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SDLRC - Scientific Articles all years by Author - Ho+


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 - Ho+
Posted/
Published
AuthorTitleSourceRegionKeywords
DS2003-0247
2003
Ho, K.Chen, J., Hsu, C., Ho, K.Geochemistry of Cenozoic volcanic rocks and related ultramafic xenoliths from the JilinJournal of Asian Earth Sciences, Vol. 21, 9, pp. 1069-1084.ChinaXenoliths
DS200412-0318
2003
Ho, K.Chen, J., Hsu, C., Ho, K.Geochemistry of Cenozoic volcanic rocks and related ultramafic xenoliths from the Jilin and Heilongjiang provinces, northeast ChJournal of Asian Earth Sciences, Vol. 21, 9, pp. 1069-1084.ChinaXenoliths
DS1987-0260
1987
Ho, S.E.Groves, D.I., Ho, S.E., Rock, N.M.S., Barley, M.E., Muggeridge, M.T.Archean cratonsGeology, Vol. 15, No. 9, September pp. 801-805Canada, Wyoming, Southern Africa, Zimbabwe, Russia, AustraliaTectonics, Craton
DS1992-0582
1992
Ho, S.E.Glover, J.E., Ho, S.E.The Archean: terrains, processes and metallogenyUniversity of Western Australia, o. 22, $ 79.00Australia, Russia, Canada, Quebec, northwest Territories, South AfricaArchean, terrains, processes, metallogeny, Gold deposits
DS201502-0062
2014
Hoag, H.Hoag, H.Earth's deep crust could support Wide spread life.Nature, Dec. 23, 1p.MantleMicrobial ecosystems
DS1985-0289
1985
Hoal, B.G.Hoal, B.G.Preliminary Report on the Geology of the South Eastern Partof Diamond Area No. 2, Southwest Africa/namibia.Communs. Geological Survey Swa/namibia., Vol. 1, PP. 9-21. 1 MAP.Southwest Africa, NamibiaLithology, Kairab, Garub, Sinclair, Haiber Flats, Structure, Metam
DS1994-0201
1994
Hoal, B.G.Boyd, F.R., Pearson, D.G., Olson Hoal, K.E., Hoal, B.G.Composition and age of Namibian peridotite xenolith: a comparison of cratonic and non cratonic lithosphere.Eos, Vol. 75, No. 16, April 19, p. 192.NamibiaXenoliths, Peridotites
DS1995-0804
1995
Hoal, B.G.Hoal, B.G., Hoal, K.E.O., Boyd, F.R., Pearson, D.G.Tectonic setting and mantle composition inferred from peridotite Gibeon kimberlite field, Namibia.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 239-241.NamibiaTectonics, Deposit -Gibeon area
DS1995-0805
1995
Hoal, B.G.Hoal, B.G., Hoal, R.E.O., Boyd, F.R., Pearson, D.G.Age constraints on crustal and mantle lithosphere beneath the Gibean kimberlite field, Namibia.South. African Journal of Geology, Vol. 98, No. 2, June pp. 112-118.NamibiaGeochronology, Deposit -Gibeon field
DS2003-0146
2003
Hoal, B.G.Boyd, F.R., Hoal, K.O., Hoal, B.G., Nicox, P.H., Pearson, D.G., Kingston, M.J.Garnet lherzolites from Louwrencia, Namibia: bulk sample compositions and P/T8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, AbstractNamibiaMantle petrology
DS200412-0193
2003
Hoal, B.G.Boyd, F.R., Hoal, K.O., Hoal, B.G., Nicox, P.H., Pearson, D.G., Kingston, M.J.Garnet lherzolites from Louwrencia, Namibia: bulk sample compositions and P/T relations.8 IKC Program, Session 6, AbstractAfrica, NamibiaMantle petrology
DS200412-0197
2004
Hoal, B.G.Boyd, S.R., Pearson, D.G., Hoal, K.O., Hoal, B.G., Nixon, P.H., Kingston, M.J., Mertzman, S.A.Garnet lherzolites from Louwrensia, Namibia: bulk composition and P/T relations.Lithos, Vol. 77, 1-4, Sept. pp. 573-592.Africa, NamibiaGeothermometry, peridotite, Kaapvaal, mantle, lithosphe
DS2001-0481
2001
Hoal, K.Hoal, K.Samples of iron enriched Bushveld mantle from the Premier kimberliteSlave-Kaapvaal Workshop, Sept. Ottawa, 5p. abstractSouth AfricaMineralogy - petrology - major, trace elements, Deposit - Premier
DS200912-0304
2009
Hoal, 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
DS1995-0804
1995
Hoal, K.E.O.Hoal, B.G., Hoal, K.E.O., Boyd, F.R., Pearson, D.G.Tectonic setting and mantle composition inferred from peridotite Gibeon kimberlite field, Namibia.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 239-241.NamibiaTectonics, Deposit -Gibeon area
DS2003-0146
2003
Hoal, K.O.Boyd, F.R., Hoal, K.O., Hoal, B.G., Nicox, P.H., Pearson, D.G., Kingston, M.J.Garnet lherzolites from Louwrencia, Namibia: bulk sample compositions and P/T8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, AbstractNamibiaMantle petrology
DS2003-0591
2003
Hoal, K.O.Hoal, K.O.Samples of Proterozoic iron enriched mantle from the Premier kimberliteLithos, Vol. 71, 2-4, pp. 259-72.South AfricaMineralogy
DS200412-0193
2003
Hoal, K.O.Boyd, F.R., Hoal, K.O., Hoal, B.G., Nicox, P.H., Pearson, D.G., Kingston, M.J.Garnet lherzolites from Louwrencia, Namibia: bulk sample compositions and P/T relations.8 IKC Program, Session 6, AbstractAfrica, NamibiaMantle petrology
DS200412-0197
2004
Hoal, K.O.Boyd, S.R., Pearson, D.G., Hoal, K.O., Hoal, B.G., Nixon, P.H., Kingston, M.J., Mertzman, S.A.Garnet lherzolites from Louwrensia, Namibia: bulk composition and P/T relations.Lithos, Vol. 77, 1-4, Sept. pp. 573-592.Africa, NamibiaGeothermometry, peridotite, Kaapvaal, mantle, lithosphe
DS200412-0838
2003
Hoal, K.O.Hoal, K.O.Samples of Proterozoic iron enriched mantle from the Premier kimberlite.Lithos, Vol. 71, 2-4, pp. 259-72.Africa, South AfricaMineralogy
DS200712-0443
2006
Hoal, K.O.Hoal, K.O.Integrating the diamond project development process.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.134-5. abstract onlyGlobalEconomics
DS200812-0477
2008
Hoal, K.O.Hoal, K.O.Getting the Geo into Geomet. 'geometallurgy'...SEG Newsletter, No. 73, April p. 1, 11-15.TechnologyGeometallurgy
DS200912-0305
2009
Hoal, K.O.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
DS1995-0805
1995
Hoal, R.E.O.Hoal, B.G., Hoal, R.E.O., Boyd, F.R., Pearson, D.G.Age constraints on crustal and mantle lithosphere beneath the Gibean kimberlite field, Namibia.South. African Journal of Geology, Vol. 98, No. 2, June pp. 112-118.NamibiaGeochronology, Deposit -Gibeon field
DS201312-0725
2013
Hoang, N.Quoc Cuong, N., Zuchiewicz, W., Hoang, N., Flower, M.F.J., Thong Chi, C., Mocanu, V.Plate assembly, tectonic responses, and magmatism in southeast Eurasia.Journal of Geodynamics, in press availableEurope, AsiaCraton
DS201910-2264
2019
Hoare, B.Hoare, B., Tomlinson, E., Balz, K.Fossil geotherms frozen in diamond require very deep ( >300 km) Early Kalahari cratonic lithosphere.Goldschmidt2019, 1p. AbstractAfrica, South Africageothermometry

Abstract: In the Archaean, global surface heat flow was substantially higher than today because of greater internal radiogenic heat production and primordial heat content within the Earth. Nonetheless, the lithospheric roots of Archaean cratons were apparently surprisingly cool, recording similarly low ambient temperatures to those inferred today, allowing e.g. for the stabilisation of diamond. This finding is seemingly in conflict with a generally ‘hotter’ Archaean mantle, as is widely postulated, but the paradox could be explained if the sub-cratonic lithospheric mantle was substantially thicker in the Archaean than today. Here, we report a re-investigation of the thermal structure of the Archaean Kalahari lithosphere using published and unpublished petrological data of diamond inclusions indicated to be of Archaean age. Our thermobarometric calculations agree with earlier findings that the Archaean cratonic mantle root was surprisingly cool. Importantly, the shape of the inclusion-derived P-T array deviates from the modern geotherm recorded by peridotite xenoliths. Specifically, diamond inclusions define a systematically steeper geothermal gradient than is observed in cratonic xenoliths. We find that Archaean diamond inclusion and modern xenolith P-T data cannot be reconciled by a single steady-state geotherm. The P-T conditions recorded in diamond inclusions are incompatible with the current characteristically low present-day heat-production of the overlying crust. Instead, the steeper geotherm implies high heat production in the crust during diamond formation and the distinctive geothermal gradient recorded in the studied diamond inclusions could reflect ancient mantle conditions. We modelled a suite of ‘fossil’ geotherms, with increased radiogenic heat production within the crust during the Archaean. Solutions providing very good fits with the diamond inclusion geotherm all require that the Archaean lithosphere must have extended to far greater depths than is preserved today. The required depth ranges from ~ 300 km to ~ 450 km depth, for a modern (~ 1350°C) and a significantly hotter (~ 1600°C) mantle potential temperature, respectively. In either case, it is clear that the Kalahari lithosphere must have experienced significant (at least 100 km) basal erosion subsequent to its formation.
DS201805-0983
2018
Hoare, B.C.Tomlinson, E.L., Kamber, B.S., Hoare, B.C., Stead, C.V., Ildefonse, B.An exsolution origin for Archean mantle garnet. C-SCLM KaapvaalGeology, Vol. 46, 2, pp. 123-126.Africa, South Africacraton

Abstract: It is well established that the cratonic subcontinental lithospheric mantle (C-SCLM) represents a residue of extensively melted peridotite. The widespread occurrence of garnet in C-SCLM remains a paradox because experiments show that it should be exhausted beyond ~20% melting. It has been suggested that garnet may have formed by exsolution from Al-rich orthopyroxene; however, the few documented examples of garnet exsolution in cratonic samples are exotic and do not afford a direct link to garnet in granular harzburgite. We report crystallographic, petrographic, and chemical data for an exceptionally well preserved orthopyroxene megacryst containing garnet lamellae, juxtaposed against granular harzburgite. Garnet lamellae are homogeneously distributed within the host orthopyroxene and occur at an orientation that is unrelated to orthopyroxene cleavage, strongly indicating that they formed by exsolution. Garnet lamellae are subcalcic Cr-pyrope, and the orthopyroxene host is high-Mg enstatite; these phases equilibrated at 4.4 GPa and 975 °C. The reconstructed precursor is a high-Al enstatite that formed at higher pressure and temperature conditions of ~6 GPa and 1750 °C. The megacryst shows evidence for disintegrating into granular peridotite, and garnet and orthopyroxene within the granular peridotite are texturally and chemically identical to equivalent phases in the megacryst. Collectively, this evidence supports a common origin for the granular and exsolved portions of the sample. We hypothesize that high-Al enstatite was a common phase in the C-SCLM and that exsolution during cooling and stabilization of the C-SCLM could be the origin of most subcalcic garnets in depleted peridotites.
DS201709-2065
2017
Hoare, C.V.Tomlinson, E.L., Kamber, B.C., Hoare, C.V., Stead, C.V., Ildefonse, B.An exsolution origin for Archaean mantle garnet.Goldschmidt Conference, abstract 1p.Mantlegarnet

Abstract: It is now well established that the cratonic sub-continental lithospheric mantle (SCLM) represents a residue of extensively melted fertile peridotite. The widespread occurrence of garnet in the Archaean SCLM remains a paradox because many experiments agree that garnet is exhausted beyond c. 20% melting. It has been suggested that garnet may have formed by exsolution from Al-rich orthopyroxene [1,2,3]. However, the few examples of putative garnet exsolution in cratonic samples remain exotic and have not afforded a link to garnet that occurs as distinct grains in granular harzburgite. We present crystallographic (EBSD), petrographic and chemical (SEM-EDS and LA-ICP-MS) data for an exceptionally well-preserved orthopyroxene megacryst juxtaposed against granular harzburgite. Garnet lamellae within the megacryst show crystallographic continuity and have a strong fabric relative to the host orthopyroxene, strongly indicating that the megacryst formed by exsolution. Garnet lamellae are sub-calcic Cr-pyropes with sinusoidal rare earth element patterns, while the orthopyroxene host is high-Mg enstatite; the reconstructed precursor is clinoestatite. The megacryst shows evidence for disintegrating into granular peridotite, and garnet and orthopyroxene within the granular peridotite are texturally and chemically identical to equivalent phases in the megacryst. Collectively, this evidence supports a common origin for the granular and exsolved portions of the sample. The compositions of the exsolved Cr pyrope and enstatite are typical of harzburgites and depleted lherzolites from the SCLM. Furthermore, garnet inclusions within orthopyroxene in several granular peridotites exhibit the same fabric as those in the exsolved megacryst. We hypothesise that clinoenstatite was a common phase in cratonic SCLM and that exsolution is the likely origin of many sub-calcic garnets in depleted peridotites.
DS201806-1226
2018
Hoare, M.Hoare, M.Bring on blockchain?Gems&Jewellery www.gem-a-com, Spring, pp. 38-39.Technologyblockchain
DS1992-0713
1992
Hoare, T.Hoare, T., Chaplin, R.The Lac de Gras diamonds discoveryCredit Lyonnais Laing, Promotional liturature, 26pNorthwest TerritoriesNews item, Dia Met
DS1995-0806
1995
Hoatson, D.Hoatson, D.New mineral discoveries in the East Kimberley - Norton intrusion, FrogHollow, Upper Panton RiverAgso Newsletter, No. 22, May pp. 9, 10, 11AustraliaMafic intrusions
DS1995-0807
1995
Hoatson, D.Hoatson, D., et al.Recent NGMA mapping highlights the metallogenic potential of the EastKimberley.Agso Newsletter, No. 22, May p. 1, 2.AustraliaMetallogeny Kimberley area, Diamonds -brief mention
DS1995-1414
1995
Hoatson, D.Page, R., Hoatson, D.high Pressure precision geochronology of Paleoproterozoic layered mafic-ultramafic intrusions in East KimberleyAgso Newsletter, No. 22, May pp. 7, 8AustraliaLayered complexes, Geochronology
DS1996-1443
1996
Hoatson, D.Trudum A., Hoatson, D.Depths of emplacement of Precambrian layered intrusions in the EastKimberleyAgso Research Newsletter, No. 25, Nov. pp. 10, 11, 12AustraliaLayered intrusions, Geothermometry
DS1990-0703
1990
Hoatson, D.M.Hoatson, D.M., Keays, R.R.Formation of platiniferous sulfide horizons by crystal fractionation and magma mixing in the Munni Munni layered intrusion, west Pilbara block, WesternAustraliaEconomic Geology, Vol. 84, No. 7, November pp. 1775-1804AustraliaAlkaline rocks -Ultramafics, Munni Munni intrusion
DS1991-1674
1991
Hoatson, D.M.Sun, S.S., Wallace, D.A., Hoatson, D.M., Glikson, A.V.Use of geochemistry as a guide to platinum group element potential of mafic ultramafic rocks- examples the West Pilbara block and Halls Creek Mobile Zone:Precambrian Research, Vol. 50, No. 102, April pp. 1-35AustraliaPlatinuM., Geochemistry - review
DS201412-0422
2014
Hoatson, D.M.Jaireth, S., Hoatson, D.M., Miezitis, Y.Geological setting and resources of the major rare-earth-element deposits in Australia.Ore Geology Reviews, Vol. 61, pp. 72-128.AustraliaREE in alkaline rocks
DS1970-0550
1972
Hobbitt, R.P.Kridelbaugh, S.J., Hobbitt, R.P., Kellogg, K., Larson, E.E.Petrologic and Paleomagnetic Implication of the Green Mountain Diatreme.Geological Society of America (GSA), Vol. 4, No. 6, P. 386, (abstract.).United States, Colorado, Rocky Mountains, VermontRelated Rocks
DS200712-0444
2007
Hobbs, B.Hobbs, B., Regenauer-Lieb, K., Ord, A.Thermodynamics of folding in the middle to lower crust.Geology, Vol. 35, 2, pp. 175-176.MantleTectonics
DS201312-0321
2013
Hobbs, B.Gorczyk, W., Hobbs, B., Gessner, K., Gerya, T.Intracratonic geodynamics.Gondwana Research, Vol. 24, 3, pp. 838-848.MantleCraton, compression, extension
DS1986-0302
1986
Hobbs, B.E.Green, H.W., Borch, R., Hobbs, B.E.The pressure dependence of creep in olivine: consequences formantleflowProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 244-246GlobalBlank
DS1999-0310
1999
Hobbs, H.Hobbs, H.Origin of the driftless area by subglacial drainage - a new hypothesisGsa Mickelson And Attig Glacial Processes, Special Paper 337, pp.93-102.Wisconsin, MidcontinentGeomorphology
DS1991-1182
1991
Hobbs, H.C.Mooers, H.D., Hobbs, H.C., Gilbertson, J.P.Correlation of Late Wisconsin ice margins in MinnesotaGeological Society of America, Abstract Volume, Vol. 23, No. 3, March p. 50MinnesotaGeomorphology, Glacial
DS200712-1082
2007
Hobbs, H.C.Thorleifson, L.H., Harris, K.L., Hobbs, H.C., Jennings, C., Knaeble, Lively, Lusar, MeyerTill geochemical and indicator mineral reconnaissance of Minesota.Minnesota Geological Survey, Open File, 07-01, 512p. ( 7p.summary on line)United States, MinnesotaGeochemistry
DS1982-0279
1982
Hobbs, J.Hobbs, J.Detecting Diamond SimulantsIn: International Gemological Symposium Proceedings Volume, PP. 123-140.GlobalSynthetic, Kimberlite
DS1970-0703
1973
Hobbs, J.B.M.Gurney, J.J., Hobbs, J.B.M.Potassium, Thorium and Uranium in Some Kimberlites from South Africa.1st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 143-146.South AfricaMineralogy
DS1999-0690
1999
Hobbs, R.Snyder, D., Hobbs, R.The BIRPS Atlas II: a second decade of deep seismic reflection profilingGeological Society of London, CD-ROM approx. $ 165.00 United StatesEuropeCD-ROM data, Geophysics - seismics, Caledonia Orogen
DS1998-0875
1998
Hobbs, R.W.Line, C.E.R., Hobbs, R.W., Snyder, D.B.Estimates of upper crustal heterogeneity in the Baltic Shield from seismic scattering and borehole logs.Tectonophysics, Vol. 286, No. 1-4, Mar. 10, pp. 171-184.Baltic Shield, Sweden, Norway, FinlandGeophysics - seismic
DS200712-0898
2006
Hobbs, R.W.Rodger, M., Watts, A.B., Greenroyd, C.J., Peirce, C., Hobbs, R.W.Evidence for unusually thin oceanic crust and strong mantle beneath the Amazon Fan.Geology, Vol. 34, 12, pp. 1081-1084.South AmericaGeophysics - seismics
DS1860-0847
1894
Hobbs, W.H.Hobbs, W.H.On a Recent Diamond Find in Wisconsin and on the Probable Source of This and Other Wisconsin Diamonds.American Geologist, Vol. 14, PP. 31-35.United States, Wisconsin, CanadaDiamond Occurrence
DS1860-0890
1895
Hobbs, W.H.Hobbs, W.H.A Contribution to the Mineralogy of WisconsinUniversity Wisconsin Science Series Bulletin., Vol. 1, No. 4, PP. 109-156. ALSO: ZEITSCHRFT. KYST. Vol. 25United States, WisconsinMineralogy
DS1860-0940
1896
Hobbs, W.H.Hobbs, W.H.Diamanten von WisconsinNeues Jahrbuch fnr Mineralogie, BD. 2. PP. 249-251.United States, WisconsinDiamond Occurrence
DS1860-1086
1899
Hobbs, W.H.Hobbs, W.H.Emigrant Diamonds in America. #1 Eagle, Oregon, Saukville, MilfordPopular Science Monthly, Vol. 56, PP. 73-83.United States, CanadaDiamond Occurrence
DS1860-1087
1899
Hobbs, W.H.Hobbs, W.H.The Diamond Field of the Great LakesJournal of Geology, Vol. 7, PP. 375-388. ALSO: ZEITSCHRFT PRAKT. GEOL. Vol. 8, PUnited States, Great Lakes, CanadaGeology
DS1860-1088
1899
Hobbs, W.H.Hobbs, W.H.Diamond Fields of the Great Lakes. #1Milwaukee Sunday Sentinel, JUNE 11TH. ALSO: MINNEAPOLIS TRIBUNE AUGUST 13TH.; BROOKLYNUnited States, Great Lakes, WisconsinDiamond Occurrence
DS1900-0060
1901
Hobbs, W.H.Hobbs, W.H.Diamondiferous Deposits of the United StatesThe Mineral Industry During 1900, PP. 301-304.United States, Appalachia, West Coast, Great Lakes, Montana, Rocky MountainsReview
DS1900-0061
1901
Hobbs, W.H.Hobbs, W.H.Diamantiferous Deposits in the United StatesThe Mineral Industry, Vol. 9, PP. 301-304.United States, Great Lakes, Appalachia, West Coast, Virginia, South CarolinaDiamond Occurrence
DS1900-0119
1902
Hobbs, W.H.Hobbs, W.H.Emigrant Diamonds in America. #2Smithsonian Institute Annual Report, PP. 359-366.United States, Appalachia, Great Lakes, CanadaGlacial, Diamonds Notable, Eagle, Oregon, Saukville, Milford
DS1950-0105
1952
Hobbs, W.H.Hobbs, W.H.An Explorer Scientist's PilgrimageAnn Arbor: J.w. Edwards, PP. 29-32.United States, Great Lakes, WisconsinDiamond, History, Autobiography
DS1950-0137
1953
Hobbs, W.H.Hobbs, W.H.The Diamond Fields of the Great LakesPrecambrian., Vol. 26, No. 3, PP. 16-20.United States, Wisconsin, Great Lakes, CanadaDiamond Occurrences, Origin
DS1993-1428
1993
Hobden, B.J.Sewell, R.J., Hobden, B.J., Weaver, S.D.Mafic and ultramafic mantle and deep crustal xenoliths from BanksPeninsula, South Island, New Zealand.New Zealand Journal of Geology and Geophysics, Vol. 36, No. 2, pp. 223-231.GlobalMantle xenoliths
DS2003-0186
2003
Hobson, E.Burgess, R., Harrison, D., Hobson, E., Harris, J.W.Noble gas and halogen constraints on the origin of volatile rich fluids in Canadian8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractNorthwest TerritoriesDiamonds - mineralogy, Deposit - Panda
DS200912-0087
2009
Hobson, E.Burgess, R., Cartigny, P., Harrison, D., Hobson, E., Harris, J.Volatile composition of Micro inclusions in diamonds from the PAnd a kimberlite, Canada: implications for chemical and isotopic heterogeneity in the mantle.Geochimica et Cosmochimica Acta, Vol. 73, 6, pp. 1779-1794.Canada, Northwest TerritoriesDeposit - Panda
DS2001-0482
2001
Hoch, M.Hoch, M., Rehkamper, M., Tobsachall, H.J.Strontium, neodymium, lead, Oxygen isotopes of minettes from Schirmacher Oasis: a case of mantle me tasomatism involving subduction....Journal of Petrology, Vol. 42, No. 7, July pp. 1387-1400.GlobalContinental material - subduction, Minettes
DS201212-0755
2012
Hochard, C.Verad, C., Hochard, C., Stampfil, G.Non-random distribution of euler poles: is plate tectonics subject to rotational effects?Terra Nova, in press availableMantleTectonics
DS201907-1556
2019
Hochberg, Y.Kurinsky, N., Yu, C., Hochberg, Y., Cabrera, B.Diamond detectors for direct detection of sub-GeV dark matter.Physical Review, Vol. 99, June 15, 123005Spacediamond morphology

Abstract: We propose to use high-purity lab-grown diamond for the detection of sub-GeV dark matter. Diamond targets can be sensitive to both nuclear and electron recoils from dark matter scattering in the MeV and above mass range, as well as to absorption processes of dark matter with masses between sub-eV to 10's of eV. Compared to other proposed semiconducting targets such as germanium and silicon, diamond detectors can probe lower dark matter masses via nuclear recoils due to the lightness of the carbon nucleus. The expected reach for electron recoils is comparable to that of germanium and silicon, with the advantage that dark counts are expected to be under better control. Via absorption processes, unconstrained QCD axion parameter space can be successfully probed in diamond for masses of order 10 eV, further demonstrating the power of our approach.
DS1991-1733
1991
Hochela, M.F.Jr.Tingle, T.N., Hochela, M.F.Jr.Organic matter in basalts and mantle xenolithsGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 19GlobalMagma, Bioorganics
DS1990-1467
1990
Hochella, M.F.Tingle, T.N., Hochella, M.F., Becker, C.H.Reduced carbon in basalts and mantle xenolithsEos, Vol. 71, No. 17, April 24, p. 644 Abstract onlyGlobalBasalts, mantle xenoliths, Geochronology -carbon
DS2002-0727
2002
Hochella, M.F.Hochella, M.F.Sustaining earth: thoughts on the present and future roles of mineralogy in environment science.Mineralogical magazine, Vol. 66,5, pp. 627-52.EarthEnvironmental, History
DS201711-2502
2017
Hochella, M.F.Brown, G.E., Hochella, M.F., Calas, G.Improving mitigation of the long term legacy of mining activities: nano and molecular level concepts and methods.Elements, Vol. 13, pp. 325-330.Globalresources

Abstract: Mining activities over several millennia have resulted in a legacy of environmental contamination that must be mitigated to minimize ecosystem damage and human health impacts. Designing effective remediation strategies for mining and processing wastes requires knowledge of nano- and molecular-scale speciation of contaminants. Here, we discuss how modern nano- and molecular-level concepts and methods can be used to improve risk assessment and future management of contaminants that result from mining activities, and we illustrate this approach using relevant case studies.
DS1991-1734
1991
Hochella, M.F.Jr.Tingle, T.N., Hochella, M.F.Jr.Reduced carbonaceous matter in basalts and mantle xenolithsProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 432-434Hawaii, Arizona, Mid-Atlantic Ridge, South Africa, MontanaOrganic matter, Geochronology -isotopes
DS1991-1735
1991
Hochella, M.F.Jr.Tingle, T.N., Mathez, E.A., Hochella, M.F.Jr.Carbonaceous matter in peridotites and basalts studied by XPS, SALI, SOURCE[ Geochimica et Cosmochimica ActaGeochimica et Cosmochimica Acta, Vol. 55, pp. 1345-1352South AfricaKimberlite -Jagersfontein, Spectroscopy
DS200912-0306
2008
Hochella, M.F.jr.Hochella, M.F.jr.Nanogeoscience: from origins to cutting esge applications.Elements, Vol. 4, no. 6, December pp. 373-379.TechnologyNanogeoscience
DS1994-0776
1994
Hochstaedter, A.G.Hochstaedter, A.G., et al.On the tectonic significance of arc volcanism in northern KamchatkaJournal of Geology, Vol. 103, No. 6, Nov. pp. 639-654.Russia, KamchatkaTectonics, Okhotsk Block
DS1995-0808
1995
Hock, J.D.Hock, J.D., Seitz, H.M.Continental mafic dyke swarms as tectonic indicators: an example from the Vestfold Hills, East Antarctica.Precambrian Research, Vol. 75, No. 3-4 Dec. 1, pp. 121-140.AntarcticaDike, Tectonics
DS200612-0349
2006
Hock, V.Downes, H., Cvetkovic, V., Hock, V., Prelevic, D., Lazarov, M.Refertilization of highly depleted lithospheric mantle ( Balkan Peninsula, SE Europe): evidence from peridotite xenoliths.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.EuropeGeochemistry
DS1990-0704
1990
Hocker, P.M.Hocker, P.M.No mine is an island. the mining industry amid risingenvironmentalexpectationsColorado School of Mines, Department of Mineral Economics, Working Paper No. 90-5, 23pUnited StatesEconomics, Environmental issues
DS1970-0716
1973
Hocking, A.Hocking, A.Diamonds... Pride of South Africa No. 2Cape Town: Purnell, 24P. REPRINT 1982 JOHANNESBURG: CENTAUR.South AfricaHistory, Kimberley
DS1970-0717
1973
Hocking, A.Hocking, A.Oppenheimer and SonNew York: Mcgraw-hill, 526P., ILLUS.South AfricaKimberley, Janlib, Biography
DS1998-0624
1998
Hocking, R.M.Hocking, R.M., Preston, W.A.Western Australia: Phanerozoic geology and mineral resourcesAgso, Vol. 17, No. 3, pp. 245-260.Australia, Western AustraliaBasin development, Paleozoic history, Diamonds mentioned pp. 254-6.
DS1970-0718
1973
Hocq, M.Hocq, M.Rapport preliminaire sur la geologie de la region du lac Michaux, territoire de Mistassini.Quebec Department of Mines, DP 206, 20p.QuebecGeology
DS1975-0294
1976
Hocq, M.Hocq, M.La Geologie de la Region du Lac Michaux, Territoire de MistassiniQuebec Department of Mines, DPV 435, 94p.QuebecGeology
DS1985-0290
1985
Hocq, M.Hocq, M.Geologie de la Region des Lacs Campan et CadieuxQuebec Department of Mines, ET 83-05, 178p.QuebecGeology
DS1989-0645
1989
Hocq, M.Hocq, M.Carte lithotectoniques des sous provinces de l'Abitibi et du PontiacQuebec Department of Mines, Map 2092a, b, c.QuebecMap - geology
DS1994-0777
1994
Hocq, M.Hocq, M.La Province du SuperieurQuebec Department of Mines, MM 94-01, pp. 7-20.QuebecTectonics, geology
DS2000-0535
2000
Hoda, S.Q.Krishnamuthry, P., Hoda, S.Q., Sinha, R.P., BanerjeeEconomic aspects of carbonatites in IndiaJournal of Asian Earth Science, Vol. 18, No.2, Apr. pp.229-35.IndiaCarbonatite, Economics
DS201605-0831
2016
Hodder, A.Du Toit, D., Meno, T., Telema, E., Boshoff, P., Hodder, A.Survey systems adopted to improve safety and efficiency at Finsch diamond mine.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 187-196.Africa, South AfricaDeposit - Finsch
DS1989-0083
1989
Hodder, R.W.Barron, K.M., Duke, N.A., Hodder, R.W.A high level Archean alkaline carbonatite complex,Springpole Lake NorthWest OntarioGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A72. (abstract.)OntarioCarbonatite
DS1989-0084
1989
Hodder, R.W.Barron, K.M., Duke, N.A., Hodder, R.W.Petrology of the Springpole Lake alkalic volcanic complexOntario Geological Survey miscellaneous Paper, No. 143, pp. 133-145OntarioAlkaline rocks, Springpole Lake complex
DS1991-0425
1991
Hodder, R.W.Edwards, G.R., Hodder, R.W.A semi-quantitative model for fractionation of rhyolite from rhyodacite in a compositionally altered Archean volcanic complex, Superior Province, CanadaPrecambrian Research, Vol. 50, No. 1-2. April pp. 49-67OntarioGeochronology, Geochemistry, petrography
DS200512-0161
2004
Hodder, S.Chartier, T., Hodder, S.Update on the Knife Lake kimberlite and Inulik diamond property, Coronation diamond district, Nunavut. Rhonda Corporation.32nd Yellowknife Geoscience Forum, Nov. 16-18, p.14. (talk)Canada, NunavutCompany overview
DS2003-0592
2003
Hodder, S.L.Hodder, S.L.Petrography of the McLean kimberlite, Lake Timiskaming, Ontario8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractOntarioDeposit - McLean Lake
DS200412-0839
2003
Hodder, S.L.Hodder, S.L.Petrography of the McLean kimberlite, Lake Timiskaming, Ontario.8 IKC Program, Session 7, POSTER abstractCanada, OntarioKimberlite petrogenesis Deposit - McLean Lake
DS202001-0012
2019
Hodder, T.Gauthier, M.S., Hodder, T., Ross, M., Kelley, S.E. Rochester, A., McCausland< P. The subglacial mosaic of the Laurentide ice sheet; a study of the interior region of southwestern Hudson Bay.Quaternary Science Reviews, Vol. 214, pp. 1-27.Canada, Manitobageomorphology

Abstract: Reconstructions of past ice-flow provide useful insights into the long-term behaviour of past ice sheets and help to understand how glaciated landscapes are shaped. Here, we present reconstruction of a 10-phase ice-flow history from southwestern Hudson Bay in northeastern Manitoba (Canada), a dynamic region situated between two major ice dispersal centres of the Laurentide Ice Sheet. We utilize a diverse geologic dataset including 1900 field-based erosional indicators, 12 streamlined-landform flowsets, esker and meltwater corridor orientations, 103 till-fabrics analyses, and 1344 till-clast lithology counts. Our reconstruction suggests that both pre-MIS 2 and MIS 2 glaciations followed similar growth patterns, where ice advanced into study area from ice centered to the east (probably in northern Quebec), followed by a switch in ice-flow direction indicating flow from the Keewatin ice centre to the northwest and north. The cause for this switch in ice-flow orientation is uncertain, but the youngest switch may relate to retreat of ice during MIS 3 that then left space for Keewatin-sourced ice to advance over the study area. While modelling experiments indicate widespread cold-based conditions in the study area during the last glacial cycle, uniformly relict landscapes are not common. Instead, the glaciated landscape is palimpsest and commonly fragmented, forming a subglacial bed mosaic of erosional and depositional assemblages that record both shifting ice-flow direction through time and shifting subglacial conditions. Each assemblage formed, or modified, during times of dynamic (warm-based) ice, and later preserved under conditions below or close to the pressure melting point (slow and sluggish, or cold-based).
DS202001-0015
2018
Hodder, T. KelleyHodder, T. Kelley, S.E.Kimberlite indicator minerals and clast lithology composition of till, Kaskattama region northeastern Manitoba (parts of NTS 53N, O, 54 B,C.)Manitoba Report, GS2018-13 pdf 17p. Canada, Manitobageochemistry

Abstract: Canada exhibits many of the challenges involved with exploring for coloured stones in countries with very low population densities, temperate-to-arctic climates and a lack of infrastructure hindering access to most prospective areas. Despite this, a number of discoveries have occurred, mainly during the past two decades. These include emeralds from Northwest Territories (1997) and Yukon (1998); sapphire (2002) and spinel (from 1982)—including cobalt-blue stones—from Baffin Island in Nunavut; and ruby and pink sapphire (2002) from British Columbia. Such discoveries can be assisted by undertaking scientific research into gem formation, as well as by applying exploration criteria developed elsewhere to uncharted territory. Future exploration in Canada and other countries facing similar challenges will likely benefit from additional geological studies to identify prospective areas and features; innovative means of transportation, such as boats instead of aircraft; drones for exploring rugged terrain; hyperspectral imaging for mineral sensing; surveying with UV lamps to identify minerals associated with gem mineralisation; and careful prospecting (including field mapping and collecting heavy mineral concentrates) by experienced individuals. Quaternary geology fieldwork was conducted at a reconnaissance-scale in the Kaskattama highland area to document the Quaternary stratigraphy and till composition. The diamond potential of this region was investigated using kimberlite-indicator-mineral (KIM) counts from till samples. Indicator mineral results are the focus of this report and are combined with ice-flow and till-clast-lithology data to provide a context to interpret provenance. Kimberlite-indicator minerals were recovered from glacial sediments (till) in the Kaskattama highland area and KIM counts are elevated relative to data from the surrounding area. The lowest KIM counts were from till with a high Hudson Bay Basin (carbonatedominated) and low undifferentiated greenstone and greywacke (UGG) provenance signature. The highest KIM counts are associated with till samples that have a relatively elevated UGG or elevated granitoid provenance signature. Till samples with relatively elevated UGG concentration have an interpreted east or southeast provenance, which is supported by ice-flow data and the recovery of distinct east-sourced erratics. Till samples with a relatively elevated granitoid clast concentration have a correlation with the southwest- trending Hayes streamlined-landform flowset. Considering the likely provenance for granitoid clasts is to the northwest, the presence of relatively high concentrations of granitoid clasts in the Hayes flowset could be indicative of a higher inheritance from previous ice-flow events or a palimpsest dispersal pattern. Interpretation of till-composition and ice-flow data has indicated there are likely multiple sources for the KIMs recovered during this study. Detailed work is recommended to clarify local-scale dispersal patterns.
DS201312-0442
2013
Hodder, T.J.Johnson, C.L., Ross, M., Grunsky, E., Hodder, T.J.Fingerprinting glacial processes for diamond exploration on Baffin Island.Geoscience Forum 40 NWT, Poster abstract only p. 62Canada, Nunavut, Baffin IslandGeomorphology
DS201706-1080
2017
Hodder, T.J.Hodder, T.J., Kelley, S.E., Trommelen, M.S., Ross, M., Rinne, M.L.The Kaskattama highland: till composition and indications of a new Precambrian In lier in the Hudson Bay Lowland?GAC annual meeting, 1p. AbstractCanada, Manitobageochemistry
DS201706-1108
2017
Hodder, T.J.Trommelen, M.S., Gauthier, M., Kelly, S.E., Hodder, T.J., Wang, Y., Ross, M.Till composition inheritance and overprinting in the Hudson Bay Lowland and across the Precambrian shield.GAC annual meeting, 1p. AbstractCanada, Manitobageochemistry

Abstract: The goal of this work is to determine the effect of multiple glaciations on till composition, in a zone of transition from a multi-till stratigraphy within the Hudson Bay Lowland (HBL) to a single till stratigraphy over the Precambrian shield. The study area, in NE Manitoba, has access to numerous sections that expose multiple tills, in addition to interglacial and postglacial sediments. Sequences of thick till are not easily separated into different units, despite previous field attempts to define four named tills. The compositional transition to thin till overlying the Precambrian Shield in the west is also not well understood. Yet, the two different settings were affected by the same 3+ glacial cycles. The wide range in eastern- and/or northeastern-sourced calcareous clast concentrations, and ‘locally’-sourced shield clast concentrations, combined with variable concentrations of northern-sourced clasts, suggests that the tills of northeastern Manitoba are ‘provenance’ hybrids. Local tills result from the net effect of multiple glacial processes that underwent spatiotemporal variability. Mixed provenance applies not only to surface tills, but to the subsurface tills as well. Preliminary results suggest that carbonate transport across the shield was continuous throughout several glacial cycles, but the bulk of transport likely occurred prior to the most recent glacial cycle. Current work has established a northern-Manitoba ice-flow history using the erosional and depositional record, which encompasses 5 to 7 phases. This new compilation is used in conjunction with ‘till-clast’ stratigraphy and ‘till-geochemistry’ stratigraphy, to identify a new provenance framework for tills in northeastern Manitoba.
DS201711-2517
2017
Hodder, T.J.Hodder, T.J.Kimberlite indicator mineral results derived from glacial sediments ( till) in the Southern Indian Lake area of north central Manitoba ( parts of NTS 64B15, 64G1,2,7,8).Manitoba Geological Survey, Open File OF2017-2, 13p. PdfCanada, Manitobageochemistry
DS1992-1265
1992
Hodeau, J-L.Regueiro, M.N., Monceau, P., Hodeau, J-L.Crushing C60 to diamond at room temperatureNature, Vol. 355, No. 6357, January 16, pp. 237-238GlobalExperimental petrology, Carbon
DS1983-0308
1983
Hodge, C.J.Hodge, C.J.Structure, Petrology, and Geochemistry of the Aultman Kimberlite Diatremes, Albany County, Wyoming.Msc. Thesis, Colorado State University, United States, State Line, WyomingBlank
DS1983-0309
1983
Hodge, C.J.Hodge, C.J.Structure, petrology and geochemistry of the Aultman kimberlite Albany County, WyomingMsc. Colorado State Univ, WyomingKimberlite Diatremes, Geochemistry
DS1982-0418
1982
Hodge, C.W.Mccallum, M.E., Coopersmith, H.G., Hodge, C.W.Mineralogical and Textural Genetic Classification of Kimberlites in Northern Colorado and Southern Wyoming, United States (us)Proceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 209, (abstract.).United States, Colorado, Wyoming, State Line, Rocky MountainsBlank
DS1970-0601
1972
Hodge, D.S.Smithson, S.B., Hodge, D.S.Field Relations and Gravity Interpretation in the Laramie Anorthosite Complex.University WYOMING CONTRIB. TO GEOLOGY, Vol. 11, No. 2, PP. 43-59.United States, Wyoming, State Line, Rocky MountainsBlank
DS201212-0303
2012
Hodge, K.F.Hodge, K.F., Carazzo, G., Jellinek, A.M.Experimental constraints on the deformation and breakup of injected magma.Earth and Planetary Science Letters, Vol. 325-326, pp. 52-62.MantleMagmatism
DS1994-0778
1994
Hodge, P.Hodge, P.Meteorite craters and impact structures of the earthCambridge University of Press Book, 125p.United States, Canada, Latin America, Australia, Europe, AfricaMeteorites, Impact craters
DS1994-0779
1994
Hodge, P.Hodge, P.Meteorite craters and impact structures of the earthCambridge University of Press, 130pUnited States, Canada, Latin America, Australia, South AfricaMeteorite craters, Book -table of contents
DS1970-0730
1973
Hodgen, R.Joynt, R.H., Greenshields, R., Hodgen, R.Advances in Sea and Beach Diamond Mining TechniquesMining Engineering Journal of South Africa, Vol. No. APRIL, PP. 25-49.Southwest Africa, NamibiaSubmarine Diamond Placers, Marine Diamond Corporation, Sampling
DS1995-0809
1995
Hodges, C.A.Hodges, C.A.Mineral resources, environment issues and land useScience, Vol. 268, June 2, pp. 1305-1312United StatesLegal, Land use
DS1994-1500
1994
Hodges, K.V.Ruppel, C., Hodges, K.V.Pressure temperature time paths from two dimensional thermal models:prograde, retrograde and inverted metamorphismTectonics, Vol. 13, No. 1, Feb. pp. 17-44.Mantlemetamorphism
DS200612-0400
2006
Hodges, K.V.Flowers, R.M., Mahan, K.H., Bowring, S.A., Williams, M.L., Pringle, M.S., Hodges, K.V.Multistage exhumation and juxaposition of lower continental crust in the western Canadian Shield: linking high resolution U Pb and 40 Ar / 39 Ar thermochronometry with pressure temperature deformation paths.Tectonics, Vol. 25, 4, TC4003, 20p.Canada, Alberta, Saskatchewan, Northwest TerritoriesGeothermometry, thermocrhonmetry, deformation P T
DS1970-0535
1972
Hodges, P.A.Hodges, P.A.Supplement to Feasibility Study of the Letseng la Terai Project.Rio Tinto Exploration (pty) Ltd., 50P.LesothoEconomics, Evaluation, Sampling
DS1998-0625
1998
Hodgetts, D.Hodgetts, D., Egan, S.S., Williams, G.D.Flexural modelling of continental lithosphere deformation: a comparison of2D and 3D techniques.Tectonophysics, Vol. 294, No. 1-2, Aug. 30, pp. 1-20.MantleLithosphere - model
DS1991-0721
1991
Hodgins, B.L.Hodgins, B.L., Halways, L.E.Rotary blasthole drills: future trendsSkillings Mining Review, Vol. 80, No. 15, April 13, pp. 4-7GlobalDrilling, Rotary blastholes -open pit Mines
DS1989-0646
1989
Hodgkinson, A.Hodgkinson, A.Visual optics. (Distinguishing between diamond and various simulants)Australia Gemologist, Vol. 17, No. 4, pp. 137-138GlobalDiamond morphology, Optics
DS1989-0647
1989
Hodgkinson, A.Hodgkinson, A.Visual optics- cubic zirconiaThe Australian Gemologist, November pp. 137-138GlobalVisual optics, Zirconia-diamond
DS1998-0626
1998
Hodgkinson, A.Hodgkinson, A.Diamond distinction from synthetic moissanite - in the darkCanadian Gemologist, XIX, No. 2, Summer pp. 59-60.GlobalDiamond synthesis, Moissanite
DS1998-0256
1998
HodgsonClark, 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
DS1960-0964
1968
Hodgson, C.J.Hodgson, C.J.Montregian Dyke RocksPh.d. Thesis, Mcgill University, 168P.Canada, QuebecDiatreme Breccias
DS1989-1236
1989
Hodgson, C.J.Powell, W.G., Hodgson, C.J., Hanes, J.A.The expression of the Larder Lake Break in the Matachewan areaOntario Geological Survey miscellaneous Paper, No. 143, pp. 125-132OntarioTectonics, Fault
DS1992-1661
1992
Hodgson, C.J.Whiting, B.H., Mason, R., Hodgson, C.J.Giant ore deposits #1Department of Geological Sciences, Queen's University, 550pGlobalDiamond, nickel, copper, platinum, Porphyry copper, molybdenum, sulphide
DS1993-1725
1993
Hodgson, C.J.Whiting, B., Hodgson, C.J., Mason, R.Giant Ore Deposits #2Society of Economic Geology Special Publication, No. 2, 404pGlobalBook -table of contents, Deposits -diamonds, nickel, gold, copper, moly, MVS
DS1995-1514
1995
Hodgson, C.J.Powell, W.G., Hodgson, C.J., Hanes, J.A., Carmichael40Ar/39 Ar geochron. evidence for multiple post metamorphic hydrothermal events focussed along faultsCanadian Journal of Earth Sciences, Vol. 32, No. 6, June pp. 768-786Ontario, QuebecGeochronology, Argon, Abitibi greenstone belt
DS1992-0714
1992
Hodgson, D.A.Hodgson, D.A.Quaternary geology of Western Melville Island, Northwest TerritoriesGeological Survey Canada Paper, No. 89-21, 35p. $ 17.90Northwest TerritoriesQuaternary
DS1992-0715
1992
Hodgson, D.A.Hodgson, D.A.Surficial geology of Western Melville Island, Northwest TerritoriesGeological Survey Canada Map, Map No. 1753A included in Paper 89-21. 1: 250, 000Northwest TerritoriesQuaternary, Map
DS200812-0973
2007
Hodgson, D.A.Ross, M., Utting, D.J., Hodgson, D.A., James, D.T.Ice flow and dispersal patterns on Southampton Island Nunavut: a preliminary Assessment. ( KIMs)35th. Yellowknife Geoscience Forum, Abstracts only p. 52.Canada, NunavutGeochemistry - samples
DS1975-0530
1977
Hodgson, D.L.Hodgson, D.L.Mining the Beach for Diamonds at Consolidated Diamond Mines of Southwest Africa Limited.Engineering and Mining Journal, Vol. 178, No. 6, PP. 141-151.Southwest Africa, NamibiaDiamond Mining Recovery, Littoral Diamond Placers
DS201803-0466
2018
Hodgson, D.M.Nakashole, A.N., Hodgson, D.M., Chapman, R.J., Morgan, D.J., Jacob, R.J.Long term controls on continental scale bedrock river terrace deposition from integrated clast and heavy mineral assemblage analysis: an example from the Lower Orange River, Namibia. ( Diamondiferous gravel terraces)Sedimentary Geology, Vol. 364, pp. 103-120.Africa, Namibiadeposit - Orange River

Abstract: Establishing relationships between the long-term landscape evolution of drainage basins and the fill of sedimentary basins benefits from analysis of bedrock river terrace deposits. These fragmented detrital archives help to constrain changes in river system character and provenance during sediment transfer from continents (source) to oceans (sink). Thick diamondiferous gravel terrace deposits along the lower Orange River, southern Namibia, provide a rare opportunity to investigate controls on the incision history of a continental-scale bedrock river. Clast assemblage and heavy mineral data from seven localities permit detailed characterisation of the lower Orange River gravel terrace deposits. Two distinct fining-upward gravel terrace deposits are recognised, primarily based on mapped stratigraphic relationships (cross-cutting relationships) and strath and terrace top elevations, and secondarily on the proportion of exotic clasts, referred to as Proto Orange River deposits and Meso Orange River deposits. The older early to middle Miocene Proto Orange River gravels are thick (up to 50 m) and characterised by a dominance of Karoo Supergroup shale and sandstone clasts, whereas the younger Plio-Pleistocene Meso Orange River gravels (6-23 m thick) are characterised by more banded iron formation clasts. Mapping of the downstepping terraces indicates that the Proto gravels were deposited by a higher sinuosity river, and are strongly discordant to the modern Orange River course, whereas the Meso deposits were deposited by a lower sinuosity river. The heavy minerals present in both units comprise magnetite, garnet, amphibole, epidote and ilmenite, with rare titanite and zircon grains. The concentration of amphibole-epidote in the heavy minerals fraction increases from the Proto to the Meso deposits. The decrease in incision depths, recorded by deposit thicknesses above strath terraces, and the differences in clast character (size and roundness) and type between the two units, are ascribed to a more powerful river system during Proto-Orange River time, rather than reworking of older deposits, changes in provenance or climatic variations. In addition, from Proto- to Meso-Orange River times there was an increase in the proportion of sediments supplied from local bedrock sources, including amphibole-epidote in the heavy mineral assemblages derived from the Namaqua Metamorphic Complex. This integrated study demonstrates that clast assemblages are not a proxy for the character of the matrix, and vice versa, because they are influenced by the interplay of different controls. Therefore, an integrated approach is needed to improve prediction of placer mineral deposits in river gravels, and their distribution in coeval deposits downstream.
DS1960-0057
1960
Hodgson, H.F.Hodgson, H.F., Sewel, E.J.B.Mining Practice at the Premier MineSouth African Institute of Mining and Metallurgy. Journal, Vol. 61, SEPT. PP. 61-89.South AfricaMining Methods, Recovery, Diamond, Kimberlite Pipes
DS1960-0315
1963
Hodgson, H.F.Adamson, R.J., Hodgson, H.F.The Re-treatment Plant at Premier Diamond MineSouth African Institute of Mining and Metallurgy. Journal, Vol. 64, SEPT. PP. 45-67.South AfricaDiamond Mining Recovery, Kimberlite Pipes
DS1981-0216
1981
Hodgson, M.Hodgson, M.Determination of Olivine and Serpentine in Kimberlite by X-ray Diffraction.Ph.d. Thesis University London., 449P.South AfricaWesselton, Analytical Standards, Sampling
DS1984-0356
1984
Hodgson, M.Hodgson, M., Dudeney, A.W.L.Determination of Olivine and Serpentine in Kimberlites by X-ray Diffraction.Analyst., Vol. 109, No. 9, P. 1129. (abstract.).GlobalMineralogy
DS1984-0357
1984
Hodgson, M.Hodgson, M., Dudeney, A.W.L.Determination of Olivine and Serpentine in Kimberlite by X Ray Diffraction.Analyst., Vol. 109, No. 9, SEPTEMBER PP. 1129-1133.South AfricaMineralogy, Mineral Chemistry, Wesselton, Analytical Standards
DS1988-0309
1988
Hodgson, M.Hodgson, M., Dudeney, A.W.L.Hydrothermal alteration of kimberlite in acid media with aluminum ionadditionsTransactions of the Institute of Mining and Metallurgy (IMM), Pt. C Vol. 97, March pp. C1-C14GlobalMineral processing, Kimberlite
DS1988-0251
1988
Hodgson, N.Gerlach, D.C., Cliff, R.A., Davies, G.R., Norry, M., Hodgson, N.Magma sources of the Cape Verdes Archipelago: isotopic and trace elementconstraintsGeochimica et Cosmochimica Acta, Vol. 52, No. 12, pp. 2979-2992GlobalBasanite, Carbonatite, Melilitite, Rare earths
DS200612-0734
2005
Hodrireva, V.A.Korpechkov, D.I., Hodrireva, V.A., Savvaitov, A.S.Minerals of the kimberlitic assemblage in terrigenous sediments of Latvia and perspectives of its diamond potential.Lithology and Mineral Resources, Vol. 40, 8, Nov. pp. 528-536.Europe, LatviaGeochemistry, KMA, Upper Devonian
DS1991-0498
1991
Hoefer, H.Foley, S.F., Hoefer, H., Brey, G.P.The stability of priderite, lindsleyite-mathiasite andyimengite-hawthornite under lower continental lithosphere conditions:experiments at 35 to 50 KbarProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 106-108South Africa, Russia, AustraliaMicroprobe analyses, LIMA.
DS201810-2321
2018
Hoefer, H.Ghobadi, M., Gerdes, A., Kogarko, L., Hoefer, H., Brey, G.In situ LA-ICPMS isotopic and geochronological studies on carbonatites and phoscorites from the Guli Massif, Maymecha-Kotuy, polar Siberia.Geochemistry International, Vol. 56, 8, pp. 766-783.Russia, Siberiacarbonatite

Abstract: In this study we present a fresh isotopic data, as well as U-Pb ages from different REE-minerals in carbonatites and phoscorites of Guli massif using in situ LA-ICPMS technique. The analyses were conducted on apatites and perovskites from calcio-carbonatite and phoscorite units, as well as on pyrochlores and baddeleyites from the carbonatites. The 87Sr/86Sr ratios obtained from apatites and perovskites from the phoscorites are 0.70308-0.70314 and 0.70306-0.70313, respectively; and 0.70310-0.70325 and 0.70314-0.70327, for the pyrochlores and apatites from the carbonatites, respectively. Furthermore, the in situ laser ablation analyses of apatites and perovskites from the phoscorite yield eNd from 3.6 (±1) to 5.1 (±0.5) and from 3.8 (±0.5) to 4.9 (±0.5), respectively; eNd of apatites, perovskites and pyrochlores from carbonatite ranges from 3.2 (±0.7) to 4.9 (±0.9), 3.9 (±0.6) to 4.5 (±0.8) and 3.2 (±0.4) to 4.4 (±0.8), respectively. Laser ablation analyses of baddeleyites yielded an eHf(t)d of +8.5 (± 0.18); prior to this study Hf isotopic characteristic of Guli massif was not known. Our new in situ eNd, 87Sr/86Sr and eHf data on minerals in the Guli carbonatites imply a depleted source with a long time integrated high Lu/Hf, Sm/Nd, Sr/Rb ratios. In situ U-Pb age determination was performed on perovskites from the carbonatites and phoscorites and also on pyrochlores and baddeleyites from carbonatites. The co-existing pyrochlores, perovskites and baddeleyites in carbonatites yielded ages of 252.3 ± 1.9, 252.5 ± 1.5 and 250.8 ± 1.4 Ma, respectively. The perovskites from the phoscorites yielded an age of 253.8 ± 1.9 Ma. The obtained age for Guli carbonatites and phoscorites lies within the range of ages previously reported for the Siberian Flood Basalts and suggest essentially synchronous emplacement with the Permian-Triassic boundary.
DS200412-0840
2003
Hoefer, H.E.Hoefer, H.E., Brey, G.P., Woodland, A.B.Iron oxidation state of mantle minerals determined from L emission spectra by the electron microprobe.8 IKC Program, Session 6, POSTER abstractTechnologyMantle petrology
DS201212-0424
2012
Hoefer, H.E.Luchs, T., Brey, G.P., Gerdes, A., Hoefer, H.E.Lu-Hf and Sm-Nd geochronology and geothermobarmetry of the lithospheric mantle beneath the Gibeon kimberlite field, Namibia.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, NamibiaDeposit - Gibeon
DS201212-0652
2012
Hoefer, H.E.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Ultra depleted eclogites: residues of TTG melting.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, South AfricaDeposit - Bellsbank
DS201312-0820
2013
Hoefer, H.E.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Geochronological and geochemical constraints on the formation and evolution of the mantle beneath the Kaapvaal craton: Lu Hf and Sm Nd systematics of subcalcic garnets from highly depleted peridotites.Geochimica et Cosmochimica Acta, Vol. 113, pp. 1-20.Africa, South AfricaDeposit - Roberst Victor, Lace
DS201312-0821
2013
Hoefer, H.E.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Simultaneous mantle metasomatism, diamond growth and crustal events in the Archean and Proterozoic of South Africa.Goldschmidt 2013, AbstractAfrica, South AfricaMetasomatism
DS201312-0824
2013
Hoefer, H.E.Sieber, M., Brey, G.P., Seitz, H-M., Gerdes, A., Hoefer, H.E.The age of eclogitisation underneath the Kaapvaal craton - a composite xenolith from Roberts Victor.Goldschmidt 2013, 1p. AbstractAfrica, South AfricaDeposit - Roberts Victor
DS201412-0822
2014
Hoefer, H.E.Shu, Q., Brey, G.P., Gerdes, A., Hoefer, H.E.Mantle eclogites and garnet pyroxenites - the meaning of two point isochrons, Sm-Nd and Lu-Hf closure temperatures and the cooling of the subcratonic mantle.Earth and Planetary Science Letters, Vol. 389, pp. 143-154.MantleGeochronology
DS201603-0420
2016
Hoefer, H.E.Shu, Q., Brey, G.P., Hoefer, H.E., Zhao, Z., Pearson, D.G.Kyanite/corundum eclogites from the Kaapvaal craton: subducted troctolites and layered gabbros from the Mid- to Early Archean.Contributions to Mineralogy and Petrology, Vol. 171, 11, 24p.Africa, South AfricaDeposit - Bellsbank

Abstract: An oceanic crustal origin is the commonly accepted paradigm for mantle-derived eclogites. However, the significance of the aluminous members of the eclogite suite, containing kyanite and corundum, has long been underrated and their role neglected in genetic models of cratonic evolution. Here, we present a geochemical and petrological study of a suite of kyanite- and corundum-bearing eclogites from the Bellsbank kimberlite, S. Africa, which originate from depths between 150 and 200 km. Although clearly of high-pressure provenance, these rocks had a low-pressure cumulative origin with plagioclase and olivine as major cumulate phases. This is shown by the very pronounced positive Eu anomalies, low REE abundances, and d 18O values lower than the Earth’s mantle. Many chemical features are identical to modern-day troctolitic cumulates including a light REE depletion akin to MORB, but there are also distinguishing features in that the eclogites are richer in Na, Fe, and Ni. Two of the eclogites have a minimum age of ~3.2 Ga, defined by the extremely unradiogenic 87Sr/86Sr (0.7007) in clinopyroxene. Phase equilibria indicate that the parent melts were formed by partial melting below an Archean volcanic center that generated (alkali-)picritic to high-alumina tholeiitic melts from a mantle whose oxygen fugacity was lower than today. Fractional crystallization produced troctolites with immiscible sulfide melt droplets within the mafic crust. Instability of the mafic crust led to deep subduction and re-equilibration at 4 6 GPa. Phase relationships plus the presence of a sample with appreciable modal corundum but no Eu anomaly suggest that kyanite- and corundum-bearing eclogites may also originate as plagioclase-free, higher pressure cumulates of highly aluminous clinopyroxene, spinel, and olivine. This is consistent with the crystallizing phase assemblage from an olivine tholeiitic to picritic magma deeper in the Archean oceanic crust or uppermost mantle. We postulate that the magmatic and subduction processes driving modern plate tectonics already existed in the Meso- to Early Archean.
DS201708-1671
2017
Hoefer, H.E.Hoefer, H.E.Redox state of Archean kyanite/corundum eclogites and garnet pyroxenites from Bellsbank, South Africa.11th. International Kimberlite Conference, PosterAfrica, South Africadeposit - Bellsbank

Abstract: An oceanic crustal origin is the commonly accepted paradigm for mantle-derived eclogites. However, the significance of the aluminous members of the eclogite suite, containing kyanite and corundum, has long been underrated and their role neglected in genetic models of cratonic evolution. Here, we present a geochemical and petrological study of a suite of kyanite- and corundum-bearing eclogites from the Bellsbank kimberlite, S. Africa, which originate from depths between 150 and 200 km. Although clearly of high-pressure provenance, these rocks had a low-pressure cumulative origin with plagioclase and olivine as major cumulate phases. This is shown by the very pronounced positive Eu anomalies, low REE abundances, and d18O values lower than the Earth’s mantle. Many chemical features are identical to modern-day troctolitic cumulates including a light REE depletion akin to MORB, but there are also distinguishing features in that the eclogites are richer in Na, Fe, and Ni. Two of the eclogites have a minimum age of ~3.2 Ga, defined by the extremely unradiogenic 87Sr/86Sr (0.7007) in clinopyroxene. Phase equilibria indicate that the parent melts were formed by partial melting below an Archean volcanic center that generated (alkali-)picritic to high-alumina tholeiitic melts from a mantle whose oxygen fugacity was lower than today. Fractional crystallization produced troctolites with immiscible sulfide melt droplets within the mafic crust. Instability of the mafic crust led to deep subduction and re-equilibration at 4–6 GPa. Phase relationships plus the presence of a sample with appreciable modal corundum but no Eu anomaly suggest that kyanite- and corundum-bearing eclogites may also originate as plagioclase-free, higher pressure cumulates of highly aluminous clinopyroxene, spinel, and olivine. This is consistent with the crystallizing phase assemblage from an olivine tholeiitic to picritic magma deeper in the Archean oceanic crust or uppermost mantle. We postulate that the magmatic and subduction processes driving modern plate tectonics already existed in the Meso- to Early Archean.
DS2003-0593
2003
Hoefer, T.Hoefer, T.Diavik - Canada's newest diamond mine, NWTCordilleran Exploration Roundup, p. 79 abstract.Northwest TerritoriesNews item, Diavik
DS200512-0438
2005
Hoefer, T.Hoefer, T.Diavik - the art of the possible.CIM Mining Rocks April 24-27th. Toronto Annual Meeting, Paper# 1915 AbstractCanada, Northwest TerritoriesNews item - Diavik
DS200812-0478
2008
Hoefer, T.Hoefer, T.Diavik update: the first five years.Prospectors and Developers Association of Canada, March 3, 1/8p. abstract.Canada, Northwest TerritoriesDiavik overview
DS201312-0394
2013
Hoefer, T.Hoefer, T.Challenges and opportunities in the Northwest Territories and Nunavut Chamber of Mines, Yellowknife, Canada.PDAC 2013, abstract only.Canada, Northwest Territories, NunavutBrief overview
DS2003-0594
2003
Hoeferm H.E.Hoeferm H.E., Brey, G.P., Woodland, A.B.Iron oxidation state of mantle minerals determined from L emission spectra by the8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractGlobalBlank
DS200612-1411
2006
HoefsTappe, S., Foley, S.F., Jenner, G.A., Heaman, L.M., Kjarsgaard, B.A., Romer,R.L., Stracke, A., Joyce, HoefsGenesis of ultramafic lamprophyres and carbonatites at Aillik Bay, Labrador: a consequence of incipient lithospheric thinning beneath the North Atlantic CratonJournal of Petrology, Vol. 47,7, pp. 1261-1315.Canada, LabradorCarbonatite
DS1986-0430
1986
Hoefs, J.Kempton, P.D., Moorbath, S., Harmon, R.S., Hoefs, J.Heterogeneous lower crust beneath southeast Arizona: evidence fromgranulitexenoliths, Geronimo volcanic fieldGeological Society of America, Vol. 18, No. 2, p. 124. (abstract.)Colorado Plateau, ArizonaMantle
DS1987-0802
1987
Hoefs, J.Woenrer, G., Harmon, R.S., Hoefs, J.Stable isotope relations in an open magma system, Laacher See, EifelContributions to Mineralogy and Petrology, Vol. 95, No. 3, pp. 343-349GermanyLeucitite
DS1989-1545
1989
Hoefs, J.Veizer, J., Hoefs, J., Lowe, D.R., Thurston, P.C.Geochemistry of Precambrian carbonates. 2. Archean greenstone belts and Archean sea waterGeochimica et Cosmochimica Acta, Vol. 53, No. 4, April pp. 859-872. Database # 17926GlobalGeochemistry, Greenstone Belts, Precambrian
DS1989-1546
1989
Hoefs, J.Veizer, J., Hoefs, J., Ridler, R.H., Jensen, L.S., Lowe, D.R.Geochemistry of Precambrian carbonates. 1. Archean hydrothermal systemsGeochimica et Cosmochimica Acta, Vol. 53, No. 4, April pp. 845-858. Database # 17926GlobalGeochemistry, Precambrian
DS1992-0755
1992
Hoefs, J.Ionov, D.A., Hoefs, J., Wedepohl, K.H., Wiechert, U.Content and isotopic composition of sulphur in ultramafic xenoliths from central AsiaEarth and Planetary Science Letters, Vol. 111, pp. 269-286GlobalGeochronology, Xenoliths
DS1993-0718
1993
Hoefs, J.Ionov, D.A., Hoefs, J., Wedepohl, K.H., Wiechert, U.Content of sulfur in different mantle reservoirs - replyEarth and Planetary Sciences, Vol. 119, No. 4, October, pp. 635-640.AsiaXenoliths, Mantle
DS1995-0753
1995
Hoefs, J.Harmon, R.S., Hoefs, J.Oxygen isotope heterogeneity of the mantle deduced from global Osystematics of basalts from different settingsContributions to Mineralogy and Petrology, Vol. 120, No. 1, pp. 95-114MantleGeochronology, Geotectonics
DS1998-1605
1998
Hoefs, J.Xiao, Y.L., Hoefs, J., Van der Kerkof, A.M., Zheng, Y.Fluid inclusions in ultra high pressure eclogites from the Dabie Shan, eastern China.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1667-8.ChinaEclogites, metamorphic, Deposit - Dabie Shan
DS2000-1030
2000
Hoefs, J.Xiao, Y., Hoefs, J., Zheng, Y.Fluid history of ultra high pressure (UHP) metamorphism in Dabie Shan: a fluid inclusion and oxygen isotope coesite-bearing....Contrib. Min. Pet., Vol. 139, No. 1, pp. 1-16.ChinaEclogite, Bixiling area
DS2001-1267
2001
Hoefs, J.Xiao, Y.L., Hoefs, J., Li, S.G.Geochemical constraints of the eclogite and granulite facies metamorphism as recognized in Raobazhai Complex.Journal of Metamorphic Geology, Vol. 19, No. 1, Jan. pp. 3-20.ChinaGeochemistry, Dabie Shan
DS2002-0406
2002
Hoefs, J.Druppel, K., Hoefs, J., Litmann, S., Okrusch, M.Carbonatite related fenitisation processes at the southern margin of the Kunene intrusive complex, NW Namibia.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.250.Namibiacarbonatite - mineralogy
DS2002-1746
2002
Hoefs, J.Xiao, Y., Hoefs, J., Van den Kerkof, A.M., Simon, K., Fiebig, J., Zheng, Y.F.Fluid evolution in the Baia Mare epithermal gold/polymetallic district, Inner Carpathians, RomaniaJournal of Petrology, Vol. 43, No. 8, pp. 1505-28.ChinaGeochemistry, UHP
DS200512-0248
2005
Hoefs, J.Druppel, K., Hoefs, J., Okrusch, M.Fenitizing processes induced by ferrocarbonatite magmatism at Swartbooisdrif, northwest Namibia.Journal of Petrology, Vol. 46, no. 2, pp. 377-406.Africa, NamibiaCarbonatite
DS200512-1205
2005
Hoefs, J.Xiao, Y., Hoefs, J., Kronz, A.Compositionally zoned Cl rich amphiboles from North Dabie Shan, China: monitor of high pressure metamorphic fluid rock interaction processes.Lithos, Vol. 81, 1-4, April pp. 279-295.ChinaUHP
DS200512-1234
2005
Hoefs, J.Zeming, Z., Kun, S., Van den Kerkhof, A.M., Hoefs, J., Liou, J.G.Fluid composition and evolution attending UHP metamorphism: study of fluid inclusions from drill cores, southern Sulu Belt, eastern China.International Geology Review, Vol. 47, 3, pp. 297-309.ChinaUHP
DS200512-1251
2005
Hoefs, J.Zhang, Z., Xiao, Y., Liu, F., Liou, J.G., Hoefs, J.Petrogenesis of UHP metamorphic rocks from Qinglongshan, southern Sulu east central China.Lithos, Vol. 81, 1-4, April pp. 189-207.ChinaUHP
DS200612-1554
2006
Hoefs, J.Xiao, Y., Sun, W., Hoefs, J., Simon, K., Zhang, Z., Li, S., Hofmann, A.W.Making continental crust through slab melting: constraints from niobium tantalum fractionation in UHP metamorphic rutile.Geochimica et Cosmochimica Acta, Vol. 70, 18, Sept. 15, pp. 4770-47082.ChinaDabie Sulu - eclogites - UHP
DS200612-1596
2005
Hoefs, J.Zhang, Z., Xiao, Y., Hoefs, J., Xu, Z., Liou, J.G.Petrogenesis of UHP metamorphic crustal and mantle rocks from the Chinese continent in the main hole pre-pilot hole 1 Sulu Basin.International Geology Review, Vol. 47, 11, pp. 1160-1177.Asia, ChinaUHP
DS200712-0952
2007
Hoefs, J.Schmidt, A., Weyer, S., Xiao, Y., Hoefs, J., Brey, G.P.Lu Hf geochronology of eclogites from the Dabie Sulu terrain: constraints on the timing of eclogite facies metamorphism.Plates, Plumes, and Paradigms, 1p. abstract p. A894.ChinaUHP
DS200812-1020
2008
Hoefs, J.Schmidt, A., Weyer, S., Mezger, K., Scherer, E.E., Xiao, Y., Hoefs, J., Brey, G.P.Rapid eclogization of the Dabie Sulu UHP terrane: constraints from Lu Hf garnet geochronology.Earth and Planetary Science Letters, Vol. 273, 1-2, Aug. 30, pp. 203-213.ChinaUHP
DS200812-1021
2008
Hoefs, J.Schmidt, A., Weyer, S., Mezger, K., Scherer, E.E., Xiao, Y., Hoefs, J., Brey, G.P.Rapid eclogitization of the Dabie Sulu UHP terrane: constraints from Lu Hf garnet geochronology.Earth and Planetary Science Letters, In press available, 49p.ChinaUHP
DS201012-0281
2010
Hoefs, J.Hoefs, J.The stable isotope composition of the mantle - revisited.Goldschmidt 2010 abstracts, abstractMantleGeochronology
DS201012-0282
2010
Hoefs, J.Hoefs, J.Geochemical fingerprints: a critical appraisal.European Journal of Mineralogy, Vol. 22, Feb. no. 1, pp. 3-15.TechnologyMineral chemistry
DS201312-0485
2013
Hoemle, K.Kipl, A.F., Werner, R., Gohl, K., Van den Bogaard, P., Hoemle, K., Maichur, D., Klugel, A.Seamounts off the West Antarctic margin: a case for non-hotpsot driven intra-plate volcanism.Gondwana Research, Vol. 25, 4, pp. 1660-1679.AntarcticaIntra-plate volcanism
DS1930-0065
1931
Hoen, C.W.A.P.Hoen, C.W.A.P.Mededeeling Over Een Vondst Van Diamanten in de Siaboe Rivier, Ten Zuiden Van Bangkinang ( Midden Sumatra).De Mijningenieur., Vol. 12, OCTOBER PP. 176-178.Southeast Asia, SumatraDiamond
DS2002-0728
2002
Hoenle, K.Hoenle, K., Tilton, G., LeBas, Duggen, GarbeSchonbergGeochemistry of oceanic carbonatites compared with continental carbonatites; mantle recycling of oceanic..Contribution to Mineralogy and Petrology, Vol.142, 5, pp.520-42.Mantle, OceanicCarbonatite - recycling crustal carbonate
DS200612-0590
2006
Hoepffner, C.Hoepffner, C., Houari, M.R., Bouabdelli, M.Tectonics of the North African Variscides ( Morocco, western Algeria): an outline.Comptes Rendus Geoscience, Vol. 338, 1-2, pp. 25-40.Africa, Morocco, AlgeriaTectonics
DS200612-0591
2006
Hoepffner, C.Hoepffner, C., Rachid Houari, M., Bouabdelli, M.Tectonics of the North African Variscides ( Morocco, western Algeria) - an outline.Comptes Rendus Geoscience, Vol. 338, 1-2, pp. 25-Africa, MoroccoTectonics
DS1984-0375
1984
Hoernes, S.Jagoutz, E., Dawson, J.B., Hoernes, S., Spettel, B., Waenke, H.Anorthositic Oceanic Crust in the Archean EarthLunar and Planetary Science Conference 15th. Abstract Volume, Vol. 15, pp. 395-396GlobalAnorthosite
DS2002-0793
2002
Hoernes, S.Jung, S., Hoernes, S., Mezger, K.Synorogenic melting of mafic lower crust: constraints from geochronology, petrology and Sr Nd, Pb and O isotope geochemistry of quartz diorites, Damara OrogenContributions to Mineralogy and Petrology, Vol.NamibiaGeochronology - not specific to diamonds
DS2002-0794
2002
Hoernes, S.Jung, S., Hoernes, S., Mezger, K.Synorogenic melting of mafic lower crust: constraints from geochronology, petrology and Sr Nd Pb O isotope geochemistry of diorites from Damara Origin.Contributions to Mineralogy and Petrology, Vol. 143, 5, pp.551-66.NamibiaGeochronology - not specific to diamonds
DS2003-0675
2003
Hoernes, S.Jung, S., Mezger, K., Hoernes, S.Petrology of basement dominated terranesChemical Geology, Vol. 199, No. 1-2, pp. 1-28.GlobalBlank
DS200412-0937
2004
Hoernes, S.Jung, S., Merger, K., Hoernes, S.Shear zone related syenites in the Damara belt ( Namibia): the role of crustal contamination and source composition.Contributions to Mineralogy and Petrology, Vol. 148, 1, pp. 104-121.Africa, NamibiaGeneral geology - not specific to diamonds
DS200412-0939
2003
Hoernes, S.Jung, S., Mezger, K., Hoernes, S.Petrology of basement dominated terranes.Chemical Geology, Vol. 199, no. 1-2, pp. 1-28.TechnologyTectonics
DS200712-0851
2007
Hoernie, K.Portnyagin, M., Hoernie, K., Plechov, P., Mironov, N., Khubunaya, S.Constraints on mantle melting and composition and nature of slab components in volcanic arcs from volatiles ( H2) S Cl F) and trace elements in melt inclusions from the Kamchatka Arc.Earth and Planetary Science Letters, Vol. 255, 1-2, pp. 53-69.Russia, KamchatkaGeochemistry
DS1989-0648
1989
Hoernie, K.A.Hoernie, K.A., Tilton, G., Le Bas, M.J., Staudigel, H.A plume origin for Fuerteventura (Canary Islands) carbonatitesEos, Vol. 70, No. 15, April 11, p. 503. (abstract.)GlobalCarbonatite
DS200512-0088
2005
HoernleBindeman, I.N., Eiler, J.M., Yogodzinski, Y., Stern, C.R., Grove, T.L., Portnyagin, Hoernle, DanyushevskyOxygen isotope evidence for slab melting in modern and ancient subduction zones.Earth and Planetary Science Letters, Vol. 235, 3-4, July 15, pp. 480-496.MantleSubduction
DS200912-0189
2009
Hoernle, F.Duggen, K.A., Hoernle, F., Hauff, A., Klugel, M., Bouabdellah, Thirwall, M.F.Flow of Canary mantle plume material through a subcontinental lithospheric corridor beneath Africa to the Mediterranean.Geology, Vol. 37, 3, pp. 283-286.EuropePlume
DS1993-0678
1993
Hoernle, K.Hoernle, K., Schmincke, H-U.The role of partial melting in the 15 Ma geochemical evolution of GranCanaria: a blob model for the Canary hotspotJournal of Petrology, Vol. 34, No. 3, June pp. 573-599GlobalAlkaline rocks, Geochemistry
DS1993-0679
1993
Hoernle, K.Hoernle, K., Schmincke, H-U.The petrology of the tholeiites through melilite nephelinites on Gran Canaria Canary Islands: crystal fractionation, accumulation and depths ofmeltingJournal of Petrology, Vol. 34, No. 3, June pp. 543-572GlobalAlkaline rocks, Geochronology
DS1995-0810
1995
Hoernle, K.Hoernle, K., et al.Seismic and geochemical evidence for large scale mantle upwelling beneath the eastern Atlantic and western and Central Europe.Nature, Vol. 374, March 2, pp. 34-9.EuropeGeophysics - seismics, Mantle geodynamics, tectonics, hotspots
DS2000-0323
2000
Hoernle, K.Geldmacher, J., Hoernle, K.The 72 Ma geochemical evolution of the Madeira hot spot ( eastern North Atlantic): recycling of Paleozoic....Earth and Planetary Science Letters, Vol.183, No.1-2, Nov.30, pp.73-92.MantleOceanic lithosphere, Geochemistry
DS2002-0729
2002
Hoernle, K.Hoernle, K., Tilton, Le Bas, Duggen, Garbe-SchonbergGeochemistry of oceanic carbonatites compared with continental carbonatites: mantle recycling of oceanic..Contributions to Mineralogy and Petrology, Vol. 142, No. 5, Feb. pp. 520-42.MantleGeochemistry, Carbonatite - crustal carbonate
DS2002-0730
2002
Hoernle, K.Hoernle, K., Van den Bogaard, P., Werner, R., Lissinaa, B., Hauff, F., AlvaradoMissing history ( 16 -71 Ma) of the Galapagos hotspot: implications for the tectonicGeology, Vol. 30, 9, Sept. pp. 795-98.United StatesTectonics
DS200612-0723
2006
Hoernle, K.Kokfelt, T.F., Hoernle, K., Hauff, F., Fiebig, J., Werner, R., Garbe-Schonberg, D.Combined trace element and Pb Nd Sr and O isotope evidence for recycled oceanic crust ( upper and lower) in the Iceland mantle plume.Journal of Petrology, Vol. 47, 9, Sept. pp. 1705-1749.Europe, IcelandGeochronology, subduction
DS200812-0392
2008
Hoernle, K.Geldmacher, J., Hoernle, K., Lgel, A., Van den Bogaard, P., Bindeman, I.Geochemistry of a new enriched mantle type locality in the northern hemisphere: implications for the origin of the EM-I source.Earth and Planetary Science Letters, Vol. 265, 1-2, pp. 167-182.MantleGeophysics - EM
DS200812-0420
2007
Hoernle, K.Goldmacher, J., Hoernle, K., Klugel, A., Van den Bogaard, P., Bindeman, I.Geochemistry of a new enriched mantle type locality in the northern hemisphere: implications for the origin of the EM-I source.Earth and Planetary Science Letters, Vol. 265, 1-2, pp. 167-182.MantleMetasomatism
DS201012-0068
2010
Hoernle, K.Bouabdellah, M., Hoernle,K., Kchit, A., Duggen, S., Hauff, Klugel, Lowry, BeaudoinPetrogenesis of the Eocene Tamzert continental carbonatites ( central High Atlas, Morocco): implications for a common source for Tamzert and CanaryJournal of Petrology, Vol. 51, 8, pp. 1655-1686.Europe, Canary Islands, MoroccoCarbonatite
DS201806-1227
2018
Hoernle, K.Homrighausen, S., Hoernle, K., Hauff, J., Geldmacher, J., Garbe-Schonberg, D.Global distribution of the HIMU end member: formation through Archean plume lid tectonics.Earth Science Reviews, Vol. 182, pp. 85-101.Globaltectonics

Abstract: Oceanic basalts reflect the heterogeneities in the earth's mantle, which can be explained by five mantle end members. The HIMU end member, characterized by high time-integrated µ (238U/204Pb), is defined by the composition of lavas from the ocean islands of St. Helena, South Atlantic Ocean and Mangaia and Tubuai (Cook-Austral Islands), South Pacific Ocean. It is widely considered to be derived from a mantle reservoir that is rarely sampled and not generally involved in mixing with the other mantle components. On the other hand, the FOZO end member, located at the FOcal ZOne of oceanic volcanic rock arrays on isotope diagrams, is considered to be a widespread common component with slightly less radiogenic 206Pb/204Pb and intermediate Sr-Nd-Hf isotopic compositions. Here we present new major and trace element, Sr-Nd-Pb-Hf isotope and geochronological data from the Walvis Ridge and Richardson Seamount in the South Atlantic Ocean and the Manihiki Plateau and Eastern Chatham Rise in the southwest Pacific Ocean. Our new data, combined with literature data, document a more widespread (nearly global) distribution of the HIMU end member than previously postulated. Our survey shows that HIMU is generally associated with low-volume alkaline, carbonatitic and/or kimberlitic intraplate volcanism, consistent with derivation from low degrees of melting of CO2-rich sources. The majority of end member HIMU locations can be directly related to hotspot settings. The restricted trace element and isotopic composition (St. Helena type HIMU), but near-global distribution, point to a deep-seated, widespread reservoir, which most likely formed in the Archean. In this context we re-evaluate the origin of a widespread HIMU reservoir in an Archean geodynamic setting. We point out that the classic ocean crust recycling model cannot be applied in a plume-lid dominated tectonic setting, and instead propose that delamination of carbonatite-metasomatized subcontinental lithospheric mantle could be a suitable HIMU source.
DS200912-0273
2009
Hoernle, K.A.Gurenko, A.A., Sobolev, A.V., Hoernle, K.A., Hauff, F., Schincka, H-U.Enriched, HIMU type peridotite and depleted recycled pyroxenite in the Canary plume: a mixed up mantle.Earth and Planetary Science Letters, Vol. 277, 3-4, Jan. 30, pp. 514-524.Europe, Canary IslandsGeothermometry - subduction
DS1985-0334
1985
Hoersch, A.L.Keller, W.D., Stone, C.G., Hoersch, A.L.Textures of Paleozoic Chert and Novaculite in the Ouachita Mountains of Arkansaw and Oklahoma and Their Geological Significance.Geological Society of America (GSA) Bulletin., Vol. 96, No. 11, NOVEMBER PP. 1353-1363.United States, Gulf Coast, Arkansas, OklahomaPetrography
DS1996-0455
1996
Hoey, T.Ferguson, R., Hoey, T., Wathen, S., Werrity, A.Field evidence for rapid Down stream fining of river gravels through selective transport.Geology, Vol. 24, No. 2, Feb. pp. 179-182.ScotlandGeomorphology -river gravels, Not specific to diamonds -general, River gravels, alluvials
DS201112-0796
2011
Hoey, T.B.Piedra, M.M., Haynes, H., Hoey, T.B.The spatial distribution of coarse surface grains and the stability of gravel.Sedimentology, In press availableTechnologyGravel bedforms - not specific to diamonds
DS201112-0364
2011
Hofer, H & E.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H & E., Keller, J.In situ trace element and U Pb and Sr and Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.48-50.Europe, GermanyKaiserstuhl
DS201112-0365
2011
Hofer, H & E.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H & E., Keller, J.In situ trace element and U Pb and Sr and Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.48-50.Europe, GermanyKaiserstuhl
DS1994-0530
1994
Hofer, H.Foley, S., Hofer, H., Brey, G.high pressure synthesis of Priderite and members of Lindsleyite-mathiasite and hawthornite-Yimengite seriesContributions to Mineralogy and Petrology, Vol. 117, No. 2, July, pp. 164-174.GlobalMineralogy, Priderite
DS200812-0249
2009
Hofer, H.Creighton, S., Stachel, S., Matveev, S., Hofer, H., McCammon, C., Luth, R.W.Oxidation of the Kaapvaal lithospheric mantle driven by metasomatism.Contributions to Mineralogy and Petrology, Vol. 157, pp. 491-504.Africa, South AfricaMetasomatism, Kimberley
DS200912-0135
2009
Hofer, H.Creighton, S.,Stachel, T., Matveev, S., Hofer, H., McCammon, C., Luth, R.W.Oxidation of the Kaapvaal lithospheric mantle driven by metasomatism.Contributions to Mineralogy and Petrology, Vol. 157, 4, pp. 491-504.Africa, South AfricaMetasomatism
DS201910-2260
2019
Hofer, H.Graf, C., Sandner, T., Woodland, A., Hofer, H., Seitz, H-M., Pearson, G., Kjarsgaard, B.Metasomatism, oxidation state of the mantle beneath the Rae craton, Canada.Goldschmidt2019, 1p. AbstractCanadacraton

Abstract: The Rae craton is an important part of the Canadian Shield and was amalgamated to the Slave craton at ?? 1.9 Ga [1]. Recent geophysical and geochemical data indicate a protracted geodynamic history [1, 2]. Even though the oxidation state of the Earth’s mantle has an important influence of fluid compositions and melting behavior, no data on the oxidation state of the Rae’s mantle are available. The aims of this study were to 1) determine the oxidation state (ƒO2) of the lithosphere beneath the Rae craton, 2) link these results to potential metasomatic overprints and 3) compare the geochemical evolution with the Slave craton. We studied 5 peridotite xenoliths from Pelly Bay (central craton) and 22 peridotites from Somerset Island (craton margin). Pelly Bay peridotites give T < 905°C and depths of ??80- 130 km. Garnets have depleted or “normal” REE patterns, the latter samples recording fO2 values ??0.5 log units higher. The deeper samples are more enriched and oxidised. Peridotites from Somerset Island record T ??825-1190°C, a ?logfO2 ranging from ?? FMQ - FMQ-3.6 from a depth interval of ??100-150 km. Garnets exhibit two REE signatures - sinusoidal and “normal” - indicating an evolutionary sequence of increasing metasomatic re-enrichment and a shift from fluid to melt dominated metasomatism. Compared to the Slave craton, the Rae mantle is more reduced at ??80km but becomes up to 2 log units more oxidised (up to ??FMQ-1) at ??100-130 km. Similar oxidising conditions can be found >140 km in the Slave mantle [3]. Especially under Somerset Island, the lithospheric mantle has contrasting fO2 and metasomatic overprints in the same depth range, which may represent juxtaposed old and rejuvenated domains [2].
DS200612-0592
2006
Hofer, H.E.Hofer, H.E., Brey, G.P., Yaxley, G.M., Berry, A.J.Iron oxidation state determination in garnets by EPMA and XANES.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 256. abstract only.TechnologyGarnet geochemistry
DS200912-0307
2009
Hofer, H.E.Hofer, H.E., Lazarov, M., Brey, G.P., Woodland, A.B.Oxygen fugacity of the metasomatizing melt in a polymict peridotite from Kimberley.Lithos, In press - available 25p.Africa, South AfricaDeposit - Kimberley
DS201112-0366
2011
Hofer, H.E.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H.E., Keller, J.In-situ trace element and U-Pb, Sr and Nd isotope analysis of accessory phases in Kaiserstuhl cabonatites.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GermanyCarbonatite
DS201212-0237
2012
Hofer, H.E.Ghobadi, M., Gerdes, A., Brey, G.P., Hofer, H.E., Keller, J.In situ trace element and U Pb and Sr Nd isotope analysis of accessory phases in Kaiserstuhl carbonatites.emc2012 @ uni-frankfurt.de, 1p. AbstractEurope, GermanyCarbonatite
DS201212-0653
2012
Hofer, H.E.Shu, Q., Brey, G.P., Gerdes, A., Hofer, H.E., Seitz, H.M.Eclogites and garnet pyroxenites from the mantle: their age and ageing- two point isochrons, Sm-Nd and Lu-Hf closure temperatures, model ages.emc2012 @ uni-frankfurt.de, 1p. AbstractAfrica, South AfricaDeposit - Bellsbank
DS201312-0312
2013
Hofer, H.E.Girnis, A.V., Bulatov, V.K., Brey, G.P., Gerdes, A., Hofer, H.E.Trace element partitioning between mantle minerals and silico-carbonate melts at 6-12 Gpa and applications to mantle metasomatism and kimberlite genesis.Lithos, Vol. 160-161, pp. 183-200.MantleKimberlite genesis, melting
DS201312-0555
2013
Hofer, H.E.Luchs, T., Brey, G.P., Gerdes, A., Hofer, H.E.The lithospheric mantle underneath the Gibeon kimberlite field ( Namibia): a mix of old and young components - evidence from Lu-Hf and Sm-Nd isotope systematics.Precambrian Research, Vol. 231, pp. 263-276.Africa, NamibiaDeposit - Gibeon
DS201509-0386
2015
Hofer, H.E.Brey, G.P., Girnis, A.V., Bulatov, V.K., Hofer, H.E., Gerdes, A., Woodland, A.B.Reduced sediment melting at 7.5-12 Gpa: phase relations, geochemical signals and diamond nucleation.Contributions to Mineralogy and Petrology, Vol. 170, 25p.TechnologyExperimental petrology

Abstract: Melting of carbonated sediment in the presence of graphite or diamond was experimentally investigated at 7.5–12 GPa and 800–1600 °C in a multianvil apparatus. Two starting materials similar to GLOSS of Plank and Langmuir (Chem Geol 145:325–394, 1998) were prepared from oxides, carbonates, hydroxides and graphite. One mixture (Na-gloss) was identical in major element composition to GLOSS, and the other was poorer in Na and richer in K (K-gloss). Both starting mixtures contained ~6 wt% CO2 and 7 wt% H2O and were doped at a ~100 ppm level with a number of trace elements, including REE, LILE and HFSE. The near-solidus mineral assemblage contained a silica polymorph (coesite or stishovite), garnet, kyanite, clinopyroxene, carbonates (aragonite and magnesite-siderite solid solution), zircon, rutile, bearthite and hydrous phases (phengite and lawsonite at <9 GPa and the hydrous aluminosilicates topaz-OH and phase egg at >10 GPa). Hydrous phases disappear at ~900 °C, and carbonates persist up to 1000-1100 °C. At temperatures >1200 °C, the mineral assemblage consists of coesite or stishovite, kyanite and garnet. Clinopyroxene stability depends strongly on the Na content in the starting mixture; it remains in the Na-gloss composition up to 1600 °C at 12 GPa, but was not observed in K-gloss experiments above 1200 °C. The composition of melt or fluid changes gradually with increasing temperature from hydrous carbonate-rich (<10 wt% SiO2) at 800-1000 °C to volatile-rich silicate liquids (up to 40 wt% SiO2) at high temperatures. Trace elements were analyzed in melts and crystalline phases by LA ICP MS. The garnet-melt and clinopyroxene-melt partition coefficients are in general consistent with results from the literature for volatile-free systems and silicocarbonate melts derived by melting carbonated peridotites. Most trace elements are strongly incompatible in kyanite and silica polymorphs (D < 0.01), except for V, Cr and Ni, which are slightly compatible in kyanite (D > 1). Aragonite and Fe-Mg carbonate have very different REE partition coefficients (D Mst-Sd/L ~ 0.01 and D Arg/L ~ 1). Nb, Ta, Zr and Hf are strongly incompatible in both carbonates. The bearthite/melt partition coefficients are very high for LREE (>10) and decrease to ~1 for HREE. All HFSE are strongly incompatible in bearthite. In contrast, Ta, Nb, Zr and Hf are moderately to strongly compatible in ZrSiO4 and TiO2 phases. Based on the obtained partition coefficients, the composition of a mobile phase derived by sediment melting in deep subduction zones was calculated. This phase is strongly enriched in incompatible elements and displays a pronounced negative Ta-Nb anomaly but no Zr-Hf anomaly. Although all experiments were conducted in the diamond stability field, only graphite was observed in low-temperature experiments. Spontaneous diamond nucleation and the complete transformation of graphite to diamond were observed at temperatures above 1200-1300 °C. We speculate that the observed character of graphite-diamond transformation is controlled by relationships between the kinetics of metastable graphite dissolution and diamond nucleation in a hydrous silicocarbonate melt that is oversaturated in C.
DS201804-0688
2017
Hofer, H.E.Forster, B., Aulbach, S., Symes, C., Gerdes, A., Hofer, H.E., Chacko, T.A reconnaissance study of Ti minerals in cratonic granulite xenoliths and their potential as recorders of lower crust formation and evolution.Journal of Petrology, Vol. 58, 10, pp. 2007-2034.Canada, Northwest Territoriesdeposit - Diavik

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

Abstract: The cratonic part of Greenland has been a hotspot of scientific investigation since the discovery of some of the oldest crust on Earth and of significant diamond potential in the underlying lithospheric mantle, the characterization of which remains, however, incomplete. We applied a detailed petrographic and in situ analytical approach to a new suite of fresh kimberlite-borne peridotite xenoliths, recovered from the North Atlantic craton in SW Greenland, to unravel the timing and nature of mantle metasomatism, and its link to the formation of low-volume melts (e.g. kimberlites) and to geophysically detectible discontinuities. Two types of mineralogies and metasomatic styles, occurring at two depth intervals, are recognized. The first type comprises lherzolites, harzburgites and dunites, some phlogopite-bearing, which occur from ~100-170?km depth. They form continuous trends towards lower mineral Mg# at increasing TiO2, MnO and Na2O and decreasing NiO contents. These systematics are ascribed to metasomatism by a hydrous silicate melt precursor to c. 150?Ma kimberlites, in the course of rifting, decompression and lithosphere thinning. This metasomatism was accompanied by progressive garnet breakdown, texturally evident by pyroxene-spinel assemblages occupying former coarse grains and compositionally evident by increasing concentrations of elements that are compatible in garnet (Y, Sc, In, heavy rare earth elements) in newly formed clinopyroxene. Concomitant sulphide saturation is indicated by depletion in Cu, Ni and Co. The residual, more silica-undersaturated and potentially more oxidizing melts percolated upwards and metasomatized the shallower lithospheric mantle, which is composed of phlogopite-bearing, texturally equilibrated peridotites, including wehrlites, showing evidence for recent pyroxene-breakdown. This is the second type of lithology, which occurs at ~90-110?km depth and is inferred to have highly depleted protoliths. This type is compositionally distinct from lherzolites, with olivine having higher Ca/Al, but lower Al and V contents. Whereas low Al may in part reflect lower equilibration temperatures, low V is ascribed to a combination of intrinsically more oxidizing mantle at lower pressure and oxidative metasomatism. The intense metasomatism in the shallow cratonic mantle lithosphere contrasts with the strong depletion recorded in the northwestern part of the craton, which at 590-550?Ma extended to >210?km depth, and suggests loss of ~40?km of lithospheric mantle, also recorded in the progressive shallowing of magma sources during the breakup of the North Atlantic craton. The concentration of phlogopite-rich lithologies in a narrow depth interval (~90-110?km) overlaps with a negative seismic velocity gradient that is interpreted as a mid-lithospheric discontinuity beneath western Greenland. This is suggested to be a manifestation of small-volume volatile-rich magmatism, which paved the way for Mesozoic kimberlite, ultramafic lamprophyre, and carbonatite emplacement across the North Atlantic craton.
DS201805-0945
2018
Hofer, H.E.Girnis, A.V., Brey, G.P., Bulatov, V.K., Hofer, H.E., Woodland, A.B.Graphite to diamond transformation during sediment-peridotite interaction at 7.5 and 10.5 Gpa.Lithos, in press available 42p.Mantleperidotites

Abstract: Diamond nucleation and growth were investigated experimentally at 7.5 and 10.5?GPa and temperatures up to 1500?°C. Samples consisted of two layers: i) H2O- and CO2-bearing model sediment and ii) graphite-bearing garnet harzburgite comprising natural minerals. Two experimental series were conducted, one under a controlled temperature gradient with the sedimentary layer usually in the cold zone and the other under isothermal conditions. In the latter case, diamond seeds were added to the sedimentary mixture. During the experiments, the sedimentary layer partially or completely melted, with the melt percolating and interacting with the adjacent harzburgite. The graphite-to-diamond transition in the peridotite was observed above 1300?°C at 7.5?GPa and 1200?°C at 10.5?GPa in the temperature-gradient experiments, and at temperatures ~100?°C lower in the isothermal experiments with diamond seeds. Newly formed diamond occurs mostly as individual grains up to 10?µm in size and is separate from graphite aggregates. In some cases, an association of diamond with magnesite was observed. Diamond nucleation occurs in hydrous and CO2-bearing silicate melt following graphite dissolution and recrystallization. In the case of the diamond-magnesite association, diamond was probably formed through carbonate reduction coupled with graphite oxidation. The composition of the melts ranged from “carbonatitic” with ~10?wt% SiO2 and?>?50?wt% volatiles to hydrous silicate with ~40?wt% SiO2 and?
DS201806-1248
2018
Hofer, H.E.Seitz, H-M., Brey, G.P., Harris, J.W., Durali-Muller, S., Ludwig, T., Hofer, H.E.Ferropericlase inclusions in ultradeep diamonds from Sao Luiz ( Brazil): high Li abundances and diverse Li-isotope and trace element compositions suggest an origin from a subduction melange.Mineralogy and Petrology, in press available, 10p.South America, Brazil, Juinadeposit - Sao Luiz

Abstract: The most remarkable feature of the inclusion suite in ultradeep alluvial and kimberlitic diamonds from Sao Luiz (Juina area in Brazil) is the enormous range in Mg# [100xMg/(Mg?+?Fe)] of the ferropericlases (fper). The Mg-richer ferropericlases are from the boundary to the lower mantle or from the lower mantle itself when they coexist with ringwoodite or Mg- perovskite (bridgmanite). This, however, is not an explanation for the more Fe-rich members and a lowermost mantle or a “D” layer origin has been proposed for them. Such a suggested ultra-deep origin separates the Fe-rich fper-bearing diamonds from the rest of the Sao Luiz ultradeep diamond inclusion suite, which also contains Ca-rich phases. These are now thought to have an origin in the uppermost lower mantle and in the transition zone and to belong either to a peridotitic or mafic (subducted oceanic crust) protolith lithology. We analysed a new set of more Fe-rich ferropericlase inclusions from 10 Sao Luiz ultradeep alluvial diamonds for their Li isotope composition by solution MC-ICP-MS (multi collector inductively coupled plasma mass spectrometry), their major and minor elements by EPMA (electron probe micro-analyser) and their Li-contents by SIMS (secondary ion mass spectrometry), with the aim to understand the origin of the ferropericlase protoliths. Our new data confirm the wide range of ferropericlase Mg# that were reported before and augment the known lack of correlation between major and minor elements. Four pooled ferropericlase inclusions from four diamonds provided sufficient material to determine for the first time their Li isotope composition, which ranges from d7Li?+?9.6 ‰ to -3.9 ‰. This wide Li isotopic range encompasses that of serpentinized ocean floor peridotites including rodingites and ophicarbonates, fresh and altered MORB (mid ocean ridge basalt), seafloor sediments and of eclogites. This large range in Li isotopic composition, up to 5 times higher than ‘primitive upper mantle’ Li-abundances, and an extremely large and incoherent range in Mg# and Cr, Ni, Mn, Na contents in the ferropericlase inclusions suggests that their protoliths were members of the above lithologies. This mélange of altered rocks originally contained a variety of carbonates (calcite, magnesite, dolomite, siderite) and brucite as the secondary products in veins and as patches and Ca-rich members like rodingites and ophicarbonates. Dehydration and redox reactions during or after deep subduction into the transition zone and the upper parts of the lower mantle led to the formation of diamond and ferropericlase inclusions with variable compositions and a predominance of the Ca-rich, high-pressure silicate inclusions. We suggest that the latter originated from peridotites, mafic rocks and sedimentary rocks as redox products between calcite and SiO2.
DS201906-1269
2019
Hofer, H.E.Aulbach, S., Hofer, H.E., Gerdes, A.High Mg and Low Mg mantle eclogites from Koidu (West African Craton) linked by Neoproterozoic ultramafic melt metasomatism of subducted Archean plateau-like oceanic crust.Journal of Petrology, Vol. 60, 4, pp. 723-754.Africa, Sierra Leonedeposit - Koidu

Abstract: Bimineralic eclogites and pyroxenites (n?=?75?±?accessory rutile, ilmenite, sulphide, apatite) from the Koidu kimberlite (West African Craton) were investigated for mineral major and trace elements and mineral Sr-Nd isotope compositions to constrain (1) the nature and age of their basaltic to picritic protoliths, and (2) the effect, timing and source of mantle metasomatism. Consistent with published work, samples are grouped into low-Mg eclogites with Mg# from 0•49 to 0•73 (median 0•59; n?=?40) and high-Mg eclogites with Mg# from 0•60 to 0•88 (median 0•75; n?=?14), plus pyroxenites [clinopyroxene Na/(Na + Ca) <0•2; n?=?8] and gabbroic eclogites and pyroxenite (Eu/Eu* of reconstructed bulk-rocks >1•05; n?=?8), with five unclassifiable samples. Reconstructed low-Mg and gabbroic eclogites have major and trace element systematics (Eu/Eu*-heavy rare earth elements-Y) indicating crustal protolith crystallisation, confirming an origin as subducted oceanic crust. Their high FeO contents at MgO >~10?wt % require an Fe-rich source, the high melt productivity of which led to the formation of thicker crust, perhaps in a plateau-like setting. This is consistent with SiO2-MgO relationships indicating differentiation at ~0•5?GPa. Unradiogenic Sr in some clinopyroxene (87Sr/86Sr of 0•7010-0•7015), combined with light rare earth element (LREE) depletion relative to normal mid-ocean ridge basalt (N-MORB) for the majority of samples (average N-MORB-normalised Nd/Yb of unmetasomatised samples = 0•51), suggests eclogitisation and partial melt loss in the Neoarchaean, possibly coeval with and parental to 2•7?Ga overlying continental crust. Most reconstructed high-Mg eclogites and some pyroxenites formed by metasomatic overprinting of low-Mg eclogites and gabbroic eclogites, as indicated by the preservation of positive Eu anomalies in some samples, and by the Mg-poorer composition of included versus matrix minerals. Coupled enrichment in MgO, SiO2 and Cr2O3 and in incompatible elements (Sr, LREE, Pb, Th and U) is ascribed to metasomatism by a kimberlite-like, small-volume, carbonated ultramafic melt, mediated by addition of clinopyroxene from the melt (i.e. stealth metasomatism). Strontium-Nd isotope systematics suggest a Neoproterozoic age for this metasomatic event, possibly linked to Rodinia break-up, which facilitated intrusion of asthenospheric carbonated melts with an ocean island basalt-like 87Sr/86Sri of ~0•7035. Cretaceous kimberlite magmatism (including Koidu), with more radiogenic 87Sr/86Sr (~0•7065, intermediate between Kaapvaal kimberlites and orangeites), may have been partially sourced from associated Neoproterozoic metasomes. The presence of diamonds in low-Mg eclogites, but absence in high-Mg eclogites, indicates the diamond-destructive nature of this event. Nevertheless, the moderate proportion of affected eclogites (~35%) suggests preservation of a sizeable diamond-friendly mantle eclogite reservoir beneath Koidu.
DS1993-0680
1993
Hofer, J.W.Hofer, J.W., Szabo, J.P.Port Bruce ice-flow directions based on heavy-mineral assemblages in tills from the south shore of Lake Erie in OhioCanadian Journal of Earth Sciences, Vol. 30, No. 6, June pp. 1236-1241GlobalGeomorphology
DS1982-0280
1982
Hofer, S.Hofer, S.Fancy Colored DiamondsIn: International Gemological Symposium Proceedings Volume, PP. 207-218.GlobalBlank
DS1985-0291
1985
Hofer, S.C.Hofer, S.C.Pink Diamonds from AustraliaGems And Gemology, Vol. 21, FALL PP. 147-155.GlobalDiamond Morphology, Colour, History, Spectral Analysis, Inclusions
DS1997-0509
1997
Hofer, S.C.Hofer, S.C.Collecting and classifying coloured diamondsAshland Pres, 1 800 451-2558, 768p. $ 300.00 United StatesGlobalBook - classification, Diamonds - coloured advert New York Diamond May p.11
DS1970-0930
1974
Hoff, T.C.F.A.Hoff, T.C.F.A.Diamanterne Fra Syd-afrika; et Populaert Foredrag Holdt I Den Naturhistoriske Forening.Unknown., Nov. 1ST, 13P.South AfricaDiamonds, History
DS1996-0637
1996
Hoffe, B.H.Hoffe, B.H.Deep seismic evidence of late Middle Proteraoic rifting beneath theKalahari, western Botswana.Memorial University of, MSc.BotswanaGeophysics - seismics, Tectonics
DS1996-0638
1996
Hoffe, B.H.Hoffe, B.H.Deep seismic evidence of late Middle Proterozoic rifting beneath theKalahari, western Botswana.Memorial University of, MSc.BotswanaGeophysics - seismics, Tectonics
DS1983-0310
1983
Hoffe, D.B.Hoffe, D.B.Book Review of Diamonds in the Desert by Olga LevinsonIndiaqua., 1983/II, No. 35, P. 155.Southwest Africa, NamibiaBook Review
DS1991-1454
1991
Hoffee, R.L.Root, S.I., Hoffee, R.L., Buckley, S.M., Hlavin, W.Details of basement tectonics, northeastern OhioGeological Society of America, Abstract Volume, Vol. 23, No. 3, March p. 57GlobalTectonics, Structure
DS201606-1077
2016
Hoffer, G.Baasner, A., Medard, E., Laporte, D., Hoffer, G.Partial melting of garnet lherzolite with water and carbon dioxide at 3 Gpa using a new melt extraction technique: implications for intraplate magmatism.Contributions to Mineralogy and Petrology, Vol. 171, 45p.MantleMagmatism

Abstract: The origin and source rocks of alkali-rich and SiO2-undersatured magmas in the Earth’s upper mantle are still under debate. The garnet signature in rare earth element patterns of such magmas suggests a garnet-bearing source rock, which could be garnet lherzolite or garnet pyroxenite. Partial melting experiments were performed at 2.8 GPa and 1345-1445 °C in a piston-cylinder using mixtures of natural lherzolite with either 0.4 wt% H2O and 0.4 wt% CO2 or 0.7 wt% H2O and 0.7 wt% CO2. Different designs of AuPd capsules were used for melt extraction. The most successful design included a pentagonally shaped disc placed in the top part of the capsule for sufficient melt extraction. The degrees of partial melting range from 0.2 to 0.04 and decrease with decreasing temperature and volatile content. All samples contain olivine and orthopyroxene. The amounts of garnet and clinopyroxene decrease with increasing degree of partial melting until both minerals disappear from the residue. Depending on the capsule design, the melts quenched to a mixture of quench crystals and residual glass or to glass, allowing measurement of the volatile concentrations by Raman spectroscopy. The compositions of the partial melts range from basalts through picrobasalts to foidites. Compared to literature data for melting of dry lherzolites, the presence of H2O and CO2 reduces the SiO2 concentration and increases the MgO concentration of partial melts, but it has no observable effect on the enrichment of Na2O in the partial melts. The partial melts have compositions similar to natural melilitites from intraplate settings, which shows that SiO2-undersaturated intraplate magmas can be generated by melting of garnet lherzolite in the Earth’s upper mantle in the presence of H2O and CO2.
DS1920-0106
1922
Hoffman, A.Hoffman, A.California Diamonds, 1922Manufacturer Jeweller., Vol. 70, MARCH 16TH. P. 522.United States, California, West CoastBlank
DS200912-0308
2008
Hoffman, C.Hoffman, C.The search for diamonds.... old story about Fipke.Wired Magazine, Dec. pp. 192-199.Canada, Northwest TerritoriesHistory
DS1999-0293
1999
Hoffman, D.Harrison, R.W., Hoffman, D., Vaughn, J.D., et al.An example of neotectonism in a continental interior - Thebes Gap, Midcontinent, United States.Tectonophysics, Vol. 305, pp. 399-417.Missouri, Illinois, MidcontinentTectonics, New Madrid Rifting
DS200412-1949
2004
Hoffman, E.Sutherland, D., Leng, D., Hoffman, E.SGH - a soil gas hydrocarbon method to locate kimberlite pipes - a case study.Geological Association of Canada Abstract Volume, May 12-14, SS14-02 p. 261.abstractTechnologyGeochemistry
DS200612-1396
2005
Hoffman, E.Sutherland, D., Hoffman, E.ACTLABS - geochromatographic vectoring of bacterial organic remnants - predictive geochemistry in exploration for kimberlites using Soil Gas Hydrocarbons (SGH)32ndYellowknife Geoscience Forum, p.74 abstractTechnologyGeochromatography
DS200712-1052
2006
Hoffman, E.Sutherland, D.A., Hoffman, E.From petroleum to diamonds - soil gas hydrocarbons - a dual purpose geochemical tool in exploration.Geological Society of America Annual Meeting, Vol. 38, 7, Nov. p. 373. abstractTechnologyGeochemistry - SGH, GCMS
DS1992-0716
1992
Hoffman, F.M.Hoffman, F.M., Tripath, V.S.A geochemical expert system prototype using object-oriented knowledge representation and a production rule systemComputers and Geosciences, Vol. 19, No. 1, pp. 53-60GlobalComputer applications, Geochemistry, AI, expert systems
DS1992-0717
1992
Hoffman, K.A.Hoffman, K.A.Dipolar reversal states of the geomagnetic field and core-mantle dynamicsNature, Vol. 359, October 29, pp. 189-MantleGeophysics, Magnetics
DS1993-0681
1993
Hoffman, K.A.Hoffman, K.A.Do flipping magnetic poles follow preferred paths?Eos, Transactions, American Geophysical Union, Vol. 74, No. 9, March 2, p. 97MantleGeophysics -paleomagnetics, VGP
DS200512-0439
2004
Hoffman, K.A.Hoffman, K.A., Singer, B.S.Regionally recurrent paleomagnetic transitional fields and mantle processes.American Geophysical Union, No. 145, pp. 233-244.MantleGeophysics - paleomagnetics
DS200812-0479
2008
Hoffman, K.A.Hoffman, K.A., Singer, B.S.Magnetic source separation in Earth's outer core.Science, Vol. 321, 5897 p. 1800.MantleGeophysics - magnetics, boundary
DS201112-1078
2011
Hoffman, K.H.Van Schijndel, V., Cornell, D.H., Hoffman, K.H., Frei, D.Three episodes of crustal development in the Rehoboth Province, Namibia.The Formation and Evolution of Africa: A synopsis of 3.8 Ga of Earth History, Geol. Soc. London Special Publ., 357, pp. 27-47.Africa, NamibiaTectonics
DS1996-0639
1996
Hoffman, K.S.Hoffman, K.S., Taylor, D.R., Schnell, R.T.3 D improves/speeds up fault plane analysisThe Leading Edge, Feb. pp. 117-122GlobalComputers, Fault planes
DS201201-0847
2011
Hoffman, P.Hoffman, P.A history of Neoproterozoic glacial geology, 1871-1997.The Geological Record of Neoproterozoic glaciations, Memoirs 2011; Vol. 36, pp. 17-37.GlobalGeomorphology - glaciation
DS201201-0848
2011
Hoffman, P.Hoffman, P., Macdonald, F.A., Halverson, G.P.Chemical sediments association with Neoproterozoic glaciation: iron formation cap carbonate, barite and phosphorite.The Geological Record of Neoproterozoic glaciations, Memoirs 2011; Vol. 36, pp. 67-80GlobalGeomorphology - geochemistry
DS201412-0364
2014
Hoffman, P.Hoffman, P.Tuzo Wilson and the acceptance of pre-Mesozoic continental drift.Canadian Journal of Earth Sciences, Vol. 51, 3, pp. 197-207.GlobalContinental drift
DS201412-0365
2014
Hoffman, P.Hoffman, P.The origin of Laurentia:Rae Craton as the backstop for Proto-Laurentian amalgamation by slab suction.Geoscience Canada, Vol. 41, 3, pp. 313-320.CanadaSubduction
DS1984-0166
1984
Hoffman, P.F.Bowring, S.A., Van schmus, W.R., Hoffman, P.F.uranium-lead (U-Pb) zircon ages from Athapuscow aulacogen, East Arm of Great Slave @northwest Territories.Canadian Journal of Earth Sciences, Vol. 21, pp. 1315-24.Northwest TerritoriesGeochronology, Alkaline Rocks
DS1985-0292
1985
Hoffman, P.F.Hoffman, P.F.Is the Cape Smith Belt ( Northern Quebec) a Klippe?Canadian Journal of Earth Sciences, Vol. 22, pp. 1361-9.Quebec, LabradorUltramafic, Crusts, Continents
DS1987-0295
1987
Hoffman, P.F.Hoffman, P.F.Continental transform tectonics: Great Slave Lake shear zone ( ca 1.9 Ga)Northwest Canada.Geology, Vol. 15, Sept. pp. 785-88.Northwest TerritoriesTectonics
DS1988-0310
1988
Hoffman, P.F.Hoffman, P.F.United plates of America, the birth of a craton: early Proterozoicassembly and growth of LaurentiaAnnual Review of Earth and Planetary Sciences, Vol. 16, pp. 543-604MidcontinentBlank
DS1989-0649
1989
Hoffman, P.F.Hoffman, P.F., Card, K.D., Davidson, A.New 1: 5, million scale geologic map of the Canadian shieldGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A39. (abstract.)CanadaShield, Tectonics
DS1990-0705
1990
Hoffman, P.F.Hoffman, P.F.Archaean continental plates: old and young mantle rootsNature, Vol. 347, No. 6288, September 6, p. 19GlobalMantle, Plates
DS1990-0706
1990
Hoffman, P.F.Hoffman, P.F.Old and young mantle rootsNature, Vol. 347, Sept. 6, pp. 19-20GlobalMantle, Roots
DS1990-0707
1990
Hoffman, P.F.Hoffman, P.F.Geological constraints on the origin of the mantle root beneath the Canadian Shield.Proceedings Transactions Royal Society. Lond., Vol. A 331, pp. 523-32.Manitoba, Alberta, Ontario, SaskatchewanCraton, Mantle - melting
DS1991-0722
1991
Hoffman, P.F.Hoffman, P.F.Did the breakout of Laurentia turn Gondwanaland inside- out?Science, Vol. 252, June 7, pp. 1409-1412Russia, Australia, AntarcticaProterozoic, Tectonics
DS1993-0682
1993
Hoffman, P.F.Hoffman, P.F., Grotzinger, J.P.Orographic precipitation, erosional unloading and tectonic styleGeology, Vol. 21, No. 3, March pp. 195-198Northwest Territories, Cordillera, Appalachia, OntarioTectonics, Orogeny, Slave Craton
DS1996-1530
1996
Hoffman, P.F.Wheeler, J.O., Hoffman, P.F., Card, K.D., Davidson, et al.Geological map of CanadaGeological Survey of Canada, CD ROM $ 130.00CanadaMap - ad, Geological map of Canada
DS1996-1531
1996
Hoffman, P.F.Wheeler, J.O., Hoffman, P.F., Card, K.D., Davidson, A.Geological map of Canada... on CD-ROMGeological Survey of Canada, Map 1860 A CD-ROM $ 130.00CanadaGeological Map, CD-ROM version
DS1996-1532
1996
Hoffman, P.F.Wheeler, J.O., Hoffman, P.F., Card, K.D., Davidson, A. etc.Geological map of Canada... carbonatites and kimberlites featured along with geology etc.Geological Survey of Canada, Map 1860A, 1: 5, 000, 000 $ 40.00CanadaMap, Geology -with kimberlites plotted
DS1998-0627
1998
Hoffman, P.F.Hoffman, P.F.The Rodinia hypothesis and the birth of GondwanaJournal of African Earth Sciences, Vol. 27, 1A, p. 111. AbstractGondwanaGeodynamics
DS1998-0628
1998
Hoffman, P.F.Hoffman, P.F., Kaufman, A.J., Halverson, G.P.Comings and goings of global glaciations on a Neoproterozoic tropical platform in Namibia.Gsa Today, Vol. 8, No. 5, May pp. 1-9.NamibiaGeomorphology, Glacial deposits.... not specific to diamonds
DS1999-0311
1999
Hoffman, P.F.Hoffman, P.F.The break up of Rodinia, birth of Gondwana, true polar wander and the snowball Earth.Journal of African Earth Sciences, Vol. 28, No. 1, pp. 17-33.GlobalTectonics - Craton
DS2002-0731
2002
Hoffman, P.F.Hoffman, P.F., Schrag, D.P.The snowball Earth hypothesis: testing the limits of global changeTerra Nova, Vol. 14, No. 3, June pp. 129-55.Canada, Namibia, AustraliaGeomorphology, Glaciation, Carbon isotopes, iron formation
DS200612-0593
2005
Hoffman, P.F.Hoffman, P.F.28th. De Beers Alex du Toit memorial lecture, 2004. On cryogenian (Neoproterozoic) ice sheet dynamics and the limitations of the glacial sedimentary record.South African Journal of Geology, Vol. 108, pp. 557-577.Africa, Angola, Democratic Republic of CongoSnowball Earth, paleomagnetism, cratons
DS201201-0849
2011
Hoffman, P.F.Hoffman, P.F., Halverson, G.P.Neoproterozoic glacial record in the Mackenzie Mountains, northern Canadian Cordillera.The Geological Record of Neoproterozoic glaciations, Memoirs 2011; Vol. 36, pp. 397-412.CanadaGeomorphology
DS201312-0395
2013
Hoffman, P.F.Hoffman, P.F.The Great Oxidation event and a Siderian Snowball Earth: MIF based correlation of Paleoproterozoic glaciations.Chemical Geology, Vol. 362, pp. 143-156.MantleOxidation event
DS201809-2028
2018
Hoffman, P.F.Gong, Z., Xu, X., Evans, D.A.D., Hoffman, P.F., Mitchell, R.N., Bleeker, W.Paleomagnetism and rock magnetism of the ca. 1.87 Ga Pearson Formation, Northwest Territories, Canada: a test of vertical axis rotation within the Great Slave Basin.Precambrian Research , Vol. 305C, pp. 295-309.Canada, Northwest Territoriesgeophysics

Abstract: A geometrically quantitative plate-kinematic model, based on paleomagnetism, for the initial assembly of Laurentia has taken form in the past few decades. Within this framework, there remains but one problematic interval of data predominantly from the Slave craton, which is the 1.96-1.87?Ga Coronation apparent polar wander path (APWP). The Coronation APWP shows large (~110°) back-and-forth oscillations that are difficult to explain in terms of plate motion. Nonetheless, poles from the Coronation APWP have been incorporated in various paleogeographic reconstructions of Laurentia and the supercontinent Nuna, pointing to the importance of testing its veracity. In this study, we conducted a detailed paleomagnetic and rock magnetic study of the ca. 1.87?Ga Pearson Formation, East Arm of Great Slave Lake, Northwest Territories, Canada. Our results show that Pearson Formation yields a characteristic remanent magnetization carried by single-domain or small pseudo-single-domain magnetite. The age of the magnetization is constrained to be older than Paleoproterozoic deformation and is interpreted as primary. Paleomagnetic declinations reveal a one-to-one correlation with local structural attitudes, indicating that some small blocks in the fold belt likely experienced significant (~60°) vertical-axis rotations, presumably related to large dextral displacements along the McDonald Fault system. Alternative explanations, such as true polar wander or a non-dipole magnetic field, are considered less parsimonious for the data presented here. It is suspected that some existing Christie Bay Group poles (the Stark and Tochatwi Formations), which were sampled in areas with anomalous structural attitudes and differ from time-equivalent poles obtained from areas of the Slave craton far from major transcurrent faults, may similarly suffer from vertical-axis rotation. We suggest further study before using possibly rotated Christie Bay Group poles for paleogeographic reconstructions.
DS201907-1549
2019
Hoffman, P.F.Hoffman, P.F.Big Time. Proterozoic Eon … Annual Reviews of Earth and Planetary Sciences, Vol. 47, pp. 2-19.Globalplate tectonics

Abstract: The Proterozoic Eon was once regarded as the neglected middle half of Earth history. The name refers to early animals, but they did not appear until the eon (2.5-0.54 Ga) was nearly over. Eukaryotic cells and sexual reproduction evolved much earlier in the eon, as did chloroplasts. Molecular dioxygen, the presence of which altered the geochemical behavior of nearly every element essential to life, rose from negligible to near-modern levels, and then plummeted before rising fitfully again. Plate tectonics took on a modern form, and two supercontinents, Nuna and Rodinia, successively congregated and later dispersed. Climate regulatory failures, i.e., Snowball Earth, appear to be a uniquely Proterozoic phenomenon, having occurred twice in rapid succession near the end of the eon (from 717 to 660 Ma and from 650 to 635 Ma) and arguably once near its beginning (ca. 2.43 Ga). Dynamic sea glaciers covered Snowball Earth oceans from pole to pole, and equatorial sublimation drove slow-moving ice sheets on land. Ultimately, the gradual accumulation of CO2 triggered rapid deglaciation and transient greenhouse aftermaths. Physically based and geologically tested, Neoproterozoic Snowball Earth appears to have molecular legacies in ancient bitumens and modern organisms. This is the story of my love affair with an eon that is now a little less neglected.
DS202005-0737
2019
Hoffman, P.F.Hoffman, P.F.Big Time: Proterozoic Eon.Annual Review of Earth and Planetary Sciences, Vol. 47, pp. 1-17. pdfMantleplate tectonics

Abstract: The Proterozoic Eon was once regarded as the neglected middle half of Earth history. The name refers to early animals, but they did not appear until the eon (2.5-0.54 Ga) was nearly over. Eukaryotic cells and sexual reproduction evolved much earlier in the eon, as did chloroplasts. Molecular dioxygen, the presence of which altered the geochemical behavior of nearly every element essential to life, rose from negligible to near-modern levels, and then plummeted before rising fitfully again. Plate tectonics took on a modern form, and two supercontinents, Nuna and Rodinia, successively congregated and later dispersed. Climate regulatory failures, i.e., Snowball Earth, appear to be a uniquely Proterozoic phenomenon, having occurred twice in rapid succession near the end of the eon (from 717 to 660 Ma and from 650 to 635 Ma) and arguably once near its beginning (ca. 2.43 Ga). Dynamic sea glaciers covered Snowball Earth oceans from pole to pole, and equatorial sublimation drove slow-moving ice sheets on land. Ultimately, the gradual accumulation of CO2 triggered rapid deglaciation and transient greenhouse aftermaths. Physically based and geologically tested, Neoproterozoic Snowball Earth appears to have molecular legacies in ancient bitumens and modern organisms. This is the story of my love affair with an eon that is now a little less neglected.
DS1990-0708
1990
Hoffman, S.Hoffman, S.Recognizing sampling problemsExplore, No. 67, January pp. 10, 12GlobalSampling, Assays-ore reserves
DS1994-0786
1994
Hoffman, S.Housman, V.E., Hoffman, S.A summary and analysis of EPA's mining site visitsAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, Meeting held Albuquerque Feb. 14-17th, No. 94-128, 6pUnited StatesMining legislation -environmental, Site visits, EPA.
DS1998-0733
1998
HoffmannKennedy, 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
DS1996-1379
1996
Hoffmann, A.W.Stolz, A.J., Jochun, K.P., Spettel, B., Hoffmann, A.W.Fluid and melt related enrichment in the subarc mantle: evidence from Niobium-Tantalum variations in island arc basaltsGeology, Vol. 24, No. 7, July, pp. 587-590MantleSubarc subduction, Basalts
DS1992-0718
1992
Hoffmann, H.J.Hoffmann, H.J.New Precambrian time scale: commentsEpisodes, Vol. 15, No. 2, June pp. 122-123GlobalPrecambrian, Time scale
DS200712-0445
2007
Hoffmann, J.E.Hoffmann, J.E., Munker, C., Polat, A., Mezger, K.Evidence for Hadean mantle depletion in the sources of ~ 3.75 Ga subduction related rocks, Isua, SW Greenland.Plates, Plumes, and Paradigms, 1p. abstract p. A410.Europe, GreenlandSubduction - boninites
DS201012-0401
2009
Hoffmann, J.E.Konig, S., Munker, C., Schuth, S., Luguet, A., Hoffmann, J.E., Kuduon, J.Boninites as windows into trace element mobility in subduction zones.Geochimica et Cosmochimica Acta, Vol. 74, 2, pp. 684-704.MantleSubduction
DS201112-0439
2011
Hoffmann, J.E.Hoffmann, J.E., Munker, C., Naeraa, T., Rosing, M.T., Herwartz, D., Garbe-Schonberg, Svahnberg, H.Mechanisms of Archean crust formation inferred from high precision HFSE systematics in TTGs.Geochimica et Cosmochimica Acta, Vol. 75, 15, pp. 4157-4178.Europe, GreenlandMantle melting
DS201710-2232
2017
Hoffmann, J.E.Hoffmann, J.E.Oxygenation by a changing crust.Nature Geoscience, Vol. 10, 10, pp. 713-714.Mantlemetasomatism

Abstract: Serpentine minerals in Earth's early upper continental crust suppressed atmospheric oxygen levels until the upper crust became granitic.
DS201805-0986
2018
Hoffmann, J.E.van de Locht, J., Hoffmann, J.E., Li, C., Wang, Z., Becker, H., Rosing, M.T., Kleinschrodt, R., Munker, C.Earth's oldest mantle peridotites show entire record of late accretion.Geology, Vol. 46, 3, pp. 199-202.Europe, Greenlandperidotites

Abstract: An important issue in Earth’s earliest history is the timing and mixing history of the late accreted material that supplied highly siderophile elements to Earth’s mantle after core segregation. Previously, constraints on ancient mantle processes could only be obtained indirectly from mantle-derived magmas such as basalts or komatiites. Relics of Eoarchean (older than 3.8 Ga) mantle were proposed to occur within the Eoarchean terrains of western Greenland. Here we provide geochemical evidence, including combined platinum group element (PGE) and Re-Os isotope data, showing that modern mantle-like peridotites occur at two localities in southwest Greenland. Rhenium-depletion model ages of these peridotites are mostly of Eoarchean age, in accord with U-Pb zircon ages of crosscutting granitoid intrusives. PGE abundances and patterns are similar to those of modern depleted mantle peridotites. For the first time, such patterns provide conclusive evidence for preservation of Eoarchean depleted mantle rocks that are clearly distinguishable from magmatic cumulates or komatiites. Abundances of Os, Ir, and Ru combined with Os isotope compositions in the Greenland peridotites reveal that primitive late accreted material appears to have been efficiently mixed into the sampled mantle domains by Eoarchean time.
DS201811-2586
2018
Hoffmann, J.E.Kroner, A., Nagel, T.J., Hoffmann, J.E., Liu, X., Wong, J., Hegner, E., Xie, H., Kasper, U., Hofmann, A., Liu, D.High temperature metamorphism and crustal melting at ca. 3.2 Ga in the eastern Kaapvaal craton.Precambrian Research, Vol. 317, pp. 101-116.Africa, South Africacraton

Abstract: The question of whether high-grade metamorphism and crustal melting in the early Archaean were associated with modern-style plate tectonics is a major issue in unravelling early Earth crustal evolution, and the eastern Kaapvaal craton has featured prominently in this debate. We discuss a major ca. 3.2?Ga tectono-magmatic-metamorphic event in the Ancient Gneiss Complex (AGC) of Swaziland, a multiply deformed medium- to high-grade terrane in the eastern Kaapvaal craton consisting of 3.66-3.20?Ga granitoid gneisses and infolded greenstone remnants, metasedimentary assemblages and mafic dykes. We report on a 3.2?Ga granulite-facies assemblage in a metagabbro of the AGC of central Swaziland and relate this to a major thermo-magmatic event that not only affected the AGC but also the neighbouring Barberton granitoid-greenstone terrane. Some previous models have related the 3.2?Ga event in the eastern Kaapvaal craton to subduction processes, but we see no evidence for long, narrow belts and metamorphic facies changes reflecting lithospheric suture zones, and there is no unidirectional asymmetry in the thermal structure across the entire region from Swaziland to the southern Barberton granite-greenstone terrane as is typical of Phanerozoic and Proterozoic belts. Instead, we consider an underplating event at ca. 3.2?Ga, giving rise to melting in the lower crust and mixing with mantle-derived under- and intraplated mafic magma to generate the voluminous granitoid assemblages now observed in the AGC and the southern Barberton terrane. This is compatible with large-scale crustal reworking during a major thermo-magmatic event and the apparent lack of a mafic lower crust in the Kaapvaal craton as shown by seismic data.
DS201012-0346
2010
Hoffmann, K-H.Kasemann, S.A., Prave, A.R., Fallick, A.E., Hawkesworth, C.J., Hoffmann, K-H.Neoproterozoic ice ages, boron isotopes, and ocean acidification: implications for a snowball Earth.Geology, Vol. 38, 9, pp. 775-778.MantleSnowball Earth
DS201412-0367
2014
Hoffmann, K-H.Hofmann, M., Linnemann, U., Hoffmann, K-H., Gerdes, A., Eckelmann, K., Gartner, A.The Namuskluft and Dreigratberg sections in southern Namibia ( Kalahari Craton, Gariep Belt): a geological history of Neoproterozoic rifting and recycling of cratonic crust during the dispersal of Rodinia until the amalgamation of Gondwana.International Journal of Earth Sciences, Vol. 103, pp. 1187-1202.Africa, NamibiaGeochronology
DS2003-0860
2003
Hoffman-Setka, D.Mahan, K.H., Hoffman-Setka, D., Williams, M.L., Kopf, C.F.Contrasting lithotectonic domain boundaries within a deep crustal exposure, northernGeological Association of Canada Annual Meeting, Abstract onlySaskatchewanTectonics
DS200412-1199
2003
Hoffman-Setka, D.Mahan, K.H., Hoffman-Setka, D., Williams, M.L., Kopf, C.F.Contrasting lithotectonic domain boundaries within a deep crustal exposure, northern Saskatchewan, western Canadian shield.Geological Association of Canada Annual Meeting, Abstract onlyCanada, SaskatchewanTectonics
DS1950-0218
1955
Hoffmeister, C.Hoffmeister, C.Sterne Ueber den SteppeLeipzig: Brockhaus, Southwest Africa, NamibiaDiamond Fiction, Kimberley
DS1999-0465
1999
HoffowerMcMillan, M.E., Heller, P.L., Hoffower, BlackstoneIs there a northern boundary of the Colorado Plateau?Geological Society of America (GSA), Vol. 31, No. 7, p. 187. abstract.Alberta, WyomingTectonics
DS1989-0650
1989
Hofland, G.S.Hofland, G.S., Barton, C.C.FREQFIT: a computer program which performs numerical regression and statistical chi-squared goodness of fit analysisUnited States Geological Survey (USGS) Open File, No. 89-0139, 62p. $ 10.00GlobalComputer, Program -FREQFIT.
DS1996-0018
1996
Hofman, A.Allegre, C.J., Hofman, A., O'Nions, K.The argon constraints on mantle structureGeophysical Research. Letters, Vol. 23, No. 24, Dec. 1, pp. 3555-58.MantleGeochronology
DS2002-0384
2002
Hofman, A.Dirks, P.H.G.M., Jelsma, H.A., Hofman, A.Thrust related accretion of an Archean greenstone belt in the midlands of ZimbabweJournal of Structural Geology, Vol.24, 11, Nov. pp. 1707-27.ZimbabweTectonics
DS201412-0220
2014
Hofman, A.Eiler, J.M., Berquist, B., Bourg, I., Cartigny, P., Farquhar, J., Gagnon, A., Guo, W., Halevy, I., Hofman, A., larson, T.E., Levin, N., Schauble, E.A., Stolper, D.Frontiers of stable isotope geoscience.Chemical Geology, Vol. 372, pp. 119-143.TechnologyReview of isotopes
DS201710-2215
2017
Hofman, A.Bolhar, R., Hofman, A., Kemp, A.I.S., Whitehouse, M.J., Wind, S., Kamber, B.S.Juvenile crust formation in the Zimbabwean Craton deduced from the O-Hf isotopic record 3.8-3.1 Ga detrital zircons.Geochimica et Cosmochinica Acta, Vol. 215, pp. 432-446.Africa, Zimbabwecraton

Abstract: Hafnium and oxygen isotopic compositions measured in-situ on U-Pb dated zircon from Archaean sedimentary successions belonging to the 2.9–2.8 Ga Belingwean/Bulawayan groups and previously undated Sebakwian Group are used to characterize the crustal evolution of the Zimbabwe Craton prior to 3.0 Ga. Microstructural and compositional criteria were used to minimize effects arising from Pb loss due to metamorphic overprinting and interaction with low-temperature fluids. 207Pb/206Pb age spectra (concordance >90%) reveal prominent peaks at 3.8, 3.6, 3.5, and 3.35 Ga, corresponding to documented geological events, both globally and within the Zimbabwe Craton. Zircon d18O values from +4 to +10‰ point to both derivation from magmas in equilibrium with mantle oxygen and the incorporation of material that had previously interacted with water in near-surface environments. In eHf-time space, 3.8–3.6 Ga grains define an array consistent with reworking of a mafic reservoir (176Lu/177Hf ~0.015) that separated from chondritic mantle at ~3.9 Ga. Crustal domains formed after 3.6 Ga depict a more complex evolution, involving contribution from chondritic mantle sources and, to a lesser extent, reworking of pre-existing crust. Protracted remelting was not accompanied by significant mantle depletion prior to 3.35 Ga. This implies that early crust production in the Zimbabwe Craton did not cause complementary enriched and depleted reservoirs that were tapped by later magmas, possibly because the volume of crust extracted and stabilised was too small to influence (asthenospheric) mantle isotopic evolution. Growth of continental crust through pulsed emplacement of juvenile (chondritic mantle-derived) melts, into and onto the existing cratonic nucleus, however, involved formation of complementary depleted subcontinental lithospheric mantle since the early Archaean, indicative of strongly coupled evolutionary histories of both reservoirs, with limited evidence for recycling and lateral accretion of arc-related crustal blocks until 3.35 Ga.
DS2001-0952
2001
Hofman, A.W.Puchtel, I.S., Brugmann, G.E., Hofman, A.W.1870's enriched domain in an Archean mantle plume: evidence from 2.8 Ga komatiites of the Kostomuksha GSEarth and Planetary Science Letters, Vol. 186, No. 3-4, Apr. 15, pp. 513-26.Baltic ShieldPlume - geochronology - not specific to diamonds
DS2003-0595
2003
Hofman, A.W.Hofman, A.W.Just add water.. new model why upper mantle is depleted of many trace elementsNature, No. 6953, September 4, pp.24-25.MantleGeochemistry, convection, molten filter, discontinuity
DS200412-0841
2003
Hofman, A.W.Hofman, A.W.Just add water.. new model why upper mantle is depleted of many trace elements.Nature, No. 6953, September 4, pp.24-25.MantleGeochemistry, convection, molten filter, discontinuity
DS201312-0561
2014
Hofman, A.W.Ma, L., Jiang, S-Y., Hofman, A.W., Dai, B-Z., Hou, M-L., Zhao, K-D, Chen, L-H., Jiang, Y.H.Lithospheric and asthenospheric sources of lamprophyres in the Jiadong Peninsula: a consequence of rapid lithospheric thinning beneath the North Chin a craton?Geochimica et Cosmochimica Acta, Vol. 124, pp. 250-271.ChinaLamprophyre
DS201808-1724
2018
Hofmann, A.Avice, G., Marty, B., Burgess, R., Hofmann, A., Philippot, P., Zahnle, K., Zakharov, D.Evolution of atmospheric xenon and other noble gases inferred from Archean to Paleoproterozoic rocks.Geochimica et Cosmochimica Acta, Vol. 232, pp. 82-100.Mantlegeochemistry

Abstract: We have analyzed ancient atmospheric gases trapped in fluid inclusions contained in minerals of Archean (3.3?Ga) to Paleozoic (404?Ma) rocks in an attempt to document the evolution of the elemental composition and isotopic signature of the atmosphere with time. Doing so, we aimed at understanding how physical and chemical processes acted over geological time to shape the modern atmosphere. Modern atmospheric xenon is enriched in heavy isotopes by 30-40‰ u-1 relative to Solar or Chondritic xenon. Previous studies demonstrated that, 3.3?Ga ago, atmospheric xenon was isotopically fractionated (enriched in the light isotopes) relative to the modern atmosphere, by 12.9?±?1.2 (1s) ‰ u-1, whereas krypton was isotopically identical to modern atmospheric Kr. Details about the specific and progressive isotopic fractionation of Xe during the Archean, originally proposed by Pujol et al. (2011), are now well established by this work. Xe isotope fractionation has evolved from 21‰ u-1 at 3.5?Ga to 12.9‰ u-1 at 3.3?Ga. The current dataset provides some evidence for stabilization of the Xe fractionation between 3.3 and 2.7?Ga. However, further studies will be needed to confirm this observation. After 2.7?Ga, the composition kept evolving and reach the modern-like atmospheric Xe composition at around 2.1?Ga ago. Xenon may be the second atmospheric element, after sulfur, to show a secular isotope evolution during the Archean that ended shortly after the Archean-Proterozoic transition. Fractionation of xenon indicates that xenon escaped from Earth, probably as an ion, and that Xe escape stopped when the atmosphere became oxygen-rich. We speculate that the Xe escape was enabled by a vigorous hydrogen escape on the early anoxic Earth. Organic hazes, scavenging isotopically heavy Xe, could also have played a role in the evolution of atmospheric Xe. For 3.3?Ga-old samples, Ar-N2 correlations are consistent with a partial pressure of nitrogen (pN2) in the Archean atmosphere similar to, or lower than, the modern one, thus requiring other processes than a high pN2 to keep the Earth's surface warm despite a fainter Sun. The nitrogen isotope composition of the atmosphere at 3.3?Ga was already modern-like, attesting to inefficient nitrogen escape to space since that time.
DS201811-2586
2018
Hofmann, A.Kroner, A., Nagel, T.J., Hoffmann, J.E., Liu, X., Wong, J., Hegner, E., Xie, H., Kasper, U., Hofmann, A., Liu, D.High temperature metamorphism and crustal melting at ca. 3.2 Ga in the eastern Kaapvaal craton.Precambrian Research, Vol. 317, pp. 101-116.Africa, South Africacraton

Abstract: The question of whether high-grade metamorphism and crustal melting in the early Archaean were associated with modern-style plate tectonics is a major issue in unravelling early Earth crustal evolution, and the eastern Kaapvaal craton has featured prominently in this debate. We discuss a major ca. 3.2?Ga tectono-magmatic-metamorphic event in the Ancient Gneiss Complex (AGC) of Swaziland, a multiply deformed medium- to high-grade terrane in the eastern Kaapvaal craton consisting of 3.66-3.20?Ga granitoid gneisses and infolded greenstone remnants, metasedimentary assemblages and mafic dykes. We report on a 3.2?Ga granulite-facies assemblage in a metagabbro of the AGC of central Swaziland and relate this to a major thermo-magmatic event that not only affected the AGC but also the neighbouring Barberton granitoid-greenstone terrane. Some previous models have related the 3.2?Ga event in the eastern Kaapvaal craton to subduction processes, but we see no evidence for long, narrow belts and metamorphic facies changes reflecting lithospheric suture zones, and there is no unidirectional asymmetry in the thermal structure across the entire region from Swaziland to the southern Barberton granite-greenstone terrane as is typical of Phanerozoic and Proterozoic belts. Instead, we consider an underplating event at ca. 3.2?Ga, giving rise to melting in the lower crust and mixing with mantle-derived under- and intraplated mafic magma to generate the voluminous granitoid assemblages now observed in the AGC and the southern Barberton terrane. This is compatible with large-scale crustal reworking during a major thermo-magmatic event and the apparent lack of a mafic lower crust in the Kaapvaal craton as shown by seismic data.
DS1989-0713
1989
Hofmann, A.W.Jochum, K.P., Hofmann, A.W.Fingerprinting geological materials using SSMS- commentChemical Geology, Vol. 75, No. 3, March 30, pp. 249-252GlobalGeochemistry, SSMS
DS1992-0756
1992
Hofmann, A.W.Ionov, D.A., Hofmann, A.W.Metasomatism induced melting in mantle xenolithsEos, Transactions, Annual Fall Meeting Abstracts, Vol. 73, No. 43, October 27, abstracts p. 657MantleMetasomatism, Xenoliths
DS1992-1470
1992
Hofmann, A.W.Stein, M., Hofmann, A.W.Fossil plume head beneath the Arabian lithosphere?Earth and Planetary Science Letters, Vol. 114, No. 1, December pp. 193-210GlobalHot springs, Lithosphere
DS1993-1527
1993
Hofmann, A.W.Stein, M., Hofmann, A.W.Fossil plume head beneath the Arabian lithosphereEarth and Planetary Science Letters, Vol. 114, pp. 193-209.GlobalMantle plumes, Tectonics, geochemistry
DS1994-0304
1994
Hofmann, A.W.Christensen, U.R., Hofmann, A.W.Segregation of subducted oceanic crust in the convecting mantleJournal of Geophysical Research, Vol. 99, No. B 10, Oct. 10, pp. 19, 867-884.MantleConvective
DS1994-0780
1994
Hofmann, A.W.Hofmann, A.W., Stein, M.Episodic crustal growth and mantle evolutionMineralogical Magazine, Vol. 58A, pp. 420-421.. AbstractMantleGeodynamics
DS1994-0808
1994
Hofmann, A.W.Ionov, D.A., Hofmann, A.W., Shimizu, N.Metasomatism induced melting in mantle xenoliths from MongoliaJournal of Petrology, Vol. 35, No. 3, June pp. 753-786.GlobalXenoliths
DS1994-1374
1994
Hofmann, A.W.Peucker-Ehrebrink, B., Hofmann, A.W., Hart, S.R.Hydrothermal lead transfer from mantle to continental crust: the role of metalliferous sedimentsEarth and Planetary Science Letters, Vol. 125, pp. 129-142MantleHydrothermal, Alteration
DS1994-1686
1994
Hofmann, A.W.Stein, M., Hofmann, A.W.Mantle plumes and episodic crustal growthNature, Vol. 372, No. 6501, Nov. 3, pp. 63-68.MantleCrustal growth
DS1994-1687
1994
Hofmann, A.W.Stein, M., Hofmann, A.W.Mantle plumes and episodic crustal growthNature, Vol. 372, No. 6501, Nov. 3, pp. 63-67MantlePlumes
DS1995-0021
1995
Hofmann, A.W.Allegre, C.J., Poirier, J.P., Hofmann, A.W.The chemical composition of the earthEarth and Planetary Science Letters, Vol. 134, No. 3-4, Sept. 1, pp. 515-526.GlobalGeochemistry, Composition -chemical
DS1995-0299
1995
Hofmann, A.W.Chauvel, C., Goldstein, S.L., Hofmann, A.W.Hydration and dehydration of oceanic crust controls lead evolution in themantle.Chemical Geology, Vol. 126, pp. 65-75.MantleGeochronology
DS1995-0851
1995
Hofmann, A.W.Ionov, D.A., Hofmann, A.W.Niobium and Tantalum rich mantle amphiboles and micas: implications for subduction related metasomatic trace elements.Earth and Planetary Science Letters, Vol. 131, No. 3-4, April pp. 341-356.MantleSubduction, Metasomatism
DS1997-0510
1997
Hofmann, A.W.Hofmann, A.W.Mantle geochemistry: the message from oceanic volcanismNature, Vol. 385, Jan. 16, pp. 219-229.MantleGeochemistry, Oceanic volcanism - review
DS1997-0511
1997
Hofmann, A.W.Hofmann, A.W.Early evolution of continentsScience, Vol. 275, Jan. 24, pp. 498-9MantleGeochemistry, Review
DS1997-0560
1997
Hofmann, A.W.Jochum, K.P., Hofmann, A.W.Constraints on earth evolution from antimony in mantle derived rocksChemical Geology, Vol. 139, pp. 39-49MantleChondrite, Basalts
DS1998-0629
1998
Hofmann, A.W.Hofmann, A.W.Geochemical reservoirs and whole mantle convectionMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 640-1.MantleCore-mantle boundary, Geochemistry
DS1999-0571
1999
Hofmann, A.W.Puchtel, I.S., Brugmann, G.E., Hofmann, A.W.Precise Re Os mineral isochron and lead neodymium Os isotope systematics of a mafic ultramafic sill in 2.0 Ga OnegaEarth and Planetary Science Letters, Vol. 170, No. 4, July 30, pp. 447-62.Baltic shieldGeochronology, Onega plateau
DS1999-0572
1999
Hofmann, A.W.Puchtel, I.S., Brugmann, G.E., Hofmann, A.W.Precise Re Os mineral isochron and lead neodymium Os isotope systematics of mafic ultramafic sill in 2.0 Ga OnegaEarth and Planetary Science Letters, Vol. 170, No. 4, July 30, pp. 447-62.Baltic ShieldGeochronology, Onega Plateau
DS2002-1271
2002
Hofmann, A.W.Polat, A., Hofmann, A.W., Rosing, M.T.Boninite like volcanic rocks in the 3.7-3.8 Ga Isua greenstone belt: geochemical evidence for intra oceanicChemical Geology, Vol. 184, No.3-4, pp.231-54.GreenlandSubduction zone - Early Earth
DS200412-1617
2004
Hofmann, A.W.Rampone, E., Romairone, A., Hofmann, A.W.Contrasting bulk and mineral chemistry in depleted mantle peridotites: evidence for reactive porous flow.Earth and Planetary Science Letters, Vol. 218, 3-4, Feb. 15, pp. 491-506.Europe, AlpsMineral chemistry - not specific to diamonds
DS200512-0235
2005
Hofmann, A.W.Dobolev, A.V., Hofmann, A.W., Sobolev, S.V., Nikogosian, I.K.An olivine free mantle source of Hawaiian shield basalts.Nature, No. 7033, March 31, pp. 590-597.Mantle, HawaiiGeochemistry
DS200512-1058
2005
Hofmann, A.W.Stracke, A., Hofmann, A.W., Hart, S.R.FOZO, HIMU and the rest of the mantle zoo.Geochemistry, Geophysics, Geosystems: G3, Vol. 6, doi:10.1029/2004 GC000824MantleUHP
DS200512-1093
2005
Hofmann, A.W.Tolstikhin, I., Hofmann, A.W.Early crust on top of the Earth's core.Physics of the Earth and Planetary Letters, Vol. 148, 2-4, Feb. pp. 109-130.MantleGeochemistry, core mantle boundary, rare gases, REE
DS200612-0623
2006
Hofmann, A.W.Ionov, D.A., Hofmann, A.W., Merlet, C., Gurenko, A.A., Hellebrand, E., Montagnac, G., Gillet, P., PrikhodkoDiscovery of whitlockite in mantle xenoliths: inferences for water and halogen poor fluid and trace element residence in the terrestrial upper mantle.Earth and Planetary Science Letters, Vol. 244, 1-2, Apr. 15, pp. 201-207.MantleXenolith - mineralogy
DS200612-1433
2005
Hofmann, A.W.Tolstikhin, I.N., Kramers, J.D., Hofmann, A.W.A chemical Earth model with whole mantle convection: the importance of a core mantle boundary layer 'D' and its early formation.Chemical Geology, Vol. 226, 3-4, pp. 79-99.MantleConvection, model
DS200612-1554
2006
Hofmann, A.W.Xiao, Y., Sun, W., Hoefs, J., Simon, K., Zhang, Z., Li, S., Hofmann, A.W.Making continental crust through slab melting: constraints from niobium tantalum fractionation in UHP metamorphic rutile.Geochimica et Cosmochimica Acta, Vol. 70, 18, Sept. 15, pp. 4770-47082.ChinaDabie Sulu - eclogites - UHP
DS200712-0173
2007
Hofmann, A.W.Chen, L-H., Jiang, S-Y., Hofmann, A.W., Jovanovic, Z., Xie, L-W., Zhou, X-H.Are peridotite xenoliths in Mesozoic plutons inherited from Paleozoic kimberlites?Plates, Plumes, and Paradigms, 1p. abstract p. A166.ChinaNorth China Craton
DS200712-0305
2007
Hofmann, A.W.Farnetani, C.G., Hofmann, A.W.Dynamics and internal structure of a mantle plume conduit.Plates, Plumes, and Paradigms, 1p. abstract p. A268.MantleHotspots
DS200712-0446
2007
Hofmann, A.W.Hofmann, A.W., Goldstein, S.L., Class, C.Is D' a low mu reservoir?Plates, Plumes, and Paradigms, 1p. abstract p. A410.MantleMelting
DS200712-0464
2007
Hofmann, A.W.Ionov, D.A., Hofmann, A.W.Depth of formation of subcontinental off-craton peridotites.Earth and Planetary Science Letters, Vol. 261, 3-4, pp. 620-634.MantlePeridotite
DS200812-0339
2008
Hofmann, A.W.Farnetani, C.G., Hofmann, A.W.Length scales of isotope heterogeneities: from D' to a mantle plume conduit.Goldschmidt Conference 2008, Abstract p.A257.MantlePlume
DS200812-0480
2008
Hofmann, A.W.Hofmann, A.W.Mantle myths, mantle reservoirs, and databases.Goldschmidt Conference 2008, Abstract p.A384.MantleGeochemistry
DS200812-1091
2008
Hofmann, A.W.Sobolev, A.V., Hofmann, A.W., Brugmann, G., Batanova, V.G., Kuzmin, D.V.A quantitative link between recycling and osmium isotopes.Science, Vol. 321, 5888, July 25, p. 536.MantleSubduction
DS200912-0212
2009
Hofmann, A.W.Farnetani, C.G., Hofmann, A.W.Dynamics and internal structure of a lower mantle plume conduit.Earth and Planetary Science Letters, Vol. 282, 1-4, pp. 314-322.MantleGeodynamics
DS201605-0863
2016
Hofmann, A.W.Ma, L., Jiang, S-Y., Hofmann, A.W., Xu, Y-G, Dai, B-Z., Hou, M-L.Rapid lithospheric thinning of North Chin a craton: new evidence from Cretaceous mafic dikes in the Jiaodong Peninsula.Chemical Geology, Vol. 432, pp. 1-15.ChinaDikes

Abstract: The North China Craton is a classic case for the destruction of an ancient craton, in that it records the loss of more than 100 km of ancient refractory lithospheric mantle during the late Mesozoic and early Cenozoic. However, the mechanisms for this lithospheric thinning remain controversial in large part due to the lack of any systematic investigations of the Mesozoic asthenospheric mantle via its derived mafic rocks, which are key to understand the thinning processes. In this paper, we present detailed zircon U-Pb geochronology, elemental geochemistry, and Sr-Nd-Hf isotopic data for lamprophyres and diabase-porphyries of the Jiaodong Peninsula, in the eastern North China Craton in order to place constraints on models for lithospheric thinning. Our results show that the lamprophyres and diabase-porphyries are derived from the convective asthenospheric mantle via different degrees of partial melting, and that this mantle source was previously modified by carbonatitic liquids. Zircon LA-ICP-MS U-Pb dating suggests an emplacement age for these rocks of 123-121 Ma, the earliest evidence for asthenospherically-derived melts in the Jiaodong Peninsula so far. This emplacement age indicates that the thickness of the lithosphere in the Jiaodong Peninsula was relatively thin at that time. Co-occurrence of the asthenospheric and lithospheric mantle-derived mafic rocks as well as high-Mg adakites record a rapid transition from lithospheric to asthenospheric mantle sources, indicating that the lithosphere beneath the Jiaodong Peninsula was rapidly detached just prior to ca. 120 Ma. Lithospheric thinning of the North China Craton may have been initiated from the Jiaodong Peninsula and Bohai Sea and then propagated towards the interior of the craton.
DS1990-0709
1990
Hofmann, H.J.Hofmann, H.J.Precambrian time units and nomenclature- the geon conceptGeology, Vol. 18, No. 4, April pp. 340-341GlobalPrecambrian time units, Geon-large scale time unit
DS1999-0312
1999
Hofmann, H.J.Hofmann, H.J.Geons and geons... units of time of 100 my intervals... discussionGeology, Vol. 27, No. 9, Sept. pp. 855-6.GlobalGeochronology
DS201112-0440
2011
Hofmann, M.Hofmann, M., Linnemann, U., Rai, V., Becker, S., Gartner, A., Sagawe, A.The India and South Chin a cratons at the margin of Rodinia - synchronous Neoproterozoic magmatism revealed by LA-ICP-MS zircon analyses.Lithos, In press available 65p.India, ChinaMagmatism
DS201312-0047
2013
Hofmann, M.Bader, T., Ratschbacher, L., Franz, L., Yang, Z., Hofmann, M., Linneman, U., Yuan, H.The heart of Chin a revisited. 1. Proterozoic tectonics of the Qin Mountains in the core of supercontinent Rodinia.Tectonics, Vol. 32, 3, pp. 661-687.ChinaMagmatism - Dabie orogen
DS201412-0271
2014
Hofmann, M.Gartner, A., Linnemann, U., Hofmann, M.The provenance of northern Kalahari Basin sediments and growth history of the southern Congo Craton reconstructed by U-Pb ages of zircons from recent river sands.International Journal of Earth Sciences, Vol. 103, 2, pp. 579-595.Africa, Southern AfricaGeochronology
DS201412-0367
2014
Hofmann, M.Hofmann, M., Linnemann, U., Hoffmann, K-H., Gerdes, A., Eckelmann, K., Gartner, A.The Namuskluft and Dreigratberg sections in southern Namibia ( Kalahari Craton, Gariep Belt): a geological history of Neoproterozoic rifting and recycling of cratonic crust during the dispersal of Rodinia until the amalgamation of Gondwana.International Journal of Earth Sciences, Vol. 103, pp. 1187-1202.Africa, NamibiaGeochronology
DS202009-1630
2020
Hofmann, M.Hegner, E., Rajesh, S., Willbold, M., Muller, D., Joachimiski, M., Hofmann, M., Linnemann, U., Zieger, J., Pradeepkumar, A.P.Sediment derived origin of the putatative Munnar carbonatite, South India.Journal of Asian Earth Science, Vol. 200, 104432, 18p. PdfIndiadeposit - Munnar

Abstract: Metacarbonate assemblages in high-grade metamorphic terranes often pose challenges when trying to distinguish between mantle-derived carbonatite and sedimentary carbonate protoliths. We present a study of granulite-facies metacarbonate samples of the putative Munnar carbonatite described as decimeter-thick dikes and veins, and layers of a meter-thick metacarbonate and calc-silicate assemblage, respectively. Thin sections of the metacarbonate dike samples show absence of pyrochlore and ubiquitous scapolite, titanite, wollastonite, and detrital zircons are compatible with impure limestone protoliths. Nd and Sr isotope compositions indicate protoliths with Paleoproterozoic crustal residence times which contrast the mantle sources of Indian and global carbonatites. Trace-element patterns display the characteristics of upper crust, and Ce- and Y-anomalies in a number of samples suggest protolith formation under marine conditions. Carbon and oxygen isotope compositions of the metacarbonate samples interlayered with calc-silicate rocks are similar to those in marine limestone. The metacarbonate dikes, however, show mantle-like compositions which are interpreted as reflecting equilibration with mantle-derived CO2 during granulite-facies metamorphism. The dikes yielded a U-Pb zircon crystallization age of 1020 ± 70 Ma and a cross-cutting quartz syenite, thought to be cogenetic, a magmatic age of 620 ± 35 Ma; the hosting gneiss provided a magmatic age of 2452 ± 14 Ma. We conclude that the layered metacarbonate and calc-silicate rocks represent a former marine limestone and marl sequence and the metacarbonate dikes and veins small-volume melts of crust-derived carbonate-rich sediment.
DS1994-0781
1994
Hofmann-Wellenhof, B.Hofmann-Wellenhof, B.Global positioning system theory and practice second editionSpringer, 348pGlobalBook -table of contents, GPS -Global positioning system
DS1993-0683
1993
Hofmann-Wellenhoft, B.Hofmann-Wellenhoft, B., et al.Global positioning systemsSpringer Verlag, 326p. approx. $ 60.00GlobalBook -ad, Global positioning systems
DS200812-0786
2008
HofmeisterNasdala, L., Gigler, Wildner, Grambole, Zaitsev, Harris, Hofmeister, Milledge, SatitkuneAlpha radiation damage in diamond.Goldschmidt Conference 2008, Abstract p.A672.TechnologyDiamond morphology
DS1987-0823
1987
Hofmeister, A.Yoder, H.S. Jr., Boctor, N.Z., Hofmeister, A.Barium and titanium micas from olivine melilitite: a potential new endmember micaEos, abstractSouth AfricaSaltpetre Kop
DS1989-0651
1989
Hofmeister, A.M.Hofmeister, A.M.Vibrational spectra of end member garnetsEos, Vol. 70, No. 15, April 11, p. 351. (abstract.)GlobalMineralogy, Pyrope
DS1991-0723
1991
Hofmeister, A.M.Hofmeister, A.M.Vibrational spectroscopy of minerals at pressure: application to themantleGsa Today, Vol. 1, No. 6, June pp. 117, 118, 119, 122GlobalMantle, Diamonds
DS1996-0640
1996
Hofmeister, A.M.Hofmeister, A.M., et al.Single crystal IR spectroscopy of pyrope almandine garnets with minor amounts of Mn and Ca.American Mineralogist, Vol. 81, pp. 418-28.GlobalMineralogy - garnet
DS200412-0662
2004
Hofmeister, A.M.Giesting, P.A., Hofmeister, A.M., Wopenka, B., Gwanmesia, G.D., Joliff, B.L.Thermal conductivity and thermodynamics of majoritic garnets: implications for the transition zone.Earth and Planetary Science Letters, Vol. 218, 1-2, Jan. 30, pp. 45-56.MantleGeothermometry, heat capacity, entropy
DS200412-0842
2004
Hofmeister, A.M.Hofmeister, A.M.Enhancement of radiative transfer in the upper mantle by OH - in minerals.Physics of the Earth and Planetary Interiors, Vol. 146, 3-4, pp. 483-495.MantleMineralogy
DS200512-0440
2005
Hofmeister, A.M.Hofmeister, A.M., Criss, R.E.Heatflow and mantle convection in the triaxial Earth.Plates, Plumes, and Paradigms, pp. 289-302. ( total book 861p. $ 144.00)MantleConvection
DS200612-0594
2005
Hofmeister, A.M.Hofmeister, A.M.Dependence of diffusive radiative transfer on grain size, temperature, and Fe content: implication for mantle processes.Journal of Geodynamics, Vol. 40, 1, pp. 51-72.MantlePetrology
DS200612-0595
2006
Hofmeister, A.M.Hofmeister, A.M.Is low spin Fe+ present in Earth's mantle?Earth and Planetary Science Letters, Vol. 243, 1-2, pp. 44-52.MantleThermodynamics
DS200712-0447
2007
Hofmeister, A.M.Hofmeister, A.M., Yeun, D.A.Critical phenomena in thermal conductivity: implications for lower mantle dynamics.Journal of Geodynamics, Vol. 44, 3-5, pp. 186-199.MantleGeothermometry
DS201112-0714
2010
Hofmeister, A.M.Nabelek, P.I., Whittington, A.G., Hofmeister, A.M.Strain heating as a mechanism for partial melting and ultrahigh temperature metamorphism in convergent orogens: implications of temperature dependent thermalJournal of Geophysical Research, Vol. 115, B 12 B12417MantleMelting, geodynamics, rheology, geothermometry
DS201312-0396
2013
Hofmeister, A.M.Hofmeister, A.M., Criss, R.E.How irreversible heat transport processes drive Earth's interdependent thermal, structural and chemical evolution.Gondwana Research, Vol. 24, 2, pp. 490-500.MantleGeothermometry
DS200412-1406
2003
Hofmeister, W.Nasdala, L., Brenker, F.E., Glinnemann, J., Hofmeister, W., Gasparik, T., Harris, J.W., Stachel, T., Reese, I.Spectroscopic 2D tomography: residual pressure and strain around mineral inclusions in diamonds.European Journal of Mineralogy, Vol.15, 6, pp. 931-36.TechnologyTechnology - tomography inclusions
DS200512-0768
2005
Hofmeister, W.Nasdala, L., Hofmeister, W., Harris, J.W., Glinnemann, J.Growth zoning and strain patterns inside diamond crystals as revealed by Raman maps.American Mineralogist, Vol. 90, pp. 745-748.Canada, Northwest TerritoriesRaman mapping technology - Panda, Ekati
DS201012-0664
2010
Hofmeister, W.Satikune, S., Zubko, M., Hager, T., Kusz, J., Hofmeister, W.Mineral chemistry and structural relationships of inclusions in diamond crystals. Koffiefontein and FinschInternational Mineralogical Association meeting August Budapest, abstract p. 25.Africa, South AfricaDiamond inclusions
DS201312-0637
2013
Hofmeister, W.Nasdala, L., Grambole, D., Wildner, M., Gigler, A.M., Hainschwang, T., Zaitsev, A.M., Harris, J.W., Milledge, J., Schulze, D.J., Hofmeister, W., Balmer, W.A.Radio-colouration of diamond: a spectroscopic study.Contributions to Mineralogy and Petrology, Vol. 165, pp. 843-861.Africa, South Africa, Democratic Republic of Congo, South America, Brazil, VenezuelaDiamond - colour
DS200812-1189
2008
Hoford, S.P.Turner, J.P., Green, P.F., Hoford, S.P., Lawrence, S.R.Thermal history of the Rio Muni (West Africa) - NE Brazil margins during continental breakup.Earth and Planetary Science Letters, Vol. 270, 3-4, pp. 354-367.Africa, West Africa, South America, BrazilGeothermometry
DS1860-0265
1876
Hofstedr, H.J.Hofstedr, H.J.Geschiedenis Van den Oranje VrystaatS'gravenhage., 251P.Africa, South AfricaDiamond morphology
DS1991-0724
1991
Hofstetter, J.M.Hofstetter, J.M.Environmental law: more worries for directors?Institute of Mining and Metallurgy (IMM) Minerals Industry International, September pp. 5-7GlobalEconomics, Law-environmental
DS2002-0102
2002
HoganBarklage, M.E., Atekwana, Hogan, Kampunzu, ModisiInfluence of preexisting structures on the development of an embryonic rift: evidence from the Okavanago Rift16th. International Conference On Basement Tectonics '02, Abstracts, 1p., 1p.Botswana, northwestRift basins
DS1993-0684
1993
Hogan, J.P.Hogan, J.P.Monomineralic glomerocrysts: textural evidence for mineral resorption during crystallization of igneous rocksJournal of Geology, Vol. 101, No. 3, July, pp. 531-540GlobalIgneous rocks, Crystal fractionation
DS1997-1052
1997
Hogan, J.P.Sinha, A.K., Whalen, J.B., Hogan, J.P.The nature of magmatism in the Appalachian OrogenGeological Society of America, MWR 191, 438p. approx. $ 110.00 United StatesAppalachiaBook - ad, Orogeny, magmatism
DS1998-0630
1998
Hogan, J.P.Hogan, J.P., Price, J.D., Gilbert, M.C.Magma traps and driving pressure: consequences for pluton shape and emplacement in an extensional regime.Journal of Structural Geology, Vol. 20, No. 9/10, Sept. pp. 1155-68.GlobalTectonics, structure, Not specific to diamonds
DS2002-1009
2002
Hogan, J.P.Mataragio, J.P., Ohde, S., Hogan, J.P.Geochemistry of PAnd a Hill carbonatites from Tanzania: implications for their origin and evolution.16th. International Conference On Basement Tectonics '02, Abstracts, 2p., 2p.TanzaniaGeochronology
DS1960-0682
1966
Hogarth, D.D.Hogarth, D.D.Intrusive Carbonate Rock Near Ottawa, CanadaFourth International Min. Association Meeting Publishing Min. Soc. of India., PP. 46-47.Canada, OntarioBlank
DS1984-0358
1984
Hogarth, D.D.Hogarth, D.D.Fenites and Carbonatites of the National Capital RegionGeological Association of Canada (GAC), Vol. 9, P. 74. (abstract.).Canada, Ontario, QuebecRelated Rocks
DS1984-0359
1984
Hogarth, D.D.Hogarth, D.D., Lapointe, P.Amphibole and Pyroxene Development in Fenite from Cantley, Quebec.Canadian Mineralogist., Vol. 22, PP. 281-295.Canada, QuebecRelated Rocks, Carbonatite
DS1985-0293
1985
Hogarth, D.D.Hogarth, D.D., Hartree, R., Loop, J., Solberg, T.N.Rare Earth Element Minerals in Four Carbonatites Near Gatineau QuebecAmerican Mineralogist, Vol. 70, pp. 1135-1142QuebecCarbonatite, Rare Earths
DS1986-0367
1986
Hogarth, D.D.Hogarth, D.D.Mineralogy of carbonatites: a reviewGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 82. (abstract.)GlobalCarbonatite
DS1986-0368
1986
Hogarth, D.D.Hogarth, D.D., Rushforth, P.Carbonatites and fenites near Ottawa, Ontario and Gatineau QuebecGeological Association of Canada (GAC) Field trip Guidebook, No. 9B, 19pQuebecBlackburn, McCloskey, Haycock, Templeton, Quinnville, Perk, Carbonatite
DS1987-0296
1987
Hogarth, D.D.Hogarth, D.D., Chao, G.Y., Townsend, M.G.Potassium and fluorine rich amphiboles from the Gatineau area, QuebecCanadian Mineralogist, Vol. 25, pt. 4, December pp. 739-753QuebecCarbonatite
DS1988-0122
1988
Hogarth, D.D.Charbonneau, B.W., Hogarth, D.D.Geophysical expression of the carbonatites and fenites, east of Cantley, QuebecGeological Survey of Canada Current Research Part C., pp. 259-270QuebecCarbonatite
DS1989-0652
1989
Hogarth, D.D.Hogarth, D.D.Pyrochlore, apatite and amphibole: distinctive minerals in carbonatiteCarbonatites -Genesis and Evolution, Ed. K. Bell Unwin Hyman Publ, pp. 105-148GlobalCarbonatite, Listing, Detailed mineral
DS1989-0653
1989
Hogarth, D.D.Hogarth, D.D., Roddick, J.C.Discovery of Martin Frobisher's Baffin Island "ore" in IrelandCanadian Journal of Earth Sciences, Vol. 26, pp. 1053-60.IrelandHistory - samples, Ultramafic rocks
DS1990-0710
1990
Hogarth, D.D.Hogarth, D.D., Katsube, T.J.Migration of elements from carbonatites into dolostone at Carillon Dam, southeastern OntarioGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Vancouver 90 Program with Abstracts, Held May 16-18, Vol. 15, p. A59. AbstractOntarioCarbonatite
DS1995-0811
1995
Hogarth, D.D.Hogarth, D.D., Peterson, T.D.Leucite bearing dykes of southeast Baffin Island: a new lamproite locality.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol.Northwest Territories, Baffin IslandLamproite
DS1995-0812
1995
Hogarth, D.D.Hogarth, D.D., Peterson, T.D.Leucite bearing dykes of southeast Baffin Island: a new lamproite localityGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Annual Meeting Abstracts, Vol. 20, p. A45 AbstractNorthwest Territories, Baffin IslandLamproites
DS1995-0813
1995
Hogarth, D.D.Hogarth, D.D., Williams, C.T.Zoned crystals of pyrochlore - group minerals from carbonatiteGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Annual Meeting Abstracts, Vol. 20, p. A45 AbstractGlobalMineralogy, Carbonatite
DS1996-0641
1996
Hogarth, D.D.Hogarth, D.D., Peterson, T.D.Lamproite dykes of southeast Baffin IslandGeological Survey of Canada, LeCheminant ed, OF 3228, pp. 109-100.Northwest Territories, Baffin IslandLamproite, Dykes
DS1997-0512
1997
Hogarth, D.D.Hogarth, D.D.Mineralogy of leucite bearing dykes from Napoleon Bay, Baffin Island:multistage Proterozoic lamproites.Canadian Mineralogist, Vol. 35, No. 1, Feb. pp. 53-78.GlobalLamproites, Dykes - mineralogy
DS1997-0513
1997
Hogarth, D.D.Hogarth, D.D.Carbonatites, fenites and associated phenomena near OttawaGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Guidebook, No. A4, 21p.Ontario, QuebecCarbonatite, Guidebook
DS2000-0414
2000
Hogarth, D.D.Hogarth, D.D., Williams, C.T., Jones, P.Primary zoning in pyrochlore group minerals from carbonatitesMineralogical Magazine, Vol. 64, No. 4, Aug. 1, pp.675-83.GlobalCarbonatite
DS201707-1335
2016
Hogarth, D.D.Hogarth, D.D.Chemical trends in the Meech Lake Quebec, carbonatites and fenites.The Canadian Mineralogist, Vol 54, pp. 1105-1128.Canada, Quebeccarbonatite - Meech Lake

Abstract: Near Meech Lake, Québec, the edges of Mesoproterozoic carbonatite dikes are composed of calcite, dolomite, fluorapatite, phlogopite, amphibole, and pyrochlore. The carbonatite is separated from amphibole-fenite by a narrow, fine-grained reaction selvage of phlogopite pierced with long prisms of amphibole. The amphibole is mainly richterite, but it extends to magnesio-arfvedsonite (overgrowth, crystal rim). Uranium-rich pyrochlore is metamict and ranges from calciopyrochlore to kenopyrochlore with Ta-U enrichment in crystal rims. Chemical characteristics of the suite are: (1) F and Nb highest in the selvage, and (2) decline of Sr and Ce outwards from the carbonatite. A similar pattern (this research) is found at Fen, Norway. Rare earths are enriched in LREE with smooth downward-sloping patterns, in chondrite-normalized curves, to HREE. Two major surges of mineralization are suggested: (1) early, metasomatic-alkalic, creating fenites with enrichment in Mg, Na, and K; and (2) later igneous depositing carbonatites and introducing first F, P, and Nb, then Ca, Sr, and Ce. Thermochemical and geochronological data place carbonate equilibration at 700 °C and the emplacement at 1026 Ma b.p. Calciocarbonatites, in monzonitic orthogneiss, are enriched in Ba and Ce. They are composed of baryte, calcite, phlogopite, fluorapatite, magnesio-riebeckite, and non-metamict allanite-(Ce). A mica selvage is present, but amphibole fenite is almost completely lacking. Magnesiocarbonatite has a well-developed selvage against granite but lacks significant amphibole fenite. In breccia cement at nearby Fortune Lake, pyrochlore is associated with abundant fluorapatite but lacks carbonates. The Cambro-Proterozoic calciocarbonatite near Fen, Norway is particularly Nb-rich in breccia zones, and pyroxene fenite takes the place of amphibole fenite at Meech Lake. In contrast to a relatively anorogenic regime during carbonatite petrogenesis at Fen, metamorphism has obscured pyrochlore zonation and enhanced amphibole growth at Meech Lake
DS201609-1721
2016
Hogberg, K.Hogberg, K., Stachel, T., Stern, R.A.Carbon and nitrogen isotope systematics in diamond: different sensitivities to isotopic fractionation or a decoupled origin?Lithos, In press available 15p.Canada, Nunavut, Baffin IslandDeposit - Chidliak

Abstract: Using stable isotope data obtained on multiple aliquots of diamonds from worldwide sources, it has been argued that carbon and nitrogen in diamond are decoupled. Here we re-investigate the carbon-nitrogen relationship based on the most comprehensive microbeam data set to date of stable isotopes and nitrogen concentrations in diamonds (n = 94) from a single locality. Our diamond samples, derived from two kimberlites in the Chidliak Field (NE Canada), show large variability in d13C (- 28.4 ‰ to - 1.1‰, mode at - 5.8‰), d15N (- 5.8 to + 18.8‰, mode at - 3.0‰) and nitrogen contents ([N]; 3800 to less than 1 at.ppm). In combination, cathodoluminescence imaging and microbeam analyses reveal that the diamonds grew from multiple fluid pulses, with at least one major hiatus documented in some samples that was associated with a resorption event and an abrupt change from low d13C and [N] to mantle-like d13C and high [N]. Overall, d13C appears to be uncorrelated to d15N and [N] on both the inter- and intra-diamond levels. Co-variations of d15N-log[N], however, result in at least two parallel, negatively correlated linear arrays, which are also present on the level of the individual diamonds falling on these two trends. These arrays emerge from the two principal data clusters, are characterized by slightly negative and slightly positive d15N (about - 3 and + 2‰, respectively) and variable but overall high [N]. Using published values for the diamond-fluid nitrogen isotope fractionation factor and nitrogen partition coefficient, these trends are perfectly reproduced by a Rayleigh fractionation model. Overall, three key elements are identified in the formation of the diamond suite studied: (1.) a low d13C and low [N] component that possibly is directly associated with an eclogitic diamond substrate or introduced during an early stage fluid event. (2.) Repeated influx of a variably nitrogen-rich mantle fluid (mildly negative d13C and d15N). (3.) In waning stages of influx, availability of the mantle-type fluid at the site of diamond growth became limited, leading to Rayleigh fractionation. These fractionation trends are clearly depicted by d15N-[N] but are not detected when examining co-variation diagrams involving d13C. Also on the level of individual diamonds, large (= 5‰) variations in d15N are associated with d13C values that typically are constant within analytical uncertainty. The much smaller isotope fractionation factor for carbon (considering carbonate- or methane-rich fluids as possible carbon sources) compared to nitrogen leads to an approximately one order of magnitude lower sensitivity of d13C values to Rayleigh fractionation processes (i.e. during fractionation, a 1‰ change in d13C is associated with a 10‰ change in d15N). As a consequence, even minor heterogeneity in the primary isotopic composition of diamond forming carbon (e.g., due to addition of minor subducted carbon) will completely blur any possible co-variations with d15N or [N]. We suggest this strong difference in isotope effects for C and N to be the likely cause of observations of an apparently decoupled behaviour of carbon and nitrogen isotopes in diamond.
DS201610-1871
2016
Hogberg, K.Hogberg, K.,Stachel, T., Stern, R.A.Carbon and nitrogen isotope systematics in diamond: different sensitivities to isotopic fractionation or a decoupled origin?Lithos, in press available 15p.Canada, NunavutDeposit - Chidliak

Abstract: Using stable isotope data obtained on multiple aliquots of diamonds from worldwide sources, it has been argued that carbon and nitrogen in diamond are decoupled. Here we re-investigate the carbon-nitrogen relationship based on the most comprehensive microbeam data set to date of stable isotopes and nitrogen concentrations in diamonds (n = 94) from a single locality. Our diamond samples, derived from two kimberlites in the Chidliak Field (NE Canada), show large variability in d13C (- 28.4 ‰ to - 1.1‰, mode at - 5.8‰), d15N (- 5.8 to + 18.8‰, mode at - 3.0‰) and nitrogen contents ([N]; 3800 to less than 1 at.ppm). In combination, cathodoluminescence imaging and microbeam analyses reveal that the diamonds grew from multiple fluid pulses, with at least one major hiatus documented in some samples that was associated with a resorption event and an abrupt change from low d13C and [N] to mantle-like d13C and high [N]. Overall, d13C appears to be uncorrelated to d15N and [N] on both the inter- and intra-diamond levels. Co-variations of d15N-log[N], however, result in at least two parallel, negatively correlated linear arrays, which are also present on the level of the individual diamonds falling on these two trends. These arrays emerge from the two principal data clusters, are characterized by slightly negative and slightly positive d15N (about - 3 and + 2‰, respectively) and variable but overall high [N]. Using published values for the diamond-fluid nitrogen isotope fractionation factor and nitrogen partition coefficient, these trends are perfectly reproduced by a Rayleigh fractionation model. Overall, three key elements are identified in the formation of the diamond suite studied: (1.) a low d13C and low [N] component that possibly is directly associated with an eclogitic diamond substrate or introduced during an early stage fluid event. (2.) Repeated influx of a variably nitrogen-rich mantle fluid (mildly negative d13C and d15N). (3.) In waning stages of influx, availability of the mantle-type fluid at the site of diamond growth became limited, leading to Rayleigh fractionation. These fractionation trends are clearly depicted by d15N-[N] but are not detected when examining co-variation diagrams involving d13C. Also on the level of individual diamonds, large (= 5‰) variations in d15N are associated with d13C values that typically are constant within analytical uncertainty. The much smaller isotope fractionation factor for carbon (considering carbonate- or methane-rich fluids as possible carbon sources) compared to nitrogen leads to an approximately one order of magnitude lower sensitivity of d13C values to Rayleigh fractionation processes (i.e. during fractionation, a 1‰ change in d13C is associated with a 10‰ change in d15N). As a consequence, even minor heterogeneity in the primary isotopic composition of diamond forming carbon (e.g., due to addition of minor subducted carbon) will completely blur any possible co-variations with d15N or [N]. We suggest this strong difference in isotope effects for C and N to be the likely cause of observations of an apparently decoupled behaviour of carbon and nitrogen isotopes in diamond.
DS1860-0753
1892
Hogbom, A.G.Hogbom, A.G.Syeniteomradet Pa AlnonGeol. Foren. Forhandl., Vol. 14, PP. 15-19.Europe, Norway, ScandinaviaAlnoite
DS1860-0891
1895
Hogbom, A.G.Hogbom, A.G.Ueber das Nephelinsyenit Gebiet auf der Insel AlnoGeol. Foren. Forhandl., Vol. 17, PP. 100-160; PP. 214-256.Europe, Sweden, ScandinaviaAlnoite
DS1900-0764
1909
Hogbom, A.G.Hogbom, A.G.The Igneous Rocks of Ragunda, Alno, Rodo, NordingraGeol. Foren. Forhandl., Vol. 31, PP. 356-364.Europe, Norway, ScandinaviaUltramafic And Related Rocks
DS1910-0059
1910
Hogbom, A.G.Hogbom, A.G.Precambrian Geology of SwedenGeol. Institute Uppsala Bulletin., Vol. 10, PP. 1-80.Sweden, ScandinaviaUltramafic And Related Rocks
DS2003-0112
2003
Hogdahl, K.Bingen, B., Nordgulen, O., Sigmond, E.M., Tucker, R., Mansfeld, J., Hogdahl, K.Relations between 1.19 - 1.13 Ga continental magmatism, sedimentation andPrecambrian Research, Vol. 124, 2-4, pp. 215-241.NorwayBlank
DS200412-0155
2003
Hogdahl, K.Bingen, B., Nordgulen, O., Sigmond, E.M., Tucker, R., Mansfeld, J., Hogdahl, K.Relations between 1.19 - 1.13 Ga continental magmatism, sedimentation and metamorphism, Sveconorwegian province, S. Norway.Precambrian Research, Vol. 124, 2-4, pp. 215-241.Europe, NorwayMagmatism
DS201907-1561
2019
Hogdahl, K.Mattsson, H.B., Hogdahl, K., Carlsson, M., Malehmir, A.The role of mafic dykes in the petrogenesis of the Archean Siilinjarvi carbonatite complex, east central Finland.Lithos, in press available, 37p.Europe, Finlandcarbonatites

Abstract: The Archean (~2.6?Ga) Siilinjärvi carbonatite complex in east-central Finland is crosscut by a few ultramafic lamprophyre dykes, together with a broad array of more evolved mafic dykes that range in composition from foidites to various types of alkali basalts. A possible genetic link between the primitive lamprophyres and the carbonatite complex has previously been hypothesised, but their exact relations have been unclear due to the regional metamorphic overprint (i.e., greenschist facies). Here we focus on the petrology and petrography of the mafic dykes, and integrate the data to present a coherent model that can explain the genesis of the Siilinjärvi carbonatite complex. Field-relations, in combination with petrography and geochemistry, indicate that there are at least three generations of mafic dykes present. The oldest dykes (Generation I) are strongly deformed, and inferred to have been emplaced shortly after the formation of the complex itself. These dykes can be divided into two groups (i.e., ultramafic lamprophyres and Group A), where Group A comprises foidites characterised by low SiO2 (41.4-51.5?wt%) and high alkali (>10?wt% K2O) content. We interpret the foiditic magmas to have evolved from primitive ultramafic lamprophyres by fractionating a clinopyroxene-olivine dominated mineral assemblage that was devoid of feldspar. This fractionation path forced alkali-enrichment in the magmas belonging to Group A, which pushed them into the miscibility gap, and resulted in liquid immiscibility that produced moderately alkaline conjugate carbonatite(s). Subsequent fractionation of the conjugate carbonatite by predominantly calcite and apatite produced the mineralogically homogeneous carbonatite cumulate that is exposed at Siilinjärvi. Younger, less deformed, mafic dykes (belonging to Generations II and III) exhibit trace element characteristics, broadly similar to basaltic dyke swarms in the region. The younger dykes are characterised by the presence of large plagioclase crystals in thin sections. Crystallisation of a feldspar-bearing mineral assemblage resulted in only moderate enrichment of alkalis with increased fractionation, which caused the younger dykes to evolve along the more common basalt-to-trachyte series. Thus, the magmas belonging to Generations II and III at Siilinjärvi never fulfilled the conditions required to produce carbonatites by liquid immiscibility.
DS1950-0329
1957
Hogeboom, W.L.Hogeboom, W.L.The Petrology of Green Street Peridotite Dikes in Syracuse New York.Msc. Thesis, Syracuse University., 95P.United States, Appalachia, New YorkPetrology, Kimberlite, Mineralogy
DS1994-1293
1994
Hogelsberger, H.O'Connor, P.J., Hogelsberger, H., Feely, M., Rex, D.C.Fluid inclusion studies, rare-earth element chemistry and age of hydrothermal fluid mineralization in w Ireland- link continental rifting?Institute of Mining and Metallurgy (IMM) Bulletins, Vol. 102, pp. B141-B148IrelandGeochemistry, Geochronology
DS201012-0170
2010
Hogg, A.J.Doyle, E.E., Hogg, A.J., Mader, H.M., Sparks, R.S.J.A two layer model for the evolution and propogation of dense and dilute regions of pyroclastic currents.Journal of Volcanology and Geothermal Research, Vol. 190, 3-4, pp. 365-378.TechnologyVolcanism
DS1989-0294
1989
Hogg, D.C.Corr, D.G., Tailor, A.M., Cross, A., Hogg, D.C., Lawrence, D.H.Progress in automatic analysis of multi-temporal remotely sensed dataInternational Journal of Remote Sensing, Vol. 10, No. 6, June pp. 1175-1196GlobalRemote sensing, Computer Program
DS1970-0536
1972
Hogg, J.M.Hogg, J.M.E.l. 516, Gundagai New South Wales. First and Final Report Stockdale Prospecting Ltd.New South Wales Geological Survey, GS 1972/386, (UNPUBL.).Australia, New South WalesKimberlite, Diamond, Gundagir Area, Nepheline Basanite, Alnoite
DS1970-0719
1973
Hogg, J.M.Hogg, J.M.E.l. 567, Jugiong. First and Final Report Stockdale Prospecting Ltd.New South Wales Geological Survey, GS 1973/184, (UNPUBL.).AustraliaKimberlite, Diamond, Jugiong Area
DS1950-0106
1952
Hogg, N.Hogg, N., Satterly, J., Wilson, A.E.Drilling in the James Bay Lowland: Part 1, Drilling by the Ontario Government.Ontario Department of Mines Annual Report, Vol. 61, PT. 6, PP. 115-140.Canada, OntarioProspecting, Kimberlite
DS2000-0415
2000
Hogg, S.Hogg, S.A review of the geophysical discovery of kimberlites in and beneath the Paleozoic cover, with a look ahead...Toronto Geological Discussion Group, absts Oct. 24, pp. 16-20.OntarioGeophysics, Diamond exploration
DS2000-0416
2000
Hogg, S.Hogg, S., Munro, S.The aeromagnetic discovery of kimberlites and sulphides at depthSociety of Exploration Geophysics Conference, Aug. 4p.Ontario, James Bay LowlandsGeophysics
DS201706-1081
2017
Hogg, S.Hogg, S., Munro, S.The geophysical history of discoveries in the James Bay Lowlands from the Victor kimberlite to the Ring of Fire copper and nickel deposits.exploration17.com, 1p. AbstractCanada, Ontariogeophysics

Abstract: The James Bay Lowlands is a large remote area of Northern Ontario with very limited access. The Archean basement rocks lie beneath a layer of Paleozoic limestone, up to 300 m thick, that is topped by glacial till and bog. This setting, without outcrop or hard geological knowledge, presented a blank slate well suited to airborne geophysical exploration. This paper presents the aeromagnetic survey methodology and analysis techniques that evolved from the initial kimberlite aeromagnetic program carried out by Selco in 1979 through the 1989 DeBeers discovery of the Victor kimberlite and the 1993 Spider/KWG discovery of the older sub-Paleozoic Kyle series kimberlites and eventually the Ring of Fire. Without property constraints the exploration methodology was a cycle of survey-interpret-drill then move on and repeat as discoveries and finances permitted. After 3 cycles of kimberlite discovery a Spider/KWG/DeBeers partnership encountered VMS copper mineralization in 2001. An airborne EM survey in 2003 identified a number of excellent prospects and the most technically promising became the Noront Eagles Nest MMS nickel deposit that began the Ring of Fire saga. These greenfield discoveries, in a blind geological environment beneath limestone cover, illustrate the potential effectiveness of geophysically directed exploration.
DS201607-1302
2016
Hoggard, M.J.Hoggard, M.J., White, N., Al-Attar, D.Global dynamic topography observations reveal limited influences of large scale mantle flow.Nature Geoscience, Vol. 9, 6, pp. 456-463.MantleGeodynamics

Abstract: Convective circulation of the Earth’s mantle maintains some fraction of surface topography that varies with space and time. Most predictive models show that this dynamic topography has peak amplitudes of about ±2?km, dominated by wavelengths of 104?km. Here, we test these models against our comprehensive observational database of 2,120 spot measurements of dynamic topography that were determined by analysing oceanic seismic surveys. These accurate measurements have typical peak amplitudes of ±1?km and wavelengths of approximately 103?km, and are combined with limited continental constraints to generate a global spherical harmonic model, the robustness of which has been carefully tested and benchmarked. Our power spectral analysis reveals significant discrepancies between observed and predicted dynamic topography. At longer wavelengths (such as 104?km), observed dynamic topography has peak amplitudes of about ±500?m. At shorter wavelengths (such as 103?km), significant dynamic topography is still observed. We show that these discrepancies can be explained if short-wavelength dynamic topography is generated by temperature-driven density anomalies within a sub-plate asthenospheric channel. Stratigraphic observations from adjacent continental margins show that these dynamic topographic signals evolve quickly with time. More rapid temporal and spatial changes in vertical displacement of the Earth’s surface have direct consequences for fields as diverse as mantle flow, oceanic circulation and long-term climate change.
DS201810-2373
2018
Hoggard, M.J.Roberts, G.G., White, N., Hoggard, M.J., Ball, P.W., Meenan, C.A Neogene history of mantle convective support beneath Borneo.Earth and Planetary Science Letters, Vol. 496, 1, pp. 142-158.Asia, Borneoconvection

Abstract: Most, but not all, geodynamic models predict 1-2 km of mantle convective draw-down of the Earth's surface in a region centered on Borneo within southeast Asia. Nevertheless, there is geomorphic, geologic and geophysical evidence which suggests that convective uplift might have played some role in sculpting Bornean physiography. For example, a long wavelength free-air gravity anomaly of +60 mGal centered on Borneo coincides with the distribution of Neogene basaltic magmatism and with the locus of sub-plate slow shear wave velocity anomalies. Global positioning system measurements, an estimate of elastic thickness, and crustal isostatic considerations suggest that regional shortening does not entirely account for kilometer-scale regional elevation. Here, we explore the possible evolution of the Bornean landscape by extracting and modeling an inventory of 90 longitudinal river profiles. Misfit between observed and calculated river profiles is minimized by smoothly varying uplift rate as a function of space and time. Erosional parameters are chosen by assuming that regional uplift post-dates Eocene deposition of marine carbonate rocks. The robustness of this calibration is tested against independent geologic observations such as thermochronometric measurements, offshore sedimentary flux calculations, and the history of volcanism. A calculated cumulative uplift history suggests that kilometer-scale Bornean topography grew rapidly during Neogene times. This suggestion is corroborated by an offshore Miocene transition from carbonate to clastic deposition. Co-location of regional uplift and slow shear wave velocity anomalies immediately beneath the lithospheric plate implies that regional uplift could have been at least partly generated and maintained by temperature anomalies within an asthenospheric channel.
DS201911-2517
2019
Hoggard, M.J.Davies, D.R., Valentine, A.P., Kramer, S.C., Rawlinson, N., Hoggard, M.J., Eakin, C.M., Wilson, C.R.Earth's multi-scale topographic response to global mantle flow.Nature Geosciences, Vol. 12, pp. 845-850.Mantlegeodynamics

Abstract: Earth’s surface topography is a direct physical expression of our planet’s dynamics. Most is isostatic, controlled by thickness and density variations within the crust and lithosphere, but a substantial proportion arises from forces exerted by underlying mantle convection. This dynamic topography directly connects the evolution of surface environments to Earth’s deep interior, but predictions from mantle flow simulations are often inconsistent with inferences from the geological record, with little consensus about its spatial pattern, wavelength and amplitude. Here, we demonstrate that previous comparisons between predictive models and observational constraints have been biased by subjective choices. Using measurements of residual topography beneath the oceans, and a hierarchical Bayesian approach to performing spherical harmonic analyses, we generate a robust estimate of Earth’s oceanic residual topography power spectrum. This indicates water-loaded power of 0.5?±?0.35?km2 and peak amplitudes of up to ~0.8?±?0.1?km at long wavelengths (~104?km), decreasing by roughly one order of magnitude at shorter wavelengths (~103?km). We show that geodynamical simulations can be reconciled with observational constraints only if they incorporate lithospheric structure and its impact on mantle flow. This demonstrates that both deep (long-wavelength) and shallow (shorter-wavelength) processes are crucial, and implies that dynamic topography is intimately connected to the structure and evolution of Earth’s lithosphere.
DS202007-1147
2020
Hoggard, M.J.Hoggard, M.J., Parnell-Turner, R., White, N. Hotspots and mantle plumes revisited: towards reconciling the mantle heat transfer discrepancy.Earth and Planetary Science Letters, Vol. 542, 116317 16p. PdfMantleplumes, geothermometry

Abstract: Mantle convection is the principal mechanism by which heat is transferred from the deep Earth to the surface. Cold subducting slabs sink into the mantle and steadily warm, whilst upwelling plumes carry heat to the base of lithospheric plates where it can subsequently escape by conduction. Accurate estimation of the total heat carried by these plumes is important for understanding geodynamic processes and Earth's thermal budget. Existing estimates, based upon swell geometries and velocities of overriding plates, yield a global heat flux of ~2 TW and indicate that plumes play only a minor role in heat transfer. Here, we revisit the Icelandic and Hawaiian plumes to show that their individual flux estimates are likely to be incorrect due to the assumption that buoyancy is mainly produced within the lithosphere and therefore translates at plate velocities. We develop an alternative methodology that depends upon swell volume, is independent of plate velocities, and allows both for decay of buoyancy through time and for differential motion between asthenospheric buoyancy and the overlying plate. Reanalysis of the Icelandic and Hawaiian swells yields buoyancy fluxes of Mg s-1 and Mg s-1, respectively. Both swells are used to calibrate a buoyancy decay timescale of ~45 Myr for the new volumetric approach, which enables buoyancy fluxes to be estimated for a global inventory of 53 swells. Estimates from magmatic hotspots yield a cumulative lower bound on global plume flux of 2 TW, which increases to 6 TW if amagmatic swells are also included and if all buoyancy is assumed to be thermal in origin. Our results suggest that upwelling plumes play a significant role in the transfer of heat into the uppermost mantle.
DS202008-1400
2020
Hoggard, M.J.Hoggard, M.J., Czarnota, K., Richards, F.D., Huston, D.L., Jaques, A.L., Ghelichkhan, S.Global distribution of sediment hosted metals controlled by craton edge stability. ( not specific to diamonds but of interest)Nature Geoscience, Vol. 13, pp. 504-510.Mantlelithospheric thickness

Abstract: Sustainable development and the transition to a clean-energy economy drives ever-increasing demand for base metals, substantially outstripping the discovery rate of new deposits and necessitating dramatic improvements in exploration success. Rifting of the continents has formed widespread sedimentary basins, some of which contain large quantities of copper, lead and zinc. Despite over a century of research, the geological structure responsible for the spatial distribution of such fertile regions remains enigmatic. Here, we use statistical tests to compare deposit locations with new maps of lithospheric thickness, which outline the base of tectonic plates. We find that 85% of sediment-hosted base metals, including all giant deposits (>10?megatonnes of metal), occur within 200?kilometres of the transition between thick and thin lithosphere. Rifting in this setting produces greater subsidence and lower basal heat flow, enlarging the depth extent of hydrothermal circulation available for forming giant deposits. Given that mineralization ages span the past two?billion?years, this observation implies long-term lithospheric edge stability and a genetic link between deep Earth processes and near-surface hydrothermal mineral systems. This discovery provides an unprecedented global framework for identifying fertile regions for targeted mineral exploration, reducing the search space for new deposits by two-thirds on this lithospheric thickness criterion alone.
DS1994-0782
1994
Hogrefe, A.Hogrefe, A., Rubie, D.C., Sharp, T.G., Seifert, F.Metastability of enstatite in deep subducting lithosphereNature, Vol. 372, Nov. 24, pp. 351-353.MantleSubduction, Petrology -experimental
DS2001-0548
2001
Hoham, R.W.Jones, H.G., Pomeroy, J.W., Walker, D.A., Hoham, R.W.Snow ecology: an inter disciplinary examination of snow-covered ecosystems. BOOK REVIEW Cambridge Univ. Press, 378p. @ 80.00 USGeoscience Canada, Vol.29,2, June pp. 89-90.CanadaBook - review, Snow ecosystem
DS2002-1169
2002
Hohdorf, A.Oberthur, T., Davis, D.W., Blenkinsop, T., Hohdorf, A.Precise U Pb mineral ages, Rb Sr and Sm Nd systematics for the Great Dyke, constraints on late Archean eventsPrecambrian Research, Vol. 113, No. 3-4, pp. 293-305.ZimbabweGeochronology, Craton, uranium, lead, rubidium, strontium, Limpopo Belt
DS2003-0612
2003
Hohenberg, C.M.Huss, G.R., Meshik, A.P., Smith, J.B., Hohenberg, C.M.Presolar diamond, silicon carbide and graphite in carbonaceous chondrites: implicationsGeochimica et Cosmochimica Acta, Vol. 67, 24, pp. 4823-48.GlobalDiamond - meteorites
DS200412-0860
2003
Hohenberg, C.M.Huss, G.R., Meshik, A.P., Smith, J.B., Hohenberg, C.M.Presolar diamond, silicon carbide and graphite in carbonaceous chondrites: implications for thermal processing in the solar nebuGeochimica et Cosmochimica Acta, Vol. 67, 24, pp. 4823-48.TechnologyDiamond - meteorites
DS201603-0379
2015
Hohensee, G.T.Goncharov, A.F., Lobanov, S.S., Tan, X., Hohensee, G.T., Cahill, D.G., Lin, J-F., Thomas, S-M., Okuchi, T., Tomioka, N., Helffrich, G.Experimental study of thermal conductvity at high pressures: implication for the deep Earth's interior.Physics of the Earth and Planetary Interiors, Vol. 247, pp. 11-16.MantleExperimental Petrology

Abstract: Lattice thermal conductivity of ferropericlase and radiative thermal conductivity of iron bearing magnesium silicate perovskite (bridgmanite) - the major mineral of Earth’s lower mantle- have been measured at room temperature up to 30 and 46 GPa, respectively, using time-domain thermoreflectance and optical spectroscopy techniques in diamond anvil cells. The results provide new constraints for the pressure dependencies of the thermal conductivities of Fe bearing minerals. The lattice thermal conductivity of ferropericlase Mg0.9Fe0.1O is 5.7(6) W/(m * K) at ambient conditions, which is almost 10 times smaller than that of pure MgO; however, it increases with pressure much faster (6.1(7)%/GPa vs 3.6(1)%/GPa). The radiative conductivity of a Mg0.94Fe0.06SiO3 bridgmanite single crystal agrees with previously determined values for powder samples at ambient pressure; it is almost pressure-independent in the investigated pressure range. Our results confirm the reduced radiative conductivity scenario for the Earth’s lower mantle, while the assessment of the heat flow through the core-mantle boundary still requires in situ measurements at the relevant pressure-temperature conditions.
DS201112-0534
2011
Hohl, S.Konig, S., Munker, C., Hohl, S., Paulick, H., Barth, A.R., Lagos, M., Pfander, J., Buchl, A.The Earth's tungsten budget during mantle melting and crust formation.Geochimica et Cosmochimica Acta, Vol. 78, 8, pp. 2119-2136.MantleMelting - not specific to diamonds
DS1989-1113
1989
Hohmann, G.W.Newman, G.A., Anderson, W.L., Hohmann, G.W.Effect of conductive host rock on borehole transient electromagneticresponsesGeophysics, Vol. 54, No. 5, May pp. 598-608GlobalGeophysics, electromagnetic -host rock
DS200412-1894
2004
Hohmann, R.Srinivasan, A., Top,Z., Sclosser, P., Hohmann, R., Iskandarani, M., Olson, D.B., Lupton, J.E., Jenkins, W.J.Mantle 3 He distribution and deep circulation in the Indian Ocean.Journal of Geophysical Research, Vol. 109, 6, 10.1029/2003 JC002028Indian OceanMineralogy
DS202004-0544
2020
Hohn, S.Will, T.M., Hohn, S., Frimmel, H.E., Gaucher, C., Le Roux, P.J., Macey, P.H.Petrological, geochemical and isotopic data of Neoproterozoic rock units from Uruguay and South Africa: correlation of basement terranes across the South Atlantic.Gondwana Research, Vol. 80, pp. 12-32.South America, Uruguay, Brazil, Africa, Namibiacraton

Abstract: Felsic to intermediate igneous rocks from the Cuchilla Dionisio (or Punta del Este) Terrane (CDT) in Uruguay and the Várzea do Capivarita Complex (VCC) in southern Brazil were emplaced in the Tonian and experienced high-grade metamorphism towards the end of the Cryogenian. Geological and geochemical data indicate an S-type origin and formation in a continental within-plate setting by recycling of lower crustal material that was initially extracted from the mantle in the Palaeoproterozoic. Similar felsic igneous rocks of Tonian age occur in the Richtersveld Igneous Complex and the Vredefontein and Rosh Pinah formations in westernmost South Africa and southern Namibia and have been correlated with their supposed equivalents in Uruguay and Brazil. Geochemical and isotope data of the largely unmetamorphosed felsic igneous rocks in southwestern Africa imply a within-plate origin and formation by partial melting or fractional crystallization of mafic rocks that were extracted from the mantle in the Proterozoic. The parental melts of all of these Tonian igneous rocks from South America and southwestern Africa formed in an anorogenic continental setting at the western margin of the Kalahari Craton and were emplaced in, and/or contaminated by, Namaqua Province-type basement after separation from their source region. However, the source regions and the time of extractions thereof are different and, moreover, occurred at different palaeogeographical latitudes. New petrological data of CDT high-grade gneiss indicate a geothermal gradient of c. 20-25 °C/km, implying continental collisional tectonics following subduction and ocean basin closure at an active continental margin at the eastern edge of present-day South America in the late Cryogenian to early Ediacaran. The associated suture may be traced by the high-grade gneiss and amphibolite-facies mafic rocks in the CDT and probably continues northwards to the Arroio Grande Complex and the VCC in southern Brazil.
DS202101-0007
2020
Hohn, S.Decree, S., Savolainen, M., Mercadier, J., Debaille, V., Hohn, S., Frimmel, H., Baele, J-M.Geochemical and spectroscopic investigation of apatite in the Siilinjarvi carbonatite complex: keys to understanding apatite forming processes and assessing potential for rare earth elements.Applied Geochemistry, Vol. 123, 104778 17p. PdfEurope, Finlanddeposit - Siilinjarvi

Abstract: The Siilinjärvi phosphate deposit (Finland) is hosted by an Archean carbonatite complex. The main body is composed of glimmerite, carbonatite and combinations thereof. It is surrounded by a well-developed fenitization zone. Almost all the rocks pertaining to the glimmerite-carbonatite series are considered for exploitation of phosphate. New petrological and in-situ geochemical as well as spectroscopic data obtained by cathodoluminescence, Raman and laser-induced breakdown spectroscopy make it possible to constrain the genesis and evolution of apatite through time. Apatite in the glimmerite-carbonatite series formed by igneous processes. An increase in rare earth elements (REE) content during apatite deposition can be explained by re-equilibration of early apatite (via sub-solidus diffusion at the magmatic stage) with a fresh carbonatitic magma enriched in these elements. This late carbonatite emplacement has been known as a major contributor to the overall P and REE endowment of the system and is likely connected to fenitization and alkali-rich fluids. These fluids - enriched in REE - would have interacted with apatite in the fenite, resulting in an increase in REE content through coupled dissolution-reprecipitation processes. Finally, a marked decrease in LREE is observed in apatite hosted by fenite. It highlights the alteration of apatite by a REE-poor fluid during a late-magmatic/hydrothermal stage. Regarding the potential for REE exploitation, geochemical data combined with an estimation of the reserves indicate a sub-economic potential of REE to be exploited as by-products of phosphate mining. Spectroscopic analyses further provide helpful data for exploration, by determining the P and REE distribution and the enrichment in carbonatite and within apatite.
DS1998-1167
1998
Hohndorf, A.Pivec, E., Ulrych, J., Hohndorf, A., Rutsek, J.Melilitic rocks from northern Bohemia: geochemistry and mineralogyNeues Jahr. Min. Abh., Vol. 173, No. 2, pp. 119-154.GlobalMelilites
DS1999-0012
1999
Hohndorf, A.Andrade, F.R.D., Moller, P., Hohndorf, A.The effect of hydrothermal alteration Strontium neodymium isotopic signatures of the Barra do Itapirapua carbonatiteJournal of Geology, Vol. 107, No. 2, Mar. pp. 177-92.BrazilGeochronology, Carbonatite
DS2002-0901
2002
Hohne, J.Kruger, F., Scherbaum, F., Rosa, J.W.C., Kind, R., Zetsche, F., Hohne, J.Crustal and upper mantle structure in the Amazon region ( Brasil) determined with broadband mobile stations.Journal of Geophysical Research, Oct. 29, 10.1029/2001JB000598.BrazilGeophysics - seismics, Tectonics
DS2002-0902
2002
Hohne, J.Kruger, F., Scherbaum, F., Rosa, J.W.C., Kind, R., Zetsche, F., Hohne, J.Crustal and upper mantle structure in the Amazon region ( Brazil) determined with broadband mobile stations.Journal of Geophysical Research, Vol. 107, 10, ETE 17 DOI 10.1029/2001JB000598BrazilGeophysics - seismics, Tectonics
DS200612-0596
2005
Hoink, T.Hoink, T., Schmalzl, J., Hansen, U.Formation of compositional structures by sedimentation in vigorous convection.Physics of the Earth and Planetary Interiors, Vol. 153, 1-3, pp. 11-20.MantleConvection, tectonics
DS200812-0481
2008
Hoink, T.Hoink, T., Lenardic, A.Three dimensional mantle convection simulations with a low viscosity asthenosphere and the relationship between heat flow and the horizontal length scaleGeophysical Research Letters, Vol. 35, 10, May 28, L10304MantleConvection
DS200812-0641
2008
Hoink, T.Lee, C-T A., Luffi, P., Hoink, T., Li, Z-X.,A., Lenardic, A.The role of serpentine in preferential craton formation in the late Archean by lithosphere underthrusting.Earth and Planetary Science Letters, Vol. 269, 1-2, May 15, pp. 96-104.MantleGeochronology - cratons
DS201212-0304
2012
Hoink, T.Hoink, T., Lenardic, A., Richards, M.Depth dependent viscosity and mantle stress amplification: implicaions for the role of the asthenosphere in maintaining plate tectonics.Geophysical Journal International, in press availableMantleConvection
DS201909-2058
2019
Hoink, T.Lenardic, A., Weller, M., Hoink, T., Seales, J.Toward a boot strap hypothesis of plate tectonics: feedbacks between plates, the asthenosphere, and the wavelength of mantle convection.Physics of the Earth and Planetary Interiors, in press avaialable, 72p. PdfMantleplate tectonics

Abstract: The solid Earth system is characterized by plate tectonics, a low viscosity zone beneath plates (the asthenosphere), and long wavelength flow in the convecting mantle. We use suites of numerical experiments to show: 1) How long wavelength flow and the operation of plate tectonics can generate and maintain an asthenosphere, and 2) How an asthenosphere can maintain long wavelength flow and plate tectonics. Plate subduction generates a sub-adiabatic temperature gradient in the mantle which, together with temperature-dependent viscosity, leads to a viscosity increase from the upper to the lower mantle. This allows mantle flow to channelize in a low viscosity region beneath plates (an asthenosphere forms dynamically). Flow channelization, in turn, stabilizes long wavelength convection. The degree of dynamic viscosity variations from the upper to the lower mantle increases with the wavelength of convection and drops toward zero if the system transitions from plate tectonics to a single plate planet. The plate margin strength needed to initiate that transition increases for long wavelength cells (long wavelength flow allows plate tectonics to exist over a wider range of plate margin strength). The coupled feedbacks allow for a linked causality between plates, the asthenosphere, and the wavelength of mantle flow, with none being more fundamental than the others and the existence of each depending on the others. Under this hypothesis, the asthenosphere is defined by an active process, plate tectonics, which maintains it and is maintained by it and plate tectonics is part of an emergent, self-sustaining flow system that bootstraps itself into existence.
DS201910-2279
2019
Hoink, T.Lenardic, A., Weller, M.B., Seales, J., Hoink, T.Toward a boot strap hypothesis of plate tectonics: feedbacks between plate tectonics, the asthenosphere, and the wavelength of mantle convection.Physics of the Earth and Planetary Interiors, in press available, 57p. PdfMantleplate tectonics

Abstract: The solid Earth system is characterized by plate tectonics, a low viscosity zone beneath plates (the asthenosphere), and long wavelength flow in the convecting mantle. We use suites of numerical experiments to show: 1) How long wavelength flow and the operation of plate tectonics can generate and maintain an asthenosphere, and 2) How an asthenosphere can maintain long wavelength flow and plate tectonics. Plate subduction generates a sub-adiabatic temperature gradient in the mantle which, together with temperature-dependent viscosity, leads to a viscosity increase from the upper to the lower mantle. This allows mantle flow to channelize in a low viscosity region beneath plates (an asthenosphere forms dynamically). Flow channelization, in turn, stabilizes long wavelength convection. The degree of dynamic viscosity variations from the upper to the lower mantle increases with the wavelength of convection and drops toward zero if the system transitions from plate tectonics to a single plate planet. The plate margin strength needed to initiate that transition increases for long wavelength cells (long wavelength flow allows plate tectonics to exist over a wider range of plate margin strength). The coupled feedbacks allow for a linked causality between plates, the asthenosphere, and the wavelength of mantle flow, with none being more fundamental than the others and the existence of each depending on the others. Under this hypothesis, the asthenosphere is defined by an active process, plate tectonics, which maintains it and is maintained by it and plate tectonics is part of an emergent, self-sustaining flow system that bootstraps itself into existence.
DS201911-2540
2019
Hoink, T.Lenardic, A., Weller, M.B., Hoink, T., Seales, J. Toward a boot strap hypothesis of plate tectonics: feedbacks between plates, the asthenosphere, and the wavelength of mantle convection.Physics of the Earth and Planetary Interiors, in press 10.1016/j.pepi.2019.106299 18p. PdfMantleconvection

Abstract: The solid Earth system is characterized by plate tectonics, a low viscosity zone beneath plates (the asthenosphere), and long wavelength flow in the convecting mantle. We use suites of numerical experiments to show: 1) How long wavelength flow and the operation of plate tectonics can generate and maintain an asthenosphere, and 2) How an asthenosphere can maintain long wavelength flow and plate tectonics. Plate subduction generates a sub-adiabatic temperature gradient in the mantle which, together with temperature-dependent viscosity, leads to a viscosity increase from the upper to the lower mantle. This allows mantle flow to channelize in a low viscosity region beneath plates (an asthenosphere forms dynamically). Flow channelization, in turn, stabilizes long wavelength convection. The degree of dynamic viscosity variations from the upper to the lower mantle increases with the wavelength of convection and drops toward zero if the system transitions from plate tectonics to a single plate planet. The plate margin strength needed to initiate that transition increases for long wavelength cells (long wavelength flow allows plate tectonics to exist over a wider range of plate margin strength). The coupled feedbacks allow for a linked causality between plates, the asthenosphere, and the wavelength of mantle flow, with none being more fundamental than the others and the existence of each depending on the others. Under this hypothesis, the asthenosphere is defined by an active process, plate tectonics, which maintains it and is maintained by it and plate tectonics is part of an emergent, self-sustaining flow system that bootstraps itself into existence.
DS1983-0267
1983
Hoinkes, G.Gunter, W.D., Pajari, G.E., Hoinkes, G., Trembath, L.T.Mineral Flow Layering in the Leucite Hills VolcanicsGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC)/CGU, Vol. 8, ABSTRACT VOLUME, P. A32. ( abstract.)United States, Wyoming, Rocky MountainsLeucite, Wyomingite, Orendite
DS1990-0612
1990
Hoinkes, G.Gunter, W.D., Hoinkes, G., Ogden, P., Pajari, G.E.Origin of leucite rich and sanidine roch flow layers in the Leucite Hills volcanic field, WyomingJournal of Geophysical Research, Vol. 95, No. B 10, September 10, pp. 15, 911-15, 928WyomingLeucite, Lamproite -orendite
DS200612-0416
2005
Hoinkes, G.Fritz, H., Tenczer, V., Hauzenberger, C.A., Wallbrecher, E., Hoinkes, G., Muhongo, S.Central Tanzanian tectonic map: a step forward to decipher Proterozoic structural events.Tectonics, Vol. 24, 6, TC6013. 10.1029/2005 TC001796Africa, TanzaniaTectonics
DS200612-1076
2006
Hoinkes, G.Perraki, M., Proyer, A., Mposkos, E., Kaindl, R., Hoinkes, G.Raman micro spectroscopy on diamond, graphite and other carbon polymorphs from the ultrahigh pressure metamorphic Kimi Complex of the Rhodope metamorphic province.Earth and Planetary Science Letters, Vol. 241, 3-4, pp. 672-685.Europe, GreeceUHP
DS201012-0601
2010
Hoinkes, G.Proyer,A., Krenn, K., Hoinkes, G.Open system precipitation - a new way to explain crystallographically oriented precipitates/exsolutions in mineral from high-T/high-P rocks.International Mineralogical Association meeting August Budapest, abstract p. 211.Europe, Greece, BulgariaUHP Rhodope Mountains
DS201212-0724
2012
Hoinkes, G.Tenczer, V., Hauzenberger, Ch., Fritz, H., Hoinkes, G., Muhongo, S., Klotzli, U.Crustal age domains and metamorphic reworking of the deep crust in northern central Tanzania: a U Pb zircon and monazite study.Mineralogy and Petrology, in press availableAfrica, TanzaniaCraton, geochronology
DS201312-0218
2013
Hoinkes, G.Dobrzhinetskaya, L., Faryad, S.W., Hoinkes, G.Mineral transformations in HP-UHP metamorphic terranes.Journal of Metamorphic Geology, Vol. 31, 1, pp. 3-4.MantleUHP
DS201312-0260
2012
Hoinkes, G.Faryad, S.W., Dobrzhinetskaya, L., Hoinkes, G., Zhang, J.Ultrahigh pressure and high-pressure metamorphic terrances in orogenic belts: reactions, fluids and geological processes.Gondwana Research, Vol. 23, 4, pp. 841-MantleUHP
DS201312-0907
2013
Hoinkes, G.Teneczer, V., Hauzenberger, Ch., Fritz, H., Hoinkes, G., Mubongo, S., Klotzli, U.Crustal age domains and metamorphic reworking of the deep crust in northern central Tanzania: a U/Pb zircon and monazite age study.Mineralogy and Petrology, Vol. 107, pp. 679-707.Africa, TanzaniaGeochronology
DS1984-0360
1984
Hoist, T.B.Hoist, T.B.Evidence for Nappe Development During the Early Proterozoic penokean Orogeny, Minnesota.Geology, Vol. 12, No. 3, PP. 135-138.GlobalMid-continent
DS1996-1092
1996
Hoisteen, B.Pedersen, L.E., Holm, P.M., Hoisteen, B.Plume related magmatism on the margin of the Baltic shields: geochemistry and isotopic signatures -dykesInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 356.GlobalGeochemistry, Proterozoic dyke swarm
DS200412-0843
2004
Hokada, T.Hokada, T., Misawa, K., Yokoyama, K., Shiraishi, K., Yamaguchi, A.SHRIMP and electron microprobe chronology of UHT metamorphism in the Napier Complex, East Antarctica implications for zircon groContributions to Mineralogy and Petrology, Vol. 147, 1, pp. 1-20.AntarcticaGeochronology
DS1993-0685
1993
Hoke, L.Hoke, L., Lamb, S., Entenmann, J.Volcanic rocks from the Bolivian Altiplano: insights into crustalstructure, contamination, and magma genesis: comment and replyGeology, Vol. 21, No. 12, December pp. 1147-1149BoliviaTectonics, Magma
DS1997-0581
1997
Hoke, L.Kennan, L., Lamb, S.H., Hoke, L.High altitude paleosurfaces in the Bolivian Andes: evidence for late Cenozoic surface upliftWiddowson, M. Paleosurfaces, Geological Society of London, No. 120, pp. 307-323BoliviaCentral Andes, Tectonics
DS1997-0646
1997
Hoke, L.Lamb, S., Hoke, L.Origin of the high pressurelateau in the Central Andes, Bolivia, South AmericaTectonics, Vol. 16, No. 4, August pp. 623-49BoliviaBolivian Altiplano, chronostratigraphy, tectonics, Structure, Tambo Tambilla, deformation, crustal
DS2000-0417
2000
Hoke, L.Hoke, L., Lamb, S., Poreda, R.J.Southern limit of mantle derived geothermal helium emissions in Tibet: implications for lithospheric ...Earth and Planetary Science Letters, Vol. 180, No. 3-4, pp.297-308.Tibet, MantleGeothermometry
DS1989-0654
1989
Ho-kwang MaoHo-kwang MaoNew optical transitions in type 1A diamonds at very high stressesCarnegie Institution, Annual Report of the Director of the Geophysical, No. 2150, July 1-1988 -June 30, 1989 pp. 105-108GlobalDiamond morphology, Type 1A diamonds
DS200812-0482
2008
Holbig, E.S.Holbig, E.S., Grove, T.L.Mantle melting beneath the Tibetan Plateau: experimental constraints on ultrapotassic magmatism.Journal of Geophysical Research, Vol. 113, B4, B04210Asia, TibetMelting
DS201312-0339
2013
Holbig, E.S.Grove, T.L., Holbig, E.S., Barr, J.A., Till, C.B., Krawczynski, M.J.Inclusions in halite - evidence of mixing of evaporite xenoliths and kimberlites of Udachnaya -East pipe (Siberia).Contributions to Mineralogy and Petrology, Vol. 166, pp. 887-910.MantleMelting
DS201312-0342
2013
Holbig, E.S.Grove, T.L., Holbig, E.S., Barr, J.A., Till, C.B., Krawczynski, M.J.Melts of garnet lherzolite: experiments, models and comparison to melts of pyroxenite and carbonated lherzolite.Contributions to Mineralogy and Petrology, Vol. 166, pp. 887-910.South America, BrazilGeochronology (~91to 78)
DS1940-0152
1947
Holbrook, D.F.Holbrook, D.F.A Brookite Deposit in Hot Spring County, ArkansawArkansaw RESOURCES AND DEVEL. COMM. DIV. GEOLOGY Bulletin., No. 11, 21P.United States, Gulf Coast, Arkansas, Hot Spring CountyBrookite
DS1940-0179
1948
Holbrook, D.F.Holbrook, D.F.Molybdenum in Magnet Cove, ArkansawArkansaw RESOURCES AND DEVEL. COMM. GEOLOGY Bulletin., No. 12, 16P.United States, Gulf Coast, Arkansas, Hot Spring CountyMolybdenum
DS1950-0025
1950
Holbrook, D.F.Fryklund, V.C.Jr., Holbrook, D.F.Titanium Ore Deposits of Hot Spring County, ArkansawArkansaw RESOURCES AND DEVEL. COMM. DIV. GEOLOGY Bulletin., No. 16, 173P.United States, Gulf Coast, Arkansas, Hot Spring CountyTitanium
DS1960-0250
1962
Holbrook, D.F.Holbrook, D.F.The Geology of Magnet CoveMississippi Geological Society, PP. 10-11.United States, Gulf Coast, Arkansas, Hot Spring CountyGeology
DS1994-0783
1994
Holbrook, D.F.Holbrook, D.F.Investigation of the Crater of Diamonds State Park(Prairie Creek)diamond deposit.Geological Society of America Abstracts, Vol. 26, No. 1, February p. 9. AbstractArkansasLamproite, Tonnages
DS1999-0313
1999
Holbrook, J.Holbrook, J., Schumm, S.A.Geomorphic and sedimentary response of rivers to tectonic deformation:recognizing subtle epirogeneticTectonophysics, Vol. 305, No. 1-3, May 10, pp. 287-306.GlobalGeomorphology - modern, ancient, Tectonics - rivers
DS1993-0686
1993
Holbrook, J.M.Holbrook, J.M.Evidence and potential tectonic origin of regional intraplate deformation throughout the early Cretaceous United States, western interiorGeological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A70 abstract onlyMontana, New MexicoTectonics
DS1993-0687
1993
Holbrook, W.S.Holbrook, W.S., Kelemen, P.B.Large igneous province on the United States Atlantic margin and implications for magmatism during continental breakupNature, Vol. 364, July 29, pp. 433-436AppalachiaGeophysics -magnetics, Hot spots, rifting
DS1998-0631
1998
Holbrook, W.S.Holbrook, W.S.Magmatism at volcanic rifted margins: a potential contributor to continental growth.Geological Society of America (GSA) Annual Meeting, abstract. only, p.A244.GreenlandUnderplating - margins
DS1991-1257
1991
HolcombeOliver, N.H.S., Holcombe, Hill, PearsonTectono-metamorphic evolution of the Mary Kathleen fold belt: a reflection of mantle plume processes?Australian Journal of Earth Sciences, Vol. 38, No. 4, pp. 425-55.AustraliaCrustal evolution - not specific to diamond
DS1990-0711
1990
Holden, C.Holden, C.Spontaneous order, evolution and lifeScience, Vol. 247, No. 4950, March 30, pp. 1543-1544GlobalEvolution, Dynamic systems
DS1930-0069
1931
Holden, E.F.Kraus, E.H., Holden, E.F.Gems and Gem Materials. #2New York: Mcgraw Hill, 260P.GlobalDiamond Morphology, Crystallography, Kimberley
DS201012-0283
2009
Holden, E.J.Holden, E.J., Moss, S., Russell, J.K., Dentith, M.C.An image analysis method to determine crystal size distributions of olivine in kimberlite.Computational Geosciences, Vol. 13, 3, Sept. pp. 255-268.TechnologyOlivine, morphology
DS201907-1550
2019
Holden, E-J.Holden, E-J., Liu, W., Horrocks, T., Wang, R., Wedge, D., Duuring, P., Beardsmore, T.GeoDocA - fast analysis of geological content in mineral exploration reports: a text mining approach. Not specific to diamondOre Geology Reviews, in press available, 20p.AustraliaAnalysis system
DS1990-1096
1990
Holden, P.Neal, C.R., Taylor, L.A., Davidson, J.P., Holden, P., HallidayEclogites with oceanic crustal and mantle signatures from the BellsbankEarth and Planetary Science Letters, Vol. 99, pp. 362-379South AfricaEclogites, Bellsbank -geochronology
DS1995-1092
1995
Holden, P.Leventhal, J.A., Reid, M.R., Montana, A., Holden, P.Mesozoic invasion of crust by Mid Ocean Ridge Basalt (MORB) source asthenopheric magmas. U.S.Cordilleran interiorGeology, Vol. 23, No. 5, May pp. 399-402California, Basin and Range, CordilleraMantle lithosphere, Mid Ocean Ridge Basalt (MORB).
DS200612-0540
2005
Holden, P.Harrison, T.M., Blichert-Toft, J., Muller, W., Albarede, F., Holden, P., Mojzsis, S.J.Heterogeneous Hadean hafnium: evidence of continental crust 4.4 to 4.5 Ga.Science, Vol. 310, 5736 Dec. 23, pp. 1947-1949.MantleGeochronology
DS200612-0541
2006
Holden, P.Harrison, T.M., McCulloch, M.T., Blichert-Toft, J., Albarede, F., Holden, P., Mojzsis, S.J.Further Hf isotope evidence for Hadean continental crust.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 14, abstract only.MantleGeochronology
DS201212-0018
2012
Holden, 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
DS1940-0087
1944
Holden, R.J.Holden, R.J.The Punch Jones and other Appalachian DiamondsVirginia Polytech. Institute Eng. Exp. Ste. Ser., No. 56, 36P.United States, Alabama, Georgia, Kentucky, Appalachia, North CarolinaRussell County, Hall County, White County, Clayton
DS200512-0441
2005
Holden, T.Holden, T., Serearuno, M.A hybrid artificial experience approach for improving yield in precious stone manufacturing.Journal of Intelligent Manufacturing, Vol. 16, 1, Feb. pp. 21-38. Kluwer Academic Publ.Diamond cutting
DS201312-0398
2013
Holder, A.Holder, A., Rogers, A.J., Bartlett, P.J., Keyter, G.J.Review of mud rush mitigation on Kimberley's old scraper drift block caves. DutoitspanSouth African Institute of Mining and Metallurgy, Vol. 113, July, pp. 529-538.Africa, South AfricaMining
DS201605-0852
2016
Holder, A.Judeel, G., Swaneoel, T., Holder, A., Swarts, B., Van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine No. 1 shaft underneath the existing operating shaft.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 301-316.Africa, South AfricaDeposit - Cullinan
DS201605-0910
2016
Holder, A.Tukker, H., Holder, A., Swarts, B., Van Strijp, T., Grober, E.The CCUT black cave design for the Culli nan diamond mine.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 57-70.Africa, South AfricaDeposit - Cullinan
DS201605-0911
2016
Holder, A.Tukker, H., Marsden, H., Holder, A., Swarts, B., Van Strijp, T., Grobler, E., Engelbrecht, F.Koffiefontein diamond mine sublevel cave design.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 129-142.Africa, South AfricaDeposit - Koffiefontein
DS201612-2308
2016
Holder, A.Judeel, G., Swanepoel, T., Holder, A., Swarts, B., van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine no. 1 shaft underneath the existing operating shaft, with emphasis on rock engineering considerations.Journal of South African Institute of Mining and Metallurgy, Vol. 116, Aug. pp. 745-753.Africa, South AfricaDeposit - Cullinan

Abstract: In 2012, Cullinan Diamond Mine began an expansion programme with the shaft deepening and development of access to the C-Cut 1 block at approximately 839 m below surface. The expansion programme is funded by a combination of bank loans and retained operating profit generated by the mine. Continuous production during deepening of the No. 1 Shaft, which is the rock hoisting shaft, was therefore critical for sustainability and efficiency as well as overall funding of the project. The deepening method, support design and verification, as well as learning outcomes pertaining to the extension of the No. 1 Shaft underneath the existing operating shaft are summarized, with emphasis on the importance of gaining some understanding of the shaft's host rock mass.
DS201709-2007
2016
Holder, A.Judeel, G., Swanepoel, T., Holder, A., Swarts, B., van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine No. 1 shaft underneath the existing operating shaft, with emphasis on rock engineering considerations.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 745-752.Africa, South Africadeposit - Cullinan

Abstract: In 2012, Cullinan Diamond Mine began an expansion programme with the shaft deepening and development of access to the C-Cut 1 block at approximately 839 m below surface. The expansion programme is funded by a combination of bank loans and retained operating profit generated by the mine. Continuous production during deepening of the No. 1 Shaft, which is the rock hoisting shaft, was therefore critical for sustainability and efficiency as well as overall funding of the project. The deepening method, support design and verification, as well as learning outcomes pertaining to the extension of the No. 1 Shaft underneath the existing operating shaft are summarized, with emphasis on the importance of gaining some understanding of the shaft's host rock mass.
DS201709-2066
2016
Holder, A.Tukker, H., Holder, A., Swarts, B., van Strijp, T., Grobler, E.The CCUT block cave design for Culli nan diamond mine.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 715-723.Africa, South Africadeposit - Cullinan
DS201910-2265
2019
Holder, R.Holder, R., Viete, D.R., Brown, M., Johnson, T.E.Metamorphism and evolution of plate tectonics.Nature, Vol. 572, 7769, pp. 1-4.Mantleplate tectonics

Abstract: Earth’s mantle convection, which facilitates planetary heat loss, is manifested at the surface as present-day plate tectonics1. When plate tectonics emerged and how it has evolved through time are two of the most fundamental and challenging questions in Earth science1,2,3,4. Metamorphic rocks—rocks that have experienced solid-state mineral transformations due to changes in pressure (P) and temperature (T)—record periods of burial, heating, exhumation and cooling that reflect the tectonic environments in which they formed5,6. Changes in the global distribution of metamorphic (P, T) conditions in the continental crust through time might therefore reflect the secular evolution of Earth’s tectonic processes. On modern Earth, convergent plate margins are characterized by metamorphic rocks that show a bimodal distribution of apparent thermal gradients (temperature change with depth; parameterized here as metamorphic T/P) in the form of paired metamorphic belts5, which is attributed to metamorphism near (low T/P) and away from (high T/P) subduction zones5,6. Here we show that Earth’s modern plate tectonic regime has developed gradually with secular cooling of the mantle since the Neoarchaean era, 2.5 billion years ago. We evaluate the emergence of bimodal metamorphism (as a proxy for secular change in plate tectonics) using a statistical evaluation of the distributions of metamorphic T/P through time. We find that the distribution of metamorphic T/P has gradually become wider and more distinctly bimodal from the Neoarchaean era to the present day, and the average metamorphic T/P has decreased since the Palaeoproterozoic era. Our results contrast with studies that inferred an abrupt transition in tectonic style in the Neoproterozoic era (about 0.7 billion years ago1,7,8) or that suggested that modern plate tectonics has operated since the Palaeoproterozoic era (about two billion years ago9,10,11,12) at the latest.
DS201909-2046
2019
Holder, R.M.Holder, R.M., Viete, D.R., Brown, M., Johnson, T.E.Metamorphism and the evolution of plate tectonics.Nature, doi.org/10.1038/ s41586-019-1462-2 2p.Mantleplate tectonics

Abstract: Earth’s mantle convection, which facilitates planetary heat loss, is manifested at the surface as present-day plate tectonics1. When plate tectonics emerged and how it has evolved through time are two of the most fundamental and challenging questions in Earth science1,2,3,4. Metamorphic rocks—rocks that have experienced solid-state mineral transformations due to changes in pressure (P) and temperature (T)—record periods of burial, heating, exhumation and cooling that reflect the tectonic environments in which they formed5,6. Changes in the global distribution of metamorphic (P, T) conditions in the continental crust through time might therefore reflect the secular evolution of Earth’s tectonic processes. On modern Earth, convergent plate margins are characterized by metamorphic rocks that show a bimodal distribution of apparent thermal gradients (temperature change with depth; parameterized here as metamorphic T/P) in the form of paired metamorphic belts5, which is attributed to metamorphism near (low T/P) and away from (high T/P) subduction zones5,6. Here we show that Earth’s modern plate tectonic regime has developed gradually with secular cooling of the mantle since the Neoarchaean era, 2.5 billion years ago. We evaluate the emergence of bimodal metamorphism (as a proxy for secular change in plate tectonics) using a statistical evaluation of the distributions of metamorphic T/P through time. We find that the distribution of metamorphic T/P has gradually become wider and more distinctly bimodal from the Neoarchaean era to the present day, and the average metamorphic T/P has decreased since the Palaeoproterozoic era. Our results contrast with studies that inferred an abrupt transition in tectonic style in the Neoproterozoic era (about 0.7 billion years ago1,7,8) or that suggested that modern plate tectonics has operated since the Palaeoproterozoic era (about two billion years ago9,10,11,12) at the latest.
DS2001-0775
2001
Holdsworth, R.Miller, J., Holdsworth, R., Buick, L., Hand, M.Continental reactivation and reworkingGeological Society of London, No. 184, 450p. approx. $ 142.00GlobalBook - ad, Structure, faulting, Tectonics, crust, lithosphere
DS1998-0632
1998
Holdsworth, R.E.Holdsworth, R.E., et al.Continental transpressional tectonics and transtensional tectonicsGeological Society of London Spec. Pub, No. 135, 360p. $ 132.00United States, Dead Sea, China, EuropeBook - ad, Tectonics
DS2001-0483
2001
Holdsworth, R.E.Holdsworth, R.E., Strachan, R.A., Magloughlin, KnipeThe nature and tectonic significance of fault zone weakeningGeological Society of London - Book, No. 186, 328p. approx. $120.00 United StatesGlobalBook - ad, Structure, faulting, tectonics
DS2001-0484
2001
Holdsworth, R.E.Holdsworth, R.E., Strachan, R.A., Magloughlin, KnipeThe nature and tectonic significance of fault zone weakeningGeological Society of London, No. 186, 350p.GlobalBook - table of contents, Tectonics - deformation, fault systems
DS2001-0776
2001
Holdsworth, R.E.Miller, J.A., Holdsworth, R.E., Buick, I.S., Hand, M.Continental reactivation and reworkingGeological Society of London, No. 184, 400p.GlobalBook - table of contents, Tectonics - basement orogeny
DS2002-0316
2002
Holdsworth, R.E.Cook, C.A., Holdsworth, R.E., Styles, M.T.The emplacement of peridotites and associated oceanic rocks from the Lizard Complex, southwest England.Geological Magazine, Vol.139,1,pp.27-45., Vol.139,1,pp.27-45.EnglandMantle peridotites, metamorphism, Tectonothermal events
DS2002-0317
2002
Holdsworth, R.E.Cook, C.A., Holdsworth, R.E., Styles, M.T.The emplacement of peridotites and associated oceanic rocks from the Lizard Complex, southwest England.Geological Magazine, Vol.139,1,pp.27-45., Vol.139,1,pp.27-45.EnglandMantle peridotites, metamorphism, Tectonothermal events
DS200812-0121
2008
Hole, J.Bodnar, R.J., Azbej, T., Becker, S., Cannatelli, C., Fall, A., Hole, J., Severs, M.The whole Earth geohydrologic cycle.Goldschmidt Conference 2008, Abstract p.A91.MantleWater
DS1991-0725
1991
Hole, M.J.Hole, M.J., Rogers, G., Saunders, A.D., Storey, M.Relation between alkalic volcanism and slab-window formationGeology, Vol. 19, No. 6, June pp. 657-660California, British ColumbiaAlkalic volcanism., Tectonics, Geochemistry
DS1992-1485
1992
Hole, M.J.Storey, B.C., Alabaster, T., Hole, M.J., Pankhurst, R.J., Wever, H.E.Role of subduction-plate boundary forces during the initial stages of Gondwana break-up: evidence from the Proto-Pacific margin of Antarctica.Geological Society Special Publication, Magmatism and the Causes of Continental, No. 68, pp. 149-163.AntarcticaTectonics, Subduction
DS1993-0688
1993
Hole, M.J.Hole, M.J., Kempton, P.D., Millar, I.L.Trace element and isotopic characteristics of small degree melts of theasthenosphere: evidence from the alkalic basalts of the Antarctic Peninsula.Chemical Geology, Vol. 109, pp. 51-68.AntarcticaMantle melts
DS1995-0814
1995
Hole, M.J.Hole, M.J., Saunders, A.D., Rogers, G., Sykes, M.A.The relationship between alkaline magmatism, lithospheric extension and slab window formation...Geological Society of London Special Paper, Volcanism Association extension consuming, No. 81, pp. 265-285.AntarcticaPlate margins, Slab subduction
DS1996-0642
1996
Hole, M.J.Hole, M.J., Saunders, A.D.The generation of small melt fractions in truncated melt columns:constraints from magma above slab windowsMineralogical Magazine, Vol. 60, No. 1, Feb pp. 173-190GlobalMagmatic processes, Slab windows, subduction
DS201905-1036
2019
Holems, A.K.Grewal, D.S., Dasgupta, R., Holems, A.K., Costin, G., Li, Y., Tsuno, K.The fate of nitrogen during core-mantle separation on Earth.Geochimica et Cosmochimica Acta, Vol. 251, pp. 87-115.Mantlenitrogen

Abstract: Nitrogen, the most dominant constituent of Earth’s atmosphere, is critical for the habitability and existence of life on our planet. However, its distribution between Earth’s major reservoirs, which must be largely influenced by the accretion and differentiation processes during its formative years, is poorly known. Sequestration into the metallic core, along with volatility related loss pre- and post-accretion, could be a critical process that can explain the depletion of nitrogen in the Bulk Silicate Earth (BSE) relative to the primitive chondrites. However, the relative effect of different thermodynamic parameters on the alloy-silicate partitioning behavior of nitrogen is not well understood. Here we present equilibrium partitioning data of N between alloy and silicate melt () from 67 new high pressure (P?=?1-6?GPa)-temperature (T?=?1500-2200?°C) experiments under graphite saturated conditions at a wide range of oxygen fugacity (logfO2?~??IW -4.2 to -0.8), mafic to ultramafic silicate melt compositions (NBO/T?=?0.4 to 2.2), and varying chemical composition of the alloy melts (S and Si contents of 0-32.1?wt.% and 0-3.1?wt.%, respectively). Under relatively oxidizing conditions (~?IW -2.2 to -0.8) nitrogen acts as a siderophile element ( between 1.1 and 52), where decreases with decrease in fO2 and increase in T, and increases with increase in P and NBO/T. Under these conditions remains largely unaffected between S-free conditions and up to ~17?wt.% S content in the alloy melt, and then drops off at >~20?wt.% S content in the alloy melt. Under increasingly reduced conditions (<~?IW -2.2), N becomes increasingly lithophile ( between 0.003 and 0.5) with decreasing with decrease in fO2 and increase in T. At these conditions, fO2 along with Si content of the alloy under the most reduced conditions (<~?IW -3.0), is the controlling parameter with T playing a secondary role, while, P, NBO/T, and S content of the alloy have minimal effects. A multiple linear least-squares regression parametrization for based on the results of this study and previous studies suggests, in agreement with the experimental data, that fO2 (represented by Si content of the alloy melt and FeO content of the silicate melt), followed by T, has the strongest control on . Based on our modeling, to match the present-day BSE N content, impactors that brought N must have been moderately to highly oxidized. If N bearing impactors were reduced, and/or there was significant disequilibrium core formation, then the BSE would be too N-rich and another mechanism for N loss, such as atmospheric loss, would be required.
DS1995-2008
1995
Holl, A.Volker, F., Holl, A., Alibert, C.Late Miocene to Quaternary volcanics from Serbia and Macedonia.. new lamproite province.Terra Nova, Abstract Vol., p. 336.Serbia, MacedoniaLamproite
DS200412-0021
2004
Holl, A.Altherr, R., Meyer, H.P., Holl, A., Volker, F., Alibert, C., McCulloch, M.T., Majer, V.Geochemical and Sr Nd Pb isotopic characteristics of Late Cenozoic leucite lamproites from the East European Alpine belt ( MacedContributions to Mineralogy and Petrology, Vol. 147, 1, pp. 58-73.Europe, MacedoniaLamproite, geodynamics
DS2003-1300
2003
Holl, C.M.Smyth, J.R., Holl, C.M., Frost, D.J., Jacobsen, S.D., Langenhorst, F.Structural systematics of hydrous ring woodite and water in Earth's interiorAmerican Mineralogist, Vol. 88, 10, Oct. pp. 1402-7.MantleMineralogy
DS200412-1863
2003
Holl, C.M.Smyth, J.R., Holl, C.M., Frost, D.J., Jacobsen, S.D., Langenhorst, F., McCammon, C.A.Structural systematics of hydrous ring woodite and water in Earth's interior.American Mineralogist, Vol. 88, 10, Oct. pp. 1402-7.MantleMineralogy
DS200612-1325
2006
Holl, C.M.Smyth, J.R., Frost, D.J., Nestola, F., Holl, C.M., Bromiley, G.Olivine hydration in the deep upper mantle: effects of temperature and silica activity.Geophysical Research Letters, Vol. 33, 15, August 16, L15301MantleMineral chemistry
DS200612-1326
2006
Holl, C.M.Smyth, J.R., Holl, C.M., Frost, D.J., Keppler, H., Nestola, F., Mierdel, K.Hydration of nominally anhydrous minerals: melt generation, physical properties, and dynamics of the upper mantle.International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p.102.MantleMelt generation
DS200712-0476
2007
Holl, C.M.Jacobsen, S.D., Van der Lee, S., Smyth, J.R., Holl, C.M.Detecting hydration in the Earth's mantle.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.187-188.MantleWater
DS200712-0477
2007
Holl, C.M.Jacobsen, S.D., Van der Lee, S., Smyth, J.R., Holl, C.M.Detecting hydration in the Earth's mantle.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.187-188.MantleWater
DS201612-2345
2016
Hollabaugh, C.L.Willford, G., Hollabaugh, C.L.Examination of diamond stability phase mantle indicator minerals from Leucite Hills, Sweetwater County, Wyoming and Crater of Diamonds State Park, Pike Count, Arkansas.Geological Society of America, Vol. 48, 3, 1p. AbstractUnited States, Wyoming, ArkansasDeposit - Leucite Hills, Diamond State Par
DS1990-1153
1990
Holladay, .S.Palacky, G.J., Holladay, .S., Walker, P.W.Use of inversion techniques in interpretation of helicopter electromagneticdat a for mapping quaternary sediments near Kapuskasing, Ontario CanadaSociety of Exploration Geophysicists, 60th. Annual Meeting held, San, Vol. 1, pp. 689-692. Extended abstractOntarioKapuskasing, Geophysics -electromagnetic
DS1991-1285
1991
Holladay, J.S.Palacky, G.J., Holladay, J.S., Walker, P.W.Mapping of Quaternary sediments near Kapuskasing, Ontario with a helicopter electromagnetic systemGeological Survey of Canada Forum held January 21-23, 1990 in Ottawa, p. 13 AbstractOntarioGeophysics -electromagnetic, Sediments
DS1992-1156
1992
Holladay, J.S.Palacky, G.J., Holladay, J.S., Walker, P.Inversion of helicopter electromagnetic dat a along the Kapuskasingtransect, OntarioGeological Survey of Canada Paper, No. 92-1E, pp. 177-184OntarioGeophysics, Kapuskasing Rift
DS1985-0294
1985
Holland, C.H.Holland, C.H.Lower Paleozoic of North Western and West Central AfricaWiley, Chichester., 512P.West Africa, Chad, Sierra LeoneReview, Synthesis Of Regional Geology
DS200512-0339
2005
Holland, G.Gilmour, J.D., Verchocsky, A.B., Fisenko, A.V., Holland, G., Turner, G.Xenon isotopes in size separated nanodiamonds from Efremovka: 129 Xe, Xe-P3 and Xe-P6.Geochimica et Cosmochimica Acta, Vol. 69, 16, Aug.15, pp. 4133-4148.TechnologyNanodiamonds, geochronology, degassing events
DS200712-0049
2007
Holland, G.Ballentine, C.J., Brandenburg, J.P., Van Keken, P.E., Holland, G.Seawater recycling into the deep mantle - and the source of 3He.Plates, Plumes, and Paradigms, 1p. abstract p. A56.MantleNoble gases
DS200812-0076
2008
Holland, G.Ballentine, C.J., Holland, G.What CO2 well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere.Philosophical Transactions Royal Society of London Series A Mathematical Physical and Engineering Sciences, Vol. 366, no. 1883, pp. 4183-4204.MantleNoble gases
DS1990-0712
1990
Holland, H.D.Holland, H.D.Review of the Report:The changing atmosphere: report of the Dahlem workshop held Berlin 1987American Journal of Science, Vol. 290, No. 1, January pp. 107-GlobalReview of Report, Changing atmosphere
DS1990-0713
1990
Holland, H.D.Holland, H.D., Beukes, N.J.A paleoweathering profile from griqualand West: evidence for a dramaticrise in atmospheric oxygen between 2.2 and 1.9 BYBP.American Journal of Science, Vol. 290-A, pp. 1-34.South AfricaGeomorphology
DS1991-1029
1991
Holland, H.D.Macfarlane, A.W., Holland, H.D.The timing of alkali metasomatism in paleosolsCanadian Mineralogist, Vol. 29, pt. 4, December pp. 1043-1050GlobalGeochronology, Precambrian paleosols
DS1995-0815
1995
Holland, H.D.Holland, H.D., Petersen, U.Living dangerously... earth, resources and environmentPrinceton University of Press, 600p. approx. $ 60.00GlobalBook -ad, Earth resources
DS1995-1637
1995
Holland, H.D.Rye, R., Kuo, P.H., Holland, H.D.Atmospheric carbon dioxide concentrations before 2.2 billion years agoNature, Vol. 378, Dec. 7, pp. 603-605MantleCarbon dioxide, Earth's history
DS1997-0514
1997
Holland, K.G.Holland, K.G., Ahrens, T.J.Melting of (magnesium, iron)(magnesium, iron)2 SiO4 at the core-mantle boundary of the earth.Science, Vol. 275, No. 5306, Mar. 14, pp. 1623-25.MantleMelting, Core-mantle boundary
DS201212-0759
2012
Holland, R.Waldie, C., Whyte, J., Holland, R.NI 43-101 The new version and what you need to know.PDAC Short course, March 7, ppt manualCanadaLegal - reports
DS201112-0441
2011
Holland, T.B.J.Holland, T.B.J., Powell, R.An improved and extended internally consistent thermodynamic data set for phases of petrological interest, involving a new equation of state for solids.Journal of Metamorphic Geology, in print availableMantleGeodynamics
DS1900-0669
1908
Holland, T.H.Holland, T.H.Sketch of the Mineral Resources of IndiaIndia Geological Survey Miscellaneous Report, 86P. PP. 63-65.IndiaMineral Resources
DS1910-0060
1910
Holland, T.H.Holland, T.H., Fermor, L.L.Mineral Production, 1904-1908: DiamondsIndia Geological Survey Records, Vol. 39, PP. 80-83.IndiaDiamond Occurrences
DS1981-0334
1981
Holland, T.J.B.Perkins, D., Holland, T.J.B., Newton, R.C.The Al2o3 Contents of Enstatite in Equilibrium with Garnet In the System Mgo Al2os Sio2 at 15-40kbar and 900-1, 600c.Contributions to Mineralogy and Petrology, Vol. 78, PP. 99-109.GlobalMineral Chemistry
DS200812-0915
2008
Holland, T.J.B.Powell, R., Holland, T.J.B.On thermobarometry.Journal of Metamorphic Geology, Vol. 26, 2, pp. 155-179.TechnologyGeothermometry
DS201112-0442
2011
Holland, T.J.B.Holland, T.J.B., Powell, R.An improved and extended internally consistent thermodynamic data set for phases of petrological interest, involving a new equation of state for solids.Journal of Metamorphic Geology, Special issue,TechnologyPetrology - dataset not specific to diamonds
DS201312-0399
2013
Holland, T.J.B.Holland, T.J.B., Hudson, N.F.C., Powell, R., Harte, B.How irreversible heat transport processes drive Earth's interdependent thermal, structural and chemical evolution.Journal of Petrology, Vol. 54, pp. 1901-1920.MantleGeothermometry
DS201412-0586
2014
Holland, T.J.B.Miller, W.G.R., Holland, T.J.B., Gibson, S.A.Multiple reaction oxygen barometry for mantle peridotite: an internally consistent thermodynamic model for reactions and garnet solid-solutions, with applications to the oxidation state of lithospheric mantle.Volcanic and Magmatic Studies Group meeting, Poster Held Jan. 6-8. See minsoc websiteMantleThermobarometry
DS201608-1424
2016
Holland, T.J.B.Miller, W.G.R., Holland, T.J.B., Gibson, S.A.Garnet and spinel oxybarometers: new internally consistent multi-equilibration temperatures models with applications to the oxidation state of the lithospheric mantle.Journal of Petrology, Vol. 57, 6, pp. 1199-1222.MantleGeobarometry

Abstract: New thermodynamic data for skiagite garnet (Fe3Fe23+Si3O12) are derived from experimental phase-equilibrium data that extend to 10 GPa and are applied to oxybarometry of mantle peridotites using a revised six-component garnet mixing model. Skiagite is more stable by 12 kJ mol-1 than in a previous calibration of the equilibrium 2 skiagite = 4 fayalite + ferrosilite + O2, and this leads to calculated oxygen fugacities that are higher (more oxidized) by around 1-1•5 logfO2 units. A new calculation method and computer program incorporates four independent oxybarometers (including 2 pyrope + 2 andradite + 2 ferrosilite = 2 grossular + 4 fayalite + 3 enstatite + O2) for use on natural peridotite samples to yield optimum logfO2 estimates by the method of least squares. These estimates should be more robust than those based on any single barometer and allow assessment of possible disequilibrium in assemblages. A new set of independent oxybarometers for spinel-bearing peridotites is also presented here, including a new reaction 2 magnetite + 3 enstatite = 3 fayalite + 3 forsterite + O2. These recalibrations combined with internally consistent PT determinations for published analyses of mantle peridotites with analysed Fe2O3 data for garnets, from both cratonic (Kaapvaal, Siberia and Slave) and circumcratonic (Baikal Rift) regions, provide revised estimates of oxidation state in the lithospheric mantle. Estimates of logfO2 for spinel assemblages are more reduced than those based on earlier calibrations, whereas garnet-bearing assemblages are more oxidized. Importantly, this lessens considerably the difference between garnet and spinel oxybarometry that was observed with previous published calibrations.
DS201702-0218
2016
Holland, T.J.B.Jennings, E.S., Holland, T.J.B., Shorttle, O., Gibson, S.The composition of melts from a heterogeneous mantle and origin of ferropicrite: application of a thermodynamic model.Journal of Petrology, In press available 22p.MantleEclogite, melting

Abstract: Evidence for chemical and lithological heterogeneity in the Earth’s convecting mantle is widely acknowledged, yet the major element signature imparted on mantle melts by this heterogeneity is still poorly resolved. In this study, a recent thermodynamic melting model is tested on a range of compositions that correspond to potential mantle lithologies (harzburgitic to pyroxenitic), to demonstrate its applicability over this compositional range, in particular for pyroxenite melting. Our results show that, despite the model’s calibration in peridotitic systems, it effectively reproduces experimental partial melt compositions for both Si-deficient and Si-excess pyroxenites. Importantly, the model accurately predicts the presence of a free silica phase at high pressures in Si-excess pyroxenites, indicating the activation of the pyroxene-garnet thermal divide. This thermal divide has a dominant control on solidus temperature, melt productivity and partial melt composition. The model is used to make new inferences on the link between mantle composition and melting behaviour. In silica-deficient and low-pressure (olivine-bearing) lithologies, melt composition is not very sensitive to source composition. Linearly varying the source composition between peridotite and basaltic pyroxenite, we find that the concentration of oxides in the melt tends to be buffered by the increased stability of more fusible phases, causing partial melts of even highly fertile lithologies to be similar to those of peridotite. An exception to this behaviour is FeO, which is elevated in partial melts of silica-deficient pyroxenite even if the bulk composition does not have a high FeO content relative to peridotite. Melt Al2O3 and MgO vary predominantly as a function of melting depth rather than bulk composition. We have applied the thermodynamic model to test the hypothesis that Fe-rich mantle melts such as ferropicrites are derived by partial melting of Si-deficient pyroxenite at elevated mantle potential temperatures. We show that the conspicuously high FeO in ferropicrites at a given MgO content does not require a high-Fe mantle source and is indeed best matched by model results involving around 0-20% melting of silica-deficient pyroxenite. A pyroxenite source lithology also accounts for the low CaO content of ferropicrites, whereas their characteristic low Al2O3 is a function of their high pressure of formation. Phanerozoic ferropicrites are exclusively located in continental flood basalt (CFB) provinces and this model of formation confirms that lithological heterogeneity (perhaps recycled oceanic crust) is present in CFB mantle sources.
DS201704-0629
2017
Holland, T.J.B.Jennings, E.S., Holland, T.J.B., Maclennan, J., Gibson, S.A.The composition of melts from a heterogeneous mantle and the origin of ferropicrite: application of a thermodynamic model.Journal of Petrology, Vol. 57, 11-12, pp. 2289-2310.MantleGeochemistry
DS200712-0144
2007
HollandaCarlson, 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
HollandaCarlson, 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
DS201902-0263
2018
Hollanda, M.H.Cavalcante, C., Hollanda, M.H., Vauchez, A., Kawata, M.How long can the middle crust remain partially molten during orogeny?Geology, Vol. 46, pp. 839-852.South America, Brazil, Africa, Congomelting

Abstract: Extensive partial melting of the middle to lower crustal parts of orogens, such as of the current Himalaya-Tibet orogen, significantly alters their rheology and imposes first-order control on their tectonic and topographic evolution. We interpret the late Proterozoic Araçuaí orogen, formed by the collision between the São Francisco (Brazil) and Congo (Africa) cratons, as a deep section through such a hot orogen based on U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon ages and Ti-in-zircon and Zr-in-rutile temperatures from the Carlos Chagas anatectic domain. This domain is composed of peraluminous anatexites and leucogranites that typically exhibit interconnected networks of garnet-rich leucosomes or a magmatic foliation. Zirconium-in-rutile temperatures range from 745 to 820 °C, and the average Ti-in-zircon temperature ranges from 712 to 737 °C. The geochronologic and thermometry data suggest that from 597 to 572 Ma this domain was partially molten and remained so for at least 25 m.y., slowly crystallizing between temperatures of ~815 and >700 °C. Significant crustal thickening must have occurred prior to 600 Ma, with initial continental collision likely before 620 Ma, a time period long enough to heat the crust to temperatures required for widespread partial melting at middle crustal levels and to favor a "channel flow" tectonic behavior.
DS200512-0442
2005
Hollanda, M.H.B.M.Hollanda, M.H.B.M., Pimentel, M.M., Oliveira, D.C., De Sa, E.F.J.Lithosphere - asthenosphere interaction and the origin of Cretaceous tholeiitic magmatism in northeastern Brazil: Sr Nd Pb isotopic evidence.Lithos, Advanced in press,South America, BrazilRio Ceara Mirim dike, magmatism
DS201412-0623
2014
Hollanda, M.H.B.M.Ngonge, E.D., Hollanda, M.H.B.M., Nsifa, E.N., Tchoua, F.M.Petrology of the Guenfalabo ring complex: an example of a complete series along the Cameroon Volcanic Line ( CVL) Cameroon.Journal of African Earth Sciences, Vol. 96, pp. 139-154.Africa, CameroonAlkalic
DS201703-0396
2017
Hollanda, M.H.B.M.Almeida, V.V., Janasi, V.A., Heaman, L.M., Shaulis, B.J., Hollanda, M.H.B.M., Renne, P.R.Contemporaneous alkaline and tholeiitic magmatism in the Ponta Grossa Arch, Parana Etendeka magmatic province: constraints from U-Pb zircon baddeleyite and 40Ar/39Ar phlogopite dating of the Jose Fernandes gabbro and mafic dykes.Journal of Volcanology and Geothermal Research, in press available 11p.South America, BrazilAlkaline rocks

Abstract: We report the first high-precision ID-TIMS U-Pb baddeleyite/zircon and 40Ar/39Ar step-heating phlogopite age data for diabase and lamprophyre dykes and a mafic intrusion (José Fernandes Gabbro) located within the Ponta Grossa Arch, Brazil, in order to constrain the temporal evolution between Early Cretaceous tholeiitic and alkaline magmatism of the Paraná-Etendeka Magmatic Province. U-Pb dates from chemically abraded zircon data yielded the best estimate for the emplacement ages of a high Ti-P-Sr basaltic dyke (133.9 ± 0.2 Ma), a dyke with basaltic andesite composition (133.4 ± 0.2 Ma) and the José Fernandes Gabbro (134.5 ± 0.1 Ma). A 40Ar/39Ar phlogopite step-heating age of 133.7 ± 0.1 Ma from a lamprophyre dyke is identical within error to the U-Pb age of the diabase dykes, indicating that tholeiitic and alkaline magmatism were coeval in the Ponta Grossa Arch. Although nearly all analysed fractions are concordant and show low analytical uncertainties (± 0.3-0.9 Ma for baddeleyite; 0.1-0.4 Ma for zircon; 2s), Pb loss is observed in all baddeleyite fractions and in some initial zircon fractions not submitted to the most extreme chemical abrasion treatment. The resulting age spread may reflect intense and continued magmatic activity in the Ponta Grossa Arch.
DS1986-0533
1986
Hollander, M.Mathez, E.A., Blacic, J.D., Beery, J., Maggiore, C., Hollander, M.Carbon in olivine by nuclear reaction analysisProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 273-275GlobalBlank
DS1987-0444
1987
Hollander, M.Mathez, E.A., Blacic, J.D., Beery, J., Hollander, M., Maggiore, C.Carbon in olivine: results from nuclear reaction analysisJournal of Geophys., Res, Vol. 92, No. B5, April 10, pp. 3500-3506GlobalMantle genesis
DS1984-0492
1984
Hollander.Mathez, E.A., Blacic, J.D., Beery, J., Maggiore, C., Hollander.Carbon Abundances in Mantle Minerals Determined by Nuclear Reaction Analysis.Geophysical Research. LETTERS, Vol. 11, No. 10, OCTOBER, PP. 947-950.United States, Colorado Plateau, New MexicoXenolith, Crystallography
DS1993-0689
1993
Hollaway, J.Hollaway, J.Review of technology for the successful development of small scale miningChamber of Mines Journal (Zimbabwe), March pp. 19-25.Zimbabwe, AfricaMineral processing -small scale mining, Not specific to diamonds
DS200612-0597
2006
Hollaway, J.Hollaway, J.Katanga: mineral wealth, human challenges. The mineral wealth of the Congo is a phrase much used nowadays, often in condemnation of those endeavouring to developLondon Mining Journal, March 31, p. 24-25.Africa, Democratic Republic of CongoHistory, mineralogy - not specific to diamonds
DS200712-0448
2006
Hollaway, J.Hollaway, J.Saving Africa. The third in the trilogy 1) All poor together and 2) A great deal of nonsence.... Capricorn books approx 15 lbs.word-power.co.uk, AfricaBook - culture, social responsibility
DS1995-0816
1995
Hollbrook, S.Hollbrook, S.Magmatism: underplating over hotspotsNature, Vol. 373, No. 6515, Feb. 16, p. 559.MantleHotspots, Subduction
DS1995-0817
1995
Hollbrook, W.S.Hollbrook, W.S.Magmatism: underplating over hotspotsNature, Vol. 373, No. 6515, Feb. 16, p. 559MantleHotspots, Subduction
DS201906-1302
2019
Holler, J.Holler, J.Teaching critical open GIS.The Canadian Geographer, doi.org/10.1111/ cag.12521GlobalGIS

Abstract: Higher-education geographic information system (GIS) curricula largely marginalize and separate instruction of critical GIS and open GIS, paralleling a divide between GIS and non-GIS in geography. GIS is typically represented as a singular, infallibly objective, and universally applicable technology. GIS generally dismisses the critiques from human geography, while critical human geography dismisses GIS for its association with positivism and unethical applications. Teaching critical open GIS may bridge this divide, creating a transformative pedagogical space for human geography to affectively and effectively engage with open GIS technology at the level of code. Critical open GIS students practice and critique GIS as conflicted insiders, bridging the divide between GIS and non-GIS in their geography education. Reviews of GIS curricula find support for teaching critical and open GIS, but reviews of texts and syllabi confirm their marginalization and separation. A new critical open GIS course is introduced, using GIS in development and political ecology as integrative frameworks.
DS1993-0690
1993
Hollerbach, R.Hollerbach, R., Jones, C.A.Influence of the earth's inner core on geomagnetic fluctuations andreversalsNature, Vol. 365, No. 6446, October 7, pp. 541-543MantleGeophysics, Crust-core, Geomagnetics
DS201604-0636
2016
Hollick, L.Thomas, R.J, Spencer, C., Bushi, A.M., Baglow, N., Gerrit de Kock, B., Hortswood, M.S.A., Hollick, L., Jacobs, J., Kajara, S., Kaminhanda, G., Key, R.M., Magana, Z., McCourt, M.W., Momburi, P., Moses, F., Mruma, A., Myamilwa, Y., Roberts, N.M.W., HamisiGeochronology of the centra Tanzania craton and its southern and eastern orogenic margins.Precambrian Research, in press available 57p.Africa, TanzaniaGeochronology

Abstract: Geological mapping and zircon U-Pb/Hf isotope data from 35 samples from the central Tanzania Craton and surrounding orogenic belts to the south and east allow a revised model of Precambrian crustal evolution of this part of East Africa. The geochronology of two studied segments of the craton shows them to be essentially the same, suggesting that they form a contiguous crustal section dominated by granitoid plutons. The oldest orthogneisses are dated at ca. 2820 Ma (Dodoma Suite) and the youngest alkaline syenite plutons at ca. 2610 Ma (Singida Suite). Plutonism was interrupted by a period of deposition of volcano-sedimentary rocks metamorphosed to greenschist facies, directly dated by a pyroclastic metavolcanic rock which gave an age of ca. 2725 Ma. This is supported by detrital zircons from psammitic metasedimentary rocks, which indicate a maximum depositional age of ca. 2740 Ma, with additional detrital sources 2820 and 2940 Ma. Thus, 200 Ma of episodic magmatism in this part of the Tanzania Craton was punctuated by a period of uplift, exhumation, erosion and clastic sedimentation/volcanism, followed by burial and renewed granitic to syenitic magmatism. In eastern Tanzania (Handeni block), in the heart of the East African Orogen, all the dated orthogneisses and charnockites (apart from those of the overthrust Neoproterozoic granulite nappes), have Neoarchaean protolith ages within a narrow range between 2710 and 2630 Ma, identical to (but more restricted than) the ages of the Singida Suite. They show evidence of Ediacaran "Pan-African" isotopic disturbance, but this is poorly defined. In contrast, granulite samples from the Wami Complex nappe were dated at ca. 605 and ca. 675 Ma, coeval with previous dates of the "Eastern Granulites" of eastern Tanzania and granulite nappes of adjacent NE Mozambique. To the south of the Tanzania Craton, samples of orthogneiss from the northern part of the Lupa area were dated at ca. 2730 Ma and clearly belong to the Tanzania Craton. However, granitoid samples from the southern part of the Lupa "block" have Palaeoproterozoic (Ubendian) intrusive ages of ca. 1920 Ma. Outcrops further south, at the northern tip of Lake Malawi, mark the SE continuation of the Ubendian belt, albeit with slightly younger ages of igneous rocks (ca. 1870-1900 Ma) which provide a link with the Ponte Messuli Complex, along strike to the SE in northern Mozambique. In SW Tanzania, rocks from the Mgazini area gave Ubendian protolith ages of ca. 1980-1800 Ma, but these rocks underwent Late Mesoproterozoic high-grade metamorphism between 1015 and 1040 Ma. One granitoid gave a crystallisation age of ca. 1080 Ma correlating with known Mesoproterozoic crust to the east in SE Tanzania and NE Mozambique. However, while the crust in the Mgazini area was clearly one of original Ubendian age, reworked and intruded by granitoids at ca. 1 Ga, the crust of SE Tanzania is a mixed Mesoproterozoic terrane and a continuation from NE Mozambique. Hence the Mgazini area lies at the edge of the Ubendian belt which was re-worked during the Mesoproterozoic orogen (South Irumide belt), providing a further constraint on the distribution of ca. 1 Ga crust in SE Africa. Hf data from near-concordant analyses of detrital zircons from a sample from the Tanzania Craton lie along a Pb-loss trajectory (Lu/Hf = 0), extending back to ~3.9 Ga. This probably represents the initial depleted mantle extraction event of the cratonic core. Furthermore, the Hf data from all igneous samples, regardless of age, from the entire study area (including the Neoproterozoic granulite nappes) show a shallow evolution trend (Lu/Hf = 0.028) extending back to the same mantle extraction age. This implies the entire Tanzanian crust sampled in this study represents over 3.5 billion years of crustal reworking from a single crustal reservoir and that the innermost core of the Tanzanian Craton that was subsequently reworked was composed of a very depleted, mafic source with a very high Lu/Hf ratio. Our study helps to define the architecture of the Tanzanian Craton and its evolution from a single age-source in the early Eoarchaean.
DS1996-0643
1996
Hollick, P.Hollick, P., Gurney, J.Namaqualand and Namibian off shore diamond distributionProspectors and Developers Association of Canada (PDAC) Short Course, pp. 219-238NamibiaGeostatistics, statistics, diamond, Short course -Exploration technology
DS1996-0644
1996
Hollick, P.Hollick, P., Gurney, J.Namaqualand and Namibian off shore diamond distribution, a wave refractioncontrol.Prospectors and Developers Association of Canada (PDAC) Short Course, 96, pp. 219-238.Namibia, South AfricaAlluvials, Marine, Mining techniques
DS1995-2073
1995
Hollick, P.C.Woodborne, M.W., De Decker, R.H., Hollick, P.C., Gurney, J.New information on wave cut terraces and the importance in relation To diamond deposits on west coast South AfricaExploration and Mining Geology, Vol. 4, No. 1, p. 91.South AfricaMarine mining, Terraces
DS1998-0633
1998
Hollick, P.C.Hollick, P.C., Gurney, J.J.Contrasting styles of marine diamond mineralization requiring different mining methodologies - case study29th. Annual Underwater Mining Institute, 1p. abstractSouth AfricaMarine mining
DS1994-0784
1994
Holliger, K.Holliger, K., Levander, A.Lower crustal reflectivity modeled by rheological controls on maficintrusionsGeology, Vol. 22, No. 4, April pp. 367-370Basin and RangeLithosphere, Phanerozoic
DS1992-0719
1992
Hollings, L.Hollings, L.Australia: world player or regional backwater?Australian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 4, July pp. 49-52AustraliaEconomics, Mining industry
DS1998-1603
1998
Hollings, P.Wyman, D., Hollings, P.Long lived mantle plume influence on an Archean protocontinent: geochemical evidence greenstone beltGeology, Vol. 26, No. 8, Aug. pp. 719-722OntarioLumby Lake greenstone belt, Komatiite, tholeiite, craton
DS1999-0314
1999
Hollings, P.Hollings, P., Wyman, D.Trace element and Sm neodymium systematics of volcanic and intrusive rocks from 3Ga Lumby Lake Greenstone belt..Lithos, Vol. 46, pp. 189-213.OntarioPlume Arc interaction, Geochronology - regional not specific to diamonds
DS2000-0418
2000
Hollings, P.Hollings, P., Kerrich, R.An Archean arc basalt niobium enriched basalt adakite association: the 2.7 Ga Confederation assemblage...Contributions to Mineralogy and Petrology, Vol. 139, No. 2, pp. 208-26.OntarioSuperior Province, Adakite
DS2002-0732
2002
Hollings, P.Hollings, P., Ansdell, K.Paleoproterozoic arc magmatism imposed on older backarc basin: implications for the tectonic evolution of ...Geological Society of America Bulletin, Vol. 114, 2, pp. 153-68.Alberta, Saskatchewan, ManitobaTrans Hudson Orogen, Magmatism
DS200612-1551
2005
Hollings, P.Wyman, D.A., Hollings, P.Late Archean convergent margin volcanism in the Superior Province: a comparison of the Blake River Group and Confederation assemblage.Benn, K., Mareschal, J-C., Condie, K.C. Archean Geodynamics and Environments, AGU Geophysical Monograph, No. 164, pp. 215-238.Canada, Ontario, Superior ProvinceVolcanism - not specific to diamonds
DS201507-0341
2015
Hollings, P.Wyman, D.A., Hollings, P., Conceicao, R.V.Geochemistry and radiogenic isotope characteristics of xenoliths in Archean Diamondiferous lamprophyres: implications for the Superior Province cratonic keel.Lithos, Vol. 233, pp. 111-130.Canada, OntarioLamprophyre
DS1960-0841
1967
Hollingsworth, J.S.Hollingsworth, J.S.Geology of the Wilson Springs Vanadium DepositsArkansaw GEOL. COMM. CENTRAL Arkansaw ECONOMIC GEOLOGY AND P, PP. 22-24.United States, Gulf Coast, Arkansas, Garland CountyVanadium, Potash Sulfur Springs Complex
DS1980-0176
1980
Hollis, J.Hollis, J.Diamond - Carbon's CinderellaAustralian Natural History, Vol. 20, No. 3, PP. 83-86.GlobalGenesis, History
DS201610-1884
2016
Hollis, J.Lindsay, M., Spratt, J., Occhipinti, S., Aitken, A., Dentith, M., Metelka, V., Hollis, J., Tyler, I.Integrated interpretation of magnetotelluric and potential field data: assessing the northeast Kimberley region. ( no mention of kimberlites)ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 4p.AustraliaGeophysics
DS202002-0187
2020
Hollis, J.A.Gardiner, N.J., Kirkland, C.L., Hollis, J.A., Cawood, P.A., Nebel, O., Szilas, K., Yakymchuk, C.North Atlantic craton architecture revealed by kimberlite-hosted crustal zircons.Earth and Planetary Science Letters, Vol. 534, 8p. PdfEurope, Greenlandkimberlite genesis

Abstract: Archean cratons are composites of terranes formed at different times, juxtaposed during craton assembly. Cratons are underpinned by a deep lithospheric root, and models for the development of this cratonic lithosphere include both vertical and horizontal accretion. How different Archean terranes at the surface are reflected vertically within the lithosphere, which might inform on modes of formation, is poorly constrained. Kimberlites, which originate from significant depths within the upper mantle, sample cratonic interiors. The North Atlantic Craton, West Greenland, comprises Eoarchean and Mesoarchean gneiss terranes - the latter including the Akia Terrane - assembled during the late Archean. We report U-Pb and Hf isotopic, and trace element, data measured in zircon xenocrysts from a Neoproterozoic (557 Ma) kimberlite which intruded the Mesoarchean Akia Terrane. The zircon trace element profiles suggest they crystallized from evolved magmas, and their Eo-to Neoarchean U-Pb ages match the surrounding gneiss terranes, and highlight that magmatism was episodic. Zircon Hf isotope values lie within two crustal evolution trends: a Mesoarchean trend and an Eoarchean trend. The Eoarchean trend is anchored on 3.8 Ga orthogneiss, and includes 3.6-3.5 Ga, 2.7 and 2.5-2.4 Ga aged zircons. The Mesoarchean Akia Terrane may have been built upon mafic crust, in which case all zircons whose Hf isotopes lie within the Eoarchean trend were derived from the surrounding Eoarchean gneiss terranes, emplaced under the Akia Terrane after ca. 2.97 or 2.7 Ga, perhaps during late Archean terrane assembly. Kimberlite-hosted peridotite rhenium depletion model ages suggest a late Archean stabilization for the lithospheric mantle. The zircon data support a model of lithospheric growth via tectonic stacking for the North Atlantic Craton.
DS1982-0590
1982
Hollis, J.D.Sutherland, F.L., Hollis, J.D., Barron, L.M.Garnet Lherzolite and Other Inclusions from a Basalt Flow Bow Hill, Tasmania.Proceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 221, (abstract.).GlobalKimberlite
DS1983-0628
1983
Hollis, J.D.Wass, S.Y., Hollis, J.D.Crustal Growth in South Eastern Australia- Evidence from Lower Crustal Eclogite and Granulite Xenoliths.Journal of METAMORPHIC PETROL., Vol. 1, PP. 25-45.Australia, South EasternAnakies, Basalt, Related Rocks, Geochemistry
DS1984-0318
1984
Hollis, J.D.Griffin, W.L., Wass, S.Y., Hollis, J.D.Ultramafic Xenoliths from Bulletinenmerri and Gnotuk Maars, Victoria, Australia: Petrology of a Sub-continental Crust-mantle Transition.Journal of PETROLOGY, Vol. 25, PT. 1, PP. 53-87.Australia, VictoriaBasanite, Wehrlites, Spinel Lherzolites
DS1984-0717
1984
Hollis, J.D.Sutherland, F.L., Hollis, J.D., Barron, L.M.Garnet Lherzolite and Other Inclusions from a Basalt Flow, Bow Hill, Tasmania.Proceedings of Third International Kimberlite Conference, Vol. 2, PP. 145-160.Australia, TasmaniaHawaiite, Petrology, Major Element Analyses, Garnet
DS1984-0726
1984
Hollis, J.D.Temby, P.A., Sutherland, F.L., Hollis, J.D.Distribution and Origin of Diamonds in Eastern AustraliaGeological Society of Australia ABSTRACT VOLUME., No. 12, PP. 516-517.Australia, Eastern AustraliaCopeton, Origin
DS1986-0791
1986
Hollis, J.D.Sutherland, F.L., Hollis, J.D., Raynor, L.R.Diamonds from nepheline mugearite- a discussion of garnet web sterites and associated ultramafic inclusions from nepheline mugearite in the Malcha area New South WalesAustMineralogical Magazine, Vol. 49, No. 354, December pp. 748-751Australia, New South WalesInclusions
DS1986-0792
1986
Hollis, J.D.Sutherland, F.L., Raynor, L.R., Hollis, J.D., Temby, P.A.Prospective relationships between diamonds, volcanism and tectonisMProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 484-486AustraliaDiamond exploration, New South Wales
DS1987-0258
1987
Hollis, J.D.Griffin, W.L., Sutherland, F.L., Hollis, J.D.Correlation of xenolith petrology and seismic data; an example from east central QueenslandUnited States Geological Survey (USGS) Circ.No. 956 Geophysics and petrology of the deep crust and upper, pp. 30-31AustraliaXenoliths
DS1991-1678
1991
Hollis, J.D.Sutherland, F.L., Temby, P., Hollis, J.D., Raynor, L.R.Anomalous hosts, unusual characters and the role of hot and cool geothermsfor east Australian diamond sourcesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 398-400AustraliaBasalts, Copeton, Bingara, Walcha, Airly Mt, Diamond morphology
DS1992-1500
1992
Hollis, J.D.Sutherland, F.L., Hollis, J.D., Brich, W.D.Xenolith samples of a young mantle crust magma chamber, related to the Newer basalts of western VIC and relevant to the southeast Australia geotherm.11th. Australian Geol. Convention Held Ballarat University College, Jan., Listing of papers to be given attempting to get volAustraliaMantle, Xenoliths
DS1994-1723
1994
Hollis, J.D.Sutherland, F.L., Temby, P., Raynor, L.R., Hollis, J.D.A review of the east Australian diamond provinceProceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 170-186.AustraliaDiamond, Review
DS2001-0485
2001
Hollis, J.D.Hollis, J.D.Distribution and origins of heavy minerals in post Paleozoic alkaline volcanics of west central Victoria, Australia.Proceedings of the Royal Society of New South Wales, Vol. 134, 3-4, pp. 108-9.AustraliaGeochemistry
DS2003-0596
2003
Hollis, J.D.Hollis, J.D.Morphology of diamond crystals from the Bingara Range, northern New South WalesAustralian Gemmologist, Vol. 21, 9, pp. 350-359.Australia, New South WalesDeposit - Bingara
DS200412-0844
2003
Hollis, J.D.Hollis, J.D.Morphology of diamond crystals from the Bingara Range, northern New South Wales, Australia.Australian Gemmologist, Vol. 21, 9, pp. 350-359. (310-319).Australia, New South WalesDiamond - morphology Deposit - Bingara
DS200412-1952
2004
Hollis, J.D.Sutherland, F.L., Hollis, J.D., Birch, W.D., Fogson, R.E., Raynor, L.R.Cumulate rich xenolith suite in Late Cenozoic basaltic eruptives Hepburn Lagoon, Newlyn in relation to western Victorian lithospAustralian Journal of Earth Sciences, Vol. 51, 3, June pp. 319-338.AustraliaXenoliths
DS200512-1066
2004
Hollis, J.D.Sutherland, F.L., Hollis, J.D., Birch, W.D., Pogson, R.E., Raynor, L.R.Cumulate rich xenolith suite in Late Cenozoic basaltic eruptives, Hepburn Lagoon, Newlyn in relation to western Victorian lithosphere.Australian Journal of Earth Sciences, Vol. 51, 3, pp. 319-337.Australia, VictoriaXenoliths
DS2003-0412
2003
Hollis, M.A.Flemming, R.L., Hollis, M.A.X-ray microdiffraction as a potential tool for diamond exploration: dat a from kimberliteGeological Association of Canada Annual Meeting, Abstract onlyGlobalTechniues - microdiffraction
DS200412-0560
2003
Hollis, M.A.Flemming, R.L., Hollis, M.A.X-ray microdiffraction as a potential tool for diamond exploration: dat a from kimberlite indicator garnets.Geological Association of Canada Annual Meeting, Abstract onlyTechnologyTechniues - microdiffraction
DS1993-0691
1993
Hollister, L.S.Hollister, L.S.The role of melt in the uplift and exhumation of orogenic beltsChemical Geology, Vol. 108, No. 1-4, August 5, pp. 31-48MantleMelt, Tectonics
DS1994-0379
1994
Hollister, L.S.Davidson, C., Schmid, S.M., Hollister, L.S.Role of melt during deformation in the deep crustTerra Nova, Vol. 6, No. 2, pp. 133-142.GlobalMelting, Subduction
DS1998-0634
1998
Hollnack, D.Hollnack, D., Stangl, R.The seismicity related to the southern part of the Kenya RiftJournal of African Earth Sciences, Vol. 26, No. 3, Apr. pp. 477-95.KenyaGeophysics - seismics, Tectonics
DS200712-0449
2006
Holloway, G.Holloway, G.Diamond grading laboratory peer review.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.159. abstract onlyTechnologyDiamond grading
DS200912-0309
2009
Holloway, G.Holloway, G.Blue fluoresence in diamonds.Australian Gemmologist, Vol. 23, 9, 1p.TechnologyDiamond colour
DS201511-1881
2014
Holloway, G.Sivovolenko, S., Shelementiev, Y., Holloway, G., Mistry, J., Serov, R., Zhulin, S., Zipa, K.How diamond performance attritbutes: brilliance, scintillation and fire depend on human vision features.Australian Gemmologist, Vol. 25, 3, July-Sept. pp.TechnologyDiamond features

Abstract: This study describes how visual properties determine the perception of a diamond’s appearance and its performance attributes of brilliance, scintillation and fire, and how these influence beauty. Further articles will describe other parts of our cut study project. This research enables the development of methods and instruments for diamond performance analyses, shifting from current diamond cut rejection based tools, to diamond performance scoring systems, and the introduction of a new consumer language for communication between diamond buyers and sellers. The proposed Performance Scoring System is consumer friendly and can be used to design and manufacture new diamond cuts with improved optical appearance.
DS201810-2327
2018
Holloway, G.Holloway, G.What size does that diamond look like? Carat weight patent pending "Looks Like Size".The Australian Gemmologist, Vol. 26, 9-10, pp. 240-248.Globaldiamond morphology
DS1988-0311
1988
Holloway, H.Holloway, H.A site percolation threshold for the diamond lattice withdiatomicsubstitutionPhysics Rev. B., Vol. 37, No. 2, January 15, pp. 874-877GlobalBlank
DS1992-0720
1992
Holloway, J.Holloway, J.Options for mining developments in AfricaNatural Resources forum, Vol. 16, No. 2, May pp. 154-157AfricaEconomics, Mining plans
DS1993-0692
1993
Holloway, J.Holloway, J.Review of technology for the successful development of small scale miningChamber of Mines Journal, (Zimbabwe), March pp. 19-25ZimbabweMining, Small scale mining parameters
DS1996-0645
1996
Holloway, J.Holloway, J.Environmental problems in Zimbabwe from gold panningCrs Perspectives, No. 52, Jan. pp. 25-28ZimbabweEconomics -gold, Mining -small scale
DS1997-0515
1997
Holloway, J.Holloway, J.Successful mining in Africa: the rulesMiga Conference Held June 3-5, Denver, 11pAfricaEconomics, discoveries, Legal, environmental
DS1984-0266
1984
Holloway, J.R.Esperanca, S., Holloway, J.R.Lower Crustal Nodules from the Camp Creek Latite, Carefree Arizona.Proceedings of Third International Kimberlite Conference, Vol. 2, PP. 219-227.United States, Arizona, Colorado PlateauPetrography, Mineralogy, Microprobe, Analyses, Geothermometry
DS1985-0178
1985
Holloway, J.R.Esperanca, S., Holloway, J.R.An Experimental Study of Mafic Minette from Buell Park, Arizona.Geological Association of Canada (GAC)., Vol. 10, P. A17. (abstract.).United States, Arizona, Colorado PlateauMineral Chemistry
DS1987-0190
1987
Holloway, J.R.Esperanca, S., Holloway, J.R.On the origin of some mica lamprophyres: experimental evidence from a maficminetteContributions to Mineralogy and Petrology, Vol. 95, pp. 207-216ArizonaBuell Park, Minette
DS1990-0196
1990
Holloway, J.R.Bertka, C.M., Holloway, J.R., Mysen, B.O.Partial melting phase relations in an iron-rich mantleCarnegie Institution Geophysical Laboratory Annual Report of the Director, No. 2200, pp. 80-87GlobalExperimental petrology, Lherzolite/mantle
DS1993-1200
1993
Holloway, J.R.Pawley, A.R., Holloway, J.R.Water sources for subduction zone volcanism: new experimental constraintsScience, Vol. 260, April 30, pp. 664-667GlobalSubduction,, Mantle, Tectonics
DS1993-1609
1993
Holloway, J.R.Tourette, T.Z., Holloway, J.R.Experimental measurement of the graphite/diamond (C, O) fluid equilibrium at80 Kb.American Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 636.GlobalExperimental petrology, Graphite/diamond
DS1994-0988
1994
Holloway, J.R.LaTourette, T., Holloway, J.R.Oxygen fugacity of the diamond + C-O fluid assemblage and CO2 fugacity at 8GPa.Earth Planetary Science Letters, Vol. 128, No. 3-4, Dec. pp. 439-452.GlobalDiamond genesis
DS1994-1759
1994
Holloway, J.R.Thibault, Y., Holloway, J.R.Solubility of CO2 in a Calcium rich leucitite: effects of pressure, temperature and oxygen fugacity.Contributions to Mineralogy and Petrology, Vol. 116, pp. 216-224.GermanyLeucitite, West Eifel
DS1996-0246
1996
Holloway, J.R.Carroll, M.R., Holloway, J.R.Volatiles in magmasReviews in Mineralogy, Vol. 30, approx. 40.00 United StatesGlobalBook - Table of contents, Magmas - volatiles, geochemistry, melts, volcanic gas, noble gases
DS1996-0372
1996
Holloway, J.R.Domanik, K.J., Holloway, J.R.The stability and composition of phengitic muscovite and associated phases from 5.5 to 11 GPa: subductionGeochimica et Cosmochimica Acta, Vol. 60, No. 21, pp. 4133-50.GlobalEclogites, subduction zones, Petrology - experimental
DS1996-0719
1996
Holloway, J.R.Kawamoto, T., Hervig, R.L., Holloway, J.R.Experimental evidence for a hydrous transition zone in the earth's mantleEarth and Planetary Science Letters, Vol. 142, No. 3/4, Aug. 1, pp. 587-592.MantlePetrology -experimental, Hydrous transition zone
DS1997-0131
1997
Holloway, J.R.Brooker, R., Holloway, J.R.The role of CO2 saturation in silicate carbonatite magmatic systemsGeological Association of Canada (GAC) Abstracts, GlobalCarbonatite
DS1998-0635
1998
Holloway, J.R.Holloway, J.R.Graphite melt equilibration temperatures during mantle melting: constraints on CO2 in Mid Ocean Ridge Basalt (Mid Ocean Ridge Basalt (MORB))magmas and carbon content..Chemical Geology, Vol. 147, No. 1-2, May 15, pp. 89-98.MantleGraphite, carbon, Magmatism
DS2003-0794
2003
Holloway, J.R.Lensky, N.G., Niebo, R.W., Holloway, J.R., Lyakhovsky, V., Navon, O.Bubble nucleation as a trigger for xenolith entrapment in mantle melts8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractGlobalKimberlite geology and economics
DS200612-0800
2006
Holloway, J.R.Lensky, N.G., Nicho, R.W., Holloway, J.R., Lyakhovsky, V., Navon, O.Bubble nucleation as a trigger for xenolith entrapment in mantle melts.Earth and Planetary Science Letters, Vol. 245, 1-2, pp. 278-288.MantleMelting
DS200812-0514
2008
Holloway, J.R.Jakobsson, S., Holloway, J.R.Mantle melting in equilibrium with an iron wustite.. graphite buffered COH fluid.Contributions to Mineralogy and Petrology, Vol. 155, 2, pp. 247-256.MantleMelting
DS1995-0633
1995
HolmGill, R.C.O., Holm, NielsenWas a short lived Baffin Bay plume active prior to initiation of present Icelandic plume? clues from high magnesium picrites of west Greenland.L.Lithos, Vol. 34, pp. 27-39.GlobalMantle - plumes, Picrites
DS1998-0636
1998
Holm, D.Holm, D., Schneider, D., Coath, C.D.Age and deformation of Early Proterozoic quartzites in the southern Lake superior region: implications for ..Geology, Vol. 26, No. 10, Oct. pp. 907-10Wisconsin, MichiganTectonics, Laurentia Mazatzal orogeny
DS2002-0733
2002
Holm, D.Holm, D., Schneider, D.40 Ar 39 Ar evidence for ca 1800 Ma tectonothermal activity along the Great Falls tectonic zone, central Montana.Canadian Journal of Earth Sciences, Vol. 39, 12, Dec. pp. 1719-28.MontanaGeochronology
DS2002-0734
2002
Holm, D.J.Holm, D.J., Schneider, D.40 Ar 39 Ar evidence for ca 1800 Ma tectonothermal activity along the Great Falls tectonic zone, central Montana.Canadian Journal of Earth Sciences, Vol. 39, 12, pp. 1719-28.MontanaTectonics, Geothermometry, geochronology
DS1993-0693
1993
Holm, D.K.Holm, D.K., Holst, T.B., Lux, D.R.Post collisional cooling of the Penokean orogen in east-central MinnesotaCanadian Journal of Earth Sciences, Vol. 30, No. 5, May pp. 913-917MinnesotaTectonics, Geochronology
DS1997-0516
1997
Holm, D.K.Holm, D.K., Dahl, P.S.40Ar 39Ar evidence for Middle Proterozoic (1300-1500 Ma) slow cooling of southern Black Hills, midcontinentTectonics, Vol. 16, No. 4, August pp. 609-622.GlobalMagmatism, Tectonics
DS1998-0637
1998
Holm, D.K.Holm, D.K., Darrah, K.S., Lux, D.R.Evidence for Wide spread ~1760 Ma metamorphism and rapid crustal stabilization of Early Proterozoic Penokean...American Journal of Science, Vol. 298, Jan. pp. 60-81.MinnesotaOrogeny - Penokean, metamorphism
DS2003-0690
2003
Holm, D.K.Karlstrom, K.E., Sears, J.W., Holm, D.K., Williams, M.L., Wooden, HatcherSouthern Laurentia in Rodinia: collaborative compilation of a tectonic map for IGCPGeological Society of America, Annual Meeting Nov. 2-5, Abstracts p.342.RodiniaTectonics
DS200412-0954
2003
Holm, D.K.Karlstrom, K.E., Sears, J.W., Holm, D.K., Williams, M.L., Wooden, Hatcher, Finn, Price, Miller, BerquistSouthern Laurentia in Rodinia: collaborative compilation of a tectonic map for IGCP 440.Geological Society of America, Annual Meeting Nov. 2-5, Abstracts p.342.Gondwana, RodiniaTectonics
DS200712-0212
2007
Holm, D.K.Dahl, P.S., Hamilton, M.A., Wooden, J.L., Foland, K.A., Frei, R., McCombc, J.A., Holm, D.K.2480 Ma mafic magmatism in the northern Black Hills, South Dakota: a new link connecting the Wyoming and Superior Cratons.Canadian Journal of Earth Sciences, Vol. 43, 10, pp. 1579-1600.United States, Wyoming, Canada, AlbertaMagmatism
DS1990-0714
1990
Holm, P.E.Holm, P.E.Complex petrogenetic modeling using spreadsheet softwareComputers and Geosciences, Vol. 16, No. 8, pp. 1117-1122GlobalComputer, Program -petrogenesis
DS1983-0519
1983
Holm, P.M.Platt, R.G., Mitchell, R.H., Holm, P.M.Marathon Dikes: Rubidium-strontium and Potassium-argon Geochronology of ultrabasic Lamprophyres from the Vicinity of Mckellar Harbour, Northwestern ontario, Canada.Canadian Journal of Earth Sciences, Vol. 20, No. 6, PP. 961-967.GlobalRelated Rocks, Melilite
DS1986-0369
1986
Holm, P.M.Holm, P.M., Konnerup-Madsen, J.Characteristics of mafic potassium-rich rocks from central Italian lamproite and their petrogenesis. *DAN.In: 17th. Nordic Geol. Meeting, abstracts, Noriska Geologmotet, p. 55. abstractItalyLamproite
DS1992-0721
1992
Holm, P.M.Holm, P.M., Gill, R.C.O., Pedersen, A.K., Larsen, J.G., Hald, N.The Icelandic mantle plume: compositional constraints from the West Greenland Tertiary picritesEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.336GreenlandPicrites, Mantle plume
DS1993-0694
1993
Holm, P.M.Holm, P.M., Gill, R.C.O., Pedersen, A.K., Larsen, J.G., Hald, N.The Tertiary picrites of West Greenland: contributions from Icelandic and other sourcesEarth and Planetary Science Letters, Vol. 115, No. 1-4, March pp. 227-244GreenlandPicrites, Alkaline rocks
DS1995-0634
1995
Holm, P.M.Gill, R.C.O., Holm, P.M., Nielsen, T.F.D.Was a short lived Baffin Bay plume active prior to initiation of the present Icelandic plume? Clues ..Lithos, Vol. 34, No. 1-3, Jan. pp. 27-40GreenlandPicrite -magnesiuM., Plume
DS1996-0646
1996
Holm, P.M.Holm, P.M., Praegel, N.O., Brooks, C.K., Nielsen, T.F.D.Lithosphere derived basaltic and lamprophyric low - from the Tertiary east Greenland rifted margin.International Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 356.GreenlandLamprophyres
DS1996-1092
1996
Holm, P.M.Pedersen, L.E., Holm, P.M., Hoisteen, B.Plume related magmatism on the margin of the Baltic shields: geochemistry and isotopic signatures -dykesInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 356.GlobalGeochemistry, Proterozoic dyke swarm
DS2001-0552
2001
Holm, P.M.Jorgensen, J.O., Holm, P.M.The role of carbonatites in the Cape Verde magmatism: lead, Strontium, and neodymium isotopic evidence of multiple sourcesJournal of South African Earth Sciences, Vol. 32, No. 1, p. A 20 (abs)GlobalCarbonatite, Geochronology
DS2001-0553
2001
Holm, P.M.Jorgensen, J.O., Holm, P.M.A geochemical comparison of magnesiocarbonatites and co-existing suite of ocean island basalts ...Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 20 (abs)GlobalCarbonatite, Sao Vicente Island
DS201412-0035
2014
Holm, P.M.Barker, A.K., Holm, P.M., Troll, V.R.The role of eclogite in the mantle heterogeneity at Cape Verde.Contributions to Mineralogy and Petrology, Vol. 168, pp. 1052-1058.MantleEclogite
DS1994-1931
1994
Holm, R.F.Wittke, J.H., Holm, R.F.Phaneritic feldspathoidal rocks from House Mountain volcano, CentralArizona: product of liquid immisicibility?Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p. posterArizonaAlkaline rocks, House Mountain
DS1996-1554
1996
Holm, R.F.Witke, J.H., Holm, R.F.The association basanitic nephelinite feldspar ijolite nephelinemonzo syenite at House Mountain volcano.Canadian Mineralogist, Vol. 34, pt. 2, April pp. 221-240.ArizonaBasanite, Ijolite
DS1989-0655
1989
Holm, R.G.Holm, R.G., Jackson, R.D., Yuan, B.Surface reflectance factor retrieval from thematic mapper dataRemote Sensing Environ, Vol. 27, pp. 47-57. Database # 17792GlobalRemote Sensing, TEM.
DS1991-0599
1991
Holman, P.B.Grasty, R.L., Holman, P.B., Blanchard, Y.B.Transportable calibration pads for ground and airborne gamma rayspectrometersGeological Survey of Canada Paper, No. 90-23, 25pCanadaSpectrometry, Program -PADWIN.
DS1994-0284
1994
Holman, P.B.Charbonneau, B.W., Holman, P.B., Hetu, R.J.Airborne geophysical survey, northeast AlbertaGeological Survey of Canada Open File, No. 2807, 13 maps $ 195.00AlbertaGeophysics
DS1993-0695
1993
Holmden, C.Holmden, C., Muelenbachs, K.The 18O/16O ratio of 2-Billion year old Seawater inferred from ancient oceanic crustScience, Vol. 259, March 19, pp. 1733-1735MantleCrust, Geochronology
DS2002-1549
2002
Holme, R.Steinberger, B., Holme, R.An explanation for the shape of Earth's gravity spectrum based on viscous mantle flow models.Geophysical Research Letters, Vol. 29, 21, Nov. 1, p. 15 DOI 10.1029/2002GLO015476MantleGeophysics - seismics
DS200812-1120
2008
Holme, R.Steinberger, B., Holme, R.Mantle flow models with core mantle boundary constraints and chemical heterogeneities.Journal of Geophysical Research, Vol. 113, B5, B05403.MantleGeophysics - seismics
DS201112-0443
2011
Holme, R.Holme, R., Olsen, N., Bairstow, F.L.Mapping geomagnetic secular variation at the core-mantle boundary.Geophysical Journal International, In press available,MantleGeophysics - magnetics
DS201212-0071
2012
Holme, R.Biggin, A.J., Steinberger, B., Aubert, J., Suttle, N., Holme, R., Torsvik, H., Van der Meer, D.G., Van Hinsbergen, J.J.Possible links between long term geomagnetic variations and whole mantle convection processes.Nature Geoscience, Vol. 5, pp. 526-533.MantleConvection
DS1930-0110
1932
Holmes, A.Holmes, A., Harwood, H.F.Petrology of the Volcanic Fields East and Southeast of Ruwenzori, Uganda.Quarterly Journal of Geological Society (London), Vol. 88, PP. 390-442.GlobalPetrology
DS1930-0218
1936
Holmes, A.Holmes, A.A Contribution to the Petrology of Kimberlite and its Inclusions.Sth. Afr. Geological Society Transactions, Vol. 39, PP. 379-428.South AfricaPetrology, Kimberlite, Genesis
DS1930-0219
1936
Holmes, A.Holmes, A., Paneeth, F.A.Helium Ratios of Rocks and Minerals from the Diamond Pipes Of South Africa.Royal Society. (London) Proceedings, Vol. 154A, No. 882, PP. 385-413.South AfricaPetrography
DS1930-0246
1937
Holmes, A.Holmes, A.Leucitised Granite Xenoliths from the Potassic Lavas of Bunyarugura Southwest Uganda.American Journal of Science, Vol. 248A, P. 313.GlobalLeucite, Crustal Xenoliths
DS1930-0247
1937
Holmes, A.Holmes, A.The Petrology of the Volcanic Area of BufumbiraGeological Society UGANDA., MEMOIR No. 3, PT. 2GlobalPetrology
DS1940-0097
1945
Holmes, A.Holmes, A.Leucitized Granite Xenoliths from the Potassic Lavas at Bunyarugura, Southwest Uganda.American Journal of Science, Vol. 243A, PP. 313-GlobalLeucite, Petrography, Crustal Xenoliths
DS1950-0278
1956
Holmes, A.Holmes, A.The Ejectamenta of Katui Crater, Southwest UgandaKon. Ned Mynb. Genootsch. Geol. Ser., Vol. 16, PP. 139-166.GlobalRelated Rocks
DS201904-0741
2019
Holmes, A.K.Grewal, D.S., Dasgupta, R., Holmes, A.K., Costin, G., Li, Y., Tsuno, K.The fate of nitrogen during core-mantle seperation on Earth.Geochimica et Cosmochimica Acta, Vol. 251. pp. 87-115.Mantlenitrogen

Abstract: Nitrogen, the most dominant constituent of Earth’s atmosphere, is critical for the habitability and existence of life on our planet. However, its distribution between Earth’s major reservoirs, which must be largely influenced by the accretion and differentiation processes during its formative years, is poorly known. Sequestration into the metallic core, along with volatility related loss pre- and post-accretion, could be a critical process that can explain the depletion of nitrogen in the Bulk Silicate Earth (BSE) relative to the primitive chondrites. However, the relative effect of different thermodynamic parameters on the alloy-silicate partitioning behavior of nitrogen is not well understood. Here we present equilibrium partitioning data of N between alloy and silicate melt () from 67 new high pressure (P?=?1-6?GPa)-temperature (T?=?1500-2200?°C) experiments under graphite saturated conditions at a wide range of oxygen fugacity (logfO2?~??IW -4.2 to -0.8), mafic to ultramafic silicate melt compositions (NBO/T?=?0.4 to 2.2), and varying chemical composition of the alloy melts (S and Si contents of 0-32.1?wt.% and 0-3.1?wt.%, respectively). Under relatively oxidizing conditions (~?IW -2.2 to -0.8) nitrogen acts as a siderophile element ( between 1.1 and 52), where decreases with decrease in fO2 and increase in T, and increases with increase in P and NBO/T. Under these conditions remains largely unaffected between S-free conditions and up to ~17?wt.% S content in the alloy melt, and then drops off at >~20?wt.% S content in the alloy melt. Under increasingly reduced conditions (<~?IW -2.2), N becomes increasingly lithophile ( between 0.003 and 0.5) with decreasing with decrease in fO2 and increase in T. At these conditions, fO2 along with Si content of the alloy under the most reduced conditions (<~?IW -3.0), is the controlling parameter with T playing a secondary role, while, P, NBO/T, and S content of the alloy have minimal effects. A multiple linear least-squares regression parametrization for based on the results of this study and previous studies suggests, in agreement with the experimental data, that fO2 (represented by Si content of the alloy melt and FeO content of the silicate melt), followed by T, has the strongest control on . Based on our modeling, to match the present-day BSE N content, impactors that brought N must have been moderately to highly oxidized. If N bearing impactors were reduced, and/or there was significant disequilibrium core formation, then the BSE would be too N-rich and another mechanism for N loss, such as atmospheric loss, would be required.
DS1950-0069
1951
Holmes, C.R.Holmes, C.R.Magnetic Fields Associated with Igneous Pipes in the Central Ozarks, Missouri.Engineering and Mining Journal, Vol. 187, No. 2, PP. 1143-1146.Missouri, United States, Central StatesKimberlite, Geophysics
DS1930-0248
1937
Holmes, F.M.Holmes, F.M.Miners and Their Works Underground. Stories of Mining of Coal, of Various Metals and of Diamonds.London: S.w. Partridge And Co., 160P.South AfricaKimberlite
DS1983-0311
1983
Holmes, G.Holmes, G., Shor, R.Signs of Confidence in the Diamond WorldJeweler's Circular Keystone., Jan., PP. 56-62.GlobalMarkets, Demand, Outlook
DS1984-0361
1984
Holmes, G.Holmes, G.Getting Ready for Australia's DiamondsJewellers Circular Keystone., Vol. CLV, No. 9, PT. 1, SEPTEMBER PP. 40-42.Australia, Western AustraliaArgyle, Mining, Photographs
DS1987-0297
1987
Holmes, G.Holmes, G.Brown is beautiful. Argyle diamond mine vistJewelers Circular Keystone, Vol. CLVIII, No. 7 July pp. 303-307AustraliaOverview, Argyle
DS1980-0222
1980
Holmes, G.G.Macnevin, A.A., Holmes, G.G.Gemstones; New South Wales Geological Survey, 1980New South Wales Geological Survey Mineral Industry Report., No. 18, 119P.Australia, New South WalesKimberley, Diamond Occurrences
DS1950-0138
1953
Holmes, M.Holmes, M.The Crown JewelsLondon: Ministry of Works, 26P.GlobalDiamonds Notable, Kimberley
DS1992-0722
1992
Holmes, M.Holmes, M.The irresistible fluid and the immovable rockNew Scientist, March 21, pp.41-45GlobalPetrology, Fluid migration in rocks
DS200612-0598
2006
Holmes, P.Holmes, P., Pell, J., Mathison, W., Strickland, D., Harder, M.New sparkle at the DO-27 diamond project.CIM Conference and Exhibition, Vancouver - Creating Value with Values, List of talks CIM Magazine, Feb. p. 78.Canada, Northwest TerritoriesOverview - Peregrine
DS200912-0310
2009
Holmes, P.Holmes, P., Pell, J., Clements, B., Grenon, H., Sell, M.The Chidliak diamond project, Baffin Island, one year after initial discovery.37th. Annual Yellowknife Geoscience Forum, Abstracts p. 24.Canada, Nunavut, Baffin IslandHistory
DS201212-0295
2012
Holmes, P.Herman, L.M., Grutter, H.S., Pell, J., Holmes, P., Grenon, H.U-Pb geochronology , SR and ND isotope compositions of groundmass perovskite from the Chidliak and Qilaq kimberlites, Baffin Island, Nunavut.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, Nunavut, Baffin IslandDeposit - Chidliak, Qilaq
DS1995-1171
1995
Holmes, P.J.Marker, M.E., Holmes, P.J.Lunette dunes in the northeast Cape, South Africa: as geomorphic indicators of palaeoenvironmental change.Catena, Vol. 24, No. 4, Oct. 1, pp. 259-274.South AfricaGeomorphology, Paleoenvironment
DS200812-0483
2008
Holmes, P.K.Holmes, P.K., Grenon, H., Self, M.V., Pell, J., Neilson, S.The Chidliak property, a new diamond district on Baffin Island, Nunavut.Northwest Territories Geoscience Office, p. 35. abstractCanada, Nunavut, Baffin IslandBrief overview - Peregrine
DS1983-0105
1983
Holmes, R.D.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
Holmes, R.D.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
DS1950-0107
1952
Holmes, S.W.Holmes, S.W.Structural Geology and Igneous Rocks of South Central New York and Vicinity.The Compass of Sigma Gamma Epsilon., Vol. 29, No. 3, PP. 266-272.United States, Appalachia, New YorkGeotectonics
DS2002-1503
2002
Holmgren, C.Skewes, M.A., Holmgren, C., Stern, C.R.The Donoso copper rich tourmaline bearing breccia pipe in central Chile: petrologic, fluid inclusion, isotopeMineralium Deposita, Vol.ChileCopper, magmatism, metallogeny, Deposit - Donoso
DS201212-0080
2012
Holm-Muller, K.Boos, A., Holm-Muller, K.A theoretical overview of the relationship between the resouce curse and genuine savings as an indicator for "weak" sustainability.Natural Resources Forum, Vol. 36, 3, pp. 145-159.GlobalEconomics
DS1860-0800
1893
Holmquist, P.J.Holmquist, P.J.Pyrochlor Fran AlnonGeol. Foren. Forhandl., Vol. 15, No. 7, PP. 588-606.Europe, Sweden, ScandinaviaAlnoite
DS1860-0848
1894
Holmquist, P.J.Holmquist, P.J.Knopit, Ett Perowskit Narstaende Nytt Mineral Fran AlnonGeol. Foren. Forhandl., Vol. 16. PP. 73-95.Europe, Sweden, ScandinaviaAlnoite
DS200712-0450
2006
Holness, M.Holness, M.How melted rock migrates.Science, Vol. 314, Nov. 10, pp. 934-935.MantleMelting
DS201112-0444
2011
Holness, M.B.Holness, M.B., Cesare, B., Sawyer, E.W.Melted rocks under the microscope: microstructures and their interpretation.Elements, Vol. 7, 4, August pp. 247-252.TechnologyMigmatites
DS200812-0722
2008
Holohan, E.P.Mathieu, L., Van Wyk de Vries, B., Holohan, E.P., Troll, V.R.Dykes, cups, saucers, sills: analogue experiments on magma intrusion into brittle rocks.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 1-13.MantleMagmatism
DS200812-0723
2008
Holohan, E.P.Mathieu, L., Van Wyk de Vries, B., Holohan, E.P., Troll, V.R.Dykes, cups, saucers and sills: analogue experiments on magma intrusion into brittle rocks.Earth and Planetary Science Letters, Vol. 271, 1-4, pp. 1-13.MantleMagmatism
DS1995-1153
1995
Holopova, E.B.Malkov, B.A., Holopova, E.B.Epochs and cycles of diamond genesis in cratons and mobile beltsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 345-347.RussiaTectonic cycles, Diamond genesis
DS1992-0723
1992
Holroyd, F.Holroyd, F., Bell, S.B.Raster GIS: models of raster encodingComputers and Geosciences, Vol. 18, No. 4, pp. 419-426GlobalComputers, Programs -Geographic information systems, raster encodi
DS200512-0641
2005
Holsa, J.Lindblom, J., Holsa, J., Papunen, H., Hakkanen, H.Luminescence study of defects in synthetic as grown and HPHT diamonds compared to natural diamonds.American Mineralogist, Vol. 90, Feb-Mar. pp. 428-440.Cathodluminescence
DS200512-0642
2005
Holsa, J.Lindblom, J., Holsa, J., Papunen, H., Hakkanen, H.Luminescence study of defects in synthetic as-grown and HPHT diamonds compared to natural diamonds.American Mineralogist, Vol. 90, pp. 428-440.Photoluminescence technology, UHP
DS200612-0778
2006
Holschneider, M.Le Mouel, J.L., Narteau, C., Greff-Lefftz, M., Holschneider, M.Dissipation at the core mantle boundary on a small scale topography.Journal of Geophysical Research, Vol. 111, 10p. B04413MantleCMB - friction
DS1989-1148
1989
Holst, T.B.Ojakangas, R.W., Green, J.C., Holst, T.B.35th. Annual Institute on Lake Superior Geology,Proceedings andAbstracts, held Duluth Minnesota,May 4-5, 1989Institute Lake Superior Geology, 35th. VolumeMinnesota, MichiganMid continent, Tectonics
DS1991-0726
1991
Holst, T.B.Holst, T.B.The Penokean Orogeny in Minnesota and Upper Michigan- a comparison of structural geologyUnited States Geological Survey (USGS) Bulletin, No. 1904-D, 13pMinnesota, MichiganTectonics, Structure
DS1991-0727
1991
Holst, T.B.Holst, T.B.The Penokean Orogeny in Minnesota and upper Michigan: a comparison of structural geologyUnited States Geological Survey (USGS) Bulletin, No. B 1904-C, D, pp. D 1-10Minnesota, MichiganTectonics, Structure
DS1991-1642
1991
Holst, T.B.Southwick, D.L., Morey, G.B., Holst, T.B.Tectonic imbrication and foredeep development in the Penokean Orogeny, east central Minnesota: an interpretation based on regional geophysics and drillUnited States Geological Survey (USGS) Bulletin, No. 1904 C-D, 17p. and 10pMinnesotaTectonics, Penokean Orogeny
DS1993-0693
1993
Holst, T.B.Holm, D.K., Holst, T.B., Lux, D.R.Post collisional cooling of the Penokean orogen in east-central MinnesotaCanadian Journal of Earth Sciences, Vol. 30, No. 5, May pp. 913-917MinnesotaTectonics, Geochronology
DS1930-0165
1934
Holstein-KochHolstein-KochSeele der EdelsteineLeipzig:, GlobalKimberlite, Kimberley, Janlib, Gemology
DS201809-2043
2018
Holstrom, S.Ivarsson, M., Skogby, H., Bengtson, S., Siljestrom, S., Ounchanum, P., Boonsoong, A., Kruachanta, M., Marone, F., Belivanova, V., Holstrom, S.Intricate tunnels in garnets from soils and river sediments in Thailand - possible endolithic microborings.PluS One, Vol. 13, 8, doi:10.1371/journal.pone.0200351Asia, Thailandgarnets

Abstract: Garnets from disparate geographical environments and origins such as oxidized soils and river sediments in Thailand host intricate systems of microsized tunnels that significantly decrease the quality and value of the garnets as gems. The origin of such tunneling has previously been attributed to abiotic processes. Here we present physical and chemical remains of endolithic microorganisms within the tunnels and discuss a probable biological origin of the tunnels. Extensive investigations with synchrotron-radiation X-ray tomographic microscopy (SRXTM) reveal morphological indications of biogenicity that further support a euendolithic interpretation. We suggest that the production of the tunnels was initiated by a combination of abiotic and biological processes, and that at later stages biological processes came to dominate. In environments such as river sediments and oxidized soils garnets are among the few remaining sources of bio-available Fe2+, thus it is likely that microbially mediated boring of the garnets has trophic reasons. Whatever the reason for garnet boring, the tunnel system represents a new endolithic habitat in a hard silicate mineral otherwise known to be resistant to abrasion and chemical attack.
DS201804-0708
2018
Holt, A.F.Kiraly, A., Holt, A.F., Funiciello, F., Faccenna, C., Capitanio, F.A.Modeling slab-slab interactions: dynamics of outward dipping double sided subduction systems.Geochemistry, Geophysics, Geosystems, 22p. PdfMantleplate tectonics

Abstract: Slab-slab interaction is a characteristic feature of tectonically complex areas. Outward dipping double-sided subduction is one of these complex cases, which has several examples on Earth, most notably the Molucca Sea and Adriatic Sea. This study focuses on developing a framework for linking plate kinematics and slab interactions in an outward dipping subduction geometry. We used analog and numerical models to better understand the underlying subduction dynamics. Compared to a single subduction model, double-sided subduction exhibits more time-dependent and vigorous toroidal flow cells that are elongated (i.e., not circular). Because both the Molucca and Adriatic Sea exhibit an asymmetric subduction configuration, we also examine the role that asymmetry plays in the dynamics of outward dipping double-sided subduction. We introduce asymmetry in two ways; with variable initial depths for the two slabs (geometric asymmetry), and with variable buoyancy within the subducting plate (mechanical asymmetry). Relative to the symmetric case, we probe how asymmetry affects the overall slab kinematics, whether asymmetric behavior intensifies or equilibrates as subduction proceeds. While initial geometric asymmetry disappears once the slabs are anchored to the 660 km discontinuity, the mechanical asymmetry can cause more permanent differences between the two subduction zones. In the most extreme case, the partly continental slab stops subducting due to the unequal slab pull force. The results show that the slab-slab interaction is most effective when the two trenches are closer than 10-8 cm in the laboratory, which is 600-480 km when scaled to the Earth.
DS1984-0244
1984
Holt, R.W.Drury, S.A., Harris, N.B.W., Holt, R.W., Reeves-Smith, G.J.Precambrian Tectonics and Crustal Evolution in South IndiaJournal of GEOLOGY, Vol. 92, PP. 3-20.IndiaGeotectonics
DS1900-0765
1909
Holt, S.T.Holt, S.T.The Diamond- a Short and Snappy Account of its Occurrence, Characters and Applications in Jewellery.Newark: Frank Holt And Co., 35P.GlobalKimberlite
DS200712-0319
2007
Holt, W.E.Flesch, L.M., Holt, W.E., Haines, A.J., Wen, L., Shen-Tu BingmingThe dynamics of western North America: stress magnitudes and the relative role of gravitational potential energy, plate interaction, boundary and basalGeophysical Journal International, Vol. 169, 3, pp. 866-896.United States, CanadaTectonics
DS200712-0989
2006
Holt, W.E.Silver, P.G., Hahn, B.C., Kreemer, C., Holt, W.E., Haines, J.Convergent margins, growing and shrinking continents, and the Wilson cycle.Geological Society of America Annual Meeting, Vol. 38, 7, Nov. p. 212 abstractUnited StatesBasin and Range, Wilson Cycle
DS200812-0405
2008
Holt, W.E.Ghosh, A., Holt, W.E., Wen, L., Haines, A.J., Flesch, L.M.Joint modeling of lithosphere and mantle dynamics elucidating lithosphere mantle coupling.Geophysical Research Letters, Vol. 35, 16, L16309-10.MantleTectonics
DS201212-0239
2012
Holt, W.E.Ghosh, A., Holt, W.E.Plate motions and stresses from global dynamic models.Science, Vol. 335, 6070, pp. 838-843.MantleGeodynamics
DS201603-0413
2016
Holt, W.E.Porter, R., Liu, Y., Holt, W.E.Lithospheric records of orogeny within the continental US.Geophysical Research Letters, Vol. 43, 1, pp. 144-153.United StatesGeophysics - gradiometry

Abstract: In order to better understand the tectonic evolution of the North American continent, we utilize data from the EarthScope Transportable Array network to calculate a three-dimensional shear velocity model for the continental United States. This model was produced through the inversion of Rayleigh wave phase velocities calculated using ambient noise tomography and wave gradiometry, which allows for sensitivity to a broad depth range. Shear velocities within this model highlight the influence of orogenic and postorogenic events on the evolution of the lithosphere. Most notable is the contrast in crustal and upper mantle structure between the relatively slow western and relatively fast eastern North America. These differences are unlikely to stem solely from thermal variations within the lithosphere and highlight both the complexities in lithospheric structure across the continental U.S. and the varying impacts that orogeny can have on the crust and upper mantle.
DS201603-0430
2015
Holt, W.E.Wang, X., Holt, W.E., Ghosh, A.Joint modeling of lithosphere and mantle dynamics: evaluation of constraints from global tomography models.Journal of Geophysical Research,, Vol. 120, 12, pp. 8633-8655.MantleGeodynamics

Abstract: With the advances in technology, seismological theory, and data acquisition, a number of high-resolution seismic tomography models have been published. However, discrepancies between tomography models often arise from different theoretical treatments of seismic wave propagation, different inversion strategies, and different data sets. Using a fixed velocity-to-density scaling and a fixed radial viscosity profile, we compute global mantle flow models associated with the different tomography models and test the impact of these for explaining surface geophysical observations (geoid, dynamic topography, stress, and strain rates). We use the joint modeling of lithosphere and mantle dynamics approach of Ghosh and Holt (2012) to compute the full lithosphere stresses, except that we use HC for the mantle circulation model, which accounts for the primary flow-coupling features associated with density-driven mantle flow. Our results show that the seismic tomography models of S40RTS and SAW642AN provide a better match with surface observables on a global scale than other models tested. Both of these tomography models have important similarities, including upwellings located in Pacific, Eastern Africa, Iceland, and mid-ocean ridges in the Atlantic and Indian Ocean and downwelling flows mainly located beneath the Andes, the Middle East, and central and Southeast Asia.
DS2002-1484
2002
Holt. W.E.Silver, P.G., Holt. W.E.The mantle flow field beneath western North AmericaScience, No. 5557, Feb. 8, pp. 1054-7.North America, CordilleraGeophysics - seismics
DS1900-0670
1908
Holte, P.B.Holte, P.B.Alluvial Diamond MiningMines and MIN. (SCRANTON), Vol. 29, AUGUST P. 37.Africa, South AfricaMining Engineering
DS201803-0462
2017
Holtgrewe, N.Lobanov, S.S., Holtgrewe, N., Lin, J-F, Goncharov, A.F.Radiative conductivity and abundance of post perovskite in the lower most mantle.Earth and Planetary Science Letters, Vol. 479, pp. 43-49.Mantleperovskite

Abstract: Thermal conductivity of the lowermost mantle governs the heat flow out of the core energizing planetary-scale geological processes. Yet, there are no direct experimental measurements of thermal conductivity at relevant pressure-temperature conditions of Earth's core-mantle boundary. Here we determine the radiative conductivity of post-perovskite at near core-mantle boundary conditions by optical absorption measurements in a laser-heated diamond anvil cell. Our results show that the radiative conductivity of Mg0.9Fe0.1SiO3 post-perovskite (~1.1 W/m/K) is almost two times smaller than that of bridgmanite (~2.0 W/m/K) at the base of the mantle. By combining this result with the present-day core-mantle heat flow and available estimations on the lattice thermal conductivity we conclude that post-perovskite is at least as abundant as bridgmanite in the lowermost mantle which has profound implications for the dynamics of the deep Earth.
DS202002-0204
2019
Holtgrewe, N.Lobanov, S.S., Holtgrewe, N., Ito, G., Badro, J., Piet, H., Babiel, F., Lin, J-F., Bayarjargal, L., Wirth, R., Schrieber, A., Goncharov, A.F.Blocked radiative heat transport in the hot pyrolitic lower mantle.Researchgate.com, 32p. PdfMantlegeothermometry

Abstract: The heat flux across the core-mantle boundary (QCMB) is the key parameter to understand the Earth/s thermal history and evolution. Mineralogical constraints of the QCMB require deciphering contributions of the lattice and radiative components to the thermal conductivity at high pressure and temperature in lower mantle phases with depth-dependent composition. Here we determine the radiative conductivity (krad) of a realistic lower mantle (pyrolite) in situ using an ultra-bright light probe and fast time-resolved spectroscopic techniques in laser-heated diamond anvil cells. We find that the mantle opacity increases critically upon heating to ~3000 K at 40-135 GPa, resulting in an unexpectedly low radiative conductivity decreasing with depth from ~0.8 W/m/K at 1000 km to ~0.35 W/m/K at the CMB, the latter being ~30 times smaller than the estimated lattice thermal conductivity at such conditions. Thus, radiative heat transport is blocked due to an increased optical absorption in the hot lower mantle resulting in a moderate CMB heat flow of ~8.5 TW, at odds with present estimates based on the mantle and core dynamics. This moderate rate of core cooling implies an inner core age of about 1 Gy and is compatible with both thermally- and compositionally-driven ancient geodynamo.
DS1990-0715
1990
Holtkamp, J.A.Holtkamp, J.A.Mining waste regulations. 3 brief pages -slide headingsNorthwest Mining Association Preprint, 3pUnited StatesLegal, Mining waste
DS1992-0724
1992
Holton, J.R.Holton, J.R.An introduction to dynamic meteorologyAcademic Press, 511p. approx. $ 45.00 United StatesGlobalBook -ad, Meteorology
DS1995-0818
1995
Holton, J.R.Holton, J.R., Haynes, P.H., McIntyre, M.E., Douglass, A.Stratosphere- Troposphere exchangeReviews of Geophysics, Vol. 33, No. 4, Nove, pp. 403-439GlobalGlobal change, Review
DS201809-2035
2018
Holtstam, D.Holtstam, D., Camara, F., Skogby, H., Karlsson, A., Langhof, J.Description and recognition of potassic richterite, an amphibole supergroup mineral from the Pajsberg ore field, Varmland, Sweden.Mineralogy and Petrology, doi.org/101007/ s00710-018-0623-6 10p.Europe, Swedenalkaline

Abstract: Potassic-richterite, ideally AKB(NaCa)CMg5TSi8O22W(OH)2, is recognized as a valid member of the amphibole supergroup (IMA-CNMNC 2017-102). Type material is from the Pajsberg Mn-Fe ore field, Filipstad, Värmland, Sweden, where the mineral occurs in a Mn-rich skarn, closely associated with mainly phlogopite, jacobsite and tephroite. The megascopic colour is straw yellow to grayish brown and the luster vitreous. The nearly anhedral crystals, up to 4 mm in length, are pale yellow (non-pleochroic) in thin section and optically biaxial (-), with a?=?1.615(5), ß?=?1.625(5), ??=?1.635(5). The calculated density is 3.07 g•cm-1. VHN100 is in the range 610-946. Cleavage is perfect along {110}. EPMA analysis in combination with Mössbauer and infrared spectroscopy yields the empirical formula (K0.61Na0.30Pb0.02)?0.93(Na1.14Ca0.79Mn0.07)?2(Mg4.31Mn0.47Fe3+0.20)?5(Si7.95Al0.04Fe3+0.01)?8O22(OH1.82F0.18)?2 for a fragment used for collection of single-crystal X-ray diffraction data. The infra-red spectra show absorption bands at 3672 cm-1 and 3736 cm-1 for the a direction. The crystal structure was refined in space group C2/m to R1?=?3.6% [I >?2s(I)], with resulting cell parameters a?=?9.9977(3) Å, b?=?18.0409(4) Å, c?=?5.2794(2) Å, ??=?104.465(4)°, V?=?922.05(5) Å3 and Z?=?2. The A and M(4) sites split into A(m) (K+), A(2/m) (Na+), A(2) (Pb2+), and M(4') (Mn2+) subsites, respectively. The remaining Mn2+ is strongly ordered at the octahedrally coordinated M(2) site, possibly together with most of Fe3+. The skarn bearing potassic-richterite formed at peak metamorphism, under conditions of low SiO2 and Al2O3 activities and relatively high oxygen fugacities.
DS2000-0419
2000
Holtta, P.Holtta, P., Huhma, H., Juhanoja, J.Petrology and geochemistry of mafic granulite xenoliths from the Lahtojoki kimberlite pipe, eastern Finland.Lithos, Vol. 51, No. 1-2, pp. 109-133.FinlandXenoliths
DS2000-0970
2000
Holtta, P.Vaisanen, M., Mantarri, I., Kriegsman, L.M., Holtta, P.Tectonic setting of post collisional magmatism in the Paleoproterozoic Svecofennian Orogen, southwest Finland.Lithos, Vol. 54, No. 1-2, Oct. pp. 63-81.FinlandTectonics, mantle enrichment, magmatism
DS2002-1628
2002
Holtta, P.Vaisanen, M., Manttari, I., Holtta, P.Svecofennian magmatic and metamorphic evolution in southwestern FIn land as revealed by U Pb zircon SIMS geochronology.Precambrian Research, Vol. 116, No.1-2, pp. 111-27.FinlandMagmatism, Geochronology
DS201112-0445
2011
Holtz, F.Holtz, F.Transport of High-Field Strength Elements and noble metals in silicate melts.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, AbstractMelting
DS201605-0895
2016
Holtz, F.Scaillet, B., Holtz, F., Pichavant, M.Enigmatic relationship between silicic volcanic and plutonic rocks: experimental constraints on the formation of silicic magmas.Elements, Vol. 12, pp. 109-114.TechnologyMagmatism
DS201810-2304
2018
Holtz, F.Cheng, Z., Zhang, Z., Aibai, A., Kong, W., Holtz, F.The role of magmatic and post-magmatic hydrothermal processes on rare earth element mineralization: a study of the Bachu carbonatites from the Tarim Large Igneous Province, NW China.Lithos, Vol. 314-315, pp. 71-87.Chinacarbonatite

Abstract: The contribution of magmatic and hydrothermal processes to rare earth element (REE) mineralization of carbonatites remains an area of considerable interest. With the aim of better understanding REE mineralization mechanisms, we conducted a detailed study on the petrology, mineralogy and C-O isotopes of the Bachu carbonatites, NW China. The Bachu carbonatites are composed predominantly of magnesiocarbonatite with minor calciocarbonatite. The two types of carbonatite have primarily holocrystalline textures dominated by dolomite and calcite, respectively. Monazite-(Ce) and bastnäsite-(Ce), the major REE minerals, occur as euhedral grains and interstitial phases in the carbonatites. Melt inclusions in the dolomite partially rehomogenize at temperatures above 800?°C, and those in apatite have homogenization temperatures (Th) ranging from 645 to 785?°C. Oxygen isotope ratios of the calciocarbonatite intrusions (d18OV-SMOW?=?6.4‰ to 8.3‰), similar to the magnesiocarbonatites, indicate the parental magma is mantle-derived, and that they may derive from a more evolved stage of carbonatite fractionation. The magnesiocarbonatites are slightly enriched in LREE whereas calciocarbonatites have higher HREE concentrations. Both dolomite and calcite have low total REE (TREE) contents ranging from 112 to 436?ppm and 88 to 336?ppm, respectively, much lower than the bulk rock composition of the carbonatites (371 to 36,965?ppm). Hence, the fractional crystallization of carbonates is expected to elevate REE concentrations in the residual magma. Rocks from the Bachu deposit with the highest TREE concentration (up to 20?wt%) occur as small size (2?mm to 3 cm) red rare earth-rich veins (RRV) with barite + celestine + fluorapatite + monazite-(Ce) associations. These rocks are interpreted to have a hydrothermal origin, confirmed by the fluid inclusions in barite with Th in the range 198-267?°C. Hydrothermal processes may also explain the existence of interstitial textures in the carbonatites with similar mineral assemblages. The C-O isotopic compositions of the RRV (d13CV-PDB?=?-3.6 to -4.3‰, d18OV-SMOW?=?7.6 to 9.8‰) are consistent with an origin resulting from fluid exsolution at the end of the high temperature fractionation trend. A two-stage model involving fractional crystallization and hydrothermal fluids is proposed for the mineralization of the Bachu REE deposit.
DS201807-1497
2018
Holtzhausen, C.Holtzhausen, C., Moodley, T.Practical roadmapping of technology and digital transformation in mining.SAIMM Diamonds - source to use 2018 Conference 'thriving in changing times'. June 11-13., pp. 65-72.Technologydigital solutions
DS202011-2049
2020
Holtzman, B.Lau, H., Holtzman, B., Havlin, C.Towards a self-consistent characterization of lithospheric plates using full-spectrum viscoelasticity.AGU Advances, dor.or/10.101029 /2020AV000205Mantletectonics

Abstract: On Earth, broken, rigid tectonic plates lie atop slowly flowing mantle rock (over millions to billions of years). A basic understanding of the global variation in thickness of this rigid lid provides the foundation to many geodynamical predictions. However, using different techniques to estimate its thickness, for example, seismic wave propagation (acting on timescales of seconds), to the warping of plates under the weight of volcanoes (acting on timescales of millions of years) reveals many inconsistencies. At the heart of these inconsistencies is the fact that rock deforms differently to forces acting on different timescales. At very fast timescales rock deforms like an elastic solid, but at much longer timescales, rock flows. To resolve these inconsistencies, we attempt to coherently tie these disparate observations together to reach a more holistic understanding of plate thickness, accounting for these timescale effects. By incorporating current understanding on rock deformation from laboratory experiments, we demonstrate that on fast timescales (of the seismic waves used to image the Earth's interior), tectonic plates appear significantly thicker than the true thickness at million- to billion-year timescales of plate tectonics. This demonstration involves a new theoretical and conceptual framework for interpreting distinct observations acting on vastly different timescales.
DS2003-0597
2003
Holtzman, B.K.Holtzman, B.K., Kohlstedt, D.L., Zimmerman, M.E., Heidelbach, F., Hiraga, T.Melt segregation and strain partitioning: implications for seismic anisotropy and mantleScience, No. 5637, August 29,p. 1227-29.MantleGeophysics - seismic
DS200412-0845
2003
Holtzman, B.K.Holtzman, B.K., Kohlstedt, D.L., Zimmerman, M.E., Heidelbach, F., Hiraga, T., Hustoft, J.Melt segregation and strain partitioning: implications for seismic anisotropy and mantle flow.Science, No. 5637, August 29,p. 1227-29.MantleGeophysics - seismic
DS200912-0394
2009
Holtzman, B.K.Kohlstedt, D.L., Holtzman, B.K.Shearing melt out of the Earth: an experimentalist's perpective on the influence of deformation on melt extraction.Annual Review of Earth and Planetary Sciences, Vol. 37, pp. 561-593.MantleMelting - review
DS1860-0366
1881
Holub, E.Holub, E.Sieben Jahre in Sued-afrika Erlebnisse, Forschungen und Jagden Auf Meinen Reisen von Den Diamant feldern Zum Zambesi (1872-1879).Wien: Two Volumes, 426P. AND 479P. ALSO: LONDON: ENGLISH EDITION; ALSO: AFRICANAfrica, South Africa, Cape ProvinceHistory
DS1860-0941
1896
Holub, E.Holub, E.A Brief History of the Discovery, and an Account of the Working of the Diamond Mines.Illustrated Christian World (new York), No. 92, AUGUST, P. 7.Africa, South Africa, Cape ProvinceHistory
DS1860-0942
1896
Holub, E.Holub, E.Location of the Diamond Fields and Their Geological Formations.Illustrated Christian World (new York), No. 93, SEPT., P. 7.History, South Africa, Cape ProvinceHistory
DS2001-0486
2001
Holubec, I.Holubec, I., Saul, B.Mine waste management strategy at Diavik Diamonds mine29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p. 30-1.Northwest TerritoriesMine waste - environment, tailings, Deposit - Diavik
DS200512-0443
2004
Holubec, I.Holubec, I.Typical dam designs in permafrost.32nd Yellowknife Geoscience Forum, Nov. 16-18, p.34. (talk)Canada, Northwest TerritoriesMining - dam designs (Diavik)
DS1900-0255
1904
Holway, R.S.Holway, R.S.Eclogites in CaliforniaJournal of Geology, Vol. 12, PP. 244-258.United States, California, West CoastEclogites
DS202001-0016
2019
Holwell, D.A.Holwell, D.A., Fiorentini, M., McDonald, I., Lu, Y., Giuliani, A., Smith, D.J., Keith, M., Locmelis, M.A metasomatized lithospheric mantle control on the metallogenic signature of post-subduction magmatism. ( Not specific to diamonds)Nature Communications, doi.org/10.1038/s41467-019-11065-4 pdf 10p.Mantlesubduction

Abstract: Ore deposits are loci on Earth where energy and mass flux are greatly enhanced and focussed, acting as magnifying lenses into metal transport, fractionation and concentration mechanisms through the lithosphere. Here we show that the metallogenic architecture of the lithosphere is illuminated by the geochemical signatures of metasomatised mantle rocks and post-subduction magmatic-hydrothermal mineral systems. Our data reveal that anomalously gold and tellurium rich magmatic sulfides in mantle-derived magmas emplaced in the lower crust share a common metallogenic signature with upper crustal porphyry-epithermal ore systems. We propose that a trans-lithospheric continuum exists whereby post-subduction magmas transporting metal-rich sulfide cargoes play a fundamental role in fluxing metals into the crust from metasomatised lithospheric mantle. Therefore, ore deposits are not merely associated with isolated zones where serendipitous happenstance has produced mineralisation. Rather, they are depositional points along the mantle-to-upper crust pathway of magmas and hydrothermal fluids, synthesising the concentrated metallogenic budget available.
DS1950-0139
1953
Holyk, W.Holyk, W., Ahrens, L.H.Potassium in Ultramafic RocksGeochim Et Cosmochim. Acta., Vol. 4, PP. 241-250.South AfricaPetrology
DS200512-0444
2005
Holzapel, C.Holzapel, C., Rubie, D.C., Frost, D.J., Langenhorst, F.Geophysics: Fe Mg interdiffusion in (Mg,Fe) SiO3 perovskite and lower mantle requilibration.Science, No. 5741, Sept. 9, pp. 1707-1710.MantleGeophysics
DS201012-0213
2010
HolzapfelFrost, D.F., Asahara, Y., Rubie, D.C., Miyajima, N., Dubrovinsky, Holzapfel, Ohtani, Miyahara, SakaiPartitioning of oxygen between the Earth's mantle and core.Journal of Geophysical Research, Vol. 115, B2 , B02202.MantleChemistry
DS200812-1187
2008
Holzapfel, W.B.Tse, J.S., Holzapfel, W.B.Equation of state for diamond in wide ranges of pressure and temperature.Journal of Applied Physics, (American Institute of Physices), Vol. 104, 4, August 15 043525TechnologyDiamond morphology
DS1998-0638
1998
HolzelHolzelWorld atlas of resources and environmenthttp://geoserve.us Clearance sale was $ 550., $49. US customers (outside $ 180.00)GlobalBook - atlas
DS200412-0846
1998
HolzelHolzelWorld atlas of resources and environment.geoserve.us Clearance sale was $ 550., $49. US customers (outside $ 180.00)GlobalBook - atlas
DS1990-0716
1990
Holzel, A.R.Holzel, A.R.Systematics of mineralsHolzel, Ulmenring, language presumed english, 584p. approx. DM 380.00GlobalMineralogy, Book review
DS1999-0627
1999
HolzerSchaller, M., Steiner, O., Studer, I., Holzer, HerweghExhumation of Limpopo Central Zone granulites and dextral continent scale transcurrent movement...Precambrian Research, Vol. 96, No. 3-4. July, pp. 263-88.South AfricaPalala Shear Zone, Limpopo - tectonics
DS1984-0018
1984
Holzer, G.Andrawes, F., Holzer, G., Roedder, E., Gibson, E.K., Oro, J.Gas Chromatographic Analysis of Volatiles in Fluid and Gas Inclusions.Journal of Chromatography, Vol. 302, PP. 181-193.GlobalFluid Inclusions, Diamonds, Geochemistry
DS1994-0115
1994
Holzer, L.Barton, J.M. Jr., Holzer, L.Discrete metamorphic events in the Limpopo Belt, southern Africa:implications for the P-T pathsGeology, Vol. 22, No. 11, November pp. 1035-38Africa, South Africa, ZimbabweMetamorphic terrains, Tectonics, Limpopo belt
DS1998-0639
1998
Holzforster, F.Holzforster, F., Stollhofen, H., Lorenz, StanistreetThe Waterberg Basin in central Namibia: transfer fault activity during early South Atlantic rift evolution.Journal of African Earth Sciences, Vol. 27, 1A, p. 116. AbstractNamibiaTectonics
DS1998-1107
1998
HolzheidPalme, H., Borisov, A., Holzheid, SchmidtOrigin and significance of highly siderophile elements in the upper mantle of the earth.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1127-8.MantleHSE silicate melts
DS2000-0420
2000
Holzheid, A.Holzheid, A., Sylvester, P., Palme, H.Evidence for a late chondritic veneer in the Earth's mantle from high pressure pressure partitioning of palladium &PtNature, Vol. 406, No.6794, July27, pp. 396-8.MantleChondrites
DS200512-0097
2004
Holzheid, A.Bockrath, C., Ballhaus, C., Holzheid, A.Fractionation of the platinum group elements during mantle melting.Science, No. 5692, Sept. 24, pp. 1951-1952.MantleGeochemistry
DS201112-0885
2011
Holzheid, A.Rubie, D.C., Frost, D.J., Mann, U., Asahara, Y., Nimmo, F., Tsuno, K., Kegler, P., Holzheid, A., Palme, H.Heterogeneous accretion, composition and core-mantle differentiation of the Earth.Earth and Planetary Science Letters, Vol. 301, 1-2, pp. 31-42.MantleAccretion
DS201705-0809
2017
Holzheid, A.Benaouda, R., Holzheid, A., Schenk, V., Badra, L., Ennaciri, A.Magmatic evolution of the Jbel Boho alkaline complex in the Bou Azzer In lier ( Anti-Atlas/Morocco) and its relation to REE Mineralization.Journal of African Earth Sciences, Vol. 129, pp. 202-223.Africa, MoroccoAlkaline rocks

Abstract: The Jbel Boho complex (Anti-Atlas/Morocco) is an alkaline magmatic complex that was formed during the Precambrian-Cambrian transition, contemporaneous with the lower early Cambrian dolomite sequence. The complex consists of a volcanic sequence comprising basanites, trachyandesites, trachytes and rhyolites that is intruded by a syenitic pluton. Both the volcanic suite and the pluton are cut by later microsyenitic and rhyolitic dykes. Although all Jbel Boho magmas were probably ultimately derived from the same, intraplate or plume-like source, new geochemical evidence supports the concept of a minimum three principal magma generations having formed the complex. Whereas all volcanic rocks (first generation) are LREE enriched and appear to be formed by fractional crystallization of a mantle-derived magma, resulting in strong negative Eu anomalies in the more evolved rocks associated with low Zr/Hf and Nb/Ta values, the younger syenitic pluton displays almost no negative Eu anomaly and very high Zr/Hf and Nb/Ta. The syenite is considered to be formed by a second generation of melt and likely formed through partial melting of underplated mafic rocks. The syenitic pluton consists of two types of syenitic rocks; olivine syenite and quartz syenite. The presence of quartz and a strong positive Pb anomaly in the quartz syenite contrasts strongly with the negative Pb anomaly in the olivine syenite and suggests the latter results from crustal contamination of the former. The late dyke swarm (third generation of melt) comprises microsyenitic and subalkaline rhyolitic compositions. The strong decrease of the alkali elements, Zr/Hf and Nb/Ta and the high SiO2 contents in the rhyolitic dykes might be the result of mineral fractionation and addition of mineralizing fluids, allowing inter-element fractionation of even highly incompatible HFSE due to the presence of fluorine. The occurrence of fluorite in some volcanic rocks and the Ca-REE-F carbonate mineral synchysite in the dykes with very high LREE contents (Ce ~720 ppm found in one rhyolitic dyke) suggest the fluorine-rich nature of this system and the role played by addition of mineralizing fluids. The REE mineralization expressed as synchysite-(Ce) is detected in a subalkaline rhyolitic dyke (with SLREE = 1750 ppm) associated with quartz, chlorite and occasionally with Fe-oxides. The synchysite mineralization is probably the result of REE transport by acidic hydrothermal fluids as chloride complex and their neutralization during fluid-rock interaction. The major tectonic change from compressive to extensional regime in the late Neoproterozoic induced the emplacement of voluminous volcaniclastic series of the Ediacran Ouarzazate Group. The alkaline, within-plate nature of the Jbel Boho igneous complex implies that this extensional setting continued during the early Cambrian.
DS1982-0281
1982
Holzschuh, E.Holzschuh, E., et al.Muonium in DiamondPhysical Review A, American Institute Physics, Vol. 25, No. 3, PP. 1272-1286.GlobalBlank
DS200812-1121
2008
Home, R.Steinberger, B., Home, R.Mantle flow models with core-mantle boundary constraints and chemical heterogeneities in the lowermost mantle.Journal of Geophysical Research, Vol. 113, B )5403MantleMantle flow, core-mantle boundary
DS201112-0446
2011
Home, R.Home, R., Olsen, N., Bairstow, F.L.Mapping geomagnetic secular variation at the core-mantle boundary.Geophysical Journal International, Vol. 186, 2, pp. 521-528.MantleGeophysics - magnetics
DS201911-2552
2019
Homman, K.Ortiz, K., Nyblade, A., Meijde, M., Paulssen, H., Kwadiba, M., Ntibinyane, O., Durheim, R., Fadel, I., Homman, K.Upper mantle P and S wave velocity structure of the Kalahari craton and surrounding Proterozoic terranes, southern Africa.Geophysical Research Letters, Vol. 46, 16, pp. 9509-9518.Africa, South Africageophysics - seismics

Abstract: P and S waves travel times from large, distant earthquakes recorded on seismic stations in Botswana and South Africa have been combined with existing data from the region to construct velocity models of the upper mantle beneath southern Africa. The models show a region of higher velocities beneath the Rehoboth Province and parts of the northern Okwa Terrane and the Magondi Belt, which can be attributed to thicker cratonic lithosphere, and a region of lower velocities beneath the Damara-Ghanzi-Chobe Belt and Okavango Rift, which can be attributed a region of thinner off-craton lithosphere. This finding suggests that the spatial extent of thick cratonic lithosphere in southern Africa is greater than previously known. In addition, within the cratonic lithosphere an area of lower velocities is imaged, revealing parts of the cratonic lithosphere that may have been modified by younger magmatic events.
DS200412-0439
2004
Homonnay, Z.Demeny, A., Vennemann, T.W., Hegner, E., Nagy, G., Milton, J.A., Embey-Isztin, A., Homonnay, Z., Dobosi, G.Trace element and C O Sr Nd isotope evidence for subduction related carbonate silicate melts in mantle xenoliths ( Pannonian BasLithos, Vol. 75, 1-2, July pp. 89-113.Europe, HungarySubduction, trace element fingerprinting, petrogenetic
DS201112-0958
2011
Homonnay, Z.Siidra, O.I., Spratt, J., Demeny, A., Homonnay, Z., Markl, G., Zaitsev, A.N.Cation distribution in the crystal structure of a new amphibole group mineral from the Deeti volcanic cone, northern Tanzania.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterAfrica, TanzaniaAlkalic
DS201806-1227
2018
Homrighausen, S.Homrighausen, S., Hoernle, K., Hauff, J., Geldmacher, J., Garbe-Schonberg, D.Global distribution of the HIMU end member: formation through Archean plume lid tectonics.Earth Science Reviews, Vol. 182, pp. 85-101.Globaltectonics

Abstract: Oceanic basalts reflect the heterogeneities in the earth's mantle, which can be explained by five mantle end members. The HIMU end member, characterized by high time-integrated µ (238U/204Pb), is defined by the composition of lavas from the ocean islands of St. Helena, South Atlantic Ocean and Mangaia and Tubuai (Cook-Austral Islands), South Pacific Ocean. It is widely considered to be derived from a mantle reservoir that is rarely sampled and not generally involved in mixing with the other mantle components. On the other hand, the FOZO end member, located at the FOcal ZOne of oceanic volcanic rock arrays on isotope diagrams, is considered to be a widespread common component with slightly less radiogenic 206Pb/204Pb and intermediate Sr-Nd-Hf isotopic compositions. Here we present new major and trace element, Sr-Nd-Pb-Hf isotope and geochronological data from the Walvis Ridge and Richardson Seamount in the South Atlantic Ocean and the Manihiki Plateau and Eastern Chatham Rise in the southwest Pacific Ocean. Our new data, combined with literature data, document a more widespread (nearly global) distribution of the HIMU end member than previously postulated. Our survey shows that HIMU is generally associated with low-volume alkaline, carbonatitic and/or kimberlitic intraplate volcanism, consistent with derivation from low degrees of melting of CO2-rich sources. The majority of end member HIMU locations can be directly related to hotspot settings. The restricted trace element and isotopic composition (St. Helena type HIMU), but near-global distribution, point to a deep-seated, widespread reservoir, which most likely formed in the Archean. In this context we re-evaluate the origin of a widespread HIMU reservoir in an Archean geodynamic setting. We point out that the classic ocean crust recycling model cannot be applied in a plume-lid dominated tectonic setting, and instead propose that delamination of carbonatite-metasomatized subcontinental lithospheric mantle could be a suitable HIMU source.
DS1985-0295
1985
Honda, M.Honda, M., Reynolds, J.H., Roedder, E.Noble Gases in Diamonds from Different LocationsEos, Vol. 66, No. 46, p. 1117. abstract onlyAustralia, Brazil, Zaire, South Africa, Arkansas, South AmericaBlank
DS1987-0298
1987
Honda, M.Honda, M., Reynolds, J.H., Roedder, E., Epstein, S.Noble gases in diamonds: occurrences of solarlike helium and neonJournal of Geophysical Research, Vol. 92, No. B12, November 10, pp. 12, 507-12, 522GlobalBlank
DS1996-1456
1996
Honda, M.Valbracht, P.J., Honda, M., Weis, D.Helium, neon and argon isotope systematics in Kerguelen ultramaficxenoliths:mantle source signaturesEarth and Planetary Science Letters, Vol. 138, No. 1/4, Feb. 1, pp. 29-38.MantleGeochronology, Xenoliths
DS1998-0963
1998
Honda, M.Matsumoto, T., Honda, M., McDougall, O'Reilly, S.Y.Noble gases in an anhydrous lherzolites from the Newer Volcanics, southeastern Australia: Mid Ocean Ridge Basalt (MORB) like...Geochimica et Cosmochimica Acta, Vol. 62, No. 14, July, pp. 2521-34.AustraliaMantle - subcontinental, Geochemistry
DS2000-0633
2000
Honda, M.Matsumoto, T., Honda, M., Yaxley, G.Noble gases in pyroxenites and metasomatised peridotites from Newer Volcanics, Mantle MetasomatismChemical Geology, Vol. 168, No. 1-2, July 1, pp. 49-74.Australia, SoutheastMetasomatism, Geochemistry
DS2002-0735
2002
Honda, M.Honda, M.Unusual noble gas compositions in polycrystalline diamonds: preliminary results from Jwaneng, Botswana.Geological Society of Australia Abstracts, Vol. 67, p. 210. abstract.BotswanaDiamond - morphology, Deposit - Jwaneng
DS2003-0598
2003
Honda, M.Honda, M., Nutman, A.P., Bennett, V.C.Xenon composition of magmatic zircons in 3.64 and 3.81 Ga meta-granitoids fromEarth and Planetary Science Letters, Vol. 207, 1-4, pp. 69-82.GreenlandMagmatism
DS200412-0847
2004
Honda, M.Honda, M., Phillips, D., Harris, J.W., Yatsevich, I.Unusual noble gas compositions in polycrystalline diamonds: preliminary results from the Jwaneng kimberlite, Botswana.Chemical Geology, Vol. 203, 3-4, Feb. 16, pp. 347-358.Africa, BotswanaMantle evolution, lithosphere, geochemistry
DS201012-0284
2010
Honda, M.Honda, M., Phillips, D., Harris, J., Matsumoto, T.Distinct neon isotope compositions found in polycrystalline diamonds and framesites from the Jwaneng kimberlite pipe, Botswana.Goldschmidt 2010 abstracts, abstractAfrica, BotswanaGeochronology
DS201112-0447
2011
Honda, M.Honda, M., Phillips, D., Harris, J.W., Matsumoto, T.He, Ne and Ar in peridotitic and eclogitic paragenesis diamonds from the Jwaneng kimberlite, Botswana - implications for mantle evolution and diamond formation ages.Earth and Planetary Science Letters, Vol. 301, 1-2, pp. 43-51.Africa, BotswanaGeocheonology - Jwaneng
DS201312-0400
2012
Honda, M.Honda, M., Phillips, D., Kendrick, M.A., Gagan, M.K., Taylor, W.R.Noble gas and carbon isotope ratios in Argyle diamonds, western Australia: evidence for a deeply subducted volatile component.Australian Journal of Earth Sciences, Vol. 59, 8, pp. 1135-1142.AustraliaDeposit - Argyle
DS201807-1532
2018
Honda, M.Timmerman, S., Honda, M., Phillips, D., Jaques, A.L., Harris, J.W.Noble gas geochemistry of fluid inclusions in South Africa diamonds: implications for the origin of diamond forming fluids. ( fibrous)Mineralogy and Petrology, 10.1007/ s710-018- 0603-x 15p.Africa, South Africadeposit - Finsch, De Beers Pool, Koffiefontein

Abstract: Fibrous diamond growth zones often contain abundant high-density fluid (HDF) inclusions and these provide the most direct information on diamond-forming fluids. Noble gases are incompatible elements and particularly useful in evaluating large-scale mantle processes. This study further constrains the evolution and origin of the HDFs by combining noble gas systematics with d¹³C, N concentrations, and fluid inclusion compositions for 21 individual growth zones in 13 diamonds from the Finsch (n = 3), DeBeers Pool (n = 7), and Koffiefontein (n = 3) mines on the Kaapvaal Craton. C isotope compositions range from -2.8 to -8.6‰ and N contents vary between 268 and 867 at.ppm, except for one diamond with contents of <30 at.ppm N. Nine of the thirteen studied diamonds contained saline HDF inclusions, but the other four diamonds had carbonatitic or silicic HDF inclusions. Carbonatitic and silicic HDFs yielded low He concentrations, R/Ra (³He/4Hesample/³He/4Heair) values of 3.2–6.7, and low 4°Ar/³6Ar ratios of 390–1940. Noble gas characteristics of carbonatitic-silicic HDFs appear consistent with a subducted sediment origin and interaction with eclogite. Saline HDFs are characterised by high He concentrations, with R/Ra mostly between 3.9 and 5.7, and a wide range in 4°Ar/³6Ar ratios (389–30,200). The saline HDFs likely originated from subducted oceanic crust with low He but moderate Ar contents. Subsequent interaction of these saline HDFs with mantle peridotite could explain the increase in He concentrations and mantle-like He isotope composition, with the range in low to high 4°Ar/³6Ar ratios dependent on the initial ³6Ar content and extent of lithosphere interaction. The observed negative correlation between 4He contents and R/Ra values in saline HDFs indicates significant in situ radiogenic 4He production. Noble gas geochemistry of fluid inclusions in South African diamonds: implications for the origin of diamond-forming fluids.
DS201906-1354
2019
Honda, M.Timmerman, S., Krebs, M.Y., Pearson, D.G., Honda, M.Diamond forming media through time - trace element and noble gas systematics of diamonds formed over 3 billion years of Earth's history.Geochimica et Cosmochimica Acta, in press available 29p.Africa, South Africa, Botswanadeposit - Koffiefontein, Letlhakane, Orapa, Finsch, De Beers Pool

Abstract: Ten individual gem-quality monocrystalline diamonds of known peridotite/eclogite paragenesis from Southern Africa (Koffiefontein, Letlhakane, Orapa) were studied for trace element concentrations and He and Ar abundances and isotopic compositions. In addition, two samples, consisting of pooled fragments of gem-quality peridotitic diamonds from Finsch and DeBeers Pool respectively, were analysed for noble gases. Previous studies (Richardson et al., 1984; Pearson et al., 1998; Gress et al., 2017; Timmerman et al., 2017) provided age constraints of 0.09, 1.0-1.1, 1.7, 2.3, and 3.2-3.4?Ga on mineral inclusions in the studied diamonds, allowing us to study trace elements and noble gases over 3 Gyr of geological time. Concentrations of trace elements in the diamonds are very low - a few hundred ppt to several tens of ppbs - and are likely dependent on the amount of sub-micron inclusions present. Trace element patterns and trace element/3He ratios of the studied monocrystalline diamonds are similar to those in fibrous diamonds, suggesting that trace elements and stable noble gas isotopes reside within the same locations in diamond and track the same processes that are reflected in the trace element patterns. We cannot discern any temporal differences in these geochemical tracers, suggesting that the processes generating them have been occurring over at least the past 2.3?Ga. 3He/4He ratios decrease and 4He and 40Ar* contents increase with increasing age of peridotitic and some eclogitic diamonds, showing the importance of in-situ radiogenic 4He and 40Ar ingrowth by the decay of U-Th-Sm and K respectively. For most gem-quality monocrystalline diamonds, uncertainties in the 3He/4He evolution of the continental lithospheric mantle combined with large analytical uncertainties and possible spatial variability in U-Th-Sm concentrations limit our ability to provide estimates of diamond formation ages using 4He ingrowth. However, the limited observed 4He ingrowth (low U?+?Th/3He) together with a R/Ra value of 5.3 for peridotitic diamond K306 is comparable to the present-day sub-continental lithospheric mantle value and supports the young diamond formation age found by Re-Os dating of sulphides in the same diamond by Pearson et al. (1998). After correction for in-situ radiogenic 4He produced since diamond formation a large variation in 3He/4He remains in ~1?Ga old eclogitic diamonds that is suggested to result from the variable influence of subducted altered oceanic crust that has low 3He/4He. Hence, the 3He/4He isotope tracer supports an origin of the diamond-forming fluids from recycled oceanic crust for eclogitic diamonds, as indicated by other geochemical proxies.
DS201906-1355
2019
Honda, M.Timmerman, S., Yeow, H., Honda, M., Howell, D., Jaques, A.L., Krebs, M.Y., Woodland, S., Pearson, D.G., Avila, J.N., Ireland, T.R.U-Th/He systematics of fluid rich 'fibrous' diamonds - evidence for pre- and syn-kimberlite eruption ages.Chemical Geology, Vol. 515, pp. 22-36.Africa, Democratic Republic of Congo, Botswanadeposit - Jwaneng

Abstract: The physical characteristics and impermeability of diamonds allow them to retain radiogenic 4He produced in-situ from radioactive decay of U, Th and Sm. This study investigates the U-Th/He systematics of fibrous diamonds and provides a first step in quantification of the uncertainties associated with determining the in-situ produced radiogenic 4He concentration. Factors determining the total amount of measured helium in a diamond are the initial trapped 4He, the in-situ produced radiogenic 4He, a-implantation, a-ejection, diffusion, and cosmogenic 3He production. Alpha implantation is negligible, and diffusion is slow, but the cosmogenic 3He component can be significant for alluvial diamonds as the recovery depth is unknown. Therefore, samples were grouped based on similar major and trace element compositions to determine possible genetically related samples. A correlation between the 4He and U-Th concentrations approximates the initial 4He concentration at the axis-intersect and age as the slope. In this study, the corrections were applied to eight fibrous cubic diamonds from the Democratic Republic of the Congo and two diamonds from the Jwaneng kimberlite in Botswana. A correlation exists between the 4He and U-Th concentrations of the group ZRC2, 3, and 6, and of the group CNG2, 3, and 4 and both correlations deviate significantly from a 71?Ma kimberlite eruption isochron. The U-Th/He dating method appears a promising new approach to date metasomatic fluid events that result in fibrous diamond formation and this is the first evidence that some fibrous diamonds can be formed 10s to 100s Myr before the kimberlite eruption.
DS201908-1818
2019
Honda, M.Timmerman, S., Honda, M., Zhang, X., Jaques, A.L., Bulanova, G., Smith, C.B., Burnham, A.D.Contrasting noble gas compositions of peridotitic and eclogitic monocrystalline diamonds from the Argyle lamproite, Western Australia.Lithos, Vol. 344-345, pp. 193-206.Australiadeposit - Argyle

Abstract: He-Ne-Ar compositions were determined in diamonds from the Argyle lamproite, Western Australia, to assess whether subducted material affects the noble gas budget and composition of stable old sub-continental lithospheric mantle (SCLM). Twenty diamonds (both peridotitic and eclogitic) were characterized for their carbon isotopic compositions and N abundance and aggregation from which 10 eclogitic growth zones and 5 peridotitic growth zones were analysed for their He-Ne-Ar compositions. The eclogitic diamonds have d13C values of -4.7 to -16.6‰ indicating a subduction signature, whereas the peridotitic diamonds have mantle-like compositions of -4.0 to -7.8‰. Mantle residence temperatures based on N-in-diamond thermometry showed that the eclogitic diamonds were mainly formed at 1260-1270?°C or above 1300?°C near the base of the lithosphere, whereas the peridotitic diamonds generally formed at lower temperatures (mostly 1135-1230?°C). A noble gas subduction signature is present to various extents in the eclogitic diamonds and is inferred from a hyperbolic mixing relationship between R/Ra and 4He and d13C values concentrations with a predominance of low R/Ra values (<0.5; R/Ra?=?3He/4Hesample/3He/4Heair). In addition, low 40Ar/4He and 40Ar/36Ar ratios, high nucleogenic 21Ne/4He and low 3He/22Ne ratios are characteristic of subducted material and were found in the eclogitic diamonds. The peridotitic diamonds show generally higher R/Ra values (median 1.1?±?1.1) and lower 4He/40Ar ratios compared to eclogitic diamonds (median 0.1?±?0.8 R/Ra; with 7/10 samples having an average of 0.13?±?0.14 R/Ra). The studied peridotitic diamond growth zones showed a negative correlation between R/Ra and 4He concentrations over 2 orders of magnitude and limited variation in 3He, that can be largely explained by radiogenic 4He ingrowth. At low 4He concentrations the R/Ra value is around 2.8 for both paragenesis of diamonds and is significantly lower than present-day SCLM values, suggesting (1) a more radiogenic helium isotope composition beneath the Halls Creek Orogen than those for typical SCLM from other cratons and/or (2) that the peridotitic diamonds are formed from fluids that also had a subduction input. The high mantle residence temperature and low R/Ra value in the core and low temperature and higher R/Ra value in the rim of a single peridotitic diamond indicate multiple growth events and that part of the lherzolitic diamond population may be genetically related to the eclogitic diamonds. Combining the diamond mantle residence temperatures with noble gas compositions shows that noble gas subduction signatures are present at the base of the lithosphere below 180?km depth beneath Argyle and that fluid migration and interaction with the SCLM occurred over scales of at least 15?km, between 180 and 165?km depth.
DS201909-2098
2019
Honda, M.Timmerman, S., Honda, M., Burnham, A.D., Amelin, Y., Woodland, S., Pearson, D.G., Jaques, A.L., Le Losq, C., Bennett, V.C., Bulanova, G.P., Smith, C.B., Harris, J.W., Tohver, E.Primordial and recycled helium isotope signatures in the mantle transition zone. Science, Vol. 365, 6454, pp. 692-694.Mantlediamond genesis

Abstract: Isotope compositions of basalts provide information about the chemical reservoirs in Earth’s interior and play a critical role in defining models of Earth’s structure. However, the helium isotope signature of the mantle below depths of a few hundred kilometers has been difficult to measure directly. This information is a vital baseline for understanding helium isotopes in erupted basalts. We measured He-Sr-Pb isotope ratios in superdeep diamond fluid inclusions from the transition zone (depth of 410 to 660 kilometers) unaffected by degassing and shallow crustal contamination. We found extreme He-C-Pb-Sr isotope variability, with high 3He/4He ratios related to higher helium concentrations. This indicates that a less degassed, high-3He/4He deep mantle source infiltrates the transition zone, where it interacts with recycled material, creating the diverse compositions recorded in ocean island basalts.
DS1990-0717
1990
Honda, S.Honda, S., Yuen, D.A.Mantle convection with moving heat-source anomalies:geophysical and geochemical implicationsEarth and Planetary Science Letters, Vol. 96, pp. 349-366GlobalMantle, Heat flow -geochemistry/geophysics
DS1991-1001
1991
Honda, S.Liu, M., Yuen, D.A., Zhao, W., Honda, S.Development of diapiric structures in the Upper mantle due to phasetransitionsScience, Vol. 252, June 24, pp. 1836-1839GlobalHot spot, Mantle
DS1993-0696
1993
Honda, S.Honda, S., Yuen, D.A., Balachandar, S., Reuteler, D.Three-dimensional instabilities of mantle convection with multiple phasetransitionsScience, Vol. 259, February 26, pp. 1308-1311MantlePlumes, Tectonics
DS1996-0647
1996
Honda, S.Honda, S., Iwase, Y.Comparison of the dynamic and parameterized models of mantle convection including core cooling.Earth and Planetary Science Letters, Vol. 139, pp. 133-145.MantleConvection, Core, model
DS1997-0517
1997
Honda, S.Honda, S.A possible role of weak zone at plate margin on secular mantle coolingGeophy. Res. Letters, Vol. 24, No. 22, Nov. 15, pp. 2861-4.MantleTectonics
DS1997-0834
1997
Honda, S.Nakakuki, T., Yuen, D.A., Honda, S.The interaction of plumes with the transition zone under continents andoceans.Earth and Planetary Letters, Vol. 146, No. 3/4. Feb 1, pp. 379-392.MantlePlumes
DS200512-0445
2005
Honda, S.Honda, S., Yoshida, T.Effects of oblique subduction on the 3-D pattern of small scale convection within the mantle wedge.Geophysical Research Letters, Vol. 32, 13, July 16, L13307MantleGeophysics - seismics, subduction
DS200912-0311
2009
Honda, S.Honda, S.Numerical simulations of mantle flow around slab edges.Earth and Planetary Science Letters, Vol. 277, 1-2, pp. 112-122.MantleSubduction
DS201012-0285
2010
Honda, S.Honda, S., Gerya, T., Zhu, G.A simple three dimensional model of thermo-chemical convection in the mantle wedge.Earth and Planetary Science Letters, Vol. 290, 3-4, pp. 311-316.MantleGeothermometry
DS201212-0808
2012
Honda, S.Yoshida, M., Tajima, F., Honda, S., Morishige, M.The 3D numerical modeling of subduction dynamics: plate stagnation and segmentation, and crustal advection in the wet mantle transition zone.Journal of Geophysical Research, Vol. 117, B4, B0104MantleSubduction
DS2003-0599
2003
Hondan, M.Hondan, M., Nutman, A.P., Bennett, V.C.Xenon composition of magmatic zircons in 3.64 and 3.81 Ga meta-granitoids fromEarth and Planetary Science Letters, Vol. 207, 1-4, Feb. 28, pp. 69-82.GreenlandGeochemistry - noble gases
DS1997-0518
1997
Hone, I.G.Hone, I.G., Milligan, P.R., Mitchell, J.N., Horsfall, K.R.Australian national airborne geophysical databaseAgso Journal, Australian Geology And Geophysics, Vol. 17, No. 2, pp. 11-22AustraliaGeophysics - airborne
DS1920-0186
1924
Honess, A.P.Honess, A.P., Graeber, C.K.A New Occurrence of an Igneous Dike in Southwestern Pennsylvania.American Journal of Science, SER. 5, Vol. 7, PP. 313-315.United States, Appalachia, PennsylvaniaDixonville, Indiana County, Related Rocks, Geology
DS1920-0284
1926
Honess, A.P.Honess, A.P., Graeber, C.K.Petrography of the Mica Peridotite Dike at Dixonville, Pennsylvania #2American Journal of Science, SER. 5, Vol. 12, PP. 484-494.United States, Appalachia, PennsylvaniaPetrography, Related Rocks
DS1920-0285
1926
Honess, A.P.Honess, A.P., Graeber, C.K.Petrography of the Mica Peridotite Dike at Dixonville, Pennsylvania #1Pennsylvania State Coll. Min. Met. Exploration Bulletin., No. 2, 16P.United States, Appalachia, PennsylvaniaRelated Rocks, Petrography
DS202006-0922
2020
Hong, L.Hong, L., Znag,, M.Object oriented multiscale deep features for hyperspectral image classification. (Not specific to diamonds)International Journal of Remote Sensing, Vol. 41, 14, pp. 5549-5572.Globalhyperspectral

Abstract: The classification of hyperspectral images (HSIs) is one of the most popular topics in the remote sensing community. Numerous feature extraction methods have been proposed to improve the classification accuracy of HSIs. Recently, deep features extracted by convolution neural network (CNN) have been introduced into the classification process of HSIs. Due to the nonlinear and invariant advantages of the features, CNN methods provide a powerful tool for representing geographic objects and classifying HSIs. However, traditional deep features only extracted at pixel-level and often neglect multiscale characteristics of geographic objects. In this study, a new deep feature extraction method is proposed, which takes advantage of multi-scale object analysis and the CNN model. Firstly, multiscale image objects are obtained by the multiscale segmentation algorithm and multiscale low-level features of objects are extracted. Secondly, the CNN is devoted to obtain deep features from low-level object features at each scale, respectively. Thirdly, the obtained deep features at all scales are stacked and fed to one fully connected layer to extract the multiscale deep learning features for classification. Finally, the logistic regression classifier is applied to hyperspectral image (HSI) classification based on object-oriented multiscale deep features. The proposed method was carried out on three widely used hyperspectral data sets: University of Pavia, Salinas, and Washington DC. The results reveal that the proposed method provides better results than other state-of-the-art methods.
DS200712-0005
2007
Hong, X.Ai,Y., Chen, Q-F., Zeng, F., Hong, X., Ye, W.The crust and upper mantle structure beneath southeastern China.Earth and Planetary Science Letters, Vol. 260, 3-4, pp. 549-563.ChinaTectonics
DS200412-0848
2004
Hong Fu, Z.Hong Fu, Z., Min, S.,Mei Fu, Z., Wei Ming, F., Zin Hua, Z., Ming Guo, Z.Highly heterogeneous Late Mesozoic lithospheric mantle beneath the North Chin a Craton: evidence from Sr Nd Pb isotopic systematiGeological Magazine, Vol. 141, 1, pp. 55-62.ChinaGeochronology
DS1989-0656
1989
Hong Kong StandardHong Kong StandardSumitomo's synthetic diamondsHong Kong Standard, August 31, vetted from Indiaqua, No. 54, 1989/III p. 63GlobalNews item, Diamond synthesis
DS1991-1180
1991
Hongin, F.Mon, R., Hongin, F.The structure of the Precambrian and Lower Paleozoic basement of the central Andes between 22 and 22 latsGeologische Rundschau, Vol. 80, No. 3, pp. 745-758AndesStructure, Tectonics
DS1996-0648
1996
Hongn, F.Hongn, F., Mon, R., Cuevas, J., Tubia, J-M.Zones of cisaillement caledonieenes a haut temperature dans la QuebradaBarranquilla: donnees structurales..C.r. Academy Of Science Paris, Vol. 323, 11a, pp. 809-815Argentina, Eastern PunaTectonics, high temperature overthrust, Metamorphism, evolution
DS201509-0399
2015
Hongsresawat, S.Hongsresawat, S., Panning, M.P., Russo, R.M., Foster, D.A., Monteiller, V., Chevrot, S.USArray shear wave splitting shows seismic anisotropy from both lithosphere and asthenosphere.Geology, Vol. 43, 8, pp. 667-670.United StatesSeismic -anisotropy

Abstract: North America provides an important test for assessing the coupling of large continents with heterogeneous Archean- to Cenozoic-aged lithospheric provinces to the mantle flow. We use the unprecedented spatial coverage of the USArray seismic network to obtain an extensive and consistent data set of shear wave splitting intensity measurements at 1436 stations. Overall, the measurements are consistent with simple shear deformation in the asthenosphere due to viscous coupling to the overriding lithosphere. The fast directions agree with the absolute plate motion direction with a mean difference of 2° with 27° standard deviation. There are, however, deviations from this simple pattern, including a band along the Rocky Mountain front, indicative of flow complication due to gradients in lithospheric thickness, and variations in amplitude through the central United States, which can be explained through varying contributions of lithospheric anisotropy. Thus, seismic anisotropy may be sourced in both the asthenosphere and lithosphere, and variations in splitting intensity are due to lithospheric anisotropy developed during deformation over long time scales.
DS200412-1817
2003
Hongyang, L.Shuyin, N., Quanlin, H., Zengqian, H., Aiqun, S., Baode, W., Hongyang, L., Chuanshi, X.Cascaded evolution of mantle plumes and metallogenesis of core and mantle derived elements.Acta Geologica Sinica, Vol. 77, 4, pp. 522-536.MantleMetallogeny
DS2002-0933
2002
Honig, M.Leibecker, J., Getzmeier, A., Honig, M., Kuras, O., Soyer, W.Evidence of electrical anisotropic structures in the lower crust and the upper mantleEarth and Planetary Science Letters, Vol. 202, 2, pp. 289-302.EuropeGeophysics - seismics
DS1975-0888
1978
Honig, R.H.Wagner, G.H., Honig, R.H., Jones, M.D.Geochemistry of a Carbonatite in Montgomery County, ArkansawArkansaw Academy of Science Proceedings, Vol. 32, PP. 93-94.United States, Gulf Coast, Arkansas, PennsylvaniaGeochemistry
DS1990-0437
1990
Honigstein, A.Dvorachek, M., Rosenfeld, A., Honigstein, A.Contamination of geological samples in scanning electron microscopyNeues Jahrb, No. 12, pp. 707-716GlobalMicroscopy, Review
DS201904-0745
2019
Honing, D.Honing, D., Tosi, N., Hansen-Goos, H., Spohn, T.Bifurcation in the growth of continental crust. (Water-land ratio)Physics of the Earth and Planetary Interiors, Vol. 287, pp. 37-50.Mantleplate tectonics

Abstract: Is the present-day water-land ratio a necessary outcome of the evolution of plate tectonic planets with a similar age, volume, mass, and total water inventory as the Earth? This would be the case - largely independent of initial conditions - if Earth’s present-day continental volume were at a stable unique equilibrium with strong self-regulating mechanisms of continental growth steering the evolution to this state. In this paper, we question this conjecture. Instead we suggest that positive feedbacks in the plate tectonics model of continental production and erosion may dominate and show that such a model can explain the history of continental growth. We investigate the main mechanisms that contribute to the growth of the volume of the continental crust. In particular, we analyze the effect of the oceanic plate speed, depending on the area and thickness of thermally insulating continents, on production and erosion mechanisms. Effects that cause larger continental production rates for larger values of continental volume are positive feedbacks. In contrast, negative feedbacks act to stabilize the continental volume. They are provided by the increase of the rate of surface erosion, subduction erosion, and crustal delamination with the continental volume. We systematically analyze the strengths of positive and negative feedback contributions to the growth of the continental crust. Although the strengths of some feedbacks depend on poorly known parameters, we conclude that a net predominance of positive feedbacks is plausible. We explore the effect of the combined feedback strength on the feasibility of modeling the observed small positive net continental growth rate over the past 2-3 billion years. We show that a model with dominating positive feedbacks can readily explain this observation in spite of the cooling of the Earth’s mantle acting to reduce the continental production rate. In contrast, explaining this observation using a model with dominating negative feedbacks would require the continental erosion and production rates to both have the same or a sufficiently similar functional dependence on the thermal state of the mantle, which appears unreasonable considering erosion to be largely dominated by the surface relief and weathering. The suggested scenario of dominating positive feedbacks implies that the present volume of the continental crust and its evolution are strongly determined by initial conditions. Therefore, exoplanets with Earth-like masses and total water inventories may substantially differ from the Earth with respect to their relative land/surface ratios and their habitability.
DS200812-1148
2008
Honkura, Y.Takahashi, F., Tsunakawa, H., Matsushima, M., Mochizuki, N., Honkura, Y.Effects of thermally homogeneous structure in the lowermost mantle on the geomagnetic field strength.Earth and Planetary Science Letters, Vol. 272, 3-4, pp. 738-746.MantleGeothermometry
DS202009-1661
2020
Honn, D.K.Sjoqvist, A.S.L., Zack, T., Honn, D.K., Baxter, E.F.Modification of a rare-earth element deposit by low temperature partial melting during metamorphic overprinting: Norra Karr alkaline complex, southern Sweden.Chemical Geology, Vol. 545, 13p. PdfEurope, SwedenREE

Abstract: Rare-earth elements play a crucial role in modern technologies and are necessary for a transition to a green economy. Potentially economic deposits of these elements are typically hosted in minerals such as monazite, bastnäsite, and eudialyte (a complex Na-Ca-Fe-Zr silicate mineral with Cl), making these prime targets for geological research. Globally, rare-earth mineral deposits commonly show evidence of polyphase development and mineralisation processes, which need to be better understood to improve exploration strategies. The Norra Kärr alkaline complex (Sweden) contains a globally significant deposit of rare-earth elements, hosted in the mineral eudialyte. In this study, we focussed on eudialyte crystals in undeformed, cross-cutting pegmatoid veins from Norra Kärr. In order to determine their age, we refined an established micromilling method to enable sampling of minerals rich in rare-earth elements for precise analysis of major and trace elements, Nd isotope ratios, and Sm-Nd geochronology down to a scale of <200?µm. Mineral samples were subjected to detailed textural and chemical characterisation by backscattered electron imaging and laser ablation inductively coupled plasma mass spectrometry, by which precise and accurate Sm/Nd ratios were determined to steer subsequent micromill sampling for small-aliquot Sm-Nd isotope analysis by isotope dilution thermal ionisation mass spectrometry. Given enough internal spread in Sm/Nd ratios, reliable Sm-Nd isochrons can be derived from discrete textural domains within a single crystal. This provided an age of 1.144?±?0.053?Ga (95% confidence); approximately 350?million?years younger than the magmatic intrusion of the alkaline complex (ca. 1.49?Ga). Primary compositional sector and oscillatory zoning in these eudialyte crystals shows core-to-rim enrichment in rare-earth elements and significant fractionation of K/Rb, Y/Ho, Zr/Hf, and Nb/Ta, which we attribute to crystallisation under influence of complexing ligands in a confined volume. We argue that these mineralised pegmatoid veins formed by low-temperature (<550?°C) partial melting of the agpaitic host rock during an early Sveconorwegian (Grenvillian) metamorphic overprinting event. Given the challenge of directly dating rare-earth ore minerals by conventional methods, modification of rare-earth mineral deposits may be more widespread than already assumed, which shows the importance of investigations that date the rare-earth minerals themselves.
DS1920-0235
1925
Honnold, W.L.Honnold, W.L.Diamond Mining in South Africa. #4Min. Met. (u.s.), Vol. 6, PP. 324-331.South AfricaAlluvial Diamond Placers
DS2002-0293
2002
HoodClements, B.P., Skelton, McCandless, HoodThe Buffalo Head Hills kimberlite province, AlbertaGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.22., p.22.AlbertaRegional geology - brief
DS2002-0294
2002
HoodClements, B.P., Skelton, McCandless, HoodThe Buffalo Head Hills kimberlite province, AlbertaGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.22., p.22.AlbertaRegional geology - brief
DS1998-0216
1998
Hood, C.T.Carlson, S.M., Hillier, W.D., Hood, C.T., Pryde, R.P.The Buffalo Hills kimberlite province, north central Alberta, Canada7th International Kimberlite Conference Abstract, pp. 138-140.AlbertaKimberlites, Petrography
DS2003-0113
2003
Hood, C.T.Birkett, T.C., McCandelss, T.E., Hood, C.T.Petrology of the Renard igneous bodies: host rocks for diamond in the northern Otish8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractQuebec, Otish MountainsKimberlite petrogenesis
DS2003-0149
2003
Hood, C.T.Boyer, L.P., Hood, C.T., McCandless, T.E., Skelton, D.N., Tosdal, R.D.Volcanology of the Buffalo Hills kimberlites, Alberta, Canada8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractAlbertaKimberlite geology and economics, Volcanism
DS2003-0150
2003
Hood, C.T.Boyer, L.P., Hood, C.T., McCandless, T.E., Skelton, D.N., Tosdal, R.M.Volcaniclastic kimberlites of the Buffalo Head Hills, Alberta, CanadaGeological Association of Canada Annual Meeting, Abstract onlyAlbertaPetrology
DS2003-0600
2003
Hood, C.T.Hood, C.T., McCandless, T.E.Systematic variations in xenocryst mineral composition at the Province scale, Buffalo8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, AbstractAlbertaDiamond exploration - mineralogy, Deposit - Buffalo Hills
DS200412-0156
2003
Hood, C.T.Birkett, T.C., McCandelss, T.E., Hood, C.T.Petrology of the Renard igneous bodies: host rocks for diamond in the northern Otish Mountains Region, Quebec.8 IKC Program, Session 7, AbstractCanada, Quebec, Otish MountainsKimberlite petrogenesis
DS200412-0198
2003
Hood, C.T.Boyer, L.P., Hood, C.T., McCandless, T.E., Skelton, D.N., Tosdal, R.M.Volcaniclastic kimberlites of the Buffalo Head Hills, Alberta, Canada.Geological Association of Canada Annual Meeting, Abstract onlyCanada, AlbertaPetrology
DS200412-0849
2003
Hood, C.T.Hood, C.T., McCandless, T.E.Systematic variations in xenocryst mineral composition at the Province scale, Buffalo Hills kimberlites, Alberta Canada.8 IKC Program, Session 8, AbstractCanada, AlbertaDiamond exploration - mineralogy Deposit - Buffalo Hills
DS200412-0850
2004
Hood, C.T.S.Hood, C.T.S., McCandless, T.E.Systematic variations in xenocryst mineral composition at the province scale, Buffalo Hills kimberlites, Alberta Canada.Lithos, Vol. 77, 1-4, Sept. pp. 733-747.Canada, AlbertaMineral chemistry, Proterozoic mantle, pyrope, chromian
DS1991-0728
1991
Hood, P.Hood, P., Webster, S.Research workshop on airborne geophysicsThe Leading Edge, Vol. 10, No. 11, November pp. 83-87GlobalGeophysics -airborne, Overview -current
DS200712-0451
2007
Hood, P.Hood, P.History of aeromagnetic surveying in Canada.The Leading Edge, November pp. 1384-1392.TechnologyGeophysics - history, overview
DS1985-0027
1985
Hood, P.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
DS1989-0657
1989
Hood, P.J.Hood, P.J., Teskey, D.J.Aeromagnetic gradiometer program of the Geological Survey of CanadaGeophysics, Vol. 54, No. 8, August pp. 1012-1222CanadaGeophysics, Gradiometer
DS1993-1585
1993
Hood, P.J.Teskey, D.J., Hood, P.J., et al.The aeromagnetic survey program of the Geological Survey of Canada:contribution to regional geological mapping and mineral explorationCanadian Journal of Earth Sciences, Vol. 30, No. 2, February pp. 243-260CanadaGeophysics -aeromagnetics, Overview and applications
DS201012-0286
2010
Hood, W.C.Hood, W.C., Lee, J.E.Diamond exploration at Wekusko Lake.Manitoba Mining Review, pp. 29-31.Canada, ManitobaDikes
DS1993-0697
1993
Hoogerduijn Strating, E.H.Hoogerduijn Strating, E.H., et al.Subsolidus emplacement of mantle peridotites during incipient Oceanic rifting and opening Mesozoic...Journal of Petrology, Vol. 34, No. 5, pp. 901-27.ItalyPeridotite, Voltri Massif
DS1997-0519
1997
Hoogewerff, J.A.Hoogewerff, J.A., et al.Uranium series, Strontium, neodymium, lead isotope and trace element systematics across an active island arc continent zoneGeochimica et Cosmochimica Acta, Vol. 61, No. 5, March pp. 1057-72GlobalGeochemistry, Slab-wedge interface, subduction
DS1990-1071
1990
Hook, S.C.Mount, V.S., Suppe, J., Hook, S.C.A foreward modeling strategy for balancing cross sectionsAmerican Association of Petroleum Geologists (AAPG) Bulletin, Vol. 74, No. 5, pp. 521-531GlobalStructure, Cross sections
DS201212-0270
2012
Hooke, J.Guneralp, I., Abad, J.D., Zolezzi, G., Hooke, J.Advances and challenges in meandering channels research.Geomorphology, Vol. 163-164, pp. 1-9.TechnologyMeandering channels - issue (not specific to diamonds)
DS2003-0601
2003
Hooke, R.L.Hooke, R.L.Time constant for equilibration of erosion with tectonic upliftGeology, Vol. 31, 7, July, pp. 621-4.GlobalGeomorphology
DS200412-0851
2003
Hooke, R.L.Hooke, R.L.Time constant for equilibration of erosion with tectonic uplift.Geology, Vol. 31, 7, July, pp. 621-4.TechnologyGeomorphology
DS1989-0658
1989
Hook-Shelton, S.Hook-Shelton, S.Insider trading monitor: an essential piece of the investment puzzleDatabase, Vol. 12, No. 2, April pp. 69-71. Database # 17956GlobalComputer, Program - Insider trading
DS201605-0866
2016
Hooman, M.Marx, W., Hooman, M.Block cave mining operations - venillation challenges and opportunities.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 143-152.TechnologyMining - applied
DS201212-0305
2012
Hooper, A.Hooper, A.Volcanology: a volcano's sharp intake of breath.Nature Geoscience, Vol. 5, 10, pp. 686-687.MantleVolcanism
DS1989-0659
1989
Hooper, D.G.Hooper, D.G.How did the flow-through mineral funds perform?Prospectors and Developers Association of Canada (PDAC) Digest Autumn, pp. 10, 11, 15. Database # 18221CanadaFlow through, Economics
DS1992-0456
1992
Hooper, G.B.Ferguson, G.A., Hooper, G.B.Mining design software - a critical reviewTransactions of the Institute of Mining and Metallurgy (IMM), Vol. 101, Sept-Dec, pp. A 127-A134GlobalComputer, Mining software
DS1989-0416
1989
Hooper, P.R.Fan, Q., Hooper, P.R.The mineral chemistry of ultramafic xenoliths of Eastern China:implications for Upper mantle composition and the paleogeothermsJournal of Petrology, Vol. 30, No. 5, October pp. 1117-1158ChinaMantle, Xenoliths -mineral chemis
DS1990-0718
1990
Hooper, P.R.Hooper, P.R.The timing of crustal extension and the eruption of continental floodbasaltsNature, Vol. 345, No. 6272, May 17, pp. 246-248GlobalBasalts, Continental crust
DS1987-0216
1987
Hooper, R.L.Foit, F.F., Hooper, R.L., Rosenberg, P.E.An unusual pyroxene, melilite and iron oxide mineral assemblage in a coalfire buchite from Buffalo WyomingAmerican Mineralogist, Vol. 72, No. 1-2, Jan-Feb. pp. 137-147WyomingUSA, Melilite
DS1995-0819
1995
Hoorn, C.Hoorn, C., Guerrero, J., Sarmiento, G.A., Lorente, M.A.Andean tectonics as a cause for changing drainage patterns in Miocene northern South America.Geology, Vol. 23, No. 3, March pp. 237-240.Guyana Shield, VenezuelaTectonics, Geomorphology
DS1999-0315
1999
Hoos, R.A.W.Hoos, R.A.W., Williams, W.S.Environmental management at BHP's Ekati diamond mine in the westernArctic.Mining in the Arctic, Udd and Keen editors, Balkema, pp. 63-70.Northwest TerritoriesMining - environmental, Deposit - Ekati
DS2000-0421
2000
Hoosen, Z.Hoosen, Z., Kurzlaukis, S., Kiviets, G.B., Fourie, L.F.New high Pressure precision ages from the Gideon and Maltahohe kimberlite fields, southern Namibia.Journal of African Earth Sciences, p. 31. abstract.NamibiaGeochronology - age determination, Deposit - Gibeon, Maltahohe
DS201509-0407
2014
Hoover, D.Karfunkel, J., Hoover, D., Fernandes, A.F., Sgarbi, G.M.C., Kambrock, K., Oliviera, G.D.Diamonds from the Coromandel area, west Minas Gerais State, Brazil: an update and new dat a on surface sources and origin.Brazil Journal of Geology, Vol. 44, 2, pp. 325-338.South America, Brazil, Minas GeraisDeposit - Coromandel

Abstract: Important diamond deposits southeast of Coromandel and the local geology have been studied in an attempt to understand what surface source provided the stones. River gravels of Pleistocene to Recent age from this region have supplied most of Brazil’s large diamonds over 100 ct. The upper cretaceous Capacete Formation of the Mata da Corda Group, composed of mafic volcanoclastic, pyroclastic and epiclastic material, has been worked locally for diamonds, nevertheless considered non-economic. The authors present results of their study of a deactivated small mine, representing the first report with description and analyses of two gem diamonds washed from this material. Hundreds of kimberlites, discovered in the last half century in the region, are sterile or non-economic. We propose that the surface source of the diamonds is the Capacete “conglomerado”. The volume of this material is enormous representing a potential resource for large-scale mining. The authors suggest detailed studies of the volcanic facies of this unit focusing on the genesis, distribution and diamond content. As to the question concerning the origin of these diamondiferous pyroclastic rocks, the authors exclude the kimberlites and point towards the large Serra Negra and Salitre alkaline complexes which are considered the primary source for the pyroclastic units of the Mata da Corda Group. They propose that early eruptive phases of this alkaline complex brought diamonds from a mantle source to the surface, much as happens with traditional kimberlites, to explain the association of such huge carbonatite complexes and diamonds.
DS201509-0408
2015
Hoover, D.Karfunkel, J., Hoover, D., Fernandes, A.F., Sgarbi, G.M.C., Oliviera, G.D., Walde, D., Michelfelder, G.Surface source of Coromandel diamonds ( Minas Gerais State) Brazil and their possible origin from the Serra Negra/Salitre Supervolcano.Neues Jahrbuch fur Geologie und Palaontologie , Vol. 277, 2, pp. 237-250.South America, Brazil, Minas GeraisDeposit - Coromandel

Abstract: The origin of diamonds in the Coromandel area has been an enigma for many years, in spite of high investment in conventional and high tech prospecting methods by major mining companies for over half a century. The authors review the history, and then discuss the two principal hypotheses to explain the source of these alluvial diamonds. After mapping the headwater region of one of the richest alluvial diamond rivers, the Santo Antônio do Bonito River, they reject both principal hypotheses and conclude that the surficial source can be only the Upper Cretaceous Capacete Formation, composed of pyroclastics and epiclastics. Based on geophysical data from the literature, combined with field observations the authors suggest that the largest alkaline complex, situated within the diamond producing area, the Serra Negra/Salitre Complex has been the primary source for those pyroclastics of the Capacete Formation and the diamonds. The plugs of this complex are 15-30 times deeper than average kimberlites and other alkaline complexes in the region, and its excess of volume of the intrusive is three orders of magnitude larger than a typical kimberlite. With an intrusive volume of over 1000 km3 the complex is suggested to be a possible supervolcano. This explains the vast areal distribution of the pyroclastics and diamonds. This new hypothesis has advantages and disadvantages, some of them discussed in the paper and leading to the conclusion that further research is needed.
DS1983-0312
1983
Hoover, D.B.Hoover, D.B.The Gem Diamondmaster and the Thermal Properties of GemsGems And Gemology, Vol. 19, No. 2, SUMMER, PP. 77-86.GlobalTechnique, Diamond, Test
DS1992-0725
1992
Hoover, D.B.Hoover, D.B., Heran, W.D., Hill, P.L.The geophysical expression of selected mineral deposit modelsUnited States Geological Survey (USGS) Open File, No. 92-557, 140pUnited StatesGeophysics, Deposits
DS1994-0785
1994
Hoover, D.B.Hoover, D.B., Campbell, D.L.Geophysical model of diamond pipesUnited States Geological Survey (USGS) Open file, No. 94-0174, 36p. Diamond pipe 1p, p. 32.GlobalGeophysics, Diamond pipes
DS1994-1024
1994
Hoover, D.B.Leinz, R.W., Hoover, D.B.Ideal CHIM with the newly developed NEOCHIM electrodeExlore, No. 83, pp. 10-15GlobalGeochemistry, Mineral deposit technology
DS2001-0177
2001
Hoover, D.B.Chaves, M.L., Karfunkel, J., Hoppe, A., Hoover, D.B.Diamonds from the Espinaco Range and their redistribution through the geologic record.Journal of South American Earth Sciences, Vol. 14, No. 3, pp. 277-89.Brazil, Minas GeraisDiamond - morphology, Alluvials, genesis
DS200912-0312
2009
Hoover, D.B.Hoover, D.B., Karfunkel, J.Large Brazilian diamonds.Australian Gemmologist, Vol. 23, 10, pp. 1-South America, BrazilDiamond notable
DS201212-0306
2012
Hoover, D.B.Hoover, D.B.Determining garnet composition from magnetic susceptibility and other properties.Gems & Gemology, Vol. 47, 4, pp. 272-285.TechnologyGarnet mineralogy
DS201412-0244
2014
Hoover, D.B.Fernandes, A.F., Karfunkel, J., Hoover, D.B., Sgarbi, G.N.C., Walde, D., Gomes, J., Kambrock, K.O garimpo Canastrel, Coromandel-MG: ocorrencia de diamante no conglomerado cretaceo do grupo Mat a de Corda.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractSouth America, Brazil, Minas GeraisDeposit - Coromandel
DS201412-0442
2014
Hoover, D.B.Karfunkel, J., Hoover, D.B., Fernandes, A.F., Sgarbi, G.N.C., Kambrock, K., Walde, D., Michelfelder, G.Origin of diamonds southeast of Coromandel ( Minas Gerais Brazil): a different hypothesis.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 5p. AbstractSouth America, Brazil, Minas GeraisDeposit - Coromandel
DS201501-0008
2014
Hoover, D.B.Fernandes, A.F., Karfunkel, J., Hoover, D.B., Sgarbi, P.B.De Al., Sgarbo, G.N.C., Oliveira, G.D., Gomes, J.C.de S.P., Kambrock, K.The basal conglomerate of the Capacete Formation ( Mat a da Corda Group) and its relation to diamond distributions in Coromandel, Minas Gerais State, Brazil.Brazil Journal of Geology, Vol. 44, 1, pp. 91-103.South America, BrazilCoromandel district

Abstract: The diamond bearing district of Coromandel is located in the northwestern part of Minas Gerais, within the Alto Paranaíba Arch, famous for the discovery of most of Brazil's large diamonds above 100 ct. Detailed mapping, aimed at characterizing the Mata da Corda Group of Upper Cretaceous age of Coromandel, has been carried out. This Group was divided into the Patos Formation, composed of kimberlitic and kamafugitic rocks, and the Capacete Formation, presented by conglomerates, pyroclastic rocks, arenite and tuffs. Exposures of the latter Formation have been studied in detail at the small abandoned mine called Canastrel, as well as in the headwater of Santo Antônio do Bonito River. The results have been compared to studies of the kimberlite bodies in the nearby Douradinho River. Kimberlite indicator minerals from these localities show the same compositional trend. Moreover, in the basal conglomerate of the Garimpo Canastrel two diamonds diamonds have been recovered and described. The Garimpo Wilson, situated in the headwater of the river Santo Antônio do Bonito in paleo-alluvium, is composed of material exclusively derived from the erosion of the Capacete Formation and Precambrian (sterile) Canastra quartzites and schists. These detailed investigations suggest that the basal conglomerates of the Capacete Formation represent the main source rock of the alluvial diamond deposits in the Coromandel region.
DS201510-1788
2015
Hoover, D.B.Michelfelder, G.S., Karfunkel, J., Fernandes, A.F., Sgarbi, N.C., Hoover, D.B., Krambrock, K., Walde, D.Surface source of Coromandel diamonds ( Minas Gerais State), Brazil) and their possible origin from the Serra Negra/Salitre supervolcano.GSA Annual Meeting, Paper 300-1, 1p. Abstract only BoothSouth America, Brazil, Minas GeraisDeposit - Coromandel

Abstract: The origin of diamonds in the Coromandel area has been an enigma for many years, in spite of high investment in conventional and high tech prospecting methods by major mining companies for over half a century. The authors review the history, and then discuss the two principal hypotheses to explain the source of these alluvial diamonds. After mapping the headwater region of one of the richest alluvial diamond rivers, the Santo Antônio do Bonito River, they reject both principal hypotheses and conclude that the surficial source can be only the Upper Cretaceous Capacete Formation, composed of pyroclastics and epiclastics. Based on geophysical data from the literature, combined with field observations the authors suggest that the largest alkaline complex, situated within the diamond producing area, the Serra Negra/Salitre Complex has been the primary source for those pyroclastics of the Capacete Formation and the diamonds. The plugs of this complex are 15-30 times deeper than average kimberlites and other alkaline complexes in the region, and its excess of volume of the intrusive is three orders of magnitude larger than a typical kimberlite. With an intrusive volume of over 1000 km3 the complex is suggested to be a possible supervolcano. This explains the vast areal distribution of the pyroclastics and diamonds. This new hypothesis has advantages and disadvantages, some of them discussed in the paper and leading to the conclusion that further research is needed.
DS201710-2233
2017
Hoover, D.B.Hoover, D.B., Karfunkel, J., Ribeiro, L.C.B., Michelfelder, G.., Moraes, R.A.V., Krambrock, K., Quintao, D., Walde, D.Diamonds of the Alto Paranaiba, Brazil: Nixon's prediction verified?The Australian Gemmologist, Vol. 26, 5&6, pp. 88-99.South America, Brazil, Minas Geraisdeposit - Alto Paranaiba

Abstract: The authors, in a paper in this journal in 2009, note a puzzle, that in spite of extensive exploration for diamonds by major producers in the Alto Paranaiba region of West Minas Gerais State, Brazil, no primary source, such as kimberlites, for the many diamonds produced since their discovery over 250 years has been found. To answer this puzzle we propose that the diamonds are present within a large extrusive volcanic unit probably derived from the Serra Negra alkaline-carbonatitic complex which comprises a super volcano. This origin fits with the 1995 prediction of Nixon on the future direction of diamona-exploration that extrusive units may contain very large volumes of ore, and that carbonatitic emplacement sources need to be considered. The authors argue, based on available evidence from geology and geophysics, that such an origin is compatible with the known data, but that much additional information is needed to substantiate these ideas. Diamonds of the Alto Paraniaba, Brazil: Nixon's prediction verified?
DS201809-2036
2018
Hoover, D.B.Hoover, D.B., Karfunkel, J., Walde, D., Moraes, R.A.V., Michelfelder, G., Henger, F.E., Ribeira, L.C., Krambock, K.The Alto Paranaiba region, Brazil: a continuing source for pink diamonds?The Australian Gemmologist, Vol. 26, 9-10, pp. 196-204.South America, Brazildeposit - Alto Paranaiba
DS202012-2219
2020
Hoover, W.F.Hoover, W.F., Page, F.Z., Schulze, D.J., Kitajima, K., Valley, J.W.Massive fluid influx beneath the Colorado Plateau ( USA) related to slab removal and diatreme emplacement: evidence from oxygen isotope zoning in eclogite xenoliths.Journal of Petrology, in press available, 52p. PdfUnited States, Colorado Plateaueclogite

Abstract: The Colorado Plateau has undergone as much as 1.8?km of uplift over the past 80?Ma, but never underwent the pervasive deformation common in the neighboring tectonic provinces of the western USA. To understand the source, timing and distribution of mantle hydration, and its role in plateau uplift, garnets from four eclogite xenoliths of the Moses Rock diatreme (Navajo Volcanic Field, Utah, USA) were analyzed in situ for d18O by secondary ion mass spectrometry. These garnets have the largest reported intra-crystalline oxygen isotope zoning to date in mantle-derived xenoliths with core-to-rim variations of as much as 3‰. All samples have core d18O values greater than that of the pristine mantle (~5.3‰, mantle garnet as derived from mantle zircon; Valley et al., 1998; Page et al., 2007) consistent with an altered upper oceanic crust protolith. Oxygen isotope ratios decrease from core to rim recording interaction with a low-d18O fluid at high temperature, likely derived from serpentinite in the foundering Farallon slab. All zoned samples converge at a d18O value of ~6‰, regardless of core composition, suggesting that fluid infiltration was widely distributed. Constraints on the timing of this fluid influx, relative to diatreme emplacement, can be gained from diffusion modeling of major element zoning in garnet. Modeling using best-estimates of peak metamorphic conditions (620ºC, 3.7?GPa) yield durations of?
DS2003-0626
2003
Hooyer, T.S.Iverson, N.R., Cohen, D., Hooyer, T.S., Fischer, U.H., Jackson, M., Moore, P.L.Effects of basal debris on glacier flowScience, No. 5629, July 4, pp. 81-83.GlobalGeomorphology
DS200412-0884
2003
Hooyer, T.S.Iverson, N.R., Cohen, D., Hooyer, T.S., Fischer, U.H., Jackson, M., Moore, P.L., Lappegard, G., Kohler, J.Effects of basal debris on glacier flow.Science, No. 5629, July 4, pp. 81-83.TechnologyGeomorphology
DS2001-0286
2001
HopeEaton, D., Ferguson, Jones, Hope, WuA geophysical shear sense indicator and the role of mantle lithosphere in transcurrent faulting.Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractNorthwest TerritoriesGeophysics, Great Slave Lake Shear Zone
DS2001-0487
2001
Hope, G.A.Hope, G.A., Woods, R., Munce, C.G.Raman microprobe mineral identificationMinerals Engineering, Vol. 14, No. 12, Dec. pp. 1565-77.GlobalMentions diamond, Microprobe mineralogy
DS1999-0187
1999
Hope, J.Eaton, D.W., Ross, G.M., Hope, J.The rise and fall of a cratonic arch; a regional seismic perspective on the Peace River Arch, Alberta.Lithoprobe, No. 47, pp. 346-61.Alberta, Western Canada Sedimentary basinGeophysics - seismics not specific to diamonds, Craton
DS1999-0316
1999
Hope, J.Hope, J., Eaton, D.W., Ross, G.M.Lithoprobe seismic transect of the Alberta Basin, compilation and reviewLithoprobe, No. 47, pp. 331-45.Alberta, Western Canada Sedimentary basinGeophysics - seismics not specific to diamonds, Basin
DS2002-0736
2002
Hope, J.Hope, J., Eaton, D.Crustal structure beneath the Western Canada Sedimentary Basin: constraints form gravity - magneticCanadian Journal of Earth Science, Vol.39,3,Mar.pp.291-312., Vol.39,3,Mar.pp.291-312.AlbertaGeophysics - gravity, Kimiwan High, Thorsby Low, Red Deer High, Eyehill Low
DS2002-0737
2002
Hope, J.Hope, J., Eaton, D.Crustal structure beneath the Western Canada Sedimentary Basin: constraints form gravity - magneticCanadian Journal of Earth Science, Vol.39,3,Mar.pp.291-312., Vol.39,3,Mar.pp.291-312.AlbertaGeophysics - gravity, Kimiwan High, Thorsby Low, Red Deer High, Eyehill Low
DS2003-0362
2003
Hope, J.Eaton, D.W., Hope, J.Structure of the crust and upper mantle of the Great Slave Lake shear zoneCanadian Journal of Earth Sciences, Vol. 40, 9,Sept. 1203-1218.Northwest TerritoriesGeophysics - seismics, tectonics
DS200412-0499
2003
Hope, J.Eaton, D.W., Hope, J.Structure of the crust and upper mantle of the Great Slave Lake shear zone, northwestern Canada, from teleseismic analysis and gCanadian Journal of Earth Sciences, Vol. 40, 9,Sept. 1203-1218.Canada, Northwest TerritoriesGeophysics - seismics, tectonics
DS200512-1175
2005
Hope, J.White, D.J., Thomas, M.D., Jones, A.G., Hope, J., Nemeth, B., Hajnal, Z.Geophysical transect across a Paleoproterozoic continent-continent collision zone: the Trans-Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 385-402.Canada, Northwest TerritoriesGeophysics - seismics
DS2003-0602
2003
Hopf, H.Hopf, H.Diamonds from crude oil?Angewandte Chemie, Vol. 42, 18, pp. 2002-4.GlobalMineral chemistry
DS200412-0852
2003
Hopf, H.Hopf, H.Diamonds from crude oil?Angewandte Chemie, Vol. 42, 18, pp. 2002-4.TechnologyMineral chemistry
DS1995-0820
1995
Hopggod, A.M.Hopggod, A.M., Bowes, D.R., Tonika, J.Application of structural sucession to characterization of the Bohemian Forest tectonic domain... Hercynides.Neues Jahrbuch fnr Mineralogie Abh, Vol. 169, No. 2, pp. 119-156GlobalStructure, Tectonics
DS1995-0821
1995
Hopgood, A.M.Hopgood, A.M., Bowes, D.R.Matching Gondwanaland fragments: the significance of granitoid veins and tectonic structures in southwest AustraliaJournal of Southeast Asian Earth Sciences, Vol. 11, No. 3, pp. 253-263AustraliaGondwanaland, Tectonics
DS1991-0729
1991
Hopkins, D.M.Hopkins, D.M.An analytical method for hydrogeochemical surveys: inductively coupled plasma atomic emission spectrometry after using enrichment coprecipitation with cobalt and amM.Journal of Geochemical Exploration, Vol. 41, No. 3, November pp. 349-362Colorado, Arizona, AlaskaGeochemistry, Spectrometry
DS1994-0993
1994
Hopkins, J.C.Lawton, D.C., Spratt, D.A., Hopkins, J.C.Tectonic wedging beneath the Rocky Mountain foreland basin, Alberta, Canada.Geology, Vol. 22, No. 6, June pp. 519-522.AlbertaStructure, Tectonics
DS2003-1294
2003
Hopkins, M.Sloan, J., Henry, C.D., Hopkins, M., Ludington, S.National geochronological database. Original databse by Zartman, Bush and AbstonU.s.g.s. Open File, Http://geopubs.wr.usgs.gov/open-file/of3-236, United StatesGeochronology - database ( not specific to diamonds)
DS200412-1854
2003
Hopkins, M.Sloan, J., Henry, C.D., Hopkins, M., Ludington, S.National geochronological database. Original databse by Zartman, Bush and Abston.U.S. Geological Survey, United StatesGeochronology - database ( not specific to diamonds)
DS201112-0448
2010
Hopkins, M.D.Hopkins, M.D., Harrison, T.M., Manning, C.E.Constraints on Hadean geodynamics from mineral inclusions in > 4 Ga zircons.Earth and Planetary Science Letters, Vol. 298, 3-4, pp. 367-376.MantleGeochronology
DS1993-1633
1993
Hopkins, R.Urquhart, W.E.S., Hopkins, R.Exploration geophysics and the search for Diamondiferous diatremesProspectors and Developers Diamond Workshop, held March 27th, Toronto, 36p.Canada, GlobalGeophysics, Diatremes, diamond
DS201112-0449
2011
Hopkins, R.Hopkins, R.Renard: establishing a diamond resource in Quebec.PDAC 2011, Monday March 7, 1/2p. abstractCanada, QuebecGeology and overview
DS1900-0062
1901
Hopkins, T.C.Hopkins, T.C.Diamonds in Indiana. #1Copy of Memo From Syracuse University., United States, Indiana, Great LakesDiamond Occurrence
DS1900-0256
1904
Hopkins, T.C.Hopkins, T.C.Mineral Resources of Onondaga County, New YorkNew York State Annual Report, No. 56, PP. 109-114.United States, Appalachia, New YorkGeology, Peridotite
DS1900-0328
1905
Hopkins, T.C.Hopkins, T.C.Diamonds in New York. #3Science., N.S. Vol. 22, Nov. 24TH. P. 673.United States, Appalachia, New YorkDiamond Occurrence
DS1910-0418
1914
Hopkins, T.C.Hopkins, T.C.The Geology of the Syracuse QuadrangleNew York State Mus. Bulletin., No. 171, PP. 53-56.United States, Appalachia, New YorkGeology
DS200512-0118
2005
Hopp, J.Buikin, A., Trieloff, M., Hopp,J., Althaus, T., Korochantseva, E., Schwarz, W.H., Altherr, R.Noble gas isotopes suggest deep mantle plume source of late Cenozoic mafic alkaline volcanism in Europe.Earth and Planetary Science Letters, Vol. 230, 1-2, pp. 143-162.EuropeAlkaline rocks, geochronology
DS200812-0484
2008
Hopp, J.Hopp, J., Trieloff, M., Brey, G.P., Woodland, A.B., Simon, N.S.C., Wijbrans, J.R., Siebel, W., Reitter, E.40 Ar 39 Ar ages of phlogopite in mantle xenoliths from South African kimberlites: evidence for metasomatic mantle impregnation during Kilbaran orogenic cycle.Lithos, Vol. 106, no. 3-4, pp. 351-364.Africa, South Africa, LesothoDeposit - Bultfontein, Letseng, Liqhobong
DS200812-0485
2008
Hopp, J.Hopp, J.,Trieloff, M.Noble gases in kimberlitic mantle: xenoliths from southern Africa.Goldschmidt Conference 2008, Abstract p.A390.Africa, South Africa, lesothoDeposit - Byltfontein, Finsch, Letseng
DS201112-0125
2010
Hopp, J.Buikin, A.I., Trieloff, M., Korochantseeva, E.V., Hopp, J., Kaliwood, M., Meyer, H-P.,Altherr, R.Distribution of mantle and atmospheric argon in mantle xenoliths from western Arabian Peninsula: constraints on timing and composition of metasomatizing agents....Journal of Petrology, Vol. 51, pp. 2547-2570.Africa, ArabiaMetasomatism
DS201112-0450
2011
Hopp, J.Hopp, J., Dmitri, A.Tracing partial melting and subduction related metasomatism in the Kamchatkan mantle wedge using noble gas compositions.Earth and Planetary Science Letters, Vol. 302, 1-2, pp. 121-131.RussiaMetasomatism - not specific to diamonds
DS201707-1311
2017
Hopp, J.Buikin, A.I., Kogarko, L.N., Hopp, J., Trieloff, M.Light noble gas dat a in Guli massif carbonatites reveal the subcontinental lithospheric mantle as primary fluid source.Geochemistry International, Vol. 55, 5, pp. 457-464.Russiacarbonatite - Guli

Abstract: For better understanding of the fluid phase sources of carbonatites of Guli alkaline-ultrabasic intrusion (Maymecha-Kotuy complex) we have studied isotope composition of He and Ne in the carbonatites of different formation stages. The data definitely point to the subcontinental lithospheric mantle (SCLM) as a primary source of fluid phase of Guli carbonatites. The absence of plume signature in such a plume-like object (from petrological point of view) could be explained in terms that Guli carbonatites have been formed at the waning stage of plume magmatic activity with an essential input of SCLM components.
DS201801-0023
2017
Hopp, J.Hopp, J., Viladkar, S.G.Noble gas composition of Indian carbonatites ( Amba Dongar, Siriwasan): implications on mantle source compositions and late stage hydrothermal processes.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 10.Indiadeposit - Amba Dongar, Siriwasan

Abstract: Within a stepwise crushing study we determined the noble gas composition of several calcite separates, one aegirine and one pyrochlore-aegirine separate of the carbonatite ring dyke complex of Amba Dongar and carbonatite sill complex of Siriwasan, India. Both carbonatites are related to the waning stages of volcanic activity of the Deccan Igneous Province ca. 65 Ma ago. Major observations are a clear radiogenic 4He* and nucleogenic 21Ne* imprint related to insitu production from U and Th in mineral impurities, most likely minute apatite grains. However, in first crushing steps of most calcites from Amba Dongar a well-resolvable mantle neon signal is observed, with lowest air-corrected mantle 21Ne/22Ne-compositions equivalent to the Réunion hotspot mantle source. In case of the aegirine separate from Siriwasan we found a neon composition similar to the Loihi hotspot mantle source. We conclude that previously derived models of a lithospheric mantle source containing recycled components in generation of the carbonatitic magmas from Amba Dongar are obsolete. Instead, the mantle source of both investigated carbonatite complexes is related to a primitive mantle plume source that we tentatively ascribe to the postulated Deccan mantle plume. If, as is commonly suggested, the present location of the Deccan mantle plume source is below Réunion Island, the currently observed more nucleogenic neon isotopic composition of the Réunion hotspot might be obliterated by significant upper mantle contributions, similar to Kilauea Volcano, Hawai’i. In addition, compared with other carbonatite complexes worldwide a rather significant contribution of atmospheric noble gases is observed. This is documented in cut-off 20Ne/22Ne-ratios of ca. 10.2 (Amba Dongar) and 10.45 (Siriwasan) and cut-off 40Ar/36Ar-ratios of about 1500. This atmospheric component likely had been added at shallow levels during the emplacement process. However, understanding the late-stage interaction between atmospheric gases and magmatic mantle fluids still requires further investigation.
DS201805-0951
2018
Hopp, J.Hopp, J., Viladkar, S.G.Noble gas composition of Indian carbonatites ( Amba Dongar, Siriwasan): implications on mantle source compositions and late stage hydrothermal processes.Earth Planetary Science Letters, Vol. 492, pp. 186-196.Indiacarbonatite

Abstract: Within a stepwise crushing study we determined the noble gas composition of several calcite separates, one aegirine and one pyrochlore-aegirine separate of the carbonatite ring dyke complex of Amba Dongar and carbonatite sill complex of Siriwasan, India. Both carbonatites are related to the waning stages of volcanic activity of the Deccan Igneous Province ca. 65 Ma ago. Major observations are a clear radiogenic 4He and nucleogenic 21Ne imprint related to in situ production from U and Th in mineral impurities, most likely minute apatite grains, or late incorporation of crustal fluids. However, in first crushing steps of most calcites from Amba Dongar a well-resolvable mantle neon signal is observed, with lowest air-corrected mantle 21Ne/22Ne-compositions equivalent to the Réunion hotspot mantle source. In case of the aegirine separate from Siriwasan we found a neon composition similar to the Loihi hotspot mantle source. This transition from a mantle plume signal in first crushing step to a more nucleogenic signature with progressive crushing indicates the presence of an external (crustal) or in situ nucleogenic component unrelated and superposed to the initial mantle neon component whose composition is best approximated by results of first crushing step(s). This contradicts previous models of a lithospheric mantle source of the carbonatitic magmas from Amba Dongar containing recycled crustal components which base on nucleogenic neon compositions. Instead, the mantle source of both investigated carbonatite complexes is related to a primitive mantle plume source that we tentatively ascribe to the postulated Deccan mantle plume. If, as is commonly suggested, the present location of the Deccan mantle plume source is below Réunion Island, the currently observed more nucleogenic neon isotopic composition of the Réunion hotspot might be obliterated by significant upper mantle contributions. In addition, compared with other carbonatite complexes worldwide a rather significant contribution of atmospheric noble gases is observed. This is documented in cut-off 20Ne/22Ne-ratios of ca. 10.2 (Amba Dongar) and 10.45 (Siriwasan) and cut-off 40Ar/36Ar-ratios of about 1500. This atmospheric component had been added at shallow levels during the emplacement process or later during hydrothermal alteration. However, understanding the late-stage interaction between atmospheric gases and magmatic mantle fluids still requires further investigation.
DS201809-2037
2018
Hopp, T.Hopp, T., Kleine, T.Nature of late accretion to Earth inferred from mass dependent Ru isotopic compositions of chondites and mantle peridotites.Earth and Planetary Science Letters, Vol. 494, 1, pp. 50-59.Mantleperidotites

Abstract: Elevated abundances of highly siderophile elements in Earth's mantle are thought to reflect the late accretion of primitive material after the cessation of core formation, but the origin of this material, and whether or not it can be linked to specific types of meteorites remain debated. Here, mass-dependent Ru isotopic data for chondrites and terrestrial peridotites are reported to evaluate the chemical nature and type of the late-accreted material. After correction for nucleosynthetic Ru isotope anomalies, enstatite, ordinary and carbonaceous chondrites all have indistinguishable mass-dependent Ru isotopic compositions. Thus, neither distinct formation conditions in the solar nebula nor parent body processes resulted in significant mass-dependent Ru isotope fractionation. All five terrestrial peridotites analyzed have mass-dependent Ru isotopic compositions that are indistinguishable from each other and from the composition of chondrites. The chondritic mass-dependent Ru isotopic composition of Earth's mantle is difficult to reconcile with prior suggestions that the late accretionary assemblage was a mixture of chondrites with a chemically evolved metal component. Although this mixture can reproduce the suprachondritic Ru/Ir inferred for Earth's mantle, it consistently predicts a heavy Ru isotopic composition of Earth's mantle with respect to chondrites. This is because metal components with elevated Ru/Ir are also enriched in heavy Ru isotopes, resulting from isotope fractionation during core crystallization. Thus, if late accretion involved impacts of differentiated protoplanetary bodies, then the projectile cores must have been either homogenized upon impact, or added to Earth's mantle completely, because otherwise Earth's mantle would have inherited a non-chondritic mass-dependent Ru isotopic composition from the unrepresentative sampling of core material.
DS1992-0726
1992
HoppeHoppeThe Amazon between economy and ecologyNatural Resources forum, Vol. 16, No. 3, August pp. 232-234BrazilEconomics, Amazon -environment
DS1996-0713
1996
Hoppe, A.Karfunkel, J., Chaves, M.I.S.C., Banko, A., Hoppe, A.Diamond in time and space: an example from central -eastern BrasilInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 504.BrazilTectonics, Weathering
DS2001-0177
2001
Hoppe, A.Chaves, M.L., Karfunkel, J., Hoppe, A., Hoover, D.B.Diamonds from the Espinaco Range and their redistribution through the geologic record.Journal of South American Earth Sciences, Vol. 14, No. 3, pp. 277-89.Brazil, Minas GeraisDiamond - morphology, Alluvials, genesis
DS1980-0177
1980
Hoppe, R.Hoppe, R.Diamonds from the KalahariEngineering and Mining Journal, Vol. 181 No. 5, PP. 64-69.South Africa, BotswanaDiamond Mining Recovery, Kimberlite Pipes
DS1981-0083
1981
Hoppe, W.J.Bickford, M.E., Harrower, K.L., Hoppe, W.J., Nelson, B.K., Nusba.Rubidium-strontium (rb-sr) and U-pb and Geochronology and Distribution of Rock TyGeological Society of America (GSA) Bulletin., Vol. 92, PT. 1, PP. 323-341.GlobalMid-continent
DS201412-0369
2014
Hopper, E.Hopper, E., Ford, H.A., Fischer, K.M., Lekic, V., Fouch, M.J.The lithosphere-asthenosphere boundary and the tectonic and magmatic history of the northwestern United States.Earth and Planetary Science Letters, Vol. 402, pp. 69-81.United StatesGeophysics - seismics
DS201603-0386
2015
Hopper, E.Hopper, E., Fischer, K.M.The meaning of midlithospheric discontinuities: a case study in the northern U.S. craton.Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 12, pp. 4057-4083.United StatesGeophysics - seismics
DS201702-0215
2016
Hopper, E.Hopper, E., Fischer, K.M., Rondenay, S., Hawman, R.B., Wagner, L.S.Imaging crustal structure beneath the southern Appalachians with wavefield migration.Geophysical Research Letters, Vol. 43, 23, pp. 12,054-62.United StatesGeophysics - seismics

Abstract: To constrain crustal structures in the southern Appalachians and the suture zone with the Gondwanan-affinity Suwannee terrane, we applied the 2-D generalized Radon transform wavefield migration method to the scattered incident P wavefield recorded by the EarthScope Southeastern Suture of the Appalachian Margin Experiment and adjacent Transportable Array stations. We resolve the root of thickened crust beneath the high topography of the Blue Ridge Mountains and estimate its density contrast with the mantle to be only 104?±?20?kg/m3. A weak velocity contrast across the crustal root Moho is observed and may be related to an ongoing crustal delamination event, possibly contributing to local tectonic rejuvenation. Beneath the Suwannee terrane, we confirm prior observations of a gently south-southeastward dipping crustal suture, indicating the terminal collision of Laurentia and Gondwana involved several hundred kilometers of overthrusting.
DS201810-2328
2018
Hopper, E.Hopper, E., Fischer, K.M.The changing face of the lithosphere, asthenosphere boundary: imaging continental scale patterns in upper mantle structure across the contiguous U.S. with Sp converted waves.Geochemistry, Geophysics, Geosystems, Vol. 19, 8, pp. 2593-2614.United Statesgeophysics - seismic

Abstract: Juxtaposed terranes of highly varied tectonic history make up the contiguous U.S.: the tectonically active western U.S., the largely quiescent Archean and Proterozoic cratons of the central U.S., and the Phanerozoic orogen and rifted margin of the eastern U.S. The transitions between these regions are clearly observed with Sp converted wave images of the uppermost mantle. We use common conversion point stacked Sp waves recorded by EarthScope's Transportable Array and other permanent and temporary broadband stations to image the transition from a strong velocity decrease at the lithosphere-asthenosphere boundary (or LAB) beneath the western U.S. to deeper, less continuous features moving east that largely lie within the lithosphere. Only sparse, localized, weak phases are seen at LAB depths beneath the cratonic interior. Instead, we observe structures within the cratonic lithosphere that are most prominent within the Archean lithosphere of the Superior Craton. The transition from west to east is clearly revealed by cluster analysis, which also shows eastern U.S. mantle velocity gradients as more similar to the western U.S. than the ancient interior, particularly beneath New England and Virginia. In the western U.S., the observed strong LAB indicates a large enough velocity gradient (an average velocity drop of 10?±?4.5% distributed over 30?±?15 km) to imply that melt has ponded beneath the lithosphere.
DS2001-0285
2001
Hopper, J.M.G.Dyke, A.S., Hopper, J.M.G.Deglaciation of northwest Baffin Island, Nunavut. NTS 47 C,D,E,F,G,H, 48A,B,C,D, 57 E.H.,58 A,D.Geological Survey of Canada (GSC) Map, No. 19991, 1:500,000Northwest Territories, Nunavut, Baffin IslandGeomorphology
DS1993-0698
1993
Hopper, J.R.Hopper, J.R., Buck, W.R.Decoupling of the crust and mantle: the effect of a weak lower crust onlithospheric deformationGeological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A197 abstract onlyChinaLithosphere, M