitzpayne, A., Prytulak, J., Giuliani, A., Hergt, J.Thallium isotope composition of phlogopite in kimberlite hosted MARID and PIC mantle xenoliths.Chemical Geology, Vol. 531, 14p. PdfMantlemetasomatism

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks are rare mantle xenoliths entrained by kimberlites. Their high phlogopite modes (15 to ?100 vol.%) and consequent enrichments in alkali metals and H2O suggest a metasomatic origin. Phlogopite also has high concentrations (>0.2 ?g/g) of thallium (Tl) relative to mantle abundances (<3 ng/g). Thallium isotope ratios have proven useful in tracing the input of Tl-rich materials, such as pelagic sediments and altered oceanic crust, to mantle sources because of their distinct isotopic compositions compared to the peridotitic mantle. This study presents the first Tl isotopic compositions of well-characterised phlogopite separates from MARID and PIC samples to further our understanding of their genesis. The PIC rocks in this study were previously interpreted as the products of kimberlite melt metasomatism, whereas the radiogenic and stable N-O isotope systematics of MARID rocks suggest a parental metasomatic agent containing a recycled component. The ?205Tl values of phlogopite in both PIC (-2.7 ± 0.8; 2 s.d., n = 4) and MARID samples (-2.5 ± 1.3; 2 s.d., n = 21) overlap with the estimated mantle composition (-2.0 ± 1.0). PIC phlogopite Tl contents (?0.4 ?g/g) are suggestive of equilibrium with kimberlite melts (0.1-0.6 ?g/g Tl), based on partitioning experiments in other silica-undersaturated melts. Kimberlite Tl-?205Tl systematics suggest their genesis does not require a recycled contribution: however, high temperature-altered oceanic crust cannot be ruled out as a component of the Kimberley kimberlites’ source. Mantle-like ?205Tl values in MARID samples also seem to contradict previous suggestions of a recycled contribution towards their genesis. Recycled components with isotopic compositions close to mantle values (e.g., high temperature-altered oceanic crust) are still permitted. Moreover, mass balance mixing models indicate that incorporation into the primitive mantle of 1-30% of a low temperature-altered oceanic crust + continental crust recycled component or 1-50% of continental crust alone could be accommodated by the Tl-?205Tl systematics of the MARID parental melt. This scenario is consistent with experimental evidence and existing isotopic data. One PIC phlogopite separate has an extremely light Tl isotopic composition of -9.9, interpreted to result from kinetic isotopic fractionation. Overall, phlogopite is the main host mineral for Tl in metasomatised mantle and shows a very restricted range in Tl isotopic composition, which overlaps with estimates of the mantle composition. These results strongly suggest that negligible high temperature equilibrium Tl isotopic fractionation occurs during metasomatism and reinforces previous estimates of the mantle’s Tl isotopic composition.
DS201912-2785
2019
Giuliani, A.Giuliani, A., Pearson, D.G.Kimberlites: from deep Earth to diamond mines. An introduction.Elements, Vol. 15, 6, pp.Mantlediamond genesis
DS202001-0016
2019
Giuliani, A.Holwell, D.A., Fiorentini, M., McDonald, I., Lu, Y., Giuliani, A., Smith, D.J., Keith, M., Locmelis, M.A metasomatized lithospheric mantle control on the metallogenic signature of post-subduction magmatism. ( Not specific to diamonds)Nature Communications, doi.org/10.1038/s41467-019-11065-4 pdf 10p.Mantlesubduction

Abstract: Ore deposits are loci on Earth where energy and mass flux are greatly enhanced and focussed, acting as magnifying lenses into metal transport, fractionation and concentration mechanisms through the lithosphere. Here we show that the metallogenic architecture of the lithosphere is illuminated by the geochemical signatures of metasomatised mantle rocks and post-subduction magmatic-hydrothermal mineral systems. Our data reveal that anomalously gold and tellurium rich magmatic sulfides in mantle-derived magmas emplaced in the lower crust share a common metallogenic signature with upper crustal porphyry-epithermal ore systems. We propose that a trans-lithospheric continuum exists whereby post-subduction magmas transporting metal-rich sulfide cargoes play a fundamental role in fluxing metals into the crust from metasomatised lithospheric mantle. Therefore, ore deposits are not merely associated with isolated zones where serendipitous happenstance has produced mineralisation. Rather, they are depositional points along the mantle-to-upper crust pathway of magmas and hydrothermal fluids, synthesising the concentrated metallogenic budget available.
DS202002-0173
2019
Giuliani, A.Dalton, H., Giuliani, A., O'Brien, H., Phillips, D., Hergt, J.The role of lithospheric heterogeneity on the composition of kimberlite magmas from a single field: the case of Kaavi-Kuopio, Finland.Lithos, in press available, 61p. PdfEurope, Finlanddeposit - Kaavi-Kuopio

Abstract: Kimberlites are complex, ‘hybrid’ igneous rocks because their parental magmas entrain abundant crust- and mantle-derived components that can be readily assimilated during ascent to surface. Recent studies of olivine zonation patterns have shown compositional relationships between xenocrystic cores and magmatic rims, suggesting that kimberlite melt compositions might be controlled by assimilation of mantle material during emplacement. However, the nature and extent to which this process, as well as assimilation of crustal material, influences melt compositions within single kimberlite fields remains unclear. To address this issue, we have conducted a comprehensive geochemical and petrographic investigation of kimberlites from eight pipes in the Kaavi-Kuopio field in Finland, which were emplaced on the southern margin of the Karelian craton during the Neoproterozoic (~550-600 Ma). While magmatic olivine rims are usually homogeneous in composition within and between kimberlites of a single cluster and field (e.g., Lac de Gras), the Kaavi-Kuopio kimberlites appear to represent a unique case where there are statistically significant differences between the average Mg# of olivine rims in different pipes (89.9 ± 0.2 to 88.5 ± 0.3). Importantly, the Mg# of magmatic olivine rims exhibit a strong correlation with the Mg# of their mantle-derived xenocrystic cores. Furthermore, the compositions of olivine cores and rims exhibit a robust relationship with those of magmatic spinel (e.g., Mg#, TiO2 contents). These geochemical variations also align with the mineralogy of the kimberlites: whereby abundances of phlogopite and oxides (e.g., spinel) are negatively correlated with olivine rim Mg#. The robust relationship between entrained and assimilated lithospheric mantle material (i.e. olivine cores) and magmatic components (i.e. olivine rims, spinel, and groundmass mineral abundance), combined with numerical modelling suggests that up to 10 wt% assimilation of lithospheric mantle material has modified the compositions of the Kaavi-Kuopio kimberlites. These new data are also consistent with significant variations in the lithospheric mantle composition of the Karelian craton beneath the closely spaced (<10 km) kimberlites. Finally, in addition to mantle assimilation, formation of Si-Fe-rich mica in some of the examined kimberlites might be linked to late-stage increases in oxygen fugacity potentially enhanced by crustal contamination. This study shows for the first time that variable assimilation of mantle and crustal material can generate significant variations in kimberlites derived from seemingly similar sources.
DS202002-0174
2019
Giuliani, A.Dalton, H., Giuliani, A., O'Brien, H., Phillips, D., Maas, R. Petrogenesis of a hybrid cluster of evolved kimberlites and ultramafic lamprophyres in the Kuusamo area, Finland. Kasma 45, Kasma 45 south, Kasma 47, Kalettomanpuro, Kattaisenvaara, Dike 15 and LampiJournal of Petrology, in press available, 79p. PdfEurope, Finlanddeposit - Kuusamo

Abstract: Kimberlites are often closely associated, both in time and space, with a wide variety of alkaline ultramafic rock types; yet the question of a genetic relationship between these rock types remains uncertain. One locality where these relationships can be studied within the same cluster is the Karelian craton in Finland. In this study we present the first petrographic, mineral and whole-rock geochemical results for the most recently discovered kimberlite cluster on this craton, which represents an example of the close spatial overlap of kimberlites with ultramafic lamprophyres. The Kuusamo cluster incorporates seven bodies (Kasma 45, Kasma 45 south, Kasma 47, Kalettomanpuro (KP), Kattaisenvaara (KV), Dike 15 and Lampi) distributed along a 60?km NE-SW corridor. Hypabyssal samples from KV, KP, Kasma 45 and Kasma 47 consist of altered olivine macrocrysts and microcrysts and phlogopite phenocrysts in a groundmass of perovskite, apatite, spinel, ilmenite, serpentine, and calcite. These petrographic features combined with mineral (e.g., Mg-rich ilmenite, Al-Ba-rich, Ti-Fe-poor mica) and whole-rock incompatible trace element compositions (La/Nb = 0.8 ± 0.1; Th/Nb = 0.07 ± 0.01; Nb/U = 66 ± 9) are consistent with these rocks being classified as archetypal kimberlites. These Kuusamo kimberlites are enriched in CaO and poor in MgO, which combined with the absence of chromite and paucity of olivine macrocrysts and mantle-derived xenocrysts (including diamonds), suggest derivation from differentiated magmas after crystal fractionation. Samples from Lampi share similar petrographic features, but contain mica with compositions ranging from kimberlitic (Ba-Al-rich cores) to those more typical of orangeites/lamproites (increasing Si-Fe, decreasing Al-Ti-Ba), and have higher bulk-rock SiO2 contents than the Kuusamo kimberlites. These features, combined with the occurrence of quartz and titanite in the groundmass, indicate derivation from a kimberlite magma that underwent considerable crustal contamination. This study shows that crustal contamination can modify kimberlites by introducing features typical of alkaline ultramafic rock types. Dike 15 represents a distinct carbonate-rich lithology dominated by phlogopite over olivine, with lesser amounts of titaniferous clinopyroxene and manganoan ilmenite. Phlogopite (Fe-Ti-rich) and spinel (high Fe2+/Fe2++Mg) compositions are also distinct from the other Kuusamo intrusions. The petrographic and geochemical features of Dike 15 are typical of ultramafic lamprophyres, specifically, aillikites. Rb-Sr dating of phlogopite in Dike 15 yields an age of 1178.8 ± 4.1?Ma (2?), which is considerably older than the ?750?Ma emplacement age of the Kuusamo kimberlites. This new age indicates significant temporal overlap with the Lentiira-Kuhmo-Kostomuksha olivine lamproites emplaced ?100?km to the southeast. It is suggested that asthenospheric aillikite magmas similar to Dike 15 evolved to compositions akin to the Karelian orangeites and olivine lamproites through interaction with and assimilation of MARID-like, enriched subcontinental lithospheric mantle. We conclude that the spatial coincidence of the Kuusamo kimberlites and Dike 15 is likely the result of exploitation of similar trans-lithospheric corridors.
DS202003-0366
2020
Giuliani, A.Tovey, M., Giuliani, A., Phillips, D., Moss, S.Controls on the explosive emplacement of diamondiferous kimberlites: new insights from hypabyssal and pyroclastic units in the Diavik mine, Canada.Lithos, in press available, 55p. PdfCanada, Northwest Territoriesdeposit - Diavik

Abstract: Kimberlites are mantle-derived magmas that either crystallise as hypabyssal intrusions, erupt explosively after rapid ascent to the surface, or less commonly form lava lakes and flows, thereby creating texturally distinct kimberlite units. Efforts to fully understand the processes responsible for the explosive eruption of kimberlite magmas have been hindered by the widespread alteration and crustal contamination of most volcaniclastic kimberlites. To address this issue, we have undertaken a detailed petrographic and mineral chemical study of fresh (i.e. minimally altered) pyroclastic and hypabyssal kimberlites (HK) from the ca. 55-56?Ma A154 North and South kimberlite pipes in the Diavik Mine (Lac de Gras, Canada). These localities host exceptionally fresh kimberlites and are therefore ideally suited to this study. Kimberlite emplacement at A154 North and South initiated with the intrusion of hypabyssal kimberlite (external dykes), and was followed by the explosive formation of kimberlite pipes and volcaniclastic kimberlite infill. Subsequent kimberlite magmas intruded the volcaniclastic kimberlite units forming multiple cross-cutting, internal dykes. The studied volcaniclastic units feature abundant rounded magmaclasts and massive textures, suggestive of primary deposits. These units are classified as pyroclastic kimberlites (PK). Pyroclastic and hypabyssal kimberlite units at Diavik exhibit subtle mineral compositional differences. Samples from both internal HK units and PK units feature identical compositions for liquidus olivine rims (Mg#?=?90.5?±?0.1 and 90.7?±?0.2, respectively), with a marginally lower Mg# of 90.2?±?0.2 in olivine rims from the external HK dykes. Similarly, early-formed chromite compositions are the same for internal HK and PK units (Cr#?=?79.1?±?3.4 and 78.3?±?5.7; Mg#?=?60.0?±?1.3 and 60.0?±?2.2), but, differ in the external HK units (Cr#?=?86.9?±?2.7; Mg#?=?52.8?±?1.9). The internal HK and PK units also exhibit lower carbonate contents than the internal HK units. These compositional differences indicate that the external dykes were probably derived from slightly different primitive melt compositions to those parental to the internal HK and PK units. Spinel evolutionary trends from chromite to magnesian ulv?spinel-magnetite (MUM) compositions (Fe3+#?=?47.2?±?5.8 and 49.7?±?9.3; Cr#?=?25.7?±?11.0 and 17.0?±?14.0 for MUM) are indistinguishable in internal HK and PK samples. These results demonstrate that the primitive melt compositions and early magmatic evolution processes are identical for the internal kimberlite units, regardless of whether the kimberlite melts erupted explosively or were emplaced as shallow intrusions. However, magmaclasts in the PK units contain higher abundances of phlogopite (<52 vol%) and lower quantities of carbonate (<4 vol%) than the groundmass of the hypabyssal kimberlite samples (<2 vol% and 25-65 vol%, respectively). This indicates that the explosively erupted magmas featured higher H2O/CO2 ratios. In contrast, abundant carbonates, including dolomite, in the internal HK samples indicate that CO2, and therefore low H2O/CO2 ratios, were retained during the emplacement of this magma, which likely prevented phlogopite crystallisation. Lower K and Rb whole-rock compositions for internal HK samples compared to PK samples, are attributed to the removal of these components in late-stage kimberlitic fluids, as indicated by hydrothermal alteration of the adjacent volcaniclastic kimberlite units. The above results clearly rule out variations in primitive melt composition and melt evolution trajectories as a primary control on the explosive behaviour of the kimberlite magmas at Diavik. Our study also emphasises how volatile loss resulting from different emplacement styles can have a profound effect on the whole-rock compositions and petrography of kimberlite units. Controls on kimberlite explosivity at Diavik are likely due to external factors, such as local stress regimes, the availability of groundwater (i.e. phreatomagmatism) and differing magma supply rates.
DS202004-0518
2020
Giuliani, A.Howarth, G.H., Giuliani, A.Contrasting types of miceaceous kimberlite-lamproite magmatism from the Man craton ( West Africa): new insights from petrography and mineral chemistry.Lithos, in press available 63p. PdfAfrica, Sierra Leone, Liberiadeposit - Tongo, Weasua

Abstract: Diamondiferous rock types worldwide are broadly divided into kimberlite and lamproite, the latter of which have unique characteristics in different regions and include carbonate-rich varieties (formerly orangeites/Group II kimberlites). Diamondiferous rocks in West Africa are typically micaceous and share petrographic, mineralogical, and geochemical characteristics with both kimberlites and lamproites. To further constrain the classification and petrogenesis of diamondiferous rocks worldwide and their variability between different cratonic regions, in this study we combine detailed petrographic observations with olivine, phlogopite, and spinel chemistry for hypabyssal samples from the Jurassic Tongo dike (Sierra Leone) and the Neoproterozoic Weasua cluster (Liberia). The Tongo dike contains macrocrysts of olivine and phlogopite in a groundmass of olivine, abundant phlogopite, spinel, perovskite, and apatite with a base of calcite, dolomite, and lesser serpentine. The phlogopite is characterised by concurrent FeO and Al2O3 enrichment, which is typical of kimberlites and unlike lamproites. These features and the kimberlite-like spinel compositions allow us to classify the Tongo samples as micaceous kimberlites. The Weasua rocks comprise macrocrysts of olivine in a groundmass of olivine, phlogopite, diopside (zoned towards aegirine-rich rims), spinel, perovskite, and apatite with a base of serpentine and less common calcite. The composition of Weasua phlogopite trends to significant FeO enrichment and Al2O3 depletion, i.e. towards tetraferriphlogopite. The enrichment in mica, phlogopite chemistry and presence of magmatic diopside indicates that these rocks are olivine lamproites. The populations of olivine macrocrysts and microcrysts at Tongo and Weasua are similar and characterised by distinct core and rim zones. Two distinct olivine core populations are observed. 1) forsterite-rich (Fo?>?90) olivine interpreted to reflect xenocrysts from typical mantle peridotites. Al-in-olivine thermometry suggests that these cores have P-T equilibration within diamond stability at Weasua and Tongo. 2) Al-, Ca- and Na- rich cores with P-T formation conditions extending beyond the mantle adiabat. These cores are interpreted to reflect metasomatic and thermal perturbation linked with the infiltration of kimberlite/lamproite melts in the deep lithosphere shortly before entrainment in the ascending magma. The olivine rims at Tongo and Weasua show limited variations in Fo contents at similar values of 88.9?±?0.8 for Tongo and 89.6?±?1.2 for Weasua, as well as similar minor and trace element concentrations. Thus, whereas the Tongo and Weasua rock types are classified as kimberlite and olivine lamproite, respectively, the olivine chemistry suggests a similar petrogenetic evolution.
DS202005-0725
2020
Giuliani, A.Castillo-Oliver, M., Giuliani, A., Griffin, W.L., Drsydale, Rn.New constraints on the source, composition, and post-emplacement modification of kimberlites from in situ C-O-Sr-isotope analyses of carbonates from the Benfontein sills ( South Africa).Contributions to Mineralogy and Petrology, in press available, 21p. PdfAfrica, South Africadeposit - Benfontein

Abstract: Primary carbonates in kimberlites are the main CO2 carriers in kimberlites and thus can be used to constrain the original carbon and oxygen-isotope composition of kimberlite melts and their deep mantle sources. However, the contribution of syn- and post-emplacement processes to the modification of the C-O-isotope composition of kimberlites is yet to be fully constrained. This study aims to shed new light on this topic through a detailed textural, compositional (major and trace elements), and in situ C-O-Sr isotopic characterisation of carbonates in the Benfontein kimberlite sills (Kimberley, South Africa). Our multi-technique approach not only reveals the petrographic and geochemical complexity of carbonates in kimberlites in unprecedented detail, but also allows identification of the processes that led to their formation, including: (1) magmatic crystallisation of Sr-rich calcite laths and groundmass; (2) crystallisation of late groundmass calcite from hydrothermal fluids; and (3) variable degrees of crustal contamination in carbonate-rich diapirs and secondary veins. These diapirs most likely resulted from a residual C-O-H fluid or carbonate melt with contributions from methane-rich fluids from the Dwyka shale wall rock, leading to higher 87Sr/86Sr and ?18O, but lower ?13C values than in pristine magmatic calcite. Before coalescing into the diapiric segregations, these fluids/melts also variably entrained early formed calcite laths and groundmass phases. Comparison between in situ and bulk-carbonate analyses confirms that O isotopic analyses of bulk carbonates from kimberlite rocks are not representative of the original isotopic signature of the kimberlite magma, whereas bulk C-isotope compositions are similar to those of the pristine magmatic carbonates. Calcite laths and most groundmass grains at Benfontein preserve isotopic values (?18O?=?6-8‰ and ?13C?=???4 to ??6‰), similar to those of unaltered carbonatites worldwide, which, therefore, probably correspond to those of their parental melts. This narrow range suggests kimberlite derivation from a mantle source with little contribution from recycled crustal material unless the recycled material had isotopic composition indistinguishable from typical mantle values.
DS202006-0950
2020
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D.Apatite compositions and groundmass mineralogy record divergent melt/fluid evolution trajectories in coherent kimberlites caused by differing emplacement mechanisms.Contributions to Mineralogy and Petrology, Vol. 175, 21p. PdfAfrica, South Africadeposit - Kimberley

Abstract: Kimberlites are pipe-like igneous bodies, consisting of a pyroclastic crater and diatreme, commonly underlain by coherent root-zone rocks, and with associated dyke/sill complexes. The processes that control the different modes of coherent kimberlite emplacement remain uncertain. In addition, late evolution of kimberlite melts during emplacement into the upper crust remains poorly constrained. Therefore, it is unclear whether there is a link between melt composition/evolution and the emplacement mechanism of coherent kimberlites (i.e. planar dykes/sills vs. irregular bodies in the root zone). An absence of comparative studies on late-stage magmatic phases across the different emplacement modes of coherent kimberlite from the same locality hamper resolution of these issues. Therefore, we report petrographic and mineral chemical data for groundmass apatite in samples of dyke, sill, and root-zone kimberlites from the Kimberley cluster (South Africa). Early crystallised phases (olivine, spinel, Mg-ilmenite) in dyke/sill and root-zone kimberlites have indistinguishable compositions, and hence crystallised from similar primitive melts. Conversely, apatite compositions are generally distinct in dyke/sill (low Sr, high and variable Si) and root-zone kimberlites (high and variable Sr, low Si). The Si enrichment of apatite in dykes/sills is attributed to the coupled incorporation of CO32? and SiO44? for PO43?, reflecting higher CO2 contents in their parental melts, and potentially higher Si contents due to the preferential crystallisation of carbonates over mica/monticellite. The low Sr contents of apatite in dyke/sill kimberlites reflect equilibrium with a (kimberlite) melt (i.e. DSr is close to unity for carbonate and silicate melts), whereas the higher Sr contents of apatite in root-zone kimberlites require crystallisation from, or overprinting by a H2O?±?CO2 fluid (significantly higher DSr). The relative enrichment of CO2 in kimberlite dykes/sills is evident from the abundance of carbonates, the presence of mesostasis dolomite and calcite phenocrysts in some samples, and concomitant reduced proportions of other groundmass phases (e.g. serpentine, mica, monticellite). During late alteration of kimberlite dykes/sills, monticellite is typically replaced by carbonates, whereas olivine and pleonaste are relatively stable, indicating the melts which form dykes/sills evolve to higher CO2/H2O ratios. It is unlikely that these two distinct evolutionary paths were caused by crustal contamination before or during near surface magma emplacement, because crustal assimilation is not recorded in the O and Sr isotopic composition of late crystallising olivine rinds or carbonates, respectively. We suggest that higher concentrations of CO2 are retained in kimberlite dykes/sills due to higher confining pressures (i.e. lack of breakthrough to the surface). In contrast, exsolution of CO2 from root-zone kimberlites increased melt H2O/CO2 ratios and promoted the crystallisation of mica and monticellite at the expense of dolomite and calcite. Apatite compositions have the potential to aid in the discrimination of kimberlites from lamproites (higher LREE, Sr, F, and S, lower Si contents) and carbonatites (higher LREE, F, Cl and S, lower Fe contents). However, the compositions of kimberlitic apatite overlap those from aillikites, probably due to similar late-stage melt compositions.
DS202007-1132
2020
Giuliani, A.Choi, F.M., Fiorentini, M.L., Giuliani, A., Foley, S.F., Maas, R., Taylor, W.R.Subduction related tetrogenesis of late Archean calc-alkaline lamprophyres in the Yilgarn craton ( Western Australia).Precambrian Research, Vol. 338, 105550Australialamprophyres

Abstract: We present a comprehensive petrographic, mineralogical and geochemical study of calc-alkaline lamprophyres (CAL) from the Archean Yilgarn Craton, Western Australia. Previous studies have shown that the emplacement age of CAL from the Eastern Goldfields Superterrane of the Yilgarn Craton is ~2684 to ~2640 Ma. A new Rb/Sr mica age for a CAL sample in the Western Yilgarn is ~2070 Ma. Both Archean and Proterozoic CAL analysed in this study display porphyritic textures and contain phenocrysts of amphibole, minor clinopyroxene and biotite in a fine-grained groundmass dominated by feldspar. High MgO, Ni and Cr abundances (up to 11.9 wt%, 373 and 993 ppm. respectively) are consistent with derivation of primitive magmas from a mantle source. Enrichment in H2O, reflected in the abundance of magmatic amphibole and mica, combined with high whole-rock LILE, Th/Yb ratios and negative Nb-Ta anomalies in trace element patterns are consistent with a source that was metasomatised by hydrous fluids analogous to those generated by Phanerozoic subduction-related processes. Chondritic ?Nd and ?Hf signatures and Archean mantle-like Sr isotope signatures of the Late Archean CAL indicate that the fluid metasomatism required to explain their volatile and trace-element enriched composition shortly preceded partial melting (i.e. there was insufficient time to develop enriched radiogenic isotopic signatures). The concurrence of apparently juvenile radiogenic isotopes and fluid-related trace element compositions requires a geodynamic scenario whereby dehydration of a subducted slab triggered metasomatism of the overlying mantle wedge. Our findings therefore support a subduction setting at ~2.6-2.7 Ga along the eastern margin of the Yilgarn Craton. The CAL from the Western Yilgarn have similar compositions but enriched Sr-Nd-Hf isotopes compared to those in the Eastern Goldfields Superterrane. This signature is consistent with melting of lithospheric mantle domains previously enriched by subduction-related metasomatism. Hence, our study suggests the presence of a subduction setting in the Western Yilgarn during the Archean, which is consistent with previous geodynamic reconstructions. However, the geodynamic trigger for the early Proterozoic event that generated CAL magmatism in the Western Yilgarn is currently unclear.
DS202007-1140
2020
Giuliani, A.Fitzpayne, A., Giuliani, A., Hergt, J., Woodhead, J.D., Maas, R.Isotopic analyses of clinopyroxene demonstrate the effects of mantle metasomatism upon the lithospheric mantle.Lithos, in press available, 77p. PdfAfrica, South Africadeposit - Kimberley

Abstract: The trace element and radiogenic isotope systematics of clinopyroxene have frequently been used to characterise mantle metasomatic processes, because it is the main host of most lithophile elements in the lithospheric mantle. To further our understanding of mantle metasomatism, both solution-mode Sr-Nd-Hf-Pb and in situ trace element and Sr isotopic data have been acquired for clinopyroxene grains from a suite of peridotite (lherzolites and wehrlites), MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside), and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks from the Kimberley kimberlites (South Africa). The studied mantle samples can be divided into two groups on the basis of their clinopyroxene trace element compositions, and this subdivision is reinforced by their isotopic ratios. Type 1 clinopyroxene, which comprises PIC, wehrlite, and some sheared lherzolite samples, is characterised by low Sr (~100-200 ppm) and LREE concentrations, moderate HFSE contents (e.g., ~40-75 ppm Zr; La/Zr < 0.04), and restricted isotopic compositions (e.g., 87Sr/86Sri = 0.70369-0.70383; ?Ndi = +3.1 to +3.6) resembling those of their host kimberlite magmas. Available trace element partition coefficients can be used to show that Type 1 clinopyroxenes are close to being in equilibrium with kimberlite melt compositions, supporting a genetic link between kimberlites and these metasomatised lithologies. Thermobarometric estimates for Type 1 samples in this study indicate equilibration depths of 135-160 km within the lithosphere, thus showing that kimberlite melt metasomatism is prevalent in the deeper part of the lithosphere beneath Kimberley. In contrast, Type 2 clinopyroxenes occur in MARID rocks and coarse granular lherzolites in this study, which derive from shallower depths (<135 km), and have higher Sr (~350-1000 ppm) and LREE contents, corresponding to higher La/Zr of > ~ 0.05. The isotopic compositions of Type 2 clinopyroxenes are more variable and extend from compositions resembling the “enriched mantle” towards those of Type 1 rocks (e.g., ?Ndi = ?12.7 to ?4.4). To constrain the source of these variations, in situ Sr isotope analyses of clinopyroxene were undertaken, including zoned grains in Type 2 samples. MARID and lherzolite clinopyroxene cores display generally radiogenic but variable 87Sr/86Sri values (0.70526-0.71177), which are correlated with Sr contents and La/Zr ratios, and which might be explained by the interaction between peridotite and melts from different enriched sources within the lithospheric mantle. Most notably, the rims of these Type 2 clinopyroxenes trend towards compositions similar to those of the host kimberlite and Type 1 clinopyroxene from PIC and wehrlites. These results are interpreted to represent clinopyroxene overgrowth during late-stage (shortly before/during entrainment) metasomatism by kimberlite magmas. Our study shows that a pervasive, alkaline metasomatic event caused MARID to be generated and harzburgites to be converted to lherzolite in the lithospheric mantle beneath the Kimberley area, which was followed by kimberlite metasomatism during Cretaceous magmatism. This latter event is the time at which discrete PIC, wehrlite, and sheared lherzolite lithologies were formed, and MARID and granular lherzolites were partly modified.
DS202007-1141
2020
Giuliani, A.Fitzpayne, A., Prytulak, J., Giuliani, A., Hergt, J.Thallium content and isotopic composition of phlogopite in mantle derived MARID and PIC rocks.Chemical Geology, Vol. 531, 119347Mantlegeochronology
DS202007-1142
2020
Giuliani, A.Giuliani, A., Pearson, D.G., Soltys, A., Dalton, H., Phillips, D., Foley, S.F., Lim, E.Kimberlite genesis from a common primary melt modified by lithospheric mantle assimilation.Science Advances, Vol. 6, eeaz0424Mantlemelting

Abstract: Quantifying the compositional evolution of mantle-derived melts from source to surface is fundamental for constraining the nature of primary melts and deep Earth composition. Despite abundant evidence for interaction between carbonate-rich melts, including diamondiferous kimberlites, and mantle wall rocks en route to surface, the effects of this interaction on melt compositions are poorly constrained. Here, we demonstrate a robust linear correlation between the Mg/Si ratios of kimberlites and their entrained mantle components and between Mg/Fe ratios of mantle-derived olivine cores and magmatic olivine rims in kimberlites worldwide. Combined with numerical modeling, these findings indicate that kimberlite melts with highly variable composition were broadly similar before lithosphere assimilation. This implies that kimberlites worldwide originated by partial melting of compositionally similar convective mantle sources under comparable physical conditions. We conclude that mantle assimilation markedly alters the major element composition of carbonate-rich melts and is a major process in the evolution of mantle-derived magmas.
DS202007-1179
2020
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D.Apatite compositions and groundmass mineralogy record divergent melt/fluid evolution trajectories in coherent kimberlites caused by differing emplacement mechanisms.Contributions to Mineralogy and Petrology, Vol. 175, 49 dor.org./10.1007 /s00410-020-01686-0Africa, South Africadeposit - Kimberley

Abstract: Kimberlites are pipe-like igneous bodies, consisting of a pyroclastic crater and diatreme, commonly underlain by coherent root-zone rocks, and with associated dyke/sill complexes. The processes that control the different modes of coherent kimberlite emplacement remain uncertain. In addition, late evolution of kimberlite melts during emplacement into the upper crust remains poorly constrained. Therefore, it is unclear whether there is a link between melt composition/evolution and the emplacement mechanism of coherent kimberlites (i.e. planar dykes/sills vs. irregular bodies in the root zone). An absence of comparative studies on late-stage magmatic phases across the different emplacement modes of coherent kimberlite from the same locality hamper resolution of these issues. Therefore, we report petrographic and mineral chemical data for groundmass apatite in samples of dyke, sill, and root-zone kimberlites from the Kimberley cluster (South Africa). Early crystallised phases (olivine, spinel, Mg-ilmenite) in dyke/sill and root-zone kimberlites have indistinguishable compositions, and hence crystallised from similar primitive melts. Conversely, apatite compositions are generally distinct in dyke/sill (low Sr, high and variable Si) and root-zone kimberlites (high and variable Sr, low Si). The Si enrichment of apatite in dykes/sills is attributed to the coupled incorporation of CO32? and SiO44? for PO43?, reflecting higher CO2 contents in their parental melts, and potentially higher Si contents due to the preferential crystallisation of carbonates over mica/monticellite. The low Sr contents of apatite in dyke/sill kimberlites reflect equilibrium with a (kimberlite) melt (i.e. DSr is close to unity for carbonate and silicate melts), whereas the higher Sr contents of apatite in root-zone kimberlites require crystallisation from, or overprinting by a H2O?±?CO2 fluid (significantly higher DSr). The relative enrichment of CO2 in kimberlite dykes/sills is evident from the abundance of carbonates, the presence of mesostasis dolomite and calcite phenocrysts in some samples, and concomitant reduced proportions of other groundmass phases (e.g. serpentine, mica, monticellite). During late alteration of kimberlite dykes/sills, monticellite is typically replaced by carbonates, whereas olivine and pleonaste are relatively stable, indicating the melts which form dykes/sills evolve to higher CO2/H2O ratios. It is unlikely that these two distinct evolutionary paths were caused by crustal contamination before or during near surface magma emplacement, because crustal assimilation is not recorded in the O and Sr isotopic composition of late crystallising olivine rinds or carbonates, respectively. We suggest that higher concentrations of CO2 are retained in kimberlite dykes/sills due to higher confining pressures (i.e. lack of breakthrough to the surface). In contrast, exsolution of CO2 from root-zone kimberlites increased melt H2O/CO2 ratios and promoted the crystallisation of mica and monticellite at the expense of dolomite and calcite. Apatite compositions have the potential to aid in the discrimination of kimberlites from lamproites (higher LREE, Sr, F, and S, lower Si contents) and carbonatites (higher LREE, F, Cl and S, lower Fe contents). However, the compositions of kimberlitic apatite overlap those from aillikites, probably due to similar late-stage melt compositions.
DS202008-1380
2020
Giuliani, A.Choi, E., Fiorentini, M.L., Giuliani, A., Foley, S.F., Maas, R., Taylor, W.R.Subduction related petrogenesis of late Archean calc-alkaline lamprophyres in the Yilgarn craton, western Australia.Precambrian Research, Vol. 338, 105550, 18p. PdfAustralialamprophyres

Abstract: We present a comprehensive petrographic, mineralogical and geochemical study of calc-alkaline lamprophyres (CAL) from the Archean Yilgarn Craton, Western Australia. Previous studies have shown that the emplacement age of CAL from the Eastern Goldfields Superterrane of the Yilgarn Craton is ~2684 to ~2640 Ma. A new Rb/Sr mica age for a CAL sample in the Western Yilgarn is ~2070 Ma. Both Archean and Proterozoic CAL analysed in this study display porphyritic textures and contain phenocrysts of amphibole, minor clinopyroxene and biotite in a fine-grained groundmass dominated by feldspar. High MgO, Ni and Cr abundances (up to 11.9 wt%, 373 and 993 ppm. respectively) are consistent with derivation of primitive magmas from a mantle source. Enrichment in H2O, reflected in the abundance of magmatic amphibole and mica, combined with high whole-rock LILE, Th/Yb ratios and negative Nb-Ta anomalies in trace element patterns are consistent with a source that was metasomatised by hydrous fluids analogous to those generated by Phanerozoic subduction-related processes. Chondritic ?Nd and ?Hf signatures and Archean mantle-like Sr isotope signatures of the Late Archean CAL indicate that the fluid metasomatism required to explain their volatile and trace-element enriched composition shortly preceded partial melting (i.e. there was insufficient time to develop enriched radiogenic isotopic signatures). The concurrence of apparently juvenile radiogenic isotopes and fluid-related trace element compositions requires a geodynamic scenario whereby dehydration of a subducted slab triggered metasomatism of the overlying mantle wedge. Our findings therefore support a subduction setting at ~2.6-2.7 Ga along the eastern margin of the Yilgarn Craton. The CAL from the Western Yilgarn have similar compositions but enriched Sr-Nd-Hf isotopes compared to those in the Eastern Goldfields Superterrane. This signature is consistent with melting of lithospheric mantle domains previously enriched by subduction-related metasomatism. Hence, our study suggests the presence of a subduction setting in the Western Yilgarn during the Archean, which is consistent with previous geodynamic reconstructions. However, the geodynamic trigger for the early Proterozoic event that generated CAL magmatism in the Western Yilgarn is currently unclear.
DS202008-1390
2020
Giuliani, A.Fitzpaynek, A., Giuliani, A., Magalhaes, N., Soltys, A., Fiorentini, M., Farquhar, J.The petrology and sulphur istopic composition of sulphide and sulphate in the Kimberley kimberlites.Goldschmidt 2020, 1p. AbstractAfrica, South Africadeposit - Kimberley

Abstract: The petrology and bulk-rock sulphur isotopic compositions of kimberlite samples from four localities (Bultfontein, De Beers, Kimberley, Wesselton) of the archetypal Kimberley cluster, South Africa, were used to investigate the origin(s) of S in kimberlites and gain insights into the occurrence of recycled crustal material in the source of Mesozoic kimberlites. The samples, which show variable degrees of alteration, are all hypabyssal and were derived from coherent root-zones as well as dykes and sills. Typical sulphide minerals are Cu-Fe-Ni-sulphides with less common pyrite, galena, sphalerite, and djerfisherite. They occur in a variety of textural associations, for example as groundmass phases, secondary inclusions in olivine, inclusions in matrix phases (e.g., phlogopite), or in carbonate-serpentine segregations. Barite is the most commonly observed sulphate phase. Bulk-sample ?34SVCDT values of sulphides in fresh kimberlites, which mostly do not contain barite, vary from - 2.0 to -5.7 ‰. Slightly altered kimberlite samples, in which sulphides were generally associated with serpentine, returned somewhat higher bulk-sulphide ?34SVCDT (-3.8 to +1.1 ‰). One sample from the Wesselton Water Tunnel Sills complex contains abundant barite and pyrite in its groundmass, with the latter having ?34SVCDT (+0.2 to +1.9 ‰) similar to altered kimberlites. Two further altered samples returned ?34SVCDT values (-10.1 to -13.0 ‰) that suggest a contribution from the local country rocks (Dwyka shale: ?34SVCDT from -10.2 to -10.5 ‰). All samples have near-zero ?33S values, suggesting that material displaying mass-independent fractionation has not played an important role. The negative ?34SVCDT values of fresh kimberlites from Kimberley suggest the involvement of recycled crustal material in their source, which is consistent with radiogenic isotope compositions. Overall, it appears that most kimberlitic sulphide S isotopic compositions can be explained by the action of a few typical magmatic/hydrothermal processes.
DS202008-1393
2020
Giuliani, A.Giuliani, A., Jackson, M.G., Fitzpayne, A.The role of FOZO-PREMA in kimberlite genesis. Goldschmidt 2020, 1p. AbstractMantlekimberlite

Abstract: FOZO-PREMA is an ubiquitous component of oceanic basalts and was originally defined by the convergence of Sr- Nd-Pb isotope trends of ocean island basalts (OIBs) from individual island-seamount chains [1]. FOZO-PREMA is also widespread in juvenile continental magmas, which argue for a global relevance of this component irrespective of the tectonic settings. Early studies proposed that FOZO-PREMA could be a physically discrete reservoir derived from depletion of primitive mantle based on the combination of geochemically depleted 143Nd/144Nd combined with elevated 3He/4He ratios [2]. Conversely, later models showed that isotopic compositions spanning the FOZO-PREMA field can be obtained by mixing recycled oceanic crust and mantle material previously depleted by crust extraction [3]. Kimberlites can provide a new perspective on this debate because a recent study of the Nd and Hf isotope compositions of kimberlite through time shows that these magmas sample a deep, long-lived, homogeneous reservoir, which might contain remnants of early Earth differentiation processes [4]. We critically review the Sr, Nd and Hf isotope compositions of kimberlites that were emplaced from ~2.1 Ga. After screening kimberlite isotopic data for the effects of lithospheric contamination and secondary alteration, we show that kimberlites through time have been derived from a mantle source with FOZO-PREMA composition. This observation makes it unlikely that FOZO-PREMA derives from continuous mixing of depleted and recycled components because the composition of subducted lithologies, pressure and temperature conditions in subduction zones, and temperature and oxygen fugacity conditions of the convective mantle have changed throughout Earth history. We therefore conclude that FOZO-PREMA is a long-lived component of Earth’s mantle, which must have existed for at least the last 2.1 Ga, the wider implications of which will be discussed.
DS202008-1452
2020
Giuliani, A.Tovey, M., Giuliani, A., Phillips, D., Sarkar, C., Pearson, D.G., Nowicki, T., Carlson, J.Decoupling of kimberlite source and primitive melt compositions.Goldschmidt 2020, 1p. AbstractSouth America, Brazil, Africa, South Africa, Canada, Northwest Territoriesgeochronology

Abstract: Kimberlites emplaced since ~2 Ga show Nd and Hf isotopic compositions that follow a remarkably consistent linear evolution [1]. However, kimberlites emplaced <200 Ma within a few thousand kilometers of the western paleo-margin of Pangea (i.e. Brazil, southern Africa, and Lac de Gras in western Canada) deviate towards more enriched Nd and Hf isotopic compositions possibly due to contribution by recycled crustal material, introduced to the deep kimberlite source via subduction [1]. To address this anomaly further we have compared new and existing geochronological and Nd isotopic data for 28 kimberlites from Lac de Gras (LDG; ca. 47 - 75 Ma) with their olivine and spinel mineral chemistries. Olivine grains typically include mantle-derived xenocrystic cores (Mg# = 83.5-94.2) overgrown by magmatic rims with relatively constant Mg# values. Olivine rims and chromite are the first magmatic phases to crystallise from kimberlite and can be used as proxies for primitive melt compositions. The average Mg# of olivine cores from each kimberlite is positively correlated with average olivine rim Mg#, suggesting that assimilation of heterogeneous lithospheric mantle contributed to the primitive melt compositions. The ?Nd(i) values from whole-rock and perovskite from LDG kimberlites vary between -3.4 and -0.4 that are negatively correlated with their emplacement ages. This correlation is indicative of an evolving kimberlite source which may have resulted from a progressively lower contribution of recycled material. No systematic relationships were observed between olivine rim or chromite compositions and age or Nd isotopic composition. This observation highlights decoupling between kimberlite source evolution and primitive melt compositions due to the combined effects of crustal recycling in the kimberlite source and lithospheric mantle assimilation during kimberlite ascent.
DS202009-1664
2020
Giuliani, A.Soltys, A., Giuliani, A., Phillips, D., Kamenetsky, V.S.Kimberlite metasomatism of the lithosphere and the evolution of olivine in carbonate rich melts - evidence from the Kimberley kimberlites ( South Africa).Journal of Petrology, in press available, 90p. PdfAfrica, South Africadeposit - Kimberley

Abstract: Olivine is the most abundant phase in kimberlites and is stable throughout most of the crystallization sequence, thus providing an extensive record of kimberlite petrogenesis. To better constrain the composition, evolution, and source of kimberlites we present a detailed petrographic and geochemical study of olivine from multiple dyke, sill, and root zone kimberlites in the Kimberley cluster (South Africa). Olivine grains in these kimberlites are zoned, with a central core, a rim overgrowth, and occasionally an external rind. Additional ‘internal’ and ‘transitional’ zones may occur between the core and rim, and some samples of root zone kimberlites contain a late generation of high-Mg olivine in cross-cutting veins. Olivine records widespread pre-ascent (proto-)kimberlite metasomatism in the mantle including the following features: (1) relatively Fe-rich (Mg# <89) olivine cores interpreted to derive from the disaggregation of kimberlite-related megacrysts (20?% of cores); (2) Mg-Ca-rich olivine cores (Mg# >89; >0•05?wt% CaO) suggested to be sourced from neoblasts in sheared peridotites (25?% of cores); (3) transitional zones between cores and rims probably formed by partial re-equilibration of xenocrysts (now cores) with a previous pulse of kimberlite melt (i.e. compositionally heterogeneous xenocrysts); (4) olivine from the Wesselton water tunnel sills, internal zones (I), and low-Mg# rims, which crystallized from a kimberlite melt that underwent olivine fractionation and stalled within the shallow lithospheric mantle. Magmatic crystallization begins with internal olivine zones (II), which are common but not ubiquitous in the Kimberley olivine. These zones are euhedral, contain rare inclusions of chromite, and have a higher Mg# (90•0 ± 0•5), NiO, and Cr2O3 contents, but are depleted in CaO compared with the rims. Internal olivine zones (II) are interpreted to crystallize from a primitive kimberlite melt during its ascent and transport of olivine toward the surface. Their compositions suggest assimilation of peridotitic material (particularly orthopyroxene) and potentially sulfides prior to or during crystallization. Comparison of internal zones (II) with liquidus olivine from other mantle-derived carbonate-bearing magmas (i.e. orangeites, ultramafic lamprophyres, melilitites) shows that low (100×) Mn/Fe (?1•2), very low Ca/Fe (?0•6), and moderate Ni/Mg ratios (?1•1) appear to be the hallmarks of olivine in melts derived from carbonate-bearing garnet-peridotite sources. Olivine rims display features indicative of magmatic crystallization, which are typical of olivine rims in kimberlites worldwide; that is, primary inclusions of chromite, Mg-ilmenite and rutile, homogeneous Mg# (88•8 ± 0•3), decreasing Ni and Cr, and increasing Ca and Mn. Rinds and high-Mg olivine are characterized by extreme Mg-Ca-Mn enrichment and Ni depletion, and textural relationships indicate that these zones represent replacement of pre-existing olivine, with some new crystallization of rinds. These zones probably precipitated from evolved, oxidized, and relatively low-temperature kimberlite fluids after crustal emplacement. In summary, this study demonstrates the utility of combined petrography and olivine geochemistry to trace the evolution of kimberlite magmatic systems from early metasomatism of the lithospheric mantle by (proto-)kimberlite melts, to crystallization at different depths en route to surface, and finally late-stage deuteric or hydrothermal fluid alteration after crustal emplacement.
DS202102-0173
2020
Giuliani, A.Aulbach, S., Giuliani, A., Fiorentini, M.L., Baumgartner, R.J., Davard, D., Kamenetsky, V.S., Caruso, S., Danyushevsky, L.V., Powell, W., Griffin, W.L.Siderophile and chalcophile elements in spinels, sulphides and native Ni in strongly metasomatised xenoliths from the Bultfontein kimberlite (South Africa).Lithos, doi.org/10.1016/ jlithos.2020.105880, 26p. PdfAfrica, South Africadeposit - Bultfontein

Abstract: The metasomatised continental mantle may play a key role in the generation of some ore deposits, in particular mineral systems enriched in platinum-group elements (PGE) and Au. The cratonic lithosphere is the longest-lived potential source for these elements, but the processes that facilitate their pre-concentration in the mantle and their later remobilisation to the crust are not yet well-established. Here, we report new results on the petrography, major-element, and siderophile- and chalcophile-element composition of native Ni, base metal sulphides (BMS), and spinels in a suite of well-characterised, highly metasomatised and weakly serpentinised peridotite xenoliths from the Bultfontein kimberlite in the Kaapvaal Craton, and integrate these data with published analyses. Pentlandite in polymict breccias (failed kimberlite intrusions at mantle depth) has lower trace-element contents (e.g., median total PGE 0.72 ppm) than pentlandite in phlogopite peridotites and Mica-Amphibole-Rutile-Ilmenite-Diopside (MARID) rocks (median 1.6 ppm). Spinel is an insignificant host for all elements except Zn, and BMS and native Ni account for typically <25% of the bulk-rock PGE and Au. High bulk-rock Te/S suggest a role for PGE-bearing tellurides, which, along with other compounds of metasomatic origin, may host the missing As, Ag, Cd, Sb, Te and, in part, Bi that are unaccounted for by the main assemblage. The close spatial relationship between BMS and metasomatic minerals (e.g., phlogopite, ilmenite) indicates that the lithospheric mantle beneath Bultfontein was resulphidised by metasomatism after initial melt depletion during stabilisation of the cratonic lithosphere. Newly-formed BMS are markedly PGE-poor, as total PGE contents are <4.2 ppm in pentlandite from seven samples, compared to >26 ppm in BMS in other peridotite xenoliths from the Kaapvaal craton. This represents a strong dilution of the original PGE abundances at the mineral scale, perhaps starting from precursor PGE alloy and small volumes of residual BMS. The latter may have been the precursor to native Ni, which occurs in an unusual Ni-enriched zone in a harzburgite and displays strongly variable, but overall high PGE abundances (up to 81 ppm). In strongly metasomatised peridotites, Au is enriched relative to Pd, and was probably added along with S. A combination of net introduction of S, Au +/? PGE from the asthenosphere and intra-lithospheric redistribution, in part sourced from subducted materials, during metasomatic events may have led to sulphide precipitation at ~80-120 km beneath Bultfontein. This process locally enhanced the metallogenic fertility of this lithospheric reservoir. Further mobilisation of the metal budget stored in these S-rich domains and upwards transport into the crust may require interaction with sulphide-undersaturated melts that can dissolve sulphides along with the metals they store.
DS202102-0175
2020
Giuliani, A.Blanks, D.E., Holwell, D.A., Fiorentini, M.L., Moroni, M., Giuliani, A., Tassara, S., Gonzales-Jiminez, J.M., Boyce, A.J., Ferrari, E.Fluxing of mantle carbon as a physical agent for metallogenic fertilization of the crust.Nature Communications, doi.org/10.1038/ s41467-020-18157-6 11p. Pdf Mantlecarbon

Abstract: Magmatic systems play a crucial role in enriching the crust with volatiles and elements that reside primarily within the Earth’s mantle, including economically important metals like nickel, copper and platinum-group elements. However, transport of these metals within silicate magmas primarily occurs within dense sulfide liquids, which tend to coalesce, settle and not be efficiently transported in ascending magmas. Here we show textural observations, backed up with carbon and oxygen isotope data, which indicate an intimate association between mantle-derived carbonates and sulfides in some mafic-ultramafic magmatic systems emplaced at the base of the continental crust. We propose that carbon, as a buoyant supercritical CO2 fluid, might be a covert agent aiding and promoting the physical transport of sulfides across the mantle-crust transition. This may be a common but cryptic mechanism that facilitates cycling of volatiles and metals from the mantle to the lower-to-mid continental crust, which leaves little footprint behind by the time magmas reach the Earth’s surface.
DS202102-0188
2020
Giuliani, A.Fiorentini, M.L., O'Neill, C., Giuliani, A., Choi, E., Maas, R., Pirajno, F., Foley, S.Bushveld superplume drove Proterozoic magmatism and metallogenesis in Australia. Nature Scientific Reports, doi.org/10.1038/ s41598-020-76800-0 10p. PdfAustralia, Africa, South Africaalkaline magmatism

Abstract: Large-scale mantle convective processes are commonly reflected in the emplacement of Large Igneous Provinces (LIPs). These are high-volume, short-duration magmatic events consisting mainly of extensive flood basalts and their associated plumbing systems. One of the most voluminous LIPs in the geological record is the ~?2.06 billion-year-old Bushveld Igneous Complex of South Africa (BIC), one of the most mineralised magmatic complexes on Earth. Surprisingly, the known geographic envelope of magmatism related to the BIC is limited to a series of satellite intrusions in southern Africa and has not been traced further afield. This appears inconsistent with the inferred large size of the BIC event. Here, we present new radiometric ages for alkaline magmatism in the Archean Yilgarn Craton (Western Australia), which overlap the emplacement age of the BIC and indicate a much more extensive geographic footprint of the BIC magmatic event. To assess plume involvement at this distance, we present numerical simulations of mantle plume impingement at the base of the lithosphere, and constrain a relationship between the radial extent of volcanism versus time, excess temperature and plume size. These simulations suggest that the thermal influence of large plume events could extend for thousands of km within a few million years, and produce widespread alkaline magmatism, crustal extension potentially leading to continental break-up, and large ore deposits in distal sectors. Our results imply that superplumes may produce very extensive and diverse magmatic and metallogenic provinces, which may now be preserved in widely-dispersed continental blocks.
DS202102-0193
2020
Giuliani, A.Giuliani, A., Jackson, M.G., Fitzpayne, A., Dalton, H.Remnants of early Earth differentiation in the deepest mantle-derived lavas. ( kimberlite source)PNAS, Vol. 118, 1 e201521118, 9p. PdfMantlekimberlite

Abstract: The noble gas isotope systematics of ocean island basalts suggest the existence of primordial mantle signatures in the deep mantle. Yet, the isotopic compositions of lithophile elements (Sr, Nd, Hf) in these lavas require derivation from a mantle source that is geochemically depleted by melt extraction rather than primitive. Here, this apparent contradiction is resolved by employing a compilation of the Sr, Nd, and Hf isotope composition of kimberlites—volcanic rocks that originate at great depth beneath continents. This compilation includes kimberlites as old as 2.06 billion years and shows that kimberlites do not derive from a primitive mantle source but sample the same geochemically depleted component (where geochemical depletion refers to ancient melt extraction) common to most oceanic island basalts, previously called PREMA (prevalent mantle) or FOZO (focal zone). Extrapolation of the Nd and Hf isotopic compositions of the kimberlite source to the age of Earth formation yields a 143Nd/144Nd-176Hf/177Hf composition within error of chondrite meteorites, which include the likely parent bodies of Earth. This supports a hypothesis where the source of kimberlites and ocean island basalts contains a long-lived component that formed by melt extraction from a domain with chondritic 143Nd/144Nd and 176Hf/177Hf shortly after Earth accretion. The geographic distribution of kimberlites containing the PREMA component suggests that these remnants of early Earth differentiation are located in large seismically anomalous regions corresponding to thermochemical piles above the core-mantle boundary. PREMA could have been stored in these structures for most of Earth’s history, partially shielded from convective homogenization.
DS202103-0421
2021
Giuliani, A.Wang, C., Zhang, Z., Giuliani, A., Cheng, Z., Liu, B., Kong, W.Geochemical and O-C-Sr-Nd isotopic constraints on the petrogenetic link between aillikites and carbonatites in the Tarim Large Igneous Province.Journal of Petrology, in press available 69p. PdfChinacarbonatites

Abstract: Aillikites are carbonate-rich ultramafic lamprophyres often associated with carbonatites. Despite their common field relationships, the petrogenetic links, if any, between aillikites and carbonatites remain controversial. To address this question, this study reports the results of a detailed geochemical and isotopic examination of the Permian Wajilitag aillikites in the northwestern Tarim large igneous province, including bulk-rock major-, trace-element and Sr-Nd isotope compositions, olivine major- and trace-element and (in-situ secondary ion mass spectrometry) oxygen isotope compositions, oxygen isotope data for clinopyroxene separates, and bulk-carbonate C-O isotopic analyses. Olivine in the aillikites occurs in two textural types: (i) microcrysts, 0.3-5?mm; and (ii) macrocrysts, 0.5-2.5?cm. The microcrysts exhibit well-defined linear correlations between Fo (79-89), minor and trace elements (e.g., Ni?=?1304-3764??g/g and Mn?=?1363-3042??g/g). In contrast, the olivine macrocrysts show low Fo79-81, Ni (5.3-442??g/g) and Ca (477-1018??g/g) and very high Mn (3418-5123??g/g) contents, and are displaced from the compositional trend of the microcrysts. The microcrysts are phenocrysts crystallized from the host aillikite magmas. Conversely, the lack of mantle-derived xenoliths in these aillikites suggests that the macrocrysts probably represent cognate crystals (i.e., antecrysts) that formed from earlier, evolved aillikite melts. Olivine phenocrysts in the more primitive aillikite dykes (Dyke 1) have relatively higher Fo82-89 and mantle-like oxygen isotope values, whereas those in the more evolved dykes (Dyke 2 and 3) exhibit lower Fo79-86 and oxygen isotope values that trend toward lower than mantle ?18O values. The decreasing ?13C values of carbonate from Dyke 1 through to Dyke 2 and 3, coupled with the indistinguishable Sr-Nd isotopes of these dykes, suggest that the low ?18O values of olivine phenocrysts in Dyke 2 and 3 resulted from carbonate melt/fluid exsolution from a common progenitor melt. These lines of evidence combined with the overlapping emplacement ages and Sr-Nd isotope compositions of the aillikites and carbonatites in this area suggest that these exsolved carbonate melts probably contributed to the formation of the Tarim carbonatites thus supporting a close petrogenetic relationship between aillikites and carbonatites.
DS202104-0578
2020
Giuliani, A.Giuliani, A., Jackson, M.G., Fitzpayne, A., Dalton, H.Remnants of early Earth differentiation in the deepest mantle-derived lavas.Proceedings of the National Academy of Sciences PNAS, Vol. 118, 1 e201521118 9p. PdfMantlekimberlite

Abstract: The noble gas isotope systematics of ocean island basalts suggest the existence of primordial mantle signatures in the deep mantle. Yet, the isotopic compositions of lithophile elements (Sr, Nd, Hf) in these lavas require derivation from a mantle source that is geochemically depleted by melt extraction rather than primitive. Here, this apparent contradiction is resolved by employing a compilation of the Sr, Nd, and Hf isotope composition of kimberlites—volcanic rocks that originate at great depth beneath continents. This compilation includes kimberlites as old as 2.06 billion years and shows that kimberlites do not derive from a primitive mantle source but sample the same geochemically depleted component (where geochemical depletion refers to ancient melt extraction) common to most oceanic island basalts, previously called PREMA (prevalent mantle) or FOZO (focal zone). Extrapolation of the Nd and Hf isotopic compositions of the kimberlite source to the age of Earth formation yields a 143Nd/144Nd-176Hf/177Hf composition within error of chondrite meteorites, which include the likely parent bodies of Earth. This supports a hypothesis where the source of kimberlites and ocean island basalts contains a long-lived component that formed by melt extraction from a domain with chondritic 143Nd/144Nd and 176Hf/177Hf shortly after Earth accretion. The geographic distribution of kimberlites containing the PREMA component suggests that these remnants of early Earth differentiation are located in large seismically anomalous regions corresponding to thermochemical piles above the core-mantle boundary. PREMA could have been stored in these structures for most of Earth’s history, partially shielded from convective homogenization.
DS202106-0929
2021
Giuliani, A.Choi, E., Fiorentini, M.L., Giuliani, A., Foley, S.F., Maas, R., Graham, S.Petrogenesis of Proterozoic alkaline ultramafic rocks in the Yilgarn Craton, western Australia.Gondwana Research, Vol. 93, pp. 197-217. pdfAustraliacarbonatites

Abstract: The Yilgarn Craton and its northern margin contain a variety of petrogenetically poorly defined small-volume alkaline ultramafic rocks of Proterozoic age. This study documents the petrography, mineral and bulk-rock geochemistry and Nd-Hf-Sr-Pb isotope compositions of a selected suite of these rocks. They comprise ~2.03-2.06 Ga ultramafic lamprophyres (UML) and carbonatites from the Eastern Goldfields Superterrane (EGS), ~0.86 Ga UML from Norseman, and orangeites from the Earaheedy Basin, including samples from Jewill (~1.3 Ga), Bulljah (~1.4 Ga) and Nabberu (~1.8-1.9 Ga). The Proterozoic UML and carbonatites from the EGS and Norseman display very consistent chondritic to superchondritic Nd-Hf isotope compositions and trace-element ratios similar to modern OIBs, which are indicative of a common mantle source across this wide alkaline province. These Nd-Hf isotope compositions overlap with the evolution trends of global kimberlites through time, thus suggesting that this mantle source could be deep and ancient as that proposed for kimberlites. Conversely, the orangeites located in the Earaheedy Basin along the northern margin of the Yilgarn Craton display trace element signatures similar to subduction-related calc-alkaline magmas. Taken together with their highly enriched Sr-Nd-Hf isotope compositions, these characteristics indicate an ancient lithospheric mantle source, which was probably metasomatised by subduction-related fluids. As the ages of the Bulljah and Jewill orangeites overlap with the breakup of the Columbia supercontinent, it is proposed that orangeite magmatism was triggered by changes in plate stress conditions associated with this event. This study provides a comprehensive picture of the genesis of Proterozoic alkaline magmatism in the Yilgarn Craton, highlighting the complex tectono-magmatic evolution of this lithospheric block after its assembly in the Archean.
DS202107-1117
2021
Giuliani, A.Nakanishi, N., Giuliani, A., Carlson, R.W., Horan, M.F., Woodhead, J., Pearson, D.G., Walker, R.J.Tungsten-182 evidence for an ancient kimberlite source.PNAS, Vol. 118, no. 23, doi.org/10.1073/pnas .e2020680118 8p. PdfMantledeep source, genesis

Abstract: Globally distributed kimberlites with broadly chondritic initial 143Nd-176Hf isotopic systematics may be derived from a chemically homogenous, relatively primitive mantle source that remained isolated from the convecting mantle for much of the Earth’s history. To assess whether this putative reservoir may have preserved remnants of an early Earth process, we report 182W/184W and 142Nd/144Nd data for "primitive" kimberlites from 10 localities worldwide, ranging in age from 1,153 to 89 Ma. Most are characterized by homogeneous ?182W and ?142Nd values averaging ?5.9 ± 3.6 ppm (2SD, n = 13) and +2.7 ± 2.9 ppm (2SD, n = 6), respectively. The remarkably uniform yet modestly negative ?182W values, coupled with chondritic to slightly suprachondritic initial 143Nd/144Nd and 176Hf/177Hf ratios over a span of nearly 1,000 Mya, provides permissive evidence that these kimberlites were derived from one or more long-lived, early formed mantle reservoirs. Possible causes for negative ?182W values among these kimberlites include the transfer of W with low ?182W from the core to the mantle source reservoir(s), creation of the source reservoir(s) as a result of early silicate fractionation, or an overabundance of late-accreted materials in the source reservoir(s). By contrast, two younger kimberlites emplaced at 72 and 52 Ma and characterized by distinctly subchondritic initial 176Hf/177Hf and 143Nd/144Nd have ?182W values consistent with the modern upper mantle. These isotopic compositions may reflect contamination of the ancient kimberlite source by recycled crustal components with ?182W ? 0.
DS202112-1943
2021
Giuliani, A.Sarkar, S., Giuliani, A., Ghosh, S., Phillips, D.Petrogenesis of coeval lamproites and kimberlites from the Wajrakarur field, southern India: new insights from olivine compositions.Lithos, Vol. 406-407, 106524 13p. PdfIndiadeposit - Wajrakarur

Abstract: Olivine is one of the most abundant phases in kimberlites and cratonic lamproites, where it occurs as mantle-derived xenocrysts and magmatic phenocrysts or rims overgrowing xenocrystic cores, indicating its prevalence throughout most of the crystallisation sequence of these magmas. Thus, olivine can provide valuable insights into kimberlite and lamproite petrogenesis. Here, we present a detailed study of olivine compositional zoning in two lamproites (P2 and P12) of the Mesoproterozoic Wajrakarur kimberlite-lamproite field in southern India and use these data to propose a genetic link between lamproites and kimberlites in the region. Olivine macrocrysts (i.e., anhedral grains >1 mm) from the P2 and P12 intrusions are strongly zoned. Comparisons with olivine from mantle xenoliths worldwide demonstrate that the cores of olivine macrocrysts are xenocrysts derived from disaggregated mantle wall-rocks. The internal zones and overgrowth rims of olivine macrocrysts and the cores of olivine phenocrysts from P2 and P12 contain magmatic Mg-chromite and Ti-magnetite inclusions and hence crystallized from the host lamproite melt. These magmatic olivine zones show increasing Mg# (molar Mg/(Mg + Fe2+)), CaO and MnO contents with decreasing NiO. This reverse differentiation trend appears to be a characteristic feature of olivine in lamproites from the Wajrakarur field. To evaluate potential petrogenetic links between coeval lamproites and kimberlites from Wajrakarur, the composition of olivine xenocrysts (i.e., macrocryst cores) was compared with that of early crystallized olivine in P2, P12 and previously studied kimberlites and lamproites. The average Mg# of olivine macrocryst cores is directly correlated with the average Mg# of magmatic olivine in lamproites and kimberlites from Wajrakarur. Coupled with their indistinguishable Sr-Nd-Hf isotope compositions, these data suggest derivation of the Wajrakarur lamproites and kimberlites from a common source, The more Fe-rich composition of liquidus olivine in the Wajrakarur lamproites compared to coeval kimberlites suggests a higher degree of assimilation of metasomatised Fe-richer lithospheric mantle by the lamproites and provides a plausible explanation for the different petrological features of the Wajrakarur lamproites and kimberlites Our results suggest that cratonic lamproites can have a remarkably similar petrogenetic history to kimberlites.
DS202112-1957
2021
Giuliani, A.Xu, J-Y., Giuliani, A., Li, Q-L., Lu, K., Melgarejo, J.C., Griffin, W.L.Light oxygen isotopes in mantle-derived magmas reflect assimilation of sub-continental lithospheric mantle material.Nature Communications, 10.10.1038/s4167-021-266668-z 14p. PdfMantleolivine

Abstract: Oxygen isotope ratios in mantle-derived magmas that differ from typical mantle values are generally attributed to crustal contamination, deeply subducted crustal material in the mantle source or primordial heterogeneities. Here we provide an alternative view for the origin of light oxygen-isotope signatures in mantle-derived magmas using kimberlites, carbonate-rich magmas that assimilate mantle debris during ascent. Olivine grains in kimberlites are commonly zoned between a mantle-derived core and a magmatic rim, thus constraining the compositions of both mantle wall-rocks and melt phase. Secondary ion mass spectrometry (SIMS) analyses of olivine in worldwide kimberlites show a remarkable correlation between mean oxygen-isotope compositions of cores and rims from mantle-like 18O/16O to lower ‘crustal’ values. This observation indicates that kimberlites entraining low-18O/16O olivine xenocrysts are modified by assimilation of low-18O/16O sub-continental lithospheric mantle material. Interaction with geochemically-enriched domains of the sub-continental lithospheric mantle can therefore be an important source of apparently ‘crustal’ signatures in mantle-derived magmas.
DS202205-0723
2022
Giuliani, A.Tovey, M., Giuliani, A., Phillips, D., Nowicki, T., Pearson, D.G., Fedorchouk, Y., Russell, J.K.Controls on the emplacement style of coherent kimberlites in the Lac de Gras Field, Canada.Journal of Petrology, 10.1093/petrology/egac028/6553928 24p. pdf Canada, Northwest Territoriesdeposit - Lac de Gras

Abstract: In the Lac de Gras (LDG) kimberlite field, Northwest Territories, Canada, coherent kimberlites (CKs) occur as tabular dykes, pipe-shaped diatremes, and irregular bodies without well-defined geometries. Combining the morphology of CK bodies with the occurrence of fragmented olivine microcrysts allows distinction of four CK types at LDG: (1) dykes with no broken olivine; (2) CK without well-defined but probable sheet geometry and no broken olivine; (3) pipe-filling CK (pfCK) with abundant broken olivine and (4) pfCK with no broken olivine. These features suggest an intrusive origin for type 1 and, probably, type 2 CK; a high-energy extrusive emplacement for CK type 3 and a low-energy intrusive or extrusive emplacement for the CK type 4. Here, we compare petrographic and whole-rock, olivine and spinel compositional data for high-energy extrusive pfCK, low-energy pfCK and intrusive CK units to understand the factors controlling their variable emplacement styles. Extrusive CK contain more abundant groundmass phlogopite and monticellite, lower carbonate/silicate mineral abundance ratios and significantly lower dolomite and pleonaste-spinel abundances compared to intrusive CK. This indicates greater CO2 loss and higher H2O/CO2 in the melt phase for the extrusive CK during emplacement. Lower incompatible element concentrations in the extrusive CKs and different chromite Ti# and olivine rim Mg# indicate derivation from distinct primitive melt compositions. The extrusive CK feature higher ?Ndi and marginally higher ?Hfi compositions than the intrusive CK, pointing to derivation from distinct sources. These findings strongly imply that distinct primary melt compositions were largely responsible for the differences in emplacement styles of CK at LDG. Low-energy pfCKs have similar olivine rim Mg#, chromite Ti# and, hence, primitive melt compositions to the high-energy extrusive CK samples. Their marginally different emplacement styles may depend on local factors, such as changing stress regimes, or slightly different volatile concentrations. Both types of pfCK might reflect the waning stages of volcanic sequences resulting from the eruption of a segregated magma column that started with pipe excavation and the explosive emplacement of gas-rich magma (volcaniclastic kimberlite), followed by the less energetic emplacement of melt-rich magma (pfCK). This hypothesis underscores different primary melt compositions for dyke vs pipe-forming (and filling) kimberlites and hence a fundamental primary melt control on the explosivity of kimberlites.
DS202205-0729
2022
Giuliani, A.Wang, C., Zhang, Z., Giuliani, A., Cai, R., Cheng, Z., Liu, J.New insights into the mantle source of a large igneous province from highly siderophile element and Sr-Nd-Os isotope compositions of carbonate-rich ultramafic lamprophyres.Geochimica et Cosmochimica Acta, Vol. 326, pp. 77-96.Chinaallikites

Abstract: Despite being volumetrically minor components, carbonate-rich ultramafic magmas like aillikites represent good candidates to investigate the compositional variations in plume and/or lithospheric mantle sources because they represent low-degree melts which preferentially sample highly fusible components including recycled crustal material. To gain new insights into the composition of the plume-related magmas and, more broadly, the petrogenesis of ultramafic lamprophyres, we have undertaken the first comprehensive study of bulk rock and mineral (olivine and Ti-magnetite) highly siderophile element (HSE) abundances and Re-Os isotopes combined with in situ major-, trace-element and Sr-Nd isotope analyses of apatite and perovskite from the Permian Wajilitag aillikites of the Tarim large igneous province, China. The Wajilitag aillikites have high PPGE (Pt and Pd) contents relative to IPGE (Os, Ir and Ru), which can be ascribed to low-degree partial melting and/or fractionation of olivine and laurite. Measured 187Os/188Os ratios are moderately to highly radiogenic (0.186-0.313) with age-corrected ?Os values up to +113. In situ Sr and Nd isotope analyses of apatite phenocrysts (87Sr/86Sr(i) = 0.70349-0.70384; ?Nd(i) = +1.3 to +4.9) and fresh perovskite grains (87Sr/86Sr(i) = 0.70340-0.70390; ?Nd(i) = +1.3 to +3.8) exhibit limited variability both within and across samples from different aillikite dykes and the only volcanic pipe in the area. These Nd isotopic values resemble those from bulk-rock samples (?Nd(i) = +1.9 to +5.2), whereas Sr in apatite and perovskite extends to marginally less radiogenic values than the bulk-rock compositions (87Sr/86Sr(i) = 0.70362-0.70432). The moderately depleted Sr-Nd isotope compositions of magmatic apatite and perovskite, and the previously reported mantle-like C isotope values of these samples suggest that the aillikites and their carbon probably derived from a sub-lithospheric (plume) source with minimal contribution of deeply subducted material. Conversely, the radiogenic Os isotope compositions of the Tarim aillikites and separated minerals require some contribution from recycled crustal material in the plume source. Mass balance calculations suggest that the radiogenic Os isotopes and moderately depleted Sr-Nd isotopes can be reproduced by less than one third of eclogite component addition to a moderately depleted mantle source. We conclude that the combination of complementary isotopic systems can enlighten contributions from different components to mantle-derived magmas and, in this case, clarifies the occurrence of carbon-free subducted oceanic crust in the Tarim plume.
DS201707-1328
2017
Giuliani, A.M.Giuliani, A.M., Tappe, S., Rooney, T.O., McCoy-West, A.J., Yaxley, G.M., Mezger, K.Editorial: the role of intraplate magmas and their inclusions in Earth's mantle evolution.Chemical Geology, Vol. 455, pp. 1-5.Mantlemagmatism

Abstract: Carbon isotope compositions and the distribution of nitrogen and hydrogen in diamonds from 18 eclogites from Nurbinskaya kimberlites were studied in situ in polished plates. Cathodoluminescence images show that most of the diamonds have complex growth structures with distinctive cores, intermediate and rim zones. In some diamonds the cores display dissolution features, and intermediate growth zones are separated from the cores by narrow rounded oscillatory zones. At least three crystals show interrupted multistage diamond growth; variations in ? ¹³C of 2–3‰ occur across the contacts between distinct zones. Generally, ?¹³C within the diamond cores varies only by 1–2‰, in rare cases up to 3.3‰. ?¹³C values are usually lower in the intermediate zones and drop further towards the rims by up to 3‰. High-resolution SIMS profiles show that variations in ?¹³C across the diamond growth zones are sharp with no evidence of diffusive relaxation.
DS1990-0576
1990
Giuliani, G.Giuliani, G., Cheilletz, A., Zimmerman, J.L.The emplacement, geochemistry and petrogenesis of two central Morocco Hercynian granites. Geotectonic implicationsJournal of African Earth Sciences, Vol. 9, No. 3/4, pp. 617-629Moroccorare earth elements (REE) geochemistry, Granites
DS201412-0295
2014
Giuliani, G.Giuliani, G.Oxygen isotope and trace element evidence for the origin of sapphire and/or ruby in the Mbuyi-Mayi kimberlite ( FDC) and the Changle alkali basalt China.ima2014.co.za, AbstractAfrica, Democratic Republic of CongoDeposit - Mbuyi-Mayi
DS201412-0296
2014
Giuliani, G.Giuliani, G., Phillips, D., Maas, R., Woodhead, J.D., Kendrick, M.A., Greig, A., Armstrong, R.A., Chew, D., Kamenetsky, V.S., Fiorentini, M.I.LIMA U-Pb ages link lithospheric mantle metasomatism to Karoo magmatism beneath the Kimberley region, South Africa.Earth and Planetary Science Letters, Vol. 401, pp. 132-147.Africa, South AfricaKimberlite
DS201505-0235
2015
Giuliani, G.Giuliani, G.,Pivin, M., Fallick, A.E., Ohnenstetter, D., Song, Y., Demaiffe, D.Geochemical and oxygen isotope signatures of mantle corundum megacrysts from the Mbuji-Mayi kimberlite, Democratic Republic of Congo and the Changle alkali basalt, China.Comptes Rendus Geoscience, Vol. 347, 1, pp. 24-34.Africa, Democratic Republic of Congo, ChinaDeposit - Mbuji-Mayi
DS201607-1350
2016
Giuliani, G.Graham, I., Groat, L., Giuliani, G.Gems: bringing the world together,IGC 35th., Session Mineralogy 1 p. abstractTechnologyMineralogy
DS201709-1984
2017
Giuliani, G.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.
DS201811-2573
2015
Giuliani, G.Giuliani, G., Branquet, Y., Fallick, A.E., Groat, L.A., Marshall, D.Emerald deposits around the world, their similarities and differences.InColor, December pp. 56-69.Globalemeralds
DS202003-0340
2019
Giuliani, G.Giuliani, G., Groat, L.A.Geology of corundum and emerald gem deposits: a review.Gems & Gemology, Vol. 55, 4, pp. 464-511.Africa, Madagascar, Zambia, Asia, Sri Lanka, South America, Colombiaemerald

Abstract: The great challenge of geographic origin determination is to connect the properties and features of individual gems to the geology of their deposits. Similar geologic environments can produce gems with similar gemological properties, making it difficult to find unique identifiers. Over the last two decades, our knowledge of corundum and emerald deposit formation has improved significantly. The mineral deposits are classically separated into primary and secondary deposits. Primary corundum deposits are subdivided into two types based on their geological environment of formation: (1) magmatic and (2) metamorphic. Magmatic deposits include gem corundum in alkali basalts as in eastern Australia, and sapphire in lamprophyre and syenite as in Montana (United States) and Garba Tula (Kenya), respectively. Metamorphic deposits are divided into two subtypes (1) metamorphic deposits sensu stricto (in marble; mafic and ultramafic rocks, or M-UMR), and (2) metamorphic-metasomatic deposits characterized by high fluid-rock interaction and metasomatism (i.e., plumasite or desilicated pegmatites in M-UMR and marble, skarn deposits, and shear zonerelated deposits in different substrata, mainly corundum-bearing Mg-Cr-biotite schist). Examples of the first subtype include the ruby deposits in marble from the Mogok Stone Tract or those in M-UMR from Montepuez (Mozambique) and Aappaluttoq (Greenland). The second subtype concerns the sapphire from Kashmir hosted by plumasites in M-UMR. Secondary corundum deposits (i.e., present-day placers) result from the erosion of primary corundum deposits. Here, corundum is found in the following types of deposits: eluvial (derived by in situ weathering or weathering plus gravitational movement), diluvial (scree or talus), colluvial (deposited at the base of slopes by rainwash, sheetwash, slow continuous downslope creep, or a combination of these processes), and alluvial (deposited by rivers). Today, most sapphires are produced from gem placers related to alkali basalts, as in eastern Australia or southern Vietnam, while placers in metamorphic environments, such as in Sri Lanka (Ratnapura, Elahera) and Madagascar (Ilakaka), produce the highest-quality sapphires. The colluvial Montepuez deposit in Mozambique provides a huge and stable supply of clean and very high-quality rubies. Primary emerald deposits are subdivided into two types based on their geological environment of formation: (1) tectonic-magmatic-related (Type I) and (2) tectonic-metamorphic-related (Type II). Several subtypes are defined and especially Type IA, hosted in M-UMR, which accounts for about 70% of worldwide production (Brazil, Zambia, Russia, and others). It is characterized by the intrusion of pegmatites or quartz veins in M-UMR accompanied by huge hydrothermal fluid circulation and metasomatism with the formation of emerald-bearing desilicated pegmatite (plumasite) and biotite schist. Type IB in sedimentary rocks (China, Canada, Norway, Kazakhstan, and Australia) and Type IC in granitic rocks (Nigeria) are of minor importance. The subtype Type IIA of metamorphic deposits is related to hydrothermal fluid circulation at high temperature, in thrust fault and/or shear zones within M-UMR of volcano-sedimentary series, such as at the Santa Terezinha de Goiás deposit in Brazil. The subtype Type IIB is showcased by the Colombian emerald deposits located in the Lower Cretaceous black shales of the Eastern Cordillera Basin. These are related to the circulation of hydrothermal basinal fluids in black shales, at 300330°C, that dissolved evaporites in (1) thrust and tear faults for the deposits of the western emerald zone (Yacopi, Coscuez, Muzo, Peñas Blancas, Cunas, and La Pita mines) and (2) a regional evaporite level intercalated in the black shales or the deposits of the eastern emerald zone (Gachalá, Chivor, and Macanal mining districts). Secondary emerald deposits are unknown because emerald is too fragile to survive erosion and transport in rivers.
DS201212-0553
2012
Giullani, A.Phillips, D., Giullani, A., Jelsma, H., Joy, S.40Ar/39AR analyses of kelphite: a new approach for dating kimberlites and related rocks.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, South Africa, AngolaDeposit Dando Kwanza
DS2003-0256
2003
Giunchi, C.Cianetti, S., Giunchi, C., Spada, G.Mantle viscosity beneath the Hudson Bay: an inversion based on the MetropolisJournal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO! 10.1029/2001JB000585OntarioGeophysics - seismics
DS200412-0330
2003
Giunchi, C.Cianetti, S., Giunchi, C., Spada, G.Mantle viscosity beneath the Hudson Bay: an inversion based on the Metropolis algorithm.Journal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO! 10.1029/2001 JB000585Canada, OntarioGeophysics - seismics
DS202005-0744
2020
Giunta, T.Labidi, J., Barry, P.H., Bekaert, D.V., Broadley, M.W., Marty, B., Giunta, T., Warr, O., Sherwood Lollar, B., Fischer, T.P., Avice, G., Caracusi, A., Ballentine, C.J., Halldorsson, S.A., Stefansson, A., Kurz, M.D., Kohl, I.E., Young, E.D.Hydrothermal 15N15N abundances constrain the origins of mantle nitrogen.Nature, Vol. 580, 7803 pp. 367-371. Mantlenitrogen

Abstract: Nitrogen is the main constituent of the Earth’s atmosphere, but its provenance in the Earth’s mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth’s accretion versus that subducted from the Earth’s surface is unclear1,2,3,4,5,6. Here we show that the mantle may have retained remnants of such primordial nitrogen. We use the rare 15N15N isotopologue of N2 as a new tracer of air contamination in volcanic gas effusions. By constraining air contamination in gases from Iceland, Eifel (Germany) and Yellowstone (USA), we derive estimates of mantle ?15N (the fractional difference in 15N/14N from air), N2/36Ar and N2/3He. Our results show that negative ?15N values observed in gases, previously regarded as indicating a mantle origin for nitrogen7,8,9,10, in fact represent dominantly air-derived N2 that experienced 15N/14N fractionation in hydrothermal systems. Using two-component mixing models to correct for this effect, the 15N15N data allow extrapolations that characterize mantle endmember ?15N, N2/36Ar and N2/3He values. We show that the Eifel region has slightly increased ?15N and N2/36Ar values relative to estimates for the convective mantle provided by mid-ocean-ridge basalts11, consistent with subducted nitrogen being added to the mantle source. In contrast, we find that whereas the Yellowstone plume has ?15N values substantially greater than that of the convective mantle, resembling surface components12,13,14,15, its N2/36Ar and N2/3He ratios are indistinguishable from those of the convective mantle. This observation raises the possibility that the plume hosts a primordial component. We provide a test of the subduction hypothesis with a two-box model, describing the evolution of mantle and surface nitrogen through geological time. We show that the effect of subduction on the deep nitrogen cycle may be less important than has been suggested by previous investigations. We propose instead that high mid-ocean-ridge basalt and plume ?15N values may both be dominantly primordial features.
DS201806-1222
2018
Giuntoli, F.Engi, M., Giuntoli, F., Lanari, P., Burn, M., Kunz, B., Bouvier, A.S.Pervasive eclogization due to brittle deformation and rehydration of subducted basement: effects on continental recycling?Geochemistry, Geophysics, Geosystems, Vol. 19, 3, pp. 865-881.Mantlesubduction

Abstract: The buoyancy of continental crust opposes its subduction to mantle depths, except where mineral reactions substantially increase rock density. Sluggish kinetics limit such densification, especially in dry rocks, unless deformation and hydrous fluids intervene. Here we document how hydrous fluids in the subduction channel invaded lower crustal granulites at 50-60 km depth through a dense network of probably seismically induced fractures. We combine analyses of textures and mineral composition with thermodynamic modeling to reconstruct repeated stages of interaction, with pulses of high-pressure (HP) fluid at 650-6708C, rehydrating the initially dry rocks to micaschists. SIMS oxygen isotopic data of quartz indicate fluids of crustal composition. HP growth rims in allanite and zircon show uniform U-Th-Pb ages of 65 Ma and indicate that hydration occurred during subduction, at eclogite facies conditions. Based on this case study in the Sesia Zone (Western Italian Alps), we conclude that continental crust, and in particular deep basement fragments, during subduction can behave as substantial fluid sinks, not sources. Density modeling indicates a bifurcation in continental recycling: Chiefly mafic crust, once it is eclogitized to >60%, are prone to end up in a subduction graveyard, such as is tomographically evident beneath the Alps at 550 km depth. By contrast, dominantly felsic HP fragments and mafic granulites remain positively buoyant and tend be incorporated into an orogen and be exhumed with it. Felsic and intermediate lithotypes remain positively buoyant even where deformation and fluid percolation allowed them to equilibrate at HP.
DS201212-0451
2012
Giurco, D.May, D., Cordell, D., Giurco, D.Peak minerals: theoretical foundations and practical application.Natural Resources Research, Vol. 21, 1, pp. 43-60.GlobalEconomics - (oil related)
DS2001-1190
2001
Givers, R.Van Wijk, J.W., Givers, R., Furlong, K.P.Three dimensional thermal modeling of the California upper mantle: a slab window vs. stalled slab.Earth and Planetary Science Letters, Vol. 186, No. 2, March 30, pp. 175-86.CaliforniaSubduction, Geothermometry
DS1992-0578
1992
Gjata, K.Gjata, K., Kornprobst, J., Kodra, A., et al.Hot subduction close to a ridge? Example of garnet pyroxenite inclusions In the serpentine breccia (in French)Soc. Geol. de France, Bulletin. Huitieme series, (in French), Vol. 163, No. 4, pp. 469-476.AlbaniaXenoliths, Mantle
DS2000-0341
2000
Glacken, I.M.Glacken, I.M., Snowden, D.V.Mineral resource estimationMin. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 189-98.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS1992-1734
1992
Gladkikh, V.C.Zhabin, A.G., Gladkikh, V.C.The equilibrium structures of mineral aggregates in deep seated lherzolitenodulesDoklady Academy of Science USSR, Earth Science Section, Vol. 313, No. 106, June pp. 204-207RussiaLherzolite
DS1985-0236
1985
Gladkikh, V.S.Gladkikh, V.S., Lyapunov, S.M., Konova, M.I., Yermolayev, V.V.Geochemistry and Petrology of Volcanic Rocks in Maymecha Kotuy ProvinceGeochemistry International, Vol. 22, No. 1, pp. 157-167RussiaBlank
DS1989-0516
1989
Gladkikh, V.S.Gladkikh, V.S., Solovev, V.A.Niobium and zirconium in alkaline olivine basalts and alkaline basaltoids of the Baikal-Mongolian regions as criteria for estimating their distrib. In mantle sourceSoviet Geology and Geophysics, Vol. 30, No. 2, pp. 62-68RussiaAlkaline basaltoids, Rare earths
DS1991-0579
1991
Gladkikh, V.S.Gladkikh, V.S.Geochemistry of volcanic melilite rocks of Maymecha-Kotuy Province. (Russian)Geochemistry International (Geokhimiya), (Russian), No. 4, April pp. 583-593RussiaGeochemistry, Melilite
DS1991-0580
1991
Gladkikh, V.S.Gladkikh, V.S.Geochemistry of melilitic volcanic rocks in the Maymecha-Kotoy ProvinceGeochemistry International, Vol. 28, No. 11, pp. 119-128RussiaGeochemistry, Melilitite
DS1994-0625
1994
Gladkikh, V.S.Gladkikh, V.S.Geochemistry of the volcanic rocks from the Maimecha Kotui province, Siberian craton.Petrology, Vol. 2, No. 5, pp. 494-RussiaGeochemistry
DS2001-0265
2001
GladkochubDonskaya, T.V., Salnikova, Sklyarov, GladkochubEarly Proterozoic Post collision magmatism at the southern flank of the Siberian Craton: geochronological...Doklady, Vol.383, No. 1-2, Feb-Mar. pp. 125-8.Russia, SiberiaGeodynamic - magmatism, Geochronology
DS200512-0864
2005
Gladkochub, D.Poller, U., Gladkochub, D., Donskaya, T., Mazukabzov, A., Sklyarov, E., Todt, W.Multistage magmatic and metamorphic evolution in the southern Siberian craton: Archean and paleoproterozoic zircon ages revealed by SHRIMP and TIMS.Precambrian Research, Vol. 136, 3-4, pp. 353-368.Russia, SiberiaGeochronology
DS200612-0467
2006
Gladkochub, D.Gladkochub, D., Pisarevsky, S., Donskaya, L., Mazukabzov, A., Stanevich, A., Sklyarov, E.Siberian Craton and its evolution in terms of Rodinia hypothesis.Episodes, Vol. 29, 3, pp. 169-174.Russia, SiberiaCraton, genesis
DS2001-0385
2001
Gladkochub, D.P.Gladkochub, D.P., Sklyarov, Donskaya, MazukabzovPetrology of gabbro dolerites from Neoproterozoic dike swarms in the Sharyzhalgai block - problem breakup...Petrology, Vol. 9, No. 6, pp. 560-75.RussiaTectonics - Rodinia supercontinent, Dike swarms
DS2001-0386
2001
Gladkochub, D.P.Gladkochub, D.P., Sklyarov, Donskaya, Mazukabzov, et al.Petrology of gabbro dolerites from Neoproterozoic dike swarms in Sharyzhalgai Block with reference to problemPetrology, Vol.9, 6, pp. 560-75.Russia, SiberiaCraton - breakup of the Rodinia supercontinent, Magma - melt
DS2001-0387
2001
Gladkochub, D.P.Gladkochub, D.P., Sklyarov, E.V., Menshagin, MazukabzovGeochemistry of ancient ophiolites of the Sharyzhalgai upliftGeochemistry International, Vol. 39, No. 10, pp. 947-58.RussiaOphiolite - geochemistry
DS2002-0578
2002
Gladkochub, D.P.Gladkochub, D.P., Donskaya, T.V., Mazukabzov, A.M., Sklyarov, E.V.The Urik Iya graben of the Sayan In lier of the Siberian Craton: new geochronologicalDoklady Earth Sciences, Vol. 386, 7, Sept-Oct.pp. 737-41.Russia, SiberiaGeochronology, Geodynamics, tectonics - not specific to diamonds
DS2002-1505
2002
Gladkochub, D.P.Sklyarov, E.V., Gladkochub, D.P., Mazukabzov, A.M., Donskaya, T.V.Geological complexes in the margin of the Siberian Craton as indicators of the evolutionRussian Journal of Earth Science, Vol. 4, 3, JuneRussiaMagmatism, Gondwana
DS2003-1290
2003
Gladkochub, D.P.Sklyarov, E.V., Gladkochub, D.P., Mazukabzov, A.M., Menshagin, Y.V.Neoproterozoic mafic dike swarms of the Sharyzhalgai metamorphic massif, southernPrecambrian Research, Vol. 122, 1-4, pp.359-76.Russia, SiberiaDyke swarms, Magmatism
DS200412-1484
2004
Gladkochub, D.P.Ota, T., Gladkochub, D.P., Skylarov, E.V., Mazukabzov, A.M., Watanabe, T.P T history of garnet websterites in the Sharyzhalgai complex, southwestern margin Siberian Craton: evidence from PaleproterozoiPrecambrian Research, Vol. 132, 4, pp. 327-348.Russia, SiberiaMetamorphism
DS200412-1847
2003
Gladkochub, D.P.Sklyarov, E.V., Gladkochub, D.P., Mazukabzov, A.M., Menshagin, Y.V., Watanabe, T., Pisarevsky, S.A.Neoproterozoic mafic dike swarms of the Sharyzhalgai metamorphic massif, southern Siberian craton.Precambrian Research, Vol. 122, 1-4, pp.359-76.Russia, SiberiaDyke swarms Magmatism
DS200512-0865
2005
Gladkochub, D.P.Poller, U., Gladkochub, D.P., Donskaya, T.V., Mazukabzov, A.M., Sklyarov, E.V., Todt, W.Timing of Early Proterozoic magmatism along the southern margin of the Siberian Craton ( Kitoy area).Geological Society of America Special Paper, No. 389, pp. 215-226.RussiaMagmatism ( not specific to diamonds)
DS200612-0468
2006
Gladkochub, D.P.Gladkochub, D.P., Wingate, M.T.D., Pisarevsky, S.A., Donskaya, T.V., Mazukababzov, Ponomarchuk, StanevichMafic intrusions in southwestern Siberia and implications for a Neoproterozoic connection with Laurentia.Precambrian Research, Vol. 147, 3-4, July 5, pp. 260-278.Russia, CanadaMagmatism
DS200612-0469
2006
Gladkochub, D.P.Gladkochub, D.P., Wingate, M.T.D., Pisarevsky, S.A., Donskaya, T.V., Mazukabzov, Ponomarchuk, StanevichMafic intrusions in southwestern Siberia and implications for a Neoproterozoic connection with Laurentia.Precambrian Research, In press, availableRussia, SiberiaGeochronology, Biryusa, magmatism
DS200712-0363
2007
Gladkochub, D.P.Gladkochub, D.P., Donskaya, T.V., Mazukabzov, A.M., Stanevich, A.M., Sklyarov, E.V., Ponomarchuk, V.A.Signature of Precambrian extension events in the southern Siberian Craton.Russian Geology and Geophysics, Vol. 48, pp. 17-31.RussiaDike swarm, rifting, Rodinia
DS200712-0847
2006
Gladkochub, D.P.Pisarevsky, S.A., Gladkochub, D.P., Donskaya, T.A., De Waeel, B., Mazukabzov, A.M.Paleomagnetism and geochronology of mafic dykes in south Siberia, Russia: the first precisely dated Permian paleomagnetic pole from the Siberian Craton.Geophysical Journal International, Vol. 167, 2, pp. 649-658.RussiaGeochronology
DS200812-0413
2008
Gladkochub, D.P.Gladkochub, D.P., Sklyarov, E.V., Donskaya, T.V., Stanevich, A.M., Mazukabzov, A.M.A period of global uncertainty ( Blank spot) in the Precambrian history of the southern Siberian Craton and the problem of the transproterozoic supercontinent.Doklady Earth Sciences, Vol. 421, 1, pp. 774-778.Russia, SiberiaTectonics
DS200912-0182
2009
Gladkochub, D.P.Donskaya, T.V., Gladkochub, D.P., Pisarevsky, S.A., Poller, U., Mazukabov, A.M., Bayanova, T.B.Discovery of Archean crust within the Akitkan orogenic belt of the Siberian craton: new insight into its architecture and history.Precambrian Research, Vol. 170, 1-2, pp. 61-72.Russia, SiberiaTectonics
DS201012-0236
2010
Gladkochub, D.P.Gladkochub, D.P., Pisarevsky, S.A., Ernst, R., Donskaya, T.V., Soderlund, U., Mazukabzov, A.M., Hanes, J.Large igneous province of about 1750 Ma in the Siberian Craton.Doklady Earth Sciences, Vol. 430, 2, pp. 163-167.RussiaMagmatism
DS201312-0315
2013
Gladkochub, D.P.Gladkochub, D.P., Kostrovitskii, S.I., Donskaya, T.V., De Waele, B., Mazukabzov, A.M.Age of zircons from diamond bearing lamproites of the East Sayan as an indicator of known and unkonwn endogenous events in the south Siberian craton.Doklady Earth Sciences, Vol. 450, 2, June pp. 597-601.Russia, SayanLamproite
DS201607-1290
2016
Gladkochub, D.P.Cawood, P.A., Strachan, R.A., Pisarevsky, S.A., Gladkochub, D.P., Murphy, J.B.Linking collisional and accretionary orogens during Rodinia assembly and breakup: implications for models of supercontinent cycles.Earth and Planetary Science Letters, Vol. 449, pp. 118-126.Gondwana, RodiniaSubduction

Abstract: Periodic assembly and dispersal of continental fragments has been a characteristic of the solid Earth for much of its history. Geodynamic drivers of this cyclic activity are inferred to be either top-down processes related to near surface lithospheric stresses at plate boundaries or bottom-up processes related to mantle convection and, in particular, mantle plumes, or some combination of the two. Analysis of the geological history of Rodinian crustal blocks suggests that internal rifting and breakup of the supercontinent were linked to the initiation of subduction and development of accretionary orogens around its periphery. Thus, breakup was a top-down instigated process. The locus of convergence was initially around north-eastern and northern Laurentia in the early Neoproterozoic before extending to outboard of Amazonia and Africa, including Avalonia-Cadomia, and arcs outboard of Siberia and eastern to northern Baltica in the mid-Neoproterozoic (?760 Ma). The duration of subduction around the periphery of Rodinia coincides with the interval of lithospheric extension within the supercontinent, including the opening of the proto-Pacific at ca. 760 Ma and the commencement of rifting in east Laurentia. Final development of passive margin successions around Laurentia, Baltica and Siberia was not completed until the late Neoproterozoic to early Paleozoic (ca. 570-530 Ma), which corresponds with the termination of convergent plate interactions that gave rise to Gondwana and the consequent relocation of subduction zones to the periphery of this supercontinent. The temporal link between external subduction and internal extension suggests that breakup was initiated by a top-down process driven by accretionary tectonics along the periphery of the supercontinent. Plume-related magmatism may be present at specific times and in specific places during breakup but is not the prime driving force. Comparison of the Rodinia record of continental assembly and dispersal with that for Nuna, Gondwana and Pangea suggests grouping into two supercycles in which Nuna and Gondwana underwent only partial or no break-up phase prior to their incorporation into Rodinia and Pangea respectively. It was only after this final phase of assembly that the supercontinents then underwent full dispersal.
DS201607-1295
2016
Gladkochub, D.P.Ernst, R.E., Hamilton, M.A., Soderlund, U., Hanes, J.A., Gladkochub, D.P., Okrugin, A.V., Kolotilina, T., Mekhonoshin, A.S., Bleeker, W., LeCheminant, A.N., Buchan, K.L., Chamberlain, K.R., Didenko, A.N.Long lived connection between southern Siberia and northern Laurentia in the Proterozoic.Nature Geoscience, Vol. 9, 6, pp. 464-469.Canada, RussiaProterozoic

Abstract: Precambrian supercontinents Nuna-Columbia (1.7 to 1.3 billion years ago) and Rodinia (1.1 to 0.7 billion years ago) have been proposed. However, the arrangements of crustal blocks within these supercontinents are poorly known. Huge, dominantly basaltic magmatic outpourings and intrusions, covering up to millions of square kilometres, termed Large Igneous Provinces, typically accompany (super) continent breakup, or attempted breakup and offer an important tool for reconstructing supercontinents. Here we focus on the Large Igneous Province record for Siberia and Laurentia, whose relative position in Nuna-Columbia and Rodinia reconstructions is highly controversial. We present precise geochronology—nine U -Pb and six Ar -Ar ages—on dolerite dykes and sills, along with existing dates from the literature, that constrain the timing of emplacement of Large Igneous Province magmatism in southern Siberia and northern Laurentia between 1,900 and 720 million years ago. We identify four robust age matches between the continents 1,870, 1,750, 1,350 and 720 million years ago, as well as several additional approximate age correlations that indicate southern Siberia and northern Laurentia were probably near neighbours for this 1.2-billion-year interval. Our reconstructions provide a framework for evaluating the shared geological, tectonic and metallogenic histories of these continental blocks.
DS201712-2686
2017
Gladkochub, D.P.Gladkochub, D.P., Donskaya, T.V., Sklyarov, E.V., Kotov, A.B., Vladykin, N.V., Pisarevsky, S.A., Larin, A.M., Salnikova, E.B., Saveleva, V.B., Sharygin, V.V., Starikova, A.E., Tolmacheva, E.V., Velikoslavinsky, S.D., Mazukabzov, A.M., Bazarova, E.P., KovaThe unique Katugin rare metal deposit ( southern Siberia): constraints on age and genesis.Ore Geology Reviews, in press available, 18p.Russia, Siberiadeposit - Katugin

Abstract: We report new geological, mineralogical, geochemical and geochronological data about the Katugin Ta-Nb-Y-Zr (REE) deposit, which is located in the Kalar Ridge of Eastern Siberia (the southern part of the Siberian Craton). All these data support a magmatic origin of the Katugin rare-metal deposit rather than the previously proposed metasomatic fault-related origin. Our research has proved the genetic relation between ores of the Katugin deposit and granites of the Katugin complex. We have studied granites of the eastern segment of the Eastern Katugin massif, including arfvedsonite, aegirine-arfvedsonite and aegirine granites. These granites belong to the peralkaline type. They are characterized by high alkali content (up to 11.8?wt% Na2O?+?K2O), extremely high iron content (FeO?/(FeO??+?MgO)?=?0.96-1.00), very high content of most incompatible elements - Rb, Y, Zr, Hf, Ta, Nb, Th, U, REEs (except for Eu) and F, and low concentrations of CaO, MgO, P2O5, Ba, and Sr. They demonstrate negative and CHUR-close ?Nd(t) values of 0.0…?1.9. We suggest that basaltic magmas of OIB type (possibly with some the crustal contamination) represent a dominant part of the granitic source. Moreover, the fluorine-enriched fluid phases could provide an additional source of the fluorine. We conclude that most of the mineralization of the Katugin ore deposit occurred during the magmatic stage of the alkaline granitic source melt. The results of detailed mineralogical studies suggest three major types of ores in the Katugin deposit: Zr mineralization, Ta-Nb-REE mineralization and aluminum fluoride mineralization. Most of the ore minerals crystallized from the silicate melt during the magmatic stage. The accessory cryolites in granites crystallized from the magmatic silicate melt enriched in fluorine. However, cryolites in large veins and lens-like bodies crystallized in the latest stage from the fluorine enriched melt. The zircons from the ores in the aegirine-arfvedsonite granite have been dated at 2055?±?7?Ma. This age is close to the previously published 2066?±?6?Ma zircon age of the aegirine-arfvedsonite granites, suggesting that the formation of the Katugin rare-metal deposit is genetically related to the formation of peralkaline granites. We conclude that Katugin rare-metal granites are anorogenic. They can be related to a Paleoproterozoic (?2.05?Ga) mantle plume. As there is no evidence of the 2.05?Ga mantle plume in other areas of southern Siberia, we suggest that the Katugin mineralization occurred on the distant allochtonous terrane, which has been accreted to Siberian Craton later.
DS201812-2843
2018
Gladkochub, D.P.Lunina, O., Glaskov, A.S., Gladkochub, D.P., Joao, F., Karpenko, M.A., Felix, J.T., Koshkarev, D.A., Sklyarov, E.The evolution of the crustal stress state of the Catoca kimberlite pipe area, northeastern Angola. IN RUSGeodynamics and Tectonphysics in RUS, Vol. 9, 3, pp. 827-854. only 1 p. english abstractAfrica, Angoladeposit - Catoca

Abstract: This paper presents the first results of the geostructural and tectonophysical studies of the crustal stress state in the Catoca kimberlite pipe area at the southwestern flank of the Kasai Shield in the northeasternAngola. In the evolution of the crustal stress state, six main stages are distinguished by analyzing the displacements of markers, fold hinges, long axes of boudins, granite dikes of various intrusion phases and kimberlites, as well as fractures with striations. For each of these stages, a dominating horizontal tectonic stress and its orientation is identified. During stage 1 (NW extension and shearing) and at the beginning of stage 2 (NW compression), structures formed in the host rocks in brittle-plastic conditions. The replacement of plastic deformation by faulting could occur about 530-510 Ma ago, when the continental crust ofAfricahad completely formed. Stage 3 (radial, mainly NW extension) and stage 4 (shearing, NW extension, and NE compression) were the most important for kimberlite occurrence: in the Early Cretaceous, radial extension was replaced by shearing. Both stages are related to opening of the central segment of theSouth Atlantic. The main kimberlite magmas occurred during the break-up of the Angola-Brazilian segment of Gondwana. In the course of all the four stages, stress was mainly released by the NE- and E-NE-striking faults and, to a lesser extent, by the NW-striking and latitudinal faults. The initial stage of kimberlite magmatism is associated with the NE- and E-NE-striking faults due to the presence of the Precambrian zones of flow and schistosity, which facilitated the NW-trending subhorizontal extension. Stage 5 (NE compression) began in the second half of the Cretaceous and possibly lasted until the end of the Paleogene, and compression occurred mainly along the NW-striking faults. Regionally, it corresponds to two stages of inversion movements in the southern regions of Africa, during which theAngoladome-shaped uplift emerged and the shoulders of the East African rifts began to take shape. Stage 6 (horizontal extension, mainly in the N-NE direction) is related to the processes that took place in the southern segment of theTanganyikarift and the eastern coast of theAtlantic. Based on the results of our studies, it became for the first time possible to get an idea of the main stages in the evolution of the studied region. Further geostructural measurements and dating of the host rocks will provide for a more precise definition of the proposed stages.
DS201902-0294
2018
Gladkochub, D.P.Malyeshev, S.V., Pasenko, A.M., Ivanov, A.V., Gladkochub, D.P., Savatenkov, V.M., Meffre, S., Abersteiner, A., Kamenetsky, V.S., Shcherbakov, V.D.Geodynamic significance of the Mesoproterozoic magmatism of the Udzha paleo-rift ( Northern Siberian craton) based in U-Pb geochronology and paleomagnetic data.Minerals ( mdpi.com), Vol. 8, 12, 11p. PdfRussia, Siberiacraton

Abstract: The emplacement age of the Great Udzha Dyke (northern Siberian Craton) was determined by the U-Pb dating of apatite using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). This produced an age of 1386 ± 30 Ma. This dyke along with two other adjacent intrusions, which cross-cut the sedimentary units of the Udzha paleo-rift, were subjected to paleomagnetic investigation. The paleomagnetic poles for the Udzha paleo-rift intrusions are consistent with previous results published for the Chieress dyke in the Anabar shield of the Siberian Craton (1384 ± 2 Ma). Our results suggest that there was a period of intense volcanism in the northern Siberian Craton, as well as allow us to reconstruct the apparent migration of the Siberian Craton during the Mesoproterozoic.
DS202007-1143
2020
Gladkochub, D.P.Gladkochub, D.P., Donskaya, T.V.Geochemical composition of dolerites as an indicator of the distance of a dike swarm from the mantle plume center ( case study of Proterozoic dike swarms, Siberian craton).Doklady Earth Sciences, Vol. 491, pp. 243-246.Russia, Siberiadyke

Abstract: Based on investigation of Proterozoic mafic dike swarms of the Siberian Craton, we inferred how the geochemical and isotopic characteristics of dike swarms of dolerites of Large Igneous Provinces depend on their distance from the mantle plume head. It has been found that the dolerite parent melts near the mantle plume head correspond to OIB compositions. At significant distances from the plume, the initial melts of dolerites are generated in the subcontinental lithospheric mantle, which provides a wide range of their compositions differing from typical OIB and do not indicate directly the genetic relationship of these mafic rocks with the mantle plume.
DS202102-0194
2021
Gladkochub, D.P.Gladkochub, D.P., Donskaya, T.V., Pisarevesky, S.A., Salnikova E.B., Mazukabzov, A.M., Kotov, A.B., Motova, Z.I., Stepanova, A.V., Kovach, V.P.Evidence of the latest Paleoproterozoic ( ~1615 Ma) mafic magmatism the southern Siberia: extensional environments in Nuna subcontinent.Precambrian Research, Vol. 354, doi.org/10.1016 /j.precamres. 2020.10049 14p. PdfRussiaCraton - Siberian
DS202202-0201
2022
Gladkochub, D.P.Kostrivitsky, S.I., Yakolev, D.A., Sharygin, I.S., Gladkochub, D.P., Donskaya, T.V., Tretiakova, I.G., Dymshits, A.M.Diamondiferous lamproites of Ingashi field, Siberian craton.Geological Society of London Special Publication 513, pp. 45-70.Russialamproites

Abstract: Ingashi lamproite dykes are the only known primary sources of diamond in the Irkutsk district (Russia) and the only non-kimberlitic one in the Siberian craton. The Ingashi lamproite field is situated in the Urik-Iya graben within the Prisayan uplift of the Siberian craton. The phlogopite-olivine lamproites contain olivine, talc, phlogopite, serpentine, chlorite, olivine, garnet, chromite, orthopyroxene, clinopyroxene as well as Sr-F-apatite, monazite, zircon, armolcolite, priderite, potassium Mg-arfvedsonite, Mn-ilmenite, Nb-rutile and diamond. The only ultramafic lamprophyre dyke is composed mainly of serpentinized olivine and phlogopite in the talc-carbonate groundmass and is similar to Ingashi lamproites accessory assemblage with the same major element compositions. Trace element and Sr-Nd isotopic relationships of the Ingashi lamproites are similar to classic lamproites. Different dating methods have provided the ages of lamproites: 1481 Ma (Ar-Ar phlogopite), 1268 Ma (Rb-Sr whole rock) and 300 Ma (U-Pb zircon). Ingashi lamproite ages are controversial and require additional study. The calculated pressure of 3.5 GPamax for clinopyroxenes indicates that lamproite magma originated deeper than 100 km. A Cr-in-garnet barometer shows a 3.7-4.3 GPamin and derivation of Ingashi lamproites deeper than 120 km in depth. Based on the range of typical cratonic geotherms and the presence of diamonds, the Ingashi lamproite magma originated at a depth greater than 155 km.
DS200412-1246
2004
Gladkov, A.S.Matrosov, V.A., Bornyakov, S.A., Gladkov, A.S.A new approach to optimization of prognostic prospecting for Diamondiferous kimberlites.Doklady Earth Sciences, Vol. 395, 2, pp. 192-195.RussiaDiamond prospecting technique
DS200512-0344
2005
Gladkov, A.S.Gladkov, A.S., Zinchuk, N.N, Bornyakov, S.A., Sherman, S.I., Manakov, A.V., Matrosov, V.A., Garat, DzyubaNew dat a on the internal structure and formation mechanism of kimberlite hosting fault zones in the Malaya Botuoba region, Yakutian Diamondiferous provinceDoklady Earth Sciences, Vol. 402, 4, pp. 520-23.Russia, YakutiaTectonics, structure, Malaya Botuoba
DS200812-1083
2008
Gladkov, A.S.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
DS200912-0401
2009
Gladkov, A.S.Konstantinov, K.M., Gladkov, A.S.Petromagnetic hterogeneities in sintering zones of Permian-Triassic traps of Komsomolsk pipe deposit ( Yakutsk diamond province).Doklady Earth Sciences, Vol. 427, 5, pp. 880-886.Russia, YakutiaDeposit - Komsomolsk
DS201012-0237
2010
Gladkov, A.S.Gladkov, A.S., Makovchuk, I.V., Lunina, O.V., Bornyakov, S.A., Potekhina, I.A.The Yubieinaya kimberlite pipe site, Russia: 3 D model of the fault block structure.Geology of Ore Deposits, Vol. 52, 3, pp. 234-251.RussiaStructure
DS1993-0362
1993
Gladkov, I.N.Dobretsov, N.L., Kirdyashkin, A.G., Gladkov, I.N.Problems of deep seated geodynamics and modelling of mantle plumesRussian Geology and Geophysics, Vol. 34, No. 12, pp. 3-20.MantleGeodynamics, Mantle plumes
DS1996-0745
1996
Gladkov, I.N.Kirdyashkin, A.G., Gladkov, I.N.Mantle plumes and hot spotsDoklady Academy of Sciences, Vol. 343A No. 6, June pp. 26-30.MantlePlumes, Hotspots
DS200512-0539
2005
Gladkov, I.N.Kirdyashkin, A.A., Dobretsov, N.L., Kirdyashkin, A.G., Gladkov, I.N., Surkov, N.V.Hydrodynamic processes associated with plume rise and conditions for eruption conduit formation.Russian Geology and Geophysics, Vol. 46, 9, pp. 869-885.MantleGeodynamics
DS200612-0337
2006
Gladkov, I.N.Dobretsov, N.L., Kirdyashkin, A.A., Kirdyashkin, A.G., Gladkov, I.N., Surkov, N.V.Parameters of hotspots and thermochemical plumes during their ascent and eruption.Petrology, Vol. 14, 5, pp. 477-491.MantleGeothermometry - hot spots
DS1985-0694
1985
Gladney, E.S.Vaniman, D., Laughlin, A.W., Gladney, E.S.Navajo Minettes in the Cerros de la Mujeres, New MexicoEarth Plan. Sci. Letters, Vol. 74, PP. 69-80.United States, Colorado Plateau, New MexicoMicroprobe Analyses, Geochemistry, Age Dating, Geochronology
DS1997-0419
1997
Gladwin, D.Gladwin, D., Konda, B., Lauer, Camilucci, D.A comparative analysis of income based taxes on miningThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 90, No. 1009, April pp. 33-35CanadaEconomics, Tax - mining
DS1980-0165
1980
Glahn, P.R.Hausel, W.D., Glahn, P.R., Woodzick, T.L.Exploration for Diamond Bearing Kimberlite in Colorado and Wyoming- an update.American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) REPRINT., No. 80-310, 4P.United States, Colorado, Wyoming, State Line, Rocky MountainsBlank
DS1981-0208
1981
Glahn, P.R.Hausel, W.D., Glahn, P.R., Woodzick, T.L.Geological and Geophysical Investigations of Kimberlite in The Laramie Range of Southeastern Wyoming.Wyoming Geological Survey Prelim. Report, No. 18, 13P.United States, Wyoming, State Line, Rocky MountainsKimberlite, Geophysics, Geochemistry, Geology, Schaffer
DS1985-0099
1985
Glaisher, R.W.Bursill, L.A., Glaisher, R.W.Aggregation and dissolution of small and extended defect structures in type IA diamondAmerican Mineralogist, Vol. 70, No. 5-6, pp. 608-618GlobalDiamond Morphology
DS1985-0100
1985
Glaisher, R.W.Bursill, L.A., Glaisher, R.W.Aggregation and Dissolution of Small and Extended Defect Structures in Type 1a Diamond.American Mineralogist., Vol. 70, No. 5/6, PP. 608-618.GlobalNitrogen, Diamond Morphology, Diagrams
DS1990-0577
1990
Glanville, R.Glanville, R.Evaluation of mineral exploration propertiesNorthwest Mining Convention, Held Spokane, Dec. 6, 1990, 21pGlobalEconomics, Reserves
DS1993-0549
1993
Glanzman, R.K.Glanzman, R.K., Closs, L.G.Quality assurance and control guidelines for exploration and environmental geochemistry investigationsExplore, No. 78, January pp. 1, 6GlobalGeochemistry, Control guidelines
DS201705-0831
2017
Glas, M.Glas, M.Diamond Studies.lithographie.org, No. 19, pp. 36-39.TechnologyBook - review
DS201511-1843
2015
Glasauer, S.Huang, J-H., Huang, F., Evans, L., Glasauer, S.Vanadium: global (bio)geochemistry.Chemical Geology, Vol. 417, pp. 68-89.MantleMineralogy

Abstract: Redox-sensitive transition group elements are involved in almost all fundamental geochemical processes. Of these elements, vanadium (V) contributes a particularly powerful tool to decipher the Earth's history and its link to extraterrestrial bodies. A comprehensive view of V includes the formation and interaction between the Earth's interior layers, the evolution of the Earth's surface to a habitable zone, biogeochemical cycling, and anthropogenic impacts on the environment. Tracing the geochemical behavior of V through the Earth's compartments reveals critical connections between almost all disciplines of Earth sciences. Vanadium has a history of application as a redox tracer to address the early accretion history of the Earth, to identify connections between the mantle and crust by subduction and melting, and to interpret past surface environments. The geochemical cycling of V from the deep Earth to the surface occurs through magmatism, weathering and digenesis, reflecting variations of fO2 and V species in different Earth compartments. Minerals form a link between deep Earth reservoirs of vanadium and surface environments, and the study of V in minerals has increased the understanding of V cycling. Finally, the exploitation of V has been increasing since the Industrial Revolution, and significant amounts of V have been released as a consequence into natural systems. Environmental concerns are promoting new areas of research to focus on V cycling between water, air, soil and sediment compartments. An increased understanding of V in all compartments, and knowledge of the processes that connect the compartments, is vital to tracing the fate of this intriguing element in natural systems.
DS1990-1504
1990
Glasbeek, M.Vanoort, E., Stroomer, P., Glasbeek, M.Low-field optically detected magnetic -resonance of a coupled triplet-doublet defect pair in diamondPhys. Rev. B., Vol. 42, No. 13, Nov. 1, pp. 8605-8608GlobalDiamond morphology, Experimental petrology
DS1996-0534
1996
Glasby, G.P.Glasby, G.P.The relation between ore deposit formations and subduction: mass balanceconsiderationsThe Island Arc, Vol. 5, No. 4, Dec. pp. 396-406JapanDeposit - Kuroko
DS200712-0714
2006
Glascock, M.Mendez, A.E., Prelas, M.A., Glascock, M., Ghosh, T.K.A novel method for the diffusion of boron in 60-80 micron size natural diamond Type II/A powder.Journal of Materials and Research, No. 929, pp. 155-160 Ingenta 1-64796903TechnologyType II diamonds
DS1990-0998
1990
Glascock, M.D.McCall, G.W., Nabelek, P.I., Bauer, R.L., Glascock, M.D.Petrogenesis of Archean lamprophyres in the southern Vermilion graniticcomplex, northeastern Minnesota, with implications for the nature of their mantle sourceContributions to Mineralogy and Petrology, Vol. 104, No. 4, pp. 439-452MinnesotaGranite -Vermilion complex, Lamprophyres
DS1990-1255
1990
Glascock, M.D.Roggensack, K., Barreiro, B., Stoiber, R.E., Glascock, M.D.Mantle heterogeneity in northwest New England as shown by MesozoiclamprophyresGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A255GlobalCamptonite, Mantle
DS1998-0437
1998
Glaser, S.M.Foley, S.F., Glaser, S.M., Andronikov, A.V.Non-cratonic garnet peridotites from rifted continental settings in ( Baikal Rift) and East Antarctica7th International Kimberlite Conference Abstract, pp. 217-219.Russia, Baikal, AntarcticaGarnet peridotites
DS201812-2843
2018
Glaskov, A.S.Lunina, O., Glaskov, A.S., Gladkochub, D.P., Joao, F., Karpenko, M.A., Felix, J.T., Koshkarev, D.A., Sklyarov, E.The evolution of the crustal stress state of the Catoca kimberlite pipe area, northeastern Angola. IN RUSGeodynamics and Tectonphysics in RUS, Vol. 9, 3, pp. 827-854. only 1 p. english abstractAfrica, Angoladeposit - Catoca

Abstract: This paper presents the first results of the geostructural and tectonophysical studies of the crustal stress state in the Catoca kimberlite pipe area at the southwestern flank of the Kasai Shield in the northeasternAngola. In the evolution of the crustal stress state, six main stages are distinguished by analyzing the displacements of markers, fold hinges, long axes of boudins, granite dikes of various intrusion phases and kimberlites, as well as fractures with striations. For each of these stages, a dominating horizontal tectonic stress and its orientation is identified. During stage 1 (NW extension and shearing) and at the beginning of stage 2 (NW compression), structures formed in the host rocks in brittle-plastic conditions. The replacement of plastic deformation by faulting could occur about 530-510 Ma ago, when the continental crust ofAfricahad completely formed. Stage 3 (radial, mainly NW extension) and stage 4 (shearing, NW extension, and NE compression) were the most important for kimberlite occurrence: in the Early Cretaceous, radial extension was replaced by shearing. Both stages are related to opening of the central segment of theSouth Atlantic. The main kimberlite magmas occurred during the break-up of the Angola-Brazilian segment of Gondwana. In the course of all the four stages, stress was mainly released by the NE- and E-NE-striking faults and, to a lesser extent, by the NW-striking and latitudinal faults. The initial stage of kimberlite magmatism is associated with the NE- and E-NE-striking faults due to the presence of the Precambrian zones of flow and schistosity, which facilitated the NW-trending subhorizontal extension. Stage 5 (NE compression) began in the second half of the Cretaceous and possibly lasted until the end of the Paleogene, and compression occurred mainly along the NW-striking faults. Regionally, it corresponds to two stages of inversion movements in the southern regions of Africa, during which theAngoladome-shaped uplift emerged and the shoulders of the East African rifts began to take shape. Stage 6 (horizontal extension, mainly in the N-NE direction) is related to the processes that took place in the southern segment of theTanganyikarift and the eastern coast of theAtlantic. Based on the results of our studies, it became for the first time possible to get an idea of the main stages in the evolution of the studied region. Further geostructural measurements and dating of the host rocks will provide for a more precise definition of the proposed stages.
DS1991-0581
1991
Glasmacher, U.Glasmacher, U.Gold bearing sulfide veins in shoshonites, formed by high -T, high -Clalkaline fluids, Prospector Mtn. Yukon TerritoryGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC)/SEG Annual Meeting May 27-29. Toronto, Ontario, Abstract, Vol. 16, p. A46. AbstractYukonShoshonites, Alkaline rocks
DS201012-0041
2010
Glasmacher, U.A.Bauer, F.U., Glasmacher, U.A., Malikwisha, M., Mambo, V.S., Mutete, B.V.The eastern Congo - a beauty spot, rediscovered from a geological point of view.Geology Today, Vol. 26, 2, pp. 55-64.Africa, Democratic Republic of CongoHistory
DS201801-0007
2018
Glasmacher, U.A.Bunge, H-P., Glasmacher, U.A.Models and observations of vertical motion ( MoveOn) associated with rifting to passive margins. PrefaceGondwana Research, Vol. 53, 1, pp. 1-8.Mantlerifting

Abstract: Two recent co-ordinated research programs - the SAMPLE (South Atlantic Margin Processes and Links with onshore Evolution) program of the German Science Foundation and the French Topo-Africa program - have focused attention on the interaction of the lithosphere with sublithospheric processes. With a main thrust on the West-Gondwana break up and the subsequent post-rift evolution of the South Atlantic passive margins and their hinterlands, SAMPLE and Topo-Africa made concerted efforts to advance models and observations of vertical motions (MoveOn) in the South Atlantic region as a probe into mantle convection/lithosphere interaction. In this special issue of Gondwana Research we assemble a set of contributions that stem from these programs aimed to gain insights on rifting in a geodynamic context with a particular focus on models and observations of the vertical motions of the lithosphere induced by mantle flow. Anderson (1982) suggested that breakup of the supercontinent Gondwana owed to forces in the sublithospheric mantle. However, despite much progress in mantle flow modeling (see Zhong and Liu, 2016 for a recent review), linking mantle convection forces and motion of the lithosphere in quantitative terms has remained elusive. It is generally accepted that plate tectonics is a surface expression of mantle convection and that mantle flow drives horizontal plate motion (Davies, 1999). However, plate tectonic motion reflects a balance of poorly known sublithospheric forces related to mantle flow, and of shallow plate-boundary forces (see Iaffaldano and Bunge, 2015 for a recent review). The latter involve topographic loads from mountain belts and fault friction along convergent plate boundaries (Iaffaldano and Bunge, 2009). Rates of change of plate velocities connect to changes in orogenic topography (Iaffaldano et al., 2006; Austermann and Iaffaldano, 2013) or plate boundary strength (Iaffaldano, 2012), making it possible to reduce some uncertainty on plate boundary forces from the analysis of plate motion changes. But the superposition of sublithospheric forces and shallow plate-boundary forces inhibits interpretations of horizontal plate motions solely in terms of mantle flow related forces. It is also believed that substantial vertical deflections of the earth's surface are induced by viscous stresses from the mantle (e.g., Pekeris, 1935). Such deflections were recognized early on in the sedimentary record through unconformities and missing sections (e.g., Stille, 1919, 1924). Termed ‘Dynamic Topography’ by Hager et al. (1985) > 30 years ago, this topic has received much attention lately (see Braun, 2010 for a recent review). The essential role of dynamic topography in dynamic earth models is well understood, because the mass anomalies associated with surface deflections yield gravity anomalies of comparable amplitude to the flow inducing mantle density variations. Therefore, Geoid interpretations have long been performed with dynamic earth models that account for dynamic topography as well as mantle density heterogeneity (e.g., Ricard et al., 1984; Richards and Hager, 1984; Forte and Mitrovica, 2001). The dynamic topography response of earth models to internal loads (e.g., hot rising plumes or cold sinking slabs) is commonly expressed through kernels (see Colli et al., 2016, for a recent review). They imply that the earth's surface sustains deflections on the order of ± 1 km. For a plume rising through a uniform viscosity mantle the kernels predict the deflections to grow continuously during plume ascend. This is borne out in laboratory models of isoviscous mantle flow (Griffith et al., 1989). However, in the presence of a weak upper mantle much of the surface deflection develops in the final phase of the plume ascend, in a time span of a few million years (Myrs) associated with vertical transit of the plume through the low viscosity upper mantle (Fig. 1). This makes rapid surface uplift events geodynamically plausible.
DS201903-0502
2019
Glasmacher, U.A.da Silva, B.V., Hackspacher, P.C., Siqueira Riberio, M.C., Glasmacher, U.A., Goncalves, A.O., Doranti-Tiritan, C., de Godoy, D.F., Constantino, R.R.Evolution of the southwestern Angolan margin: episodic burial and exhumation is more realistic than long term denudation.International Journal of Earth Sciences, Vol. 108, pp. 89-113.Africa, Angolathermochronology

Abstract: There are two main points of view regarding how continental margins evolve. The first one argues that the present-day margins have been developed by long-term denudation since a major exhumation episode, probably driven by rifting or another relevant tectonic event. The second one argues that continental margins underwent alternating burial and exhumation episodes related to crustal tectonic and surface uplift and subsidence. To demonstrate that the proximal domain of the southwestern Angolan margin has evolved in a polycyclic pattern, we present a review of geological and thermochronological information and integrate it with new combined apatite fission-track and (U-Th)/He data from Early Cretaceous volcanic and Precambrian basement samples. We also provide hypotheses on the possible mechanisms able to support the vertical crustal movements of this margin segment, which are also discussed based on some modern rifting models proposed for Central South Atlantic. The central apatite fission-track ages range from 120.6?±?8.9 to 272.9?±?21.6 Ma, with the mean track lengths of approximately 12 µm. The single-grain apatite (U-Th)/He ages vary between 52.2?±?1 and 177.2?±?2.6 Ma. The integration of the thermochronological data set with published geological constraints supports the following time-temperature evolution: (1) heating since the Carboniferous-Permian, (2) cooling onset in the Early Jurassic, (3) heating onset in the Early Cretaceous, (4) cooling onset in the Mid- to Late Cretaceous, (5) heating onset in the Late Cretaceous, and (6) cooling onset in the Oligocene-Miocene. The thermochronological data and the geological constraints, support that the proximal domain of the southwestern Angolan margin was covered in the past by pre-, syn-, and post-rift sediments, which were eroded during succeeding exhumation events. For this margin segment, we show that a development based on long-term denudation is less realistic than one based on burial and exhumation episodes during the last 130 Myr.
DS200412-1836
2004
Glass, B.P.Simonson, B.M., Glass, B.P.Spherule layers - records of ancient impacts.Annual Review of Earth and Planetary Sciences, Vol. 32, May pp. 329-361.TechnologyOverview - spherule layers, geologic age
DS201212-0247
2012
Glass, B.P.Glass, B.P., Simonson, B.M.Distal impact ejecta layers: spherules and more.Elements, Vol. 8, 1, Feb. pp. 43-48.MantleEjecta
DS1990-0839
1990
Glass, C.E.King, T.A., Glass, C.E., Schowengerdt, R.A.Multispectral ratio selection using Ternary diagramsAssociation Eng. Geologist Bulletin, Vol. 27, No. 1, pp. 93-102ArizonaAlteration, Remote Sensing
DS200812-0812
2008
Glass, C.W.Oganov, A.R., Ono, S., Ma, Y., Glass, C.W., Garcia, A.Novel high pressure structures of MgCo3, CaCo3 and CO2 and their role in Earth's lower mantle.Earth and Planetary Science Letters, Vol. 273, pp. 38-47.MantleUHP, Carbon storage
DS1983-0257
1983
Glass, G.B.Glass, G.B.Minerals Outlook for WyomingWyoming Geological Survey Pamphlet., SEPTEMBER, 21P. ALSO Vol. 1, No. 4, DECEMBER , 31P.United States, Wyoming, Colorado, State Line, Rocky MountainsCurrent Activities
DS1984-0305
1984
Glass, G.B.Glass, G.B.Metallic Minerals Section of WyomingFifty First Annual Report of The Geological Survey Wyoming, JUNE 30TH. PP. 15-17.United States, Wyoming, Colorado, State LineSheep Rock, Sybille Canyon, Happy Jack Pole Mountain
DS1989-0517
1989
Glass, G.B.Glass, G.B., Bruhnke, S.G.Brief notation : field and laboratory investigations of potentially Diamond bearing kimberlites and other rocks.. ongoing -more than 100 possible pipesrecognizGeological Survey of Wyoming, 56th. Annual Report, Notation as title -full, p. 11. Brief as above in titleWyomingNews item, Diamond research
DS201112-0704
2011
Glass, H.J.Muhammad, K., Glass, H.J.Modelling short scale variability and uncertainty during mineral resource estimation using a novel fuzzy estimation technique.Geostandards and Geoanalytical Research, In press availableTechnologyResource estimation
DS201112-0705
2011
Glass, H.J.Muhammed, K., Glass, H.J.Modelling short scale variability and uncertainty during mineral resource estimation using a novel fuzzy estimation technique.Geostandards and Geoanalytical Research, Vol. 35, 3, pp. 369-385.TechnologyMineral grades - not specific to diamonds
DS1940-0030
1941
Glass, J.J.Miser, H.D., Glass, J.J.Fluorescent Sodalite and Hackmanite from Magnet Cove, Arkansas.American MINERALOGIST., Vol. 26, No. 7, PP. 437-445.United States, Gulf Coast, Arkansas, Hot Spring CountyMineralogy
DS1989-1629
1989
Glass, J.T.Williams, B.E., Glass, J.T.Characterization of diamond thin films - diamond phaseidentification, surface morphology and defectstructuresJournal of Mater. Res, Vol. 4, No. 2, Mar-Apr pp. 373-384GlobalDiamond morphology, CVD.
DS1990-0578
1990
Glass, J.T.Glass, J.T., Messier, R., Fujimori, N.Diamond, silicon carbide and related wideband gap semiconductors.Symposium held Nov. 1989 BostonMaterials Research Society, Vol. 162, 650p. Table of contents availableGlobalMaterials research, Diamond uses electronics
DS200912-0317
2005
Glasser, N.F.Hubbard, B., Glasser, N.F.Field techniques in glaciology and glacial geomorphology.Wiley Blackwell, $ 70.00 425p. now in paperback 2009GlobalBook - glaciology
DS1999-0253
1999
Glasser, S.M.Glasser, S.M., Foley, S.F., Gunther, D.Trace element compositions of minerals in garnet and spinel peridotite xenoliths from the Vitim volcanicsLithos, Vol. 48, No. 1-4, Sept. pp. 263-86.Russia, Siberia, BaikalXenoliths, Volcanic field
DS201608-1409
2016
Glassley, W.Glassley, W.Na-P concentrations in high-pressure garnets: a potentially rich, but risky P-T repository.American Mineralogist, Vol. 101, p. 1718.TechnologyUHP - garnets

Abstract: Establishing the history of HP and UHP metamorphic rocks is important for quantifying Earth dynamics. The history of these rocks defines, among other things, paleo-subduction rates, P-T paths, and the kinematics of continent-continent collision. Although the appearance of certain minerals, such as coesite, stishovite, or diamond, provides unequivocal evidence of an HP or UHP component to the history of a rock, they cannot provide details of the P-T-t path a rock has experienced. However, complex solid solutions can. This reflects the fact that solid solutions have the potential to provide a continuous thermodynamically controlled response to evolving P-T conditions. To the extent that such solid-solution characteristics are preserved unmodified in a mineral throughout its history, a detailed description of the trajectory of the rock during burial …
DS201803-0452
2018
Glassley, W.E.Glassley, W.E.Epiphanies of the edgelands. Book: A wilder time: notes from a geologist at the edge of the Greenland ice.Nature, Vol. 554, Feb 8, p. 166.Europe, Greenlandgeomorphology
DS1994-0626
1994
Glasson, K.Glasson, K., Webb, B.Industry exploration practice.The Australian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 1, February, p. 24AustraliaMining, Public awareness
DS1997-0420
1997
Glatiotis, A.C.Glatiotis, A.C.Metallic and industrial mineral assessment report on the Endiang properties for diamond potential.Alberta Geological Survey, MIN 19970013, 134p. 2 maps.AlbertaExploration - assessment
DS1993-0550
1993
Glatzmaier, G.A.Glatzmaier, G.A., Schubert, G.Three dimensional shpherical models of layered and whole mantleconvection.Journal of Geophysical Research, Vol. 98, No. B 12, December 10, pp. 21, 969-21, 976.MantleGeodynamics, Mantle convection
DS200812-0814
2008
Glatzmaier, G.A.Ogden, D.E., Glatzmaier, G.A.Effects of vent overpressure on buoyant eruption columns: implications for plume stability.Earth and Planetary Science Letters, Vol. 268, no. 3-4, April. 30, pp. 283-292.MantleGeophysics
DS1990-0579
1990
Glatzmaler, G.A.Glatzmaler, G.A., Schubert, G., Bercovci, D.Chaotic subduction like downflows in a spherical model of convection in theearth's mantleNature, Vol. 347, No. 8290, September 20, pp. 274-277GlobalMantle, Subduction-convection
DS1990-0946
1990
Glaves, H.M.Lofty, G.J., Hillier, J.A., Burton, E.M., Cooke, S.A., Glaves, H.M.Diamond. Production, Exports, importsBritish Geological Survey World Mineral Statistics, 1984-1988, 6pGlobalDiamond production, Economics
DS1998-1387
1998
GlazeSparks, R.S.J., Bursik, Carey. Gilbert, GlazeVolcanic plumesJohn Wiley, 570pGlobalBook - table of contents, volcanism, fluid dynamics, eruptions
DS1989-0319
1989
Glazner, A.F.Curtis, P.C., Meen, J.K., Glazner, A.F.Liquid lines of descent in alkalic continental riftmagmas; petrologic, geochemical, and experimental constraints from the East African riftNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 65. AbstractEast Africa, KenyaTectonics
DS1991-0995
1991
Glazner, A.F.Lipman, P.W., Glazner, A.F.Introduction to Middle Tertiary Cordilleran volcanic magma sources and relations to regional tectonicsJournal of Geophysical Research, Vol. 96, No. B8, July 30, pp. 13, 193-13, 200CordilleraVolcanics, Tectonics
DS1994-0627
1994
Glazner, A.F.Glazner, A.F.Foundering of mafic plutons and density stratification of continentalcrustGeology, Vol. 2, No. 5, May pp. 435-438GlobalStratigraphy
DS1999-0049
1999
Glazner, A.F.Beard, B.L., Glazner, A.F.Petrogenesis of isotopically unusual Pliocene olivine leucitites from Dee Springs Valley, California.Contributions to Mineralogy and Petrology, Vol. 133, pp. 402-417.CaliforniaMagma - potassic, Subduction
DS2000-0612
2000
Glazner, A.F.Manley, C.R., Glazner, A.F., Farmer, G.L.Timing of volcanism in the Sierra Nevada of California: evidence for Pliocene delamination of batholithic rootGeology, Vol. 28, No. 9, Sept. pp. 811-14.CaliforniaTectonics, Magmatism - alkaline
DS200412-0672
2004
Glazner, A.F.Glazner, A.F., Bartley, J.M., Coleman, D.S., Gray, W., Taylor, R.Z.Are plutons assembled over millions of years by amalgamation from small magma chambers?Geology Today, Vol. 14, 4, pp. 4-11.TechnologyMagmatism - not specific to diamonds
DS200612-0470
2006
Glazner, A.F.Glazner, A.F., Bartley, J.M.Is stoping a volumetrically significant pluton emplacement process?Geological Society of America Bulletin, Vol. 118, 9, Sept. pp. 1185-1195.MantleIgneous petrology, structure, tectonics, xenoliths
DS200612-1500
2006
Glazner, A.F.Walker, J.D., Bowers, T.D., Black, R.A., Glazner, A.F., Farmer, G.L., Carlson, R.W.A geochemical database for western North American volcanic and intrusive rocks. NAVDATIn: Sinha, A.K. Geoinformatics: data to knowledge, GSA Special Paper, 397, 397, pp.61-72United StatesGeochemistry - data
DS201605-0861
2016
Glazner, A.F.Lundstrom, C.C., Glazner, A.F.Enigmatic relationship between silicic volcanic and plutonic rocks: silicic magmatism and the volcanic-plutonic connection.Elements, Vol. 12, pp. 91-96.TechnologyMagmatism
DS201610-1864
2016
Glazner, A.F.Glazner, A.F., Bartley, J.M., Coleman, D.S.We need a new definition of magma.EOS Transaction of AGU, Sept. 22, 3p.TechnologyDefinition of magma
DS1996-0047
1996
Glaznev, V.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
DS1997-0044
1997
Glaznev, V.Arzamastsev, A., Belyatsky, B., Glaznev, V.Paleozoic alkaline intrusions of the Kola Peninsula, Russia: subsurface structure and their mantle roots...Geological Association of Canada (GAC) Abstracts, Russia, Kola PeninsulaCarbonatite, Mantle xenoliths
DS2000-0026
2000
Glaznev, V.N.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
DS2001-0051
2001
Glaznev, V.N.Arzamastsevm A.A., Bea, F., Glaznev, V.N., Arzamasteva, L.V., Montero, P.Kola alkaline province in the Paleozoic: evaluation of primary mantle magma composition and magma generation conditions.Russian Journal of Earth Science, Vol. 3, 1, March, pp.Russia, Kola PeninsulaMagmatism
DS200412-0087
2004
Glaznev, V.N.Balashov, Yu.A., Glaznev, V.N.The impact of plume magmatism on the dyanmics of Precambrian crust formation.Doklady Earth Sciences, Vol. 394, 2, Feb-Mar. pp. 170-173.TechnologyMagmatism
DS200512-0058
2004
Glaznev, V.N.Balashov, Yu.A., Glaznev, V.N.Mantle cycles: a modern insight.Deep seated magmatism, its sources and their relation to plume processes., pp. 68-95.MantleModels
DS200612-0077
2006
Glaznev, V.N.Balashov, Yu.A., Glaznev, V.N.Endogenic cycles and the problem of crustal growth.Geochemistry International, Vol. 44, 2, pp. 109-117.MantleTectonics
DS200612-0078
2005
Glaznev, V.N.Balashov, Yu.A., Glaznev, V.N.Cycles of alkaline magmatism.Geochemistry International, Vol. 44, 3, pp. 274-285.RussiaMagmatism
DS200812-0049
2008
Glaznev, V.N.Arzamastev, A.A., Glaznev, V.N.Plume lithosphere interaction in the presence of an ancient sublithospheric mantle keel: an example from the Kola alkaline province.Doklady Earth Sciences, Vol. 419A, no. 3, pp. 384-387.Russia, Kola PeninsulaMantle plume
DS200812-0414
2008
Glaznev, V.N.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
DS201412-0019
2014
Glaznev, V.N.Arzamastsev, A.A., Arzamasteva, L.V., Zhirova, A.M., Glaznev, V.N.Model of formation of the Khibiny-Lovozero ore bearing volcanic-plutonic complex.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 124-147.RussiaModelling
DS201412-1029
2014
Glaznev, V.N.Zhirov, D.V., Glaznev, V.N., Zhirova, A.M.Structure of upper crust of the Khibiny area on the basis of the geological and geophysical dat a and results of 3D seismic and density modeling.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, RussiaGeophysics
DS201510-1757
2014
Glaznev, V.N.Arzamastev, A.A., Arztmasteva, L.V., Zhirova, A.M., Glaznev, V.N.Model of formation of the Khibiny-Lovozero ore bearing volcanic-plutonic complex.Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 124-147.Baltic Shield, FennoscandiaCarbonatite, alkaline rocks

Abstract: The paper presents the results of a study of the large Paleozoic ore-magmatic system in the northeastern Fennoscandian Shield comprising the Khibiny and Lovozero plutons, the Kurga intrusion, volcanic rocks, and numerous alkaline dike swarms. As follows from the results of deep drilling and 3D geophysical simulation, large bodies of rocks pertaining to the ultramafic alkaline complex occur at the lower level of the ore-magmatic system. Peridotite, pyroxenite, melilitolite, melteigite, and ijolite occupy more than 50 vol % of the volcanic-plutonic complex within the upper 15 km accessible to gravity exploration. The proposed model represents the ore-magmatic system as a conjugate network of mantle magmatic sources localized at different depth levels and periodically supplying the melts belonging to the two autonomous groups: (1) ultramafic alkaline rocks with carbonatites and (2) alkali syenites-peralkaline syenites, which were formed synchronously having a common system of outlet conduits. With allowance for the available isotopic datings and new geochronological evidence, the duration of complex formation beginning from supply of the first batches of melt into calderas and up to postmagmatic events, expressed in formation of late pegmatoids, was no less than 25 Ma.
DS1994-0628
1994
Glazov, E.A.Glazov, E.A., Felitzyn, S.B.Miner agenic methods of estimation for diamonds of the northwestern part Of the Russian Platform10th. Prospecting In Areas Of Glaciated Terrain, p. 155-156. AbstractRussiaGeochemistry, Exploration prospecting
DS2001-0397
2001
GlazunovGornova, M.A., Solovjeva, L.V., Glazunov, BelozerovaFormation of Precambrian lithosphere mantle geochemical analysis of coarseAlkaline Magmatism -problems mantle source, pp. 223-41.Russia, SiberiaCraton, Geochemistry
DS1984-0306
1984
Glazunov, O.M.Glazunov, O.M., Zolotina, M.A., Tatarinov, A.V.Garnet Pyroxenites of East SayanSoviet Geology And Geophysics, Vol. 25, No. 7, PP. 72-76.Russia, NorwayEclogites, Mineral Chemistry, Websterite, Kitoi Mountains
DS2000-0353
2000
Glazunov, O.M.Gornova, M.A., Glazunov, O.M.Mantle peridotites and pyroxenites of the Saramanta Massif in the Precambrian gneiss granitoid complex.Russian Geology and Geophysics, Vol. 40, No. 7, pp. 986-999.RussiaPeridotites
DS200512-0354
2001
Glazunov, O.M.Gornova, M.A., Solovjeva, L.V., Glazunov, O.M., Belozerova, O.Yu.Formation of Precambrian lithosphere mantle - geochemical analysis of coarse grained peridotites from kimberlites, Siberian Craton.Alkaline Magmatism and the problems of mantle sources, pp. 223-241.Russia, SiberiaGeochemistry
DS200612-0449
2006
Glazunov, O.M.Gertner, I.F., Glazunov, O.M., Vrublevskii, V.V., Krasnova, T.S., Tishin, P.A.Geochemical and isotopic constraints for the formation model of the Kingash ultramafic and mafic complex, eastern Sayan ridge, central Siberia.Vladykin: VI International Workshop, held Mirny, Deep seated magmatism, its sources and plumes, pp. 188-206.Russia, SiberiaGeochronology
DS1983-0445
1983
Glazunova, A.D.Mekhonoshin, A.S., Glazunova, A.D., Frolova, L.P., Klopotov, V.Geochemical Features of Ilmenite of Basic and Ultrabasic Rocks.Soviet Geology And Geophysics, Vol. 24, No. 4, PP. 55-60.RussiaGeochemistry
DS201112-0698
2011
Glazyrin, K.Mookerjee, M., Nakajima, Y., Steinle-Neumann, G., Glazyrin, K., Wu, X., Dubrovinsky, McCammon, ChumakovHigh pressure behaviour of iron carbide (Fe[7]C[3j] at inner core conditions.Journal of Geophysical Research, Vol. 116, B4, B04201.MantleHP core
DS201212-0078
2012
Glazyrin, K.Boffa Ballaran, T., Kurosov, A., Glazyrin, K., Frost, D.J., Merlini, M., Hanfland, M., Caracas, R.Effect of chemistry on the compressibility of silicate perovskite in the lower mantle.Earth and Planetary Science Letters, Vol. 333-334, pp. 181-190.MantlePerovskite
DS201412-0297
2014
Glazyrin, K.Glazyrin, K., Boffa Ballaran, T., Frost, D.J., McCammon, C., Kantor, A., Merlini, M., Hanfland, M., Dubrovinsky, L.Magnesium silicate perovskite and effect of iron oxidation state on its bulk sound velocity at the conditions of the lower mantle.Earth and Planetary Science Letters, Vol. 393, pp. 182-186.MantlePerovskite
DS201412-0566
2013
Glazyrin, K.McCammon, C., Glazyrin, K., Kantor, A., Kantor, I., Kupenko, I., Narygina, O., Potapin, V., Vasily, P., Sinmyo, C., Chumakov, Ruffer, Sergueev, Smirnov, DubrovinskyIron spin state in silicate perovskite at conditions of Earth's deep interior.International Journal of High Pressure Research, Vol. 33, 3, pp. 663-672.MantlePerovskite
DS201504-0213
2015
Glazyrin, K.Prescher, C., Dubrovinsky, L., Bykova, E., Kupenko, I., Glazyrin, K.High Poisson's ration of Earth's inner core explained by carbon alloying.Nature Geoscience, Vol. 8, 3, pp. 220-223.MantleCore, carbon
DS1989-0021
1989
GleadowAllsopp, H.L., Bristow, J.W., Smith, C.B., Brown, R., GleadowA summary of radiometric dating methods applicable To kimberlites and realted rocksGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 343-357Southern AfricaAge emplacement, Radiometric, Geochronolog
DS1989-0540
1989
GleadowGreen, P.F., Duddy, I.R., Leslett, G.M., Hegarty, K.A., GleadowThermal annealing of fission tracks in apatite, 4. Quantitative modelling techniques and extension to geological timescalesChemical Geology, Vol. 79, No. 2, August 1, pp. 155-GlobalGeochronology, Timescales
DS200712-0452
2006
GleadowHu, 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
DS200912-0071
2009
GleadowBraun, J., Burbidge, D.R., Gesto, Sandford, Gleadow, Kohn, CumminsConstraints on the current rate of deformation and surface uplift of the Australian continent from a new seismic database and low T thermochronological data.Australian Journal of Earth Sciences, Vol. 56, 2, pp. 99-110.AustraliaGeophysics - seismic
DS1996-0182
1996
Gleadow, A.Brown, R., Gallagher, K., De Wit, M., Gleadow, A.The Cratonic conundrum: does old+cold+thick=stable?Australia Nat. University of Diamond Workshop July 29, 30. abstract, 1p.South Africa, BrazilCraton, Paleotemperatures
DS201502-0046
2014
Gleadow, A.Brown, R., Summerfield, M., Gleadow, A., Gallagher, K., Carter, A., Beucher, R., Wildman, M.Intracontinental deformation in southern Africa during the Late Cretaceous.Journal of African Earth Sciences, Vol. 100, pp. 20-41.Africa, NamibiaGeothermometry

Abstract: Intracontinental deformation accommodated along major lithospheric scale shear zone systems and within associated extensional basins has been well documented within West, Central and East Africa during the Late Cretaceous. The nature of this deformation has been established by studies of the tectonic architecture of sedimentary basins preserved in this part of Africa. In southern Africa, where the post break-up history has been dominated by major erosion, little evidence for post-break-up tectonics has been preserved in the onshore geology. Here we present the results of 38 new apatite fission track analyses from the Damara region of northern Namibia and integrate these new data with our previous results that were focused on specific regions or sections only to comprehensively document the thermo-tectonic history of this region since continental break-up in the Early Cretaceous. The apatite fission track ages range from 449 ± 20 Ma to 59 ± 3 Ma, with mean confined track lengths between 14.61 ± 0.1 ?m (SD 0.95 ?m) to 10.83 ± 0.33 ?m (SD 2.84 ?m). The youngest ages (c. 80–60 Ma) yield the longest mean track lengths, and combined with their spatial distribution, indicate major cooling during the latest Cretaceous. A simple numerical thermal model is used to demonstrate that this cooling is consistent with the combined effects of heating caused by magmatic underplating, related to the Paraná-Etendeka continental flood volcanism associated with rifting and the opening of the South Atlantic, and enhanced erosion caused by major reactivation of major lithospheric structures within southern Africa during a key period of plate kinematic change that occurred in the South Atlantic and SW Indian ocean basins between 87 and 56 Ma. This phase of intraplate tectonism in northern Namibia, focused in discrete structurally defined zones, is coeval with similar phases elsewhere in Africa and suggests some form of trans-continental linkage between these lithospheric zones.
DS201712-2702
2017
Gleadow, A.Mackintosh, V., Kohn, B., Gleadow, A., Tian, Y.Phanerozoic morphotectonic evolution of the Zimbabwean craton: unexpected outcomes from a multiple low temperature thermochronology study.Tectonics, Vol. 36, 10, in press availableAfrica, Zimbabwecraton, geothermometry

Abstract: The fragmentary Phanerozoic geological record of the anomalously elevated Zimbabwe Craton makes reconstructing its history difficult using conventional field methods. Here we constrain the cryptic Phanerozoic evolution of the Zimbabwe Craton using a spatially extensive apatite (U-Th-Sm)/He (AHe), apatite fission track (AFT), and zircon (U-Th)/He (ZHe) data set. Joint thermal history modeling reveals that the region experienced two cooling episodes inferred to be the denudational response to surface uplift. The first and most significant protracted denudation period was triggered by stress transmission from the adjacent ~750-500 Ma Pan-African orogenesis during the amalgamation of Gondwana. The spatial extent of this rejuvenation signature, encompassing the current broad topographic high, could indicate the possible longevity of an ancient topographic feature. The ZHe data reveal a second, minor denudation phase which began in the Paleogene and removed a kilometer-scale Karoo cover from the craton. Within our data set, the majority of ZHe ages are younger than their corresponding AHe and AFT ages, even at relatively low eU. This unexpectedly recurrent age “inversion” suggests that in certain environments, moderately, as well as extremely, damaged zircons have the potential to act as ultra-low-temperature thermochronometers. Thermal history modeling results reveal that the zircon radiation damage accumulation and annealing model (ZRDAAM) frequently overpredicts the ZHe age. However, the opposite is true for extremely damaged zircons where the ZHe and AHe data are also seemingly incompatible. This suggests that modification of the ZRDAAM may be required for moderate to extreme damage levels.
DS202203-0336
2022
Gleadow, A.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.
DS2002-0579
2002
Gleadow, A.J.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
DS1975-0722
1978
Gleadow, A.J.W.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
DS1975-0749
1978
Gleadow, A.J.W.Gleadow, A.J.W., Edwards, A.C.Mineralogical Note: Fission Track Age of a Basic Inclusion from the kayrunnera Kimberlitic Breccia Pipe.Geological Society AUST. Journal, Vol. 25, PP. 323-340; P. 359.Australia, New South WalesKimberlite
DS1993-0452
1993
Gleadow, A.J.W.Foster, D.A., Gleadow, A.J.W.Episodic denudation in East Africa: a legacy of intracontinentaltectonism.Geophysical Research Letters, Vol. 20, No. 21, November 5, pp. 2395-2398.East Africa, Kenya, TanzaniaTectonics, Isostacy, Thermochronology
DS1997-0854
1997
Gleadow, A.J.W.Noble, W.P., Fosterm D.A., Gleadow, A.J.W.The Post Pan African thermal and extensional history of crystalline basement rocks in eastern TanzaniaTectonophysics, Vol. 275, No. 4, July 20, pp. 313-330TanzaniaTectonics, Geothermometry
DS2002-0870
2002
Gleadow, A.J.W.Kohn, B.P., Gleadow, A.J.W., Brown, R.W., Gallagher, K., O'Sullivan, P.B.Shaping the Australian crust over the last 300 million years: insights from fission trackAustralian Journal of Earth Sciences, Vol. 49,4,August pp. 697-718.AustraliaTectonics, Geothermometry
DS200512-0656
2004
Gleadow, A.J.W.Lorencak, M., Kohn, B.P., Osadetz, K.G., Gleadow, A.J.W.Combined apatite fission track and U Th/He thermochronology in a slowly cooled terrane: results from a 3440 m deep drill hole in the southern Canadian shield.Earth and Planetary Science Letters, Vol. 227, 1-2, Oct. 30, pp. 87-104.Canada, OntarioSudbury Igneous Complex shield
DS200512-1171
2005
Gleadow, A.J.W.Weber, U.D., Kohn, B.P., Gleadow, A.J.W., Nelson, D.R.Low temperature Phanerozoic history of the northern Yilgarn Craton, western Australia.Tectonophysics, Vol. 400, 1-4, May 11, pp. 127-151.AustraliaGeothermometry
DS200712-0561
2007
Gleadow, A.J.W.Kohlmann, F., Kohn, B.P., Gleadow, A.J.W., Osadetz, K.G.Low temperature thermochronology of Phanerozoic kimberlites and Archean basement, Slave Province, Canada.Plates, Plumes, and Paradigms, 1p. abstract p. A505.Canada, Northwest TerritoriesGeothermometry - Ekati, Jericho, Muskox
DS1996-0461
1996
Gleadow, J.W.Foster, D.A., Gleadow, J.W.Structural framework and denudation history of the flanks of the Kenya and Anza Rifts, East Africa.Tectonics, Vol. 15, No. 2, Apr. pp. 258-71.Kenya, East AfricaTectonics, Rifting
DS1990-0617
1990
Gleason, J.Guo, W.X., Friedman, I., Gleason, J.Natural occurrence of silicon carbide in a Diamondiferous kimberlite fromFuxianNature, Vol. 346, No. 6282, July 26, pp. 352-354ChinaSilicon carbide, Mineralogy
DS1990-0921
1990
Gleason, J.Leung, I.S. , Guo, WX, Friedman, I., Gleason, J.Natural occurrence of silicon-carbide in a Diamondiferous kimberlite fromFuxianNature, Vol. 346, No. 6282, July 26, pp. 352-354ChinaDiamond genesis -Silicon carbide, Mineralogy -kimberlite
DS1990-0922
1990
Gleason, J.Leung, I.S., Friedman, I., Gleason, J.Evidence of silicon carbide diamond paragenesis:implications for carbon isotopic composition of themantleEos, Vol. 71, No. 17, April 24, p. 644 Abstract onlyChinaDiamond genesis, Geochronology -carbon
DS1989-0230
1989
Gleason, J.D.Castor, S.B., Gleason, J.D.Proterozoic ultrapotassic intrusive rocks in southeastern CaliforniaGeological Society of America (GSA) Abstract Volume, Vol. 21, No. 5, p. 64. (abstract.)CaliforniaUltrapotassic ( Australia, Spain, Wyoming), Lamproite(?)
DS1988-0374
1988
Gleason, K.J.Krantz, W.B., Gleason, K.J., Caine, N.Patterned ground. a commmon physical phenomena shapes these uncommon manifestations of natural geometryScientific American, Vol. 259, No. 6, December pp. 68-76. Database # 17356Montana, ColoradoGeomorphology
DS1987-0409
1987
Glebova, Z.M.Levin, V.Ya., Levina, I.A., Glebova, Z.M., Dolzhanskaya, T.Yu.Mineralogy of carbonatites of the Buldym massif in the VishnevoeMountains.(Russian)Mineraly Mestorozhd. Urala, Sverd., (in Russian), pp. 117-123RussiaBlank
DS201212-0373
2012
Glebovitski, V.A.Koreshkova, M.Yu., Downes, H., Rodionov, N.V., Antonov, A.V., Glebovitski, V.A., Sergeev, S.A., Schukina, E.V.Trace element and age characteristics of zircons in lower crustal xenoliths from the Grib kimberlite pipe, Arkhangelsk province, Russia.emc2012 @ uni-frankfurt.de, 1p. AbstractRussia, Archangel, Kola PeninsulaDeposit - Grib
DS201012-0238
2010
Glebovitskii, R.V.A.Glebovitskii, R.V.A., Nikitina, L.P., Pushkarev, Y.D., Vrevskii, A.B., Goncharov, A.G., Bogomolov, E.S.Sm and Nd geochemistry of mantle xenoliths: the problem of mantle material classification.Doklady Earth Sciences, Vol. 433, 1, pp. 890-893.MantleMantle magmatism
DS2002-0580
2002
Glebovitskii, V.A.Glebovitskii, V.A., Baltybaev, S.K., Levchenkov, O.A., Berezhnaya, LevskiiAge, duration and Pt parameters of the multistage metamorphism of Svecofennides ofDoklady, Vol.385,June-July, pp. 483-7.Europe, Baltic shieldGeochronology - U Pb
DS200712-0364
2007
Glebovitskii, V.A.Glebovitskii, V.A., Nikitina, L.P., Saltykova, A.K., Pushkarev, Y.D., Ovchinnikov, Babushkina, AshchepkovThermal and chemical heterogeneity of the upper mantle beneath the Baikal Mongolia territory.Petrology, Vol. 15, 1, pp. 58-89.RussiaGeothermometry
DS1993-0551
1993
Glebovitsky, V.A.Glebovitsky, V.A., Drugova, G.M.Tectonothermal evolution of the western Aldan shield, SiberiaPrecambrian Research, Vol. 62, pp. 493-505GlobalTectonics, Geotectonics
DS1996-0535
1996
Glebovitsky, V.A.Glebovitsky, V.A.Correlation and geodynamic interpretation of the greatest events of Laurasia Archean and Proterozoic..Russian Geology and Geophysics, Vol. 37, No. 1, pp. 37-47RussiaGeodynamics, Archean
DS1998-0516
1998
Glebovitsky, V.A.Glebovitsky, V.A.The early Precambrian of Russia #2Harwood Academic Publishers, 260p. approx. $ 100. United StatesRussia, Baltic States, Ukraine, SiberiaBook - table of contents, Platform, shield, structure, tectonics
DS2003-0472
2003
Glebovitsky, V.A.Glebovitsky, V.A., Nikitina, L.P., Khiltova, V.Y.Thermal regimes in the lower crust from garnet orthopyroxene thermobarometry ofIzvestia Physics of the Solid Earth, Vol. 29, 12, pp. 1029-1043. Ingenta 1035425304Russia, mantleBlank
DS200412-0673
2003
Glebovitsky, V.A.Glebovitsky, V.A., Nikitina, L.P., Khiltova, V.Y.Thermal regimes in the lower crust from garnet orthopyroxene thermobarometry of lower crust xenoliths in kimberlite and alkali bIzvestia Physics of the Solid Earth, Vol. 29, 12, pp. 1029-1043. Ingenta 1035425304Russia, MantleGeothermometry
DS200412-0674
2004
Glebovitsky, V.A.Glebovitsky, V.A., Nikitina, L.P., Khitova, V.Y., Ovchinnikov, N.O.The thermal regimes of the upper mantle beneath Precambrian and Phanerozoic structures up to the thermobarometry dat a of mantleLithos, Vol. 74, 1-2, pp. 1-20.Russia, Siberia, Europe, China, Australia, South AmericaGeothermometry
DS200812-0415
2008
Glebovitsky, V.A.Glebovitsky, V.A., Khiltova, V.Y., Kozakov, I.K.Tectonics of the Siberian craton: interpretation of geological, geophysical geochronological and isotopic geochemical data.Geotectonics, Vol. 42, 1, pp. 8-20.RussiaTectonics
DS200812-0416
2007
Glebovitsky, V.A.Glebovitsky, V.A., Nikitin, L.P., Salitykova, A.K., Ovchinnikov, N.O., Babushkina, M.S., Egorov, AshchepkovCompositional heterogeneity of the continental lithospheric mantle beneath the Early Precambrian and Phanerozoic structures: evidence from mantle xenoliths.Geochemistry International, Vol. 45, 11, pp. 1077-1102.MantleKimberlites and basalts
DS200912-0253
2009
Glebovitsky, V.A.Glebovitsky, V.A., Nikitina, L.P., Vrevskii, A.B., Pushkarev, M.S., Babushkina, M.S.,Goncharov, A.G.Nature of chemical heterogeneity of the continental lithospheric mantle.Geochemistry International, Vol. 47, 9., Sept. pp. 857-881.MantleGeochemistry
DS201412-0472
2014
Glebovitsky, V.A.Koreshkova, M.Yu., Downes, H., Glebovitsky, V.A., Rodionov, N.V., Antonov, A.V., Sergeev, S.A.Zircon trace element characteristics and ages in granulite xenoliths: a key to understanding the age and origin of the lower crust, Arkhangelsk kimberlite province, Russia.Contributions to Mineralogy and Petrology, Vol. 167, pp. 973-980.Russia, Archangel, Kola PeninsulaDeposit - Grib
DS200612-0462
2005
Gleditsch, N.P.Gilmore, E., Gleditsch, N.P., Lujala, P., Rod, J.K.Conflict diamonds: a new dataset. Primary deposits have low probability of being the object of conflict.Conflict Management and Peace Science, Vol. 22, 3, pp. 257-272.GlobalLegal - conflict diamonds
DS2002-1588
2002
Gleeson, C.F.Thomas, R.D., Gleeson, C.F.Use of till geochemistry and mineralogy to outline areas underlain by Diamondiferous spessartite dike WawaExploration and Mining Geology, Vol. 9,No.3-4.pp. 215-32.Ontario, WawaGeochemistry, Diamond occurrences, dikes
DS2003-0297
2003
Gleeson, C.F.Crabtree, D.C., Gleeson, C.F.Results of the Spider 3 regional kimberlite indicator mineral and geochemistry surveyOntario Geological Survey Open File, No. 6097, 127p.Ontario, James Bay LowlandsGeochemistry - pp.7,8, 13-19.
DS200412-0382
2003
Gleeson, C.F.Crabtree, D.C., Gleeson, C.F.Results of the Spider 3 regional kimberlite indicator mineral and geochemistry survey carried out in the vicinity of the Upper AOntario Geological Survey Open File, No. 6097, 127p.Canada, Ontario, Attawapiskat, James Bay LowlandsGeochemistry - pp.7,8, 13-19.
DS1998-1613
1998
Gleeson, S.A.Yardley, B.W.D., Gleeson, S.A.Dry deep stable crust and its rheology: evidence from deep penetratingfluid.Geological Society of America (GSA) Annual Meeting, abstract. only, p.A393.NorwayRheology, Tectonics
DS201112-0373
2011
Gleeson, T.Gleeson, T., Smith, L., Moosdorf, N., Hartmann, J., Durr, H.H., manning, A.H., Van Beek, P.H., Jellinek, A.Mapping permeability over the surface of the Earth.Geophysical Research Letters, Vol. 38, L02401MantleGeophysics
DS200512-0014
1998
Glejbal, K.Andersen, A.C., Jorgensen, U.G., Nicolaisen, F.M., Sorensen, P.G., Glejbal, K.Spectral features of presolar diamonds in laboratory and in carbon star atmospheres.Astronomy and Astrophysics, Vol. 330, pp. 1080-1090.Meteorite
DS1992-0579
1992
Glen, H.W.Glen, H.W.Mass mining undergroundSouth African Institute of Mining and Metallurgy (IMM), 485pAustralia, southern Africa, GermanyBook -ad, Mining
DS1992-0580
1992
Glen, H.W.Glen, H.W.Mass mining underground. Book ad lists sections on design and planning for VCR block caving at Kimberley, support mining at Premier, Finsch MinesSouth African Institute of Mining and Metallurgy (IMM), 485p. totalSouth AfricaMining methods, Deposit - Kimberley, Finsch, Premier
DS1996-0967
1996
Glen, J.D.Miller, R.R., Glen, J.D., Jaspersen, F.Z., Karmokolias, Y.International joint ventures in developing countries - happy marriages?International Finance Corp., Disc. Paper, No. 29, 26pGlobalEconomics, Joint ventures
DS2002-0581
2002
Glen, J.M.G.Glen, J.M.G., Ponce, D.A.Large scale fractures related to inception of the Yellowstone hotspotGeology, Vol. 30, No. 7, July pp. 647-50.Idaho, Oregon, NevadaPaleomagnetics
DS200512-0345
2005
Glen, W.Glen, W.The origins and early trajectory of the mantle plume quasi-paradigm.Plates, Plumes, and Paradigms, pp. 91-118. ( total book 861p. $ 144.00)GlobalStructure - overview
DS1900-0556
1907
Glen Diamond SyndicateGlen Diamond SyndicateReport on Progress - Glen Ds 1907South Africa, Vol. 75, SEPT. 7TH. P. 647.Africa, South AfricaMining Engineering
DS1991-1352
1991
Glenister, D.A.Pienaar, H., Glenister, D.A.On a gift of diamonds from Cecil John Rhodes for services renderedXiii International Gemmological Conference Held South Africa, Stellenbosch, 2p.abstractSouth AfricaHistory, Diamond gift to Heathcliffe
DS200612-1362
2006
GlennStachel, T., Paulen, R., Prior, G., Micea, C., Cubbing, M., McConnell, GlennDiamond exploration in western sedimentary basin ( glacial processes, till sampling, geophysics)Calgary Mining Forum, April 28 Short Course # 3, NOTICE only meg.calgary.ab.caCanada, AlbertaExploration - program
DS201709-1990
2017
Glenn, D.R.Glenn, D.R., Fu, R.R., Kehayias, P., Le Sage, D., Lima, E.A., Weiss, B.P., Walsworth, R.L.Micrometer-scale magnetic imaging of geological samples using a quantum diamond microscope. ( remnant magnetism meteorites)Geochemistry, Geophysics, Geosystems: G3, in press availableTechnologygeophsyics - magnetics

Abstract: Remanent magnetization in geological samples may record the past intensity and direction of planetary magnetic fields. Traditionally, this magnetization is analyzed through measurements of the net magnetic moment of bulk millimeter to centimeter sized samples. However, geological samples are often mineralogically and texturally heterogeneous at submillimeter scales, with only a fraction of the ferromagnetic grains carrying the remanent magnetization of interest. Therefore, characterizing this magnetization in such cases requires a technique capable of imaging magnetic fields at fine spatial scales and with high sensitivity. To address this challenge, we developed a new instrument, based on nitrogenvacancy centers in diamond, which enables direct imaging of magnetic fields due to both remanent and induced magnetization, as well as optical imaging, of room-temperature geological samples with spatial resolution approaching the optical diffraction limit. We describe the operating principles of this device, which we call the quantum diamond microscope (QDM), and report its optimized image-area-normalized magnetic field sensitivity (20 µT?µm/Hz½), spatial resolution (5 µm), and field of view (4 mm), as well as trade-offs between these parameters. We also perform an absolute magnetic field calibration for the device in different modes of operation, including three-axis (vector) and single-axis (projective) magnetic field imaging. Finally, we use the QDM to obtain magnetic images of several terrestrial and meteoritic rock samples, demonstrating its ability to resolve spatially distinct populations of ferromagnetic carriers.
DS1910-0051
1910
Glenn, L.C.Glenn, L.C.Real Diamonds in Arkansaw 1910Nashville American., MAY 7TH.United States, Gulf Coast, ArkansasNews Item
DS1910-0283
1912
Glenn, L.C.Glenn, L.C.The Arkansaw Diamond Bearing Peridotite AreaScience., Vol. 35, P. 312. ALSO: NEUES JAHRB. 1914 BD. Feb. 23., P. 22United States, Gulf Coast, Arkansas, PennsylvaniaGeology
DS1910-0284
1912
Glenn, L.C.Glenn, L.C.Arkansaw Diamond Bearing Peridotite AreaGeological Society of America (GSA), Vol. 23, P. 726. (abstract.).United States, Gulf Coast, Arkansas, PennsylvaniaPrairie Creek, Petrology
DS2003-0473
2003
Glennemann, S.Glennemann, S., Kusaja, K., Harris, J.W.Oriented graphite single crystal inclusions in diamondZeitschrift fur Kristallographe, GlobalBlank
DS200412-0675
2003
Glennemann, S.Glennemann, S., Kusaja, K., Harris, J.W.Oriented graphite single crystal inclusions in diamond.Zeitschrift fur Kristallographie, Vol.218, 11, pp. 733-TechnologyDiamond - morphology, inclusions
DS201606-1080
2016
Glennerster, R.Casey, K., Glennerster, R.Reconciliation in Sierra Leone. Conflicts, civil war.Science, Vol. 352, 6287, May 13, pp. 766-767.Africa, Sierra LeoneHistory

Abstract: Since the end of World War II, there have been 259 armed conflicts in 159 locations (1). Sierra Leone's civil war began 25 years ago, at a time when roughly 25% of all countries worldwide were experiencing civil war (2). How can individuals and groups recover from such violent conflicts? On page 787 of this issue, Cilliers et al. (3) provide rigorous evidence on the efficacy of one postwar reconciliation strategy that was implemented in 100 communities in Sierra Leone (4).
DS202002-0213
2020
Glennie, C.L.Okyay, U., Telling, J., Glennie, C.L., Dietrich, W.E.Airborne lidar change detection: an overview of Earth science applications. ( not specific to diamonds)Earth Science Reviews, Vol. 198, 25p. PdfGlobalLidar

Abstract: In the last two decades, airborne laser scanning (ALS) has found widespread application and driven fundamental advances in the Earth sciences. With increasing availability and accessibility, multi-temporal ALS data have been used to advance key research topics related to dynamic Earth surface processes. This review presents a comprehensive compilation of existing applications of ALS change detection to the Earth sciences. We cover a wide scope of material pertinent to the broad field of Earth sciences to encourage the cross-pollination between sub-disciplines and discuss the outlook of ALS change detection for advancing scientific discovery. While significant progress has been made in applying repeat ALS data to change detection, numerous approaches make fundamental assumptions that limit the full potential of repeat ALS data. The use of such data for 3D change detection is, therefore, in need of novel, scalable, and computationally efficient processing algorithms that transcend the ever-increasing data density and spatial coverage. Quantification of uncertainty in change detection results also requires further attention, as it is vitally important to understand what 3D differences detected between epochs represent actual change as opposed to limitations in data or methodology. Although ALS has become increasingly integral to change detection across the Earth sciences, the existence of pre- and post-event ALS data is still uncommon for many isolated hazard events, such as earthquakes, volcanic eruptions, wildfires, and landslides. Consequently, data availability is still a major limitation for many ALS change detection applications.
DS1860-0365
1881
Glenville, T.B.Glenville, T.B.Griqualand West: the Diamond Fields. Guide to South AfricaLondon:, UNKNOWN.Africa, South AfricaTravelogue
DS1981-0182
1981
Glevasskiy, E.B.Glevasskiy, E.B., Kridvik, S.G.Precambrian Carbonatite Complex of the Azov Region. (russian)Izd. Nauk Dumka Kiev Ukrainian SSR, (Russian), 228pRussiaCarbonatite
DS1981-0183
1981
Glevasskiy, YE.B.Glevasskiy, YE.B., Krivdik, S.G.Metallogenesis of the Chernigov Massive Carbonatite, Azov Region.Izd. Nauk Dumka, Kiev, PP. 72-76.RussiaDating
DS200512-0595
2005
Glevassky, Y.B.Kvasnytsya, V.M., Glevassky, Y.B., Kryvdik, S.G.Paleotectonic, petrological and mineralogical criteria of diamond bearing ability of the Ukrainian shield.Gems & Gemology, abstracts Mineralogical Journal (Ukraine) Vol. 26, 1, pp. 24-40. *** in English, Vol. 41, 2, Summer p. 194. abstract onlyEurope, UkraineTectonics
DS1982-0222
1982
Glick, E.E.Glick, E.E., Russ, D.P.Geology and Geophysics of the Ouachita Foreland and Mississippi Embayment.Geological Society of America (GSA), Vol. 14, No. 7, P. 497. (abstract.).GlobalMid-continent, Geophysics
DS1990-1015
1990
Glick, E.E.McKeown, F.A., Hamilton, R.M., Diehl, S.F., Glick, E.E.Diapiric origin of the Blytheville and Pascola arches in the Reelfoot @east-central United States: relation to New Madrid seismicityGeology, Vol. 18, No. 11, November pp. 1158-1162Arkansas, Tennessee, KentuckyReelfoot Rift, Midcontinent
DS1991-1051
1991
Gliko, A.Mareschal, J.C., Gliko, A.Lithospheric thinning uplift, and heat flow preceding riftingTectonophysics, Vol. 197, No. 2-4, November pp. 117-126MantleGeodynamics, Rift system, heat flow
DS201312-0316
2013
Glikson, A.Glikson, A.The asteroid impact connection to planetary evolution: with special reference to large Precambrian and Australian impacts.Springer, 149p. Available Amazon approx $ 50.00AustraliaMeteorite
DS201312-0317
2013
Glikson, A.Glikson, A., Uysal, I.T.Geophysical and structural criteria for the identification of buried impact structures, with reference to Australia.Earth Science Reviews, Vol. 125, pp. 114-122.AustraliaTomography
DS201802-0239
2018
Glikson, A.Glikson, A.Structure and origin of Australian ring and dome features with reference to the search for asteroid impact events.Tectonophysics, Vol. 722, pp. 175-196.Australiaring structures

Abstract: Ring, dome and crater features on the Australian continent and shelf include (A) 38 structures of confirmed or probable asteroid and meteorite impact origin and (B) numerous buried and exposed ring, dome and crater features of undefined origin. A large number of the latter include structural and geophysical elements consistent with impact structures, pending test by field investigations and/or drilling. This paper documents and briefly describes 43 ring and dome features with the aim of appraising their similarities and differences from those of impact structures. Discrimination between impact structures and igneous plugs, volcanic caldera and salt domes require field work and/or drilling. Where crater-like morphological patterns intersect pre-existing linear structural features and contain central morphological highs and unique thrust and fault patterns an impact connection needs to tested in the field. Hints of potential buried impact structures may be furnished by single or multi-ring TMI patterns, circular TMI quiet zones, corresponding gravity patterns, low velocity and non-reflective seismic zones. A) Examples of crater-form and dome-form features containing elements consistent with an impact origin, though unproven, include Auvergne, Delamere, Fiery Creek, Monte Christo, Mount Moffatt, Tanami East, Youngerina, and Tingha. B) Examples of buried multi-ring features of possible to probable impact origin include Augathella, Balfour Downs, Calvert Hills, Camooweal, Green Swamp Well, Herbert, Ikybon River, Ilkurka, Lennis, McLarty Hills, Mount Davies, Mulkara; Neale; Sheridan Creek, Oodjuongari and Renehan. C) Examples of igneous plugs unrelated to impacts include the Monto gabbro and numerous circular granitoid plugs such as Windinie Hills granite and Yataga granodiorite. D) Large circular structures such as Mount Ashmore and Gnargoo are considered to have convincing structural deformation features warranting classification as probable impact structures. The origin of very large circular TMI and gravity patterns such as of the Diamantina River drainage feature, Coonamona anomaly and the multiple TMI ring pattern of the Deniliquin-Booligal remain unresolved. The advent of ~ 40 m TMI grid coverage promises to further uncover ring and dome features, such as the McLarty Hills multi-ring feature, potentially increasing the inventory of ring structures on the Australian continent. Compared with frequency distribution patterns of extra-terrestrial impact structures worldwide, the Australian record displays a relatively common occurrence of large impact structures and relative depletion in small impact structures and craters. This is explained by the better preservation of large structures at deep crustal zones as compared to the erosion of small craters.
DS1991-1674
1991
Glikson, A.V.Sun, S.S., Wallace, D.A., Hoatson, D.M., Glikson, A.V.Use of geochemistry as a guide to platinum group element potential of mafic ultramafic rocks- examples the West Pilbara block and Halls Creek Mobile Zone:Precambrian Research, Vol. 50, No. 102, April pp. 1-35AustraliaPlatinuM., Geochemistry - review
DS1991-0582
1991
Glikson, A.Y.Glikson, A.Y., Stewart, A.J., Ballhaus, C.G.Layered basic/ultrabasic intrusions and the deep seated Proterozoic crust of central AustraliaGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 60AustraliaTectonics, Ultrabasic
DS1992-0581
1992
Glikson, A.Y.Glikson, A.Y., Stewart, A.J.Mapping in high grade terranes: use of remotely sensed dat a and airbornegeophysicsB.m.r. Research Newsletter, No. 16, April pp. 22-23AustraliaGeophysics, High grade terranes
DS1993-0552
1993
Glikson, A.Y.Glikson, A.Y.Asteroids and early Precambrian crustal evolutionEarth Science Reviews, Vol. 35, No. 3, October pp. 285-320MantleAsteroids, Crustal evolution
DS1995-0641
1995
Glikson, A.Y.Glikson, A.Y.Asteroid/comet mega-impacts may have triggered major episodes of crustalevolution.Eos, Vol. 76, No. 6, Feb. 7, p. 54, 55, 56.GlobalImpact structures, Tectonics
DS1997-0421
1997
Glikson, A.Y.Glikson, A.Y.Mineral mapping in the North Pilbara CratonAgso Research Newsletter, No. 26, May pp. 1-4AustraliaThematic Mapper multispectral mapping
DS1999-0254
1999
Glikson, A.Y.Glikson, A.Y.Oceanic mega impacts and crustal evolutionGeology, Vol. 27, No. 5, May pp. 387-90.GlobalCraters, impacts, Gondwana, East African Rift
DS2002-0603
2002
Glikson, A.Y.Gorter, J.D., Glikson, A.Y.Fohn lamproite and a possible late Eocene pre- Miocene diatreme field, Northern Bonaparte Basin, Timor Sea.Australian Journal of Earth Sciences, Vol. 49, 5, pp. 847-68.Australia, Timor SeaGeophysics - seismics, Lamproite, diatreme
DS200612-0471
2005
Glikson, A.Y.Glikson, A.Y.Geochemical and isotopic signatures of Archean to Paleoproterozoic extraterrestrial impact ejecta/fallout units.Australian Journal of Earth Sciences, Vol. 52, 4-5, pp. 785-798.GlobalGeochemistry - meteorites
DS200812-0417
2008
Glikson, A.Y.Glikson, A.Y.Field evidence of eros-scale asteroids and impact forcing of Precambrian geodynamic episodes: Kaapvaal (South Africa) and Pilbara ( western Australia) cratonsEarth and Planetary Science Letters, Vol. 267, 3-4, pp. 559-570.Africa, South Africa, AustraliaCraton
DS201112-0374
2011
Glikson, A.Y.Glikson, A.Y., Vickers, J.Asteroid impact connections of crustal evolution.Australian Journal of Earth Sciences, Vol.57, 1, pp. 79-95.MantleImpacts
DS201412-0298
2014
Glikson, A.Y.Glikson, A.Y.The Archean: geological and geochemical windows into the Early Earth.Springer, 238p. Approx $ 129.00 also ebook springer.com/shopGlobalEvolution of continents, Early Earth features, volcanism
DS1989-0518
1989
GLIMPCE Seismic Reflection GroupGLIMPCE Seismic Reflection GroupLong-Offset recordingsEos, Vol. 70, No. 38, September 19, pp. 841, 852-853Michigan, Ontario, WisconsinTectonics, Geophysics
DS2003-0474
2003
Glinnemann, J.Glinnemann, J., Kusaka, K., Harris, J., Bleisteiner, B., Winkler, B.Oriented graphite single crystal inclusions in diamond8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractNorthwest TerritoriesDiamonds - inclusions, Deposit - Panda
DS200412-0676
2004
Glinnemann, J.Glinnemann, J., Burghammer, M., Winkler, B., Nasdala, L., Harris, J.W.Single crystal graphite inclusions in natural diamonds.Lithos, ABSTRACTS only, Vol. 73, p. S44. abstractCanada, Northwest TerritoriesDiamond morphology, Panda, Ekati
DS200412-1406
2003
Glinnemann, J.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
DS200512-0768
2005
Glinnemann, J.Nasdala, L., Hofmeister, W., Harris, J.W., Glinnemann, J.Growth zoning and strain patterns inside diamond crystals as revealed by Raman maps.American Mineralogist, Vol. 90, pp. 745-748.Canada, Northwest TerritoriesRaman mapping technology - Panda, Ekati
DS201212-0248
2012
Glisovic, P.Glisovic, P., Forte, A.M., Moucha, R.Time dependent convection models of mantle thermal structure constrained by seismic tomography and geodynamics: implications for mantle plume dynamics and CMB heat flow.Geophysical Journal International, Vol. 190, 2, pp. 785-815.MantleGeothermometry
DS201012-0157
2010
Gloaguen, E.Dimitrakopoulos, R., Mustapha, H., Gloaguen, E.High order statistics of spatial random fields: exploring spatial cumulants for modeling complex non-gaussian and non-linear phenomena.Mathematical Geosciences, Vol. 42, 1., pp. 65-99.Canada, Northwest TerritoriesDeposit - Ekati
DS201904-0723
2017
Gloaguen, E.Cate, A., Perozzi, L., Gloaguen, E., Blouin, M.Machine learning as a tool for geologists. Not specific to diamondsThe leading Edge, https://dx.doi.org/10.1190/tle36030064.1Globaldata sets

Abstract: Machine learning is becoming an appealing tool in various fields of earth sciences, especially in resources estimation. Six machine learning algorithms have been used to predict the presence of gold mineralization in drill core from geophysical logs acquired at the Lalor deposit, Manitoba, Canada. Results show that the integration of a set of rock physical properties — measured at closely spaced intervals along the drill core — with ensemble machine learning algorithms allows the detection of gold-bearing intervals with an adequate rate of success. Since the resulting prediction is continuous along the drill core, the use of this type of tool in the future will help geologists in selecting sound intervals for assay sampling and in modeling more continuous ore bodies during the entire life of a mine.
DS1991-1079
1991
Gloan, P.Maurin, J.C., Boudzoumou, F., Djama, L.M., Gloan, P., Michard, A.The Proterozoic West Congolian belt and its foreland in Congo-newComptes Rendu Academy of Science Ser. II, Mec. Phys., (in French), Vol. 312, No. 11, pp. 1327-1334Central AfricaProterozoic, Geochronology
DS2000-0342
2000
Global Diamond CouncilGlobal Diamond CouncilWorld diamond council praises passage of U.N. measure to fight conflict diamonds.World Diamond Council, Dec. 6, 1p.Sierra Leone, Angola, Democratic Republic of CongoNews item, Conflict diamonds
DS1990-0580
1990
Global Geoscience transectsGlobal Geoscience transectsGlobal geoscience transectsA.g.u, Syria, China, Tibet, Brazil, Australia, Andes, Chile, ArgentinaGeophysics, Remote sensing
DS1991-0583
1991
Global Tectonics and MetallogenyGlobal Tectonics and MetallogenyThe role of the upper mantle in metallogenyGlobal Tectonics and Metallogeny, Vol. 4, No. 1, 2, September pp. 1-84. Some lisited sepeGlobalGlobal Tectonics and Metallogeny, Metallogeny
DS1996-0536
1996
Global Tectonics and MetallogenyGlobal Tectonics and MetallogenyProgress report of laboratory of global tectonics and metallogeny inPrague... abstracts of active projectsGlobal Tectonics and Metallogeny, Vol. 6, No. 1, pp. 57-72EuropeMetallogeny projects
DS1997-0422
1997
Global Tectonics and MetallogenyGlobal Tectonics and MetallogenyThe relationships between metal concentration and deep structures of thelithosphereGlobal Tectonics and Metallogeny, Vol. 6, No. 2, March pp. 75-160Australia, China, United States, Russia, Siberia, Venezuela MantleCraton, tectonics, MOHO, Gold
DS2000-0343
2000
Global WitnessGlobal WitnessConflict diamonds. Possibilities for the identification, certification and control of diamonds.Global Witness briefing document, June, 41p.Angola, Sierra Leone, Liberia, GlobalDiamond industry - overview, technology, legal
DS2001-0388
2001
Globe & MailGlobe & MailRio Tinto PLC profit jump surprises market... 18% jumpRio Tinto Plc., Feb. 6, 1/2p.AustraliaNews item - press release, Rio Tinto
DS201212-0249
2012
Globe & MailGlobe & MailChasing Manor's millions… mystery of the diamonds Boaz Manor bought with investors' money?Report on Business, November pp. 51-58.GlobalMissing diamonds
DS1860-0614
1889
Globe DemocratGlobe DemocratCalifornia Diamonds. an Australian Diamond Hunter Beginning to Work in Amador.Globe Democrat., Jan. 5TH.United States, California, West CoastDiamond Occurrence
DS1860-0128
1871
GlobusGlobusDie Diamanten felder in Suedafrika ( Orange and Vaal rivers)Globus (braunschweig), Vol. 18, 1870-1871, PP. 369-372.Africa, South Africa, Cape ProvinceHistory
DS2002-0582
2002
Gloday, J.Gloday, J., Bingen, B., Austrheim, Molina, RusinPrecise eclogitization ages deduced from Rb Sr mineral systematics: the Maksyutov complex, southern Urals.Geochimica et Cosmochimica Acta, Vol. 66,7,pp. 1221-35.Russia, southern UralsSubduction related high pressure metamorphism
DS2000-0543
2000
Glodny, J.Kuhn, A., Glodny, J., Iden, K., Austrheim, H.Retention of Precambrian Rubidium-Strontium phlogopite ages through Caledonian eclogite facies metamorphism, Bergen ArcLithos, Vol. 51, No. 4, June pp. 305-30.Norway, WesternEclogite, metamorphism
DS2002-1073
2002
Glodny, J.Molina, J.F., Austrheim, H., Glodny, J., Rusin, A.The eclogites of the Marun Keu complex: fluid control on reaction kinetics and metasomatism during high P metamorphismLithos, Vol.61, 1-2, March, pp. 55-78.Russia, Polar UralsMetamorphism - metasomatism, Eclogites
DS2002-1074
2002
Glodny, J.Molina, J.F., Austrheim, H., Glodny, J., Rusin, A.The eclogites of the Marun-Keu complex, Polar Urals: fluid control on reaction kinetics and metasomatism UHPLithos, Vol. 61, No.1-2,pp. 55-78.Russia, UralsEclogites, Metamorphism - high P
DS2003-0475
2003
Glodny, J.Glodny, J., Austrheim, H., Mlina, J.F., Rusin, A.J., Seward, D.Rb Sr record of fluid rock interaction in eclogites: the Marun-Keu complex, PolarGeochimica et Cosmochimica Acta, Vol. 67, 22, pp. 4353-4371.Russia, UralsGeochronology, eclogites
DS200412-0677
2003
Glodny, J.Glodny, J., Austrheim, H., Mlina, J.F., Rusin, A.J., Seward, D.Rb Sr record of fluid rock interaction in eclogites: the Marun-Keu complex, Polar Urals, Russia.Geochimica et Cosmochimica Acta, Vol. 67, 22, pp. 4353-4371.Russia, UralsGeochronology, eclogites
DS200412-1350
2004
Glodny, J.Molina, J.F., Poli, S., Austrheim, J., Glodny, J., Rusin, A.Eclogite facies vein systems in the Marun-Keu complex ( Polar Urals, Russia): textural, chemical, thermal constraints for patterContributions to Mineralogy and Petrology, Vol. 147, 4, pp. 484-504.Russia, UralsEclogite
DS201412-0001
2014
Glodny, J.Abdelfadil, K.M., Romer, R.L., Glodny, J.Mantle wedge metasomatism revealed by Li isotopes in orogenic lamprophyres. ( Bohemian Massif)Lithos, Vol. 196-197, pp. 14-26.EuropeLamprophyre
DS201609-1727
2016
Glodny, J.Krmicek, L., Romer, R.L.,Ulrych, J., Glodny, J., Prelevic, D.Petrogenesis of orogenic lamproites of the Bohemian Massif: Sr-Nd-Pb-Li isotope constraints for Variscan enrichment of ultra-depleted mantle domains.Gondwana Research, Vol. 35, pp. 198-216.EuropeLamproite

Abstract: During convergence of Gondwana-derived microplates and Laurussia in the Palaeozoic, subduction of oceanic and continental crusts and their sedimentary cover introduced material of regionally contrasting chemical and isotopic compositions into the mantle. This slab material metasomatised the local mantle, producing a highly heterogeneous lithospheric mantle beneath the European Variscides. The eastern termination of the European Variscides (Moldanubian and Saxo-Thuringian zones of Austria, Czech Republic, Germany and Poland) is unusual in that the mantle was modified by material from several subduction zones within a small area. Orogenic lamproites sampled this lithospheric mantle, which has a chemical signature reflecting extreme depletion (low CaO and Al2O3 contents and high Mg-number) followed by strong metasomatic enrichment, giving rise to crust-like trace element patterns, variable radiogenic 87Sr/86Sr(330) (0.7062-0.7127) and non-radiogenic Nd isotopic compositions (?Nd(330) = ? 2.8 to ? 7.8), crustal Pb isotopic compositions, and a wide range of ?7Li values (? 5.1 to + 5.1). This metasomatic signature is variably expressed in the lamproites, depending on the extent of melting and the nature of the source of the metasomatic component. Preferential melting of the metasomatically enriched (veined) lithospheric mantle with K-rich amphibole resulted in lamproitic melts with very negative, crust-like ?7Li values, which correlate positively with peralkalinity, HFSE contents and lower ?Nd. Both the higher degree of melting and progressive consumption of the metasomatic component reduce the chemical and isotopic imprints of the metasomatic end member. The very positive ?7Li values of some lamproites indicate that the source of these lamproites may have been modified by subducted oceanic lithosphere. Fresh olivine from the Brloh (Moldanubian) lamproitic dyke shows very high Fo (up to 94%) and very high Li contents (up to 25 ppm), demonstrating that the extremely depleted and later enriched lithospheric mantle may have contributed significantly to the Li budget of the lamproites. The regional distribution of lamproites with contrasting chemical and isotopic fingerprints mimics the distribution of the different Variscan subduction zones.
DS201911-2572
2019
Glodny, J.Wang, D., Romer, R.L., Guo, J-h., Glodny, J.Li and B isotopic fingerprint of Archean subduction.Geochimica et Cosmochimica Acta, in press available. 45p.Mantlesubduction

Abstract: Archean peridotite xenoliths in the ?2.52 Ga Zhulagou diorite (Yinshan Block, North China Craton) show chemical and Li isotopic evidence for metasomatism above an ancient subduction zone. The peridotite xenoliths are composed of olivine + orthopyroxene + amphibole + phlogopite + serpentine. The peridotite xenoliths have low whole-rock Mg# (80-81) and low Mg# (81-84) in olivine, indicating that they are cumulates that formed near the crust-mantle boundary. Petrological observations, mineral trace element data and isotopic ages show that the sequence of hydrous minerals is amphibole-serpentine-phlogopite. SIMS U-Pb dating of zircon from peridotites yielded an upper intercept age at ?2.53 Ga, and a U-Pb lower intercept age at ?1.8 Ga. The age of ?2.53 Ga is interpreted to date the crystallization of zircon from the metasomatized mantle melt that formed the Zhulagou cumulate peridotite. Rb-Sr mineral isochrons date phlogopite formation at ?1760 Ma, consistent with the lower intercept age of zircon. Pargasitic amphibole from the Zhulagou peridotites has fractionated REE, pronounced depletions of Nb, Ta, Zr and Ti, and heavy ?7Li (?+14‰) and light ?11B (?-11‰). Combined with slightly depleted mantle whole rock ?Nd (?+1.3) and high zircon ?18O (+5.6 to +7.0‰), the amphibole composition reflects that the peridotite xenoliths formed from melts that carried the geochemical and isotopic fingerprint typical for a metasomatized mantle wedge above a subduction zone. The Zhulagou peridotite xenoliths have the highest ?7Li values (?+12‰) recorded in Archean peridotites. Isotopically heavy Li and light B in olivine, orthopyroxene, and amphibole from the peridotite xenoliths show that Li and B may decouple during partial melting or fluid release from the subducted slab. The decoupling of Li and B may have a variety of reasons, including different host minerals for Li and B in the source and different protoliths in the subducted slab. The Li and B isotopic record on the recycling of ancient material demonstrates that modern-style subduction operated already in the late Archean.
DS202001-0046
2019
Glodny, J.Wang, D., Romer, R.L., Guo, J-h., Glodny, J.Li and B isotopic fingerprint of Archean subduction.Geochimica et Cosmochimica Acta, in press available pdf 45p.Chinacraton

Abstract: Archean peridotite xenoliths in the ?2.52?Ga Zhulagou diorite (Yinshan Block, North China Craton) show chemical and Li isotopic evidence for metasomatism above an ancient subduction zone. The peridotite xenoliths are composed of olivine?+?orthopyroxene?+?amphibole?+?phlogopite?+?serpentine. The peridotite xenoliths have low whole-rock Mg# (80-81) and low Mg# (81-84) in olivine, indicating that they are cumulates that formed near the crust-mantle boundary. Petrological observations, mineral trace element data and isotopic ages show that the sequence of hydrous minerals is amphibole-serpentine-phlogopite. SIMS U-Pb dating of zircon from peridotites yielded an upper intercept age at ?2.53?Ga, and a U-Pb lower intercept age at ?1.8?Ga. The age of ?2.53?Ga is interpreted to date the crystallization of zircon from the metasomatized mantle melt that formed the Zhulagou cumulate peridotite. Rb-Sr mineral isochrons date phlogopite formation at ?1760?Ma, consistent with the lower intercept age of zircon. Pargasitic amphibole from the Zhulagou peridotites has fractionated REE, pronounced depletions of Nb, Ta, Zr and Ti, and heavy ?7Li (?+14‰) and light ?11B (?-11‰). Combined with slightly depleted mantle whole rock ?Nd (?+1.3) and high zircon ?18O (+5.6 to +7.0‰), the amphibole composition reflects that the peridotite xenoliths formed from melts that carried the geochemical and isotopic fingerprint typical for a metasomatized mantle wedge above a subduction zone. The Zhulagou peridotite xenoliths have the highest ?7Li values (?+12‰) recorded in Archean peridotites. Isotopically heavy Li and light B in olivine, orthopyroxene, and amphibole from the peridotite xenoliths show that Li and B may decouple during partial melting or fluid release from the subducted slab. The decoupling of Li and B may have a variety of reasons, including different host minerals for Li and B in the source and different protoliths in the subducted slab. The Li and B isotopic record on the recycling of ancient material demonstrates that modern-style subduction operated already in the late Archean.
DS202009-1637
2020
Glodny, J.Krmicek, L., Romer, R.L., Cempirek, J., Gadas, P., Krmickova, S., Glodny, J.Petrographic and Sr-Nd-Pb-Li isotope characteristics of a complex lamproite intrusion from the Saxo-Thuringian zone: a unique example of peralkaline mantle-derived melt differentiation.Lithos, Vol. 374-375, 15p. PdfEurope, Bohemian Massiflamproites

Abstract: Variscan orogenic lamproites in the Bohemian Massif predominantly occur as 1 to 2?m wide and petrographically uniform dykes along the eastern borders of the Moldanubian and Saxo-Thuringian zones. Variscan orogenic lamproites were derived by preferential melting of subduction-related olivine-free metasomatic vein assemblages stabilised in the lithospheric mantle. These lamproitic melts may subsequently undergo extensive differentiation. In this study, we present the first combined petrographic and Sr-Nd-Pb-Li isotope characteristics of a complex lamproite exposed at ca 100?m long profile near Horní Rokytnice (Czech Republic) in the Saxo-Thuringian Zone. This lamproite is characterised by the primary mineral assemblage of K-amphibole + K-feldspar ± aegirine and quartz that petrographically varies from relatively primitive (fine-grained, mafic) to more differentiated (medium- to coarse-grained, felsic) pegmatitic lamproite domains. These domains may represent the product of crystallisation of immiscible liquids that had separated from the mafic melt. The primitive lamproite zone is characterised by the typomorphic minerals - baotite, benitoite, and henrymeyerite. The more differentiated pegmatitic domains are free of aegirine and show replacement of primary red-luminescent (Fe3+-rich) K-feldspar by blue-luminescent (Fe-poor) K-feldspar. Residual fluids rich in Ca, Ti, and HFSE in combination with the decreasing peralkalinity of the lamproite system resulted in the local formation of secondary zircon, titanite and quartz at the expense of the primary Ti-Ba-Zr-K lamproitic mineral assemblages. Lamproites from the Moldanubian and Saxo-Thuringian zones fall on separate mixing trends in the 87Sr/86Sr(t) - ?Nd(t) diagram, which indicates that the mantle beneath these two zones had been metasomatised by different crustal material. The scatter in the peralkalinity index vs. ?7Li diagram indicates that the Li isotope composition is not controlled by mixing of two end members metasome and ambient depleted mantle alone, but may also be affected by late-stage magmatic and hydrothermal processes. The compositionally zoned Horní Rokytnice dyke is special as the petrographically different types show a variation of about 4 ?-units in ?7Li due to dyke-internal processes, such as fractionation, which increases ?7Li in late-stage lamproitic melts, and post-emplacement interaction with fluids that reduced ?7Li in samples that have lost Li. Post-emplacement alteration also led to the disturbance in the Pb isotope systematics of the differentiated orogenic lamproite as indicated by variable over-correction of in situ radiogenic Pb ingrowth.
DS202101-0021
2020
Glodny, J.Krmicek, L., Romer, R.L., Timmerman, M.J., Ultych, J., Glodny, J.Long lasting ( 65Ma) regionally contrasting Late-to Post-orogenic variscan mantle-derived potassic magmatism in the Bohemian Massif.Journal of Petrology, Vol. 61, 7, doi.org/10.1093 /petrology/egaa072Europemagmatism

Abstract: The orogenic development after the continental collision between Laurussia and Gondwana, led to two contrasting associations of mantle-derived magmatic rocks on the territory of the Bohemian Massif: (i) a 340-310?Ma lamprophyre-lamproite orogenic association; and (ii) a 300-275?Ma lamprophyre association of anorogenic affinity. Major types of potassic mantle-derived magmatic rocks recognized in the orogenic and anorogenic associations include: (i) calc-alkaline to alkaline lamprophyres; (ii) alkaline ‘orthopyroxene minettes’ and geochemically related rocks grouped here under the new term lampyrite; and (iii) peralkaline lamproites. These three types significantly differ with respect to mineral, whole-rock and Sr-Nd-Pb-Li isotope composition and spatial distribution. The calc-alkaline lamprophyres occur throughout the entire Saxo-Thuringian and Moldanubian zones, whereas the different types of malte-derived potassic rocks are spatially restricted to particular zones. Rocks of the Carboniferous lamprophyre-lamproite orogenic association are characterized by variable negative ?Nd(i) and variably radiogenic Sr(i), whereas the rocks of the Permian lamprophyre association of anorogenic affinity are characterized by positive ?Nd(i) and relatively young depleted-mantle Nd-model ages reflecting increasing input from upwelling asthenospheric mantle. The small variation in the Pb isotopic composition of post-collisional potassic mantle-derived magmatic rocks (of both the orogenic and anorogenic series) implies that the Pb budget of the mantle beneath the Bohemian Massif is dominated by the same crust-derived material, which itself may include material derived from several sources. The source rocks of ‘orthopyroxene minettes’ are characterized by isotopically light (‘eclogitic’) Li and strongly radiogenic (crustal) Sr and may have been metasomatized by high-pressure fluids along the edge of a subduction zone. In contrast, the strongly Al2O3 and CaO depleted mantle source of the lamproites is characterized by isotopically heavy Li and high SiO2 and extreme K2O contents. This mantle source may have been metasomatized predominantly by melts. The mantle source of the lamprophyres may have undergone metasomatism by both fluids and melts.
DS201012-0782
2010
Gloria da Silva, M.Teixeira, J.B.G., Gloria da Silva, M., Misi, A., Cerqueira Pereira Cruz, S., Haroldo da Silva Sa, J.Geotectonic setting and metallogeny of the northern Sao Francisco Craton, Bahia, Brazil.Journal of South American Earth Sciences, Vol. 30, 2, pp. 71-83.South America, BrazilTectonics
DS201412-0299
2014
Glorie, S.Glorie, S., Zhimulev, F.I., Buslov, M.M., Andersen, T., Plavsa, D., Izmer, A., Vanhaecke, F., De Grave, J.Formation of the Kokchetav subduction collision zone - northern Kazakhstan : insights from zircon U-Pb and Lu-Hf isotope systematics.Gondwana Research, Vol. 27, pp. 424-438.Russia, KazakhstanSubduction
DS201908-1769
2019
Glorie, S.Alessio, B.L., Glorie, S., Collins, A.S., Jourdan, F., Jepson, G., Nixon, A., Siegfried, P.R., Clark, C.The thermo-tectonic evolution of the southern Congo craton margin as determined from apatite and muscovite thermochronology.Tectonophysics, Vol. 766, pp. 398-415.Africa, Zambia, Malawi, Mozambique, Tanzaniacraton

Abstract: The Southern Irumide Belt (SIB) of Zambia consists of predominantly Mesoproterozoic terranes that record a pervasive tectono-metamorphic overprint from collision between the Congo and Kalahari cratons in the final stages of Gondwana amalgamation. This study applies multi-method thermochronology to samples throughout southern Zambia to constrain the post-collisional, Phanerozoic thermo-tectonic evolution of the region. U-Pb apatite and 40Ar/39Ar muscovite data are used to constrain the cooling history of the region following Congo-Kalahari collision, and reveal ages of c. 550-450?Ma. Variations in the recorded cooling ages are interpreted to relate to localised post-tectonic magmatism and the proximity of analysed samples to the Congo-Kalahari suture. Apatite fission track data are used to constrain the low-temperature thermo-tectonic evolution of the region and identify mean central ages of c. 320-300, 210-200 and 120-110?Ma. Thermal modelling of these samples identifies a number of thermal events occurring in the region throughout the Phanerozoic. Carboniferous to Permian-Triassic heating is suggested to relate to the development of Karoo rift basins found throughout central Africa and constrain the timing of sedimentation in the basin. Permian to Jurassic cooling is identified in a number of samples, reflecting exhumation as a result of the Mauritanian-Variscan and Gondwanide orogenies. Subsequent cooling of the majority of samples occurs from the Cretaceous and persists until present, reflecting exhumation in response to larger scale rifting associated with the break-up of Gondwana. Each model reveals a later phase of enhanced cooling beginning at c. 30?Ma that, if not an artefact of modelling, corresponds to the development of the East African Rift System. The obtained thermochronological data elucidate the previously unconstrained thermal evolution of the SIB, and provides a refined regional framework for constraining the tectonic history of central Africa throughout the Phanerozoic.
DS1980-0144
1980
Glover, J.E.Glover, J.E., Groves, D.I.Kimberlites and Diamonds: a Seminar Organized by the Department Of Geology.Perth: West. Aust. University Geol. Department Extension Service., No. 5, 129P.AustraliaKimberlite, Kimberley, Janlib
DS1992-0582
1992
Glover, J.E.Glover, J.E., Ho, S.E.The Archean: terrains, processes and metallogenyUniversity of Western Australia, o. 22, $ 79.00Australia, Russia, Canada, Quebec, northwest Territories, South AfricaArchean, terrains, processes, metallogeny, Gold deposits
DS1992-1204
1992
Glover, L.Ping Wang, Glover, L.A tectonics test of the most commonly used geochemical discriminant diagrams and patterns.Earth Science Reviews, Vol. 33, pp. 111-31.GlobalBasalts, Tectonic settings
DS1994-1821
1994
Glover, L.Valentino, D.W., Gates, A.E., Glover, L.Late Paleozoic transcurrent tectonic assembly of the central AppalachianpiedmontTectonics, Vol. 13, No. 1, February, pp. 110-126AppalachiaTectonics
DS1997-0423
1997
Glover, L.Glover, L., Gates, A.E.Central and southern Appalachians suturesGeological Society of America Special Paper, No. 314, $ 50.00Appalachia, MidcontinentBook - ad, Tectonics
DS1994-0629
1994
Glover, P.W.J.Glover, P.W.J.Electrical conductivity of the continental crustGeophysical Research Letters, Vol. 21, No. 22, Nov. 1, pp. 2357-2360.Mantle, Italy, NorwayGeophysics, Graphite
DS1995-0642
1995
Glover, P.W.J.Glover, P.W.J., Vine, F.J.Beyond KTB -electrical conductivity of the deep continental crustSurveys in Geophysics, Vol. 16, pp. 5-36MantleGeophysics -seismics, Conductivity
DS1995-0643
1995
Glover, P.W.J.Glover, P.W.J., Vine, F.J.Beyond KTB -electrical conductivity of the deep continental crustSurveys in Geophysics, Vol. 16, pp. 5-36.Mantle, crustGeophysics, Magneto -telluric (MT) methods
DS1987-0251
1987
Glowka, D.A.Glowka, D.A.Development of a method for predicting the performance and wear of PDC(Polycrystalline diamond compact) drill bitsNational Technical Information Service/Sandia Lab., DE88001450, 197p. $ 19.95 United States, GlobalBlank
DS200512-0346
2005
GluckaufGluckaufExploration for diamonds with large borehole drilling technology.Gluckauf, Vol. 141, 1, pp. 43-48. Ingenta 1050878735Drilling techniques
DS2000-0600
2000
Glukhov, Y.V.Lyutoev, V.P., Glukhov, Y.V., Isaenko, S.I.Epigene nitrogen defects and metallic films on the surface of diamonds from the middle Timan region.Doklady Academy of Sciences, Vol. 375, No. 8, Oct. Nov. pp. 1251-54.Russia, TimanDiamond - morphology
DS1998-0517
1998
Glukhovski, M.Z.Glukhovski, M.Z., Moralev, V.M.The hot belt of the early earth and present day mantle geodynamics according to seismic tomographic data.Russian Geology and Geophysics, Vol. 39, No. 1, pp. 3-10.RussiaGeodynamics, Geophysics - seismic
DS1994-0630
1994
Glukhovskii, M.Z.Glukhovskii, M.Z., Moralyov, V.M., Zhavoron, V.E.Prospecting of diamond bearing kimberlites in Voronezh crystal massif using satellite images.(Russian)Soviet Journal of Remote, (Russian), Vol. 11, No. 6, pp. 1015-1026. # QA799RussiaRemote sensing, Voronezh
DS2001-0389
2001
Glukhovskii, M.Z.Glukhovskii, M.Z., Moralev, V.M., Borisovskii, S.E.Zirconium and hafnium in zircons from Archean enderbites of Sunnagin dome, evolution of ancient crustDoklady, Vol.381A,No.9, Nov-Dec. pp. 1088-91.Russia, Aldan shieldPetrology
DS2003-0476
2003
Glukhovskii, M.Z.Glukhovskii, M.Z., Moralev, V.M.Archean mafic dyke swarms as the indicators of the specific features of the early Earth'sGeotectonics, Vol. 37, 2, pp. 124-139.RussiaDike swarms
DS200412-0678
2004
Glukhovskii, M.Z.Glukhovskii, M.Z., Bayanova, T.B., Moralev, V.M., Levkovich, N.V.The problem of tectonic evolution of the ancient continental crust: evidence from new U Pb zircon datings of rocks from the SunnDoklady Earth Sciences, Vol. 395, 2, pp. 157-160.Russia, Aldan ShieldTectonics
DS200412-0679
2003
Glukhovskii, M.Z.Glukhovskii, M.Z., Moralev, V.M.Archean mafic dyke swarms as the indicators of the specific features of the early Earth's plume tectonic regime ( with referenceGeotectonics, Vol. 37, 2, pp. 124-139.RussiaDike swarms
DS201312-0318
2013
Glukhovskii, M.Z.Glukhovskii, M.Z., Kuzmin, M.I.The Kotuikan ring structure as possible evidence for a large impact event in the northern Siberian craton.Russian Geology and Geophysics, Vol. 54, 8, pp. 663-673.RussiaAstrobleme
DS1993-0553
1993
Glukhovskiy, M.Z.Glukhovskiy, M.Z., Moralev, V.M.Archean metabasites of the Sunnagin Dome, Aldan Shield: petrochemistry andoriginInternational Geology Review, Vol. 35, No. 8, August pp. 739-757Russia, Commonwealth of Independent States (CIS)Alkaline rocks, Petrochemistry
DS2000-0684
2000
Glukhovsky, M.Z.Moralev, V.M., Glukhovsky, M.Z.Diamond bearing kimberlite fields of the Siberian Craton and the Early Precambrian geodynamics.Ore Geology Review, Vol. 17, pp. 141-53.Russia, SiberiaTectonics - basement, structure, magmatism, seismics, Deposit - Udachnaya, Mir
DS200612-0472
2006
Glukhovsky, M.Z.Glukhovsky, M.Z.Giant swarms of Precambrian mafic dikes and potential diamond resources of ancient platforms.Geotectonics, Vol. 40, 1, Jan. pp. 11-24.Russia, CanadaDike swarms - mantle plumes, UHP, plate tectonics
DS201910-2242
2019
Glushkova, N.V.Afanasiev, V.P., Nikolenko, E.I., Glushkova, N.V., Zolnikov, I.D.The new Massadou diamondiferous kimberlite field in Guinea.Geology of Ore Deposits, Vol. 61, 4, pp. 92-100.Africa, Guineadeposit - Massadou

Abstract: A new Massadou kimberlite field, was discovered in southeastern Guinea, near the town of Macenta. It consists of 16 poorly diamondiferous kimberlite dikes, ~1 m thick on average. The ore-controlling zone has a width of around 600 m, its orientation corresponds to the K-4 trend after S. Haggerty, and it is quite well detectable in satellite images. A thick laterite weathering profile has developed on the kimberlites. The main indicator minerals are pyrope, chromite, and ilmenite. Ilmenite grains have a zoned structure with a high-Fe core (hemoilmenite) overgrown by a parallel-columnar aggregate of Mg-ilmente rim resulting from interaction of the core phase with kimberlitic melt. The age of kimberlites is estimated as 140-145 Ma by analogy with those in adjacent areas. Dikes occur as an independent form of kimberlite magmatism in the Guinean-Liberian shield, rather than being roots of kimberlite pipes; therefore, the erosion cutout is relatively small and large-scale diamond placers should not be expected.
DS202004-0504
2020
Glybin, Y.N.Chernykh, 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.
DS200712-0915
2007
Gnaneshwar RaoRoy, P., Balaram, V., Kumar, A., Satyanarayanan, M., Gnaneshwar Rao, ThotaNew REE and trace element dat a on two kimberlite reference materials by ICP-MS.Geostandards and Geoanalytical Research, Vol. 31, 3, pp. 261-273.TechnologyKimberlte trace elements
DS200912-0649
2007
GnaneshwaraRoy, 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
DS200812-1137
2008
Gnaneshwara Rao, T.Subba Rao, D.V., Sridhar, D.N., Balaram, V., Nagaraju, K., Gnaneshwara Rao, T., Keshavakrishna, A., Singh, U.P.Proterozoic mafic ultramafic dyke swarms in the vicinity of Chhattisgarh Khariar Singhora basins in northern Bastar Craton, central India.Indian Dykes: editors Srivastava, Sivaji, Chalapathi Rao, pp. 377-396.IndiaBoninites
DS200912-0418
2008
Gnclu, M.C.Kurt, M.S., Alpasian, M., Gnclu, M.C., Temel, A.Geochemistry of late stage medium to high K calc alkaline and shoshoninitc dikes in the Ulukla Basin, central Anatolia, Turkey; petrogenesis and tectonicsGeochemistry International, Vol. 46, 11, pp. 1145-1163.Europe, TurkeyShoshonite
DS1960-0148
1961
Gnevushev, M.A.Gnevushev, M.A., Bartoshinsky, Z.V., Zinkov, H.P.Dat a on the Distribution Patterns of Diamonds in the Kimberlite Pipes of Western Yakutia.Akad. Nauk Sib. Div. Yakut. Branch Ser. Geol., No. 6, PP. 106-122.RussiaBlank
DS1975-0271
1976
Gnevushev, M.A.Dymnikova, N.G., Gnevushev, M.A., et al.Temperature Influence on Behaviour of Chromium Ions During Synthesis of Pyrope.Zap. Vses. Mineral. Obshch., No. 4, PP. 472-475.RussiaMineral Chemistry
DS1970-0694
1973
Gnidchin, V.M.Gnidchin, V.M., Gordeyev, S.G.The Possibility of Using the Method of Ultra-long Waves And radio Check and Test Point for the Exploration of Kimberlite Pipes.Razved. Vyssh. Uchebn. Zaved. Izv., No. 12, PP. 125-129.Russia, YakutiaKimberlite, Geophysics
DS2003-0333
2003
Gnos, E.Di Pierro, S., Gnos, E., Grobety, B.H., Armbruster, T., Bernasconi, S.M., Ulmer, P.Rock forming moissanite ( natural a-silicon carbide)American Mineralogist, Vol. 88, pp. 1817-21.Aegean SeaGeochemistry
DS200412-0450
2003
Gnos, E.Di Pierro, S., Gnos, E., Grobety, B.H., Armbruster, T., Bernasconi, S.M., Ulmer, P.Rock forming moissanite ( natural a-silicon carbide).American Mineralogist, Vol. 88, pp. 1817-21.TechnologyGeochemistry
DS200812-0409
2008
Gnos, E.Gies, J., Schreurs, G., Berger, A., Herweigh, M., Gnos, E.Indenter tectonics in central Madagascar.Geotectonic Research, Vol. 95, suppl. 1 pp. 51-53.Africa, MadagascarTectonics
DS201602-0201
2016
Gnos, E.Di Pierro, S., Gnos, E.Ca-Al-silicate inclusions in natural moissanite ( SiC).American Mineralogist, Vol. 101, pp. 71-81.Europe, TurkeyMoissanite

Abstract: Hundred-micrometer-sized calcium-aluminum-silicates (CAS) inclusions occur in moissanite-4H, moissanite-15R, and moissanite-6H from Turkey. These inclusions commonly consist of tabular exsolution lamellae of two different minerals. By combined electron microprobe and Raman spectroscopy analysis, at least eight different, essentially Mg- and Fe-free Ca-Al-silicate or Al-silicate phases have been discerned. The most common phase is dmisteinbergite, a hexagonal modification of CaAl2Si2O8, occurring in association with lamellae of Cax(Al,Si)1?xO3 or Ca1?x(Al,Si)2+xO5 compositions. All three phases contain significant amounts of BaO (up to 2 mol% of celsiane component in dmisteinbergite), SrO, SO3, and light rare earth elements (LREE). In particular, Ca1?x(Al,Si)2+xO5 contains up to 2.1 wt% of LREE, 3.9 wt% of F, and significant traces of Cl, while it is also associated to osbornite (TiN). Pure ghelenite, Ca2Al2SiO7, and three additional compositions, namely CaAl4-xSixO7, Ca1-x(Al,Si)3+xO6, and Ca3-x(Al,Si)6+xO14 have been found, either occurring as single grains or forming exsolution lamellae. They also contain significant amounts of BaO, SrO, SO3, and LREE. One last intriguing phase is composed in average of 65.9 wt% SiO2, 17.4% Al2O3, 3.0% alkalis, 6.0% BaO, 2.0% CaO+MgO, 0.9% ZrO2, and up to 0.5% LREE. Dmisteinbergite and ghelenite show Raman peaks in very good agreement with literature data, Cax(Al,Si)1-xO3 shows main Raman modes at 416 and 1009 cm?1, Ca1-x(Al,Si)3+xO6 at 531 and 1579 cm?1 while Ca3-x(Al,Si)6+xO14 has a strong peak at 553 cm?1. CaAl4-xSixO7 shows a weak Raman pattern, while Ca1-x(Al,Si)2+xO5 has no detectable Raman modes. Since the association moissanite-CAS is thermodynamically not stable at ambient pressure and moissanite crystals hosting the CAS phases have ?13C values typical of deep-mantle origin, we interpret the CAS inclusions as partially retrogressed HP minerals. Striking analogies exist between observed CAS compositions and experimentally obtained HP-HT mineralogy. For instance, Cax(Al,Si)1-xO3 contains up to 25 mol% of Al2O3, which is considered as the upper limit of alumina solubility in Ca-perovskite. The study confirms that CAS phases are an important mantle depository for large ion lithophile elements (LILE) and LREE.
DS200712-0365
2007
Gobalek, G.Gobalek, G., Scmelling, H.Earth's core formation aided by flow channelling induced by Rayleigh Taylor Instabilities.Plates, Plumes, and Paradigms, 1p. abstract p. A336.MantleMelting
DS1990-0581
1990
Gobba, J.M.Gobba, J.M.Kimberlite exploration in TanzaniaJournal of African Earth Sciences, Vol. 9, No. 3/4, pp. 565-578TanzaniaExploration -geophysics, geochemistry, Heavy mineral sampling
DS1991-0584
1991
Gobba, J.M.Gobba, J.M.The geology and mineralogy of some kimberlites in the Mwadui areaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 116-118TanzaniaPetrology, Mineralogy
DS1996-0537
1996
Gobba, J.M.Gobba, J.M.Characteristics of diamonds in TanzaniaAfrica Geoscience Review, Vol. 3, No. 2, pp. 273-293.TanzaniaReview, valuation, gem categories, Deposit -Mwadui
DS1998-1496
1998
Gobbels, M.Ulmer, G.C., Grandstaff, D., Gobbels, M., Woermann, E.An experimental delineation of the oxygen fugacity of moissanite ( SiC)bearing silicate systems.7th International Kimberlite Conference Abstract, pp. 932-33.GlobalMineral chemistry, Moissanite
DS1998-1588
1998
Gobbels, M.Woermann, E., Gobbels, M., Ulmer, G.C., Grandstaff, D.Moissanite and its bearing on the oxygen fugacity of the deeper regimes Of the Earth's upper mantle.7th International Kimberlite Conference Abstract, pp. 958-9.MantleMoissanite, Peridotite xenoliths
DS200912-0805
2009
GobboWalter, M.J., Bulanova, G.P., Armstrong, L.S., Keshav, S., Blundy, Gudfinnsson, Lord, Lennie, Clark, GobboPrimary carbonatite melt from deeply subducted oceanic crust.Nature, Vol. 459, July 31, pp. 622-626.South America, Brazil, MantleMelting, geochemistry
DS1998-0599
1998
Gobbo, L.Heaman, L., Teixeira, N.A., Gobbo, L., Gaspar, J.C.uranium-lead (U-Pb) mantle zircon ages for kimberlites from the Juin a and ParanatingaProvinces, Brasil.7th International Kimberlite Conference Abstract, pp. 322-4.BrazilGeochronology, Deposit - Juina
DS201012-0079
2010
Gobbo, L.Bulanova, G.P., Walter, M.J., Smith, C.B.,Kohn, C.C.,Armstrong, L.S., Blundy, J.,Gobbo, L.Mineral inclusions in sublithospheric diamonds from Collier 4 kimberlite pipe, Juina, Brazil: subducted protoliths, carbonated melts and primary kimberlite ..Contributions to Mineralogy and Petrology, Vol. 160, 4, pp. 489-50.South America, BrazilMagmatism
DS201212-0018
2012
Gobbo, L.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
DS201212-0675
2012
Gobbo, L.Smith, C.B., Bulanova, G.P., Walter, M.U., Kohn, S.C., Mikhail, S., Gobbo, L.Origin of diamonds from the Dachine ultramafic, French Guyana.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, French GuianaDeposit - Dachine
DS201608-1396
2016
Gobbo, L.Burnham, A.D., Bulanova, G.P., Smith, C.B., Whitehead, S.C., Kohn, S.C., Gobbo, L., Walter, M.J.Diamonds from the Machado River alluvial deposit, Rondona, Brazil, derived from both lithospheric and sublithospheric mantle.Lithos, in press available, 15p.South America, BrazilMorphology, textures, chemistry

Abstract: Diamonds from the Machado River alluvial deposit have been characterised on the basis of external morphology, internal textures, carbon isotopic composition, nitrogen concentration and aggregation state and mineral inclusion chemistry. Variations in morphology and features of abrasion suggest some diamonds have been derived directly from local kimberlites, whereas others have been through extensive sedimentary recycling. On the basis of mineral inclusion compositions, both lithospheric and sublithospheric diamonds are present at the deposit. The lithospheric diamonds have clear layer-by-layer octahedral and/or cuboid internal growth zonation, contain measurable nitrogen and indicate a heterogeneous lithospheric mantle beneath the region. The sublithospheric diamonds show a lack of regular sharp zonation, do not contain detectable nitrogen, are isotopically heavy (?13CPDB predominantly ? 0.7 to ? 5.5) and contain inclusions of ferropericlase, former bridgmanite, majoritic garnet and former CaSiO3-perovskite. This suggests source lithologies that are Mg- and Ca-rich, probably including carbonates and serpentinites, subducted to lower mantle depths. The studied suite of sublithospheric diamonds has many similarities to the alluvial diamonds from Kankan, Guinea, but has more extreme variations in mineral inclusion chemistry. Of all superdeep diamond suites yet discovered, Machado River represents an end-member in terms of either the compositional range of materials being subducted to Transition Zone and lower mantle or the process by which materials are transferred from the subducted slab to the diamond-forming region.
DS201611-2142
2016
Gobbo, L.Smith, C.B., Walter, M.J., Bulanova, G.P., Mikhail, S., Burnham, A.D., Gobbo, L., Kohn, S.C.Diamonds from Dachine, French Guiana: a unique record of Early Proterozoic subduction.Lithos, in press available 66p.South America, French GuianaDeposit - Dachine

Abstract: Diamonds from Dachine, French Guiana, are unique among worldwide diamond populations. The diamonds were transported to the surface in an unusual ultramafic extrusive magma with an affinity to boninite or komatiite, which was emplaced within an arc geological setting at ~ 2.2 Ga. Dachine diamonds have internal and external morphologies indicative of relatively rapid growth from carbon oversaturated fluids or melts, and exhibit internal features consistent with residence in a high-strain environment. On the basis of nitrogen (N) defects the diamonds are categorized as Type Ib-IaA. The unusually low aggregation state of N places severe constraints on the thermal history of the diamonds, effectively ruling out derivation in convecting mantle. The carbon and N isotopic compositions of Dachine diamonds are consistent with a sedimentary source of carbon, with the majority of diamonds having ?13C values < ? 25‰ and ?15N values > + 4‰. The primary carbon was presumably deposited on an early Proterozoic seafloor. Sulphide inclusions have low Ni and Cr and are comparable to lithospheric eclogitic-type sulphide inclusions. Three garnet and one clinopyroxene inclusion are also eclogitic in composition, and one garnet inclusion has a majorite component indicating an origin around 250 km depth. The silicate inclusions are highly depleted in many incompatible trace elements (e.g. LREE, Nb, Hf, Zr), and modelling indicates an eclogitic source lithology that contained a LREE-enriched trace phase such as epidote or allanite, and an HFSE-rich phase such as rutile. Four of the five inclusions are unusually enriched in Mn, as well as Ni and Co, and modelling indicates a protolith with the bulk composition of subducted normal MORB plus about 10% ferromanganese crust component. We suggest a model wherein Dachine diamonds precipitated from remobilized sedimentary carbon at the slab-mantle interface from liquids derived ultimately by deserpentinization of slab peridotite at depths of ~ 200 to 250 km. These fluids may also trigger melting in wedge peridotite, resulting in a volatile-rich ultramafic melt that transports the diamonds rapidly to the surface. The process of diamond formation and exhumation from the slab mantle interface likely occurred in a Paleoproterozoic subduction zone and over a very limited timespan, likely less than a million years.
DS2000-0429
2000
Gobeil, A.Hynes, A., Indares, A., Rivers, T., Gobeil, A.Lithoprobe line 55: integration of out of plane seismic results with surface structure, metamorphism....Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.341-58.QuebecGeochronology, Tectonics - Grenville
DS1859-0041
1830
Gobel, F.Engelhardt, M., Gobel, F.Die Lagerstatte der Diamanten im Ural-gebirge. UntersuchungRiga: Wilhelm Ferdinand Hacker., 26P.Russia, Urals, BrazilKimberlite
DS1995-2092
1995
Goble, R.J.Xu, Anshun, Goble, R.J., Treves, S.B.Distribution of rare earth elements in the rocks and minerals of the ElkCreek carbonatite.Geological Society of America (GSA) Abstracts, Vol. 27, No. 3, p. 98.NebraskaCarbonatite, Rare earths
DS1998-0211
1998
Goble, R.J.Carlson, M.P., Treves, S.B., Goble, R.J.New dat a and interpretations of the tectonic history of the Precambrian, mid continent USAGeological Society of America (GSA) Annual Meeting, abstract. only, p.A290.MidcontinentTectonics, Geochronology
DS1999-0255
1999
Goble, R.J.Goble, R.J., Ghazi, A.M., Treves, S.B.Mineralogy and geochemistry of Proterozoic alkaline basaltic intrusions, southwestern Alberta.Canadian Mineralogist, Vol. 37, No. 1, Feb. pp. 163-76.AlbertaAlkaline rocks, Spionkop Ridge
DS1900-0116
1902
Goch, S.F.Goch, S.F.The Diamond Mining Laws in the Transvaal, Natal, Cape Colony and Orange Free State. Vaal RiverJohannesburg: J.g. Juta., 32P.Africa, South AfricaLegal
DS1991-1512
1991
Gochin, R.J.Schena, G.D., Bevilacqua, P., Gochin, R.J.Refinements of model of economic evaluation of preconcentrationTransactions of the Institute of Mining and Metallurgy (IMM), Sect. C., Jan-April pp. C57-C61GlobalMineral processing, Economics
DS1992-1338
1992
Gochin, R.J.Schena, G.D., Gochin, R.J., Spencer, R.Assessing impact of a mineral project on the economy of a developing country -part 1: input-output modelsInstitute of Mining and Metallurgy (IMM) Transactions, Vol. 101, pp. A 29-A35GlobalEconomics, ore reserves, Ranking mineral projects
DS1992-1339
1992
Gochin, R.J.Schena, G.D., Gochin, R.J., Spencer, R.Assessing impact of a mineral project on the economy of a developing country- part 2: cost /benefit analysisTransactions of the Institute of Mining and Metallurgy (IMM), Vol. 100, pp. A181-A188NamibiaEconomics, Diamond mining mentioned
DS2001-0390
2001
Gochnauer, K.Gochnauer, K.Diamonds are the Northwest Territories best friendProspectors and Developers Association of Canada (PDAC) Exploration and development Highlights, pp. 31-4.Northwest TerritoriesKimberlites, Exploration - discoveries
DS201012-0192
2010
Gochnauer, K.Falck, H., Gochnauer, K., Irwin, D.2010 Northwest Territories mineral exploration overview.Northwest Territories Geoscience Office, Nov. 28, 21p.Canada, Northwest Territoriesdiamonds pp. 8-10.
DS1994-0056
1994
Gochnour, L.P.Antony, J.J., Gochnour, L.P.Closure costs (pay me now and pay me later)American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, Meeting held Albuquerque Feb. 14-17th, No. 94-57, 2pUnited StatesLegal -environmental, Gold, silver
DS1994-0631
1994
Gocht, W.Gocht, W., Petersen, U.Minerals and the Common Fund for CommoditiesNatural Resources forum, Vol. 18, No. 2, May pp. 143-151AfricaEconomics, Common fund for commodities
DS1997-0394
1997
Godano, R.F.Giampaolo, C., Godano, R.F., Barrese, E.The alteration of leucite bearing rocks: a possible mechanismEuropean Journal of Mineralogy, Vol. 9, No. 6, Nov. 1, pp. 1277-1292.ItalyLeucite
DS1989-0519
1989
Godard, A.Godard, A.Weathered mantle (saprolites) over basement rocks of high latitudesZeitschrift fur Geomorphologie, Suppl. Band 72, 175p. North America pp. 125-162AppalachiaSaprolites, Weathering
DS1993-1790
1993
Godard, G.Yang, Jianjun, Godard, G., Kienast, J-R., Yongzheng Lu, JinxiongUltrahigh pressure ( 60 Kbar) magnesite-bearing garnet peridotites from northeastern Jiangsu, China.Journal of Geology, Vol. 101, No. 5, September pp. 541-554.ChinaEclogites, Shandong Province
DS1995-0644
1995
Godard, G.Godard, G., Van Roemund, H.L.M.Deformation induced clinopyroxene fabrics from eclogitesJournal of Structural Geol., Vol. 17, No. 10, pp. 1425-1444.GlobalEclogites, Not specific to diamond exploration
DS1995-0645
1995
Godard, G.Godard, G., Van Roermund, H.L.M.Deformation induced clinopyroxene fabrics from eclogitesJournal of Structural Geology, Vol. 17, No. 10, pp. 1425-1444GlobalTectonics - deformation
DS1999-0256
1999
Godard, G.Godard, G., Smith, D.Preiswerkite and Sodium, magnesium, iron margaite in eclogitesContributions to Mineralogy and Petrology, Vol. 136, No. 1-2, pp. 20-32.GlobalMineralogy, Eclogites
DS2001-0391
2001
Godard, G.Godard, G.Eclogites and their geodynamic interpretation: a historyJournal of Geodynamics, Vol. 32, No. 1-2, pp. 165-203.MantleEclogites, Tectonics
DS2001-0742
2001
Godard, G.Mauler, A., Godard, G., Kunze, K.Crystallographic fabrics of omphacite, rutile and quartz in Vendee eclogites. Consequences - deformationTectonophysics, Vol. 342, No. 1-2, Dec. pp. 81-112.FranceArmorican Massif, Eclogites
DS201212-0676
2013
Godard, G.Smith, D.C., Godard, G.A raman spectroscopic study of diamond and disordered sp3-carbon in the coesite bearing straumen eclogite pod, Norway.Journal of Metamorphic Geology, Vol. 31, pp. 19-33.Europe, NorwayEclogite
DS201312-0842
2013
Godard, G.Smith, D.C., Godard, G.A raman spectrroscopic study of diamond and disordered sp3 carbon in the coesite bearing Starumen eclogite pod, Norway.Journal of Metamorphic Geology, Vol. 31, pp. 19-33.Europe, NorwayCoesite
DS201312-0843
2013
Godard, G.Smith, D.C., Godard, G.A Raman spectroscopic study of diamond and disordered sp3-carbon in the coesite bearing Straumen eclogite pod.Journal of Metamorphic Geology, Vol. 31, 1, pp. 19-33.Europe, NorwayCoesite
DS201412-0300
2014
Godard, G.Godard, G., Chabou, M.C., Adjerid, Z.First African diamonds discovered in Algeria by the ancient Arabo-Berbers: history and insight into the source rocks.Comptes Rendus Geoscience, Vol. 346, 7-8, pp. 179-189.Africa, AlgeriaHistory, lamproite
DS201412-0301
2011
Godard, G.Godard, G., Frizzotti, M-L., Palmeri, R., Smith, D.C.Origin of high pressure disordered metastable phases ( Lonsdaleite and incipiently amorphized quartz) in metamorphic rocks: geodynamic shock or crystal-scale overpressure? In: Ultrahigh Pressure Metamorphism: 25 years after discovery of coesite and diamond. Eds. Dobrzhinetskaya, L., Cuthbert, S., Faryad, W., Elsevier Publ. Pp. 125-148.MantleUHP
DS201412-0848
2013
Godard, G.Smith, D.C., Godard, G.A Raman spectroscopic study of diamond and disordered sp3-carbon in the coesite-bearing Straumen Eclogite Pod, Norway.Journal of Metamorphic Geology, Vol. 31, pp. 19-33.Europe, NorwayEclogite
DS1993-1129
1993
Godard, M.Nicolas, A., Freydier, Cl., Godard, M., Vauchez, A.Magma chambers at oceanic ridges: how large?Geology, Vol. 21, No. 1, January pp. 53-56GlobalMagma, Geophysics -seismics
DS202009-1615
2020
Godard, M.Cannao, E., Scambelluri, M., Bebout, G.E., Agostini, S., Pettke, T., Godard, M., Crispini, L.Ophicarbonate evolution from seafloor to subduction and implications for deep-Earth C cycling.Chemical Geology, Vol. 546, 119626 29p. PdfMantlecarbon, subduction

Abstract: The chemical and physical processes operating during subduction-zone metamorphism can profoundly influence the cycling of elements on Earth. Deep-Earth carbon (C) cycling and mobility in subduction zones has been of particular recent interest to the scientific community. Here, we present textural and geochemical data (CO, Sr isotopes and bulk and in-situ trace element concentrations) for a suite of ophicarbonate rocks (carbonate-bearing serpentinites) metamorphosed over a range of peak pressure-temperature (P-T) conditions together representing a prograde subduction zone P-T path. These rocks, in order of increasing peak P-T conditions, are the Internal Liguride ophicarbonates (from the Bracco unit, N. Apennines), pumpellyite- and blueschist-facies ophicarbonates from the Sestri-Voltaggio zone (W. Ligurian Alps) and the Queyras (W. Alps), respectively, and eclogite-facies ophicarbonates from the Voltri Massif. The Bracco oceanic ophicarbonates retain breccia-like textures associated with their seafloor hydrothermal and sedimentary origins. Their trace element concentrations and ?18OVSMOW (+15.6 to +18.2‰), ?13CVPDB (+1.1 to +2.5‰) and their 87Sr/86Sr (0.7058 to 0.7068), appear to reflect equilibration during Jurassic seawater-rock interactions. Intense shear deformation characterizes the more deeply subducted ophicarbonates, in which prominent calcite recrystallization and carbonation of serpentinite clasts occurred. The isotopic compositions of the pumpellyite-facies ophicarbonates overlap those of their oceanic equivalents whereas the most deformed blueschist-facies sample shows enrichments in radiogenic Sr (87Sr/86Sr?=?0.7075) and depletion in 13C (with ?13C as low as ?2.0‰). These differing textural and geochemical features for the two suites reflect interaction with fluids in closed and open systems, respectively. The higher-P-metamorphosed ophicarbonates show strong shear textures, with coexisting antigorite and dolomite, carbonate veins crosscutting prograde antigorite foliation and, in some cases, relics of magnesite-nodules enclosed in the foliation. These rocks are characterized by lower ?18O (+10.3 to 13.0‰), enrichment in radiogenic Sr (87Sr/86Sr up to 0.7096) and enrichment in incompatible and fluid-mobile element (FME; e.g., As, Sb, Pb). These data seemingly reflect interaction with externally-derived metamorphic fluids and the infiltrating fluids likely were derived from dehydrating serpentinites with hybrid serpentinite-sediment compositions. The interaction between these two lithologies could have occurred prior to or after dehydration of the serpentinites elsewhere. We suggest that decarbonation and dissolution/precipitation processes operating in ancient subduction zones, and resulting in the mobilization of C, are best traced by a combination of detailed field and petrographic observations, C, O and Sr isotope systematics (i.e., 3D isotopes), and FME inventories. Demonstration of such processes is key to advancing our understanding of the influence of subduction zone metamorphism on the mobilization of C in subducting reservoirs and the efficiency of delivery of this C to depths beneath volcanic arcs and into the deeper mantle.
DS201112-0430
2011
Godard, V.Heneyi, G., Godard, V., Cattin, R., Connolly, J.A.D.Incorporating metamorphism in geodynamic models: the mass conservation problem.Geophysical Journal International, In press available,MantleTectonics
DS1991-0808
1991
Goddard, D.A.Jones, E.J.W., Goddard, D.A., Mitchell, J.G., Banner, F.T.Lamprophyric volcanism of Cenozoic age on the Sierra Leone rise-implications for regional tectonics and the stratigraphic time scaleMarine Geology, Vol. 99, No. 1-2, July pp. 19-28Sierra LeoneTectonics, Volcanics
DS2001-0392
2001
Goddard, I.A.Goddard, I.A., Onley, P., Staude, W.The 2001 independent review of the VALMIN code (1998): a work in progressValmin 01, Mineral Asset Valuation Oct. 25-6th., pp.206-8.AustraliaEconomics - legal code, Mineral reserves, resources, valuation, exploration
DS202009-1612
2020
Goddard, R.M.Bidgood, A.K., Parsons, A.J., Lloyd, G.E., Wtares, D.J., Goddard, R.M.EBSD-based criteria for coesite-to-quartz transformation.Journal of Metamorphic Geology, doi.org/10/111/jmg.12566Mantlecoesite

Abstract: Ultrahigh?pressure (UHP) metamorphism observed in continental terranes implies that continental crust can subduct to ~40 kbar before exhuming to the surface. This process is one of the least understood and widely debated parts of the orogenic cycle. The dominantly felsic composition of UHP continental terranes means that many petrology?based techniques for determining peak pressures and temperatures are often not possible. In such cases, the detection of UHP conditions depends on the preservation of coesite, a rarely preserved mineral in exhumed UHP terranes as it rapidly transforms to quartz on decompression. Consequently, the qualitative identification of palisade quartz microstructures that form during the retrograde transformation of coesite to quartz is often used to identify UHP terranes. In this study, we conduct EBSD and misorientation analysis of palisade quartz inclusions in the coesite?bearing pyrope quartzite from the Dora Maira massif in the Alps, and matrix?scale palisade quartz in the Polokongka La granite from Tso Morari in the Ladakh Himalaya, in order to quantitatively define crystallographic characteristics of quartz after coesite. The repeatability of our observations in two unrelated occurrences of UHP rocks supports our interpretation that the following features provide a systematic and predictable set of criteria to identify the coesite to quartz transition: (1) Quartz crystallographic orientations define spatially and texturally distinct subdomains of palisade quartz grains with ‘single crystal’ orientations defined by distinct c?axis point?maxima. (2) Adjacent subdomains are misorientated with respect to each other by a misorientation angle/axis of 90°/. (3) Within each subdomain, palisade quartz grain boundaries commonly have intra? and inter?granular misorientations of 60°/[0001], consistent with the dauphiné twin law. Our observations imply that the coesite?to?quartz transformation is crystallographically controlled by the epitaxial nucleation of palisade quartz on the former coesite grain, specifically on potential coesite twin planes such as (101) and (021).
DS2001-0393
2001
Godderis, Y.Godderis, Y., Francois, L.M., Veizer, J.The early Paleozoic carbon cycleEarth and Planetary Science Letters, Vol. 190, No. 3-4, pp. 181-96.MantleCarbon cycle
DS200512-0243
2004
Godderis, Y.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
Godderis, Y.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
DS201201-0845
2011
Godderis, Y.Godderis, Y., Le Hir, G., Donnadieu, Y.Modelling the Snowball Earth.The Geological Record of Neoproterozoic glaciations, Memoirs 2011; Vol. 36, pp. 151-161.GlobalSnowball - model
DS202001-0034
2019
Godderis, Y.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.
DS1998-0518
1998
Goddin, W.Goddin, W.When it is time to make a quick exitMining Eng, Vol. 50, No. 3, March pp. 13-14GlobalMining companies, Safety - planning
DS202104-0579
2021
Godet, A.Godet, A., Guilmette, C.,Labrousse, L., Smit, M.A., Cutts, J.A., Davis, D.W., Vanier, M-A.Lu-Hf garnet dating and the timing of collisions: Paleoproterozoic accretionary tectonics revealed in the southeastern Churchill Province Trans-Hudson Orogen, Canada. Torngat, New QuebecJournal of Metamorphic Geology, doi:10.1111/jmg.12599Canada, Quebeccratons

Abstract: Dating the onset of continental collision is fundamental in defining orogenic cycles and their effects on regional tectonics and geodynamic processes through time. Part of the Palaeoproterozoic Trans?Hudson Orogen, the Southeastern Churchill Province (SECP) is interpreted to result from the amalgamation of Archean to Palaeoproterozoic crustal blocks (amalgamated as the central Core Zone) that diachronically collided with the margins of the North Atlantic and Superior cratons, resulting in two bounding transpressive orogens: the Torngat and New Quebec Orogens. The SECP exposes mainly gneissic middle to lower orogenic crust in which deformation and amphibolite to granulite facies metamorphism and anatexis overprinted the early geological features classically used to constrain the timing of collisional events. To enable improved tectonic models for the development of the SECP, and the Trans?Hudson as a whole, we investigated granulite facies supracrustal sequences from the Tasiuyak Complex (TC) accretionary prism and the western margin of the North Atlantic Craton-that is, Saglek Block (upper plate)-using a multi?chronometer approach coupled with trace element geochemistry. In particular, the use of garnet Lu-Hf geochronology provides an important minimal time constraint for crustal thickening and collision. Garnet growth in the TC is constrained at 1885 ± 12 Ma (Lu-Hf), indistinguishable from U-Pb age of prograde monazite at 1873 ± 5 Ma. Zircon growth during melt crystallization occurred at 1848 ± 12 Ma. Garnet from the overriding Saglek Block is dated at 2567 ± 4.4 Ma (Lu-Hf) and indicates that gneissic rocks from the upper plate did not record the metamorphic imprint of the Torngat Orogeny. The diachronicity of the integrated metamorphic record across the strike of the SECP is explained by the location of terrane boundaries, consistent with the westward growth of the Churchill plate margin through sequential amalgamation of narrow crustal blocks during accretionary tectonics from c. 1.9 to 1.8 Ga.
DS202111-1767
2021
Godet, A.Godet, A., Guilmette, C., Labrousse, L., Smit, M.A., Cutts, J.A., Davis, D.W., Vanier, M-A.Lu-Hf garnet dating and the timing of collisions: Paleoproterozoic accretionary tectonics revealed in the southeastern Churchill Province, Trans-Hudson orogen, Canada.Journal of Metamorphic Geology, Vol. 39, 8, 31p. PdfCanadageochronology

Abstract: Dating the onset of continental collision is fundamental in defining orogenic cycles and their effects on regional tectonics and geodynamic processes through time. Part of the Palaeoproterozoic Trans-Hudson Orogen, the Southeastern Churchill Province (SECP) is interpreted to result from the amalgamation of Archean to Palaeoproterozoic crustal blocks (amalgamated as the central Core Zone) that diachronically collided with the margins of the North Atlantic and Superior cratons, resulting in two bounding transpressive orogens: the Torngat and New Quebec Orogens. The SECP exposes mainly gneissic middle to lower orogenic crust in which deformation and amphibolite to granulite facies metamorphism and anatexis overprinted the early geological features classically used to constrain the timing of collisional events. To enable improved tectonic models for the development of the SECP, and the Trans-Hudson as a whole, we investigated granulite facies supracrustal sequences from the Tasiuyak Complex (TC) accretionary prism and the western margin of the North Atlantic Craton—that is, Saglek Block (upper plate)—using a multi-chronometer approach coupled with trace element geochemistry. In particular, the use of garnet Lu-Hf geochronology provides an important minimal time constraint for crustal thickening and collision. Garnet growth in the TC is constrained at 1885 ± 12 Ma (Lu-Hf), indistinguishable from U-Pb age of prograde monazite at 1873 ± 5 Ma. Zircon growth during melt crystallization occurred at 1848 ± 12 Ma. Garnet from the overriding Saglek Block is dated at 2567 ± 4.4 Ma (Lu-Hf) and indicates that gneissic rocks from the upper plate did not record the metamorphic imprint of the Torngat Orogeny. The diachronicity of the integrated metamorphic record across the strike of the SECP is explained by the location of terrane boundaries, consistent with the westward growth of the Churchill plate margin through sequential amalgamation of narrow crustal blocks during accretionary tectonics from c. 1.9 to 1.8 Ga.
DS200412-0680
2004
Godey, S.Godey, S., Deschamps, F., Trampert, J., Sneider, R.Thermal and compositional anomalies beneath the North American continent.Journal of Geophysical Research, Vol. 109, B1, 10.1029/2003 JB002263United States, CanadaGeothermometry
DS200512-0281
2005
Godey, S.Faure, S., Fallara, F., Godey, S.3D architecture of the North American lithosphere by seismic tomography: implications for regional diamond exploration.Quebec Exploration Conference, 1p. abstractCanada, QuebecTomography
DS201012-0036
2010
Godfrey, I.S.Bangert, U., Barnes, R., Gass, M.H., Bleoch, A.L., Godfrey, I.S.Vacancy clusters, dislocations and brown coloration in diamond.Journal of Physics Condensed Matter, Vol. 21, 36, pp. 364208-213..TechnologyDiamond crystallography
DS201012-0081
2009
GodfriedBurns, 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
DS200512-0391
2004
Godfried, H.Hall, C., Godfried, H.Diamond anvils.Rough Diamond Review, No. 6, Sept.pp.Diamond anvil
DS200412-1624
2004
Godhavari, K.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
DS200412-1843
2004
Godhavari, K.S.Singh, U.P., Venkatesh, N.S., Godhavari, K.S., et al.Lamprophyre dykes in Chotanagpur gneissic complex, near Simdega Gumla District Jkarkhand.Journal of the Geological Society of India, Vol. 63, 6, pp. 655-658.IndiaLamprophyre, drainage basin
DS1987-0688
1987
Godik, E.E.Smirnova, O.I., Godik, E.E., Gontar, A.G.Long lived excited states of boron in diamondSoviet Physics Jetp, Vol. 21, No. 7, July pp. 774-777GlobalBlank
DS1989-0520
1989
Godin, E.Godin, E.Diamond exploration program for SouthWest ArkansawContinental Precious Minerals Promotional literature, 8pArkansasNews item, CPM.
DS200712-0599
2006
Godin, L.Law, R.D., Searle, M.P., Godin, L.Channel flow, ductile extrusion and exhumation in continental collision zones.Geological Society of London , SP 268, Nov. 632p. $ 225. www.geolsoc.org.uk/bookshopCanadaGeodynamics
DS1995-0646
1995
Godin, M.J.Godin, M.J., King, T.W.Provincial/Territorial mining tax law roundupMining Tax Strategies, Held Feb. 1995, 55pCanadaTaxation, Mining tax
DS1993-0701
1993
Godin, P.D.Hrabi, R.B., Grant, J.W., Godin, P.D., Helmstaedt, H., King, J.E.Geology of the Winter Lake supracrustal belt, central Slave Province, District of Mackenzie, N.W.T.Geological Survey Canada Paper, No. 93-1C, pp. 71-82Northwest TerritoriesWinter Lake, Regional geology
DS1900-0557
1907
Goding, F.W.Goding, F.W.Diamonds from QueenslandU.s. Daily Cons. Report, No. 2819, MARCH 10TH.Australia, QueenslandDiamond
DS1982-0005
1982
Godivier, R.Albouy, J., Godivier, R.Gravimetric Maps of the Central African RepublicNational Technical Information Service, NASA CR 169596, 14P.GlobalBouguer, Gravity, Geophysics
DS1975-0516
1977
Godlevskii, M.N.Godlevskii, M.N., Gurkina, G.A.Octahedron Cube Morphogenetic Series of Diamond CrystalsZapiski Veses. Mineral. Obshch., No. 6, PP. 641-650.RussiaCrystallography
DS1986-0416
1986
Godon, R.H.Kane, M.F., Godon, R.H.Gravity and magnetic evidence of the structural framework of the continental United StatesGeological Society of America (GSA) Abstract Volume, Vol. 18, No. 6, p. 651. (abstract.)MidcontinentGeophysics
DS1998-0553
1998
Godoy, A.M.Hackspacher, P.C., Godoy, A.M.Vertical displacement during post collisional escape tectonism ( BrasilianoOrogeny) of the Ribeira Belt.Journal of African Earth Sciences, Vol. 27, 1A, p. 99. AbstractBrazilTectonics, Orogeny
DS1999-0279
1999
Godoy, A.M.Hackspacher, P.C., Godoy, A.M.Vertical displacement during late collisional escape tectonics (BrasilianoOrogeny) in the Ribeira Belt.Journal of African Earth Sciences, Vol. 29, No. 1, July pp. 25-32.Brazil, Sao PauloTectonics, Orogeny
DS202005-0728
2020
Godoy, L.H.Conceicao, F.T., Vasconcelos, P.M., Godoy, L.H., Navarro, G.R.B.40Ar/40Ar geochronological evidence for multiple magmatic events during the emplacement of Tapira alkaline-carbonatite complex, Minas Gerais, Brazil.Journal of South American Earth Sciences, Vol. 97, 102416, 7p. PdfSouth America, Brazil, Minas Geraiscarbonatite

Abstract: The Alto Parnaíba Igneous Province (APIP) is a voluminous magmatic province composed of various alkaline-carbonatite complexes emplaced in the Brasilia Mobile Belt during the Cretaceous. Relative timing of emplacement of silicate and carbonate magmas in most of these complexes remains mostly unresolved due to conflicting geochronological results. To determine the duration of magmatism and to test the possible existence of multiple magmatic events, we employ 40Ar/39Ar phlogopite single crystal dating to determine the history of magma emplacement at the Tapira alkaline-carbonatite complex, Minas Gerais, Brazil. The new single crystal data indicate at least two magmatic events during the emplacement of this complex, the first at > 96.2 ± 0.8 Ma and the second at 79.15 ± 0.6 Ma. The first igneous event was responsible for emplacement of the silicate plutonic series, while the second event corresponds to the emplacement of primarily carbonatitic magmas, generating metasomatic phlogopite alteration in bebedourites. The ages of intrusion and cooling of the alkaline-carbonatite complexes in the APIP must be investigated in other complexes to determine if intrusion intervals of ~17 Ma or more are common regionally. Protracted intrusive events, if related to magma generation by passage of South America over a stationary Trindade plume, requires complex ponding and lateral magma flow below a slow-moving continent.
DS1989-0521
1989
Godson, R.H.Godson, R.H., Mall, M.R.Potential field geophysical programs for IBM compatible microcomputers, version 1.0; documentationUnited States Geological Survey (USGS) Open File, No. 89-0197-A-F, paper 4.00 discs @ 6.00 30.00GlobalComputer, Program -geophysics
DS1975-0283
1976
Godwin, C.I.Godwin, C.I.Kimberlitic Diatremes and Dykes in the Mackenzie Fold Belt, yukon and Adjacent Northwest Territories.Paper Presented At The 4th. Geoscience Forum, Whitehorse, Yu, UNPUBL.Canada, Yukon, Northwest TerritoriesGeology
DS1975-0517
1977
Godwin, C.I.Godwin, C.I., Mcarthur, M., Mcarthur, G.Geology of the Mountain Diatreme: a Possible Kimberlite in The Mackenzie Fold Belt, Northwest Territories.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC)/SEG/CGU ANNUAL MEETING, HELD VANCOUVER., Vol. 2, P. 21. (abstract.).Canada, Northwest TerritoriesGeology
DS1980-0226
1980
Godwin, C.I.Mcarthur, M.L., Tipnis, R.S., Godwin, C.I.Early and Middle Ordovician Conodont Fauna from the Mountain Diatreme, Northern Mackenzie Mountains, District of Mackenzie.Geological Survey of Canada (GSC) PAPER., No. 80-1A, PP. 363-368.Canada, Northwest TerritoriesPaleontology
DS1985-0237
1985
Godwin, C.I.Godwin, C.I., Price, B.J.Geology of the Mountain Diatreme Kimberlite, North Central Mackenzie Mountains, District of Mackenzie, Northwest Territories.The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) SPECIAL VOLUME., IN PRESS, REPRINT 28P. 8 TABLES, 25 FIGS.Canada, Northwest TerritoriesSayunei Range, Geology, Petrography, Lithology, Geochemistry
DS1987-0252
1987
Godwin, C.I.Godwin, C.I., Price, B.J.Geology of the Mountain diatreme kimberlite, north central MackenzieMountains, District of Mackenzie, Northwest TerritoriesMineral Deposits of Northern Cordillera, The Canadian Institute of Mining, Metallurgy and Petroleum (CIM), Special Paper Vol No. 37, pp.. 298-310Northwest TerritoriesCanada, Diatreme
DS1970-0916
1974
Godza, V.Godza, V.Le Diamant En R.c.aSci. Amic. Fr., Vol. 4, No. 5, PP. 12-13.GlobalDiamond
DS1987-0771
1987
Goebel, E.D.Voveney, R.M.Jr., Goebel, E.D., Zeller, E.J., Dreschhoff, G.A.M.Serpentinization and the origin of hydrogen gas in KansasAmerican Association of Petroleum Geologists (AAPG) Bulletin, Vol. 71, No. 1 Jan. pp. 39-48KansasMidcontinent, Tectonics
DS1989-0522
1989
Goebel, E.D.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
DS201212-0244
2012
Goemann, K.Giuliani, A., Kamenetsky, V.S., Kendrick, M.A., Phillips, D., Goemann, K.Nickel rich metasomatism of the lithospheric mantle by pre-kimberlitic alkali S Cl rich C-O-H fluids.Contributions to Mineralogy and Petrology, in press availableAfrica, South AfricaDeposit - Bultfontein
DS201212-0245
2012
Goemann, K.Giuliani, A., Kamenetsky, V.S., Phillips, D., Kendrick, M.A., Wyatt, B.A., Goemann, K.Nature of alkali-carbonate fluids in the sub-continental lithospheric mantle.Geology, Vol. 40, 11, pp. 967-970.Mantle, RussiaDeposit - Udachnaya
DS201212-0246
2012
Goemann, K.Giuliani, A.,Kamenetsky, V.S., Lendrick, M.A., Phillips, D., Goemann, K.Nickel-rich metasomatism of the lithospheric mantle by pre-kimberlitic alkali-S-Cl-rich C-O-H fluids.Contributions to Mineralogy and Petrology, in press available 17p.MantleMetasomatism
DS201412-0294
2014
Goemann, K.Giuliani, A., Phillips, D., Kamenetsky, V.S., Kendrick, M.A., Wyatt, B.A., Goemann, K., Hutchinson, G.Petrogenesis of mantle polymict breccias: insights into mantle processes coeval with kimberlite magmatism.Journal of Petrology, Vol. 55, 4, pp. 831-858.Africa, South AfricaDeposit - Bultfontein
DS201412-0438
2014
Goemann, K.Kamenetsky, V.S., Belousova, E.A., Giuliani, A., Kamenetsky, M.B., Goemann, K., Griffin, W.L.Chemical abrasion of zircon and ilmenite megacrysts in the Monastery kimberlite: implications for the composition of kimberlite melts.Chemical Geology, Vol. 383, pp. 76-85.Africa, South AfricaDeposit - Monastery
DS201601-0018
2016
Goemann, K.Giuliani, A., Phillips, D., Kamenetsky, V.S., Goemann, K.Constraints on kimberlite ascent mechanisms revealed by phlogopite compositions in kimberlites and mantle xenoliths.Lithos, Vol. 240, pp. 189-201.Africa, South AfricaDeposit - Bultfontein

Abstract: Kimberlite magmas are of economic and scientific importance because they represent the major host to diamonds and are probably the deepest magmas from continental regions. In addition, kimberlite magmas transport abundant mantle and crustal xenoliths, thus providing fundamental information on the composition of the sub-continental lithosphere. Despite their importance, the composition and ascent mechanism(s) of kimberlite melts remain poorly constrained. Phlogopite is one of the few minerals that preserves a history of fluid migration and magmatism in the mantle and crust and is therefore an invaluable petrogenetic indicator of kimberlite magma evolution. Here we present major and trace element compositional data for phlogopite from the Bultfontein kimberlite (Kimberley, South Africa; i.e. the kimberlite type-locality) and from entrained mantle xenoliths. Phlogopite macrocrysts (~ > 0.3-0.5 mm) and microcrysts (between ~ 0.1 and 0.3 mm) in the Bultfontein kimberlite display concentric compositional zoning patterns. The cores of these phlogopite grains exhibit compositions typical of phlogopite contained in peridotite mantle xenoliths. However, the rims of some grains show compositions analogous to kimberlite groundmass phlogopite (i.e. high Ti, Al and Ba; low Cr), whereas other rims and intermediate zones (between cores and rims) exhibit unusually elevated Cr and lower Al and Ba concentrations. The latter compositions are indistinguishable from matrix phlogopite in polymict breccia xenoliths (considered to represent failed kimberlite intrusions) and from Ti-rich overgrowth rims on phlogopite in other mantle xenoliths. Consequently, it is likely that these phlogopite grains crystallized from kimberlite melts and that the high Ti-Cr zones originated from earlier kimberlite melts at mantle depths. We postulate that successive pulses of ascending kimberlite magma progressively metasomatised the conduit along which later kimberlite pulses ascended, producing progressively decreasing interaction with the surrounding mantle rocks. In our view, these processes represent the fundamental mechanism of kimberlite magma ascent. Our study also indicates that, in addition to xenoliths/xenocrysts and magmatic phases, kimberlite rocks incorporate material crystallized at various mantle depths by previous kimberlite intrusions (mantle-derived ‘antecrysts’).
DS201611-2133
2016
Goemann, K.Potter, N.J., Kamenetsky, V.S., Simonetti, A., Goemann, K.Different types of liquid immiscibility in carbonatite magmas: a case study of the Oldoinyo Lengai 1993 lava and melt inclusions.Chemical Geology, in press available 9p.Africa, TanzaniaDeposit - Oldoinyo Lengai

Abstract: Oldoinyo Lengai is situated within the Gregory Rift Valley (northern Tanzania) and is the only active volcano erupting natrocarbonatite lava. This study investigates the texture and mineralogy of the June 1993 lava at Oldoinyo Lengai, and presents petrographic evidence of liquid immiscibility between silicate, carbonate, chloride, and fluoride melt phases. The 1993 lava is a porphyritic natrocarbonatite consisting of abundant phenocrysts of alkali carbonates, nyerereite and gregoryite, set in a quenched groundmass, composed of sodium carbonate, khanneshite, Na-sylvite and K-halite, and a calcium fluoride phase. Dispersed in the lava are silicate spheroids (< 2 mm) with a cryptocrystalline silicate mineral assemblage wrapped around a core mineral. We have identified several textural features preserved in the silicate spheroids, melt inclusions, and carbonatite groundmass that exhibit evidence of silicate-carbonate, carbonate-carbonate and carbonate-halide immiscibility. Rapid quenching of the lava facilitated the preservation of the end products of these liquid immiscibility processes within the groundmass. Textural evidence (at both macro- and micro-scales) indicates that the silicate, carbonate, chloride and fluoride phases of the lava unmixed at different stages of evolution in the magmatic system.
DS201707-1327
2017
Goemann, K.Giuliani, A., Soltys, A., Phillips, D., Kamenetsky, V.S., Maas, R., Goemann, K., Woodhead, J.D., Drysdale, R.N., Griffin, W.L.The final stages of kimberlite petrogenesis: petrography, mineral chemistry, melt inclusions and Sr-C-O isotope geochemistry of the Bultfontein kimberlite ( Kimberley, South Africa.Chemical Geology, Vol. 455, pp. 342-256.Africa, South Africadeposit - Bultfontein

Abstract: The petrogenesis of kimberlites is commonly obscured by interaction with hydrothermal fluids, including deuteric (late-magmatic) and/or groundwater components. To provide new constraints on the modification of kimberlite rocks during fluid interaction and the fractionation of kimberlite magmas during crystallisation, we have undertaken a detailed petrographic and geochemical study of a hypabyssal sample (BK) from the Bultfontein kimberlite (Kimberley, South Africa). Sample BK consists of abundant macrocrysts (> 1 mm) and (micro-) phenocrysts of olivine and lesser phlogopite, smaller grains of apatite, serpentinised monticellite, spinel, perovskite, phlogopite and ilmenite in a matrix of calcite, serpentine and dolomite. As in kimberlites worldwide, BK olivine grains consist of cores with variable Mg/Fe ratios, overgrown by rims that host inclusions of groundmass phases (spinel, perovskite, phlogopite) and have constant Mg/Fe, but variable Ni, Mn and Ca concentrations. Primary multiphase inclusions in the outer rims of olivine and in Fe-Ti-rich (‘MUM’) spinel are dominated by dolomite, calcite and alkali carbonates with lesser silicate and oxide minerals. Secondary inclusions in olivine host an assemblage of Na-K carbonates and chlorides. The primary inclusions are interpreted as crystallised alkali-Si-bearing Ca-Mg-rich carbonate melts, whereas secondary inclusions host Na-K-rich C-O-H-Cl fluids. In situ Sr-isotope analyses of groundmass calcite and perovskite reveal similar 87Sr/86Sr ratios to perovskite in the Bultfontein and the other Kimberley kimberlites, i.e. magmatic values. The ?18O composition of the BK bulk carbonate fraction is above the mantle range, whereas the ?13C values are similar to those of mantle-derived magmas. The occurrence of different generations of serpentine and occasional groundmass calcite with high 87Sr/86Sr, and elevated bulk carbonate ?18O values indicate that the kimberlite was overprinted by hydrothermal fluids, which probably included a significant groundwater component. Before this alteration the groundmass included calcite, monticellite, apatite and minor dolomite, phlogopite, spinel, perovskite and ilmenite. Inclusions of groundmass minerals in olivine rims and phlogopite phenocrysts show that olivine and phlogopite also belong to the magmatic assemblage. We therefore suggest that the crystallised kimberlite was produced by an alkali-bearing, phosphorus-rich, silica-dolomitic melt. The alkali-Si-bearing Ca-Mg-rich carbonate compositions of primary melt inclusions in the outer rims of olivine and in spinel grains with evolved compositions (MUM spinel) support formation of these melts after fractionation of abundant olivine, and probably other phases (e.g., ilmenite and chromite). Finally, the similarity between secondary inclusions in kimberlite olivine of this and other worldwide kimberlites and secondary inclusions in minerals of carbonatitic, mafic and felsic magmatic rocks, suggests trapping of residual Na-K-rich C-O-H-Cl fluids after groundmass crystallisation. These residual fluids may have persisted in pore spaces within the largely crystalline BK groundmass and subsequently mixed with larger volumes of external fluids, which triggered serpentine formation and localised carbonate recrystallisation.
DS201707-1357
2017
Goemann, K.Potter, N.J., Kamenetsky, V.S., Simonetti, A., Goemann, K.Different types of liquid immiscibility in carbonatite magmas: a case stufy of the Oldoinyo Lengai 1993 lava and melt inclusions.Chemical Geology, Vol. 455, pp. 376-384.Africa, Tanzaniadeposit - Oldoinyo Lengai

Abstract: Oldoinyo Lengai is situated within the Gregory Rift Valley (northern Tanzania) and is the only active volcano erupting natrocarbonatite lava. This study investigates the texture and mineralogy of the June 1993 lava at Oldoinyo Lengai, and presents petrographic evidence of liquid immiscibility between silicate, carbonate, chloride, and fluoride melt phases. The 1993 lava is a porphyritic natrocarbonatite consisting of abundant phenocrysts of alkali carbonates, nyerereite and gregoryite, set in a quenched groundmass, composed of sodium carbonate, khanneshite, Na-sylvite and K-halite, and a calcium fluoride phase. Dispersed in the lava are silicate spheroids (< 2 mm) with a cryptocrystalline silicate mineral assemblage wrapped around a core mineral. We have identified several textural features preserved in the silicate spheroids, melt inclusions, and carbonatite groundmass that exhibit evidence of silicate-carbonate, carbonate-carbonate and carbonate-halide immiscibility. Rapid quenching of the lava facilitated the preservation of the end products of these liquid immiscibility processes within the groundmass. Textural evidence (at both macro- and micro-scales) indicates that the silicate, carbonate, chloride and fluoride phases of the lava unmixed at different stages of evolution in the magmatic system.
DS201708-1563
2017
Goemann, K.Abersteiner, A., Kamanetsky, V.S., Kamenetsky, M., Goemann, K., Ehrig, K., Rodemann, T.Significance of halogens ( F, Cl) in kimberlite melts: insights from mineralogy and melt inclusions in the Roger pipe ( Ekati, Canada).Chemical Geology, in press available, 16p.Canada, Northwest Territoriesdeposit, Roger, Ekati

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

Abstract: Monticellite is a magmatic and/or deuteric mineral that is often present, but widely varying in concentrations in Group-I (or archetypal) kimberlites. To provide new constraints on the petrogenesis of monticellite and its potential significance to kimberlite melt evolution, we examine the petrography and geochemistry of the minimally altered hypabyssal monticellite-rich Leslie (Canada) and Pipe 1 (Finland) kimberlites. In these kimberlites, monticellite (Mtc) is abundant (25–45 vol%) and can be classified into two distinct morphological types: discrete and intergrown groundmass grains (Mtc-I), and replacement of olivine (Mtc-II). Monticellite in group-I kimberlites: Implications for evolution of parental melts and post-emplacement CO 2 degassing (PDF Download Available).
DS201802-0216
2018
Goemann, K.Abersteiner, A., Kamenetsky, V.S., Kamenetsky, M., Goemann, K., Ehrig, K., Rodemann, T.Significance of halogens ( F, Cl) in kimberlite melts: insights from mineralogy and melt inclusions in the Roger pipe ( Ekati, Canada).Chemical Geology, Vol. 478, pp. 148-163.Canada, Northwest Territoriesdeposit - Roger

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

Abstract: Monticellite is a magmatic and/or deuteric mineral that is often present, but widely varying in concentrations in Group-I (or archetypal) kimberlites. To provide new constraints on the petrogenesis of monticellite and its potential significance to kimberlite melt evolution, we examine the petrography and geochemistry of the minimally altered hypabyssal monticellite-rich Leslie (Canada) and Pipe 1 (Finland) kimberlites. In these kimberlites, monticellite (Mtc) is abundant (25-45 vol%) and can be classified into two distinct morphological types: discrete and intergrown groundmass grains (Mtc-I), and replacement of olivine (Mtc-II). Primary multiphase melt inclusions in monticellite, perovskite and Mg-magnetite contain assemblages dominated by alkali (Na, K, Ba, Sr)-enriched Ca-Mg-carbonates, chlorides, phosphates, spinel, silicates (e.g. olivine, phlogopite) and sulphides. These melt inclusions probably represent snapshots of a variably differentiated kimberlite melt that evolved in-situ towards carbonatitic and silica-poor compositions. Although unconstrained in their concentration, the presence of alkali-carbonates and chlorides in melt inclusions suggests they are a more significant component of the kimberlite melt than commonly recorded by whole-rock analyses. We present petrographic and textural evidence showing that pseudomorphic Mtc-II resulted from an in-situ reaction between olivine and the carbonate component of the kimberlite melt in the decarbonation reactio. This reaction is supported by the preservation of abundant primary inclusions of periclase and to a lesser extent Fe-Mg-oxides in monticellite, perovskite and Mg-magnetite. Based on the preservation of primary periclase inclusions, we infer that periclase also existed in the groundmass, but was subsequently altered to brucite. We suggest that CO2 degassing in the latter stages of kimberlite emplacement into the crust is largely driven by the observed reaction between olivine and the carbonate melt. For this reaction to proceed, CO2 should be removed (i.e. degassed), which will cause further reaction and additional degassing in response to this chemical system change (Le Chatelier's principle). Our study demonstrates that these proposed decarbonation reactions may be a commonly overlooked process in the crystallisation of monticellite and exsolution of CO2, which may in turn contribute to the explosive eruption and brecciation processes that occur during kimberlite magma emplacement and pipe formation.
DS201808-1764
2018
Goemann, K.Lim, E., Giuliani, A., Phillips, D., Goemann, K.Origin of complex zoning in olivine from diverse, Diamondiferous kimberlites and tectonic settings: Ekati ( Canada), Alto Paranaiba ( Brazil) and Kaalvallei ( South Africa).Mineralogy and Petrology, doi.org/10.1007/s00710-018-0607-6 16p.Canada, Northwest Territories, South America, Brazildeposit - Ekati, Grizzly, Kaola, Limpeza-18, Tres Ranchos-04, Kaalvallei, Samada, New Robinson

Abstract: Olivine in kimberlites can provide unique insights into magma petrogenesis, because it is the most abundant xenocrystic phase and a stable magmatic product over most of the liquid line of descent. In this study we examined the petrography and chemistry of olivine in kimberlites from different tectonic settings, including the Slave craton, Canada (Ekati: Grizzly, Koala), the Brasilia mobile belt (Limpeza-18, Tres Ranchos-04), and the Kaapvaal craton, South Africa (Kaalvallei: Samada, New Robinson). Olivine cores display a wide range of compositions (e.g., Mg#?=?78-95). The similarity in olivine composition, resorption of core zones and inclusions of mantle-derived phases, indicates that most olivine cores originated from the disaggregation of mantle peridotites, including kimberlite-metasomatised lithologies (i.e. sheared lherzolites and megacrysts). Olivine rims typically show a restricted range of Mg#, with decreasing Ni and increasing Mn and Ca contents, a characteristic of kimberlitic olivine worldwide. The rims host inclusions of groundmass minerals, which implies crystallisation just before and/or during emplacement. There is a direct correlation between olivine rim composition and groundmass mineralogy, whereby high Mg/Fe rims are associated with carbonate-rich kimberlites, and lower Mg/Fe rims are correlated with increased phlogopite and Fe-bearing oxide mineral abundances. There are no differences in olivine composition between explosive (Grizzly) and hypabyssal (Koala) kimberlites. Olivine in kimberlites also displays transitional zones and less common internal zones, between cores and rims. The diffuse transitional zones exhibit intermediate compositions between cores and rims, attributed to partial re-equilibration of xenocrystic cores with the ascending kimberlite melt. In contrast, internal zones form discrete layers with resorbed margins and restricted Mg# values, but variable Ni, Mn and Ca concentrations, which indicates a discrete crystallization event from precursor kimberlite melts at mantle depths. Overall, olivine exhibits broadly analogous zoning in kimberlites worldwide. Variable compositions for individual zones relate to different parental melt compositions rather than variations in tectonic setting or emplacement mechanism.
DS201811-2552
2018
Goemann, K.Abersteiner, A., Kamenetsky, V.S., Golovin, A.V., Kamenetsky, M., Goemann, K.Was crustal contamination involved in the formation of the serpentine-free Udachnaya-East kimberlite? New insights into parental melts, liquids, liquidus assemblage and effects of alteration.Journal of Petrology, Vol. 59, 8, pp. 1467-1492.Russiadeposit - Udachnaya-East

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

Abstract: The Benfontein kimberlite is a renowned example of a sill complex and provides an excellent opportunity to examine the emplacement and evolution of intrusive kimberlite magmas. We have undertaken a detailed petrographic and melt inclusion study of the Benfontein Upper, Middle and Lower sills. These sills range in thickness from 0.25 to 5?m. New perovskite and baddeleyite U/Pb dating produced ages of 85.7?±?4.4?Ma and 86.5?±?2.6?Ma, respectively, which are consistent with previous age determinations and indicate emplacement coeval with other kimberlites of the Kimberley cluster. The Benfontein sills are characterised by large variations in texture (e.g., layering) and mineral modal abundance between different sill levels and within individual samples. The Lower Sill is characterised by carbonate-rich diapirs, which intrude into oxide-rich layers from underlying carbonate-rich levels. The general paucity of xenogenic mantle material in the Benfontein sills is attributed to its separation from the host magma during flow differentiation during lateral spreading. The low viscosity is likely responsible for non-explosive emplacement of the Benfontein sills, while the rhythmic layering is attributed to multiple magma injections. The Benfontein sills are marked by the excellent preservation of olivine and groundmass mineralogy, which is composed of monticellite, spinel, perovskite, baddeleyite, ilmenite, apatite, calcite, dolomite along with secondary serpentine and glagolevite [NaMg6[Si3AlO10](OH,O)8•H2O]. This is the first time glagolevite is reported in kimberlites. Groundmass spinel exhibits atoll-textures and is composed of a magnesian ulvöspinel magnetite (MUM) or chromite core, surrounded by occasional pleonaste and a rim of Mg-Al-magnetite. We suggest that pleonaste crystallised as a magmatic phase, but was resorbed back into the residual host melt and/or removed by alteration. Analyses of secondary inclusions in olivine and primary inclusions in monticellite, spinel, perovskite, apatite and interstitial calcite are largely composed of Ca-Mg carbonates and, to a lesser extent, alkali-carbonates and other phases. These inclusions probably represent the entrapment of variably differentiated parental kimberlite melts, which became progressively more enriched in carbonate, alkalis, halogens and sulphur during crystal fractionation. Carbonate-rich diapirs from the Lower Sill contain more exotic phase assemblages (e.g., Ba-Fe titanate, barite, ancylite, pyrochlore), which probably result from the extreme differentiation of residual kimberlite melts followed by physical separation and isolation from the parental carbonate-rich magma. It is likely that any alkali or halogen rich minerals crystallising in the groundmass were removed from the groundmass during syn?/post-magmatic alteration, or in the case of Na, remobilised to form secondary glagolevite. The Benfontein sill complex therefore provides a unique example of how the composition of kimberlites may be modified after magma emplacement in the upper crust.
DS201901-0057
2018
Goemann, K.Potter, N.J., Ferguson, M.R.M., Kamenetsky, V.S., Chakhmouradian, A.R., Sharygin, V.V., Thompson, J.M., Goemann, K.Textural evolution of perovskite in the Afrikanda alkaline-ultramafic complex, Kola Peninsula.Contributions to Mineralogy and Petrology, Vol. 173, 12, pp. 106-Russia, Kola Peninsuladeposit - Afrikanda

Abstract: Perovskite is a common accessory mineral in a variety of mafic and ultramafic rocks, but perovskite deposits are rare and studies of perovskite ore deposits are correspondingly scarce. Perovskite is a key rock-forming mineral and reaches exceptionally high concentrations in olivinites, diverse clinopyroxenites and silicocarbonatites in the Afrikanda alkaline-ultramafic complex (Kola Peninsula, NW Russia). Across these lithologies, we classify perovskite into three types (T1-T3) based on crystal morphology, inclusion abundance, composition, and zonation. Perovskite in olivinites and some clinopyroxenites is represented by fine-grained, equigranular, monomineralic clusters and networks (T1). In contrast, perovskite in other clinopyroxenites and some silicocarbonatites has fine- to coarse-grained interlocked (T2) and massive (T3) textures. Electron backscatter diffraction reveals that some T1 and T2 perovskite grains in the olivinites and clinopyroxenites are composed of multiple subgrains and may represent stages of crystal rotation, coalescence and amalgamation. We propose that in the olivinites and clinopyroxenites, these processes result in the transformation of clusters and networks of fine-grained perovskite crystals (T1) to mosaics of more coarse-grained (T2) and massive perovskite (T3). This interpretation suggests that sub-solidus processes can lead to the development of coarse-grained and massive perovskite. A combination of characteristic features identified in the Afrikanda perovskite (equigranular crystal mosaics, interlocked irregular-shaped grains, and massive zones) is observed in other oxide ore deposits, particularly in layered intrusions of chromitites and intrusion-hosted magnetite deposits and suggests that the same amalgamation processes may be responsible for some of the coarse-grained and massive textures observed in oxide deposits worldwide.
DS201902-0254
2019
Goemann, K.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Giuliani, A., Howarth, G.H., Castillo-Oliver, M., Thompson, J., Kamenetsky, M., Cherry, A.Composition and emplacement of the Benfontein kimberlite sill complex ( Kimberley, South Africa): textural, petrographic and melt inclusion constraints.Lithos, Vol. 324-325, pp. 297-314.Africa, South Africadeposit - Benfontein

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

Abstract: Djerfisherite (K6(Fe,Ni,Cu)25S26Cl) occurs as an accessory phase in the groundmass of many kimberlites, kimberlite-hosted mantle xenoliths, and as a daughter inclusion phase in diamonds and kimberlitic minerals. Djerfisherite typically occurs as replacement of pre-existing Fe-Ni-Cu sulphides (i.e. pyrrhotite, pentlandite and chalcopyrite), but can also occur as individual grains, or as poikilitic phase in the groundmass of kimberlites. In this study, we present new constraints on the origin and genesis of djerfisherite in kimberlites and their entrained xenoliths. Djerfisherite has extremely heterogeneous compositions in terms of Fe, Ni and Cu ratios. However, there appears to be no distinct compositional range of djerfisherite indicative of a particular setting (i.e. kimberlites, xenoliths or diamonds), rather this compositional diversity reflects the composition of the host kimberlite melt and/or interacting metasomatic medium. In addition, djerfisherite may contain K and Cl contents less than the ideal formula unit. Raman spectroscopy and electron backscatter diffraction (EBSD) revealed that these K-Cl poor sulphides still maintain the same djerfisherite crystal structure. Two potential mechanisms for djerfisherite formation are considered: (1) replacement of pre-existing Fe-Ni-Cu sulphides by djerfisherite, which is attributed to precursor sulphides reacting with metasomatic K-Cl bearing melts/fluids in the mantle or the transporting kimberlite melt; (2) direct crystallisation of djerfisherite from the kimberlite melt in groundmass or due to kimberlite melt infiltration into xenoliths. The occurrence of djerfisherite in kimberlites and its mantle cargo from localities worldwide provides strong evidence that the metasomatising/infiltrating kimberlite melt/fluid was enriched in K and Cl. We suggest that kimberlites originated from melts that were more enriched in alkalis and halogens relative to their whole-rock compositions.
DS201905-1014
2019
Goemann, K.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Golovin, A.V., Gornova, M.A.Polymineralic inclusions in kimberlite hosted megacrysts: implications for kimberlite melt evolution.Lithos, doi.101016/j.lithos .2019.04.004 42p.Canada, Northwest Territories, Russiadeposit - Diavik, Jericho, Leslie, Udachnaya East

Abstract: Megacrysts are large (cm to >20?cm in size) mantle-derived crystals, which are commonly entrained by kimberlite magmas, comprising of olivine, orthopyroxene, clinopyroxene, phlogopite, garnet, ilmenite and zircon as common phases. Numerous studies have shown megacrysts to contain polymineralic inclusions, which have been interpreted to represent entrapped kimberlite melt. To constrain the origin of these inclusions in megacrysts and their relationship to kimberlite magmatism, we present a detailed petrographic and geochemical study of clinopyroxene and olivine megacrysts and their hosted inclusions from the Diavik, Jericho, Leslie (Slave Craton, Canada) and Udachnaya-East (Siberian Craton, Russia) kimberlites. The studied megacrysts are between 1 and 3?cm in size and representative of both the Cr-rich and Cr-poor suites. Megacrysts contain two types of inclusions: i. Large (<0.5-5?mm in size) round-to-irregular shaped polymineralic inclusions, which are composed of minerals similar to the host kimberlite groundmass, and consist of olivine, calcite, spinel, perovskite, phlogopite and apatite (± serpentine, alkali-carbonates, alkali-chlorides, barite). ii. Swarms/trails of ‘micro melt inclusions’ (MMI; <1-5??m in size), which surround polymineralic inclusions, veins and fractures, thereby forming a ‘spongy’ texture. MMIs generally contain multiphase assemblages similar to polymineralic inclusions as well as various additional phases, such as alkali-carbonates or alkali-chlorides, which are typically absent in polymineralic inclusions and the surrounding kimberlite groundmass. Textural and geochemical evidence suggests that polymineralic inclusions in megacrysts crystallised from kimberlite melt, which infiltrated along fracture/vein networks. The polymineralic inclusion assemblages resulted from disequilibria reactions between the host megacryst and infiltrating kimberlite melt, which was likely enhanced by rapidly changing conditions during magmatic ascent. The connectivity of polymineralic inclusions to the kimberlite groundmass via network veins/fractures suggests that they are susceptible to infiltrating post-emplacement fluids. Therefore, the vast majority of polymineralic inclusions are unlikely to represent ‘pristine’ entrapped kimberlite melt. In contrast, MMIs are isolated within megacrysts (i.e. not connected to fractures/veins and therefore shielded from post-magmatic fluids) and probably represent entrapped remnants of the variably differentiated kimberlite melt, which was more enriched in alkalis-Cl-S-CO2 than serpentinised polymineralic inclusions and the host rocks exposed at Earth's surface as kimberlites.
DS201907-1527
2019
Goemann, K.Batanova, V.G., Thompson, J.M., Danyushevsky, L.V., Portnyagin, M.V., Garbe-Schonberg, D., Hauri, E., Kimura, J-I., Chang, Q., Senda, R., Goemann, K., Chauvel, C., Campillo, S., Ionov, D.A., Sobolev,A.V.New olivine reference material for in situ microanalysis.Geostandards and Geoanalytical Research, in press available, 21p.Asia, Mongoliaolivine

Abstract: A new olivine reference material - MongOL Sh11?2 - for in situ analysis has been prepared from the central portion of a large (20 × 20 × 10 cm) mantle peridotite xenolith from a ~ 0.5 My old basaltic breccia at Shavaryn?Tsaram, Tariat region, central Mongolia. The xenolith is a fertile mantle lherzolite with minimal signs of alteration. Approximately 10 g of 0.5-2 mm gem quality olivine fragments were separated under binocular microscope and analysed by EPMA, LA?ICP?MS, SIMS and bulk analytical methods (ID?ICP?MS for Mg and Fe, XRF, ICP?MS) for major, minor and trace elements at six institutions world?wide. The results show that the olivine fragments are sufficiently homogeneous with respect to major (Mg, Fe, Si), minor and trace elements. Significant inhomogeneity was revealed only for phosphorus (homogeneity index of 12.4), whereas Li, Na, Al, Sc, Ti and Cr show minor inhomogeneity (homogeneity index of 1-2). The presence of some mineral and fluid?melt micro?inclusions may be responsible for the inconsistency in mass fractions obtained by in situ and bulk analytical methods for Al, Cu, Sr, Zr, Ga, Dy and Ho. Here we report reference and information values for twenty?seven major, minor and trace elements.
DS202003-0329
2020
Goemann, K.Abersteiner, A., Kamenetsky, V.S., Goemann, K.A genetic study of olivine crystallization in the Mark kimberlite ( Canada) revealed by zoning and melt inclusions.Lithos, In press available 46p. pdf.Canada, Northwest Territoriesdeposit - Mark

Abstract: Elucidating the composition of primary kimberlite melts is essential to understanding the nature of their source, petrogenesis, rheology, transport and ultimately the origin of diamonds. Kimberlite rocks are typically comprised of abundant olivine (~2560 vol%), which occurs as individual grains of variable size and morphology, and includes xenocrysts and zoned phenocrysts. Zoning patterns and inclusions in olivine can be used to decipher the petrogenetic history of kimberlites, starting from their generation in the mantle through to emplacement in the crust. This study examines well-preserved, euhedral, zoned olivine crystals from the Mark kimberlite (Lac de Gras, Canada). Olivine typically consists of xenocrystic cores, which are homogeneous in composition but vary widely between grains (Fo88.193.6). These cores are in turn surrounded by (in order of crystallisation) magmatic rims and Mg-rich rinds (Fo95.398.1). In addition, we document a new type of olivine zone (‘outmost rind’) that overgrows Mg-rich rinds. Crystal and melt/fluid inclusions are abundant in olivine and preserve a record of kimberlite melt evolution. For the first time in the studies of kimberlite olivine, we report primary melt inclusions hosted in Mg-rich olivine rinds. In addition, we observe that pseudosecondary melt/fluid inclusions are restricted to interior olivine zones (cores, rims) and are considered to have formed prior to rind formation. Pseudosecondary melt/fluid inclusions are inferred to have been entrapped at depth, as evidenced by measured densities in thermometric experiments of CO2 and decrepitation haloes, indicating a minimum entrapment pressure of ~200450 MPa (or ~615 km). Both primary and pseudosecondary melt inclusions in olivine have daughter minerals dominated by CaMg and K-Na-Ba-Sr-bearing carbonates, K-Na-chlorides along with subordinate silicates (e.g., phlogopite, monticellite), Fe-Mg-Al-Ti-spinel, perovskite, phosphates and sulphates/sulphides and periclase. In addition to phases reported in primary melt inclusions, pseudosecondary melt inclusions contain more diverse and exotic daughter mineral assemblages, where they contain phases such as tetraferriphlogopite Ba- or K-sulphates, kalsilite and Na-phosphates. The daughter mineral assemblages are consistent with a silica-poor, alkali dolomitic carbonatite melt. We demonstrate that the different types of inclusions in olivine can assist in constraining the timing of multi-stage olivine growth and the composition of the crystallising melt. The large variance in olivine zoning patterns, morphologies and Ni distribution (i.e. both coupling with and decoupling from Fo) indicates that olivine in the studied Mark kimberlite samples represent an accumulation of olivine, where olivine was derived from successive stages of the ascending magma and/or from multiple, but related pulses of magma. Primary and pseudosecondary melt/fluid inclusions in olivine indicate that a variably differentiated silica-poor, halogen-bearing, alkali-dolomitic melt crystallised and transported olivine in the Mark kimberlite.
DS202003-0357
2020
Goemann, K.Potter, N.J., Kamenetsky, V.S., Chakhmouradian, A.R., Kamenetsky, M.B., Goemann, K., Rodemann, T.Polymineralic inclusions in oxide minerals of the Afrikanda alkaline ultramafic complex: implications for the evolution of perovskite mineralization.Contributions to Mineralogy and Petrology, Vol. 175, 13p. PdfRussiaperovskite

Abstract: The exceptional accumulation of perovskite in the alkaline-ultramafic Afrikanda complex (Kola Peninsula, Russia) led to the study of polymineralic inclusions hosted in perovskite and magnetite to understand the development of the perovskite-rich zones in the olivinites, clinopyroxenites and silicocarbonatites. The abundance of inclusions varies across the three perovskite textures, with numerous inclusions hosted in the fine-grained equigranular perovskite, fewer inclusions in the coarse-grained interlocked perovskite and rare inclusions in the massive perovskite. A variety of silicate, carbonate, sulphide, phosphate and oxide phases are assembled randomly and in variable proportions in the inclusions. Our observations reveal that the inclusions are not bona fide melt inclusions. We propose that the inclusions represent material trapped during subsolidus sintering of magmatic perovskite. The continuation of the sintering process resulted in the coarsening of inclusion-rich subhedral perovskite into inclusion-poor anhedral and massive perovskite. These findings advocate the importance of inclusion studies for interpreting the origin of oxide minerals and their associated economic deposits and suggest that the formation of large scale accumulations of minerals in other oxide deposits may be a result of annealing of individual disseminated grains.
DS202008-1365
2020
Goemann, K.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Kjarsgaard, B.A., Fedortchouk, Y., Ehrig, K., Kamenetsky, M.Evolution of kimberlite magmas in the crust: a case study of groundmass and mineral hosted inclusions in the Mark kimberlite ( Lac de Gras, Canada).Lithos, in press available, 55p. PdfCanada, Northwest Territoriesdeposit - Mark

Abstract: Kimberlites are the surface manifestation of deeply-derived (>150 km) and rapidly ascended magmas. Fresh kimberlite rocks are exceptionally rare, as most of them are invariably modified by pervasive deuteric and/or post-magmatic fluids that overprint the original mineralogy. In this study, we examined fresh archetypal kimberlite from the Mark pipe (Lac de Gras, Canada), which is characterised by well-preserved olivine and groundmass minerals. The sequence of crystallisation of the parental melt and its major compositional features, including oxygen fugacity, were reconstructed using textural relationships between magmatic minerals, their zoning patterns and crystal/melt/fluid inclusions. Crystal and multiphase primary, pseudosecondary and secondary melt/fluid inclusions in olivine, Cr-diopside, spinel, perovskite, phlogopite/kinoshitalite, apatite and calcite preserve a record of different stages of kimberlite melt evolution. Melt/fluid inclusions are generally more depleted in silica and more enriched in alkalis (K, Na), alkali-earth (Ba, Sr) and halogens (Cl, F) relative to the whole-rock composition of the Mark kimberlite. These melt/fluid inclusion compositions, in combination with presence of elevated CaO (up to 1.73 wt%), in Mg-rich olivine rinds, crystallisation of groundmass kinoshitalite, carbonates (calcite, Sr-Ba-bearing) and alkali-enriched rims around apatite suggest that there was progressive enrichment in CO2, alkalis and halogens in the evolving parental melt. The Mark kimberlite groundmass is characterised by the following stages of in-situ crystallisation: (1) olivine rims around xenocrystic cores + Cr-spinel/TIMAC. (2) Mg-rich olivine rinds around olivine rims/cores + MUM-spinel (followed by pleonaste and Mg-magnetite) + monticellite (+ partial resorption of olivine, along with the formation of ferropericlase and CO2 as a result of decarbonation reactions) + perovskite + apatite. (3) Olivine outmost rinds, which are coeval with phlogopite/kinoshitalite + apatite + sulphides + carbonate (calcite, Ba-Sr-Na-bearing varieties). In addition, oxygen fugacity of the Mark kimberlite was constrained by olivine-chromite, perovskite and monticellite oxygen barometry and showed that the parental melt became progressively more oxidised in response to fractional crystallisation. (4) Deuteric (i.e. late-stage magmatic) and/or post-magmatic (i.e. external fluids) alteration of magmatic minerals (e.g., olivine, monticellite, ferropericlase) and crystallisation of mesostasis serpentine, K-bearing chlorite and brucite (i.e. replacement of ferropericlase). The absence of any alkali (Na, K) and halogen (F, Cl) rich groundmass minerals in the Mark kimberlite may be attributed to these elements becoming concentrated in the late-stage melt where they potentially formed unstable, water-soluble carbonates (such as those observed in melt inclusions). Consequently, these minerals were most likely removed from the groundmass by deuteric and/or post-magmatic alteration.
DS202108-1266
2021
Goemann, K.Abersteiner, A., Kamenetsky, V.S., Golovin, A., Goemann, K., Ehrig, K.Dissolution of mantle orthopyroxene in kimberlitic melts: petrographic, geochemical and melt inclusion constraints from an orthopyroxenite xenolith from the Udachnaya-East kimberlite ( Siberian Craton, Russia).Lithos, Vol. 398-399, 17p. PdfRussia, Siberiadeposit - Udachnaya-East

Abstract: Reconstructing the original composition of kimberlite melts in the mantle and delineating the processes that modify them during magmatic ascent and emplacement in the crust remains a significant challenge in kimberlite petrology. One of the most significant processes commonly cited to drive initial kimberlite melts towards more Si-Mg-rich compositions and decrease the solubility of CO2 is the assimilation of mantle orthopyroxene. However, there is limited direct evidence to show the types of reactions that may occur between mantle orthopyroxene and the host kimberlite melt. To provide new constraints on the interaction between orthopyroxene and parental kimberlite melts, we examined a fresh (i.e. unmodified by secondary/post-magmatic alteration) orthopyroxenite xenolith, which was recovered from the serpentine-free units of the Udachnaya-East kimberlite (Siberian Craton, Russia). This xenolith is composed largely of orthopyroxene (~ 90%), along with lesser olivine and clinopyroxene and rare aluminous magnesian chromite. We can show that this xenolith was invaded by the host kimberlite melt along grain interstices and fractures, where it partially reacted with orthopyroxene along the grain boundaries and replaced it with aggregates of compositionally distinct clinopyroxene, olivine and phlogopite, along with subordinate Fe-Cr-Mg spinel, Fesingle bondNi sulphides and djerfisherite (K6(Fe,Ni,Cu)25S26Cl). Primary melt inclusions in clinopyroxene replacing xenolith-forming orthopyroxene, as well as secondary melt inclusion trails in xenolith orthopyroxene, clinopyroxene and olivine are composed of similar daughter mineral assemblages that consist largely of: Nasingle bondK chlorides, along with varying proportions of phlogopite, Fe-Cu-Ni sulphides, djerfisherite, rasvumite (KFe2S3), Cr-Fe-Mg spinel, nepheline and apatite, and rare rutile, sodalite, barite, olivine, Ca-K-Na carbonates and Nasingle bondK sulphates. The melt entrapped by these inclusions likely represent the hybrid products produced by the invading kimberlite melt reacting with orthopyroxene in the xenolith. The mechanism that could explain the partial replacement of orthopyroxene in this xenolith by clinopyroxene, olivine and phlogopite could be attributed to the following reaction: Orthopyroxene + Carbonatitic (melt) ? Olivine + Clinopyroxene + Phlogopite + CO2. This reaction is supported by theoretical and experimental studies that advocate the dissolution of mantle orthopyroxene within an initially silica-poor and carbonate-rich kimberlite melt. The mineral assemblages replacing orthopyroxene in the xenolith, together with hosted melt inclusions, suggests that the kimberlitic melt prior to reaction with orthopyroxene was likely carbonate-rich and Na-K-Cl-S bearing. The paucity of carbonate in the reaction zones around orthopyroxene and in melt inclusions in clinopyroxene replacing xenolith-forming orthopyroxene and xenolith minerals (orthopyroxene, clinopyroxene and olivine) is attributed to the consumption of carbonates and subsequent exsolution of CO2 by the proposed decarbonation reaction. Concluding, we propose that this orthopyroxenite xenolith provides a rare example of the types of reactions that can occur between mantle orthopyroxene and the host kimberlite melt. The preservation of this xenolith and zones around orthopyroxene present new insights into the composition and evolution of parental kimberlite melts and CO2 exsolution.
DS1860-0083
1869
Goeppert, H.R.Goeppert, H.R.Algae Enclosed in DiamondsQuarterly Journal of Geological Society, Vol. 25, PT. 2, P. 18.Africa, South AfricaGeobotany, Inclusions
DS2002-0583
2002
Goergen, E.T.Goergen, E.T., Bauer, R.L.High pressure paleoproterozoic metamorphism and isothermal decompression during multistage reworking..16th. International Conference On Basement Tectonics '02, Abstracts, 2p., 2p.Wyoming, southeastArchean Wyoming Province, Laramide Mountains
DS201312-0937
2013
Goes, A.M.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
DS201812-2794
2018
Goes, A.M.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.
DS2000-0825
2000
Goes, S.Rohm, A.H.E., Snieder, R., Goes, S., Trampert, J.Thermal structure of continental upper mantle inferred from S wave velocity and surface heat flow.Earth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.395-407.MantleGeothermometry, Geophysics - seismics
DS2002-0584
2002
Goes, S.Goes, S., Van der Lee, S.Thermal structure of the North American uppermost mantle inferred from seismic tomography.Journal of Geophysical Research, Vol. 107, No. 3, pp. ETG 2.MantleGeothermometry, Geophysics - seismics
DS2002-0585
2002
Goes, S.Goes, S., Van der Lee, S.Thermal structure of the North American uppermost mantle inferred from seismic tomography.Journal of Geophysical Research, Vol.107,B3, pp.ETG 2-1-20North America, United States, Midcontinent, WyomingSubduction, Tomography, tectonics, seismics
DS2002-0586
2002
Goes, S.Goes, S., Van der lee, S.Thermal structure of the North American uppermost mantle inferred from seismic tomography.Journal of Geophysical Research, Vol. 107, No.3, pp.United States, Canada, North AmericaGeothermometry
DS2003-0198
2003
Goes, S.Cammarano, F., Goes, S., Vacher, P., Giardini, D.Inferring upper mantle temperatures from seismic velocitiesPhysics of the Earth and Planetary Interiors, Vol. 138, 3-4, pp. 197-222.MantleGeophysics - seismics
DS200412-0255
2003
Goes, S.Cammarano, F., Goes, S., Vacher, P., Giardini, D.Inferring upper mantle temperatures from seismic velocities.Physics of the Earth and Planetary Interiors, Vol. 138, 3-4, pp. 197-222.MantleGeophysics - seismics
DS200412-0681
2004
Goes, S.Goes, S., Cammarano, F., Hanson, U.Synthetic seismic signature of thermal mantle plumes.Earth and Planetary Science Letters, Vol. 218, 3, Feb. 15, pp. 403-419.MantleGeochronology
DS200512-0131
2005
Goes, S.Cammarano, F., Deuss, A., Goes, S., Giardini, D.One dimensional physical reference models for the upper mantle and transition zone: combining seismic and mineral physics constraints.Journal of Geophysical Research, Vol. 110, B1, B01306MantleGeophysics - seismics
DS200512-0132
2005
Goes, S.Cammarano, F., Goes, S., Deuss, A., Giardini, D.Is a pyrolitic adiabatic mantle compatible with seismic data?Earth and Planetary Science Letters, Vol. 232, 3-4, April 15, pp. 227-243.MantleGeophysics - seismics
DS200512-0347
2005
Goes, S.Goes, S.Testing thermal whole mantle plumes seismically.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantleMantle plume, geophysics - seismics, convection
DS200512-0348
2005
Goes, S.Goes, S., Simons, F.J., Yoshizawa, K.Seismic constraints on temperature of the Australian upper mantle.Earth and Planetary Science Letters, Vol. 236, 1-2, pp. 227-237.AustraliaGeophysics - seismics
DS200712-0143
2007
Goes, S.Capitanio, F.A., Goes, S., Morra, G., Giardini, D.Signatures of downgoing plate buoyancy driven subduction in motions and seismic coupling at major subduction zones.Earth and Planetary Science Letters, Vol. 262, 1-2, pp. 286-306.MantleSubduction
DS200812-0232
2008
Goes, S.Conden, L., Goes, S., Cammarano, F., Connolly, J.A.Thermochemical interpretation of one dimensional seismic reference models for upper mantle: evidence for bias due to heterogeneity.Geophysical Journal International, Vol. 175, 2, pp. 627-648.MantleGeothermometry
DS200812-0418
2008
Goes, S.Goes, S., Capitanio, F.A., Morra, G.Evidence of lower mantle slab penetration phases in plate motions.Nature, Vol. 451, 7181 Feb. 21, pp. 981-984.MantleSubduction
DS200912-0118
2009
Goes, S.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
DS200912-0328
2009
Goes, S.Hwang, Y-K., Ritsema, J., Goes, S.Spatial variations of P wave attenuation in the mantle beneath North America.Journal of Geophysical Research, Vol. 114. B 6, B06312.MantleGeophysics - seismics
DS201012-0086
2010
Goes, S.Capitanio, F.A., Morra, G., Goes, S., Weinberg, R.F., Moresi, L.India Asia convergence driven by subduction of the Greater Indian continent.Nature Geoscience, Vol. 3, Jan. pp. 1-4.IndiaSubduction
DS201012-0278
2010
Goes, S.Hieronymus, C.F., Goes, S.Complex cratonic seismic structure from thermal models of the lithosphere: effects of variations in deep radiogenic heating.Geophysical Journal International, Vol. 180, no. 3, pp. 999-1022.MantleGeophysics - seismics
DS201012-0812
2010
Goes, S.Van Wijk, J.W., Baldridge, W.S., Van Hunen, J., Goes, S., Aster, R., Coblentz, D.D., Grand, S.P., Ni, J.Small scale convection at the edge of the Colorado Plateau: implications for topography, magmatism, and evolution of Proterozoic lithosphere.Geology, Vol. 38, 7, pp. 611-614.United States, Colorado PlateauMagmatism
DS201112-1014
2011
Goes, S.Styles, E., Goes, S., Van Keken, P.E., Ritsema, J., Smith, H.Synthetic images of dynamically predicted plumes and comparison with a global tomographic model.Earth and Planetary Science Letters, Vol. 311, 3-4, pp. 351-363.MantleTomography
DS201704-0615
2017
Goes, S.Agrusta, R., Goes, S., van Hunen, J.Subducting slab transition zone interaction: stagnation, penetration and mode switches.Earth and Planetary Science Letters, Vol. 464, pp. 10-23.MantleSubduction

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

Abstract: As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20–50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of –1 to –2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ?2 orders of magnitude higher than background mantle (effective yield stresses of 100–300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.
DS201805-0944
2018
Goes, S.Eeken, T., Goes, S., Pedersen, H.A., Arndt, N.T., Bouilhol, P.Seismic evidence for depth dependent metasomatism in cratons.Earth Planetary Science Letters, Vol. 491, pp. 148-159.Africa, Australia, Canada, Europegeothermometry

Abstract: The long-term stability of cratons has been attributed to low temperatures and depletion in iron and water, which decrease density and increase viscosity. However, steady-state thermal models based on heat flow and xenolith constraints systematically overpredict the seismic velocity-depth gradients in cratonic lithospheric mantle. Here we invert for the 1-D thermal structure and a depth distribution of metasomatic minerals that fit average Rayleigh-wave dispersion curves for the Archean Kaapvaal, Yilgarn and Slave cratons and the Proterozoic Baltic Shield below Finland. To match the seismic profiles, we need a significant amount of hydrous and/or carbonate minerals in the shallow lithospheric mantle, starting between the Moho and 70 km depth and extending down to at least 100-150 km. The metasomatic component can consist of 0.5-1 wt% water bound in amphibole, antigorite and chlorite, ?0.2 wt% water plus potassium to form phlogopite, or ?5 wt% CO2 plus Ca for carbonate, or a combination of these. Lithospheric temperatures that fit the seismic data are consistent with heat flow constraints, but most are lower than those inferred from xenolith geothermobarometry. The dispersion data require differences in Moho heat flux between individual cratons, and sublithospheric mantle temperatures that are 100-200?°C less beneath Yilgarn, Slave and Finland than beneath Kaapvaal. Significant upward-increasing metasomatism by water and CO2-rich fluids is not only a plausible mechanism to explain the average seismic structure of cratonic lithosphere but such metasomatism may also lead to the formation of mid-lithospheric discontinuities and would contribute to the positive chemical buoyancy of cratonic roots.
DS201806-1234
2018
Goes, S.Maquire, R., Ritsema, J., Bonnin, M., van Keken, P.E., Goes, S.Evaluating the resolution of deep mantle plumes in teleseismic traveltime tomography.Journal of Geophysical Research, Vol. 123, 1. pp. 384-400.Mantlegeophysics - seismic

Abstract: The strongest evidence to support the classical plume hypothesis comes from seismic imaging of the mantle beneath hot spots. However, imaging results are often ambiguous and it is questionable whether narrow plume tails can be detected by present?day seismological techniques. Here we carry out synthetic tomography experiments based on spectral element method simulations of seismic waves with period T > 10 s propagating through geodynamically derived plume structures. We vary the source?receiver geometry in order to explore the conditions under which lower mantle plume tails may be detected seismically. We determine that wide?aperture (4,000-6,000 km) networks with dense station coverage (<100-200 km station spacing) are necessary to image narrow (<500 km wide) thermal plume tails. We find that if uncertainties on traveltime measurements exceed delay times imparted by plume tails (typically <1 s), the plume tails are concealed in seismic images. Vertically propagating SKS waves enhance plume tail recovery but lack vertical resolution in regions that are not independently constrained by direct S paths. We demonstrate how vertical smearing of an upper mantle low?velocity anomaly can appear as a plume originating in the deep mantle. Our results are useful for interpreting previous plume imaging experiments and guide the design of future experiments.
DS201810-2364
2018
Goes, S.Perrin, A., Goes, S., Prytulak, J., Rondenay, S., Davies, D.R.Mantle wedge temperatures and their potential relation to volcanic arc location.Earth and Planetary Science Letters, Vol. 501, pp. 67-77.Mantlesubduction

Abstract: The mechanisms underpinning the formation of a focused volcanic arc above subduction zones are debated. Suggestions include controls by: (i) where the subducting plate releases water, lowering the solidus in the overlying mantle wedge; (ii) the location where the mantle wedge melts to the highest degree; and (iii) a limit on melt formation and migration imposed by the cool shallow corner of the wedge. Here, we evaluate these three proposed mechanisms using a set of kinematically-driven 2D thermo-mechanical mantle-wedge models in which subduction velocity, slab dip and age, overriding-plate thickness and the depth of decoupling between the two plates are systematically varied. All mechanisms predict, on the basis of model geometry, that the arc-trench distance, D, decreases strongly with increasing dip, consistent with the negative D-dip correlations found in global subduction data. Model trends of sub-arc slab depth, H, with dip are positive if H is wedge-temperature controlled and overriding-plate thickness does not exceed the decoupling depth by more than 50 km, and negative if H is slab-temperature controlled. Observed global H-dip trends are overall positive. With increasing overriding plate thickness, the position of maximum melting shifts to smaller H and D, while the position of the trenchward limit of the melt zone, controlled by the wedge's cold corner, shifts to larger H and D, similar to the trend in the data for oceanic subduction zones. Thus, the limit imposed by the wedge corner on melting and melt migration seems to exert the first-order control on arc position.
DS201901-0035
2017
Goes, S.Goes, S., Agrusta, R., van Hunen, J., Garel, F.Subduction - transition zone interaction: a review.Geosphere, Vol. 13, 3, pp. 644-664.Mantlesubduction

Abstract: As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20-50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of -1 to -2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ?2 orders of magnitude higher than background mantle (effective yield stresses of 100-300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.
DS202008-1394
2020
Goes, S.Goes, S., Hasterok, D., Schutt, D.L., Klocking, M.Continental lithospheric temperatures: a review.Physics of the Earth and Planetary Interiors, Vol. 306, 106509, 18p. PdfMantlegeothermometry

Abstract: Thermal structure of the lithosphere exerts a primary control on its strength and density and thereby its dynamic evolution as the outer thermal and mechanic boundary layer of the convecting mantle. This contribution focuses on continental lithosphere. We review constraints on thermal conductivity and heat production, geophysical and geochemical/petrological constraints on thermal structure of the continental lithosphere, as well as steady-state and non-steady state 1D thermal models and their applicability. Commonly used geotherm families that assume that crustal heat production contributes an approximately constant fraction of 25-40% to surface heat flow reproduce the global spread of temperatures and thermal thicknesses of the lithosphere below continents. However, we find that global variations in seismic thickness of continental lithosphere and seismically estimated variations in Moho temperature below the US are more compatible with models where upper crustal heat production is 2-3 times higher than lower crustal heat production (consistent with rock estimates) and the contribution of effective crustal heat production to thermal structure (i.e. estimated by describing thermal structure with steady-state geotherms) varies systematically from 40 to 60% in tectonically stable low surface heat flow regions to 20% or lower in higher heat flow tectonically active regions. The low effective heat production in tectonically active regions is likely partly the expression of a non-steady thermal state and advective heat transport.
DS201112-0375
2010
Goes Passos, Jr.G.Goes Passos, Jr.G., De Sousa Rosa, A.Perfil do diamante no estado de Mato Grosso.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 30-31.South America, Brazil, Mato GrossoJuina, Paraguai, Paranatinga, Rio das Mortes
DS201112-0376
2010
Goes Passos, Jr.G.Goes Passos, Jr.G., Svisero, D.P., Dereppe, J-M.Caracateristicas mineralogicas do diamante da regiao de Tibagi, Parana.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 32-33.South America, Brazil, ParanaTibagi - diamond morphology
DS202202-0186
2021
Goev, A.G.Adushkin, V.V., Goev, A.G., Sanina, I.A., Fedorov, A.V.The deep velocity structure of the Central Kola Peninsula obtained using the receiver function technique.Doklady Earth Sciences, Vol. 501, pp. 1049-1051.Russia, Kola Peninsulageophysics - seismics

Abstract: New results are presented on the features of the deep velocity structure of two of the three main tectonic blocks that make up the Kola region-Murmansk and Belomorskii-by the P receiver function technique. The research is based on data from the broadband seismic stations Teriberka and Kovda. The results are compared with the models obtained by mutual inversion of PRF and SRF using the data from the stations Apatity and Lovozero. It is shown that the crust has a two-layer structure with the border at a depth of 11 km under the Murmansk block and at a depth of 15 km under the Kola and Belomorskii blocks. The crust thickness of the Murmansk, Belomorskii, and Kola blocks are 35, 33, and 40 km, respectively. The presence of the MLD was revealed in all tectonic structures analyzed for the first time, with a top at a depth of about 70 km for the Murmansk and Belomorskii blocks and 90 km for the Kola block and a bottom at 130-140 km for all structures.
DS200412-0682
2004
Goff, B.H.Goff, B.H., Weinberg, R., Groves, D.I., et al.The giant Vergenoeg fluorite deposit in a magnetite fluorite fayalite REE pipe: a hydrothermally altered carbonatite related pegMineralogy and Petrology, Vol. 80, 3-4, March pp. 173-199.Africa, South AfricaCarbonatite
DS1993-1536
1993
Goff, F.Stimac, J.A., Goff, F., Bulletinen, T.Crustal xenoliths from Clear Lake, California: granulites directly related to magmatic underplating?The Xenolith window into the lower crust, abstract volume and workshop, p. 19.CaliforniaMagma, Xenoliths
DS1993-0554
1993
Goff, J.A.Goff, J.A.A unitarian approach to modeling near-Gaussian characteristics of atopographic field.Journal of Geophysical Research, Vol. 98, No. B11, November pp. 19, 635-19, 648.GlobalTomography, Modeling -general application
DS1996-0538
1996
Goff, S.P.Goff, S.P.Arctic Islands... overview and covers diamond activities.northwest Territories Exploration overview 1995, March pp. 2-13, 14, 15.Northwest TerritoriesNews item, Update and overview company activity
DS1993-0055
1993
Goffe, .Avigad, D., Chopin, C., Goffe, ., Michard, A.Tectonic model for the evolution of the western AlpesGeology, Vol. 21, No. 7, July pp. 659-662AlpsTectonics
DS200412-0146
2003
Goffe, B.Beyssac, O., Brunet, F., Petitet, J.P., Goffe, B., Rouzard, J.N.Experimental study of the microtextural and structural deformations of carbonaceous materials under pressure and temperature.European Journal of Mineralogy, Vol. 15, no. 6, Dec. 1, pp. 937-951.TechnologyCarbon - UHP
DS201112-0377
2007
Gofton, E.L.Gofton, E.L.The Renard 4 kimberlite: implications for ascent of kimberlites in the shallow crust.Thesis: University of British Columbia Msc., 118p.Canada, QuebecThesis - note availability based on request to author
DS1975-0750
1978
Gogineni, S.V.Gogineni, S.V., Melton, C.E., Giardini, A.A.Some Petrological Aspects of the Prairie Creek Diamond Bearing Kimberlite Diatreme, Arkansaw.Contributions to Mineralogy and Petrology, Vol. 66, No. 3, PP. 251-262.United States, Gulf Coast, Arkansas, PennsylvaniaPetrology, Lamproite
DS1975-1172
1979
Gogineni, S.V.Pantaleo, N.S., Newton, G.S., Gogineni, S.V., Melton, C.E.Mineral Inclusions in Four Arkansaw Diamonds: Their Nature And Significance.American Mineralogist., Vol. 64, No. 9-10, PP. 1059-1062.United States, Gulf Coast, Arkansas, PennsylvaniaMineralogy, Mineral Chemistry
DS1975-0284
1976
Gogoleva, R.A.Gogoleva, R.A., Ilupin, I.P., Kamysheva, G.G.Influence of Basement Rocks on Kimberlite CompositionIzvestiya Akad. Nauk Sssr, Geol. Ser., 1976, 04, PP. 35-40.RussiaKimberlite, Genesis
DS1987-0397
1987
Gogte, B.S.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
DS201012-0605
2010
Gogus, O.Pysklywec, R.N., Gogus, O., Percival, J., Cruden, A.R.Insights from geodynamical modeling on possible fates of continental mantle lithosphere: collision, removal, and overturn.Canadian Journal of Earth Sciences, Vol. 47, 4, pp. 541-563,MantleGeodynamics
DS1993-0555
1993
Gohl, K.Gohl, K., Hawman, R.B., Smithson, S.B.Wide angle reflection studies of the crust and Moho beneath the Archean gneiss terrane of southern MinnesotaGeophysical Research Letters, Vol. 20, No. 7, April 9, pp. 619-622MinnesotaGeophysics, Mantle
DS1994-0632
1994
Gohl, K.Gohl, K., Smithson, S.B.Seismic wide angle study of accreted Proterozoic crust in southeasternWyoming.Earth and Planetary Science Letters, Vol. 125, pp. 293-306.WyomingGeophysics -seismics, Proterozoic crust
DS200812-0849
2007
Gohl, K.Parseigla, N., Gohl, K., Uenzelmann-Neben, G.Deep crustal structure of the sheared South African continental margin: first results of the Agulhas-Karoo Geoscience Transect.South African Journal of Geology, Vol. 110, 2-3, Sept. pp. 393-406.Africa, South AfricaGeophysics - seismics
DS200812-1111
2008
Gohl, K.Stankiewicz, J., Parsiegla, N., Ryberg, T., Gohl, K., Weckhmann, U., Trumball, R., Weber, M.Crustal structure of the southern margin of the African continent: results from geophysical experiments.Journal of Geophysical Research, Vol. 113, B005612.AfricaGeophysics - seismics
DS200912-0731
2008
Gohl, K.Stankiewicz, J., Parsiegle, N., Ryberg, T., Gohl, K., Weckmann, U., Trumball, R., Weber, M.Crustal structure of the southern margin of the African continent: results from geophysical experiments.Journal of Geophysical Research, Vol. 113, B10, B10313AfricaTectonics
DS201212-0212
2012
Gohl, K.Funck, T., Gohl, K., Damm, V., Heyde, I.Tectonic evolution of southern Baffin Bay and Davis Strait: results from a seismic refraction transect between Canada and Greenland.Journal of Geophysical Research, Vol. 117, B04107, 24p.Canada, Nunavut, Baffin Island, Europe, GreenlandGeophysics - seismics
DS201212-0711
2012
Gohl, K.Suckro, S.K., Gohl, K., Funck, T., Heyde, I., Ehrardt, A., Schreckenberger, B., Gerlings, J., Damm, V., Jokat, W.The crustal structure of southern Baffin Bay: implications from a seismic refraction experiment.Geophysical Journal International, Vol. 190, 1, pp. 37-58.Canada, Nunavut, Baffin Island, Europe, GreenlandGeophysics - seismics
DS201312-0485
2013
Gohl, K.Kipl, A.F., Werner, R., Gohl, K., Van den Bogaard, P., Hoemle, K., Maichur, D., Klugel, A.Seamounts off the West Antarctic margin: a case for non-hotpsot driven intra-plate volcanism.Gondwana Research, Vol. 25, 4, pp. 1660-1679.AntarcticaIntra-plate volcanism
DS1995-0647
1995
Gohl. K.Gohl. K., Pederson, L.B.Collisional tectonics of the Baltic Shield in northern Gulf of Bothnia from seismic dat a BABEL projectGeophys. Journal of International, Vol. 120, No. 1, Jan. pp. 209-226.Finland, Sweden, Baltic ShieldTectonics, Geophysics -seismics
DS2003-0477
2003
Goho, A.Goho, A.The nature of things: attempts to change the periodic table raise eyebrowsScience News, Vol. 164, 17, Oct. 25, 4p.GlobalNews item - periodic table
DS200412-0683
2003
Goho, A.Goho, A.The nature of things: attempts to change the periodic table raise eyebrows.Science News, Vol. 164, 17, Oct. 25, 4p.TechnologyNews item - periodic table
DS200512-0349
2004
Goho, A.Goho, A.Experiments point to methane in Earth's mantle.Science News, Vol. 166, 13, Sept. 25, p. 198.MantleGeochemistry - methane
DS200912-0168
2009
Gokam, S.G.Dessai, A.G., Peinado, M., Gokam, S.G., Downes, H.Structure of the deep crust beneath the Central Indian Tectonic Zone: an integration of geophysical and xenolith data.Gondwana Research, Vol. 17, 1., pp. 162-170.IndiaTectonics
DS200412-0684
2004
Gokarn, S.G.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
Gokarn, S.G.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
DS201012-0152
2010
Gokarn, S.G.Dessai, A.G., Peinado, M., Gokarn, S.G., Downes, H.Structure of the deep crust beneath the Central Indian Tectonic Zone: an integration of geophysical dat a and xenolith dat a.Gondwana Research, Vol. 17, pp. 162-170.IndiaGeothermometry
DS201412-0302
2013
Gokarn, S.G.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
DS1960-0050
1960
Gokhale, K.V.G.K.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
DS201512-1920
2015
Gokhale, M.Gokhale, 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.
DS200812-0419
2008
Golabek, G.J.Golabek, G.J., Schmelling, H., Tackley, P.J.Earth's core formation aided by flow channelling instabilities induced by iron diapirs.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 24-33.MantleCore, iron
DS200912-0027
2009
Golabek, G.J.Bagdassarov, N., Solferino, G., Golabek, G.J., Schmidt, M.W.Centrifuge assisted percolation of Fe-S melts in partially molten peridotite: time constraints for planetary core formation.Earth and Planetary Science Letters, Vol. 288, 1-2, pp. 84-95.MantleMelting
DS201706-1102
2017
Golabek, G.J.Rozel, A.B., Golabek, G.J., Jain, C., Tackley, P.J., Gerya, T.Continental crust formation on early Earth controlled by intrusive magmatism.Nature, online availableMantlegeodynamics

Abstract: The global geodynamic regime of early Earth, which operated before the onset of plate tectonics, remains contentious. As geological and geochemical data suggest hotter Archean mantle temperature1, 2 and more intense juvenile magmatism than in the present-day Earth3, 4, two crust-mantle interaction modes differing in melt eruption efficiency have been proposed: the Io-like heat-pipe tectonics regime dominated by volcanism5, 6 and the “Plutonic squishy lid” tectonics regime governed by intrusive magmatism, which is thought to apply to the dynamics of Venus7, 8, 9. Both tectonics regimes are capable of producing primordial tonalite-trondhjemite-granodiorite (TTG) continental crust5, 10 but lithospheric geotherms and crust production rates as well as proportions of various TTG compositions differ greatly9, 10, which implies that the heat-pipe and Plutonic squishy lid hypotheses can be tested using natural data11. Here we investigate the creation of primordial TTG-like continental crust using self-consistent numerical models of global thermochemical convection associated with magmatic processes. We show that the volcanism-dominated heat-pipe tectonics model results in cold crustal geotherms and is not able to produce Earth-like primordial continental crust. In contrast, the Plutonic squishy lid tectonics regime dominated by intrusive magmatism results in hotter crustal geotherms and is capable of reproducing the observed proportions of various TTG rocks. Using a systematic parameter study, we show that the typical modern eruption efficiency of less than 40 per cent12 leads to the production of the expected amounts of the three main primordial crustal compositions previously reported from field data4, 11 (low-, medium- and high-pressure TTG). Our study thus suggests that the pre-plate-tectonics Archean Earth operated globally in the Plutonic squishy lid regime rather than in an Io-like heat-pipe regime.
DS2000-0743
2000
GolaniPandit, M.K., Sial, Golani, FerreiraTerrigenous and mantle contributions in Newania carbonatite body, stable isotopic constraints...Igc 30th. Brasil, Aug. abstract only 1p.India, WestCarbonatite - petrogenesis, Deposit - Newania
DS1985-0478
1985
Golani, P.R.Nambiar, A.R., Golani, P.R.A New Find of Carbonatite from MeghalayaCurrent Science., Vol. 54, No. 6, MARCH 20, PP. 281-283.India, MeghalayaBlank
DS2001-0886
2001
Golani, P.R.Pandit, M.K., Golani, P.R.Reappraisal of the petrologic status of Newania carbonatite of Rajasthan, western India.Journal of African Earth Sciences, Vol. 19, No. 3, Apr. pp.305-310.IndiaCarbonatite - petrology, Deposit - Newania
DS1985-0646
1985
Gold, BASE METALS.Sth. afr. mining, COAL, Gold, BASE METALS.Argyle- It's Full Steam Ahead for Top Diamond ProjectSth. Afr. Mining, Coal, Gold, Base Metals, Vol. No. 1, January pp. 5-13South AfricaEconomics
DS1989-0296
1989
Gold, D.Corriveau, L., Gold, D., Bedard, J., Bourne, J.Alkaline and calc-alkaline complexes of southern QuebecGeological Association of Canada (GAC) Field Trip, Trip No. B3, May 17-21, 129pQuebecKensington Pluton, Monteregian Hills, Saint Dorothea Roya, Mount Johnson, Mount Mega
DS1992-1419
1992
Gold, D.Sirkis, D., Grandstaff, D., Castro, J., Gold, D.Testing a model of diatreme emplacement at Oka, Quebec, using rockmagnetismEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 102QuebecCarbonatite, Oka
DS201704-0625
2016
Gold, D.Gold, D., Doden, A.G., Mbalu-Keswa, C., Tedeski, J.R., Mathur, R.The Rogue kimberlite dikes in Indiana County, Pennsylvania Part 1. unusual intrusive habit of kimberlite dikes in coal seams.Guidebook 81st annual field conference of Pennsylvania Geologists, Oct. 6-8, pp. 121-160.United States, PennsylvaniaDeposit - Rogue
DS201704-0626
2016
Gold, D.Gold, D., Doden, A.G., Mbalu-Keswa, C., Tedeski, J.R., Mathur, R.Supplement to guidebook: Petrography of the Tanoma and Ernest kimberlites.Guidebook 81st annual field conference of Pennsylvania Geologists, Oct. 6-8, pp. 263-268.United States, PennsylvaniaDeposit - Rogue
DS1999-0821
1999
Gold, D.G.J.Young, G.M., Von Brunn, V., Gold, D.G.J., Minter, W.E.L.Earth's oldest reported glaciation: physical and chemical evidence from the Archean Mozaan Group ( 2.9GaJournal of Geology, Vol. 106, No. 5, Sept. pp. 523-38.South AfricaGeomorphology, Kaapvaal Craton, Pongola Group
DS1995-0648
1995
Gold, D.J.C.Gold, D.J.C., Von Veh, M.W.Tectonic evolution of the Late Archean Pongola Mozaan basin, South SOURCE[ Journal of African Earth SciencesJournal of African Earth Sciences, Vol. 21, No. 2, Aug. 1, pp. 203-212South AfricaTectonics, Basin -Pongola Mozaan
DS1960-0244
1962
Gold, D.P.Gold, D.P.The Oka ComplexN.e.i.g.c. Guidebook 54th. Editor Clark, T. Mcgill University, PP. 7-14.Canada, QuebecRelated Rocks
DS1960-0349
1963
Gold, D.P.Gold, D.P.The Relationship between the Limestones and the Alkaline Rocks of Oka and St. Hilaire, Quebec.Ph.d. Thesis, Mcgill University, 354P.Canada, QuebecAlnoite, Carbonatite
DS1960-0350
1963
Gold, D.P.Gold, D.P.Average Chemical Composition of CarbonatitesEconomic Geology, Vol. 58, PP. 988-991.Canada, QuebecRelated Rocks, Analyses
DS1960-0667
1966
Gold, D.P.Gold, D.P.The Mineralogy of the Oka Carbonatite and Alkaline Complex, oka Quebec.International MIN. Association 4TH. GEN. MEETING NEW DELHI, Proceedings Vol., PP. 109-125.Canada, QuebecRelated Rocks
DS1960-0668
1966
Gold, D.P.Gold, D.P.The Average and Typical Chemical Composition of CarbonatitesFourth International Min. Association Meeting Publishing Min. Soc. of India., PP. 83-91.Canada, QuebecRelated Rocks, Analyses
DS1960-0829
1967
Gold, D.P.Gold, D.P.Alkaline Ultrabasic Rocks in the Montreal Area, QuebecIn: Ultramafic And Related Rocks, Editor Wyllie, P.j., PP. 288-302.Canada, QuebecRelated Rocks
DS1960-0830
1967
Gold, D.P.Gold, D.P., Vallee, M., Charette, J.P.Economic Geology and Geophysics of the Oka Alkaline Complex, Quebec.The Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Vol. 60, PP. 1131-1144.Canada, QuebecBlank
DS1960-0942
1968
Gold, D.P.Deines, P., Gold, D.P., Herzog, L.F.Variability of C 13 and O 18 in Carbonates from a Mica Peridotite Dike Near Dixonville.Geological Society of America (GSA) SPECIAL PAPER., No. 101, PP. 51-52.United States, Appalachia, PennsylvaniaGeochronology, Carbon
DS1960-0952
1968
Gold, D.P.Gold, D.P.Natural and Synthetic Diamonds and the North American OutlooEarth Min. Sci. Penn. State University, Vol. 37, No. 5, PP. 37-43.United States, Great LakesNatural Diamond
DS1960-1110
1969
Gold, D.P.Gold, D.P., Marchand, M.The Diatreme Breccia Pipes and Dykes and the Related Alnoite,kimberlite and Carbonatite Intrusions Occur in the Montreal Area and Oka Areas, Quebec.Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) GUIDEBOOK, GEOLOGY of THE MONTREGIAN HILLS, PP. 5-42.Canada, QuebecRelated Rocks
DS1970-0517
1972
Gold, D.P.Gold, D.P.Montregian Hills: Diatremes, Kimberlite, Lamprophyres and Intrusive Breccias West of Montreal.International Geological Congress 24TH., EXCURSION B 10 GUIDEBOOK, 32P.Canada, QuebecGeology, Classification, Ile Bizard, Ile Cadieux, la Trappe, Alnoite
DS1970-0518
1972
Gold, D.P.Gold, D.P.Montregian Hills: Ultra-alkaline Rocks and the Oka ComplexInternational Geological Congress 24TH., EXCURSION B11 GUIDEBOOK, 51P.Canada, QuebecRelated Rocks
DS1970-0663
1973
Gold, D.P.Deines, P., Gold, D.P.The isotopic composition of carbonatite and kimberlite carbonates and their bearing on isotopic composition..Geochimica Et Cosmochimica Acta, Vol. 37, pp. 1709-33.Uganda, Kenya, East African RiftGeochronology, Composition Of Deep Seated Carbon
DS1970-0695
1973
Gold, D.P.Gold, D.P.Crustal Control on the Emplacement of KimberlitesProceedings of First International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 131-134.South Africa, United StatesTectonics, Genesis
DS1975-1102
1979
Gold, D.P.Kobelski, B.J., Gold, D.P., Deines, P.Variations in Stable Isotope Compositions for Carbon and Oxygen in Some South African Kimberlites.Earth and Planetary Science Letters, Vol. 40, PP.South Africa, LesothoBenfontein, De Beers, Wesselton, Monastery, National, Premier
DS1984-0307
1984
Gold, D.P.Gold, D.P.A Diamond Exploration Philosophy for the 1980's. the RecogniEarth And Mineral Sciences, Vol. 53, No. 4, SUMMER PP. 37-42.United States, Russia, Canada, Tanzania, Lesotho, South Africa, AustraliaBrief Overview Of Exploration, Classification, Genesis, Origin
DS1985-0238
1985
Gold, D.P.Gold, D.P., Deines, P., Ulmer, G.C., Moats, M.A., Weiss, D.Types and Tectonic Settings of Diamond Bearing LamprophyresGeological Association of Canada (GAC)., Vol. 10, P. A21, (abstract.).GlobalReview
DS1986-0294
1986
Gold, D.P.Gold, D.P., Eby, G.M., Vallee, M.Carbonatites, diatremes and ultra alakaline rocks in the Okaarea, QuebecGeological Association of Canada (GAC) Field trip Guidebook, No. 21, 51pQuebecMonteregian, Aillikite, alnoite, okaite, carbonatite, ijolit, Melilite, glimmerite, Ile C.
DS1991-0585
1991
Gold, D.P.Gold, D.P.Carbonatites: an important source for space -age materialsAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, No. 91-139, 9pGlobalCarbonatite, Overview, examples
DS1992-0369
1992
Gold, D.P.Doden, A.G., Gold, D.P.Unusual carbonate rich dikes and lamprophyres in Porcupine Dome, east central MontanaGeological Society of America (GSA) Abstracts with programs, 1992 Annual, Vol. 24, No. 7, abstract p. A262MontanaLamprophyres, Carbonate
DS1993-0363
1993
Gold, D.P.Doden, A.G., Gold, D.P.Kimberlite xenocrysts from the Porcupine Dome diatremes east-centralMontana: evidence for multiple sources of garnet and evaluation of diamondpotentialGeological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A98 abstract onlyMontanaXenocrysts, Garnet
DS1994-0438
1994
Gold, D.P.Doden, A.G., Gold, D.P., Walker, R.Geochemistry of diatremes and dikes with lamprophyric/carbonatitic affinities from discrete alkalic intrusive centres in Montana.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p. PosterMontanaCarbonatite, Geochemistry
DS1994-1129
1994
Gold, D.P.Mbalu-Keswa, C., Gold, D.P., Tedeski, J.R.Inclusions in clinopyroxene xenocrysts from the Tanoma kimberlite IndianaCounty, Pennsylvania.Geological Society of America Abstracts, Vol. 26, No. 3, March, p. 60. AbstractGlobalKimberlite inclusions, Tanoma
DS1994-1130
1994
Gold, D.P.Mbalu-Keswa, C., Gold, D.P., Tedeski, J.R.Polymineralic blebs in pyroxene megacrysts from the Tonoma kimberlites, Indiana County, Pennsylvania, USAGeological Association of Canada (GAC) Abstract Volume, Vol. 19, p. PosterGlobalMegacrysts, Tonoma
DS1997-0281
1997
Gold, D.P.Doden, A.G., Gold, D.P.Origin of carbonatite minerals in ultramafic lamprophyres of CentralMontana.Geological Association of Canada (GAC) Abstracts, POSTER.MontanaCarbonatite, Lamprophyres
DS1997-0424
1997
Gold, D.P.Gold, D.P.A model of depth zones for central core carbonatitesGeological Association of Canada (GAC) Abstracts, GlobalCarbonatite
DS1984-0308
1984
Gold, J.S.Gold, J.S., Bassett, W.A., Weathers, M.S., Bird, J.M.Melting of Diamond in Shock Experiments to 150 Gpa.Science., Vol. 225, No. 4665, AUG. 31ST. PP. 921-922.GlobalDiamond Morphology, Phase Diagram
DS201807-1507
2018
Gold, R.Levandowski, W., Herrmann, R.B., Briggs, R., Boyd, O., Gold, R.An updated stress map of the continental United States reveals heterogeneous intraplate stress. TectonicsNature Geoscience, Vol. 11, 6, pp. 433-437.United Statesgeodynamics

Abstract: Knowledge of the state of stress in Earth’s crust is key to understanding the forces and processes responsible for earthquakes. Historically, low rates of natural seismicity in the central and eastern United States have complicated efforts to understand intraplate stress, but recent improvements in seismic networks and the spread of human-induced seismicity have greatly improved data coverage. Here, we compile a nationwide stress map based on formal inversions of focal mechanisms that challenges the idea that deformation in continental interiors is driven primarily by broad, uniform stress fields derived from distant plate boundaries. Despite plate-boundary compression, extension dominates roughly half of the continent, and second-order forces related to lithospheric structure appear to control extension directions. We also show that the states of stress in several active eastern United States seismic zones differ significantly from those of surrounding areas and that these anomalies cannot be explained by transient processes, suggesting that earthquakes are focused by persistent, locally derived sources of stress. Such spatially variable intraplate stress appears to justify the current, spatially variable estimates of seismic hazard. Future work to quantify sources of stress, stressing-rate magnitudes and their relationship with strain and earthquake rates could allow prospective mapping of intraplate hazard.
DS2001-0394
2001
Gold, T.Gold, T.The deep hot biosphereSpringer, 256p. $ 20.00GlobalBook - biosphere
DS2000-0266
2000
Goldberg, A.Elburg, M., Goldberg, A.Age and geochemistry of Karoo dolerite dikes from northeast BotswanaJournal of African Earth Sci., Vol. 31, No. 3-4, pp. 539-54.BotswanaGeochronology, geochemistry, Dyke swarm
DS1998-0519
1998
Goldberg, A.S.Goldberg, A.S.The Botswana dyke swarm and its relationship to the break up of GondwanaJournal of African Earth Sciences, Vol. 27, 1A, p. 89. AbstractBotswanaGondwana, Magmatism
DS201012-0239
2010
Goldberg, A.S.Goldberg, A.S.Dyke swarms as indicators of major extensional events in the 1.9 1-2 Ga Columbia supercontinent.Journal of Geodynamics, Vol. 50, 3-4, pp. 176-190.MantleCrustal evolution
DS1997-0425
1997
Goldberg, D.Goldberg, D.The role of downhole measurements in marine geology and geophysicsReviews of Geophysics, Vol. 35, No. 3, August pp. 315-342.GlobalGeophysics - seismics
DS1986-0295
1986
Goldberg, S.A.Goldberg, S.A., Butler, J.R., Fullager, P.D.The Bakersville dike swarm: geochronology and petrogenesis of late Proterozoic basaltic magmatism in the southern Appalachian Blue RidgeAmerican Journal of Science, Vol. 286, No. 5, May pp. 403-430AppalachiaDyke
DS201012-0240
2010
Goldblatt, C.Goldblatt, C., Zahnie, K.The subduction origin of mantle nitrogen.Goldschmidt 2010 abstracts, abstractMantleNitrogen
DS201509-0404
2015
Goldblatt, C.Johnson, B., Goldblatt, C.The nitrogen budget of Earth.Earth Science Reviews, Vol. 148, pp. 150-173.MantleNitrogen

Abstract: We comprehensively compile and review N content in geologic materials to calculate a new N budget for Earth. Using analyses of rocks and minerals in conjunction with N–Ar geochemistry demonstrates that the Bulk Silicate Earth (BSE) contains ~ 7 ± 4 times present atmospheric N (4 × 1018 kg N, or PAN), with 27 ± 16 × 1018 kg N. Comparison to chondritic composition, after subtracting N sequestered into the core, yields a consistent result, with BSE N between 17 ± 13 × 1018 kg to 31 ± 24 × 1018 kg N. Embedded in the chondritic comparison we calculate a N mass in Earth's core (180 ± 110 to 30 ± 180 × 1018 kg) as well as present discussion of the Moon as a proxy for the early mantle. Significantly, our study indicates that the majority of the planetary budget of N is in the solid Earth. We suggest that the N estimate here precludes the need for a “missing N” reservoir. Nitrogen–Ar systematics in mantle rocks and primary melts identify the presence of two mantle reservoirs: MORB-source like (MSL) and high-N. High-N mantle is composed of young, N-rich material subducted from the surface and identified in OIB and some xenoliths. In contrast, MSL appears to be made of old material, though a component of subducted material is evident in this reservoir as well. Taking into account N mass and isotopic character of the atmosphere and BSE, we calculate a ?15N value of ~ 2%. This value should be used when discussing bulk Earth N isotope evolution. Additionally, our work indicates that all surface N could pass through the mantle over Earth history, and in fact the mantle may act as a long-term sink for N. Since N acts as a tracer of exchange between the atmosphere, oceans, and mantle over time, clarifying its distribution in the Earth is critical for evolutionary models concerned with Earth system evolution. We suggest that N be viewed in the same light as carbon: it has a fast, biologically mediated cycle which connects it to a slow, tectonically-controlled geologic cycle.
DS201711-2519
2017
Goldblatt, C.Johnson, B.W., Goldblatt, C.A secular increase in continental crust nitrogen during the Precambrian. Glacial tillsGeochemical Perspectives Letters, Vol. 4, pp. 24-28.Mantlegeomorphology

Abstract: Recent work indicates the presence of substantial geologic nitrogen reservoirs in the mantle and continental crust. Importantly, this geologic nitrogen has exchanged between the atmosphere and the solid Earth over time. Changes in atmospheric nitrogen (i.e. atmospheric mass) have direct effects on climate and biological productivity. It is difficult to constrain, however, the evolution of the major nitrogen reservoirs through time. Here we show a secular increase in continental crust nitrogen through Earth history recorded in glacial tills (2.9 Ga to modern), which act as a proxy for average upper continental crust composition. Archean and earliest Palaeoproterozoic tills contain 66 ± 100 ppm nitrogen, whereas Neoproterozoic and Phanerozoic tills contain 290 ± 165 ppm nitrogen, whilst the isotopic composition has remained constant at ~4‰. Nitrogen has accumulated in the continental crust through time, likely sequestered from the atmosphere via biological fixation. Our findings support dynamic, non-steady state behaviour of nitrogen through time, and are consistent with net transfer of atmospheric N to geologic reservoirs over time.
DS201810-2332
2018
Goldblatt, C.Johnson, B.W., Goldblatt, C.The new Earth system nitrogen model. EarthNGeochemistry, Geophysics, Geosystems, Vol. 19, 8, pp. 2516-2542.Mantlenitrogen

Abstract: The amount of nitrogen in the atmosphere, oceans, crust, and mantle have important ramifications for Earth's biologic and geologic history. Despite this importance, the history and cycling of nitrogen in the Earth system is poorly constrained over time. For example, various models and proxies contrastingly support atmospheric mass stasis, net outgassing, or net ingassing over time. In addition, the amount available to and processing of nitrogen by organisms is intricately linked with and provides feedbacks on oxygen and nutrient cycles. To investigate the Earth system nitrogen cycle over geologic history, we have constructed a new nitrogen cycle model: EarthN. This model is driven by mantle cooling, links biologic nitrogen cycling to phosphate and oxygen, and incorporates geologic and biologic fluxes. Model output is consistent with large (2-4x) changes in atmospheric mass over time, typically indicating atmospheric drawdown and nitrogen sequestration into the mantle and continental crust. Critical controls on nitrogen distribution include mantle cooling history, weathering, and the total Bulk Silicate Earth+atmosphere nitrogen budget. Linking the nitrogen cycle to phosphorous and oxygen levels, instead of carbon as has been previously done, provides new and more dynamic insight into the history of nitrogen on the planet.
DS201511-1842
2015
Golden, J.J.Hazen, R.M., Hystad, G., Downs, R.T., Golden, J.J., Pires, A.J., Grew, E.S.Earth's missing minerals.American Mineralogist, Vol. 100, pp. 2344-2347.TechnologyMineralogy

Abstract: Recent studies of mineral diversity and distribution lead to the prediction of >1563 mineral species on Earth today that have yet to be described-approximately one fourth of the 6394 estimated total mineralogical diversity. The distribution of these "missing" minerals is not uniform with respect to their essential chemical elements. Of 15 geochemically diverse elements (Al, B, C, Cr, Cu, Mg, Na, Ni, P, S, Si, Ta, Te, U, and V), we predict that approximately 25% of the minerals of Al, B, C, Cr, P, Si, and Ta remain to be described - a percentage similar to that predicted for all minerals. Almost 35% of the minerals of Na are predicted to be undiscovered, a situation resulting from more than 50% of Na minerals being white, poorly crystallized, and/or water soluble, and thus easily overlooked. In contrast, we predict that fewer than 20% of the minerals of Cu, Mg, Ni, S, Te, U, and V remain to be discovered. In addition to the economic value of most of these elements, their minerals tend to be brightly colored and/or well crystallized, and thus likely to draw attention and interest. These disparities in percentages of undiscovered minerals reflect not only natural processes, but also sociological factors in the search, discovery, and description of mineral species.
DS201605-0844
2016
Golden, J.J.Hazen, R.M., Hummer, D.R., Hystad, G., Downs, R.T., Golden, J.J.Carbon mineral ecology: predicting the undiscovered minerals of carbon.American Mineralogist, Vol. 101, pp. 889-906.TechnologyCarbon minerals
DS201709-2035
2017
Golden, J.J.Morrison, S.M., Liu, C., Prabhu, E.A., Li, C., Downs, R.J., Golden, J.J., Fox, P., Hummer, D.R., Meyer, M.B., Hazen, R.M.Network analysis of mineralogical systems.American Mineralogist, in press availableTechnologydata sets

Abstract: A fundamental goal of mineralogy and petrology is the deep understanding of mineral phase relationships and the consequent spatial and temporal patterns of mineral coexistence in rocks, ore bodies, sediments, meteorites, and other natural polycrystalline materials. The multi-dimensional chemical complexity of such mineral assemblages has traditionally led to experimental and theoretical consideration of 2-, 3-, or n-component systems that represent simplified approximations of natural systems. Network analysis provides a dynamic, quantitative, and predictive visualization framework for employing “big data” to explore complex and otherwise hidden higher-dimensional patterns of diversity and distribution in such mineral systems. We introduce and explore applications of mineral network analysis, in which mineral species are represented by nodes, while coexistence of minerals is indicated by lines between nodes. This approach provides a dynamic visualization platform for higher-dimensional analysis of phase relationships, because topologies of equilibrium phase assemblages and pathways of mineral reaction series are embedded within the networks. Mineral networks also facilitate quantitative comparison of lithologies from different planets and moons, the analysis of coexistence patterns simultaneously among hundreds of mineral species and their localities, the exploration of varied paragenetic modes of mineral groups, and investigation of changing patterns of mineral occurrence through deep time. Mineral network analysis, furthermore, represents an effective visual approach to teaching and learning in mineralogy and petrology.
DS1989-0320
1989
Goldenberg, G.Czygan, W., Goldenberg, G.Petrography and geochemistry of the alkaline complexes of Sivamalai, Elchuru and Uppalapadu, IndiaGeological Society of India, Memoir, Editor C. LeelanandaM., No. 15, pp. 225-240IndiaAlkaline rocks, Geochemistry
DS2002-0659
2002
GoldfarbHart, C.J.R., McCoy, D.T., Goldfarb, Smith, RobertsGeology, exploration and discovery in the Tintin a gold province Alaska and YukonSociety of Economic Geologists Special Publication, No.9,pp.241-74.Yukon, AlaskaGold, Deposit - Tintina area
DS2002-0587
2002
Goldfarb, R.J.Goldfarb, R.J., Nielsen, R.L.Integrated methods for discovery: global exploration in the twenty first century.All papers cited separatelySociety of Economic Geologists, Special Paper No. 9, 380p.GlobalBook - table of contents, Overview papers
DS2002-0995
2002
Goldfarb, R.J.Marsh, E.E., Goldfarb, R.J., Day, W.C.Integrated methods for discovery: global exploration in the twenty first century.abstracts.Society of Economic Geologists, Abstract volume No. 9, 150p.GlobalBook - table of contents
DS201605-0921
2016
Goldfarb, R.J.Xie, Y., Hou, Z., Goldfarb, R.J., Guo, X., Wang, L.Rare earth element deposits in China.SEG Reviews in Economic Geology, editors Verplanck, P.L., Hitzman, M.W., No. 18, pp. 115-136.ChinaBayan Obo, Maoniuping
DS201702-0253
2016
Goldfarb, R.J.Xie, Y., Hou, Z., Goldfarb, R.J., Guo, X., Wang, L.Rare earth element deposits in China.Reviews in Economic Geology, Vol. 18, pp. 115-136.ChinaREE deposits

Abstract: China is the world’s leading rare earth element (REE) producer and hosts a variety of deposit types. Carbonatite-related REE deposits, the most significant deposit type, include two giant deposits presently being mined in China, Bayan Obo and Maoniuping, the first and third largest deposits of this type in the world, respectively. The carbonatite-related deposits host the majority of China’s REE resource and are the primary supplier of the world’s light REE. The REE-bearing clay deposits, or ion adsorption-type deposits, are second in importance and are the main source in China for heavy REE resources. Other REE resources include those within monazite or xenotime placers, beach placers, alkaline granites, pegmatites, and hydrothermal veins, as well as some additional deposit types in which REE are recovered as by-products. Carbonatite-related REE deposits in China occur along craton margins, both in rifts (e.g., Bayan Obo) and in reactivated transpressional margins (e.g., Maoniuping). They comprise those along the northern, eastern, and southern margins of the North China block, and along the western margin of the Yangtze block. Major structural features along the craton margins provide first-order controls for REE-related Proterozoic to Cenozoic carbonatite alkaline complexes; these are emplaced in continental margin rifts or strike-slip faults. The ion adsorption-type REE deposits, mainly situated in the South China block, are genetically linked to the weathering of granite and, less commonly, volcanic rocks and lamprophyres. Indosinian (early Mesozoic) and Yanshanian (late Mesozoic) granites are the most important parent rocks for these REE deposits, although Caledonian (early Paleozoic) granites are also of local importance. The primary REE enrichment is hosted in various mineral phases in the igneous rocks and, during the weathering process, the REE are released and adsorbed by clay minerals in the weathering profile. Currently, these REE-rich clays are primarily mined from open-pit operations in southern China. The complex geologic evolution of China’s Precambrian blocks, particularly the long-term subduction of ocean crust below the North and South China blocks, enabled recycling of REE-rich pelagic sediments into mantle lithosphere. This resulted in the REE-enriched nature of the mantle below the Precambrian cratons, which were reactivated and thus essentially decratonized during various tectonic episodes throughout the Proterozoic and Phanerozoic. Deep fault zones within and along the edges of the blocks, including continental rifts and strike-slip faults, provided pathways for upwelling of mantle material.
DS202006-0957
2016
Goldfarb, R.J.Xie, Y., Hou, Z., Goldfarb, R.J., Guo, X., Wang, L.Rare Earth element deposits in China.SEG Reviews In Economic Geology Chapter 6, Vol. 18, pp. 115-136.ChinaREE

Abstract: China is the world’s leading rare earth element (REE) producer and hosts a variety of deposit types. Carbonatite- related REE deposits, the most significant deposit type, include two giant deposits presently being mined in China, Bayan Obo and Maoniuping, the first and third largest deposits of this type in the world, respectively. The carbonatite-related deposits host the majority of China’s REE resource and are the primary supplier of the world’s light REE. The REE-bearing clay deposits, or ion adsorption-type deposits, are second in importance and are the main source in China for heavy REE resources. Other REE resources include those within monazite or xenotime placers, beach placers, alkaline granites, pegmatites, and hydrothermal veins, as well as some additional deposit types in which REE are recovered as by-products. Carbonatite-related REE deposits in China occur along craton margins, both in rifts (e.g., Bayan Obo) and in reactivated transpressional margins (e.g., Maoniuping). They comprise those along the northern, eastern, and southern margins of the North China block, and along the western margin of the Yangtze block. Major structural features along the craton margins provide first-order controls for REE-related Proterozoic to Cenozoic carbonatite alkaline complexes; these are emplaced in continental margin rifts or strike-slip faults. The ion adsorption-type REE deposits, mainly situated in the South China block, are genetically linked to the weathering of granite and, less commonly, volcanic rocks and lamprophyres. Indosinian (early Mesozoic) and Yanshanian (late Mesozoic) granites are the most important parent rocks for these REE deposits, although Caledonian (early Paleozoic) granites are also of local importance. The primary REE enrichment is hosted in various mineral phases in the igneous rocks and, during the weathering process, the REE are released and adsorbed by clay minerals in the weathering profile. Currently, these REE-rich clays are primarily mined from open-pit operations in southern China. The complex geologic evolution of China’s Precambrian blocks, particularly the long-term subduction of ocean crust below the North and South China blocks, enabled recycling of REE-rich pelagic sediments into mantle lithosphere. This resulted in the REE-enriched nature of the mantle below the Precambrian cratons, which were reactivated and thus essentially decratonized during various tectonic episodes throughout the Proterozoic and Phanerozoic. Deep fault zones within and along the edges of the blocks, including continental rifts and strike-slip faults, provided pathways for upwelling of mantle material.
DS200912-0254
2009
GoldFields Mineral ServicesGoldFields Mineral ServicesDiamond mine economics: production costs, margins, cash flows to 2030 - a new study from GFMS Mine Economics ... ( no price given... obviously!)GFMS, June, ?GlobalEconomics
DS1989-1239
1989
Goldhaber, M.B.Pratt, W.P., Goldhaber, M.B.United States Geological Survey (USGS) -Missouri Geological Survey Symposium: Mineral resource potential of the mid-continentUnited States Geological Survey (USGS) Open file, No. 89-169, 45pMidcontinentResource potential
DS1992-0583
1992
Goldhaber, M.B.Goldhaber, M.B., Eidel, J.J.Mineral resources of the Illinois Basin in the context of basin evolutionUnited States Geological Survey (USGS) Open File, No. 92-0001, 68p. $ 11.25Kentucky, IllinoisMineral resources, Tectonics
DS1995-1513
1995
Goldhaber, M.B.Potter, C.J., Goldhaber, M.B., Heigold, P.C., Drahovzal, J.Structure of the Reelfoot Rough Creek Rift System, Fluorspar area fault complex and Hicks Dome...United States Geological Survey (USGS) Prof. paper, No. 1538- Q, 20p.Midcontinent, Illinois, KentuckyGeophysics - seismics
DS1960-0669
1966
Goldich, S.S.Goldich, S.S., Lidiak, E.G., Hedge, C.E., Wathall, F.G.Geochronology of the Midcontinent Region, United States. Pt. 2. Northern Area.Journal of GEOPHYSICAL RESEARCH, Vol. 71, No. 22, PP. 5389-5408.GlobalMid-continent
DS1960-0670
1966
Goldich, S.S.Goldich, S.S., Muehlberger, W.R., Kidiak, E.G., Hedge, C.E.Geochronology of the Midcontinent Region, United States. Pt. 4: Eastern Area.Journal of GEOPHYSICAL RESEARCH, Vol. 71, No. 22, PP. 5375-5388.GlobalMid-continent
DS1995-0649
1995
Goldie, R.Goldie, R.Diamond Fields Resources Inc. company profile - with emphasis on nickelRichardson Greenshields Equity Research, 14p.LabradorNews item, Diamond Fields
DS201212-0250
2012
Goldie, R.Goldie, R.Diamonds and demographics.PDAC 2012, abstractGlobal, India, ChinaHistory, De Beers, economics
DS201504-0200
2015
Goldie, R.Goldie, R.Diamonds .. Nominal US dollar price for rough diamonds graphThe 2015 Commodity Price Book, p. 31 ( I pg graph)GlobalPrice index
DS202001-0013
2019
Goldie, R.Goldie, R.Approximation of Tiffany & Co. seasonally - adjusted, quarterly sales per store ( sales x $ 000). Raymondgoldie @outlook.com, Dec. 6, 1p. GraphGlobalTiffany
DS1996-0539
1996
Goldie, R.J.Goldie, R.J.The dollar: an economic geologist's most important unit of measurementThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 89, No. 997, Feb. pp. 39-41Canada, GlobalEconomics, Grades, tons, geostatistics, costs, grades in dollars
DS1994-1750
1994
GoldingTaylor, W.R., Rock, N.M.S., Groves, D.I., Perring, C.S., GoldingGeochemistry of Archean shoshonitic lamprophyres from the Yilgarn Block: gold abundance and association with gold mineralizationApplied Geochemistry, Vol. 9, pp. 197-222AustraliaAlkaline rocks -Shoshonite, Lamprophyre
DS1988-0216
1988
Golding, S.D.Finlayson, E.J., Rock, N.M.S., Golding, S.D.Deformation and regional carbonate metasomatism of turbidite hosted Cretaceous alkaline lamprophyres (northwest Papua New Guinea)Chemical Geology, Vol. 69, No. 3-4, pp. 215-233Papua New GuineaCamptonite, Lamprophyres
DS1989-1199
1989
Golding, S.D.Perring, C.S., Rock, N.M.S., Golding, S.D., Roberts, D.E.Criteria for the recognition of metamorphosed or altered lamprophyres: acase study from the Archean of Kambalda Western AustraliaPrecambrian Research, Vol. 43, nol 2, pp. 215-237AustraliaCanada, Zimbabwe, Tanzania, Classification -Lamprophy, Geochemistry
DS200812-0420
2007
Goldmacher, J.Goldmacher, J., Hoernle, K., Klugel, A., Van den Bogaard, P., Bindeman, I.Geochemistry of a new enriched mantle type locality in the northern hemisphere: implications for the origin of the EM-I source.Earth and Planetary Science Letters, Vol. 265, 1-2, pp. 167-182.MantleMetasomatism
DS1986-0288
1986
Goldman, D.Gierth, E., Goldman, D., Leonardos, O.H., Baecker, M.L.Main features of the paragenetic evolution of the Carbonatite complex of Catalao 1, GoiasBrasilIn: Symposium on Latin American Sciences, Vol. 1985 No. 9-10, pp. 1469-1475BrazilBlank
DS1989-0523
1989
Goldman, D.S.Goldman, D.S., Perfit, M.R., Ridley, W.I.Petrology and geochemistry of the Thirtynine mile volcanic field, Colorado: an intracontinental shoshonitic suiteNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 111. AbstractColoradoShoshonite
DS200912-0255
2008
Goldman, H.B.Goldman, H.B.Between a ROC and a hard place: the Republic of Congo's illict trade in diamonds and efforts to break the cycle of corruption.Thesis, University of Pennsylvania Journal of International Law, Vol. 30, 1, pp. 359-396.Africa, Democratic Republic of CongoHistory
DS200412-0139
2003
Goldman, L.Berman, P., Goldman, L.The billionaire who cracked De Beers. Lev Leviev is taking on the most successful cartel in the world.Forbes.com, Vol. 172, 5, Sept. 15, pp. 108-116.RussiaNews item - Leviev, profile
DS202204-0517
2022
Goldman, N.Chen, M., Li, C., Palumbo, G., Zhu, Y-Q., Goldman, N., Cappellaro, P.A synthetic monopole source of Kalb- Raman field in diamond.Science, Vol. 375, 6584 pp. 1017-1020.Globalgeophysics - magnetics

Abstract: Magnetic monopoles play a central role in various areas of fundamental physics, ranging from electromagnetism to topological states of matter. While their observation is elusive in high-energy physics, monopole sources of artificial gauge fields have been recently identified in synthetic matter. String theory, a potentially unifying framework that encompasses quantum mechanics, promotes the conventional \emph{vector} gauge fields of electrodynamics to \emph{tensor} gauge fields, and predicts the existence of more exotic \emph{tensor monopoles} in 4D space. Here we report on the characterization of a tensor monopole synthesized in a 4D parameter space by the spin degrees of freedom of a single solid-state defect in diamond. Using two complementary methods, we characterize the tensor monopole by measuring its quantized topological charge and its emanating Kalb-Ramond field. By introducing a fictitious external field that breaks chiral symmetry, we further observe an intriguing transition in the spectrum, characterized by spectral rings protected by mirror symmetries. Our work represents the first detection of tensor monopoles in a solid-state system and opens up the possibility of emulating exotic topological structures inspired by string theory.
DS1860-0939
1896
Goldman, S.Goldman, S., Kitchin, J.South Africa Mines; Their Position, Results and Developments: Together with an Account of Diamonds, Land, Finance and Kindred Concerns. Goldman's South African Mines and Finance.Johannesburg: Argus Publishing, THREE VOLUMES, Vol. 1, RAND MINING COMPANIES; Vol. 2Africa, South AfricaCompany Histories Listing Of Directors, Capital And General
DS1982-0223
1982
Goldman, S.Goldman, S.Ge Develops Process to Brand Codes in DiamondsNational Jeweler., Vol. 26, No. 9, PP. 41-42.GlobalDiamond Identification
DS201909-2022
2019
Goldmann, S.Benaouda, R., Kraemer, D., Sitnikova, M., Goldmann, S., Freitag, R., Bouali, A., Mouttaqi, A., El Haloui, R., Essaadaoui, M., Bau, M.Thorium-poor monazite and columbite-(Fe) mineralization in the Gleibat Lafhouda carbonatite and its associated iron-oxide-apatite deposit of the Ouled Dlim Massif, South Morocco.Gondwana Research, Vol. 77, pp. 19-39.Africa, MoroccoREE

Abstract: Recent exploration work in South Morocco revealed the occurrence of several carbonatite bodies, including the Paleoproterozoic Gleibat Lafhouda magnesiocarbonatite and its associated iron oxide mineralization, recognized here as iron-oxide-apatite (IOA) deposit type. The Gleibat Lafhouda intrusion is hosted by Archean gneiss and schist and not visibly associated with alkaline rocks. Metasomatized micaceous rocks occur locally at the margins of the carbonatite outcrop and were identified as glimmerite fenite type. Rare earth element (REE) and Nb mineralization is mainly linked to the associated IOA mineralization and is represented by monazite-(Ce) and columbite-(Fe) as major ore minerals. The IOA mineralization mainly consists of magnetite and hematite that usually contain large apatite crystals, quartz and some dolomite. Monazite-(Ce) is closely associated with fluorapatite and occurs as inclusions within the altered parts of apatite and along cracks or as separate phases near apatite. Monazite shows no zonation patterns and very low Th contents (<0.4?wt%), which would be beneficial for commercial extraction of the REE and which indicates monazite formation from apatite as a result of hydrothermal volatile-rich fluids. Similar monazite-apatite mineralization and chemistry also occurs at depth within the carbonatite, although the outcropping carbonatite is barren, suggesting an irregular REE ore distribution within the carbonatite body. The barren carbonatite contains some tiny unidentified secondary Nb-Ta-U phases, synchysite and monazite. Niobium mineralization is commonly represented by anhedral minerals of columbite-(Fe) which occur closely associated with magnetite-hematite and host up to 78?wt% Nb2O5, 7?wt% Ta2O5 and 1.6?wt% Sc2O3. This association may suggest that columbite-(Fe) precipitated by an interaction of Nb-rich fluids with pre-existing Fe-rich minerals or as pseudomorphs after pre-existing Nb minerals like pyrochlore. Our results most strongly suggest that the studied mineralization is economically important and warrants both, further research and exploration with the ultimate goal of mineral extraction.
DS201911-2511
2019
Goldmann, S.Benaouda, R., Kraemer, D., Sitnikova, M., Goldmann, S., Bau, M.Thorium poor monzonite and columbite (Fe) mineralization in the Giebat Lafhouda carbonatite and its associated iron-oxide deposit of the Ouled Dlim Massif, south Morocco.Gondwana Research, Vol. 77, pp. 19-39.Africa, Moroccocarbonatite

Abstract: Recent exploration work in South Morocco revealed the occurrence of several carbonatite bodies, including the Paleoproterozoic Gleibat Lafhouda magnesiocarbonatite and its associated iron oxide mineralization, recognized here as iron-oxide-apatite (IOA) deposit type. The Gleibat Lafhouda intrusion is hosted by Archean gneiss and schist and not visibly associated with alkaline rocks. Metasomatized micaceous rocks occur locally at the margins of the carbonatite outcrop and were identified as glimmerite fenite type. Rare earth element (REE) and Nb mineralization is mainly linked to the associated IOA mineralization and is represented by monazite-(Ce) and columbite-(Fe) as major ore minerals. The IOA mineralization mainly consists of magnetite and hematite that usually contain large apatite crystals, quartz and some dolomite. Monazite-(Ce) is closely associated with fluorapatite and occurs as inclusions within the altered parts of apatite and along cracks or as separate phases near apatite. Monazite shows no zonation patterns and very low Th contents (<0.4?wt%), which would be beneficial for commercial extraction of the REE and which indicates monazite formation from apatite as a result of hydrothermal volatile-rich fluids. Similar monazite-apatite mineralization and chemistry also occurs at depth within the carbonatite, although the outcropping carbonatite is barren, suggesting an irregular REE ore distribution within the carbonatite body. The barren carbonatite contains some tiny unidentified secondary Nb-Ta-U phases, synchysite and monazite. Niobium mineralization is commonly represented by anhedral minerals of columbite-(Fe) which occur closely associated with magnetite-hematite and host up to 78?wt% Nb2O5, 7?wt% Ta2O5 and 1.6?wt% Sc2O3. This association may suggest that columbite-(Fe) precipitated by an interaction of Nb-rich fluids with pre-existing Fe-rich minerals or as pseudomorphs after pre-existing Nb minerals like pyrochlore. Our results most strongly suggest that the studied mineralization is economically important and warrants both, further research and exploration with the ultimate goal of mineral extraction.
DS202008-1369
2020
Goldmann, S.Benoaouda, R., Kraemer, D., Sitnikova, M., Goldmann, S., Schwarz-Schampera, U., Errami, A., Mouttaqi, A., Bau, M.Discovery of high grade REE-Nb-Fe mineralization associated with calcio-carbonatite in south Morocco.Ore Geology Reviews, in press available, 43p. PdfAfrica, Moroccocarbonatite

Abstract: The recently discovered REE and Nb mineralization in the Twihinat area in the western part of the Oulad Dlim Massif (Adrar Souttouf) in South Morocco is linked to a Cretaceous calciocarbonatite intrusion which was likely formed in an intracontinental rift setting and crops out locally within a ring structure that mainly consists of massive Fe-oxide mineralization and silica breccia. The carbonatite shows intensively metasomatized zones, which contain bastnaesite and pyrochlore-group minerals as the main REE and Nb ore minerals. They are usually associated with apatite, quartz and Fe-oxides, or trapped in calcite voids, suggesting a secondary ore formation. Within the associated Fe-oxide mineralization, pyrochlore and monazite-(Ce) are the main ore minerals occurring closely associated with quartz and magnetite or hematite. The silica breccia also shows significant subsequent infill of barite, bastnaesite-(Ce) and hydrated ceriopyrochlore, which was identified by EPMA and Raman spectroscopy. Bastnaesite commonly forms prismatic aggregates whereas pyrochlore and ceriopyrochlore usually display subhedral grains along tiny fractures. Structural and textural relationships clearly indicate epigenetic ore formation induced by multiple stages of hydrothermal fluid flow and fracturing. Ore precipitation likely resulted from interaction between low-pH mineralizing hydrothermal fluids and the wall-rock. The latter efficiently buffered the acidity of the fluids and allowed significant amounts of REE and Nb ore minerals to precipitate. Trace element ICP-MS analyses show very high REE and Nb concentrations of up to 0.76 wt% ?REE and 0.21 wt% Nb in carbonatite and up to 3 wt% ?REE and 1.3 wt% Nb in the associated silica and Fe-oxide mineralization. The results clearly demonstrate that the Twihinat REE-Nb deposits are significant and represent a potential new high-grade resource for these critical metals.
DS202109-1489
2021
Goldmann, S.Sitnikova, M.A., Do Cabo, V., Wall, F., Goldmann, S.Burbankite and pseudomorphs from the main intrusion calcite carbonatite, Lofdal, Namibia: association, mineral composition, Raman spectroscopy.Mineralogical Magazine, Vol. 85, 4, pp. 496-513.Africa, Namibiadeposit - Lofdal

Abstract: The Neoproterozoic Lofdal alkaline carbonatite complex consists of a swarm of carbonatite dykes and two plugs of calcite carbonatite known as the ‘Main’ and ‘Emanya’ carbonatite intrusions, with associated dykes and plugs of phonolite, syenite, rare gabbro, anorthosite and quartz-feldspar porphyry. In the unaltered Main Intrusion calcite carbonatite the principal rare-earth host is burbankite. As burbankite typically forms in a magmatic environment, close to the carbohydrothermal transition, this has considerable petrogenetic significance. Compositional and textural features of Lofdal calcite carbonatites indicate that burbankite formed syngenetically with the host calcite at the magmatic stage of carbonatite evolution. The early crystallisation of burbankite provides evidence that the carbonatitic magma was enriched in Na, Sr, Ba and light rare earth elements. In common with other carbonatites, the Lofdal burbankite was variably affected by alteration to produce a complex secondary mineral assemblage. Different stages of burbankite alteration are observed, from completely fresh blebs and hexagonal crystals through to complete pseudomorphs, consisting of carbocernaite, ancylite, cordylite, strontianite, celestine, parisite and baryte. Although most research and exploration at Lofdal has focused on xenotime-bearing carbonatite dykes and wall-rock alteration, this complex also contains a more typical calcite carbonatite enriched in light rare earth elements and their alteration products.
DS1910-0181
1911
Goldschmidt, V.Fersmann, A. Von, Goldschmidt, V.Der Diamant. Eine StudieHeidelberg: C. Winter., 274P.GlobalCrystallography
DS201012-0241
2010
Goldschmidt ConferenceGoldschmidt ConferenceSession on UHP including Dabie, Sulu, North Qaidam areas.Goldschmidt 2010 abstracts, abstractChinaUHP
DS2002-0588
2002
Goldsmith, T.Goldsmith, T.Resources and reserves - their impact on financial reporting, valuations and the expectations gap.Australian Institute of Mining and Metallurgy, No. 3/2002, pp.21-25.AustraliaMineral reserves - definitions, measurement, performanc
DS1989-0524
1989
Goldstein, A.G.Goldstein, A.G.Tectonic significance of multiple motions on terrane bounding faults in the northern AppalachiansGeological Society of America (GSA) Bulletin, Vol. 101, No. 7, July pp. 927-938AppalachiaTectonics, Faults-Terranes
DS200812-0421
2008
Goldstein, F.Goldstein, F.An introduction to beneficiation.IDI The Israeli Diamond Industry newsletter, Feb. 7p.GlobalReview - pipeline
DS1992-0584
1992
Goldstein, J.I.Goldstein, J.I., et al.Scanning electron microscopy and X-ray microanalysis. a text forbiologists, ,material scientists and geologistsPlenum Press, second edition, 800pGlobalscanning electron microscope (SEM)., Book -table of contents first three pages
DS1960-0671
1966
Goldstein, N.E.Goldstein, N.E., Ward, S.H.The Separation of Remanent from Induced Magnetism in SituGeophysics, Vol. 31, No. 4, PP. 779-796.United States, Rocky Mountains, West Coast, NevadaKimberlite, Geophysics, Desert Eagle, Sage, Jackrabbit
DS2001-0395
2001
Goldstein, R.H.Goldstein, R.H.Paleoenvironment: clues from fluid inclusionsScience, No. 5544, Nov. 2, pp. 1009-10.MantleFluid inclusions - not specific to diamonds
DS1998-1352
1998
Goldstein, S.Simonetti, A., Goldstein, S., Schmidberger, S. Vladkar.Geochemical and neodymium, lead, and Strontium isotope dat a from Deccan alkaline complexes -inferences for mantle sources...Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 1847-64.IndiaAlkaline rocks - geochemistry, geochronology, Lithosphere - plume
DS200612-0762
2006
Goldstein, S.Langmuir, C., Goldstein, S.Recycled eclogite as the fertile component of the depleted MORB source.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 3. abstract only.MantleEclogite
DS201705-0889
2017
Goldstein, S.Weiss, Y., Goldstein, S., Class, C., Winckler, G.A billion years of metasomatic alteration of the Kaapvaal SCLM encapsulated in fribrous diamonds.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 11122 AbstractAfrica, South AfricaDeposit - De Beers-pool, Finsch
DS200812-0422
2008
Goldstein, S.B.Goldstein, S.B., Francis, D.The petrogenesis and mantle source of Archean ferropicrite from the Western Superior Province, Ontario, Canada.Journal of Petrology, Vol. 49, 10, pp. 1729-1753.Canada, Ontario, ManitobaPicrite
DS1988-0257
1988
Goldstein, S.L.Goldstein, S.L.Decoupled evolution of neodymium and Strontium isotopes in the continental crust and the mantleNature, Vol. 336, No. 6201, Dec. 22-29, pp. 733-737GlobalCrust, mantle, Geochronology
DS1989-0038
1989
Goldstein, S.L.Arndt, N.T., Goldstein, S.L.An open boundary between lower continental crust andmantle: its role incrust formation and crustalrecyclingTectonophysics, Vol. 161, No. 3/4, pp. 201-212GlobalMantle, Tectonic regimes
DS1990-1278
1990
Goldstein, S.L.Rudnick, R.L., Goldstein, S.L.The lead isotopic compositions of lower crustal xenoliths and the Evolution of lower crustal leadEarth and Planetary Science Letters, Vol. 98, pp. 192-207Australia, West GermanyGeochronology, Crustal xenoliths, Craton
DS1993-0260
1993
Goldstein, S.L.Class, C., Goldstein, S.L., Galer, S.J.G.Young formation age of a mantle plume sourceNature, Vol. 362, No. 6422, April 22, pp. 715-721MantleHot spot, Plume, Geochronology
DS1994-1195
1994
Goldstein, S.L.Miller, D.M., Goldstein, S.L., Langmuir, C.H.Cerium/lead and lead isotope ratios in arc magmas and the enrichment of lead in the continentsNature, Vol. 368, No. 6471, April 7, p. 514MantleGeochronology, Arc magmas
DS1995-0299
1995
Goldstein, S.L.Chauvel, C., Goldstein, S.L., Hofmann, A.W.Hydration and dehydration of oceanic crust controls lead evolution in themantle.Chemical Geology, Vol. 126, pp. 65-75.MantleGeochronology
DS1997-1046
1997
Goldstein, S.L.Simonetti, A., Goldstein, S.L., Schmidberger, S.S.New isotope dat a from Deccan related alkaline igneous complexes India-inferences on mantle sourcesGeological Association of Canada (GAC) Abstracts, India, west centralAlkaline rocks
DS1998-1479
1998
Goldstein, S.L.Toulkeridis, T., Goldstein, S.L., Schidlowski, M.Samarium-neodymium, Rubidium-Strontium,and lead-lead dating of silicic carbonates from early Archean Barberton greenstone belt: evidence..Precambrian Research, Vol. 92, No. 2, Oct.l, pp. 129-44South AfricaGeochronology - post depositional resetting, Low temperature
DS200412-0469
2004
Goldstein, S.L.Donnelly,K.E., Goldstein, S.L., Langmuir, C.H., Spiegelman, M.Origin of enriched ocean ridge basalts and implications for mantle dynamics.Earth and Planetary Science Letters, Vol. 226, 3-4, Oct. 15, pp. 347-366.MantleE-MORB, geochemistry, isotope, trace, convective mixing
DS200512-0169
2005
Goldstein, S.L.Class, C., Goldstein, S.L.Evolution of helium isotopes in the Earth's mantle.Nature, No. 7054, Aug. 25, pp. 1107-1112.MantleHelium
DS200512-0170
2005
Goldstein, S.L.Class, C., Goldstein, S.L.Evolution of helium isotopes in the Earth's mantle.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantleMantle plume, geochronology
DS200712-0446
2007
Goldstein, S.L.Hofmann, A.W., Goldstein, S.L., Class, C.Is D' a low mu reservoir?Plates, Plumes, and Paradigms, 1p. abstract p. A410.MantleMelting
DS200812-1310
2008
Goldstein, S.L.Zhang, H-F., Goldstein, S.L., Zhou, X-H., Sun, M., Zheng, J-P., Cai, Y.Evolution of subcontinental lithospheric mantle beneath eastern China: Re-Os isotopic evidence from mantle xenoliths in Paleozoic kimberlites and Mesozoic basaltsContributions to Mineralogy and Petrology, Vol. 155, pp. 271-293.ChinaGeochronology
DS200912-0852
2009
Goldstein, S.L.Zhang, H.F., Goldstein, S.L., Zhou, X.H., Sun, M., Cai, Y.Comprehensive refertilization of lithospheric mantle beneath the North Chin a Craton: further Os Sr Nd isotopic constraints.Journal of the Geological Society, Vol. 166, 2, pp. 249-260.ChinaGeochronology
DS201610-1917
2016
Goldstein, S.L.Weiss, Y., Class, C., Goldstein, S.L., Hanyu, T.Key new pieces of the HIMU puzzle from olivines and diamond inclusions.Nature, On line Sept. 5, 11p.MantleMelting

Abstract: Mantle melting, which leads to the formation of oceanic and continental crust, together with crust recycling through plate tectonics, are the primary processes that drive the chemical differentiation of the silicate Earth. The present-day mantle, as sampled by oceanic basalts, shows large chemical and isotopic variability bounded by a few end-member compositions1. Among these, the HIMU end-member (having a high U/Pb ratio, ?) has been generally considered to represent subducted/recycled basaltic oceanic crust2, 3, 4, 5. However, this concept has been challenged by recent studies of the mantle source of HIMU magmas. For example, analyses of olivine phenocrysts in HIMU lavas indicate derivation from the partial melting of peridotite, rather than from the pyroxenitic remnants of recycled oceanic basalt6. Here we report data that elucidate the source of these lavas: high-precision trace-element analyses of olivine phenocrysts point to peridotite that has been metasomatized by carbonatite fluids. Moreover, similarities in the trace-element patterns of carbonatitic melt inclusions in diamonds7 and HIMU lavas indicate that the metasomatism occurred in the subcontinental lithospheric mantle, fused to the base of the continental crust and isolated from mantle convection. Taking into account evidence from sulfur isotope data8 for Archean to early Proterozoic surface material in the deep HIMU mantle source, a multi-stage evolution is revealed for the HIMU end-member, spanning more than half of Earth’s history. Before entrainment in the convecting mantle, storage in a boundary layer, upwelling as a mantle plume and partial melting to become ocean island basalt, the HIMU source formed as Archean-early Proterozoic subduction-related carbonatite-metasomatized subcontinental lithospheric mantle.
DS201610-1918
2016
Goldstein, S.L.Weiss, Y., Class, C., Goldstein, S.L., Hanyu, T.Some islands started in diamond bearing regions under continents, geochemists say. Precis of Nature ref.Ideo.Columbia.edu, On line Sept. 5, 3p.MantleHIMU

Abstract: The raw materials of some volcanic islands are shaped by some of the same processes that form diamonds deep under the continents, according to a new study. The study asserts that material from diamond-forming regions journeys nearly to Earth's core and back up to form such islands, a process that could take two and a half billion years or longer -- more than half of Earth's entire history.
DS201803-0485
2018
Goldstein, S.L.Wang, D., Wang, X-L., Cai, Y., Goldstein, S.L., Yang, T.Do Hf isotopes in magmatic zircons represent those of their host rocks?Journal of Asian Earth Sciences, Vol. 154, pp. 202-212.Mantlezircons

Abstract: Lu-Hf isotopic system in zircon is a powerful and widely used geochemical tracer in studying petrogenesis of magmatic rocks and crustal evolution, assuming that zircon Hf isotopes can represent initial Hf isotopes of their parental whole rock. However, this assumption may not always be valid. Disequilibrium partial melting of continental crust would preferentially melt out non-zircon minerals with high time-integrated Lu/Hf ratios and generate partial melts with Hf isotope compositions that are more radiogenic than those of its magma source. Dissolution experiments (with hotplate, bomb and sintering procedures) of zircon-bearing samples demonstrate this disequilibrium effect where partial dissolution yielded variable and more radiogenic Hf isotope compositions than fully dissolved samples. A case study from the Neoproterozoic Jiuling batholith in southern China shows that about half of the investigated samples show decoupled Hf isotopes between zircons and the bulk rocks. This decoupling could reflect complex and prolonged magmatic processes, such as crustal assimilation, magma mixing, and disequilibrium melting, which are consistent with the wide temperature spectrum from ?630?°C to ?900?°C by Ti-in-zircon thermometer. We suggest that magmatic zircons may only record the Hf isotopic composition of their surrounding melt during crystallization and it is uncertain whether their Hf isotopic compositions can represent the primary Hf isotopic compositions of the bulk magmas. In this regard, using zircon Hf isotopic compositions to trace crustal evolution may be biased since most of these could be originally from disequilibrium partial melts.
DS201805-0992
2018
Goldstein, S.L.Weiss, Y., Navon, O., Goldstein, S.L., Harris, J.W.Inclusions in diamonds constrain thermo-chemical conditions during Mesozoic metasomatism of the Kaapvaal cratonic mantle.Earth Planetary Science Letters, Vol. 491, pp. 134-147.Africa, South Africadeposit - De Beers-Pool

Abstract: Fluid/melt inclusions in diamonds, which were encapsulated during a metasomatic event and over a short period of time, are isolated from their surrounding mantle, offering the opportunity to constrain changes in the sub-continental lithospheric mantle (SCLM) that occurred during individual thermo-chemical events, as well as the composition of the fluids involved and their sources. We have analyzed a suite of 8 microinclusion-bearing diamonds from the Group I De Beers Pool kimberlites, South Africa, using FTIR, EPMA and LA-ICP-MS. Seven of the diamonds trapped incompatible-element-enriched saline high density fluids (HDFs), carry peridotitic mineral microinclusions, and substitutional nitrogen almost exclusively in A-centers. This low-aggregation state of nitrogen indicates a short mantle residence times and/or low mantle ambient temperature for these diamonds. A short residence time is favored because, elevated thermal conditions prevailed in the South African lithosphere during and following the Karoo flood basalt volcanism at ?180 Ma, thus the saline metasomatism must have occurred close to the time of kimberlite eruptions at ?85 Ma. Another diamond encapsulated incompatible-element-enriched silicic HDFs and has 25% of its nitrogen content residing in B-centers, implying formation during an earlier and different metasomatic event that likely relates to the Karoo magmatism at ca. 180 Ma. Thermometry of mineral microinclusions in the diamonds carrying saline HDFs, based on Mg-Fe exchange between garnet-orthopyroxene (Opx)/clinopyroxene (Cpx)/olivine and the Opx-Cpx thermometer, yield temperatures between 875-1080?°C at 5 GPa. These temperatures overlap with conditions recorded by touching inclusion pairs in diamonds from the De Beers Pool kimberlites, which represent the mantle ambient conditions just before eruption, and are altogether lower by 150-250?°C compared to P-T gradients recorded by peridotite xenoliths from the same locality. Oxygen fugacity differs as well. The calculated for the saline HDF compositions (to ?1.34) are higher by about a log unit compared with that recorded by xenoliths at 4-7 GPa. We conclude that enriched saline HDFs mediated the metasomatism that preceded Group I kimberlite eruptions in the southwestern Kaapvaal craton, and that their ‘cold and oxidized’ nature reflects their derivation from a deep subducting slab. This event had little impact on the temperature and redox state of the Kaapvaal lithosphere as a reservoir, however, it likely affected its properties along limited metasomatized veins and their wall rock. To reconcile the temperature and oxygen fugacity discrepancy between inclusions in diamonds and xenoliths, we argue that xenoliths did not equilibrate during the last saline metasomatic event or kimberlite eruption. Thus the P-T-gradients they record express pre-existing lithospheric conditions that were likely established during the last major thermal event in the Kaapvaal craton (i.e. the Karoo magmatism at ca. 180 Ma).
DS201808-1796
2018
Goldstein, S.L.Weiss, Y., Goldstein, S.L.The involvement of diamond forming fluids in the metasomatic 'cocktail' of kimberlite sources.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0613-8 19p.Africa, South Africadeposit - Finsch

Abstract: Microinclusion-bearing diamonds offer the opportunity to investigate relationships between mantle metasomatism, diamond formation and kimberlite eruptions in intracratonic provinces. We have analyzed a suite of 7 microinclusion-bearing diamonds from the Finsch Group II kimberlite, South Africa, and identified two diamond populations: ‘Finsch IaA’ diamonds have nitrogen solely in A-centers and contain saline high-density-fluid (HDF) microinclusions, while ‘Finsch IaAB’ diamonds have nitrogen in both A- and B-centers (25-35% B-centers) and are characterized by carbonatite HDF compositions. Based on nitrogen aggregation states and estimates for mantle residence temperatures, we conclude that ‘Finsch IaA’ diamonds formed during a young saline metasomatic event that preceded kimberlite eruption by ~50 kyr to 15 Myr. The possible timing of metasomatism and formation of ‘Finsch IaAB’ diamonds by carbonatite HDFs is less constrained, and could have taken place between ~15 Myr and 2 Gyr before eruption. Two of the diamonds encapsulated omphacite microinclusions in association with saline or low-Mg carbonatitic-like HDF. We observe compositional differences for Al2O3 vs. CaO between these metasomatised omphacites, and also compared to omphacites in mantle eclogites which were identified as metasomatised by kimberlite or high-Mg carbonatite; suggesting a possible relationship between Al2O3 and CaO in metasomatised omphacite and the type of fluid/melt it interacted with. The combined data for microinclusion-bearing diamonds from the Finsch Group II kimberlite and the neighbouring Group I kimberlites at Koffiefontein and De Beers Pool indicate that a substantial volume of the southwest Kaapvaal deep lithosphere was impacted by saline metasomatism during Cretaceous time, and a direct relationship between saline metasomatism, diamond formation and the Kaapvaal late-Mesozoic ‘kimberlite bloom’. We therefore conclude that saline HDFs play a key role in the buildup of metasomatic mantle sources leading to kimberlite eruptions.
DS201809-2112
2018
Goldstein, S.L.Weiss,Y., Navon, O.., Goldstein, S.L., Harris, J.W.Inclusions in diamonds constrain thermo-chemical conditions of the Kaapvaal cratonic mantle.Goldschmidt Conference, 1p. AbstractAfrica, South Africadeposit - De Beers Pool

Abstract: Mineral and fluid/melt inclusions in diamonds, which are encapsulated and isolated during a metasomatic event, offer the opportunity to constrain changes in the sub-continental lithospheric mantle that occurred during individual thermochemical events. Fibrous diamonds from the Group I De Beers Pool kimberlites, South Africa (SA), trapped incompatibleelement enriched saline high-density fluids (HDFs) and peridotitic mineral microinclusions. Their substitutional nitrogen resides almost exclusively in A-centers. With regard to the elevated thermal conditions that prevailed in the SA lithosphere during and following Karoo volcanism at ~180 Ma, this low-aggregation state of nitrogen suggests a short mantle residence time, constraining the time of saline metasomatism to be close to the eruption of the kimberlites at ~85 Ma. Thermometry of mineral microinclusions yield temperatures between 875-1080 ºC (at 5 GPa). These temperatures overlap with conditions recorded by touching inclusion pairs, which represent the mantle ambient conditions just before eruption, and are altogether lower by 150-250°C compared to P-T gradients recorded by peridotite xenoliths from the same locality. In addition, the oxygen fugacity calculated for the saline HDF compositions (?log??O2(FMQ) = -2.5 to -1.3) are higher by about a log unit compared with that recorded by xenoliths at 4-7 GPa. We conclude that enriched saline HDFs mediated the metasomatism that preceded Group I kimberlite eruptions in the southwestern Kaapvaal craton, and that their ‘cold and oxidized’ nature reflects their derivation from a deep subducting slab. To reconcile the temperature and oxygen fugacity discrepancy between inclusions in diamonds and xenoliths, we argue that xenoliths did not equilibrate during the last saline metasomatic event or kimberlite eruption. Thus the P-T-??O2 gradients they record express pre-existing lithospheric conditions that were likely established during the last major thermal event in the Kaapvaal craton (i.e. the Karoo magmatism at ca. 180 Ma).
DS202106-0976
2021
Goldstein, S.L.Weiss, Y., Kiro, Y., Class, C., Winckler, G., Harris, J.W., Goldstein, S.L.Helium in diamonds unravels over a billion years of craton metasomatism. KaapvaalNature Communications, Vol. 12, 2667, 11p. PdfAfrica, South Africageochronology

Abstract: Chemical events involving deep carbon- and water-rich fluids impact the continental lithosphere over its history. Diamonds are a by-product of such episodic fluid infiltrations, and entrapment of these fluids as microinclusions in lithospheric diamonds provide unique opportunities to investigate their nature. However, until now, direct constraints on the timing of such events have not been available. Here we report three alteration events in the southwest Kaapvaal lithosphere using U-Th-He geochronology of fluid-bearing diamonds, and constrain the upper limit of He diffusivity (to D???1.8?×?10?19 cm2 s?1), thus providing a means to directly place both upper and lower age limits on these alteration episodes. The youngest, during the Cretaceous, involved highly saline fluids, indicating a relationship with late-Mesozoic kimberlite eruptions. Remnants of two preceding events, by a Paleozoic silicic fluid and a Proterozoic carbonatitic fluid, are also encapsulated in Kaapvaal diamonds and are likely coeval with major surface tectonic events (e.g. the Damara and Namaqua-Natal orogenies).
DS1991-1177
1991
Goldstein, W.Mohnen, V.A., Goldstein, W., Wei-Chyung WangThe conflict over global warming -the application of scientific research to policy choicesGlobal Environmental Change, March pp. 109-123United StatesGlobal warming, Climate
DS1991-1178
1991
Goldstein, W.Mohnen, V.A., Goldstein, W., Wei-Chyung WangThe conflict over global warming -the application of scientific research topolicy choicesGlobal Environmental Change, March pp. 109-123United StatesGlobal warming, Climate
DS1994-0633
1994
Goldstrand, P.M.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
DS1988-0258
1988
Goldthwait, R.P.Goldthwait, R.P., Matsch, C.L.Genetic classification of glacigenic deposits. Finalreport on genesis and lithology of glacial quartern.deposits of the International Union for QuaternaryResearchBalkema, 294p. $ 65.00GlobalGeomorphology, Table of contents filed
DS1992-0585
1992
Goldthwaite, R.P.Goldthwaite, R.P.Historical overview of Early Wisconsin glcaiationGeological Society of America, Special Paper No. 270, pp. 13-18WisconsinGeomorphology, Glacial deposits
DS1988-0305
1988
Gole, M.J.Hill, R.E.T., Gole, M.J., Barnes, S.J.Physical volcanology of komatiites. a field guide to the komatiites between Kalgoorlie and Wiluna, Eastern Gold fields Province, Yilgarn Block, WesternAustraliaGsa Western Australia Excursion Guidebook, No. 1, 74pAustraliaGuidebook, Komatiites
DS1995-0801
1995
Gole, M.J.Hill, R.E.T., Barnes, S.J., Gole, M.J., Dowling, S.E.The volcanology of komatiites as deduced from field relationships in the Norseman-Wiluna greenstone beltLithos, Vol. 34, No. 1-3, Jan. pp. 159-188AustraliaKomatiites, Norseman greenstone belt
DS1996-0540
1996
Goleby, B.Goleby, B., et al.The Mount Isa geodynamic transect... deep seismic reflection profile south of Mount Isa and CloncurryAgso Research Newsletter, No. 24, May pp. 6-12AustraliaGeophysics -seismics, Deposit -Mount Isa area
DS1998-0160
1998
Goleby, B.Braun, J., Dooley, J., Goleby, B., Van der Hilst et al.Structure and evolution of the Australian continentAmerican Geophysical Union (AGU) Geodynamic Series, Vol. 26, 186p. app. $ 42.00AustraliaMantle - lithosphere, structure, Tectonics
DS2002-0589
2002
Goleby, B.Goleby, B.Major structures for gold in seismic images of crustAusgeo News, December, pp. 26-27.AustraliaGeophysics - seismics, Crustal thickness, geometry Yilgarn
DS1989-0525
1989
Goleby, B.R.Goleby, B.R., Shaw, R.D., Wright, C., Kennett, B.L.N., Lambeck, K.Geophysical evidence for thick skinned crustal deformation incentralAustraliaNature, Vol. 337, No. 6205, January 26, pp. 325-330AustraliaGeophysics, Tectonics
DS1993-0377
1993
Goleby, B.R.Drummond, B.J., Goleby, B.R., Swager, C.P., Williams, P.R.Constraints on Archean crustal composition and structure provided by deep seismic sounding in the Yilgarn blockOre Geology Reviews, Vol. 8, pp. 117-124AustraliaGeophysics, Kalgoorlie Terrane, Callion Terrane
DS1994-0634
1994
Goleby, B.R.Goleby, B.R., Drummond, B.J., Korsch, R.J., et al.Review of recent results from continental deep seismic profiling inAustraliaTectonophysics, Vol. 232, 1-4, pp. 1-12AustraliaGeophysics -seismics, Profiles
DS1998-0792
1998
Goleby, B.R.Korsch, R.J., Goleby, B.R., Drummond, B.J.Crustal architecture of central Australia based on deep seismic reflectionprofiling.Tectonophysics, Vol. 288, No. 1-4, Mar. pp. 57-70.Australia, Central AustraliaTectonics, Geophysics - seismic
DS2000-0245
2000
Goleby, B.R.Drummond, B.J., Goleby, B.R., Sawger, C.P.Crustal signature of Late Archean tectonic episodes in the Yilgarn Craton:evidence from deep seismic soundingTectonophysics, Vol. 329, No. 1-4, Dec. 31, pp. 193-222.AustraliaGeophysics - seismics, Tectonics - craton
DS200512-0350
2004
Goleby, B.R.Goleby, B.R., Blewett, R.S., Korsch, R.J., Champion, D.C., Cassidy, K.F., Jones, L.E., Groenewald, P.B., Henson, P.Deep seismic reflection profiling in the Archean northeastern Yilgarn Craton: implications for crustal architecture and mineral potential.Tectonophysics, Vol. 388, 1-4, pp. 119-133.AustraliaGeophysics - seismics, not specific to diamonds
DS200612-0404
2006
Goleby, B.R.Fomin, T., Goleby, B.R.Lessons from a joint interpretation of vibroseis wide angle and near vertical reflection dat a in the northeastern Yilgarn, Western Australia.Tectonophysics, in pressAustraliaCraton, Geophysics - seismics, wide-angle reflection
DS200612-1465
2005
Goleby, B.R.Van der Velden, A.J., Cook, F.A., Drummond, B.J., Goleby, B.R.Reflections of the Neoarchean: a global perspective.Benn, K., Mareschal, J-C., Condie, K.C. Archean Geodynamics and Environments, AGU Geophysical Monograph, No. 164, pp. 255-266.MantleGeophysics - seismsics
DS1985-0119
1985
Golikova, E.V.Chernobe, YM., Kuchuk, V.I., Klochkov, O.V., Golikova, E.V.Influence of Temperature on the Coagulation of Natural Diamond Suspensions.Colloid Journal, Vol. 47, No. 2, MAR-APRIL PP. 361-362.RussiaBlank
DS1985-0373
1985
Golikova, E.V.Kuchuk, V.I., Golikova, E.V., Chernoberezhakii, YU.M.Potentiometric Titration of a Natural Diamond MicropowderColloid Journal, Vol. 46, No. 6, PP. 982-987.GlobalDiamond Properties
DS2001-0755
2001
GollaMcEnroe, S.A., Harrison, R.J., Robinson, P., GollaEffect of fine scale microstructures in titanohematite on the acquisition and stability of natural remnant...Journal of Geophysical Research, Vol. 106, No. 12, pp. 30,523-46.SwedenCrustal magnetism
DS200712-0902
2006
Golla-Schindler, U.Rohrbach, A., Ballhaus, C., Golla-Schindler, U., Ulmer, P.Ferric ferrous iron ratios in upper mantle minerals.Geochimica et Cosmochimica Acta, In press availableMantleChemistry - iron
DS200712-0903
2007
Golla-Schindler, U.Rohrbach, A., Ballhaus, C., Golla-Schindler, U., Ulmer, P., Kamenetsky, V.S., Kuzmin, D.V.Metal saturation in the upper mantle.Nature, Vol. 449, no. 7161, Sept. 27, pp.456-458.MantleOxygen fugacity
DS200712-0904
2007
Golla-Schindler, U.Rohrbach, A., Ballhaus, C., Golla-Schindler, U., Ulmer, P., Schonbohm, D.Metal saturation in the upper mantle.Plates, Plumes, and Paradigms, 1p. abstract p. A848.MantleOxygen fugacities
DS201112-0876
2011
Golla-Schindler, U.Rohrbach, A., Ballhaus, C., Ulmer, P., Golla-Schindler, U., Schnbohm, D.Experimental evidence for a reduced metal saturated upper mantle.Journal of Petrology, Vol. 52, 4, pp. 717-737.MantleRedox
DS201212-0251
2012
Golle, O.Golle, O., Dumoulin, C., Choblet, G., Cadek, O.Topography and geoid induced by a convecting mantle beneath an elastic lithosphere.Geophysical Journal International, in press availableMantleConvection
DS1997-0310
1997
Golledge, R.G.Egenhofer, M.I., Golledge, R.G.Spatial and temporal reasoning in geographic information systemsOxford, 320p. approx. $ 60.00GlobalBook - ad, GIS systems
DS1992-0743
1992
Golmshtok, A.J.Hutchinson, D.R., Golmshtok, A.J., Zonenshain, L.P., et al.Depositional and tectonic framework of the rift basins of Lake Baikal from multichannel seismic dataGeology, Vol. 20, No. 7, July pp. 589-592RussiaRifting, Lake Baikal and East African Rift system
DS202111-1772
2021
Gololobova, A.G.Legostaeva, Y.R., Gololobova, A.G.Long-term geochemical monitoring of the soil cover in the impact zone of diamond mining enterprises: a case study in the Nakyn kimberlite field, Russia.Environmental Monitoring Assessment, Vol. 193, 337, 6p. PdfRussiadeposit - Nakyn

Abstract: The most severe disturbance of the earth’s surface occurs when the open-cut method of mineral deposits mining is used. The geoecological situation was assessed based on the nature of the soil cover based on the example of an industrial site of a diamond mining and processing plant located in the permafrost zone. During the period from 2007 to 2018, the soil cover of the industrial site is characterized by polyelement contamination. In the surface, soil horizons were an increase in the concentrations of mobile forms of Mn, Zn, Cd, Cr, Co, and Ni. It is identified that AO, ABcr, and CR are the accumulation horizons if the soil profile is preserved. Mobile forms Mn, Zn, Ni, Cr, Co, and As can migrate along with the soil profile to a depth of 40-50 cm depending on the amount of soil organic matter, the degree of its decomposition, and the scale of the cryoturbation. Research in 2018 allowed us to localize and confirm the increase in the area of contamination of the industrial site. Areas with an extremely dangerous category of soil cover contamination increased by 3 times compared to 2014. The results obtained are the basis for a more detailed study of the horizons of geochemical accumulation and the creation of artificial geochemical barriers with the development of technologies for the subsequent extraction of useful components.
DS2002-0590
2002
Golonka, J.Golonka, J.Plate tectonic maps of the PhanerozoicSepm, No. 72, pp. 21-76.GlobalMaps - tectonic, text
DS1994-1339
1994
Golovano, T.I.Parsadanyan, K.S., Golovano, T.I.Typomorphic features of phlogopite as an indicator of nature of ultramafic rocks from Arkhangelsk region. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 334, No. 1, January pp. 87-89.Russia, Yakutia, ArkangelskPetrography, Ultramafic -phlogopite
DS2003-0171
2003
Golovanova, I.Brown, D., Carbonell, R., Kukkonen, I., Ayala, C., Golovanova, I.Composition of the Uralide crust from seismic velocity ( Vp Vs) heat flow , gravity andEarth and Planetary Science Letters, Vol. 210, 1-2, pp. 333-49.Russia, UralsGeophysics
DS200412-0222
2003
Golovanova, I.Brown, D., Carbonell, R., Kukkonen, I., Ayala, C., Golovanova, I.Composition of the Uralide crust from seismic velocity ( Vp Vs) heat flow , gravity and magnetic data.Earth and Planetary Science Letters, Vol. 210, 1-2, pp. 333-49.Russia, UralsGeophysics
DS1996-1070
1996
Golovanova, T.I.Parsadanyan, K.S., Golovanova, T.I.Type features of phlogopite as indicators of the nature of the Arkhangel region ultramafites.Doklady Academy of Sciences, Vol. 334, pp. 107-111.Russia, ArkangelskPetrology, Deposit -Anonaliya 697, Zvezdochka
DS200812-0537
2008
GolovinKamenetsky, M.B., Kamenenetsky, V.S., Sobolev, A.V., Golovin, Sharygin, Demouchy, Faure, KuzminOlivine in the Udachnaya East kimberlite ( Yakutia, Russia): morphology, compositional zoning and origin.9IKC.com, 3p. extended abstractRussiaDeposit - Udachnaya petrograaphy
DS201112-0640
2011
GolovinMalkovets, V.G., Zedgenizov, Sobolev, Kuzmin, Gibsher, Shchukina, Golovin, Verichev, PokhilenkoContents of trace elements in olivines from diamonds and peridotite xenoliths of the V.Grib kimberlite pipe ( Arkhangel'sk Diamondiferous province, Russia).Doklady Earth Sciences, Vol. 436, 2, pp. 301-307.RussiaDeposit - Grib
DS201012-0309
2010
Golovin, A.Ionov, D.A., Doucet, L., Golovin, A., Ashchepkov, I.Can cratonic mantle be formed in subduction related settings?Goldschmidt 2010 abstracts, AbstractMantleSubduction
DS201412-0795
2014
Golovin, A.Sharygin, I., Litasov, K., Shatskiy, A., Golovin, A., Ohtani, E., Pokhilenko, N.Is kimberlite magma ascent fuelled by CO2 degassing via orthopyroxene assimilation?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. AbstractTechnologyModel
DS201412-0796
2014
Golovin, A.Sharygin, I., Litasov, K., Shatskiy, A., Golovin, A., Ohtani, E., Pokhilenko, N.Melting phase relations of the Udachnaya East Group 1 kimberlite at 3.0-6.5 GPA: experimental evidence for alkali-carbonatite composition of primary kimberlite melt.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-East
DS201707-1339
2017
Golovin, A.Kitayama, Y., Thomassot, E., Galy, A., Golovin, A., Korsakov, A., d'Eyrames, E., Assayag, N., Bouden, N., Ionov, D.Co-magmatic sulfides and sulfates in the Udachnaya-East pipe ( Siberia): a record of the redox state and isotopic composition of sulfur in kimberlites and their mantle sources.Chemical Geology, Vol. 455, pp. 315-330.Russiadeposit - Udachnaya East

Abstract: Kimberlites of the Udachnaya-East pipe (Siberia) include a uniquely dry and serpentine-free rock type with anomalously high contents of chlorine (Cl ? 6.1 wt%), alkalies (Na2O + K2O ? 10 wt%) and sulfur (S ? 0.50 wt%), referred to as a “salty” kimberlite. The straightforward interpretation is that the Na-, K-, Cl- and S-rich components originate directly from a carbonate-chloride kimberlitic magma that is anhydrous and alkali-rich. However, because brines and evaporites are present on the Siberian craton, previous studies proposed that the kimberlitic magma was contaminated by the assimilation of salt-rich crustal rocks. To clarify the origin of high Cl, alkalies and S in this unusual kimberlite, here we determine its sulfur speciation and isotopic composition and compare it to that of non-salty kimberlites and kimberlitic breccia from the same pipe, as well as potential contamination sources (hydrothermal sulfides and sulfates, country-rock sediment and brine collected in the area). The average ?34S of sulfides is ? 1.4 ± 2.2‰ in the salty kimberlite, 2.1 ± 2.7‰ in the non-salty kimberlites and 14.2 ± 5.8‰ in the breccia. The average ?34S of sulfates in the salty kimberlites is 11.1 ± 1.8‰ and 27.3 ± 1.6‰ in the breccia. In contrast, the ?34S of potential contaminants range from 20 to 42‰ for hydrothermal sulfides, from 16 to 34‰ for hydrothermal sulfates, 34‰ for a country-rock sediment (Chukuck suite) and the regional brine aquifer. Our isotope analyses show that (1) in the salty kimberlites, neither sulfates nor sulfides can be simply explained by brine infiltration, hydrothermal alteration or the assimilation of known salt-rich country rocks and instead, we propose that they are late magmatic phases; (2) in the non-salty kimberlite and breccia, brine infiltration lead to sulfate reduction and the formation of secondary sulfides – this explains the removal of salts, alkali-carbonates and sulfates, as well as the minor olivine serpentinization; (3) hydrothermal sulfur was added to the kimberlitic breccia, but not to the massive kimberlites. In situ measurements of sulfides confirm this scenario, clearly showing the addition of two sulfide populations in the breccia (pyrite-pyrrhotites with average ?34S of 7.9 ± 3.4‰ and chalcopyrites with average ?34S of 38.0 ± 0.4‰) whereas the salty and non-salty kimberlites preserve a unique population of djerfisherites (Cl- and K-rich sulfides) with ?34S values within the mantle range. This study provides the first direct evidence of alkaline igneous rocks in which magmatic sulfate is more abundant than sulfide. Although sulfates have been rarely reported in mantle materials, sulfate-rich melts may be more common in the mantle than previously thought and could balance the sulfur isotope budget of Earth's mantle.
DS201710-2224
2017
Golovin, A.d'Eyrames, E., Thomassot, E., Kitayama, Y., Golovin, A., Korsakov, A., Ionov, D.A mantle origin for sulfates in the unusual "salty" Udachnaya-East kimberlite from sulfur abundances, speciation and their relationship with groundmass carbonates.Bulletin de la Societe Geologique de France *eng, Vol. 188, 1-2, 8p.Russia, Siberiadeposit - Udachnaya-East

Abstract: The Udachnaya-East pipe in Yakutia in Siberia hosts a unique dry (serpentine-free) body of hypabyssal kimberlite (<0.64wt% H2O), associated with a less dry type of kimberlite and a serpentinized kimberlitic breccia. The dry kimberlite is anomalously rich in salts (Na2O and Cl both up to 6wt%) whereas the slightly less dry and the breccia kimberlite are salt free. Yet the Udachnaya kimberlite is a group-I kimberlite, as is the archetypical kimberlite from Kimberley, South Africa. Samples were studied from the three different types of kimberlite (dry-salty, n=8, non-salty, n=5 and breccia, n=3) regarding their mineralogy, geochemistry, and more specifically their sulfur content. Our results show the salty kimberlite is unprecedentedly rich in sulfur (0.13-0.57wt%) compared to the non-salty kimberlite (0.04-0.12wt%) and the breccia (0.29-0.33wt%). In the salty kimberlite, most of the sulfur is present as sulfates (up to 97% of Stotal) and is disseminated throughout the groundmass in close association with Na-K-bearing carbonates. Sulfates occur within the crystal structure of these Na-K-bearing carbonates as the replacement of (CO3) by (SO3) groups, or as Na- and K-rich sulfates (e.g. aphtitalite, (K,Na)3Na(SO4)2). The associated sulfides are djerfisherite; also Na- and K-rich species. The close association of sulfates and carbonates in these S-rich alkaline rocks suggests that the sulfates crystallized from a mantle-derived magma, a case that has strong implication for the oxygen fugacity of kimberlite magmatism and more generally for the global S budget of the mantle.
DS201710-2259
2017
Golovin, A.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.
DS202006-0937
2020
Golovin, 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.
DS202108-1266
2021
Golovin, A.Abersteiner, A., Kamenetsky, V.S., Golovin, A., Goemann, K., Ehrig, K.Dissolution of mantle orthopyroxene in kimberlitic melts: petrographic, geochemical and melt inclusion constraints from an orthopyroxenite xenolith from the Udachnaya-East kimberlite ( Siberian Craton, Russia).Lithos, Vol. 398-399, 17p. PdfRussia, Siberiadeposit - Udachnaya-East

Abstract: Reconstructing the original composition of kimberlite melts in the mantle and delineating the processes that modify them during magmatic ascent and emplacement in the crust remains a significant challenge in kimberlite petrology. One of the most significant processes commonly cited to drive initial kimberlite melts towards more Si-Mg-rich compositions and decrease the solubility of CO2 is the assimilation of mantle orthopyroxene. However, there is limited direct evidence to show the types of reactions that may occur between mantle orthopyroxene and the host kimberlite melt. To provide new constraints on the interaction between orthopyroxene and parental kimberlite melts, we examined a fresh (i.e. unmodified by secondary/post-magmatic alteration) orthopyroxenite xenolith, which was recovered from the serpentine-free units of the Udachnaya-East kimberlite (Siberian Craton, Russia). This xenolith is composed largely of orthopyroxene (~ 90%), along with lesser olivine and clinopyroxene and rare aluminous magnesian chromite. We can show that this xenolith was invaded by the host kimberlite melt along grain interstices and fractures, where it partially reacted with orthopyroxene along the grain boundaries and replaced it with aggregates of compositionally distinct clinopyroxene, olivine and phlogopite, along with subordinate Fe-Cr-Mg spinel, Fesingle bondNi sulphides and djerfisherite (K6(Fe,Ni,Cu)25S26Cl). Primary melt inclusions in clinopyroxene replacing xenolith-forming orthopyroxene, as well as secondary melt inclusion trails in xenolith orthopyroxene, clinopyroxene and olivine are composed of similar daughter mineral assemblages that consist largely of: Nasingle bondK chlorides, along with varying proportions of phlogopite, Fe-Cu-Ni sulphides, djerfisherite, rasvumite (KFe2S3), Cr-Fe-Mg spinel, nepheline and apatite, and rare rutile, sodalite, barite, olivine, Ca-K-Na carbonates and Nasingle bondK sulphates. The melt entrapped by these inclusions likely represent the hybrid products produced by the invading kimberlite melt reacting with orthopyroxene in the xenolith. The mechanism that could explain the partial replacement of orthopyroxene in this xenolith by clinopyroxene, olivine and phlogopite could be attributed to the following reaction: Orthopyroxene + Carbonatitic (melt) ? Olivine + Clinopyroxene + Phlogopite + CO2. This reaction is supported by theoretical and experimental studies that advocate the dissolution of mantle orthopyroxene within an initially silica-poor and carbonate-rich kimberlite melt. The mineral assemblages replacing orthopyroxene in the xenolith, together with hosted melt inclusions, suggests that the kimberlitic melt prior to reaction with orthopyroxene was likely carbonate-rich and Na-K-Cl-S bearing. The paucity of carbonate in the reaction zones around orthopyroxene and in melt inclusions in clinopyroxene replacing xenolith-forming orthopyroxene and xenolith minerals (orthopyroxene, clinopyroxene and olivine) is attributed to the consumption of carbonates and subsequent exsolution of CO2 by the proposed decarbonation reaction. Concluding, we propose that this orthopyroxenite xenolith provides a rare example of the types of reactions that can occur between mantle orthopyroxene and the host kimberlite melt. The preservation of this xenolith and zones around orthopyroxene present new insights into the composition and evolution of parental kimberlite melts and CO2 exsolution.
DS1998-1325
1998
Golovin, A.V.Sharygin, V.V., Golovin, A.V., Smirnov, S.Z., MalkovetsRelationships between websterite xenolith and host basanite ( Pipe BeleKhakasia, Russia)... silicate melt7th International Kimberlite Conference Abstract, pp. 788-790.RussiaXenolith, Deposit - Bele pipe
DS2000-0344
2000
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Malkovets, V.G.Evolution of melt during crystallization of the Bele pipe basanites. North Minusa depression.Russian Geology and Geophysics, Vol.41,12,pp.1710-31., Vol.41,12,pp.1710-31.RussiaBasanite
DS2000-0345
2000
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Malkovets, V.G.Evolution of melt during crystallization of the Bele pipe basanites. North Minusa depression.Russian Geology and Geophysics, Vol.41,12,pp.1710-31., Vol.41,12,pp.1710-31.RussiaBasanite
DS2002-0591
2002
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Pokhilenko, N.P., Malkovets, V.G., KoelsovSecondary melt inclusions in olivine from unaltered kimberlites of the Udachnaya East pipe, Yakutia.Doklady Earth Sciences, Vol. 388,1,pp. 93-96.Russia, YakutiaPetrology, deposit - Udachnaya
DS2003-0478
2003
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Pkhilenko, N.P., Malkovets, V.G., Kolesov, B.A.Secondary melt inclusions in olivine from unaltered kimberlites of the Udachnaya EastDoklady Earth Sciences, Russia, YakutiaBlank
DS2003-0479
2003
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Pokhilenko, N.P., Malkovets, V.G., KolesavSecondary melt inclusions in olivine from unaltered kimberlites of the Udachnaya EastDoklady Earth Sciences, Vol. 388,1, pp. 93-96.Russia, YakutiaInclusions, Deposit - Udachnaya
DS2003-0480
2003
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Pokhilenko, N.P., Malkovets, V.G., Sobolev, N.V.Secondary melt inclusions in olivine from unaltered kimberlites of the Udachnaya8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractRussia, YakutiaDeposit - Udachnaya
DS2003-1258
2003
Golovin, A.V.Sharygin, V.V., Golovin, A.V., Pokhilenko, N.P.Djerfisherite from unaltered kimberlites of the Udachnaya eastern pipe, Yakutia8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractRussia, YakutiaDeposit - Udachnaya
DS2003-1259
2003
Golovin, A.V.Sharygin, V.V., Golovin, A.V., Pokhilenko, N.P., Sobolev, N.V.Djerfisherite in unaltered kimberlites of the Udachnaya East pipe, YakutiaDoklay Earth Sciences, Vol. 390, 4, May-June pp. 554-8.RussiaMineralogy, Deposit - Udachnaya
DS200412-0685
2003
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Pkhilenko, N.P., Malkovets, V.G., Kolesov, B.A., Sobolev, N.V.Secondary melt inclusions in olivine from unaltered kimberlites of the Udachnaya East pipe, Yakutia.Doklady Earth Sciences, Vol. 388, 1, pp. 93-96.Russia, YakutiaGeochemistry - mineral chemistry
DS200412-0686
2003
Golovin, A.V.Golovin, A.V., Sharygin, V.V., Pokhilenko, N.P., Malkovets, V.G., Sobolev, N.V.Secondary melt inclusions in olivine from unaltered kimberlites of the Udachnaya eastern pipe, Yakutia.8 IKC Program, Session 7, POSTER abstractRussia, YakutiaKimberlite petrogenesis Deposit - Udachnaya
DS200412-1797
2003
Golovin, A.V.Sharygin, V.V., Golovin, A.V., Pokhilenko, N.P.Djerfisherite from unaltered kimberlites of the Udachnaya eastern pipe, Yakutia.8 IKC Program, Session 7, POSTER abstractRussia, YakutiaKimberlite petrogenesis Deposit - Udachnaya
DS200412-1798
2003
Golovin, A.V.Sharygin, V.V., Golovin, A.V., Pokhilenko, N.P., Sobolev, N.V.Djerfisherite in unaltered kimberlites of the Udachnaya East pipe, Yakutia.Doklady Earth Sciences, Vol. 390, 4, May-June pp. 554-8.RussiaMineralogy Deposit - Udachnaya
DS200512-0966
2004
Golovin, A.V.Sharygin, V.V., Golovin, A.V., Pokhilenko, N.P.Genesis of djerfisherite from kimberlites and xenoliths of the Udachnaya diatreme, Yakutia Russia.Deep seated magmatism, its sources and their relation to plume processes., pp. 236-256.RussiaMineralogy
DS200612-1428
2006
Golovin, A.V.Timina, T.Yu., Sharygin, V.V., Golovin, A.V.Melt evolution during the crystallization of basanites of the Tergesh pipe.Geochemistry International, Vol. 44, 8, pp. 752-770.RussiaBasanites, Foidites
DS200712-0366
2007
Golovin, A.V.Golovin, A.V., Shatgin, V.V.Petrogenetic analysis of fluid and melt inclusions in minerals from mantle xenoliths from the Bele pipe basanites.Russian Geology and Geophysics, Vol. 48, pp. 811-824.RussiaXenolith - petrology
DS200712-0504
2006
Golovin, A.V.Kamenetsky, V.S., Kamenetsky, M.B., Sharygin, V.V., Faure, K., Golovin, A.V.Chloride and carbonate immiscible liquids at the closure of the kimberlite magma evolution ( Udachnaya-East kimberlite, Siberia).Chemical Geology, Available in press,Russia, SiberiaDeposit - Udachnaya, geochronology
DS200712-0505
2007
Golovin, A.V.Kamenetsky, V.S., Kamenetsky, M.B., Sharygin, V.V., Golovin, A.V.Carbonate chloride enrichment in fresh kimberlites of the Udachnaya East pipe, Siberia: a clue to physical properties of kimberlite magmas?Geophysical Research Letters, Vol. 34, 9, May 16, L09316RussiaDeposit - Udachnaya
DS200712-0506
2007
Golovin, A.V.Kamenetsky, V.S., Kamenetsky, M.B., Sharygin, V.V., Golovin, A.V.Carbonate chloride enrichment in fresh kimberlites of the Udachnaya East pipe, Siberia: a clue to physical properties of kimberlite magmas?Geophysical Research Letters, Vol. 34, 9, May 16, L09316RussiaDeposit - Udachnaya
DS200712-0507
2007
Golovin, A.V.Kamenetsky, V.S., Kamenetsky, M.B., Shaygin, V.V., Faure, K., Golovin, A.V.Chloride and carbonate immiscible liquids at the closure of the kimberlite magma evolution ( Udachnaya-East kimberlite) Siberia.Chemical Geology, Vol. 237m 3-4, March 5, pp. 384-400.Russia, SiberiaDeposit - Udachnaya
DS200812-0423
2008
Golovin, A.V.Golovin, A.V., Kamenetsky, M.B., Kamenetsky, V.S., Sharygin, V.V., Pokhilenko, N.P.Groundmass of unaltered kimberlites of the Udachnaya East pipe (Yakutia Russia): a sample of the kimberlite melt.9IKC.com, 3p. extended abstractRussiaDeposit - Udachnaya
DS200812-0538
2008
Golovin, A.V.Kamenetsky, M.B., Kamenetsky, V.S, Sobolev, A.V., Golovin, A.V.Can pyroxenes be liquidus minerals in the kimberlite magma?9IKC.com, 3p. extended abstractRussiaDeposit - Udachnaya
DS200812-0539
2008
Golovin, A.V.Kamenetsky, V.S., Kamenetsky, M.B., Golovin, A.V., Maas, R., Sharygin, V.V., Pokhilenko, N.P.Salty kimberlite of the Udachnaya East pipe ( Yakutia, Russia): a petrological oddity, victim of contamination or a new magma type?9IKC.com, 3p. extended abstractRussiaDeposit - Udachnaya - taste!
DS200812-0541
2008
Golovin, A.V.Kamenetsky, V.S., Kamentsky, M.B., Sobolev, A.V., Golovin, A.V., Demouchy, S., Faure, Sharygin, KuzminOlivine in the Udachnaya east kimberlite ( Yakutia, Russia): types, compositions and origins.Journal of Petrology, Vol. 49, 4, pp. 823-839.Russia, YakutiaDeposit - Udachnaya
DS200812-1044
2008
Golovin, A.V.Sharygin, V.V., Kamenetsky, V.S., Kamenetsky, M.B., Golovin, A.V.Mineralogy and genesis of kimberlite hosted chloride containing nodules from Udachnaya East pipe, Yakutia, Russia.9IKC.com, 3p. extended abstractRussiaDeposit - Udachnaya
DS200912-0352
2009
Golovin, A.V.Kamenetsky, V.S., Mass, R., Kamenetsky, M.B., Paton, C., Phillips, D., Golovin, A.V., Gornova, M.A.Chlorine from the mantle: magmatic halides in the Udachnaya-East kimberlite, Siberia.Earth and Planetary Science Letters, Vol. 285, pp. 96-104.Russia, SiberiaDeposit - Udachnaya
DS201012-0005
2010
Golovin, A.V.Agashev, A.M., Pokhilenko, N.P., Cherepanova, Yu.V., Golovin, A.V.Geochemical evolution of rocks at the base of the lithospheric mantle: evidence from study of xenoliths of deformed peridotites from kimberlite of UdachnayaDoklady Earth Sciences, Vol. 432, 2, pp. 746-749.RussiaDeposit - Udachnaya
DS201012-0335
2009
Golovin, A.V.Kamenetsky, V.S., Kamenetsky, M.B., Sobolev, A.V., Golovin, A.V., Sharyginb, V.V., Pokhilenko, N.P., Sobolev, N.V.Can pyroxenes be liquidus minerals in the kimberlite magma?Lithos, Vol. 112 S pp. 213-235.MantleChemistry
DS201112-0063
2011
Golovin, A.V.Bascou, J., Doucet, L.S., Saumet, S., Ionov, D.A., Ashchepkov, I.V., Golovin, A.V.Seismic velocities, anisotropy and deformation in Siberian cratonic mantle: EBSD dat a on xenoliths from the Udachnaya kimberlite.Earth and Planetary Science Letters, Vol. 304, 1-2, pp. 71-84.RussiaDeposit - Udachnaya
DS201112-0287
2011
Golovin, A.V.Doucet, L.S., Ionov, D.A., Carlson, R.W., Golovin, A.V., Ashchepkov, I.V.Os isotope and PGE dat a on the age and evolution of lithospheric mantle in the central Siberian Craton.Goldschmidt Conference 2011, abstract p.777.RussiaUdachnaya kimberlite
DS201112-0465
2011
Golovin, A.V.Ionov, D.A., Doucet, L.S., Carlson, R.W., Pokhilenko, N.P., Golovin, A.V., Ashchepkov, I.V.Peridotite xenolith inferences on the formation and evolution of the central Siberian cratonic mantle.Goldschmidt Conference 2011, abstract p.1085.Russia, SiberiaUdachnaya
DS201112-0495
2011
Golovin, A.V.Kamenetsky, V.S., Mass, R., Kamenetsky, M.B., Paton, C., Phillips, D., Golovin, A.V.Chlorine from the mantle: magmatic halides in the Udachnaya East kimberlite, Siberia.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 132-149.Russia, SiberiaModel magma compositions
DS201112-0543
2011
Golovin, A.V.Korsakov, A.V., Golovin, A.V., Dieing, T., Toporski, J.Fluid inclusions in rock forming minerals of ultrahigh pressure metamorphic rocks ( Kokchetav massif, northern Kazakhstan).Doklady Earth Sciences, Vol. 437, 2, pp. 473-478.Russia, KazakhstanUHP
DS201112-0808
2011
Golovin, A.V.Pokilanko, L.N., Golovin, A.V., Shrygin, I.S., Pokhilenko, N.P.Accessory minerals of mantle xenoliths: first finds of Cl-free K-Fe sulphides.Doklady Earth Sciences, Vol. 440, 2, pp. 1404-1409.MantleXenolith petrology
DS201112-0942
2011
Golovin, A.V.Sharygin, I.S., Golovin, A.V., Pokhilenko, N.P.Djerfisherite in kimberlites of the Kuoikskoe field as an indicator of enrichment of kimberlite melts in chlorine.Doklady Earth Sciences, Vol. 436, 2, pp. 219-223.RussiaPetrology
DS201212-0005
2012
Golovin, A.V.Agashev, A.M., Ionov, D.A., Pokhilenko, N.P., Golovin, A.V., Surgutonova, E.A., Sharygin, I.S.Metasomatism in cratonic mantle root: insight from geochemistry of deformed peridotite xenoliths of Udachnaya pipe.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Udachnaya
DS201212-0252
2012
Golovin, A.V.Golovin, A.V., Sherygin, I.S., Korsakov, A.V., Pokhilenko, N.P.Can be parental kimberlite melts alkali-carbonate liquids: results investigations composition melt inclusions in mantle xenoliths from kimberlites.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractMantleMelting
DS201212-0347
2012
Golovin, A.V.Kamenetsky, V.S., Kamenetsky, M.B., Golovin, A.V., Shaygin, V.V., Maas, R.Ultrafresh salty kimberlite of the Udachnaya-East pipe ( Yakutia, Russia): a petrological oddity or fortuitous discovery?Lithos, Vol. 152, pp. 173-186.RussiaDeposit - Udachnaya-East
DS201212-0562
2012
Golovin, A.V.Pokhilenko, N.P., Afanasev, V.P., McDonald, J.A., Vavilov, M.A., Kulgin, S.S., Pokhilenko, L.N., Golovin, A.V., Agashev, A.M.Kimberlite indicator minerals in terrigene sediments of lower part of Mackenzie River Basin, NWT, Canada: evidence of new craton with thick lithosphere.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Northwest TerritoriesGeochemistry - KIMS
DS201212-0636
2012
Golovin, A.V.Sharygin, I.S., Golovin, A.V., Pokhilenko, N.P.Djerfisherite in xenoliths of sheared peridotite in the Udachanaya East pipe ( Yakutia): origin and relationship with kimberlitic magmatism.Russian Geology and Geophysics, Vol. 53, 3, pp. 247-261.Russia, YakutiaDeposit - Udachnaya
DS201212-0637
2012
Golovin, A.V.Sharygin, I.S., Golovin, A.V., Pokhilenko, N.P.Djerfisherite in kimberlite - hosted mantle xenoliths: textural features, composition and origin.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussiaDeposit - Udachnaya East
DS201212-0638
2012
Golovin, A.V.Sharygin, I.S., Litasov, K.D., Shatskiy, A., Golovin, A.V., Ohtani, E., Pokhilenko, N.P.Melting phase relations of chlorine bearing kimberlite at 2.1-6.5 GPA and 900-1500 ON10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractMantleMelting
DS201212-0802
2012
Golovin, A.V.Yaxley, G.M., Berry, A.J., Kamenetsky, V.S., Woodland, A.B., Golovin, A.V.An oxygen fugacity profile through the Siberian craton - Fe K-edge XANES determinations of Fe3 Fe in garnets in peridotite xenoliths from the Udachnaya East kimberlite.Lithos, in press availableRussia, SiberiaDeposit - Udachnaya
DS201312-0010
2013
Golovin, A.V.Agashev, A.M., Ionov, D.A., Pkhilenko, N.P., Golovin, A.V., Cherepanova, Yu., Sharygin, I.S.Metasomatism in lithospheric mantle roots: constraints from whole rock and mineral chemical composition of deformed peridotite xenoliths from kimberlite pipe Udachnaya.Lithos, Vol. 160-161, pp. 201-215.Mantle, Russia, SiberiaDeposit - Udachnaya
DS201312-0136
2013
Golovin, A.V.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
DS201312-0226
2013
Golovin, A.V.Doucet, L.S., Ionov, D.A., Golovin, A.V.The origin of coarse garnet peridotites in cratonic lithosphere: new dat a on xenoliths from the Udachnaya kimberlite, central Siberia.Contributions to Mineralogy and Petrology, Vol. 165, pp. 1225-1242.Russia, SiberiaDeposit - Udachnaya
DS201312-0429
2013
Golovin, A.V.Ionov, D.A., Doucet, L.S., Golovin, A.V.The origin of garnet peridotites in the Siberian cratonic mantle from chemical, modal and textural data.Goldschmidt 2013, AbstractRussia, SiberiaDeposit - Udachnaya
DS201312-0803
2013
Golovin, A.V.Sharygin, I.S., Litasov, K.D., Shatskiy, A., Golovin, A.V., Ohtani, E., Pokhilenko, N.P.Melting phase relations in Udachnaya-East kimberlite and search for parental melt composition. Group IGoldschmidt 2013, AbstractRussiaDeposit - Udachnaya
DS201412-0205
2014
Golovin, A.V.Doucet, L.S., Ionov, D.A., Golovin, A.V.Paleoproterozoic formation age for the Siberian cratonic mantle: Hf and Nd isotope dat a on refractory peridotite xenoliths from the Udachnaya kimberlite.Chemical Geology, Vol. 391, pp. 42-55.RussiaDeposit - Udachnaya
DS201412-0208
2014
Golovin, A.V.Doucet, L.S., Peslier, A.H., Ionov, D.A., Brandon, A.D., Golovin, A.V., Goncharov, A.G., Ashchepkov, I.V.High water contents in the Siberian cratonic mantle linked to metasomatism: an FTIR study of Udachnaya peridotite xenoliths.Geochimica et Cosmochimica Acta, in press availableRussia, SiberiaDeposit - Udachnaya
DS201412-0439
2014
Golovin, A.V.Kamenetsky, V.S., Golovin, A.V., Maas, R., Giuliani, A., Kamenetsky, M.B., Weiss, Y.Towards a new model for kimberlite petrogenesis: evidence from unaltered kimberlites and mantle minerals. Earth Science Reviews, Vol. 139, pp. 145-151.Russia, YakutiaDeposit - Udachnaya
DS201412-0797
2013
Golovin, A.V.Sharygin, I.S., Golovin, A.V., Korsakov, A.V., Pokhilenko, N.P.Eitelite in sheared peridotite xenoliths from Udachnaya-East kimberlite pipe ( Russia) - a new locality and host rock type.European Journal of Mineralogy, Vol. 25, pp. 825-834.Russia, YakutiaDeposit - Udachnaya
DS201412-0798
2014
Golovin, A.V.Sharygin, I.S., Litasov, K.D., Shatskiy, A., Golovin, A.V., Ohtani, E., Pokhilenko, N.P.Melting phase relations of the Udachnaya-East Group 1 kimberlite at 3.0-6.5GPa: experimental evidence for alkali-carbonatite composition of primary kimberlite melts and implications for mantle plumes.Gondwana Research, in press availableRussiaDeposit - Udachnaya-East
DS201509-0401
2015
Golovin, A.V.Ionov, D.A., Carlson, R.W., Doucet, L.S., Golovin, A.V., Oleinikov, O.B.The age and history of the lithospheric mantle of the Siberian craton: Re-Os and PGE study of peridotite xenoliths from the Obnazhennaya kimberlite.Earth and Planetary Science Letters, Vol. 428, pp. 108-119.Russia, SiberiaDeposit - Obnazhennaya

Abstract: The formation age of the lithospheric mantle of the Siberian craton (one of the largest on Earth) is not well established; nearly all published whole-rock Re–Os data are for mantle xenoliths from a single kimberlite in the center of the craton (Udachnaya). We report Re–Os isotope and PGE concentration data for 19 spinel and garnet peridotite xenoliths from the Obnazhennaya kimberlite in the northeastern portion of the craton. Most samples in this study, and many Obnazhennaya peridotites in general, show a combination of relatively low Al2O3 (0.1–2%) with high CaO (1.4–4%) concentrations. Only four dunites and harzburgites in our sample suite have low contents of both Al2O3 and CaO (0.1–0.8%), but their relatively low Mg# (0.888–0.919) and highly variable Os concentrations (0.6–35 ppb) suggest they may have formed in melt migration channels rather than as residues of partial melt extraction. A group of six Ca-rich (2.0–3.2% CaO) peridotites yields the highest Re–Os model ages (mean TRD = 2.8 Ga, mean TMA = 3.5 Ga). Eight peridotites with low to moderate Al2O3 (<2%) and Mg# ?0.91, including three low-Ca harzburgites, yield lower Re–Os model ages (mean TRD = 1.9 Ga, mean TMA = 2.2 Ga). The remainder of the samples may not yield meaningful TRD ages because they are not refractory (Al2O3 >2.6% and/or Mg# ?0.90). We interpret these results as evidence for a two-stage formation of the lithospheric mantle. The peridotites formed at the two stages show very similar chemical compositions. The enrichment in Ca, which we attribute to widespread post-melting metasomatism by carbonate-rich melts, may have taken place either at the end of the Archean melting event, when at least one Ca–Al-rich peridotite was formed, or later. The combined Re–Os age data on xenoliths from Obnazhennaya and Udachnaya suggest that the lithospheric mantle beneath the Siberian craton was not formed in a single event, but grew in at least two events, one in the late Archean and the other in the Paleoproterozoic. This study further indicates that the formation of highly melt-depleted lithospheric mantle was not limited to the Archean, but continued well into the Paleoproterozoic when the Siberian craton was stabilized.
DS201604-0625
2015
Golovin, A.V.Sharygin, I.S., Litasov, K.D., Shatskiy, A., Golovin, A.V., Ohtani, E., Pokhilenko, N.P.Melting phase relations of the Udachnaya-East group 1 kimberlite at 3.0-6.5 Gpa: experimental evidence for alkali- carbonatite composition of primary kimberlite melts and implications for mantle plumes.Gondwana Research, Vol. 28, pp. 1391-1414.RussiaDeposit - Udachnaya -East

Abstract: Experiments on the origin of the Udachnaya-East kimberlite (UEK) have been performed using a Kawai-type multianvil apparatus at 3-6.5GPa and 900-1500°C. The studied composition represents exceptionally fresh Group-I kimberlite containing (wt.%): SiO2=25.9, TiO2=1.8, Al2O3=2.8, FeO=9.0, MgO=30.1, CaO=12.7, Na2O=3.4, K2O=1.3, P2O5=1.0, Cl=0.9, CO2=9.9, and H2O=0.5. The super-solidus assemblage consists of melt, olivine (Ol), Ca-rich (26.0-30.2wt.% CaO) garnet (Gt), Al-spinel (Sp), perovskite (Pv), a CaCO3 phase (calcite or aragonite), and apatite. The low pressure assemblage (3-4GPa) also includes clinopyroxene. The apparent solidus was established between 900 and 1000°C at 6.5GPa. At 6.5GPa and 900°C Na-Ca carbonate with molar ratio of (Na+K)/Ca?0.44 was observed. The UEK did not achieve complete melting even at 1500°C and 6.5GPa, due to excess xenogenic Ol in the starting material. In the studied P-T range, the melt has a Ca-carbonatite composition (Ca#=molar Ca/(Ca+Mg) ratio=0.62-0.84) with high alkali and Cl contents (7.3-11.4wt.% Na2O, 2.8-6.7wt.% K2O, 1.6-3.4wt.% Cl). The K, Na and Cl contents and Ca# decrease with temperature. It is argued that the primary kimberlite melt at depths>200km was an essentially carbonatitic (<5wt.% SiO2), but evolved toward a carbonate-silicate composition (up to 15-20wt.% SiO2) during ascent. The absence of orthopyroxene among the run products indicates that xenogenic orthopyroxene was preferentially dissolved into the kimberlite melt. The obtained subliquidus phase assemblage (Ol+Sp+Pv+Ca-rich Gt) at P-T conditions of the UEK source region, i.e. where melt was in the last equilibrium with source rock before magma ascent, differs from the Opx-bearing peridotitic mineral assemblage of the UEK source region. This difference can be ascribed to the loss of substantial amounts of CO2 from the kimberlite magma at shallow depths, as indicated by both petrological and experimental data. Our study implies that alkali-carbonatite melt would be a liquid phase within mantle plumes generated at the core-mantle boundary or shallower levels of the mantle, enhancing the ascent velocity of the plumes. We conclude that the long-term activity of a rising hot mantle plume and associated carbonatite melt (i.e. kimberlite melt) causes thermo-mechanical erosion of the subcontinental lithosphere mantle (SCLM) roots and creates hot and deformed metasomatic regions in the lower parts of the SCLM, which corresponds to depths constrained by P-T estimates of sheared Gt-peridotite xenoliths. The sheared Gt-peridotites undoubtedly represent samples of these regions.
DS201606-1095
2016
Golovin, A.V.Ilyina, O.V., Tychkov, N.S., Agashev, A.M., Golovin, A.V., Izokh, A.E., Kozmenko, O.A., Poikilanko, N.P.PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe ( Yakutia).Doklady Earth Sciences, Vol. 467, 2, pp. 408-411.Russia, YakutiaDeposit - Udachnaya

Abstract: The results of the first study of the PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe (Yakutia) are presented here. The complex character of evolution of the PGE composition in the Deformed lherzolites is assumed to be the result of silicate metasomatism. At the first stage, growth in the amount of clinopyroxene and garnet in the rock is accompanied by a decrease in the concentration of the compatible PGE (Os, Ir). During the final stage, the rock is enriched with incompatible PGE (Pt, Pd) and Re possible due to precipitation of submicron-sized particles of sulfides in the interstitial space of these mantle rocks.
DS201606-1115
2016
Golovin, A.V.Sharygin, I.S., Golovin, A.V., Korsakov, A.V., Pokhilenko, N.P.Tychite in mantle xenoliths from kimberlites: the first find of a new genetic type.Doklady Earth Sciences, Vol. 467, 1, pp. 270-274.Russia, YakutiaDeposit -Udachnaya East

Abstract: Tychite Na6Mg2(CO3)4(SO3) is a rare natural Na and Mg sulfatocarbonate. It is found only as minor mineral in deposits of saline lakes in the United States, Canada, Uganda, and China. In these continental evaporites tychite has sedimentary genesis. In this study, we report the first occurrence of tychite as a crystal phase in the melt inclusions in olivine from mantle xenoliths of the Udachnaya-East kimberlite pipe. This find provides an evidence for the probability of tychite crystallization from melts; i.e., this rare sulfatocarbonate may have a magmatic origin as well.
DS201610-1874
2016
Golovin, A.V.Jean, M.M., Taylor, L.A., Howarth, G.H., Peslier, A.H., Fedele, L., Bodnar, R.J., Guan, Y., Doucet, L.S., Ionov, D.A., Logvinova, A.M., Golovin, A.V., Sobolev, N.V.Olivine inclusions in Siberian diamonds and mantle xenoliths: contrasting water and trace -element contents.Lithos, in press available 11p.Russia, SiberiaDiamond inclusions
DS201610-1888
2016
Golovin, A.V.Mikhailenko, D.S., Korsakov, A.V., Golovin, A.V., Zelenovskiy, P.S., Pohilenko, N.P.The first finding of graphite inclusion in diamond from mantle rocks: the result of the study of eclogite xenolith from Udachnaya pipe ( Siberian craton).Doklady Earth Sciences, Vol. 469, 2, pp. 870-873.RussiaDeposit - Udachnaya

Abstract: A xenolith of eclogite from the kimberlite pipe Udachnaya-East, Yakutia Grt+Cpx+Ky + S + Coe/Qtz + Dia + Gr has been studied. Graphite inclusions in diamond have been studied in detail by Confocal Raman (CR) mapping. The graphite inclusion in diamond has a highly ordered structure and is characterized by a substantial shift in the band (about 1580 cm-1) by 7 cm-1, indicating a significant residual strain in the inclusion. According to the results of FTIR spectroscopic studies of diamond crystals, a high degree of nitrogen aggregation has been detected: it is present mainly in form A, which means an "ancient" age of the diamonds. In the xenolith studied, the diamond formation occurred about 1 Byr, long before their transport by the kimberlite melt, and the conditions of the final equilibrium were temperatures of 1020 ± 40°C at 4.7 GPa. Thus, these graphite inclusions found in a diamond are the first evidence of crystallization of metastable graphite in a diamond stability field. They were formed in rocks of the upper mantle significantly below (?20 km) the graphite-diamond equilibrium line.
DS201611-2124
2016
Golovin, A.V.Mikhailenko, D.S., Korsakov, A.V., Zelenovskiy, P.S., Golovin, A.V.Graphite diamond relations in mantle rocks: evidence from an eclogitic xenolith from the Udachnaya kimberlite, ( Siberian craton).American Mineralogist, Vol. 101, pp. 2155-2167.RussiaDeposit - Udachnaya

Abstract: Relations of graphite and diamond have been studied in a garnet-kyanite-clinopyroxene+sulfide+coesite/quartz+diamond+graphite eclogite xenolith from the Udachnaya-East kimberlite pipe in the Yakutian diamond province. Euhedral crystals of diamond and graphite occur in the intra- and intergranular space. The equilibrium conditions of diamond formation reconstructed by geothermobarometry for the Grt-Cpx-Ky-Coe mineral assemblage are 1020 ± 40 °C and 4.7 GPa. Raman imaging of graphite enclosed in diamond shows high ordering and a 9 cm?1 shift of the ~1580 cm?1 band. This Raman shift of graphite, as well as a 5 cm?1 shift of the 1332 cm?1 band of diamond, indicate large residual stress in graphite and in diamond around the inclusion, respectively. According to FTIR spectroscopy, nitrogen in diamond is highly aggregated and exists mainly as the A centers, while no other phases occur near graphite inclusions. Therefore, diamond in the analyzed eclogite sample must be quite old: it likely had crystallized long (~1 Byr) before it became entrained with kimberlite melt. New data show that graphite can stay in the upper mantle for billions of years without converting to diamond. Crystallization of various carbon polymorphs, both in laboratory and natural systems, remains poorly constrained. Graphite present in mantle and UHP rocks may be a metastable phase crystallized in the diamond stability field. This fact should be taken into consideration when deducing petrological constrains and distinguishing diamond and graphite subfacies in upper mantle.
DS201611-2139
2016
Golovin, A.V.Sharygin, I.S., Litasov, K.D., Shatskiy, A., Safonov, O.G., Golovin, A.V., Ohtani, E., Pokhilenko, N.P.Experimental constraints on orthopyroxene dissolution in alkali carbonate melts in the lithospheric mantle: implications for kimberlite melt composition and magma ascent.Chemical Geology, in press available 42p.TechnologyMagma melting

Abstract: Although kimberlite magma carries large amounts of mantle-derived xenocrysts and xenoliths (with sizes up to meters), this magma ascends from the Earth's mantle (> 150-250 km) to the surface in a matter of hours or days, which enables diamonds to survive. The recently proposed assimilation-fuelled buoyancy model for kimberlite magma ascent emphasizes the importance of fluid CO2 that is produced via the reactive dissolution of mantle-derived orthopyroxene xenocrysts into kimberlite melt, which initially has carbonatitic composition. Here, we use a series of high-pressure experiments to test this model by studying the interaction of orthopyroxene (Opx) with an alkali-dolomitic melt (simplified to 0.7Na2CO3 + 0.3K2CO3 + 2CaMg(CO3)2), which is close to the melt that is produced by the partial melting of a kimberlite source, at P = 3.1-6.5 GPa and T = 1200-1600 °C, i.e., up to pressures that correspond to depths (~ 200 km) from where the ascent of kimberlite magma would start. During the first set of experiments, we study the reaction between powdered Opx and model carbonate melt in a homogeneous mixture. During the second set of experiments, we investigate the mechanism and kinetics of the dissolution of Opx crystals in alkali-dolomitic melt. Depending on the P-T conditions, Opx dissolves in the alkali-dolomitic melt (CL) either congruently or incongruently via the following reactions: Mg2Si2O6 (Opx) + CaMg(CO3)2 (CL) = CaMgSi2O6 (clinopyroxene) + 2MgCO3 (CL) and Mg2Si2O6 (Opx) = Mg2SiO4 (olivine) + SiO2 (CL). The experiments confirm that the dissolution of Opx causes gradual SiO2 enrichment in the initial carbonate melt, as previously suggested. However, the assimilation of Opx by carbonate melt does not produce fluid CO2 in the experiments because the CO2 is totally dissolved in the evolved melt. Thus, our results clearly demonstrate the absence of exsolved CO2 fluid at 3.1-6.5 GPa in ascending kimberlite magma and disprove the assimilation-fuelled buoyancy model for kimberlite magma ascent in the lithospheric mantle. We alternatively suggest that the extreme buoyancy of kimberlite magma at depths of 100-250 km is an exclusive consequence of the unique physical properties (i.e., low density, ultra-low viscosity and, thus, high mobility) of the kimberlite melt, which are dictated by its carbonatitic composition.
DS201701-0034
2016
Golovin, A.V.Surgutanova, E.A., Agashev, A.M., Demonterova, E.I., Golovin, A.V., Pokhilenko, N.P.Sr and Nd isotope composition of deformed peridotite xenoliths from Udachnaya kimberlite pipe.Doklady Earth Sciences, Vol. 471, 1, pp. 1104-1207.RussiaDeposit - Udachnaya

Abstract: New results of Rb-Sr and Sm-Nd isotope analyses have been obtained on samples of deformed peridotite xenoliths collected from the Udachnaya kimberlite pipe (Yakutia). The data obtained imply two main stages of metasomatic alteration of the lithospheric mantle base matter in the central part of the Siberian Craton. Elevated ratios of Sr isotopes may be considered as evidence of an ancient stage of metasomatic enrichment by a carbonatite melt. The acquired Nd isotope composition together with the geochemistry of the deformed peridotite xenoliths suggests that the second stage of metasomatic alteration took place shortly before formation of the kimberlite melt. The metasomatic agent of this stage had a silicate character and arrived from an asthenosphere source, common for the normal OIB type (PREMA) and the Group-I kimberlite.
DS201707-1330
2017
Golovin, A.V.Golovin, A.V., Sharygin, I.S., Korsakov, A.V.Origin of alkaline carbonates in kimberlites of the Siberian craton: evidence from melt inclusions in mantle olivine of the Udachnaya-East pipe.Chemical Geology, Vol. 455, pp. 357-375.Russiadeposit - Udachnaya East

Abstract: Alkaline carbonates hexagonal zemkorite (Na,K)2Ca(CO3)2 and orthorhombic shortite Na2Ca2(CO3)3 were found among groundmass minerals in kimberlites from some localities worldwide, including the unserpentinised units of the Udachnaya-East kimberlite. However, the source of alkalis and the origin of the unusual minerals in these kimberlites remain highly debatable. It is generally considered that they have hydrothermal or metasomatic origin while sodium may come from a crustal source. Orthorhombic nyerereite (Na,K)2Ca(CO3)2 and shortite were identified as daughter phases in secondary melt inclusions (MI) in olivine from the deepest mantle xenoliths (i.e., sheared peridotites) and in olivine xenocrysts derived from disintegrated mantle rocks from the Udachnaya-East pipe by Raman spectroscopy and SEM-EDS. The melt, hosted as the inclusions in olivine, was entrapped at a mantle depth. On the basis of similar mineralogy of MI to groundmass of the unserpentinised kimberlites, we suggest relation of MI to the Udachnaya kimberlite melts. The MI solidus temperature is as high as 500 °?. Generally, MI nyerereite is considered as a magmatic mineral but experiments show it to be stable at relatively low temperatures (LT) T ? 360 °?. Thus, strictly speaking, it is a subsolidus mineral formed from high-temperature (HT) (T < 800 °?) hexagonal (Na,K)2Ca(CO3)2 carbonate. Shortite is also a subsolidus mineral, which may form by several subsolidus reactions in multicomponent systems, such as kimberlites, while breakdown of the HT hexagonal phase (Na,K)2Ca(CO3,SO4)2 into Na2Ca2(CO3)3 (shortite) and K3Na(SO4)2 (aphthitalite) is the basic mechanism. The solidus temperature for the Udachnaya-East kimberlite is about 300 °? indicating that LT orthorhombic nyerereite may crystallise directly from the melt as well. Thus, (Na,K)2Ca(CO3)2 and Na2Ca2(CO3)3 carbonates in the groundmass of the unserpentinised Udachnaya-East kimberlites are of magmatic/subsolidus origin. This scenario for the origin of Na-K-Ca and Na-Ca carbonates in the Udachnaya-East kimberlites may have implications for other kimberlites elsewhere.
DS201707-1364
2017
Golovin, A.V.Sharygin, I.S., Litasov, K.D., Shatskiy, A., Safonov, O.G., Golovin, A.V., Ohtani, E., Pokhilenko, N.P.Experimental constraints on orthopyroxene dissolution in alkali-carbonate melts in the lithospheric mantle: implications for kimberlite melt composition and magma ascent.Chemical Geology, Vol. 455, pp. 44-56.Mantlekimberlite, carbonatite

Abstract: Although kimberlite magma carries large amounts of mantle-derived xenocrysts and xenoliths (with sizes up to meters), this magma ascends from the Earth's mantle (> 150–250 km) to the surface in a matter of hours or days, which enables diamonds to survive. The recently proposed assimilation-fuelled buoyancy model for kimberlite magma ascent emphasizes the importance of fluid CO2 that is produced via the reactive dissolution of mantle-derived orthopyroxene xenocrysts into kimberlite melt, which initially has carbonatitic composition. Here, we use a series of high-pressure experiments to test this model by studying the interaction of orthopyroxene (Opx) with an alkali-dolomitic melt (simplified to 0.7Na2CO3 + 0.3K2CO3 + 2CaMg(CO3)2), which is close to the melt that is produced by the partial melting of a kimberlite source, at P = 3.1–6.5 GPa and T = 1200–1600 °C, i.e., up to pressures that correspond to depths (~ 200 km) from where the ascent of kimberlite magma would start. During the first set of experiments, we study the reaction between powdered Opx and model carbonate melt in a homogeneous mixture. During the second set of experiments, we investigate the mechanism and kinetics of the dissolution of Opx crystals in alkali-dolomitic melt. Depending on the P-T conditions, Opx dissolves in the alkali-dolomitic melt (CL) either congruently or incongruently via the following reactions: Mg2Si2O6 (Opx) + CaMg(CO3)2 (CL) = CaMgSi2O6 (clinopyroxene) + 2MgCO3 (CL) and Mg2Si2O6 (Opx) = Mg2SiO4 (olivine) + SiO2 (CL). The experiments confirm that the dissolution of Opx causes gradual SiO2 enrichment in the initial carbonate melt, as previously suggested. However, the assimilation of Opx by carbonate melt does not produce fluid CO2 in the experiments because the CO2 is totally dissolved in the evolved melt. Thus, our results clearly demonstrate the absence of exsolved CO2 fluid at 3.1–6.5 GPa in ascending kimberlite magma and disprove the assimilation-fuelled buoyancy model for kimberlite magma ascent in the lithospheric mantle. We alternatively suggest that the extreme buoyancy of kimberlite magma at depths of 100–250 km is an exclusive consequence of the unique physical properties (i.e., low density, ultra-low viscosity and, thus, high mobility) of the kimberlite melt, which are dictated by its carbonatitic composition.
DS201711-2521
2017
Golovin, A.V.Kang, J-T, Ionov, D.A., Liu, F., Zhang, C-L., Golovin, A.V., Qin, L-P., Zhang, Z-F., Huang, F.Calcium isotopic fractionation in mantle peridotites by melting and metasomatism and Ca isotope composition of the Bulk Silicate Earth.Earth and Planetary Science Letters, Vol. 474, pp. 128-137.Mantleperidotites

Abstract: To better constrain the Ca isotopic composition of the Bulk Silicate Earth (BSE) and explore the Ca isotope fractionation in the mantle, we determined the Ca isotopic composition of 28 peridotite xenoliths from Mongolia, southern Siberia and the Siberian craton. The samples are divided in three chemical groups: (1) fertile, unmetasomatized lherzolites (3.7-4.7 wt.% Al2O3); (2) moderately melt-depleted peridotites (1.3-3.0 wt.% Al2O3) with no or very limited metasomatism (LREE-depleted cpx); (3) strongly metasomatized peridotites (LREE-enriched cpx and bulk rock) further divided in subgroups 3a (harzburgites, 0.1-1.0% Al2O3) and 3b (fertile lherzolites, 3.9-4.3% Al2O3). In Group 1, ?44/40Ca of fertile spinel and garnet peridotites, which experienced little or no melting and metasomatism, show a limited variation from 0.90 to 0.99‰ (relative to SRM 915a) and an average of 0.94 ± 0.05‰ (2SD, ), which defines the Ca isotopic composition of the BSE. In Group 2, the ?44/40Ca is the highest for three rocks with the lowest Al2O3, i.e. the greatest melt extraction degrees (average ‰, i.e. ?0.1‰ heavier than the BSE estimate). Simple modeling of modal melting shows that partial melting of the BSE with ranging from 0.10 to 0.25 can explain the Group 2 data. By contrast, ?44/40Ca in eight out of nine metasomatized Group 3 peridotites are lower than the BSE estimate. The Group 3a harzburgites show the greatest ?44/40Ca variation range (0.25-0.96‰), with ?44/40Ca positively correlated with CaO and negatively correlated with Ce/Eu. Chemical evidence suggests that the residual, melt-depleted, low-Ca protoliths of the Group 3a harzburgites were metasomatized, likely by carbonate-rich melts/fluids. We argue that such fluids may have low (?0.25‰) ?44/40Ca either because they contain recycled crustal components or because Ca isotopes, similar to trace elements and their ratios, may be fractionated by kinetic and/or chromatographic effects of melt percolation in the mantle. The ?44/40Ca in Group 3b lherzolites (0.83-0.89‰) are lower than in the BSE as well, but the effects of metasomatism on ?44/40Ca are smaller, possibly because of the high Ca contents in their protoliths and/or smaller ?44/40Ca differences between the protoliths and metasomatic agents. The BSE estimates based on fertile peridotites in this study fall in the ?44/40Ca ranges for oceanic and continental basalts, various meteorites (achondrites; carbonaceous, ordinary and enstatite chondrites), Mars, and the Moon. These results provide benchmarks for the application of Ca isotopes to planet formation, mantle evolution, and crustal recycling.
DS201712-2693
2017
Golovin, A.V.Ionov, D.A., Doucet, L.S., Pogge von Strandmann, A.E., Golovin, A.V., Korsakov, A.V.Links between deformation, chemical enrichment and Li isotope compositions in the lithospheric mantle of the central Siberian craton.Chemical Geology, Vol. 475, pp. 105-121.Russia, Siberiacraton, geochronology

Abstract: We report the concentrations ([Li]) and isotopic compositions of Li in mineral separates and bulk rocks obtained by MC-ICPMS for 14 previously studied garnet and spinel peridotite xenoliths from the Udachnaya kimberlite in the central Siberian craton as well as major and trace element compositions for a new suite of 13 deformed garnet peridotites. The deformed Udachnaya peridotites occur at > 5 GPa; they are metasomatized residues of melt extraction, which as a group experienced greater modal and chemical enrichments than coarse peridotites. We identify two sub-groups of the deformed peridotites: (a) mainly cryptically metasomatized (similar to coarse peridotites) with relatively low modal cpx (< 6%) and garnet (< 7%), low Ca and high Mg#, sinusoidal REE patterns in garnet, and chemically unequilibrated garnet and cpx; (b) modally metasomatized with more cpx and garnet, higher Ca, Fe and Ti, and equilibrated garnet and cpx. The chemical enrichments are not proportional to deformation degrees. The deformation in the lower lithosphere is caused by a combination of localized stress, heating and fluid ingress from the pathways of ascending proto-kimberlite melts, with metasomatic media evolving due to reactions with wall rocks. Mg-rich olivine in spinel and coarse garnet Udachnaya peridotites has 1.2-1.9 ppm Li and ?7Li of 1.2-5.0‰, i.e. close to olivine in equilibrated fertile to depleted off-craton mantle peridotites from literature data, whereas olivine from the deformed peridotites has higher [Li] (2.4-7.5 ppm) and a broader range of ?7Li (1.8-11.6‰), which we attribute to pre-eruption metasomatism. [Li] in opx is higher than in coexisting olivine while ?7LiOl-Opx (?7LiOl ? ?7LiOpx) ranges from ? 6.6 to 7.8‰, indicating disequilibrium inter-mineral [Li] and Li-isotope partitioning. We relate these Li systematics to interaction of lithospheric peridotites with fluids or melts that are either precursors of kimberlite magmatism or products of their fractionation and/or reaction with host mantle. The melts rich in Na and carbonates infiltrated, heated and weakened wall-rock peridotites to facilitate their deformation as well as produce high [Li] and variable, but mainly high, ?7Li in olivine. The carbonate-rich melts preferentially reacted with the opx without achieving inter-mineral equilibrium because opx is consumed by such melts, and because of small volumes and uneven distribution of the metasomatic media, as well as short time spans between the melt infiltration and the capture of the wall-rock fragments by incoming portions of ascending kimberlite magma as xenoliths. Trapped interstitial liquid solidified as cryptic components responsible for high [Li] and the lack of ?7Li balance between olivine and opx, and bulk rocks. Unaltered ?26Mg values (0.20-0.26‰) measured in several olivine separates show no effects of the metasomatism on Mg-isotopes, apparently due to high Mg in the peridotites.
DS201801-0024
2017
Golovin, A.V.Ionov, D.A., Doucet, L.S., Pogge von Strandmann, P.A.E., Golovin, A.V., Korsakov, A.V.Links between deformation, chemical enrichments and Li-isotope compositions in the lithospheric mantle of the central Siberian craton.Chemical Geology, Vol. 475, pp. 105-121.Russiadeposit - Udachnaya

Abstract: We report the concentrations ([Li]) and isotopic compositions of Li in mineral separates and bulk rocks obtained by MC-ICPMS for 14 previously studied garnet and spinel peridotite xenoliths from the Udachnaya kimberlite in the central Siberian craton as well as major and trace element compositions for a new suite of 13 deformed garnet peridotites. The deformed Udachnaya peridotites occur at > 5 GPa; they are metasomatized residues of melt extraction, which as a group experienced greater modal and chemical enrichments than coarse peridotites. We identify two sub-groups of the deformed peridotites: (a) mainly cryptically metasomatized (similar to coarse peridotites) with relatively low modal cpx (< 6%) and garnet (< 7%), low Ca and high Mg#, sinusoidal REE patterns in garnet, and chemically unequilibrated garnet and cpx; (b) modally metasomatized with more cpx and garnet, higher Ca, Fe and Ti, and equilibrated garnet and cpx. The chemical enrichments are not proportional to deformation degrees. The deformation in the lower lithosphere is caused by a combination of localized stress, heating and fluid ingress from the pathways of ascending proto-kimberlite melts, with metasomatic media evolving due to reactions with wall rocks. Mg-rich olivine in spinel and coarse garnet Udachnaya peridotites has 1.2-1.9 ppm Li and ?7Li of 1.2-5.0‰, i.e. close to olivine in equilibrated fertile to depleted off-craton mantle peridotites from literature data, whereas olivine from the deformed peridotites has higher [Li] (2.4-7.5 ppm) and a broader range of ?7Li (1.8-11.6‰), which we attribute to pre-eruption metasomatism. [Li] in opx is higher than in coexisting olivine while ?7LiOl-Opx (?7LiOl ? ?7LiOpx) ranges from ? 6.6 to 7.8‰, indicating disequilibrium inter-mineral [Li] and Li-isotope partitioning. We relate these Li systematics to interaction of lithospheric peridotites with fluids or melts that are either precursors of kimberlite magmatism or products of their fractionation and/or reaction with host mantle. The melts rich in Na and carbonates infiltrated, heated and weakened wall-rock peridotites to facilitate their deformation as well as produce high [Li] and variable, but mainly high, ?7Li in olivine. The carbonate-rich melts preferentially reacted with the opx without achieving inter-mineral equilibrium because opx is consumed by such melts, and because of small volumes and uneven distribution of the metasomatic media, as well as short time spans between the melt infiltration and the capture of the wall-rock fragments by incoming portions of ascending kimberlite magma as xenoliths. Trapped interstitial liquid solidified as cryptic components responsible for high [Li] and the lack of ?7Li balance between olivine and opx, and bulk rocks. Unaltered ?26Mg values (0.20-0.26‰) measured in several olivine separates show no effects of the metasomatism on Mg-isotopes, apparently due to high Mg in the peridotites.
DS201801-0039
2017
Golovin, A.V.Moyen, J-F., Paquette, J.L., Ionov, D.A., Gannoun, A., Korsakov, A.V., Golovin, A.V., Moine, B.N.Paleoproterozoic rejuvenation and replacement of Archean lithosphere: evidence from zircon U-Pb dating and Hf isotopes in crustal xenoliths at Udachnaya, Siberian craton.Earth and Planetary Science Letters, Vol. 458, 1, pp. 149-159.Russiadeposit - Udachnaya

Abstract: Cratons represent the oldest preserved lithospheric domains. Their lithosphere (lithospheric mantle welded to overlying Precambrian crystalline basement) is considered to be particularly robust and long-lived due to the protecting presence of buoyant and rigid “keels” made up of residual harzburgites. Although the cratons are mostly assumed to form in the Archaean, the timing of their formation remains poorly constrained. In particular, there are very few datasets describing concurrently the age of both the crustal and mantle portions of the lithosphere. In this study, we report new U-Pb ages and Hf isotope compositions for zircons in crustal xenoliths from the Udachnaya kimberlite in the central Siberian craton; this dataset includes samples from both the upper and lower portions of the crust. The zircon ages agree well with model melt-extraction Re-Os ages on refractory peridotite xenoliths from the same pipe; taken together they allow an integrated view of lithosphere formation. Our data reveal that the present day upper crust is Archaean, whereas both the lower crust and the lithospheric mantle yield Paleoproterozoic ages. We infer that the deep lithosphere beneath the Siberian craton was not formed in a single Archaean event, but grew in at least two distinct events, one in the late Archaean and the other in the Paleoproterozoic. Importantly, a complete or large-scale delamination and rejuvenation of the Archaean lower lithosphere (lower crust and lithospheric mantle) took place in the Paleoproterozoic. This further demonstrates that craton formation can be a protracted, multi-stage process, and that the present day crust and mantle may not represent complementary reservoirs formed through the same tectono-magmatic event. Further, deep cratonic lithosphere may be less robust and long living than often assumed, with rejuvenation and replacement events throughout its history.
DS201802-0242
2018
Golovin, A.V.Ionov, D.A., Doucet, L.S., Xu, Y., Golovin, A.V., Oleinikov, O.B.Reworking of Archean mantle in the NE Siberian craton by carbonatite and silicate melt metasomatism: evidence from a carbonate bearing, dunite to web sterite xenolith suite from the Obnazhennaya kimberlite.Geochimica et Cosmochimica Acta, in press available, 46p.Russia, Siberiadeposit - Obnazhennaya

Abstract: The Obnazhennaya kimberlite in the NE Siberian craton hosts a most unusual cratonic xenolith suite, with common rocks rich in pyroxenes and garnet, and no sheared peridotites. We report petrographic and chemical data for whole rocks (WR) and minerals of 20 spinel and garnet peridotites from Obnazhennaya with Re-depletion Os isotope ages of 1.8-2.9 Ga (Ionov et al., 2015a) as well as 2 pyroxenites. The garnet-bearing rocks equilibrated at 1.6-2.8 GPa and 710-1050°C. Some xenoliths contain vermicular spinel-pyroxene aggregates with REE patterns in clinopyroxene mimicking those of garnet. The peridotites show significant scatter of Mg# (0.888-0.924), Cr2O3 (0.2-1.4 wt.%) and high NiO (0.3-0.4 wt.%). None are pristine melting residues. Low-CaO-Al2O3 (?0.9 wt.%) dunites and harzburgites are melt-channel materials. Peridotites with low to moderate Al2O3 (0.4-1.8 wt.%) usually have CaO > Al2O3, and some have pockets of calcite texturally equilibrated with olivine and garnet. Such carbonates, exceptional in mantle xenoliths and reported here for the first time for the Siberian mantle, provide direct evidence for modal makeover and Ca and LREE enrichments by ephemeral carbonate-rich melts. Peridotites rich in CaO and Al2O3 (2.7-8.0 wt.%) formed by reaction with silicate melts. We infer that the mantle lithosphere beneath Obnazhennaya, initially formed in the Mesoarchean, has been profoundly modified. Pervasive inter-granular percolation of highly mobile and reactive carbonate-rich liquids may have reduced the strength of the mantle lithosphere leading the way for reworking by silicate melts. The latest events before the kimberlite eruption were the formation of the carbonate-phlogopite pockets, fine-grained pyroxenite veins and spinel-pyroxene symplectites. The reworked lithospheric sections are preserved at Obnazhennaya, but similar processes could erode lithospheric roots in the SE Siberian craton (Tok) and the North China craton, where ancient melting residues and reworked garnet-bearing peridotites are absent.The modal, chemical and Os-isotope compositions of the Obnazhennaya xenoliths produced by reaction of refractory peridotites with melts are very particular (high Ca/Al, no Mg#-Al correlations, highly variable Cr, low 187Os/188Os, continuous modal range from olivine-rich to low-olivine peridotites, wehrlites and websterites) and distinct from those of fertile lherzolites in off-craton xenoliths and peridotite massifs. These features argue against the concept of ‘refertilization’ of cratonic and other refractory peridotites by mantle-derived melts as a major mechanism to form fertile to moderately depleted lherzolites in continental lithosphere. The Obnazhennaya xenoliths represent a natural rock series produced by ‘refertilization’, but include no rocks equivalent in modal, major and trace element to the fertile lherzolites. This study shows that ‘refertilization’ yields broad, continuous ranges of modal and chemical compositions with common wehrlites and websterites that are rare among off-craton xenoliths.
DS201804-0734
2018
Golovin, A.V.Sharygin, I.S., Shatskiy, A., Litasov, K.D., Golovin, A.V., Ohtani, E., Pokhilenko, N.P.Interaction of peridotite with Ca-rich carbonatite melt at 3.1 and 6.5 Gpa: implications for merwinite formation in upper mantle, and for metasomatic origin of sublithospheric diamonds with Ca rich suite of inclusions.Contribution to Mineralogy and Petrology, Vol. 173, 22p.Mantlecarbonatite

Abstract: We performed an experimental study, designed to reproduce the formation of an unusual merwinite?+?olivine-bearing mantle assemblage recently described as a part of a Ca-rich suite of inclusions in sublithospheric diamonds, through the interaction of peridotite with an alkali-rich Ca-carbonatite melt, derived from deeply subducted oceanic crust. In the first set of experiments, we studied the reaction between powdered Mg-silicates, olivine and orthopyroxene, and a model Ca-carbonate melt (molar Na:K:Ca?=?1:1:2), in a homogeneous mixture, at 3.1 and 6.5 GPa. In these equilibration experiments, we observed the formation of a merwinite?+?olivine-bearing assemblage at 3.1 GPa and 1200 °C and at 6.5 GPa and 1300-1400 °C. The melts coexisting with this assemblage have a low Si and high Ca content (Ca#?=?molar 100?×?Ca/(Ca?+?Mg)?>?0.57). In the second set of experiments, we investigated reaction rims produced by interaction of the same Ca-carbonate melt (molar Na:K:Ca?=?1:1:2) with Mg-silicate, olivine and orthopyroxene, single crystals at 3.1 GPa and 1300 °C and at 6.5 GPa and 1400 °C. The interaction of the Ca-carbonate melt with olivine leads to merwinite formation through the expected reaction: 2Mg2SiO4 (olivine)?+?6CaCO3 (liquid)?=?Ca3MgSi2O8 (merwinite)?+?3CaMg(CO3)2 (liquid). Thus, our experiments confirm the idea that merwinite in the upper mantle may originate via interaction of peridotite with Ca-rich carbonatite melt, and that diamonds hosting merwinite may have a metasomatic origin. It is remarkable that the interaction of the Ca-carbonate melt with orthopyroxene crystals does not produce merwinite both at 3.1 and 6.5 GPa. This indicates that olivine grain boundaries are preferable for merwinite formation in the upper mantle.
DS201805-0946
2018
Golovin, A.V.Golovin, A.V., Sharygin, I.S., Kamenetsky, V.S., Korsakov, A.V., Yaxley, G.M.Alkali-carbonate melts from the base of cratonic lithospheric mantle: links to kimberlites.Chemical Geology, Vol. 483, pp. 261-274.Russiadeposit - Udachnaya

Abstract: Identification of the primary compositions of mantle-derived melts is crucial for understanding mantle compositions and physical conditions of mantle melting. However, these melts rarely reach the Earth's surface unmodified because of contamination, crystal fractionation and degassing, processes that occur almost ubiquitously after melt generation. Here we report snapshots of the melts preserved in sheared peridotite xenoliths from the Udachnaya-East kimberlite pipe, in the central part of the Siberian craton. These xenoliths are among the deepest mantle samples and were delivered by kimberlite magma from 180-230?km depth interval, i.e. from the base of the cratonic lithosphere. The olivine grains of the sheared peridotites contain secondary inclusions of the crystallized melt with bulk molar (Na?+?K)/Ca?~?3.4. Various Na-K-Ca-, Na-Ca-, Na-Mg-, Ca-Mg- and Ca-carbonates, Na-Mg-carbonates with additional anions, alkali sulphates and halides are predominant among the daughter minerals in secondary melt inclusions, whereas silicates, oxides, sulphides and phosphates are subordinate. These inclusions can be considered as Cl-S-bearing alkali-carbonate melts. The presence of aragonite, a high-pressure polymorph of CaCO3, among the daughter minerals suggests a mantle origin for these melt inclusions. The secondary melt inclusions in olivine from the sheared peridotite xenoliths and the melt inclusions in phenocrystic olivines from the host kimberlites demonstrate similarities, in daughter minerals assemblages and trace-element compositions. Moreover, alkali-rich minerals (carbonates, halides, sulphates and sulphides) identified in the studied melt inclusions are also present in the groundmass of the host kimberlites. These data suggests a genetic link between melt enclosed in olivine from the sheared peridotites and melt parental to the Udachnaya-East kimberlites. We suggest that the melt inclusions in olivine from mantle xenoliths may represent near primary, kimberlite melts. These results are new evidence in support of the alkali?carbonate composition of kimberlite melts in their source regions, prior to the kimberlite emplacement into the crust, and are in stark contrast to the generally accepted ultramafic silicate nature of parental kimberlite liquids.
DS201811-2552
2018
Golovin, A.V.Abersteiner, A., Kamenetsky, V.S., Golovin, A.V., Kamenetsky, M., Goemann, K.Was crustal contamination involved in the formation of the serpentine-free Udachnaya-East kimberlite? New insights into parental melts, liquids, liquidus assemblage and effects of alteration.Journal of Petrology, Vol. 59, 8, pp. 1467-1492.Russiadeposit - Udachnaya-East

Abstract: The petrologically unique Udachnaya-East kimberlite (Siberia, Russia) is characterised by unserpentinised and H2O-poor volcaniclastic and coherent units that contain fresh olivine, along with abundant alkali-rich carbonates, chlorides, sulphides and sulphates in the groundmass. These mineralogical and geochemical characteristics have led to two divergent models that advocate different origins. It has been suggested that the unserpentinised units from Udachnaya-East are representative of pristine unaltered kimberlite. Conversely, the alkali-chlorine-sulphur enrichment has been attributed to interactions with crustal materials and/or post-emplacement contamination by brines. The mineralogical and geochemical features and the compositions of melt inclusions in unserpentinised and serpentinised Udachnaya-East kimberlite varieties are compared in this study. Both varieties of kimberlite have similar major, compatible and incompatible trace element concentrations and primitive mantle normalised trace element patterns, groundmass textures and silicate, oxide and sulphide mineral compositions. However, these two kimberlite varieties are distinguished by: (i) the presence of unaltered olivine, abundant Na-K-Cl-S-rich minerals (i.e. chlorides, S-bearing alkali-carbonates, sodalite) and the absence of H2O-rich phases (i.e. serpentine, iowaite (Mg4Fe3+(OH)8OCl•3(H2O)) in unserpentinised samples, and (ii) the absence of alkali- and chlorine-enriched phases in the groundmass and characteristic olivine alteration (i.e. replacement by serpentine and/or iowaite) in serpentinised samples. In addition, melt inclusions hosted in olivine, monticellite, spinel and perovskite from unserpentinised and serpentinised kimberlite contain identical daughter phase assemblages that are dominated by alkali-carbonates, chlorides and sulphates/sulphides. This enrichment in alkalis, chlorine and sulphur in melt inclusions demonstrates that these elements were an intrinsic part of the parental magma. The paucity of alkali-carbonates and chlorides in the groundmass of serpentinised Udachnaya-East kimberlite is attributed to their instability and removal during post-emplacement alteration. All evidence previously used in support of crustal and brine contamination of the Udachnaya-East kimberlite is thoroughly evaluated. We demonstrate that ‘contamination models’ are inconsistent with petrographic, geochemical and melt inclusion data. Our combined data suggest that the Udachnaya-East kimberlite crystallised from an essentially H2O-poor, Si-Na-K-Cl-S-bearing carbonate-rich melt.
DS201902-0255
2019
Golovin, A.V.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Golovin, A.V., Sharygin, I.S., Giuliani, A., Rodemann, T., Spetsius, Z.V., Kamenetsky, M.Djerfisherite in kimberlites and their xenoliths: implications for kimberlite melt evolution.Contributions to Mineralogy and Petrology, Vol. 174, 8 22p. Africa, South Africa, Russia, Canada, Northwest Territoriesdeposit - Bultfontein, Roberts Victor, Udachnaya-East, Obnazhennaya, Vtorogodnitsa, Koala, Leslie

Abstract: Djerfisherite (K6(Fe,Ni,Cu)25S26Cl) occurs as an accessory phase in the groundmass of many kimberlites, kimberlite-hosted mantle xenoliths, and as a daughter inclusion phase in diamonds and kimberlitic minerals. Djerfisherite typically occurs as replacement of pre-existing Fe-Ni-Cu sulphides (i.e. pyrrhotite, pentlandite and chalcopyrite), but can also occur as individual grains, or as poikilitic phase in the groundmass of kimberlites. In this study, we present new constraints on the origin and genesis of djerfisherite in kimberlites and their entrained xenoliths. Djerfisherite has extremely heterogeneous compositions in terms of Fe, Ni and Cu ratios. However, there appears to be no distinct compositional range of djerfisherite indicative of a particular setting (i.e. kimberlites, xenoliths or diamonds), rather this compositional diversity reflects the composition of the host kimberlite melt and/or interacting metasomatic medium. In addition, djerfisherite may contain K and Cl contents less than the ideal formula unit. Raman spectroscopy and electron backscatter diffraction (EBSD) revealed that these K-Cl poor sulphides still maintain the same djerfisherite crystal structure. Two potential mechanisms for djerfisherite formation are considered: (1) replacement of pre-existing Fe-Ni-Cu sulphides by djerfisherite, which is attributed to precursor sulphides reacting with metasomatic K-Cl bearing melts/fluids in the mantle or the transporting kimberlite melt; (2) direct crystallisation of djerfisherite from the kimberlite melt in groundmass or due to kimberlite melt infiltration into xenoliths. The occurrence of djerfisherite in kimberlites and its mantle cargo from localities worldwide provides strong evidence that the metasomatising/infiltrating kimberlite melt/fluid was enriched in K and Cl. We suggest that kimberlites originated from melts that were more enriched in alkalis and halogens relative to their whole-rock compositions.
DS201902-0279
2018
Golovin, A.V.Ionov, D.A., Doucet, L.S., Xu, Y., Golovin, A.V., Oleinikov, O.B.Reworking of Archean mantle in the NE Siberian craton by carbonatite and silicate melt metasomatism: evidence from a carbonate bearing, dunite to websterite xenolith suite from the Obnazhennaya kimberlite.Geochimica et Cosmochimica Acta, Vol. 224, pp. 132-153.Russia, Siberiadeposit - Obnazhennaya

Abstract: The Obnazhennaya kimberlite in the NE Siberian craton hosts a most unusual cratonic xenolith suite, with common rocks rich in pyroxenes and garnet, and no sheared peridotites. We report petrographic and chemical data for whole rocks (WR) and minerals of 20 spinel and garnet peridotites from Obnazhennaya with Re-depletion Os isotope ages of 1.8-2.9?Ga (Ionov et al., 2015a) as well as 2 pyroxenites. The garnet-bearing rocks equilibrated at 1.6-2.8?GPa and 710-1050?°C. Some xenoliths contain vermicular spinel-pyroxene aggregates with REE patterns in clinopyroxene mimicking those of garnet. The peridotites show significant scatter of Mg# (0.888-0.924), Cr2O3 (0.2-1.4?wt.%) and high NiO (0.3-0.4?wt.%). None are pristine melting residues. Low-CaO-Al2O3 (?0.9?wt.%) dunites and harzburgites are melt-channel materials. Peridotites with low to moderate Al2O3 (0.4-1.8?wt.%) usually have CaO?>?Al2O3, and some have pockets of calcite texturally equilibrated with olivine and garnet. Such carbonates, exceptional in mantle xenoliths and reported here for the first time for the Siberian mantle, provide direct evidence for modal makeover and Ca and LREE enrichments by ephemeral carbonate-rich melts. Peridotites rich in CaO and Al2O3 (2.7-8.0?wt.%) formed by reaction with silicate melts. We infer that the mantle lithosphere beneath Obnazhennaya, initially formed in the Mesoarchean, has been profoundly modified. Pervasive inter-granular percolation of highly mobile and reactive carbonate-rich liquids may have reduced the strength of the mantle lithosphere leading the way for reworking by silicate melts. The latest events before the kimberlite eruption were the formation of the carbonate-phlogopite pockets, fine-grained pyroxenite veins and spinel-pyroxene symplectites. The reworked lithospheric sections are preserved at Obnazhennaya, but similar processes could erode lithospheric roots in the SE Siberian craton (Tok) and the North China craton, where ancient melting residues and reworked garnet-bearing peridotites are absent. The modal, chemical and Os-isotope compositions of the Obnazhennaya xenoliths produced by reaction of refractory peridotites with melts are very particular (high Ca/Al, no Mg#-Al correlations, highly variable Cr, low 187Os/188Os, continuous modal range from olivine-rich to low-olivine peridotites, wehrlites and websterites) and distinct from those of fertile lherzolites in off-craton xenoliths and peridotite massifs. These features argue against the concept of ‘refertilization’ of cratonic and other refractory peridotites by mantle-derived melts as a major mechanism to form fertile to moderately depleted lherzolites in continental lithosphere. The Obnazhennaya xenoliths represent a natural rock series produced by ‘refertilization’, but include no rocks equivalent in modal, major and trace element to the fertile lherzolites. This study shows that ‘refertilization’ yields broad, continuous ranges of modal and chemical compositions with common wehrlites and websterites that are rare among off-craton xenoliths.
DS201902-0280
2019
Golovin, A.V.Ionov, D.A., Qi, Y-H., Kang, J-T., Golovin, A.V., Oleinikov, O.B., Zheng, W., Anbar, A.D., Zhang, Z-F., Huang, F.Calcium isotopic signatures of carbonatite and silicate metasomatism, melt percolation and crustal recycling in the lithospheric mantle.Geochimica et Cosmochimica Acta, Vol. 248, pp. 1-13.Russia, Siberiacarbonatite

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

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

Abstract: Ca isotopes can be strongly fractionated at the Earth’s surface and thus may be tracers of subducted carbonates and other Ca-rich surface materials in mantle rocks, magmas and fluids. However, the ?44/40Ca range in the mantle and the scope of intra-mantle isotope fractionation are poorly constrained. We report Ca isotope analyses for 22 mantle xenoliths: four basalt-hosted refractory peridotites from Tariat in Mongolia and 18 samples from the Obnazhennaya (Obn) kimberlite on the NE Siberian craton. Obn peridotites are Paleoproterozoic to Archean melting residues metasomatised by carbonate-rich and/or silicate melts including unique xenoliths that contain texturally equilibrated carbonates. ?44/40Ca in 15 Obn xenoliths shows limited variation (0.74-0.97‰) that overlaps the value (0.94?±?0.05‰) inferred for the bulk silicate Earth from data on fertile lherzolites, but is lower than ?44/40Ca for non-metasomatised refractory peridotites from Mongolia (1.10?±?0.03‰). Bulk ?44/40Ca in four Obn peridotites containing metasomatic carbonates ranges from 0.81?±?0.08‰ to 0.83?±?0.06‰, with similar values in acid-leachates and leaching residues, indicating isotopic equilibration of the carbonates with host rocks. We infer that (a) metasomatism tends to decrease ?44/40Ca values of the mantle, but its effects are usually limited (?0.3‰); (b) Ca isotopes cannot distinguish “carbonatite” and “silicate” types of mantle metasomatism. The lowest ?44/40Ca value (0.56‰) was obtained for a phlogopite-bearing Obn peridotite with a very high Ca/Al of 8 suggesting that the greatest metasomatism-induced Ca isotope shifts may be seen in rocks initially low in Ca that experienced significant Ca input leading to high Ca/Al. Two Obn peridotites, a dunite (melt channel material) and a veined spinel wehrlite, have high ?44/40Ca values (1.22‰ and 1.38‰), which may be due to isotope fractionation by diffusion during silicate melt intrusion and percolation in the host mantle. Overall, we find no evidence that recycling of crustal carbonates may greatly affect Ca isotope values in the global mantle or on a regional scale.
DS201905-1014
2019
Golovin, A.V.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Golovin, A.V., Gornova, M.A.Polymineralic inclusions in kimberlite hosted megacrysts: implications for kimberlite melt evolution.Lithos, doi.101016/j.lithos .2019.04.004 42p.Canada, Northwest Territories, Russiadeposit - Diavik, Jericho, Leslie, Udachnaya East

Abstract: Megacrysts are large (cm to >20?cm in size) mantle-derived crystals, which are commonly entrained by kimberlite magmas, comprising of olivine, orthopyroxene, clinopyroxene, phlogopite, garnet, ilmenite and zircon as common phases. Numerous studies have shown megacrysts to contain polymineralic inclusions, which have been interpreted to represent entrapped kimberlite melt. To constrain the origin of these inclusions in megacrysts and their relationship to kimberlite magmatism, we present a detailed petrographic and geochemical study of clinopyroxene and olivine megacrysts and their hosted inclusions from the Diavik, Jericho, Leslie (Slave Craton, Canada) and Udachnaya-East (Siberian Craton, Russia) kimberlites. The studied megacrysts are between 1 and 3?cm in size and representative of both the Cr-rich and Cr-poor suites. Megacrysts contain two types of inclusions: i. Large (<0.5-5?mm in size) round-to-irregular shaped polymineralic inclusions, which are composed of minerals similar to the host kimberlite groundmass, and consist of olivine, calcite, spinel, perovskite, phlogopite and apatite (± serpentine, alkali-carbonates, alkali-chlorides, barite). ii. Swarms/trails of ‘micro melt inclusions’ (MMI; <1-5??m in size), which surround polymineralic inclusions, veins and fractures, thereby forming a ‘spongy’ texture. MMIs generally contain multiphase assemblages similar to polymineralic inclusions as well as various additional phases, such as alkali-carbonates or alkali-chlorides, which are typically absent in polymineralic inclusions and the surrounding kimberlite groundmass. Textural and geochemical evidence suggests that polymineralic inclusions in megacrysts crystallised from kimberlite melt, which infiltrated along fracture/vein networks. The polymineralic inclusion assemblages resulted from disequilibria reactions between the host megacryst and infiltrating kimberlite melt, which was likely enhanced by rapidly changing conditions during magmatic ascent. The connectivity of polymineralic inclusions to the kimberlite groundmass via network veins/fractures suggests that they are susceptible to infiltrating post-emplacement fluids. Therefore, the vast majority of polymineralic inclusions are unlikely to represent ‘pristine’ entrapped kimberlite melt. In contrast, MMIs are isolated within megacrysts (i.e. not connected to fractures/veins and therefore shielded from post-magmatic fluids) and probably represent entrapped remnants of the variably differentiated kimberlite melt, which was more enriched in alkalis-Cl-S-CO2 than serpentinised polymineralic inclusions and the host rocks exposed at Earth's surface as kimberlites.
DS201905-1034
2019
Golovin, A.V.Golovin, A.V., Sharygin, I.S., Kamenetsky, V.S., Korsakov, A.V., Yaxley, G.M.Alkali-carbonate melts from the base of cratonic lithospheric mantle: links to kimberlites.Chemical Geology, Vol. 483, pp. 261-274.Russia, Yakutiadeposit - Udachnaya -East

Abstract: Identification of the primary compositions of mantle-derived melts is crucial for understanding mantle compositions and physical conditions of mantle melting. However, these melts rarely reach the Earth's surface unmodified because of contamination, crystal fractionation and degassing, processes that occur almost ubiquitously after melt generation. Here we report snapshots of the melts preserved in sheared peridotite xenoliths from the Udachnaya-East kimberlite pipe, in the central part of the Siberian craton. These xenoliths are among the deepest mantle samples and were delivered by kimberlite magma from 180-230?km depth interval, i.e. from the base of the cratonic lithosphere. The olivine grains of the sheared peridotites contain secondary inclusions of the crystallized melt with bulk molar (Na?+?K)/Ca?~?3.4. Various Na-K-Ca-, Na-Ca-, Na-Mg-, Ca-Mg- and Ca-carbonates, Na-Mg-carbonates with additional anions, alkali sulphates and halides are predominant among the daughter minerals in secondary melt inclusions, whereas silicates, oxides, sulphides and phosphates are subordinate. These inclusions can be considered as Cl-S-bearing alkali-carbonate melts. The presence of aragonite, a high-pressure polymorph of CaCO3, among the daughter minerals suggests a mantle origin for these melt inclusions. The secondary melt inclusions in olivine from the sheared peridotite xenoliths and the melt inclusions in phenocrystic olivines from the host kimberlites demonstrate similarities, in daughter minerals assemblages and trace-element compositions. Moreover, alkali-rich minerals (carbonates, halides, sulphates and sulphides) identified in the studied melt inclusions are also present in the groundmass of the host kimberlites. These data suggests a genetic link between melt enclosed in olivine from the sheared peridotites and melt parental to the Udachnaya-East kimberlites. We suggest that the melt inclusions in olivine from mantle xenoliths may represent near primary, kimberlite melts. These results are new evidence in support of the alkali?carbonate composition of kimberlite melts in their source regions, prior to the kimberlite emplacement into the crust, and are in stark contrast to the generally accepted ultramafic silicate nature of parental kimberlite liquids.
DS201906-1341
2019
Golovin, A.V.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.
DS201910-2259
2019
Golovin, A.V.Golovin, A.V., Sharygin, I., Korsakov, A.V., Kamenetsky, V.S., Abersteiner, A.Can primitive kimberlite melts be alkali-carbonate liquids: composition of the melt snapshots preserved in deepest mantle xenoliths.Journal of Raman Spectroscopy, in press available, 19p. PdfRussiadeposit - Udachnaya

Abstract: The study of kimberlite rocks is important as they provide critical information regarding the composition and dynamics of the continental mantle and are the principal source of diamonds. Despite many decades of research, the original compositions of kimberlite melts, which are thought to be derived from depths > 150 km, remain highly debatable due to processes that can significantly modify their composition during ascent and emplacement. Snapshots of the kimberlite?related melts were entrapped as secondary melt inclusions hosted in olivine from sheared peridotite xenoliths from the Udachnaya?East pipe (Siberian craton). These xenoliths originated from 180? to 220?km depth and are among the deepest derived samples of mantle rocks exposed at the surface. The crystallised melt inclusions contain diverse daughter mineral assemblages (>30 mineral species), which are dominated by alkali?rich carbonates, sulfates, and chlorides. The presence of aragonite as a daughter mineral suggests a high?pressure origin for these inclusions. Raman?mapping studies of unexposed inclusions show that they are dominated by carbonates (>65 vol.%), whereas silicates are subordinate (<13 vol.%). This indicates that the parental melt for the inclusions was carbonatitic. The key chemical features of this melt are very high contents of alkalis, carbon dioxide, chlorine, and sulfur and extremely low silica and water. Alkali?carbonate melts entrapped in xenolith minerals likely represent snapshots of the primitive kimberlite melt. This composition is in contrast with the generally accepted notion that kimberlites originated as ultramafic silicate water?rich melts. Experimental studies revealed that alkali?carbonate melts are a very suitable diamond?forming media. Therefore, our findings support the idea that some diamonds and kimberlite magmatism may be genetically related.
DS201910-2287
2019
Golovin, A.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.
DS202004-0531
2020
Golovin, A.V.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.
DS202007-1150
2020
Golovin, A.V.Ionov, D.A., Liu, Z., Li, J., Golovin, A.V., Korsakov, A.V., Xu, Y.The age and origin of cratonic lithospheric mantle: Archean dunites vs paleoproterozoic harzburgites from the Udachnaya kimberlite, Siberian craton.Geochimica et Cosmochimica Acta, Vol. 281, pp. 67-90. pdfRussia, Siberiadeposit - Udachnaya

Abstract: Cratonic lithospheric mantle is believed to have been formed in the Archean, but kimberlite-hosted coarse peridotites from Udachnaya in the central Siberian craton typically yield Paleoproterozoic Re-depletion Os isotope ages (TRD). By comparison, olivine megacrysts from Udachnaya, sometimes called “megacrystalline peridotites”, often yield Archean TRD ages, but the nature of these rare materials remains enigmatic. We provide whole-rock (WR) Re-Os isotope and PGE analyses for 24 olivine-rich xenoliths from Udachnaya as well as modal and petrographic data, WR and mineral major and trace element compositions. The samples were selected based on (a) high olivine abundances in hand specimens and (b) sufficient freshness and size to yield representative WR powders. They comprise medium- to coarse-grained (olivine??1?cm) dunite, olivine megacrysts and low-orthopyroxene (11-21% opx) harzburgites equilibrated at 783-1154?°C and 3.9-6.5 GPa; coarse dunites have not been previously reported from Udachnaya; two xenoliths contain ilmenite. The harzburgites and dunites have similar WR variation ranges of Ca, Al, Fe, Cr and Mg# (0.917-0.934) typical of refractory cratonic peridotites, but the dunites tend to have higher MgO, NiO and Mg/Si. Mineral abundances and those of Ca and Al are not correlated with Mg#WR; they are not due to differences in melting degrees but are linked to metasomatism. Several samples with high 187Re/188Os show a positive linear correlation with 187Os/188Os with an apparent age of 0.37?Ga, same as eruption age of host kimberlite. Robust TRD ages were obtained for 16 xenoliths with low 187Re/188Os (0.02-0.13). TRD ages for low-opx harzburgites (1.9-2.1?Ga; average 2.0?±?0.1?Ga, 1 ?) are manifestly lower than for dunites and megacrysts (2.4-3.1?Ga); the latter define two subsets with average TRD of 2.6?±?0.1?Ga and 3.0?±?0.1?Ga, and TMA of 3.0?±?0.2?Ga and 3.3?±?0.1?Ga, respectively. Differences in olivine grain size (coarse vs. megacrystalline) are not related to age. The age relations suggest that the dunites and megacrysts could not be produced by re-melting of harzburgites, e.g. in arc settings, nor be melt channel materials in harzburgites. Instead, they are relict fragments of lithospheric mantle formed in the Archean (likely in two events at or after 2.6?Ga and 3.0?Ga) that were incorporated into cratonic lithosphere during the final assembly of the Siberian craton in the Paleoproterozoic. A multi-stage formation of the Siberian lithospheric mantle is consistent with crustal basement ages from U-Pb dating of zircons from crustal xenoliths at Udachnaya and detrital zircons from the northern Siberian craton (1.8-2.0, 2.4-2.8 and 3.0-3.4?Ga). The new data from the Siberian and other cratons suggest that the formation of strongly melt-depleted cratonic lithosphere (e.g. Mg# ?0.92) did not stop at the Archean-Proterozoic boundary as is commonly thought, but continued in the Paleoproterozoic. The same may be valid for the transition from the ‘Archean’ (4-2.5?Ga) to modern tectonic regimes.
DS202008-1395
2019
Golovin, A.V.Golovin, A.V., Sharygin, I., Korsakov, A.V., Abersteiner, A.Can primitive kimberlitic melts be alkali-carbonate liquids: composition of the melt snapshots preserved in deepest mantle xenoliths.Journal of Raman Spectroscopy, doi.org/10.1002/jrs.5701 19p pdfRussiadeposit - Udachnaya-East

Abstract: The study of kimberlite rocks is important as they provide critical information regarding the composition and dynamics of the continental mantle and are the principal source of diamonds. Despite many decades of research, the original compositions of kimberlite melts, which are thought to be derived from depths > 150 km, remain highly debatable due to processes that can significantly modify their composition during ascent and emplacement. Snapshots of the kimberlite?related melts were entrapped as secondary melt inclusions hosted in olivine from sheared peridotite xenoliths from the Udachnaya?East pipe (Siberian craton). These xenoliths originated from 180? to 220?km depth and are among the deepest derived samples of mantle rocks exposed at the surface. The crystallised melt inclusions contain diverse daughter mineral assemblages (>30 mineral species), which are dominated by alkali?rich carbonates, sulfates, and chlorides. The presence of aragonite as a daughter mineral suggests a high?pressure origin for these inclusions. Raman?mapping studies of unexposed inclusions show that they are dominated by carbonates (>65 vol.%), whereas silicates are subordinate (<13 vol.%). This indicates that the parental melt for the inclusions was carbonatitic. The key chemical features of this melt are very high contents of alkalis, carbon dioxide, chlorine, and sulfur and extremely low silica and water. Alkali?carbonate melts entrapped in xenolith minerals likely represent snapshots of the primitive kimberlite melt. This composition is in contrast with the generally accepted notion that kimberlites originated as ultramafic silicate water?rich melts. Experimental studies revealed that alkali?carbonate melts are a very suitable diamond?forming media. Therefore, our findings support the idea that some diamonds and kimberlite magmatism may be genetically related.
DS202008-1437
2020
Golovin, A.V.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.
DS202009-1641
2020
Golovin, A.V.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.
DS202110-1637
2021
Golovin, A.V.Solovev, K.A., Golovin, A.V., Sharygin, I.S., Pokhilenko, N.P.Origin of epigenetic iron-rich olivine in lherzolite xenolith from the Udachnaya kimberlite pipe ( Siberian craton).Doklady Earth Sciences, Vol. 499, 2, pp. 619-622.Russiadeposit - Udachnaya

Abstract: Olivine is the most common rock-forming mineral of the majority of the lithospheric mantle rocks beneath ancient cratons. This study provides the information about an epigenetic olivine in a lherzolite xenolith from the Udachnaya kimberlite pipe (Siberian craton), which is characterized by lower Mg# compared to the rock-forming one (Mg# = 87.4). The iron-rich olivine has been observed in the epigenetic mineral assemblage that forms a kelyphite shell around the rock-forming garnet. Olivine from the kelyphite shell occurs as both homogeneous grains (Mg# = 84.3-85.9) and zoned grains (Mg# = 85.1-87.5). The major and minor elements asymmetric zoning patterns have been found in the rock-forming olivine grains at the contact with the kelyphite shell. These olivine grains have an outer low Mg# (up to 85.9) zone at the contact with the kelyphite shell as the epigenetic olivine grains in the kelyphite shell. We suggest that the iron-rich epigenetic olivine was produced as the result of a reaction between the rock-forming garnet and the primitive kimberlite melt. During this reaction, a hybrid melt was formed in the interstitial space. The hybrid melt was iron-enriched relative to the kimberlite melt. The source of iron for the micro-portions of the interstitial hybrid melt was the rock-forming garnet.
DS202111-1775
2021
Golovin, A.V.Mikhailenko, D.S., Aulbach, S., Korsakov, A.V., Golovin, A.V., Malygina, E.V., Gerdes, A., Stepanov, A.S., Xu, Y-G.Origin of graphite-diamond bearing eclogites from Udachnaya kimberlite pipe.Journal of Petrology, Vol. 62, 8, pp. 1-32. pdfRussiadeposit - Udachnaya

Abstract: Kimberlite-borne mantle eclogites represent an important diamond source rock. Although the origin and stability of diamond, as opposed to its low-pressure polymorph graphite, have been studied for decades, their relationship in rare natural samples where both polymorphs coexist remains poorly constrained. To shed new light on this issue, seven graphite-diamond-bearing eclogites from the kimberlite pipe Udachnaya, Siberian craton were comprehensively investigated with respect to their petrography, mineral chemical composition and omphacite 87Sr/86Sr, acquired in situ by laser ablation multicollector inductively coupled plasma mass spectrometry. The calculated P-T conditions for basaltic group eclogites (Eu/Eu* < 1) correspond to a pressure range of 4•8-6•5?GPa and temperatures of 1060-1130?°C, whereas gabbroic eclogites with positive Eu- and Sr-anomalies have a smaller pressure variation (4•8-5•8?GPa), but a larger range in temperature (990-1260?°C). Reconstructed bulk compositions for gabbroic eclogites indicate an oceanic crustal origin for their protoliths, with accumulation of plagioclase and olivine ± clinopyroxene (gabbronorite or olivine gabbro). The protoliths of basaltic eclogites probably formed from the complementary residual melt. The presence of coesite and low Mg# in basaltic eclogites suggest that their light rare earth element depletion was the result of <10?% partial melting during subsequent subduction and emplacement into the cratonic lithosphere. Extremely unradiogenic 87Sr/86Sr (0•70091-0•70186 for six of seven samples) not only provides new evidence for the Archean age (2•5-2•9?Gyr) of Yakutian graphite-diamond-bearing eclogites and for formation of their protoliths in a depleted mantle source, but also suggests that they were not significantly metasomatically overprinted after their formation, despite their extended residence in the cratonic mantle lithosphere. The mineralogical and petrographic features indicate that the primary mineral association includes garnet, omphacite, ± coesite, ± kyanite, ± rutile, graphite, and diamond. Graphite occurs in the samples in the form of idiomorphic crystals (the longest dimensions being 0•4-1?mm) in garnet and kyanite and extends beyond their grain boundaries. Diamonds occur as octahedral cubic transparent, slightly colored or bright yellow crystals as large as 0•1-2?mm. Furthermore, idiomorphic and highly ordered graphite occurs as inclusions in diamond in four samples. The carbon isotope composition for diamond and graphite has a narrow range (?4 to ?6•6?‰) for both groups (gabbroic and basaltic), indicating a mantle source and limiting the role of subducted isotopically light biogenic carbon or reduction of isotopically heavy carbonate in diamond crystallization. Importantly, the presence of graphite and diamond inclusions in garnet, omphacite, and kyanite in three samples indicates a co-formation close in time to eclogitization. Combined, the petrographic and geochemical evidence suggests that both polymorphic carbon modifications can form in the diamond stability field, as also suggested by experiments and some natural examples, although the exact mechanism remains unresolved. Furthermore, this study provides natural evidence that graphite can be preserved (metastably) deep within the diamond stability field, without recrystallizing into diamond, for a long time, ?2•5?Gyr.
DS202112-1945
2021
Golovin, A.V.Sharygin, I.S., Golovin, A.V., Dymshits, A.M., Kalugina, A.D., Solovev, K.A., Malkovets, V.G., Pokhilenko, N.P.Relics of deep alkali-carbonate melt in the mantle xenolith from the Komosomolskaya-Magnitnaya kimberlite pipe ( Upper Muna field, Yakutia).Doklady Earth Sciences, Vol. 500, 2, pp. 842-847.Russia, Yakutiadeposit - Komosomolskaya-Magnitnaya

Abstract: The results of study secondary crystallized melt inclusions in olivine of a sheared peridotite xenolith from the Komsomolskaya-Magnitnaya kimberlite pipe (Upper Muna field, Yakutia) are reported. Monticellite, phlogopite, tetraferriphlogopite KMg3(Fe3+)Si3O10(F,Cl,OH), apatite, aphthitalite K3Na(SO4)2, burkeite Na6CO3(SO4)2, and carbonates, namely calcite, nyerereite (Na,K)2Ca(CO3)2, shortite Na2Ca2(CO3)3, and eitelite Na2Mg(CO3)2, were detected among the daughter minerals of the melt inclusions by the method of confocal Raman spectroscopy. The abundance of alkali carbonates in the inclusions indicates the alkali-carbonate composition of the melt. Previously, identical inclusions of alkali-carbonate melt were reported in olivine of sheared peridotites from the Udachnaya pipe (Daldyn field). Melt inclusions in sheared peridotites are the relics of a crystallized kimberlite melt that penetrated into peridotites either during the transport of xenoliths to the surface or directly in the mantle shortly prior to the entrapment of xenoliths by the kimberlite magma. If the second scenario took place, the finds of alkali-carbonate melt inclusions in sheared peridotites carried from different mantle depths in the Udachnaya and Komsomolskaya-Magnitnaya kimberlite pipes indicate a large-scale metasomatic alteration of the lithospheric mantle of the Siberian Craton by alkaline-carbonate melts, which preceded the kimberlite magmatism. However, regardless of which of the two models proposed above is correct, the results reported here support the alkali-carbonate composition of primary kimberlite melts.
DS2003-1202
2003
Golovin, N.N.Sablukova, L.I., Sablukov, S.M., Verichev, E.M., Golovin, N.N.Mantle xenoliths of the Grib pipe Zimny Bereg, Russia8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractRussia, ArkangelskDeposit - Grib
DS200412-1715
2003
Golovin, N.N.Sablukova, L.I., Sablukov, S.M., Verichev, E.M., Golovin, N.N.Mantle xenoliths of the Grib pipe Zimny Bereg, Russia8 IKC Program, Session 6, POSTER abstractRussia, Kola Peninsula, ArchangelMantle petrology Deposit - Grib
DS200512-0923
2003
Golovin, N.N.Sabulukova, L.I., Sabulkov, S.M., Verichev, E.M., Golovin, N.N.Petrography and mineral chemistry of mantle xenoliths and xenocrysts from the Grib pipe, Zimny Bereg area, Russia.Plumes and problems of deep sources of alkaline magmatism, pp. 65-95.Russia, Kola Peninsula, ArchangelXenoliths - Grib
DS200812-0380
2008
Golovin, N.N.Galimov, E.M., Palazhchenko, O.V., Verichev, E.M., Garanin, V.K., Golovin, N.N.Carbon isotope composition of diamonds from the Archangelsk diamond province.Geochemistry International, Vol. 46, 10, pp. 961-970.Russia, Archangel, Kola PeninsulaDiamond chemistry
DS200812-0386
2008
Golovin, N.N.Garanin, V.K., Kopchikov, M.B., Verichev, E.M., Golovin, N.N.New dat a on the morphology of diamonds from tholeiite basalts of the Zimneberezhnyi ( winter Coast) area of the Arkangelsk Diamondiferous province.Moscow University Geology Bulletin, Vol. 63, 2, March-April pp. 114-118.Russia, Archangel, Kola PeninsulaDiamond morphology
DS200912-0372
2009
Golovin, N.N.Khachatryan, G.K., Kopchikov, M.B., Garanin, V.K., Chukichev, M.V., Golovin, N.N.New dat a of typomorphic features of diamonds from placers in North Timan.Moscow University Geology Bulletin, Vol. 64, 2, pp. 102-110.Russia, AsiaDiamond morphology, crystallography, IR spectroscopy
DS201112-0972
2011
Golovin, N.N.Skublov, S.G., Shchukina, E.V., Guseva, N.S., Malkovets, V.G., Golovin, N.N.Geochemical characteristics of zircons from xenoliths in the V. Grib kimberlite pipe, Archangelsk Diamondiferous province.Geochemistry International, Vol. 49, 4, pp. 415-421.Russia, Kola PeninsulaGeochemistry
DS201212-0642
2012
Golovin, N.N.Shchukina, E.V., Malkovets, V.G., Golovin, N.N., Pokhilenko, N.P.Peridotitic mantle section beneath V Grib kimberlite pipe ( Arkhangelsk region, Russia): mineralogical composition P-T conditions, metasomatism.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, Archangel, Kola PeninsulaDeposit - Grib
DS201212-0643
2012
Golovin, N.N.Shchulina, E.V., Golovin, N.N., Malkovets, V.G., Pokhilenko, N.P.Mineralogy and equilibrium P-T estimates for peridotite assemblages from the V Grib kimberlite pipe (Arkangelsk kimberlite province).Doklady Earth Sciences, Vol. 444, 2, pp. 776-781.Russia, Kola Peninsula, ArchangelDeposit - Grib
DS201507-0336
2015
Golovin, N.N.Shchukina, E.V., Agashev, A.M., Golovin, N.N., Pokhilenko, N.P.Equigranualr eclogites from the V. Grib kimberlite pipe: evidence for Paleoproterozoic subduction on the territory of the Arkangelsk Diamondiferous province.Doklady Earth Sciences, Vol. 462, 1, pp. 497-501.Russia, Archangel, Kola PeninsulaDeposit - Grib
DS201610-1859
2016
Golovin A.V.Doucet, L.S., Mattielli, N., Ionov, D.A., Debouage, W., Golovin A.V.Zn isotopic heterogeneity in the mantle: a melting control?Earth and Planetary Science Letters, Vol. 451, pp. 232-240.MantlePeridotite

Abstract: We present new Zn elemental and isotope data on seventeen fertile and refractory mantle peridotite xenoliths. Eleven fertile peridotites are garnet and spinel lherzolites from Vitim and Tariat (Siberia and Mongolia) and represent some of the most pristine fertile peridotites available. Six refractory peridotites are spinel harzburgites from the Udachnaya kimberlite (Siberian craton) that are nearly pristine residues of high-degree polybaric melting at high pressure (7-4 GPa). Geochemical data suggest that Zn isotopic compositions in the peridotites have not been affected by post-melting processes such as metasomatism, contamination by the host-magmas or alteration. The fertile peridotites have uniform Zn concentrations (59±2 ppm59±2 ppm) and Zn isotopic compositions with ?66Zn (relative to JMC-Lyon-03-0749l)?=?+0.30?±?0.03‰ consistent with the Bulk Silicate Earth estimates of ?66Zn?=?+0.28?±?0.05‰ (Chen et al., 2013). The refractory peridotites have Zn concentrations ranging from 30 to 48 ppm and ?66Zn from +0.10±0.01‰+0.10±0.01‰ to +0.18±0.01‰+0.18±0.01‰ with an average of +0.14±0.03‰+0.14±0.03‰. Our data suggest that the lithospheric mantle has a heterogeneous Zn isotopic composition. Modeling of Zn isotope partitioning during partial melting of fertile mantle suggests that high degrees of melt extraction (>30%) may significantly fractionate Zn isotopes (up to 0.16‰) and that during mantle melting, Zn concentrations and isotopic compositions are mainly controlled by the stability of clinopyroxene and garnet within the melting residue. Because the stability of clinopyroxene and garnet is mainly pressure dependent we suggest that both the depth and the degrees of melt extraction may control Zn isotope fractionation during mantle melting.
DS201709-2036
2017
Golovina, A.V.Moyen, J-F., Paquette, J-L., Ionov, D.A., Korsakova, A.V., Golovina, A.V., Moine, B.N.Archean lithosphere: evidence from U-Pb zircon dating in crustal xenoliths at Udachanay, Siberian craton.Goldschmidt Conference, abstract 1p.Russiadeposit, Udachnaya

Abstract: Cratons represent the oldest preserved lithospheric domains. Their lithosphere (lithospheric mantle welded to overlying Precambrian crystalline basement) is considered to be particularly robust and long living due to the protecting presence of buoyant and rigid “keels” made up of residual harzburgites. In this study, we report new U—Pb zircon ages on crustal xenoliths from the Udachnaya kimberlite in the Siberian craton; this dataset includes samples from both the upper and lower portions of the crust. The zircon ages agree well with model melt-extraction Re-Os ages on refractory peridotite xenoliths from the same pipe; taken together they allow an integrated view of lithosphere formation. Our data reveal that the present day upper crust is Archaean, whereas both the lower crust and the lithospheric mantle yield Palaeoproterozoic ages. Consequently, the deep lithosphere beneath the Siberian craton was not formed in a single time, but grew in two distinct events, one in the late Archean and the other in the Palaeoproterozoic. We propose a two-stage scenario for the formation of the Siberian craton involving delamination and rejuvenation of the Archean lower lithosphere (lower crust and lithospheric mantle) in the Palaeoproterozoic. This demonstrates that craton formation can be a protracted, multi-stage process, and that the present day crust and mantle do not represent complementary reservoirs formed through the same episode.
DS201709-2037
2017
Golovina, A.V.Moyen, J-F., Paquette, J-L., Ionov, D.A., Korsakova, A.V., Golovina, A.V., Moine, B.N.Paleoproterozoic rejuvenation of an Archean lithosphere: evidence from U-Pb zircon dating in crustal xenoliths at Udachanaya, Siberian craton.Goldschmidt Conference, abstract 1p.Russia, Siberiadeposit, Udachnaya

Abstract: Cratons represent the oldest preserved lithospheric domains. Their lithosphere (lithospheric mantle welded to overlying Precambrian crystalline basement) is considered to be particularly robust and long-lived due to the protecting presence of buoyant and rigid “keels” made up of residual harzburgites. Although the cratons are mostly assumed to form in the Archaean, the timing of their formation remains poorly constrained. In particular, there are very few datasets describing concurrently the age of both the crustal and mantle portions of the lithosphere. In this study, we report new U–Pb ages and Hf isotope compositions for zircons in crustal xenoliths from the Udachnaya kimberlite in the central Siberian craton; this dataset includes samples from both the upper and lower portions of the crust. The zircon ages agree well with model melt-extraction Re–Os ages on refractory peridotite xenoliths from the same pipe; taken together they allow an integrated view of lithosphere formation. Our data reveal that the present day upper crust is Archaean, whereas both the lower crust and the lithospheric mantle yield Paleoproterozoic ages. We infer that the deep lithosphere beneath the Siberian craton was not formed in a single Archaean event, but grew in at least two distinct events, one in the late Archaean and the other in the Paleoproterozoic. Importantly, a complete or large-scale delamination and rejuvenation of the Archaean lower lithosphere (lower crust and lithospheric mantle) took place in the Paleoproterozoic. This further demonstrates that craton formation can be a protracted, multi-stage process, and that the present day crust and mantle may not represent complementary reservoirs formed through the same tectono-magmatic event. Further, deep cratonic lithosphere may be less robust and long living than often assumed, with rejuvenation and replacement events throughout its history.
DS201112-0789
2011
Golovina, T.A.Petrov, S.V., Antonov, A.V., Golovina, T.A., Zaitsev, A.N.Mineralogy of heavy minerals concentrates from the unconsolidated deposits of Eledoi and Pello Hill volcanic cones ( Gelai volcano): first preliminary dataPeralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterAfrica, TanzaniaAlkalic
DS201112-0790
2011
Golovina, T.A.Petrov, S.V., Antonov, A.V., Golovina, T.A., Zaitsev, A.N.Mineralogy of heavy minerals concentrates from the unconsolidated deposits of Eeldoi and Pello Hill volcanic cones (Gelai volcano, northern Tanzania) prel.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.111-112.Africa, TanzaniaDiamond, pyrope
DS201112-0791
2011
Golovina, T.A.Petrov, S.V., Antonov, A.V., Golovina, T.A., Zaitsev, A.N.Mineralogy of heavy minerals concentrates from the unconsolidated deposits of Eeldoi and Pello Hill volcanic cones (Gelai volcano, northern Tanzania) prel.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.111-112.Africa, TanzaniaDiamond, pyrope
DS1988-0259
1988
Golovko, A.V.Golovko, A.V., Semeneev, R.R., Visnevskii, Ya.S.Characteristics and composition of camptonite dikes from the upper reaches of the Tamshush River in the Gissar Ridge (Uzbek SSSR).(Russian)Uzbekiston Geologiya Zhurnal., (Russian), No. 5, pp. 10-12RussiaCamptonite
DS200912-0175
2009
Golovko, A.V.Divaev, F.K., Golovko, A.V., Golovko, D.P.Mineralogical pecularities of carbonatites of the Chagatay Complex ( Western Uzbekistan).alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussia, UzbekistanCarbonatite
DS201012-0242
2010
Golovko, A.V.Golovko, A.V., Kaminsky, F.V.The shoshonite absarokite picrite Karashoho pipe, Uzbekistan: an unusual diamond deposit in an atypical tectonic environment.Economic Geology, Vol. 105, pp. 825-840.Russia, UzbekistanDeposit - Karashoho
DS200912-0175
2009
Golovko, D.P.Divaev, F.K., Golovko, A.V., Golovko, D.P.Mineralogical pecularities of carbonatites of the Chagatay Complex ( Western Uzbekistan).alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussia, UzbekistanCarbonatite
DS1975-0034
1975
Golovko, M.M.Bobriyevich, A.P., Golovko, M.M., et al.Diamond Find in Upper Carboniferous Clastic Rocks of the Northwestern Donbas.Doklady Academy of Science USSR, Earth Science Section., Vol. 222, No. 1-6, PP. 118-120.RussiaKimberlite
DS200712-0367
2006
Golovkov, V.P.Golovkov, V.P., Yakovleva, S.V.Electric conductivity of the lower mantle. Methods and results.Geomagnetism and Aeronomy, American Geophysical Union, Vol. 46, 5, pp. 676-681.MantleGeophysics
DS1975-1035
1979
Golovnya, S.V.Golovnya, S.V., Naumova, I.S., Khvostova, V.P.Moissanite in Eclogites from Shubino, Southern UralsIzved. Akad. Nauk Sssr Geol. Ser., No. 1, PP. 118-120.RussiaMineralogy
DS200812-1116
2008
Golser, R.Steier, P., Liechtenstein, V.K., Djokic, D., Golser, R., Wallner, A., Alexeev, A.G., Khrunov, V.S., KutscheraCharacterization and improvement of thin natural diamond detectors for spectrometry of heavy ions below 1 MeV/amu.Nuclear Instruments and Methods in Physics Research Section A., Vol. 590, 1-3, pp. 221-226.TechnologySpectrometry
DS1985-0375
1985
Golubev, A.S.Kurdyumov, A.V., Ostrovskaya, N.F., Golubev, A.S.Mechanism of formation of lonsdaleite and its stability and real structure( a review)Soviet Journal of Superhard Material, Vol. 6, No. 4, pp. 21-31GlobalDiamond Morphology
DS1991-0319
1991
Golubev, V.Crane, K., Hecker, B., Golubev, V.Heat flow and hydrothermal vents in Lake Baikal, U.S.S.REos Transactions, Vol. 72, No. 52, December 24, pp. 585, 588RussiaTectonics, Rifting
DS1995-1950
1995
Golubev, Y.K.Vaganov, V.I., Golubev, Y.K., et al.Mineralogical indicators of presence of alkali ultrapotassic potentially diamondiferous Mesozoic...Doklady Academy of Sciences Nauk. (Russian), Vol. 341, No. 3, March pp. 373-376.RussiaEast European Platform, Ultrapotassics
DS201312-0453
2013
Golubev, Y.K.Kaminsky, F.V., Golubev, Y.K.Geological overview of Russia and its diamond deposit regions.PDAC 2013, March 4, 1/2p. AbstractRussiaOverview - geology
DS1995-0650
1995
Golubev, Yu.Golubev, Yu.Exploration in glaciated terrain: a Russian perspectiveJournal of Geochemical Exploration, Vol. 52, pp. 265-276.RussiaDiamond exploration, Geomorphology, glacial
DS201312-0666
2013
Golubev, Yu.G.Ordin, A.A., Nikolsky, A.M., Golubev, Yu.G.Lag modeling and design capacity optimization at operating diamond placer mines "Solur and Vostochny" Republic of Sakha ( Yakutia).Journal of Mining Science, Vol. 48, 3, pp. 515-524.Russia, YakutiaDeposit - Solur, Vostochny
DS1994-0635
1994
Golubev, Yu.K.Golubev, Yu.K.Heavy mineral prospecting of diamonds in areas of continental glaciation10th. Prospecting In Areas Of Glaciated Terrain, pp. 79-83. AbstractRussiaGeochemistry -heavy minerals, Geomorphology
DS201802-0274
2017
Golubev, Yu.K.Ustinov, V.N., Golubev, Yu.K., Zagainy, A.K., Kukui, I.M., Mikoev, I.L., Lobkova, L.P., Antonov, S.A., Konkin, V.D.Analysis of the African province diamond prospects in relation to the Russia mineral base development abroad. *** IN RUSOtechestvennaya Geologiya ***IN RUS, No. 6, pp. 52-66. pdfAfricadiamond - arenas
DS201802-0275
2017
Golubev, Yu.K.Ustinov, V.N., Golubev, Yu.K., Zagainy, A.K., Stegnitsky, Yu.B.The diamond bearing territories of Africa and their importance for expansion of the raw material base of the Russian diamond mining industry. ***IN RUSMineral Resources of Russia: economics and Management *** IN RUS, No. 6, pp. 66-72. pdfAfricadiamond - arenas
DS200512-0100
2004
GolubevaBogatikov, O.A., Kononova, V.A., Golubeva, Zinchuk, Ilupin, Rotman, Levsky, Ovchinnikova, KondrashovVariations in chemical and isotopic compositions of the Yakutian kimberlites and their causes.Geochemistry International, Vol. 42, 9, pp. 799-821.Russia, Siberia, YakutiaGeochemistry
DS201605-0883
2015
Golubeva, I.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
DS2003-0481
2003
Golubeva, Y.Y.Golubeva, Y.Y., Ilupin, I.P., Zhuravlev, D.Z.Rare earth elements in kimberlites of Yakutia: evidence from ICP MS dataDoklady Earth Sciences, Vol. 391, 5, pp. 693-6.Russia, YakutiaSpectroscopy
DS200412-0687
2003
Golubeva, Y.Y.Golubeva, Y.Y., Ilupin, I.P., Zhuravlev, D.Z.Rare earth elements in kimberlites of Yakutia: evidence from ICP MS data.Doklady Earth Sciences, Vol. 391, 5, pp. 693-6.Russia, YakutiaSpectroscopy
DS200412-0688
2004
Golubeva, Y.Y.Golubeva, Y.Y., Tsepin, A.I.Petrochemical and mineralogical constraints for diagnostics of Yakutian kimberlites.Doklady Earth Sciences, Vol. 397, 6, July-August pp. 798-802.Russia, YakutiaGeochemistry
DS200512-0351
2004
Golubeva, Y.Y.Golubeva, Y.Y., Tsepin, A.Petrochemical and mineralogical constraints for diagnostics of Yakutian kimberlites.Doklady Earth Sciences, Vol. 397, 6, pp. 798-803.Russia, YakutiaGeochemistry
DS200512-0560
2005
Golubeva, Y.Y.Kononova, V.A., Golubeva, Y.Y., Bogatikov, O.A., Nosova, Levsky, OvchinnikovaGeochemical diversity of Yakutian kimberlites: origin and diamond potential (ICP-MS dat a and Sr, Nd and Pb isotropy).Petrology, Vol. 13, 3, pp. 205-228.RussiaMineral chemistry
DS200812-0585
2007
Golubeva, Y.Y.Kononova, V.A., Golubeva, Y.Y., Bogatikov, O.A., Kargin, A.V.Diamond resource potential of kimberlites from the Zimny Bereg field, Arkangelsk oblast.Geology of Ore Deposits, Vol. 49, 6, pp. 421-441.Russia, Kola PeninsulaDeposit - Zimny Bereg
DS200412-0689
2004
Golubeva, Yu.Yu.Golubeva, Yu.Yu., Ovchinnikova, G.V., Levskii, L.K.Pb Sr Nd isotopic characteristics of mantle sources of kimberlites from the Nakyn field, Yakutia.Doklady Earth Sciences, Vol. 394, 2, Feb-Mar. pp. 230-234.Russia, YakutiaGeochronology
DS200712-0368
2006
Golubeva, Yu.Yu.Golubeva, Yu.Yu., Pervov, V.A., Kononova, V.A.Petrogenesis of autoliths from kimberlitic breccias in the V. Grib pipe, Arkangelsk district.Doklady Earth Sciences, Vol. 411, no. 8, pp. 1257-1262.Russia, Kola Peninsula, ArchangelDeposit - Grib
DS201112-0502
2011
Golubeva, Yu.Yu.Kargin, A.V., Golubeva, Yu.Yu., Kononova, V.A.Kimberlites of the Daldyn-Alakit region (Yakutia): spatial distribution of the rocks with different chemical characteristics.Petrology, Vol. 19, 5, pp. 496-520.Russia, YakutiaGroup 1 kimberlites
DS201112-0503
2011
Golubeva, Yu.Yu.Kargin, A.V., Golubeva, Yu.Yu., Kononova, V.A.Kimberlites of the Daldyn Alakit region ( Yakutia): spatial distribution of the rocks with different chemical characteristics.Petrology, Vol. 19, 5, pp. 496-520.RussiaPetrochemical data
DS201212-0348
2011
Golubeva, Yu.Yu.Kargin, A.V., Golubeva, Yu.Yu., Kononova, V.A.Kimberlites of the Daldyn Alakit region, Yakutia: spatial distribution of the rocks with different chemical characteristics.Petrology, Vol. 19, 5, pp. 496-520.RussiaDeposit - Daldyn-Alakit
DS201801-0027
2017
Golubeva, Yu.Yu.Kargin, A.V., Golubeva, Yu.Yu.Geochemical typification of kimberlite and related rocks of the North Anabar region, Yakutia.Doklady Earth Sciences, Vol. 477, 1, pp. 1291-1294.Russiakimberlite, alnoite, carbonatite

Abstract: The results of geochemical typification of kimberlites and related rocks (alneites and carbonatites) of the North Anabar region are presented with consideration of the geochemical specification of their source and estimation of their potential for diamonds. The content of representative trace elements indicates the predominant contribution of an asthenospheric component (kimberlites and carbonatites) in their source, with a subordinate contribution of vein metasomatic formations containing Cr-diopside and ilmenite. A significant contribution of water-bearing potassium metasomatic parageneses is not recognized. According to the complex of geochemical data, the studied rocks are not industrially diamondiferous.
DS201802-0244
2017
Golubeva, Yu.Yu.Kargin, A.V., Golubeva, Yu.Yu., Demonterova, E.I., Kovalchuk, E.V.Petrographical geochemical types of Triassic alkaline ultramafic rocks in the Northern Anabar Province, Yakutia, Russia.Petrology, Vol. 25, 6, pp. 535-565.Russia, Yakutiaorangeite

Abstract: A classification suggested for alkaline ultramafic rocks of the Ary-Mastakh and Staraya Rechka fields, Northern Anabar Shield, is based on the modal mineralogical composition of the rocks and the chemical compositions of their rock-forming and accessory minerals. Within the framework of this classification, the rocks are indentified as orangeite and alkaline ultramafic lamprophyres: aillikite and damtjernite. To estimate how much contamination with the host rocks has modified their composition when the diatremes were formed, the pyroclastic rocks were studied that abound in xenogenic material (which is rich in SiO2, Al2O3, K2O, Rb, Pb, and occasionally also Ba) at relatively low (La/Yb)PM, (La/Sm)PM, and not as much also (Sm/Zr)PM and (La/Nb)PM ratios. The isotopic composition of the rocks suggests that the very first melt portions were of asthenospheric nature. The distribution of trace elements and REE indicates that one of the leading factors that controlled the diversity of the mineralogical composition of the rocks and the broad variations in their isotopic-geochemical and geochemical characteristics was asthenosphere-lithosphere interaction when the melts of the alkaline ultramafic rocks were derived. The melting processes involved metasomatic vein-hosted assemblages of carbonate and potassic hydrous composition (of the MARID type). The alkaline ultramafic rocks whose geochemistry reflects the contributions of enriched vein assemblages to the lithospheric source material, occur in the northern Anabar Shield closer to the boundary between the Khapchan and Daldyn terranes. The evolution of the aillikite melts during their ascent through the lithospheric mantle could give rise to damtjernite generation and was associated with the separation of a C-H-O fluid phase. Our data allowed us to distinguish the evolutionary episodes of the magma-generating zone during the origin of the Triassic alkaline ultramafic rocks in the northern Anabar Shield.
DS202008-1407
2020
Golubeva, Yu.Yu.Kargin, A.V., Nosova, A.A., Sazonova, L.V., Peresetskaya, E.V., Golubeva, Yu.Yu., Lebedeva, N.M., Tretyachenko, V.V., Khvostikov, V.A., Burmii, J.P.Ilmenite from the Arkangelsk diamond province, Russia: composition, origin and indicator of diamondiferous kimberlites.Petrology, Vol. 28, 4, pp. 341-369. pdfRussia, Archangelilmenite

Abstract: To provide new insights into the origin and evolution of kimberlitic magmas with different diamond concentrations from the Arkhangelsk diamond province in northwestern Russia, we examined the major-and trace-element compositions of ilmenite from diamondiferous kimberlite of the Grib pipe and diamond barren kimberlites from the Kepino cluster (Stepnaya and TsNIGRI-Arkhangelskaya pipes). Ilmenite from diamond-barren kimberlites shows lower Mg, Ti, Cr, Ni and Cu concentrations with increase in both Fe 3+ and Fe 2+ and Nb, Ta, Zr, Hf, Zn and V concentrations. The main differences between kimberlites with different diamond contents are the Nb and Zr concentrations and their correlation patterns with Mg and Cr concentrations. Ilmenite from the Grib kimberlite has Zr concentrations <110 ppm, whereas ilmenite from the Kepino kimberlites has Zr concentrations >300 ppm. Ilmenite crystallisation within the Grib kimberlite occurred under increasing oxygen fugacity (fO 2), which may reflect assimilation of mantle peridotite by the kimberlitic magmas. Ilmenite from the Kepino kimberlites suggests its crystallisation under constant fO 2 , with the ilmenite composition being controlled by processes of fractional crystallisation of megacrystic minerals. These assumptions were confirmed with assimilation-fractional crystallisation calculations. On the basis of obtained data, we developed a model for the evolution of the kimberlitic magmas for both diamon-diferous and barren kimberlites. The diamond-bearing kimberlitic magmas were generated under intense interaction of kimberlitic magmas with the surrounding lithospheric mantle. It may be that during early modification of the lithospheric mantle by kimberlitic magmas as well as with kimberlitic magmas' local stretching and swift ascent, the capture of the mantle xenoliths was favoured over the crystallisation of phenocrysts. The formation of barren kimberlitic magmas may have occurred when the lithospheric mantle in the vicinity of ascending magmas was already geochemically equilibrated with them. It also is possible that the magma's ascent slowed under conditions of dominantly compressive stresses with crystallisation of olivine and other megacrystic phases.
DS202010-1849
2020
Golubeva, Yu.Yu.Kargin, A.V., Nosova, A.A., Sazonova, L.V., Peresetskaya, E.V., Golubeva, Yu.Yu., Lebedeva, N.M., Tretyachenko, V.V., Khvostikov, V.A., Burmii, J.P.Ilmenite from the Arkangelsk diamond province, Russia: composition, origin and indicator of diamondiferous kimberlites.Petrology, Vol. 28, 4, pp. 315-337. pdfRussia, Archangeldeposit - Grib, Kepino cluster

Abstract: To provide new insights into the origin and evolution of kimberlitic magmas with different diamond concentrations from the Arkhangelsk diamond province in north-western Russia, we examined the major- and trace-element compositions of ilmenite from diamondiferous kimberlite of the Grib pipe and diamond-barren kimberlites from the Kepino cluster (Stepnaya and TsNIGRI-Arkhangelskaya pipes). Ilmenite from diamond-barren kimberlites shows lower Mg, Ti, Cr, Ni and Cu concentrations with increase in both Fe3+ and Fe2+ and Nb, Ta, Zr, Hf, Zn and V concentrations. The main differences between kimberlites with different diamond contents are the Nb and Zr concentrations and their correlation patterns with Mg and Cr concentrations. Ilmenite from the Grib kimberlite has Zr concentrations <110 ppm, whereas ilmenite from the Kepino kimberlites has Zr concentrations >300 ppm. Ilmenite crystallisation within the Grib kimberlite occurred under increasing oxygen fugacity (fO2), which may reflect assimilation of mantle peridotite by the kimberlitic magmas. Ilmenite from the Kepino kimberlites suggests its crystallisation under constant fO2, with the ilmenite composition being controlled by processes of fractional crystallisation of megacrystic minerals. These assumptions were confirmed with assimilation-fractional crystallisation calculations. On the basis of obtained data, we developed a model for the evolution of the kimberlitic magmas for both diamondiferous and barren kimberlites. The diamond-bearing kimberlitic magmas were generated under intense interaction of kimberlitic magmas with the surrounding lithospheric mantle. It may be that during early modification of the lithospheric mantle by kimberlitic magmas as well as with kimberlitic magmas’ local stretching and swift ascent, the capture of the mantle xenoliths was favoured over the crystallisation of phenocrysts. The formation of barren kimberlitic magmas may have occurred when the lithospheric mantle in the vicinity of ascending magmas was already geochemically equilibrated with them. It also is possible that the magma’s ascent slowed under conditions of dominantly compressive stresses with crystallisation of olivine and other megacrystic phases.
DS1992-1341
1992
Golubic, S.Schlidowski, M., Golubic, S., Kimberley, M.M., McKirdy, D.M.Early organic evolutionSpringer-Verlag, 640p. approx. $ 300.00 United StatesGlobalBook -ad, Organic evolution
DS200712-0500
2007
Golubina, E.Kachevskii, S., Golubina, E., Lokteva, E., Lunin, V.Palladium on ultradisperse diamond and activated carbon: the relation between structure and activity in hydrodechlorination.Russia Journal of Physical Chemistry A., Vol. 81, 6, pp. 866-873.TechnologyMineralogy
DS200712-0501
2007
Golubina, E.Kachevskii, S., Golubina, E., Lokteva, E., Lunin, V.Palladium on ultradisperse diamond and activated carbon: the relation between structure and activity in hydrodechlorination.Russia Journal of Physical Chemistry A., Vol. 81, 6, pp. 866-873.TechnologyMineralogy
DS201212-0253
2012
Golubkova, A.Golubkova, A., Schmidt, M.V.The role of sediment derived carbonatitic melts in the origin of carbonated K-rich mantle domains.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractMantleCarbonatite
DS201501-0030
2014
Golubkova, A.Schmidt, M.W., Gao, C., Golubkova, A., Rohrbach, A., Connolly, J.A.D.Natural moissanite ( SiC) - a low temperature mineral formed from highly fractionated ultra-reducing COH-fluids.Progress in Earth and Planetary Science, Vol. 1, pp. 27-Moissanite
DS201606-1089
2016
Golubkova, A.Golubkova, A., Schmidt, M.W., Connolly, J.A.D.Ultra reducing conditions in average mantle peridotites and in podiform chromitites: a thermodynamic model for moissanite (SiC) formation.Contributions to Mineralogy and Petrology, in press available, 17p.MantlePeridotite

Abstract: Natural moissanite (SiC) is reported from mantle-derived samples ranging from lithospheric mantle keel diamonds to serpentinites to podiform chromitites in ophiolites related to suprasubduction zone settings (Luobusa, Dongqiao, Semail, and Ray-Iz). To simulate ultra-reducing conditions and the formation of moissanite, we compiled thermodynamic data for alloys (Fe-Si-C and Fe-Cr), carbides (Fe3C, Fe7C3, SiC), and Fe-silicides; these data were augmented by commonly used thermodynamic data for silicates and oxides. Computed phase diagram sections then constrain the P-T-fO2 conditions of SiC stability in the upper mantle. Our results demonstrate that: Moissanite only occurs at oxygen fugacities 6.5-7.5 log units below the iron-wustite buffer; moissanite and chromite cannot stably coexist; increasing pressure does not lead to the stability of this mineral pair; and silicates that coexist with moissanite have X Mg > 0.99. At upper mantle conditions, chromite reduces to Fe-Cr alloy at fO2 values 3.7-5.3 log units above the moissanite-olivine-(ortho)pyroxene-carbon (graphite or diamond) buffer (MOOC). The occurrence of SiC in chromitites and the absence of domains with almost Fe-free silicates suggest that ultra-reducing conditions allowing for SiC are confined to grain scale microenvironments. In contrast to previous ultra-high-pressure and/or temperature hypotheses for SiC origin, we postulate a low to moderate temperature mechanism, which operates via ultra-reducing fluids. In this model, graphite-/diamond-saturated moderately reducing fluids evolve in chemical isolation from the bulk rock to ultra-reducing methane-dominated fluids by sequestering H2O into hydrous phases (serpentine, brucite, phase A). Carbon isotope compositions of moissanite are consistent with an origin of such fluids from sediments originally rich in organic compounds. Findings of SiC within rocks mostly comprised by hydrous phases (serpentine + brucite) support this model. Both the hydrous phases and the limited diffusive equilibration of SiC with most minerals in the rocks indicate temperatures below 700-800 °C. Moissanite from mantle environments is hence a mineral that does not inform on pressure but on a low to moderate temperature environment involving ultra-reduced fluids. Any mineral in equilibrium with SiC could only contain traces of Fe2+ or Cr3+.
DS1960-0149
1961
Goman, G.O.Goman, G.O., et al.Luminescence of Diamonds from the Mir PipeGeologii i Geofiziki, No. 12, PP. 116-118.RussiaKimberlite
DS201312-0451
2013
Gomann, K.Kamenetsky, V.S., Grutter, H., Kamenetsky, M.B., Gomann, K.Parental carbonatitic melt of the kaola kimberlite ( Canada): constraints from melt inclusions in olivine and Cr-spinel, and groundmass carbonateChemical Geology, Vol. 353, pp. 96-111.Canada, Northwest TerritoriesDeposit - Kaola
DS1993-0556
1993
Gomberg, J.S.Gomberg, J.S., Ellis, M.3D-DEF a user's manual boundary element modeling ProgramUnited States Geological Survey (USGS) Open File, No. 93-0547, 15p. $ 2.50GlobalComputer Program, Program -3D-DEF.
DS1999-0008
1999
GomesAlberti, A., Castorina, Censi, Comin-Chiaramonti, GomesGeochemical characteristics of Cretaceous carbonatites from AngolaJournal of African Earth Sciences, Vol. 29, No. 4, Dec. pp. 735-59.AngolaCarbonatite, geochemistry, Parana-Angola, Etendeka Province
DS200712-0114
2007
GomesBrotzu, P., Melluso, L., Bennio, L., Gomes, Lustrino, Morbidelli, Morra, Ruberti, Tassarini, D'AntonioPetrogenesis of the Early Cenozoic potassic alkaline complex of Morro de Sao Joao, southeastern Brazil.Journal of South American Earth Sciences, Vol. 24, 1, June pp. 93-115.South America, BrazilAlkalic
DS200612-0268
2006
Gomes, C.Comin-Chiaramonti, P., Gomes, C.Mesozoic to Cenozoic alkaline magmatism in the Brazilian Platform.Thesis, University of Sao Paulo, Brazil, 750p. approx. R 63.00South America, Brazil, Paraguay, UruguayBook - alkaline rocks
DS202011-2061
2020
Gomes, C.Speciale, S., Censi, P., Gomes, C., Marques, L.Carbonatites from the southern Brazilian platform: a review. II: isotopic evidences.Open Geosciences ( researchgate), 26p. PdfSouth America, Brazilcarbonatite

Abstract: Early and Late Cretaceous alkaline and alkaline-carbonatitic complexes from southern Brazil are located along the main tectonic lineaments of the South America Platform. Calcium-, magnesium-, and ferrocarbonatites are well represented and frequently associated even in the same complex. Primary carbonates present significant variations in C-O isotopic compositions, which are mainly due to isotope exchange with H2O-CO2-rich hydrothermal fluids, whereas fractional crystallization or liquid immiscibility probably affects the ?18O and ?13C values by no more than 2?‰ Our isotope exchange model implies that the most significant isotopic variations took place in a hydrothermal environment, e.g., in the range 400-80°C, involving fluids with the CO2/H2O ratio ranging from 0.8 to 1. Sr-Nd-Pb isotope systematics highlight heterogeneous mixtures between HIMU and EMI mantle components, similar to the associated alkaline rocks and the flood tholeiites from southern Brazil. In spite of the strong variation shown by C-O isotopes, Sr-Nd-Pb-Os isotopic systematics could be related to an isotopically enriched source where the chemical heterogeneities reflect a depleted mantle "metasomatized" by small-volume melts and fluids rich in incompatible elements. These fluids are expected to have promoted crystallization of K-rich phases in the mantle, which produced a veined network variously enriched in LILE and LREE. The newly formed veins (enriched component) and peridotite matrix (depleted component) underwent a different isotopic evolution with time as reflected by the carbonatites. These conclusions may be extended to the whole Paraná-Etendeka system, where isotopically distinct parent magmas were generated following two main enrichment events of the subcontinental lithospheric mantle at 2.0-1.4 and 1.0-0.5?Ga, respectively, as also supported by Re-Os systematics. The mantle sources preserved the isotopic heterogeneities over a long time, suggesting a nonconvective lithospheric mantle beneath different cratons or intercratonic regions. Overall, the data indicate that the alkaline-carbonatitic magmatism originated from a locally heterogeneous subcontinental mantle.
DS2000-0346
2000
Gomes, C.BGomes, C.B, Bennio, Melluso, Morbidelli, Morra, RubertiPetrology and geochemistry of Cretaceous alkaline dike swarm from Cabo Frio southeastern Brasil.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, southeastDike swarm - alkaline rocks
DS1987-0627
1987
Gomes, C.B.Ruberti, E., Gomes, C.B., Dutra, C.V.Geochemical aspects of alkaline mafics of Banhadao PR. Brasil. (in Portugese)National Technical Information Service DE 88704779, DE 88704779, 27p. $ 13.95BrazilAlkaline rocks
DS1990-0582
1990
Gomes, C.B.Gomes, C.B., Ruberti, E., Morbidelli, L.Carbonatite complexes from Brasil: a reviewJournal of South American Earth Sciences, Vol. 3, No. 1, pp. 51-63BrazilCarbonatite, Review
DS1995-1299
1995
Gomes, C.B.Morbidelli, L., Gomes, C.B., et al.Mineralogical, petrological and geochemical aspects of alkaline and alkaline carbonatite associations Brasil.Earth Science Reviews, Vol. 39, No. 3-4, Dec. pp. 135-168.BrazilCarbonatite, Alkaline rocks
DS1996-0284
1996
Gomes, C.B.Comin-Chiaramonti, A., Gomes, C.B.Alkaline magmatism in central and eastern Paraguay. Relationships with coeval magmatism in BrasilCidade Univ, 400p. approx. 65.00 United StatesParaguay, BrazilAlkaline magmatism, Book - table of contents
DS1997-0133
1997
Gomes, C.B.Brotzu, P., Gomes, C.B., Melluso, L., et al.Petrogenesis of coexisting SiO2 undersaturated to SiO2 Over saturated felsic igneous rocks: alkaline complex..Lithos, Vol. 40, No. 2-4, July, pp. 133-156.BrazilAlkaline rocks, Itataia area
DS2000-0629
2000
Gomes, C.B.Matos, J.B., Gomes, C.B., Ruberti, Velazquez, V.F.Petrography and geochemistry of alkaline plugs from Sao Pedro, POr to Conceicao Morro Distante.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Mato GrossoAlkaline rocks, Paraguay Province
DS2000-0685
2000
Gomes, C.B.Morbidelli, L., Gomes, C.B., Brotzu, P., et al.The Pariquera Acu K-alkaline complex and southern Brasil lithospheric mantle source characteristics.Journal of Asian Earth Science, Vol. 18, No.2, Apr. pp. 129-50.BrazilAlkaline rocks, Lithosphere
DS2002-1374
2002
Gomes, C.B.Ruberti, E., Castorina, F., Censi, P., Comin Chiaramonti, P., Gomes, C.B.The geochemistry of the Barra do Itapirapua carbonatite ( Ponta Grossa Arch): a multiple stockwork.Journal of South American Earth Sciences, Vol. 15, No. 2, pp. 215-28.BrazilCarbonatite
DS2003-0021
2003
Gomes, C.B.Antonini, P., Comin Chiaramonti, P., Gomes, C.B., Censi, P., Riffell, B.F.The Early Proterozoic carbonatite complex of Angico dos Dias, Bahia State, Brazil:Mineralogical Magazine, Vol. 67, 5, pp. 1039-58.Brazil, BahiaCarbonatite
DS2003-0022
2003
Gomes, C.B.Antonini, P., Conim Chiaramonti, P., Gomes, C.B., Censi, P., Riffel, B.F.The Early Proterozoic carbonatite complex of Angico dos Dias, Bahia State, Brazil:Mineralogical Magazine, Vol. 67, 5, pp. 1039-58.Brazil, BahiaCarbonatite, geochronology
DS200412-0043
2003
Gomes, C.B.Antonini, P., Comin-Chiaramonti, P., Gomes, C.B., Censi, P., Riffel, B.F., Yamamoto, E.The Early Proterozoic carbonatite complex of Angico dos Dias, Bahia State, Brazil: geochemical and Sr Nd isotopic evidence for aMineralogical Magazine, Vol. 67, 5, pp. 1039-57.South America, BrazilGeochronology, carbonatites
DS200812-0978
2008
Gomes, C.B.Ruberti, E., Enrich, G.E.R., Gomes, C.B., Comin-Charamonti, P.Hydrothermal REE fluorocarbonate mineralization at Barra do Itapirapua, a multiple stockwork carbonatite, southern Brazil.Canadian Mineralogist, Vol. 46, 4, August pp.South America, BrazilCarbonatite
DS200912-0123
2009
Gomes, C.B.Comin-Chiaramonti, P., Lucassen, P., Girardi, V.A.V., De Min, A., Gomes, C.B.Lavas and their mantle xenoliths from intracratonic eastern Paraguay( South American Platform) and Andean domain NW Argentina: a comparative review.Mineralogy and Petrology, in press availableSouth America, Paraguay, ArgentinaXenoliths
DS201012-0116
2009
Gomes, C.B.Comin-Chiaramonti, P., Lucassen, F., Girardi, V.A.V., De Min, A., Gomes, C.B.Lavas and their mantle xenoliths from intracratonic Eastern Paraguay ( South American Platform) and Anean Domain, NW Argentina: a comparative review.Mineralogy and Petrology, Vol. 98, 1-4, pp. 143-165.South America, Paraguay, ArgentinaXenoliths
DS201012-0460
2010
Gomes, C.B.Lustrino, M., Marazzo, M., Melluso, L., Tassinari, C.C.G., Brotzu, P., Gomes, C.B., Morbidelli, RubertiPetrogenesis of early Cretaceous silicic volcanism in se Uruguay: the role of mantle and crustal sources.Geochemical Journal, Vol. 44, 1, pp. 1-22.South America, UruguayRhyolites - not specific diamonds - backgrounder
DS201112-0378
2011
Gomes, C.B.Gomes, C.B., Ruberti, E., Comin-Chiaramonti, P., Azzone, R.G.Alkaline magmatism in the Ponta Grossa Arch, SE Brazil: a review.Journal of South American Earth Sciences, Vol. 32, 2, pp. 152-168.South America, BrazilAlkaline rocks, magmatism, carbonatite
DS201112-0379
2011
Gomes, C.B.Gomes, C.B., Velaquez, V.F., Azzone, R.G., Paula, G.S.Alkaline magmatism in the Amambay area, NE Paraguay: the Cerro Sarambi complex.Journal of South American Earth Sciences, Vol. 32, 1, pp. 75-95.South America, ParaguayMagmatism - not specific to diamonds
DS201112-0884
2011
Gomes, C.B.Ruberti, E., Enrich, G.E.R., Azzone, R.G., Comin-Chiaramonti, P., De Min, A., Gomes, C.B.The Banhadao alkaline complex, southeastern Brazil: source and evolution of potassic SiO2 undersaturated high Ca and low Ca magmatic series.Mineralogy and Petrology, In press available,South America, BrazilAlkalic
DS201212-0605
2012
Gomes, C.B.Ruberti, E., Enrich, G.E.R., Azzone, R.G., Comin-Chiaramonti, P., De Min, A., Gomes, C.B.The Banhadao alkaline complex, southeastern Brazil: source and evolution of potassic SiO2 undersaturated high Ca and low Ca magmatic series.Mineralogy and Petrology, Vol. 104, 1-2, pp. 63-80.South America, BrazilAlkalic
DS201312-0199
2013
Gomes, C.B.De Min, A., Hendriks, B., Siejko, F., Comin-Chiaramonti, P., Girardi, V., Ruberti, E., Gomes, C.B., Neder, R.D., Pinho, F.C.Age of ultramafic high K rocks from Planalto da Serra ( Mato Grosso, Brazil).Journal of South American Earth Sciences, Vol. 41, pp. 57-64.South America, BrazilGeochronology
DS201504-0191
2015
Gomes, C.B.Comin-Chiaramonti, P., Gomes, C.B., De Min, A., Ernesto, M., Gasparon, M.Magmatism along the high Paraguay River at the border of Brazil and Paraguay: a review and new constraints on emplacement ages.Journal of South American Earth Sciences, Vol. 58, March pp. 72-81.South America, Paraguay, BrazilGeochronology

Abstract: The magmatic rocks from Alto Paraguay (High Paraguay River extensional lineament), western Apa craton, mainly consist of several major circular alkaline complexes and some rhyolitic domes and ignimbrites. The former are characterized by intrusive Na-alkaline rock-types (nepheline syenites and syenites and effusive equivalents) topped by lava flows and ignimbrites. Two main evolved suites were defined using petrochemical and Sr- isotope data: an agpaitic suite in the north and a miaskitic suite in the south. The domes of subalkaline rhyolitic lavas and ignimbrites occur to the north of the alkaline complexes, along the Paraguay River, near the town of Fuerte Olimpo. The emplacement ages of the alkaline complexes were constrained using the K-Ar, Ar-Ar, Rb-Sr and Sm-Nd dating methods on whole rocks and/or mineral separates (amphibole, alkali feldspar and biotite). Ages are quite variable (Upper Permian to Middle Triassic), with average K-Ar and Ar-Ar ages of 248.8 ± 4.8 and 241.8 ± 1.1 Ma, respectively, and Rb-Sr and Sm-Nd age data giving best values from 248 ± 4 to 244 ± 27 Ma and from 256 ± 3 to 257 ± 3 Ma, respectively. In contrast, the Fuerte Olimpo volcanics show a Mesoproterozoic age (1.3 Ga, K-Ar and Ar-Ar radiometric methods; and 1.42 ± 0.24 to 1.30 ± 0.03 Ga, Rb-Sr and Sm-Nd methods, respectively). Rb-Sr systematics (87Sr/86Sr initial ratios ? 0.7038) highlight a relatively "primitive" character of the Na-alkaline magmatic source(s), in contrast with the "crustal" values (87Sr/86Sr initial ratio ? 0.7105) of the Fuerte Olimpo rhyolites. Thus, magmatism in the Alto Paraguay area is related to two extensional events: a younger event corresponding to the Permian-Triassic alkaline rocks, and an older event connected to the Precambrian volcanic acidic rocks.
DS201609-1712
2016
Gomes, C.B.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.
DS201702-0199
2016
Gomes, C.B.Castillo Clerici, A.M., Gomes, C.B., De Min, A., Comin-Chiaramonti, P.Heavy minerals in the sediments from Paraguay rivers as indicators for diamond occurrences. IN Port**Boletin del Museo Nacional de Historia Narural del Paraguay, Vol. 20, 2, pp. 188-204. pdf available in * PortSouth America, ParaguayGeochemistry - indicator minerals

Abstract: Many diamondiferous kimberlites in the Lac de Gras region of the Northwest Territories are concealed by glacial drift, rendering them challenging to detect by traditional exploration techniques that exploit residual surface chemistry. Much research has been aimed at the development of deep penetrating geochemical exploration technologies to increase the rate of discovery whilst reducing risk and exploration cost. However, results from a detailed study of soil geochemistry above the DO-18 kimberlite (Peregrine Diamonds) demonstrate the potential to apply conventional surface geochemical techniques coupled with surface material mapping and landscape evolution models to the evaluation of discrete targets. 50 soil samples from the oxidized upper B-horizon in a detailed grid crossing the concealed kimberlite were collected. Samples, screened to -180 microns, were analysed by multi-element ICP-MS following 4-acid, aqua-regia and deionized water extractions. Fp-XRF was utilised as an equivalent total method to evaluate its applicability. Sequential leach on selected samples was undertaken to understand the deportment of the elements of interest within the soils. Surficial mapping included soil type, topographic variation, landforms, environment and vegetation. This allows an assessment of surface controls on the geochemistry, in particular the generation of false anomalies from chemical traps such as swamps; and allows the generation of a landscape development model. Hydrocarbons, analysed using the SGH and Gore-sorber techniques, were evaluated to characterize the type and abundance of complex hydrocarbons above the kimberlite relative to above the host granitic gneiss. Geochemical data is subject to landform generation processes. The northern half of the grid comprises till with numerous frost boils. The southern half, at lower topography below a distinct break, is dominated by sand-rich material and fine clay. Results from the 4-acid and aqua regia extraction show a dispersion of Nb, Ni, Mg, Ce, Cr and Cs from directly above the northern part of the kimberlite to the edge of the sampling grid, approximately 500 metres to the northwest, following glacial dispersion. SGH-hydrocarbon results exhibit a similar pattern in light-alkyl benzenes. Fp-XRF data repeats the pattern in all elements except Mg, where the concentrations are too low for reliable detection. In the southern half of the grid, at a lower topographic level, geochemical responses are considerably more subtle. It is hypothesised that anomaly formation in the till followed standard glacial dispersion in the down ice trend. Material was entrained to the surface from deeper in the till, locally above the kimberlite, by frost boil action. The southern part of the area is considered to have been inundated with water, the remains of which comprise the current lake over the DO-27 kimberlite approximately 400m to the south. Sediments in this area are clay rich - comprising material deposited by the lake, or re-worked sandy material along the palaeo-lake margin and subsequent erosional channels. These later processes acted to further disperse, conceal and dilute the signal of the underlying body.
DS202011-2034
2016
Gomes, C.B.Castillo Clerici, A.M., Gomes, C.B., De Min, A., Comin-Chiaramonti, P.Heavy minerals in the sediments from Paraguay rivers as indicators for diamonds occurrences. *** NOTE DATEBol. Mus. Nac. Hist. Parag. *** ENG, Vol. 20, 2, pp. 188-204. pdfSouth America, Paraguaygeochemistry

Abstract: After some works of Jaime Baez-Presse that quoted the presence of diamonds in Eastern Paraguay, we have perfprmed a whole sampling a study relative to the indicator mineral for diamonds. Indicator minerals are mineral species that, when appearing as transported grains in clastic sediments, indicate the presence in bedrock of a specific type of mineralization, hydrothermal alteration or lithology. Their physical and chemical characteristics, including a relatively high density (heavy minerals), facilitate their preservation and identification. The heavy minerals represent an important exploration method for detecting a variety of ore deposit types including diamond, gold, Ni-Cu, PGE, and so on.. One of the most significant events in the application of indicator mineral methods in the past was the diamond exploration. This paper provides an overview of indicator mineral methods, i.e. presence of Cr-diopside, Pyrope-rich garnet and Picroilmenite, for diamond exploration along the Eastern Paraguay river. Unfortunately the above heavy mineraks, generally associated to the diamonds, do not appear in Eastern Paraguay, excluding this Country as a potential source for the diamond as economic potential source.
DS202010-1833
2020
Gomes, C.B.. De MinClerici, A.M.C., Gomes, C.B.. De Min, A., Comin-Chiaramnti, P.Heavy minerals in the sediments from Paraguay rivers as indicators for diamond occurrences.Bol. Mus. Nac. Hist. Paraguay, , Vol. 20, 2, pp. 188-204. pdfSouth America, Paraguaygeochemistry

Abstract: After some works of Jaime Baez-Presse that quoted the presence of diamonds in Eastern Paraguay, we have perfprmed a whole sampling a study relative to the indicator mineral for diamonds. Indicator minerals are mineral species that, when appearing as transported grains in clastic sediments, indicate the presence in bedrock of a specific type of mineralization, hydrothermal alteration or lithology. Their physical and chemical characteristics, including a relatively high density (heavy minerals), facilitate their preservation and identification. The heavy minerals represent an important exploration method for detecting a variety of ore deposit types including diamond, gold, Ni-Cu, PGE, and so on.. One of the most significant events in the application of indicator mineral methods in the past was the diamond exploration. This paper provides an overview of indicator mineral methods, i.e. presence of Cr-diopside, Pyrope-rich garnet and Picroilmenite, for diamond exploration along the Eastern Paraguay river. Unfortunately the above heavy mineraks, generally associated to the diamonds, do not appear in Eastern Paraguay, excluding this Country as a potential source for the diamond as economic potential source.
DS201412-0244
2014
Gomes, J.Fernandes, A.F., Karfunkel, J., Hoover, D.B., Sgarbi, G.N.C., Walde, D., Gomes, J., Kambrock, K.O garimpo Canastrel, Coromandel-MG: ocorrencia de diamante no conglomerado cretaceo do grupo Mat a de Corda.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractSouth America, Brazil, Minas GeraisDeposit - Coromandel
DS201501-0008
2014
Gomes, J.C.de S.P.Fernandes, A.F., Karfunkel, J., Hoover, D.B., Sgarbi, P.B.De Al., Sgarbo, G.N.C., Oliveira, G.D., Gomes, J.C.de S.P., Kambrock, K.The basal conglomerate of the Capacete Formation ( Mat a da Corda Group) and its relation to diamond distributions in Coromandel, Minas Gerais State, Brazil.Brazil Journal of Geology, Vol. 44, 1, pp. 91-103.South America, BrazilCoromandel district

Abstract: The diamond bearing district of Coromandel is located in the northwestern part of Minas Gerais, within the Alto Paranaíba Arch, famous for the discovery of most of Brazil's large diamonds above 100 ct. Detailed mapping, aimed at characterizing the Mata da Corda Group of Upper Cretaceous age of Coromandel, has been carried out. This Group was divided into the Patos Formation, composed of kimberlitic and kamafugitic rocks, and the Capacete Formation, presented by conglomerates, pyroclastic rocks, arenite and tuffs. Exposures of the latter Formation have been studied in detail at the small abandoned mine called Canastrel, as well as in the headwater of Santo Antônio do Bonito River. The results have been compared to studies of the kimberlite bodies in the nearby Douradinho River. Kimberlite indicator minerals from these localities show the same compositional trend. Moreover, in the basal conglomerate of the Garimpo Canastrel two diamonds diamonds have been recovered and described. The Garimpo Wilson, situated in the headwater of the river Santo Antônio do Bonito in paleo-alluvium, is composed of material exclusively derived from the erosion of the Capacete Formation and Precambrian (sterile) Canastra quartzites and schists. These detailed investigations suggest that the basal conglomerates of the Capacete Formation represent the main source rock of the alluvial diamond deposits in the Coromandel region.
DS1981-0184
1981
Gomes, J.M.Gomes, J.M., Martinez, G.M.Recovery of Gold and Other Heavy Minerals from Alluvial Deposits: Equipment and Practices.Reno Research Center, United States Bureau of Mines, 22P.United States, California, Oregon, Nevada, West Coast, Rocky MountainsDiamonds, Techniques, Sampling, Mineral Processing
DS1975-0635
1977
Gomes, J.P.Svisero, D.P., Gomes, J.P.Composiction Y Origen de Inclusiones Minerales En Diamantesde Venezuela.Fith. Congreso Geologico Venezolano, PP. 1.219-1.234.South America, VenezuelaDiamond Inclusions, Analyses, Rio Caroni, Quebrada Grande
DS201506-0270
2015
Gomes de Moraes Rocha, L.Gomes de Moraes Rocha, L., Bittencourt Pires, A.C., Chatck Carmelo, A., Oksum, E.Curie surface of the alkaline provinces of Goias (GAP) and Alto Paranaiba ( APAP), central Brazil.Journal of Volcanology and Geothermal Research, Vol. 297, pp. 28-38.South America, BrazilKimberlites, Lineaments
DS201608-1410
2015
Gomes dos Santis, E.Gomes dos Santis, E.The Kimberley Process Certification System - KPCS and diamond production changes in selected African Countries.REM: Revista Escola de Minas, Vol. 68, 3, pp. 279-285.AfricaKimberley Process

Abstract: After more than a decade since its creation, the KPCS is undergoing questioning as to efficiency in combating the irregular trade of diamonds, among the countries with significant production for the global market, mainly Angola, the Democratic Republic of the Congo and Zimbabwe. Governments and institutions are considering it to be conducive to serious violations of human rights. In Brazil all activities of the sector have been reduced drastically. It is estimated that there has been a loss in Brazilian production, after implementation of the KPCS rules, in the order of 8.1 million Kts, valued at more than $ 2.0 billion.
DS2000-0347
2000
Gomez, F.Gomez, F., Beauchamp, W., Barazangi, M.Role of the Atlas Mountains (northwest Africa) within the African Eurasian plate boundary zone.Geology, Vol. 28, No. 9, Sept. pp. 775-8.Africa, North Africa, MoroccoTectonics
DS200612-0385
2006
Gomez, F.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
DS1981-0185
1981
Gomez, J.B.Gomez, J.B.Diamonds in Venezuela: Geo-economic Importance and Problems. *spaGeominas, *SPA., Vol. 10, pp. 60-64VenezuelaEconomics
DS1993-0332
1993
Gomez Valenca, J.De Albuquerque Scarbi, P.B., Gomez Valenca, J.Kasilite in Brazilian kamafugitic rocksMineralogical Magazine, Vol. 57, No. 386, March pp. 165-171BrazilUltramafic, Mineralogy
DS202106-0937
2021
Gomez-Arias, A.Gomez-Arias, A., Yesares, L., Carabello, M.A., Maleke, M., Vermeulen, D., Nieto, J.M., van Heerden, E., Castillo, J.Environmental and geochemical characterization of alkaline mine wastes from Phalaborwa ( Palabora) complex, South Africa.Journal of Geochemical Exploration, Vol. 224, 106757, 13p. PdfAfrica, South Africadeposit - Palabora

Abstract: A detailed characterization of alkaline tailing ponds and waste rock dumps from Phalaborwa Igneous Complex (PIC) South Africa, has been accomplished. The study goes beyond the environmental characterization of mining wastes, offering the first insight towards the recycling of the wastes as alkaline reagent to neutralize acid industrial wastewater. To achieve these aims, tailings and waste rocks were characterized using a combination of conventional, novel and modified Acid Rock Drainage (ARD) prediction methodologies, as well as South African leachate tests, sequential extractions and pseudo-total digestions. The scarcity of Fe-sulphide minerals and the abundance of alkaline minerals indicated that PIC wastes are not ARD producers. The highest neutralization potential was found in the carbonatite rocks and East tailing samples (range between 289 and 801 kg CaCO3 eq/t). According to the National Environmental Management Waste Act (59/2008) of South Africa, tailing ponds and waste rock dumps from PIC classify as non-hazardous (Type 3 waste). The sequential extractions showed that the different fractions from most of the samples would mostly release sulphate and non-toxic elements, such as Ca, Mg, Na and K, which might be a concern if leached in high concentration. In addition, relatively high concentrations of radionuclides, such as U and Th (average of 6.7 and 36.3 mg/kg, respectively) are present in the non-labile fraction of PIC wastes, while the leachable concentrations were always below 0.006 mg/L. Among PIC wastes, East tailing would be the best option as alkaline reagent to neutralize acid wastewater because of its high neutralization potential and non-harmful leachate composition. In general, this study exposes the shortcomings in mine waste characterization, particularly for alkaline mine wastes, and introduces the assessment of potential revalorization as a novel practice in mine waste characterization that, if extended as a regular practice, would facilitate a circular economy approach to the mining industry with its consequent economic and environmental benefits.
DS201312-0741
2013
Gomez-Sanchez, M.E.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
DS1990-1293
1990
Gomi, K.Saito, Y., Sato, K., Gomi, K., Miyadera, H.Diamond synthesis from CO-H2 mixed gas plasmaJournal of Material Science, Vol. 25, No. 28, February pp. 1246-1250GlobalDiamond synthesis, Gas plasma
DS201312-0319
2013
Gomide, C.S.Gomide, C.S., Brod, J.A., Junqueira-Brod, T.C., Buhn, B.M., Santos, R.V., Barbosa, E.S.R., Cordeiro, P.F.O., Palmieri, M., Grasso, C.B., Torres, M.G.Sufur isotopes from Brazilian alkaline carbonatite complexes.Chemical Geology, Vol. 341, pp. 38-49.South America, BrazilDeposit - Tapira, Salitre, Serra Negra, Catalao, Jacupiringa
DS1960-0672
1966
Gomon, G.O.Gomon, G.O.Almazy. #2Leningrad:, 145P.RussiaKimberlite, Kimberley, Janlib, Diamond
DS1991-0586
1991
Gonazales Bonorino, G.Gonazales Bonorino, G.Late Paleozoic orogeny in the northwestern Gondwana continental margin, western Argentin a and ChileJournal of South American Earth Sciences, Vol. 4, No. 1/2, pp. 131-144Argentina, ChileTectonics -orogeny, Gondwana
DS2002-1677
2002
GoncalvesWaerenborgh, J.C., Figueoras, J., Mateus, Goncalves57Fe Mossbauer spectroscopy study of the correlation between Fe3+content and magnetic properties Cr spinelsEuropean Journal of Mineralogy, Vol.14,2,pp.437-46.GlobalSpectroscopy, Chrome spinels
DS201212-0590
2012
Goncalves, A.Robles-Cruz, S.E., Escayola, M., Jackson, S., Gali, S., Pervov, S., Watanga, M., Goncalves, A., Melgarejo, J.C.U-Pb SHRIMP geochronology of zircon from the Catoca kimberlite, Angola: implications for diamond exploration.Chemical Geology, Vol. 310-311, pp. 137-147.Africa, AngolaDeposit - Catoca
DS201112-0055
2011
Goncalves, A.O.Bambi, A.C.J.M., Costanzo, A., Melgarejo, J.C., Goncalves, A.O., Neto, A.B.Evolution of pyrochlore in pluonic carbonatites: the Tchivira Complex case, Angola.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterAfrica, AngolaCarbonatite
DS201112-0056
2011
Goncalves, A.O.Bambi, A.C.J.M., Costanzo, A., Melgarejo, J.C., Goncalves, A.O., Neto, A.B.Evolution of pyrochlore in plutonic carbonatites: the Tchivira complex case, Angola.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.93-95.Africa, AngolaTchivira
DS201112-0057
2011
Goncalves, A.O.Bambi, A.C.J.M., Costanzo, A., Melgarejo, J.C., Goncalves, A.O., Neto, A.B.Evolution of pyrochlore in plutonic carbonatites: the Tchivira complex case, Angola.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.93-95.Africa, AngolaTchivira
DS201212-0050
2012
Goncalves, A.O.Bambi, A.C.J.M., Costanzo, A., Goncalves, A.O., Melgareto, J.C.Tracing the chemical evolution of primary pyrochlore from plutonia to volcanic carbonatites: the role of fluorine.Mineralogical Magazine, Vol. 76, 2, pp. 377-392.TechnologyCarbonatite, chemistry
DS201212-0460
2012
Goncalves, A.O.Melgarejo, J.C., Costanzo, A., Bmbi, A.C.J.M., Goncalves, A.O., Neto, A.B.Subsolidus processes as a key factor on the distribution of Nb species in plutonic carbonatites: the Tchivira case, Angola.Lithos, Vol. 152, pp. 187-201.Africa, AngolaCarbonatite
DS201212-0732
2012
Goncalves, A.O.Torro, L., Villanova, C., Castillo, M., Campeny, M., Goncalves, A.O., Melgarejo, J.C.Niobium and rare earth minerals from the Virulundo carbonatite, Namibe, Angola.Mineralogical Magazine, Vol. 76, 2, pp. 393-409.Africa, AngolaDeposit - Virulundo
DS201509-0387
2015
Goncalves, A.O.Campeny, M., Kamenetsky, V.S., Melgarejo, J.C., Mangas, J., Manuel, J., Alfonso, P., Kamenetsky, M.B., Bambi, A.C.J.M., Goncalves, A.O.Carbonatitic lavas in CatAnd a ( Kwanza Sul, Angola): mineralogical and geochemical constraints on the parental melt.Lithos, Vol. 232, pp. 1-11.Africa, AngolaCarbonatite

Abstract: A set of small volcanic edifices with tuff ring and maar morphologies occur in the Catanda area, which is the only locality with extrusive carbonatites reported in Angola. Four outcrops of carbonatite lavas have been identified in this region and considering the mineralogical, textural and compositional features, we classify them as: silicocarbonatites (1), calciocarbonatites (2) and secondary calciocarbonatites produced by the alteration of primary natrocarbonatites (3). Even with their differences, we interpret these lava types as having been a single carbonatite suite related to the same parental magma. We have also estimated the composition of the parental magma from a study of melt inclusions hosted in magnetite microphenocrysts from all of these lavas. Melt inclusions revealed the presence of 13 different alkali-rich phases (e.g., nyerereite, shortite, halite and sylvite) that argues for an alkaline composition of the Catanda parental melts. Mineralogical, textural, compositional and isotopic features of some Catanda lavas are also similar to those described in altered natrocarbonatite localities worldwide such as Tinderet or Kerimasi, leading to our conclusion that the formation of some Catanda calciocarbonatite lavas was related to the occurrence of natrocarbonatite volcanism in this area. On the other hand, silicocarbonatite lavas, which are enriched in periclase, present very different mineralogical, compositional and isotopic features in comparison to the rest of Catanda lavas. We conclude that its formation was probably related to the decarbonation of primary dolomite bearing carbonatites.
DS201711-2506
2017
Goncalves, A.O.Castillo-Oliver, M., Melgarejo, J.C., Gali, S., Pervov, V., Goncalves, A.O., Griffin, W.L., Pearson, N.J., O'Reilly, S.Y.Use and misuse of Mg- and Mn- rich ilmenite in diamond exploration: a petrographic and trace element approach. Congo-Kasai cratonLithos, Vol. 292-293, pp. 348-363.Africa, Angoladeposit - CAT115, Tchiuzo

Abstract: Magnesian ilmenite is a common kimberlite indicator mineral, although its use in diamond exploration is still controversial. Complex crystallisation and replacement processes have been invoked to explain the wide compositional and textural ranges of ilmenite found in kimberlites. This work aims to shed light on these processes, as well as their implications for diamond exploration. Petrographic studies were combined for the first time with both major- and trace-element analyses to characterise the ilmenite populations found in xenoliths and xenocrysts in two Angolan kimberlites (Congo-Kasai craton). A multi-stage model describes the evolution of ilmenite in these pipes involving: i) crystallisation of ferric and Mg-rich ilmenite either as metasomatic phases or as megacrysts, both in crustal and in metasomatised mantle domains; ii) kimberlite entrainment and xenolith disaggregation producing at least two populations of ilmenite nodules differing in composition; iii) interaction of both types with the kimberlitic magma during eruption, leading to widespread replacement by Mg-rich ilmenite along grain boundaries and fractures. This process produced similar major-element compositions in ilmenites regardless of their primary (i.e., pre-kimberlitic) origin, although the original enrichment in HFSE (Zr, Hf, Ta, Nb) observed in Fe3 +-rich xenocrysts is preserved. Finally (iv) formation of secondary Mn-ilmenite by interaction with a fluid of carbonatitic affinity or by infiltration of a late hydrothermal fluid, followed in some cases by subsolidus alteration in an oxidising environment. The complexities of ilmenite genesis may lead to misinterpretation of the diamond potential of a kimberlite during the exploration stage if textural and trace-element information is disregarded. Secondary Mg-enrichment of ilmenite xenocrysts is common and is unrelated to reducing conditions that could favour diamond formation/preservation in the mantle. Similarly, Mn-rich ilmenite should be disregarded as a diamond indicator mineral, unless textural studies can prove its primary origin.
DS201801-0017
2017
Goncalves, A.O.Giuliani, A., Campeny, M., Kamenetsky, V.S., Afonso, J.C., Maas, R., Melgarejo, J.C., Kohn, B.P., Matchen, E.L., Mangas, J., Goncalves, A.O., Manuel, J.Southwestern Africa on the burner: Pleistocene carbonatite volcanism linked to deep mantle upwelling in Angola.Geology, Vol. 45, 11, pp. 971=974.Africa, Angolacarbonatite - Catanda

Abstract: The origin of intraplate carbonatitic to alkaline volcanism in Africa is controversial. A tectonic control, i.e., decompression melting associated with far-field stress, is suggested by correlation with lithospheric sutures, repeated magmatic cycles in the same areas over several million years, synchronicity across the plate, and lack of clear age progression patterns. Conversely, a dominant role for mantle convection is supported by the coincidence of Cenozoic volcanism with regions of lithospheric uplift, positive free-air gravity anomalies, and slow seismic velocities. To improve constraints on the genesis of African volcanism, here we report the first radiometric and isotopic results for the Catanda complex, which hosts the only extrusive carbonatites in Angola. Apatite (U-Th-Sm)/He and phlogopite 40Ar/39Ar ages of Catanda aillikite lavas indicate eruption at ca. 500-800 ka, more than 100 m.y. after emplacement of abundant kimberlites and carbonatites in this region. The lavas share similar high-? (HIMU)-like Sr-Nd-Pb-Hf isotope compositions with other young mantle-derived volcanics from Africa (e.g., Northern Kenya Rift; Cameroon Line). The position of the Catanda complex in the Lucapa corridor, a long-lived extensional structure, suggests a possible tectonic control for the volcanism. The complex is also located on the Bié Dome, a broad region of fast Pleistocene uplift attributed to mantle upwelling. Seismic tomography models indicate convection of deep hot material beneath regions of active volcanism in Africa, including a large area encompassing Angola and northern Namibia. This is strong evidence that intraplate late Cenozoic volcanism, including the Catanda complex, resulted from the interplay between mantle convection and preexisting lithospheric heterogeneities.
DS201903-0502
2019
Goncalves, A.O.da Silva, B.V., Hackspacher, P.C., Siqueira Riberio, M.C., Glasmacher, U.A., Goncalves, A.O., Doranti-Tiritan, C., de Godoy, D.F., Constantino, R.R.Evolution of the southwestern Angolan margin: episodic burial and exhumation is more realistic than long term denudation.International Journal of Earth Sciences, Vol. 108, pp. 89-113.Africa, Angolathermochronology

Abstract: There are two main points of view regarding how continental margins evolve. The first one argues that the present-day margins have been developed by long-term denudation since a major exhumation episode, probably driven by rifting or another relevant tectonic event. The second one argues that continental margins underwent alternating burial and exhumation episodes related to crustal tectonic and surface uplift and subsidence. To demonstrate that the proximal domain of the southwestern Angolan margin has evolved in a polycyclic pattern, we present a review of geological and thermochronological information and integrate it with new combined apatite fission-track and (U-Th)/He data from Early Cretaceous volcanic and Precambrian basement samples. We also provide hypotheses on the possible mechanisms able to support the vertical crustal movements of this margin segment, which are also discussed based on some modern rifting models proposed for Central South Atlantic. The central apatite fission-track ages range from 120.6?±?8.9 to 272.9?±?21.6 Ma, with the mean track lengths of approximately 12 µm. The single-grain apatite (U-Th)/He ages vary between 52.2?±?1 and 177.2?±?2.6 Ma. The integration of the thermochronological data set with published geological constraints supports the following time-temperature evolution: (1) heating since the Carboniferous-Permian, (2) cooling onset in the Early Jurassic, (3) heating onset in the Early Cretaceous, (4) cooling onset in the Mid- to Late Cretaceous, (5) heating onset in the Late Cretaceous, and (6) cooling onset in the Oligocene-Miocene. The thermochronological data and the geological constraints, support that the proximal domain of the southwestern Angolan margin was covered in the past by pre-, syn-, and post-rift sediments, which were eroded during succeeding exhumation events. For this margin segment, we show that a development based on long-term denudation is less realistic than one based on burial and exhumation episodes during the last 130 Myr.
DS201012-0632
2010
Goncalves, O.A.Robles-Cruz, S.E., Escayola, M., Melgarejo, J.C., Watangua, M., Gali, S., Goncalves, O.A., Jackson, S.Disclosed dat a from mantle xenoliths of Angolan kimberlites based on LA-ICP-MS analyses. Catoca and Cucumbi-79International Mineralogical Association meeting August Budapest, abstract p. 553.Africa, AngolaPetrology
DS201012-0791
2010
Goncalves, O.A.Torro, L., Villanova, C., Castillo, M., Campeny, M., Goncalves, O.A., Melgarejo, J.C.Nb and REE minerals from the Virulundo carbonatite Namibe, Angola.International Mineralogical Association meeting August Budapest, abstract p. 578.Africa, AngolaCarbonatite
DS200712-0047
2007
Goncalves, P.Baldwin, J.A., Powell, R., Williams, M.L., Goncalves, P.Formation of eclogite and reaction during exhumation to mid-crustal levels, Snowbird Tectonic zone, Western Canadian Shield.Journal of Metamorphic Geology, Vol. 25, 9, pp. 953-974.Canada, Saskatchewan, AlbertaEclogite
DS201603-0426
2016
Goncalves, P.Thiery, V., Rolin, P., Dubois, M., Caumon, M-C., Goncalves, P.Reply: Discovery of metamorphic microdiamonds from the parautochthonous units of the Variscan French Massif Central: comment.Gondwana Research, in press available 2p.EuropeMicrodiamonds
DS1984-0473
1984
Goncharenko, A.I.Makeev, A.B., Agafanov, L.V., Goncharenko, A.I.The Relation of the Chemical Composition to the Physical Properties of Chrome Spinels in Alpinotypic Ultrabasites.Soviet Geology And Geophysics, Vol. 25, No. 2, PP. 125-129.RussiaMineral Chemistry
DS1993-0557
1993
Goncharenko, A.I.Goncharenko, A.I., Fomin, Yu.A.Oxygen isotope distribution in plastically deformed and recrystallized olivine from Alpine type ultramaficsDoklady Academy of Sciences USSR, Earth Science Section, Vol. 317, pp. 207-210RussiaGeochronology, Ultramafics
DS202201-0027
2021
GoncharovMukakami, M., Goncharov, A,F., Miyajimac, N., Yamazakid, D., Holtgrewe, N.Radiative thermal conductivity of single-crystal bridgmanite at the core-mantle boundary with implications for thermal evolution of the Earth.Earth and Planetary Science Letters, Vol. 578, 9p. PdfMantlebridgmanite

Abstract: The Earth has been releasing vast amounts of heat from deep Earth's interior to the surface since its formation, which primarily drives mantle convection and a number of tectonic activities. In this heat transport process the core-mantle boundary where hot molten core is in direct contact with solid-state mantle minerals has played an essential role to transfer thermal energies of the core to the overlying mantle. Although the dominant heat transfer mechanisms at the lowermost mantle is believed to be both conduction and radiation of the primary lowermost mantle mineral, bridgmanite, the radiative thermal conductivity of bridgmanite has so far been poorly constrained. Here we revealed the radiative thermal conductivity of bridgmanite at core-mantle boundary is substantially high approaching to ?5.3±1.2 W/mK based on newly established optical absorption measurement of single-crystal bridgmanite performed in-situ under corresponding deep lower mantle conditions. We found the bulk thermal conductivity at core-mantle boundary becomes ?1.5 times higher than the conventionally assumed value, which supports higher heat flow from core, hence more vigorous mantle convection than expected. Results suggest the mantle is much more efficiently cooled, which would ultimately weaken many tectonic activities driven by the mantle convection more rapidly than expected from conventionally believed thermal conduction behavior.
DS1998-0520
1998
Goncharov, A.Goncharov, A., et al.Average composition of the crust in the Australian, Fennoscandianvian and Ukrainian shields from refractionAgso News, No. 28, May pp. 20-23.Australia, Scandinavia, Norway, Finland, SwedenGeochemistry - crust
DS1998-0521
1998
Goncharov, A.Goncharov, A., Drummond, B., Tripolsky, A., Wyborn, L.Average composition of the crust in the Australian, Fennoscandian and Ukrainian shields from refraction..Agso Research Newsletter, No. 28, May pp. 20-23Australia, Ukraine, Norway, Finland, SwedenGeophysics - seismics, Petrology
DS2000-0786
2000
Goncharov, A.Pylypenko, V., Goncharov, A.Seismic migration in near vertical and wide angle relection and refractionstudies: to unified approach.Exploration Geophysics, ASEG Bulletin, Vol. 31, No. 3, Sept. pp. 461-68.AustraliaGeophysics - seismics, Seismic migration - not specific to diamonds
DS201312-0651
2013
Goncharov, A.Nimis, P., Goncharov, A., Ionov, D.Fe3 partitioning systematics between orthopyroxene and garnet in well equilibriated mantle xenoliths.Goldschmidt 2013, AbstractRussia, MongoliaUdachnaya, Obnazhennaya, Dariganaga
DS201502-0088
2015
Goncharov, A.Nimis, P., Goncharov, A., Ionov, D.A., McCammon, C.Fe3 partitioning systematics between orthopyroxene and garnet in mantle peridotite xenoliths and implications for thermobarometry of oxidized and reduced mantle rocks.Contributions to Mineralogy and Petrology, Vol. 169, 6p.MantlePeridotite
DS201606-1100
2016
Goncharov, A.Kopylova, M.G., Beausoleil, Y., Goncharov, A., Burgess, J., Strand, P.Spatial distribution of eclogite in the Slave Craton mantle: the role of subduction.Tectonophysics, Vol. 672-673, pp. 87-103.Canada, Northwest TerritoriesSubduction

Abstract: We reconstructed the spatial distribution of eclogites in the cratonic mantle based on thermobarometry for ~ 240 xenoliths in 4 kimberlite pipes from different parts of the Slave craton (Canada). The accuracy of depth estimates is ensured by the use of a recently calibrated thermometer, projection of temperatures onto well-constrained local peridotitic geotherms, petrological screening for unrealistic temperature estimates, and internal consistency of all data. The depth estimates are based on new data on mineral chemistry and petrography of 148 eclogite xenoliths from the Jericho and Muskox kimberlites of the northern Slave craton and previously reported analyses of 95 eclogites from Diavik and Ekati kimberlites (Central Slave). The majority of Northern Slave eclogites of the crustal, subduction origin occurs at 110-170 km, shallower than in the majority of the Central Slave crustal eclogites (120-210 km). The identical geochronological history of these eclogite populations and the absence of steep suture boundaries between the central and northern Slave craton suggest the lateral continuity of the mantle layer relatively rich in eclogites. We explain the distribution of eclogites by partial preservation of an imbricated and plastically dispersed oceanic slab formed by easterly dipping Proterozoic subduction. The depths of eclogite localization do not correlate with geophysically mapped discontinuities. The base of the depleted lithosphere of the Slave craton constrained by thermobarometry of peridotite xenoliths coincides with the base of the thickened lithospheric slab, which supports contribution of the recycled oceanic lithosphere to formation of the cratonic root. Its architecture may have been protected by circum-cratonic subduction and shielding of the shallow Archean lithosphere from the destructive asthenospheric metasomatism.
DS202110-1620
2021
Goncharov, A.Korolev, N., Nikitina, L.P., Goncharov, A.,Dubinina, E., Melnik, A.E., Muller, D., Chen, Y-X., Zinchenko, V.Three types of mantle eclogite from two layers of oceanic crust: a key case of metasomatically- aided transformation of low-to-high-magnesian eclogite.Journal of Petrology, 10.1093/petrology /egab070 98p. PdfAfrica, Angoladeposit - Catoca

Abstract: Reconstructed whole-rock and mineral major- and trace-element compositions, as well as new oxygen isotope data, for 22 mantle eclogite xenoliths from the Catoca pipe (Kasai Craton) were used to constrain their genesis and evolution. On the basis of mineralogical and major-element compositions, the Catoca eclogites can be divided into three groups: high-alumina (high-Al) (kyanite-bearing), low-magnesian (low-Mg#), and high-magnesian (high-Mg#) eclogites. The high-Al Catoca eclogites contain kyanite and corundum; high Al2O3 contents in rock-forming minerals; rare earth element (REE) patterns in garnets showing depleted LREEs, positive Eu anomalies (1.03-1.66), and near-flat HREEs; and high Sr contents in garnets and whole-rock REE compositions. All of these features point to a plagioclase-rich protolith (probably gabbro). Reconstructed whole-rock compositions (major elements, MREEs, HREEs, Li, V, Hf, Y, Zr, and Pb) and ?18O of 5.5-7.4‰ of the low-Mg# Catoca eclogites are in good agreement with the compositions of picrite basalts and average mid-ocean ridge basalt (MORB). The depleted LREEs and NMORB-normalised Nd/Yb values of 0.07-0.41 indicate that the degree of partial melting for the majority of the low-Mg# eclogites protolith was ?30%. The narrow ?18O range of 5.5-7.4‰ near the ‘gabbro-basalt’ boundary (6‰) obtained for the high-Al and low-Mg# Catoca eclogites reflects the influence of subduction-related processes. This case shows that mantle eclogites represented by two different lithologies and originating from different protoliths — plagioclase-rich precursor, presumably gabbro (for high-Al eclogites), and basalt (low-Mg# eclogites) — can provide similar and overlapping ?18O signatures on account of the influence of subduction-related processes. Chemical compositions of the high-Mg# eclogites indicate a complicated petrogenesis, and textural signatures reveal recrystallisation. The presence of Nb-rich rutile (8-12 wt% of Nb2O5) enriched with HFSE (Zr/Hf of 72.6-75.6) and multiple trace-element signatures (including reconstructed whole-rock NMORB-normalised Ce/Yb of 3.9-10.6 and Sr/Y of 5.8-9.6, MgO contents of 15.7-17.9 wt%, and high Ba and Sr) provide strong evidence for deep metasomatic alteration. High Cr contents in clinopyroxene (800-3740 ppm), garnet (430-1400 ppm), and accessory rutile (700-2530 ppm), together with extremely low Li contents of 1.0-2.4 ppm in clinopyroxene, may indicate hybridisation of the eclogites with peridotite. Comparison of the chemical compositions (major and trace elements) of (1) unaltered fresh cores of coarse-grained garnets from the low-Mg# eclogites, (2) secondary garnet rims (ubiquitous in the low-Mg# eclogites), (3) proto-cores in the coarse-grained garnet (high-Mg# eclogites), and (4) homogeneous recrystallised fine-grained garnets (high-Mg# eclogites) suggests that the high-Mg# eclogites formed through recrystallisation of low-Mg# eclogite in the presence of an external fluid in the mantle. Four of the five high-Mg# samples show that mantle metasomatism inside the Kasai craton mantle beneath the Catoca pipe occurred at a depth range of 145-160 km (4.5-4.8 GPa).
DS202112-1934
2021
Goncharov, A.Korolev, N., Nikitina, L.P., Goncharov, A., Dubinina, V.N., Melnik, A., Muller, D., Chen, Y-X., Zinchenko, V.N.Three types of mantle eclogite from two layers of oceanic crust: a key case of metasomatically-aided transformation of low-to-high-magnesian eclogite.Journal of Petrology, Vol. 62, 11, pp. 1-38. pdfAfrica, Angoladeposit - Catoca

Abstract: Reconstructed whole-rock (RWR) and mineral major- and trace-element compositions, as well as new oxygen isotope data, for 22 mantle eclogite xenoliths from the Catoca pipe (Kasai Craton) were used to constrain their genesis and evolution. On the basis of mineralogical and major-element compositions, the Catoca eclogites can be divided into three groups: high-alumina (high-Al) (kyanite-bearing), low-magnesian (low-Mg#), and high-magnesian (high-Mg#) eclogites. The high-Al Catoca eclogites contain kyanite and corundum; high Al2O3 contents in rock-forming minerals; rare earth element (REE) patterns in garnets showing depleted LREEs, positive Eu anomalies (1.03-1.66), and near-flat HREEs; and high Sr contents in garnets and whole-rock REE compositions. All of these features point to a plagioclase-rich protolith (probably gabbro). RWR compositions (major elements, MREEs, HREEs, Li, V, Hf, Y, Zr, and Pb) and ?18O of 5.5-7.4‰ of the low-Mg# Catoca eclogites are in good agreement with the compositions of picrite basalts and average mid-ocean ridge basalt (MORB). The depleted LREEs and NMORB-normalised Nd/Yb values of 0.07-0.41 indicate that the degree of partial melting for the majority of the low-Mg# eclogites protolith was ?30%. The narrow ?18O range of 5.5-7.4‰ near the ‘gabbro-basalt’ boundary (6‰) obtained for the high-Al and low-Mg# Catoca eclogites reflects the influence of subduction-related processes. This case shows that mantle eclogites represented by two different lithologies and originating from different protoliths—plagioclase-rich precursor, presumably gabbro (for high-Al eclogites), and basalt (low-Mg# eclogites)—can provide similar and overlapping ?18O signatures on account of the influence of subduction-related processes. Chemical compositions of the high-Mg# eclogites indicate a complicated petrogenesis, and textural signatures reveal recrystallisation. The presence of Nb-rich rutile (8-12 wt% of Nb2O5) enriched with high field strength elements (HFSE) (Zr/Hf of 72.6-75.6) and multiple trace-element signatures (including RWR, NMORB-normalised Ce/Yb of 3.9-10.6 and Sr/Y of 5.8-9.6, MgO contents of 15.7-17.9 wt%, and high Ba and Sr) provide strong evidence for deep metasomatic alteration. High Cr contents in clinopyroxene (800-3740 ppm), garnet (430-1400 ppm), and accessory rutile (700-2530 ppm), together with extremely low Li contents of 1.0-2.4 ppm in clinopyroxene, may indicate hybridisation of the eclogites with peridotite. Comparison of the chemical compositions (major and trace elements) of (1) unaltered fresh cores of coarse-grained garnets from the low-Mg# eclogites, (2) secondary garnet rims (ubiquitous in the low-Mg# eclogites), (3) proto-cores in the coarse-grained garnet (high-Mg# eclogites), and (4) homogeneous recrystallised fine-grained garnets (high-Mg# eclogites) suggests that the high-Mg# eclogites formed through recrystallisation of low-Mg# eclogite in the presence of an external fluid in the mantle. Four of the five high-Mg# samples show that mantle metasomatism inside the Kasai craton mantle beneath the Catoca pipe occurred at a depth range of 145-160 km (4.5-4.8 GPa).
DS1987-0253
1987
Goncharov, A.F.Goncharov, A.F.high pressure stability of diamond ( a review).(Russian)Usp Fiz Nauka (russian), Vol. 152, No. 2, June pp. 317-332RussiaCrystallography
DS201212-0727
2012
Goncharov, A.F.Thomas, S-M., Bina, C.R., Jacobsen, S.D., Goncharov, A.F.Radiative heat transfer in a hydrous mantle transition zone.Earth and Planetary Science Letters, Vol. 357-358, pp. 130-138.MantleGothermometry
DS201506-0283
2015
Goncharov, A.F.Loranov, S.S., Goncharov, A.F., Litasov, K.D.Optical properties of siderite ( FeCo3) across the spin transition: crossover to iron rich carbonates in the lower mantle.American Mineralogist, Vol. 100, pp. 1059-1064.MantleSubduction
DS201603-0379
2015
Goncharov, A.F.Goncharov, A.F., Lobanov, S.S., Tan, X., Hohensee, G.T., Cahill, D.G., Lin, J-F., Thomas, S-M., Okuchi, T., Tomioka, N., Helffrich, G.Experimental study of thermal conductvity at high pressures: implication for the deep Earth's interior.Physics of the Earth and Planetary Interiors, Vol. 247, pp. 11-16.MantleExperimental Petrology

Abstract: Lattice thermal conductivity of ferropericlase and radiative thermal conductivity of iron bearing magnesium silicate perovskite (bridgmanite) - the major mineral of Earth’s lower mantle- have been measured at room temperature up to 30 and 46 GPa, respectively, using time-domain thermoreflectance and optical spectroscopy techniques in diamond anvil cells. The results provide new constraints for the pressure dependencies of the thermal conductivities of Fe bearing minerals. The lattice thermal conductivity of ferropericlase Mg0.9Fe0.1O is 5.7(6) W/(m * K) at ambient conditions, which is almost 10 times smaller than that of pure MgO; however, it increases with pressure much faster (6.1(7)%/GPa vs 3.6(1)%/GPa). The radiative conductivity of a Mg0.94Fe0.06SiO3 bridgmanite single crystal agrees with previously determined values for powder samples at ambient pressure; it is almost pressure-independent in the investigated pressure range. Our results confirm the reduced radiative conductivity scenario for the Earth’s lower mantle, while the assessment of the heat flow through the core-mantle boundary still requires in situ measurements at the relevant pressure-temperature conditions.
DS201803-0462
2017
Goncharov, A.F.Lobanov, S.S., Holtgrewe, N., Lin, J-F, Goncharov, A.F.Radiative conductivity and abundance of post perovskite in the lower most mantle.Earth and Planetary Science Letters, Vol. 479, pp. 43-49.Mantleperovskite

Abstract: Thermal conductivity of the lowermost mantle governs the heat flow out of the core energizing planetary-scale geological processes. Yet, there are no direct experimental measurements of thermal conductivity at relevant pressure-temperature conditions of Earth's core-mantle boundary. Here we determine the radiative conductivity of post-perovskite at near core-mantle boundary conditions by optical absorption measurements in a laser-heated diamond anvil cell. Our results show that the radiative conductivity of Mg0.9Fe0.1SiO3 post-perovskite (?1.1 W/m/K) is almost two times smaller than that of bridgmanite (?2.0 W/m/K) at the base of the mantle. By combining this result with the present-day core-mantle heat flow and available estimations on the lattice thermal conductivity we conclude that post-perovskite is at least as abundant as bridgmanite in the lowermost mantle which has profound implications for the dynamics of the deep Earth.
DS201907-1560
2019
Goncharov, A.F.Martirosyan, N.S., Litasov, K.D., Lobanov, S.S., Goncharov, A.F., Shatskiy, A., Ohfuji, H., Prakapenka, V.The Mg carbonate Fe interaction: implication for the fate of subducted carbonates and formation of diamond in the lower mantle.Geoscience Frontiers, Vol. 10, pp. 1449-1458.Mantlecarbon cycle

Abstract: The fate of subducted carbonates in the lower mantle and at the core-mantle boundary was modelled via experiments in the MgCO3-Fe0 system at 70-150 GPa and 800-2600 K in a laser-heated diamond anvil cell. Using in situ synchrotron X-ray diffraction and ex situ transmission electron microscopy we show that the reduction of Mg-carbonate can be exemplified by: 6MgCO3 + 19Fe = 8FeO +10(Mg0.6Fe0.4)O + Fe7C3 + 3C. The presented results suggest that the interaction of carbonates with Fe0 or Fe0-bearing rocks can produce Fe-carbide and diamond, which can accumulate in the D’’ region, depending on its carbon to Fe ratio. Due to the sluggish kinetics of the transformation, diamond can remain metastable at the core-mantle boundary (CMB) unless it is in a direct contact with Fe-metal. In addition, it can be remobilized by redox melting accompanying the generation of mantle plumes.
DS202002-0204
2019
Goncharov, A.F.Lobanov, S.S., Holtgrewe, N., Ito, G., Badro, J., Piet, H., Babiel, F., Lin, J-F., Bayarjargal, L., Wirth, R., Schrieber, A., Goncharov, A.F.Blocked radiative heat transport in the hot pyrolitic lower mantle.Researchgate.com, 32p. PdfMantlegeothermometry

Abstract: The heat flux across the core-mantle boundary (QCMB) is the key parameter to understand the Earth/s thermal history and evolution. Mineralogical constraints of the QCMB require deciphering contributions of the lattice and radiative components to the thermal conductivity at high pressure and temperature in lower mantle phases with depth-dependent composition. Here we determine the radiative conductivity (krad) of a realistic lower mantle (pyrolite) in situ using an ultra-bright light probe and fast time-resolved spectroscopic techniques in laser-heated diamond anvil cells. We find that the mantle opacity increases critically upon heating to ~3000 K at 40-135 GPa, resulting in an unexpectedly low radiative conductivity decreasing with depth from ~0.8 W/m/K at 1000 km to ~0.35 W/m/K at the CMB, the latter being ~30 times smaller than the estimated lattice thermal conductivity at such conditions. Thus, radiative heat transport is blocked due to an increased optical absorption in the hot lower mantle resulting in a moderate CMB heat flow of ~8.5 TW, at odds with present estimates based on the mantle and core dynamics. This moderate rate of core cooling implies an inner core age of about 1 Gy and is compatible with both thermally- and compositionally-driven ancient geodynamo.
DS202005-0733
2020
Goncharov, A.F.Geballe, Z.M., Sime, N., Badro, J., van Keken, P.E., Goncharov, A.F.Thermal conductivity near the bottom of the Earth's lower mantle: measurements of pyrolite up to 120 Gpa and 2500 K.Earth and Planetary Science Letters, Vol. 536, 116161, 11p. PdfMantlegeothermometry

Abstract: Knowledge of thermal conductivity of mantle minerals is crucial for understanding heat transport from the Earth's core to mantle. At the pressure-temperature conditions of the Earth's core-mantle boundary, calculations of lattice thermal conductivity based on atomistic models have determined values ranging from 1 to 14 W/m/K for bridgmanite and bridgmanite-rich mineral assemblages. Previous studies have been performed at room temperature up to the pressures of the core-mantle boundary, but correcting these to geotherm temperatures may introduce large errors. Here we present the first measurements of lattice thermal conductivity of mantle minerals up to pressures and temperatures near the base of the mantle, 120 GPa and 2500 K. We use a combination of continuous and pulsed laser heating in a diamond anvil cell to measure the lattice thermal conductivity of pyrolite, the assemblage of minerals expected to make up the lower mantle. We find a value of W/m/K at 80 GPa and 2000 to 2500 K and 5.9 W/m/K at 124 GPa and 2000 to 3000 K. These values rule out the highest calculations of thermal conductivity of the Earth's mid-lower mantle (i.e. W/m/K at 80 GPa), and are consistent with both the high and low calculations of thermal conductivity near the base of the lower mantle.
DS202202-0208
2022
Goncharov, A.F.Murakami, M., Goncharov, A.F., Miyajima, N., Yamazaki, D., Holtgrewe, N.Radiative thermal conductivity of single-crystal bridgmanite at the core-mantle boundary with implications for thermal evolution of the Earth.Earth and planetary Science Letters, Vol. 578, 117328, 9p. PdfMantlebridgmanite

Abstract: The Earth has been releasing vast amounts of heat from deep Earth's interior to the surface since its formation, which primarily drives mantle convection and a number of tectonic activities. In this heat transport process the core-mantle boundary where hot molten core is in direct contact with solid-state mantle minerals has played an essential role to transfer thermal energies of the core to the overlying mantle. Although the dominant heat transfer mechanisms at the lowermost mantle is believed to be both conduction and radiation of the primary lowermost mantle mineral, bridgmanite, the radiative thermal conductivity of bridgmanite has so far been poorly constrained. Here we revealed the radiative thermal conductivity of bridgmanite at core-mantle boundary is substantially high approaching to ?5.3±1.2 W/mK based on newly established optical absorption measurement of single-crystal bridgmanite performed in-situ under corresponding deep lower mantle conditions. We found the bulk thermal conductivity at core-mantle boundary becomes ?1.5 times higher than the conventionally assumed value, which supports higher heat flow from core, hence more vigorous mantle convection than expected. Results suggest the mantle is much more efficiently cooled, which would ultimately weaken many tectonic activities driven by the mantle convection more rapidly than expected from conventionally believed thermal conduction behavior.
DS1995-0447
1995
Goncharov, A.G.Drummond, B.J., Goncharov, A.G., Collins, C.D.N.Upper crustal heterogeneities in Australian Precambrian provinces interpreted from deep seismic profiles (Kola)Agso Journal Of Australia Geol.and Geophysics, Vol. 15, No. 4, ppAustraliaGeophysics -seismics, Kola Superdeep Bore Hole
DS1996-0541
1996
Goncharov, A.G.Goncharov, A.G.Anomalous structure of the Mount Isa In lier crust and crust mantle transition zone in global contextGeological Society of Australia 13th. held Feb, No. 41, abstracts p. 159AustraliaStructure, Mount Isa inlier
DS1996-0542
1996
Goncharov, A.G.Goncharov, A.G.Lower crust and crust-mantle transition zone in the eastern part of the Baltic shield, from the reflectionInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 1, p. 104.Russia, Baltic shieldGeophysics -seismics
DS200912-0253
2009
Goncharov, A.G.Glebovitsky, V.A., Nikitina, L.P., Vrevskii, A.B., Pushkarev, M.S., Babushkina, M.S.,Goncharov, A.G.Nature of chemical heterogeneity of the continental lithospheric mantle.Geochemistry International, Vol. 47, 9., Sept. pp. 857-881.MantleGeochemistry
DS200912-0256
2008
Goncharov, A.G.Goncharov, A.G., Saltykova, A.K.Iron valency in minerals of xenoliths and redox state of the upper mantle by Mossbauer spectroscopy data.Hyperfine Interactions, Vol. 186, 1-3, pp. 187-192.MantleMineralogy
DS201012-0238
2010
Goncharov, A.G.Glebovitskii, R.V.A., Nikitina, L.P., Pushkarev, Y.D., Vrevskii, A.B., Goncharov, A.G., Bogomolov, E.S.Sm and Nd geochemistry of mantle xenoliths: the problem of mantle material classification.Doklady Earth Sciences, Vol. 433, 1, pp. 890-893.MantleMantle magmatism
DS201112-0380
2011
Goncharov, A.G.Goncharov, A.G., Ionov, D.A., Doucet, L.S., Ashchepkov, I.V.Redox state of lithospheric mantle in central Siberian craton: a Mossbauer study of peridotite xenoliths from the Udachnaya kimberlite.Goldschmidt Conference 2011, abstract p.930.RussiaGeochronology
DS201212-0254
2012
Goncharov, A.G.Goncharov, A.G., Ionov, D.A.Redox state of deep off-craton lithospheric mantle: new dat a from garnet and spinel peridotites from Vitim, southern Siberia.Contributions to Mineralogy and Petrology, in press available 18p.Russia, SiberiaMetasomatism
DS201212-0255
2012
Goncharov, A.G.Goncharov, A.G., Ionov, D.A.Redox state of deep off-craton lithospheric mantle: new dat a from garnet and spinel peridotites from Vitim, southern Siberia.Contributions to Mineralogy and Petrology, Vol 164, pp. 731-745.RussiaXenoliths - redox
DS201212-0256
2012
Goncharov, A.G.Goncharov, A.G., Ionov, D.A.Redox state of deep off-craton lithospheric mantle: new dat a from garnet and spinel peridotites from Vitim, southern Siberia.Mineralogy and Petrology, Vol. 164, 5, pp. 731-745.RussiaRedox
DS201212-0257
2012
Goncharov, A.G.Goncharov, A.G., Ionov, D.A., Doucet, L.S., Pokhilenko, L.N.Thermal stress, oxygen fugacity and C O H fluid appreciation in cratonic lithospheric mantle: new dat a on peridotite xenoliths from the Udachnaya kimberlite, Siberia.Earth and Planetary Science Letters, Vol. 357-358, pp. 99-110.RussiaDeposit - Udachnaya
DS201412-0208
2014
Goncharov, A.G.Doucet, L.S., Peslier, A.H., Ionov, D.A., Brandon, A.D., Golovin, A.V., Goncharov, A.G., Ashchepkov, I.V.High water contents in the Siberian cratonic mantle linked to metasomatism: an FTIR study of Udachnaya peridotite xenoliths.Geochimica et Cosmochimica Acta, in press availableRussia, SiberiaDeposit - Udachnaya
DS201806-1210
2018
Goncharov, A.G.Babushkina, M.S., Ugolkov, V.L., Marin, Yu.B., Nikitina, L.P., Goncharov, A.G.Hydrogen and carbon groups in the structures of rock forming minerals of rocks of the lithospheric mantle: FTIR and STA + QMS data. Lherzolites, peridotitesDoklady Earth Sciences, Vol. 479, 2, pp. 456-459.Russia, Siberiadeposit - Udachnaya

Abstract: Using IR-Fourier spectrometry (FTIR) and simultaneous thermal analysis combined with quadrupole mass spectrometry of thermal decomposition products (STA + QMS), olivines and clinopyroxene from xenolites of spinel and garnet lherzolites contained in kimberlites and alkaline basalts were studied to confirm the occurrence of hydrogen and carbon within the structure of the minerals, as well as to specify the forms of H and C. The presence of hydroxyl ions (OH-) and molecules of crystal hydrate water (H2Ocryst) along with CO2, CH, CH2, and CH3 groups was detected, which remained within the structures of mantle minerals up to 1300°C (by the data of both techniques). The total water (OH-and H2Ocryst) was the prevailing component of the C-O-H system.
DS202006-0942
2020
Goncharov, A.G.Nikitina, L.P., Goncharov, A.G., Bogomolov, E.S., Beliatsky, B.V., Krimsky, R.Sh., Prichodko, V.S., Babushkina, M.S., Karaman, A.A.HFSE and REE geochemistry and Nd-Sr-Os systematics of peridotites in the subcontinental lithospheric mantle of the Siberian craton and central Asian fold belt junction area: data on mantle xenoliths.Petrology, Vol. 28, 2, pp. 207-219.RussiaREE

Abstract: Mantle xenoliths were found in alkaline basalts of Tokinsky Stanovik (TSt) in the Dzhugdzhur-Stanovoy superterrane (DS) and Vitim plateau (VP) in the Barguzin-Vitim superterrane (BV) (Stanovoy suture area) at junction of the Central Asian Orogenic Belt (CAOB) and the Siberian craton (SC). Xenoliths from TSt basalts are represented by spinel lherzolites, harzburgites, wehrlites; while VP basalts frequently contain spinel-garnet and garnet peridotites lherzolites, and pyroxenites. Xenoliths in kimberlites of the Siberian craton are mainly represented by garnet-bearing lherzolites with abundant eclogite xenoliths (age of 2.7-3.1 Ga), which were not found in mantle of superterranes. The Re-Os determinations point to the Early Archean age of peridotites and eclogites from mantle beneath the Siberian craton. The major and trace (rare-earth and high-filed strength) elements and Nd-Sr-Os composition were analyzed in the peridotites (predominant rocks) of lithospheric mantle at junction of the Central Asian Orogenic Belt and Siberian Craton. The degree of rock depletion in CaO and Al2O3 and enrichment in MgO relative to the primitive mantle in the peridotites of the Dzhugdzhur-Stanovoy superterrane is close to that of the Siberian craton. The peridotites of the Barguzin-Vitim superterrane are characterized by much lower degree of depletion and have mainly a primitive composition. Mantle melting degree reaches up to 45-50% in the Siberian Craton and Dzhugdzhur-Stanovoy superterrane, and is less than 25% in the Barguzin-Vitim terrane. The mantle peridotites of the craton as compared to those of adjacent superterranes are enriched in Ba, Rb, Th, Nb, and Ta and depleted in Y and REE from Sm to Lu. However, all studied peridotites are characterized by mainly superchondritic values of Nb/Ta (>17.4), Zr/Hf (>36.1), Nb/Y (>0.158), and Zr/Y (>2.474). The Nb/Y ratio is predominantly >1.0 in SC peridotites and < 1.0 in the superterrane peridotites. The Nd and Sr isotopic compositions in the latter correspond to those of oceanic basalts. The 187Os/188Os ratio is low (0.108-0.115) in the peridotites of the Siberian Craton and > 0.115 but usually lower than 0.1296 (primitive upper mantle value) in the peridotites of the Dzhugdzhur-Stanovoy and Barguzin-Vitim superterranes. Thus, the geochemical and isotopic composition of peridotites indicates different compositions and types of mantle beneath the Siberian craton and adjacent superterranes of the Central Asian Orogenic Belt in the Early Archean, prior to the formation of 2.7-3.1 Ga eclogites in the cratonic mantle.
DS201012-0540
2010
Goncharov, A.K.Nikitina, L.P., Goncharov, A.K., Babushkina, M.S.The redox state of the continental mantle of the Baikal Mongolia region.Geochemistry International, Vol. 48, 1, pp. 15-40.Russia, AsiaRedox
DS2001-1289
2001
Goncharov, G.N.Zaitseva, T.S., Goncharov, G.N., Gittsovich, SemenovCrystal chemistry of chromium spinel from Imandra Layered pluton, Kola PeninsulaGeochemistry International, Vol. 39, No. 5, pp. 479-81.Russia, Kola PeninsulaSpinels
DS200612-0473
2006
Goncharov, M.A.Goncharov, M.A.Quantitative correlation between geodynamic systems and geodynamic cycles of various ranks.Geotectonics, Vol. 40, 2, Mar. pp. 83-100.MantleGeodynamics - geospheres, convection
DS200612-0692
2006
Goncharov, M.A.Khain, V.E., Goncharov, M.A.Geodynamic cycles and geodynamic systems of various ranks: their relationships and evolution of Earth's history.Geotectonics, Vol. 40, 5, pp. 327-344.MantleGeodynamics
DS201112-0636
2011
Goncharov, M.M.Malitch, K.N., Karpisky, A.P., Sorokhtina, N.V., Goncharov, M.M.Carbonatite of the Guli massif as a possible source of gold: evidence from zirconolite inclusions in Au rich nuggets.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.147-150.Russia, SiberiaGuli
DS201112-0637
2011
Goncharov, M.M.Malitch, K.N., Karpisky, A.P., Sorokhtina, N.V., Goncharov, M.M.Carbonatite of the Guli massif as a possible source of gold: evidence from zirconolite inclusions in Au rich nuggets.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.147-150.Russia, SiberiaGuli
DS201112-0638
2011
Goncharov, M.M.Malitch, K.N., Sorokhtina, N.V., Goncharov, N.N., Goncharov, M.M.Carbonatite of the Guli Massif as a possible source of gold: evidence from zirconolite inclusions in au-rich nuggets.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterRussia, SiberiaCarbonatite
DS201112-0638
2011
Goncharov, N.N.Malitch, K.N., Sorokhtina, N.V., Goncharov, N.N., Goncharov, M.M.Carbonatite of the Guli Massif as a possible source of gold: evidence from zirconolite inclusions in au-rich nuggets.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterRussia, SiberiaCarbonatite
DS1994-0636
1994
Gondi M'Boula, P.C.Gondi M'Boula, P.C.Study of heavy minerals in the alluvium of the Makongonio diamond area.Gabon. (in French)Thesis, Ecole Nat. Superieure de Geol. Nancy France, GlobalKimberlite, lamproite exploration, Heavy mineral sampling
DS200612-0474
2006
Gondwana ResearchGondwana ResearchSpecial issue on crustal structure and tectonic evolution of the southern granulite terrain, India.Gondwana Research, Vol. 10, 1-2, August pp. 1-206.IndiaTectonics, geophysics, magnetics, gravity -not specific
DS1998-1636
1998
Gong, B.Zheng, Y.F., Gong, B., Fu, B., Li, Y.Extreme 13 C depletion in ultrahigh pressure eclogites from the Dabie and Sulu terranes in China.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1698-9.ChinaEclogites, metamorphism, Deposit - Dabie Shan
DS1999-0834
1999
Gong, B.Zheng, Y.F., Fu, B., Gong, B.Hydrogen and oxygen isotope evidence for fluid rock interactions in the stages of pre-post ultra high pressure (UHP) metamorphismLithos, Vol. 48, No. 4, Apr. pp. 677-94.ChinaGeochronology - metamorphic rocks, Dabie Mountains
DS2003-1558
2003
Gong, B.Zheng, Y.F., Gong, B., Zhao, Z.F., Fe, B., Li, Y.L.Two types of gneisses associated with eclogite at Shuanghe in the Dabie terrane:Lithos, Vol. 70, 3-4, pp. 321-343.ChinaUHP, eclogites
DS2003-1559
2003
Gong, B.Zheng, Y-F., Fu, B., Gong, B., Li, L.Stable isotope geochemistry of ultrahigh pressure metamorphic rocks from the DabieEarth Science Reviews, Vol. 62, 1-2, July, pp. 105-161.ChinaUHP, Subduction
DS2003-1560
2003
Gong, B.Zheng, Y-F., Yang, J-J., Gong, B., Jahn, B-M.Partial equilibrium of radiogenic and stable isotope systems in garnet peridotite duringAmerican Mineralogist, Vol. 88, pp. 1633-43.ChinaGeochronology, UHP
DS200412-2155
2004
Gong, B.Xie, Z., Zheng, Y-F., Jahn, B-M., Ballevre, M., Chen, J., Gautier, P., Gao, T., Gong, B., Zhou, J.Sm Nd and Rb Sr dating of pyroxene garnetite from North Dabie in east centra China: problem of isotope disequilibrium due to retChemical Geology, Vol. 206, 1-2, May 28, pp. 137-158.ChinaUHP, eclogite, geochronology
DS200412-2225
2003
Gong, B.Zheng, Y.F., Gong, B., Zhao, Z.F., Fe, B., Li, Y.L.Two types of gneisses associated with eclogite at Shuanghe in the Dabie terrane: carbon isotope, zircon Y.F. dating and oxygen iLithos, Vol. 70, 3-4, pp. 321-343.ChinaUHP, eclogites
DS200412-2226
2003
Gong, B.Zheng, Y-F., Fu, B., Gong, B., Li, L.Stable isotope geochemistry of ultrahigh pressure metamorphic rocks from the Dabie Sulu orogen in China: implications for geodynEarth Science Reviews, Vol. 62, 1-2, July, pp. 105-161.ChinaUHP Subduction
DS200412-2227
2003
Gong, B.Zheng, Y-F., Yang, J-J., Gong, B., Jahn, B-M.Partial equilibrium of radiogenic and stable isotope systems in garnet peridotite during ultrahigh pressure metamorphism.American Mineralogist, Vol. 88, pp. 1633-43.ChinaGeochronology, UHP, Shimafang, Sulu
DS200512-0632
2004
Gong, B.Li, X.P., Zheng, Y.F., Wu, Y.B., Chen, F., Gong, B., Li, Y.L.Low T eclogite in the Dabie terrane of China: petrological and isotopic constraints on fluid activity and radiometric dating.Contributions to Mineralogy and Petrology, Vol. 148, 4, pp. 443-470.ChinaGeochronology
DS200612-1609
2006
Gong, B.Zheng, Y.F., Zhao, Z-F., Wu, Y-B., Gong, B.Protolith nature of deeply subducted continent: zircon U-Pb age, Hf and O isotope constraints from UHP eclogite and gneiss in the Dabie orogen.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 18, abstract only.ChinaUHP, geochronology
DS200712-0369
2007
Gong, B.Gong, B., Zheng, Y-F., Chen, R-X.TC/EA-MS online determination of hydrogen isotope composition and water concentration in eclogitic garnet.Physics and Chemistry of Minerals, Vol. 34, 10, pp. 687-698.TechnologyEclogite
DS200712-0370
2007
Gong, B.Gong, B., Zheng, Y-F., Chen, R-X.H-O isotopes and water content in nominally anhydrous minerals from UHP eclogite in the Dabie Orogen.Plates, Plumes, and Paradigms, 1p. abstract p. A342.ChinaUHP
DS200712-1243
2007
Gong, B.Zheng, Y-F., Wu, Y-B., Zhao, Z-F., Gong, B.Two episodes of zircon growth due to fluid availablility during subduction and exhumation of continental crust: U Pb age, Hf and O isotope evidence from ultrahigh pressure eclogiteFrontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 259-260.ChinaDabie Orogen
DS200712-1244
2007
Gong, B.Zheng, Y-F., Wu, Y-B., Zhao, Z-F., Gong, B.Two episodes of zircon growth due to fluid availablility during subduction and exhumation of continental crust: U Pb age, Hf and O isotope evidence from ultrahigh pressure eclogiteFrontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 259-260.ChinaDabie Orogen
DS200812-0211
2008
Gong, B.Chen, R.X., Zheng, Y.F., Gong, B.Mineral water concentration and H isotope evidence for decompressional dehydration during exhumation of deeply subducted continental crust.Goldschmidt Conference 2008, Abstract p.A156.ChinaUHP
DS200812-1324
2008
Gong, B.Zheng, Y.F., Gong, B., Zhao, Z.F., Wu, Y.B., Chen, P.K.Zircon U Pb age and O isotope evidence for Neoproterozoic low 180 magmatism during super continental rifting in South China: implications for theAmerican Journal of Science, Vol. 308, 4, pp. 484-516.ChinaSnowball Earth
DS201112-1123
2011
Gong, H.Wu, Y., Gao, S., Liu, X., Wang, J., Peng, M., Gong, H., Yuan, H.Two stage exhumation of the ultrahigh pressure metamorphic rocks from the Western Dabie Orogen, central China.Journal of Geology, Vol. 119, pp. 15-32.ChinaUHP
DS201112-1124
2011
Gong, H.Wu, Y., Gao, S., liu, X., Wang, J., peng, M., Gong, H., Yuan, H.Two stage exhumation of ultrahigh pressure metamorphic rocks from the western Dabie orogen, Central China.Journal of Geology, Vol. 119, 1, Jan. pp. 15-31.ChinaUHP
DS201112-1125
2011
Gong, H.Wu, Y., Gao, S., Liu, X., Wang, J., Peng, M., Gong, H., Yuan, H.Two stage exhumation of ultrahigh pressure metamorphic rocks from the western Dabie Orogen, central China.Journal of Petrology, Vol. 119, no. 1, pp. 15-31.ChinaUHP
DS201112-1099
2011
Gong, H-J.Wang, H., Wu, Y-B., Gao, S., Liu, X-C., Gong, H-J., Li, Q-L., Li, X-H., Yuan, H-L.Eclogite origin and timing in the North Qinling terrane, and their bearing on the amalgamation of the South and North Chin a blocks.Journal of Metamorphic Geology, in press available,ChinaCraton
DS201412-0960
2014
Gong, H-J.Wang, H., Wu, Y-B., Gao, S., Zheng, J-P., Liu, Q., Liu, X-C., Qin, Z-W., Yang, S-H., Gong, H-J.Deep subduction of continental crust in accretionary orogen: evidence from U-Pb dating on diamond-bearing zircons from the Qinling orogen, central China.Lithos, Vol. 190-191, pp. 420-429.ChinaUHP
DS201812-2841
2018
Gong, J.Liang, J., Gong, J., Li, W.Applications and impacts of google Earth: a decadal review ( 2006-2016).ISPRS Journal of Photogrammetry and Remote Sensing, Vol. 146, pp. 91-107.Mantleremote sensing

Abstract: Since Google Earth was first released in 2005, it has attracted hundreds of millions of users worldwide and made a profound impact on both academia and industry. It can be said that Google Earth epitomized the first-generation of Digital Earth prototypes. The functionalities and merits that have sustained Google Earth’s lasting influence are worth a retrospective review. In this paper, we take the liberty to conduct a bibliometric study of the applications of Google Earth during 2006-2016. We aim first to quantify the multifaceted impacts, and then to develop a structured understanding of the influence and contribution associated with Google Earth. To accomplish these objectives, we analyzed a total of 2115 Scopus publication records using scientometric methods and then proceed to discussion with a selected set of applications. The findings and conclusions can be summarized as follows: (1) the impact of Google Earth has been profound and persistent over the past decade. Google Earth was mentioned in an average of 229 publications per year since 2009. (2) Broadly, the impact of Google Earth has touched upon most scientific disciplines. Specifically, during 2006-2016, Google Earth has been mentioned in 2115 publications covering all of Scopus’s 26 subject areas; (3) the influence of Google Earth has largely concentrated in GIScience, remote sensing and geosciences. The extended influence of Google Earth has reached a wider range of audiences with a concentration in fields such as human geography, geoscience education and archaeology.
DS201112-0591
2011
Gong, M.Li, H., Li, S., Song, D., Gong, M., Li, X., Jia, J.Crustal and uppermost mantle velocity structure beneath northwestern Chin a from seismic ambient noise tomography.Geophysical Journal International, in press availableChinaGeophysics - seismics
DS1993-0558
1993
Gong, W.Gong, W., Griffin, W.L., O'Reilly, S.Y.Polyphase metamorphic evolution of the Xuanhuaduian eclogite blocks, Dabie Shan high pressure metamorphic belt, central ChinaGeological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A265 abstract onlyChinaEclogite, Dabie
DS201312-0810
2013
Gong, X.H.Shi, R.D., Griffin, W.L., O'Reilly, S.Y., Zhang, X.R., Huang, Q.S., Gong, X.H., Ding, L.Geodynamic constraints on the recycling of ancient SCLM and genesis of Tibetan Diamondiferous ophiolites.Goldschmidt 2013, 1p. AbstractAsia, TibetOphiolites
DS201312-0811
2013
Gong, X.H.Shi, R.D., Griffin, W.L., O'Reilly, S.Y., Zhang, X.R., Huang, Q.S., Gong, X.H., Ding, L.Recycling of ancient SCLM and genesis of Tibetan Diamondiferous ophiolites.Goldschmidt 2013, AbstractAsia, TibetOphiolites
DS201606-1090
2016
Gong, X-H.Griffin, W.L., Afonso, J.C., Belousova, E.A., Gain, S.E., Gong, X-H., Gonzalez-Jiminez, J.M., Howell, D., Huang, J-X., McGowan, N., Pearson, N.J., Satsukawa, T., Shi R., Williams, P., Xiong, Q., Yang, J-S., Zhang, M., O'Reilly, S.Y.Mantle recycling: transition zone metamorphism of Tibetan ophiolitic peridotites and its tectonic implications.Journal of Petrology, in press available, 30p.Asia, China, TibetPeridotite

Abstract: Large peridotite massifs are scattered along the 1500?km length of the Yarlung-Zangbo Suture Zone (southern Tibet, China), the major suture between Asia and Greater India. Diamonds occur in the peridotites and chromitites of several massifs, together with an extensive suite of trace phases that indicate extremely low fO2 (SiC, nitrides, carbides, native elements) and/or ultrahigh pressures (UHP) (diamond, TiO2 II, coesite, possible stishovite). New physical and isotopic (C, N) studies of the diamonds indicate that they are natural, crystallized in a disequilibrium, high-T environment, and spent only a short time at mantle temperatures before exhumation and cooling. These constraints are difficult to reconcile with previous models for the history of the diamond-bearing rocks. Possible evidence for metamorphism in or near the upper part of the Transition Zone includes the following: (1) chromite (in disseminated, nodular and massive chromitites) containing exsolved pyroxenes and coesite, suggesting inversion from a high-P polymorph of chromite; (2) microstructural studies suggesting that the chromitites recrystallized from fine-grained, highly deformed mixtures of wadsleyite and an octahedral polymorph of chromite; (3) a new cubic Mg-silicate, with the space group of ringwoodite but an inverse-spinel structure (all Si in octahedral coordination); (4) harzburgites with coarsely vermicular symplectites of opx + Cr-Al spinel ± cpx; reconstructions suggest that these are the breakdown products of majoritic garnets, with estimated minimum pressures to?>?13?GPa. Evidence for a shallow pre-metamorphic origin for the chromitites and peridotites includes the following: (1) trace-element data showing that the chromitites are typical of suprasubduction-zone (SSZ) chromitites formed by magma mixing or mingling, consistent with Hf-isotope data from magmatic (375?Ma) zircons in the chromitites; (2) the composition of the new cubic Mg-silicate, which suggests a low-P origin as antigorite, subsequently dehydrated; (3) the peridotites themselves, which carry the trace element signature of metasomatism in an SSZ environment, a signature that must have been imposed before the incorporation of the UHP and low-fO2 phases. A proposed P-T-t path involves the original formation of chromitites in mantle-wedge harzburgites, subduction of these harzburgites at c. 375?Ma, residence in the upper Transition Zone for >200 Myr, and rapid exhumation at c. 170-150?Ma or 130-120?Ma. Os-isotope data suggest that the subducted mantle consisted of previously depleted subcontinental lithosphere, dragged down by a subducting oceanic slab. Thermomechanical modeling shows that roll-back of a (much later) subducting slab would produce a high-velocity channelized upwelling that could exhume the buoyant harzburgites (and their chromitites) from the Transition Zone in?
DS200412-0690
2004
Gong, Z.Gong, Z., Fei, Y., Dai, F., Zhang, L., Jing, F.Equation of state and phase stability of mantle perovskite up to 140 GPa shock pressure and its geophysical implications.Geophysical Research Letters, Vol. 31, 4, Feb. 28, DOI 1029/2004 GLO19132MantleGeophysics - UHP
DS201809-2028
2018
Gong, Z.Gong, Z., Xu, X., Evans, D.A.D., Hoffman, P.F., Mitchell, R.N., Bleeker, W.Paleomagnetism and rock magnetism of the ca. 1.87 Ga Pearson Formation, Northwest Territories, Canada: a test of vertical axis rotation within the Great Slave Basin.Precambrian Research , Vol. 305C, pp. 295-309.Canada, Northwest Territoriesgeophysics

Abstract: A geometrically quantitative plate-kinematic model, based on paleomagnetism, for the initial assembly of Laurentia has taken form in the past few decades. Within this framework, there remains but one problematic interval of data predominantly from the Slave craton, which is the 1.96-1.87?Ga Coronation apparent polar wander path (APWP). The Coronation APWP shows large (?110°) back-and-forth oscillations that are difficult to explain in terms of plate motion. Nonetheless, poles from the Coronation APWP have been incorporated in various paleogeographic reconstructions of Laurentia and the supercontinent Nuna, pointing to the importance of testing its veracity. In this study, we conducted a detailed paleomagnetic and rock magnetic study of the ca. 1.87?Ga Pearson Formation, East Arm of Great Slave Lake, Northwest Territories, Canada. Our results show that Pearson Formation yields a characteristic remanent magnetization carried by single-domain or small pseudo-single-domain magnetite. The age of the magnetization is constrained to be older than Paleoproterozoic deformation and is interpreted as primary. Paleomagnetic declinations reveal a one-to-one correlation with local structural attitudes, indicating that some small blocks in the fold belt likely experienced significant (?60°) vertical-axis rotations, presumably related to large dextral displacements along the McDonald Fault system. Alternative explanations, such as true polar wander or a non-dipole magnetic field, are considered less parsimonious for the data presented here. It is suspected that some existing Christie Bay Group poles (the Stark and Tochatwi Formations), which were sampled in areas with anomalous structural attitudes and differ from time-equivalent poles obtained from areas of the Slave craton far from major transcurrent faults, may similarly suffer from vertical-axis rotation. We suggest further study before using possibly rotated Christie Bay Group poles for paleogeographic reconstructions.
DS201811-2605
2018
Gong, Z.Salminen, J., Hanson, R., Evans, D.A.D., Gong, Z., Larson, T., Walker, O., Gumsley, A., Soderlund, U., Ernst, T.Direct Mesoproterozoic connection of the Congo and Kalahari cratons in proto-Africa: strange attractors across supercontinental cycles.Geology, doi.org/10.1130/G45294.1 4p.Africacraton

Abstract: Mobilistic plate-tectonic interpretation of Precambrian orogens requires that two conjoined crustal blocks may derive from distant portions of the globe. Nonetheless, many proposed Precambrian cratonic juxtapositions are broadly similar to those of younger times (so-called “strange attractors”), raising the specter of bias in their construction. We evaluated the possibility that the Congo and Kalahari cratons (Africa) were joined together prior to their amalgamation along the Damara-Lufilian-Zambezi orogen in Cambrian time by studying diabase dikes of the Huila-Epembe swarm and sills in the southern part of the Congo craton in Angola and in Namibia. We present geologic, U-Pb geochronologic, and paleomagnetic evidence showing that these two cratons were directly juxtaposed at ca. 1.1 Ga, but in a slightly modified relative orientation compared to today. Recurring persistence in cratonic connections, with slight variations from one supercontinent to the next, may signify a style of supercontinental transition similar to the northward motion of Gondwana fragments across the Tethys-Indian oceanic tract, reuniting in Eurasia.
DS201902-0316
2019
Gong, Z.Salminen, J., Hanson, R., Evans, D.A.D., Gong, Z., Larson, T., Walker, O., Gumsley, A., Soderlund, U., Ernst, R.Direct Mesoproterozoic connection of the Congo and Kalahari cratons in proto-Africa: strange attractors across supercontinental cycles.Geology, Vol. 46, pp. 1101-1104.Africa, Angola, Namibiacraton

Abstract: Mobilistic plate-tectonic interpretation of Precambrian orogens requires that two conjoined crustal blocks may derive from distant portions of the globe. Nonetheless, many proposed Precambrian cratonic juxtapositions are broadly similar to those of younger times (so-called “strange attractors”), raising the specter of bias in their construction. We evaluated the possibility that the Congo and Kalahari cratons (Africa) were joined together prior to their amalgamation along the Damara-Lufilian-Zambezi orogen in Cambrian time by studying diabase dikes of the Huila-Epembe swarm and sills in the southern part of the Congo craton in Angola and in Namibia. We present geologic, U-Pb geochronologic, and paleomagnetic evidence showing that these two cratons were directly juxtaposed at ca. 1.1 Ga, but in a slightly modified relative orientation compared to today. Recurring persistence in cratonic connections, with slight variations from one supercontinent to the next, may signify a style of supercontinental transition similar to the northward motion of Gondwana fragments across the Tethys-Indian oceanic tract, reuniting in Eurasia.
DS202111-1768
2021
Gong, Z.Gong, Z., Evans, D.A.D., Youbi, N., Lahna, A.A., Sodelund, U., Malek, M.A., Wen, B., Jing, X., Ding, J., Boumedhdi, M.A., Ernst, R.E.Reorienting the West African craton in Paleoproterozoic-Msoproterozoic supercontinent Nuna.Geology, Vol. 49, 10, pp. 1171-1176. pdfAfrica, west AfricaNuna

Abstract: The location of the West African craton (WAC) has been poorly constrained in the Paleoproterozoic-Mesoproterozoic supercontinent Nuna (also known as Columbia). Previous Nuna reconstruction models suggested that the WAC was connected to Amazonia in a way similar to their relative position in Gondwana. By an integrated paleomagnetic and geochronological study of the Proterozoic mafic dikes in the Anti-Atlas Belt, Morocco, we provide two reliable paleomagnetic poles to test this connection. Incorporating our new poles with quality-filtered poles from the neighboring cratons of the WAC, we propose an inverted WAC-Amazonia connection, with the northern WAC attached to northeastern Amazonia, as well as a refined configuration of Nuna. Global large igneous province records also conform to our new reconstruction. The inverted WAC-Amazonia connection suggests a substantial change in their relative orientation from Nuna to Gondwana, providing an additional example of large-magnitude cumulative azimuthal rotations between adjacent continental blocks over supercontinental cycles.
DS202202-0192
2022
Gong, Z.Gong, Z., Evans, D.A.D.Paleomagnetic survey of the Goulburn Supergroup, Kilohigok Basin, Nunavut Canada: toward an understanding of the Ososirian apparent polar wander path of the Slave craton.Precambrian Research, Vol. 369, 106516, 16p.Canada, Nunavutgeophysics - magnetics

Abstract: The Orosirian paleopoles from the three circum-Slave basins (i.e., the Great Slave, Coronation, and Kilohigok Basins) of the Slave craton show large (?110°) and back-and-forth swings at 1.96-1.87 Ga, known as the Coronation loops. The Coronation loops, taken at face value, would imply rapid and substantial spin motions of the Slave craton, which is at odds with modern plate tectonics. Alternatively, the Coronation loops have been interpreted as a product of basin-scale rotations, local-scale vertical-axis rotations, or inertial interchange true polar wander (IITPW). One way to differentiate these models is to take advantage of the well-correlated stratigraphy in three circum-Slave basins and directly compare the time-equivalent paleomagnetic results. In this study, we collected ?300 samples from nine formations from the Goulburn Supergroup of the Kilohigok Basin, in shallowly dipping autochthonous sections east of the Bathurst Fault. We provide seven new reconnaissance-level paleopoles of the Slave craton, namely from the Kenyon, Hackett, Rifle, Beechey, Link, Kuuvik, and Brown Sound Formations of the Goulburn Supergroup. Our results and the compiled Orosirian paleomagnetic data of the Slave craton suggest that although basin-scale rotation or local vertical-axis rotation in fault zones are able to explain some of the disagreements among time-correlative paleopoles, they could not account for the large declination variation within the homoclinal sections in individual basins. Notably, our results from the ?1963 Ma Rifle Formation show progressive changes in declination through the stratigraphy, which cannot be explained by either basin-scale or local vertical-axis rotations. Selective remagnetization is also considered unlikely to be the cause. Instead, we suggest that IITPW could potentially be responsible for the Coronation loops, which could also provide an explanation for some discrepant paleomagnetic data observed globally during the Orosirian time.
DS200712-1227
2006
Gong, Z.Z.Zhang, L., Gong, Z.Z.Shock compression and phase transitions of magnesiowustite ( MgFe)O up to Earth's lowermost mantle conditions.Chinese Physics Letters, Vol. 23, 11, pp. 3049-3051. Ingenta 1064786273MantleMineralogy
DS1990-1535
1990
Gong GuohongWang Guanxin, Gong GuohongX-ray powder diffraction characterization of pyropeInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 358-359ChinaMineralogy, Pyrope
DS1975-0086
1975
Gong PuGong PuSome Experiences in Prospecting for a Certain Diamond DeposiActa Geol. Sinica., No. 2, PP. 106-110.ChinaProspecting
DS1990-0583
1990
Gong WeiliangGong WeiliangOn high -temperature phase transitions of metamict fergusonite group minerals from Baiyun OboInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 934-936ChinaCarbonatite, Baiyan Obo -fergusonite
DS1987-0790
1987
Gongshi LiWhitten, T.E.H., Bornhorst, T.J., Gongshi Li, Hicks, D.L., BeckwithSuites, subdivision of batholiths and igneous rock classification:geological and mathematical conceptualizationAmerican Journal of Science, Vol. 287, April pp. 332-352GlobalClassification, Igneous rocks
DS1989-0062
1989
Goni, J.Balasubramaniam, K.S., Faure, G., Goni, J., Grubb, P.L.C.Weathering : its products and deposits.Vol. 1. processes. Vol. IIGeotechnicsAugustithis Publishing, (Greece), Vol. I 462p. $ 50.00 Vol. II 672p. $ 65.00GlobalWeathering, Deposits -processes
DS2002-0592
2002
Gonnermann, H.M.Gonnermann, H.M., Manga, M., Jellinek, A.M.Dynamics and longevity of an initially stratified mantleGeophysical Research Letters, Vol. 29,10,May15,pp.33-MantleGeodynamics
DS2003-0652
2003
Gonnermann, H.M.Jellinek, A.M., Gonnermann, H.M., Richards, M.A.Plume capture by divergent plate motions: implications for the distribution of hotspotsEarth and Planetary Science Letters, Vol. 205, 3-4, pp. 361-78.MantleGeothermometry, Core - mantle boundary
DS200412-0691
2004
Gonnermann, H.M.Gonnermann, H.M., Jellinek, A.M., Richards, M.A., Manga, M.Modulation of mantle plumes and heat flow at the core mantle boundary by plate scale flow: results from laboratory experiments.Earth and Planetary Science Letters, Vol. 226, 1-2, pp. 53-67.MantleGeothermometry, boundary
DS201607-1296
2016
Gonnermann, H.M.Gonnermann, H.M.Magma fragmentation.Annual Review of Earth and Planetary Sciences, Vol. 43, pp. 431-458.MantleMagmatism

Abstract: Magma fragmentation is the breakup of a continuous volume of molten rock into discrete pieces, called pyroclasts. Because magma contains bubbles of compressible magmatic volatiles, decompression of low-viscosity magma leads to rapid expansion. The magma is torn into fragments, as it is stretched into hydrodynamically unstable sheets and filaments. If the magma is highly viscous, resistance to bubble growth will instead lead to excess gas pressure and the magma will deform viscoelastically by fracturing like a glassy solid, resulting in the formation of a violently expanding gas-pyroclast mixture. In either case, fragmentation represents the conversion of potential energy into the surface energy of the newly created fragments and the kinetic energy of the expanding gas-pyroclast mixture. If magma comes into contact with external water, the conversion of thermal energy will vaporize water and quench magma at the melt-water interface, thus creating dynamic stresses that cause fragmentation and the release of kinetic energy. Lastly, shear deformation of highly viscous magma may cause brittle fractures and release seismic energy.
DS1996-1415
1996
Gonsaga, G.H.Teixeira, N.A., Gonsaga, G.H., Gaspar, J.C.Diamond geology; the Brazilian Cretaceous as an example. in PortFourth Symposium on the Cretaceous of Brasil, Dep. Geol. Sed., Vol. 4, pp. 247-254.BrazilStratigraphy, Kimberlites
DS201112-0381
2010
Gonsaga, R.G.Gonsaga, R.G.Eclogitos e piroxenitos: seu significado na evolucao e reciciclagem do sistema manto-crosta.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 17.South America, BrazilEclogite and pyroxenites - provenance
DS201212-0113
2012
Gonscalves, A.O.Castillo-Oliver, M., Gali, S., Gonscalves, A.O., Melgarejo, J.C.Use of indicator minerals in diamond exploration: a comparison between barren and fertile kimberlites in Angola.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, AngolaGeochemistry - KIMS
DS1960-1111
1969
Gonshakova, V.I.Gonshakova, V.I., Ruzhitskiy, V.O., Boychuk, M.D., et al.Volcanic Pipes and Dikes of Kimberlite Rocks on the RussianplatformInternational Geology Review, Vol. LL, No. 1, PP. 60-73.RussiaBlank
DS1960-1112
1969
Gonshakova, V.I.Gonshakova, V.I., Ruzhitskiy, V.O., Strekozov, N.F., et al.Alkalic Ultrabasic Rocks Similar to Kimberlites from the Southern Russian PlatformSovetsk. Geol., No. 8, PP. 139-145.RussiaBlank
DS1987-0688
1987
Gontar, A.G.Smirnova, O.I., Godik, E.E., Gontar, A.G.Long lived excited states of boron in diamondSoviet Physics Jetp, Vol. 21, No. 7, July pp. 774-777GlobalBlank
DS2001-0356
2001
Gonzaga, G.Garanin, V.K., Gonzaga, G., Campos, J., Kudryavtseva, G.A new theory of the glacial origin of diamond placers in the Ural regionMoscow University of Geol. Bulletin., Vol. 55, No. 5, pp. 54-8.Russia, UralsAlluvials - placers, Geomorphology
DS1989-1506
1989
Gonzaga, G.M.Tompkins, L.A., Gonzaga, G.M.Diamonds in Brasil and a proposed model for the origin and distribution Of diamonds in the Coromandel region,Minas Gerais, BrasilEconomic Geology, Vol. 84, No. 3, May pp. 591-602BrazilDiamond genesis, Diamond occurrences, distr
DS1991-0339
1991
Gonzaga, G.M.Danni, J.C.M., Gapsar, J.C., Gonzaga, G.M.The Fazenda Alagoinha intrusion, Tres Ranchos, GoaisFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 31-36BrazilGeology, Kimberlitic intrusions
DS1991-0341
1991
Gonzaga, G.M.Dardenne, M.A., Gonzaga, G.M., Campos, J.E.G.The diamond bearing Cretaceous conglomerates of the Canabrava area, MinasGerais, BrasilFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 83-88BrazilConglomerates, Alluvial diamonds
DS1991-0587
1991
Gonzaga, G.M.Gonzaga, G.M., Dardenne, M.A.The Jequitai glaciation and the dispersion of diamondsFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 89-94BrazilGeomorphology, Alluvial diamonds
DS1994-0637
1994
Gonzaga, G.M.Gonzaga, G.M., Teixeira, N.A., Gaspar, J.C.The origin of diamonds in western Minas Gerais, BrasilMineralium Deposita, Vol. 29, 5, Nov. pp. 414-421.BrazilDiamond genesis
DS1995-0651
1995
Gonzaga, G.M.Gonzaga, G.M., Teixeira, N.A., Gaspar, J.C.Geotectonic considerations on primary sources in mobile beltsProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 184-186.South Africa, ZimbabweCraton -mobile belts, Deposit -River Ranch, Venetia
DS1998-0522
1998
Gonzaga, G.M.Gonzaga, G.M., Gaspar, J.C., Araujo, D.P.Helium and Berylium isotopes as a diamond exploration tool: some thoughts based on literature data.7th International Kimberlite Conference Abstract, pp. 256-8.Australia, Botswana, South AfricaCosmogenic, helium, noble gases, geochronology, Deposit - Ellendale, Orapa, Premier
DS2001-0638
2001
Gonzaga, G.M.Kudryavtseva, G.P., Tikhova, M.A., Gonzaga, G.M.Comparative charcteristics of specific morphological features of diamonds from northern and northeastern European Russia ( Urals, Timan, and Arkhangelsk).Moscow University Geology Bulletin, Vol. 56, 6, pp. 26-30.Russia, Urals, TimanDiamond - morphology
DS201412-0303
2014
Gonzaga, G.M.Gonzaga, G.M.A regiao de Canaveiras -BA continua sendo o unico local com diamantes no litoral Brasileiro.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 3p. AbstractSouth America, BrazilDeposit - Canaveriras
DS201412-0304
2014
Gonzaga, G.M.Gonzaga, G.M., Gonzaga, R.G.Important differences between glacial and fluvial systems in relation to diamond geology.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 2p. AbstractSouth America, BrazilGeomorphology
DS201012-0243
2010
Gonzaga, R.G.Gonzaga, R.G., Lowry, D., Jacob, D.E., Le Roex, A., Schulze, D., Menzies, M.A.Eclogites and garnet pyroxenes: similarities and differences.Journal of Volcanology and Geothermal Research, Vol. 190, 1-2 pp. 235-247.TechnologyEclogite
DS201012-0244
2010
Gonzaga, R.G.Gonzaga, R.G., Menzies, M.A., Thirwala, M.F., Jacob, D.E., Le Roex, A.Eclogites and garnet pyroxenites: problems resolving provenance using Lu-Hf, Sm-Nd and Rb-Sr isotope systems.Journal of Petrology, Vol. 51, 1-2, pp. 513-535.MantleGeochronology
DS201412-0304
2014
Gonzaga, R.G.Gonzaga, G.M., Gonzaga, R.G.Important differences between glacial and fluvial systems in relation to diamond geology.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 2p. AbstractSouth America, BrazilGeomorphology
DS1998-0756
1998
GonzalesKirkley, M.B., Kolebaba, M.R., Carlson, J.A., GonzalesKimberlite emplacement processes interpreted from Lac de Gras examples7th International Kimberlite Conference Abstract, pp. 429-431.Northwest TerritoriesKimberlite genesis, structure, tectonics, emplacement, Deposit - Lac de gras area
DS202106-0938
2021
Gonzales, A.Gonzales, A.New rating system for coloured gemstones.Gems&Jewellery, Vol. 30, 1, p. 31.Globalgemstones
DS2000-0237
2000
Gonzales, A.M.Diorio, P.A., Lockhart, G.D., Gonzales, A.M.Airborne gravity gradiometer survey over the Ekati property28th. Yellowknife Geoscience Forum, p. 19-20.abstractNorthwest TerritoriesGeophysics - gravity Airborne, Deposit - Ekati
DS2003-0482
2003
Gonzales, A.M.Gonzales, A.M., Baumgartner, M., Gelo, K.The Ranch Lake indicator mineral train: single or multiple sources?8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractNorthwest TerritoriesDeposit - Ranch Lake
DS200412-0692
2003
Gonzales, A.M.Gonzales, A.M., Baumgartner, M., Gelo, K.The Ranch Lake indicator mineral train: single or multiple sources?8 IKC Program, Session 8, POSTER abstractCanada, Northwest TerritoriesDiamond exploration Deposit - Ranch Lake
DS201609-1719
2016
Gonzales, C.M.Gonzales, C.M., Gorczyk, W., Gerya, T.V.Decarbonation of subducting slabs: insight from petrological-thermomechanical modeling.Gondwana Research, Vol. 36, pp. 314-332.MantleSubduction

Abstract: Subduction of heterogeneous lithologies (sediments and altered basalts) carries a mixture of volatile components (H2O ± CO2) into the mantle, which are later mobilized during episodes of devolatilization and flux melting. Several petrologic and thermodynamic studies investigated CO2 decarbonation to better understand carbon cycling at convergent margins. A paradox arose when investigations showed little to no decarbonation along present day subduction geotherms at subarc depths despite field based observations. Sediment diapirism is invoked as one of several methods for carbon transfer from the subducting slab. We employ high-resolution 2D petrological-thermomechanical modeling to elucidate the role subduction dynamics has with respect to slab decarbonation and the sediment diapirism hypothesis. Our thermodynamic database is modified to account for H2O-CO2 binary fluids via the following lithologies: GLOSS average sediments (H2O: 7.29 wt.% & CO2: 3.01 wt.%), carbonated altered basalts (H2O: 2.63 wt.% & CO2: 2.90 wt.%), and carbonated peridotites (H2O: 1.98 wt.% & CO2: 1.50 wt.%). We include a CO2 solubility P-x[H2O wt.%] parameterization for sediment melts. We parameterize our model by varying two components: slab age (20, 40, 60, 80 Ma) and convergence velocity (1, 2, 3, 4, 5, 6 cm year? 1). 59 numerical models were run and show excellent agreement with the original code base. Three geodynamic regimes showed significant decarbonation. 1) Sedimentary diapirism acts as an efficient physical mechanism for CO2 removal from the slab as it advects into the hotter mantle wedge. 2) If subduction rates are slow, frictional coupling between the subducting and overriding plate occurs. Mafic crust is mechanically incorporated into a section of the lower crust and undergoes decarbonation. 3) During extension and slab rollback, interaction between hot asthenosphere and sediments at shallow depths result in a small window (~ 12.5 Ma) of high integrated CO2 fluxes (205 kg m? 3 Ma? 1).
DS201112-1155
2011
Gonzales, D.A.Zbrozek, M.C., Gonzales, D.A.Insight into the volatile histories of magmas of the Navajo volcanic field using oxygen and carbon isotopes.Geological Society of America, Annual Meeting, Minneapolis, Oct. 9-12, abstractUnited States, New Mexico, Colorado PlateauCarbonatite, Katungites, minettes
DS2000-0348
2000
Gonzales, T.Gonzales, T., Lockhart, G., Carlson, J.A.Exploration and discovery of kimberlites - EKATI diamonds projectGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 2p. abstract.Northwest TerritoriesHistory - exploration - brief, Deposit - Ekati
DS201902-0270
2018
Gonzales-Jimenez, J.M.Farre-de-Pablo, J., Proenza, J.A., Gonzales-Jimenez, J.M., Garcia-Casco, A., Colas, V., Roque-Rossell, J., Camprubi, A., Sanchez-Navas, A.A shallow origin for diamonds in ophiolitic chromitites.Geology, Vol. 46, pp. 75-78.Mexico, Pueblaophiolite

Abstract: Recent findings of diamonds in ophiolitic peridotites and chromitites challenge our traditional notion of Earth mantle dynamics. Models attempting to explain these findings involve incorporation of diamonds into chromite near the mantle transition zone. However, the occurrence of metastable diamonds in this context has not been considered. Here, we report for the first time in situ microdiamonds in chromite from ophiolitic chromitite pods hosted in the Tehuitzingo serpentinite (southern Mexico). Here, diamonds occur as fracture-filling inclusions along with quartz, clinochlore, serpentine, and amorphous carbon, thus indicating a secondary origin during the shallow hydration of chromitite. Chromite chemical variations across the diamond-bearing healed fractures indicate formation during the retrograde evolution of chromitite at temperatures between 670 °C and 515 °C. During this stage, diamond precipitated metastably at low pressure from reduced C-O-H fluids that infiltrated from the host peridotite at the onset of serpentinization processes. Diamond was preserved as a result of fracture healing at the same temperature interval in which the chromite alteration began. These mechanisms of diamond formation challenge the idea that the occurrence of diamond in ophiolitic rocks constitutes an unequivocal indicator of ultrahigh-pressure conditions.
DS202008-1396
2020
Gonzales-Jiminez, J.M.Gonzales-Jiminez, J.M., Tassara, S., Schettino, E., Roque-Rosell, J., Farre-de-Pablo, J., Saunders, J.E., Deditius, A.P., Colas, V., Rovira-Medina, J.J., Guadalupe Davalos, M., Schilling, M., Jiminez-Franco, A., Marchesi, C., Nieto, F., Proenza, J.A., GerMineralogy of the HSE in the subcontinental lithospheric mantle - an interpretive review.Lithos, in press available, 44p. PdfMantleHSE

Abstract: The highly siderophile elements (HSE: Os, Ir, Ru, Rh, Pt, Pd, Re, Au) exist in solid solution in accessory base-metal sulfides (BMS) as well as nano-to-micron scale minerals in rocks of the subcontinental lithospheric mantle (SCLM). The latter include platinum-group minerals (PGM) and gold minerals, which may vary widely in morphology, composition and distribution. The PGM form isolated grains often associated with larger BMS hosted in residual olivine, located at interstices in between peridotite-forming minerals or more commonly in association with metasomatic minerals (pyroxenes, carbonates, phosphates) and silicate glasses in some peridotite xenoliths. The PGM found inside residual olivine are mainly Os-, Ir- and Ru-rich sulfides and alloys. In contrast, those associated with metasomatic minerals or silicate glasses of peridotite xenoliths consist of Pt, Pd, and Rh bonded with semimetals like As, Te, Bi, and Sn. Nanoscale observations on natural samples along with the results of recent experiments indicate that nucleation of PGM is mainly related with the uptake of HSE by nanoparticles, nanominerals or nanomelts at high temperature (> 900?°C) in both silicate and/or sulfide melts, regardless of the residual or metasomatic origin of their host minerals. A similar interpretation can be assumed for gold minerals. Our observations highlight that nanoscale processes play an important role on the ore-forming potential of primitive mantle-derived magmas parental to magmatic-hydrothermal deposits enriched in noble metals. The metal inventory in these magmas could be related with the physical incorporation of HSE-bearing nanoparticles or nanomelts during processes of partial melting of mantle peridotite and melt migration from the mantle to overlying continental crust.
DS202102-0175
2020
Gonzales-Jiminez, J.M.Blanks, D.E., Holwell, D.A., Fiorentini, M.L., Moroni, M., Giuliani, A., Tassara, S., Gonzales-Jiminez, J.M., Boyce, A.J., Ferrari, E.Fluxing of mantle carbon as a physical agent for metallogenic fertilization of the crust.Nature Communications, doi.org/10.1038/ s41467-020-18157-6 11p. Pdf Mantlecarbon

Abstract: Magmatic systems play a crucial role in enriching the crust with volatiles and elements that reside primarily within the Earth’s mantle, including economically important metals like nickel, copper and platinum-group elements. However, transport of these metals within silicate magmas primarily occurs within dense sulfide liquids, which tend to coalesce, settle and not be efficiently transported in ascending magmas. Here we show textural observations, backed up with carbon and oxygen isotope data, which indicate an intimate association between mantle-derived carbonates and sulfides in some mafic-ultramafic magmatic systems emplaced at the base of the continental crust. We propose that carbon, as a buoyant supercritical CO2 fluid, might be a covert agent aiding and promoting the physical transport of sulfides across the mantle-crust transition. This may be a common but cryptic mechanism that facilitates cycling of volatiles and metals from the mantle to the lower-to-mid continental crust, which leaves little footprint behind by the time magmas reach the Earth’s surface.
DS202106-0965
2021
Gonzales-Jiminez, J.M.Pujol-Sola, N., Dominguez-Carretero, D., Proenza, J.A., Haissen, F., Ikenne, M., Gonzales-Jiminez, J.M., Colas, V., Maacha, L., Garcia-Casco, A.The chromitites of the Neoproterozoic Bou Azzer ophiolite ( central Anti-Atlas, Morocco) revisited.Ore Geology Reviews, Vol. 134, 104166, 24p. PdfAfrica, Moroccomoissanite

Abstract: The Neoproterozoic Bou Azzer ophiolite in the Moroccan Anti-Atlas Panafrican belt hosts numerous chromitite orebodies within the peridotite section of the oceanic mantle. The chromitites are strongly affected by serpentinization and metamorphism, although they still preserve igneous relicts amenable for petrogenetic interpretation. The major, minor and trace element composition of unaltered chromite cores reveal two compositional groups: intermediate-Cr (Cr# = 0.60 - 0.74) and high-Cr (Cr# = 0.79 - 0.84) and estimates of parental melt compositions suggest crystallization from pulses of fore-arc basalts (FAB) and boninitic melts, respectively, that infiltrated the oceanic supra-subduction zone (SSZ) mantle. A platinum group elements (PGE) mineralization dominated by Ir-Ru-Os is recognized in the chromitites, which has its mineralogical expression in abundant inclusions of Os-Ir alloys and coexisting magmatic laurite (RuS2) and their products of metamorphic alteration. Unusual mineral phases in chromite, not previously reported in this ophiolite, include super-reduced and/or nominally ultra-high pressure minerals moissanite (SiC), native Cu and silicates (oriented clinopyroxene lamellae), but “exotic” zircon and diaspore have also been identified. We interpret that clinopyroxene lamellae have a magmatic origin, whereas super-reduced phases originated during serpentinization processes and diaspore is linked to late circulation of low-silica fluids related to rodingitization. Zircon grains, on the other hand, with apatite and serpentine inclusions, could either have formed after the interaction of chromitite with mantle-derived melts or could represent subducted detrital sediments later incorporated into the chromitites. We offer a comparison of the Bou Azzer chromitites with other Precambrian ophiolitic chromitites worldwide, which are rather scarce in the geological record. The studied chromitites are very similar to the Neoproterozoic chromitites reported in the Arabian-Nubian shield, which are also related to the Panafrican orogeny. Thus, we conclude that the Bou Azzer chromitites formed in a subduction-initiation geodynamic setting with two-stages of evolution, with formation of FAB-derived intermediate-Cr chromitites in the early stage and formation of boninite-derived high-Cr chromitites in the late stage.
DS201712-2687
2016
Gonzales-Platas, J.Gonzales-Platas, J., Alvaro, M., Nestola, F., Angel, R.J. .EosFIT7-GUI: a new graphical user interface for equation of state calculations, analyses and teaching.Journal of Applied Crystallography, Vol. 49, pp. 1377-1382.Technologyanalyses

Abstract: EosFit7-GUI is a full graphical user interface designed to simplify the analysis of thermal expansion and equations of state (EoSs). The software allows users to easily perform least-squares fitting of EoS parameters to diffraction data collected as a function of varying pressure, temperature or both. It has been especially designed to allow rapid graphical evaluation of both parametric data and the EoS fitted to the data, making it useful both for data analysis and for teaching.
DS201602-0187
2015
Gonzalez, A.Agrusta, R., Tommasi, A., Arcay, D., Gonzalez, A., Gerya, T.How partial melting affects small-scale convection in a plume-fed sublithospheric layer beneath fast-moving plates.Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 11, Nov. pp. 3924-3945.MantleConvection

Abstract: Numerical models show that small-scale convection (SSC) occurring atop a mantle plume is a plausible mechanism to rejuvenate the lithosphere. The triggering of SSC depends on the density contrast and on the rheology of the unstable layer underlying the stagnant upper part of the thermal boundary layer (TBL). Partial melting may change both properties. We analyze, using 2-D numerical simulations, how partial melting influences the dynamics of time-dependent SSC instabilities and the resulting thermo-mechanical rejuvenation of an oceanic plate moving atop of a plume. Our simulations show a complex behavior, with acceleration, no change, or delay of the SSC onset, due to competing effects of the latent heat of partial melting, which cools the plume material, and of the buoyancy increase associated with both melt retention and depletion of residue following melt extraction. The melt-induced viscosity reduction is too localized to affect significantly SSC dynamics. Faster SSC triggering is promoted for low melting degrees (low plume temperature anomalies, thick lithosphere, or fast moving plates), which limit both the temperature reduction due to latent heat of melting and the accumulation of depleted buoyant residue in the upper part of the unstable layer. In contrast, high partial melting degrees lead to a strong temperate decrease due to latent heat of melting and development of a thick depleted layer within the sublithospheric convecting layer, which delay the development of gravitational instabilities. Despite differences in SSC dynamics, the thinning of the lithosphere is not significantly enhanced relatively to simulations that neglect partial melting.
DS201710-2228
2017
Gonzalez, C.M.Gonzalez, C.M., Gorczyk, W.Decarbonation in an intracratonic setting: insight from petrological- thermomechanical modeling.Journal of Geophysical Research: Solid Earth, Vol. 122, 8, pp. 5992-6013.Mantlegeothermometry

Abstract: Cratons form the stable core roots of the continental crust. Despite long-term stability, cratons have failed in the past. Cratonic destruction (e.g., North Atlantic Craton) due to chemical rejuvenation at the base of the lithosphere remains poorly constrained numerically. We use 2-D petrological-thermomechanical models to assess cratonic rifting characteristics and mantle CO2 degassing in the presence of a carbonated subcontinental lithospheric mantle (SCLM). We test two tectonothermal SCLM compositions: Archon (depleted) and Tecton (fertilized) using 2 CO2 wt % in the bulk composition to represent a metasomatized SCLM. We parameterize cratonic breakup via extensional duration (7-12 Ma; full breakup), tectonothermal age, TMoho (300-600°C), and crustal rheology. The two compositions with metasomatized SCLMs share similar rifting features and decarbonation trends during initial extension. However, we show long-term (>67 Ma) stability differences due to lithospheric density contrasts between SCLM compositions. The Tecton model shows convective removal and thinning of the metasomatized SCLM during failed rifting. The Archon composition remained stable, highlighting the primary role for SCLM density even when metasomatized at its base. In the short-term, three failed rifting characteristics emerge: failed rifting without decarbonation, failed rifting with decarbonation, and semifailed rifting with dry asthenospheric melting and decarbonation. Decarbonation trends were greatest in the failed rifts, reaching peak fluxes of 94 × 104 kg m?3. Increased TMoho did not alter the effects of rifting or decarbonation. Lastly, we show mantle regions where decarbonation, mantle melting in the presence of carbonate, and preservation of carbonated mantle occur during rifting.
DS201906-1271
2019
Gonzalez, G.Barry, P.H., de Moor, J.M., Giovannelli, D., Schrenk, M., Hummer, D.R., Lopez, T., Pratt, C.A., Alpizar Segua, Y., Battaglia, A., Beaudry, A., Bini, G., Cascante, M., d'Errico, G., di Carlo, M., Fattorini, D., Fullerton, K., H+Gazel, E., Gonzalez, G., HalForearc carbon sink reduces long term volatile recycling into the mantle.Nature , 588, 7753, p. 487.Mantlecarbon

Abstract: Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth’s surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth’s deep mantle and shallow crustal reservoirs, as well as Earth’s oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth’s deep mantle than previously estimated.
DS202105-0765
2021
Gonzalez-Alvarez, I.Gonzalez-Alvarez, I., Stoppa, F., Yang, X.Y., Porwal, A.Introduction to the special issue, insights on carbonatites and their mineral exploration approach: a challenge towards resourcing critical metals.Ore Geology Reviews, Vol. 133, 104073, 7p. PdfGlobalcarbonatites

Abstract: Population growth and technological progress in the last 50 years have resulted in the global demand for mineral resources increasing by 400% since 1970, and it is further expected to almost double by 2050. This context forecasts a never-seen-before market for some specific mineral commodities, termed critical metals. The resource and supply flow of critical metals would be decisive for the economic well-being of economies in near future. Carbonatites are the most prospective host rocks for Rare Earth Elements (REEs), which constitute some of the most important critical elements. This special issue aims to contribute to the debate on understanding the genesis of carbonatites and their prospectivity for REEs (including exploration strategies), by presenting a wide variety of studies on carbonatites from around the globe.
DS202204-0515
2022
Gonzalez-Alvarez, I.Barrett, N., Jaques, A.L., Gonzalez-Alvarez, I., Walter, M.J., Pearson, G.Ultra-refractory peridotites of Phanerozoic mantle origin: the Papua New Guinea ophiolite mantle tectonites. ( harzburgites and peridotites)Journal of Petrology, 10.1093/petrology/egac014Asia, Papua New Guineaperidotites

Abstract: Harzburgites and dunites forming the base of the Late Cretaceous-Paleocene Papuan Ultramafic Belt (PUB) and Marum ophiolites of Papua New Guinea (PNG) are amongst the most refractory mantle peridotites on Earth. We present a new integrated dataset of major element, bulk plus mineral trace element and Re-Os isotopic analyses aimed at better understanding the genesis of these peridotites. The PUB harzburgites contain olivine (Fo92-93), low-Al enstatite (less than or equal to 0.5 wt. % Al2O3 and CaO), and Cr-rich spinel (Cr# = 0.90-0.95). The Marum harzburgites are less refractory with olivine (Fo91.9-92.7), enstatite (~0.5-1.0 wt. % Al2O3 and CaO), minor clinopyroxene (diopside), and spinel (Cr# = 0.71-0.77). These major element characteristics reflect equivalent or greater levels of melt depletion than that experienced by Archean cratonic peridotites. Whereas bulk-rock heavy rare earth element (HREE) abundances mirror the refractory character indicated by the mineral chemistry and major elements, large-ion lithophile elements (LILEs) indicate a more complex melting and metasomatic history. In-situ olivine and orthopyroxene REE measurements show that harzburgites and dunites have experienced distinct melt-rock interaction processes, with dunite channels/lenses, specifically, showing higher abundances of HREE in olivine. Distinctive severe inter-element fraction of platinum group elements and Re result in complex patterns that we refer to as “M-shaped”. These fractionated highly siderophile element (HSE) patterns likely reflect the dissolution of HSE-rich phases in highly depleted peridotites by interaction with subduction-related melts/fluids, possibly high-temperature boninites. Osmium isotope compositions of the PNG peridotites are variable (187Os/188Os = 0.1204 to 0.1611), but fall within the range of peridotites derived from Phanerozoic oceanic mantle, providing no support for ancient melt depletion, despite their refractory character. This provides further evidence that highly depleted peridotites can be produced in the modern Earth, in subduction zone environments. The complex geochemistry indicates a multi-stage process for the formation of the PNG mantle peridotites in a modern geodynamic environment. The first stage involves partial melting at low-pressure (<2 GPa) and high-temperature (~1250-1350 0C) to form low-K, low-Ti tholeiitic magmas that formed the overlying cumulate peridotite-gabbro and basalt (PUB only) sequences of the ophiolites. This is inferred to have occurred in a fore-arc setting at the initiation of subduction. Later stages involved fluxing of the residual harzburgites with hydrous fluids and melts to form replacive dunites and enstatite dykes, and interaction of the residual peridotites in the overlying mantle wedge with high-temperature hydrous melts from the subducting slab to generate the extremely refractory harzburgites. This latter stage can be linked to the eruption of low-Ca boninites at Cape Vogel, and other arc-related volcanics, in a nascent oceanic island arc. Both ophiolites were emplaced shortly after when the embryonic oceanic island arc collided with the Australian continent.
DS200712-0873
2007
Gonzalez-Casado, J.M.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
DS201809-2029
2018
Gonzalez-Garcia, D.Gonzalez-Garcia, D., Petrelli, M., Behrens, H., Vetere, F., Fischer, L.A., Morgavi, D., Perugini, D.Diffusive exchange of trace elements between alkaline melts: implications for element fractionation and timescale estimations during magma mixing.Geochimica et Cosmochimica Acta, Vol. 233, pp. 95-114.Europe, Italyshoshonites

Abstract: The diffusive exchange of 30 trace elements (Cs, Rb, Ba, Sr, Co, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ta, V, Cr, Pb, Th, U, Zr, Hf, Sn and Nb) during the interaction of natural mafic and silicic alkaline melts was experimentally studied at conditions relevant to shallow magmatic systems. In detail, a set of 12 diffusion couple experiments have been performed between natural shoshonitic and rhyolitic melts from the Vulcano Island (Aeolian archipelago, Italy) at a temperature of 1200?°C, pressures from 50 to 500?MPa, and water contents ranging from nominally dry to ca. 2 wt.%. Concentration-distance profiles, measured by Laser Ablation ICP-MS, highlight different behaviours, and trace elements were divided into two groups: (1) elements with normal diffusion profiles (13 elements, mainly low field strength and transition elements), and (2) elements showing uphill diffusion (17 elements including Y, Zr, Nb, Pb and rare earth elements, except Eu). For the elements showing normal diffusion profiles, chemical diffusion coefficients were estimated using a concentration-dependent evaluation method, and values are given at four intermediate compositions (SiO2 equal to 58, 62, 66 and 70 wt.%, respectively). A general coupling of diffusion coefficients to silica diffusivity is observed, and variations in systematics are observed between mafic and silicic compositions. Results show that water plays a decisive role on diffusive rates in the studied conditions, producing an enhancement between 0.4 and 0.7 log units per 1 wt.% of added H2O. Particularly notable is the behaviour of the trivalent-only REEs (La to Nd and Gd to Lu), with strong uphill diffusion minima, diminishing from light to heavy REEs. Modelling of REE profiles by a modified effective binary diffusion model indicates that activity gradients induced by the SiO2 concentration contrast are responsible for their development, inducing a transient partitioning of REEs towards the shoshonitic melt. These results indicate that diffusive fractionation of trace elements is possible during magma mixing events, especially in the more silicic melts, and that the presence of water in such events can lead to enhanced chemical diffusive mixing efficiency, affecting also the estimation of mixing to eruption timescales.
DS201711-2514
2017
Gonzalez-Jimenez, J.M.Gonzalez-Jimenez, J.M., Camprubi, A., Colas, V., Griffin, W.L., Proenza, J.A., O'Reilly, S.Y., Centeno-Garcia, El., Garcia-Casco, A., Belousova, E., Talavera, C., Farre-de-Pablo, J., Satsukawa, T.The recycling of chromitites in ophiolites from southwestern North America. ( Baja)Lithos, in press available, 52p.United States, Californiachromitites

Abstract: Podiform chromitites occur in mantle peridotites of the Late Triassic Puerto Nuevo Ophiolite, Baja California Sur State, Mexico. These are high-Cr chromitites [Cr# (Cr/Cr + Al atomic ratio = 0.61-0.69)] that contain a range of minor- and trace-elements and show whole-rock enrichment in IPGE (Os, Ir, Ru). That are similar to those of high-Cr ophiolitic chromitites crystallised from melts similar to high-Mg island-arc tholeiites (IAT) and boninites in supra-subduction-zone mantle wedges. Crystallisation of these chromitites from S-undersaturated melts is consistent with the presence of abundant inclusions of platinum-group minerals (PGM) such as laurite (RuS2)-erlichmanite (OsS2), osmium and irarsite (IrAsS) in chromite, that yield TMA ? TRD model ages peaking at ~ 325 Ma. Thirty-three xenocrystic zircons recovered from mineral concentrates of these chromitites yield ages (2263 ± 44 Ma to 278 ± 4 Ma) and Hf-O compositions [?Hf(t) = ? 18.7 to + 9.1 and 18O values < 12.4‰] that broadly match those of zircons reported in nearby exposed crustal blocks of southwestern North America. We interpret these chromitite zircons as remnants of partly digested continental crust or continent-derived sediments on oceanic crust delivered into the mantle via subduction. They were captured by the parental melts of the chromitites when the latter formed in a supra-subduction zone mantle wedge polluted with crustal material. In addition, the Puerto Nuevo chromites have clinopyroxene lamellae with preferred crystallographic orientation, which we interpret as evidence that chromitites have experienced high-temperature and ultra high-pressure conditions (< 12 GPa and ~ 1600 °C). We propose a tectonic scenario that involves the formation of chromitite in the supra-subduction zone mantle wedge underlying the Vizcaino intra-oceanic arc ca. 250 Ma ago, deep-mantle recycling, and subsequent diapiric exhumation in the intra-oceanic basin (the San Hipólito marginal sea) generated during an extensional stage of the Vizcaino intra-oceanic arc ca. 221 Ma ago. The TRD ages at ~ 325 Ma record a partial melting event in the mantle prior to the construction of the Vizcaino intra-oceanic arc, which is probably related to the Permian continental subduction, dated at ~ 311 Ma.
DS201810-2324
2018
Gonzalez-Jimenez, J.M.Griffin, W.L., Howell, D., Gonzalez-Jimenez, J.M., Xiong, Q.., O'Reilly, S.Y.Comment: Ultra high pressure and ultra reduced minerals in ophiolites may form by lightning strikes. Super Reduced Minerals SURGeochemical Perspectives Letters, Vol. 7, pp. 1-2.Mantlemoissanite

Abstract: Ballhaus et al. (2017) use electric-discharge experiments to argue that lightning strikes could produce ultra-high pressure (UHP) and super-reduced (SuR) phases "identical to those found in 'high-pressure' ophiolites" and that thus there is "not sufficient evidence to challenge long-established models of ophiolite genesis", specifically for the UHP processing of Tibetan ophiolites. However, the authors produced no evidence for UHP phases in their experiments. There are pertinent observations, relevant to the authors’ assertions, in the literature regarding the relationship between the UHP and SuR assemblages in the Tibetan peridotites. Their conclusions are not consistent with this evidence.
DS201312-0320
2013
Gonzalez-Jimienez, J.M.Gonzalez-Jimienez, J.M., Marchesi, C., Griffin, W.L., Gutierrez-Narbona, R., Lorand, J-P., O'Reilly, S.Y., Garrido, C.J., Gervilla, F., Pearson, N.J., Hidas, K.Transfer of Os isotopic signatures from peridotite to chromitite in the subcontinental mantle: insights from in situ analysis of platinum-group and base metal minerals (Ojen peridotite massif, southern Spain.Lithos, Vol. 164-167, pp. 74-85.Europe, SpainChromitite
DS201312-0322
2013
Gonzalez-Jimienez, J.M.Gonzalez-Jimienez, J.M., Griffin, W.L., Gervilla, F., Proenza, J.A., O'Reilly, S.Y., Pearson, N.J.Chromitites in ophiolites: how, where, when, why? Part 1. A review of new ideas on the origin and significance of platinum-group minerals.Lithos, Vol. 189, pp. 127-139.MantleGeodynamics
DS201503-0166
2015
Gonzalez-Jiminez, J.M.Pasava, J., Malec, J., Griffin, W.L., Gonzalez-Jiminez, J.M.Re-Os isotopic constraints on the source of platinum-group minerals (PGMs) from the Vestrev pyrope rich garnet placer deposit, Bohemian Massif.Ore Geology Reviews, Vol. 68, pp. 117-1326EuropeGarnet mineralogy
DS201606-1090
2016
Gonzalez-Jiminez, J.M.Griffin, W.L., Afonso, J.C., Belousova, E.A., Gain, S.E., Gong, X-H., Gonzalez-Jiminez, J.M., Howell, D., Huang, J-X., McGowan, N., Pearson, N.J., Satsukawa, T., Shi R., Williams, P., Xiong, Q., Yang, J-S., Zhang, M., O'Reilly, S.Y.Mantle recycling: transition zone metamorphism of Tibetan ophiolitic peridotites and its tectonic implications.Journal of Petrology, in press available, 30p.Asia, China, TibetPeridotite

Abstract: Large peridotite massifs are scattered along the 1500?km length of the Yarlung-Zangbo Suture Zone (southern Tibet, China), the major suture between Asia and Greater India. Diamonds occur in the peridotites and chromitites of several massifs, together with an extensive suite of trace phases that indicate extremely low fO2 (SiC, nitrides, carbides, native elements) and/or ultrahigh pressures (UHP) (diamond, TiO2 II, coesite, possible stishovite). New physical and isotopic (C, N) studies of the diamonds indicate that they are natural, crystallized in a disequilibrium, high-T environment, and spent only a short time at mantle temperatures before exhumation and cooling. These constraints are difficult to reconcile with previous models for the history of the diamond-bearing rocks. Possible evidence for metamorphism in or near the upper part of the Transition Zone includes the following: (1) chromite (in disseminated, nodular and massive chromitites) containing exsolved pyroxenes and coesite, suggesting inversion from a high-P polymorph of chromite; (2) microstructural studies suggesting that the chromitites recrystallized from fine-grained, highly deformed mixtures of wadsleyite and an octahedral polymorph of chromite; (3) a new cubic Mg-silicate, with the space group of ringwoodite but an inverse-spinel structure (all Si in octahedral coordination); (4) harzburgites with coarsely vermicular symplectites of opx + Cr-Al spinel ± cpx; reconstructions suggest that these are the breakdown products of majoritic garnets, with estimated minimum pressures to?>?13?GPa. Evidence for a shallow pre-metamorphic origin for the chromitites and peridotites includes the following: (1) trace-element data showing that the chromitites are typical of suprasubduction-zone (SSZ) chromitites formed by magma mixing or mingling, consistent with Hf-isotope data from magmatic (375?Ma) zircons in the chromitites; (2) the composition of the new cubic Mg-silicate, which suggests a low-P origin as antigorite, subsequently dehydrated; (3) the peridotites themselves, which carry the trace element signature of metasomatism in an SSZ environment, a signature that must have been imposed before the incorporation of the UHP and low-fO2 phases. A proposed P-T-t path involves the original formation of chromitites in mantle-wedge harzburgites, subduction of these harzburgites at c. 375?Ma, residence in the upper Transition Zone for >200 Myr, and rapid exhumation at c. 170-150?Ma or 130-120?Ma. Os-isotope data suggest that the subducted mantle consisted of previously depleted subcontinental lithosphere, dragged down by a subducting oceanic slab. Thermomechanical modeling shows that roll-back of a (much later) subducting slab would produce a high-velocity channelized upwelling that could exhume the buoyant harzburgites (and their chromitites) from the Transition Zone in?
DS201909-2038
2019
Gonzalez-Jiminez, J.M.Farre-de-Pblo, J., Proenza, J.A., Gonzalez-Jiminez, J.M., Garcia-Casco, A., Colas, V., Roque-Rosell, J., Camprubi, A., Sanchez-Navas, A.A shallow origin for diamonds in ophiolitic chromitites. Geology, Vol. 47, pp. e477-478.North America, Mexicomicrodiamonds

Abstract: Recent findings of diamonds in ophiolitic peridotites and chromitites challenge our traditional notion of Earth mantle dynamics. Models attempting to explain these findings involve incorporation of diamonds into chromite near the mantle transition zone. However, the occurrence of metastable diamonds in this context has not been considered. Here, we report for the first time in situ microdiamonds in chromite from ophiolitic chromitite pods hosted in the Tehuitzingo serpentinite (southern Mexico). Here, diamonds occur as fracture-filling inclusions along with quartz, clinochlore, serpentine, and amorphous carbon, thus indicating a secondary origin during the shallow hydration of chromitite. Chromite chemical variations across the diamond-bearing healed fractures indicate formation during the retrograde evolution of chromitite at temperatures between 670 °C and 515 °C. During this stage, diamond precipitated metastably at low pressure from reduced C-O-H fluids that infiltrated from the host peridotite at the onset of serpentinization processes. Diamond was preserved as a result of fracture healing at the same temperature interval in which the chromite alteration began. These mechanisms of diamond formation challenge the idea that the occurrence of diamond in ophiolitic rocks constitutes an unequivocal indicator of ultrahigh-pressure conditions.
DS202010-1869
2020
Gonzalez-Jiminez, J.M.Pujol-Sola, N., Garcia-Casco, A., Proenza, J.A., Gonzalez-Jiminez, J.M., del Camp, A., Colas, V., Canals, A., Sanchez-Navas, A., Roque-Rosell, J.Diamond forms during low pressure serpentinisation of oceanic lithosphere.Geochemical Perspectives Letters, 7p. PdfCentral America, Cubadiamond genesis

Abstract: Diamond is commonly regarded as an indicator of ultra-high pressure conditions in Earth System Science. This canonical view is challenged by recent data and interpretations that suggest metastable growth of diamond in low pressure environments. One such environment is serpentinisation of oceanic lithosphere, which produces highly reduced CH4-bearing fluids after olivine alteration by reaction with infiltrating fluids. Here we report the first ever observed in situ diamond within olivine-hosted, CH4-rich fluid inclusions from low pressure oceanic gabbro and chromitite samples from the Moa-Baracoa ophiolitic massif, eastern Cuba. Diamond is encapsulated in voids below the polished mineral surface forming a typical serpentinisation array, with methane, serpentine and magnetite, providing definitive evidence for its metastable growth upon low temperature and low pressure alteration of oceanic lithosphere and super-reduction of infiltrated fluids. Thermodynamic modelling of the observed solid and fluid assemblage at a reference P-T point appropriate for serpentinisation (350 °C and 100 MPa) is consistent with extreme reduction of the fluid to logfO2 (MPa) = ?45.3 (?logfO2[Iron-Magnetite] = ?6.5). These findings imply that the formation of metastable diamond at low pressure in serpentinised olivine is a widespread process in modern and ancient oceanic lithosphere, questioning a generalised ultra-high pressure origin for ophiolitic diamond.
DS201212-0204
2012
Gonzalez-LodeiroFlor De Lis, M., Stitch, Morales, Juli, Diaz, Cordoba, Pulgar, Ibarra, Harnafi, Gonzalez-LodeiroCrustal thickness variations in northern Morocco.Journal of Geophysical Research, Vol. 117, B2, B02312.Africa, MoroccoGeophysics - seismics
DS202205-0673
2022
Gonzalqez-Alvarez, I.Barrett, N., Jaques, A.L., Gonzalqez-Alvarez, I., Walter, M.J., Pearson, G.Ultra-refractory peridotites of Phanerozoic mantle origin: the Papua New Guinea ophiolite mantle tectonites.Journal of Petrology, 10.1093/petrology/egac014 99p. pdf Asia, Papua New Guineatectonites

Abstract: Harzburgites and dunites forming the base of the Late Cretaceous-Paleocene Papuan Ultramafic Belt (PUB) and Marum ophiolites of Papua New Guinea (PNG) are among the most refractory mantle peridotites on Earth. We present a new integrated dataset of major element, bulk plus mineral trace element and Re-Os isotopic analyses aimed at better understanding the genesis of these peridotites. The PUB harzburgites contain olivine (Fo92-93), low-Al enstatite (less than or equal to 0.5 wt. % Al2O3 and CaO), and Cr-rich spinel (Cr#?=?0.90-0.95). The Marum harzburgites are less refractory with olivine (Fo91.9-92.7), enstatite (~0.5-1.0 wt. % Al2O3 and CaO), minor clinopyroxene (diopside), and spinel (Cr#?=?0.71-0.77). These major element characteristics reflect equivalent or greater levels of melt depletion than that experienced by Archean cratonic peridotites. Whereas bulk-rock heavy rare earth element (HREE) abundances mirror the refractory character indicated by the mineral chemistry and major elements, large-ion lithophile elements indicate a more complex melting and metasomatic history. In situ olivine and orthopyroxene REE measurements show that harzburgites and dunites have experienced distinct melt-rock interaction processes, with dunite channels/lenses, specifically, showing higher abundances of HREE in olivine. Distinctive severe inter-element fraction of platinum group elements and Re result in complex patterns that we refer to as ‘M-shaped’. These fractionated highly siderophile element (HSE) patterns likely reflect the dissolution of HSE-rich phases in highly depleted peridotites by interaction with subduction-related melts/fluids, possibly high-temperature boninites. Osmium isotope compositions of the PNG peridotites are variable (187Os/188Os?=?0.1204 to 0.1611), but fall within the range of peridotites derived from Phanerozoic oceanic mantle, providing no support for ancient melt depletion, despite their refractory character. This provides further evidence that highly depleted peridotites can be produced in the modern Earth, in subduction zone environments. The complex geochemistry indicates a multi-stage process for the formation of the PNG mantle peridotites in a modern geodynamic environment. The first stage involves partial melting at low-pressure (<2 GPa) and high-temperature (~1250°C-1350°C) to form low-K, low-Ti tholeiitic magmas that formed the overlying cumulate peridotite-gabbro and basalt (PUB only) sequences of the ophiolites. This is inferred to have occurred in a fore-arc setting at the initiation of subduction. Later stages involved fluxing of the residual harzburgites with hydrous fluids and melts to form replacive dunites and enstatite dykes and interaction of the residual peridotites in the overlying mantle wedge with high-temperature hydrous melts from the subducting slab to generate the extremely refractory harzburgites. This latter stage can be linked to the eruption of low-Ca boninites at Cape Vogel, and other arc-related volcanics, in a nascent oceanic island arc. Both ophiolites were emplaced shortly after when the embryonic oceanic island arc collided with the Australian continent.
DS1989-0526
1989
Good, D.J.Good, D.J., Crocket, J.H.platinum group elements (PGE) study of the Geordie Lake and Marathon copper-nickel precious metal Coldwell Alkalic ComplexOntario Geological Survey miscellaneous Paper, No. 143, pp. 186-198OntarioAlkaline rocks, Coldwell Lake Complex
DS1994-0638
1994
Good, D.J.Good, D.J., Crocket, J.H.Origin of the albite pods in the Geordie Lake gabbro, Port Coldwell alkaline complex.Canadian Mineralogist, Vol. 32, No. 3, Sept. pp. 681-702.OntarioAlkaline rocks, Deposit -Port Coldwell
DS1994-0639
1994
Good, D.J.Good, D.J., Crocket, J.H.Genesis Marathon copper Platinum Group element deposit, Port Coldwell complex:Mid-continent rift related magmatic sulfide deposit.Economic Geology, Vol. 89, No. 1, Jan-Feb. pp. 131-149.OntarioAlkaline rocks, Port Coldwell Alkaline Complex
DS201612-2284
2016
Good, D.J.Cao, Y.H., Linnen, R.L., Good, D.J., Samson, I.M., Epstein, R.The application of portable XRF and benchtop SEM-EDS to Cu-Pd exploration in the Coldwell alkaline complex, Ontario, Canada.Geochemistry: Exploration, Environment, Analysis, Vol. 16, 3-4, pp. 193-212.Canada, OntarioAlkalic

Abstract: Mineral exploration is increasingly taking advantage of real time techniques that dramatically reduce the costs and time taken to obtain results compared to traditional analytical methods. Portable X-ray fluorescence (pXRF) is now a well-established technique that is used to acquire lithogeochemical data. To date, however, benchtop scanning electron microscopes, equipped with energy dispersive systems (bSEM-EDS) have received little attention as a possible mineral exploration tool. This study examines the utility of combining pXRF and bSEM-EDS to characterize the igneous stratigraphy and its relationship to Cu-Pd mineralization in a drill hole at the Four Dams occurrence, located within the Eastern Gabbro assemblage of the Coldwell Alkaline Complex, Canada. The first part of this study compares field portable and laboratory techniques. Seventy-two powdered samples analysed by pXRF are compared with traditional major elements analysed by inductively coupled atomic emission spectroscopy (ICP-AES) and trace elements by inductively coupled plasma spectrometry (ICP-MS), and the compositions of 128 olivine, clinopyroxene and plagioclase grains analysed by bSEM-EDS are compared with traditional electron microprobe data. Our results show that each portable technique yields results similar to their lab-based counterparts within the analytical capabilities and precisions of the respective instruments. The second part presents a case study for the application of pXRF and bSEM-EDS to resolve questions related to igneous stratigraphy as an aid to mineral exploration in a complicated geological setting. A major problem for Cu-Pd exploration in the Coldwell Complex of NW Ontario is that the oxide-rich units that host Cu-Pd mineralization in the Marathon Series are petrographically similar to the barren oxide-rich units in the Layered Series. However, the mineralized units are geochemically distinctive. Our results show that the mineralized Marathon Series can be distinguished from the barren Layered Series, including oxide-rich units of both, by combinations of P2O5, Ba, Zr and V/Ti values, determined by pXRF, combined with plagioclase, olivine or clinopyroxene compositions measured by bSEM-EDS. The combination of pXRF and bSEM-EDS thus shows considerable promise as an exploration technique.
DS201706-1073
2017
Good, D.J.Good, D.J., Cabri, L.J., Ames, D.E.PGM facies variations for Cu-PGE deposits in the Coldwell alkaline complex, Ontario, Canada.Ore Geology Reviews, in press available 36p.Canada, Ontarioalkaline rocks

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

Abstract: The W Horizon, Marathon Cu-Pd deposit in the Mesoproterozoic Midcontinent rift is one of the highest grade PGE repositories in magmatic ore deposits world-wide. The textural relationships and compositions of diverse platinum-group mineral (PGM) and sulfide assemblages in the extremely enriched ores (>100 ppm Pd-Pt-Au over 2 m) of the W Horizon have been investigated in mineral concentrates with ?10,000 PGM grains and in situ using scanning electron microprobe and microprobe analyses. Here we show, from ore samples with concentrations up to 23.1 Pd ppm, 8.9 Pt ppm, 1.4 Au ppm and 0.73 Rh ppm, the diversity of minerals (n = 52) including several significant unknown minerals and three new mineral species marathonite (Pd25Ge9; McDonald et al., 2016), palladogermanide (Pd2Ge; IMA 2016-086, McDonald et al., 2017), kravtsovite (PdAg2S, IMA No 2016-092, Vymazalová et al., 2017). The PGM are distributed as PG-, sulfides (52 vol%), -arsenides (34 vol%), -intermetallics of Au-Ag-Pd-Cu and Pd-Ge(10 vol%) and -bismuthides and tellurides (4 vol%). The discovery of abundant (>330 grains) large unknown sulfide minerals with Rh allows us to present analyses three significant potentially new minerals (WUK-1, WUK-2, WUK-3) that are all clearly enriched in Rh (averaging 4.2, 8.5 and 28.21 wt% Rh respectively). Several examples of paragenetic sequences and mineral chemical changes for enrichment of Cu, Pd and Rh with time are revealed in the PGM and base-metal sulfides. We suggest this enhanced metal enrichment formed in response to increasing fO2 causing the oxidation of Fe2+ to Fe3+ and to a lesser extent, S. Phase relations in the Ag-Pd-S, Rh-Ni-Fe-S, Pd-Ge, Au-Pd-Cu-Ag, Pd-Ag-Te systems help constrain the crystallization temperatures of the majority of ore minerals in the W Horizon at ?500 °C or moderate to high subsolidus temperatures (400–600 °C). Local transport by aqueous fluids becomes evident as minerals recrystallize down to <300 °C. The PGE-enriched W Horizon ores exhibit a complex post-magmatic history dominated by the effects of oxidation during cooling of a Cu-PGE enriched magma source from a deep reservoir.
DS202104-0567
2021
Good, D.J.Brzozowski, M., Samson, I.M., Gagnon, J.E., Linnen, R.L., Good, D.J.Effects of fluid-induced oxidation on the composition of Fe-Ti oxides in the eastern gabbro, Coldwell Complex, Canada: implications for the application of Fe-Ti oxides to petrogenesis and mineral exploration.Mineralium Deposita, Vol. 56, pp. 601-618. pdfCanada, Ontariodeposit - Coldwell

Abstract: Magnetite (mag)-ilmenite (ilm) intergrowths are more common than mag-ulvöspinel (usp) intergrowths in mafic-ultramafic Ni-Cu-PGE systems, yet the former has no known solid solution. The most accepted model for the formation of mag-ilm intergrowths in terrestrial environments is fluid-induced oxidation of mag-usp assemblages by oxygen in water. In this study, we re-examine this model in light of the fact that crustal fluids have very low pO2 and that mag-ilm intergrowths commonly occur in rocks that show little or no evidence of hydrothermal alteration. We also characterize the chemical changes that occurred during the formation of mag-ilm intergrowths and how they affect the use of Fe-Ti oxide chemistry for petrogenesis and mineral exploration. In the Eastern Gabbro, Coldwell Complex, a continuum of Fe-Ti oxide intergrowths occur ranging from cloth (mag-usp) to trellis (mag-ilm) types. Trellis-textured intergrowths have higher bulk Fe3+:Fe2+ ratios and are predominantly enriched not only in some multivalent (Ge, Mo, W, Sn) elements, but also in Cu and Ga, consistent with their formation via oxidation by a metal-rich fluid. These compositional changes are significant relative to typical elemental abundances in Fe-Ti oxides and could potentially lead to erroneous interpretations regarding primary magmatic processes if they are not taken into consideration. The irregular distribution of the intergrowths throughout the Eastern Gabbro suggests that different rock series and mineralized zones experienced variable degrees of fluid-induced oxidation. It is proposed that C in CO2 rather than O2 in water could potentially be an important oxidizing agent in mafic systems: 9Fe2+2TiO4+0.75CO2+1.5H2O?9Fe2+TiO3+3Fe3+2Fe2+O4+0.75CH4. The applicability of this model is supported by the common occurrence of CO2 and CH4 in fluid inclusions in mafic rocks.
DS202104-0568
2021
Good, D.J.Brzozowski, M.J., Samson, I.M., Gagnon, J.E., Good, D.J., Linnen, R.L.Oxide mineralogy and trace element chemistry as an index to magma evolution and Marathon-type mineralization in the eastern gabbro of the alkaline Coldwell Complex, Canada.Mineralium Deposita, Vol. 56, pp. 621-642. pdfCanada, Ontariodeposit - Coldwell

Abstract: The Eastern Gabbro of the alkaline Coldwell Complex, Canada, represents a Ni-poor conduit-type system that comprises two rock series, the Layered Series and Marathon Series, which intruded into a metabasalt package. Based on distinct variations in magnetite compatible (e.g., Ni, Cr) and incompatible (e.g., Sn, Nb) elements in Fe-Ti oxide intergrowths, the metabasalts, Layered Series, and Marathon Series must have crystallized from magmas that originated from compositionally distinct sources. Of these rock units, the metabasalts crystallized from a more primitive melt than the Layered Series as Fe-Ti oxides in the former have higher concentrations of magnetite-compatible elements. Unlike the metabasalts and Layered Series, the Marathon Series crystallized from multiple, compositionally distinct magmas as Fe-Ti oxides in this series exhibit large variations in both magnetite compatible and incompatible elements. Accordingly, the various rock types of the Marathon Series cannot be related by fractional crystallization of a single batch of magma. Rather, the magmas from which the rock types crystallized had to have interacted to variable degrees with a late input of more primitive melt. The degree of this magma interaction was likely controlled by the geometry of the conduit and the location of emplacement given that Fe-Ti oxides in the oxide-rich rocks occur in pod-like bodies and exhibit no compositional evidence for magma mixing. Mirrored variations in magnetite compatible and incompatible elements in Fe-Ti oxides in the Footwall Zone, Main Zone, and W Horizon of the Marathon Cu-PGE deposit indicate that these zones could not have formed from a single, evolving magma, but rather multiple batches of compositionally distinct magmas. Fe-Ti oxides exhibit no compositional difference between those hosted by barren and mineralized rock. This is likely because sulfide liquated at depth in all of the magmas from which the Marathon Series crystallized. The composition of Fe-Ti oxides in the Eastern Gabbro fall outside of the compositional fields for Ni-Cu mineralization defined by Dupuis and Beaudoin (Mineral Deposita 46:319-335, 2011) and Ward et al. (J Geochem Explor 188:172-184, 2018) demonstrating that their discrimination diagrams can distinguish between Ni-rich and Ni-poor systems that contain disseminated and massive sulfides.
DS202109-1469
2021
Good, D.J.Good, D.J., Hollings, P., Dunning, G., Epstein, R., McBride, J., Jedemann, A., Magnus, S., Bohav, T., Shore, G.A new model for the Coldwell Complex and associated dykes of the Midcontinent Rift, Canada.Journal of Petrology, Vol. 62, 7, 10.1093/petrology/ega036Canadadeposit - Coldwell

Abstract: Mafic intrusions on the NE shoulder of the Midcontinent Rift (Keweenawan LIP), including Cu-PGE mineralized gabbros within the Coldwell Complex (CC), and rift parallel or radial dykes outside the CC are correlated based on characteristic trace element patterns. In the Coldwell Complex, mafic rocks are subdivided into four groups: (1) early metabasalt; (2) Marathon Series; (3) Layered Series; (4) Geordie-Wolfcamp Series. The Marathon Series are correlated with the rift radial Abitibi dykes (1140?Ma), and the Geordie-Wolfcamp Series with the rift parallel Pukaskwa and Copper Island dykes. U-Pb ages determined for five gabbros from the Layered and Marathon Series are between 1107•7 and 1106•0?Ma. Radiogenic isotope ratios show near chondritic (CHUR) ?Nd(1106?Ma) and 87Sr/86Sri values that range from -0•38 to +1•13 and 0•702537 to 0•703944, respectively. Distinctive geochemical properties of the Marathon Series and Abitibi dykes, such as Ba/La (14-37), Th/Nb (0•06-0•12), La/Sm (3•8-7•7), Sr/Nd (21-96) and Zr/Sm (9-19), are very different from those of the Geordie-Wolfcamp Series and a subset of Copper Island and Pukaskwa dykes with Ba/La (8•7-11), Th/Nb (0•12-0•13), La/Sm (6•7-7•9), Sr/Nd (5-7•8) and Zr/Sm (18-24). Each unit exhibits covariation between incompatible element ratios such as Zr/Sm and Nb/La or Gd/Yb, Sr/Nd and Ba/La, and Nb/Y and Zr/Y, which are consistent with mixing relationship between two or more mantle domains. These characteristics are unlike those of intrusions on the NW shoulder of the MCR, but resemble those of mafic rocks occurring in the East Kenya Rift. The results imply that an unusual and long-lived mantle source was present in the NE MCR for at least 34?Myr (spanning the 1140?Ma Abitibi dykes and the 1106?Ma Marathon series) and indicate potential for Cu-PGE mineralization in an area much larger than was previously recognized.
DS1981-0098
1981
Good, R.Brewer, J.A., Good, R., Brown, L.D., Oliver, J.E., Kaufman, S.Cocorp Seismic Reflection Traverse Across the Southern Oklahoma Aulacogen.Geological Society of America (GSA), Vol. 13, No. 7, P. 416. (abstract.).OklahomaMid-continent
DS1982-0119
1982
Good, R.Brewer, J.A., Good, R., Oliver, J.E., Brown, L.D., Kaufman, S.Cocorp Deep Seismic Reflection Profiling of the Southern Oklahoma Aulacogen.Geological Society of America (GSA), Vol. 14, No. 3, P. 106. (abstract.).OklahomaMid-continent, Geophysics
DS1983-0147
1983
Good, R.Brewer, J.A., Good, R., Oliver, J.E., Brown, L.D., Kaufman, S.Cocorp Profiling Across the Southern Oklahoma Aulacogen: Over thrusting of the Wichita Mountains and Compression Within The Anadarko Basin.Geology, Vol. 11, No. 2, PP. 109-114.OklahomaMid-continent, Geophysics
DS1983-0258
1983
Good, R.Good, R., Brown, L., Oliver, J., Kaufman, S.Cocorp Deep Seismic Reflection Traverse Across the southern Oklahoma Aulocogen.American Association of Petroleum Geologists (AAPG) STUDIES IN GEOLOGY, No. 15, PP. 3.2.2-33- 3.2.2.-37.OklahomaMid-continent
DS1960-0760
1966
Goodacre, A.K.Weber, J.R., Goodacre, A.K.A Reconnaissance Under Water Gravity Survey of Lake SuperiorAmerican GEOPHYS. MONOGRAPH, No. 10, PP. 55-65.GlobalMid-continent, Geophysics
DS1989-0547
1989
Goodacre, A.K.Grieve, R.A.F., Adams, J., Goodacre, A.K., Nevitt, L., TeskeyThe Canadian geophysical atlasGeological Society of Canada (GSC) Forum 1989, P. 12 abstractOntarioGeophysical atlas
DS1991-1448
1991
Goodacre, A.K.Roest, W.R., Rupert, J.D., Grieve, R.A.F., Goodacre, A.K.Structural aspects of North America in the context of the World Bougueranomaly mapGeological Survey of Canada Forum held January 21-23, 1990 in Ottawa, p. 14 AbstractGlobalGeophysics -Gravity, Map
DS1993-0559
1993
Goodacre, A.K.Goodacre, A.K., Bonham-Carter, G.F., Agterberg, F.P., Wrightm D.F.A statistical analysis of the spatial association of seismicity with drainage patterns and magnetic anomalies in western QuebecTectonophysics, Vol. 217, No. 3-4, January 30, pp. 285-306QuebecGeomorphology, Geophysics -seismics
DS1995-0529
1995
Goodacre, A.K.Feininger, T., Goodacre, A.K.The eight classical Montregian hills at depth and the mechanism of theirintrusion.Canadian Journal of Earth Sciences, Vol. 32, No. 9, Sept. pp. 1350-1364.QuebecGeophysics -gravity Alkaline rocks, Deposit - Montregian Hills area
DS201708-1652
2017
Goodarzi, P.Goodarzi, P.Oxygen fugacity as a control on the distribution of diamond in the sub-cratonic lithospheric mantle.11th. International Kimberlite Conference, PosterMantleBlank
DS201709-1991
2017
Goodarzi, P.Y.Goodarzi, P.Y., Berry, A.J., Pearson, D.G., Yaxley, G.M., Newville, M.Garnet as a recorder of metasomatism in the sub-continental lithospheric mantle. Goldschmidt Conference, abstract 1p.Africa, Namibiadeposit , Louwerensia

Abstract: Metasomatism by fluid or melt is commonly attributed as the cause of chemical and modal heterogeneity observed in peridotite xenoliths from the sub-continental lithospheric mantle. Documented manifestations are (1) perturbation of the oxygen fugacity (fO2), which may affect the stability of carbon-bearing phases, and (2) trace-element enrichment, typified by the shape of REEN patterns. Garnet, which contains Fe2+ and Fe3+ in measurable quantities, and exhibits prominent variation in REEN patterns between samples, may record the metasomatic history of the mantle. Here we report variations of fO2 and trace element concentrations for a suite of 22 garnet-bearing peridotite xenoliths from the Louwrensia kimberlite, south-central Namibia. The xenoliths span an estimated pressure range between 2.7 and 4.5 GPa. Fe3+/?Fe of garnet was determined by Fe K-edge XANES spectroscopy. Concomitant fO2 was calculated using the oxybarometer calibration of Miller et al. [1]. The trace element concentrations of all phases were determined by LA-ICP-MS. A global dataset comprising 454 garnet REEN patterns from 19 kimberlites has been compiled. The REEN pattern of each sample was fit to orthogonal polynomial functions that parameterise the abundance, slope, quadratic curvature, and cubic curvature [2]. Quadratic and cubic curvature correlate with abundance, albeit with considerable scatter. There is, however, an absence of correlation between REEN patterns and fO2, depth, or modal abundance. This is in contrast to correlations and trends observed for basaltic melts that clearly identify petrogenetic trends. The partitioning of REEs between garnet and co-existing phases in these samples highlights pronounced trace-element disequilibrium and hence question the validity of considering garnet REEN in isolation as a means of discerning metasomatic history
DS200912-0257
2008
Goodch, T.M.Goodch, T.M.Conflict diamonds or illicit diamonds: should the difference matter to the Kimberley Process Certification scheme?Natural Resources Forum, Vol. 48, 1, pp. 189-214.GlobalLegal
DS1991-1037
1991
Goodchild, M.F.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
DS1992-0586
1992
Goodchild, M.F.Goodchild, M.F.Geographical dat a modelingComputers and Geosciences, Vol. 18, No. 4, pp. 401-408GlobalComputer, Programs -Geographic information systems -data
DS1997-0426
1997
Goodchild, M.F.Goodchild, M.F., et al.GIS and environmental modeling: progress and research issuesEarth Observation Magazine books, $ 80.00GlobalBook - ad, GIS - environment
DS1900-0664
1908
Goodchild, W.Goodchild, W.Precious Stones (1908)London: Van Nostrand., GlobalKimberlite, Kimberley, Janlib, Gemology
DS202102-0195
2020
Goodden, R.Goodden, R.Ocean diamonds - alluvialsGems & Jewellery, Vol. 29, 4, pp. 14-16. pdfAfrica, Namibiaalluvials
DS1994-0640
1994
Goode, J.Goode, J., King, E., Smith, L.D.Global opportunities and risks in mining -the consulting engineers'perspectiveThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 87, No. 982, July/August pp. 82-94GlobalEconomics, Mining risks
DS1991-0588
1991
Goode, J.R.Goode, J.R., Davie, M.J., Smith, L.D., Lattanzi, C.R.Back to basics: the feasibility studyThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 84, No. 953, September pp. 53-61GlobalEconomics, Valuation
DS1986-0296
1986
Goodell, P.C.Goodell, P.C., Keller, G.R., Dyer, J.B.The Sierra Del Nido tectonic block- a newly recognized cratonic feature In northern MexicoGeological Society of America (GSA) (Abstract Volume), Vol. 18, No. 6, p. 618. (abstract.)MexicoTectonics
DS2002-0593
2002
Goodeneough, K.M.Goodeneough, K.M., Upton, B.G.J., Ellam, R.M.Long term memory of subduction processes in the lithospheric mantle: evidence from geochemistry of basic dykes in the Gardar Province of South Greenland.Journal of the Geological Society of London, Vol. 159, 6, pp. 705-714.GreenlandBlank
DS201112-0516
2011
Goodenough, et al.Key, R.M., Pitfield, P.E.J., Thomas, R.J., Goodenough, et al.Polyphase neoproterozoic orogenesis within the East Africa-Antarctica orogenic belt in central and northern Madagascar.The Formation and Evolution of Africa: A synopsis of 3.8 Ga of Earth History, Geol. Soc. London Special Publ., 357, pp. 49-68.Africa, MadagascarOrogeny
DS201906-1351
2019
Goodenough, K.Smith, M.P., Estrade, G., Marquis, E., Goodenough, K., Nason, P., Xu, C., Kynicky, J., Borst, A.M., Finch, A.A., Villanova de Benevent, C.Ion adsorption deposits: a comparison of deposits in Madagascar and China.3rd International Critical Metals Meeting held Edinburgh, 1p.abstract p. 53.Africa, Madagascar, ChinaREE

Abstract: Link to presentation pdf.
DS201909-2037
2019
Goodenough, K.Estrade, G., Marquis, E., Smith, M., Goodenough, K.,Nason, P.REE concentration processes in ion absorption deposits: evidence from the Ambohimirahavavy alkaline complex in Madagascar.Ore Geology Reviews, in press available, 21p. pdfAfrica, MadagascarREE
DS202104-0570
2021
Goodenough, K.Charles, N., Tuduri, J., Lefebvre, G., Pourret, O., Gaillard, F., Goodenough, K.Ressources en terres rares de l'Europe et du Groenland: un potential minier remarquable mais tabou?In: Boulvais, P., Decree, S. Eds. Ressources metalliques: cadre geodynamique et exemples remarquables. ISTE Science Pub. Researchgate, 97p. pdfEurope, GreenlandREE
DS202203-0348
2021
Goodenough, K.Goodenough, K., Mills, K.Reflecting on the colonial legacy of Geoscience in Africa. Dawson and Oldoinyo LengaiElements, Vol. 17, (5) p. 302.Africa, Tanzaniahistory
DS2002-0594
2002
Goodenough, K.M.Goodenough, K.M., Coulson, I.M.Carbonatites and lamprophyres in the Gardar igneous province of SW Greenland: 'windows' to the sub-Gardar mantle.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.245.GreenlandTectonics
DS2002-0595
2002
Goodenough, K.M.Goodenough, K.M., Upton, B.G.J., Ellam, R.M.Long tern memory of subduction processes in the lithospheric mantle: evidence from theJournal of the Geological Society of London, Vol. 159, 6, pp. 705-14.GreenlandTectonics - subduction
DS2003-0290
2003
Goodenough, K.M.Coulson, I.M., Goodenough, K.M., Pearce, N.J.G., Leng, M.J.Carbonatites and lamprophyres of the Gardar Province - a window to the sub-GardarMineralogical Magazine, Vol. 67, 5, pp. 855-872.GreenlandCarbonatite
DS2003-0483
2003
Goodenough, K.M.Goodenough, K.M., Coulson, I.M., Wall, F.Intraplate alkaline magmatism: mineralogy and petrogenesisMineralogical Magazine, Vol. 67, 5, pp. 829-30.GlobalAlkaline rocks
DS2003-1398
2003
Goodenough, K.M.Upton, B.G., Emeleus, C.H., Heaman, L.M., Goodenough, K.M., Finch, A.A.Magmatism of the mid-Proterozoic Gardar Province, South Greenland: chronologyLithos, Vol. 68, 1-2, pp. 43-65.GreenlandMagmatism
DS2003-1400
2003
Goodenough, K.M.Upton, B.G.J., Emeleus, C.H., Heaman, L.M., Goodenough, K.M., Finch, A.A.Magmatism of the mid-Proterozoic Gardar Province, south Greenland: chronologyLithos, Vol. 68, May, pp. 43-65.GreenlandDyke swarms, basalts
DS200412-0377
2003
Goodenough, K.M.Coulson, I.M., Goodenough, K.M., Pearce, N.J.G., Leng, M.J.Carbonatites and lamprophyres of the Gardar Province - a window to the sub-Gardar mantle?Mineralogical Magazine, Vol. 67, 5, pp. 855-72.Europe, GreenlandCarbonatite
DS200412-0693
2003
Goodenough, K.M.Goodenough, K.M., Coulson, I.M., Wall, F.Intraplate alkaline magmatism: mineralogy and petrogenesis.Mineralogical Magazine, Vol. 67, 5, pp. 829-30.TechnologyAlkalic
DS200412-0694
2002
Goodenough, K.M.Goodenough, K.M., Upton, B.G.J., Ellam, R.M.Long tern memory of subduction processes in the lithospheric mantle: evidence from the geochemistry of basic dykes in the Gardar Province of South Greenland.Journal of the Geological Society, Vol. 159, 6, pp. 705-714.Europe, GreenlandSubduction - geochemistry
DS200412-2024
2003
Goodenough, K.M.Upton, B.G., Emeleus, C.H., Heaman, L.M., Goodenough, K.M., Finch, A.A.Magmatism of the mid-Proterozoic Gardar Province, South Greenland: chronology, petrogenesis and geological setting.Lithos, Vol. 68, 1-2, pp. 43-65.Europe, GreenlandMagmatism
DS200412-2026
2003
Goodenough, K.M.Upton, B.G.J., Emeleus, C.H., Heaman, L.M., Goodenough, K.M., Finch, A.A.Magmatism of the mid-Proterozoic Gardar Province, south Greenland: chronology, petrogenesis and geological setting.Lithos, Vol. 68, May, pp. 43-65.Europe, GreenlandDyke swarms, basalts
DS201412-0305
2014
Goodenough, K.M.Goodenough, K.M., Deady, E.A., Shaw, R.A.The potential for REE deposits associated with alkaline and carbonatitic magmatism in Europe.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, http://alkaline2014.comEuropeCarbonatite
DS201412-0805
2014
Goodenough, K.M.Shervais, J.W., Arndt, N., Goodenough, K.M.Drilling the solid earth: global geodynamic cycles and earth evolution.International Journal of Earth Sciences, Vol. 104, 6, pp. 1573-1587.MantleGeodynamics - tectonics
DS201709-1992
2017
Goodenough, K.M.Goodenough, K.M., Shaw, R., Deady, E.Interaction of alkaline magmatism and carbonatites: a recipe for REE enrichment?Goldschmidt Conference, abstract 1p.Mantlecarbonatites

Abstract: The rare earth elements (REE) are critical metals that have been the subject of considerable recent research. In the published literature, REE deposits are typically divided into classes, which commonly include ‘alkaline igneous rocks’ and ‘carbonatites’ [1]. However, our recent work, carried out as part of the EURARE and HiTech AlkCarb projects, suggests that many deposits of the REE and other critical metals may be formed where late-stage carbonatites and associated fluids interact with alkaline igneous rocks. A key question is whether these carbonatites are formed by liquid immiscibility from the host alkaline magmas, or whether they are introduced from other sources. A classic example of a mineral deposit formed in this way is at Ivigtut in Greenland, where late-stage F and CO2 rich fluids interacted with alkali granitic melts to form a cryolite (Na3AlF6) deposit, with associated metasomatism and REE mobilisation. Isotopic evidence indicates that these late-stage fluids may have been carbonatite-derived [2]. Our more recent work indicates that REE enrichment in many alkaline igneous complexes may be generated by a similar mechanism. In the alkaline igneous province of NW Scotland, late-stage metasomatism by CO2-rich fluids has generated metasomatised veins with TREO up to 2 wt% [3]. Similar features are observed in the Ditra? Alkaline Igneous complex in Romania, where REE mineralisation is represented by monazite- and carbonate-rich veins cutting syenitic host rocks [4]; and at the Kizilcaören REE deposit in Turkey. This talk will provide an overview of the formation of REE mineralisation in this type of magmatic-hydrothermal system and consider future research questions.
DS201709-1993
2017
Goodenough, K.M.Goodenough, K.M., Wall, F., Merriman, D.The Rare Earth Elements: demand, global resources and challenges for resourcing future generations.Natural Resources Research, in press available, 16p.Globalrare earths

Abstract: The rare earth elements (REE) have attracted much attention in recent years, being viewed as critical metals because of China’s domination of their supply chain. This is despite the fact that REE enrichments are known to exist in a wide range of settings, and have been the subject of much recent exploration. Although the REE are often referred to as a single group, in practice each individual element has a specific set of end-uses, and so demand varies between them. Future demand growth to 2026 is likely to be mainly linked to the use of NdFeB magnets, particularly in hybrid and electric vehicles and wind turbines, and in erbium-doped glass fiber for communications. Supply of lanthanum and cerium is forecast to exceed demand. There are several different types of natural (primary) REE resources, including those formed by high-temperature geological processes (carbonatites, alkaline rocks, vein and skarn deposits) and those formed by low-temperature processes (placers, laterites, bauxites and ion-adsorption clays). In this paper, we consider the balance of the individual REE in each deposit type and how that matches demand, and look at some of the issues associated with developing these deposits. This assessment and overview indicate that while each type of REE deposit has different advantages and disadvantages, light rare earth-enriched ion adsorption types appear to have the best match to future REE needs. Production of REE as by-products from, for example, bauxite or phosphate, is potentially the most rapid way to produce additional REE. There are still significant technical and economic challenges to be overcome to create substantial REE supply chains outside China.
DS201906-1273
2019
Goodenough, K.M.Beard, C.D., Goodenough, K.M., Deady, E.A.Deposit scale geomodels for REE and HFSE exploration in carbonatite and alkaline silicate magmatic systems.3rd International Critical Metals Meeting held Edinburgh, 1p.abstract p. 39.GlobalREE

Abstract: PDF link to presentation.
DS201909-2021
2019
Goodenough, K.M.Beard, C.D., Goodenough, K.M., Broom-Findlay, S., Borst, A.M., Roberts, N.M.W., Finch, A.A., Deady, E.A.Subducted sediments as a source of REE in mineralized post - collisional alkaline carbonatite systems.Goldschmidt2019, 1p. AbstractChinasubduction

Abstract: Many of the world's largest known REE deposits are associated with post-collisional alkaline-carbonatite magmatic complexes (e.g., the Minanning-Dechang belt, China). These systems are potassic to ultrapotassic in composition and contain LREE-dominated mineralisation associated with F and Ba-rich carbonatite breccias, carbonatite dykes and carbo-hydrothermal veins. They are typically emplaced through major shear zones during a period of 'relaxation' that postdates continental collision by up to 75 Ma. The subduction of sediment during continental collision is potentially a key control on the 'fertility' of the mantle source, and understanding the role of sediment is a crucial step towards better exploration models. However, the identification of sediment source components to alkaline systems has not been straightforward because their petrological complexity precludes traditional methods such as trace-element ratios and major-element modelling of crystal fractionation. We use a global database of Sr, Nd and Hf isotope compositions for alkaline and carbonatite systems, alongside geodynamic reconstructions to identify favourable source components for mineralisation and to provide direct information about the origin of the metals of interest. Subduction of shale and carbonate sequences is likely to introduce REE + HFSE and potentially mineralising ligands (F-, CO3 2-) into the mantle source for post-collisional alkaline systems; clastic sediments are poorer in these vital components. This research provides a framework through which the mineral exploration industry can identify tectonic environments that are predisposed to form REE mineralisation, providing regional-scale (100-1000 km) guidance especially for systems hidden beneath sedimentary cover.
DS1994-0497
1994
Goodfellow, W.D.Evans, N.J., Gregoire, D.C., Goodfellow, W.D., Miles, N., VeizerThe Cretaceous Tertiary fireball layer, ejecta layer and coal seam: platinum group elements (PGE) content and mineralogy of size fractionsUnknown, pp. 223-235Alberta, Italy, New Zealand, Denmark, Colorado, WyomingPlatinum Group Elements, K-T boundary
DS1995-0652
1995
Goodfellow, W.D.Goodfellow, W.D., Cecile, M.P., Leybourne, M.I.Geochemistry, petrogenesis and tectonic setting of lower Paleozoic alkalic and ultrapotassic rocks...Canadian Journal of Earth Sciences, Vol. 32, No. 8, Aug. pp. 1226-1254.Yukon, British ColumbiaBasanites, mineral chemistry, Deposit -Porter Puddle, Macmillan, Niddery, Mountain
DS200412-1187
2004
Goodfellow, W.D.Lydon, J.W., Goodfellow, W.D., Dube, B., Paradis, S., Sinclair, W.D., Corrivea, L., Gosselin, P.A preliminary overview of Canada's mineral resources. ( Diamond mentioned).Geological Survey of Canada, Open File 4668, 1 CD $ 20.00 ( pfd of poster, 20p. reptCanadaPoster - resources
DS200612-0475
2006
Goodfellow, W.D.Goodfellow, W.D.Mineral resources of Canada: a synthesis of major deposit types, district metallogeny, the evolution of geological provinces and exploration methods.Geological Association of Canada, 900p. 45 papers and DVDCanadaBook - mineral deposit knowledge
DS200712-0371
2007
Goodfellow, W.D.Goodfellow, W.D.Mineral deposits of Canada..... one section on kimberlite diamond deposits.Geological Association of Canada, Special Publication, No.5, $ 80.00 plus shipCanadaBook - advertisement
DS1995-1452
1995
Goodge, J.W.Peacock, S.M., Goodge, J.W.Eclogite facies metamorphism preserved in tectonic blocks from a lower crustal shear zone, TransantarcticLithos, Vol. 36, No. 1, Aug. 1, pp. 1-14.Antarcticametamorphism, Eclogite
DS2001-0396
2001
Goodge, J.W.Goodge, J.W., Fanning, C.M., Bennett, V.C.uranium-lead (U-Pb) evidence of1,7 Ga crustal tectonism during Nimrod Orogeny in the Transantarctic Mountains...Precambrian Research, Vol. 112, No. 3-4, Dec. 10, pp.261-88.AntarcticaProterozoic plate reconstructions, Tectonics
DS1990-0584
1990
Gooding, K.Gooding, K.RTZ faces suit on diamond moveIndiaqua, (Financial Times 3/10/89), No. 55 1990/1, p. 53IndonesiaNews item, RTZ -legal with Acorn
DS1998-0523
1998
Gooding, K.Gooding, K.De Beers' control in questionRaw Materials Report, Vol. 13, No. 1, pp. 4-5.GlobalEconomics - world trade, CSO
DS200612-0476
2005
Gooding, K.Gooding, K.A son of Africa...... profile of Kala MpingaMining Magazine, Nov. p. 42.AfricaProfile - Mpinga
DS1988-0260
1988
Goodings, C.R.Goodings, C.R.The Kapuskasing structure and its relationship to the Proterozoic movements in the Superior ProvinceMsc. Thesis University Of Waterloo, 99p. Ontario Geological Survey (OGS) LibraryOntarioMidcontinent, Kapuskasing structure
DS1992-0587
1992
Goodings, C.R.Goodings, C.R., Brookfield, M.E.Proterozoic transcurrent movements along the Kapuskasing lineament(Superior Province, Canada) and their relationship to surrounding structuresEarth Science Reviews, Vol. 32, pp. 147-185OntarioTectonics, Structure, Kapuskasing Rift - lineament
DS1981-0285
1981
Goodlad, S.W.Martin, A.K., Hartnady, C.J.H., Goodlad, S.W.Pre-drift Fit of the Natal Valley and the Falkland PlateauCape Town: Tech. Report Mar. Geosci. Unit, Geological Survey South, No. 12, PP. 30-44.South Africa, South AmericaTectonics
DS1995-1874
1995
Goodliffe, A.Taylor, B., Goodliffe, A., Martinez, F., Hey, R.Continental rifting and initial sea floor spreading in the Woodlark BasinNature, Vol. 374, No. 6522, April 6, p. 534-536.GlobalTectonics, Rifting
DS1995-1875
1995
Goodliffe, A.Taylor, B., Goodliffe, A., Martinez, F., Hey, R.Continental rifting and initial sea floor spreading in the Woodlark BasinNature, Vol. 374, April 6, pp. 534-537Papua New Guinea, Solomon IslandsTectonics, Rifting
DS201412-0306
2014
Goodrich, C.Goodrich, C., Bischoff, A., O'Brien, D.P.Asteroids: establishing asteroid-meteorite links.Elements, Vol. 10, 1, pp. 25-30.TechnologyAsteroids
DS202202-0193
2021
Goodrich, C.A.Goodrich, C.A., Nestola, F., Jakubek, R.S.Diamonds in ureilites: the never ending story.Cosmo Elements, 10.2138/gselements.17.4.292 2p. PdfCosmosUreilites
DS1985-0239
1985
Goodwin, A.M.Goodwin, A.M.Rooted Precambrian Ring Shields: Growth, Alignment, and Oscillation.American Journal of SCIENCE., Vol. 285, No. 6, JUNE, PP. 481-531.Canada, West Africa, Central AfricaGeotectonics, Comparison, Compositional Analyses, Belts
DS1991-0589
1991
Goodwin, A.M.Goodwin, A.M.Precambrian Geology -the dynamic evolution of the continental crustAcademic Press, 660p. approx. $ 200.00GlobalArchean crust, Tectonics
DS1991-0590
1991
Goodwin, A.M.Goodwin, A.M.Precambrian geology - the dynamic evolution of the continental crustAcademic Press, 666p. Approx. $ 200.00GlobalCrust -platforms, Craton, Models
DS1996-0543
1996
Goodwin, A.M.Goodwin, A.M.Principles of Precambrian geologyAcademic Press, 400pGlobal, CanadaBook -ad, Precambrian geoloy, plate tectonics, geodynamics
DS1994-0641
1994
Goodwin, C. H.Goodwin, C. H.Meridien network of banks in sub-Saharan Africa and their financingactivitiesMeridien Preprint, 11pAfricaEconomics
DS1989-0527
1989
Goodwin, E.B.Goodwin, E.B., Thompson, G.A., Okaya, D.A.Seismic identification of basement reflectors: the Bagdad reflection sequence in the Basin and Range Province- Colorado Plateau transition zone, ArizonaTectonics, Vol. 8, No. 4, August pp. 821-832Colorado PlateauTectonics
DS1986-0212
1986
Goodwin, J.H.Eidel, I.J., Frost, J.K., Goodwin, J.H.Hole into basement to explore earth's crustGeotimes, Vol. 31, No. 9, pp. 11-13GlobalTectonics
DS1991-0591
1991
Goodwin, P.B.Goodwin, P.B., et al.Evaluation and updating of offshore base maps using SPOT satellite image sand GPS control, West AfricaProceedings of the Eighth Thematic Conference on Geologic Remote, Vol. I, pp. 253-264West AfricaRemote sensing, Offshore maps
DS1995-0492
1995
Goodwin, P.B.Ellis, J.M., Goodwin, P.B.Using satellite imagery, CAD and GPS to develop environmental and engineering baselineEarth Observation Magazine, October pp. 16-18GlobalRemote sensing, Brief overview
DS1993-0345
1993
Goody, A.Dey, S.C., Kennett, B.L.N., Bowman, J.R., Goody, A.Variations in upper mantle structure under northern AustraliaGeophysical Journal International, Vol. 114, pp. 304-310AustraliaGeophysics - seismics
DS201412-0460
2014
Goodyear, A.C.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
Goodyear, A.C.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
DS1860-0144
1871
Goodyear, W.A.Goodyear, W.A.The Gravel Hills of PlacervilleMining and Scientific Press, Vol. 23, Nov. 25TH. DEC 2ND. P. 329, P. 342.United States, CaliforniaDiamond Occurrence
DS1860-0207
1873
Goodyear, W.A.Goodyear, W.A.Diamonds in El Dorado County, California. In: Fourth Report on Mineral Resources of the States and Territories West of The Mississippi. R.w. Raymond.42nd. Congress, 2nd. Session, House Executive Document., No. 211, P. 29.United States, CaliforniaDiamond Occurrence
DS1993-0560
1993
Goodz, M.D.Goodz, M.D., Frith, R.A.The real sample: variations between dust, chip and core drillingAusIMM International Mining Conference Kalgoorlie WA., pp. 19-23AustraliaSampling - general interest, Gold and sulphides
DS1910-0186
1911
Goold, M.N.Goold, M.N.The Treasure House. Spin drift and Sand DriftLondon:, PP. 144-151.South AfricaDiamonds, Kimberley
DS200912-0258
2009
Goosens, P.J.Goosens, P.J.Mineral potential of the Democratic Republic of Congo: a geologic scandal?SEG Newsletter, No. 77, April pp. 1, 13-18.Africa, Democratic Republic of Congop. 15 diamonds
DS2000-0349
2000
Goossens, P.J.Goossens, P.J.Mining in Africa: pros and cons... special reference to West AfricaEngineering and Mining Journal, Vol. 201, No. 9, Sept. p.45-95.West AfricaMining - overview
DS1994-0642
1994
Goovaerts, P.Goovaerts, P.On a controversial method for modeling a coregionalizationMathematical Geology, Vol. 26, No. 2, pp. 197-204GlobalGeostatistics, Variograms
DS1997-0427
1997
Goovaerts, P.Goovaerts, P.Geostatistics for natural resources evaluationOxford, 500p. $ 107.00GlobalBook - table of contents, Geostatistics
DS1994-0042
1994
Goowell, G.R.Ambroziak, R.A., Cook, C.A., Goowell, G.R., Dargusch, T.Computer mapping at your desk .. that really works.. short course aboutcreating digital maps on a PC.Geological Society of America (GSA) Short Course, 100p. approx. $ 15.00GlobalBook -table of contents, Computer mapping programs
DS1970-0247
1971
Gopal, V.Borodin, L.S., Gopal, V., Moralev, V.M., Suramanian, V., PonikarPrecambrian Carbonatites of Tamil Nadu, South IndiaGeological Society INDIA Journal, Vol. 12, No. 2, PP. 101-112.India, Tamil NaduPetrography, Analyses
DS1987-0648
1987
Gopalakrishna, C.V.et al.Sarma, S.V.S., Harinarayana, T., Gopalakrishna, C.V.et al.Tellurics in the detection and delineation of lineament features In kimberlite areas, an experimental approachIntegrated Geophysical Exploration for Mineral Deposits, Baroda, Vol. 13, p. A30. (Abstract)IndiaGeophysics -Tellurics, Kimberlite
DS202007-1163
2019
Gopalakrishna, G.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.
DS1993-0862
1993
GopalanKumar, A., Padma Kumari, V.M., Dayal, A.M., Murthy, D.S.N., Gopalanrubidium-strontium (Rb-Sr) ages of Proterozoic kimberlites of India: evidence for contemporaneous emplacementPrecambrian Research, Vol. 62, No. 3, June pp. 227-238IndiaKimberlites, Geochronology
DS1989-1463
1989
Gopalan, K.Subba Rao, T.V., Bhaskar Rao, Y.J., Sivaraman, T.V., Gopalan, K.rubidium-strontium (Rb-Sr) age and petrology of the Elchuru Alkaline Complex implications to alkaline magmatism in the eastern Ghat mobile beltGeological Society of India, Memoir, Editor C. LeelanandaM., No. 15, pp. 207-224IndiaAlkaline rocks, Geochronology
DS1992-0902
1992
Gopalan, K.Kumar, A., Srinivansan, R., Gopalan, K., Patil, D.J.A reappraisal of an Archean carbonatite of Nellor schist belt, SouthIndiaJournal Geological Society of India, Vol. 40, August pp. 169-174IndiaCarbonatite, Geochemistry
DS1992-0903
1992
Gopalan, K.Kumar, A., Srinivasan, R., Gopalan, K., Patil, D.J.A reappraisal of an Archean carbonatite of Neollore schist belt, KarnatakaJournal of Geological Society India, Vol. 40, No. 2, August pp. 169-175IndiaCarbonatite
DS1993-1096
1993
Gopalan, K.Murari, R., Krishnam, P., Tikhonen, P.I., Gopalan, K.Magnesian ilmenites in picrite basalts from Siberian and Deccan traps-additional mineralogical evidence for primary melt compositions.Mineralogical Magazine, Vol. 57, No. 389, December pp. 733-735.Russia, IndiaPicrite basalts
DS1995-1037
1995
Gopalan, K.Kumar, A., Gopalan, K., Padmakumari, V.M., Kornilova et al.Precise Rubidium-Strontium ages of Siberian kimberlitesProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 307.Russia, Yakutia, SiberiaGeochronology, Deposit - Alakit, Malo-Botuobia, Kharamay
DS1997-0641
1997
Gopalan, K.Kumar, A., Charan, S.N., Gopalan, K., Macdougall, J.D.Isotope evidence for a long lived source for Proterozoic carbonatites from South India.Geological Association of Canada (GAC) Abstracts, India, southCarbonatite, Proterozoic, geochronology
DS1998-0817
1998
Gopalan, K.Kumar, A., Charan, N., Gopalan, K., Macdougall, J.D.A long lived enriched mantle source for two Proterozoic carbonatite complexes from Tamil Nadu, southern India.Geochimica et Cosmochimica Acta, Vol. 62, No. 3, Feb. pp. 515-523.IndiaCarbonatite, Hogenakal, Sevathur, geochronology
DS1999-0257
1999
Gopalan, K.Gopalan, K., Kumar, A.Contrasting isotopic mantle sources for Proterozoic lamproites And kimberlites from the Cuddapah Basin. #2Journal of Geological Society India, Vol. 53, No. 3, Mar. pp. 373-4.IndiaDharwar Craton, Geochronology
DS1999-0258
1999
Gopalan, K.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
DS2000-0534
2000
Gopalan, K.Krishnamurthy, P., Gopalan, K., MacDougall, J.D.Olivine compositions in picrite basalts and the Deccan volcanic cycleJournal of Petrology, Vol. 41, No. 7, July, pp. 1057-70.IndiaPicrites
DS200412-1067
2001
Gopalan, K.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
DS200512-0585
2005
Gopalan, K.Kumar, A., Gopalan, K.Comments on: petrogenesis of Proterozoic lamproites and kimberlites from Cuddapah Basin and Dharwar Craton, southern India.Journal of Petrology, Vol. 46, 6, June pp. 1077-1079.IndiaLamproite, kimberlites
DS200712-0372
2007
Gopalan, K.Gopalan, K.Helium isotopic memories of episodic mantle melting and crustal growth.Current Science, Vol. 93, 1, July 10, pp. 13-14.MantleMelting
DS1992-0588
1992
Gopalen, K.Gopalen, K., Anil KumarPrecise rubidium-strontium (Rb-Sr) ages of South Indian kimberlites and Central IndianlamproitesInternational Roundtable Conference on Diamond Exploration and Mining, held, p. 98. abstract onlyIndiaGeochronology, isotopes, Kimberlites
DS1994-1264
1994
Gopalen, K.Natarajan, M., Bhaskar Rao, B., Parthasarathy, R., Kumar, A., Gopalen, K.2.0 Ga old pyroxenite-carbonatite complex of Hogenakai, Tamil Nadu, SouthIndia.Precambrian Research, Vol. 65, No. 1-4, January pp. 167-182.IndiaCarbonatite
DS2002-0105
2002
Gopei, C.Barrat, J.A., Jambon, A., Bohn, M., Gillet, P., Sautter, V., Gopei, C., Lesourd, M.Petrology and chemistry of the picritic shergottite north west AfricaGeochimica et Cosmochimica Acta, Vol.66, 19, pp.3505-18.West AfricaPicrites
DS200812-0020
2008
Gopel, C.Allegre, C.J., Manhes, G., Gopel, C.The major differentiation of the Earth at - 4.45 Ga.Earth and Planetary Science Letters, Vol. 267, 1-2, pp.386-398.MantlePetrology
DS1860-0011
1863
GoppertGoppertDie Diamanten und Ihre EntstehungSchles. Ges. Vat. Kult. Jahrb., GlobalDiamond Genesis, Gemology
DS201212-0752
2012
Gora, M.P.Vasilev, Yu.R.,Gora, M.P.The origin of dunites and olivinites in the alkali-ultrabasic intrusive complexes of the Siberian craton.Doklady Earth Sciences, Vol. 442, 1, pp.36-39.Russia, SiberiaAlkalic
DS201412-0942
2014
Gora, M.P.Vasilev, Yu.R., Gora, M.P.Meimechite-picrite associations in Siberia, Primorye, and Kamchatka ( comparitive analysis and petrogenesis).Russian Geology and Geophysics, Vol. 55, 8, pp. 959-970.RussiaMeimechite
DS201412-0943
2014
Gora, M.P.Vasilev, Yu.R., Gora, M.P.Meimechite-picrite associations in Siberia, Primorye and Kamchatka ( compartive analysis and petrogenesis).Russian Geology and Geophysics, Vol 55, pp. 959-970.Russia, SiberiaMeimechite, picrite
DS201608-1448
2016
Gora, M.P.Vasilev, Yu.R., Gora, M.P.Nature of voluminous meimechite picrite associations in Siberia and other regions.Doklady Earth Sciences, Vol. 468, 1, pp. 469-472.RussiaMeimechite, picrite

Abstract: Analysis of petrochemical and geochemical information of the same levels, which characterize rocks and primary melt inclusions in olivines of heterochronic meimechite-picrite associations in Siberia (Maimecha-Kotui province), Primorye (Sikhote-Alin), and Kamchatka demonstrated that, besides the similar appearance and identical structural patterns, they are considerably discrepant in the concentration and distribution of incompatible and rare earth elements. Those differences are also observed for the compositions and evolutionary trends of parental high-temperature magnesium-rich melts. This, in turn, was assumed to be a consequence of a variable degree of melting of the mantle protoliths in the mentioned regions, which is supported by geochemical modeling.
DS201707-1379
2017
Gora, M.P.Vasilev, Yu.R., Gora, M.P., Kuzmin, D.V.Petrology of foiditic and meymechitic volcanism in the Maimecha - Kotui province ( Polar Siberia).Russian Geology and Geophysics, Vol. 58, pp. 659-673.Russia, Siberiaalkaline - Maimecha

Abstract: Comparative analysis of ultramafic meymechites of the Maimecha Suite and alkaline volcanics of the Ary-Dzhang Suite (foidites (nephelinites, analcimites, limburgites, etc.) and melilitites) has shown their consanguinity, which indicates their relationship with the same magmatic system periodically producing large amounts of alkaline ultramafic melts. We have studied the petrogeochemical and mineralogical compositions of rocks and melt inclusions in the hosted olivines. The rocks of the Maimecha and Ary-Dzhang Suite differ considerably in MgO content, which is well explained by the accumulation of olivine. The inclusions in olivines from the meymechites and the rocks of the Ary-Dzhang Suite correspond in composition to foidites. The trace and rare-earth element patterns are similar both in the foidites and meymechites and in the melt inclusions: They show negative anomalies of Rb and K and positive anomalies of Nb and Ta. The ratios of indicator elements (Nb/Ta, Ba/La, Ta/La, etc.) in the rocks of the Maimecha and Ary-Dzhang Suite are constant and almost independent of their Mg# values. The La/Yb ratio in the foidites is significantly higher than that in the meymechites and in the melt inclusions from their olivines, which indicates that the rocks of the Ary-Dzhang Suite resulted from the fractionation of highly magnesian alkaline picritoid melt.
DS201804-0750
2018
Gora, M.P.Vasilev, Yu.R., Gora, M.P., Kuzmin, D.V.Foidite and meimechite lavas of Polar Siberia ( some questions of petrogenesis.Doklady Earth Sciences, Vol. 478, 1, pp. 103-107.Russia, Siberiapicrites

Abstract: For the Permian-Triassic foidite and meimechite lavas of Polar Siberia, both the whole-rock petrochemistry and geochemistry and that of melt inclusions in olivine phenocrysts from the same rocks have been demonstrated to be similar. In addition, their isotope characteristics imply the possibility of their generation from an abyssal parental melt compositionally resembling a high-Mg alkaline picrite.
DS1996-0149
1996
GoratschevBogdanova, S.V., Pashkevich, Goratschev, OrlyukRiphean rifting and major Paleoproterozoic crustal boundaries in the basement of the East European CratonTectonophysics, Vol. 268, pp.1-21.Baltic States, Europe, UralsTectonics, Geophysics - MGSAT.
DS2000-0350
2000
Gorayeb, P.S.S.Gorayeb, P.S.S., Moura, C.A.V., Gaudette, H.E., AbreuTransamazonic evolution of Sao Luis Craton and northwest Ceara Brasil - and its coerrelation with west Africa.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, West AfricaCraton - tectonics, Magmatism
DS1985-0518
1985
Gorbache, S.E.Pavlov, D.I., Ilupin, I.P., Gorbache, S.E.Buried Brines of the Siberian Platform As a Possible Fact orin Transformation of Primary Kimberlitic Composition.Izves. Akad. Nauk Sssr., RussiaBlank
DS1993-1818
1993
Gorbachev, N.Zharikov, V., Gorbachev, N., Lightfoot, P., Khodorevsky, L.Temperature and pressure dependence of partitioning of the rare earth elements (REE) and Ybetween fluid and lamproitic melt.Terra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 57.GlobalExperimental petrology, Lamproite
DS1990-0585
1990
Gorbachev, N.S.Gorbachev, N.S.Fluid magma interaction and the origin of kimberlitesInternational Geology Review, Vol. 32, No. 8, August, pp. 820-821RussiaKimberlites, Magma genesis
DS2000-0351
2000
Gorbachev, N.S.Gorbachev, N.S.Supercritical state in the hydrous mantle: evidence from experimental study of fluid bearing peridotiteDoklady Academy of Sciences, Vol. 370, No. 1, Jan-Feb pp. 147-49.MantlePeridotite
DS201510-1803
2015
Gorbachev, N.S.Shapovalov, Yu.B., Gorbachev, N.S., Kostyuk, A.V., Sultanov, D.M.Geochemical features of carbonatites of the Fennoscandian shield.Doklady Earth Sciences, Vol. 463, 2, pp. 833-838.Europe, Norway, Russia, Kola Peninsula, KareliaCarbonatite

Abstract: The petrochemistry of carbonatites of three formation types were studied: (1) ultrahigh-pressure garnet-containing carbonatites (UHPC) of the Caledonian sheet (Tromsö, Norway); (2) rocks of the carbonatite-lkaline-ultrabasic Kovdor massif (the Kola Peninsula); and (3) rocks of the carbonatite-alkaline-gabbroid Tikshozero massif (north of Karelia). The samples of carbonatites were examined and tested with a microprobe; the microelements were determined using the ICP-MS technique at the Institute of Microelectronics Technology and High Purity Materials (Chernogolovka). The carbonatites of the Kovdor and Tikshozero massifs are characterized by similar negative REE trends, with a degree of REE enrichment of the Tikshozero carbonatites. The UHPC from Tromsö are different from those of the Kovdor and Tikshozero massifs in the negative trend along with lower concentrations of light REEs. The Tromsö UHPC are similar to the carbonatites of the Kovdor and Tikshozero massifs in the trend and concentrations of heavy REEs. The carbonatites of the Fennoscandian shield of various formation times and types are characterized by the geochemical similarity to those in different regions of the world with the sources associated to mantle plumes. This similarity might be caused by the formation of the mantle carbonated magmas of carbonatite-containing igneous complexes from a mantle source enriched under either mantle metasomatism or plume-lithosphere interaction, with similar mechanisms of formation. The appearance of the formations as such within a wide time interval points to the long-term occurrence of a superplume at the Fennoscandian shield and to permanent activation of the related processes of magma formation.
DS201512-1921
2015
Gorbachev, N.S.Gorbachev, N.S., Kostyuk, A.V., Shapovalov, Yu.B.Experimental study of the basalt-carbonate-H2O system at 4 Gpa and 1100-1300C: origin of carbonatitic and high-K silicate magmas.Doklady Earth Sciences, Vol. 464, 2, pp. 1018-1022.TechnologyCarbonatite
DS201706-1074
2017
Gorbachev, N.S.Gorbachev, N.S., Shapovalov, Yu.B., Kostyuk, A.V.Experimental study of the apatite carbonate H2O system at P=0.5 Gpa and T=1200C efficiency of fluid transport in carbonatite.Doklady Earth Sciences, Vol. 473, 1, pp. 350-353.carbonatite

Abstract: This study presents geochemical data on organic-rich rock samples collected from Riphean—Lower Paleozoic strata (potential source rocks) of the southern Siberian Platform and compositional data on hydrocarbon biomarkers (steranes, terpanes, n-alkanes, 12- and 13-methylalkanes, isoprenanes) and diamondoid hyrocarbons from core samples collected from the Kulindinskaya-1 well, which was drilled by RN-Exploration in 2012 within the Katanga saddle.
DS202109-1476
2021
Gorbachev, N.S.Kostyuk, A.V., Gorbachev, N.S., Nekrasov, A.N.Petrogenesis of garnet-bearing carbonatite in the Tromso Nappe, Norway.Geochemistry International, Vol. 59, 8, pp. 801-812. pdfEurope, Norwaydeposit - Tromso Nappe

Abstract: The paper presents data on phase relations in garnet-bearing carbonatite from the Tromsø Nappe, Norway. The carbonatite matrix consists of calcite-dolomite carbonate with three generations of garnet inclusions (up to 15-20%). The relics of the primary garnets (Grt1) are depleted (<10-2 wt %) in the rare earth elements (REE). The garnet of the second and third generations (Grt2-3) is anomalously enriched (up to 10-15 wt %) in the light REE (LREE), and the carbonates are depleted in these elements. The distribution of REE between the garnet and carbonate indicates the absence of equilibrium. The melting of the carbonatite at T = 950-1400°C, P = 4.0 GPa showed that the “dry” solidus temperature is 1150°C, and the liquidus temperature is >1300°C. In the experiment with H2O + CO2 fluid, the solidus and liquidus temperatures are ?950 and 1250°C, respectively. The subsolidus association is calcite, garnet, clinopyroxene, biotite, and accessory minerals: apatite, ilmenite, rutile, and titanite. The garnet and carbonatite melt occur in reaction relationships, as is evident from the garnet zoning with a decrease in the FeO and increase in the MgO, CaO, TiO2, and LREE concentrations. The geological setting, phase relationships, and experimental data indicate that the garnet-bearing carbonatites in the Tromsø area were formed in relation to the carbonatization and melting of upper mantle material at high pressures during the collision of the Baltica and Laurentia plates in the course of the Caledonian orogenesis, with subsequent intrusion and crystallization of silicate-carbonate magmas.
DS1990-0507
1990
Gorbachev, V.V.Galimov, E.M., Kuznetsov, V.P., Maltsev, K.A., Gorbachev, V.V.Isotopic composition of diamonds bearing the inclusions of diamond.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 7, July pp. 1033-1040RussiaDiamond inclusions, Geochronology
DS1990-0896
1990
Gorbachev, V.V.Kuznetsova, V.P., Maltsev, K.A., Gorbachev, V.V., Zezin, R.B.Isotopic composition of diamonds bearing inlclusions of diamonds.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 7, July pp. 1033-1039RussiaDiamond inclusions, Diamonds
DS1991-0528
1991
Gorbachev, V.V.Galimov, E.M., Kuznetsova, V.P., Maltsev, K.A., Gorbachev, V.V.Isotope composition of diamonds containing diamond inclusionsGeochemistry International, Vol. 28, No. 1, pp. 115-121RussiaGeochronology, Diamond inclusions
DS1985-0519
1985
Gorbacheva, S.A.Pavlov, D.I., Ilupin, I.P., Gorbacheva, S.A.Buried brines of the Siberian platform a possible factor of the transformation of the original composition of kimberlites.(Russian)Izv. Akad. Nauk SSR Ser. Geol., (Russian), No. 3, pp. 44-53RussiaKimberlite, Geochemistry
DS1985-0520
1985
Gorbacheva, S.A.Pavlov, D.I., Ilupin, I.P., Gorbacheva, S.A.Connate brines of the Siberian platforms as a factor in the alteration ofkimberliteInternational Geology Review, Vol. 27, No. 5, May pp. 600-609RussiaMirnyy, Udachnyy, Halite, Mineral Chemistry
DS200912-0259
2009
Gorbatikov, A.V.Gorbatikov, A.V., Larin, N.V., Moiseev, E.I., Belyashov, A.V.The microseismic sounding method: application for the study of the buried diatreme structure.Doklady Earth Sciences, Vol. 428, 1, pp. 1222-1226.TechnologyGeophysics - seismics
DS200412-0982
2004
Gorbatov, A.Kennett, B.L., Gorbatov, A.Seismic heterogeneity in the mantle strong shear wave signature of slabs from joint tomography.Physics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 87-100.MantleGeophysics - seismic
DS2001-0195
2001
GorbatschevClaesson, S., Bogdanova, S.V., Bibikova, GorbatschevIsotopic evidence for Paleoproterozoic accretion in the basement of the East European Craton.Tectonophysics, Vol. 339, No. 1-2, pp. 1-18.EuropeGeochronology, Craton
DS1993-0561
1993
Gorbatschev, R.Gorbatschev, R.The Baltic shield... special volumePrecambrian Research, pp. 1-450Sweden, Finland, NorwayGeochronology, Petrology
DS1993-0562
1993
Gorbatschev, R.Gorbatschev, R., Bogdanova, S.Frontiers in the Baltic ShieldPrecambrian Research, Vol. 64, pp. 3-21.Baltic ShieldTectonics - East European Platform
DS2001-0707
2001
Gorbatschev, R.Lund, C.E., Gorbatschev, R., Smirnov, A.A seismic model of the Precambrian crust along the coast of southeastern Sweden: the coast profile wideTectonophysics, Vol. 339, No. 1-2, pp. 93-111.SwedenFennolora revisited, Wide angle airgun experiment
DS200712-0088
2006
Gorbatschev, R.Bogdanova, S., Gorbatschev, R., Grad, M., Janik, T., Guterch, A., Kozlovskaya, E., Motuza, G., SkridaiteEUROBRIDGE: new insight into the geodynamic evolution of the East European Craton.Geological Society of London Memoir, No. 32, pp. 599-626.EuropeCraton
DS201907-1546
2019
Gorce, J.S.Gorce, J.S., Caddick, M.J., Bodnar, R.J.Thermodynamic contraints on carbonate stability and carbon volatility during subduction.Earth and Planetary Science Letters, Vol. 519, pp. 213-222.Mantlecarbon cycle

Abstract: The breakdown of carbonate minerals at high pressure is frequently cited as an important mechanism that leads to carbon release from subducted rocks. However, carbonate minerals in the subducting slab are predicted to be stable to depths that are greater than arc-generating magma depths of approximately 150 km, implying that breakdown of carbonate phases in dehydrated MORB may not be a major contributor to arc volcano carbon budgets. To account for this discrepancy, previous studies have suggested that addition of H2O-rich fluids promotes the breakdown of carbonate-rich lithologies, thus generating volatile C species that could be incorporated into arc magmas. Here, we explore the feasibility of H2O-mediated decarbonation with a simple thermodynamic model. We calculate equilibrium mineral assemblages and accompanying fluid H2O/CO2 ratios for typical subducted lithologies, assuming a range of subduction zone geotherms, and explore the implications of addition of external fluids that are generated from deserpentinization of ultramafic lithologies at various stages. Results suggest that the liberation of C along volcanic arcs is facilitated by either the breakdown of carbonate minerals due to thermodynamically favorable conditions in hotter subduction systems, or by the breakdown of carbonate minerals during periods of higher fluid productivity associated with deserpentinization at appropriate depths along colder subduction geotherms. A comparison of C fluxes measured at volcanic arcs shows that colder subduction zones generate higher C fluxes, implying that the depth at which deserpentinization reactions occur strongly controls the availability of aqueous fluids for slab decarbonation, and that fluid availability represents the dominant control on carbon volatility during subduction.
DS1860-0382
1882
Gorceix, H.Gorceix, H.Brazilian Diamonds and their OriginPopular Science Monthly, Vol. 21, PP. 610-620.South America, Brazil, Bahia, Goias, Mato Grosso, Parana, Minas GeraisHistory, Genesis, Distribution, Mining Methods, Geomorphology
DS202202-0228
2022
Gorczk, W.Zhao, L., Tyler, I.M., Gorczk, W., Murdie, R.E., Gessner, K., Lu, Y., Smithies, H., Lia, T., Yang, J., Zhan, A., Wan, B., Sun, B., Yuan, H.Seismic evidence of two cryptic sutures in northwestern Australia: implications for the style of subduction during the Paleoproterozoic assembly of Columbia.Earth and planetary Science Letters, Vol. 579, 117343, 11p. PdfAustraliageophysics- seismics

Abstract: Plate tectonics, including rifting, subduction, and collision processes, was likely to have been different in the past due to the secular cooling of the Earth. The northeastern part of the West Australian Craton (WAC) has a complex Archean and Paleoproterozoic tectonic history; therefore, it provides an opportunity to study how subduction and collision processes evolved during the emergence of plate tectonics, particularly regarding the assembly of Earth's first supercontinent, Columbia. Because the northeastern boundary of the WAC and the southwestern boundary of the North Australian Craton (NAC) are covered by the Phanerozoic Canning Basin, the regional tectonic evolution has remained enigmatic, including how many tectonic elements were assembled and what may have driven rifting and subsequent collision events. Here, we use new passive-source seismic modeling to identify a seismically distinct segment of the lithosphere, the Percival Lakes Province, which lies east of the Pilbara Craton and is separated by two previously unknown southeast-trending lithosphere scale Paleoproterozoic sutures. We interpret that the northeastern suture, separates the Percival Lakes Province from the NAC, records the amalgamation of the WAC with the NAC. The southwestern suture separates the PLP from the reworked northeastern margin of the Pilbara Craton, including the East Pilbara Terrane and the Rudall Province. A significant upper mantle dipping structure was identified in the southwestern suture, and we interpret it to be a relic of subduction that records a previously unknown Paleoproterozoic collision that pre-dated the amalgamation of the WAC and NAC. By comparing our findings with previously documented dipping features, we show that the Paleoproterozoic collisions are seismically distinguishable from their Phanerozoic counterparts.
DS200612-0451
2006
Gorczyk, W.Gerya, T.V., Connolly, J.A.D., Yuen, D.A., Gorczyk, W., Capel, A.M.Seismic implications of mantle wedge plumes.Physics of the Earth and Planetary Interiors, Vol. 156, 1-2, June 16, pp. 59-74.MantleGeophysics - seismic, subduction, tomography, melting
DS200612-0452
2006
Gorczyk, W.Gerya, T.V., Connolly, J.A.D., Yuen, D.A., Gorczyk, W., Capel, A.M.Seismic implications of mantle wedge plumes.Physics of the Earth and Planetary Interiors, Vol. 156, 1-2, pp. 59-74.MantleSubduction zones, tomography, melting
DS200712-0373
2007
Gorczyk, W.Gorczyk, W., Gerya, T.V., Connolly, J.A.D., Yuen, D.A.Growth and mixing dynamics of mantle wedge plumes.Geology, Vol. 35, 7, pp. 587-590.MantleSubduction
DS201312-0321
2013
Gorczyk, W.Gorczyk, W., Hobbs, B., Gessner, K., Gerya, T.Intracratonic geodynamics.Gondwana Research, Vol. 24, 3, pp. 838-848.MantleCraton, compression, extension
DS201312-0323
2013
Gorczyk, W.Gorczyk, W., Vogt, K.Tectonics and melting in intra-continental settings.Gondwana Research, in press availableMantleTectonics
DS201609-1719
2016
Gorczyk, W.Gonzales, C.M., Gorczyk, W., Gerya, T.V.Decarbonation of subducting slabs: insight from petrological-thermomechanical modeling.Gondwana Research, Vol. 36, pp. 314-332.MantleSubduction

Abstract: Subduction of heterogeneous lithologies (sediments and altered basalts) carries a mixture of volatile components (H2O ± CO2) into the mantle, which are later mobilized during episodes of devolatilization and flux melting. Several petrologic and thermodynamic studies investigated CO2 decarbonation to better understand carbon cycling at convergent margins. A paradox arose when investigations showed little to no decarbonation along present day subduction geotherms at subarc depths despite field based observations. Sediment diapirism is invoked as one of several methods for carbon transfer from the subducting slab. We employ high-resolution 2D petrological-thermomechanical modeling to elucidate the role subduction dynamics has with respect to slab decarbonation and the sediment diapirism hypothesis. Our thermodynamic database is modified to account for H2O-CO2 binary fluids via the following lithologies: GLOSS average sediments (H2O: 7.29 wt.% & CO2: 3.01 wt.%), carbonated altered basalts (H2O: 2.63 wt.% & CO2: 2.90 wt.%), and carbonated peridotites (H2O: 1.98 wt.% & CO2: 1.50 wt.%). We include a CO2 solubility P-x[H2O wt.%] parameterization for sediment melts. We parameterize our model by varying two components: slab age (20, 40, 60, 80 Ma) and convergence velocity (1, 2, 3, 4, 5, 6 cm year? 1). 59 numerical models were run and show excellent agreement with the original code base. Three geodynamic regimes showed significant decarbonation. 1) Sedimentary diapirism acts as an efficient physical mechanism for CO2 removal from the slab as it advects into the hotter mantle wedge. 2) If subduction rates are slow, frictional coupling between the subducting and overriding plate occurs. Mafic crust is mechanically incorporated into a section of the lower crust and undergoes decarbonation. 3) During extension and slab rollback, interaction between hot asthenosphere and sediments at shallow depths result in a small window (~ 12.5 Ma) of high integrated CO2 fluxes (205 kg m? 3 Ma? 1).
DS201707-1331
2017
Gorczyk, W.Gorczyk, W., Mole, D.R., Barnes, S.J.Plume lithosphere interaction at craton margins throughout Earth history.Tectonophysics, in press availableMantlecraton - plumes

Abstract: Intraplate continental magmatism represents a fundamental mechanism in Earth's magmatic, thermal, chemical and environmental evolution. It is a process intimately linked with crustal development, large-igneous provinces, metallogeny and major global environmental catastrophes. As a result, understanding the interactions of continental magmas through time is vital in understanding their effect on the planet. The interaction of mantle plumes with the lithosphere has been shown to significantly affect the location and form of continental magmatism, but only at modern mantle conditions. In this study, we perform numerical modelling for Late Archean (1600 °C), Paleoproterozoic (1550 °C), Meso-Neoproteroic (1500 °C) and Phanerozoic (1450 °C) mantle potential temperatures (Tp) to assess the time-space magmatic effects of ambient-mantle- and plume- lithosphere interaction over Earth's thermal history. Within these experiments, we impinge a mantle plume, with a time-appropriate Tp, onto a ‘step-like’ lithosphere, to evaluate the effect of craton margins on continental magmatism through time. The results of this modelling demonstrate that lithospheric architecture controls the volume and location of continental magmatism throughout Earth history, irrespective of ambient mantle or plume Tp. In all plume models, mantle starting plumes (diameter 300 km) impinge on the base of the lithosphere, and spread laterally over > 1600 km, flowing into the shallowest mantle, and producing the highest volume magmas. In ambient-mantle only models, Archean and Paleoproterozoic Tp values yield significant sub-lithospheric melt volumes, resulting in ‘passive’ geodynamic emplacement of basaltic magmatic provinces, whereas no melts are extracted at > 100 km for Meso-Neoproterozoic and Phanerozoic Tp. This indicates a major transition in non-subduction related continental magmatism from plume and ambient mantle to a plume-dominated source around the Mesoproterozoic. While the experiments presented here show the variation in plume-lithosphere interaction through time, the consistency in melt localisation indicates the lithosphere has been a first-order control on continental magmatism since its establishment in the Mesoarchean.
DS201710-2228
2017
Gorczyk, W.Gonzalez, C.M., Gorczyk, W.Decarbonation in an intracratonic setting: insight from petrological- thermomechanical modeling.Journal of Geophysical Research: Solid Earth, Vol. 122, 8, pp. 5992-6013.Mantlegeothermometry

Abstract: Cratons form the stable core roots of the continental crust. Despite long-term stability, cratons have failed in the past. Cratonic destruction (e.g., North Atlantic Craton) due to chemical rejuvenation at the base of the lithosphere remains poorly constrained numerically. We use 2-D petrological-thermomechanical models to assess cratonic rifting characteristics and mantle CO2 degassing in the presence of a carbonated subcontinental lithospheric mantle (SCLM). We test two tectonothermal SCLM compositions: Archon (depleted) and Tecton (fertilized) using 2 CO2 wt % in the bulk composition to represent a metasomatized SCLM. We parameterize cratonic breakup via extensional duration (7-12 Ma; full breakup), tectonothermal age, TMoho (300-600°C), and crustal rheology. The two compositions with metasomatized SCLMs share similar rifting features and decarbonation trends during initial extension. However, we show long-term (>67 Ma) stability differences due to lithospheric density contrasts between SCLM compositions. The Tecton model shows convective removal and thinning of the metasomatized SCLM during failed rifting. The Archon composition remained stable, highlighting the primary role for SCLM density even when metasomatized at its base. In the short-term, three failed rifting characteristics emerge: failed rifting without decarbonation, failed rifting with decarbonation, and semifailed rifting with dry asthenospheric melting and decarbonation. Decarbonation trends were greatest in the failed rifts, reaching peak fluxes of 94 × 104 kg m?3. Increased TMoho did not alter the effects of rifting or decarbonation. Lastly, we show mantle regions where decarbonation, mantle melting in the presence of carbonate, and preservation of carbonated mantle occur during rifting.
DS201801-0019
2017
Gorczyk, W.Gorczyk, W., Mole, D.R., Barnes, S.J.Plume lithosphere interaction at craton margins throughout Earth history.Tectonophysics, in press available, 17p.Mantleplume

Abstract: Intraplate continental magmatism represents a fundamental mechanism in Earth's magmatic, thermal, chemical and environmental evolution. It is a process intimately linked with crustal development, large-igneous provinces, metallogeny and major global environmental catastrophes. As a result, understanding the interactions of continental magmas through time is vital in understanding their effect on the planet. The interaction of mantle plumes with the lithosphere has been shown to significantly affect the location and form of continental magmatism, but only at modern mantle conditions. In this study, we perform numerical modelling for Late Archean (1600 °C), Paleoproterozoic (1550 °C), Meso-Neoproteroic (1500 °C) and Phanerozoic (1450 °C) mantle potential temperatures (Tp) to assess the time-space magmatic effects of ambient-mantle- and plume- lithosphere interaction over Earth's thermal history. Within these experiments, we impinge a mantle plume, with a time-appropriate Tp, onto a ‘step-like’ lithosphere, to evaluate the effect of craton margins on continental magmatism through time. The results of this modelling demonstrate that lithospheric architecture controls the volume and location of continental magmatism throughout Earth history, irrespective of ambient mantle or plume Tp. In all plume models, mantle starting plumes (diameter 300 km) impinge on the base of the lithosphere, and spread laterally over > 1600 km, flowing into the shallowest mantle, and producing the highest volume magmas. In ambient-mantle only models, Archean and Paleoproterozoic Tp values yield significant sub-lithospheric melt volumes, resulting in ‘passive’ geodynamic emplacement of basaltic magmatic provinces, whereas no melts are extracted at > 100 km for Meso-Neoproterozoic and Phanerozoic Tp. This indicates a major transition in non-subduction related continental magmatism from plume and ambient mantle to a plume-dominated source around the Mesoproterozoic. While the experiments presented here show the variation in plume-lithosphere interaction through time, the consistency in melt localisation indicates the lithosphere has been a first-order control on continental magmatism since its establishment in the Mesoarchean.
DS201901-0036
2018
Gorczyk, W.Gorczyk, W., Mole, D.R., Barnes, S.J.Plume lithosphere interaction at craton margins throughout Earth history.Tectonophysics, Vol. 746, pp. 678-694.Mantlecraton

Abstract: Intraplate continental magmatism represents a fundamental mechanism in Earth's magmatic, thermal, chemical and environmental evolution. It is a process intimately linked with crustal development, large-igneous provinces, metallogeny and major global environmental catastrophes. As a result, understanding the interactions of continental magmas through time is vital in understanding their effect on the planet. The interaction of mantle plumes with the lithosphere has been shown to significantly affect the location and form of continental magmatism, but only at modern mantle conditions. In this study, we perform numerical modelling for Late Archean (1600 °C), Paleoproterozoic (1550 °C), Meso-Neoproteroic (1500 °C) and Phanerozoic (1450 °C) mantle potential temperatures (Tp) to assess the time-space magmatic effects of ambient-mantle- and plume- lithosphere interaction over Earth's thermal history. Within these experiments, we impinge a mantle plume, with a time-appropriate Tp, onto a ‘step-like’ lithosphere, to evaluate the effect of craton margins on continental magmatism through time. The results of this modelling demonstrate that lithospheric architecture controls the volume and location of continental magmatism throughout Earth history, irrespective of ambient mantle or plume Tp. In all plume models, mantle starting plumes (diameter 300 km) impinge on the base of the lithosphere, and spread laterally over > 1600 km, flowing into the shallowest mantle, and producing the highest volume magmas. In ambient-mantle only models, Archean and Paleoproterozoic Tp values yield significant sub-lithospheric melt volumes, resulting in ‘passive’ geodynamic emplacement of basaltic magmatic provinces, whereas no melts are extracted at > 100 km for Meso-Neoproterozoic and Phanerozoic Tp. This indicates a major transition in non-subduction related continental magmatism from plume and ambient mantle to a plume-dominated source around the Mesoproterozoic. While the experiments presented here show the variation in plume-lithosphere interaction through time, the consistency in melt localisation indicates the lithosphere has been a first-order control on continental magmatism since its establishment in the Mesoarchean.
DS200712-0374
2007
Gorczyk, W.A.Gorczyk, W.A., Gerya, T.V., Connolly, J.A.D., Burg, J-P., Yuen, D.A.Melting and mixing processes in mantle wedges.Plates, Plumes, and Paradigms, 1p. abstract p. A346.MantleMelting
DS200512-0352
2004
Gordadze, G.N.Gordadze, G.N., Rusinova, G.V.C14 C15 diamantanes in the organic matter of crystalline basement.Geochemistry International, Vol. 42, 11, pp. 1086-1090.Experimental petrology, carbon
DS201706-1075
2017
Gordadze, G.N.Gordadze, G.N., Kerimov, V.Yu., Gaiduk, A.V., Giruts, M.V., Lobusev, M.A., Serov, S.G., Kuznetsov, N.B., Romanyuk, T.V.Hydrocarbon biomarkers and diamondoid hydrocarbons from Late Precambrian and Lower Cambrian rocks of the Katanga Saddle ( Siberian Platform).Geochemistry International, Vol. 55, 4, pp. 360-366.Russia, Siberiadiamondoid

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.
DS1990-0586
1990
Gordeeev, V.A.Gordeeev, V.A., Gorelkin, YY., Nevinny, N.N., Gelfand, R.B., KutenHyperfine interactions of muonium and hydrogen in silicon and diamond-quantum chemical calculationsHyper. Inter, Vol. 60, No. 1-4, August pp. 723-726GlobalDiamond morphology, MuoniuM.
DS2002-0937
2002
Gordeev, E.Levin, V., Park, J., Brandon, M., Lees, J., Peyton, V., Gordeev, E., Ozerv, A.Crust and upper mantle of Kamchatka from teleseismic receiver functionsTectonophysics, Vol. 358, 1-4, pp. 233-265.MantleGeophysics - seismics
DS201412-0307
2014
Gordeev, E.I.Gordeev, E.I., Karpov, G.A., Anikin, L.P., Krivovichev, S.V., Filatov, S.K., Antonov, A.V., Ovsyannikov, A.A.Diamonds in lavas of the Tolbachik fissure eruption in Kamchatka.Doklady Earth Sciences, Vol. 454, 1, pp. 47-49.RussiaTolbachik fissure
DS200512-0851
2004
Gordeeva, V.I.Petrushkin, E.I., Bazarov, L.Sh., Shaygin, V.V., Gordeeva, V.I., Vladykin, N.V.Effect of temperature regime on crystallization of leucite from orendite melt (from experimental data).Russian Geology and Geophysics, Vol. 45, 10, pp. 1159-1166.Mineral chemistry
DS200812-0891
2008
Gordeeva, V.I.Petrudhin, E.I., Bazarov, L.Sh., Gordeeva, V.I., Sharygin, V.V.Crystallization conditions of lamproitic magmas from Zirkel Mesa ( Leucite Hills, USA): dat a on melting experiments.9IKC.com, 3p. extended abstractUnited States, Wyoming, Colorado PlateauLamproite
DS202010-1845
2020
Gordeychik, B.Gordeychik, B., Churikova, T., Shea, T., Kronz, A,m Simakin, A., Worner, G.Fo and Ni relations in olivine differentiate between crystallization and diffusion trends.Journal of Petrology, 10.1093/petrology/egaa083Mantleolivine

Abstract: Nickel is a strongly compatible element in olivine, and thus fractional crystallization of olivine typically results in a concave-up trend on a Fo-Ni diagram. "Ni-enriched" olivine compositions are considered those that fall above such a crystallization trend. To explain Ni-enriched olivine crystals, we develop a set of theoretical and computational models to describe how primitive olivine phenocrysts from a parent (high-Mg, high-Ni) basalt re-equilibrate with an evolved (low-Mg, low-Ni) melt through diffusion. These models describe the progressive loss of Fo and Ni in olivine cores during protracted diffusion for various crystal shapes and different relative diffusivities for Ni and Fe-Mg. In the case when the diffusivity of Ni is lower than that for Fe-Mg interdiffusion, then olivine phenocrysts affected by protracted diffusion form a concave-down trend that contrasts with the concave-up crystallization trend. Models for different simple geometries show that the concavity of the diffusion trend does not depend on the size of the crystals and only weakly depends on their shape. We also find that the effect of diffusion anisotropy on trend concavity is in the same magnitude as the effect of crystal shape. Thus, both diffusion anisotropy and crystal shape do not significantly change the concave-down diffusion trend. Three-dimensional numerical diffusion models using a range of more complex, realistic olivine morphologies with anisotropy corroborate this conclusion. Thus, the curvature of the concave-down diffusion trend is mainly determined by the ratio of Ni and Fe-Mg diffusion coefficients. The initial and final points of the diffusion trend are in turn determined by the compositional contrast between mafic and more evolved melts that have mixed to cause disequilibrium between olivine cores and surrounding melt. We present several examples of measurements on olivine from arc basalts from Kamchatka, and several published olivine datasets from mafic magmas from non-subduction settings (lamproites and kimberlites) that are consistent with diffusion-controlled Fo-Ni behaviour. In each case the ratio of Ni and Fe-Mg diffusion coefficients is indicated to be?
DS1970-0694
1973
Gordeyev, S.G.Gnidchin, V.M., Gordeyev, S.G.The Possibility of Using the Method of Ultra-long Waves And radio Check and Test Point for the Exploration of Kimberlite Pipes.Razved. Vyssh. Uchebn. Zaved. Izv., No. 12, PP. 125-129.Russia, YakutiaKimberlite, Geophysics
DS1996-0544
1996
Gordienko, I.V.Gordienko, I.V.Correlation of Pre-Jurassic sections of ancient continents and microcontinents in East Asia #2Journal of Southeast Asian Earth Sciences, Vol. 13, No. 3/5, pp. 215-221China, MongoliaChina platforms, Mongol Okhotsk fold belt
DS1996-0545
1996
Gordienko, I.V.Gordienko, I.V.Correlation of Pre-Jurassic sections of ancient continents and microcontinents in East Asia. #1Journal of Southeast Asian Earth Sciences, Vol. 12, No. 3-4 pp.215-221.China, MongoliaSiberian Platform, Tectonics
DS201805-0947
2018
Gordienko, V.Gordienko, V.Deep seated processes and diamond bearing rocks.New Concepts in Global Tectonics Journal, Vol. 6, no. 1, pp. 4-20. pdfMantlemagmatism, UHP
DS1994-0883
1994
Gordillo, E.Kay, S.M., Gordillo, E.Pocho volcanic rocks and the melting of depleted continental lithosphere above a shallowly dipping subduction zone in the central AndesContributions to Mineralogy and Petrology, Vol. 117, pp. 25-44Argentina, Central Andes, ChileTectonics, subduction zone, magma source, Sierra de Cordoba
DS1997-0029
1997
Gordine, A.Anderson, J.E., Gordine, A.Environmental regulations affecting the mining industry in RussiaMining in Russia Conference Northern Miner, Oct, Toronto, 12pRussiaEnvironment, Legal
DS1920-0333
1927
Gordon, C.H.Gordon, C.H.Mica Peridotite Dike in Union County, TennesseeGeological Society of America (GSA) Bulletin., Vol. 28, PP. 125-126.United States, Appalachia, TennesseeRelated Rocks, Geology
DS200812-0028
2008
Gordon, G.W.Anbar, A.D., Gordon, G.W.Redox renaissance.Geology, Vol. 36, 3 March pp. 271-271.TechnologyCarbon cycles
DS1920-0334
1927
Gordon, J.Gordon, J.How the First Diamonds Were Found at Alexander BayMin. Ind. Magazine (johannesburg), Vol. 4, P. 270.South AfricaMarine Diamond Placers, History
DS1981-0289
1981
Gordon, L.N.Mccallister, R.H., Gordon, L.N.Subcalcic Diopsides from Kimberlites: Chemistry, Exsolutionmicrostructures, and Thermal History.Contributions to Mineralogy and Petrology, Vol. 78, PP. 118-125.South Africa, Botswana, Tanzania, East Africa, LesothoMicroprobe Analyses, Genesis, Kimberlite
DS1986-0297
1986
Gordon, M.B.Gordon, M.B., Hempton, M.R.Collision induced rifting: the Grenville orogeny and The keweenawan rift of North AmericaTectonophysics, Vol. 127, No. 1-2, July 1, pp. 1-26MidcontinentTectonics
DS1997-0428
1997
Gordon, M.B.Gordon, M.B., Mann, P., Flores, R.Cenozoic tectonic history of the North America - Caribbean plate boundary zone in western CubaJournal of Geophysical Research, Vol. 102, No. 5, May 10, pp. 10, 055-82GlobalTectonics, Plate boundary
DS1950-0390
1958
Gordon, M.JR.Gordon, M.JR., Tracey, J.I.JR., Ellis, M.W.Geology of the Arkansaw Bauxite RegionUnited States Geological Survey (USGS) PROF. PAPER., No. 299, 268P. PP. 60-69 OF INTEREST.United States, Gulf Coast, ArkansasBlank
DS200612-0477
2006
Gordon, R.Gordon, R.New approaches for discovery: an economic look at the impact of new technology applied to wealth creation in exploration.SEG 2006 Conference, Wealth Creation in the Minerals Industry, May 14-16, Keystone Colorado USA, Abtract Volume POSTER only p. 135-137. ( 3p.)GlobalEconomics - technology
DS1987-0147
1987
Gordon, R.G.DeMets, C., Gordon, R.G., Stein, S., Argus, D.F.A revised estimate of Pacific North America motion And implications for western North America plate boundary zonetectonicsGeophysical Research Letters, Vol. 14, No. 9, September pp. 911-914CordilleraTectonics
DS1990-0587
1990
Gordon, R.G.Gordon, R.G.Plate tectonic speed limitsNature, Vol. 349, No. 6304, January 3, pp. 16, 17GlobalTectonics, Dynamics
DS1991-0030
1991
Gordon, R.G.Argus, D.F., Gordon, R.G.Current Sierra Nevada -North America motion from very long baselineinterferometery: implications for the kinematics of the western United StatesGeology, Vol. 19, No. 11, November pp. 1085-1088CordilleraTectonics, Geodynamics
DS1995-0653
1995
Gordon, R.G.Gordon, R.G.Plate motions, crustal and lithospheric mobility, and paleomagnetism:prospective viewpointJournal of Geophysical Research, Vol. 100, No. B12, Dec. 10, pp. 24, 367-92MantleTectonics -plate tectonics, Crustal mobility
DS1995-0654
1995
Gordon, R.G.Gordon, R.G.Is the Colorado Plateau rotating?Eos, Vol. 76, No. 46, Nov. 7. p.F177. Abstract.Colorado PlateauTectonics, Craton
DS1995-0655
1995
Gordon, R.G.Gordon, R.G.Plate motions, crustal and lithospheric mobility and paleomagnetism:prospective viewpoint.Journal of Geophysical Research, Vol. 100, No. B12, Dec. 10, pp. 24, 367-392.Mantle, crustPlate boundaries, interiors, Paleomagnetism -review
DS201012-0148
2010
Gordon, R.G.DeMets, C., Gordon, R.G., Argus, D.F.Geologically current plate motions.Geophysical Journal International, Vol. 181, 1, pp. 1-80.MantleGeodynamics - review tectonics
DS1994-0643
1994
Gordon, S.Gordon, S.Native title, mining and exploration in northern Australia - addressing the problems and benefitsAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 6, Dec. pp. 76-79AustraliaNative, Aboriginal, Legal
DS200912-0655
2009
Gordon, T.M.Russell, J.K., Gordon, T.M.Role of volatiles in kimberlite ascent and eruption.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyMantleThermodynamic ascent
DS1940-0096
1945
Gordon, W.T.Gordon, W.T.A Note on Some Large Diamonds Recently Recovered from the Gravels of the Woyie River in Sierra Leone.Imp. Institute Bulletin., Vol. 43, No. 2, PP. 111-120. PP. 111-120.Sierra Leone, West AfricaGeology, Morphology
DS202011-2063
2020
Gordon-Coker, C.Thurston, M., Young, N., Gordon-Coker, C.Farewell to Wynand Kleingeld.Mathematical Geosciences, Vol. 52, pp. 971-973.GlobalKleingeld
DS1994-1536
1994
Gordton, M.P.Schandl, E.S., Gordton, M.P., Davis, D.W.Albitization at 1700 +- 2Ma in the Sudbury-Wanapitei Lake area:implications deep seated alkalic magmatismCanadian Journal of Earth Sciences, Vol. 31, No. 3, March pp. 597-607OntarioMagmatism, Alkaline
DS2001-0527
2001
GoreJames, D., Rokosky, Nguuri, Gore, Niu, WebbCrustal formation in the Archean: constraints from the southern Africa seismic experiment.Slave-Kaapvaal Workshop, Sept. Ottawa, 2p. abstractSouth Africa, BotswanaGeophysics - seismics, Brief review of crustal structure studies
DS2001-0832
2001
GoreNguuri, T.K., Gore, James, Webb, Wright, Zengeni et al.Crustal structure beneath southern Africa and its implications for the formation and evolution of ...Geophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2501-4.South AfricaTectonics, Craton - Kaapvaal and Zimbabwe
DS201012-0245
2010
Gore, J.Gore, J., James, D.E., Zengeni, T.G., Gwavava, O.Crustal structure of the Zimbabwe craton and the Limpopo belt of southern Africa: new constraints from seismic dat a and implications for its evolution.South African Journal of Geology, Vol. 112, pp. 213-228.Africa, Zimbabwe, South Africa, BotswanaGeophysics - seismics
DS1985-0240
1985
Gore, R.Gore, R.Our Restless Planet EarthNational Geographic., AUGUST, PP. 142-181.GlobalGeotectonics
DS2001-0893
2001
GorelikovaPatyk-Kara, N.G., Gorelikova, Bardeeva, E.G., ShevelevMineralogy of placers: modern approaches and solutionsLithology and Mineral Resources, Vol. 36, No. 5, Sept-Oct. pp. 393-405.GlobalAlluvials, Review
DS1990-0586
1990
Gorelkin, YY.Gordeeev, V.A., Gorelkin, YY., Nevinny, N.N., Gelfand, R.B., KutenHyperfine interactions of muonium and hydrogen in silicon and diamond-quantum chemical calculationsHyper. Inter, Vol. 60, No. 1-4, August pp. 723-726GlobalDiamond morphology, MuoniuM.
DS202111-1759
2021
Gorelova, L.A.Britvin, S., Vlasenko, N.S., Aslandukov, A., Aslandova, A., Dubovinsky, L., Gorelova, L.A., Krzhizhanvskaya, M.G., Vereshchagin, O.S., Bocharov, V.N., Shelukina, Y.S., Lozhkin, M.S., Zaitsev, A.N., Nestola, F.Natural cubic perovskite, Ca(Ti,Si,Cr) O 3-delta, a versatile potential host rock-forming and less common elements up to Earth's mantle pressure.American Mineralogist, doi:10.2138/am-2022-8186 in pressMantleperovskite

Abstract: Perovskite, CaTiO3, originally described as a cubic mineral, is known to have a distorted (orthorhombic) crystal structure. We herein report on the discovery of natural cubic perovskite. This was identified in gehlenite rocks occurring in a pyrometamorphic complex of the Hatrurim Formation (the Mottled Zone), in the vicinity of the Dead Sea, Negev Desert, Israel. The mineral is associated with native ?-(Fe,Ni) metal, schreibersite (Fe3P) and Si-rich fluorapatite. The crystals of this perovskite reach 50 ?m in size and contain many micron sized inclusions of melilite glass. The mineral contains significant amounts of Si substituting for Ti (up to 9.6 wt.% SiO2) corresponding to 21 mol.% of the davemaoite component (cubic perovskite-type CaSiO3), in addition to up to 6.6 wt.% Cr2O3. Incorporation of trivalent elements results in the occurrence of oxygen vacancies in the crystal structure; this being the first example of natural oxygen-vacant ABO3 perovskite with the chemical formula Ca(Ti,Si,Cr)O3-? (? ~ 0.1). Stabilization of cubic symmetry (space group Pm?3m) is achieved via the mechanism not reported so far for CaTiO3, namely displacement of an oxygen atom from its ideal structural position (site splitting). The mineral is stable at atmospheric pressure to 1250±50 °C; above this temperature its crystals fuse with the embedded melilite glass, yielding a mixture of titanite and anorthite upon melt solidification. The mineral is stable upon compression to at least 50 GPa. The a lattice parameter exhibits continuous contraction from 3.808(1) Å at atmospheric pressure to 3.551(6) Å at 50 GPa. The second-order truncation of the Birch-Murnaghan equation of state gives the initial volume V0 equal to 55.5(2) Å3 and room temperature isothermal bulk modulus K0 of 153(11) GPa. The discovery of oxygen-deficient single perovskite suggests previously unaccounted ways for incorporation of almost any element into the perovskite framework up to pressures corresponding to those of the Earth’s mantle.
DS201112-0005
2011
GorevAfanasev, V.P., Lobanov, S.S., Pokhilenko, N.P., Koptil, Mityukhin, Gerasimchuk, Pomazanski, GorevPolygenesis of diamonds in Siberian Platform. Five groups of diamonds have been distinquished.Russian Geology and Geophysics, Vol.l 52, pp. 259-274.Russia, SiberiaDiamond placers, alluvials
DS1988-0261
1988
Gorev, N.I.Gorev, N.I., Manakov, A.V., Ericnshek, I.M., Bardina, E.I., et al.Reflection of the Mirinskoe kimberlite field in the structure of sedimentary cover.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 303, No. 3, pp. 685-689RussiaStructure, Mirinskoe
DS1988-0262
1988
Gorev, N.I.Gorev, N.I., Manakov, A.V., Erincheck, Yu.M., et al.Structural reflection of the Mirnyy kimberlite field in the sedimentarycoverDokl. Acad. Sciences USSR Earth Science Section, Vol. 303, No. 6, pp. 77-80RussiaGeophysics, Structure, Mirnyy
DS1970-0296
1971
Gorina, I.F.Gorina, I.F.The Crystal Morphology of Diamonds from the Anabar-olenek InLeningrad: Arctic Geol. Res. Institute Ussr, PP. 90-L07.RussiaBlank
DS1970-0297
1971
Gorina, I.F.Gorina, I.F.Mineral Thermometry of Diamonds. In: Kimberlite Volcanism And Prospects for Primary Diamond Content in the Northeast Part of the Siberian Platform, Rabkin, M.i.Leningrad: Arctic Geol. Res. Institute Ussr, RussiaBlank
DS1970-0362
1971
Gorina, M.A.Milashev, V.A., Tabunov, S.M., Gorina, M.A., et al.Kimberlite Fields of Northeastern Siberian Platform In: Kimberlite Volcanism and Primary Diamond Content in the Northeast Part of the Siberian PlatformLeningrad: Niiga., PP. 5-42.RussiaBlank
DS201312-0325
2013
Gorkovets, V.Y.Gorkovets, V.Y., Rudashevski, N.S., Rudashevski, V.N., Popov, M.G., Antonov, A.V.Indicator minerals of diamond in the lamproitic diatreme, Kostomuksha region, Karelia.Doklady Earth Sciences, Vol. 450, 1, pp. 475-478.Russia, KareliaLamproite
DS201807-1493
2013
Gorkovets, V.Ya.Gorkovets, V.Ya., Rudashevskii, N.S., Rudashevsky, V.N., Popov, M.G., Antonov, A.A.Indicator minerals in the lamproitic diatreme, Kostomuksha region, Karelia. Doklady Earth Sciences , Vol. 450, 1, pp. 79-90.Russialamproite

Abstract: The mineralogy of a new lamproitic diatreme 200-250 m in diameter and 3 ga in area is studied in detail. The chemical and 3-D mineralogical analysis identify the diatreme rocks as strongly altered olivine lamproites with a large volume (50-60%) of xenoliths of strongly altered spinel (garnet) lherzolites and harzburgites-dunites. Numerous grains-xenocrysts of indicator minerals of diamond have been extracted from the heavy concentrates (the weight of the initial product is 742 g and the size is 100-500 ?m) as a result of hydroseparation: (1) subcalcium (CaOav. 2.6 wt %) high-Cr (Cr2O3 av. 5.3 wt %) pyrope (50 grains); (2) chrome diopside (7 and 8 mol % of kosmochlor and jadeite components, respectively, >40 grains); (3) high-Cr chromite (Cr2O3 > 62 wt %); and (4) picroilmenite (MgO 12-13.8 wt %) and Cr-rutile (Cr2O3 1.1 wt %). Xenocrysts prove the mantle endogene (the level of garnet lherzolites) source of the magmatic center of lamproites and forecast the diamond potential of the new diatreme in the Kostomuksha ore district.
DS1998-0866
1998
GormanLevander, A., Henstock, T.J., Snelson, Keller, GormanThe deep probe experiment: what is the role of inherited structure in thecontinents?Geological Society of America (GSA) Annual Meeting, abstract. only, p.A161.Northwest TerritoriesTectonics, Lithoprobe
DS2002-0298
2002
Gorman, A.Clowes, R.M., Burianyk, M., Gorman, A., KanasewichCrustal velocity structure from Sarex, the southern Alberta Refraction ExperimentCanadian Journal of Earth Science, Vol.39,3,Mar.pp.351-73., Vol.39,3,Mar.pp.351-73.Alberta, MontanaGeophysics - seismics, Loverna Domain, Hearne Province, Vulcan Structure
DS2002-0299
2002
Gorman, A.Clowes, R.M., Burianyk, M., Gorman, A., KanasewichCrustal velocity structure from Sarex, the southern Alberta Refraction ExperimentCanadian Journal of Earth Science, Vol.39,3,Mar.pp.351-73., Vol.39,3,Mar.pp.351-73.Alberta, MontanaGeophysics - seismics, Loverna Domain, Hearne Province, Vulcan Structure
DS1996-0546
1996
Gorman, A.R.Gorman, A.R., et al.DEEP PROBE seismic refraction imaging of the crust and upper mantle of the Archean Hearne Craton.Ross, G.M. Lithoprobe Alberta, No. 51, pp. 27-38.AlbertaGeophysics - seismics, Hearne Craton
DS2000-0352
2000
Gorman, A.R.Gorman, A.R., Clowes, R.M.Deep probe - new insight into the Precambrian development of western NorthAmerica.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 4p. abstract.Alberta, Montana, Wyoming, Northwest TerritoriesGeophysics - seismics - Deep Probe, Model - structure
DS200612-0478
2006
Gorman, A.R.Gorman, A.R., Nemeth, B., Clowes, R., Hajnal, Z.An investigation of upper mantle heterogeneity beneath the Archean and Proterozoic crust of western Canada from lithoprobe controlled source seismic experiments.Tectonophysics, Vol. 416, 1-4, April 5, pp. 187-207.Canada, Alberta, Saskatchewan, Northwest TerritoriesGeophysics - seismics
DS2002-0596
2002
Gorman, D.Gorman, D., Clowes, Ellis, Henstock, Spence, KellerDeep probe: imaging the roots of western North AmericaCanadian Journal of Earth Science, Vol.39,3,Mar.pp.375-98., Vol.39,3,Mar.pp.375-98.Alberta, Montana, Colorado, CordilleraGeophysics - seismics, Tectonics
DS2002-0597
2002
Gorman, D.Gorman, D., Clowes, Ellis, Henstock, Spence, KellerDeep probe: imaging the roots of western North AmericaCanadian Journal of Earth Science, Vol.39,3,Mar.pp.375-98., Vol.39,3,Mar.pp.375-98.Alberta, Montana, Colorado, CordilleraGeophysics - seismics, Tectonics
DS2003-0484
2003
Gorman, J.Gorman, J.Diamond in the roughSciences News, Vol. 163, 20, p. 310.GlobalNews item
DS200412-0695
2003
Gorman, J.Gorman, J.Diamond in the rough.Science News, Vol. 163, 20, p. 310.TechnologyNews item
DS1999-0259
1999
Gorman, P.Gorman, P., Wells, D.Technical due diligence in the mining sector: separating the Mines from the holes in the ground.North Atlantic Mineral Symposium, Sept., abstracts pp. 118-119.GlobalMining - reserve, processing, overview, Economics - not specific to diamonds
DS200612-0479
2006
Gorman, P.J.Gorman, P.J., Kerrick, D.M., Connolly, J.A.D.Modeling open system metamorphic decarbonation of subducting slabs.Geochemistry, Geophysics, Geosystems: G3, Vol. 7, Q04007MantleSubduction, fluids, CO2, geothermometry
DS200412-0696
2004
Gornostayev, S.S.Gornostayev, S.S., Walker, R.J., Hanski, E.J., Popovchenko, S.E.Evidence for the emplacement of ca. 3.0 Ga mantle derived mafic ultramafic bodies in the Ukrainian Shield.Precambrian Research, Vol. 132, 4, July 15, pp.349-362.Europe, UkraineTectonics, chromitite
DS1990-0205
1990
Gornov, P.Yu.Biryukov, V.M., Gornov, P.Yu., Ivanov, G.I., Kosygin, Yu.A.First diamond finds in plutonic xenoliths at the eastern margin of the Siberian craton #2Doklady Academy of Science USSR, Earth Science Section, Vol. 305, No. 2, Sept. pp. 122-125RussiaEclogite, Kimberlite breccia
DS2000-0353
2000
Gornova, M.A.Gornova, M.A., Glazunov, O.M.Mantle peridotites and pyroxenites of the Saramanta Massif in the Precambrian gneiss granitoid complex.Russian Geology and Geophysics, Vol. 40, No. 7, pp. 986-999.RussiaPeridotites
DS2000-0915
2000
Gornova, M.A.Soloveva, L.V., Gornova, M.A., Lozhkin, V.I.Trace elements in the xenoliths of pyroxenites, eclogites and mafic granulites from Udachnaya ...Doklady Academy of Sciences, Vol. 373A, No. 6, Aug-Sept. pp.1004-7.Russia, YakutiaGeochemistry, Deposit - Obnazhennaya, Udachnaya
DS2001-0397
2001
Gornova, M.A.Gornova, M.A., Solovjeva, L.V., Glazunov, BelozerovaFormation of Precambrian lithosphere mantle geochemical analysis of coarseAlkaline Magmatism -problems mantle source, pp. 223-41.Russia, SiberiaCraton, Geochemistry
DS2001-0398
2001
Gornova, M.A.Gornova, M.A., Tsypukov, Sandimirova, SmirnovaMelting of the Precambrian mantle: geochemistry of residual peridotites from peripheral blocks of PlatformDoklady Academy of Sciences, Vol. 378, No. 4, May-June pp. 379-82.Russia, SiberiaPeridotites, Mantle - melting
DS2001-1103
2001
Gornova, M.A.Soloveva, L.V., Gornova, M.A.Geochemical prototypes of basic granulites from Yakutian kimberlitesDoklady Academy of Sciences, Vol. 377, No. 2, Feb-Mar. pp.204-6.Russia, YakutiaChemistry - granulites
DS200412-1874
2004
Gornova, M.A.Soloveva, L.V., Gornova, M.A., Markova, M.E., Lozhkin, V.I.Geochemical identification of granulites in xenoliths from Yakutian kimberlites.Geochemistry International, Vol. 42, 3, pp. 220-235.Russia, YakutiaGeochemistry
DS200412-1875
2004
Gornova, M.A.Soloveva, L.V., Gornova, M.A., Egorov, K.N., Smironov, E.V.REE and HFSE distribution in rocks and minerals from granular peridotite xenoliths in the Udachnaya kimberlite pipe.Doklady Earth Sciences, Vol. 395, 4, March-April, pp. 456-460.Russia, YakutiaGeochemistry
DS200412-1876
2004
Gornova, M.A.Soloveva, L.V., Gornova, M.A., Lozhkin, V.I.Geochemical identification of granulites in xenoliths from Yakutian kimberlites.Geochemistry International, Vol. 42, 3, pp. 220-235.Russia, YakutiaGeochemistry
DS200512-0353
2002
Gornova, M.A.Gornova, M.A., Solovjeva, L.V.Application of rare element composition of garnet and clinopyroxene from peridotite xenoliths ( Udachnaya kimberlite) for modeling of primitive mantle meltingDeep Seated Magmatism, magmatism sources and the problem of plumes., pp. 148-162.RussiaREE - melting
DS200512-0354
2001
Gornova, M.A.Gornova, M.A., Solovjeva, L.V., Glazunov, O.M., Belozerova, O.Yu.Formation of Precambrian lithosphere mantle - geochemical analysis of coarse grained peridotites from kimberlites, Siberian Craton.Alkaline Magmatism and the problems of mantle sources, pp. 223-241.Russia, SiberiaGeochemistry
DS200512-1025
2005
Gornova, M.A.Solovjeva, L.V., Egorov, K.N., Kostrovitsky, S.I., Gornova, M.A.The effect of different metasomatic processes on geochemical heterogeneity of upper mantle of the Siberian craton.GAC Annual Meeting Halifax May 15-19, Abstract 1p.Russia, Yakutia, SakhaUdachnaya, geochemistry
DS200712-0375
2007
Gornova, M.A.Gornova, M.A., Polozov, A.G., Ignatev, A.V., Velivetskaya, T.A.Peridotite nodules from the Udachnaya kimberlite pipe, nonmantle oxygen isotope ratios in garnets.Doklady Earth Sciences, Vol. 415, 5, pp. 777-781.RussiaDeposit - Udachnaya
DS200812-0907
2008
Gornova, M.A.Polozov, A.C., Sukhov, S.S., Gornova, M.A., Grishina, S.N.Salts from Udachnaya East kimberlite pipe ( Yakutia, Russia): occurrences and mineral composition.9IKC.com, 3p. extended abstractRussiaDeposit - Udachnaya
DS200912-0352
2009
Gornova, M.A.Kamenetsky, V.S., Mass, R., Kamenetsky, M.B., Paton, C., Phillips, D., Golovin, A.V., Gornova, M.A.Chlorine from the mantle: magmatic halides in the Udachnaya-East kimberlite, Siberia.Earth and Planetary Science Letters, Vol. 285, pp. 96-104.Russia, SiberiaDeposit - Udachnaya
DS201212-0376
2012
Gornova, M.A.Kostrovitskii, S.I., Soloveva, L.V., Gornova, M.A., Alymova, N.V., Yakolev, D.A., Ignative, A.V., Velivetskaya, T.A., Suvorova, L.F.Oxygen isotope composition in minerals of mantle parageneses from Yakutian kimberlites.Doklady Earth Sciences, Vol. 444, 1, pp. 579-584.Russia, YakutiaDeposit - Udachnaya, Komsomolskaya
DS201212-0378
2012
Gornova, M.A.Kostrovitsky, S.I.,Gornova, M.A.,Solovyevas, L.V., Yakolev, D.A.Isotope heterogeneity from oxygen in rocks of lithospheric mantle.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussiaDeposit - Udachnaya
DS201312-0326
2013
Gornova, M.A.Gornova, M.A., Belyaev, V.A., Belozerova, O.Yu.Textures and geochemistry of the Saramta peridotites ( Siberian craton): melting and refertilization during early evolution of the continental lithospheric mantle.Journal of Asian Earth Sciences, Vol. 62, pp. 4-17.RussiaHarzburgite
DS201905-1014
2019
Gornova, M.A.Abersteiner, A., Kamenetsky, V.S., Goemann, K., Golovin, A.V., Gornova, M.A.Polymineralic inclusions in kimberlite hosted megacrysts: implications for kimberlite melt evolution.Lithos, doi.101016/j.lithos .2019.04.004 42p.Canada, Northwest Territories, Russiadeposit - Diavik, Jericho, Leslie, Udachnaya East

Abstract: Megacrysts are large (cm to >20?cm in size) mantle-derived crystals, which are commonly entrained by kimberlite magmas, comprising of olivine, orthopyroxene, clinopyroxene, phlogopite, garnet, ilmenite and zircon as common phases. Numerous studies have shown megacrysts to contain polymineralic inclusions, which have been interpreted to represent entrapped kimberlite melt. To constrain the origin of these inclusions in megacrysts and their relationship to kimberlite magmatism, we present a detailed petrographic and geochemical study of clinopyroxene and olivine megacrysts and their hosted inclusions from the Diavik, Jericho, Leslie (Slave Craton, Canada) and Udachnaya-East (Siberian Craton, Russia) kimberlites. The studied megacrysts are between 1 and 3?cm in size and representative of both the Cr-rich and Cr-poor suites. Megacrysts contain two types of inclusions: i. Large (<0.5-5?mm in size) round-to-irregular shaped polymineralic inclusions, which are composed of minerals similar to the host kimberlite groundmass, and consist of olivine, calcite, spinel, perovskite, phlogopite and apatite (± serpentine, alkali-carbonates, alkali-chlorides, barite). ii. Swarms/trails of ‘micro melt inclusions’ (MMI; <1-5??m in size), which surround polymineralic inclusions, veins and fractures, thereby forming a ‘spongy’ texture. MMIs generally contain multiphase assemblages similar to polymineralic inclusions as well as various additional phases, such as alkali-carbonates or alkali-chlorides, which are typically absent in polymineralic inclusions and the surrounding kimberlite groundmass. Textural and geochemical evidence suggests that polymineralic inclusions in megacrysts crystallised from kimberlite melt, which infiltrated along fracture/vein networks. The polymineralic inclusion assemblages resulted from disequilibria reactions between the host megacryst and infiltrating kimberlite melt, which was likely enhanced by rapidly changing conditions during magmatic ascent. The connectivity of polymineralic inclusions to the kimberlite groundmass via network veins/fractures suggests that they are susceptible to infiltrating post-emplacement fluids. Therefore, the vast majority of polymineralic inclusions are unlikely to represent ‘pristine’ entrapped kimberlite melt. In contrast, MMIs are isolated within megacrysts (i.e. not connected to fractures/veins and therefore shielded from post-magmatic fluids) and probably represent entrapped remnants of the variably differentiated kimberlite melt, which was more enriched in alkalis-Cl-S-CO2 than serpentinised polymineralic inclusions and the host rocks exposed at Earth's surface as kimberlites.
DS200812-0597
2008
Gornova, M.A.A.A.Kostrovitsky, S.A.I.A., Alymova, N.A., Yakolev, D.A.A., Solvaceva, L.A.V.A., Gornova, M.A.A.A.Origin of garnet megacrysts from kimberlites.Doklady Earth Sciences, Vol. 420, 1, pp. 636-640.RussiaPetrology
DS1992-0589
1992
Gorobets, B.S.Gorobets, B.S., Portnov, A.M.Luminescent anomalies in the earth crust during distant searching fororesRussian Geology and Geophysics, Vol. 33, No. 2, pp. 37-43Russia, Commonwealth of Independent States (CIS)Photoluminescent, Carbonatite
DS1989-0528
1989
Gorogotskaya, L.I.Gorogotskaya, L.I., Kvasnitsa, V.N., Hadezhdina, Ye.D.Orientation relations of graphite-lonsdaleite-diamond during natural transformations in shock waves.(Russian)Mineral. Zhurn., (Russian), Vol. 11, No. 1, pp. 26-33RussiaLonsdaleite, Mineraloggy
DS202010-1846
2020
Gorojovsky, L.Gorojovsky, L., Alard, O.Optimization of laser and mass spectrometer parameters for the in situ analysis of Rb/Sr ratios by LA-ICP-MS/MS. ( mentions Monastery phlogopite megacrystJournal of Analytical Atomic Spectrometry, 10.1039/DOJA00308E 15p. PdfGlobalgeochronology

Abstract: The Rb-Sr isotopic system is widely used in geochronology. Conventionally burdened by the isobaric overlap of 87Rb and 87Sr, Rb/Sr dating in situ has only recently become achievable with the newly developed LA-ICP-MS/MS system. Simultaneous use of reactive gas (e.g. O2, N2O, or CH3F) during LA-ICP-MS/MS analysis has been shown to resolve the Rb and Sr overlap, thus now making available key spatial and temporal information that can only be accessed via in situ analytical techniques. The accuracy and precision of Rb/Sr ratios and ages are largely dependent on the laser and ICP-MS/MS parameters used. Rb/Sr isotopic analysis by LA-ICP-MS/MS is a recently developed technique and these parameters are yet to be fully explored. We investigate the effects of laser wavelength (213 nm and 193 nm), laser frequency (5 Hz and 10 Hz), laser carrier gas (He, H2, and N2), dwell time, and external standard calibration on the accuracy and precision of 87Rb/86Sr and 87Sr/86Sr ratios and ages. These analytical conditions have been tested on the commercially available reference materials: NIST SRM 610, USGS BHVO-2G, and pressed nano-particulate powder tablet CRPG Mica-mg, as well as a Monastery phlogopite megacryst. Our results show that accuracy and precision for 87Rb/86Sr and 87Sr/86Sr ratios are significantly affected by laser wavelength and frequency. Variation in these parameters can strongly magnify any matrix effects which directly influences the ability to apply effective external corrections. We obtain the best accuracy and precision when using a 193 nm laser wavelength, ablating at a frequency of 5 Hz (0.30 2s% and 0.15 2s% for 87Rb/86Sr and 87Sr/86Sr ratios, respectively). Meanwhile we find that age accuracy is highly dependant on external reference materials. When these analytical settings are put to test on the Monastery phlogopite, we obtain an age of 90.0 ± 3.6 (0.24% accuracy) when using mica-mg (87Rb/86Sr) and NIST 610 (87Sr/86Sr) as external standards.
DS1988-0263
1988
Gorokhov, N.P.Gorokhov, N.P., Tiunov, A.A., Kistanova, T.I., Sorokina, V.D.Use of phosphates in the flotation of pyrochlorefromcarbonatitepipes.(Russian)Tsvetn. Met. (Moscow), (Russian), No. 12, pp. 87-88RussiaCarbonatite, Mineral processing applic
DS1975-0087
1975
Gorokhov, S.S.Gorokhov, S.S.Bedrock Sources of Small Diamonds in Clastic SedimentsDoklady Academy of Science USSR, Earth Science Section., Vol. 225, No. 1-6, PP. 70-72.RussiaKimberlite, Placers
DS1981-0393
1981
Gorokhov, S.S.Spetsius, Z.V., Zayachkovskiy, A.A., Gorokhov, S.S.Discovery of a Diamond Dniester Type in Eclogite Xenoliths with Some placers.Mineral. Sbornik L'vov, Vol. 35, No. 1, PP. 71-73.RussiaBlank
DS1980-0058
1980
Gorokov, S.S.Belimenko, L.D., Gorokov, S.S., Samoylovich, M.I.Characteristics of Real Structure of Small DiamondsTsnigri, No. 153, PP. 31-35.RussiaBlank
DS200912-0260
2008
Goroshko, M.V.Goroshko, M.V., Malyshev, Y.F.Regional potassic metasomatism and metallogeny of Precambrian structural-stratigraphic unconformity zones ( southeastern Siberian Craton).Doklady Earth Sciences, Vol. 423, 2, pp. 1459-1461.RussiaMetasomatism
DS1997-0134
1997
GorozhaninaBrown, D., Alvarez-Marron, Perez-Estaun, A., GorozhaninaGeometric and kinematic evolution of the foreland thrust and fold belt In the southern UralsTectonics, Vol. 16, No. 3, June, pp. 551-562GlobalTectonics
DS2000-0016
2000
Gorozhanina, Y.Alvarez-Marron, J., Brown, D., Gorozhanina, Y.Accretionary complex structure and kinematics during Paleozoic arc continent collision in the southern UralsTectonophysics, Vol. 235, No. 1-2, Oct. 15, pp. 175-Russia, UralsTectonics
DS200712-0116
2006
Gorozhanina, Y.Brown, D., Spadea, P., Puchkov, V., Alvarez-Marron, J., Herrington, R., Willner, A.P., Hetzel, R., Gorozhanina, Y., Juhlin, C.Arc continent collision in the southern Urals.Earth Science Reviews, in press availableRussia, UralsBaltica tectonics, UHP, geochemistry
DS1997-0429
1997
Gorring, M.L.Gorring, M.L., Kay, S.M., Zeitler, P.K., et al.Neogene Patagonian plateau lavas: continental magmas associated with ridge collision Chile Triple junctionTectonics, Vol. 16, No. 1, Feb. pp. 1-17ChileTectonics, Subduction
DS2000-0354
2000
Gorring, M.L.Gorring, M.L., Kay, S.M.Carbonatite metasomatized peridotite xenoliths from southern Patagonia: implications for magmatism...Contributions to Mineralogy and Petrology, Vol. 140, No. 1, pp. 55-72.GlobalLithospheric processes and Neogene plateau magmatism, Carbonatite
DS2001-0399
2001
Gorring, M.L.Gorring, M.L., Kay, S.M.Mantle processes and sources of Neogene slab window magmas from southern Patagonia, Argentina.Journal of Petrology, Vol. 42, No. 6, pp. 1067-94.Argentina, PatagoniaSubduction
DS1998-1467
1998
GorshkovTitkov, S., Gorshkov, Vinokov, Bershov, Solodov, SivtsovCarbonado from Yakutian diamond deposits (Russia): microinclusions, impurities and paragenetic centres.7th International Kimberlite Conference Abstract, pp. 914-6.Russia, YakutiaCarbonado, Deposit - Udachnaya
DS2001-1160
2001
GorshkovTitkov, S.V., Gorshkov, Vinokurov, Bershov, SolodovGeochemistry and genesis of carbonado from Yakutian diamond depositsGeochemistry International, Vol. 39, No. 3, pp. 228-36.Russia, YakutiaMicroinclusions, Carbonado
DS2000-0355
2000
Gorshkov, A. BaoGorshkov, A. Bao, Titkov, Ryabchikov, Magazina, SivtsovComposition of mineral inclusions and formation of polycrystalline diamond aggregates ( Bort) Shengli pipeGeochemistry International, Vol. 38, No. 7, pp. 698-705.ChinaMineralogy - bort, Deposit - Shengli, Shenli
DS1995-0656
1995
Gorshkov, A.I.Gorshkov, A.I., Seliverstov, V.A., et al.Crystallochemistry and genesis of carbonado from the melanocratic basaltoids of the Avacha volcano.Geology of Ore Deposits, Vol. 37, No. 1, Jan-Feb. pp. 44-55.Russia, KamchatkaCarbonado, Basalt
DS1995-0657
1995
Gorshkov, A.I.Gorshkov, A.I., Seliverstov, V.A., Sivtsov, A.V.Crystal chemistry and mineralogy of Moissanite from alkaline ultrabasic volcanic complex (Kamchatka). #2Petrology, Vol. 37, No. 4, pp. 313-321.Russia, KamchatkaMineral chemistry, Moissanite
DS1995-0658
1995
Gorshkov, A.I.Gorshkov, A.I., Titkov, S.K., Sivtsov, A.V., BershovNative metals chromium, nickel and iron in cryptocrystalline diamonds (Carbonado) fromYakutia.Proceedings of the Sixth International Kimberlite Conference Extended, p. 187.Russia, YakutiaDiamond morphology, Carbonado
DS1996-0547
1996
Gorshkov, A.I.Gorshkov, A.I., Seliverstov, V.A., Sivstov, A.V., LapinaThe first discovery of native aluminum in carbonadoGeology of ore deposits, Vol. 38, No. 4, pp. 341-343.RussiaCarbonado, Kedrovka River
DS1997-0430
1997
Gorshkov, A.I.Gorshkov, A.I., Bao Yunan, Berhov, L.V., et al.Inclusions in diamond from the Liaoning deposit, and their geneticmeaning.Geochemistry International, Vol. 35, No. 1, pp. 51-57.ChinaDiamond inclusions, Deposit - Liaoning
DS1997-0431
1997
Gorshkov, A.I.Gorshkov, A.I., Bao, Y.N., Berhsov, L.V., RyabchikovInclusions of native metals and other minerals in diamond from Kimberlite pipe 50, Lianong China.Geochemistry International, Vol. 35, No. 8, pp. 596-703.ChinaDiamond inclusions, Deposit - Liaong Pipe 50
DS1997-0432
1997
Gorshkov, A.I.Gorshkov, A.I., Berhsov, L.V.Carbonado from the Lenkoish region, Bahia State (Brasil) mineralinclusions, physical, geochemical ...Geology of Ore Deposits, Vol. 39, No. 3, pp. 229-236.Brazil, BahiaCarbonado, Deposit - Lenkoish region
DS1997-1019
1997
Gorshkov, A.I.Seliverstov, V.A., Gorshkov, A.I., Shcheka, SivtsovDiamonds and carbonado of the Primorskii Krai: mineralogy, crystal chemistry and genesis.Geology of Ore Deposits, Vol. 38, No. 6, pp. 429-441.ChinaDiamond morphology, Crystallography
DS1998-0524
1998
Gorshkov, A.I.Gorshkov, A.I., Vinokurov, S.F., et al.Polycrystalline diamond from the Udachnaya pipe: mineralogical, geochemical and genetic charcteristics.Lithology and MIneral Resources, Vol. 33, No. 6, Nov-Dec. pp. 525-538.Russia, YakutiaMineralogy, geochemistry, Deposit - Udachanaya
DS1998-1547
1998
Gorshkov, A.I.Vinokurov, S.F., Gorshkov, A.I., Lapina, M.I.Diamonds from kimberlite Diatreme 50, Liaoning Province, China:microtextural, mineralogical, geneticGeochemistry International, Vol. 36, No. 8, Aug. 1, pp. 676-683.ChinaTextures, petrology, Deposit - Diatreme 50
DS1999-0260
1999
Gorshkov, A.I.Gorshkov, A.I., Bao, Y.N., Magazina, L.O.Polycrystalline diamond aggregate (bort) from Shanley kimberlite pipe, China: growth features, genesisGeochemistry International, Vol. 37, No. 1, Jan. pp. 75-81.ChinaDiamond morphology - bort, Deposit - Shanley
DS2002-0598
2002
Gorshkov, A.I.Gorshkov, A.I., Titkov, Vinokurov, Ryabchikov, BaoStudy of cubic diamond crystal from a placer in northern Chin a by analytical electron microscopy...Geochemistry International, Vol.40,3,pp.299-305., Vol.40,3,pp.299-305.ChinaDiamond - morphology, neutron activation analysis, Alluvials
DS2002-0599
2002
Gorshkov, A.I.Gorshkov, A.I., Titkov, Vinokurov, Ryabchikov, BaoStudy of cubic diamond crystal from a placer in northern Chin a by analytical electron microscopy...Geochemistry International, Vol.40,3,pp.299-305., Vol.40,3,pp.299-305.ChinaDiamond - morphology, neutron activation analysis, Alluvials
DS2002-0600
2002
Gorshkov, A.I.Gorshkov, A.I., Titkov, Vinolurov, Ryabchikov, BaoStudy of a cubic diamond crystal from a placer by analytical electron microscopy neuton activation anal.Gochemistry International, Vol.40, 3, pp.299-305.China, northernAlluvials - diamond morphology
DS2002-0601
2002
Gorshkov, A.I.Gorshkov, A.I., Zinchuk, Kotelnikov, ShlykovA new ordered mixed layer lizardite saponite mineral from South African kimberlitesDoklady, Vol.382, 1, Jan-Feb.pp. 86-90.South AfricaMineralogy
DS2002-0602
2002
Gorshkov, A.I.Gorshkov, A.I., Zinchuk, N.N., Kotelnikov, D.D., Shlykov, V.G., ZhukhlistovA new ordered mixed layer lizardite saponite mineral from South African kimberliteDoklady Earth Sciences, Vol.382,1,pp.86-90.South AfricaMineralogy, Deposit -
DS2003-1381
2003
Gorshkov, A.I.Tikov, S.V., Zudin, N.G., Gorshkov, A.I., Sivtsov, A.V., Magazina, L.O.An investigation into the cause of colour in natural black diamonds from SiberiaGems & Gemology, Vol. 39,3, Fall, pp. 200-209.Russia, SiberiaMineral inclusions - Mir
DS2003-1563
2003
Gorshkov, A.I.Zinchuk, N.N., Kotelnikov, D.D., Gorshkov, A.I.Identification and genesis of the mixed layer lizardite saponite phase in a kimberlite pipeLithology and Mineral Resources, Vol. 38, 1, pp. 74-81.South AfricaPetrography
DS200412-0697
2004
Gorshkov, A.I.Gorshkov, A.I., Bershov, I.V., Titkov, S.V., Vinokurov, S.F.Mineral inclusions and impurities in diamonds from lamproites of the Argyle pipe, West Australia.Geochemistry International, Vol. 41, 12, pp. 1143-1151.AustraliaDeposit - Argyle, mineralogy
DS200412-1995
2003
Gorshkov, A.I.Tikov, S.V., Zudin, N.G., Gorshkov, A.I., Sivtsov, A.V., Magazina, L.O.An investigation into the cause of colour in natural black diamonds from Siberia.Gems & Gemology, Vol. 39,3, Fall, pp. 200-209.Russia, SiberiaMineral inclusions - Mir
DS200412-2000
2004
Gorshkov, A.I.Titkov, S.V., Gorshkov, A.I., Magazina, L.O., Sivtsov, A.V., Zakharchenko, O.D.Shapeless dark diamonds ( Yakutites) from placers of the Siberian platform and criteria of their impact origin.Geology of Ore Deposits, Vol. 46, 3, pp. 191-201.Russia, SiberiaDiamond morphology
DS200612-0480
2006
Gorshkov, A.I.Gorshkov, A.I., Titkov, S.V., Bao, Y.N., Ryabchikov, I.D., Magazina, L.O.Micro inclusions in diamonds of octahedral habit from kimberlites of Shandong province, eastern China.Geology of Ore Deposits, Vol. 48, 4, pp. 326-China, ShandongDiamond morphology, inclusions
DS200612-1429
2006
Gorshkov, A.I.Titkov, S.V., Gorshkov, A.I., Solodova, Ryabchikov, Magazina, Sivtsov, Gasanov, Sedova, SamosorovMineral Micro inclusions in cubic diamonds from the Yakutian deposits based on analytical electron microscopy data.Doklady Earth Sciences, Vol. 410, no. 7 July-August, pp. 1106-1108.Russia, YakutiaDiamond inclusions
DS200712-1083
2006
Gorshkov, A.I.Titkov, S.V., Gorshkov, A.I., Zudin, N.G.Micro inclusions in dark gray diamond crystals of octahedral habit from Yakutian kimberlites.Geochemistry International, Vol. 44, 11, pp. 1121-1128.Russia, YakutiaDiamond morphology
DS200712-1084
2006
Gorshkov, A.I.Titkov, S.V., Solodova, Y.P., Gorshkov, A.I., Magaina, L.O., Sivtsov, A.V., Sedova, E.A., Gasanov, SamosorovInclusions in white gray diamonds of cubic habit from Siberia.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.127-8. abstract onlyRussiaDiamond morphology
DS200612-0481
2006
Gorshkov, A.L.Gorshkov, A.L., Titkov, S.V., Bao, Y.N., Ryabchikov, I.D., Magazina, L.O.Micro inclusions in diamonds of octahedral habit from kimberlites of Shandong Province, eastern China.Geology of Ore Deposits, Vol. 48, 4, pp 326-334.ChinaDiamond crystallography
DS1982-0086
1982
Gorshkov, Y.N.Baratov, R.B., Klimov, G.K., Dusmatov, V.D., Gorshkov, Y.N.New Dat a on Explosion Pipes of Karkul Konchoch in Southern Tien Shan.Doklady Academy of Sciences Nauk TADZH. SSR., Vol. 25, No. 10, PP. 604-607.RussiaPetrology, Kimberlite, Pamirs, Karakul, Konchoch
DS1982-0085
1982
Gorshkov, YE. N.Baratov, B.B., Klimov, G.K., Sushmatov, V.D., Gorshkov, YE. N.New dat a on explosion pipes of Karakul Konchoch in southern TienShan.(Russian)Doklady Academy of Sciences Nauk. Tadzhikskoy SSSR, (Russian), Vol. 25, No. 10, pp. 604-607RussiaBlank
DS1995-0659
1995
Gorshov, A.I.Gorshov, A.I., Selivers, Sivtsov, A.V.Crystal chemistry and mineralogy of moissanite from alkaline ultrabasic volcanic complex (Kamchatka). #1Geology of Ore Deposits, Vol. 37, No. 4, Jul-Aug. pp. 313-321.Russia, KamchatkaGeochemistry, Moissanite
DS1995-0660
1995
Gorshov, A.I.Gorshov, A.I., Titkov. S.V., Pleshakov, A.M., et al.Inclusions of native metals and other mineral phases into carbonado From the Ubnagi region (Central Africa).Geology of Ore Deposits, Vol. 38, No. 2, pp. 131-136.Central African RepublicCarbonado, Mineralogy, microscopy, Ubangi area
DS1996-0548
1996
Gorshov, A.N.Gorshov, A.N., Titkov, S.V., Marfunin, A.S.The first finds of native chromium, nickel and alpha iron in carbonado from the Diamond deposits of Yakutia.Geochemistry International, Vol. 33, No. 1, Jan. 1, pp. 59-63.Russia, YakutiaCarbonado, Native chromium, nickel, iron
DS201212-0456
2012
Gorter, J.McInnis, B., Evans, N., Jourdan, F., McDonald, B., Gorter, J., Mayers, C., Wilde, S.A Tertiary record of Australian plate motion from ages of Diamondiferous alkalic intrusions.Goldschmidt Conference 2012, abstract 1p.AustraliaGeochronology - Fohn
DS2002-0603
2002
Gorter, J.D.Gorter, J.D., Glikson, A.Y.Fohn lamproite and a possible late Eocene pre- Miocene diatreme field, Northern Bonaparte Basin, Timor Sea.Australian Journal of Earth Sciences, Vol. 49, 5, pp. 847-68.Australia, Timor SeaGeophysics - seismics, Lamproite, diatreme
DS1987-0123
1987
Gorton, M.Corriveau, L., Gorton, M.Potential economic significance of Precambrian potassic plutons in the central metasedimentary belt, Grenville Province of Western QuebecGeological Survey of Canada Paper, No. 87-1A, pp. 897-899QuebecLamproite, Carbonatite
DS1989-0297
1989
Gorton, M.Corriveau, L., Gorton, M.Proterozoic alkaline plutons southwest Grenville: a record of ultrapotassic magmas and tectonic settingGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A71. (abstract.)OntarioBlank
DS1989-0298
1989
Gorton, M.P.Corriveau, L., Gorton, M.P.Potassic alkaline and shoshonitic plutonism in the southwest GrenvilleprovinceGeological Society of America (GSA) Annual Meeting Abstracts, Vol. 21, No. 6, p. A107. AbstractOntarioShoshonite, Trace elements
DS1993-0290
1993
Gorton, M.P.Corriveau, L., Gorton, M.P.Coexiting potassium-rich alkaline and shoshonitic magmatism of arc affinities In the Proterozoic: a reassessment of syenitic stocks in the southwestern GrenvilleProvinceContribution to Mineralogy and Petrology, Vol. 113, pp. 262-279OntarioAlkaline, shoshonite, Ultrapotassic, potassic
DS1994-0346
1994
Gorton, M.P.Corriveau, L., Amelin, Y., Gorton, M.P., Morin, D.Geochemical constraints on Proterozoic potassium-rich alkaline and shoshonitic magmas evolution in the S.W. Grenville Province.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.OntarioAlkaline rocks, Shoshonite
DS1995-0661
1995
Gorton, M.P.Gorton, M.P., Schandl, E.S.An unusual sink for rare earth elements: the rhyolite basalt contact of the Archean Winston Lake VMS..Economic Geology, Vol. 90, No. 7, November pp. 2065-72Ontariorare earth elements (REE), metamorphism, massive sulphide, copper, lead, zinc, Deposit -Winston Lake
DS1994-1656
1994
GoryainoSobolev, N.V., Shatskiy, V.S., Vavilov, MM.A., GoryainoZirconium from metamorphic rocks of folded regions a unique container of inclusions diamond, coesite (Russian)Doklady Academy of Sciences Nauk.(Russian), Vol. 334, No. 4, Feb. pp. 488-492.RussiaMetamorphic rocks, Coesite
DS201507-0325
2015
Goryainov, P.M.Mikhailova, J.A., Kalashnikov, A.O., Sokharev, V.A., Pakhomovsky, Y.A., Konopleva, N.G., Yakovenchuk, V.N., Bazai, A.V., Goryainov, P.M., Ivanyuk, G.Yu.3D mineralogical mapping of the Kovdor phoscorite-carbonatite complex, Russia.Mineralium Deposita, In press available. 19p.RussiaCarbonatite
DS201511-1849
2016
Goryainov, P.M.Kalashnikov, A.O., Yakovenchuk, V.N., Pakhomovsky, Y.A.A., Bazai, A.V., Sokharev, V.A., Konopleva, N.G., Mikhailova, J.A., Goryainov, P.M., Ivanyuk, G.Yu.Scandium of the Kovdor baddeleyite apatite magnetite deposit ( Murmansk region, Russia): mineralogy, spatial distribution, and potential source.Ore Geology Reviews, Vol. 72, pp. 532-537.RussiaCarbonatite
DS201602-0226
2016
Goryainov, P.M.Mikhailova, J.A., Kalashnikov, A.O., Sokharev, V.A., Pakhomovsky, Y.A., Konopleva, N.G., Yakovenchuk, V.N., Bazai, A.V., Goryainov, P.M., Ivanyuk, G.Y.3D mineralogical mapping of the Kovdor phoscorite carbonatite complex ( Russia).Mineralium Deposita, Vol. 51, 1, pp. 131-149.RussiaDeposit - Kovdor

Abstract: The Kovdor baddeleyite-apatite-magnetite deposit in the Kovdor phoscorite-carbonatite pipe is situated in the western part of the zoned alkali-ultrabasic Kovdor intrusion (NW part of the Fennoscandinavian shield; Murmansk Region, Russia). We describe major intrusive and metasomatic rocks of the pipe and its surroundings using a new classification of phoscorite-carbonatite series rocks, consistent with the IUGS recommendation. The gradual zonation of the pipe corresponds to the sequence of mineral crystallization (forsterite-hydroxylapatite-magnetite-calcite). Crystal morphology, grain size, characteristic inclusions, and composition of the rock-forming and accessory minerals display the same spatial zonation pattern, as do the three minerals of economic interest, i.e. magnetite, hydroxylapatite, and baddeleyite. The content of Sr, rare earth elements (REEs), and Ba in hydroxylapatite tends to increase gradually at the expense of Si, Fe, and Mg from early apatite-forsterite phoscorite (margins of the pipe) through carbonate-free, magnetite-rich phoscorite to carbonate-rich phoscorite and phoscorite-related carbonatite (inner part). Magnetite displays a trend of increasing V and Ca and decreasing Ti, Mn, Si, Cr, Sc, and Zn from the margins to the central part of the pipe; its grain size initially increases from the wall rocks to the inner part and then decreases towards the central part; characteristic inclusions in magnetite are geikielite within the marginal zone of the phoscorite-carbonatite pipe, spinel within the intermediate zone, and ilmenite within the inner zone. The zoning pattern seems to have formed due to both cooling and rapid degassing (pressure drop) of a fluid-rich magmatic column and subsequent pneumatolytic and hydrothermal processes.
DS201604-0611
2016
Goryainov, P.M.Ivanyuk, G.Yu., Kalashnikov, A.O., Pakhomovsky, Ya.A., Mikhailov, J.A., Yakovenchuk, V.N., Konopleva, N.G., Sokharev, V.A., Bazai, A.V., Goryainov, P.M.Economic minerals of the Kovdor baddeleyite apatite magnetite deposit, Russia: mineralogy, spatial distribution and ore processing optimization.Ore Geology Reviews, in press available 73p.RussiaDeposit - Kovdor

Abstract: The comprehensive petrographical, petrochemical and mineralogical study of the Kovdor magnetite-apatite-baddeleyite deposit in the phoscorite-carbonatite complex (Murmansk Region, Russia) revealed a spatial distribution of grain size and chemical composition of three economically extractable minerals — magnetite, apatite, and baddeleyite, showing that zonal distribution of mineral properties mimics both concentric and vertical zonation of the carbonatite-phoscorite pipe. The marginal zone of the pipe consists of (apatite)-forsterite phoscorite carrying fine grains of Ti-Mn-Si-rich magnetite with ilmenite exsolution lamellae, fine grains of Fe-Mg-rich apatite and finest grains of baddeleyite, enriched in Mg, Fe, Si and Mn. The intermediate zone accommodates carbonate-free magnetite-rich phoscorites that carry medium to coarse grains of Mg-Al-rich magnetite with exsolution inclusions of spinel, medium-grained pure apatite and baddeleyite. The axial zone hosts carbonate-rich phoscorites and phoscorite-related carbonatites bearing medium-grained Ti-V-Ca-rich magnetite with exsolution inclusions of geikielite-ilmenite, fine grains of Ba-Sr-Ln-rich apatite and comparatively large grains of baddeleyite, enriched in Hf, Ta, Nb and Sc. The collected data enable us to predict such important mineralogical characteristics of the multicomponent ore as chemical composition and grain size of economic and associated minerals, presence of contaminating inclusions, etc. We have identified potential areas of maximum concentration of such by-products as scandium, niobium and hafnium in baddeleyite and REEs in apatite.
DS201605-0847
2016
Goryainov, P.M.Ivanyuk, G.Yu., Kalashnikov, A.O., Pakhomovsky, Ya.A., Mikhailova, J.A., Yakovenchuk, V.N., Konopleva, N.G., Sokharev, V.A., Bazai, A.V., Goryainov, P.M.Economic minerals of the Kovdor baddeleyite apatite magnetite deposit, Russia: mineralogy, spatial distribution and ore procesing optimization.Ore Geology Reviews, Vol. 77, pp. 279-311.RussiaCarbonatite, Kovdor

Abstract: The comprehensive petrographical, petrochemical and mineralogical study of the Kovdor magnetite-apatite-baddeleyite deposit in the phoscorite-carbonatite complex (Murmansk Region, Russia) revealed a spatial distribution of grain size and chemical composition of three economically extractable minerals — magnetite, apatite, and baddeleyite, showing that zonal distribution of mineral properties mimics both concentric and vertical zonation of the carbonatite-phoscorite pipe. The marginal zone of the pipe consists of (apatite)-forsterite phoscorite carrying fine grains of Ti-Mn-Si-rich magnetite with ilmenite exsolution lamellae, fine grains of Fe-Mg-rich apatite and finest grains of baddeleyite, enriched in Mg, Fe, Si and Mn. The intermediate zone accommodates carbonate-free magnetite-rich phoscorites that carry medium to coarse grains of Mg-Al-rich magnetite with exsolution inclusions of spinel, medium-grained pure apatite and baddeleyite. The axial zone hosts carbonate-rich phoscorites and phoscorite-related carbonatites bearing medium-grained Ti-V-Ca-rich magnetite with exsolution inclusions of geikielite-ilmenite, fine grains of Ba-Sr-Ln-rich apatite and comparatively large grains of baddeleyite, enriched in Hf, Ta, Nb and Sc. The collected data enable us to predict such important mineralogical characteristics of the multicomponent ore as chemical composition and grain size of economic and associated minerals, presence of contaminating inclusions, etc. We have identified potential areas of maximum concentration of such by-products as scandium, niobium and hafnium in baddeleyite and REEs in apatite.
DS201608-1413
2016
Goryainov, P.M.Ivanyuk, G.Yu., Kalashnikov, A.O., Pakhomovsky, Ya.A., Mikhailova, J.A., Yakovenchuk, V.N., Konopleva, N.G., Sokharev, V.A., Bazai, A.V., Goryainov, P.M.Economic minerals of the Kovdor baddeleyite apatite magnetite deposit, Russia: mineralogy, spatial distribution and ore processing optimization.Ore Geology Reviews, Vol. 77, pp. 279-311.RussiaDeposit - Kovdor

Abstract: The comprehensive petrographical, petrochemical and mineralogical study of the Kovdor magnetite-apatite-baddeleyite deposit in the phoscorite-carbonatite complex (Murmansk Region, Russia) revealed a spatial distribution of grain size and chemical composition of three economically extractable minerals — magnetite, apatite, and baddeleyite, showing that zonal distribution of mineral properties mimics both concentric and vertical zonation of the carbonatite-phoscorite pipe.The marginal zone of the pipe consists of (apatite)-forsterite phoscorite carrying fine grains of Ti-Mn-Si-rich magnetite with ilmenite exsolution lamellae, fine grains of Fe-Mg-rich apatite and finest grains of baddeleyite, enriched in Mg, Fe, Si and Mn. The intermediate zone accommodates carbonate-free magnetite-rich phoscorites that carry medium to coarse grains of Mg-Al-rich magnetite with exsolution inclusions of spinel, medium-grained pure apatite and baddeleyite. The axial zone hosts carbonate-rich phoscorites and phoscorite-related carbonatites bearing medium-grained Ti-V-Ca-rich magnetite with exsolution inclusions of geikielite-ilmenite, fine grains of Ba-Sr-Ln-rich apatite and comparatively large grains of baddeleyite, enriched in Hf, Ta, Nb and Sc. The collected data enable us to predict such important mineralogical characteristics of the multicomponent ore as chemical composition and grain size of economic and associated minerals, presence of contaminating inclusions, etc. We have identified potential areas of maximum concentration of such by-products as scandium, niobium and hafnium in baddeleyite and REEs in apatite.
DS201705-0884
2017
Goryainov, S.Ugapeva, S., Goryainov, S., Afanasiev, V., Ponkratov, K.Raman mapping of mechanical stress field in diamond around a chromite inclusion.European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 11676 AbstractTechnologyDiamond inclusions
DS202111-1770
2021
Goryainov, S.Grishina, S., Goryainov, S., Oreshonkov, A., Karmanov, N.Micro-Raman study of cesanite ( Ca2Na3(OH)(SO4)3) in chloride segregations from Udachnaya-East kimberlites.Journal of Raman Spectroscopy, 11p. PdfRussiadeposit - Udachnay-East

Abstract: Cesanite (Ca2Na3(OH)(SO4)3), a rare mineral, has been found in a few places restricted to a geothermal field and caves. We report the new occurrence of cesanite in quite different geological site—within sulfate-rich melt inclusions in chloride segregations from kimberlites of Udachnaya-East pipe (Siberia). Two halite generations: ?esanite free and ?esanite-bearing, were distinguished in concentrically zonal segregations according to the results of the mineral and sulfate melt inclusion study by micro-Raman spectroscopy and SEM-EDS. We have applied the Raman spectroscopy and first principles calculations to understand structural and vibrational properties of cesanite daughter mineral in polyphase sulfate inclusions. Polarized spectra provided additional information on the overlapped components of the spectral profile. The Raman spectra of cesanite in the range of OH stretching vibrations are reported for the first time. The study aims to clarify the source of the Na-S-Cl-enrichment in the Udachnaya-East pipe, which is highly discussed.
DS1991-1625
1991
Goryainov, S.V.Sobolev, N.V., Shatskiy, V.S., Vavilov, M.A., Goryainov, S.V.Coesite inclusion in zircon from diamond containing gneisses of KokchetavMassif- lst find of coesite in metamorphic rocks of the USSR. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 321, No. 1, pp. 184-188. # hb124RussiaCoesite, Metamorphic rocks
DS2001-0350
2001
Goryainov, S.V.Fursenko, B.A., Goryainov, S.V., Sobolev, N.V.high pressure coesite inclusions in diamond: Raman spectroscopyDoklady Academy of Sciences, Vol. 379A, No. 6, July-August pp. 749-51.GlobalCoesite, Diamond - inclusions
DS2001-0400
2001
Goryainov, S.V.Goryainov, S.V., Belitski, I.A., Likhacheva, FursenkoRaman spectroscopy of high pressure phase transition in analcime and leuciteRussian Geology and Geophysics, Vol. 41, No. 5, pp. 673-81.GlobalSpectroscopy
DS2002-1298
2002
Goryainov, S.V.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
DS201412-0308
2014
Goryainov, 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
DS201608-1447
2016
Goryainov, S.V.Ugapeva, S.S., Pavlushin, A.D., Goryainov, S.V., Afanasiev, V.P., Poikilenko, N.P.Comparative characteristics of diamonds with olivine inclusions from the Ebelyakh placer and kimberlite pipes of the Yakutian Diamondiferous province.Doklady Earth Sciences, Vol. 468, 1, pp. 473-477.RussiaDeposit - Mir, Aykhal, Udachnaya, XXII Congress

Abstract: The results of morphological examination and the character of the structural orientation and estimation of residual pressure calculated from spectra of combination dispersion in olivine inclusions within diamonds of the Ebelyakh placer and kimberlite pipes of the Yakutian Diamondiferous Province are presented. The data analysis aimed at revealing indications of similarity and/or differences between diamonds from the pipes and the placer. Differences in the structural orientation and spectra of combination dispersion of the inclusions of olivine in dodecahedroids of placers of the northeastern part of the Siberian Platform support the assumption of their non-kimberlite nature.
DS201812-2858
2018
Goryainov, S.V.Ovsyuk, N.N., Goryainov, S.V., Likhacheva, A.Y.Raman scattering of impact diamonds. PopagaiDiamond & Related Materials, doi.1016/j.diamond .2018.11.017 24p. Russialonsdaleite
DS201901-0051
2019
Goryainov, S.V.Ovsyuk, N.N., Goryainov, S.V., Likhacheva, A.Y.Raman scattering of impact diamonds. LonsdaleiteDiamond & Related Materials, Vol. 91, pp. 207-212.Russia, SiberiaPopigai

Abstract: We report the results of a study of the polycrystalline powder of the diamond-lonsdaleite from the Popigai crater (Siberia) using UV micro-Raman spectroscopy and high-resolution synchrotron X-ray diffraction. By subtracting two experimental Raman spectra of diamond-lonsdaleite samples with close amounts of diamond and lonsdaleite, we were able to identify the polytypic composition of impact diamonds in contrast to the method of X-ray diffraction. We have managed to get for the first time the spectrum of “pure” lonsdaleite. Its deconvolution has allowed us to identify all the three Raman - active vibrational modes E2g, A1g, and E1g whose positions agree well with the results of ab initio calculations.
DS1995-1793
1995
GoryaynovSobolev, N.V., Shatskiy, V.S., Vavilov, GoryaynovZircon in high pressure metamorphic rocks in folded regions as a unique container of inclusions.....Doklady Academy of Sciences, Vol. 336, No. 4, Nov., pp. 79-85.Russia, Kokchetau MassifCoesite, diamond, Inclusions
DS1994-1657
1994
Goryaynov, S.Sobolev, N.V., Shatsky, V.S., Vavilov, M.A., Goryaynov, S.A coesite inclusion in zircon from diamond containing gneiss of Kokchetav:first find coesite in metamorphic rocks of the USSRDoklady Academy of Sciences USSR, Earth Science Section, Vol. 322, No. 1, pp. 123-127.RussiaDiamond inclusions, Coesite
DS201412-0316
2014
Goryinov, S.V.Grishina, S.N., Polozov, A.G., Mazurov, M.P., Goryinov, S.V.Genesis of chloride-carbonate segregations of the Udachnaya-East pipe.Doklady Earth Sciences, Vol. 458, 1, pp. 1129-1131.Russia, YakutiaDeposit - Udachnaya-East
DS1998-0715
1998
GorzynskyKaminsky, F.V., Gorzynsky, Sablukova, Sablukov, et al.Primary sources of diamonds in the Birim area, Ghana7th International Kimberlite Conference Abstract, pp. 389-91.GhanaDiamond morphology, alluvials, placers, Deposit - BiriM.
DS2003-0485
2003
Goscombe, B.Goscombe, B., Hand, M., Gray, D., Mawby, J.Metamorphic architecture of a transpressional orogen: the Kaoko belt, NamibiaJournal of Petrology, Vol. 44, 4, pp. 679-712.NamibiaTectonics
DS2003-0486
2003
Goscombe, B.Goscombe, B., Hand, M., Gray, D.Structure of the Kaoko Belt, Namibia: progressive evolution of a classic transpressionalJournal of Structural Geology, Vol. 25, 7, pp. 1049-81.NamibiaTectonics
DS200412-0698
2003
Goscombe, B.Goscombe, B., Hand, M.,Gray, D., Mawby, J.Metamorphic architecture of a transpressional orogen: the Kaoko belt, Namibia.Journal of Petrology, Vol. 44, 4, pp. 679-712.Africa, NamibiaTectonics
DS200412-0699
2003
Goscombe, B.Goscombe, B., Hand, M., Gray, D.Structure of the Kaoko Belt, Namibia: progressive evolution of a classic transpressional orogen.Journal of Structural Geology, Vol. 25, 7, pp. 1049-81.Africa, NamibiaTectonics
DS200712-0190
2007
Goscombe, B.Clark, C., Hand, M., Kelsey, D.E., Goscombe, B.Linking crustal reworking to terrane accretion.Journal of Geological Society of London, Vol. 164, 5, pp. 937-940.MantleAccretion
DS200912-0261
2009
Goscombe, B.D.Goscombe, B.D., Gray, D.R.Metamorphic response in orogens of different obliquity, scale and geometry.Gondwana Research, Vol. 15, 2, pp. 151-167.MantleUHP
DS201412-0248
2015
Goscombe, B.D.Foster, D.A., Goscombe, B.D., Newstead, B., Mapani, B., Mueller, P.A., Gregory, L.C., Muvangua, E.U-Pb age and Lu-Hf isotopic dat a of detrital zircons from the Neoproterozoic Damara sequence: implications for Congo and Kalahari before Gondwana.Gondwana Research, Vol. 28, 1, pp. 179-190.AfricaGeochronology
DS2002-0652
2002
GoseHanson, 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
DS200612-0527
2006
GoseHanson, R.E., Harmer, R.E., Blenkinsop, T.G., Bullen, D.S., Dalziel, Gose, Hall, Kampunzu, Key, MukwakwamiMesoproterozoic intraplate magmatism in the Kalahari Craton: a review.Journal of African Earth Sciences, Vol. 46, 1-2, pp. 141-167.Africa, South AfricaMagmatism
DS200612-0528
2006
GoseHanson, R.E., Harmer,Blenkinsop, Bullen, Dalziel, Gose, Hall, Kampunzu, Key, Mukwakwami, Munyaniwa, Pancake, Seidel, WardMesoproterozoic intraplate magmatism in the Kalahari Craton: a review.Journal of African Earth Sciences, In press available,Africa, South AfricaAlkaline rocks, carbonatite, Premier kimberlite cluster
DS201511-1878
2015
Gose, 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.
DS201807-1494
2018
Gose, J.Gose, J., Schmadicke, E.Water in corporation in garnet: coesite versus quartz ecologite from Erzgebirge and Fichtelbirge.Journal of Petrology, Vol. 59, 2, pp. 207-232.Europe, Germanycoesite
DS201911-2558
2019
Gose, J.Schmadicke, E., Gose, J.Low water contents in garnet of orogenic peridotite: clues for an abyssal or mantle-wedge origin?European Journal of Mineralogy, Vol. 31, pp. 715-730.Europe, Germanywater

Abstract: Data on water in nominally anhydrous minerals (NAMs) of orogenic garnet-bearing ultramafic rocks (GBU) are extremely rare. In this study, garnet of peridotite and pyroxenite from Erzgebirge (EG), Germany, and two peridotite samples from Alpe Arami (AA), Switzerland, were analyzed by infrared (IR) spectroscopy. Garnet from EG peridotite and pyroxenite yielded IR absorption bands at 3650 ± 10 cm?1 (type I) and in the wavenumber range of 3570-3630 cm?1 (type II) that are ascribed to structural hydroxyl (colloquially “water”). Additional broad band’s centered at <3460 cm?1, present in about half of the samples, are related to molecular water (MW). The content of structural H2O defined by band types I + II is low (3-68 ppm) in all EG samples. Structural water is negatively correlated to Mg and Ti and positively to Y and HREE in EG garnet. Including molecular water, a pronounced positive correlation between H2O and Li is observed. Because the intensity of the type II band is enhanced in domains with molecular water, the primary, peak metamorphic H2O content in EG garnet was probably as low as 0-11 ppm. Equally low contents of structural water are present in AA garnet (10-13 ppm) in which molecular water is negligible. Such concentrations are distinctly lower than the water storage capacity of garnet at the relevant pressure. Water loss upon decompression cannot serve as an explanation for the low contents because, on the contrary, post-peak-metamorphic influx of H2O led garnet to take up secondary structural water. Hence, the results are interpreted as an indication of severe water deficiency at peak metamorphism. Notably, the obtained data agree with the H2O content of 6 ppm reported in garnet from Cima di Gagnone peridotite, which originated as abyssal peridotite. It remains unknown if these low contents are typical for an abyssal, low-pressure protolith but, if the rocks were part of the lowermost, most hydrated portion of the mantle wedge, they are expected to contain much more water. Given that garnet in basaltic coesite eclogite from the Erzgebirge is equally water-deficient as the GBU samples from the same unit, it is at least a possibility that both rock types share a low-pressure origin in an oceanic setting.
DS200412-0788
2004
Gose, W.A.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
DS201112-0410
2011
Gose, W.A.Hanson, R.E., Rioux, M., Gose, W.A., Blackburn, T.J., Bowring, S.A., Mukwakwami, J., Jones, D.L.Paleomagnetic and geochronological evidence for large scale post 1.88 Ga displacement between Zimbabwe and Kaapvaal Cratons along the Limpopo belt.Geology, Vol.39, 5, pp. 487-490.Africa, South Africa, ZimbabweGeochronology
DS201312-0328
2013
Gose, W.A.Gose, W.A., Hanson, R.E., Harmer, R.E., Seidel, E.K.Reconnaissance paleomagnetic studies of Mesoproterozoic alkaline igneous complexes in the Kaapvaal craton, South Africa.Journal of African Earth Sciences, Vol. 85, pp. 22-30.Africa, South AfricaGeophysics - magnetics
DS1988-0720
1988
Goslin, J.Unternehr, P., Curie, D., Olivet, J.L., Goslin, J., Beuzart, P.South Atlantic fits and intraplate boundaries in Africa andSouthAmericaTectonophysics, Vol. 155, No. 1-4, Dec. 1, pp. 169-180Africa, South AmericaTectonics
DS1992-0590
1992
Gosnold, D.Jr.Gosnold, D.Jr., Sweeney, J.J.Heat flow in the Williston BasinEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 322SaskatchewanLithoprobe, Heat Flow
DS1990-0588
1990
Gosnold, W.D.Gosnold, W.D.Heat flow in the Great Plains of the United StatesJournal of Geophysical Research, Vol. 95, January 10, pp. 353-374Midcontinent, United StatesHeat Flow, Midcontinent, Great Basin
DS201911-2528
2019
Goss, H.Goss, H.This is how the world moves.EOS, 100, doi.org/10.1029/2019EO134611Globalgeophysics
DS202002-0189
2019
Goss, H.Goss, H.The shape of the world.EOS, 100, Dec. 31, http://doi.org/ 10.1029/2019EO138179Mantlegeodynamics
DS202008-1397
2020
Goss, H.Goss, H.A dive into the deep Earth.Eos, 101, doi.org/10.1029 /2020EO145467 1p. Mantlemineralogy

Abstract: In July, Eos looks at the incredible capabilities scientists have developed to recreate the enormous pressures and temperatures that exist far below the planet’s surface.
DS2003-0487
2003
Goss, J.P.Goss, J.P., Coomer, B.J., Jones, R., Fall, C.J., Briddon, P.R., Oberg, S.Extended defects in diamond: the interstitial plateletPhysical Review, Vol. 67, 16, 15p.GlobalBlank
DS200412-0700
2003
Goss, J.P.Goss, J.P., Coomer, B.J., Jones, R., Fall, C.J., Briddon, P.R., Oberg, S.Extended defects in diamond: the interstitial platelet.Physical Review Letters, Vol. 67, 16, 15p.TechnologyDiamond - morphology
DS200512-0355
2004
Goss, J.P.Goss, J.P., Briddon, P.R., Papagiannidis, S., Jones, R.Interstitial nitrogen and its complexes in diamond.Physical Review Letters, Vol. 70, 23, pp. 235208.Diamond inclusions
DS201112-0382
2011
Goss, J.P.Goss, J.P., Ewels, C.P., Briddon, P.R., Fritsch, E.Bistable N2-H complexes: the first proprosed structure of a H-related colour causing defect in diamond.Diamond and Related Materials, Vol. 20, 7, pp. 896-901.TechnologyDiamond chameleon
DS202004-0497
2020
Goss, J.P.Ashfold, M.N.R., Goss, J.P., Green, B., May, P.W., Newton, M.E., Peaker, C.V.Nitrogen in diamond.Chemical Reviews, Vol. 120, 4, 10.1021/ acs.chemrev.9b00578 50p. PdfGlobalHPHT, CVD, synthetics

Abstract: Nitrogen is ubiquitous in both natural and laboratory-grown diamond, but the number and nature of the nitrogen-containing defects can have a profound effect on the diamond material and its properties. An ever-growing fraction of the supply of diamond appearing on the world market is now lab-grown. Here, we survey recent progress in two complementary diamond synthesis methods: high pressure high temperature (HPHT) growth and chemical vapor deposition (CVD), how each is allowing ever more precise control of nitrogen incorporation in the resulting diamond, and how the diamond produced by either method can be further processed (e.g., by implantation or annealing) to achieve a particular outcome or property. The burgeoning availability of diamond samples grown under well-defined conditions has also enabled huge advances in the characterization and understanding of nitrogen-containing defects in diamond alone and in association with vacancies, hydrogen, and transition metal atoms. Among these, the negatively charged nitrogen-vacancy (NV-) defect in diamond is attracting particular current interest in account of the many new and exciting opportunities it offers for, for example, quantum technologies, nanoscale magnetometry, and biosensing.
DS2001-0406
2001
Gosse, J.C.Gray, J.T., Gosse, J.C., Marquette, G.Weathering zones in the Torngat Mountains Labrador, ice sheet thickness and basal thermal regime.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.54, abstract.Quebec, Ungava, LabradorGeomorphology, Laurentide Ice Sheet
DS2003-1178
2003
Gosselin, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., LapointeHeat flow in the western Superior province of the Canadian ShieldJournal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003GLO17386Ontario, Manitoba, SaskatchewanGeothermometry
DS200412-1683
2003
Gosselin, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., Lapointe, R.Heat flow in the western Superior province of the Canadian Shield.Journal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003 GLO17386Canada, Ontario, Manitoba, SaskatchewanGeothermometry
DS200412-1187
2004
Gosselin, P.Lydon, J.W., Goodfellow, W.D., Dube, B., Paradis, S., Sinclair, W.D., Corrivea, L., Gosselin, P.A preliminary overview of Canada's mineral resources. ( Diamond mentioned).Geological Survey of Canada, Open File 4668, 1 CD $ 20.00 ( pfd of poster, 20p. reptCanadaPoster - resources
DS1995-0662
1995
Gossler, J.Gossler, J., Kind, R.Seismological evidence for a correlation between lithosphere and mantle transition zone.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 703-704.MantleGeophysics -seismics, Lithosphere
DS1995-0663
1995
Gossler, J.Gossler, J., Kind, R.Seismic evidence for very deep roots of continents #1Eos, Vol. 76, No. 46, Nov. 7. p.F422. Abstract.MantleRoots, Geophysics -seismic
DS1996-0549
1996
Gossler, J.Gossler, J., Kind, R.Seismic evidence for very deep roots of continents #2Earth and Planetary Science Letters, Vol. 138, No. 1/4, Feb. 1, pp. 1-14.MantleGeophysics -seismics, Geodynamics
DS1975-1037
1979
Gostin, V.A.Gravenor, C.P., Gostin, V.A.Mechanisms to Explain the Loss of Heavy Minerals from Upper paleozoic Tillites of South Africa and Australia and the Late Precambrian Tillites of Australia.Sedimentology, Vol. 26, PP. 707-717.Australia, South AfricaHeavy Mineral Concentrates
DS2000-1015
2000
Gostin, V.A.Williams, G.E., Gostin, V.A.Mantle plume uplifts in the sedimentary record : origin of kilometer deep canyons within late Neoproterozoic...Journal of Geological Society of London, Vol. 157, No. 4, July pp. 759-68.Australia, SouthTectonics, Plumes
DS201912-2786
2019
Gostlin, K.Gostlin, K., Brenton, K., Liu, W., Clark, L.Gahcho Kue mine update.Yellowknife Forum NWTgeoscience.ca, abstract volume p. 57.Canada, Northwest Territoriesdeposit - Gahcho Kue

Abstract: Gahcho Kué Mine is owned as a joint venture between Mountain Province Diamonds Inc. and De Beers Canada Inc. Located about 280 km northeast of Yellowknife, it is Canada’s newest diamond mine and the world’s largest in the last 14 years. After two years of construction, commercial operations began in September 2016. As the mine enters into its fourth year of operation, De Beers is pleased to provide an update on the current mine operations, updated mine plan, safety, environment, and social performance.
DS201801-0026
2017
Goswami, R.Jadhav, G.N., Viladkar, S.G., Goswami, R., Badhe, K.Fluid melt inclusions petrography of primary calcites from carbonatites of Amba Dongar, Gujarat India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 15.Indiadeposit - Amba Dongar

Abstract: The Amba Dongar Carbonatite complex consists of sovites which are dominantly composed of calcite along with pyrochlore, phlogopite, apatite, barite, ankerite and haematite and minor opaques such as magnetite, chalcopyrite and pyrite. Two distinct types of texture are present in these carbonatites- a mosaic of equigranular calcite crystals and porphyritic texture. Silicate melt inclusions are observed in primary minerals viz. apatite and calcites. These are small droplets of silicate melt entrapped during the growth of the minerals. In this case carbonatite-alkaline silicate melt inclusions are entrapped predominantly in calcite crystals. Dominantly these calcite host minerals are predominantly containing fluid inclusions along with halite, sylvite and minor nahcolite as daughter crystals. The presence of calcite with nahcolite indicates the coexistence of a Ca-rich, alkali-bearing carbonatite melt phase. The melt inclusions are heated upto 1100 °C and the carbonate melt inclusions appear to be homogenized around 950 °C. This fall within the range of melting temperature of a carbonatite melt. In addition to these, three types of fluid inclusions were also observed in host calcite they are i) monophase, ii) biphase and iii) polyphase types of fluid inclusions. The fluid inclusions contain CO2 gas, Li-K carbonate phases and fergusonite based on Micro-Laser- Raman. Carbon dioxide is the dominant gas phase in most of the fluid inclusions, indicating high temperature and deep mantle source(?). The fluid inclusions have formed from a primary mother liquor that has separated out from the early formed carbonatitic melt. This fluid was either formed just after the formation of melt inclusions or during simultaneous crystallization from a carbonatitic or to be more precise carbonatiticpegmatite melt(?).The presence of both melt and fluid inclusions in these primary calcite host minerals indicates the presence of a carbonatitic-pegmatitic fluid, which must have got separated out from the early formed carbonatite-alkaline silicate magma.
DS202106-0945
2021
Goswami, V.Joshi, K.B., Goswami, V., Bannerji, U.S., Shankar, R.Recent developments in instrumentation and its application in absolute dating: historical perspective and overview.** not specific to diamondsJournal of Asian Earth Sciences, Vol. 211, 104690, 23p. PdfGlobalradiometric dating

Abstract: The discovery of radioactivity in the early 20th century led to the development of several radiometric dating methods (e.g., Rb-Sr, Sm-Nd, Re-Os, U-Pb, etc.). These radiometric dating methods are frequently used in earth science studies to constrain the deposition/formation timing of various natural archives (e.g., bulk rocks, minerals, carbonaceous materials, detrital clastic sedimentary materials, ore deposits, hydrocarbon deposits). The last few decades have witnessed significant improvements in overall accuracy and precision of these absolute radiometric dating methods due to continuous developments and refinements in sample processing and analytical techniques. In this contribution, we discuss some of the frequently used radiometric dating techniques for obtaining absolute ages in various natural archives and associated advancements in the instrumentation. The present attempt emphasizes on a multi-mineral and multi-isotopic approach with continuous developments in obtaining better precision and accuracy in the ages through improved analytical and measurement protocols that are the pre-requisite in absolute dating.
DS201412-0892
2006
Goth, K.Suhr, P., Goth, K., Lorenz, V., Suhr, S.Long lasting subsidence and deformation in and above maar-diatreme volcanoes - a never ending story.Zeitschrift der Deutschen Gesellschaft fur Geowissenschaften , Vol. 157, no. 3, pp. 491-511.Europe, GermanyMaar-diatremes
DS1983-0474
1983
Goto, A.Nagata, J., Goto, A., Obata, M.The Parabolic Pattern of Chromium Partioning Observed Between Pyroxenes and Spinel from Ultramafic Rocks and its Petrologic Significance.Contributions to Mineralogy and Petrology, Vol. 82, No. 1, PP. 42-51.GlobalMineral Chemistry, Mineralogy
DS1990-0589
1990
Goto, A.Goto, A., Tatsuim, Y.Stability of chlorite in the upper mantleAmerican Mineralogist, Vol. 75, No. 1-2, January-February pp. 105-108GlobalMantle, Magma genesis
DS1988-0721
1988
Goto, K.Uto, K., Hirai, H., Goto, K., Arai, S.K-Ar ages of carbonate and mantle nodule bearing lamprophyre dikes fromShingu, central Shikoku, southwest JapanGeochemical JOurnal, Vol. 21, No. 6, pp. 283-290JapanBlank
DS1988-0501
1988
Gotovtse, V.V.Nekrasov, I.J., Iakovlev, J.V., Pavlova, L.A., Gotovtse, V.V.Uncommon inclusions in native gold from Mir pipe kimberlites. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 303, No. 5, pp. 1209-1213RussiaGold, Deposit -Mir
DS1984-0487
1984
Gotovtsev, V.V.Marshintsev, V.K., Nikishova, L.V., Gotovtsev, V.V.Serpentine Filling the Needle Channels in Olivine of the Udachnaia Vostochnaia Pipe.Doklady Academy of Sciences AKAD. NAUK. SSSR., Vol. 277, No. 3, PP. 697-700.RussiaBlank
DS1986-0298
1986
Gotovtsev, V.V.Gotovtsev, V.V., Vladimirov, B.M., et al.System of conjugated kimberlite bodies of the Udachnaya piperegion.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 286, No. 6, pp. 1481-1487RussiaBlank
DS1986-0529
1986
Gotovtsev, V.V.Marshintsev, V.K., Nikishova, L.V., Gotovtsev, V.V.Serpentine filling needle shaped channels in olivine from the Udachnaya east pipeDoklady Academy of Science USSR, Earth Science Section, Vol. 277, March pp. 170-174RussiaUdachnaya, Mineralogy
DS1988-0502
1988
Gotovtsev, V.V.Nekrasov, I.Ya., Yakolev, Ya.V., Pavlova, L.A., Gotovtsev, V.V.Unusual inclusions in native gold from the Mir kimberlite pipeDokl. Acad. Sciences USSR Earth Science Section, Vol. 303, No. 6, pp. 160-164RussiaDiamond inclusions, Gold
DS1989-1505
1989
Gottfried, D.Tollo, R.P., Gottfried, D.Early Jurassic quartz normative magmatism of the eastern North Americanprovince: evidence for independent magmas and distinct sourcesNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 270 Abstract held June 25-July 1United States, Appalachia, MidcontinentTectonics, Magma
DS200512-0356
2004
Gottikh, R.P.Gottikh, R.P., Pisotskii, B.I., Zhuravlev, D.Z.Trace element distribution in the kimberlite bitumen and basalt bitumen systems in diatremes of the Siberian Craton.Doklady Earth Sciences, Vol. 399A, Nov-Dec. pp. 1222-1226.RussiaMineralogy - bitumen
DS200612-0482
2006
Gottikh, R.P.Gottikh, R.P., Pisotskii, B.I., Kulakova, I.I.Geochemistry of reduced fluids from alkaline igneous rocks of the Khibiny Pluton.Doklady Earth Sciences, Vol. 407, 2, Feb-Mar. pp. 298-303.RussiaMagmatism
DS1993-0043
1993
Gottlieb, A.Arnold, R., Gottlieb, A.Trashing the economy.. how runaway environmentalism is wrecking AmericaMerrill Press, 660p. $ 20.00United StatesBook -Table of contents, Environmental
DS1981-0192
1981
Gottliebsen, R.Greenwood, R., Gottliebsen, R.Cra and Ashton Crack Down on Northern MiningBusiness Review., JULY 24TH. PP. 11-12.Australia, Western AustraliaHistory, Company Investment
DS1993-0648
1993
Gotts, N.G.Helden, G. von, Gotts, N.G., Bowers, M.T.Experimental evidence for the formation of fullerenes by collisional heating of carbon rings in the gas phaseNature, Vol. 363, No. 6424, May 6, pp. 60-63GlobalCVD.
DS200612-0483
2006
Gottschaldt, K.D.Gottschaldt, K.D., Walzer, U., Hendel, R.F., Stegman, D.R., Baumgartner, J.R., Muhlhaus, H.B.Stirring in 3 d spherical models of convection in the Earth's mantle.Philosophical Magazine, Vol. 86, no. 21-22, pp. 3175-3204.MantleConvection
DS201112-0210
2011
Gottsman, J.Costa, A., Gottsman, J., Melnik, O., Sparks, R.S.J.A stress controlled mechanism for the intensity of very large magnitude explosive eruptions.Earth and Planetary Science Letters, Vol. 310, 1-2, pp. 161-166.MantleDyke fed eruptions - column collapse
DS201807-1510
2018
Gottsmann, J.H.Magee, C., Stevenson, C.T.E., Ebmeier, S.K., Keir, D., Hammond, J.O.S., Gottsmann, J.H., Whaler, K.A., Schofield, N., Jackson, C.A-L., Petronis, M.S., O'Driscoll, B., Morgan, J., Cruden, A., Vollgger, S.A., Dering, G., Micklethwaite, S., Jackson, M.D.Magma plumbing systems: a geophysical perspective. InSAR, GPS, GNSS, FWI, UAVsJournal of Petrology, in press available, 99p.Mantlemagmatism - geophysics

Abstract: Over the last few decades, significant advances in using geophysical techniques to image the structure of magma plumbing systems have enabled the identification of zones of melt accumulation, crystal mush development, and magma migration. Combining advanced geophysical observations with petrological and geochemical data has arguably revolutionised our understanding of, and afforded exciting new insights into, the development of entire magma plumbing systems. However, divisions between the scales and physical settings over which these geophysical, petrological, and geochemical methods are applied still remain. To characterise some of these differences and promote the benefits of further integration between these methodologies, we provide a review of geophysical techniques and discuss how they can be utilised to provide a structural context for and place physical limits on the chemical evolution of magma plumbing systems. For example, we examine how Interferometric Synthetic Aperture Radar (InSAR), coupled with Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) data, and seismicity may be used to track magma migration in near real-time. We also discuss how seismic imaging, gravimetry, and electromagnetic data can identify contemporary melt zones, magma reservoirs, and, or, crystal mushes. These techniques complement seismic reflection data and rock magnetic analyses that delimit the structure and emplacement of ancient magma plumbing systems. For each of these techniques, with the addition of full-waveform inversion (FWI), the use of Unmanned Aerial Vehicles (UAVs), and the integration of geophysics with numerical modelling, we discuss potential future directions. We show that approaching problems concerning magma plumbing systems from an integrated petrological, geochemical, and geophysical perspective will undoubtedly yield important scientific advances, providing exciting future opportunities for the volcanological community.
DS200912-0262
2008
Gotz, J.Gotz, J., Kempe, U.A comparison of optical microscope and scanning electron microscope based cathodluminesence (CL) imaging and spectroscopy applied to geosciences.Mineralogical Magazine, Vol. 72, 4, pp. 909-924.TechnologyCathodluminescence
DS1991-0592
1991
Gotze, H.J.Gotze, H.J., Monger, J.W.H.Global geoscience transects project: achievements and future goalsEpisodes, Vol. 14, No. 2, June pp. 131-138GlobalTectonics -General transects, Crust
DS1999-0172
1999
Gotze, H.J.Doring, J., Gotze, H.J.The isostatic state of the southern Urals crustGeol. Rundsch., Vol. 87, No. 4, Mar. pp. 500-10.Russia, UralsGeophysics - geodynamics, Tectonics
DS2001-0685
2001
Gotze, H.J.Li, X., Gotze, H.J.Ellipsoid, geoid, gravity, geodesy and geophysicsGeophysics, Vol. 6, No. 6, pp. 1660-68.GlobalGeophysics - not specific to diamonds, Overview
DS2002-0604
2002
Gotze, H.J.Gotze, H.J.,Krause, S.The Central Andean gravity high, a relic of an old subduction complex?Journal of South American Earth Sciences, Vol.14,8,March pp. 799-811.AndesTectonics - subduction
DS1990-0590
1990
Gotze, H-J.Gotze, H-J., Lahmeyer, B., Schmidt, S., Strunk, S., Araneda, M.Central Andes gravity dat a baseEos, Vol. 71, No. 16, April 17, pp. 401, 406-407Andes, Chile, ArgentinaGeophysics- gravity, Database
DS2003-0488
2003
Gotze, J.Gotze, J., Kempe., U.Cathodluminescence in the geosciencesNature, No. 6920, Jan. 16, pp. 221-222.GlobalTechniques - not specific to diamonds
DS200612-1427
2006
Gotze, J.Tichomirowa, M., Grosche, G., Gotze, J., Belyatsky, B.V., Savva, E.V., Keller, J., Todt, W.The mineral isotope composition of two Precambrian carbonatite complexes from the Kola Alkaline Province - alteration versus primary magmatic signatures.Lithos, In press available,Russia, Kola PeninsulaCarbonatite, geochronology, Tiksheozero, Siilinkarvi
DS201212-0729
2012
Gotze, J.Tichomirowa, M., Whitehouse, M., Gerdes, A., Gotze, J.Carbonatite metasomatism: evidence from geochemistry and isotope composition ( U-Pb, Hf, O) on zircons from two Precambrian carbonatites of the Kola alkaline province.Goldschmidt Conference 2012, abstract 1p.Russia, Kola Peninsula, ArchangelCarbonatite
DS201312-0329
2013
Gotze, J.Gotze, J.,Schertl, H-P.,Neurser, R.D., Kempe, U.Optical microscope cathodoluminesence (OM-CL) imaging as a powerful tool to reveal internal textures of minerals.Mineralogy and Petrology, Vol. 107, 3, pp. 373-392.TechnologySpectroscopy
DS201312-0636
2013
Gotze, J.Nasdala, L., Gotze, J., Hanchar, J.M.Luminescence spectroscopy and imaging: analytical advances and perspectives in the Earth Sciences and related disciplines.Mineralogy and Petrology, Vol. 107, 3, pp. 349-351.TechnologySpectroscopy
DS201312-0914
2013
Gotze, J.Tichomirowa, M., Whitehouse, M.J., Gerdes, A., Gotze, J., Schulz, B., Belyatsky, B.V.Different zircon recrystallization types in carbonatites caused by magma mixing: evidence from U-Pb dating, trace element and isotope composition ( Hf and O) of zircons from two Precambrian carbonatites from Fennoscandia.Chemical Geology, Vol. 353, pp. 173-198.Europe, Finland, SwedenCarbonatite
DS200512-1168
2005
Gou, F.Wang, Y., Fan, W., Peng, T., Zhang, H., Gou, F.Nature of the Mesozoic lithospheric mantle and tectonic decoupling beneath the Dabie Orogen, central China. Evidence from 40Ar 39Ar geochronology, Sr/Nd, PbChemical Geology, Vol. 220, 3-4, pp. 165-189.Asia, ChinaGeochronology - early Cretaceous mafic igneous rocks
DS201911-2555
2019
Gou, Z.Qiu, K., Yu, H., Wu, M., Geng, J., Ge, X., Gou, Z., Taylor, R.D.Discrete Zr and REE mineralization of the Baerzhe rare metal deposit, China.American Mineralogist, Vol. 104, pp. 1487-1502.ChinaREE

Abstract: Although REE (lanthanides + Sc + Y) mineralization in alkaline silicate systems is commonly accompanied with Zr mineralization worldwide, our understanding of the relationship between Zr and REE mineralization is still incomplete. The Baerzhe deposit in Northeastern China is a reservoir of REE, Nb, Zr, and Be linked to the formation of an Early Cretaceous, silica-saturated, alkaline intrusive complex. In this study, we use in situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of zircon and monazite crystals to constrain the relationship between Zr and REE mineralization at Baerzhe. Three groups of zircon are identified and are differentiated based upon textural observations and compositional characteristics. Type Ia zircons display well-developed oscillatory zoning. Type Ib zircons are darker in cathodoluminescence images and have more irregular zoning and resorption features than type Ia zircons. In addition, type Ib zircons can locally occur as overgrowths on type Ia zircons. Type II zircons contain irregular but translucent cores and rims with oscillatory zoning that are murky brown in color and occur in aggregates. Textural features and compositional data suggest that types Ia and Ib zircon crystallized at the magmatic stage, with type Ia being least-altered and type Ib being strongly altered. Type II zircons, on the other hand, precipitated during the magmatic to magmatichydrothermal transition. Whereas the magnitude of the Eu anomaly is moderate in the barren alkaline granite, both magmatic and deuteric zircon exhibit pronounced negative anomalies. Such features are difficult to explain exclusively by feldspar fractionation and could indicate the presence of fluid induced modification of the rocks. Monazite crystals occur mostly through replacement of zircon and sodic amphibole; monazite clusters are also present. Textural and compositional evidence suggests that monazite at Baerzhe is hydrothermal. Types Ia and Ib magmatic zircon yield 207Pb-corrected 206Pb/238U ages of 127.2 ± 1.3 and 125.4 ± 0.7 Ma, respectively. Type II deuteric zircon precipitated at 124.9 ± 0.6 Ma. The chronological data suggest that the magmatic stage of the highly evolved Baerzhe alkaline granite lasted less than two million years. Hydrothermal monazite records a REE mineralization event at 122.8 ± 0.6 Ma, approximately 1 or 2 million years after Zr mineralization. We therefore propose a model in which parental magmas of the Baerzhe pluton underwent extensive magmatic differentiation while residual melts interacted with aqueous hydrothermal fluids. Deuteric zircon precipitated from a hydrosilicate liquid, and subsequent REE mineralization, exemplified by hydrothermal monazite, correlates with hydrothermal metasomatic alteration that postdated the hydrosilicate liquid event. Such interplay between magmatic and hydrothermal processes resulted in the formation of discrete Zr and REE mineralization at Baerzhe.
DS1994-0644
1994
Gouchtchine, V.S.Gouchtchine, V.S., Ivanikov, V.V.Diamond potential in Quebec with modern theories on kimberlites, lamproites:comparison Belomar/Grenville.Preprint from Garde, 33p.Russia, West Virginia, Canada, OntarioDiamond genesis, Deposit -Belomar Grenville areas
DS200612-0875
2001
Gouda, H.C.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
DS200612-1267
2005
Gouda, H.C.Sharma, R., Muthry, Ch.V.V.S., Nagaraju, B.V., Gouda, H.C., Singh, R.K.Interpretation of aeromagnetic dat a of Panna and adjoining areas for evaluating of structural patterns favourable for emplacement of KCRs and depth magneticsGeological Society of India, Bangalore November Meeting Group Discussion on Kimberlites and Related Rocks India, Abstract p. 121-122.India, Madhya Pradesh, Aravalli Bundelkhand CratonGeophysics - magnetics
DS200812-1043
2008
Gouda, H.C.Sharma, R., Murthy, C.V.V.S., Mishra, V.P., Nagaraju, B.V., Gouda, H.C., Singh, R.K.Study of structural pattern through aeromagnetic dat a for mineral prospecting and kimberlite clan rocks in an area around Mahbubnagar, A.P.Journal of the Geological Society of India, Vol. 72, 2, pp. 175-189.IndiaGeophysics - magnetics
DS202102-0228
2021
Goudie, A.M.Viles, H.A., Goudie, A.S., Goudie, A.M.Ants as geomorphological agents: a global assessment.Earth-Science Reviews, Vol. 213, doi.org/10.1016/j.earscirev.2020.103469 17p. PdfGlobalgeomorphology

Abstract: Ants are abundant in most of the world's terrestrial environments. They are energetic, strong for their size, numerous, and socially cooperative. They play many geomorphologically important roles. In particular, they construct mounds and subterranean galleries, create patterned ground, play a role in bioturbation, affect vegetation cover and soil properties (such as infiltration rate) and influence runoff and erosion. They also play roles in biogeochemical cycling and rock and mineral weathering. Here, we review and reanalyse data collected from over 80 studies on ant contributions to geomorphology from around the world. The clearest manifestation of the geomorphological role of ants is found in their various constructions, such as mounds. There can be hundreds or thousands of mounds per hectare, with a median density of 125 ha?1 recorded in the studies reviewed. The longevity of these features varies and some are stable while others are highly erodible. The construction of mounds and galleries causes bioturbation (pedoturbation), a role which ants share with termites, worms and many mammals. A median rate of 1.5 t ha?1 a?1 is derived from the studies reviewed. Ants also produce patterned ground through their effects on vegetation. The relationships between ant activity and runoff and erosion are complex and not consistent. Bioturbation of soil, tunnelling activity, the construction of underground chambers, galleries and macro-pores, the removal and/or accumulation of organic material, and changes in vegetation cover, are all mechanisms by which ants might modify soil infiltration characteristics. Because of their effect on soil infiltration rates, sediment provision and on vegetation cover, ants can have a profound influence on runoff and soil movement on slopes. Only a modest amount of work has been done to investigate the role that ants play in rock weathering. Ants are greatly affected by human activities (especially land cover changes), and some geomorphologically-active species have proved to be highly invasive. The response of ants to future climate changes needs further investigation.
DS1989-0529
1989
Goudie, A.S.Goudie, A.S.Salt tectonics and geomorphologyProgress in Physical Geography, Vol. 13, No. 4, pp. 597-605GlobalSalt tectonics, Evaporites
DS1995-0664
1995
Goudie, A.S.Goudie, A.S., Wells, G.L.The nature, distribution and formation of pans in arid zonesEarth Science Reviews, Vol. 38, pp. 1-69.Zimbabwe, South Africa, Namibia, United States, ArgentinaPan distribution -review, Weathering processes
DS1995-0665
1995
Goudie, A.S.Goudie, A.S., Wells, G.L.The nature, distribution and formation of pans in arid zonesEarth Science Reviews, Vol. 38, pp. 1-69Zimbabwe, South Africa, Namibia, United States, Argentina, GlobalPans - depressions, classification, Overview - fluvial processes, weathering, deflation
DS200712-1120
2007
Goudie, A.S.Viles, H.A., Goudie, A.S.Rapid salt weathering in the coastal Namib desert: implications for Lands cape development.Geomorphology, Vol. 85, 1-2, March 15, pp. 49-62.Africa, NamibiaGeomorphology - not specific to diamonds
DS202102-0228
2021
Goudie, A.S.Viles, H.A., Goudie, A.S., Goudie, A.M.Ants as geomorphological agents: a global assessment.Earth-Science Reviews, Vol. 213, doi.org/10.1016/j.earscirev.2020.103469 17p. PdfGlobalgeomorphology

Abstract: Ants are abundant in most of the world's terrestrial environments. They are energetic, strong for their size, numerous, and socially cooperative. They play many geomorphologically important roles. In particular, they construct mounds and subterranean galleries, create patterned ground, play a role in bioturbation, affect vegetation cover and soil properties (such as infiltration rate) and influence runoff and erosion. They also play roles in biogeochemical cycling and rock and mineral weathering. Here, we review and reanalyse data collected from over 80 studies on ant contributions to geomorphology from around the world. The clearest manifestation of the geomorphological role of ants is found in their various constructions, such as mounds. There can be hundreds or thousands of mounds per hectare, with a median density of 125 ha?1 recorded in the studies reviewed. The longevity of these features varies and some are stable while others are highly erodible. The construction of mounds and galleries causes bioturbation (pedoturbation), a role which ants share with termites, worms and many mammals. A median rate of 1.5 t ha?1 a?1 is derived from the studies reviewed. Ants also produce patterned ground through their effects on vegetation. The relationships between ant activity and runoff and erosion are complex and not consistent. Bioturbation of soil, tunnelling activity, the construction of underground chambers, galleries and macro-pores, the removal and/or accumulation of organic material, and changes in vegetation cover, are all mechanisms by which ants might modify soil infiltration characteristics. Because of their effect on soil infiltration rates, sediment provision and on vegetation cover, ants can have a profound influence on runoff and soil movement on slopes. Only a modest amount of work has been done to investigate the role that ants play in rock weathering. Ants are greatly affected by human activities (especially land cover changes), and some geomorphologically-active species have proved to be highly invasive. The response of ants to future climate changes needs further investigation.
DS1960-0454
1964
Gough, D.I.Gough, D.I., Brock, A.The Paleomagnetism of the Shawa IjoliteJournal of Geophysical Research, Vol. 69, No. 12, PP. 2489-2493.ZimbabweGeology, Related Rocks
DS1960-0455
1964
Gough, D.I.Gough, D.I., Brock, A.The Paleomagnetism of the Ring Complexes at Marangudzi and The Mateke Hills.Journal of Geophysical Research, Vol. 69, No. 12, PP. 2499-2507.ZimbabweGeology, Related Rocks
DS1970-0044
1970
Gough, D.I.Camfield, P.A., Gough, D.I., Porath, H.Magnetometer Array Studies in the Northwestern United States and Southwestern Canada.Geophys. Journal of Res. Astron. Soc., Vol. 22, No. 2, PP. 201-221.Montana, South Dakota, North DakotaGeophysics, Mid-continent
DS1970-0178
1970
Gough, D.I.Porath, H., Oldenburg, D.W., Gough, D.I.Seperation of Magnetic Variation Fields and Conductive Structures in the Western United States.Geophys. Journal of Res. Astron. Soc., Vol. 19, No. 3, PP. 237-260.GlobalGeophysics, Mid-continent
DS1970-0183
1970
Gough, D.I.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
DS1970-0388
1971
Gough, D.I.Porath, H., Gough, D.I.Mantle Conductive Structures in the Western United States from magnetometer Array Studies.Roy. Astron. Soc. Geophys. Journal, Vol. 23, No. 4, PP. 387-398.GlobalGeophysics, Mid-continent
DS1970-0696
1973
Gough, D.I.Gough, D.I., De beer, J.H., Van zijl, J.S.V.A Magnetometer Array Study in Southern AfricaRoy. Astron. Soc. Geophys. Journal, Vol. 34, PP. 421-433.South Africa, BotswanaGeophysics
DS1975-0003
1975
Gough, D.I.Alabi, A.O., Camfield, P.A., Gough, D.I.The North American Central Plains Conductive AnomalyGeophys. Journal of Res. Astron. Soc., Vol. 43, PP. 815-833.GlobalGeophysics, Mid-continent
DS1975-0064
1975
Gough, D.I.De beer, J.H., Gough, D.I., Van Zijl, J.S.V.An Electrical Conductivity Anomaly and Rifting in Southern Africa. #1Nature., Vol. 225, PP. 678-680.South Africa, BotswanaGeophysics, Tectonics
DS1975-0065
1975
Gough, D.I.De beer, J.H., Gough, D.I., Van Zyjl, J.S.V.An Electrical Conductivity Anomaly and Rifting in Southern Africa. #2Nature., Vol. 255, JUNE 26TH, PP. 678-680.BotswanaGeotectonics, Geophysics
DS1980-0104
1980
Gough, D.I.De beer, J.H., Gough, D.I.Conductive Structures in Southern Most Africa. a Magnetometer Array Study.Roy. Astron. Soc. Geophys. Journal, Vol. 63, No. 2, PP. 479-495.South Africa, BotswanaTectonics, Geophysics
DS1983-0259
1983
Gough, D.I.Gough, D.I.Electromagnetic Geophysics and Global TectonicsJournal of Geophysical Research, Vol. 88. No. B4, APRIL 10, PP. 3367-3377.South Africa, United StatesMid-continent, Geophysics
DS1989-0530
1989
Gough, D.I.Gough, D.I.Geophysical features and the lower continental crustGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A101. (abstract.)OntarioTectonics, Kapuskasing Lithoprobe
DS1992-0591
1992
Gough, D.I.Gough, D.I.Electromagnetic exploration for fluids in the earth's crustEarth Science Reviews, Vol. 32, pp. 3-18GlobalGeophysics, Electromagnetics
DS1992-0803
1992
Gough, D.I.Jones, A.G., Gough, D.I., Kurtz, R.D., De Laurier, J.M., et al.Electromagnetic images of regional structure in the southern CanadianCordilleraGeophysical Research Letters, Vol. 12, No. 24, pp. 2373-2376Cordillera, British ColumbiaGeophysics -electromagnetic, Tectonics, structure
DS1993-0959
1993
Gough, D.I.Majorowicz, J.A., Gough, D.I., Lewis, T.J.Electrical conductivity and temperature in the Canadian Cordilleran crustEarth and Planetary Science Letters, Vol. 115, No. 1-4, March pp. 57-64.British Columbia, AlbertaGeophysics, Heat flow
DS1994-1091
1994
Gough, D.I.Majorowicz, J.A., Gough, D.I.A model of crustal conductive structure in the Canadian CordilleraGeophysical Journal International, Vol. 117, pp. 301-312.British ColumbiaGeophysics, Magnetotellurics
DS1993-0563
1993
Gough, L.P.Gough, L.P.Understanding our fragile environment: lessons from geochemical studiesUnited States Geological Survey (USGS) Circular, No. 1105, 34pUnited StatesBook -ad, Environment -geochemistry
DS201804-0694
2017
Gouiza, M.Gouiza, M., Bertotti, G., Andriessen, P.A.M.Mesozoic and Cenozoic thermal history of the Western Reguibat Shield ( West African Craton).Terra Nova, pp. 135-145.Africa, Moroccogeothermometry

Abstract: Using low?temperature thermochronology on apatite and zircon crystals, we show that the western Reguibat Shield, located in the northern part of the West African Craton, experienced significant cooling and heating events between Jurassic and present times. The obtained apatite fission track ages range between 49 and 102 Ma with mean track lengths varying between 11.6 and 13.3 ?m and Dpar values between 1.69 and 3.08 ?m. Zircon fission track analysis yielded two ages of 159 and 118 Ma. Apatite (U-Th)/He uncorrected single?grain ages range between 76 and 95 Ma. Thermal inverse modelling indicates that the Reguibat Shield was exhumed during the Early Cretaceous, Late Cretaceous, Palaeocene-Eocene and Quaternary. These exhumation events were coeval with regional tectonic and geodynamic events, and were probably driven by a combined effect of plate tectonics and mantle dynamics.
DS1992-0592
1992
Goulard, M.Goulard, M., Voltz, M.Linear co regionalization model: tools for estimation and choice of cross-variogram matrixMath. Geol, Vol. 24, No. 3, April pp. 269-286GlobalGeostatistics, Cross-variograM.
DS201607-1349
2016
Goulart, R.Goulart, R.Depositional evolution of southwest Gondwana Neoproterozoic paleobasins based on Sr, C and O isotopic compositions of carbonatic rocks from the Sul-Riograndense shield, Brazil.IGC 35th., Session A Dynamic Earth 1p. AbstractSouth America, BrazilCarbonatite
DS200712-0084
2006
GouldBlowes, 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
DS1991-0593
1991
Gould, C.C.Gould, C.C., Pearce, K.Informatiuon needs in the sciences: an assessmentResearch Libraries, Mountain View, 79p. Cost?GlobalInformation, Sciences
DS1920-0155
1923
Gould, C.N.Gould, C.N.Crystalline Rocks of the PlainsGeological Society of America (GSA) Bulletin., Vol. 34, PP. 54-55.United States, Kansas, Central States, WilsonBlank
DS1975-0717
1978
Gould, D.Coates, J.N.M., Davies, J., Gould, D., Hutchins, D.G., Jones, C.The Kalatraverse One ReportBotswana Geological Survey, Bulletin. No. 21, 421P.Botswana, South AfricaGeology, Regional Tectonics
DS200812-0073
2008
Gould, D.Bailey, B.L., Smith, L., Neuner, M., Gupton, M., Blowes, D.W., Smith, L., Sego, D.C., Gould, D.Diavik waste rock project: early stage geochemistry and microbiology of effluent from low sulfide content waste rock piles.Northwest Territories Geoscience Office, p. 11-12. abstractCanada, Northwest TerritoriesDeposit - Diavik
DS1985-0241
1985
Gould, D.I.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
DS1992-0593
1992
Gould, I.Gould, I.Australia's loss is other's gainAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 2, April, pp. 31-33AustraliaOverview of exploration, Economics
DS1993-0564
1993
Gould, I.G.Gould, I.G.An industry perspective on research needs in the mining industryAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 2, April pp. 80-86AustraliaEconomics, Mining -philosophy
DS1995-0666
1995
Gould, I.G.Gould, I.G.Foreign investment in the mineral resources industry in developingcountriesWorld Mining Congress, Institute International Research held May, 15pAsiaEconomics -investment, CRA.
DS1996-0550
1996
Gould, I.G.Gould, I.G.The omniscient explorationist - a hazard to prosperityAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No 3, May pp. 27-30AustraliaEconomics, Geological thinking
DS1996-0551
1996
Gould, I.G.Gould, I.G.Symbiosis in mineral explorationAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 8, Dec. pp. 33-36AustraliaExploration -philosophy
DS200812-0763
2008
Gould, W.D.Moore, M.L., Blowes, D.W., Ptacek, C.J., Gould, W.D., Smith, L.,Sego, D.Humidity cell analysis of waste rock from the Diavik diamond mine NWT, Canada.Goldschmidt Conference 2008, Abstract p.A647.Canada, Northwest TerritoriesDeposit - Diavik
DS200512-0357
2005
Goulden, J.Goulden, J.Worldwide exploration budgets continue to rise: a 2004 review. Gold, late stage exploration, juniors,Mining Journal Exploration Special, March 2005 pp.12-14.News item - brief overview
DS200712-0376
2007
Goulden, J.Goulden, J.World exploration trends.Mining Journal Exploration Special, pp. 2-5.GlobalEconomics - exploration trends
DS200912-0263
2009
Goulden, J.Goulden, J., Metals Economics GroupExploration record... the total amount spent on nonferrous exploration in 2008 was an all time high.Mining Journal Exploration Special, pp. 9-12.GlobalExploration expenditures
DS201012-0246
2010
Goulden, J.Goulden, J.Exploration expenditure targeted.Mining Journal Exploration Special, March pp. 20-24.GlobalEconomics
DS1989-0915
1989
Goulet, C.Machado, N., Goulet, C., Gariepy, C.uranium-lead (U-Pb) geochronology of reactivated Archean basement and Hudsonian metamorphism in northern Labrador Trough.Canadian Journal of Earth Sciences, Vol. 26, pp. 1-15.Quebec, Ungava, LabradorGeochronology, Tectonics
DS1989-0916
1989
Goulet, N.Machado, N., Goulet, N., Gariepy, C.uranium-lead (U-Pb) geochronology of reactivated Archean basement and of Hudsonian metamorphism in the northern Labrador...Canadian Journal of Earth Sciences, Vol. 26, pp. 1-15.Labrador, QuebecGeochronology, Labrador Trough
DS1989-0917
1989
Goulet, N.Machado, N., Goulet, N., Gariepy, C.uranium-lead (U-Pb) (U-Pb) geochronology of reactivated Archean basement and ofHudsonian metamorphism in the northern Labrador TroughCanadian Journal of Earth Sciences, Vol. 26, No. 1, January pp. 1-15Quebec, Labrador, UngavaProterozoic, Geochronology
DS1996-0365
1996
Goulet, N.Digonnet, S., Goulet, N., Bourne, J.H., Stevenson, R.Genesis and comparison of kimberlite dykes from the Ungava Bay area, north Quebec and from West GreenlandLithoprobe Report, No. 57, pp. 38-43.Quebec, Ungava, Labrador, GreenlandDike - geochemistry
DS1996-0366
1996
Goulet, N.Digonnet. S., Goulet, N., Bourne, J., Stevenson, R.Modele de mise en place des kimberlites diamantiferes dans les Torngats:Nouveau Quebec.Quebec Information Seminar, DV 96-02, p. 18.Quebec, Ungava, LabradorKimberlite - genesis, Torngat Mountains
DS1997-0710
1997
Goulet, N.Machado, N., Clark, T., David, J., Goulet, N.uranium-lead (U-Pb) ages for magmatism and deformation in the New Quebec OrogenCanadian Journal of Earth Sciences, Vol. 34, pp. 716-23.Quebec, Labrador, UngavaMagmatism, Orogeny - New Quebec
DS1998-0349
1998
Goulet, N.Digonnet, S., Bourne, J., Goulet, N.Chimie crystalline de grenats and radite et implication dans la petrogenesedes kimberlites d'abloviak.University of Quebec, pp. 68-72Quebec, Ungava, LabradorDike - geochemistry
DS2000-0232
2000
Goulet, N.Digonnet, S., Goulet, N., Bourne, Stevenson, ArchibaldPetrology of the Abloviak aillikite dykes, New Quebec: evidence for Cambrian Diamondiferous alkaline provinceCanadian Journal of Earth Sciences, Vol. 37, No. 4, Apr. pp. 517-33.Quebec, Labrador, UngavaMineral chemistry - analyses, petrography, age, Geochronology, tectonics
DS2000-0233
2000
Goulet, N.Digonnet, S., Goulet, N., Stevenson, R.Petrology of the aillikite dikes, Abloviak: new exploration target and evidence for Cambrian diamond...Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Calgary May 2000, 4p.Quebec, Ungava, Labrador, GreenlandDiamondiferous province northeastern America, Mafic dykes - Abloviak
DS2003-0489
2003
Goulet, N.Goulet, N., Caderon, S., Houle, P.Cr uvarovite garnet in Archean ophiolite Abitib greenstone belt: implications forGeological Association of Canada Annual Meeting, Poster Abstract onlyQuebecMineralogy
DS200412-0701
2003
Goulet, N.Goulet, N., Caderon, S., Houle, P.Cr uvarovite garnet in Archean ophiolite Abitib greenstone belt: implications for diamond and Ni Co mineralisations in the CummiGeological Association of Canada Annual Meeting, Poster Abstract onlyCanada, QuebecMineralogy
DS1994-0645
1994
Goulevich, J.Goulevich, J., Eupene, G.S.Geoscience rating for valuation of exploration properties - applicability of Kilburn method...examplesValmin 94, pp. 175-189AustraliaEconomics, Ore reserves -valuation
DS1991-0594
1991
Goulevitch, J.Goulevitch, J.Valuation of mineral exploration properties without identified resources -aview from the fieldAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 7, December pp. 40-46GlobalEconomics, Valuation, ore reserves, geostatistics
DS1985-0242
1985
Gourgaud, A.Gourgaud, A.Mixture of magmas in the alkaline and calc-alkaline series:their role In the genesis of intermediate lavas and their influence on plutonicmechanisms.Annales Scientif. de l'universite de Clermont (in French), Vol. 86, 52ppGlobalBurgos Diamant Fissue
DS200512-0009
2005
Gourgaud, A.Aldanmaz, E., Gourgaud, A., Kaymakc, N.Constraints on the composition and thermal structure of the upper mantle under NW Turkey: evidence from mantle xenoliths and alkali primary melts.Journal of Geodynamics, Vol. 39,3, April pp. 277-316.Europe, TurkeySpinel-lherzolites, geothermometry, xenoliths upper mantle
DS201212-0014
2012
Gouriet, K.Amodeo, J., Carrez, Ph., Cordier, P., Gouriet, K., Kraych, A.Modelling dislocation and plasticity in MgO and MgSiO3 perovskite under lower mantle conditions.emc2012 @ uni-frankfurt.de, 1p. AbstractMantlePerovskite
DS1859-0014
1785
Gourjon, M.Gourjon, M.The Indian Connoisseur or the Nature of Precious StonesLondon: , IndiaHistory
DS1995-0667
1995
Gourley, A.Gourley, A.Valuating mineral royalties: the risks and returnsPreprint from Insight Conf, May 25, 51pCanadaEconomics, Royalties
DS1995-0668
1995
Gourley, A.Gourley, A.Valuating mineral royalties: the risks and returnsInsight: Financing options for the minerals industry, 51p.Canada, GlobalEconomics, Mineral royalties -not specific to diamonds
DS1996-0552
1996
Gourley, A.Gourley, A.Mining agreements: from a North American major mining company perspective #1Prospectors and Developers Association of Canada (PDAC) Short Course for, pp. 131-148GlobalMining economics, Short course notes
DS2003-0490
2003
Gourley, A.Gourley, A.Contractual faults and the discounting of mineral royaltiesPreprint from author - presentation at MES Symposium, Jan 20, 30p.GlobalMineral royalty - legal
DS1993-0565
1993
Gourley, A.C.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
DS1998-0525
1998
Gourley, A.C.Gourley, A.C.Mining agreements: from a North American major mining company perspective #2Prospectors and Developers Association of Canada (PDAC) Fundamentals of, pp. 125-138GlobalMineral exploration, Legal - mining agreements
DS200912-0053
2009
Gourmelen, N.Biggs, J., Amelung, F., Gourmelen, N., Dixon, T.H.,Kim, S-W.InSAR observations of 2007 Tanzania rifting episode reveal mixed fault and dyke extension in an immature continental rift.Geophysical Journal International, Vol. 179, 1, pp. 549-558.Africa, TanzaniaGeophysics - seismics
DS1998-1146
1998
GoussevPeirce, J.W., Goussev, Charters, Abercrombie, De PaoliIntrasedimentary magnetization by vertical fluid flow and exotic geochemistry.Leading Edge, Vol. 17, No. 1, pp. 89-92.Alberta, Western CanadaGeophysics - magnetics, Basin
DS201705-0832
2017
Goussi Ngalamo, J.F.Goussi Ngalamo, J.F., Bisso, D., Abdelsalam, M.G., Atekwana, E.A., Katumwehe, A.B., Ekodeck, G.E.Geophysical imaging of metacratonization in the northern edge of the Congo craton in Cameroon.Journal of African Earth Sciences, Vol. 129, pp. 94-107.Africa, CameroonCraton, Congo

Abstract: We used the World Gravity Map (WGM 2012) data to investigate the Archean Congo craton and the Oubanguides orogenic belt in Cameroon. The Oubanguides orogenic belt constitutes, from northwest to southeast, the Neoproterozoic West Cameroon domain, the Paleoproterozoic-Neoproterozoic Adamawa-Yade domain, and the dominantly Neoproterozoic Yaoundé domain (the crustal expression of the suture zone between the Congo craton and the orogenic terranes). We analyzed the WGM 2012 data to identify different gravity anomalies. We also applied the two-dimensional (2D) radially-averaged power spectral analysis to the WGM 2012 data to estimate the Moho depth. Additionally, we developed a 2D forward gravity model along a Nsbnd S profile to image the lithospheric structure of the Precambrian entities. We found that: (1) the Congo craton, the Yaoundé domain, the southeastern part of the West Cameroon domain, and the northern part of the Adamawa-Yade domain are characterized by low gravity anomaly. (2) the southern part of the Adamawa-Yade domain is marked by a pronounced E-W trending high gravity anomaly. (3) the crust is thicker beneath the Congo craton, the Yaoundé domain and the southern part of the Adamawa-Yade domain. (4) the presence of a denser lower crust material beneath the southern part of the Adamawa-Yade domain. We propose that this denser crustal material is an under-thrusted portion of the Congo craton that has been densified through metacratonization processes that accompanied collision between the craton and the orogenic terranes. This is in good agreement with geological and geochemical observations indicating that the northern edge of the Congo craton and the Adamawa-Yade domain had undergone metacratonization during the Neoproterozoic. Our suggestion is also in good agreement with observations which show that the margins of many cratons worldwide have been decratonized due to subduction processes. Our work highlights the importance of potential field geophysical data in mapping the metacratonized margins of cratons.
DS201812-2812
2018
Goussi Ngalamo, J.F.Goussi Ngalamo, J.F., Sobh, M., Bisso, D., Abdelsalam, M.G., Atekwana, E., Ekodeck, G.E.Lithospheric structure beneath the central Africa orogenic belt in Cameroon from the analysis of satellite gravity and passive seismic data.Tectonophysics, Vol. 745, pp. 326-337.Africa, Cameroongeophysics - seismics

Abstract: We present original results that contribute to the understanding of lithospheric structures modification of regions that have witnessed superimposition of multiple tectonic events throughout their geological history. We analyze satellite gravity data through two-dimensional radially-averaged power spectral analysis as well as passive seismic data through thermal modeling to image the depth to the Moho and the lithosphere - asthenosphere boundary (LAB beneath the Central Africa Orogenic Belt (CAOB). The CAOB is an ENE-trending deformation belt extending from Cameroon in the west to Sudan in the east. In Cameroon, it is found on the northern edge of the Congo craton represented by the Oubanguides orogenic belt (the Western Cameroon, the Adamawa - Yade, and the Yaoundé domains). It coincides with the Adamawa plateau and the Benue Trough, and it is spotted by the Cenozoic Cameroon Volcanic Line (CVL). The CAOB was formed during the Precambrian Greater Gondwana assembly but was reactivated during the Mesozoic as a result of Gondwana breakup. We find deeper Moho and LAB) beneath Congo craton and the Yaoundé domain reaching ~50?km and ~200?km, respectively. We map shallower Moho and LAB beneath the CAOB (together with the Adamawa plateau and the Benue trough) reaching ~25?km and ~70?km, respectively. We interpret the shallower LAB beneath the CAOB as due to zonal sub-continental lithospheric mantle (SCLM) delamination along the northern edge of the Congo craton that occurred in association with collisional assembly of Greater Gondwana. This allowed for channelization of mantle flow during the Cenozoic resulting in the formation of the CVL and the uplift of the Adamawa plateau. Our approach can be used to understand the modification of lithospheric structures beneath other terrains that have long tectonic history.
DS200612-0484
2006
Goutham, M.R.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
DS1998-0526
1998
Goutier, J.Goutier, J., Doucet, P., Dion, C., Beausoleil, C.Geologie de la region du lac Esprit (SNRC 33F05)Quebec Department of Mines, RG 98-09, 39p.QuebecGeology
DS1998-0527
1998
Goutier, J.Goutier, J., Doucet, P., Dion, C., Beausoleil, C.Geologie de la region du lac Kowskatehkakmow (SNRC 33F06)Quebec Department of Mines, RG 98-16, 48p.QuebecGeology
DS2001-0440
2001
Goutier, J.Hamilton, M.A., Goutier, J., Matthews, W.uranium-lead (U-Pb) baddeleyite age for the Paleoproterozoic Lac Esprit dyke swarm, James Bay region, Quebec.Geological Survey of Canada (GSC) Current Research, No. 2001-F5, 17p.Quebec, James Bay LowlandsGeochronology, Yasinski Lake, dike swarm
DS200712-0120
2007
Goutier, J.Buchan, K.L., Goutier, J., Hamilton, M.A., Ernst, R.E., Matthews, W.A.Paleomagnetism, U Pb geochronology and geochemistry of Lac Esprit and other dyke swarms, James Bay area, Quebec: implications for Paleoproterozoic deformationCanadian Journal of Earth Sciences, Vol. 44, 5, pp. 643-664.Canada, QuebecDyke swarms
DS200712-0377
2007
Goutorbe, B.Goutorbe, B., Drab, L., Loubet, N., Lucazeau, F.Heat flow of the eastern Canadian rifted continental margin revisited.Terra Nova, Vol. 19, 6, pp. 381-386.CanadaGeothermometry
DS200812-0424
2008
Goutorbe, B.Goutorbe, B., Lucazeau, F., Bonneville, A.The thermal regime of South African continental margins.Earth and Planetary Science Letters, Vol. 267, 1-2, pp.256-265.Africa, South AfricaGeothermometry
DS202111-1769
2019
Gouvea, Y.Gouvea, Y., Stehmann, J.Solanum adamantium, a new narrowly endemic species from a diamondiferous region of the Espinhaco Range in Minas Gerais, Brazil.Systematic Botany, Vol. 44, 4, pp. 923-929. pdfSouth America, Brazilbotany

Abstract: Solanum adamantium is described from Serra de Grão Mogol, located in the Espinhaço range, in northern Minas Gerais State, Brazil. The new species is ecologically and morphologically similar to the prickly species S. buddleiifolium and S. thomasiifolium, from which it differs in a series of vegetative and reproductive characters. We discuss the morphological similarities and differences among these species, as well as certain aspects of the new taxon's ecology and geographic distribution. Images of diagnostic characters, a map of geographical distribution, a preliminary conservation assessment, and full specimen citations are provided.
DS201112-0383
2010
Gouveau Vasconcellos, E.M.Gouveau Vasconcellos, E.M., Dos Reis Neto, J.M.Caracterizacao morfologica de cristais de diamante do Rio Tibagi, municipio de Telemaco Borba, Parana.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 34-35.South America, Brazil, ParanaDiamond morphology
DS201112-0256
2011
Gouveia de OliveiraDe Oliveira Cordeiro, Brod, Palmieri, Gouveia de Oliveira, Soares Rocha Barbosa, Santos, Gaspar, AssisThe Catalao I niobium deposit, central Brazil: resources, geology and pyrochlore chemistry.Ore Geology Reviews, Vol. 41, pp. 112-121.South America, BrazilCarbonatite
DS201112-0257
2011
Gouveia de Oliveira, C.De Oliveire Cordeiro, P.F., Brod, J.A., Ventura Santos, R., Dantas, E.L., Gouveia de Oliveira, C., Soares Rochas Barbosa, E.Stable (C,O) and radiogenic (Sr,Nd) isotopes of carbonates as indicators of magmatic and post-magmatic processes of phoscorite series rocks and carbonatites from Catalao 1, central Brazil.Contributions to Mineralogy and Petrology, Vol. 161, 3, pp. 451-464.South America, BrazilCarbonatite
DS201012-0144
2010
Gouvieia de Oliveira, C.De Oliveira Cordeiro, P.F., Brod, J.A., Ventura Santos, R., Dantas, E.L., Gouvieia de Oliveira, C., Soares Rocha, Barbosa, E.Stable ( C,O) and radiogenic (Sr, Nd) isotopes of carbonates as indicators of magmatic and post magmatic processes of phoscorite series rocks and carbonatites fContributions to Mineralogy and Petrology, In press available, 14p.South America, BrazilCatalao I
DS201709-1962
2017
Gouy, S.Borisova, A.Y., Zagrtdenov, N.R., Toplis, M.J., Bohrson, W.A., Nedelec, A., Safonov, O.G., Pokrovski, G.S., Ceileneer, G., Melnik, O.E., Bychkov, A.Y., Gurenko, A.A., Shscheka, S., Terehin, A., Polukeev, V.M., Varlamov, D.A., Gouy, S., De Parseval, P.Making Earth's continental crust from serpentinite and basalt. Goldschmidt Conference, abstract 1p.Mantleperidotites

Abstract: How the Earth's continental crust was formed in the Hadean eon is a subject of considerable debates [1-4]. For example, shallow hydrous peridotites [2,5], in particular the Hadean Earth's serpentinites [6], are potentially important ingredients in the creation of the continental ptoto-crust, but the mechanisms of this formation remain elusive. In this work, experiments to explore serpentinite-basalt interaction under conditions of the Hadean Earth were conducted. Kinetic runs lasting 0.5 to 48 hours at 0.2 to 1.0 GPa and 1250 to 1300°C reveal dehydration of serpentinite and release of a Si-Al-Na-K-rich aqueous fluid. For the first time, generation of heterogeneous hydrous silicic melts (56 to 67 wt% SiO2) in response to the fluid-assisted fertilisation and the subsequent partial melting of the dehydrated serpentinite has been discovered. The melts produced at 0.2 GPa have compositions similar to those of the bulk continental crust [2,3]. These new findings imply that the Earth's sialic proto-crust may be generated via fluid-assisted melting of serpentinized peridotite at shallow depths (?7 km) that do not require plate subduction during the Hadean eon. Shallow serpentinite dehydration and melting may be the principal physico-chemical processes affecting the earliest lithosphere. Making Earth's continental crust from serpentinite and basalt.
DS201906-1296
2019
Gouza, M.Gouza, M., Paton, D.A.The role of inherited lithospheric heterogeneities in defining the crustal architecture of rifted margins and the magmatic budget during continental breakup.Geochemistry, Geophysics, Geosystems, Vol. 20, 4, pp. 1836-1853.Mantlemagmatism

Abstract: During the final stage of continental rifting, stretching localizes in the future distal domain where lithospheric necking occurs resulting in continental breakup. In magma?poor margins, the lithospheric necking is accompanied by crustal hyperextension, serpentinization, and exhumation of mantle lithosphere in the continent?ocean transition domain. In magma?rich margins, the necking is accomplished by the emplacement of large amounts of volcanics in the continental?ocean transition, in the form of seaward dipping wedges of flood basalts (seaward dipping reflections). This study examines the factors controlling the final crustal architecture observed in rifted margins and the magmatic budget during continental breakup, using observations from the Labrador Sea. The latter shows magma?rich breakup with seaward dipping reflections documented in the north and magma?poor breakup with a wide domain of exhumed serpentinized mantle recorded in the south. The pre?rift strength of the lithosphere, defined by the inherited thermal structure, composition, and thickness of the lithospheric layers, controls the structural evolution during rifting. While variations in the magmatic budget associated with breakup are controlled primarily by the interaction between the pre?rift inheritance, the timing and the degree of mantle melting, in relation to lithospheric thinning and mantle hydration.
DS200812-0425
2008
Government of IndiaGovernment of IndiaLok Sabha .... Exploration of Mines of high value minerals during 10th plan.Government of India, October 21, 1/4p.India, Andhra PradeshNews item - kimberlite pipes
DS200412-0702
2004
Government of Northwest TerritoriesGovernment of Northwest Territories2004 diamond industry report.. diamond facts.Government of Northwest Territories, June 25p.Canada, Northwest TerritoriesNews item - diamond production, pipeline, industry
DS1991-0375
1991
Government of theDepartment of Energy, Mines and Petroleum Resources, Government of theA guide to legislation affecting exploration and mining in the NorthwestTerritoriesDepartment of Energy, Mines and Petroleum Resources, Government of the, Approx. 150pNorthwest TerritoriesLegal, Legislation, Mining
DS2003-0491
2003
Government of the Northwest Territories and Quebec Ministere des resourcesGovernment of the Northwest Territories and Quebec Ministere des resourcesTowards a national diamond strategyGnwt And Quebec, Sept. 76p.Northwest Territories, Quebec, CanadaGeneral information, life cycle, issues, opportunities
DS200412-0703
2003
Government of the Northwest Territories and Quebec Ministere des resources naturellesGovernment of the Northwest Territories and Quebec Ministere des resources naturellesTowards a national diamond strategy.GNWT and Quebec, Sept. 76p.Canada, Northwest Territories, QuebecGeneral information, life cycle, issues, opportunities
DS1860-0373
1882
Government PrinterGovernment PrinterReport of the Select Committee on Illicit Diamond BuyingCape Town: Cape of Good Hope Government Printer., Africa, South Africa, Cape ProvinceLegal
DS1860-0374
1882
Government PrinterGovernment PrinterReport by the Inspector of Diamond Mines in the Late Province of Griqualand West for the Year 1881.Cape Town Parliament Report., No. G27-82, 33P.Africa, South Africa, Cape ProvinceMining engineering
DS1860-0398
1883
Government PrinterGovernment PrinterReports by the Inspector of Diamond Mines in the Late Province of Griqualand West for the Year 1882.Cape Town Parliament Report., No. G34-83, 36P.Africa, South Africa, Cape ProvinceMining engineering
DS1860-0452
1885
Government PrinterGovernment PrinterOur Diamond Industry #2Kimberley: The Board For The Protection of Mining Interests, 109P.Africa, South AfricaLegal
DS1860-0453
1885
Government PrinterGovernment PrinterOur Diamond Industry #1Kimberley: Radford And Roper., 109P.Africa, South Africa, Cape ProvinceEconomics
DS1860-0484
1886
Government PrinterGovernment PrinterFurther Returns Showing Imports of Diamond into and ExportsKimberley: The Board For The Protection of Mining Interest., 13P.Africa, South AfricaHistory, Legal
DS1860-0491
1886
Government PrinterGovernment PrinterHandbook of North Carolin a With Map of the StateRaleigh: P.M. Hale, State Printer., 352P.United States, North Carolina, AppalachiaDiamond Occurrence
DS1860-0579
1888
Government PrinterGovernment PrinterReturns Showing Imports of Diamonds Into and Exports from Kimberley and Production at Griqualand West Mines, Cape Colony for Dec. 31, 1887.Kimberley: Board For The Protection of Mining Interests., 23P.Africa, South Africa, Griqualand WestMining Economics
DS1860-0778
1893
Government PrinterGovernment PrinterReports of the Inspector of Mines Kimberley, Inspector of Claims Barkly west, Inspector of Mines Millwood, Manager for the Vooruitsigt Estate, Kimberley for the Year 1892.Cape Town Parliamentary Report., No. G26-93, 29P.South Africa, Griqualand West, Kimberley AreaProduction
DS1860-0825
1894
Government PrinterGovernment PrinterReports of the Inspectors of Diamond Mines in the Late Province of Griqualand West in the Year 1893.Cape Town Parliamentary Report., No. G38-94, 28P.Africa, South Africa, Cape ProvinceProduction
DS1860-0870
1895
Government PrinterGovernment PrinterReports of the Inspector of Diamond Mines in the Late Province of Griqualand West for the Year 1894.Cape Town Parliamentary Report., No. G25-95, 28P.Africa, South Africa, Cape ProvinceProduction
DS1860-0919
1896
Government PrinterGovernment PrinterReports of the Inspector of Diamond Mines in the Late Province of Griqualand West for the Year 1895.Cape Town Parliamentary Report, No. G49-96, 26P.Africa, South Africa, Cape Province, Kimberley AreaProduction
DS1860-0967
1897
Government PrinterGovernment PrinterReports of the Inspector of Diamond Mines in the Late Province of Griqualand West for the Year 1896.Cape Town Parliamentary Report, No. G38-97, 35P.Africa, South Africa, Cape ProvinceProduction
DS1860-1013
1898
Government PrinterGovernment PrinterReports of the Inspector of Mines Kimberley and Barkly West for the Year 1897.Cape Town Parliamentary Report, No. G43-98, 32P.Africa, South Africa, Cape ProvinceProduction
DS1860-1059
1899
Government PrinterGovernment PrinterReports of the Inspector of Diamond Mines in the Late Province of Griqualand West for the Year 1898.Cape Town Parliamentary Report, No. G32-99, 31P.Africa, South Africa, Cape Province, Kimberley AreaProduction
DS1995-0669
1995
Govers, R.Govers, R., Wortel, M.J.R.Extension of stable continental lithosphere and the initiation of lithospheric scale faultsTectonics, Vol. 14, No. 4, August pp. 1041-1055MantleContinental lithosphere, Model -boudinage, strain weakening, diffusion creep
DS1997-0760
1997
Govers, R.Meijer, P.Th., Govers, R., Wortel, M.J.R.Forces controlling the present day state of stress in the AndesEarth and Planetary Science Letters, Vol. 148, No. 1-2, Apr. 1, pp. 157-AndesTectonics
DS2002-0220
2002
Govers, R.Buiter, S.J.H., Govers, R., Wortel, M.J.R.Two dimensional simulations of surface deformation caused by slab detachmentTectonophysics, Vol. 354, 3-4, pp. 195-210.GlobalTectonics - not specific to diamonds
DS200512-0358
2005
Govers, R.Govers, R., Wortel, M.J.R.Lithosphere tearing at STEP faults: response to edges of subduction zones.Earth and Planetary Science Letters, Vol. 236, pp. 505-523.Pacific IslandsGeodynamics, plate tectonics - not specific to diamonds
DS200812-0269
2008
Govers, R.De Franco, R., Govers, R., Wortel, R.Nature of the plate contact and subduction zones diversity.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 241-244.MantleSubduction
DS200812-0270
2008
Govers, R.De Franco, R., Govers, R., Wortel, R.Dynamics of continental collision: influence of the plate contact.Geophysical Journal International, Vol. 174, 3, pp. 1101-1120.MantleTectonics
DS201112-0047
2011
Govers, R.Baes, M., Govers, R., Wortel, R.Subduction initiation along the inherited weakness zone at the edge of a slab: insights from numerical models.Geophysical Journal International, Jan. 25, in press availableMantleSubduction
DS201112-0048
2011
Govers, R.Baes, M., Govers, R., Wortel, R.Subduction initiation along the inherited weakness zone at the edge of a slab: insights from numerical models.Geophysical Journal International, Vol. 184, 3, pp. 991-1008.MantleSubduction
DS201112-0049
2011
Govers, R.Baes, M., Govers, R., Wortel, R.Switching between alternative responses of the lithosphere to continental collision.Geophysical Journal International, In press availableMantleSubduction
DS1996-0553
1996
Govorov, G.I.Govorov, G.I., Vysotskiy, S.V., Boyko, S.A..First boninite find on Sakhalin IslandDoklady Academy of Sciences, Vol. 336, pp. 154-159Russia, Sakhalin IslandBoninite
DS1984-0309
1984
Govorov, I.N.Govorov, I.N., Blagodareva, N.S., Kirykhina, N.I., Kharkiv, A.D.Primary Potassium Minerals in Deep Seated Eclogites of YakutiaInternational Geology Review, Vol. 26, No. 11, November pp. 1290-1294RussiaEclogites
DS1986-0299
1986
Govorov, I.N.Govorov, I.N., Blagodareva, N.S., Kiryukhina, N.I., Kharkiv, A.D.Primary potassium minerals in plutonic eclogite xenoliths from YakutiaDoklady Academy of Science USSR, Earth Science Section, Vol. 276, January pp. 123-RussiaMineralogy, eclogite
DS1991-0595
1991
Govorov, I.N.Govorov, I.N., Badredinov, Z.G., Dardykins, L.N., et al.Ultramafic volcanic rocks of the shoshonite-latite seriesDoklady Academy of Sciences USSR Earth Science Scetion, Vol. 310, No. 1-6, September pp. 125-128RussiaShoshonite, Ultramafic
DS200612-0413
2006
Gowan, E.Fredericksen, A.W., Ferguson, I.J., Eaton, D., Miong, S-K., Gowan, E.Mantle fabric at multiple scales across an Archean Proterozoic boundary, Grenville Front, Canada.Physics of the Earth and Planetary Interiors, Vol. 158, 2-4, pp. 240-263.Canada, Ontario, QuebecGeophysics - seismics, SKS, tomography
DS200712-0328
2006
Gowan, E.Frederiksen, A.W., Ferguson, I.J., Eaton, D., Miong, S.K., Gowan, E.Mantle fabric at multiple scales across an Archean Proterozoic boundary front, Canada.Physics of the Earth and Planetary Interiors, Vol. 158, 2-4, Oct. 16, pp. 240-263.CanadaTectonics
DS1996-0554
1996
Gowd, T.N.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
DS1992-1105
1992
Gower, C.Murthy, G., Gower, C., et al.Paleomagnetism of Eocambrian Long Range dikes and Double Mer Formation fromLabrador.Canadian Journal of Earth Sciences, Vol. 29, pp. 1224-34.Labrador, Ungava, QuebecPaleomagnetics, Dike swarms
DS1986-0300
1986
Gower, C.F.Gower, C.F., Erdmer, P., Wardle, R.J.The Double Mer formation and the lake Melville rfit system, easternLabrador.Canadian Journal of Earth Sciences, Vol. 23, pp. 359-68.Quebec, LabradorMafic dikes
DS1988-0264
1988
Gower, C.F.Gower, C.F., Erdmer, P.Proterozoic metamorphism in the Grenville Province: a study in the Double Mer Lake Melville area, eastern LabCanadian Journal of Earth Sciences, Vol. 25, pp. 1895-1905.Labradormetamorphism
DS1989-1079
1989
Gower, C.F.Murthy, G., Gower, C.F., et al.Paleomagnetism of pre-Grenvillian mafic intrusions from the GrenvilleProvince, southeast Labrador.Canadian Journal of Earth Sciences, Vol. 26, pp. 2541-55.Labrador, QuebecGeophysics - paleomagnetics
DS1989-1279
1989
Gower, C.F.Rivers, T., Martignole, J., Gower, C.F., Davidson, A.New tectonic divisions of the Grenville Province southeastCanadianshieldTectonics, Vol. 8, No. 1, February pp. 63-84OntarioOrogeny -Grenville, Tectonics
DS1991-0596
1991
Gower, C.F.Gower, C.F., et al.Grevillian magmatism in the eastern Greville Province, CanadaPrecambrian Research, Vol. 51, pp. 315-36.Labrador, Quebec, Mealy MountainsMagmatism
DS1992-0594
1992
Gower, C.F.Gower, C.F.The relevance pf Baltic shield metallogeny to mineral exploration inLabardor.Geol. Suv. Newfoundland, Paper, 92-1, 331-366.Quebec, LabradorMetallogeny - not specific to diamonds, Tectonics, structure
DS1992-0595
1992
Gower, C.F.Gower, C.F.The relevance of Baltic shield metallogeny to mineral exploration inLabradorReprinted from NWFLD Current Research, Report 92-1, 331-366Quebec, LabradorMetallogeny, Baltic shield
DS1992-0596
1992
Gower, C.F.Gower, C.F., Sharer, U., Heaman, L.M.The Labradorian Orogeny in the Grenville Province, eastern Labrador, Canada.Canadian Journal of Earth Sciences, Vol. 29, pp. 1944-57.Quebec, Labrador, UngavaOrogeny, Tectonics
DS1994-0646
1994
Gower, C.F.Gower, C.F., Tucker, R.D.Distribution of pre-1400 Ma crust Grenville province: implications rifting in Laurentia-Baltica during geon14Geology, Vol. 22, No. 9, September pp. 827-830.OntarioGeochronology, Mafic dikes
DS1994-0647
1994
Gower, C.F.Gower, C.F., Tucker, R.D.Distribution of pre-1400 Ma crust in Grenville: implications for rifting Laurentia-Baltica during geon 14Geology, Vol. 22, No. 9, Sept. pp. 827-830OntarioGeochronology, Tectonics
DS1995-0730
1995
Gower, C.F.Hall, J., Wardle, R.J., Gower, C.F., Kerr, A., Coffin, KeenProterozoic orogens of the northeastern Canadian Shield: new information from Lithoprobe ESCOOT seismicsCanadian Journal of Earth Sciences, Vol. 32, No. 8, Aug. pp. 1119-1131.GlobalGeophysics -seismics ESCOOT., Nain, Makkovik provinces
DS1996-0555
1996
Gower, C.F.Gower, C.F.Proterozoic evolution in the North Atlantic realm. Conference report (held August 1996)Geoscience Canada, Vol. 23, No. 3, Sept. pp. 158-160GlobalNorth Atlantic Craton, Continental reconstruction
DS1996-1068
1996
Gower, C.F.Park, J.K., Gower, C.F.Paleomagnetism of pre-Grenvillian mafic rocks from the northeast Grenvilleprovince, Labrador... track...Canadian Journal of Earth Sciences, Vol. 33, pp. 746-56.Quebec, Labrador, UngavaGeophysics - Paleomagnetism, Mafic plutonic rocks
DS1997-0012
1997
Gower, C.F.Ahall, K.I., Gower, C.F.The Gothian and Labradorian orogens: variations in accretionary tectonismalong Paleoproterozoicmargin..Gff., Vol. 119, pp. 181-191.Scandinavia, LabradorOrogeny, Laurentia-Baltica
DS1997-0315
1997
Gower, C.F.Emslie, R.F., Hamilton, M.A., Gower, C.F.The Michael gabbro and other mesoproterozoic lithospheric probes in southern and central labrador.Canadian Journal of Earth Sciences, Vol. 34, pp. 1566-80.Quebec, Labrador, UngavaLithosphere, Tectonics
DS1997-0433
1997
Gower, C.F.Gower, C.F., Hall, J., Kifoil, G.J., Quinlan, WardleRoots of the Labradorian orogen in the Grenville Province in southeastLabrador: evidence from seismic.Tectonics, Vol. 16, No. 5, Oct. pp. 795-809Labrador, Quebec, UngavaGeophysics - seismics offshore, Model - Gravity, geodynamics, tectonics
DS1997-0586
1997
Gower, C.F.Kerr, A., Hall, J., Wardle, R.J., Gower, C.F., Ryan, B.New reflections on the structure and evolution of the Makkovikian Ketilidian Orogen in Labrador and GreenlandTectonics, Vol. 16, No. 6, Dec. pp. 942-965.Labrador, GreenlandTectonics, Geophysics - seismology
DS2002-0605
2002
Gower, C.F.Gower, C.F., Krogh, T.E.A U Pb geochronological review of the Proterozoic history of the eastern Grenville Province.Canadian Journal of Earth Science, Vol.39,5, May, pp.795-829.QuebecTectonics - New Quebec and Torngat Orogens
DS200412-0810
2004
Gower, C.F.Heaman, L.M., Gower, C.F., Perreault, S.The timing of Proterozoic magmatism in the Pinware terrane of southeast Labrador, easternmost Quebec and northwest Newfoundland.Canadian Journal of Earth Sciences, Vol. 41, 2, February pp. 127-150.Canada, Quebec, LabradorMagmatism, geochronology
DS2002-0900
2002
Gower, C.K.Krogh, T.E., Kamo, S., Gower, C.K., Owen, J.V.Augmented and reassessed U Pb geochronological dat a from the Labradorian Grenvillian front in the Smokey Archipelago Eastern Labrador.Canadian Journal of Earth Science, Vol.39,5, May, pp.831-43.LabradorGeochronology
DS201812-2883
2018
Gowera, R.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
DS1990-1004
1990
Goydas, M.J.McConnell, D.A., Goydas, M.J., Smith, G.N., Chitwood, J.P.Morphology of the frontal fault zone, southwest Oklahoma: implications for deformation and deposition in the Wichita uplift and Anadarko basinGeology, Vol. 18, No. 7, July pp. 634-637GlobalTectonics
DS2000-0208
2000
Gozalvez, M.R.Davila, F.M., Lira, R., Gozalvez, M.R.Carbonatites in the western border of Sierras Subandias ( Salta, Argentina)Igc 30th. Brasil, Aug. abstract only 1p.ArgentinaCarbonatite - dikes
DS2000-0356
2000
GPS WorldGPS WorldDiamond in the rough. Using GPS for better locationing..Gps World, Vol. 11, No. 1, pp. 20-24.South AfricaNews item, GPS at Alexkor and Port Nolloth
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