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SDLRC - Scientific Articles all years by Author - G-Gh


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 - G-Gh
Posted/
Published
AuthorTitleSourceRegionKeywords
DS201912-2805
2019
G, M.McCoy-West, A.J., Chowdhury, P., Burton, K.W., Sossi, P., Nowell, G,M., Fitton, J.G., Kerr, A.C., Cawood, P.A., Williams, H.M.Extensive crustal extraction in Earth's early history inferred from molybdenum isotopes.Nature Geoscience, Vol. 12, pp. 946-951.Mantlepicrites

Abstract: Estimates of the volume of the earliest crust based on zircon ages and radiogenic isotopes remain equivocal. Stable isotope systems, such as molybdenum, have the potential to provide further constraints but remain underused due to the lack of complementarity between mantle and crustal reservoirs. Here we present molybdenum isotope data for Archaean komatiites and Phanerozoic komatiites and picrites and demonstrate that their mantle sources all possess subchondritic signatures complementary to the superchondritic continental crust. These results confirm that the present-day degree of mantle depletion was achieved by 3.5 billion years ago and that Earth has been in a steady state with respect to molybdenum recycling. Mass balance modelling shows that this early mantle depletion requires the extraction of a far greater volume of mafic-dominated protocrust than previously thought, more than twice the volume of the continental crust today, implying rapid crustal growth and destruction in the first billion years of Earth’s history.
DS201212-0215
2012
G & G eBriefG & G eBriefGemesis CVD grown synthetic diamonds characterized.Gems & Gemology Lab Notes, 1p.TechnologySynthetic diamonds
DS201212-0216
2012
G & G eBriefG & G eBriefLarge artifically irradiated yellow diamond.Gems & Gemology Lab Notes, 1p.TechnologyDiamonds - irradition
DS201212-0217
2012
G & G eBriefG & G eBriefType Iib CVD synthetic diamond.G & G Brief, August 1/2p.TechnologyDiamond - synthetics
DS201212-0218
2012
G & G eBriefG & G eBriefDiamond type. Brief summary of 1a, 1b, 11a and 11b.G & G Brief, Sept 12, 1/3p.TechnologyDiamond category
DS201212-0219
2012
G & G eBriefG & G eBriefDiamond basics: part 2. Fluorescence and phosphoresence.G & G Brief, 1/4p.TechnologyDiamond - radiation
DS201212-0220
2012
G & G eBriefG & G eBriefMulti-treated yellowish green diamond.G & G Brief, Vol. 3, 8, May 8, 1/4p.TechnologyHPHT treatment
DS201212-0221
2012
G & G ebriefG & G ebriefDiamond with unusual omphacite and pyrope-almandine garnet inclusion.G & G Brief, Vol. 4, 2, Nov. 14, 1/4p.TechnologyDiamond inclusion
DS201212-0222
2012
G & G ebriefG & G ebriefDiamond basics: part 3: how color happens in diamonds.G & G Brief, Vol. 4, 2, Nov. 14, 1/4p.TechnologyDiamond colour
DS201212-0223
2012
G & G eBriefG & G eBriefHPHT grown synthetic diamond - DiamondViewG & G Brief, Vol. 3, 4, Jan. 14, 1/2p.TechnologyDiamond synthesis
DS201212-0224
2012
G & G eBriefG & G eBriefGlobal diamond demand stays strong. G & G Brief, Vol. 3, 4, Jan. 14, 1/2p.GlobalEconomics
DS201312-0286
2012
G & G ebriefG & G ebriefDiamond with diopside-pyrope contact inclusion pair.Gems & Gemology, Vol. 4, 3, 1/4p.TechnologyDiamond inclusion
DS201312-0287
2013
G & G ebriefsG & G ebriefsArtificially irradiated brown diamond.Gems & Gemology, 1/2p.TechnologyDiamond - colour
DS201201-0842
2011
G & G Lab notesG & G Lab notesGem quality CVD synthetic diamonds from Gemesis.Gems & Gemology, Vol. 47, 3, pp. 227-228.TechnologyGemesis CVD
DS201201-0843
2011
G & G Lab notesG & G Lab notesBlack diamond, colored by strong plastic deformation.Gems & Gemology, Vol. 47, 3, pp. 223.TechnologyBlack diamond
DS201201-0844
2011
G & G Lab notesG & G Lab notesColorless untreated diamonds with high levels of strain. Type IIaGems & Gemology, Vol. 47, 3, pp. 224-5.TechnologyDiamond morphology
DS201604-0606
2015
G & G Lab notesG & G Lab notesGraphite inclusions forming octahedral outline in diamond.Gems & Gemology Lab Notes, Vol. 51, 4, winter pp. 428-429.TechnologyDiamond inclusions
DS201604-0607
2015
G & G Lab notesG & G Lab notesVery large type 1b natural diamond ( yellow)Gems & Gemology Lab notes, Vol. 51, 4, winter pp. 430-431.TechnologyType 1b diamond
DS201903-0550
2019
G.Wang, D., Vervoort, J.D., Fisher, C.M., Cao, H. Li, G.Integrated garnet and zircon - titanate geochronology constrains the evolution of ultra high pressure terranes: an example from the Sulu orogen.Journal of Metamorphic Geology, in press availableChinaUHP

Abstract: Dating ultrahigh?pressure (UHP) metamorphic rocks provides important timing constraints on deep subduction zone processes. Eclogites, deeply subducted rocks now exposed at the surface, undergo a wide range of metamorphic conditions (i.e., deep subduction and exhumation) and their mineralogy can preserve a detailed record of chronologic information of these dynamic processes. Here we present an approach that integrates multiple radiogenic isotope systems in the same sample to provide a more complete timeline for the subduction?collision?exhumation processes, based on eclogites from the Dabie?Sulu orogenic belt in eastern China, one of the largest ultrahigh?pressure (UHP) terranes on Earth. In this study, we integrate garnet Lu?Hf and Sm?Nd ages with zircon and titanite U?Pb ages for three eclogite samples from the Sulu UHP terrane. We combine this age information with Zr?in?rutile temperature estimates, and relate these multiple chronometers to different P?T conditions. Two types of rutile, one present as inclusions in garnet and the other in the matrix, record the temperatures of UHP conditions and a hotter stage, subsequent to the peak pressure (“hot exhumation”), respectively. Garnet Lu?Hf ages (c. 238 to 235 Ma) record the initial prograde growth of garnet, while coupled Sm?Nd ages (c. 219 to 213 Ma) reflect cooling following hot exhumation. The maximum duration of UHP conditions is constrained by the age difference of these two systems in garnet (c. 235 to 220 Ma). Complementary zircon and titanite U?Pb ages of c. 235 ? 230 Ma and c. 216 ? 206 Ma provide further constraints on the timing of prograde metamorphism and the "cold exhumation", respectively. We demonstrate that timing of various metamorphic stages can thus be determined by employing complementary chronometers from the same samples. These age results, combined with published data from adjacent areas, show lateral diachroneity in the Dabie?Sulu orogeny. Three sub?blocks are thus defined by progressively younger garnet ages: western Dabie (243 ? 238 Ma), eastern Dabie?northern Sulu (238 ? 235 Ma,) and southern Sulu terranes (225 ? 220 Ma), which possibly correlate to different crustal slices in the recently proposed subduction channel model. These observed lateral chronologic variations in a large UHP terrane can possibly be extended to other suture zones.
DS1982-0214
1982
G.R. Dale and Associates, Anthion Pty. Ltd.G.R. Dale and Associates, Anthion Pty. Ltd.El 2572 and El 2579 Nt Progress Report, Diamond Exploration1981-1982.Northern Territory Geological Survey Open File Report, No. CR 82/345, 6P.Australia, Northern TerritoryProspecting, Geochemistry, Victoria River Basin
DS1986-0259
1986
Gaal, G.Gaal, G.2200 million years of crustal evolution: the Baltic ShieldBulletin. Geological Survey Finland, Vol. 58, pt. 1, pp. 149-68.Finland, Baltic StatesTectonics
DS1987-0232
1987
Gaal, G.Gaal, G.An outline of the Precambrian evolution of the Baltic ShieldPrecambrian Research, Vol. 35, pp. 15-52.Baltic ShieldTectonics - Saamian Orogeny
DS1991-0522
1991
Gaal, G.Gaal, G., Merriam, D.F.Computer applications in resouce estimation prediction and assessment or metals and petroleuM.Pergamon Press, 455p. approx. $ 125.00 United StatesGlobalComputer applications, Book -ad
DS1992-0504
1992
Gaal, G.Gaal, G.Global Proterozoic tectonic cycles and Early Proterozoic metallogeny #1South African Journal of Geology, Vol. 95, No. 3-4, pp. 80-87PangeaPlate tectonics, Metallogeny, Supercontinent
DS1992-0505
1992
Gaal, G.Gaal, G.Global Proterozoic tectonic cycles and Early Proterozoic metallogeny #2South African Journal of Geology, August pp. 79-87South AfricaTectonics, Metallogeny
DS1975-0512
1977
Gaal, R.A.P.Gaal, R.A.P.The Diamond Dictionary 1977Gemological Institute of America, Santa Monica, CA, 342P. 2ND. EDITION.GlobalKimberlite, Kimberley, Janlib, Diamond
DS1995-0537
1995
GababotseField, 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
DS200812-0374
2008
Gababotse, J.Gababotse, J.Jwaneng mine - the richest diamond deposit.GSSA-SEG Meeting Held July, Johannesburg, 27 Power point slidesAfrica, BotswanaDeposit - Jwaneng
DS201710-2211
2017
Gababotse, J.Armstrong, J.P., Gababotse, J.Karowe diamond mine.11th International Kimberlite Field Trip Guide, Sept. 19p. PdfAfrica, Botswanadeposit - Karowe
DS201708-1642
2017
Gabanakgosi, K.Gabanakgosi, K.Slope stability challenges and solutions for mining kimberlite resources hosted in structurally complex country rock: dip slope mining at Jwaneng mine, Botswana.11th. International Kimberlite Conference, OralAfrica, Botswanadeposit - Jwaneng
DS201712-2681
2018
Gabanakgosi, K.Creus, P.K., Basson, I.J., Stoch, B., Mogorosi, O., Gabanakgosi, K., Ramsden, F., Gaegopolwe, P.Structural analysis and implicit 3D modelling of Jwaneng mine: insights into deformation of the Transvaal Supergroup in SE Botswana.Journal of African Earth Sciences, Vol. 137, pp. 9-21.Africa, Botswanadeposit - Jwaneng

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

Abstract: Country rock at Jwaneng Diamond Mine provides a rare insight into the deformational history of the Transvaal Supergroup in southern Botswana. The ca. 235 Ma kimberlite diatremes intruded into late Archaean to Early Proterozoic, mixed, siliciclastic-carbonate sediments, that were subjected to at least three deformational events. The first deformational event (D1), caused by NW-SE directed compression, is responsible for NE-trending, open folds (F1) with associated diverging, fanning, axial planar cleavage. The second deformational event (D2) is probably progressive, involving a clockwise rotation of the principal stress to NE-SW trends. Early D2, which was N-S directed, involved left-lateral, oblique shearing along cleavage planes that developed around F1 folds, along with the development of antithetic structures. Progressive clockwise rotation of far-field forces saw the development of NW-trending folds (F2) and its associated, weak, axial planar cleavage. D3 is an extensional event in which normal faulting, along pre-existing cleavage planes, created a series of rhomboid-shaped, fault-bounded blocks. Normal faults, which bound these blocks, are the dominant structures at Jwaneng Mine. Combined with block rotation and NW-dipping bedding, a horst-like structure on the northwestern limb of a broad, gentle, NE-trending anticline is indicated. The early compressional and subsequent extensional events are consistent throughout the Jwaneng-Ramotswa-Lobatse-Thabazimbi area, suggesting that a large area records the same fault geometry and, consequently, deformational history. It is proposed that Jwaneng Mine is at or near the northernmost limit of the initial, northwards-directed compressional event.
DS1988-0040
1988
Gabert, G.Bardinet, C., Gabert, G., Monget, J-M, Zheng YuApplication of multisatellite dat a to thematic mapping #2Geol. Jahrb, Vol. 67, Sect. B., 74p. coloured mapsTanzaniaRemote Sensing, Tectonics
DS1988-0041
1988
Gabert, G.Bardinet, C., Gabert, G., Monget, J-M., Zheng YuApplication of multisatellite dat a to thematic mapping #1Geol. Jahrb, Heft 67, sect. B., 74p. maps approx. 25.00 Database # 1TanzaniaRemote sensing, Structure
DS2002-0493
2002
Gabirelsen, R.H.Gabirelsen, R.H., Braathen, A., Dehls, J., Roberts, D.Tectonic lineaments of NorwayNorsk Geologisk Tidsskrift, Vol. 82, No. 3, pp. 153-174.NorwayTectonics
DS1995-0954
1995
Gable, C.Kincaid, C., Ito, G., Gable, C.Laboratory investigation of the interaction of off axis mantle plumes and spreading centresNature, Vol. 376, No. 6543, Aug. 31, pp. 758-761MantleMantle plumes
DS1992-0506
1992
Gable, C.W.Gable, C.W., King, S.D., Weinstein, S.A.Models of convection driven tectonic plates: a comparison of methods andresultsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 273MantleModel -convection tectonic plates, Tectonics
DS1992-1132
1992
Gable, C.W.O'Connell, R.J., Gable, C.W.Some relations between plate motions and mantle convectionEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 272MantleMantle convection, Tectonics
DS1999-0422
1999
Gable, C.W.Lowman, J.P., Gable, C.W.Thermal evolution of the mantle following continental aggregation in three dimensional convection models.Geophysical Research Letters, Vol. 26, No. 17, Sept. 1, pp. 2649-52.MantleConvection - model
DS2001-0702
2001
Gable, C.W.Lowman, J.P., King, S.D., Gable, C.W.The influence of tectonic plates on mantle convection patterns, temperature and heat flow.Geophys. Jour. International, Vol. 146, No. 3, pp. 619-36.MantleTectonics, Geothermometry
DS2002-0853
2002
Gable, C.W.King, S.D., Lowman, J.P., Gable, C.W.Episodic tectonic plate reorganizations driven by mantle convectionEarth and Planetary Science Letters, Vol. 203, 1, pp. 83-91.MantleTectonics - subduction
DS2003-0847
2003
Gable, C.W.Lowman, J.P., King, S.D., Gable, C.W.The role of the heating mode of the mantle in intermittent reorganization of the plateGeophysical Journal International, Vol. 152, No. 2, pp. 455-67.MantleGeophysics - seismics, melting
DS200812-0378
2008
Gable, C.W.Gait, A.D., Lowman, J.P., Gable, C.W.Time dependence in 3 D mantle convection models featuring evolving plates: effect of lower mantle viscosity.Journal of Geophysical Research, Vol. 113, B08409.MantleGeophysics - seismcis
DS200812-0379
2008
Gable, C.W.Gait, A.D., Lowman, J.P., Gable, C.W.Time dependence in 3 D mantle convection models featuring evolving plates: effect of lower mantle viscosity.Journal of Geophysical Research, Vol. 113, B8, B80409.MantleGeophysics - seismics
DS200912-0455
2008
Gable, C.W.Lowman, J.P., Gait, A.D., Gable, C.W., Kukreja, H.Plumes anchored by a high velocity lower mantle in a 3D mantle convection model featuring dynamically evolving plates.Geophysical Research Letters, Vol. 35, 19, Oct. 16, GLO35342MantleHotspots
DS2002-0494
2002
Gabler, H-E.Gabler, H-E.Applications of magnetic sector ICP-MS in geochemistryJournal of Geochemical Exploration, Vol.75, 1-3, May pp. 1-15.GlobalGeochemistry - techniques, review
DS2003-0433
2003
Gaboret, C.Gaboret, C., Forte, A.M., Montagner, J.P.The unique dynamics of the Pacific hemisphere mantle and its signature on seismicEarth and Planetary Science Letters, Vol. 208, 3-4, pp. 219-233.MantleGeophysics - seismics
DS200412-0596
2003
Gaboret, C.Gaboret, C., Forte, A.M., Montagner, J.P.The unique dynamics of the Pacific hemisphere mantle and its signature on seismic anisotropy.Earth and Planetary Science Letters, Vol. 208, 3-4, pp. 219-233.MantleGeophysics - seismics
DS201509-0405
2015
Gaboury, D.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.
DS1989-0048
1989
Gabov, N.F.Avchenko, O.V, Gabov, N.F., Kozyreva, A.Z., Konikov, A.Z., TravinEclogites of North Muiskaya Block- the composition and genesis.(Russian)Izv. Akad. Nauk SSSR, Ser. Geol., (Russian), No. 5, pp. 68-82RussiaEclogites
DS1989-0049
1989
Gabov, N.F.Avchenko, O.V., Gabov, N.F., Kozyreva, I.V., Konikov, A.Z. Travin.Composition and origin of eclogites of the North Muya blockInternational Geology Review, Vol. 31, No. 8, August pp. 792-805RussiaEclogites, North Muya
DS1989-0457
1989
Gabrielse, H.Gabrielse, H., Yorath, C.J.DNAG # 4. The Cordilleran orogen in CanadaGeoscience Canada, Vol. 16, No. 2, June pp. 67-83CordilleraTectonics-orogeny, Overview
DS1991-0523
1991
Gabrielse, H.Gabrielse, H., Yorath, C.J.Geology of the Cordilleran orogen in Canada. Part of DNAG series.Extracted pages from listing in the index under kimberlite and diatremeGeological Survey of Canada, Vol. 4, pp. 460, 461, 464, 465, 494, 495British ColumbiaBrief overview, Diatreme, kimberlite
DS1991-0524
1991
Gabrielse, H.Gabrielse, H., Yorath, C.J.Geology of the Cordilleran Orogen in Canada. DNAG volume seriesGeological Survey of Canada Geology of Canada DNAG series, No. 4, 840p. $ 80.00British Columbia, CordilleraRegional geology, Table of contents
DS201706-1084
2017
Gabuda, S.P.Khlebopros, R.G., Zakhvataev, V.E., Gabuda, S.P., Kozlova, S.G., Slepkov, V.A.Possible mantle phase transitions by the formation of Si02 peroxides: implications for mantle convection.Doklady Earth Sciences, Vol. 473, 2, pp. 416-418.Mantleconvection

Abstract: On the basis of quantum-chemical calculations of the linear to isomeric bent transition of the SiO2 molecule, it is suggested that the bent to linear transition of SiO2 forms can occur in melted mantle minerals of the lower mantle. This may be important for the formation of the peculiarities of mantle convection and origination of plumes.
DS201912-2837
2019
Gacesa, M.Zahnle, K.J., Gacesa, M., Catling, D.C.Strange messenger: a new history of hydrogen on Earth, as told by xenon.Geochimica et Cosmochimica Acta, Vol. 244, pp. 56-85.Mantleconvection

Abstract: Atmospheric xenon is strongly mass fractionated, the result of a process that apparently continued through the Archean and perhaps beyond. Previous models that explain Xe fractionation by hydrodynamic hydrogen escape cannot gracefully explain how Xe escaped when Ar and Kr did not, nor allow Xe to escape in the Archean. Here we show that Xe is the only noble gas that can escape as an ion in a photo-ionized hydrogen wind, possible in the absence of a geomagnetic field or along polar magnetic field lines that open into interplanetary space. To quantify the hypothesis we construct new 1-D models of hydrodynamic diffusion-limited hydrogen escape from highly-irradiated CO2-H2-H atmospheres. The models reveal three minimum requirements for Xe escape: solar EUV irradiation needs to exceed that of the modern Sun; the total hydrogen mixing ratio in the atmosphere needs to exceed 1% (equiv. to CH4); and transport amongst the ions in the lower ionosphere needs to lift the Xe ions to the base of the outflowing hydrogen corona. The long duration of Xe escape implies that, if a constant process, Earth lost the hydrogen from at least one ocean of water, roughly evenly split between the Hadean and the Archean. However, to account for both Xe’s fractionation and also its depletion with respect to Kr and primordial 244Pu, Xe escape must have been limited to small apertures or short episodes, which suggests that Xe escape was restricted to polar windows by a geomagnetic field, or dominated by outbursts of high solar activity, or limited to transient episodes of abundant hydrogen, or a combination of these. Xenon escape stopped when the hydrogen (or methane) mixing ratio became too small, or EUV radiation from the aging Sun became too weak, or charge exchange between Xe+ and O2 rendered Xe neutral. In our model, Xe fractionation attests to an extended history of hydrogen escape and Earth oxidation preceding and ending with the Great Oxidation Event (GOE).
DS1999-0513
1999
Gacia, M.O.Norman, M.D., Gacia, M.O.Primitive magmas and source characteristics of Hawaiian plume: petrology and geochemistry of shield picrites.Earth and Planetary Science Letters, Vol. 169, No. 1-2, Apr. 30, pp. 27-44.HawaiiPicrites, Geochemistry
DS1992-0507
1992
Gaciri, S.J.Gaciri, S.J.Lineament map of Kenya: correlations of lineaments to known geologicaldataTectonophysics, Vol. 209, pp. 139-142. extended abstractEast Africa, KenyaTectonics, Structure, lineaments
DS1995-1332
1995
Gaciri, S.J.Negecu, W.M., Gaciri, S.J.Lithostratigraphy, provenance and facies distribution on Archean cratonic successions in western KenyaJournal of African Earth Sciences, Vol. 21, No. 3, Oct. 1, pp. 359-372KenyaCraton, Stratigraphy
DS201112-0530
2011
Gadas, P.Kmicek, L., Cempirek, J., Havlin, A., Pfichystal, A., Houzar, S., Kmichkova, M., Gadas, P.Mineralogy and petrogenesis of Ba Ti Zr rich peralkaline dyke from Sebkovice : recognition of the most lamproitic Varascan intrusion.Lithos, Vol. 121, 1-4, pp. 74-86.Europe, Czech RepublicLamproite
DS202009-1637
2020
Gadas, P.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.
DS201806-1239
2018
Gadre, S.R.Patwardhan, B., Nagarkar, S., Gadre, S.R., Lakhotia, S.C., Katoch, V.M., Moher, D.A critical analysis of the 'UGC' approved list of journals.Current Science, Vol. 114, 6, Mar. 25, pp. 1299-1303.Indialegal

Abstract: Scholarly journals play an important role in maintaining the quality and integrity of research by what they publish. Unethical practices in publishing are leading to an increased number of predatory, dubious and low-quality journals worldwide. It has been reported that the percentage of research articles published in predatory journals is high in India. The University Grants Commission (UGC), New Delhi has published an 'approved list of journals', which has been criticized due to inclusion of many substandard journals. We have developed a protocol with objective criteria for identifying journals that do not follow good publication practices. We studied 1336 journals randomly selected from 5699 in the university source component of the 'UGC-approved list'. We analysed 1009 journals after excluding 327 indexed in Scopus/Web of Science. About 34.5% of the 1009 journals were disqualified under the basic criteria because of incorrect or non-availability of essential information such as address, website details and names of editors; another 52.3% of them provided false information such as incorrect ISSN, false claims about impact factor, claimed indexing in dubious indexing databases or had poor credentials of editors. Our results suggest that over 88% of the non-indexed journals in the university source component of the UGC-approved list, included on the basis of suggestions from different universities, could be of low quality. In view of these results, the current UGC-approved list of journals needs serious reconsideration. New regulations to curtail unethical practices in scientific publishing along with organization of awareness programmes about publication ethics at Indian universities and research institutes are urgently needed.
DS200912-0622
2008
Gaede, H.Regenauer-Lieb, K., Sommer, H., Gaede, H., Gaede, O.Weertman cracks and the fast extraction of diamonds from the Earth's mantle.American Geological Union, Fall meeting Dec. 15-19, Eos Trans. Vol. 89, no. 53, meeting supplement, 1p. abstractAfrica, BotswanaDeposit - Jwaneng
DS200912-0622
2008
Gaede, O.Regenauer-Lieb, K., Sommer, H., Gaede, H., Gaede, O.Weertman cracks and the fast extraction of diamonds from the Earth's mantle.American Geological Union, Fall meeting Dec. 15-19, Eos Trans. Vol. 89, no. 53, meeting supplement, 1p. abstractAfrica, BotswanaDeposit - Jwaneng
DS200912-0715
2009
Gaede, O.Sommer, H., Regenauer-Lieb, K., Gaede, O.Weertman cracks and the near sonic extraction of diamonds from the Earth's mantle.Goldschmidt Conference 2009, p. A1249 Abstract.Africa, BotswanaDeposit - Jwaneng
DS201112-0986
2011
Gaede, O.Sommer, H., Regenauer-Lieb, K., Gaede, O., Jung, H., Gasharova, B.WEERTMAN cracks: a possible mechanism for near sonic speed diamond extraction from the Earth's mantle.Goldschmidt Conference 2011, abstract p.1908.MantleTransport for diamond bearing kimberlite melts
DS201712-2681
2018
Gaegopolwe, P.Creus, P.K., Basson, I.J., Stoch, B., Mogorosi, O., Gabanakgosi, K., Ramsden, F., Gaegopolwe, P.Structural analysis and implicit 3D modelling of Jwaneng mine: insights into deformation of the Transvaal Supergroup in SE Botswana.Journal of African Earth Sciences, Vol. 137, pp. 9-21.Africa, Botswanadeposit - Jwaneng

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

Abstract: Country rock at Jwaneng Diamond Mine provides a rare insight into the deformational history of the Transvaal Supergroup in southern Botswana. The ca. 235 Ma kimberlite diatremes intruded into late Archaean to Early Proterozoic, mixed, siliciclastic-carbonate sediments, that were subjected to at least three deformational events. The first deformational event (D1), caused by NW-SE directed compression, is responsible for NE-trending, open folds (F1) with associated diverging, fanning, axial planar cleavage. The second deformational event (D2) is probably progressive, involving a clockwise rotation of the principal stress to NE-SW trends. Early D2, which was N-S directed, involved left-lateral, oblique shearing along cleavage planes that developed around F1 folds, along with the development of antithetic structures. Progressive clockwise rotation of far-field forces saw the development of NW-trending folds (F2) and its associated, weak, axial planar cleavage. D3 is an extensional event in which normal faulting, along pre-existing cleavage planes, created a series of rhomboid-shaped, fault-bounded blocks. Normal faults, which bound these blocks, are the dominant structures at Jwaneng Mine. Combined with block rotation and NW-dipping bedding, a horst-like structure on the northwestern limb of a broad, gentle, NE-trending anticline is indicated. The early compressional and subsequent extensional events are consistent throughout the Jwaneng-Ramotswa-Lobatse-Thabazimbi area, suggesting that a large area records the same fault geometry and, consequently, deformational history. It is proposed that Jwaneng Mine is at or near the northernmost limit of the initial, northwards-directed compressional event.
DS200812-0280
2008
Gaertner, M.Delechat, C., Gaertner, M.Exchange rate assessment in a resource - dependent economy: the case of Botswana.IMF Working Papers, April 1, no. 8083, 200, pp. 1-29. Avail from ingentaAfrica, BotswanaEconomics
DS1993-0475
1993
Gaeta, M.Gaeta, M., Trigil, R.Ultramafic xenoliths bearing on the origin of central Italy potassicmagmatismTerra Abstracts, IAGOD International Symposium on mineralization related to mafic, Vol. 5, No. 3, abstract supplement p. 15ItalyXenoliths, Potassic magma
DS201312-0583
2013
Gaeta, M.Masotta, M., Mollo, S., Freda, C., Gaeta, M., Moore, G.Clinopyroxene liquid thermometers and barometers specific to alkaline differentiated magmas.Contributions to Mineralogy and Petrology, Vol. 166, 6, pp. 1545-1561.Europe, ItalyCurrent volcanic eruptions
DS200612-0542
2006
Gaetani, G.Hart, S., Gaetani, G.Mantle lead paradoxes: the sulphide solution.Contributions to Mineralogy and Petrology, Vol. 152, 3, pp. 295-308.MantleGeochemistry
DS201412-0258
2014
Gaetani, G.Gaetani, G., O'Leary, J., Koga, K., Hauri, E., Rose-Koga, E., Monteleone, B.Hydration of mantle olivine under variable water and oxygen fugacity conditions.Contributions to Mineralogy and Petrology, Vol. 167, 2, pp. 1-14.MantleOlivine
DS201607-1346
2016
Gaetani, G.Gaetani, G.The influence of spinel lherzolite partial melting on oxygen fugacity in the oceanic upper mantle.IGC 35th., Session The Deep Earth 1 p. abstractMantleMelting
DS1993-0476
1993
Gaetani, G.A.Gaetani, G.A., Grove, T.L., Bryan, W.B.The influence of water on the petrogenesis of subduction related igneousrocksNature, Vol. 365, No. 6444, September 23, pp. 332-335GlobalSubduction, Igneous rocks, Mantle
DS1994-0561
1994
Gaetani, G.A.Gaetani, G.A., Grove, T.L.Melting in the sub arc mantle: effects of H2O on primary magmas and the spinel to garnet transition.Mineralogical Magazine, Vol. 58A, pp. 301-302. AbstractMantleMagma transitions, Peridotite
DS1998-0459
1998
Gaetani, G.A.Gaetani, G.A., Grove, T.L.The influence of water on melting of mantle peridotiteContributions to Mineralogy and Petrology, Vol. 131, No. 4, May pp. 323-46.MantleMelting, Peridotite
DS1999-0232
1999
Gaetani, G.A.Gaetani, G.A., Grove, T.L.Wetting of mantle olivine by sulfide melt: implications for Re/Os ratios In mantle peridotite and late stage ..Earth and Planetary Science Letters, Vol. 169, No. 1-2, May 30, pp. 147-64.MantleSulphides, peridotite, Georchronology - late stage core formation
DS2000-0308
2000
Gaetani, G.A.Gaetani, G.A., Watson, E.B.Open system behaviour of olivine hosted melt inclusionsEarth and Planetary Science Letters, Vol.183, No.1-2, Nov.30, pp.27-41.MantleMelting - olivine, Mineral chemistry
DS2002-0495
2002
Gaetani, G.A.Gaetani, G.A., Watson, R.B.Modeling and the major element evolution of olivine hosted melt inclusionsChemical Geology, Vol.183, 1-4, pp.25-41.MantleMelt - inclusions, Geochemistry
DS2003-0434
2003
Gaetani, G.A.Gaetani, G.A., Kent, A.J., Grove, T.L., Hutcheon, I.D., Stolper, E.M.Mineral melt partitioning of trace elements during hydrous peridotite partial meltingContributions to Mineralogy and Petrology, Vol. 145, 4, pp. 391-405.MantlePeridotites
DS200412-0597
2004
Gaetani, G.A.Gaetani, G.A.The influence of melt structure on trace element partitioning near the peridotite solidus.Contributions to Mineralogy and Petrology, Vol. 147, 5, pp. 511-527.TechnologyPeridotite, mineralogy
DS200412-0598
2003
Gaetani, G.A.Gaetani, G.A., Kent, A.J., Grove, T.L., Hutcheon, I.D., Stolper, E.M.Mineral melt partitioning of trace elements during hydrous peridotite partial melting.Contributions to Mineralogy and Petrology, Vol. 145, 4, pp. 391-405.MantlePeridotite
DS200412-0731
2003
Gaetani, G.A.Grove, T.L., Elkins-Tanton, L.T., Parman, S.W., Chatterjee, N., Muntener, O., Gaetani, G.A.Fractional crystallization and mantle melting controls on calc-alkaline differentiation trends.Contributions to Mineralogy and Petrology, Vol. 145, 5, pp. 515-533.MantleGeochemistry - alkaline
DS200612-0495
2006
Gaetani, G.A.Green, T.H., Hauri, E.H., Gaetani, G.A., Adam, J.New calculations on water storage in the upper mantle, and implications for mantle melting models.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 215, abstract only.MantleWater
DS200612-0543
2006
Gaetani, G.A.Hart, S.R., Gaetani, G.A.Mantle Pb paradoxes: the sulfide solution.Contributions to Mineralogy and Petrology, in press availableMantlePetrology - peridotites and lead
DS200612-0548
2006
Gaetani, G.A.Hauri, E.H., Gaetani, G.A., Green, T.H.Partitioning of water during melting of the Earth's upper mantle at H2O undersaturated conditions.Earth and Planetary Science Letters, Vol. 248, 3-4, Aug. 30, pp. 715-734.MantleMelting
DS200812-0375
2008
Gaetani, G.A.Gaetani, G.A., Asimov, P.D., Stolper, E.M.A model for rutile saturation in silicate melts with applications to eclogite partial melting in subduction zones and mantle plumes.Earth and Planetary Science Letters, Vol. 272, 3-4, pp. 720-729.MantleSubduction
DS201312-0106
2013
Gaetani, G.A.Bucholz, C.E., Gaetani, G.A., Behn, M.D., Shimizu, N.Post entrapment modification of volatiles and oxygen fugacity in olivine hosted melt inclusions.Earth and Planetary Science Letters, Vol. 392, pp. 39-49.MantleMelting
DS201606-1088
2016
Gaetani, G.A.Gaetani, G.A.The behavior of Fe3/Efe during partial melting of spinel lherzolite.Geochimica et Cosmochimica Acta, in press availableGeothermometry

Abstract: The use of wet chemistry and X-ray absorption near edge structure (XANES) spectroscopy to determine the oxidation state of Fe in submarine glasses and olivine-hosted melt inclusions has provided important new insights into the global systematics of Fe3+/?Fe in mid-ocean ridge basalts (MORB) [1, 2]. Because MORB are aggregates of near-fractional partial melts formed by decompression melting of variably depleted peridotite, it is difficult to judge the extent to which they directly reflect the oxidation state of the oceanic upper mantle. To provide a theoretical framework within which to interpret Fe3+/?Fe in MORB, I have developed a model that describes the behavior of Fe3+/?Fe during spinel lherzolite partial melting in a system closed to oxygen. Modeling is carried out by calculating the Fe3+/?Fe of olivine using the point defect model of [3], and determining Fe3+/?Fe of the bulk peridotite from mineral-mineral partitioning. The inter-mineral Fe3+/Fe2+ exchange coefficients are derived from Mössbauer data on natural spinel peridotites, and are parameterized in terms of oxygen fugacity, temperature, and the Fe content of the olivine. The Fe3+/?Fe of the melt is determined by combining mass-balance with an equation relating the Fe3+/?Fe of the melt to the fugacity of oxygen [4]. Spinel lherzolite partial melting is modeled after [5]. Modeling results indicate that oxygen fugacity does not follow the fayalite-magnetite-quartz (FMQ) buffer during partial melting. For isobaric partial melting, the system becomes reduced relative to FMQ with increasing extent of melting. This results from an increase in the FMQ buffer with increasing temperature, whereas oxygen fugacity in the peridotite remains nearly constant. Conversely, during polybaric partial melting the oxidation state of the residual peridotite increases relative to FMQ. The effective partition coefficient for Fe3+is larger than previously thought, so that a redox couple with S is not required to explain its compatibility during partial melting.
DS201607-1385
2016
Gaetani, G.A.Woodland, A., Gaetani, G.A.Redox reactions as controls on geochemical processes in the crust and mantle.IGC 35th., Session The Deep Earth 1 p. abstractMantleGeochemistry
DS201704-0645
2017
Gaetani, G.A.Sarafian, E., Gaetani, G.A., Hauri, E.H., Sarafian, A.R.Experimental constraints on the damp peridotite solidus and oceanic mantle potential temperature.Science, Vol. 355, 6328, pp. 942-945.MantleGeothermometry

Abstract: Decompression of hot mantle rock upwelling beneath oceanic spreading centers causes it to exceed the melting point (solidus), producing magmas that ascend to form basaltic crust ~6 to 7 kilometers thick. The oceanic upper mantle contains ~50 to 200 micrograms per gram of water (H2O) dissolved in nominally anhydrous minerals, which -relative to its low concentration-has a disproportionate effect on the solidus that has not been quantified experimentally. Here, we present results from an experimental determination of the peridotite solidus containing known amounts of dissolved hydrogen. Our data reveal that the H2O-undersaturated peridotite solidus is hotter than previously thought. Reconciling geophysical observations of the melting regime beneath the East Pacific Rise with our experimental results requires that existing estimates for the oceanic upper mantle potential temperature be adjusted upward by about 60°C.
DS201805-0942
2018
Gaetani, G.A.Cruz-Uribe, A.M., Marschall, H.R., Gaetani, G.A., Le Roux, V.Generation of alkaline magmas in subduction zones by partial melting of melange diapirs - an experimental study.Geology, Vol. 48, 4, pp. 343-346.Technologysubduction

Abstract: Alkaline lavas occur globally in subduction-related volcanic arcs. Conventional models for the origin of these lavas typically invoke a multi-stage process in which mantle wedge peridotite, enriched in phlogopite and/or amphibole due to prior metasomatism, partially melts during infiltration by fluids and melts derived from subducted oceanic lithosphere. However, geochemical systematics in the majority of subduction-related alkaline lavas require physical mixing of subducted components and peridotite prior to partial melting. This can be explained by the mélange diapir model, which predicts the generation of arc magmas during advection of buoyant material from the slab-wedge interface into the mantle wedge below arcs. Here we report results from experiments in which natural mélange materials were partially melted at upper mantle conditions to produce alkaline magmas. Partial melts produced in our experiments have trace-element abundance patterns that are typical of alkaline arc lavas, such as enrichment in large ion lithophile elements (LILEs) and depletion in Nb and Ta. These results favor generation of alkaline magmas in the arc and backarc regions of subduction zones by partial melting of mélange materials rather than previously metasomatized peridotite.
DS202105-0798
2021
Gaetani, G.A.Wallace, P.J., Plank, T., Bodnar, R.J., Gaetani, G.A., Shea, T.Olivine-hosted melt inclusions: a microscopic perspective on a complex magmatic world.Annual Review of Earth Planetary Sciences, Vol. 49, pp. 465-484.MantleMagmatism

Abstract: Inclusions of basaltic melt trapped inside of olivine phenocrysts during igneous crystallization provide a rich, crystal-scale record of magmatic processes ranging from mantle melting to ascent, eruption, and quenching of magma during volcanic eruptions. Melt inclusions are particularly valuable for retaining information on volatiles such as H2O and CO2 that are normally lost by vesiculation and degassing as magma ascends and erupts. However, the record preserved in melt inclusions can be variably obscured by postentrapment processes, and thus melt inclusion research requires careful evaluation of the effects of such processes. Here we review processes by which melt inclusions are trapped and modified after trapping, describe new opportunities for studying the rates of magmatic and volcanic processes over a range of timescales using the kinetics of post-trapping processes, and describe recent developments in the use of volatile contents of melt inclusions to improve our understanding of how volcanoes work.
DS202107-1144
2021
Gaetani, G.A.Wallace, P.J., Plank, T., Bodnar, R.J., Gaetani, G.A., Shea, T.Olivine-hosted melt inclusions: a microscopic perspective on a complex magmatic world.Annual Review of Earth and Planetary Sciences, Vol. 49, pp. 465-494.Mantlemagmatism

Abstract: Inclusions of basaltic melt trapped inside of olivine phenocrysts during igneous crystallization provide a rich, crystal-scale record of magmatic processes ranging from mantle melting to ascent, eruption, and quenching of magma during volcanic eruptions. Melt inclusions are particularly valuable for retaining information on volatiles such as H2O and CO2 that are normally lost by vesiculation and degassing as magma ascends and erupts. However, the record preserved in melt inclusions can be variably obscured by postentrapment processes, and thus melt inclusion research requires careful evaluation of the effects of such processes. Here we review processes by which melt inclusions are trapped and modified after trapping, describe new opportunities for studying the rates of magmatic and volcanic processes over a range of timescales using the kinetics of post-trapping processes, and describe recent developments in the use of volatile contents of melt inclusions to improve our understanding of how volcanoes work. Inclusions of silicate melt (magma) trapped inside of crystals formed by magma crystallization provide a rich, detailed record of what happens beneath volcanoes. These inclusions record information ranging from how magma forms deep inside Earth to its final hours as it ascends to the surface and erupts. The melt inclusion record, however, is complex and hazy because of many processes that modify the inclusions after they become trapped in crystals. Melt inclusions provide a primary archive of dissolved gases in magma, which are the key ingredients that make volcanoes erupt explosively.
DS200512-0308
2005
Gaetskii, R.C.Gaetskii, R.C., Dobrolyubov, A.I.The tidal discrete wave mechanism of tectonic movements in the lithosphere.Doklady Earth Sciences, Vol. 400, 1, pp. 35-39.MantleTectonics
DS1991-0274
1991
Gaffey, M.J.Cloutis, E.A., Gaffey, M.J.Pyroxene spectroscopy revisited: spectral-compositional correlations and relationship to geothermometryJournal of Geophysical Research, Vol. 96, No. E5, December 25, pp. 22, 809-22, 826GlobalGeothermometry, Spectroscopy-pyroxene
DS201412-0131
2014
Gaffey, M.J.Cloutis, E.A., Binzel, R.P., Gaffey, M.J.Asteroids: formation and physical properties of asteroids.Elements, Vol. 10, 1, pp. 19-24.TechnologyAsteroids
DS1993-0477
1993
Gaffey. M.J.Gaffey. M.J.Forging an asteroid-meteorite linkScience, Vol. 260, April 9, p. 167-168GlobalMeteorites
DS200612-0420
2006
Gaffney, A.Gaffney, A., Upton, B.Ocean Island basalt like source of kimberlite magmas from West Greenland revealed by high 3 He 4He ratios.Geology, Vol.34, 4, April pp. 273-276.Europe, GreenlandGeochronology, Group I
DS200612-1403
2006
Gaffney, A.Tachibana, Y., Kaneoka, I., Gaffney, A., Upton, B.Ocean Island basalt like source of kimberlite magmas from West Greenland revealed by high 3He 4He ratios.Geology, Vol. 34, 4, pp. 273-276.Europe, GreenlandMagmatism - kimberlite mineral chemistry
DS2002-0496
2002
Gaffney, A.M.Gaffney, A.M.Environemts of crystallization and compositional diversity of Mauna Loa xenolithsJournal of Petrology, Vol.43,6,pp.963-80.GlobalXenoliths - not specific to diamonds
DS200712-0339
2007
Gaffney, A.M.Gaffney, A.M., Blichert-Toft, J., Nelson, B.K., Bizzarro, M., Rosing, M., Albarec, F.Constraints on source forming processes of West Greenland kimberlites inferred from Hf Nd isotope systematics.Geochimica et Cosmochimica Acta, Vol. 71, 11, June 1, pp. 2820-2836.Europe, GreenlandGeochronology
DS200712-0340
2007
Gaffney, A.M.Gaffney, A.M., Blichert-Toft, J., Nelson, B.K., Bizzarro, M., Rosing, M., Albarede, F.Constraints on source forming processes of West Greenland kimberlites inferred from Hf Nd isotope systematics.Geochimica et Cosmochimica Acta, Vol. 71, 11, pp. 2820-2836.Europe, GreenlandDiamond genesis
DS1980-0133
1980
Gafitullina, D.S.Gafitullina, D.S., Khaydarov, A.A.The Nature of Microzoning in Natural DiamondsTsnigri, No. 153, PP. 64-68.RussiaBlank
DS1985-0208
1985
Gafitullina, D.S.Gafitullina, D.S., Solodova, I.P., Khaidarov, A.A.Trace Elements in Diamonds.(russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 284, No. 6, pp. 1464-1466RussiaDiamond Morphology
DS1987-0233
1987
Gafitullina, D.S.Gafitullina, D.S., Solodova, Yu.P., Khaydarov, A.A.Impurities in diamonds with fibrous textureDoklady Academy of Science USSR, Earth Science Section, Vol. 284, No. 5, Publishing July 1987, pp. 163-166RussiaMineralogy
DS1983-0107
1983
Gafiyllina, D.S.Argunov, K.P., Gafiyllina, D.S., Kirikitsa, S.I., Polykanov, Y.V.A.Trace Elements in Small Natural Diamonds.(russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 270, No. 3, pp. 693-695RussiaDiamond Morphology
DS1995-0574
1995
Gaft, M.Gaft, M., Kagan, B., Shoval, S.Laseroluminescent sorting and identification of diamondsProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 172-74.Russia, SiberiaDiamond morphology, Diamond luminescence
DS200412-0599
2004
Gaft, M.Gaft, M., Resifeld, R., Panczer, G.Luminescence spectroscopy of minerals and materials.Springer, 300p. ISBN 3-540-21918-8 $ 130.00TechnologyBook - luminescence
DS201312-0400
2012
Gagan, M.K.Honda, M., Phillips, D., Kendrick, M.A., Gagan, M.K., Taylor, W.R.Noble gas and carbon isotope ratios in Argyle diamonds, western Australia: evidence for a deeply subducted volatile component.Australian Journal of Earth Sciences, Vol. 59, 8, pp. 1135-1142.AustraliaDeposit - Argyle
DS1900-0752
1909
Gagel, C.Gagel, C.Die Nutzbaren Lagerstaetten von Deutsch SuedwestafrikaZeitschr. Berg. Hutt. U Salinenw., Vol. 57, PP. 173-184.Africa, NamibiaDiamond, Mineral Resources
DS1910-0049
1910
Gagel, C.Gagel, C.Ueber die Fortschritte in der Geologischen Erforschung und Der Bergbaulichen Erschliessung der Deutschen Schutzgebiete Seit 1905.Verh. Deutsch. Kolonkongr., PP. 15-32. ALSO: southwest AFRICA WINDHOEK, PP. 19-24.Southwest Africa, NamibiaGeology
DS1920-0033
1920
Gagel, C.Gagel, C.Die Neueren Fortschritte in der Geologischen Erforschung Und der Bergbaulichen Erschliessung der Deutschen Kolonien.Geologische Rundschau, Vol. 1, PP. 280-284.Southwest Africa, NamibiaGeology, Mining
DS201710-2278
2017
Gagen, M.H.Wolfe, A.P., Reyes, A.V., Royer, D.L., Greenwood, D.R., Doria, G., Gagen, M.H., Siver, P.A., Westgate, J.A.Middle Eocene CO2 and climate reconstructed from the sediment fill of a subarctic kimberlite Maar.Geology , Vol. 45, 7, pp. 619-622.Canada, Northwest Territoriesdeposit - Giraffe

Abstract: Eocene paleoclimate reconstructions are rarely accompanied by parallel estimates of CO2 from the same locality, complicating assessment of the equilibrium climate response to elevated CO2. We reconstruct temperature, precipitation, and CO2 from latest middle Eocene (ca. 38 Ma) terrestrial sediments in the posteruptive sediment fill of the Giraffe kimberlite in subarctic Canada. Mutual climatic range and oxygen isotope analyses of botanical fossils reveal a humid-temperate forest ecosystem with mean annual temperatures (MATs) more than 17 °C warmer than present and mean annual precipitation ?4× present. Metasequoia stomatal indices and gas-exchange modeling produce median CO2 concentrations of ?630 and ?430 ppm, respectively, with a combined median estimate of ?490 ppm. Reconstructed MATs are more than 6 °C warmer than those produced by Eocene climate models forced at 560 ppm CO2. Estimates of regional climate sensitivity, expressed as ?MAT per CO2 doubling above preindustrial levels, converge on a value of ?13 °C, underscoring the capacity for exceptional polar amplification of warming and hydrological intensification under modest CO2 concentrations once both fast and slow feedbacks become expressed.
DS202106-0921
2021
Gagiulo, M.F.Antonini, A., Ganuza, M.L. , Ferracutti, G., Gagiulo, M.F., Matkovic, K., Groller, E., Bjerg, E.A., Castro, S.M.Spinel web: an interactive web application for visualizing the chemical composition of spinel group minerals. ** not specific to diamondsEarth Science Informatics, Vol. 14, pp. 521-528. pdfMantletectonics

Abstract: The spinel group minerals provide useful information regarding the geological environment in which the host rocks were formed, constituting excellent petrogenetic indicators, and guides in the search for mineral deposits of economic interest. In this article, we present the Spinel Web, a web application to visualize the chemical composition of spinel group minerals. Spinel Web integrates most of the diagrams commonly used for analyzing the chemical characteristics of the spinel group minerals. It incorporates parallel coordinates and a 3D representation of the spinel prisms. It also provides coordinated views and appropriate interactions for users to interact with their datasets. Spinel Web also supports semi-automatic categorization of the geological environment of formation through a standard Web browser.
DS1975-1265
1979
GagnonWoussen, G., Gagnon, BONNEAU, Bergeron, DIMROTH, Roy.Lithologie et tectonique des roches Precambriennes et des carbonatites du Saguenay Lac St. Jean.Geological Association of Canada (GAC) Guidebook, Excursion A 3.Quebec, Ungava, LabradorTectonics, Lithology
DS201412-0220
2014
Gagnon, A.Eiler, J.M., Berquist, B., Bourg, I., Cartigny, P., Farquhar, J., Gagnon, A., Guo, W., Halevy, I., Hofman, A., larson, T.E., Levin, N., Schauble, E.A., Stolper, D.Frontiers of stable isotope geoscience.Chemical Geology, Vol. 372, pp. 119-143.TechnologyReview of isotopes
DS1993-0478
1993
Gagnon, G-Y.Gagnon, G-Y., Rainville, J.A kimberlite discovery in the Temiscaminque areaQuebec Exploration Conference summaries held September 15-1th. Val d'Or, pp. 10-12QuebecTemiskaming area
DS200512-0969
2005
Gagnon, J.Shaw, C.S.,Eyzaguirre, J., Fryer, B., Gagnon, J.Regional variations in the mineralogy of metasomatic assemblages in mantle xenoliths with the West Eifel volcanic field, Germany.Journal of Petrology, Vol. 46, 5, May pp. 945-972.Europe, GermanyXenoliths
DS202104-0567
2021
Gagnon, J.E.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
Gagnon, J.E.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.
DS2000-0201
2000
Gahagan, L.M.Dalziel, I.W.D., Mosher, S., Gahagan, L.M.Laurentia Kalahari collision and the assembly of RodiniaJournal of Geology, Vol. 108, pp. 499-513.GlobalCraton, Llano Orogenic belt, Namaqua, Tectonics, suture
DS2002-1575
2002
Gahegan, M.Takatsuka, M., Gahegan, M.GeoVISTA Studio: a codeless visual programming environnment for geoscientific dat a analysis and visualization.Computers and Geosciences, Vol. 28, 10, pp.1131-44.GlobalComputers - programs
DS200612-0173
2006
Gahegan, M.Brodaric, B., Gahegan, M.Representing geoscientific knowledge in cyberinfrastructure: some challenges, approaches and implentatations.In: Sinha, A.K. Geoinformatics: data to knowledge, GSA Special Paper, 397, 397, pp.1-20.TechnologyData - not specific to diamonds
DS200512-0652
2004
Gaherty, D.Lizarralde, D., Gaherty, D., Collins, J.B., Hirth, J.A., Kim, S.D.Spreading rate dependence of melt extraction at mid-ocean ridges from mantle seismic refraction data.Nature, No. 7018, Dec. 9, pp. 744-746.MantleMelting
DS201809-2100
2018
Gaherty, J.Tepp, G., Ebinger, C.J., Zal, H., Gallacher, R., Accardo, N., Shillington, D.J., Gaherty, J., Keir, D., Nyblade, A.A., Mbogoni, G.J., Chindandali, P.R.N., Ferdinand-Wambura, R., Mulibo, G.D., Kamihanda, G.Seismic anistrotropy of the Upper mantle below the western rfit, East Africa.Journal of Geophysical Research, Vol. 123, 7, pp. 5644-5660.Africa, east Africageophysics - seismic

Abstract: Although the East African rift system formed in cratonic lithosphere above a large?scale mantle upwelling, some sectors have voluminous magmatism, while others have isolated, small?volume eruptive centers. We conduct teleseismic shear wave splitting analyses on data from 5 lake?bottom seismometers and 67 land stations in the Tanganyika?Rukwa?Malawi rift zone, including the Rungwe Volcanic Province (RVP), and from 5 seismometers in the Kivu rift and Virunga Volcanic Province, to evaluate rift?perpendicular strain, rift?parallel melt intrusion, and regional flow models for seismic anisotropy patterns beneath the largely amagmatic Western rift. Observations from 684 SKS and 305 SKKS phases reveal consistent patterns. Within the Malawi rift south of the RVP, fast splitting directions are oriented northeast with average delays of ~1 s. Directions rotate to N?S and NNW north of the volcanic province within the reactivated Mesozoic Rukwa and southern Tanganyika rifts. Delay times are largest (~1.25 s) within the Virunga Volcanic Province. Our work combined with earlier studies shows that SKS?splitting is rift parallel within Western rift magmatic provinces, with a larger percentage of null measurements than in amagmatic areas. The spatial variations in direction and amount of splitting from our results and those of earlier Western rift studies suggest that mantle flow is deflected by the deeply rooted cratons. The resulting flow complexity, and likely stagnation beneath the Rungwe province, may explain the ca. 17 Myr of localized magmatism in the weakly stretched RVP, and it argues against interpretations of a uniform anisotropic layer caused by large?scale asthenospheric flow or passive rifting.
DS1999-0233
1999
Gaherty, J.B.Gaherty, J.B., Kato, M., Jordan, T.H.Seismological structure of the upper mantle: a regional comparison of seismic layering.Physical Earth and Planetary Interiors, Vol. 110, pp. 21-41.MantleGeophysics - seismics, Discontinuities
DS1999-0234
1999
Gaherty, J.B.Gaherty, J.B., Wang, Y., Weidner, D.J.Testing plausible upper mantle compositions using fine scale models of the410 KM discontinuity.Geophysical Research Letters, Vol. 26, No. 11, June 1, pp. 1641-4.MantleDiscontinuity
DS2001-0336
2001
Gaherty, J.B.Freybouger, M., Gaherty, J.B., Jordan, T.H.Structure of the Kaapvaal craton from surface wavesGeophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2489-92.South AfricaTectonics, Geophysics - seismics
DS200412-0600
2004
Gaherty, J.B.Gaherty, J.B.A surface wave analysis of seismic anisotropy beneath eastern North America.Geophysical Journal International, Vol. 158, 3, pp. 1053-66.United StatesGeophysics - seismics
DS200812-0740
2008
Gaherty, J.B.Mercier, J-P., Bostock, M.G., Audet, P., Gaherty, J.B., Garnero, E.J., Revenaugh, J.The teleseismic signature of fossil subduction: northwestern Canada. (part of Lithoprobe)Journal of Geophysical Research, Vol. 113, B 04308Canada, Northwest TerritoriesGeophysics - seismics
DS200912-0495
2009
Gaherty, J.B.Mercier, J.P., Bostock, M.G., Cassidy, J.F., Dueker, K., Gaherty, J.B., Garnero, E.J., Revenaugh, ZandtBody wave tomography of western Canada.Tectonophysics, Vol. 475, 2, pp. 480-492.Canada, Alberta, British Columbia, Northwest TerritoriesGeophysics - seismics
DS201012-0128
2010
Gaherty, J.B.Courtier, A.M., Gaherty, J.B., Revenaugh, J., Bostock, M.G., Gamero, E.J.Seismic anisotropy associated with continental lithosphere accretion beneath the CANOE array, northwestern Canada.Geology, Vol. 38, 10, pp. 887-890.Canada, Alberta, Northwest TerritoriesGeophysics - seismics
DS201312-0183
2013
Gaherty, J.B.Dalton, C.A., Gaherty, J.B.Seismic anisotropy in the continental crust of northwestern Canada.Geophysical Journal International, Vol. 193, 1, pp. 338-348.Canada, Northwest TerritoriesGeophysics - seismics
DS201811-2612
2018
Gai, S.S.Sun, M., Fu, X., Liu, K.H., Gai, S.S.Absence of thermal influence from the African Superswell and cratonic keels on the mantle transition zone beneath southern Africa: evidence from receiver function imaging.Earth and Planetary Science Letters, Vol. 503, pp. 108-117.Africa, South Africa, Zimbabwegeophysics - seismic

Abstract: The depths of the 410 km (d410) and 660 km (d660) discontinuities beneath southern Africa, which is presumably underlain by the lower-mantle African Superswell, are imaged in 1? radius consecutive circular bins using over 6400 P-to-S receiver functions (RFs) recorded by 130 seismic stations over a 27 yr period. When the IASP91 standard Earth model is utilized for moveout correction and time-depth conversion, a normal mantle transition zone (MTZ) thickness of 246 ± 7 km is observed, suggesting that the Superswell has no discernible effect on mantle transition zone temperature. Based on the negligible disparity of the mean MTZ thicknesses between on (246 ± 6 km) and off (246 ± 8 km) cratonic regions, we conclude that the deep Archean cratonic keels possess limited influence on MTZ thermal structure. The apparently shallower-than-normal MTZ discontinuities and the parallelism between the d410 and d660 are mostly the results of upper mantle high wave speed anomalies probably corresponding to a thick lithosphere with a mean thickness of about 245 km beneath the Kaapvaal and 215 km beneath the Zimbabwe cratons. In contradiction to conclusions from some of the previous studies, the resulting spatial distribution of the stacking amplitudes of the P-to-S converted phases at the discontinuities is inconsistent with the presence of an excessive amount of water in the MTZ and atop the d410.
DS2002-1530
2002
GaiborSpencer, R.M., Montenegro, J.L., Gaibor,Perez,MantillaThe Portovelo Zaruma mining camp: southwest Ecuador: porphyry and epithermal environments.Seg Newsletter, No. 49, April, pp. 1,8-14.EcuadorCopper, gold, Deposit - Portovelo Zaruma, R-Nivel, Muluncay
DS200512-0625
2005
Gaidamako, I.M.Levchenkov, O.A., Gaidamako, I.M., Levskii, L.K., Komarov, Yakovleva, Rizvanova, MakeevU Pb age of zircon from the Mir and 325 Let Yakutii pipes.Doklady Earth Sciences, Vol. 400, 1, pp. 99-101.Russia, YakutiaGeochronology
DS201112-0340
2011
Gaidoes, F.Gaidoes, F., Pattison, D.R.M., De Capitani, C.Toward a quantitative model of metamorphic nucleation and growth.Contributions to Mineralogy and Petrology, Vol. 162, 5, pp.975-1009.MantleContinent accretion
DS201706-1075
2017
Gaiduk, A.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.
DS1989-0458
1989
Gaiduk, V.V.Gaiduk, V.V., Shamshina, E.A.First find of pyropes in lower carboniferous conglomerates of the Ygyattinskii basin (Siberian platform)Soviet Geology and Geophysics, Vol. 30, No. 9, pp. 118-120RussiaPyropes, Mineralogy
DS1987-0020
1987
Gaidukova, V.S.Bagdasarov, Yu.M., Gaidukova, V.S.Structure and origin of magnetite from rocks on their on ore complex and carbonatites of northernSiberia.(Russian)Zap. Vses. Mineral. O-Va, (Russian), Vol. 116, No. 6, pp. 645-658RussiaCarbonatite
DS201903-0542
2019
Gailland, O.Schmiedel, T., Gailland, O., Haug, O.T., Dumazer, G., Breikreuz, C.Coulomb failure of Earth's brittle crust controls growth, emplacement and shapes of igneous sills, saucer-shaped sills and laccoliths.Earth and Planetary Science Letters, Vol. 510, pp. 161-172.MantleMagmatism

Abstract: Tabular intrusions are common features in the Earth's brittle crust. They exhibit a broad variety of shapes, ranging from thin sheet intrusions (sills, saucer-shaped sills, cone sheets), to more massive intrusions (domed and punched laccoliths, stocks). Such a diversity of intrusion shapes reflects different emplacement mechanisms caused by contrasting host rock and magma rheologies. Most current models of tabular intrusion emplacement assume that the host rock behaves purely elastically, whereas numerous observations show that shear failure plays a major role. In this study, we investigate the effects of the host rock's Coulomb properties on magma emplacement by integrating (1) laboratory models using dry Coulomb granular model hosts of variable strength (cohesion) and (2) limit analysis numerical models. Our results show that both sheet and massive tabular intrusions initiate as a sill, which triggers shear failure of its overburden along an inclined shear damage zone at a critical sill radius, which depends on the emplacement depth and the overburden's cohesion. Two scenarios are then possible: (1) if the cohesion of the overburden is significant, opening of a planar fracture along the precursory weakened shear damage zones to accommodate magma flow, leads to the formation of inclined sheets, or (2) if the cohesion of the overburden is negligible, the sill inflates and lifts up the overburden, which is dissected by several faults that control the growth of a massive intrusion. Finally, we derive a theoretical scaling that predicts the thickness-to-radius aspect ratios of the laboratory sheet intrusions. This theoretical prediction shows how sheet intrusion morphologies are controlled by a mechanical equilibrium between the flowing viscous magma and Coulomb shear failure of the overburden. Our study suggests that the emplacement of sheet and massive tabular intrusions are parts of the same mechanical regime, in which the Coulomb behavior of the Earth's brittle crust plays an essential role.
DS201904-0757
2019
Gaillard, C.Malavergegne, V., Bureau, H., Raepsaet, C., Gaillard, C., Poncet, F., Surble, M., Sifre, S., Shcheka, D., Fourdrin, S., Deldicque, C., Khodja, D., HichamExperimental constraints on the fate of H and C during planetary core-mantle differentiation. Implications for the Earth.Icarus - New York, Vol. 321, 1, pp. 473-485.Mantlecarbon

Abstract: Hydrogen (H) and carbon (C) have probably been delivered to the Earth mainly during accretion processes at High Temperature (HT) and High Pressure (HP) and at variable redox conditions. We performed HP (1-15?GPa) and HT (1600-2300°C) experiments, combined with state-of-the-art analytical techniques to better understand the behavior of H and C during planetary differentiation processes. We show that increasing pressure makes H slightly siderophile and slightly decreases the highly siderophile nature of C. This implies that the capacity of a growing core to retain significant amounts of H or C is mainly controlled by the size of the planet: small planetary bodies may retain C in their cores while H may have rather been lost in space; larger bodies may store both H and C in their cores. During the Earth's differentiation, both C and H might be sequestrated in the core. However, the H content of the core would remain one or two orders of magnitude lower than that of C since the (H/C)core ratio might range between 0.04 and 0.27.
DS201909-2040
2019
Gaillard, E.Gaillard, E., Nabyl, Z., Tuduri, J., Di Carlo, I., Melleton, J., Bailly, L.The effects of F, Cl, P and H2O on the immiscibility and rare metals partitioning between carbonate and phonolite melts.Goldschmidt2019, 1p. AbstractGlobalcarbonatite - REE

Abstract: Carbonatite and alkaline magma constitute one of the principal resources of rare metals (REE, Nb, Ti, Zr). Carbonatite rare metals enrichment is mainly considered as the result of hydrothermal or supergen processes. However, the magmatic processes linked to carbonatites genesis and differentiation are still debated and whether these processes can significantly impact on the rare metal concentrations remains unclear. Experimental studies have shown that immiscibility processes between carbonate and silicate melts can lead to both REE enrichments and depletions in carbonatites. Anionic species (F, Cl, P or S) and water may impact both melt compositions and expand the immiscibility gap. Morever, anionic species are assumed to play an important role in REE behaviour in carbonate melts [1]. Indeed, halogens may occur in carbonatites as immiscible salt melts in melt inclusions [2] and primary REE- fluoride minerals have been identified as magmatic phases in carbonatites. Such occurrences thus question on the role of salt (carbonate, phosphate, fluoride and chloride) melts in REE and other rare metals partitioning. F, Cl, P and also H2O may all significantly increase the window of primary REE enrichment in carbonatites. Here we present high pressure and high temperature experiments made in piston-cylinder (850 to 1050°C, 8kb) simulating the immiscibility between carbonate and differentiated alkaline melts. We added F, Cl, P and H2O in order to assess the effect of salts and water on the immiscibility gap and on the rare metals partitoning between carbonatite and evolved silicate melts. The partitioning data are analysed using LA-ICP-MS, nano-SIMS, FTIR and RAMAN. The characterization of rare metal partition coefficients allow to determine the relative importance of F, Cl, P and H2O on carbonatites rare metal enrichments at evolved magmatic stage.
DS200612-0327
2006
Gaillard, F.Demouchy, S., Jacobsen, S.D., Gaillard, F., Stern, C.R.Rapid magma ascent recorded by water diffusion profiles in mantle olivine.Geology, Vol. 34, 6, June pp. 429-432.Mantle, South America, ChileMagmatism, xenoliths - not specific to diamonds
DS200712-0064
2006
Gaillard, F.Behrens, H., Gaillard, F.Geochemical aspects of melts: volatiles and redox behaviour.Elements, Vol. 2, 5, October pp. 275-280.TechnologyGeochemistry
DS200912-0238
2008
Gaillard, F.Gaillard, F.Carbonatite melts and electrical conductivity in the athenosphere: the electrical conductivity of molten carbonates is higher than that of silicate minerals;Science, Vol. 322, no. 5906, Nov. 28, pp. 1363-1364.MantleCarbonatite
DS201012-0592
2010
Gaillard, F.Pommier, A., Gaillard, F., Pichavant, M.Time dependent changes of the electrical conductivity of basaltic melts with redox state.Geochimica et Cosmochimica Acta, Vol. 74, 5, pp. 1653-1671.MantleRedox
DS201412-0818
2014
Gaillard, F.Shiryeav, A.A., Gaillard, F.Local redux buffering by carbon at low pressures and the formation of moissanite natural SiC.European Journal of Mineralogy, Vol. 26, 1, pp. 53-59.TechnologyMoissanite
DS201510-1786
2015
Gaillard, F.Massuyeau, M., Gardes, E., Morizet, Y., Gaillard, F.A model for the activity of silica along the carbonatite-kimberlite-mellilitite-basanite melt compositional joint.Chemical Geology, Vol. 418, pp. 206-216.TechnologyKimberlite

Abstract: Carbon dioxide and water, being present in the Earth's mantle at concentration levels of tens to hundreds of ppm, greatly lower the peridotite solidus temperature and drastically modify the composition of produced melts. The presence of CO2 produces silica-poor, carbonate-rich liquids at the onset of melting, and these liquids shift toward silica rich compositions as the degree of melting increases. Numerous geochemical observations and experimental studies have revealed the complexity of the transition between carbonate-rich and silicate-rich melts. It is characterized by a strongly non-linear evolution and, under specific conditions, by immiscibility. To better constrain this transition, we have used the thermodynamic activity of silica as a probe of the mixing properties between molten carbonate and molten silicate. The activity of silica (aSiO2(l))aSiO2l was calculated for a large number of experimental liquids from two equilibria: olivine-orthopyroxene-melt and immiscible silicate-rich melt-carbonate-rich melt (491 data points ranging from 1 to 14 GPa and 1090 to 1800 °C). We modelled aSiO2(l)aSiO2l during incipient melting of the peridotite in presence of CO2 with a generalized Margules function. Our model reproduces well the silica activity-composition relationships of the experimental database, and can be used to predict the silica content of the melts coexisting with olivine and orthopyroxene. We show that water content and Ca/Mg ratio in the melts have an important influence on the aSiO2(l)aSiO2l. In contrast to a recent empirical model (Dasgupta et al., 2013), the analysis of the experimental database reveals that the transition from carbonate to silicate melt with decreasing depth should occur abruptly in oceanic mantle. Our model predicts that carbonatitic melts with ~ 5 wt.% SiO2 can be stabilized from ~ 150 km depth, at the onset of incipient melting by "redox melting", up to ~ 75 km, above which the liquid evolves abruptly to a carbonated silicate composition (> ~ 25 wt.% SiO2). In the cratonic mantle lithosphere, our model predicts that carbonatitic melts are prevailing up to shallow depth, and conflicts the recent model (Russell et al., 2012) of CO2-saturation triggered by orthopyroxene assimilation during kimberlite ascent.
DS201603-0402
2016
Gaillard, F.Moussallam, Y., Florian, P., Corradini, D., Morizet, Y., Sator, N., Vuilleumier, R., Guillot, B., Iacono-Marziano, G., Schmidt, B.C., Gaillard, F.The molecular structure of melts along the carbonatite-kimberlite-basalt compositional joint: CO (sub 2) and polymerisation.Earth and Planetary Science Letters, Vol. 434, pp. 129-140.TechnologyPetrology - experimental

Abstract: Transitional melts, intermediate in composition between silicate and carbonate melts, form by low degree partial melting of mantle peridotite and might be the most abundant type of melt in the asthenosphere. Their role in the transport of volatile elements and in metasomatic processes at the planetary scale might be significant yet they have remained largely unstudied. Their molecular structure has remained elusive in part because these melts are difficult to quench to glass. Here we use FTIR, Raman, 13C and 29Si NMR spectroscopy together with First Principle Molecular Dynamic (FPMD) simulations to investigate the molecular structure of transitional melts and in particular to assess the effect of CO2 on their structure. We found that carbon in these glasses forms free ionic carbonate groups attracting cations away from their usual ‘depolymerising’ role in breaking up the covalent silicate network. Solution of CO2 in these melts strongly modifies their structure resulting in a significant polymerisation of the aluminosilicate network with a decrease in NBO/Si of about 0.2 for every 5 mol% CO2 dissolved. This polymerisation effect is expected to influence the physical and transport properties of transitional melts. An increase in viscosity is expected with increasing CO2 content, potentially leading to melt ponding at certain levels in the mantle such as at the lithosphere-asthenosphere boundary. Conversely an ascending and degassing transitional melt such as a kimberlite would become increasingly fluid during ascent hence potentially accelerate. Carbon-rich transitional melts are effectively composed of two sub-networks: a carbonate and a silicate one leading to peculiar physical and transport properties.
DS201603-0403
2015
Gaillard, F.Moussallam, Y., Morizet, Y., Massuyeau, M., Laumonier, M., Gaillard, F.CO ( sub 2) solubility in kimberlite melts.Chemical Geology, Vol. 418, pp. 198-205.MantleExperimental Petrology

Abstract: Carbon dioxide is the most abundant volatile in kimberlite melts and its solubility exerts a prime influence on the melt structure, buoyancy, transport rate and hence eruption dynamics. The actual primary composition of kimberlite magma is the matter of some debate but the solubility of CO2 in kimberlitic melts is also poorly constrained due to difficulties in quenching these compositions to a glass that retains the equilibrium CO2 content. In this study we used a range of synthetic, melt compositions with broadly kimberlitic to carbonatitic characteristics which can, under certain conditions, be quenched fast enough to produce a glass. These materials are used to determine the CO2 solubility as a function of chemical composition and pressure (0.05-1.5 GPa). Our results suggest that the solubility of CO2 decreases steadily with increasing amount of network forming cations from ~ 30 wt.% CO2 at 12 wt.% SiO2 down to ~ 3 wt.% CO2 at 40 wt.% SiO2. For low silica melts, CO2 solubility correlates non-linearly with pressure showing a sudden increase from 0.1 to 100 MPa and a smooth increase for pressure > 100 MPa. This peculiar pressure-solubility relationship in low silica melts implies that CO2 degassing must mostly occur within the last 3 km of ascent to the surface having potential links with the highly explosive nature of kimberlite magmas and some of the geo-morphological features of their root zone. We present an empirical CO2 solubility model covering a large range of melt composition from 11 to 55 wt.% SiO2 spanning the transition from carbonatitic to kimberlitic at pressures from 1500 to 50 MPa.
DS201607-1309
2016
Gaillard, F.Moussallam, Y., Morizet, Y., Gaillard, F.H2O-CO2 solubility in low SiO2-melts and the unique mode of kimberlite degassing and emplacement.Earth and Planetary Science Letters, Vol. 447, pp. 151-160.Mantle, Europe, ItalyKimberlite formation, volcanism, melting

Abstract: Kimberlites are the most deep-seated magmas in the mantle and ascend to the surface at an impressive speed, travelling hundreds of kilometres in just hours while carrying a substantial load of xenolithic material, including diamonds. The ascent dynamics of these melts are buoyancy-controlled and certainly driven by outgassing of volatile species, presumably H2O and CO2, summing to concentration level of ca 15 -30 wt.% in kimberlite melts. We provide H2O -CO2 solubility data obtained on quenched glasses that are synthetic analogues of kimberlite melts (SiO2 content ranging from 18 to 28 wt.%). The experiments were conducted in the pressure range 100 to 350 MPa. While the CO2 solubility can reach 20 wt.%, we show that the H2O solubility in these low silica melts is indistinguishable from that found for basalts. Moreover, whereas in typical basalts most of the water exsolves at shallower pressure than the CO2, the opposite relationship is true for the low-SiO2 composition investigated. These data show that kimberlites can rise to depths of the upper crust without suffering significant degassing and must release large quantities of volatiles (>15 wt.%) within the very last few kilometres of ascent. This unconventional degassing path may explain the characteristic pipe, widening-upward from a ?2.5 km deep root zone, where kimberlites are mined for diamonds. Furthermore, we show that small changes in melt chemistry and original volatile composition (H2O vs. CO2) provide a single mechanism to explain the variety of morphologies of kimberlite pipes found over the world. The cooling associated to such massive degassing must freeze a large quantity of melt explaining the occurrence of hypabyssal kimberlite. Finally, we provide strong constraints on the primary volatile content of kimberlite, showing that the water content reported for kimberlite magma is mostly reflective of secondary alteration.
DS201612-2277
2016
Gaillard, F.Aulbach, S., Massuyeau, M., Gaillard, F.Origins of cratonic mantle discontinuities: a view from petrology, geochemistry and thermodynamic models.Lithos, in press available 74p.GlobalCraton

Abstract: Geophysically detectible mid-lithospheric discontinuities (MLD) and lithosphere-asthenosphere boundaries (LAB) beneath cratons have received much attention over recent years, but a consensus on their origin has not yet emerged. Cratonic lithosphere composition and origin is peculiar due to its ultra-depletion during plume or accretionary tectonics, cool present-day geothermal gradients, compositional and rheological stratification and multiple metasomatic overprints. Bearing this in mind, we integrate current knowledge on the physical properties, chemical composition, mineralogy and fabric of cratonic mantle with experimental and thermodynamic constraints on the formation and migration of melts, both below and within cratonic lithosphere, in order to find petrologically viable explanations for cratonic mantle discontinuities. LABs characterised by strong seismic velocity gradients and increased conductivity require the presence of melts, which can form beneath intact cratonic roots reaching to ~ 200-250 km depth only in exceptionally warm and/or volatile-rich mantle, thus explaining the paucity of seismical LAB observations beneath cratons. When present, pervasive interaction of these - typically carbonated - melts with the deep lithosphere leads to densification and thermochemical erosion, which generates topography at the LAB and results in intermittent seismic LAB signals or conflicting seismic, petrologic and thermal LAB depths. In rare cases (e.g. Tanzanian craton), the tops of live melt percolation fronts may appear as MLDs and, after complete lithosphere rejuvenation, may be sites of future, shallower LABs (e.g. North China craton). Since intact cratons are presently tectonomagmatically quiescent, and since MLDs produce both positive and negative velocity gradients, in some cases with anisotropy, most MLDs may be best explained by accumulations (metasomes) of seismically slow minerals (pyroxenes, phlogopite, amphibole, carbonates) deposited during past magmatic-metasomatic activity, or fabric inherited from cratonisation. They may accumulate as layers at, or as subvertical veins above, the depth at which melt flow transitions from pervasive to focussed flow at the mechanical boundary layer, causing azimuthal and radial anisotropy. Thermodynamic calculations investigating the depth range in which small-volume melts can be produced relative to the field of phlogopite stability and the presence of MLDs show that phlogopite precipitates at various pressures as a function of age-dependent thermal state of the cratonic mantle, thus explaining variable MLD depths. Even if not directly observed, such metasomes have been shown to be important ingredients in small-volume volatile-rich melts typically penetrating cratonic lithospheres. The apparent sparseness of evidence for phlogopite-rich assemblages in the mantle xenolith record at geophysically imaged MLD depths, if not due to preferential disaggregation in the kimberlite or alteration, may relate to vagaries of both kimberlite and human sampling.
DS201909-2065
2019
Gaillard, F.Nabyl, Z., Massuyeau, M., Gaillard, F., Tuduri, J., Iacono-Marziano, G., Rogerie, G., Le Trong, E., Di Carlo, I., Melleton, J., Bailly, L.REE-rich carbonatites immiscible with phonolitic magma.Goldschmidt2019, 1p. AbstractGlobalcarbonatite - REE

Abstract: uncommon type of magmatic rocks dominates by carbonate, are broadly enriched in rare earth elements (REE) relative to the majority of igneous silicate rocks. While more than 500 carbonatites are referenced worldwide [1], only a few contain economic REE concentrations that are widely considered as resulting from late magmatic-hydrothermal or supergene processes. Magmatic pre-enrichment, linked to the igneous processes at the origin of carbonatites, are, however, likely to contribute to the REE fertilisation. Field observations [1] and experimental surveys [2, 3] suggest that a large part of the carbonatite melts can be produced as immiscible liquids with silicate magmas. Experimental constraints reveals that such immiscibility processes can lead to both REE enrichments and depletions in carbonatites [2, 3], making the magmatic processes controlling REE enrichments unclear. Here we present results of high-pressure and hightemperature experiments, simultaneously addressing crystal fractionation of alkaline magmas and immiscibility between carbonate and silicate melts. The experimental data reveal that the degree of differentiation, controlling the chemical composition of alkaline melts is a key factor ruling the REE concentration of the coexisting immiscible carbonatites. The parameterization of the experimental data together with the compilation of geochemical data from various alkaline provinces show that REE concentrations similar to those of highly REE enriched carbonatites (?REE > 30000 ppm) can be produced by immiscibility with phono-trachytic melt compositions, while more primitive alkaline magma can only be immiscible with carbonatites that are not significantly enriched in REE.
DS202006-0940
2020
Gaillard, F.Nabyl, Z., Massuyeau, M., Gaillard, F., Tuduri, J., Iacono-Marziano, G., Rogerie, G., Le Trong, E., Di Carlo, I., Melleton, J., Bailly, L.A window in the course of alkaline magma differentiation conducive to immiscible REE-rich carbonatites.Geochimica et Cosmochimica Acta, in press available 57p. PdfMantlecarbonatite

Abstract: Rare earth element (REE) enrichments in carbonatites are often described as resulting from late magmatic-hydrothermal or supergene processes. However, magmatic pre-enrichment linked to the igneous processes at the origin of carbonatites are likely to contribute to the REE fertilisation. Experimental constraints reveals that immiscibility processes between carbonate and silicate melts can lead to both REE enrichments and depletions in carbonatites making the magmatic processes controlling REE enrichments unclear. We link REE contents of carbonatites to the magmatic stage at which carbonatites are separated from silicate magma in their course of differentiation. We present results of experiments made at pressure and temperature conditions of alkaline magmas and associated carbonatites differentiation (0.2-1.5 GPa; 725-975?°C; FMQ to FMQ?+?2.5), simultaneously addressing crystal fractionation of alkaline magmas and immiscibility between carbonate (calcio-carbonate type) and silicate melts (nephelinite to phonolite type). The experimental data shows that the degree of differentiation, controlling the chemical composition of alkaline melts, is a key factor ruling the REE concentration of the coexisting immiscible carbonate melts. In order to predict carbonate melt REE enrichments during alkaline magma differentiation, we performed a parameterisation of experimental data on immiscible silicate and carbonate melts, based exclusively on the silica content, the alumina saturation index and the alkali/alkaline-earth elements ratio of silicate melts. This parameterisation is applied to more than 1600 geochemical data of silicate magmas from various alkaline provinces (East African Rift, Canary and Cape Verde Islands) and show that REE concentrations of their potential coeval carbonatite melts can reach concentration ranges similar to those of highly REE enriched carbonatites (?REE?>?30 000?ppm) by immiscibility with phonolitic/phono-trachytic melt compositions, while more primitive alkaline magmas can only be immiscible with carbonatites that are not significantly enriched in REE.
DS202009-1643
2020
Gaillard, F.Nabyl, Z., Massuyeau, M.,Gaillard, F., Tuduri, J., Gregory, G-M., Trong, E., Di Carlo, I., Melleton, J., Bailly, L. A window in the course of alkaline magma differentiation conducive to immiscible REE-rich carbonatite.Geochimica et Cosmochimica Acta, Vol. 282, pp. 297-323.Africa, East Africacarbonatites

Abstract: Rare earth element (REE) enrichments in carbonatites are often described as resulting from late magmatic-hydrothermal or supergene processes. However, magmatic pre-enrichment linked to the igneous processes at the origin of carbonatites are likely to contribute to the REE fertilisation. Experimental constraints reveals that immiscibility processes between carbonate and silicate melts can lead to both REE enrichments and depletions in carbonatites making the magmatic processes controlling REE enrichments unclear. We link REE contents of carbonatites to the magmatic stage at which carbonatites are separated from silicate magma in their course of differentiation. We present results of experiments made at pressure and temperature conditions of alkaline magmas and associated carbonatites differentiation (0.2-1.5 GPa; 725-975?°C; FMQ to FMQ?+?2.5), simultaneously addressing crystal fractionation of alkaline magmas and immiscibility between carbonate (calcio-carbonate type) and silicate melts (nephelinite to phonolite type). The experimental data shows that the degree of differentiation, controlling the chemical composition of alkaline melts, is a key factor ruling the REE concentration of the coexisting immiscible carbonate melts. In order to predict carbonate melt REE enrichments during alkaline magma differentiation, we performed a parameterisation of experimental data on immiscible silicate and carbonate melts, based exclusively on the silica content, the alumina saturation index and the alkali/alkaline-earth elements ratio of silicate melts. This parameterisation is applied to more than 1600 geochemical data of silicate magmas from various alkaline provinces (East African Rift, Canary and Cape Verde Islands) and show that REE concentrations of their potential coeval carbonatite melts can reach concentration ranges similar to those of highly REE enriched carbonatites (?REE?>?30 000?ppm) by immiscibility with phonolitic/phono-trachytic melt compositions, while more primitive alkaline magmas can only be immiscible with carbonatites that are not significantly enriched in REE.
DS202010-1862
2020
Gaillard, F.Morizet, Y., Larre, C., Di Carlo, I., Gaillard, F.High S and high CO2 contents in haplokimberlite: an experimental and Raman spectroscopic study.Mineralogy and Petrology, Vol. 114, pp. 363-373. pdfMantlemelting

Abstract: Sulfur is an important element present in natural kimberlites and along with CO2, S can play a role in the kimberlite degassing. We have investigated experimentally the change in S content and CO2 solubility in synthetic kimberlitic melts in response to a range of pressure (0.5 to 2.0 GPa) and temperature (1500 to 1525 °C). Several initial S concentrations were investigated ranging from 0 to 24000 ppm. The dissolved CO2 and S were determined by Raman spectroscopy and Electron Probe Micro-Analyses. Under the investigated oxidizing conditions (?FMQ?+?1), S is dissolved in the glass only as S6+ forming sulfate molecular groups (SO42?). The measured S concentration in the glasses increases from 2900 to 22000 ppm. These results suggest that the experimental conditions were below saturation with respect to S and that the S solubility is higher than 22000 ppm for kimberlitic melts; regardless of the experimental conditions considered here. CO2 is dissolved as CO32? molecular groups. The CO2 solubility ranges from 3.0 to 11.3 wt% between 0.5 and 2.0 GPa. CO2 solubility is not affected by the presence of S; which suggests that SO42? and CO32? clusters have two distinct molecular environments not interacting together. This result implies that both CO2 and S are efficiently transported by kimberlitic melt from the upper mantle towards the atmosphere.
DS202102-0190
2019
Gaillard, F.Gaillard, F., Sator, N., Guillot, B., Massuyeau, M.The link between the physical and chemical properties of carbon-bearing melts and their application for geophysical imaging of Earth's mantleResearchgate , DOI: 10.1017/ 9781108677950.007 26p. Pdfmantlecarbon

Abstract: Significant investment in new capacities for experimental research at high temperatures and pressures have provided new levels of understanding about the physical properties of carbon in fluids and melts, including its viscosity, electrical conductivity, and density. This chapter reviews the physical properties of carbon-bearing melts and fluids at high temperatures and pressures and highlights remaining unknowns left to be explored. The chapter also reviews how the remote sensing of the inaccessible parts of the Earth via various geophysical techniques - seismic shear wave velocity, attenuation, and electromagnetic signals of mantle depths - can be reconciled with the potential presence of carbon-bearing melts or fluids.
DS202102-0207
2021
Gaillard, F.Massuyeau, M., Gardes, E., Rogerie, G., Aulbach, S., Tappe, S., Le Trong, E., Sifre, D., Gaillard, F.MAGLAB: A computing platform connecting geophysical signatures to melting processes in Earth's mantle.Physics of the Earth and Planetary Interiors, doi.org/10.1016/ j.pepi.2020.106638 51p. PdfMantlegeophysics - magnetics

Abstract: Decompression melting of the upper mantle produces magmas and volcanism at the Earth's surface. Experimental petrology demonstrates that the presence of CO2 and H2O enhances peridotite melting anywhere within the upper mantle down to approximately 200-300?km depth. The presence of mantle melts with compositions ranging from carbonate-rich to silicate-rich unavoidably affects the geophysical signals retrieved from Earth's mantle. Geochemical investigations of erupted intraplate magmas along with geophysical surveys allow for constraining the nature and volume of primary melts, and a sound formalism is required to integrate these diverse datasets into a realistic model for the upper mantle including melting processes. Here, we introduce MAGLAB, a model developed to calculate the composition and volume fraction of melts in the upper mantle, together with the corresponding electrical conductivity of partially molten mantle peridotites at realistic pressure-temperature conditions and volatile contents. We use MAGLAB to show how the compositions of intraplate magmas relate to variations in lithosphere thickness. Progressive partial melting of a homogeneous peridotitic mantle source can in theory create the diversity of compositions observed among the spectrum of intraplate magma types, with kimberlite melts beneath thick continental shields, alkaline magmas such as melilitite, nephelinite and basanite beneath thinner continents and relatively old plus thick oceanic lithospheres, and ‘regular’ basalts beneath the youngest and thinnest oceanic lithospheres as well as beneath significantly thinned continental lithospheres. MAGLAB calculations support recent experimental findings about the role of H2O in the upper mantle on producing primary kimberlitic melts in addition to CO2. We demonstrate the robustness of MAGLAB calculations by reproducing the compositions of erupted melts as well as associated mantle electrical conductivities beneath the Society hotspot in the Pacific Ocean. A comparison of our simulations with magnetotelluric surveys at various oceanic settings shows that the heterogeneities in electrical conductivity of Earth's upper mantle are related to variations in volatile content via the presence of small (generally <<1?wt%) and heterogeneously distributed fractions of CO2-H2O-bearing melts.
DS202104-0570
2021
Gaillard, F.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
DS202203-0357
2021
Gaillard, F.Molle, V., Gaillard, F., Nabyl, Z., Tuduri, J., Di Carlo, I., Erdmann, S.Crystallisation sequence of a REE-rich carbonate melt: an experimental approach. Bastanaesite, natrocarbonatiteComptes Rendus Geoscience, Vol. 353, no S2, pp. 217-231.Globalcarbonatite

Abstract: Carbonatites host Earth’s main REE deposits, with bastnaesite (LREE)CO F being the main economic REE-bearing mineral. However, bastnaesite mineralisation processes are debated between hydrothermal or magmatic origin. This study aims to assess if bastnaesite can be magmatic, and to characterise the REE behaviour during carbonatite crystallisation. Crystallisation experiments have been performed from 900 to 600 °C at 1 kbar, on a REE-rich calciocarbonatitic composition. REE-bearing calcite is the dominant crystallising mineral, driving the residual melt towards natrocarbonatitic compositions. Both halogens (i.e., Cl and F) and water decrease the temperature of calcite saturation. REE are slightly incompatible with calcite: for all REE, partition coefficients between carbonate melt and calcite are comprised between 1 and 11, and increase with temperature decrease. Britholite (REE, Ca) (Si,P)O) (F,OH) crystallises at high temperatures (700-900 °C), while pyrochlore (Ca,Na,REE) NbO (OH,F) crystallises at low temperatures (600-700 °C), as well as REE-rich apatite (600-650 °C). No bastnaesite is found in crystallisation experiments. We thus performed a bastnaesite saturation experiment at 600 °C. The bastnaesite-saturated melt contains 20 wt% of REE: such magmatic saturation is unlikely to happen in nature. Textural evidences imply a Na, Cl, REE-rich fluid at high temperatures and hydrous conditions. We propose that fluids are the main mineralising agent for bastnaesite at hydrothermal stage (600 °C).
DS202203-0358
2021
Gaillard, F.Nabyl, Z., Gaillard, F., Turduri, J., Di Carlo, I.No direct effect of F, Cl, and P on REE partitioning between carbonate and alkaline silicate melts.Comptes Rendus Geoscience, Vol. 353, no S2, pp. 233-272. pdfGlobalcarbonatites

Abstract: This study presents new insights into the effects of halogens (F and Cl) and phosphorous (P) on rare earth element (REE) partitioning between carbonatite and alkaline silicate melts. F, Cl and P are elements that are abundant in carbonatites and alkaline magmatic systems and they are considered to play an important role on the REE behaviour. Nonetheless, their effect on REE partitioning between carbonate and alkaline silicate melts has not yet been constrained. Here we present new experimental data on REE partitioning between carbonate and alkaline silicate melts doped in F, Cl and P, in order to (1) test the Nabyl et al. [2020] REE partitioning model in F-, Cl- and P-rich systems, and (2) identify the possible role of F, Cl and P in carbonate melt REE enrichments during alkaline–carbonatite magma differentiation. The experiments were performed at 850–1050 °C and 0.8 GPa using piston-cylinder devices. Starting materials consisted of carbonatite and phonolite compositions doped in F, Cl and P. The experimental results show that REE partitioning is similar in F-Cl-P-rich and -poor systems. The silicate melt composition and its molecular structure (i.e. SiO contents, the alumina saturation index and the alkali/alkaline-earth element ratio), which have already been identified as controlling REE partitioning in F-, Cl- and P-poor systems, still operate in doped systems. No direct effect of the F, Cl or P melt concentrations on REE partitioning has been identified. We also propose an application to natural systems.
DS1996-0395
1996
Gaillardet, J.Dupre, B., Gaillardet, J., Rousseau, D., Allegre, C.J.Major and trace elements of river borne material: The Congo BasinGeochimica et Cosmochimica Acta, Vol. 60, No. 8, April pp. 1301-1321.Central African RepublicCongo River Basin, Black Rivers, weathering
DS2002-1056
2002
Gaillardet, J.Millot, R., Gaillardet, J., Dupre, B., Allegre, C.J.The global control of silicate weathering rates and the coupling of physical erosion: new insights from riversEarth and Planetary Science Letters, Vol.196, 1-2, Feb.28, pp.83-98.Northwest Territories, Alberta, Manitoba, Ontario, QuebecGeomorphology
DS200412-1313
2004
Gaillardet, J.Millot, R., Allegre, C.J., Gaillardet, J., Roy, S.Lead isotopic systematics of major river sediments: a new estimate of the Pb isotopic composition of the Upper Continental CrustChemical Geology, Vol. 203, 1-2, Jan. 15, pp. 75-90.MantleGeochronology
DS201312-0291
2012
Gaillardet, J.Galvez, M.E., Gaillardet, J.Historical constraints on the origins of the carbon cycle concept.Comptes Rendus Geoscience, Vol. 344, pp. 549-567.MantleCarbon cycle
DS201112-1098
2011
GaillouWalter, M.J., Kohn, Arajuo, Bulanova, Smith, Gaillou, Wang, Steele, ShireyDeep mantle cycling of oceanic crust: evidence from diamonds and their mineral inclusions.Science, Vol. 334, 6052, pp. 51-52.MantleDiamond inclusions
DS200812-0376
2007
Gaillou, E.Gaillou, E., Post, J.E.An examination of the Napoleon diamond necklace.Gems & Gemology Lab Notes, Vol. 43, 4, Winter pp. 352-357.TechnologyType 1a and 11a diamonds
DS201012-0214
2010
Gaillou, E.Gaillou, E., Post, J.E., Bassim, N.D., Zaitsev, A.M., Rose, T., Fries, M.D., Stroud, R.M., Steele, A., Butler, J.E.Spectroscopic and microscopic characterizations of color laminae in natural pink diamonds.Diamond and Related Materials, Vol. 19, 10, pp. 1207-1220.TechnologySpectroscopy
DS201012-0215
2010
Gaillou, E.Gaillou, E., Rost, D., Post, J., Butler, J.Quantifying boron in natural type IIb blue diamonds.Goldschmidt 2010 abstracts, abstractTechnologyDiamond morphology
DS201012-0216
2010
Gaillou, E.Gaillou, E., Wang, W., Post, J.E., King, J.M., Butler, J.E., Collins, A.T., Moses, T.M.The Wittelsbach-Graff and Hope diamonds: not cut from the same rough.Gems & Gemology, Vol. 46, 2, pp. 80-88.TechnologyDiamonds notable
DS201112-0341
2011
Gaillou, E.Gaillou, E., Post, J.E., Butler, J.E.On the pecularities of Australian and Venezuelan pink diamonds: influence of the geologic settings.Goldschmidt Conference 2011, abstract p.882.Australia, South America, VenezuelaArgyle, Santa Elena, high thermal events
DS201212-0096
2012
Gaillou, E.Bulanova, G.P., Marks, A., Smith, C.B., Kohn, S.C., Walter, M.J., Gaillou, E., Shiry, S.B., Trautman, R., Griffin, B.J.Diamonds from Sese and Murowa kimberlites ( Zimbabwe) - evidence of extreme peridotitic lithosphere depletion and Ti-REE metasomatism.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, ZimbabweDeposit - Sese, Murowa
DS201212-0225
2012
Gaillou, E.Gaillou, E.,Post, J.E., Rost, D., Butler, J.E.Boron in natural type 11b blue diamonds: chemical and spectroscopic measurements.American Mineralogist, Vol. 97, pp. 1-18.TechnologyBlue diamond
DS201412-0260
2014
Gaillou, E.Gaillou, E., Rossman, G.R.Color in natural diamonds: the beauty of defects.Rocks and Minerals, Jan-Feb. pp. 66-75.TechnologyDiamond - colour
DS201503-0144
2015
Gaillou, E.Gaillou, E., Post, J.E., Byne, K.S., Butler, J.E.Study of the Blue Moon diamond. ( from Cullinan)Gems & Gemology, Vol. 50, 4, winter 2014, 9p.Africa, South AfricaDiamonds notable

Abstract: The Blue Moon diamond, discovered in January 2014 at the historic Cullinan mine in South Africa, is of significance from both trade and scientific perspectives. The 29.62 ct rough yielded a 12.03 ct Fancy Vivid blue, Internally Flawless gem. The authors were provided the opportunity to study this rare diamond at the Smithsonian Institution before it went on exhibit at the Natural History Museum of Los Angeles County. Infrared spectroscopy revealed that the amount of uncompensated boron in the diamond was 0.26 ± 0.04 ppm, consistent with measurements of several large type IIb blue diamonds previously studied. After exposure to short-wave ultraviolet light, the Blue Moon displayed orange-red phosphorescence that remained visible for up to 20 seconds. This observation was surprising, as orange-red phosphorescence is typically associated with diamonds of Indian origin, such as the Hope and the Wittelsbach-Graff. Time-resolved phosphorescence spectra exhibited peaks at 660 and 500 nm, typical for natural type II blue diamonds. As with most natural diamonds, the Blue Moon showed strain-induced birefringence.
DS201605-0897
2016
Gaillou, E.Schoor, M., Boulliard, J.C., Gaillou, E., Duparc, O.H., Esteve, I., Baptiste, B., Rondeau, B., Fritsch, E.Plastic deformation in natural diamonds: rose channels associated to chemical twinning.Diamond and Related Materials, in press available 14p.TechnologyDiamond morphlogy
DS201608-1434
2016
Gaillou, E.Post, J.E., Gaillou, E., Butler, J.E., Byrne, K.S.Investigations into luminescence properties and compositions of colored diamonds.GSA Annual Meeting, Abstract, 1p.TechnologyLuminescence

Abstract: The Smithsonian’s National Gem Collection includes the Hope Diamond and an assortment of other significant fancy-colored diamonds, providing a unique opportunity to conduct detailed and sustained studies on an unprecedented selection of these rare and valuable stones. We present an overview and recent results from our work on pink, blue and chameleon diamonds. Boron causes the blue color of the Hope Diamond and other type IIb diamonds, but scarcity, high value, and the low concentration of B has inhibited B analyses of natural IIb diamonds. We used FTIR and ToF-SIMS to measure concentrations and distributions of B in the Hope and other blue diamonds. ToF-SIMS analyses gave spot B concentrations as high as 8.4 ± 1.1 ppm for the Hope Diamond to less than 0.08 ppm in other blue diamonds and revealed strong zoning of B in some diamonds, which was confirmed by mapping using synchrotron FTIR. Boron is also responsible for the phosphorescence emissions of IIb diamonds, at 660 nm and 500 nm; the emissions are likely caused by donor-acceptor pair recombination processes involving B and other defects. Approximately 50 type I natural pink diamonds were compared using UV-Vis, FTIR, and CL spectroscopies. All stones exhibit pink color zoning, ~1µm thick [111] lamellae, in otherwise colorless diamond. The pink diamonds fall into two groups: 1) those from Argyle in Australia and Santa Elena in Venezuela, and 2) those from other localities. TEM imaging from FIB sections revealed that twinning is the likely mechanism by which plastic deformation is accommodated for the pink diamonds. The deformation creates new centers, including the one responsible for the pink color, which remains unidentified. The differences in the plastic deformation features for the two groups might correlate to the particular geologic conditions under which the diamonds formed. Fluorescence and thermoluminescence experiments on natural chameleon diamonds reveal that an emission band, peaking near 556nm, may be stimulated via a number of different mechanisms. We discuss the implications of our observations for the electronic structure of the 556nm-fluorescing defect center, and the connections to the unidentified color center responsible for chameleon color changes.
DS201610-1900
2016
Gaillou, E.Post, J.E., Gaillou, E., Butler, J.E., Byrne, K.S.Investigations into the luminescence properties and compositions of colored diamonds. ( blue and pink)GSA Annual Meeting, 1/2p. abstractTechnologyColoured diamonds

Abstract: The Smithsonian’s National Gem Collection includes the Hope Diamond and an assortment of other significant fancy-colored diamonds, providing a unique opportunity to conduct detailed and sustained studies on an unprecedented selection of these rare and valuable stones. We present an overview and recent results from our work on pink, blue and chameleon diamonds. Boron causes the blue color of the Hope Diamond and other type IIb diamonds, but scarcity, high value, and the low concentration of B has inhibited B analyses of natural IIb diamonds. We used FTIR and ToF-SIMS to measure concentrations and distributions of B in the Hope and other blue diamonds. ToF-SIMS analyses gave spot B concentrations as high as 8.4 ± 1.1 ppm for the Hope Diamond to less than 0.08 ppm in other blue diamonds and revealed strong zoning of B in some diamonds, which was confirmed by mapping using synchrotron FTIR. Boron is also responsible for the phosphorescence emissions of IIb diamonds, at 660 nm and 500 nm; the emissions are likely caused by donor-acceptor pair recombination processes involving B and other defects. Approximately 50 type I natural pink diamonds were compared using UV-Vis, FTIR, and CL spectroscopies. All stones exhibit pink color zoning, ~1µm thick [111] lamellae, in otherwise colorless diamond. The pink diamonds fall into two groups: 1) those from Argyle in Australia and Santa Elena in Venezuela, and 2) those from other localities. TEM imaging from FIB sections revealed that twinning is the likely mechanism by which plastic deformation is accommodated for the pink diamonds. The deformation creates new centers, including the one responsible for the pink color, which remains unidentified. The differences in the plastic deformation features for the two groups might correlate to the particular geologic conditions under which the diamonds formed. Fluorescence and thermoluminescence experiments on natural chameleon diamonds reveal that an emission band, peaking near 556nm, may be stimulated via a number of different mechanisms. We discuss the implications of our observations for the electronic structure of the 556nm-fluorescing defect center, and the connections to the unidentified color center responsible for chameleon color changes.
DS201703-0442
2017
Gaillou, E.Zubkov, V.I., Solomnikova, A.V., Post, J.E., Gaillou, E., Butler, J.E.Characterization of electronic properties of natural type 11b diamonds.Diamond and Related Materials, Vol. 72, pp. 87-93.TechnologyDiamonds - type 11b

Abstract: Precision admittance spectroscopy measurements were carried out over wide temperature and frequency ranges for a set of natural single crystal type IIb diamond samples. Peaks of conductance spectra vs. temperature and frequency were used to compute the Arrhenius plots, and activation energies were derived from these plots. The capacitance-voltage profiling was used to estimate the majority charge carrier concentration and its distribution into depth of the samples. Apparent activation energies between 315 and 325 meV and the capture cross section of about 10? 13 cm2 were found for samples with uncompensated boron concentrations in the range of 1 to 5 × 1016 cm? 3 (0.06-0.3 ppm). The obtained boron concentrations are in good coincidence with FTIR results for the samples. Also, a reason for the difference between the observed admittance activation energy and the previously reported ionization energy for the acceptor boron in diamond (0.37 eV) is proposed.
DS201705-0827
2017
Gaillou, E.Gaillou, E., Rossman, G.R.On the Beauty of Defects.lithographie.org, No. 19, pp. 40-53.TechnologyBook - diamond colour

Abstract: Extensive study has shown that these inclusions contain mantle-derived fluids (e.g. Navon et al., 1988, Izraeli et al., 2001, 2004 Tomlinson et al., 2009; Logvinova et al., 2011; Zedgenizov et al., 2011; Smith et al., 2012, Smith et al., 2015 Howell et al., 2012b Howell et al., , 2013 Weiss et al., 2013 Weiss et al., , 2015 Rakovan et al., 2014; Smit et al., in press), Here we use the term 'milky' to describe diamonds that contain zones of opalescent to brown or grey opaque appearance (Gaillou and Rossman, 2014). The exact cause of this opacity is yet to be defined, and forms the purpose of this paper.
DS201809-2014
2018
Gaillou, E.Daver, L., Bureau, H., Gaillou, E., Ferraris, C., Bouillard, J-C., Cartigny, P., Pinti, D.L.In situ analysis of inclusions in diamonds from collections.Goldschmidt Conference, 1p. AbstractGlobaldiamond inclusions

Abstract: Diamonds represent one of the few witnesses of our planet interior. They are mainly formed in the first 200 km of the lithospheric mantle, and, more rarely from the transition zone to 700 km deep. Diamonds contain a lot of information about global evolution, however their mode of formation remains poorly understood. Recent studies in high-pressure mineralogy suggest that diamonds precipitate from oxidized metasomatic fluids. The study of inclusions trapped in diamonds may provide precise information on composition, pressure, temperature and redox conditions. The aim of this study is to use the inclusions trapped in diamond as probes of the deep cycling of volatiles (C, H, halogens). Therefore, we investigate inclusions in diamonds with a systematic study of diamonds from collections. We selected 73 diamonds from three museums: National Museum of Natural History, School of Mines and Sorbonne University. The selected diamonds are studied with the help of a large range of in situ methods: RAMAN and FTIR spectrometry and X-Ray Diffraction. These analyses allow us to identify the nature of the different inclusions without damaging the gems. First results indicate silicate minerals inclusions as pyrope garnet, olivine and enstatite pyroxene. This assemblage is typical of peridotitic-type diamonds in the lithosphere.
DS201812-2785
2018
Gaillou, E.Bulanova, G.P., Speich, L. Smith, C.B., Gaillou, E., Koln, S.C., Wibberley, E., Chapman, J.G., Howell, D., Davy, A.T.Argyle deposit: The unique nature of Argyle fancy diamonds: internal structure, paragenesis, and reasons for color.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 169-190.Australia, western Australiadeposit - Argyle
DS201905-1032
2014
Gaillou, E.Gaillou, E., Rossman, G.R.Color in natural diamonds .. The beauty of defects. Note date ***Rocks & Minerals, 12p.Globaldiamond colour

Abstract: In its pure form, diamond is colorless. However, in nature (or even when made in laboratories), diamonds are never composed of 100 percent carbon atoms. Even colorless diamonds will contain some defects: missing carbon atoms or containing trace amounts of nitrogen or hydrogen, for example. When present in certain atomic arrangements and concentrations, most minor components cause absorption of specific wavelengths of light, giving rise to color. The color in diamond is not source specific, even if some mines are known to produce more of certain colors, such as blue diamonds from the Premiere mine in South Africa, or brown and pink diamonds from the Argyle mine in Australia. Virtually every single diamond mine could produce any kind of colored diamond. At auction, record prices for gems are currently held by pink and blue diamonds: for example, $2,155,332 per carat for a 24.78-carat Fancy vivid pink diamond (sold at Sotheby's in 2010) and $1.8 million per carat for a 5.3-carat Fancy deep blue diamond (sold at Bonhams in London in April 2013).
DS201606-1093
2015
Gain, S.Howell, D., Griffin, W.L., Yang, J., Gain, S., Stern, R.A., Huang, J-X., Jacob, D.E., Xu, X., Stokes, A.J., O'Reilly, S.Y., Pearson, N.J.Diamonds in ophiolites: contamination or a new diamond growth environment?Earth and Planetary Science Letters, Vol. 430, pp. 284-295.Asia, TibetLuobusa Massif Type Iib

Abstract: For more than 20 years, the reported occurrence of diamonds in the chromites and peridotites of the Luobusa massif in Tibet (a complex described as an ophiolite) has been widely ignored by the diamond research community. This skepticism has persisted because the diamonds are similar in many respects to high-pressure high-temperature (HPHT) synthetic/industrial diamonds (grown from metal solvents), and the finding previously has not been independently replicated. We present a detailed examination of the Luobusa diamonds (recovered from both peridotites and chromitites), including morphology, size, color, impurity characteristics (by infrared spectroscopy), internal growth structures, trace-element patterns, and C and N isotopes. A detailed comparison with synthetic industrial diamonds shows many similarities. Cubo-octahedral morphology, yellow color due to unaggregated nitrogen (C centres only, Type Ib), metal-alloy inclusions and highly negative View the MathML source?C13 values are present in both sets of diamonds. The Tibetan diamonds (n=3n=3) show an exceptionally large range in View the MathML source?N15 (?5.6 to +28.7‰+28.7‰) within individual crystals, and inconsistent fractionation between {111} and {100} growth sectors. This in contrast to large synthetic HPHT diamonds grown by the temperature gradient method, which have with View the MathML source?N15=0‰ in {111} sectors and +30‰+30‰ in {100} sectors, as reported in the literature. This comparison is limited by the small sample set combined with the fact the diamonds probably grew by different processes. However, the Tibetan diamonds do have generally higher concentrations and different ratios of trace elements; most inclusions are a NiMnCo alloy, but there are also some small REE-rich phases never seen in HPHT synthetics. These characteristics indicate that the Tibetan diamonds grew in contact with a C-saturated Ni-Mn-Co-rich melt in a highly reduced environment. The stable isotopes indicate a major subduction-related contribution to the chemical environment. The unaggregated nitrogen, combined with the lack of evidence for resorption or plastic deformation, suggests a short (geologically speaking) residence in the mantle. Previously published models to explain the occurrence of the diamonds, and other phases indicative of highly reduced conditions and very high pressures, have failed to take into account the characteristics of the diamonds and the implications for their formation. For these diamonds to be seriously considered as the result of a natural growth environment requires a new understanding of mantle conditions that could produce them.
DS201606-1090
2016
Gain, S.E.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?
DS201910-2258
2019
Gain, S.E.Gain, S.E., Griffin, W.L., Saunders, M., Shaw, J.A., Toledo, V.A showcase of analytical techniques: native vanadium in hibonite and chromium in corundum: ultra-high contents under reducing conditions. Two posters Shefa Gems Microscopy and Microanalysis ( M&M)Co. Conference, Sept. 9, posters 1 p. eachEurope, Israeldeposit - Kishon

Abstract: The Microscopy and Microanalysis (M&M) conference in Portland Oregon, USA is one of the biggest microscopy conferences in the world and this year it hosted its largest meeting in history with over 3,300 participants, up to 20 parallel sessions and over 600 posters. The two posters were presented by Sarah E.M. Gain who is from the University of Western Australia where she trains and supports researchers in Microscopy, Characterisation and Microanalysis. Sarah discussed some of the unique gem material collected from Shefa Gems’ exploration activity in the Kishon Mid Reach and Rakefet Magmatic Complex, analysed using a range of microscopy and microanalysis techniques. She also discussed the scientific importance of this material.The first poster looked at hibonite (a Ca-Al-oxide) with inclusions of vanadium metal. The second poster looked at, Cr corundum (ruby), which is unusual due to the extremely high Cr levels and the inclusions of Cr metal.
DS201505-0246
2015
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Toledo, V., O'Reilly, S.Y., Jacob, D., Pearson, N.J.Corundum, moissanite and super reducing conditions in the upper mantle beneath the lower ( southern) Galilee ( Israel).Israel Geological Society, 1p.posterEurope, IsraelMineralogy
DS201603-0381
2016
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Adams, D., Huang, J-X., Saunders, M.,Toledo, V., Pearson, N.J., O'Reilly, S.Y.Heaven on Earth: tistarite ( Ti203) and other nebular phases in corundum aggregates from Mt. Carmel volcanic rocks.Israel Geological Society, pp. 85-86. abstractEurope, IsraelMoissanite

Abstract: This ending talk, focused on the ongoing cooperative research of Prof. Griffin and his team at Macquarie University and Shefa Yamim, since January 2014, highlighting unique corundum species characteristics. Preliminary results of this research were presented in the IGS Annual Meeting of 2015, whereas this year Prof. Griffin has shared innovative findings only microscopically tracked within titanium-rich corundum aggregates. One of the more abundant minerals is Tistarite (Ti2O3), previously known only as a single grain in a primitive type of meteorite (!). An article has been submitted to a scientific journal detailing this first terrestrial occurrence. Several other minerals are common in meteorites, but unknown or extremely rare on Earth. About half of these minerals are unknown to science, and will be described as new minerals in the scientific literature. The first of these is a Titanium-Aluminium-Zirconium oxide, informally known as TAZ; it will be submitted to the International Mineralogical Association for recognition as a new mineral, ShefaTAZite. Using state of the art technologies such as Thermal Ionisation Mass Spectrometry (TIMS) and Electron Microscopy Facility (EMF) that has three scanning electron microscopes, all with EBSD capability, and a transmission electron microscope - Prof. Griffin revealed spectacular imagery of minerals and rare compounds associated with titanium rich corundum aggregates.
DS201603-0382
2016
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Adams, D., Toledo, V., Pearson, N.J., O'Reilly, S.Y.Deep-Earth methane, mantle dynamics and mineral exploration: insights from northern Israel, southern Tibet and Kamchatka.Israel Geological Society, pp. 87-88. abstractEurope, Israel, TibetMoissanite
DS201610-1865
2016
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Adams, D.T., Huang, J-X., Saunders, M., Toledo, V., Pearson, N.J., O'Reilly, S.Y.First terrestrial occurrence of tistarite ( Ti2O3): ultra-low oxygen fugacity in the upper mantle beneath Mount Carmel, Israel.Geology, Vol. 44, 10, pp. 815-818.Europe, IsraelMoissanite

Abstract: The minimum oxygen fugacity (fO2) of Earth's upper mantle probably is controlled by metal saturation, as defined by the iron-wüstite (IW) buffer reaction (FeO ? Fe + O). However, the widespread occurrence of moissanite (SiC) in kimberlites, and a suite of super-reduced minerals (SiC, alloys, native elements) in peridotites in Tibet and the Polar Urals (Russia), suggest that more reducing conditions (fO2 = 6-8 log units below IW) must occur locally in the mantle. We describe pockets of melt trapped in aggregates of corundum crystals ejected from Cretaceous volcanoes in northern Israel which contain high-temperature mineral assemblages requiring extremely low fO2 (IW < -10). One abundant phase is tistarite (Ti2O3), previously known as a single grain in the Allende carbonaceous chondrite (Mexico) and believed to have formed during the early evolution of the solar nebula. It is associated with other reduced phases usually found in meteorites. The development of super-reducing conditions in Earth's upper mantle may reflect the introduction of CH4 + H2 fluids from the deep mantle, specifically related to deep-seated volcanic plumbing systems at plate boundaries.
DS201710-2280
2017
Gain, S.E.M.Xiong, Q., Griffin, W.L., Huang, J-X., Gain, S.E.M., Toledo, V., Pearson, N.J., O'Reilly, S.Y.Super reduced assemblages in "ophiolitic" chromitites and peridotites: the view from Mount Carmel.European Journal of Mineralogy, Vol. 29, 4, pp. 557-570.Europe, Israelmineralogy

Abstract: Ultrahigh-pressure (UHP) materials (e.g., diamond, high-pressure polymorph of chromite) and super-reduced (SuR) phases (e.g., carbides, nitrides, silicides and native metals) have been identified in chromitites and peridotites of the Tibetan and Polar-Urals ophiolites. These unusual assemblages suggest previously unrecognized fluid- or melt-related processes in the Earth’s mantle. However, the origin of the SuR phases, and in particular their relationships with the UHP materials in the ophiolites, are still enigmatic. Studies of a recently recognized SuR mineral system from Cretaceous volcanics on Mt Carmel, Israel, suggest an alternative genesis for the ophiolitic SuR phases. The Mt Carmel SuR mineral system (associated with Ti-rich corundum xenocrysts) appears to reflect the local interaction of mantle-derived CH4 ± H2 fluids with basaltic magmas in the shallow lithosphere (depths of ?30-100 km). These interactions produced desilication of the magma, supersaturation in Al2O3 leading to rapid growth of corundum, and phase assemblages requiring local oxygen fugacity (fO2) gradually dropping to ?11 log units below the iron-wüstite (IW) buffer. The strong similarities between this system and the SuR phases and associated Ti-rich corundum in the Tibetan and Polar-Urals ophiolites suggest that the ophiolitic SuR suite probably formed by local influx of CH4 ± H2 fluids within previously subducted peridotites (and included chromitites) during their rapid exhumation from the deep upper mantle to lithospheric levels. In the final stages of their ascent, the recycled peridotites and chromitites were overprinted by a shallow magmatic system similar to that observed at Mt Carmel, producing most of the SuR phases and eventually preserving them within the Tibetan and Polar-Urals ophiolites.
DS201806-1225
2018
Gain, S.E.M.Griffin, W.L., Huang, J-X., Thomassot, E., Gain, S.E.M., Toledo, V., O'Reilley, S.Y.Super reducing conditions in ancient and modern volcanic systems: sources and behaviour of carbon-rich fluids in the lithospheric mantle. Mt. Carmel moissaniteMineralogy and Petrology, in press available, 14p.Europe, Israelmetasomatism

Abstract: Oxygen fugacity (fO2) is a key parameter of Earth’s mantle, because it controls the speciation of the fluids migrating at depth; a major question is whether the sublithospheric mantle is metal-saturated, keeping fO2 near the Iron-Wustite (IW) buffer reaction. Cretaceous basaltic pyroclastic rocks on Mt. Carmel, Israel erupted in an intraplate environment with a thin, hot lithosphere. They contain abundant aggregates of hopper-shaped crystals of Ti-rich corundum, which have trapped melts with phenocryst assemblages (Ti2O3, SiC, TiC, silicides, native V) requiring extremely low fO2. These assemblages are interpreted to reflect interaction between basaltic melts and mantle-derived fluids dominated by CH4 + H2. Similar highly reduced assemblages are found associated with volcanism in a range of tectonic situations including subduction zones, major continental collisions, intraplate settings, craton margins and the cratons sampled by kimberlites. This distribution, and the worldwide similarity of ?13C in mantle-derived SiC and associated diamonds, suggest a widespread process, involving similar sources and independent of tectonic setting. We suggest that the common factor is the ascent of abiotic (CH4 + H2) fluids from the sublithospheric mantle; this would imply that much of the mantle is metal-saturated, consistent with observations of metallic inclusions in sublithospheric diamonds (e.g. Smith et al. 2016). Such fluids, perhaps carried in rapidly ascending deep-seated magmas, could penetrate high up into a depleted cratonic root, establishing the observed trend of decreasing fO2 with depth (e.g. Yaxley et al. in Lithos 140:142-151, 2012). However, repeated metasomatism (associated with the intrusion of silicate melts) will raise the FeO content near the base of the craton over time, developing a carapace of oxidizing material that would prevent the rise of CH4-rich fluids into higher levels of the subcontinental lithospheric mantle (SCLM). Oxidation of these fluids would release CO2 and H2O to drive metasomatism and low-degree melting both in the carapace and higher in the SCLM. This model can explain the genesis of cratonic diamonds from both reduced and oxidized fluids, the existence of SiC as inclusions in diamonds, and the abundance of SiC in some kimberlites. It should encourage further study of the fine fractions of heavy-mineral concentrates from all types of explosive volcanism.
DS201808-1749
2018
Gain, S.E.M.Griffin, W.L., Huang, J-X., Thomassot, E., Gain, S.E.M., Toledo, V., O'Reilly, S.Y.Super-reducing conditions in ancient and modern volcanic systems: sources and behaviour of carbon-rich fluids in the lithospheric mantle ( Mt. Carmel).Mineralogy and Petrology, doi.org/10.1007/s00710-018-0575-x 14p.Mantlemoissanite
DS201810-2323
2018
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Huang, J.X., Belousova, E.A., Toledo, V., O'Reilly, S.Y.Permian to quaternary magmatism beneath the Mt. Carmel area, Israel: zircons from volcanic rocks and associated alluvial deposits.Lithos, Vol. 314-315, pp. 307-322.Europe, Israel zircons

Abstract: Xenocrystic zircons from Cretaceous pyroclastic vents on Mt. Carmel, N. Israel, document two major periods of earlier mafic magmatism: Permo-Triassic (285-220?Ma) and Jurassic (200-160?Ma). Related alluvial deposits also contain these zircon populations. However, most alluvial zircons are Cretaceous (118-80?Ma) or younger, derived from Miocene to Pliocene volcanic episodes. The Permo-Triassic-Jurassic zircons are typically large and glassy; they have irregular shapes and a wide variety of internal zoning patterns. They appear to have grown in the interstitial spaces of coarse-grained rocks; many show evidence of recrystallization, including brecciation and rehealing by chemically similar zircon. Grains with relict igneous zoning have mantle-like ?18O (5.5?±?1.0‰), but brecciation leads to lower values (mean 4.8‰, down to 3.1‰). Hf-isotope compositions lie midway between the Chondritic Uniform Reservoir (CHUR) and Depleted Mantle (DM) reservoirs; Hf model ages suggest that the source region separated from DM in Neoproterozoic time (1500-1000?Ma). Most Cretaceous zircons have 176Hf/177Hf similar to those of the older zircons, suggesting recrystallization and/or Pb loss from older zircons in the Cretaceous thermal event. The Permo-Jurassic zircons show trace-element characteristics similar to those crystallized from plume-related magmas (Iceland, Hawaii). Calculated melts in equilibrium with them are characterized by strong depletion in LREE and P, large positive Ce anomalies, variable Ti anomalies, and high and variable Nb, Ta, Th and U, consistent with the fractionation of monazite, zircon, apatite and Ti-bearing phases. We suggest that these coarse-grained zircons crystallized from late differentiates of mafic magmas, ponded near the crust-mantle boundary (ca 30?km depth), and were reworked repeatedly by successively younger igneous/metasomatic fluids. The zircon data support a published model that locates a fossil Neoproterozoic plume head beneath much of the Arabia-Levant region, which has been intermittently melted to generate the volcanic rocks of the region. The Cretaceous magmas carry mantle xenoliths derived from depths up to 90?km, providing a minimum depth for the possible plume head. Post-Cretaceous magmatism, as recorded in detrital zircons, shows distinct peaks at 30?Ma, 13?Ma, 11.4?±?0.1?Ma (a major peak; n?=?15), 9-10?Ma and 4?Ma, representing the Lower and Cover Basalts in the area. Some of these younger magmas tapped the same mantle source as the Permian-Jurassic magmatism, but many young zircons have Hf-isotope compositions extending up to DM values, suggesting derivation of magmas from deeper, more juvenile sources.
DS201810-2360
2018
Gain, S.E.M.Nasdala, L., Corfu, F., Schoene, B., Tapster, S.R., Wall, C.J., Schmitz, M.D., Ovtcharova, M., Schaltegger, U., Kennedy, A.K., Kronz, A., Reiners, P.W., Yang, Y-H., Wu, F-Y., Gain, S.E.M., Griffin, W.L., Szymanowski, D., Chanmuang, C., Ende, N.M., ValleyGZ7 and GZ8 - two zircon reference materials for SIMS U-Pb geochronology.Geostandards and Geoanalytical Research, http://orchid.org/0000-0002-2701-4635 80p.Asia, Sri Lankageochronology

Abstract: Here we document a detailed characterization of two zircon gemstones, GZ7 and GZ8. Both stones had the same mass at 19.2 carats (3.84 g) each; both came from placer deposits in the Ratnapura district, Sri Lanka. The U-Pb data are in both cases concordant within the uncertainties of decay constants and yield weighted mean ²??Pb/²³?U ages (95% confidence uncertainty) of 530.26 Ma ± 0.05 Ma (GZ7) and 543.92 Ma ± 0.06 Ma (GZ8). Neither GZ7 nor GZ8 have been subjected to any gem enhancement by heating. Structure?related parameters correspond well with the calculated alpha doses of 1.48 × 10¹? g?¹ (GZ7) and 2.53 × 10¹? g?¹ (GZ8), respectively, and the (U-Th)/He ages of 438 Ma ± 3 Ma (2s) for GZ7 and 426 Ma ± 9 Ma (2s) for GZ8 are typical of unheated zircon from Sri Lanka. The mean U concentrations are 680 ?g g?¹ (GZ7) and 1305 ?g g?¹ (GZ8). The two zircon samples are proposed as reference materials for SIMS (secondary ion mass spectrometry) U-Pb geochronology. In addition, GZ7 (Ti concentration 25.08 ?g g?¹ ± 0.18 ?g g?¹; 95% confidence uncertainty) may prove useful as reference material for Ti?in?zircon temperature estimates.
DS201902-0275
2018
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Bindi, L., Toledo, V., Camara, F., Saunders, M., O'Reilly, S.Y.Carmeltazite, ZrAl2Ti4011, a new mineral trapped in corundum from volcanic rocks of Mt Carmel, northern Israel.Minerals ( mdpi.com), Vol. 8, 12, 11p. PdfEurope, Israelmineralogy

Abstract: The new mineral species carmeltazite, ideally ZrAl2Ti4O11, was discovered in pockets of trapped melt interstitial to, or included in, corundum xenocrysts from the Cretaceous Mt Carmel volcanics of northern Israel, associated with corundum, tistarite, anorthite, osbornite, an unnamed REE (Rare Earth Element) phase, in a Ca-Mg-Al-Si-O glass. In reflected light, carmeltazite is weakly to moderately bireflectant and weakly pleochroic from dark brown to dark green. Internal reflections are absent. Under crossed polars, the mineral is anisotropic, without characteristic rotation tints. Reflectance values for the four COM wavelengths (Rmin, Rmax (%) (? in nm)) are: 21.8, 22.9 (471.1); 21.0, 21.6 (548.3), 19.9, 20.7 (586.6); and 18.5, 19.8 (652.3). Electron microprobe analysis (average of eight spot analyses) gave, on the basis of 11 oxygen atoms per formula unit and assuming all Ti and Sc as trivalent, the chemical formula (Ti3+3.60Al1.89Zr1.04Mg0.24Si0.13Sc0.06Ca0.05Y0.02Hf0.01)?=7.04O11. The simplified formula is ZrAl2Ti4O11, which requires ZrO2 24.03, Al2O3 19.88, and Ti2O3 56.09, totaling 100.00 wt %. The main diffraction lines, corresponding to multiple hkl indices, are (d in Å (relative visual intensity)): 5.04 (65), 4.09 (60), 2.961 (100), 2.885 (40), and 2.047 (60). The crystal structure study revealed carmeltazite to be orthorhombic, space group Pnma, with unit-cell parameters a = 14.0951 (9), b = 5.8123 (4), c = 10.0848 (7) Å, V = 826.2 (1) Å3, and Z = 4. The crystal structure was refined to a final R1 = 0.0216 for 1165 observed reflections with Fo > 4?(Fo). Carmeltazite exhibits a structural arrangement similar to that observed in a defective spinel structure. The name carmeltazite derives from Mt Carmel (“CARMEL”) and from the dominant metals present in the mineral, i.e., Titanium, Aluminum and Zirconium (“TAZ”). The mineral and its name have been approved by the IMA Commission on New Minerals, Nomenclature and Classification (2018-103).
DS201903-0514
2019
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Huang, J-X., Saunders, M., Shaw, J., Toledo, V., O'Reilly, S.Y.A terrestrial magmatic hibonite-grossite-vanadium assemblage: desilication and extreme reduction in a volcanic plumbing system, Mount Carmel, Israel.American Mineralogist, Vol. 104, pp. 207-219.Europe, Israelmelting

Abstract: Hibonite (CaAl12O19) is a constituent of some refractory calcium-aluminum inclusions (CAIs) in carbonaceous meteorites, commonly accompanied by grossite (CaAl4O7) and spinel. These phases are usually interpreted as having condensed, or crystallized from silicate melts, early in the evolution of the solar nebula. Both Ca-Al oxides are commonly found on Earth, but as products of high-temperature metamorphism of pelitic carbonate rocks. We report here a unique occurrence of magmatic hibonitegrossite-spinel assemblages, crystallized from Ca-Al-rich silicate melts under conditions [high-temperature, very low oxygen fugacity (fO2)] comparable to those of their meteoritic counterparts. Ejecta from Cretaceous pyroclastic deposits on Mt Carmel, N. Israel, include aggregates of hopper/skeletal Ti-rich corundum, which have trapped melts that crystallized at fO2 extending from 7 log units below the iron-wustite buffer (?IW = -7; SiC, Ti2O3, Fe-Ti silicide melts) to ?IW ? -9 (native V, TiC, and TiN). The assemblage hibonite + grossite + spinel + TiN first crystallized late in the evolution of the melt pockets; this hibonite contains percentage levels of Zr, Ti, and REE that reflect the concentration of incompatible elements in the residual melts as corundum continued to crystallize. A still later stage appears to be represented by coarse-grained (centimeter-size crystals) ejecta that show the crystallization sequence: corundum + Liq ? (low-REE) hibonite ? grossite + spinel ± krotite ? Ca4Al6F2O12 + fluorite. V0 appears as spheroidal droplets, with balls up to millimeter size and spectacular dendritic intergrowths, included in hibonite, grossite, and spinel. Texturally late V0 averages 12 wt% Al and 2 wt% Mn. Spinels contain 10-16 wt% V in V0-free samples, and <0.5 wt% V in samples with abundant V 0. Ongoing paragenetic studies suggest that the fO2 evolution of the Mt Carmel magmatic system reflects the interaction between OIB-type mafic magmas and mantle-derived CH4+H2 fluids near the crust-mantle boundary. Temperatures estimated by comparison with 1 atm phase-equilibrium studies range from ca. 1500 °C down to 1200-1150 °C. When fO2 reached ca. ?IW = -7, the immiscible segregation of Fe,Ti-silicide melts and the crystallization of SiC and TiC effectively desilicated the magma, leading to supersaturation in Al2O3 and the rapid crystallization of corundum, preceding the development of the hibonite-bearing assemblages. Reports of Ti-rich corundum and SiC from other areas of explosive volcanism suggest that these phenomena may be more widespread than presently realized, and the hibonite-grossite assemblage may serve as another indicator to track such activity. This is the first reported terrestrial occurrence of krotite (CaAl2O4), and of at least two unknown Zr-Ti oxides.
DS201906-1276
2019
Gain, S.E.M.Bindi, L., Camara, F., Griffin, W.L., Huang, J-X., Gain, S.E.M., Toledo, V., O'Reilly, S.Y.Discovery of the first natural hydride. Mt. CarmelAmerican Mineralogist, Vol. 104, pp. 611-614.Europe, Israelcrystallography

Abstract: Although hydrogen is the most abundant element in the solar system, the mechanisms of exchange of this element between the deep interior and surface of Earth are still uncertain. Hydrogen has profound effects on properties and processes on microscopic-to-global scales. Here we report the discovery of the first hydride (VH2) ever reported in nature. This phase has been found in the ejecta of Cretaceous pyroclastic volcanoes on Mt Carmel, N. Israel, which include abundant xenoliths containing highly reduced mineral assemblages. These xenoliths were sampled by their host magmas at different stages of their evolution but are not genetically related to them. The xenoliths are interpreted as the products of extended interaction between originally mafic magmas and CH4+H2 fluids, derived from a deeper, metal-saturated mantle. The last stages of melt evolution are recorded by coarse-grained aggregates of hibonite (CaAl12O19) + grossite (CaAl4O7) + V-rich spinels ± spheroidal to dendritic inclusions of metallic vanadium (V0), apparently trapped as immiscible metallic melts. The presence of V0 implies low oxygen fugacities and suggests crystallization of the aggregates in a hydrogen-rich atmosphere. The presence of such reducing conditions in the upper mantle has major implications for the transport of carbon, hydrogen and other volatile species from the deep mantle to the surface.
DS201906-1293
2019
Gain, S.E.M.Gain, S.E.M., Greau, Y., Henry, H., Belousova, E., Dainis, I., Griffin, W.L., O'Reilly, S.Y.Mud Tank zircon: long term evaluation of a reference material for U-Pb dating, Hf-isotope analysis and trace element analysis. ( Carbonatite)Geostandards and Geoanalytical Research, in press available, 16p.Australiadeposit - Mud Tank

Abstract: Zircon megacrysts from the Mud Tank carbonatite, Australia, are being used in many laboratories as a reference material for LA?ICP?MS U?Pb dating and trace element measurement, and LA?MC?ICP?MS determination of Hf isotopes. We summarise a database of > 10000 analyses of Mud Tank zircon (MTZ), collected from 2000 to 2018 during its use as a secondary reference material for simultaneous U?Pb and trace element analysis, and for Hf?isotope analysis. Trace element mass fractions are highest in dark red?brown stones and lowest in colourless and gem?quality ones. Individual unzoned grains can be chemically homogeneous, while significant variations in trace element mass fraction are associated with oscillatory zoning. Chondrite?normalised trace element patterns are essentially parallel over large mass fraction ranges. A Concordia age of 731.0 ± 0.2 Ma (2s, n = 2272) is taken as the age of crystallisation. Some grains show lower concordant to mildly discordant ages, probably reflecting minor Pb loss associated with cooling and the Alice Springs Orogeny (450-300 Ma). Our weighted mean 176Hf/177Hf is 0.282523 ± 10 (2s, n = 9350); the uncertainties on this ratio reflect some heterogeneity, mainly between grains. A few analyses suggest that colourless grains have generally lower 176Hf/177Hf. MTZ is a useful secondary reference material for U?Pb and Hf?isotope analysis, but individual grains need to be carefully selected using CL imaging and tested for homogeneity, and ideally should be standardised by solution analysis.
DS202012-2217
2020
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Saunders, M., Bindi, L., Alard, O., Toledo, V., O'Reilly, S.Y.Parageneses of TiB2 in corundum xenoliths from Mt. Carmel, Israel: siderophile behavior of boron under reducing conditions.American Mineralogist, Vol. 105, pp. 1609-1621. pdfEurope, Israeldeposit - Mt. Carmel

Abstract: Titanium diboride (TiB2) is a minor but common phase in melt pockets trapped in the corundum aggregates that occur as xenoliths in Cretaceous basaltic volcanoes on Mt. Carmel, north Israel. These melt pockets show extensive textural evidence of immiscibility between metallic (Fe-Ti-C-Si) melts, Ca-Al-Mg-Si-O melts, and Ti-(oxy)nitride melts. The metallic melts commonly form spherules in the coexisting oxide glass. Most of the observed TiB2 crystallized from the Fe-Ti-C silicide melts and a smaller proportion from the oxide melts. The parageneses in the melt pockets of the xenoliths require fO2 ? ?IW-6, probably generated through interaction between evolved silicate melts and mantle-derived CH4+H2 fluids near the crust-mantle boundary. Under these highly reducing conditions boron, like carbon and nitrogen, behaved mainly as a siderophile element during the separation of immiscible metallic and oxide melts. These parageneses have implications for the residence of boron in the peridotitic mantle and for the occurrence of TiB2 in other less well-constrained environments such as ophiolitic chromitites.
DS202101-0001
2020
Gain, S.E.M.Bindi, L., Camara, F., Gain, S.E.M., Griffin, W.L., Huang, J-X., Saunders, M., Toledo, V.Kishonite, VH2 and oreillyite, Cr2N, two new minerals from the conundrum xenocrysts of Mt. Carmel, northern Israel.Minerals MDPI, Vol. 10, 1118, doi:10.3390/ min10121118 10p. PdfEurope, Israeldeposit - Mt. Carmel

Abstract: Here, we describe two new minerals, kishonite (VH2) and oreillyite (Cr2N), found in xenoliths occurring in pyroclastic ejecta of small Cretaceous basaltic volcanoes exposed on Mount Carmel, Northern Israel. Kishonite was studied by single-crystal X-ray diffraction and was found to be cubic, space group Fm3¯m, with a = 4.2680(10) Å, V = 77.75(3) Å3, and Z = 4. Oreillyite was studied by both single-crystal X-ray diffraction and transmission electron microscopy and was found to be trigonal, space group P3¯1m, with a = 4.7853(5) Å, c = 4.4630(6) Å, V = 88.51 Å3, and Z = 3. The presence of such a mineralization in these xenoliths supports the idea of the presence of reduced fluids in the sublithospheric mantle influencing the transport of volatile species (e.g., C, H) from the deep Earth to the surface. The minerals and their names have been approved by the Commission of New Minerals, Nomenclature and Classification of the International Mineralogical Association (No. 2020-023 and 2020-030a).
DS202101-0013
2020
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Saunders, M., Bindi, L., Alard, O., Toledo, V., O'Reilly, S.Y.Parageneses of TIB2 in corundum xenoliths from Mt. Carmel, Israel: siderophile behaviour of boron under reducing conditions.American Mineralogist , in press available 33p. PdfEurope, Israeldeposit - Mt. Carmel

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

Abstract: Titanium oxynitrides (Ti(N,O,C)) are abundant in xenolithic corundum aggregates in pyroclastic ejecta of Cretaceous volcanoes on Mount Carmel, northern Israel. Petrographic observations indicate that most of these nitrides existed as melts, immiscible with coexisting silicate and Fe-Ti-C silicide melts; some nitrides may also have crystallized directly from the silicide melts. The TiN phase shows a wide range of solid solution, taking up 0-10 wt% carbon and 1.7-17 wt% oxygen; these have crystallized in the halite (fcc) structure common to synthetic and natural TiN. Nitrides coexisting with silicide melts have higher C/O than those coexisting with silicate melts. Analyses with no carbon fall along the TiN-TiO join in the Ti-N-O phase space, implying that their Ti is a mixture of Ti3+ and Ti2+, while those with 1-3 at.% C appear to be solid solutions between TiN and Ti0.75O. Analyses with >10 at% C have higher Ti2+/Ti3+, reflecting a decrease in fO2. Oxygen fugacity was 6 to 8 log units below the iron-wüstite buffer, at or below the Ti2O3-TiO buffer. These relationships and coexisting silicide phases indicate temperatures of 1400-1100 °C. Ti oxynitrides are probably locally abundant in the upper mantle, especially in the presence of CH4-H2 fluids derived from the deeper metal-saturated mantle.
DS202110-1616
2021
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Saunders, M., Camara, F., Bindi, L., Sparta, D., Toledo, V., O'Reilly, S.Y.Cr203 in corundum: ultrahigh contents under reducing conditions. American Mineralogist, Vol. 106, pp. 1420-1437. pdfEurope, Israeldeposit - Mount Carmel

Abstract: Xenocrysts and xenoliths in Upper Cretaceous pyroclastics on Mount Carmel (northern Israel) represent a series of similar magma-fluid systems at different stages of their evolution, recording a continuous decrease in oxygen fugacity (fO2) as crystallization proceeded. Corundum coexisting with Fe-Mg-Cr-Al spinels, other Fe-Mg-Al-Na oxides, and Fe-Ni alloys in apparent cumulates crystallized at fO2 values near the iron-wüstite (IW) buffer (fO2 = IW±1) and is zoned from high-Cr cores to lower-Cr rims, consistent with fractional crystallization trends. The reconstructed parental melts of the cumulates are Al-Cr-Fe-Mg oxides with ca. 2 wt% SiO2. Corundum in other possible cumulates that contain Cr-Fe (Fe 45 wt%) alloys has low-Cr cores and still lower-Cr rims. Corundum coexisting with Cr0 (fO2 = IW-5) in some possible cumulates has low-Cr cores, but high-Cr rims (to >30% Cr2O3). These changes in zoning patterns reflect the strong decrease in the melting point of Cr2O3, relative to Al2O3, with decreasing fO2. The electron energy loss spectroscopy (EELS) analyses show that all Cr in corundum that coexists with Cr0 is present as Cr3+. This suggests that late in the evolution of these reduced melts, Cr2+ has disproportionated via the reaction 3Cr2+(melt) ? 2Cr3+(Crn) + Cr0. The most Cr-rich corundum crystallized together with ?-alumina phases including NaAl11O17 (diaoyudaoite) and KAl11O17 (kahlenbergite) and ??-alumina phases; residual melts crystallized a range of (K,Mg)2(Al,Cr)10O17 phases with the kahlenbergite structure. The parental melts of these assemblages appear to have been Al-Cr-K-Na-Mg oxides, which may be related to the Al-Cr-Fe-Mg oxide melts mentioned above, through fractional crystallization or liquid immiscibility. These samples are less reduced (fO2 from IW to IW-5) than the assemblages of the trapped silicate melts in the more abundant xenoliths of corundum aggregates (fO2 = IW-6 to IW-10). They could be considered to represent an earlier stage in the fO2 evolution of an “ideal” Mt. Carmel magmatic system, in which mafic or syenitic magmas were fluxed by mantle-derived CH4+H2 fluids. This is a newly recognized step in the evolution of the Mt. Carmel assemblages and helps to understand element partitioning under highly reducing conditions.
DS202204-0520
2022
Gain, S.E.M.Griffin, W.L., Gain, S.E.M., Saunders, M.J., Huang, J-X., Alard, O., Toledo, V., O'Reilly, S.Y.Immiscible metallic melts in the upper mantle beneath Mount Carmel, Israel: silicides, phosphides, and carbides.American Mineralogist, Vol. 107, pp. 532-549.Europe, Israeldeposit - Mount Carmel

Abstract: Xenolithic corundum aggregates in Cretaceous mafic pyroclastics from Mount Carmel contain pockets of silicate melts with mineral assemblages [SiC (moissanite), TiC, Ti2O3 (tistarite), Fe-Ti-Zr silicides/phosphides] indicative of magmatic temperatures and oxygen fugacity (fO2) at least 6 log units below the iron-wüstite buffer (?IW ? -6). Microstructural evidence indicates that immiscible, carbon-rich metallic (Fe-Ti-Zr-Si-P) melts separated during the crystallization of the silicate melts. The further evolution of these metallic melts was driven by the crystallization of two main ternary phases (FeTiSi and FeTiSi2) and several near-binary phases, as well as the separation of more evolved immiscible melts. Reconstructed melt compositions fall close to cotectic curves in the Fe-Ti-Si system, consistent with trapping as metallic liquids. Temperatures estimated from comparisons with experimental work range from ?1500 °C to ca. 1150 °C; these probably are maximum values due to the solution of C, H, P, and Zr. With decreasing temperature (T), the Si, Fe, and P contents of the Fe-Ti-Si melts increased, while contents of Ti and C decreased. The increase in Si with declining T implies a corresponding decrease in fO2, probably to ca. ?IW-9. The solubility of P in the metallic melts declined with T and fO2, leading to immiscibility between Fe-Ti-Si melts and (Ti,Zr)-(P,Si) melts. Decreasing T and fO2 also reduced the solubility of C in the liquid metal, driving the continuous crystallization of TiC and SiC during cooling. The lower-T metallic melts are richer in Cr, and to some extent V, as predicted by experimental studies showing that Cr and V become more siderophile with decreasing fO2. These observations emphasize the importance of melt-melt immiscibility for the evolution of magmas under reducing conditions. The low fO2 and the abundance of carbon in the Mt. Carmel system are consistent with a model in which differentiating melts were fluxed by fluids that were dominated by CH4+H2, probably derived from a metal-saturated sublithospheric mantle. A compilation of other occur-rences suggests that these phenomena may commonly accompany several types of explosive volcanism.
DS2001-0813
2001
Gaina, C.Muller, R.D., Gaina, C., Roest, W.R., KLunbek HansenA recipe for microcontinent formationGeology, Vol. 29, No. 3, Mar. pp.203-6.GreenlandPlumes, accretion, terranes, Tectonics
DS200412-0601
2004
Gaina, C.Gaina, C., Muller, R.D., Brown, B.J., Ishihara, T.Microcontinent formation around Australia.Hillis, R.R., Muller, R.D. Evolution and dynamics of the Australian Plate, Geological Society America Memoir, No. 372, pp. 405-416.AustraliaTectonics
DS200412-1378
2004
Gaina, C.Muller, R.D., Gaina, C.Tectonic evolution of the southwest Pacific using constraints from backarc basins.Hillis, R.R., Muller, R.D. Evolution and dynamics of the Australian Plate, Geological Society America Memoir, No. 372, pp. 343-360.AustraliaTectonics
DS200412-1379
2004
Gaina, C.Muller, R.D., Gaina, C., Struckmeyer, H.I.M., Stagg, H.M.J., Symonds, P.A.Formation and evolution of Australian passive margins: implications for locating the boundary between continental and oceanic crHillis, R.R., Muller, R.D. Evolution and dynamics of the Australian Plate, Geological Society America Memoir, No. 372, pp. 223-244.AustraliaTectonics
DS200812-0024
2008
Gaina, C.Alvey, A., Gaina, C.,Kusznir, N.J., Torsvik, T.H.Integrated crustal thickness mapping and plate reconstructions for the high Arctic.Earth and Planetary Science Letters, In press availableCanada, Arctic, GreenlandTectonics, plate, lithosphere
DS201012-0793
2010
Gaina, C.Torsvik, T.H., Steinberger, B., Gurnis, M., Gaina, C.Plate tectonics and net lithosphere rotation over the past 150 My.Earth and Planetary Science Letters, Vol. 291, 1-4, pp. 106-112.MantleTectonics
DS201112-1074
2011
Gaina, C.Van Hinsbergen, D.J.J., Buiter, S.J.H., Torsvik, T.H., Gaina, C., Webb, S.J.The formation and evolution of Africa from the Archean to Present; introduction.The Formation and Evolution of Africa: A synopsis of 3.8 Ga of Earth History, Geol. Soc. London Special Publ., 357, pp. 1-8.AfricaHistory
DS201606-1116
2016
Gaina, C.Shephard, G.E., Tronnes, R.G., Spakman, W., Panet, I., Gaina, C.Evidence of slab material under Greenland and links to Cretaceous high Arctic magmatism.Geophysical Research Letters, Vol. 43, 8, pp. 3717-3726.Europe, GreenlandMagmatism

Abstract: Understanding the evolution of extinct ocean basins through time and space demands the integration of surface kinematics and mantle dynamics. We explore the existence, origin, and implications of a proposed oceanic slab burial ground under Greenland through a comparison of seismic tomography, slab sinking rates, regional plate reconstructions, and satellite-derived gravity gradients. Our preferred interpretation stipulates that anomalous, fast seismic velocities at 1000-1600?km depth imaged in independent global tomographic models, coupled with gravity gradient perturbations, represent paleo-Arctic oceanic slabs that subducted in the Mesozoic. We suggest a novel connection between slab-related arc mantle and geochemical signatures in some of the tholeiitic and mildly alkaline magmas of the Cretaceous High Arctic Large Igneous Province in the Sverdrup Basin. However, continental crustal contributions are noted in these evolved basaltic rocks. The integration of independent, yet complementary, data sets provides insight into present-day mantle structure, magmatic events, and relict oceans.
DS201607-1315
2016
Gaina, C.Shephard, G.E., Tronnes, R.G., Sparkman< W., Panet, I., Gaina, C.Evidence for slab material under Greenland and links to Cretaceous High Arctic magmatism.Geophysical Research Letters, Vol. 43, 8, pp. 3717-3726.Europe, GreenlandMagmatism

Abstract: Understanding the evolution of extinct ocean basins through time and space demands the integration of surface kinematics and mantle dynamics. We explore the existence, origin, and implications of a proposed oceanic slab burial ground under Greenland through a comparison of seismic tomography, slab sinking rates, regional plate reconstructions, and satellite-derived gravity gradients. Our preferred interpretation stipulates that anomalous, fast seismic velocities at 1000 -1600?km depth imaged in independent global tomographic models, coupled with gravity gradient perturbations, represent paleo-Arctic oceanic slabs that subducted in the Mesozoic. We suggest a novel connection between slab-related arc mantle and geochemical signatures in some of the tholeiitic and mildly alkaline magmas of the Cretaceous High Arctic Large Igneous Province in the Sverdrup Basin. However, continental crustal contributions are noted in these evolved basaltic rocks. The integration of independent, yet complementary, data sets provides insight into present-day mantle structure, magmatic events, and relict oceans.
DS201612-2337
2016
Gaina, C.Shephard, G.E., Tronnes, R.G., Spakman, W., Panet, I., Gaina, C.Evidence for slab material under Greenland and links to Cretaceous high arctic magmatism.Geophysical Research Letters, Vol. 7, 10.1002/ 2016GL068424Europe, GreenlandMagmatism

Abstract: Understanding the evolution of extinct ocean basins through time and space demands the integration of surface kinematics and mantle dynamics. We explore the existence, origin, and implications of a proposed oceanic slab burial ground under Greenland through a comparison of seismic tomography, slab sinking rates, regional plate reconstructions, and satellite-derived gravity gradients. Our preferred interpretation stipulates that anomalous, fast seismic velocities at 1000-1600?km depth imaged in independent global tomographic models, coupled with gravity gradient perturbations, represent paleo-Arctic oceanic slabs that subducted in the Mesozoic. We suggest a novel connection between slab-related arc mantle and geochemical signatures in some of the tholeiitic and mildly alkaline magmas of the Cretaceous High Arctic Large Igneous Province in the Sverdrup Basin. However, continental crustal contributions are noted in these evolved basaltic rocks. The integration of independent, yet complementary, data sets provides insight into present-day mantle structure, magmatic events, and relict oceans.
DS201904-0737
2019
Gaina, C.Gaina, C., Niocaill, C.M., Conrad, C.P., Steinberger, B., Svensen, H.H.Linking plate tectonics and volcanism to deep Earth dynamics - a tribute to Torsvik.Tectonophysics, in press available 6p.Mantlegeodynamics
DS201909-2056
2019
Gaina, C.Lebedeva-Ivanova, N., Gaina, C., Minakov, A., Kashubin, S.ArcCRUST: Arctic crustal thickness from 3-D gravity inversion.Geochemistry, Geophysics, Geosystems, Vol. 20 doi.org/10.1029 /2018GC008098Globalgeophysics - gravity

Abstract: An excess or deficit of mass is reflected in the gravity anomaly data. Gravity anomalies measured by satellite and airborne and shipborne instruments show variations in topography and bathymetry, sedimentary thickness, basement rock density contrast, crustal thickness, and even mantle convection. Using new geophysical data and an improved 3?D gravity inversion method, we calculate the crustal thickness of oceanic domains in the High Arctic and northern North Atlantic. This model helps to better understand the tectonic structure of poorly surveyed and difficult to access Arctic regions. ArcCRUST can be used to better constrain the deeper Arctic region structure.
DS202008-1453
2020
Gaina, C.van den Broeck, J.M., Gaina, C.Microcontinents and continental fragments associated with subduction systems.Tectonics, in press available, e2020TC006063 39p. PdfGlobalsubduction

Abstract: Microcontinents and continental fragments are small pieces of continental crust that are surrounded by oceanic lithosphere. Although classically associated with passive margin formation, here we present several preserved microcontinents and continental fragments associated with subduction systems. They are located in the Coral Sea, South China Sea, central Mediterranean and Scotia Sea regions and a ‘proto?microcontinent’, in the Gulf of California. Reviewing the tectonic history of each region and interpreting a variety of geophysical data allows us to identify parameters controlling the formation of microcontinents and continental fragments in subduction settings. All these tectonic blocks experienced long, complex tectonic histories with an important role for developing inherited structures. They tend to form in back?arc locations and separate from their parent continent by oblique or rotational kinematics. The separated continental pieces and associated marginal basins are generally small and formation is quick (<50 Myr). Microcontinents and continental fragments formed close to large continental masses tend to form faster than those created in systems bordered by large oceanic plates. A common triggering mechanism for formation is difficult to identify, but seems to be linked with rapid changes of complex subduction dynamics. The young ages of all contemporary pieces found in situ suggest that microcontinents and continental fragments in these settings are short lived. Although presently the amount of in?situ subduction?related microcontinents is meagre (an area of 0.56% and 0.28% of global, non?cratonic, continental crustal area and crustal volume respectively), through time microcontinents contributed to terrane amalgamation and larger continent formation.
DS202009-1672
2020
Gaina, C.van den Broek, J.M., Gaina, C.Microcontinents and continental fragments associated with subduction systems.Tectonics, 10.1029/2020/TC006063 29p. PdfGlobalsubduction

Abstract: Microcontinents and continental fragments are small pieces of continental crust that are surrounded by oceanic lithosphere. Although classically associated with passive margin formation, here we present several preserved microcontinents and continental fragments associated with subduction systems. They are located in the Coral Sea, South China Sea, central Mediterranean and Scotia Sea regions, and a “proto?microcontinent,” in the Gulf of California. Reviewing the tectonic history of each region and interpreting a variety of geophysical data allows us to identify parameters controlling the formation of microcontinents and continental fragments in subduction settings. All these tectonic blocks experienced long, complex tectonic histories with an important role for developing inherited structures. They tend to form in back?arc locations and separate from their parent continent by oblique or rotational kinematics. The separated continental pieces and associated marginal basins are generally small and their formation is quick (<50 Myr). Microcontinents and continental fragments formed close to large continental masses tend to form faster than those created in systems bordered by large oceanic plates. A common triggering mechanism for their formation is difficult to identify, but seems to be linked with rapid changes of complex subduction dynamics. The young ages of all contemporary pieces found in situ suggest that microcontinents and continental fragments in these settings are short lived. Although presently the amount of in?situ subduction?related microcontinents is meager (an area of 0.56% and 0.28% of global, non?cratonic, continental crustal area and crustal volume, respectively), through time microcontinents contributed to terrane amalgamation and larger continent formation.
DS201312-0387
2011
Gaina, G.Hinsbergen, D.J.J., Buiter, S.J.H., Torsvik, T.H., Gaina, G., Webb, S.J.Formation and evolution of Africa: a synopsis of 3.8 Ga of Earth history.Geological Society of London, Special Publication no. 357, 378p. Approx 120 lbsAfricaTectonics
DS201708-1643
2017
Gainer, D.Gainer, D.The geology of the Faraday 3 kimberlite, NWT, Canada.11th. International Kimberlite Conference, PosterCanada, Northwest Territoriesdeposit - Faraday 3
DS1989-0359
1989
Gaines, P.R.Dismukes, J.P., Gaines, P.R., Witzke, H., Leta, D.P., Kear, B.H.Demineralization and microstructure of carbonadoMater. Sci. Eng. Proceedings 'A struct. mater. prop. microstruct. Proceedings', Vol. 105-106, Dec.3rd International Sci Conference Hard Mat.pp. 555-63GlobalCarbonado
DS202111-1780
2021
Gaines, R.R.Peters, S.E., Walton, C.R., Husson, J.M., Quinn, D.P., Shorttle, O., Keller, C.B., Gaines, R.R.Igneous rock area and age in continental crust.Geology, Vol. 49, pp. 1235-1239. pdfGlobalgeochronology

Abstract: Rock quantity and age are fundamental features of Earth's crust that pertain to many problems in geoscience. Here we combine new estimates of igneous rock area in continental crust from the Macrostrat database (https://macrostrat.org/) with a compilation of detrital zircon ages in order to investigate rock cycling and crustal growth. We find that there is little or no decrease in igneous rock area with increasing rock age. Instead, igneous rock area in North America exhibits four distinct Precambrian peaks, remains low through the Neoproterozoic, and then increases only modestly toward the recent. Peaks in Precambrian detrital zircon age frequency distributions align broadly with peaks in igneous rock area, regardless of grain depositional age. However, detrital zircon ages do underrepresent a Neoarchean peak in igneous rock area; young grains and ca. 1.1 Ga grains are also overrepresented relative to igneous area. Together, these results suggest that detrital zircon age distributions contain signatures of continental denudation and sedimentary cycling that are decoupled from the cycling of igneous source rocks. Models of continental crustal evolution that incorporate significant early increase in volume and increased sedimentation in the Phanerozoic are well supported by these data.
DS1997-0367
1997
Gaines, R.V.Gaines, R.V., Skinner, H.C., Foord, E.E., Mason, B.Dana's new mineralogy. Eigth editionJ. Wiley, approx. $ 300.00 United StatesGlobalBook - ad, Mineralogy
DS1940-0046
1942
Gainier, P.W.Gainier, P.W.Green FireNew York: Random House., 296P.GlobalKimberlite, Kimberley, Janlib, Emerald
DS201212-0651
2012
Gainutdinov, R.Shiryaev, A., Gainutdinov, R., Fedortchouk, Y.Deformation induced defects in diamonds: contribution of small angle X-ray scattering and atomic force microscopy.emc2012 @ uni-frankfurt.de, 1p. AbstractTechnologyDiamond microscopy
DS201312-0289
2013
Gainutdinov, R.V.Gainutdinov, R.V., Shiryaev, A.A., Boyko, V.S., Fedortchouk, Y.Extended defects in natural diamonds: an atomic force microscopy investigation.Diamond and Related Materials, Vol. 40, pp. 17-23.TechnologyDiamond morphology
DS1950-0272
1956
Gair, J.E.Gair, J.E., Wier, K.L.Geology of the Kiernan Qaudrangle, Iron County, MichiganUnited States Geological Survey (USGS) Bulletin., No. 1044, 88P.United States, Michigan, Great LakesRegional Geology
DS200512-0250
2005
Gaister, A.V.Dudnikova, V.B., Gaister, A.V., Zharikov, E.V., Senin, V.G., Urusov, V.S.Chromium distribution between forsterite and its melt: dependence on chromium content in melt and redox conditions.Geochemistry International, Vol. 43, 5, pp. 471-477.MantleMelting
DS200712-0341
2007
Gait, A.D.Gait, A.D., Lowman, J.P.Time dependence in mantle convection models featuring dynamically evolving plates.Geophysical Journal International, Vol. 171, 1, October pp. 463-477.MantleConvection
DS200712-0342
2007
Gait, A.D.Gait, A.D., Lowman, J.P.Time dependence in mantle convection models featuring dynamically evolving plates.Geophysical Journal International, Vol. 171, 1, pp. 463-477.MantleConvection
DS200812-0377
2007
Gait, A.D.Gait, A.D., Lowman, J.P.Effect of lower mantle viscosity on the time dependence of plate velocities in three dimensional mantle convection models.Geophysical Research Letters, Vol. 34, 21, Nov. 16, ppp. L21304-07.MantleConvection
DS200812-0378
2008
Gait, A.D.Gait, A.D., Lowman, J.P., Gable, C.W.Time dependence in 3 D mantle convection models featuring evolving plates: effect of lower mantle viscosity.Journal of Geophysical Research, Vol. 113, B08409.MantleGeophysics - seismcis
DS200812-0379
2008
Gait, A.D.Gait, A.D., Lowman, J.P., Gable, C.W.Time dependence in 3 D mantle convection models featuring evolving plates: effect of lower mantle viscosity.Journal of Geophysical Research, Vol. 113, B8, B80409.MantleGeophysics - seismics
DS200912-0455
2008
Gait, A.D.Lowman, J.P., Gait, A.D., Gable, C.W., Kukreja, H.Plumes anchored by a high velocity lower mantle in a 3D mantle convection model featuring dynamically evolving plates.Geophysical Research Letters, Vol. 35, 19, Oct. 16, GLO35342MantleHotspots
DS2003-0506
2003
Gaitzsch, I.Grimmer, J.C., Ratschbacher, L., McWilliams, M., Franz, L., Gaitzsch, I., et al.When did the ultrahigh-pressure rocks reach the surface? A 207Pb 206 Pb zircon 40Chemical Geology, Vol. 197, 1-4, pp. 87-110.ChinaDabie Shan synorogenic foreland sediments, UHP
DS200412-0728
2003
Gaitzsch, I.Grimmer, J.C., Ratschbacher, L., McWilliams, M., Franz, L., Gaitzsch, I., et al.When did the ultrahigh-pressure rocks reach the surface? A 207Pb 206 Pb zircon 40 Ar 39Ar white mica, Si in white mica, single gChemical Geology, Vol. 197, 1-4, pp. 87-110.ChinaDabie Shan synorogenic foreland sediments UHP
DS200512-0068
2001
Gakhova, L.N.Baryshnikov, V.D., Gakhova, L.N., Kramskov, N.P.Stress state of the rock mass in the vicinity of underground mining workings, pit edges, and below its bottom.Journal of Mining Science, Vol. 37, 5, pp. 462-465.RussiaMining - Aikhal
DS200512-0069
2002
Gakhova, L.N.Baryshnikov, V.D., Gakhova, L.N., Kramskov, N.P.Stress state of ore mass in the ascending slice system.Journal of Mining Science, Vol. 38, 6, pp. 608-611.RussiaMining - International
DS200912-0036
2009
Gakhova, L.N.Baryshnikov, V.D., Gakhova, L.N.Geomechanical conditions of kimberlite extraction in terms of Internatsionalnaya kimberlite pipe,Journal of Mining Science, Vol. 45, 2, pp. 137-145.RussiaMining
DS1998-0460
1998
Gala, M.G.Gala, M.G., Symons, D.T.A., Palmer, H.C.Geotectonics of the Hanson Lake block, Trans-Hudson orogen: preliminary paleomagnetic report.Precambrian Research, Vol. 90, No. 1-2, June 30. pp. 85-?ManitobaTectonics, Orogeny
DS1988-0232
1988
Galakhov, A.V.Galakhov, A.V.Khibiny massif- a complex central type polychamber intrusive.(in Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 302, No. 3, pp. 673-675RussiaCarbonatite
DS1985-0548
1985
Galakhova, T.N.Pripachkin, V.A., Pavlova, M.A., Galakhova, T.N., et al.Bitumens of Khibini CarbonatitesDoklady Academy of Sciences Nauk SSSR., Vol. 281, No. 6, PP. 1424-1426.RussiaBlank
DS1986-0655
1986
Galakhova, T.N.Pripachkin, V.A., Pavlova, N.A., Galakhova, T.N., VolokhovaBitumens in carbonatites of the KhibinyDoklady Academy of Science USSR, Earth Science Section, Vol. 281, No. 1-6, November pp. 137-140RussiaCarbonatite
DS1960-1105
1969
Galanov, S.I.Galanov, S.I., et al.On Prospecting for Kimberlite Bodies in East SayanEastern Siberian Publishing House, Yakutsk., Russia, YakutiaKimberlite, Geophysics
DS201812-2786
2018
Galarneau, M.Bulbuc, K.M., Galarneau, M., Stachel, T., Stern, R.A., Kong, J., Chinn, I.Contrasting growth conditions for sulphide-and garnet-included diamonds from the Victor mine ( Ontario).2018 Yellowknife Geoscience Forum , p. 97-98. abstractCanada, Ontario, Attawapiskatdeposit - Victor

Abstract: The Victor Diamond Mine, located in the Attawapiskat kimberlite field (Superior Craton), is known for its exceptional diamond quality. Here we study the chemical environment of formation of Victor diamonds. We imaged eight sulphide-included diamond plates from Victor using cathodoluminescence (CL). Then, along core-rim transects, we measured nitrogen content and aggregation state utilizing Fourier Transform Infrared (FTIR) spectroscopy, and the stable isotope compositions of carbon (?13C) and nitrogen (?15N), using a multi-collector ion microprobe (MC-SIMS). We compare the internal growth features and chemical characteristics of these sulphide inclusion-bearing diamonds with similar data on garnet inclusion-bearing diamonds from Victor (BSc thesis Galarneau). Using this information, possible fractionation processes during diamond precipitation are considered and inferences on the speciation of the diamond forming fluid(s) are explored. Sulphide inclusion-bearing diamonds show much greater overall complexity in their internal growth features than garnet inclusion-bearing diamonds. Two of the sulphide-included samples have cores that represent an older generation of diamond growth. Compared to garnet inclusion-bearing diamonds, the sulphide-included diamonds show very little intra-sample variation in both carbon and nitrogen isotopic composition; the inter-sample variations in carbon isotopic composition, however, are higher than in garnet included diamonds. For sulphide-included diamonds, ?13C ranges from -3.4 to -17.5 and ?15N ranges from -0.2 to -9.2. Garnet inclusion-bearing diamonds showed ?13C values ranging from -4.6 to -6.0 and ?15N ranging from -2.8 to -10.8. The observation of some 13C depleted samples indicates that, unlike the lherzolitic garnet inclusion-bearing diamonds, the sulphide inclusion-bearing diamonds are likely both peridotitic and eclogitic in origin. The total range in N content across sulphide inclusion-bearing diamonds was 2 to 981 at ppm, similar to the garnet-included samples with a range of 5 to 944 at ppm. The very limited variations in carbon and nitrogen isotopic signatures across growth layers indicate that sulphide-included Victor diamonds grew at comparatively high fluid:rock ratios. This is contrasted by the garnet inclusion-bearing diamonds that commonly show the effects of Rayleigh fractionation and hence grew under fluid-limited conditions.
DS1990-0504
1990
Galasso, F.S.Galasso, F.S.Perovskites and high TC superconductorsGordon and Breach Publk, Book 293p. approx. $ 110.00 ISBN 2-88124-391-6GlobalPerovskites, Superconductors
DS202110-1633
2021
Galati, A.Persaud, S., Galati, A., Johnson, P.Colorful inclusions in diamond.Gems & Gemology, Vol. 57, 2, pp. 158-159. gia.edu/gems-gemologyUnited States, Californiadiamond inclusions
DS201112-0100
2011
Galbrun, B.Boulila, S., Galbrun, B., Miller, K.G., Pekar, S.F., Browning, J.V., Laskar, J., Wright, J.D.On the origin of Cenozoic and Mesozoic 'third order' eustatic sequences.Earth Science Reviews, Vol. 109, 3-4, pp. 94-112.GlobalGeomorphology - sea levels
DS201012-0800
2009
Galchenko, Y.P.Trubetskoy, K.N., Galchenko, Y.P., Ainbinder, L.L., Sabinyan, G.V.Outlook for the enhanced safety and improved efficiency of diamond deposit mining.Journal of Mining Science, Vol. 45, 6, pp. 581-590.RussiaMining - Yakutia pipes
DS2001-0351
2001
Galdeano, A.Galdeano, A., Asifirane, F., Nehlig, P.When was Arabia close to the pole?Earth and Planetary Science Letters, Vol. 193, No. 1-2, Nov. 30, pp. 25-37.ArabiaPaleomagnetism, Gondwanaland, Rodinia
DS200712-0767
2007
Galdeano, 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
DS1998-0797
1998
Galdin, N.E.Kouznetsova, E.I., Galdin, N.E.Continental lithosphere deep structure researches on the base of scientific deep drilling.7th International Kimberlite Conference Abstract, pp. 469-0.Russia, Kola PeninsulaMantle - lithosphere, Pechenga Structure, Baltic Shield
DS201412-0162
2014
Gale, A.Dalton, C.A., Langmuir, C.H., Gale, A.Report geophysical and geochemical evidence for deep temperature variations beneath mid-Ocean ridges.Science, Vol. 344, no. 6179, pp. 80-83.MantleGeophysics - seismics
DS1998-0653
1998
Gale, D.Indares, A., Dunning, G., Cox, R., Gale, D.high pressure high temperature rocks from the base of thick continentalcrust: Manicouagan imbricate zone.Tectonics, Vol. 17, No. 3, June pp. 426-40.Quebec, Labrador, Ungavametamorphism
DS1975-0598
1977
Gale, N.H.Paul, D.K., Gale, N.H., Harris, P.G.Uranium and Thorium Abundances in Indian KimberlitesGeochimica Et Cosmochimica Acta, Vol. 41, No. 2, PP. 335-339.IndiaIsotope
DS1980-0056
1980
Gale, N.H.Beckinsale, R.D., Gale, N.H., Parkhurst, R.J., Macfarlane, A.C.Discordant Rubidium-strontium and Lead Whole Rock Isochron Ages for ThePrecambrian Research., Vol. 13, No. 1, PP. 43-62.Sierra Leone, West AfricaGeochronology, Geology
DS1994-0321
1994
Galeotti, S.Coccioni, R., Galeotti, S.K-T boundary extinction: geologically instantaneous or gradual event?Evidence deep sea benthic formaniferaGeology, Vol. 22, No. 9, Sept. pp. 779-782GlobalK-T Boundary
DS1989-0459
1989
Galer, S.J.G.Galer, S.J.G., O'Nions, R.K.Chemical and isotopic studies of ultramafic inclusions from the San Carlos volcanic field, Arizona- a bearing on their petrogenesisJournal of Petrology, Vol. 30, No. 4, August pp. 1033-1064ArizonaGeochemistry, Geochronology, San Carlos
DS1991-0525
1991
Galer, S.J.G.Galer, S.J.G.Inter relationships between continental freeboard, tectonics and mantletemperatureEarth and Planetary Science Letters, Vol. 105, pp. 214-228GlobalSea-level, Archean tectonics
DS1992-1223
1992
Galer, S.J.G.Porcelli, D.R., O'Nions, R.K., Galer, S.J.G., Cohen, A.S., MatteyIsotopic relationships of volatile and lithophile trace elements in continental ultramafic xenolithsContributions to Mineralogy and Petrology, Vol. 110, No. 2-3, pp. 528-538Australia, Arizona, East AfricaUltramafic xenoliths, Geochronology
DS1993-0260
1993
Galer, S.J.G.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
DS202004-0512
2020
Gales, E.Gales, E., Black, B., Elkins-Tanton, E.Carbonatites as a record of the carbon isotope composition of large igneous province outgassing.Earth and Planetary Science Letters, Vol. 535, 116076 11p. PdfRussia, Siberiacarbonatite

Abstract: Large igneous province (LIP) eruptions have been linked in some cases to major perturbations of Earth's carbon cycle. However, few observations directly constrain the isotopic composition of carbon released by LIP magmas because carbon isotopes fractionate during degassing, which hampers understanding of the relative roles of mantle versus crustal carbon reservoirs. Carbonatite magmatism associated with LIPs provides a unique window into the isotopic systematics of LIP carbon because the majority of carbon in carbonatites crystalizes rather than degassing. Although the volume of such carbonatites is small, they offer one of the few available constraints on the mantle carbon originally hosted in other more voluminous magma types. Here, we present new data for the Guli carbonatites in the Siberian Traps. In addition, we compile ?260 published measurements of from carbonatites related to the Deccan Traps and the Paraná-Etendeka. We find no evidence for magmas with carbon isotope ratios lighter than depleted mantle values of ‰ from any of these LIPs, though some carbonatites range to heavier . We attribute relatively heavy in some carbonatites to either slightly 13C-enriched domains in the mantle lithosphere or carbon isotope fractionation in deep, carbon-saturated LIP magma reservoirs. The absence of a light component in LIP magmas supports the view that lithospheric carbon reservoirs must be tapped during cases of LIP magmatism linked with sharp negative carbon isotope excursions and mass extinctions.
DS200912-0635
2009
Gali, S.Robles-Cruz, S.E., Watangua, M., Isidoro, l., Melgarejo, J.C., Gali, S., Olimpo, A.Contrasting compositions and textures of ilmenite in the Catoca kimberlite, Angola, and implications in exploration for diamond.Lithos, In press - available formatted 10p.Africa, AngolaDeposit - Catoca
DS201012-0632
2010
Gali, S.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
DS201212-0113
2012
Gali, S.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
DS201212-0589
2009
Gali, S.Robles-Cruz, S., Lomba, A., Melgarejo, J-C., Gali, S., Olimpio Goncalves, A.The Cucumbi kimberlite, NE Angola: problems to discriminate fertile and barren kimberlites.Revist de la Sociedad de Mineralogia ( in english), pp. 159-160.Africa, AngolaDeposit - Cucumbi
DS201212-0590
2012
Gali, S.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
DS201604-0597
2016
Gali, S.Castilo-Oliver, M., Gali, S., Melgarejo, J.C., Griffin, W.L., Belousova, E., Pearson, N.J., Watangua, M., O'Reilly, S.Y.Trace element geochemistry and U-Pb dating of perovskite in kimberlites of the Lunda Norte province ( NE Angola): petrogenetic and tectonic implications.Chemical Geology, Vol. 426, pp. 118-134.Africa, AngolaGeochronology

Abstract: Perovskite (CaTiO3) has become a very useful mineral for dating kimberlite eruptions, as well as for constraining the compositional evolution of a kimberlitic magma and its source. Despite the undeniable potential of such an approach, no similar study had been done in Angola, the fourth largest diamond producer in Africa. Here we present the first work of in situ U-Pb geochronology and Sr-Nd isotope analyses of perovskite in six Angolan kimberlites, supported by a detailed petrographic and geochemical study of their perovskite populations. Four types of perovskite were identified, differing in texture, major- and trace-element composition, zoning patterns, type of alteration and the presence or absence of inclusions. Primary groundmass perovskite is classified either as anhedral, Na-, Nb- and LREE-poor perovskite (Ia); or euhedral, strongly zoned, Na-, Nb- and LREE-rich perovskite (Ib). Secondary perovskite occurs as reaction rims on ilmenite (IIa) or as high Nb (up to 10.6 wt% Nb2O5) perovskite rims on primary perovskite (IIb). The occurrence of these four types within the Mulepe kimberlites is interpreted as an evidence of a complex, multi-stage process that involved mingling of compositionally different melts. U-Pb dating of these perovskites yielded Lower Cretaceous ages for four of the studied kimberlites: Mulepe 1 (116.2 ± 6.5 Ma), Mulepe 2 (123.0 ± 3.6 Ma), Calonda (119.5 ± 4.3 Ma) and Cat115 (133 ± 10 Ma). Kimberlite magmatism occurred in NE Angola likely due to reactivation of deep-seated translithospheric faults (> 300 km) during the break-up of Gondwana. Sr-Nd isotope analyses of four of these kimberlites indicate that they are Group I kimberlites, which is consistent with the petrological observations.
DS201605-0819
2016
Gali, S.Castillo-Oliver, M., Gali, S., Melgarejo, J.C., Griffin, W.L., Belousova, E., Pearson, N.J., Watangua, M., O'Reilly, S.Y.Trace element geochemistry and U-Pb dating of perovskite in kimberlites of the Lunda Norte province ( NE Angola): petrogenetic and tectonic implications.Chemical Geology, Vol. 426, pp. 118-134.Africa, AngolaDeposit - Alto Cuilo

Abstract: Perovskite (CaTiO3) has become a very usefulmineral for dating kimberlite eruptions, aswell as for constraining the compositional evolution of a kimberlitic magma and its source. Despite the undeniable potential of such an approach, no similar study had been done in Angola, the fourth largest diamond producer in Africa. Here we present the firstwork of in situ U-Pb geochronology and Sr-Ndisotope analyses of perovskite in six Angolan kimberlites, supported by a detailed petrographic and geochemical study of their perovskite populations. Four types of perovskitewere identified, differing in texture,major- and trace-element composition, zoning patterns, type of alteration and the presence or absence of inclusions. Primary groundmass perovskite is classified either as anhedral, Na-, Nb- and LREE-poor perovskite (Ia); or euhedral, strongly zoned, Na-, Nb- and LREE-rich perovskite (Ib). Secondary perovskite occurs as reaction rims on ilmenite (IIa) or as high Nb (up to 10.6 wt% Nb2O5) perovskite rims on primary perovskite (IIb). The occurrence of these four types within the Mulepe kimberlites is interpreted as an evidence of a complex, multi-stage process that involved mingling of compositionally different melts. U-Pb dating of these perovskites yielded Lower Cretaceous ages for four of the studied kimberlites: Mulepe 1 (116.2±6.5Ma),Mulepe 2 (123.0±3.6Ma), Calonda (119.5±4.3 Ma) and Cat115 (133±10Ma). Kimberlite magmatism occurred in NE Angola likely due to reactivation of deep-seated translithospheric faults (N300 km) during the break-up of Gondwana. Sr-Nd isotope analyses of four of these kimberlites indicate that they are Group I kimberlites, which is consistent with the petrological observations.
DS201710-2263
2012
Gali, S.Robles-Cruz, S.E., Melgarejo, J.C., Gali, S., Escayola, M.Major and trace element compositions of indicator minerals that occur as macro and megacrysts, and of xenoliths, from kimberlites in northeastern Angola.Minerals NOTE Date, Vol. 2, pp. 318-337.Africa, Angoladeposits - Tchiuzo, Anomaly 116, Catoca, Alt Cuilo-4, Cuilo-63, Cucumbi-79.

Abstract: In this study, we compare the major- and trace-element compositions of olivine, garnet, and clinopyroxene that occur as single crystals (142 grains), with those derived from xenoliths (51 samples) from six kimberlites in the Lucapa area, northeastern Angola: Tchiuzo, Anomaly 116, Catoca, Alto Cuilo-4, Alto Cuilo-63 and Cucumbi-79. The samples were analyzed using electron probe microanalysis (EPMA) and laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results suggest different paragenetic associations for these kimberlites in the Lucapa area. Compositional overlap in some of the macrocryst and mantle xenolith samples indicates a xenocrystic origin for some of those macrocrysts. The presence of mantle xenocrysts suggests the possibility of finding diamond. Geothermobarometric calculations were carried out using EPMA data from xenoliths by applying the program PTEXL.XLT. Additional well calibrated single-clinopyroxene thermobarometric calculations were also applied. Results indicate the underlying mantle experienced different equilibration conditions. Subsequent metasomatic enrichment events also support a hypothesis of different sources for the kimberlites. These findings contribute to a better understanding of the petrogenetic evolution of the kimberlites in northeastern Angola and have important implications for diamond exploration.
DS201711-2506
2017
Gali, S.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.
DS201906-1342
2019
Gali, S.Robles Cruz, S., Melgarejo, J.C., Gali, S.Revisiting the complexity of kimberlites from northeastern Angola.GAC/MAC annual Meeting, 1p. Abstract p. 166.Africa, Angoladeposit - Catoca

Abstract: The tectonic setting of northeastern Angola was influenced by the opening of the South Atlantic Ocean, which reactivated deep NE-SW-trending faults during the early Cretaceous. The new interpretation of a kimberlitic pulse during the middle of the Aptian and the Albian, which provides precise data on the age of a significant diamond-bearing kimberlite pulse in Angola, will be an important guide in future diamond exploration. These findings contribute to a better understanding of the petrogenetic evolution of the kimberlites in northeastern Angola and have important implications for diamond exploration. Six kimberlite pipes within the Lucapa structure in northeastern Angola have been investigated using major and trace element geochemistry of mantle xenoliths, macro- and megacrysts. Geothermobarometric calculations were carried out using xenoliths and well-calibrated single crystals of clinopyroxene. Geochronological and isotopic studies were also performed where there were samples available of sufficient quality. Results indicate that the underlying mantle experienced variable conditions of equilibration among the six sites. Subsequent metasomatic enrichment events also support a hypothesis of different sources for these kimberlites. The U/Th values suggest at least two different sources of zircon crystals from the Catoca suite. These different populations may reflect different sources of kimberlitic magma, with some of the grains produced in U- and Th-enriched metasomatized mantle units, an idea consistent with the two populations of zircon identified on the basis of their trace element compositions. This research shows the absence of fresh Mg-rich ilmenite in the Catoca kimberlite (one of the largest bodies of kimberlite in the world), as well as the occurrence of Fe3+-rich ilmenite, do not exclude the presence of diamond in the kimberlite. This is a new insight into the concept of ilmenite and diamond exploration and leads to the conclusion that compositional attributes must be evaluated in light of textural attributes.
DS1988-0588
1988
Galii, G.A.Rybalko, S.I., Galii, G.A., Gamarnik, M.Ya., et al.Electron optical studies of zircon from kimberlites.(Russian)Ontogeniya Mineralov I Teknol Mineral Kiev.(Russian), pp. 160-165RussiaMircoprobe, Zircon
DS201412-0261
2014
Galillou, E.Galillou, E., Post, J.E., Steele, A., Butler, J.E.Constrains on highly strained pink diamonds by high spatial resolution FTIR and Raman mapping.Geological Society of America Conference Vancouver Oct. 19-22, 1p. AbstractTechnologyPink diamond colour
DS200612-0421
2006
Galimov, E.Galimov, E., Kudin, A., Skorobogatskii, V., Plotnichenko, V., Bondarev, O., Zarubin, B., Strazdovskii, V., Aronin, A., Fisenko, A., Bykov, I., Barinov, A.Experimental corrobation of the synthesis of diamond in the cavitation process.Doklady Physical Chemistry, Vol. 49, 3, pp. 150-153.TechnologyDiamond synthesis
DS1970-0548
1972
Galimov, E.M.Kovalskiy, V.V., Galimov, E.M., et al.Isotopic Composition of Carbon from Colored Yakutian DiamondDoklady Academy of Science USSR, Earth Science Section., Vol. 203, No. 1-6, PP. 118-119.RussiaKimberlite, Geochronology, Genesis, Carbonado
DS1975-0747
1978
Galimov, E.M.Galimov, E.M., Kaminskiy, F.V., Ivanovskaya, I.N.Carbon Isotope Compositions of Diamonds from the Urals, Timan, Sayan, the Ukraine, and Elsewhere.Geochemistry International, Vol. 15, No. 2, PP. 11-18.RussiaBlank
DS1975-1024
1979
Galimov, E.M.Galimov, E.M., Klyuyev, Yu.A., et al.Correlation of Isotopic Distribution with Morphology and Lattice Structure in Diamonds from Yakutia Placers.Doklady Academy of Science USSR, Earth Science Section., Vol. 249, No. 1-6, PP. 153-156.Russia, YakutiaDiamond Morphology
DS1975-1042
1979
Galimov, E.M.Gurkina, G.A., Ivanovskaya, I.N., Kaminskiy, F.V., Galimov, E.M.The Distribution of Carbon Isotopes in Diamond Crystals.(russian)Geochemistry International (Geokhimiya)(Russian), Vol. 1979, No. 12, pp. 1897-1905RussiaBlank
DS1980-0134
1980
Galimov, E.M.Galimov, E.M., Ivanovskaya, I.N., et al.New Dat a on the Isotope Composition of Carbon in Diamonds from Various regions of the Soviet Union.Tsnigri, No. 153, PP. 19-29.RussiaBlank
DS1982-0308
1982
Galimov, E.M.Kaminskiy, F.V., Galimov, E.M., et al.Bort With Garnet from the Mir Pipe, YakutiaDoklady Academy of Science USSR, Earth Science Section., Vol. 256, No. 3, PP. 115-117.Russia, YakutiaCrystallcgraphy, Petrography
DS1984-0288
1984
Galimov, E.M.Galimov, E.M.13c/12c of Diamonds. Vertical Zonality of Diamond Formation InthelithosphereIn: Proceedings of the 27th. International Geological Congress held Moscow, August, Vol. 11, Geochemistry and Cosmochemistry, pp. 279-308GlobalDiamond Morphology
DS1984-0289
1984
Galimov, E.M.Galimov, E.M.Variations of Isotopic Composition of Diamond FormationGeokhemiya., No. 8, AUGUST PP. 1091-1118.RussiaBlank
DS1985-0209
1985
Galimov, E.M.Galimov, E.M.The relation between formation conditions and variations in isotope composition of diamondsGeochemistry International, Vol. 22, No. 1, pp. 118-142RussiaDiamond Morphology
DS1985-0210
1985
Galimov, E.M.Galimov, E.M.Some Evidence of Reality of the Cavitation Synthesis of Diamonds in Nature.Geockhimiya., No. 4, PP. 456-471. 66 REFS.RussiaDiamond Morphology, Crystallography
DS1985-0211
1985
Galimov, E.M.Galimov, E.M., Kaminsky, F.V., Kodina, L.A.New Dat a on Isotopic Composition of Carbon of CarbonadoGeochemistry International (Geokhimiya)., No. 5, MAY PP. 723-725.RussiaGeochemistry
DS1986-0260
1986
Galimov, E.M.Galimov, E.M.Some proofs of the reality of cavitational synthesis of diamonds in nature #2 (1986)Geochemistry International, No. 4, pp. 99-112RussiaDiamond morphology, geochemistry
DS1988-0233
1988
Galimov, E.M.Galimov, E.M.Carbon geochemistryGeochemistry International, Vol. pp. 94-110RussiaGeochemistry, Carbon
DS1988-0234
1988
Galimov, E.M.Galimov, E.M., Botkunov, A.I., Bannikova, L.A., et al.Isotopic composition of carbon from gas and bitumens of gas-liquid inclusions in garnet from the Mir kimberlite pipeDoklady Academy of Science USSR, Earth Science Section, Vol. 301, No. 4, July-Aug. pp. 184-185RussiaGeochronology, Carbon -Mir pipe
DS1989-0460
1989
Galimov, E.M.Galimov, E.M., Botkunov, A.I., Garanin, V.K.Carbon bearing fluid inclusions in olivine and garnet from the Udachnaya kimberlite pipe.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 7, pp. 1011-1015RussiaDiamond inclusions, Garnet analyses
DS1989-0461
1989
Galimov, E.M.Galimov, E.M., Botkunov, A.I., Garanin, V.K., Spasennykh, M. Yu.Carbon-containing fluid inclusions in garnet and olivine from Kimberlites of the Udachnaya pipe. (USSR)(Russian)Geochemistry International (Geokhimiya), (Russian), No. 7, pp. 1011-1015RussiaFluid inclusions, Garnet
DS1989-0462
1989
Galimov, E.M.Galimov, E.M., Kaminskiy, F.V., Maltsev, K.A., Sobolev, N.V.Relation of carbon isotopic composition with parageneses of mineral inclusions in diamonds in paired kimberlite pipes.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 5, pp. 754-758RussiaGeochronology - C Isotope, Diamond inclusions
DS1989-0463
1989
Galimov, E.M.Galimov, E.M., Sobolev, N.V., Yefimova, E.S.Isotopic composition of carbon of diamond bearing mineral inclusions From the northern Urals placers.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 9, pp. 1363-1370RussiaDiamond inclusions, Geochronology
DS1989-0464
1989
Galimov, E.M.Galimov, E.M., Soloviova, L.V., Belomestnykh, A.V.Carbon isotope composition of different forms of carbon in eclogite from Mir kimberlite pipe.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 305, No. 4, pp. 953-956RussiaEclogite, Geochronology
DS1989-0465
1989
Galimov, E.M.Galimov, E.M., Solovyeva, L.V., Belomesnyy, A.B.Isotopic composition of various forms of carbon in eclogite from kimberlite of the Mir pipeDoklady Academy of Sciences USSR, Earth Science Section, Vol. 305, No. 2, March-April pp. 204-206RussiaCarbon, Eclogite -Mir pipe
DS1989-0466
1989
Galimov, E.M.Galimov, E.M., Ukhanov, A.V.Nature of carbonate component of kimberlites.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 3, March pp. 337-348RussiaGeochemistry, Carbonate mineralogy
DS1989-0467
1989
Galimov, E.M.Galimov, E.M., Ukhanov, A.V.The carbonate component in kimberlitesGeochemistry International, Vol. 26, No. 10, pp. 14-23RussiaGeochronology, Carbonate-kimberlite
DS1989-1422
1989
Galimov, E.M.Sobolev, N.V., Galimov, E.M., Smith, C.B., Yefimova, E.S., MaltsevA comp study of the morphology, inclusions and C I composition of diamondsSoviet Geology and Geophysics, Vol. 30, No. 12, pp. 1-19AustraliaMicrodiamonds, Alluvial diamonds
DS1990-0505
1990
Galimov, E.M.Galimov, E.M., Botkunov, A.I., Garanin, V.K.Carbon bearing fluid inclusions in olivine and garnet from Udachnaya pipekimberlitesGeochemistry International, Vol. 27, No. 2, February pp. 87-90RussiaGeochronology, Carbon inclusions
DS1990-0506
1990
Galimov, E.M.Galimov, E.M., Kaminisky, F.V., Maltsev, K.A., Sobolev, N.V.The relation between delta 13 C and mineral inclusion assemblages in diamonds from paired kimberlite pipesGeochemistry International, Vol. 26, No. 12, pp. 134-137RussiaDiamond inclusions, carbon, Delta 13 C analyses
DS1990-0507
1990
Galimov, E.M.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
DS1990-0508
1990
Galimov, E.M.Galimov, E.M., Sobolev, N.V., Yefimova, E.S., Shemanina, Ye.I.Carbon isotope composition of inclusion bearing diamonds from north UralplacersGeochemistry Int, Vol. 27, No. 4, pp. 131-138RussiaGeochronology CI, Placers
DS1990-0509
1990
Galimov, E.M.Galimov, E.M., Solovyeva, L.V., Belomestnykh, A.V.Carbon isotope composition of metasomatized mantle rocksGeochemistry International, Vol. 26, No. 11, April pp. 38-43RussiaMantle, Geochronology
DS1991-0526
1991
Galimov, E.M.Galimov, E.M.Isotope fractionation related to kimberlite magmatism and diamond formation #1Geochimica et Cosmochimica Acta, Vol. 55, pp. 1697-1708GlobalKimberlite magaM., Diamond genesis
DS1991-0527
1991
Galimov, E.M.Galimov, E.M.Isotope fractionation related to kimberlite magmatism and diamond formation #2Proceedings of Fifth International Kimberlite Conference held Araxa June, pp. 502-504RussiaGeochronology, Diamond genesis
DS1991-0528
1991
Galimov, E.M.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
DS1991-1042
1991
Galimov, E.M.Maltsev, K.A., Galimov, E.M.Isotope distribution in hydrogen of diamondDoklady Academy of Science USSR, Earth Science Section, Vol. 308, No. 5, pp. 229-230RussiaDiamond inclusions, Hydrogen
DS1993-0859
1993
Galimov, E.M.Krot, A.N., Poskukojovsky, T.V., Guseva, E.V., Galimov, E.M., Botkunov, A.I. et.Genesis of the garnets containing hydrocarbon inclusions (Mir kimberlitepipe). (Russian)Geochemistry International (Geokhimiya), (Russian), No. 6, June pp. 891-899RussiaGeochemistry -garnets, Deposit -Mir
DS1993-1498
1993
Galimov, E.M.Sobolev, N.V., Galimov, E.M., Efimova, E.S., Sobolev, E.V.Crystalline inclusions, isotopes carbon, nitrogen centers in diamonds, features of garnet from Madjgawan.Russian Geology and Geophysics, Vol. 34, No. 12, pp. 77-83.IndiaDiamond inclusions, Deposit -Madjgawan
DS1994-0562
1994
Galimov, E.M.Galimov, E.M., et al.The carbon isotope composition of north Chin a platform diamonds.(Russian)Doklady Academy of Sciences Nauk., (Russian), Vol. 337, No. 4, August pp. 467-468.ChinaGeochronology, Diamond, isotope -carbon
DS1994-0563
1994
Galimov, E.M.Galimov, E.M., Zakharch, O.D., Maltsev, K.A., Makhin, A.I.The isotopic composition of carbon in diamonds from the kimberlitic pipe sat Archangelsk.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 1, pp. 67-74.Russia, Yakutia, ArkangelskGeochronology, Diamond inclusions -carbon
DS1994-0564
1994
Galimov, E.M.Galimov, E.M., Zakharchenko, K.A., et al.Carbon isotope composition of diamonds from Arkangel region kimberlitepipes.Geochemistry International, Vol. 31, No. 8, pp. 71-78.Russia, ArkangelskDiamond geochronology, Deposit -Arkangel
DS1995-0575
1995
Galimov, E.M.Galimov, E.M., Bao Yannan, K.A., Maltsev, K.A., SmirnovaIsotopic composition of diamonds from the North Chinese PlatformDoklady Academy of Sciences Acad. Science Russia, Vol. 331A, No. 6, June pp. 189-192.ChinaGeochronology, Diamonds
DS1998-0461
1998
Galimov, E.M.Galimov, E.M.Growth of the earth's core as a source of its internal energy and a Factor of mantle redox evolution.Geochemistry International, Vol. 36, No. 8, Aug. 1, pp. 673-6.MantleRedox
DS1998-0462
1998
Galimov, E.M.Galimov, E.M., Mirononv, A.G., Shiryaev, A.A.Origin of carbon in Diamondiferous carbonized ultrabasites at the EasternSayan.Doklady Academy of Sciences, Vol. 363A, No. 9, Nov-Dec. pp. 1304-6.Russia, SayanMetamorphic rocks, Carbon, diamond
DS1998-1344
1998
Galimov, E.M.Shiryaev, A.A., Galimov, E.M., Sobolev, N.V., KolesovTrace elements in inclusion free diamonds from Venezuela and Arkhangelskdeposits.7th International Kimberlite Conference Abstract, pp. 811-13.Russia, Kola, VenezuelaDiamond formation, genesis, Mineral inclusions
DS2003-1269
2003
Galimov, E.M.Shiryaev, A., Izraeli, E.S., Hauri, E.., Galimov, E.M., Navon, O.Fluid inclusions in Brazilian coated diamonds8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractBrazilDiamonds - inclusions
DS200512-0309
2005
Galimov, E.M.Galimov, E.M.Redox evolution of the Earth caused by a multi stage formation of its core.Earth and Planetary Science Letters, Vol. 233, 3-4, May 15, pp. 263-276.MantleGeothermometry, core-mantle boundary
DS200612-0135
2006
Galimov, E.M.Bibikova, E.V., Galimov, E.M.Time and geodynamic constraints on the formation and evolution of the early Earth's crust.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleGeodynamics
DS200812-0380
2008
Galimov, E.M.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
DS200812-0596
2008
Galimov, E.M.Kostitsyn, Y.A., Bibikova, E.V., Galimov, E.M.Finite speed of mantle homogenization and Hf W assessments of the Earth's core age.Goldschmidt Conference 2008, Abstract p.A493.MantleGeochronology
DS200812-0839
2008
Galimov, E.M.Palazhchenko, O.V., Garanin, V.K., Galimov, E.M.Isotope and mineralogical study of diamonds from northwestern Russia.Goldschmidt Conference 2008, Abstract p.A718.Russia, Kola Peninsula, ArchangelDeposit - Lomonosov, Grib
DS200912-0239
2009
Galimov, E.M.Galimov, E.M.Advances in geochemistry during the last four decades: a personal perspective.Applied Geochemistry, Vol. 24, 6, pp. 1048-1051.TechnologyGeochemistry
DS201608-1404
2016
Galimov, E.M.Galimov, E.M., Sevastyanov, V.S., Karpova, G.A., Shilobreeva, S.N., Maksimov, A.P.Microcrystalline diamonds in the oceanic lithosphere and their nature. MicrodiamondsDoklady Earth Sciences, Vol. 469, 1, pp. 670-673.RussiaTolbachik Volcano

Abstract: The carbon isotope composition of microdiamonds found in products of the Tolbachik Volcano eruption, Kamchatka (porous lavas and ash), was studied. The isotope composition of microdiamonds (with an average value of ?13C =-25.05‰) is close to that of microsized carbon particles in lavas (from-28.9 to-25.3‰). The general peculiarities of the diamond-forming environment include (1) no evidence for high pressure in the medium; (2) a reduced environment; and (3) mineralogical evidence for the presence of a fluid. The geochemical data characterizing the type of diamonds studied allow us to suggest that they were formed in accordance with the mechanism of diamond synthesis during cavitation in a rapidly migrating fluid, which was suggested by E.M. Galimov.
DS202005-0731
2020
Galimov, E.M.Galimov, E.M., Kaminsky, F.V., Shilobreeva, S.N., Sevastyanov, V.S., Voropaev, S.A., Khachatryan, G.K., Wirth, R., Schreiber, A., Saraykin, V.V., Karpov, G.A., Anikin, L.P.Enigmatic diamonds from the Tolbachik volcano, Kamchatka.American Mineralogist, Vol. 105, pp. 498-509. pdfRussiadeposit - Tolbachik

Abstract: Approximately 700 diamond crystals were identified in volcanic (mainly pyroclastic) rocks of the Tolbachik volcano, Kamchatka, Russia. They were studied with the use of SIMS, scanning and transmission electron microscopy, and utilization of electron energy loss spectroscopy and electron diffraction. Diamonds have cube-octahedral shape and extremely homogeneous internal structure. Two groups of impurity elements are distinguished by their distribution within the diamond. First group, N and H, the most common structural impurities in diamond, are distributed homogeneously. All other elements observed (Cl, F, O, S, Si, Al, Ca, and K) form local concentrations, implying the existence of inclusions, causing high concentrations of these elements. Most elements have concentrations 3-4 orders of magnitude less than chondritic values. Besides N and H, Si, F, Cl, and Na are relatively enriched because they are concentrated in micro- and nanoinclusions in diamond. Mineral inclusions in the studied diamonds are 70-450 nm in size, round- or oval-shaped. They are represented by two mineral groups: Mn-Ni alloys and silicides, with a wide range of concentrations for each group. Alloys vary in stoichiometry from MnNi to Mn2Ni, with a minor admixture of Si from 0 to 5.20-5.60 at%. Silicides, usually coexisting with alloys, vary in composition from (Mn,Ni)4Si to (Mn,Ni)5Si2 and Mn5Si2, and further to MnSi, forming pure Mn-silicides. Mineral inclusions have nanometer-sized bubbles that contain a fluid or a gas phase (F and O). Carbon isotopic compositions in diamonds vary from -21 to -29‰ ?13CVPDB (avg. = -25.4). Nitrogen isotopic compositions in diamond from Tolbachik volcano are from -2.32 to -2.58‰ ?15NAir. Geological, geochemical, and mineralogical data confirm the natural origin of studied Tolbachik diamonds from volcanic gases during the explosive stage of the eruption.
DS202102-0191
2021
Galimov, E.M.Galimov, E.M., Kaminsky, F.V.Diamond in oceanic lithosphere. Volcanic diamonds and diamonds in ophiolites.Geochemistry International, Vol. 59, 1, pp. 1-11. pdfRussiadeposit - Tolbachik, Kamchatka
DS200712-0872
2007
Galindo, C.Rapela, C.W., Pankhurst, R.J., Casquet, C., Fanning, C.M., Baldor Casado, E.G., Galindo, C., DahlquistThe Rio de la Plat a craton and the assembly of SW Gondwana.Earth Science Reviews, In press availableSouth America, BrazilTectonics
DS200712-0873
2007
Galindo, C.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
DS1985-0212
1985
Galinov, E.M.Galinov, E.M., Kaminskiy, F.V., Kodina, L.A.New Dat a on Carbonado Carbon Isotope CompositionsGeochemistry International, Vol. 22, No. 9, pp. 18-21Russia, BrazilLonsdaleite, Morphology
DS1975-0281
1976
Galipeau, J.M.Galipeau, J.M.Petrochemistry of the Virginia Dale Ring Dike ComplexMsc. Thesis, University North Carolina., United States, Wyoming, Colorado, State Line, Rocky MountainsRegional Studies
DS1975-1025
1979
Galipeau, J.M.Galipeau, J.M., Ragland, P.C.Whole Rock Chemical Constraints on the Origin of the Virginia Dale Ring Dike Complex.Geochemical Journal, Vol. 13, No. 5, NOVEMBER PP. 207-216.United States, Colorado, Wyoming, State Line, Rocky MountainsGeochemistry
DS201802-0245
2017
Galkin, A.S.Kiselev, G.P., Yakovlev, E.Yu., Druzhinin, S.V., Galkin, A.S.Distribution of radioactive isotopes in rock and ore of Arkhanelskava pipe from the Arkhanelsk diamond province.Geology of Ore Deposits, Vol. 59, pp. 391-406.Russia, Archangeldeposit - Arkhangelskaya

Abstract: The contents of radioactive elements and the uranium isotopic composition of kimberlite in the Arkhangelskaya pipe at the M.V. Lomonosov deposit and of nearby country rocks have been studied. A surplus of 234U isotope has been established in rocks from the near-pipe space. The high ? = 234U/238U ratio is controlled by the geological structure of the near-pipe space. A nonequilibrium uranium halo reaches two pipe diameters in size and can be regarded as a local ore guide for kimberlite discovery. The rocks in the nearpipe space are also characterized by elevated or anomalous U, Th, and K contents with respect to the background.
DS1990-0419
1990
Galkin, V.M.Doroshev, A.M., Galkin, V.M., Turkin, A.I., Kalinin, A.A.Thermal expansion of garnets of pyrope grossularite and pyrope Knorringiteseries.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 1, January 1990, pp. 152-155RussiaGarnet-pyrope, Geochemistry
DS1990-0420
1990
Galkin, V.M.Doroshev, A.M., Galkin, V.M., Turkin, A.I., Kalinin, A.A.Thermal expansion in the pyrope-grossular and pyrope-knorringite garnetseriesGeochemistry International, Vol. 27, No. 8, pp. 144-149RussiaMineralogy, Pyrope
DS201012-0140
2010
Gall, L.De Hoog, J.C.M., Gall, L., Cornell, D.H.Trace element geochemistry of mantle olivine and application to mantle petrogenesis and geothermometry.Chemical Geology, In press available formatted 20p.MantleGeobarometry
DS1992-0508
1992
Gall, Q.Gall, Q.Precambrian paleosols in CanadaCanadian Journal of Earth Sciences, Vol. 29, No. 12, December pp. 2530-2536Northwest Territories, Ontario, Manitoba, SaskatchewanWeathering, Laterites, paleosols
DS1992-0509
1992
Gall, Q.Gall, Q.Precambrian paleosols in CanadaCanadian Journal of Earth Sciences, Vol.29, pp. 2350-56.CanadaPaleosols - location list, Structure - microstructures
DS1994-0565
1994
Gall, Q.Gall, Q.The Proterozoic The lon paleosol, Northwest Territories, CanadaPrecambrian Research, Vol. 68, No. 1/2, June pp. 115-138Northwest TerritoriesProterozoic, Thelon paleosol, sedimentary
DS2003-0435
2003
Gall, S.Gall, S.The Bushmen of the KalahariThe Ecologist, Vol. 33, No. 7, pp. 28-31.BotswanaHistory
DS200412-0602
2003
Gall, S.Gall, S.The Bushmen of the Kalahari.The Ecologist, Vol. 33, no. 7, pp. 28-31.Africa, BotswanaHistory
DS201212-0591
2012
Galla, S.Robles-Cruz, S.E., Galla, S., Escayoblab, M., Melgarejoa, J.C.Heterogeneous mantle beneath the Lunda area in Angola.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, AngolaDeposit - Lunda area
DS201809-2100
2018
Gallacher, R.Tepp, G., Ebinger, C.J., Zal, H., Gallacher, R., Accardo, N., Shillington, D.J., Gaherty, J., Keir, D., Nyblade, A.A., Mbogoni, G.J., Chindandali, P.R.N., Ferdinand-Wambura, R., Mulibo, G.D., Kamihanda, G.Seismic anistrotropy of the Upper mantle below the western rfit, East Africa.Journal of Geophysical Research, Vol. 123, 7, pp. 5644-5660.Africa, east Africageophysics - seismic

Abstract: Although the East African rift system formed in cratonic lithosphere above a large?scale mantle upwelling, some sectors have voluminous magmatism, while others have isolated, small?volume eruptive centers. We conduct teleseismic shear wave splitting analyses on data from 5 lake?bottom seismometers and 67 land stations in the Tanganyika?Rukwa?Malawi rift zone, including the Rungwe Volcanic Province (RVP), and from 5 seismometers in the Kivu rift and Virunga Volcanic Province, to evaluate rift?perpendicular strain, rift?parallel melt intrusion, and regional flow models for seismic anisotropy patterns beneath the largely amagmatic Western rift. Observations from 684 SKS and 305 SKKS phases reveal consistent patterns. Within the Malawi rift south of the RVP, fast splitting directions are oriented northeast with average delays of ~1 s. Directions rotate to N?S and NNW north of the volcanic province within the reactivated Mesozoic Rukwa and southern Tanganyika rifts. Delay times are largest (~1.25 s) within the Virunga Volcanic Province. Our work combined with earlier studies shows that SKS?splitting is rift parallel within Western rift magmatic provinces, with a larger percentage of null measurements than in amagmatic areas. The spatial variations in direction and amount of splitting from our results and those of earlier Western rift studies suggest that mantle flow is deflected by the deeply rooted cratons. The resulting flow complexity, and likely stagnation beneath the Rungwe province, may explain the ca. 17 Myr of localized magmatism in the weakly stretched RVP, and it argues against interpretations of a uniform anisotropic layer caused by large?scale asthenospheric flow or passive rifting.
DS201905-1056
2019
Gallacher, R.Lavayssiere, A., Drooff, C., Ebinger, C., Gallacher, R., Illsley-Kemp, F., Finnigan, Oliva, S.J., Keir, D.Deep extent and kinematics of faulting in the southern Tanganyika Rift, Africa.Tectonics, Vol. 38, 3, pp. 842-862.Africarifting

Abstract: Unusually deep earthquakes occur beneath rift segments with and without surface expressions of magmatism in the East African Rift system. The Tanganyika rift is part of the Western rift and has no surface evidence of magmatism. The TANG14 array was deployed in the southern Tanganyika rift, where earthquakes of magnitude up to 7.4 have occurred, to probe crust and upper mantle structure and evaluate fault kinematics. Four hundred seventy?four earthquakes detected between June 2014 and September 2015 are located using a new regional velocity model. The precise locations, magnitudes, and source mechanisms of local and teleseismic earthquakes are used to determine seismogenic layer thickness, delineate active faults, evaluate regional extension direction, and evaluate kinematics of border faults. The active faults span more than 350 km with deep normal faults transecting the thick Bangweulu craton, indicating a wide plate boundary zone. The seismogenic layer thickness is 42 km, spanning the entire crust beneath the rift basins and their uplifted flanks. Earthquakes in the upper mantle are also detected. Deep earthquakes with steep nodal planes occur along subsurface projections of Tanganyika and Rukwa border faults, indicating that large offset (?5 km) faults penetrate to the base of the crust, and are the current locus of strain. The focal mechanisms, continuous depth distribution, and correlation with mapped structures indicate that steep, deep border faults maintain a half?graben morphology over at least 12 Myr of basin evolution. Fault scaling based on our results suggests that M > 7 earthquakes along Tanganyika border faults are possible.
DS1998-0172
1998
GallagherBrown, R.W., Gallagher, Griffin, Ryan, De Wit, BeltonKimberlites, accelerated erosion and evolution of the lithospheric mantle beneath Kaapvaal - mid-Cretaceous..7th International Kimberlite Conference Abstract, pp. 105-107.South AfricaHeat flow data, uplift, Kaapvaal Craton
DS1993-0920
1993
Gallagher, A.J.Livo, K.E., Gallagher, A.J.REMAPP-PC remote sensing image processing software for MS-DIS personalcomputers, version 2.00/United States Geological Survey (USGS) Open File, No. 91-0449 A-G each disc $ 6.00 = $ 42.00GlobalComputer, Program -REMAPP-PC.
DS1992-0510
1992
Gallagher, K.Gallagher, K., Hawkesworth, C.Dehydration melting and the generation of continental flood basaltsNature, Vol. 358, no 6381, July 2, pp. 57-59Brazil, NamibiaFlood basalts, Dehydration
DS1993-0643
1993
Gallagher, K.Hawkesworth, C.J., Gallagher, K., et al.Mantle hotspots, plumes and regional tectonics as causes of intraplatemagmatism.Terra Nova, Vol. 5, No. 6, pp. 552-559.MantleHot spots, subduction, melting, Tectonics
DS1993-0644
1993
Gallagher, K.Hawkesworth, C.J., Gallagher, K., Hergt, J.M., McDermott, F.Trace element fractionation processes in the generation of island arcbasaltsRoyal Society Transactions, Physical Sciences, Ser. A, Vol. 342, No. 1663, January 15, pp. 179-191MantleSubduction, Magmas
DS1993-0645
1993
Gallagher, K.Hawkesworth, K., Gallagher, K., Hergt, J.M., McDermott, F.Mantle and slab contribution in arc magmasAnnual Review of Earth and Planetary Sciences, Vol. 21, pp. 175-204MantleSubduction, Tectonics
DS1994-0218
1994
Gallagher, K.Brown, R., Gallagher, K., Duane, M.A quantitative assessment of the effects of magmatism on the thermal history of the Karoo sediment sequenceJournal of African Earth Sciences, Vol. 18, No. 3, April pp. 245-254South AfricaMagmatism, Karoo sedimentology
DS1994-0219
1994
Gallagher, K.Brown, R., Gallagher, K., Duane, M.A quantitative assessment of effects of magmatism on the thermal history Of the Karoo sedimentary sequenceJourn. African Earth Sciences, Vol. 18, No. 3, pp. 227-243South AfricaMagmatism, Paleotemperatures
DS1994-0566
1994
Gallagher, K.Gallagher, K., Hawkesworth, C.Mantle plumes, continental magmatism and asymmetry in the South AtlanticEarth and Planetary Science Letters, Vol. 123, pp. 105-17.GlobalPlumes, Magmatism
DS1994-0743
1994
Gallagher, K.Hawkesworth, C., Gallagher, K., Turner, S.Causes of melt generation in the sub-continental mantleMineralogical Magazine, Vol. 58A, pp. 394-395. AbstractMantleMantle plumes, Magma
DS1994-0745
1994
Gallagher, K.Hawkesworth, C.J., Gallagher, K., Hergt, J.M., McDermottDestructive plate margin magmatism: geochemistry and melt generationLithos, Vol. 33, No. 1-3, October pp. 169-188.MantleGeotectonics, geodynamics, Geochemistry
DS1996-0182
1996
Gallagher, K.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
DS2000-0394
2000
Gallagher, K.Hawkesworth, C.J., Gallagher, K., Turner, S.P.Tectonic controls on magmatism associated with continental break up: an example from Parana-Etendeka.Earth and Planetary Science Letters, Vol. 179, No. 2, June 30, pp. 335-50.BrazilTectonics, Magmatism
DS2001-0913
2001
Gallagher, K.Petford, N., Gallagher, K.Partial melting of mafic amphibilitic lower crust by periodic influx of basaltic magmaEarth and Planetary Science Letters, Vol. 193, No. 3-4, pp.483-99.MantleMagmatism
DS2002-0870
2002
Gallagher, K.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
DS200912-0118
2009
Gallagher, K.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
DS201502-0046
2014
Gallagher, K.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.
DS202102-0234
2020
Gallagher, K.Wildman, M., Gallagher, K., Chew, D., Carter, A.From sink to source: using offshore thermochronometric data to extract onshore erosion signals in Namibia.Basin Research, doi.org/10.111 /bre.12527 23p. PdfAfrica, NamibiaThermochron, temperature logging

Abstract: Products of onshore passive continental margin erosion are best preserved in offshore sedimentary basins. Therefore, these basins potentially hold a recoverable record of the onshore erosion history. Here, we present apatite fission track (AFT) data for 13 samples from a borehole in the southern Walvis basin, offshore Namibia. All samples show AFT central ages older or similar to their respective stratigraphic ages, while many single grain ages are older, implying none of the samples has been totally annealed post?deposition. Furthermore, large dispersion in single grain ages in some samples suggests multiple age components related to separate source regions. Using Bayesian mixture modelling we classify single grain ages from a given sample to particular age components to create ‘subsamples’ and then jointly invert the entire dataset to obtain a thermal history. For each sample, the post?depositional thermal history is required to be the same for all age components, but each component (‘subsample’) has an independent pre?depositional thermal history. With this approach we can resolve pre? and post?depositional thermal events and identify changes in sediment provenance in response to the syn? and post?rift tectonic evolution of Namibia and southern Africa. Apatite U?Pb and compositional data obtained during the acquisition of LA?ICP?MS FT data are also presented to help track changes in provenance with time. We constrain multiple thermal events linked to the exhumation and burial history of the continental and offshore sectors of the margin over a longer timescale than has been possible using only onshore AFT thermochronological data.
DS1960-0344
1963
Gallagher, M.J.Gallagher, M.J.Lamprophyre Dykes from ArgylMineralogical Magazine., Vol. 33, PP. 415-430.Australia, Western AustraliaRelated Rocks
DS1994-0839
1994
Gallagher, R.Jaques, A.L., Wyborn, L.A.L., Gallagher, R.The role of geographic information systems, empirical modelling and expert systems in metallogenic research.Geological Society of Australia Abstracts, No. 37, p. 196-7.Australia, Western AustraliaGIS, Metallogeny, alkaline rocks
DS201212-0226
2012
Gallagher, R.J.Gallagher, R.J., Bastow, I.D.Receiver function constraints on crustal structure in Cameroon: implications for basement development and magmatism along the Cameroon Volcanic Line.Tectonics, in preparationAfrica, CameroonGeophysics - seismics
DS201312-0290
2013
Gallagher, W.Gallagher, W.Where have all the miners gone? Aboriginals are now masters of Canada's resource agenda says new book…. Bill Gallagher Resource rules: fortune and folly on Canada's road to resources.Canadian Mining Journal, Feb/March pp. 50-53. Gallagher's book is self published.CanadaCSR
DS1950-0026
1950
Gallagher, W.S.Gallagher, W.S., Kuttner, R.The Application of Long Hole Drilling to Diamond MiningAssociation MINE MANAGERS TRANSVAAL Circular, No. 8/50, 42P.South AfricaMining
DS1960-0045
1960
Gallagher, W.S.Gallagher, W.S.Mining Blue Ground at de BeersEngineering and Mining Journal, Vol. 161, PP. 92-102.South AfricaMining Methods, Recovery
DS1960-0046
1960
Gallagher, W.S.Gallagher, W.S., Loftus, W.K.B.Block Caving Practice at de Beers Consolidated Mines LimitedSouth African Institute of Mining and Metallurgy. Journal, Vol. 61, APRIL, PP. 405-429.South AfricaMining Methods, Recovery, Evaluation, Diamond, Kimberlite Pipes
DS1960-0047
1960
Gallagher, W.S.Gallagher, W.S., Sandilands, J.S., Howell, T.V.Native Administration in the Kimberley Diamond MinesSouth African Institute of Mining and Metallurgy. Journal, Vol. 60, No. 5, PP. 500-502.South AfricaPolitics, Mining Methods, Recovery
DS1960-0242
1962
Gallagher, W.S.Gallagher, W.S., Loftus, W.K.B.Yielding Arches for Support of Block Cave Scraper DriftsAssociation MINE MANAGERS STH. AFR. 1960/1961, PP. 439-450.South AfricaMining Methods
DS2002-1294
2002
Gallagherm K.Raab, M.J., Brown, R.W., Gallagherm K., Carter, A., Weber, K.Late Cretaceous reactivation of major crustal shear zones in northern Namibia: constraints from apatite fission track analysis.Tectonophysics, Vol. 349, No. 1-4, pp.75-92.NamibiaGeochronology, Tectonics
DS200712-0343
2007
Galland, O.Galland, O., Cobbold, P.R., De Bremond d'Ars, J., Hallot, E.Rise and emplacement of magma during horizontal shortening of the brittle crust: insights from experiments.Journal of Geophysical Research, Vol. 112, B6 B06402MantleMagmatism
DS201112-0342
2011
Gallardo, L.A.Gallardo, L.A., Meju, M.A.Structure coupled multiphysics imaging in geophysical sciences.Reviews of Geophysics, Vol. 49, 1, RG1003TechnologyGeophysics - not specific to diamonds
DS2000-0137
2000
Gallart, J.Carbonell, R., Gallart, J., Knapp, J.Seismic wide angle constraints on the crust of the southern UralsJournal of Geophysical Research, Vol. 105, No. 6, June 10, pp. 13755-78.Russia, Urals, KolaGeophysics - seismics
DS201312-0556
2013
Gallart, J.Luciana, B., Schimmel, M., Gallart, J., Morales, J.Studying the 410-km and 660-km discontinuities beneath Spain and Morocco through detection of P-to-s conversions.Geophysical Journal International, Vol. 194, 2, pp. 920-935.Europe, Spain, Africa, MoroccoGeophysics -
DS2002-0706
2002
GallasteguiHeredia, N., Rodiguez Fernandez, L.R., GallasteguiGeological setting of the Argentine frontal Cordillera in the flat slab segment 30 - 31)Journal of South American Earth Sciences, Vol.15,1,Apr.pp.79-99.Chile, AndesSubduction, Slab
DS201412-0412
2014
Gallego, A.Ito, G., Dunn, R.L.A., Wolfe, C.J., Gallego, A., Fu, Y.Seismic anisotropy and shear wave splitting associated with mantle plume-plate interactions.Journal of Geophysical Research, Vol. 119, no. 6, pp. 4923-4937.MantleGeophysics - seismics
DS201112-0173
2011
Gallet, S.Chauvel, C., Garcon, M., Arndt, N.T., Gallet, S., Jahn, B.M.Average Nd hf isotopic compositions and model age of the upper continental crust.Goldschmidt Conference 2011, abstract p.646.Africa, South AfricaBeach placers
DS1998-1505
1998
Gallet, Y.Valet, J.P., Gallet, Y.Paleomagnetism: ancient inclinationNature, Vol. 396, No. 6709, Nov. 26, pp. 315-6.MantleGeophysics - paleomagnetics
DS2000-0309
2000
Gallet, Y.Gallet, Y., Pavlov, V.E., Petrov, P.Y.Late Mesoproterozoic magnetostratigraphic results from Siberia: Paleogeographic implications and magnetics ..Journal of Geophysical Research, Vol.105, No.7, July 10, pp.16481-Russia, SiberiaGeophysics - magnetics
DS2002-1234
2002
Gallet, Y.Pavlov, V.E., Gallet, Y., Petrov, P.Y., Zhuravlev, D.Z., Shatsillo, A.V.The Ui Group and Late Riphean sills in the Uchur Maya area: isotopic andGeotectonics, Vol. 36,4,pp. 278-92.GondwanaGeochronology
DS201412-0522
2014
Gallet, Y.Livermore, P.W., Fournier, A., Gallet, Y.Core-flow constraints on extreme archeomagnetic intensity changes.Earth and Planetary Science Letters, Vol. 387, pp. 145-156.MantleGeophysics - magnetics
DS1989-0367
1989
Galley, A.Dostal, J., Jackson, G.D., Galley, A.Geochemistry of Neohelikian Nauyat plateau basalts, Borden rift basin, northwestern Baffin Island.Canadian Journal of Earth Sciences, Vol. 26, pp. 2214-23.Northwest Territories, Baffin IslandBasalts
DS1997-0041
1997
Galli, A.Armstrong, M., Galli, A.Option pricing: a new approach to valuing mining projectsThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 90, No. 1009, April pp. 37-44GlobalEconomics, geostatistics, valuation, discoveries, Option pricing, evaluation
DS201904-0738
2019
Galli, A.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.
DS1990-0510
1990
Galli, G.Galli, G., Martin, R.M., Car, R., Parrinello, M.Melting of diamond at high pressureScience, Vol. 250, December 14, pp. 1547-1549GlobalDiamond synthesis, Thermal conductivity
DS1991-0529
1991
Galli, G.Galli, G.Diamond melting and liquid carbonPhys. Scr, Vol. T39, pp. 148=150. #GV573GlobalExperimental petrology, Diamond melting
DS1991-0530
1991
Gallo, M.B.M.Gallo, M.B.M.The Romaria diamond bearing Cretaceous conglomerateFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 37-44BrazilConglomerate, Romaria
DS1900-0059
1901
Gallois, L.Gallois, L.La Geologie du Transvaal D'apres MolengraaffAnnual GEOL. PARIS, Vol. 10, PP. 450-453.Africa, South AfricaGeology
DS200812-0805
2008
Galloway, M.Nowicki, T., Helman, C., Gurney, J., Van Coller, B., Galloway, M., Smith, C., Mukodzani, B.Optimizing kimberlite evaluation programs by integrating geological, mineralogical and geophysical data.GSSA-SEG Meeting Held July, Johannesburg, 19 Power point slidesTechnologyEvaluation
DS200812-0806
2008
Galloway, M.Nowicki, T., Hetman, C.J., Gurney, J., Van Collar, B., Galloway, M., Mukodzani, B.Optimizing kimberlite evaluation programs by integrating geological, mineralogical and geophysical data.Northwest Territories Geoscience Office, p. 46-47. abstractTechnologyBrief overview - evaluation
DS200912-0240
2009
Galloway, M.Galloway, M., Nowicki, T., Van Coller, B., Mukodzani, B., Siemens, K., Hetman, C., Webb, K., Gurney, J.Constraining kimberlite geology through integration of geophysical, geological and geochemical methods: a case study of the Mothae kimberlite, northern Lesotho.Lithos, In press - available 47p.Africa, LesothoDeposit - Mothae
DS201806-1224
2018
Galmiche, A.Galmiche, A.Is space our next diamond resource?Gems&Jewellery www.gem-a-com, Spring, pp. 32-35.Technologyasteroids
DS1995-0576
1995
Galoisy, L.Galoisy, L., Calas, G., Brown, G.E.Intracrystalline distribution of nickel in San Carlos olivine: an EXAFS studyAmerican Mineralogist, Vol. 80, No. 9-10, Sept, Oct pp. 1089-1092.ArizonaPeridotite
DS200712-0497
2007
Galoisy, L.Juhin, A., Cabaret, D., Galoisy, L., Hazemann, J-L., Calas, G.First principles investigation of trace element in corporation in minerals: the case of Cr3+ in spinel and pyrope garnet.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.166-167.TechnologyGarnet mineralogy
DS200712-0498
2007
Galoisy, L.Juhin, A., Cabaret, D., Galoisy, L., Hazemann, J-L., Calas, G.First principles investigation of trace element in corporation in minerals: the case of Cr3+ in spinel and pyrope garnet.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.166-167.TechnologyGarnet mineralogy
DS201412-0262
2013
Galoisy, L.Galoisy, L.Garnet: from stone to star.Elements, Vol. 9, 6, Dec. pp. 453-456.TechnologySpectroscopy
DS200712-0344
2006
Galopin de Carvallo, R.Galopin de Carvallo, R.The Braganca diamond discovered?Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.132-3. abstract onlyEurope, PortugalDiamonds notable
DS1984-0233
1984
Galperov, G.Diallo, D., Galperov, G.Tectonique de la Guinee OccidentalePangea., No. 2, JUNE, PP. 20-27.Guinea, West AfricaTectonics
DS1987-0536
1987
Galushkin, E.V.Novgorodova, M.I., Galushkin, E.V., Boyarskaya, R.V., Mokhov, A.V.Accessory minerals of lamproite like rocks of central Asia.(Russian)Izv. Akad. Nauk SSSR, Ser. Geol, No. 4, pp. 15-27RussiaBlank
DS1987-0537
1987
Galuskin, Ye.V.Novgorodova, M.I., Galuskin, Ye.V., Boyzarsdaya, R., Mokhov, A.V.Accessory minerals in lamprophyres of central Asia.(Russian)Izves.Akad. Nauk SSSR, Ser. Geol. (Russian), No. 4, pp. 15-27RussiaLamproite, Petrology
DS1995-0577
1995
Galvao, L.S.Galvao, L.S., Vitorello, F., Paradella, W.R.Spectroradiometric discrimination of laterites with principal components analysis and additive modelingRemote Sensing of Environment, Vol. 53, No. 2, Aug. pp. 70-75GlobalLaterites, Remote sensing
DS201312-0291
2012
Galvez, M.E.Galvez, M.E., Gaillardet, J.Historical constraints on the origins of the carbon cycle concept.Comptes Rendus Geoscience, Vol. 344, pp. 549-567.MantleCarbon cycle
DS201709-1957
2017
Galvez, M.E.Aulbach, S., Woodland, A.B., Vasileyev, P., Galvez, M.E., Viljoen, K.S.Effects of low pressure igneous processes and subduction on Fe3/Fe and redox state of mantle eclogites from Lace ( Kaapvaal craton).Earth and Planetary Science Letters, Vol. 474, pp. 283-295.Africa, South Africadeposit - Lace

Abstract: Reconstructing the redox state of the mantle is critical in discussing the evolution of atmospheric composition through time. Kimberlite-borne mantle eclogite xenoliths, commonly interpreted as representing former oceanic crust, may record the chemical and physical state of Archaean and Proterozoic convecting mantle sources that generated their magmatic protoliths. However, their message is generally obscured by a range of primary (igneous differentiation) and secondary processes (seawater alteration, metamorphism, metasomatism). Here, we report the Fe3+/?Fe ratio and ?18 O in garnet from in a suite of well-characterised mantle eclogite and pyroxenite xenoliths hosted in the Lace kimberlite (Kaapvaal craton), which originated as ca. 3 Ga-old ocean floor. Fe3+/?Fe in garnet (0.01 to 0.063, median 0.02; n = 16) shows a negative correlation with jadeite content in clinopyroxene, suggesting increased partitioning of Fe3+ into clinopyroxene in the presence of monovalent cations with which it can form coupled substitutions. Jadeite-corrected Fe3+/?Fe in garnet shows a broad negative trend with Eu*, consistent with incompatible behaviour of Fe3+ during olivine-plagioclase accumulation in the protoliths. This trend is partially obscured by increasing Fe3+ partitioning into garnet along a conductive cratonic geotherm. In contrast, NMORB-normalised Nd/Yb - a proxy of partial melt loss from subducting oceanic crust (<1) and metasomatism by LREE-enriched liquids (>1) - shows no obvious correlation with Fe3+/?Fe, nor does garnet ?18OVSMOW (5.14 to 6.21‰) point to significant seawater alteration. Median bulk-rock Fe3+/?Fe is roughly estimated at 0.025. This observation agrees with V/Sc systematics, which collectively point to a reduced Archaean convecting mantle source to the igneous protoliths of these eclogites compared to the modern MORB source. Oxygen fugacites (fO2) relative to the fayalite-magnetite-quartz buffer (FMQ) range from ?log ? fO2 = FMQ-1.3 to FMQ-4.6. At those reducing conditions, the solubility of carbon in the fluids released by dehydration is higher than in fluids closer to FMQ. The implication is that Archean processes of C transport and deposition would have differed from those known in modern-style subduction zones, and diamond would have formed from methane-rich fluids. In addition, such reducing material could drive redox melting or freezing upon deep recycling and migration of CH4-bearing fluids into the ambient mantle.
DS201707-1339
2017
Galy, 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.
DS202011-2033
2020
Galy, A.Casola, V., France, L., Galy, A., Bouden, N., Villeneuve, J.No evidence for carbon enrichment in the mantle source of carbonatites in eastern Africa.Geology, Vol. 48, 10, pp. 971976. pdfAfrica, Tanzaniadeposit - Oldoinyo Lengai

Abstract: Carbonatites are unusual, carbon-rich magmas thought to form either by the melting of a carbon-rich mantle source or by low-degree partial melting of a carbon-poor (<80 ppm C) mantle followed by protracted differentiation and/or immiscibility. Carbonate-bearing mantle xenoliths from Oldoinyo Lengai (East African Rift), the only active volcano erupting carbonatites, have provided key support for a C-rich mantle source. Here, we report unique microscale O and C isotopic analyses of those carbonates, which are present as interstitial grains in the silicate host lava, veins in the xenoliths, and pseudo-inclusions in olivine xenoliths. The ?18O values vary little, from 19‰ to 29‰, whereas ?13C values are more variable, ranging from -23‰ to +0.5‰. We show that such carbonate ?18O values result from the low-temperature precipitation of carbonate in equilibrium with meteoric water, rather than under mantle conditions. In this framework, the observed ?13C values can be reproduced by Rayleigh distillation driven by carbonate precipitation and associated degassing. Together with petrological evidence of a physical connection between the three types of carbonates, our isotopic data support the pedogenic formation of carbonates in the studied xenoliths by soil-water percolation and protracted crystallization along xenolith cracks. Our results refute a mechanism of C enrichment in the form of mantle carbonates in the mantle beneath the Natron Lake magmatic province and instead support carbonatite formation by low-degree partial melting of a C-poor mantle and subsequent protracted differentiation of alkaline magmas.
DS202012-2210
2020
Galy, A.Casola, V., France, L., Galy, A., Bouden, N., Villeneuve, J.No evidence for carbon enrichment in the mantle source of carbonatites in eastern Africa.Geology, Vol. 48, 10, 5p. PdfAfrica, Tanzaniacarbonatites

Abstract: Carbonatites are unusual, carbon-rich magmas thought to form either by the melting of a carbon-rich mantle source or by low-degree partial melting of a carbon-poor (<80 ppm C) mantle followed by protracted differentiation and/or immiscibility. Carbonate-bearing mantle xenoliths from Oldoinyo Lengai (East African Rift), the only active volcano erupting carbonatites, have provided key support for a C-rich mantle source. Here, we report unique microscale O and C isotopic analyses of those carbonates, which are present as interstitial grains in the silicate host lava, veins in the xenoliths, and pseudo-inclusions in olivine xenoliths. The ?18O values vary little, from 19‰ to 29, whereas ?13C values are more variable, ranging from -23‰ to +0.5‰. We show that such carbonate ?18O values result from the low-temperature precipitation of carbonate in equilibrium with meteoric water, rather than under mantle conditions. In this framework, the observed ?13C values can be reproduced by Rayleigh distillation driven by carbonate precipitation and associated degassing. Together with petrological evidence of a physical connection between the three types of carbonates, our isotopic data support the pedogenic formation of carbonates in the studied xenoliths by soil-water percolation and protracted crystallization along xenolith cracks. Our results refute a mechanism of C enrichment in the form of mantle carbonates in the mantle beneath the Natron Lake magmatic province and instead support carbonatite formation by low-degree partial melting of a C-poor mantle and subsequent protracted differentiation of alkaline magmas.
DS1988-0360
1988
Galymova, A.Klyuev, Yu.A., Galymova, A., Korneeva, I.I., Naletov, A.M., NepshaPhotoluminescence tomography as a method to image point defect distributions in crystals- nitrogen-vacancy pairs in syntheticdiamonds*technical noteNov. Obl. Primeniya Tekn.Almazov, (Russian), pp. 24-30RussiaLuminescence
DS202201-0014
2021
Galzyrin, G.Galzyrin, G., Mukherjee, D.Synthesis and compression study of orthorhombic Fe7 (C,Si)3: a possoible constituent of the Earth's core.International Journal of High Pressure Research, Vol. 41, 3, pp. 290-305.Mantlemineralogy

Abstract: The orthorhombic phase of Si-doped Fe carbide is synthesized at high-pressures and temperatures using laser-heated diamond anvil cell (LHDAC), followed by its characterization using X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Raman spectroscopy. Room-temperature high-pressure XRD measurements are carried out up to about 104 GPa for the determination of the equation of state parameters. No evidence of structural transition is observed. Pressure evolution of isothermal bulk modulus shows elastic stiffening around 28 GPa followed by softening around 78 GPa, which are possibly related to magnetic transitions driven by pressure-induced anisotropic strain in the unit cell. Extrapolation of the density profile of our study to the inner core conditions agrees very well with PREM data with an uncertainty of about 3-4%. Our estimated bulk modulus value at core pressures seems to be 8-9% less than that of PREM data and is best matched in comparison to other reported values.
DS202107-1108
2021
Gama, I.Krueger, H.E., Gama, I., Fischer, K.M.Global patterns in cratonic mid-lithospheric discontinuities from Sp receiver functions. ( shield)Geochemistry, Geophysics, Geosytems, 19p. PdfCanada, Ontariogeophysics - seismics

Abstract: We investigate the structure of the continental lithosphere (tectonic plate) in regions that have had negligible tectonic activity, such as mountain building, for the past 500 million years. The internal structure of the lithosphere in these regions can be indicative of the ancient processes that first formed continents. Due to challenges in methodology, layering within the upper 150 km of the continental lithosphere is poorly understood. We carefully process earthquake data to avoid problems that previous studies encountered. We observe layering in 50% of the ancient continental regions. Most of this layering can be explained by the presence of minerals that have lower seismic velocities than the surrounding rock because they have been altered by fluids during the formation of the continent. In regions closer to more recent tectonic activity, some layering has stronger seismic velocity decreases, indicating the effects of more recent alteration. We also find that layering is more prevalent in the continental regions that last experienced tectonic activity no later than 1.6 billion years ago. This corresponds with a global transition in the depth to which the subducting lithosphere carries fluids into the mantle, indicating that subduction has a key role in generating layering in the ancient continental lithosphere.
DS1986-0693
1986
Gamarik, M.Y.Rybalko, S.I., Gamarik, M.Y., Rybalkova, E.A., Nagaleva, N.B.The finding of feldspar in diamond.(Russian)Mineral. Zhurnal, (Russian), Vol.8, No. 6, pp. 78-79RussiaBlank
DS1987-0610
1987
Gamarik, M.Ya.Ribalko, S.I., Metalidi, S.V., Gamarik, M.Ya., et al.Typomorphism of diamond crystals from ancient coarse grained rocks of the northwestern Ukrainian shield.(Russian)Akad. Nauk UKR.RSR Institute Geokhim. I Fiz. Mineral.(Russian), Vol. 1987, No. 6, pp. 27-29RussiaBlank
DS1987-0632
1987
Gamarnik, M. Ya.Rybalko, S.I., Metalidi, S.V., Gamarnik, M. Ya., et al.Typomorphism of diamond crystals from ancient coarse detritalrocks In the northwestern part of the Ukrainian shield.(Russian)Doklady Academy of Sciences Nauk. UKR. Miner., (Russian), No. 6, pp. 27-30RussiaBlank
DS1988-0588
1988
Gamarnik, M.Ya.Rybalko, S.I., Galii, G.A., Gamarnik, M.Ya., et al.Electron optical studies of zircon from kimberlites.(Russian)Ontogeniya Mineralov I Teknol Mineral Kiev.(Russian), pp. 160-165RussiaMircoprobe, Zircon
DS1985-0213
1985
Gamble, J.A.Gamble, J.A.The Mucurdo Volcanics of the Ross Dependency, East AntarcticConference Report of The Proceedings of The Meeting of The V, 1P. ABSTRACT.GlobalBasanite, Erebus
DS1988-0235
1988
Gamble, J.A.Gamble, J.A., McGibbon, F., Kyle, P.R., Menzies, M.A., Kirsch, I.Metasomatised xenoliths from Foster Crater Antarctica:implications for lithospheric structure and processes beneath the Transantarctic Mountain FrontJournal of Petrology, Special Volume 1988- Oceanic and Continental, pp. 109-138AntarcticaFoster Crater
DS1991-1100
1991
Gamble, J.A.McCulloch, M.T., Gamble, J.A.Geochemical and geodynamical constraints on subduction zone magmatismEarth and Planetary Science Letters, Vol. 102, No. 3/4, March pp. 358-374GlobalGeochemistry, Mantle
DS1999-0235
1999
Gamble, J.A.Gamble, J.A., Wysoczanski, R.J., Meighan, I.G.Constraints on the age of the British Tertiary Volcanic Province from ion microprobe uranium-lead (U-Pb) SHRIMP ages...Journal of Geological Society of London, Vol. 156, No. 2, Mar. pp. 291-300.IrelandGeochronology - acid igneous rocks
DS2003-0546
2003
Gamble, J.A.Handler, M.R., Wysoczanski, R.J., Gamble, J.A.Proterozoic lithosphere in Marie Byrd Land, West Antarctica: Re Os systematics ofChemical Geology, Vol. 196, 1-4, pp. 131-45.AntarcticaGeochronology, Xenoliths
DS200412-0779
2003
Gamble, J.A.Handler, M.R., Wysoczanski, R.J., Gamble, J.A.Proterozoic lithosphere in Marie Byrd Land, West Antarctica: Re Os systematics of spinel peridotite xenoliths.Chemical Geology, Vol. 196, 1-4, pp. 131-45.AntarcticaGeochronology Xenoliths
DS202003-0335
2020
Gamel El Dien, H.Doucet, L.S., Li, Z-X., Ernst, R.E., Kirscher, U., Gamel El Dien, H., Mitchell, R.N.Coupled supercontinent-mantle plume events evidence by oceanic plume record.Geology, Vol. 48, pp. 159-163.Mantle, Africageodynamics

Abstract: The most dominant features in the present-day lower mantle are the two antipodal African and Pacific large low-shear-velocity provinces (LLSVPs). How and when these two structures formed, and whether they are fixed and long lived through Earth history or dynamic and linked to the supercontinent cycles, remain first-order geodynamic questions. Hotspots and large igneous provinces (LIPs) are mostly generated above LLSVPs, and it is widely accepted that the African LLSVP existed by at least ca. 200 Ma beneath the supercontinent Pangea. Whereas the continental LIP record has been used to decipher the spatial and temporal variations of plume activity under the continents, plume records of the oceanic realm before ca. 170 Ma are mostly missing due to oceanic subduction. Here, we present the first compilation of an Oceanic Large Igneous Provinces database (O-LIPdb), which represents the preserved oceanic LIP and oceanic island basalt occurrences preserved in ophiolites. Using this database, we are able to reconstruct and compare the record of mantle plume activity in both the continental and oceanic realms for the past 2 b.y., spanning three supercontinent cycles. Time-series analysis reveals hints of similar cyclicity of the plume activity in the continent and oceanic realms, both exhibiting a periodicity of ?500 m.y. that is comparable to the supercontinent cycle, albeit with a slight phase delay. Our results argue for dynamic LLSVPs where the supercontinent cycle and global subduction geometry control the formation and locations of the plumes.
DS202008-1384
2020
Gamel El Dien, H.Doucet, L.S., Li, Z-X., Gamel El Dien, H., Pourteau, A., Murphy, B., Collins, W.J., Mattielli, N., Olierook, H.K.H., Spencer, C.J., Mitchell, R.N.Distinct formation history for deep mantle domains reflected in geochemical differences.Nature Geoscience, Vol. 13, pp. 511-515. pdfMantlegeochemistry

Abstract: The Earth’s mantle is currently divided into the African and Pacific domains, separated by the circum-Pacific subduction girdle, and each domain features a large low shear-wave velocity province (LLSVP) in the lower mantle. However, it remains controversial as to whether the LLSVPs have been stationary through time or dynamic, changing in response to changes in global subduction geometry. Here we compile radiogenic isotope data on plume-induced basalts from ocean islands and oceanic plateaus above the two LLSVPs that show distinct lead, neodymium and strontium isotopic compositions for the two mantle domains. The African domain shows enrichment by subducted continental material during the assembly and breakup of the supercontinent Pangaea, whereas no such feature is found in the Pacific domain. This deep-mantle geochemical dichotomy reflects the different evolutionary histories of the two domains during the Rodinia and Pangaea supercontinent cycles and thus supports a dynamic relationship between plate tectonics and deep-mantle structures.
DS202009-1625
2020
GamelEl Dien, H.Doucet, L.S., Li, Z-X., GamelEl Dien, H., Pourteau, A., Murphy, J.B., Collins, W.J., Mattielli, N., Olierook, H.K.H., Spencer, C.J., Mitchell, R.N.Distinct formation history for deep mantle domains reflected in geochemical differences.Nature Geoscience, Vol. 13, July pp. 511-515. pdfMantlegeochemistry

Abstract: The Earth’s mantle is currently divided into the African and Pacific domains, separated by the circum-Pacific subduction girdle, and each domain features a large low shear-wave velocity province (LLSVP) in the lower mantle. However, it remains controversial as to whether the LLSVPs have been stationary through time or dynamic, changing in response to changes in global subduction geometry. Here we compile radiogenic isotope data on plume-induced basalts from ocean islands and oceanic plateaus above the two LLSVPs that show distinct lead, neodymium and strontium isotopic compositions for the two mantle domains. The African domain shows enrichment by subducted continental material during the assembly and breakup of the supercontinent Pangaea, whereas no such feature is found in the Pacific domain. This deep-mantle geochemical dichotomy reflects the different evolutionary histories of the two domains during the Rodinia and Pangaea supercontinent cycles and thus supports a dynamic relationship between plate tectonics and deep-mantle structures.
DS201012-0128
2010
Gamero, E.J.Courtier, A.M., Gaherty, J.B., Revenaugh, J., Bostock, M.G., Gamero, E.J.Seismic anisotropy associated with continental lithosphere accretion beneath the CANOE array, northwestern Canada.Geology, Vol. 38, 10, pp. 887-890.Canada, Alberta, Northwest TerritoriesGeophysics - seismics
DS201112-0571
2011
Gamero, E.J.Lay, T., Gamero, E.J.Deep mantle seismic modeling and imaging.Annual Review of Earth and Planetary Sciences, Vol. 39, pp. 91-123.MantleGeophysics - seismics
DS1993-0479
1993
Gamey, J.Gamey, J.A statistical analysis of airborne geophysical targets in the search fordiamonds. #1Northwest Territories Exploration Overview for 1993, November pp. 30-31.Northwest TerritoriesGeophysics, Magnetics
DS1994-0567
1994
Gamey, T.J.Gamey, T.J.A statistical analysis of airborne geophysical targets in the search fordiamonds. #2The Professional Association of Geologists and Geophysicists of Qu?bec (APGGQ) 1994, held Val'D'Or Aprl 13-15., 1p. abstractNorthwest Territories, QuebecGeophysics
DS2003-1039
2003
Gammon, J.B.Owsiacki, I., Gammon, J.B.Reaching out - MDMN's "3 Offers" to Ontario's Far North First NationsOntario Geological Survey Open File, No. 6120, pp. I 1-4.OntarioLegal - First Nations
DS200412-1487
2003
Gammon, J.B.Owsiacki, I., Gammon, J.B.Reaching out - MDMN's '3 Offers' to Ontario's Far North First Nations.Ontario Geological Survey Open File, No. 6120, pp. I 1-4.Canada, OntarioLegal - First Nations
DS1991-0601
1991
Gamond, J.F.Gratier, J.P., Gamond, J.F.Transition between seismic and aseismic deformation in the upper crustDeformation Mechanisms, Rheology and Tectonics, editors Knipe, R.J., No. 54, pp. 461-473GlobalTectonics, Geophysics -seismics
DS1960-1001
1968
Gamyanina, V.V.Nekrasova, R.A., Gamyanina, V.V.The Composition of Rare Earth Elements in Kimberlite MineralDoklady Academy of Science USSR, Earth Science Section., Vol. 182, PP. 195-198.RussiaBlank
DS1970-0156
1970
Gamyanina, V.V.Nekrasova, R.A., Gamyanina, V.V., Rozhdestvenskaya, I.V.The Zro2lhfo2 Ratio in Zircons from Kimberlites and \ Alluvial Sediments.Geochemistry International, Vol. 7, No. 3, PP. 536-542.RussiaBlank
DS1970-0157
1970
Gamyanina, V.V.Nikisov, K.N., Gamyanina, V.V.Trace Elements in Perovskite from Intrusive KimberlitesIn: Geology, Petrography And Mineralogy of The Northeast Par, AKAD. NAUK SSSR, PP. 281-287.RussiaBlank
DS202004-0502
2020
Gan, C.Cawood, P.A., Wang, W., Zhao, T., Xu, Y., Mulder, J.A., Pisarevsky, S.A., Zhang, L., Gan, C., He, H., Liu, H., Qi, L., Wang, Y., Yao, J., Zhao, G., Zhou, M-F., Zi, J-W.Deconstructing south China and consequences for reconstructing Nuna and Rodinia.Earth-Science Reviews, in press available, 70p. PdfChinatectonics

Abstract: Contrasting models for internal and external locations of South China within the Nuna and Rodinia supercontinents can be resolved when the current lithotectonic associations of Mesoproterozoic and older rocks units that constitute the craton are redefined into four lithotectonic domains: Kongling, Kunming-Hainan, Wuyi, and Coastal. The Kongling and Kunming-Hainan domains are characterized by isolated Archean to early Paleoproterozoic rock units and events and crop out in northern and southern South China, respectively. The Kunming-Hainan Domain is preserved in three spatially separated regions at Kunming (southwestern South China), along the Ailaoshan shear zone, and within Hainan Island. Both domains were affected by late Paleoproterozoic tectonothermal events, indicating their likely juxtaposition by this time to form the proto-Yangtze Block. Late Paleoproterozoic and Mesoproterozoic sedimentary and igneous rock units developed on the proto-Yangtze Block, especially in its southern portions, and help link the rock units that formed along the shear zone at Ailaoshan and on Hainan Island into a single, spatially unified unit prior to Paleozoic to Cenozoic structural disaggregation and translation. The Wuyi Domain consists of late Paleoproterozoic rock units within a NE-SW trending, fault-bounded block in eastern South China. The Coastal Domain lies east of the Wuyi domain and is inferred to constitute a structurally separate block. Basement to the domain is not exposed, but zircon Hf model ages from Mesozoic granites suggest Mesoproterozoic basement at depth. The Archean to Paleoproterozoic tectonothermal record of the Kongling and Kunming-Hainan domains corresponds closely with that of NW Laurentia, suggesting all were linked, probably in association with assembly and subsequent partial fragmentation of the Nuna supercontinent. Furthermore, the age and character of Mesoproterozoic magmatism and detrital zircon signature of sedimentary rocks in the proto-Yangtze Block matches well with western Laurentia and eastern Australia-Antarctica. In particular, the detrital zircon signature of late Paleoproterozoic to early Mesoproterozoic sedimentary units in the block (e.g. Dongchuan Group) share a similar age spectrum with the Wernecke Supergroup of northwest Laurentia. This, together with similarities in the type and age of Fe-Cu mineralization in the domain with that in eastern Australia-Antarctica, especially northeast Australia, suggests a location adjacent to northwest Laurentia, southern Siberia, and northeast Australia within the Nuna supercontinent. The timing and character of late Paleoproterozoic magmatic activity in the Wuyi domain along with age of detrital zircons in associated sedimentary rocks matches the record of northern India. During rifting between Australia-Antarctica and Laurentia in the late Mesoproterozoic, the proto-Yangtze Block remained linked to northeast Australia. During accretionary orogenesis in the early Neoproterozoic, the proto-Yangtze Block assembled with the Wuyi Domain along the northern margin of India. The Coastal domain likely accreted at this time forming the South China Craton. Displacement of the Hainan and Ailaoshan assemblages from southwest of the Kunming assemblage likely occurred in the Cenozoic with the activation of the Ailaoshan-Red River fault system but could have begun in the early to mid-Paleozoic based on evidence for tectonothermal events in the Hainan assemblage.
DS2001-0442
2001
Gan, J.Han, B-F., Zheng, Y., Gan, J., Chang, Z.The Louzidian normal fault near Chifeng: master fault of a quasi metamorphic core complex.International Geology Review, Vol. 43, pp. 254-64.GlobalTectonics, Qinling Dabie Orogenic belt, ultra high pressure (UHP)
DS202101-0027
2020
Ganade, C.E.Pessano, P.C., Ganade, C.E., Tupinamba, M., Teixeira, W.Updated map of the mafic dike swarms of Brazil based on airborne geophysical data.Journal of South American Earth Sciences, in press available, 16p. PdfSouth America, Brazilgeophysics

Abstract: Identification of mafic dike swarms and LIPs (Large Igneous Provinces) are of vital importance in geologic history because they provide information on geodynamics, mantle geochemistry, and paleomagnetism. These data provide key information for paleogeographic reconstructions with the aid of barcode matches and precise radiometric ages. Considering such issues, the Brazilian Precambrian shield can be used as a case for refining the cartography of the relevant intraplate activity (e.g., dikes, sills, flood basalts) in space and time. This work presents an updated map of Brazilian mafic dike swarms produced from airborne geophysical maps (Series 1000 - Geological Survey of Brazil). Linear and strong anomalies found on aeromagnetic maps using First Vertical Derivative of the Magnetic Field and Amplitude of the Analytic Signal were mapped on a GIS platform. The obtained data were compared to ternary radiometric maps and geological maps in order to exclude those that do not correspond to mafic dikes. The remaining structures - those believed to represent mafic dikes - were classified based on data compiled from the literature. The updated map exhibits more than 5000 elements, including dikes and magmatic suites, in which about 75% were geologically identified and divided into 60 dike swarms and 10 igneous suites and/or units. The dikes were grouped into sixteen extensional episodes from the Archean to the Cenozoic, although some are related to extension/transtension domains within regional compressive zones akin to orogenic settings. The most frequent records refer to the Proterozoic, representing intraplate episodes, some of them consistent with LIPs. The dataset also includes a large record of the Mesozoic age, which corresponds to major LIP events related to the opening of the Atlantic Ocean and the fragmentation of Gondwana.
DS202103-0379
2021
Ganbat, A.Ganbat, A., Tsujimori, T., Boniface, N., Pastor-Galan, D., Aoki, S., Aoki, K.Crustal evolution of Paleoproterozoic Ubendian Belt ( SW Tanzania) western margin: a central African shield amalgamation take.Gondwana Research, Vol. 91, pp. 286-306. pdfAfrica, Tanzaniamagmatism

Abstract: The Ubendian Belt between the Archean Tanzania Craton and the Bangweulu Block, represents a Paleoproterozoic orogeny of these two constituents of the Congo Craton assembled at ~1.8?Ga, forming the Central African Shield, during the Columbia Supercontinent cycle and consolidated during the Gondwana assembly. Metagranitoids from the Southern and Northern Ufipa Terranes (Western Ubendian Corridor) and those of the Bangweulu Block are compositionally similar and are contemporaneous. The protolith of the Ufipa Terrane is originated from the collided crustal rocks of the Bangweulu Block. New LA-ICPMS zircon U-Pb age of metagranitoids and granoporphyries confirmed magmatic events from 1.89 to 1.85?Ga. The metagranitoids of the Western Ubendian Corridor and that of the Bangweulu Block cannot be distinguished by their trace element characteristics and ages. Geochemically, they belong to high-K calc-alkaline to tholeiite series. The 1.89-1.85?Ga metagranitoids and granoporphyries are characterized by evolved nature, which are common for slab-failure derived magmas. Such geochemical features and the presence of ~2.0?Ga eclogites suggest an Orosirian oceanic subduction and subsequent slab break-off. Melt derived from the mafic upper portion of torn slab led to the partial melting of crust which formed high-K and calc-alkaline, I- and S-type magmatism in the Bangweulu Block and the Ufipa Terrane. Zircons from two metagranites from the Northern Ufipa Terrane show Neoproterozoic (Ediacaran) overprints at ~570?Ma, suggesting the Bangweulu Block collided with the continental margin of the Tanzania Craton. However, we found non-annealed Orosirian apatites in metagranitoids from the Southern Ufipa Terrane and the Kate-Ufipa Complex, implying that areal heterogeneity of the Pan-African tectonothermal overprint in the Ufipa Terrane. All evidences suggest that the Bangweulu Block and the Ubendian Belt participated in the amalgamation of the Central African Shield as separated continents surrounded by oceanic crusts during the Paleoproterozoic Eburnean and the Neoproterozoic Pan-African orogenies.
DS1988-0613
1988
GandhiScharer, U., Krogh, T.E., Wardle, Ryan, Gandhiuranium-lead (U-Pb) ages of early to middle Proterozoic volcanism and metamorphism in the Makkovik Orogen, Labrador.Canadian Journal of Earth Sciences, Vol. 25, pp. 1098-1107.LabradorGeochronology
DS2001-0352
2001
Gandhi, S.S.Gandhi, S.S., Mortensen, J.K., Prasad, N., Van BreemenMagmatic evolution of the southern Great Bear continental arc, northwestern Canadian shield....Canadian Journal of Earth Sciences, Vol. 38, No. 5, May, pp. 767-85.Northwest TerritoriesGeochronology - Slave Craton
DS200612-0422
2005
Gandhi, S.S.Gandhi, S.S., Van Breemen, O.SHRIMP U Pb geochronology of detrital zircons from the Treasure Lake Group - new evidence for Paleoproterozoic collisional tectonics in the southern Hottah terrane.Canadian Journal of Earth Sciences, Vol. 42, 5, pp. 833-845.Canada, Northwest TerritoriesGeochronology - not specific to diamonds
DS2002-0466
2002
Gandhok, G.Fodor, R.V., Sial, A.N., Gandhok, G.Petrology of spinel peridotite xenoliths from northeastern Brasil: lithosphere with a high geothermal gradient imparted by Fernando de Nornha plume.Journal of South American Earth Sciences, Vol.15,2,June pp. 183-98.BrazilGeothermometry, Hot spots
DS2002-0467
2002
Gandhok, G.Fodor, R.V., Sial, A.N., Gandhok, G.Petrology of spinel peridotite xenoliths from northeastern Brasil: lithosphere with a high geothermal gradient imparted by Fernando de Noronha plume.Journal of South American Earth Sciences, Vol. 15, No. 2, pp. 199-214.BrazilTectonics, Xenoliths
DS2002-0468
2002
Gandhok, G.Fodor, R.V., Sial, A.N., Gandhok, G.Petrology of spinel peridotite xenoliths from northeastern Brasil: lithosphere with a high geothermal gradient imparted by Fernando de Noronha plume.Journal of South American Earth Sciences, Vol.15,2,June pp. 199-214.Brazil, northeastMagmatism, hot spots, Geothermometry
DS1991-0494
1991
Gandhok, G.R.Fodor, R.V., Gandhok, G.R., Sial, A.N.Vertical sampling of mantle beneath northeastern Brasil as represented by ultramafic xenoliths and megacrysis in Tertiary basaltsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 101-102BrazilXenoliths, Mantle peridotite
DS201112-0734
2010
Gandini, A.L.Newman, J.A., Teixeira Carvalho de Newman, D., Gandini, A.L., Souza Gomes, N., Krambrock, K.W.H., Pimenta, M.A.Caracterizacao mineralogica dos diamantes policristalinos (carbonados) da regiao de Santa Elena de Uairen, estado Bolivar, Venezuela.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 46-47.South America, VenezuelaCarbonado
DS201112-0735
2010
Gandini, A.L.Newman, J.A., Teixeira Carvallo de Newman, D.,Gandini, A.L.Classificacao tipologica do diamante da regiao de Santa Elena de Uairen, estado Bolivar, Venezuela, baseada na espectroscopia de absorcao no infravermelho.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 41-42.South America, VenezuelaDiamond morphology
DS200512-0310
2004
Ganero, E.J.Ganero, E.J., Maupin, V., Lay, T., Founch, M.J.Variable azimuthal anisotropy in Earth's lowermost mantle.Science, No. 5694, Oct. 8, p. 259-260.MantleGeophysics
DS202010-1844
2020
Ganesan, K.Genish, H., Ganesan, K., Stacey, A., Prawer, S., Rosenbluh, M.Effect of radiation damage on the quantum optical properties of nitrogen vacancies in diamond.Diamond & Related Materials, Vol. 109, 108049, 6p. PdfMantlenitrogen

Abstract: Single crystal diamond (<5?ppm nitrogen) containing native NV centers with coherence time of 150??s was irradiated with 2?MeV alpha particles, with doses ranging from 1012 ion/cm2 to 1015 ion/cm2. The effect of ion damage on the coherence time of NV centers was studied using optically detected magnetic resonance and supplemented by fluorescence and Raman microscopy. A cross-sectional geometry was employed so that the NV coherence time could be measured as a function of increasing defect concentration along the ion track. Surprisingly, although the ODMR contrast was found to decrease with increasing ion induced vacancy concentration, the measured decoherence time remained undiminished at 150us despite the estimated vacancy concentration reaching a value of 40?ppm at the end of range. These results suggest that ion induced damage in the form of an increase in vacancy concentration does not necessarily result in a significant increase in the density of the background spin bath.
DS200412-0603
2004
Ganesha Raj, K.Ganesha Raj, K.Major lineaments of Karnataka State and their relation to seismicity: a remote sensing based analysis.Journal Geological Society of India, Vol. 63, 4, pp. 430-439.India, KarnatakaStructure, 43 major lineaments
DS201710-2227
2017
Ganey, G.Q.Ganey, G.Q., Loso, M.G., Burgess, A.B., Dial, R.J.The role of microbes in snowmelt and radiative forcing on an an Alaskan icefield. Red algaeNature Geoscience, Sept. 18, onlineUnited States, Alaskageomorphology

Abstract: A lack of liquid water limits life on glaciers worldwide but specialized microbes still colonize these environments. These microbes reduce surface albedo, which, in turn, could lead to warming and enhanced glacier melt. Here we present results from a replicated, controlled field experiment to quantify the impact of microbes on snowmelt in red-snow communities. Addition of nitrogen-phosphorous-potassium fertilizer increased alga cell counts nearly fourfold, to levels similar to nitrogen-phosphorus-enriched lakes; water alone increased counts by half. The manipulated alga abundance explained a third of the observed variability in snowmelt. Using a normalized-difference spectral index we estimated alga abundance from satellite imagery and calculated microbial contribution to snowmelt on an icefield of 1,900?km2. The red-snow area extended over about 700?km2, and in this area we determined that microbial communities were responsible for 17% of the total snowmelt there. Our results support hypotheses that snow-dwelling microbes increase glacier melt directly in a bio-geophysical feedback by lowering albedo and indirectly by exposing low-albedo glacier ice. Radiative forcing due to perennial populations of microbes may match that of non-living particulates at high latitudes. Their contribution to climate warming is likely to grow with increased melt and nutrient input.
DS200412-1320
2004
Gang, L.Mingjie, Z., Zianbin, W., Gang, L., Tongwei, Z., Wenrui, B.Compositions of upper mantle fluids beneath eastern China: implications for mantle evolution.Acta Geologica Sinica, Vol. 78, 1, pp. 125-130.ChinaGeochemistry
DS1994-0568
1994
Gang ChaiGang ChaiChina's mineral endowmentAsian Mining Opportunities Symposium Aug. 3, 4th, 23pChinaEconomics
DS1994-0569
1994
Gang ChaiGang ChaiChina's mineral endowmentAsian Mining Opportunities Symposium Aug. 3, 4., 23p.ChinaMining, Economics -mentions diamonds
DS1990-0511
1990
Gang LuGang Lu, Marshak, S., Kent, D.V.Characteristics of magnetic carriers responsible for Late Paleozoic remagnitization in carbonate strat a of the Mid-continent, USAEarth and Planetary Science Letters, Vol. 99, pp. 351-361MidcontinentGeophysics -remagnetization, Tectonics
DS2003-1189
2003
Ganga, J.Rotman, A., Ganga, J., Nosiko, S.Pipe Catoca, an example of the weakly eroded kimberlites from north east Angola8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractAngolaKimberlite geology and economics, Deposit - Catoca
DS200512-0914
2004
Ganga, J.Rotman, A.Y., Ganga, J., Nosyko, S.F., Shimupi, J., Zintchouk, N.N., Somov, S.V.Kimberlites of Angola: structural tectonic position and geology.Deep seated magmatism, its sources and their relation to plume processes., pp. 178-193.Africa, AngolaTectonics
DS1960-1106
1969
Gangadharam, E.V.Gangadharam, E.V., Aswathanarayana, V.Trace Element Content of Kimberlites of South IndiaEos, Vol. 50, P. 341. (abstract.).IndiaMineralogy
DS1970-0293
1971
Gangadharam, E.V.Gangadharam, E.V., Aswathanarayana, V.Th/u Ratio As an Aid in Prospecting for Diamonds in the Kimberlitic Rocks of India.Current Science., Vol. 24, DECEMBER, PP. 663-664.IndiaProspecting
DS1991-0531
1991
Gangi, A.F.Gangi, A.F.World rift systems. Special issueTectonophysics, Vol. 197, No. 2-4, pp. 99-390GlobalTectonics, World rift systems
DS1980-0135
1980
Gangopadhyay, S.Gangopadhyay, S.Bibliography on Dyke and Pipe Rocks of IndiaIndian Minerals, Vol. 34, No. 3, , PP. 43-52.IndiaBibliography
DS1996-0759
1996
Gangui, A.H.Kley, J., Gangui, A.H., Kruger, D.Basement involved blind thrusting in the eastern Cordillera Oriental:evidence from cross sect. balanceTectonophysics, Vol. 259, No. 1-3, June 30, pp. 171-184BoliviaGeophysics -magnetotellurics, gravity, Tectonics
DS2001-1057
2001
Ganguly, A.Shanker, R., Nag, S., Ganguly, A., Absar, Rawat, SinghAre Majhgawan Hinota pipe rocks truly group I kimberlite?Indian Acad. Sciences Earth and Plan., Vol. 110, No. 1, pp. 63-76.IndiaKimberlite - classification, Deposit - Majhgawan
DS200412-1793
2003
Ganguly, A.Shanker, R., Nag, S., Ganguly, A., Rawat, B.P.Chemistry of common and minor minerals in orangeite ( group II kimberlite) of Majhgawan, Panna District, Madhya Pradesh, India.Indian Journal of Geology, Vol. 73, pp. 207-220.India, Madhya PradeshGeochemistry - orangeite
DS1987-0234
1987
Ganguly, J.Ganguly, J., Bhattacharya, P.K.Xenoliths in Proterozoic kimberlites from southern India:petrology and geophysical implicationsin: Nixon, P.H. ed. Mantle xenoliths, J. Wiley, pp. 249-266IndiaGeophysics, Analyses p. 251-2 ultrab
DS1992-0511
1992
Ganguly, J.Ganguly, J.Comments on evaluation of thermobarometers for garnet peridotites. Response to comments by Finnerty and BoydGeochimica et Cosmochimica Acta, Vol. 56, No. 2, February pp. 841-860GlobalGeothermometry, Garnet peridotites
DS200512-0311
2005
Ganguly, J.Ganguly, J.Adiabatic decompression and melting of mantle rocks: an irreversible thermodynamic analysis.Geophysical Research Letters, Vol. 32, 6, March 28, L06312MantleMelting
DS200612-0423
2006
Ganguly, J.Ganguly, J., Sacena, S.K., Freed, A.M.Density variation in subducting slabs and surrounding upper mantle: understanding stagnation vs penetration of the slabs at 670 km discontinuity.International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p.102.MantleSubduction
DS200912-0241
2009
Ganguly, J.Ganguly, J., Freed, A.M., Saxena, S.K.Density profiles of oceanic slabs and surrounding mantle: integrated thermodynamic and thermal modeling, and implications for the fate of slabs at the 660 kmPhysics of the Earth and Planetary Interiors, Vol. 172, 3-4, pp. 257-267.MantleGeothermometry
DS200912-0764
2009
Ganguly, J.Tirose, M., Ganguly, J., Morgan, J.P.Modeled petrological geodynamics in the Earth's mantle.Geochemistry, Geophysics, Geosystems: G3, Vol. 10, Q04012.MantleThermometry
DS1994-0570
1994
Ganguly, P.Ganguly, P., et al.Evidence for superconductivity onset at 40 K in a carbon based systemCurrent Science, Vol. 67, No. 3, August 10, pp. 202-204.MantleCarbon
DS201511-1874
2015
Ganguly, S.Saha, A., Manikyamba, C., Santosh, M., Ganguly, S., Khelen, A.C.Platinum Group Elements ( PGE) geochemistry of komatiites and boninites from Dharwar Craton, India: implications for mantle melting processes.Journal of Asian Earth Sciences, Vol. 105, pp. 300-319.IndiaBoninites

Abstract: High MgO volcanic rocks having elevated concentrations of Ni and Cr are potential hosts for platinum group elements (PGE) owing to their primitive mantle origin and eruption at high temperatures. Though their higher PGE abundance is economically significant in mineral exploration studies, their lower concentrations are also valuable geochemical tools to evaluate petrogenetic processes. In this paper an attempt has been made to evaluate the PGE geochemistry of high MgO volcanic rocks from two greenstone belts of western and eastern Dharwar Craton and to discuss different mantle processes operative at diverse geodynamic settings during the Neoarchean time. The Bababudan greenstone belt of western and Gadwal greenstone belt of eastern Dharwar Cratons are dominantly composed of high MgO volcanic rocks which, based on distinct geochemical characteristics, have been identified as komatiites and boninites respectively. The Bababudan komatiites are essentially composed of olivine and clinopyroxene with rare plagioclase tending towards komatiitic basalts. The Gadwal boninites contain clinopyroxene, recrystallized hornblende with minor orthopyroxene, plagioclase and sulphide minerals. The Bababudan komatiites are Al-undepleted type (Al2O3/TiO2 = 23-59) with distinctly high MgO (27.4-35.8 wt.%), Ni (509-1066 ppm) and Cr (136-3036 ppm) contents. These rocks have low ?PGE (9-42 ppb) contents with 0.2-2.4 ppb Iridium (Ir), 0.2-1.4 ppb Osmium (Os) and 0.4-4.4 ppb Ruthenium (Ru) among Iridium group PGE (IPGE); and 1.4-16.2 ppb Platinum (Pt), 2.8-19 ppb Palladium (Pd) and 0.2-9.8 ppb Rhodium (Rh) among Platinum group PGE (PPGE). The Gadwal boninites are high-Ca boninites with CaO/Al2O3 ratios varying between 0.8 and 1.0, with 12-24 wt.% MgO, 821-1168 ppm Ni and 2307-2765 ppm Cr. They show higher concentration of total PGE (82-207 ppb) with Pt concentration ranging from 13 to 19 ppb, Pd between 65 and 180 ppb and Rh in the range of 1.4-3 ppb compared to the Bababudan komatiites. Ir, Os and Ru concentrations range from 0.6 to 2.2 ppb, 0.2 to 0.6 ppb and 1.4 to 2.6 ppb respectively in IPGE. The PGE abundances in Bababudan komatiites were controlled by olivine fractionation whereas that in Gadwal boninites were influenced by fractionation of chromite and sulphides. The Al-undepleted Bababudan komatiites are characterized by low CaO/Al2O3, (Gd/Yb)N, (La/Yb)N, with positive Zr, Hf, Ti anomalies and high Cu/Pd, Pd/Ir ratios at low Pd concentrations suggesting the derivation of parent magma by high degrees (>30%) partial melting of mantle under anhydrous conditions at shallow depth with garnet as a residual phase in the mantle restite. The komatiites are geochemically analogous to Al-undepleted Munro type komatiites and their PGE compositions are consistent with Alexo and Gorgona komatiites. The S-undersaturated character of Bababudan komatiites is attributed to decompression and assimilation of lower crustal materials during magma ascent and emplacement. In contrast, the higher Al2O3/TiO2, lower (Gd/Yb)N, for Gadwal boninites in combination with negative Nb, Zr, Hf, Ti anomalies and lower Cu/Pd at relatively higher Pd/Ir and Pd concentrations reflect high degree melting of refractory mantle wedge under hydrous conditions in an intraoceanic subduction zone setting. Higher Pd/Ir ratios and S-undersaturation of these boninites conform to influx of fluids derived by dehydration of subducted slab resulting into high fluid pressure and metasomatism of mantle wedge.
DS201707-1361
2017
Ganguly, S.Saha, A., Ganguly, S., Ray, J., Koeberl, C., Thoni, M., Sarbajna, C., Sawant, S.S.Petrogenetic evolution of Cretaceous Samchampi Samteran alkaline complex, Mikir Hills, northeast India: implications on multiple melting events of heterogeneous plume and metasomatized sub continental lithospheric mantle.Gondwana Research, Vol. 48, pp. 237-256.Indiacarbonatite

Abstract: The Samchampi (26° 13?N: 93° 18?E)-Samteran (26° 11?N: 93° 25?E) alkaline complex (SSAC) occurs as an intrusion within Precambrian basement gneisses in the Karbi-Anglong district of Assam, Northeastern India. This intrusive complex comprises a wide spectrum of lithologies including syenite, ijolite-melteigite, alkali pyroxenite, alkali gabbro, nepheline syenite and carbonatite (nepheline syenites and carbonatites are later intrusives). In this paper, we present new major, trace, REE and Sr-Nd isotope data for different lithologies of SSAC and discuss integrated petrological and whole rock geochemical observations with Sr-Nd isotope systematics to understand the petrogenetic evolution of the complex. Pronounced LILE and LREE enrichment of the alkaline-carbonatite rocks together with steep LREE/HREE profile and flat HREE-chondrite normalized patterns provide evidence for parent magma generation from low degree partial melting of a metasomatized garnet peridotite mantle source. LILE, HFSE and LREE enrichments of the alkaline-silicate rocks and carbonatites are in agreement with the involvement of a mantle plume in their genesis. Nb-Th-La systematics with incompatible trace element abundance patterns marked by positive Nb-Ta anomalies and negative K, Th and Sr anomalies suggest contribution from plume-derived OIB-type mantle with recycled subduction component and a rift-controlled, intraplate tectonic setting for alkaline-carbonatite magmatism giving rise to the SSAC. This observation is corroborated by enriched 87Sr/86Srinitial (0.705562 to 0.709416) and 143Nd/144Ndinitial (0.512187 to 0.512449) ratios for the alkaline-carbonatite rocks that attest to a plume-related enriched mantle (~ EM II) source in relation to the origin of Samchampi-Samteran alkaline complex. Trace element chemistry and variations in isotopic data invoke periodic melting of an isotopically heterogeneous, metasomatized mantle and generation of isotopically distinct melt batches that were parental to the different rocks of SSAC. Various extents of plume-lithosphere interaction also accounts for the trace element and isotopic variations of SSAC. The Srinitial and Ndinitial (105 Ma) isotopic compositions (corresponding to ?Nd values of ? 6.37 to ? 1.27) of SSAC are consistent with those of Sung Valley, Jasra, Rajmahal tholeiites (Group II), Sylhet Traps and Kerguelen plateau basalts.
DS201903-0515
2019
Ganguly, S.Han, Y-S., Santosh, M., Ganguly, S., Li, S-S.Evolution of a Mesoarchean suprasubduction zone mantle wedge in the Dharwar Craton, southern India: evidence from petrology, geochemistry, zircon U-Pb geochronology, and Lu-Hf isotopes.Geological Journal, doi:10.1002/gj.3440Indiacraton

Abstract: Petrological, geochemical, and zircon U-Pb geochronological features of Archean ultramafic-mafic complexes formed in subduction?related settings provide significant insights into mantle source and geodynamic processes associated with subduction-accretion?collision events in the early Earth. Here, we investigate a suite of serpentinized dunite, dunite, pyroxenite, and clinopyroxenite from an ultramafic complex along the collisional suture between the Western Dharwar Craton (WDC) and the Central Dharwar Craton (CDC) in southern India. We present petrology, mineral chemistry, zircon U-Pb geochronology, rare earth element (REE), Lu-Hf isotopes, and whole?rock geochemistry including major, trace element, and platinum?group element (PGE) data with a view to investigate the magmatic and metasomatic processes in the subduction zone. Mineral chemistry data from chromite associated with the serpentinised ultramafic rocks show distinct characteristics of arc?related melt. Zircon U-Pb data from the ultramafic suite define different age populations, with the oldest ages at 2.9 Ga, and the dominant age population showing a range of 2.8-2.6 Ga. The early Paleoproterozoic (ca. 2.4 Ga) metamorphic age is considered to mark the timing of collision of the two WDC and CDC. Zircon REE patterns suggest the involvement continental crust components in the magma source. Zircon Lu-Hf analysis yields both positive and negative ?Hf(t) values from ?3.9 to 1.5 with Hf?depleted model ages (TDM) of 3,041-3,366 Ma for serpentinised dunite and ?0.2-2.0 and 2,833-2,995 Ma for pyroxenite, suggesting that the magma was sourced from depleted mantle and was contaminated with the ancient continental crust. Geochemical data show low MgO/SiO2 values and elevated Al2O3/TiO2 ratios, implying subduction?related setting. The serpentinized dunites and dunites show mild LREE enrichment over HREE, with relatively higher abundance of LILE (Ba, Sr) and depletion in HFSE (Nb, Zr), suggesting fluid-rock interaction, melt impregnation, and refertilization processes. The PGE data suggest olivine, chromite, and sulphide fractionations associated with subduction processes. Our study on the Mesoarchean to Neoarchean ultramafic complex provides important insights to reconstruct the history of the crust-mantle interaction in an Archean suprasubduction zone mantle wedge.
DS202005-0761
2019
Ganguly, S.Singh, T.D., Manikyamba, C., Subramanyam, K.S.V., Ganguly, S., Khelen, A., Ramakrsihna Reddy, N.Mantle heterogeneity, plume-lithosphere interaction at rift controlled ocean-continent transition zone: evidence from trace PGE geochemistry of Vempalle flows, Cuddapah basin India.Geoscience Frontiers, in press, 20p. PdfIndiaREE

Abstract: This study reports major, trace, rare earth and platinum group element compositions of lava flows from the Vempalle Formation of Cuddapah Basin through an integrated petrological and geochemical approach to address mantle conditions, magma generation processes and tectonic regimes involved in their formation. Six flows have been identified on the basis of morphological features and systematic three-tier arrangement of vesicular-entablature-colonnade zones. Petrographically, the studied flows are porphyritic basalts with plagioclase and clinopyroxene representing dominant phenocrystal phases. Major and trace element characteristics reflect moderate magmatic differentiation and fractional crystallization of tholeiitic magmas. Chondrite-normalized REE patterns corroborate pronounced LREE/HREE fractionation with LREE enrichment over MREE and HREE. Primitive mantle normalized trace element abundances are marked by LILE-LREE enrichment with relative HFSE depletion collectively conforming to intraplate magmatism with contributions from sub-continental lithospheric mantle (SCLM) and extensive melt-crust interaction. PGE compositions of Vempalle lavas attest to early sulphur-saturated nature of magmas with pronounced sulphide fractionation, while PPGE enrichment over IPGE and higher Pd/Ir ratios accord to the role of a metasomatized lithospheric mantle in the genesis of the lava flows. HFSE-REE-PGE systematics invoke heterogeneous mantle sources comprising depleted asthenospheric MORB type components combined with plume type melts. HFSE-REE variations account for polybaric melting at variable depths ranging from garnet to spinel lherzolite compositional domains of mantle. Intraplate tectonic setting for the Vempalle flows with P-MORB affinity is further substantiated by (i) their origin from a rising mantle plume trapping depleted asthenospheric MORB mantle during ascent, (ii) interaction between plume-derived melts and SCLM, (iii) their rift-controlled intrabasinal emplacement through Archean-Proterozoic cratonic blocks in a subduction-unrelated ocean-continent transition zone (OCTZ). The present study is significant in light of the evolution of Cuddapah basin in the global tectonic framework in terms of its association with Antarctica, plume incubation, lithospheric melting and thinning, asthenospheric infiltration collectively affecting the rifted margin of eastern Dharwar Craton and serving as precursors to supercontinent disintegration.
DS201212-0026
2012
Ganino, C.Arndt, N., Ganino, C.Deposits formed by sedimentary and surface processes.Metals and Society, and introduction to Economic Geology, Springer Publ., Chapter 5 pp. 113-140.GlobalAlluvials
DS200612-0424
2006
Ganley, M.Ganley, M.Conflict: the sixth C.Canadian Diamonds, Summer, pp. 26-32, 48.AfricaHistory - Kimberley Process
DS200612-0425
2005
Ganley, M.Ganley, M.Frozen in time... the North's regulatory process is too slow. Can anything be done to pull the process forward.Mining North, pp. 28,30,31.Canada, Northwest TerritoriesNews item - legal not specific to diamonds
DS200712-0345
2006
Ganley, M.Ganley, M.Artist of the DEAL. Profile of Eira Thomas and chosen Canadian Diamonds 2006 Person of the Year.Canadian Diamonds, pp. 27-32.CanadaNews item - profile Eira Thomas
DS200712-0346
2007
Ganley, M.Ganley, M.Mind the gap.... Diavik mine set a record for diamond production in 2006.. 9.8 million carats.Canadian Diamonds, Spring, pp. 26-30.Canada, Northwest TerritoriesDeposit - Diavik - production
DS200812-0381
2007
Ganley, M.Ganley, M.Target practice .. Government of NWT has suffered share of setbacks and blunders .. with new legislative assembly in place, might it improve its aim?Canadian Diamonds, Fall, pp.20-24.Canada, Northwest TerritoriesOverview - legal
DS200812-0382
2008
Ganley, M.Ganley, M.Will Tahera make it?UpHere Business, Vol. 1, 1, pp. 32-33,34, 36,38.Canada, NunavutJericho mine
DS1993-0480
1993
Gann, J.T.Gann, J.T.MudScan; PC based sidescan sonar real-time dat a acquisition, logging and display systemUnited States Geological Survey (USGS) Open File, No. 93-0242, 23p. $ 3.50GlobalComputer, Program - MudScan
DS201504-0185
2015
Ganne, J.Block, S., Ganne, J., Baratoux, A.Z., Parra-Avila, L.A., Jessell, M., Ailleres, L., Siebenaller, L.Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) Orogeny, NW Ghana, West African craton.Journal of Metamorphic Geology, Vol. 33, 5, pp. 463-494.Africa, GhanaGeochronology

Abstract: New petrological and geochronological data are presented on high-grade ortho- and paragneisses from northwestern Ghana, forming part of the Paleoproterozoic (2.25-2.00 Ga) West African Craton. The study area is located in the interference zone between N-S and NE--SW-trending craton-scale shear zones, formed during the Eburnean orogeny (2.15-2.00 Ga). High-grade metamorphic domains are separated from low-grade greenstone belts by high-strain zones, including early thrusts, extensional detachments and late-stage strike-slip shear zones. Paragneisses sporadically preserve high-pressure, low-temperature (HP-LT) relicts, formed at the transition between the blueschist facies and the epidote-amphibolite sub-facies (10.0-14.0 kbar, 520-600 °C), and represent a low (~15 °C km?1) apparent geothermal gradient. Migmatites record metamorphic conditions at the amphibolite-granulite facies transition. They reveal a clockwise pressure-temperature-time (P-T-t) path characterized by melting at pressures over 10.0 kbar, followed by decompression and heating to peak temperatures of 750 °C at 5.0-8.0 kbar, which fit a 30 °C km?1 apparent geotherm. A regional amphibolite facies metamorphic overprint is recorded by rocks that followed a clockwise P-T-t path, characterized by peak metamorphic conditions of 7.0-10.0 kbar at 550-680 °C, which match a 20-25 °C km?1 apparent geotherm. These P-T conditions were reached after prograde burial and heating for some rock units, and after decompression and heating for others. The timing of anatexis and of the amphibolite facies metamorphic overprint is constrained by in-situ U-Pb dating of monazite crystallization at 2138 ± 7 and 2130 ± 7 Ma respectively. The new data set challenges the interpretation that metamorphic breaks in the West African Craton are due to diachronous Birimian ‘basins’ overlying a gneissic basement. It suggests that the lower crust was exhumed along reverse, normal and transcurrent shear zones and juxtaposed against shallow crustal slices during the Eburnean orogeny. The craton in NW Ghana is made of distinct fragments with contrasting tectono-metamorphic histories. The range of metamorphic conditions and the sharp lateral metamorphic gradients are inconsistent with ‘hot orogeny’ models proposed for many Precambrian provinces. These findings shed new light on the geodynamic setting of craton assembly and stabilization in the Paleoproterozoic. It is suggested that the metamorphic record of the West African Craton is characteristic of Paleoproterozoic plate tectonics and illustrates a transition between Archean and Phanerozoic orogens.
DS201701-0012
2016
Ganne, J.Ganne, J., Feng, X., Rey, P., De Andrade, V.Statistical petrology reveals a link between supercontinents cycle and mantle global climate.American Mineralogist, Vol. 101, pp. 2768-2773.MantleGeostatistics

Abstract: The breakup of supercontinents is accompanied by the emplacement of continental flood basalts and dike swarms, the origin of which is often attributed to mantle plumes. However, convection modeling has showed that the formation of supercontinents result in the warming of the sub-continental asthenospheric mantle (SCAM), which could also explain syn-breakup volcanism. Temperature variations during the formation then breakup of supercontinents are therefore fundamental to understand volcanism related to supercontinent cycles. Magmatic minerals record the thermal state of their magmatic sources. Here we present a data mining analysis on the first global compilation of chemical information on magmatic rocks and minerals formed over the past 600 million years: a time period spanning the aggregation and breakup of Pangea, the last supercontinent. We show that following a period of increasingly hotter Mg-rich magmatism with dominant tholeiitic affinity during the aggregation of Pangea, lower-temperature minerals crystallized within Mg-poorer magma with a dominant calc-alkaline affinity during Pangea disassembly. These trends reflect temporal changes in global mantle climate and global plate tectonics in response to continental masses assembly and dispersal. We also show that the final amalgamation of Pangea at ~300 Myr led to a long period of lithospheric collapse and cooling until the major step of Pangea disassembly started at ~125 Myr. The geological control on the geosphere magma budget has implications on the oxidation state and temperature of the Earth’s outer envelopes in the Phanerozoic and may have exerted indirect influence on the evolution of climate and life on Earth.
DS201706-1070
2017
Ganne, J.Ganne, J., Feng, X.Primary magmas and mantle temperatures through time.Geochemistry, Geophysics, Geosystems: G3, Vol. 18, pp. 872-888.Mantlegeothermometry

Abstract: Chemical composition of mafic magmas is a critical indicator of physicochemical conditions, such as pressure, temperature, and fluid availability, accompanying melt production in the mantle and its evolution in the continental or oceanic lithosphere. Recovering this information has fundamental implications in constraining the thermal state of the mantle and the physics of mantle convection throughout the Earth's history. Here a statistical approach is applied to a geochemical database of about 22,000 samples from the mafic magma record. Potential temperatures (Tps) of the mantle derived from this database, assuming melting by adiabatic decompression and a Ti-dependent (Fe2O3/TiO2?=?0.5) or constant redox condition (Fe2+/?Fe?=?0.9 or 0.8) in the magmatic source, are thought to be representative of different thermal “horizons” (or thermal heterogeneities) in the ambient mantle, ranging in depth from a shallow sublithospheric mantle (Tp minima) to a lower thermal boundary layer (Tp maxima). The difference of temperature (?Tp) observed between Tp maxima and minima did not change significantly with time (?170°C). Conversely, a progressive but limited cooling of ?150°C is proposed since ?2.5 Gyr for the Earth's ambient mantle, which falls in the lower limit proposed by Herzberg et al. [2010] (?150-250°C hotter than today). Cooling of the ambient mantle after 2.5 Ga is preceded by a high-temperature plateau evolution and a transition from dominant plumes to a plate tectonics geodynamic regime, suggesting that subductions stabilized temperatures in the Archaean mantle that was in warming mode at that time.
DS201810-2317
2018
Ganne, J.Ganne, J., Feng, X.Magmatism: a crustal and geodynamic perspective.Journal of Structual Geology, Vol. 11, pp. 329-335.Mantlemagmatism

Abstract: The Earth's continental crust constitutes a major interface between the inner and outer envelops of the planet, controlling the differentiation of magmas produced in the mantle and their transfer to the surface. This close link facilitates the use of different chemical proxies to qualitatively unravel the crustal thickness related to fossil magmatic systems based on the message carried by magmas. This paper aims to bridge different results of statistical petrology, recently obtained at different scales of observation, in a global geodynamic model. Statistical analyses applied to a large multidimensional database of magmatic rocks show that crustal thickness could actually exert a first-order control on the composition of magmas, which become more calc-alkaline and comparatively less tholeiitic with increasing crustal thickness. Using this correlation, we document the progressive build-up of a thick (>40?km) Jurassic to Cretaceous accretionary belt along the Circum-Pacific Orogenic Belts (CPOB) that bounded the Panthalassa Ocean. The destruction of this thick belt started at ca. 125 Ma and was initially recorded by the thinnest magmatic systems hosting amphibole-bearing magma. Thinning of the CPOB became widespread in the northern regions of western America and in the western Pacific after ca. 75 Ma, possibly in response to oceanic plate segmentation, which triggered slab rollback and overriding plate extension. This chemical evolution is superimposed on a more global evolution of magma controlled by the temperature of the mantle that has gradually decreased since 200 Ma. Although the relative contribution of crust vs mantle cooling in the chemical signature of magmatic rocks should be further explored in the future, our results offer a new global perspective of the magmatic history of Pangea, the last supercontinent.
DS200512-0312
2005
Gannicott, R.Gannicott, R.Aber Diamond Corporation - charting its own unique course in response to its unique position.CIM Mining Rocks April 24-27th. Toronto Annual Meeting, Paper# 1923 AbstractCanada, Northwest TerritoriesNews item - Aber Diamond
DS200612-0426
2006
Gannicott, R.Gannicott, R.Joint ventures: diamond mines and jewellers.Prospectors and Developers Association of Canada, March 1p. abstractCanada, Northwest TerritoriesEconomics
DS200612-0427
2006
Gannicott, R.Gannicott, R.Strategy to grow a diamond mining company.SEG 2006 Conference, Wealth Creation in the Minerals Industry, May 14-16, Keystone Colorado USA, Abtract Volume p. 27. ( 1p.)Canada, Northwest TerritoriesMining methods - Diavik
DS201012-0217
2010
Gannicott, R.Gannicott, R.A diamond company's ride through the economic turmoil.PDAC 2010, March 8, abstractGlobalHarry Winston Diamond Corporation
DS2001-0353
2001
Gannicott, R.A.Gannicott, R.A.Canadian diamonds, baby-boomers and the American economy: a unique resource opportunity.Prospectors and Developers Association of Canada (PDAC) 2001, 1p. abstractGlobalDiamond - exploration brief overview, Investor - economics
DS201810-2336
2018
Ganno, S.Kankeu, B., Greiling, R.O., Nzenti, J.P., Ganno, S., Danguene, P.Y.E., Basshahak, J., Hell, J.V.Contrasting Pan-African structural styles at the NW margin of the Congo shield in Cameroon.Journal of African Earth Sciences, Vol. 146, pp. 28-47.Africa, Camerooncraton

Abstract: Field, microstructural, and anisotropy of magnetic susceptibility (AMS, magnetic fabrics) studies assessed the Pan-African deformational history and strain geometry at the southern margin of the Central African Fold Belt (CAFB) against the older, cratonic basement of the Congo Shield (CS). Reflected light microscopy and thermomagnetic studies supported the identification of magnetic minerals. Data cover a low angle thrust margin (Mbengis-Sangmelima area) in the east and high angle shear zones cutting the margin (Kribi area) in the west, at the Atlantic coast. In the CS basement units, magnetic anisotropy is generally higher than in the low grade Pan-African units. In the latter, early D1/D2 shortening produced a flat-lying magnetic foliation parallel with the regional trend of the belt, a shallow magnetic lineation, and mostly oblate fabrics. Subsequent D3 deformation is only of local importance in the Mbengis-Sangmelima area. The magnetic lineation shows distinct maxima in NNE-SSW direction, parallel with the low angle tectonic transport direction. In the Kribi area, the NNE-SSW trending Kribi-Campo shear zone (KCSZ) affected both older rocks and Pan-African high grade metapelites of the Yaoundé unit together with their basal thrust. The early planar fabric (S1) was overprinted during D2 folding under relatively high T conditions, and subsequent D3 wrenching. Magnetic fabrics document a progressive change from oblate towards prolate ellipsoids towards the KCSZ. Magnetic foliations with medium to steep dips curve into the N-S to NE-SW orientation of the KCSZ, lineations follow the same trend with shallow to medium plunges. This fabric implies that the KCSZ is a Pan-African strike-slip shear zone with a subordinate component of compression. Strike-slip tectonics in the west (KCSZ) and thrusting in the east imply N-S to NE-SW convergence during Pan-African terrane assembly against the present northern margin of the CS. In addition, the KCSZ may separate the CS from the São Francisco Craton in Brazil and thus be the northern part of a link connecting the CAFB to the West Congo Belt in the south. This putative Pan-African link separated the São Francisco Craton from the Congo Shield prior to Mesozoic Gondwana break-up.
DS2002-0229
2002
GannounBurton, K.W., Gannoun, Birck, Allegre, Schiano,AlardThe compatibility of rhenium and osmium in natural olivine and their behaviour during mantle melting...Earth and Planetary Science Letters, Vol.198,1-2,pp.63-76., Vol.198,1-2,pp.63-76.MantleMineralogy - olivine, Basalt genesis
DS2002-0230
2002
GannounBurton, K.W., Gannoun, Birck, Allegre, Schiano,AlardThe compatibility of rhenium and osmium in natural olivine and their behaviour during mantle melting...Earth and Planetary Science Letters, Vol.198,1-2,pp.63-76., Vol.198,1-2,pp.63-76.MantleMineralogy - olivine, Basalt genesis
DS1998-0463
1998
Gannoun, A.Gannoun, A., Birck, J.L., Bourdon, B., Allegre, C.J.Re Os systematics in orogenic peridotite massifs and contraints on the petrogenesis of pyroxenites.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 496-7.Morocco, Spain, FranceUltramafics, Deposit - Beni Bouzra, Ronda, Lherz
DS200512-0008
2005
Gannoun, A.Alard, O., Luguet, A., Pearson, N.J., Griffin, W.L., Lorand, J.P., Gannoun, A., Burton, K.W., O'Reilly, S.Y.In situ Os isotopes in abyssal peridotites bridge the isotopic gap between MORBS and their source mantle.Nature, Vol. 436, No. 7053, Aug. 18, pp. 1005-1108.MantleGeochronology
DS201112-0416
2011
Gannoun, A.Harvey, J., Dale, C.W., Gannoun, A., Burton, K.W.Osmium mass balance in peridotite and the effects of mantle derived sulphides on basalt petrogenesis.Geochimica et Cosmochimica Acta, Vol. 75, 9, pp. 5574-5596.United States, New Mexico, Colorado PlateauKilbourne
DS201504-0199
2015
Gannoun, A.Gannoun, A., Burton, K.W., Barfod, D.N., Schiano, P., Vlastelic, I., Halliday, A.N.Resolving mantle and magmatic processes in basalts from the Cameroon volcanic line using the Re-Os isotopic system.Lithos, Vol. 224-5, pp. 1-12.Africa, CameroonAlkaline rocks, basalts
DS201801-0039
2017
Gannoun, A.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.
DS201808-1775
2017
Gannoun, A.Paquette, J.L., Ionov, D.A., Agashev, A.M., Gannoun, A., Nikolenko, E.I.Age, provenance and Precambrian evolution of the Anabar shield from U Pb and Lu Hf isotope dat a on detrital zircons, and the history of the northern and central Siberian craton.Precambrian Research, Vol. 301, pp. 134-144.Russiacraton

Abstract: The Anabar shield in northern Siberia is one of the world’s least studied Precambrian areas, and provides a ‘window’ into the crustal basement of the central and northern Siberian craton. We report U-Pb and Hf isotope data for detrital zircons sampled in a profile across its major structural units. They define a U-Pb age range from 1.8 to 3.4 Ga with three main periods: 1.8-2.0 Ga, 2.4-2.8 Ga and 3.0-3.4 Ga. The oldest zircons yield super-chondritic ?Hf(t) implying that the parental magmas of their source rocks were juvenile, i.e. formed from depleted mantle (DM). Thus, the crustal basement of the Anabar shield, and probably the whole central and northern Siberian craton, started to form in the mid-Paleoarchean, and included no recycled crust. Zircons with 2.5-2.7 Ga ages define two ?Hf(t) intervals. One is super-chondritic (+2 to +7) implying juvenile sources, the other is sub-chondritic (?3 to ?12) indicative of recycled crust, probably formed at 3.2-3.4 Ga, in magma sources. Nearly all 1.8-2.0 Ga zircons have sub-chondritic ?Hf(t) (?2 to ?29) implying derivation from sources dominated by recycled crust formed at ?2.6 Ga and ?3.4 Ga and little or no juvenile addition. These events accompanied amalgamation of the entire craton by welding of Archean domains. The Bekelekh unit of the Daldyn series has the highest proportion of ?2.6 Ga zircons and may be the oldest ‘nucleus’ of the Anabar shield, whereas the Kilegur unit of the same series is essentially Proterozoic (1.95 Ga). The largest amount of 3.1-3.4 Ga zircons, as well as common 2.6-2.7 Ga zircons, occur in the Ambardakh unit of the Upper Anabar series. Our data suggest alternation of areas with dominant ages of 1.95 Ga and ?2.6 Ga, with the younger zircons coming from granites and granulites, and the older ones from gneisses. They show no evidence for significant ages differences for the Anabar and Olenek provinces. The final amalgamation of the entire Siberian craton by welding of Archean blocks, may have taken place at around 1954 ± 6 Ma.
DS1991-0409
1991
Gans, P.B.Dumitru, T.A., Gans, P.B., Foster, D.A., Miller, E.L.Refrigeration of the western Cordilleran lithosphere during Laramide shallow angle subductionGeology, Vol. 19, No. 11, November pp. 1145-1148CordilleraSubduction, Tectonics
DS1998-0464
1998
Gans, P.B.Gans, P.B., Bohrson, W.A.Suppression of volcanism during rapid extension in the Basin and Rangeprovince, United StatesScience, Vol. 279, No. 5347, Jan. 2, pp. 66-68Nevada, Basin and Rangevolcanism., tectonics
DS200512-0910
2005
Gans, P.B.Root, D.B., Hacker, B.R., Gans, P.B., Ducea, E.A., Eide, J.L.Discrete ultrahigh prssure domains in the Western Gneiss region, Norway: implications for formation and exhumation.Journal of Metamorphic Geology, Vol. 23, 1, pp. 45-61.Europe, NorwayUHP
DS200912-0275
2009
Gans, P.B.Hacker, B.R., Wallis, S.R., McWilliams, M.O., Gans, P.B.40 Ar 39AR constraints on the tectonic history and architecture of the ultrahigh pressure Sulu orogen.Journal of Metamorphic Geology, Vol. 27, 9, pp. 827-844.ChinaUHP
DS1960-1107
1969
Ganster, M.Ganster, M., Stearns, P.G.Configuration and Source of Anomalous Magnetic Field Near Gordonsville in Smith County, Tennessee.Tennessee Academy of Science Journal, Vol. 44, No. 2, P. 49, (abstract.).United States, Tennessee, Central StatesBlank
DS201611-2109
2016
Ganti, V.Ganti, V., Von Hagke, C., Scherler, D., Lamb, M.P., Fischer, W.W., Avouac, J-P.Time scale bias in erosion rates of glaciated landscapes.Science Advances, Vol. 2, 10, 3p.GlobalGlaciology

Abstract: Deciphering erosion rates over geologic time is fundamental for understanding the interplay between climate, tectonic, and erosional processes. Existing techniques integrate erosion over different time scales, and direct comparison of such rates is routinely done in earth science. On the basis of a global compilation, we show that erosion rate estimates in glaciated landscapes may be affected by a systematic averaging bias that produces higher estimated erosion rates toward the present, which do not reflect straightforward changes in erosion rates through time. This trend can result from a heavy-tailed distribution of erosional hiatuses (that is, time periods where no or relatively slow erosion occurs). We argue that such a distribution can result from the intermittency of erosional processes in glaciated landscapes that are tightly coupled to climate variability from decadal to millennial time scales. In contrast, we find no evidence for a time scale bias in spatially averaged erosion rates of landscapes dominated by river incision. We discuss the implications of our findings in the context of the proposed coupling between climate and tectonics, and interpreting erosion rate estimates with different averaging time scales through geologic time.
DS201505-0250
2015
Ganuza, M.L.Ferracutti, G.R., Gargiulo, M.F., Ganuza, M.L., Bjerg, E.A., Castro, S.M.Determination of the spinel group end-members based on electron microprobe analyses.Mineralogy and Petrology, Vol. 109, 2, pp. 153-160.TechnologyGeochronology
DS202106-0921
2021
Ganuza, M.L.Antonini, A., Ganuza, M.L. , Ferracutti, G., Gagiulo, M.F., Matkovic, K., Groller, E., Bjerg, E.A., Castro, S.M.Spinel web: an interactive web application for visualizing the chemical composition of spinel group minerals. ** not specific to diamondsEarth Science Informatics, Vol. 14, pp. 521-528. pdfMantletectonics

Abstract: The spinel group minerals provide useful information regarding the geological environment in which the host rocks were formed, constituting excellent petrogenetic indicators, and guides in the search for mineral deposits of economic interest. In this article, we present the Spinel Web, a web application to visualize the chemical composition of spinel group minerals. Spinel Web integrates most of the diagrams commonly used for analyzing the chemical characteristics of the spinel group minerals. It incorporates parallel coordinates and a 3D representation of the spinel prisms. It also provides coordinated views and appropriate interactions for users to interact with their datasets. Spinel Web also supports semi-automatic categorization of the geological environment of formation through a standard Web browser.
DS2001-1061
2001
Ganvir, D.V.Shasidharan, K., Ganvir, D.V.Search for kimberlite lamproite in parts of Chanrapur Garchiroli and Nanded districts, Maharashtra.India Geological Survey Records, No. 133, 6, p. 37-42.IndiaNews item, exploration
DS200612-1225
2001
Ganvir, D.V.Sashidharan, K., Ganvir, D.V., Mohanty, A.K.Search for kimberlites and lamproites in the western part of the Bastar Craton, Maharashtra.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 629-634.India, MaharashtraDiamond exploration - geochemistry comparison Monastery
DS201412-0263
2014
Ganz, M.Ganz, M.The state of the industry as 2014 begins.Hayashalom Magazine, January No. 213, pp. 8-11.GlobalEconomics
DS201412-0264
2014
Ganz, M.Ganz, M.The GIA has become our achilles heel. Slow documentation.Hayashalom Magazine, No. 215, pp. 8-11.GlobalGIA and documents
DS200912-0860
2009
GaoZheng, J.P., Griffin, W.L., O'Reilly, S.Y., Sun, M., Zheng, S., Pearson, N., Gao, Yu, Su, Tang, Liu, WuAge and composition of granulite and pyroxenite xenoliths in Hannuoba basalts reflect Paleogene underplating beneath the North Chin a craton.Chemical Geology, Vol. 264, 1-4, pp. 266-280.ChinaXenoliths
DS201608-1441
2016
Gao, B.Song, Z., Lu, T., Tang, S., Ke, J., Su, J., Gao, B., Bi, L., Wang, D.Identification of colourless HPHT grown synthetic diamonds from Shandong China.The Journal of Gemmology, Vol. 35, 2, pp. 14-147.ChinaSynthetics
DS200812-0383
2008
Gao, C.Gao, C., Liu, Y.Moissanite bearing carbonatite xenoliths from Cenozoic basalt, North China: products of ancient oceanic crust subduction.Goldschmidt Conference 2008, Abstract p.A292.ChinaCarbonatite
DS200812-0680
2008
Gao, C.Liu, Y., Gao, S., Gao, C., Zong, K.Recycling of lower continental crust in the Trans-North Chin a Orogen: evidence from zircon dating of mantle composite xenoliths.Goldschmidt Conference 2008, Abstract p.A563.ChinaCraton
DS201112-0343
2011
Gao, C.Gao, C.Surficial geology mapping and till sampling in the Chapleau area, northern Ontario. ( Kapuskasing Structual Zone ) and potential for kimberlite.Ontario Summary of Field Work and Other Activities, Ontario Open File 6270, pp.20-1-20-5.Canada, OntarioGeochemistry
DS201212-0227
2012
Gao, C.Gao, C., McAndrews, J.H., Wang, X., Menzies, J., Turton, C.L., Wood, B.D., Pei, J., Kodors, C.Glaciation of North America in the James Bay Lowland, Canada, 3-5 Ma.Geology, Vol. 40, 11, pp. 975-978.Canada, Ontario, James Bay LowlandsGeomorphology
DS201212-0627
2012
Gao, C.Schmidt, M.W., Rohrbach, A., Gao, C., Connolly, J.A.D.The role of redox equilibration temperatures during carbon transfer in the mantle and the stability of carbides in the mantle.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractMantleRedox
DS201501-0030
2014
Gao, C.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
DS201605-0837
2016
Gao, C.Gao, C., Crabtree, D.C., Dyer, R.D.Indicator mineral and geochemistry dat a for a till and alluvium sampling survey in the McFaulds Lake ( Ring of Fire) area, northern Ontario. Mentions KIMS.Ontario Geological Survey Report and Data, Report 6309, Data release 322.Canada, OntarioGeochemistry - KIMS
DS201703-0406
2017
Gao, C.He, D., Liu, Y., Gao, C., Chen, C., Hu, Z., Gao, S.SiC dominated ultra-reduced mineral assemblage in carbonatitic xenoliths from the Dalihu basalt, Inner Mongolia, China.American Mineralogist, Vol. 102, pp. 312-320.China, MongoliaCarbonatite

Abstract: SiC and associated ultra-reduced minerals were reported in various geological settings, however, their genesis and preservation mechanism are poorly understood. Here, we reported a SiC-dominated ultra-reduced mineral assemblage, including SiC, TiC, native metals (Si, Fe, and Ni) and iron silicide, from carbonatitic xenoliths in Dalihu, Inner Mongolia. All minerals were identified in situ in polished/thin sections. SiC is 20-50 ?m in size, blue to colorless in color, and usually identified in the micro-cavities within the carbonatitic xenolith. Four types of SiC polytypes were identified, which are dominated by ?-SiC (3C polytype) and 4H polytype followed by 15R and 6H. These SiC are featured by 13C-depleted isotopic compositions (?13C = ?13.2 to ?22.8‰, average = ?17.7‰) with obvious spatial variation. We provided a numerical modeling method to prove that the C isotopic composition of the Dalihu SiC can be well-yielded by degassing. Our modeling results showed that degassing reaction between graphite and silicate can readily produce the low ?13C value of SiC, and the spatial variations in C isotopic composition could have been formed in the progressive growth process of SiC. The detailed in situ occurring information is beneficial for our understanding of the preservation mechanism of the Dalihu ultra-reduced phase. The predominant occurrence of SiC in micro-cavities implies that exsolution and filling of CO2 and/or CO in the micro-cavities during the diapir rising process of carbonatitic melt could have buffered the reducing environment and separated SiC from the surrounding oxidizing phases. The fast cooling of host rock, which would leave insufficient time for the complete elimination of SiC, could have also contributed to the preservation of SiC.
DS202009-1676
2020
Gao, C.Zheng, H., Chen, H., Wu, C., Jiang, H., Gao, C., Kang, Q., Yang, C., Wang, D., Lai, C-K.Genesis of the supergiant Huayangchuan carbonatite-hosted uranium polymetallic deposit in the Qinling orogen, central China.Gondwana Research, Vol. 86, pp. 250-265.ChinaREE

Abstract: The newly-discovered supergiant Huayangchuan uranium (U)-polymetallic deposit is situated in the Qinling Orogen, Central China. The deposit contains economic endowments of U, Nb, Pb, Se, Sr, Ba and REEs, some of which (e.g., U, Se, and Sr) reaching super-large scale. Pyrochlore, allanite, monazite, barite-celestite and galena are the major ore minerals at Huayangchuan. Uranium is mainly hosted in the primary mineral of pyrochlore, and the mineralization is mainly hosted in or associated with carbonatite dikes. According to the mineral assemblages and crosscutting relationships, the alteration/mineralization at Huayangchuan comprises four stages, i.e., pegmatite REE mineralization (I), main mineralization (II), skarn mineralization (III) and post-ore alteration (IV). Coarse-grained euhedral allanite is the main Stage I REE mineral, and the pegmatite-hosted REE mineralization (ca. 1.8 Ga) occurs mostly in the shallow-level of northwestern Huayangchuan, corresponding to the Paleoproterozoic Xiong'er Group volcanic rocks (1.80-1.75 Ga) in the southern margin of North China Block. Carbonatite-hosted Stage II mineralization contributes to the majority of U-Nb-REE-Ba-Sr resources, and is controlled by the Huayangchuan Fault. Stage II mineralization can be further divided into the sulfate mineralization (barite-celestite) (II-A), alkali-rich U mineralization (aegirine-augite + pyrochlore + uraninite + uranothorite) (II-B) and REE (allanite + monazite + chevkinite)-U (pyrochlore + uraninite) mineralization (II-C) substages. Stage II mineralization may have occurred during the Late Triassic Mianlue Ocean closure. Skarn mineralization contributed to the majority of Pb and minor U-REE (uraninite-allanite) resources at Huayangchuan, and is spatially associated with the Late Cretaceous-Early Jurassic (Yanshanian) Huashan and Laoniushan granites. We suggested that hydrothermal fluids derived from the Laoniushan and Huashan granites may have reacted with the Triassic carbonatites, and formed the Huayangchuan Pb skarn mineralization. The mantle-derived Triassic carbonatites may have been fertilized by the U-rich subducting oceanic sediments, and were further enriched through reacting with the Proterozoic U-REE-rich pegmatite wallrocks at Huayangchuan. Ore-forming elements were likely transported in metal complexes (F?, and ), and deposited with the dilution of the complex concentration. This may have formed the distinct vertical mineralization zoning, i.e., sodic fenite-related alkali-U mineralization at depths and potassic fenite-related REE-U mineralization at shallow level.
DS202012-2258
2020
Gao, C.Zheng, H., Chen, H., Wu, C., Jiang, H., Gao, C., Kang, Q., Yang, C., Wang, D., Lai, C-k.Genesis of the supergiant Huayanchuan carbonatite-hosted uranium-plymetallic deposit in the Qinling Orogen, central China.Gondwana Research, Vol. 86, pp. 250-265. pdfChinadeposit - Huayangchuan

Abstract: The newly-discovered supergiant Huayangchuan uranium (U)-polymetallic deposit is situated in the Qinling Orogen, Central China. The deposit contains economic endowments of U, Nb, Pb, Se, Sr, Ba and REEs, some of which (e.g., U, Se, and Sr) reaching super-large scale. Pyrochlore, allanite, monazite, barite-celestite and galena are the major ore minerals at Huayangchuan. Uranium is mainly hosted in the primary mineral of pyrochlore, and the mineralization is mainly hosted in or associated with carbonatite dikes. According to the mineral assemblages and crosscutting relationships, the alteration/mineralization at Huayangchuan comprises four stages, i.e., pegmatite REE mineralization (I), main mineralization (II), skarn mineralization (III) and post-ore alteration (IV). Coarse-grained euhedral allanite is the main Stage I REE mineral, and the pegmatite-hosted REE mineralization (ca. 1.8 Ga) occurs mostly in the shallow-level of northwestern Huayangchuan, corresponding to the Paleoproterozoic Xiong'er Group volcanic rocks (1.80-1.75 Ga) in the southern margin of North China Block. Carbonatite-hosted Stage II mineralization contributes to the majority of U-Nb-REE-Ba-Sr resources, and is controlled by the Huayangchuan Fault. Stage II mineralization can be further divided into the sulfate mineralization (barite-celestite) (II-A), alkali-rich U mineralization (aegirine-augite + pyrochlore + uraninite + uranothorite) (II-B) and REE (allanite + monazite + chevkinite)-U (pyrochlore + uraninite) mineralization (II-C) substages. Stage II mineralization may have occurred during the Late Triassic Mianlue Ocean closure. Skarn mineralization contributed to the majority of Pb and minor U-REE (uraninite-allanite) resources at Huayangchuan, and is spatially associated with the Late Cretaceous-Early Jurassic (Yanshanian) Huashan and Laoniushan granites. We suggested that hydrothermal fluids derived from the Laoniushan and Huashan granites may have reacted with the Triassic carbonatites, and formed the Huayangchuan Pb skarn mineralization. The mantle-derived Triassic carbonatites may have been fertilized by the U-rich subducting oceanic sediments, and were further enriched through reacting with the Proterozoic U-REE-rich pegmatite wallrocks at Huayangchuan. Ore-forming elements were likely transported in metal complexes (F?, and ), and deposited with the dilution of the complex concentration. This may have formed the distinct vertical mineralization zoning, i.e., sodic fenite-related alkali-U mineralization at depths and potassic fenite-related REE-U mineralization at shallow level.
DS200812-0384
2008
Gao, E-G.Gao, E-G., Liu, H., Liu, L-F.The origin and tectonic frame of the Dabie Shan orogenic belt: constraints from geophysical data.Goldschmidt Conference 2008, Abstract p.A293.ChinaUHP
DS1996-0478
1996
Gao, H.Gao, H., Wang, J., Zhao, P.The updated kriging variance and optimal sample designMathematical Geology, Vol. 28, No. 3, pp. 295-313GlobalComputer, Program -kriging variance, sample design
DS2001-0354
2001
Gao, J.Gao, J., Klemd, R.Primary fluids entrapped at blueschist to eclogite transition: evidence from the Tainshan meta subductionContributions to Mineralogy and Petrology, Vol. 142, No. 1, Oct. pp. 1-14.China, NorthwestMineral chemistry, Subduction
DS2002-0862
2002
Gao, J.Klemd, R., Schroter, F.C., Will, T.M., Gao, J.P-T evolution of glauco phaneomphacite bearing HP - LT rocks in the eastern Tien Shan Orogen: Alpine type ..Journal of Metamorphic Geology, Vol. 20, No. 2, pp. 239-54.China, northwestTectonics - evidence, Ultrahigh pressure, UHP
DS2003-0436
2003
Gao, J.Gao, J., Klemd, R.Formation of HP LT rocks and their tectonic implications in the western TainshanLithos, Vol. 66, 1-2, Jan. pp. 1-22.ChinaGeochemistry
DS2003-0437
2003
Gao, J.Gao, J., Klemd, R.Formation of HP Lt rocks and their tectonic implications in the western TianshanLithos, Vol. 66, 3-4, January, pp. 1-22.ChinaMineral chemistry, Geochronology
DS2003-0438
2003
Gao, J.Gao, J., Klemd, R.Formation of HP LT rocks and their tectonic implications in the Western TienshanLithos, Vol. 66, 1-2, pp. 1-22.ChinaUHP - ultrahigh pressure
DS200412-0604
2003
Gao, J.Gao, J., Klemd, R.Formation of HP Lt rocks and their tectonic implications in the western Tian Shan Orogen, NW China: geochemical and age constrainLithos, Vol. 66, 3-4, January, pp. 1-22.ChinaMineral chemistry, Geochronology
DS200612-0715
2006
Gao, J.Klemd, R., Gao, J., John, T.Trace element enriched fluids released during slab dehydration: implications for oceanic slab mantle wedge transfer.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 22. abstract only.MantleSubduction
DS201112-0527
2011
Gao, J.Klemd, R., Scherer, J.E.E., Rondenay, S., Gao, J.Changes in dip of subducted slabs at depth: petrological and geochronological evidence from HP-UHP rocks (Tianshan, NW China).Earth and Planetary Science Letters, Vol. 310, 1-2, pp. 9-20.ChinaUHP
DS201703-0403
2017
Gao, J.Gao, J., Niu, J., Qin, S., Wu, X.Ultradeep diamonds originate from deep subducted sedimentary carbonates.Science China Earth Sciences, Vol. 60, 2, pp. 207-217.TechnologySubduction

Abstract: Diamonds are renowned as the record of Earth’s evolution history. Natural diamonds on the Earth can be distinguished in light of genetic types as kimberlitic diamonds (including peridotitic diamonds and eclogitic diamonds), ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds. According to the inclusion mineralogy, most diamonds originated from continental lithospheric mantle at depths of 140-250 km. Several localities, however, yield ultradeep diamonds with inclusion compositions that require a sublithospheric origin (>~250 km). Ultradeep diamonds exhibit distinctions in terms of carbon isotope composition, N-concentration, mineral inclusions and so on. The present study provides a systematic compilation concerning the features of ultradeep diamonds, based on which to expound their genesis affinity with mantle-carbonate melts. The diamond-parental carbonate melts are proposed to be stemmed from the Earth’s crust through subduction of oceanic lithosphere. Ultradeep diamonds are classified into a subgroup attaching to kimberlitic diamonds grounded by formation mechanism, and present connections in respect of carbon origin to eclogitic diamonds, ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds.
DS201706-1071
2016
Gao, J.Gao, J., Niu, J.J., Qin, S., Wu, X.Ultradeep diamonds originate from deep subducted sedimentary carbonates.Science China Earth Sciences, 12p. * engMantlesubduction, carbon cycle

Abstract: Diamonds are renowned as the record of Earth’s evolution history. Natural diamonds on the Earth can be distinguished in light of genetic types as kimberlitic diamonds (including peridotitic diamonds and eclogitic diamonds), ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds. According to the inclusion mineralogy, most diamonds originated from continental lithospheric mantle at depths of 140-250 km. Several localities, however, yield ultradeep diamonds with inclusion compositions that require a sublithospheric origin (>~250 km). Ultradeep diamonds exhibit distinctions in terms of carbon isotope composition, N-concentration, mineral inclusions and so on. The present study provides a systematic compilation concerning the features of ultradeep diamonds, based on which to expound their genesis affinity with mantle-carbonate melts. The diamond-parental carbonate melts are proposed to be stemmed from the Earth’s crust through subduction of oceanic lithosphere. Ultradeep diamonds are classified into a subgroup attaching to kimberlitic diamonds grounded by formation mechanism, and present connections in respect of carbon origin to eclogitic diamonds, ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds.
DS201707-1325
2016
Gao, J.Gao, J., Niu, J., Qin, S., Wu, X.Ultradeep diamonds originate from deep subducted sedimentary carbonates.Science China Earth Sciences, Vol. 60, 2, 3p.MantleUHP

Abstract: Diamonds are renowned as the record of Earth’s evolution history. Natural diamonds on the Earth can be distinguished in light of genetic types as kimberlitic diamonds (including peridotitic diamonds and eclogitic diamonds), ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds. According to the inclusion mineralogy, most diamonds originated from continental lithospheric mantle at depths of 140–250 km. Several localities, however, yield ultradeep diamonds with inclusion compositions that require a sublithospheric origin (>~250 km). Ultradeep diamonds exhibit distinctions in terms of carbon isotope composition, N-concentration, mineral inclusions and so on. The present study provides a systematic compilation concerning the features of ultradeep diamonds, based on which to expound their genesis affinity with mantle-carbonate melts. The diamond-parental carbonate melts are proposed to be stemmed from the Earth’s crust through subduction of oceanic lithosphere. Ultradeep diamonds are classified into a subgroup attaching to kimberlitic diamonds grounded by formation mechanism, and present connections in respect of carbon origin to eclogitic diamonds, ultrahigh-pressure metamorphic diamonds and ophiolitic diamonds.
DS201809-2085
2018
Gao, J.Sharma, S.K., Chen, B., Gao, J., Lai, X.Micro-Raman investigations of diamond genesis during slab-mantle interaction.Goldschmidt Conference, 1p. AbstractMantlediamond genesis

Abstract: Magnesite is proposed to be a major oxidized carbon storage phase in the mantle due to its wide P-T range of stability [1-2]. The presence of magnesite in the Earth's interior will depend on the redox state of the Earth's interior. Large part of the deep mantel is considered to be significantly reduced with considerable amount of FeO dispersed in rocks [3]. During slab-mantle interaction, subducted carbonates in the slab will undergo redox reactions with metallic Fe. However, the mechanism of this interaction is not well understood. In order to understand diamond genesis during the slabmantle interactions, we have conducted high-pressure and high-temperature experiments in a 2000-ton multi-anvil highpressure press on samples containing MgCO3 and iron foils (50 ?m thick) in BN capsules. The samples under pressures from 10 to 16 GPa were heated to 1200-1700 K. The samples were quenched under pressure and the quenched samples were polished and then analyzed with multi-wavelength micro-Raman spectrometers using 785, 514.5 and 532 nm laser excitations. Micro-Raman investigations show that the iron foils reduce MgCO3 to various sp2 carbon phases, mainly graphite, followed by the transformation to diamond upon long-duration heating. The transformation to diamond is driven by the temperature. For example, in the Run number PL066 with staring material containing magnesite and two Fe foils heated to 1400 K at 10 GPa for 24 hrs, and quenched, the run products were [Mg,Fe]O, and diamond and graphite. The sample PL044 with staring material containing magnesite and three Fe foils heated to 1600 K at 14 GPa for 12 hrs, the run products were larger size (~10 ?m) diamonds, iron carbide and small amount of graphite. Our results indicate that in slow subduction (T~1500 K) all carbonates will be converted in diamond and iron carbide. Under rapid subduction of the slab, the carbonate will survive and be carried to greater depth. The inclusions of [Mg,Fe]O in diamonds, however, do not necessarily indicate that this phase is of lower mantle origin.
DS201906-1340
2019
Gao, J.Qiao, X., Zhou, Z., Schwarz, D.T., Qi, L., Gao, J., Nong, P., Lai, M., Guo, K., Li, Y.Study of the differences in infrared spectra of emerald from different mining areas and the controlling factors.The Canadian Mineralogist, Vol. 57, pp. 65-79.Globalemerald genesis

Abstract: Natural emeralds from 11 mining areas were studied using an infrared spectrometer. The results showed different spectroscopic characteristics for emerald from different mine regions. Infrared absorption is mainly attributed to the vibration of Si-O lattice, channel water, alkaline cations, and molecules such as CO2, [Fe2(OH)4]2+, etc. Both near-infrared and mid-infrared spectra showed that the differences in band positions, intensities, and shapes are related to the mixed ratio of the two types of channel water. Accordingly, emerald and its mining regions can be divided into 3 types: H2O I, H2O II, and transition I-II. Furthermore, the study indicates that the relative amounts of the two different orientations of channel water molecules are mainly affected by the presence of (Mg + Fe)2+ in the host rock or in the mineralizing fluid. Therefore, the mineralization environment type (alkali-poor, alkali-rich, and transitional types) of emerald can be preliminarily identified from IR spectroscopy. This can be useful for determining the origin of emeralds.
DS202109-1495
2021
Gao, J.Xu, C., Inoue, T., Kakizawa, S., Noda, M., Gao, J.Effect of Al on the stability of dense hydrous magnesium silicate phases to the uppermost lower mantle: implications for water transportation into the deep mantle.Physics and Chemistry of Minerals, Vol. 48, 31, 10p. PdfMantlewater

Abstract: We have systematically investigated the high-pressure and high-temperature stability of Al-bearing dense hydrous magnesium silicate phases (DHMSs) in natural chlorite compositions containing?~?16 wt% H2O and?~?14 wt% Al2O3 between 14 and 25 GPa at 800-1600 °C by an MA8-type multi-anvil apparatus. A chemical mixture similar to Fe-free chlorite was also investigated for comparison. Following the pressure-temperature (P-T) path of cold subduction, the phase assemblage of phase E?+?phase D is stable at 14-25 GPa. Superhydrous phase B is observed between 16 and 22 GPa coexisting with phase E?+?phase D. Following the P-T path of hot subduction, the phase assemblage of phase E?+?garnet is identified at 14-18 GPa coexisting with the melt. The phase assemblage of superhydrous phase B?+?phase D was found at 18-25 GPa, which is expected to survive at higher P-T conditions. We have confirmed that the presence of Al could enhance the stability of DHMSs. Our results indicate that, after chlorite decomposition at the shallow region of the subduction zone, the wide stability field of Al-bearing DHMSs can increase the possibility of water transportation into the deep lower mantle.
DS202111-1792
2021
Gao, J.Xu, C., Kakizawa, S., Greaux, S., Inoue, T., Li, Y., Gao, J.Al partitioning between phase D and bridgmanite at the uppermost lower mantle.Physics and Chemistry of Minerals, Vol. 48, 10, 6p. Pdf s00269-021-Q1163-5Mantlebridgmanite

Abstract: Phase D is proposed to be the most important hydrous phase at the upper part of the lower mantle, and it has been shown to coexist with bridgmanite (Brg), the most abundant mineral and main host for Al2O3 in the lower mantle. The concentration of Al in Phase D could significantly increase the thermal stability field of Phase D, therefore, partitioning of Al between Brg and Phase D is of particular importance to constrain water distribution in the deep mantle. Here, we performed high P-T experiments in MgO-Al2O3-SiO2-H2O system to investigate the partitioning of Al between Brg and Phase D up to 32 GPa and 1350 °C. Our results indicated that Al distributes strongly into Phase D relative to Brg and the partition coefficient slightly decreases with increasing temperature. Al-bearing Phase D exhibits a very high thermal stability region, but it completely decomposed around 28 GPa and 1350 °C, at which point Brg coexisted with a large amount of melt. The depth?~?850 km (28 GPa) is thus proposed to be the second choke point for hydrous minerals. This may shed new lights on several important geophysical observations in subduction zones.
DS202204-0545
2022
Gao, J.Xu, C., Inoue, T., Gao, J., Noda, M., Kakizawa, S.Melting phase relation of Fe-bearing phase D up to the uppermost lower mantle.American Mineralogist, Vol. 107, 19p.Mantlemelting

Abstract: Dense hydrous magnesium silicates (DHMSs) are considered important water carriers in the deep Earth. Due to the significant effect of Fe on the stability of DHMSs, Fe-bearing Phase D (PhD) deserves much attention. However, few experiments have been conducted to determine the stability of PhD in different bulk compositions. In this study, we provide experimental constraints for the stability of PhD in the AlOOH-FeOOH-Mg1.11Si1.89O6H2.22 system between 18 and 25 GPa at 1000-1600 °C, corresponding to the P-T conditions of the mantle transition zone and uppermost lower mantle. Fe3+-bearing PhD was synthesized from the FeOOH-Mg1.11Si1.89O6H2.22 binary system with two different Fe3+ contents. The resultant Al,Fe3+-bearing compositions are close to analog specimens of the fully oxidized mid-ocean ridge basalt (MORB) and pyrolite in the AlOOH-FeOOH-Mg1.11Si1.89O6H2.22 ternary system. The substitution mechanism of Fe is shown to be dependent on pressure, and Fe3+ occupies both Mg and Si sites in PhD at pressures below 21 GPa. In contrast, Fe3+ only occupies Si site at pressures exceeding 21 GPa. The presence of Fe3+ results in a slight reduction in the thermal stability field of PhD in the FeOOH-Mg1.11Si1.89O6H2.22 system in comparison to Mg-bearing, Fe-free PhD. In contrast, Al,Fe3+-bearing PhD is more stable than Mg-bearing PhD in both MORB and pyrolite compositions. In this regard, Al,Fe3+-bearing PhD could act as a long-term water reservoir during subduction processes to the deep mantle.
DS202107-1098
2021
Gao, J.F.Gao, L-G., Chen, Y-W., Bi, X-W., Gao, J.F., Chen, W.T., Dong, S-H., Luo, J-C., Hu, R-Z.Genesis of carbonatite and associated U-Nb-REE mineralization at Huayang-chuan, central China: insights from mineral paragenesis, chemical and Sr-Nd-C-O isotopic compositions of calcite.Ore Geology Reviews, doi.org/10.1016/j.oregeorev.2021.104310, 50p. PdfChinacarbonatite, REE

Abstract: The Huayangchuan deposit in the North Qinling alkaline province of Central China is a unique carbonatite-hosted giant U-Nb-REE polymetallic deposit. The mineralization is characterized by the presence of betafite, monazite, and allanite as the main ore minerals, but also exhibit relatively high budgets of heavy rare earth elements (HREE = Gd-Lu and Y). The origin of carbonatites has long been controversial, thus hindering our understanding of the genesis of the deposit. Here, we conducted an in-situ trace elemental, Sr-Nd isotopic, and bulk C-O isotopic analyses of multi-type calcites in the deposit. Two principal types (Cal-I and Cal-II), including three sub-types (Cal-I-1, Cal-I-2 and Cal-I-3) of calcites were identified based on crosscutting relationships and calcite textures. Texturally, Cal-I calcites in carbonatites display cumulates with the grain size decreasing from early coarse- (Cal-I-1) to medium- (Cal-I-2) and late fine-grained (Cal-I-3), whereas Cal-II calcites coexist with zeolite displaying zeolite-calcite veinlets. Geochemically, Cal-I calcites contain relatively high REE(Y) (151-2296 ppm), Sr (4947-9566 ppm) and Na (28.6-390 ppm) contents, characterized by right- to left-inclined flat distribution patterns [(La/Yb)N=0.2-4.2] with enrichment of HREE(Y) (136-774 ppm), whereas Cal-II calcites display low REE, Sr and undetectable Na contents, characterized by a right-inclined distribution pattern [(La/Yb)N=13.5, n=16]. The U-Nb-REE mineralization, accompanied with intense and extensive fenitization and biotitization, is mainly associated with the Cal-I-3 calcites which show flat to relatively left-inclined flat REE distribution patterns [(La/Yb)N=0.2-1.0]. Isotopic results show that Cal-I calcites with mantle signatures are primarily igneous in origin, whereas Cal-II are hydrothermal, postdating the U-Nb-REE mineralization. Cal-I calcites (Cal-I-1, Cal-I-2 and Cal-I-3) from mineralized and unmineralized carbonatites, displayed regular changes in REE, Na and Sr contents, but similar trace element distribution patterns and Sr-Nd-C-O isotopic signatures, indicating that these carbonatites originated from the same enriched mantle (EM1) source by low-degree partial melting of HREE-rich carbonated eclogites related to recycled marine sediments. The combination of trace elements and Sr-Nd isotopic composition of calcites further revealed that these carbonatites have undergone highly differentiated evolution. Such differentiation is conducive to the enrichment of ore-forming elements (U-Nb-REE) in the late magmatic-hydrothermal stages owing to extensive ore-forming fluids exsolved from carbonatitic melts. The massive precipitation of the U-Nb-REE minerals from ore-forming hydrothermal fluids may have been triggered by intense fluid-rock reactions indicated by extensive and intense fenitization and biotitization. Therefore, the Huayangchuan carbonatite-related U-Nb-REE deposit may have formed by a combination of processes involving recycled U-Nb-REE-rich marine sediments in the source, differentiation of the produced carbonatitic magmas, and subsequent exsolution of U-Nb-REE-rich fluids that precipitated ore minerals through reactions with wall rocks under the transitional tectonic regime from compression to extension at the end of Late Triassic.
DS202108-1289
2021
Gao, L.Hu, Z., Zeng, L., Foerster, M.W., Li, S., Zhao, L., Gao, L., Li, H., Yang, Y.Recycling of subducted continental crust: geochemical evidence from syn-exhumation Triassic alkaline mafic rocks of the southern Liaodong Peninsula, China.Lithos, 10.1016/j.lithos.2021.106353 13p. Chinaalkaline rocks

Abstract: Syn-exhumation mafic magmatism during continental collision provides insights into the crust-mantle reaction during deep subduction and the nature of orogenic lithospheric mantle in collisional orogens. In this study, we present a comprehensive data set of zircon U-Pb ages and whole-rock major-trace elements as well as Sr-Nd-Pb isotopes of alkaline mafic rocks from the southern Liaodong Peninsula, eastern China. Zircon U-Pb analyses yield Late Triassic age of 213 ± 3 to 217 ± 3 Ma, younger than the Middle Triassic ultrahigh-pressure metamorphic rocks of the Dabie-Sulu orogen. Thus, the alkaline mafic rocks are products of syn-exhumation magmatism during continental collision of the South and North China blocks. The rocks show shoshonitic affinities with high K2O (3.78-5.23 wt%) and K2O/Na2O (0.71-1.22). They are characterized by arc-like trace-element patterns with enriched LILE, Pb, and LREE, and depleted HFSE. They exhibit enriched Sr-Nd isotopic compositions with high initial 87Sr/86Sr isotopic ratios of 0.7058-0.7061 and negative ?Nd(t) values of ?13.0 to ?15.1. These results suggest involvement of recycled continental crust in their mantle source. The mantle source likely formed by the metasomatic reaction of subducted continental crust-derived melts with the overlying subcontinental lithospheric mantle during the Triassic continental collision. Decompressional melting of this metasomatized mantle formed syn-exhumation mafic magmas during the transition from convergent to extensional tectonics in the Late Triassic. Accordingly, mafic rocks from the southern Liaodong Peninsula provide a geochemical record of the subduction and recycling of continental crust into the mantle and melt-mantle reaction induced metasomatism within the orogen.
DS202107-1098
2021
Gao, L-G.Gao, L-G., Chen, Y-W., Bi, X-W., Gao, J.F., Chen, W.T., Dong, S-H., Luo, J-C., Hu, R-Z.Genesis of carbonatite and associated U-Nb-REE mineralization at Huayang-chuan, central China: insights from mineral paragenesis, chemical and Sr-Nd-C-O isotopic compositions of calcite.Ore Geology Reviews, doi.org/10.1016/j.oregeorev.2021.104310, 50p. PdfChinacarbonatite, REE

Abstract: The Huayangchuan deposit in the North Qinling alkaline province of Central China is a unique carbonatite-hosted giant U-Nb-REE polymetallic deposit. The mineralization is characterized by the presence of betafite, monazite, and allanite as the main ore minerals, but also exhibit relatively high budgets of heavy rare earth elements (HREE = Gd-Lu and Y). The origin of carbonatites has long been controversial, thus hindering our understanding of the genesis of the deposit. Here, we conducted an in-situ trace elemental, Sr-Nd isotopic, and bulk C-O isotopic analyses of multi-type calcites in the deposit. Two principal types (Cal-I and Cal-II), including three sub-types (Cal-I-1, Cal-I-2 and Cal-I-3) of calcites were identified based on crosscutting relationships and calcite textures. Texturally, Cal-I calcites in carbonatites display cumulates with the grain size decreasing from early coarse- (Cal-I-1) to medium- (Cal-I-2) and late fine-grained (Cal-I-3), whereas Cal-II calcites coexist with zeolite displaying zeolite-calcite veinlets. Geochemically, Cal-I calcites contain relatively high REE(Y) (151-2296 ppm), Sr (4947-9566 ppm) and Na (28.6-390 ppm) contents, characterized by right- to left-inclined flat distribution patterns [(La/Yb)N=0.2-4.2] with enrichment of HREE(Y) (136-774 ppm), whereas Cal-II calcites display low REE, Sr and undetectable Na contents, characterized by a right-inclined distribution pattern [(La/Yb)N=13.5, n=16]. The U-Nb-REE mineralization, accompanied with intense and extensive fenitization and biotitization, is mainly associated with the Cal-I-3 calcites which show flat to relatively left-inclined flat REE distribution patterns [(La/Yb)N=0.2-1.0]. Isotopic results show that Cal-I calcites with mantle signatures are primarily igneous in origin, whereas Cal-II are hydrothermal, postdating the U-Nb-REE mineralization. Cal-I calcites (Cal-I-1, Cal-I-2 and Cal-I-3) from mineralized and unmineralized carbonatites, displayed regular changes in REE, Na and Sr contents, but similar trace element distribution patterns and Sr-Nd-C-O isotopic signatures, indicating that these carbonatites originated from the same enriched mantle (EM1) source by low-degree partial melting of HREE-rich carbonated eclogites related to recycled marine sediments. The combination of trace elements and Sr-Nd isotopic composition of calcites further revealed that these carbonatites have undergone highly differentiated evolution. Such differentiation is conducive to the enrichment of ore-forming elements (U-Nb-REE) in the late magmatic-hydrothermal stages owing to extensive ore-forming fluids exsolved from carbonatitic melts. The massive precipitation of the U-Nb-REE minerals from ore-forming hydrothermal fluids may have been triggered by intense fluid-rock reactions indicated by extensive and intense fenitization and biotitization. Therefore, the Huayangchuan carbonatite-related U-Nb-REE deposit may have formed by a combination of processes involving recycled U-Nb-REE-rich marine sediments in the source, differentiation of the produced carbonatitic magmas, and subsequent exsolution of U-Nb-REE-rich fluids that precipitated ore minerals through reactions with wall rocks under the transitional tectonic regime from compression to extension at the end of Late Triassic.
DS1998-1300
1998
Gao, R.Schulze, A., Jiang, M., Ryberg, T., Gao, R.Survey yields dat a on unique metamorphic rock complex in ChinaEos, Vol. 79, No. 36, Sept. 8, p. 429, 433.ChinaGeophysics - seismics, Dabie Shan
DS2001-0684
2001
Gao, R.Li, P., Cui, J., Gao, R.Estimation of shortening between Siberian and Indian plates since the Early CretaceousJour. Asian Earth Sci., Vol. 20, No. 3, pp. 241-5.Russia, Siberia, IndiaTectonics - compression Himalayan Block
DS200512-0242
2005
Gao, R.Dong, S., Gao, R., Cong, B., Zhao, Z., Liu, X., Li, S., Huang, D.Crustal structure of the southern Dabie ultrahigh pressure orogen and Yangtze foreland from deep seismic reflection profiling.Terra Nova, Vol. 16, 6, Dec. pp. 319-324.ChinaUHP, tectonics
DS200812-0290
2008
Gao, R.Dong, S.W., Li, Q.S., Gao, R., Liu, F.T., Liu, X.C., Xue, H.M., Guan, Y.Moho mapping in the Dabie ultrahigh pressure collisional orogen, central China.American Journal of Science, Vol. 308, 4, pp. 517-528.ChinaUHP
DS1995-0579
1995
Gao, S.Gao, S., Wedepohl, K.H.The negative Eu anomaly in Archean sedimentary rocks: implications fordecomposition, age, importance graniteEarth and Planet. Science Letters, Vol. 133, pp. 81-94South Africa, Greenland, North America, Australia, ChinaArchean Eu signatures, Europium, Continental crust composition
DS1995-0580
1995
Gao, S.Gao, S., Zhang, B.R., Guo, X-M.Silurian Devonian provenance changes of South Qinling Basins: implicationfor accretion of Yangtze craton.Tectonophysics, Vol. 250, No. 1/3, Nov. 15, pp. 183-ChinaCraton, North China
DS1998-0465
1998
Gao, S.Gao, S., Zhang, B.R., Zhao, Z.D.How mafic is the lower continental crust?Earth and Planetary Science Letters, Vol. 161, No. 1-4, Sept. 1, pp. 101-118.MantleMagmatism
DS1999-0358
1999
Gao, S.Kern, H., Gao, S., Jin, S.Petrophysical studies on rocks from the Dabie ultrahigh pressure metamorphic belt: implications for compositionTectonophysics, Vol. 301, No. 3-4, Jan. 30, pp. 191-216.ChinaCrust - petrology, metamorphism
DS2000-0310
2000
Gao, S.Gao, S., Kern, H., Zhao, Z-B.Measured and calculated seismic velocities and densities for granulites from xenolith occurrencesJournal of Geophysical Research, Vol. 105, No.8, Aug. 10, pp.18965-76.ChinaCraton - North, Lower crustal sections
DS2001-0355
2001
Gao, S.Gao, S., Kern, H., Jin, Popp, Jin, Zhang, ZhangPoisson's ratio of eclogite: the role of retrogressionEarth and Planetary Science Letters, Vol. 192, No. 4, pp. 523-31.GlobalEclogite - geochemistry, Poisson ratio
DS2001-1076
2001
Gao, S.Silver, P., Gao, S.Anisotropic and discontinuity structure beneath southern AfricaSlave-Kaapvaal Workshop, Sept. Ottawa, 1p. abstractSouth AfricaGeophysics - seismics
DS2002-0087
2002
Gao, S.Ayers, J.C., Dunkle, S., Gao, S., Miller, C.F.Constraints on timing of peak and retrograde metamorphism in the Dabie Shan ultrahigh pressure metamorphic belt, east central China, using U Th PbChemical Geology, Vol.186,2-3, pp.315-31.ChinaUHP, Geochronology - dating of zircon and monazite
DS2002-0497
2002
Gao, S.Gao, S., Rudnick, R.L., Carlson, R.W., McDonough, LiuRe-Os evidence for replacement of ancient mantle lithosphere beneath the North Chin a Craton.Earth and Planetary Science Letters, Vol.198,3-4,pp. 307-22., Vol.198,3-4,pp. 307-22.ChinaGeochronology, Craton - North China
DS2002-0498
2002
Gao, S.Gao, S., Rudnick, R.L., Carlson, R.W., McDonough, LiuRe-Os evidence for replacement of ancient mantle lithosphere beneath the North Chin a Craton.Earth and Planetary Science Letters, Vol.198,3-4,pp. 307-22., Vol.198,3-4,pp. 307-22.ChinaGeochronology, Craton - North China
DS2002-1773
2002
Gao, S.Zhang, H., Gao, S., Zhong, Z., Zhang, B., Zhang, L., Hu, S.Geochemical and Sr Nd Pb isotopic compositions of Cretaceous granitoids: constraintsChemical Geology, Vol. 186, 2-4, pp. 281-99.China, easternUHP, Dabie Shan area
DS2003-0820
2003
Gao, S.Ling, W., Gao, S., Zhang, B., Li, H., Liu, Y., Cheng, J.Neoproterozoic tectonic evolution of the northwestern Yangtze Craton, South China:Precambrian Research, Vol. 122, 1-4, pp.111-140.China, RodiniaTectonics
DS200412-0605
2003
Gao, S.Gao, S., Rudnick, R.L., Carlson, R.W.Removal of lithospheric mantle in the North Chin a Craton: Re Os isotopic evidence for coupled crust - mantle growth.Earth Science Frontiers, Vol. 10, 3, pp. 61-68. Ingenta 1035303167ChinaGeochronology
DS200412-1139
2003
Gao, S.Ling, W., Gao, S., Zhang, B., Li, H., Liu, Y., Cheng, J.Neoproterozoic tectonic evolution of the northwestern Yangtze Craton, South China: implications for amalgamation and break up ofPrecambrian Research, Vol. 122, 1-4, pp.111-140.China, RodiniaTectonics
DS200412-1164
2003
Gao, S.Liu, Y.,Gao, S., Liu, X., Chen, X., Zheng, W., Wang, X.Thermodynamic evolution of lithosphere of the North Chin a Craton: records from lower crust and upper mantle xenoliths from HannuChinese Science Bulletin, Vol. 48, 21, pp. 2371-77. Ingenta 1035395020ChinaGeothermometry
DS200412-1165
2004
Gao, S.Liu, Y., Gao, S., Yuan, H., Zhou, L., Liu, X., Wang, X., Hu, Z., Wang, L.U Pb zircon ages and Nd, Sr, and Pb isotopes of lower crustal xenoliths from North Chin a Craton: insights on evolution of lowerChemical Geology, Vol. 211, 1-2, Nov. 8, pp. 87-109.ChinaGeochronology
DS200412-1700
2004
Gao, S.Rudnick, R.L., Gao, S., Ling, W-I., Liu, Y-S., McDonough, W.F.Petrology and geochemistry of spinel peridotite xenoliths from Hannuoba and Qixia, North Chin a Craton.Lithos, Vol. 77, 1-4, Sept. pp. 609-637.ChinaArchean craton, geochemistry, major, trace, thermometry
DS200512-0313
2004
Gao, S.Gao, S., Rudnick, R.L., Yuan, H.L., Liu, X.M., Liu, Y.S., Xu, W.L., Ling, W.L., Ayers, K., Wang, X.C.,Wang, Q.H.Recycling lower continental crust in the North Chin a Craton.Nature, No. 7019, Dec. 16, pp. 892-896.ChinaSubduction
DS200512-0651
2005
Gao, S.Liu, Y., Gao, S., Lee, C.T.A., Hu, S., Liu, X.,Yuan, H.Melt peridotite interactions: links between garnet pyroxenite and high Mg# signature of continental crust.Earth and Planetary Science Letters, Vol. 234, pp. 39-57.MantleGeochemistry
DS200512-1078
2004
Gao, S.Teng, F.Z., McDonough, W.F., Rudnick, R.L., Dalpe, C., Tomascak, P.B., Chappell, B.W., Gao, S.Lithium isotopic composition and concentration of the upper continental crust.Geochimica et Cosmochimica Acta, Vol. 68, 20, pp. 4167-4178.MantleGeochemistry, geochronology
DS200612-0106
2006
Gao, S.Becker, H., Horan, M.F., Walker, R.J., Gao, S., Lorand, J-P., Rudnick, R.L.Highly siderophile element composition of the Earth's primitive upper mantle: constraints from new dat a on peridotite massifs and xenoliths.Geochimica et Cosmochimica Acta, Vol. 70, 17, pp. 4528-4550.MantleMineral chemistry
DS200612-0428
2006
Gao, S.Gao, S., Rudnick, R.L., Xu, W.L., Yuan, H.L., Hu, Z.C., Liu, X.M.Lithospheric evolution of the North Chin a Craton: evidence from high Mg adakitic rocks and their entrained xenoliths.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 193, abstract only.ChinaGeochemistry
DS200612-0830
2006
Gao, S.Liu, X., Gao, S., Ling, W., Yuan, H., Hu, Z.Identification of 3.5 Ga detrital zircons from Yangtze Craton in South Chin a and the implication for Archean crust evolution.Progress in Natural Science, Vol. 16, 6, June pp. 663-666.ChinaGeochronology
DS200612-1579
2006
Gao, S.Yuan, H.L., Gao, S., Rudnick, R.L., Jin, Z.M., Walker, R.J.Re Os evidence for age and origin of peridotites from the Dabie Sulu UHP belt.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 10. abstract only.ChinaUHP, geochronology
DS200612-1594
2006
Gao, S.Zhang, S-B., Zheng, Y-F., Wu, Y-B., Zhao, Z-F., Gao, S., Wu, F-Y.Zircon isotope evidence for >3.5 Ga continental crust in the Yangtze craton of China.Precambrian Research, in press,ChinaCrustal evolution, geochronology
DS200712-0347
2007
Gao, S.Gao, S., Rudnick, R.L., Xu, W-L., Yuan, Liu, Puchtel, Liu, Huang, WangRecycling deep cratonic lithosphere and generation of intraplate magmatism.Plates, Plumes, and Paradigms, 1p. abstract p. A307.ChinaAlkaline rocks, picrites
DS200712-1184
2007
Gao, S.Wu, Y-B., Gao, S., Zhang, H-F., Wang, S-H., Jiao, W-F., Liu, Y-S, Yuan, H-L.Timing of UHP metamorphism in the Hongan area, western Dabie Mountains China: evidence from zircon Pb age, trace element and Hf isotope composition.Contributions to Mineralogy and Petrology, Vol. 155, 1, pp. 123-133.ChinaUHP
DS200812-0385
2008
Gao, S.Gao, S., Rudnick, R.L., Xu, Yuan, Liu, Walker, Puchtel, Liu, Huang, Wang, WangRecycling deep cratonic lithosphere and generation of intraplate magmatism in the North Chin a Craton.Earth and Planetary Science Letters, Vol. 270, 1-2, June 15, pp. 41-53.ChinaTectonics - delamination, picrites
DS200812-0487
2008
Gao, S.Hu, Z., Gao, S.Upper crustal abundances of trace elements: a revision and update.Chemical Geology, Vol. 253, 3-4, August 15, pp. 205-221.MantleSediments - not specific to diamonds
DS200812-0678
2008
Gao, S.Liu, X., Gao, S., Diwu, C., Ling, W.Precambrian crustal growth of Yangtze Craton as revealed by detrital zircon studies.American Journal of Science, Vol. 308, 4, pp. 421-468.ChinaGeochronology
DS200812-0680
2008
Gao, S.Liu, Y., Gao, S., Gao, C., Zong, K.Recycling of lower continental crust in the Trans-North Chin a Orogen: evidence from zircon dating of mantle composite xenoliths.Goldschmidt Conference 2008, Abstract p.A563.ChinaCraton
DS200812-1162
2008
Gao, S.Teng, F-Z., Rudnick, R.L., McDonough, W.F., Gao, S., Tomascal, P.B., Liu, Y.Lithium isotopic composition and concentration of the deep continental crust.Chemical Geology, Vol. 255, 1-2, Sept. 30, pp. 47-59.MantleGeochronology
DS200812-1282
2008
Gao, S.Xu, W-L., Yang, D.B., Gao, S., Yu, Y., Pei, F.P.Mesozoic lithospheric mantle of the Central North Chin a craton: evidence from peridotite xenoliths.Goldschmidt Conference 2008, Abstract p.A1047.ChinaXenoliths
DS201012-0453
2010
Gao, S.Liu, J., Rudnick, R., Walker, R., Gao, S., Wu, F., Xu, W., Xu, Y.OS isotope evidence for diachronous formation of lithospheric mantle beneath the Trans-North Chin a oorgen, north Chin a, craton.Goldschmidt 2010 abstracts, abstractChinaGeochronology
DS201012-0828
2010
Gao, S.Wang, C., Jin, Z., Gao, S., Zhang, J., Zheng, S.Eclogite- melt/peridotite reaction: experimental constraints of the destruction mechanism of the North Chin a craton.Science China Earth Sciences, Vol. 53, 6, pp. 797-809.ChinaMelting
DS201112-0611
2011
Gao, S.Liu, J., Rudnick, R.L., Walker, R.J., Gao, S., Wu, F-y., Piccoli, P.M., Yuan, H., Xu, W-l., Xu, Yi-G.Mapping lithospheric boundaries using Os isotopes of mantle xenoliths: an example from the North Chin a Craton.Geochimica et Cosmochimica Acta, Vol. 75, 13, pp. 3881-3902.ChinaGeochronology
DS201112-1099
2011
Gao, S.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
DS201112-1123
2011
Gao, S.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
Gao, S.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
Gao, S.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
DS201112-1129
2011
Gao, S.Xu,L., Zhou, Q.J., Pei, F.P., Yang, D.B., Gao, S., Wang, W., Feng, H.Recycling lower continental crust in an intra continental setting: mineral chemistry and oxygen isotope insights from websterite xenoliths.Goldschmidt Conference 2011, abstract p.2197.ChinaNorth China craton
DS201212-0797
2013
Gao, S.Xu, W-L., Zhou, Q-J., Pei, F-P., Gao, S., Li, Q-L., Yang, Y-H.Destructive of the North Chin a craton: delamin ation or thermal/chemical erosion? Mineral chemistry and oxygen isotope insights from websterite xenoliths.Gondwana Research, Vol. 23, 1, pp. 119-129.ChinaCraton, destruction
DS201412-0960
2014
Gao, S.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
DS201603-0419
2016
Gao, S.Shang, R., Chen, S., Wang, B-W., Wang, Z-M., Gao, S.Temperature induced irreversible phase transition from perovskite to diamond but pressure-driven back-transition in an ammonium copper formate.Angewandte Chemie, Vol. 18. 6. pp. 2137-2140.TechnologyPerovskite

Abstract: The compound [CH3 CH2 NH3 ][Cu(HCOO)3 ] undergoes a phase transition at 357 K, from a perovskite to a diamond structure, by heating. The backward transition can be driven by pressure at room temperature but not cooling under ambient or lower pressure. The rearrangement of one long copper-formate bond, the switch of bridging-chelating mode of the formate, the alternation of N-H???O H-bonds, and the flipping of ethylammonium are involved in the transition. The strong N-H???O H-bonding probably locks the metastable diamond phase. The two phases display magnetic and electric orderings of different characters.
DS201603-0432
2016
Gao, S.Yang, W., Teng, F-Z., Li, W-Y., Liu, S-A., Ke, S., Liu, Y-S., Zhang, H-F., Gao, S.Magnesium isotopic composition of the deep continental crust.American Mineralogist, Vol. 101, pp. 243-252.MantleMineralogy
DS201605-0838
2016
Gao, S.Gaschnig, R.M., Rudnick, R.L., McDonough, W.F., Kaufman, A.J., Valley, J., Hu, Z., Gao, S., Beck, M.L.Compositional evolution of the upper continental crust through time, as constrained by ancient glacial diamictites.Geochimica et Cosmochimica Acta, in press available 78p.MantleBulk chemistry

Abstract: The composition of the fine-grained matrix of glacial diamictites from the Mesoarchean, Paleoproterozoic, Neoproterozoic, and Paleozoic, collected from four modern continents, reflect the secular evolution of the average composition of the upper continental crust (UCC). The effects of localized provenance are present in some cases, but distinctive geochemical signatures exist in diamictites of the same age from different localities, suggesting that these are global signatures. Archean UCC, dominated by greenstone basalts and less so komatiites, was more mafic, based on major elements and transition metal trace elements. Temporal changes in oxygen isotope ratios, rare earth elements, and high field strength elements indicate that the UCC became more differentiated and that tonalite-trondhjemite-granodiorite suites became less important with time, findings consistent with previous studies. We also document the concentrations of siderophile and chalcophile elements (Ga, Ge, Cd, In, Sn, Sb, W, Tl, Bi) and lithophile Be in the UCC through time, and use the data for the younger diamictites to construct a new estimate of average UCC along with associated uncertainties.
DS201701-0040
2017
Gao, S.Zhang, J., Liu, Y-S., Ling, W., Gao, S.Pressure dependent compatibility of iron in garnet: insights into the proigin of ferropicrite melt mantle, China.Geochimica et Cosmochimica Acta, Vol. 197, pp. 356-377.ChinaPicrite

Abstract: Iron-rich silicate melts in the Earth’s deep mantle have been seismologically and geochemically inferred in recent years. The origin of local enrichments in iron and low-velocity seismic anomalies that have been detected in dense mantle domains are critical to understanding the mantle’s evolution, which has been canonically explained by long-term chemical reactions between the Earth’s silicate mantle and its liquid iron outer core. However, the Pleistocene alkaline ferropicrites (?0.73 Ma) from Wudi, North China, show chemical and Sr-Nd-Os isotopic features that suggest derivation from the preferential melting of silica-deficient eclogite, a lithology of delaminated mafic lower continental crust that had stagnated at mid-upper mantle depths during the Mesozoic decratonization of the North China block. These rocks are characterized by substantial enrichment in iron (14.9-15.2 wt% Fe2O3), relative depletion in silica (40-41 wt% SiO2) and decoupled Y and heavy rare earth element (HREE) compositions. These ferropicrites have particularly higher Y/Yb ratios than the other Cenozoic basalts from North China. The pressure-dependent compatibility of Fe, Y and Yb in eclogitic garnet can adequately explain the Fe-enrichment and Y-HREE decoupling of the Wudi ferropicrites and indicates that the eclogites were melted at pressures of 5-8 GPa, as also constrained by previous high-P-T experiments. This melting depth ties together a seismically imaged high-velocity anomaly that extends from 150 km to 350 km in depth under the study area, which has been commonly interpreted as evidence for the stagnation of the missing, delaminated continental lithosphere. Our findings provide an alternative mechanism to produce an extremely iron-rich mantle reservoir in addition to core-mantle interaction. Iron-rich silicate melts that form by this process are likely to be denser than the ambient mantle peridotite (and therefore drive flow downward) and may play a more significant role in the deep-mantle geophysical and geochemical diversities than previously considered.
DS201703-0406
2017
Gao, S.He, D., Liu, Y., Gao, C., Chen, C., Hu, Z., Gao, S.SiC dominated ultra-reduced mineral assemblage in carbonatitic xenoliths from the Dalihu basalt, Inner Mongolia, China.American Mineralogist, Vol. 102, pp. 312-320.China, MongoliaCarbonatite

Abstract: SiC and associated ultra-reduced minerals were reported in various geological settings, however, their genesis and preservation mechanism are poorly understood. Here, we reported a SiC-dominated ultra-reduced mineral assemblage, including SiC, TiC, native metals (Si, Fe, and Ni) and iron silicide, from carbonatitic xenoliths in Dalihu, Inner Mongolia. All minerals were identified in situ in polished/thin sections. SiC is 20-50 ?m in size, blue to colorless in color, and usually identified in the micro-cavities within the carbonatitic xenolith. Four types of SiC polytypes were identified, which are dominated by ?-SiC (3C polytype) and 4H polytype followed by 15R and 6H. These SiC are featured by 13C-depleted isotopic compositions (?13C = ?13.2 to ?22.8‰, average = ?17.7‰) with obvious spatial variation. We provided a numerical modeling method to prove that the C isotopic composition of the Dalihu SiC can be well-yielded by degassing. Our modeling results showed that degassing reaction between graphite and silicate can readily produce the low ?13C value of SiC, and the spatial variations in C isotopic composition could have been formed in the progressive growth process of SiC. The detailed in situ occurring information is beneficial for our understanding of the preservation mechanism of the Dalihu ultra-reduced phase. The predominant occurrence of SiC in micro-cavities implies that exsolution and filling of CO2 and/or CO in the micro-cavities during the diapir rising process of carbonatitic melt could have buffered the reducing environment and separated SiC from the surrounding oxidizing phases. The fast cooling of host rock, which would leave insufficient time for the complete elimination of SiC, could have also contributed to the preservation of SiC.
DS202201-0015
2021
Gao, S.Gao, S., Campbell, K., Flemming, R., Kupsch, B., Armstrong, K.Characterizing zinc-bearing chromite cores in uvarovite garnets from the Pikoo diamondiferous kimberlite field, central eastern Saskatchewan, Canada.GAC/MAC Meeting UWO, 1p. Abstract p. 100.Canada, Saskatchewandeposit - Pikoo

Abstract: Zinc-rich chromite [(Fe,Zn)Cr2O4] is an important repository for chromium (Cr) that has been observed sporadically in kimberlite-bearing deposits worldwide. As another source reservoir for Cr, the green uvarovite garnet [ideally Ca3Cr2(SiO4)3] is the rarest variety among anhydrous garnets. Despite being reported from a wide range of localities, the occurrences of uvarovite are predominately restricted to hydrothermal and metamorphic settings rarely associated with kimberlite. Here, we present a detailed petrographic, mineralogical, and geochemical characterization of 71 uvarovite garnets with zinc-bearing chromite cores recovered from the Pikoo Property (central eastern Saskatchewan), which also hosts recently discovered kimberlites proven to be diamondiferous. In this work, euhedral to anhedral unzoned chromite occurs as kernels or cores and, in some cases, as irregular inclusions enclosed by uvarovite mantles. They contain moderate to high Cr [41.63-66.70 wt.% Cr2O3; Cr/(Cr+Al) = 0.64-0.99], Fe2+ (16.71-28.67 wt.% FeO) and Zn (1.64-15.52 wt.% ZnO) contents (Fig. 1), accompanied by an appreciable amount of Mn (0.63-2.32 wt.% MnO). The core with the highest Zn content gave structural formula (Zn0.409Fe2+0.555Mg0.018Mn0.019)1.00(Cr1.174Al0.674Fe3+0.152)2.00O4, which corresponds to Zn-rich chromite with a minor proportion of other end-members (e.g., hercynite, FeAl2O4). The garnets are compositionally zoned and occasionally devoid of inclusions. Formula calculations indicate that they are mainly members of the uvarovite-grossular series (up to 93% mol.% Uv) enriched in Ca (22.99-35.57 wt.% CaO) and Cr (up to 28.10 wt.% Cr2O3), but consistently depleted in Mg (mean = 0.10 wt.% MgO) and Ti (mean = 0.26 wt.% TiO2). Most garnets exhibit a core-rim zoning pattern, whereas the remainder are irregularly zoned and show evidence of resorption. The core to rim trend is characterized by an increase in grossular proportion at the expense of the uvarovite component. Morphological characteristics, textural interrelations, and compositional trends suggest that uvarovite garnet formed through interaction of Zn-rich chromite with late metasomatic (Ca,Al)-enriched hydrothermal fluids capable of precipitating secondary grossular.
DS2000-0895
2000
Gao, S.S.Silver, P.G., Gao, S.S.Mantle deformation beneath southern Africa #1Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-163.South AfricaCraton - evolution Kaapvaal, Zimbabwean, Geophysics - seismics
DS2002-0499
2002
Gao, S.S.Gao, S.S., Liu, K.H., Chen, C., Hubbard, M., Zachary, J., Zhang, Y.Old rifts never die: crustal thickening across the Midcontinent rift and its possible role in post rifting tectonics.Geological Society of America Annual Meeting Oct. 27-30, Abstract p. 79.AppalachiaTectonics - rifts
DS2002-0500
2002
Gao, S.S.Gao, S.S., Silver, P.G., Liu, K.H.Mantle discontinuities beneath southern AfricaGeophysical Research Letters, Vol. 29,10,May15,pp.129-South Africa, BotswanaGeophysics - seismics
DS2002-0958
2002
Gao, S.S.Liu, K.H., Gao, S.S.Possible seismic discontinuities in the lower mantleGeological Society of America Annual Meeting Oct. 27-30, Abstract p. 21.MantleGeophysics - seismics
DS2003-0439
2003
Gao, S.S.Gao, S.S., Liu, K.H., Davis, P.M., Slack, P.D., Zorin, Y.A., Mordvinova, V.V.Evidence for small scale mantle convection in the upper mantle beneath the Baikal RiftJournal of Geophysical Research, Vol. 108, B4, April 11, 10.1029/2002JB002039RussiaGeophysics - seismics
DS2003-0832
2003
Gao, S.S.Liu, K.H., Gao, S.S., Silver, P.G., Zhang, Y.Mantle layering across central South AmericaJournal of Geophysical Research, Vol. 108, B11, 2510 DOI. 1029/2002JB002208Brazil, South AmericaGeophysics - seismics, discontinuity, depth, Nazca, sub
DS200412-0606
2003
Gao, S.S.Gao, S.S., Liu, K.H., Davis, P.M., Slack, P.D., Zorin, Y.A., Mordvinova, V.V., Kozhevnikov, V.M.Evidence for small scale mantle convection in the upper mantle beneath the Baikal Rift zone.Journal of Geophysical Research, Vol. 108, B4, April 11, 10.1029/2002 JB002039RussiaGeophysics - seismics
DS200412-1159
2003
Gao, S.S.Liu, K.H.,Gao, S.S., Silver, P.G., Zhang, Y.Mantle layering across central South America.Journal of Geophysical Research, Vol. 108, B11, ESE 9 10.1029/2003 JB002208South America, MantleGeophysics - seismics
DS200412-1824
2004
Gao, S.S.Silver, P.G., Fouch, M.J., Gao, S.S., Schmitz, M.Seismic anisotropy, mantle fabric, and the magmatic evolution of Precambrian southern Africa.South African Journal of Geology, Vol. 107, 1/2, pp. 45-58.Africa, South AfricaGeophysics - seismics, tectonics, magmatism
DS200612-0964
2006
Gao, S.S.Nair, S.K., Gao, S.S., Liu, K.H., Silver, P.G.Southern African crustal evolution and composition: constraints from receiver function system.Journal Geophysical Research, Vol. 111, B2, Feb. 17, B02304Africa, South AfricaGeophysics - seismics
DS200712-0638
2006
Gao, S.S.Liu, K.H., Gao, S.S.Mantle transition zone discontinuities beneath the Baikal rift and adjacent areas.Journal of Geophysical Research, Vol. 111, B 11, B11301.RussiaGeophysics - seismics
DS201112-0001
2011
Gao, S.S.Abdelsalam, M.G., Gao, S.S., Liegeois, J-P.Upper mantle structure of the Sahara metacraton.Journal of African Earth Sciences, Vol. 60, 5, pp. 328-336.AfricaUpper mantle structure, convection
DS201312-0292
2014
Gao, S.S.Gao, S.S., Liu, K.H.Imaging mantle discontinuities using multiply-reflected P to S conversions.Earth and Planetary Science Letters, Vol. 402, pp. 99-106.MantleGeophysics - seismics
DS201312-0293
2013
Gao, S.S.Gao, S.S., Liu, Reed, Yu, Massinque, Mdala, Moidaki, Mutamina, Atekwana, Ingate, ReuschSeismic arrays to study African Rift initiation.EOS Transaction of AGU, Vol. 94, 24, June 11, pp. 213-214.Africa, southern AfricaGeophysics - seismics
DS201312-0738
2014
Gao, S.S.Refayee, H.A., Yang, B.B., Liu, K.H., Gao, S.S.Mantle flow and lithosphere asthenosphere coupling beneath the southwestern edge of the North American craton: constraints from shear wave splitting measurements.Earth and Planetary Science Letters, Vol. 402, pp. 209-220.CanadaAnisotropy
DS201512-1997
2015
Gao, S.S.Yu, Y., Liu, K.H., Reed, C.A., Moidaki, M., Mickus, K., Atekwana, E.A., Gao, S.S.A joint receiver function and gravity study of crustal structure beneath the incipient Okavango Rift, Botswana.Geophysical Research Letters, Vol. 42, 20, pp. 8398-8405.Africa, BotswanaGeophysics - gravity

Abstract: Rifting incorporates the fundamental processes concerning the breakup of continental lithosphere and plays a significant role in the formation and evolution of sedimentary basins. In order to decipher the characteristics of rifting at its earliest stage, we conduct the first teleseismic crustal study of one of the world's youngest continental rifts, the Okavango Rift Zone (ORZ), where the magma has not yet breached the surface. Results from receiver function stacking and gravity modeling indicate that the crust/mantle boundary beneath the ORZ is uplifted by 4-5 km, and the initiation of the ORZ is closely related to lithospheric stretching. Possible decompression melting of the subcrustal lithosphere occurs beneath the ORZ, as evidenced by a relatively low upper mantle density based on the gravity modeling.
DS201909-2106
2019
Gao, S.S.Wang, T., Gao, S.S., Dai, Y., Yang, Q., Liu, K.H.Lithospheric structure and evolution of southern Africa: constraints from joint inversion of Rayleigh wave dispersion and receiver functions.Geochemistry, Geophysics, Geosystems, Vol. 20, 7, pp. 3311-3327.Africa, South Africageophysics

Abstract: We conduct a joint inversion of teleseismic receiver functions and Rayleigh wave phase velocity dispersion from both ambient noise and earthquakes using data from 79 seismic stations in southern Africa, which is home to some of the world's oldest cratons and orogenic belts. The area has experienced two of the largest igneous activities in the world (the Okavango dyke swarm and Bushveld mafic intrusion) and thus is an ideal locale for investigating continental formation and evolution. The resulting 3?D shear wave velocities for the depth range of 0-100 km and crustal thickness measurements show a clear spatial correspondence with known geological features observed on the surface. Higher than normal mantle velocities found beneath the southern part of the Kaapvaal craton are consistent with the basalt removal model for the formation of cratonic lithosphere. In contrast, the Bushveld complex situated within the northern part of the craton is characterized by a thicker crust and higher crustal Vp/Vs but lower mantle velocities, which are indicative of crustal underplating of mafic materials and lithospheric refertilization by the world's largest layered mafic igneous intrusion. The thickened crust and relatively low elevation observed in the Limpopo belt, which is a late Archean collisional zone between the Kaapvaal and Zimbabwe cratons, can be explained by eclogitization of the basaltic lower crust. The study also finds evidence for the presence of a stalled segment of oceanic lithosphere beneath the southern margin of the Proterozoic Namaqua?Natal mobile belt.
DS200412-2155
2004
Gao, T.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
DS201112-1171
2011
Gao, T.Zheng, Y-F., Gao, X-Y., Chen, R-X., Gao, T.Zr in rutile thermometry of eclogite in the Dabie orogen: constraints on rutile growth during continental subduction zone metamorphism.Journal of Asian Earth Sciences, Vol. 40, 2, Jan. pp. 427-451.ChinaSubduction
DS200612-1602
2006
Gao, T.S.Zhao, Z-F., Zheng, Y-F., Gao, T.S., Wu, Y.B., Chen, B., Chen, F-K., Wu, F.Y.Isotopic constraints on age and duration of fluid assisted high pressure eclogite facies recrystallization during exhumation of deeply subducted continental crursJournal of Metamorphic Geology, Vol. 24, 8, pp. 687-702.ChinaUHP Sulu orogen
DS200412-0607
2004
Gao, W.Gao, W., Grand, S.P., Baldridge, W.S., Wilson, D., West, M., Ni, J.F., Aster, R.Upper mantle convection beneath the central Rio Grande rift imaged by P and S wave tomography.Journal of Geophysical Research, Vol. 109, 3, DOI 10.1029/2003 JB002743United States, New Mexico, Colorado PlateauGeophysics - seismics, tectonics
DS200412-2101
2004
Gao, W.West, M., Ni, J., Baldridge, W.S., Wilson, D., Aster, R., Gao, W., Grand, S.Crust and upper mantle shear wave structure of the southwest United States: implications for rifting and support for high elevatJournal of Geophysical Research, Vol. 109, 3, DOI 10.1029/2003 JB002575United States, California, Colorado PlateauGeophysics - seismics, tectonics
DS200512-1185
2005
Gao, W.Wilson, D., Aster, R., Ni, J., Grand, S., West, M., Gao, W.,Baldridge, W.S., Semken, S.Imaging the seismic structure of the crust and upper mantle beneath the Great Plains, Rio Grande Rift, and Colorado Plateau using receiver functions.Journal of Geophysical Research, Vol. 110, B5, 10.1029/2004 JB003492United States, Colorado PlateauGeophysics - seismics
DS200512-1186
2005
Gao, W.Wilson, D., Aster, R., Ni, J., Grand, S., West, M., Gao, W., Baldridge, W.S., Semken, S.Imaging the seismic structure of the crust and upper mantle beneath the Great Plains, Rio Grande Rift and Colorado Plateau using receiver functions.Journal of Geophysical Research, Vol. 110, B5 May 28, B05306 10.1029/2004 JB003492United States, ColoradoGeophysics - seismics
DS200812-1072
2008
Gao, W.Sine, C.R., Wilson, D., Gao, W., Grand, S.P., Aster, R., Ni, J., Baldridge, W.S.Mantle structure beneath the western edge of the Colorado Plateau.Geophysical Research Letters, Vol. 35, 10, May 28, L10303.United States, Colorado PlateauTectonics
DS200512-0665
2004
Gao, X.Ma, Z., Gao, X.Some thoughts on the research on continental tectonics, oceanic tectonics and earth tectonics.Earth Science Frontiers, Vol. 11, 4, pp. 9-14. Ingenta 1045384804ChinaTectonics
DS201112-0344
2011
Gao, X.Y.Gao, X.Y., Zheng, Y.F., Chen, Y.X.Dehydration melting of ultrahigh pressure eclogite in the Dabie Orogen: evidence from multiphase solid inclusions in garnet.Journal of Metamorphic Geology, in press availableChinaUHP
DS201212-0228
2012
Gao, X.Y.Gao, X.Y., Zheng, Y.F., Chen, Y.X.Dehydration melting of ultra high pressure eclogite in the Dabie Orogen: evidence from multiphase solid inclusions in garnet.Journal of Metamorphic Geology, Vol. 30, 2, pp. 193-210.ChinaUHP
DS201112-0345
2011
Gao, X-Y.Gao, X-Y., Zheng, Y-F., Chen, Y-X.U Pb ages and trace elements in metamorphic zircon and titanate from UHP eclogite in the Dabie Orogen: constraints on P-T-t path.Journal of Metamorphic Geology, in press availableChinageochronology
DS201112-0346
2011
Gao, X-Y.Gao, X-Y., Zheng, Y-F., Chen, Y-X.U-Pb ages and trace elements in metamorphic zircon and titanite from UHP eclogite in the Dabie orogen: constraints on P-T-t path.Journal of Metamorphic Geology, Vol. 29, 7, pp. 721-740.ChinaUHP
DS201112-1171
2011
Gao, X-Y.Zheng, Y-F., Gao, X-Y., Chen, R-X., Gao, T.Zr in rutile thermometry of eclogite in the Dabie orogen: constraints on rutile growth during continental subduction zone metamorphism.Journal of Asian Earth Sciences, Vol. 40, 2, Jan. pp. 427-451.ChinaSubduction
DS201312-0294
2013
Gao, X-Y.Gao, X-Y., Zheng, Y.F., Chen, Y.X., Hu, Z.Trace element composition of continentally subducted slab-derived melt: insight from multiphase solid inclusions in ultrahigh pressure eclogite in the Dabie Orogen.Journal of Metamorphic Geology, Vol. 31, 4, pp. 453-468.ChinaUHP
DS201412-0122
2014
Gao, X-Y.Chen, Y-X., Zheng, Y-F., Gao, X-Y., Hu, Z.Multiphase solid inclusions in zoisite bearing eclogite: evidence for partial melting of ultrahigh pressure metamorphic rocks during continental collision.Lithos, Vol. 200-201, pp. 1-21.ChinaSulu UHP
DS201412-0123
2014
Gao, X-Y.Chen, Y-X., Zheng, Y-F., Gao, X-Y., Hu, Z.Multiphase solid inclusions in zoisite bearing eclogite: evidence for partial melting of ultrahigh-pressure metamorphic rocks during continental collision.Lithos, Vol. 200-201, pp. 1-21.MantleEclogite
DS201412-0266
2014
Gao, X-Y.Gao, X-Y., Zheng, Y-F., Chen, Y-X., Hu, Z.Composite carbonate and silicate multiphase solid inclusions in metamorphic garnet from ultrahigh-P eclogite in the Dabie orogen.Journal of Metamorphic Geology, Vol. 32, 9, pp. 961-980.ChinaSubduction
DS201708-1644
2017
Gao, X-Y.Gao, X-Y.Multiphase solid inclusions in UHP eclogite from the Dabie orogen: constraints on anatectic melts during continental collision.11th. International Kimberlite Conference, PosterChinaUHP
DS201012-0594
2010
Gao, Y.Posukhova, T.V., Dorofeev, S.A., Gao, Y.Mineralogy of the wastes from diamond bearing mines. Arkangelsk LiaoninInternational Mineralogical Association meeting August Budapest, abstract p. 349.Russia, ChinaMining - recycling
DS201312-0180
2013
Gao, Y.Crampin, S., Gao, Y.The new geophysics.Terra Nova, Vol. 25, 3, pp. 173-180.MantleFluid-rock deformation
DS201412-0644
2013
Gao, Y.Obayashi, M., Yoshimitsu, J., Noelt, G., Fukao, Y., Shiobara, H., Sugioka, H., Miyamachi, H., Gao, Y.Finite frequency whole mantle P wave tomography: improvement of subducted slab images.Geophysical Research Letters, Vol. 40, 21, pp. 5652-5657.MantleTomography
DS201911-2523
2019
Gao, Y.Gao, Y., Yin, P.Determination of crystallite size of nanodiamond by raman spectroscopy.Diamond & Related Materials, Vol. 99, 107524Globalnanodiamond

Abstract: Although the phonon confinement model (PCM) was claimed to be successfully used to accurately calculate the size of larger Si nanocrystals, quantitative size characterization by Raman spectra still remains a challenge in the case of nanodiamonds due to its complexity. Here, we find that a local-mode model of Raman spectra developed recently can be employed to determine the bond number of the ordered diamond core in nanodiamonds, and then furtherly determine the size of nanodiamonds. The Raman lines of nanodiamonds of 3.0?nm, 2.0?nm, 2.2?nm, 3.3?nm, 3.7?nm 4.42?nm and 6.3?nm are calculated. Results are in good agreement with the measured Raman spectra. It not only provides a new approach to predict the size of nanodiamonds accurately by Raman spectra, but also helps to clarify issues in Raman spectra of nanodiamond and other carbon nanomaterials.
DS201609-1747
2016
Gao, Y-J.Su, B., Chen, Y., Guo, S., Chu, Z-Y., Liu, J-B., Gao, Y-J.Carbonatitic metasomatism in orogenic dunites from Lijiatun in the Sulu UHP terrane, eastern China.Lithos, Vol. 262, pp. 266-284.ChinaCarbonatite

Abstract: Among orogenic peridotites, dunites suffer the weakest crustal metasomatism at the slab-mantle interface and are the best lithology to trace the origins of orogenic peridotites and their initial geodynamic processes. Petrological and geochemical investigations of the Lijiatun dunites from the Sulu ultrahigh-pressure (UHP) terrane indicate a complex petrogenetic history involving melt extraction and multistage metasomatism (carbonatitic melt and slab-derived fluid). The Lijiatun dunites consist mainly of olivine (Fo = 92.0-92.6, Ca = 42-115 ppm), porphyroblastic orthopyroxene (En = 91.8-92.8), Cr-spinel (Cr# = 50.4-73.0, TiO2 < 0.2 wt.%) and serpentine. They are characterized by refractory bulk-rock compositions with high MgO (45.31-47.07 wt.%) and Mg# (91.5-91.9), and low Al2O3 (0.48-0.70 wt.%), CaO (0.25-0.44 wt.%) and TiO2 (< 0.03 wt.%) contents. Whole-rock platinum group elements (PGE) are similar to those of cratonic mantle peridotites and Re-Os isotopic data suggest that dunites formed in the early Proterozoic (~ 2.2 Ga). These data indicate that the Lijiatun dunites were the residues of ~ 30% partial melting and were derived from the subcontinental lithospheric mantle (SCLM) beneath the North China craton (NCC). Subsequent carbonatitic metasomatism is characterized by the formation of olivine-rich (Fo = 91.6-92.6, Ca = 233-311 ppm), clinopyroxene-bearing (Mg# = 95.9-96.7, Ti/Eu = 104-838) veins cutting orthopyroxene porphyroblasts. Based on the occurrence of dolomite, mass-balance calculation and thermodynamic modeling, carbonatitic metasomatism had occurred within the shallow SCLM (low-P and high-T conditions) before dunites were incorporated into the continental subduction channel. These dunites then suffered weak metasomatism by slab-derived fluids, forming pargasitic amphibole after pyroxene. This work indicates that modification of the SCLM beneath the eastern margin of the NCC had already taken place before the Triassic continental subduction. Orogenic peridotites derived from such a lithospheric mantle wedge may be heterogeneously modified prior to their incorporation into the subduction channel, which would set up a barrier for investigation of the mass transfer from the subducted crust to the mantle wedge through orogenic peridotites.
DS201610-1912
2016
Gao, Y-J.Su, B., Chen, Y., Guo, S., Chu, Z-Y., Liu, J-B., Gao, Y-J.Carbonatitic metasomatism in orogenic dunites from Lijiatun in the Sulu UHP terrane, eastern China.Lithos, Vol. 262, pp. 266-284.ChinaUHP, carbonatite

Abstract: Among orogenic peridotites, dunites suffer the weakest crustal metasomatism at the slab-mantle interface and are the best lithology to trace the origins of orogenic peridotites and their initial geodynamic processes. Petrological and geochemical investigations of the Lijiatun dunites from the Sulu ultrahigh-pressure (UHP) terrane indicate a complex petrogenetic history involving melt extraction and multistage metasomatism (carbonatitic melt and slab-derived fluid). The Lijiatun dunites consist mainly of olivine (Fo = 92.0-92.6, Ca = 42-115 ppm), porphyroblastic orthopyroxene (En = 91.8-92.8), Cr-spinel (Cr# = 50.4-73.0, TiO2 < 0.2 wt.%) and serpentine. They are characterized by refractory bulk-rock compositions with high MgO (45.31-47.07 wt.%) and Mg# (91.5-91.9), and low Al2O3 (0.48-0.70 wt.%), CaO (0.25-0.44 wt.%) and TiO2 (< 0.03 wt.%) contents. Whole-rock platinum group elements (PGE) are similar to those of cratonic mantle peridotites and Re-Os isotopic data suggest that dunites formed in the early Proterozoic (~ 2.2 Ga). These data indicate that the Lijiatun dunites were the residues of ~ 30% partial melting and were derived from the subcontinental lithospheric mantle (SCLM) beneath the North China craton (NCC). Subsequent carbonatitic metasomatism is characterized by the formation of olivine-rich (Fo = 91.6-92.6, Ca = 233-311 ppm), clinopyroxene-bearing (Mg# = 95.9-96.7, Ti/Eu = 104-838) veins cutting orthopyroxene porphyroblasts. Based on the occurrence of dolomite, mass-balance calculation and thermodynamic modeling, carbonatitic metasomatism had occurred within the shallow SCLM (low-P and high-T conditions) before dunites were incorporated into the continental subduction channel. These dunites then suffered weak metasomatism by slab-derived fluids, forming pargasitic amphibole after pyroxene. This work indicates that modification of the SCLM beneath the eastern margin of the NCC had already taken place before the Triassic continental subduction. Orogenic peridotites derived from such a lithospheric mantle wedge may be heterogeneously modified prior to their incorporation into the subduction channel, which would set up a barrier for investigation of the mas
DS1999-0220
1999
Gao Mai, et al.Flint, D.J., Gao Mai, et al.Mineral and petroleum exploration and development in Western Australia in1997-8. Brief mention of diamondsAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin., No. 1, Feb. pp. 22-25.Australia, Western AustraliaNews item, Diamonds mentioned p. 25.
DS1990-0512
1990
Gao ShanGao Shan, Zhang Benren, Li ZejiuGeochemical evidence for Proterozoic continental arc and continental margin rift magmatism along the northern margin of the Yangtze craton, South ChinaPrecam. Res, Vol. 47, pp. 205-221ChinaCraton -Yangtze, Tectonics -rift
DS1990-0940
1990
Gao ShanjiLiu Guangliang, Lian Dawei, Gao Shanji, Wang XiongwuMineralogy of Dahongshan lamproite in Hubei provinceInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 832-833ChinaLamproite, Dahongshan
DS1990-1635
1990
Gao YanZhou Xiuzhong, Huang Yunhaui, Qin Shuying, Deng Chujun, Gao Yan, YangStudies on the type and the typomorphic characteristics of the garnets From kimberlites and the relationship between the garnets and diamondInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 141-142ChinaMineralogy -garnets, Diamond morphology
DS1991-1932
1991
Gao YanZhou Xiouzhong, Huang Yunhui, Qin Shuying, Gao Yan, Yang JianminTypes, typomorphic characteristics of garnet from kimberlites in Shandong and Liaoning and its relationship with diamond.*CHIYanshi Kuangwuxue Zazhi (Acta Petrologica et Mineralogica)*CHI, Vol. 10, No. 3, August pp. 252-264ChinaPetrology, Garnets from kimberlites
DS1995-0578
1995
Gao YanGao Yan, Li Jingzhi, Zhang BeiliThe infrared microscope and rapid identification of gemstonesJournal of Gemology, Vol. 24, No. 6, April, pp. 411-414.GlobalMicroscopy
DS2001-1077
2001
Gao.S.S.Silver, P.G., Gao.S.S., Lio, K.H.Mantle deformation beneath southern Africa #2Geophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2493-6.South AfricaGeophysics - seismics, Craton - evolution Kaapvaal, Zimbabwean, Kaapvaal Craton
DS1994-0571
1994
Gaolathe, B.Gaolathe, B.Lessons from Botswana mining experienceRaw Materials Report, Vol. 9, No. 3, pp. 2-14.BotswanaMining, Development, legal, laws
DS1989-0468
1989
Gaonach, H.Gaonach, H., Picard, C., Ludden, J.N., Francis, D.M.Alkaline rocks from a Proterozoic volcanic island in the Cape Smith thrustbelt, New Quebec.Geoscience Canada, Vol. 16, No. 3, September pp. 137-139QuebecBasanite, Nephelinite, phonolites, Proterozoic
DS1992-0512
1992
Gaonach, H.Gaonach, H., Ludden, Picard, FrancisHighly alkaline lavas in a Proterozoic rift zone: implications for Precambrian mantle metasomatic processGeology, Vol. 20, Mar. pp. 247-50.Labrador, Ungava, QuebecTectonics, Cape Smith thrust belt, Mantle metasomatism, Alkaline lavas, Nephelinites, basanites
DS1989-0469
1989
Gaonac'h, H.Gaonac'h, H., Picard, C., Ludden, J.N., Francis, D.M.Alkaline rocks from a Proterozoic volcanic island In the Cape Smith thrust belt, New QuebecGeoscience Canada, Vol. 16, No. 3, pp. 137-9.Quebec, Ungava, LabradorAlkaline rocks
DS201511-1877
2015
Gaonkar, M.Sastry, M.D., Mane, S., Gaonkar, M., Bhide, M.K., Desai, S.N., Ramachandran, K.T.Luminescence studies of gemstones and diamonds.International Journal of Luminescence and Applications, Vol. 5, 3, pp. 293-297.TechnologyLuminescence

Abstract: Some of the minerals like Corundum, chryso beryl, beryllium alumino silicate (emerald) and also Diamond exhibit exceptional optical properties[1] and in some cases attractive colours; in India these were recognized quite early since the days of Indus valley civilization. In more recent times there has been a lot of scientific interest in colours and colour modifications in Gem minerals and in Diamonds. Science of gem stones deals with their identification by non destructive means and understanding of origin of colour and excellent optical properties[1]. Optical methods have long been used to obtain properties like ‘Refractive Index’ which still remains an important parameter as a preliminary test to identify the gemstone/mineral. The spectroscopic studies of gem grade minerals are essentially directed towards some of these features in identifying and understanding the spectral properties of chromophores, either chemical impurities and/or radiation induced point defects, in solids. In this context a variety of spectroscopic methods are used to address the problems of the Gem stone identification and identification of origin of colours and colour modification treatments. The methods frequently used in Gem testing labs are the following: (i)Electronic absorption in UV-Visible-NIR range.(ii)UV-Vis excited luminescence, (iii) Vibrational spectra – Absorption in the Infra red range (iv) Vibrational spectra using Light Scattering (Raman spectroscopy) (v)Surface Fluorescence mapping Under deep UV excitation. The present paper deals with the luminescence studies in rubies, sapphires, emeralds and diamonds. Special mention may be made of fluorescence mapping using deep UV excitation (around 205 nm) corresponding to the band gap of diamond. Under such an excitation inter band excitation takes place creating a e-h pair and most of the absorption and subsequent emission being restricted to the surface. This makes surface mapping possible and thereby elucidating the growth patterns. This is invaluable in the diagnostics for the detection of synthetic diamonds. In this introductory presentation on the Luminescence methods in Gemmology, we give a brief account of optical spectroscopic methods which mainly deal with identification of corundum based gem stones (rubies, sapphire) and diamonds including the electronic absorption and luminescence of chromophore centres. In gem testing infrared absorption and Raman scattering methods are main work horses and they will be brought in as and when necessary to give a complete picture.
DS1989-0470
1989
Gapais, D.Gapais, D.Shear structures within deformed granites: mechanical and thermalindicatorsGeology, Vol. 17, No. 12, December pp. 1144-1147GlobalStructure -shears, Granites
DS1995-1598
1995
Gapais, D.Roman Berdiel, T., Gapais, D., Brun, J.P.Analogue models of laccolith formationJournal of Structural Geology, Vol. 17, No. 9, pp. 1337-1346GlobalMagma -intrusions, Laccoliths
DS1995-1599
1995
Gapais, D.Roman-Berdiel, T., Gapais, D., Brun, J.P.Analogue models of laccolith formationJournal of Structural Geology, Vol. 17, No. 9, pp. 1337-1346.GlobalLaccolith, Model - not specific to kimberlites
DS1996-0351
1996
Gapais, D.De Urreiztieta, M., Gapais, D., Rossello, E.Cenozoic dextral transpression and basin development at the southern edge of the Puna PlateauTectonophysics, Vol. 254, No. 1-2, March 30, pp. 17-40ArgentinaTectonics, Puna Plateau
DS200512-0314
2005
Gapais, D.Gapais, D., Brun, J-P., Cobbold, P.R.Deformation mechanisms, rheology and tectonics: from minerals to the lithosphere.Geological Society of London, SP 243, 320p.MantleBook - review papers on rheology, UHP
DS200612-0204
2006
Gapais, D.Cagnard, F., Durrieu, N., Gapais, D., Brun, J-P, Ehlers, C.Crustal thickening and lateral flow during compression of hot lithospheres, with particular reference to Precambrian times.Terra Nova, Vol. 18, Feb. pp. 72-78.MantleGeothermometry
DS200612-0205
2006
Gapais, D.Cagnard, F., Durrieu, N., Gapais, D., Brun, J-P., Ehlers, C.Crustal thickening and lateral flow during compression of hot lithospheres, with particular reference to Precambrian times.Terra Nova, Vol. 18, 1, Feb. pp. 72-78.MantleGeophysics - seismics
DS200612-0206
2006
Gapais, D.Cagnard, F., Durrieu, N., Gapais, D., Brun, J-P., Ehlers, C.Crustal thickening and lateral flow during compression of hot lithospheres, with particular reference to Precambrian times.Terra Nova, Vol. 18, 1, pp. 72-78.MantleMelting
DS200812-0917
2007
Gapais, D.Precigout, J., Gueydan, F., Gapais, D., Garrido, C.J., Eassaifi, A.Strain localization in the subcontinental mantle ?? a ductile alternative to the brittle mantle.Tectonophysics, Vol. 445, 3-4, pp. 318-336.MantleSubduction
DS200912-0242
2009
Gapais, D.Gapais, D., Cagnard, F., Guyedan, F., Barbey, P., Bellevre, M.Mountain building and exhumation process through time: inference from nature and models.Terra Nova, Vol. 21, 3, pp. 188-194.MantleTectonics - not specific to diamonds
DS2000-0330
2000
GapeevGenshaft, Y.S., Tselmovich, GapeevPicroilmenite: factors determining its compositionDoklady Academy of Sciences, Vol. 373A, No. 6, Aug-Sept. pp.969-73.GlobalMineralogy - picroilmenite
DS1950-0388
1958
Gapeeva, G.M.Gapeeva, G.M.The Position of the Kimberlites in the Genetic Classification of Igneus Rocks.Niiga Info. Bulletin., No. 1, PP. 137-140.RussiaBlank
DS1991-0339
1991
Gapsar, J.C.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
DS200412-0608
2004
Garagash, I.A.Garagash, I.A., Ermakov, V.A.A probable geodynamic model of the Early Earth.Doklady Earth Sciences, Vol. 394, 1, pp. 73-77.GlobalTectonomagmatic, geochronology
DS200712-0348
2006
Garai, J.Garai, J., Haggerty, S.E., Rekhi, S., Chance, M.Infrared absorption investigations confirm the extraterrestrial origin of carbonado diamonds.The Astrophysical Journal, Vol. 653, Dec. 20, pp. L153-L156.TechnologyCarbonado diamonds
DS202001-0028
2019
Garakoev. A.Moilanen, J., Pavlov, B., Karshakov, E., Volovitsky, A., Garakoev. A.Airborne geophysical technologies as a basis for diamond field prognoses in regional and state scale.2019 Twelth International Conference Oct 1-3. Moscow, IEEE DOI 11.09/MLSD .2019.8911014Africa, Angola, Russia, Yakutiageophysics

Abstract: We show how to increase the effectiveness of the prognoses of kimberlite bodies by using airborne geophysical technologies. We show the advantages of electromagnetic and magnetic methods for predicting kimberlite pipes. You will see examples of a regional diamond survey in Angola and Siberia.
DS2002-0071
2002
GaraninAshchepkov, I.V., Vladykin, N.V., Mitchell, R.H., Coopersmith, H., GaraninMantle evolution beneath the Colorado Plateau: interpretation of the study of mineralDoklady Earth Sciences, Vol. 385A, 6, July-August, pp. 721-6.ColoradoTectonics, geochemistry, Deposit - Kelsey Lake
DS201112-0639
2011
GaraninMalkovets, V.G., Griffin, Pearson, Rezvukhin, O'Reilly, Pokhilenko, Garanin, Spetsius, LitasovLate metasomatic addition of garnet to the SCLM: Os-isotope evidence.Goldschmidt Conference 2011, abstract p.1395.RussiaUdachnaya, Daldyn
DS1993-1651
1993
Garanin, D.A.Varlamov, D.A., Garanin, D.A., Kostroviski, S.I.Unusual association of ore minerals in inclusion of garnet from International kimberlite pipe. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 328, No. 5, Feb. pp. 596-600.Russia, YakutiaMineral inclusions, Deposit -International
DS201708-1645
2017
Garanin, K.Garanin, K.Zarya diamond deposit, Yakutian Province, Russia.11th. International Kimberlite Conference, PosterRussia, Yakutiadeposit - Zarya
DS201903-0511
2018
Garanin, K.Garanin, K.Alrosa - world top diamond producer.7th Symposio Brasleiro de geologia do diamante, 54p ppts AvailableRussiaoverview
DS202108-1284
2021
Garanin, K.Garanin, V., Garanin, K., Kriulina, G., Samosorov, G.Geological summary of kimberlites and related rocks in the Archangelsk diamondiferous region ( ADR).Book: Diamonds from the Arkangelk Province, NW Russia., July doi.10.1007/978-3-030-35717-7_1 30p.Russia, Archangelkimberlites

Abstract: The chapter headlines the historical perspective of discovering the Arkhangelsk Diamondiferous Region, previously was also called the Arkhangelsk Diamondiferous Province (hereinafter named ADR), offers the contemporary concept of the ADR geology, and location of kimberlite fields and magmatic rock bodies in its area. It describes the layout, structure, mineralogical characteristics and lithology of pipes from the Grib and Lomonosov deposits. It gives a snapshot of the alkaline ultrabasic rocks’ representatives from the Zimny Bereg area of the ADR that is not covered by the deposits.
DS202111-1766
2021
Garanin, K.Garanin, V., Garanin, K., Kriulina, G., Samosorov, G.Diamonds from the Arkangelsk Province, NW Russia. ENGLISHSpringer Mineralogy http://www.springer.com/series/13488, Reference to the book only! Russia, Arkangelskdiamond - morphology

Abstract: Provides researchers the latest data on the Arkhangelsk and Yakutian Diamondiferous Provinces in Russia. Enriches readers’ understanding of diamond geology and its evolution. Illustrates the complete process of diamond formation in the Archangelsk Diamondiferous Provinces.
DS2003-0125
2003
Garanin, K.V.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Garanin, K.V., Kudryavtseva, G.P.Xenoliths of mantle metamorphic rocks from the Diamondiferous V. Grib pipe (8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractRussia, ArkangelskDeposit - Grib
DS200412-0173
2003
Garanin, K.V.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Garanin, K.V., Kudryavtseva, G.P.Xenoliths of mantle metamorphic rocks from the Diamondiferous V. Grib pipe ( Arkangelsk province): petrology and genetic aspects8 IKC Program, Session 6, POSTER abstractRussia, Kola Peninsula, ArchangelMantle petrology Deposit - Grib
DS200512-0026
2005
Garanin, K.V.Appollonov, V.N., Verzhak, V.V., Garanin, K.V., Garanin, V.K., Kudryavtseva, G.P., Shlykov, V.G.Saponite from the Lomonosov diamond deposit.Moscow University Geology Bulletin, Vol. 59, 2, pp. 69-84.Russia, Kola Peninsula, ArchangelGeology
DS200512-0315
2004
Garanin, K.V.Garanin, K.V.Alkaline ultrabasic rocks in the Arkangelsk diamond province: present state of knowledge and prospects for studies.Moscow University Geology Bulletin, Vol. 59, 1, pp. 35-45.Russia, Kola Peninsula, ArchangelAlkalic
DS200612-0345
2006
Garanin, K.V.Dorjnamjaa, D., Selenge, D., Garanin, K.V.Diamond bearing astropipes in Mongolia their recognition and characteristics.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1. abstract only.Asia, MongoliaUHP Breccia pipes
DS200712-1118
2006
Garanin, K.V.Verzhak, D.V., Garanin, K.V.Diamond deposits of Arkhangelsk Oblast and environmental problems associated with their development.Moscow University Geology Bulletin, Vol. 60, 6, pp. 20-30.Russia, Kola PeninsulaEnvironmental
DS201212-0177
2012
Garanin, K.V.Dyakonov, D.B., Garanin, VK., Garanin, K.V., Bushueva, E.B., Enalieva, M.A., Wedensky, E.S.Searching for new diamond deposits in western Liberia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, LiberiaProspects - Yambassen, Kumgbo
DS201212-0229
2012
Garanin, K.V.Garanin, V.K., Anashkin, S.M., Bovkun, A.V., Jelsma, H., Shmakov, I.I., Garanin, K.V.Groundmass microcrystalline oxides from the Marsfontein pipe ( RSA) , Catoca, Camachia and other Angolan kimberlite pipes.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, Angola, South AfricaDeposit - Marsfontein, Catoca, Camachia
DS201212-0733
2012
Garanin, K.V.Tretyachenko, W., Bovkun, A.V., Garanin, K.V., Garanin, V.K., Tretyachenko, N.G.Formation features of the early Hercynic alkaline ultrabasic and basic volcanic complexes from Zimny Bereg area, north east of Archangelsk region, Russia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, Archangel, Kola PeninsulaAlkalic
DS201412-0267
2014
Garanin, K.V.Garanin, V.K., Bovkun, A.V., Garanin, K.V., Kriulina, G.Y., Iwanich, W.Diamonds and its grade in different petrochemical types of kimberlites ( based on Russian diamond deposits).6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 4p. AbstractRussiaMineral chemisty
DS201412-0268
2014
Garanin, K.V.Garanin, V.K., Garanin, K.V., Iwanuch, W.Polygenesis and discreteness of diamond formation. 6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 1p. AbstractGlobalDiamond genesis
DS201412-0269
2014
Garanin, K.V.Garanin, V.K., Garanin, K.V., Iwanuch, W.Diamonds from Russia. History6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractRussiaHistory and discoveries
DS201412-0270
2014
Garanin, K.V.Garanin, V.K., Garanin, K.V., Kriulina, G.Y.Granitoids of different geochemical types of Baikal area: their diamonds from Russia.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, http://alkaline2014.comRussiaDiamonds
DS201802-0236
2017
Garanin, K.V.Garanin, K.V.Polygenesis and discrete character - fundamental basis for the natural diamond genesis. *** IN RUSStarosin, V.I. (ed) Problems of the mineralogy, economic geology and mineral resources. MAKS Press, Moscow *** IN RUS, pp. 88-127.Technologydiamond morphology
DS201802-0237
2017
Garanin, K.V.Garanin, K.V., Serov, I.V., Nikiforova, A.Yu., Grakhanov, O.S.The ALROSA geological prospecting complex and the analysis of the base for the diamond mining in Russian Federation to 2030. *** IN RUSStarosin, V.I. (ed) Problems of the mineralogy, economic geology and mineral resources. MAKS Press, Moscow *** IN RUS, pp. 22-40.Russiatechnology
DS201808-1722
2018
Garanin, K.V.Agashev, A.M., Nakai, S., Serov, I.V., Tolstov, A.V., Garanin, K.V., Kovalchuk, O.E.Geochemistry and origin of the Mirny field kimberlites, Siberia.Mineralogy and Petrology, doi.org/10.1007/s00710-018-06174 12p.Russia, Siberiadeposit - Mirny

Abstract: Here we present new data from a systematic Sr, Nd, O, C isotope and geochemical study of kimberlites of Devonian age Mirny field that are located in the southernmost part of the Siberian diamondiferous province. Major and trace element compositions of the Mirny field kimberlites show a significant compositional variability both between pipes and within one diatreme. They are enriched in incompatible trace elements with La/Yb ratios in the range of (65-00). Initial Nd isotope ratios calculated back to the time of the Mirny field kimberlite emplacement (t?=?360 ma) are depleted relative to the chondritic uniform reservoir (CHUR) model being 4 up to 6 ?Nd(t) units, suggesting an asthenospheric source for incompatible elements in kimberlites. Initial Sr isotope ratios are significantly variable, being in the range 0.70387-0.70845, indicating a complex source history and a strong influence of post-magmatic alteration. Four samples have almost identical initial Nd and Sr isotope compositions that are similar to the prevalent mantle (PREMA) reservoir. We propose that the source of the proto-kimberlite melt of the Mirny field kimberlites is the same as that for the majority of ocean island basalts (OIB). The source of the Mirny field kimberlites must possess three main features: It should be enriched with incompatible elements, be depleted in the major elements (Si, Al, Fe and Ti) and heavy rare earth elements (REE) and it should retain the asthenospheric Nd isotope composition. A two-stage model of kimberlite melt formation can fulfil those requirements. The intrusion of small bodies of this proto-kimberlite melt into lithospheric mantle forms a veined heterogeneously enriched source through fractional crystallization and metasomatism of adjacent peridotites. Re-melting of this source shortly after it was metasomatically enriched produced the kimberlite melt. The chemistry, mineralogy and diamond grade of each particular kimberlite are strongly dependent on the character of the heterogeneous source part from which they melted and ascended.
DS201312-0018
2013
Garanin, V.Anashkin, S., Bovkun, A.,Bindi, L., Garanin, V.,Litvin, Y.Kudryavtsevaite - a new kimberlitic mineral.Mineralogical Magazine, Vol. 77, 3, pp. 327-334.TechnologyMineral chemistry
DS201708-1646
2017
Garanin, V.Garanin, V.The relationship among various morphological types of diamonds within diamond deposits in Russia: genesis, growth, dissolution and real diamond grade.11th. International Kimberlite Conference, PosterRussiadiamond morphology
DS202108-1284
2021
Garanin, V.Garanin, V., Garanin, K., Kriulina, G., Samosorov, G.Geological summary of kimberlites and related rocks in the Archangelsk diamondiferous region ( ADR).Book: Diamonds from the Arkangelk Province, NW Russia., July doi.10.1007/978-3-030-35717-7_1 30p.Russia, Archangelkimberlites

Abstract: The chapter headlines the historical perspective of discovering the Arkhangelsk Diamondiferous Region, previously was also called the Arkhangelsk Diamondiferous Province (hereinafter named ADR), offers the contemporary concept of the ADR geology, and location of kimberlite fields and magmatic rock bodies in its area. It describes the layout, structure, mineralogical characteristics and lithology of pipes from the Grib and Lomonosov deposits. It gives a snapshot of the alkaline ultrabasic rocks’ representatives from the Zimny Bereg area of the ADR that is not covered by the deposits.
DS202111-1766
2021
Garanin, V.Garanin, V., Garanin, K., Kriulina, G., Samosorov, G.Diamonds from the Arkangelsk Province, NW Russia. ENGLISHSpringer Mineralogy http://www.springer.com/series/13488, Reference to the book only! Russia, Arkangelskdiamond - morphology

Abstract: Provides researchers the latest data on the Arkhangelsk and Yakutian Diamondiferous Provinces in Russia. Enriches readers’ understanding of diamond geology and its evolution. Illustrates the complete process of diamond formation in the Archangelsk Diamondiferous Provinces.
DS1983-0594
1983
Garanin, V.G.Tatarintsev, V.I., Tsymbal, S.N., Garanin, V.G., Kudryatseva, G.Quenched Particles from Kimberlites of YakutiaDoklady Academy of Science USSR, Earth Science Section., Vol. 270, No. 1-6, PP. 144-148.RussiaPetrography
DS200512-0033
2002
Garanin, V.G.Ashchepkov, I.V., Vladykin, N.V., Mitchell, R.H., Coopersmith, H., Garanin, V.G.Geochemical features of the minerals from the heavy concentrate from KL-1 Kelsey lake kimberlite, State Line, Colorado: petrologic reconstruction.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 163-173.United States, ColoradoGeochemistry - Kelsey Lake
DS1960-0638
1966
Garanin, V.K.Botkunov, A.I., Garanin, V.K., Kudryavtseva, G.P., Kharlamov, Ye.S.First find of syngenetic dolomite inclusions in zircon from the Mirkimberlite pipeDoklady Academy of Science USSR, Earth Science Section, Vol. 278, No. 1-6, pp. 161-164RussiaPetrology, Zircon
DS1975-0694
1978
Garanin, V.K.Bocharova, G.I., Garanin, V.K., Jilyaeva, V.A., Kudryavtseva, G.New Dat a on Exolution Lamellae in Picroilmenites from Jakutia Kimberlite Pipes.Jeol. News, Vol. 16E, No. 1, PP. 18-24.Russia, YakutiaMineralogy, Genesis, Kimberlite
DS1975-1026
1979
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Malkov, B.A.Mantle Inclusions in Diatremes of the Northeastern Party Of the Russian PlatformDoklady Academy of Science USSR, Earth Science Section., Vol. 249, No. 1-6, PP. 140-143.RussiaPetrography
DS1975-1027
1979
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Soshkina, L.T.Possible Applications of Thermomagnetic Analysis in Kimberlite Body Prospecting.Vses. Mineral O-vo Zap., No. 5, PP. 621-630.RussiaKimberlite, Geophysics
DS1981-0095
1981
Garanin, V.K.Botkunov, A.I., Garanin, V.K., et al.Sulfide Inclusions in Olivine from the Udachnaya Kimberlitepipe.Doklady Academy of Science USSR, Earth Science Section., Vol. 247, No. 1-6, PP. 113-117.RussiaPetrography
DS1981-0167
1981
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P.(the Nature of Heterogeneity in Ilmenite from Kimberlites.)Mineral. Zhur., Vol. 3, No. 1, PP. 75-83.RussiaKimberlite
DS1982-0215
1982
Garanin, V.K.Garanin, V.K., Kudriavtseva, G.P., et al.A New Variety of Eclogites in Yakutian KimberlitesDoklady Academy of Sciences Nauk SSSR., Vol. 262 , No. 6, PP. 1450-1455.RussiaKimberlite
DS1982-0216
1982
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Kharkiv, A.D., Chistyakova, V.K.New Varieties of Eclogite of Yakutia KimberlitesDoklady Academy of Sciences Nauk SSSR., Vol. 262, No. 6, PP. 1450-1455.RussiaMineralogy
DS1983-0239
1983
Garanin, V.K.Garanin, V.K., Krot, A.N., Kudryavtseva, G.P.Evolution of Peridotitic and Eclogitic Magmas in Kimberlitepipes.Geol. Rudn. Mest., Vol. 25, No. 4, PP. 14-28.RussiaKimberlite, Petrology, Geochemistry
DS1983-0240
1983
Garanin, V.K.Garanin, V.K., Kudriavtseva, G.P., Soshkina, L.T.Genesis of Ilmenite from KimberlitesDoklady Academy of Science USSR, Earth Science Section., Vol. 172, No. 1-6, MARCH PP. 102-106.RussiaGenesis, Petrography, Mineralogy
DS1983-0241
1983
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., et al.Mineralogy of the Ilmenite Bearing Hyperbasites of Mir Kimberlite Pipe.Academy of Science SSSR GEOL. SER. Bulletin., No. 2, PP. 84-95.RussiaMineralogy
DS1983-0242
1983
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., et al.Mineralogy of the Ilmenite Bearing Hyperbasites of the Mirkimberlite Pipe.Izv. Akad. Nauk Sssr, Geol. Ser., No. 2, FEBRUARY, PP. 84-95.Russia, YakutiaMineralogy
DS1983-0243
1983
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Kharkiv, A.D.First discovery of a deep rock of complex composition in the Udachnaya kimberlite pipe.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 269, No. 6, pp. 1449-1454RussiaBlank
DS1983-0244
1983
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Kharkiv, A.D., Chistyakova, V.K.New Eclogite Variety in Kimberlite Pipes of YakutiaDoklady Academy of Science USSR, Earth Science Section., Vol. 262, No. 1-6, PP. 147-151.Russia, YakutiaMir, Xenoliths, Inclusions, Chemical Analyses, Geochemistry
DS1983-0432
1983
Garanin, V.K.Marakushev, A.A., Garanin, V.K., Kudryavtseva, G.P.The Mineralogy and Petrology of Kimberlite Pipes and Diamond Bearing Rocks.Annales Scientifiques De L' Universite De Clermont-ferrand Ii, No. 74, PP. 47-54.RussiaPetrography, Genesis, Magma
DS1984-0002
1984
Garanin, V.K.Afanasev, V.P., Varlamov, V.A., Garanin, V.K.The Abrasion of Minerals in Kimberlites in Relation to the Conditions and Distances of Their Transportation.Soviet Geology And Geophysics, Vol. 25, No. 10, OCTOBER PP. 112-117.RussiaMorphology, Petrography
DS1984-0165
1984
Garanin, V.K.Botkunov, A.I., Garanin, V.K., et al.Ist Occurrence of Syngenetic Inclusions of Dolomite in Zirconium from the Kimberlite Pipe, Mir.Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 278, No. 5, PP. 1214-1217.RussiaGenesis
DS1984-0290
1984
Garanin, V.K.Garanin, V.K.Ilmenite from Kimberlites.(russian)Moscow: Izd. Mosk.(Russian), 240p. Geological Society of Canada (GSC).RussiaMineralogy, Kimberlite
DS1984-0291
1984
Garanin, V.K.Garanin, V.K., Krot, A.N., Kudryavtseva, G.P.The Evolution of Peridotite and Eclogite Magmas in Kimberlite Pipes.International Geology Review, Vol. 26, No. 1, PP. 82-97.RussiaGenesis
DS1985-0075
1985
Garanin, V.K.Botkunov, A.I., Garanin, V.K., Krot, A.N., et al.Primary Hydrocarbon Inclusions in Garnets from the Mir and Sputnik Kimberlite Pipes.Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 280, No. 2, PP. 468-472.RussiaBlank
DS1985-0214
1985
Garanin, V.K.Garanin, V.K., Kudryavceva, G.P., Kharkiv, A.D.The Pecularities of Eclogites from Kimberlite Pipes in Yakutia.Terra Cognita., Vol. 5, No. 4, AUTUMN, P. 441-2, (abstract.).RussiaMineralogy
DS1985-0215
1985
Garanin, V.K.Garanin, V.K., Kudryavt, G.P., Kharkiv, A.D.Mineralogy of Ilmenitic Hyperbasaites from Obnazhennaya Kimberlite Pipe.Inzvest. Akad. Nauk, Geol. Ser., No. 5, MAY PP. 85-101.RussiaMineralogy
DS1985-0216
1985
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Kharkiv, A.D., Chistyakova, V.K.Mineralogy of ultrabasites with ilmenite of the Obnazhennaya kimberlitepipe.(Russian)Izves. Akad. Nauk SSSR, Ser. Geol.(Russian), No. 5, pp. 85-101RussiaPetrology, Mineralogy
DS1985-0217
1985
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Kharkiv, A.D., Chistyakova, V.K.Mineralogy of Ilmenitic Ultrabasic Rocks from the Obnazhennaya Kimberlite Pipe.Izv. Akad. Nauk Sssr Ser. Geol., No. 5, PP. 85-101.Russia, SiberiaMineralogy, Lherzolite
DS1986-0080
1986
Garanin, V.K.Bocharova, G.I., Garanin, V.K., Kudryavtseva, G.P.Sulfide mineralization in the kimberlite of YakutiaInternational Mineralogical Association Meeting, held Bulgaria Sept. 1982, Publishing in:, Vol. 13, pp. 107-119RussiaSulphides, Kimberlite
DS1986-0093
1986
Garanin, V.K.Botkunov, A.I., Garanin, V.K., Ivanova, T.N., Krot, A.N., KudryavtsevaOptical and colorimetric spectroscopic characteristics of garnets withNov. Dann. O Minetal. Moskva, (Russian), No. 33, pp. 120-129RussiaMineralogy, Garnet
DS1986-0094
1986
Garanin, V.K.Botkunov, A.I., Garanin, V.K., Krot, A.N., Kudryavtseva, G.P., MatsyukPrimary hydrocarbon inclusions in garnets from the Mir and Sputnikkimberlite pipesDoklady Academy of Science USSR, Earth Science Section, Vol. 280, No. 1-6, October pp. 136-141RussiaMineralogy, Garnet
DS1986-0095
1986
Garanin, V.K.Botkunov, A.I., Garanin, V.K., Kudryavtseva, G.P., Kharlamov, Ye.S.First find of syngenetic dolomitic inclusions in zircon from the Mirkimberlite pipeDoklady Academy of Science USSR, Earth Science Section, Vol. 278, No. 1-6, April, pp. 161-164RussiaMineralogy
DS1986-0261
1986
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Krot, A.N.Role of sulfides in the evolution of mantle rocks of basic and ultrabasiccomposition and in the emergence of kimberlitebodiesProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 178-180RussiaBlank
DS1986-0262
1986
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Matsyuk, S.S., Cherenkova, A.F.Deep seated mineral associations of kimberlites from the SouthWestern periphery of the Anabar massif.(Russian)Mineral Zhurn., (Russian), Vol. 8, No. 4, pp. 20-32RussiaPetrology, Mineralogy
DS1986-0263
1986
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Posukhova, T.V., Afanasjev, V.P.Morphology of kimberlite minerals: its usage for predicting and searchingfor diamond depositsProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 457-459RussiaDiamond exploration
DS1986-0264
1986
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Prewitt, C.T.Mineralogy of ilmenite from Yakutia kimberlites14th. International Meeting I.m.a., P. 109. (abstract.)RussiaKimberlite mineralogy, Ilmenite
DS1986-0265
1986
Garanin, V.K.Garanin, V.K., Zhilyaeva, V.A., Kudyavtskaya, G.P., Savrasov, D.I.Fanciful cuts created by laser sawingGems and Gemology, Vol. XXII Fall, p. 170GlobalDiamond cutting
DS1986-0266
1986
Garanin, V.K.Garanin, V.K., Zhilyaeva, V.A., Kudyavtskaya, G.P., Savrasov, D.I.Mineralogical factors of magnetism of kimberlite rocks.(Russian)Izvest. Annual Nauka Geol., (Russian), No. 11, November pp. 82-100RussiaGeophysics
DS1987-0068
1987
Garanin, V.K.Botkunov, A.I., Garanin, V.K., Krot, A.N., Kudryavtseva, G.P.Garnet mineral inclusions in kimberlites of Yakutia,their genetic and practical importance.(Russian)Geol. Rudyn. Mestoroz., (Russian), Vol. 29, No. 1, pp. 15-29Russia, Anabar shieldMineral inclusions, Petrology
DS1987-0069
1987
Garanin, V.K.Botkunov, A.I., Garanin, V.K., Krot, A.N., Kuryavtseva, G.P.Mineral inclusions in garnets from Yakutian kimberlites and their genetic and practical significance.*rusGeol. Rudn. Mestorozhd. *rus, Vol. 20, No. 1, pp. 15-29RussiaMineralogy
DS1987-0235
1987
Garanin, V.K.Garanin, V.K., Kudrryavtseva, G.P., Marakushev, A.A., CherenkovaA new variety of deep seated high alumin a rock in kimberlite pipesInternational Geology Review, Vol. 29, No. 11, November pp. 1366-1376RussiaFerroalkremite, analyses, Anabar region
DS1987-0236
1987
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Mikhailichencko, O.A.Vertical zoning in the Mir kimberlite pipes.(Russian)Geol. Rudn. Mestorozhd., (Russian), Vol. 29, No. 5, pp. 11-26RussiaBlank
DS1987-0237
1987
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Mikhailichenko, O.A.Rapid thermomagnetic analysis of kimberlites and estimation oftheirproductivity.(Russian)Vestn. Mosk. University of Ser. 4, Geol., (Russian), No. 2, pp. 41-49RussiaGeothermometry
DS1987-0238
1987
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Mikhailichenko, O.A.Rapid thermomagnetic analysis of the study of kimberlites and evaluation of their productivityMoscow University of Geol. Bulletin, Vol. 42, No. 2, pp. 40-47RussiaBlank
DS1987-0239
1987
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Mikhaylichenko, A.Vertical zoning of the kimberlite Mir pipe.(Russian)Geol. Rudny. Mestord., (Russian), Vol. 29, No. 5, pp. 11-26RussiaPetrology, Geothermometry
DS1987-0348
1987
Garanin, V.K.Khomemko, V.M., Matsyuk, S.S., Garanin, V.K., Kharkiv, A.D.Crystallochemical and genetic aspects of the study of clinopyroxenes from mantle peridotite nodules in kimberlites.(Russian)Doklady Academy of Science USSR, Earth Science Section, Vol. 296, No. 5, Sept-Oct., pp. 132-135RussiaGeochemistry, Kimberlite - inclusions
DS1987-0349
1987
Garanin, V.K.Khomenko, V.M., Matsiuk, S.S., Garanin, V.K., Kharkiv, A.D.Crystallochemical and genetic aspects of the study of clinopyroxenes from plutonic ultramafic inclusions in kimberlite #1Doklady Academy of Sciences Akademy Nauk SSSR (Russian), Vol. 296, No. 2, pp. 420-424RussiaGeochemistry, ultramafic inclusions
DS1987-0445
1987
Garanin, V.K.Matsuyk, S.S., Khomenko, V.M., Slodkevich, V.V., Garanin, V.K.The genesis of diamond bearing rocks of kimberlite basic structures and theMineral. Sbornik (L'Vov), (Russian), Vol. 41, No. 1, pp. 18-24RussiaAfrica, Beni Bouchera, Diamond
DS1988-0236
1988
Garanin, V.K.Garanin, V.K., Guseva, E.V., Dergach, D.V.Diamond crystals in garnets from granite gneisses.(Russian)Doklady Academy of Sciences Nauk USSR, (Russian), Vol. 298, No. 1, pp. 190-194GlobalBlank
DS1989-0460
1989
Garanin, V.K.Galimov, E.M., Botkunov, A.I., Garanin, V.K.Carbon bearing fluid inclusions in olivine and garnet from the Udachnaya kimberlite pipe.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 7, pp. 1011-1015RussiaDiamond inclusions, Garnet analyses
DS1989-0461
1989
Garanin, V.K.Galimov, E.M., Botkunov, A.I., Garanin, V.K., Spasennykh, M. Yu.Carbon-containing fluid inclusions in garnet and olivine from Kimberlites of the Udachnaya pipe. (USSR)(Russian)Geochemistry International (Geokhimiya), (Russian), No. 7, pp. 1011-1015RussiaFluid inclusions, Garnet
DS1989-0471
1989
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Mikhaylichenko, O.A., SaparinDiscreteness of the natural diamond formation process. (Russian)Mineral. Zhurnal., (Russian), Vol. 11, No. 31, pp. 3-19RussiaDiamond morphology, Natural diamond
DS1989-0772
1989
Garanin, V.K.Khomenko, V.M., Matsyuk, S.S., Garanin, V.K., Kharkiv, A.D.Crystallochemical and genetic aspects of the study of clinopyroxenes from plutonic ultramafic inclusions In kimberlite #2Doklady Academy of Science USSR, Earth Science Section, Vol. 296, No. 1-6, pp. 132-135RussiaCrystallography, Ultramafic inclusions
DS1989-1552
1989
Garanin, V.K.Verzhak, V.V., Garanin, V.K., Kudryavtseva, G.P., MikhailenkoTo the problem of diamond potential relationship to the mineral composition of kimberlites and lamproites.(Russian)Geol. Rudn. Mestorozhd., (Russian), Vol. 31, No. 2, pp. 15-27RussiaKimberlite, Lamproite
DS1989-1553
1989
Garanin, V.K.Verzhak, V.V., Garanin, V.K., Kudryavtseva, G.P., MikhailichenkoTo the problem of diamond potential relationship to the mineral composition of kimberlites andlamproites.(in Russian)Geol. Rudn. Mestorozh., (Russian), Vol. 31, No. 2, Mar-Apr. pp. 15-27RussiaLamproites, Diamond potential
DS1989-1554
1989
Garanin, V.K.Verzhak, V.V., Garanin, V.K., Kudryavtseva, G.P., MikhaylichenkoMineralogic composition of kimberlites and lamproites as an indicator of diamond potentialInternational Geology Review, Vol. 31, No. 5, pp. 484-495RussiaLamproites, Kimberlites, Mineralogy -diamond poten
DS1990-0258
1990
Garanin, V.K.Busheva, E.B., Vasiljeva, E.R., Garanin, V.K., KudrjavtsevaMineralogy of kimberlites of the northern European part of the USSRInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 786-788RussiaKimberlites, Mineralogy
DS1990-0505
1990
Garanin, V.K.Galimov, E.M., Botkunov, A.I., Garanin, V.K.Carbon bearing fluid inclusions in olivine and garnet from Udachnaya pipekimberlitesGeochemistry International, Vol. 27, No. 2, February pp. 87-90RussiaGeochronology, Carbon inclusions
DS1990-0513
1990
Garanin, V.K.Garanin, V.K.The problem of discreteness in the natural diamond formationprocess.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 5, October pp. 28-36RussiaDiamond morphology, Natural diamond
DS1990-0514
1990
Garanin, V.K.Garanin, V.K.Some new dat a on conditions of zircon formation from kimberlitesMoscow University of Geol. Bulletin, Vol. 45, No. 6, pp. 43-54RussiaKimberlites, Petrography-eclogites, zircon
DS1990-0515
1990
Garanin, V.K.Garanin, V.K., Kasimova, R., Kudryavtseva, G.P., MikhajlichenkoMineralogy of spinels from kimberlites and lamproitesInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 31-32RussiaMineralogy -spinels, Lamproites, kimberlites
DS1990-0516
1990
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P.Morphology, physical properties and paragenesis of inclusion -bearing diamonds from Yakutian kimberlitesLithos, Vol. 25, No. 1-3, November pp. 211-218RussiaDiamond inclusions, Diamond morphology
DS1990-0517
1990
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P.The discretion of the natural diamond formation processInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 675-676RussiaDiamond morphology, Diamond genesis
DS1990-0518
1990
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Matsyuk, S.S., Cherenkova, A.F., CherenkovDiscovery of zircon bearing ilmenite-amphibole-pyroxenite in kimberlitesInternational Geology Review, Vol. 32, No. 11, November pp. 1086-1094RussiaPyroxenite- zircon, Geochemistry
DS1990-0519
1990
Garanin, V.K.Garanin, V.K., Titkov, S.V.About etching patterns on diamond crystals from north European part of the USSR (technical note). (Russian)Izv. Akad. Nauk SSS*(in Russian), No. 9, September pp. 110-115RussiaDiamond morphology, Etching patterns
DS1990-0520
1990
Garanin, V.K.Garanin, V.K., Zhiljaeva, V.A., Kudrjavtseva, G.P., MikhailichenkoMineralogy of ferrimagnetic oxides and magnetic properties of Kimberlites and lamproitesInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 29-30RussiaMineralogy -oxides, Lamproites, kimberlites
DS1990-0521
1990
Garanin, V.K.Garanin, V.K., Zhukov, G.D., Kudrjavtseva, G.P., Laverova, T.N.Mineralogy of garnets with inclusions from Sitikanskaja kimberlite pipeInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 799-801RussiaMineralogy -garnets, Sitikanskaja
DS1990-1505
1990
Garanin, V.K.Varlamov, D.A., Garanin, V.K., Kudrjavtseva, G.P.Mineral inclusions in high grade metamorphism garnetsInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 896-897RussiaMicroscopy, Diamond inclusions
DS1991-0114
1991
Garanin, V.K.Bezborodov, S.M., Garanin, V.K., Kudrjavtseva, G.P., Schepina, N.A.The pecularities of the mineral composition of the diamond bearing eclogites from the Udachnaya kimberlite pipeProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 481-483RussiaDiamond morphology, Garnet composition
DS1991-0115
1991
Garanin, V.K.Bezborodov, S.M., Garanin, V.K., Kudryavtseva, G.P., et al.Mineralogy of the diamond bearing eclogites from the Udachnaya kimberlitepipe.(Russian)Mineral. Zhurn., (Russian), Vol. 13, No. 3, pp. 24-35Russia, YakutiaMineralogy, Deposit -Udachnaya
DS1991-0116
1991
Garanin, V.K.Bezborodov, S.M., Garanin, V.K., Kudryavtseva, G.P., Ponailo, I.Discovery of eclogite with generations of diamond in the Udachnaya kimberlite pipe. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 317, No. 3, pp. 714-717RussiaDiamond genesis, Eclogite
DS1991-0137
1991
Garanin, V.K.Bogatikov, O.A., Garanin, V.K., Kononova, K.A., Kudrjavtseva, G.P.Ore minerals from the lamproite ground massProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 484-485Russia, Australia, SpainOxide mineral chemistry, Diamond evaluation
DS1991-0191
1991
Garanin, V.K.Bulanova, B., Varlamov, D.A., Garanin, V.K., Kudjavtseva, G.P.Chemico-genetic classification of the most important minerals-satellites Of the diamondProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 490-491RussiaMineral chemistry, Genesis
DS1991-0532
1991
Garanin, V.K.Garanin, V.K., Kudrjavtseva, G.P.New technology of the searching of the diamond bearing kimberlites methodological basis and fields of applicationsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 505-507RussiaDiamond evaluation, Diamond genesis
DS1991-0533
1991
Garanin, V.K.Garanin, V.K., Kudrjavtseva, G.P., Laverova, T.N.The comparative characteristics of ilmenite from the kimberlite Provinces of the USSRProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 508-509RussiaIlmenite, Mineral chemistry
DS1991-0534
1991
Garanin, V.K.Garanin, V.K., Kudrjavtseva, G.P., Michailichchenko, O.A.Mineralogy of oxides from the ground mass of kimberlites of Yakutia and northern European part of the USSRProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 510-512RussiaMineralogy, Oxides
DS1991-0923
1991
Garanin, V.K.Kostrovitsky, S.I., Garanin, V.K.Chrome titanate inclusions of unusual composition in pyropes from lamprophyres and kimberlitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 525-526RussiaGarnet inclusions, Mineral chemistry
DS1991-1751
1991
Garanin, V.K.Trukhin, V.I., Verichev, E.M., Garanin, V.K., Zhilyayeva, V.A.Magnetomineralogy of kimberlite type rocks at the South European part Of the USSR.(Russian)Izvest. Akad. Nauk SSSR, (Russian), No. 7, July pp. 39-51RussiaKimberlite, Mineralogy, geophysics, magnetics
DS1992-0514
1992
Garanin, V.K.Garanin, V.K.Mineralogical zonality of kimberlitesProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 2, abstract p. 579RussiaKimberlites, Mineralogy
DS1993-0116
1993
Garanin, V.K.Bezborodov, S.M., Garanin, V.K., Kudryavtseva, G.P., Ponahlo, J.Find of eclogite with two diamond generations in the Udachnaya kimberlitepipeDoklady Academy of Sciences USSR, Earth Science Section, Vol. 317 A February Publishing date pp. 190-194Russia, YakutiaDiamond morphology, Deposit -Udachnaya
DS1993-0481
1993
Garanin, V.K.Garanin, V.K., et al.Oxide minerals and magnetic properties of lamproites from AustraliaMoscow University of Geol. Bulletin, Vol. 48, No. 3, pp. 46-58.AustraliaLamproites
DS1993-0482
1993
Garanin, V.K.Garanin, V.K., et al.Oxide minerals and magnetic properties of lamproites from Spain andRussia.Moscow University of Geol. Bulletin, Vol. 48, No. 3, pp. 37-47.GlobalLamproites
DS1993-0483
1993
Garanin, V.K.Garanin, V.K., Kasimova, F.I., Melnikov, F.P.New minerals-inclusions in zircons from the kimberlite pipe- Mir. (Russian)Doklady Academy of Sciences Akad. Nauk, (Russian), Vol. 330, No. 1, May pp. 75-78Russia, YakutiaMineral inclusions, Deposit -Mir
DS1993-0484
1993
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Janse, A.J.A.Vertical and horizontal zoning of kimberlitesPreprint, 14p.Russia, Yakutia, Arkangelsk, South AfricaZonation, Kimberlites
DS1994-0572
1994
Garanin, V.K.Garanin, V.K., et al.The diamond mineral indicators paragenesis with hydrocarbonates from the Yakutian kimberlites.9th. IAGOD held Beijing, Aug.12-18., p. 701-703. abstractRussia, YakutiaDiamond genesis, Deposit -Mir
DS1994-0573
1994
Garanin, V.K.Garanin, V.K., et al.Temperature of formation of zircon and its paragenetic association with the Mir kimberlite pipe.(Russian)Izvest. Vysshikh-Uchebnykh Zavedeniy Geol. i Raz., (Russian), No. 1, pp. 67-70.Russia, YakutiaZircon mineralogy, Deposit -Mir
DS1994-0958
1994
Garanin, V.K.Kudrjavtseva, G.P., Garanin, V.K.New dat a on the internal structure of diamond and its genesisInstitute of Mining and Metallurgy (IMM) Bulletin, Economic Geology in Europe and Beyond- abstracts of meeting, p. B196, abstract only.GlobalDiamond morphology
DS1995-0581
1995
Garanin, V.K.Garanin, V.K., Kasimova, F.I., Melnikov, F.P.New inclusion minerals from zircons in the Mir kimberlite pipeDoklady Academy of Sciences Acad. Science Russia, Vol. 331, No. 5, May pp. 54-59.RussiaMineralogy -zircons, Deposit -Mir
DS1995-0582
1995
Garanin, V.K.Garanin, V.K., Posukhova, T.V.Morphology and growth history of diamonds in Arkhangelsk kimberlite pipeProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 175-6.Russia, ArkangelskDiamond morphology, Deposit - Zolotitskoye, Verhotinskoye, Kepinskoye
DS1995-0583
1995
Garanin, V.K.Garanin, V.K., Posukhova, T.V.Typomorphism of microcrystalline oxides from kimberlite groundmass in Arkhangel kimberlite province.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 177-8.Russia, ArkangelskDiamond morphology, Deposit - Zolotitskoye, Verhotinskoye, Kepinskoye
DS1996-0144
1996
Garanin, V.K.Bobrov, A.V., Garanin, V.K.Mineralogy and genesis of pyrope peridotite zonal modulesMoscow University of Geol. Bulletin., Vol. 51, No. 1, pp. 27-36.RussiaPeridotite
DS1996-0479
1996
Garanin, V.K.Garanin, V.K., Kasimva, F.I., Melnikov, F.P.Hydrocarbon inclusions in zircon from the Mir kimberlite pipeDoklady Academy of Sciences, Vol. 336, pp. 187-189.Russia, YakutiaInclusions -zircon, Deposit -Mir
DS1996-0778
1996
Garanin, V.K.Kostrovitsky, S.I., Garanin, V.K.The composition of picroilmenite as an indicator of zonation of the kimberlite pipes clusters.International Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 393.RussiaMineralogical mapping, Clusters
DS1996-1468
1996
Garanin, V.K.Varlamov, D.A., Garanin, V.K., Kostrovitsky, S.I.Exotic high titanium minerals as inclusions in garnets from lower crustaland mantle xenoliths.Doklady Academy of Sciences, Vol. 345A, No. 9, Oct. pp. 352-355.Russia, YakutiaXenoliths, Deposit - International, Sytykan
DS1996-1472
1996
Garanin, V.K.Vasilyeva, E.R., Garanin, V.K., Kadryavtseva, G.P.Mineralogy of garnets from kimberlites of Arkangelsk diamond bearingprovince.International Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 386.RussiaGarnet mineralogy, Kimberlites
DS1997-0368
1997
Garanin, V.K.Garanin, V.K., Dummett, Amtauer, Kudryavtseva, FipkeInternal structure and spectroscopic characteristics of diamonds from Lomonosov deposit.Doklady Academy of Sciences, Vol. 353, No. 2, Feb-Mar, pp. 233-5.Russia, Kola PeninsulaDiamond - morphology, Deposit - Lomonosov
DS1997-0369
1997
Garanin, V.K.Garanin, V.K., Kudryavtseva, G.P., Posukhova, T.V.Indicators of diamond preservation in kimberlitePapunen: 4th. Biennial SGA Meeting, pp. 767-770.Russia, ArkangelskDiamond exploration, Thermodynamics, microcrystalline oxides
DS1998-0148
1998
Garanin, V.K.Bovkun, A.V., Garanin, V.K., Kudriavtseva, PossuklovaChemical genetic classification of microcrystalline oxides from kimberlite groundmass - system prospecting7th International Kimberlite Conference Abstract, pp. 91-93.Russia, Arkangelsk, Kola PeninsulaMicroprobe analyses, Deposit - Zolitskoye, Verkhotinskoye, Kepinskoye, Touri
DS1998-0149
1998
Garanin, V.K.Bovkun, A.V., Garanin, V.K., Kudriavtseva, PossuklovaDiamonds from Timan placers: morphology, spectroscopy and genesis7th International Kimberlite Conference Abstract, pp. 97-99.Russia, TimanPLacers, alluvials, Diamond morphology - types
DS1998-0150
1998
Garanin, V.K.Bovkun, A.V., Garanin, V.K., Kudriavtseva, PossuklovaChemical genetic classification of oxides from kimberlite groundmass as basis - evaluation of diamond7th International Kimberlite Conference Abstract, pp. 94-96.Russia, Yakutia, AikalHigh magnesian - spinels, Deposit - Obnazhenna, Mir, Udachnaya, Morkokka
DS1998-0466
1998
Garanin, V.K.Garanin, V.K., et al.Geological structure, mineralogical and petrological characteristics of theM.V. Lomonosov diamond deposit.Preprint submitted to Min. Deposita, approx. 35p. 17 textRussia, Arkangelsk, Kola PeninsulaMineralogy, petrology, Deposit - Lomonosov
DS1998-0467
1998
Garanin, V.K.Garanin, V.K., Kudriavtseva, G.P.Diamonds from the M.V. Lomonosov deposit, Arkangelsk diamondiferousprovince.Ima 17th. Abstract Vol., p. A15. poster abstractRussia, Arkangelsk, Kola PeninsulaDiamond morphology, Deposit - Lomonosov
DS1998-0468
1998
Garanin, V.K.Garanin, V.K., Kudriavtseva, G.P., Possukhova, T.V.Diamonds of Arkhangelsk kimberlite province ( review)7th International Kimberlite Conference Abstract, pp. 233-235.Russia, Arkangelsk, Kola PeninsulaDiamond morphology, Deposit - Lomonosov
DS1998-0469
1998
Garanin, V.K.Garanin, V.K., Kudriavtseva, G.P., Vasilyeva, E.R.The fundamental study of garnets: application for prospecting and economical estimation - diamond bearing7th International Kimberlite Conference Abstract, pp. 236-8.Russia, Arkangelsk, Kola PeninsulaGarnet mineralogy, Deposit - Zolitsky, Verkhotinsky
DS1998-0470
1998
Garanin, V.K.Garanin, V.K., Posukhova, T.V.Unusual diamonds from Arkhangelsk kimberlite provinceIma 17th. Abstract Vol., p. A15. poster abstractRussia, Arkangelsk, Kola PeninsulaDiamond morphology, Deposit - Pioneerskaya
DS1998-0471
1998
Garanin, V.K.Garanin, V.K., Zvezdin, A.V., Okrugin, G.V.Mineralogy of oxide minerals from Morkoka pipe kimberlites (Yakutian diamond Province): implications for diamond potential evaluation.Moscow University of Geol. Bulletin., Vol. 53, No. 4, pp. 24-36.Russia, YakutiaDeposit - Morkoka
DS1999-0563
1999
Garanin, V.K.Possoukhova, T.V., Kudryavtseva, G.P., Garanin, V.K.Diamonds and accompanying minerals from Arkangelsk kimberlite, RussiaStanley, SGA Fifth Biennial Symposium, pp. 667-70.Russia, Arkangelsk, Kola PeninsulaMineralogy, Deposit - Arkangel
DS2001-0356
2001
Garanin, V.K.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
DS2001-0357
2001
Garanin, V.K.Garanin, V.K., Kudryavtseva, Possoukhova, TikhovaTwo types of the Diamondiferous kimberlites from the Arkangelsk province, RussiaMineral deposits 21st. century, pp. 955-8.Russia, ArkangelskTectonics, Deposit - Zolotitsa
DS2001-1052
2001
Garanin, V.K.Serov, I.V., Garanin, V.K., Zinchuk, N.N., Rotman, A.Ye.Mantle sources of the kimberlite volcanism of the Siberian PlatformPetrology, Vol.9, No. 6, pp. 576-88.Russia, Siberia, YakutiaGeochemistry - major, trace, ratios, mantle metasomatism, analyses, Deposit - Middle Markha, Daldyn-Alakit, Upper Muna
DS2003-0125
2003
Garanin, V.K.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Garanin, K.V., Kudryavtseva, G.P.Xenoliths of mantle metamorphic rocks from the Diamondiferous V. Grib pipe (8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractRussia, ArkangelskDeposit - Grib
DS2003-0745
2003
Garanin, V.K.Kostrovitsky, S.I., Verichev, E.M., Garanin, V.K., Suvorova, L.V., AschepkovMegacrysts from the Grib kimberlite Arkangelsk Province8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractRussia, Kola Peninsula, ArkangelskDeposit - Grib
DS2003-1423
2003
Garanin, V.K.Verichev, E.M., Garanin, V.K., Kudryavtseva, G.P.Geology, composition, conditions of formation and technique of exploration of theGeology of Ore Deposits, Vol. 45, 4, pp. 337-361.Russia, Arkangelsk, Kola PeninsulaGenesis - Grib, comparison with Lomonosov
DS200412-0173
2003
Garanin, V.K.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Garanin, K.V., Kudryavtseva, G.P.Xenoliths of mantle metamorphic rocks from the Diamondiferous V. Grib pipe ( Arkangelsk province): petrology and genetic aspects8 IKC Program, Session 6, POSTER abstractRussia, Kola Peninsula, ArchangelMantle petrology Deposit - Grib
DS200412-1048
2004
Garanin, V.K.Kostrovitsky, S.I., Malkovets, V.G., Verichev, E.M., Garanin, V.K., Suvorova, L.V.Megacrysts from the Grib kimberlite pipe ( Arkandgelsk Province, Russia).Lithos, Vol. 77, 1-4, Sept. pp. 511-523.Russia, Archangel, Kola PeninsulaHigh chromium association, genesis
DS200412-1049
2003
Garanin, V.K.Kostrovitsky, S.I., Verichev, E.M., Garanin, V.K., Suvorova, L.V., Aschepkov, I.V., Mlovets, V., Griffin, W.L.Megacrysts from the Grib kimberlite Arkangelsk Province.8 IKC Program, Session 7, POSTER abstractRussia, Kola Peninsula, ArchangelKimberlite petrogenesis Deposit - Grib
DS200412-2054
2003
Garanin, V.K.Verichev, E.M., Garanin, V.K., Kudryavtseva, G.P.Geology, composition, conditions of formation and technique of exploration of the Vladimir Grib kimberlite pipe, a new diamond dGeology of Ore Deposits, Vol. 45, 4, pp. 337-361.Russia, Kola Peninsula, ArchangelGenesis - Grib, comparison with Lomonosov
DS200512-0026
2005
Garanin, V.K.Appollonov, V.N., Verzhak, V.V., Garanin, K.V., Garanin, V.K., Kudryavtseva, G.P., Shlykov, V.G.Saponite from the Lomonosov diamond deposit.Moscow University Geology Bulletin, Vol. 59, 2, pp. 69-84.Russia, Kola Peninsula, ArchangelGeology
DS200512-0096
2005
Garanin, V.K.Bobrov, A.V., Verichev, E.M., Garanin, V.K., Kudryavtseva, G.P.The first find of kyanite eclogite in the V. Grib kimberlite pipe ( Arkangelsk Province).Doklady Earth Sciences, Vol. 402, 4, pp. 628-631.Russia, Kola Peninsula, ArchangelEclogite
DS200712-0286
2007
Garanin, V.K.Egorov, K.N., Ramnko, E.F., Podvysotsky, V.T., Sabulukov, S.M., Garanin, V.K., Dyakonov, D.B.New dat a on kimberlite magmatism in southwestern Angola.Russian Geology and Geophysics, Vol. 48, 4, pp. 323-336.Africa, AngolaMagmatism - kimberlites
DS200812-0380
2008
Garanin, V.K.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
Garanin, V.K.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
DS200812-0561
2008
Garanin, V.K.Khachatryan, G.K., Palazhchenko, O.V., Garanin, V.K., Ivannikov, P.V., Verichev, E.M.Origin of disequilibrium diamond crystals from Parpinsky 1 kimberlite pipe using dat a from cathode luminescence and infra red spectroscopy.Moscow University Geology Bulletin, Vol. 63, 2, March-April pp. 86-94.RussiaDiamond morphology
DS200812-0839
2008
Garanin, V.K.Palazhchenko, O.V., Garanin, V.K., Galimov, E.M.Isotope and mineralogical study of diamonds from northwestern Russia.Goldschmidt Conference 2008, Abstract p.A718.Russia, Kola Peninsula, ArchangelDeposit - Lomonosov, Grib
DS200912-0372
2009
Garanin, V.K.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
DS200912-0651
2009
Garanin, V.K.Rubanova, E.V., Palazhenko, O.V., Garanin, V.K.Diamonds from the V. Grib pipe, Arkangelsk kimberlite province, Russia.Lithos, In press availableRussia, Archangel, Kola PeninsulaDeposit - Grib
DS201012-0354
2008
Garanin, V.K.Khachatryan, G.K., Palazhchenko, O.V., Garanin, V.K., Ivannikov, P.V., Verichev, E.M.Origin of disequilibrium diamond crystals from Karpinsky - 1 kimberlite pipe using dat a from cathode luminescence and infra red spectroscopy.Moscow University Geology Bulletin, Vol. 63, pp. 86-94.RussiaSpectroscopy
DS201112-0553
2011
Garanin, V.K.Kriulina, G.Yu., Garanin, V.K., Rotman, A.Ya., Kovalchuk, O.E.Pecularities of diamonds from the commercial deposits of Russia.Moscow University Geology Bulletin, Vol. 66, 3, pp. 171-183.Russia, Yakutia, Kola PeninsulaArkhangelsk, Grib, Lomonosov, Mir, Internationalnaya
DS201112-0970
2011
Garanin, V.K.Sirotkina, E.A., Bobrov, A.V., Garanin, V.K., Bovkun, A.V., Shkurskii, B.B., Korost, D.V.Pyroxene and olivine exsolution textures in majoritic garnets from the Mir kimberlitic pipe, Yakutia.Goldschmidt Conference 2011, abstract p.1885.RussiaMir
DS201212-0077
2012
Garanin, V.K.Bobrov, A.V., Sirotkina, E.A., Garanin, V.K., Bovkun, A.V., Korost, D.V., Shkurski, B.B.Majoritic garnets with exsolution textures from the Mir kimberlitic pipe ( Yakutia)Doklady Earth Sciences, Vol. 444, 1, pp. 574-578.Russia, YakutiaDeposit - Mir
DS201212-0084
2012
Garanin, V.K.Bovkun, A.V., Biller, A.Y., Skvortsova, V.L., Garanin, V.K.Polyphase hydrocarbon inclusions in garnet from the Mir pipe ( Yakutia, Russia).10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Mir
DS201212-0229
2012
Garanin, V.K.Garanin, V.K., Anashkin, S.M., Bovkun, A.V., Jelsma, H., Shmakov, I.I., Garanin, K.V.Groundmass microcrystalline oxides from the Marsfontein pipe ( RSA) , Catoca, Camachia and other Angolan kimberlite pipes.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, Angola, South AfricaDeposit - Marsfontein, Catoca, Camachia
DS201212-0438
2012
Garanin, V.K.Malkovets, V.G., Griffin, W.L., Pearson, N.J., Rezvukhin, D.I., Oreilly, S.Y., Pokhilenko, N.P., Garanin, V.K., Spetsius, Z.V., Litasov, K.D.Late metasomatic addition of garnet to the SCLM: Os-itope evidence.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractMantleMetasomatism
DS201212-0659
2012
Garanin, V.K.Sirotkina, E.A., Bobrov, A.V., Garanin, V.K., Bovkin, A.V., Shkurski, B.B., Korost, D.V.Exsolution textures in majoritic garnets from the Mir kimberlite pipe, Yakutia, Russia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, YakutiaDeposit - Mir
DS201212-0733
2012
Garanin, V.K.Tretyachenko, W., Bovkun, A.V., Garanin, K.V., Garanin, V.K., Tretyachenko, N.G.Formation features of the early Hercynic alkaline ultrabasic and basic volcanic complexes from Zimny Bereg area, north east of Archangelsk region, Russia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractRussia, Archangel, Kola PeninsulaAlkalic
DS201312-0019
2013
Garanin, V.K.Anashkin, S.M., Bovkum, A.V., Litvin, Yu.A., Garanin, V.K.the intraplate character of supercontinent tectonics.Doklady Earth Sciences, Vol. 451, 2, pp. 849-854.MantleTectonics
DS201412-0267
2014
Garanin, V.K.Garanin, V.K., Bovkun, A.V., Garanin, K.V., Kriulina, G.Y., Iwanich, W.Diamonds and its grade in different petrochemical types of kimberlites ( based on Russian diamond deposits).6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 4p. AbstractRussiaMineral chemisty
DS201412-0268
2014
Garanin, V.K.Garanin, V.K., Garanin, K.V., Iwanuch, W.Polygenesis and discreteness of diamond formation. 6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 1p. AbstractGlobalDiamond genesis
DS201412-0269
2014
Garanin, V.K.Garanin, V.K., Garanin, K.V., Iwanuch, W.Diamonds from Russia. History6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractRussiaHistory and discoveries
DS201412-0270
2014
Garanin, V.K.Garanin, V.K., Garanin, K.V., Kriulina, G.Y.Granitoids of different geochemical types of Baikal area: their diamonds from Russia.30th. International Conference on Ore Potential of alkaline, kimberlite and carbonatite magmatism. Sept. 29-, http://alkaline2014.comRussiaDiamonds
DS201412-0482
2014
Garanin, V.K.Kriulina, G.Yu., Garanin, V.K., Rotman, A.Ya., Kovalchuk, O.E.Pecularities of diamonds from the commercial deposits of Russia.Moscow University Geology Bulletin, Vol. 66, 3, pp. 171-183.Russia, Yakutia, Kola Peninsula, ArchangelDiamond Morphology
DS201506-0269
2014
Garanin, V.K.Garanin, V.K., Leybov, M.B.Diamonds: a sketch portrait (History of discovery of Russian deposits and their genesis).Mineralogical Almanac, Vol. 19, 1, pp. 30-47.RussiaHistory
DS201508-0355
2015
Garanin, V.K.Garanin, V.K.The Fersman mineralogical museum in the 21st century: past, present and future,Mineral @fmmm.ru, Vol. 18, 3, pp. 24-41.RussiaHistory - Fersman
DS201705-0828
2017
Garanin, V.K.Garanin, V.K., Kriulina, G.Y.Diamonds in Russia. ( discoveries)lithographie.org, No. 19, pp. 94-103.RussiaBook - history
DS201706-1092
2017
Garanin, V.K.Litvin, Yu.A., Bovkun, A.V., Androsova, N.A., Garanin, V.K.The system ilmenite-carbonatite-carbon in the origin of diamond: correlation between the titanium content and the diamond potential of kimberlite.Doklady Earth Sciences, Vol. 473, 1, pp. 286-290.Mantlecarbonatite

Abstract: Experimental studies of melting relations in the system ilmenite-K-Na-Mg-Fe-Ca carbonatite-carbon at 8 GPa and 1600°C provide evidence for the effect of liquid immiscibility between ilmenite and carbonatite melts. It is shown that the solubility of ilmenite in carbonatitic melts is negligible and does not depend on its concentration in experimental samples within 25-75 wt %. However, carbonatite-carbon melts are characterized by a high diamond-forming efficiency. This means that the correlation between the concentration of TiO2 and diamond content is problematic for mantle chambers and requires further, more complex, experimental studies.
DS201809-2041
2018
Garanin, V.K.Iskrina, A.V., Bobrov, A.V., Kriulina, G.Y., Zedgenizov, D.A., Garanin, V.K.Melt/fluid inclusions in diamonds from the Lomonosov deposit ( Arkangelsk kimberlite province).Goldschmidt Conference, 1p. AbstractRussia, Kola Peninsuladeposit - Lomonosov

Abstract: Melt/fluid inclusions in diamonds provide important evidence for mantle diamond-forming fluids or melts. By now, the major characteristics of the composition of microinclusions have been analyzed in diamonds from several kimberlite provinces and pipes worldwide [1-4]. Here we report the first data on the composition of parent diamondforming melts for diamonds from the Arkhangelsk kimberlite province. After the study of morphology, specialty of the internal structure, and distribution of microinclusions in diamonds, 10 single crystals were selected from the 31 diamonds of the representative collection. The studied crystals may be divided into two groups: cuboids and coated diamonds. The crystals have grayish yellow or dark gray colors and are almost nontransparent due to the high content of microinclusions. Polished slices of these diamonds were studied by IR-spectroscopy, which allowed us to calculate the content of nitrogen defects, as well as the content of water and carbonates in microinclusions. X-ray spectral analyses allowed to study the composition of fluid/melt microinclusions and showed that they were essentially carbonate-silicate with significant variations between these two end-members. All inclusions contain water, with the highest H2O/CO2 in highly siliceous inclusions. Unlike diamonds from Canada and South Africa [1, 2], the studied inclusions in diamionds from the Arkhangelsk province are almost free of chlorides. Comparison of the data obtained with the database on fliud/melt inclusions in diamonds worldwide shows similar of Arkhangelsk diamonds to some diamonds from Yakutia [3, 4], and the data obtained are the most similar to the composition of microinclusions in diamonds from the Internatsionalnaya pipe (Yakutia).
DS201810-2346
2018
Garanin, V.K.Litvin, Yu.A., Kuzyura, A.V., Varlamov, D.A., Bovkun, A.V., Spival, A.V., Garanin, V.K.Interaction of kimberlite magma with diamonds upon uplift from the upper mantle to the Earth's crust.Geochemistry International, Vol. 56, 9, pp. 881-900.Russiadeposit - Nyurbinskaya

Abstract: Interaction between a melt of kimberlite from the Nyurbinskaya pipe (Yakutia) and natural monocrystalline diamonds was studied experimentally at 0.15 GPa and 1200-1250°C in high-pressure and high-temperature Ar gas “bombs.” The loss of diamond weight with slight surface dissolution of diamonds in a Ca carbonate-bearing kimberlite melt over the course of 2 h (the period of kimberlite transport from upper-mantle diamond-forming chambers to the crustal cumulative centers) is 3-4.5%. In 4 and 7-8 days (under the conditions of crustal cumulative centers), the weight of diamond decreases with remarkable bulk dissolution by 13.5 and 24.5-27.5%, respectively. In the run at 0.15 GPa and 1200°C kimberlite and ilmenite (added) melts interact to produce perovskite melt. Both of the melts, rich in titanium minerals, are immiscible with kimberlite melt and therefore cannot influence the diamond dissolution kinetics in the kimberlite melt. The experimental results suggest that precisely the dissolution processes for thermodynamically metastable diamonds in silicate-carbonate kimberlitic magmas are responsible for the effective decrease in the diamond potential of kimberlite deposits. The paper discusses the physicochemical reasons for the decrease in the kimberlite diamond potential during the chemically active history of diamond genesis: from upper-mantle chambers to the explosive release of diamonds and kimberlite material from cumulative centers to the Earth’s surface. The data on experimental physicochemical studies of the origin, analytical mineralogy of inclusions, and isotope geochemistry of diamonds are correlated.
DS201909-2054
2019
Garanin, V.K.Kriulina, G.Yu., Vasiliev, E.A., Garanin, V.K.Structural and mineralogical features of diamonds from the Lomonosov deposit ( Arkhangelsk Province): new data and interpretation.Doklady Earth Sciences, Vol. 486, 2, pp. 627-629.Russia, Archangeldeposit - Lomonosov

Abstract: Three groups of diamond crystals that differ in morphology, photoluminescence, infrared absorption, and thermal history were discovered in the Lomonosov deposit. The first group crystals are mostly octahedrons with minor signs of dissolution and a large share of nitrogen in the form of B defects. The crystals of the second type are strongly resorbed dodecahedroids with a small share of B defects. The third group consists of crystals with low-temperature ? defects; they are cuboids that are often without traces of resorption, and tetrahexahedroids. These patterns indicate the polygenicity of the diamond in the Lomonosov deposit.
DS201910-2275
2019
Garanin, V.K.Kriulina, G.Yu., Iskrina, A.V., Zedgenizov, D.A., Bobrov, A.V., Garanin, V.K.The compositional pecularities of microinclusions in diamonds from the Lomonosov deposit ( Arkangelsk Province).Geochemistry International, Vol. 57, 9, pp. 963-980.Russiadeposit - Lomonosov

Abstract: The data on the composition of microinclusions in diamonds from the Lomonosov deposits are reported for the first time. The studied diamonds include “coated” (n = 5) and cubic (n = 5) crystals. The estimated range of the degree of nitrogen aggregation in diamonds (4-39% B1) does not support their direct links with kimberlite magmatism; however, their short occurrence in the mantle at higher temperatures is probable as well. The composition of melt/fluid microinclusions in these samples varies from essentially carbonatitic to significantly silicate. It is shown that the contents of MgO, CaO, Na2O, Cl, and P2O5 decrease with increasing content of silicates and water. Different mechanisms of the generation and evolution of diamond-forming media are discussed to explain the observed variations.
DS202008-1457
2020
Garanin, V.K.Vorobei, S.S., Garanin, V.K., Minervina, E.A., Posukhova, T.V., Weisheng, X.The mineralogy and geochemistry of mantle xenoliths from diamondiferous kimberlite of China and Russia.Moscow University Geology Bulletin, Vol. 75, 2, pp. 128-135. pdfRussia, Chinadeposit - Mir, Shandong, Liaoning

Abstract: enoliths from the Mir pipe and from the Shandong and Liaoning provinces were studied by the methods of EMPA and ICP-MS. Their mineralogical, geochemical, and genetic features were revealed. Minerals of diamondiferous paragenesis were detected in xenoliths from the Mir pipe, while they were not found in xenoliths of China. All xenoliths are characterized by secondary alterations, which are more intense in xenoliths of China. The distribution of REEs shows the involvement of subduction processes in the formation of xenoliths from the Mir pipe. The influence of metasomatism is clearly evident in xenoliths from China. The calculated P-T parameters (? = 600-700°C, P = 2-2.5 GPa) are not consistent with the mantle environments that correspond to the metasomatic conditions.
DS202010-1840
2020
Garanin, V.K.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.
DS202204-0541
2022
Garanin, V.K.Vasilev, E.A., Kriulina, G.Yu., Garanin, V.K.Spectroscopy of diamond from the M.V. Lomonosov deposit.Geology of Ore Deposits, Vol. 63, 7, pp. 668-674.Russia, Kola Peninsuladeposit - Lomonosov

Abstract: Diamond crystals from the M.V. Lomonosov deposit (Archangelsk oblast, Russia) were studied by luminescence and infrared spectroscopy. Three groups of crystals were distinguished according to their morphology, thermal history, and photoluminescence. The structural diversity of yellow cuboids typical for the deposit is demonstrated. New photoluminescence systems among the low-temperature cuboid crystals are observed.
DS202205-0725
2021
Garanin, V.K.Vasilev, E., Kriulina, G.Y., Garanin, V.K.Spectroscopy of diamonds from the M.V. Lomonosov deposit.Geology of Ore deposits, Vol. 63, pp. 668-684. pdfRussiadeposit - Lomonosov

Abstract: Diamond crystals from the M.V. Lomonosov deposit (Archangelsk oblast, Russia) were studied by luminescence and infrared spectroscopy. Three groups of crystals were distinguished according to their morphology, thermal history, and photoluminescence. The structural diversity of yellow cuboids typical for the deposit is demonstrated. New photoluminescence systems among the low-temperature cuboid crystals are observed.
DS201212-0177
2012
Garanin, VK.Dyakonov, D.B., Garanin, VK., Garanin, K.V., Bushueva, E.B., Enalieva, M.A., Wedensky, E.S.Searching for new diamond deposits in western Liberia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, LiberiaProspects - Yambassen, Kumgbo
DS1980-0136
1980
Garanin, Y.K.Garanin, Y.K.Typical Features of Ilmenite from Kimberlites, Alkali Ultrabasic Intrusions and Carbonatites.International Geology Review, Vol. 22, No. 9, PP. 1024-1050.RussiaGeochemistry
DS1989-0472
1989
Garanin, Ye.V.Garanin, Ye.V., Guseva, Ye.V., Dergachev, D.V., Kudryatseva, G.P.Diamond crystals in garnets from slightly gneissic graniteDoklady Academy of Science USSR, Earth Science Section, Vol. 298, No. 1-6, April pp. 92-96RussiaDiamond morphology, Gneiss, Garnet analyses
DS201312-0295
2013
Garapic, G.Garapic, G., Faul, U.H., Brisson, E.High resolution imaging of the melt distribution in partially molten upper mantle rocks: evidence for wetted two grain boundaries.Geochemistry, Geophysics, Geosystems: G3, Vol. 14, 3, pp. 556-566.MantleMelting
DS2001-1013
2001
GaratSarayev, A.L., Pertel, Garat, Manakov, AlexandrovPossibilities of magnetotellurics for kimberlite exploration in the Russian PlatformNorth Atlantic Minerals Symposium held May 27-30, pp. 149. abstract.RussiaGeophysics - magnetotellurics
DS200512-0344
2005
GaratGladkov, 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
DS200912-0243
2009
Garat, J.Garat, J., Haggerty, S.E., Rekhi, S., Chance, M.Infrared absorption investigations confirm the extraterrestrial origin of carbonado diamonds.The Astrophysical Journal, Vol. 653, L153-156.Africa, Central African Republic, South America, BrazilCarbonado
DS1993-0485
1993
Garat, M.N.Garat, M.N.The application of geophysical investigations in drill holes for kimberlite prospecting in the covered areas of western Yakutia.Diamonds of Yakutia, pp. 133-134.Russia, YakutiaGeophysics
DS200512-0935
2002
Garat, M.N.Saraev, A.K., Pertel, M.I., Nikiforov, A.B., Garat, M.N., Manakov, A.B., Ingerov, O.I.Magnetotelluric exploration for kimberlite pipes in Yakutian Province, Sakha Republic, Russia.Phoenix Geophysics Preprint, English, Jan. 7p. text 17 figuresRussia, Siberia, YakutiaGeophysics - magnetotellurics, Almakinskaya, Mirensky
DS1994-0574
1994
Garbar, D.I.Garbar, D.I.Tectonics and prospects for diamonds of the northwestern part of the east European Platform10th. Prospecting In Areas Of Glaciated Terrain, pp. 153-154. AbstractRussia, KareliaGeotectonics, Exploration prospecting
DS201012-0008
2010
Garbarino, G.Andrault, D., Nigro, G., Bolfan-Casanova, N., Bouhifd, M.A., Garbarino, G., Mezouar, M.Melting curve of the lowermost Earth's mantle.Goldschmidt 2010 abstracts, abstractMantleMelting
DS201112-0020
2011
Garbarino, G.Andrault, D., Bolfan-Casanova, N., loNigro, G., Bouhifd, M.A., Garbarino, G., Mezouar, M.Solidus and liquidus profiles of chrondritic mantle: implications for melting of the Earth across its history.Earth and Planetary Science Letters, Vol. 304, 1-2, pp. 251-259.MantleMelting
DS201112-0021
2011
Garbarino, G.Andrault, D., Lo Nigro, G., Bolfan-Casanova, N., Bouhifd, M.A., Garbarino, G., Mezouar, M.Melting properties of chronditic mantle to the core mantle boundary.Goldschmidt Conference 2011, abstract p.438.MantleMelting
DS201112-0321
2011
Garbarino, G.Fiquet, G., Auzende, A.L., Siebert, J., Corgne, A., Bureau, H., Ozawa, H., Garbarino, G.Melting of peridotite to 140 GPa.Goldschmidt Conference 2011, abstract p.848.MantleGeotherms
DS201711-2499
2017
Garbarino, G.Andrault, D., Bolfan-Casanova, N., Bouhifd, M.A., Boujibar, A., Garbarino, G., Manthilake, G., Mezouar, M., Monteux, J., Parisiades, P., Pesce, G.Toward a coherent model for the melting behaviour of the deep Earth's mantle.Physics of the Earth and Planetary Interiors, Vol. 265, pp. 67-81.Mantlemelting

Abstract: Knowledge of melting properties is critical to predict the nature and the fate of melts produced in the deep mantle. Early in the Earth’s history, melting properties controlled the magma ocean crystallization, which potentially induced chemical segregation in distinct reservoirs. Today, partial melting most probably occurs in the lowermost mantle as well as at mid upper-mantle depths, which control important aspects of mantle dynamics, including some types of volcanism. Unfortunately, despite major experimental and theoretical efforts, major controversies remain about several aspects of mantle melting. For example, the liquidus of the mantle was reported (for peridotitic or chondritic-type composition) with a temperature difference of ?1000 K at high mantle depths. Also, the Fe partitioning coefficient (DFeBg/melt) between bridgmanite (Bg, the major lower mantle mineral) and a melt was reported between ?0.1 and ?0.5, for a mantle depth of ?2000 km. Until now, these uncertainties had prevented the construction of a coherent picture of the melting behavior of the deep mantle. In this article, we perform a critical review of previous works and develop a coherent, semi-quantitative, model. We first address the melting curve of Bg with the help of original experimental measurements, which yields a constraint on the volume change upon melting (?Vm). Secondly, we apply a basic thermodynamical approach to discuss the melting behavior of mineralogical assemblages made of fractions of Bg, CaSiO3-perovskite and (Mg,Fe)O-ferropericlase. Our analysis yields quantitative constraints on the SiO2-content in the pseudo-eutectic melt and the degree of partial melting (F) as a function of pressure, temperature and mantle composition; For examples, we find that F could be more than 40% at the solidus temperature, except if the presence of volatile elements induces incipient melting. We then discuss the melt buoyancy in a partial molten lower mantle as a function of pressure, F and DFeBg/melt. In the lower mantle, density inversions (i.e. sinking melts) appear to be restricted to low F values and highest mantle pressures. The coherent melting model has direct geophysical implications: (i) in the early Earth, the magma ocean crystallization could not occur for a core temperature higher than ?5400 K at the core-mantle boundary (CMB). This temperature corresponds to the melting of pure Bg at 135 GPa. For a mantle composition more realistic than pure Bg, the right CMB temperature for magma ocean crystallization could have been as low as ?4400 K. (ii) There are converging arguments for the formation of a relatively homogeneous mantle after magma ocean crystallization. In particular, we predict the bulk crystallization of a relatively large mantle fraction, when the temperature becomes lower than the pseudo-eutectic temperature. Some chemical segregation could still be possible as a result of some Bg segregation in the lowermost mantle during the first stage of the magma ocean crystallization, and due to a much later descent of very low F, Fe-enriched, melts toward the CMB. (iii) The descent of such melts could still take place today. There formation should to be related to incipient mantle melting due to the presence of volatile elements. Even though, these melts can only be denser than the mantle (at high mantle depths) if the controversial value of DFeBg/melt is indeed as low as suggested by some experimental studies. This type of melts could contribute to produce ultra-low seismic velocity anomalies in the lowermost mantle.
DS1985-0738
1985
Garbausk, M.F.Wong, J., Koch, E.F., Hejna, C.L., Garbausk, M.F.Atomic and Microstructural Characterization of Metal Impurities in Synthetic Diamonds.Journal of APPLIED PHYSICS, Vol. 58, No. 9, Nov. 1, PP. 3388-3393.GlobalSynthetic Diamond
DS1985-0737
1985
Garbauskas, M.F.Wong, J., Koch, E.F., Hejna, C.I., Garbauskas, M.F.Atomic and microstructural characterization of metal impurities in synthetic diamondsJournal of Applied Physics, Vol. 58, No. 9, Nov. 1, pp. 3388-3393GlobalDiamond Morphology
DS1860-0381
1882
GarbeGarbeDie Indischen MineralienUnknown., IndiaGemology
DS1995-0428
1995
Garber, D.I.Dobrynina, M.I., Alexandrov, S.P., Garber, D.I.Kimberlites of the Arkhangelsk diamond province review of their structuralsetting, petrophysical characters.American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, No. 95-151, 6p.Russia, ArkangelskStructure, Deposit -Arkhangel
DS201807-1491
2018
Garber, J.M.Garber, J.M., Maurya, S., Hernandez, J-A., Duncan, M.S., Zeng, Li., Zhang, H.L., Faul, U., McCammon, C., Montagner, J-P., Moresi, L., Romanowicz, B.A., Rudnick, R.L., Stixrude, L.Multidisciplinary constraints on the abundance of diamond and eclogite in the cratonic lithosphere. Mentions Jericho and Roberts VictorGeochemistry, Geophysics, Geosystems, https://doi.org/10.1029/2018GCC007534Globalthermobarometry

Abstract: Some seismic models derived from tomographic studies indicate elevated shear?wave velocities (?4.7 km/s) around 120?150 km depth in cratonic lithospheric mantle. These velocities are higher than those of cratonic peridotites, even assuming a cold cratonic geotherm (i.e., 35 mW/m2 surface heat flux) and accounting for compositional heterogeneity in cratonic peridotite xenoliths and the effects of anelasticity. We reviewed various geophysical and petrologic constraints on the nature of cratonic roots (seismic velocities, lithology/mineralogy, electrical conductivity, and gravity) and explored a range of permissible rock and mineral assemblages that can explain the high seismic velocities. These constraints suggest that diamond and eclogite are the most likely high?Vs candidates to explain the observed velocities, but matching the high shear?wave velocities requires either a large proportion of eclogite (>50 vol.%) or the presence of up to 3 vol.% diamond, with the exact values depending on peridotite and eclogite compositions and the geotherm. Both of these estimates are higher than predicted by observations made on natural samples from kimberlites. However, a combination of ?20 vol.% eclogite and ~2 vol.% diamond may account for high shear?wave velocities, in proportions consistent with multiple geophysical observables, data from natural samples, and within mass balance constraints for global carbon. Our results further show that cratonic thermal structure need not be significantly cooler than determined from xenolith thermobarometry.
DS201808-1745
2018
Garber, J.M.Garber, J.M., Maurya, S., Hernandez, J-A., Duncan, M.S., Zeng, L., Zhang, H.L., Faul, U., McCammon, C., Montagner, J-P., Moresi, L., Romanowicz, B.A., Rudnick, R.L., Stixrude, L.Multidisciplinary constraints on the abundance of diamond and eclogite in the cratonic lithosphere.G3 Geochemistry, Geophysics, Geosystems, http:/orchid.org/0000-0001-5313-0982Mantleeclogite
DS201809-2024
2018
Garber, J.M.Garber, J.M., Maurya, S., Hernandez, J.A., Duncan, M.S., Zeng, L., Zhang, H.L.Multidisciplanary constraints on the abundance of diamond and eclogite in the cratonic lithosphere.Geochemistry, Geophysics, Geosystems, Vol. 19, 7, pp. 2062-2086. doi.org/10/1029/ 2018GC007534Mantlegeophysics - seismics

Abstract: Some seismic models derived from tomographic studies indicate elevated shear?wave velocities (?4.7 km/s) around 120-150 km depth in cratonic lithospheric mantle. These velocities are higher than those of cratonic peridotites, even assuming a cold cratonic geotherm (i.e., 35 mW/m2 surface heat flux) and accounting for compositional heterogeneity in cratonic peridotite xenoliths and the effects of anelasticity. We reviewed various geophysical and petrologic constraints on the nature of cratonic roots (seismic velocities, lithology/mineralogy, electrical conductivity, and gravity) and explored a range of permissible rock and mineral assemblages that can explain the high seismic velocities. These constraints suggest that diamond and eclogite are the most likely high?Vs candidates to explain the observed velocities, but matching the high shear?wave velocities requires either a large proportion of eclogite (>50 vol.%) or the presence of up to 3 vol.% diamond, with the exact values depending on peridotite and eclogite compositions and the geotherm. Both of these estimates are higher than predicted by observations made on natural samples from kimberlites. However, a combination of ?20 vol.% eclogite and ~2 vol.% diamond may account for high shear?wave velocities, in proportions consistent with multiple geophysical observables, data from natural samples, and within mass balance constraints for global carbon. Our results further show that cratonic thermal structure need not be significantly cooler than determined from xenolith thermobarometry.
DS202004-0499
2020
Garber, J.M.Aulbach, S., Masuyeau, M., Gerdes, A., Garber, J.M.Ultramafic carbonated melt- and-auto -metasomatism in mantle eclogites: compositional effects and geophysical consequences.Geochemistry, Geophysics, Geosystems, in press available, 41p. PdfMantleeclogites
DS202009-1628
2018
Garber, J.M.Garber, J.M., Maurya, S., Hernandez, J.A., Duncan, M.S., Zeng, L., Zhang, H.L.Multidisciplenary constraints on the abundance of diamond and eclogite in the cratonic lithosphere.Geochemistry, Geophysics, Geosystems, Vol. 19: https://doi.org/10.1029/2018GC007534Mantleeclogite

Abstract: Some seismic models derived from tomographic studies indicate elevated shear?wave velocities (?4.7 km/s) around 120-150 km depth in cratonic lithospheric mantle. These velocities are higher than those of cratonic peridotites, even assuming a cold cratonic geotherm (i.e., 35 mW/m2 surface heat flux) and accounting for compositional heterogeneity in cratonic peridotite xenoliths and the effects of anelasticity. We reviewed various geophysical and petrologic constraints on the nature of cratonic roots (seismic velocities, lithology/mineralogy, electrical conductivity, and gravity) and explored a range of permissible rock and mineral assemblages that can explain the high seismic velocities. These constraints suggest that diamond and eclogite are the most likely high?Vs candidates to explain the observed velocities, but matching the high shear?wave velocities requires either a large proportion of eclogite (>50 vol.%) or the presence of up to 3 vol.% diamond, with the exact values depending on peridotite and eclogite compositions and the geotherm. Both of these estimates are higher than predicted by observations made on natural samples from kimberlites. However, a combination of ?20 vol.% eclogite and ~2 vol.% diamond may account for high shear?wave velocities, in proportions consistent with multiple geophysical observables, data from natural samples, and within mass balance constraints for global carbon. Our results further show that cratonic thermal structure need not be significantly cooler than determined from xenolith thermobarometry.
DS2002-0728
2002
GarbeSchonbergHoenle, K., Tilton, G., LeBas, Duggen, GarbeSchonbergGeochemistry of oceanic carbonatites compared with continental carbonatites; mantle recycling of oceanic..Contribution to Mineralogy and Petrology, Vol.142, 5, pp.520-42.Mantle, OceanicCarbonatite - recycling crustal carbonate
DS2002-0729
2002
Garbe-SchonbergHoernle, K., Tilton, Le Bas, Duggen, Garbe-SchonbergGeochemistry of oceanic carbonatites compared with continental carbonatites: mantle recycling of oceanic..Contributions to Mineralogy and Petrology, Vol. 142, No. 5, Feb. pp. 520-42.MantleGeochemistry, Carbonatite - crustal carbonate
DS201112-0439
2011
Garbe-SchonbergHoffmann, J.E., Munker, C., Naeraa, T., Rosing, M.T., Herwartz, D., Garbe-Schonberg, Svahnberg, H.Mechanisms of Archean crust formation inferred from high precision HFSE systematics in TTGs.Geochimica et Cosmochimica Acta, Vol. 75, 15, pp. 4157-4178.Europe, GreenlandMantle melting
DS200612-0723
2006
Garbe-Schonberg, D.Kokfelt, T.F., Hoernle, K., Hauff, F., Fiebig, J., Werner, R., Garbe-Schonberg, D.Combined trace element and Pb Nd Sr and O isotope evidence for recycled oceanic crust ( upper and lower) in the Iceland mantle plume.Journal of Petrology, Vol. 47, 9, Sept. pp. 1705-1749.Europe, IcelandGeochronology, subduction
DS201605-0903
2016
Garbe-Schonberg, D.Sobolev, A.V., Asafov, E.V., Gurenko, A.A., Arndt, N.T., Batanova, V.G., Portnyagin, M.V., Garbe-Schonberg, D., Krasheninnikov, S.P.Komatites reveal a hydrous Archaen deep mantle reservoir.Nature, Vol. 531, Mar. 31, pp. 628-632.MantleMelting

Abstract: Archaean komatiites (ultramafic lavas) result from melting under extreme conditions of the Earth’s mantle. Their chemical compositions evoke very high eruption temperatures, up to 1,600 degrees Celsius, which suggests even higher temperatures in their mantle source1, 2. This message is clouded, however, by uncertainty about the water content in komatiite magmas. One school of thought holds that komatiites were essentially dry and originated in mantle plumes3, 4, 5, 6 while another argues that these magmas contained several per cent water, which drastically reduced their eruption temperature and links them to subduction processes7, 8, 9. Here we report measurements of the content of water and other volatile components, and of major and trace elements in melt inclusions in exceptionally magnesian olivine (up to 94.5?mole per cent forsterite). This information provides direct estimates of the composition and crystallization temperature of the parental melts of Archaean komatiites. We show that the parental melt for 2.7-billion-year-old komatiites from the Abitibi greenstone belt in Canada contained 30 per cent magnesium oxide and 0.6 per cent water by weight, and was depleted in highly incompatible elements. This melt began to crystallize at around 1,530 degrees Celsius at shallow depth and under reducing conditions, and it evolved via fractional crystallization of olivine, accompanied by minor crustal assimilation. As its major- and trace-element composition and low oxygen fugacities are inconsistent with a subduction setting, we propose that its high H2O/Ce ratio (over 6,000) resulted from entrainment into the komatiite source of hydrous material from the mantle transition zone10. These results confirm a plume origin for komatiites and high Archaean mantle temperatures, and evoke a hydrous reservoir in the deep mantle early in Earth’s history.
DS201806-1227
2018
Garbe-Schonberg, D.Homrighausen, S., Hoernle, K., Hauff, J., Geldmacher, J., Garbe-Schonberg, D.Global distribution of the HIMU end member: formation through Archean plume lid tectonics.Earth Science Reviews, Vol. 182, pp. 85-101.Globaltectonics

Abstract: Oceanic basalts reflect the heterogeneities in the earth's mantle, which can be explained by five mantle end members. The HIMU end member, characterized by high time-integrated ? (238U/204Pb), is defined by the composition of lavas from the ocean islands of St. Helena, South Atlantic Ocean and Mangaia and Tubuai (Cook-Austral Islands), South Pacific Ocean. It is widely considered to be derived from a mantle reservoir that is rarely sampled and not generally involved in mixing with the other mantle components. On the other hand, the FOZO end member, located at the FOcal ZOne of oceanic volcanic rock arrays on isotope diagrams, is considered to be a widespread common component with slightly less radiogenic 206Pb/204Pb and intermediate Sr-Nd-Hf isotopic compositions. Here we present new major and trace element, Sr-Nd-Pb-Hf isotope and geochronological data from the Walvis Ridge and Richardson Seamount in the South Atlantic Ocean and the Manihiki Plateau and Eastern Chatham Rise in the southwest Pacific Ocean. Our new data, combined with literature data, document a more widespread (nearly global) distribution of the HIMU end member than previously postulated. Our survey shows that HIMU is generally associated with low-volume alkaline, carbonatitic and/or kimberlitic intraplate volcanism, consistent with derivation from low degrees of melting of CO2-rich sources. The majority of end member HIMU locations can be directly related to hotspot settings. The restricted trace element and isotopic composition (St. Helena type HIMU), but near-global distribution, point to a deep-seated, widespread reservoir, which most likely formed in the Archean. In this context we re-evaluate the origin of a widespread HIMU reservoir in an Archean geodynamic setting. We point out that the classic ocean crust recycling model cannot be applied in a plume-lid dominated tectonic setting, and instead propose that delamination of carbonatite-metasomatized subcontinental lithospheric mantle could be a suitable HIMU source.
DS201907-1527
2019
Garbe-Schonberg, D.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.
DS201907-1576
2019
Garbe-Schonberg, D.Sobolev, A.V., Asafov, E., Arndt, N., Portnyagin, M., Guenko, A.A., Batanova, G., Garbe-Schonberg, D., Wilson, A.H., Byerly, G., Batanova, V.Deep hydrous mantle reservoir provides evidence for crustal recycling before 3.3 billion years ago.Nature, 32p. Pdf availableMantlewater

Abstract: H2O strongly influences physical properties of the mantle and its ability to melt or convect and can trace recycling of surface reservoirs down to the deep mantle1,2. This makes knowledge of water content in the Earth's interior and its evolution through time crucial to understanding global geodynamics. Komatiites (MgO-rich ultramafic magmas) result from high-degree mantle melting at high pressures3 and thus are excellent probes of H2O contents in the deep mantle. A significant excess of H2O over elements of similar geochemical behavior during mantle melting (e.g. Ce) was recently found in melt inclusions in the most Mg-rich olivine in 2.7 Ga old komatiites from Canada4 and Zimbabwe5. These data were taken as evidence for a deep hydrated mantle reservoir, probably the transition zone, in the Neoarchean time. In this paper we confirm the mantle source of this H2O by measurement of deuterium to hydrogen ratios in these melt inclusions and present similar data for 3.3 Ga old komatiites from the Barberton Greenstone Belt. Using hydrogen isotopes, we show that the mantle sources of these melts contained excess H2O which implies that a deep mantle hydrated reservoir has been present in the Earth's interior at least since the Paleoarchean. The reconstructed initial hydrogen isotope composition of komatiites is significantly more depleted in deuterium than all surface reservoirs and typical mantle but resembles that in dehydrated subducted slabs. Together with a significant excess of chlorine and a temporal trend of Pb/Ce in the mantle sources of komatiites, these results argue that lithosphere recycling into the deep mantle, arguably via subduction, started before 3.3 Ga. (a un-reviewed version of the manuscript accepted for publication in Nature magazine).
DS200612-0748
2006
Garces, M.Kuiper, K.F., Krijgsman, W., Garces, M., Wijbrans, J.R.Revised isotopic (40 Ar 29 Ar) age for the lamproite volcano of Cabezos Negros, Fortuna Basin, eastern Beltics, SE Spain).Paleogeography Paleoclimatology Paleoecology, Vol. 238, 1-4, pp. 53-63.Europe, SpainLamproite
DS2001-0670
2001
GarciaLee, M.J., Garcia, Moutte, Wall, Williams, WoolleyPyrochlore chemistry and the transition from Calcium carbonatites and phoscorites to magnesium-iron carbonatites..Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 24 (abs)FinlandCarbonatite, Sokli Complex
DS200912-0341
2009
GarciaJones, A.G., Evans, Muller, Hamilton, Miensopust, Garcia, Cole, Ngwisanyi, Hutchins, Stoffel Fourie, Jelsma, Aravanis, Petit, Webb, WasborgArea selection for diamonds using magnetotellurics: examples from southern Africa.Lithos, In press - available 35p.Africa, South Africa, BotswanaGeophysics - magnetotellurics
DS200912-0522
2009
GarciaMuller, M.R., Jones, Evans, Grutter, Hatton, Garcia, Hamilton, Miensopust, Cole, Ngwisanyi, Hutchins, Fourie, Jelsma,Aravanis.Pettit, Webb, WasborgLithospheric structure, evolution and diamond prospectivity of the Rehoboth Terrane and western Kaapvaal Craton, southern Africa: constraints from broadbandLithos, In press - available 57p..Africa, South Africa, BotswanaGeophysics - broadband magnetotellurics
DS200812-0812
2008
Garcia, A.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
DS202103-0413
2021
Garcia, C.A.Stoudmann, N., Reibelt, L.M., Rakotomalala, A.G., Randriamanjakahasina, O., Garcia, C.A., Waeber, P.O.A double edged sword: realities of artisanal and small scale mining for rural people in the Alaotra region of Madagascar. ** not specific to diamondsNatural Resources Forum, Vol 45 pp. 87-102. pdfAfrica, Madagascaralluvials

Abstract: A growing number of people are entering the artisanal and small?scale mining (ASM) sector worldwide. In Madagascar, millions of individuals depend on this informal activity. Through a case study in the Alaotra?Mangoro region of Madagascar, our research aimed to understand the "bottom?up" dynamics and ripple effects of the sector, by looking at the realities for rural communities where inhabitants are both directly and indirectly affected by ASM. We were interested in community members' and miners' perceptions of the socio?economic and environmental impacts of ASM, and in identifying the factors attracting people living in one of the country's agricultural hubs to this activity. Our results show a wide diversity of push and pull factors leading people to enter the sector. Although many positive impacts of ASM exist for miners and communities within the vicinity of mines, most miner participants considered themselves worse off since starting to mine, highlighting the high risk and low probability of return of ASM. ASM's potential for local and national development will remain squandered if its negative impacts continue to go unmanaged. Accounting for local contexts and the ripple effects of ASM will be crucial in achieving safety and security for miners, and to tap into the benefits it may offer communities while minimising environmental damage.
DS1995-2076
1995
Garcia, D.Woolley, A.R., Williams, C.T., Wall, F., Garcia, D., MouteThe Bingo Carbonatite -ijolite - nepheline syenite complex Zaire: petrography, mineralogy ...Journal of African Earth Sciences, Vol. 21, No. 3, October pp. 329-348.Democratic Republic of CongoCarbonatite, Deposit -Bingo
DS1999-0403
1999
Garcia, D.Lee, M.J., Garcia, D., Moutte, Wall, Williams, WoolleyPyrochlore and whole rock chemistry of carbonatites and phoscorites at Sokli Finland.Stanley, SGA Fifth Biennial Symposium, pp. 651-4.FinlandCarbonatite, Deposit - Sokli
DS2003-0786
2003
Garcia, D.Lee, Mi Jung, Garcia, D., Moutte, J., Lee, J.K.Phlogopite and tetraferri phlogopite from phoscorite and carbonatite associations in theGeosciences Journal, Vol. 7, 1, March pp. 9-20.FinlandCarbonatite, Deposit - Sokli
DS200412-1104
2003
Garcia, D.Lee, Mi Jung, Garcia, D., Moutte, J., Lee, J.K.Phlogopite and tetraferri phlogopite from phoscorite and carbonatite associations in the Sokli Massif, northern Finland.Geosciences Journal, Vol. 7, 1, March pp. 9-20.Europe, FinlandCarbonatite, Deposit - Sokli
DS200612-0785
2006
Garcia, D.Lee, M.J., Lee, J.I., Garcia, D., Moutte, J., Williams, C.T., Wall, F., Kim, Y.Pyrochlore chemistry from the Sokli phoscorite carbonatite complex, Finland: implications for the genesis of phoscorite and carbonatite association.Geochemical Journal, Vol. 40, 1, pp. 1-14.Europe, FinlandCarbonatite
DS200412-0920
2004
Garcia, J.A.Johnson, N., Lilja, N., Ashby, J.A., Garcia, J.A.The practice of participatory research and gender analysis in natural resource management.Natural Resources Forum, Vol. 28, 3, pp. 189-200.GlobalResource management - not specific to diamonds
DS2002-0405
2002
Garcia, J.P.Dromart, G., Garcia, J.P., Allemand, Gaumet, RouselleA volume based approach to calculation of ancient carbonate accumulationsJournal of Geology, Vol.110,1,pp. 195-210.GlobalCarbonate - overview deposit rates, Phanerozoic - exogenic systems
DS202002-0186
2020
Garcia, L.F.Garcia, L.F., Abel, M., Perrin, M., dos Santis Alvarenga, R.The GeoCore ontology: a core ontology for general use in geology.Computers and Geosciences, Vol. 135, 104387 9p. PdfGlobalGeoCore

Abstract: Domain ontologies assume the role of representing, in a formal way, a consensual knowledge of a community over a domain. This task is especially difficult in a wide domain like Geology, which is composed of diversified science resting on a large variety of conceptual models that were developed over time. The meaning of the concepts used by the various professionals often depends on the particular vision that they have of a domain according to their background and working habits. Ontology development in Geology thus necessitates a drastic elucidation of the concepts and vocabulary used by geologists. This article intends to contribute to solving these difficulties by proposing a core ontology named GeoCore Ontology resting on the BFO top ontology, specially designed for describing scientific fields. GeoCore Ontology contains well-founded definitions of a limited set of general concepts within the Geology field that are currently considered by all geologists whatever their skill. It allows modelers to separately consider a geological object, the substance that constitutes it, the boundaries that limit it and the internal arrangement of the matter inside it. The core ontology also allows the description of the existentially dependent qualities attached to a geological object and the geological process that generated it in a particular geological age. This small set of formally defined and described concepts combined with concepts from BFO provides a backbone for deriving by subsumption more specialized geological concepts and also constitutes a baseline for integrating different existent domain ontologies within the Geology domain. The GeoCore ontology and the methodology that we used for building it, provide solutions for unveiling major misunderstanding regarding the concepts that are commonly used for formulating geological interpretations. This will facilitate the communication of this information to external Geology users and its integration in domain applications.
DS200712-0715
2007
Garcia, M.D.M.Menezes, P.T.L., Garcia, M.D.M.Kimberlite exploration at Serra da Canastra province, Brazil.Geophysics, Vol. 72, 3, May-June pp. M1-5.South America, BrazilGeophysics - magnetics
DS200912-0666
2009
Garcia, M.M.Sarava dos Santos, T.J., Garcia, M.M., Amarai, W.S., Caby, R., Wernick, E., Arthaud, M.H., Dantas, E.L., Santosh, M.Relics of eclogite facies assemblages in the Ceara central domain, NW Borborema Province, NE Brazil: implications for the assembly of West Gondwana.Gondwana Research, Vol. 15, 3-4, pp. 454-470.South America, BrazilTectonics
DS1986-0267
1986
Garcia, M.O.Garcia, M.O., Frey, F.A., Grooms, D.G.Petrology of volcanic rocks from Kaula Island Hawaii. Implications for The origin of Hawaiian phonolitesContributions to Mineralogy and Petrology, Vol. 94, No. 4, pp. 461-471HawaiiBasanite, rare earth elements (REE).
DS1986-0268
1986
Garcia, M.O.Garcia, M.O., Presti, A.A.Mantle metasomatism of pyroxenite xenoliths from Kaula Island, HawaiiProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 241-243HawaiiBlank
DS1986-0535
1986
Garcia, M.O.Matson, D.W., Muenow, D.W., Garcia, M.O.Volatile contents of phlogopite micas from South African kimberliteContributions to Mineralogy and Petrology, Vol. 93, No. 3, pp. 399-408South AfricaPetrology
DS1990-1073
1990
Garcia, M.O.Muenow, D.W., Garcia, M.O., Aggrey, K.E., Bednarz, U., SchminckeVolatiles in submarine glasses as a discriminant of tectonic origin:application to the Troodos ophioliteNature, Vol. 343, No. 6254, January 11, pp. 159-161CyprusOphiolite, Tectonic origin
DS2000-0080
2000
Garcia, M.O.Bennett, V.C., Norman, M.D., Garcia, M.O.Rhenium and platinum group element abundances correlated with mantle source components.. picrites.Earth and Planetary Science Letters, Vol.183, No.3-4, pp.513-26.HawaiiMantle - chemistry, Picrites
DS2002-1153
2002
Garcia, M.O.Norman, M.D., Garcia, M.O., Kamenetsky, V.S., NielsenOlivine hosted melt inclusions in Hawaiian picrites: equilibration, melting and plume source characteristicsChemical Geology, Vol.183, 1-4, pp.143-68.HawaiiPicrites, Geochemistry
DS200612-0429
2006
Garcia, R.Garcia, R., Tkalcic, H., Chevrot, S.A new global PKP dat a set to study Earth's core and deep mantle.Physics of the Earth and Planetary Interiors, Vol. 159, 1-2, pp. 15-31.MantleGeophysics - seismics
DS1975-0513
1977
Garcia, V.Garcia, V., Aarden, H.M.Analysis Preliminar de Correlaciones Y Agrupaciones Geo-quimicas En Lateritas Del Cerro Impacto, Estado Bolivar.Fith. Congreso Geologico Venezolano, PP. 941-946.South America, VenezuelaLaterite, Geochemistry, Analyses
DS2003-0667
2003
Garcia, X.Jones, A.G., Lezaeta, P., Ferguson, I.J., Chave, A.D., Evans, R.L., Garcia, X.The electrical structure of the Slave CratonLithos, Vol. 71, 2-4, pp. 505-527.Northwest Territories, NunavutGeophysics - seismics
DS200412-0927
2003
Garcia, X.Jones, A.G., Lezaeta, P., Ferguson, I.J., Chave, A.D., Evans, R.L., Garcia, X., Spratt, J.The electrical structure of the Slave Craton.Lithos, Vol. 71, 2-4, pp. 505-527.Canada, NunavutGeophysics - seismics
DS200512-0316
2005
Garcia, X.Garcia, X., Jones, A.G.Electromagnetic image of the Trans Hudson Orogen - THO94 transect.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 479-483.Canada, Saskatchewan, ManitobaGeophysics - Lithoprobe
DS200612-0524
2006
Garcia, X.Hamilton, M.P., Jones, A.G., Evans, R.L., Evans, S., Fourie, C.J.S., Garcia, X., Mountford, A., Spratt, J.E., SAMTEX MTElectrical anisotropy of South African lithosphere compared with seismic anisotropy from shear wave splitting analyses.Physics of the Earth and Planetary Interiors, In press, availableAfrica, South AfricaGeophysics - magnetotellurics
DS201112-0312
2011
Garcia, X.Evans, R.L., Jones, A.G., Garcia, X., Muller, M., Hamilton, Evans, Fourie, Spratt, Webb, Jelsma, HutchinsElectrical lithosphere beneath the Kaapvaal craton, southern Africa.Journal of Geophysical Research, Vol. 116, B4, B04105.Africa, South AfricaGeophysics - seismics
DS201112-0672
2011
Garcia, X.Miensopust, M.P., Jones, A.G., Muller, M.R., Garcia, X., Evans, R.L.Lithospheric structures and Precambrian terrane boundaries in northeastern Botswana revealed through magnetotelluric profiling as part of southern AfricanJournal of Geophysical Research, Vol. 116, B02401Africa, BotswanaCraton, Zimbabwe
DS201112-0673
2011
Garcia, X.Miensopust, M.P., Jones, A.G., Muller, M.R., Garcia, X., Evans, R.L.Lithospheric structures and Precambrian terrane boundaries in northeastern Botswana revealed through magnetotelluric profiling as part of Southern Africa...Journal of Geophysical Research, Vol. 116, B02401 21p.Africa, BotswanaGeophysics - magnetotellurics
DS201612-2283
2016
Garcia-Casco, A.Cambeses, A., Garcia-Casco, A., Scarrow, J.H., Montero, P., Perez-Valera, L.A., Bea, F.Mineralogical evidence for lamproite magma mixing and storage at mantle depths: Socovos fault lamproites, SE Spain.Lithos, Vol. 266-267, pp. 182-201.Europe, SpainLamproite

Abstract: Detailed textural and mineral chemistry characterisation of lamproites from the Socovos fault zone, SE Spain Neogene Volcanic Province (NVP) combining X-ray element maps and LA-ICP-MS spot analyses has provided valuable information about mantle depth ultrapotassic magma mixing processes. Despite having similar whole-rock compositions, rocks emplaced in the Socovos fault are mineralogically varied: including type-A olivine-phlogopite lamproites; and type-B clinopyroxene-phlogopite lamproites. The Ol-lacking type-B predates Ol-bearing type-A by c. 2 million years. We propose that the mineralogical variations, which are representative of lamproites in the NVP as a whole, indicate mantle source heterogeneities. Major and trace element compositions of mineral phases suggest both metasomatised harzburgite and veined pyroxenite sources that were most likely closely spatially related. Thin section scale textural and compositional variations in mineral phases reveal heterogeneous mantle- and primitive magma-derived crystals. The variety of crystals points to interaction and mingling-mixing of ultrapotassic magma batches at mantle depths prior crustal emplacement. The mixing apparently occurred in a mantle melting zone with a channelised flow regime and localised magma chambers-reservoirs. Magma interaction was interrupted when the Socovos and other lithosphere-scale faults tore down to the mantle source region, triggering rapid ascent of the heterogeneous lamproite magma.
DS201711-2514
2017
Garcia-Casco, A.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.
DS201902-0270
2018
Garcia-Casco, A.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.
DS201909-2038
2019
Garcia-Casco, A.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
Garcia-Casco, A.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.
DS202106-0965
2021
Garcia-Casco, A.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.
DS201112-0481
2011
Garcia-Castellanos, D.Jemenez-Munt, I., Fernandez, M., Verges, J., Garcia-Castellanos, D., Fullea, J., Perez-Gussinye, M., Afonso, J.C.Decoupled crust mantle accommodation of Africa-Eurasia convergence in the NW Moroccan margin.Journal of Geophysical Research, Vol. 116, B08403, 12p.Africa, MoroccoGeophysics - density
DS201911-2526
2019
Garcia-Ruiz, J.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.
DS201112-0173
2011
Garcon, M.Chauvel, C., Garcon, M., Arndt, N.T., Gallet, S., Jahn, B.M.Average Nd hf isotopic compositions and model age of the upper continental crust.Goldschmidt Conference 2011, abstract p.646.Africa, South AfricaBeach placers
DS202003-0334
2019
Garcon, M.Carlson, R.W., Garcon, M., O'Neil, J., Reimink, J.,Rizo, H.The nature of the Earth's crust.Chemical Geology, Vol. 530, 25p. Available pdfMantleArchean geology

Abstract: Recycling of crust into the mantle has left only small remnants at Earth’s surface of crust produced within a billion years of Earth formation. Few, if any, of these ancient crustal rocks represent the first crust that existed on Earth. Understanding the nature of the source materials of these ancient rocks and the mechanism of their formation has been the target of decades of geological and geochemical study. This traditional approach has been expanded recently through the ability to simultaneously obtain U-Pb age and initial Hf isotope data for zircons from many of these ancient, generally polymetamorphic, rocks. The addition of information from the short-lived radiometric systems 146Sm-142Nd and 182Hf-182W allows resolution of some of the ambiguities that have clouded the conclusions derived from the long-lived systems. The most apparent of these is clear documentation that Earth experienced major chemical differentiation events within the first tens to hundreds of millions of years of its formation, and that Earth’s most ancient crustal rocks were derived from these differentiated sources, not from primitive undifferentiated mantle. Eoarchean rocks from the North Atlantic Craton and the Anshan Complex of the North China Craton have sources in an incompatible-element-depleted mantle that dates to 4.44.5 Ga. Hadean/Eoarchean rocks from two localities in Canada show the importance of remelting of Hadean mafic crust to produce Eoarchean felsic crust. The mafic supracrustal rocks of the Nuvvuagittuq Greenstone Belt are a possible example of the Hadean mafic basement that is often called upon to serve as the source for the high-silica rocks that define continental crust. Many, but not all, ancient terranes show a shift in the nature of the sources for crustal rocks, and possibly the physical mechanism of crust production, between 3.03.6 Ga. This transition may reflect the initiation of modern plate tectonics. Eoarchean/Hadean rocks from some terranes, however, also display compositional characteristics expected for convergent margin volcanism suggesting that at least some convergent margin related magmatism began in the Hadean. The persistence of isotopic variability in 142Nd/144Nd into the mid-Archean, and the eventual reduction in that variability by the end of the Archean, provides new information on the efficiency by which mantle convection recombined the products of Hadean silicate-Earth differentiation. The rate of crust production and recycling in the Hadean/Archean, however, is not resolved by these data beyond the observation that extreme isotopic compositions, such as expected for Hadean evolved, continent-like, crust are not observed in the preserved Eoarchean rock record. The lack of correlation between 142Nd/144Nd and 182W/184W variation in Archean rocks suggests that these two systems track different processes; the Sm-Nd system mantle-crust differentiation while Hf-W is dominated by core formation. The major silicate differentiation controlling Sm/Nd fractionation occurred at ?4.4 Ga, possibly as a result of the Moon-forming impact, after the extinction of 182Hf.
DS202201-0043
2022
Gard, M.Tamblyn, R., Hasterok, D., Hand, M. , Gard, M.Mantle heating at ca. 2 Ga by continental insulation: evidence from granites and eclogites ** not specific to diamonds.Geology, Vol. 50, 1 pp. 91-95.Mantlethermometry
DS202202-0218
2022
Gard, M.Tamblyn, R., Hasterok, D., Hand, M., Gard, M.Mantle heating at ca 2 Ga by continental insulation: evidence from granites and eclogites.Geology, Vol. 50, 1, pp. 91-96.Mantleeclogites

Abstract: Igneous and metamorphic rocks contain the mineralogical and geochemical record of thermally driven processes on Earth. The generally accepted thermal budget of the mantle indicates a steady cooling trend since the Archean. The geological record, however, indicates this simple cooling model may not hold true. Subduction-related eclogites substantially emerge in the rock record from 2.1 Ga to 1.8 Ga, indicating that average mantle thermal conditions cooled below a critical threshold for widespread eclogite preservation. Following this period, eclogite disappeared again until ca. 1.1 Ga. Coincident with the transient emergence of eclogite, global granite chemistry recorded a decrease in Sr and Eu and increases in yttrium and heavy rare earth element (HREE) concentrations. These changes are most simply explained by warming of the thermal regime associated with granite genesis. We suggest that warming was caused by increased continental insulation of the mantle at this time. Ultimately, secular cooling of the mantle overcame insulation, allowing the second emergence and preservation of eclogite from ca. 1.1 Ga until present.
DS1994-0575
1994
Garda, G.Garda, G., Eggins, S.Trace element characteristics of the lamprophyric dykes from the north coast of Sao Paulo State, Brasil.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 106-107.BrazilDike, Geochemistry
DS1994-0576
1994
Garda, G.Garda, G., Esperanca, S., Carlson, R.W.The petrology and geochemistry of coastal dikes Sao Paulo State:implications lithospheric alkaline magmas.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 62-64.BrazilGeochemistry, Alkaline rocks
DS1990-1395
1990
Garda, G.M.Sonoki, I.K., Garda, G.M.K-Ar ages of alkaline rock from Southern Brasil and Eastern Paraguay:compilation and adaptation of new decay constants. (in Portugese).National Technical Information Service Rept, No. DE90635110/WNR 17p. United States Sales $ 15.00 AO3Brazil, ParaguayAlkaline rocks, Geochronology
DS2000-1006
2000
GardeWardle, R.J., Scott, D.m Van Gool, GardeAn overview of development of northeast Laurentia: Nain - Superior collision and links to Trans Hudson OrogenGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000, 4p. abstract.Northwest Territories, Ontario, Quebec, UngavaTectonics - orogens, Laurentia
DS2002-0501
2002
Garde, A.A.Garde, A.A., Hamilton, M.A., Chadwick, B., Grocott, J., McCaffrey, K.J.W.The Ketilidian orogen of South Greenland: geochronology, tectonics, magmatism andCanadian Journal of Earth Science, Vol.39,5, May, pp.765-93.GreenlandTectonics
DS200612-0270
2006
Garde, A.A.Connelly, J.N., Thrane, K., Krawiec, A.W., Garde, A.A.Linking the Paleoproterozoic Nagssugtoqidian and Rinkian orogens through Disko Bugt region of West Greenland.Journal of the Geological Society, Vol. 163, 2, pp. 319-335.Europe, GreenlandOrogen - not specific to diamonds
DS200912-0727
2009
Garde, A.A.St.Onge, M.R., Van Gool, A.M., Garde, A.A., Scott, D.J.Correlation of Archean and paleoproterozoic units between northeastern Canada and western Greenland: constraining the pre-collisional upper plate accretionary historyGeological Society of London, Special Publication Earth Accretionary systems in Space and Time, No. 318, pp. 193-235.Canada, Ontario, Europe, GreenlandTrans-Hudson Orogen
DS200912-0816
2009
Garde, A.A.Windley, B.F., Garde, A.A.Arc generated blocks with crustal sections in the North Atlantic Craton of West Greenland: crustal growth in the Archean with modern analogues.Earth Science Reviews, Vol. 93, 1-2, pp. 1-30.Europe, GreenlandTectonics
DS1993-0379
1993
Garde, m A.A.Dueholm, K.S., Garde, m A.A., Pedersen, A.K.Preparation of accurate geological and structural maps, cross sections orb lock diagrams from colour slides, using multi-model photogrammetryJournal of Structural Geology, Vol. 15, No. 7, pp. 933-937GlobalStructure, Maps, slides
DS2003-0440
2003
Garden, B.P.Garden , B.P., Carlson, R.W., Shirey, S.B., Gurney, J.J.RE OS systematics of lithospheric peridotites and eclogites from the Bobbejan and8ikc, Www.venuewest.com/8ikc/program.htm, Session 4, POSTER abstractSouth AfricaMantle geochemistry, Deposit - Bobbejan, Bellsbank, Jagersfontein
DS201510-1786
2015
Gardes, E.Massuyeau, M., Gardes, E., Morizet, Y., Gaillard, F.A model for the activity of silica along the carbonatite-kimberlite-mellilitite-basanite melt compositional joint.Chemical Geology, Vol. 418, pp. 206-216.TechnologyKimberlite

Abstract: Carbon dioxide and water, being present in the Earth's mantle at concentration levels of tens to hundreds of ppm, greatly lower the peridotite solidus temperature and drastically modify the composition of produced melts. The presence of CO2 produces silica-poor, carbonate-rich liquids at the onset of melting, and these liquids shift toward silica rich compositions as the degree of melting increases. Numerous geochemical observations and experimental studies have revealed the complexity of the transition between carbonate-rich and silicate-rich melts. It is characterized by a strongly non-linear evolution and, under specific conditions, by immiscibility. To better constrain this transition, we have used the thermodynamic activity of silica as a probe of the mixing properties between molten carbonate and molten silicate. The activity of silica (aSiO2(l))aSiO2l was calculated for a large number of experimental liquids from two equilibria: olivine-orthopyroxene-melt and immiscible silicate-rich melt-carbonate-rich melt (491 data points ranging from 1 to 14 GPa and 1090 to 1800 °C). We modelled aSiO2(l)aSiO2l during incipient melting of the peridotite in presence of CO2 with a generalized Margules function. Our model reproduces well the silica activity-composition relationships of the experimental database, and can be used to predict the silica content of the melts coexisting with olivine and orthopyroxene. We show that water content and Ca/Mg ratio in the melts have an important influence on the aSiO2(l)aSiO2l. In contrast to a recent empirical model (Dasgupta et al., 2013), the analysis of the experimental database reveals that the transition from carbonate to silicate melt with decreasing depth should occur abruptly in oceanic mantle. Our model predicts that carbonatitic melts with ~ 5 wt.% SiO2 can be stabilized from ~ 150 km depth, at the onset of incipient melting by "redox melting", up to ~ 75 km, above which the liquid evolves abruptly to a carbonated silicate composition (> ~ 25 wt.% SiO2). In the cratonic mantle lithosphere, our model predicts that carbonatitic melts are prevailing up to shallow depth, and conflicts the recent model (Russell et al., 2012) of CO2-saturation triggered by orthopyroxene assimilation during kimberlite ascent.
DS202102-0207
2021
Gardes, E.Massuyeau, M., Gardes, E., Rogerie, G., Aulbach, S., Tappe, S., Le Trong, E., Sifre, D., Gaillard, F.MAGLAB: A computing platform connecting geophysical signatures to melting processes in Earth's mantle.Physics of the Earth and Planetary Interiors, doi.org/10.1016/ j.pepi.2020.106638 51p. PdfMantlegeophysics - magnetics

Abstract: Decompression melting of the upper mantle produces magmas and volcanism at the Earth's surface. Experimental petrology demonstrates that the presence of CO2 and H2O enhances peridotite melting anywhere within the upper mantle down to approximately 200-300?km depth. The presence of mantle melts with compositions ranging from carbonate-rich to silicate-rich unavoidably affects the geophysical signals retrieved from Earth's mantle. Geochemical investigations of erupted intraplate magmas along with geophysical surveys allow for constraining the nature and volume of primary melts, and a sound formalism is required to integrate these diverse datasets into a realistic model for the upper mantle including melting processes. Here, we introduce MAGLAB, a model developed to calculate the composition and volume fraction of melts in the upper mantle, together with the corresponding electrical conductivity of partially molten mantle peridotites at realistic pressure-temperature conditions and volatile contents. We use MAGLAB to show how the compositions of intraplate magmas relate to variations in lithosphere thickness. Progressive partial melting of a homogeneous peridotitic mantle source can in theory create the diversity of compositions observed among the spectrum of intraplate magma types, with kimberlite melts beneath thick continental shields, alkaline magmas such as melilitite, nephelinite and basanite beneath thinner continents and relatively old plus thick oceanic lithospheres, and ‘regular’ basalts beneath the youngest and thinnest oceanic lithospheres as well as beneath significantly thinned continental lithospheres. MAGLAB calculations support recent experimental findings about the role of H2O in the upper mantle on producing primary kimberlitic melts in addition to CO2. We demonstrate the robustness of MAGLAB calculations by reproducing the compositions of erupted melts as well as associated mantle electrical conductivities beneath the Society hotspot in the Pacific Ocean. A comparison of our simulations with magnetotelluric surveys at various oceanic settings shows that the heterogeneities in electrical conductivity of Earth's upper mantle are related to variations in volatile content via the presence of small (generally <<1?wt%) and heterogeneously distributed fractions of CO2-H2O-bearing melts.
DS202112-1927
2021
Gardes, E.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.
DS201312-0090
2013
Gardien, V.Boulvais, P., Decree, S., Cobert, C., Midende, G., Tack, L., Gardien, V., Demaiffe, D.C and O isotope compositios of the Matongo carbonatite ( Burundi): new insights into alteration and REE mineralization processes.Goldschmidt 2013, AbstractAfrica, BurundiCarbonatite
DS1992-0598
1992
Gardiner, C.F.Graebner, J.E., Jin, S., Kammlott, G.W., Herb, J.A., Gardiner, C.F.Large anisotropic thermal conductivity in synthetic diamond filmsNature, Vol. 359, No. 6394, October 1, pp. 401-402GlobalDiamond synthesis, CVD.
DS201903-0522
2019
Gardiner, C.L.Johnson, T.E., Kirkland, C.L., Gardiner, C.L., Gardiner, N.J., Brown, M., Smithies, R.H., Santosh, M.Secular change in TTG compositions: implications for the evolution of Archean geodynamics.Earth and Planetary Science Letters, Vol. 505, pp. 65-75.Mantlegeothermometry

Abstract: It is estimated that around three quarters of Earth's first generation continental crust had been produced by the end of the Archaean Eon, 2.5 billion years ago. This ancient continental crust is mostly composed of variably deformed and metamorphosed magmatic rocks of the tonalite-trondhjemite-granodiorite (TTG) suite that formed by partial melting of hydrated mafic rocks. However, the geodynamic regime under which TTG magmas formed is a matter of ongoing debate. Using a filtered global geochemical dataset of 563 samples with ages ranging from the Eoarchaean to Neoarchaean (4.0-2.5 Ga), we interrogate the bulk rock major oxide and trace element composition of TTGs to assess evidence for secular change. Despite a high degree of scatter in the data, the concentrations or ratios of several key major oxides and trace elements show statistically significant trends that indicate maxima, minima and/or transitions in the interval 3.3-3.0 Ga. Importantly, a change point analysis of K2O/Na2O, Sr/Y and LaN/YbN demonstrates a statistically significant (>99% confidence) change during this 300 Ma period. These shifts may be linked to a fundamental change in geodynamic regime around the peak in upper mantle temperatures from one dominated by non-uniformitarian, deformable stagnant lid processes to another dominated by the emergence of global mobile lid or plate tectonic processes by the end of the Archaean. A notable change is also evident at 2.8-2.7 Ga that coincides with a major jump in the rate of survival of metamorphic rocks with contrasting thermal gradients, which may relate to the emergence of more potassic continental arc magmas and an increased preservation potential during collisional orogenesis. In many cases, the chemical composition of TTGs shows an increasing spread through the Archaean, reflecting the irreversible differentiation of the lithosphere.
DS1910-0050
1910
Gardiner, C.R.Gardiner, C.R.Native Gems of North AmericaJewellers Circular Keystone, Vol. 61, No. 21, Dec. 21ST. PP. 75-77. ALSO: Vol. 61, No. 22United States, Gulf Coast, Arkansas, North Carolina, Appalachia, CaliforniaNews Item
DS1910-0282
1912
Gardiner, C.R.Gardiner, C.R.History of the Diamond Fields of South AfricaSouth African Mining Journal, Vol. 9, PT. 2, MARCH PP. 41-43.South AfricaHistory
DS1900-0555
1907
Gardiner, G.R.Gardiner, G.R.The Diamond (1907)Miner. Coll., Vol. 14, NOVEMBER, PP. 129-133.Africa, South AfricaMining Engineering
DS201704-0630
2017
Gardiner, N.J.Johnson, T.E., Brown, M., Gardiner, N.J., Kirkland, C.L., Smithies, R.H.Earth's first stable continents did not form by subduction.Nature, Vol. 543, pp. 239-242.MantleGeodynamics

Abstract: The geodynamic environment in which Earth’s first continents formed and were stabilized remains controversial1. Most exposed continental crust that can be dated back to the Archaean eon (4 billion to 2.5 billion years ago) comprises tonalite-trondhjemite-granodiorite rocks (TTGs) that were formed through partial melting of hydrated low-magnesium basaltic rocks2; notably, these TTGs have ‘arc-like’ signatures of trace elements and thus resemble the continental crust produced in modern subduction settings3. In the East Pilbara Terrane, Western Australia, low-magnesium basalts of the Coucal Formation at the base of the Pilbara Supergroup have trace-element compositions that are consistent with these being source rocks for TTGs. These basalts may be the remnants of a thick (more than 35?kilometres thick), ancient (more than 3.5 billion years old) basaltic crust4, 5 that is predicted to have existed if Archaean mantle temperatures were much hotter than today’s6, 7, 8. Here, using phase equilibria modelling of the Coucal basalts, we confirm their suitability as TTG ‘parents’, and suggest that TTGs were produced by around 20 per cent to 30 per cent melting of the Coucal basalts along high geothermal gradients (of more than 700 degrees Celsius per gigapascal). We also analyse the trace-element composition of the Coucal basalts, and propose that these rocks were themselves derived from an earlier generation of high-magnesium basaltic rocks, suggesting that the arc-like signature in Archaean TTGs was inherited from an ancestral source lineage. This protracted, multistage process for the production and stabilization of the first continents—coupled with the high geothermal gradients—is incompatible with modern-style plate tectonics, and favours instead the formation of TTGs near the base of thick, plateau-like basaltic crust9. Thus subduction was not required to produce TTGs in the early Archaean eon.
DS201809-2046
2018
Gardiner, N.J.Johnson, T.E., Gardiner, N.J., Miljkovic, K., Spencer, C.J., Kirkland, C.L., Bland, P.A., Smithies, R.H.Are Earth's oldest felsic rocks impact melts? Acasta Gneiss ComplexGoldschmidt Conference, 1p. AbstractCanada, Northwest Territoriesmeteorite

Abstract: Earth’s oldest felsic rocks, the 4.02 billion-year-old Idiwhaa gneisses of the Acasta Gneiss Complex, northwest Canada, have compositions that are distinct from the felsic rocks that typify Earth’s ancient continental nuclei, implying they formed through a different process. Using phase equilibria and trace element modelling, we show that the Idiwhaa gneisses were produced by partial melting of ironrich amphibolite host rocks at very low pressures, equating to the uppermost ~3 km of mafic crust. The heat required for such shallow melting is most easily explained through meteorite impacts. Hydrodynamic impact modelling shows that, not only is this scenario physically plausible, but the region of shallow melting appropriate to formation of the Idiwhaa gneisses would have been widespread. Given the predicted high flux of meteorites during the late Hadean, impact melting may have been the predominant mechanism that generated Hadean felsic rocks.
DS201810-2318
2018
Gardiner, N.J.Gardiner, N.J., Searle, M.P., Morley, C.K., Robb, L.J., Whitehouse, M.J., Roberts, N.M.W., Kirkland, C.L., Spencer, C.J.The crustal architecture of Myanmar imaged through zircon U-Pb, Lu-Hf and O isotopes: tectonic and metallogenic implications. ReviewGondwana Research, Vol. 62, pp. 27-60.Asia, Myanmartectonics

Abstract: The Tethys margin in central and eastern Asia is comprised of continental terranes separated by suture zones, some of which remain cryptic. Determining the crustal architecture, and therefore the geological history, of the Eastern Tethyan margin remains challenging. Sited in the heart of this region, Myanmar is a highly prospective but poorly explored minerals jurisdiction. A better understanding of Myanmar's mineralization can only be realized through a better understanding of its tectonic history, itself reflected in at least four major magmatic belts. The Eastern and the Main Range Provinces are associated with the Late Permian to Early Triassic closure of Palaeo-Tethys. The Mogok-Mandalay-Mergui Belt and Wuntho-Popa Arc are a response to the Eocene closure of Neo-Tethys. However, magmatic ages outside these two orogenic events are also recorded. We present new zircon U-Pb, Lu-Hf and O isotope data from magmatic rocks across Myanmar, which we append to the existing dataset to isotopically characterize Myanmar's magmatic belts. Eastern Province Permian I-type magmatism has evolved eHf (-10.9 to -6.4), whilst Main Range Province Triassic S-type magmatism also records evolved eHf (-13.5 to -8.8). The Mogok-Mandalay-Mergui Belt is here divided into the Tin Province and the Mogok Metamorphic Belt. The Tin Province hosts ca. 77-50 Ma magmatism with evolved eHf (-1.2 to -15.2), and d 18 O of 5.6-8.3‰. The Mogok Metamorphic Belt exhibits a more complex magmatic and metamorphic history, and granitoids record Jurassic, Late Cretaceous, and Eocene to Miocene phases of magmatism, all of which exhibit evolved eHf values between -4.6 and -17.6, and d 18 O between 6.3 and 9.2‰. From the Tagaung-Myitkyina Belt, we report a magmatic age of 172 Ma and eHf of 18.1 to 10.8. To accommodate the geological evidence, we propose a tectonic model for Myanmar involving a greater Sibumasu - where the documented zircon isotopic variations reflect compositional variations in magmatic source - and invoke the role of a Tengchong Block. The Baoshan Block and Greater Sibumasu were likely assembled on or before the Triassic, a former Andean margin and suture which may lie across the Northern Shan Plateau, and reflected in isotopic differences between the northern and southern parts of the Mogok Metamorphic Belt. This contiguous Sibumasu-Baoshan Block then sutured onto the Indochina margin in the Late Triassic. We propose that a Tengchong Block within Myanmar provides for a southerly termination of the Meso-Tethys suture immediately north of the Mogok area. A discrete Tengchong Block may explain a discontinuous arc of Late Triassic to Jurassic I-type magmatism in central Myanmar, representing an Andean-type margin sited above a subducting Meso-Tethys on the margin of Sibumasu. The Tengchong Block sutured onto Greater Sibumasu before the Late Cretaceous, after which subduction of Neo-Tethys drove the magmatism of the Wuntho-Popa Arc and ultimately that of the Tin Province. The metallogenic character of granite belts in Myanmar reflects the crustal architecture of the region, which is remarkable for its prolific endowment of granite-hosted Sn-W mineralization in two quite distinct granite belts related to sequential Indosinian and Himalayan orogenesis.
DS201811-2582
2018
Gardiner, N.J.Johnson, T.E., Gardiner, N.J., Miljkovic, K., Spencer, C.J., Kirkland, C.L., Bland, P.A., Smithies, H.An impact melt origin for Earth's oldest known evolved rocks. Acasta GneissNature Geoscience, Vol. 11, pp. 795-799.Canada, Northwest Territoriesmelting

Abstract: Earth’s oldest evolved (felsic) rocks, the 4.02-billion-year-old Idiwhaa gneisses of the Acasta Gneiss Complex, northwest Canada, have compositions that are distinct from the felsic rocks that typify Earth’s ancient continental nuclei, implying that they formed through a different process. Using phase equilibria and trace element modelling, we show that the Idiwhaa gneisses were produced by partial melting of iron-rich hydrated basaltic rocks (amphibolites) at very low pressures, equating to the uppermost ~3?km of a Hadean crust that was dominantly mafic in composition. The heat required for partial melting at such shallow levels is most easily explained through meteorite impacts. Hydrodynamic impact modelling shows not only that this scenario is physically plausible, but also that the region of shallow partial melting appropriate to formation of the Idiwhaa gneisses would have been widespread. Given the predicted high flux of meteorites in the late Hadean, impact melting may have been the predominant mechanism that generated Hadean felsic rocks.
DS201903-0522
2019
Gardiner, N.J.Johnson, T.E., Kirkland, C.L., Gardiner, C.L., Gardiner, N.J., Brown, M., Smithies, R.H., Santosh, M.Secular change in TTG compositions: implications for the evolution of Archean geodynamics.Earth and Planetary Science Letters, Vol. 505, pp. 65-75.Mantlegeothermometry

Abstract: It is estimated that around three quarters of Earth's first generation continental crust had been produced by the end of the Archaean Eon, 2.5 billion years ago. This ancient continental crust is mostly composed of variably deformed and metamorphosed magmatic rocks of the tonalite-trondhjemite-granodiorite (TTG) suite that formed by partial melting of hydrated mafic rocks. However, the geodynamic regime under which TTG magmas formed is a matter of ongoing debate. Using a filtered global geochemical dataset of 563 samples with ages ranging from the Eoarchaean to Neoarchaean (4.0-2.5 Ga), we interrogate the bulk rock major oxide and trace element composition of TTGs to assess evidence for secular change. Despite a high degree of scatter in the data, the concentrations or ratios of several key major oxides and trace elements show statistically significant trends that indicate maxima, minima and/or transitions in the interval 3.3-3.0 Ga. Importantly, a change point analysis of K2O/Na2O, Sr/Y and LaN/YbN demonstrates a statistically significant (>99% confidence) change during this 300 Ma period. These shifts may be linked to a fundamental change in geodynamic regime around the peak in upper mantle temperatures from one dominated by non-uniformitarian, deformable stagnant lid processes to another dominated by the emergence of global mobile lid or plate tectonic processes by the end of the Archaean. A notable change is also evident at 2.8-2.7 Ga that coincides with a major jump in the rate of survival of metamorphic rocks with contrasting thermal gradients, which may relate to the emergence of more potassic continental arc magmas and an increased preservation potential during collisional orogenesis. In many cases, the chemical composition of TTGs shows an increasing spread through the Archaean, reflecting the irreversible differentiation of the lithosphere.
DS202002-0187
2020
Gardiner, N.J.Gardiner, N.J., Kirkland, C.L., Hollis, J.A., Cawood, P.A., Nebel, O., Szilas, K., Yakymchuk, C.North Atlantic craton architecture revealed by kimberlite-hosted crustal zircons.Earth and Planetary Science Letters, Vol. 534, 8p. PdfEurope, Greenlandkimberlite genesis

Abstract: Archean cratons are composites of terranes formed at different times, juxtaposed during craton assembly. Cratons are underpinned by a deep lithospheric root, and models for the development of this cratonic lithosphere include both vertical and horizontal accretion. How different Archean terranes at the surface are reflected vertically within the lithosphere, which might inform on modes of formation, is poorly constrained. Kimberlites, which originate from significant depths within the upper mantle, sample cratonic interiors. The North Atlantic Craton, West Greenland, comprises Eoarchean and Mesoarchean gneiss terranes - the latter including the Akia Terrane - assembled during the late Archean. We report U-Pb and Hf isotopic, and trace element, data measured in zircon xenocrysts from a Neoproterozoic (557 Ma) kimberlite which intruded the Mesoarchean Akia Terrane. The zircon trace element profiles suggest they crystallized from evolved magmas, and their Eo-to Neoarchean U-Pb ages match the surrounding gneiss terranes, and highlight that magmatism was episodic. Zircon Hf isotope values lie within two crustal evolution trends: a Mesoarchean trend and an Eoarchean trend. The Eoarchean trend is anchored on 3.8 Ga orthogneiss, and includes 3.6-3.5 Ga, 2.7 and 2.5-2.4 Ga aged zircons. The Mesoarchean Akia Terrane may have been built upon mafic crust, in which case all zircons whose Hf isotopes lie within the Eoarchean trend were derived from the surrounding Eoarchean gneiss terranes, emplaced under the Akia Terrane after ca. 2.97 or 2.7 Ga, perhaps during late Archean terrane assembly. Kimberlite-hosted peridotite rhenium depletion model ages suggest a late Archean stabilization for the lithospheric mantle. The zircon data support a model of lithospheric growth via tectonic stacking for the North Atlantic Craton.
DS202005-0723
2020
Gardiner, N.J.Brown, M., Johnson, T., Gardiner, N.J.Plate tectonics and the Archean Earth.Annual Review of Earth and Planetary Sciences, Vol. 48, 30p. pdfMantlesubduction, metamorphism

Abstract: If we accept that a critical condition for plate tectonics is the creation and maintenance of a global network of narrow boundaries separating multiple plates, then to argue for plate tectonics during the Archean requires more than a local record of subduction. A case is made for plate tectonics back to the early Paleoproterozoic, when a cycle of breakup and collision led to formation of the supercontinent Columbia, and bimodal metamorphism is registered globally. Before this, less preserved crust and survivorship bias become greater concerns, and the geological record may yield only a lower limit on the emergence of plate tectonics. Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. This transition is recorded by changes in geochemical proxies and interpreted based on numerical modeling. Improved understanding of the secular evolution of temperature and water in the mantle are key targets for future research. 1) Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. 2) Plate tectonics can be demonstrated on Earth since the early Paleoproterozoic (since c. 2.2 Ga), but before the Proterozoic Earth's tectonic mode remains ambiguous. 3) The Mesoarchean to early Paleoproterozoic (3.2-2.3 Ga) represents a period of transition from an early tectonic mode (stagnant or sluggish lid) to plate tectonics. 4) The development of a global network of narrow boundaries separating multiple plates could have been kick-started by plume-induced subduction.
DS202007-1126
2020
Gardiner, N.J.Brown, M., Johnson, T., Gardiner, N.J.Plate tectonics and the Archean Earth.Annual Review of Earth and Planetary Sciences, Vol. 48, 1, pp. 291-320.Mantletectonics

Abstract: If we accept that a critical condition for plate tectonics is the creation and maintenance of a global network of narrow boundaries separating multiple plates, then to argue for plate tectonics during the Archean requires more than a local record of subduction. A case is made for plate tectonics back to the early Paleoproterozoic, when a cycle of breakup and collision led to formation of the supercontinent Columbia, and bimodal metamorphism is registered globally. Before this, less preserved crust and survivorship bias become greater concerns, and the geological record may yield only a lower limit on the emergence of plate tectonics. Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. This transition is recorded by changes in geochemical proxies and interpreted based on numerical modeling. Improved understanding of the secular evolution of temperature and water in the mantle is a key target for future research.
DS202111-1777
2021
Gardiner, N.J.Mulder, J.A., Nevel, O., Gardiner, N.J., Cawood, P.A., Wainwright, A.N., Ivanic, T.J.Crustal rejuvenation stabilised Earth's first cratons.Nature Communications, Vol. 12, 3535, 8p. pdfMantlecraton

Abstract: The formation of stable, evolved (silica-rich) crust was essential in constructing Earth’s first cratons, the ancient nuclei of continents. Eoarchaean (4000-3600 million years ago, Ma) evolved crust occurs on most continents, yet evidence for older, Hadean evolved crust is mostly limited to rare Hadean zircons recycled into younger rocks. Resolving why the preserved volume of evolved crust increased in the Eoarchaean is key to understanding how the first cratons stabilised. Here we report new zircon uranium-lead and hafnium isotope data from the Yilgarn Craton, Australia, which provides an extensive record of Hadean-Eoarchaean evolved magmatism. These data reveal that the first stable, evolved rocks in the Yilgarn Craton formed during an influx of juvenile (recently extracted from the mantle) magmatic source material into the craton. The concurrent shift to juvenile sources and onset of crustal preservation links craton stabilisation to the accumulation of enduring rafts of buoyant, melt-depleted mantle.
DS202102-0237
2021
Gardinerm N.J.Yakmchuck, C., Kirkland, C.L., Cavosie, A.J., Szilas, K., Hollis, J., Gardinerm N.J., Waterton, P., Steenfelt, A., Martin, L.Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland.Earth and Planetary Science Letters, Vol. 557, doi.org/10.1016/ j.epsl.2020.116730 9p. PdfEurope, Greenlandmeteorite

Abstract: Large meteorite impacts have a profound effect on the Earth's geosphere, atmosphere, hydrosphere and biosphere. It is widely accepted that the early Earth was subject to intense bombardment from 4.5 to 3.8 Ga, yet evidence for subsequent bolide impacts during the Archean Eon (4.0 to 2.5 Ga) is sparse. However, understanding the timing and magnitude of these early events is important, as they may have triggered significant change points to global geochemical cycles. The Maniitsoq region of southern West Greenland has been proposed to record a ?3.0 Ga meteorite impact, which, if confirmed, would be the oldest and only known impact structure to have survived from the Archean. Such an ancient structure would provide the first insight into the style, setting, and possible environmental effects of impact bombardment continuing into the late Archean. Here, using field mapping, geochronology, isotope geochemistry, and electron backscatter diffraction mapping of 5,587 zircon grains from the Maniitsoq region (rock and fluvial sediment samples), we test the hypothesis that the Maniitsoq structure represents Earth's earliest known impact structure. Our comprehensive survey shows that previously proposed impact-related geological features, ranging from microscopic structures at the mineral scale to macroscopic structures at the terrane scale, as well as the age and geochemistry of the rocks in the Maniitsoq region, can be explained through endogenic (non-impact) processes. Despite the higher impact flux, intact craters from the Archean Eon remain elusive on Earth.
DS201312-0296
2013
Gardner, C.Gardner, C.Ethical considerations for the trade and trade associations.Diamond Intelligence Briefs, No. 745, Feb. 6, 2p.GlobalKP, CSR
DS1859-0084
1846
Gardner, G.Gardner, G.Travels in the Interior of Brasil, Principally through the Northern Provinces and the Gold and Diamond Districts During the Years 1836-1841.London: Reeve Bros., 575P. ( DIAMOND FIELDS PP. 442-471 )South America, BrazilTravelogue
DS200412-0343
2004
Gardner, P.Coish, R.A., Gardner, P.Supra subduction zone peridotite in the northern USA Appalachians: evidence from mineral composition.Mineralogical Magazine, Vol. 68, 4, Aug. 1, pp. 699-708.United States, AppalachiaSubduction
DS200512-0176
2004
Gardner, P.Coish, R.A., Gardner, P.Supra subduction zone peridotite in the northern USA Appalachians: evidence from mineral composition.Mineralogical Magazine, Vol. 68, 4, Aug. 1, pp. 699-708.United States, AppalachiaSubduction
DS1989-0473
1989
Gardner, T.W.Gardner, T.W., Sevon, W.D.Appalachian geomorphologyElsevier Publ, ISBN 0-444-88326-6 318p. Approx. $ 100.00 United StatesGlobalPiedmont, Geomorphology
DS1997-1061
1997
Gardoll, S.J.Smith, A.B., Gardoll, S.J.Structural analysis in mineral exploration using a Geographic InformationSystems- adapted stereographic.Australian Journal of Earth Sciences, Vol. 44, pp. 445-452AustraliaComputer - GIS
DS1996-0480
1996
Gardu, G.Gardu, G.Geophysical and mineralogical dat a about diamond paragenetic minerals in Moldavian plate, Romania.Geological Society of America (GSA) Abstracts, Vol. 28, No. 7, p. A-414.RomaniaGeophysics, Moissanite
DS2000-0311
2000
Gardu, G.Gardu, G.Potential Diamondiferous structures in south western part of East European plate ( EEP) Romania.Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-429.RomaniaTectonics, Moldavian plate, Subduction
DS200512-0317
2004
Gardu, G.G.Gardu, G.G.Potential Diamondiferous structures in southwestern part of East European Plate (EEP) Romania.Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 213-4, Vol. 36, 5, p. 495.Europe, RomaniaMoldavian Plate, subduction
DS2001-1001
2001
Gareau, T.Sage, R.P., Gareau, T.A compilation of references for kimberlite, diamond and related topicsOntario Geological Survey Open file, No. 6067, 117p. MR Data 86, $50.OntarioBibliography
DS202005-0754
2020
Gareev, B.I.Nosova, A.A., Kargin, A.V., Sazonova, L.V., Dubinina, E.O., Chugaev, A.V., Lebedeva, N.M., Yudin, D.S., Larionova, Y.O., Abersteiner, A., Gareev, B.I., Batalin, G.A.Sr-Nd-Pb isotopic systematic and geochronology of ultramafic alkaline magmatism of the southwestern margin of the Siberian craton: metasomatism of the sub-continental lithospheric mantle related to subduction and plume events.Lithos, Vol. 364-365, 21p. PdfRussia, Siberiadeposit - Ilbokich, Chadobets

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

Abstract: To provide new insights into the origin and evolution of ultramafic lamprophyres (UMLs) and their mantle source, we examined two UML (aillikite and damtjernite) occurrences of different ages in the western portion of the Siberian Craton (Ilbokich and Chadobets). New age, mineral and rock geochemistry, along with Sr-Nd-Pb-C-O isotope data was obtained. Our new 206Pb/238U perovskite age (399 ± 4 Ma) confirms the previously published Early Devonian age of the Ilbokich aillikite. RbSr isochron and 40Ar/39Ar dating yielded a Middle Triassic age (243 ± 3 Ma and 241 ± 1 Ma, respectively) for the Chadobets aillikites, indicating post-Trap emplacement of these rocks. Both UMLs are characterized by incompatible elements, including light rare earth element (LREE) enrichments (La is up to ×200 chondrite concentration), and strong fractionation of REEs ((La/Yb)n: 33-84). Despite the close geochemical affinity of both UMLs, the Nd isotopic compositions of aillikites, as well as the Pb isotopic composition of Chadobets and Ilbokich UMLs, do not overlap and are distinctly different from each other. The initial Sr and Nd isotopic compositions of the Ilbokich UMLs fall in within a narrow 87Sr/86Sr0 range (0.7032-0.7042) and ?Nd(T) (4.03-3.97). Chadobets UMLs have a similar Sr isotopic signature (87Sr/86Sr0: 0.7031-0.7043) and a more depleted Nd isotopic signature (?Nd(T) 4.09-5.08). The initial Pb isotope compositions of the Chadobets UMLs are moderately radiogenic, ranging between 206Pb/204Pb = 18.4-19.0, 208Pb/204Pb = 38.3-38.8, and are characterized by a narrow 207Pb/204Pb ratio between 15.5 and 15.6. The Ilbokich Pb isotope compositions are less variable and range between 206Pb/204Pb = 18.0-18.4, 208Pb/204Pb = 37.8-38.4 and 207Pb/204Pb ratios between 15.5 and 15.6. The oxygen isotopic composition of carbonate from both UMLs is characterized by highly variable ?18O values from +12.1 and up to +20.5‰ (SMOW). The isotopic composition of ?13C values range from ?1.3‰ to ?7.1. Based on the minor impact of crustal contamination in both aillikites, it is inferred that their radiogenic isotope composition reflects a mantle source signature. The mantle source of the Chadobets aillikites is likely to include carbonatitic magma as a metasomatic agent. In contrast, phlogopite-rich metasomes within the lithospheric mantle could have contributed more significantly to the Ilbokich aillikites. These metasomes could be formed during the Caledonian orogeny, which did not only affect the southwestern boundary of the Siberian Craton, but also expanded to the craton interior. This study provides additional support for the evolution of the south-western portion of the Siberian SCLM, ranging from mantle containing phlogopite enrichment domains during the Early Devonian to hydrous-phase reduced mantle in the Triassic due to the thermal impact of the Siberian Traps.
DS1930-0160
1934
Gareger, H.S.Gareger, H.S.Discussion of Paper by Shand "the Heavy Minerals of Kimberlites".Geological Society of South Africa Proceedings, Vol. 37, PP. 64-67.South AfricaHeavy Minerals Concentrations
DS201707-1329
2017
Garel, F.Goes, S., Agrusta, R., van Hunen, J., Garel, F.Subduction - transition zone interaction: a review.Geosphere, Vol. 13, 3, pp. 644-8.Mantlesubduction

Abstract: As subducting plates reach the base of the upper mantle, some appear to flatten and stagnate, while others seemingly go through unimpeded. This variable resistance to slab sinking has been proposed to affect long-term thermal and chemical mantle circulation. A review of observational constraints and dynamic models highlights that neither the increase in viscosity between upper and lower mantle (likely by a factor 20–50) nor the coincident endothermic phase transition in the main mantle silicates (with a likely Clapeyron slope of –1 to –2 MPa/K) suffice to stagnate slabs. However, together the two provide enough resistance to temporarily stagnate subducting plates, if they subduct accompanied by significant trench retreat. Older, stronger plates are more capable of inducing trench retreat, explaining why backarc spreading and flat slabs tend to be associated with old-plate subduction. Slab viscosities that are ?2 orders of magnitude higher than background mantle (effective yield stresses of 100–300 MPa) lead to similar styles of deformation as those revealed by seismic tomography and slab earthquakes. None of the current transition-zone slabs seem to have stagnated there more than 60 m.y. Since modeled slab destabilization takes more than 100 m.y., lower-mantle entry is apparently usually triggered (e.g., by changes in plate buoyancy). Many of the complex morphologies of lower-mantle slabs can be the result of sinking and subsequent deformation of originally stagnated slabs, which can retain flat morphologies in the top of the lower mantle, fold as they sink deeper, and eventually form bulky shapes in the deep mantle.
DS201901-0035
2017
Garel, F.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.
DS202106-0936
2021
Garel, F.Garel, F., Thoraval, C.Lithosphere as a constant-velocity plate: chasing a dynamical LAB in a homogenous mantle material.Physics of the Earth and Planetary Interiors, Vol. 316, 106710 13p. PdfMantlegeophysics - seismic

Abstract: While the lateral limits of tectonic plates are well mapped by seismicity, the bottom boundary of the lithosphere, the uppermost rigid layer of the Earth comprising both crust and shallow mantle, remains elusive. The lithosphere is usually viewed as consisting of cold, rigid, internally undeformed blocks that translate coherently. The base of the lithosphere, designated as the lithosphere-asthenosphere boundary (LAB), may thus be characterised by different physical fields: temperature, viscosity, strain rate and velocity. The LABs as defined by these different fields are investigated here using thermo-mechanical models of plate and upper mantle dynamics, either in a transient subduction or in a steady-state plate-driven set-up. Mantle material is modelled as homogeneous in composition with a viscosity that depends on temperature, pressure and strain rate. In such a system, the thermo-mechanical transition between lithosphere and asthenosphere occurs over a finite depth interval in temperature, strain rate and velocity. We propose that the most useful dynamical LAB is defined as the base of a “constant-velocity” plate (i.e. the material translating at constant horizontal velocity). The bottom part of this plate deforms at strain rates comparable to those in the underlying asthenosphere mantle: the translating block is not fully rigid. Thermal structure exerts a major control on this dynamical LAB, which deepens with increasing plate age. However, the surface plate velocity, the asthenospheric flow geometry and magnitude also influence the depth of the dynamical LAB, as well as the thickness of the deformed region at the base of the constant-velocity plate. The mechanical transitions from lithosphere to asthenosphere adjust when mantle dynamics evolves. The dynamical and thermo-mechanical LABs occur within a thermal lithosphere-asthenophere gradual transition, similar to the one imaged by geophysical proxies. The concept of a constant-velocity plate can be extended to a constant-velocity subducting slab, which also deforms at its borders and drags the surrounding mantle. This framework is relevant to quantify mass transport within the Earth's mantle.
DS1998-0472
1998
Garfunkel, Z.Garfunkel, Z., Greiling, R.O.A thin orogenic wedge upon thick foreland lithosphere and the missing foreland basin.Geol. Rundsch., Vol. 87, pp. 314-25.Scandinavia, Norway, Sweden, FinlandTectonics, Collisional orogen
DS201412-0053
2014
Garfunkel, Z.Beyth, M., Eyal, Y., Garfunkel, Z.The geology of the northern tip of the Arabian-Nubian shield.Journal of African Earth Sciences, Vol. 99, pp. 332-341.Africa, ArabiaGeology
DS1998-0039
1998
Garg, V.K.Araujo, D.P., Gaspar. J.C., Garg, V.K.The complete phlogopite tetraferri phlogopite series in the Catalao I and II carbonatite complexes, Brasil.7th International Kimberlite Conference Abstract, pp. 29-31.Brazil, GoiasCarbonatite, Deposit - Catalao
DS201312-0297
2013
Gargan, C.R.Gargan, C.R., Curtis, L.A study of heavy minerals from Crater of Diamonds state park, Murfreesboro, Arkansas.Geological Society of America Annual Meeting, Vol. 45, 7, p. 593 abstractUnited States, ArkansasDeposit - Crater of Diamonds
DS201312-0298
2012
Gargi, S.P.Gargi, S.P.Characterizing source reservoirs of igneous rocks: a new perspective. Fractionation of radiogenic isotopes: a new tool for petrogenesis.Chemie der Erde, Vol. 72, pp. 323-332.Australia, Democratic Republic of CongoKimberlites, lamproites
DS201505-0250
2015
Gargiulo, M.F.Ferracutti, G.R., Gargiulo, M.F., Ganuza, M.L., Bjerg, E.A., Castro, S.M.Determination of the spinel group end-members based on electron microprobe analyses.Mineralogy and Petrology, Vol. 109, 2, pp. 153-160.TechnologyGeochronology
DS1993-0948
1993
GariepyMachado, N., David, Scott, Lamothe, Philipe, Gariepyuranium-lead (U-Pb) geochronology of the western Cape Smith Belt: new insights on age of initial rifting and arc magmatismGeological Association of Canada (GAC), Annual Meeting, Vol. 16, p. A78. abstract.Quebec, Ungava, LabradorGeochronology, Tectonics
DS2000-0950
2000
GariepyTelmat, H., Mareschal, Gariepy, David, AntonukCrustal models of the eastern Superior Province, Quebec, derived from new gravity data.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.385-97.QuebecGeophysics - gravity, Tectonics - Superior
DS2002-1420
2002
GariepySchmidberger, S., Simonetti, A., Francis, D., GariepyProbing Archean lithosphere using the Lu Hf isotope systematics of peridotite xenoliths Somerset Island.Earth and Planetary Science Letters, Vol.197,3-4,pp.245-59.Northwest Territories, Somerset IslandCraton, geochronology, Deposit - Nikos
DS1989-0915
1989
Gariepy, 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
Gariepy, C.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
Gariepy, C.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
DS1989-0935
1989
Gariepy, C.Mareschal, J.C., Pinet, C., Gariepy, C., Jaupart, C., Bienfait, G., DallaNew heat flow density and radiogenic heat productiondat a in the Canadian Shield and the QuebecAppalachiansCanadian Journal of Earth Sciences, Vol. 26, No. 4, April pp. 845-852QuebecCraton, Heat Flow
DS1991-0535
1991
Gariepy, C.Gariepy, C., Dupre, B.lead isotopes and crust mantle evolutionMineralogical Association of Canada -Short Course Handbook, Vol. 19, Chapter 6, pp. 191-224GlobalMantle, geochronology, Subduction zones
DS1991-1355
1991
Gariepy, C.Pinet, C., Jaupart, C., Mareschal, J-C., Gariepy, C., Bienfait, G.Heat flow and structure of the lithosphere in the eastern Canadian shieldJournal of Geophysical Research, Vol. 96, No. B12, November 10, pp. 19, 941-19, 963OntarioHeat flow, Crust, greenstone belts
DS1994-0394
1994
Gariepy, C.Davis, W.J., Gariepy, C., Sawyer, E.W.Pre 2.8 Ga crust in the Opatica gneiss belt: a potential source of detrital zircons Abitibi, PontiacGeology, Vol. 22, pp. 111-4.QuebecGeochronology
DS1995-0265
1995
Gariepy, C.Carignan, J., Machado, N., Gariepy, C.uranium-lead (U-Pb) (U-Pb) isotopic geochemistry of komatiites and pyroxenes from the southern Abitibi greenstone belt, CanadaChemical Geology, Vol. 126, No. 1, Nov. 20, pp. 17-28QuebecKomatiites, Abitibi greenstone belt
DS1996-0341
1996
Gariepy, C.Davis, W.J., Gariepy, C., Van Breemen, O.lead isotopic composition of late Archean granites and the extent of recycling early Archean crust Slave ProvinceChemical Geology, Vol. 130, pp. 255-269Northwest TerritoriesGeochronology, Point Lake, Contwoyto Lake, Slave Province
DS1996-1373
1996
Gariepy, C.Stevenson, R., Henry, P., Gariepy, C.Micro-continents and cratons: crustal evolution in the western SuperiorProvince.Geological Association of Canada (GAC) Annual Abstracts, Vol. 21, abstract only p.A91.OntarioCraton, Crustal evolution
DS1998-0614
1998
Gariepy, C.Henry, P., Stevenson, R.K., Gariepy, C.Late Archean mantle composition and crustal growth in the Western Superior Province of Canada: Neodynium and lead ...Geochimica et Cosmochimica Acta, Vol. 62, No. 1, pp. 143-157OntarioGeochronology, Wawa, Wabigoon subprovinces
DS1998-1411
1998
Gariepy, C.Stevenson, R., Henry, P., Gariepy, C.Late Archean cratonic evolutionGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A180. abstract.Ontario, ManitobaSuperior Province, Craton
DS1998-1459
1998
Gariepy, C.Telmat, H., Mareschal, J.C., Gariepy, C., David, J.Crustal models of the northern Superior Province, Quebec, derived from new gravity data.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A183. abstract.QuebecGeophysics - gravity, Nemiscau, la Grande regions
DS1999-0732
1999
Gariepy, C.Telmat, H., Mareschal, J.C., Gariepy, C.The gravity field over the Ungava Bay region from satellite altimetry and new land based data:Canadian Journal of Earth Sciences, Vol. 36, pp. 75-89.Quebec, Labrador, Ungavageophysics - seismic, Leaf Bay - George River
DS1999-0733
1999
Gariepy, C.Telmat, H., Mareschal, J-C, Gariepy, C.The gravity field over Ungava Bay region from satellite altimitry and newland based data: implications geologyCanadian Journal of Earth Sciences, Vol. 36, No. 1, Jan. pp. 75-89.Quebec, Labrador, UngavaGeophysics - gravity
DS2000-0405
2000
Gariepy, C.Henry, P., Stevenson, R.K., Gariepy, C.neodymium isotopic evidence for Early to late Archean (3.4-2.7 Ga) crustal grow thin Western Superior Province OntarioTectonophysics, Vol.322, No.1-2, July10, pp.135-52.OntarioGeochronology, Superior Province
DS2000-0406
2000
Gariepy, C.Henry, P., Stevenson, R.K., Larbi, Y., Gariepy, C.neodymium isotopic evidence for Early to Late Archean (3.4-2.7Ga) crustal growth in Western Superior ProvinceTectonophysics, Vol. 322, No. 1-2, pp.135-51.OntarioGeochronology, Tectonics
DS2002-0284
2002
Gariepy, C.Cheng, L.Z., Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., RadigonSimultaneous inversion of gravity and heat flow data: constraints on thermal regimeJournal of Geodynamics, Vol. 34, 1, pp. 11-30.Ontario, ManitobaGeothermometry, Lithosphere - Abitibi subprovince, Thompson Belt
DS2002-1355
2002
Gariepy, C.Rolandone, F., Jaupart, C., Mareschal, J.C., Gariepy, C., Bienfait, G., CarbonneSurface heat flow, crustal temperatures and mantle heat flow in the Proterozoic TransJournal of Geophysical Research, Vol. 107, No. 12, Dec. 12, 10.1029/2001JB000698Northwest Territories, Alberta, Saskatchewan, OntarioGeothermometry, Heat flow - tectonics
DS2003-1177
2003
Gariepy, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gariepy, C., Bienfait, G., CarbonneSurface heat flow, crustal temperatures and mantle heat flow in the Proterozoic TransJournal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001JB000698OntarioGeothermometry
DS200412-1682
2003
Gariepy, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gariepy, C., Bienfait, G., Carbonne, C., Lapointe, R.Surface heat flow, crustal temperatures and mantle heat flow in the Proterozoic Trans Hudson Orogen, Canadian Shield.Journal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001 JB000698Canada, OntarioGeothermometry
DS200512-0686
2005
Gariepy, C.Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., Fowler, C.M., Bienfait, G., Carbonne, C., Lapointe, R.Heat flow, thermal regime, and elastic thickness of the lithosphere in the Trans-Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 517-532.Canada, Northwest TerritoriesGeothermometry
DS2000-0615
2000
Gariepy, Cheng et al.Mareschal, J.C., Jaupart, Gariepy, Cheng et al.Heat flow and deep thermal structure near the southeastern edge of the Canadian Shield.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.399-414.QuebecGeothermometry, Tectonics
DS1996-0707
1996
Garinan, V.K.Kadryavtseva, G.P., Garinan, V.K., et al.Comparison of the diamond crystals from Arkangelsk and Yakutian kimberliteprovinces.International Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 387.Russia, Arkangelsk, YakutiaDiamond morphology
DS1983-0140
1983
Garinin, V.K.Botkunov, A.I., Garinin, V.K., Kudryavtseva, G.P.Mineral Inclusions in Garnets of Yakutia Kimberlites.(russian)Zap. Vses Mineral. Obshch., (Russian), Vol. 112, No. 3, pp. 311-324RussiaInclusions
DS1992-0694
1992
Garito, A.F.Heflin, J.R., Garito, A.F.Buckministerfullerene: optics beyond the limitsNature, Vol. 356, No. 6366, March 19, p. 192GlobalFullerenes, Optics
DS1996-0481
1996
Garland, F.Garland, F., Turner, S., Hawkesworth, C.Shifts in the source of the Parana basalts through timeLithos, Vol. 37, No. 2/3, April pp. 223-244BrazilBasalts -Parana, Geochemistry
DS2001-0607
2001
Garland, F.G.Kirstein, L.A., Hawkesworth, C.J., Garland, F.G.Felsic lavas or rheomorphic ignimbrites: is there a chemical distinction?Contributions to Mineralogy and Petrology, Vol. 142, No. 3, Dec. pp. 309-22.GlobalIgnimbrites - geochemistry
DS1950-0472
1959
Garland, G.D.Garland, G.D., Bower, M.E.Interpretation of Aeromagnetic Anomalies in Northeastern AlbertaFifth World Petroleum Congress, pp. 787-800.AlbertaGeophysics - Magnetics
DS201808-1774
2018
Garlick, G.Nowicki, T., Garlick, G., Webb, K., Van Eeden, M.Estimation of commercial diamond grades based on microdiamonds: a case study of the Koidu diamond mine, Sierra Leone.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0620-9 11p.Africa, Sierra Leonedeposit - Koidu

Abstract: This paper documents the application of a microdiamond-based approach to the estimation of diamond grade in the Pipe 1 kimberlite at the Koidu mine in Sierra Leone. A geological model of Pipe 1 was constructed to represent the distribution and volume of the dominant kimberlite units within the pipe. Bulk samples, along with representative microdiamond samples, were collected from these units at surface and were used to define the ratio between microdiamond stone frequency (+212 ?m stones per kilogram) and recoverable macrodiamond grade (+1.2 mm carats per tonne; 1 carat?=?0.2 g). These ratios were applied to a comprehensive, spatially representative microdiamond sample dataset and were combined with a spatial model of country-rock xenolith dilution within the pipe to estimate +1.2 mm recoverable grades. The resource estimate was reconciled with subsequent production results in the elevation range 160 to 100 m above sea level. Production results for each of the six 10 m benches covering this elevation range were compared to the estimated average grades for these zones in the pipe. For the five cases where most of the kimberlite mass on a given bench is represented in the production data, the results show a maximum discrepancy of 6% between predicted and reported production grade with no indication of any consistent bias. This indicates that, when supported by a sound geological model and suitable microdiamond and macrodiamond data, the microdiamond-based estimation approach can provide reliable constraints on macrodiamond grade, even in the case of geologically complex bodies such as Koidu Pipe 1.
DS201810-2296
2018
Garlick, G.Bezzola, M., Hetman, C.M., Garlick, G., Creaser, R., Diering, M., Nowicki, T.Geology and resource development of the Kelvin kimberlite pipe, Northwest Territories, Canada.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0631-6 13p.Canada, Northwest Territoriesdeposit - Kelvin

Abstract: The early Cambrian to late Neoproterozoic Kelvin kimberlite pipe is located in the southeast of the Archean Slave Craton in northern Canada, eight km northeast of the Gahcho Kué diamond mine. Kelvin was first discovered in 2000 by De Beers Canada. Subsequent exploration undertaken by Kennady Diamonds Inc. between 2012 and 2016 resulted in the discovery of significant thicknesses of volcaniclastic kimberlite that had not previously been observed. Through extensive delineation drilling Kelvin has been shown to present an atypical, steep-sided inclined L-shaped pipe-like morphology with an overall dip of 15 to 20°. With a surface expression of only 0.08 ha Kelvin dips towards the northwest before turning north. The body (which remains open at depth) has been constrained to a current overall strike length of 700 m with varying vertical thickness (70 to 200 m) and width (30 to 70 m). Detailed core logging, petrography and microdiamond analysis have shown that the pipe infill comprises several phases of sub-horizontally oriented kimberlite (KIMB1, KIMB2, KIMB3, KIMB4, KIMB7 and KIMB8) resulting from multiple emplacement events. The pipe infill is dominated by Kimberley-type pyroclastic kimberlite or “KPK”, historically referred to as tuffisitic kimberlite breccia or “TKB”, with less common hypabyssal kimberlite (HK) and minor units with textures transitional between these end-members. An extensive HK sheet complex surrounds the pipe. The emplacement of Kelvin is believed to have been initiated by intrusion of this early sheet system. The main pipe-forming event and formation of the dominant KPK pipe infill, KIMB3, was followed by late stage emplacement of additional minor KPK and a hypabyssal to transitional-textured phase along the upper contact of the pipe, cross-cutting the underlying KIMB3. Rb-Sr age dating of phlogopite from a late stage phase has established model ages of 531 ± 8 Ma and 546 ± 8 Ma. Texturally and mineralogically, the Kelvin kimberlite is similar to other KPK systems such as the Gahcho Kué kimberlites and many southern African kimberlites; however, the external morphology, specifically the sub-horizontal inclination of the pipe, is unique. The morphology of Kelvin and the other kimberlites in the Kelvin-Faraday cluster defines a new type of exploration target, one that is likely not unique to the Kennady North Project area. Extensive evaluation work by Kennady Diamonds Inc. has resulted in definition of a maiden Indicated Mineral Resource for Kelvin of 8.5 million tonnes (Mt) of kimberlite at an average grade of 1.6 carats per tonne (cpt) with an average diamond value of US$ 63 per carat (ct).
DS1970-0294
1971
Garlick, G.D.Garlick, G.D., Macgregor, I.D., Vogel, D.E.Oxygen Isotope Ratios in Eclogites from KimberlitesScience., Vol. 172, No. 3987, PP. 1025-1027.South AfricaMineralogy
DS1970-0689
1973
Garlick, H.J.Garlick, H.J.Investigation Into the Potential Kimberlite and Carbonatite resources of Australia.London: Msc. Thesis, Royal School Mines, AustraliaBlank
DS1975-1028
1979
Garlick, H.J.Garlick, H.J.Australian Diamond Prospects - the Story So FarIndustrial Minerals, No. 137, PP. 17-29.AustraliaKimberlite
DS1981-0168
1981
Garlick, H.J.Garlick, H.J., Gem Exploration and Minerals Ltd., Suttons Moto.El 1965 Annual Report on ExplorationNorthern Territory Geological Survey Open File Report, No. CR 81/276, 21P.Australia, Northern TerritoryProspecting, Sampling, Geochemistry
DS1981-0169
1981
Garlick, H.J.Garlick, H.J., Pacific Exploration Consultants Pty. Ltd., Gem Exploration and Minerals Ltd.Pine Creek Area, Annual Report on the Gem Joint Venture 1980-1981.Northern Territory Geological Survey, OPEN FILE No. CR 81/270, 16P.Australia, Northern TerritoryKimberlite, Prospecting, Sampling, Geochemistry, Stream Sediment
DS1981-0170
1981
Garlick, H.J.Garlick, H.J., Pacific Exploration Consultants Pty. Ltd., Gem Exploration and Minerals Ltd.El 2255 Pine Creek Area, Annual ReportNorthern Territory Geological Survey Open File., No. CR/277, 17P.Australia, Northern TerritoryProspecting, Geochemistry, Stream Sediment Sampling
DS1981-0171
1981
Garlick, H.J.Garlick, H.J., Pacific Exploration Consultants Pty. Ltd., Gem Exploration and Minerals Ltd.El 1597 Port Keats and Fergusson River Annual Report 1980-81Northern Territory Geological Survey Open File Report, No. CR 81/273, SEPTEMBER 17P.Australia, Northern TerritoryDiamond Prospecting, Geochemistry
DS1982-0217
1982
Garlick, H.J.Garlick, H.J., Gem Exploration and Minerals Ltd., Northern Metals Pty. Ltd.El 25890 Victoria River Nt. Annual Report for 1981Northern Territory Open File., No. CR 82-25, 19P. 5 MAPS. UNPUBL.Australia, Northern TerritoryGeochemistry, Prospecting, Diamonds, Stream Sediment Sampling
DS1982-0218
1982
Garlick, H.J.Garlick, H.J., Gem Exploration and Minerals Ltd., Northern Metals Pty. Ltd.El 2580 Victoria River Area Nt Annual Report 1981Northern Territory Geological Survey Open File., No. CR 82/025, 19P.Australia, Northern TerritoryProspecting, Stream Sediment Sampling, Fitzroy
DS1983-0245
1983
Garlick, H.J.Garlick, H.J.Current Status of the Diamond Exploration Effort in AustraliProceedings of The 5th. Industrial Minerals International Co, PP. 205-219.AustraliaProduction, Prospecting, History
DS1993-0486
1993
Garlick, J.Garlick, J.Lac de Gras Canada's Arctic diamond playIndustrial Minerals, No. 307, April p. 64Northwest TerritoriesNews item, Brief overview -dated
DS1989-0474
1989
Garmany, J.Garmany, J.Accumulations of melt at the base of young oceanic crustNature, Vol. 340, August 24, pp. 628-632. Database # 18138GlobalCrust, MOHO drilling
DS200912-0650
2009
Garnain, V.K.Rubanova, E.V., Garnain, V.K.Multiple stage diamond formation in the Yubileinaya pipe of the Yakutian kimberlite province.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussia, YakutiaDiamond genesis
DS2003-0441
2003
Garneau, P.A.Garneau, P.A.Diavik: turning project into realityQuebec Exploration Conference, Nov. 25-27, 1p. abstractNorthwest TerritoriesDiavik
DS2003-0442
2003
Garneau, P.A.Garneau, P.A.Diavik : turning a project into realityQuebec Exploration 2003, diamond session, extended abstract, 1 pageNorthwest Territoriesmine- Diavik, development update
DS200412-0609
2003
Garneau, P.A.Garneau, P.A.Diavik: turning project into reality.Quebec Exploration Conference, Nov. 25-27, 1p. abstractCanada, Northwest TerritoriesDiavik
DS200712-1037
2006
Garnero, E.Stefan, W., Garnero, E., Renaut, R.A.Signal restoration through deconvolution applied to deep mantle seismic probes.Geophysical Journal International, Vol. 167, 3, Dec. 1, pp. 1353-1362.MantleGeophysics - seismics
DS201312-0397
2014
Garnero, E.Carlson, R.W., Garnero, E., Harrison, T.M., Li, J., Manga, M., McDonough, W.F., Mukhopadhyay, S., Romanowicz, B., Rubie, D., Williams, Q., Zhong, S.Deep time: how did the early Earth become our modern world?Annual Review of Earth and Planetary Sciences, Vol. 42, pp. 151-178.MantleConvection, composition
DS201412-0100
2014
Garnero, E.Carlson, R.W., Garnero, E., Harrison, T.M., Li, J., Manga, M., McDonough, W.F., Mukhopadhyay, S., Romanowicz, B., Rubie, D., Williams, Q., Zhong, S.How did early Earth become our modern world?Annual Review of Earth and Planetary Sciences, Vol. 42, pp. 151-178.MantleMelting
DS1993-0487
1993
Garnero, E.J.Garnero, E.J., et al.Detailed imaging of laterally varying lower mantle structureAmerican Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 557.MantleGeophysics -seismics
DS1996-1546
1996
Garnero, E.J.Williams, Q., Garnero, E.J.Seismic evidence for partial melt at base of Earth's mantleScience, Vol. 273, No. 5281, Sept. 13, pp. 1528-30.MantleGeophysics -seismics, Melt
DS1997-0654
1997
Garnero, E.J.Lay, T., Williams, Q., Garnero, E.J.The core mantle boundaryNature, Vol. 392, No. 6675, Apr. 2, pp. 461-468.MantleBoundary
DS2000-0312
2000
Garnero, E.J.Garnero, E.J.Heterogeneity of the lowermost mantleAnnual Review Earth Plan. Sci., Vol. 28, pp. 509-37.MantleGeochemistry - composition, Tectonics, structure
DS2000-0313
2000
Garnero, E.J.Garnero, E.J., Jeanloz, R.Fuzzy patches on the earth's core mantle boundary?Geophysical Research Letters, Vol. 27, No. 17, Sept. 1, pp. 2777-80.MantleBoundary
DS2000-0546
2000
Garnero, E.J.Kuo, B.Y., Garnero, E.J., Lay, T.Tomographic inversion of S SKS times for shear velocity heterogeneity in D" degree 12 and hybrid models.Journal of Geophysical Research, Vol. 105, No.12, Dec.10, pp.218139-58.MantleTomography
DS200412-1088
2004
Garnero, E.J.Lay, T., Garnero, E.J., Williams, Q.Partial melting in a thermo-chemical boundary layer at the base of the mantle.Physics of the Earth and Planetary Interiors, Vol. 146, 3-4, pp. 441-467.MantleGeothermometry, geochemistry
DS200412-1360
2004
Garnero, E.J.Moore, M.M., Garnero, E.J., Lay, T., Williams, Q.Shear wave splitting and waveform complexity for lowermost mantle structures with low velocity lamellae and transverse isottropyJournal of Geophysical Research, Vol. 109, B2, 10.1029/2003 JB002546MantleGeophysics - seismics
DS200412-1988
2004
Garnero, E.J.Thorne, M.S., Garnero, E.J., Grand, S.P.Geographic correlation between hot spots and deep mantle lateral shear wave velocity gradients.Physics of the Earth and Planetary Interiors, Vol. 146, 1-2, pp. 47-63.MantleGeophysics - seismics, plumes
DS200512-0605
2004
Garnero, E.J.Lay, T., Garnero, E.J.Core mantle boundary structures and processes.Geophysical Monograph, AGU, No. 150, pp. 25-42.MantleGeophysics - seismics
DS200512-0913
2005
Garnero, E.J.Rost, S., Garnero, E.J., Williams, Q., Manga, M.Seismological constraints on a possible plume root at the core mantle boundary.Nature, No. 7042, June 2, pp. 666-669.MantleGeophysics - seismics
DS200612-0612
2006
Garnero, E.J.Hutko, A.R., Lay, T., Garnero, E.J., Revenaugh, J.Seismic detection of folded, subducted lithosphere at the core mantle boundary.Nature, Vol. 441, 7091, May 18, pp. 333-336.MantleGeophysics - seismics
DS200612-1521
2006
Garnero, E.J.Wenk, H-R., Speziale, S., McNamara, A.K., Garnero, E.J.Modeling lower mantle anistropy development in a subducting slab.Earth and Planetary Science Letters, Vol. 245, 1-2, pp. 302-314.MantleSubduction
DS200712-0349
2007
Garnero, E.J.Garnero, E.J., Lay, T., McNamara, A.Implications of lower mantle structural heterogeneity for the existence and nature of whole mantle plumes.Plates, plumes and Planetary Processes, pp. 79-102.MantleStructure
DS200712-0950
2007
Garnero, E.J.Schmerr, N., Garnero, E.J.Upper mantle discontinuity topography from thermal and chemical heterogeneity.Science, Vol. 318, 5850, Nov. 24, pp. 623-625.MantleGeothermometry
DS200812-0387
2008
Garnero, E.J.Garnero, E.J., McNamara, A.K.Structure and dynamics of Earth's lower mantle.Science, Vol. 320, 5876, May 2, pp. 626-628.MantleGeodynamics - geophysics - seismics
DS200812-0497
2008
Garnero, E.J.Hutko, A.R., Lay, T., Revenaugh, J., Garnero, E.J.Anticorrelated seismic velocity anomalies from post perovskite in the lowermost mantle.Science, No. 5879, May 23, pp. 1070-1973.MantleGeophysics - seismics
DS200812-0740
2008
Garnero, E.J.Mercier, J-P., Bostock, M.G., Audet, P., Gaherty, J.B., Garnero, E.J., Revenaugh, J.The teleseismic signature of fossil subduction: northwestern Canada. (part of Lithoprobe)Journal of Geophysical Research, Vol. 113, B 04308Canada, Northwest TerritoriesGeophysics - seismics
DS200812-0975
2008
Garnero, E.J.Rost, S., Garnero, E.J., Williams, Q.Seismic array detection of suducted oceanic crust in the lower mantle.Journal of Geophysical Research, Vol. 113, B06303MantleGeophysics - seismics
DS200912-0495
2009
Garnero, E.J.Mercier, J.P., Bostock, M.G., Cassidy, J.F., Dueker, K., Gaherty, J.B., Garnero, E.J., Revenaugh, ZandtBody wave tomography of western Canada.Tectonophysics, Vol. 475, 2, pp. 480-492.Canada, Alberta, British Columbia, Northwest TerritoriesGeophysics - seismics
DS201012-0425
2010
Garnero, E.J.Lassak, T.M., McNamara, A.K., Garnero, E.J., Zhong, S.Core mantle boundary topography as a possible constraint on lower mantle chemistry and dynamics.Earth and Planetary Science Letters, Vol. 289, pp. 232-241.MantleConvection, plumes
DS201012-0488
2010
Garnero, E.J.McNamara, A.K., Garnero, E.J., Rost, S.Tracking deep mantle reservoirs with ultra low velocity zones.Earth and Planetary Science Letters, Vol. 299, 1-2, Oct. 15, pp. 1-9.MantleGeophysics - seismics
DS201412-0508
2014
Garnero, E.J.Li, M., McNamara, A.K., Garnero, E.J.Chemical complexity of hotspots caused by cycling oceanic crust through mantle reservoirs.Nature Geoscience, Vol. 7, pp. 366-370.MantleHotspots
DS201412-0702
2014
Garnero, E.J.Pommier, A., Garnero, E.J.Petrology based modeling of mantle melt electrical conductvity and joint interpretation of electromagnetic and seismic results.Journal of Geophysical Research,, Vol. 119, 5, pp. 4001-4016.MantleGeophysics - EM, Seismics
DS201608-1405
2016
Garnero, E.J.Garnero, E.J., McNamara, A.K., Shim, S-H.Continent sized anomalous zones with low seismic velocity at the base of Earth's mantle.Nature Geoscience, Vol. 9, 7, pp. 481-489.MantleGeophysics - seismics

Abstract: Seismic images of Earth's interior reveal two massive anomalous zones at the base of the mantle, above the core, where seismic waves travel slowly. The mantle materials that surround these anomalous regions are thought to be composed of cooler rocks associated with downward advection of former oceanic tectonic plates. However, the origin and composition of the anomalous provinces is uncertain. These zones have long been depicted as warmer-than-average mantle materials related to convective upwelling. Yet, they may also be chemically distinct from the surrounding mantle, and potentially partly composed of subducted or primordial material, and have therefore been termed thermochemical piles. From seismic, geochemical and mineral physics data, the emerging view is that these thermochemical piles appear denser than the surrounding mantle materials, are dynamically stable and long-lived, and are shaped by larger-scale mantle flow. Whether remnants of a primordial layer or later accumulations of more-dense materials, the composition of the piles is modified over time by stirring and by chemical reactions with material from the surrounding mantle, underlying core and potentially from volatile elements transported into the deep Earth by subducted plates. Upwelling mantle plumes may originate from the thermochemical piles, so the unusual chemical composition of the piles could be the source of distinct trace-element signatures observed in hotspot lavas.
DS201706-1069
2017
Garnero, E.J.Frost, D.A., Rost, S., Garnero, E.J., Li, M.Seismic evidence for Earth's crusty deep mantle.Earth and Planetary Science Letters, Vol. 470, pp. 54-63.Mantlegeophysics - seismic

Abstract: Seismic tomography resolves anomalies interpreted as oceanic lithosphere subducted deep into Earth's lower mantle. However, the fate of the compositionally distinct oceanic crust that is part of the lithosphere is poorly constrained but provides important constraints on mixing processes and the recycling process in the deep Earth. We present high-resolution seismic array analyses of anomalous P-waves sampling the deep mantle, and deterministically locate heterogeneities in the lowermost 300 km of the mantle. Spectral analysis indicates that the dominant scale length of the heterogeneity is 4 to 7 km. The heterogeneity distribution varies laterally and radially and heterogeneities are more abundant near the margins of the lowermost mantle Large Low Velocity Provinces (LLVPs), consistent with mantle convection simulations that show elevated accumulations of deeply advected crustal material near the boundaries of thermo-chemical piles. The size and distribution of the observed heterogeneities is consistent with that expected for subducted oceanic crust. These results thus suggest the deep mantle contains an imprint of continued subduction of oceanic crust, stirred by mantle convection and modulated by long lasting thermo-chemical structures. The preferred location of the heterogeneity in the lowermost mantle is consistent with a thermo-chemical origin of the LLVPs. Our observations relate to the mixing behaviour of small length-scale heterogeneity in the deep Earth and indicate that compositional heterogeneities from the subduction process can survive for extended times in the lowermost mantle.
DS201801-0009
2017
Garnero, E.J.Coltice, N., Larrouturou, G., Debayle, E., Garnero, E.J.Interactions of scales of convection in the Earth's mantle.Tectonophysics, in press available, 9p.Mantleplate tectonics, geophysics - seismics

Abstract: The existence of undulations of the geoid, gravity and bathymetry in ocean basins, as well as anomalies in heat flow, point to the existence of small scale convection beneath tectonic plates. The instabilities that could develop at the base of the lithosphere are sufficiently small scale (< 500 km) that they remain mostly elusive from seismic detection. We take advantage of 3D spherical numerical geodynamic models displaying plate-like behavior to study the interaction between large-scale flow and small-scale convection. We find that finger-shaped instabilities develop at seafloor ages > 60 Ma. They form networks that are shaped by the plate evolution, slabs, plumes and the geometry of continental boundaries. Plumes impacting the boundary layer from below have a particular influence through rejuvenating the thermal lithosphere. They create a wake in which new instabilities form downstream. These wakes form channels that are about 1000 km wide, and thus are possibly detectable by seismic tomography. Beneath fast plates, cold sinking instabilities are tilted in the direction opposite to plate motion, while they sink vertically for slow plates. These instabilities are too small to be detected by usual seismic methods, since they are about 200 km in lateral scale. However, this preferred orientation of instabilities below fast plates could produce a pattern of large-scale azimuthal anisotropy consistent with both plate motions and the large scale organisation of azimuthal anisotropy obtained from recent surface wave models.
DS201806-1250
2018
Garnero, E.J.Shule, Yu, Garnero, E.J.Ultralow velocity zone locations: a global assessment.Geochemistry, Geophysics, Geosystems, Vol. 19, 2, pp. 396-414.Mantlecore, boundary

Abstract: We have compiled all previous ultralow velocity zone (ULVZ) studies, and digitized their core?mantle boundary (CMB) sampling locations. For studies that presented sampling locations based on infinite frequency ray theory, we approximated Fresnel zones onto a 0.5° × 0.5° grid. Results for these studies were separated according to wave type: (1) core?reflected phases, which have a single location of ULVZ sampling (ScS, ScP, PcP), (2) core waves that can sample ULVZs at the core entrance and exit locations of the wave (e.g., SPdKS, PKKP, and PKP), and (3) waves which have uncertainties of ULVZ location due to long CMB sampling paths, e.g., diffracted energy sampling over a broad region (Pdiff, Sdiff). For studies that presented specific modeled ULVZ geographical shapes or PKP scatter probability maps, we digitized the regions. We present summary maps of the ULVZ coverage, as well as published locations arguing against ULVZ presence. A key finding is that there is not a simple mapping between lowermost mantle reduced tomographic velocities and observed ULVZ locations, especially given the presence of ULVZs outside of lowermost mantle large low velocity provinces (LLVPs). Significant location uncertainty exists for some of the ULVZ imaging wave types. Nonetheless, this compilation supports a compositionally distinct origin for at least some ULVZs. ULVZs are more likely to be found near LLVP boundaries, however, their relationship to overlying surface locations of hot spots are less obvious. The new digital ULVZ database is freely available for download.
DS201901-0020
2018
Garnero, E.J.Coltice, N., Larrouturou, G., Debayle, E., Garnero, E.J.Interactions of scales of convection in the Earth's mantle.Tectonophysics, Vol. 746, pp. 669-677.Mantleconvection

Abstract: The existence of undulations of the geoid, gravity and bathymetry in ocean basins, as well as anomalies in heat flow, point to the existence of small scale convection beneath tectonic plates. The instabilities that could develop at the base of the lithosphere are sufficiently small scale (< 500 km) that they remain mostly elusive from seismic detection. We take advantage of 3D spherical numerical geodynamic models displaying plate-like behavior to study the interaction between large-scale flow and small-scale convection. We find that finger-shaped instabilities develop at seafloor ages > 60 Ma. They form networks that are shaped by the plate evolution, slabs, plumes and the geometry of continental boundaries. Plumes impacting the boundary layer from below have a particular influence through rejuvenating the thermal lithosphere. They create a wake in which new instabilities form downstream. These wakes form channels that are about 1000 km wide, and thus are possibly detectable by seismic tomography. Beneath fast plates, cold sinking instabilities are tilted in the direction opposite to plate motion, while they sink vertically for slow plates. These instabilities are too small to be detected by usual seismic methods, since they are about 200 km in lateral scale. However, this preferred orientation of instabilities below fast plates could produce a pattern of large-scale azimuthal anisotropy consistent with both plate motions and the large scale organisation of azimuthal anisotropy obtained from recent surface wave models.
DS200412-0610
2004
Garnero, J.Garnero, J.Geophysics: a new paradigm for Earth's core-mantle boundary.Science, Vol. 304, 5672, May 7, p. 834-5.MantleBoundary
DS200612-1179
2006
Garneto, E.J.Rost, S., Garneto, E.J.Detection of an ultralow velocity zone at the core mantle boundary using diffracted PKKPab waves.Journal of Geophysical Research, Vol. 111, B7 B07309.MantleGeophysics - seismics
DS1992-0515
1992
Garnett, R.H.T.Garnett, R.H.T.Recent developments in offshore diamond mining in southern AfricaVarik Enterprises Inc, 9p. Handout at Mining Analysts meeting Oct. 27thNamibiaPlacers, alluvials, Marine mining
DS1992-0516
1992
Garnett, R.H.T.Garnett, R.H.T.Components of a recovery factor in gold and tin dredgingTransactions of the Institute of Mining and Metallurgy (IMM), Vol. 100, pp. A121-A145Southern AfricaAlluvial mining, Gold and tin -with some aspects for diamonds
DS1995-0584
1995
Garnett, R.H.T.Garnett, R.H.T.A diamond resource acquisition strategy in AfricaProspectors and Developers Association of Canada (PDAC) Annual Meeting, p. 58. abstractAfrica, South AfricaReview
DS1995-0585
1995
Garnett, R.H.T.Garnett, R.H.T.Offshore diamond mining in southern Africaá#1Mining Engineering, Vol. 47, No. 8, August pp. 738-744.South Africa, NamibiaAlluvials, Overview of areas - exploration
DS1996-0482
1996
Garnett, R.H.T.Garnett, R.H.T.Mineral recovery performance in marine miningOffshore Technology Conference, 27th., pp. 465-474.GlobalMarine mining, placers, Mineral processing, sampling
DS1996-0483
1996
Garnett, R.H.T.Garnett, R.H.T.Offshore diamond mining in southern Africa #2Offshore Technology Conference, 27th., pp. 71-86.South Africa, NamibiaMarine mining, placers, Methodology
DS1996-0484
1996
Garnett, R.H.T.Garnett, R.H.T.Estimation of marine mineral reservesOffshore Technology Conference, 27th., pp. 573-587.South Africa, NamibiaMarine mining, placers, Ore reserves, estimation, kriging
DS1997-0370
1997
Garnett, R.H.T.Garnett, R.H.T.Placer evaluation: a reply to Peter RichMinerals Industry International, May, pp. 23-27GlobalEconomics, Placers, alluvials, evaluation, reserves
DS1998-0473
1998
Garnett, R.H.T.Garnett, R.H.T.Marine diamond mining - now an established industry29th. Annual Underwater Mining Institute, 1p. abstractGlobalMarine mining
DS1998-0474
1998
Garnett, R.H.T.Garnett, R.H.T.Risks in marine diamond mining - lessons from the past and present29th. Annual Underwater Mining Institute, 1p. abstractNamibia, South AfricaMarine mining
DS1999-0236
1999
Garnett, R.H.T.Garnett, R.H.T.Recent developments in marine diamond mining #2Prospectors and Developers Association of Canada (PDAC) abstract volume, p. 8, 9.Namibia, South AfricaOverview, Marine mining
DS1999-0237
1999
Garnett, R.H.T.Garnett, R.H.T.Recent developments in marine diamond mining #1Prospectors and Developers Association of Canada (PDAC) preprint, 12p.Namibia, South AfricaMarine mining
DS2002-0502
2002
Garnett, R.H.T.Garnett, R.H.T.Economically important geological characteristics of marine placersGeological Society of America Annual Meeting Oct. 27-30, Abstract p. 443.GlobalAlluvial - diamonds
DS2002-0503
2002
Garnett, R.H.T.Garnett, R.H.T.Recent development in marine diamond miningMarine Resources & Geotechnology, Vol. 20, 3, pp. 137-160.GlobalPlacers, alluvials, Technology - mineral processing diamonds
DS201608-1406
2015
Garnett, R.H.T.Garnett, R.H.T.Graphical presentation of production versus estimates in placer mining. Diamonds mentioned.Applied Earth Science Transactions Institute of Mining and Metallurgy, Vol. 124, 3, pp. 175-190.GlobalAlluvials, reserves
DS1860-0937
1896
Garnier, J.Garnier, J., Garnier, P.L'or et le Diamant Au Transvaal et Au CapParis: Baudry, From Pp. 327-357 of Memoir De Soc. Ing. Civil, 33P.Africa, South Africa, Cape Province, TransvaalDiamond Genesis
DS1860-0986
1897
Garnier, J.Garnier, J.Gold and Diamonds in the Transvaal and the CapeGeological Society of South Africa Transactions, Vol. 2, PP. 91-103; PP. 109-120.Africa, South Africa, Cape Province, TransvaalGeology
DS200812-0388
2008
Garnier, J.Garnier, J., Quantin, C., Guimaraes, E., Bequer, T.Can chromite weathering be a source of Cr in soils?Mineralogical Magazine, Vol. 72, 1, pp. 49-53.TechnologyChromite - not specific to diamonds
DS1860-0937
1896
Garnier, P.Garnier, J., Garnier, P.L'or et le Diamant Au Transvaal et Au CapParis: Baudry, From Pp. 327-357 of Memoir De Soc. Ing. Civil, 33P.Africa, South Africa, Cape Province, TransvaalDiamond Genesis
DS1995-0586
1995
Garratt, R.G.Garratt, R.G., Thorleifseon, L.H.Kimberlite indicator minerals and till geochemistry reconnaisance in southern Saskatchewan.Geological Survey of Canada Bulletin, No. .. 30p.SaskatchewanGeochemistry, Kimberlite
DS201412-0548
2014
Garrdo, C.J.Marchesi, C., Dale, C.W., Garrdo, C.J., Pearson, D.G., Bosch, D., Bodinier, J-L., Gervilla, F., Hidas, K.Fractionation of highly siderophile elements in refertilized mantle: implications for the Os isotope composition of basalts.Earth and Planetary Science Letters, Vol. 400, pp. 33-44.MantleRonda peridotite
DS1950-0512
1959
Garrels, R.M.Week, A.D., Garrels, R.M.Geologic Setting of the Colorado Plateau Ores. In: Geochemistry and Mineralogy of Colorado Plateau Uranium Ores.United States Geological Survey (USGS) PROF. PAPER., No. 320, PT. 1, PP. 3-11.Colorado PlateauKimberlite, Rocky Mountains
DS1996-0903
1996
GarrettMatile, G.L.D., Nielsen, E., Thorleifson, L.H., GarrettKimberlite indicator mineral analysis from the West lake Plain: follow up to Geological Society of Canada (GSC) Prairie kimberlite study.Man. Geological Survey Open File, No. 96-2, 39p.ManitobaGeochemistry - exploration, Westlake Plain
DS1860-0699
1891
Garrett, F.E.Garrett, F.E.In Afrikaanderland and the Land of Ophir. Being Notes and Sketches in Political, Social and Financial South Africa.London: Pall Mall Gazette., No. 58, PP. VIII-96. APPROX. 99P.Africa, South Africa, ZimbabweHistory
DS200712-0350
2007
Garrett, M.Garrett, M., Bercovici, D.On the dynamics of a hydrous melt layer above the transition zone.Journal of Geophysical Research, Vol. 112, B7, B07401MantleMelting
DS200712-0351
2007
Garrett, M.Garrett, M., Bercovici, D.On the dynamics of a hydrous melt layer above the transition zone.Journal of Geophysical Research, Vol. 112, B7, B07401MantleMelting
DS1960-0664
1966
Garrett, R.G.Garrett, R.G.Regional Geochemical Reconnaissance of Eastern Sierra LeoneLondon: Ph.d. Thesis, University London., 201P.Sierra Leone, West AfricaRegional Studies
DS1960-0826
1967
Garrett, R.G.Garrett, R.G., Nichol, I.Regional Geochemical Reconnaissance in Eastern Sierra LeoneInstitute of Mining and Metallurgy. Transactions, Vol. 76, PP. B97-112.Sierra Leone, West AfricaGeochemistry
DS1989-0475
1989
Garrett, R.G.Garrett, R.G., Davis, J.C.Report on the working group 6- artificial intelligence in theEarthsciencesGeological Society of Canada (GSC) Paper Proceedings of the Colloquiium of Statistical applications in the, Preprint, 9p. Database # 17596GlobalComputer, GIS - Artificial intelligence
DS1991-0536
1991
Garrett, R.G.Garrett, R.G., Thorleifson, L.H.Prairie kimberlite study - soil, till geochemistry and mineralogy - low density orientation survey traverse.Geological Survey of Canada (GSC) Open File, No. 2685ManitobaGeochemistry - exploration
DS1993-0488
1993
Garrett, R.G.Garrett, R.G.Another cry from the heart.. trying to answer some queries.... how many samples do I need..Explore, No. 81, October pp. 9, 10, 11, 12, 13, 14, 15GlobalGeochemistry, Sampling techniques, problems
DS1993-0489
1993
Garrett, R.G.Garrett, R.G., Thorleifson, L.H.Prairie kimberlite study -soil and till geochemistry and mineralogy, lowdensity orientation survey traverses Winnipeg-Calgary-Edmonton-WinnipegGeological Survey Canada Open File, No. 2685, 1 disc. $ 15.00SaskatchewanGeochemistry, Kimberlite indicator minerals and site locations
DS1993-0490
1993
Garrett, R.G.Garrett, R.G., Thorleifson, L.H.Prairie indicator mineral and soil geochemical surveyThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin) , Annual Meeting Abstracts approximately 10 lines, Vol. 86, No. 968, March POSTER ABSTRACT p. 69Saskatchewan, AlbertaGeomorphology, Geochemistry
DS1993-1602
1993
Garrett, R.G.Thorleifson, L.H., Garrett, R.G.Kimberlite indicator mineral reconnaissance of the Canadian PraireMan. Geological Survey Convention '93, p. 31. abstractManitobaGeochemistry - exploration
DS1993-1603
1993
Garrett, R.G.Thorleifson, L.H., Garrett, R.G.Prairie kimberlite study -till matrix geochemistry and preliminary indicator mineral data.Geological Survey of Canada Open File, No. 2745, 1 disk. $ 15.00 Geological Society of Canada (GSC).Saskatchewan, Manitoba, AlbertaGeochemistry, Kimberlite indicator minerals
DS1994-0577
1994
Garrett, R.G.Garrett, R.G., Thorleifson, I.H.Kimberlitic indicator mineral reconnaissance of the Canadian PrairiesGeological Survey of Canada Open Forum January 17-19th. Abstracts only, p. 17.Alberta, Saskatchewan, ManitobaGeochemistry, Indicator minerals
DS1994-1773
1994
Garrett, R.G.Thorleifson, L.H., Garrett, R.G.Kimberlite indicator mineral reconnaissance of the Canadian Praire : update 1994.Man. Geological Survey Convention '94, p. abstractManitobaGeochemistry - exploration
DS1994-1774
1994
Garrett, R.G.Thorleifson, L.H., Garrett, R.G., Matile, G.Prairie kimberlite study: indicator mineral geochemistryGeological Survey of Canada Open file, No. 2875Alberta, Western CanadaGeochemistry
DS1994-1775
1994
Garrett, R.G.Thorlieffson, L.H., Garrett, R.G., Matile, G.Prairie kimberlite study - indicator mineral geochemistryGeological Survey of Canada Open File, No. 2875, 1 disc. $ 15.00SaskatchewanGeochemistry, Indicator minerals
DS1995-0587
1995
Garrett, R.G.Garrett, R.G., Thorleifson, L.H.Kimberlite indicator mineral and till geochemical reconnaissance southernSaskatchewan.Geological Survey of Canada Open File, No. 3119, pp. 227-254.SaskatchewanGeochemistry -Diamond exploration techniques, Kimberlite
DS1996-0485
1996
Garrett, R.G.Garrett, R.G., Thorleifson, L.H.The provenance of Prairie tills and its importance in mineral explorationSaskatchewan Minexpo'96 Symposium, p. 24. abstractSaskatchewanGeochemistry, Kimberlite indicator minerals
DS1996-0486
1996
Garrett, R.G.Garrett, R.G., Thorleifson, L.H.Relationship of drift provenance and soil forming processes to mineral exploration in the Prairies.Geological Survey of Canada Colloquium, Jan. 22-24th., Poster display onlySaskatchewan, AlbertaExploration, Geomorphology
DS1996-0487
1996
Garrett, R.G.Garrett, R.G., Thorleifson, L.H.Kimberlite indicator mineral and soil geochemical reconnaissance of the Canadian Prairie region.Geological Survey of Canada, LeCheminant ed, OF 3228, pp. 205-211.Saskatchewan, AlbertaGeochemistry, Mineral sampling -indicators
DS1996-0902
1996
Garrett, R.G.Matile, G., Nielsen, E., Thorleifson, H., Garrett, R.G.Follow up kimberlite indicator mineral survey of western ManitobaGeological Survey of Canada Colloquium, Jan. 22-24th., Poster display onlyManitobaExploration, Geomorphology, geochemistry
DS1997-1154
1997
Garrett, R.G.Thorleifson, L.H., Garrett, R.G.Kimberlite indicator mineral and geochemical reconnaissance of southernAlberta.Geological Survey of Canada, Bulletin. No. 500, pp. 209-234.AlbertaGeochemistry, Indicator minerals
DS2000-0954
2000
Garrett, R.G.Thorleifson, L.H., Garrett, R.G.Lithology, mineralogy and geochemistry of glacial sediments overlying kimberlite at Smeaton, SaskatchewanGeological Survey of Canada (GSC) Bulletin., No. 551, 40p. $ 17.90SaskatchewanExploration, Deposit - Smeaton area
DS2003-0443
2003
Garrett, R.G.Garrett, R.G., Grunsky, E.C.S and R functions for the display of Thompson Howarth plotsComputers and Geosciences, Vol. 29, 2, pp. 239-42.GlobalComputer - program
DS200412-0611
2003
Garrett, R.G.Garrett, R.G., Grunsky, E.C.S and R functions for the display of Thompson Howarth plots.Computers & Geosciences, Vol. 29, 2, pp. 239-42.TechnologyComputer - program
DS200812-0389
2008
Garrett, R.G.Garrett, R.G., Reiman, C., Smith, D.B., Xie, X.From geochemical prospecting to international geochemical mapping: a historical overview.Geochemistry, Exploration Environment Analysis, Vol. 8, 3-4, pp. 205-217.TechnologyGeochemistry
DS201412-0567
2013
Garrett, R.G.McClenaghan, M.B., Plouffe, A., McMartin, I., Campbell, J.E., Spirito, W.A., Paulen, R.C., Garrett, R.G., Hall, G.E.M.Till sampling and geochemical analytical protocols used by the Geological Survey of Canada.Geochemistry: Exploration, Environment, Analysis, Vol. 13, pp. 285-301.TechnologySampling
DS2000-0196
2000
GarridoCunha, J.C., Mascarenhas, Silva, Garrido, SampaioIntegrated airborne geophysical and geological studies of the Mundo Novo greenstone belt, Bahia, Brasil.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, BahiaCraton - Sao Francisco, Mobile belt
DS200812-0867
2008
Garrido, C.Pearson, D.G., Kjarsgaard, B.A., Garrido, C., Nixon, P.H.The Ronda peridotite and lamproites in Spain. Salmeron, Jumill, Cerro Canbezo Maria. Chemical analyses of lamproite/ Isotopic systematics of lamproites.9th. IKC Field Trip Guidebook, CD 38p.Europe, SpainGuidebook - lamproites
DS201112-0888
2011
Garrido, C.Ruiz Cruz, M.D., Saz de Galdeano, C., Garrido, C.Electron back scatter diffraction based identification and quantification of diamonds from the RIF gneisses ( Spain and Morocco): economic implications.Economic Geology, Vol. 06, pp. 1241-1249.Europe, Spain, Africa, MoroccoBeni-Bousera, Cabo Negro, Ceuta
DS1998-0475
1998
Garrido, C.J.Garrido, C.J., Bodinier, J.L.Distribution of trace elements in minerals from anhydorus spinel peridotites and websterites...RondaMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 498-9.GlobalMelt-peridotite, large-ion lithophile elements (LILE) rare earth elements (REE) HFSE reservoirs in subcontinental lithosphere
DS1999-0238
1999
Garrido, C.J.Garrido, C.J., Bodinier, J.L.Diversity of mafic rocks in the Ronda peridotite: evidence - pervasive melt rock reaction during heatingJournal of Petrology, Vol. 40, No. 5, May, pp. 729-54.MantleSubcontinental lithosphere, Upwelling asthenosphere
DS2000-0314
2000
Garrido, C.J.Garrido, C.J., Bodinier, J.L., Alard, O.Incompatible trace element partioning and residence in anhydrous spinel peridotites and websterites from RondaEarth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.327-40.GlobalPeridotites, Deposit - Ronda
DS2000-0567
2000
Garrido, C.J.Lenoir, X., Garrido, C.J., Bodinier, J.L., Dautria, J-M.Contrasting lithospheric mantle domains beneath the Massif Central revealed by geochemistry peridotite...Earth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.359-75.FranceXenoliths - geochemistry
DS2001-1198
2001
Garrido, C.J.Vauchez, A., Garrido, C.J.Seismic properties of an asthenospherized lithospheric mantle: constraints from lattic preferred orientationsEarth and Planetary Science Letters, Vol. 192, No. 2, pp. 235-49.SpainPeridotites, Rhonda Massif
DS200812-0917
2007
Garrido, C.J.Precigout, J., Gueydan, F., Gapais, D., Garrido, C.J., Eassaifi, A.Strain localization in the subcontinental mantle ?? a ductile alternative to the brittle mantle.Tectonophysics, Vol. 445, 3-4, pp. 318-336.MantleSubduction
DS201012-0473
2010
Garrido, C.J.Marchesi, C., Griffin, W.L., Garrido, C.J., Bodinier, J-L., O'Reilly, S.Y., Pearson, N.J.Persistence of mantle lithospheric Re-Os signature during asthenospherization of the subcontinental lithospheric mantle: insights in situ sulphides....Contributions to Mineralogy and Petrology, Vol. 159, 3, pp. 315-330.Europe, SpainRonda peridotite
DS201212-0208
2012
Garrido, C.J.Frets, E., Tommasi, A., Garrido, C.J., Padron-Navarta, J.A., Amri, I., Targuisti, K.Deformation processes and rheology of pyroxenites under lithospheric mantle conditions.Journal of Structural Geology, Vol. 39, pp. 138-157.Europe, Africa, MoroccoWebsterite, Beni-Bousera
DS201312-0320
2013
Garrido, C.J.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
DS201312-0574
2013
Garrido, C.J.Marchesi, C., Garrido, C.J., Bosch, D., Bodinier, J-L., Gervilla, F., Hidas, K.Mantle refertilization by melts of crustal derived garnet pyroxenite: evidence from the Ronda Peridotite massif, southern Spain.Earth and Planetary Interiors, Vol. 362, pp. 66-75.Europe, SpainRonda - pyroxenite. Melts
DS201412-0253
2014
Garrido, C.J.Frets, E.C., Tommasi, A., Garrido, C.J., Vauchez, A., Mainprice, D., Targuisti, K., Amri, I.The Beni Boussera peridotite ( Rif belt, Morocco): an oblique slip low angle shear zone thinning the subcontinental mantle lithosphere.Journal of Petrology, Vol. 55, 2, pp. 283-313.Africa, MoroccoPeridotite
DS201610-1850
2016
Garrido, C.J.Chetoumani, K., Bondinier, J-L., Garrido, C.J., Marchesi, C., Amri, I., Targusiti, K.Spatial variability of pyroxenite layers in the Beni Bousera orogenic peridotite ( Morocco) and implications for their origin.Comptes Rendus Geoscience, in press available 11p.Africa, MoroccoPeridotite

Abstract: The Beni Bousera peridotite contains a diversity of pyroxenite layers. Several studies have postulated that at least some of them represent elongated strips of oceanic lithosphere recycled in the convective mantle. Some pyroxenites were, however, ascribed to igneous crystal segregation or melt-rock reactions. To further constrain the origin of these rocks, we collected 171 samples throughout the massif and examined their variability in relation with the tectono-metamorphic domains. A major finding is that all facies showing clear evidence for a crustal origin are concentrated in a narrow corridor of mylonitized peridotites, along the contact with granulitic country rocks. These peculiar facies were most likely incorporated at the mantle-crust boundary during the orogenic events that culminated in the peridotite exhumation. The other pyroxenites derive from a distinct protolith that was ubiquitous in the massif before its exhumation. They were deeply modified by partial melting and melt-rock reactions associated with lithospheric thinning.
DS201704-0650
2016
Garrido, C.J.Varas-Reu, M.I., Garrido, C.J., Marchesi, C., Bodinier, J-L., Frets, E., Bosch, D., Tommasi, A., Hidas, K., Targuisti, K.Refertilization processes of the subcontinental lithospheric mantle: the record of the Beni Bousera orogenic peridotite ( Rif Belt, northern Morocco).Journal of Petrology, Vol. 57, 11-12, pp. 2251-2270.Africa, MoroccoDeposit - Beni Bousera

Abstract: Correlations between major and minor transition elements in tectonically emplaced orogenic peridotites have been ascribed to variable degrees of melt extraction and melt-rock reaction processes, leading to depletion or refertilization. To elucidate how such processes are recorded in the subcontinental lithospheric mantle, we processed a large geochemical dataset for peridotites from the four tectono-metamorphic domains of the Beni Bousera orogenic massif (Rif Belt, northern Morocco). Our study reveals that variations in bulk-rock major and minor elements, Mg-number and modal mineralogy of lherzolites, as well as their clinopyroxene trace element compositions, are inconsistent with simple partial melting and mainly resulted from different reactions between melts and depleted peridotites. Up to 30% melting at <3 GPa and cryptic metasomatism can account for the geochemical variations of most harzburgites. In Grt-Sp mylonites, melting and melt-rock reactions are masked by tectonic mixing with garnet pyroxenites and subsolidus re-equilibration. In the rest of the massif, lherzolites were mostly produced by refertilization of a refractory protolith (Mg-number = 91, Ol = 70%, Cpx/Opx = 0.4) via two distinct near-solidus, melt- rock reactions: (1) clinopyroxene and orthopyroxene precipitation and olivine consumption at melt/rock ratios <0.75 and variable mass ratio between crystallized minerals and infiltrated melt ®, which are recorded fairly homogeneously throughout the massif; (2) dissolution of orthopyroxene and precipitation of clinopyroxene and olivine at melt/rock ratios <1 and R = 0.2-0.3, which affected mainly the Arie` gite-Seiland and Seiland domains. The distribution of secondary lherzolites in the massif suggests that the first refertilization reaction occurred prior to the differentiation of the Beni Bousera mantle section into petro-structural zones, whereas the second reaction was associated with the development of the tectono-metamorphic domains. Our data support a secondary, refertilization-related origin for most lherzolites in orogenic peridotite massifs.
DS201707-1314
2016
Garrido, C.J.Chetouani, K., Bodinier, J-L., Garrido, C.J., Marchesi, C., Amri, I., Targuisti, K.Spatial variability of pyroxenite layers in the Beni Bousera orogenic peridotite ( Morocco) and implications for their origin.Comptes Rendus Geoscience, Vol. 348, pp. 619-629.Africa, Moroccoperidotite

Abstract: The Beni Bousera peridotite contains a diversity of pyroxenite layers. Several studies have postulated that at least some of them represent elongated strips of oceanic lithosphere recycled in the convective mantle. Some pyroxenites were, however, ascribed to igneous crystal segregation or melt–rock reactions. To further constrain the origin of these rocks, we collected 171 samples throughout the massif and examined their variability in relation with the tectono-metamorphic domains. A major finding is that all facies showing clear evidence for a crustal origin are concentrated in a narrow corridor of mylonitized peridotites, along the contact with granulitic country rocks. These peculiar facies were most likely incorporated at the mantle–crust boundary during the orogenic events that culminated in the peridotite exhumation. The other pyroxenites derive from a distinct protolith that was ubiquitous in the massif before its exhumation. They were deeply modified by partial melting and melt–rock reactions associated with lithospheric thinning.
DS201806-1258
2018
Garrido, C.J.Varas-Reus, M.I., Garrido, C.J., Marchesi, C., Bosch, D., Hidas, K.Genesis of ultra-high pressure garnet pyroxenites in orogenic peridotites and its bearing on the compositional heterogeneity of the Earth's mantle. Ronda, Beni BouseraGeochimica et Cosmochimica Acta, Vol. 232, pp. 303-328.Africa, Morocco, Europe, SpainUHP

Abstract: We present an integrated geochemical study of ultra-high pressure (UHP) garnet pyroxenites from the Ronda and Beni Bousera peridotite massifs (Betic-Rif Belt, westernmost Mediterranean). Based on their Sr-Nd-Pb-Hf isotopic systematics, we classify UHP garnet pyroxenites into three groups: Group A pyroxenites (Al 2 O 3 : 15-17.5 wt. %) have low initial 87 Sr/ 86 Sr, relatively high ? Nd , ? Hf and 206 Pb/ 204 Pb ratios, and variable 207 Pb/ 204 Pb and 208 Pb/ 204 Pb. Group B pyroxenites (Al 2 O 3 < 14 wt. %) are characterized by high initial 87 Sr/ 86 Sr and relatively low ? Nd , ? Hf and 206 Pb/ 204 Pb ratios. Group C pyroxenites (Al 2 O 3 ~ 15 wt. %) have depleted radiogenic signatures with relatively low initial 87 Sr/ 86 Sr and 206 Pb/ 204 Pb, high ? Nd and ? Hf , and their 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios are similar to those of Group B pyroxenites. The major and trace element and isotopic compositions of UHP garnet pyroxenites support their derivation from ancient (1.5-3.5 Ga) oceanic crust recycled into the mantle and intimately stirred with peridotites by convection. However, the genesis of these pyroxenites requires also the involvement of recycled continental lower crust with an isotopic composition akin to the lower crustal section of the lithosphere where these UHP garnet pyroxenites now reside in. These oceanic and continental crustal components were stirred in different proportions in the convective mantle, originating pyroxenites with a more marked geochemical imprint of either oceanic (Group A) or continental lower crust (Group B), or hybrid compositions (Group C). The pyroxenite protoliths likely underwent several melting events, one of them related to the formation of the subcontinental lithospheric mantle and continental crust, generating restitic UHP garnet pyroxenites now preserved in the Ronda and Beni Bousera orogenic peridotites. The extent of melting was mostly 3 controlled by the bulk Mg-number (Mg#) of the pyroxenite protoliths, where protoliths with low Mg# experienced higher degrees of partial melting than sources with higher Mg#. Positive Eu and Sr anomalies in bulk rocks, indicative of their origin from cumulitic crustal gabbros, are preserved mostly in high Mg# pyroxenites due to their higher melting temperatures and consequent lower partial melting degrees. The results of this study show that the genesis of UHP garnet pyroxenites in orogenic peridotites requires a new recipe for the marble cake mantle hypothesis, combining significant recycling and stirring of both oceanic and continental lower crust in the Earth's mantle. Furthermore, this study establishes a firm connection between the isotopic signatures of UHP pyroxenite heterogeneities in the mantle and the continental lower crust.
DS201808-1794
2018
Garrido, C.J.Varas-Reu, M.I., Garrido, C.J., Marchesi, C., Bosch, D., Hidas, K.Genesis of ultra high pressure garnet pyroxenites in orogenic peridotites and its bearing on the compositional heterogeneity of the Earth's mantle.Geochimica et Cosmochimica Acta, Vol. 232, pp. 303-328.Mantledeposit - Ronda, Beni Bousera

Abstract: We present an integrated geochemical study of ultra-high pressure (UHP) garnet pyroxenites from the Ronda and Beni Bousera peridotite massifs (Betic-Rif Belt, westernmost Mediterranean). Based on their Sr-Nd-Pb-Hf isotopic systematics, we classify UHP garnet pyroxenites into three groups: Group A pyroxenites (Al2O3: 15-17.5?wt.%) have low initial 87Sr/86Sr, relatively high ?Nd, ?Hf and 206Pb/204Pb ratios, and variable 207Pb/204Pb and 208Pb/204Pb. Group B pyroxenites (Al2O3?
DS201904-0744
2019
Garrido, C.J.Hidas, K., Garrido, C.J., Booth-Rea, G., Marchesi, C., Bodinier, J-L., Dautria, J-M., Louni-Hacini, A., Azzouni-Sekkal, A.Lithosphere tearing along STEP faults and synkenetic formation of lherzolite and wehrlite in the shallow subcontinental mantle. OranSolid Earth, https://doi.org/10.5194 /se-2019-32 36p.Mantle, Africa, Algeriasubduction

Abstract: Subduction-Transform Edge Propagator (STEP) faults are the locus of continual lithospheric tearing at slab edges, resulting in sharp changes in the lithospheric and crustal thickness and triggering lateral and/or near-vertical mantle flow. However, the mechanisms at the lithospheric mantle scale are still poorly understood. Here, we present the microstructural study of olivine-rich lherzolite, harzburgite and wehrlite mantle xenoliths from the Oran volcanic field (Tell Atlas, NW Algeria). This alkali volcanic field occurs along a major STEP fault responsible for the Miocene westward slab retreat in the westernmost Mediterranean. Mantle xenoliths provide a unique opportunity to investigate the microstructures in the mantle section of a STEP fault system. The microstructures of mantle xenoliths show a variable grain size ranging from coarse granular to fine-grained equigranular textures uncorrelated with modal variations. The major element composition of the mantle peridotites provides temperature estimates in a wide range (790-1165?°C) but in general, the coarse-grained and fine-grained peridotites suggest deeper and shallower provenance depth, respectively. Olivine grain size in the fine-grained peridotites depends on the size and volume fraction of the pyroxene grains, which is consistent with pinning of olivine grain growth by pyroxenes as second phase particles. In the coarse-grained peridotites, well-developed olivine crystal preferred orientation (CPO) is characterized by orthorhombic and [100]-fiber symmetries, and orthopyroxene has a coherent CPO with that of olivine, suggesting their coeval deformation by dislocation creep at high-temperature. In the fine-grained microstructures, along with the weakening of the fabric strength, olivine CPO symmetry exhibits a shift towards [010]-fiber and the [010]- and [001]-axes of orthopyroxene are generally distributed subparallel to those of olivine. These data are consistent with deformation of olivine in the presence of low amounts of melts and the precipitation of orthopyroxenes from a melt phase. The bulk CPO of clinopyroxene mimics that of orthopyroxene via a topotaxial relationship of the two pyroxenes. This observation points to a melt-related origin of most clinopyroxenes in the Oran mantle xenoliths. The textural and geochemical record of the peridotites are consistent with interaction of a refractory harzburgite protolith with a high-Mg# melt at depth (resulting in the formation of coarse-grained clinopyroxene-rich lherzolite and wehrlite), and with a low-Mg# evolved melt in the shallow subcontinental lithospheric mantle (forming fine-grained harzburgite). We propose that pervasive melt-peridotite reaction - promoted by lateral and/or near-vertical mantle flow associated with lithospheric tearing - resulted in the synkinematic crystallization of secondary lherzolite and wehrlite and played a key effect on grain size reduction during the operation of the Rif-Tell STEP fault. Melt-rock reaction and secondary formation of lherzolite and wehrlite may be widespread in other STEP fault systems worldwide.
DS201911-2526
2019
Garrido, C.J.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.
DS202102-0181
2020
Garrido, C.J.Dilissen, N., Hidas, K., Garrido, C.J., Kahl, W-A., Sanchez-Vizcaino, V.L.Graphical abstract: Morphological transition during prograde olivine growth formed by high-pressure dehydration of antigorite-serpentinite to chlorite-harzburgite in a subduction setting.Lithos, doi. 10.1016/j. lithos.2020.105949 1p. PdfMantlesubduction

Abstract: Crystal morphologies are essential for deciphering the reaction history of igneous and metamorphic rocks because they often record the interplay between nucleation and growth rates controlled by the departure from equilibrium. Here, we report an exceptional record of the morphological transition of olivine formed during subduction metamorphism and high-pressure dehydration of antigorite-serpentinite to prograde chlorite-harzburgite in the Almirez ultramafic massif (Nevado-Filábride Complex, Betic Cordillera, SE Spain). In this massif, rare varied-textured chlorite-harzburgite (olivine+enstantite+chlorite+oxides) —formed after high-P dehydration of antigorite-serpentinite— exhibits large olivine porphyroblasts made up of rounded cores mantled by coronas of tabular olivine grains, similar to single tabular olivines occurring in the matrix. The correlative X-ray ?-CT and EBSD study of two varied-textured chlorite-harzburgite samples show that tabular olivine in coronas is tabular on (100)Ol with c > b >> a, and grew in nearly the same crystallographic orientation as the rounded olivine cores of the porphyroblast. Quantitative textural analysis and mass balance indicate that varied-textured chlorite-harzburgite is the result of a two-stage nucleation and growth of olivine during the progress of the high-P dehydration of antigorite-serpentinite to chlorite-harzburgite reaction. The first stage occurred under a low affinity (?Gr) and affinity rate (?Gr/dt) of the antigorite dehydration reaction that resulted in a low time-integrated nucleation rate and isotropic growth of olivine, forming rounded olivine porphyroblasts. With further progress of the dehydration reaction, a second stage of relatively higher affinity and affinity rate resulted in a higher time-integrated nucleation rate of olivine coeval with a shift from isotropic to anisotropic olivine growth, leading to tabular olivines. The two-stage evolution resulted in olivine porphyroblasts made up of rounded cores mantled by coronas of tabular olivine grains characteristic of varied-texture chlorite-harzburgite. Although a switch to anisotropic tabular olivine in the second stage is consistent with the relative increase in the affinity and affinity rate, these changes cannot solely account for the growth of Almirez olivine tabular on (100). Tabular olivines in komatiites and other igneous rocks are tabular on (010)Ol with either a > c >> b, or a ? c > > b, in agreement with experimentally determined growth rates of olivine phenocrysts under moderate to high undercooling and cooling rates. On the other hand, olivine tabular on (100) is expected in the presence of highly polymerized fluids where inhibited growth of the olivine (100) and (010) interfaces occurs, respectively, due to dissociative and molecular adsorption of water monolayers. Rounded and tabular olivines in Almirez varied-textured chlorite-harzburgite show differing trace element compositions that we interpret as due to the infiltration of external fluids during antigorite dehydration. Isothermal infiltration of highly polymerized fluids would explain the shift in the affinity and affinity rate of the antigorite dehydration reaction, as well as the olivine morphology tabular on (100) due to the inhibited growth on the (100) and, to a lesser extent, (010). Our study shows that surface-active molecules may play an essential role in shaping the morphology of growing crystals during fluid-present metamorphic crystallization.
DS202205-0715
2022
Garrido, J.Seals, J., Lenardic, A., Garrido, J.Plate tectonics, mixed heating convection and the divergence.Researchgate preprint, 12p. PdfMantleplate tectonics

Abstract: Petrological data indicate that upper mantle and mantle plume temperatures diverged 2.5 billion years ago. This has been interpreted as plate tectonics initiating at 2.5 Ga with Earth operating as a single plate planet before then. We take an Occam’s razor view that the continuous operation of plate tectonics can explain the divergence. We validate this hypothesis by comparing petrological data to results from mixed heating mantle convection models in a plate tectonic mode of mantle cooling. The comparison shows that the data are consistent with plate tectonics operating over geologic history.
DS1980-0002
1980
Garrison, J.R.JR.Agee, J., Garrison, J.R.JR., Taylor, L.A.Kimberlites: a Window Into the Mantle Beneath the Southeastern Appalachians #1Geological Society of America (GSA), Vol. 12, No. 4, P. 169. (abstract.).Appalachia, VirginiaGeology
DS1980-0003
1980
Garrison, J.R.JR.Agee, J.J., Garrison, J.R.JR., Taylor, L.A.Kimberlites: a Window Into the Mantle Beneath the Southeastern Appalachians #2Eos, Vol. 61, No. 17, P. 412, (abstract.).Appalachia, KentuckyGeology
DS1980-0137
1980
Garrison, J.R.Jr.Garrison, J.R.Jr., Taylor, L.A.Megacrysts and Xenoliths in Kimberlite-elliott County, Kentucky.Contributions to Mineralogy and Petrology, Vol. 75, PP. 27-42.United States, Appalachia, KentuckyPetrography, Crustal Xenoliths
DS1980-0138
1980
Garrison, J.R.Jr.Garrison, J.R.Jr., Taylor, L.A.Oxide-pyroxene Intergrowths from Kimberlite and Cumulate Rocks Co- Precipitation or Exsolution?Geological Society of America (GSA), Vol. 12, No. 7, P. 431. (abstract.).United States, Appalachia, KentuckyXenoliths, Petrography, Genesis
DS1980-0139
1980
Garrison, J.R.JR.Garrison, J.W., Garrison, J.R.JR., Taylor, L.A.Kimberlite Metasomatism; Wall Rock Alterations from a Hot Intrusive at Elliott County, Kentucky.Eos, Vol. 61, No. 46, P. 1156. (abstract.).United States, Central States, KentuckyAlteration
DS1981-0172
1981
Garrison, J.R.Jr.Garrison, J.R.Jr.Mineralogy and Petrology of Hydrous Groundmass Minerals And altered Crustal Clasts in Kimberlite, Elliott County, Kentucky.Msc. Thesis, University Tennessee, Knoxville., United States, Kentucky, AppalachiaKimberlite, Mineralogy, Petrology
DS1981-0173
1981
Garrison, J.R.Jr.Garrison, J.R.Jr., Taylor, L.A.Petrogenesis of Pyroxene Oxide Intergrowths from Kimberlite and Cumulate Rock; Co-precipitation or Exsolution?American Mineralogist., Vol. 66, No. 7-8, PP. 723-740.United States, Kentucky, South Carolina, PennsylvaniaBlank
DS1982-0001
1982
Garrison, J.R.JR.Agee, J.J., Garrison, J.R.JR., Taylor, L.A.Petrogenesis of Oxide Minerals in Kimberlite, Elliott County, Kentucky.American Mineralogist., Vol. 67, No. 1-2, PP. 28-42.GlobalIlmenite, Petrography, Microprobe
DS1986-0269
1986
Garrison, J.R.Jr.Garrison, J.R.Jr.Evolution of South margin of North America: Proterozoic rocks of Texas, Oklahoma, New MexicoGeological Society of America (GSA) Abstract Volume, Vol. 18, No. 6, p. 608. (abstract.)Midcontinent, Texas, Oklahoma, New MexicoBlank
DS1980-0139
1980
Garrison, J.W.Garrison, J.W., Garrison, J.R.JR., Taylor, L.A.Kimberlite Metasomatism; Wall Rock Alterations from a Hot Intrusive at Elliott County, Kentucky.Eos, Vol. 61, No. 46, P. 1156. (abstract.).United States, Central States, KentuckyAlteration
DS1995-0588
1995
Garrit, D.Garrit, D., Griffin, W.L., O'Reilly, S.Y.Archean and Proterozoic mantle in west GreenlandProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 179-80.GreenlandMantle, Geobarometry
DS1996-0488
1996
Garrit, D.Garrit, D., Griffin, W.L., O'Reilly, S.Y.Processes in Archean and Proterozooic mantle in West GreenlandV.m. Goldschmidt Conference, Held March 31, 1p. abstractGreenlandKimberlite dykes, Paleogeotherms
DS2000-0315
2000
Garrit, D.Garrit, D.The nature of Archean and Proterozoic lithospheric mantle and lower crust in West Greenland illustrated by the geochemistry and petrography of xenoliths from kimberlPh.D. Thesis University of Copenhangen, Denmark, 289p.GreenlandXenoliths
DS1994-1617
1994
Garson, D.Sinclair, W.D., Richardson, J.M., Heagy, A.E., Garson, D.Mineral deposits of Canada -preliminary map and deposit listGeological Survey of Canada Open file, No. 2874, 34p. 1 disk. total cost $ 47.30CanadaMineral deposit listing, Map
DS1994-0578
1994
Garson, D.F.Garson, D.F., Jefferson, C.W., Kerwill, J.A., et al.Mineral potential map of the northern Slave Province NTS 76, 86, a data-driven spatial modelling prototype for the mineral resources map of the Northwest Territories.Geological Survey of Canada Open Forum January 17-19th. Abstracts only, p. 17.Northwest TerritoriesMap, GIS
DS1975-0356
1976
Garson, M.S.Mitchell, A.H.G., Garson, M.S.Mineralization at Plate BoundariesMinerals Sci. Eng., Vol. 8, No. 2, PP. 129-169.Angola, Central Africa, Southwest Africa, NamibiaGenesis, Structure, Tectonics
DS1981-0301
1981
Garson, M.S.Mitchell, A.H.G., Garson, M.S.Mineral Deposits and their Global Tectonic SettingAcademic Press, 405P. DIAMONDS SEE PAGING LISTS IN CONT.South Africa, Russia, Yakutia, East Africa, Angola, Australia, BrazilClassification, Distribution, Origin, Genesis, Placers, Pipes
DS1984-0292
1984
Garson, M.S.Garson, M.S., Coats, J.S., Rock, N.M.S., Deans, T.Fenites, Breccia Dykes, Albitites and Carbonatitic Veins Near the Great Glen Fault, Inverness, Scotland.Journal of the Geological Society of London., Vol. 141, PP. 711-732.ScotlandRelated Rocks
DS1985-0218
1985
Garson, M.S.Garson, M.S.Relationship of Carbonatites to Plate TectonicsIndian Mineralogist, Sukheswala Volume, pp. 163-168IndiaCarbonatite
DS1987-0141
1987
Garson, M.S.Dawson, J.B., Garson, M.S., Roberts, B.Altered former alkalic carbonatite lava from Oloinyo Lengai,Tanzania:inferences for calcite carbonatite lavasGeology, Vol. 15, No. 8, August, pp. 765-768TanzaniaAlkaline rocks, Geochemistry
DS201112-0440
2011
Gartner, A.Hofmann, M., Linnemann, U., Rai, V., Becker, S., Gartner, A., Sagawe, A.The India and South Chin a cratons at the margin of Rodinia - synchronous Neoproterozoic magmatism revealed by LA-ICP-MS zircon analyses.Lithos, In press available 65p.India, ChinaMagmatism
DS201412-0271
2014
Gartner, A.Gartner, A., Linnemann, U., Hofmann, M.The provenance of northern Kalahari Basin sediments and growth history of the southern Congo Craton reconstructed by U-Pb ages of zircons from recent river sands.International Journal of Earth Sciences, Vol. 103, 2, pp. 579-595.Africa, Southern AfricaGeochronology
DS201412-0367
2014
Gartner, A.Hofmann, M., Linnemann, U., Hoffmann, K-H., Gerdes, A., Eckelmann, K., Gartner, A.The Namuskluft and Dreigratberg sections in southern Namibia ( Kalahari Craton, Gariep Belt): a geological history of Neoproterozoic rifting and recycling of cratonic crust during the dispersal of Rodinia until the amalgamation of Gondwana.International Journal of Earth Sciences, Vol. 103, pp. 1187-1202.Africa, NamibiaGeochronology
DS1997-0371
1997
Gartrell, A.P.Gartrell, A.P.Evolution of rift basins and low angle detachments in multilayer analogmodelsGeology, Vol. 25, No. 7, July pp. 615-618GlobalBasin analysis, Models
DS200412-1761
2004
Gartz, V.Schmitz, M.D., Bowring, S.A., De Wit, M.J., Gartz, V.Subduction and terrane collision stabilize the western Kaapvaal Craton tectosphere 2.9 billion years ago.Earth and Planetary Science Letters, Vol. 222, 2, pp. 363-376.Africa, South AfricaSubduction, tectonics, continental lithosphere
DS1975-0514
1977
Gartzos, E.T.Gartzos, E.T.The geology and petrology of the Iron and Manitou Island Alkaline carbonatite complexes at Nipissing Lake, OntarioPh.d. thesis, McMaster Univ, Pages unknownOntarioIron, Manitou, Carbonatite
DS200512-1228
2004
Garuti, G.Zaccarini, F., Stumpfl, E.F., Garuti, G.Zirconolite and Zr Th U minerals in chromities of the Finero complex, western Alps, Italy: evidence for carbonatite type metasomatism in a subcontinental ... mantle plume.Canadian Mineralogist, Vol. 42, 6, pp. 1825-1858.Europe, ItalyMantle plume, carbonatite
DS200712-1212
2007
Garuti, G.Zaccarini, F., Thalhammer, O.A.R., Princivalle, F., Lenaz, D., Stanley, C.J., Garuti, G.Djerfisherite in the Guli dunite complex, Polar Siberia: a primary or metasomatic phase?Canadian Mineralogist, Vol. 45, 5, Oct. pp. 1201-1211.RussiaMetasomatism
DS201412-0272
2014
Garven, E.A.Garven, E.A., Novy, L., Koop, G.2013 geotechnical investigation at the Long Lake containment facility, at Ekati diamond mine.2014 Yellowknife Geoscience Forum, p. 40, abstractCanada, Northwest TerritoriesDeposit - Ekati
DS1995-0589
1995
Garven, G.Garven, G.Continental scale groundwater flow and geologic processesAnnual Review of Earth Planetary Sciences, Vol. 23, pp. 89-118MantleGroundwater flow
DS1999-0438
1999
Garven, G.Majorowicz, J.A., Garven, G., Jessop, A., Jessop, C.Present heat flow along a profile across the Western Canada sedimentary basin; the extent hydrodynamic...Geothermics in Basin Analysis, Merriam Ed., pp. 61-79.Alberta, Western CanadaGeothermometry, Basin
DS201012-0534
2010
Garvie, L.Nemeth, P., Garvie, L., Buseck, P.R.Challenges of identifying diamond polytypes of natural nanodiamonds.International Mineralogical Association meeting August Budapest, abstract p. 797.TechnologyMeteorite
DS201412-0273
2014
Garvie, L.A.J.Garvie, L.A.J., Nemeth, P., Buseck, P.R.Transformation of graphite to diamond via a topotactic mechanism. Gujba ( meteorite)American Mineralogist, Vol. 99, pp. 531-538.TechnologyCrystallography
DS202011-2056
2020
Garvie, L.A.J.Nemeth, P., McColl, K., Garvie, L.A.J., Salzmann, C.Complex nanostructures in diamond. Nature Materials, doi:10.1038/s4 1563-020-0759-8 7p. PdfGlobalmeteorites, synthetics

Abstract: Meteoritic diamonds and synthesized diamond-related materials contain a wide variety of complex nanostructures. This Comment highlights and classifies this structural complexity by a systematic hierarchical approach, and discusses the perspectives on nanostructure and properties engineering of diamond-related materials.
DS201412-0152
2014
Garvie, O.Cronwright, H., Garvie, O.The MSA microdiamond and heavy mineral analysis laboratory: the first independent ISO17025 accredited facility in Africa.GSSA Kimberley Diamond Symposium and Trade Show provisional programme, Sept. 10-12, POSTERTechnologyMineral analyses laboratory
DS1981-0174
1981
Garvie, O.G.Garvie, O.G.The Surface Textures on Pyrope, Picroilmenite and Chrome Diopside from Kimberlite.Msc. Thesis, University Cape Town., 132P.BotswanaJwaneng, Mineral Chemistry, Microprobe, Kelyphite
DS1982-0219
1982
Garvie, O.G.Garvie, O.G., Robinson, D.N.The mineralogy, structure and mode of formation of kelphite and associated sub-kelphite surfaces on pyropeTerra Cognita, Vol. 2, pp. 229-30.GlobalMineralogy - Alteration, Kimberlites
DS1984-0293
1984
Garvie, O.G.Garvie, O.G., Robinson, D.N.The Formation of Kelyphite and Associated Sub-kelyphitic And Sculptured Surfaces on Pyrope from Kimberlite.Proceedings of Third International Kimberlite Conference., Vol. 1, PP. 371-382.South Africa, BotswanaMineral Chemistry, Garnet, Analyses
DS1989-1406
1989
Garvie, O.G.Smith, C.B., Allsopp, H.L., Garvie, O.G., Kramers, J.D., JacksonNote on the uranium-lead (U-Pb) (U-Pb) perovskite method for dating kimberlites: examples fromChemical Geology, Vol. 79, pp. 137-145South Africa, Northwest TerritoriesGeochronology, Perovskite
DS200712-0352
2007
Garvie, O.G.Garvie, O.G.The use of surface textures on kimberlitic indicators recovered by a client from their Kasai diamonds project Kasai Craton, DRC, central Africa.Diamonds in Kimberley Symposium & Trade Show, Bristow and De Wit held August 23-24, Kimberley, South Africa, GSSA Diamond Workshop CD slides 14Africa, Democratic Republic of CongoExploration - techniques
DS201612-2324
2014
Garvies, L.A.J.Nemeth, P., Garvies, L.A.J., Aoki, T., Dubrovinskaia, N., Dubrovinsky, L.Londaleite is faulted and twinned cubic diamond and does not exist as a discrete material.Nature Communications, Nov. 10p. * note dateTechnologyLonsdaleite

Abstract: Lonsdaleite, also called hexagonal diamond, has been widely used as a marker of asteroidal impacts. It is thought to play a central role during the graphite-to-diamond transformation, and calculations suggest that it possesses mechanical properties superior to diamond. However, despite extensive efforts, lonsdaleite has never been produced or described as a separate, pure material. Here we show that defects in cubic diamond provide an explanation for the characteristic d-spacings and reflections reported for lonsdaleite. Ultrahigh-resolution electron microscope images demonstrate that samples displaying features attributed to lonsdaleite consist of cubic diamond dominated by extensive {113} twins and {111} stacking faults. These defects give rise to nanometre-scale structural complexity. Our findings question the existence of lonsdaleite and point to the need for re-evaluating the interpretations of many lonsdaleite-related fundamental and applied studies.
DS1991-0537
1991
Garvin, L.Garvin, L.Mantle plumes: smoke signals from the deepNature, Vol. 351, No. 6329, June 27, pp. 699-701GlobalMantle, Plumes
DS1995-0590
1995
Garvin, L.Garvin, L.Reflections on plate tectonicsNature, Vol. 375, June 22, p. 632MantleTectonics
DS1988-0237
1988
Garwin, L.Garwin, L.Mass extinction: of impacts and volcanoesNature, Vol. 336, No. 6201, December 22, pp. 714-715GlobalExtinction controversy
DS1991-0538
1991
Garwin, L.Garwin, L.Smoke signals from the deepNature, Vol. 351, No. 6329, June 27, pp. 699-701GlobalCrust, Subduction zones
DS1995-0591
1995
Garwin, L.Garwin, L.Reflections on plate tectonicsNature, Vol. 375, June 22, p. 632.MantleTectonics - plate
DS2002-0504
2002
Garwin, S.Garwin, S.The geologic setting of intrusion related hydrothermal systems near Batu Hijau porphyry copper gold depositSociety of Economic Geologists Special Publication, No.9,pp.333-66.Indonesia, SumbawaGold, metallogeny, Deposit - Batu Hijau
DS1991-1138
1991
Garwood, B.L.Meyer, H.O.A., Garwood, B.L., Svisero, D.P.The Pantano intrusionFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 59-64BrazilGeology, Ultrabasic alkaline intrusion
DS1993-1025
1993
Garwood, B.L.Meyer, H.O.A., Waldman, M.A., Garwood, B.L.Mantle xenoliths from kimberlite, Kirkland Lake area, OntarioGeological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A99 abstract onlyOntarioXenoliths, Garnet Lherzolites
DS1994-1180
1994
Garwood, B.L.Meyer, H.O.A., Garwood, B.L., Svisero, D.P., Smith, C.B.Alkaline intrusions of western Minas GeraisProceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 140-155.BrazilAlkaline rocks, Minas Gerais region
DS1994-1182
1994
Garwood, B.L.Meyer, H.O.A., Waldman, M.A., Garwood, B.L.Mantle xenoliths from kimberlite near Kirkland Lake, OntarioCanadian Mineralogist, Vol. 32, No. 2, June pp. 295-306.OntarioXenoliths, garnet lherzolite, Deposit -C-14 kimberlite
DS1998-0476
1998
Garza, R.S.M.Garza, R.S.M., Acton, G.D., Geissman, J.W.Carboniferous through Jurassic paleomagnetic dat a and their bearing on rotation of the Colorado Plateau.Journal of Geophysical Research, Vol. 103, No. B10, Oct. 10, pp. 24179-88.Colorado PlateauGeophysics - paleomagnetics, Tectonics
DS201412-0274
2014
Garzanti, E.Garzanti, E., Resentini, A., Ando, S., Vezzoli, G., Pereira, A., Vermeesch, P.Physical controls on sand and composition and relative durability of detrital minerals during ultra-long distance littoral and aeolian transport ( Namibia and southern Angola).Sedimentology, Vol. 62, 4, pp. 971-996.Africa, Namibia, AngolaDiamondiferous littoral deposits
DS201802-0238
2018
Garzanti, E.Garzanti, E., Dinis, P., Vermeesch, P., Ando, S., Hahn, A., Huvi, J., Limonta, M., Padoan, M., Resentini, A., Rittner, M., Vezzoli, G.Sedimentary processes controlling ultralong cells of littoral transport: placer formation and termination of the Orange sand highway in southern Angola.Sedimentology, Vol. 65, 2, pp. 431-460.Africa, Angolaplacers, alluvials

Abstract: This study focuses on the causes, modalities and obstacles of sediment transfer in the longest cell of littoral sand drift documented on Earth so far. Sand derived from the Orange River is dragged by swell waves and persistent southerly winds to accumulate in four successive dunefields in coastal Namibia to Angola. All four dunefields are terminated by river valleys, where aeolian sand is flushed back to the ocean; and yet sediment transport continues at sea, tracing an 1800 km long submarine sand highway. Sand drift would extend northward to beyond the Congo if the shelf did not become progressively narrower in southern Angola, where drifting sand is funnelled towards oceanic depths via canyon heads connected to river mouths. Garnet-magnetite placers are widespread along this coastal stretch, indicating systematic loss of the low-density feldspatho-quartzose fraction to the deep ocean. More than half of Moçamedes Desert sand is derived from the Orange River, and the rest in similar proportions from the Cunene River and from the Swakop and other rivers draining the Damara Orogen in Namibia. The Orange fingerprint, characterized by basaltic rock fragments, clinopyroxene grains and bimodal zircon-age spectra with peaks at ca 0•5 Ga and ca 1•0 Ga, is lost abruptly at Namibe, and beach sands further north have abundant feldspar, amphibole-epidote suites and unimodal zircon-age spectra with a peak at ca 2•0 Ga, documenting local provenance from Palaeoproterozoic basement. Along with this oblique-rifted continental margin, beach placers are dominated by Fe-Ti-Cr oxides with more monazite than garnet and thus have a geochemical signature sharply different from beach placers found all the way along the Orange littoral cell. High-resolution mineralogical studies allow us to trace sediment dispersal over distances of thousands of kilometres, providing essential information for the correct reconstruction of ‘source to sink’ relationships in hydrocarbon exploration and to predict the long-term impact of man-made infrastructures on coastal sediment budgets.
DS200412-1720
2004
Garzione, C.N.Saha, A., Basu, A.R., Garzione, C.N., Bandyopadhyay, P.K., Chakrabarti, A.Geochemical and petrological evidence for subduction accretion processes in the Archean eastern Indian Craton.Earth and Planetary Science Letters, Vol. 220, 1-2, March 30, pp. 91-106.IndiaTectonics, petrology, geochronology
DS200712-0741
2007
Garzione, C.N.Molnar, P., Garzione, C.N.Bounds on the viscosity coefficient of continental lithosphere from removal of mantle lithosphere beneath the Altiplano and Eastern Cordillera.Tectonics, Vol. 26, 2, TC2013South AmericaTectonics
DS200612-1429
2006
GasanovTitkov, 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
DS200712-1084
2006
GasanovTitkov, 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
DS201312-0792
2013
Gasc, J.Schubnel, A., Brunet, F., Hilairet, N., Gasc, J., Wang, Y., Green, H.W.II.Deep focus earthquake analogs recorded at high pressure and temperature in the laboratory.Science, Vol. 341, no. 6152, pp. 1377-1380. Sept. 20TechnologySubduction
DS201605-0838
2016
Gaschnig, R.M.Gaschnig, R.M., Rudnick, R.L., McDonough, W.F., Kaufman, A.J., Valley, J., Hu, Z., Gao, S., Beck, M.L.Compositional evolution of the upper continental crust through time, as constrained by ancient glacial diamictites.Geochimica et Cosmochimica Acta, in press available 78p.MantleBulk chemistry

Abstract: The composition of the fine-grained matrix of glacial diamictites from the Mesoarchean, Paleoproterozoic, Neoproterozoic, and Paleozoic, collected from four modern continents, reflect the secular evolution of the average composition of the upper continental crust (UCC). The effects of localized provenance are present in some cases, but distinctive geochemical signatures exist in diamictites of the same age from different localities, suggesting that these are global signatures. Archean UCC, dominated by greenstone basalts and less so komatiites, was more mafic, based on major elements and transition metal trace elements. Temporal changes in oxygen isotope ratios, rare earth elements, and high field strength elements indicate that the UCC became more differentiated and that tonalite-trondhjemite-granodiorite suites became less important with time, findings consistent with previous studies. We also document the concentrations of siderophile and chalcophile elements (Ga, Ge, Cd, In, Sn, Sb, W, Tl, Bi) and lithophile Be in the UCC through time, and use the data for the younger diamictites to construct a new estimate of average UCC along with associated uncertainties.
DS1986-0270
1986
Gascon, C.P.Gascon, C.P.Support of remote sensing to diamond prospecting.*SPAGeominas, *SPA., Vol. 15, pp. 5-15VenezuelaRemote sensing
DS1910-0185
1911
Gascoyne, R.Gascoyne, R.The Transvaal Diamond Mining IndustryMining Eng. World., Vol. 35, JULY 8TH. PP. 53-56.South Africa, TransvaalCurrent Activities, Locations
DS200812-1097
2008
Gasharova, B.Sommer, H., Regenauer Lieb, K., Hauzenberger, C., Gasharova, B.Rapid uplift of the Jwaneng kimberlite, south Botswana: caused by mantle metasomatism and documented by OH diffusion profiles in garnet from eclogitic xenoliths.Goldschmidt Conference 2008, Abstract p.A882.Africa, BotswanaDeposit - Jwaneng
DS200812-1098
2008
Gasharova, B.Sommer, H., Regenauerlieb, K., Gasharova, B., Siret, D.Grain boundaries: a possible water reservoir in the Earth's mantle?Mineralogy and Petrology, Vol. 94, 1-2, pp. 1-8.MantleWater
DS200812-1139
2008
Gasharova, B.Summer, H., RegenauerLieb, K., Gasharova, B., Siret, D.Grain boundaries: a possible water reservoir in the Earth's mantle?Mineralogy and Petrology, in press available, 8p.MantleWater
DS200912-0595
2009
Gasharova, B.Potgeiter, J., Sommer, H., Regenauer-Lieb, K., Gasharova, B., Purchase, M.OH and CO2 diffusion profiles in garnets from eclogite xenoliths from the Rovic diamond mine, South Africa. ( Unesco IGCP 557)Goldschmidt Conference 2009, p. A1046 Abstract.Africa, South AfricaDeposit - Rovic
DS200912-0596
2008
Gasharova, B.Potgeter, J., Sommer, H., Regenauer-Lieb, K., Gasharova, B.Oh and CO2 diffusion profiles in garnets from eclogitic xenoliths from the Victor mine, South Africa.American Geological Union, Fall meeting Dec. 15-19, Eos Trans. Vol. 89, no. 53, meeting supplement, 1p. abstractAfrica, South AfricaDeposit - Roberts Victor
DS200912-0603
2009
Gasharova, B.Purchase, M., Sommer, H., Regenauer-Lieb, K., Gasharova, B., Potgeiter, J.OH partitioning coefficient between garnets and melt inclusions in lherzolite xenoliths from the Kimberley diamond mine, South Africa.Goldschmidt Conference 2009, p. A1059 Abstract.Africa, South AfricaDeposit - Kimberley
DS201112-0816
2011
Gasharova, B.Potgeiter, J., Sommer, H., Regenauer-Lieb, K., Jung, H., Gasharova, B.The formation of microdiamonds in cracks caused by C-O-H rich fluid under medium to low pressure conditions.Goldschmidt Conference 2011, abstract p.1662.Africa, South AfricaVictor
DS201112-0836
2011
Gasharova, B.Purchase, M., Sommer, H., Regenauer-Lieb, K., Jung, H., Gasharova, B.Coexistent aqueous fluid phase and melt in lherzolites from Bultfontein, South Africa.Goldschmidt Conference 2011, abstract p.1675.Africa, South AfricaDeposit - Bultfontein
DS201112-0986
2011
Gasharova, B.Sommer, H., Regenauer-Lieb, K., Gaede, O., Jung, H., Gasharova, B.WEERTMAN cracks: a possible mechanism for near sonic speed diamond extraction from the Earth's mantle.Goldschmidt Conference 2011, abstract p.1908.MantleTransport for diamond bearing kimberlite melts
DS201212-0692
2012
Gasharova, B.Sommer, H., Regenauer-Lieb, K., Gasharova, B., Jung, H.The formation of volcanic centers at the Colorado Plateau as a result of the passage of aqueous fluid through the oceanic lithospher and the subcontinental mantle" new implications for the planetary water cycle in the western United States.Journal of Geodynamics, Vol. 61, Oct. pp. 154-171.United States, Colorado PlateauVolcanism
DS1986-0677
1986
Gaskarth, J.H.Rock, N.M.S., Gaskarth, J.H., Rundle, C.C.Late Caledonian dyke swarms in southern Scotland- a regional zone of primitive K rich lamprophyres abd associated ventsJournal of Geology, Vol. 94, No. 4, July pp. 505-522ScotlandDyke
DS1985-0404
1985
Gaskarth, J.W.Macdonald, R., Thorpe, R.S., Gaskarth, J.W., Grinrod, A.R.Multi-component Origin of Caledonian Lamprophyres of Northern England.Mineralogical Magazine., Vol. 49, No. 353 PT. 4 SEPTEMBER PP. 485-494.GlobalLamprophyres
DS1986-0053
1986
Gaskarth, J.W.Barnes, R.P., Rock, N.M.S., Gaskarth, J.W.Late Caledonian dike swarms in southern Scotland: new field.Petrological and geological dat a for the Wigtown Peninsula,GallowayGeol. Journal, Vol. 21, No. 2, April-June pp. 101-126ScotlandBlank
DS1988-0578
1988
Gaskarth, J.W.Rock, N.M.S., Gaskarth, J.W., Henney, P.J., Shand, P.Late Caledonian dyke swarms of northern Britain: some preliminary petrogeneic and tectonic implications of their province wide distribution andchemicCanadian Mineralogist, Vol. 26, No. 1, March pp. 3-22GlobalBlank
DS1995-1713
1995
Gaskarth, J.W.Shand, P., Gaskarth, J.W., Rock, N.M.S.Late Caledonian lamprophyre dyke swarms of south eastern ScotlandMineralogy and Petrology, Vol. 51, No. 2/4, pp. 277-298.ScotlandLamprophyres, Dikes
DS1996-0226
1996
Gaskarth, J.W.Canning, J.C., Morrison, M.A., Gaskarth, J.W.Geochemistry of late Caledonian minettes from northern Britain:implications for sub-continental lith. mantleMineralogical Magazine, Vol. 60, No. 1, Feb. 1, pp. 221-?ScotlandMinettes, Mantle lithosphere
DS1960-0453
1964
Gaskill, G.Gaskill, G.Harry Oppenheimer, South Africa's King of DiamondsReaders Digest., MAY, PP. 166-172.South AfricaBiography
DS2001-0134
2001
GasparBrod, 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
DS200712-0144
2007
GasparCarlson, R.W., Aruajo, Junqueira-Brod, Gaspar, Brod, Petrinovic, Hollanda, Pimentel, SichelChemical and isotopic relationships between peridotite xenoliths and mafic-ultrapotassic rocks from southern Brazil.Chemical Geology, Vol. 242, 3-4, pp. 418-437.South America, BrazilGeochemistry
DS200712-0145
2007
GasparCarlson, R.W., Aruajo, Junqueira-Brod, Gaspar, Brod, Petrinovic, Hollanda, Pimentel, SichelChemical and isotopic relationships between peridotite xenoliths and mafic-ultrapotassic rocks from southern Brazil.Chemical Geology, Vol. 242, 3-4, pp. 418-437.South America, BrazilGeochemistry
DS201112-0256
2011
GasparDe 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
DS1983-0541
1983
Gaspar, J.Roden, M.F., Murthy, V.R., Gaspar, J.Isotopic Composition of the Source for the Jacupiranga Carbonatite, Brasil.Geological Association of Canada (GAC), Vol. 15, No. 4, P. 257. (abstract.).BrazilRelated Rocks
DS1998-1319
1998
Gaspar, J.Sgarbi, P.B.A., Clayton, R.N., Mayeda, T.K., Gaspar, J.Oxygen isotope thermometry of Brazilian potassic volcanic rocks of kamafugitic affinities.Chemical Geology, Vol. 146, No. 3-4, May 5, pp. 115-126.BrazilGeochronology, Alkaline rocks
DS1998-1457
1998
Gaspar, J.Teixeira, N., Gaspar, J., Waissel, O., Almeida, A.Geology of the Juin a Diamondiferous province7th International Kimberlite Conference Abstract, pp. 905-7.BrazilMaars, Rio Negro Jurena Mobile Belt
DS1982-0302
1982
Gaspar, J.C.Jones, A.P., Gaspar, J.C., Wyllie, P.J.Pervoskites and Opaque Minerals in Carbonatites Associated with kimberlites in South Africa.Eos, Vol. 63, No. 45, P. 1134, (abstract.).South AfricaBlank
DS1983-0246
1983
Gaspar, J.C.Gaspar, J.C., Wylie, P.J.Ilmenite ( High Magnesium, Manganese, Niobium) in the Jacupiranga complex, Brasil.American Mineralogist., Vol. 68, No. 9-10, SEPT. Oct., PP. 960-971.BrazilRelated Rocks, Petrology
DS1983-0247
1983
Gaspar, J.C.Gaspar, J.C., Wyllie, P.J.Magnetite in the Carbonatites from the Jacupiringa Complex, brasil.American MINERALOGIST., Vol. 68, No. 1-2, PP. 195-213.BrazilMineralogy
DS1984-0294
1984
Gaspar, J.C.Gaspar, J.C., Wyllie, P.J.The Alleged Kimberlite-carbonatite Relationship: Evidence from Ilmenite and Spinel from Premier and Wesselton Mines and the Benfontein Sill, South Africa.Contributions to Mineralogy and Petrology, Vol. 85, No. 2, PP. 133-140.South AfricaGenesis, Related Rocks, Mineral Chemistry
DS1985-0566
1985
Gaspar, J.C.Roden, M.F., Murthy, R., Gaspar, J.C.Strontium and Neodymium Isotopic Composition of the Jacupiranga carbonatit E.Journal of GEOLOGY, Vol. 93, PP. 212-220.BrazilGeochronology, Isotope
DS1987-0240
1987
Gaspar, J.C.Gaspar, J.C., Wyllie, P.J.The phlogopites from the Jacupiranga carbonatite intrusionsMineralogy and Petrology, Vol. 36, No. 2, April, pp. 121-134BrazilGeochemistry, Analyses-mica
DS1991-0539
1991
Gaspar, J.C.Gaspar, J.C.The magmatic evolution of the Jacupiranga Complex, BrasilProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 127-129BrazilMagnetite pyroxenite, Carbonatite
DS1991-0975
1991
Gaspar, J.C.Leonardos, O.H., Meyer, H.O.A., Gaspar, J.C.Proceedings of Fifth International Kimberlite Conference GuidebookServico Geologico do Brasil (CPRM) Special Publication 3/91, Brasilia, 100pBrazilGuidebook, Diamond areas
DS1991-0976
1991
Gaspar, J.C.Leonardos, O.H., Ulbrich, M.N., Gaspar, J.C.The Mat a da Corda volcanic rocksFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 65-74BrazilGeology, Volcanics
DS1992-0517
1992
Gaspar, J.C.Gaspar, J.C.Titaniam clinohumite in the carbonatites of the Jacupiranga Complex, Brasil: mineral chemistry and comparison with titanian clinohumite fromenvironmentsAmerican Mineralogist, Vol. 77, No. 1-2, January-February pp. 168-178BrazilCarbonatite, Deposit -Jacupiranga
DS1994-0372
1994
Gaspar, J.C.Danni, J.C.M., Gaspar, J.C.Spinel garnet lherzolite and spinel lherzolite xenoliths from the northeastern border of Parana Basin.International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 14-16.BrazilXenoliths, Parana Basin
DS1994-0579
1994
Gaspar, J.C.Gaspar, J.C., Silva, A.J.C.C., Dearaujo, D.P.Composition of priderite in phlogopites from the Catalao I carbonatitecomplex, Brasil.Mineralogical Magazine, Vol. 58, No. 392, Sept. 409-415.BrazilCarbonatite
DS1994-0637
1994
Gaspar, J.C.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
DS1995-0592
1995
Gaspar, J.C.Gaspar, J.C., Araujo, D.P.Reaction products of carbonatite with ultramafic rocks in the Catalao Icomplex Brasil: possible implicationsProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 181-183.BrazilCarbonatite, Mantle Metasomatism
DS1995-0651
1995
Gaspar, J.C.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
DS1995-1708
1995
Gaspar, J.C.Sgarbi, P.B.A., Gaspar, J.C.Perovskites from the Mat a da Corda kamafugites, MG BrasilProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 498-499.Brazil, Minas GeraisKamafugites, alkaline, Deposit -Mata da Corda
DS1996-1415
1996
Gaspar, J.C.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
DS1998-0038
1998
Gaspar, J.C.Araujo, A.L.N., Gaspar, J.C., Bizzi, L.C.Petrography and mineralogy of kimberlites and kamafugites from the Alto Paranaiba Igneous Province..7th International Kimberlite Conference Abstract, pp. 26-28.Brazil, Minas GeraisSao Francisco Craton, Kimberlites, kamafugites, mafurites, ugandites
DS1998-0477
1998
Gaspar, J.C.Gaspar, J.C., Araujo, D.P., Melo, M.V.L.C.Olivine in carbonatitic and silicate rocks in carbonatite complexes7th International Kimberlite Conference Abstract, pp. 239-241.BrazilCarbonatite, Deposit - Catalao I, II
DS1998-0478
1998
Gaspar, J.C.Gaspar, J.C., Teixeira, N.A., Steele, I.M.Cathodluminescence of Juin a diamonds7th International Kimberlite Conference Abstract, pp. 242-4.BrazilAlluvials, Deposit - Juina
DS1998-0522
1998
Gaspar, J.C.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
DS1998-0599
1998
Gaspar, J.C.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
DS1998-1458
1998
Gaspar, J.C.Teixeira, N.A., Gaspar, J.C., Olivera, A., BitencourtMorphology of the Juin a Maars7th International Kimberlite Conference Abstract, pp. 902-4.BrazilPhreatomagmatic maars, Volcanic structures
DS2000-0285
2000
Gaspar, J.C.Fava, N., Gaspar, J.C.Pyrochlore varieties from the Catalao 1 carbonatite complex, BrasilIgc 30th. Brasil, Aug. abstract only 1p.BrazilCarbonatite, Deposit - Catalao-1
DS2000-0316
2000
Gaspar, J.C.Gaspar, J.C., Brod, J.A., Sgarbi, P.B.A., Brod, T.C.J.A review of the Cretaceous alkaline magmatism in western Minas Gerais and southern Goias.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Minas GeraisAlkaline rocks
DS2000-0883
2000
Gaspar, J.C.Sgarbi, P.B.A., Gaspar, J.C., Vaneca, J.G.Clinopyroxene from Brazilian kamafugitesLithos, Vol. 53, No. 2, Aug. pp. 101-16.BrazilKamafugites - Santo Antonia da Barra, Mata da Corda, Petrology
DS2001-0040
2001
Gaspar, J.C.Araujo, A.L.N., Carlson, R.W., Gaspar, J.C., Bizzi, L.Petrology of kamafugites and kimberlites from the Alto Paranaiba alkaline province, Minas Gerais, Brasil.Contributions to Mineralogy and Petrology, Vol. 142, No. 2, Nov. pp. 163-77.Brazil, Minas GeraisPetrology, Deposit - Alto Paranaiba region
DS2002-1444
2002
Gaspar, J.C.Sgarbi, P.B.de A., Gaspar, J.C.Geochemistry of Santo Antonio da Barra kamafugites, Goias, BrasilJournal of South American Earth Sciences, Vol.14, 8, March pp. 889-901.Brazil, GoiasGeochemistry
DS2003-0026
2003
Gaspar, J.C.Araujo, D.P., Gaspar, J.C., Fei, Y., Hauri, E.H., Hemley, R., Bulanova, G.P.Mineralogy of diamonds from the Juin a Province, Brazil8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractBrazilDiamonds
DS2003-0167
2003
Gaspar, J.C.Brod, J.A., Gaspar, J.C., Diniz-Pinto, H.S., Junqueira-Brod, T.C.Spinel chemistry as an indicator of crystal fractionation and liquid immiscibility in the8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractBrazil, Minas GeraisBlank
DS2003-0168
2003
Gaspar, J.C.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
DS2003-0288
2003
Gaspar, J.C.Costa, V.S., Gaspar, J.C., Pimentel, M.M.Peridotite and eclogite xenoliths from the Juin a kimberlite province, Brazil8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractBrazilBlank
DS2003-0444
2003
Gaspar, J.C.Gaspar, J.C., Araujo, A.L.N., Carlson, R.W., Sichel, S.E., Brod, J.A., SgarbiMantle xenoliths and new constraints on the origin of alkaline ultrapotassic rocks from8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractBrazilBlank
DS2003-0677
2003
Gaspar, J.C.Junqueira-Brod, T.C., Brod, J.A., Gaspar, J.C., Barbosa, E.S.R.Magma - sediments interaction in the Aguas Emendadas kamafugitic diatremes, GO8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractBrazil, GoiasKimberlite geology and economics, Deposit - Aguas Emendadas
DS2003-0678
2003
Gaspar, J.C.Junqueira-Brod, T.C., Gaspar, J.C., Brod, J.A., Barbosa, E.S.R.Magma mixing in Cretaceous kamafugites, Goias alkaline province, Brazil8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractBrazil, GoiasKimberlite geology and economics
DS200412-0213
2003
Gaspar, J.C.Brod, J.A., Gaspar, J.C., Diniz-Pinto, H.S., Junqueira-Brod, T.C.Spinel chemistry as an indicator of crystal fractionation and liquid immiscibility in the Tapira alkaline carbonatie complex, Mi8 IKC Program, Session 7, POSTER abstractSouth America, Brazil, Minas GeraisKimberlite petrogenesis
DS200412-0214
2003
Gaspar, J.C.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
DS200412-0375
2003
Gaspar, J.C.Costa, V.S., Gaspar, J.C., Pimentel, M.M.Peridotite and eclogite xenoliths from the Juin a kimberlite province, Brazil.8 IKC Program, Session 6, POSTER abstractSouth America, BrazilMantle petrology
DS200412-0612
2003
Gaspar, J.C.Gaspar, J.C., Araujo, A.L.N., Carlson, R.W., Sichel, S.E., Brod, J.A., Sgarbi, P.B., Danni, J.C.M.Mantle xenoliths and new constraints on the origin of alkaline ultrapotassic rocks from the Alto Paranaiba and Goias igneous pro8 IKC Program, Session 7, POSTER abstractSouth America, BrazilKimberlite petrogenesis
DS200412-1791
2004
Gaspar, J.C.Sgarbi, P.B., Heaman, L.M., Gaspar, J.C.U Pb perovskite for Brazialian kamafugitic rocks: further support for a temporal link to a mantle plume hotspot track.Journal of South American Earth Sciences, Vol. 16, 8, pp. 715-724.South America, Brazil, GoiasGeochemistry, geochronology, alkaline province
DS201212-0017
2012
Gaspar, J.C.Arajo, D.P., Bulanova, G.P., Walter, M.J., Kohn, S.C., Smith, C.B., Gaspar, J.C., WangJuina-5 kimberlite ( Brazil): a source of unique lower mantle diamonds.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractSouth America, BrazilDeposit - Juina-5
DS201212-0139
2012
Gaspar, J.C.Dalla-Costa, M.M., Santos, R.V., Araujo, D.P., Gaspar, J.C.Occurrence of garnets with eclogitic and lherzolitic compositions in garnet lherzolite xenolith from the Canastra-01 kimberlite pipe, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Canastra-01
DS201312-0024
2013
Gaspar, J.C.Arajuo, D.P., Gaspar, J.C., Bulanova, G.P.Juin a diamonds from kimberlites and alluvials: a omparison of morphology, spectral characteristics and carbon isotope composition.Proceedings of the 10th. International Kimberlite Conference, Vol. 1, Special Issue of the Journal of the Geological Society of India,, Vol. 1, pp. 255-269.South America, BrazilDeposit - Juina
DS201312-0100
2013
Gaspar, J.C.Brod, J.A., Junqueira-Brod, T.C., Gaspar, J.C., Petrinovic, I.A., De Castro Valente, S., Corval, A.Decoupling of paired elements, crossover REE patterns and mirrored spider diagrams: fingerprinting liquid immiscibility in the Tapira alkaline carbonatite complex, SE Brazil.Journal of South American Earth Sciences, Vol. 41, pp. 41-56.South America, BrazilTapira - mineral chemistry
DS200512-0492
2005
Gaspar, J-C.Junqueira-Brod, T.C., Gaspar, J-C., Brod, J.A., Jost, H., Rocha Barbosa, E.S., Kafino, C.V.Emplacement of kamafugitic lavas from the Goais alkaline province, Brazil: constraints from whole rock simulations. (mafurite, ugandite)Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 323-335.South America, BrazilSanto Antonio da Barra, Aguas Emendadas, carbonatite
DS200512-0493
2005
Gaspar, J-C.Junqueira-Brod, T.C., Gaspar, J-C., Brod, J.A., Kafino, C.V.Kamafugitic diatremes: their textures and field relationships with examples from the Goais alkaline province, Brazil.Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 337-353.South America, BrazilBreccia, lapilli, peperite, surge
DS200512-0902
2005
Gaspar, J-C.Ribeiro, C.C., Brod, J.A., Junqueira-Brod, T.C., Gaspar, J-C., Petrinovic, I.A.Mineralogical and field aspects of magma fragmentation deposits in a carbonate phosphate magma chamber: evidence from the Catalao I complex, Brazil.Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 355-369.South America, BrazilCarbonatite, Lagoa Seca, APIP, chamber pipes, surge
DS1998-0039
1998
Gaspar. J.C.Araujo, D.P., Gaspar. J.C., Garg, V.K.The complete phlogopite tetraferri phlogopite series in the Catalao I and II carbonatite complexes, Brasil.7th International Kimberlite Conference Abstract, pp. 29-31.Brazil, GoiasCarbonatite, Deposit - Catalao
DS2002-0505
2002
Gasparik, P.Gasparik, P., Litvin, Y.A.Experimental investigation of the effect of metasomatism by carbonatitic melt on the composition ..Lithos, Vol. 60, No. 3-4, Feb. pp. 129-43.MantleComposition and structure - deep
DS1989-0425
1989
Gasparik, T.Finger, L.W., Ko, J., Hazen, R.M., Gasparik, T., Hemley, R.J.Crystal chemistry of phase B and an anhydrous analogue:implications for water storage in the upper mantleNature, Vol. 341, No. 6238, Sept. 14, pp. 40-142GlobalMantle, Geochemistry
DS1990-0522
1990
Gasparik, T.Gasparik, T.The CMAS analogue of the earth mantleTerra, Abstracts of Experimental mineralogy, petrology and, Vol. 2, December abstracts p. 75GlobalMantle, CMAS system -xenoliths
DS1990-0523
1990
Gasparik, T.Gasparik, T.Evidence for the mineral and chemical layering in the earth upper mantleV.m. Goldschmidt Conference Held May 2-4, 1990, Program And Abstract, p. 49. Abstract onlyGlobalMantle, Geochemistry
DS1991-0708
1991
Gasparik, T.Herzberg, C., Gasparik, T.Garnet and pyroxenes in the mantle: a test of the majorite fractionationhypothesisJournal of Geophysical Research, Vol. 94, No. B 10, Sept. 10, pp. 16, 263-16, 274GlobalMantle, Experimental petrology
DS1993-0491
1993
Gasparik, T.Gasparik, T.The role of volatiles in the transition zoneJournal of Geophysical Research, Vol. 98, No. B3, March 10, pp. 4287-4299MantleGeochemistry, Subduction, Experimental petrology
DS1994-0580
1994
Gasparik, T.Gasparik, T.Mineral and chemical composition of the earth's upper mantleEos, Vol. 75, No. 16, April 19, p. 192-193.MantleMineralogy, Mineral chemistry
DS1994-0748
1994
Gasparik, T.Hazen, R.M., Gasparik, T.Crystal chemistry and high pressure behaviour of majorite type garnetsEos, Vol. 75, No. 16, April 19, p. 192.GlobalMineralogy, Mineral chemistry
DS1997-0372
1997
Gasparik, T.Gasparik, T.A model for the layered upper mantlePhysics of the Earth and Planetary Interiors, Vol. 100, No. 1-3, pp.MantleLayered
DS1998-0479
1998
Gasparik, T.Gasparik, T.New experimental constraints on the origin of majorite garnet inclusionsTerra Nova, Abstracts, Vol. 10, suppl. 1, 20. abstractMantleDiamond inclusions
DS2000-0317
2000
Gasparik, T.Gasparik, T.Evidence for the transition zone origin of some MgFeO inclusions in diamondEarth and Planetary Science Letters, Vol.183, No.1-2, Nov.30, pp. 1-5.MantleMagnesiowustite, perovskite, Transition zones, discontinuity
DS2000-0318
2000
Gasparik, T.Gasparik, T., Hutchison, M.T.Experimental evidence for the origin of two kinds of inclusions in diamonds from the deep mantle.Earth and Planetary Science Letters, Vol. 181, No. 1-2, Aug. 30, pp.103-14.MantleDiamond - inclusions, geochronology
DS2000-1001
2000
Gasparik, T.Wang, W., Gasparik, T.Evidence for a deep mantle origin of a NaPX-EN inclusion in diamondInternational Geology Review, Vol. 42, No. 11, Nov. pp. 1000-6.ChinaDiamond - inclusion
DS2000-1002
2000
Gasparik, T.Wang, W., Gasparik, T., Rapp, R.P.Partitioning of rare earth elements between CaSiO3 perovskite and co-existing phases: inclusions diamondsEarth and Planetary Science Letters, Vol.181, No.3, Sept.15, pp.291-300.GlobalDiamond - inclusions, genesis, Subduction
DS2000-1003
2000
Gasparik, T.Wang, W., Sueno, S., Gasparik, T.Enrichment processes at the base of the Archean lithosphere mantle: observations from trace element...Contributions to Mineralogy and Petrology, Vol. 139, No. 6, pp. 720-33.MantleDiamond - inclusions, Mineral chemistry - pyropic garnet
DS2002-0506
2002
Gasparik, T.Gasparik, T., Litvin, Y.A.Experimental investigation of the effect of metasomatism by carbonatic melt on the composition ...Lithos, Vol.60, pp. 129-43.MantleStructure - deep mantle, diamond inclusions, Carbonatite
DS2003-0445
2003
Gasparik, T.Gasparik, T.Phase diagrams for geoscientists. An atlas of the Earth's Interiors. Collection ofSpringer, 350p. $ 170. www.springer-ny.com/newspreviewsMantleBook - phase diagrams (evidence from majoritic garnet)
DS200412-0613
2003
Gasparik, T.Gasparik, T.Phase diagrams for geoscientists. An atlas of the Earth's Interiors. Collection of calculated diagrams.. whole upper mantle.Springer, 350p. $ 170.MantleBook - majorite
DS200412-1406
2003
Gasparik, T.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
DS1995-0411
1995
GasparonDellapasqua, F.N., Kamentsy, V.S., Gasparon, CrawfordAl-spinels in primitive arc volcanicsMineralogy Petrology, Vol. 53, No. 1-3, pp. 1-26.AustraliaMineralogy -spinels
DS1995-0593
1995
Gasparon, M.Gasparon, M., Collerson, K.D., et al.A new kimberlite field in the Archean of West GreenlandEos, Vol. 76, No. 46, Nov. 7. p.F643. Abstract.GreenlandKimberlites, Deposit -Nuuk area (south)
DS201504-0191
2015
Gasparon, M.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.
DS201609-1735
2016
Gasparon, M.Omarini, R.H., Gasparon, M., De Min, A.M., Comin-Chiaramonti, P.An overview of the Mesozoic-Cenozoic magmatism and tectonics of Eastern Paraguay and central Andes ( western Gondwana): implications for the composition of mantle sources.Journal of South American Earth Sciences, In press available, 19p.South America, ParaguayMagmatism
DS201611-2128
2016
Gasparon, M.Omarini, R.H., Gasparon, M., De Min, A., Comin-Chiaramonti, P.An overview of the Mesozoic-Cenozoic magmatism and tectonics in Eastern Paraguay and central Andes ( Western Gondwana): implications for the composition of mantle sources.Journal of South American Earth Sciences, Vol. 72, pp. 302-314.South America, ParaguayMagmatism

Abstract: The amalgamation of the Western Gondwana (including the Greater Gondwana supercraton) occurred at 600 Ma during the Brazilian - Pan African orogeny. A plate junction related to this event is marked by the Transbrazilian lineament which separates the South American continent into two sectors: the Eastern Paraguay-Brazilian and Central Andean domains. An overview of the geodynamic data from these two sectors indicates that the two domains were subjected to distinct evolutions from the Proterozoic to the present. The Andean domain is characterized by long-lived subduction processes linked to the convergence and consequent collision of microplates since the Middle Proterozoic (western Amazonian Craton) with a peak at about 600-580 Ma. The Paraguay-Brazilian domain remained relatively stable but was affected by extension episodes that reactivated ancient (Early and Middle Proterozoic) suture zones. These different geodynamic evolutions seem to reflect broadly distinct mantle compositions. In the subduction zones of the Andean domain the mantle was deeply modified by metasomatic processes following the subduction of oceanic plates. Consequently, the Andean type magma sources show a clear HIMU imprint inherited from the MORB, whereas the Paraguay-Brazilian sector shows a prevalent EMI and subordinate EMII character. The petrological data mainly from Mesozoic and Cenozoic magmatic events in the two sectors are reviewed to investigate the current mantle plume and mantle dome models for the uprising of the asthenospheric (or sub-lithospheric) material.
DS2002-0507
2002
Gasparth, T.Gasparth, T.Experimental investigation of the origin of majoritic garnet inclusions in diamondsPhysics and Chemistry of Minerals, Vol.29,3,pp.170-80., Vol.29,3,pp.170-80.GlobalPetrology, Diamond inclusions
DS2002-0508
2002
Gasparth, T.Gasparth, T.Experimental investigation of the origin of majoritic garnet inclusions in diamondsPhysics and Chemistry of Minerals, Vol.29,3,pp.170-80., Vol.29,3,pp.170-80.GlobalPetrology, Diamond inclusions
DS2003-0446
2003
Gasperini, D.Gasperini, D., Blichert Toft, J., Bosch, D., Del Moro, A., Macera, P., Albaraede, F.Upwelling of deep mantle material through a plate window: evidence from theJournal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001JB000418MantleGeophysics - seismics, Tectonics
DS200412-0614
2003
Gasperini, D.Gasperini, D., Blichert Toft, J., Bosch, D., Del Moro, A., Macera, P., Albaraede, F.Upwelling of deep mantle material through a plate window: evidence from the geochemistry of Italian basaltic volcanics.Journal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001 JB000418MantleGeophysics - seismics Tectonics
DS2003-0132
2003
Gasperini, L.Bonatti, E., Ligi, M., Brunelli, D., Cipriani, A., Fabretti, P., Ferrante, V., Gasperini, L.Mantle thermal pulses below the mid Atlantic Ridge and temporal variations in theNature, No. 6939, pp. 499-505.MantleGeothermometry
DS200412-0182
2003
Gasperini, L.Bonatti, E., Ligi, M., Brunelli, D., Cipriani, A., Fabretti, P., Ferrante, V., Gasperini, L., Ottolini, L.Mantle thermal pulses below the mid Atlantic Ridge and temporal variations in the formation of oceanic lithosphere.Nature, No. 6939, pp. 499-505.MantleGeothermometry
DS1993-0492
1993
Gasperini, M.Gasperini, M.Global forces on the lithosphereJournal of Geodynamics, Vol. 17, No. 3, July pp. 121-132.MantleTectonics
DS200412-0615
2004
Gasperini, P.Gasperini, P., DalForno, G., Boschi, E.Linear or non-linear rheology in the Earth's mantle: the prevalence of power law creep in the Post glacial isostatic readjustmentGeophysical Journal International, Vol. 157, 3, pp. 1297-1302.Mantle, LaurentiaTectonics, subduction
DS200512-0202
2005
Gasperini, P.Dal Forno, G., Gasperini, P., Boschi, E.Linear or nonlinear rheology in the mantle: a 3 D finite element approach to Post glacial rebound modeling.Journal of Geodynamics, Vol. 39, 2, pp. 183-195.MantleRheology, Laurentia, sea-level
DS200612-0430
2005
Gasquet, D.Gasquet, D., Levresse, G., Cheilletz, A., Azizi Samir, M.R., Mouttaqi, A.Contribution to a geodynamic reconstruction of the Anti-Atlas (Morocco) during Pan-African times with the emphasis on inversion tectonics and metallogeny...Precambrian Research, Vol. 140, 3-4, pp. 157-182.Africa, MoroccoTectonics - Precambrian-Cambrian transition
DS1970-0051
1970
Gass, I.G.Clifford, T.N., Gass, I.G.African Magmatism and TectonicsEdinburgh: Oliver And Boyd., South AfricaKimberlite, Kimberley, Janlib, Tectonics
DS1994-1076
1994
Gass, I.G.Macdonald, R., Williams, L.A., Gass, I.G.Tectonomagmatic evolution of Kenya rift valley -some geologicalperspectives.Journal of the Geological Society of London, Vol. 151, No. 5, Sept. pp. 879-888.KenyaTectonics, Rifting
DS201012-0036
2010
Gass, M.H.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
DS1991-0378
1991
Gass, O.G.Dewey, J.F., Gass, O.G., Curry, G.B., Harris, N.B.W., Sengor, A.M.C.Allochthonous terranesCambridge University Press, 150p. approx. $ 50.00GlobalTerranes, Book -ad
DS201112-1075
2011
Gassmuller, R.Van Hinsbergen, D.J.J., Steinberger, B., Doubrovine, P.V., Gassmuller, R.Acceleration and deceleration of India-Asia convergence since the Cretaceous: roles of mantle plumes and continental collision.Journal of Geophysical Research, in press availableIndia, China, AsiaHotspots
DS1960-0962
1968
Gast, P.W.Hills, F.A., Gast, P.W., Houston, R.S., Swainbank, I.G.Precambrian Geochronology of the Medicine Bow Mountains, Southeastern Wyoming #1Geological Society of America (GSA) Bulletin., Vol. 79, PP. 1757-1783.United States, Wyoming, Rocky Mountains, Medicine Bow MountainsBlank
DS1960-0963
1968
Gast, P.W.Hills, F.A., Gast, P.W., Houston, R.S., Swainbank, I.G.Precambrian Geochronology of the Medicine Bow Mountains, Southeastern Wyoming #2Wyoming Geological Survey Memoir., No. 1.United States, Wyoming, Rocky Mountains, Medicine Bow MountainsBlank
DS1975-0104
1975
Gast, P.W.Hills, F.A., Houston, R.S., Gast, P.W.Chronology of Some Precambrian Igneous and Metamorphic Events of the Medicine Bow Mountains, Wyoming.Geological Society of America (GSA) SPECIAL PAPER., No. 82, P. 92, (abstract.).United States, Wyoming, Rocky Mountains, Medicine Bow MountainsBlank
DS200612-0503
2006
Gastaldi, D.Groppo, C., Rinaudo, C.,Cairo, S., Gastaldi, D., Compagnoni, R.Micro-raman spectroscopy for a quick and reliable identification of serpentine minerals from ultramafics.European Journal of Mineralogy, Vol. 18, 3, May pp. 319-329.TechnologySpectroscopy - not specific to diamonds
DS1996-0489
1996
Gastaldo, R.A.Gastaldo, R.A., DiMichele, W.A., Pfefferkorn, H.W.Out of the Icehouse into the Greenhouse: a late Paleozoic analog for modern global vegetational changeGsa Today, Vol. 6, No. 10, October pp. 1-7GlobalStratigraphy, Global greenhouse
DS1970-0061
1970
Gate, N.H.Dawson, J.B., Gate, N.H.Uranium and Thorium in Alkalic Rocks from the Active Carbonatite Volcano Oldoniyo Lengai Tanzania.Chemical Geology, Vol. 6, No. 3, PP. 221-231.Tanzania, East AfricaGeology, Related Rocks
DS1990-0524
1990
Gates, A.E.Gates, A.E., Kambin, R.C.Comparison of the natural deformation of the State Line Sepentinite USA, with experimental studies.Tectonophysics, Vol. 182, pp. 249-58.AppalachiaLizardite
DS1991-0540
1991
Gates, A.E.Gates, A.E., Valentino, D.W.Late Proterozoic rift control on the shape of the Appalachians: the Pennsylvanian reentrantJournal of Geology, Vol. 99, pp. 863-872Midcontinent, AppalachiaTectonics, Proterozoic rift
DS1994-1821
1994
Gates, A.E.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
Gates, A.E.Glover, L., Gates, A.E.Central and southern Appalachians suturesGeological Society of America Special Paper, No. 314, $ 50.00Appalachia, MidcontinentBook - ad, Tectonics
DS1981-0175
1981
Gates, A.H.Gates, A.H., Sas, Z., Esterle, J., Carson, M., Pacific Exploration Co.El 477 Terowie South Australia Progress Reports from 16/8/79South Australia Open File., No. E3612, 104P. UNPUBL.Australia, South AustraliaGeochemistry, Prospecting, Stream Sediment Sampling, Rock Chip
DS1981-0361
1981
Gates, A.H.Sas, Z., Gates, A.H., Gem ex and min. ltd., CULTUS PACIFIC NL.El 504, El 505, Mt. Christie, Muckanippie, Lake Barry (tarcoSouth Australia Open File., No. E3596, E3597, E3598, 186P. UNPUBL.Australia, South AustraliaGeochemistry, Stream Sediment Sampling, Heavy Minerals
DS1981-0362
1981
Gates, A.H.Sas, Z., Gates, A.H., Gem ex and min. ltd., WESTERN QUEEN (SA).El 760 Canegrass and El 763 Nilpinna, South Australia, Progress and Final Reports.South Australia Open File., No. E4061, 22P. UNPUBL.Australia, South AustraliaLiterature Review, Diamonds, Stratigraphy, Artesian Basin
DS1920-0071
1921
Gates, H.L.Gates, H.L.The Mystery of the Hope DiamondNew York: International Copyright Bureau, 255P.IndiaDiamonds Notable, History
DS1981-0360
1981
Gates, T.Sas, Z., Esterle, J., Gates, T. , Western queen (sa) pty. ltd.El 779 Lobethal Sa, Progress Reports from 12/4/81 to September 1981.South Australia Open File., No. E4098, 44P. UNPUBL.Australia, South AustraliaGechemistry, Prospecting, Stream Sediment Sampling, Diamonds
DS1981-0363
1981
Gates, T.Sas, Z., Gates, T., Pacific exploration pty. ltd.El 493 Echunga District South Australia Progress Reports 15/9/79 to 15/9/81.South Australia Open File., No. E3563, 129P. UNPUBL.Australia, South AustraliaGeophysics, Geochemistry, Prospecting, Airborne Magnetics
DS1981-0176
1981
Gatifullina, D.S.Gatifullina, D.S., Khaydarov, A.A.Round Diamonds.)Doklady Academy of Sciences Nauk SSSR, UZBEKSKOY SSR., Vol. 1981, No. 1, PP. 26-28.RussiaKimberlite
DS2000-0319
2000
Gatinskii, Y.G.Gatinskii, Y.G., Vladova, G.L., Rozhkova, V.V.Seismicity and metallogeny of convergent plate boundaries in subduction zones.Doklady Academy of Sciences, Vol. 371a, No. 3, Mar-Apr. pp. 583-7.MantleGeophysics - seismics, Subduction
DS200412-0616
2004
Gatinsky, Y.G.Gatinsky, Y.G., Rundquist, D.V.Geodynamics of Eurasia: plate tectonics and block tectonics.Geotectonics, Vol. 38, 1, pp. 1-16.Europe, AsiaTectonics
DS202110-1615
2021
Gatta, G.D.Gatta, G.D., Hradil, K., Meven, M.Where is the hydrogen? ( neutron diffraction technology) Elements, Vol. 17, pp. 163-168.Mantlehydrogen

Abstract: How is hydrogen distributed among minerals and how is it bonded in their crystal structures? These are important questions, because the amount of hydrogen and the bonding configuration of hydrogen in crystalline materials governs many of that material’s properties: its thermal and compressional behavior, P-T phase stability, rheology, and electrical conductivity. A reliable reconstruction of the Earth’s interior, or the prediction of mineral transformations in complex industrial processes, must account for these parameters. Neutron diffraction can locate hydrogen sites in mineral structures, reveal any static or dynamic hydrogen disorder, help define the libration regime of hydrogen, and elucidate hydrogen-bonding configurations. Thus, that most elusive element for X-ray probes is perfectly detectable using neutrons.
DS201312-0724
2013
Gattacceca, J.Quesnel, Y., Gattacceca, J., Osinski, G.R., Rochette, P.Origin of the central magnetic anomaly at the Haughton impact structure, Canada.Earth and Planetary Science Letters, Vol. 368, pp. 116-122.CanadaImpacts
DS200512-0318
2005
Gatzmeier, A.Gatzmeier, A., Moorkamp, M.3D modelling of electrical anisotropy from electromagnetic array data: hypothesis testing for different upper mantle conduction mechanisms.Physics of the Earth and Planetary Interiors, Vol. 149, 3-4, April 15, pp. 225-242.MantleGeophysics - electromagnetic, EM
DS201412-0275
2014
Gaubas, E.Gaubas, E., Ceponis, T., Jasiunas, A., Kalendra, V., Pavlov, J., Kazuchits, N., Naumchik, E., Rusetsky, M.Lateral scan profiles of the recombination parameters correlated with distribution of grown-in impurities in HPHT diamond.Diamond and Related Materials, Vol. 47, pp. 15-26.TechnologySynthetics
DS1900-0187
1903
Gaubert, P.Gaubert, P.Sur Les Conditions de Formation et D'accroissement des Cristaux Naturels: Diamant.Paris Museum Nat. Hist. Bulletin., Vol. 91, PP. 428-430.GlobalSynthetic Diamond Manufacture
DS201012-0211
2010
Gaucher, C.Frimmel, H.E., Basei, M.S., Gaucher, C.Neoproterozoic geodynamic evolution of SW Gondwana: a southern African perspective.International Journal of Earth Sciences, In press available, 32p.Africa, South AfricaKalahari craton
DS201012-0218
2010
Gaucher, C.Gaucher, C., Frei, R., Chemale, F.Jr., Frei, D., Bossi, J., Martinez, G., Chiglino, L., Cernuschi, F.Mesoproterozoic evolution of the Rio de la Plat a Craton in Uruguay: at the heart of Rodinia?International Journal of Earth Sciences, In press available, 16p.South America, UruguayTectonics - not specific to diamonds
DS201112-0336
2011
Gaucher, C.Frimmel, H.E., Basei, M.S., Gaucher, C.Neoproterozoic geodynamic evolution of SW Gondwana: a southern African perspective.International Journal of Earth Sciences, Vol. 100, 2, pp. 323-354.Africa, South AfricaGeodynamics
DS201112-0347
2011
Gaucher, C.Gaucher, C., Frei, R., Chemale, F., Frei, D., Bossi, J., Martinez, G., Chiglino, L., Cernuschi, F.Mesoproterozoic evolution of the Rio de la Plat a craton in Uruguay: at the heart of Rodinia?International Journal of Earth Sciences, Vol. 100, 2, pp. 273-288.South America, UruguayCraton, Rodinia, Gondwana
DS202004-0544
2020
Gaucher, C.Will, T.M., Hohn, S., Frimmel, H.E., Gaucher, C., Le Roux, P.J., Macey, P.H.Petrological, geochemical and isotopic data of Neoproterozoic rock units from Uruguay and South Africa: correlation of basement terranes across the South Atlantic.Gondwana Research, Vol. 80, pp. 12-32.South America, Uruguay, Brazil, Africa, Namibiacraton

Abstract: Felsic to intermediate igneous rocks from the Cuchilla Dionisio (or Punta del Este) Terrane (CDT) in Uruguay and the Várzea do Capivarita Complex (VCC) in southern Brazil were emplaced in the Tonian and experienced high-grade metamorphism towards the end of the Cryogenian. Geological and geochemical data indicate an S-type origin and formation in a continental within-plate setting by recycling of lower crustal material that was initially extracted from the mantle in the Palaeoproterozoic. Similar felsic igneous rocks of Tonian age occur in the Richtersveld Igneous Complex and the Vredefontein and Rosh Pinah formations in westernmost South Africa and southern Namibia and have been correlated with their supposed equivalents in Uruguay and Brazil. Geochemical and isotope data of the largely unmetamorphosed felsic igneous rocks in southwestern Africa imply a within-plate origin and formation by partial melting or fractional crystallization of mafic rocks that were extracted from the mantle in the Proterozoic. The parental melts of all of these Tonian igneous rocks from South America and southwestern Africa formed in an anorogenic continental setting at the western margin of the Kalahari Craton and were emplaced in, and/or contaminated by, Namaqua Province-type basement after separation from their source region. However, the source regions and the time of extractions thereof are different and, moreover, occurred at different palaeogeographical latitudes. New petrological data of CDT high-grade gneiss indicate a geothermal gradient of c. 20-25 °C/km, implying continental collisional tectonics following subduction and ocean basin closure at an active continental margin at the eastern edge of present-day South America in the late Cryogenian to early Ediacaran. The associated suture may be traced by the high-grade gneiss and amphibolite-facies mafic rocks in the CDT and probably continues northwards to the Arroio Grande Complex and the VCC in southern Brazil.
DS202004-0513
2020
Gaucher, E.C.Gaucher, E.C.New perspectives in the industrial exploration for native hydrogen.Elements, Vol. pp. 8-9.Globalhydrogen

Abstract: Hydrogen gas (H2), when combusted, produces heat and water. There is no pollution, just water vapor. When hydrogen combines with oxygen, there is no generation of carbon dioxide, no production of cyclic hydro-carbons, no sulfur oxides (SOx), no nitrogen oxides (NOx), no ozone cogeneration. It seems that hydrogen, along with efficient energy production, solves many of our pollution problems, from urban air pollution to global warming. In the so-called Hydrogen Age of the future (Holland and Provenzano 2007), H2 will be mainly produced by the electrolysis of water using electricity that itself is derived from renewable energy sources or nuclear power plants. Steam methane reforming (a catalyzed reaction at high temperature where CH4 is combined with water to produce CO2 and H2) will only be acceptable as a source of H2 if it is associated with low-cost CO2 storage. But, in this future energy landscape, what is the role of naturally occurring hydrogen, sometimes referred to as native hydrogen?
DS202005-0732
2020
Gaucher, E.C.Gaucher, E.C.New perspectives in the industrial exploration for native hydrogen. ( brief review) whole issue on hydrogenElements, Vol. 18, 1, pp. 8-9.Globalhydrogen

Abstract: This article is a broad summary of the current state of knowledge concerning the potential exploration for native hydrogen across the globe. Native hydrogen has been identified in numerous source rocks in zones beyond sedimentary basins where petroleum companies typically operate. At the beginning of 2019 we may be at a tipping point with the first exploitable H2 field, potentially discovered in Mali. Of course, a number of issues and questions must still be resolved if these initial discoveries are to be transformed into a sustainable and abundant source of energy for society. However, the competencies that exist in the petroleum industry can readily be adapted by and to this new sector. New expertise will be needed to account for the reactivity of the hydrogen molecule in order to maximize exploration efforts and minimize the potential for chemical or biological consumption.
DS1960-0665
1966
Gaucher, E.H.Gaucher, E.H.Elsas-kapuskasing-moosonee Magnetic and Gravity HighsGeological Survey of Canada (GSC) PAPER., No. 66-1, PP. 189-191.Canada, Ontario, James Bay LowlandsStructure, Tectonics, Geophysics
DS1995-0594
1995
Gaudet, J.M.Gaudet, J.M., Roy, A.G.Effect of bed morphology on flow mixing length at river confluencesNature, Vol. 373, No. 6510, Jan. 12, p. 138-139.GlobalRivers, Sedimentology
DS201506-0263
2015
Gaudet, M.DeStefano, A., Shiroki, A., Zhuk, V., Gaudet, M.Detailed studies of Renard 2 kimberlite - some practical aspects.Vancouver Kimberlite Cluster, May 27, 1/4p. AbstractCanada, QuebecDeposit - Renard
DS201605-0839
2016
Gaudet, M.Gaudet, M.Renard 65: a multi phase pipe infilled with hypabyssal and Kimberley-type pyroclastic kimberlite.DCO Edmonton Diamond Workshop, June 8-10Canada, QuebecDeposit - Renard65
DS201609-1726
2016
Gaudet, M.Kopylova, M.G., Gaudet, M., Kostrovitsky, S.I., Polozov, A.G., Yakovlev, D.A.Origin of salts and alkali carbonates in the Udachnaya East kimberlite: insights from petrography of kimberlite phases and their carbonate and evaporite xenoliths.Journal of Volcanology and Geothermal Research, in press available 19p.RussiaDeposit - Udachnaya East

Abstract: The Udachnaya East kimberlite is characterized by the presence of chlorides, sulfates and alkali carbonates. This highly atypical mineralogy underpinned a model for an anhydrous alkali-rich primary kimberlite melt, despite the absence of petrographic studies providing textural context to the exotic minerals. The present work documents the petrography of the Udachnaya East kimberlite in order to address this problem. The pipe comprises two varieties of Fort-a-la-Corne type pyroclastic kimberlite, olivine-rich and magmaclast-rich, and coherent kimberlite. These kimberlites entrain xenoliths of limestones, altered shales and siltstones, halite-dominated rocks, dolomites, and coarse calcite rocks. The distinct varieties of the Udachnaya East kimberlite carry different populations of crustal xenoliths, which partially control the mineralogy of the host kimberlite. In magmaclast-rich pyroclastic kimberlite, where halite is absent from the crustal xenoliths, it is not observed in the interclast matrix, or within the magmaclasts. Halite occurs in the interclast matrix of olivine-rich pyroclastic kimberlite, where halite xenoliths are common. Large, ~ 30 cm halite xenoliths are uniquely restricted to the coherent kimberlite and show a strong reaction with it. The halite xenoliths are sourced from depths of ? 1500 to ? 630 m, where carbonate beds host multiple karst cavities filled with halite and gypsum and occasional sedimentary evaporites. The style of secondary mineralization at Udachnaya depends on whether the kimberlite is coherent or pyroclastic. Shortite, pirssonite and other alkali carbonates replacing calcite and possibly serpentine are abundant only in porous pyroclastic kimberlites of both types and in their shale/siltstone xenoliths. The lower porosity of the coherent kimberlite prevented the interaction of kimberlite with Na brines. Serpentinization localized around halite xenoliths started at temperatures above 500 °C, as indicated by its association with high-temperature iowaite. The model of the “dry” Na and Cl-rich primary kimberlite melt is invalidated on the basis of 1) the restriction of exotic salt minerals to certain kimberlite types and xenoliths; and 2) the absence of halite-rich melt inclusions in olivine of coherent kimberlite.
DS201703-0404
2017
Gaudet, M.Gaudet, M.The principal role of silicic crustal xenolith assimilation in the formation of Kimberley type pyroclastic kimberlites.Vancouver Kimberlite Cluster, Feb. 28, 1p. AbstractCanada, QuebecDeposit - Renard 65
DS201708-1647
2017
Gaudet, M.Gaudet, M.The principal role of silicic crustal xenolith assimilation in the formation of Kimberley-type pyroclastic kimberlites - a petrographic study of the Renard 65 kimberlite pipe, Quebec, Canada.11th. International Kimberlite Conference, OralCanada, QuebecDeposit - Renard 65

Abstract: The Renard 65 pipe is located in the Otish Mountains, Quebec, Canada. It is one of nine diamondiferous kimberlite pipes in the ~ 640 Ma Renard cluster and is the largest of four pipes in the Renard Mine reserve. Detailed characterizations of the petrographic and compositional features of these pipe-infilling kimberlite rock types supports their classification into three geological units: Kimb65a, Kimb65b, and Kimb65d. These pipe-infilling kimberlites are interpreted to represent the solidified products of two separate magmatic events: Phase A containing Kimb65a, and Phase B containing Kimb65b and Kimb65d. This research demonstrates that the interclast matrix modal mineralogy (diopside + phlogopite + serpentine) in pyroclastic rock types in the Renard 65 kimberlites are inconsistent with origins by hydrothermal alteration involving hydrous meteoric fluids. Detailed investigation of the reactions between granitic and gneissic crustal xenolith lithologies and their host kimberlites, suggests that reactions occur at both magmatic and subsolidus temperatures involving significant volumetric proportions of xenoliths. The assimilation of crustal xenoliths, and contamination of the kimberlite magmas primarily by Si, are demonstrated to result in enhanced degassing of magmatic volatiles during emplacement and stabilization of the hybrid groundmass assemblage diopside + phlogopite + serpentine over the non hybrid groundmass assemblage calcite + phlogopite + serpentine. It is thus interpreted that the spatial distribution of transitional to Kimberley-type pyroclastic kimberlite rock types, which are characterized by diopside-rich and calcite-poor matrix assemblages as observed in the Renard 65 pipe and other similar pipes, is a function of crustal xenolith distribution in the magma during emplacement. This model not only accounts for the features of Kimberley-type pyroclastic kimberlite rock types, but also the spatial distribution of these rock types in numerous pipes which is often not consistent with lateral textural gradations as has been previously proposed. These results further indicate that the different mineralogy and textures of Fort-à-la-Corne-type pyroclastic kimberlites with respect to Kimberley-type pyroclastic kimberlites may be a consequence of not only the structural controls imparted by the host rock lithology with implications for emplacement-related processes, but also the absence of contamination of the magma by silicic crustal xenoliths.
DS201708-1648
2017
Gaudet, M.Gaudet, M.Subsolidus compositional modification of kimberlitic spinel in the Renard 65 kimberlite pipe, Quebec, Canada - implications for the use of spinel chemistry in the identification of kimberlite phases.11th. International Kimberlite Conference, PosterCanada, Quebecdeposit - Renard 65
DS201808-1771
2018
Gaudet, M.Muntener, C., Gaudet, M.Geology of the Renard 2 pipe to 1000 depth, Renard mine, Quebec, Canada: insights into Kimberley type pyroclastic kimberlite emplacement.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0614-7 12p.Canada, Quebecdeposit - Renard

Abstract: The Renard 2 pipe is currently the deepest-drilled and most extensively studied kimberlite body in the Renard cluster, central Québec, Canada, forming the major component of the Mineral Resource of Stornoway Diamond Corporation’s Renard Mine. Renard 2 is infilled with two distinct kimberlite units that exhibit Kimberley-type pyroclastic kimberlite and related textures. Hypabyssal kimberlite also occurs as smaller cross-cutting sheets and irregular intrusions. The units are distinguished by their rock textures, groundmass mineral assemblages, olivine macrocryst size distributions and replacement products, mantle and country rock xenolith contents, whole rock geochemical signatures, bulk densities and diamond grades. These differences are interpreted to reflect different mantle ascent and near-surface emplacement processes and are here demonstrated to be vertically continuous from present surface to over 1000 m depth. The distinctive petrological features together with sharp, steep and cross-cutting internal contact relationships, show that each unit was formed from a separate batch of mantle-derived kimberlite magma, and was completely solidified before subsequent emplacement of the later unit. The mineralogy and textures of the ultra-fine-grained interclast matrix are consistent with those described at numerous Kimberley-type pyroclastic kimberlite localities around the world and are interpreted to reflect rapid primary crystallization during emplacement of separate kimberlite magmatic systems. The units of fractured and brecciated country rock surrounding the main kimberlite pipe contain kimberlite-derived material including carbonate providing evidence of subsurface brecciation. Together these data show that Renard 2 represents the deeper parts of a Kimberley-type pyroclastic kimberlite pipe system and demonstrates that their diagnostic features result from magmatic crystallisation during subsurface volcanic emplacement processes.
DS201810-2319
2018
Gaudet, M.Gaudet, M., Kopylova, M., Muntener, C., Zhuk, V., Nathwani, C.Geology of the Renard 65 kimberlite pipe, Quebec, Canada.Mineralogy and Petrology, doi.org/10.1007/ s00710-018-0633-4 13p.Canada, Quebecdeposit - Renard

Abstract: Renard 65, a diamondiferous pipe in the Neoproterozoic Renard kimberlite cluster (Québec, Canada), is a steeply-dipping and downward-tapering diatreme comprised of three pipe-filling units: kimb65a, kimb65b, and kimb65d. The pipe is surrounded by a marginal and variably-brecciated country rock aureole and is crosscut by numerous hypabyssal dykes: kimb65c. Extensive petrographic and mineralogical characterization of over 700 m of drill core from four separate drill holes, suggests that Renard 65 is a Group I kimberlite, mineralogically classified as phlogopite kimberlite and serpentine-phlogopite kimberlite. Kimb65a is a massive volcaniclastic kimberlite dominated by lithic clasts, magmaclasts, and discrete olivine macrocrysts, hosted within a fine-grained diopside and serpentine-rich matrix. Kimb65b is massive, macrocrystic, coherent kimberlite with a groundmass assemblage of phlogopite, spinel, perovskite, apatite, calcite, serpentine and rare monticellite. Kimb65c is a massive, macrocrystic, hypabyssal kimberlite with a groundmass assemblage of phlogopite, serpentine, calcite, perovskite, spinel, and apatite. Kimb65d is massive volcaniclastic kimberlite with localized textures that are intermediate between volcaniclastic and coherent, with tightly packed magmaclasts separated by a diopside- and serpentine-rich matrix. Lithic clasts of granite-gneiss in kimb65a are weakly reacted, with partial melting of feldspars and crystallization of richterite and actinolite. Lithic clasts in kimb65b and kimb65d are entirely recrystallized to calcite + serpentine/chlorite + pectolite and display inner coronas of diopside-aegirine and an outer corona of phlogopite. Compositions are reported for all minerals in the groundmass of coherent kimberlites, magmaclasts, interclast matrices, and reacted lithic clasts. The Renard 65 rocks are texturally classified as Kimberley-type pyroclastic kimberlites and display transitional textures. The kimberlite units are interpreted to have formed in three melt batches based on their distinct spinel chemistry: kimb65a, kimb65b and kimb65d. We note a strong correlation between the modal abundances of lithic clasts and the textures of the kimberlites, where increasing modal abundances of granite/gneiss are observed in kimberlites with increasingly fragmental textures.
DS201902-0286
2018
Gaudet, M.Kopylova, M.G., Fulop, A., Gaudet, M., Hilchie, L.Kimberlite skarns: more common and more complex.Goldschmidt Conference, 1p. AbstractMantlepetrology

Abstract: When carbonate-rich and silicate rocks are juxtaposed at high subsolidus temperature, their contrasting elemental chemical potentials trigger metasomatism. Kimberlites in contact with felsic-to-mafic rocks should theoretically develop skarn alteration, replacing both the wall rocks and magmatic rocks. Although some kimberlites are well exposed from mining, metasomatic effects in them are difficult to isolate because of the common presence of marginal country rock breccias and assimilated country rock xenoliths. The volatilerich nature of kimberlite melts and faulting prior to the emplacement results in country rock brecciation and incorporation of as much as 70% xenoliths in kimberlite. We discuss several examples of mineralogical, textural and chemical zonation at contacts between felsic-to-mafic xenoliths, in-situ country rocks and kimberlites (Renard, Gahcho Kue, Snap Lake and Orapa). The subsolidus skarn reactions are preceded by magmatic assimilation. It partially melts feldspars and forms diopside and phlogopite coronas on xenoliths. To distinguish between incorporation and assimilation of xenoliths and contact metasomatism, we employed an improved isocon analysis that enables estimation of metasomatic contributions to geochemical diversity. Skarn reactions replace the original kimberlite minerals with serpentine, phlogopite, hydrogarnet, while xenoliths are replaced by serpentine, clinopyroxene, carbonate, chlorite, and pectolite. If the mode of felsic-to-mafic xenoliths exceeds 30%, the textures and the mineralogy of the kimberlite altered by assimilation and skarn reactions may resemble those of the Kimberly-type pyroclastic kimberlite (KPK). The distinct mineralogy of the KPK interclast matrix, the correlation between xenolith modes and the kimberlite texture, the spatial distribution of KPK in Renard and Gahcho Kue kimberlites indicate the principal role of crustal xenoliths in the KPK formation. Our data suggest that metasomatic recrystallization of kimberlites is more widespread than previously recognized, but is complex and accompanied by xenolith assimilation.
DS202204-0530
2022
Gaudet, M.Niyazova, S., Kopylova, M., Gaudet, M.Petrographic and geochemical characteristics associated with felsic xenolith assimilation in kimberlite.The Canadian Mineralogist, Vol. 60, pp. 1-25. pdfCanada, Quebecdeposit - Renard

Abstract: Assimilation of country rock xenoliths by the host kimberlite can result in the development of concentric reaction zones within the xenoliths and a reaction halo in the surrounding contaminated kimberlite. Petrographic and geochemical changes across the reaction zones in the xenoliths and the host kimberlite were studied using samples with different kimberlite textures and contrasting xenolith abundances from the Renard 65 kimberlite pipe. The pipe, infilled by Kimberley-type pyroclastic (KPK) and hypabyssal kimberlite (HK) and kimberlite with transitional textures, was emplaced into granitoid and gneisses of the Superior Craton. Using samples of zoned, medium-sized xenoliths of both types, mineralogical and geochemical data were collected across xenolith-to-kimberlite profiles and contrasted with those of fresh unreacted country rock and hypabyssal kimberlite. The original mineralogy of the unreacted xenoliths (potassium feldspar-plagioclase-quartz-biotite in granitoid and plagioclase-quartz-biotite-orthopyroxene in gneiss) is replaced by prehnite, pectolite, and diopside. In the kimberlite halo, olivine is completely serpentinized and diopside and late phlogopite crystallized in the groundmass. The xenoliths show the progressive degrees of reaction, textural modification, and mineral replacement in the sequence of kimberlite units KPK — transitional KPK — transitional HK. The higher degree of reaction observed in the HK-hosted xenoliths as compared to the KPK-hosted xenoliths in this study and elsewhere may partly relate to higher temperatures in xenoliths included in an HK melt. The correlation between the degree of reaction and the kimberlite textures suggests that the reactions are specific to and occur within each emplaced batch of magma and cannot result from external post-emplacement processes that should obliterate the textural differences across the kimberlite units. Xenolith assimilation may have started in the melt, as suggested by the textures in the xenoliths and the surrounding halos and proceeded in the subsolidus. Elevated CaO at the kimberlite-xenolith contact appears to be an important factor in producing the concentric mineralogical zoning in assimilated xenoliths.
DS202205-0709
2022
Gaudet, M.Niayzova, S., Kopylova, M., Gaudet, M., de Stefano, A.Petrographic and geochemical characteristics associated with felsic xenolith assimilation in kimberlite.Canadian Mineralogist, Vol. 60, 2, pp. 283-307.Canada, Quebecdeposit - Renard

Abstract: Assimilation of country rock xenoliths by the host kimberlite can result in the development of concentric reaction zones within the xenoliths and a reaction halo in the surrounding contaminated kimberlite. Petrographic and geochemical changes across the reaction zones in the xenoliths and the host kimberlite were studied using samples with different kimberlite textures and contrasting xenolith abundances from the Renard 65 kimberlite pipe. The pipe, infilled by Kimberley-type pyroclastic (KPK) and hypabyssal kimberlite (HK) and kimberlite with transitional textures, was emplaced into granitoid and gneisses of the Superior Craton. Using samples of zoned, medium-sized xenoliths of both types, mineralogical and geochemical data were collected across xenolith-to-kimberlite profiles and contrasted with those of fresh unreacted country rock and hypabyssal kimberlite. The original mineralogy of the unreacted xenoliths (potassium feldspar-plagioclase-quartz-biotite in granitoid and plagioclase-quartz-biotite-orthopyroxene in gneiss) is replaced by prehnite, pectolite, and diopside. In the kimberlite halo, olivine is completely serpentinized and diopside and late phlogopite crystallized in the groundmass. The xenoliths show the progressive degrees of reaction, textural modification, and mineral replacement in the sequence of kimberlite units KPK — transitional KPK — transitional HK. The higher degree of reaction observed in the HK-hosted xenoliths as compared to the KPK-hosted xenoliths in this study and elsewhere may partly relate to higher temperatures in xenoliths included in an HK melt. The correlation between the degree of reaction and the kimberlite textures suggests that the reactions are specific to and occur within each emplaced batch of magma and cannot result from external post-emplacement processes that should obliterate the textural differences across the kimberlite units. Xenolith assimilation may have started in the melt, as suggested by the textures in the xenoliths and the surrounding halos and proceeded in the subsolidus. Elevated CaO at the kimberlite-xenolith contact appears to be an important factor in producing the concentric mineralogical zoning in assimilated xenoliths.
DS1975-0111
1975
Gaudette, H.E.Hurley, P.M., Fairbairn, H.W., Gaudette, H.E.Progress Report on Early Archean Rocks in Liberia, Sierra Leone and Guyana and Their General Stratigraphic Setting.In: The Early History of The Earth, Windley, B.f. Editor, Jo, PP. 511-524. 619P.Sierra Leone, Liberia, Guiana, West Africa, South AmericaGeology
DS1985-0219
1985
Gaudette, H.E.Gaudette, H.E., Olszewski, W.J.Geochronology of the basement rocks, Amazonas Territory, Venezuela and the tectonic evolution of western Guiana Shield.Geologie et Mijnbouw., Vol. 64, pp. 131-43.Venezuela, GuyanaGeochronology, Tectonics
DS1996-0490
1996
Gaudette, H.E.Gaudette, H.E., Olezewski, W.J., Santos, J.Geochronology of Precambrian rocks from the northern part of the GuianaShield, State of RoraimaJournal of South American Earth Sciences, Vol. 9, No. 3/4, pp. 183-196BrazilGeochronology, Guiana Shield
DS2000-0350
2000
Gaudette, H.E.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
DS1994-0581
1994
Gaudreau, D.Gaudreau, D.District miniere de Cote Nord Nouveau Quebec. #1Quebec Department of Mines, DV 94-01, pp. 147-74.Quebec, Ungava, LabradorGeology
DS1995-0595
1995
Gaudreau, D.Gaudreau, D., Perreault, S.District miniere de Cote Nord Nouveau Quebec. #2Quebec Department of Mines, DV 95-01, pp. 141-65.Quebec, Ungava, LabradorGeology
DS1997-0373
1997
Gaudreau, D.Gaudreau, D.Field work report, Abloviak Fjord property, PEM 1197, Eastern Ungava Bay, Quebec.Quebec Department of Mines, GM 55257, 49p.Quebec, Ungava, LabradorExploration - assessment
DS1997-0260
1997
Gauert, C.D.K.De Waal, S.A., Gauert, C.D.K.The Basal Gabbro Unit and the identity of the parental magma of the Uitkomst Complex, Badplaas, South Africa.South African Journal of Geology, Vol. 100, 4, Dec. pp. 349-361.South AfricaLayered intrusion, Harzburgite
DS201707-1326
2017
Gauert, C.D.K.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.
DS201812-2810
2019
Gauert, C.D.K.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.
DS201909-2041
2019
Gauert, C.D.K.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.
DS201902-0273
2019
Gauert, C.K.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.
DS1998-0538
1998
GaulGriffin, W.L., O'Reilly, S.Y., Ryan, C.G., Gaul, IonovSecular variation in the composition of lithospheric mantle: geophysical and geodynamic implications.Structure EVol. Austral., American Geophysical Union (AGU) geodynamics Vol. 26, pp. 1-26.MantleGeophysics, geodynamics
DS1998-0480
1998
Gaul, O.Gaul, O., O'Reilly, S.Y., Griffin, W.L.Lithosphere mapping in eastern Australia7th International Kimberlite Conference Abstract, pp. 245-7.AustraliaTectonics, Geothermometry
DS201112-0348
2000
Gaul, O.Gaul, O.Composition of the lower continental crust beneath the Cheyenne Belt S. Wyoming, N. Colorado...geochemicalThesis: Macquarie University Phd. , AustraliaThesis: note availability based on request to author
DS2000-0320
2000
Gaul, O.F.Gaul, O.F., Griffin, W.L., Pearson, N.J.Mapping olivine composition in the lithospheric mantleEarth and Planetary Science Letters, Vol. 182, No. 3-4, Nov. 15, pp. 223-35.MantleOlivine
DS200412-0617
2004
Gaul, O.F.Gaul, O.F., O'Reilly, S.Y., Griffin, W.L.Lithosphere structure and evolution in southeastern Australia.Hillis, R.R., Muller, R.D. Evolution and dynamics of the Australian Plate, Geological Society America Memoir, No. 372, pp. 185-202.AustraliaTectonics
DS1989-0476
1989
Gault, C.D.Gault, C.D.Exploration preview northwest Territories -1989northwest Territories Geology Division, March 1989, 16p. Database # 17672Northwest TerritoriesExploration, Overview - Companies and projects
DS2002-1253
2002
Gault, R.Petersen, O.V., Niedermayr, G., Johnson, O., Gault, R.Lovdarite from the Ilmaussaq alkaline complex, South GreenlandNeues Jahrbuch Mineralogy Monatsche, Vol.14, 1, pp. 23-30.GreenlandAlkaline - mineralogy
DS1990-0721
1990
Gault, R.A.Horvath, L., Gault, R.A.The mineralogy of Mont Saint Hilaire QuebecMineralogical Record, Vol. 24, July-August pp. 284-268QuebecAlkaline rocks, Mineralogy -Photographs
DS2001-0910
2001
Gault, R.A.Petersen, O.V., Gault, R.A., Balic-Zunic, T.Odintsovite from the Ilimaussaq alkaline complex, South GreenlandNeues Jahrbuch f?r Mineralogie Mh., No. 5, pp. 235-40.GreenlandAlkaline rocks, Ilmaussaq Complex
DS200412-1535
2004
Gault, R.A.Petersen, O.V., Johnsen, O., Gault, R.A., Niedermayr, G., Grice, J.D.Taseqite, a new member of the eudialyte group from the Ilmassaq alkaline complex.Neues Jahrbuch fur Mineralogie - Monatshefte, No. 2, Feb. 1, pp. 83-96.Europe, GreenlandMineralogy
DS202011-2043
2019
Gault, R.A.Horvath, L., Gault, R.A., Pfenninger-Horvath, Poirier, G.Mont Saint-Hilaire: history, geology, mineralogy.The Canadian Mineralogist, Special Publication 14, 634p. Canada, QuebecBook

Abstract: This paper introduces a special section of the Canadian Journal of Development Studies, "The Africa Mining Vision: A Manifesto for More Inclusive Extractive Industry-Led Development?" Conceived by African ministers "in charge of mineral resources" with inputs and guidance from African Union Heads of State, the Africa Mining Vision (AMV) was officially launched in February 2009. The papers presented in this special section reflect critically on progress that has since been made with operationalising the AMV at the country level across Africa; the general shortcomings of the manifesto; and the challenges that must be overcome if the continent is to derive g Taking over 20 years of meticulous preparation, László and Elsa Horváth, a duo of dedicated and dynamic amateur mineralogists, along with two researchers, Robert Gault, a mineralogist, and Glenn Poirier, a geologist, have produced the ultimate book "Mont Saint-Hilaire: History, Geology, Mineralogy". The photography captures the colors of Vásárely, the symmetry of Escher, the form of Bartók and the intricate patterns of Mandelbrot, all found here, in this miracle of nature. One cannot but marvel at how this single, small quarry contains such mineral diversity. At last count, over 434 mineral species have been found at Mont Saint-Hilaire, representing 9% of all known mineral species. The 66 type minerals first described from this locality represent 1.3 % of all mineral species, placing the Poudrette quarry in an extremely rarified class for worldwide mineral localities. Almost half, 47, of all known chemical elements are included in this mineral mix. Beginning some 124 million years ago, several million years and a variety of geological processes were needed to accomplish this assemblage. Be captivated, learn and, most of all, enjoy!reater economic benefit from its abundant mineral wealth.
DS1997-0374
1997
Gaulton, R.Gaulton, R.Minerals - old industry, new realitiesAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 5, Aug, pp. 44-48AustraliaEconomics, ore reserves, geostatistics, Legal, reporting
DS2002-0405
2002
GaumetDromart, G., Garcia, J.P., Allemand, Gaumet, RouselleA volume based approach to calculation of ancient carbonate accumulationsJournal of Geology, Vol.110,1,pp. 195-210.GlobalCarbonate - overview deposit rates, Phanerozoic - exogenic systems
DS200412-1640
2004
Gaunt, F.Read, G., Grutter, H., Winter, S., Luckman, N., Gaunt, F., Thomsen, F.Stratigraphic relations, kimberlite emplacement and lithospheric thermal evolution Quirico Basin, Minas Gerais State, Brazil.Lithos, Vol. 77, 1-4, Sept. pp. 803-818.South America, Brazil, Minas GeraisAreado, clinopyroxene, kamafugite, Mata da Corda, therm
DS1988-0522
1988
Gaunt, G.F.M.Ollier, C.D., Gaunt, G.F.M., Jurkowski, I.The Kimberley Plateau, Western Australia: a Precambrian erosionSOURCE[ Zeitschrift fur GeomorphologieZeitschrift fur Geomorphologie, Vol. 32, No. 2, June pp. 239-246AustraliaTectonics, Kimberley Plateau
DS2003-1143
2003
Gaunt, G.F.M.Read, G.H., Grutter, H.S., Winter, L.D.S., Luckman, N.B., Gaunt, G.F.M.Stratigraphic relations, kimberlite emplacement and lithospheric thermal evolution8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, AbstractBrazil, Minas GeraisDiamond exploration - thermometry, pipe emplacement
DS200412-1641
2003
Gaunt, G.F.M.Read, G.H., Grutter, H.S., Winter, L.D.S., Luckman, N.B., Gaunt, G.F.M.Stratigraphic relations, kimberlite emplacement and lithospheric thermal evolution, Quirico Basin, Minas Gerais State, Brazil.8 IKC Program, Session 8, AbstractSouth America, Brazil, Minas GeraisDiamond exploration - thermometry, pipe emplacement
DS1989-1442
1989
Gaur, V.K.Sringesh, D., Rai, S.S., Ramesh, D.S., Gaur, V.K., Rao, C.V.R.Evidence for thick continental roots beneath South Indian shieldGeophysical Research Letters, Vol. 16, No. 9, September pp. 1055-1058IndiaMantle
DS1991-0629
1991
Gaur, V.K.Gupta, A.K., Gaur, V.K., Zharikov, V.A., Chudenovshikh, L.T.Proceedings of the second Ind-Soviet Workshop on Experimental mineralogy and petrology. Short book reviewGovernment of India, Department of Science and Technology, 164p. do not have -perhaps can obtainIndiaExperimental petrology, Conference held October 1989
DS200412-0750
2003
Gaur, V.K.Gupta, S., Rai, S.S., Prakasam, K.S., Srinagesh, D., Basal, B.K., Chadha, R.K., Priestly, K., Gaur, V.K.The nature of the crust in southern India: implications for Precambrian crustal evolution.Geophysical Research Letters, Vol. 30, 8, 10.1029/2002 GLO16770IndiaTectonics
DS200412-0751
2003
Gaur, V.K.Gupta, S., Rai, S.S., Prakasam, K.S., Sringesh, D., Chadha, R.K., Priestly, K., Gaur, V.K.First evidence for anomalous thick crust beneath mid Archean western Dharwar craton.Current Science, Vol. 84, 9, pp. 1219-26.IndiaCraton
DS200912-0292
2009
Gaur, V.K.Heintz, M., Kumar, V.P., Gaur, V.K., Priestly, K., Rai, S.S., Prakasam, K.S.Anisotropy of the Indian continental lithospheric mantle.Geophysical Journal International, Vol. 179, 3, pp. 1341-1360.IndiaGeodynamics
DS200912-0609
2009
Gaur, V.K.Rai, A., Gaur, V.K., Rai, S.S., Preistley, K.Seismic signatures of the Pan-African orogeny: implications for southern Indian high grade terranes.Geophysical Journal International, Vol. 176, 2, pp. 518-528.IndiaUHP
DS202108-1277
2021
Gaurine, F.Derycke, A., Gautheron, C., Barbarand, J., Bourbon, P., Aertgeerts, G., Simon-Labric, T., Sarda, P., Pinna-Jamme, R., Boukari, C., Gaurine, F.French Guiana margin evolution: from Gondwana break-up to Atlantic Ocean.Terra Nova, Vol. 33, 4, pp. 415-422. pdfSouth America, French GuianaGuiana Shield

Abstract: Knowledge of the Guiana Shield evolution during the Gondwana break-up is key to a better understanding of craton dynamics and margin response to transtensional opening. To improve this knowledge, we investigated the dynamics and thermal evolution of French Guiana, using several low-temperature thermochronology methods applied to basement rocks, including apatite and zircon (U-Th)/He and apatite fission tracks. Inverse modelling of results allows us to reconstruct the Phanerozoic thermal history of French Guiana margin and to give a preview of the Guiana Shield evolution. Three main events are inferred: firstly, a long-term period of relative stability since ~1.2 Ga, with no strong evidence for any erosional or burial event (>5-7 km); secondly, a heating phase between ~210 and ~140 Ma consistent with the Central Atlantic Magmatic Province-related event. Finally, an exhumation phase between ~140 and ~90 Ma, triggered by the Equatorial Atlantic opening, brought samples close to the surface (<40°C).
DS200712-1030
2007
Gautam, G.C.Srivastava, R.K., Gautam, G.C.Geochemistry of distinct mafic intrusive rocks from Darba-Kukanar and Kerlapal-Sukma-Mokhp southern Bastar Craton: further dat a on the Early Precambrian mafic magmatism of central India.Journal of the Geological Society of India, Vol. 69, 6, pp. 1176-1188.IndiaBastar Craton
DS200912-0726
2009
Gautam, G.C.Srivastava, R.K., Gautam, G.C.Precambrian mafic magmatism in the Bastar Craton - central India.Journal of the Geological Society of India, Vol. 73, 1, pp. 52-72.IndiaMagmatism
DS201012-0746
2010
Gautam, G.C.Srivastava, R.K., Gautam, G.C.Map of distinct early Precambrian mafic dyke swarms from the central Indian Bastar Craton and their possible relation with Paleosupercontinent and Large Igneous Province.International Dyke Conference Held Feb. 6, India, 1p. AbstractIndiaBastar Craton geochronology
DS201012-0747
2010
Gautam, G.C.Srivastava, R.K., Mondal, S.K., Balaram, V., Gautam, G.C.PGE geochemistry of low Ti high Mg siliceous mafic rocks within the Archean Central Indian Bastar Craton: implications for magma fractionation.Mineralogy and Petrology, Vol. 98, 1-4, pp. 329-345.IndiaMagmatism - not specific to diamonds
DS201509-0430
2015
Gautam, G.C.Srivastava, R.K., Gautam, G.C.Geochemistry and petrogenesis of Paleo-Mesoproterozoic mafic dyke swarms from northern Bastar craton, central India: geodynamic implications in reference to Columbia supercontinent.Gondwana Research, Vol. 28, pp. 1061-1078.IndiaDike swarms

Abstract: Field setting, petrography, geochemistry and available radiometric ages of Proterozoic mafic dykes from the northern Bastar craton have helped to identify four sets of mafic dykes; two Paleoproterozoic [viz. NW-SE North Bastar dykes (NBD) and ENE-WSW Dongargarh-Chhura dykes (DCD)] and two Mesoproterozoic [viz. 1.42 Ga ENE-WSW Bandalimal dykes (BDD) and 1.44 Ga N-S Lakhna dykes (LKD)]. Their petrographic and geochemical characteristics are very distinct and suggest their derivation from different mantle melts. Chemistry of all the four sets suggests different petrogenetic histories and samples of each distinct set are co-genetic nature. The NBD, the DCD and the BDD samples are sub-alkaline tholeiitic in nature, whereas the LKD samples show alkaline nature. Very distinct REE patterns are observed for all the four sets again suggesting their different petrogenetic histories. Geochemical comparison between the studied samples and mafic dyke samples of southern and central parts of the Bastar craton suggests very different picture for the northern Bastar craton. Only one set of northern Bastar dykes, i.e. the NBD, matches with BD1 dykes; no other dyke sets match with any of the dyke swarms identified in southern and central Bastar craton. Geochemically it is not straightforward to confirm crustal contamination, however, on the other hand, possibility of crustal contamination cannot be ruled out completely. A petrogenetic model based on trace element data suggests that all the four sets are derived from different mantle melts. The NBD and the DCD are probably generated within spinel stability field, whereas the BDD and the LKD may be derived from melts generated within garnet stability field. Available geological and geochemical data support the emplacement of studied dykes in a stable continental rift tectonic setting, however earlier intrusions have chemistry similar to N-MORB. The available geological, geochemical and geochronological data on the four indentified sets of mafic dykes from the northern Bastar craton indicate their relation to the assembly and break-up of Columbia supercontinent.
DS201607-1316
2016
Gautam, G.C.Srivastava, R.K., Pimentel, M.M., Gautam, G.C.Nd-isotope and geochemistry of an early Paleoproterozoic high Si high Mg boninite-norite suite of rocks in the southern Bastar craton, central India: petrogenesis and tectonic significance.International Geology Review, Vol. 58, 13, pp. 1596-1615.IndiaBoninites

Abstract: Nd-isotope and lithogeochemistry of an early Palaeoproterozoic high-Si high-Mg boninite -norite (BN) suite of rocks from the southern Bastar craton, central India, are presented to understand their nature, origin, and tectonic setting of emplacement. Various types of evidence, such as field relationships, radiometric metamorphic ages, and the global distribution of BN magmatism, suggest emplacement in an intracratonic rift setting, commonly around 2.4 -2.5 Ga. On the basis of geochemistry these high-Si high-Mg rocks are classified as high-Ca boninites, high-Mg norites, and high-Mg diorites. Nd-isotope data indicate that the high-Mg norite and the high-Mg diorite samples are similar, whereas the high-Ca boninites have a different isotopic character. The high-Mg norite and the high-Mg diorite samples have younger TDM model ages than the high-Ca boninites. Geochemical and Nd-isotopic characteristics of the studied rocks indicate some prospect of crustal contamination; however, the possibility of mantle metasomatism during ancient subduction event cannot be ignored. Trace-element modelling suggests that the high-Ca boninites may have crystallized from a magma generated by a comparatively greater percentage of melting of a lherzolite mantle source than the source for the other two varieties. Furthermore, the high-Ca boninite rocks are most likely derived from an Archaean subduction process (the Whundo-type), whereas the other two types are the products of the interaction of subduction-modified refractory mantle wedge and a plume, around the Neoarchaean -Palaeoproterozoic boundary. The emplacement of the high-Mg norites and the high-Mg diorites may be linked to crustal thickening and associated cratonization at the end of the Archaean.
DS201801-0016
2017
Gautam, I.Gautam, I., Bhutani, R., Balakrishnan, S., Chatterjee, A., George, B.G., Ray, J.S.142Nd/144Nd of alkaline magmas in Phenai Mat a complex, Chhota Udaipur, Deccan flood basalt province.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 14.Indiaalkaline rocks

Abstract: The 65 million year old alkaline plug at Phenai Mata Complex, in Chota Udaipur sub province, is often linked to the last pulse of the Deccan volcanism. However, many believe that the Deccan-Reunion mantle plume that was responsible for the generation of flood basalts might not have been the source of Phenai Mata. It, however, could have acted as a heat source for these magmas derived from the subcontinentallithospheric- mantle (SCLM). Since the SCLM is generally considered to be a nonconvective mantle domain it has the potential to preserve some of the geochemical evidence of the early silicate Earth differentiation, e.g., 142Nd anomaly. In search of such signatures we analysed alkali basalts from the complex for their 142Nd/144Nd using high precision thermal ionization mass spectrometry. Whereas the geochemical characterization of these samples confirmed the lithospheric origin of their source magmas, their ? 142Nd compositions are found to be normal with respect to terrestrial standards. We infer that either the mantle source of Phenai Mata does not represent a true non-convective mantle or it is too young to retain any evidence of 146Sm decay.
DS1989-0477
1989
Gautam SenGautam Sen, Jones, R.Experimental equilibration of multicomponent pyroxenes in the spinel peridotite field: implications for practical thermometers and a possiblebarometerJournal of Geophysical Research, Vol. 94, No. B 12, December 10, pp. 17, 871-17, 880GlobalExperimental petrology, Spinel-peridoite field
DS1993-0493
1993
Gautason, B.Gautason, B., Muehlenbachs, K.Oxygen diffusion in perovskite: implications for electrical conductivity In the lower mantleScience, Vol. 260, April 23, pp. 518-521MantleExperimental petrology
DS200712-0101
2007
Gautason, B.Brandon, A.D., Graham, D.W., Waight, T., Gautason, B.188 Os amd 187 Os enrichments and high 3He 4He sources in the Earth's mantle evidence from Iclandic picrites.Geochimica et Cosmochimica Acta, Vol. 71, 18, Sept. pp. 4570-91.Europe, IcelandPicrite
DS200712-0102
2007
Gautason, B.Brandon, A.D., Graham, D.W., Waight, T., Gautason, B.Os He isotope systematics of Iceland picrites: evidence for a deep origin of the Iceland plume.Plates, Plumes, and Paradigms, 1p. abstract p. A119.Europe, IcelandPicrite
DS200712-1127
2007
Gautason, B.Waight, T., Brandon, A.D., Graham, D.W., Gautason, B.Isotopic constraints on picritic magmatism, Iceland.Plates, Plumes, and Paradigms, 1p. abstract p. A1078.Europe, IcelandPicrite
DS2002-0509
2002
Gautheron, C.Gautheron, C., Moreira, M.Helium signature of the subcontinental lithospheric mantleEarth and Planetary Science Letters, Vol.199,1-2,pp.39-47., Vol.199,1-2,pp.39-47.MantleGeochronology
DS2002-0510
2002
Gautheron, C.Gautheron, C., Moreira, M.Helium signature of the subcontinental lithospheric mantleEarth and Planetary Science Letters, Vol.199,1-2,pp.39-47., Vol.199,1-2,pp.39-47.MantleGeochronology
DS200512-0319
2005
Gautheron, C.Gautheron, C., Moreira, M., Allegre, C.He Ne and Ar composition of the European lithospheric mantle.Chemical Geology, Vol. 217, 1-2, April 15, pp. 97-112.Mantle, Germany, France, AustriaXenoliths, geochemistry, rare gases
DS200612-0431
2005
Gautheron, C.Gautheron, C., Cartigny, P., Moreira, M., Harris, J.W., Allegre, C.J.Evidence for a mantle component shown by rare gases, C and N isotopes in polycrystalline diamonds from Orapa (Botswana).Earth and Planetary Science Letters, Vol. 240, 3-4, Dec. 15, pp. 559-572.Africa, BotswanaMineral chemistry - compositional elements
DS200612-1601
2006
Gautheron, C.Zhao, Z., Gautheron, C., Farley, K., Zhang, H., Yu, X., Mo, X.Subcontinental lithospheric mantle origin of the Cenozoic kamafugite in western Qinling, China: evidence from helium isotopes in mantle derived xenoliths.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 16 abstract only.ChinaKamafugite, geochronology
DS202012-2215
2020
Gautheron, C.Gautheron, C., Zeitler, P.K.Noble gases deliver cool dates from hot rocks. Elements, Vol. 16, pp. 303-309.MantleThermochronology

Abstract: Heat transfer in the solid Earth drives processes that modify temperatures, leaving behind a clear signature that we can measure using noble gas thermochronology. This allows us to record the thermal histories of rocks and obtain the timing, rate, and magnitude of phenomena such as erosion, deformation, and fluid flow. This is done by measuring the net balance between the accumulation of noble gas atoms from radioactive decay and their loss by temperature-activated diffusion in mineral grains. Together with knowledge about noble gas diffusion in common minerals, we can then use inverse models of this accumulation-diffusion balance to recover thermal histories. This approach is now a mainstream method by which to study geodynamics and Earth evolution.
DS202108-1277
2021
Gautheron, C.Derycke, A., Gautheron, C., Barbarand, J., Bourbon, P., Aertgeerts, G., Simon-Labric, T., Sarda, P., Pinna-Jamme, R., Boukari, C., Gaurine, F.French Guiana margin evolution: from Gondwana break-up to Atlantic Ocean.Terra Nova, Vol. 33, 4, pp. 415-422. pdfSouth America, French GuianaGuiana Shield

Abstract: Knowledge of the Guiana Shield evolution during the Gondwana break-up is key to a better understanding of craton dynamics and margin response to transtensional opening. To improve this knowledge, we investigated the dynamics and thermal evolution of French Guiana, using several low-temperature thermochronology methods applied to basement rocks, including apatite and zircon (U-Th)/He and apatite fission tracks. Inverse modelling of results allows us to reconstruct the Phanerozoic thermal history of French Guiana margin and to give a preview of the Guiana Shield evolution. Three main events are inferred: firstly, a long-term period of relative stability since ~1.2 Ga, with no strong evidence for any erosional or burial event (>5-7 km); secondly, a heating phase between ~210 and ~140 Ma consistent with the Central Atlantic Magmatic Province-related event. Finally, an exhumation phase between ~140 and ~90 Ma, triggered by the Equatorial Atlantic opening, brought samples close to the surface (<40°C).
DS1975-1029
1979
Gauthier, A.Gauthier, A.Mineralogic, petrographic and geochemical study of the rare earth zone Of the Saint Honore carbonatite. (in French)Msc. Thesis University of Du Quebec A Chicoutimi, (in French), 181pQuebecCarbonatite, St. Honore
DS1983-0597
1983
Gauthier, A.Thiverge, S., Roy, D.W., Chown, E.H., Gauthier, A.Evolution du Complexe Alcalin de St. Honore Apres Sa Mise En PlaceMineralium Deposita, Vol. 18, pp. 267-83.QuebecCarbonatite
DS1983-0598
1983
Gauthier, A.Thivierge, S., Roy, D.W., Chown, E.H., Gauthier, A.Evolution du Complexe Alcalin de St. Honore, Apres Sa Mise En Place.Mineralium Deposita., Vol. 18, PT. 2A, PP. 267-284.Canada, QuebecCarbonatite
DS1989-0138
1989
Gauthier, G.Boily, M., Ludden, J., Gauthier, G.Geochemical studies of the Hearst Matachewan Preissac and Kapuskasing dyke swarms in the Kapuskasing structural zoneGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A123. (abstract.)OntarioTectonics, Kapuskasing Zone
DS201706-1108
2017
Gauthier, M.Trommelen, M.S., Gauthier, M., Kelly, S.E., Hodder, T.J., Wang, Y., Ross, M.Till composition inheritance and overprinting in the Hudson Bay Lowland and across the Precambrian shield.GAC annual meeting, 1p. AbstractCanada, Manitobageochemistry

Abstract: The goal of this work is to determine the effect of multiple glaciations on till composition, in a zone of transition from a multi-till stratigraphy within the Hudson Bay Lowland (HBL) to a single till stratigraphy over the Precambrian shield. The study area, in NE Manitoba, has access to numerous sections that expose multiple tills, in addition to interglacial and postglacial sediments. Sequences of thick till are not easily separated into different units, despite previous field attempts to define four named tills. The compositional transition to thin till overlying the Precambrian Shield in the west is also not well understood. Yet, the two different settings were affected by the same 3+ glacial cycles. The wide range in eastern- and/or northeastern-sourced calcareous clast concentrations, and ‘locally’-sourced shield clast concentrations, combined with variable concentrations of northern-sourced clasts, suggests that the tills of northeastern Manitoba are ‘provenance’ hybrids. Local tills result from the net effect of multiple glacial processes that underwent spatiotemporal variability. Mixed provenance applies not only to surface tills, but to the subsurface tills as well. Preliminary results suggest that carbonate transport across the shield was continuous throughout several glacial cycles, but the bulk of transport likely occurred prior to the most recent glacial cycle. Current work has established a northern-Manitoba ice-flow history using the erosional and depositional record, which encompasses 5 to 7 phases. This new compilation is used in conjunction with ‘till-clast’ stratigraphy and ‘till-geochemistry’ stratigraphy, to identify a new provenance framework for tills in northeastern Manitoba.
DS202001-0012
2019
Gauthier, M.S.Gauthier, M.S., Hodder, T., Ross, M., Kelley, S.E. Rochester, A., McCausland< P. The subglacial mosaic of the Laurentide ice sheet; a study of the interior region of southwestern Hudson Bay.Quaternary Science Reviews, Vol. 214, pp. 1-27.Canada, Manitobageomorphology

Abstract: Reconstructions of past ice-flow provide useful insights into the long-term behaviour of past ice sheets and help to understand how glaciated landscapes are shaped. Here, we present reconstruction of a 10-phase ice-flow history from southwestern Hudson Bay in northeastern Manitoba (Canada), a dynamic region situated between two major ice dispersal centres of the Laurentide Ice Sheet. We utilize a diverse geologic dataset including 1900 field-based erosional indicators, 12 streamlined-landform flowsets, esker and meltwater corridor orientations, 103 till-fabrics analyses, and 1344 till-clast lithology counts. Our reconstruction suggests that both pre-MIS 2 and MIS 2 glaciations followed similar growth patterns, where ice advanced into study area from ice centered to the east (probably in northern Quebec), followed by a switch in ice-flow direction indicating flow from the Keewatin ice centre to the northwest and north. The cause for this switch in ice-flow orientation is uncertain, but the youngest switch may relate to retreat of ice during MIS 3 that then left space for Keewatin-sourced ice to advance over the study area. While modelling experiments indicate widespread cold-based conditions in the study area during the last glacial cycle, uniformly relict landscapes are not common. Instead, the glaciated landscape is palimpsest and commonly fragmented, forming a subglacial bed mosaic of erosional and depositional assemblages that record both shifting ice-flow direction through time and shifting subglacial conditions. Each assemblage formed, or modified, during times of dynamic (warm-based) ice, and later preserved under conditions below or close to the pressure melting point (slow and sluggish, or cold-based).
DS1994-0582
1994
Gauthier, N.Gauthier, N.Campagne de forages, projet diamant-Oasis ( #1144) Novembre-Decembre 1993).Soquem.Quebec Department of Mines, GM 53153, 79p.QuebecExploration - assessment, SOQUEM.
DS1994-0583
1994
Gauthier, N.Gauthier, N.Cas type d'exploration du diamant. (in French)Seventh Colloque Annuel en Ressources Minerales, Universite du Quebec a, p. 6-7. abstract in FrenchQuebecGeochemistry
DS2002-1099
2002
Gauthier-LafaveMossman, D.J., Eigendorf, G., Tokarvk, D., Gauthier-Lafave, Guckert, MelezhikThe search for fullerenes in carbonaceous substances associated with the natural11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 38.GabonFullerenes
DS200412-2155
2004
Gautier, P.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
DS201709-2040
2017
Gautier, S.Parat, F., Baudoin, C., Michel, T., Tiberi, D., Gautier, S.CO2 rich nephelinite differentiation and carbonate silicate immiscibility ( North Tanzanian divergence.)Goldschmidt Conference, abstract 1p.Africa, Tanzaniacarbonatites

Abstract: North Tanzanian Divergence is the first stage of continental break-up of East African Rift and one of the most concentrated areas of carbonatite magmatism with Natron basin in the North (2 Ma-present - Lengai) and Manyara basin in the southern part (0.4-0.9 Ma). The Manyara basin has volcanic activities with mafic magmas as melilitites (Labait), Mg-nephelinites and carbonatite (Kwaraha), and more differentiated magmas as Mg-poor nephelinites (Hanang) recording deep magmatic environment and differentiation in the crust of CO2-rich alkaline magmas. Melilitite and Mg-nephelinite with olivine-cpx-phlogopite record mantle environment at 1.5 GPa-1300°C with water content in melt of 0.1- 0.4 wt% H2O (1-4 ppm in olivine, FTIR). Although fractional crystallization can be considered as an important process during ascent, leading to Mg-poor nephelinite with cpx-melanite-nepheline, complex zonation of cpx (e.g. abrupt change of Mg#, Nb/Ta, and H2O) recorded open system with multiple carbonate-rich silicate immiscibility and melilititic melt replenishment. The low water content of cpx (25 ppm H2O; FTIR) indicates that 0.3 wt% H2O was present during carbonate-rich nephelinite crystallization at crustal level (600 MPa - 1050°C). The interstitial melt entrapped as melt inclusions (MI) in nepheline evolved to CO2-rich and H2O-poor phonolitic composition with 6 wt% CO2 and 1 wt% S at logfO2=FMQ+1 to 1.5 (Fe3+/?Fe=0.3 - S6+/?S=0.55, XANES). At 200 MPa, phonolitic melt in MI reaches carbonate saturation and immiscibility process leads to trachytic melt with high CO2, S and halogen content (0.43 wt% CO2, SIMS; 2 wt% S, 0.84 wt% Cl; 2.54 wt% F) and very low H2O content (<0.1wt%, Raman) and an anhydrous Ca-Na±S,K carbonate liquid. The Ca-Na carbonatitic liquid in Mg-poor nephelinite represents an early stage of the evolution path towards carbonatitic magmatism as observed in Kwaraha and Lengai. Manyara volcanism has similarities with the Natron volcanism with multistage evolution and silicate-carbonatite magmatism but differ by their volatile components (up to 10 H2O wt% in Lengai nephelinite). This can be interpreted in term of depth of partial melting with H2O-CO2 lithospheric mantle source (Natron) and deep anhydrous CO2-rich asthenospheric mantle source in the southern part of rift initiation (Manyara) and percolation of deep CO2-rich silicate liquid leading to lithospheric mantle metasomatism.
DS1996-1435
1996
Gautneb, H.Tontti, M., Gautneb, H., Grenne, T., et al.Map of ore deposits in central FennoscandiaFinland Geological Survey Map, 1: 1, 000, 000FinlandMetallogeny, Deposits
DS200712-0353
2006
Gautron, L.Gautron, L., Greaux, S., Andrault, D., Bolfan Casanova, N., Guignot,N., Bouhifd, M.A.Uranium in the Earth's lower mantle.Geophysical Research Letters, Vol. 33, 23, Dec. 16, L23301MantleUranium
DS200912-0487
2009
Gauvreau, D.McClenaghan, M.B., Gauvreau, D., Kjarsgaard, B.A.Mineral chemistry database for kimberlite surficial sediments and kimberlite boulders from Lake Timiskaming and Kirkland Lake kimberlite fields.Geological Survey of Canada Open File, No. 5833, $7.00 CDCanada, Ontario, QuebecGeochemistry
DS1960-0950
1968
Gavasci, A.T.Gavasci, A.T., Kerr, P.R.Uranium Emplacement at Garnet Ridge ArizonaEconomic Geology, Vol. 63, PP. 859-876.GlobalBlank
DS1960-1108
1969
Gavasci, A.T.Gavasci, A.T., Helmstaedt, H.A Pyroxene Rich Garnet Peridotite Inclusion in an Ultramafic Breccia Dike at Moses Rock, Southeastern Utah.Journal of Geophysical Research, Vol. 74, PP. 6691-6695.United States, Utah, Colorado PlateauBlank
DS1970-0528
1972
Gavasci, A.T.Helmstaedt, H., Anderson, O.L., Gavasci, A.T.Petrofabric Studies of Eclogite, Spinel-websterite, and SpinJournal of Geophysical Research, Vol. 77, PP. 4350-4365.United States, Utah, Arizona, Colorado PlateauBlank
DS1970-0690
1973
Gavasci, A.T.Gavasci, A.T.Investigation on Deformation in Amphibole and Amphibole Bearing Diatremes on the Colorado Plateau.Lamont-doherty Geol. Observ., National Technical Information Service Report, No. 7415, 17P.United States, Colorado PlateauBlank
DS201012-0219
2010
Gavida, G.E.Gavida, G.E., Patton, J.A.Petrography of the Dare mine Knob lamprophyre.Geological Society of America Abstracts, 1/4p.United States, ArkansasLamproite
DS1994-0584
1994
Gavrilenko, B.V.Gavrilenko, B.V., et al.Rare, precious metals and diamond placers - a new source of mineral raw materials resources Baltic shieldRussian Acad. of Sciences, Placers and weathered rock, Nov. 2p.RussiaDiamonds, Placers, alluvials
DS1996-0491
1996
Gavrilenko, B.V.Gavrilenko, B.V., Evzerov, V. Ya., Kazakov, N.V.Placers of northeastern Baltic shield: results and perspectivesLithology and Mineral resources, Vol. 31, No. 3, May. pp. 258-266Baltic ShieldAlluvials
DS1995-0550
1995
Gavrilkova, S.N.Fonarev, V.I., Gavrilkova, S.N., Sultanov, D.M.Metamorphic events in the Precambrian on the southern Aldan Shield, EastSiberia, Russia.Petrology, Vol. 3, No. 2, March-April pp. 152-162.RussiaAldan Shield, metamorphism
DS1994-1818
1994
Gavrilov, E.V.Ustinov, V.I., Ukhanov, A.V., Gavrilov, E.V.On the oxygen isotopic composition of mineral assemblages at different stages of kimberlite formation. (Russian)Geochemistry International (Geokhimiya), (Russian), No. 1, pp. 144-148.RussiaGeochronology, Kimberlite mineralogy
DS1987-0759
1987
Gavrilov, E.Y.Ustinov, V.I., Ukhanov, A.V., Grinenko, V.A., Gavrilov, E.Y.Isotopic composition of oxygen of eclogites from kimberlite pipes Udachnaya and Obnazhennaya. (Technical note). (in Russian)Geochemistry International (Geokhimiya), (Russian), No. 11, November pp. 1637-1641RussiaBlank
DS1994-1819
1994
Gavrilov, Ye. Ya.Ustinov, V.I., Ukhanov, A.V., Gavrilov, Ye. Ya.Oxygen isotope composition of the mineral assemblages in the stages of emplacement of kimberlites.Geochemistry International, Vol. 31, No. 8, pp. 152-156.RussiaGeochronology, mineralogy, Kimberlites
DS1998-0365
1998
GavrilovaDruzhinin, V.S., Karetin, Avtoneev, Gavrilova, TiunovaThe main structures of the crust and upper mantle of the Ural regionDoklady Academy of Sciences, Vol. 360, No. 4, pp. 597-601.Russia, UralsTectonics
DS1999-0389
1999
Gavrilova, S.I.Kuznetsov, I.E., Gavrilova, S.I.Petrology of Karaturgai picrite complex, Central KazakhstanMoscow University of Geol. Bulletin., Vol. 53, No. 3, pp. 7-14.Russia, kazakhstanPicrite
DS201112-0831
2010
GavrishProskurnin, V.F., Petrov, Bagdasarov, Rozinov, Tolmacheva, Larionov, Bilskaya, Gavrish, Mozoleva, PetrushkovOrigin of carbonatites of eastern Taimyr deduced from an isotopic and geochemical study of zircons.Geology of Ore Deposits, Vol. 52, 8, pp. 711-724.RussiaPetrology - carbonatites
DS201504-0194
2015
Gavryushkin, P.Dymshits, A., Sharygin, I., Litasov, K., Shatskiy, A., Gavryushkin, P., Ohtani, E., Suzuki, A., Funakoshi, K.In situ observation of the pyroxene majorite transition in Na2MgSi5O12 using synchroton radiation and Raman spectroscopy of Na-majorite.American Mineralogist, Vol. 100, pp. 378-384.MantleMajorite
DS202007-1175
2020
Gavryushkin, P.N.Sagatova, D., Shatskiy, A., Sagatov, N., Gavryushkin, P.N., Litasov, K.D.Calcium orthocarbonate, Ca2CO4-Pnma: a potential host for subducting carbon in the transition zone and lower mantle.Lithos, in press available, 22p. PdfMantlesubduction

Abstract: A novel structure of calcium orthocarbonate Ca2CO4-Pnma has been discovered using ab-initio crystal structure prediction methods (AIRSS and USPEX) based on the density functional theory. This phase appears above 13 GPa and remains stable to at least 50 GPa and 2000 K according to the calculations within quasi-harmonic approximation. Thus, the discovered phase can be stable at Earth's transition zone and lower mantle P-T conditions. The carbon atoms in the discovered phase are presented in 4-fold coordination, and its structure is similar to the high-pressure and high-temperature ?'H-Ca2SiO4 phase.
DS202008-1439
2020
Gavryushkin, P.N.Sagatova, D., Shatskiy, A., Sagatov, N., Gavryushkin, P.N., Litasov, K.D.Calcium orthocarbonate, CaCO4-Pnma: a potential host for subducting carbon in the transition zone and lower mantle.Lithos, Vol. 370-371, 105637 5p. PdfMantlesubduction

Abstract: A novel structure of calcium orthocarbonate Ca2CO4-Pnma has been discovered using ab-initio crystal structure prediction methods (AIRSS and USPEX) based on the density functional theory. This phase appears above 13 GPa and remains stable to at least 50 GPa and 2000 K according to the calculations within quasi-harmonic approximation. Thus, the discovered phase can be stable at Earth's transition zone and lower mantle P-T conditions. The carbon atoms in the discovered phase are presented in 4-fold coordination, and its structure is similar to the high-pressure and high-temperature ?'H-Ca2SiO4 phase.
DS1999-0602
1999
Gawthorpe, R.L.Ritchie, B.D., Hardy, S., Gawthorpe, R.L.Three dimensional numerical modeling of coarse grained clastic deposition in sedimentary basins.Journal of Geophysical Research, Vol. 104, No. 8, pp. 17, 759-80.AlbertaGeomorphology - fluvial environment
DS1985-0220
1985
Gay, S.P.Jr.Gay, S.P.Jr.Latest Age Dating Results in South Central Kansas: Incompatible with History of Precambrian Events As Reconstructed From Newmag* Basement Mapping Studies.6th. International Conference Basement Tectonics, Held Sante Fe, Septem, P. 17. (abstract.).United States, Central States, KansasGeotectonics, Geophysics
DS1986-0271
1986
Gay, S.P.Jr.Gay, S.P.Jr.Relative timing of tectonic events in newly recognized Precambrian terranes in South Central Kansas USA as determined by residual aeromagnetic data6th. International Conference Basement Tectonics, pp. 153-167KansasUSA, Tectonics
DS1991-0541
1991
Gay, S.P.Jr.Gay, S.P.Jr., Hawley, B.W.Syngenetic magnetic anomaly sources: three examplesGeophysics, Vol. 56, No. 7, July pp. 902-913Nebraska, Utah, BelizeGeophysics -magnetics, Magnetite
DS1992-0518
1992
Gay, S.P.Jr.Gay, S.P.Jr.Epigenetic versus syngenetic magnetite as a cause of magnetic anomaliesGeophysics, Vol. 57, No. 1, January pp. 60-68GlobalGeophysics, Magnetics
DS2002-0511
2002
Gay, S.P.Jr.Gay, S.P.Jr.Jointing, linears and lineaments - the basement connection16th. International Conference On Basement Tectonics '02, Abstracts, 1/2p., 1/2p.GlobalStructure - faults
DS2002-0512
2002
Gay, S.P.Jr.Gay, S.P.Jr.Jointing, linears and lineaments - the basement connection16th. International Conference On Basement Tectonics '02, Abstracts, 1/2p., 1/2p.GlobalStructure - faults
DS201707-1376
2017
Gazel, E.Trela, J., Gazel, E., Sobolev, A.V., Moore, L., Bizimis, M.The hottest lavas of the Phanerozoic and the survival of Archean reservoirs.Nature Geoscience, Vol. 10, 6, pp. 451-456.Mantleplumes

Abstract: Large igneous provinces and some hotspot volcanoes are thought to form above thermochemical anomalies known as mantle plumes. Petrologic investigations that support this model suggest that plume-derived melts originated at high mantle temperatures (greater than 1,500?°C) relative to those generated at ambient mid-ocean ridge conditions (about 1,350?°C). Earth’s mantle has also cooled appreciably during its history and the temperatures of modern mantle derived melts are substantially lower than those produced during the Archaean (2.5 to 4.0 billion years ago), as recorded by komatiites (greater than 1,700?°C). Here we use geochemical analyses of the Tortugal lava suite to show that these Galapagos-Plume-related lavas, which formed 89 million years ago, record mantle temperatures as high as Archaean komatiites and about 400?°C hotter than the modern ambient mantle. These results are also supported by highly magnesian olivine phenocrysts and Al-in-olivine crystallization temperatures of 1,570 ± 20?°C. As mantle plumes are chemically and thermally heterogeneous, we interpret these rocks as the result of melting the hot core of the plume head that produced the Caribbean large igneous province. Our results imply that a mantle reservoir as hot as those responsible for some Archaean lavas has survived eons of convection in the deep Earth and is still being tapped by mantle plumes.
DS201711-2532
2017
Gazel, E.Trela, J., Gazel, E., Sobolev, A.V., Moore, L., Bizimis, M., Jicha, B., Batanova, V.G.The hottest lavas of the Phanerozoic and the survival of deep Archean reservoirs.Nature Geoscience, Vol. 10, pp. 451-456.Mantlegeodynamics - plumes

Abstract: Large igneous provinces and some hotspot volcanoes are thought to form above thermochemical anomalies known as mantle plumes. Petrologic investigations that support this model suggest that plume-derived melts originated at high mantle temperatures (greater than 1,500?°C) relative to those generated at ambient mid-ocean ridge conditions (about 1,350?°C). Earth’s mantle has also cooled appreciably during its history and the temperatures of modern mantle derived melts are substantially lower than those produced during the Archaean (2.5 to 4.0 billion years ago), as recorded by komatiites (greater than 1,700?°C). Here we use geochemical analyses of the Tortugal lava suite to show that these Galapagos-Plume-related lavas, which formed 89 million years ago, record mantle temperatures as high as Archaean komatiites and about 400?°C hotter than the modern ambient mantle. These results are also supported by highly magnesian olivine phenocrysts and Al-in-olivine crystallization temperatures of 1,570 ± 20?°C. As mantle plumes are chemically and thermally heterogeneous, we interpret these rocks as the result of melting the hot core of the plume head that produced the Caribbean large igneous province. Our results imply that a mantle reservoir as hot as those responsible for some Archaean lavas has survived eons of convection in the deep Earth and is still being tapped by mantle plumes.
DS1996-0085
1996
Gazenave, A.Barlier, F., Le Traon, P.-Y., Gazenave, A.Point sur les missions d'altimetrie spatiale TOPX/POSEIDON et ERS-1C.r. Academy Of Science Paris, Vol. 323, 11a pp. 737-753.GlobalMarine oceanography, Coastal areas - general not specific to diamonds
DS200512-0320
2004
Gazit, O.Gazit, O., Navon, O., Halicz, L., Stein, M.The petrogenesis and thermal history of lower crustal xenoliths from Karnei-hitin, northern Israel.Israel Geological Society, p. 34. 1p. Ingenta 1045591078.Europe, IsraelGeothermometry
DS201412-0245
2014
Gazley, M.F.Fisher, L., Gazley, M.F., Baensch, A., Barnes, S.J., Cleverely, J., Duclaux, G.Resolution of geochemical and lithostratigraphic complexity: a workflow for application of portable X-ray fluorescence to mineral exploration.Geochemistry: Exploration, Environment, Analysis, Vol. 14, 2, pp. 139-148.TechnologyGeochemistry
DS1970-0514
1972
Gbakpoma, M.Gbakpoma, M.Activite Miniere de la Republique Centrafricaine En 1971Centrafricain Dir. Mines, No. 5Central African Republic, West AfricaDiamond Mining
DS200612-0432
2005
Gberie, L.Gberie, L.A dirty war in West Africa: the RUF and the destruction of Sierra Leone.Indiana University Press, Bloomington, 224p. $ 25.Africa, Sierra LeoneBook - review in PAC Other Facets no. 19, p. 4.
DS1995-0301
1995
Ge, L.Chekhov, B.M., Ge, L.Tectonics of the Indochinese collision beltRussian Geology and Geophysics, Vol. 36, No. 12, pp. 1-14southeast Asia, Vietnam, China, MyanmarTectonics, Collision belt
DS202205-0732
2022
Ge, R.Wu, H., Zhu, W., Ge, R.Evidence for carbonatite derived from the Earth's crust: the late Paleoproterozoic carbonate-rich magmatic rocks in the southeast Tarim Craton, northwest China.Precambrian Research, Vol. 369, 106425 20p.Chinacarbonatite

Abstract: Carbonatites are generally accepted as derived from the mantle, whereas viewpoint of carbonatitic melt formed at crust level is considered marginal. Here we document large-scale (?17?km2) igneous carbonate-rich rocks in the southeast Tarim Craton that were formed within the crust. These rocks exhibit clear intrusive contact with the wall-rocks and contain diverse xenolith, indicating an igneous origin. Zircon U-Pb dating reveals that they were emplaced at ca. 1.94-1.92 and 1.87-1.86?Ga, respectively. ?18O values in zircons (5.7-13.7‰) are higher than those crystallized in equilibrium with mantle melt. Total REE content is 1-2 magnitude lower than that of mantle carbonatite and shows weak fractionation of HREE. REE modeling reveals that the samples cannot be produced by partial melting of carbonated MORB at mantle conditions. The studied samples have positive ?13CV-PDB values (4.2-15.7‰), which are distinct from the mantle carbonatite but comparable to sedimentary carbonates. C-O-Sr-Nd isotope modelling indicates that the compositions of the studied samples cannot be produced by evolution of mantle carbonatite. Integrating these lines of evidence, we conclude that the studied carbonate-rich magmatic rocks were derived from partial melting of impure marble at crustal level via fluid-present melting. These carbonatites probably represent the initial magmatic record of tectonic extension of the late Paleoproterozoic collisional orogenic belt in the southern margin of the Tarim craton. The positive carbon excursion recorded by the high ?13CV-PDB values probably corresponds to the global Paleoproterozoic Lomagundi-Jatuli event. Our study implies that partial melting of sedimentary carbonates is more common than previously thought, which has significant impacts on crust rheology and global carbon cycling
DS201312-0992
2013
Ge, T-y.Yang, Z-j., Liang, R., Zeng, X-q., Ge, T-y., Al Qun, Zhenh, Y-l., Peng, M-s.Study on the micro-infrared spectra and origin of polycrystalline diamonds from Mengyin kimberlite pipes.Spectroscopy and Spectral Analysis, Vol. 32, 8, pp. 1512-1518.ChinaDeposit - Mengyin
DS201911-2555
2019
Ge, X.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.
DS1985-0034
1985
GE, Yuan zhongxin.Bai, GE, Yuan zhongxin.On the Rare Earth Elements (ree) Rich Carbonatites.*chiIn: New frontiers Rare Earth Science Applications Proceedings International Conference Rare, Vol. 1, pp. 45-48ChinaCarbonatite, Rare Earth
DS1993-1772
1993
Ge BaiWu Chengyu, Ge Bai, Zhongxin Yuan, Nakajima, T., Ishihara, S.Proterozoic metamorphic rock hosted Zirconium, Yttrium and heavy rare earth elements (HREE) mineralization in the Dabie Mountain area.International Geology Review, Vol. 35, No. 9, pp. 898-919.ChinaCarbonatite, Rare earth
DS1986-0272
1986
Geach, C.L.Geach, C.L.DIAMOND EXPLORATION IN WESTERN AUSTRALIA. #1Geology Today, IN PRESSAustralia, Western AustraliaREVIEW.
DS1986-0273
1986
Geach, C.L.Geach, C.L.Diamond exploration in western AustraliaGeology Today, Vol. 2, No. 1, pp. 16-20AustraliaPopular overview
DS1991-0542
1991
Geach, C.L.Geach, C.L.Byro sub-basin as a potential diamond bearing provinceProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 130-132AustraliaGeophysics, Petrography, lamproite
DS1993-0494
1993
Geake, E.Geake, E.Buckyball film is no rough diamondNew Scientist, Vol. 138, No. 1877, June 12, p. 18GlobalFullerenes, Buckyball
DS1990-0525
1990
Geballe, T.H.Geballe, T.H., Pohl, R.O., Seitz, R.Cool diamonds. Letters to Science in response to E. Marshall's articleScience, Vol. 250, November 30, pp. 1194-1195GlobalDiamond synthesis, Thermal conductivity
DS202005-0733
2020
Geballe, Z.M.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.
DS1975-1030
1979
Gebauer, D.Gebauer, D., Grunenfelder, M.Uranium-lead-zirconium and Rubidium-strontium Mineral Dating of eclogites and Their Country Rocks. Example: Munchberg Gneiss Massif, Northeast bavaria.Earth and Planetary Science Letters, Vol. 42, PP. 35-44.GlobalRelated Rocks
DS200512-0634
2004
Gebauer, D.Liati, A., Franz, L., Gebauer, D., Fanning, C.M.The timing of mantle and crustal events in South Namibia, as defined by SHRIMP dating of zircon domains from a garnet peridotite xenolith of the Gideon Kimberlite province.Journal of African Earth Sciences, Vol. 39, 3-5, pp. 147-157.Africa, NamibiaGeochronology
DS200512-0635
2004
Gebauer, D.Liati, A., Franz, L., Gebauer, D., Fanning, C.M.The timing of mantle and crustal events in South Namibia as defined by SHRIMP dating of zircon domains from a garnet peridotite xenolith of the Gibeon kimberlite province.Journal of African Earth Sciences, Vol. 39, 3-5, June pp. 147-157.Africa, NamibiaGeochronology, Pipe Hanaus 1, crustal events
DS1995-0941
1995
Gebert, J.Kerr, D.E., Dredge, L.A., Ward, B.C., Gebert, J.Quaternary geology and implications for drift prospecting Napaktulik @Point Lake and ContwyotoGeological Survey of Canada (GSC) Paper, No. 1995-E, pp. 201-9.Northwest TerritoriesGeomorphology
DS1994-0585
1994
Gebert, J.S.Gebert, J.S., Jackson, V.A.Preliminary compilation of the Point Lake Contwyoto Napultulik Kathawachaga Lakes area.Diand., EGS 1994-2, map.Northwest TerritoriesGeology
DS1998-0481
1998
Gebmann, C.K.Gebmann, C.K., Rubie, D.C.The effect of temperature on the partioning of nickel, cobalt, chromium and vanadium at 9 GPaGeochimica et Cosmochimica Acta, Vol. 62, No. 5, pp. 867-82.MantleEarth core, formation
DS202004-0514
2020
Gebralle, Z.M.Gebralle, Z.M., Sime, N., Badro, J., van Kekn, P.E.Thermal conductivity near the bottom of the Earth's lower mantle: mesurements of pyrolite up to 120 GPa and 2500 K. Earth and Planetary Science Letters, Vol. 536, 116161 7p. 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.
DS1990-0197
1990
Gebran, A.Best, J.A., Barazangi, M., Al-Saad, D., Sawaf, T., Gebran, A.Bouguer gravity trends and crustal structure of the Palmyride Mountain Belt and surrounding northern Arabian platform in SyriaGeology, Vol. 18, No. 12, December pp. 1235-1239SyriaGeophysics -gravity, Craton
DS1859-0131
1859
Geddes, G.Geddes, G.Survey of OnondagaNew York State Agricultural Society, Vol. 9, CHAPT. 2, P. 247.United States, Appalachia, New YorkDiamond Occurrence
DS201707-1340
2017
Gee, D.Klonowska, I., Janak, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.Microdiamond on Areskutan confirms UHP metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, Vol. 35, 5, pp. 541-564.Europe, SwedenUHP

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here we present a new occurrence of diamond within the Seve Nappe Complex of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in-situ as single and composite (diamond + carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet + phengite + kyanite + rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P-T conditions for this stage are 830-840 ºC and 4.1-4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850-860 ºC and 1.0-1.1 GPa, leading to formation of Ca,Mg-poor garnet + biotite + plagioclase + K-feldspar + sillimanite + ilmenite + quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th-U-Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the Seve Nappe Complex, provide compelling arguments for regional (at least 200 km along the unit) UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS2000-0321
2000
Gee, D.G.Gee, D.G., Artemieva, I.M.Europrobe - multidisciplinary studies of the lithosphere across a United Europe.Igc 30th. Brasil, Aug. abstract only 1p.EuropeGeophysics - seismics, Geochemistry
DS200512-0321
2005
Gee, D.G.Gee, D.G., Pease, V.The Neoproterozoic Timanide Orogen of eastern Baltica.Geological Society of London, Memoir M0030 160p.Baltic Shield, Norway, Finland, RussiaBook - East European Craton, subduction
DS200712-0354
2006
Gee, D.G.Gee, D.G., Stephenson, R.A.European lithosphere dynamics.Geological Society of London , Memoir 32, Dec. 672p. $ 225.EuropeBook - tectonics
DS200712-0576
2006
Gee, D.G.Kostyuchenko, S., Sapozhnikov, R., Egorkin, A., Gee, D.G., Berzin, R., Solodilov, L.Crustal structure and tectonic model of northeastern Baltica, based on deep seismic and potential field data.Geological Society of London Memoir, No. 32, pp. 521-540.Europe, Baltic ShieldTectonics, geophysics
DS201607-1347
2016
Gee, D.G.Gee, D.G.Microdiamonds in the Scandinavian Caledonides related to Ordovician continent arc and Siluro-Devonian continent collision.IGC 35th., Session The Deep Earth 1 p. abstractEurope, Scandinavia, SwedenMicrodiamonds
DS201702-0221
2017
Gee, D.G.Klonowska, I., Janak, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.G., sasinkova, V.Microdiamond on Areskutan confirms regional UHP metamorphism in the Seve Nappe complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, in press availableEurope, Sweden, NorwayUHP

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here we present a new occurrence of diamond within the Seve Nappe Complex of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in-situ as single and composite (diamond + carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet + phengite + kyanite + rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P-T conditions for this stage are 830-840 °C and 4.1-4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850-860 °C and 1.0-1.1 GPa, leading to formation of Ca,Mg-poor garnet+biotite+ plagioclase+K-feldspar+sillimanite+ilmenite+quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th-U-Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the Seve Nappe Complex, provide compelling arguments for regional (at least 200 km along strike of the unit). UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS201703-0422
2017
Gee, D.G.Klonowska, I., Janak, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.G., Sasinkova, V.Microdiamond on Areskutan confirms regional UHP metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, in press availableEurope, SwedenMicrodiamond

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here, we present a new occurrence of diamond within the Seve Nappe Complex (SNC) of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in situ as single and composite (diamond+carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet+phengite+kyanite+rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P-T conditions for this stage are 830-840 °C and 4.1-4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850-860 °C and 1.0-1.1 GPa, leading to formation of Ca,Mg-poor garnet+biotite+plagioclase+K-feldspar+sillimanite+ilmenite+quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th-U-Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the SNC, provide compelling arguments for regional (at least 200 km along strike of the unit) UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS201709-2018
2017
Gee, D.G.Klonowska, I., Janek, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.G., Sasinkova, V.Microdiamond on Areskutan confirms regional UHP metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, Vol. 35, 5, pp. 541-564.Europe, Scandinaviamicrodiamond

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here, we present a new occurrence of diamond within the Seve Nappe Complex (SNC) of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in situ as single and composite (diamond+carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet+phengite+kyanite+rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P–T conditions for this stage are 830–840 °C and 4.1–4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850–860 °C and 1.0–1.1 GPa, leading to formation of Ca,Mg-poor garnet+biotite+plagioclase+K-feldspar+sillimanite+ilmenite+quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th–U–Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the SNC, provide compelling arguments for regional (at least 200 km along strike of the unit) UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS201506-0281
2015
Gee, J.S.Kent, D.V., Kjarsgaard, B.A., Gee, J.S., Muttoni, G., Heaman, L.M.Tracking the Late Jurassic apparent ( or true) polar shift in U-Pb-dated kimberlites from cratonic North America ( Superior Province of Canada).Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 4, pp. 983-994.Canada, Ontario, TimiskamingDeposit - Peddie
DS1987-0241
1987
Gee, L.L.Gee, L.L., Sack, R.O.Experimental petrology of melilites-nephelinitesGeological Society of America, Vol. 19, No. 7 annual meeting abstracts, p.673. abstracDemocratic Republic of CongoMelilite
DS1988-0238
1988
Gee, L.L.Gee, L.L.Experimental petrology of melilitites-nephelinitesMsc. Thesis, Purdue University, 56pGlobalExperimental petrology, Melilitites
DS1988-0239
1988
Gee, L.L.Gee, L.L., Sack, R.O.Experimental petrology of melilite nephelinitesJournal of Petrology, Vol. 29, pt. 6, December pp. 1233-1255East Africa, HawaiiMt. Nyiragongo, Melilite
DS200612-1421
2006
Gee, M.A.Thirwall, M.F., Gee, M.A., Lowry, D., Mattey, D.P., Murton, B.J., Taylor, R.N.Low 180 in the Icelandic mantle and its origins: evidence from Reykjanes Ridge and Icelandic lavas.Geochimica et Cosmochimica Acta, Vol. 70, 4, pp. 993-1019.Europe, IcelandGeochronology
DS1997-1142
1997
Gee, M.A.M.Taylor, R.N., Thirwall, M.F., Gee, M.A.M.Isotopic constraints on the influence of the Icelandic plumeEarth and Planetary Science Letters, Vol. 148, No. 1-2, Apr. 1, pp. E1-GlobalPlumes, hotspots, Geochronology
DS1975-1031
1979
Gee, R.D.Gee, R.D.Structure and Tectonic Style of the Western Australian ShieldTectonophysics, Vol. 58, pp. 327-369.AustraliaCraton - Yilgarn Block
DS1981-0177
1981
Gee, R.D.Gee, R.D., Baxter, J.L., Wilde, S.A., Wiliams, I.R.Crustal Development in the Archean Yilgarn Block, Western AustraliaGeological Society of Australia Spec. Publishing, No. 7, pp. 43-56.AustraliaTectonics - Craton
DS1990-0526
1990
Geerthsen, K.Geerthsen, K., Maher, M.J.Gravity signature of an Archean craton/Proterozoic mobile belt transition in southern AfricaSociety of Exploration Geophysicists, 60th. Annual Meeting held, San, Vol. 1, pp. 613-616. Extended abstractSouth AfricaGeophysics -gravity, Craton
DS200812-0390
2008
Gefen, S.Gefen, S., Lieberman, R.An interview with newly elected president of the WFDB. World Federation of Diamond Bourses.The Israeli Diamond Industry, July 8, 3p.GlobalNews item - WFDB
DS1998-0790
1998
GehorKorobeinikov, A.N., Mitrofanov, Gehor, Laajoki, PavlovGeology and copper sulphide mineralization of the Salmagorskii ring igneouscomplex, Kola Peninsula.Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2033-41.Russia, Kola PeninsulaAlkaline rocks, Salmagorsky Complex
DS2000-0525
2000
Gehor, S.Korobeinikov, A.N., Lajoki, K., Gehor, S.Nepheline bearing feldspar syenite (pulaskite) Khibin a pluton, Kola Peninsula -petrological investigationJournal of Asian Earth Science, Vol. 18, No.2, Apr. pp.205-12.Russia, Kola PeninsulaPetrology, Pulaskite
DS200612-0997
2004
Gehor, S.O'Brien, H., Ramo, T., Gehor, S.Carbonatite-kimberlite-alkaline rock field trip to southern and central Finland.Siilinjarvi, Kaavi-Kuopio, Kuhmo, IivaaraFinland Field Trip Guidebook June 2-4, 2004, 30p.Europe, FinlandGuidebook
DS200712-0825
2007
Gehor, S.Pehkonen-Ollila, A.R., Gehor, S.Mineral chemistry of pyrochlore in residually inherited Fe P Nb laterite ore bodies at Sokli carbonatite complex.Plates, Plumes, and Paradigms, 1p. abstract p. A771.Europe, FinlandSokli
DS1998-1265
1998
GehrelsRudnick, R.L., Ireland, T.R., Gehrels, Irving, ChesleyDating mantle metasomatism: uranium-lead (U-Pb) geochronology of zircons in cratonic mantle xenoliths from ...7th. Kimberlite Conference abstract, pp. 754-6.Montana, TanzaniaGeochronology, Deposit - Highwood Mountains, Labait
DS1999-0614
1999
GehrelsRudnick, R.L., Ireland, Gehrels, Irving, Chesley HancharDating mantle metasomatism uranium-lead (U-Pb) geochronology of zircons in cratonic mantle xenoliths ...7th International Kimberlite Conference Nixon, Vol. 2, pp. 728-35.Montana, TanzaniaGeochronology, SHRIMP, analyses, Metasomatism, Highwood Mountains, Labait
DS201312-0506
2013
GehrelsKosler, J., Slama, Belousova, Corfu, Gehrels, Gerdes, Horstwood, Sircombe, Sylvester, Tiepolo, Whitehouse, WoodheadU-Pb detrital zircon analysis - results of an inter-laboratory comparison. (not specific to diamonds)Geostandards and Geoanalytical Research, Vol. 37, 3, pp. 243-259.GlobalZircon analyses
DS200612-0306
2006
Gehrels, G.Darby, B.J., Gehrels, G.Detrital zircons for the North Chin a Block.Journal of Asian Earth Sciences, Vol. 26, 6, May pp. 637-648.ChinaGeochronology - not specific to diamonds
DS200612-0518
2006
Gehrels, G.Hacker, B.R., Wallis, S.R., Ratschbacher, L., Grove, M., Gehrels, G.High temperature geochronology constraints on the tectonic history and architecture of the ultrahigh pressure Dabie-Sulu Orogen.Tectonics, Vol. 25, 5, TC5006ChinaUHP, tectonics
DS200712-1205
2007
Gehrels, G.Yin, A., Manning, C.E., Lovera, O., Menold, C.A., Chen, X., Gehrels, G.Early Paleozoic tectonic and thermomechanical evolution of ultrahigh pressure (UHP) metamorphic rocks in the northern Tibetan Plateau, northwest China.International Geology Review, Vol. 49, 8, pp. 681-716.ChinaUHP
DS201412-0277
2014
Gehrels, G.Gehrels, G.Detrital zircon U-Pb geochronology applied to tectonics.Annual Review of Earth and Planetary Sciences, Vol 42, pp. 127-149.MantleGeochronology
DS1989-1333
1989
Gehrels, G.E.Samson, S.D., McClelland, W.C., Patchett, P.J., Gehrels, G.E.Evidence from neodynium isotopes for mantle contributions to Phanerozoiccrustal genesis in the Canadian CordilleraNature, Vol. 337, No. 6209, Feb. 23, pp. 705-708CordilleraIsotope, Mantle genesis
DS1990-1298
1990
Gehrels, G.E.Samson, S.D., Patchett, P.J., Gehrels, G.E., Anderson, R.G.neodymium and Strontium isotopic characterization of the Wrangellia Terrane and implications for crustal growth of the Canadian CordilleraJournal of Geology, Vol. 98, pp. 749-762British ColumbiaTerrane - Wrangellia, Geochronology
DS1993-1489
1993
Gehrels, G.E.Smith, M.T., Dickinson, W.R., Gehrels, G.E.Contractual nature of Devonian-Missisippian Antler tectonism along The north American continental marginGeology, Vol. 21, No. 1, January pp. 21-24Cordillera, Nevada, Yukon, British ColumbiaTectonics, Orogeny
DS1998-0482
1998
Gehrels, G.E.Gehrels, G.E., Ross, G.M.Detrital zircon geochronology of Neoproterozoic to Permian miogeo clinal strat a in British Columbia @ Alta.Canadian Journal of Earth Sciences, Vol. 35, No. 12, pp. 1380-1401.AlbertaWestern Canada Sedimentary Basin
DS200812-0926
2008
Gehrels, G.E.Prokopiev, A.V., Toro, J., Miller, E.L., Gehrels, G.E.The paleo-Lena River - 200 m.y. of transcontinental zircon transport in Siberia.Geology, Vol. 36, 9, Sept. pp. 699-702.RussiaVerkhoyansk area
DS201312-0605
2013
Gehrels, G.E.Miller, E.L., Solovev, A.V., Prokopiev, A.V., Toro, J., Harris, D., Kuzmichev, A.B., Gehrels, G.E.Triassic river systems and the paleo-Pacific margin of northwestern Pangea. Lena River systemGondwana Research, Vol. 23, 4, pp. 1631-1645.RussiaSource areas
DS2003-0209
2003
Gei, D.Carcione, J.M., Finetti, I.R., Gei, D.Seismic modeling of the the Earth's deep crustGeophysics, Vol. 68, 2, pp. 656-64.MantleGeophysics - seismics
DS200412-0271
2003
Gei, D.Carcione, J.M., Finetti, I.R., Gei, D.Seismic modeling of the the Earth's deep crust.Geophysics, Vol. 68, 2, pp. 656-64.MantleGeophysics - seismics
DS1989-0478
1989
Geiger, C.A.Geiger, C.A., Guidotti, C.V.Precambrian metamorphism in the southern Lake Superior region and its bearing on crustal evolutionGeoscience Wisconsin, Vol. 13, July pp. 1-33Minnesota, Wisconsin, Michigan, MidcontinentTectonics, Crustal evolution
DS1992-0041
1992
Geiger, C.A.Armbruster, T., Geiger, C.A., Lager, G.A.Single-crystal x-ray structure study of synthetic pyrope almandine garnet sat 100 and 293 kAmerican Mineralogist, Vol. 77, No. 5, 6, May-June pp. 512-521GlobalGarnet mineralogy, Synthetic pyrope
DS1992-0568
1992
Geiger, C.A.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
Geiger, C.A.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
DS1998-0483
1998
Geiger, C.A.Geiger, C.A.Could the effect of order-disorder in garnet be important for upper mantlepetrology?7th International Kimberlite Conference Abstract, pp. 248-9.MantleGarnet mineralogy
DS2000-0322
2000
Geiger, C.A.Geiger, C.A., Stahl, A., Rossman, G.R.Single crystal IR and UV VIS spectroscopic measurements on transition metal bearing pyrope: incorporation...European Journal of Mineralogy, Vol. 12, pp. 259-71.GlobalPyrope mineralogy - hydroxide in garnet, Spectroscopy - pyrope
DS200512-0696
2005
Geiger, C.A.Matveev, S., Portnyagin, M., Ballhaus, C., Brooker, R., Geiger, C.A.Spectrum of phenocryst olivine as an indicator of silica saturation in magmas.Journal of Petrology, Vol. 46, 3, pp. 603-614.MantleMagmatism
DS200812-0391
2008
Geiger, C.A.Geiger, C.A.Silicate garnet: a micro to macroscopic (re)view.American Mineralogist, Vol. 93, pp. 360-372.TechnologyGarnet mineralogy - not specific to diamonds
DS201412-0278
2013
Geiger, C.A.Geiger, C.A.Garnet: a key phase in nature, the laboratory, and technology.Elements, Vol. 9, 6, Dec. pp. 447-452.MantleCrystal chemistry
DS201507-0326
2015
Geiger, C.A.Milani, S., Nestola, F., Alvaro, M., Pasqual, D., Mazzucchelli, M.L., Domeneghetti, M.C., Geiger, C.A.Diamond -garnet geobarometry: the role of garnet compressibility and expansivity.Lithos, Vol. 227, pp. 140-147.TechnologyGeobarometry
DS201608-1407
2016
Geiger, C.A.Geiger, C.A.A tale of two garnets: the role of solid solution in the development toward a modern mineralogy.American Mineralogist, Vol. 101, pp. 735-1749.TechnologyGarnet classification

Abstract: This article reviews the development of mineralogy as a science by focusing largely on the common silicate garnets of general formula {X3}[Y2](Si3)O12. It tells of important discoveries, analyses, and proposals by various scientists relating to crystallography, crystal structures, isomorphism, and solid solution starting in Europe in the late 1700s. The critical recognition of the importance of ionic size of atoms in determining crystal-chemical properties and solid-solution behavior is emphasized. The two garnet species “pyralspite” and “(u)grandite,” which were considered to represent two independent solid-solution series, were introduced by N.H. Winchell and A.N. Winchell (1927) in their well-known book Elements of Optical Mineralogy. Critical comments on the assumptions behind the classification scheme have been pointed out for at least 50 yr, but it remains in use. There is more, though, behind this garnet classification scheme than just simple terminology. There are a long series of scientific discoveries and advances that are largely forgotten by the broader mineralogical community. They begin, here, with the work of the “father of crystallography,” René-Just Haüy, concerning the microscopic nature of crystals around 1780 and include later discoveries and proposals by Mitscherlich, Beudant, Wollaston, and Kopp relating to isomorphism and solid-solution behavior all before 1850. A second key era started with the discovery of X-ray diffraction in 1912 that allowed the atomic structures of crystals and, furthermore, atomic and ion radii to be determined. In terms of isomorphism and solid solution, the proposals and studies of Vegard, Zambonini, Wherry, A.N. Winchell, and the “father of crystal chemistry” Goldschmidt are briefly discussed. The recognition of the sizes of atoms and ions, along with an understanding of chemical bonding behavior in crystals, was critical in the establishment of what can be termed “modern mineralogy,” a quantitative science as it is largely understood today that emerged by the mid-1930s. The silicate garnet system pyrope-almandine-spessartine-grossular-andradite-uvarovite shows extensive homovalent substitutional solid solution over two structural sites and complete compositional variation between “pyralspite species” and “ugrandite species” has been documented. Thus, the prerequisites behind the terms “pyralspite” and “(u)grandite,” as originally formulated and often accepted even today, are incorrect and use of this classification is not recommended. Diffraction determinations of the volumes of garnet end-members and volumes of mixing of garnet solid solutions give physical insight into solid-solution behavior. Today, investigations of local structural and crystal-chemical properties, together with determinations of lattice strain and thermodynamic mixing properties, of silicate solid solutions are leading to an ever more quantitative understanding of mineral behavior from the microscopic to macroscopic level.
DS2001-0358
2001
Geiger, H.D.Geiger, H.D., Cook, F.A.Analyses of crustal structure from band pass and directionally filtered potential field data: an exampleCanadian Journal of Earth Sciences, Vol. 38, No. 6, June pp. 953-61.British Columbia, YukonGeophysics - potential
DS200512-0322
2004
Geiger, M.Geiger, M., Clark, D.N., Mette, W.Reappraisal of the timing of the breakup of Gondwana based on sedimentalogical and seismic evidence from the Morondava Basin, Madagascar.Journal of African Earth Sciences, Vol. 38, 4, March pp. 363-381.Africa, MadagascarGeophysics - seismics, tectonics
DS1920-0382
1928
Geijer, P.Geijer, P.Alnoitic Dikes from the Coast Region of Lulea and Kalix in Northern Sweden.Fennia., Vol. 50, No. 11, PP. 2-16.Sweden, ScandinaviaAlnoite
DS200512-0384
2005
Geiko, Y.V.Gursky, D.S., Metalidi, V.S., Pryhodko, V.L., Geiko, Y.V.Prospects of diamond bearing ability in Ukraine and trends of geological prospecting works.Gems & Gemology, abstracts Mineralogical Journal (Ukraine) Vol. 26, 1, pp. 7-17. *** in English, Vol. 41, 2, Summer p. 194. abstract onlyEurope, UkraineStructure, occurrences
DS1860-0142
1871
Geinitz, H.B.Geinitz, H.B.Sued afrikanische Diamanten #1Neues Jahrbuch f?r Mineralogie, PP. 767-768.Africa, South Africa, Cape Province, Vaal RiverHistory, Alluvial Placers
DS2001-1248
2001
GeipelWonik, T., Trippler, Geipel, Grienwald, PashkevitchMagnetic anomaly map for northern western and eastern EuropeTerra Nova, Vol. 13, pp. 203-13.EuropeGeophysics - magnetics
DS200612-0038
2006
Geirsson, H.Arnadottir, T., Jiang, W., Feigl, K.L., Geirsson, H., Sturkell, E.Kinematic models of plate boundary deformation in southwest Iceland derived from GPS observations.Journal of Geophysical Research,, Vol. 111, B7, B7402Europe, Iceland, mantleGeophysics - seismics
DS1989-1605
1989
GeisWest, G.F., Harley, P., Green, A.G., Milkereit, B., Cook, F., GeisReflection seismic profiling of the Kapuskasing structural zoneGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A124. (abstract.)OntarioTectonics, Kapuskasing Zone
DS1994-0479
1994
Geis, Edwards eta l.Eaton, D.W., Milkereit, Kanasewich, Geis, Edwards eta l.Seismic expression of basment cover interaction in central AlbertaLithoprobe Report, No. 37, pp. 142-63.AlbertaGeophysics - seismics
DS1988-0240
1988
Geis, M.W.Geis, M.W., Rathman, D.D., Zayhowski, J.J., Smythe, D.L., SmithHomoepitaxial semiconducting diamondNational Technical Information Service AD-A202 349/7, 5p. $ A02 $ 10.95GlobalElectrical characteristics, Diamond
DS1992-0519
1992
Geis, M.W.Geis, M.W., Angus, J.C.Diamond film semiconductorsScientific American, Vol. 267, No. 4, October pp. 84-89GlobalLayman's overview CVD., Diamond film conductors
DS1989-1198
1989
Geis, W.Percival, J.A., Green, A.G., Milkereit, B., Cook, F.A., Geis, W.Seismic reflection profiles across deep continental crust exposed in the Kapuskasing uplift structureNature, Vol. 342, No. 6248, November 23, pp. 416-419OntarioGeophysics -seismic, Kapuskasing rift zone
DS1990-0527
1990
Geis, W.T.Geis, W.T., Cook, F.A., Green, A.G., Milkereit, B., Percival, J.A.Thin thrust sheet formation of the Kapuskasing structural zone revealed bylithoprobe seismic reflection dataGeology, Vol. 18, No. 6, June pp. 513-516OntarioGeophysics -Seismics, Kapuskasing Zone
DS1990-0528
1990
Geis, W.T.Geis, W.T., Cook, F.A., Green, A.G., Milkereit, B., Percival, J.A.Thin thrust sheet formation of the Kapuskasing structural zone revealed by lithoprobe seismic reflection dataGeology, Vol. 18, No. 6, June pp. 513-516OntarioGeophysics, Kapuskasing Zone
DS1988-0241
1988
Geiser, P.A.Geiser, P.A.Mechanisms of thrust propagation: some examples and implications for the analysis of Over thrust terranesJournal of Structural Geology, Vol. 10, No. 8, pp. 829-845GlobalStructure, Thrust/LPS
DS1989-0479
1989
Geiser, P.A.Geiser, P.A., Boyer, S.E.Construction of geological cross sections: techniques,assumptions andmethodsGeology, Penrose Conference Report, Vol. 17, No. 4, April pp. 373-375GlobalMapping, Geol. cross sections
DS200712-0716
2007
Geisler, T.Menneken, M., Nemchin, A.A., Geisler, T., Pidgeon, R.T., Wilde, S.A.Oldest terrestrial diamonds in zircon from Jack Hills, Western Australia.Plates, Plumes, and Paradigms, 1p. abstract p. A652.AustraliaJack Hills
DS200712-0717
2007
Geisler, T.Menneken, M., Newchin, A.A., Geisler, T., Pidgeon, R.T., Wilde, S.A.Hadean diamonds in zircon from Jack Hills, Western Australia.Nature, Vol. 448, August 23, pp. 917-921.Australia, Western AustraliaGeochronology
DS200812-0791
2008
Geisler, T.Nemchin, A.A., Whitehouse, M.J., Menneken, M., Geisler, T., Pidgeon, R.T., Wilde, S.A.A light carbon reservoir recorded in zircon hosted diamond from the Jack Hills.Nature, Vol. 454m, 7200, July 3, pp. 92-95.AustraliaGeochronology
DS200812-0897
2008
Geisler, T.Pidgeon, R.T., Nemchin, A.A., Geisler, T.Effects of chemical weathering on the chemical and isotopic signatures of ancient zircons from Jack Hills and Mt. Nattyer, western Australia.Goldschmidt Conference 2008, Abstract p.A747.AustraliaGeochronology
DS201012-0220
2010
Geissler, W.H.Geissler, W.H., Sodoudi, F., Kind, R.Thickness of the central and eastern European lithosphere as soon by S receiver functions.Geophysical Journal International, Vol. 181, 2, pp. 604-634.EuropeGeophysics - seismic
DS1990-1498
1990
Geissman, J.Van Schmus, W.R., Martin, M.W., Sprowl, D.R., Geissman, J.Age, neodymium and lead isotopic composition and magnetic polarity for subsurface samples of the 1100 Ma midcontinent riftGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A174GlobalGeochronology, Geophysics -magnetics
DS1989-0589
1989
Geissman, J.W.Harlan, S.S., Geissman, J.W., Snee, L.W., Schmidt, C.J.Paleomagnetism of Proterozoic mafic dikes, southwest Montana foreland, USANew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 121 Abstract held June 25-July 1MontanaPaleomagnetics, Dike
DS1996-0599
1996
Geissman, J.W.Harlan, S.S., Geissman, J.W., Snee, L.W., Reynolds, R.L.Late Cretaceous remagnetization of Proterozoic mafic dikes southern Highland Mountains southwest Montana -Ar40 Ar39Geological Society of America (GSA) Bulletin., Vol. 108, No. 6, June pp. 653-668.MontanaGeochronology, Paleomagnetics -Highland Mountains
DS1998-0476
1998
Geissman, J.W.Garza, R.S.M., Acton, G.D., Geissman, J.W.Carboniferous through Jurassic paleomagnetic dat a and their bearing on rotation of the Colorado Plateau.Journal of Geophysical Research, Vol. 103, No. B10, Oct. 10, pp. 24179-88.Colorado PlateauGeophysics - paleomagnetics, Tectonics
DS1994-0586
1994
Geist, E.L.Geist, E.L., Vallier, T.L., Scholl, D.W.Origin, transport, and emplacement of an exotic island arc terrane expose din eastern Kamchatka, Russia.Geological Society of America (GSA) Bulletin., Vol. 106, No. 9, Sept. pp. 1182-1994.RussiaTectonics, Paleomagnetism, Ophiolite
DS1970-0077
1970
Gelamkov, V.A.Fedynsky, V.V., Brodovoi, V.V., Gelamkov, V.A.Geophysics in Prospecting for Mineral Deposits in the UssrGeological Survey of Canada (GSC) Economic Geology Report, No. 26, PP. 667-687.Russia, YakutiaKimberlite, Geophysics
DS2002-0851
2002
Gelb, T.H.King, J.M., Shigley, J.E., Guhin, S.S., Gelb, T.H., Hall, M.Characterization and grading of natural colour pink diamondsGems & Gemology, Vol. 38, Summer, pp. 128-147.Australia, India, Brazil, South AfricaDiamonds - pink ( database of 1500 ), Notable - list ( more than 9 cts each)
DS2002-0852
2002
Gelb, T.H.King, J.M., Shigley, J.E., Guhin, S.S., Gelb, T.H., Hall, M.Box A: understanding the relationship of pink and "red" diamonds in GIA colour grading system.Gems & Gemology, Vol. 38, Summer, pp. 134-140.GlobalDiamonds - pink, red
DS200512-0532
2005
Gelb, T.H.King, J.M., Shigley, J.E., Gelb, T.H., Guhin, S.S., Hall, M., Wang, W.Characterization and grading of natural colour yellow diamonds.Gems & Gemology, Vol. 41, 2, Summer pp. 88-115.GlobalHistory, genesis, origin, cut
DS1995-1732
1995
Geldart, L.P.Sheriff, R.E., Geldart, L.P.Exploration seismology. Second editionCambridge University of Press, $ 130.00GlobalGeophysics -seismology, Book -ad
DS2000-0323
2000
Geldmacher, J.Geldmacher, J., Hoernle, K.The 72 Ma geochemical evolution of the Madeira hot spot ( eastern North Atlantic): recycling of Paleozoic....Earth and Planetary Science Letters, Vol.183, No.1-2, Nov.30, pp.73-92.MantleOceanic lithosphere, Geochemistry
DS200812-0392
2008
Geldmacher, J.Geldmacher, J., Hoernle, K., Lgel, 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.MantleGeophysics - EM
DS201806-1227
2018
Geldmacher, J.Homrighausen, S., Hoernle, K., Hauff, J., Geldmacher, J., Garbe-Schonberg, D.Global distribution of the HIMU end member: formation through Archean plume lid tectonics.Earth Science Reviews, Vol. 182, pp. 85-101.Globaltectonics

Abstract: Oceanic basalts reflect the heterogeneities in the earth's mantle, which can be explained by five mantle end members. The HIMU end member, characterized by high time-integrated ? (238U/204Pb), is defined by the composition of lavas from the ocean islands of St. Helena, South Atlantic Ocean and Mangaia and Tubuai (Cook-Austral Islands), South Pacific Ocean. It is widely considered to be derived from a mantle reservoir that is rarely sampled and not generally involved in mixing with the other mantle components. On the other hand, the FOZO end member, located at the FOcal ZOne of oceanic volcanic rock arrays on isotope diagrams, is considered to be a widespread common component with slightly less radiogenic 206Pb/204Pb and intermediate Sr-Nd-Hf isotopic compositions. Here we present new major and trace element, Sr-Nd-Pb-Hf isotope and geochronological data from the Walvis Ridge and Richardson Seamount in the South Atlantic Ocean and the Manihiki Plateau and Eastern Chatham Rise in the southwest Pacific Ocean. Our new data, combined with literature data, document a more widespread (nearly global) distribution of the HIMU end member than previously postulated. Our survey shows that HIMU is generally associated with low-volume alkaline, carbonatitic and/or kimberlitic intraplate volcanism, consistent with derivation from low degrees of melting of CO2-rich sources. The majority of end member HIMU locations can be directly related to hotspot settings. The restricted trace element and isotopic composition (St. Helena type HIMU), but near-global distribution, point to a deep-seated, widespread reservoir, which most likely formed in the Archean. In this context we re-evaluate the origin of a widespread HIMU reservoir in an Archean geodynamic setting. We point out that the classic ocean crust recycling model cannot be applied in a plume-lid dominated tectonic setting, and instead propose that delamination of carbonatite-metasomatized subcontinental lithospheric mantle could be a suitable HIMU source.
DS1989-0480
1989
Gelernter, D.Gelernter, D.The metamorphosis of information managementScientific American, Vol. 261, No. 2, August pp. 66-73. Database #18045GlobalOverview, Information processing
DS1990-0586
1990
Gelfand, R.B.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.
DS200412-0354
2004
Geli, L.Contrucci, I., Matias, L., Moulin, M., Geli, L., et al.Deep structure of the West African continental margin between 5S and 8S from reflection refraction seismics and gravity data.Geophysical Journal International, Vol. 158, 2, pp. 529-553.Africa, Democratic Republic of Congo, AngolaGeophysics - seismics
DS1960-1091
1969
Gellatly, D.C.Crohn, P.W., Gellatly, D.C.Probable Carbonatites in the Strangways Range Area, Centralaustralia.Aust. Journal of Science, Vol. 31, No. 9, PP. 335-336.Australia, Northern TerritoryKimberlite, Carbonatite
DS1960-1109
1969
Gellatly, D.C.Gellatly, D.C.Probable Carbonatites in the Strangways Range Area. Alcie Springs Sheet; Petrography and Geochemistry.B.m.r. Rec. Min. Res. Geol. Geophys., No. 1969/77, 38P. MAP SHEET SF 53/4.Australia, Northern TerritoryCarbonatite, Kimberlite
DS1970-0500
1972
Gellatly, D.C.Derrick, G.M., Gellatly, D.C.New Leucite Lamproites from West Kimberley, Western AustraliB.m.r. Min. Res. Bulletin., No. 125, PP. 103-119.Australia, Western AustraliaLeucite, Lamproite
DS1990-0529
1990
Geller, R.J.Geller, R.J.Metastable phases confirmedNature, Vol. 347, October 18, pp. 620-621GlobalMantle, Phases
DS1998-0484
1998
Geller, W.Geller, W., Klapper, H.Acidic mining lakesSpringer, 418p. $ 120.00EuropeBook - ad, Acid mine drainage
DS202011-2065
2020
Geller, Y.Vainer, S., Matmon, A., Erel, A.J., Hidy, A.J., Crouvi, O., De Wit, M., Geller, Y.Landscape responses to intraplate deformation in the Kalahari constrained by sediment provenance and chronology in the Okavango Basin.Basin Research, in press available Africa, South Africageomorphology

Abstract: The structural depression that occupies the Okavango Basin in southern Africa comprises a depo?centre within the intracratonic Kalahari Basin where sediments of the Cenozoic Kalahari Group have accumulated. The Okavango Basin has been formed due to stretching and subsidence at an area of diffused deformation, southwestwards to the main East African Rift System (EARS). Sediments from two full Kalahari Group sequences, located on opposite sides of the Gumare Fault that forms a major fault within the Okavango Basin, were studied to determine their provenance and chronology. Terrestrial Cosmogenic Nuclide (TCN) 26Al/10Be burial dating was used to constrain a chronostratigraphical framework, and Pb, Sr, and Nd isotopic ratios combined with geochemical and sedimentological analyses were applied to track the source areas of the sediments.Results indicate the following sequence of basin filling: (a) Accumulation between ca. 4-3 Ma during which the currently downthrown (southern) block received a mixture of sediments mostly from the Choma?Kalomo, Ghanzi?Chobe, and Damara terranes, and possibly from the Lufilian Belt and/or Karoo basalts during earlier stages of deposition. Simultaneously, the upthrown (northern) block received sediments from more distant Archean sources in the Zimbabwe and/or Kasai cratons, (b) Hiatus in sedimentation occurred at both sites between ca. 3-2 Ma, (c) Sediments on both sides of the Gumare Fault share a similar source (Angolan Shield) with minor distinct contributions to the downthrown block from the Kasai Craton and local sources input to the upthrown block, and (d) Regional distribution of aeolian sand since at least 1 Ma. The change in source areas is attributed to rearrangements of the drainage systems that were probably linked to vertical crustal movements on the margins of the Okavango Basin. The tectonically induced morphodynamics controlled the landscape evolution of the endorheic basin where vast lakes, wetlands and salt pans have developed through time.
DS2002-1053
2002
Gelman, M.Miller, E.L., Gelman, M., Parfenov, L., Hourigan, J.Tectonic setting of Mesozoic magmatism: a comparison between northeastern Russia and the North America Cordillera.Geological Society of America Special Paper, No. 360, pp. 313-32.Russia, AlaskaMagmatism, tectonics
DS1993-0495
1993
Gelman, M.L.Gelman, M.L.Effects of the alkalinity of transmagmatic fluids on the properties of magmatic seriesGeochemistry International, Vol. 30, No. 5, pp. 9-20RussiaMagma, Petrography
DS2003-0482
2003
Gelo, K.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
Gelo, K.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
DS1985-0221
1985
Gem And Jewellery Business IntelligenceGem And Jewellery Business IntelligenceDiamonds Discovered in ChinaGem And Jewellery Business Intelligence., MARCH 13.ChinaNews Item
DS1996-0492
1996
Gem and Jewllery NewsGem and Jewllery NewsThe golden jubilee diamond ....the largest diamond in the world..Gem Association Great Britain Quart Bulletin., Vol. 6, No. 1, 2p.South AfricaNews item, Diamond - Premier diamond
DS1981-0361
1981
Gem ex and min. ltd., CULTUS PACIFIC NL.Sas, Z., Gates, A.H., Gem ex and min. ltd., CULTUS PACIFIC NL.El 504, El 505, Mt. Christie, Muckanippie, Lake Barry (tarcoSouth Australia Open File., No. E3596, E3597, E3598, 186P. UNPUBL.Australia, South AustraliaGeochemistry, Stream Sediment Sampling, Heavy Minerals
DS1981-0362
1981
Gem ex and min. ltd., WESTERN QUEEN (SA).Sas, Z., Gates, A.H., Gem ex and min. ltd., WESTERN QUEEN (SA).El 760 Canegrass and El 763 Nilpinna, South Australia, Progress and Final Reports.South Australia Open File., No. E4061, 22P. UNPUBL.Australia, South AustraliaLiterature Review, Diamonds, Stratigraphy, Artesian Basin
DS1981-0178
1981
Gem Ex And Mins. LtdGem Ex And Mins. LtdAnnual Report to March 1982Gemex Spec. Publishing, AUGUST.Australia, Western Australia, South Australia, South AfricaEast Kimberleys, Argyle, Monastery Mine, Offshore Concessions
DS1970-0515
1972
Gem Exploration And Minerals LtdGem Exploration And Minerals LtdE.l. 460, Walcha AreaNew South Wales Geological Survey, GS 1972/259, (UNPUBL.).AustraliaKimberlite, Diamond
DS1982-0217
1982
Gem Exploration and Minerals Ltd., Northern Metals Pty. Ltd.Garlick, H.J., Gem Exploration and Minerals Ltd., Northern Metals Pty. Ltd.El 25890 Victoria River Nt. Annual Report for 1981Northern Territory Open File., No. CR 82-25, 19P. 5 MAPS. UNPUBL.Australia, Northern TerritoryGeochemistry, Prospecting, Diamonds, Stream Sediment Sampling
DS1982-0218
1982
Gem Exploration and Minerals Ltd., Northern Metals Pty. Ltd.Garlick, H.J., Gem Exploration and Minerals Ltd., Northern Metals Pty. Ltd.El 2580 Victoria River Area Nt Annual Report 1981Northern Territory Geological Survey Open File., No. CR 82/025, 19P.Australia, Northern TerritoryProspecting, Stream Sediment Sampling, Fitzroy
DS1981-0168
1981
Gem Exploration and Minerals Ltd., Suttons Moto.Garlick, H.J., Gem Exploration and Minerals Ltd., Suttons Moto.El 1965 Annual Report on ExplorationNorthern Territory Geological Survey Open File Report, No. CR 81/276, 21P.Australia, Northern TerritoryProspecting, Sampling, Geochemistry
DS2003-0447
2003
Gem Lab NotesGem Lab NotesCoated diamonds. New treatments. Brief 1 pg. overviewGems & Gemology, Vol. 39, Winter, p. 315.GlobalBlank
DS200412-0618
2003
Gem Lab NotesGem Lab NotesCoated diamonds. New treatments. Brief 1 pg. overview.Gems & Gemology, Vol. 39, Winter, p. 315.TechnologyDiamond morphology
DS201312-0299
2012
Gem Lab notesGem Lab notesPink diamonds with 478 nm peak - types ( example from Argyle).Gems & Gemology, Vol. 48, summer pp. 133-134.TechnologyDiamond morphology
DS201312-0300
2012
Gem Lab notesGem Lab notesRough diamonds with a green coating.Gems & Gemology, Vol. 48, summer p. 134.TechnologyDiamond morphology
DS201312-0301
2013
Gem Lab NotesGem Lab NotesCalcium fluoride coating found on 13 fancy pinks.Gems & Gemology, Lab notes p. 114.TechnologyDiamond - coating
DS201312-0302
2013
Gem Lab NotesGem Lab NotesStrong color zoning reflects complex growth environment… orangy brown type IAGems & Gemology, Lab notes p. 116.TechnologyDiamond - colour
DS201312-0303
2013
Gem Lab NotesGem Lab NotesVery large rough diamond 1,138 cts.Gems & Gemology, Lab notes pp. 116-117.Africa, Democratic Republic of CongoSpectroscopy
DS1989-0481
1989
Gem Lab. NotesGem Lab. NotesUnusual inclusions in diamondGems and Gemology, Vol. 25, No. 1, Spring p. 36GlobalDiamond morphology, Diamond inclusions
DS1989-0482
1989
Gem Lab. NotesGem Lab. NotesCoated diamonds again seen in the TradeGems and Gemology, Vol. 25, No. 1, Spring p. 36GlobalDiamond treatment-upgrade appearance, Coated diamonds
DS201906-1294
2019
Gem News InternationalGem News InternationalColombian emeralds and Mozambican rubies from Fura Gems….. Comments from Fura GemsGems & Gemology, Vol. 55, 1, pp. 125-126.South America, Columbiaemerald
DS201906-1295
2019
Gem News InternationalGem News InternationalPotentate's Montana sapphire mine: an interview with Warren Boyd.Gems & Gemology, Vol. 55, 1, pp. 134.United States, Montanasapphire

Abstract: The history of the American West is told in stories of frontiersmen seeking fortune in gold and other precious metals. It was serendipity when these intrepid adventurers arrived in western Montana and discovered strange, shiny pebbles—sapphires—while looking for gold. Little did they know the gem wealth they had uncovered with the sapphires, which were simply a nuisance to the gold miners at first. More than 100 years later, this legacy of mining is carried on by several small-scale miners across Montana, and with the arrival of Potentate Mining at the Rock Creek sapphire deposit. We had the chance to sit down in Tucson with Potentate’s director of marketing, Warren Boyd, for an update on their mining activities and their plans to find a place for Montana sapphires in the market...(No abstract - full article)
DS201709-1986
2017
Gem notesGem notesDiamond with concentric inclusionsGems & Gemology, p. 228.Technologydiamond inclusions
DS201810-2320
2018
Gem NotesGem NotesReduced phosphorescence of type II HPHT grown synthetic diamonds after electron beam irradiation.The Journal of Gemmology, Vol. 36, 3, pp. 208-210.Globalsynthetics
DS1993-0496
1993
Gem Trade Lab NotesGem Trade Lab NotesBrown-pink diamond with green grainingGems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 198-199.GlobalDiamond morphology, Colour
DS1993-0497
1993
Gem Trade Lab NotesGem Trade Lab NotesLight violet-gray diamondGems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 199.GlobalDiamond morphology, Colour
DS1993-0498
1993
Gem Trade Lab NotesGem Trade Lab NotesTreated green diamond with a blue colour zoneGems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 200.GlobalDiamond morphology, Colour
DS1993-0499
1993
Gem Trade Lab NotesGem Trade Lab NotesStrain phantom in diamondGems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 199.GlobalDiamond morphology, Crystal
DS1993-0500
1993
Gem Trade Lab NotesGem Trade Lab NotesSynthetic yellow diamond crystalGems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 200.GlobalDiamond morphology, Crystal
DS2001-0359
2001
Gem Trade Lab NotesGem Trade Lab NotesHeat treated black diamond before and afterGems and Gemology, Vol. 37, Fall, p. 214-15.GlobalDiamond - color enhanced
DS2001-0360
2001
Gem Trade Lab NotesGem Trade Lab NotesCarved Hamsa diamond... 11.4 ct sent in for identification reportGems and Gemology, Vol. 37, Fall, p. 214.GlobalDiamond - cutting
DS2001-0361
2001
Gem Trade Lab NotesGem Trade Lab NotesDiamond with pseudo-dichromismGems and Gemology, Gem trade lab notes, Vol. 37, spring, p. 59.GlobalDiamond - morphology
DS2001-0362
2001
Gem Trade Lab NotesGem Trade Lab NotesDiamond: with a hidden cloud formation ( darkfield and fibre-optic light source).Gems and Gemology, Gem trade lab notes, Vol. 37, spring, p. 59.GlobalDiamond - morphology
DS2001-0363
2001
Gem Trade Lab NotesGem Trade Lab NotesDiamond: synthetic diamond with distinctive surface featuresGems and Gemology, Gem trade lab notes, Vol. 37, spring, p. 60.GlobalDiamond - synthesis
DS2002-0513
2002
Gem Trade Lab NotesGem Trade Lab NotesDiamond - colour grade vs value for fancy coloursGems & Gemology, Vol.38,1, p.80., Vol.38,1, p.80.GlobalDiamond - fancy, economics, brief
DS2002-0514
2002
Gem Trade Lab NotesGem Trade Lab NotesDiamond - colour grade vs value for fancy coloursGems & Gemology, Vol.38,1, p.80., Vol.38,1, p.80.GlobalDiamond - fancy, economics, brief
DS2002-0515
2002
Gem Trade Lab NotesGem Trade Lab NotesDiamond examined with eclogitic inclusionsGems & Gemology, Vol.38,1, p.80-1., Vol.38,1, p.80-1.GlobalDiamond inclusions - brief
DS2002-0516
2002
Gem Trade Lab NotesGem Trade Lab NotesDiamond examined with eclogitic inclusionsGems & Gemology, Vol.38,1, p.80-1., Vol.38,1, p.80-1.GlobalDiamond inclusions - brief
DS2002-0517
2002
Gem Trade Lab NotesGem Trade Lab NotesDiamond - with internal inscriptions... laserGems and Gemology, Vol. 39, No. 4, winter p. 344.GlobalNews item, Diamond - inscriptions
DS2003-0448
2003
Gem Trade Lab NotesGem Trade Lab NotesIntensely coloured type IIa, with substantial nitrogen - related defectsGems & Gemology, Vol. 39, 1, Spring, p.39, 40.GlobalDiamond - nitrogen
DS2003-0449
2003
Gem Trade Lab NotesGem Trade Lab NotesDiamond with unusual overgrowthGems & Gemology, Vol. 39, 1, Spring, p.41.GlobalDiamond - regrowth
DS2003-0450
2003
Gem Trade Lab NotesGem Trade Lab NotesLifeGem synthetic diamondsGems & Gemology, Vol. 39, 1, Spring, p. 62.GlobalDiamond - synthetic
DS200412-0619
2003
Gem Trade Lab NotesGem Trade Lab NotesLifeGem synthetic diamonds.Gems & Gemology, Vol. 39, 1, Spring, p. 62.TechnologyDiamond - synthetic
DS200412-0620
2003
Gem Trade Lab NotesGem Trade Lab NotesDiamond with unusual overgrowth.Gems & Gemology, Vol. 39, 1, Spring, p.41.TechnologyDiamond - regrowth
DS200412-0621
2003
Gem Trade Lab NotesGem Trade Lab NotesIntensely coloured type IIa, with substantial nitrogen - related defects.Gems & Gemology, Vol. 39, 1, Spring, p.39,40.TechnologyDiamond - nitrogen
DS200812-1078
2008
Gembitckaya, I.M.Skublov, S.G., Lobach Zhuchenko, S.B., Guseva, N.S., Gembitckaya, I.M., Tolmacheva, E.V.REE distribution in zircons from lamproites in Panozero complex of sanukitoids (Karelia, NW Russia).Goldschmidt Conference 2008, Abstract p.A875.Russia, KareliaLamproite
DS200912-0697
2009
Gembitskaya, I.M.Skublov, S.G., Lobach-Zhuchenko, S.B., Guseva, N.S., Gembitskaya, I.M., Tolmacheva, E.V.Rare earth and trace element distribution in zircons from miaskite lamproites of the Panozero complex, central Karelia.Geochemistry International, Vol. 47, 9., Sept. pp. 901-913.RussiaLamproite
DS1991-1274
1991
Gemeke, D.A.Otter, M.L., Gemeke, D.A., Harte, B., Gurney, J.J., Harris, J.W.Diamond growth histories revealed by cathodluminescence and carbon isotopestudiesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 318-319Southern AfricaPremier, Bultfontein, Finsch, Koffiefontein, Geochronology
DS1991-0657
1991
Gemerts, G.Handelsman, S.D., Gemerts, G.Conference report on United Nations inter regional seminar on computerized mineral title management and associated databasesNatural Resources forum, August pp. 235-238GlobalDatabases, Economics -mineral titles
DS1980-0140
1980
Gemex And Mins. LtdGemex And Mins. LtdInformation to Shareholders on Current ActivitiesGemex Annual Report For 1979, PP. 5-19.Australia, Western Australia, South Australia, South AfricaWest Kimberley, Central Kimberley, East Kimberley, Ord River
DS1940-0150
1947
Gemme, P.Gemme, P.Le Diamant dans le MondeBruxelles: Collection Nationale Office De Publicite, S.c., GlobalHistory
DS2002-0803
2002
GemmellKamenetsky, V.S., Davidson, Mernagh, Crawford, GemmellFluid bubbles in melt inclusions and pillow rim glasses: high temperature precursors to hydrothermal..Chemical Geology, Vol.183, 1-4, pp.349-64.MantleMelt - inclusions, Geochemistry
DS2002-0518
2002
GemocGemocStructure and chemistry of the Australian lithosphereGemoc 2001 Annual Report, p.35AustraliaGeochemistry - garnet, Research project - brief highlight
DS2002-0519
2002
GemocGemocAncient mantle beneath New EnglandGemoc 2001 Annual Report, p.32-3.AustraliaGeochemistry, mineralogy, inclusions, Research project - brief highlight
DS2002-0520
2002
GemocGemocWandering poles in the Late CambrianGemoc 2001 Annual Report, p.34.AustraliaPaleomagnetism, Research project - brief highlight
DS2002-0521
2002
GemocGemocMantle mixup beneath TasmaniaGemoc 2001 Annual Report, p.38.Australia, TasmaniaTectonics, geochronology, Research project - brief highlight
DS2002-0522
2002
GemocGemocCooking mantle fluids - trace element mobility during subductionGemoc 2001 Annual Report, p.40-1.MantleGeochemistry, Research project - brief highlight
DS2002-0523
2002
GemocGemocSulphides - more evidence for plumes from the lower mantle?Gemoc 2001 Annual Report, pp. 24-5.Mantle, Russia, SiberiaGeochemistry, mineralogy, sulphides, Research project - brief highlight
DS2002-0524
2002
GemocGemocMicrodiamonds and microminerals Slave Craton, CanadaGemoc 2001 Annual Report, p.29.Northwest TerritoriesGeochemistry, mineralogy, inclusions, Research project - brief highlight
DS2002-0525
2002
GemocGemocMapping the mantle with garnet variables - order from complexityGemoc 2001 Annual Report, pp. 20-21.Northwest Territories, Southern Africa, Russia, SiberiaGeochemistry, mineralogy, Research project - brief highlight
DS2002-0526
2002
GemocGemocArchean mantle hiding under Proterozoic crust in western NorwayGemoc 2001 Annual Report, p.31,2.NorwayGeochemistry, mineralogy, inclusions, Research project - brief highlight
DS2002-0527
2002
GemocGemocHafnium isotopes and the Baltic margin jigsaw puzzleGemoc 2001 Annual Report, p.36-7.Norway, Baltic ShieldTectonics, geochronology, Research project - brief highlight
DS2002-0528
2002
GemocGemocHow old are diamonds?Gemoc 2001 Annual Report, p.28.Russia, SiberiaGeochemistry, mineralogy, inclusions, Research project - brief highlight
DS2002-0529
2002
GemocGemocGreen and gold sulphides in olivine date the Siberian lithosphereGemoc 2001 Annual Report, p.30.Russia, SiberiaGeochemistry, mineralogy, inclusions, Research project - brief highlight
DS2002-0530
2002
GemocGemocGeochemical remote sensing of the deep Earth - 4D lithospheric mapping 2001Gemoc 2001 Annual Report, pp. 18-19.Siberia, Russia, mantleGeochemistry, lithosphere, Research project - brief highlight
DS2002-0531
2002
GemocGemocChemical tomography beneath the Kalahari CratonGemoc 2001 Annual Report, pp. 22-3.South AfricaGeochemistry, mineralogy, garnet, Research project - brief highlight
DS2002-0532
2002
GemocGemocPlateaus, plumes and fluids in Kerguelen xenolithsGemoc 2001 Annual Report, p.39.South Indian Ocean, Kerguelen IslandsGeochemistry, Research project - brief highlight
DS2002-0533
2002
Gemoc Annual ReportGemoc Annual ReportNot so stable after all? High temperature deformation induces resetting in zirconGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 22-23.AntarcticaBlank
DS2002-0534
2002
Gemoc Annual ReportGemoc Annual ReportWaves of fluid invade the mantle beneath western VictoriaGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 34-5.AustraliaBlank
DS2002-0535
2002
Gemoc Annual ReportGemoc Annual ReportLower crustal terranes in the North Chin a craton - new surprises from xenolithsGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 28-9.ChinaBlank
DS2002-0536
2002
Gemoc Annual ReportGemoc Annual ReportTrace elements in mantle rocks revisited - a warning to modellersGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 40-41.Colorado PlateauBlank
DS2002-0537
2002
Gemoc Annual ReportGemoc Annual ReportTrace element partitioning - time for the detailGemoc Arc National Key Centre For The Geochemical Evolution And, p. 41.GlobalBlank
DS2002-0538
2002
Gemoc Annual ReportGemoc Annual ReportFingerprinting diamond. Studying trace elementsGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 26-7.GlobalBlank
DS2002-0539
2002
Gemoc Annual ReportGemoc Annual ReportHafnium in rutile frees Slave secretsGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 31-2.Northwest TerritoriesDeposit - Lac de Gras
DS2002-0540
2002
Gemoc Annual ReportGemoc Annual ReportLithospheric mapping beneath the North American plateGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 18-19.Northwest Territories, Colorado, SaskatchewanBlank
DS2002-0541
2002
Gemoc Annual ReportGemoc Annual ReportFrom dunite to lherzolite: tracking refertilization of Archean peridotite in NorwayGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 24-5.NorwayBlank
DS2002-0542
2002
Gemoc Annual ReportGemoc Annual ReportMg isotopes in olivine track fluid flow in the mantleGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 38-9.Russia, South Africa, Northwest Territories, AustraliaBlank
DS2002-0543
2002
Gemoc Annual ReportGemoc Annual ReportTaking the pulse of the Earth: lithospheric events tracked in situ geochronologyGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 20-21.South Africa, Western terraneBlank
DS2002-0544
2002
Gemoc Annual ReportGemoc Annual ReportMantle composition and processes beneath the Taiwan Strait, SE AsiaGemoc Arc National Key Centre For The Geochemical Evolution And, pp. 33-4.TaiwanBlank
DS200412-0622
2004
Gemoc Annual ReportGemoc Annual ReportGarnets key to SCLM ( Subcontinental lithospheric mantle)GEMOC Annual Report, pp. 17-19.Mantle, AustraliaNews item - Petrology, geophysics lithospheric mantle
DS200412-0623
2004
Gemoc Annual ReportGemoc Annual ReportThe upper crust sheds some crumbs: a top down perspective of the Slave Craton.GEMOC Annual Report, pp. 28-29.Canada, Northwest TerritoriesNews item - Geochronology, tectonics
DS200412-0624
2004
Gemoc Annual ReportGemoc Annual ReportArchean mantle betrays Norway's lithospheric age.GEMOC Annual Report, p. 30.Europe, NorwayNews item - geochronology
DS200412-0625
2004
Gemoc Annual ReportGemoc Annual ReportArchean mantle betrays Norway's lithospheric age.GEMOC Annual Report, pp. 34-5.Canada, Northwest Territories, SaskatchewanNews item - geochronology
DS200412-0626
2004
Gemoc Annual ReportGemoc Annual ReportTerraneChron*: a competitive edge in exploration and understanding crustal evolution.GEMOC Annual Report, pp. 39-40.MantleNews item - geochronology
DS200412-0627
2004
Gemoc Annual ReportGemoc Annual ReportThe deviant Archean....Tectonic processesGEMOC Annual Report, pp. 20-23.Mantle, AustraliaNews item - Geothermometry, tectonics
DS200412-0628
2004
Gemoc Annual ReportGemoc Annual ReportCarbonatites beneath oceanic plateaus: trapped melts in xenoliths from Kerguelen.GEMOC Annual Report, pp. 40-41.Indian OceanNews item - geochronology
DS200412-0629
2004
Gemoc Annual ReportGemoc Annual ReportThe old SOAK - Hf in MARID rutile unravels mantle metasomatism.GEMOC Annual Report, pp. 36-37.MantleNews item - metasomatism
DS200412-0630
2002
Gemoc Annual ReportGemoc Annual ReportLithospheric mapping beneath the North American plate.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 18-19.Canada, Northwest Territories, Saskatchewan, United States, ColoradoStructure, tectonics
DS200412-0631
2002
Gemoc Annual ReportGemoc Annual ReportTaking the pulse of the Earth: lithospheric events tracked in situ geochronology.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 20-21.Africa, South AfricaStructure, tectonics
DS200412-0632
2002
Gemoc Annual ReportGemoc Annual ReportTrace elements in mantle rocks revisited - a warning to modellers.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 40-41.United States, ColoradoMineral chemistry
DS200412-0633
2002
Gemoc Annual ReportGemoc Annual ReportMg isotopes in olivine track fluid flow in the mantle.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 38-9.Russia, Africa, South Africa, Canada, Northwest Territories, AustraliaSpectrometry
DS200412-0634
2002
Gemoc Annual ReportGemoc Annual ReportMantle composition and processes beneath the Taiwan Strait, SE Asia.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 33-4.TaiwanXenoliths
DS200412-0635
2002
Gemoc Annual ReportGemoc Annual ReportTrace element partitioning - time for the detail.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, p. 41.TechnologyMineral chemistry
DS200412-0636
2002
Gemoc Annual ReportGemoc Annual ReportFrom dunite to lherzolite: tracking refertilization of Archean peridotite in Norway.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 24-5.Europe, NorwayWestern Gneiss Region - garnet peridotites
DS200412-0637
2002
Gemoc Annual ReportGemoc Annual ReportLower crustal terranes in the North Chin a craton - new surprises from xenoliths.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 28-9.ChinaGeochronology
DS200412-0638
2002
Gemoc Annual ReportGemoc Annual ReportHafnium in rutile frees Slave secrets.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 31-2.Canada, Northwest TerritoriesEclogite xenoliths Deposit - Lac de Gras
DS200412-0639
2002
Gemoc Annual ReportGemoc Annual ReportWaves of fluid invade the mantle beneath western Victoria.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 34-5.AustraliaMetasomatism, clinopyroxene
DS200412-0640
2002
Gemoc Annual ReportGemoc Annual ReportNot so stable after all? High temperature deformation induces resetting in zircon.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 22-23.AntarcticaGeochronology
DS200412-0641
2002
Gemoc Annual ReportGemoc Annual ReportFingerprinting diamond. Studying trace elements.GEMOC ARC National Key Centre for the Geochemical Evolution and Metallogeny of Continents, pp. 26-7.GlobalDiamond morphology
DS1996-0507
1996
Gemological AbstractsGems and Gemology, Gemological Abstracts1995 record year for diamond imports, exports. abstract of NationalJeweler, April 1, 1996 p. 76.Gems and Gemology, Summer, p. 144.GlobalDiamond exports
DS1996-0508
1996
Gemological AbstractsGems and Gemology, Gemological AbstractsDiscard small diamonds - they're not worth the effort. Abstract Diamond Industry Week, Vol. 2, 39 Oct 9, '95 p4Gems and Gemology, Summer, p. 144.GlobalDiamond prices
DS2002-0545
2002
Gemological AbstractsGemological AbstractsThe discreet tycoon. by R. Weldon. reviewed in Professional Jeweler, Vol. 5, 1, 2002, pp. 20,21, 22, 26. Lev Leviev's Angolan connection. 5, 2, pp.19-21.Gems and Gemology, Vol. 38, Fall, p. 290 ( 1p. abstract)AngolaNews item - Leviev background
DS2002-0546
2002
Gemological AbstractsGemological AbstractsChanging diamond colour. Gemological Bulletin, (Russia) No. 3, pp. 19-30. 2001Gems and Gemology, Vol. 38, Fall, p. 288 ( 1p. abstract)RussiaDiamond - treatment
DS1994-0587
1994
Gemological Institute of America (GIA)Gemological Institute of America (GIA)The Gemological Institute of America (GIA) diamond dictionaryGemological Institute of America (GIA) Bookstore, 3rd. edition, $ 115.00GlobalDiamond dictionary, Diamond history, jewellers
DS2001-0364
2001
Gemological Institute of America (GIA)Gemological Institute of America (GIA)New video offers rare behind the scenes look at diamond gradingGemological Institute of America (GIA)., Sept. 5, 1p.GlobalNews item - press release, Gemological Institute of America (GIA) laboratory
DS1997-0375
1997
Gemological Institute of America (GIA) Lab NotesGemological Institute of America (GIA) Lab NotesDiamond with " additional color".... rough with contrasting colorsGems and Gemology, Vol. 33, Summer pp. 134-136.GlobalDiamond - color
DS1998-0485
1998
Gemological Institute of America (GIA) Lab NotesGemological Institute of America (GIA) Lab NotesDiamond - color treated from orangy yellow to reddish purple....examination of before and after radiation.Gems and Gemology, Fall pp. 213-4.GlobalDiamond - irradiation
DS1998-0486
1998
Gemological Institute of America (GIA) Lab NotesGemological Institute of America (GIA) Lab NotesRaman analysis of inclusions..Gems and Gemology, Fall p. 214.GlobalDiamond morphology - inclusions
DS2000-0324
2000
Gemological Institute of America (GIA) Lab NotesGemological Institute of America (GIA) Lab NotesBlue and pink, HPHT annealed. 11 diamonds examined for colour properties.GE POL diamonds from Bellataire.Gems and Gemology., Vol. 36, Fall, p. 254-5.GlobalDiamond - enhancement, colour change
DS2000-0325
2000
Gemological Institute of America (GIA) Lab NotesGemological Institute of America (GIA) Lab NotesTwo diamonds examined - with flower like inclusionsGems and Gemology., Vol. 36, Fall, p. 255.GlobalDiamond - morphology
DS2000-0326
2000
Gemological Institute of America (GIA) Lab NotesGemological Institute of America (GIA) Lab NotesSynthetic moissanite: a black diamond substituteGems and Gemology., Vol. 36, Fall, p. 256.GlobalMoissanite
DS2000-0588
2000
Gemological Institute of America (GIA) World NewsLoupe,Gemological Institute of America (GIA) World NewsUpdate on the new incolour treated black and green diamondsThe Loupe,Gemological Institute of America (GIA) World News, Vol. 9, No. 9, Fall, pp. 16-18.GlobalDiamond morphology - colour, Technology
DS2002-0547
2002
GemprintGemprintGemprint (TM) the fingerprinting system for diamonds supports major brandingGemprint, Oct. 10, 1p.ItalyNews item - press release
DS1985-0222
1985
Gems & GemologyGems & GemologyChangma Diamond Deposit Very ActiveGems and Gemology, Vol. 21, Winter p. 247ChinaNews Item
DS1985-0223
1985
Gems & GemologyGems & GemologyPiggyback Diamond - Cutting of StoneGems and Gemology, Vol. 21, Winter p. 234GlobalDiamond Cutting, News Item
DS1985-0224
1985
Gems & GemologyGems & GemologyHeat Induced Colour Change in DiamondGems and Gemology, Vol. 21, Winter p. 232GlobalDiamond Morphology
DS1985-0225
1985
Gems & GemologyGems & GemologyDiamond With Natural Internal Irradiation StrainGems and Gemology, Vol. 21, Winter p. 233GlobalDiamond Morphology
DS1985-0226
1985
Gems & GemologyGems & GemologyDiamond Futures Market PlannedGems and Gemology, Vol. 21, Winter p. 247GlobalEconomics, News Item
DS1985-0227
1985
Gems & GemologyGems & GemologyDiamond for High Rollers. ( a Faceted Diamond die from a Large Industrial Diamond).Gems And Gemology, Vol. 21, FALL GEM TRADE LAB NOTES P. 172.GlobalBlank
DS1985-0228
1985
Gems & GemologyGems & GemologyAlluvial Diamond DepositsGems and Gemology, Vol. 21, Winter p. 247IndiaNews Item
DS1986-0274
1986
Gems & GemologyGems & GemologyThe magic of minerals - book reviewGems and Gemology, Vol. XXIII Winter p. 243GlobalBook Review
DS1986-0275
1986
Gems & GemologyGems & GemologyDescriptions of Gem materialsGems and Gemology, Vol. XXIII Winter p. 244GlobalBook Review
DS1986-0276
1986
Gems & GemologyGems & GemologyNatural color light green diamondsGems and Gemology, Vol. XXII Fall, p. 171GlobalDiamond, Colour
DS1986-0277
1986
Gems & GemologyGems & GemologyUnusual inclusion in diamondGems and Gemology, Vol. XXII Fall, p. 172GlobalDiamond, Inclusions
DS1986-0278
1986
Gems & GemologyGems & GemologySaint Valentines diamondGems and Gemology, Vol. XXIII Winter p. 236GlobalDiamond, Notable
DS1986-0279
1986
Gems & GemologyGems & GemologyThe Portuguese diamondGems and Gemology, Vol. 22, No. 2, Summer, pp. 100-101GlobalDiamonds notable
DS1986-0280
1986
Gems & GemologyGems & GemologyThe Marie Antoinette earringsGems and Gemology, Vol. 22, No. 2, Summer, pp. 101-102GlobalDiamonds notable
DS1986-0281
1986
Gems & GemologyGems & GemologyDiamond alphabetGems and Gemology, Vol. 22, No. 1, Spring, p. 47GlobalNews item
DS1987-0242
1987
Gems & GemologyGems & GemologyLargest California diamond foundGems and Gemology, Vol. 23, No. 2, Summer pp. 122-123California, TrinityNews item Photograph- brief text, 14.33 carat rough
DS1987-0243
1987
Gems & GemologyGems & GemologySynthetic diamondGems and Gemology, Vol. 23, No. 2, Summer p. 44GlobalDiamond synthesis
DS1987-0244
1987
Gems & GemologyGems & GemologyDiamond: highly radioactive green diamondGems and Gemology, Vol. 23, Fall, pp. 164-165GlobalBlank
DS1988-0242
1988
Gems & GemologyGems & GemologyMysteriously damaged.. diamond.. flaws and recent damage to stonesGems and Gemology, Vol. 24, No. 4, Winter p. 242GlobalDiamond cutting
DS1988-0243
1988
Gems & GemologyGems & GemologyA historical note: highlights of gem trade... fancy cut diamonds, laser drill holes, dendritic diamondmountedGems and Gemology, Vol. 24, No. 4, Winter p. 246-247GlobalDiamond cutting
DS1988-0244
1988
Gems & GemologyGems & GemologyDiamond- imitation crystalGems and Gemology, Vol. 24, No. 4, Winter p. 241GlobalDiamond synthesis
DS1989-0483
1989
Gems & GemologyGems & GemologyJoint venture with De Beers in AustraliaGems and Gemology, Vol. 25, No. 3, p. 178AustraliaNews item, Max Resources, Skull Creek
DS1989-0484
1989
Gems & GemologyGems & GemologyDiamond cutting in ChinaGems and Gemology, Vol. 25, No. 3, p. 177ChinaNews item, Diamond cutting
DS1989-0485
1989
Gems & GemologyGems & GemologyDiamond with a concave table facetGems and Gemology, Vol. 25, No. 3, p. 171-172GlobalDiamond cutting
DS1989-0486
1989
Gems & GemologyGems & GemologyDiamond -engraved faceted tabletGems and Gemology, Vol. 25, No. 3, p. 172-173GlobalDiamond cutting
DS1989-0487
1989
Gems & GemologyGems & GemologyDiamond cube with cloud like inclusion. *Gem trade Lab notes sectionGems and Gemology, Vol. 25, No. 2, Summer p. 102GlobalDiamond morphology
DS1989-0488
1989
Gems & GemologyGems & GemologyFancy intense yellow diamond with a green irradiationstain.*Gem trade Lab notes sectionGems and Gemology, Vol. 25, No. 2, Summer p. 102-3GlobalDiamond morphology, Irradiation
DS1989-0489
1989
Gems & GemologyGems & GemologyNaturally irradiated diamond rough. *Gem trade Lab notes sectionGems and Gemology, Vol. 25, No. 2, Summer p. 102-3GlobalDiamond morphology, Irradiation
DS1989-0490
1989
Gems & GemologyGems & GemologyRecent advances in gem diamond synthesisGems and Gemology, Vol. 25, No. 1, Spring p. 50GlobalDiamond synthesis
DS1989-0491
1989
Gems & GemologyGems & GemologySynthetic diamond vs. cubic zirconiaGems and Gemology, Vol. 25, No. 1, Spring p. 50GlobalDiamond synthesis
DS1989-0492
1989
Gems & GemologyGems & GemologySynthetic diamonds by detonationGems and Gemology, Vol. 25, No. 1, Spring p. 50GlobalDiamond synthesis
DS1989-0493
1989
Gems & GemologyGems & GemologyDiamond - increases in diamond salesGems and Gemology, Vol. 25, No. 3, p. 177GlobalNews item, Economics
DS1989-0494
1989
Gems & GemologyGems & GemologyCoated diamond. *Gem trade Lab notes sectionGems and Gemology, Vol. 25, No. 2, Summer p. 102GlobalPink diamond, Coated diamond
DS1989-0495
1989
Gems & GemologyGems & GemologyStrained relations between India and AustraliaGems and Gemology, Vol. 25, No. 3, p. 177India, AustraliaNews item, Diamond cutting
DS1989-0496
1989
Gems & GemologyGems & GemologyImitations from Africa - fake diamond octahedra( synthetic cubiczirconia)Gems and Gemology, Vol. 25, No. 1, Spring p. 50NamibiaDiamond synthesis
DS1989-0497
1989
Gems & GemologyGems & GemologyTests under way for diamonds in Canada. CoronaGems and Gemology, Vol. 25, No. 3, p. 177SaskatchewanNews item, Corona
DS1989-0498
1989
Gems & GemologyGems & GemologyNew De Beers mine in NamibiaGems and Gemology, Vol. 25, No. 3, p. 178Southwest Africa, NamibiaNews item, CDM.
DS1989-0499
1989
Gems & GemologyGems & GemologyAustralians explore for diamonds in the United StatesGems and Gemology, Vol. 25, No. 3, p. 178Wisconsin, MichiganNews item, Dow, Crystal, Karonic Prosp
DS1990-0530
1990
Gems & GemologyGems & GemologyNew area in Angola to be minedGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 159AngolaNews item, Exploration news
DS1990-0531
1990
Gems & GemologyGems & GemologyDiamond rush in Australia. Extracted from Diamond Intelligence Briefs June8, 1990 which reviewed a report by Min-Met Information ServicesGems and Gemology, Gem News, Vol. 26, No. 3, Fall pp. 229AustraliaNews item, Diamond companies activities
DS1990-0532
1990
Gems & GemologyGems & GemologyBotswana bears targetGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 159BotswanaNews item, Diamond production
DS1990-0533
1990
Gems & GemologyGems & GemologyProspecting in BotswanaGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 160BotswanaNews item, Molopo Australia
DS1990-0534
1990
Gems & GemologyGems & GemologyArgyle cutting school near BeijingGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 159ChinaNews item, Diamond cutting
DS1990-0535
1990
Gems & GemologyGems & GemologyTreated green diamondGems and Gemology, Vol. 26, Winter pp. 296GlobalColour enhancement, Green diamond
DS1990-0536
1990
Gems & GemologyGems & GemologyFancy black diamond and conductivityGems and Gemology, Gem trade lab notes, Vol. 26, No. 3, Fall pp. 221GlobalDiamond morphology, Conductivity
DS1990-0537
1990
Gems & GemologyGems & GemologyElectron irradiated diamondGems and Gemology, Gem trade lab notes, Vol. 26, No. 3, Fall pp. 220-221GlobalDiamond morphology, Irradiation
DS1990-0538
1990
Gems & GemologyGems & GemologyLaser drill hole anomaly -diamondsGems and Gemology, Gem trade lab notes, Vol. 26, No. 3, Fall pp. 221GlobalDiamond morphology, Laser drills
DS1990-0539
1990
Gems & GemologyGems & GemologyLaser drilled to reach an included diamond crystalGems and Gemology, Gem trade lab notes, Vol. 26, No. 3, Fall pp. 222GlobalDiamond morphology, Laser drills
DS1990-0540
1990
Gems & GemologyGems & GemologyEtch channels in diamondGems and Gemology, Vol. 26, No. 2, Summer, p. 154GlobalGem trade lab notes, Mineralogy -diamond
DS1990-0541
1990
Gems & GemologyGems & GemologyAnother purple diamondGems and Gemology, Vol. 26, No. 2, Summer, p. 154GlobalGem trade lab notes, Mineralogy -purple diamon
DS1990-0542
1990
Gems & GemologyGems & GemologyMalaysia diamond plantGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 159GlobalNews item, Mineral processing
DS1990-0543
1990
Gems & GemologyGems & GemologyScientists research material as hard as diamondGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 159GlobalNews item, Synthetic diamond like
DS1990-0544
1990
Gems & GemologyGems & GemologyCubic zirconia -simulating a fancy yellow diamondGems and Gemology, Vol. 26, Winter pp. 295GlobalSpectroscopy, Yellow diamond
DS1990-0545
1990
Gems & GemologyGems & GemologyFancy intense yellowGems and Gemology, Vol. 26, Winter pp. 295-296GlobalSpectroscopy, Yellow diamond
DS1990-0546
1990
Gems & GemologyGems & GemologyDiamond prospecting in India. Brief extract from Diamond World May-June1990Gems and Gemology, Gem News, Vol. 26, No. 3, Fall pp. 228IndiaNews item, Diamond prospecting
DS1990-0547
1990
Gems & GemologyGems & GemologyKimberlite find in the U.SGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 159MichiganNews item, Crystal Exploration
DS1990-0548
1990
Gems & GemologyGems & GemologyDiamond cutting industry in Sri LankaGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 160Sri LankaNews item, Diamond cutting
DS1990-0549
1990
Gems & GemologyGems & GemologyTanzania intensifies mineral searchGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 160TanzaniaNews item, Diamond exploration
DS1990-0550
1990
Gems & GemologyGems & GemologySoviet-Singapore joint ventureGems and Gemology, Gem news, Vol. 26, No. 2, Summer, p. 159RussiaNews item, Almaz
DS1991-0543
1991
Gems & GemologyGems & GemologyArgyle set to expand with mining at homeGems and Gemology, Vol. XXVII, Fall, p. 180AustraliaNews item, Argyle
DS1991-0544
1991
Gems & GemologyGems & GemologyDiamonds and cutting in ChinaGems and Gemology, Vol. XXVII, Fall, p. 180ChinaNews item, Argyle
DS1991-0545
1991
Gems & GemologyGems & GemologyDiamond with hexagonal indented natural depressionsGems and Gemology, Vol. XXVII, Fall, p. 174GlobalGem lab notes, Diamond morphology
DS1991-0546
1991
Gems & GemologyGems & GemologyType IIb with natural irradiation stainsGems and Gemology, Vol. XXVII, Fall, p. 174-175GlobalGem lab notes, Diamond morphology
DS1991-0547
1991
Gems & GemologyGems & GemologyNew diamond cutsGems and Gemology, Vol. XXVII, Fall, p. 181GlobalNews item, Diamond cutting
DS1991-0548
1991
Gems & GemologyGems & GemologyHistorical diamond photographsGems and Gemology, Vol. XXVII, Fall, p. 181GlobalNews item, Photographs-history
DS1991-0549
1991
Gems & GemologyGems & GemologyAdditional diamonds discovered at Fort a la Corne, Saskatchewan CanadaGems and Gemology, Vol. XXVII, Fall, p. 180SaskatchewanNews item, Uranertz
DS1991-0550
1991
Gems & GemologyGems & GemologyDiamonds .. amid warnings of large scale theftGems and Gemology, Vol. XXVII, Fall, p. 180South AfricaNews item, CDM.
DS1991-0551
1991
Gems & GemologyGems & GemologyOperations re-established at Elizabeth BayGems and Gemology, Vol. XXVII, Fall, p. 180South AfricaNews item, CDM.
DS1991-0552
1991
Gems & GemologyGems & GemologyNew Soviet diamond sourceGems and Gemology, Vol. XXVII, Fall, p. 180RussiaNews item, Buryatskaya
DS1992-0520
1992
Gems & GemologyGems & GemologyAn X-ray study of some Argyle diamonds. extract from Industrial DiamondReviewGems and Gemology, 28, No. 4, Winter p. 282AustraliaNews item, Argyle
DS1992-0521
1992
Gems & GemologyGems & GemologyExpansion at JwanengGems and Gemology Gem News section, Vol. 28, Fall, p. 198BotswanaNews item, Production expansion
DS1992-0522
1992
Gems & GemologyGems & GemologyDiamond center planned for ChinaRapaport Diamond Report, January 11, 1991 p. 8, Gems and Gemology, Vol. 27, No. 4, pp. 254ChinaNews item, Diamond manufacturing
DS1992-0523
1992
Gems & GemologyGems & GemologyZaire tightens trade regulationsGems and Gemology, Vol. 28, No. 2, Summer pp. 131Democratic Republic of CongoNews item, Legal
DS1992-0524
1992
Gems & GemologyGems & GemologyZaire produced fewer diamondsGems and Gemology, Vol. 28, No. 2, Summer pp. 131Democratic Republic of CongoNews item, Production
DS1992-0525
1992
Gems & GemologyGems & GemologyDiamond - with aggregate crystallizationGems and Gemology, Gem trade lab notes, Vol. 28, Spring pp. 52GlobalDiamond crystallography, Morphology
DS1992-0526
1992
Gems & GemologyGems & GemologyTreated color diamonds with natural radiation stainsGems and Gemology, Diamond laboratory Notes, Vol. 27, No. 4, pp. 249GlobalDiamond morphology, Diamond colour
DS1992-0527
1992
Gems & GemologyGems & GemologyGreen, with natural surface colorGems and Gemology, Gem trade lab notes, Vol. 28, Spring pp. 53-54GlobalDiamond, Diamond morphology -color
DS1992-0528
1992
Gems & GemologyGems & GemologyBlack dice and gray with crossesGems and Gemology, Gem trade lab notes, Vol. 28, Spring pp. 53GlobalDiamond, Morphology
DS1992-0529
1992
Gems & GemologyGems & GemologyFire damaged diamondGems and Gemology, Gem trade lab notes, Vol. 28, Spring pp. 53GlobalDiamond, Morphology
DS1992-0530
1992
Gems & GemologyGems & GemologyDiamond cutting plant in VietnaMGems and Gemology Gem News section, Vol. 28, Fall, p. 199GlobalNews item, Cutting plant
DS1992-0531
1992
Gems & GemologyGems & GemologyThe lure of diamonds... extract from Newsweek November 9, 1992 pp. 34-35Gems and Gemology, 28, No. 4, Winter p. 281GlobalNews item, Diamond production
DS1992-0532
1992
Gems & GemologyGems & GemologyDiamonds from MyanmarGems and Gemology Gem News section, Vol. 28, Fall, p. 198GlobalNews item, Diamonds
DS1992-0533
1992
Gems & GemologyGems & GemologyBritish Crown Jewels to move to ground floor premises of the Tower ofLondonGems and Gemology Gem News section, Vol. 28, Fall, p. 198GlobalNews item, Interest
DS1992-0534
1992
Gems & GemologyGems & GemologyGem news on white opalescent diamonds from Panna mine in India at Tucsongem showGems and Gemology, Gem news, Vol. 28, Spring p. 58IndiaNews item, Diamond morphology -color
DS1992-0535
1992
Gems & GemologyGems & GemologyIndian plans increased miningGems and Gemology Gem News section, Vol. 28, Fall, p. 198IndiaNews item, Production
DS1992-0536
1992
Gems & GemologyGems & GemologyResults of Canadian bulk sampling.. extract from Mining Journal July 3, 1992 p. 4Gems and Gemology Gem News section, Vol. 28, Fall, p. 198Northwest TerritoriesNews item, BHP
DS1992-0537
1992
Gems & GemologyGems & GemologyClaim staking rush in CanadaGems and Gemology, Vol. 28, No. 2, Summer pp. 129Northwest TerritoriesNews item, Diamond prospecting
DS1992-0538
1992
Gems & GemologyGems & GemologyVisit to a small diamond mining operation in South AfricaGems and Gemology, Vol. 28, No. 2, Summer pp. 130South AfricaNews item, Longland area
DS1992-0539
1992
Gems & GemologyGems & GemologyNew treatment plant at Alexander BayGems and Gemology Gem News section, Vol. 28, Fall, p. 198South AfricaNews item, Rietfontein South plant
DS1992-0540
1992
Gems & GemologyGems & GemologyVenetia mine officially opensGems and Gemology Gem News section, Vol. 28, Fall, p. 199South AfricaNews item, Venetia mine
DS1992-0541
1992
Gems & GemologyGems & GemologyDe Beers signs prospecting agreement with TanzaniaGems and Gemology, Vol. 28, No. 2, Summer pp. 130TanzaniaNews item, De Beers
DS1992-0542
1992
Gems & GemologyGems & GemologyProspecting reveals kimberlite pipes in UkraineGems and Gemology, Vol. 28, No. 2, Summer pp. 129UKraine, RussiaNews item, Diamond prospecting -Azov
DS1992-0543
1992
Gems & GemologyGems & GemologyDat a suggest strong, changing U.S. diamond marketGems and Gemology, Vol. 27, No. 4, pp. 254United StatesNews item, Diamond markets
DS1992-0544
1992
Gems & GemologyGems & GemologyG.E. synthesizers large carbon-13 diamondsGems and Gemology, Vol. 27, No. 4, pp. 254United StatesNews item, G.E. synthetic diamonds
DS1992-0545
1992
Gems & GemologyGems & GemologyDe Beers and the Republic of Sakha sign sales agreementGems and Gemology, Vol. 28, No. 2, Summer pp. 129Russia, SakhaNews item, De Beers
DS1992-0546
1992
Gems & GemologyGems & GemologySmall industrials in UzbekistanGems and Gemology, Vol. 28, No. 2, Summer pp. 129Russia, UzbekistanNews item, Tashkent area
DS1992-0547
1992
Gems & GemologyGems & GemologyCheap cut diamonds from Yakutia... brief overview of Russian articleGems and Gemology, 28, No. 4, Winter p. 280Russia, YakutiaNews item, Diamond cutting
DS1993-0501
1993
Gems & GemologyGems & GemologyThe rarest gem.. brief review of article from Europa StarGems and Gemology Gemological Abstracts, Vol. 29, Summer p. 144GlobalDiamond -coloured, History
DS1993-0502
1993
Gems & GemologyGems & GemologyFlanders brilliant cutGems and Gemology Gem News, Vol. 29, Summer p. 130GlobalDiamond cutting, Flanders
DS1993-0503
1993
Gems & GemologyGems & GemologyStar cut diamondsGems and Gemology, Vol. XXIX, Spring pp. p. 52GlobalDiamond gem news
DS1993-0504
1993
Gems & GemologyGems & GemologyBlue diamond with unusual inclusionsGems and Gemology, Vol. XXIX, Spring pp. p. 47GlobalDiamond gem trade notes
DS1993-0505
1993
Gems & GemologyGems & GemologyLaser-assisted filling in diamondGems and Gemology, Vol. XXIX, Spring pp. p. 48GlobalDiamond gem trade notes
DS1993-0506
1993
Gems & GemologyGems & GemologyExtensive subtle fracture filling in a diamondGems and Gemology Gem Trade Lab notes, Vol. 29, Summer p. 123GlobalDiamond inclusions, Laboratory studies
DS1993-0507
1993
Gems & GemologyGems & GemologyIrridescent dislocation in a diamond.Gems and Gemology Gem Trade Lab notes, Vol. 29, Summer p. 123GlobalDiamond inclusions, Laboratory studies
DS1993-0508
1993
Gems & GemologyGems & GemologyClarity enhanced diamonds being marketed in Australia. Brief review of article in Isreal DiamondsGems and Gemology Gemological Abstracts, Vol. 29, Summer p. 144GlobalDiamond jewellery marketing
DS1993-0509
1993
Gems & GemologyGems & GemologyTreated green diamond.Gems and Gemology Gem Trade Lab notes, Vol. 29, Summer p. 124GlobalDiamond -surface radioactive treatment, Laboratory studies
DS1993-0510
1993
Gems & GemologyGems & GemologyDe Beers now marketing high quality, high-pressue synthetic diamondproducts... brief review of artilce from Industrial Diamond Review by Dr. C.PhaalGems and Gemology Gem News, Vol. 29, Summer p. 130GlobalDiamond synsthesis, De Beers
DS1993-0511
1993
Gems & GemologyGems & GemologyMounted diamonds mistaken for sumulants.Gems and Gemology Gem Trade Lab notes, Vol. 29, Summer p. 124GlobalDiamond, Laboratory studies
DS1993-0512
1993
Gems & GemologyGems & GemologyBrief overview of the 24th. International Gemmological Conference held Paris October 1993. Levinson, Kanis, Bosshart, Tillander short precis of theirtalks.Gems and Gemology, Vol. 29, Winter pp. 290-292.GlobalNews item, Diamond colour -green to blue
DS1993-0513
1993
Gems & GemologyGems & GemologyDiamonds for connoisseurs... abstract of article from JewelleryInternational, No. 11, 1992, pp. 31-34, 37Gems and Gemology, Vol. XXIX, Spring pp. p. 72GlobalNews item, Fancy coloured diamonds
DS1993-0514
1993
Gems & GemologyGems & GemologyRussia to de Beers: we want more control. Abstract of article in Jewellers Circular Keystone, Vol. 164, no. 1, January 1993 pp. 50-60Gems and Gemology, Vol. XXIX, Spring pp. p. 72-3Russia, Commonwealth of Independent States (CIS)News item, De Beers
DS1994-0588
1994
Gems & GemologyGems & GemologyFancy coloured roughGems and Gemology, Vol. Spring p. 40.GlobalDiamond morphology
DS1994-0589
1994
Gems & GemologyGems & GemologyDiamond with unusual color zoningGems and Gemology, Vol. 30, Summer pp. 116.GlobalDiamond morphology, Color
DS1994-0590
1994
Gems & GemologyGems & GemologyCharacteristic inclusions in fancy coloured diamondsGems and Gemology, Vol. Spring p. 41.GlobalDiamond morphology, Diamond inclusions
DS1994-0591
1994
Gems & GemologyGems & GemologyLaser drill holes of natural inclusions?Gems and Gemology, Vol. 30, Summer pp. 115, 116.GlobalDiamond morphology, Laser drill holes
DS1994-0592
1994
Gems & GemologyGems & GemologyDiamond -light yellow treated colorGems and Gemology, Vol. 30, winter p. 264.GlobalDiamonds -colour, Diamond value
DS1994-0593
1994
Gems & GemologyGems & GemologyColor origin " unnamed Brown"Gems and Gemology, Vol. Spring p. 39, 40.GlobalDiamonds notable, Brown diamond
DS1994-0594
1994
Gems & GemologyGems & GemologyCentenary diamond gradedGems and Gemology, Vol. Spring p. 39.GlobalDiamonds notable, Centenary
DS1994-0595
1994
Gems & GemologyGems & GemologyNear colorless Russian synthetic diamond examinedGems and Gemology, Vol. 30, Summer pp. 123, 124.RussiaDiamond color, Synthetic diamonds
DS1994-0596
1994
Gems & GemologyGems & GemologyUpdate on diamond production in the former USSR...1/4 page extracted From diamond Intelligence Briefs.Gems and Gemology, Vol. 30, Fall p. 192.RussiaNews item, Diamond production
DS1995-0596
1995
Gems & GemologyGems & GemologyArgyle output flat.. extract from Diamond Industry WeekGems and Gemology, Abstracts, Vol. 31, Fall p. 220.AustraliaNews item, Deposit -Argyle
DS1995-0597
1995
Gems & GemologyGems & GemologyBotswana backs renewals with the CSO. extract from Mazal U'BrachaGems and Gemology, Vol. 31, Winter pp. 291.BotswanaNews item, CSO
DS1995-0598
1995
Gems & GemologyGems & GemologyInclusions affect body colour...in diamondGems and Gemology, Lab Notes, Vol. 31, Fall p. 197.GlobalDiamond inclusions
DS1995-0599
1995
Gems & GemologyGems & GemologyDiamond with mobile diamond inclusionGems and Gemology, Gem News, Vol. 31, Fall p. 204.GlobalDiamond inclusions
DS1995-0600
1995
Gems & GemologyGems & GemologyDiamond with strain phantomGems and Gemology -Gem trade notes section, Vol. 31, summer p. 120.GlobalDiamond morphology
DS1995-0601
1995
Gems & GemologyGems & GemologyTreated color pink diamondGems and Gemology -Gem trade notes section, Vol. 31, summer p. 121.GlobalDiamond morphology
DS1995-0602
1995
Gems & GemologyGems & GemologyUnusual gem crystal.. aggregate of two rounded crystalsGems and Gemology -Gem trade notes section, Vol. 31, summer p. 122.GlobalDiamond morphology
DS1995-0603
1995
Gems & GemologyGems & GemologyMore firms processing fracture-filled diamondsGems and Gemology -Gem News, Vol. 31, summer p. 129.GlobalDiamond morphology
DS1995-0604
1995
Gems & GemologyGems & GemologyDiamond -fancy black, with ironGems and Gemology -Lab notes, Vol. 31, Winter pp. 266.GlobalDiamond morphology, Diamond -black
DS1995-0605
1995
Gems & GemologyGems & GemologySynthetic diamond suite..Gems and Gemology -Gem trade notes section, Vol. 31, summer p. 122-123.GlobalDiamond morphology, Diamond -synthesis
DS1995-0606
1995
Gems & GemologyGems & GemologyDiamonds grown from liquid at 1 atm. extract from Diamond Industry WeekGems and Gemology, Vol. 31, Winter pp. 296.GlobalDiamond synthetic
DS1995-0607
1995
Gems & GemologyGems & GemologyNew diamond cuts... Context and Spirit SunGems and gemology, GemNews, Vol. 31, Spring, p. 59-60.GlobalMineralogy, Diamond cutting
DS1995-0608
1995
Gems & GemologyGems & GemologyTriangular inclusions in diamondGems and gemology, Gem Trade Notes, Vol. 31, Spring, p. 53.GlobalMineralogy, Diamond inclusions
DS1995-0609
1995
Gems & GemologyGems & GemologyTreated color red - synthetic diamondsGems and gemology, Gem Trade Notes, Vol. 31, Spring, p. 53-4.GlobalMineralogy, Diamond synthesis
DS1995-0610
1995
Gems & GemologyGems & GemologySome historical trends in diamond industry - brief abstract of paper at25th. International Gemmological ConferenceGems and Gemology -Gem news, Vol. 31, Winter pp. 274-5.GlobalNews item, Diamond industry trends
DS1995-0611
1995
Gems & GemologyGems & GemologyWorld diamond production holds at 1993 levels. Extract from, New YorkDiamonds.Gems and Gemology, Vol. 31, Winter pp. 292.GlobalNews item, Diamond production 1994
DS1995-0612
1995
Gems & GemologyGems & GemologyFluid inclusions in diamonds - brief abstract of paper presented at 25th.International Gemmological Conference.Gems and Gemology -Gem news, Vol. 31, Winter pp. 274.GlobalNews item, Diamonds -inclusions
DS1995-0613
1995
Gems & GemologyGems & GemologySynthetic diamonds misrepresented as Canadian rough...from SaskatchewanGems and Gemology -Gem News, Vol. 31, summer p. 129.SaskatchewanDiamond synthesis, Diamond fraud
DS1996-0493
1996
Gems & GemologyGems & GemologyMatrix diamond specimens from Chin a and Russia shown at Tucson Gem showGems and Gemology, Gem News, Vol. 32, Spring p. 52.China, RussiaNews item, Diamond in matrix specimens
DS1996-0494
1996
Gems & GemologyGems & GemologyDiamonds from Kelsey Lake, ColoradoGems and gemology, Gem News, Vol. 32, Winter, pp. 282-3.ColoradoDiamond morphology, crystallography, Redaurum Limited
DS1996-0495
1996
Gems & GemologyGems & GemologyBook review of " the dealers book of gems and diamonds". Sevdermish andMashiah. $ 98.00Gems and Gemology, Vol. 32, fall pp. 223.GlobalBook review, Dealers book of gems and diamonds
DS1996-0496
1996
Gems & GemologyGems & GemologyDiamond - fracture filledGems and gemology, Lab notes, Vol. 32, Winter, pp. 278-9.GlobalDiamond crystallography
DS1996-0497
1996
Gems & GemologyGems & GemologyFingerprints of natural diamonds - observations with cathodluminescenceGems and Gemology, Gem News, Vol. 32, Spring p. 60.GlobalDiamond, Catholuminesence
DS1996-0498
1996
Gems & GemologyGems & GemologyChatham synthetic "white" diamonds at JCK showGems and Gemology, Vol. 32, fall pp. 214.GlobalDiamonds - synthetic
DS1996-0499
1996
Gems & GemologyGems & GemologySynthetic moissanite as a diamond simulantGems and Gemology, Gem News, Vol. 32, Spring p. 52.GlobalNews item, Moissanite
DS1996-0500
1996
Gems & GemologyGems & GemologySynthetic diamonds in the marketplace.. Morion CompanyGems and Gemology, Gem News, Vol. 32, Spring p. 52.GlobalNews item, Morion Company
DS1996-0501
1996
Gems & GemologyGems & GemologyA notable yellow synthetic diamond from RussiaGems and Gemology, Lab Notes, Vol. 32, Spring p. 44.RussiaNews item, Diamond synthesis
DS1997-0376
1997
Gems & GemologyGems & GemologyHow many diamonds are there in Arkansaw? asks Prof. A.A. LevinsonGems and Gemology, Fall, p. 220-221.ArkansasNews item, Deposit - Crater of Diamonds
DS1997-0377
1997
Gems & GemologyGems & GemologyOpalescent and other unusual diamonds... at the Tucson mineral showGems and Gemology, Vol. 33, Spring, p. 60-61.ColoradoDiamond crystallography, Kelsey Lake diamonds
DS1997-0378
1997
Gems & GemologyGems & GemologyTwo noteworthy stones from the Americas... Kelsey Lake diamond..Gems and Gemology, Vol. 33, Spring, p. 54.ColoradoNews item, Kelsey Lake yellow diamond
DS1997-0379
1997
Gems & GemologyGems & GemologyCathodluminescence of yellow diamondsGems and Gemology, Vol. 33, winter, pp. 298.GlobalDiamond - colour, Cathodluminescence
DS1997-0380
1997
Gems & GemologyGems & GemologyThe 26th. International Gemmological Conference held Oct. 3 ... brief reviews of papersGems and Gemology, Vol. 33, winter, pp. 298-300.GlobalDiamond conference
DS1997-0381
1997
Gems & GemologyGems & GemologyIdentifying filled fractures: new challengesGems and Gemology, Vol. 33, Spring, p. 56.GlobalDiamond crystallography
DS1997-0382
1997
Gems & GemologyGems & GemologyDiamond inclusions in corundumGems and Gemology, Vol. 33, winter, pp. 299.GlobalDiamond inclusions
DS1997-0383
1997
Gems & GemologyGems & GemologyMineral inclusions in large Yakutian diamond crystalsGems and Gemology, Vol. 33, winter, pp. 300.GlobalDiamond inclusions
DS1997-0384
1997
Gems & GemologyGems & GemologyThe diamond pipeline into the third milleniumGems and Gemology, Vol. 33, winter, pp. 299.GlobalDiamond market
DS1997-0385
1997
Gems & GemologyGems & GemologyThe morphology of natural gem diamondsGems and Gemology, Vol. 33, winter, pp. 300.GlobalDiamond morphology
DS1998-0487
1998
Gems & GemologyGems & GemologyGem crystals from Russia and China.. again at Tucson showGems and Gemology, Vol. 34, Spring, p. 50.Russia, ChinaNews item, Diamond morphology - crystals
DS1999-0239
1999
Gems & GemologyGems & GemologyDiamond presentations at the Prospectors and Developers Association of Canada (PDAC) conference. Brief overview by BramJanse.Gems and Gemology Gem News, Vol. 35, summer, p. 142-3.GlobalDiamond - talks at Prospectors and Developers Association of Canada (PDAC).
DS1999-0240
1999
Gems & GemologyGems & GemologyHeat exposure may affect reflectance testing of synthetic moissaniteGems and Gemology Gem News, Vol. 35, summer, p. 80-81.GlobalMoissanite
DS1999-0241
1999
Gems & GemologyGems & GemologyFashioned diamonds from the Ekati mine, Northwest Territories, Canada....brief note.Gems and Gemology Gem News, Spring, p. 47.Northwest TerritoriesNews item, Ekati diamonds, Polar Bear logo
DS1999-0242
1999
Gems & GemologyGems & GemologySynthetic diamonds widely available... Russian Coloured Stone CoGems and Gemology Gem News, Spring, p. 47, 48.RussiaNews item, Synthetic diamonds
DS2000-0327
2000
Gems & GemologyGems & GemologyNew diamond cut - Tycoon cut(rectangular or square with mixed cut with step cut facets.Gems and Gemology Gem News, Vol. 36, No. 2, Summer, p. 160.GlobalDiamond - cutting
DS2002-0548
2002
Gems & GemologyGems & GemologyDiamond stories: enduring change on 47th. Street.R.R. Shield 234p. publ. Cornell University Press. $ 30.00Gems & Gemology, Vol. 38, Summer, p. 189.GlobalBook - review
DS2002-0549
2002
Gems & GemologyGems & GemologyDiamonds; in the heart of the Earth, in the Heart of the Stars, at the Heart of Power. H. Bari, V. Sautter. Vilo Int. Editions, Adam Biro Paris, 351p. $60.00Gems & Gemology, Vol. 38, Summer, p. 190.GlobalBook - review
DS2002-0550
2002
Gems & GemologyGems & GemologyAGU meeting examines diamond provenance. Brief overview of speakers Haggerty, Taylor, Deines, Cartigny, Hauri, Sobolev, Harris, Farquhar, AnckarGems & Gemology, Vol. 38, Summer, pp. 170-171.GlobalConference - brief overview, Conflict diamond - source/provenance
DS2002-0551
2002
Gems & GemologyGems & GemologyComments on the GIA analysis of diamond "fire". GIA's study of proportions on the appearance of a round brilliant diamond.......Gems & Gemology, Vol. 38, Summer, pp. 124-126.GlobalDiamond - cutting, cone of brilliance
DS2003-0451
2003
Gems & GemologyGems & GemologyThe eras of the diamond. Outline of rich lore of diamonds with non technical approachGems & Gemology, Vol. 39,3, Fall, p. 252. [email protected]GlobalBook - ad
DS2003-0452
2003
Gems & GemologyGems & GemologySome unusual type II diamondsGems & Gemology, Vol. 39,3, Fall, p. 214-5.GlobalLuminescent features
DS2003-0453
2003
Gems & GemologyGems & GemologyDigital geologic map of Madagascar. Brief overview and background)Gems & Gemology, Vol. 39, Summer, p.164. Contact www.gospatial.comMadagascarNews item, Map - GIS
DS2003-0454
2003
Gems & GemologyGems & GemologyUpdate on diamond mining and exploration in the Slave Province, NWT and northernGems & Gemology, Vol. 39,3, Fall, pp. 222-5.Northwest Territories, AlbertaField trip
DS200412-0642
2003
Gems & GemologyGems & GemologySome unusual type II diamonds.Gems & Gemology, Vol. 39,3, Fall, p. 214-5.TechnologyLuminescent features
DS200412-0643
2003
Gems & GemologyGems & GemologyUpdate on diamond mining and exploration in the Slave Province, NWT and northern Alberta. Brief overview of field trip held 8th.Gems & Gemology, Vol. 39,3, Fall, pp. 222-5.Canada, Northwest Territories, AlbertaField trip
DS200412-0644
2003
Gems & GemologyGems & GemologyThe eras of the diamond. Outline of rich lore of diamonds with non technical approach.Gems & Gemology, Vol. 39,3, Fall, p. 252. julessaurer @amsterdamsauer.cGlobalBook - ad
DS200412-0645
2003
Gems & GemologyGems & GemologyDigital geologic map of Madagascar. Brief overview and background).Gems & Gemology, Vol. 39, Summer, p.164. Contact gospatial.comAfrica, MadagascarNews item Map - GIS
DS200412-0646
2004
Gems & GemologyGems & GemologyWHALES AND RAVENS to recover diamonds. Brief abstract of one page article in South African Mining August 2003 p. 21.Gems & Gemology, Vol. 40, 2, Summer p. 189. abstract only.TechnologyDe Beers - diamond recovery process
DS200512-0331
2005
Gems & GemologyGems & GemologyHPHT treated IIa yellow diamond.Gems & Gemology, Vol. 41, 1, Spring p. 43-46.Diamond - colour
DS200512-0332
2005
Gems & GemologyGems & GemologyDiamond - with body color possible affected by the 3H defect ( radiation).Gems & Gemology, Vol. 41, 1, Spring p. 42-3.Diamond - colour
DS200512-0333
2005
Gems & GemologyGems & GemologyIn review - synthetic diamonds.. the best of Gems & Gemology on the subject of synthetic diamonds now available in one comprehensive research volume.Gems & Gemology, Vol. 41, 1, Spring p. 41 $ 49.95 gia.eduDiamond - synthesis
DS200512-0334
2005
Gems & GemologyGems & GemologyWorld diamond conference, Perth Australia. Overview by Bram Janse.Gems & Gemology, Vol. 41, 1, Spring p. 70.AustraliaNews item - World Diamond Conference
DS200612-0433
2006
Gems & GemologyGems & GemologyColored Diamonds. IN REVIEW. The best of Gems & Gemology on the subject of coloured diamonds from their issues.Gems & Gemology, 2 book set $ 59.95 gia.eduGlobalBook - coloured diamonds
DS200612-0434
2006
Gems & GemologyGems & GemologyTwo diamonds from the same octahedron.Gems & Gemology Lab Notes, Vol. 42, 1, Spring, p. 56-57.TechnologyNews item - cutting
DS200612-0435
2006
Gems & GemologyGems & GemologyPink diamond with etch channels at the intersections of glide planes.Gems & Gemology Lab Notes, Vol. 42, 1, Spring, p. 56.TechnologyNews item - pink diamond colour
DS200612-0436
2006
Gems & GemologyGems & GemologyUnusual translucent brown-orange diamond.Gems & Gemology Lab Notes, Vol. 42, 1, Spring, p. 57-58.TechnologySpectroscopy
DS201012-0226
2010
Gems & GemologyGems & GemologyFancy vivid blue HPHT treated type IIb diamond.Gems & Gemology Lab Notes, Vol. 46, 2, p. 141-142.TechnologyDiamond colour
DS201012-0227
2010
Gems & GemologyGems & GemologyFancy vivid blue HPHT treated type IIb diamond.Gems & Gemology Lab Notes, Vol. 46, 2, p. 141-142.TechnologyDiamond colour
DS201012-0228
2010
Gems & GemologyGems & GemologyBlack diamond with solid CO2, Micro inclusions and phosphorescent zones.Gems & Gemology Lab Notes, Vol. 46, 2, p. 140-141.TechnologyDiamond inclusions
DS201012-0229
2010
Gems & GemologyGems & GemologyBlack diamond with solid CO2, Micro inclusions and phosphorescent zones.Gems & Gemology Lab Notes, Vol. 46, 2, p. 140-141.TechnologyDiamond inclusions
DS201012-0230
2010
Gems & GemologyGems & GemologyInteresting display of the H3 defect in a colourless type IIa diamond.Gems & Gemology Lab Notes, Vol. 46, 2, p. 142-143.TechnologyDiamond morphology
DS201012-0231
2010
Gems & GemologyGems & GemologyCVD synthetic diamond over one carat.Gems & Gemology Lab Notes, Vol. 46, 2, p. 143-144.TechnologyDiamond synthetics
DS201112-0349
2011
Gems & GemologyGems & GemologyBlack diamond coloration enhanced by a coating.Gems & Gemology Brief, Vol. 20, 10, 1/2p.TechnologyBlack diamond
DS201112-0350
2011
Gems & GemologyGems & GemologyLarge Cape diamond HPHT treated...28.65 diamond.. one of the largest ever graded by GIA.G & G Brief, Vol. 2, no. 5, p. 2.Africa, South AfricaDiamond morphology - HPHT
DS201112-0351
2011
Gems & GemologyGems & GemologyGemesis releases CVD grown synthetic diamonds. (market)G & G Brief, May 3, 1/2p.United StatesNews item - Gemesis
DS201112-0352
2011
Gems & GemologyGems & GemologyHPHT treatment used even for subtle diamond color enhancement... type 11aG & G Brief, May 3, 1/2p.TechnologyNews item - HPHT
DS201112-0353
2011
Gems & GemologyGems & GemologyNatural color pink, Coated diamondsG & G Brief, Vol. 2, 8, June 7, 1/2p.TechnologyNews item - pink diamond
DS201112-0354
2010
Gems & GemologyGems & GemologyLab sees more 5 to 10 + HPHT treated diamonds.G & G Brief, Dec. 7, 1/8p.TechnologyNews item - treated diamonds
DS201112-0355
2011
Gems & GemologyGems & GemologySilicon feature in HPHT synthetic diamond indicates treatment.G & G Brief, Jan. 10, 1/2p.TechnologyNews item - Type IIb synthetics
DS201112-0356
2011
Gems & GemologyGems & GemologyFluorescence contributes to strong pink colour in treated synthetic diamonds.Gems & Gemology Brief, Vol. 20, 10, 1/2p.TechnologySynthetic diamonds
DS201112-0357
2011
Gems & GemologyGems & GemologyGlowing type 1aB diamonds.G & G Brief, April 5, 1/2p.TechnologyThermoluminesence
DS201212-0230
2012
Gems & GemologyGems & GemologyDiamond mining to resume in Ghana.Gems & Gemology Lab Notes, Vol. 3, 5, Feb. 14, 1/2p.Africa, GhanaDeposit - Birim River
DS201212-0231
2012
Gems & GemologyGems & GemologyType IIb diamondGems & Gemology Lab Notes, Vol. 3, 5, Feb. 14, 1/2p.TechnologyType Iib
DS201712-2700
2017
Gems & GemologyGems & GemologyHigh quality diamond from Brazilian kimberlite. Lab notes - LipariGems & Gemology, Vol. 53, 3, p. 360.South America, Brazil, Bahiadeposit - Brauna
DS201804-0691
2017
Gems & GemologyGems & GemologySynthetic moissanite.Gems & Gemology Lab Notes, Vol. 53, 4, p. 462.Technologymoissanite
DS201809-2025
2018
Gems & GemologyGems & GemologyChart: Features of synthetic diamond chart in colour.Gems & Gemology, Vol. 54, 2, p. 150.Globalsynthetics
DS200512-0323
2004
Gems & Gemology Gem NewsGems & Gemology Gem NewsA natural diamond with very high Ni content.Gems & Gemology, Vol. 40, 4, Winter, p. 334-6.Diamond - nickel nitrogen inclusions
DS1991-0553
1991
Gems & Gemology Lab NotesGems & Gemology Lab NotesDiamond : electron treated; fracture filling; green surface colored roughGems and Gemology, Vol. 27, Summer pp. 108-110GlobalGem notes, Diamonds -treated
DS1992-0548
1992
Gems & Gemology Lab NotesGems & Gemology Lab NotesHeat-damaged filled diamondGems and Gemology, Vol. 28, No. 2, Summer pp. 123GlobalDiamond morphology, Heat treatment
DS1992-0549
1992
Gems & Gemology Lab NotesGems & Gemology Lab NotesLarge chameleon-type diamondGems and Gemology, Vol. 28, No. 2, Summer pp. 124GlobalDiamond morphology, Optical properties
DS1992-0550
1992
Gems & Gemology Lab NotesGems & Gemology Lab NotesTreated black diamondGems and Gemology, Vol. 28, No. 2, Summer pp. 124GlobalDiamond morphology, Radioactivity
DS1996-0502
1996
Gems & Gemology Lab NotesGems & Gemology Lab NotesImitation crystals.... cubic zirconiaGems and Gemology, Vol. 32, fall pp. 205.GlobalDiamond - zirconia
DS1996-0503
1996
Gems & Gemology Lab NotesGems & Gemology Lab NotesDifferent colors from the same roughGems and Gemology, Vol. 32, fall pp. 204-5.GlobalDiamond colours
DS1996-0504
1996
Gems & Gemology Lab NotesGems & Gemology Lab NotesRare color: fancy intense pinkish orangeGems and Gemology, Vol. 32, fall pp. 206.GlobalDiamond colours
DS1996-0505
1996
Gems & Gemology Lab NotesGems & Gemology Lab NotesA suite of treated color pink to purple diamondsGems and Gemology, Vol. 32, fall pp. 207-8.GlobalDiamond colours
DS1996-0506
1996
Gems & Gemology Lab NotesGems & Gemology Lab NotesNatural with unseen 'flaws'Gems and Gemology, Vol. 32, fall pp. 205-6.GlobalDiamond inclusions
DS1997-0386
1997
Gems & Gemology Lab NotesGems & Gemology Lab NotesMysteriously fractured diamondsGems and Gemology, Vol. 33, winter, pp. 295.GlobalDiamond - fracture
DS1997-0387
1997
Gems & Gemology Lab NotesGems & Gemology Lab NotesFracture filled pink diamondGems and Gemology, Vol. 33, winter, pp. 294-5.GlobalDiamond - fracture filling
DS1997-0388
1997
Gems & Gemology Lab NotesGems & Gemology Lab NotesDiamond acting as a heat sink....Gems and Gemology, Vol. 33, winter, pp. 293-4.GlobalDiamond property, Heat sink
DS1997-0389
1997
Gems & Gemology Lab NotesGems & Gemology Lab NotesRare fancy vivid orangeGems and Gemology, Fall, p. 213.South AfricaNews item, Diamond - orange
DS2000-0328
2000
Gems & Gemology Lab NotesGems & Gemology Lab NotesFancy white diamonds... rare ..Gems and Gemology Lab Notes, Vol. 36, No. 2, Summer, p. 156.GlobalDiamond - colour
DS2000-0329
2000
Gems & Gemology Lab NotesGems & Gemology Lab NotesBlue, zoned diamond examinedGems and Gemology Lab Notes, Vol. 36, No. 2, Summer, p. 156-7.GlobalDiamond - colour
DS200512-0324
2005
Gems & Gemology Lab notesGems & Gemology Lab notesDiamond - fracture filled, with varying results.Gems & Gemology, Vol. 41, 2, Summer p. 164-165.TechnologyDiamond morphology - heat treatment
DS200512-0325
2005
Gems & Gemology Lab notesGems & Gemology Lab notesLarge diamond with micro inclusions of carbonates and solid CO2.Gems & Gemology, Vol. 41, 2, Summer p. 165-6.TechnologyDiamond morphology - inclusions
DS200512-0326
2005
Gems & Gemology Lab notesGems & Gemology Lab notesDiamond with unusual laser drill holes.Gems & Gemology, Vol. 41, 2, Summer p. 170 (1/4p.)TechnologyDiamond morphology - laser
DS200512-0327
2005
Gems & Gemology Lab notesGems & Gemology Lab notesNatura; Type Ib diamond with unusually high nitrogen content.Gems & Gemology, Vol. 41, 2, Summer p. 168-9.TechnologyDiamond morphology - nitrogen
DS200512-0328
2005
Gems & Gemology Lab notesGems & Gemology Lab notesLight blue diamond, with type IIb and IIa zones.Gems & Gemology, Vol. 41, 2, Summer p. 167-8.TechnologyDiamond morphology - zoning
DS200512-0329
2004
Gems & Gemology Lab notesGems & Gemology Lab notesLuminescent 'Hopper' diamonds.Gems & Gemology, Vol. 40, 4, Winter, p. 324.Africa, Democratic Republic of CongoNews item - faces grown more at edge than centre
DS200512-0330
2004
Gems & Gemology Lab notesGems & Gemology Lab notesMagnetic natural pink diamonds.Gems & Gemology, Vol. 40, 4, Winter, p. 324.News item - pink diamonds
DS201012-0221
2010
Gems & Gemology Lab notesGems & Gemology Lab notesIdentification of irradiated black diamonds.Gems & Gemology, Vol. 46, 1, Spring p. 50.TechnologyColour morphology
DS201012-0222
2010
Gems & Gemology Lab notesGems & Gemology Lab notesLarge HPHT treated type 11b blue diamond.Gems & Gemology, Vol. 46, 1, Spring pp. 50-51.TechnologyColour morphology
DS201012-0223
2010
Gems & Gemology Lab notesGems & Gemology Lab notesPink diamonds colored by multiple treatment processes.Gems & Gemology, Vol. 46, 1, Spring pp. 51..TechnologyColour morphology
DS201012-0224
2010
Gems & Gemology Lab notesGems & Gemology Lab notesType 11a greenish yellow diamond coloured by IR-inactive nitrogen.Gems & Gemology, Vol. 46, 1, Spring pp. 52.TechnologyColour morphology
DS201012-0225
2010
Gems & Gemology Lab notesGems & Gemology Lab notesRed CVD synthetic diamond with multiple treatments.Gems & Gemology, Vol. 46, 1, Spring pp. 52-53.TechnologySynthetic diamonds
DS202109-1467
2021
Gems & JeweleryGems & JeweleryPerseverance on the banks of the Itoco River.Gems & Jewelery, Vol. 30, 2, p. 8.South America, Colombiaemerald
DS202109-1468
2021
Gems & JeweleryGems & JeweleryWhat will happen to fancy pink diamonds? Argyle closure.Gems & Jewelery, Vol. 30, 2, pp. 14-15.Australia, globaldeposit - Argyle
DS201808-1746
2018
Gems & JewelleryGems & JewelleryFocus: Looking for the light. Fluorescence in gemstones.Gems & Jewellery, Vol. 27, 2, pp. 12-14.Technologyfluorescence
DS201808-1747
2018
Gems & JewelleryGems & JewelleryOnly a matter of time: Argyle, a sparkling history.Gems & Jewellery, Vol. 27, 2, 20-21.Australiadeposit - Argyle
DS201811-2571
2018
Gems & JewelleryGems & JewelleryWaiting for the lift…. Photograph only of miners down to Bultfontein, Dutoitspan mines.Gems & Jewellery, Autumn p. 8-9.Africa, South Africamining
DS201904-0739
2019
Gems & JewelleryGems & JewelleryMazarin's passion for diamonds left to Louis IVX by Cardinal Mazarin. ( Sancy)Gems&Jewellery, Vol. 28, 1. pp. 32-38.Europe, Francehistory
DS202205-0683
2022
Gems & JewelleryGems & JewelleryThe rebirth of Yogo sapphire production at historic mine.Gems&Jewellery, Vol. 31, 1, pp. 19-21.United States, Montanadeposit - Yogo
DS202205-0684
2022
Gems & JewelleryGems & JewelleryLarge diamonds: why now?Gems&Jewellery, Vol. 31, pp. 30-31.Africa, Botswanadeposit - Karowe
DS202205-0685
2022
Gems & JewelleryGems & JewelleryThe cut or the stone? ( Large carbonado auction)Gems&Jewellery, Vol. 31, pp. 40-41.Globalcarbonado
DS200612-0437
2005
Gems &.GemologyGems &.Gemology, Lab NotesStrongly coloured natural type IIb blue diamonds.Gems & Gemology, Vol. 41, 3, Fall, p.258-9..TechnologyDiamond - colour
DS200612-0438
2005
Gems &.GemologyGems &.Gemology, Lab NotesDiamond dyed rough.Gems & Gemology, Vol. 41, 3, Fall, p.257-258.TechnologyDiamond - colour
DS1996-0507
1996
Gems and GemologyGems and Gemology, Gemological Abstracts1995 record year for diamond imports, exports. abstract of NationalJeweler, April 1, 1996 p. 76.Gems and Gemology, Summer, p. 144.GlobalDiamond exports
DS1996-0508
1996
Gems and GemologyGems and Gemology, Gemological AbstractsDiscard small diamonds - they're not worth the effort. Abstract Diamond Industry Week, Vol. 2, 39 Oct 9, '95 p4Gems and Gemology, Summer, p. 144.GlobalDiamond prices
DS200512-0335
2004
Gems and Gemology Lab NotesGems and Gemology Lab NotesFour blue diamonds from a historic necklace. Culli nan necklace.Gems & Gemology, Vol. 40, 3, Fall, pp. 241-245.Diamonds notable - Cullinan necklace
DS201911-2550
2018
Genc, B.Mutandwa, B., Genc, B.Leveraging Zimbabwe's mineral endowment for economic transformation and human development.Resources Policy, Vol. 58, pp. 230-239.Africa, ZimbabweREE

Abstract: For the past two decades, Zimbabwe has experienced a pervasive economic collapse. Most of the challenges were caused by policy inconsistencies, bad policy choices, economic mismanagement and political instability. This led to deindustrialization with a sharp decline in manufacturing and agriculture productivity and output, which consequently caused a sharp increase in unemployment and poverty. Although it is not fully developed, the mining industry in Zimbabwe presents an opportunity for economic stimulation that may lead to economic recovery, but requires broad-based economic reforms. This paper presents the findings of a review, and benchmarking of Zimbabwe's policies, which affect mining investment, inclusive economic growth and human development. The policies were benchmarked and compared to similar policies of Botswana, Namibia and South Africa using the Natural Resources Benchmarking Charter Framework. The outcomes of the review and benchmarking process were taken into consideration when coming up with policy suggestions that are meant to economically transform Zimbabwe, which at the same time brings sustained human development. The work reported in this paper is part of an MSc research study in the School of Mining Engineering at the University of the Witwatersrand.
DS1992-0553
1992
Gendzwill, D.Gent, M.R., Kreis, L.K., Gendzwill, D.The Maple Creek structure, southwestern SaskatchewanSaskatchewan Report Summary of Investigations 1992, miscellaneous Report No. 92-4, pp. 204-208SaskatchewanGeophysics -seismics, magnetics, gravity, Structure
DS1987-0712
1987
Gendzwill, D.J.Stauffer, M.R., Gendzwill, D.J.Fractures in the northern plains, stream patterns and the midcontinent stress field.Canadian Journal of Earth Sciences, Vol. 24, pp. 1086-97.Saskatchewan, MontanaGeophysics - seismics
DS1996-0509
1996
Gendzwill, D.J.Gendzwill, D.J., Matieshin, S.D.Seismic reflection survey of a kimberlite intrusion in the Fort a la Cornedistrict, Saskatchewan.Geological Survey of Canada, LeCheminant ed, OF 3228, pp. 251-253.SaskatchewanGeophysics -seismics, Fort a la Corne area
DS1990-0551
1990
Generalov, M.E.Generalov, M.E., Novogordova, M.I.Heteroelements in carbon matter from mineralized rocksInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 35RussiaGeochemistry, Carbon
DS200812-1283
2008
Geng, H.Xu, X., Griffin, W.L., O'Reilly, S.Y., Pearson, N.J., Geng, H., Zheng, J.Re-Os isotopes of sulfides in mantle xenoliths from eastern China: progressive modifications of lithospheric mantle.Lithos, Vol. 102, 3-4, pp.43-64.ChinaGeochronology
DS201911-2555
2019
Geng, J.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.
DS201809-2113
2018
Geng, M.Welford, K., Pearce, A., Geng, M., Dehler, S.A., Dickie, K.Crustal structure of Baffin Bay from constrained 3-D gravity inversion and deformable plate tectonic models. Geophysical Journal International, Vol. 214, 2, pp. 1281-1300. doi:1093/gji/ggy193Canada, NunavutGeophysics - gravity

Abstract: Mesozoic to Cenozoic continental rifting, breakup and spreading between North America and Greenland led to the opening, from south to north, of the Labrador Sea and eventually Baffin Bay between Baffin Island, northeast Canada and northwest Greenland. Baffin Bay lies at the northern limit of this extinct rift, transform and spreading system and remains largely underexplored. With the sparsity of existing crustal-scale geophysical investigations of Baffin Bay, regional potential field methods and quantitative deformation assessments based on plate reconstructions provide two means of examining Baffin Bay at the regional scale and drawing conclusions about its crustal structure, its rifting history and the role of pre-existing structures in its evolution. Despite the identification of extinct spreading axes and fracture zones based on gravity data, insights into the nature and structure of the underlying crust have only been gleaned from limited deep seismic experiments, mostly concentrated in the north and east where the continental shelf is shallower and wider. Baffin Bay is partially underlain by oceanic crust with zones of variable width of extended continental crust along its margins. 3-D gravity inversions, constrained by bathymetric and depth to basement constraints, have generated a range of 3-D crustal density models that collectively reveal an asymmetric distribution of extended continental crust, approximately 25-30?km thick, along the margins of Baffin Bay, with a wider zone on the Greenland margin. A zone of 5-13?km thick crust lies at the centre of Baffin Bay, with the thinnest crust (5?km thick) clearly aligning with Eocene spreading centres. The resolved crustal thicknesses are generally in agreement with available seismic constraints, with discrepancies mostly corresponding to zones of higher density lower crust along the Greenland margin and Nares Strait. Deformation modelling from independent plate reconstructions using GPlates of the rifted margins of Baffin Bay was performed to gauge the influence of original crustal thickness and the width of the deformation zone on the crustal thicknesses obtained from the gravity inversions. These results show the best match with the results from the gravity inversions for an original unstretched crustal thickness of 34-36?km, consistent with present-day crustal thicknesses derived from teleseismic studies beyond the likely continentward limits of rifting around the margins of Baffin Bay. The width of the deformation zone has only a minimal influence on the modelled crustal thicknesses if the zone is of sufficient width that edge effects do not interfere with the main modelled domain.
DS202010-1838
2020
Geng, X.Deng, L., Geng, X., Liu, Y., Zong, K., Zhu, L., Zhengwei, L., Hu, Z., Guodong, Z., Guangfu, C.Lithospheric modification by carbonatitic to alkaline melts and deep carbon cycle: insights from peridotite xenoliths of eastern China.Lithos, in press available 38p. PdfChinacarbonatite

Abstract: Carbonates in subducting oceanic slabs can survive beyond slab dehydration and be transferred into the deep mantle. Such deep carbon cycling plays a critical role in generating carbonatitic to alkaline melts. However, whether and how this process has influenced the lithospheric mantle still remains enigmatic. To address these issues, here we provide a detailed petrographic, in-situ chemical and Sr isotopic study on two mantle xenoliths (a wehrlite and a melt pocket-bearing peridotite) entrained by the Changle Miocene basalts from the eastern China. The Changle wehrlite contains carbonate melt inclusions and apatites and is merely enriched in clinopyroxene relative to the lherzolites. The clinopyroxenes are characterized by high (La/Yb)N (4.7-41) and low Ti/Eu (873-2292) ratios and equilibrated with carbonated silicate melt-like compositions. These petrographic and chemical features indicate that the wehrlite was formed by reaction between peridotite and carbonated silicate melts. On the other hand, the Changle melt pocket-bearing peridotite is suggested to have been produced by in-situ melting/breakdown of amphiboles of an amphibole-rich dunite. Low olivine Fo (~89), presence of amphiboles with high (La/Yb)N (~50) and low Ti/Eu (~1070) ratios suggest that such amphibole-rich dunite would have been formed by reaction of peridotite with hydrous alkaline basaltic melts from a carbonated mantle. Our data, combined with previously reported data of the Changle lherzolite xenoliths, unravel a series of mantle metasomatisms by carbonatitic to alkaline melts from carbonated mantle sources. The consistently high 87Sr/86Sr ratios (up to 0.7036) of the clinopyroxenes in both the wehrlites and lherzolites indicate the carbonate components in the mantle sources were derived from the stagnant Pacific slab within the Mantle Transition Zone. This study provides a fresh perspective on the role of deep carbon cycling from subducted oceanic slabs in chemical modification of intracontinental lithospheric mantle through reaction with different types of melts.
DS202204-0548
2022
Geng, X.Zou, Z., Wang, Z., Foley, S., Xu, R., Geng, X., Liu, Y-N., Liu, Y., Hu, Z.Origin of low-MgO primitive intraplate alkaline basalts from partial melting of carbonate-bearing eclogite sources. Hannuoba Geochimica et Cosmochimica Acta, in press available, 53p.Chinaeclogite

Abstract: Alkaline basalts occur widely in intraplate settings and carbonate-bearing mantle sources such as carbonated peridotites are increasingly regarded to play a key role in their formation. Carbonated eclogites, most likely the products of subducted carbonate-bearing altered oceanic crust, are probable alternative ingredients in the mantle sources of many intraplate alkaline basalts, highlighting the importance of the subduction-driven deep carbon cycle. However, this widely proposed hypothesis remains enigmatic because the recognition of low-MgO primitive alkaline basalts predicted by experiments is scarce. Here we show that Cenozoic continental intraplate alkaline basalts occurring above the stagnant oceanic slab in the mantle transition zone beneath the Hannuoba region, eastern China, display geochemical features consistent with their origin as low-degree partial melts of carbonate-bearing eclogites. Their MgO contents correlate positively with CaO, Ba/Th and Ti/Eu, but negatively with Dy/Yb and ?Nd. Remarkably, the most primitive alkaline basalts are characterized by low MgO (<5.25 wt.%), low heavy rare earth elements and Sc contents, low CaO/Al2O3 (<0.41), low Ti/Eu (<3380), but Dy/Yb (>7.1) higher than those of ocean island basalts (OIBs). These features cannot be ascribed to differentiation from high-MgO alkaline basalts because significant amounts of crystallization of clinopyroxene and garnet did not occur during ascent. Differentiation also cannot account for the correlations of time-integrated Sr-Nd isotopes with MgO, Dy/Yb and Ba/Th. Instead, the linear correlations mainly reflect strong interaction between ascending primitive alkaline melts and the lithospheric mantle. The compositions of primitive alkaline basalts reflect the key control of garnet and clinopyroxene in the mantle residue (eclogites), and the Ti, Zr and Hf anomalies further indicate the critical effect of carbonates in the eclogite source. Partial melting of the carbonate-bearing eclogites likely occurred in the uppermost asthenosphere. The production of alkaline basalts with low MgO contents by partial melting of carbonate-bearing eclogite below the peridotite solidus in an intraplate setting has been overlooked and the magmas were instead often considered to be highly evolved. Recycled altered oceanic crust thus may not only cause metasomatism of the deep mantle but may also serve as a direct source of mafic melts. These results on natural rocks support the experiment-based model for subducted altered oceanic crustal material and also indicate its diverse fate in the mantle.
DS201212-0232
2012
Geng, Y.Geng, Y., Du, L., Ren, L.Growth and reworking of the early Precambrian continental crust in the North Chin a Craton: constraints from zircon Hf isotopes.Gondwana Research, Vol. 21, 2-3, pp. 517-529.ChinaMelting
DS202102-0192
2021
Geng, Y.Geng, Y., Du, L., Kuang, H., Liu, Y.Ca. 1.7 Ga magmatism on southwestern margin of the Yangtze block: response to the breakup of Columbia.Acta Geologica Sinica, Vol. 94, 6, pp. 2031-2052.Chinamagmatism

Abstract: This paper presents some data of the Jiaopingdu gabbro and Caiyuanzi granite at the southwestern margin of the Yangtze Block, on the geochemical compositions, zircon LA-ICP-MS U-Pb ages and Hf isotopic data. The Jiaopingdu gabbro gives the age of 1721 ± 5 Ma, the Caiyuanzi granite 1732 ± 6 Ma and 1735 ± 4 Ma, and the Wenjiacun porphyry granite 1713 ± 4 Ma, suggesting nearly contemporaneous formation time of the gabbro and granite. The bimodal feature is demonstrated by the gabbro SiO2 content of 44.64-46.87 wt% and granite 73.81-77.03 wt%. In addition, the granite has high content of SiO2 and Na2O + K2O, low content of Al2O3 and CaO, enriched in REEs (except Eu) and Zr, Nb, Ga and Y, depleted in Sr, implying it belongs to A?type granite geochemistry and origin of within?plate environment. The zircon ?Hf(t) of the granite and gabbro is at the range of 2-6, which is near the 2.0 Ga evolution line of the crust, implying the parent magma of the gabbro being derived from the depleted mantle and a small amount of crustal material, and the parent magma of the granite from partial melting of the juvenile crust and some ancient crustal material at the same time. Compared with 1.8-1.7 Ga magmatism during breakup of other cratons in the world, we can deduce that the Columbia has initially broken since ca. 1.8 Ga, and some continental marginal or intra?continental rifts occurred at ca. 1.73 Ga.
DS1992-1701
1992
Geng YuanshengWu Jianshan, Geng Yuansheng, Tang Lianjiang, Zang AndiRelationship of Diamondiferous kimberlites with tectonic setting of basement in Sino-Korean PlatformRussian Geology and Geophysics, Vol. 33, No. 10, 5p.ChinaStructure, Sino-Korean Platform
DS1995-0892
1995
Genge, M.Jones, A.P., Dobson, D.P., Genge, M.Comment on physical properties of carbonatite magmas inferred from molten salt data, mantle chambers....Geological Magazine, Vol. 132, No. 1, p. 121.GlobalMagma, Carbonatite -silicate
DS201312-0448
2013
Genge, M.Jones, A.P., Genge, M., Carmody, L.Carbonate melts and carbonatites.Reviews in Mineralogy and Geochemistry, Vol. 75, pp. 289-322.MantleCarbonatite
DS1995-0614
1995
Genge, M.J.Genge, M.J., Jones, A.P., Price, G.D.An infrared and Raman study of carbonate glasses: implications for the structure of carbonatite magmas.Geochimica et Cosmochimica Acta, Vol. 59, No. 5, pp. 927-937.GlobalMagma -carbonatite, Mantle metasomatism, Melt, structure
DS1995-0615
1995
Genge, M.J.Genge, M.J., Price, G.D., Jones, A.P.Molecular dynamics simulations of CaCO3 melts -mantle pressure/temperatures: implications for carbonatite.Earth and Planetary Science Letters, Vol. 131, No. 3-4, April pp. 225-238.GlobalCarbonatite
DS1970-0566
1972
Genin, B.L.Molochnov, G.V., Radionov, M.N., Genin, B.L.Use of Dipole Electric-magnetic Sounding in Determining The thickness of Alluvium During Exploration for Beach Diamond Placers in the Region of Anabar Bay.Geofiz. Metody Razved. Arkt., No. 7, PP. 68-73.Russia, YakutiaKimberlite, Geophysics
DS202010-1844
2020
Genish, H.Genish, H., Ganesan, K., Stacey, A., Prawer, S., Rosenbluh, M.Effect of radiation damage on the quantum optical properties of nitrogen vacancies in diamond.Diamond & Related Materials, Vol. 109, 108049, 6p. PdfMantlenitrogen

Abstract: Single crystal diamond (<5?ppm nitrogen) containing native NV centers with coherence time of 150??s was irradiated with 2?MeV alpha particles, with doses ranging from 1012 ion/cm2 to 1015 ion/cm2. The effect of ion damage on the coherence time of NV centers was studied using optically detected magnetic resonance and supplemented by fluorescence and Raman microscopy. A cross-sectional geometry was employed so that the NV coherence time could be measured as a function of increasing defect concentration along the ion track. Surprisingly, although the ODMR contrast was found to decrease with increasing ion induced vacancy concentration, the measured decoherence time remained undiminished at 150us despite the estimated vacancy concentration reaching a value of 40?ppm at the end of range. These results suggest that ion induced damage in the form of an increase in vacancy concentration does not necessarily result in a significant increase in the density of the background spin bath.
DS1996-0510
1996
Genkin, A.D.Genkin, A.D., Evastigneeva, T.L.The Albanian ophiolite hosted ore deposits: after the workshop and fieldtripGeology of Ore Deposits, Vol. 38, No. 2, pp. 176-182AlbaniaOphiolites, Metallogeny
DS201602-0241
2015
Genovese, A.Sokolova, E., Abdu, Y., Hawthorne, F.C., Genovese, A., Camara, F., Khomyakov, A.P.From structure topology to chemical composition. XVIII. Titanium silicates: revision of the crystal structure and chemical formula of Betalomonosovite, a group IV TS-block mineral from the Lovozero alkaline massif, Kola Peninsula.The Canadian Mineralogist, Vol. 53, pp. 401-428.Russia, Kola PeninsulaLovozero Massif

Abstract: The crystal structure of betalomonosovite, ideally Na6?4Ti4(Si2O7)2[PO3(OH)][PO2(OH)2]O2(OF), a 5.3331(7), b 14.172(2), c 14.509(2) Å, ? 103.174(2), ? 96.320(2), ? 90.278(2)°, V 1060.7(4) Å3, from the Lovozero alkaline massif, Kola peninsula, Russia, has been refined in the space group PFormula to R = 6.64% using 3379 observed (Fo > 4?F) reflections collected with a single-crystal APEX II ULTRA three-circle diffractometer with a rotating-anode generator (MoK?), multilayer optics, and an APEX-II 4K CCD detector. Electron-microprobe analysis gave the empirical formula (Na5.39Ca0.36Mn0.04Mg0.01)?5.80 (Ti2.77Nb0.48Mg0.29Fe3+0.23Mn0.20Zr0.02Ta0.01)?4(Si2.06O7)2[P1.98O5(OH)3]O2[O0.82F0.65(OH)0.53]?2, Dcalc. = 2.969 g cm?3, Z = 2, calculated on the basis of 26 (O + F) apfu, with H2O determined from structure refinement. The crystal structure of betalomonosovite is characterized by extensive cation and anion disorder: more than 50% of cation sites are partly occupied. The crystal structure of betalomonosovite is a combination of a titanium silicate (TS) block and an intermediate (I) block. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral) and exhibits linkage and stereochemistry typical for Group IV (Ti + Mg + Mn = 4 apfu) of the TS-block minerals. The I block is a framework of Na polyhedra and P tetrahedra which ideally gives {Na2?4[PO3(OH)][PO2(OH)2]} pfu. Betalomonosovite is an Na-poor OH-bearing analogue of lomonosovite, Na10Ti4(Si2O7)2(PO4)2O4. In the betalomonosovite structure, there is less Na in the I block and in the TS block when compared to the lomonosovite structure. The OH groups occur mainly in the I block where they coordinate P and Na atoms and in the O sheet of the TS block (minor). The presence of OH groups in the I block and in the TS block is supported by IR spectroscopy and bond-valence calculations on anions. High-resolution TEM of lomonosovite shows the presence of pervasive microstructural intergrowths, accounting for the presence of signals from H2O in the infrared spectrum of anhydrous lomonosovite. More extensive lamellae in betalomonosovite suggest a topotactic reaction from lomonosovite to betalomonosovite.
DS1999-0780
1999
Genser, J.Wang, X., Neubauer, F., Genser, J., Yang, W.The Dabie ultra high pressure (UHP) unit, Central China: a Cretaceous extensional allochthon superposed on a Triassic Orogen.Terra Nova, Vol. 10, No. 5, p. 260-67.ChinaTectonics, metamorphism, Dabie
DS1985-0229
1985
Genshaff, I.S.Genshaff, I.S., Satykov, A.J.The Kimberlite Type of Inclusions in Alkaline Basalts of The Dariganga Plateau.Doklady Academy of Sciences AKAD. NAUK SSR., Vol. 282, No. 5, PP. 1200-1205.RussiaPetrography
DS1993-0716
1993
GenshaftIonov, D.A., Dupuy, C., O'Reilly, S.Y., Kopylova, M.G., GenshaftCarbonated peridotite xenoliths from Spitzbergen: implications for trace element signature of mantle carbonate MetasomatismEarth and Planetary Science Letters, Vol. 119, No. 3, September pp. 283-298NorwayMantle Metasomatism, Geochronology
DS1993-0717
1993
GenshaftIonov, D.A., Dupuy, C., O'Reilly, S.Y., Kopylova, M.G., GenshaftCarbonated peridotite xenoliths from Spitsbergen: implications from trace element signature of mantle carbonate MetasomatismEarth and Planetary Science Letters, Vol. 119, No. 3, September pp. 283-298NorwayXenoliths, Mantle Metasomatism
DS1984-0730
1984
Genshaft, I.S.Timofeyev, A.A., Ilupin, I.P., Genshaft, I.S.Spatial Distribution of Ilmenites with Different Content Of magnesium in Yakutian Kimberlites.Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 278, No. 2, PP. 461-464.RussiaBlank
DS1992-0750
1992
Genshaft, V.S.Ilupin, I.P., Genshaft, V.S.On Inter relation of kimberlite chemical composition, size and content Of the comprised olivines.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 326, No. 2, pp. 341-344RussiaMineral chemistry, Olivine, kimberlite
DS1984-0731
1984
Genshaft, Y.S.Timofeyev, A.A., Ilupin, I.P., Genshaft, Y.S.Spatial distribution of ilmenites with varying amounts of manganese in kimberlites from Yakutia.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR (Russian), Vol. 278, No. 2, pp. 461-464RussiaPetrology, Ilmenite
DS1990-0242
1990
Genshaft, Y.S.Brodskaya, S.Y., Sharanova, Z.V., Genshaft, Y.S., Ilupin, I.P.Temperatures of secondary geologic processes in the Yakutia kimberlites evaluated from magneticdata.(Russian)Izvest. Akad. Nauk, SSSR, (Russian), No. 1, January pp. 62-70. ISI# CR 707RussiaGeophysics -magnetics, Alteration
DS1993-0515
1993
Genshaft, Y.S.Genshaft, Y.S.Textures of deep xenoliths as implied by dynamic processes in the earth'slithosphere. (Russian)Fizik Zemli, (Russian), No. 10, October pp. 44-59.RussiaXenoliths, Petrography
DS1993-0516
1993
Genshaft, Y.S.Genshaft, Y.S., Ilupin, I.P.Are olivines in kimberlites phenocrystals or xenocrystals.(Russian)Doklady Academy of Sciences Akad. Nauk., (Russian), Vol. 331, No. 1, July pp. 66-68.RussiaKimberlites, Olivines
DS1994-0804
1994
Genshaft, Y.S.Ilupin, I.P., Genshaft, Y.S.New dat a on differences between kimberlites northeast and northwest field groups of Yakutian Province(Russian)Doklady Academy of Sciences Nauk SSR, (Russian), Vol. 338, No. 2, Sept. pp. 207-210.Russia, YakutiaGeochemistry, Kimberlites
DS1994-0805
1994
Genshaft, Y.S.Ilupin, I.P., Genshaft, Y.S.New dat a on differences between kimberlites northeast and northwest field groups of Yakutian kimberlitic province.(Russian)Doklady Academy of Sciences Nauk, (Russian), Vol. 338, No. 1, Sept. pp. 207-210.Russia, YakutiaKimberlites, Geochemistry
DS1996-0669
1996
Genshaft, Y.S.Ionov, D.A., O'Reilly, S.Y., Genshaft, Y.S., Kopylova, M.Carbonate bearing mantle peridotite xenoliths from Spisbergen: phaserelationships, minerals compositionsContributions to Mineralogy and Petrology, Vol. 125, No. 4, pp. 375-392.NorwayXenoliths, Petrology
DS1996-0775
1996
Genshaft, Y.S.Kopylova, M.G., Genshaft, Y.S., Dashevsk, D.V.Petrology of upper mantle and lower crustal xenoliths from the northwesternSpitsbergen.Petrology, Vol. 4, No. 5, Sept-Oct., pp. 493-518.NorwayXenoliths
DS2000-0330
2000
Genshaft, Y.S.Genshaft, Y.S., Tselmovich, GapeevPicroilmenite: factors determining its compositionDoklady Academy of Sciences, Vol. 373A, No. 6, Aug-Sept. pp.969-73.GlobalMineralogy - picroilmenite
DS2000-0331
2000
Genshaft, Y.S.Genshaft, Y.S., Zlobin, V.L.Eutectic melting in the Earth's crustDoklady Academy of Sciences, Vol. 373, No. 5, June-July, pp.911-13.MantleMelting
DS1983-0248
1983
Genshaft, YU.S.Genshaft, YU.S., Saltykovskiy, A.YA., Vayner, D.I.Crystallization of minerals of the eclogite paragenesis at pressures of 35to 50 kbarDoklady Academy of Science USSR, Earth Science Section, Vol. 273, Nov.-Dec. pp. 115-118RussiaXenoliths, Eclogite
DS1984-0295
1984
Genshaft, YU.S.Genshaft, YU.S., Ilupin, I.P., Rovsha, V.S.A New Discovery of a Graphite Ilmenite Silicate Intergrow thin the Yakutian Kimberlites.Mineral. Zhurn., Vol. 6, No. 2, PP. 55-61.RussiaAlakit, Druzhba, Mir, Sytykan, Monastery, Frank Smith, Stockdale
DS1984-0296
1984
Genshaft, YU.S.Genshaft, YU.S., Ilupin, I.P., Rovsha, V.S.Discovery of a Graphic Ilmenite Silicate Intergrowth in Yakutian Kimberlites.Mineral. Zhur., Vol. 6, No. 2, PP. 55-61.Russia, YakutiaPetrography
DS1984-0297
1984
Genshaft, YU.S.Genshaft, YU.S., Saltykovskiy, A.YA., Vayner, D.I.Generation of potassic mantle magma as inferred from experimental petrologic dataDoklady Academy of Science USSR, Earth Science Section, Vol. 275, March-April pp. 53-55RussiaGenesis, Eclogite
DS1985-0230
1985
Genshaft, YU.S.Genshaft, YU.S., Vayner, D.I., Saltykovskiy.Crystallization of Minerals of Eclogite Paragenesis at Pressures of 35 to 50 Kbar.Doklady Academy of Science USSR, Earth Science Section., Vol. 273, No. 1-6, PP. 115-118.RussiaGarnet, Composition, Diamond Bearing Eclogites
DS1986-0380
1986
Genshaft, Yu.S.Ilupin, I.P., Genshaft, Yu.S.Metasomatic replacement of picroilmenite in kimberlites.(Russian)Mineral Zhon., (Russian), Vol. 8, No. 5, pp. 65-72RussiaMetasomatism, Geochemistry
DS1987-0245
1987
Genshaft, Yu.S.Genshaft, Yu.S., Saltykovskiy, A.Ya.Kimberlite type inclusions in alkalic basalts of the Dariganga plateau, MOngolian People's RepublicDoklady Academy of Sciences Acad. Science USSR Earth SCi. Section, Vol. 282, No. 1-6, pp. 120-125.RussiaKimberlite, Geochemistry
DS1992-1069
1992
Genshaft, Yu.S.Milyutkin, S.A., Genshaft, Yu.S., Saltykovski, A.Ye., KuznetsovaPhysical characteristics of megacrystal high pressure phasesJournal of Geodynamics, Vol. 15, No. 3-4, pp. 169-184.GlobalKimberlite
DS1993-0841
1993
Genshaft, Yu.S.Kopylova, M.G., O'Reilly, Y.S.Y., Genshaft, Yu.S.A geotherm beneath central Mongolia derived from lower crustal upper mantlexenoliths.The Xenolith window into the lower crust, abstract volume and workshop, p. 13.GlobalXenoliths, Geothermometry
DS1994-0806
1994
Genshaft, Yu.S.Ilupin, I.P., Genshaft, Yu.S.The correlation between kimberlite composition and olivine concentration and grain size.Doklady Academy of Sciences USSR, Vol. 327A, Nov. pp. 139-142.Russia, YakutiaKimberlite -olivine, Deposit -Daldyn, Alakit
DS1995-0999
1995
Genshaft, Yu.S.Kopylova, M.G., O'Reilly, S.Y., Genshaft, Yu.S.Thermal state of the lithosphere beneath Central Mongolia: evidence from deep seated xenoliths..Lithos, Vol. 36, No. 3/4, Dec. 1, pp. 243-256.GlobalThermometry, Shavaryn-Saram volcanic centre, Tariat Depression
DS1996-0511
1996
Genshaft, Yu.S.Genshaft, Yu.S., Ilupin, I.P.Olivine in kimberlites: phenocrysts or xenocrystals?Doklady Academy of Sciences, Vol. 336, pp. 22-26.RussiaKimberlite petrology
DS1996-0662
1996
Genshaft, Yu.S.Ilupin, I.P., Genshaft, Yu.S.New dat a on the differences between kimberlites in the northeast and northwest field groups in the Yakutian kimberlite provDoklady Academy of Sciences, Vol. 341A, No. 3, April, pp. 77-82.Russia, YakutiaDiamond composition, Geochemistry
DS1997-1040
1997
Genshaft, Yu.S.Shubina, N.A., Ukhanov, A.V., Genshaft, Yu.S., KolesovTrace and major elements in peridotites beneath northwestern Spitsbergen: acontribution to mantle...Geochemistry International, Vol. 35, No. 1, pp. 17-31.GlobalMantle heterogeneity, Peridotites
DS2001-0898
2001
Genshaft, Yu.S.Pechersky, D.M., Genshaft, Yu.S.Paleomagnetism of the continental lithosphere and the origin of regional magnetic anomalies: review.Russian Journal of Earth Science, Vol. 3, 2, May, pp.MantleGeophysics - magnetics
DS2002-0552
2002
Genshaft, Yu.S.Genshaft, Yu.S., Ilupin, I.P.On genetic classification of chromian spinels in deep seated rocks from continental structures.Russian Journal of Earth Science, Vol. 4, 2, April, pp.RussiaMineralogy - spinels
DS201911-2567
2019
Genske, F.Stracke, A., Genske, F., Berndt, J., Koornneef, J.M.Ubiquitous ultra-depleted domains in Earth's mantle. Azores plumeNature Geosciences, Vol. 12, pp. 851-855.Mantlehot spots, plumes

Abstract: Partial melting of Earth’s mantle generates oceanic crust and leaves behind a chemically depleted residual mantle. The time-integrated composition of this chemically depleted mantle is generally inferred from basalts produced at mid-ocean ridges. However, isotopic differences between oceanic mantle rocks and mid-ocean ridge basalts suggest that mantle and basalt composition could differ. Here we measure neodymium isotope ratios in olivine-hosted melt inclusions from lavas of the Azores mantle plume. We find neodymium isotope ratios that include the highest values measured in basalts, and suggest that melts from ultra-depleted mantle contribute to the isotopic diversity of the erupted lavas. Ultra-depleted melts have exceedingly low preservation potential during magma extraction and evolution due to progressive mixing with melts that are enriched in incompatible elements. A notable contribution of ultra-depleted melts to the Azores mantle plume therefore implies that variably depleted mantle is the volumetrically dominant component of the Azores plume. We argue that variably depleted mantle, sometimes ranging to ultra-depleted compositions, may be a ubiquitous part of most ocean island and mid-ocean ridge basalt sources. If so, Earth’s mantle may be more depleted than previously thought, which has important implications for the rate of mass exchange between crust and mantle, plume dynamics and compositional stratification of Earth’s mantle.Depleted mantle is a volumetrically dominant component of the Azores plume and possibly of oceanic basalt sources more generally, according to neodymium isotope compositions of olivine-hosted melt inclusions from lavas of the Azores mantle plume.
DS201112-0358
2011
Gent, M.Gent, M., Menendez, M., Torano, J., Torno, S.A review of indicator minerals and sample processing methods for geochemical exploration. Mentions kimberlitesJournal of Geochemical Exploration, Vol. 110, 2, pp. 47-60.TechnologyIM, density, magnetic
DS1989-0500
1989
Gent, M.L.Gent, M.L.Regional Phanerozoic anomalies of SaskatchewanSaskatchewan Geological Survey Summary of Investigations for 1989, Report No. 89-4, pp. 162-167SaskatchewanSeismic, magnetics, Pipes
DS1990-0552
1990
Gent, M.R.Gent, M.R., Harper, C.T., Guliov, P., Macdonald, R.Saskatchewan diamonds: a new realityThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 83, No. 939, July p. 115. Abstract (PDA)SaskatchewanBrief overview, Diamond activities
DS1991-0554
1991
Gent, M.R.Gent, M.R.Diamond exploration in Saskatchewan #1Preprint paper given at the The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Annual Meeting, held April 28-30, 1991, 19pSaskatchewanOverview, Diamond exploration
DS1991-0555
1991
Gent, M.R.Gent, M.R.Diamonds in SaskatchewanBritish Columbia Geological Survey, Open File, No. 1991-23, p. 147-157SaskatchewanOverview, Diamonds-exploration
DS1992-0551
1992
Gent, M.R.Gent, M.R.Diamonds and precious gems of the Phanerozoic Basin, Saskatchewan:preliminary investigationSaskatchewan Energy and Mines, Geological Survey, Open File report No. 92-2, 67p. 17 maps approx. $ 80.00SaskatchewanKimberlite pipes, Geophysics, geology
DS1992-0552
1992
Gent, M.R.Gent, M.R.Diamond exploration in Saskatchewan #2The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 85, No. 956, January pp. 64-71SaskatchewanOverview of activities, Historical background material
DS1992-0553
1992
Gent, M.R.Gent, M.R., Kreis, L.K., Gendzwill, D.The Maple Creek structure, southwestern SaskatchewanSaskatchewan Report Summary of Investigations 1992, miscellaneous Report No. 92-4, pp. 204-208SaskatchewanGeophysics -seismics, magnetics, gravity, Structure
DS1992-0628
1992
Gent, M.R.Guilov, P., Gent, M.R.Review of industrial minerals investigations 1992-1993. Kimberlite indicator mineral samplingSaskatchewan Report Summary of Investigations 1992, miscellaneous Report No. 92-4, pp. 197-198SaskatchewanGeochemistry, Indicator minerals, kimberlite sampling
DS1992-1504
1992
Gent, M.R.Swanson, F.J., Gent, M.R.Preliminary results of reconnaissance sampling for diamond indicatorminerals.Saskatchewan Report Summary of Investigations 1992, miscellaneous Report No. 92-4, pp. 199-203.SaskatchewanSampling, garnets, Indicator minerals
DS1993-0517
1993
Gent, M.R.Gent, M.R.Scope of the symposium... overviewMid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 1-6CanadaDiamond exploration
DS1993-0518
1993
Gent, M.R.Gent, M.R.Mineralogical and group classification Program.. for diamond indicatorminerals. ( a listing of other minerals and include Gurney's classification of G9, G10Saskatchewan Energy and Mines -Geological Survey, Data File No. 18, 3 p. text and discSaskatchewanGeochemistry, Indicator mineral application
DS1993-1560
1993
Gent, M.R.Swanson, F.J., Gent, M.R.Results of reconnaissance diamond indicator mineral sampling, Saskatchewan.Mid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 107-116.SaskatchewanGeochemistry, Mineral chemistry
DS1993-1561
1993
Gent, M.R.Swanson, F.J., Gent, M.R.Reconnaissance diamond indicator mineral sampling in Saskatchewan(Saskatchewan Geological Survey).Geological Society of Canada (GSC) Forum abstracts, p. 39. poster abstract.SaskatchewanMineral sampling, Indicators
DS1994-0597
1994
Gent, M.R.Gent, M.R., Czornobay, B.M.Southern gravity compilationSaskatchewan Geological Survey, No. 94-4, pp. 170-171.SaskatchewanGeophysics -gravity
DS1994-0598
1994
Gent, M.R.Gent, M.R., Czornobay, B.M.Composite bouguer gravity map Regin a -Wynyard area. 1: 250, 000Saskatchewan Geological Survey, Map No. 94-4, (13).SaskatchewanGeophysics -gravity, Map -Bouguer
DS1994-1725
1994
Gent, M.R.Swanson, F.J., Gent, M.R.Results of reconnaissance sampling for kimberlite and lamproite indicatorminerals, Saskatchewan #1Geological Survey of Canada Open Forum January 17-19th. Abstracts only, p. 37.SaskatchewanGeochemistry, Indicator minerals
DS1994-1726
1994
Gent, M.R.Swanson, F.J., Gent, M.R.Preliminary results of reconnaissance sampling for diamond indicator minerals in the exposed Precambrian.Saskatchewan Geological Survey, No. 94-4, pp. 159-169.SaskatchewanGeochemistry, sampling, Diamond indicators
DS1994-1727
1994
Gent, M.R.Swanson, F.J., Gent, M.R.Distribution of kimberlite and lamproite indicator minerals, northernSaskatchewan.Saskatchewan Geological Survey, Map No. 94-4, (9).1: 1, millionSaskatchewanMap -distribution kimberlite, Map -distribution lamproite
DS1995-0616
1995
Gent, M.R.Gent, M.R., Swanson, F.J.Phanerozoic anomalies and regional diamond indicator mineral sampling studies.Geological Survey of Canada (GSC) Open File, No. 3119, pp. 95-98.SaskatchewanGeochemistry
DS2000-0558
2000
GenteLe Gall, B., Tiercelin, J.J., Richert, Gente, SturchioA morphotectonics study of an extensional fault zone in a magma rich rift:the Baringo trachyte fault systemTectonophysics, Vol. 320, No. 2, May 15, pp. 87-106.KenyaTectonics - central Kenya Rift
DS1994-0349
1994
Gente, P.Coussement, C., Gente, P., Rolet, J., Tiercelin, J.J.The North Tanganyika hydrothermal fields, East African Rift system: their tectonic control, rift segregationTectonophysics, Vol. 237, pp. 155-173.Democratic Republic of CongoTectonics, East African Rift
DS1860-0183
1872
Genth, F.A.Genth, F.A.Mineral Resources of North CarolinaJournal of the Franklin Institute, Vol. 93, PP. 48-61; PP. 114-130.United States, North CarolinaDiamond Occurrence
DS1860-0245
1875
Genth, F.A.Genth, F.A.Minerals of North Carolin a (1875)North Carolina Geological Survey Report, PP. 53-58. ALSO: Journal of FRANKLIN Institute Nov. and Dec.United States, North CarolinaDiamond Occurrence
DS1860-0364
1881
Genth, F.A.Genth, F.A.Minerals of North Carolin a (1881)Raleigh: P.m. Hale And Edwards, 122P.United States, North CarolinaDiamond Occurrence
DS1860-0466
1885
Genth, F.A.Genth, F.A.Minerals of North Carolin a (1885)Raleigh: P.m. Hale And Edwards, 128P.United States, North CarolinaDiamond Occurrence
DS1860-0700
1891
Genth, F.A.Genth, F.A.Diamond, 1891United States Geological Survey (USGS) Bulletin., No. 74, 119P.United States, North CarolinaDiamond Occurrence
DS1993-0519
1993
Gentry, D.W.Gentry, D.W., Jarnigan, L.Environmental aspects an increasing part of international mining projectsMining Engineering, Vol. 45, No. 8, August pp. 1009-1011GlobalEconomics, Environmental costs
DS1991-0556
1991
GeobotanyGeobotanyEvaluation of geobotanical remote sensing as an aid to mineral explorationin northeastern Ontario #1Ontario Geological Survey Open File, No. 5757, 22pOntarioBeswick, A.E., Beckett, P.J., Courtin, G.M., Tapper, G.O, Remote sensing
DS1986-0282
1986
GeoBulletinGeoBulletinVisit to Premier diamond mineGeoBulletin, Vol. 29, No.4, pp. 24-25South AfricaDeposit
DS1987-0246
1987
GeoBulletinGeoBulletinDifferent windows to the mantle: a lecture by Prof. Duff GoldGeoBulletin, Vol. 30, No. 3, Third Quarter, pp. 20-21South AfricaBrief overview- given in South Africa
DS1988-0245
1988
GeoBulletinGeoBulletinSir Ernest Oppenheimer- a champion of geological research andexplorationGeoBulletin, Vol. 31, No. 1, p. 49GlobalBlank
DS1988-0246
1988
GeoBulletinGeoBulletinDiamonds and Harry Oppenheimer HouseGeoBulletin, Vol. 31, No. 1, pp. 45-46South AfricaOverview
DS1992-0554
1992
Geocarto International CentreGeocarto International CentreMaps and books... see listGeocarto International Centre, ChinaBook - list and maps, Geology, geophysics, mineral resources, metallogeny
DS1992-0555
1992
GeochautauquaGeochautauquaEnergy and mineral resource assessments- how are they done? who are they done for? how effective are they?note transcript from meeting held Oct.1989...Nonrenewable Resources, Vol. 1, No. 1, Spring pp. 5-39United StatesLand use policy, Legal -mineral resources
DS1999-0243
1999
Geochemical Evolution and Metallogeny of ContinentsGeochemical Evolution and Metallogeny of ContinentsEvent signatures - tracing crustal growth with detrital zirconsGemoc Annual Report, pp. 26-7.AustraliaCraton - Yilgarn, Geochronology
DS1999-0244
1999
Geochemical Evolution and Metallogeny of ContinentsGeochemical Evolution and Metallogeny of ContinentsWhat is the origin of the diamonds from eastern Australia?Gemoc Annual Report, pp. 24-5.Australia, New South Wales, Urals, California, KalimantanDiamond genesis, Subduction
DS1999-0245
1999
Geochemical Evolution and Metallogeny of ContinentsGeochemical Evolution and Metallogeny of ContinentsXenoliths from the Kerguelen Islands - mantle metasomatism and continent formation.Gemoc Annual Report, pp. 28-9.Indian Ocean, Kerguelen IslandsXenoliths - research
DS1999-0246
1999
Geochemical Evolution and Metallogeny of ContinentsGeochemical Evolution and Metallogeny of ContinentsSulphides - a shining tracer of lithosphere evolutionGemoc Annual Report, pp. 18-19.MantleXenolith - research - brief
DS1999-0247
1999
Geochemical Evolution and Metallogeny of ContinentsGeochemical Evolution and Metallogeny of ContinentsCarbonatites and kimberlites - melt inclusions from deep lithosphere ( Lacde Gras xenoliths).Gemoc Annual Report, pp. 18-19.Northwest TerritoriesXenolith - research - brief
DS1990-0553
1990
Geochemical SocietyGeochemical SocietyV.M. Gold schmidt Conference program and abstracts held May 2-4, 1990 in Baltimore MarylandGeochemical Society, 100pGlobalAbstracts, Extracted ones listed sep
DS2003-0455
2003
Geochimica et Cosmochimica ActaGeochimica et Cosmochimica ActaNitrogen recycling in subduction zones: a strong geothermal controlGeochimica et Cosmochimica Acta, Vol. 67, No. 18, pp. 51-100.MantleIssue - subduction zones, geochemistry
DS200412-0647
2003
Geochimica et Cosmochimica ActaGeochimica et Cosmochimica ActaNitrogen recycling in subduction zones: a strong geothermal control.Geochimica et Cosmochimica Acta, Vol. 67, no. 18, pp. 51-100.MantleIssue - subduction zones, geochemistry
DS1994-0599
1994
GeochroniqueGeochroniqueReservoirs magmatiques..short papers in frenchGeochronique, No. 49, pp. 16-24GlobalStructure, PGM., Convection, ophiolite, mafics, ultramafics
DS2001-0365
2001
GeochroniqueGeochroniqueLe diamant...... layman's overview of diamond, exploration, genesis, uses etc. in FRENCHGeochronique, No. 77, pp. 11-27.GlobalDiamond - genesis, Overview for public
DS200812-0393
2008
Geodinamica ActaGeodinamica ActaMagnification of mantle resonance as a cause of tectonics.Geodinamica Acta, Vol. 20, 6, pp. 369-384.MantleTectonics
DS2001-0366
2001
Geodrilling InternationalGeodrilling InternationalCanadian drilling contractors... overviewGeodrilling International, March, pp. 4-10.CanadaDrilling - mining, contractors, overview, technology
DS202106-0939
2021
Geoffroy, L.Guan, H., Geoffroy, L., Xu, M.Magma-assisted fragmentation of Pangea: continental breakup initiation and propagation.Gondwana Research, Vol. 96, pp. 56-75. pdfMantlemagmatism

Abstract: Pre-magmatic continental extension often precedes the major magmatic expulsion of large igneous provinces (LIPs). However, the cause-and-effect relationship between pre-magmatic rifting and the extrusion of large amount of magma is controversial. It remains unclear whether magmatism arises as a consequence of passive rifting or whether it is related to active upwelling of the mantle. In addition, the relationship between the pre-magmatic stages and the final breakup, with the onset of conjugate passive margins, is ambiguous. In this study, we compiled available data from six LIPs (Central Atlantic, Karoo, Parana-Etendeka, Deccan, North Atlantic, and Afar igneous provinces) that successively occurred during the fragmentation of Pangea and found that pre-magmatic rift trends may show a high obliquity or even be orthogonal with respect to the future passive margins. We conclude that syn-magmatic rifts should not be directly correlated, both structurally and dynamically, to the ancient pre-magmatic rift phase. Furthermore, following the breakup of a supercontinent, seafloor spreading usually initiates within volcanic passive margins (VPMs) and then propagates away to create non-volcanic passive margins (NVPMs) as a consequence of the consumption and cooling of a sub-lithospheric positive thermal anomaly. Major transform faults often exist between VPMs and NVPMs, acting as a mechanical barrier to mantle melting and magmatism transportation.
DS200712-0355
2007
GeoforumGeoforumTheme issue: geographies of generosity. Some references cited separately.Geoforum, Vol. 38, 6, Nov. pp. 1053-1344.GlobalEconomics
DS200812-0394
2008
Geoger, C.A.Geoger, C.A.Silicate garnet: a micro to macroscopic (re)view.American Mineralogist, Vol. 93, 2-3, pp. 360-372.TechnologyGarnet
DS201212-0471
2012
Geoger, C.A.Milani, S., Nestola, F., Angel, R.J., Pasqual, D., Geoger, C.A.Equation of state of almandine and implications for diamond geobarometry.emc2012 @ uni-frankfurt.de, 1p. AbstractMantleDiamond inclusions
DS1989-0501
1989
Geoindustria State EnterpriseGeoindustria State EnterpriseExploration and /or development assistance concerning heavymineralprospectingGeoindustria State Enterprise, Outline of course held Jan. 1989 Prague, 10p. Database # 17910CzeckoslovakiaGeochemistry, Heavy Minerals
DS1989-0502
1989
Geoindustria State EnterpriseGeoindustria State EnterpriseExploration and/or development assistance concerning heavymineralprospectingGeoindustria State Enterprise, Prague Czechoslovakia, 10pGlobalGeochemistry, Application of Prospectin
DS1991-0557
1991
Geol. Society of AmericaGeol. Society of AmericaRock color chartGeological Society of America, RC001 16p. plus chart $ 20.00 United StatesGlobalRock color chart, Fieldwork
DS1990-0554
1990
Geol. Society of AustraliaGeol. Society of AustraliaGondwana: terranes and resources, Tenth Australian Geological Convention.Held Feb. 4-9, Hobart TasmaniaGeological Society of Australia Abstracts, No. 25, 319pAustraliaSection A16 Magmas, gemstones and the mantle, Seperate listings
DS2003-0456
2003
Geological AbstractsGeological AbstractsGetting the most out of our diamonds: Namibia, De Beers and the arrival of Lev LevievGems & Gemology, Vol. 39, Winter, p. 352.NamibiaBlank
DS2003-0457
2003
Geological AbstractsGeological AbstractsJurisdiction over offshore diamond mining. L. E. Moller, Journal of Energy and NaturalGems & Gemology, Vol. 39, Winter, p. 361.NamibiaBlank
DS2003-0458
2003
Geological AbstractsGeological AbstractsSierra Leone diamond sector financial constraints study. U.S. Agency for InternationalGems & Gemology, Vol. 39, Winter, p. 354.Sierra LeoneBlank
DS200412-0648
2003
Geological AbstractsGeological AbstractsJurisdiction over offshore diamond mining. L. E. Moller, Journal of Energy and Natural resources Law, Vol. 21, 2, 2003, pp. 168-Gems & Gemology, Vol. 39, Winter, p. 361.Africa, NamibiaNews item - policy, legal
DS200412-0649
2003
Geological AbstractsGeological AbstractsSierra Leone diamond sector financial constraints study. U.S. Agency for International Development Cooperative agreement 636-A-0Gems & Gemology, Vol. 39, Winter, p. 354.Africa, Sierra LeoneNews item - policy, legal
DS200412-0650
2003
Geological AbstractsGeological AbstractsGetting the most out of our diamonds: Namibia, De Beers and the arrival of Lev Leviev. Institute of Public Policy Research, BrieGems & Gemology, Vol. 39, Winter, p. 352.Africa, NamibiaNews item - policy, legal
DS201112-0359
2011
Geological Association of CanadaGeological Association of CanadaMountain Pass post meeting field trip at the Ottawa 2011 conference.GAC-MAC Annual Meeting May, United States, CaliforniaCarbonatite, field trip
DS1993-0520
1993
Geological Association of Canada (GAC)Geological Association of Canada (GAC)Evolution of the western Interior Basin #1Geological Association of Canada (GAC), Special Paper 39CanadaBook -ad, Basin -Western Interior Canada
DS1996-0512
1996
Geological Association of Canada (GAC)Geological Association of Canada (GAC)Undersaturated alkaline rocks -mineralogy, petrogenesis economicpotential.Mineralogical Association of Canada (MAC) Short Course, May 1996, May 24-26th.GlobalShort course -ad Mineralogical Association of Canada (MAC) May 96, Alkaline rocks
DS1990-0555
1990
Geological Publishing HouseGeological Publishing HouseMineral deposits of ChinaGeological Publishing House, Beijing, 360p. approx. United States 80.00ChinaCopper, lead zinc, antimony, molybdenuM., Book -table of contents
DS1992-0556
1992
Geological Publishing HouseGeological Publishing HouseMineral deposits of China. also platinumGeological Publishing House, Beijing, 350pChinaBauxite, nickel, mercury, tin, tungsten, gold, silver, Book -table of contents
DS1987-0247
1987
Geological Society of AmericaGeological Society of AmericaMagnetic anomaly map of North AmericaG.s.a. Dnag Publ, 1:5, 000, 000 $ 23.20 United StatesNorth AmericaGeophysics, Magnetics
DS1993-0521
1993
Geological Society of AmericaGeological Society of AmericaAsia: a continent built and assembled over the past 500 million yearsGeological Society of America continuing education manual, 260pGlobalBook -table of contents, Craton
DS1993-0522
1993
Geological Society of AmericaGeological Society of AmericaContaminant hydrogeology; practical monitoring, protection, and cleanupGeological Society of America Continuing education manual, 373pUnited StatesBook -table of contents, Hydrogeology -environment
DS1995-0617
1995
Geological Society of AmericaGeological Society of AmericaAndes to the Amazon: mineral wealth of a continentGsa Annual Meeting Abstracts Only, GlobalAbstracts
DS2001-0367
2001
Geological Society of AmericaGeological Society of AmericaThe Geological map of North America. First since 1949Gsa Dnag, in pressNorth America, United States, Canada, MexicoMap - ad, Map compilation
DS200612-0439
2005
Geological Society of AmericaGeological Society of AmericaGlossary of Geology. Fifth edition. 40,000 entries ( 3600 new terms).Geosociety.org, TechnologyBook - glossary
DS200812-0395
2008
Geological Society of AmericaGeological Society of AmericaGeologic map of North America.geosociety.org, CSM001R $ 35.00United States, CanadaMap - geology
DS1990-0556
1990
Geological Society of AustraliaGeological Society of AustraliaGondwana: terranes and resourcesGeological Society of Australia Tenth Australian Geol. Convention, held Feb., 400p. AbstractsAustraliaVolcanics, Sedimentation, Geophysics, Models, Mafics, Precambrian gold, Structure, Fault, Tasman Fold belt
DS1990-0557
1990
Geological Society of AustraliaGeological Society of AustraliaR.L. Stanton Symposium: new frontiers in ore deposit and explorationstudies.Held in conjunction with theTenth. Australian Geol. ConventionGeological Society of Australia Tenth Australian Geol. Convention, held Feb., pp. 305-315. AbstractsGlobalModels/overviews
DS1994-0600
1994
Geological Society of AustraliaGeological Society of AustraliaGeoscience Australia -1994 and beyondGeological Society of Australia Abstracts, No. 37, 530p. approx. $ 80.00AustraliaBook -table of contents, Geochemistry, laterites, metallogeny
DS1997-0390
1997
Geological Society of AustraliaGeological Society of AustraliaNew developments in research for ore deposit explorationGeological Society of Australia, No. 44, abstracts, 80p. approx. $ 55.00AustraliaTable of contents, Ore deposit research
DS2001-0368
2001
Geological Society of AustraliaGeological Society of AustraliaMineralization, alteration and magmatism in the eastern fold belt Mount Isa Block and giant hdyrothermal system and iron stone copper gold Cloncurry district.Geological Society of Australia, No. 5, 140p.AustraliaBook - table of contents, Deposit - Mount Isa, Clonclurry
DS200612-0440
2006
Geological Society of India JournalGeological Society of India Journal10 carat synthetic diamond.Journal of the Geological Society of India, Vol. 68, 1, p. 151. ( 1/4 p.)IndiaDiamond synthesis
DS200612-0441
2006
Geological Society of India JournalGeological Society of India JournalGlaciers and diamonds.Journal of the Geological Society of India, Vol. 68, 1, p. 150. ( 1 p.)IndiaGeomorphology
DS200612-0442
2006
Geological Society of India JournalGeological Society of India JournalGroup discussion on Indian dykes.Journal of the Geological Society of India, Vol. 68, 1, p. 151. ( 1/4 p.)IndiaLamprophyre
DS1994-0601
1994
Geological Society of NamibiaGeological Society of NamibiaProterozoic crustal and metallogenic evolutionGeological Society of Namibia, August 29 to Sept. 1, 1994NamibiaConference, Metallogeny
DS1994-0602
1994
Geological Society of NamibiaGeological Society of NamibiaProterozoic crustal and metallogenic evolution.. conferenceNamibia Geological Society, NamibiaCrust and metallogeny Conference, August 1994
DS1992-0557
1992
Geological Society of NevadaGeological Society of NevadaWalker Lane Symposium, structure, tectonics and mineralizationGeological Society of Nevada, 250p. $ 35.00 United StatesNevadaTectonics, Metallogeny
DS1994-0603
1994
Geological Society of South AfricaGeological Society of South AfricaMinerals of South Africa #1Geological Society of South Africa, 352p. approx. $ 120.00South AfricaMinerals of South Africa, Book -ad
DS200712-0356
2007
Geological Society of South AfricaGeological Society of South AfricaDiamonds in Kimberley Symposium.GSSA Kimberley Diamond Symposium and Trade Show provisional programme, August 23, 24.Africa, South AfricaConference
DS201804-0692
2018
Geological Society of South AfricaGeological Society of South AfricaSAMREC/SAMVAL Compliance and JSE reporting meetings… program T. Marshallgssaconferences.co.za /compliance -jse-reporting, June 28,29 thAfrica, South Africadiamond resource and reserve reporting

Abstract: This two-day Workshop (28th and 29th June 2018) comprises an introduction to the SAMREC and SAMVAL Codes, and JSE Reporting. This course is aimed at geologists, mining engineers and other technical specialists, who include sign-off as Competent Persons ("CPs") or Competent Valuators ("CVs") in their job description. Day one focuses on the basics of the SAMREC and SAMVAL Codes, and concentrates on the requirements for CPs who compile documents, specifically Competent Persons Reports and Integrated Annual Reports, for companies listed on the Johannesburg Stock Exchange (applicable primarily to Solid Minerals). Day two focuses on the Section 12 Listing rules applicable to both the Main Board and the Alt-X as well as the requirements of SAMREC and SAMVAL, highlighting some of the issues experienced by CPs over the years as well as some of the updated requirements as a result of the implementation of the 2016 SAMREC/SAMVAL Codes. An introduction to the JSE Readers Panel and a discussion of some of the on-going compliance issues identified by the panel.
DS1991-0558
1991
Geological Society of the (CIM)Geological Society of the (CIM)The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Annual Field ConferenceGeological Society of the The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) to be held Sept. 5-13, 1991 in, SaskatchewanGold, base metals, diamonds, technology, Conference
DS1989-0503
1989
Geological Society of ZimbabweGeological Society of ZimbabweA field meeting on the Archean-Proterozoic transition.held Sept. 11-22, 1989. Program and abstractsInternational Geological Correlation Programme (IGCP) Project 217, Geological Society Zimbabwe, 50p. Database # 18183ZimbabweArchean, Greenstone belt
DS1997-0391
1997
Geological Society of ZimbabweGeological Society of ZimbabweIntraplate magmatism and tectonics of southern AfricaZimbabwe Geol. Society, ZimbabweConference - Sept, 10-12, Magmatism, tectonics
DS1860-0014
1865
Geological Survey of CanadaGeological Survey of CanadaQuebec DiamondsGeological Survey of Canada REPORT of PROGRESS 1863, MONTREAL: DAWSON BROS. Publishing 938P.Canada, QuebecDiamond Occurrence
DS1860-0396
1883
Geological Survey of CanadaGeological Survey of CanadaProspects of Finding DiamondsGeological Survey of Canada, No. R 1085Canada, OntarioDiamond Occurrence
DS1860-0577
1888
Geological Survey of CanadaGeological Survey of CanadaPrecious Stones, Gems and Decorative Stones in Canada and British america.Geological Survey of Canada Annual Report FOR 1887, PT. 3, PP. 65-80.Canada, United StatesDiamond Occurrence
DS1989-0504
1989
Geological Survey of CanadaGeological Survey of CanadaPrincipal mineral areas of Canada : 39th. edition 1989G.s.c. Map 900a, 39th. Edition, 1: 10, 000, 000 $ 7.50CanadaMap, Mineral areas
DS1989-0505
1989
Geological Survey of CanadaGeological Survey of CanadaDigital data, high resolution aeromagnetic survey of Lake Superior. Flown June -Sept. l987Geophysical Data Centre, Geological Society of Canada (GSC) 1 Observatory Cres. Ottawa 613-995- 5326, OntarioGlobalLake Superior
DS1991-0559
1991
Geological Survey of CanadaGeological Survey of CanadaGravity-bouguer anomaly mapsGeological Survey of Canada, Maps $ 5.00 eachCanadaGeophysics -bouguer gravity, Geophysics -magnetics
DS1991-0560
1991
Geological Survey of CanadaGeological Survey of CanadaTRITER: a gravitational terrain correction program for IBM compatible personal computersAshley Reprod, Geological Society of Canada (GSC) Open File, No. 1834, $ 10.00GlobalComputer, Program -TRITER.
DS1991-0561
1991
Geological Survey of CanadaGeological Survey of CanadaAirborne geophysical survey of the Snow Lake area, ManitobaGeological Survey of Canada Open File, No. 2300, maps 1: 250, 000 $ 217.50ManitobaGeophysics, Snow Lake area
DS1993-0523
1993
Geological Survey of CanadaGeological Survey of CanadaGravity -bouguer anomalies Peace River, AlbertaGeological Survey of Canada Map, No. NO-11-GR (BA), 1: 1, 000, 000 approx. $ 5.20AlbertaGeophysics -gravity, Bouguer map
DS1993-0524
1993
Geological Survey of CanadaGeological Survey of CanadaRelease of high resolution aeromagnetic total field survey of the Cypress Hills area, AlbertaGeological Survey Canada Open File, No. 2588, 1:100, 000 6 sheets $ 60.00AlbertaGeophysics -magnetics, Cypress Hills area
DS1993-0525
1993
Geological Survey of CanadaGeological Survey of CanadaCurrent research Part b: Interior plains and Arctic CanadaGeological Survey of Canada, Report of Activities, Paper No. 93-1B, 70pBathurst Island, Arctic, Northwest Territories, AlbertaBook -table of contents, Report of activities
DS1993-0526
1993
Geological Survey of CanadaGeological Survey of CanadaBedrock geological map of Central High Lake greenstone belt, District ofMackenzie, Northwest TerritoriesGeological Survey Canada Open File, No. 2547, 1:100, 000 $ 15.00Northwest TerritoriesBedrock map, Greenstone belt
DS1993-0527
1993
Geological Survey of CanadaGeological Survey of CanadaCurrent research Part C: Canadian shieldGeological Survey of Canada, Report of Activities, Paper No. 93-1C, 366pNorthwest Territories, Alberta, SaskatchewanBook -table of contents, Report of activities
DS1993-0528
1993
Geological Survey of CanadaGeological Survey of CanadaYukon and Northwest territories bouguer gravity anomaly map. NTS95, 96, 105, 106.Geological Survey of Canada Open File, No. 2733, 1: 1, 000, 000 colour $ 25.00Northwest Territories, YukonGeophysics -gravity, Map
DS1993-0529
1993
Geological Survey of CanadaGeological Survey of CanadaRelease of multiparameter profile line dat a for an electromagnetic/magnetic survey in the Blake River Syncline area, Cochrane and Timiscaming DistrictsGeological Survey Canada Open File, No. 2460, 35 microfiche $ 22.00OntarioGeophysics, Data release
DS1993-0530
1993
Geological Survey of CanadaGeological Survey of CanadaNorth Battleford, Saskatchewan aeromagnetic digital dataGeological Survey Canada Open File, No. 2677, 1 map 1: 500, 000 in colour $ 50.00SaskatchewanMap, Geophysics -aeromagnetics
DS1993-0531
1993
Geological Survey of CanadaGeological Survey of CanadaGravity -bouguer anomalies Lake Athabasca, Alberta-SaskatchewanGeological Survey of Canada Map, No. NO-12-GR (BA), 1: 1, 000, 000 approx. $ 5.20Saskatchewan, AlbertaGeophysics -gravity, Bouguer map
DS1994-0604
1994
Geological Survey of CanadaGeological Survey of CanadaBouguer gravity anomaly map of northern British Columbia, Yukon and Northwest TerritoriesGeological Survey of Canada Open File, No. 2930, 1: 2, 000, 000British Columbia, Yukon, Northwest TerritoriesGeophysics -gravity, Map
DS1994-0605
1994
Geological Survey of CanadaGeological Survey of CanadaThe seismicity map of Canada 1994Geological Survey of Canada, Map MCR 4171E approx. $ 13.00CanadaMap, Geophysics -seismics
DS1994-0606
1994
Geological Survey of CanadaGeological Survey of CanadaReview of Geological Society of Canada (GSC) activities related to diamonds. Abstracts from Geological Society of Canada (GSC) personnel involved in diamond related projectsGeological Survey of Canada, Abstracts Oct. 27, 48p.CanadaOverview, Geological Society of Canada (GSC) activities/projects
DS1994-0607
1994
Geological Survey of CanadaGeological Survey of CanadaGeoanalysis 90 : an international symposium on the analysis of geologicalmaterialsGeological Survey of Canada Bulletin, No. 451, 170pGlobalChemical analysis, determinations, Table of contents
DS1994-0608
1994
Geological Survey of CanadaGeological Survey of CanadaGeneralized geological map of the world and linked databasesGeological Survey of Canada Open File, No. 2915, 1: 35, 000, 000 CD-ROM approx. $ 15.00GlobalMap, Computer -CD-ROM.
DS1994-0609
1994
Geological Survey of CanadaGeological Survey of CanadaCoronation Gulf gravity dataGeological Survey of Canada Open File, Northwest TerritoriesGeophysics -gravity, Open file
DS1995-0618
1995
Geological Survey of CanadaGeological Survey of CanadaRadiogenic age and isotopic studiesGeological Survey of Canada, Paper 1995-F, No. 8, 170pAlberta, Northwest Territories, saskatchewan, OntarioBook -Table of contents, Radiogenic age, geochronology
DS1995-0619
1995
Geological Survey of CanadaGeological Survey of CanadaCurrent research Cordillera and Pacific marginGeological Survey of Canada, Paper 1995-A, 180pBritish Columbia, Yukon, AlbertaBook -Table of contents, Current activities
DS1995-0620
1995
Geological Survey of CanadaGeological Survey of CanadaCurrent research Interior plains and Arctic CanadaGeological Survey of Canada, Paper 1995-B, 160GlobalBook -Table of contents, Current activities
DS1995-0621
1995
Geological Survey of CanadaGeological Survey of CanadaLake Superior map setGeological Survey of Canada map, NL 16/17G $ 20.00OntarioMap, Geotectonics
DS1995-0622
1995
Geological Survey of CanadaGeological Survey of CanadaCurrent research Canadian shieldGeological Survey of Canada, Paper 1995-C, 270pOntario, Northwest Territories, Baffin Island , ManitobaBook -Table of contents, Current activities
DS1995-0623
1995
Geological Survey of CanadaGeological Survey of CanadaInvestigations by Geological Society of Canada (GSC) and Saskatchewan joint ventureGeological Survey of Canada, Open file 3119, 302pSaskatchewanPrecambrian shield margin, Flin Flon, Snake Rapids, Missi Island, Amisk, Hanson Lake
DS1996-0513
1996
Geological Survey of CanadaGeological Survey of CanadaReport of activities #1Geological Survey of Canada, No. 1996-B, 90pAlberta, saskatchewan, Northwest TerritoriesStructure, Mineral exploration, Arctic Islands
DS1996-0514
1996
Geological Survey of CanadaGeological Survey of CanadaReport of activities #2Geological Survey of Canada, No. 1996-C, 205pNorthwest Territories, Baffin Island, Manitoba, SaskatchewanLamprophyre, Back River volcanics, Gravity, Sleepy Drag, Dragon, Stratiform, sedex uranium, copper, structure
DS1997-0392
1997
Geological Survey of CanadaGeological Survey of CanadaExploring for minerals in Alberta: 1992-1995Geological Society of Canada (GSC) Bulletin, No. 500, approx. $ 55.00AlbertaBook - table of contents see Nov. 481-2
DS1998-0488
1998
Geological Survey of CanadaGeological Survey of CanadaAlberta coloured shaded relief map of magnetic anomaliesGeological Survey of Canada Open File, 1:1, 000, 000AlbertaGeophysics - magnetics
DS1998-0489
1998
Geological Survey of CanadaGeological Survey of CanadaRelease of high resolution aeromagnetic total field survey of central Alberta Phase IIIGeological Survey of Canada Open File, No. 3237, 1: 250, 000AlbertaGeophysics - magnetics
DS1998-0490
1998
Geological Survey of CanadaGeological Survey of CanadaRelease of high resolution aeromagnetic total field survey of BaffinIsland, northwest Territories. Phase II.Geological Survey of Canada (GSC) Open File, No. 3496, 28 sheets $20.00 eachNorthwest Territories, Baffin IslandGeophysics - magnetics
DS1998-0491
1998
Geological Survey of CanadaGeological Survey of CanadaCurrent research 1998-C Canadian ShieldGeological Survey of Canada, approx. $ 50.00Northwest Territories, saskatchewan, Ontario, QuebecBook - table of contents
DS1998-0492
1998
Geological Survey of CanadaGeological Survey of CanadaRelease of high resolution aeromagnetic total field survey of VictoriaIsland, northwest Territories. Phase 1.Geological Survey of Canada (GSC) Open File, No. 3368, 9 sheets $20.00 eachNorthwest Territories, Victoria IslandGeophysics - magnetics
DS1998-0493
1998
Geological Survey of CanadaGeological Survey of CanadaCurrent research 1998-D Eastern CanadaGeological Survey of Canada, approx. $ 50.00Quebec, Appalachia, New BrunswickBook - table of contents
DS1998-0494
1998
Geological Survey of CanadaGeological Survey of CanadaCurrent research 1998-A Cordillera and Pacific MarginGeological Survey of Canada, approx. $ 50.00Yukon, Northwest TerritoriesBook - table of contents
DS2003-0459
2003
Geological Survey of CanadaGeological Survey of Canada1 Km grid of magnetic dat a for Canadahttp://gdcinfo.agg.nrcan.gc.ca/products/can.grid/index_e.html, CanadaGeophysics - magnetic grid
DS200412-0651
2003
Geological Survey of CanadaGeological Survey of Canada1 Km grid of magnetic dat a for Canada.gdcinfo.agg.nrcan.gc.ca, CanadaGeophysics - magnetic grid
DS200512-0336
2005
Geological Survey of CanadaGeological Survey of CanadaHigh resolution maps of the shaded residual total magnetic field and shaded magnetic first derivative with Keating coefficients Boothia Peninsula, Nunavut.Geological Survey of Canada Open File, OF 4897-4918 $ 15.00 22 maps @ 15.00 eachCanada, NunavutGeophysical maps
DS200612-0443
2006
Geological Survey of CanadaGeological Survey of CanadaAll about the Geological Survey of Canada ( with humour).collectionscanada.ca, CanadaHistory
DS1991-0562
1991
Geological Survey of FinlandGeological Survey of FinlandCurrent research 1989-1990Geological Survey of Finland, Special Paper, No. 12, 240pFinlandCurrent activities, Table of contents
DS1998-0495
1998
Geological Survey of FinlandGeological Survey of FinlandList of guidebooks availableGeological Survey of Finland, FinlandGuidebooks - from 4th. biennial, Listing of books and costs
DS2001-0369
2001
Geological Survey of FinlandGeological Survey of FinlandGeological map of the Fennoscandian shield. email [email protected]Geological Survey of Finland, Finland, Fennoscandia, Kola PeninsulaMap - ad
DS200612-0444
2006
Geological Survey of FinlandGeological Survey of FinlandResults from reconnaissance scale heavy mineral survey for kimberlitic minerals. Eastern FIn land - new area.Geological Survey of Finland, Oct. 15,Europe, FinlandGeochemistry - survey
DS200812-0396
2008
Geological Survey of IndiaGeological Survey of IndiaMineral finds..... one long paragraph on diamonds.Glimpses of Geoscience Research in India, The Indian report to IUGS 2004-08, p. 292.IndiaDiamond occurrences - brief
DS201012-0232
2004
Geological Survey of IndiaGeological Survey of IndiaDiamonds in India. 75p detailed prospects and projects in India. Divided into two sections Madhya Pradesh and Andhra Pradesh and Karnataka.Geological Survey of India, pp. 2-7 overview pp. 9-33 Madhya and pp. 35-75 Andhra., 75p. CDIndia, Madhya Pradesh, Andhra Pradesh, KarnatakaDiamond localities and prospects
DS201312-0304
2011
Geological Survey of IndiaGeological Survey of IndiaDetailed information dossier on diamond in India.Geological Survey of India, pp. 45-140.IndiaOverview and details on Central, Eastern, Southern provinces
DS201312-0305
2011
Geological Survey of IndiaGeological Survey of IndiaGeneral information on diamond formation, global distribution, resources, genesis. Prospects in (India)Geological Survey of India ( book from India booth at PDAC), pp. 1-44IndiaDiamond genesis, general information
DS202003-0339
2020
Geological Survey of IndiaGeological Survey of IndiaMineral resources of India. ( first 19p. Kimberlites )Geological Survey of India, 75p. PdfIndiadiamond

Abstract: India has a rich tradition of mineral exploration. Innumerable old workings, mine dumps slag heaps, etc. are the tell tale signs of this glorious tradition. The flourishing diamond trade in the Deccan peninsula, mainly in the Golconda kingdom, had attracted world’s attention during historical time. Copper and gold were also used locally since the days of Indus Valley civilizations. East India Company started exploration for coal in the Eighteenth century with setting up of , the premier Earth science organisation and the second oldest survey of the country, in 1851 for the systematic geological survey and prospecting for coal. India was a notable producer of gold in the early part of twentieth century and major exporter of mica, sillimanite, kyanite, magnetite and chromite. Metallurgical industry started with the setting up of steel plants at Burnpur, Jamshedpur and copper smelter at Ghatsila. Second World War created great demand for various minerals and metals including those of strategic importance e.g., tungsten. Industrial policy, formulated after Independence, brought about a radical change in the mining and metallurgical industry. During the post-Independence period, GSI has embarked upon the exploration for minerals, particularly in favourable geological milieu spread over Dharwar, Bastar, Singhbhum and Aravalli cratons. The investigations carried out since 1960s provide us firsthand information of different mineral occurrences as well as their potential. Keeping in tune with the modern trends of mineral exploration, the GSI oriented its programmes through multidisciplinary surveys. From time to time it equipped itself with state-of-the-art laboratories to back up its various exploration programmes. The efforts have led to discovery of several mineral deposits in virgin areas in different parts of the country. A few other central and state government organisations were also involved in mineral exploration now and then, mostly in collaboration with foreign organisations. The liberalisation of India’s National Mineral Policy in 1993 paved the way for the entry of private entrepreneurs, including those from overseas for carrying out mineral exploration. The database developed by GSI has been found very useful for taking investment decisions by the Multi-National Companies.
DS2001-0370
2001
Geological Survey of India RecordsGeological Survey of India RecordsBrief one paragraph .. detailed search for kimberlite lamproite in parts of Andhari basinal area. Chandrapur district.India Geological Survey Records, No. 134, 1, p. 136.IndiaNews item - exploration
DS2001-0371
2001
Geological Survey of India RecordsGeological Survey of India RecordsBrief one paragraph... regional surveys in parts of Chandapur and Chandara districtsIndia Geological Survey Records, No. 134, 1, p. 136.IndiaNews item - exploration
DS2001-0372
2001
Geological Survey of India RecordsGeological Survey of India RecordsBrief one paragraph .. assessment of Diamondiferous nature of Anampalle kimberlite body.India Geological Survey Records, No. 134, 1, p. 308.IndiaNews item - exploration
DS2001-0373
2001
Geological Survey of India RecordsGeological Survey of India RecordsBrief one small paragraph... delineation and assessme tof kimberlites identified in Kayabdyrg area, Anantapur district.India Geological Survey Records, No. 134, 1, p. 308.IndiaNews item - exploration
DS2001-0374
2001
Geological Survey of India RecordsGeological Survey of India RecordsBrief paragraph .. regional surveys around Kambaduru Timmasamudram, Setturu and Rayanapalle in Anantapur district.India Geological Survey Records, No. 134, 1, p. 308.IndiaNews item - exploration
DS2001-0375
2001
Geological Survey of India RecordsGeological Survey of India RecordsBrief one paragraph - search for kimberlites in the granitic terrain of Gulbarga, raichur and Chitradurga districts.India Geological Survey Records, No. 135, 1, p. 287.IndiaNews item - exploration
DS1998-0496
1998
Geological Survey of NorwayGeological Survey of NorwayGeology of the eastern Finnmark - western Kola Peninsula regionNgu, Special Paper No. 7, ( approx. 295 NOK)Finland, Russia, Kola, FennoscandiaGeology - Archean, geochemistry, geochronology
DS1990-0558
1990
Geological Survey of South AfricaGeological Survey of South Africa, Annual Technical Report for 1989Schuller kimberliteGeological Survey of South Africa, Annual Technical Report for 1989, p. 106South AfricaBrief description of project, Schuller
DS1995-0624
1995
Geological Survey of South AfricaGeological Survey of South AfricaGeological map of the Limpopo mobile beltGeological Survey of South Africa, 1 map 1: 500, 000South AfricaMap -ad, Limpopo mobile belt
DS1988-0247
1988
Geological Survey of Western AustraliaGeological Survey of Western AustraliaDirector's report: Diamonds mentionedGeological Survey of Western Australia, pp. 8-10AustraliaNews item
DS201803-0448
2018
Geological Survey of Western AustraliaGeological Survey of Western AustraliaDiamond exploration and prospectivity of Western Australia.Geological Survey of Western Australia, digital data packageAustraliareview - exploration
DS201803-0449
2018
Geological Survey of Western AustraliaGeological Survey of Western AustraliaFrogtech Geoscience 2017, Canning Basin SEEBASE study and GIS dat a package.Geological Survey of Western Australia, Report 182, 297p.Australiadeposit - Ellendale area

Abstract: In 2005, Frogtech Geoscience completed OZ SEEBASE - a continental-scale depth-to-basement grid which shows the distribution of Phanerozoic basins across Australia. OZ SEEBASE is an open-file study that has been downloaded 1000s of times by industry, government and academia. This was followed in 2006 by the Proterozoic OZ SEEBASE interpretation including the main Proterozoic basins of Australia. The 2005 and 2006 OZ SEEBASE incorporated results from the Canning Basin Project completed by SRK Consulting for Shell during 1998-99.
DS1975-0282
1976
Geological Surveys Of GuyanaGeological Surveys Of GuyanaAnnual Report for 1976Geological Survey Guyana, pp. 22-23.GuyanaDiamond Production
DS1998-0497
1998
Geologie en MijnbouwGeologie en MijnbouwSchurmann Symposium on Early Archean. Extended abstractsGeologie en Mijnbouw, Vol. 76, No. 4, pp. 341-378.Australia, South Africa, ZimbabweArchean, Craton
DS1991-0563
1991
Geologische RundschauGeologische RundschauCrustal dynamics -pathway and recordsGeologische Rundschau, Vol. 80, No. 2, pp. 207-495GlobalCrust, Crustal dynamics
DS201603-0378
2016
Geology InGeology InThe largest Tsavorite in the world. 185 grams from Karo area.Gemshare, 1p.Africa, TanzaniaGemstone - Tsavorite
DS1860-0306
1879
Geology MagazineGeology MagazineFossils from the Diamond Fields, South Africa KimberleyGeology Magazine , Dec. 2, Vol. 6, P. 192.Africa, South AfricaGeology, Palaeontology
DS1860-0400
1883
Geology MagazineGeology MagazineDiamond Mining at Kimberley, South AfricaGeology Magazine, Dec. 2, Vol. 10, PP. 460-461.South Africa, Griqualand West, Kimberley MineMining engineering, Production, Costs
DS201412-0279
2014
Geology pageGeology pageEarth's mantle plasticity explained. ( precis of Nature article)geologypage.com, 1p. AbstractMantleConvection
DS201412-0280
2014
Geology pageGeology pageIron in Earth's core weakens before melting.(precis of Science article)geologypage.com, 1p. AbstractMantleMelting
DS1986-0283
1986
Geology TodayGeology TodayThe mysteries of the diamondGeology Today, Nov-Dec. pp. 166-167GlobalDiamond, History
DS1986-0284
1986
Geology TodayGeology TodayGeodigest: the mysteries of the diamondGeology Today, Vol. 2, No. 6, November-December pp. 166-167GlobalPopular overview
DS1991-0564
1991
Geology TodayGeology TodayBuried circular structure found beneath Lake HuronGeology Today, Vol. 7, No. 2, March-April p. 42OntarioGeophysics -magnetics, Tectonics -circular
DS202012-2216
2020
GeologypageGeologypageNatural nanodiamonds in oceanic rocks.Geologypage.com, http://www.geologypage .com/2020/10/natural- nanodiamonds-in- oceanic-rocks.html Globalnanodiamonds

Abstract: Natural diamonds can form through low pressure and temperature geological processes on Earth, as stated in an article published in the journal Geochemical Perspectives Letters. The newfound mechanism, far from the classic view on the formation of diamonds under ultra-high pressure, is confirmed in the study, which draws on the participation of experts from the Mineral Resources Research Group of the Faculty of Earth Sciences of the University of Barcelona (UB).
DS1989-0751
1989
Geoltrain, S.Kaufman, A.A., Geoltrain, S., Knoshaug, R.N.Influence of induced polarization in inductive methodsGeoexploration, Vol. 26, No. 2, November pp. 75-94GlobalGeophysics, IP methodology
DS201611-2110
2016
Geomann, K.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).
DS1981-0335
1981
Geopeko ltd, DESIGN AND CONSTRUCTION P.Perring, R., Turley, S., Geopeko ltd, DESIGN AND CONSTRUCTION P.El 2411, El 2412, El 2417, El 2418, El 2419, El 2420, El 242Northern Territory Open File., No. CR 82-124, UNPUBL.Australia, Northern TerritoryGeochemistry, Prospecting, Stream Sediment Sampling, Assay
DS1982-0478
1982
Geopeko ltd.O'connor, D., Geopeko ltd.El 3146 Final Report 19/10/81 to 17/6/82Northern Territory Open File., No. CR 82-272, 10P. 1 MAP UNPUBL.Australia, Northern TerritoryDiamonds, Geochemistry, Geophysics, Stream Sediment Sampling
DS1982-0332
1982
Geopeko ltd., DESIGN AND CONSTRUCTION PTY.Kirkpatrick, B.L. , Geopeko ltd., DESIGN AND CONSTRUCTION PTY.El 2411- Annual Report for the Period of 3 December 1980 To2 December 1981.Northern Territory Open File., No. CR 81-121, 7P. UNPUBL.Australia, Northern TerritoryRegional Geology, Drilling, Stream Sediment Sampling, Geochemis
DS1982-0333
1982
Geopeko ltd., DESIGN AND CONSTRUCTION PTY.Kirkpatrick, B.L., Geopeko ltd., DESIGN AND CONSTRUCTION PTY.El 2412- Final Report for the Period 3 December 1980 to 2 December 1981.Northern Territory Open File., No. CR 82-120 (A, B), 7P. UNPUBL.Australia, Northern TerritoryGeochemistry, Drilling, Alluvials, Fitzmaurice Mobile Zone, Vict
DS1982-0334
1982
Geopeko ltd., DESIGN AND CONSTRUCTION PTY.Kirkpatrick, B.L., Geopeko ltd., DESIGN AND CONSTRUCTION PTY.El 2504 Annual Report for Period December 3, 1980 to December 2, 1981.Northern Territory Open File., No. CR 82-114, 7P. UNPUBL.Australia, Northern TerritoryRegional Geology, Alluvials, Geochemistry, Gravels
DS1982-0335
1982
Geopeko ltd., DESIGN AND CONSTRUCTION PTY.Kirkpatrick, B.L., Geopeko ltd., DESIGN AND CONSTRUCTION PTY.El 2411, El 2504 and El 2513- Bonaparte Gulf Basin, Nt ReporNorthern Territory Open File., No. CR 82-122, 7P. 34 LOGS UNPUBL.Australia, Northern TerritoryRegional Geology, Drilling, Logging, Alluvials, Legune Platform
DS1982-0493
1982
Geopeko ltd., DESIGN AND CONSTUCTION P.Perring, R., Turley, S., Geopeko ltd., DESIGN AND CONSTUCTION P.El 2417, El 2418, El 2419, El 2420, El 2421, El 2513, El 251Northern Territory Open File., No. CR 82-119, 12P. UNPUBL.Australia, Northern TerritoryGeophysics, Geochemistry, Prospecting, Stream Sediment Sampling
DS1982-0519
1982
Geopeko ltd., PEKO WALLSEND OPERATIONS LTD.Ricketts, C., Geopeko ltd., PEKO WALLSEND OPERATIONS LTD.El 3010 Daly River Northern Territory Final Report 27/10/81to 23/9/82.Northern Territory Geological Survey, No. CR 82/350, 5P.Australia, Northern TerritoryProspecting, Geochemistry
DS1982-0520
1982
Geopeko ltd., WALLSEND OPERATIONS LTD.Ricketts, C., Geopeko ltd., WALLSEND OPERATIONS LTD.El 3011 Daly River Northern Territory Final Report 27/10/81to 23/9/82.Northern Territory Geological Survey, No. CR 82/351, 6P.Australia, Northern TerritoryProspecting, Geochemistry
DS1993-0532
1993
Geophysical Data CentreGeophysical Data CentreAeromagnetic and bouguer gravity maps -colour plots 1:1, 000, 000 shaded relief total magnetic and bouguer gravityGeophysical Data Centre, $ 50.00 per plotManitoba, SaskatchewanGeophysics -magnetics, Gravity maps
DS1995-0625
1995
Geophysical Data CentreGeophysical Data CentreMagnetic and gravity maps of CanadaNrcan.geological Society Of Canada (gsc)., 1: 7, 500, 000 approx. $ 50.00 eachCanadaGeophysics -maps
DS1996-0515
1996
Geophysical Data CentreGeophysical Data CentreAbitibi Subprovince, aeromagnetic and Bouguer gravity mapsGeological Survey of Canada Geophysical Data Centre, 1:500, 000 cost $ 50.00 PER PLOT.QuebecGeophysics -aeromagnetics, bouguer gravity, Abitibi Subprovince
DS1994-0610
1994
Geophysical Lab ManualGeophysical Lab ManualGeophysical Lab ManualEcoTech Research, $ 24.00GlobalComputer, Program -manual
DS202103-0380
2021
Geophysics ContractorsGeophysics ContractorsCompiled List of geophysical contractors sent out to members of SEGMIN. *** not specific to diamonds Geophysical contractors, SEGMIN website 13p. PdfGlobalgeophysics
DS1988-0248
1988
Geophysics: the Leading Edge of ExplorationGeophysics: the Leading Edge of ExplorationAn overview of the geophysical activities in ChinaGeophysics: the Leading Edge of Exploration, Vol. 7, No.3, March pp. 23-25ChinaBlank
DS201601-0017
2015
Georg, R.B.Georg, R.B., Shahar, A.The accretion and differentiation of Earth under oxidizing conditions.American Mineralogist, Vol. 100, pp. 2739-2748.MantleCore, formation

Abstract: We present a new approach to model planetary accretion and continuous core formation, and discuss the implications if Earth accreted under conditions initially more oxidized than the modern day mantle. The modified model uses the same partitioning data that were previously used to model accretion under reducing conditions, however, changing the partitioning between accreting metal and silicate mantle means that reducing conditions fail to meet expected core/mantle values. Instead, the model requires conditions more oxidized than the modern day mantle to converge and to yield expected elemental core/mantle distribution values for moderately siderophile elements. The initial oxygen fugacity required to provide the crucial level of oxidation is approximately ?IW ~ ?1.2 to ?1.7 and thus is in the range of carbonaceous and ordinary chondrites. The range of peak pressures for metal silicate partitioning is 60-6 GPa and oxygen fugacity must decrease to meet modern FeO mantle contents as accretion continues. Core formation under oxidizing conditions bears some interesting consequences for the terrestrial Si budget. Although the presented partitioning model can produce a Si content in the core of 5.2 wt%, oxidizing accretion may limit this to a maximum of ~3.0 to 2.2 wt%, depending on the initial fO2 in BSE, which places bulk earth Mg/Si ratio between 0.98-1.0. In addition, under oxidizing conditions, Si starts partitioning late during accretion, e.g., when model earth reached >60% of total mass. As a consequence, the high P-T regime reduces the accompanied isotope fractionation considerably, to 0.07‰ for 5.2 wt% Si in the core. The isotope fractionation is considerably less, when a maximum of 3.0 wt% in the core is applied. Under oxidizing conditions it becomes difficult to ascertain that the Si isotope composition of BSE is due to core-formation only. Bulk Earth’s Si isotope composition is then not chondritic and may have been inherited from Earth’s precursor material.
DS1970-0082
1970
GeorgeGeorge, Ward, VivienneDiamonds of CherokeeTreasure World, Publishing P.o. Drawer L, Conroe Texas, 60P.United States, California, West CoastKimberley, History
DS200812-0040
2008
George, A.K.Arafin, S., Singh, R.N., George, A.K., Al Lazki, A.Thermoelastic and thermodynamic properties of harzburgite - an upper mantle rock.Journal of Physics and Chemistry of Solids, Vol. 69, 7, pp. 1766-1774.MantleGeochemistry
DS201801-0016
2017
George, B.G.Gautam, I., Bhutani, R., Balakrishnan, S., Chatterjee, A., George, B.G., Ray, J.S.142Nd/144Nd of alkaline magmas in Phenai Mat a complex, Chhota Udaipur, Deccan flood basalt province.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 14.Indiaalkaline rocks

Abstract: The 65 million year old alkaline plug at Phenai Mata Complex, in Chota Udaipur sub province, is often linked to the last pulse of the Deccan volcanism. However, many believe that the Deccan-Reunion mantle plume that was responsible for the generation of flood basalts might not have been the source of Phenai Mata. It, however, could have acted as a heat source for these magmas derived from the subcontinentallithospheric- mantle (SCLM). Since the SCLM is generally considered to be a nonconvective mantle domain it has the potential to preserve some of the geochemical evidence of the early silicate Earth differentiation, e.g., 142Nd anomaly. In search of such signatures we analysed alkali basalts from the complex for their 142Nd/144Nd using high precision thermal ionization mass spectrometry. Whereas the geochemical characterization of these samples confirmed the lithospheric origin of their source magmas, their ? 142Nd compositions are found to be normal with respect to terrestrial standards. We infer that either the mantle source of Phenai Mata does not represent a true non-convective mantle or it is too young to retain any evidence of 146Sm decay.
DS200612-0445
2006
George, C.George, C., Kirkpatrick, C.Assessing national sustainable development stratgies: strengthening the links to operational policy.Natural Resources Forum, Vol. 30, 2, May pp. 146-156.GlobalEnvironment
DS1975-1032
1979
George, G.R.George, G.R.Leucite HillsWyoming Geol. Association Guidebook, Vol. 2, PP.216-217.United States, Wyoming, Rocky Mountains, Leucite HillsBlank
DS1950-0269
1956
George, H.K.Dixon, C.G., George, H.K.Bibliography of the Geology and Mining of British GuianaGeological Survey British Guiana, Bulletin. 52, 86p.GlobalBibliography
DS1960-0791
1967
George, P.T.Bennett, G., Brown, D.D., George, P.T., Leahy, E.J.Operation KapuskasingOntario Department of Mines M.P., No. 10, 72P.Canada, Ontario, James Bay LowlandsTectonics, Rift Structure, Geomorphology
DS1960-0801
1967
George, P.T.Brown, D.D., Bennett, G.S., George, P.T.The Source of Alluvial Kimberlite Indicator Minerals in The james Bay Lowland.Ontario Department of Mines miscellaneous Publishing, No. 7, 35P.Canada, OntarioHistory, Prospecting, Geochemistry
DS2002-0553
2002
George, R.M.George, R.M., Rogers, N.W.Plume dynamics beneath the African plate inferred from the geochemistryContribution to Mineralogy and Petrology, Vol. 143, 5, pp.Mantle, AfricaTectonics, hotspots
DS201412-0281
2014
George, T.George, T.Karowe mine A diamond development success story.SRK and Friends Diamond Short Course, March 1, ppt p. 209-218.Africa, BotswanaHistory - development
DS201412-0282
2014
George, T.George, T., Armstrong, J.Karowe mine - a diamond development success story.Vancouver Kimberlite Cluster, Jan. 24, 1p. AbstractAfrica, BotswanaHistory - Karowe
DS2001-1245
2001
Georghious, P.E.Wilton, D.H.C., Taylor, D.H.C., Georghious, P.E.Kimberlites in northern Labrador and NunavutNorth Atlantic Minerals Symposium held May 27-30, pp. 191. abstract.Quebec, Labrador, Ungava, Nunavut, Northwest TerritoriesCape Kakkiviuak, Killiniq Island
DS201602-0230
2016
Georgiev, N.Petrik, I., Janak, M., Froitzheim, N., Georgiev, N., Yoshida, K., Sasinkova, V., Konecny, P., Milovska, S.Triassic to Early Jurassic (c.200 Ma) UHP metamorphism in the Central Rhodopes: evidence from U-Pb-Th dating of monazite in diamond bearing gneiss from Chelelpare, Bulgaria.Journal of Metamorphic Geology, in press available, 44p.Europe, BulgariaGneiss - diamonds

Abstract: Evidence for ultrahigh-pressure metamorphism (UHPM) in the Rhodope Metamorphic Complex comes from occurrence of diamond in pelitic gneisses, variably overprinted by granulite facies metamorphism, known from several areas of the Rhodopes. However, tectonic setting and timing of UHPM are not interpreted unanimously. Linking age to metamorphic stage is a prerequisite for reconstruction of these processes. Here we use monazite in diamond-bearing gneiss from Chepelare (Bulgaria) to date the diamond-forming UHPM event in the Central Rhodopes. The diamond-bearing gneiss comes from a strongly deformed, lithologically heterogeneous zone (Chepelare Mélange) sandwiched between two migmatized orthogneiss units, known as Arda-I and Arda-II. Diamond, identified by Raman micro-spectroscopy, shows the characteristic band mostly centred between 1332 and 1330 cm?1. The microdiamond occurs as single grains or polyphase diamond + carbonate inclusions, rarely with CO2. Thermodynamic modelling shows that garnet was stable at UHP conditions of 3.5-4.6 GPa and 700-800 °C, in the stability field of diamond, and was re-equilibrated at granulite facies/partial melting conditions of 0.8-1.2 GPa and 750-800 °C. The texture of monazite shows older central parts and extensive younger domains which formed due to metasomatic replacement in solid residue and/or overgrowth in melt domains. The monazite core compositions, with distinctly lower Y, Th and U contents, suggest its formation in equilibrium with garnet. The U-Th-Pb dating of monazite using electron microprobe analysis yielded a c. 200 Ma age for the older cores with low Th, Y, U and high La/Nd ratio, and a c. 160 Ma age for the dominant younger monazite enriched in Th, Y, U and HREE. The older age of around 200 Ma is interpreted as the timing of UHPM whereas the younger age of around 160 Ma as granulite facies/partial melting overprint. Our results suggest that UHPM occurred in Late Triassic to Early Jurassic time, in the framework of collision and subduction of continental crust after the closure of Palaeotethys.
DS201604-0621
2016
Georgiev, N.Petrik, I., Janak, M., Froitzheim, N., Georgiev, N., Yoshida, K., Sasinkova, V., Konecny, P., Milovska, S.Triassic to Early Jurassic ( c. 200Ma) UHP metamorphism in the Central Rhodopes: evidence from U-Pb dating of monazite in diamond bearing gneiss from Chepelare ( Bulgaria).Journal of Metamorphic Geology, Vol. 34, 3, pp. 265-291.Europe, BulgariaUHP diamond bearing gneiss
DS201606-1105
2016
Georgiev, N.Petrik, I., Janak, M., Froitzheim, N., Georgiev, N., Yoshida, K., Sasinkova, V., Konecny, P., Milovska, S.Triassic to Early Jurassic ( c. 200Ma) UHP metamorphism in the central Rhodopes: evidence from U-Pb-Th dating of monazite in diamond bearing gneiss from Chepelare Bulgaria.Journal of Metamorphic Geology, Vol. 34, 3, pp. 265-291.Europe, BulgariaDiamonds in gneiss
DS201012-0643
2010
Georgieva, M.Ruskov, T., Spirov, I., Georgieva, M., Yamamoto, S., Green, H.W., McCammon, C.A., Dobrzhinetskaya, L.F.Mossbauer spectroscopy studies of the valence state of iron in chromite from the Luobusa Massif of Tibet: implications for a highly reduced mantle.Journal of Metamorphic Geology, Vol. 28, 5, pp. 551-560.Asia, TibetMetasomatism
DS1992-1759
1992
GeorgiyevskayaZyablitsev, A.Yu., Rozanov, K.I., Matrosova, T.I., GeorgiyevskayaDavidite-chevkinite association from the Central Baikal RegionDoklady Academy of Sciences USSR, Earth Science Section, Vol. 314, No. 1-6, September pp. 201-205.RussiaMineralogy, Geochemistry
DS1990-0559
1990
GeoscanGeoscanBibliography of information listed -term diatremes,diamonds, Kimberlites in GEOSCAN North of 60Geoscan database, 51 referencesNorthwest Territories, YukonBibliography, Assessment/Federal inforM.
DS1990-0560
1990
Geoscience CanadaGeoscience CanadaThe eastern Churchill Province, Torngat and New Quebec orogens: an overview and papers from a Geological Association of Canada (GAC) session meetingGeoscience Canada, Vol. 17, No. 4, December pp. 217-320pQuebec, Labrador, UngavaBook -table of contents, Orogens -Torngat and New Quebec
DS1996-0516
1996
Geoscience CanadaGeoscience CanadaNunavut - arctic climatesGeoscience Canada, Vol. 23, No. 4, Dec. pp. 177-270Arctic, Canada, Northwest TerritoriesClimate, Permafrost
DS200412-0652
2004
Geosociety.orgGeosociety.orgEarth Scientist's Periodic Table of the Elements and their ions. Designed to con-textualize trends in natural scienceGeosociety.org, Chart, TableTechnologyGeochemistry
DS1993-0533
1993
GeoteM.GeoteM.Point Lake (discovery pipe) and Willy-Nilly kimberliteGeotem Brochure, 1pNorthwest TerritoriesGeophysics, GeoteM.
DS1982-0220
1982
GeoterrexGeoterrexAnalog Records from an Airborne Electromagnetic and Magnetic Survey of Parts of the Upper Peninsula of Michigan. (wisconsin).United States Geological Survey (USGS) OPEN FILE., No. 82-0060 A, B, AND No. 83-195A, B.United States, Michigan, Wisconsin, Great LakesMid-continent
DS1993-0534
1993
GeoterrexGeoterrexExploration for kimberlites: a review of geophysical exploration methodswith examples from Point Lake, northwest Territories using an optimized GEOTEM.Geoterrex Handout PDA Conference March 30, 1993, 23pNorthwest TerritoriesGeophysics, GEOTEM.
DS1986-0285
1986
GeotimesGeotimesDana misplaced diamonds... Sierra Nevada CaliforniaGeotimes, Vol. 31, No. 12, December p. 20CaliforniaNews item
DS1986-0286
1986
GeotimesGeotimesWyoming diamonds stole the mineral show in FebruaryGeotimes, Vol. 31, No. 4, April p. 25WyomingProduction since 1975 126 diamonds 15.38 carats on stat
DS1990-0561
1990
GeotimesGeotimesCarbon-sink paradox stimulates scientific discussion of greenhouse.-global carbon cycleGeotimes, Vol. 35, No. 5, May p. 7GlobalGlobal carbon cycle, Greenhouse
DS1990-0562
1990
GeotimesGeotimesZoning of magmas in volcanic eruptionsGeotimes, Vol. 35, No. 5, May p. 9GlobalMagma, Dual liquid flow
DS1992-0558
1992
GeotimesGeotimesIndustrial minerals overview: very brief mention of diamond activity around the worldGeotimes, Vol. 37, No. 2, February p. 17China, Canada, Saskatchewan, AustraliaNews item, Diamond exploration
DS1994-0611
1994
GeotimesGeotimesYoung diamond reveals gem's timeless qualityGeotimes, Vol. 39, No. 10, Oct. p. 5.Democratic Republic of CongoNews item, Precis of J. Geology article
DS1995-0626
1995
GeotimesGeotimesEVS environmental visualization systemUnknown, GlobalComputer, Program -EVS environment
DS1995-0627
1995
GeotimesGeotimesLower mantle may harbor hydrogenGeotimes, Vol. 40, No. 2, Feb. p. 8.MantlePerovskite
DS1996-0517
1996
GeotimesGeotimesBrief review of paper on high speed computing and seismology... core mantleboundary...Geotimes, Vol. 41, No. 10, Oct. pp. 10-12.MantleGeophysics -seismic, Core-mantle boundary
DS1996-0518
1996
GeotimesGeotimesNew theories on continental driftGeotimes, Feb. pp. 6-7MantleTectonics, Continental drift
DS1996-0519
1996
GeotimesGeotimesDiamonds: Wyoming's best friendGeotimes, Feb. pp. 9-10.WyomingNews item, Diamond exploration
DS1998-0498
1998
GeotimesGeotimesGeobase map mapping system and display toolsGeotimes, GlobalComputer, Program - GeoBasemap
DS1998-0499
1998
GeotimesGeotimesProspect Explorer... software product - multicomponent dataGeotimes, GlobalComputer, Program - Prospect Explorer
DS1998-0500
1998
GeotimesGeotimesTerraSoar.. geospatial imageryGeotimes, GlobalComputer, Program - TerraSoar
DS1998-0501
1998
GeotimesGeotimesHot spots and low velocitiesGeotimes, Vol. 43, No. 10, Oct. pp. 11, 2.MantleHot spots
DS1998-0502
1998
GeotimesGeotimesMagnetic anomaly dat a for the former Soviet UnionGeotimes, RussiaComputer, Geophysics - magnetics
DS1999-0248
1999
GeotimesGeotimesSiberian slab buried, not lostGeotimes, Vol. 44, No. 4, Apr. p. 9.Russia, SiberiaSubduction, Slab - brief account of Van der Voo's Lake Baikal
DS2000-0332
2000
GeotimesGeotimesEarth's interior - raising hot spots..Geotimes, November p. 10. (1p).GlobalHot spots - assumptions - brief overview.
DS2000-0333
2000
GeotimesGeotimesSeismology gives more history to cratonic rocks. Brief outline Kaapvaal project and web www.ciw.edu/kaapvaalGeotimes, March p. 8.MantleCraton - Kaapvaal, Geophysics - seismics
DS2001-0376
2001
GeotimesGeotimesRefining the core-mantle boundaryGeotimes, Jan. p. 7. (1p)MantleModel - onion layer
DS1986-0348
1986
Gephart, J.Hauser, E.C., Barnes, A., Gephart, J., Latham, T., Lundy, J.Brown.COCORP deep reflection transect in Arizona: across the transition zone from Colorado Plateau to core complexesEos, Vol. 67, No. 44, Nov. 4th. p. 1096. (abstract.)Colorado Plateau, ArizonaGeophysics, Tectonics
DS1994-0612
1994
Gephart, J.W.Gephart, J.W.Topography and subduction geometry in the central Andes: clues to the mechanics of noncollisional orogenJournal of Geophy. Res, Vol. 99, B6, June 10, pp. 12, 279-288AndesTectonics, Orogeny
DS202008-1396
2020
GerGonzales-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.
DS201212-0143
2012
Gera, N.L.Das, J.N., Korkoppa, M.M., Fareeduddin, Shivana, S., Srivastava, J.K., Gera, N.L.Tuffisitic kimberlite from eastern Dharwar craton, Undraldoddi area, Raichur District, Karnataka, India10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractIndia, KarnatakaDeposit - Undraldoddi area
DS201412-0165
2013
Gera, N.L.Das, J.N., Korakoppa, M.M., Fareeduddin, Shivana, S., Srivastava, J.K., Gera, N.L.Tuffisitic kimberlite from eastern Dharwar craton, Undraldoddi area, Raichur district, Karnataka India.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 109-128.India, KarnatakaDeposit - Raichur district
DS1980-0188
1980
Geraci, P.Keller, G.R., Russell, D.R., Hinze, W.J., Reed, J.E., Geraci, P.Bouguer Gravity Anomaly Map of East Central Midcontinent Of the United States.National Technical Information Service NUREG CR/1663, 12P.GlobalMid-continent
DS1975-1097
1979
Geraci, P.C.Keller, E.G., Russel, D.R., Hinze, W.J., Reed, J.E., Geraci, P.C.A Bouguer Gravity Map of a Portion of the Central Midcontinent.Eos, Vol. 61, No. 5, P. 48.GlobalMid-continent
DS2000-0334
2000
Geraldes, M.C.Geraldes, M.C., Van Schmus, W.R., Teixeria, W.Three parallel crystal accretionary arcs (1.79-1.3 Ga) in the southwest Amazon Craton, State of Mato Grosso Brasil.Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Mato GrossoGeochronology, Craton - alkaline magmatism
DS200612-1432
2006
Geraldes, M.C.Tohver, E., Teixeira, W., Van der Pluijum, B., Geraldes, M.C., Bettencourt, J.S., Rizzotto, G.Restored transect across the exhumed Grenville Orogen of Laurentia and Amazonia, with implications for crustal architecture.Geology, Vol. 34, 8, pp. 669-672.South America, BrazilGeochronology, Amazon Craton, tectonics
DS200512-0031
2002
GerasimAshchepkov, I.V., Saprykin, A.I., Gerasim, Khmeintkova, Cheremenykk, Safonova, Rasskazov, Kinolin, VladykinPetrochemistry of mantle xenoliths from Sovgavan Plateau, Far East Russia.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 213-222.RussiaXenoliths
DS201012-0247
2010
GerasimchukGrakhanov, S.A., Malanin, Yu.A., Pavlov, Afanasev, Pokhilenko, Gerasimchuk, LipashovaRhaetian diamond placers in Siberia.Russian Geology and Geophysics, Vol. 51, pp. 127-135.Russia, Yakutia, SakhaAlluvials
DS201112-0005
2011
GerasimchukAfanasev, 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
DS1988-0249
1988
Gerasimchuk, A.V.Gerasimchuk, A.V., Serenko, V.P.Physical substance prerequisites for the zonation Of the basement of Daldyno-Alakit region according to geophysical data.(Russian)Geologii i Geofiziki, (Russian), No. 11, pp. 74-80RussiaMineralogy, Daldyno-Alakit
DS201012-0405
2010
Gerasimchuk, A.V.Kornilova, V.P., Spetsius, Z.V., Lelukh, M.I., Gerasimchuk, A.V.Pecularities of garnets from kimberlites of Nakynsky field, Yakutia.International Mineralogical Association meeting August Budapest, abstract p. 571.Russia, YakutiaChemistry - Mayaskaya, Nuyrbinskaya pipes
DS201112-0950
2011
GerasimenkoShestakov, N.V., Gerasimenko, Takalhashi, Tasahara, Bormotov, Bykov,Kolomiets et al.Present tectonics of the southeast of Russia as seen from GPS observations.Geophysical Journal International, Vol. 184, 2, pp. 529-540.RussiaGeodynamics
DS1998-1215
1998
GerasimovRass, I.T., Gerasimov, Laputina, IllupinDiamond occurrence in kimberlites dependent on melting depths and rates of cooling of parental mantle magmas.7th. Kimberlite Conference abstract, pp. 723-4.South Africa, Siberia, RussiaMagmatism, Deposit - Wesselton, Mir
DS2001-0055
2001
GerasimovAshchepkov, I.V. , Vladykin, Gerasimov, Saprykin, et al.Temperature gradient and structure of the lithospheric block beneath the southeastern margin of Siberia cratonDoklady Academy of Sciences, Vol. 378, No. 4, May-June pp. 530-35.Russia, Siberia, Aldan shieldXenolith evidence from kimberlites, Geothermometry
DS2001-0056
2001
GerasimovAshchepkov, I.V., Gerasimov, Saprykin, Vladykin, AnoshinTrace element composition of deep seated mineral inclusions from Aldan lamproites: first la ICP MS studyGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.5, abstract.RussiaLamproites, Amga River basin
DS2001-0058
2001
GerasimovAshchepkov, L.V., Vladykin, Gerasimov, SaprykinPetrology and mineralogy of disintegrated mantle inclusions of kimberlite like diatremes from Aldan areaAlkaline Magmatism -problems mantle source, pp. 161-76.Russia, Aldan shieldMantle reconstructions - Chompolo field
DS2001-0916
2001
GerasimovPhilippot, P., Blichertoft, Perchuk, Costa, GerasimovLutetium(Lu)- Hafnium(Hf) and Argon- Argon chronology supports extreme rate of subduction zone metamorphism deduced geospeedometryTectonophysics, Vol. 342, No. 2, pp. 23-38.MantleGeochronology, Argon, Lutetium, Hafnium, Subduction
DS1984-0298
1984
Gerasimov, A.YU.Gerasimov, A.YU., Povaremnykh, A.S., Matsyuk, S.S., Kharkiv, A.Hardness of Chromium Containing Garnets from KimberlitesMineral. Zhur., Vol. 6, No. 2, PP. 42-50.RussiaMineralogy
DS1984-0299
1984
Gerasimov, A.YU.Gerasimov, A.YU., Povarennykh, S.S., Matsyuk, S.S., Kharkiv, A.The Hardness of Chromium Bearing Garnets from KimberlitesMineral. Zhurn., Vol. 6, No. 2, PP. 42-50.RussiaBlank
DS1986-0003
1986
Gerasimov, A.Yu.Afanasyev, V.P., Gerasimov, A.Yu., Babenko, V.V.Self-limitation of picroilmenite during reduction processes as a resultof anistropy of the mechanicalproperties.(Russian)In: Mineralogical crystallography and its application to mineral, pp. 159-163RussiaMineralogy, Picroilmenite
DS201507-0320
2015
Gerasimov, E.Yu.Lazereva, E.V., Zhmodik, S.M., Dobretsov, N.L., Tolstov, A.V., Shcherbov, B.L., Karmanov, N.S., Gerasimov, E.Yu., Bryanskaya, A.V.Main minerals of abnormally high grade ores of the Tomtor deposit ( Arctic Siberia).Russian Geology and Geophysics, Vol. 56, pp. 844-873.RussiaDeposit - Tomtor
DS1989-1263
1989
Gerasimov, M.V.Rekharskiy, V.I., Dikov, Yu.P., Mukhin, L.M., Gerasimov, M.V.Geostages and endogenic ore materialInternational Geology Review, Vol. 30, No. 11, Nov. pp. 1151-1161. Database # 17981RussiaMantle-crust relationship, Metallogeny
DS2001-0377
2001
Gerasimov, P.A.Gerasimov, P.A., Saprykin, A.I., Ashchepkov, AnoshinDetermination of rare earth elements (REE) in different minerals from mantle xenoliths by la ICPMS.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.50-1, abstract.MantleXenoliths
DS200512-0037
2001
Gerasimov, P.A.Ashchepkov,I.V., Vladykin, N.V., Gerasimov, P.A., Saprykin, A.I., Khmelnikova, O.S., Anoshin, G.N.Petrology and mineralogy of disintegrated mantle inclusions of kimberlite like diatremes from the Aldan Shield ( Chompolo field): mantle reconstructions.Alkaline Magmatism and the problems of mantle sources, pp. 161-176.RussiaDiatreme
DS1975-1033
1979
Gerasimovsky, V.I.Gerasimovsky, V.I.Geochemistry of Effusive Rocks of Rift ZonesPhysics and Chemistry of the Earth., Vol. 11, PP. 361-366.East AfricaLeucitite, Leucite
DS1981-0179
1981
Geraskina, O.YU.Geraskina, O.YU., Zxhikhareva, V.P., et al.Catalytic Oxidation Velocity of Crystals of Natural Diamond of Diverse Habits and in the Presence of Water Vapor.Mineral. Sbornik L'vov, Vol. 35, No. 2, PP. 52-56.RussiaCrystallogrphy
DS201703-0398
2017
Gerault, M.Coltice, N., Gerault, M., Ulvrova, M.A mantle convection perspective on global tectonics. ReviewEarth Science Reviews, Vol. 165, pp. 120-150.MantleTectonics

Abstract: The concept of interplay between mantle convection and tectonics goes back to about a century ago, with the proposal that convection currents in the Earth’s mantle drive continental drift and deformation (Holmes, 1931). Since this time, plate tectonics theory has established itself as the fundamental framework to study surface deformation, with the remarkable ability to encompass geological and geophysical observations. Mantle convection modeling has progressed to the point that connections with plate tectonics can be made, pushing the idea that tectonics is a surface expression of the global dynamics of one single system: the mantle-lithosphere system. Here, we present our perspective, as modelers, on the dynamics behind global tectonics with a focus on the importance of self-organisation. We first present an overview of the links between mantle convection and tectonics at the present-day, examining observations such as kinematics, stress and deformation. Despite the numerous achievements of geodynamic studies, this section sheds light on the lack of self-organisation of the models used, which precludes investigations on feedbacks and evolution of the mantle-lithosphere system. Therefore, we review the modeling strategies, often focused on rheology, that aim at taking into account self-organisation. The fundamental objective is that plate-like behaviour emerges self-consistently in convection models. We then proceed with the presentation of studies of continental drift, seafloor spreading and plate tectonics in convection models allowing for feedbacks between surface tectonics and mantle dynamics. We discuss the approximation of the rheology of the lithosphere used in these models (pseudo-plastic rheology), for which empirical parameters differ from those obtained in experiments. In this section, we analyse in detail a state-of-the-art 3D spherical convection calculation, which exhibits fundamental tectonic features (continental drift, one-sided subduction, trench and ridge evolution, transform shear zones, small-scale convection, and plume tectonics). This example leads to a discussion where we try to answer the question: can mantle convection models transcend the limitations of plate tectonics theory?
DS201711-2508
2017
Gerault, M.Coltice, N., Gerault, M., Ulvrova, M.A mantle convection perspective on global tectonics.Earth Science Reviews, Vol. 165, pp. 120-150.Mantletectonics

Abstract: The concept of interplay between mantle convection and tectonics goes back to about a century ago, with the proposal that convection currents in the Earth's mantle drive continental drift and deformation (Holmes, 1931). Since this time, plate tectonic theory has established itself as the fundamental framework to study surface deformation, with the remarkable ability to encompass geological and geophysical observations. Mantle convection modeling has progressed to the point where connections with plate tectonics can be made, pushing the idea that tectonics is a surface expression of the global dynamics of one single system: the mantle-lithosphere system. Here, we present our perspective, as modelers, on the dynamics behind global tectonics with a focus on the importance of self-organisation. We first present an overview of the links between mantle convection and tectonics at the present-day, examining observations such as kinematics, stress and deformation. Despite the numerous achievements of geodynamic studies, this section sheds light on the lack of self-organisation of the models used, which precludes investigations of the feedbacks and evolution of the mantle-lithosphere system. Therefore, we review the modeling strategies, often focused on rheology, that aim at taking into account self-organisation. The fundamental objective is that plate-like behaviour emerges self-consistently in convection models. We then proceed with the presentation of studies of continental drift, seafloor spreading and plate tectonics in convection models allowing for feedbacks between surface tectonics and mantle dynamics. We discuss the approximation of the rheology of the lithosphere used in these models (pseudo-plastic rheology), for which empirical parameters differ from those obtained in experiments. In this section, we analyse in detail a state-of-the-art 3-D spherical convection calculation, which exhibits fundamental tectonic features (continental drift, one-sided subduction, trench and ridge evolution, transform shear zones, small-scale convection, and plume tectonics). This example leads to a discussion where we try to answer the following question: can mantle convection models transcend the limitations of plate tectonic theory?
DS201804-0697
2018
Gerbasoni, F.Grutzner, T., Klemme, S., Rohrbach, A., Gerbasoni, F., Berndt, J.The effect of fluorine on the stability of wadsleyite: implications for the nature and depths of the transition zone in the Earth's mantle.Earth and Planteray Science Letters, Vol. 482, pp. 236-244.Mantletransition zone

Abstract: The Earth's mantle contains significant amounts of volatile elements, such as hydrogen (H), carbon (C) and the halogens fluorine (F), chlorine (Cl) and bromine (Br) and iodine (I). There is a wealth of knowledge about the global cycling of H and C, but there is only scant data on the concentrations of halogens in different Earth reservoirs and on the behavior of halogens during recycling in subduction zones. Here we focus on the storage potential of F in deeper parts of the Earth's mantle. The transition zone is a region in the Earth's mantle (410-660 km) known for its high water storage capacity, as the high pressure polymorphs of olivine, wadsleyite and ringwoodite are known to be able to incorporate several per-cent of water. In order to assess potential fractionation between water and F in the transition zone of the Earth's mantle, we set out to investigate the storage capacity of the halogen F in wadsleyite and olivine at transition zone conditions. Experiments were performed in a simplified mantle composition at temperatures from 1400?°C to 1900?°C and pressures from 17 up to 21 GPa in a multi anvil apparatus. The results show that F can shift the olivine-wadsleyite transition towards higher pressure. We find that F has an opposing effect to water, the latter of which extends the transition zone towards lower pressure. Moreover, the F storage capacity of wadsleyite is significantly lower than previously anticipated. F concentrations in wadsleyite range from to independent of temperature or pressure. The F storage capacity in wadsleyite is even lower than the F storage capacity of forsterite under transition zone conditions, and the latter can incorporate F under these conditions. Based on our data we find that the transition zone cannot be a reservoir for F as it is assumed to be for water. Furthermore, we argue that during subduction of a volatile-bearing slab, fractionation of water from F will occur, where water enters preferentially the transition zone and F remains in the peridotite of the lowermost upper mantle.
DS1999-0249
1999
Gerbault, M.Gerbault, M., Burov, E., Daignieres, M.Do faults trigger folding in the lithosphere?Geophysical Research Letters, Vol. 26, No. 2, Jan. 15, pp. 271-74.MantleTectonics, Lithosphere
DS201212-0241
2012
Gerbault, M.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
DS1960-0600
1965
Gerdeman, P.E.Snyder, F.G., Gerdeman, P.E.Explosive Igneous Activity Along an Illinois Missouri Kansas Axis.American Journal of Science, Vol. 263, PP. 465-493.Appalachia, United States, Illinois, Missouri, Kansas, Central StatesMid-continent, Structure, Tectonics
DS201312-0506
2013
GerdesKosler, J., Slama, Belousova, Corfu, Gehrels, Gerdes, Horstwood, Sircombe, Sylvester, Tiepolo, Whitehouse, WoodheadU-Pb detrital zircon analysis - results of an inter-laboratory comparison. (not specific to diamonds)Geostandards and Geoanalytical Research, Vol. 37, 3, pp. 243-259.GlobalZircon analyses
DS200412-1998
2004
Gerdes, A.Timmermann, H., Stedra, V., Gerdes, A., Noble, S.R., Parrish, R.R., Dorr, W.The problem of dating high pressure metamorphism: a U Pb isotope and geochemical study on eclogites and related rocks of the MarJournal of Petrology, Vol. 45, 7, pp. 1311-1338.Europe, Czech RepublicEclogite, UHP
DS200612-0827
2006
Gerdes, A.Liu, F.L., Gerdes, A., Liou, J.G., Xue, H.M., Liang, F.H.SHRIMP U Pb zircon dating from Sulu Dabie dolomitic marble, eastern China: constraints on prograde, ultrahigh pressure and retrograde metamorphic ages.Journal of Metamorphic Geology, Vol. 24, 7, Sept. pp. 569-589.ChinaGeochronology UHP
DS200712-0636
2007
Gerdes, A.Liu, F., Gerdes, A.Zoned zircon from eclogite leases in marbles from the Dabie-Sulu UHP belt: a clear record of ultra-deep subduction and fast exhumation.Plates, Plumes, and Paradigms, 1p. abstract p. A588.ChinaUHP
DS200712-1219
2007
Gerdes, A.Zeh, A., Gerdes, A., Klemd, R., Barton, J.M.Jr.Archean to Proterzooic crustal evolution in the Central Zone of the Limpopo belt ( South Africa - Botswana ): constraints from combined U Pb and Lu Hf isotope analyses of zircon.Journal of Petrology, Vol. 48, 8, pp.1605-1639.Africa, South Africa, BotswanaGeochronology
DS200712-1220
2007
Gerdes, A.Zeh, A., Gerdes, A., Klemd, R., Barton, J.M.Jr.Archean to Proterzooic crustal evolution in the Central Zone of the Limpopo belt ( South Africa - Botswana ): constraints from combined U Pb and Lu Hf isotope analyses of zircon.Journal of Petrology, Vol. 48, 8, pp.1605-1639.Africa, South Africa, BotswanaGeochronology
DS200812-0366
2008
Gerdes, A.Frei, D., Hutchinson, M.T., Gerdes, A., Heaman, L.M.Common lead corrected U Pb age dating of perovskite by laser ablation - magnetic sectorfield ICP-MS9IKC.com, 3p. extended abstractMantleGeochronology
DS200812-1307
2008
Gerdes, A.Zeh, A., Gerdes, A., Klemd, R., Barton, J.M.U Pb and Lu Hf isotope record of detrital zircon grains from the Limpopo Belt - evidence for crustal recycling at the Hadean to Early Archean transition.Geochimica et Cosmochimica Acta, Vol. 72, 21, Nov. 1, pp. 5304-5329.Africa, ZimbabweGeochronology
DS200912-0002
2009
Gerdes, A.Aeh, A., Gerdes, A., Barton, J.H.Archean accretion and crustal evolution of the Kalahari craton: the zircon age and Hf isotope record of granitic rocks- Barberton/Swaziland to Francistown Arc.Journal of Petrology, Vol. 50, 5, pp. 933-966.Africa, South AfricaGeochronology
DS200912-0244
2009
Gerdes, A.Gerdes, A., Kemp, A.L.S., Hancher, J.M., Schersten, A.Accessory minerals as tracers of crustal processes.Chemical Geology, Vol. 261, 3-4, April 30, pp. 197-198/MantleMineral chemistry
DS200912-0445
2009
Gerdes, A.Liu, F.L., Gerdes, A., Xue, H.M.Differential subduction and exhumation of crustal slices in the Sulu HP-UHP metamorphic terrane: insights from mineral inclusions, trace elements, U-Pb and Lu Hf isotope analyses of zircon in orthogneissJournal of Metamorphic Geology, Vol. 27, 9, pp. 805-825.ChinaUHP
DS201012-0459
2010
Gerdes, A.Luchs, T., Brey, G., Gerdes, A.Insights on the evolution of the lithospheric mantle underneath the Gibeon kimberlite field, Namibia.Goldschmidt 2010 abstracts, posterAfrica, NamibiaDeposit - Gibeon
DS201012-0532
2010
Gerdes, A.Nebel-Jacobsen, Y., Munker, C., Nebel, O., Gerdes, A., Metzger, K., Nelson, D.R.Reworking of Earth's first crust: constraints from Hf isotopes in Archean zircons from Mt. Narryer, Australia.Precambrian Rseaerch, in press available, 34p.AustraliaGeochronology
DS201012-0544
2010
Gerdes, A.Nuber, N., Gerdes, A., Brey, G., Grutter, H.Zircons from kimberlites at Lac de Gras, Canada - a section through the continental crust.International Mineralogical Association meeting August Budapest, abstract p. 561.Canada, Northwest TerritoriesDiamond morphology - size distribution
DS201112-0271
2011
Gerdes, A.Do Cabo, V., Sitnikova, M.A., Ellmies, R., Wall, F., Henjes-Kunst, F., Gerdes, A.Geological and geochemical characteristics of carbonatites of Lofdal, Namibia.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterAfrica, NamibiaCarbonatite
DS201112-0272
2011
Gerdes, A.Do Cabo, V., Sitnikova, M.A., Elmies, R., Wall, F., Henjes-Kunst, F., Gerdes, A.Geological and geochemical characteristics of carbonatites of Lofdal, NamibiaPeralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.140-143.Africa, NamibiaLofdal
DS201112-0273
2011
Gerdes, A.Do Cabo, V., Sitnikova, M.A., Elmies, R., Wall, F., Henjes-Kunst, F., Gerdes, A.Geological and geochemical characteristics of carbonatites of Lofdal, NamibiaPeralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.140-143.Africa, NamibiaLofdal
DS201112-0274
2011
Gerdes, A.Do Cabo, V.N., Wall, F., Sitnikova, M.A., Ellmies, R., Henjes-Kunst, F., Gerdes, A., Downes, H.Mid and heavy REE in carbonatites at Lofdal, Namibia.Goldschmidt Conference 2011, abstract p.770.Africa, NamibiaCarbonatite, dykes
DS201112-0364
2011
Gerdes, A.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H & E., Keller, J.In situ trace element and U Pb and Sr and Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.48-50.Europe, GermanyKaiserstuhl
DS201112-0365
2011
Gerdes, A.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H & E., Keller, J.In situ trace element and U Pb and Sr and Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.48-50.Europe, GermanyKaiserstuhl
DS201112-0366
2011
Gerdes, A.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H.E., Keller, J.In-situ trace element and U-Pb, Sr and Nd isotope analysis of accessory phases in Kaiserstuhl cabonatites.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GermanyCarbonatite
DS201112-0624
2011
Gerdes, A.Luchs, T., Brey, G., Gerdes, A.Chronological and thermal history of the lithospheric mantle underneath the Gibeon kimberlite field, Namibia.Goldschmidt Conference 2011, abstract p.1364.Africa, NamibiaRehoboth, Hanaus, Gibeon
DS201112-0679
2011
Gerdes, A.Millong, L.J., Gerdes, A., Groat, L.A.U-Pb geochronology and Lu-Hf isotope dat a from meta-carbonatites in the southern Canadian Cordillera.Goldschmidt Conference 2011, abstract p.1474.Canada, British ColumbiaCarbonatite
DS201112-0895
2011
Gerdes, A.Saalmann, K., Gerdes, A., Lahaye, Y., Hartmann, L.A., Remus, M.V.D., Laufer, A.Multiple accretion at the eastern margin of the Rio de la Plat a craton: the prolonged Brasiliano orogeny in southernmost Brazil.International Journal of Earth Sciences, Vol. 100, 2, pp. 355-378.South America, BrazilCraton, not specific to diamonds
DS201112-1157
2011
Gerdes, A.Zeh, A., Gerdes, A., Millonig, L.Hafnium isotope record of the Ancient Gneiss Complex, Swaziland, southern Africa: evidence for Archean crust-mantle formation and crust reworking between 3.66 and 2.73 Ga.Journal of the Geological Society, Vol. 168, pp. 953-964.Africa, SwazilandGeochronology
DS201212-0237
2012
Gerdes, A.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H.E., Keller, J.In situ trace element and U Pb and Sr Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.emc2012 @ uni-frankfurt.de, 1p. AbstractEurope, GermanyCarbonatite
DS201212-0238
2012
Gerdes, A.Ghobadi, M., Gerdes, A., Kogarko, L., Brey, G.New dat a on the composition and hafnium isotopes of zircons from carbonatites of the Khibiny Massif.Doklady Earth Sciences, Vol. 446, 1, pp. 1083-1085.RussiaCarbonatite
DS201212-0265
2012
Gerdes, A.Grutter, H.S., Gerdes, A., Marko, L., Heaman, L.M.U-Pb geochronology of perovskite and zircon from the Chigicherla kimberlites, Anatapur district, India.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractIndiaDeposit - Chigicherla
DS201212-0415
2012
Gerdes, A.Liu, F., Gerdes, A., Liu, P.U-Pb trace element and Lu-Hf properties of unique dissolution-repricipitation zircon from the UHP eclogite in the sw Sulu Terrane, eastern China.Gondwana Research, Vol. 22, 1, pp. 169-183.ChinaUHP
DS201212-0416
2012
Gerdes, A.Liu, F., Gerdes, A., Liu, P.U-Pb trace element and Lu-Hf properties of unique dissolution reprecipitation zircon from UHP eclogite in sw Sulu terrane, eastern China.Gondwana Research, Vol. 22, 1, July pp. 169-183.ChinaUHP
DS201212-0424
2012
Gerdes, A.Luchs, T., Brey, G.P., Gerdes, A., Hoefer, H.E.Lu-Hf and Sm-Nd geochronology and geothermobarmetry of the lithospheric mantle beneath the Gibeon kimberlite field, Namibia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, NamibiaDeposit - Gibeon
DS201212-0475
2012
Gerdes, A.Millonig, L.J., Gerdes, A., Groat, L.A.U Th Pb geochronology of meta-carbonatites and meta-alkaline rocks.Goldschmidt Conference 2012, abstract 1p.Canada, British ColumbiaMagmatism
DS201212-0476
2012
Gerdes, A.Millonig, L.J., Gerdes, A., Groat, L.A.U Th Pb geochronology of meta-carbonatites and meta-alkaline rocks in the southern Canadian Cordillera: a geodynamic perspective.Lithos, Vol. 152, pp. 202-217.Canada, British Columbia, AlbertaCarbonatite
DS201212-0652
2012
Gerdes, A.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Ultra depleted eclogites: residues of TTG melting.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, South AfricaDeposit - Bellsbank
DS201212-0653
2012
Gerdes, A.Shu, Q., Brey, G.P., Gerdes, A., Hofer, H.E., Seitz, H.M.Eclogites and garnet pyroxenites from the mantle: their age and ageing- two point isochrons, Sm-Nd and Lu-Hf closure temperatures, model ages.emc2012 @ uni-frankfurt.de, 1p. AbstractAfrica, South AfricaDeposit - Bellsbank
DS201212-0729
2012
Gerdes, A.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
DS201312-0312
2013
Gerdes, A.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
DS201312-0555
2013
Gerdes, A.Luchs, T., Brey, G.P., Gerdes, A., Hofer, H.E.The lithospheric mantle underneath the Gibeon kimberlite field ( Namibia): a mix of old and young components - evidence from Lu-Hf and Sm-Nd isotope systematics.Precambrian Research, Vol. 231, pp. 263-276.Africa, NamibiaDeposit - Gibeon
DS201312-0606
2013
Gerdes, A.Millonig, L.J., Gerdes, A., Groat, L.A.The effect of amphibolite facies metamorphism on the U-Th-Pb geochronology of accessory minerals from meta-carbonatites and associated meta-alkaline rocks.Chemical Geology, Vol. 353, pp. 199-209.MantleCarbonatite
DS201312-0820
2013
Gerdes, A.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Geochronological and geochemical constraints on the formation and evolution of the mantle beneath the Kaapvaal craton: Lu Hf and Sm Nd systematics of subcalcic garnets from highly depleted peridotites.Geochimica et Cosmochimica Acta, Vol. 113, pp. 1-20.Africa, South AfricaDeposit - Roberst Victor, Lace
DS201312-0821
2013
Gerdes, A.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Simultaneous mantle metasomatism, diamond growth and crustal events in the Archean and Proterozoic of South Africa.Goldschmidt 2013, AbstractAfrica, South AfricaMetasomatism
DS201312-0824
2013
Gerdes, A.Sieber, M., Brey, G.P., Seitz, H-M., Gerdes, A., Hoefer, H.E.The age of eclogitisation underneath the Kaapvaal craton - a composite xenolith from Roberts Victor.Goldschmidt 2013, 1p. AbstractAfrica, South AfricaDeposit - Roberts Victor
DS201312-0914
2013
Gerdes, A.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
DS201412-0367
2014
Gerdes, A.Hofmann, M., Linnemann, U., Hoffmann, K-H., Gerdes, A., Eckelmann, K., Gartner, A.The Namuskluft and Dreigratberg sections in southern Namibia ( Kalahari Craton, Gariep Belt): a geological history of Neoproterozoic rifting and recycling of cratonic crust during the dispersal of Rodinia until the amalgamation of Gondwana.International Journal of Earth Sciences, Vol. 103, pp. 1187-1202.Africa, NamibiaGeochronology
DS201412-0575
2014
Gerdes, A.Midende, G., Boulais, P., Tack, L., Melcher, F., Gerdes,A., Dewaele, S., Demaiffe, D., Decree, S.Petrography, geochemistry and U Pb zircon age of the Matongo carbonatite Massif ( Burundi): implication for the Neoproterozoic geodynamic evolution of Central Africa.Journal of African Earth Sciences, Vol. 100, pp. 656-674.Africa, BurundiCarbonatite
DS201412-0822
2014
Gerdes, A.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Mantle eclogites and garnet pyroxenites - the meaning of two point isochrons, Sm-Nd and Lu-Hf closure temperatures and the cooling of the subcratonic mantle.Earth and Planetary Science Letters, Vol. 389, pp. 143-154.MantleGeochronology
DS201502-0078
2014
Gerdes, A.Midende, G., Boulvais, P., Tack, L., Melcher, F., Gerdes, A., Dewaele, S., Demaiffe, D., Decree, S.Petrography, geochemistry and U-Pb zircon age of the Matongo carbonatite Massif ( Burundi): implication for the Neoproterozoic geodynamic evolution of Central Africa.Journal of African Earth Sciences, Vol. 100, pp. 656-674.Africa, BurundiCarbonatite
DS201509-0386
2015
Gerdes, A.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.
DS201511-1875
2015
Gerdes, A.Saha, L., Frei, D., Gerdes, A., Pat, J.K., Sarkar, S., Patole, V., Bhandari, A., Nasipuri, P.Crustal geodynamics from the Archean Bundelk hand craton, India: constraints from zircon U-Pb-Hf isotope studies.Geological Magazine, Rapid communication Oct. 14p.IndiaTectonics, geochronology

Abstract: A comprehensive study based on U-Pb and Hf isotope analyses of zircons from gneisses has been conducted along the western part (Babina area) of the E–W-trending Bundelkhand Tectonic Zone in the central part of the Archaean Bundelkhand Craton. 207Pb-206Pb zircon ages and Hf isotopic data indicate the existence of a felsic crust at ~ 3.59 Ga, followed by a second tectonothermal event at ~ 3.44 Ga, leading to calc-alkaline magmatism and subsequent crustal growth. The study hence suggests that crust formation in the Bundelkhand Craton occurred in a similar time-frame to that recorded from the Singhbhum and Bastar cratons of the North Indian Shield.
DS201602-0189
2016
Gerdes, A.Augstsson, C., Wilner, A.P., Rusing, T., Niemeyer, H., Gerdes, A., Adams, C.J., Miller, H.The crustal evolution of South America from a zircon Hf-isotope perspective.Terra Nova, In press availableSouth AmericaGeochronology

Abstract: Hf-isotope data of greater than 1100 detrital zircon grains from the Palaeozoic, south-central Andean Gondwana margin record the complete crustal evolution of South America, which was the predominant source. The oldest grains, with crustal residence ages of 3.8-4.0 Ga, are consistent with complete recycling of existing continental crust around 4 Ga. We confirm three major Archaean, Palaeoproterozoic (Transamazonian) and late Mesoproterozoic to early Neoproterozoic crust-addition phases as well as six igneous phases during Proterozoic to Palaeozoic time involving mixing of juvenile and crustally reworked material. A late Mesoproterozoic to early Neoproterozoic, Grenville-age igneous belt can be postulated along the palaeo-margin of South America. This belt was the basement for later magmatic arcs and accreted allochthonous microcontinents as recorded by similar crustal residence ages. Crustal reworking likely dominated over juvenile addition during the Palaeozoic era, and Proterozoic and Archaean zircons were mainly crustally reworked from the eroding, thickened Ordovician Famatinian arc.
DS201602-0234
2016
Gerdes, A.Saha, L., Frei, D., Gerdes, A., Pati, J.K., Sarkar, S., Patole, V., Bhandari, A., Nasipuri, P.Crustal geodynamics from the Archean Bundelk hand Craton, India: constraints from zircon U-Pb-Hf isotope studies.Geological Magazine, Vol. 153, 1, pp. 179-192.IndiaGeochronology, tectonics

Abstract: A comprehensive study based on U-Pb and Hf isotope analyses of zircons from gneisses has been conducted along the western part (Babina area) of the E-W-trending Bundelkhand Tectonic Zone in the central part of the Archaean Bundelkhand Craton. 207Pb-206Pb zircon ages and Hf isotopic data indicate the existence of a felsic crust at ~ 3.59 Ga, followed by a second tectonothermal event at ~ 3.44 Ga, leading to calc-alkaline magmatism and subsequent crustal growth. The study hence suggests that crust formation in the Bundelkhand Craton occurred in a similar time-frame to that recorded from the Singhbhum and Bastar cratons of the North Indian Shield.
DS201604-0591
2016
Gerdes, A.Augustsson, C., Willner, A.P., Rusing, T., Niemeyer, H., Gerdes, A., Adams, C.J., Miller, H.The crustal evolution of South America from a zircon Hf-isotope perspective.Terra Nova, Vol. 28, 2, pp. 128-137.South AmericaTectonics

Abstract: Hf-isotope data of >1100 detrital zircon grains from the Palaeozoic, south-central Andean Gondwana margin record the complete crustal evolution of South America, which was the predominant source. The oldest grains, with crustal residence ages of 3.8-4.0 Ga, are consistent with complete recycling of existing continental crust around 4 Ga. We confirm three major Archaean, Palaeoproterozoic (Transamazonian) and late Mesoproterozoic to early Neoproterozoic crust-addition phases as well as six igneous phases during Proterozoic to Palaeozoic time involving mixing of juvenile and crustally reworked material. A late Mesoproterozoic to early Neoproterozoic, Grenville-age igneous belt can be postulated along the palaeo-margin of South America. This belt was the basement for later magmatic arcs and accreted allochthonous microcontinents as recorded by similar crustal residence ages. Crustal reworking likely dominated over juvenile addition during the Palaeozoic era, and Proterozoic and Archaean zircon was mainly crustally reworked from the eroding, thickened Ordovician Famatinian arc.
DS201604-0592
2016
Gerdes, A.Aulbach, S., Gerdes, A., Vijoen, K.S.Formation of Diamondiferous kyanite eclogite in a subduction melange.Geochimica et Cosmochimica Acta, Vol. 179, pp. 156-176.Africa, South AfricaDeposit - Lace

Abstract: Diamond- and kyanite-bearing eclogites from the Lace kimberlite on the Kaapvaal craton have common picritic to gabbroic oceanic protoliths with bimineralic eclogites, lying on arrays of Eu? and ?REE that are consistent with accumulation and fractionation of plagioclase and olivine. However, they also show significant compositional differences, such as more grossular-rich garnet and aluminous clinopyroxene (cpx), which require the operation of additional processes. Their nature is elucidated using mineral major- and trace-element compositions, as well as Sr isotope ratios determined by in situ techniques.Highly variable major-element compositions across the co-genetic eclogite suites exert a strong effect on the trace-element distribution between garnet and cpx, whereby Sc, Ge, Sr, Y, Cd, REE, Th and U partition more strongly into garnet with increasing grossular-content. Thus, significant differences between the trace-element compositions of garnet can ensue from crystal-chemical effects alone, making their use as petrogenetic indicators potentially ambiguous. After correcting for these compositional effects, garnet in kyanite-/diamond eclogites, and in eclogites devoid of accessory minerals but with similar signatures, shows depletion (or dilution) in Sc, Ge, Y, In, Zr, Hf and the HREE, and enrichment in the LREE and Th compared to garnet in bimineralic eclogites. This is interpreted as the signature of a pelite-derived melt, which was transferred by addition of aluminous cpx that later exsolved kyanite and garnet, as observed in other aluminous eclogite suites. Continental input can explain initial (at 2.9 Ga) 87Sr/86Sr ? 0.714 measured in cpx in eleven samples with low 87Rb/86Sr (<0.01). The association of diamond with kyanite suggests that diamond formation is also linked to this event, possibly due to diamond formation by oxidation of reduced carbon, such as methane, and attendant reduction of Fe3+ in garnet. This model of sediment melt-oceanic crust interaction reconciles evidence for both low- and high-pressure igneous processes in some aluminous eclogites. We suggest that a subduction mélange is a favourable setting for the transfer of a sediment-derived signature into oceanic crust, leading to formation of diamondiferous kyanite-eclogites from bimineralic eclogites. Diapirism, fluxed by the presence of partial melt, may have facilitated dispersal of the eclogites in the lithosphere column, consistent with their widely varying equilibration pressures ranging from ?5 to 8 GPa.
DS201804-0688
2017
Gerdes, A.Forster, B., Aulbach, S., Symes, C., Gerdes, A., Hofer, H.E., Chacko, T.A reconnaissance study of Ti minerals in cratonic granulite xenoliths and their potential as recorders of lower crust formation and evolution.Journal of Petrology, Vol. 58, 10, pp. 2007-2034.Canada, Northwest Territoriesdeposit - Diavik

Abstract: A comprehensive petrographic and in situ major and trace element study of rutile, ilmenite and Ti-magnetite was undertaken in six lower crustal xenoliths of metabasaltic (?underplate) and metasedimentary (subduction) origin from the Diavik kimberlites (central Slave Craton, Canada). The aims of the study were to improve our understanding of trace element incorporation into these Ti-minerals, and to use these systematics to obtain insights into lower continental crust formation and evolution. Abundant (oxy)exsolution of titanomagnetite lamellae, blocky rutile, as well as minor pleonaste and zircon in ilmenite from metabasaltic granulites are proposed to reflect cooling from magmatic or metamorphic temperatures and subsequent secular mantle cooling. This explains the large spread in Zr-in-rutile temperatures (>200°C) and may partly be responsible for the substantial heterogeneity of other trace element concentrations in rutile and ilmenite. Even after accounting for trace element heterogeneity and modal uncertainties, mass-balance calculations indicate that both Ti and Nb in lower crustal granulites are largely controlled by rutile and ilmenite. Rutile U-Pb data define discordia arrays that yield upper intercept ages broadly coincident with the 1•27 Ga giant Mackenzie dike swarm event, suggesting reheating of the lower crust above the rutile U-Pb closure temperature, whereas lower intercept ages roughly correspond to the age of Cretaceous to Eocene kimberlite magmatism. Subsequent cooling led to partial resetting and data spread along the concordia. Closer inspection reveals that inter-grain concentrations of elements that are compatible in rutile (Nb, Ta, W, U), but highly incompatible in the abundant silicate minerals (in equilibrium with melt), are heterogeneous and contrast with the more homogeneous concentrations of the transition metals (NiO, V). This may indicate that local reaction partners for diffusive homogenization of these element concentrations were absent. Nb/Ta is also highly variable at the sample scale. This may be explained by prograde growth from high-Nb/Ta mineral precursors (e.g. biotite) in the metasedimentary granulites and crystallization of the protoliths to the metabasaltic granulites from a mafic magma that had experienced fractionation of ilmenite with low Nb/Ta in a crustal magma chamber. Thus, (Fe)-Ti minerals represent high field strength element ‘islands’ in the granulite silicate matrix. The lack of homogenization and persistence of high-energy grain boundaries, such as exsolution lamellae, further indicate that the lower continental crust remained essentially dry and did not recrystallize, possibly since Neoarchaean metamorphism.
DS201805-0935
2017
Gerdes, A.Aulbach, S., Sun, J., Tappe, S., Hofer, H.E., Gerdes, A.Volatile rich metasomatism in the cratonic mantle beneath SW Greenland: link to kimberlites and mid-lithospheric discontinuities.Journal of Petrology, Vol. 58, 12, pp. 2311-2338.Europe, Greenlandkimberlite

Abstract: The cratonic part of Greenland has been a hotspot of scientific investigation since the discovery of some of the oldest crust on Earth and of significant diamond potential in the underlying lithospheric mantle, the characterization of which remains, however, incomplete. We applied a detailed petrographic and in situ analytical approach to a new suite of fresh kimberlite-borne peridotite xenoliths, recovered from the North Atlantic craton in SW Greenland, to unravel the timing and nature of mantle metasomatism, and its link to the formation of low-volume melts (e.g. kimberlites) and to geophysically detectible discontinuities. Two types of mineralogies and metasomatic styles, occurring at two depth intervals, are recognized. The first type comprises lherzolites, harzburgites and dunites, some phlogopite-bearing, which occur from ?100-170?km depth. They form continuous trends towards lower mineral Mg# at increasing TiO2, MnO and Na2O and decreasing NiO contents. These systematics are ascribed to metasomatism by a hydrous silicate melt precursor to c. 150?Ma kimberlites, in the course of rifting, decompression and lithosphere thinning. This metasomatism was accompanied by progressive garnet breakdown, texturally evident by pyroxene-spinel assemblages occupying former coarse grains and compositionally evident by increasing concentrations of elements that are compatible in garnet (Y, Sc, In, heavy rare earth elements) in newly formed clinopyroxene. Concomitant sulphide saturation is indicated by depletion in Cu, Ni and Co. The residual, more silica-undersaturated and potentially more oxidizing melts percolated upwards and metasomatized the shallower lithospheric mantle, which is composed of phlogopite-bearing, texturally equilibrated peridotites, including wehrlites, showing evidence for recent pyroxene-breakdown. This is the second type of lithology, which occurs at ?90-110?km depth and is inferred to have highly depleted protoliths. This type is compositionally distinct from lherzolites, with olivine having higher Ca/Al, but lower Al and V contents. Whereas low Al may in part reflect lower equilibration temperatures, low V is ascribed to a combination of intrinsically more oxidizing mantle at lower pressure and oxidative metasomatism. The intense metasomatism in the shallow cratonic mantle lithosphere contrasts with the strong depletion recorded in the northwestern part of the craton, which at 590-550?Ma extended to >210?km depth, and suggests loss of ?40?km of lithospheric mantle, also recorded in the progressive shallowing of magma sources during the breakup of the North Atlantic craton. The concentration of phlogopite-rich lithologies in a narrow depth interval (?90-110?km) overlaps with a negative seismic velocity gradient that is interpreted as a mid-lithospheric discontinuity beneath western Greenland. This is suggested to be a manifestation of small-volume volatile-rich magmatism, which paved the way for Mesozoic kimberlite, ultramafic lamprophyre, and carbonatite emplacement across the North Atlantic craton.
DS201810-2292
2018
Gerdes, A.Abbo, A., Avigad, D., Gerdes, A.The lower crust of the Northern broken edge of Gondwana: evidence for sediment subduction and syn-Variscan anorogenic imprint from zircon U-Pb-Hf granulite xenoliths.Gondwana Research, Vol. 64, pp. 84-96.Europesubduction

Abstract: The continental basement in the Eastern Mediterranean represents the northern edge of Gondwana, which has been the site of repeated crustal accretion and has subsequently been modified by consecutive rifting events. We investigated the geologic and thermal history of the North Gondwana lower crust by examining the U-Pb-Hf isotope systematics in zircons within 6 mafic granulite xenoliths from Pliocene lava cone in North Israel. The lava cone protrudes through the platform cover that seals the late Neoproterozoic junction between the Arabian-Nubian basement to the South and the Cadomian basement exposed in the Taurides to the North. The mafic granulite xenoliths are composed of plagioclase + orthopyroxene + clinopyroxene ± garnet ± spinel ± secondary amphibole. U-Pb zircon ages from the granulites vary among the different samples with distinct zircon age populations at 400-1200 Ma, 170-350 Ma, and 3.6-4.2 Ma, attesting the lower crust preserves a prolonged thermal and igneous history. While 400-550 Ma U-Pb ages are interpreted to be the result of Pb loss, the wide scatter of zircon grains aged between 550 and 1200 Ma, alongside their diverse ?Hf(t) values (?25-+10), is an extraordinary evidence for the accretion of Neoproterozoic sediments into the North Gondwana arc root lower crust. The U-Pb-Hf signature of these zircons resembles Cadomian sediments of the Tauride block to the north, indicating southward (present coordinates) subduction under North Gondwana and possible accretion of fore-arc sediments to the lower crust through relamination in the latest Neoproterozoic. One xenolith contained metamorphic-shaped zircons aged 170-350 Ma with positive ?Hf values and Hf-TDM of 0.85 Ga interpreted to reflect Paleozoic recycling of the Neoproterozoic juvenile Arabian basement, which we consider to form a major component of the lower crust in the region. An overwhelming cluster of Carboniferous zircons concentrating at 305 Ma with exclusively negative ?Hf values around ?6, was retrieved from three xenoliths. Some of these zircons portrayed igneous textures and shape. While Carboniferous igneous activity is the hallmark of Western Europe's Variscan orogeny, the latter did not affect the southern rifted edge of Neo-Tethys where our xenoliths were retrieved. The Paleozoic age-Hf composition in our xenoliths is therefore interpreted to result from syn-Variscan recycling of Neoproterozoic sedimentary remains in the lower crust, and some degree of melting in a non-orogenic environment. Rather than with horizontal plate motions and orogeny, the Carboniferous zircon ages in the xenoliths appear to coalesce with significant vertical movements that created continental scale unconformities and a broad basin and swell architecture known to develop over the entire North Gondwana margin at that time. The Carboniferous aged zircons in northern Israel lower crustal xenoliths are therefore a unique gauge of the thermal perturbation that accompanied the large-scale mantle dynamics below the then passive North African margin of Gondwana, while Variscan orogenic accretion occurred on the Eurasian margin. These lower crustal granulites xenoliths therefore contain important information with respect to the nature of the lower crust under Israel, with implications on the geodynamic setting during the Cadomian and Variscan cycles.
DS201810-2321
2018
Gerdes, A.Ghobadi, M., Gerdes, A., Kogarko, L., Hoefer, H., Brey, G.In situ LA-ICPMS isotopic and geochronological studies on carbonatites and phoscorites from the Guli Massif, Maymecha-Kotuy, polar Siberia.Geochemistry International, Vol. 56, 8, pp. 766-783.Russia, Siberiacarbonatite

Abstract: In this study we present a fresh isotopic data, as well as U-Pb ages from different REE-minerals in carbonatites and phoscorites of Guli massif using in situ LA-ICPMS technique. The analyses were conducted on apatites and perovskites from calcio-carbonatite and phoscorite units, as well as on pyrochlores and baddeleyites from the carbonatites. The 87Sr/86Sr ratios obtained from apatites and perovskites from the phoscorites are 0.70308-0.70314 and 0.70306-0.70313, respectively; and 0.70310-0.70325 and 0.70314-0.70327, for the pyrochlores and apatites from the carbonatites, respectively. Furthermore, the in situ laser ablation analyses of apatites and perovskites from the phoscorite yield ?Nd from 3.6 (±1) to 5.1 (±0.5) and from 3.8 (±0.5) to 4.9 (±0.5), respectively; ?Nd of apatites, perovskites and pyrochlores from carbonatite ranges from 3.2 (±0.7) to 4.9 (±0.9), 3.9 (±0.6) to 4.5 (±0.8) and 3.2 (±0.4) to 4.4 (±0.8), respectively. Laser ablation analyses of baddeleyites yielded an eHf(t)d of +8.5 (± 0.18); prior to this study Hf isotopic characteristic of Guli massif was not known. Our new in situ ?Nd, 87Sr/86Sr and eHf data on minerals in the Guli carbonatites imply a depleted source with a long time integrated high Lu/Hf, Sm/Nd, Sr/Rb ratios. In situ U-Pb age determination was performed on perovskites from the carbonatites and phoscorites and also on pyrochlores and baddeleyites from carbonatites. The co-existing pyrochlores, perovskites and baddeleyites in carbonatites yielded ages of 252.3 ± 1.9, 252.5 ± 1.5 and 250.8 ± 1.4 Ma, respectively. The perovskites from the phoscorites yielded an age of 253.8 ± 1.9 Ma. The obtained age for Guli carbonatites and phoscorites lies within the range of ages previously reported for the Siberian Flood Basalts and suggest essentially synchronous emplacement with the Permian-Triassic boundary.
DS201903-0497
2019
Gerdes, A.Aulbach, S., Sun, J., Tappe, S., Gerdes, A.Effects of multi-stage rifting and metasomatism on HSE 187 Os 188 Os systematics of the cratonic mantle beneath SW Greenland. KimberlitesContributions to Mineralogy and Petrology, Vol. 174, 23p.Europe, Greenlandmetasomatism

Abstract: We report highly siderophile element (HSE) abundances and Re-Os isotope compositions, obtained by isotope dilution induc-tively coupled plasma mass spectrometry, of olivine separates from a suite of multiply metasomatised peridotite xenoliths entrained in kimberlites from SW Greenland. Combined with petrographic and compositional observations on accessory base metal sulphides (BMS), the results reveal new insights into the chemical, physical and mineralogical effects of multi-stage rifting and associated melt percolation on the Archaean lithospheric mantle. Refertilised lherzolites are dominated by rare to frequent small (tens of µm) BMS inclusions in olivine, whereas modally metasomatised phlogopite-bearing lherzolite and wehrlites have higher proportions of more Ni-rich BMS, including abundant large interstitial grains (hundreds of µm). The olivine separates display depleted HSE systematics with Primitive Upper Mantle (PUM)-normalised Pd/Ir of 0.014-0.62, and have both depleted and enriched 187 Os/ 188 Os (0.1139-0.2724) relative to chondrite that are not correlated with 187 Re/ 188 Os. Four out of ten olivine separates retain similarly depleted Os corresponding to Re-depletion model ages of 2.1-1.8 Ga. They may reflect Palaeoproterozoic refertilisation (lherzolitisation) during Laurentia plate assembly, with re-introduction of clinopyroxene and Os-rich BMS into the originally refractory mantle lithosphere by asthenosphere-derived basaltic melts, followed by recrystallisation and occlusion in olivine. Unradiogenic Os is observed regardless of lithology, including from peridotites that contain abundant interstitial BMS. This reflects addition of Os-poor BMS (<< 1 ppm) during more recent wehrlitisation and phlogopite-introduction, and control of the Os isotopic signature by older Os-rich BMS that precipitated from the basaltic melt. Depletions in compatible HSE (< 0.5 × PUM for Ru, Ir, Os) in all, but one olivine separate reflect nugget effects (amount of depleted vs. metasomatic BMS inclusions) and/or loss due to sulphide dissolution into oxidising small-volume melts that invaded the lithosphere during recurrent rifting, the latter supported by similar depletions in published bulk peridotite data. Combined, these multiple metasomatic events destroyed all vestiges of Mesoarchaean or older inheritance in the olivine separates investigated here, and highlight that caution is needed when interpreting Proterozoic Os model ages in terms of Proterozoic lithosphere stabilisation.
DS201904-0716
2019
Gerdes, A.Aulbach, S., Tappe, S., Gerdes, A.Effects of multi-stage rifting and metasomatism on HSE-187Os/188Os systematic of the cratonic mantle beneath SW Greenland.Contributions to Mineralogy and Petrology, Vol. 174, 23p.Europe, Greenlandkimberlites

Abstract: We report highly siderophile element (HSE) abundances and Re-Os isotope compositions, obtained by isotope dilution inductively coupled plasma mass spectrometry, of olivine separates from a suite of multiply metasomatised peridotite xenoliths entrained in kimberlites from SW Greenland. Combined with petrographic and compositional observations on accessory base metal sulphides (BMS), the results reveal new insights into the chemical, physical and mineralogical effects of multi-stage rifting and associated melt percolation on the Archaean lithospheric mantle. Refertilised lherzolites are dominated by rare to frequent small (tens of µm) BMS inclusions in olivine, whereas modally metasomatised phlogopite-bearing lherzolite and wehrlites have higher proportions of more Ni-rich BMS, including abundant large interstitial grains (hundreds of µm). The olivine separates display depleted HSE systematics with Primitive Upper Mantle (PUM)-normalised Pd/Ir of 0.014-0.62, and have both depleted and enriched 187Os/188Os (0.1139-0.2724) relative to chondrite that are not correlated with 187Re/188Os. Four out of ten olivine separates retain similarly depleted Os corresponding to Re-depletion model ages of 2.1-1.8 Ga. They may reflect Palaeoproterozoic refertilisation (lherzolitisation) during Laurentia plate assembly, with re-introduction of clinopyroxene and Os-rich BMS into the originally refractory mantle lithosphere by asthenosphere-derived basaltic melts, followed by recrystallisation and occlusion in olivine. Unradiogenic Os is observed regardless of lithology, including from peridotites that contain abundant interstitial BMS. This reflects addition of Os-poor BMS (<
DS201906-1269
2019
Gerdes, A.Aulbach, S., Hofer, H.E., Gerdes, A.High Mg and Low Mg mantle eclogites from Koidu (West African Craton) linked by Neoproterozoic ultramafic melt metasomatism of subducted Archean plateau-like oceanic crust.Journal of Petrology, Vol. 60, 4, pp. 723-754.Africa, Sierra Leonedeposit - Koidu

Abstract: Bimineralic eclogites and pyroxenites (n?=?75?±?accessory rutile, ilmenite, sulphide, apatite) from the Koidu kimberlite (West African Craton) were investigated for mineral major and trace elements and mineral Sr-Nd isotope compositions to constrain (1) the nature and age of their basaltic to picritic protoliths, and (2) the effect, timing and source of mantle metasomatism. Consistent with published work, samples are grouped into low-Mg eclogites with Mg# from 0•49 to 0•73 (median 0•59; n?=?40) and high-Mg eclogites with Mg# from 0•60 to 0•88 (median 0•75; n?=?14), plus pyroxenites [clinopyroxene Na/(Na + Ca) <0•2; n?=?8] and gabbroic eclogites and pyroxenite (Eu/Eu* of reconstructed bulk-rocks >1•05; n?=?8), with five unclassifiable samples. Reconstructed low-Mg and gabbroic eclogites have major and trace element systematics (Eu/Eu*-heavy rare earth elements-Y) indicating crustal protolith crystallisation, confirming an origin as subducted oceanic crust. Their high FeO contents at MgO >?10?wt % require an Fe-rich source, the high melt productivity of which led to the formation of thicker crust, perhaps in a plateau-like setting. This is consistent with SiO2-MgO relationships indicating differentiation at ?0•5?GPa. Unradiogenic Sr in some clinopyroxene (87Sr/86Sr of 0•7010-0•7015), combined with light rare earth element (LREE) depletion relative to normal mid-ocean ridge basalt (N-MORB) for the majority of samples (average N-MORB-normalised Nd/Yb of unmetasomatised samples = 0•51), suggests eclogitisation and partial melt loss in the Neoarchaean, possibly coeval with and parental to 2•7?Ga overlying continental crust. Most reconstructed high-Mg eclogites and some pyroxenites formed by metasomatic overprinting of low-Mg eclogites and gabbroic eclogites, as indicated by the preservation of positive Eu anomalies in some samples, and by the Mg-poorer composition of included versus matrix minerals. Coupled enrichment in MgO, SiO2 and Cr2O3 and in incompatible elements (Sr, LREE, Pb, Th and U) is ascribed to metasomatism by a kimberlite-like, small-volume, carbonated ultramafic melt, mediated by addition of clinopyroxene from the melt (i.e. stealth metasomatism). Strontium-Nd isotope systematics suggest a Neoproterozoic age for this metasomatic event, possibly linked to Rodinia break-up, which facilitated intrusion of asthenospheric carbonated melts with an ocean island basalt-like 87Sr/86Sri of ?0•7035. Cretaceous kimberlite magmatism (including Koidu), with more radiogenic 87Sr/86Sr (?0•7065, intermediate between Kaapvaal kimberlites and orangeites), may have been partially sourced from associated Neoproterozoic metasomes. The presence of diamonds in low-Mg eclogites, but absence in high-Mg eclogites, indicates the diamond-destructive nature of this event. Nevertheless, the moderate proportion of affected eclogites (?35%) suggests preservation of a sizeable diamond-friendly mantle eclogite reservoir beneath Koidu.
DS202004-0499
2020
Gerdes, A.Aulbach, S., Masuyeau, M., Gerdes, A., Garber, J.M.Ultramafic carbonated melt- and-auto -metasomatism in mantle eclogites: compositional effects and geophysical consequences.Geochemistry, Geophysics, Geosystems, in press available, 41p. PdfMantleeclogites
DS202006-0910
2020
Gerdes, A.Aulbach, S., Viljoen, K.S., Gerdes, A.Diamondiferous and barren eclogites and pyroxenites from the western Kaapvaal craton record subduction processes and mantle metasomatism respectively.Lithos, in press available 52p. PdfAfrica, South Africadeposit - Doomkloof-Sover

Abstract: Mineral major and trace elements combined with Sr isotopes of clinopyroxene are used to unravel the origins and evolution of mantle eclogite and pyroxenite xenoliths from the Doornkloof-Sover orangeite dike (western Kaapvaal craton), and to investigate the generation and destruction of diamond in these rocks. Two different eclogite types are present: (1) MgO-poor eclogites (MgO?=?7.3 to 14.5?wt%; n?=?43) with accessory diamond ± corundum and kyanite; garnet grossular content (median Ca#?=?0.25) and clinopyroxene jadeite content (0.39). Reconstructed bulk rocks are LREE-depleted (median La 0.29?ppm) and have low median Cr2O3 (0.06?wt%) and incompatible trace-element contents (e.g. Sr, Zr, Ba, Pb, Th), and high Li and transition metal abundances. Some are characterised by stepped REE patterns or steep slopes in the MREE, similar to eclogites affected by interaction with dehydration fluids generated in subduction zones. These fluids may also have deposited diamond in typically reducing eclogite assemblages at diamond-stable pressures. (2) MgO-rich eclogites and pyroxenites (MgO?=?14.0 to 20.0?wt%; n?=?29), which are barren and enriched in LREE (median La 1.39?ppm), Cr2O3 (0.25?wt%) and incompatible trace elements, with lower Li and transition metal abundances than the MgO-poor group. These are typical signatures of carbonated ultramafic melt metasomatism in the mantle lithosphere. Strontium isotopic compositions vary widely in both groups, but high Cr2O3 and Ba contents are dominantly associated with 87Sr/86Sr?>?0.7055. This reflects interaction with metasomatic agents remobilised from ancient lithospheric metasomes, which eventually gave rise to regional orangeite magmatism. The presence of strong positive Eu anomalies in both groups, including two pyroxenites, requires low-pressure igneous protoliths, presumably derived from a ca. 3?Ga spreading ridge, as reported for other eclogite materials from the western Kaapvaal craton. Based on the proportions of MgO-poor and -rich eclogites and pyroxenites, approximately 40% of the diamond inventory were destroyed by mantle metasomatism centred at ~135?±?15?km depth, overlapping a low-velocity anomaly (mid-lithospheric discontinuity). Two diamondiferous orangeites ?20?km from Doornkloof-Sover contain significantly different eclogite xenolith populations: At Newlands, MgO-poor diamondiferous eclogites are present in addition to barren MgO-rich ones and pyroxenite, suggesting that the host orangeite sampled a source region equally affected by diamond-destructive mantle metasomatism, whereas at Bellsbank, all eclogites are MgO-poor and LREE-depleted. This may explain higher diamond grades reported for this locality compared to Newlands or Doornkloof-Sover.
DS202006-0937
2020
Gerdes, 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.
DS202006-0948
2020
Gerdes, A.Rossetti, F., Lucci, F., Theye, T., Bouybaouenne, M., Gerdes, A., Optiz, J., Dini, A., Lipp, C.Hercynian anatexis in the envelope of the Beni Bousera peridotites ( Alboran Domain, Morroco): implications for the tectono-metamorphic evolution of the deep crustral roots of the Mediterranean region.Gondwana Research, Vol. 83, pp. 157-162. pdfAfrica, Moroccoperidotites

Abstract: The metamorphic core of the Betic-Rif orogenic chain (Alboran Domain) is made up of lower crustal rocks forming the envelope of the Ronda (Spain) and Beni Bousera (Morocco) peridotites. The deepest sections of the crustal envelopes are made of migmatitic granulites associated with diffuse acidic magmatic products, making these exposure and ideal site to investigate the textural and petrological connection between crustal anatexis and granite magmatism in the contintental crust. However, still debated is the timing of intracrustal emplacement of the peridotite bodies, with models proposing either Alpine (early Miocene) or Hercynian ages, and still uncertain is the linkage between peridotite emplacement and crustal anatexis. In this study, by combining rock textures with whole-rock geochemistry, metamorphic thermobarometry, the U-Pb zircon geochronology and the analysis of the garnet and zircon REE chemistry, we document the P-T-t evolution of the granulite facies migmatites that form the immediate envelope of the Beni Bousera peridotites of the Rif belt. A main episode of Permo-Carboniferous (ca. 300-290?Ma) deep crustal anatexis, melt extraction and migration is documented that we link to the crustal emplacement of the Beni Bousera peridotites during collapse of the Hercynian orogen. Correlation at a regional scale suggests that the Beni-Bousera section can be tentatively correlated with the pre-Alpine (Permo-Carboniferous) basement units tectonically interleaved within the orogenic structure of the Alpine chain. The results of this study provide ultimate constraints to reconstruct the tectono-metamorphic evolution of the Alboran Domain in the Western Mediterranean and impose re-assessment of the modes and rates through which Alpine orogenic construction and collapse occurred and operated in the region.
DS202107-1094
2021
Gerdes, A.Consuma, G., Aulbach, S., Braga, R., Martin, L.A.J., Tropper, P., Gerdes, A., Fiorentini, M.L.Multi-stage sulfur and carbon mobility in fossil continental subduction zones: new insights from carbonate-bearing orogenic peridotites. *** Not specific to diamondsGeochimica et Cosmochimica Acta, Vol. 306, pp. 143-170. pdfEurope, Italysubduction

Abstract: The volatile transfer in subduction zones and the role of sulfate as a vector for the mobilization of oxidized components from down-going slabs remain hotly debated issues. Orogenic spinel and garnet peridotite lenses from the Ulten Zone (Eastern Alps, Italy), exhumed as part of felsic metamorphic terranes in continental collision zones, bear witness to mass transfer processes in these pivotal environments. In this study, we carried out a multi-method investigation of mantle sulfides coexisting with four generations of carbonates, indicating coupled sulfur and carbon mobility throughout the peridotites’ metamorphic evolution as part of the Variscan subduction architecture. Detailed petrography, bulk rock measurements, in situ chemical and geochemical analyses of sulfides as well as Sr isotope analyses of associated clinopyroxene and amphibole are combined with the aim to constrain the origin, nature and effect of multiple C-O-H-S-bearing fluids and melts the peridotites interacted with. The first, pre-peak, metasomatic pulse (Stage 1) is represented by an H2S-CO2-bearing melt from the subduction-modified hot mantle wedge, which formed a pyroxenite layer hosting matrix pentlandite with ?34S of +2.77‰. Matrix carbonates occasionally occur in the coarse-grained peridotite under eclogite-facies conditions (Stage 2), with heavier ?34S (up to +3.43‰), radiogenic Sr (87Sr/86Srclinopyroxene > 0.7052) and elevated Pb abundances. These are ascribed to interaction with isotopically heavy melts carrying recycled crustal component, permissive of, but not requiring, involvement of oxidized S species. Conversely, isotopically lighter matrix pentlandite (?34S = ?1.62 to +0.67‰), and radiogenic Sr in amphibole (87Sr/86Sr = 0.7056) and associated dolomite (published data) from fine-grained garnet-amphibole peridotites may point to involvement of H2S-CO2-bearing crustal fluids, which variably equilibrated with the mantle before interacting with the peridotites. The post-peak Stage 3 marks the entrapment of peridotites into a tectonic mélange. Here, kelyphitization of garnet is catalyzed by further ingress of a S-bearing fluid (?34S = ?0.38‰), while carbonate veining with occasional sulfides bear witness to channelized fluid flow. Sulfide and amphibole grains in retrogressed spinel peridotites reveal the highest contents of fluid-mobile elements (As, Sb) and 87Sr/86Sramphibole up to 0.7074, suggesting late interactions with isotopically heavy crustal fluids at high fluid-rock ratios. Textural observations indicate that, during Stage 4, serpentinization of peridotites at low ƒS2 played an active role not only in CO2 release by conversion of dolomite to calcite + brucite intergrowths, but also in local removal of 32S during the final exhumation stage. Late channelized sulfur remobilization is evidenced by the serpentine + magnetite (±millerite ± calcite) vein carrying > 300 ppm S. Overall, the relatively narrow range of sulfur isotope composition (?34S = ?1.62 to +3.76‰) is indicative of limited interaction with isotopically heavy crustal liquids, and points to a subordinate role of subduction-derived sulfate throughout the extended fluid(melt)/rock evolution of the Ulten Zone peridotites, first in the mantle wedge and then as part of a tectonic mélange.
DS202111-1775
2021
Gerdes, A.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.
DS202203-0347
2022
Gerdes, A.Ghobadi, M., Brey, G.P., Gerdes, A., Hofer, H.E., Keller, J.Accessories in Kaiserstuhl carbonatites and related rocks as accurate and faithful recorders of whole rock age and isotopic composition.International Journal of Earth Science, Vol. 111, 2, 16p.Europe, Germanycarbonatite

Abstract: The accessories perovskite, pyrochlore, zirconolite, calzirtite and melanite from carbonatites and carbonate-rich foidites from the Kaiserstuhl are variously suited for the in situ determination of their U-Pb ages and Sr, Nd- and Hf-isotope ratios by LA-ICP-MS. The 143Nd/144Nd ratios may be determined precisely in all five phases, the 176Hf/177Hf ratios only in calzirtite and the 87Sr/86Sr ratios in perovskites and pyrochlores. The carbonatites and carbonate-rich foidites belong to one of the three magmatic groups that Schleicher et al. (1990) distinguished in the Kaiserstuhl on the basis of their Sr, Nd and Pb isotope ratios. Tephrites, phonolites and essexites (nepheline monzogabbros) form the second and limburgites (nepheline basanites) and olivine nephelinites the third. Our 87Sr/86Sr isotope data from the accessories overlap with the carbonatite and olivine nephelinite fields defined by Schleicher et al. (1990) but exhibit a much narrower range. These and the ?Nd and ?Hf values plot along the mantle array in the field of oceanic island basalts relatively close to mid-ocean ridge basalts. Previously reported K-Ar, Ar-Ar and fission track ages for the Kaiserstuhl lie between 16.2 and 17.8 Ma. They stem entirely from the geologically older tephrites, phonolites and essexites. No ages existed so far for the geologically younger carbonatites and carbonate-rich foidites except for one apatite fission track age (15.8 Ma). We obtained precise U-Pb ages for zirconolites and calzirtites of 15.66, respectively 15.5 Ma (±?0.1 2?) and for pyrochlores of 15.35?±?0.24 Ma. Only the perovskites from the Badberg soevite yielded a U-P concordia age of 14.56?±?0.86 Ma while the perovskites from bergalites (haüyne melilitites) only gave 206Pb/238U and 208Pb/232Th ages of 15.26?±?0.21, respectively, 15.28?±?0.48 Ma. The main Kaiserstuhl rock types were emplaced over a time span of 1.6 Ma almost 1 million years before the carbonatites and carbonate-rich foidites. These were emplaced within only 0.32 Ma.
DS1988-0250
1988
Gerdes, R.A.Gerdes, R.A.Geophysical appraisal of the Echunga district, with reference tomineralizationSouth Australia Department of Mineral Resources, Review, Vol. 156, pp. 27-35GlobalGeophysics, Echunga Magnetics
DS2002-0554
2002
Gerel, O.Gerel, O., Munkhtsengel, B., Enkhituvshin, H.Mushgai Khudag and Bayan Khoshuu complexes in south Mongolia: an example of potassic magmatism with carbonatites.11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 25.MongoliaCarbonatite, Geochronology
DS200612-0446
2005
Gerel, O.Gerel, O., Munkhtsengel, B., Enkhtuvshin, H., Iizumi, Sh.Mushgai Khudag and Bayan Khosuu volcanic plutonic alkaline complexes with REE Ta Nb Fe carbonatite mineralization.Seltmann, Gerel, Kirwin eds. Geodynamics and Metallogeny of Mongolia with emphasis on copper, gold, pp. 215-225.Asia, MongoliaCarbonatite, rare earths
DS2000-0531
2000
Gerel, P.Kovalenko, V., Antipin, V., Gerel, P., Olka, P.Central Asia - a key area for understanding plate tectonic processesIgc 30th. Brasil, Aug. abstract only 1p.GlobalTectonics, Mongol-Okhotsk Belt
DS1997-0545
1997
Gerhard, D.A.Isachsen, Y.W., Gerhard, D.A., Hurowitz, J.Digital map of Adirondack dikesGeological Society of America (GSA) Abstracts, Vol. 29, No. 1, March 17-19, p. 54.GlobalDikes
DS1988-0051
1988
Gerhard, L.Berendsen, P., Borcherding, R.M., Doveton, J., Gerhard, L.Texaco Persch # 1, Washington County, Kansas:preliminary geologic report of pre-Phanerozoic rocksKansas Geological Survey Open File Rept, No. 88-22, 116pKansasMidcontinent, Tectonics
DS1991-0565
1991
Gerhard, L.C.Gerhard, L.C., Anderson, S.B., Fischer, D.W.Petroleum geology of the Wiliston Basinin: Interior cratonic basins, ed. Leighton, M.W. et al., American Association of Petroleum Geologists Memoir No. 51, Chpater 29, pp. 507-559SaskatchewanBasin, Geology ( specific to petroleum but useful)
DS2001-0378
2001
Gerhard, L.C.Gerhard, L.C., Harrison, W.E., Hanson, B.M.Introduction and overview of global climate changeAmerican Association of Petroleum Geologists (AAPG) Book, pp.1-15.GlobalClimatology - brief overview
DS2002-1277
2002
Gericke, B.Poujol, M., Robb, L.J., Anhaeusser, C.R., Gericke, B.Geochronologic constraints on the evolution of the Kaapvaal Craton, South AfricaEconomic Geology Research Institute, EGRU Wits, Information Circular, No. 360, 37p.South AfricaGeochronology, craton, terrane, magmatism - not specific to diamonds
DS2003-1098
2003
Gericke, B.Poujol, M., Robb, L.J., Anhaeusser, C.R., Gericke, B.A review of the geochronological constraints on the evolution of the Kaapvaal CratonPrecambrian Research, Vol. 127, 1-2, Nov. pp. 181-213.South AfricaGeochronology
DS200412-1573
2003
Gericke, B.Poujol, M., Robb, L.J., Anhaeusser, C.R., Gericke, B.A review of the geochronological constraints on the evolution of the Kaapvaal Craton, South Africa.Precambrian Research, Vol. 127, 1-2, Nov. pp. 181-213.Africa, South AfricaGeochronology
DS200712-0357
2007
Gerike, B.L.Gerike, B.L., Filatov, A.P., Gerike, P.B., Klishin, V.Concept of rock breaking working element of an underground kimberlite ore mining machine.Journal of Mining Science, Vol. 42, 6, pp. 610-616.TechnologyMining
DS200712-0357
2007
Gerike, P.B.Gerike, B.L., Filatov, A.P., Gerike, P.B., Klishin, V.Concept of rock breaking working element of an underground kimberlite ore mining machine.Journal of Mining Science, Vol. 42, 6, pp. 610-616.TechnologyMining
DS1960-1056
1968
Gerina, I.F.Zhukov, V.V., Gerina, I.F.Kainozoiskie Almazonosnye Anabaro-olenekskogo MezhdurechyaLeningrad: Niiga., 143P.RussiaKimberlite, Kimberley, Janlib, Geology
DS1970-0083
1970
Geringer, G.J.Geringer, G.J.Mineralogiese Aspekte Van die Kimberliet Van die RovicmynBloemfontein: Msc. Thesis University Oranje-vrystaat., South AfricaKimberlite, Mineralogy
DS1990-0563
1990
Geringer, G.J.Geringer, G.J., Lucdick, D.J.Middle-Proterozoic calc-alkaline, shoshonitic volcanism along the Eastern margin of the Namaqua Mobile Belt, South Africa- implications for tectonic evolution areaSouth African Journal of Geology, Vol. 93, No. 2, pp. 389-399South AfricaShoshonite, Tectonics
DS1998-0503
1998
Geringer, G.J.Geringer, G.J., Schocj, A.E., Zhuravlev, D.Geochemical and isotopic characteristics of different types of anorthosite in the Namaqua mobile beltChem. Geol, Vol. 145, No. 1-2, Mar. 6, pp. 17-South AfricaNamaqua mobile belt, Geochemistry
DS1986-0287
1986
Gerlach, D.C.Gerlach, D.C., Cliff, R.A., Davies, G.R.The Cape Verde Islands: isotopic and trace element characteristicsGeological Society of America (GSA) Abstract Volume, Vol. 18, No. 6, p. 611. (abstract.)GlobalGeochronology
DS1986-0343
1986
Gerlach, D.C.Hart, S.R., Gerlach, D.C., White, M.W.A possible new Strontium neodymium lead mantle array and consequences for mantle mixingGeochimica et Cosmochimica Acta, Vol. 50, No. 7, July pp. 1551-1557GlobalMantle
DS1988-0251
1988
Gerlach, D.C.Gerlach, D.C., Cliff, R.A., Davies, G.R., Norry, M., Hodgson, N.Magma sources of the Cape Verdes Archipelago: isotopic and trace elementconstraintsGeochimica et Cosmochimica Acta, Vol. 52, No. 12, pp. 2979-2992GlobalBasanite, Carbonatite, Melilitite, Rare earths
DS200912-0245
2009
Gerlings, J.Gerlings, J., Funck, T., Jackson, R.H., Louden, K.E., Klingelhofer, F.Seismic evidence for plume derived volcanism during formation of the continental margin in southern Davis Strait and northern Labrador Sea.Geophysical Journal International, Vol. 176, 3, pp. 980-994.CanadaPlume
DS201212-0711
2012
Gerlings, J.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
DS1989-0506
1989
German, L.L.German, L.L.Pulsation of the earth and parallel dikes in ophiolitesInternational Geology Review, Vol. 31, No. 8, August pp. 767-779RussiaOphiolites, Dykes
DS1987-0248
1987
Germann, A.Germann, A., Marker, m A., Friefrich, G.The alkaline complex of Jacupiranga, Sao Paulo/Brasil;petrology and genetic considerationsSymposium on Latin American Geosciences, Zentralblatt fuer geologie und, Vol. 1987, No. 7-8, pp. 807-818BrazilAlkaline rocks, Carbonatite
DS1994-0613
1994
Germann, K.Germann, K., Schwarz, T., Wipki, M.Mineral deposit formation in Phanerozoic sedimentary basins of northeast Africa:the contribution of weatheringGeologische Rundschau, Vol. 83, No. 4, Dec. pp. 787-798AfricaPhanerozoic, Weathering, alluvials, laterites
DS1993-0535
1993
Germanoski, D.Germanoski, D., Schum, S.A.Changes in braided river morphology resulting from aggradation anddegradationJournal of Geology, Vol. 101, No. 3, July, pp. 451-466GlobalRiver morphology, Alluvials, Geomorphology, River morphology -general
DS1970-0914
1974
Germs, G.J.B.Germs, G.J.B.The Nama Group in Southwest Africa and its Relationship To the Pan African Geosyncline.Journal of Geology, Vol. 82, PP. 301-317.Southwest Africa, NamibiaRegional Geology
DS1995-0628
1995
Germs. G.J.B.Germs. G.J.B.The Neoproterozoic of southwestern Africa, with emphasis on platform stratigraphy and paleontologyPrecambrian Research, Vol. 73, pp. 137-151Africa, Namibia, West AfricaStratigraphy
DS200612-1342
2006
GernonSparks, R.S.J., Baker, Brooker, Brown, Field, Fontana, Gernon, Kavanagh, Shumacher, Stripp, Walter, Walters, White, WindsorDynamical constraints on kimberlite volcanism,Emplacement Workshop held September, 5p. abstractGlobalMagmatism, water, stages
DS200612-0183
2006
Gernon, T.Brown, R.J., Gernon, T., Tshutlhedi, J.Insights into the eruption of the Jwaneng Centre lobe kimberlite pipe.Emplacement Workshop held September, 5p. extended abstractAfrica, BotswanaDeposit - Jwaneng - lithofacies assemblages
DS200612-1505
2006
Gernon, T.Walters, A.L., Phillips, J.C., Brown, R.J., Field, M., Gernon, T., Stripp, G., Sparks, R.S.J.The role of fluidisation in the formation of volcaniclastic kimberlite: grain size observations and experimental investigation.Journal of Volcanology and Geothermal Research, in press availableAfrica, South AfricaDeposit - Venetia, explosive eruption, fluidization
DS200812-0146
2008
Gernon, T.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
DS200812-0147
2008
Gernon, T.Brown, R.J., Gernon, T., Stiefenhofer, J., Field, M.Geological constraints on the eruption of the Jwaneng Centre kimberlite pipe, Botswana.Journal of Volcanology and Geothermal Research, Vol. 174, 1-3, pp. 195-208.Africa, BotswanaEplosive eruption, phreatomagmatism, fluidisation
DS201212-0233
2012
Gernon, T.Gernon, T., Brown, R.J., Tait, M.A., Hincks, T.K.The origin of pellatal lapilli in explosive kimberlite eruptions.Nature Communcations, May 7p.Africa, South Africa, LesothoDeposit - Venetia, Letseng-la-Terae
DS201212-0694
2012
Gernon, T.Sparks, R.S.J., Buisman, I., Brooker, R., Brown, R.J., Field, M., Gernon, T., Kavanagh,J., Ogilvie-Harris, R., Schumacher, J.C.Dynamics of kimberlite magam ascent, intrusion and eruption.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractGlobalDiamond genesis
DS201412-0096
2014
Gernon, T.Campeny, M., Mangas, J., Melgarejo, J.C., Bambi, A., Alfonso, P., Gernon, T., Manuel, J.The Catanga extrusive carbonatites ( Kwanza Sul, Angola): an example of explosive carbonatitic volcanism.Bulletin of Volcanology, Vol. 76, pp. 818-Africa, AngolaCarbonatite
DS200612-0447
2006
Gernon, T.M.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
DS200612-0448
2006
Gernon, T.M.Gernon, T.M., Sparks, R.S.J., Brown, R.J., Field, M.Gas segregation pipes in kimberlite: evidence for fluidisation at Orapa south pipe, Botswana.Emplacement Workshop held September, 5p. extended abstractAfrica, BotswanaDeposit - Orapa - fluidisation, structure
DS200812-0397
2008
Gernon, T.M.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
DS200812-0398
2008
Gernon, T.M.Gernon, T.M., Sparks, R.S.J., Field, M.Degassing structures in volcaniclastic kimberlite: examples from southern African kimberlite pipes.Journal of Volcanology and Geothermal Research, Vol. 174, 1-3, pp. 186-194.Africa, South AfricaFluidisation,pyroclastic flows, Orapa. Venetia. Letseng
DS200912-0218
2009
Gernon, T.M.Field, M., Gernon, T.M., Mock, A., Walters, A., Sparks, R.S.J., Jerram, D.A.Variations of olivine abundance and grain size in the Snap lake kimberlite intrusion, Northwest Territories, Canada: a possible proxy for diamonds.Lithos, In press available 13p.Canada, Northwest TerritoriesDeposit - Snap Lake
DS200912-0224
2009
Gernon, T.M.Fontana, G.P.,MacNiocaill, C., Brown, R.J., Sparks, S.R., Field, M., Gernon, T.M.Emplacement temperatures of pyroclastic and colcaniclastic deposits in kimberlite pipes in southern Africa: new constraints from paleomagnetic measurementsGAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyAfrica, Botswana, South AfricaDeposit - AK1, Orapa, K1, K2 Venetia
DS200912-0246
2009
Gernon, T.M.Gernon, T.M., Field, M., Sparks, S.J.Depositional processes in a kimberlite crater: the Upper Cretaceous Orapa South pipe.(Botswana).Sedimentology, Vol. 56, 3, pp. 623-643.Africa, BotswanaGeology - pyroclastic flow
DS200912-0247
2009
Gernon, T.M.Gernon, T.M., Fontana, G., Field, M., Sparks, R.S.J., Brown, R.J., Niocaill, C.M.Pyroclastic flow deposits from a kimberlite eruption: the Orapa south crater, Botswana.Lithos, In press available 13p.Africa, BotswanaDeposit - Orapa
DS200912-0248
2009
Gernon, T.M.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
DS200912-0249
2009
Gernon, T.M.Gernon, T.M., Sparks, R.S., Field, M., Ogilvie-Harris, R.C.Geological constraints on the emplacement of the Snap lake kimberlite dyke, NW Territories, Arctic Canada.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyCanada, Northwest TerritoriesDeposit - Snap Lake
DS200912-0547
2009
Gernon, T.M.Ogilvie-Harris, R.C., Sparks, R.S., Field, M., Gernon, T.M.The geochemistry of the Snap Lake kimberlite dyke, Northwest Territories: phlogopite and spinel.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyCanada, Northwest TerritoriesDeposit - Snap Lake
DS201212-0234
2012
Gernon, T.M.Gernon, T.M., Brown, R.J., Tait, N., Hinks, T.K.The origin of pellatal lapilli in explosive kimberlite eruptions.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractTechnologyPetrology
DS201212-0235
2012
Gernon, T.M.Gernon, T.M., Field, M., Sparks, R.S.J.Geology of the Snap Lake kimberlite intrusion, NWT, Canada: field observations and their interpretation.Journal of the Geological Society, Vol. 169, pp. 1-16.Canada, Northwest TerritoriesDeposit - Snap Lake
DS201507-0312
2015
Gernon, T.M.Gernon, T.M., Spence, S., Trueman, C.N., Taylor, R.N., Rohling, E., Hatter, S.J., Harding, I.C.Emplacement of Cabezo Maria lamproite volcano (Miocene) SE Spain.Bulletin of Volcanology, Vol. 77, 6, pp. 52-Europe, SpainLamproite
DS201604-0608
2016
Gernon, T.M.Gernon, T.M., Hincks, T.K., Tyrell, T., Rohling, E.J., Palmer, M.R.Snowball Earth ocean chemistry driven by extensive ridge volcanism during Rodinia breakup.Nature Geoscience, Vol. 9, 3, pp. 242-248.Gondwana, RodiniaAlkalic

Abstract: During Neoproterozoic Snowball Earth glaciations, the oceans gained massive amounts of alkalinity, culminating in the deposition of massive cap carbonates on deglaciation. Changes in terrestrial runoff associated with both breakup of the Rodinia supercontinent and deglaciation can explain some, but not all of the requisite changes in ocean chemistry. Submarine volcanism along shallow ridges formed during supercontinent breakup results in the formation of large volumes of glassy hyaloclastite, which readily alters to palagonite. Here we estimate fluxes of calcium, magnesium, phosphorus, silica and bicarbonate associated with these shallow-ridge processes, and argue that extensive submarine volcanism during the breakup of Rodinia made an important contribution to changes in ocean chemistry during Snowball Earth glaciations. We use Monte Carlo simulations to show that widespread hyaloclastite alteration under near-global sea-ice cover could lead to Ca2+ and Mg2+ supersaturation over the course of the glaciation that is sufficient to explain the volume of cap carbonates deposited. Furthermore, our conservative estimates of phosphorus release are sufficient to explain the observed P:Fe ratios in sedimentary iron formations from this time. This large phosphorus release may have fuelled primary productivity, which in turn would have contributed to atmospheric O2 rises that followed Snowball Earth episodes.
DS201902-0284
2019
Gernon, T.M.Keller, C.B., Husson, J.M., Mitchell, R.N., Bottke, W.F., Gernon, T.M., Boehnke, P., Bell, E.A., Swanson-Hysell, N.L., Peters, S.E.Neoproterozoic glacial origin of the Great Unconformity.PNAS, pnas.org/cqi/doi/10.1073/ pnas.1804350116 10p.Mantlegeomorphology

Abstract: The Great Unconformity, a profound gap in Earth’s stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great Unconformity has remained elusive. Here we show that the Great Unconformity is associated with a set of large global oxygen and hafnium isotope excursions in magmatic zircon that suggest a late Neoproterozoic crustal erosion and sediment subduction event of unprecedented scale. These excursions, the Great Unconformity, preservational irregularities in the terrestrial bolide impact record, and the first-order pattern of Phanerozoic sedimentation can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of 3-5 vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.
DS201902-0297
2019
Gernon, T.M.Mazourel, S., Ghent, R.R., Bottke, W.F., Parker, A.H., Gernon, T.M.Earth and Moon impact flux increased at the end of the Paleozoic. Craters almost abscent older than 650 mln years. Kimberlite ages used.Science, Vol. 363, 6424, Jan. 18, pp. 253-257.Globalgeochronology
DS201908-1798
2019
Gernon, T.M.Mzrouei, S., Ghent, R.R., Bottke, W.F., Parker, A.H., Gernon, T.M.Response to comment on "Earth and Moon impact flux increased at the end of the Paleozoic".Science, Vol. 365, 6450, 8p. eaaw9895 July 19MantleCraton

Abstract: Hergarten et al. interpret our results in terms of erosion and uncertain calibration, rather than requiring an increase in impact flux. Geologic constraints indicate low long-term erosion rates on stable cratons where most craters with diameters of ?20 kilometers occur. We statistically test their proposed recalibration of the lunar crater ages and find that it is disfavored relative to our original calibration.
DS202004-0538
2020
Gernon, T.M.Taylor, R.N., Favila-Harris, P., Branney, M.J., Farley, E.M.R., Gernon, T.M., Palmer, M.R.Dynamics of chemically pulsing mantle plume.Earth and Planetary Science Letters, Vol. 537, 116182 14p. PdfMantlehotspot

Abstract: Upwelling plumes from the deep mantle have an impact on the Earth's surface for tens to hundreds of millions of years. During the lifetime of a mantle plume, periodic fluctuations in its composition and temperature have the potential to generate changes in the nature and volume of surface volcanism. We constrain the spatial and temporal scale of compositional changes in a plume using high-resolution Pb isotopes, which identify chemical pulses emerging from the Canary Islands hotspot over the last ?15 million years (Myr). Surface volcanism spanning ? 400 km along the island chain changes composition systematically and synchronously, representing a replenishment of the plume head by a distinct mantle flavour on timescales of 3-5 Myr. These low-frequency compositional changes are also recorded by individual volcanoes, and comprise a sequence of closely-spaced isotopic trajectories. Each trajectory is maintained for ?1 Myr and is preceded and followed by ?0.3 Myr transitions to magmas with distinct isotope ratios. Relatively sharp transitions between periods of sustained isotopic stability require discrete yet coherent heterogeneities rising at speeds of ?100-200 km Myr?1 and extending for ?150 km vertically in the conduit. The long-term synchronous changes require larger scale isotopic domains extending ?600 km vertically through in the plume stem. These observations demonstrate that plumes can chemically “pulse” over short and long-timescales reflecting the characteristics and recycling history of the deep mantle.
DS202007-1144
2020
Gernon, T.M.Haddock, D., Manya, S., Brown, R.J., Jones, T.J., Wadsworth, F.B., Dobson, K.J., Gernon, T.M.Syn-eruptive agglutination of kimberlite volcanic ash. PyroclastsVolcanica, Vol. 3, 1, pp. 169-182. PdfAfrica, Tanzaniadeposit - Igwisi Hills

Abstract: Pyroclastic deposits of the Holocene Igwisi Hills kimberlite volcanoes, Tanzania, preserve unequivocal evidence for rapid, syn-eruptive agglutination. The unusual pyroclasts are composed of ash-sized particles agglutinated to each other by thin necks. The textures suggest the magma was disrupted into droplets during ascent. Collisions between particles occurred within a volcanic plume and on deposition within the conduit to form a weakly agglutinated, porous pyroclastic deposit. Theoretical considerations indicate that agglutination occurred over short timescales. Agglutinated clasts were entrained into weak volcanic plumes and deposited around the craters. Our results support the notion that agglutination can occur during kimberlite eruptions, and that some coherent, dense rocks in ancient kimberlite pipes interpreted as intrusive rocks could instead represent agglutinated pyroclastic rocks. Differentiating between agglutinated pyroclastic rocks and effusive or intrusive rocks in kimberlite pipes is important because of the potential effects that pyroclastic processes might have on diamond concentrations in deposits.
DS202011-2040
2020
Gernon, T.M.Haddock, D., Manya, S., Brown, R.J., Jones, T.J., Wadsworth, F.B., Dobson, K.J., Gernon, T.M.Syn-eruptive agglutination of kimberlite volcanic ash.Volcanica, 15p. PdfAfrica, Tanzaniadeposit - Igwisi Hills kimberlite

Abstract: Pyroclastic deposits of the Holocene Igwisi Hills kimberlite volcanoes, Tanzania, preserve unequivocal evidence for rapid, syn-eruptive agglutination. The unusual pyroclasts are composed of ash-sized particles agglutinated to each other by thin necks. The textures suggest the magma was disrupted into droplets during ascent. Collisions between particles occurred within a volcanic plume and on deposition within the conduit to form a weakly agglutinated, porous pyroclastic deposit. Theoretical considerations indicate that agglutination occurred over short timescales. Agglutinated clasts were entrained into weak volcanic plumes and deposited around the craters. Our results support the notion that agglutination can occur during kimberlite eruptions, and that some coherent, dense rocks in ancient kimberlite pipes interpreted as intrusive rocks could instead represent agglutinated pyroclastic rocks. Differentiating between agglutinated pyroclastic rocks and effusive or intrusive rocks in kimberlite pipes is important because of the potential effects that pyroclastic processes might have on diamond concentrations in deposits.
DS201212-0236
2012
Gernon, T.M.I.Gernon, T.M.I., Ogilvie-Harris, R.C., Sparks, R.S.J.,Field, M.Emplacement of the Snap Lake kimberlite intrusion, Northwest Territories, Canada.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Northwest TerritoriesDeposit - Snap Lake
DS1989-0122
1989
Gernov, P.Yu.Biryukov, V.M., Gernov, P.Yu., Ivanov, G.I., Kosygin, Yu.A.First diamond finds in plutonic xenoliths at the eastern margin of the Siberian craton #1Doklady Academy of Sciences USSR, Earth Science Section, Vol. 305, No. 2, March-April pp. 122-125RussiaXenoliths -plutonic, Diamonds
DS201911-2524
2019
Gerocs, T.Gerocs, T.The transformation of African-Russian economic relations in the multipolar world-system.Review of African Political Economy, Vol. 46, pp. 317-335.Africa, RussiaNews item - economics

Abstract: Despite the historical legacy of the Soviet Union, the Russian Federation’s economic presence in Africa today is minuscule in comparison to that of the West or China. The aim of this Briefing is to provide a framework for the trajectory of African-Russian economic ties in the changing international environment. Although the economic, trade and investment affairs could develop more complementarity, it is still an open question whether African countries benefit from the deepening economic ties or whether these inhibit local socio-economic development.
DS1988-0198
1988
Gerrard, A.J.Ehlen, J., Gerrard, A.J.Bibliography on the chemical weathering of granitic rocksNational Technical Information Service AD A 200, 157/6, 29p. approx. $ 13.95USGlobalBibliography -granitic weathering
DS1987-0072
1987
Gerrard, D.L.Bowley, H.J., Gerrard, D.L.Method for assessing diamond qualityPatent PCT International Appl. 87 03963 Al *July 2, 1987, GlobalRaman spectrometry
DS1988-0074
1988
Gerrard, D.L.Bowley, H.J., Gerrard, D.L.Methods and apparatus for determining the color type of diamondsBp Patent Pct International Appl. 88 05534 A1, July 28, GlobalRaman diamond color type determination, Diamond morphology -colou
DS1960-0048
1960
Gerrard, I.Gerrard, I.A Report on the Sampling of the Bed of the Upper Makloutsi River and of the Gravels in the Vicinity.Geological Survey Bechuanaland Protectorate, (UNPUBL.)BotswanaDiamond Prospecting
DS1960-0345
1963
Gerrard, I.Gerrard, I.The Geology of the Foley Area. an Explanation of Quarter Sheet 2127c. in the Report for the Year 1959-1960.Geological Survey Bechuanaland Protectorate, PP. 35-48.BotswanaDiamond Prospecting
DS1950-0389
1958
Gerrard, I.M.Gerrard, I.M.The Olivine Melilitites from the Western CapeCape Town: Msc. Thesis, University Cape Town., 106P.South Africa, Cape ProvinceGeology, Petrography, Melnoite
DS1999-0250
1999
Gerrie, V.Gerrie, V.Borehole geophysics in kimberlites. ( slide copies only)Assocation of Exploration Geologists (AEG) 19th. Diamond Exploration Methods Case Histories, pp. 34-7.GlobalKimberlite, Geophysics - borehole, Quantec
DS201604-0636
2016
Gerrit de Kock, B.Thomas, R.J, Spencer, C., Bushi, A.M., Baglow, N., Gerrit de Kock, B., Hortswood, M.S.A., Hollick, L., Jacobs, J., Kajara, S., Kaminhanda, G., Key, R.M., Magana, Z., McCourt, M.W., Momburi, P., Moses, F., Mruma, A., Myamilwa, Y., Roberts, N.M.W., HamisiGeochronology of the centra Tanzania craton and its southern and eastern orogenic margins.Precambrian Research, in press available 57p.Africa, TanzaniaGeochronology

Abstract: Geological mapping and zircon U-Pb/Hf isotope data from 35 samples from the central Tanzania Craton and surrounding orogenic belts to the south and east allow a revised model of Precambrian crustal evolution of this part of East Africa. The geochronology of two studied segments of the craton shows them to be essentially the same, suggesting that they form a contiguous crustal section dominated by granitoid plutons. The oldest orthogneisses are dated at ca. 2820 Ma (Dodoma Suite) and the youngest alkaline syenite plutons at ca. 2610 Ma (Singida Suite). Plutonism was interrupted by a period of deposition of volcano-sedimentary rocks metamorphosed to greenschist facies, directly dated by a pyroclastic metavolcanic rock which gave an age of ca. 2725 Ma. This is supported by detrital zircons from psammitic metasedimentary rocks, which indicate a maximum depositional age of ca. 2740 Ma, with additional detrital sources 2820 and 2940 Ma. Thus, 200 Ma of episodic magmatism in this part of the Tanzania Craton was punctuated by a period of uplift, exhumation, erosion and clastic sedimentation/volcanism, followed by burial and renewed granitic to syenitic magmatism. In eastern Tanzania (Handeni block), in the heart of the East African Orogen, all the dated orthogneisses and charnockites (apart from those of the overthrust Neoproterozoic granulite nappes), have Neoarchaean protolith ages within a narrow range between 2710 and 2630 Ma, identical to (but more restricted than) the ages of the Singida Suite. They show evidence of Ediacaran "Pan-African" isotopic disturbance, but this is poorly defined. In contrast, granulite samples from the Wami Complex nappe were dated at ca. 605 and ca. 675 Ma, coeval with previous dates of the "Eastern Granulites" of eastern Tanzania and granulite nappes of adjacent NE Mozambique. To the south of the Tanzania Craton, samples of orthogneiss from the northern part of the Lupa area were dated at ca. 2730 Ma and clearly belong to the Tanzania Craton. However, granitoid samples from the southern part of the Lupa "block" have Palaeoproterozoic (Ubendian) intrusive ages of ca. 1920 Ma. Outcrops further south, at the northern tip of Lake Malawi, mark the SE continuation of the Ubendian belt, albeit with slightly younger ages of igneous rocks (ca. 1870-1900 Ma) which provide a link with the Ponte Messuli Complex, along strike to the SE in northern Mozambique. In SW Tanzania, rocks from the Mgazini area gave Ubendian protolith ages of ca. 1980-1800 Ma, but these rocks underwent Late Mesoproterozoic high-grade metamorphism between 1015 and 1040 Ma. One granitoid gave a crystallisation age of ca. 1080 Ma correlating with known Mesoproterozoic crust to the east in SE Tanzania and NE Mozambique. However, while the crust in the Mgazini area was clearly one of original Ubendian age, reworked and intruded by granitoids at ca. 1 Ga, the crust of SE Tanzania is a mixed Mesoproterozoic terrane and a continuation from NE Mozambique. Hence the Mgazini area lies at the edge of the Ubendian belt which was re-worked during the Mesoproterozoic orogen (South Irumide belt), providing a further constraint on the distribution of ca. 1 Ga crust in SE Africa. Hf data from near-concordant analyses of detrital zircons from a sample from the Tanzania Craton lie along a Pb-loss trajectory (Lu/Hf = 0), extending back to ?3.9 Ga. This probably represents the initial depleted mantle extraction event of the cratonic core. Furthermore, the Hf data from all igneous samples, regardless of age, from the entire study area (including the Neoproterozoic granulite nappes) show a shallow evolution trend (Lu/Hf = 0.028) extending back to the same mantle extraction age. This implies the entire Tanzanian crust sampled in this study represents over 3.5 billion years of crustal reworking from a single crustal reservoir and that the innermost core of the Tanzanian Craton that was subsequently reworked was composed of a very depleted, mafic source with a very high Lu/Hf ratio. Our study helps to define the architecture of the Tanzanian Craton and its evolution from a single age-source in the early Eoarchaean.
DS1950-0064
1951
Gerryts, E.Gerryts, E.The Geology of the Kimberlites at the Premier (transvaal) Diamond Mines, South Africa.Montreal: Ph.d. Thesis, Mcgill University, South Africa, TransvaalKimberlite, Mineralogy, Petrology
DS1960-0551
1965
Gerryts, E.Gerryts, E.West End Diamond MineSelection Trust International Report, JULY 30TH., 4P.Sierra Leone, West AfricaGeology
DS1970-0084
1970
Gerryts, E.Gerryts, E.Diamond Prospecting by Geophysical Methods: a Review of Current Practice.Geological Survey of Canada (GSC) Economic Geology Report, No. 26, PP. 439-446.GlobalKimberlite, Geophysics, Ground Mag, Koffiefontein
DS1970-0516
1972
Gerryts, E.Gerryts, E.Diamond Prospecting by Geophysical Methods- a Review of Current Practice.Selection Trust In House Report., 22P.South Africa, Sierra Leone, West Africa, MaliGeophysics, Kimberlite
DS1984-0300
1984
Gerryts, E.Gerryts, E.A Visit to Guinea- West AfricaGeological Society of South Africa Quarterly NEWS Bulletin., Vol. 28, No. 1, MARCH P. 24.West Africa, GuineaTravelogue, History
DS1988-0252
1988
Gerryts, E.Gerryts, E.Memories of Mwadui in the 1950's - recollections of William son DiamondsIndiaqua, No. 49 1988/I, pp. 21-23, 25-26, 27-31TanzaniaHistory
DS1988-0253
1988
Gershon, M.Gershon, M., Allen, L.E., Manley, G.Application of a new approach for drillholes location optimizationInternational Journal of Surface Mining, Vol. 2, pp. 27-31. Database # 17471GlobalDrilling, Geostatistics
DS2000-0660
2000
GerstenbergerMingram, B., TrumBulletin, R.B., Littman, S., GerstenbergerA petrogenetic study of anorogenic felsic magmatism in the Cretaceous Paresis ring complex: evidence of mixingLithos, Vol. 54, No. 1-2, Oct. pp. 1-22.NamibiaCrust and mantle derived components, Geochronology
DS201112-0360
2011
Gertner, I.Gertner, I., Tishin, P., Vrublevskii, V., Sazonov, A., Zvyagina, E., Kolmakov, Y.Neoproterozoic alkaline igneous rocks, carbonatites and gold deposits of the Yenisei Ridge, central Siberia: evidence of mantle plume activity and late collision...Resource Geology, Vol. 61, 4, pp. 316-343.Russia, SiberiaTectonics - carbonatites
DS1988-0527
1988
Gertner, I.E.Osipov, P.V., Makarenko, N.A., Korchagin, S.A., Gertner, I.E.New alkaline gabbroid ore bearing massif in Kuznetsk Alatau.(Russian)Geologii i Geofiziki, (Russian), No. 11, (346) November pp. 79-82RussiaAlkaline rocks
DS2000-0992
2000
Gertner, I.F.Vrublevsky, V.V., Gertner, I.F., Anoshin, G.N.Geochemistry of ultrapotassic rocks from Gonry Altai South SiberiaIgc 30th. Brasil, Aug. abstract only 1p.Russia, SiberiaTectonics - rifting, Minette - geochemistry
DS2003-1434
2003
Gertner, I.F.Vrublevskii, V.A., Gertner, I.F., Zhuravlev, D.Z., Makarenko, N.A.The Sm Nd isotopic age and source of comagmatic alkaline mafic rocks andDoklady Earth Sciences, Vol. 391A, 6, July-August, pp. 832-5.RussiaGeochronology
DS200412-2065
2003
Gertner, I.F.Vrublevskii, V.A., Gertner, I.F., Zhuravlev, D.Z., Makarenko, N.A.The Sm Nd isotopic age and source of comagmatic alkaline mafic rocks and carbonatites of Kuznetsk Alatau.Doklady Earth Sciences, Vol. 391A, 6, July-August, pp. 832-5.RussiaGeochronology
DS200412-2066
2004
Gertner, I.F.Vrublevskii, V.V., Zhuravlev, D.Z., Gertner, I.F., Krupchatnikov, V.I., Vladimirov, A.G., Rikhvanov, L.P.Sm Nd isotopic systematics of alkaline rocks and carbonatites from the Edelveis Complex, Northern Chuya Range, Gornyi Altai.Doklady Earth Sciences, Vol. 397, 6, July-August pp. 870-874.RussiaGeochronology
DS200512-1155
2004
Gertner, I.F.Vrublevskii, V.V., Gertner, I.F., Polyakov, Izokh, Krupchatnikov, Travin, VoitenkoAr Ar isotopic age of lamproite dikes of the Chua Complex, Gornyi Altai.Doklady Earth Sciences, Vol. 399A, 9, Nov-Dec. pp. 1252-55.RussiaLamproite
DS200612-0449
2006
Gertner, I.F.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
DS200612-1495
2005
Gertner, I.F.Vrublevskii, V.V., Gertner, I.F.Origin of carbonatite bearing complexes from fold systems: isotopic evidence for mantle crust interaction.Problems of Sources of deep magmatism and plumes., pp. 38-58.MantleGeochronology
DS200612-1496
2006
Gertner, I.F.Vrublevskii, V.V., Voitenko, N.N., Romanov, A.P., Polyakov, G.V., Izokh, A.E., Gertner, I.F., Krupchatnikov, V.I.Magma sources of Triassic lamproites of Gornyi Altai and Taimyr: Sr and Nd isotope evidence for plume lithosphere interaction.Doklady Earth Sciences, Vol. 405A 9, pp. 1365-1367.RussiaLamproite
DS201112-1095
2011
Gertner, I.F.Vrublevskii, V.V., Reverdatto, V.V., Izokh, A.E., Gertner, I.F., Yudin, D.S., Tishin, P.A.Neoproterozoic carbonatite magmatism of the Yenesei Ridge, central Siberia: 40AR39Ar geochronology of the Penchenga rock complex.Doklady Earth Sciences, Vol. 437, 2, pp. 443-448.Russia, SiberiaCarbonatite
DS201112-0199
2010
Gervasconi, F.Conceicao, R.V., Green, D.H., Lenz, C., Gervasconi, F., Drago, S.Derivation of potassic magmas by decompression melting of phlogopite+pargasite lherzolite.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 74.MantleMetasomatism
DS201112-0200
2010
Gervasconi, F.Conceicao, R.V., Lenz, C., Gervasconi, F., Drago, S.Origin of the potassium in the Earth-Moon system and contribution for the K-rich rocks.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 73.MantleMelting
DS201412-0002
2014
Gervasoni, F.Adriao, A., Conceicao, R., Carniel, L., Gervasoni, F.Chemical and isotopic evidences of mantle source heterogeneity in the RosaRio do Sul kimberlite province.Goldschmidt Conference 2014, 1p. AbstractSouth America, BrazilDeposit - RosaRio do Sul
DS201705-0829
2017
Gervasoni, F.Gervasoni, F., Klemme, S., Rohrbach, A., Grutzner, T., Berndt, J.Experimental constraints on mantle metasomatism caused by silicate and carbonate melt.Lithos, Vol. 282-283, pp. 173-186.MantleCarbonatite

Abstract: Metasomatic processes are responsible for many of the heterogeneities found in the upper mantle. To better understand the metasomatism in the lithospheric mantle and to illustrate the differences between metasomatism caused by hydrous silicate and carbonate-rich melts, we performed various interaction experiments: (1) Reactions between hydrous eclogite-derived melts and peridotite at 2.2-2.5 GPa and 900-1000 °C reproduce the metasomatism in the mantle wedge above subduction zones. (2) Reactions between carbonate-rich melts and peridotite at 2.5 GPa and 1050-1000 °C, and at 6 GPa and 1200-1250 °C simulate metasomatism of carbonatite and ultramafic silicate-carbonate melts in different regions of cratonic lithosphere. Our experimental results show that partial melting of hydrous eclogite produces hydrous Si- and Al-rich melts that react with peridotite and form bi-mineralic assemblages of Al-rich orthopyroxene and Mg-rich amphibole. We also found that carbonate-rich melts with different compositions react with peridotite and form new metasomatic wehrlitic mineral assemblages. Metasomatic reactions caused by Ca-rich carbonatite melt consume the primary peridotite and produce large amounts of metasomatic clinopyroxene; on the other hand, metasomatism caused by ultramafic silicate-carbonate melts produces less clinopyroxene. Furthermore, our experiments show that ultramafic silicate-carbonate melts react strongly with peridotite and cause crystallization of large amounts of metasomatic Fe-Ti oxides. The reactions of metasomatic melts with peridotite also change the melt composition. For instance, if the carbonatite melt is not entirely consumed during the metasomatic reactions, its melt composition may change dramatically, generating an alkali-rich carbonated silicate melt that is similar in composition to type I kimberlites.
DS201706-1072
2017
Gervasoni, F.Gervasoni, F., Klemme, S., Rohrbach, A., Grutzner, T., Berndt, J.Experimental constraints on the stability of baddeleyite and zircon in carbonate and silicate carbonate melts.American Mineralogist, Vol. 102, pp. 860-866.carbonatite

Abstract: Carbonatites are rare igneous carbonate-rich rocks. Most carbonatites contain a large number of accessory oxide, sulfide, and silicate minerals. Baddeleyite (ZrO2) and zircon (ZrSiO4) are common accessory minerals in carbonatites and because these minerals host high concentrations of U and Th, they are often used to determine the ages of formation of the carbonatite. In an experimental study, we constrain the stability fields of baddeleyite and zircon in Ca-rich carbonate melts with different silica concentrations. Our results show that SiO2-free and low silica carbonate melts crystallize baddeleyite, whereas zircon only crystallizes in melts with higher concentration of SiO2. We also find that the zirconsilicate baghdadite (Ca3ZrSi2O9) crystallizes in intermediate compositions. Our experiments indicate that zircon may not be a primary mineral in a low-silica carbonatite melt and care must be taken when interpreting zircon ages from low-silica carbonatite rocks.
DS201903-0548
2019
Gervasoni, F.Vieira Conceicao, R., Colombo Carniel, L., Jalowitski, T., Gervasoni, F., Grings Cedeno, D.Geochemistry and geodynamic implications on the source of Parana-Etendeka Large Igneous Province evidenced by the late 128 Ma Rosario-6 kimberlite, southern Brazil.Lithos, Vol. 328-329, pp. 130-145.South America, Brazildeposit - Rosario-6

Abstract: The Rosário-6 is a non-diamondiferous hypabyssal kimberlite located above the Rio de la Plata craton and near the south-eastern edge of the Paraná Basin, in southern Brazil. It is petrographically an inequigranular texture, macrocrystal kimberlite, fresh and the groundmass exhibits a microporphyritic texture and round megacrysts of olivine, which are derived from disaggregated mantle xenoliths. Olivine is also present as macrocrysts, microphenocrysts and in the groundmass together with phlogopite and apatite. These microphenocrysts are immersed in a groundmass of olivine, monticellite, phlogopite, CaTiO3-perovskite, apatite, Mg-chromite and Mg-ulvöspinel and melilite. A mesostasis assemblage of phlogopite, melilite, soda melilite, akermanite and calcium carbonate is segregated from the groundmass. Its geochemical signature is similar to those of transitional kimberlites of Kaapvaal Craton, South Africa, and the U-Pb ages of ~ 128 Ma on perovskite reveal that Rosário-6 kimberlite post-dates the main pulse of volcanism in the Paraná-Etendeka Large Igneous Province (LIP). The high Ti content of some minerals, such as Mg-chromite, Mg-ulvöspinel, phlogopite and melilite, and the presence of perovskite suggest a Ti-rich source. The petrographic, geochemical and isotopic data indicate that the Rosário-6 kimberlite source is a depleted mantle metasomatized by H2O-rich fluids, CO2-rich and silicate melts derived from the recycling of an ancient subducted oceanic plate (eclogite) before the South Atlantic opening. Although several authors indicate the influence of Tristan da Cunha plume for the generation of alkaline magmatism associated to the Paraná-Etendeka flood basalts, our data demonstrates that Tristan da Cunha plume has no chemical contribution to the generation of Rosário-6 kimberlite, except by its thermal influence.
DS202008-1402
2020
Gervasoni, F.Jalowitzki, T., Gervasoni, F., Sumino, H., Klemme, S., Berndt, J., Dalla Costa, M., Fuck, R.A.Plume subduction events recorded by KS2 kimberlite indicator minerals from Juina, Brazil.Goldschmidt 2020, 1p. AbstractSouth America, Brazil, Mato Grossodeposit - Juina

Abstract: The Cretaceous Juína Kimberlite Province (JKP, 95-92 Ma) is located in the southwest of the Amazonian Craton, northwest of Mato Grosso, Brazil. Here we present new geochemical and isotopic data of garnet (n=187) and zircon (n=25) megacrysts collected from the KS2 kimberlite. The magmatic zircon megacrysts have U-Pb ages of 92.1 ± 0.7 Ma. The chondrite-normalized rare earth element (REE) patterns (LREE
DS1990-0911
1990
Gervilla, F.Leblanc, M., Curras, J., Gervilla, F., Temagoult, A., Torres-RuizLherzolite related mineralizationsTerra, Abstracts of International Workshop Orogenic Lherzolites and Mantle Processes, Vol. 2, December abstracts p. 133AlpsLherzolite, Mineralogy
DS2001-0802
2001
Gervilla, F.Morishita, T., Arai, S., Gervilla, F.high pressure aluminous mafic rocks from the Ronda peridotite massif, significance of sapphirine corunduM.Lithos, Vol. 57, No. 2-3, June pp. 143-61.Globalultra high pressure (UHP), Deposit - Ronda massif
DS200612-0289
2006
Gervilla, F.Crespo, E., Luque, F.J., Rodas, M., Wada, H., Gervilla, F.Graphite sulphide deposits in Ronda and Beni Bousera peridotites ( Spain and Morocco) and the origin of carbon in mantle derived rocks.Gondwana Research, Vol. 9, 3, pp. 279-290.Europe, Spain, Africa, MoroccoPeridotite
DS201312-0320
2013
Gervilla, F.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
Gervilla, F.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
DS201312-0574
2013
Gervilla, F.Marchesi, C., Garrido, C.J., Bosch, D., Bodinier, J-L., Gervilla, F., Hidas, K.Mantle refertilization by melts of crustal derived garnet pyroxenite: evidence from the Ronda Peridotite massif, southern Spain.Earth and Planetary Interiors, Vol. 362, pp. 66-75.Europe, SpainRonda - pyroxenite. Melts
DS201412-0548
2014
Gervilla, F.Marchesi, C., Dale, C.W., Garrdo, C.J., Pearson, D.G., Bosch, D., Bodinier, J-L., Gervilla, F., Hidas, K.Fractionation of highly siderophile elements in refertilized mantle: implications for the Os isotope composition of basalts.Earth and Planetary Science Letters, Vol. 400, pp. 33-44.MantleRonda peridotite
DS201510-1768
2015
Gerya, I.T.Gerya, I.T.Tectonic overpressure and underpressure in lithospheric tectonics and metamorphism.Journal of Metamorphic Geology, Vol. 33, 8, pp. 785-800.MantleTectonics

Abstract: The lithostatic pressure concept is most commonly applied on a geological scale for lithospheric processes and related evolution of metamorphic rock complexes. Here, various aspects of non-lithostatic overpressure and underpressure phenomena in lithospheric tectonics and metamorphism are reviewed on the basis of recently published literature. The main conclusion from this short review is that these phenomena certainly exist in nature on all time and space scales including geological ones. They are, in particular, responsible for some geological processes, which are otherwise difficult to explain, such as downward water suction into the interior of subducting slabs. Magnitudes of overpressure and underpressure are strongly variable and may potentially reach up to ±100% of the lithostatic pressure and up to a GPa-level. These magnitudes depend mainly on the rheology of deforming rocks and on the nature of related tectonic process. Rheological heterogeneity of deforming rock units, which is common in nature, has a tendency to enhance overpressure and underpressures. Large overpressure can typically be expected in rheologically strong (dry) bending rock units, in particular in the mantle lithosphere. However, rheological weakness of rocks and small local deviatoric stresses do not guarantee the absence of large overpressures in these rocks. Therefore, the influence of significant tectonic overpressure and/or underpressure cannot be excluded for any metamorphic complex a priori but should be instead tested by exploring realistic thermomechanical models for envisaged tectono-metamorphic scenarios. Many lithospheric rocks subjected to large overpressures and underpressures cannot be studied as they do not exhume to the surface. Some controversy exists concerning overpressure magnitudes for the ultrahigh-pressure (UHP) rocks and several conflicting hypotheses are proposed, which need to be thoroughly tested in the future. In this respect, the Alpine region may offer a unique opportunity for the testing of geological-scale overpressures in (U)HP rocks by combining structural-geological and petrological data with realistic lithospheric-scale numerical modelling.
DS200712-0025
2007
Gerya, T.Arcay, D., Gerya, T., Tackley, P.Magma generation and transport subduction zones: numerical simulations of chemical, thermal and mechanical coupling during magma ascent by porous flow.Goldschmidt 2007 abstracts, 1p. abstract p. A32.MantleMagmatism
DS201012-0285
2010
Gerya, T.Honda, S., Gerya, T., Zhu, G.A simple three dimensional model of thermo-chemical convection in the mantle wedge.Earth and Planetary Science Letters, Vol. 290, 3-4, pp. 311-316.MantleGeothermometry
DS201012-0718
2010
Gerya, T.Sizova, E., Gerya, T., Brown, M., Perchuk, L.L.Subduction styles in the Precambrian: insight from numerical experiments.Lithos, Available in press, formatted 21p.MantleSubduction, tectonics
DS201112-0361
2011
Gerya, T.Gerya, T.Geodynamic regimes of continental crust growth and lithosphere reworking in subduction zones.Goldschmidt Conference 2011, abstract p.910.MantleRecycling of dense magmatic residue
DS201212-0660
2012
Gerya, T.Sizova,E., Gerya, T., Brown, M.Exhumation mechanisms of melt bearing ultrahigh pressure crustal rocks during collision of spontaneously moving plates.Journal of Metamorphic Geology, Vol. 30, 9, pp. 927-955.MantleUHP
DS201212-0661
2012
Gerya, T.Sizoya, E., Gerya, T., Brown, M.Exhumation mechanisms of melt bearing ultrahigh pressure crustal rocks during collision of spontaneously moving plates.Journal of Metamorphic Geology, in press availableRussia, KazakhstanKokchetav Massif, UHP
DS201312-0306
2013
Gerya, T.Gerya, T.Precambrian geodynamics: concepts and models.Gondwana Research, Vol. 23, 2, pp. 391-840.MantleGeodynamics - overview
DS201312-0321
2013
Gerya, T.Gorczyk, W., Hobbs, B., Gessner, K., Gerya, T.Intracratonic geodynamics.Gondwana Research, Vol. 24, 3, pp. 838-848.MantleCraton, compression, extension
DS201312-0829
2014
Gerya, T.Sizova, E., Gerya, T., Brown, M.Contrasting styles of Phanerozoic and Precambrian continental collision.Gondwana Research, Vol. 25, 2, pp. 522-545.MantleGeothermometry
DS201412-0283
2014
Gerya, T.Gerya, T.Precambrian geodynamics: concepts and models.Gondwana Research, Vol. 25, pp. 442-463.MantleTectonics, orogeny, cratons
DS201412-0513
2013
Gerya, T.Liao, J., Gerya, T., Wang, Q.Layered structure of the lithospheric mantle changes dynamics of craton extension.Geophysical Research Letters, Vol. 40, 22, pp. 5861-5866.MantleGeophysics - seismics
DS201412-0835
2014
Gerya, T.Sizova, E., Gerya, T., Brown, M.Contrasting styles of Phanerozoic and Precambrian continental collision.Gondwana Research, Vol. 25, pp. 522-545.MantleTectonics, slab breakoff
DS201506-0282
2015
Gerya, T.Koptev, A., Calais, E., Burov, E., Leroy, S., Gerya, T.Dual continental rift systems generated by plume-lithosphere interaction. Central East African RiftNature Geoscience, Vol. 8, pp. 388-392.AfricaMagmatism
DS201602-0187
2015
Gerya, T.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.
DS201605-0835
2016
Gerya, T.Fischer, R., Gerya, T.Early Earth plume-lid tectonics: a high resolution 3D numerical modellling approach.Journal of Geodynamics, in press available 17p.MantleSubduction

Abstract: Geological-geochemical evidence point towards higher mantle potential temperature and a different type of tectonics (global plume-lid tectonics) in the early Earth (>3.2 Ga) compared to the present day (global plate tectonics). In order to investigate tectono-magmatic processes associated with plume-lid tectonics and crustal growth under hotter mantle temperature conditions, we conduct a series of 3D high-resolution magmatic-thermomechanical models with the finite-difference code I3ELVIS. No external plate tectonic forces are applied to isolate 3D effects of various plume-lithosphere and crust-mantle interactions. Results of the numerical experiments show two distinct phases in coupled crust-mantle evolution: (1) a longer (80-100 Myr) and relatively quiet ‘growth phase’ which is marked by growth of crust and lithosphere, followed by (2) a short (?20 Myr) and catastrophic ‘removal phase’, where unstable parts of the crust and mantle lithosphere are removed by eclogitic dripping and later delamination. This modelling suggests that the early Earth plume-lid tectonic regime followed a pattern of episodic growth and removal also called episodic overturn with a periodicity of ?100 Myr.
DS201609-1717
2016
Gerya, T.Fischer, R., Gerya, T.Regimes of subduction and lithospheric dynamics in the Precambrian: 3D thermomechanical modelling.Gondwana Research, Vol. 37, pp. 53-70.MantlePlate Tectonics

Abstract: Comparing the early Earth to the present day, geological-geochemical evidence points towards higher mantle potential temperature and a different type of tectonics. In order to investigate possible changes in Precambrian tectonic styles, we conduct 3D high-resolution petrological-thermomechanical numerical modelling experiments for oceanic plate subduction under an active continental margin at a wide range of mantle potential temperature TP (? TP = 0 ? 250 K, compared to present day conditions). At present day mantle temperatures (? TP = 0 K), results of numerical experiments correspond to modern-style subduction, whereas at higher temperature conditions important systematic changes in the styles of both lithospheric deformation and mantle convection occur. For ? TP = 50 ? 100 K a regime of dripping subduction emerges which is still very similar to present day subduction but is characterised by frequent dripping from the slab tip and a loss of coherence of the slab, which suggests a close relationship between dripping subduction and episodic subduction. At further increasing ? TP = 150 ? 200 K dripping subduction is observed together with unstable dripping lithosphere, which corresponds to a transitional regime. For ? TP = 250 K, presumably equivalent to early Archean, the dominating tectonic style is characterised by small-scale mantle convection, unstable dripping lithosphere, thick basaltic crust and small plates. Even though the initial setup is still defined by present day subduction, this final regime shows many characteristics of plume-lid tectonics. Transition between the two end-members, plume-lid tectonics and plate tectonics, happens gradually and at intermediate temperatures elements of both tectonic regimes are present. We conclude, therefore, that most likely no abrupt geodynamic regime transition point can be specified in the Earth's history and its global geodynamic regime gradually evolved over time from plume-lid tectonics into modern style plate tectonics.
DS201706-1102
2017
Gerya, T.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.
DS201710-2221
2017
Gerya, T.Chowdbury, P., Gerya, T., Chakraborty, S.Emergence of silicic continents as the lower crust peels off on a hot plate tectonic Earth.Nature Geoscience, Vol. 10, 9, pp. 698-703.Mantleplumes

Abstract: The rock record and geochemical evidence indicate that continental recycling has been occurring since the early history of the Earth. The stabilization of felsic continents in place of Earth’s early mafic crust about 3.0 to 2.0 billion years ago, perhaps due to the initiation of plate tectonics, implies widespread destruction of mafic crust during this time interval. However, the physical mechanisms of such intense recycling on a hotter, (late) Archaean and presumably plate-tectonic Earth remain largely unknown. Here we use thermomechanical modelling to show that extensive recycling via lower crustal peeling-off (delamination but not eclogitic dripping) during continent-continent convergence was near ubiquitous during the late Archaean to early Proterozoic. We propose that such destruction of the early mafic crust, together with felsic magmatism, may have caused both the emergence of silicic continents and their subsequent isostatic rise, possibly above the sea level. Such changes in the continental character have been proposed to influence the Great Oxidation Event and, therefore, peeling-off plate tectonics could be the geodynamic trigger for this event. A transition to the slab break-off controlled syn-orogenic recycling occurred as the Earth aged and cooled, leading to reduced recycling and enhanced preservation of the continental crust of present-day composition.
DS201801-0036
2017
Gerya, T.Malierova, P., Schulmann, K., Gerya, T.Relamination styles in collisional orogens.Tectonics, in press availableMantlesubduction

Abstract: During continental collision, a part of the lower-plate material can be subducted, emplaced at the base of the upper plate, and eventually incorporated into its crust. This mechanism of continental-crust transformation is called relamination and it has been invoked to explain occurrences of high-pressure felsic rocks in different structural positions of several orogenic systems. In the present study we reproduced relamination during continental collision in a thermo-mechanical numerical model. We performed a parametric study and distinguished three main types of evolution regarding the fate of the subducted continental crust: (i) return along the plate interface in a subduction channel or wedge, (ii) flow at the bottom of the upper-plate lithosphere and subsequent trans-lithospheric exhumation near the arc or in the back-arc region ("sub-lithospheric relamination"), and (iii) nearly horizontal flow directly into the upper-plate crust ("intra-crustal relamination"). Sub-lithospheric relamination is preferred for relatively quick convergence of thin continental plates. An important factor for the development of sub-lithospheric relamination is melting of the subducted material, which weakens the lithosphere and opens a path for the exhumation of the relaminant. In contrast, a thick and strong overriding plate typically leads to exhumation near the plate interface. If the overriding plate is too thin or weak, intra-crustal relamination occurs. We show that each of these evolution types has its counterpart in nature: (i) the Alps and the Caledonides, (ii) the Himalayan-Tibetan system and the European Variscides, and (iii) pre-Cambrian ultra-hot orogens.
DS201801-0069
2017
Gerya, T.Stern, R.J., Gerya, T.Subduction initiation in nature and models: a review.Tectonophysics, in press available, 26p.Mantlesubduction

Abstract: How new subduction zones form is an emerging field of scientific research with important implications for our understanding of lithospheric strength, the driving force of plate tectonics, and Earth's tectonic history. We are making good progress towards understanding how new subduction zones form by combining field studies to identify candidates and reconstruct their timing and magmatic evolution and undertaking numerical modeling (informed by rheological constraints) to test hypotheses. Here, we review the state of the art by combining and comparing results coming from natural observations and numerical models of SI. Two modes of subduction initiation (SI) can be identified in both nature and models, spontaneous and induced. Induced SI occurs when pre-existing plate convergence causes a new subduction zone to form whereas spontaneous SI occurs without pre-existing plate motion when large lateral density contrasts occur across profound lithospheric weaknesses of various origin. We have good natural examples of 3 modes of subduction initiation, one type by induced nucleation of a subduction zone (polarity reversal) and two types of spontaneous nucleation of a subduction zone (transform collapse and plumehead margin collapse). In contrast, two proposed types of subduction initiation are not well supported by natural observations: (induced) transference and (spontaneous) passive margin collapse. Further work is therefore needed to expand on and understand the implications of these observations. Our future advancing understanding of SI will come from better geologic insights, laboratory experiments, and numerical modeling, and with improving communications between these communities.
DS201804-0713
2017
Gerya, T.Koptev, A., Cloetingh, S., Gerya, T., Calais, E., Leroy, S.Non-uniform splitting of a single mantle plume by double cratonic roots: insights into the origin of the central and southern East African Rift System.Terra Nova, pp. 125-134.Africa, Tanzaniacraton

Abstract: Using numerical thermo?mechanical experiments we analyse the role of an active mantle plume and pre?existing lithospheric thickness differences in the structural development of the central and southern East African Rift system. The plume?lithosphere interaction model setup captures the essential features of the studied area: two cratonic bodies embedded into surrounding lithosphere of normal thickness. The results of the numerical experiments suggest that localization of rift branches in the crust is mainly defined by the initial position of the mantle plume relative to the cratons. We demonstrate that development of the Eastern branch, the Western branch and the Malawi rift can be the result of non?uniform splitting of the Kenyan plume, which has been rising underneath the southern part of the Tanzanian craton. Major features associated with Cenozoic rifting can thus be reproduced in a relatively simple model of the interaction between a single mantle plume and pre?stressed continental lithosphere with double cratonic roots.
DS201905-1051
2019
Gerya, T.Koptev, A., Beniest, A., Gerya, T., Ehlers, T.A., Jolivet, L., Leroy, S.Plume induced breakup of a subducting plate: microcontinent formation without cessation of the subduction process.Geophysical Research Letters, Vol. 46, 7, pp. 3663-3675.Mantlesubduction

Abstract: Separation of microcontinental blocks from their parent continent is usually attributed to abrupt relocation of concentrated extension from the mid?oceanic ridge to the adjacent continental margin. In the context of extensional passive margin evolution, previous extensive numerical and analog studies have revealed that hot upwelling mantle flow plays a key role in the mechanical weakening of the passive margin lithosphere needed to initiate a ridge jump. This, in turn, results in continental breakup and subsequent microcontinent isolation. However, the consequences of mantle plume impingement on the base of a moving lithospheric plate that is already involved into subduction are still unexplored quantitatively. Here we present the results of 3?D thermo?mechanical models showing that even in the context of induced plate motion (contractional boundary conditions), which are necessary to sustain continuous convergence, thermal and buoyancy effects of the mantle plume emplaced at the bottom of the continental part of the subducting plate are sufficient to initiate continental breakup and the subsequent opening of a new oceanic basin that separates the microcontinental block from the main body of the continent. With these models, we show that it is physically possible to form microcontinents in a convergent setting without the cessation of subduction.
DS201911-2525
2019
Gerya, T.Gerya, T.Geodynamics of the Early Earth: quest for the missing paradigm.Geology, Vol. 47, pp. 1006-1007.Mantlegeodynamics

Abstract: In contrast to modern-day plate tectonics, geodynamics of the early Earth presents a unique challenge, as currently there is no consensus on a global paradigm concerning the mantle dynamics and lithosphere tectonics in the Precambrian (Benn et al., 2006; Gerya, 2014). This challenge is mainly due to the severe objective restrictions of obtaining geological and/or geophysical observations constraining Earth’s surface and interior dynamics back in geological time (Fig. 1). The subject of geodynamics can be schematically represented by the time-depth diagram (see Fig. 1) covering the entire Earth’s history and interior. In theory, the entire diagram should be "covered" by data points characterizing the physical-chemical state of Earth at different depths, for different moments in geological time. However, in practice, observations are only available along two axes: (1) geophysical data for Earth’s internal structure at all ranges of depths, but only for the very short present-day time, and (2) the geological record preserved in rocks formed over a broad range of geological times, but only at a very shallow depth range. As a result, the importance of well-constrained geological and geophysical data, and thoroughly studied present-day geodynamic regime (modern-style plate tectonics) is almost unavoidably exaggerated and "stretched" toward the Precambrian Earth. This "plate tectonics trap" can only be avoided by further calibrating our geological intuition on the basis of numerical geodynamic modeling that integrates available geological, geochemical, petrological, and geochronological records (Gerya, 2014).
DS202108-1270
2021
Gerya, T.Baes, M., Sobolev, S., Gerya, T., Stern, R., Brune, S.Plate motion and plume-induced subduction inititation.Gondwana Research, Vol. 98, pp. 277-288. pdfSouth Americasubduction

Abstract: Impingement of a hot buoyant mantle plume head on the lithosphere is one of the few scenarios that can initiate a new subduction zone without requiring any pre-existing weak zones. This mechanism can start subduction and plate tectonics on a stagnant lid and can also operate during active plate tectonics where plume-lithosphere interactions is likely to be affected by plate motion. In this study, we explore the influence of plate motion on lithospheric response to plume head-lithosphere interaction including the effect of magmatic weakening of lithosphere. Using 3d thermo-mechanical models we show that the arrival of a new plume beneath the lithosphere can either (1) break the lithosphere and initiate subduction, (2) penetrate the lithosphere without subduction initiation, or (3) spread asymmetrically below the lithosphere. Outcomes indicate that lithospheric strength and plume buoyancy control plume penetration through the lithosphere whereas the plate speed has a subordinate influence on this process. However, plate motion may affect the geometry and dynamics of plume-lithosphere interaction by promoting asymmetry in the subduction zone shape. When a sufficiently buoyant plume hits a young but subductable moving lithosphere, a single-slab modern-style subduction zone can form instead of multiple subduction zones predicted by stagnant lid models. In the case of subduction initiation of older moving oceanic lithosphere, asymmetrical cylindrical subduction is promoted instead of more symmetrical stagnant lid subduction. We propose that the eastward motion of the Farallon plate in Late Cretaceous time could have played a key role in forming one-sided subduction along the southern and western margin of the Caribbean and NW South America.
DS1992-1182
1992
Gerya, T.V.Perchuk, L.L., Gerya, T.V.The fluid regime of metamorphism and the charnockite reaction ingranulites: a reviewInternational Geology Review, Vol. 34, No. 1, January pp. 1-58RussiaGranulites -review, metamorphism
DS1996-1108
1996
Gerya, T.V.Perchuk, L.L., Gerya, T.V., Van Reenen, D.D., Safonov, SmitThe Limpopo metamorphic belt, South Africa: decompression and cooling regimes of granulites...Petrology, Vol. 4, No. 6, Nov-Dec. pp. 571-599.South AfricaCraton - Kaapvaal, Limpopo metamorphic belt
DS2000-0754
2000
Gerya, T.V.Perchuk, L.L., Gerya, T.V., Krotov, A.V.P-T paths and tectonic evolution of shear zones separating high grade terrains from cratons:Min. Petrol., Vol. 69, No. 1-2, pp. 109-42.South Africa, Russia, Kola PeninsulaHigh grade terrains - comparison, Tectonics - Kola and Limpopo
DS2000-0755
2000
Gerya, T.V.Perchuk, L.L., Gerya, T.V., Yu.M.Comparative petrology and metamorphic evolution of the Limpopo (South Africa) and Lapland ( Fennoscandia)...Min. Petrol., Vol. 69, No. 1-2, pp. 69-108.South Africa, Scandinavia, LaplandHigh grade terrains - comparison, Petrology, metamorphism
DS2002-0555
2002
Gerya, T.V.Gerya, T.V., Maresch, W.V., Willner, A.P.Lithospheric detachment and slab breakoff under the Variscan collisional orogen: keys to the origin of diamond bearing crustal rocks in the Bohemmian Massif.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.218.Europe, GermanyDiamond - bearing quartzo-feldspathic
DS2002-0556
2002
Gerya, T.V.Gerya, T.V., Perchuk, L.L., Maresch, W.V., Willner, A.P., Van ReenenThermal regime and gravitational instability of multi layered continental crust:European Journal of Mineralogy, Vol. 14,4,pp. 687-700.MantleUHP - not specific to diamonds
DS2003-0460
2003
Gerya, T.V.Gerya, T.V., Yuen, D.A.Rayleigh Taylor instabilities from hydration and melting propel 'cold plumes' atEarth and Planetary Science Letters, Vol. 212, 1-2, pp. 47-62.MantleBlank
DS200412-0106
2003
Gerya, T.V.Barton, J.M., Gerya, T.V.Mylonization and decomposition of garnet: evidence for rapid deformation and entrainment of mantle garnet harzburgite by kimberlSouth African Journal of Geology, Vol. 106, 2-3, pp. 231-246.Africa, South AfricaDeposit - Venetia, garnet mineralogy
DS200412-0653
2003
Gerya, T.V.Gerya, T.V., Uken, R., Reinhardt, J., Watkeys, M.K., Maresch, W.V., Clarke, B.M.Cold fingers in a hot magma: numerical modeling of country rock diapirs in the Bushveld Complex, South Africa.Geology, Vol. 31, 9, pp. 753-6.Africa, South AfricaDiapirism, magmatism, plumes, subduction zones
DS200412-0654
2003
Gerya, T.V.Gerya, T.V., Yuen, D.A.Rayleigh Taylor instabilities from hydration and melting propel 'cold plumes' at subduction zones.Earth and Planetary Science Letters, Vol. 212, 1-2, pp. 47-62.MantleMelting, plumes
DS200512-0839
2005
Gerya, T.V.Perchuk, A.L., Gerya, T.V.Subsidence and exhumation dynamics of eclogites in the Yukon-Tanana Terrane, Canadian Cordillera: petrological reconstructions and geodynamic modeling.Petrology, Vol. 13, 3, pp. 253-266.Canada, YukonEclogite
DS200612-0450
2006
Gerya, T.V.Gerya, T.V.Deep continental crust subduction during incipient orogeny: metamorphic and magmatic consequences.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 14, abstract only.MantleSubduction
DS200612-0451
2006
Gerya, T.V.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
Gerya, T.V.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
Gerya, T.V.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
DS200712-0374
2007
Gerya, T.V.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
DS200812-0187
2008
Gerya, T.V.Castro, A., Gerya, T.V.Magmatic implications of mantle wedge plumes: experimental study.Lithos, Vol. 103, 1-2, pp. 138-148.MantlePlume, magmatism
DS200812-0399
2008
Gerya, T.V.Gerya, T.V., Connolly, J.A.D., Yuen, D.A.Why is terrestrial subduction one-sided?Geology, Vol. 36, 1, pp. 43-46.MantleSubduction, slab dehydration
DS200912-0438
2009
Gerya, T.V.Li, Z., Gerya, T.V.Polyphase formation and exhumation of high to ultrahigh pressure rocks in continental subduction zones: numerical modeling and application to the Sulu ultrahigh pressure terrane in eastern China.Journal of Geophysical Research, Vol. 114. B9, B09406ChinaSubduction - UHP
DS200912-0536
2009
Gerya, T.V.Nikolaeva, K.M., Gerya, T.V., Bourdon, B.Subduction dynamics and magmatic arc growth: numerical modeling of isotopic features.Goldschmidt Conference 2009, p. A944 Abstract.MantleSubduction
DS201012-0233
2010
Gerya, T.V.Gerya, T.V., Meilick, F.I.Geodynamic regimes of subduction under an active margin: effects of rheological weakening by fluids and melts.Journal of Metamorphic Geology, In press available,MantleSubduction
DS201012-0439
2010
Gerya, T.V.Li, H., Gerya, T.V., Burg, J.P.Influence of tectonic overpressure on P-T paths of HP-UHP rocks in continental collision zones: thermomechanical modeling.Journal of Metamorphic Geology, Vol. 28, 3, pp. 227-247.MantleUHP
DS201112-0362
2011
Gerya, T.V.Gerya, T.V., Meilick, F.I.Geodynamic regimes of subduction under an active margin: effects of rheological weakening of fluids and melts.Journal of Metamorphic Geology, Vol. 29, 1, pp. 7-31.MantleMelting
DS201112-0600
2011
Gerya, T.V.Li, Z.H., Xu, Z.Q., Gerya, T.V.Flat versus steep subduction: constrasting modes for the formation and exhumation of high to ultrahigh pressure rocks in continental collision zones.Earth and Planetary Science Letters, Vol. 301, 1-2, pp. 65-77.MantleSubduction
DS201212-0173
2012
Gerya, T.V.Duretz, T., Gerya, T.V., Kaus, B.J.P., Andersen, T.B.Thermomechanical modeling of slab eduction.Journal of Geophysical Research, Vol. 117, B08411 17p.MantlePlate tectonics - subduction
DS201212-0174
2012
Gerya, T.V.Duretz, T., Schmalholz, S.M., Gerya, T.V.Dynamics of slab detachment.Geochemical, Geophysics, Geosystems: G3, Vol. 13, 3, 17p.MantleBreakoff, heating
DS201312-0231
2013
Gerya, T.V.Duretz, T., Gerya, T.V.Slab detachment during continental collision: influence of crustal rheology and interaction with lithospheric delamination.Tectonophysics, Vol. 602, pp. 124-140.MantleRheology
DS201312-0348
2013
Gerya, T.V.Hacker, B.R., Gerya, T.V.Paradigms, new and old, for ultrahigh-pressure tectonism.Tectonophysics, Vol. 603, pp. 79-88.MantleUHP
DS201312-0349
2013
Gerya, T.V.Hacker, B.R., Gerya, T.V., Gilotti, J.Formation and exhumation of ultrahigh pressure terranes.Elements, Vol. 9, 4, pp. 289-293.MantleUHP
DS201412-0954
2014
Gerya, T.V.Vogt, K., Gerya, T.V.From oceanic plateaus to allochthonous terranes: numerical modelling.Gondwana Research, Vol. 25, pp. 494-508.MantleSubduction
DS201609-1719
2016
Gerya, T.V.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).
DS201612-2302
2016
Gerya, T.V.Huangfu, P., Wang, Y., Cawood, P.A., Li, Z-H., Fan, W., Gerya, T.V.Thermo-mechanical controls of flat subduction: insight from numerical modeling.Gondwana Research, Vol. 40, pp. 170-183.MantleSubduction

Abstract: Numerical experiments are used to investigate the thermo-mechanical controls for inducing flat subduction and why flat subduction is rare relative to normal/steep subduction. Our modeling results demonstrate that flat subduction is an end-member of a steady state subduction geometry and is characterized by a curved slab with a nearly-horizontal slab section. Intermediate cases between normal/steep and flat subduction appear to be transient in origin and evolve toward one of the stable end-members. Physical parameters inducing flat subduction can be classified into four categories: buoyancy of the subducting oceanic lithosphere (e.g., slab age, oceanic crustal thickness), viscous coupling between the overriding and downgoing plates (e.g., initial subduction angle), external kinematic conditions, and rheological properties of the subduction zone. On the basis of parameter sensitivity tests and the main characteristics of present-day flat subduction zones, positive buoyancy from either the young slab or the thickened oceanic crust is considered as the primary controlling parameter. Our results show that the possibility of flat subduction is directly proportional to oceanic crustal thickness and inversely proportional to the slab age. Furthermore, oceanic crust must be thicker than 8 km to induce flat subduction, when the slab is older than 30 Ma with an initial subduction angle of ? 20° and without absolute trenchward motion of the overriding plate. The lower the initial subduction angle or the thicker the overriding continental lithosphere, the more likelihood for flat subduction. The initial subduction angle is more influential for the development of flat subduction than the overriding lithospheric thickness, and a thick overriding lithosphere induces flat subduction only under the condition of an initial subduction angle of ? 25°, with a slab age of ? 30 Ma and without absolute trenchward motion of the overriding plate. However, when the initial subduction angle is increased to > 25°, no flat subduction is predicted. All the parameters are evaluated within the constraints of a mechanical framework in which the slab geometry is regarded as a result of a balance between the gravitational and hydrodynamic torques. Any factor that can sufficiently reduce gravitational torque or increase hydrodynamic torque will exert a strong effect on flat subduction development. Our results are consistent with the observations of modern flat subduction zones on Earth.
DS201707-1356
2016
Gerya, T.V.Perchuk, A.L., Safonov, O.G., Smit, C.A., van Reenen, D.D., Zkharov, V.S., Gerya, T.V.Precambrian ultra hot orogenic factory: making and reworking of continental crust.Tectonophysics, in press availableMantleUHP

Abstract: Mechanisms of Precambrian orogeny and their contribution to the origin of ultrahigh temperature granulites, granite-greenstone terranes and net crustal growth remain debatable. Here, we use 2D numerical models with 150 °C higher mantle temperatures compared to present day conditions to investigate physical and petrological controls of Precambrian orogeny during forced continental plates convergence. Numerical experiments show that convergence between two relatively thin blocks of continental lithosphere with fertile mantle creates a short-lived cold collisional belt that later becomes absorbed by a long-lived thick and flat ultra-hot accretionary orogen with Moho temperatures of 700–1100 °C. The orogen underlain by hot partially molten depleted asthenospheric mantle spreads with plate tectonic rates towards the incoming lithospheric block. The accretionary orogeny is driven by delamination of incoming lithospheric mantle with attached mafic lower crust and invasion of the hot partially molten asthenospheric wedge under the accreted crust. A very fast convective cell forms atop the subducting slab, in which hot asthenospheric mantle rises against the motion of the slab and transports heat towards the moving orogenic front. Juvenile crustal growth during the orogeny is accompanied by net crustal loss due to the lower crust subduction. Stability of an ultra-hot orogeny is critically dependent on the presence of relatively thin and warm continental lithosphere with thin crust and dense fertile mantle roots subjected to plate convergence. Increased thickness of the continental crust and subcontinental lithospheric mantle, pronounced buoyancy of the lithospheric roots, and decreased mantle and continental Moho temperature favor colder and more collision-like orogenic styles with thick crust, reduced magmatic activity, lowered metamorphic temperatures, and decreased degree of crustal modification. Our numerical modeling results thus indicate that different types of orogens (cold, mixed-hot and ultra-hot) could be created at the same time in the Early Earth, depending on compositional and thermal structures of interacting continental blocks.
DS201901-0055
2018
Gerya, T.V.Perchuk, A.L., Safonov, O.G., Smit, C.A., van Reenen, D.D., Zakharov, V.S., Gerya, T.V.Precambrian ultra-hot orogenic factory: making and reworking of continental crust.Tectonophysics, Vol. 746, pp. 572-586.Mantlesubduction

Abstract: Mechanisms of Precambrian orogeny and their contribution to the origin of ultrahigh temperature granulites, granite-greenstone terranes and net crustal growth remain debatable. Here, we use 2D numerical models with 150 °C higher mantle temperatures compared to present day conditions to investigate physical and petrological controls of Precambrian orogeny during forced continental plates convergence. Numerical experiments show that convergence between two relatively thin blocks of continental lithosphere with fertile mantle creates a short-lived cold collisional belt that later becomes absorbed by a long-lived thick and flat ultra-hot accretionary orogen with Moho temperatures of 700-1100 °C. The orogen underlain by hot partially molten depleted asthenospheric mantle spreads with plate tectonic rates towards the incoming lithospheric block. The accretionary orogeny is driven by delamination of incoming lithospheric mantle with attached mafic lower crust and invasion of the hot partially molten asthenospheric wedge under the accreted crust. A very fast convective cell forms atop the subducting slab, in which hot asthenospheric mantle rises against the motion of the slab and transports heat towards the moving orogenic front. Juvenile crustal growth during the orogeny is accompanied by net crustal loss due to the lower crust subduction. Stability of an ultra-hot orogeny is critically dependent on the presence of relatively thin and warm continental lithosphere with thin crust and dense fertile mantle roots subjected to plate convergence. Increased thickness of the continental crust and subcontinental lithospheric mantle, pronounced buoyancy of the lithospheric roots, and decreased mantle and continental Moho temperature favor colder and more collision-like orogenic styles with thick crust, reduced magmatic activity, lowered metamorphic temperatures, and decreased degree of crustal modification. Our numerical modeling results thus indicate that different types of orogens (cold, mixed-hot and ultra-hot) could be created at the same time in the Early Earth, depending on compositional and thermal structures of interacting continental blocks.
DS201906-1333
2019
Gerya, T.V.Perchuk, A.L., Zakharov, V.S., Gerya, T.V., Brown, M.Hotter mantle but colder subduction in the Precambrian: what are the implications?Precambrian Research, Vol. 330, pp. 20-34.Mantlesubduction

Abstract: On contemporary Earth, subduction recycles mafic oceanic crust and associated volatile elements, creating new silicic continental crust in volcanic arcs. However, if the mantle was hotter in the Precambrian, the style of subduction, the depth of devolatilization and the formation of silicic continental crust may have been different. Consequently, the generation of the tonalite-trondhjemite-granodiorite (TTG) suite, which is characteristic of Archean crust, may not have been related to subduction. Here, we use a two-dimensional numerical magmatic-thermomechanical model to investigate intraoceanic subduction for contemporary mantle conditions and at higher mantle temperatures, as appropriate to the Precambrian. In each case, we characterize the thermal structure of the subducting plate and investigate magma compositions and production rates. We use these results to assess the potential growth of silicic continental crust associated with intraoceanic subduction at different mantle temperatures. For the Precambrian, in a set of experiments with ?T?=?150?K and decreasing subducting plate velocity, we find that the contemporary style of subduction was preceded by an arc-free regime dominated by rapid trench rollback and vigorous upwelling of asthenospheric mantle into the space created above the retreating slab. In this regime, formation of magmas by fluid-fluxed melting of the mantle is suppressed. Instead, decompression melting of upwelling asthenospheric mantle results in the widespread development of voluminous plateau-like basaltic magmas. In addition, retreating subduction at higher mantle temperature causes faster descent of the downgoing slab, leads to colder thermal gradients, similar to those associated with active subduction in the western Pacific today, and suppresses melting of the basaltic crust, limiting production of silicic (adakite-like) magmas. With increasing maturity of the subduction system, retreat of the subducting plate ceases, the role of decompression melting strongly decreases and fluid-fluxed melting of the mantle coupled with melting of the hydrated slab begins to produce basaltic and felsic arc volcanic rocks similar to those formed during contemporary subduction. In an additional series of individual experiments at various ?T, an increase of the mantle temperature above ?T?=?150?K leads to episodic and short-lived subduction accompanied by limited production of silicic continental crust. The results of our experimental study demonstrate that a hotter mantle in the Precambrian changes dramatically both the slab dynamics and the processes of magma generation and crustal growth associated with intraoceanic subduction zones. These changes may preclude growth of the early Precambrian silicic continental crust by processes that were dominantly similar to those associated with contemporary subduction.
DS201908-1780
2019
Gerya, T.V.Jain, C., Rozel, A.B., Tackley, P.J., Sanan, P., Gerya, T.V.Growing primordial continental crust self-consistently in global mantle convection models.Gondwana Research, Vol. 73, pp. 96-122.Mantlegeothermometry

Abstract: The majority of continental crust formed during the hotter Archean was composed of Tonalite-Trondhjemite-Granodiorite (TTG) rocks. In contrast to the present-day loci of crust formation around subduction zones and intra-plate tectonic settings, TTGs are formed when hydrated basalt melts at garnet-amphibolite, granulite or eclogite facies conditions. Generating continental crust requires a two step differentiation process. Basaltic magma is extracted from the pyrolytic mantle, is hydrated, and then partially melts to form continental crust. Here, we parameterise the melt production and melt extraction processes and show self-consistent generation of primordial continental crust using evolutionary thermochemical mantle convection models. To study the growth of TTG and the geodynamic regime of early Earth, we systematically vary the ratio of intrusive (plutonic) and eruptive (volcanic) magmatism, initial core temperature, and internal friction coefficient. As the amount of TTG that can be extracted from the basalt (or basalt-to-TTG production efficiency) is not known, we also test two different values in our simulations, thereby limiting TTG mass to 10% or 50% of basalt mass. For simulations with lower basalt-to-TTG production efficiency, the volume of TTG crust produced is in agreement with net crustal growth models but overall crustal (basaltic and TTG) composition stays more mafic than expected from geochemical data. With higher production efficiency, abundant TTG crust is produced, with a production rate far exceeding typical net crustal growth models but the felsic to mafic crustal ratio follows the expected trend. These modelling results indicate that (i) early Earth exhibited a "plutonic squishy lid" or vertical-tectonics geodynamic regime, (ii) present-day slab-driven subduction was not necessary for the production of early continental crust, and (iii) the Archean Earth was dominated by intrusive magmatism as opposed to "heat-pipe" eruptive magmatism.
DS201911-2510
2019
Gerya, T.V.Beaussier, S.J., Gerya, T.V., Burg, J-P.3D numerical modelling of the Wilson cycle: structural inheritance of alternating subduction polarity.N: Cycle Concepts in Plate Tectonics, editors Wilson and Houseman , Geological Society of London special publication 470, 439-461.Mantleplate tectonics

Abstract: Alternating subduction polarity along suture zones has been documented in several orogenic systems. Yet the mechanisms leading to this geometric inversion and the subsequent interplay between the contra-dipping slabs have been little studied. To explore such mechanisms, 3D numerical modelling of the Wilson cycle was conducted from continental rifting, breakup and oceanic spreading to convergence and self-consistent subduction initiation. In the resulting models, near-ridge subduction initiating with the formation of contra-dipping slab segments is an intrinsically 3D process controlled by earlier convergence-induced ridge swelling. The width of the slab segments is delimited by transform faults inherited from the rifting and ocean floor spreading stages. The models show that the number of contra-dipping slab segments depends mainly on the size of the oceanic basin, the asymmetry of the ridge and variations in kinematic inversion from divergence to convergence. Convergence velocity has been identified as a second-order parameter. The geometry of the linking zone between contra-dipping slab segments varies between two end-members governed by the lateral coupling between the adjacent slab segments: (1) coupled slabs generate wide, arcuate linking zones holding two-sided subduction; and (2) decoupled slabs generate narrow transform fault zones against which one-sided, contra-dipping slabs abut.
DS202202-0227
2022
Gerya, T.V.Zakharov, V.S., Lubina, N.V., Stepanova, A.V., Gerya, T.V.Simultaneous intruding of mafic and felsic magmas into the extending continental crust caused by mantle plume underplating: 2D magmatic-thermomechanical modeling and implications for the Paleoproterozoic Karelian cratonTectonophysics, Vol. 822, 229173, 13p. PdfEuropemagmatism

Abstract: Available data suggest that the breakup of the Neoarchean Kenorland supercontinent at 2.5-2.4 Ga was likely triggered by a large mantle plume upwelling that caused significant magmatism. Here, we present 2D high-resolution magmatic-thermomechanical numerical models of extension of the continental crust underplated by a hot mantle plume material. Using this model, it is demonstrated that mantle plume underplating generates a large amount of mafic melt by decompression melting. This melt penetrates into the extending continental crust along normal faults thereby forming multiple generations of mafic dyke-like intrusions along normal faults. In case of extension velocity of 0.2-1 cm/yr, lower crustal heating and hot mafic melt emplacement may cause partial melting of the continental crust that can generate significant volume of felsic melts. This in turn triggers emplacement of felsic intrusions that temporarily and spatially associate with the mafic dyke-like intrusions. The modeling results agree well with geological data from the Karelian Craton and provide possible explanation for the observed association of Paleoproterozoic mafic dykes and felsic intrusions which formed in a relatively short time interval (up to 20 Myrs) in the early stages of the supercontinent breakup.
DS2002-0557
2002
GESCAD Inc.GESCAD Inc.Map of region of Wemindji. email [email protected]Gescad Inc., Sept. 1:200,000 approx. 100.00 a map sheetQuebecMap - ad
DS1960-0951
1968
Geschal. ZeitungGeschal. ZeitungEin Guter FundDeutsch. Geschal. Zeitung, No. 8, P. 815.RussiaDiamond Occurrence
DS2002-0558
2002
Gesicki, A.L.D.Gesicki, A.L.D., Riccomini, C., Boggiani, P.C.Ice flow direction during late Paleozoic glaciation in western Parana Basin, BrasilJournal of South American Earth Sciences, Vol.14, 8, March pp. 933-9.BrazilGeomorphology
DS1988-0569
1988
Gesing, R.Richardson, P.R., Gesing, R.Prospects for minerals in the 90's. Eighteenth CRS PolicyDiscussionSeminarCentre for Resource Studies, 131pCanadaEconomics, Book -Table of contents
DS2002-0559
2002
Gessman, C.K.Gessman, C.K., Wood, B.J.Potassium in the Earth's coreEarth and Planetary Science Letters, Vol. 200, No. 1-2, pp. 63-78.MantleGeochemistry
DS2001-0379
2001
Gessmannl, C.K.Gessmannl, C.K., Wood, B.J., Kilburn, M.R.Solubility of silicon in liquid metal at high pressure: implications for the composition of the Earth's core.Earth and Planetary Science Letters, Vol. 184, No. 2, Jan. 15, pp. 367-76.MantleChemistry
DS201312-0321
2013
Gessner, K.Gorczyk, W., Hobbs, B., Gessner, K., Gerya, T.Intracratonic geodynamics.Gondwana Research, Vol. 24, 3, pp. 838-848.MantleCraton, compression, extension
DS202001-0040
2019
Gessner, K.Smithies, R.H., Lu, Y., Johnson, T.E., Kirkland, C.L., Cassidy, K.F., Champion, D.C., Mole, D.R., Zibra, I., Gessner, K., Sapkota, J., De Paoli, M.C., Poujol, M.No evidence for high pressure melting of Earth's crust in the Archean.Nature Communicatons, Vol. 10, 555912p. PdfAustraliamelting

Abstract: Much of the present-day volume of Earth’s continental crust had formed by the end of the Archean Eon, 2.5 billion years ago, through the conversion of basaltic (mafic) crust into sodic granite of tonalite, trondhjemite and granodiorite (TTG) composition. Distinctive chemical signatures in a small proportion of these rocks, the so-called high-pressure TTG, are interpreted to indicate partial melting of hydrated crust at pressures above 1.5?GPa (>50?km depth), pressures typically not reached in post-Archean continental crust. These interpretations significantly influence views on early crustal evolution and the onset of plate tectonics. Here we show that high-pressure TTG did not form through melting of crust, but through fractionation of melts derived from metasomatically enriched lithospheric mantle. Although the remaining, and dominant, group of Archean TTG did form through melting of hydrated mafic crust, there is no evidence that this occurred at depths significantly greater than the ~40?km average thickness of modern continental crust.
DS202202-0228
2022
Gessner, K.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.
DS200912-0071
2009
GestoBraun, 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
DS201811-2572
2018
get-diamondsget-diamondsThe oval diamond cut - history of polishing technique. Lazare Kaplanget-diamonds.com, Oct. 3p.Globaldiamond polishing
DS2001-0380
2001
GETECHGETECH, University of LeedsSouth American gravity and magnetic dat a packagesGetech Advertisement, South AmericaGravity and magnetic data
DS1988-0254
1988
Getman, A.F.Getman, A.F., Andreev, A.V., Vityuk, V.I.Preparation of diamonds from various carbonaceous materials in the presence of metallic melts.(Russian)Sverkhtverd. Mater., (Russian), No. 6, pp. 6-8GlobalDiamond synthesis
DS200912-0840
2009
Getting, I.G.Yoneda, A., Chen, G., Spetzler, H.A., Getting, I.G.The effect of composition, temperature and pressure on the elasticity of olivine and garnet: implications for interpreting seismic velocity variations in mantle.mantleplumes.org, 8p.MantleGeophysics - seismics
DS1991-1092
1991
Gettings, M.E.McCartan, L., Gettings, M.E.Possible relationship between seismicity and warm intrusive bodies in theCharleston, South Carolina, and New Madrid Missouri areasUnited States Geological Survey (USGS) Bulletin, No. 1953, 18pGlobalGeophysics -seismics, Intrusions
DS1993-0188
1993
Gettings, M.E.Bultman, M.W., Force, E.R., Gettings, M.E., Fisher, F.S.Comments on the three step method for quantification of undiscovered mineral resourcesUnited States Geological Survey (USGS) Open File, No. 93-0023, 59p. approx. $ 9.75GlobalEconomics, Resources
DS1991-1541
1991
Getty, S.Selverstone, J., Getty, S., Franz, G., Thomas, S.Fluid heterogeneities and vein formation in 2 GPa eclogites: Implications for the scale of fluid migration during subductionGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 360AustriaEclogites, Subduction
DS2002-0933
2002
Getzmeier, A.Leibecker, J., Getzmeier, A., Honig, M., Kuras, O., Soyer, W.Evidence of electrical anisotropic structures in the lower crust and the upper mantleEarth and Planetary Science Letters, Vol. 202, 2, pp. 289-302.EuropeGeophysics - seismics
DS1950-0499
1959
Geul, J.J.G.Reitan, P.H., Geul, J.J.G.On the Formation of the Carbonate Bearing Ultrabasic Rock At Kviteberg Lyngen, Northern Norway.Norges Geol. Unders. Skr., No. 205, PP. 111-127.Norway, ScandinaviaPetrogenesis
DS200512-0751
2004
GeurtsMoses, 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
DS200912-0380
2008
Geurts, R.H.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
Geurts, R.H.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
DS200612-0453
2005
GeusGeusTikiusaaq - a new carbonatite complex discovered in southern West Greenland.Geus, Greenland News Letter, Minex 28, December p. 4. (1/4p.)Europe, GreenlandCarbonatite
DS1930-0215
1936
Gevers, T.W.Gevers, T.W.Discussion of a Paper by Taljaard " South African Melilite Basalts and Their Relations".Geological Society of South Africa Proceedings, Vol. 39, PP. 93-95.South AfricaMelilitite, Melilite, Related Rocks
DS1960-0049
1960
Gevers, T.W.Gevers, T.W.The Life and Work of Dr. Alex. L. du ToitJohannesburg: Hortors, 109P.South AfricaKimberley, Biography
DS1984-0301
1984
Gevers, T.W.Gevers, T.W.Zur Entdeckungsgeschichte und Herkunft der Diamanten an Derkueste Sudafrikas.Mitteilungen Aus Dem Geologisch Palaeontologischen Institute, No. 56, PP. 13-30.South Africa, Southwest Africa, Namibia, NamaqualandBlank
DS1984-0302
1984
Gevers, T.W.Gevers, T.W.Zur Entdeckungsgeschichte und Herkunft der Diamanten an derKusteSudafrikas.(in German)Mitt. Geol. Palaont. Institute University of Hamburg., (in German), Vol. 56, pp. 13-30Southwest AfricaHistory - Discovery Of Diamonds By Portuguese
DS1975-0427
1976
Gevorkyan, R.G.Veguni, A.T., Gevorkyan, R.G., Palandzhyan, S.A.Certain Geologic Tectonic Hypotheses of the Diamond Bearing capacity of Alpine Type Ultramafics of Armenia.Izd. Vyssh. Uchebn. Zaved. Geol. I Razv., No. 3, PP. 103-106.Russia, ArmeniaGenesis, Kimberlites
DS200812-0400
2008
Geyer, A.Geyer, A., Mart, J.The new worldwide collapse caldera database (CCDB): a tool for studying and understanding caldera processes.Journal of Volcanology and Geothermal Research, Vol. 175, 3. August 10, pp. 334-354.MantleCalderas
DS201112-0363
2011
Geyer, A.Geyer, A., Bindeman, I.Glacial influence on caldera forming eruptions.Journal of Geothermal Volcanology and Research, Vol. 202, 1-2, pp. 127-142.MantleGeomorphology
DS1990-0564
1990
Geyh, M.A.Geyh, M.A., Sclieicher, H.Absolute age determination. Physical and chemical dating methods and theirapplicationSpringer-Verlag book, 503p. approx. $ 70.00 ISBN 3-540-51276-4, GlobalGeochronology, Age determinations
DS1995-1466
1995
Gezaegn, Y.Peccerillo, A., Ferraro, C., Gezaegn, Y.Petrogenesis of peralkaline acid magmas along the main Ethiopian RiftGeological Society Africa 10th. Conference Oct. Nairobi, p. 117. Abstract.GlobalAlkaline rocks, Petrology
DS200812-0345
2008
GezahegnFerrnado, S., Frezzotti, M.L., Neumann, De Astis, Peccerillo, Dereje, Gezahegn, TeklewoldComposition and thermal structure of the lithosphere beneath the Ethiopian plateau: evidence from mantle xenoliths in basanites, Injibara Lake Tana Province.Mineralogy and Petrology, Vol. 93, 1-2, pp. 47-78.Africa, EthiopiaBasanites, Foidites
DS2002-0081
2002
Ghani, A.A.Atherton, M.P., Ghani, A.A.Slab breakoff: a model for Caledonian, Late granite syn-collisional magmatism in the orthotectonic metamorphic zone of Scotland and Donegal, Ireland.Lithos, Vol.62,3-4,pp. 65-85.Scotland, IrelandSubduction - slab
DS200812-0593
2008
Gharibi, M.Korja, T., Smirnov, M., Pdersen, L.B., Gharibi, M.Structure of the Central Scandinavian Caledonides and the underlying Precambrian basement, new constraints from magnetotellurics.Geophysical Journal International, Vol. 175, 1, pp. 55-69.Europe, Sweden, NorwayGeophysics - magnetotellurics
DS1995-1417
1995
Ghashkin, A.I.Palkina, E.Yu., Smirnov, G.I., Ghashkin, A.I., TarasyukTypomorphism of various genetic types of the Ukrainian diamondsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 413-414.UKrainePlacers, alluvials, Diamond morphology
DS201012-0709
2009
Ghassemi, A.Simakin, A.G., Ghassemi, A.The role of magma chamber fault interaction in caldera forming eruptions.Bulletin of Volcanology, Vol. 72, 1, pp. 85-101.MantleMagmatism
DS202004-0523
2020
Ghassemi, A.Kibikas, W.M., Carpenter, B.M., Ghassemi, A.Mechanical strength and physical properties of Oklahoma's igneous basement.Tectonophysics, Vol. 777, 228336, 15p. PdfUnited States, Oklahomageophysics, seismics

Abstract: From 2009 to 2016, a drastic increase in seismic activity occurred in the Central and Eastern US (CEUS), particularly in the Oklahoma-Kansas region. The majority of hypocenters were focused in the crystalline basement rock. Information regarding the physical properties (elastic wave velocity, peak strength, etc.) of rocks in the CEUS basement to date is sparse. Forecasting future seismic hazard and predicting the in situ response of the crystalline basement requires their geomechanical parameters be adequately constrained. This work assesses the mechanical and petrophysical properties of several sets of basement rocks from Oklahoma to provide a better framework for understanding intraplate seismicity and overall basement deformation in the continental United States. Laboratory experiments were conducted with granite, rhyolite and diabase basement rock samples collected from southern Oklahoma. Evolution of compressional and shear wave velocity with increasing confinement was measured through a series of ultrasonic velocity tests. A suite of uniaxial and triaxial tests were conducted to measure the elastic and inelastic deformation behavior of the basement rocks. Deformation data was evaluated using the Mohr-Coulomb criterion and compared with additional preexisting deformation data of igneous basement rocks. Dynamic and static elastic properties compare favorably with available field measurements and demonstrate the role physical properties can play in varying mechanical behavior. Granitic samples demonstrate moderate variation of intrinsic physical properties can alter elastic properties and failure behavior significantly. Water-weakening in the basement rocks may indicate fluid-assisted processes such as stress corrosion cracking enhance deformation in the crystalline basement.
DS201312-0308
2013
Ghatak, A.Ghatak, A., Basu, A.R.Isotopic and trace element geochemistry of alkalic mafic ultramafic carbonatitic complexes and flood basalts in NE India: origin in a heterogeneous Kerguelen plume.Geochimica et Cosmochimica Acta, Vol. 115, pp. 46-72.IndiaCarbonatite
DS201212-0012
2012
Ghattas, O.Alistic, L., Gurnis, M., Stadler, G., Burstedde, C., Ghattas, O.Multi scale dynamics and rheology of mantle flow with plates.Journal of Geophysical Research, Vol. 117, B10 B10402MantleTectonics
DS201312-0113
2013
Ghattas, O.Burstedde, C., Stadler,G., Alisic, L., Wilcox, L.C., Tan, E.,Gurnis, M., Ghattas, O.Large scale adaptive mantle convection simulation.Geophysical Journal International, Vol. 192, no. 3, pp. 889-906.MantleConvection
DS201312-0471
2013
Ghazala, H.Khattach, D., Houan, M.R., Corchete, V., Chourak, M., El Gout, R., Ghazala, H.Main crustal discontinuities of Morocco derived from gravity data.Journal of Geodynamics, Vol. 68, pp. 37-48.Africa, MoroccoTectonics
DS1999-0255
1999
Ghazi, A.M.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
DS200512-1249
2005
Ghazi, A.M.Zhang, S.Q., Mahoney, J.J., Mo, X.X., Ghazi, A.M., Milani, L., Crawford, A.J., Guo, T.Y., Zhao, Z.D.Evidence for a Wide spread Tethyan upper mantle with Indian - Ocean type isotopic characteristics.Journal of Petrology, Vol. 46, 4, pp. 829-858.Indian OceanGeochronology
DS2002-1581
2002
Ghazi, M.Taylor, L.A., Sobolev, N..V., Ghazi, M., Anand, M., Bodner, R.J.The science of diamonds and their inclusions can such dat a be used to establish diamond provenance?Eos, American Geophysical Union, Spring Abstract Volume, Vol.83,19, 1p.BrazilDiamond - inclusions, sulphides
DS2001-0814
2001
Ghebreab, W.Mulugeta, G., Ghebreab, W.Modeling hterogeneous stretching during episodic or steady rifting of the continental lithosphere.Geology, Vol. 29, No. 10, Oct. pp. 895-8.MantleRifting, dynamic modeling
DS201801-0015
2018
Ghelichkhan, S.Friedrich, A.M., Bunge, H-P., Rieger, S.M., Ghelichkhan, S., Nerlich, R.Stratigraphic framework for the plume mode of mantle convection and the analysis of inter regional unconformities on geological maps.Gondwana Research, Vol. 53, 1, pp. 159-188.Mantleconvection

Abstract: Mantle convection is a fundamental planetary process. Its plate mode is established and expressed by plate tectonics. Its plume mode also is established and expressed by interregional geological patterns. We developed both an event-based stratigraphic framework to illustrate the surface effects predicted by the plume model of Griffiths et al. (1989) and Griffiths and Campbell (1990) and a methodology to analyze continent-scale geological maps based on unconformities and hiatuses. The surface expression of ascending plumes lasts for tens-of-millions-of-years and rates vary over a few million years. As the plume ascends, its surface expression narrows, but increases in amplitude, leaving distinct geological and stratigraphic patterns in the geologic record, not only above the plume-head center, but also above its margins and in distal regions a few thousands-of-kilometers from the center. To visualize these patterns, we constructed sequential geological maps, chronostratigraphic sections, and hiatus diagrams. Dome-uplift with erosion (?engör, 2001) and the flood basalts (Duncan and Richards, 1991; Ernst and Buchan, 2001a) are diagnostic starting points for plume-stratigraphic analyses. Mechanical collapse of the dome results in narrow rifting (Burke and Dewey, 1973), drainage-network reorganization (Cox, 1989), and flood-basalt eruption. In the marginal region, patterns of vertical movement, deformation and surface response are transient and complex. At first, the plume margin is uplifted together with the central region, but then it subsides as the plume ascents farther; With plume-head flattening, the plume margin experiences renewed outward-migrating surface uplift, erosion, broad crustal faulting, and drainage reorganization. Knickpoint migration occurs first inward-directed at ½ the rate of plume ascent and later outward-directed at the rate of asthenospheric flow. Interregional-scale unconformity-bounded stratigraphic successions document the two inversions. The distal regions, which did not experience any plume-related uplift, yield complete sedimentary records of the event; Event-related time gaps (hiatuses) in the sedimentary record increase towards the center, but the event horizon is best preserved in the distal region; it may be recognized by tracing its contacts from the center outwards. We extracted system- and series-hiatuses from interregional geological maps and built hiatus maps as proxies for paleo-dynamic topography and as a basis for comparison with results from numerical models. Interregional-scale geological maps are well suited to visualize plume-related geological records of dynamic topography in continental regions. However, geological records and hiatus information at the resolution of stages will be needed at interregional scales. The plume-stratigraphic framework is event-based, interregional, but not global, with time-dependent amplitudes that are significantly larger than those of global eustatic sea-level fluctuations. Global stratigraphic syntheses require integration of plate- and plume-stratigraphic frameworks before eustatic contributions may be assessed.
DS202008-1400
2020
Ghelichkhan, S.Hoggard, M.J., Czarnota, K., Richards, F.D., Huston, D.L., Jaques, A.L., Ghelichkhan, S.Global distribution of sediment hosted metals controlled by craton edge stability. ( not specific to diamonds but of interest)Nature Geoscience, Vol. 13, pp. 504-510.Mantlelithospheric thickness

Abstract: Sustainable development and the transition to a clean-energy economy drives ever-increasing demand for base metals, substantially outstripping the discovery rate of new deposits and necessitating dramatic improvements in exploration success. Rifting of the continents has formed widespread sedimentary basins, some of which contain large quantities of copper, lead and zinc. Despite over a century of research, the geological structure responsible for the spatial distribution of such fertile regions remains enigmatic. Here, we use statistical tests to compare deposit locations with new maps of lithospheric thickness, which outline the base of tectonic plates. We find that 85% of sediment-hosted base metals, including all giant deposits (>10?megatonnes of metal), occur within 200?kilometres of the transition between thick and thin lithosphere. Rifting in this setting produces greater subsidence and lower basal heat flow, enlarging the depth extent of hydrothermal circulation available for forming giant deposits. Given that mineralization ages span the past two?billion?years, this observation implies long-term lithospheric edge stability and a genetic link between deep Earth processes and near-surface hydrothermal mineral systems. This discovery provides an unprecedented global framework for identifying fertile regions for targeted mineral exploration, reducing the search space for new deposits by two-thirds on this lithospheric thickness criterion alone.
DS1970-0691
1973
Ghent, E.D.Ghent, E.D., Coleman, R.G.Eclogites from Southwestern OregonGeological Society of America (GSA) Bulletin., Vol. 84, No. 8, PP. 2471-2488.United States, California, West CoastBlank
DS1970-0692
1973
Ghent, E.D.Ghent, E.D., Peterman, Z.E., Coleman, R.G.Sr 87/ Sr 86, Potassium, Sodium, Rubidium, and Strontium in SOME ECLOGITES and ASSOCIATED BASALTS from CALIFORNIA and SOUTHWESTERN OREGON.United States Geological Survey (USGS) Journal of RES., Vol. 1, No. 6, PP. 643-647.United States, California, Oregon, West CoastEclogites, Basalts, Strontium
DS1994-0614
1994
Ghent, E.D.Ghent, E.D., Stout, M.Z.Geobarometry of low temperature eclogites: applications of isothermal pressure-activity calculations.Contributions to Mineralogy and Petrology, Vol. 116, pp. 500-507.New CaledoniaGeobarometry, Eclogites
DS1998-0395
1998
Ghent, E.D.Erdmer, P., Ghent, E.D., Archibald, D.A., Stout, M.Z.Paleozoic and Mesozoic high pressure metamorphism at the margin of ancestral North America in central YukonGeological Society of America (GSA) Bulletin., Vol. 110, No. 5, May pp. 615-629.Yukonhigh pressure metamorphism, Eclogites
DS2002-0560
2002
Ghent, E.D.Ghent, E.D., Dipple, G.M., Russell, J.K.Modelling the thermodynamic phase relationships and geophysical properties of eclogitic mantle lithosphere.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.239.Northwest TerritoriesEclogite - mineralogy, Deposit - Jericho
DS200412-0655
2004
Ghent, E.D.Ghent, E.D., Dipple, G.M., Russell, J.K.Thermodynamic models for eclogite mantle lithosphere.Earth and Planetary Science Letters, Vol. 218, 3-4, Feb 15, pp. 451-462.Canada, Northwest TerritoriesSlave Craton, Geothermometry, geophysics - seismics
DS202002-0188
2019
Ghent, E.D.Ghent, E.D., Edwards, B.R., Russell, J.K.Pargasite bearing vein in spinel lherzolite from the mantle lithosphere of the North American Cordillera. Canadian Journal of Earth Sciences, Vol. 56, pp. 870-885.Canada, British Columbialherzolite

Abstract: Basanite lavas near Craven Lake, British Columbia, host a spinel lherzolite xenolith containing cross-cutting veins with pargasitic amphibole (plus minor apatite). The occurrence of vein amphibole in spinel lherzolite is singular for the Canadian Cordillera. The vein crosscuts foliated peridotite and is itself cut by the basanite host. The amphibole is pargasite, which is the most common amphibole composition in mantle peridotite. Rare earth element concentrations in the pargasite are similar to those for mafic alkaline rocks across the northern Cordilleran volcanic province (light rare earth elements ?50× chondrite and heavy rare earth elements ?5× chondrite). Two-pyroxene geothermometry suggests that the vein and host peridotite were thermally equilibrated prior to sampling by the basanite magma. Calculated temperature conditions for the sample, assuming equilibration along a model steady-state geotherm, are between 990 and 1050 °C and correspond to a pressure of 0.15 GPa (?52 ± 2 km depth). These conditions are consistent with the stability limits of mantle pargasite in the presence of a fluid having XH2O < ?0.1. The pargasite vein and associated apatite provide direct evidence for postaccretion fracture infiltration of CO2-F-H2O-bearing silicate fluids into the Cordilleran mantle lithosphere. Pargasite with low aH2O is in equilibrium with parts per million concentrations of H2O in mantle olivine, potentially lowering the mechanical strength of the lithospheric mantle underlying the Cordillera and making it more susceptible to processes such as lithospheric delamination. Remelting of Cordilleran mantle lithosphere containing amphibole veins may be involved in the formation of sporadic nephelinite found in the Canadian Cordillera.
DS201902-0297
2019
Ghent, R.R.Mazourel, S., Ghent, R.R., Bottke, W.F., Parker, A.H., Gernon, T.M.Earth and Moon impact flux increased at the end of the Paleozoic. Craters almost abscent older than 650 mln years. Kimberlite ages used.Science, Vol. 363, 6424, Jan. 18, pp. 253-257.Globalgeochronology
DS201908-1798
2019
Ghent, R.R.Mzrouei, S., Ghent, R.R., Bottke, W.F., Parker, A.H., Gernon, T.M.Response to comment on "Earth and Moon impact flux increased at the end of the Paleozoic".Science, Vol. 365, 6450, 8p. eaaw9895 July 19MantleCraton

Abstract: Hergarten et al. interpret our results in terms of erosion and uncertain calibration, rather than requiring an increase in impact flux. Geologic constraints indicate low long-term erosion rates on stable cratons where most craters with diameters of ?20 kilometers occur. We statistically test their proposed recalibration of the lunar crater ages and find that it is disfavored relative to our original calibration.
DS200812-0401
2008
Gheorghe, C.Gheorghe, C.Blood diamonds and the Kimberley Process - five years later. Motherhood outline.Mining.com, September issue pp. 35-37.GlobalNews item - KP
DS202108-1308
2021
Gherardi, M.Rey, T., Leone, F., Defossez, S., Gherardi, M., Parat, F.Volcanic hazards assessment of Oldoinyo Lengai in a data scarcity context.Territorium, Vol. 28, (II) pp. 69-81. pdfAfrica, Tanzaniadeposit - Oldoinyo Lengai

Abstract: The objective of our study is to establish an assessment of four volcanic hazards in a country threatened by the eruption of the OlDoinyo Lengai volcano. The last major eruption dates back to 2007-2008 but stronger activity in 2019 has revived the memory of volcanic threats to the Maasai and Bantu communities and human activities (agro-pastoral and tourism). The methods chosen have had to be adapted to the scarce and incomplete data. The volcanic hazards and their probability of occurrence were analysed on the basis of data available in the scientific literature and were supplemented by two field missions combining geography and hydro-geomorphology. Our study enabled us to map the hazards of ash fall, lava flows, lahars and avalanches of debris. Each hazard was spatialised by being ascribed an intensity. They are sometimes synchronous with the eruption sometimes they occur several months or years after a volcanic eruption. The results are the first step towards developing a volcanic risk management strategy, especially for the pastoral communities living around Lengai and for the growing tourist activities in this area.
DS1983-0614
1983
Ghezzo, C.Van bergen, M.J., Ghezzo, C., Ricci, C.A.Minette inclusions in the rhyodacitic lavas of Mt. Amiata(CentralItaly); mineralogical and chemical evidence of mixing between Tuscan and Roman type lavasJournal of Vol. Geotherm. Research, Vol. 19, No. 1-2, pp. 1-35ItalyMinette
DS1997-0077
1997
Ghiara, M.R.Barbieri, M., Ghiara, M.R., Segal, S.J.Trace element and isotope constraints on the origin of ultramafic lamprophyres from Los Alisos.Journal of South American Earth Science, Vol. 10, No. 1, pp. 39-48.ArgentinaGeochronology, Lamprophyres
DS202001-0004
2019
Ghiara, M.R.Cecchi, V.M., Rossi, M., Ghiara, M.R., Franza, A.An unrevealed treasure: a new Italian meteorite from the Royal Mineralogical Museum of Naples.Geology Today, Vol. 35, 6, pp. 212-216.Europe, Italymeteorite

Abstract: Naturalistic and geo?mineralogical museum collections are one of the most relevant sources for research on meteorites the world over. Here, we present the description of a new Italian meteorite that has been recently discovered at the Royal Mineralogical Museum of Naples in Italy.
DS200512-0556
2005
Ghias, S.R.Koglin, D.E.Jr., Ghias, S.R., King, S.D., Jarvis, G.T., Lowman, J.P.Mantle convection with reversing mobile plates: a benchmark study.Geochemistry, Geophysics, Geosystems: G3, Vol. 6, doi. 10.1029/2005 GC000924MantleTectonics, convection
DS200812-0402
2007
Ghias, S.R.Ghias, S.R., Jarvis, G.T.Mantle flow reversals in cylindrical Earth models.Physics of the Earth and Planetary Interiors, Vol. 165, 3-4, pp. 194-207.MantleModeling
DS200812-0403
2008
Ghias, S.R.Ghias, S.R., Jarvis, G.T.Mantle convection models with temperature and depth dependent thermal expansivity.Journal of Geophysical Research, Vol. 113, B8, B80408.MantleConvection
DS200812-0404
2008
Ghias, S.R.Ghias, S.R., Jarvis, G.T.Mantle convection models with temperature and depth dependent thermal expansivity.Journal of Geophysical Research, Vol. 113, August 15, B08408MantleConvection
DS201809-2000
2018
Ghienne, J-F.Brahimi, S., Ligeois, J-P., Ghienne, J-F., Munschy, M., Bourmatte, A.The Tuareg shield terranes revisited and extended towards the northern Gondwana margin: magnetic and gravimetric constraints.Earth Science Reviews, Vol. 185, Doi: 10.1016/j.earscirev. 2018.07.002Africa, AlgeriaGondwanaland

Abstract: Kimberlite is the host rock of diamonds and varies widely in geological and mineralogical features as well as color, processing capability, and dewatering characteristics. This study investigated the dewatering behavior of problematic Angolan kimberlites. The presence of clay minerals in kimberlite causes difficulties in dewatering due to high flocculant demand, poor supernatant clarity, and low settling rates. Identifying critical parameters governing the settling behavior will assist in managing the settling behavior of different kimberlite slurries. The influence of particle size, pH of the kimberlite slurry, cation exchange capacity, exchangeable sodium percentage, and smectite content of the kimberlite on the settling rate were investigated for 18 different African kimberlite samples. The settling rate and slurry bed compaction during natural settling were also measured for the kimberlite slurries. Seventeen different Angolan clay-rich kimberlites and one South African clay-rich kimberlite were tested, and, except for two kimberlites, colloidal stability was experienced during natural settling. The pH values of the kimberlite slurries ranged between 9 and 11, which is similar to the pH band where colloidal stability was found during earlier research. The results indicate that colloidal stable slurries were experienced with kimberlites that had exchangeable sodium percentages as low as 0.7%. The cation exchange capacity of the various kimberlites differentiated more distinctly between colloidal stability and instability. A new model is proposed whereby clay-rich kimberlites with a cation exchange capacity of more than 10cmol/kg will experience colloidal stability if the pH of the solvent solution is within the prescribed pH range of 9-11.The Trans-Saharan Belt is one of the most important orogenic systems constitutive of the Pan-African cycle, which, at the end of the Neoproterozoic, led to the formation of the Gondwana Supercontinent. It is marked by the opening and closing of oceanic domains, collision of continental blocks and the deformation of thick synorogenic sedimentary basins. It extends from north to south over a distance of 3000?km in Africa, including the Nigerian Shield and the Tuareg Shield as well as their counterparts beneath the Phanerozoic oil-rich North- and South-Saharan sedimentary basins. In this study, we take advantage of potential field methods (magnetism and gravity) to analyze the crustal-scale structures of the Tuareg Shield terranes and to track these Pan-African structures below the sedimentary basins, offering a new, >1000?km extent. The map interpretations are based on the classical potential field transforms and two-dimensional forward modeling. We have identified geophysical units and first-order bounding lineaments essentially defined owing to magnetic and gravimetric anomaly signatures. In particular, we are able to highlight curved terminations, which in the Trans-Saharan context have been still poorly documented. We provide for the first time a rheological map showing a categorization of contrasted basement units from the south of the Tuareg Shield up to the Atlas Belt. These units highlight the contrasted rheological behavior of the Tuareg tectonostratigraphic terranes during (i) the northerly Pan-African tectonic escape characteristic of the Trans-Saharan Belt and (ii) the North Sahara basin development, especially during intraplate reworking tied to the Variscan event. The discovery of a relatively rigid E-W oriented unit to the south of the Atlas system, and on which the escaping Pan-African terranes were blocked, offers a new perspective on the structural framework of the north-Gondwana margin. It will help to understand how occurred the rendezvous of the N-S oriented Pan-African terranes and the E-W oriented Cadomian peri-Gondwanan terranes.
DS201811-2565
2018
Ghiorso, M.Dasgupta, R., Van Tongeren, J.A., Watson, E.B., Ghiorso, M.Volatile bearing partial melts beneath oceans and continents; where, how much, and of what composition.American Journal of Science, Vol. 318, 1, pp. 141-165.Mantlemelting

Abstract: Besides depth and temperature, CO2 and H2O, are the two most important variables in stabilizing partial melts in the Earth's mantle. However, despite decades of experimental studies on the roles of these two volatile species in affecting mantle melting, ambiguity remains in terms of the stability, composition, and proportion of volatile-bearing partial melts at depths. Furthermore, the difference in the influence of H2O versus CO2 in production of mantle melts is often inadequately discussed. Here I first discuss how as a function of depth and concentration of volatiles, the peridotite + H2O versus peridotite + CO2 near-solidus melting conditions differ - discussing specifically the concepts of saturation of volatile-bearing phases and how the mode of storage of ‘water’ and carbon affects the near solidus melting relations. This analysis shows that for the Earth's mantle beneath oceans and continents, deep, volatile-induced melting is influenced mostly by carbon, with water-bearing carbonated silicate melt being the key agent. A quantitative framework that uses the existing experimental data, allows calculation of the loci, extent of melting, and major element compositions of volatile-bearing partial melts beneath oceans and continents. How the domains of volatile-bearing melt stability are affected when possible oxygen fugacity variation at depths in the mantle is taken into account is also discussed. I show that trace amount hydrous carbonated silicate melt is likely stabilized at two or more distinct depths in the continental lithospheric mantle, at depths ranges similar to where mid-lithospheric discontinuity (MLD) and lithosphere-asthenosphere boundary (LAB) have been estimated from seismology. Whereas beneath oceans, hydrous carbonated silicate melt likely remain continuously stable from the base of the thermal boundary layer to at least 200 km or deeper depending on the prevailing oxygen fugacity at depths. Hotter mantles, such as those beneath oceans, prevent sampling strongly silica-undersaturated, carbonated melts such as kimberlites as shallower basaltic melt generation dominates. Thick thermal boundary layers, such as those in cratonic regions, on the other hand allow production of kimberlitic to carbonatitic melt only. Therefore, the increasing frequency of occurrence of kimberlites starting at the Proterozoic may be causally linked to cooling and growth of sub-continental mantles through time.
DS1987-0249
1987
Ghiorso, M.S.Ghiorso, M.S.Chemical mass transfer in magmatic processes. III crystalgrowth, chemical diffusion and thermal diffusion in multicomponent silicate meltsContributions to Mineralogy and Petrology, Vol. 96, pp. 291-313GlobalExperimental Petrology, Silicate
DS1991-0566
1991
Ghiorso, M.S.Ghiorso, M.S.Thermodynamics of minerals and melts. (Review paper 1986-1990)Iugg Contributions In Volcanology, Geochemistry And Petrology, National, pp. 446-456GlobalReview -Thermometry, Mantle melts
DS1991-0567
1991
Ghiorso, M.S.Ghiorso, M.S.Thermodynamics of minerals and meltsInternational Union of Geodesy and Geophysics, 20th. meeting held Vienna August, pp. 446-456GlobalThermodynamics, Overview -review paper
DS1995-0093
1995
Ghiorso, M.S.Baker, M.B., Hurschmann, M.M., Ghiorso, M.S., Stolper, E.Compositions of near solidus peridotite melts from experiments and thermodynamic calculations.Nature, Vol. 375, No. 6529, May 25, pp. 308-311.GlobalPeridotite, Petrology -experimental
DS1995-1561
1995
Ghiorso, M.S.Reiners, P.W., Nelson, B.K., Ghiorso, M.S.Assimilation of felsic crust by basaltic magma: thermal limits and extents crustal contamination -mantle magmasGeology, Vol. 23, No. 6, June pp. 563-566MantleMagma, Felsic, basalt, contamination, geochemistry
DS1997-0393
1997
Ghiorso, M.S.Ghiorso, M.S.Thermodynamic models of igneous processesAnnual Review of Earth and Planetary Sciences, Vol. 25, pp. 221-242GlobalPetrology, Review - thermodynamics
DS1998-0623
1998
Ghiorso, M.S.Hirschmann, M.M., Ghiorso, M.S., Stolper, E.M.Calculation of peridotite partial melting from thermodynamic models of minerals and melts. #1Journal of Petrology, Vol. 39, No. 6, June 1, pp. 1091-1116.GlobalMethodology, techniques, experiments
DS1999-0309
1999
Ghiorso, M.S.Hirschmann, M.M., Ghiorso, M.S., Stopler, E.M.Calculation of peridotite partial melting from thermodynamic models of minerals and melts. III.Journal of Petrology, Vol. 40, No. 2, Feb. 1, pp. 297-314.MantleMelting - source composition
DS2002-0561
2002
Ghiribelli, B.Ghiribelli, B., Frzzotti, M-L., Palmeri, R.Coesite in eclogites of the Lanterman Range (Antartica): evidence from textural and Raman studies.European Journal of Mineralogy, Vol. 14,pp.355-60., Vol. 14,pp.355-60.AntarcticaUHP - coesite, metamorphism
DS2002-0562
2002
Ghiribelli, B.Ghiribelli, B., Frzzotti, M-L., Palmeri, R.Coesite in eclogites of the Lanterman Range (Antartica): evidence from textural and Raman studies.European Journal of Mineralogy, Vol. 14,pp.355-60., Vol. 14,pp.355-60.AntarcticaUHP - coesite, metamorphism
DS2002-0563
2002
Ghiribilli, B.Ghiribilli, B., Frezzotti, M.L., Palmeri, R.Coesite in eclogites of the Lanterman Range: evidence from textural and raman studiesEuropean Journal of Mineralogy, Vol.14,2,pp.355-60.AntarcticaEclogites
DS1989-1430
1989
Ghirnis, A.V.Solovova, I.P., Ghirnis, A.V., Kogarko, L.N., Ryabchik.., I.D.Geochemical pecularities of Prior Creek lamproites based on dat a of studyof Micro inclusions inolivines.(Russian) (Prairie CreekArk.?)Geochemistry International (Geokhimiya), (Russian), No. 10, October pp. 1449-1459RussiaLamproite, Geochemistry
DS201112-0364
2011
Ghobadi, M.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H & E., Keller, J.In situ trace element and U Pb and Sr and Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.48-50.Europe, GermanyKaiserstuhl
DS201112-0365
2011
Ghobadi, M.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H & E., Keller, J.In situ trace element and U Pb and Sr and Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.48-50.Europe, GermanyKaiserstuhl
DS201112-0366
2011
Ghobadi, M.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H.E., Keller, J.In-situ trace element and U-Pb, Sr and Nd isotope analysis of accessory phases in Kaiserstuhl cabonatites.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GermanyCarbonatite
DS201212-0237
2012
Ghobadi, M.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H.E., Keller, J.In situ trace element and U Pb and Sr Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.emc2012 @ uni-frankfurt.de, 1p. AbstractEurope, GermanyCarbonatite
DS201212-0238
2012
Ghobadi, M.Ghobadi, M., Gerdes, A., Kogarko, L., Brey, G.New dat a on the composition and hafnium isotopes of zircons from carbonatites of the Khibiny Massif.Doklady Earth Sciences, Vol. 446, 1, pp. 1083-1085.RussiaCarbonatite
DS201810-2321
2018
Ghobadi, M.Ghobadi, M., Gerdes, A., Kogarko, L., Hoefer, H., Brey, G.In situ LA-ICPMS isotopic and geochronological studies on carbonatites and phoscorites from the Guli Massif, Maymecha-Kotuy, polar Siberia.Geochemistry International, Vol. 56, 8, pp. 766-783.Russia, Siberiacarbonatite

Abstract: In this study we present a fresh isotopic data, as well as U-Pb ages from different REE-minerals in carbonatites and phoscorites of Guli massif using in situ LA-ICPMS technique. The analyses were conducted on apatites and perovskites from calcio-carbonatite and phoscorite units, as well as on pyrochlores and baddeleyites from the carbonatites. The 87Sr/86Sr ratios obtained from apatites and perovskites from the phoscorites are 0.70308-0.70314 and 0.70306-0.70313, respectively; and 0.70310-0.70325 and 0.70314-0.70327, for the pyrochlores and apatites from the carbonatites, respectively. Furthermore, the in situ laser ablation analyses of apatites and perovskites from the phoscorite yield ?Nd from 3.6 (±1) to 5.1 (±0.5) and from 3.8 (±0.5) to 4.9 (±0.5), respectively; ?Nd of apatites, perovskites and pyrochlores from carbonatite ranges from 3.2 (±0.7) to 4.9 (±0.9), 3.9 (±0.6) to 4.5 (±0.8) and 3.2 (±0.4) to 4.4 (±0.8), respectively. Laser ablation analyses of baddeleyites yielded an eHf(t)d of +8.5 (± 0.18); prior to this study Hf isotopic characteristic of Guli massif was not known. Our new in situ ?Nd, 87Sr/86Sr and eHf data on minerals in the Guli carbonatites imply a depleted source with a long time integrated high Lu/Hf, Sm/Nd, Sr/Rb ratios. In situ U-Pb age determination was performed on perovskites from the carbonatites and phoscorites and also on pyrochlores and baddeleyites from carbonatites. The co-existing pyrochlores, perovskites and baddeleyites in carbonatites yielded ages of 252.3 ± 1.9, 252.5 ± 1.5 and 250.8 ± 1.4 Ma, respectively. The perovskites from the phoscorites yielded an age of 253.8 ± 1.9 Ma. The obtained age for Guli carbonatites and phoscorites lies within the range of ages previously reported for the Siberian Flood Basalts and suggest essentially synchronous emplacement with the Permian-Triassic boundary.
DS202203-0347
2022
Ghobadi, M.Ghobadi, M., Brey, G.P., Gerdes, A., Hofer, H.E., Keller, J.Accessories in Kaiserstuhl carbonatites and related rocks as accurate and faithful recorders of whole rock age and isotopic composition.International Journal of Earth Science, Vol. 111, 2, 16p.Europe, Germanycarbonatite

Abstract: The accessories perovskite, pyrochlore, zirconolite, calzirtite and melanite from carbonatites and carbonate-rich foidites from the Kaiserstuhl are variously suited for the in situ determination of their U-Pb ages and Sr, Nd- and Hf-isotope ratios by LA-ICP-MS. The 143Nd/144Nd ratios may be determined precisely in all five phases, the 176Hf/177Hf ratios only in calzirtite and the 87Sr/86Sr ratios in perovskites and pyrochlores. The carbonatites and carbonate-rich foidites belong to one of the three magmatic groups that Schleicher et al. (1990) distinguished in the Kaiserstuhl on the basis of their Sr, Nd and Pb isotope ratios. Tephrites, phonolites and essexites (nepheline monzogabbros) form the second and limburgites (nepheline basanites) and olivine nephelinites the third. Our 87Sr/86Sr isotope data from the accessories overlap with the carbonatite and olivine nephelinite fields defined by Schleicher et al. (1990) but exhibit a much narrower range. These and the ?Nd and ?Hf values plot along the mantle array in the field of oceanic island basalts relatively close to mid-ocean ridge basalts. Previously reported K-Ar, Ar-Ar and fission track ages for the Kaiserstuhl lie between 16.2 and 17.8 Ma. They stem entirely from the geologically older tephrites, phonolites and essexites. No ages existed so far for the geologically younger carbonatites and carbonate-rich foidites except for one apatite fission track age (15.8 Ma). We obtained precise U-Pb ages for zirconolites and calzirtites of 15.66, respectively 15.5 Ma (±?0.1 2?) and for pyrochlores of 15.35?±?0.24 Ma. Only the perovskites from the Badberg soevite yielded a U-P concordia age of 14.56?±?0.86 Ma while the perovskites from bergalites (haüyne melilitites) only gave 206Pb/238U and 208Pb/232Th ages of 15.26?±?0.21, respectively, 15.28?±?0.48 Ma. The main Kaiserstuhl rock types were emplaced over a time span of 1.6 Ma almost 1 million years before the carbonatites and carbonate-rich foidites. These were emplaced within only 0.32 Ma.
DS201804-0710
2018
Ghodke, S.S.Kokandakar, G.K., Ghodke, S.S., Rathna, K., Kumar, K.V.Crustal growth along Proterozoic SE India: parameterization of mantle sources, melting, mechanism, and magma differentiation processes.Journal of the Geological Society of India, Vol. 91, 2, pp. 135-146.Indiamagmatism
DS201804-0711
2018
Ghodke, S.S.Kokandakar, G.K., Ghodke, S.S., Rathna, K., Kumar, K.V.Density, viscosity and velocity (ascent rate) of alkaline magmas.Journal of the Geological Society of India, Vol. 91, 2, pp. 135-146.IndiaPrakasam alkaline province

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

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

Abstract: Formation of the fragments of the wall-rock during dyking is one of the important manifestations of instantaneous magmatic events. This process is well documented at shallower depths of Earth’s crust but not at deeper levels. In this paper the in situ xenoliths of host rock nepheline syenite within a micro-shonkinite dyke emplaced at mid-crustal depths is described and the fractal theory applied to evaluate origin of the xenoliths. The nepheline syenite xenoliths are angular to oval shaped and sub-millimetre to ~50 cm long. The xenoliths are matrix supported with clasts and matrix being in equal proportions. Partly detached wall-rock fragments indicate incipient xenolith formation, which suggested that the model fragmentation processes is solely due to dyke emplacement. Fractal analytical techniques including clast size distribution, boundary roughness fractal dimension and clast circularity was carried out. The fractal data suggests that hydraulic (tensile) fracturing is the main process of host rock brecciation. However, the clast size and shape are further affected by postfragmentation processes including shear and thermal fracturing, and chemical erosion. The study demonstrates that dyking in an isotropic medium produces fractal size distributions of host rock xenoliths; however, post-fragmentation processes modify original fractal size distributions.
DS2000-0335
2000
Ghods, A.Ghods, A.Melt migration modeling in partially molten upper mantleNational Library MF 5976 GSC, ThesisMantleGeochemistry - melting
DS2001-1098
2001
Ghods, A.Sobouti, F., Ghods, A., Arkani-Hamed, J.On the advection of sharp material interfaces in geodynamic problems: entrainment of the D layer.Journal of Geodynamics, Vol. 31, No. 5, pp. 459-79.MantleConvection - chemistry
DS2002-0564
2002
Ghods, A.Ghods, A.Is small scale convection responsible for the formation of thick igneous crust along volcanic passive margins?Geophysical Research Letters, Vol. 29,10,May15,pp. 17-MantleSubduction
DS201603-0390
2016
Ghogomu, T.R.Kanouo, N.S., Ekomane, E., Yongue, R.F., Njonfang, E., Zaw, K., Changian, M., Ghogomu, T.R., Lentz, D.R., Venkatesh, A.S.Trace elements in corundum, chrysoberyl, and zircon: application to mineral exploration and provenance study of the western Mamfe gem clastic deposits ( SW Cameroon, Central Africa).Journal of African Earth Sciences, Vol. 113, pp. 35-50.Africa, CameroonGeochemistry

Abstract: Trace element abundances in three indicator minerals (corundum, chrysoberyl, and zircon grains) from the western Mamfe gem placers, as determined by LA-ICP-MS analytical techniques, are shown to be sensitive to their crystallization conditions and source rock types. Corundum is dominantly composed of Al (standardized at 529,300 ppm), Fe (2496-12,899 ppm), and Ti (46-7070 ppm). Among element ratios, Fe/Mg (73-1107), Fe/Ti (0.5-245.0), Ti/Mg (1-175), and Ga/Mg (4-90) are generally higher whereas, Cr/Ga (<0.072) is low. The Fe (?12,899), Ga (?398), Mg (2-62), Cr (1.1-33.0), and V (3.0-93.0) contents (in ppm) mostly typify corundum grains formed in magmatic rocks, although some are metamorphic affiliated. A very higher Ti and significantly low Ga, Ta and Nb contents in some blue grains, suggest interesting concentrations of those high-tech metals in their source rocks. Chrysoberyl is dominantly composed of Al (standardized at 425,000 ppm) and Be (62701-64371 ppm). Iron (7605-9225 ppm), Sn (502-3394 ppm), and Ti (33-2251 ppm) contents are high, whereas Ga (333-608 ppm), Ta (<456.0 ppm), and Nb (<3.0 ppm) are significantly low. The high (Be and Sn) and significantly low Ga-Rb abundances, and Ta > Nb in the western Mamfe chrysoberyls show that they were crystallized in granitic pegmatites, with some of those source rocks being enriched in Ta and Sn. Zirconium oxide (ZrO2: standardized at 66.1 wt.%)) is the only major oxide in analysed coarse-grained zircons. Within the minor elementary suites: Hf (4576-12,565 ppm) and Y (48-2805 ppm) contents are significantly high. The trace element suites include: Th (7-1565 ppm), U (13-687 ppm), and ?REE (50-2161 ppm), whose values are significantly low. The (Yb/Sm)N, Ce/Ce*, and Eu/Eu* anomalies range from 1.0 to 227.0, 0 to 308, and 0.08 to 1.7 respectively. They are Hf-Y-HREE enriched and depleted zircons mainly crystallized in magmatic oxidized environments. They were mainly sorted from granitoids, syenites and kimberlites.
DS201905-1069
2019
Gholoizade, K.Raeisi, D., Gholoizade, K., Nayebi, N., Babazadeh, S., Nejadhadad, M.Geochemistry and mineral composition of lamprophyre dikes, central Iran: implications for petrogenesis and mantle evolution.Journal of Earth System Science, Vol. 128:74Europe, Iranlamprophyre

Abstract: Late Proterozoic-Early Cambrian magmatic rocks that range in composition from mafic to felsic have intruded into the Hour region of the central Iranian micro-continent. The Hour lamprophyres are alkaline, being characterized by low contents of SiO2 and high TiO2, Mg# values, high contents of compatible elements, and are enriched in LREE and LILE but depleted in HFSE. Mineral chemistry studies reveal that the lamprophyres formed within a temperature range of ?1200? to 1300?C and relatively moderate pressure in subvolcanic levels. The Hour lamprophyres have experienced weak fractional crystallization and insignificant crustal contamination with more primitive mantle signatures. They were derived from low degree partial melting (1-5%) of the enriched mantle characterized by phlogopite/amphibole bearing lherzolite in the spinel-garnet transition zone at 75-85 km depth, and with an addition of the asthenospheric mantle materials. We infer the Hour lamprophyres to be part of the alkaline rock spectrum of the Tabas block and their emplacement, together with that of other alkaline complexes in the central Iran, was strongly controlled by pre-existing crustal weakness followed by the asthenosphere-lithospheric mantle interaction during the Early Cambrian.
DS1990-0565
1990
Ghomshei, M.M.Ghomshei, M.M., Arkani-Hamed, J., Strangway, D.W., Russell, R.D.Underplating of oceanic lithosphere in the Archean: a possible mechanism for the formation of ArcheankomatiitesTectonophysics, Vol. 172, No. 3-4, February 1, pp. 291-302GlobalArchean, Komatiites
DS1991-0795
1991
Ghomshei, M.M.Jessop, A.M., Ghomshei, M.M., Drury, M.J.Geothermal energy in CanadaGeothermics, Vol. 20, No. 5-6, pp. 369-385CanadaGeothermal energy, Overview
DS1998-0736
1998
GhoseKent, R.W., Paul, D.K., Basu, Ghose, KemptonMafic alkaline intrusions in the Damodar Valley, India: the micaceous kimberlite - lamproite connection revisit7th International Kimberlite Conference Abstract, pp. 411-13.IndiaAlkaline rocks, Classification
DS1994-0615
1994
Ghose, A.K.Ghose, A.K.Small scale mining: a global overviewA.a.balkema, 380pGlobalEconomics, policies, overview, Book -table of contents
DS1994-0616
1994
Ghose, A.K.Ghose, A.K.Small scale mining - a global overview..policies, geology, status, economics.A.a. Balkema Publishing, 400p.GlobalMining- placers, Alluvials -not specific to diamonds
DS1940-0209
1949
Ghose, C.Ghose, C.A Petrochemical Study of the Lamprophyres and Associated Intrusive Rocks of the Jharia Coal Field.Quarterly Journal of Geology MIN. MET. SOC. INDIA., Vol. 21, No. 4, PP. 133-147.IndiaBlank
DS1970-0085
1970
Ghose, C.Ghose, C.On the Occurrence of a Peridotite Dyke from Richugutu PalamaProceedings SECOND Symposium UPPER MANTLE PROJECT., P. 349.IndiaBlank
DS1970-0920
1974
Ghose, D.B.Haldar, D., Ghose, D.B.Tectonics of the Kimberlites Around Majhgawan, Madhya PradesIndia Geological Survey Spec. Publishing, PP. 47-48.India, Madhya PradeshBlank
DS2002-1672
2002
Ghose, I.Vladkar, S.G., Ghose, I.U rich pyrochlore in carbonatite of Newania, RajasthanNeues Jahrbuch fur Mineralogie - Monatshefte, No.3, March,ppp.97-106.IndiaCarbonatite
DS1992-0839
1992
Ghose, N.C.Kent, R.W., Ghose, N.C., Paul, P.R., Hassan, M.J., Saunders, A.D.Coal-magma interaction: an integrated model for the emplacement of cylindrical intrusionsGeological Magazine, Vol. 129, No. 6, pp. 753-762IndiaLamproite, Magmas
DS200612-0454
2005
Ghose, N.C.Ghose, N.C., Mukherjee, D., Chatterjee, N.Plume generated Mesoproterozoic mafic-ultramafic magmatism in the Chotanagpur mobile belt of eastern Indian shield margin.Journal of Geological Society of India, Vol. 66, 6, pp. 725-740.IndiaMagmatism
DS201012-0102
2010
Ghose, N.C.Chatterjee, N.,Ghose, N.C.Metamorphic evolution of the Naga Hills eclogite and blueschist northeast India: implications for early subduction of the Indian Plate under Burma microplateJournal of Metamorphic Geology, Vol. 28, 2, pp. 209-225.IndiaSubduction
DS201412-0284
2014
Ghose, T.Ghose, T.Comet strike to blame for Canada's iconic Sudbury Basin.Scientific American, 2p.Canada, OntarioImpacts
DS2002-0280
2002
GhoshChaudhuri, A.K., Saha, Deb, Mukherjee, GhoshThe Purana basins of southern cratonic province of India - a case for mesoproterozoic fossil rifts.Gondwana Research, Vol. 5, No. 1, pp. 23-34.IndiaCraton - rifting, tectonics
DS200812-0405
2008
Ghosh, A.Ghosh, A., Holt, W.E., Wen, L., Haines, A.J., Flesch, L.M.Joint modeling of lithosphere and mantle dynamics elucidating lithosphere mantle coupling.Geophysical Research Letters, Vol. 35, 16, L16309-10.MantleTectonics
DS201212-0239
2012
Ghosh, A.Ghosh, A., Holt, W.E.Plate motions and stresses from global dynamic models.Science, Vol. 335, 6070, pp. 838-843.MantleGeodynamics
DS201312-0309
2013
Ghosh, A.Ghosh, A., Becker, T.W., Humphreys, E.D.Dynamics of the North American continent.Geophysical Journal International, Vol. 194, 2, pp. 651-669.United States, CanadaGeodynamics
DS201603-0430
2015
Ghosh, A.Wang, X., Holt, W.E., Ghosh, A.Joint modeling of lithosphere and mantle dynamics: evaluation of constraints from global tomography models.Journal of Geophysical Research,, Vol. 120, 12, pp. 8633-8655.MantleGeodynamics

Abstract: With the advances in technology, seismological theory, and data acquisition, a number of high-resolution seismic tomography models have been published. However, discrepancies between tomography models often arise from different theoretical treatments of seismic wave propagation, different inversion strategies, and different data sets. Using a fixed velocity-to-density scaling and a fixed radial viscosity profile, we compute global mantle flow models associated with the different tomography models and test the impact of these for explaining surface geophysical observations (geoid, dynamic topography, stress, and strain rates). We use the joint modeling of lithosphere and mantle dynamics approach of Ghosh and Holt (2012) to compute the full lithosphere stresses, except that we use HC for the mantle circulation model, which accounts for the primary flow-coupling features associated with density-driven mantle flow. Our results show that the seismic tomography models of S40RTS and SAW642AN provide a better match with surface observables on a global scale than other models tested. Both of these tomography models have important similarities, including upwellings located in Pacific, Eastern Africa, Iceland, and mid-ocean ridges in the Atlantic and Indian Ocean and downwelling flows mainly located beneath the Andes, the Middle East, and central and Southeast Asia.
DS202002-0214
2020
Ghosh, A.Paul, J., Ghosh, A.Evolution of cratons through the ages: a time dependent study.Earth and Planetary Science Letters, Vol. 531, 13p. PdfMantlecratons

Abstract: The viscosity of cratons is key to understanding their long term survival. In this study, we present a time-dependent, full spherical, three dimensional mantle convection model to investigate the evolution of cratons of different viscosities. The models are initiated from 409 Ma and run forward in time till the present-day. We impose a surface velocity boundary condition, derived from plate tectonic reconstruction, to drive mantle convection in our models. Cratons of different viscosities evolve accordingly with the changing velocity field from their original locations. Along with the viscosity of cratons, the viscosity of the asthenosphere also plays an important role in cratons' long term survival. Our results predict that for the long-term survival of cratons they need to be at least 100 times more viscous than their surroundings and the asthenosphere needs to have a viscosity of the order of 1020 Pa-s or more.
DS201112-0706
2011
Ghosh, B.Mukhopadhyay, S., Ray, J., Chattopadhyay, B., Sengupta, S., Ghosh, B., Mukhopadhyay, S.Significance of mineral chemistry of syenites and associated rocks of Elagiri complex, southern granulite terrane of the Indian shield.Journal of the Geological Society of India, Vol. 77, pp. 113-129.IndiaAlkaline rocks, magmatism
DS2003-0461
2003
Ghosh, D.Ghosh, D.Aeromagnetic response over northern margin of eastern Gnat mobile belt, DeogarhGeological Society of India Journal, Vol. 62, 1, pp. 43-50.IndiaGeophysics - magnetics
DS200412-0656
2003
Ghosh, D.Ghosh, D.Aeromagnetic response over northern margin of eastern Gnat mobile belt, Deogarh district, Orissa.Geological Society of India Journal, Vol. 62, 1, pp. 43-50.IndiaGeophysics - magnetics
DS200412-0657
2004
Ghosh, D.Ghosh, D.Aeromagnetic signatures of pre-Aravalli Bhilwara Supergroup rocks in Agucha Malpura Jaipur Block, Rajasthan.Journal Geological Society of India, Vol. 63, 5, pp. 483-493.India, RajasthanGeophysics - magnetics
DS1975-0754
1978
Ghosh, D.B.Halder, D., Ghosh, D.B.Tectonics of the Kimberlites Around Majhgawan Madhya Pradesh, IndiaGeological Survey of India M.P., No. 34, pp. 1-13.IndiaTectonics, Deposit - Majhgawan
DS201909-2033
2019
Ghosh, D.B.Deng, J., Karki, B.B., Ghosh, D.B., Lee, K.K.M.First principles study of FeO2Hx solid and melt system at high pressures: implications for ultralow-velocity zones. ( Lower mantle may have a wet bottom** citation note) Journal of Geophysical Research: Solid Earth, Vol. 124, pp. 4566-4575.Mantleboundary

Abstract: Ultralow?velocity zones (ULVZs) are 5-40?km?thick patches lying above Earth's core-mantle boundary. They are characterized with anomalously low seismic velocities compared with the ambient mantle and may contain important clues on the thermochemical evolution of the Earth. A recent experimental study argued that ULVZs may be caused by the accumulation of pyrite?type FeO2Hx (P phase) at the bottom of the mantle. Here for the first time, we systematically study the thermoelastic properties of both FeO2Hx solid and liquid phases. We find that P phase is likely melted near the core-mantle boundary and thus cannot be the source of ULVZs. Furthermore, in order for the molten product of P phase to cause ULVZs, the dense and nearly inviscid melts must be dynamically stable and confined within the ULVZs, which requires that the mantle is highly viscous and/or convects vigorously.
DS1998-0330
1998
Ghosh, J.G.De Wit, M.J., Ghosh, J.G., Bowring, S., Ashwal, L.Late Neoproterozoic shear zones in Madagascar and India: Gondwana"life-lines".Journal of African Earth Sciences, Vol. 27, 1A, p. 58. AbstractAfrica, Madagascar, IndiaGondwana, Tectonics
DS1998-0504
1998
Ghosh, J.G.Ghosh, J.G., Zartman, R.E., De Wit, M.J.Re-evaluation of tectonic framework of southern most India: new uranium-lead (U-Pb)geochronological and structural data.Journal of African Earth Sciences, Vol. 27, 1A, p. 86. AbstractIndia, southTectonics - not specific to diamonds, Geochronology
DS200412-0658
2004
Ghosh, J.G.Ghosh, J.G.3.56 Ga tonalite in the central part of the Bastar Craton, India: oldest Indian date.Journal of Asian Earth Sciences, Vol. 23, 3, July, pp. 359-364.IndiaGeochronology
DS1998-1314
1998
Ghosh, M.Sengupta, S., Ghosh, M., Chattopadhyay, A.Petrology of post Archean magmatic rocks in the eastern Indian CratonJournal of Geological Society India, Vol. 51, No. 1, Jan. 1, pp. 31-42IndiaCraton, Magmatism
DS201801-0004
2017
Ghosh, P.Benjamin, F.R., Ghosh, P., Viladkar, S.G.A secular variation of stable isotope record in global carbonatite magma.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p.11.Globalcarbonatites

Abstract: Carbonatites are magmatic rocks, origin of these relates to the involvement of mantle fluid. Thus they provide indirect method to understand the sub-continental upper mantle fluid composition. The first report on carbonatites and the later eruption of the natrocarbonatite paved way for investigating the heterogeneity of the mantle with depth and since then, many other occurrences have been found worldwide, offering suitable samples for probing the mantle. We present record of stable isotopic composition of carbonatites spanning Precambrian, Proterozoic to Phanerozoic to Recent time based on their temporal occurrences and global distribution in the geological record. We consider the various tectonic settings from which carbonatites have been reported, the underlying eruption mechanisms taking into account the tectonic significance of their occurrence and their imprints on surrounding rocks. This account covers carbonatites and associated rocks from different continents with a prime focus on carbon and oxygen isotopes. Carbon and oxygen isotope composition vary significantly within time spans. These variations depend on other factors besides mantle composition i.e. carbonate mineralogy and alteration processes that can cause a shift from original compositions. We envisage the use of stable isotope records to address the secular variation of crustal mixing / contamination process in geological time. Many of these secular variation are abrupt and probably indicate shift in the tectonic forcing - a vital factor responsible for driving the secular trend.
DS202004-0511
2020
Ghosh, P.Fosu, B.R., Ghosh, P., Viladkar, S.G.Clumped isotope geochemistry of carbonatites in the north-western Deccan igneous province: aspects of evolution, post-depositional alteration and mineralization.Geochimica et Cosmochimica Acta, Vol. 274, pp. 118-135.Indiacarbonatite

Abstract: Carbonatites crystallise along a wide range of solidus temperatures and are commonly affected by post-magmatic textural re-equilibration and diagenesis. Further insights into the formation and modification of carbonatites are provided using carbon, oxygen and clumped isotope (?47) data of rocks from spatially associated Amba Dongar and Siriwasan alkaline complexes in the north-western Deccan igneous province, India. We derive apparent equilibrium blocking temperatures to help constrain the thermal evolution of the different rock types found within the alkaline complexes in a petrographic context. The apparent temperatures for the carbonatites are significantly low but are consistent with reports on other global carbonatites and model predictions. Rapidly cooled Oldoinyo Lengai natrocarbonatite yielded similar low temperatures, even in the absence of bulk isotopic alteration. The isotopic proxies and petrographic observations favour both isotopic exchange reactions and diagenesis in altering ?47 values in calciocarbonatites. Diagenetic reactions are however strongly favoured, as secondary calcites in nephelinites and ferrocarbonatites record much lower temperatures than in the calciocarbonatites, highlighting the effect of fluids and diagenetic reactions in 13C18O bond ordering in carbonatites. Variations in the CO isotope data reveal the coupling of fractional crystallisation and post-magmatic fluid-rock interactions on bulk rock composition. After emplacement, the resetting of clumped isotope signatures in carbonatites is facilitated by post-magmatic processes in both open and closed systems.
DS202105-0763
2021
Ghosh, P.Fosu, B.R., Ghosh, P., Weisenberger, T.B., Spurgin, S., Viladar, S.G.A triple oxygen isotope perspective on the origin, evolution, and diagenetic alteration of carbonatites.Geochimica et Cosmochimica Acta, Vol. 299, pp. 52-68. pdfMantlecarbonatites

Abstract: Carbonatites are unique magmatic rocks that are essentially composed of carbonates, and they usually host a diverse suite of minor and accessory minerals. To provide additional insights on their petrogenesis, triple oxygen isotope analyses were carried out on carbonatites from sixteen localities worldwide in order to assess the behaviour of oxygen isotopes (mass-dependent fractionation) during their formation. The study evaluates the mineralogical differences, i.e., calcite, dolomite, ankerite, and Na-carbonates, and the mode of emplacement (intrusive or extrusive) in the mantle-derived carbonatites to further constrain the triple oxygen isotopic composition (??17O) of the upper mantle. ??17O values in the intrusive calcite carbonatites vary between ?0.003 to ?0.088‰ (n?=?20) and ?0.024 to ?0.085‰ (n?=?5) in the dolomite varieties. We surmise that the magnitude of isotopic fractionation in the different carbonate phases during their formation is similar and thus, the observed variations are independent of mineralogy and may be related to alteration in the rocks. Taking the samples that classify as primary igneous carbonatites altogether, the average ??17O value of the mantle is estimated as ?0.047?±?0.027‰ (1SD, n?=?18) which overlaps those of other mantle rocks, minerals and xenoliths, indicating that the mantle has a relatively homogenous oxygen isotope composition. Two ankerite carbonatites have identical ??17O values as calcite but a few samples, together with pyroclastic tuffs have significantly lower ??17O values (?0.108 to ?0.161‰). This deviation from mantle ??17O signature suggests diagenetic alteration (dissolution and recrystallisation) and mixing of carbonate sources (juvenile and secondary carbonates) which is consistent with the high ?18O and clumped isotope (?47) values recorded in the pyroclastic and ankeritic rocks. In summary, diagenetic alteration driven by fluid-rock interaction at low temperatures, sub-solidus re-equilibration with magmatic waters, and the incorporation of secondary carbonates altogether facilitate the alteration of original isotopic compositions of carbonatites, obliterating their primary mantle signatures.
DS200412-1491
2003
Ghosh, R.N.Pal, T., Chakaborty, P.P., Ghosh, R.N.PGE distribution in chromite placers from Andaman ophiolite and its boninitic parentage.Geological Society of India Journal, Vol. 62, 6, pp. 671-679.IndiaAlkaline rocks, not specific to diamonds
DS200612-0456
2006
Ghosh, S.Ghosh, S., Ohtani, E., Litasov, K.D., Suzuki, A.Density of carbonated basaltic melt at the conditions of Earth's upper mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 15, abstract only.MantleMelting
DS200612-0457
2006
Ghosh, S.Ghosh, S., Ohtani, E., Litasov, K.D., Suzuki, A., Terasaki, H.Solidus of carbonated peridotite tp 20 GPa.International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p. 140.MantleMelting
DS200612-0825
2006
Ghosh, S.Litasov, K.D., Ohtani, E., Kagi, H., Ghosh, S.Water partitioning between olivine and wadsleyite near 410 km seismic discontinuity.International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p.102.MantleDiscontinuity - width
DS200712-0358
2007
Ghosh, S.Ghosh, S., Fareeduddin, Viswanathan, S.Chondritic features in a Diamondiferous rock, Majhgawan, Central India.Journal of the Geological Society of India, Vol. 69, 4, p. 863 ( 1p.)IndiaPetrography
DS200812-0406
2007
Ghosh, S.Ghosh, S., Ohtani, E., Litasov, K., Suzuki, A., Sakamaki, T.Stability of carbonated magmas at the base of the Earth's upper mantle.Geophysical Research Letters, Vol. 34, 22, pp. L22312.MantlePetrology
DS200912-0250
2009
Ghosh, S.Ghosh, S., Ohtani, E., Litasov, K.Partial melting of peridotite + CO2 and origin of kimberlite melt in the deep mantle.Goldschmidt Conference 2009, p. A433 Abstract.MantleMelting
DS200912-0251
2009
Ghosh, S.Ghosh, S., Ohtani, E., Litsov, K.D., Terasaki, H.Solidus of carbonated peridotite from 10 to 20 GPa and origin of magnesiocarbonatite melt in the Earth's deep mantle.Chemical Geology, Vol. 262, 1-2, May 15, pp. 17-28.MantleCarbonatite
DS201112-0367
2011
Ghosh, S.Ghosh, S., Schmidt, M.W.Stability of phase D at high pressure and temperature: implications for the role of fluids in the deep mantle.Goldschmidt Conference 2011, abstract p.912.MantleWater, subduction
DS201412-0285
2014
Ghosh, S.Ghosh, S., Litasov, K., Ohtani, E.Phase relations and melting of carbonated peridotite between 10 and 20 Gpa: a proxy for alkali and CO2 rich silicate melts in the deep mantle.Contributions to Mineralogy and Petrology, Vol. 167, pp. 964-972.MantleMelting
DS201412-0288
2014
Ghosh, S.Ghosh, S., Schmidt, M.W.Melting of Phase D in the lower mantle and implications for recycling and storage of H2O in the deep mantle.Geochimica et Cosmochimica Acta, Vol. 145, pp. 72-88.MantleWater storage
DS201412-0750
2014
Ghosh, S.Rohrbach, A., Ghosh, S., Schmidt, M.W., Wijnrans, C.H., Klemme, S.The stability of Fe-Ni carbides in the Earth's mantle: evidence for a low Fe-Ni-C melt fraction in the deep mantle.Earth and Planetary Science Letters, Vol. 388, pp. 211-221.MantleMelting - mentions diamond
DS201607-1348
2016
Ghosh, S.Ghosh, S.REE enriched carbonatite from Kamthai area, Barmer district, Rajasthan, India: imprints of a delta34S depleted mantle source.IGC 35th., Session The Deep Earth 1 p. abstractIndiaCarbonatite
DS202001-0050
2020
Ghosh, S.Yaxley, G.M., Ghosh, S., Kiseeva, E.S., Mallick, A., Spandler, C., Thomson, A.R., Walter, M.J.Co2 rich melts in the earth.IN: Deep Carbon: past to present. Editors Orcutt, Danielle, Dasgupta, pp. 129-162.Mantlemelting

Abstract: This chapter reviews the systematics of partial melting of mantle lithologies - like peridotite and eclogite - in the presence of carbon dioxide. It discusses the composition of mantle-derived magmas generated in the presence of carbon dioxide and whether magmas erupted on Earth’s surface resemble carbonated magmas from the mantle. It reviews how the production of carbon dioxide-rich magma in the mantle varies as a function of tectonic settings - beneath continents and oceans and in subduction zones - and time.
DS202009-1620
2020
Ghosh, S.Choudhary, S., Sen, K., Kumar, S., Rana, S., Ghosh, S.Forsterite repricipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic-alkaline-carbonatite complex, Meghalaya, NE India.Geological Magazine, 10.1017/S001675 68200000631 12p.Indiacarbonatites

Abstract: Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2-H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2-H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution-precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2-H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.
DS202009-1651
2020
Ghosh, S.Pattnaik, J., Ghosh, S., Dongre, A.Plume activity and carbonated silicate melt metasomatism in Dharwar cratonic lithosphere: evidence from peridotite xenoliths in Wajrakarur kimberlites.Lithos, in press available, 63p. PdfIndiadeposit - Wajrakarur

Abstract: We report petrography, mineralogy, major- and trace-element compositions of a rare selection of spinel- and garnet-bearing peridotite xenoliths and single crystals separated from peridotites hosted in the Mesoproterozoic Wajrakarur kimberlites from the Eastern Dharwar craton (EDC), India. These ultramafic xenoliths consist of olivine (modal 74-82 vol%) with Fo92-93, clinopyroxene, orthopyroxene, spinel, garnet, and/or ilmenite. Calculated equilibrium pressure and temperature conditions are 2.5-5.0?GPa and 710-1179?°C for these peridotites, which suggests residence depths >160?km near the base of the Dharwar cratonic lithospheric mantle. Garnet in these ultramafic rocks [with Mg#?=?molar (Mg/(Mg?+?Fetotal)?×?100 of 80-88] displays either “sinuous” LREE-enriched patterns with depletion in Gd and Er for harzburgites or “normal” LREE-depleted, HREE-enriched patterns for lherzolites. Two groups of clinopyroxenes (group-I and group-II) were also observed with high LREE (LaN?>?10) and low LREE (LaN?
DS202012-2239
2020
Ghosh, S.Pattanik, J., Demouchy, S., Ghosh, S.Low hydrogen concentrations in Dharwar cratonic lithosphere inferred from peridotites, Wajrakarur kimberlites field: implications for mantle viscosity and carbonated silicate melt metasomatism.Precambrian Research, in press available 15p. PdfIndiadeposit - Wajrakarur

Abstract: Hydrogen as an atomic impurity in mantle minerals is recurrently proposed as a key element impacting significantly on many mantle properties and processes such as melting temperature and mechanical strength. Nevertheless, interpretation based on the natural samples remains weak as we do not have yet a robust world-wild database for hydrogen concentrations in mantle minerals and rocks. Here, we report the first hydrogen concentrations in nominally anhydrous minerals from a rare selection of ultramafic rocks and minerals embedded in Mesoproterozoic Wajrakarur kimberlites (Eastern Dharwar craton, India). Based on key chemical elements, we demonstrate that olivine, pyroxenes and garnet from the Dharwar craton are of mantle origin. We quantify the hydrogen concentrations using Fourier transform infrared spectroscopy (FTIR) and mineral-specific FTIR calibrations. Calculated hydrogen concentrations are, in average, 18 ppm wt H2O in olivine, 70 ppm wt H2O in orthopyroxene and 207 ppm wt H2O in clinopyroxene. Garnet has highly variable hydrogen concentration ranging from 0 to 258 ppm wt H2O, probably influenced by nano-scale inclusions. The average of clean garnet spectra yields 14.5 ppm wt H2O. The reconstructed hydrogen bulk concentrations of Dharwar peridotites yields ppm wt H2O. This value is two to five times lower than the estimated hydrogen concentration in the lithospheric mantle, and agree well with the lower range of hydrogen bulk concentration from the current data base for the upper mantle minerals transported by kimberlites from other cratons (e.g., South Africa, Siberia). The low hydrogen concentration in mantle minerals, together with petrological and geochemical evidence of carbonated silicate melt metasomatism in Dharwar cratonic lithospheric mantle, suggest that these xenoliths are possibly related to proto-kimberlite melts with low water activity prior to being transported to the surface by the Mesoproterozoic Wajrakarur kimberlites. These observations, valid to a depth of ~165-km, suggest that cratonic lithosphere beneath the Dharwar craton may not be particularly indicative of an abnormal hydrogen-rich southern Indian lithosphere in the late Archean and that hydroxylic weakening in olivine would induced a negligible effect on the mantle viscosity of Indian subcontinent.
DS202101-0003
2020
Ghosh, S.Choudhary, S., Sen, K., Kumar, S., Rana, S., Ghosh, S.Forsterite reprecipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic-alkaline-carbonatite complex, Meghalaya, NE India.Geological Magazine, doi:1017/S001 6756820000631, 12p.Indiadeposit - Sung Valley

Abstract: Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2-H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2-H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution-precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2-H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.
DS202102-0214
2021
Ghosh, S.Pattnaik, J., Demouchy, S., Ghosh, S.Low hydrogen concentrations in Dharwar cratonic lithospheric inferred from peridotites, Wajrakarur kimberlite field: implications for mantle viscosity and carbonated silicate melt metasomatism.Precambrian Research, Vol. 352, doi.org/1016 /j.precamres .2020.105982 15p. PdfIndiadeposit - Wajrakarur

Abstract: Hydrogen as an atomic impurity in mantle minerals is recurrently proposed as a key element impacting significantly on many mantle properties and processes such as melting temperature and mechanical strength. Nevertheless, interpretation based on the natural samples remains weak as we do not have yet a robust world-wild database for hydrogen concentrations in mantle minerals and rocks. Here, we report the first hydrogen concentrations in nominally anhydrous minerals from a rare selection of ultramafic rocks and minerals embedded in Mesoproterozoic Wajrakarur kimberlites (Eastern Dharwar craton, India). Based on key chemical elements, we demonstrate that olivine, pyroxenes and garnet from the Dharwar craton are of mantle origin. We quantify the hydrogen concentrations using Fourier transform infrared spectroscopy (FTIR) and mineral-specific FTIR calibrations. Calculated hydrogen concentrations are, in average, 18 ppm wt H2O in olivine, 70 ppm wt H2O in orthopyroxene and 207 ppm wt H2O in clinopyroxene. Garnet has highly variable hydrogen concentration ranging from 0 to 258 ppm wt H2O, probably influenced by nano-scale inclusions. The average of clean garnet spectra yields 14.5 ppm wt H2O. The reconstructed hydrogen bulk concentrations of Dharwar peridotites yields ppm wt H2O. This value is two to five times lower than the estimated hydrogen concentration in the lithospheric mantle, and agree well with the lower range of hydrogen bulk concentration from the current data base for the upper mantle minerals transported by kimberlites from other cratons (e.g., South Africa, Siberia). The low hydrogen concentration in mantle minerals, together with petrological and geochemical evidence of carbonated silicate melt metasomatism in Dharwar cratonic lithospheric mantle, suggest that these xenoliths are possibly related to proto-kimberlite melts with low water activity prior to being transported to the surface by the Mesoproterozoic Wajrakarur kimberlites. These observations, valid to a depth of ~165-km, suggest that cratonic lithosphere beneath the Dharwar craton may not be particularly indicative of an abnormal hydrogen-rich southern Indian lithosphere in the late Archean and that hydroxylic weakening in olivine would induced a negligible effect on the mantle viscosity of Indian subcontinent.
DS202103-0372
2021
Ghosh, S.Choudhary, S., Sen, K., Kumar, S., Rana, S., Ghosh, S.Forsterite reprecipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic-alkaline-carbonatite complex, Meghalaya, NE India.Geological Magazine, Vol. 158, 3, pp. 475-486.Indiadeposit - Sung Valley

Abstract: Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2-H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2-H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution-precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2-H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.
DS202112-1943
2021
Ghosh, S.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.
DS1982-0221
1982
Ghosh, S.C.Ghosh, S.C., Kundu, U.S.Surface Study of Geological Samples by Scanning Electron Microscope and its Importance in Economic Geology.Indian Minerals, Vol. 36, No. 1, Jan. MAR. PP. 9-17.IndiaDiamonds, Prospecting, Sampling, Analyses, Technique
DS200412-0301
2003
Ghosh, S.K.Chakaborty, C., Mandal, N., Ghosh, S.K.Kinematics of the Gondwana basins of peninsular India.Tectonophysics, Vol. 377, 1, pp. 299-324.IndiaTectonics
DS200712-0714
2006
Ghosh, T.K.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
DS200812-0197
2008
Ghosh, T.K.Chakrabarty, A., Kumar Sen, A., Ghosh, T.K.Amphibole - a key indicator mineral for petrogenesis of the Purulia carbonatite, West Bengal, India.Mineralogy and Petrology, In press available 8p.IndiaCarbonatite
DS1989-0507
1989
Ghosh Roy, A.K.Ghosh Roy, A.K.Investigation for apatite and other associated minerals in the Tamar-Porapahar shear zone in Perulia district and the petrological studies of Association carbonatitesRecords of the Geological Survey of India, extended abstracts of progress, Vol. 122, pt. 3, p. 45IndiaCarbonatite, Apatite
DS1989-0508
1989
Ghosh Roy, A.K.Ghosh Roy, A.K.Study of the carbonatite complex in Ampavalli area near Sunki, Koraputdistrict, and Khariar area in Kalahandidistrict, Orissa with special ref. toR.E.E.Records of the Geological Survey of India, extended abstracts of progress, Vol. 122, pt. 3, p. 47IndiaCarbonatite, rare earth elements (REE).
DS200612-0455
2001
Ghosh Roy, A.K.Ghosh Roy, A.K., Mukhopashyay, P.K., Mallik, A.K.Some alkaline complexes of West Bengal, Orissa and Andhra Pradesh - potential hosts for semi-precious and precious stones.National Seminar on Exploration Survey, Geological Society of India Special Publication, No. 58, pp. 671-676IndiaAlkalic
DS200812-0407
2008
Ghosray, S.Ghosray, S.Repatriation of the Kohinoor diamonds: expanding the legal paradigm for cultural heritage.Fordham International Law Journal, Vol. 31, 3, pp. 741-780.IndiaDiamond notable - legal
DS201604-0626
2016
Ghulam, A.Shavers, E.J., Ghulam, A., Encarnacion, J., Bridges, D.L., Luetemeyer, P.B.Carbonatite associated with the ultramafic diatremes in the Avon volcanic district, Missouri, USA: field, petrographic and geochemical constraints.Lithos, Vol. 248, pp. 506-516.United States, MissouriCarbonatite

Abstract: Here we report field, petrographic, and geochemical analyses of the southeast Missouri Avon Volcanic District intrusive rocks and present the first combined textural and geochemical evidence for the presence of a primary magmatic carbonatite phase among ultramafic dikes, pipes, and diatremes of olivine melilitite, alnöite, and calciocarbonatite. The ?13CVPDB values measured for primary calciocarbonatite as well as carbonates in olivine melilitite and alnöite rocks range from ? 3.8‰ to ? 8.2‰, which are within the typical range of mantle values and are distinct from values of the carbonate country rocks, 0.0‰ to ? 1.3‰. The carbonate oxygen isotope compositions for the intrusive lithologies are in the range of 21.5‰ to 26.2‰ (VSMOW), consistent with post-emplacement low temperature hydrothermal alteration or kinetic fractionation effects associated with decompression and devolatilization. Metasomatized country rock and breccia-contaminated igneous lithologies have carbonate ?13CVPDB values gradational between primary carbonatite values and country rock values. Unaltered sedimentary dolomite breccia and mafic spheroids entrained by calciocarbonatite and the lack of microstratigraphic crystal growth typical of carbonate replacement, also exclude the possibility of hydrothermal replacement as the cause of the magmatic-textured carbonates. Rare earth element (REE) patterns for the alnöite, olivine melilitite, and carbonatite are similar to each other with strong light REE enrichment and heavy REE depletion relative to MORB. These patterns are distinct from those of country rock rhyolite and sedimentary carbonate. These data suggest that rocks of the Avon Volcanic District represent a single ultramafic-carbonatite intrusive complex possibly derived from a single mantle source.
DS201712-2729
2018
Ghulam, A.Shavers, E.J., Ghulam, A., Encarnacion, J.Surface alteration of a melelitite-clan carbonatite and the potential for remote carbonatite detection. AvonOre Geology Reviews, Vol. 92, pp. 19-28.United States, Missouricarbonatite
DS201801-0061
2018
Ghulam, A.Shavers, E.J., Ghulam, A., Encarnacion, J.Surface alteration of a melilitite clan carbonatite and the potential for remote carbonatite detection.Ore Geology Reviews, Vol. 92, pp. 19-28.United States, Missourideposit - Avon

Abstract: The varied lithologic facies and mineralogy resulting from emplacement of syngenetic alkaline, ultramafic and carbonatite (AUC) intrusions are made more diverse by variable weathering and alteration. Ultramafic-carbonatite intrusive complexes are a source for many valuable minerals including diamonds and rare earth element minerals. The intrusive bodies are often difficult to detect in the field due to their paucity, weathering, vegetation, and, in some instances, similarity to country rock, especially in the case of carbonatites among sedimentary carbonates. Remote spectroscopic detection is used extensively for geologic mapping yet has not been applied to differentiating sedimentary and igneous carbonate weathering profiles. Here we document the alteration mineralogy of a newly authenticated melilitite-clan carbonatite occurrence in the Avon Volcanic District in southeast Missouri, USA. The presence of lizardite, vermiculite, phlogopite, and andradite in the weathered crust of calcic and dolomitic carbonatites differentiate them from sedimentary dolomites. We apply field and laboratory spectral measurements to determine the feasibility of humid region AUC remote sensing and classification. Automated humid region detection and classification of carbonatites among sedimentary carbonates is shown to be possible using ratios of absorption features in the 2000-2400?nm range as well as features centered near 680, 900, and 1100?nm due transition metal charge transfer and crystal field splitting in garnet, sheet-silicates, and spinel.
DS201802-0264
2018
Ghulam, A.Shavers, E.J., Ghulam, A., Encaracion, J.Surface alteration of a melilitite clan carbonatite and the potential for remote carbonatite detection.Ore Geology Reviews, Vol. 92, pp. 19-28.United States, Missourideposit - Avon

Abstract: The varied lithologic facies and mineralogy resulting from emplacement of syngenetic alkaline, ultramafic and carbonatite (AUC) intrusions are made more diverse by variable weathering and alteration. Ultramafic-carbonatite intrusive complexes are a source for many valuable minerals including diamonds and rare earth element minerals. The intrusive bodies are often difficult to detect in the field due to their paucity, weathering, vegetation, and, in some instances, similarity to country rock, especially in the case of carbonatites among sedimentary carbonates. Remote spectroscopic detection is used extensively for geologic mapping yet has not been applied to differentiating sedimentary and igneous carbonate weathering profiles. Here we document the alteration mineralogy of a newly authenticated melilitite-clan carbonatite occurrence in the Avon Volcanic District in southeast Missouri, USA. The presence of lizardite, vermiculite, phlogopite, and andradite in the weathered crust of calcic and dolomitic carbonatites differentiate them from sedimentary dolomites. We apply field and laboratory spectral measurements to determine the feasibility of humid region AUC remote sensing and classification. Automated humid region detection and classification of carbonatites among sedimentary carbonates is shown to be possible using ratios of absorption features in the 2000-2400?nm range as well as features centered near 680, 900, and 1100?nm due transition metal charge transfer and crystal field splitting in garnet, sheet-silicates, and spinel.
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
 
 

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