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SDLRC - Scientific Articles all years by Author - Ao-Az


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 - Ao+
Posted/
Published
AuthorTitleSourceRegionKeywords
DS1960-0976
1968
Aoki, K.Kushiro, I., Aoki, K.Origin of Some Eclogite Inclusions in KimberliteAmerican MINERALOGIST., Vol. 53, No. 7-8, PP. 1347-1367.South AfricaMineralogy
DS1970-0471
1972
Aoki, K.Aoki, K., Fodor, K.K., Dowty, E.Tremolite with High Richterite-molecule Content in Kimberlite from Buell Park, Arizona.American MINERALOGIST., Vol. 57, PP. 1889-1893.ArizonaKimberlite, Colorado Plateau, Rocky Mountains
DS1975-0197
1975
Aoki, K.Suwa, K., Aoki, K.Reverse Pleochroism Phlogopite in Kimberlite and Related Rocks from South Africa.Nagoya University Afr. Studies Prelim. Report, PP. 60-64.South AfricaMineralogy
DS1975-0232
1976
Aoki, K.Aoki, K., Fujino, K., Akaogi, M.Titanochondrite and Titanoclinohumite Derived from the Upper Mantle in the Buell Park Kimberlite, Arizona.Contributions to Mineralogy and Petrology, Vol. 56, PP. 243-253.GlobalKimberlite, Colorado Plateau, Rocky Mountains
DS1975-0417
1976
Aoki, K.Smith, D., Aoki, K.Discussion and Reply: Titanochondrodite and Ititanoclino- Chiminite Derived from Upper Mantle in the Buell Park Kimberlite, Arizona.Contributions to Mineralogy and Petrology, Vol. 61, No. 2, PP. 213-215.United States, Arizona, Colorado PlateauBlank
DS1975-0451
1977
Aoki, K.Aoki, K.Titanochrondrite and Titanoclinohumite Derived from the Upper Mantle in the Buell Park Kimberlite, Arizona, United States (us) ( a Reply ).Contributions to Mineralogy and Petrology, Vol. 61, PP. 217-218.GlobalKimberlite, Colorado Plateau, Rocky Mountains
DS1981-0063
1981
Aoki, K.Aoki, K.Chemical Composition of Mafic Ultramafic Xenoliths in the Sullivan Buttes Chino Valley, Arizona.The Science Reports of The Tohoku University, 3rd. Series, M, Vol. 15, Dec. No. 1, PP. 131-135.ArizonaColorado Plateau, Rocky Mountains, Mineral Chemistry, Geochemistry
DS1981-0064
1981
Aoki, K.Aoki, K.Major Element Geochemistry of Chromian Spinel Peridotite Xenoliths in the Green Knobs Kimberlite, New Mexico.The Science Reports of The Tohoku University, 3rd. Series, M, Vol. 15, No. 1, Dec. PP. 127-130.GlobalColorado Plateau, Rocky Mountains, Mineral Chemistry
DS1981-0065
1981
Aoki, K.Aoki, K.Chemical Composition of Garnets in Kimberlites and Their Incorporated Mafic Xenoliths, Colorado Plateau.The Science Reports of The Tohoku University, 3rd. Series, M, Vol. 15, No. 1, Dec. PP. 121-126.GlobalColorado Plateau, Rocky Mountains, Mineral Chemistry, Geochemistry
DS1981-0066
1981
Aoki, K.Aoki, K.Chemical Composition of Potassic Basaltic Rocks from the Colorado Plateau.The Science Reports of The Tohoku University, 3rd. Series, M, Vol. 15, No. 1, PP. 133-135.United States, Colorado PlateauGeochemistry
DS1983-0238
1983
Aoki, K.Fujimaki, H., Tatsumoto, M., Aoki, K.Partition Coefficients of Hafnium, Zirconium and Rare Earth Elements (ree) Phenocrysts and Gro Undmasses.Journal of Geophysical Research, Vol. 89, Feb. 15TH. SUPPL. PP. 662-672.GlobalGeochemistry, Rare Earth Elements (ree), Kimberlite
DS1985-0326
1985
Aoki, K.Kaneoka, I., Takaoka, N., Aoki, K.Possible occurrence of excess 129XE associated with relativelylow40Ar/36Ar ratios in olivine megacryst nodules in South african kimberlitesRock Magnetism and Paleogeophysics, Vol. 12, pp. 89-93South AfricaGeochronology
DS200612-0999
2005
Aoki, K.Ogasawara, Y., Aoki, K.The role of fluid for diamond free UHP dolomitic marble from the Kokchetav Massif.International Geology Review, Vol. 47, 11, pp. 1178-1193.RussiaUHP
DS1970-0870
1974
Aoki, K.I.Aoki, K.I.Phlogopites and Potassic Richterites from Mica Nodules in South African Kimberlites.Contributions to Mineralogy and Petrology, Vol. 48, No. 1, PP. 1-7.South AfricaMineral Chemistry
DS1970-0871
1974
Aoki, K.I.Aoki, K.I.Field Excursion on Kimberlite in South Africa and LesothoJapan. Association Min. Petrol. Economic Geology Journal, Vol. 69, No. 3, PP. 121-127.South Africa, LesothoGuidebook, Geology
DS1975-0015
1975
Aoki, K.I.Aoki, K.I.Origin of Phlogopite and Potassic Richterite Bearing Peridotite Xenoliths from South Africa.Contributions to Mineralogy and Petrology, Vol. 53, No. 3, PP. 145-156.South Africa, LesothoBultfontein, Petrography
DS1975-0121
1975
Aoki, K.I.Kuroda, Y., Suzuoki, T., Matsuo, S., Aoki, K.I.D/h Ratios of the Coexisting Phlogopite Richterite from Mica Nodules and a Peridotite in South African Kimberlites.Contributions to Mineralogy and Petrology, Vol. 52, No. 4, PP. 315-318.South AfricaMineral Chemistry, Hydrogen
DS1975-0542
1977
Aoki, K.I.Kaneoka, I., Takoaoka, N., Aoki, K.I.Rare Gases in a Phlogopite Nodule and a Phlogopite Bearing Pegmatite in South African Kimberlites.Earth and Planetary Science Letters, Vol. 34, No. 1, PP. 181-186.South AfricaMineral Chemistry
DS1975-1093
1979
Aoki, K.I.Kaneoka, I., Aoki, K.I.40 Ar-39 Ar Analyses of Phlogopite Nodules and Phlogopite Bearing Peridotites in South African Kimberlites.Earth and Planetary Science Letters, Vol. 40, PP. 119-129.South AfricaIsotope, Argon, Geochronology
DS1980-0037
1980
Aoki, K.I.Aoki, K.I., Fujimaki, H., Kitamura, M.Exsolved Garnet Bearing Pyroxene Megacrysts from Some South african Kimberlites.Lithos, Vol. 13, PP. 269-279.South AfricaPetrography
DS1984-0110
1984
Aoki, K.I.Aoki, K.I.Petrology of Materials Derived from the Upper MantleIn: Material Science of the Earth's Interior, D. Reidel Publ, pp. 415-444GlobalMantle, Crustal Genesis, Experimental Petrology
DS1984-0111
1984
Aoki, K.I.Aoki, K.I., Fujimaki, H.rare earth elements (REE) ABUNDANCES in EXSOLVED GARNET BEARING CLINOPYROXENE MEGACRYSTS from BELLSBANK KIMBERLITE (SOUTH AFRICA).Chemical Geology, Vol. 45, PP. 165-171.South AfricaSpectrometry, Analyses
DS1985-0021
1985
Aoki, K.I.Aoki, K.I., Yoshida, T., Yusa, K., Nakamura, Y.Petrology and Geochemistry of the Nyamuragira Volcano, ZaireJournal of VOLCANOLOGY, Vol. 25, No. 1-2, JUNE PP. 1-28.Central Africa, ZairePetrology
DS1986-0888
1986
Aoki, K.I.Yoshida, T., Aoki, K.I.Geochemistry of some continental basaltsThe Science reports of the Tohoku University, Third series, Vol. XVI No. 3, Dec. pp. 367-394United StatesMinette, Alkaline rocks
DS201012-0527
2010
Aoki, T.Nakamuta, Y., Toh, S., Aoki, T.Transformation mechanism of graphite to diamonds in ureilites revealed by TEM observation.International Mineralogical Association meeting August Budapest, abstract p. 183.TechnologyUrelilite
DS201612-2324
2014
Aoki, T.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.
DS2001-0038
2001
Aoya, M.Aoya, M.P T D path of eclogite from the Samagawa belt deduced from combination of petrological and microstructural...Journal of Petrology, Vol. 42, No. 7, July, pp. 1225-48.JapanEclogite
DS2002-0053
2002
Aoya, M.Aoya, M., Uehara, S-I., Wallis, S.R.Thermal consequences of a subduction boundary jump: a numerical model for generating subduction related....Tectonics, Vol.21,1, Feb.pp. 17p.MantlePressure temperature paths - clockwise, Subduction - geothermometry
DS2002-0279
2002
Apanasevich, E.A.Chashchin, V.V., Bayanova, T.B.,Apanasevich, E.A.The Monchegorsk ore district as an example of Paleoproterozoic ore bearing chamber structure.Geology of Ore Deposits, Vol.44,2,pp.142-9.Russia, Kola PeninsulaMetallogeny - not specific to diamonds
DS1989-1435
1989
Aparecida Sardela, I.Soubies, F., Melfi, A.J., Aparecida Sardela, I.Zirconium mobility during lateritic weathering of alkaline rocks of Pocosde CaldasXiii International Geochemical Exploration Symposium, Rio 89 Brazilian Geochemical, p. 206. Abstract very briefBrazilAlkaline rocks, Geochemistry
DS200512-0337
2004
Aparicio, A.Gill, R.C., Aparicio, A., El Azzouzi, M., Hernandez, J., Thirlwall, M.F., Bourgois, J., Marriner, G.F.Depleted arc volcanism in the Alboran Sea and shoshonitic volcanism in Morocco: geochemical and isotopic constraints on Neogene tectonic processes.Lithos, Vol. 78, 4, pp. 363-388.Africa, MoroccoShoshonite
DS201803-0474
2017
Apel, D.B.Sepehri, M., Apel, D.B., Hall, R.A.Prediction of mining induced surface subsidence and ground movements at a Canadian diamond mine using electroplastic finite element model. International Journal of Rock Mechanics and Mining Sciences, Vol. 100, pp. 73-82.Canada, Northwest Territoriesdeposit - Diavik
DS200912-0032
2008
Apel, E.Banerjee, P., Burgmann, R., Nagarajan, B., Apel, E.Intraplate deformation of the Indian subcontinent.Geophysical Research Letters, Vol. 35, 18, Sept. 28, L18301IndiaSubduction
DS202011-2028
2020
Apen, F.E.Apen, F.E., Rudnick, R.L., Cottle, J.M., Kylander-Clark, A.R.C., Blondes, M.S., Piccoli, P.M., Seward, G.Four dimensional thermal evolution of the East African Orogen: accessory phase petrochronology of crustal profiles through the Tanzanian Craton and Mozambique belt, northeastern Tanzania.Contributions to Mineralogy and Petrology, Vol. 175, 97, 30p. PdfAfrica, Tanzaniacraton

Abstract: U-Pb petrochronology of deep crustal xenoliths and outcrops across northeastern Tanzania track the thermal evolution of the Mozambique Belt and Tanzanian Craton following the Neoproterozoic East African Orogeny (EAO) and subsequent Neogene rifting. At the craton margin, the upper-middle crust record thermal quiescence since the Archean (2.8-2.5 Ga zircon, rutile, and apatite in granite and amphibolite xenoliths). The lower crust of the craton documents thermal pulses associated with Neoarchean ultra-high temperature metamorphism (ca. 2.64 Ga,?>?900 °C zircon), the EAO (600-500 Ma rutile), and fluid influx during rifting (?650 °C (above Pb closure of rutile and apatite) at the time of eruption. Zoned titanite records growth during cooling of the lower crust at 550 Ma, followed by fluid influx during slow cooling and exhumation (0.1-1 °C/Myr after 450 Ma). Permissible lower-crustal temperatures for the craton and orogen suggest variable mantle heat flow through the crust and reflect differences in mantle lithosphere thickness rather than advective heating from rifting.
DS1960-0010
1960
Apenko, M.A.Apenko, M.A., Matveyeva, G.V., Plotnikova, M.I.Documents on the Study of Diamonds and Diamond Fields of The UssrLeningrad: All Union Geol. Institute Press, Nov. Ser., No. 40.RussiaKimberlite
DS1998-0254
1998
ApexCiezynski, H., Keylor, M., Caro, R., ApexMetallic and industrial mineral assessment report on the Western Block in Fort McMurray/Fort MacKay region.Alberta Geological Survey, MIN 19980004Alberta, northeasternExploration - assessment, Ells River Resources
DS1950-0053
1951
Apfel, E.T.Apfel, E.T., Maynard, J.E., Ploger, L.W.Possible Diatremes in Syracuse, New YorkGeological Society of America (GSA) Bulletin., Vol. 62, P. 1421. (abstract.).United States, Appalachia, New YorkRelated Rocks
DS1992-0037
1992
Aplan, F.F.Aplan, F.F.Mineral process engineering: a historical perspective and predictions For the futureMining Engineering, Vol. 44, No. 8, August pp. 1003-1006GlobalMineral processing, Overview
DS1989-0030
1989
Aplonov, S.V.Aplonov, S.V.The paleogeodynamics of the West Siberian PlatformInternational Geology Review, Vol. 31, No. 9, September pp. 859-867RussiaPlatform, Tectonics, Paleotectonics
DS2002-0054
2002
Apollis, L.Apollis, L., Bluck, B.J., Ward, J.D.The distribution of diamonds on a Late Cenzoic gravel beach, sw Namibia.( Orange River mouth).11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 18.NamibiaGeomorphology, alluvials
DS1991-0026
1991
Apon, W.Apon, W.A new algorithm for coding geological terminologyComputers and Geosciences, Vol. 17, No. 7, pp. 883-894GlobalComputers, Program -coding geological terminology
DS1994-0057
1994
Apparao, A.Apparao, A., Sastry, R.S., Sarma, V.S.Spectral IP studies buried scale models incorporating surface and volumepolarizationExploration Geophysics, Australian Bulletin, Vol. 25, No. 1, March pp. 31-38AustraliaGeophysics -IP, Models
DS2002-0055
2002
Appel, C.Appel, C., Appel, P.W.U., Rollinsonm H.R.Complex chromite textures reveal the history of an early Archean layered ultramafic body in West Greenland.Mineralogical Magazine, Vol.66, 6, pp. 1029-42.GreenlandLayered intrusion
DS1987-0118
1987
Appel, H.Connell, S., Bharythram, K., Appel, H., Sellschop, J.P.F., StemmetResidence sites for F-19 ions implanted into diamondHyperfine Interactions, Vol. 36, No. 3-4, October pp. 185-200GlobalBlank
DS201112-0961
2011
Appel, K.Silversmit, G., Vekemans, B., Appel, K., Schmitz, S., Schoonjans, T., Brenker, F.E., Kaminsky, F., Vincze, L.Three dimensional Fe speciation of an inclusion cloud within an ultradeep diamond by confocal u-x-ray absortion near edge structure: evidence for late stageAnalytical Chemistry, Vol. 83, pp. 6294-6299.South America, Brazil, Mato GrossoJuina, Rio Soriso, diamond overprint
DS1995-1286
1995
Appel, P.Moller, A., Appel, P., Mezgerm K., Schenk, V.Evidence for a 2 Ga subduction zone: eclogites in the Usagaran belt ofTanzaniaGeology, Vol. 23, No. 12, Dec. pp. 1067-1070TanzaniaGeochronology, Subduction, eclogites
DS200712-0944
2007
Appel, P.Schenk, V., Appel, P., Jons, N., Loose, D., Schumann, A., Wegner, H.Pan-African reworking of the northeastern corner of the Congo Craton in Uganda.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 257-258.Africa, UgandaTectonics
DS200712-0945
2007
Appel, P.Schenk, V., Appel, P., Jons, N., Loose, D., Schumann, A., Wegner, H.Pan-African reworking of the northeastern corner of the Congo Craton in Uganda.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 257-258.Africa, UgandaTectonics
DS1997-0039
1997
Appel, P.W.Appel, P.W.High bromine contents and low Chlorine/Bromine ratios in hydrothermally altered komatiitic rocks West Greenland.Precambrian Research, Vol. 82, pp. 177-89.GreenlandUltramafic rocks
DS1990-1350
1990
Appel, P.W.U.Shimizu, H., Umemoto, N., Masuda, A., Appel, P.W.U.Sources of iron formations in the Archean Isua and Malene supracrustalsGeochimica et Cosmochimica Acta, Vol. 54, No. 4, April pp. 1147-1154GreenlandIron formations, Geochronology
DS1994-0058
1994
Appel, P.W.U.Appel, P.W.U.Dispersion patterns of kimberlite indicator mineralsGreenland Geological Survey, OF 94-16, 37p. 7 figs.GreenlandGeochemistry, Diamond, indicators
DS1994-0864
1994
Appel, P.W.U.Kalvig, P., Appel, P.W.U.Greenlandic mineral resources for use in advanced materialsIndustrial Minerals, No. 319, April pp. 45-52.GreenlandCarbonatite
DS2002-0055
2002
Appel, P.W.U.Appel, C., Appel, P.W.U., Rollinsonm H.R.Complex chromite textures reveal the history of an early Archean layered ultramafic body in West Greenland.Mineralogical Magazine, Vol.66, 6, pp. 1029-42.GreenlandLayered intrusion
DS2003-0848
2003
Appel, P.W.U.Lowry, D., Appel, P.W.U., Rollinson, H.R.Oxygen isotopes of an Early Archean layered ultramafic body, southern WestPrecambrian Research, Vol. 126, 3-4, Oct. pp.273-88.GreenlandGeochronology
DS200412-1181
2003
Appel, P.W.U.Lowry, D., Appel, P.W.U., Rollinson, H.R.Oxygen isotopes of an Early Archean layered ultramafic body, southern West Greenland: implications for magma source and post intPrecambrian Research, Vol. 126, 3-4, Oct. pp.273-88.Europe, GreenlandGeochronology
DS201112-0810
2011
Appel, P.W.U.Polat, A., Appel, P.W.U., Fryer, B.J.An overview of the geochemistry of Eoarchean to Mesoarchean ultramafic to mafic volcanic rocks, SW Greenland: implications for mantle depletionGondwana Research, Vol. 20, 2-3, pp. 255-273.MantlePetrogenetic processes at subduction zones Early Earth
DS2003-0975
2003
Appelbe, B.Moresi, L., May, D., Freeman, J., Appelbe, B.Mantle convection modeling with viscoelelastic brittle lithosphere: numerical andLecture notes in Computer Science, No. 2659, pp. 781-87.MantleBlank
DS200412-1367
2003
Appelbe, B.Moresi, L., May, D., Freeman, J., Appelbe, B.Mantle convection modeling with viscoelelastic brittle lithosphere: numerical and computational methodology.Lecture notes in Computer Science, No. 2659, pp. 781-87.MantleLithosphere - model
DS1981-0120
1981
Appelman, D.E.Clarke, R.S., Appelman, D.E., Ross, D.R.An Antarctic iron meteorite contains preterrestrial impact produced diamond and lonsdaleite.Nature, Vol. 291, June 4, pp. 396-8.AntarcticaMeteorite
DS1991-0027
1991
Apperson, K.D.Apperson, K.D.Stress fields of the overriding plate at convergent margins and beneath active volcanic arcs.Science, Vol. 254, Nov. 1, pp. 670-8.GlobalTectonics, plate tectonics, seismic, Asthenosphere, subduction
DS1990-0122
1990
Appiah, H.Appiah, H., Norman, D.I.Origin of diamonds in the Akwatia diamond field, GhanaGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A362GhanaDiamond, Akwatia
DS1993-0036
1993
Appiah, H.Appiah, H. , Norman, D.I., Kuma, J.S., Nartey, R.S., DankwaSource of diamonds in the Bonsa fieldGeological Society Africa and Ghana, Proceedings 9th. International Conference, pp. 78-79.GhanaDiamond, Deposit -Bonsa field
DS1996-0037
1996
Appiah, H.Appiah, H., Norman, D.I., Kuma, J.S.The diamond deposits of GhanaAfrica Geoscience Review, Vol. 3, No. 2, pp. 261-272.GhanaAlluvial diamonds, Deposit -Bonsa, BiriM.
DS200912-0304
2009
Appleby, S.K.Hoal, K., Appleby, S.K., Stammer, J.G.Understanding garnet variability: application of geometallurgy to diamonds and exploration.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyTechnologyGarnet chemistry
DS200912-0305
2009
Appleby, S.K.Hoal, K.O., Appleby, S.K., Stammer, J.G., Palmer, C.SEM based quantitative mineralogical analysis of peridotite, kimberlite and concentrate.Lithos, In press - available 20pAfrica, South Africa, Lesotho, BotswanaDeposit - Premier/Cullinan, Letseng, Ngamiland
DS1950-0311
1957
Appledorn, C.R.Appledorn, C.R.Volcanic Structures in the Chuska Mountains, Navajo Reservation Arizona- New Mexico.Geological Society of America (GSA) Bulletin., Vol. 68, PP. 445-467.United States, Colorado Plateau, Arizona, New MexicoTectonics, Related Rocks
DS1999-0581
1999
Applegate, G.S.Rapp, R.P., Shimizu, N., Applegate, G.S.Reaction between slab derived melts and peridotite in the mantle wedge:experimental constraints at 3.8 GPaChemical Geology, Vol. 160, No. 4, Sept. 2, pp. 335-56.MantlePeridotite - melting, Slab
DS1996-0038
1996
Appleton, J.D.Appleton, J.D., Fuge, R., McCall, G.J.H.Environmental geochemistry and healthGeological Society of London, No. 113, 270pAfricaEnvironment, geochemistry, health, Table of contents
DS1996-0039
1996
Appleton, J.D.Appleton, J.D., McCall, G.J.H.Environmental geochemistry and health with special reference to developingcountriesGeological Society of London, No. 113, 272p. approx. $ 98.00 United StatesGlobalGeochemistry and health, Book -ad
DS201604-0595
2016
Appleton, J.D.Broom-Fendley, S., Styles, M.T., Appleton, J.D., Gunn, G., Wall, F.Evidence for dissolution reprecipitation of apatite and preferential LREE mobility in carbonatite derived late stage hydrothermal processes.American Mineralogist, Vol. 101, pp. 596-611.Africa, MalawiCarbonatite

Abstract: The Tundulu and Kangankunde carbonatite complexes in the Chilwa Alkaline Province, Malawi, contain late-stage, apatite-rich lithologies termed quartz-apatite rocks. Apatite in these rocks can reach up to 90 modal% and displays a distinctive texture of turbid cores and euhedral rims. Previous studies of the paragenesis and rare earth element (REE) content of the apatite suggest that heavy REE (HREE)-enrichment occurred during the late-stages of crystallization. This is a highly unusual occurrence in intrusions that are otherwise light REE (LREE) enriched. In this contribution, the paragenesis and formation of the quartz-apatite rocks from each intrusion is investigated and re-evaluated, supported by new electron microprobe (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) data to better understand the mechanism of HREE enrichment. In contrast to the previous work at Tundulu, we recognize three separate stages of apatite formation, comprising an “original” euhedral apatite, “turbid” apatite, and “overgrowths” of euhedral late apatite. The crystallization of synchysite-(Ce) is interpreted to have occurred subsequent to all phases of apatite crystallization. The REE concentrations and distributions in the different minerals vary, but generally higher REE contents are found in later-stage apatite generations. These generations are also more LREE-enriched, relative to apatite that formed earlier. A similar pattern of increasing LREE-enrichment and increased REE concentrations toward later stages of the paragenetic sequence is observed at Kangankunde, where two generations of apatite are observed, the second showing higher REE concentrations, and relatively higher LREE contents. The changing REE distribution in the apatite, from early to late in the paragenetic sequence, is interpreted to be caused by a combination of dissolution-reprecipitation of the original apatite and the preferential transport of the LREE complexes by F- and Cl-bearing hydrothermal fluids. Successive pulses of these fluids transport the LREE out of the original apatite, preferentially re-precipitating it on the rim. Some LREE remained in solution, precipitating later in the paragenetic sequence, as synchysite-(Ce). The presence of F is supported by the F content of the apatites, and presence of REE-fluorcarbonates. Cl is not detected in the apatite structure, but the role of Cl is suggested from comparison with apatite dissolution experiments, where CaCl2 or NaCl cause the reprecipitation of apatite without associated monazite. This study implies that, despite the typically LREE enriched nature of carbonatites, significant degrees of hydrothermal alteration can lead to certain phases becoming residually enriched in the HREE. Although at Tundulu the LREE-bearing products are re-precipitated relatively close to the REE source, it is possible that extensive hydrothermal activity in other carbonatite complexes could lead to significant, late-stage fractionation of the REE and the formation of HREE minerals.
DS2003-0023
2003
Appleyard, C.M.Appleyard, C.M., Le Roex, A.P., Bell, D.R.The geochemistry of a suite of eclogite xenoliths from the Rietfontein kimberlite, South8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractSouth AfricaEclogites and Diamonds, Deposit - Rietfontein
DS2003-0024
2003
Appleyard, C.M.Appleyard, C.M., Viljoen, K.S., Dobbe, R.A study of eclogitic diamonds and their inclusions from the Finsch kimberlite pipe8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractSouth AfricaEclogites, diamonds, melting, Deposit - Finsch
DS200412-0044
2003
Appleyard, C.M.Appleyard, C.M., Viljoen, K.S., Dobbe, R.A study of eclogitic diamonds and their inclusions from the Finsch kimberlite pipe, South Africa.8 IKC Program, Session 2, AbstractAfrica, South AfricaEclogite, diamonds, melting Deposit - Finsch
DS200412-0045
2004
Appleyard, C.M.Appleyard, C.M., Viljoen, K.S., Dobbe, R.A study of eclogitic diamonds and their inclusions from the Finsch kimberlite pipe, South Africa.Lithos, Vol. 77, 1-4, Sept. pp. 317-332.Africa, South AfricaProterozoic, dodecahedra, deformation, type IaAB, plate
DS200712-0021
2007
Appleyard, C.M.Appleyard, C.M., Bell, D.R., Roex, A.P.Petrology and geochemistry of eclogite xenoliths from the Rietfontein kimberlite, northern Cape, South Africa.Contributions to Mineralogy and Petrology, Vol. 154, 3m pp. 309-333.Africa, South AfricaDeposit - Rietfontein
DS200712-0022
2007
Appleyard, C.M.Appleyard, C.M., Bell, D.R., Roex, A.P.Petrology and geochemistry of eclogite xenoliths from the Rietfontein kimberlite, northern Cape, South Africa.Contributions to Mineralogy and Petrology, Vol. 154, 3, pp. 309-333.Africa, South AfricaRietfontein
DS2000-0025
2000
Appleyard, G.R.Appleyard, G.R., Smith, C.L.Non-resource inputs to estimation of ore reserves - the multiplying factorsMin. Res. Ore Res. Est. AusIMM Guide, Mon. 23, pp. 325-32.AustraliaEconomics - geostatistics, ore reserves, exploration, Not specific to diamonds
DS1970-0022
1970
Applin, K.E.S.Applin, K.E.S.A Review of the South African Alluvial Diamond DepositsSelection Trust Exploration Ltd., IN-HOUSE Report UNPUBL. 14P.South AfricaProspecting, Distribution
DS1970-0472
1972
Applin, K.E.S.Applin, K.E.S.Sampling of Alluvial Diamond Deposits in West AfricaInstitute of Mining and Metallurgy. Transactions, Vol. 81, PP. A62-A67; ALSO: DISCUSSION IN Vol. 82, PP. A32-3West Africa, Sierra LeoneDiamond Mining Recovery, Alluvials, Sampling, Evaluation
DS1975-0233
1976
Applin, K.E.S.Applin, K.E.S.Exploration for Alluvial Diamond DepositsIn: Placer Exploration Mining Conference., PP. 1-21.South Africa, West AfricaSampling, Evaluation
DS200512-0026
2005
Appollonov, V.N.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
DS2003-0025
2003
Appora, I.Appora, I., Eiler, J.M., Matthews, A., Stolper, E.M.Experimental determination of oxygen isotope fractionation between CO2 vapor andGeochimica et Cosmochimica Acta, Vol. 67, 3, pp. 459-71.GlobalMelilite, Melting
DS1986-0137
1986
Aprosinova, N.G.Cherepanov, A.N., Sharapov, V.N., Aprosinova, N.G.The dynamics of magma crystallization in intrusive processesModern Geology, Vol. 10, No. 1, pp. 51-64GlobalBlank
DS1997-0015
1997
Apt, J.Akinin, V.V., Roden, M., Francis, D., Apt, J., Moll-StalcupCompositional and thermal state of the upper mantle beneath the Bering Seabasalt Province: evidence....Canadian Journal of Earth Sciences, Vol. 34, No. 6, June pp. 789-800.RussiaChukchi Peninsula, Basalts
DS1997-0014
1997
Apt, Y.E.Akinin, V.V., Apt, Y.E., Ashchepkov, I.V., Lyapunov, S.The geochemistry of abyssal xenoliths from melanephelinites of northeastRussia.Doklady Academy of Sciences, Vol. 355, No. 5, Jun-July pp. 752-6.RussiaMelanephelinite
DS1998-0036
1998
Apt, Yu.E.Apt, Yu.E., Akinin, V.V., Wright, J.E.Strontium, neodymium, lead isotopes in Neogene melanephelinites and deep seated xenoliths from northeast Russia.Geochemistry International, Vol. 36, No. 1, Jan. pp. 24-33.RussiaXenoliths, Nephelinites
DS200712-0421
2007
Apter, D.Hatton, C., Hill, S., Apter, D., Evans, S., Hatch, D., Hauser, B.Measuring the width of the diamond window by logging the lithosphere with garnet compositions.Diamonds in Kimberley Symposium & Trade Show, Bristow and De Wit held August 23-24, Kimberley, South Africa, GSSA Diamond Workshop CD slides 27Africa, South AfricaGroup I,II kimberlites- plumes, peridotites, eclogites
DS1975-0676
1978
Apter, D.B.Apter, D.B.The nature of ultramafic nodules from the Goedgevinden kimberlite pipe, South fricaBsc. Hons. Rhodes University, Grahamstown, South Africa, South AfricaPetrology
DS1982-0068
1982
Apter, D.B.Apter, D.B., Harper, F.J., Wyatt, B.A.The Geology of the Mayeng Kimberlite SillsProceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 204, (abstract.).South AfricaKimberlite, Mineralogy, Cape Province, Chemistry
DS1984-0112
1984
Apter, D.B.Apter, D.B., Harper, F.J., Wyatt, B.A., Smith, B.H.S.The Geology of the Mayeng Kimberlite Sill Complex, South Africa.Proceedings of Third International Kimberlite Conference, Vol. 1, PP. 43-58.South AfricaMineral Chemistry, Mineralogy, Ventersdorp Lavas, Petrography
DS1992-1420
1992
Apter, D.B.Skinner, E.M.W., Clement, C.R., Gurney, J.J., Apter, D.B., Hatton, C.J.The distribution and tectonic setting of South African kimberlitesRussian Geology and Geophysics, Vol. 33, No. 10, pp. 26-31.South AfricaTectonics, Kimberlite distribution
DS1998-0542
1998
Apter, D.B.Grutter, H.S., Apter, D.B.Garnet xenocryst chemistries in a traverse from Eendekuil to Kimberley over the south western margin ..7th International Kimberlite Conference Abstract, pp. 283-6.South AfricaKaapval Craton, Xenolith geochemistry
DS1998-0543
1998
Apter, D.B.Grutter, H.S., Apter, D.B.Kimberlite and lamproite borne chromite phenocrysts with diamond inclusion type chemistries.7th International Kimberlite Conference Abstract, pp. 280-282.South Africa, BrazilChromite geochemistry, Deposit - Wesselton, Coromandel
DS200412-1845
2003
Apter, D.B.Skinner, E.M.W., Apter, D.B., Morelli, C., Tomlinson, I., Smithson, K.N.Kimberlites of the Man Craton.8 IKC Program, Session 8, POSTER abstractAfrica, Guinea, Sierra Leone, LiberiaDiamond exploration
DS200612-0031
2006
Apter, D.B.Apter, D.B., Hatton, C.Heat flow variations and layered mantle convection.Geochimica et Cosmochimica Acta, Vol. 70, 18, supp. 1, p. 19, abstract only.MantleGeothermometry
DS201505-0247
2015
Apter, D.B.Toledo, V., Apter, D.B., Ward, J.High pressure indicator minerals from the Rakefet magmatic complex ( RMC), Mt. Carmel, Israel.Israel Geological Society, 1p.posterEurope, IsraelMineralogy
DS2003-1288
2003
Apterm D.B.Skinner, E.M.W., Apterm D.B., Morelli, C., Tomlinson, I., Smithson, K.N.Kimberlites of the Man Craton8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractGuinea, Sierra Leone, LiberiaBlank
DS201602-0195
2016
Aquilano, D.Bruno, M., Rubbo, M., Aquilano, D., Massaro, F.R., Nestola, F.Diamond and olivine inclusions: a strange relation revealed by ab initio simulations.Earth and Planetary Science Letters, Vol. 435, 1, pp. 31-35.RussiaDeposit - Udachnaya

Abstract: The study of diamond and its solid inclusions is of paramount importance to acquire direct information on the deepest regions of the Earth. However, although diamond is one of the most studied materials in geology, the diamond-inclusion relationships are not yet understood: do they form simultaneously (syngenesis) or are inclusions pre-existing objects on which diamond nucleated (protogenesis)? Here we report, for the first time, adhesion energies between diamond (D) and forsterite (Fo) to provide a crucial contribution to the syngenesis/protogenesis debate. The following interfaces were investigated at quantum-mechanical level: (i) (001)D/(001)Fo, (ii) (001)D/(021)Fo, and (iii) (111)D/(001)Fo. Our data, along with the ones recently obtained on the (110)D/(101)Fo interface, revealed an unexpected thermodynamic behaviour, all interfaces showing almost equal and low adhesion energies: accordingly, diamond and olivine have an extremely low chemical affinity and cannot develop preferential orientations, even during an eventual epitaxial growth. Combining these results with those of our previous work concerning the morphology constraints of diamond on its inclusions, we can state that the two main arguments used so far in favour of diamond/inclusions syngenesis cannot be longer considered valid, at least for olivine.
DS1993-0037
1993
Aquirre, L.Aquirre, L.Compositional variations of Cretaceous pumpellyites along the western margin of South America and their relation to an extensional geodynamicsettingJournal of Metamorphic Geology, Vol. 11, pp. 437-448Chile, EcuadorAlteration, Tectonics
DS1982-0368
1982
Aquitaine australia minerals ltd., MIMETS EXPLORATION PTY.Lee, R.J., Aquitaine australia minerals ltd., MIMETS EXPLORATION PTY.El 2528 Grass Plains Nt Annual Report 1980-1981Northern Territory Geological Survey Open File Report, No. CR 82/298, 17P.Australia, Northern TerritoryProspecting, Geophysics
DS200512-0245
2005
Araab, E.M.Dostal, J., Keppie, J.D., Hamilton, M.A., Araab, E.M., Lefort, J.P., Murphy, J.B.Crustal xenoliths in Triassic lamprophyre dykes in western Morocco: tectonic implications for the Rheic Ocean suture.Geological Magazine, Vol. 142, 2, pp. 159-172.Africa, MoroccoLamprophyre
DS201908-1768
2019
Arabas, A.Alberti, M., Arabas, A., Fursich, F.T., Andersen, N., Ziolkowski, P.The Middle to Upper Jurassic stable isotope record of Madagascar: linking temperature changes with plate tectonics during the break-up of Gondwana.Gondwana Research, Vol. 73, pp. 1-15.Africa, Madagascargeochemistry

Abstract: Stable isotope (d18O, d13C) analyses were performed on well preserved belemnites, oysters, and rhynchonellid brachiopods from the Middle to Upper Jurassic of the Morondava Basin in southern Madagascar. Both brachiopods and oysters indicate similar average temperatures of 18.7 to 19.3?°C in the Early Callovian, followed by a temperature decrease towards the Middle Oxfordian (13.9?°C) and a minimum in the Early Kimmeridgian (12.3?°C). In contrast, belemnites from the Oxfordian show lower average temperatures of 10.0?°C, which is likely caused by specific conditions for these organisms (e.g., different fractionation or life habits). Additionally, three oysters from the Upper Oxfordian and Lower Kimmeridgian were used for high-resolution stable isotope analyses. The data show seasonal fluctuations of >6?°C around averages between 14.4 and 14.7?°C. Latitudinal temperature gradients for the Callovian and Kimmeridgian are similar to today at the examined low latitudes of the southern hemisphere. The observed cooling of around 5?°C from the Callovian to the Oxfordian/Kimmeridgian can be attributed to a concurrent southward drift of Madagascar during the break-up of Gondwana. Thus, the study underlines the importance of considering palaeogeography in interpreting stable isotope data as well as the potential of detecting and timing palaeogeographic events by using stable isotope analyses.
DS1996-0040
1996
Arad, V.Arad, V.Current bibliography of Middle East GeologyAfrican Geoscience Review, Vol. 3, No. 2, pp. 343-354GlobalLebanon, Red Sea, Syria, Turkey, Bibliography
DS200812-0040
2008
Arafin, S.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
DS1995-0053
1995
Aragon, E.Aragon, E.Crystallization in a saturated magma Pt. 1: theory- three phase segregation laws and saturated magma -model.Neues Jahrb. Mineralogie, Vol. 170, No. 1, pp. 75-?MantleMagma, Geochemistry -trace elements
DS1975-1131
1979
Aragon, R.Mccallister, R.N., Meyer, H.O.A., Aragon, R.Partial Thermal History of Two Exsolved Clinopyroxenes From the Thaba Putsoa Kimberlite Pipe, Lesotho.Proceedings of Second International Kimberlite Conference, Proceedings Vol. 2, PP. 244-248.LesothoGeothermometry
DS2002-1757
2002
AraiYamamoto, J., Kagi, H., Kaneoka, Lai, Prikhodko,AraiFossil pressures of fluid inclusions in mantle xenoliths exhibiting rheology of mantle minerals...Earth and Planetary Science Letters, Vol.198,3-4,pp.511-19., Vol.198,3-4,pp.511-19.MantleSpectroscopy, Geobarometry - mantle minerals
DS2002-1758
2002
AraiYamamoto, J., Kagi, H., Kaneoka, Lai, Prikhodko,AraiFossil pressures of fluid inclusions in mantle xenoliths exhibiting rheology of mantle minerals...Earth and Planetary Science Letters, Vol.198,3-4,pp.511-19., Vol.198,3-4,pp.511-19.MantleSpectroscopy, Geobarometry - mantle minerals
DS201012-0113
2010
Arai, H.Collerson, K.D., Williams, Q., Kamber, B.S., Omori, S., Arai, H., Ohtani, E.Majoritic garnet: a new approach to pressure estimation of shock events in meteorites and the encapsulation of sub-lithospheric inclusions in diamonds.Geochimica et Cosmochimica Acta, Vol. 74, 20, pp. 5939-5937.TechnologyMeteorite
DS1984-0113
1984
Arai, S.Arai, S.Pressure Temperature Dependent Compositional Variation of Phlogopitic Micas in Upper Mantle Peridotites.Contributions to Mineralogy and Petrology, Vol. 87, PP. 260-264.GlobalGarnet, Spinel, Kimberlite, Thermobarometry, Analytical
DS1984-0114
1984
Arai, S.Arai, S.Igneous Mineral equilibration temperatures in Some Alpine Type Peridotites in JapanTerra Sci. Publishing Materials science of the earth's interior, pp. 445-460JapanPeridotite, Petrology
DS1986-0024
1986
Arai, S.Arai, S.Potassium and Sodium variation in phlogopite and amphibole of upper mantle peridotites due to fractionation of the metasomatizing fluidsJournal of Petrology, Vol. 27, No. 3, May pp. 436-444GlobalMantle, Potassium, Sodium, Analyses
DS1986-0025
1986
Arai, S.Arai, S.Iron meteorite paragenesis, a new group of mineral inclusions in diamondNeues Jahrbuch fnr Mineralogie, Vol. H 10, pp. 463-466Sierra LeoneMeteorite, morphology, diamond inclusions, Diamond
DS1987-0012
1987
Arai, S.Arai, S.An estimation of the least depleted spinel peridotite on the basis of olivine spinel mantle arrayNeues Jahrbuch fnr Mineralogie Monats, No. 8, August pp. 347-354GlobalBlank
DS1988-0721
1988
Arai, S.Uto, K., Hirai, H., Goto, K., Arai, S.K-Ar ages of carbonate and mantle nodule bearing lamprophyre dikes fromShingu, central Shikoku, southwest JapanGeochemical JOurnal, Vol. 21, No. 6, pp. 283-290JapanBlank
DS1990-0123
1990
Arai, S.Arai, S.Characterization of spinel peridotites in terms of olivine-spinel mantlearrayTerra, Abstracts of International Workshop Orogenic Lherzolites and Mantle Processes, Vol. 2, December abstracts p. 125South AfricaPeridotites, Mantle
DS1991-0028
1991
Arai, S.Arai, S., Okada, H.Petrology of serpentine sandstone as a key to tectonic development of serpentine beltsTectonophysics, Vol. 195, pp. 65-81JapanPeridotite -general serpentine belts, Tectonics, Petrology
DS1992-0038
1992
Arai, S.Arai, S.Chemistry of chromian spinel in volcanic rocks as a potential guide to magma chemistryMineralogical Magazine, Vol. 56, pp. 173-184MantleMagma chemistry, Volcanics
DS1994-0059
1994
Arai, S.Arai, S.Characterization of spinel peridotites by olivine-spinel compositionalrelationships: review and interpretation.Chemical Geology, Vol. 113, pp. 191-204.JapanPeridotites, Petrology
DS1994-0060
1994
Arai, S.Arai, S.Characterization of spinel peridotites by olivine spinel compositional relationships -review and interpretation.Chemical Geology, Vol. 113, No. 3-4, Apr. 1, pp. 191-204.MantlePeridotites
DS1995-0054
1995
Arai, S.Arai, S., Abe, N.Reaction of orthopyroxene in peridotite xenoliths with alkali-basalt melt and its implication for alpine crAmerican Mineralogist, Vol. 80, No. 9-10, Sept, Oct pp. 1041-1047.JapanXenoliths
DS1998-0004
1998
Arai, S.Abe, N., Arai, S., Yurimoto, H.Petrology of the arc peridotite xenoliths: implications for geochemical evolution of the wedge mantle.7th International Kimberlite Conference Abstract, pp. 4-6.MantleXenoliths, Subduction
DS1998-0037
1998
Arai, S.Arai, S., Matsukage, K.Petrology of chromitite micropod Hess Deep: comparison between abyssal -alpine type podiform chromititesLithos, Vol. 43, No. 1, May pp. 1-14GlobalMagma, mantle, supra-subduction
DS2000-0004
2000
Arai, S.Abe, N., Arai, S., Shcheka, S., Yurimoto, H.Petrology of harzburgite and related xenoliths from Avacha volcano, Kamchatka Arc and its implication for..Igc 30th. Brasil, Aug. abstract only 1p.RussiaMantle - wedge mantle processes, Xenoliths
DS2001-0039
2001
Arai, S.Arai, S., Kida, M., Abe, M., Yurimoto, H.Petrology of peridotite xenoliths in alkali basalt ( 11 Ma) from Boun, Korea: insight into upper mantle....Journal of Min. Petrol. Sciences, Vol. 96, No. 3, pp. 89-99.GlobalMantle mineralogy - East Asian continental margin
DS2001-0562
2001
Arai, S.Kadoshima, K., Arai, S.Chemical analysis of detrital chromian spinels from the Lizard area: an attempt for lithological and petrologyNeues Jahrbuch fnr Mineralogie, No. 5, pp. 193-205.GlobalPeridotites
DS2001-0739
2001
Arai, S.Matsumoto, I., Arai, S.Morphological and chemical variations of chromian spinel in dunite harzburgite complexes from Sangun ZoneMineralogy and Petrology, Vol. 73, No. 4, pp. 305-24.JapanMantle melt reaction, Chromitite formation - not specific to diamonds
DS2001-0802
2001
Arai, S.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
DS200412-1436
2004
Arai, S.Nishio, Y., Nakai, S., Yamamoto, J., Sumino, H., Matsumoto, T., Prikhodko, V.S., Arai, S.Lithium isotopic systematics of the mantle derived ultramafic xenoliths: implications for EMI origin.Earth and Planetary Science Letters, Vol. 217, 3, Jan. 15, pp. 245-261.MantleGeochronology
DS200412-2165
2004
Arai, S.Yamamoto, J., Kaneoka, I., Nakai, S., Kagi, H., Prikhodko, V.S., Arai, S.Evidence for subduction related components in the subcontinental mantle from low 3He/4He and 40Ar/36Ar ratio in mantle xenolithsChemical Geology, Vol. 207, 3-4, July 16, pp. 237-259.RussiaGeochemistry - noble gases, subduction, lherzolite
DS200612-0880
2006
Arai, S.Matsumoto, T., Maruoka, T., Matsuda, J-I., Shimoda, G., Yamamoto, K., Morishita, T., Arai, S.Isotopic compositions of noble gas and carbon in the Archean carbonatites from the Sillinjarvi mine, central Finland.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 21, abstract only.Europe, FinlandCarbonatite, geochronology
DS200612-1122
2006
Arai, S.Rajesh, V.J., Arai, S.Baddelyite apatite spinel phlogopite (BASP) rock in Achankovil shear zone, South India, as a probable cumulate from melts of carbonatite affinity.Lithos, Vol.90, 1-2, August pp. 1-18.IndiaCarbonatite
DS200712-0008
2007
Arai, S.Ali, M., Arai, S.Clinopyroxene rich lherzolite xenoliths from Bir Ali, Yemen possible product of peridotite/melt reactions.Journal of Mineralogical and Petrological Sciences, Vol. 102, 2, pp. 137-142.MantleLherzolite
DS200712-0023
2007
Arai, S.Arai, S., Abe, N., Ishimaru, S.Mantle peridotites from the Western Pacific.Gondwana Research, Vol. 11, 1-2, Jan. pp. 180-199.AsiaPeridotite
DS200712-0863
2007
Arai, S.Python, M., Ceuleneer, G., Ishida, Y., Barrat, J-A., Arai, S.Oman diopsidites: a new lithology diagnostic of very high temperature hydrothermal circulation in mantle peridotite below oceanic spreading centres.Earth and Planetary Science Letters, Vol. 255, 3-4, March 30, pp. 289-305.Europe, OmanPeridotite
DS200712-0864
2007
Arai, S.Python, M., Ishida, Y., Ceuleneer, G., Arai, S.Trace element heterogeneity in hydrothermal diopside: evidence for Ti depletion and Sr Eu LREE enrichment during hydrothermal metamorphism of mantle harzburgite.Journal of Mineralogical and Petrological Sciences, Vol. 102, 2, pp. 143-149.MantleHarzburgite
DS200812-0041
2008
Arai, S.Arai, S., Ishimaru, S.Insights into petrological characteristics of the lithosphere of mantle wedge beneath arcs through peridotite xenoliths: a review.Journal of Petrology, Vol. 49, 4, pp. 665-695.MantleXenoliths - peridotite
DS200812-0509
2008
Arai, S.Ishimaru, S., Arai, S.Nickel enrichment in mantle olivine beneath a volcanic front.Contributions to Mineralogy and Petrology, Vol. 156, 1, pp. 119-131.MantleNickel
DS200912-0831
2009
Arai, S.Yamamoto, J.,Nakai, S., Nishimura, K., Kaneoka, I., Sato, K., Okumura, T., Prikhodko,V.S., Arai, S.Intergranular trace elements in mantle xenoliths from Russian Far East: example for mantle metasomatism by hydrous melt.Island Arc, Vol. 18, 1, pp. 225-241.RussiaMetasomatism
DS201012-0608
2010
Arai, S.Rajesh, V.J., Arai, S., Santosh, M., Tamura, A.LREE rich hibonite in ultrapotassic rocks in southern India.Lithos, Available in press formated 11p.IndiaAlkalic
DS201112-0024
2011
Arai, S.Arai, S., Ahmed, A.H., Miura, M.Ultrahigh pressure podiform chromitites as a possible deep recycled material.Goldschmidt Conference 2011, abstract p.447.Asia, Tibet, OmanUHP
DS201112-0025
2011
Arai, S.Arai, S., Okamura, H., Kadoshima, K., Tanaka, C., Suzuki, K., Ishimaru, S.Chemical characteristics of chromian spinel in plutonic rocks: implications for deep magma processes and discrimination of tectonic setting.Island Arc, Vol. 20, 1, pp. 125-137.MantleMagmatism - tectonics
DS201611-2096
2016
Arai, S.Arai, S., Miura, M.Formation and modification of chromitites in the mantle.Lithos, Vol. 264, pp. 277-295.MantlePodiform, UHP, melt

Abstract: Chromitites (aggregates of chromite or chromian spinel) inform us of various mantle processes, including magmatism, magma/peridotite reaction and mantle dynamics [1]. They typically form as magmatic cumulates from chromiteoversaturated melt within conduits in the mantle peridotite [2]. They are usually enveloped by replacive dunite [1]. In Oman, both concordant and discordant chromitites are of low-P (upper mantle) magmatic origin [3, 4]. Their chromite grains contain inclusions of pargasite, aspidolite and pyroxenes, which suggest low P. Mineral chemistry suggests involvement of MORB for the concordant chromitite, and of arc-related magma for the discrodant one. This is consistent with the switch of tectonic setting, from MOR to SSZ, for the Oman ophiolite magmatism. Only the concordant chromitite shows metamorphic characters, i.e. exsolution of diopside in chromite and outward diffusion of Ni (< 30 cm) in the dunite envelope [5], indicating its longer residence in the mantle. Ultra-high pressure (UHP) chromitites have been reported from the Tibetan and Polar Ural ophiolites [6, 7]. Most of their petrographic characteristics can be explained by UHP "metamorphism" of low-P magmatic chromitites above [8]. This may suggest recycling of low-P chromitite as deep as the transion-zone mantle [9]. The UHP chromitite is, however, still highly enigmatic: some characteristics, e.g., the amount and origin of carbon as diamond, are difficult to explain. High-T aqueous fluids containing Cl, S and C, can mobilize Cr and precipitate chromite in the mantle [10]. Chromite was dissolved and precipitated in/from high-T fluids which formed diopsidites in Oman. Chromite was concentrated to form thin "hydrothermal chromitite". Sub-arc metasomatized peridotites contain secondary chromite closely associated with fluid inclusions, indicating Cr mobility via fluids within the mantle wedge. Hydrothermal chromitites are expected in the mantle where fluid circulation is available.
DS201703-0408
2017
Arai, S.Ikenne, M., Souhassou, M., Arai, S., Soulaimani, A.A historical overview of Moroccan magmatic events along the northwest edge of the West African craton.Journal of African Earth Sciences, Vol. 127, pp. 3-15.Africa, MoroccoCraton - magmatism

Abstract: Located along the northwestern edge of the West African Craton, Morocco exhibits a wide variety of magmatic events from Archean to Quaternary. The oldest magmatic rocks belong to the Archean Reguibat Shield outcrops in the Moroccan Sahara. Paleoproterozoic magmatism, known as the Anti-Atlas granitoids, is related to the Eburnean orogeny and initial cratonization of the WAC. Mesoproterozoic magmatism is represented by a small number of mafic dykes known henceforth as the Taghdout mafic volcanism. Massive Neoproterozoic magmatic activity, related to the Pan-African cycle, consists of rift-related Tonian magmatism associated with the Rodinia breakup, an Early Cryogenian convergent margin event (760-700 Ma), syn-collisional Bou-Azzer magmatism (680-640 Ma), followed by widespread Ediacaran magmatism (620-555 Ma). Each magmatic episode corresponded to a different geodynamic environment and produced different types of magma. Phanerozoic magmatism began with Early Cambrian basaltic (rift?) volcanism, which persisted during the Middle Cambrian, and into the Early Ordovician. This was succeeded by massive Late Devonian and Carboniferous, pre-Variscan tholeiitic and calc-alkaline (Central Morocco) volcanic flows in basins of the Moroccan Meseta. North of the Atlas Paleozoic Transform Zone, the Late Carboniferous Variscan event was accompanied by the emplacement of 330-300 Ma calc-alkaline granitoids in upper crustal shear zones. Post-Variscan alkaline magmatism was associated with the opening of the Permian basins. Mesozoic magmatism began with the huge volumes of magma emplaced around 200 Ma in the Central Atlantic Magmatic Province (CAMP) which was associated with the fragmentation of Pangea and the subsequent rifting of Central Atlantic. CAMP volcanism occurs in all structural domains of Morocco, from the Anti-Atlas to the External Rif domain with a peak activity around 199 Ma. A second Mesozoic magmatic event is represented by mafic lava flows and gabbroic intrusions in the Internal Maghrebian flysch nappes as well as in the external Mesorif. This event consists of Middle-Upper Jurassic MORB tholeiites emplaced during opening of the Alpine Tethys ocean. The Central High Atlas also records Early Cretaceous alpine Tethys magmatism associated with the aborted Atlas rift, or perhaps linked to plume activity on the edge of the WAC. Cenozoic magmatism is associated with Tertiary and Quaternary circum-Mediterranean alkaline provinces, and is characterized by an intermittent activity over 50 Ma from the Anti-Atlas to the Rif Mountain along a SW-NE volcanic lineament which underlines a thinned continental lithosphere.
DS201710-2270
2017
Arai, S.Umino, S., Knayama, K., Kitamura, K., Tamura, A., Ishizuka, A., Senda, R., Arai, S.Did boninite originate from the heterogeneous mantle with reycled ancient slab?Island Arc, Sept. 28, 3p.Mantlesubduction

Abstract: Boninites are widely distributed along the western margin of the Pacific Plate extruded during the incipient stage of the subduction zone development in the early Paleogene period. This paper discusses the genetic relationships of boninite and antecedent protoarc basalt magmas and demonstrates their recycled ancient slab origin based on the T-P conditions and Pb-Hf-Nd-Os isotopic modeling. Primitive melt inclusions in chrome spinel from Ogasawara and Guam islands show severely depleted high-SiO2, MgO (high-silica) and less depleted low-SiO2, MgO (low-silica and ultralow-silica) boninitic compositions. The genetic conditions of 1?346?°C at 0.58?GPa and 1?292?°C at 0.69?GPa for the low- and ultralow-silica boninite magmas lie on adiabatic melting paths of depleted mid-ocean ridge basalt mantle with a potential temperature of 1?430?°C in Ogasawara and of 1?370?°C in Guam, respectively. This is consistent with the model that the low- and ultralow-silica boninites were produced by remelting of the residue of the protoarc basalt during the forearc spreading immediately following the subduction initiation. In contrast, the genetic conditions of 1?428?°C and 0.96?GPa for the high-silica boninite magma is reconciled with the ascent of more depleted harzburgitic source which pre-existed below the Izu-Ogasawara-Mariana forearc region before the subduction started. Mixing calculations based on the Pb-Nd-Hf isotopic data for the Mariana protoarc basalt and boninites support the above remelting model for the (ultra)low-silica boninite and the discrete harzburgite source for the high-silica boninite. Yb-Os isotopic modeling of the high-Si boninite source indicates 18-30?wt% melting of the primitive upper mantle at 1.5-1.7?Ga, whereas the source mantle of the protoarc basalt, the residue of which became the source of the (ultra)low-Si boninite, experienced only 3.5-4.0?wt% melt depletion at 3.6-3.1?Ga, much earlier than the average depleted mid-ocean ridge basalt mantle with similar degrees of melt depletion at 2.6-2.2?Ga.
DS201803-0457
2017
Arai, S.Khedr, M.Z., Arai, S.Peridotite chromitite complexes in the eastern Desert of Egypt: insight into Neoproterozoic sub arc mantle processes.Gondwana Research, Vol. 52, pp. 59-70.Africa, Egyptchromitites

Abstract: The Neoproterozoic peridotite-chromitite complexes in the Central Eastern Desert of Egypt, being a part of the Arabian-Nubian Shield, are outcropped along the E-W trend from Wadi Sayfayn, Wadi Bardah, and Jabal Al-Faliq to Wadi Al-Barramiyah, from east to west. Their peridotites are completely serpentinized, and the abundance of bastite after orthopyroxene suggests harzburgite protoliths with subordinate dunites, confirmed by low contents of Al2O3, CaO and clinopyroxene (< 3 vol%) in bulk peridotites. The primary olivine is Fo89.3-Fo92.6, and the residual clinopyroxene (Cpx) in serpentinites contains, on average, 1.1 wt% Al2O3, 0.7 wt% Cr2O3, and 0.2 wt% Na2O, similar in chemistry to that in Izu-Bonin-Marian forearc peridotites. The wide range of spinel Cr-number [Cr/(Cr + Al)], 0.41-0.80, with low TiO2 (0.03 wt%), MnO (0. 3 wt%) and YFe [(Fe3 +/(Cr + Al + Fe3 +) = 0.03 on average)] for the investigated harzburgites-dunites is similar to spinel compositions for arc-related peridotites. The partial melting degrees of Bardah and Sayfayn harzburgites range mainly from 20 to 25% and 25 to 30% melting, respectively; this is confirmed by whole-rock chemistry and Cpx HREE modelling (~ 20% melting). The Barramiyah peridotite protoliths are refractory residues after a wide range of partial melting, 25-40%, where more hydrous fluids are available from the subducting slab. The Neoproterozoic mantle heterogeneity is possibly ascribed mainly to the wide variations of partial melting degrees in small-scale areas, slab-derived inputs and primordial mantle compositions. The Sayfayn chromitites were possibly crystallized from island-arc basaltic melts, followed by crystallization of Barramiyah chromitites from boninitic melt in the late stage of subduction. The residual Cpx with a spoon-shape REE pattern is rich in both LREE and fluid-mobile elements (e.g., Pb, B, Li, Ba, Sr), but poor in HFSE (e.g., Ta, Nb, Zr, Th), similar to Cpx in supra-subduction zone (SSZ) settings, where slab-fluid metasomatism is a prevalent agent. The studied chromitites and their host peridotites represent a fragment of sub-arc mantle, and originated in an arc-related setting. The systematic increase in the volume of chromitite pods with the increasing of their host-peridotite thickness from Northern to Southern Eastern Desert suggests that the thickness of wall rocks is one factor controlling the chromitite size. The factors controlling the size of Neoproterozoic chromitite pods are the thickness, beside the composition, of the host refractory peridotites, compositions and volumes of the supplied magmas, the amount of slab-derived fluids, and possibly the partial melting degree of the host peridotites.
DS202007-1120
2020
Arai, S.Abe, N., Surour, A.A., Madani, A.A., Arai, S.Metasomatized peridotite xenoliths from the Cretaceous rift related Natash volcanics and their bearing on the nature of the lithospheric mantle beneath the southern part of the eastern desert of Egypt.Lithos, in press available , 47p. PdfAfrica, Asia, Egyptperidotites

Abstract: Highly carbonated mantle xenoliths have been found in rift-related alkaline basalts at the Wadi Natash area in the southern part of the Eastern Desert of Egypt. Although all olivine and most orthopyroxene was replaced by carbonate and/or quartz, textural and mineral chemical features show that they are plagioclase-free spinel peridotites (lherzolite to harzburgite). Cr and Mg numbers (Cr#, Mg#) of Cr-spinel vary from 0.06 to 0.45 and 0.73 to 0.81, respectively. The correlation between Cr# and Mg# of the Cr-spinel in the studied xenoliths is weakly negative and its TiO2 content is slightly higher than in abyssal peridotite that was not affected by melt injection. The chemistry of ortho- and clinopyroxene suggests enstatite and chromian diopside compositions, respectively, with distinct signatures of a sub-continental mantle source. In particular, the Na2O contents (>1.0?wt%) and AlVI/AlIV ratios (1.2-2.6) of chromian diopside suggest such an origin. Two-pyroxene geothermometry indicates a temperature of about 900?°C, which is slightly lower than that of ordinary spinel peridotite xenoliths from other rift zones. It is evident that the studied peridotite xenoliths had experienced mantle processes (e.g. decompression melting, magma upwelling and metasomatism) at higher pressure than abyssal peridotites. The trace-element chemistry of clinopyroxene, e.g. high LREE/HREE ratios {(Ce/Yb)n?=?7}, high LREE contents (>3.6?ppm and up to 30.0?ppm Ce) and high Sr between >85.6?ppm and 466?ppm, indicates metasomatic alteration of the peridotite. Clinopyroxene in one sample has very low Ti/Eu and high LREE/HREE ratios. Clinopyroxene with (Ce/Yb)n higher than 3-4 and Ti/Eu ratio lower than 1500 may have experienced carbonatite or carbonate-rich melt metasomatism prior to their incorporation into the host basalt. The basalt itself is almost devoid of any carbonatization and hence the studied mantle peridotites were carbonatized before the generation of the basaltic magma but following an earlier event of K-metasomatism as indicated by the presence of phlogopite. The studied peridotites from the Wadi Natash area were altered by a carbonate-rich melt during a rifting stage. The results of the present paper indicate that the Natash basalts with their peridotite xenoliths extruded along transversal fractures of the NW-trending Nuqra-Kom Ombo-Kharit continental rift on its western shoulder in the south Eastern Desert of Egypt.
DS202008-1428
2020
Arai, S.Nishiyama, T., Ohfuji, H., Fukuba, K., Terauchi, M., Nishi, U., Harada, K., Unoki, K., Moribe, Y., Yoshiasa, A., Ishimaru, S., Mori, Y., Shigeno, M., Arai, S.Microdiamond in a low grade metapelite from a Cretaceous subduction complex, western Kyushu, Japan. ( UHP) Nishisonogi unitNature Scientific Reports, Vol. 10, 11645 11p. PdfAsia, Japanmicrodiamond

Abstract: Microdiamonds in metamorphic rocks are a signature of ultrahigh-pressure (UHP) metamorphism that occurs mostly at continental collision zones. Most UHP minerals, except coesite and microdiamond, have been partially or completely retrogressed during exhumation; therefore, the discovery of coesite and microdiamond is crucial to identify UHP metamorphism and to understand the tectonic history of metamorphic rocks. Microdiamonds typically occur as inclusions in minerals such as garnet. Here we report the discovery of microdiamond aggregates in the matrix of a metapelite from the Nishisonogi unit, Nagasaki Metamorphic Complex, western Kyushu, Japan. The Nishisonogi unit represents a Cretaceous subduction complex which has been considered as an epidote-blueschist subfacies metamorphic unit, and the metapelite is a member of a serpentinite mélange in the Nishisonogi unit. The temperature condition for the Nishisonogi unit is 450 °C, based on the Raman micro-spectroscopy of graphite. The coexistence of microdiamond and Mg-carbonates suggests the precipitation of microdiamond from C-O-H fluid under pressures higher than 2.8 GPa. This is the first report of metamorphic microdiamond from Japan, which reveals the hidden UHP history of the Nishisonogi unit. The tectonic evolution of Kyushu in the Japanese Archipelago should be reconsidered based on this finding.
DS201908-1791
2019
Arai, T.Masuda, K., Arai, T., Takahashi, M.Effects of frictional properties of quartz and feldspar in the crust on the depth extent of the seismogenic zone. ** not specific to diamondProgress in Earth and Planetary Science, doi.org/10.1186 /s40645-019-0299-5Mantlegeophysics - seismic

Abstract: The depth extent of the crustal seismogenic zone is closely related to the size of earthquakes. The mechanisms that control the depth of the lower transition of the seismogenic zone are important issues in seismology and disaster mitigation. Laboratory studies have shown that the mechanism of earthquake nucleation is controlled by the frictional properties of fault materials. We measured the velocity dependences of the steady-state friction of quartz and feldspar, two major components of crustal rocks, under dry and wet conditions at temperatures up to 600?°C. In the presence of water, the temperature range over which the velocity dependence of steady-state friction was negative was wider for feldspar than for quartz, thus indicating that the temperature range of earthquake nucleation is wider for feldspar than for quartz. Considering that temperature increases with depth, our findings indicate that the material properties of feldspar likely play a dominant role in limiting the depth extent of the seismogenic zone.
DS201212-0017
2012
Arajo, D.P.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
DS201112-1098
2011
ArajuoWalter, 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
DS201312-0024
2013
Arajuo, D.P.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
DS200912-0545
2009
Arakawa, M.Odake, S., Kagi, H., Arakawa, M., Ohta, A., Harte, B.Oxidation state of chromium in ferropericlese inclusions in lower mantle diamonds determined with micro-XANES measurements.Goldschmidt Conference 2009, p. A962 Abstract.MantleDiamond inclusions
DS200912-0544
2009
Arakawa, S.Odake, S., Fukura, S., Arakawa, S., Ohta, M., Harte, B., Kagi, H.Divalent chromium in ferropericlase inclusions in lower mantle diamonds revealed by morco XANES measurements.Journal of Mineralogical and Petrological Sciences, Vol. 103, 5, pp. 350-353.TechnologyDiamond inclusions
DS1989-0921
1989
Arakeliants, M.M.Makhotkin, I.L., Arakeliants, M.M., Vladykin, N.V.On the age of lamproites from the Aldanian province. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 306, No. 3, pp. 703-707RussiaLamproite, Geochronology
DS1990-0975
1990
Arakelyants, M.M.Makhotkin, I.L., Arakelyants, M.M., Vladykin, N.V.Age of lamproites of the Aldan provinceDoklady Academy of Sciences USSR, Earth Sci. Section, Vol. 306, No. 3, pp. 163-167RussiaLamproites, Geochronology
DS1992-0039
1992
Aral, I.Aral, I., et al.Ultra high pressure metamorphic rocks from the Dobie Shen, ChinaProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 2, abstract p. 601ChinaEclogites, Metamorphic rocks
DS201704-0618
2017
Aramastsev, A.A.Aramastsev, A.A., Vesolovskiy, R.V., Travin, A.V., Yudin, D.S.Paleozoic tholeiitic magmatism of the Kola Peninsula: spatial distribution, age, and relation to alkaline magmatism.Petrology, Vol. 25, 1, pp. 42-65.Russia, Kola PeninsulaMagmatism - alkaline

Abstract: This paper focuses on the occurrences of tholeiitic magmatism in the northeastern Fennoscandian shield. It was found that numerous dolerite dikes of the Pechenga, Barents Sea, and Eastern Kola swarms were formed 380-390 Ma ago, i.e., directly before the main stage of the Paleozoic alkaline magmatism of the Kola province. The isotope geochemical characteristics of the dolerites suggest that their primary melts were derived from the mantle under the conditions of the spinel lherzolite facies. The depleted mantle material from which the tholeiites were derived shows no evidence for metasomatism and enrichment in high fieldstrength and rare earth elements, whereas melanephelinite melts postdating the tholeiites were generated in an enriched source. It was shown that the relatively short stage of mantle metasomatism directly after the emplacement of tholeiitic magmas was accompanied by significant mantle fertilization. In contrast to other large igneous provinces, where pulsed intrusion of large volumes of tholeiitic magmas coinciding or alternating with phases of alkaline magmatism was documented, the Kola province is characterized by systematic evolution of the Paleozoic plume-lithosphere process with monotonous deepening of the level of magma generation, development of mantle metasomatism and accompanying fertilization of mantle materials, and systematic changes in the composition of melts reaching the surface.
DS1991-0029
1991
Arana, V.Arana, V., Ortiz, R.The Canary Islands: tectonics, magmatism and geodynamic frameworkMagmatism in Extensional structural settings, Springer pp. 209-249.GlobalTectonics, Alkaline rocks
DS1989-0031
1989
Aranda-Gomez, J.J.Aranda-Gomez, J.J., Luhr, J.F., Pier, J.G.Petrology and geochemistry of basanitic rocks from the la Brena and ElJagury Maar complex, Durango, MexicoGeological Society of America (GSA) Annual Meeting Abstracts, Vol. 21, No. 6, p. A201. AbstractMexicoBasanite, Petrology
DS1990-0590
1990
Araneda, M.Gotze, H-J., Lahmeyer, B., Schmidt, S., Strunk, S., Araneda, M.Central Andes gravity dat a baseEos, Vol. 71, No. 16, April 17, pp. 401, 406-407Andes, Chile, ArgentinaGeophysics- gravity, Database
DS201412-0473
2014
Aranovich, L.Korikovsky, S., Kotov, A., Salnikova, E., Aranovich, L., Korpechkov, D., Yakovleva, S., Tolmacheva, E., Anisimova, I.The age of the protolith of metamorphic rocks in the southeastern Lapland granulite belt, southern Kola Peninsula: correlation with the Belomorian mobile belt in the context of the problem of Archean eclogites.Petrology, Vol. 22, 2, pp. 91-108.Russia, Kola PeninsulaEclogite
DS201412-0599
2013
Aranovich, L.Moulas, E., Podladchikov, Y., Aranovich, L., Kostopoulos, D.The problem of depth in geology: when pressure does not translate into depth.Petrology, Vol. 21, 6, pp. 527-538.MantleDynamics
DS202011-2050
2020
Aranovich, L. Ya.Limanov, E.V., Butvina, V.G., Safonov, O.G., Van, K.V., Aranovich, L. Ya.Phlogopite formation in the orthopyroxene-garnet system in the presence of H2O-KCL fluid to the processes of mantle metasomatism.Doklady Earth Sciences, Vol. 494, 1, pp. 713-717.Russiametasomatism

Abstract: The results of experimental studies are presented for reactions in the orthopyroxene-garnet-phlogopite system in the presence of H2O-KCl fluid at 3-5 GPa and 900-1000°C, which model the processes of phlogopite formation in garnet peridotites and pyroxenites during alkaline metasomatism of the upper mantle. The experiments demonstrated regular variations in the composition of garnet, pyroxenes, and phlogopite depending on the KCl content of the fluid. With increasing KCl content of the fluid, enstatite and garnet become unstable, the Al2O3 content of enstatite decreases, and the amount of grossular and knorringite components in garnet are maximum at a KCl content of ~10 mol %. Our results illustrate well the regular variations in the compositions of the coexisting minerals and their zoning in phlogopite-bearing peridotites of the lithospheric mantle.
DS1987-0013
1987
Aranovich, L.Y.Aranovich, L.Y., Kosyakov, N.A.Garnet orthopyroxene geothermobarometer thermodynamics and examples ofapplication. (Russian)Geochemistry International (Geokhimiya) (Russian), Vol. 10, October pp. 1363-1377RussiaBlank
DS201512-1935
2015
Araoka, D.Kon, Y., Araoka, D., Ejima, T., Hirata, T.Rapid and precise determination of major and trace elements in CCRMP and USGS geochemical reference samples using femtosecond laser ablation ICP-MS.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 245-250.TechnologyCarbonatite

Abstract: We measured 10 major (SiO2, TiO2, Al2O3, total Fe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5) and 32 trace (Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Pb, Th, and U) elements in 16 geochemical reference samples (AGV-1, AGV-2, BCR-1, BCR- 2, BHVO-2, BIR-1a, DNC-1a, G-2, GSP-1, GSP-2, MAG-1, QLO-1, RGM-1, RGM-2, SGR-1b, and STM-1) distributed by United States Geological Survey (USGS) and three reference rock samples (SY-2, SY-3, and MRG-1) provided by Canadian Certifi ed Reference Materials Project (CCRMP) using inductively coupled plasma -mass spectrometry coupled with the femtosecond laser ablation sample introduction technique (fsLA-ICP-MS). Before the elemental analysis, fused glassbeads were prepared from the mixture of sample powder and high-purity alkali fl ux with a mixing ratio of 1:10. The abundances of the major and trace elements were externally calibrated by using glass beads containing the major and trace elements prepared from 17 Geological Survey of Japan (GSJ) geochemical reference samples (JB-1, JB-1a, JB-2, JB-3, JA-1, JA-2, JA-3, JR-1, JR-2, JR-3, JP-1, JGb-1, JGb-2, JG-1a, JG- 2, JG-3, and JSy-1). Typical analysis repeatabilities for these geochemical reference samples were better than 3% for Al2O3 and Na2O; <5% for SiO2, TiO2, total Fe2O3, MnO, MgO, CaO, K2O, P2O5, Zn, Rb, Sr, Zr, Nb, Ba, Nd, and U; <8% for Sc, V, Cr, Co, Y, Cs, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Pb, and Th; <11% for Ni and Cu. These data clearly demonstrate that high analytical repeatability can be achieved by the fsLA-ICP-MS technique with glass beads made from 0.5 g larger samples.
DS201911-2507
2019
Araoka, D.Akam, C., Simandl, G.J., Lett, R., Paradis, S., Hoshino, M., Kon, Y., Araoka, D., Green, C., Kodama, S., Takagi, T., Chaudhry, M.Comparison of methods for the geochemical determination of rare earth elements: Rock Canyon Creek REE-F-Ba deposit case study, SE British Columbia, Canada.Geochemistry: Exploration, Environment, Analysis, Vol. 19, pp. 414-430.Canada, British Columbiageochemistry

Abstract: Using Rock Canyon Creek REE-F-Ba deposit as an example, we demonstrate the need for verifying inherited geochemical data. Inherited La, Ce, Nd, and Sm data obtained by pressed pellet XRF, and La and Y data obtained by aqua regia digestion ICP-AES for 300 drill-core samples analysed in 2009 were compared to sample subsets reanalysed using lithium metaborate-tetraborate (LMB) fusion ICP-MS, Na2O2 fusion ICP-MS, and LMB fusion-XRF. We determine that LMB ICP-MS and Na2O2 ICP-MS accurately determined REE concentrations in SY-2 and SY-4, and provided precision within 10%. Fusion-XRF was precise for La and Nd at concentrations exceeding ten times the lower detection limit; however, accuracy was not established because REE concentrations in SY-4 were below the lower detection limit. Analysis of the sample subset revealed substantial discrepancies for Ce concentrations determined by pressed pellet XRF in comparison to other methods due to Ba interference. Samarium, present in lower concentrations than other REE compared, was underestimated by XRF methods relative to ICP-MS methods. This may be due to Sm concentrations approaching the lower detection limits of XRF methods, elemental interference, or inadequate background corrections. Aqua regia dissolution ICP-AES results, reporting for La and Y, are underestimated relative to other methods.
DS1984-0569
1984
Arase, T.Osugi, S., Arase, T., Hara, K., Amita, F.Diamond Formation in Molten Nickel. (research Note)High Temperatures-high Pressures, Vol. 16, No. 2, PP. 191-195.GlobalExperimental Petrology
DS2000-0027
2000
AraujoArchanjo, C.J., Trinidade, R.I., Macedo, AraujoMagnetic fabric of a basaltic dyke swarm associated with Mesozoic rifting in northeastern Brasil.Journal of South American Earth Sciences, Vol. 13, No. 3, July pp. 179-89.BrazilDike swarms, tectonics, Geophysics - magnetics
DS201112-1156
2011
AraujoZedgenizov, D.A., Ragozin, Shatsky, Kagi, Odake, Griffin, Araujo, YuryevaEvidence for evolution of growth media in superdeep diamonds from Sao-Luis Brazil.Goldschmidt Conference 2011, abstract p.2244.South America, BrazilCl imaging
DS1998-0038
1998
Araujo, A.L.N.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
DS2001-0040
2001
Araujo, A.L.N.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
DS2003-0444
2003
Araujo, A.L.N.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
DS200412-0612
2003
Araujo, A.L.N.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
DS200912-0356
2009
Araujo, D.Kaminsky, F.V., Khachatryan, G.K., Andreazza, P., Araujo, D., Griffin, W.L.Super deep diamonds from kimberlites in the Juin a area, Mato Grosso State, Brazil.Lithos, Vol. 1125, pp. 833-842.South America, Brazil, Mato GrossoDiamond inclusions
DS200912-0849
2009
Araujo, D.Zedgenizov, D.A., Ragozin, A.L., Shjatsky, V.S., Araujo, D., Griffin, W.L., Kagi, H.Mg and Fe rich carbonate silicate high density fluids in cuboid diamonds from the Internationalnaya kimberlite pipe. Yakutia.Lithos, In press availableRussia, YakutiaDeposit - International
DS201012-0617
2010
Araujo, D.Rege, S., Griffin, W.L., Pearson, A.J., Araujo, D., Zedgenizov, D., O'Reilly, S.Y.Trace element patterns of fibrous and monocrystalline diamonds: insights into mantle fluids.Lithos, Vol. 118, pp. 313-337.TechnologyDiamond genesis, morphology
DS201112-0026
2010
Araujo, D.Araujo, D., Ribeiro, D., Bulanonva, G., Smith, C., Walter, M., Kohn, S.Diamond inclusions from the Juina-5 kimberlite, Brazil.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 43.South America, Brazil, Mato GrossoDiamond inclusions
DS201112-0533
2011
Araujo, D.Kohn, S.C., Walter, M.J., Araujo, D., Bulanova, G.P., Smith, C.B.Subducted oceanic crust exhumed from the lower mantle.Goldschmidt Conference 2011, abstract p.1213.South America, BrazilJuina diamonds
DS201212-0728
2012
Araujo, D.Thomson, A.R., Walter, M.J., Kohn, S.C., Russell, B.C., Bulanova, G.P., Araujo, D., Smith, C.B.Evidence for the role of carbonate melts in the origin of superdeep diamond inclusions from the Juina-5 kimberlite, Brazil.Goldschmidt Conference 2012, abstract 1p.South America, BrazilDeposit - Juina-5
DS201412-0930
2014
Araujo, D.Thomson, A.R., Kohn, S.C., Bulanova, G.P., Smith, C.B., Araujo, D., Walter, M.J.Origin of sub-lithopheric diamonds from the Juina-5 kimberlite ( Brazil): constraints from carbon isotopes and inclusion compositions.Contributions to Mineralogy and Petrology, Vol. 168, pp. 1081-1091.South America, BrazilDeposit - Juina-5
DS201502-0113
2014
Araujo, D.Thomson, A.R., Kohn, S.C., Bulanova, G.P., Smith, C.B., Araujo, D., EMIF, Walter, M.J.Origin of sub-lithospheric diamonds from the Juina-5 kimberlite ( Brazil): constraints from carbon isotopes and inclusion compositions.Contributions to Mineralogy and Petrology, Vol. 168, pp. 1081-1110.South America, BrazilDeposit - Juina-5
DS201610-1913
2016
Araujo, D.Thomson, A.R., Kohn, S.C., Bulanova, G.P., Smith, C.B., Araujo, D., Walter, M.J.Trace element composition of silicate inclusions in sub-lithospheric diamonds from the Juina-5 kimberlite: evidence for diamond growth from slab melts.Lithos, in press available 17p.South America, BrazilDeposit - Juina-5

Abstract: The trace element compositions of inclusions in sub-lithospheric diamonds from the Juina-5 kimberlite, Brazil, are presented. Literature data for mineral/melt partition coefficients were collated, refitted and employed to interpret inclusion compositions. As part of this process an updated empirical model for predicting the partitioning behaviour of trivalent cations for garnet-melt equilibrium calibrated using data from 73 garnet-melt pairs is presented. High levels of trace element enrichment in inclusions interpreted as former calcium silicate perovskite and majoritic garnet preclude their origin as fragments of an ambient deep mantle assemblage. Inclusions believed to represent former bridgmanite minerals also display a modest degree of enrichment relative to mantle phases. The trace element compositions of ‘NAL’ and ‘CF phase’ minerals are also reported. Negative Eu, Ce, and Y/Ho anomalies alongside depletions of Sr, Hf and Zr in many inclusions are suggestive of formation from a low-degree carbonatitic melt of subducted oceanic crust. Observed enrichments in garnet and ‘calcium perovskite’ inclusions limit depths of melting to less than ~ 600 km, prior to calcium perovskite saturation in subducting assemblages. Less enriched inclusions in sub-lithospheric diamonds from other global localities may represent deeper diamond formation. Modelled source rock compositions that are capable of producing melts in equilibrium with Juina-5 ‘calcium perovskite’ and majorite inclusions are consistent with subducted MORB. Global majorite inclusion compositions suggest a common process is responsible for the formation of many superdeep diamonds, irrespective of geographic locality. Global transition zone inclusion compositions are reproduced by fractional crystallisation from a single parent melt, suggesting that they record the crystallisation sequence and melt evolution during this interaction of slab melts with ambient mantle. All observations are consistent with the previous hypothesis that many superdeep diamonds are created as slab-derived carbonatites interact with peridotitic mantle in the transition zone.
DS1995-0592
1995
Araujo, D.P.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
DS1998-0039
1998
Araujo, D.P.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
DS1998-0477
1998
Araujo, D.P.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
DS1998-0522
1998
Araujo, D.P.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
DS2003-0026
2003
Araujo, D.P.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
DS200912-0007
2009
Araujo, D.P.Araujo, D.P., Griffin, W.L., O'Reilly, S.Y.Mantle melts, metasomatism and diamond formation: insights from melt inclusions in xenoliths from Diavik, Slave Craton.Lithos, In press available, 34p.Canada, Northwest TerritoriesDeposit - Diavik
DS200912-0008
2009
Araujo, D.P.Araujo, D.P., Griffin, W.L., O'Reilly, S.Y., Grant, K.J., Ireland, T., Van Achterbergh, E.Micro inclusions in monocrystalline octahedral diamonds and coated diamonds from Diavik, Slave Craton: clues to diamond genesis.Lithos, In press available 38p.Canada, Northwest TerritoriesDeposit - Diavik
DS201212-0018
2012
Araujo, D.P.Araujo, D.P., Silveira, F.V., Weska, R.K., Rachid, F., Neto, F.E.B., Ireland, T., Holden, P., Gobbo, L.Diamonds from the Sao Francisco and Amazon cratons, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Andari, Lencois, Barra do Mendes, Catalao, Frutal
DS201212-0019
2012
Araujo, D.P.Araujo, D.P., Weska, R.K., Correa, R.S., Valadao, L.V., Kuberek, N.T., Suvorova, L.F.The kimberlite Juina-5 Brazil: textural and xenocryst chemistry.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Juina-5
DS201212-0139
2012
Araujo, D.P.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
DS201212-0656
2012
Araujo, D.P.Silveira, F.V., Britto, R.S., Matos, L., Araujo, D.P.Diamante Brasil project.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Coromandel, Diamantina
DS201212-0770
2012
Araujo, D.P.Weska, R.K., Brod, J.A., Dantas, E.L., Araujo, D.P.Mineral chemistry of garnets and ilmenites of the Pepper-1 and Cosmos-3 intrusions, Espigao D'Oeste, Rondonia, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, Brazil, RondoniaDeposit - Pepper, Cosmos
DS201610-1846
2016
Araujo, D.P.Borges, M.P.A.C., Moura, M.A., Lenharo, S.L.R., Smith, C.B., Araujo, D.P.Mineralogical characaterization of diamonds from Roosevelt Indigenous Reserve, Brazil, using non-destructive methods. Lithos, in press available 17p.South America, Brazil, RondoniaDeposit - Igarape Lajes Diggings

Abstract: In this study, 660 diamonds from Igarapé Lajes Diggings (Roosevelt and Aripuanã Park indigenous areas), in Amazonian craton, Rondônia State, Brazil, were investigated. Their morphological, optical and surface characteristics were described using optical and scanning electron microscopy (SEM), cathodoluminescence (CL) and infrared spectroscopy (FTIR). The results demonstrated a predominance of resorbed crystals with many surface corrosion features, generally colorless, and led to the identification of four distinct groups: G1, G2, G3 and G4. Group G1 presents features of secondary sources while G2 and G4 show only primary features, some of which are not described in literature. Group G3 is similar to the other groups, however, is composed of less resorbed specimens with primary octahedral morphology relatively well preserved, indicating shorter time of exposure to dissolution effects. Cathodoluminescence in G2 is attributed to features of plastic deformation and to low contents of nitrogen (< 100 ppm, Type II) and high aggregation (IaB). G4 shows homogeneous blue CL, high contents of nitrogen (700 to 1000 ppm) and intermediate aggregation (IaAB). G1 presents luminescence influenced by radiation effects and populations with N contents and aggregation in the same ranges of G2 and G4, suggesting that the primary sources of the three groups can be the same. The relationship of nitrogen content versus aggregation state indicates higher temperatures of formation for G2 and lower for G4. The obtained data suggests that diamonds of G2 originated in sublithospheric mantle as has also been reported in nearby deposits (Machado River and Juína). The employed techniques were also effective in distinguishing diamonds from Roosevelt Reserve and from other localities, indicating that they could be used for improvement of certification procedures of diamonds of unknown origin.
DS201902-0306
2018
Araujo de Azevedo, P.Peres Rocha, M., Assumpcao, M., Fuck, R., Araujo de Azevedo, P., Penna, Crepaldi Affonso, G.M., Sousa Lima Costa, I., Farrapo Albuquetque, D.Llithosphere expression of the boundary between the Amazonian and extra-Amazonian domains of the South American platform from travel time seismic tomography.Researchgate, AGU 1p. Preprint pdfSouth Americacraton

Abstract: The South American platform is the stable part of the South American plate, unaffected by the orogenesis of the Andes and the Caribbean. Its basement is composed of Archean and Proterozoic cratonic blocks amalgamated by mobile belts, and can be separated in two large domains or continental masses: 1) The Amazonian, Northwest-west portion, including the Amazonian craton, related to the Laurentia supercontinent; and 2) the extra-Amazonian, Central-southeast or Brasiliano domain, related to West Gondwana, formed of several paleocontinental fragments, where the São Francisco and Rio de La Plata cratons and the Paranapanema block are the largest. It has been suggested that these two domains are separated by the Transbrasiliano Lineament to the south and the Araguaia Fold Belt to the north. Teleseismic P waves from 4,989 earthquakes recorded by 339 stations operated mainly in Brazil in the last 25 years have been used for relative-time tomography. The Amazonian domain is predominantly characterized by higher velocities. The SW (extra-Amazonian) domain is characterized by several blocks with high velocities, such as in and around the Sao Francisco Craton, and the Paranapanema block. Results of P-wave travel time tomography allowed to observe a strong low-velocity anomaly near 100-200 km depth following the Araguaia-Paraguay fold belt. This strong low-velocity anomaly could be considered the limit between these two domains, reaching lithospheric depths, and does not necessarily follow the Transbrasiliano lineament, especially in its southern portion.
DS201503-0133
2015
Araujo e Azevedo, P.Araujo e Azevedo, P., Peres Rocha, M., Pereira Soares, J.E., Fuck, R.A.Thin lithosphere beween the Amazonian and Sao Francisco cratons, in central Brazil, revealed by seismic P wave tomography.Geophysical Journal International, Vol. 201, 1, pp. 61-69.South America, BrazilGeophysics - seismic

Abstract: Results of P-wave traveltime seismic tomography in central Brazil unravel the upper-mantle velocity structure and its relationship with the tectonic framework. Data were recorded between 2008 and 2012 at 16 stations distributed over the study area, and were added to the database used by Rocha et al. to improve the resolution of anomalies, and to image the surrounding regions. The main objective was to observe the upper-mantle boundary zone between the Amazonian and São Francisco cratons, represented by mobile belts, inside the Tocantins Province, and to study the lithosphere related to the collision between these two cratons during the Neoproterozoic. A set of low-velocity anomalies was observed crossing the study area in the NE–SW direction, in agreement with the main trend of the Transbrasiliano lineament. The region where the anomalies are located was interpreted as the zone separating the Amazonian and São Franciscan palaeoplates. There is a good correlation between the low-velocity anomalies and the high seismicity of this region, suggesting that it is a region of weakness, probably related to lithospheric thinning. High velocities were observed under the Amazonian and São Francisco cratons. A model is proposed for the lithospheric subsurface in central Brazil, emphasizing the boundary zone between the main palaeoplates in the study area. After merging both databases, the low-velocity anomalies in the central part of the study area suggest tectonic partitioning of the lithosphere. Synthetic tests show that the tomography results are robust.
DS200912-0341
2009
AravanisJones, 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
DS201610-1840
2016
Aravanis, T.Aravanis, T., Chen, J., Fuechsle, M., Grujic, M., Johnston, P., Kok, Y., Magaraggia, R., Mann, A., Mann, L., McIntoshm S., Rheinberger, G., Saxey, D., Smalley, M., van Kann, F., Walker, G., Winterflood, J.VK1 tm - a next generation airborne gravity gradiometer.ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 5p.TechnologyGradiometer

Abstract: The minerals exploration industry’s demand for a highly precise airborne gravity gradiometer has driven development of the VK1TM Airborne Gravity Gradiometer, a collaborative effort by Rio Tinto and the University of Western Australia. VK1TM aims to provide gravity gradient data with lower uncertainty and higher spatial resolution than current commercial systems. In the recent years of VK1TM development, there have been significant improvements in hardware, signal processing and data processing which have combined to result in a complete AGG system that is approaching competitive survey-ready status. This paper focuses on recent improvements. Milestone-achieving data from recent lab-based and moving-platform trials will be presented and discussed, along with details of some advanced data processing techniques that are required to make the most use of the data.
DS1994-1551
1994
Aravena, R.Schubert, C., Fritz, P., Aravena, R.Late Quaternary Paleoenvironmental studies in the Gran Sabana (Venezuelan Guyana shield).Quat. International, Vol. 21, pp. 81-90.VenezuelaGeomorphology, Gran Sabana
DS2000-0026
2000
Arazamastev, A.A.Arazamastev, A.A., Glaznev, V.N., Raevsky, A.B., et al.Morphology and internal structure of the Kola alkaline province, northeast Fennoscandian Shield: 3D density modelingJournal of Asian Earth Science, Vol. 18, No.2, Apr. pp.213-28.Russia, Kola, FennoscandiaGeophysics - density, structure, tectonics, Kola alkaline province
DS201112-0027
2011
Arazamastev, A.A.Arazamastev, A.A., Khachai, Yu.V.Paleozoic alkaline volcanism of the northeastern Fennoscandia: geochemical features and petrologic consequences.Deep Seated Magmatism, its sources and plumes, Ed. Vladykin, N.V., pp. 96-125.Europe, Fennoscandia, Kola PeninsulaLovozero, Khibina, Kontosero
DS1990-0124
1990
Arbogast, B.F.Arbogast, B.F.Quality assurance manual for the Branch of geochemistry... United States Geological Survey (USGS)United States Geological Survey (USGS) Open File, No. 90-0668, 184pUnited StatesGeochemistry, Sample procedures
DS200512-1077
2005
Arboleya, M-L.Teixell, A., Ayarza, F., Zeyen, H., Fernandez, M., Arboleya, M-L.Effects of mantle upwelling in a compressional setting: the Atlas Mountains of Morocco.Terra Nova, Vol. 17, 5. pp. 456-461.Africa, MoroccoPlume
DS1986-0610
1986
Arbunies, M.Nogues-Carulla, J.M., Vendrell-Saz, M., Arbunies, M., Lopez-SolerPhotometric study of UV-luminescence of cut diamonds,and its relationship with their colour classificationFourteenth General Meeting of IMA., p. 187. (abstract.)GlobalDiamond morphology, UV-luminescence
DS200512-0027
2005
Arcay, D.Arcay, D., Tric, E., Doin, M-P.Numerical simulations of subduction zones: effect of slab dehydration on the mantle wedge dynamics.Physics of the Earth and Planetary Interiors, Vol. 149, 1-2, March 15, pp. 133-153.MantleSubduction
DS200512-0254
2005
Arcay, D.Dumoulin, C., Doin, M-P, Arcay, D., Fleitout, L.Onset of small scale instabilities at the base of the lithosphere: scaling laws and role of pre-existing lithospheric structures.Geophysical Journal International, Vol. 160, 1, pp. 345-357.MantleGeophysics - seismics
DS200612-0032
2006
Arcay, D.Arcay, D., Doin, M-P., Tric, E., Bousquet, R.D.Overriding plate thinning in subduction zones: localized convection induced by slab dehydration.Geochemistry, Geophysics, Geosystems: G3, Vol. 7, Q02007MantleGeothermometry, hydrated slab-derived water fluxes
DS200612-0157
2006
Arcay, D.Bousquet, R., De Capitani, C., Arcay, D.Feedback of the metamorphic changes on the subducting processes.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleSubduction
DS200712-0024
2007
Arcay, D.Arcay, D., Doin, M-P., Tric, E., Bousquet, R.D.Influence of the precollisional stage on subduction dynamics and the buried crust thermal state: insights from numerical simulations.Tectonophysics, Vol. 441, pp. 27-45.MantleSubduction
DS200712-0025
2007
Arcay, D.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
DS200712-0026
2007
Arcay, D.Arcay, D., Tric, E., Doin, M-P.Slab surface temperature in subduction zones: influence of the interplate decoupling depth and upper plate thinning process.Earth and Planetary Science Letters, Vol. 255, 3-4, March 30, pp. 324-338.MantleSubduction
DS201602-0187
2015
Arcay, D.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.
DS201709-1953
2017
Arcay, D.Arcay, D.Modeling the interplate domain in thermo-mechanical simulations of subduction: critical effects of resolution and rheology, and consequences on wet mantle melting.Physics of the Earth and Planetary Interiors, Vol. 269, 1, pp. 112-132.Mantlesubduction

Abstract: The present study aims at better deciphering the different mechanisms involved in the functioning of the subduction interplate. A 2D thermo-mechanical model is used to simulate a subduction channel, made of oceanic crust, free to evolve. Convergence at constant rate is imposed under a 100 km thick upper plate. Pseudo-brittle and non-Newtonian behaviours are modelled. The influence of the subduction channel strength, parameterized by the difference in activation energy between crust and mantle (?Ea) is investigated to examine in detail the variations in depth of the subduction plane down-dip extent, zcoup . First, simulations show that numerical resolution may be responsible for an artificial and significant shallowing of zcoup if the weak crustal layer is not correctly resolved. Second, if the age of the subducting plate is 100 Myr, subduction occurs for any ?Ea . The stiffer the crust is, that is, the lower ?Ea is, the shallower zcoup is (60 km depth if ?Ea = 20 kJ/mol) and the hotter the fore-arc base is. Conversely, imposing a very weak subduction channel (?Ea > 135 J/mol) leads there to an extreme mantle wedge cooling and inhibits mantle melting in wet conditions. Partial kinematic coupling at the fore-arc base occurs if ?Ea = 145 kJ/mol. If the incoming plate is 20 Myr old, subduction can occur under the conditions that the crust is either stiff and denser than the mantle, or weak and buoyant. In the latter condition, cold crust plumes rise from the subduction channel and ascend through the upper lithosphere, triggering (1) partial kinematic coupling under the fore-arc, (2) fore-arc lithosphere cooling, and (3) partial or complete hindrance of wet mantle melting. zcoup then ranges from 50 to more than 250 km depth and is time-dependent if crust plumes form. Finally, subduction plane dynamics is intimately linked to the regime of subduction-induced corner flow. Two different intervals of ?Ea are underlined: 80-120 kJ/mol to reproduce the range of slab surface temperature inferred from geothermometry, and 10-40 kJ/mol to reproduce the shallow hot mantle wedge core inferred from conditions of last equilibration of near-primary arc magmas and seismic tomographies. Therefore, an extra process controlling mantle wedge dynamics is needed to satisfy simultaneously the aforementioned observations. A mantle viscosity reduction, by a factor 4-20, caused by metasomatism in the mantle wedge is proposed. From these results, I conclude that the subduction channel down-dip extent, zcoup , should depend on the subduction setting, to be consistent with the observed variability of sub-arc depths of the subducting plate surface.
DS201810-2293
2017
Arcay, D.Arcay, D.Modelling the interplate domain in thermo-mechanical simulations of subduction: critical effects of resolution and rheology, and consequences on wet mantle melting.Physics of the Earth and Planetary Interiors, Vol. 269, 1, pp. 112-132.Mantlesubduction

Abstract: The present study aims at better deciphering the different mechanisms involved in the functioning of the subduction interplate. A 2D thermo-mechanical model is used to simulate a subduction channel, made of oceanic crust, free to evolve. Convergence at constant rate is imposed under a 100 km thick upper plate. Pseudo-brittle and non-Newtonian behaviours are modelled. The influence of the subduction channel strength, parameterized by the difference in activation energy between crust and mantle () is investigated to examine in detail the variations in depth of the subduction plane down-dip extent, . First, simulations show that numerical resolution may be responsible for an artificial and significant shallowing of if the weak crustal layer is not correctly resolved. Second, if the age of the subducting plate is 100 Myr, subduction occurs for any . The stiffer the crust is, that is, the lower is, the shallower is (60 km depth if kJ/mol) and the hotter the fore-arc base is. Conversely, imposing a very weak subduction channel ( J/mol) leads there to an extreme mantle wedge cooling and inhibits mantle melting in wet conditions. Partial kinematic coupling at the fore-arc base occurs if kJ/mol. If the incoming plate is 20 Myr old, subduction can occur under the conditions that the crust is either stiff and denser than the mantle, or weak and buoyant. In the latter condition, cold crust plumes rise from the subduction channel and ascend through the upper lithosphere, triggering (1) partial kinematic coupling under the fore-arc, (2) fore-arc lithosphere cooling, and (3) partial or complete hindrance of wet mantle melting. then ranges from 50 to more than 250 km depth and is time-dependent if crust plumes form. Finally, subduction plane dynamics is intimately linked to the regime of subduction-induced corner flow. Two different intervals of are underlined: 80-120 kJ/mol to reproduce the range of slab surface temperature inferred from geothermometry, and 10-40 kJ/mol to reproduce the shallow hot mantle wedge core inferred from conditions of last equilibration of near-primary arc magmas and seismic tomographies. Therefore, an extra process controlling mantle wedge dynamics is needed to satisfy simultaneously the aforementioned observations. A mantle viscosity reduction, by a factor 4-20, caused by metasomatism in the mantle wedge is proposed. From these results, I conclude that the subduction channel down-dip extent, , should depend on the subduction setting, to be consistent with the observed variability of sub-arc depths of the subducting plate surface.
DS201502-0082
2014
Arce Santana, E.Moreno Chavez, G., Sarocchi, D., Arce Santana, E., Borselli, L.Using Kinect to analyze pebble to block-sized clasts in sedimentology.Computers & Geosciences, Vol. 72, pp. 18-32.TechnologyNot specific to diamonds
DS1999-0016
1999
Archambeau, Ch. B.Archambeau, Ch. B.Studies of three dimensional lithospheric structure and tectonics using seismic tomographic methods.. applic.Global Tectonics and Met., Vol. 7, No. 1, Feb. pp. 5-6.MantleLithosphere, Geophysics - seismics
DS1991-0311
1991
Archanjo, C.Corsini, M., Vauchez, A., Archanjo, C., De Sa, E.F.J.Strain transfer at continental scale from a transcurrent shear zone to a transpressional fold belt: the Patos-Serido system, northeastern BrasilGeology, Vol. 19, No. 6, June pp. 586-589BrazilStructure -shear zone, Brasiliano-pan-African Orogeny
DS1994-1304
1994
Archanjo, C.J.Olivier, Ph., Archanjo, C.J.Magnetic and magmatic structures of the Emas granodioritic pluton(Cachoeirinha belt). Relationships with Pan-African strike slip fault systemTectonophysics, Vol. 229, pp. 239-250BrazilStructure -fault systems, Cachoeirinha belt
DS1995-0249
1995
Archanjo, C.J.Caby, R., Arthaud, M.H., Archanjo, C.J.Lithostratigraphy and petrostructural characterization of supracrustal units in the Brasiliano belt of BrasilJournal of South American Earth Sciences, Vol. 8, No. 3-4, pp. 235-246BrazilStratigraphy, Petrology
DS2000-0027
2000
Archanjo, C.J.Archanjo, C.J., Trinidade, R.I., Macedo, AraujoMagnetic fabric of a basaltic dyke swarm associated with Mesozoic rifting in northeastern Brasil.Journal of South American Earth Sciences, Vol. 13, No. 3, July pp. 179-89.BrazilDike swarms, tectonics, Geophysics - magnetics
DS2002-0056
2002
Archanjo, C.J.Archanjo, C.J., Trindade, R.I.,Bouchez, J.L., ErnestoGranite fabrics and regional scale strain partitioning in the Serido belt Boroborema Province NE Brasil.Tectonics, Vol.21,1,Feb.pp.3-1,3-14.BrazilStructure
DS201612-2285
2016
Archanjo, C.J.Cavalcante, G.C.C., Viegas, G., Archanjo, C.J.The influence of partial melting and melt migration on the rheology of the continental crust.Journal of Geodynamics, Vol. 101, pp. 186-199.MantleMelting

Abstract: The presence of melt during deformation produces a drastic change in the rheological behavior of the continental crust; rock strength is decreased even for melt fractions as low as ~7%. At pressure/temperature conditions typical of the middle to lower crust, melt-bearing systems may play a critical role in the process of strain localization and in the overall strength of the continental lithosphere. In this contribution we focus on the role and dynamics of melt flow in two different mid-crustal settings formed during the Brasiliano orogeny: (i) a large-scale anatectic layer in an orthogonal collision belt, represented by the Carlos Chagas anatexite in southeastern Brazil, and (ii) a strike-slip setting, in which the Espinho Branco anatexite in the Patos shear zone (northeast Brazil) serves as an analogue. Both settings, located in eastern Brazil, are part of the Neoproterozoic tectonics that resulted in widespread partial melting, shear zone development and the exhumation of middle to lower crustal layers. These layers consist of compositionally heterogeneous anatexites, with variable former melt fractions and leucosome structures. The leucosomes usually form thick interconnected networks of magma that reflect a high melt content (>30%) during deformation. From a comparison of previous work based on detailed petrostructural and AMS studies of the anatexites exposed in these areas, we discuss the rheological implications caused by the accumulation of a large volume of melt “trapped” in mid-crustal levels, and by the efficient melt extraction along steep shear zones. Our analyses suggest that rocks undergoing partial melting along shear settings exhibit layers with contrasting competence, implying successive periods of weakening and strengthening. In contrast, regions where a large amount of magma accumulates lack clear evidence of competence contrast between layers, indicating that they experienced only one major stage of dramatic strength drop. This comparative analysis also suggests that the middle part of both belts contained large volumes of migmatites, attesting that the orogenic root was partially molten and encompassed more than 30% of granitic melt at the time of deformation.
DS1999-0017
1999
Archbold, N.W.Archbold, N.W.Permian Gondwana correlations: the significance of the western Australian marine Permian.Journal of African Earth Sciences, Vol. 29, No. 1, July pp.63-75.AustraliaGondwana
DS1975-0452
1977
Archer, A.R.Archer, A.R., Schmidt, U.Mineralized Breccias of Early Proterozoic Age Bonnet Plume River District, Yukon Territory.Archer, Cathro And Associates, Preprint From The Canadian Institute of Mining, Metallurgy And Petroleum (cim) District, 16P. 3 FIGS.Canada, YukonRelated Rocks, Diatremes, Mountain
DS1975-0677
1978
Archer, A.R.Archer, A.R., Schmidt, U.Mineralized Breccias of Early Proterozoic Age, Bonnet Plume river District, Yukon Territory.The Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Vol. 71, No. 796, AUGUST PP. 53-58.Canada, YukonCopper, Porphyry
DS1998-0783
1998
ArchibaldKontak, D.J., Jensen, S.M., Dostal, ArchibaldPetrology of Late Cretaceous (CA 90 Ma) lamprophyric dykes from NorthGreenland.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A94. abstract.GreenlandDikes - lamprophyre, Petrography
DS2000-0232
2000
ArchibaldDigonnet, S., Goulet, N., Bourne, Stevenson, ArchibaldPetrology of the Abloviak aillikite dykes, New Quebec: evidence for Cambrian Diamondiferous alkaline provinceCanadian Journal of Earth Sciences, Vol. 37, No. 4, Apr. pp. 517-33.Quebec, Labrador, UngavaMineral chemistry - analyses, petrography, age, Geochronology, tectonics
DS2001-0622
2001
ArchibaldKontak, D.J., Jensen, S.M., Dostal, Archibald, KyserCretaceous mafic dike swarm, Peary Land, northern most Greenland: geochronology and petrology.Canadian Mineralogist, Vol. 39, No. 4, Aug. pp. 997-1020.GreenlandLamprophyres, Mantle plume
DS1996-1150
1996
Archibald, B.A.Queen, M., Heaman, L.M., Hanes, J.A., Archibald, B.A.40Ar/39Ar phlogopite and U- lead perovskite dating of lamprophyre dykes From the eastern Lake Superior regionCanadian Journal of Earth Sciences, Vol. 33, No. 6, June pp. 958-965.OntarioMidcontinent Rift volcanism., Geochronology
DS201705-0854
2017
Archibald, D.Merdith, A.S., Collins, A.S., Williams, S.E., Pisarevsky, S., Foden, J.F., Archibald, D., Blades, M.L., Alessio, B.L., Armistead, S., Plavsa, D., Clark, C., Muller, R.D.A full plate global reconstruction of the Neoproterozoic.Gondwana Research, in press available 155p.Gondwana, RodiniaGeodynamics

Abstract: Neoproterozoic tectonic geography was dominated by the formation of the supercontinent Rodinia, its break-up and the subsequent amalgamation of Gondwana. The Neoproterozoic was a tumultuous time of Earth history, with large climatic variations, the emergence of complex life and a series of continent-building orogenies of a scale not repeated until the Cenozoic. Here we synthesise available geological and palaeomagnetic data and build the first full-plate, topological model of the Neoproterozoic that maps the evolution of the tectonic plate configurations during this time. Topological models trace evolving plate boundaries and facilitate the evaluation of “plate tectonic rules” such as subduction zone migration through time when building plate models. There is a rich history of subduction zone proxies preserved in the Neoproterozoic geological record, providing good evidence for the existence of continent-margin and intra-oceanic subduction zones through time. These are preserved either as volcanic arc protoliths accreted in continent-continent, or continent-arc collisions, or as the detritus of these volcanic arcs preserved in successor basins. Despite this, we find that the model presented here still predicts less subduction (ca. 90%) than on the modern earth, suggesting that we have produced a conservative model and are likely underestimating the amount of subduction, either due to a simplification of tectonically complex areas, or because of the absence of preservation in the geological record (e.g. ocean-ocean convergence). Furthermore, the reconstruction of plate boundary geometries provides constraints for global-scale earth system parameters, such as the role of volcanism or ridge production on the planet's icehouse climatic excursion during the Cryogenian. Besides modelling plate boundaries, our model presents some notable departures from previous Rodinia models. We omit India and South China from Rodinia completely, due to long-lived subduction preserved on margins of India and conflicting palaeomagnetic data for the Cryogenian, such that these two cratons act as ‘lonely wanderers’ for much of the Neoproterozoic. We also introduce a Tonian-Cryogenian aged rotation of the Congo-São Francisco Craton relative to Rodinia to better fit palaeomagnetic data and account for thick passive margin sediments along its southern margin during the Tonian. The GPlates files of the model are released to the public and it is our expectation that this model can act as a foundation for future model refinements, the testing of alternative models, as well as providing constraints for both geodynamic and palaeoclimate models.
DS1986-0338
1986
Archibald, D.A.Hanes, J.A., Archibald, D.A., Lee, J.K.W.Reconnaissance 40 Ar-39 Ar geochronology of Kapuskasing,Matachewan and Hearst diabase dikes in the Kapuskasing structural zone and adjacent AbitibiGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 77. (abstract.)Ontario, QuebecTectonics, Geochronology, Argon, Dyke
DS1989-0032
1989
Archibald, D.A.Archibald, D.A., Hanes, J.A., Queen, M., Ross, D., Farrar, E.Summary of 40Ar/30Ar geochronology in the Kapuskasing upliftGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A103. (abstract.)OntarioTectonics, Kapuskasing Lithoprobe
DS1989-1247
1989
Archibald, D.A.Queen, M., Hanes, J.A., Archibald, D.A.40Ar 39Ar geochronology of dykes and their contact aureloes in the Kapuskasing uplift of the CanadianshieldGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A123. (abstract.)OntarioTectonics, Kapuskasing Zone
DS1994-0709
1994
Archibald, D.A.Hanes, J.A., Archibald, D.A., Queen, M., Farrar, E.Constraints from 40Ar/39Ar geochronology on the tectonothermal history Of the Kapuskasing uplift.Canadian Journal of Earth Sciences, Vol. 31, No. 7, July pp. 1146-1171.OntarioGeochronology, Tectonics -Kapuskasing uplift
DS1997-0066
1997
Archibald, D.A.Baksi, A.K., Archibald, D.A.Mesozoic igneous activity in the Maranhao, 40 Ar-39Ar evidence for seperate episodes of basaltic magmatismEarth and Planetary Science Letters, Vol. 151, No. 3-4, Oct.1, pp. 139-154Brazil, Maranhao ProvinceGeochronology, Argon, Magma - basalt
DS1998-0256
1998
Archibald, D.A.Clark, A.H., Archibald, D.A., Lee, A., Farrar, HodgsonLaser probe 40 Ar-39 Ar ages of early and late stage alteration assemblages Rosario porphyry copper moly..Economic Geology, Vol. 93, No. 3, May pp. 326-37ChileGeochronology, copper, molybdenuM., Deposit - Rosario, Argon
DS1998-0395
1998
Archibald, D.A.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
DS200512-0002
2005
Archibald, D.A.Adams, M.G., Lentz, D.R., Shaw, C.S., Williams, P.F., Archibald, D.A., Cousens, B.Eocene shoshonitic mafic dykes intruding the Monashee Complex, British Columbia: a petrogenetic relationship with the Kam loops Group volcanic sequence.Canadian Journal of Earth Sciences, Vol. 42, 1, pp. 11-24.Canada, British ColumbiaShoshonite
DS201709-2032
2017
Archibald, D.B.Meredith, A.S., Collins, A.S., Williams, S.E., Pisarevsky, S., Foden, J.D., Archibald, D.B., Blades, M.L., Alessio, B.L., Armistead, S., Plavsa, D., Clark, C., Muller, R.D.A full plate global reconstruction of the Neoproterozoic.Gondwana Research, Vol. 50, pp. 84-134.Globalneoproterozoic

Abstract: Neoproterozoic tectonic geography was dominated by the formation of the supercontinent Rodinia, its break-up and the subsequent amalgamation of Gondwana. The Neoproterozoic was a tumultuous time of Earth history, with large climatic variations, the emergence of complex life and a series of continent-building orogenies of a scale not repeated until the Cenozoic. Here we synthesise available geological and palaeomagnetic data and build the first full-plate, topological model of the Neoproterozoic that maps the evolution of the tectonic plate configurations during this time. Topological models trace evolving plate boundaries and facilitate the evaluation of “plate tectonic rules” such as subduction zone migration through time when building plate models. There is a rich history of subduction zone proxies preserved in the Neoproterozoic geological record, providing good evidence for the existence of continent-margin and intra-oceanic subduction zones through time. These are preserved either as volcanic arc protoliths accreted in continent-continent, or continent-arc collisions, or as the detritus of these volcanic arcs preserved in successor basins. Despite this, we find that the model presented here still predicts less subduction (ca. 90%) than on the modern earth, suggesting that we have produced a conservative model and are likely underestimating the amount of subduction, either due to a simplification of tectonically complex areas, or because of the absence of preservation in the geological record (e.g. ocean-ocean convergence). Furthermore, the reconstruction of plate boundary geometries provides constraints for global-scale earth system parameters, such as the role of volcanism or ridge production on the planet's icehouse climatic excursion during the Cryogenian. Besides modelling plate boundaries, our model presents some notable departures from previous Rodinia models. We omit India and South China from Rodinia completely, due to long-lived subduction preserved on margins of India and conflicting palaeomagnetic data for the Cryogenian, such that these two cratons act as ‘lonely wanderers’ for much of the Neoproterozoic. We also introduce a Tonian-Cryogenian aged rotation of the Congo-São Francisco Craton relative to Rodinia to better fit palaeomagnetic data and account for thick passive margin sediments along its southern margin during the Tonian. The GPlates files of the model are released to the public and it is our expectation that this model can act as a foundation for future model refinements, the testing of alternative models, as well as providing constraints for both geodynamic and palaeoclimate models.
DS1993-0090
1993
Archibald, J.F.Bawden, W.F., Archibald, J.F.Innovative mine design for the 21st century: proceedings of the International Congress on Mine Design held August 23-26, 1993, KingstonOntarioA.a. Balkema, 1046pGlobalMine Design, Conference proceedings
DS1988-0450
1988
Architzel, R.J.McCartan, L., Architzel, R.J.Heat flow map of the Eastern United StatesUnited States Geological Survey (USGS) Map, (Colour), No. MF 2057 2 - 1:2, 500, 000; 2, 1:7, 500, 000 $4.80Appalachia, MidcontinentGeophysics, Heat flow
DS201112-0028
2011
Arctic Gold ABArctic Gold ABDiamonds in Sweden? ( formerly company name Alcaston Diamond) brief overview of three diamond claims ( map)Arctic Gold AB., 1p. Europe, SwedenNews item - Alcaston
DS1992-0476
1992
Arculus, R.Fountain, D.M., Arculus, R., Kay, R.M.Continental Lower Crust #3Elsevier, 700p. $ approx. $ 120.00MantleMantle -lower continental crust, Xenoliths
DS1992-0477
1992
Arculus, R.Fountain, D.M., Arculus, R., Kay, R.M.Continental lower crust #1Elsevier, approx. $ 120.00GlobalBook -ad, Continental lower crust
DS1992-0478
1992
Arculus, R.Fountain, D.M., Arculus, R., Kay, R.W.Continental lower crust #2Elsevier, 485pGlobalCrust, lithosphere, magma, fluids, granulite terranes, Geophysics, seismics, MOHO, xenoliths
DS1998-0828
1998
Arculus, R.Lapierre, H., Arculus, R., Ballevre, M., Bosch, D.Accreted eclogites with oceanic plateau basalt affinities in EcuadorMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 852-3.EcuadorRaspas Formation, MetmorphisM., Eclogites
DS200412-1884
2004
Arculus, R.Spandler,C., Hermann, J., Arculus, R., Mavrogenes, J.Geochemical heterogeneity and element mobility in deeply subducted oceanic crust; insights from high-pressure mafic rocks from NChemical Geology, Vol. 206, 1-2, May 28, pp. 21-42.New CaledoniaSubduction, geochemistry, eclogite
DS200612-0033
2006
Arculus, R.Arculus, R., Bebout, G.Fluid loss during early subduction.Goldschmidt Conference 16th. Annual, S6-01 theme abstract 1/8p. goldschmidt2006.orgMantleMetamorphism
DS200612-0370
2006
Arculus, R.Elburg, M.A., Kamenetsky, V.S., Arculus, R., Thomas, R.Low calcium olivine crystals in subduction related magmas: messengers from the mantle or the magma chamber?Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 157, abstract only.MantleSubduction
DS200612-0657
2006
Arculus, R.Kamenetsky, V.S., Elburg, M., Arculus, R., Thomas, R.Magmatic origin of low Ca olivine in subduction related magmas: co-existence of contrasting magmas.Chemical Geology, In press availableAsia, Indonesia, Solomon IslandsMagmatism, picrites, subduction
DS200612-0658
2006
Arculus, R.Kamenetsky, V.S., Elburg, M., Arculus, R., Thomas, R.Magmatic origin of low Ca olivine in subduction related magmas: co-existence of contrasting magmas.Chemical Geology, Vol. 233, 3-4, Oct. 15, pp. 346-357.MantleSubduction
DS200612-0659
2006
Arculus, R.Kamenetsky, V.S., Elburg, M., Arculus, R., Thomas, R.Magmatic origin of low Ca olivine in subduction related magmas: co-existence of contrasting magmas.Chemical Geology, In press availableIndonesia, Solomon Islands, KamchatkaSubduction, magmatism, picrites
DS1970-0352
1971
Arculus, R.J.Mcdowell, F.W., Roden, M.F., Arculus, R.J., Smith, D.Potassic Volcanism and Associated Inclusion on the Coloradoplateau.Geological Society of America (GSA), Vol. 10, P. 116, (abstract.).Colorado PlateauKimberlite, Rocky Mountains
DS1975-0926
1979
Arculus, R.J.Arculus, R.J., Ferguson, J., Knutson, J., Chappell, B.W.Petrochemistry of Crustal and Upper Mantle Nodules from Kimberlite Pipes of Southeast Australia.B.m.r. Rec. Min. Res. Geol. Geophys., 1979/2, P. 2, (abstract.).Australia, New South Wales, VictoriaKimberlite, Xenoliths
DS1975-0927
1979
Arculus, R.J.Arculus, R.J., Smith, D.Eclogite, Pyroxenite and Amphibolite Inclusions in the Sullivan Buttes Latite, Chino Valley, Yavapai County, Arizona.International Kimberlite Conference SECOND Proceedings, Vol. 2, PP. 309-317.GlobalKimberlite, Colorado Plateau, Rocky Mountains
DS1975-1016
1979
Arculus, R.J.Ferguson, J., Arculus, R.J., Joyce, J.Kimberlite and Kimberlitic Intrusives of Southeastern Australia: a Review.B.m.r. Journal of Aust. Geol. Geophys., Vol. 4, PP. 227-241.Australia, New South Wales, VictoriaKimberlite, Nepheline Basanites
DS1982-0069
1982
Arculus, R.J.Arculus, R.J., Dawson, J.B., Mitchell, R.H., Gust, D.A.The Intrinsic Oxygen Fugacities of Megacryst Ilmenites From southern African Kimberlites, Type a and B Spinel Peridotites from San Carlos, Arizona.Proceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 228, (abstract.).ArizonaKimberlite, Colorado Plateau Rocky Mountains
DS1982-0422
1982
Arculus, R.J.Mcculloch, M.T., Arculus, R.J., Chappell, B.W., Ferguson, J.Isotopic and Geochemical Studies of Nodules in Kimberlite Have Implications for the Lower Continental Crust.Nature., Vol. 300, No. 5888, Nov. 11, PP. 166-169.AustraliaCalcutteroo, Rare Earth Elements (ree), Xenolith, Geochemistry, Kimberlite
DS1983-0105
1983
Arculus, R.J.Arculus, R.J., Gust, A.D., Holmes, R.D., et al.Oxidation States of the Mantle and Controls on Evolved VolatilesLpi Tech. Report, No. 83-01, pp. 16-17GlobalKimberlite, Geochemistry
DS1984-0115
1984
Arculus, R.J.Arculus, R.J., Dawson, J.B., Mitchell, R.H., Gust, D.A., Holmes, R.D.Oxidation States of the Upper Mantle Recorded by Megacryst Ilmenite in Kimberlite and Type a and B Spinel Lherzolites.Contributions to Mineralogy and Petrology, Vol. 85, No. 1, PP. 85-94.South Africa, Solomon Islands, ArizonaMineral Chemistry, Genesis, Franklk Smith, Excelsior, Sekameng
DS1985-0022
1985
Arculus, R.J.Arculus, R.J.Oxidation Status of the Mantle- Past and Present ( Review)Annual Review Earth Science., Vol. 13, PP. 75-95.GlobalBlank
DS1985-0332
1985
Arculus, R.J.Keating, S.J., Arculus, R.J.Thermobarometry of Cumulate Xenoliths: Implications for Basalt Ponding Under the Colorado Plateau, Arizona.Geological Society of America (GSA), Vol. 17, No. 7, P. 624. (abstract.).United States, Colorado Plateau, ArizonaPetrology
DS1986-0325
1986
Arculus, R.J.Gust, D.A., Arculus, R.J.Petrogenesis of alkalic and calcalkalic volcanic rocks of Mormon volcanic field, ArizonaContributions to Mineralogy and Petrology, Vol. 94, No. 4, pp. 416-426ArizonaPetrogenesis
DS1987-0014
1987
Arculus, R.J.Arculus, R.J.The significance of source versus process in the tectonic controls of magma genesisJournal of Volcanology, Vol. 32, No. 1-3, June pp. 1-12GlobalMantle genesis
DS1989-0762
1989
Arculus, R.J.Kersting, A.B., Peacor, D.R., Arculus, R.J.STEM study of preserved diffusion gradients in lower crustal Upper Mantle spinel megacrysts, KilbourneHole, New MexicoEos, Vol. 70, No. 43, October 24, p. 1393. AbstractNew MexicoMegacrysts, STEM.
DS1993-0243
1993
Arculus, R.J.Chen, W., Arculus, R.J.The composition of lower crust under the San Francisco volcanic field, northern Arizona: xenolith evidence.The Xenolith window into the lower crust, abstract volume and workshop, p. 2.ArizonaXenoliths
DS1994-0061
1994
Arculus, R.J.Arculus, R.J.Aspects of magma genesis in arcsLithos, Vol. 33, pp. 189-208MantleMagma genesis, Subduction -arcs
DS1994-1631
1994
Arculus, R.J.Smith, D., Arculus, R.J., Manchester, J.E., Tyner, G.Garnet pyroxenite amphibole xenoliths from Chino Valley Arizona, And implications for continental lithosphere below the MohoJournal of Geophysical Research, Vol. 99, No. B 1, January 10, pp. 683-696ArizonaXenoliths
DS1994-1632
1994
Arculus, R.J.Smith, D., Arculus, R.J., Manchester, J.E., Tyner, G.N.Garnet pyroxene amphibole xenoliths from Chino Valley, Arizona, And implications for continental lithosphere below the mantle.Journal of Geophysical Research, Vol. 99, No. B 1, January 10, pp. 683-696.ArizonaXenoliths
DS1995-0304
1995
Arculus, R.J.Chen, W., Arculus, R.J.Geochemical and isotopic characteristics of lower crustal xenoliths, San Francisco volcanic field.Lithos, Vol. 36, No. 3/4, Dec. 1, pp. 203-226.ArizonaGeochronology, Xenoliths
DS1999-0018
1999
Arculus, R.J.Arculus, R.J., Lapierre, H., Jaillard. E.Geochemical window into subduction and accretion processes: Raspas metamorphic complex, Ecuador.Geology, Vol. 27, No. 6, June, pp. 547-50.EcuadorLithosphere, subduction, Geochemistry - Raspas
DS2003-1348
2003
Arculus, R.J.Sun, W., Bennett, V.C., Eggins, S.M., Kamenetsky, V.S., Arculus, R.J.Enhanced mantle to crust rhenium transfer in under gassed arc magmasNature, No. 6929, March 20, pp. 294-6.MantleGeochemistry
DS2003-1546
2003
Arculus, R.J.Zhang, L., Ellis, D.J., Arculus, R.J., Jiang, W., Wei, C.Forbidden zone subduction of sediments to 150 km depth - the reaction of dolomite toJournal of Metamorphic Geology, Vol. 21, 6, pp. 523-30.ChinaSubduction, UHP
DS200412-2205
2003
Arculus, R.J.Zhang, L., Ellis, D.J., Arculus, R.J., Jiang, W., Wei, C.Forbidden zone subduction of sediments to 150 km depth - the reaction of dolomite to magnesite + aragonite in the UHPM metapelitJournal of Metamorphic Geology, Vol. 21, 6, pp. 523-30.ChinaSubduction, UHP
DS200512-0805
2005
Arculus, R.J.Okamura, S., Arculus, R.J., Martynov, Y.A.Cenozoic magmatism of the north eastern Eurasian margin: the role of lithosphere versus asthenosphere.Journal of Petrology, Vol. 46, no. 2, pp. 221-253.Europe, Baltic ShieldMagmatism - not specific to diamonds
DS200612-0034
2006
Arculus, R.J.Arculus, R.J.Role of the overriding plate in arc magma evolution.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 21, abstract only.MantleMagmatism
DS200612-0310
2006
Arculus, R.J.Davidson, J.P., Arculus, R.J.The significance of Phanerozoic arc magmatism in generating continental crust.Evolution and differentiation of Continental Crust, ed. Brown, M., Rushmer, T., Cambridge Univ. Press, Chapter 2, pp. 135-172.MantleGeochemistry
DS200612-0311
2006
Arculus, R.J.Davidson, J.P., Arculus, R.J.The significance of Phanerozoic arc magmatism in generating continental crust.Brown, M., Rushmer, T., Evolution and differentiation of the continental crust, Cambridge Publ., Chapter 5,MantleMagmatism
DS200812-1142
2008
Arculus, R.J.Sun, W., Kamentesky, V.S., Eggins, S.M., Chen, M., Arculus, R.J.Constancy of NB/U in the mantle revisited.Geochimica et Cosmochimica Acta, Vol. 72, 14, pp. 3542-3549.MantleMorb chemistry
DS201312-0025
2013
Arculus, R.J.Arculus, R.J.Insights into mantle processes from water and trace elements in olivine.Goldschmidt 2013, AbstractMantleSubduction
DS201312-0026
2013
Arculus, R.J.Arculus, R.J.Subduction zones as probes of mantle composition.Goldschmidt 2013, AbstractMantleSubduction
DS201812-2779
2018
Arculus, R.J.Benard, A., Klimm, K., Woodland, A.B., Arculus, R.J., Wilke, M., Botcharnikov, R.E., Shimizu, N., Nebel, O., Rivard, C., Ionov, D.A.Oxidising agents in sub-arc mantle melts link slab devolatillisation and arc magmas.Nature Communications, Vol. 9, 1, doi: 10.1038/s41467-018-05804-2 11p.Mantlemelting

Abstract: Subduction zone magmas are more oxidised on eruption than those at mid-ocean ridges. This is attributed either to oxidising components, derived from subducted lithosphere (slab) and added to the mantle wedge, or to oxidation processes occurring during magma ascent via differentiation. Here we provide direct evidence for contributions of oxidising slab agents to melts trapped in the sub-arc mantle. Measurements of sulfur (S) valence state in sub-arc mantle peridotites identify sulfate, both as crystalline anhydrite (CaSO4) and dissolved SO42- in spinel-hosted glass (formerly melt) inclusions. Copper-rich sulfide precipitates in the inclusions and increased Fe3+/?Fe in spinel record a S6+Fe2+ redox coupling during melt percolation through the sub-arc mantle. Sulfate-rich glass inclusions exhibit high U/Th, Pb/Ce, Sr/Nd and d34S (+?7 to +?11‰), indicating the involvement of dehydration products of serpentinised slab rocks in their parental melt sources. These observations provide a link between liberated slab components and oxidised arc magmas.
DS1995-0823
1995
Arden, H.J.Hough, R.M., Gilmour, I., Pillinger, C.T., Arden, H.J.Diamond and silicon carbide in impact melt rock from the Ries impactcrater.Nature, Vol. 378, No. 6552, Nov. 2, pp. 41-44.GlobalDiamond, SIC., Deposit -Ries crater
DS1992-0570
1992
Arden, J.W.Gilmour, I., Russell, S.S., Arden, J.W., Lee, M.R., Franchi, I.A.Terrestrial carbon and nitrogen isotopic ratios from Cretaceous-Tertiary boundary nanodiamondsScience, Vol. 258, December 4, pp. 1624-1626GlobalGeochronology, Nanodiamonds
DS1992-1315
1992
Arden, J.W.Russell, S.S., Pillenger, C.T., Arden, J.W., Lee, M.R.A new type of meteoritic diamond in the enstatite chondrite AbeeScience, Vol. 256, No. 5054, April 10, pp. 206-209GlobalMeteorites, Diamond
DS1999-0019
1999
Arden, K.M.Arden, K.M., DePaoli, Johnson, Hemstock, AbercrombieMetallic and industrial mineral assessment report on the Athabasca permitsin northeastern Alberta.Alberta Geological Survey, MIN 19990004AlbertaExploration - assessment, Birch Mountain Resources Ltd.
DS201212-0020
2012
Ardia, P.Ardia, P., Hirschmann, M.M., Withers, A.C., Tenner, T.J.H2O storage capacity of olivine at 5-8 Gpa and consequences for dehydration partial melting of the upper mantle.Earth and Planetary Science Letters, Vol. 345-348, pp. 104-116.MantleMelting
DS201212-0021
2012
Ardit, M.Ardit, M., Dondi, M., Merlini, M., Cruciani, G.Melilite-type and melilite related compounds: structural variations along the join Sr2a, Bax, MgS2iO7 and high pressure behaviour of the two end members.Physics and Chemistry of Minerals, Vol. 39, 3, pp.199-211.TechnologyMelilite
DS1989-0033
1989
Ardoh, A.Ardoh, A., Pilkington, M.Radon emanation studies of the Ile Bizard fault, MontrealGeoexploration, Vol. 25, pp. 341-354QuebecGeophysics, Radon
DS201412-0013
2014
Ardon, T.Ardon, T., Magana, S.Spatial correlation of infrared and PL optical centers in hydrogen rich diamonds.Geological Society of America Conference Vancouver Oct. 19-22, 1p. AbstractAfrica, ZimbabweDiamond absorption
DS201510-1766
2015
Ardon, T.Eaton-Magana, S., Ardon, T.Effect of LPHT treatment on natural Type 1A diamonds.GSA Annual Meeting, Paper 300-10, 1p. Abstract only BoothTechnologyLPHT
DS201608-1389
2016
Ardon, T.Ardon, T., Eaton-Magana, S.High temperature annealing of hydrogen rich diamonds.GSA Annual Meeting, Abstract, Poster 1p.TechnologyType IIb diamonds

Abstract: This study gives an analysis of the effect of high temperature annealing on the infrared and photoluminescence (PL) features as well as the inclusions of two hydrogen-rich diamond plates from Zimbabwe that were cut from the same rough. The samples showed strong inclusion-related zoning known as hydrogen clouds which consist of micron-sized particles of as yet undetermined structure. This allowed hydrogen-rich and hydrogen-poor areas to be compared throughout the annealing study. The diamond plates were annealed to temperatures of 300oC, 600oC, 800oC, 1000oC, 1400oC, and 1700oC. The infrared and PL, and Raman maps were collected after every temperature step to study the effects of heat on the defects, and photomicrographs were collected to study the inclusions. Several photoluminescence features were seen to decrease in size including the 637 nm peak, which is the negatively charged nitrogen-vacancy center [NV-] and the 503.2 nm peak, known as the H3 and consists of two nitrogen atoms and vacancy in the neutral charge state and normally has a high thermal stability. The H2 defect at 986.2 nm, which is the negative form of the H3, was shown to increase after annealing. The hydrogen clouds underwent dramatic changes in apparent color and particle size, going from a light translucent gray appearance to an opaque black. The particle size grew from less than one micron to an average of fourteen microns, and the hexagonal outline of the particles became noticeable. Spatial raman spectroscopy was used to show that the color change and size change were due to graphitization of the included particles.
DS201608-1401
2016
Ardon, T.Eaton-Magana, S., Ardon, T.Temperature effects on luminescence centers in natural type.Diamond and Related Materials, Vol. 69, pp. 86-95India, Africa, South AfricaType IIb diamonds

Abstract: Blue diamonds are among the rarest and most valuable of naturally occurring gemstones. In this study, 12 rough naturally-sourced type IIb diamonds were subjected to HPHT annealing, three different irradiation energies, and then all were stepwise annealed from 200 °C to 1100 °C and the optical defects were documented by changes in phosphorescence and photoluminescence spectroscopy. Several optical features that are removed from natural type IIb diamonds by HPHT processing, such as 3H, 648.2 nm peak, 776.4 nm peak, and 660 nm band (red) phosphorescence, can be reintroduced into these diamonds with subsequent electron irradiation and annealing at low-to-moderate temperatures. The thermal stability of these centers along with their spatial distribution provided additional insights into their configuration and distinguished them from nitrogen-bearing diamonds.
DS201610-1841
2016
Ardon, T.Ardon, T., Eaton-Magana, S.High temperature annealing of hydrogen-rich diamonds.GSA Annual Meeting, 1/2p. AbstractAfrica, ZimbabwePhotoluminescence

Abstract: This study gives an analysis of the effect of high temperature annealing on the infrared and photoluminescence (PL) features as well as the inclusions of two hydrogen-rich diamond plates from Zimbabwe that were cut from the same rough. The samples showed strong inclusion-related zoning known as hydrogen clouds which consist of micron-sized particles of as yet undetermined structure. This allowed hydrogen-rich and hydrogen-poor areas to be compared throughout the annealing study. The diamond plates were annealed to temperatures of 300oC, 600oC, 800oC, 1000oC, 1400oC, and 1700oC. The infrared and PL, and Raman maps were collected after every temperature step to study the effects of heat on the defects, and photomicrographs were collected to study the inclusions. Several photoluminescence features were seen to decrease in size including the 637 nm peak, which is the negatively charged nitrogen-vacancy center [NV-] and the 503.2 nm peak, known as the H3 and consists of two nitrogen atoms and vacancy in the neutral charge state and normally has a high thermal stability. The H2 defect at 986.2 nm, which is the negative form of the H3, was shown to increase after annealing. The hydrogen clouds underwent dramatic changes in apparent color and particle size, going from a light translucent gray appearance to an opaque black. The particle size grew from less than one micron to an average of fourteen microns, and the hexagonal outline of the particles became noticeable. Spatial raman spectroscopy was used to show that the color change and size change were due to graphitization of the included particles.
DS201702-0212
2017
Ardon, T.Eaton-Magana, S., Ardon, T., Zaitsev, A.M.Inclusion and point defect characteristics of Marange graphite bearing diamonds after high temperature annealing.Diamond and Related Materials, Vol. 71, pp. 20-29,Africa, ZimbabweDeposit - Marange

Abstract: This study gives an analysis of the effect of low-pressure, high-temperature annealing on the infrared, Raman, and photoluminescence (PL) features, as well as the inclusion characteristics, of cubo-octahedral diamond plates from the Marange deposits in Zimbabwe. The samples showed strong inclusion-related zoning which consists of micron-sized particles identified as graphite and these grew noticeably larger with annealing at temperatures of 300 °C to 1700 °C. Within the natural diamonds, the graphite inclusions (detected by Raman spectroscopy) had a grain size of approximately 1 µm, which increased to 3 µm after 1200 °C and 14 µm after 1700 °C annealing and their hexagonal morphology was discernible. From the geometry of these grains, we determined that they were oriented within the {111} family of planes. The infrared absorption and PL spatial maps were collected after every temperature step to study the effects of annealing on the defects, and photomicrographs and Raman spectra were collected to study the graphite inclusions. The graphitic inclusions grew much larger as the stressed diamond surrounding them converted to graphite. Many nitrogen-related optical centers, including NV- and H3 are no longer detected after high temperature annealing within the cuboid regions as these may have been transformed to hydrogen-bearing complexes such as NVH and N2VH. The presence of CH4 is detected in the unannealed Marange diamonds, but was no longer observed in Raman spectra after 1200 °C annealing. This CH4 disappearance along with changes in inclusion morphology could provide a method to detect heat treatment if these mixed-habit samples are sourced to create treated black gem diamond.
DS201708-1569
2017
Ardon, T.Eaton-Magana, S., Ardon, T., Zaitsev, A.M.LPHT annealing of brown to yellow type 1a diamonds.Diamond and Related Materials, Vol. 77, pp. 159-170.Technologydiamond morphology

Abstract: Low-pressure, high-temperature (LPHT) annealing of yellow-to-brown type Ia natural diamonds was performed to monitor its effects on optical centers within diamond, changes in the observed color, and to assess the process's viability as a commercial gem treatment. With LPHT annealing only, the mostly brown diamonds showed a shift towards yellow coloration; Vis-NIR absorption spectra showed this change was due to a modest increase in H3 intensity. Even at long annealing times (24 h at 1800 °C) or annealing at high temperatures (2000 °C for five minutes), the diamonds did not significantly lose brown coloration. LPHT annealing showed itself as an ineffective means to break apart the vacancy clusters causing the brown color or causing nitrogen disaggregation, which resulted in only a small H3 generation. With LPHT annealing, “amber centers”—a group of several independent bands in the IR between 4200 and 4000 cm- 1 that disappear with HPHT annealing—were seen to anneal out gradually at various temperatures from 1700 to 2000 °C. In contrast, high-pressure, high-temperature (HPHT) annealing effectively removes brown color at similar time/temperature conditions. Without the high stabilizing pressure provided by HPHT annealing techniques, the LPHT annealing showed pronounced damage on inclusions and dramatic surface etching. In subsequent experiments, LPHT annealing was used as a follow-up to laboratory irradiation. The irradiation-related vacancies created greater concentrations of H3 and the vacancy-assisted disaggregation of nitrogen created donors which led to a high concentration of H2 centers. This combination of defects resulted in a pronounced and favorable shift towards saleable yellow colors due to an increase in H3 and a dramatic increase in the H2 center, which led to the suppression of the remaining brownish component. The annealing characteristics for many centers detected by Vis-NIR absorption spectroscopy, FTIR absorption spectroscopy, and photoluminescence spectroscopy were chronicled throughout the study and compared with other LPHT annealing studies and HPHT annealing experiments.
DS201806-1209
2018
Ardon, T.Ardon, T., Ahline, N.Fancy deep brown-orange CVD synthetic diamond. 0.56 ctGems & Gemology, Vol. 54, 1, p. 64Technologysynthetics
DS201903-0505
2018
Ardon, T.Eaton-Magana, S., Ardon, T., Smit, K.V., Breeding, C.M., Shigley, J.E.Natural color pink, purple, red and brown diamonds: band of many colors.Gems & Gemology, Vol. 54, 4, pp. 352-377.Global, Australiadiamond colour

Abstract: Diamond is one of Earth’s most extraordinary materials. It represents the pinnacle for several material and physical properties. As a gem, however, it is the near-perfect examples—diamonds attaining the D-Flawless distinction—and those with imperfections resulting in a vibrant or surprising color that create the most enduring impressions. Fancy-color natural diamonds are among the most highly valued gemstones due to their attractiveness and great rarity. The 18.96 ct Winston Pink Legacy, with a color grade of Fancy Vivid pink, recently made history by selling at over $50 million, its $2.6 million per carat price an all-time high for a pink diamond (Christie’s, 2018).
DS202001-0009
2019
Ardon, T.Eaton-Magana, S., Ardon, T., Breeding, C.M., Shigley, J.E.Natural color fancy white and fancy black diamonds: where color and clarity converge.Gems & Gemology, Vol. 55, 3, pp. 320-336.Globalreview

Abstract: Natural Fancy white and Fancy black diamonds are not routinely submitted to GIA for grading (fewer than 2,000 since 2008). These fancy-color diamonds are distinctive since the causes of color generally are not atomic-scale defects, but nanometer- to micrometer-sized inclusions that reduce the diamond’s transparency by scattering or absorbing light (some exceptions exist among Fancy black diamonds). To clarify, Fancy white diamonds are those rare stones colored by inclusions that give a “whitish” appearance, and are distinct from “colorless” diamonds on the D-to-Z scale. These two colors, often thought of as opposites in the color world, are grouped here as outliers within the colored diamond world. Both can be colored by inclusions so numerous the stone would fall below the I3 grade on the clarity scale, demonstrating that inclusions, often perceived as a negative quality factor, can create a distinctive appearance. Among the Fancy white diamonds examined for this study, the vast majority (82%) were type IaB, making them a rare subset of a rare diamond type. Based on prior geological research, these are surmised to be mostly sublithospheric in origin (i.e., forming more than 250 km below the earth’s surface). The Fancy white diamonds generally have a different chemistry from D-to-Z type IaB diamonds, with greater quantities of several hydrogen- and nickel-related defects. Among Fancy black diamonds, the major causes of color are either micrometer-sized dark crystal inclusions, nanometer-sized inclusions clustered into clouds, or a combination of the two. For these two colors of diamond, we summarize their gemological properties along with the absorption and luminescence spectra of a representative subset of diamonds from each color, examining how they deviate from the standard grading methodology. Because of their rarity, there has been very little systematic study of either of these color categories, and never a sample set of this quantity, which includes data for ~500 Fancy white and ~1,200 Fancy black diamonds.
DS202006-0918
2020
Ardon, T.Eaton-Magana. S., McElhenny, G., Breeding, C.M., Ardon, T.Comparison of gemological and spectroscopic features in type IIa and Ia natural pink diamonds.Diamonds & Related Materials, Vol. 105, 13p. PdfMantlenitrogen

Abstract: The majority of natural pink diamonds have a color origin due to absorption from a broad 550?nm band that has been associated with plastic deformation. One consistent feature in the photoluminescence spectra of these pink diamonds is a wide emission band extending from ~600 to 750?nm, with a series of smaller oscillations overlaid on the larger emission band. This "pink emission band" is seen in diamonds colored by the 550?nm absorption band; the absorption band often, but not always, shows similar oscillations at ~600?nm (called the 609?nm system by previous researchers). This emission band served as a proxy for the 550?nm absorption band as we performed spatial mapping to chronicle the differences between the uniform coloration in type IIa pink diamonds and the pronounced banding in type Ia pink diamonds. We also used Raman spectroscopy to identify the internal crystal inclusions present in type IIa pink diamonds and determined that the majority have a sub-lithospheric origin.
DS1920-0221
1925
Ardouin, W.Ardouin, W.Digging for Diamonds. #3Chambers's Journal, Vol. 51, No. 7, PP. 95-96.South AfricaCurrent Activities
DS2000-0866
2000
Areback, H.Schersten, A., Areback, H., Armstrong, R.Dating mafic - ultramafic intrusions by ion microprobing contact melt zircon: examples from southwest...Contrib. Min. Pet., Vol. 139, No. 1, pp. 115-SwedenGeochronology
DS201903-0539
2019
Arefiev, A.V.Podborodnikov, I.V., Shatskiy, A., Arefiev, A.V., Litasov, K.D.Phase relations in the system Na2COs-CaCO3 at 3 Gpa with implications for carbonatite genesis and evolution.Lithos, in press available 43p.Mantlecarbonatite

Abstract: The phase relations in the system Na2CO3-CaCO3-MgCO3 have been studied at 3?GPa and 700-1285?°C using a Kawai-type multianvil press. At 700?°C, the system has five intermediate compounds: dolomite, Mg-bearing Na2Ca4(CO3)5 burbankite, Na2Ca3(CO3)4, Na4Ca(CO3)3, and eitelite. As temperature increases to 800?°C, the system is complicated by an appearance of Ca-dolomite and Mg-bearing shortite, while Na2Ca4(CO3)5 disappears. At 850?°C, Na4Ca(CO3)3 decomposes to produce Na carbonate and nyerereite. The latter melts incongruently at 875?±?25?°C to form Na2Ca3(CO3)4. Incongruent melting of eitelite to magnesite and liquid, occurs at 925?±?25 °C. Mg-bearing shortite melts incongruently at 950?±?50?°C, producing Na2Ca3(CO3)4 and liquid. Na2Ca3(CO3)4 disappears at 1000?°C via incongruent melting to calcite and liquid. The liquidus projection of the studied ternary system has seven primary solidification phase regions for magnesite, dolomite-calcite solid solutions, Na2Ca3(CO3)4, Mg-bearing shortite, nyerereite, eitelite, and Na carbonate. The primary solidification regions are separated by five peritectic and three cotectic monovariant lines. The system has six ternary peritectic points and one minimum on the liquidus at 850?°C and 52Na2CO3·48(Ca0.62Mg0.38)CO3. The minimum point resembles a eutectic controlled by a four-phase reaction, by which, on cooling, a liquid transforms into three solid phases: shortite, Na carbonate, and eitelite. Since the system has a single eutectic at 3?GPa, there is no thermal barrier preventing continuous liquid fractionation from Na-poor toward Na-rich dolomitic compositions more alkaline than eitelite and nyerereite. Considering the present results and previous data, a range of Na-Ca-Mg double carbonates changes in the following sequence upon pressure and temperature increase: Na2Ca2(CO3)3 (Amm2) shortite, Na2Ca(CO3)2 (P21ca) nyerereite, Na2Mg(CO3)2 () eitelite (0.1?GPa)???Na2(Ca0.97-0.98Mg0.02-0.03)4(CO3)5 (P63mc), Na2(Ca=0.91Mg=0.09)3(CO3)4 (P1n1), Na2(Ca?=?0.81?Mg0=0.19)(CO3)2 () nyerereite, Na2(Ca0.77-0.93Mg0.07-0.23)2(CO3)3 (Amm2) shortite, Na4(Ca0.90-0.98Mg0.02-0.10)(CO3)3 (Ia3d), Na2(Mg=0.9Ca0=0.1)(CO3)2 (P21ca) eitelite (3?GPa)???Na2(Ca=0.87Mg0=0.13)4(CO3)5 (P63mc), Na2(Ca=0.89Mg=0.11)3(CO3)4 (P1n1), Na4(Ca?=?0.7?Mg0=0.3)(CO3)3 (Ia3d), Na2(Mg=0.92Ca0=0.08)(CO3)2 (P21ca) eitelite (6?GPa). Using the present results at 3?GPa and previous data at 6?GPa in the Na2CO3-CaCO3-MgCO3 system, we constrained isopleths of the Na2CO3 content in melt coexisting with Ca-Mg carbonates. We found that the cratonic geotherms cross the isopleths so that the carbonatite melt percolating upward via the continental mantle lithosphere should become progressively enriched in Na, evolving from alkali-poor dolomitic composition at depths exceeding 200?km toward sodic dolomitic with the ~52?mol% Na2CO3 at 80-120?km depths.
DS201905-1067
2019
Arefiev, A.V.Podborodnikov, I.V., Shatskiy, A., Arefiev, A.V., Litasov, K.D.Phase relations in the system Na2CO3-CaCO3-MgCO3 at 3 GPa with implications for carbonatite genesis and evolution.Lithos, Vol. 330-331, pp. 74-89.Mantlecarbonatite

Abstract: The phase relations in the system Na2CO3-CaCO3-MgCO3 have been studied at 3?GPa and 700-1285?°C using a Kawai-type multianvil press. At 700?°C, the system has five intermediate compounds: dolomite, Mg-bearing Na2Ca4(CO3)5 burbankite, Na2Ca3(CO3)4, Na4Ca(CO3)3, and eitelite. As temperature increases to 800?°C, the system is complicated by an appearance of Ca-dolomite and Mg-bearing shortite, while Na2Ca4(CO3)5 disappears. At 850?°C, Na4Ca(CO3)3 decomposes to produce Na carbonate and nyerereite. The latter melts incongruently at 875?±?25?°C to form Na2Ca3(CO3)4. Incongruent melting of eitelite to magnesite and liquid, occurs at 925?±?25 °C. Mg-bearing shortite melts incongruently at 950?±?50?°C, producing Na2Ca3(CO3)4 and liquid. Na2Ca3(CO3)4 disappears at 1000?°C via incongruent melting to calcite and liquid. The liquidus projection of the studied ternary system has seven primary solidification phase regions for magnesite, dolomite-calcite solid solutions, Na2Ca3(CO3)4, Mg-bearing shortite, nyerereite, eitelite, and Na carbonate. The primary solidification regions are separated by five peritectic and three cotectic monovariant lines. The system has six ternary peritectic points and one minimum on the liquidus at 850?°C and 52Na2CO3·48(Ca0.62Mg0.38)CO3. The minimum point resembles a eutectic controlled by a four-phase reaction, by which, on cooling, a liquid transforms into three solid phases: shortite, Na carbonate, and eitelite. Since the system has a single eutectic at 3?GPa, there is no thermal barrier preventing continuous liquid fractionation from Na-poor toward Na-rich dolomitic compositions more alkaline than eitelite and nyerereite. Considering the present results and previous data, a range of Na-Ca-Mg double carbonates changes in the following sequence upon pressure and temperature increase: Na2Ca2(CO3)3 (Amm2) shortite, Na2Ca(CO3)2 (P21ca) nyerereite, Na2Mg(CO3)2 () eitelite (0.1?GPa)???Na2(Ca0.97-0.98Mg0.02-0.03)4(CO3)5 (P63mc), Na2(Ca=0.91Mg=0.09)3(CO3)4 (P1n1), Na2(Ca?=?0.81?Mg0=0.19)(CO3)2 () nyerereite, Na2(Ca0.77-0.93Mg0.07-0.23)2(CO3)3 (Amm2) shortite, Na4(Ca0.90-0.98Mg0.02-0.10)(CO3)3 (Ia3d), Na2(Mg=0.9Ca0=0.1)(CO3)2 (P21ca) eitelite (3?GPa)???Na2(Ca=0.87Mg0=0.13)4(CO3)5 (P63mc), Na2(Ca=0.89Mg=0.11)3(CO3)4 (P1n1), Na4(Ca?=?0.7?Mg0=0.3)(CO3)3 (Ia3d), Na2(Mg=0.92Ca0=0.08)(CO3)2 (P21ca) eitelite (6?GPa). Using the present results at 3?GPa and previous data at 6?GPa in the Na2CO3-CaCO3-MgCO3 system, we constrained isopleths of the Na2CO3 content in melt coexisting with Ca-Mg carbonates. We found that the cratonic geotherms cross the isopleths so that the carbonatite melt percolating upward via the continental mantle lithosphere should become progressively enriched in Na, evolving from alkali-poor dolomitic composition at depths exceeding 200?km toward sodic dolomitic with the ~52?mol% Na2CO3 at 80-120?km depths.
DS201906-1336
2019
Arefiev, A.V.Podborodnikov, I.V., Shatskiy, A., Arefiev, A.V., Bekhtenova, A.New data on the system Na2CO3-CaCO3-MgCO3 at 6 Gpa with implications to the composition and stability of carbonatite melts at the base of continental lithosphere.Chemical Geology, Vol. 515, pp. 50-60.Russiadeposit - Udachnaya-East

Abstract: Subsolidus and melting phase relationships in the system Na2CO3-CaCO3-MgCO3 have been studied at 6?GPa and 900-1250?°C using a Kawai-type multianvil press. At 900 and 1000?°C, the system has four intermediate compounds: Na2Ca4(CO3)5 burbankite, Na2Ca3(CO3)4, Na4Ca(CO3)3, and Na2Mg(CO3)2 eitelite. The Na-Ca compounds dissolve noticeable amounts of Mg component, whereas eitelite dissolves a few percents of Ca component: Na2(Ca=0.91Mg=0.09)4(CO3)5, Na2(Ca=0.94Mg=0.06)3(CO3)4, Na4(Ca=0.67Mg=0.33)(CO3)3, and Na2(Mg=.93Ca=0.07)(CO3)2. At 1050?°C, the system is complicated by an appearance of dolomite. Na-Ca burbankite decomposes at 1075?±?25?°C to aragonite plus Na2Ca3(CO3)4. Na4Ca(CO3)3 and eitelite disappear via congruent melting between 1200 and 1250?°C. Na2Ca3(CO3)4 remains stable through the whole studied temperature range. The liquidus projection of the studied ternary system has eight primary solidification phase regions for magnesite, dolomite, calcite-dolomite solid solutions, aragonite, Na2Ca3(CO3)4, Na4Ca(CO3)3, and Na2CO3 solid solutions. The system has five ternary peritectic reaction points and one minimum on the liquidus at 1050?°C and 48Na2CO3•52(Ca0.75Mg0.25)CO3. The minimum point resembles a eutectic controlled by a four-phase reaction, by which a liquid transforms into three solid phases upon cooling: Na2(Ca0.94Mg0.06)3(CO3)4, Na4(Ca0.67Mg0.33)(CO3)3, and Na2(Mg0.93Ca0.07)(CO3)2 eitelite. Since at 6?GPa, the system has a single eutectic, there is no thermal barrier preventing continuous liquid fractionation from alkali-poor toward Na-rich dolomitic compositions. Cooling of the Na-Ca-Mg carbonatite melt from 1400 to 1100?°C within the lherzolite substrate will be accompanied by magnesite crystallization and wehrlitization keeping calcium number of the melt at 40 and shifting the Na2CO3 content to =40?mol%. In the case of the eclogitic wall rock, the cooling will be accompanied by dolomite crystallization keeping calcium number of the melt at 60-65 and shifting the Na2CO3 content to =30?mol%.
DS201908-1812
2019
Arefiev, A.V.Shatskiy, A., Arefiev, A.V., Podborodnikov, I.V., Litasov, K.D.Origin of K-rich diamond-forming immscible melts and CO2 fluid via partial melting of carbonated pelites at depth of 180-200 km.Gondwana Research, Vol. 75, pp. 154-171.Mantlediamond genesis

Abstract: Melt inclusions in kimberlitic and metamorphic diamonds worldwide range in composition from potassic aluminosilicate to alkali-rich carbonatitic and their low-temperature derivative, a saline high-density fluid (HDF). The discovery of CO2 inclusions in diamonds containing eclogitic minerals are also essential. These melts and HDFs may be responsible for diamond formation and metasomatic alteration of mantle rocks since the late Archean to Phanerozoic. Although a genetic link between these melts and fluids was suggested, their origin is still highly uncertain. Here we present experimental results on melting phase relations in a carbonated pelite at 6?GPa and 900-1500?°C. We found that just below solidus K2O enters potassium feldspar or K2TiSi3O9 wadeite coexisting with clinopyroxene, garnet, kyanite, coesite, and dolomite. The potassium phases react with dolomite to produce garnet, kyanite, coesite, and potassic dolomitic melt, 40(K0.90Na0.10)2CO3•60Ca0.55Mg0.24Fe0.21CO3?+?1.9?mol% SiO2?+?0.7?mol% TiO2?+?1.4?mol% Al2O3 at the solidus established near 1000?°C. Molecular CO2 liberates at 1100?°C. Potassic aluminosilicate melt appears in addition to carbonatite melt at 1200?°C. This melt contains (mol/wt%): SiO2?=?57.0/52.4, TiO2?=?1.8/2.3, Al2O3?=?8.5/13.0, FeO?=?1.4/1.6, MgO?=?1.9/1.2, CaO?=?3.8/3.2, Na2O?=?3.2/3.0, K2O?=?10.5/15.2, CO2?=?12.0/8.0, while carbonatite melt can be approximated as 24(K0.81Na0.19)2CO3•76Ca0.59Mg0.21Fe0.20CO3?+?3.0?mol% SiO2?+?1.6?mol% TiO2?+?1.4?mol% Al2O3. Both melts remain stable to at least 1500?°C coexisting with CO2 fluid and residual eclogite assemblage consisting of K-rich omphacite (0.4-1.5?wt% K2O), almandine-pyrope-grossular garnet, kyanite, and coesite. The obtained immiscible alkali-carbonatitic and potassic aluminosilicate melts resemble compositions of melt inclusions in diamonds worldwide. Thus, these melts entrapped by diamonds could be derived by partial melting of the carbonated material of the continental crust subducted down to 180-200?km depths. Given the high solubility of chlorides and water in both carbonate and aluminosilicate melts inferred in previous experiments, the saline end-member, brine, could evolve from potassic carbonatitic and/or silicic melts by fractionation of Ca-Mg carbonates/eclogitic minerals and accumulation of alkalis, chlorine and water in the residual low-temperature supercritical fluid. Direct extraction from the hydrated marine sediments under conditions of cold subduction would be another possibility for the brine formation.
DS201909-2085
2019
Arefiev, A.V.Shatskiy, A., Arefiev, A.V., Podborodnikov, I.V., Litasov, K.D.Origin of K-rich diamond forming immiscible melts and CO2 fluid via partial melting of carbonated pelites at a depth of 180-200km.Gondwana Research, Vol. 75, pp. 154-171.Mantlediamond genesis

Abstract: Melt inclusions in kimberlitic and metamorphic diamonds worldwide range in composition from potassic aluminosilicate to alkali-rich carbonatitic and their low-temperature derivative, a saline high-density fluid (HDF). The discovery of CO2 inclusions in diamonds containing eclogitic minerals are also essential. These melts and HDFs may be responsible for diamond formation and metasomatic alteration of mantle rocks since the late Archean to Phanerozoic. Although a genetic link between these melts and fluids was suggested, their origin is still highly uncertain. Here we present experimental results on melting phase relations in a carbonated pelite at 6?GPa and 900-1500?°C. We found that just below solidus K2O enters potassium feldspar or K2TiSi3O9 wadeite coexisting with clinopyroxene, garnet, kyanite, coesite, and dolomite. The potassium phases react with dolomite to produce garnet, kyanite, coesite, and potassic dolomitic melt, 40(K0.90Na0.10)2CO3•60Ca0.55Mg0.24Fe0.21CO3?+?1.9?mol% SiO2?+?0.7?mol% TiO2?+?1.4?mol% Al2O3 at the solidus established near 1000?°C. Molecular CO2 liberates at 1100?°C. Potassic aluminosilicate melt appears in addition to carbonatite melt at 1200?°C. This melt contains (mol/wt%): SiO2?=?57.0/52.4, TiO2?=?1.8/2.3, Al2O3?=?8.5/13.0, FeO?=?1.4/1.6, MgO?=?1.9/1.2, CaO?=?3.8/3.2, Na2O?=?3.2/3.0, K2O?=?10.5/15.2, CO2?=?12.0/8.0, while carbonatite melt can be approximated as 24(K0.81Na0.19)2CO3•76Ca0.59Mg0.21Fe0.20CO3?+?3.0?mol% SiO2?+?1.6?mol% TiO2?+?1.4?mol% Al2O3. Both melts remain stable to at least 1500?°C coexisting with CO2 fluid and residual eclogite assemblage consisting of K-rich omphacite (0.4-1.5?wt% K2O), almandine-pyrope-grossular garnet, kyanite, and coesite. The obtained immiscible alkali-carbonatitic and potassic aluminosilicate melts resemble compositions of melt inclusions in diamonds worldwide. Thus, these melts entrapped by diamonds could be derived by partial melting of the carbonated material of the continental crust subducted down to 180-200?km depths. Given the high solubility of chlorides and water in both carbonate and aluminosilicate melts inferred in previous experiments, the saline end-member, brine, could evolve from potassic carbonatitic and/or silicic melts by fractionation of Ca-Mg carbonates/eclogitic minerals and accumulation of alkalis, chlorine and water in the residual low-temperature supercritical fluid. Direct extraction from the hydrated marine sediments under conditions of cold subduction would be another possibility for the brine formation.
DS202009-1659
2020
Arefiev, A.V.Shatskiy, A., Arefiev, A.V.,Podborodnikov, I.V., Litasov, K.D.Liquid immiscibility and phase relations in the system KAlSi0308-CaMg ( CO3)2+- NaAiSi2O6+- Na2CO3 at Gpa: implications for diamond forming melts.Chemical Geology, Vol. 550, 17p. PdfMantlemelting

Abstract: To evaluate the effect of Na on the carbonate-silicate liquid immiscibility in the diamond stability field, we performed experiments along some specific joins of the system KAlSi3O8-CaMg(CO3)2 ± NaAlSi2O6 ± Na2CO3 at 6 GPa. Melting in all studied joins begins at 1000-1050 °C. The melting in the Kfs + Dol system is controlled by the reaction 6 KAlSi3O8 (K-feldspar) + 6 CaMg(CO3)2 (dolomite) = 2 (Can,Mg1-n)3Al2Si3O12 (garnet) + Al2SiO5 (kyanite) + 11 SiO2 (coesite) + 3 K2(Ca1-n,Mgn)2(CO3)3 (carbonatitic melt) + 3 CO2 (fluid), where n ~ 0.3-0.4. A temperature increasing to 1300 °C yields an appearance of the silicic immiscible melt in addition to carbonatitic melt via the reaction K2CO3 (carbonatitic melt) + Al2SiO5 (kyanite) + 5 SiO2 (coesite) = 2 KAlSi3O8 (silicic melt) + CO2 (fluid or solute in melts). The silicic melt composition is close to KAlSi3O8 with dissolved CaMg(CO3)2 and molecular CO2. An addition of NaAlSi2O6 or Na2CO3 to the system results in partial decomposition of K-feldspar and formation of K-bearing carbonates, (K, Na)2Mg(CO3)2 and (K, Na)2Ca3(CO3)4. Their melting produces carbonatite melt with the approximate composition of 4(K, Na)2CO3•6Ca0.6Mg0.4CO3 and magnesite. Besides, the presence of NaAlSi2O6 in the studied system shifts the lower-temperature limit of immiscibility to 1500°?, while the presence of Na2CO3 eliminates the appearance of silicic melt by the following reaction: 2 KAlSi3O8 (in the silicic melt) + Na2CO3 = 2 NaAlSi2O6 (in clinopyroxene) + K2CO3 (in the carbonatitic melt) + SiO2 (coesite). Thus, an increase of the Na2O content in the system Na2O-K2O-CaO-MgO-Al2O3-SiO2-CO2 consumes Al2O3 and SiO2 from silicic melt to form clinopyroxene. We found that grossular-pyrope and diopside-jadeite solid solutions can coexist with CO2 fluid at 900-1500 °C and 6 GPa. Thus, CO2 fluid is stable in the eclogitic suite in the diamond stability field under temperature conditions of the continental lithosphere and subducting slabs. Variations in the Na2O content observed in carbonatitic melts trapped by natural in diamonds exceed those derived by the pelite melting. The present experiments show that an addition of NaAlSi2O6 to the Kfs + Dol system does not cause an increase of the Na2O content in the carbonatitic melt, whereas the addition of Na2CO3 at Na2O/Al2O3 > 1 yields the formation of the melts with the Na2O contents covering the entire range of natural compositions. Thus, only the presence of additional salt components can explain the elevated Na2O content in the melts trapped in lithospheric diamonds. In addition to carbonates, sodium can be hosted by chlorides, sulfates, etc.
DS202009-1660
2020
Arefiev, A.V.Shatskiy, A., Bekhtenova, A., Podborodnikov, I.V., Arefiev, A.V., Litasov, K.D.Metasomatic interaction of the eutectic Na- and K-bearing carbonate melts with natural garnet lherzolite at 6 Gpa and 1100-1200 C: toward carbonatite melt composition in SCLM.Lithos, Vol. 374-375, 17p. PdfMantlemetasomatism

Abstract: The range of carbonatite melts in equilibrium with the subcontinental lithospheric mantle (SCLM) under geothermal conditions is limited by alkali-rich near-eutectic compositions. Therefore, here we employed eutectic Na/K-Ca-Mg-Fe carbonate mixtures to model the interaction of a metasomatic carbonatite melt with natural garnet lherzolite. The experiments were performed at 1100 and 1200 °C and 6 GPa in graphite capsules using a multianvil press. The run duration was 111 and 86 h, respectively. To verify achieving an equilibrium, a synthetic mixture identical to natural lherzolite was also employed. We have found that both Na- and K-bearing carbonatite melts cause wehrlitization accompanying by the elimination of orthopyroxene and an increase of CaO in garnet at a constant Cr2O3. Interaction with the K-carbonatite melt alters clinopyroxene composition toward lower Na2O (0.2-0.3 wt%), and higher K2O (0.5-1.0 wt%), whereas the Na-carbonatite melt revealed the opposite effect. The resulting melts have a following approximate composition [40(Na, K)2CO3·60Ca0.5Mg0.4Fe0.1CO2 + 0.6-1.4 wt% SiO2] displaying a decrease in Ca# at a nearly constant alkali content relative to the initial composition, where Ca# = 100·Ca/(Ca + Mg + Fe). We have also found that alkali-poor (= 20 mol% (Na, K)2CO3) carbonate mixtures do not melt completely but yield magnesite and alkali- and Ca-rich melts like those in the systems with eutectic mixtures. Under SCLM P-T conditions the range of carbonatite melt compositions is restricted by the full melting field of alkali-rich carbonates in the corresponding Na/K-Ca-Mg carbonate systems. Infiltration of less alkaline higher-temperature carbonatite melt in SCLM and its subsequent cooling to the ambient mantle temperature, 1100-1200 °C at 6 GPa, should cause crystallization of magnesite and shift the melt composition to [30(Na, K)2CO3·70Ca0.6Mg0.3Fe0.1CO3]. Owing to its high Ca#, this melt is not stable in equilibrium with orthopyroxene yielding its disappearance by CaMg exchange reaction producing clinopyroxene, magnesite, and shifting the melt composition toward higher alkali content. The melts containing 40-45 mol% of alkaline carbonates have no limitation in Ca# because the corresponding binary NaMg and KMg carbonate eutectics are located near 1200 °C. Therefore, these melts can achieve Ca# = 30-40 and, be in equilibrium with garnet lherzolites and harzburgites under the geothermal condition of SCLM. Considering the present results and previous experimental data the following ranges of carbonatite melt compositions can be expected in equilibrium with garnet peridotites at the base of SCLM: Ca# < 30 and > 30 mol% (K, Na)2CO3 in equilibrium with harzburgite; Ca# 30-40, >25 mol% (K, Na)2CO3 in equilibrium with lherzolite; and Ca# 40-60 and >20 mol% (K, Na)2CO3 in equilibrium with wehrlite.
DS202012-2250
2020
Arefiev, A.V.Shatskiy, A., Bekhtenova, A., Podbororodnikov, I.V., Arefiev, A.V.Carbonate melt interaction with natural eclogite at 6 Gpa and 1100-1200 C Implcations for metasomatic melt composition in subcontinental lithospheric mantle.Chemical Geology, Vol. 558, 119915, 15p. PdfMantlecarbonatite

Abstract: Compositional ranges of carbonate melts stable under P-T conditions corresponding to the base of subcontinental lithospheric mantle (SCLM) are limited by alkali-rich near-eutectic compositions. In the present work, we investigated the interaction of such melts with the natural eclogite of Group A. It was found that the interaction is accompanied by decreasing Ca# in the melt (L) and increasing Ca# in garnet (Grt) according to the reaction: 3CaCO3 (L) + Mg3Al2Si3O12 (Grt) = 3MgCO3 (Mgs and/or L) + Ca3Al2Si3O12 (Grt), where Mgs is magnesite. The interaction with the Na-Ca-Mg-Fe carbonate melt increases amount of jadeite component in clinopyroxene (Cpx) consuming Al2O3 from garnet and Na2O from the melt according to the reaction: Na2CO3 (L) + CaCO3 (L) + 2Mg3Al2Si3O12 (Grt) + 2CaMgSi2O6 (Cpx) = 2NaAlSi2O6 (Cpx) + Ca3Al2Si3O12 (Grt) + 2MgCO3 (Mgs, L) + 3Mg2SiO4 (Ol). As a result, garnet and omphacite compositions evolve from eclogite Group A to eclogite Group B. A byproduct of the reaction is olivine (Ol), which may explain the formation of inclusions of “mixed” eclogite (garnet + omphacite) and peridotite (olivine) paragenesis in lithospheric diamonds. The interaction with the K-Ca-Mg-Fe carbonate melt increases the K2O content in clinopyroxene to 0.5-1.2 wt%, while the Na2O content lowers to 0.3 wt%. The following range of carbonatite melt compositions can be in equilibrium with eclogite at the base of SCLM (1100-1200 °C and 6 GPa): 18(Na0.97K0.03)2CO3·82(Ca0.63Mg0.30Fe0.07)CO2-42(Na0.97K0.03)2CO3·58(Ca0.46Mg0.45Fe0.09)CO2. Our results also suggest that the partial melting of ‘dry’ carbonated eclogite, if any, at 1100 °C and 6 GPa yields the formation of a carbonate melt with the following composition (mol%) 25(Na0.96K0.04)2CO3·75(Ca0.64Mg0.31Fe0.05)CO2, corresponding to 18-27 wt% Na2O in the melt on a volatile-free basis.
DS1970-0234
1971
Arem, J.E.Arem, J.E.The Curse of the Million Dollar DiamondRock And Gem., SEPT.-Oct. PP. 76-78.IndiaDiamonds Notable, Hope
DS1970-0625
1973
Arem, J.E.Arem, J.E.Man Made CrystalsWashington: Smithsonian Institute Press, 109P.GlobalKimberlite, Synthetic, Kimberley, Diamond
DS200912-0009
2009
Arem, J.E.Arem, J.E.New gemstone treatments - a coming crisis. Overview of treatments - more specific to range of all gemstones (not diamonds in particular). Scientific explanationsColored Stone Magazine, Vol. 22, May-June, 15p.TechnologyGemstone treatments
DS201901-0003
2018
Aremieva, I.M.Aremieva, I.M., Thybo, H., Cherepanova, Y.Isopycnicity of cratonic mantle restricted to kimberlite provinces.Earth and Planetary Science Letters, Vol. 505, pp. 162-172.Russia, Siberiacraton

Abstract: The isopycnicity hypothesis states that the lithospheric mantle of ancient platforms has a unique composition such that high density due to low lithosphere temperature is nearly compensated by low-density composition of old cratonic mantle. This hypothesis is supported by petrological studies of mantle xenoliths hosted in kimberlite magmas. However, the representativeness of the kimberlite sampling may be questioned, given that any type of magmatism is atypical for stable regions. We use EGM2008 gravity data to examine the density structure of the Siberian lithospheric mantle, which we compare with independent constraints based on free-board analysis. We find that in the Siberian craton, geochemically studied kimberlite-hosted xenoliths sample exclusively those parts of the mantle where the isopycnic condition is satisfied, while the pristine lithospheric mantle, which has not been affected by magmatism, has a significantly lower density than required by isopycnicity. This discovery allows us to conclude that our knowledge on the composition of cratonic mantle is incomplete and that it is biased by kimberlite sampling which provides a deceptive basis for the isopycnicity hypothesis.
DS1983-0106
1983
Arens, V.Z.Arens, V.Z., Kuritsyn, L.I., Lokhova, T.D.Study of the Scope for Chemical Softening of KimberlitesSoviet Mining, Vol. 19, No. 6, PP. 528-531.RussiaBlank
DS201312-0705
2013
Arenson, L.U.Pham, N.H., Sego, D.C., Arenson, L.U., Blowes, D.W., Amos, R.T., Smith, L.The Diavik waste rock project: measurement of the thermal regime of a waste rock test pile in a permafrost environment.Applied Geochemistry, Vol. 36, pp. 234-245.Canada, Northwest TerritoriesMining - Diavik
DS2002-0281
2002
ArestovaChekulaev, V.P., Lobach-Zhuchenko, S.B., ArestovaArchean magmatism in the northwestern margin of the ancient Vodlozero domain near Lake Oster: geology...Petrology, Vol.10,2,pp.119-45.Russia, KareliaGeology, geochemistry, petrology, Magmatism
DS1998-0889
1998
Arestova, N.A.Lobach Zhuchenko, S.b., Arestova, N.A., Kyslov, I.N.Geochemistry and petrology of 2.40 - 2.45 Ga magmatic rocks in northwestern Belomorian Belt, FennoscandiaPrecamb. Res., Vol. 92, No. 3, Nov. pp. 223-50.Russia, FennoscandiaBelomorian Belt, Magmatism
DS200512-0653
2004
Arestova, N.A.Lobach-Zhuchenko, S.B., Rollinson, H.R., Chekulaev, V.P., Arestova, N.A., Kovalenko, A.V., IvanikovThe Archean sanukitoid series of the Baltic Shield: geological setting, geochemical characteristics and implications for their origin.Lithos, Vol. 79, pp. 107-128.Baltic Shield, Kola Peninsula, RussiaGeneral regional geology, lamprophyres
DS200612-0910
2006
Arestova, N.A.Mertanen, S., Vuollo, J.I., Huhma, H., Arestova, N.A., Kovalenko, A.Early Paleoproterozoic Archean dykes and gneisses in Russian Karelia of the Fennoscandian Shield - new paleomagnetic, isotope age, geochemical investigations.Precambrian Research, Vol. 144, 3-4, Feb. 10, pp. 239-260.Russia, Europe, Finland, Sweden, Kola PeninsulaGeochronology
DS200812-0681
2008
Arestova, N.A.Lobach Zhuchenko, S.B., Rollinson, H., Chekulaev, V.P., Savatenkov, V.M., Kovalenko, A.V., Martin, H., Guseva, N.S., Arestova, N.A.Petrology of Late Archean, highly potassic, sanuktoid pluton from the Baltic Shield: insights into Late Archean mantle metasomatism.Journal of Petrology, Vol. 49, 3, pp. 393-420.Europe, Baltic shieldMetasomatism
DS2002-1502
2002
Arevalo, A.Skewes, M.A., Arevalo, A., Floody, Zuniga, SternThe giant El Teniente breccia deposit: hypogene copper distribution and emplacementSociety of Economic Geologists Special Publication, No.9,pp.299-332.ChileCopper, metallogeny, Deposit - El Teniente
DS201808-1780
2018
Arevalo, Jr. R.Putirka, K., Tao, Y., Hari, K.R., Perfit, M., Jackson, M.G., Arevalo, Jr. R.The mantle source of thermal plumes: trace and minor element & major oxides of primitive liquids ( and why olivine compositions don't matter).minoscam.org, doi.org/10.2138/am-2018-6192 59p.Mantleforsterite

Abstract: We estimate the mantle source compositions for mantle plumes, and by implication Earth’s lower mantle, by: (a) measuring trace (e.g, Sc, V, Cu) and minor (e.g., Ca, Mn, Ni) element concentrations of high forsterite olivine grains from several plume localities, (b) estimating the parent liquid compositions from which they crystallized, (c) calculating mantle potential temperatures and degrees of partial melting and (d) estimating trace element compositions of depleted and enriched mantle sources. Our sample set includes two continental flood basalt provinces (Emeishan and Deccan), a flood basalt that erupted in a continental rift setting (Baffin Island), our type example of a thermal mantle plume (Hawaii) and lavas from the Siqueiros Transform at the East Pacific Rise, which represent the mid-ocean ridge system. We also present olivine compositions for the peridotite xenoliths from Kilbourne Hole, New Mexico, USA, which are commonly used as primary and secondary analytical standards. We find that trace elements in lava-hosted olivine grains are too far removed from their mantle source to provided anything but greatly hindered views of such. Olivine compositions reflect not only evolving liquid compositions (including partial melting conditions and later fractionation), but also evolving Ol+liq partition coefficients, which mostly increase with decreasing T during crystallization. Mantle compositions, delimited by maximum forsterite contents and estimates of parental magmas (and experimentally determined partition coefficients) indicate that our selected plumes reflect some combination of (1) a depleted mantle source that is quite similar to that obtained by other methods, and (2) a variably enriched plume source that is more enriched than current estimates of pyrolite. The enriched plume mantle sources can be explained remarkably well as a mixture of subducted mid-ocean ridge basalt (MORB; Gale et al. 2013) and depleted MORB mantle (DM; Salters and Stracke 2004), with MORB:DM ratios of 1:5 to 1:4. These ratios are most sensitive to estimates of melt fraction where plume parental magmas are last equilibrated with their mantle source, but are nonetheless consistent across a wide range of chemically very different elements, and estimates of MORB and DM obtained by very different means. Baffin Island is of particular interest. Like prior studies, we verify a high mantle potential temperature (Tp) of 1630oC (compared to Tp = 1320-1420oC for MORB from Cottrell and Kelley 2011 for Ol of Fo89.3-91.4). The Baffin source is also within error the same as DM with respect to trace elements, although still isotopically distinct; Baffin appears to be sourced in something that is akin to DM that lies at the base of the mantle, where plumes acquire their excess heat. Thus while part of our analysis supports the concept of a "slab graveyard" at the bottom of the lower mantle (e.g., Wyession 1996), that cemetery is by no means ubiquitous at the CMB: subducted slabs are either unevenly interred, or efficiently excavated by later upwellings.
DS200912-0010
2009
Arevalo, R.Arevalo, R., McDononough, W.F., Luong, M.The K/U ratio of the silicate Earth: insights into mantle composition, structure and thermal evolution.Earth and Planetary Science Letters, Vol. 278 3-4, pp. 361-369.MantleGeothermometry
DS200612-0890
2006
Arevalo, R.D.McDononough, W.F., Arevalo, R.D.Crust mantle and core mantle recycling.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 30. abstract only.MantleSubduction
DS200812-0732
2008
Arevalo, R.J.McDonough, W.F., Arevalo, R.J.Mantle convection and K/U.Goldschmidt Conference 2008, Abstract p.A613.MantleConvection
DS200912-0014
2009
Arezamastseva, L.V.Arzamastsev, A.A., Arezamastseva, L.V., Zhirova, A.M.The alkaline polyphase plutons in the NE Fennoscandian Shield, Russia: deep structure and duration of magmatism.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractRussia, Kola PeninsulaLovozero
DS1993-0038
1993
Argentina Investment Opportunity ConferenceArgentina Investment Opportunity ConferenceMining : Provinces examples...metalifferous informationArgentina Investment Opprtunity Conference held Denver, Spring 1993, 20pArgentinaLegal, Metallogeny
DS1993-0039
1993
Argentina Investment Opportunity ConferenceArgentina Investment Opportunity ConferenceNew legal framework of Argentin a mining policyArgentina Investment Opprtunity Conference held Denver, Spring 1993, 23pArgentinaLegal, Mining policy
DS1993-0040
1993
Argentina Investment Opportunity ConferenceArgentina Investment Opportunity ConferenceOverview of the country statisticsArgentina Investment Opprtunity Conference held Denver, Spring 1993, 10pArgentinaLegal, Statistics, population, railroads, transportation
DS1960-0630
1966
Argenzio, V.Argenzio, V.The Fascination of DiamondsLondon: Allen And Unwin., 101P.South Africa, GlobalKimberley, History
DS1970-0872
1974
Argenzio, V.Argenzio, V.Diamonds EternalNew York: Mckay, 290P.GlobalKimberlite, Kimberley, Janlib, Gemology
DS1975-0453
1977
Argenzio, V.Argenzio, V.Crystal Clear, the Story of DiamondsNew York: Mckay, Criterion Press, 51P.GlobalKimberlite, Kimberley, Janlib, Gemology
DS200512-1000
2005
Arghe, F.Skeleton, A., Whitmarsh, R., Arghe, F., Crill, P., Koyi, H.Constraining the rate and extent of mantle serpentinization from seismic and petrological data: implications for chemosynthesis and tectonic processes.Geofluids, Vol. 5, 3, pp. 153-164.MantleGeophysics - seismics
DS200512-1001
2005
Arghe, F.Skelton, A., Whitmarsh, R., Arghe, F., Crill, P., Koyi, H.Constraining the rate and extent of mantle serpentinization from seismic and petrological data: implications for chemosynthesis and tectonic processes.Geofluids, Vol. 5, 3, pp. 153-164.MantleGeophysics - seismics, tectonics
DS200712-0995
2007
Arghe, F.Skelton, A., Vuorinen, J.H., Arghe, F., Fallick, A.Fluid rock interaction at a carbonatite gneiss contact, Alno Sweden.Contributions to Mineralogy and Petrology, Vol. 154, 1, pp.75-90.Europe, SwedenCarbonatite
DS201112-0763
2011
Argles, T.Osborner, I., Sherlock, S., Anand, M., Argles, T.New Ar-Ar ages of southern Indian kimberlites and a lamproite and their geochemical evolution.Precambrian Research, Vol. 189, pp. 91-103.IndiaGeochronology
DS1997-0125
1997
Argunov, K.Bratus, M.D., Zinchuk, N.N., Svoren, I.M., Argunov, K.Gases from Yakutian polycrystalline diamondsDoklady Academy of Sciences, Vol. 355, No. 5, Jun-July pp. 757-9.Russia, YakutiaDiamond inclusions
DS1970-0023
1970
Argunov, K.P.Argunov, K.P., Bartoshinsky, Z.V.Luminescence Characteristics of Diamonds from KimberlitesMineral. Sb. L'vov Gos University, No. 24, PP. 185-190.RussiaBlank
DS1980-0038
1980
Argunov, K.P.Argunov, K.P., Botkunov, A.I., et al.Small Diamonds of Cubic Habit from Kimberlites of YakutiaTsnigri, No. 153, PP. 75-79.RussiaBlank
DS1982-0070
1982
Argunov, K.P.Argunov, K.P., Zuyev, V.M., Nikiforova, T.M., Prishchepa, V.I.Sculptures of Corrosion of Crystal Regeneration in DiamondsMineral. Zhurnal, Vol. 4, No. 3, PP. 66-70.RussiaMineralogy, Surface Defects
DS1983-0107
1983
Argunov, K.P.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
DS1983-0324
1983
Argunov, K.P.Ivankin, P.F., Argunov, K.P., Boris, Y.I.Evolution of the Formation Conditions of Diamonds in Kimberlites.(russian)Sov. Geol., (Russian), No. 9, pp. 30-38RussiaDiamond Morphology
DS1985-0023
1985
Argunov, K.P.Argunov, K.P., Zinchuk, N.N., Zuyev, V.M., Kvasnitsa, V.N.Carbonado and Imperfect Crystals Among Small Diamonds from kimberlites.Mineral. Zhurn., Vol. 7, No. 2, PP. 95-96.RussiaMineralogy, Microdiamonds
DS1985-0093
1985
Argunov, K.P.Bulanova, G.P., Argunov, K.P.Potassium feldspar inclusions in diamond crystal from the Mirkimberlitepipe. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR.(Russian), Vol. 284, No. 4, pp. 953-956RussiaDiamond Morphology
DS1985-0094
1985
Argunov, K.P.Bulanova, G.P., Argunov, K.P.Potassium Feldspar Inclusions in Diamond Crystal from the Mir Kimberlite Pipe.Doklady Academy of Sciences Nauk SSSR., Vol. 284, No. 4, PP. 953-956.RussiaMir, Inclusions, Mineralogy
DS1985-0304
1985
Argunov, K.P.Ivankin, P.F., Argunov, K.P., Boris, YE.I.Changing Environments of Diamond Formation in KimberlitesInternational Geology Review, Vol. 26, No. 7, PP. 795-802.RussiaGenesis
DS1985-0549
1985
Argunov, K.P.Prokopchuk, B.I., Argunov, K.P., Boris, Y.I., Zazhardova, V.R.Seperation of Diamonds in Placer Deposits. (russian)Soviet Geology, (Russian), No. 3, pp. 43-57RussiaPlacers
DS1986-0539
1986
Argunov, K.P.Mazykin, V.V., Mattyash, I.V., Kvasnitska, V.N., Argunov, K.P., ZinchukESR spectra of neutron irradiated diamonds.(Russian)Dopl. Akad. Nauk UKR. B.Geol, (Russian), No. 10, pp. 10-12GlobalMineralogy
DS1987-0082
1987
Argunov, K.P.Bulanova, G.P., Argunov, K.P.Potassic feldspar inclusions in a diamond crystal from the Mir pipeDoklady Academy of Science USSR, Earth Science Section, Vol. 284, No. 5, Publishing July 1987, pp. 158-161RussiaMineralogy
DS1988-0321
1988
Argunov, K.P.Ivankin, P.F., Argunov, K.P., Boris, Ye.I.Stages of kimberlite development and evolving conditions of diamondformationInternational Geology Review, Vol. 30, no, . 3, March pp. 268-274RussiaDiamond morphology, Diamond genesis
DS1990-0234
1990
Argunov, K.P.Bratus, M.D., Zinchuk, N.N., Argunov, K.P., Svoren, Y.M.Composition of fluid inclusions in Yakutian diamond crystals.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 4, August pp. 49-56RussiaDiamond morphology, Diamond inclusions
DS1991-0166
1991
Argunov, K.P.Bratus, M.D., Svoren, I.M., Zinchuk, N.N., Argunov, K.P.Fluid inclusion gas components in the different morphological types Of diamonds from Yakutia.(Russian)Geochemistry International (Geokhimiya), (Russian), No. 11, pp. 1586-1595Russia, YakutiaDiamond morphology, Geochemistry, inclusions
DS1992-0158
1992
Argunov, K.P.Bratus, M.D., Svoren, Y.M., Zinchuk, N.N., Argunov, K.P.Gas components of inclusions in Yakutian diamondsGeochemistry International, Vol. 29, No. 6, pp. 69-78Russia, YakutiaDiamond inclusions, Geochemistry
DS1987-0147
1987
Argus, D.F.DeMets, C., Gordon, R.G., Stein, S., Argus, D.F.A revised estimate of Pacific North America motion And implications for western North America plate boundary zonetectonicsGeophysical Research Letters, Vol. 14, No. 9, September pp. 911-914CordilleraTectonics
DS1991-0030
1991
Argus, D.F.Argus, D.F., Gordon, R.G.Current Sierra Nevada -North America motion from very long baselineinterferometery: implications for the kinematics of the western United StatesGeology, Vol. 19, No. 11, November pp. 1085-1088CordilleraTectonics, Geodynamics
DS201012-0148
2010
Argus, D.F.DeMets, C., Gordon, R.G., Argus, D.F.Geologically current plate motions.Geophysical Journal International, Vol. 181, 1, pp. 1-80.MantleGeodynamics - review tectonics
DS201212-0022
2012
Argus, D.F.Argus, D.F.Uncertainty in the velocity between the mass center and surface of Earth.Journal of Geophysical Research, Vol. 117, B 10, B10405MantleGeophysics - seismics
DS1990-0125
1990
Arik, A.Arik, A.Effects of search parameters on kriged reserve estimates #2American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, No. 90-48, 11pGlobalGeostatistics, Kriging
DS1990-0126
1990
Arik, A.Arik, A.Effects of search parameters on kriged reserve estimates #1International Journal of Mining and Geological Engineering, Vol. 8, pp. 305-318GlobalGeostatistics, Ore reserves
DS1993-0593
1993
Arik, A.Guocheng Pan, Arik, A.Restricted kriging for mixture of grade modelsMathematical Geology, Vol. 25, No. 6, August pp. 713-736GlobalGeostatistics, Ore reserves, grades
DS1998-0040
1998
Arik, A.Arik, A.Nearest neighbour kriging: a solution to control the smoothing of KrigedestimatesSociety for Mining, Metallurgy and Exploration (SME) Preprint, No. 98-73GlobalGeoststistics, Kriging
DS1985-0398
1985
Arima, A.M.Lloyd, F.E., Arima, A.M., Edgar, A.D.Partial Melting of a Phlogopite Clinopyroxenite Nodule: an Experimental Study on the Origin of High Pressureotassic Rocks.Geological Association of Canada (GAC)., Vol. 10, P. A35, (abstract.).GlobalExperimental Petrology
DS200412-1461
2004
Arima, H.Ohtaka, O., Shimono, M., Ohnisi, N., Fukui, H., Takebe, H., Arima, H., Yamanaka, T.,Kikegawa, T., Kume, S.HIP production of a diamond/ SiC composite and application to high pressure anvils.Physics of the Earth and Planetary Interiors, Vol. 143-144, pp. 587-591.TechnologyUHP
DS201805-0968
2018
Arima, H.Ono, K., Harada, Y., Yoneda, A., Yamamoto, J., Yoshiasa, A., Sugiyama, K., Arima, H., Watanabe, T.Determination of elastic constants of single crystal chromian spinel by resonant ultrasound spectroscopy and implications for fluid inclusion geobarometry.Physics and Chemistry of Minerals, Vol. 45, 3, pp. 237-247.Technologyxenolths

Abstract: We determined elastic constants of a single-crystal chromian spinel at temperatures from -15 to 45 °C through the Rectangular Parallelepiped Resonance method. The sample is a natural chromian spinel, which was separated from a mantle xenolith. Elastic constants at an ambient temperature (T = 24.0 °C) are C 11 = 264.8(1.7) GPa, C 12 = 154.5(1.8) GPa and C 44 = 142.6(0.3) GPa. All the elastic constants decrease linearly with increasing temperature. The temperature derivatives are dC 11/dT = -0.049(2) GPa/°K, dC 12/dT = -0.019(1) GPa/°K and dC 44/dT = -0.020(1) GPa/°K. As an implication of the elastic constants, we applied them to the correction of a fluid inclusion geobarometry, which utilizes residual pressure of fluid inclusion as a depth scale. Before entrainment by a magma, the fluid inclusions must have the identical fluid density in constituent minerals of a xenolith. It has been, however, pointed out that fluid density of fluid inclusions significantly varies with host mineral species. The present study elucidates that elastic constants and thermal expansion coefficients cannot explain the difference in fluid density among mineral species. The density difference would reflect the difference in the degree of plastic deformation in the minerals.
DS1980-0039
1980
Arima, M.Arima, M., Edgar, A.D.Stability of Wadeite ( Zr2 K4 Si6 O18) Under Upper Mantle Conditions: petrological Implications.Contributions to Mineralogy and Petrology, Vol. 72, No. 2, PP. 191-196.AustraliaLeucite, Lamproite, Petrochemistry
DS1980-0040
1980
Arima, M.Arima, M., Edgar, A.D.Stability of Wadeite (zr2 K4si6o18) Under Upper Mantle Conditions: Petrological Implications.Contributions to Mineralogy and Petrology, Vol. 72, PP. 191-195.United States, Wyoming, AustraliaLeucite
DS1980-0203
1980
Arima, M.Kuehner, S.M., Edgar, A.D., Arima, M.Origin of the Ultrapotassic Rocks from the Leucite Hills, Wyoming.Geological Society of America (GSA), Vol. 12, No. 7, P. 467. (abstract.).United States, Wyoming, Rocky Mountains, Leucite HillsLeucite Hills, Leucite, Rocky Mountains
DS1981-0067
1981
Arima, M.Arima, M., Edgar, A.D.Substitution Mechanisms and Solubility of Titanium in Phlogopites from Rocks of Probable Mantle Origin.Contributions to Mineralogy and Petrology, Vol. 77, PP. 288-295.Australia, United States, WyomingLeucite
DS1981-0255
1981
Arima, M.Kuehner, S.M., Edgar, A.D., Arima, M.Petrogenesis of the Ultrapotassic Rocks from the Leucite Hills, Wyoming.American Mineralogist., Vol. 66, No. 7-8, PP. 663-677.United States, Wyoming, Rocky Mountains, Leucite HillsBlank
DS1983-0108
1983
Arima, M.Arima, M., Edgar, A.D.A High Pressure Experimental Study on a Magnesian Rich Leucite Lamproite from the West Kimberley Area, Australia: Petrogenetic Implications.Contributions to Mineralogy and Petrology, Vol. 84, No. 2-3, PP. 228-234.Australia, Western AustraliaRelated Rocks, Petrography, Petrology, Wolgidite, Mineral Chemitry
DS1983-0109
1983
Arima, M.Arima, M., Edgar, A.D.high pressure EXPERIMENTAL STUDIES ONA KATUNGITE and THEIR BEARING on the GENESIS of SOME POTASSIUM RICH MAGMAS of the WEST BRANCH of the AFRICAN RIFT.Journal of PETROLOGY, Vol. 24, PT. 2, PP. 166-187.Central Africa, UgandaMineral Chemistry, Mafurite
DS1983-0211
1983
Arima, M.Edgar, A.D., Arima, M.Conditions of Phlogopite Crystallization in Ultrapotassic Volcanic Rocks.Mineralogical Magazine., Vol. 47, MARCH PP. 11-19.United States, Wyoming, Germany, California, West Coast, Australia, Spain, UgandaLeucite
DS1984-0138
1984
Arima, M.Barnett, R.L., Arima, M., Blackwell, J.D., Winder, C.G., Palmer.The Picton and Varty Lake Ultramafic Dikes: Jurassic Magmatism in the St. Lawrence Platform Near Belleville, Ontario.Canadian Journal of EARTH. SCI., Vol. 21, No. 12, DECEMBER PP. 1460-1472.Canada, OntarioBlank
DS1984-0139
1984
Arima, M.Barnett, R.L., Arima, M., Blackwell, WINDER, Palmer.The Picton and Varty lake ultramafic dikes: Jurassic magmatism in the St.Lawrence platform near BellevilleCanadian Journal of Earth Sciences, Vol. 21, pp. 1460-72.OntarioLamprophyre, Kimberlite, Deposit - Varty, Picton
DS1984-0254
1984
Arima, M.Edgar, A.D., Arima, M.Experimental Studies on K Metasomatism of a Model Pyrolite Mantle and Their Bearing on the Genesis of Ultrapotassic Magmas.Petrology (igneous And Metamorphic Rocks), 27th. International Geol., Vol. 9, PP. 509-541.GlobalKimberlite Nodules
DS1984-0255
1984
Arima, M.Edgar, A.D., Arima, M.Experimental studies on K metasomatism of a model pyrolite mantle and their bearing on the genesis of ultrapotassic magmasIn: Proceedings of the 27th. International Geological Congress held Moscow, August, pp. 509-542GlobalMantle
DS1985-0024
1985
Arima, M.Arima, M., Fleet, M.E., Barnett, R.L.Titanium Berthierine: a Ti Rich Serpentine Group Mineral From the Picton Ultramafic Dyke, Ontario.Canadian Mineralogist., Vol. 23, PT. 2, PP. 213-220.Canada, OntarioUltramafic Dike, Microscopy, Analyses
DS1985-0169
1985
Arima, M.Edgar, A.D., Arima, M.Fluorine and Chlorine Contents of Phlogopites Crystallized from ultrapotassic Rock Compositions in High Pressure Experiments- Implications for halogen Reservoirs in Source Regions.American MINERALOGIST., Vol. 70, No. 5-6, PP. 529-536.Canada, Ontario, United States, State Line, Wyoming, Leucite Hills, UgandaPetrology Wolgidite
DS1985-0170
1985
Arima, M.Edgar, A.D., Arima, M.Fluorine and Chlorine Contents of Phlogopites in High Pressure Melting experiments on Ultrapotassic Rocks: Implications for Fluorine and Chlorine rservoirs in Mantle Source Regions.Geological Association of Canada, Vol. 10, P. A 16, (abstract.).GlobalExperimental Petrology
DS1986-0026
1986
Arima, M.Arima, M., Barnett, R.L., Kerrich, R.Chemical and textural variations of mica in the Nickila Lake and Upper Canada mine kimberlites, OntarioProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 15-17OntarioUpper Canada mine
DS1986-0205
1986
Arima, M.Edgar, A.D., Arima, M., Baldwin, D.K., Bell, D.R., Shee, S.R., Skinner, E.M.high pressure melting experiments on an aphanitic kimberlite from the Wesselton mine, Kimberley South AfricaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 170-172South AfricaBlank
DS1988-0015
1988
Arima, M.Arima, M.Barium rich phlogopite in a mantle derived xenolith of the Upper Canada mine kimberlite, Ontario, Canada;implications for BA- reservoir in the uppermantleJournal of Japanese Association of Mineralogists, Petrologists and Economic, Vol. 83, No. 6, pp. 217-231OntarioPetrology, Upper Canada -Inclusions
DS1988-0016
1988
Arima, M.Arima, M., Kerrich, R.Jurassic kimberlites from Picton and Varty Lake,Ontario-geochemical and stable isotopiccharacteristicsContributions to Mineralogy and Petrology, Vol. 99, No. 3, pp. 385-391OntarioPicton-Varty Lake, Geochemistry
DS1988-0188
1988
Arima, M.Edgar, A.D., Arima, M., Baldwin, D.K., Bell, D.R., Shee, S.R.High-pressure-high temperature melting experiments on a SiO2poor aphanitic kimberlite from the Wesselton mine, Kimberley,South AfricaAmerican Mineralogist, Vol. 73, No. 5-6 May June pp. 524-533South AfricaBlank
DS1992-1713
1992
Arima, M.Yamashita, H., Arima, M.Melting experiment of group II kimberlites up to 10 GPa: petrogenesis Of kimberlite magmaProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 2, abstract p. 538GlobalExperimental petrology, Kimberlites
DS1993-0041
1993
Arima, M.Arima, M., Nakayama, K., Akaishi, M., Yamaoka, S., Kanda, H.Crystallization of diamond from a silicate melt of kimberlite composition in high temperature and high pressure experiments.Geology, Vol. 21, No. 11, November pp. 968-970.GlobalDiamond genesis, Experimental petrology
DS1994-0062
1994
Arima, M.Arima, M., Yamashita, H., Ohtani, E.Melting experiments of kimberlite up to 8GPa and its bearing onMetasomatismGeological Association of Canada (GAC) Abstract Volume, Vol. 19, p.GlobalPetrology - experimenta, Metasomatism
DS1995-0055
1995
Arima, M.Arima, M., Inoue, M.high pressure experimental study on growth and resorption of diamond In kimberlite melt.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 8-10.South AfricaPetrology -experimental, Deposit -Wesselton
DS1995-0056
1995
Arima, M.Arima, M., Presnall, D.C.Melting experiments on the join diopside magnesite at 7 GPa and their bearing on the genesis of kimb. magmas.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 11-13.GlobalPetrology -experimental, Kimberlite genesis
DS1995-2096
1995
Arima, M.Yamashita, H., Arima, M., Ohtani, E.high pressure melting experiments on group II kimberlite up to 8 GPa:implications MetasomatismProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 669-691.GlobalPetrology -experimental, Group II kimberlite
DS1998-0041
1998
Arima, M.Arima, M.Experimental study of growth and resorption of diamond in kimberlitic melt sat high pressures and temperatures7th International Kimberlite Conference Abstract, pp. 32-4.GlobalDiamond genesis, Experimental petrology - diamond inclusions
DS1998-1609
1998
Arima, M.Yamashita, H., Arima, M., Ohtani, E.Melting experiments of kimberlite compositions up to 9 GPa: determination of melt compositions using aggregate7th International Kimberlite Conference Abstract, pp. 977-9.GlobalExperimental petrology, Mineral chemistry
DS2000-0750
2000
Arima, M.Pati, J.K., Arima, M., Gupta, A.K.Experimental study of the system diopside - albite - nepheline at 2 and 10Kbar and at P (total) 28 Kbar.Canadian Mineralogist, Vol. 38, pt. 5, Oct. pp. 1177-91.MantlePetrology - experimental, Nepheline
DS2002-0057
2002
Arima, M.Arima, M., Kozai, Y., Akaishi, M.Diamond nucleation and growth by reduction of carbonate melts under high pressure and high temperature conditions.Geology, Vol.30,8,Aug.pp.691-4.MantleGenesis - diamond morphology
DS2003-0746
2003
Arima, M.Kozai, Y., Arima, M.Diamond dissolution in kimberlite and lamproite melts at deep crustal conditions8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractSouth AfricaDiamonds, Deposit - Wesselton, Mount North
DS200512-0576
2005
Arima, M.Kozai, Y., Arima, M.Experimental study on diamond dissolution in kimberlitic and lamproitic melts at 1300 - 1420C and 1 GPa with controlled oxygen partial pressure.American Mineralogist, Vol. 90, Nov-Dec. pp. 1759-1766.Africa, South Africa, AustraliaWesselton, Mount North, diamond morphology
DS200612-0035
2006
Arima, M.Arima, M., Kozar, Y.Growth and resorption of diamond by redox reactions in kimberlitic and carbonatitic melts.International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p. 138.MantleDiamond morphology - redox
DS200612-0742
2005
Arima, M.Kozai, Y., Arima, M.Experimental study on diamond dissolution in kimberlitic and lamproitic melts at 1300 - 1420 C and 1 GPa with controlled oxygen partial pressure.American Mineralogist, Vol. 90, pp. 1759-1766.Africa, South Africa, AustraliaWesselton, Mount North, melt solubility
DS200812-0042
2008
Arima, M.Arima, M., Koozai, Y.Diamond dissolution rates in kimberlitic melts at 1300-1500 C in the graphite stability field.European Journal of Mineralogy, Vol. 20, no. 3, 357-364.TechnologyMelting
DS201112-0098
2011
Arima, M.Bose, S., Dunkley, D.J., Dasgupta, S., Das, K., Arima, M.India-Antarctica-Australia-Laurentia connection in the Paleoproterozoic-Mesoproterozoic revisited: evidence from new zircon U Pb and monzazite chemical age dataGeological Society of America Bulletin, Vol. 123, 9/10 pp. 2031-2049.IndiaEastern Ghats Belt, geochronology
DS1986-0027
1986
Arima, N.Arima, N., Barnett, R.L., Hayatsu, A., Kerrich, R.A new kimberlite occurrence at Nickila Lake, Abitibi Greenstone belt; petrology, geochemistry and isotopic characteristicsGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 42. (abstract.)OntarioKirkland Lake, Diatreme, Geochonology
DS1985-0680
1985
Arima. m.Trones, R.G., Edgar, A.D., Arima. m.Titanium Solubility in Phlogopite: an Experimental Study On its Potential As a P-t Indicator for Upper Mantle- Lower Crustal Rocks.Geological Association of Canada (GAC)., Vol. 10, P. A 63, (abstract.).GlobalExperimental Petrology
DS201701-0020
2016
Arimoto, T.Liu, Z., Du, W., Shinmei, T., Greaux, S., Zhou, C., Arimoto, T., Kunimoto, T., Irifune, T.Garnets in the majorite pyrope system: symmetry, lattice microstain, and order-disorder of cations.Physics and Chemistry of Minerals, in press available 9p.TechnologyGarnet morphology

Abstract: We present a systematic experimental study on the phase transition, lattice microstrain, and order-disorder of cations for garnets in the majorite-pyrope system. Polycrystalline gem-quality garnets were synthesized at high pressure and high temperature using a Kawai-type multi-anvil apparatus. A phase transition from a cubic to tetragonal structure is clearly observed for garnets with the majorite content of more than 74 mol % through X-ray diffraction (XRD) and Raman scattering studies. Microstrain of garnets, evaluated with the Williamson-Hall plot on XRD profiles, shows a nonlinear dependence of the garnet compositions. The variation of the XRD peak broadening suggests the lattice microstrain of these garnets may be associated with the local structural heterogeneities due to the substitution of different cations via the coupled substitution (Mg2+ + Si4+ = 2Al3+) in the garnet structure. The width variation of Raman scattering peaks indicates that cation disorder occurs in the garnet structure for intermediate compositions. It is found that intermediate garnets and end-members have a minimum of microstrain, while those between end-members and intermediate compositions possess a larger microstrain.
DS1988-0017
1988
Arioglu, E.Arioglu, E.Examination of empirical formulae for predicting optimum mine outputTransactions of the Institute of Mining and Metallurgy (IMM), Vol. 97, No. A, July p. 160. *note only 1 pageGlobalGeostatistics, Ore Reserves
DS1985-0025
1985
Ariovich, G.Ariovich, G.The Economics of Diamond Price MovementManagement Decisions, Vol. 6, No. 4, December pp. 234-240GlobalEconomics
DS2001-0041
2001
Aris, B.Aris, B.Alrosa seeks funds to unfreeze god's treasury Russia largest diamond producer was created in 1993 to bolsterEuromoney, Oct. pp. 32-49.RussiaEconomics - history, Company looking to expand operations beyond borders
DS200712-0303
2007
Ariskin, A.Fallon, T.J., Danyushevsky, L.V., Ariskin, A., Green, D.H., Ford, C.E.The application of olivine geothermometry to infer crystallization temperatures of parental liquids; implications for the temperature of MORB magmas.Chemical Geology, Vol. 241, 3-4, pp. 207-233.MantleGeothermometry
DS1988-0018
1988
Ariskin, A.A.Ariskin, A.A., Barmina, G.B., Frenkel, M. Ya.A crystalline mechanism for the tholeitic seriesInternational Geology Review, Vol. 30, No. 4, April pp. 382-389. Database # 17526RussiaTholeite, Magma
DS1992-0040
1992
Ariskin, A.A.Ariskin, A.A., Boudase, K.V., Meshalkin, S.S., Tsekhonya, T.I.Inforex: a dat a base on experimental studies of phase relations in silicatesystemsAmerican Mineralogist, Vol. 77, No. 5, 6, May-June pp. 668-670GlobalComputer, Program -Inforex
DS1993-1124
1993
Ariskin, A.A.Nesterenko, G.V., Ariskin, A.A.Depths of crystallization of basalt magmaGeochemistry International, Vol. 30, No. 8, pp. 77-87RussiaMagma, Clinopyroxenes
DS1996-0041
1996
Ariskin, A.A.Ariskin, A.A., Nikolaev, G.S.An empirical model for the calculation of spinel melt equilibration temperatures in mafic igneous systems at atmospheric pressure #1Contributions to Mineralogy and Petrology, Vol. 123, pp. 282-292.GlobalChromian spinels, Experimental petrology
DS1999-0020
1999
Ariskin, A.A.Ariskin, A.A., Barmina, G.S.An empirical model for the calculation of spinel melt equilibration temperatures in mafic igneous systems ... iron Ti oxides #2Contributions to Mineralogy and Petrology, Vol. 134, No. 2-3, pp. 251-263.MantleLithosphere, atmospheric pressures, Petrology - experimental
DS200412-0046
2004
Ariskin, A.A.Ariskin, A.A., Barmina, G.S.Development of magma crystallization model and its petrological applications.Geochemistry International, Vol. 42, Suppl.1,TechnologyMagmatism - model ( not specific to diamonds)
DS1994-1272
1994
Arit, I.Nelson, E., Forsythe, R., Arit, I.Ridge collision tectonics in terrane developmentJournal of South American Earth Sciences, Vol. 7, No. 3-4. pp. 271-278ChileTectonics
DS1992-1557
1992
Arkanantha..., J.Toft, P.B., Taylor, P.T., Arkanantha..., J., Haggerty, S.E.Interpretation of satellite magnetic-anomalies over the West Africancraton.Tectonophysics, Vol. 212, No. 1-2, Oct. 1, pp. 21-32.West AfricaGeophysics -magnetics, remote sensing, Craton
DS1986-0028
1986
Arkangelskaya, V.V.Arkangelskaya, V.V., Ryabenko, S.V.A new genetic type of rare earth oreInternational Geology Review, Vol. 28, No. 9, Sept. pp. 1086-1095RussiaCarbonatite, rare earth elements (REE).
DS1988-0020
1988
Arkanihamed, J.Arkanihamed, J., Zhao, S.K., Strangway, D.W.Geophysical interpretation of the magnetic anomalies of Chin a derived from Magsat dataGeophysic. Journal, Vol. 95, No. 2, November pp. 347-359ChinaGeophysics, Magnetics
DS1993-0042
1993
Arkanihamed, J.Arkanihamed, J.The bulk magnetization contrast across the ocean continent boundary in the east-coast of North America.Geophysical Journal International, Vol. 115, No. 1, October pp. 152-158.AppalachiaGeophysics -magnetics, Transects
DS1985-0026
1985
Arkani-Hamed, J.Arkani-Hamed, J., Strangway, D.W.An Interpretation of Magnetic Signatures of Aulacogens and Cratons in africa and South America.Tectonophysics, Vol. 113, PP. 257-269.South Africa, South AmericaGeophysics, Gondwana
DS1985-0027
1985
Arkani-Hamed, J.Arkani-Hamed, J., Strangway, D.W., Teskey, D.J., Hood, P.J.Comparison of Magsat and Low Level Aeromagentic Dat a Over The Canadian Shield: Implications for Grm (geopotential Research Mission).Canadian Journal of Earth Sciences, Vol. 22, No. 9, SEPTEMBER PP. 1241-1247.Canada, Ontario, Manitoba, Quebec, SaskatchewanGeotectonics, Geophysics
DS1987-0015
1987
Arkani-Hamed, J.Arkani-Hamed, J., Strangway, D.W.An interpretation of magnetic signatures of subduction zones detected byMAGSAT.Tectonophysics, Vol. 133, pp. 45-55Peru, ChileKurile Trench, Geophysics
DS1988-0019
1988
Arkani-Hamed, J.Arkani-Hamed, J.Differential reduction to the pole of regional magnetic anomaliesGeophysics, Vol. 53, No. 12, December pp. 1592-1600GlobalGeophysics, Magnetics-regional
DS1990-0127
1990
Arkani-Hamed, J.Arkani-Hamed, J., Urquhart, W.E.S.Reduction to the pole of the North American magnetic anomliesGeophysics, Vol. 55, No. 2, February pp. 218-225MidcontinentGeophysics, Magnetics, gravity
DS1990-0128
1990
Arkani-Hamed, J.Arkani-Hamed, J., Urquhart, W.E.S.Reduction to the pole of the North American magnetic anomaliesGeophysics, Vol. 55, No. 2, February pp. 218-225United States, CanadaGeophysics -magnetics, Crust
DS1990-0565
1990
Arkani-Hamed, J.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
DS1990-1512
1990
Arkani-Hamed, J.Verhoef, J., Arkani-Hamed, J.Chemical remanent magnetization of oceanic crustGeophysical Research Letters, Vol. 17, No. 11, October pp. 1945-1948GlobalGeophysics-magnetics, Crust
DS1991-0605
1991
Arkani-Hamed, J.Gregotski, M.E., Jensen, O., Arkani-Hamed, J.Fractal stochastic modeling of aeromagnetic dataGeophysics, Vol. 56, No. 11, November pp. 1706-1715Alberta, OntarioGeophysics, Athabaska Basin, Kirkland Lake
DS1992-0439
1992
Arkani-Hamed, J.Erickson, S.G., Arkani-Hamed, J.Impingement of mantle plumes on the lithosphere: contrast between earth andVenusGeophysical Research Letters, Vol. 19, No. 9, May 4, pp. 885-888MantleLithosphere, Plumes
DS1993-1606
1993
Arkani-Hamed, J.Toft, P.B., Arkani-Hamed, J.Induced magnetization of the oceanic lithosphere and ocean-continent magnetization contrast inferred from Magsat anomaliesJournal of Geophysical Research, Vol. 98, No. B 4, April 10, pp. 6267-6282GlobalGeophysics -magnetics, Iceland Plateau, Magsat Anomalies
DS1993-1607
1993
Arkani-Hamed, J.Toft, P.B., Scowen, A.H., Arkani-Hamed, J., Francis, D.Demagnetization by hydration in deep crustal rocks in the Grenville Province of Quebec, Canada: implications for magnetic anomalies of continental collision zonesGeology, Vol. 21, No. 11, November pp. 999-1002QuebecTectonics, Geophysics -magnetics
DS1995-1137
1995
Arkani-Hamed, J.Macnab, R., Verhoef, J., Roest, W., Arkani-Hamed, J.New database documents the magnetic character of the Arctic and NorthAtlanticEos, Vol. 76, No. 45, Nov. 7, p. 449, 458Arctic, Atlantic OceanGeophysics - database
DS1996-0042
1996
Arkani-Hamed, J.Arkani-Hamed, J., Dyment, J.Magnetic potential and magnetization contrasts of Earth's lithosphereJournal of Geophysical Research, Vol. 101, No. 5, May 10, pp. 1401-26.MantleGeophysics -magnetics
DS1996-0659
1996
Arkani-Hamed, J.Hynes, A., Arkani-Hamed, J., Greiling, R.Subduction of continental margins and the uplift of high pressure metamorphic rocksEarth and Planetary Science Letters, Vol. 140, No. 1-4, May 1, pp. 13-26GlobalTectonics, Subduction -metamorphism
DS2001-1098
2001
Arkani-Hamed, J.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
DS201507-0332
2015
Arkani-Hamed, J.P.Quere, S., Lowman, S., Arkani-Hamed, J.P.Subcontinental sinking slab remnants in a spherical geometry mantle model.Journal of Geophysical Research, Vol. 118, 4, pp. 1760-1777.MantleSubduction
DS1995-0468
1995
Arkanihan, J.Dyment, J., Arkanihan, J.Spreading rate dependent magnetization of the oceanic lithosphere -magnetic anomalies -review... marine.Geophys. Journal of International, Vol. 121, No. 3, June pp. 789-804.OceansGeophysics -magnetics, Lithosphere
DS1900-0641
1908
Arkansas Diamond CompanyArkansas Diamond CompanyA Brief Account of the Discovery and Investigation and the Official Reports of Geologist and Mining Engineer on the Occurrence of Diamonds in Pike County, Arkansas.Litte Rock: Central Publishing Co., 37P.United States, Gulf Coast, Arkansas, PennsylvaniaDiamond Occurrence
DS1989-0034
1989
Arkansaw Geol. Commission Pamphlet handout at 28th. IGC.Arkansaw Geol. Commission Pamphlet handout at 28th. IGC.The geology of Magnet CoveArkansaw Geol. Commission Pamphlet handout at 28th. IGC., 2p. folded brochureArkansasCarbonatite, Phonolite
DS1990-0130
1990
Arksey, R.L.Ash, C.H., Arksey, R.L.Tectonic setting of allochthonous upper mantle ultramafic rocks in the Cache Creek terrane of The north western Canadian CordilleraGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Vancouver 90 Program with Abstracts, Held May 16-18, Vol. 15, p. A4. AbstractBritish ColumbiaUltramafic, Mantle harzburgite
DS1975-0928
1979
Arlen, R.C.Arlen, R.C.The Australian Diamond SearchMelbourne: Potter Partners, 38P.Australia, Western AustraliaDiamond, Prospecting, Investment, Kimberley
DS1991-0031
1991
Armas, C.Armas, C.Exposition by the minister of Energy Mines on Venezuela's new miningpoliciesPreprint Conference on United States and Latin American partnerships in Mining, held, 14pVenezuelaEconomics, Business -Mining policies
DS1960-1066
1969
Armbrust, G.A.Armbrust, G.A.Hydrothermal Alteration of a Breccia Pipe Deposit, Tribag Mine batchawana Bay, Ontario.Economic Geology, Vol. 64, No. 5, PP. 551-563.GlobalBreccia
DS200612-0908
2006
ArmbrusterMenishikov, Y.P., Krivovichev, S.V., Pakhomovsky, Yakovenchuk, Ivanyuk, Mikhailova, Armbruster,SelivanovaChivruaiite, Ca(Ti,Nb)5(Si6O17)2 (OH,O)5.13-14H20, a new mineral from hydrothermal veins of Khibiny and Lovozero alkaline massifs.American Mineralogist, Vol. 91, 5-6, May pp. 922-928.Russia, Kola PeninsulaMineralogy - alkaline
DS1988-0621
1988
Armbruster, J.G.Seeber, L., Armbruster, J.G., Evans, K.Recent historic seismicity in northeastern Ohio: reactivation of Precambrian faults and the role of deep fluid injectionGeological Society of America (GSA) Abstract Volume, Vol. 20, No. 5, March p. 387. abstractGlobalBlank
DS1990-0129
1990
Armbruster, T.Armbruster, T., Rothlisberger, F., Seifert, F.Layer topology, stacking variation, and site distortion in melilite-related compounds in the system CaO-ZnO-GeO2-SiO2American Mineralogist, Vol. 75, No. 7-8, July-August pp. 847-858GlobalMelilite, Experimental petrology
DS1992-0041
1992
Armbruster, T.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
DS1996-0116
1996
Armbruster, T.Beran, A., Libowitzky, E., Armbruster, T.A single crystal infrared spectroscopic and x-ray diffraction study of untwinned San Benito perovskite.Canadian Mineralogist, Vol. 34, pt. 4, August, pp. 803-809.CaliforniaPerovskite, Mineralogy
DS2003-0333
2003
Armbruster, T.Di Pierro, S., Gnos, E., Grobety, B.H., Armbruster, T., Bernasconi, S.M., Ulmer, P.Rock forming moissanite ( natural a-silicon carbide)American Mineralogist, Vol. 88, pp. 1817-21.Aegean SeaGeochemistry
DS2003-0751
2003
Armbruster, T.Krivovichev, S.V., Armbruster, T., Yakovenchuk, V.N., Pakhomovsky, Y.A.Crystal structure of Lamprophyllite - 2M and Lamprophyllite -2O from the LovozeroEuropean Journal of Mineralogy, Vol. 15, 4, pp. 711-18.Russia, Kola PeninsulaAlkaline rocks - mineralogy
DS200412-0450
2003
Armbruster, T.Di Pierro, S., Gnos, E., Grobety, B.H., Armbruster, T., Bernasconi, S.M., Ulmer, P.Rock forming moissanite ( natural a-silicon carbide).American Mineralogist, Vol. 88, pp. 1817-21.TechnologyGeochemistry
DS200412-1056
2003
Armbruster, T.Krivovichev, S.V., Armbruster, T., Yakovenchuk, V.N., Pakhomovsky, Y.A.Crystal structure of Lamprophyllite - 2M and Lamprophyllite -2O from the Lovozero alkaline massif, Kola Peninsula, Russia.European Journal of Mineralogy, Vol. 15, 4, pp. 711-18.Russia, Kola PeninsulaAlkaline rocks, mineralogy
DS1975-0678
1978
Armbrustmacher, T.J.Armbrustmacher, T.J., Brownfield, I.K.Carbonatites in the Wet Mountains Area, Custer and Fremont Counties, colorado.United States Geological Survey (USGS) OPEN FILE., No. 78-177, 5P.United States, Colorado, Rocky MountainsBlank
DS1975-0929
1979
Armbrustmacher, T.J.Armbrustmacher, T.J.Abundance and Distribution of Thorium in the Carbonatite Stock at Iron Hill, Powderhorn District, Gunnison County, Colorado.United States Geological Survey (USGS) OPEN FILE., No. 79-536, 31 P.United States, Colorado, Rocky MountainsBlank
DS1980-0041
1980
Armbrustmacher, T.J.Armbrustmacher, T.J.Major and Minor Element Distribution in Alkaline Rock Complexes of the Wet Mountains Area, Custer and Fremont Counties, colorado.Geological Society of America (GSA), Vol. 12, No. 6, MARCH P. 266.United States, Colorado, Rocky Mountains, Mcclure Mountains, Gem ParkBlank
DS1981-0068
1981
Armbrustmacher, T.J.Armbrustmacher, T.J.Geologic Occurrence and Resource Potential of Thorium in The Wet Mountains Area, Custer and Fremont Counties, Colorado:an Update.Geological Society of America (GSA), Vol. 13, No. 4, P. 190, (abstract.).Colorado, Colorado PlateauKimberlite, Colorado Plateau, Rocky Mountains
DS1982-0071
1982
Armbrustmacher, T.J.Armbrustmacher, T.J.Geochemical Characteristics of Rocks in Alkaline Intrusive Complexes northwestern Montana: Preliminary Results.Geological Society of America (GSA), Vol. 14, No. 6, P. 302, (abstract.).MontanaKimberlite, Carbonatite, Mineral Hill, Idaho, Rainy Creek, Haines
DS1982-0072
1982
Armbrustmacher, T.J.Armbrustmacher, T.J., Hedge, C.E.Genetic implications of minor element and Strontium isotope geochemistry of alkaline rocks complexes...Contributions to Mineralogy and Petrology, Vol. 79, pp. 424-35.ColoradoAlkaline Rocks, Wet Mountains Area
DS1984-0116
1984
Armbrustmacher, T.J.Armbrustmacher, T.J.Alkaline Rock Complexes in the Wet Mountains Area, Custer And Fremont Counties, Colorado.United States Geological Survey (USGS) PROF. PAPER., No. 1269, 33P.United States, Colorado, Rocky MountainsBlank
DS1985-0028
1985
Armbrustmacher, T.J.Armbrustmacher, T.J., Futa, K.Petrology of Alkaline Rocks in the Carbonatite Complex at Iron Hill, Powderhorn District, Gunnison County, Colorado - New Geochemical and isotopic Data.Geological Society of America (GSA), Vol. 17, No. 3, FEBRUARY P. 149. (abstract.).United States, Colorado, Rocky MountainsAnalyses, Isotope
DS1985-0207
1985
Armbrustmacher, T.J.Futa, K., Armbrustmacher, T.J.Combined Rubidium-strontium and Samarium-neodymium (sm-nd) Systems Study on Three Alkaline Intrusive Complexes in Northwestern Montana.Geological Society of America (GSA), Vol. 17, No. 3, P. 159. (abstract.).United States, Montana, Rocky MountainsIsotope, Geochronology, Rainy Creek, Haines Point, Skalkaho
DS1989-0035
1989
Armbrustmacher, T.J.Armbrustmacher, T.J.Geology and resources of thorium and associated elements in the Wet Mountains area, Fremont and Custer counties, ColoradoUnited States Geological Survey (USGS) Prof. Paper, No. P 1049-F, F1-F34. $ 2.50ColoradoCarbonatite dikes
DS1991-0715
1991
Armbrustmacher, T.J.Hills, F.A., Scott, R.W., Armbrustmacher, T.J., Berendsen, P.Map showing distribution of alkaline igneous rocks and associated carbonatites and peridotites in the northern mid-continent, United States (US)United States Geological Survey (USGS) Map, No. MF-1835-F, 15p. 1 map 1: 1, 000, 000 $ 1.50MidcontinentCarbonatite, Map -Alkaline intrusives
DS1991-0716
1991
Armbrustmacher, T.J.Hills, F.A., Scott, R.W., Armbrustmacher, T.J., Berendsen, P.Map showing the distribution of alkaline igneous rocks and associated carbonatites and peridotites in the northern mid-continent, United States (US)United States Geological Survey (USGS) Map, No. MF 1835-F, 1: 1, 000, 000MidcontinentMap, Carbonatite
DS1994-0063
1994
Armbrustmacher, T.J.Armbrustmacher, T.J.Fenitization of host rocks in the contact aureole of the carbonatite stockat Iron Hill, Gunnison County, Colorado.Geological Society of America Abstracts, Vol. 26, No. 6, April p. 2. Abstract.ColoradoCarbonatite, Iron Hill
DS1994-1223
1994
Armbrustmacher, T.J.Modreski, P.J., Armbrustmacher, T.J., Ryka, W.Mineralogy of magmatic and metasomatic rocks of the Elk Massif, northeastPoland.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.GlobalMineralogy, Elk Massif
DS2002-0058
2002
Armienti, P.Armienti, P., Tarquini, S.Power law olivine crystal size distributions in lithospheric mantle xenolithsLithos, Vol. 65, 3-4, Dec. pp. 273-85.MantleCrystallography, xenoliths
DS2002-0059
2002
Armienti, P.Armienti, P., Tarquini, S.Power law olivine crystal size distribution in lithospheric mantle xenolithsLithos, Vol. 65, 3-4, pp. 273-85.MantleXenoliths - olivine crystallography, morphology
DS201412-0675
2014
Armienti, P.Perlinelli, C., Bosi, F., Andreozzi, G.B., Conte, A.M., Armienti, P.Geothermometric study of Cr-spinels of peridotite mantle xenoliths from northern Victoria Land ( Antarctica).American Mineralogist, Vol. 99, pp. 839-846.AntarcticaSpinel
DS201705-0854
2017
Armistead, S.Merdith, A.S., Collins, A.S., Williams, S.E., Pisarevsky, S., Foden, J.F., Archibald, D., Blades, M.L., Alessio, B.L., Armistead, S., Plavsa, D., Clark, C., Muller, R.D.A full plate global reconstruction of the Neoproterozoic.Gondwana Research, in press available 155p.Gondwana, RodiniaGeodynamics

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

Abstract: Neoproterozoic tectonic geography was dominated by the formation of the supercontinent Rodinia, its break-up and the subsequent amalgamation of Gondwana. The Neoproterozoic was a tumultuous time of Earth history, with large climatic variations, the emergence of complex life and a series of continent-building orogenies of a scale not repeated until the Cenozoic. Here we synthesise available geological and palaeomagnetic data and build the first full-plate, topological model of the Neoproterozoic that maps the evolution of the tectonic plate configurations during this time. Topological models trace evolving plate boundaries and facilitate the evaluation of “plate tectonic rules” such as subduction zone migration through time when building plate models. There is a rich history of subduction zone proxies preserved in the Neoproterozoic geological record, providing good evidence for the existence of continent-margin and intra-oceanic subduction zones through time. These are preserved either as volcanic arc protoliths accreted in continent-continent, or continent-arc collisions, or as the detritus of these volcanic arcs preserved in successor basins. Despite this, we find that the model presented here still predicts less subduction (ca. 90%) than on the modern earth, suggesting that we have produced a conservative model and are likely underestimating the amount of subduction, either due to a simplification of tectonically complex areas, or because of the absence of preservation in the geological record (e.g. ocean-ocean convergence). Furthermore, the reconstruction of plate boundary geometries provides constraints for global-scale earth system parameters, such as the role of volcanism or ridge production on the planet's icehouse climatic excursion during the Cryogenian. Besides modelling plate boundaries, our model presents some notable departures from previous Rodinia models. We omit India and South China from Rodinia completely, due to long-lived subduction preserved on margins of India and conflicting palaeomagnetic data for the Cryogenian, such that these two cratons act as ‘lonely wanderers’ for much of the Neoproterozoic. We also introduce a Tonian-Cryogenian aged rotation of the Congo-São Francisco Craton relative to Rodinia to better fit palaeomagnetic data and account for thick passive margin sediments along its southern margin during the Tonian. The GPlates files of the model are released to the public and it is our expectation that this model can act as a foundation for future model refinements, the testing of alternative models, as well as providing constraints for both geodynamic and palaeoclimate models.
DS201709-1954
2017
Armistead, S.E.Armistead, S.E., Collins, A.S., Payne, J.L., Foden, J.D., De Waele, B., Shaji, E., Santosh, M.A re-evaluation of the Kumta Suture in western peninsular India and its extension into Madagascar,Journal of Asian Earth Sciences, in press available, 47p.India, Africa, Madagascartectonis

Abstract: It has long been recognised that Madagascar was contiguous with India until the Late Cretaceous. However, the timing and nature of the amalgamation of these two regions remain highly contentious as is the location of Madagascar against India in Gondwana. Here we address these issues with new U-Pb and Lu-Hf zircon data from five metasedimentary samples from the Karwar Block of India and new Lu-Hf data from eight previously dated igneous rocks from central Madagascar and the Antongil-Masora domains of eastern Madagascar. New U-Pb data from Karwar-region detrital zircon grains yield two dominant age peaks at c. 3100 Ma and c. 2500 Ma. The c. 3100 Ma population has relatively juvenile eHf(t) values that trend toward an evolved signature at c. 2500 Ma. The c. 2500 Ma population shows a wide range of eHf(t) values reflecting mixing of an evolved source with a juvenile source at that time. These data, and the new Lu-Hf data from Madagascar, are compared with our new compilation of over 7000 U-Pb and 1000 Lu-Hf analyses from Madagascar and India. We have used multidimensional scaling to assess similarities in these data in a statistically robust way. We propose that the Karwar Block of western peninsular India is an extension of the western Dharwar Craton and not part of the Antananarivo Domain of Madagascar as has been suggested in some models. Based on eHf(t) signatures we also suggest that India (and the Antongil-Masora domains of Madagascar) were palaeogeographically isolated from central Madagascar (the Antananarivo Domain) during the Palaeoproterozoic. This supports a model where central Madagascar and India amalgamated during the Neoproterozoic along the Betsimisaraka Suture.
DS201904-0715
2019
Armistead, S.E.Armistead, S.E., Collins, A.S., Redaa, A., Gilbert, S., Jepson, G., Gillespie, J., Blades, M.L., Foden, J.D., Razakamana, T.Structural evolution and medium temperature thermochronology of central Madagascar: implications for Gondwana amalgamation.Journal of the Geological Society of London, in press available 25p.Africa, Madagascarthermochronology

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

Abstract: Madagascar occupied an important place in the amalgamation of Gondwana and preserves a record of several Neoproterozoic events that are linked to orogenesis of the East African Orogen. In this study, we integrate remote sensing, field data and thermochronology to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic foliation (S1), followed by south- to SW-directed, tight to isoclinal, recumbent folding (D2). These are overprinted by north-trending upright folds that formed during an approximately east-west shortening event (D3). Together these produced type 1 and type 2 fold interference patterns throughout the Itremo and Ikalamavony domains. We show that the Itremo and Ikalamavony domains were deformed together in the same orogenic system, which we interpret as the c. 630 Ma collision of Azania with Africa along the Vohibory Suture in southwestern Madagascar. In eastern Madagascar, deformation is syn- to post-550 Ma, and probably formed in response to final closure of the Mozambique Ocean along the Betsimisaraka Suture that amalgamated Madagascar with the Dharwar Craton of India. Apatite U-Pb and novel laser ablation triple quadrupole inductively coupled plasma mass spectrometry (LA-QQQ-ICP-MS) muscovite and biotite Rb-Sr thermochronology indicates that much of central Madagascar cooled through c. 500°C at c. 500 Ma.
DS201606-1078
2016
Armit, R.J.Betts, P.G., Armit, R.J., Stewart, J., Aitken, A.R.A., Aileres, L., Donchak, P., Hutton, L., Withnall, I., Giles, D.Australia and Nuna.Geological Society of London Special Publication Supercontinent Cycles through Earth History., Vol. 424, pp. 47-81.AustraliaSupercontinents

Abstract: The Australian continent records c. 1860-1800 Ma orogenesis associated with rapid accretion of several ribbon micro-continents along the southern and eastern margins of the proto-North Australian Craton during Nuna assembly. The boundaries of these accreted micro-continents are imaged in crustal-scale seismic reflection data, and regional gravity and aeromagnetic datasets. Continental growth (c. 1860-1850 Ma) along the southern margin of the proto-North Australian Craton is recorded by the accretion of a micro-continent that included the Aileron Terrane (northern Arunta Inlier) and the Gawler Craton. Eastward growth of the North Australian Craton occurred during the accretion of the Numil Terrane and the Abingdon Seismic Province, which forms part of a broader zone of collision between the northwestern margins of Laurentia and the proto-North Australian Craton. The Tickalara Arc initially accreted with the Kimberley Craton at c. 1850 Ma and together these collided with the proto-North Australian Craton at c. 1820 Ma. Collision between the West Australian Craton and the proto-North Australian Craton at c. 1790-1760 Ma terminated the rapid growth of the Australian continent.
DS1994-1083
1994
Armitage, A.E.MacRae, N.D., Armitage, A.E., Miller, A.R.Diamond bearing potential of alkaline dykes in the Gibson Lake area, District of Keewatin, northwest Territories.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.Northwest TerritoriesAlkaline dykes, Gibson Lake area
DS1995-0891
1995
Armitage, A.E.Jones, A.L., Miller, A.R., Armitage, A.E., MacRae, N.D.Lamprophyre dikes of the Christopher Island Formation, Thirty Mile Lake, District of Keewatin.Geological Survey of Canada, Paper 1995-C, pp. 187-194.Northwest TerritoriesLamprophyre dykes
DS1995-1140
1995
Armitage, A.E.MacRae, N.D., Armitage, A.E., Jones, A.L.A Diamondiferous lamprophyre dike, Gibson Lake area, NorthwestTerritories.International Geology Review, Vol. 37, pp. 212-229.Northwest TerritoriesLamprophyre, diamond, Deposit -Akluilak dike
DS1996-0870
1996
Armitage, A.E.MacRae, N.D., Armitage, A.E., Miller, A.R., Roddick, J.C.The Diamondiferous Akluilak lamprophyre dyke, Gibson Lake area, northwest TerritoriesGeological Survey of Canada, LeCheminant ed, OF 3228, pp. 101-107.Northwest TerritoriesLamprophyre, Akluilak dyke
DS1998-1008
1998
Armitage, A.E.Miller, A.R., Seller, M.H., Armitage, A.E., DavisLate Triassic kimberlitic magmatism, western Churchill structural Canada.7th International Kimberlite Conference Abstract, pp. 591-3.Northwest TerritoriesKimberlite magmatism, dikes, Deposit - Rankin Inlet area
DS1992-0042
1992
Armitage, D.L.Armitage, D.L.Using areal criteria to perform trend analysisGeobyte, Vol. 7, No. 4, August/September pp. 54-57GlobalComputer, Program - filter residual
DS201012-0011
2010
Armitage, J.J.Armitage, J.J., Allen, P.A.Cratonic basins and the long term subsidence history of continental interiors.Journal of the Geological Society, Vol. 167, 1, pp. 61-70.MantleConvection
DS200912-0011
2009
Armitage, M.H.Armitage, M.H., Snelling, A.A.Radiohalos and diamonds Are diamond really for ever? Answers in genesis.Proceedsings of the Sixth International Conference on Creationism, Sept. 9, 20p.MantleJust for interest!
DS201906-1267
2019
Armitage, P.E.B.Armitage, P.E.B.The Songwe Hill rare earths project, Malawi - geological observations on the recently announced mineral resource upgrade.3rd International Critical Metals Meeting held Edinburgh, 1p. Abstract p. 37.Africa, Malawideposit - Songwe Hill

Abstract: PDF link to the presentation.
DS201012-0481
2010
Armour-Brown, A.McCreath, J.A., Finch, A.A., Donaldson, C.H., Armour-Brown, A.The petrology and petrogenesis of one of the world's biggest Ta deposits - the Motzfeldt Centre, South Greenland.International Workshop Geology of Rare Metals, held Nov9-10, Victoria BC, Open file 2010-10, extended abstract pp.43.Europe, GreenlandAlkalic
DS1997-0573
1997
ArmstrongKatsube, T.J., Connell, S., McClenaghan, M.B., ArmstrongPetrophysical characteristics of limestone xenoliths in kimberlites from Kirkland Lake, Ontario.Geological Survey of Canada (GSC) Paper, No.1997-E, pp. 45-57.Ontario, Kirkland LakePetrology
DS1999-0740
1999
ArmstrongTompkins, L.A., Meyer, Han, Hu, Armstrong, TaylorPetrology and chemistry of kimberlites from Shandong and Liaoning Provinces7th International Kimberlite Conference Nixon, Vol. 2, pp. 872-87.China, Shandong, FuxianMineral chemistry, trace, multi, analyses, thermometry, Deposit - Mengyin, Fuxian
DS2001-0726
2001
ArmstrongManhica, A.S.T.D., Grantham, Armstrong, Guise, KrugerPolyphase deformation and metamorphism at the Kalahari Craton - Mozambique Belt boundary.Geological Society of London, Special Publication, Special Paper 184, pp. 303-22.South Africa, MozambiqueMetamorphism, Craton
DS200912-0387
2009
ArmstrongKlein, E.L., Luzardo, R., Moura, Lobato, Brito, ArmstrongGeochronology, Nd isotopes and reconnaissance geochemistry of volcanic and metavolcanic rocks of Sao Luis Craton, northern Brazil: tectonics and crustalJournal of South American Earth Sciences, Vol. 27, 2-3, pp. 129-145.South America, BrazilGeochronology
DS200612-1324
2005
Armstrong, A.R.Smith, A.C., Virgl, J.A., Panayi, D., Armstrong, A.R.Effects of a diamond mine on Tundra breeding birds.Arctic ( Arctic Institute of North America), Vol. 38, 3, pp. 295-304.Canada, Northwest TerritoriesEnvironemental
DS1996-0921
1996
Armstrong, D.K.McCracken, A.D., Armstrong, D.K., McGregor, D.C.Fossils as indicators of thermal alteration associated with kimberlitesGeological Survey of Canada, LeCheminant ed, OF 3228, pp. 143-145.Quebec, OntarioPaleontology, Thermal histories
DS2000-0644
2000
Armstrong, D.K.McCracken, A.D., Armstrong, D.K., Bolton, T.E.Conodonts and corals in kimberlite xenoliths confirm a Devonian seaway in central Ontario and Quebec.Canadian Journal of Earth Sciences, Vol. 37, No.12, Dec. pp. 1651-63.Ontario, QuebecXenoliths, paleontology, Kirkland Lake area, Lake Timiskaming
DS1989-1651
1989
Armstrong, et al.Woodsworth, G.J., Anderson, R.G., Armstrong, et al.A database of plutonic regimes in the Canadian CordilleraGeological Survey of Canada (GSC) Open file, No. 2369, 1:1, 000, 000Alberta, CordilleraDiatremes
DS200712-1173
2007
Armstrong, G.Wolmarans, P., Armstrong, G.New developments in diamond recovery and security procedures - preserving the dollars. Excellent pictoral- x-ray and optical sorting, material handlingDiamonds in Kimberley Symposium & Trade Show, Bristow and De Wit held August 23-24, Kimberley, South Africa, GSSA Diamond Workshop CD slides 1-94.Africa, South AfricaOverview - mineral processing, recovery
DS2001-0042
2001
Armstrong, G.D.Armstrong, G.D., Watts, A.B.Spatial variations in southern Appalachians, eastern United StatesJournal of Geophysical Research, Vol. 106, No. 10, pp.22,009-26.ArkansasGeophysics - seismics
DS1999-0021
1999
Armstrong, H.A.Armstrong, H.A., Owen, A.W., Floyd, D.J.Rare earth geochemistry of Arenig cherts from the Ballantrae ophiolite and Leadhills imbricate zone....Journal of Geological Society of London, Vol. 156, No. 3, May pp. 549-60.ScotlandCaledonian Orogeny, Geochronology
DS1999-0022
1999
Armstrong, J.Armstrong, J.KIDD ( Kimberlite indicator and diamond database): compilation of till sample locations and picking resultnorthwest Territories Geology Division, DIAND., No. 1999-03.Northwest TerritoriesGeochemistry - till samples, KIDD database
DS1999-0023
1999
Armstrong, J.Armstrong, J.KIDD ( Kimberlite indicator and diamond database): compliation of till sample locations and picking resultnorthwest Territories Geology Division, DIAND., No. 1999-03.Northwest TerritoriesGeochemistry - till samples, KIDD database
DS2000-0506
2000
Armstrong, J.Kjarsgaard, B., Wilkinson, L., Stasiuk, V., Armstrong, J.Understanding the Diamondiferous Lac de Gras kimberlite field28th. Yellowknife Geoscience Forum, p. 44-5.abstractNorthwest TerritoriesKimberlite - volcanism., GIS project
DS2001-0043
2001
Armstrong, J.Armstrong, J.Alkaline magmatic events - Leith Lake carbonatite and Yellowknife lamprophyres: evidence for Archean mantleSlave-Kaapvaal Workshop, Sept. Ottawa, 4p. abstractNorthwest TerritoriesMetasomatism, southern Slave Craton, Leith Lake, Yellowknife lamprophyres
DS2002-0861
2002
Armstrong, J.Kjarsgaard, B.A., Wilkinson, L., Armstrong, J.Geology Lac de Gras kimberlite field, central Slave Province, Northwest Territories, Nunuvut NTS 76 D.C.E,F.Geological Survey of Canada Open File, No. 3228, 1 colour map 1:250,000 $ 15.00Northwest Territories, NunavutMap - geology, Deposit - Lac de Gras
DS2003-0347
2003
Armstrong, J.Dowall, D.P., Pearson, D.G., Nowell, G.M., Kjarsgaard, B.A., Armstrong, J.Comparative geochemistry of kimberlites from the Lac de Gras field, NWT - an8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractNorthwest TerritoriesKimberlite petrogenesis, Geochronology, database 98
DS200412-0474
2003
Armstrong, J.Dowall, D.P., Pearson, D.G., Nowell, G.M., Kjarsgaard, B.A., Armstrong, J., Hortswood, M.S.A.Comparative geochemistry of kimberlites from the Lac de Gras field, NWT - an integrated isotopic and elemental study.8 IKC Program, Session 7, AbstractCanada, Northwest TerritoriesKimberlite petrogenesis, Database 98
DS200612-0036
2005
Armstrong, J.Armstrong, J.Stornoway Diamond Corp. recent kimberlite discoveries on Wales Island: a new kimberlite field in central Nunavut.32ndYellowknife Geoscience Forum, p. 2 abstractCanada, NunavutUpdate - Stornoway
DS200812-0493
2008
Armstrong, J.Hunt, L., Stachel, T., Simonetti, T., Armstrong, J., McCandless, T.E.Microxenoliths from the Renard kimberlites, Quebec.Northwest Territories Geoscience Office, p. 35-36. abstractCanada, QuebecBrief overview - Stornoway
DS200912-0321
2009
Armstrong, J.Hunt, L., Stachel, T., Armstrong, J.Trace element systematics of microxenoliths and xenocrysts from the Renard kimberlites, Quebec.37th. Annual Yellowknife Geoscience Forum, Abstracts p. 26.Canada, QuebecGeothermometry
DS200912-0339
2009
Armstrong, J.Johnson, C., Stachel, T., Muehlenbachs, K., Armstrong, J.The micro-/macro diamond relationship: a preliminary case study on diamonds from Artemisia kimberlite ( northern Slave Craton), Canada.37th. Annual Yellowknife Geoscience Forum, Abstracts p. 74-75.Canada, Nunavut, Coronation Gulfmicrodiamonds
DS201012-0298
2010
Armstrong, J.Hunt, L., Stachel, T., Armstrong, J.Evolution of SCLM beneath the Renard kimberlites, SE Superior Craton: an integrated study of diamonds, xenoliths and xenocrysts.Goldschmidt 2010 abstracts, abstractCanada, QuebecDeposit - Renard
DS201012-0328
2010
Armstrong, J.Johnson, C.N., Stern, R., Stachel, T., Muehlenbachs, K., Armstrong, J.The micro/macro diamond relationship: a case study from the Artemisia kimberlite northern Slave Craton ( Nunavut, Canada).38th. Geoscience Forum Northwest Territories, Abstract p. 52.Canada, NunavutDeposit - Artemisia
DS201012-0571
2010
Armstrong, J.Peats, J., Stachel, T., Stern, R., Muehlenbachs, K., Armstrong, J.Aviat diamonds as a window into the deep lithospheric mantle beneath the northern Churchill province.38th. Geoscience Forum Northwest Territories, Abstract pp.118-119.Canada, Northwest Territories, Melville PeninsulaGeochronology - nitrogen, CI
DS201212-0202
2012
Armstrong, J.Fitzgerald, C.E., Lepine, I., Armstrong, J.Geology of the kimberlite pipes of the Renard cluster, Quebec, Canada.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, QuebecDeposit - Renard
DS201212-0320
2012
Armstrong, J.Hunt, L., Stachel, T., Grutter, H., Armstrong, J., McCandless, T.E., Simonetti, A., Tappe, S.Small mantle fragments from the Renard kimberlites, Quebec: powerful recorders of mantle lithosphere formation and modification beneath the eastern Superior Craton.Journal of Petrology, Vol. 53, 8, pp. 1597-1635.Canada, QuebecDeposit - Renard
DS201212-0321
2012
Armstrong, J.Hunt, L., Stachel, T., McCandless, T.E., Armstrong, J., Muelenbachs, K.Diamonds and their mineral inclusions from the Renard kimberlites in Quebec.Lithos, in press availableCanada, QuebecDeposit - Renard
DS201212-0547
2012
Armstrong, J.Peats, J., Stachel, T., Ster, R.A., Muehlenbachs, K., Armstrong, J.Aviat diamonds: a window into the deep lithospheric mantle beneath the Northern Churchill Province, Melville Peninsula, Canada.Canadian Mineralogist, Vol. 50, 3, June pp. 611-624.Canada, Nunavut, Melville PeninsulaDeposit - Aviat
DS201412-0282
2014
Armstrong, J.George, T., Armstrong, J.Karowe mine - a diamond development success story.Vancouver Kimberlite Cluster, Jan. 24, 1p. AbstractAfrica, BotswanaHistory - Karowe
DS201602-0188
2016
Armstrong, J.Armstrong, J.Karowe diamond mine: a world class source of exceptional diamonds.PDAC 2016, 1p. AbstractAfrica, BotswanaDeposit - Karowe
DS201605-0912
2016
Armstrong, J.Van Niekerk, L.M., Oliver, A., Armstrong, J., Sikwa, N.A.Pioneering large diamond recovery at Karowe diamond mineDiamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 15-26.Africa, BotswanaDeposit - Karowe
DS201708-1593
2017
Armstrong, J.Armstrong, J.Karowe diamond mine: a world class source of exceptional diamonds.11th. International Kimberlite Conference, OralAfrica, Botswanadeposit - Karowe

Abstract: The Karowe mine, owned and operated by Lucara Diamond Corporation, located in the Republic of Botswana, achieved commercial diamond production in July 2012. The AK06 kimberlite discovered in 1969 is the ore source at Karowe. The AK06 kimberlite within the Orapa Kimberlite Field is a roughly north-south elongate kimberlite body with a near surface expression of approximately 3.3 ha and a maximum area of approximately 7 ha at approximately 120 m below surface. The body comprises three geologically distinct, coalescing pipes that taper with depth. These pipes are referred to as the North Lobe, Centre Lobe, and South Lobe. The AK6 kimberlite is an opaque-mineral-rich monticellite kimberlite, texturally classified primarily as fragmental volcaniclastic kimberlite with lesser macrocrystic hypabyssal facies kimberlite of the Group 1 variety. The nature of the kimberlite differs between each lobe with distinctions apparent in the textural characteristics. The South Lobe is considered to be distinctly different from the North and Centre Lobes that are similar to each other in terms of their geological characteristics. The North and Centre Lobes exhibit internal textural complexity whereas the bulk of the South Lobe is more massive and internally homogeneous. The South Lobe forms the majority of the resource and displays the coarsest diamond size distribution of the three lobes. In three years of production, Karowe has established a continuing production of high value diamonds including coloured diamonds. In March 2013 a 239 ct gem quality diamond was recovered which was the first in a continuing population of large high value Type IIa diamonds recovered from the Centre Lobe, and more importantly the South Lobe, of the Karowe mine. Large diamonds, 50 ct in size, are spatially distributed horizontally and vertically within the South Lobe. Since commissioning to mid-December 2015, approximately 1.5 Mct have been produced and specials (diamonds greater than 10.8 ct in weight) represent circa 4.6% by weight of all diamond production. Life of Mine average stone size for the specials is 29.6 ct/stone. In 2015, a plant optimization project was completed to modify the process plant to treat harder kimberlite at depth and improve the recovery of exceptional diamonds via bulk sorters for primary run of mine large diamond recovery. In November 2015, the Karowe mine recovered an 813 ct stone and the world’s second largest gem quality diamond in over 100 years weighing 1,111 ct
DS201709-2069
2016
Armstrong, J.Van Niekirk, L.M., Olivier, A., Armstrong, J., Sikwa, N.A.Pioneering large diamond recovery at Karowe diamond mine.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 709-714.Africa, Botswanadeposit - Karowe

Abstract: Historically, the recovery of large diamonds in conventional treatment plant flow sheets has been associated with dense media separation (DMS). This is attributed mainly to DMS's highly efficient and proven track record in the concentration and separation of ores with variable solids densities. In most instances, DMS has been utilized as a pre-concentration step ahead of any recovery plant, due to its ability and versatility in reducing feed within a specific size range to manageable volumes for downstream X-ray processing and subsequent diamond recovery. The benefit of using carbon-signature-based detection equipment for retrieving large stones upfront in the flow sheet not only equates to earlier recovery of diamonds from the system, but also lessens the exposure of diamond-bearing ore to additional materials handling, pumping, and/or crushing, which has been known to damage or even break diamonds and decrease revenue.
DS201804-0670
2018
Armstrong, J.Armstrong, J.Mining and extracting the world's largest diamonds. Karowe4th International Diamond School: Diamonds, Geology, Gemology and Exploration Bressanone Italy Jan. 29-Feb. 2nd., pp. 9-10. abstractAfrica, Botswanadeposit - Karowe
DS201808-1769
2018
Armstrong, J.Motsamai, T., Harris, J.W., Stachel, T., Pearson, D.G., Armstrong, J.Mineral inclusions in diamonds from Karowe mine, Botswana: super-deep sources for super-sized diamonds?Mineralogy and Petrology, doi.org/10.1007/s00710-018-0604-9 12p.Africa, Botswanadeposit - Karowe

Abstract: Mineral inclusions in diamonds play a critical role in constraining the relationship between diamonds and mantle lithologies. Here we report the first major and trace element study of mineral inclusions in diamonds from the Karowe Mine in north-east Botswana, along the western edge of the Zimbabwe Craton. From a total of 107 diamonds, 134 silicate, 15 oxide, and 22 sulphide inclusions were recovered. The results reveal that 53% of Karowe inclusion-bearing diamonds derived from eclogitic sources, 44% are peridotitic, 2% have a sublithospheric origin, and 1% are websteritic. The dominant eclogitic diamond substrates sampled at Karowe are compositionally heterogeneous, as reflected in wide ranges in the CaO contents (4-16 wt%) of garnets and the Mg# (69-92) and jadeite contents (14-48 mol%) of clinopyroxenes. Calculated bulk rock REEN patterns indicate that both shallow and deep levels of the subducted slab(s) were sampled, including cumulate-like protoliths. Peridotitic garnet compositions largely derive from harzburgite/dunite substrates (~90%), with almost half the garnets having CaO contents <1.8 wt%, consistent with pyroxene-free (dunitic) sources. The highly depleted character of the peridotitic diamond substrates is further documented by the high mean and median Mg# (93.1) of olivine inclusions. One low-Ca garnet records a very high Cr2O3 content (14.7 wt%), implying that highly depleted cratonic lithosphere at the time of diamond formation extended to at least 220 km depth. Inclusion geothermobarometry indicates that the formation of peridotitic diamonds occurred along a 39-40 mW/m2 model geotherm. A sublithospheric inclusion suite is established by three eclogitic garnets containing a majorite component, a feature so far unique within the Orapa cluster. These low- and high-Ca majoritic garnets follow pyroxenitic and eclogitic trends of majoritic substitution, respectively. The origin of the majorite-bearing diamonds is estimated to be between 330 to 420 km depth, straddling the asthenosphere-transition zone boundary. This new observation of superdeep mineral inclusions in Karowe diamonds is consistent with a sublithospheric origin for the exceptionally large diamonds from this mine.
DS200412-1509
2003
Armstrong, J.A.Pearson, D.G., Nowell, G.M., Dowall, D.P., Kjarsgaard, B.A., Kopylova, M.G., Armstrong, J.A.The relative roles of lithosphere and convecting mantle in kimberlites from the Slave Province NWT: constraints from Re Os isoto8 IKC Program, Session 7, AbstractCanada, Northwest TerritoriesKimberlite petrogenesis Geochronology
DS1900-0531
1907
Armstrong, J.A.H.Armstrong, J.A.H.Sedimentary Deposits in NatalSouth African Association ADVANCE. SCIENCE (NATAL), PP. 71-75.Africa, South AfricaGeology
DS1999-0252
1999
Armstrong, J.M.Gillin, R.P., Armstrong, J.M.Financing the mining industry: techniques, trends and outlookNorth Atlantic Mineral Symposium, Sept., abstracts pp. 180-82.GlobalEconomics - techniques, brief overview, Financing - not specific to diamonds
DS1998-0042
1998
Armstrong, J.P.Armstrong, J.P.An overview of exploration activities in the Northwest Territories. ( 1/2pg. on diamonds).Calgary Mining Forum, Apr. 8-9, p. 33-5. abstractNorthwest TerritoriesCurrent activities, Deposit - Ekati, Diavik
DS1998-0043
1998
Armstrong, J.P.Armstrong, J.P.northwest Territories kimberlite occurrence database. Occurrence listing - one line chart lat longs ref. and anomaly comment.northwest Territories Geology Division, EGS 1998-13, 4p.Northwest TerritoriesDatabase - comment, Geophysics
DS1998-0044
1998
Armstrong, J.P.Armstrong, J.P.northwest Territories kimberlite occurrencesnorthwest Territories Geology Division, DIAND., EGS 1998-13, map 1:250, 000Northwest Territories, NunavutMap - occurrences
DS1999-0024
1999
Armstrong, J.P.Armstrong, J.P.An overview of activities in the Northwest and Nunavut Territories8th. Calgary Mining forum, 2p. abstractNorthwest Territories, NunavutOverview, Exploration activities - brief
DS2000-0028
2000
Armstrong, J.P.Armstrong, J.P., Lee, C.A.A compilation of publically available till sample locations and Kimberlite indicator mineral pick resultsDiand, Economic Series, 2000-3, 1 disc.Northwest TerritoriesMineral chemistry
DS2000-0029
2000
Armstrong, J.P.Armstrong, J.P., Lee, C.A.KIDD: a compilation of publically available till sample locations and picking results Slave Craton and environsnorthwest Territories Geology Division, DIAND., Open file 2000-003, $ 5.00Northwest Territories, NunavutGeochemistry - till samples
DS2000-0030
2000
Armstrong, J.P.Armstrong, J.P., Strand, P.D., Duke, N.A.Archean lamprophyre diking, Yellowknife Greenstone Belt, between mantle sourced magmatic events, ....28th. Yellowknife Geoscience Forum, p. 7-8.abstractNorthwest TerritoriesLamprophyre - dykes
DS2001-0044
2001
Armstrong, J.P.Armstrong, J.P.A comparison of zincian spinels from selected Diamondiferous and non-Diamondiferous Archean dykes...29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p.1.Northwest TerritoriesLamprophyre dikes, Related rocks - alkaline
DS2001-0045
2001
Armstrong, J.P.Armstrong, J.P., Chatman, J.A preliminary digital compilation of kimberlite indicator mineral chemistry (KMC) extracted assessmentnorthwest Territories and DIAND Open File, EGS 2001-02, CD.Northwest Territories, NunavutGeochemistry, Slave Craton region
DS2001-0046
2001
Armstrong, J.P.Armstrong, J.P., Kenny, G.Slave magnetics compilation, (SMAC) a digital image compilation of publically available total field Magazine29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p.3-4.Northwest Territories, NunavutGeophysics - total field magnetic, GIS - database
DS2001-0047
2001
Armstrong, J.P.Armstrong, J.P., Preston, Y.Kimberlite anomaly diamond drill hole compilation - a GIS compatible compilation locations and logs ...29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p.2-3.Northwest Territories, NunavutKimberlite anomalies - drill logs, GIS - database
DS2002-0060
2002
Armstrong, J.P.Armstrong, J.P.A lineament study of the Slave Craton and environs, the tale of a cracked craton: a work in progress.30th. Yellowknife Geoscience Forum, Abstracts Of Talks And Posters, Nov. 20-22, p. 1. abstractNorthwest TerritoriesDyke swarms - classification
DS2002-0061
2002
Armstrong, J.P.Armstrong, J.P.Diamond industry continues to build momentumProspectors and Developers Association of Canada (PDAC) Exploration and Development Highlights, pp. 31-2.Northwest TerritoriesNews item - brief review
DS2002-0062
2002
Armstrong, J.P.Armstrong, J.P.Diamond exploration dat a North Slave Craton, NUNunavut Open File, No. 2002-01, CD.Northwest Territories, NunavutGeochemistry - exploration, analyses, data
DS2002-0063
2002
Armstrong, J.P.Armstrong, J.P.A comparison of zincian spinels from selected Diamondiferous and nonDiamondiferous Archean lamprophyre dikes.University of Western Ontario, SEG Student Chapter, March 8, pp. 19-20. abstractOntario, wawa, Northwest Territories, YellowknifePetrography - brief descriptions
DS2003-0027
2003
Armstrong, J.P.Armstrong, J.P.Diamond discovery in the Slave Craton: compilations of exploration dat a as tools for8ikc, Www.venuewest.com/8ikc/program.htm, Session 5, POSTER abstractNorthwest TerritoriesTarget area selection
DS2003-0028
2003
Armstrong, J.P.Armstrong, J.P.Regional distribution of kimberlite indicator minerals, Slave Craton, Northwest31st Yellowknife Geoscience Forum, p. 1. (abst.)Northwest Territories, NunavutGeochemistry - KIM
DS2003-0029
2003
Armstrong, J.P.Armstrong, J.P., Barnett, R.L.The association of ZN chromite with Diamondiferous lamprophyres and diamonds:8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractNorthwest Territories, Yellowknife, Ontario, WawaBlank
DS2003-0030
2003
Armstrong, J.P.Armstrong, J.P., Wilson, M., Barnett, R.L., Nowicki, T., Kjarsgaard, B.A.Paragenesis of primary magmatic Sr Ba Mg Ca carbonates from ultra fresh hypabyssal8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractNorthwest TerritoriesKimberlite petrogenesis, Deposit - Ekati block
DS2003-0031
2003
Armstrong, J.P.Armstrong, J.P., Wilson, M., Barnett, R.L., Nowicki, T., Kjarsgaard, B.A.Mineralogy of calcite and calcite dolomite solid solution bearing hypabyssal kimberlites31st Yellowknife Geoscience Forum, p. 1-2.. (abst.)Northwest TerritoriesMineralogy - Group I, dataset
DS200412-0047
2003
Armstrong, J.P.Armstrong, J.P.Regional distribution of kimberlite indicator minerals, Slave Craton, Northwest Territories and Nunavut, Canada.31st Yellowknife Geoscience Forum, p. 1. (abst.)Canada, NunavutGeochemistry - KIM
DS200412-0048
2003
Armstrong, J.P.Armstrong, J.P., Barnett, R.L.The association of ZN chromite with Diamondiferous lamprophyres and diamonds: unique compositions as a guide to the diamond pote8 IKC Program, Session 8, POSTER abstractCanada, Northwest Territories, Ontario, WawaDiamond exploration
DS200412-0049
2003
Armstrong, J.P.Armstrong, J.P., Wilson, M., Barnett, R.L., Nowicki, T., Kjarsgaard, B.A.Paragenesis of primary magmatic Sr Ba Mg Ca carbonates from ultra fresh hypabyssal kimberlite, Lac de Gras kimberlite field, Sla8 IKC Program, Session 7, AbstractCanada, Northwest TerritoriesKimberlite petrogenesis Deposit - Ekati block
DS200412-0050
2003
Armstrong, J.P.Armstrong, J.P., Wilson, M., Barnett, R.L., Nowicki, T., Kjarsgaard, B.A.Mineralogy of calcite and calcite dolomite solid solution bearing hypabyssal kimberlites from the Lac de Gras kimberlite field,31st Yellowknife Geoscience Forum, p. 1-2.. (abst.)Canada, Northwest TerritoriesMineralogy - Group I, dataset
DS200812-0043
2007
Armstrong, J.P.Armstrong, J.P.An exploration update for the Aviat and Qilalugaq diamond projects, Melville Peninsula, Nunavut Stornoway35th. Yellowknife Geoscience Forum, Abstracts only p.1.Canada, NunavutExploration - brief overview
DS200812-0044
2007
Armstrong, J.P.Armstrong, J.P.The Renard kimberlites, Otish Mountains, Quebec: a development track project. Stornoway35th. Yellowknife Geoscience Forum, Abstracts only p.2.Canada, QuebecExploration - brief overview
DS200812-0045
2008
Armstrong, J.P.Armstrong, J.P.New advances in the geology of the Aviat kimberlites, Aviat project, Melville Peninsula, Nunavut.Northwest Territories Geoscience Office, p. 11. abstractCanada, Nunavut, Melville PeninsulaBrief overview - Stornoway
DS200912-0012
2009
Armstrong, J.P.Armstrong, J.P.An update on the Hammer and Aviat projects, Nunavut.37th. Annual Yellowknife Geoscience Forum, Abstracts p. 1-2.Canada, Nunavut, Coronation GulfDiamond exploration
DS200912-0322
2009
Armstrong, J.P.Hunt, L., Stachel, T., Armstrong, J.P., Simonetti, A.The Diamondiferous lithospheric mantle underlying the eastern Superior Craton: evidence from mantle xenoliths from the Renard kimberlite, Quebec.GAC/MAC/AGU Meeting held May 23-27 Toronto, Abstract onlyCanada, QuebecDeposit - Renard
DS201112-0862
2011
Armstrong, J.P.Riches, A.J.V., Pearson, D.G., Kjarsgaard, B.A., Jackson, S.E., Stachel, T., Armstrong, J.P.Deep lithosphere beneath the Rae Craton: peridotite xenoliths from Repulse Bay, Nunavut.Yellowknife Geoscience Forum Abstracts for 2011, abstract p. 74-75.Canada, Nunavut, Victoria Island, Parry PeninsulaMineralogy
DS201212-0023
2012
Armstrong, J.P.Armstrong, J.P., Fitzgerald, C., Kjarsgaard, B.A., Herman, L., Tappe, S.Kimberlites of the Coronation Gulf field, northern Slave Craton, Nunavut, Canada.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, NunavutDeposit - 26 kimberlites by name
DS201212-0340
2012
Armstrong, J.P.Johnson, C.N., Stachel, T., Muehlenbachs, K., Stern, R.A., Armstrong, J.P., EIMFThe micro/macro diamond relationship: a case study from the Artemisia kimberlite ( northern Slave Craton), Canada.Lithos, Vol. 148, pp. 86-97.Canada, Northwest TerritoriesDeposit - Artemisia
DS201212-0388
2012
Armstrong, J.P.Kupsch, B.G., Armstrong, J.P.Exploration and geology of the Qilalugaq kimberlites, Rae Isthmus, Nunavut, Canada.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, NunavutDeposit - Qilalugaq
DS201312-0523
2013
Armstrong, J.P.Kupsch, B., Armstrong, J.P.Exploration and geology of the Qilalugaq kimberlites, Rae Isthmus, Nunavut, Canada.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 67-78.Canada, NunavutDeposit - Qilalugaq
DS201412-0489
2013
Armstrong, J.P.Kupsch, B., Armstrong, J.P.Exploration and geology of the Qilalugaq kimberlites, Rae Isthmus, Nunavut, Canada.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 67-78.Canada, NunavutDeposit - Qilalugaq
DS201511-1846
2012
Armstrong, J.P.Johnson, C.N., Stachel, T., Muehlenbachs, K., Stern, R.A., Armstrong, J.P.The micro/macro diamond relationship: a case study from the Artemisia kimberlite ( Northern Slave Craton) Canada.Lithos, Vol. 148, pp. 86-97. Available pdfCanada, Northwest TerritoriesMicrodiamonds - responses

Abstract: Size frequency distributions are the principal tool for predicting the macro-diamond grade of new kimberlite discoveries, based on micro-diamonds (i.e., diamond = 0.5 mm) recovered from small exploration samples. Lognormal size frequency distributions – as observed for the Artemisia kimberlite (Slave Craton, Canada) – suggest a common source for micro- and macro-diamonds recovered from single samples, an implication that has never been conclusively tested. We analyzed 209 diamonds between 0.2 and 2 mm in size from the Artemisia kimberlite for their carbon isotopic compositions and nitrogen characteristics to determine the nature of the micro-/macro-diamond relationship.-Despite overall similarity in the d13C distributions of micro- and macro-diamonds – both are bimodal with peaks in classes - 5.0 to - 4.5‰ and - 3.5 to - 3.0‰ – rare diamonds with d13C between - 14.2 and - 24.5‰ of presumed eclogitic origin are restricted to macro-diamonds, whereas positive values are only observed for micro-diamonds. In addition, a shift in main mode and median value in d13C of about +1‰ is observed for micro- relative to macro-diamonds. Fundamental differences between micro- and macro-diamonds at Artemisia were revealed through the analysis of nitrogen concentrations: 68% of micro-diamonds are Type II (“nitrogen free”) versus 21% of macro-diamonds, and only 19% of micro-diamonds have nitrogen contents > 100 atomic ppm versus 43% of macro-diamonds. Similarly, the presence of a detectable hydrogen related peak (at 3107 cm- 1) increases from 40% for micro-diamonds to 94% for macro-diamonds.-Previous studies on diamond populations from individual deposits have documented that single batches of ascending kimberlite or lamproite magma sample multiple diamond subpopulations formed during distinct growth events in compositionally variable sources and at various depth levels. The Artemisia data clearly show that even over a fairly narrow size interval, spanning the micro- to macro-diamond transition, the specific diamond subpopulations present and their relative proportions may vary significantly with diamond size. At Artemisia, we conclude that the observed lognormal size distribution is not a reflection of an entirely common origin of micro- and macro-diamonds.
DS201601-0028
2016
Armstrong, J.P.Liu, J., Riches, A.J.V., Pearson, D.G., Luo, Y., Kienlen, B., Kjarsgaard, B.A., Stachel, T., Armstrong, J.P.Age and evolution of the deep continental root beneath the central Rae craton, northern Canada.Precambrian Research, Vol. 272, pp. 168-174.CanadaGeocronology, metasomatism, tectonics

Abstract: Canada is host to at least six separate cratons that comprise a significant proportion of its crustal extent. Of these cratons, we possess knowledge of the cratonic lithospheric roots beneath only the Slave craton and, to a lesser extent, the Superior craton, despite the discovery of many new diamond-bearing kimberlites in Canada's North. Here we present the first age, composition and geothermal information for kimberlite-borne peridotite xenoliths from two localities within the central Rae craton: Pelly Bay and Repulse Bay. Our aim is to investigate the nature and evolution of the deep lithosphere in these regions and to examine how events recorded in the mantle may or may not correlate with the complex history of crustal evolution across the craton. Peridotite xenoliths are commonly altered by secondary processes including serpentinization, silicification and carbonation, which have variably affected the major element compositions. These secondary processes, as well as mantle metasomatism recorded in pristine silicate minerals, however, did not significantly modify the relative compositions of platinum-group elements (PGE) and Os isotope ratios in the majority of our samples from Pelly Bay and Repulse Bay, as indicated by the generally high absolute PGE concentrations and mantle-like melt-depleted PGE patterns. The observed PGE signatures are consistent with the low bulk Al2O3 contents (mostly lower than 2.5%) of the peridotites, as well as the compositions of the silicate and oxide minerals. Based on PGE patterns and Os model ages, the peridotites from both localities can be categorized into three age groups: Archean (3.0-2.6 Ga overall; 2.8-2.6 Ga for Pelly Bay and 3.0-2.7 Ga for Repulse Bay), Paleoproterozoic (2.1-1.7 Ga), and "Recent" (<1 Ga, with model ages similar to the ca. 546 Ma kimberlite eruption age). The Archean group provides the first direct evidence of depleted Archean lithospheric mantle forming coevally with the overlying Archean crustal basement, indicating cratonization of the Rae during the Archean. The subtle difference in Os model ages between Pelly Bay and Repulse Bay coincides with the age difference between crustal basement rocks beneath these two areas, supporting the suggestion that the Rae craton was assembled by collision of separate two Archean blocks at 2.7-2.6 Ga. The Paleoproterozoic peridotites are interpreted to represent newly formed lithospheric mantle, most likely associated with regional-scale underplating during the 1.77-1.70 Ga Kivalliq-Nueltin event via removal of the lower portion of Archean lithospheric mantle followed by replacement with juvenile Paleoproterozoic lithospheric mantle. The existence of multiple age clusters in the lithosphere at each locality is consistent with the observation of present-day seismic lithospheric discontinuities (0540 and 0545) that indicate two or more layers of fossil lithospheric mantle fabric beneath this region. Our data define a shallow mantle lithosphere layer dominated by Archean depletion ages underlain by a layer of mixed Archean and Paleoproterozoic ages. This lithospheric mantle structure is probably a response to complex tectonic displacement of portions of the lithospheric mantle during Paleoproterozoic orogeny/underplating. The best equilibrated Archean and Paleoproterozoic peridotites at both Pelly Bay and Repulse Bay define a typical cratonic geotherm at the time of kimberlite eruption, with a ~200 km thick lithospheric root extending well into the diamond stability field, in keeping with the diamondiferous nature of the kimberlites. Such thick lithosphere remains in place to the present day as suggested by seismic and magnetotelluric studies (0540, 0545 and 0550). The metasomatically disturbed peridotites in the Rae lithospheric mantle, yielding model ages indistinguishable from kimberlite eruption, may represent parts of the Rae craton mantle root that show anomalous magnetotelluric signatures.
DS201602-0219
2016
Armstrong, J.P.Liu, J., Riches, A.J.V., Pearson, D.G., Luo, Y., Kienlen, B., Kjarsgaard, B.A., Stachel, T., Armstrong, J.P.Age and evolution of the deep continental root beneath the central Rae craton, northern Canada.Precambrian Research, Vol. 272, pp. 168-184.Canada, Northwest TerritoriesGeochronology

Abstract: Canada is host to at least six separate cratons that comprise a significant proportion of its crustal extent. Of these cratons, we possess knowledge of the cratonic lithospheric roots beneath only the Slave craton and, to a lesser extent, the Superior craton, despite the discovery of many new diamond-bearing kimberlites in Canada's North. Here we present the first age, composition and geothermal information for kimberlite-borne peridotite xenoliths from two localities within the central Rae craton: Pelly Bay and Repulse Bay. Our aim is to investigate the nature and evolution of the deep lithosphere in these regions and to examine how events recorded in the mantle may or may not correlate with the complex history of crustal evolution across the craton. Peridotite xenoliths are commonly altered by secondary processes including serpentinization, silicification and carbonation, which have variably affected the major element compositions. These secondary processes, as well as mantle metasomatism recorded in pristine silicate minerals, however, did not significantly modify the relative compositions of platinum-group elements (PGE) and Os isotope ratios in the majority of our samples from Pelly Bay and Repulse Bay, as indicated by the generally high absolute PGE concentrations and mantle-like melt-depleted PGE patterns. The observed PGE signatures are consistent with the low bulk Al2O3 contents (mostly lower than 2.5%) of the peridotites, as well as the compositions of the silicate and oxide minerals. Based on PGE patterns and Os model ages, the peridotites from both localities can be categorized into three age groups: Archean (3.0-2.6 Ga overall; 2.8-2.6 Ga for Pelly Bay and 3.0-2.7 Ga for Repulse Bay), Paleoproterozoic (2.1-1.7 Ga), and “Recent” (<1 Ga, with model ages similar to the ca. 546 Ma kimberlite eruption age). The Archean group provides the first direct evidence of depleted Archean lithospheric mantle forming coevally with the overlying Archean crustal basement, indicating cratonization of the Rae during the Archean. The subtle difference in Os model ages between Pelly Bay and Repulse Bay coincides with the age difference between crustal basement rocks beneath these two areas, supporting the suggestion that the Rae craton was assembled by collision of separate two Archean blocks at 2.7-2.6 Ga. The Paleoproterozoic peridotites are interpreted to represent newly formed lithospheric mantle, most likely associated with regional-scale underplating during the 1.77-1.70 Ga Kivalliq-Nueltin event via removal of the lower portion of Archean lithospheric mantle followed by replacement with juvenile Paleoproterozoic lithospheric mantle. The existence of multiple age clusters in the lithosphere at each locality is consistent with the observation of present-day seismic lithospheric discontinuities (0540 and 0545) that indicate two or more layers of fossil lithospheric mantle fabric beneath this region. Our data define a shallow mantle lithosphere layer dominated by Archean depletion ages underlain by a layer of mixed Archean and Paleoproterozoic ages. This lithospheric mantle structure is probably a response to complex tectonic displacement of portions of the lithospheric mantle during Paleoproterozoic orogeny/underplating. The best equilibrated Archean and Paleoproterozoic peridotites at both Pelly Bay and Repulse Bay define a typical cratonic geotherm at the time of kimberlite eruption, with a ~200 km thick lithospheric root extending well into the diamond stability field, in keeping with the diamondiferous nature of the kimberlites. Such thick lithosphere remains in place to the present day as suggested by seismic and magnetotelluric studies (0540, 0545 and 0550). The metasomatically disturbed peridotites in the Rae lithospheric mantle, yielding model ages indistinguishable from kimberlite eruption, may represent parts of the Rae craton mantle root that show anomalous magnetotelluric signatures.
DS201710-2211
2017
Armstrong, J.P.Armstrong, J.P., Gababotse, J.Karowe diamond mine.11th International Kimberlite Field Trip Guide, Sept. 19p. PdfAfrica, Botswanadeposit - Karowe
DS201809-2082
2018
Armstrong, J.P.Sarkar, C., Kjarsgaard, B.A., Pearson, D.G., Heaman, L.M., Locock, A.J., Armstrong, J.P.Geochronology, classification and mantle source characteristics of kimberlites and related rocks from the Rae craton, Melville Peninsula, Nunavut, Canada.Mineralogy and Petrology, doi.org/10.1007/ s00710-018-0632-5 20p.Canada, Nunavut, Melville Peninsuladeposit - Pelly Bay, Darby, Aviat, Qilalugaq

Abstract: Detailed geochronology along with petrographic, mineralogical and geochemical studies have been conducted on recently found diamond-bearing kimberlitic and related rocks in the Rae Craton at Aviat and Qilalugaq, Melville Peninsula, north-east Canada. Magmatic rocks from the Aviat pipes have geochemical (both bulk rock and isotopic) and mineralogical signatures (e.g., core to rim Al and Ba enrichment in phlogopite) similar to Group I kimberlite. In contrast, Aviat intrusive sheets are similar to ‘micaceous’ Group II kimberlite (orangeite) in their geochemical and mineralogical characteristics (e.g., phlogopite and spinel compositions, highly enriched Sr isotopic signature). Qilalugaq rocks with the least crustal contamination have geochemical and mineralogical signatures [e.g., high SiO2, Al2O3 and H2O; low TiO2 and CO2; less fractionated REE (rare earth elements), presence of primary clinopyroxene, phlogopite and spinel compositions] that are similar to features displayed by olivine lamproites from Argyle, Ellendale and West Greenland. The Naujaat dykes, in the vicinity of Qilalugaq, are highly altered due to extensive silicification and carbonation. However, their bulk rock geochemical signature and phlogopite chemistry are similar to Group I kimberlite. U-Pb perovskite geochronology reveals that Aviat pipes and all rocks from Qilalugaq have an early Cambrian emplacement age (540-530 Ma), with the Aviat sheets being ~30 Ma younger. This volatile-rich potassic ultramafic magmatism probably formed by varying degrees of involvement of asthenospheric and lithospherically derived melts. The spectrum of ages and compositions are similar to equivalent magmatic rocks observed from the nearby north-eastern North America and Western Greenland. The ultimate trigger for this magmatism could be linked to Neoproterozoic continental rifting during the opening of the Iapetus Ocean and breakup of the Rodinia supercontinent.
DS200512-1082
2004
Armstrong, K.Thomas, E., Woad, G., Armstrong, K.New kimberlite discoveries at Aviat and Wales Island on the Melville Peninsula, Nunavut.32nd Yellowknife Geoscience Forum, Nov. 16-18, p.80-81 (talk)Canada, NunavutCompany overview - Stornaway
DS201910-2246
2019
Armstrong, K.Bureau, H., Raepsat, V., Esteve, I., Armstrong, K., Manthilake, G.Replicate mantle diamonds.Goldschmidt2019, 1p. AbstractMantlediamond genesis

Abstract: Still today, diamond growth in the mantle is difficult to understand. It may implicate different processes but there is an agreement to involve fluids as diamonds parents. The composition of these fluids is supposed to be variable depending of the the settings and depths. Natural diamonds also exhibit dissolution features, possibly mantle-derived and not only due to kimberlite-induced resorption during magma ascent [1]. We present experimental results devoted to understand diamond growth versus dissolution mechanisms in the lithosphere. Experiments are performed using multianvil presses at 7 GPa, 1300-1675°C for a few hours (4 to 27 hrs). As starting materials we use mixtures of water, carbonates, natural lherzolite or MORB, graphite and diamonds seeds resulting in hydrous-carbonate-silicate fluids at high pressure and temperature. For similar pressure and temperature conditions, results show that diamonds are formed or dissolved in these fluids, depending on the redox conditions. Focussed ion beam preparations of the diamonds evidence that when they grow, they trap multi-phased inclusions similar to those observed in fibrous, coated and monocrystalline natural diamonds, in agreement with previous studies [2-4].
DS1995-0057
1995
Armstrong, K.A.Armstrong, K.A.Investigation of the spinel mineralogy of the C14 kimberlite, KirklandLake, Ontario.Queen's University of, MSc.OntarioMineralogy, Deposit - C14
DS1995-0058
1995
Armstrong, K.A.Armstrong, K.A.An investigation of the spinel mineralogy of the C14 Kimberlite, KirklandLake, Ontario.Queen's University of, Msc. ThesisOntarioMineralogy, Deposit - C14
DS1995-0059
1995
Armstrong, K.A.Armstrong, K.A., Roeder, P.L., Helmstaedt, H.H.The spinel mineralogy of the C14 kimberlite, Kirkland Lake, OntarioProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 14-16.OntarioMineralogy -spinel, Deposit - C14 Kirkland Lake
DS1997-0040
1997
Armstrong, K.A.Armstrong, K.A., Roeder, P.L., Helmstaedt, H.H.Composition of spinels in the Carbon 14 kimberlite, Kirkland Lake Ontario.Russian Geology and Geophysics, Vol. 38, No. 2, pp. 454-466.OntarioGeochemistry, Deposit -C 14
DS2003-0032
2003
Armstrong, K.A.Armstrong, K.A.Preliminary exploration results for Inuit owned lands of the West Kitikmeot31st Yellowknife Geoscience Forum, p. 2-3. (abst.)NunavutMineralogy - baddelyite
DS2003-0033
2003
Armstrong, K.A.Armstrong, K.A., Nowicki, T., Read, G.H.Kimberlite AT-56: a mantle sample from the north central Superior Craton, Canada8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractOntario, James Bay LowlandsDeposit - Attawapiskat
DS200412-0051
2003
Armstrong, K.A.Armstrong, K.A.Preliminary exploration results for Inuit owned lands of the West Kitikmeot.31st Yellowknife Geoscience Forum, p. 2-3. (abst.)Canada, NunavutMineralogy - baddelyite
DS200412-0052
2003
Armstrong, K.A.Armstrong, K.A., Nowicki, T., Read, G.H.Kimberlite AT-56: a mantle sample from the north central Superior Craton, Canada.8 IKC Program, Session 8, POSTER abstractCanada, Ontario, Attawapiskat, James Bay LowlandsDiamond exploration Deposit - Attawapiskat
DS200412-0053
2004
Armstrong, K.A.Armstrong, K.A., Nowicki, T.E., Read, G.H.Kimberlite AT-56: a mantle sample from the north central Superior Craton, Canada.Lithos, Vol. 77, 1-4, Sept. pp. 695-704.Canada, Ontario, Attawapiskat, James Bay LowlandsWebsteritic mantle, eclogite, Ni thermometry
DS2002-1122
2002
Armstrong, L.Mysen, B.O., Armstrong, L.Solubility behaviour of alkali aluminosilicate components in aqueous fluids and silicate melts at high pressure and temperature.Geochimica et Cosmochimica Acta, Vol.66,12, June pp. 2287-98.GlobalGeochemistry - melt
DS200912-0805
2009
Armstrong, L.S.Walter, M.J., Bulanova, G.P., Armstrong, L.S., Keshav, S., Blundy, Gudfinnsson, Lord, Lennie, Clark, GobboPrimary carbonatite melt from deeply subducted oceanic crust.Nature, Vol. 459, July 31, pp. 622-626.South America, Brazil, MantleMelting, geochemistry
DS201012-0079
2010
Armstrong, L.S.Bulanova, G.P., Walter, M.J., Smith, C.B.,Kohn, C.C.,Armstrong, L.S., Blundy, J.,Gobbo, L.Mineral inclusions in sublithospheric diamonds from Collier 4 kimberlite pipe, Juina, Brazil: subducted protoliths, carbonated melts and primary kimberlite ..Contributions to Mineralogy and Petrology, Vol. 160, 4, pp. 489-50.South America, BrazilMagmatism
DS201112-0029
2011
Armstrong, L.S.Armstrong, L.S., Walter, M.J.TAPP: retrograde Mg perovskite from subducted lithosphere.Goldschmidt Conference 2011, abstract p.453.MantleTAPP inclusions - diamond
DS201212-0024
2012
Armstrong, L.S.Armstrong, L.S., Walter, M.J.Tetragonal almandine pyrope phase ( TAPP): retrograde Mg-perovskite from subducted oceanic crust?European Journal of Mineralogy, Vol. 24, 4, pp. 587-597.TechnologyPerovskite
DS201212-0025
2012
Armstrong, L.S.Armstrong, L.S., Walter, M.J., Tuff, J.R., Lord, O.T., Lennie, A.R., Kleppe, A.K., Clark, S.M.Perovskite phase relations in the system CaO-MgO-TiO2-Si02 and implications for deep mantle lithologies.Journal of Petrology, Vol. 53, 3, pp. 611-635.MantlePerovskite
DS201212-0133
2012
Armstrong, L.S.Corgne, A., Armstrong, L.S., Keshav, S., Fei, Y., McDonough, W.F., Minarik, W.G., Moreno, K.Trace element partitioning between majoritic garnet and silicate melt at 10-17 Gpa: implications for deep mantle processes.Lithos, Vol. 148, pp. 128-141.Africa, South Africa, GuineaDeposit - Kankan
DS201801-0011
2017
Armstrong, L.S.Dalou, C., Hirschmann, M.M., von der Handt, A., Mosenfelder, J., Armstrong, L.S.Nitrogen and carbon fractionation during core-mantle differentiation at shallow depth.Earth and Planetary Science Letters, Vol. 458, 1, pp. 141-151.Mantlecarbon

Abstract: One of the most remarkable observations regarding volatile elements in the solar system is the depletion of N in the bulk silicate Earth (BSE) relative to chondrites, leading to a particularly high and non-chondritic C:N ratio. The N depletion may reflect large-scale differentiation events such as sequestration in Earth's core or massive blow off of Earth's early atmosphere, or alternatively the characteristics of a late-added volatile-rich veneer. As the behavior of N during early planetary differentiation processes is poorly constrained, we determined together the partitioning of N and C between Fe–N–C metal alloy and two different silicate melts (a terrestrial and a martian basalt). Conditions spanned a range of fO2 from ?IW-0.4 to ?IW-3.5 at 1.2 to 3 GPa, and 1400?°C or 1600?°C, where ?IW is the logarithmic difference between experimental fO2 and that imposed by the coexistence of crystalline Fe and wüstite. N partitioning ( ) depends chiefly on fO2, decreasing from to with decreasing fO2. also decreases with increasing temperature and pressure at similar fO2, though the effect is subordinate. In contrast, C partition coefficients () show no evidence of a pressure dependence but diminish with temperature. At 1400?°C, partition coefficients increase linearly with decreasing fO2 from to At 1600?°C, however, they increase from ?IW-0.7 to ?IW-2 ( to ) and decrease from ?IW-2 to ?IW-3.3 . Enhanced C in melts at high temperatures under reduced conditions may reflect stabilization of C–H species (most likely CH4). No significant compositional dependence for either N or C partitioning is evident, perhaps owing to the comparatively similar basalts investigated. At modestly reduced conditions (?IW-0.4 to -2.2), N is more compatible in core-forming metal than in molten silicate ( ), while at more reduced conditions (?IW-2.2 to ?IW-3.5), N becomes more compatible in the magma ocean than in the metal phase. In contrast, C is highly siderophile at all conditions investigated (). Therefore, sequestration of volatiles in the core affects C more than N, and lowers the C:N ratio of the BSE. Consequently, the N depletion and the high C:N ratio of the BSE cannot be explained by core formation. Mass balance modeling suggests that core formation combined with atmosphere blow-off also cannot produce a non-metallic Earth with a C:N ratio similar to the BSE, but that the accretion of a C-rich late veneer can account for the observed high BSE C:N ratio.
DS1989-0036
1989
Armstrong, M.Armstrong, M., Champigny, N.A study of kriging small blocksThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 82, No. 923, March pp. 128-133. Database # 17752GlobalGeostatistics, Kriging
DS1992-0043
1992
Armstrong, M.Armstrong, M.Positive definiteness is not enoughMathematical Geology, Vol. 24, No. 1, pp. 135-144GlobalGeostatistics, VariograM.
DS1994-0036
1994
Armstrong, M.Allard, D., Armstrong, M., Kleingeld, W.J.The need for a connectivity index in mining geostatisticsGeostatistics for the Next Century, pp. 293-302, Selective Mining UnitGlobalGeostatistics, Connectivity Index
DS1994-0064
1994
Armstrong, M.Armstrong, M.Is research in mining geostats as dead as a dodo?Geostatistics for the Next Century, pp. 303-312GlobalGeostatistics, Reserve estimates
DS1994-0281
1994
Armstrong, M.Champigny, N., Armstrong, M.An overview of reserve estimation problems .The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 87, No. 977, February pp. 23-25GlobalGeostatistics, Ore reserves
DS1997-0041
1997
Armstrong, M.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
DS1991-0124
1991
Armstrong, R.Bizzi, L.A., Smith, C.B., Meyer, H.O.A., Armstrong, R., De WitMesozoic kimberlites and related alkalic rocks in south-western Sao Francisco craton, Brasil: a case of local mantle reservoirs and theirinteractionProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 17-19BrazilCraton -Sao Francisco, Monticellite, geothermometry, isotopes
DS1994-0167
1994
Armstrong, R.Bizzi, L.A., Smith, C.B., DeWitt, M.J., Armstrong, R., Meyer, H.O.A.Mesozoic kimberlites and related alkaline rocks in southwest Sao Francisco Brasil: a case for local mantle reservoirs and their interaction.Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 156-171.BrazilAlkaline rocks, San Francisco craton
DS1998-0014
1998
Armstrong, R.Ahall, K.I., Cornell, D.H., Armstrong, R.Ion probe zircon dating of metasedimentary units across the Skagerrak: new constraints early Mesoproterozoic.Precambrian Research, Vol. 87, No. 3-4, Feb. 1, pp. 117-134Sweden, Norway, Finland, Baltic ShieldGeochronology
DS1998-0045
1998
Armstrong, R.Armstrong, R., De Wit, M.J., et al.Cape Town's Table Mountain reveals rapid Pan-African uplift of its basementrocks.Journal of African Earth Sciences, Vol. 27, 1A, p. 10. AbstractSouth AfricaGondwana, tectonics, Pan-African rift
DS1998-1471
1998
Armstrong, R.Tompkins, L., Taylor, W., Ramsay, R., Armstrong, R.The mineralogy and geochemistry of the Kamafugitic Tres Barras intrusion, Mat a da Corda, Minas Gerais, Brasil.7th International Kimberlite Conference Abstract, pp. 920-2.Brazil, Minas GeraisLeucitites, kamafugites, Deposit - Tres Barras
DS2000-0866
2000
Armstrong, R.Schersten, A., Areback, H., Armstrong, R.Dating mafic - ultramafic intrusions by ion microprobing contact melt zircon: examples from southwest...Contrib. Min. Pet., Vol. 139, No. 1, pp. 115-SwedenGeochronology
DS2001-0753
2001
Armstrong, R.McCourt, S., Armstrong, R.The architecture and evolution of the northern Kaapvaal Limpopo Terrane, South Africa.Slave-Kaapvaal Workshop, Sept. Ottawa, 5p. abstractSouth AfricaTectonics, Limpopo Belt
DS2002-0237
2002
Armstrong, R.Camacho, A., Hensen, B.J., Armstrong, R.Isotopic test of a thermally driven intraplate orogenic model, AustraliaGeology, Vol. 30, 10, Oct. pp. 887-90.AustraliaOrogenesis, basins, geothermometry
DS2003-1081
2003
Armstrong, R.Piuzana, D., Pimentel, M.M., Fuck, R.A., Armstrong, R.SHRIMP U Pb and Sm Nd dat a for the Araxa group and associated magmatic rocks:Precambrian Research, Vol. 125, 1-2, pp. 139-60.BrazilMagmatism - Carbonatite
DS200412-1554
2003
Armstrong, R.Piuzana, D., Pimentel, M.M., Fuck, R.A., Armstrong, R.SHRIMP U Pb and Sm Nd dat a for the Araxa group and associated magmatic rocks: constraints for the age of sedimentation and geodyPrecambrian Research, Vol. 125, 1-2, pp. 139-60.South America, Brazil, BahiaGeochronology Magmatism - carbonatites
DS200612-0112
2006
Armstrong, R.Becket, T., Schreiber, U., Kampunzu, A.B., Armstrong, R.Mesoproterozoic rocks of Namibia and their plate tectonic setting.Journal of African Earth Sciences, Vol. 46, 1-2, pp. 112-140.Africa, NamibiaTectonics
DS201012-0551
2010
Armstrong, R.Oliveira, E.P., McNaughton, N.J., Armstrong, R.Mesoarchean to Paleoproterozoic growth of the northern segment of the Itabuna Salvador Curaca orogen, Sao Francisco Craton, Brazil.The evolving continents: understanding processes of continental growth, Geological Society of London, Vol. 338, pp. 263-286.South America, BrazilCraton, geodynamics
DS201212-0124
2012
Armstrong, R.Chemale, F., Dussin, I.A., Alkmim, F.F., Martins, M.S., Queiroga, G., Armstrong, R., Santos, M.N.Unravelling a Proterozoic basin history through detrital zircon geochronology: the case of the Esponhaco Supergroup, Minas Gerais, Brazil.Gondwana Research, Vol. 22, 1, pp. 200-206.South America, Brazil, Minas GeraisSan Francisco Congo paleocraton, diamond bearing sequences
DS201212-0339
2012
Armstrong, R.Jelsma, H.,Krishnan, S.U., Perritt, S.,Kumar, M., Preston, R., Winter, F., Lemotlo, L., Costa, J., Van der Linde, G., Facatino, M., Posser, A., Wallace, C., Henning, A., Joy, S., Chinn, I., Armstrong, R., Phillips, D.Kimberlites from central Angola: a case stidy of exploration findings.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, AngolaOverview of kimberlites
DS201312-0314
2013
Armstrong, R.Giuliani, A., Phillips, D., Kendrick, M.K., Maas, R., Greig, A., Armstrong, R., Felgate, M.R., Kamenetsky, V.S.Dating mantle metasomatism: a new tool ( U/PB LIMA Titanate) and an imposter ( 40Ar/39Ar phlogopite).Goldschmidt 2013, AbstractMantleMetasomatism
DS201412-0427
2013
Armstrong, R.Jelsma, H., Krishnan, U., Perritt, S., Preston, R., Winter, F., Lemotlo, L., van der Linde, G., Armstrong, R., Phillips, D., Joy, S., Costa, J., Facatino, M., Posser, A., Kumar, M., Wallace, C., Chinn, I., Henning, A.Kimberlites from central Angola: a case study of exploration findings.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 173-190.Africa, AngolaExploration - kimberlites
DS201502-0123
2014
Armstrong, R.White, L., Graham, I., Armstrong, R., Hall, R.Tracing the source of Borneo's Cempaka deposit.American Geophysical Union, December - Fall meeting in San Francisco, abstractAsia, KalimantanDeposit - Cempaka
DS201605-0907
2016
Armstrong, R.Sutherland, L., Graham, I., Yaxley, G., Armstrong, R.Major zircon megacryst suites of the Indo-Pacific lithospheric margin (ZIP) and their petrogenetic and regional implications.Mineralogy and Petrology, Vol. 110, 2, pp. 399-420.IndonesiaMegacrysts

Abstract: Zircon megacrysts (± gem corundum) appear in basalt fields of Indo-Pacific origin over a 12,000 km zone (ZIP) along West Pacific continental margins. Age-dating, trace element, oxygen and hafnium isotope studies on representative zircons (East Australia-Asia) indicate diverse magmatic sources. The U-Pb (249 to 1 Ma) and zircon fission track (ZFT) ages (65 to 1 Ma) suggest thermal annealing during later basalt transport, with?
DS1985-0714
1985
Armstrong, R.A.Watkeys, M.K., Armstrong, R.A.The importance of being alkaline-deformed late Archeanlamprophyricdykes, Central zone, Limpopo beltTransactions Geological Society of South Africa, Vol. 88, pt. 2, May-August pp. 195-206South AfricaLamprophyre, Dike
DS1992-0352
1992
Armstrong, R.A.De Wit, M.J., Roering, C., Hart, R.J., Armstrong, R.A., et al.Formation of an Archean continent #1Nature, Vol. 357, No. 6379, June 18, pp. 553-562South AfricaArchean continent, Structure
DS1994-0166
1994
Armstrong, R.A.Bizzi, L.A., Smith, C.B., De Wit, M., Macdonald, I., Armstrong, R.A.Isotopic characteristics of the lithospheric mantle underlying the southwest Sao Francisco craton margin, Brasil.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 227-255.BrazilGeochronology, Craton
DS1996-0043
1996
Armstrong, R.A.Armstrong, R.A.Unravelling the assembly of the most Diamondiferous craton - a case studyof the Kaapvaal Craton.Australia Nat. University of Diamond Workshop July 29, 30. abstracts, 2p.South Africa, southern AfricaCraton, Geochronology -zircon
DS1998-0046
1998
Armstrong, R.A.Armstrong, R.A., Moore, R.O.Rubidium-Strontium ages on kimberlites from the Lac de Gras area, Northwest Canada.South African Journal of Geology, Vol. 101, No. 2, June pp. 155-158.Northwest TerritoriesGeochronology, Lac de Gras area
DS1998-0975
1998
Armstrong, R.A.McCourt, S., Armstrong, R.A.Shrimp uranium-lead (U-Pb) zircon geochronology of granites from the Central Zone, LimpopoBelt: implications age Orogeny.South African Journal of Geology, Vol. 101, No. 4, Dec. 1, pp. 329-South AfricaGeochronology, Limpopo Orogeny - not specific to diamonds
DS2000-0270
2000
Armstrong, R.A.Elworthy, T., Eglinton, B.M., Armstrong, R.A., Moyes, A.Rubidium-Strontium isotope constraints on timing of late to post-Archean tectonometamorphism- Kaapvaal Craton.Journal of African Earth Sciences, Vol. 30, No.3, pp. 641-50.South Africa, BotswanaGeochronology - metamorphism, Craton - Kaapvaal
DS2000-0518
2000
Armstrong, R.A.Konzett, J., Armstrong, R.A., Gunther, D.Modal metasomatism in the Kaapvaal Craton lithosphere: constraints on timing and genesis of uranium-lead (U-Pb) zircon....Contributions to Mineralogy and Petrology, Vol. 139, No. 6, pp. 704-19.South AfricaXenoliths, metasomatized peridotites, MARID.
DS2000-0763
2000
Armstrong, R.A.Phillips, D., Kiviets, G.B., Armstrong, R.A.Geochronology of kimberlites and related rocks: a synthesis of available radiometric techniques.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000, 3p. abstract.Australia, South AfricaGeochronology - age determinations, Methodology
DS2003-0371
2003
Armstrong, R.A.Eglinton, B.M., Armstrong, R.A.Geochronological and isotopic constraints on the Mesoproterozoic Namaqa Natal beltPrecambrian Research, Vol. 125, No. 3-4, pp. 179-189.South AfricaGeochronology
DS2003-1077
2003
Armstrong, R.A.Pimentel, M.M., Dantas, E.L., Fuck, R.A., Armstrong, R.A.Shrimp and conventional U Pb age, Sm Nd isotopic characteristics and tectonicAnais Academia Brasileira de Ciencias, Vol. 75, 1, pp. 97-108.Brazil, GoiasGeochronology, Alkaline rocks
DS200412-0505
2004
Armstrong, R.A.Eglington, B.M., Armstrong, R.A.The Kaapvaal Craton and adjacent orogens, southern Africa: a geochronological database and overview of the geological developmenSouth African Journal of Geology, Vol. 107, 1/2, pp. 13-32.Africa, South AfricaGeochronology - craton
DS200412-0506
2003
Armstrong, R.A.Eglinton, B.M., Armstrong, R.A.Geochronological and isotopic constraints on the Mesoproterozoic Namaqa Natal belt, evidence from deep borehole intersections inPrecambrian Research, Vol. 125, no. 3-4, pp. 179-189.Africa, South AfricaGeochronology
DS200412-1222
2004
Armstrong, R.A.Mapeo, R.B.M., Armstrong, R.A., Kampunzu, A.B., Ramokate, L.V.SHRIMP U Pb zircon ages of granitoids from the western domain of the Kaapvaal Craton, southeastern Botswana: implications for crSouth African Journal of Geology, Vol. 107, 1/2, pp. 159-172.Africa, BotswanaGeochronology, tectonics
DS200412-1548
2003
Armstrong, R.A.Pimentel, M.M., Dantas, E.L., Fuck, R.A., Armstrong, R.A.Shrimp and conventional U Pb age, Sm Nd isotopic characteristics and tectonic significance of the K rich Itapuranga Suite in GoiAnais Academia Brasileira de Ciencias, Vol. 75, 1, pp. 97-108.South America, Brazil, GoiasGeochronology Alkaline rocks
DS200612-0037
2006
Armstrong, R.A.Armstrong, R.A., Lana, C., Reimold, W.U., Gibson, R.L.Shrimp zircon age constraints on Mesoarchean crustal development in the Vredefort dome, central Kaapvaal Craton, South Africa.Geological Society of America, Special Paper 405, pp. 233-254.Africa, South AfricaGeochronology
DS200612-0845
2006
Armstrong, R.A.Macambira, M.J.B., Armstrong, R.A., Silva, D.C.C., Camelo, J.F.The Archean Paleoproterozoic boundary in Amazonian Craton: new isotope evidence for crustal growth.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 2, abstract only.South America, BrazilGeochronology, craton
DS200612-1107
2005
Armstrong, R.A.Poujol, M., Kiefer, R., Robb, L.J., Anhaesser, C.R., Armstrong, R.A.New U pb dat a on zircons from the Amalia greenstone belt southern Africa: insights into the Neoarchean evolution of the Kaapvaal Craton.South African Journal of Geology, Vol. 108, 3, pp. 317-332.Africa, South AfricaGeochronology
DS201012-0248
2010
Armstrong, R.A.Grantham, G.H., Manhica, A.D.S.T., Armstrong, R.A., Kruger, F.J., Loubser, M.New SHRIMP, Rb/Sr and Sm/Nd isotope and whole rock chemical dat a from central Mozambique and western Dronning Maud Land: implications for eastern KalahariJournal of African Earth Sciences, Vol. 59, 1, pp.74-100.Africa, Mozambique, AntarcticaCraton, amalgamation of Gondwana
DS201012-0479
2009
Armstrong, R.A.Mbedi, E., Kampunzu, A.B., Armstrong, R.A.Neoproterozoic inheritance during Cainozoic rifting in the western and southwestern branches of the East African Rift system: evidence from carbonatite alkalineTanzanian Journal of Earth Science, Vol. 1, Dec. pp. 29-37.Africa, TanzaniaCarbonatite, Nachendezwaya
DS201112-0232
2011
Armstrong, R.A.Da Silva Filio, A.F., Guimaraes, I.P., Armstrong, R.A.SHRIMP U Pb geochronology of Neoproterzoic Rio Una sequence, NE Brazil and the Rodinia break-up.Goldschmidt Conference 2011, abstract p.724.South America, Brazil, AfricaGondwana - Borborema Province
DS201312-0593
2013
Armstrong, R.A.McCourt, S., Armstrong, R.A., Jelsma, H., Mapeo, R.B.M.New U-Pb SHRIMP ages from the Lubango region, sw Angola: insights into the Paleoproterozoic evolution of the Angolan shield, southern Congo craton, Africa.Journal of the Geological Society, Vol. 170, pp. 353-363.Africa, AngolaGeochronology
DS201412-0296
2014
Armstrong, R.A.Giuliani, G., Phillips, D., Maas, R., Woodhead, J.D., Kendrick, M.A., Greig, A., Armstrong, R.A., Chew, D., Kamenetsky, V.S., Fiorentini, M.I.LIMA U-Pb ages link lithospheric mantle metasomatism to Karoo magmatism beneath the Kimberley region, South Africa.Earth and Planetary Science Letters, Vol. 401, pp. 132-147.Africa, South AfricaKimberlite
DS201603-0431
2016
Armstrong, R.A.White, L.T., Graham, I., Tanner, D., Hall, R., Armstrong, R.A., Yaxley, G., Barron, L.The provenance of Borneo's enigmatic alluvial diamonds: a case study from Cempaka, SE Kalimantan.Gondwana Research, in press available 22p.Asia, KalimantanAlluvials, diamonds

Abstract: Gem-quality diamonds have been found in several alluvial deposits across central and southern Borneo. Borneo has been a known source of diamonds for centuries, but the location of their primary igneous source remains enigmatic. Many geological models have been proposed to explain their distribution, including: the diamonds were derived from a local diatreme; they were brought to the surface through ophiolite obduction or exhumation of UHP metamorphic rocks; they were transported long distances southward via major Asian river systems; or, they were transported from the Australian continent before Borneo was rifted from its northwestern margin in the Late Jurassic. To assess these models, we conducted a study of the provenance of heavy minerals from Kalimantan's Cempaka alluvial diamond deposit. This involved collecting U Pb isotopic data, fission track and trace element geochemistry of zircon as well as major element geochemical data of spinels and morphological descriptions of zircon and diamond. The results indicate that the Cempaka diamonds were likely derived from at least two sources, one which was relatively local and/or involved little reworking, and the other more distal which records several periods of reworking. The distal diamond source is interpreted to be diamond-bearing pipes that intruded the basement of a block that: (1) rifted from northwest Australia (East Java or SW Borneo) and the diamonds were recycled into its sedimentary cover, or: (2) were emplaced elsewhere (e.g. NW Australia) and transported to a block (e.g. East Java or SW Borneo). Both of these scenarios require the diamonds to be transported with the block when it rifted from NW Australia in the Late Jurassic. The local source could be diamondiferous diatremes associated with eroded Miocene high-K alkaline intrusions north of the Barito Basin, which would indicate that the lithosphere beneath SW Borneo is thick (~ 150 km or greater). The ‘local’ diamonds could also be associated with ophiolitic rocks that are exposed in the nearby Meratus Mountains.
DS201803-0450
2014
Armstrong, R.A.Giuliani, A., Phillips, D., Maas, R., Woodhead, J.D., Kendrick, M.A., Greig, A., Armstrong, R.A., Chew, D., Kamenetsky, V.S., Fiorentini, M.L.LIMA U-Pb ages link lithospheric mantle metasomatism to Karoo magmatism beneath the Kimberley region, South Africa.Earth and Planetary Science Letters, Vol. 401, pp. 132-147.Africa, South Africametasomatism

Abstract: The Karoo igneous rocks (174-185 Ma) of southern Africa represent one of the largest continental flood basalt provinces on Earth. Available evidence indicates that Karoo magmas either originated in the asthenosphere and were extensively modified by interaction with the lithospheric mantle prior to emplacement in the upper crust; or were produced by partial melting of enriched mantle lithosphere. However, no direct evidence of interaction by Karoo melts (or their precursors) with lithospheric mantle rocks has yet been identified in the suites of mantle xenoliths sampled by post-Karoo kimberlites in southern Africa. Here we report U-Pb ages for lindsleyite-mathiasite (LIMA) titanate minerals (crichtonite series) from three metasomatised, phlogopite and clinopyroxene-rich peridotite xenoliths from the ~84 Ma Bultfontein kimberlite (Kimberley, South Africa), located in the southern part of the Karoo magmatic province. The LIMA minerals appear to have formed during metasomatism of the lithospheric mantle by fluids enriched in HFSE (Ti, Zr, Hf, Nb), LILE (K, Ba, Ca, Sr) and LREE. LIMA U-Pb elemental and isotopic compositions were measured in situ by LA-ICP-MS methods, and potential matrix effects were evaluated by solution-mode analysis of mineral separates. LIMA minerals from the three samples yielded apparent U-Pb ages of , and (). A single zircon grain extracted from the ~190 Ma LIMA-bearing sample produced a similar U-Pb age of , within uncertainty of the LIMA ages. These data provide the first robust evidence of fluid enrichment in the lithospheric mantle beneath the Kimberley region at ~180-190 Ma, and suggest causation of mantle metasomatism by Karoo melts or their precursor(s). The results further indicate that U-Pb dating of LIMA minerals provides a new, accurate tool for dating metasomatic events in the lithospheric mantle.
DS1960-1067
1969
Armstrong, R.L.Armstrong, R.L.K-ar Dating of Laccolithic Centres of the Colorado Plateau And Vicinity.Geological Society of America (GSA) Bulletin., Vol. 80, PP. 2081-2086.Colorado PlateauKimberlite, Rocky Mountains
DS1970-0929
1974
Armstrong, R.L.Hills, F.A., Armstrong, R.L.Geochronology of Precambrian Rocks in the Laramie Range And implications for the Tectonic Framework of Precambrian Southern Wyoming.Precambrian Research, Vol. 1, PP. 213-225.United States, Wyoming, Rocky Mountains, Medicine Bow MountainsBlank
DS1987-0003
1987
Armstrong, R.L.Agyei, E.K., Van Landewijk, J.E.J.M., Armstrong, R.L., Harakal, J.E.Rubidium-strontium and potassium-argon geochronometry of southeasternGhanaJournal of African Earth Science, Vol. 6, No. 2, pp. 153-161GhanaCarbonatite
DS1991-0032
1991
Armstrong, R.L.Armstrong, R.L.A brief history of geochronology and radiogenic isotope studiesMineralogical Association of Canada -Short Course Handbook, Vol. 19, Chapter 1, pp. 1-26GlobalGeochronology, Radiogenic
DS1991-0033
1991
Armstrong, R.L.Armstrong, R.L.The persistent myth of crustal growthAustralian Journal of Earth Sciences, Vol. 38, December pp. 613-630MantleCrust, Geochronology
DS1991-1159
1991
Armstrong, R.L.Min Sun, Armstrong, R.L., Maxwell, R.J.Proterozoic mantle under Quesnellia: variably reset rubidium-strontium (Rb-Sr) mineral isochrons in ultramafic nodules carried up in Cenozoic volcanic vents of the s. OminecaBeltCanadian Journal of Earth Sciences, Vol. 28, No. 8, August pp. 1239-1253British ColumbiaGeochronology, Proterozoic mantle
DS1993-1174
1993
Armstrong, W.P.Owens, O., Armstrong, W.P.Ore reserves -the four CsThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Exploration and Mining Geology, Vol. 2, No. 1, January pp. 49-52GlobalGeostatistics, Ore reserves
DS1994-1323
1994
Armstrong, W.P.Owens, O., Armstrong, W.P.Ore reserves -the four C's. previously listed in 1992 as a preprintThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 87, No. 979, April pp. 52-54GlobalGeostatistics, Ore reserves
DS201412-0015
2014
Armytage, R.M.G.Armytage, R.M.G., Brandon, A.D., Peslier, A.H., Lapen, T.J.Osmium isotope evidence for Early to Middle Proterozoic mantle lithosphere stabilization and concommitant production of juvenile crust in Dish Hill, CA peridotite xenoliths.Geochimica et Cosmochimica Acta, Vol. 137, pp. 113-133.United States, CaliforniaSCLM, subduction
DS200612-0038
2006
Arnadottir, T.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
DS201912-2790
2019
Arnaud, F.Jacq, K., Giguet-Covex, C., Sabatier, P., Perrette, Y., Fanget, B., Coquin, D., Debret, M., Arnaud, F.High resolution grain size distribution of sediment core with hyperspectral imaging. ( not specific to diamond)Sedimentary Geology, Vol. 393-394, pdfGlobalhyperspectral

Abstract: The study of sediment cores allows for the reconstruction of past climate and environment through physical-chemical analysis. Nevertheless, this interpretation suffers from many drawbacks that can be overcome with the newest technologies. Hyperspectral imaging is one of these and allows a fast, high resolution, and non-destructive analysis of sediment cores. In this study, we use visible and near-infrared hyperspectral imaging to predict particle size fractions and distribution (PSD) at a resolution of 200?µm on a previously well-studied sediment core taken from Lake Bourget (Western Alps, France). These predictions agree with previous studies on this core. Then, the PSD was used to estimate sedimentary deposit sources using the PSD unmixing algorithm AnalySize. It permitted estimation of the contribution of five sources (micrite, small and large bio-induced calcite crystals, diatom frustules, detrital particles), which had previously been characterized. The spatial dimension allowed for laminae to be discretized and counted, in agreement with the age-depth model previously established. We then evaluated the particle size and spectral signatures of each of these annual laminae, hence characterizing their physico-chemical composition. These high-resolution data also allowed for estimation of the accumulation rate (cm/year) of each of the main sources in the laminated unit and inferring the trophic status and the presence of instantaneous events of the lake.
DS1996-1447
1996
Arnaud, N.Turner, S., Arnaud, N., Deng, W.Post collision shoshonitic volcanism on the Tibetan Plateau: Implications for convective thinning ...Journal of Petrology, Vol. 37, No. 1, Feb. 1, pp. 45-?China, MantleLithosphere, Ocean Island Basalts
DS2003-0396
2003
Arnaud, N.Faure, M., Lin, W., Scharer, U., Shu, L., Sun, Y., Arnaud, N.Continental subduction and exhumation of UHP rocks. Structural and geochronologicalLithos, Vol. 70, 3-4, pp. 213-41.ChinaUHP, geochronology
DS200412-0538
2003
Arnaud, N.Faure, M., Lin, W., Scharer, U., Shu, L., Sun, Y., Arnaud, N.Continental subduction and exhumation of UHP rocks. Structural and geochronological insights from the Dabie Shan, East China.Lithos, Vol. 70, 3-4, pp. 213-41.ChinaUHP, geochronology
DS201412-0671
2014
Arnaud, N.Pelleter, A-A., Caroff, M., Cordier, C., Bachelery, P., Nehlig, P., Debeuf, D., Arnaud, N.Melilite bearing lavas as Mayotte ( France): an insight into the mantle source below the Comores.Lithos, in press available 57p.Europe, FranceMelilite
DS201905-1021
2019
Arnaud, N.Chmyz, L., Arnaud, N., Biondo, J.C., Azzone, R.G., Bosch, D.Hf-Pb isotope and trace element constraints on the origin of the Jacupiranga Complex ( Brazil): insights into carbonatite genesis and multi-stage metasomatism of the lithospheric mantle.Gondwana Research, Vol. 71, pp. 16-27.South America, Brazilcarbonatite

Abstract: The Lower Cretaceous Jacupiranga complex, in the central-southeastern portion of the South American Platform, includes carbonatites in close association with silicate rocks (i.e. strongly and mildly silica-undersaturated series). Here we document the first hafnium isotope data on the Jacupiranga complex, together with new trace element and Pb isotope compositions. Even though liquid immiscibility from a carbonated silicate melt has been proposed for the genesis of several Brazilian carbonatites, isotopic and geochemical (e.g., Ba/La ratios, lack of pronounced Zr-Hf and Nb-Ta decoupling) information argues against a petrogenetic relationship between Jacupiranga carbonatites and their associated silicate rocks. Thus, an origin by direct partial melting of the mantle is considered. The isotopic compositions of the investigated silicate samples are coherent with a heterogeneously enriched subcontinental lithospheric mantle (SCLM) source of rather complex evolution. At least two metasomatic processes are constrained: (1) a first enrichment event, presumably derived from slab-related fluids introduced into the SCLM during Neoproterozoic times, as indicated by consistently old TDM ages and lamprophyre trace signatures, and (2) a Mesozoic carbonatite metasomatism episode of sub-lithospheric origin, as suggested by eNd-eHf values inside the width of the terrestrial array. The Jacupiranga parental magmas might thus derive by partial melting of distinct generations of metasomatic vein assemblages that were hybridized with garnet peridotite wall-rocks.
DS201908-1774
2019
Arnaud, N.Chmyz, L., Arnaud, N., Biondi, J.C., Azzone, R.G., Bosch, D.Hf-Pb isotope and trace element constraints on the origin of the Jacupiringa complex ( Brazil): insights into carbonatite genesis and multi-stage metasomatism of the lithospheric mantle.Gondwana Research, Vol. 71, pp. 16-27.South America, Brazilcarbonatite

Abstract: The Lower Cretaceous Jacupiranga complex, in the central-southeastern portion of the South American Platform, includes carbonatites in close association with silicate rocks (i.e. strongly and mildly silica-undersaturated series). Here we document the first hafnium isotope data on the Jacupiranga complex, together with new trace element and Pb isotope compositions. Even though liquid immiscibility from a carbonated silicate melt has been proposed for the genesis of several Brazilian carbonatites, isotopic and geochemical (e.g., Ba/La ratios, lack of pronounced Zr-Hf and Nb-Ta decoupling) information argues against a petrogenetic relationship between Jacupiranga carbonatites and their associated silicate rocks. Thus, an origin by direct partial melting of the mantle is considered. The isotopic compositions of the investigated silicate samples are coherent with a heterogeneously enriched subcontinental lithospheric mantle (SCLM) source of rather complex evolution. At least two metasomatic processes are constrained: (1) a first enrichment event, presumably derived from slab-related fluids introduced into the SCLM during Neoproterozoic times, as indicated by consistently old TDM ages and lamprophyre trace signatures, and (2) a Mesozoic carbonatite metasomatism episode of sub-lithospheric origin, as suggested by eNd-eHf values inside the width of the terrestrial array. The Jacupiranga parental magmas might thus derive by partial melting of distinct generations of metasomatic vein assemblages that were hybridized with garnet peridotite wall-rocks.
DS200912-0772
2009
Arnaud, N.C.Travassos da Rosa Costa, L., Monie, P., Lafon, J-M., Arnaud, N.C.40 Ar 39 Ar geochronology across Archean and Paleoproterozoic terranes from southeastern Guiana Shield: evidence for contrasting cooling histories.Journal of South American Earth Sciences, Vol. 27, 2-3, pp. 113-128.South America, BrazilGeochronology
DS1989-0037
1989
Arnaud Gerkens, J.C.Arnaud Gerkens, J.C.Foundations of exploration geophysicsElsevier, 688p. $ 205.00BookGeophysics, Seismics/gravity/magnetics/electromagnetic/Radioactive
DS1995-0060
1995
Arndt, N.Arndt, N., Lehert, K., Vasilev, Y.Meimechites: highly magnesian lithosphere contaminated alkaline magmas from deep subcontinental mantle.Lithos, Vol. 34, No. 1-3, Jan. pp. 41-60.MantleMeimechites, Alkaline rocks
DS1995-1044
1995
Arndt, N.Lahaye, Y., Arndt, N., Gruau, G.The influence of alteration on the trace element and neodymium isotopic compositions of komatiitesChemical Geology, Vol. 126, No. 1, Nov. 20, pp. 43-64AustraliaKomatiites, Alteration, Metasomatism
DS1996-1183
1996
Arndt, N.Richard, D., Marty, B., Chaussidon, M., Arndt, N.Helium isotope evidence for a lower mantle component in depleted ArcheankomatiiteScience, Vol. 273, July 5, pp. 93-94Mantle, Ocean Island BasaltsKomatiite, Geochronology
DS1996-1184
1996
Arndt, N.Richard, D., Marty, B., Chaussidon, M., Arndt, N.Helium isotopic evidence for a lower mantle component in depleted ArcheankomatiiteScience, Vol. 273, July 5, pp. 93-95OntarioKomatiites, Deposit -Alexo
DS1998-0047
1998
Arndt, N.Arndt, N., Ginibre, C., Chauvel, Albaraede, CheadleWere komatiites wet?Geology, Vol. 26, No. 8, Aug. pp. 739-42GlobalMelting hydrous mantle, spiniflex textures, Magmatic volatiles
DS1999-0111
1999
Arndt, N.Capdevila, R., Arndt, N., Sauvage, J.F.Diamonds in volcaniclastic komatiite from French GuianaNature., Vol. 399, No. 6735, June 3, pp. 456-8.French GuianaKomatiite
DS2001-0048
2001
Arndt, N.Arndt, N.Hot heads and cold tails... volumes of lavaNature, Vol. 407, Sept. 28, pp. 458-61.MantlePlumes, hotspots
DS2001-0049
2001
Arndt, N.Arndt, N., Bruzak, G., Reischmann, T.The oldest continental and oceanic plateaus: geochemistry of basalts and komatiites Pilbara CratonGeological Society of America Special Paper, Special Paper. 352, pp. 359-88.AustraliaBasalts, Craton
DS2002-0680
2002
Arndt, N.Hauri, E.H., Kent, A.J., Arndt, N.Melt inclusions at the milennium: toward a deeper understanding of magmatic processes.Chemical Geology, Vol.183, 1-4, pp. 1-3.MantleMagmatism
DS2003-0034
2003
Arndt, N.Arndt, N.Komatiites, kimberlites and boninitesJournal of Geophysical Research, Vol. 108, 6, 10.1029/2002JB002157GlobalReview
DS2003-0035
2003
Arndt, N.Arndt, N.Komatiites, kimberlites and boninitesJournal of Geophysical Research, Vol. 108, B6, 10.1029/2002JB002157 June 6MantleKimberlites - related rocks
DS2003-1099
2003
Arndt, N.Poupinet, G., Arndt, N., Vacher, P.Seismic tomography beneath stable tectonic regions and the origin and composition ofEarth and Planetary Science Letters, Vol. 212, 1-2, pp. 89-101.MantleTectonics
DS200412-0054
2003
Arndt, N.Arndt, N.Komatiites, kimberlites and boninites.Journal of Geophysical Research, Vol. 108, B6, 10.1029/2002 JB002157 June 6MantleKimberlites - related rocks
DS200412-1574
2003
Arndt, N.Poupinet, G., Arndt, N., Vacher, P.Seismic tomography beneath stable tectonic regions and the origin and composition of the continental lithospheric mantle.Earth and Planetary Science Letters, Vol. 212, 1-2, pp. 89-101.MantleGeophysics - seismics Tectonics
DS200612-1517
2005
Arndt, N.Weihed, P., Arndt, N., Billstrom, K., Duschesne, J-C., Eilu, P., Martinsson, O., Papunen, H., Lahtinen, R.Precambrian geodynamics and ore formation: the Fennoscandian shield.Ore Geology Reviews, Vol. 27, pp. 273-322.Europe, FennoscandiaMetallogeny - tectonics
DS201212-0026
2012
Arndt, N.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
DS201312-0027
2013
Arndt, N.Arndt, N.How kimberlites form: clues from olivine geochemistry.Goldschmidt 2013, AbstractMantleGenesis
DS201412-0016
2014
Arndt, N.Arndt, N.Olivine in kimberlites: lithospheric versus shallow processes.ima2014.co.za, AbstractMantleOlivine
DS201412-0140
2015
Arndt, N.Condie, K.C., Davaille, A., Aster, R.C., Arndt, N.Upstairs-downstairs: supercontinents amd large igneous provinces, are they related?International Geology Review, Vol. 57, 11-12, pp. 1341-1348.GlobalSupercontinents
DS201412-0145
2014
Arndt, N.Cordier, C., Sauzert, L., Arndt, N., Boullier, A-M.Olivine in kimberlites: metasomatism of the deep lithospheric mantle.Economic Geology Research Institute 2014, No. 11390 1p. abstractMantleMetasomatism
DS201412-0805
2014
Arndt, N.Shervais, J.W., Arndt, N., Goodenough, K.M.Drilling the solid earth: global geodynamic cycles and earth evolution.International Journal of Earth Sciences, Vol. 104, 6, pp. 1573-1587.MantleGeodynamics - tectonics
DS201607-1381
2016
Arndt, N.Tappe, S., Griffin, W., Janney, P., Arndt, N., Gurney, J.The dynamic Earth and its kimberlite, cratonic mantle and diamond record through time.IGC 35th., Session A Dynamic Earth 1p. AbstractMantleKimberlite
DS201707-1316
2017
Arndt, N.Condie, K., Arndt, N., Davaille, A., Puetz, S.J.Zircon age peaks: production or preservation of continental crust?Geosphere, Vol. 10, 6, pp. 397-398.Mantlegeochronology

Abstract: Zircon age peaks are commonly interpreted either as crustal production peaks or as selective preservation peaks of subduction-produced crust selectively preserved during continent-continent collision. We contribute to this ongoing debate, using the Nd isotopic compositions of felsic igneous rocks and their distribution during the accretionary and collisional phases of orogens. The proportion of juvenile input into the continental crust is estimated with a mixing model using arc-like mantle and reworked continental crust end members. Orogen length and duration proxies for juvenile crustal volume show that the amount of juvenile crust produced and preserved at zircon age peaks during the accretionary phase of orogens is =3 times that preserved during the collisional phase of orogens. The fact that most juvenile crust is both produced and preserved during the accretionary phase of orogens does not require craton collisions for its preservation, thus favoring the interpretation of zircon age peaks as crustal production peaks. Most juvenile continental crust older than 600 Ma is produced and preserved before final supercontinent assembly and does not require supercontinent assembly for its preservation. Episodic destabilization of a compositionally heterogeneous layer at the base of the mantle may produce mantle plume events leading to enhanced subduction and crustal production. Our Nd isotope model for cumulative continental growth based on juvenile crust proxies for the past 2.5 b.y. suggests a step-like growth curve with rapid growth in accretionary orogens at the times of zircon age peaks.
DS201708-1594
2017
Arndt, N.Arndt, N.Formation of dunite xenoliths in kimberlites and allikites, petrographic and mineral compositions from a deformed xenolith in the Majuagaa kimberlite dike, Greenland.11th. International Kimberlite Conference, PosterEurope, Greenlanddeposit - Majuagaa
DS201809-1990
2018
Arndt, N.Arndt, N., Roman, A.Numerical modelling reveals weaknesses in the sagduction model for the formation of Archean continental crust: relevance to the onset of plate tectonics.Goldschmidt Conference, 1p. AbstractMantleplate tectonics

Abstract: Recent studies conclude that plate tectonics started 3 b.y. ago in the mid Archean. A transition from a "presubduction" regime to modern plate tectonics is said to be marked by changes in trace-element or isotopic ratios, the appearance of eclogitic inclusions in diamonds, or an apparent change in upper crust composition. Behind these arguments is the notion that subduction was intermittent or impossible early in Earth history when the mantle was hotter. If so, a mechanism other than subduction must have created granitoids of Archean continental crust. In the sagduction model, the base of thick oceanic crust converts to eclogite, founders, and melts to generate granitic magma. Here we evaluate two crucial constraints on the sagduction process: to generate granitic magma requires that water and basalt is taken deep into the mantle; thick oceanic crust is internally differentiated into uppermost layers of hydrated basalt and lower mafic-ultramafic cumulates. Our numerical modelling shows that any deformation within thick, differentiated crust is restricted to the lower cumulates that lack ingredients essential to generate granitic magma. Emplacement of hot intrusions heats the lower crust which was hot and anhydrous. We conclude that the sagduction model is flawed. Recent re-evaluation gives temperatures in ambient Archean upper mantle only moderately higher than in modern mantle, which deflates arguments that subduction was impossible in the Archean. We conclude that Archean continental crust was generated in subduction zones and that plate tectonics started in the early Archean.
DS201907-1576
2019
Arndt, N.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).
DS201911-2557
2019
Arndt, N.Roman, A., Arndt, N.Differentiated Archean oceanic crust: its thermal structure, mechanical stability and a test of the sagduction hypothesis.Geochimica et Cosmochimica Acta, in press available. 13p.Mantleplate tectonics

Abstract: Many recent studies conclude that plate tectonics started about 3 billion years ago in the mid Archean. The transition from a pre-subduction regime to modern plate tectonics is reported to be marked by changes in trace element ratios or isotopic compositions that monitor the rate of growth of the continental crust, the appearance of eclogitic inclusions in diamonds, or an apparent change in the composition of the upper crust. Behind most of these arguments is the hypothesis that, early in Earth history when the mantle was hotter, subduction was intermittent or impossible. If so, a mechanism other than subduction must have created the granitoids that dominate Archean continental crust. One alternative, commonly referred to as sagduction, proposes that the base of thick oceanic crust founders and partially melts to generate granitic magma. Here we evaluate the sagduction process, starting by discussing two crucial concepts: (1) thick oceanic crust is internally differentiated, with hydrated basalt being restricted to the uppermost layers, (2) the generation of granitic magma requires that water and basalt is present in the lower part of the crust or is taken deep into the mantle. We present the results of numerical modelling that demonstrates that when intrusion is taken into account, the lower portion of the crust is well above dehydration temperatures and therefore essentially dry. We show that any deformation within thick, differentiated crust is restricted to the lowermost layers of dry, infertile mafic-ultramafic cumulates that lack the ingredients essential for the generation of granitic magma. Given the implausibility of the sagduction process, we suggest that subduction was the main mechanism that generated granitoid magmas, in the Archean as today.
DS1997-0449
1997
Arndt, N.A.Griselen, M., Arndt, N.A., Baragar, W.R.A.Plume lithosphere interaction and crustal contamination during formation of Coppermine River basalts, northwest Territories.Canadian Journal of Earth Sciences, Vol. 34, No. 7, July pp. 958=975Northwest TerritoriesMantle plumes, Mackenzie dyke swarms, geochronology, Coppermine River basalts
DS1975-0454
1977
Arndt, N.T.Arndt, N.T.Ultrabasic Magmas and High Degree Melting of the MantleContributions to Mineralogy and Petrology, Vol. 64, pp. 205-21.MantleMelting, Peridotite
DS1989-0038
1989
Arndt, N.T.Arndt, N.T., Goldstein, S.L.An open boundary between lower continental crust andmantle: its role incrust formation and crustalrecyclingTectonophysics, Vol. 161, No. 3/4, pp. 201-212GlobalMantle, Tectonic regimes
DS1990-0433
1990
Arndt, N.T.Dupre, B., Arndt, N.T.lead isotopic compositions of Archean komatiites and sulfidesChemical Geology, Vol. 85, No. 1/2, July 10 pp. 35-56AustraliaKambalda, Komatiites
DS1991-0034
1991
Arndt, N.T.Arndt, N.T.High nickel in Archean tholeiitesTectonophysics, Vol. 187, pp. 411-419Australia, Greenland, Abitibi, FinlandNickel, Tholeiites
DS1991-0035
1991
Arndt, N.T.Arndt, N.T., Nelson, D.R., Compston, W., Trendall, A.F.The age of the Fortescue Group, Hammersley Basin, Western Australia, from ion microprobe zircon uranium-lead (U-Pb) (U-Pb) resultsAustralian Journal of Earth Sciences, Vol. 38, pp. 261-281AustraliaGeochronology, Pilbara craton
DS1992-0044
1992
Arndt, N.T.Arndt, N.T., Lesher, C.M.Fractionation of rare earth elements (REE)'s by olivine and the origin of Kambalda western AustraliaGeochimica et Cosmochimica Acta, Vol. 56, pp. 4191-4204AustraliaGeochemistry, Komatiites
DS1992-0138
1992
Arndt, N.T.Boher, M., Abouchami, W., Michard, A., Albarede, F., Arndt, N.T.Crustal growth in West Africa at 2.1 GaJournal of Geophysical Research, Vol. 97, No. B1, January 10, pp. 345-369GlobalGeophysics, Craton
DS1993-1136
1993
Arndt, N.T.Nisbet, .G., Cheadle, M.J., Arndt, N.T., Bickle, M.J.Constraining the potential temperature of the Archean mantle: a review Of the evidence from komatiitesLithos, Vol. 30, No. 3-4, September pp. 291-308MantleKomatiites, Thermometry
DS1993-1760
1993
Arndt, N.T.Wooden, J.L., Czamanske, G.K., Fedorenko, V.A., Arndt, N.T., Chauvel, C.Isotopic and trace element constraints on mantle and crustal contributions to Siberian continental flood basalts, Noril'sk area, SiberiaGeochimica et Cosmochimica Acta, Vol. 57, pp. 3677-3704Russia, SiberiaGeochronology, Basalts, Noril'sk
DS1996-0138
1996
Arndt, N.T.Bleichert-Toft, J., Arndt, N.T., Ludden, J.N.Precambrian alkaline magmatismLithos, Vol. 37, No. 2-3, April 1, pp. 97-112.GlobalMagmatism -alkaline
DS1996-0140
1996
Arndt, N.T.Blichert-Toft, J., Arndt, N.T., Ludden, J.N.Precambrian alkaline magmatismLithos, Vol. 37, No. 2/3, April pp. 97-112GlobalMagmatism, Alkaline rocks
DS1997-0042
1997
Arndt, N.T.Arndt, N.T., Kerr, A.C., Tarney, J.Dynamic melting in plume heads; the formation of Gorgona komatiitebasaltsEarth and Planetary Science Letters, Vol. 146, No. 1-2, Jan. 1, pp. 289-302GlobalMantle plumes, Komatiites
DS1998-1195
1998
Arndt, N.T.Puchtel, I.S., Arndt, N.T., Nemchin, A.A.Petrology of mafic lavas within the Onega Plateau, central Karelia:evidence for 2.0 Ga plume related ...Contributions to Mineralogy and Petrology, Vol. 130, No. 2, pp. 134-153.Russia, Karelia, Baltic shieldContinental crustal growth
DS2001-0587
2001
Arndt, N.T.Kerr, A.C., Arndt, N.T.A note on the IUGS reclassification of the high Mg and picritic volcanic rocksJournal of Petrology, Vol. 42,No. 11, pp. 2169-71.GlobalClassification - picrites
DS2001-0588
2001
Arndt, N.T.Kerr, A.C., Arndt, N.T.A note on the IUGS reclassification of the high magnesium and picritic volcanic rocksJour. Petrol., Vol. 42, No. 11, pp. 2169-72.GlobalPicrites - classification, Petrology
DS2002-0064
2002
Arndt, N.T.Arndt, N.T., Lewin, E., Albaredem, F.Strange partners: formation and survival of continental crust and lithospheric mantleGeological Society of London Special Publication, No. 199, pp. 91-104.MantleTectonics
DS200412-0164
2004
Arndt, N.T.Blichert-Toft, J., Arndt, N.T., Gruau, G.Hf isotopic measurements on Barberton komatiites: effects of incomplete sample dissolution and importance for primary and secondChemical Geology, Vol. 207, 3-4, July 16, pp. 261-275.Africa, South AfricaGeochronology - not specific to diamonds
DS200412-0231
2004
Arndt, N.T.Bruneton, M., Pedersen, H.A., Vacher, P., Kukkonenen, I.T., Arndt, N.T., Funke, S., Friederich, W., Farra, V.Layered lithospheric mantle in the central Baltic Shield from surface waves and xenolith analysis.Earth and Planetary Science Letters, Vol. 226, 1-2, pp. 41-52.Baltic Shield, Norway, Finland, RussiaGeophysics - seismics, xenoliths
DS200512-0028
2005
Arndt, N.T.Arndt, N.T., Herzberg, C.The temperature of mantle plumes.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractUnited States, HawaiiMantle plume, geothermometry
DS200612-0118
2006
Arndt, N.T.Ben Othman, D., Luck, J.M., Bodinier, J.L., Arndt, N.T., Albarede, F.Cu Zn isotopic variations in the Earth's mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleGeochemistry
DS200612-0954
2006
Arndt, N.T.Mungall, J.E., Hanley, J.J., Arndt, N.T., Debecdelievre, A.Evidence from meimechites and other low degree mantle melts for redox controls on mantle crust fractionation of platinum group elements.Proceedings of National Academy of Science USA, Vol. 103, 34, pp. 12695-12700.MantleMeimechite, PGE
DS200812-0046
2008
Arndt, N.T.Arndt, N.T., Coltice, N., Helstaedt, H., Gregoire, M.Origin of Archean subcontinental lithospheric mantle: some petrological constraints.Lithos, In press available 47p.CanadaArchean - craton
DS200812-0206
2008
Arndt, N.T.Chauvel, C., Lewin, E., Carpenier, M., Arndt, N.T., Marini, J.C.Role of recycled oceanic basalt and sediment in generating the Hf Nd mantle array.Nature Geoscience, Vol. 1, 1, pp. 64-67.MantleGeochemistry
DS200912-0013
2009
Arndt, N.T.Arndt, N.T., Coltice, N., Helmstaedt, H., Gregorie, M.Origin of Archean subcontinental lithospheric mantle: some petrological constraints.Lithos, Vol. 109, 1-2, pp. 61-71.MantlePetrology
DS201012-0012
2010
Arndt, N.T.Arndt, N.T., Guitreau, M., Boullier, A-M., Le Roex, A., Tommasi, A.M., Cordier, P., Sobolev, A.Olivine, and the origin of kimberlite.Journal of Petrology, Vol. 51, 3, pp. 573-602.TechnologyKimberlite genesis
DS201112-0173
2011
Arndt, N.T.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
DS201312-0780
2013
Arndt, N.T.Sauzeat, L., Cordier, C., Arndt, N.T.How kimberlites form: clues from olivine geochemistry.Goldschmidt 2013, 1p. AbstractTechnologyKimberlite genesis
DS201412-0017
2013
Arndt, N.T.Arndt, N.T.Formation and evolution of the continental crust.Geochemical Perspectives Letters, Vol. 2, 3, pp. 405-533.MantleGeodynamics
DS201512-1905
2015
Arndt, N.T.Cordier, C., Sauzeat, L., Arndt, N.T., Boullier, A-M., Batanova, V., Barou, F.Metasomatism of the lithospheric mantle immediately precedes kimberlite eruption: new evidence from olivine composition and microstructures.Journal of Petrology, Vol. 56, 9, pp. 1775-1796.TechnologyOlivine, metasomatism

Abstract: Most kimberlites contain abundant dunitic nodules. These are centimetre-sized, rounded and multi-grained assemblages of xenocrystic olivine with a wide range of compositions (Fo83 to Fo94). The absence of orthopyroxene and other mantle minerals and the range of olivine compositions have been attributed to reaction between mantle peridotite and (proto)kimberlitic fluid or melt, but the timing of the reaction is a subject of debate. In a kimberlite from the Kangamiut region of Greenland, nodule cores are surrounded by fine-grained outer margins with near-constant Fo contents (~Fo88) but highly variable minor element contents (e.g. 500-2500 ppm Ni). These margins crystallized from the kimberlite melt and we show that their compositions can be explained by crystallization of olivine alone, if a high partition coefficient for Ni between melt and olivine (DNi > 20) is assumed. Orthopyroxene assimilation is not required, removing the constraint that its dissolution occurred during ascent of the kimberlite magma. Within some nodules, in addition to the usual core-to-margin gradients, we observe asymmetric compositional changes (variable Fo but near-constant minor element contents) across mobile grain boundaries. These changes document fluid percolation at the grain scale that occurred during dynamic recrystallization in the deforming lithospheric mantle. We note that chemical gradients associated with mobile grain boundaries are observed in olivines that cover the entire compositional range of the nodules, and propose that fluid-assisted dynamic recrystallization took place in dunite that was already compositionally heterogeneous. Reaction between peridotite and protokimberlitic melt or fluid and dissolution of orthopyroxene thus occurred within the lithospheric mantle, immediately (a few days) prior to the ascent of the kimberlite melt and the entrainment of the dunite nodules. We propose that the grain boundary zones probably mimic, at a fine scale, the fluid-peridotite interaction that caused, at a larger scale, orthopyroxene dissolution and formation of compositionally diverse olivine in kimberlites.
DS201601-0011
2015
Arndt, N.T.Cordier, C., Sauzeat, L., Arndt, N.T., Boullier, A-M., Batanova, V., Barou, F.Metasomatism of the lithospheric mantle immediately precedes kimberlite eruption: new evidence from olivine composition and mircostructures.Journal of Petrology, Vol. 56, 9, pp. 1775-1796.Europe, GreenlandDeposit - Kangamiut field

Abstract: Most kimberlites contain abundant dunitic nodules. These are centimetre-sized, rounded and multi-grained assemblages of xenocrystic olivine with a wide range of compositions (Fo83 to Fo94). The absence of orthopyroxene and other mantle minerals and the range of olivine compositions have been attributed to reaction between mantle peridotite and (proto)kimberlitic fluid or melt, but the timing of the reaction is a subject of debate. In a kimberlite from the Kangamiut region of Greenland, nodule cores are surrounded by fine-grained outer margins with near-constant Fo contents (~Fo88) but highly variable minor element contents (e.g. 500-2500 ppm Ni). These margins crystallized from the kimberlite melt and we show that their compositions can be explained by crystallization of olivine alone, if a high partition coefficient for Ni between melt and olivine (DNi > 20) is assumed. Orthopyroxene assimilation is not required, removing the constraint that its dissolution occurred during ascent of the kimberlite magma. Within some nodules, in addition to the usual core-to-margin gradients, we observe asymmetric compositional changes (variable Fo but near-constant minor element contents) across mobile grain boundaries. These changes document fluid percolation at the grain scale that occurred during dynamic recrystallization in the deforming lithospheric mantle. We note that chemical gradients associated with mobile grain boundaries are observed in olivines that cover the entire compositional range of the nodules, and propose that fluid-assisted dynamic recrystallization took place in dunite that was already compositionally heterogeneous. Reaction between peridotite and protokimberlitic melt or fluid and dissolution of orthopyroxene thus occurred within the lithospheric mantle, immediately (a few days) prior to the ascent of the kimberlite melt and the entrainment of the dunite nodules. We propose that the grain boundary zones probably mimic, at a fine scale, the fluid-peridotite interaction that caused, at a larger scale, orthopyroxene dissolution and formation of compositionally diverse olivine in kimberlites.
DS201605-0903
2016
Arndt, N.T.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.
DS201706-1068
2017
Arndt, N.T.Cordier, C., Sauzeat, L., Arndt, N.T., Boullier, A-M., Batanova, V., Barou, F.Quantitative modelling of the apparent decoupling of Mg# and Ni in kimberlitic olivine margins: comment on Cordier et al. by A.Moore.Journal of Petrology, Vol. 58, pp. 1-3.Europe, Greenlanddeposit - Kangamiut

Abstract: Moore proposes in his Comment (Moore, 2017) that marginal zones in olivine grains in kimberlites (Fig. 1a) are produced by crystallization from kimberlite melt. He suggests that the chemical zones observed in these marginal zones (inner transition zones and outer margins, illustrated in his fig. 1) result from abrupt changes in distribution coefficients during crystallization. He proposes that the transition zones, characterized by variable Fo at constant and high Ni contents, are produced by crystallization with high KdFe-Mg (= 0•45) and low DNi (= 4) whereas the margins, characterized by a sharp drop in Ni content at nearly constant Fo (Fig. 1b), are produced by crystallization with higher DNi owing to a sudden change in physical conditions of crystallization (P,…
DS201712-2674
2017
Arndt, N.T.Arndt, N.T., Fontbote, L., Hedenquist, J.W., Kesler, S.E., Thompson, J. F.H., Wood, D.G.Future Global and Mineral Resources.geochemicalperspectives.org, Vol. 6, 1, April, 187p. Pdf 28 MBGlobalgeochemistry

Abstract: Some scientists and journalists, and many members of the general public, have been led to believe that the world is rapidly running out of the metals on which our modern society is based. Advocates of the peak metal concept have predicted for many decades that increasing consumption will soon lead to exhaustion of mineral resources. Yet, despite ever-increasing production and consumption, supplies of minerals have continued to meet the needs of industry and society, and lifetimes of reserves remain similar to what they were 30-40 years ago. In this volume, we discuss the reasons for this apparent paradox using our broad experience and expertise on both academic and industrial sides of the minerals sector. Many misconceptions arise from flawed estimates of the size of global mineral resources which stem from a lack of understanding of the critical difference between reserves and resources. Some authors use quoted reserves – the amount of metal proven to exist and to be economic for mining at present – when predicting imminent shortages. Resources – the amount that may be accessible in the upper few kilometres of the crust – are far larger.Over the last 150 years, improved technologies, economies of scale and increased efficiency have combined to reduce costs hence allowing lower-grade ore to be mined economically. The net result is that the long-term inflation-adjusted price of most metals has decreased more or less in parallel with increasing production, a second apparent paradox that frequently is not well understood. Using copper as the principal example and other metals as appropriate, we summarise the latest research on ore deposits and the activities of the minerals industry. Following a description of the numerous geological processes that form ore deposits, we outline the scientific methods used by the minerals industry to explore for new deposits. We also discuss how resources are mined and how minerals are processed, as well as recent efforts to reduce related environmental impacts. Economic and societal factors influence supply, and these are as important as the actual presence of a resource. Finally, we discuss the critical roles that geoscientists will play in assuring continued supplies of minerals. These include the development of new concepts and techniques that will assist the discovery, mining, processing, remediation, and management of mineral resources. It is essential that researchers help to educate the general public about the need for continued exploration to find new resources to meet growth in world living standards. We demonstrate that global resources of copper, and probably of most other metals, are much larger than most currently available estimates, especially if increasing efficiencies and higher prices allow lower-grade ores to be mined. These observations indicate that supplies of important mineral commodities will remain adequate for the foreseeable future.
DS201805-0944
2018
Arndt, N.T.Eeken, T., Goes, S., Pedersen, H.A., Arndt, N.T., Bouilhol, P.Seismic evidence for depth dependent metasomatism in cratons.Earth Planetary Science Letters, Vol. 491, pp. 148-159.Africa, Australia, Canada, Europegeothermometry

Abstract: The long-term stability of cratons has been attributed to low temperatures and depletion in iron and water, which decrease density and increase viscosity. However, steady-state thermal models based on heat flow and xenolith constraints systematically overpredict the seismic velocity-depth gradients in cratonic lithospheric mantle. Here we invert for the 1-D thermal structure and a depth distribution of metasomatic minerals that fit average Rayleigh-wave dispersion curves for the Archean Kaapvaal, Yilgarn and Slave cratons and the Proterozoic Baltic Shield below Finland. To match the seismic profiles, we need a significant amount of hydrous and/or carbonate minerals in the shallow lithospheric mantle, starting between the Moho and 70 km depth and extending down to at least 100-150 km. The metasomatic component can consist of 0.5-1 wt% water bound in amphibole, antigorite and chlorite, ~0.2 wt% water plus potassium to form phlogopite, or ~5 wt% CO2 plus Ca for carbonate, or a combination of these. Lithospheric temperatures that fit the seismic data are consistent with heat flow constraints, but most are lower than those inferred from xenolith geothermobarometry. The dispersion data require differences in Moho heat flux between individual cratons, and sublithospheric mantle temperatures that are 100-200?°C less beneath Yilgarn, Slave and Finland than beneath Kaapvaal. Significant upward-increasing metasomatism by water and CO2-rich fluids is not only a plausible mechanism to explain the average seismic structure of cratonic lithosphere but such metasomatism may also lead to the formation of mid-lithospheric discontinuities and would contribute to the positive chemical buoyancy of cratonic roots.
DS201901-0005
2018
Arndt, N.T.Aulbach, S., Arndt, N.T.Ecologites as paleodynamic archives: evidence for warm ( not hot) and depleted ( but heterogeneous) Archean ambient mantle.Earth and Planetary Science Letters, Vol. 505, pp. 162-172.Mantleeclogites

Abstract: Some high-Mg eclogite xenoliths, entrained by kimberlites from the mantle lithospheres of ancient continental cores, and rare orogenic eclogites and ophiolites, exhumed or obducted during the closure of palaeo-ocean basins, have elemental and isotopic compositions indicative of protoliths that formed as little-differentiated melts erupted in ancient ocean floors. Despite metamorphism and, in part, partial melt loss, these samples of ancient mid-ocean ridge basalt and picrite retain a memory of the chemical and physical state of their protoliths' ambient convecting mantle sources. Published data show that, when filtered to exclude specimens with cumulate protoliths or showing evidence for later enrichment (metasomatism), the samples lack Y or Al 2 O 3 depletion relative to TiO 2 and MgO. This indicates melt segregation of the protolith predominantly from a garnet-free peridotite source and implies intersection of the solidus at low pressures (=3 GPa). Given the dependence of melt composition and volume on source composition (assumed to be similar to modern depleted mantle) and mantle potential temperature (T P), we calculate moderate average melt fractions F (~0.22 ± 0.01) from the Ti contents of the least differentiated samples in three sample suites with 2.6 to 2.9 Ga ages. This converts to T P of ~1410 ± 10 • C assuming a final pressure of melting of 0.5 GPa, melt productivity of 10%/GPa and mantle adiabat of 0.4 • C/km, and using a mantle solidus parameterisation. Though model-dependent, the results are in agreement with recent work advocating moderate Archaean mantle T P. Estimates drop to F = 0.19 and T P = 1380 • C at 1.9 Ga and F = 0.12 and T P = 1310 at 0.6 Ga, corresponding to a decrease in T P of only ~100 • C over the last 3 Ga. A less depleted mantle source yields higher F and T P , but the above estimates are in better agreement with qualitative evidence from Al 2 O 3 and Y, and with Nd-Hf and Sr isotope compositions of orogenic eclogite and granulite suites and mantle eclogites, respectively, which indicate that portions of the Meso-to Neoarchaean mantle were depleted. Moderate T P supports early plate strengthening and a possible transition to plate tectonics in the Mesoarchaean if not earlier. Moreover, moderate temperatures in Archaean subduction zones may have facilitated deep recycling of volatiles that would otherwise have been lost from subducting slabs at shallow depths.
DS1994-0707
1994
Arne, D.Hand, M., Scrimgeour, I., Stuwe, K., Arne, D., Wilson, C.J.Geological observations in high grade mid-Proterozoic rocks from ElsePlatform, Prince Charles Mtns. regionAustralian Journal of Earth Sciences, Vol. 41, pp. 311-329AntarcticaTectonics, Proterozoic
DS1998-0048
1998
Arne, D.C.Arne, D.C., Zentilli, M., Grist, A.M., Collins, M.Constraints on the timing of thrusting during the Eurekan Orogeny, Canadian Arctic Archipelago...Canadian Journal of Earth Sciences, Vol. 35, No. 1, Jan. pp. 30-38.Northwest Territories, Ellesmere Island, Sverdrup BasinGeochronology, geothermometry, Tectonics - thrust fault movements
DS2002-1682
2002
ArnoldWalters, S., Skrzecynski, B., Whiting, Bunting, ArnoldDiscovery and geology of the Cannington Ag Pb Zn deposit Mount Isa Eastern Succession: development ...Society of Economic Geologists Special Publication, No.9,pp.95-118.AustraliaSilver, lead, zinc, exploration model Broken Hill type, Deposit - Cannington
DS1999-0123
1999
Arnold, M.Chalot-Prat, F., Arnold, M.Immiscibility between calciocarbonatitic and silicate melts and related wall rock interactions upper mantleLithos, Vol. 49, No. 4, Apr. pp. 627-60.RomaniaMantle xenoliths, Carbonatite
DS1993-0043
1993
Arnold, R.Arnold, R., Gottlieb, A.Trashing the economy.. how runaway environmentalism is wrecking AmericaMerrill Press, 660p. $ 20.00United StatesBook -Table of contents, Environmental
DS1997-0043
1997
Arnold, R.H.Arnold, R.H.Interpretation of airphotos and remotely sensed imageryEarth Observation Magazine books, $ 40.00GlobalBook - ad, Remote sensing
DS1996-0044
1996
Arnold, T.D.Arnold, T.D.Underground mining: a challenge to establish open pit operationsSociety for Mining, Metallurgy and Exploration (SME)-American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, 96-37United StatesMining, Underground
DS1860-0242
1875
Arnot, D.Arnot, D., Orpen, F.H.S.The Land Question of Griqualand West: an Enquiry Into the Various Claims to Land in that Territory, with a Brief History of the Griqua Nation.Cape Town: Saul Solomon., 351P. XIII, 351P. MAPS.Africa, South AfricaHistory
DS1986-0408
1986
ArnottJohnson, B.D., Mayhewm M.A., O'Reilly, S.Y., Griffin, W.L., ArnottMagsat anomalies, crustal magnetisation, heat flow and kimberlite occurrences in AustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, Geological, No. 16, pp. 127-129AustraliaGeophysics, Magnetics
DS1985-0650
1985
Arnott, F.Sumpton, J., Arnott, F.A Specialized Application for Helicopter Airborne Magnetometer SystemFourth Int, Geophysical Conference and Exhibition, Held Sydney Australia, Exploration Geophysics, Vol. 16, No. 2-3, June-Sept. isAustraliaKimberlite, Geophysics
DS2000-0031
2000
Arnott, F.Arnott, F.3D analysis and mapping... computer technology .. brief overviewMin. Magazine, Vol. 183, No. 5, Nov. pp. 212-4.GlobalComputer - technology 3D.
DS2003-0036
2003
Arnott, F.Arnott, F., Kostlin, E.O.Petrophysics of kimberlites8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, AbstractGlobalDiamond exploration, Geophysics - petrology
DS200412-0055
2003
Arnott, F.Arnott, F., Kostlin, E.O.Petrophysics of kimberlites.8 IKC Program, Session 8, AbstractTechnologyDiamond exploration Geophysics - petrology
DS1982-0583
1982
Arnott, F.W.Stracke, K.J., Robinson, H.R., Arnott, F.W., Danchin, R.V., Sto.El 652 and El 853 Orroroo South Australia Progress Reports from 23rd. september 1981 to 19th. April 1982.South Australia Open File., No. E3891, 22P. UNPUBL.Australia, South AustraliaGeophysics, Geochemistry, Prospecting, Vlf, Stream Sediment Sampling
DS201812-2774
2018
Arnould, M.Arnould, M., Coltice, N., Flament, N., Seigneur, V., Muller, R.D.On the scales of dynamic topography in whole- mantle convection models.Geochemistry, Geophysics, Geosystems, Vol. 19, 9, pp. 3140-3163.United States, Californiasubduction

Abstract: Mantle convection shapes Earth's surface by generating dynamic topography. Observational constraints and regional convection models suggest that surface topography could be sensitive to mantle flow for wavelengths as short as 1,000 and 250 km, respectively. At these spatial scales, surface processes including sedimentation and relative sea-level change occur on million-year timescales. However, time-dependent global mantle flow models do not predict small-scale dynamic topography yet. Here we present 2-D spherical annulus numerical models of mantle convection with large radial and lateral viscosity contrasts. We first identify the range of Rayleigh number, internal heat production rate and yield stress for which models generate plate-like behavior, surface heat flow, surface velocities, and topography distribution comparable to Earth's. These models produce both whole-mantle convection and small-scale convection in the upper mantle, which results in small-scale (<500 km) to large-scale (>104 km) dynamic topography, with a spectral power for intermediate scales (500 to 104 km) comparable to estimates of present-day residual topography. Timescales of convection and the associated dynamic topography vary from five to several hundreds of millions of years. For a Rayleigh number of 107, we investigate how lithosphere yield stress variations (1050 MPa) and the presence of deep thermochemical heterogeneities favor small-scale (200500 km) and intermediate-scale (500104 km) dynamic topography by controlling the formation of small-scale convection and the number and distribution of subduction zones, respectively. The interplay between mantle convection and lithosphere dynamics generates a complex spatial and temporal pattern of dynamic topography consistent with constraints for Earth.
DS202009-1607
2020
Arnould, M.Arnould, M., Coltice, N., Flament, N., Mallard, C.Plate tectonics and mantle controls on plume dynamics.Earth and Planetary Science Letters, Vol. 547, 15p. PdfMantlegeodynamics

Abstract: Mantle plumes provide valuable information about whole-mantle convection: they originate at the core-mantle boundary, cross Earth's mantle and interact with the lithosphere. For instance, it has been proposed that the mobility/stability of plumes depends on plume intrinsic properties, on how slabs interact with the basal boundary layer, on mantle flow, or on their proximity to mid-ocean ridges. Here, we use 3D-spherical models of mantle convection generating self-consistent plate-like behaviour to investigate the mechanisms linking tectonics and mantle convection to plume dynamics. Our models produce fully-dynamic mantle plumes that rise vertically with deflection and present excess temperatures, rising speeds, buoyancy and heat fluxes comparable to observations. In the absence of plate tectonics, plumes are stable and their lifetime exceeds hundreds of million years. With plate tectonics, plumes are more mobile, and we identify four physical mechanisms controlling their stability. 1/ Fixed plumes are located at saddle points of basal mantle flow. 2/ Plumes moving at speeds between 0.5-1 cm yr-1 are slowly entrained by passive mantle flow. 3/ Fast plume motions between 2-5 cm yr-1 lasting several tens of million years are caused by slab push. 4/ Plumes occasionally drift at speeds >5 cm yr-1 over <10 Myr through plume merging. We do not observe systematic anchoring of plumes to mid-oceanic ridges. Independent of the presence of a dense basal layer, plate-like regimes decrease the lifetime of plumes compared to stagnant-lid models. Plume age, temperature excess or buoyancy flux are not diagnostic of plume lateral speed. The fraction of plumes moving by less than 0.5 cm yr-1 is >25%, which suggests that fixed hotspot reference frames can be defined from carefully selected hotspot tracks.
DS1985-0487
1985
Arnow, J.A.Nelson, K.D., Arnow, J.A., Mcbride, J.H., Wille, D.M., Brown, L.New Cocorp Profiling in the Southeastern U.s.: Major Features and Regional Implications.Geological Society of America (GSA), Vol. 17, No. 7, P. 675. (abstract.).United States, Appalachia, GeorgiaMidcontinent
DS1985-0732
1985
Arnow, J.A.Wille, D.M., Brown, L.D., Nelson, D.K., Arnow, J.A., Mcbride, J.The Surrency Bright Spot: Possible Evidence for Fluid in The Deep Crust.Geological Society of America (GSA), Vol. 17, No. 7, P. 751. (abstract.).United States, Appalachia, GeorgiaMidcontinent, Geotectonics, Suture Zone, Rift
DS2000-0032
2000
Arnst, N.Arnst, N.Geochemistry: hot heads and cold tailsNature, Vol. 407, No. 6803, Sept. 28, p. 458. 1p.MantlePlumes, hot spots
DS200612-0421
2006
Aronin, A.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
DS1998-0430
1998
Aronin, Tatsii et al.Fisenko, A.V., Semjonova, Aronin, Tatsii et al.Size separation of interstellar diamondsGeochemistry International, Vol. 36, No. 5, pp. 467-470.GlobalMeteor, Diamond homegeneity
DS1991-1040
1991
Aronson, D.E.Mallard, G.E., Aronson, D.E.United States Geological Survey (USGS) toxic substances hydrology program; abstracts of the technicalmeeting, Monterey California, March 11-15th. 1991United States Geological Survey (USGS) Open File, No. 91-088, 133pUnited StatesToxic substances
DS200412-1334
2004
Arora, K.Mishra, D.C., Arora, K., Tiwari, V.M.Gravity anomalies and associated tectonic features over the Indian Peninsular Shield and adjoining Ocean basins.Tectonophysics, Vol. 379, 1-4, Feb. 13, pp. 61-76.IndiaGeophysics - gravity, crust
DS201901-0093
2018
Arques, L.Xu, J., Melgarejo, C.M., Castillo-Oliver, M., Arques, L., Santamaria, J.Ilmenite generations in kimberlite from Banankoro, Guinea Conakry.Neues Jhabuch fur Mineralogie, Vol. 195, 3, pp. 191-204.Africa, Guineadeposit - Banankoro

Abstract: A complex mineral sequence in a kimberlite from the Banankoro Cluster (Guinea Conakry) has been interpreted as the result of magma mixing processes. The composition of the early generations of phlogopite and spinel suggest direct crystallisation of a kimberlitic magma. However, the compositional trends found in the late generations of phlogopite and spinels could suggest magma mixing. In this context, four ilmenite generations formed. The first generations (types 1 and 2) are geikielitic and are associated with spinel and phlogopite which follow the kimberlitic compositional trends. They are interpreted as produced by crystallization from the kimberlite magma. A third generation of euhedral tabular Mg-rich ilmenite (type 3) formed during the interval between two generations of serpentine. Finally, a late generation of Mn-rich ilmenite (type 4) replaces all the Ti-rich minerals and is contemporaneous with the last generation of serpophitic non-replacing serpentine. Therefore, the formation of type 3 and type 4 ilmenite took place after the crystallization of the groundmass, during late hydrothermal process. Our results suggest a detailed textural study is necessary when use Mg-rich and Mn-rich ilmenites as KIMs. © 2018 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany.
DS1996-0045
1996
Arregros, M.Arregros, M.Selected bibliography on diamonds in AfricaAfrica Geoscience Review, Vol. 3, No. 2, pp. 331-342.Africa, South Africa, Angola, Algeria, Botswana, Sierra LeoneBibliography, CAR, Congo, Ivory Coast, Ghana, Guinea, Liberia, Mali
DS200912-0795
2009
Arrial, P.A.Verhoeven, O., MacQuet, A., Vacher, P., Rivoldini, A., Menvielle, M., Arrial, P.A., Chiblet, G., Tarits,P.Constraints on thermal state and composition of the Earth's lower mantle from electromagnetic impedances and seismic data.Journal of Geophysical Research, Vol. 114, B3, B03302.MantleGeophysics - seismics
DS201112-0577
2011
Arribas, A.Lehbib, S., Arribas, A., Melgarejo, J.C., Martin, R.F.Rare element minerals of the alkaline suites of the western Sahara.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterAfricaAlkalic
DS201112-0578
2011
Arribas, A.Lehbib, S., Arribas, A., Melgarejo, J.C., Martin, R.F.Rare element minerals of the alkaline suites of the western Sahara.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.96-98.Africa, MauritaniaCarbonatite
DS201112-0579
2011
Arribas, A.Lehbib, S., Arribas, A., Melgarejo, J.C., Martin, R.F.Rare element minerals of the alkaline suites of the western Sahara.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.96-98.Africa, MauritaniaCarbonatite
DS200612-1572
2006
Arrowsmith, J.R.Yoburn, J.B., Fouch, M.J., Arrowsmith, J.R., Keller, G.R.A new GIS driven geophysical database for the southwestern United States.In: Sinha, A.K. Geoinformatics: data to knowledge, GSA Special Paper, 397, 397,pp.249-268.United StatesGeophysics - data
DS1997-0127
1997
Arseneau, L.P.Brewer, K.J., Bergevin, G., Arseneau, L.P.Lessons from Canadian mineral taxation: an international contextInternational Seminar on mining legislation, UN Econ. Europe, March 13-14, update June 57pCanadaEconomics, Exploration, mining, discoveries, legal
DS1986-0029
1986
Arseniev, T.A.Arseniev, T.A., Zilbertski, A.K., Sobolev, N.V.The estimation of pressure experiences by crystals of olivinefromkimberlites.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 286, No. 5, pp. 1220-1223RussiaPetrology
DS1986-0030
1986
Arsenyeva, T.A.Arsenyeva, T.A., Zilbershteyn, A.K., Sobolev, N.V.Evaluation of experimental pressure on olivine crystals inkimberlites.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR., (Russian), Vol. 286, No. 5, pp. 1220-1223RussiaExperimental Petrology
DS1987-0016
1987
Arsenyeva, T.A.Arsenyeva, T.A., Zilbershteyn, A.Kh., Sobolev, N.V.Determination of the hydrostatic pressure experienced at depth by olivine crystals from kimberliteDokl. Acad. Sciences USSR Earth Science Section, Vol. 286, No. 1-6, September pp. 143-146RussiaBlank
DS1960-0214
1962
Arsenyey, A.A.Arsenyey, A.A.The Laws of Distribution of Kimberlites in the Eastern Partof the Siberian PlatformDoklady Academy of Science USSR, Earth Science Section., Vol. 137, PP. 355-357.RussiaBlank
DS1860-0537
1887
Art JournalArt JournalNorth Carolina Wealth in Precious Minerals and MetalsArt Journal, Nov. P.United States, North Carolina, AppalachiaDiamond Occurrence
DS200812-0047
2008
Artamonov, A.V.Artamonov, A.V., Zolotarev, B.P.Tectonics and magmatism of intraplate oceanic rises and the hot spot hypothesis.Geotectonics, Vol. 42, 1, pp. 64-79.MantleMagmatism
DS1986-0198
1986
Artamonova, N.A.Dukhovskiy, A.A., Artamonova, N.A., Belyayev, G.M., Nikishov, K.N.Structural controls on kimberlite formation in the Anabar megablockInternational Geology Review, Vol. 28, No. 11, Nov. pp. 1336-1345RussiaStructure, Tectonics, Geophysics, gravity
DS1986-0199
1986
Artamonova, N.A.Dukhovskiy, A.A., Artamonova, N.A., Dudko, E.A., MilshteinDeep structure of the Siberian platform kimberlite fields.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR (Russian), Vol. 290, No. 4, pp. 920-924RussiaTectonics
DS1988-0182
1988
Artamonova, N.A.Dukhovskiy, A.A., Artamonova, N.A., Duko, Ye.A., Milshteyn, Ye.D.Deep structure of the kimberlite fields of the Siberian PlatformDoklady Academy of Science USSR, Earth Science Section, Vol. 290, No. 1-6, March pp. 122-124RussiaStructure, Kimberlite fields
DS1986-0200
1986
Artaonova, N.A.Dukhovskiy, A.A., Artaonova, N.A., Dudko, E.A., Milstein, E.D.Deep structure of the Siberian platform kimberlite field.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 290, No. 4, pp. 920-924RussiaBlank
DS1986-0788
1986
ArtemenkoSukhorukova, T.Y., Nadezhdina, Y.D., Rumyantsev, G.S., ArtemenkoPhotoluminescence and EPR of non kimberlitic natural diamonds.(Russian)Doklady Academy of Sciences Nauk. SSSR (Russian), Vol. 286, No. 6, pp. 1498-1501RussiaBlank
DS1987-0722
1987
ArtemenkoSukhorukova, T.Yu., Nadezhdina, Ye.D., Rumyantsev, G.S., ArtemenkoPhotoluminescence and electron paramagnetic resonsance ofnatural diamonds of nonkimberlite originDokl. Acad. Sciences USSR Earth Science Section, Vol. 286, No. 1-6, September pp. 156-159RussiaBlank
DS200512-0971
2005
Artemenko, G.V.Shcherbak, N.P., Artemenko, G.V., Grinchenko, A.V.Age correlation of endogenic processes of the Slave (Canada) and Middle Peri Dneiper (Ukraine) cratons in connection with diamond bearing ability problems.Gems & Gemology, abstracts Mineralogical Journal (Ukraine) Vol. 26, 1, pp. 18-23. *** in English, Vol. 41, 2, Summer p. 194. abstract onlyEurope, Ukraine, CanadaGeochronology, cratons
DS201811-2560
2018
Artemenko, G.V.Claesson, S., Artemenko, G.V., Bogdanova, S.V., Shumlyanskyy, L.Archean crustal evolution in the Ukrainian shield.Earth's Oldest Rocks, Springer , Chapter 33, pp. 872-889.Europe, Ukrainetectonics
DS2001-0557
2001
ArtemievaKaban, M., Artemieva, Schwintzer, MooneyEstimating the density of the continental roots: compositional and thermaleffects.Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractMantleGeothermometry, Geophysics - gravity anomalies
DS2000-0033
2000
Artemieva, I.Artemieva, I., Mooney, W., Sleep, N.H.Deep structure and evolution of Archean cratonsGeological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-429.MantleCraton - tectonics, Precambrian lithosphere
DS2001-0050
2001
Artemieva, I.Artemieva, I., Mooney, W.Thermal thickness of cratonic lithosphere: a global studySlave-Kaapvaal Workshop, Sept. Ottawa, 6p. abstractMantleCraton - Precambrian lithosphere, Seismic tomography
DS2002-0795
2002
Artemieva, I.Kaban, M., Artemieva, I., Schwintzer, P., Mooney, W.D.Density of the continental roots: compositional and thermal effectsGeological Society of America Annual Meeting Oct. 27-30, Abstract p. 263.South AfricaGeothermometry - heat flow
DS2002-1044
2002
Artemieva, I.Meissener, R., Mooney, W.D., Artemieva, I.Seismic anisotropy and mantle creep in young orogensGeophysical Journal International, Vol.149,1,pp.1-14., Vol.149,1,pp.1-14.MantleGeophysics - seismics, Tectonics - orogeny
DS2002-1045
2002
Artemieva, I.Meissener, R., Mooney, W.D., Artemieva, I.Seismic anisotropy and mantle creep in young orogensGeophysical Journal International, Vol.149,1,pp.1-14., Vol.149,1,pp.1-14.MantleGeophysics - seismics, Tectonics - orogeny
DS201112-0030
2011
Artemieva, I.Artemieva, I.The Lithosphere: an inter disciplinary approach.cambridge.org/us/earth, 978-0-521-84396-6 800p. $ 145.00GlobalBook - advertisement
DS201312-0028
2013
Artemieva, I.Artemieva, I., Herceg, M., Cherepanova, Y., Thybo, H.Compositional heterogeneity of the upper mantle beneath the Siberian craton: reconciling thermal, seismic and gravity data.Goldschmidt 2013, AbstractRussiaGeophysics
DS201607-1327
2016
Artemieva, I.Artemieva, I.Density structure of the cratonic mantle in southern Africa, kimberlite distribution, mantle velocities, MOHO sharpness, and dynamic topograhy.IGC 35th., Session A Dynamic Earth 1 p. abstractAfrica, South AfricaGeodynamics
DS201607-1328
2016
Artemieva, I.Artemieva, I.Density structure of the cratonic mantle in Siberia, correlations with mantle petrology and kimberlite distribution.IGC 35th., Session A Dynamic Earth 1p. AbstractRussiaKimberlite
DS1989-0039
1989
Artemieva, I.M.Artemieva, I.M.Influence of volatiles in the upper mantle on The dynamics of thermal thinning of the lithosphereJournal of Geodynamics, Vol. 11, pp. 77-97Colorado Plateau, East African RiftTectonics, Mantle
DS2000-0321
2000
Artemieva, I.M.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
DS2002-0065
2002
Artemieva, I.M.Artemieva, I.M., Mooney, W.D.On the relations between cratonic lithosphere thickness, plate motions and basal dragTectonophysics, Vol. 358, 1-4, pp. 211-31.MantleSubduction, craton
DS2002-0066
2002
Artemieva, I.M.Artemieva, I.M., Mooney, W.D., Perchuc, E., Thybo, H.Processes of lithosphere evolution: new evidence on the structure of the continental crust and uppermost mantle.Tectonophysics, Vol. 358, 1-4, pp. 1-15.MantleTectonics
DS2002-0155
2002
Artemieva, I.M.Billien, M., Leveque, J.J., Artemieva, I.M., Mooney, W.D.Shear wave velocity, seismic attenuation and thermal structure of the continental lithosphere.Geological Society of America Annual Meeting Oct. 27-30, Abstract p. 263.South Africa, Russia, West AfricaGeophysics - seismics, Tectonics
DS2003-0037
2003
Artemieva, I.M.Artemieva, I.M.Structure and evolution of the continental lithosphereGeological Society of America, Annual Meeting Nov. 2-5, Abstracts p.14.North AmericaGeophysics - seismics, lithosphere
DS2003-0038
2003
Artemieva, I.M.Artemieva, I.M.Lithospheric structure composition and thermal regime of the East European Craton:Earth and Planetary Science Letters, Vol. 213, No. 3-4, pp. 431-46.RussiaGeothermometry
DS2003-0039
2003
Artemieva, I.M.Artemieva, I.M., Billen, M., Leveque, J.J.Shear wave velocity seismic attenuation and thermal structure of the continentalGeological Society of America, Annual Meeting Nov. 2-5, Abstracts p.14.North AmericaGeophysics - seismics, lithosphere
DS2003-0679
2003
Artemieva, I.M.Kaban, M., Schwintzer, P., Artemieva, I.M., Mooney, W.D.Density of the continental roots: compositional and thermal contributionsEarth and Planetary Science Letters, Vol. 209, 1-2, April 15, pp. 53-69.MantleGeophysics - gravity, geothermometry, heat flow, lithos, craton - East European, Siberia, Australia, India
DS2003-0680
2003
Artemieva, I.M.Kaban, M.K., Schwintzer, P., Artemieva, I.M., Mooney, W.D.Density of the continental roots: compositional and thermal contributionsEarth and Planetary Science Letters, Vol. 209, 1-2, pp. 53-69.MantleTectonics, Geothermometry
DS2003-0681
2003
Artemieva, I.M.Kaban, M.K., Schwintzer, P., Artemieva, I.M., Mooney, W.D.Density of the continental roots: compositional and thermal contributionsEarth and Planetary Science Letters, Vol. 209, 1-2, April 15, pp.53-69.Norway, Russia, Europe, Australia, India, South AfricaCratonic roots, Archean, Baltic shield, East European P, Siberian Platform
DS200412-0056
2003
Artemieva, I.M.Artemieva, I.M.Lithospheric structure composition and thermal regime of the East European Craton: implications for the subsidence of the RussiaEarth and Planetary Science Letters, Vol. 213, no. 3-4, pp. 431-46.RussiaGeothermometry
DS200412-0057
2003
Artemieva, I.M.Artemieva, I.M.Structure and evolution of the continental lithosphere.Geological Society of America, Annual Meeting Nov. 2-5, Abstracts p.14.United States, CanadaGeophysics - seismics, lithosphere
DS200412-0058
2003
Artemieva, I.M.Artemieva, I.M., Billen, M., Leveque, J.J.Shear wave velocity seismic attenuation and thermal structure of the continental lithosphere.Geological Society of America, Annual Meeting Nov. 2-5, Abstracts p.14.United States, CanadaGeophysics - seismics, lithosphere
DS200412-0059
2004
Artemieva, I.M.Artemieva, I.M., Billien, M., Leveque, J.J., Mooney, W.D.Shear wave velocity, seismic attenuation and thermal structure of the continental upper mantle.Geophysical Journal International, Vol. 157, 2, pp. 607-628.MantleGeophysics - seismics
DS200412-0941
2003
Artemieva, I.M.Kaban, M.K., Schwintzer, P., Artemieva, I.M., Mooney, W.D.Density of the continental roots: compositional and thermal contributions.Earth and Planetary Science Letters, Vol. 209, 1-2, April 15, pp.53-69.Europe, Norway, Russia, Australia, India, AfricaCratonic roots, Archean, Baltic shield, East European P Siberian Platform
DS200612-0039
2006
Artemieva, I.M.Artemieva, I.M.Global 1 X 1 thermal model TC1 for the continental lithosphere: implications for lithosphere secular evolution.Tectonophysics, Vol. 416, 1-4, April 5, pp. 245-277.MantleGeothermometry
DS200712-0027
2006
Artemieva, I.M.Artemieva, I.M.Growth, preservation and recycling rate of the lithosphere since the Archean.Geological Society of America Annual Meeting, Vol. 38, 7, Nov. p. 386. abstractMantleGeothermometry
DS200712-0028
2007
Artemieva, I.M.Artemieva, I.M.Dynamic topography of the East European Craton: shedding light upon lithospheric structure, composition and mantle dynamics.Global and Planetary Change, Vol. 58, 1-4, pp. 411-434.EuropeCraton, tectonics
DS200712-0029
2007
Artemieva, I.M.Artemieva, I.M.Dynamic topography of the East European Craton: shedding light upon lithospheric structure, composition and mantle dynamics.Global and Planetary Change, Vol. 58, 1-4, pp. 411-434.EuropeCraton, tectonics
DS200712-0030
2006
Artemieva, I.M.Artemieva, I.M., Thybo, H., Kaban, M.K.Deep Europe today: geophysical synthesis of the upper mantle structure and lithospheric processes over 3.5 Ga.Geological Society of London Memoir, No. 32, pp. 11-42.EuropeTectonics
DS200812-0048
2008
Artemieva, I.M.Artemieva, I.M.The continental lithosphere: reconciling thermal, seismic and petrologic data.Lithos, In press available 89p.MantleOverview
DS201112-0031
2011
Artemieva, I.M.Artemieva, I.M.Evolution of the cratonic lithosphere inferred from lithospheric mantle heterogeneity: a geophysical perspective.Goldschmidt Conference 2011, abstract p.455.MantleGeophysics - seismic tomography, global thermal
DS201312-0156
2013
Artemieva, I.M.Cherepanova, Y., Artemieva, I.M.Geophysical evidences for eclogites beneath the West Siberian basin.Goldschmidt 2013, AbstractRussiaAccretion
DS201312-0273
2013
Artemieva, I.M.Foulger, G.R., Panza, G.F., Artemieva, I.M., Bastow, I.D., Cammarano, F., Evans, J.R., Hamilton, W.B., Julian, B.R., Lustrino, M., Thybo, H., Yanovskaya, T.B.Caveat on tomographic images.Terra Nova, Vol. 25, 4, pp. 259-281.MantleSeismic tomography, geodynamics
DS201412-0126
2014
Artemieva, I.M.Cherepanova, Y., Artemieva, I.M.Density heterogeneity of the cratonic lithosphere: a case study of the Siberian craton.Gondwana Research, in press available 17p.RussiaKimberlites - metasomatism
DS201603-0369
2015
Artemieva, I.M.Cherepanova, Y., Artemieva, I.M.Density heterogeneity of the cratonic lithosphere: a case study of the Siberian craton.Gondwana Research, Vol. 28, 4, pp. 1344-1360.RussiaGeophysics - seismics

Abstract: Using free-board modeling, we examine a vertically-averaged mantle density beneath the Archean-Proterozoic Siberian Craton in the layer from the Moho down to base of the chemical boundary layer (CBL). Two models are tested: in Model 1 the base of the CBL coincides with the LAB, whereas in Model 2 the base of the CBL is at a 180 km depth. The uncertainty of density model is < 0.02 t/m3 or < 0.6% with respect to primitive mantle. The results, calculated at in situ and at room temperature (SPT) conditions, indicate a heterogeneous density structure of the Siberian lithospheric mantle with a strong correlation between mantle density variations and the tectonic setting. Three types of cratonic mantle are recognized from mantle density anomalies. ‘Pristine’ cratonic regions not sampled by kimberlites have the strongest depletion with density deficit of 1.8-3.0% (and SPT density of 3.29-3.33 t/m3 as compared to 3.39 t/m3 of primitive mantle). Cratonic mantle affected by magmatism (including the kimberlite provinces) has a typical density deficit of 1.0-1.5%, indicative of a metasomatic melt-enrichment. Intracratonic sedimentary basins have a high density mantle (3.38-3.40 t/m3 at SPT) which suggests, at least partial, eclogitization. Moderate density anomalies beneath the Tunguska Basin imply that the source of the Siberian LIP lies outside of the Craton. In situ mantle density is used to test the isopycnic condition of the Siberian Craton. Both CBL thickness models indicate significant lateral variations in the isopycnic state, correlated with mantle depletion and best achieved for the Anabar Shield region and other intracratonic domains with a strongly depleted mantle. A comparison of synthetic Mg# for the bulk lithospheric mantle calculated from density with Mg# from petrological studies of peridotite xenoliths from the Siberian kimberlites suggests that melt migration may produce local patches of metasomatic material in the overall depleted mantle.
DS201609-1698
2016
Artemieva, I.M.Artemieva, I.M., Thybo, H., Shulgin, A.Geophysical constraints on geodynamic processes at convergent margins: a global perspective.Gondwana Research, Vol. 33, pp. 4-23.MantleSubduction

Abstract: Convergent margins, being the boundaries between colliding lithospheric plates, form the most disastrous areas in the world due to intensive, strong seismicity and volcanism. We review global geophysical data in order to illustrate the effects of the plate tectonic processes at convergent margins on the crustal and upper mantle structure, seismicity, and geometry of subducting slab. We present global maps of free-air and Bouguer gravity anomalies, heat flow, seismicity, seismic Vs anomalies in the upper mantle, and plate convergence rate, as well as 20 profiles across different convergent margins. A global analysis of these data for three types of convergent margins, formed by ocean-ocean, ocean-continent, and continent-continent collisions, allows us to recognize the following patterns. (1) Plate convergence rate depends on the type of convergent margins and it is significantly larger when, at least, one of the plates is oceanic. However, the oldest oceanic plate in the Pacific ocean has the smallest convergence rate. (2) The presence of an oceanic plate is, in general, required for generation of high-magnitude (M > 8.0) earthquakes and for generating intermediate and deep seismicity along the convergent margins. When oceanic slabs subduct beneath a continent, a gap in the seismogenic zone exists at depths between ca. 250 km and 500 km. Given that the seismogenic zone terminates at ca. 200 km depth in case of continent-continent collision, we propose oceanic origin of subducting slabs beneath the Zagros, the Pamir, and the Vrancea zone. (3) Dip angle of the subducting slab in continent-ocean collision does not correlate neither with the age of subducting oceanic slab, nor with the convergence rate. For ocean-ocean subduction, clear trends are recognized: steeply dipping slabs are characteristic of young subducting plates and of oceanic plates with high convergence rate, with slab rotation towards a near-vertical dip angle at depths below ca. 500 km at very high convergence rate. (4) Local isostasy is not satisfied at the convergent margins as evidenced by strong free air gravity anomalies of positive and negative signs. However, near-isostatic equilibrium may exist in broad zones of distributed deformation such as Tibet. (5) No systematic patterns are recognized in heat flow data due to strong heterogeneity of measured values which are strongly affected by hydrothermal circulation, magmatic activity, crustal faulting, horizontal heat transfer, and also due to low number of heat flow measurements across many margins. (6) Low upper mantle Vs seismic velocities beneath the convergent margins are restricted to the upper 150 km and may be related to mantle wedge melting which is confined to shallow mantle levels.
DS201609-1699
2016
Artemieva, I.M.Artemieva, I.M., Vinnick, L.P.Density structure of the cratonic mantle in southern Africa: 1. Implications for dynamic topography.Gondwana Research, in press available 13p.Africa, South AfricaCratonic lithosphere

Abstract: The origin of high topography in southern Africa is enigmatic. By comparing topography in different cratons, we demonstrate that in southern Africa both the Archean and Proterozoic blocks have surface elevation 500-700 m higher than in any other craton worldwide, except for the Tanzanian Craton. An unusually high topography may be caused by a low density (high depletion) of the cratonic lithospheric mantle and/or by the dynamic support of the mantle with origin below the depth of isostatic compensation (assumed here to be at the lithosphere base). We use free-board constraints to examine the relative contributions of the both factors to surface topography in the cratons of southern Africa. Our analysis takes advantage of the SASE seismic experiment which provided high resolution regional models of the crustal thickness. We calculate the model of density structure of the lithospheric mantle in southern Africa and show that it has an overall agreement with xenolith-based data for lithospheric terranes of different ages. Density of lithospheric mantle has significant short-wavelength variations in all tectonic blocks of southern Africa and has typical SPT values of ca. 3.37-3.41 g/cm3 in the Cape Fold and Namaqua-Natal fold belts, ca. 3.34-3.35 g/cm3 in the Proterozoic Okwa block and the Bushveld Intrusion Complex, ca. 3.34-3.37 g/cm3 in the Limpopo Belt, and ca. 3.32-3.33 g/cm3 in the Kaapvaal and southern Zimbabwe cratons.The results indicate that 0.5-1.0 km of surface topography, with the most likely value of ca. 0.5 km, cannot be explained by the lithosphere structure within the petrologically permitted range of mantle densities and requires the dynamic (or static) contribution from the sublithospheric mantle. Given a low amplitude of regional free air gravity anomalies (ca. + 20 mGal on average), we propose that mantle residual (dynamic) topography may be associated with the low-density region below the depth of isostatic compensation. A possible candidate is the low velocity layer between the lithospheric base and the mantle transition zone, where a temperature anomaly of 100-200 °C in a ca. 100-150 km thick layer may explain the observed reduction in Vs velocity and may produce ca. 0.5-1.0 km to the regional topographic uplift.
DS201609-1700
2016
Artemieva, I.M.Artemieva, I.M., Vinnick, L.P.Density structure of the cratonic mantle in southern Africa: 2. Correlations with kimberlite distribution, seismic velocities, and Moho sharpness.Gondwana Research, Vol. 36, pp. 14-27.Africa, South AfricaKimberlite

Abstract: We present a new regional model for the depth-averaged density structure of the cratonic lithospheric mantle in southern Africa constrained on a 30' × 30' grid and discuss it in relation to regional seismic models for the crust and upper mantle, geochemical data on kimberlite-hosted mantle xenoliths, and data on kimberlite ages and distribution. Our calculations of mantle density are based on free-board constraints, account for mantle contribution to surface topography of ca. 0.5-1.0 km, and have uncertainty ranging from ca. 0.01 g/cm3 for the Archean terrains to ca. 0.03 g/cm3 for the adjacent fold belts. We demonstrate that in southern Africa, the lithospheric mantle has a general trend in mantle density increase from Archean to younger lithospheric terranes. Density of the Kaapvaal mantle is typically cratonic, with a subtle difference between the eastern, more depleted, (3.31-3.33 g/cm3) and the western (3.32-3.34 g/cm3) blocks. The Witwatersrand basin and the Bushveld Intrusion Complex appear as distinct blocks with an increased mantle density (3.34-3.35 g/cm3) with values typical of Proterozoic rather than Archean mantle. We attribute a significantly increased mantle density in these tectonic units and beneath the Archean Limpopo belt (3.34-3.37 g/cm3) to melt-metasomatism with an addition of a basaltic component. The Proterozoic Kheis, Okwa, and Namaqua-Natal belts and the Western Cape Fold Belt with the late Proterozoic basement have an overall fertile mantle (ca. 3.37 g/cm3) with local (100-300 km across) low-density (down to 3.34 g/cm3) and high-density (up to 3.41 g/cm3) anomalies. High (3.40-3.42 g/cm3) mantle densities beneath the Eastern Cape Fold belt require the presence of a significant amount of eclogite in the mantle, such as associated with subducted oceanic slabs. We find a strong correlation between the calculated density of the lithospheric mantle, the crustal structure, the spatial pattern of kimberlites, and their emplacement ages. (1) Blocks with the lowest values of mantle density (ca. 3.30 g/cm3) are not sampled by kimberlites and may represent the "pristine" Archean mantle. (2) Young (< 90 Ma) Group I kimberlites sample mantle with higher density (3.35 ± 0.03 g/cm3) than the older Group II kimberlites (3.33 ± 0.01 g/cm3), but the results may be biased by incomplete information on kimberlite ages. (3) Diamondiferous kimberlites are characteristic of regions with a low-density cratonic mantle (3.32-3.35 g/cm3), while non-diamondiferous kimberlites sample mantle with a broad range of density values. (4) Kimberlite-rich regions have a strong seismic velocity contrast at the Moho, thin crust (35-40 km) and low-density (3.32-3.33 g/cm3) mantle, while kimberlite-poor regions have a transitional Moho, thick crust (40-50 km), and denser mantle (3.34-3.36 g/cm3). We explain this pattern by a lithosphere-scale (presumably, pre-kimberlite) magmatic event in kimberlite-poor regions, which affected the Moho sharpness and the crustal thickness through magmatic underplating and modified the composition and rheology of the lithospheric mantle to make it unfavorable for consequent kimberlite eruptions. (5) Density anomalies in the lithospheric mantle show inverse correlation with seismic Vp, Vs velocities at 100-150 km depth. However, this correlation is weaker than reported in experimental studies and indicates that density-velocity relationship in the cratonic mantle is strongly non-unique.
DS1986-0787
1986
Artemky, V.V.Sukhoruki, T.I., Nadezhdiy, E.D., Ruminants, G.S., Artemky, V.V.Photoluminescence and electron paramagnetic res of natural nonkimberlitediamonds. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 286, No. 6, pp. 1498-1501RussiaDiamond morphology
DS2002-1802
2002
ArtemyevZorin, Y.A., Mordvinova, V.V., Turutanov, E.K., Belichenko, B.G., ArtemyevA low seismic velocity layers in the Earth's crust beneath Siberia and central Mongolia:Tectonophysics, Vol. 359, No. 3-4, pp. 307-27.Russia, Siberia, MongoliaGeophysics - seismics
DS1995-0249
1995
Arthaud, M.H.Caby, R., Arthaud, M.H., Archanjo, C.J.Lithostratigraphy and petrostructural characterization of supracrustal units in the Brasiliano belt of BrasilJournal of South American Earth Sciences, Vol. 8, No. 3-4, pp. 235-246BrazilStratigraphy, Petrology
DS1997-0811
1997
Arthaud, M.H.Monie, P., Caby, R., Arthaud, M.H.The Neoproterozoic Brasiliano Orogeny in northeast Brasil: 40 Ar/39Ar and petrostructural dat a CearaPrecambrian Research, Vol. 81. No. 3-4, Feb. 1, pp. 241-264BrazilTectonics, Argon, Proterozoic
DS200912-0666
2009
Arthaud, M.H.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
DS1998-0733
1998
ArthurKennedy, M.J., Runnegar, B., Prave, Hoffmann, ArthurTwo or four Neoproterozoic glaciations?Geology, Vol. 26, No. 12, Dec. pp. 1059-63.Africa, CongoCraton - Congo, Kalahari, Geomorphology
DS1970-0954
1974
Arthurs, J.W.Macfarlane, A., Crow, M.J., Arthurs, J.W., Wilkinson, A.F.The Geology and Mineral Resources of Northern Sierra Leone #1Overseas Institute of Geological Sciences International Report, No. 34, 203P.Sierra Leone, West AfricaKimberley, Geology, Diamonds
DS1975-1119
1979
Arthurs, J.W.Macfarlane, A., Crowe, M.J., Wilkinson, A.F., Arthurs, J.W.The Geology and Mineral Resources of Northern Sierra Leone #2Geological Survey SIERRA LEONE Bulletin., No. 7Sierra Leone, West AfricaGeology, Diamonds
DS1981-0276
1981
Arthurs, J.W.Macfarlane, A., Crow, M.J., Arthurs, J.W., Wilkinson, A.F., Auco.The Geology and Mineral Resources of Northern Sierra Leone #3Institute GEOL. SCIENCES OVERSEAS MEMOIR., MEMOIR No. 7, 103P. DIAMONDS PP. 65-66.Sierra Leone, West AfricaKimberley, Geology, Diamond
DS1999-0025
1999
Arthurs, J.W.Arthurs, J.W.Current activity in the minerals industry in Northern Ireland.... brief mention diamonds p. 24.North Atlantic Mineral Symposium, Sept., abstracts pp. 18-25.IrelandMinerals industry - overview general, Diamond prospecting p. 24.
DS1988-0758
1988
Artignan, D.Wilhelm, E., Artignan, D.L'analyse des mineraux lourds en exploration miniere: revuecritique etpropositions.(in French)Chronique de la Recherche Miniere, (in French), No. 490, March pp. 47-54GlobalBlank
DS1986-0759
1986
Artioli, G.Smyth, J.R., Smith, J.V., Artioli, G., Richardson, J.W.Jr., KvickCrystal structure of coesite at 15 and 198 K from single crystal eurton and X-ray diffraction, test of bonding modelsGeological Society of America (GSA) Abstract Volume, Vol. 18, No. 6, p. 756. (abstract.)South AfricaRoberts Victor deposit, Crystallography
DS1993-1056
1993
Artist-DowneyMitchell, R.H., Platt, R.G., Lukosius-Sanders, J., Artist-DowneyPetrology of syenites from centre III of the Coldwell alkaline complex, northwestern Ontario, CanadaCanadian Journal of Earth Sciences, Vol. 30, No. 1, January pp. 145-158OntarioAlkaline rocks, Coldwell Complex
DS1960-0011
1960
Artsybasheva, G.F.Artsybasheva, G.F.Massive Kimberlites of the River Alakit (western Yakutia)Vsegei, No. 40, Russia, AlakitBlank
DS1960-0419
1964
Artsybasheva, T.F.Artsybasheva, T.F., Blagulkina, V.A., et al.The Problem of Classification of the Yakutia Kimberlites (based on Those of the Alakit-daldynsk Diamantiferous Region).International Geology Review, Vol. 6, No. 10, PP. 1773-1781.RussiaKimberlite
DS1983-0110
1983
Artyushkov, E.V.Artyushkov, E.V., Sobolev, S.V.Physics of Kimberlite Magmatism: AppendixAnnales Scientifiques De L' Universite De Clermont-ferrand Ii, No. 74, PP. 137-140.RussiaTechnical Caluculations
DS1984-0117
1984
Artyushkov, E.V.Artyushkov, E.V., Sobolev, S.V.Physics of Kimberlite MagmatismProceedings of Third International Kimberlite Conference, Vol. 1, PP. 308-321.GlobalGenesis, Model, Diapir-crack
DS1998-0049
1998
Artyushkov, E.V.Artyushkov, E.V., Morner, N.A.Steep bending of continental lithosphere without its stretching or platecollision: an indication ...Terra Nova, Vol. 10, No. 2, pp. 101-5.MantleLithosphere - phase transitions, Tectonics
DS2000-0034
2000
Artyushkov, E.V.Artyushkov, E.V., Baer, M.A., Chekhovich, P.A.Mechanisms of an Early Paleozoic subsidence of continental crust inUrals: metamorphism lower crustDoklady Academy of Sciences, Vol. 373, No. 5, June-July, pp.777-81.Russia, UralsTectonics - subsidence, metamorphism
DS2003-0040
2003
Artyushkov, E.V.Artyushkov, E.V.Abrupt continental lithosphere weakening as a precondition for fast and large scaleGeotectonics, Vol. 37, 2, pp. 107-123.RussiaTectonics
DS200412-0060
2003
Artyushkov, E.V.Artyushkov, E.V.Abrupt continental lithosphere weakening as a precondition for fast and large scale tectonic movements.Geotectonics, Vol. 37, 2, pp. 107-123.RussiaTectonics
DS201901-0004
2018
Artyushkov, E.V.Artyushkov, E.V., Korikovsky, S.P., Massonne, H-J., Checkhovich, P.A.Recent crustal uplift of Precambrian cratons: key patterns and possible mechanisms.Russian Geology and Geophysics, Vol. 59, 11, pp. 1389-1409.Russiacraton

Abstract: Precambrian cratons cover about 70% of the total continental area. According to a large volume of geomorphological, geological, paleontological, and other data for the Pliocene and Pleistocene, these cratons have experienced a crustal uplift from 100-200 m to 1000-1500 m, commonly called the recent or Neotectonic uplift. Shortening of the Precambrian crust terminated half a billion years ago or earlier, and its uplift could not have been produced by this mechanism. According to the main models of dynamic topography in the mantle, the distribution of displacements at the surface is quite different from that of the Neotectonic movements. According to seismic data, there is no magmatic underplating beneath most of the Precambrian cratons. In most of cratonic areas, the mantle lithosphere is very thick, which makes its recent delamination unlikely. Asthenospheric replacement of the lower part of the mantle lithosphere beneath the Precambrian cratons might have produced only a minor part of their Neotectonic uplifts. Since the above mechanisms cannot explain this phenomenon, the rock expansion in the crustal layer is supposed to be the main cause of the recent uplift of Precambrian cratons. This is supported by the strong lateral nonuniformity of the uplift, which indicates that expansion of rocks took place at a shallow depth. Expansion might have occurred in crustal rocks that emerged from the lower crust into the middle crust with lower pressure and temperature after the denudation of a thick layer of surface rocks. In the dry state, these rocks can remain metastable for a long time. However, rapid metamorphism accompanied by expansion of rocks can be caused by infiltration of hydrous fluids from the mantle. Analysis of phase diagrams for common crustal rocks demonstrates that this mechanism can explain the recent crustal uplift of Precambrian cratons.
DS202008-1366
2020
Artyushkov, E.V.Artyushkov, E.V., Kolka, V.V., Chekhovich, P.A.The occurrence of lower viscosity layer in the crust of old cratons as a cause of the strongly differentiated character of postglacial uplift.Doklady Earth Sciences, Vol. 492, pp. 351-355.Europe, Fennoscandia, Kola Peninsula, Karelia, Canadacraton

Abstract: Rapid glacio-isostatic rebound in Fennoscandia and Canada that is nonuniform in time and space indicates that there is a layer with strongly decreased viscosity at shallow crustal depths. The upper boundary of the layer is near the depth of 15 km, which corresponds to the maximum depth of earthquake hypocenters in the Precambrian cratons of the Kola Peninsula and Karelia. The position of the lower boundary is less distinct; however, most likely it is located near the base of the crust. The formation of such a layer in the Pliocene-Quaternary occurred due to infiltration of a large volume of mantle fluids into the crust. In many regions, this has led to retrograde metamorphism with rock expansion and a strong decrease in rocks viscosity.
DS1996-0046
1996
Artyushkov, Ye. V.Artyushkov, Ye. V.To what depth does mantle convection caused by plate drift extend?Doklady Academy of Sciences, Vol. 342 No. 4, May, pp. 87-92.MantlePetrology - experimental, Tectonics
DS200712-0144
2007
AruajoCarlson, 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
AruajoCarlson, 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
DS1988-0076
1988
Arvidson, R.A.Bowring, S.A., Arvidson, R.A., Podosek, F.A.The Missouri gravity low: evidence for a cryptic suture?Geological Society of America Abstracts with Program, Vol. 20, No. 2, January p. 91. Sth. Central, LawrenceMissouriBlank
DS1981-0069
1981
Arvidson, R.E.Arvidson, R.E., Guinness, E.A.Integration of Remote Sensing, Geophysical and Geological Dat a Sets to Better Understand the Structural Geology of the St. Francois MountainsInstitute ELECTR. ELECTRON. ENG., Symposium Vol., PP. 895-896.GlobalMid-continent
DS1982-0073
1982
Arvidson, R.E.Arvidson, R.E., Guiness, E.A., Strebeck, J.W., Davies, G.F.Image Processing Applied to Gravity and Topography Dat a Covering the Continental United States (us)Eos, Vol. 63, No. 18, MAY 4TH. PP. 261-265.GlobalMid Continent
DS1982-0074
1982
Arvidson, R.E.Arvidson, R.E., Guinness, E.A., Strebeck, J.W.Structure of the Mid-continent Basement: Topography, Gravity,seismic and Remote Sensing Data.Cospar Plenary Meet. Program Abstracts, Vol. 24, P. 87. (abstract.).GlobalMid-continent
DS1982-0229
1982
Arvidson, R.E.Guinness, E.A., Arvidson, R.E., et al.Identification of a Precambrian Rift through Missouri by Digital Image Processing of Geophysical and Geological Data.Journal of GEOPHYSICAL RESEARCH, Vol. 87, No. B10, Oct. 10, PP. 8529-8546.GlobalMid-continent
DS1983-0111
1983
Arvidson, R.E.Arvidson, R.E., Guiness, E.A., Leff, C.E.New Perspectives on the Crustal Structure of MissouriGeological Society of America (GSA), Vol. 15, No. 6, P. 517. (abstract.).GlobalMid Continent
DS1983-0112
1983
Arvidson, R.E.Arvidson, R.E., Guinness, E.A., Bindschadler, D.L.Structure of the St. Francois Mountains and Surrounding Lead Belt Southeast Missouri: Inferences from Thermal Infrared and Other Dat a Sets.Nasa National Technical Information Service Final Report., No. E84-10027, 78P.United States, MissouriMid Continent
DS1992-1497
1992
Arvidson, R.E.Sultan, M., Bickford, M.E., El Kaliouby, B., Arvidson, R.E.Common lead systematics of Precambrian granitic rocks of the Nubian Egypt and tectonic implicationsGeological Society of America (GSA) Bulletin, Vol 104, No. 4, April pp. 456-470EgyptOphiolite, Tectonics
DS200612-0040
2006
Arvidson, R.S.Arvidson, R.S., Mackenzie, F.T., Guidry, M.MAGic: a Phanerozoic model for the geochemical cycling of major rock forming components.American Journal of Science, Vol. 306, 3, pp. 135-190.TechnologyComputer program - MAGic, geochemistry
DS1996-0047
1996
Arzamastesev, A.Arzamastesev, A., Glaznev, V., Raevsky, A.Deep structure of Precambrian basement in the area of the Kola alkalineprovince: geophysics and petrogenesisInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 1, p. 111.Russia, Kola PeninsulaGeophysics, Tectonics
DS202010-1843
2020
Arzamastesev, A.A.Erofeeva, K.G., Samsonov, A.V., Stepanova, A.V., Larionova, Yu.O., Dubinina, E.O., Egorova, S.V., Arzamastesev, A.A., Kovalchuk, E.V., Abramova, V.D.Olivine and clinopyroxene phenocrysts as a proxy for the origin and crustal evolution of primary mantle melts: a case study of 2.40 Ga mafic sills in the Kola-Norwegian Terrane, northern Fennoscandia.Petrology, Vol. 28, 4, pp. 338-356. pdfEurope, Norway, Kola Peninsulamelting

Abstract: New petrographic, geochemical, and isotopic (Sr, Nd, and d18?) data on olivine and pyroxene phenocrysts provide constraints on the composition and crustal evolution of primary melts of Paleoproterozoic (2.40 Ga) picrodoleritic sills in the northwest Kola province, Fennoscandian Shield. The picrodolerites form differentiated sills with S-shaped compositional profiles. Their chilled margins comprise porphyritic picrodolerite (upper margin) and olivine gabbronorite (bottom) with olivine and clinopyroxene phenocrysts. Analysis of the available data allows us to recognize three main stages in the crystallization of mineral assemblages. The central parts of large (up to 2 mm) olivine phenocrysts (Ol-1-C) crystallized at the early stage. This olivine (Mg# 85-92) is enriched in Ni (from 2845 to 3419 ppm), has stable Ni/Mg ratio, low Ti, Mn and Co concentrations, and contains tiny (up to 10 µm) diopside-spinel dendritic lamella that probably originated due to the exsolution from high Ca- and Cr- primary magmatic olivine. All these features of Ol-1-C are typical of olivine from primitive picritic and komatiitic magmas (De Hoog et al., 2010; Asafov et al., 2018). Ol-1-C contains large (up to 0.25 mm) crystalline inclusions of high-Al enstatite (Mg# 80-88) and clinopyroxene (Mg# 82-90), occasionally in association with Ti-pargasite and chromian spinel (60.4 wt.% Al2O3). These inclusions are regarded as microxenoliths of wall rock that were captured by primary melt at depths more than 30 km and preserved due to the conservation in magmatic olivine. The second stage was responsible for the crystallization of Ol-1 rim (Ol-1-R), small (up to 0.3 mm) olivine (Ol-2, Mg# 76-85) grains, and central parts of large (up to 1.5 mm) clinopyroxene (Cpx-C) phenocrysts in the mid-crustal transitional magma chamber (at a depth of 15-20 km) at 1160-1350°C. At the third stage, Cpx-C phenocrysts were overgrown by low-Mg rims (Mg# 70-72) similar in composition to the groundmass clinopyroxene from chilled picrodolerite and gabbro-dolerite in the central parts of the sills. This stage likely completed the evolution of picrodoleritic magma and occurred in the upper crust at a depth of about 5 km. All stages of picrodoleritic magma crystallization were accompanied by contamination. Primary melts were contaminated by upper mantle and/or lower crust as recognized from xenocrystic inclusions in Ol-1-C. The second contamination stage is supported by the negative values of eNd(2.40) = -1.1 in clinopyroxene phenocrysts. At the third stage, contamination likely occurred in the upper crust when ascending melts filled gentle fractures. This caused vertical whole-rock Nd heterogeneity in the sills (Erofeeva et al., 2019), and difference in Nd isotopic composition of clinopyroxene phenocrysts and doleritic groundmass. It was also recognized that residual evolved melts are enriched in radiogenic strontium but have neodymium isotopic composition similar to other samples. It could be explained by the interaction of the melts with fluid formed via decomposition of biotite from surrounding gneisses under the effect of high-temperature melts.
DS1994-0065
1994
Arzamastev, A.Arzamastev, A., Arzmastseva, L.A.Ultramafic foidite series of the Kola Peninsula Russia: estimates of P and Sr productivity.9th. IAGOD held Beijing, Aug.12-18., pp. 706. abstractRussia, Kola PeninsulaMelilite
DS1995-0061
1995
Arzamastev, A.Arzamastev, A., et al.Three dimensional modelling of deep structure of carbonatite intrusions Of the Kola Province.Terra Nova, Abstract Vol. p. 59.Russia, Kola PeninsulaCarbonatite
DS2001-0094
2001
Arzamastev, A.Bea, F., Arzamastev, A., Arzamastseva, L.Anomalous alkaline rocks of Soustov, Kola: evidence of mantle derived metasomatic fluids affecting crustal ..Contributions to Mineralogy and Petrology, Vol. 140, No. 5, pp. 554-66.Russia, Kola PeninsulaMetasomatism
DS202009-1608
2019
Arzamastev, A.Arzamastev, A., Stepanova, A.V., Samsonov, A.V., Erofeev, K.G.Mafic magmatism of northeastern Fennoscandia ( 2.06-1.86 Ga) geochemistry of volcanic rocks and correlation with dike complexes.Stratigraphy and Geological Correlation, Vol. 28, 1, pp. 1-34.Europe, Fennoscandiamagmatism

Abstract: The comprehensive geochemical and isotopic-geochronological study of Early Proterozoic volcanic rocks in structure of the Polmak-Pechenga-Imandra-Varzuga belt and dikes and sills of the Murmansk and Kola-Norwegian terranes is conducted. Abundant swarms of mafic dikes (2.06-1.86 Ga) are established in the northwestern frame of the belt, including swarms of metadolerites (2060 ± 6 Ma), ferropicrites and gabbronorites (1983 ± 5 Ma), and poikilophitic dolerites (1860 ± 4 Ma). The comparison of volcanic rocks of the Pechenga and Imandra-Varzuga structures shows asynchronous change in volcanism style, with a significant time lapse. The geochemical features of volcanic rocks of the Tominga Formation are typical of those of continental magmatism and can hardly be correlated with those of the Pilguyarvi Formation. According to isotopic-geochronological data, depleted mantle melts in the Pechenga and Imandra-Varzuga zones intruded at 2010-1970 and 1970-1980 Ma, respectively. The analysis of the conditions of formation of volcanic series shows that Neoarchean lithospheric mantle, which produced melts with low Zr/Nb ratios, was a source for primary melts of the Kuetsjarvi Formation of the Pechenga structure and their homologs of the Imandra-Varzuga structure. In contrast, the volcanic rocks of the Kolasjoki Formation, which were weakly contaminated with crustal material, and the related Ilmozero Formation, as well as the metadolerite dikes of the Kirkenes region, were sourced mostly from asthenosphere with separation of melt above the garnet stability depth. The formation of the volcanic rocks of the Pilguyarvi Formation is related, judging from the geochemical data, to two asthenospheric sources different in depth, which produced tholeiitic and ferropicritic melts.
DS1992-0816
1992
Arzamastev, A.A.Kalinkin, M.M., Arzamastev, A.A.Alkalic ultramafics in diatremes on the Terskiy coast of the KolaPeninsula: a new type of Paleozoic magmatismDoklady Academy of Sciences USSR, Earth Science Section, Vol. 316, No. 1-9, December pp. 162-165Russia, Commonwealth of Independent States (CIS)Alkalic rocks, Diatremes
DS1994-0066
1994
Arzamastev, A.A.Arzamastev, A.A., Dahlgren, S.Plutonic mineral assemblages in dikes and explosion pipes in Paleozoic alkaline province of Baltic Shield.Geochemistry International, Vol. 31, No. 3, pp. 57-68.Baltic Shield, KolaAlkaline rocks, Diatremes
DS2003-0041
2003
Arzamastev, A.A.Arzamastev, A.A., Travin, A.V., Belyatskii, B.V., Arzamasteva, L.V.Paleozoic dike series in the Kola alkaline province: age and characteristics of mantleDoklady Earth Sciences, Vol. 391, 6a, pp. 906-909.Russia, Kola PeninsulaCarbonatite, geochronology
DS200412-0061
2003
Arzamastev, A.A.Arzamastev, A.A., Travin, A.V., Belyatskii, B.V., Arzamasteva, L.V.Paleozoic dike series in the Kola alkaline province: age and characteristics of mantle sources.Doklady Earth Sciences, Vol. 391, 6a, pp. 906-909.Russia, Kola PeninsulaCarbonatite, geochronology
DS200612-0041
2006
Arzamastev, A.A.Arzamastev, A.A., Bea, F., Arzamastseva, L.V., Montero, P.Proterozoic Gremyakha-Vyrmes polyphase massif, Kola Peninsula: an example of mixing basic and alkaline mantle melts.Petrology, Vol. 14, 4, pp. 361-389.Russia, Kola PeninsulaAlkalic
DS200812-0049
2008
Arzamastev, A.A.Arzamastev, A.A., Glaznev, V.N.Plume lithosphere interaction in the presence of an ancient sublithospheric mantle keel: an example from the Kola alkaline province.Doklady Earth Sciences, Vol. 419A, no. 3, pp. 384-387.Russia, Kola PeninsulaMantle plume
DS201112-0032
2011
Arzamastev, A.A.Arzamastev, A.A., Arzamasteva, L.V.Paleozoic tholeiite magmatism in the Kola Province, Russia: relations with alkaline magmatism.Goldschmidt Conference 2011, abstract p.456.Russia, Kola PeninsulaCarbonatite, Khibina, Lovozero
DS201412-0018
2014
Arzamastev, A.A.Arzamastev, A.A., Wu, F-Y.U Pb geochronology and Sr-Nd isotopic systematics of minerals from the ultrabasic-alkaline massifs of the Kola province.Petrology, Vol. 22, 5, pp. 462-479.Russia, Kola PeninsulaAlkalic
DS201510-1757
2014
Arzamastev, A.A.Arzamastev, A.A., Arztmasteva, L.V., Zhirova, A.M., Glaznev, V.N.Model of formation of the Khibiny-Lovozero ore bearing volcanic-plutonic complex.Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 124-147.Baltic Shield, FennoscandiaCarbonatite, alkaline rocks

Abstract: The paper presents the results of a study of the large Paleozoic ore-magmatic system in the northeastern Fennoscandian Shield comprising the Khibiny and Lovozero plutons, the Kurga intrusion, volcanic rocks, and numerous alkaline dike swarms. As follows from the results of deep drilling and 3D geophysical simulation, large bodies of rocks pertaining to the ultramafic alkaline complex occur at the lower level of the ore-magmatic system. Peridotite, pyroxenite, melilitolite, melteigite, and ijolite occupy more than 50 vol % of the volcanic-plutonic complex within the upper 15 km accessible to gravity exploration. The proposed model represents the ore-magmatic system as a conjugate network of mantle magmatic sources localized at different depth levels and periodically supplying the melts belonging to the two autonomous groups: (1) ultramafic alkaline rocks with carbonatites and (2) alkali syenites-peralkaline syenites, which were formed synchronously having a common system of outlet conduits. With allowance for the available isotopic datings and new geochronological evidence, the duration of complex formation beginning from supply of the first batches of melt into calderas and up to postmagmatic events, expressed in formation of late pegmatoids, was no less than 25 Ma.
DS2001-0051
2001
Arzamasteva, L.V.Arzamastsevm A.A., Bea, F., Glaznev, V.N., Arzamasteva, L.V., Montero, P.Kola alkaline province in the Paleozoic: evaluation of primary mantle magma composition and magma generation conditions.Russian Journal of Earth Science, Vol. 3, 1, March, pp.Russia, Kola PeninsulaMagmatism
DS2002-0067
2002
Arzamasteva, L.V.Arzamastsev, A.A., Bea, F., Arzamasteva, L.V., Montero, P.Rare earth elements in rocks and minerals from alkaline plutons of the Kola Peninsula, NW Russia, as indicators of alkaline magma evolution.Russian Journal of Earth Science, Vol. 4, 3, JuneRussia, Kola PeninsulaREE
DS2003-0041
2003
Arzamasteva, L.V.Arzamastev, A.A., Travin, A.V., Belyatskii, B.V., Arzamasteva, L.V.