Kaiser Bottom Fish OnlineFree trialNew StuffHow It WorksContact UsTerms of UseHome
Specializing in Canadian Stocks
SearchAdvanced Search
Welcome Guest User   (more...)
Home / Education
Education
 

SDLRC - Scientific Articles all years by Author - Mar-Mh


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 - Mar-Mc
Posted/
Published
AuthorTitleSourceRegionKeywords
DS201012-0574
2010
Maraeschal, J-C.Perry, C., Rosieanu, C., Maraeschal, J-C., Jaupart, C.Thermal regime of the lithosphere in the Canadian shield.Canadian Journal of Earth Sciences, Vol. 47, 4, pp. 389-408.Canada, Northwest TerritoriesGeothermometry
DS201312-0573
2013
Maragoni, Y.R.Maragoni, Y.R., Mantovani, M.S.M.Geophysical signatures of the alkaline intrusions bordering on the Parana Bain.Journal of South American Earth Sciences, Vol. 41, pp. 83-98.South America, BrazilGeophysics - alkaline
DS1994-1100
1994
Marahushev, A.A.Marahushev, A.A., et al.Polyfacial characteristics of the Diamondiferous rocks in kimberlite and lamproite pipes.(Russian)Doklady Academy of Sciences Nauk., (Russian), Vol. 337, No. 4, August pp. 490-493.RussiaPetrology, Kimberlite, lamproite
DS1960-0862
1967
Marais, D.Marais, D.The Diamond Industry in South Africa Will Virtually Come Toa Standstill in 20 Years Unless New Sources of Diamonds Are found Soon.Mining And Minerals, FEBRUARY.South AfricaProspecting
DS1985-0411
1985
Marais, J.Marais, J.Namaqualand; Where It All Began 300 Years AgoSth. Afr. Mining, Coal, Gold and Base Metals, October pp. 33-39South AfricaHistory
DS1990-1294
1990
Marais, M.G.Salter, J.D., Downing, B.J., Rix, G.M., Marais, M.G.Development of rock pass level monitors for Finsch diamond mine, SouthAfrica14th. Cmmi Congress Held Edinburgh, Scotland July 2-6, 1990 Institute Of Mining And Metallurgy (imm) Proceedings, pp. 107-111South AfricaMining, Finsch mine
DS1995-1159
1995
Marajushev, A.A.Marajushev, A.A.Geological position, geochemistry and thermodynamics of diamondiferousimpactogenesis.Moscow University Geology Bulletin, Vol. 30, No. 1, pp. 1-19.RussiaGeochemistry, Meteorites, craters
DS1996-0882
1996
Marajushev, A.A.Marajushev, A.A., et al.The origin of diamonds in meteoritesDoklady Academy of Sciences, Vol. 344 No. 7, August pp. 165-171.GlobalMeteorites, Diamond genesis
DS1981-0281
1981
Marakushev, A.A.Marakushev, A.A.The Problem of Fluid Regime in the Formation of Diamondifero united States Rocks.Geol. Rudn. Mestorezhd., Vol. 23, No. 4, PP. 3-17.RussiaDiamond, Genesis
DS1982-0392
1982
Marakushev, A.A.Marakushev, A.A.The Diamond Bearing Igneous Rocks of Kimberlite PipesDoklady Academy of Sciences ACAD. NAUK USSR, EARTH SCI. SECTION., Vol. 256, No. 1-6, PP. 91-94.RussiaGenesis
DS1982-0393
1982
Marakushev, A.A.Marakushev, A.A.The Volcanic Nature of the Diamond Bearing Rocks of Kimberlite Pipes.Soviet Geology and GEOPHYSICS, Vol. 23, No. 8, PP. 13-23.RussiaKimberlite Genesis
DS1982-0394
1982
Marakushev, A.A.Marakushev, A.A.Problems of Genesis of Rocks With Plagioclase and DiamondsMineral. Zhurnal, Vol. 4, No. 4, PP. 14-22.RussiaBlank
DS1982-0395
1982
Marakushev, A.A.Marakushev, A.A.The Fluid Regime in the Formation of Diamond Containing RockInternational Geology Review, Vol. 24, No. 11, PP. 1241-1252.Russia, YakutiaMir, Mineral Inclusions, Mineralogy, Petrography, Diamond, Pyroxene
DS1983-0432
1983
Marakushev, A.A.Marakushev, A.A., Garanin, V.K., Kudryavtseva, G.P.The Mineralogy and Petrology of Kimberlite Pipes and Diamond Bearing Rocks.Annales Scientifiques De L' Universite De Clermont-ferrand Ii, No. 74, PP. 47-54.RussiaPetrography, Genesis, Magma
DS1984-0477
1984
Marakushev, A.A.Marakushev, A.A.Peridotite nodules in kimberlites and basalts as indicators for lithosphere deep seated structureIn: Proceedings of the 27th. International Geological Congress held Moscow, August, Vol. 9, Petrology pp. 327-342RussiaTectonics, Mantle
DS1984-0478
1984
Marakushev, A.A.Marakushev, A.A.The Petrography of Plutonic Inclusions in Kimberlites and BasaltsIzvest. Vyssh. Uchebn. Zaved. Geol. I. Razv., No. 1, PP. 37-54.RussiaBlank
DS1984-0479
1984
Marakushev, A.A.Marakushev, A.A.The Petrography of Deep Seated Nodules in Kimberltes and Basalts.International Geology Review, Vol. 26, No. 6, JUNE PP. 635-650.RussiaBlank
DS1984-0480
1984
Marakushev, A.A.Marakushev, A.A., Bezmen, N.I., Skufin, P.K., Smolkin, V.F.Layered Nickel Bearing Intrusions and Volcanic Series of Pechenga.(russian)Ocherki Fiz. Khim. Petrol., (Russian), Vol. 1, pp. 39-63RussiaBlank
DS1985-0412
1985
Marakushev, A.A.Marakushev, A.A.Mineral associations of diamond and the formation of diamondbearingmagmas.(Russian)Ocherki. Fiz. Khim. Petrol., (Russian), Vol. 13, pp. 5-53RussiaBlank
DS1986-0523
1986
Marakushev, A.A.Marakushev, A.A.Mineral associations of diamond and the problem of the formation of diamond containing magmas. (Russian)Ocherki Fiz. Khim. Petrol. Moskva, (Russian), Vol. 13, pp. 50-53RussiaDiamond morphology
DS1987-0235
1987
Marakushev, A.A.Garanin, V.K., Kudrryavtseva, G.P., Marakushev, A.A., CherenkovaA new variety of deep seated high alumin a rock in kimberlite pipesInternational Geology Review, Vol. 29, No. 11, November pp. 1366-1376RussiaFerroalkremite, analyses, Anabar region
DS1991-1048
1991
Marakushev, A.A.Marakushev, A.A., Yemelyanenko, Ye.P., et al.Formation of the concentrically zoned structure of the Konderalkalic-ultrabasic plutonDoklady Academy of Science USSR, Earth Science Section, Vol. 311, Nove. 1-6, pp. 69-72RussiaAlkaline rocks, Konder
DS1993-0970
1993
Marakushev, A.A.Marakushev, A.A.Geodynamic regions of diamond formation.(Russian)Bulletin. Mosk. Obschestva Ispyt. Prirody Otdel Geol.(Russian), Vol. 68, 2, pp. 3-18.Russia, YakutiaTectonics
DS1995-1160
1995
Marakushev, A.A.Marakushev, A.A., Mitreiki, O.B., et al.Origin of diamonds in meteorites. (Russian)Doklady Academy of Sciences Nauk. (Russian), Vol. 341, No. 3, March pp. 106-109.RussiaMeteorites
DS1995-1161
1995
Marakushev, A.A.Marakushev, A.A., Mitreikina, O.B., Zinolieva, GranovskyDiamondiferous meteorites and their genesisPetrology, Vol. 3, No. 5, Sept-Oct. pp. 407-423.RussiaMeteorites
DS1995-1162
1995
Marakushev, A.A.Marakushev, A.A., Pertsev, N.N., Zotov, I.A., Paneyakh, N.Some petrological aspects of diamond genesisGeology of Ore Deposits, Vol. 37, No. 2, March-April pp. 88-102.RussiaDiamond genesis, lamproite, Petrology
DS1995-1163
1995
Marakushev, A.A.Marakushev, A.A., Pertsev, N.N., Zotov, I.A., Paneyakh, N.A.Petrology of Diamondiferous magmatismProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 350-351.MantleMagmatism, Metamorphic complexes
DS1996-0883
1996
Marakushev, A.A.Marakushev, A.A., et al.Polyfacies nature of diamond bearing rocks from kimberlite and lamproitepipes.Doklady Academy of Sciences, Vol. 339A, No. 9, Feb., pp. 64-69.RussiaPeridotites, eclogites, Magma
DS1996-0884
1996
Marakushev, A.A.Marakushev, A.A., Pertsev, N.N., Zotov, I.A., PaneyakhSome petrological aspects of genesis of diamondInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 2, p. 400.RussiaPetrology, Diamond genesis
DS1997-0729
1997
Marakushev, A.A.Marakushev, A.A.Ore bearing potential of impact ring structureGeology of Ore Deposits, Vol. 38, No. 6, pp. 442-453.RussiaImpact structure, Puchezh-Katun, Popigai, Diamond
DS1998-0937
1998
Marakushev, A.A.Marakushev, A.A., Bobrov, A.V.Specific features of crystallization of eclogite magmas at the diamond facies depths.Doklady Academy of Sciences, ol. 358, No. 1, pp. 142-5.RussiaEclogite, Crystallography
DS1998-0938
1998
Marakushev, A.A.Marakushev, A.A., Bobrov, A.V.Crystallization of eclogite and pyroxenite magmas in diamond depth facies:evidence from garnet-clinopyrox.7th International Kimberlite Conference Abstract, pp. 546-8.Russia, YakutiaDiamond inclusions, Deposit - Udachnaya
DS1998-0939
1998
Marakushev, A.A.Marakushev, A.A., Paneyakh, N.A., Rusinov, PertsovPetrological model of giant ore depositsGeology of Ore Deposits, Vol. 40, No. 3, May-June pp. 211-227RussiaMetallogeny, Petrology
DS1998-0940
1998
Marakushev, A.A.Marakushev, A.A., Suk, N.I.Carbonate silicate magmatic immiscibility and carbonatite genesisDoklady Academy of Sciences, Vol. 361, No. 5, pp. 696-99.GlobalCarbonatite - genesis
DS2001-0731
2001
Marakushev, A.A.Marakushev, A.A., Shakhotko, L.I.Formation stages and nature of the Popigai Diamondiferous ring structureDoklady Academy of Sciences, Vol. 3771, March/April pp. 274-77.RussiaTectonics - structure, Deposit - Popigai
DS200512-0685
2003
Marakushev, A.A.Marakushev, A.A., Lonkan, S., Bobrov, A.V., Hengweng, Z., Fu, L.Evolution of the SuLu eclogite ultramafic foldbelt in East China.Moscow University Geology Bulletin, Vol. 58, 6, pp. 33-46.ChinaUHP
DS200612-0864
2005
Marakushev, A.A.Marakushev, A.A., Bobrov, A.V.Problems of primary magma and the depths of Diamondiferous magmatism.Doklady Earth Sciences, Vol. 403A, 6, pp. 901-904.MantleMagmatism
DS201606-1086
2016
Maram, P.S.Feng, D., Maram, P.S., Mielewczyk-Gryn, A., Navotsky, A.Thermochemistry of rare earth perovskites Na3xRE.067-xTiO3 ( Re=La, Ce)American Mineralogist, Vol. 101, 5, pp. 1125-1128.TechnologyPerovskite
DS201112-0269
2010
Maran, N.Dinesh, A.C., Maran, N., Shareef, N.M., Chandrasekaraiah, K.C., Jayaprakash, C.Observations on the reported incidence of micro-diamonds in the beach sands of the Kanyakumari Coast, Tamil Nadu.Journal of the Geological Society of India, Vol. 76, 6, pp. 587-588.IndiaAlluvials
DS201112-0270
2010
Maran, N.Dinesh, A.C., Maran, N., Shareef, N.M., Chandrasekaraih, K.C., Jayaprakash, C.Observations on the reported incidence of micro-diamonds in the beach sands of the Kanyakumari coast, Tamil Nadu.Journal of the Geological Society of India, Vol. 76, pp. 587-588.India, Tamil NaduMicrodiamonds
DS201212-0442
2012
Marangoni, Y.R.Marangoni, Y.R., Mantovani, M.S.M.Geophysical signatures of the alkaline intrusions bordering the Parana Basin.Journal of South American Earth Sciences, in press available, 48p.South America, Paraguay, BrazilGeophysics - magnetics
DS200412-2012
2003
Marani, M.P.Trua, T., Serri, G., Marani, M.P.Lateral flow of African mantle below the nearby Tyrrhenian plate: geochemical evidence.Terra Nova, Vol. 15, 6, pp. 433-440.AfricaGeochemistry
DS200412-1223
2004
Maraschal, J.C.Maraschal, J.C., Nyblade, A., Perry, H.K.C., Jaupart, C., Bienfait, G.Heat flow and deep lithospheric thermal structure at Lac de Gras Slave Province, Canada.Geophysical Research Letters, Vol. 31, 12, June 28, 10.1029/2004 GLO20133Canada, Northwest TerritoriesGeothermometry
DS200412-0071
2004
Maraschal, J-C.Audet, P., Maraschal, J-C.Variations in elastic thickness in the Canadian Shield.Earth and Planetary Science Letters, Vol. 226, 1-2, Sept. 30, pp.17-31.Canada, Saskatchewan, Manitoba, OntarioGravity, isostasy. Hudson Bay, Williston Basin
DS1992-0993
1992
Maraschal, M.Maraschal, M., Fyfe, W.S., Percival, J., Chan, T.Grain-boundary graphite in Kapuskasing gneisses and implications for lower-crustal conductivityNature, Vol. 357, No. 6380, June 25, pp. 674-676OntarioGeophysics, Kapuskasing uplift
DS1986-0524
1986
Maraukshev, A.A.Maraukshev, A.A., Taskaev, V.I.Composition variations in minerals from garnetiferous peridotites and eclogites and their genetic significance.(Russian)Izv. Vyssh. Uchebn. Zaved. Geol. Razved., (Russian), No. 5, pp. 9-41RussiaEclogite
DS1989-0931
1989
Maravic, H.v.Maravic, H.v., Mortenai, G., Roethe, G.The cancrinite-syenite/carbonatite complex of Lueshe,Kivu/northeast Zaire:petrographic and geochemical studies and its economic significanceJournal of African Earth Sciences, Vol. 9, No. 2, pp. 341-355Democratic Republic of CongoCarbonatite, Geochemistry, petrography
DS1997-0631
1997
Maravic, H.V.Kramm, U., Maravic, H.V., Morteani, G.Neodynium and Strontium isotopic constraints on the petrogenetic relationships between carbonatites...Journal of African Earth Sciences, Vol. 25, No. 1, July pp. 55-76.Democratic Republic of CongoCarbonatite, Cancrinite syenites, Lueshe alkaline complex
DS201012-0460
2010
Marazzo, M.Lustrino, M., Marazzo, M., Melluso, L., Tassinari, C.C.G., Brotzu, P., Gomes, C.B., Morbidelli, RubertiPetrogenesis of early Cretaceous silicic volcanism in se Uruguay: the role of mantle and crustal sources.Geochemical Journal, Vol. 44, 1, pp. 1-22.South America, UruguayRhyolites - not specific diamonds - backgrounder
DS1989-0932
1989
Marbeau, J-P.Marbeau, J-P.The importance of modeling. the microcomputer can now model deposits sowell that it has become a basic tool of explorationEngineering and Mining Journal, Vol. 190, No. 11, November pp. 22-25GlobalComputer, Deposit modeling -overview
DS1999-0443
1999
Marcano, M.C.Marcano, M.C., Van Der Voo, R., MacNiocaill C.True polar wander during the Permo-TriassicJournal of Geodynamics, Vol. 28, No. 2-3, Sept. 2, pp. 75-95.MantleGeophysics - thermodynamics, Lithosphere
DS1990-0365
1990
Marcantonio, F.Corriveau, L., Heaman, L.M., Marcantonio, F., Vanbreemen, O.1.1 GA potassium-rich alkaline plutonism in the southwest Grenville province-Contributions to Mineralogy and Petrology, Vol. 105, No. 4, pp. 473-485OntarioAlkaline rocks, Geochronology
DS202012-2206
2020
Marcelli, M.Borisova, A.Y., Bindeman, I.N., Toplis, M.J., Zagrtdenov, N.R., Guignard, J., Safonov, O.G., Bychkov, A.Y., Shcheka, S., Melnik, O.E., Marcelli, M., Fehrenbach, J.Zircon survival in shallow asthenosphere and deep lithosphere.American Mineralogist, Vol. 105, pp. 1662-1671. pdfMantlemelting

Abstract: Zircon is the most frequently used mineral for dating terrestrial and extraterrestrial rocks. However, the system of zircon in mafic/ultramafic melts has been rarely explored experimentally and most existing models based on the felsic, intermediate and/or synthetic systems are probably not applicable for prediction of zircon survival in terrestrial shallow asthenosphere. In order to determine the zircon stability in such natural systems, we have performed high-temperature experiments of zircon dissolution in natural mid-ocean ridge basaltic and synthetic haplobasaltic melts coupled with in situ electron probe microanalyses of the experimental products at high current. Taking into account the secondary fluorescence effect in zircon glass pairs during electron microprobe analysis, we have calculated zirconium diffusion coefficient necessary to predict zircon survival in asthenospheric melts of tholeiitic basalt composition. The data imply that typical 100 micron zircons dissolve rapidly (in 10 hours) and congruently upon the reaction with basaltic melt at mantle pressures. We observed incongruent (to crystal ZrO2 and SiO2 in melt) dissolution of zircon in natural mid-ocean ridge basaltic melt at low pressures and in haplobasaltic melt at elevated pressure. Our experimental data raise questions about the origin of zircons in mafic and ultramafic rocks, in particular, in shallow oceanic asthenosphere and deep lithosphere, as well as the meaning of the zircon-based ages estimated from the composition of these minerals. Large size zircon megacrysts in kimberlites, peridotites, alkali basalts and other magmas suggest the fast transport and short interaction between zircon and melt.The origin of zircon megacrysts is likely related to metasomatic addition of Zr into mantle as any mantle melting episode should obliterate them.
DS201711-2510
2017
MarceloAssumpcao, P.M.Farrapo Albuquerque, D., SandFranca Lucas, G., MarceloAssumpcao, P.M., Lucas, M.B., CondoriQuispe, C., Oliveira, M.E.Crustal structure of the Amazonian craton and adjacent provinces in Brazil.Journal of South American Earth Sciences, Vol. 79, pp. 431-442.South America, Brazilcraton

Abstract: The study of the crust using receiver functions can provide valuable geological information, such as average crustal composition, its formation dynamics and the tectonic evolution of a region, as well as serve as an initial reference for the generation of seismic wave velocity models to improve earthquake location. To fill in gaps in information on the crust of the Amazonian Craton and adjacent provinces in Brazil, we used receiver functions and H-k stacking to estimate crustal thicknesses and the VP/VS ratios. The results indicate that the crust of the study region is predominantly felsic, with an average VP/VS around 1.73 and an average thickness of 38.2 km, with a range of 27.4-48.6 km. Minimum curvature interpolation of the crustal thickness values has made it possible to delimitate of the Amazonian Craton, which corresponds to the area with an average thickness equal to or greater than 39 km. In addition, it was possible to identify its potential cratonic blocks, as well as the Paranapanema Block of Paraná Basin. The geometry of the craton, defined by its crustal thickness, is corroborated by the distribution of natural seismicity that accompanies its edges. These are related to suture zones between the Amazonian, São Francisco/Congo and Paranapanema paleocontinents. The sedimentary basins that have undergone rifting processes have a thinner crust, usually less than 37 km thick. Due to the great variability of the results, it was not possible to determine a characteristic value of c
DS1989-0933
1989
Marcelot, G.Marcelot, G., Dupuy, C., Dostal, J., Rancan, J.P., Pouclet, A.Geochemistry of mafic volcanic rocks from the Lake Kivu (Zaire and Rwanda)section of the western branch Of the African riftJournal of Volcanology and Geothermal Research, Vol. 39, No. 1, October pp. 73-88Democratic Republic of CongoTectonics, Rifting
DS202003-0354
2020
March, S.O'Neill, C., March, S., Bottke, W., Fu, R.The role of impacts in Archean tectonics.Geology, Vol. 48, pp. 174-178.Australia, Africa, South Africacraton

Abstract: Field evidence from the Pilbara craton (Australia) and Kaapvaal craton (South Africa) indicate that modern tectonic processes may have been operating at ca. 3.2 Ga, a time also associated with a high density of preserved Archaean impact indicators. Recent work has suggested a causative association between large impacts and tectonic processes for the Hadean. However, impact flux estimates and spherule bed characteristics suggest impactor diameters of <100 km at ca. 3.5 Ga, and it is unclear whether such impacts could perturb the global tectonic system. In this work, we develop numerical simulations of global tectonism with impacting effects, and simulate the evolution of these models throughout the Archaean for given impact fluxes. We demonstrate that moderate-size (~70 km diameter) impactors are capable of initiating short-lived subduction, and that the system response is sensitive to impactor size, proximity to other impacts, and also lithospheric thickness gradients. Large lithospheric thickness gradients may have first appeared at ca. 3.5-3.2 Ga as cratonic roots, and we postulate an association between Earth’s thermal maturation, cratonic root stability, and the onset of widespread sporadic tectonism driven by the impact flux at this time.
DS200412-0331
2004
Marchand, J.Ciesielski, A., Marchand, J., Vaillancourt, C.Volcanic hosted diamonds from northern Ontario: a non-kimberlitic origin.Geological Association of Canada Abstract Volume, May 12-14, SS14P02, p. 274.abstractCanada, OntarioVolcaniclastic breccias
DS1960-1110
1969
Marchand, M.Gold, D.P., Marchand, M.The Diatreme Breccia Pipes and Dykes and the Related Alnoite,kimberlite and Carbonatite Intrusions Occur in the Montreal Area and Oka Areas, Quebec.Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) GUIDEBOOK, GEOLOGY of THE MONTREGIAN HILLS, PP. 5-42.Canada, QuebecRelated Rocks
DS1970-0130
1970
Marchand, M.Marchand, M.Ultramafic Nodules from Ile Bizard, QuebecMsc. Thesis, Mcgill University, 73P.Canada, QuebecAlnoite, Kimberlite
DS1993-0971
1993
Marchand, M.Marchand, M.Diamond exploration in the Peace River Arch, AlbertaThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin) , Annual Meeting Abstracts approximately 10 lines, Vol. 86, No. 968, March POSTER ABSTRACT p. 68.AlbertaCraton, Tectonics
DS1995-1164
1995
Marchand, M.Marchand, M.Metallic and industrial mineral assessment report on the Horseshoe Peace River area, Alberta.Alberta Geological Survey, MIN 1995006AlbertaExploration - assessment, Ridgeway Petroleum, Horseshoe Gold Mining
DS1995-1165
1995
Marchand, M.Marchand, M.Diamond exploration in the Peace River area, AlbertaCalgary Mineral Eploration Group, Meeting April 6, 7 Abstract p. 4.AlbertaPeace River area, Geophysics
DS1997-0730
1997
Marchand, M.Marchand, M.Metallic and industrial mineral assessment report on the exploration program Horseshoe project Peace RiverAlberta Geological Survey, MIN 19970005AlbertaExploration - assessment, Ridgeway Petroleum, Horseshoe Gold
DS2003-0468
2003
Marchand, P.Girard, R., Moorhead, J., Marchand, P.Kimberlites in Quebec: current statusQuebec Exploration Conference, Nov. 25-27, 1p. abstractQuebecBrief overview
DS200412-0668
2003
Marchand, P.Girard, R., Moorhead, J., Marchand, P.Kimberlites in Quebec: current status.Quebec Exploration Conference, Nov. 25-27, 1p. abstractCanada, QuebecBrief overview
DS201412-0184
2014
Marchant, D.Devriese, S.G.R., Corcoran, N., Cowan, D., Davis, K., Bild-Enkin, D., Fournier, D., Heagy, L., Kang, S., Marchant, D., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W.Magnetic inversion of three airborne dat a sets over the Tli Kwi Cho kimberlite complex.SEG Annual Meeting Denver, pp. 1790-1794 extended abstractCanada, Northwest TerritoriesGeophysics - Tli Kwi Cho
DS201412-0250
2014
Marchant, D.Fournier, D., Heagy, L., Corcoran, N., Devriese, S.G.R., Bild-Enkin, D., Davis, K., Kang, S., Marchant, D., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W.Multi-EM systems inversion - towards a common conductivity model for Tli Kwi Cho complex.SEG Annual Meeting Denver, pp. 1795-1798. Extended abstractCanada, Northwest TerritoriesGeophysics - Tli Kwi Cho complex
DS201501-0006
2014
Marchant, D.Devriese, S.G.R., Corcoran, N., Cowan, D., Davis, K., Bild-Enkin, D., Fournier, D., Heagy, L., Kang, S., Marchant, D., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W.Magnetic inversion of three airborne dat a sets over the Tli Kwi Cho kimberlite complex.SEG Annual Meeting Denver, 5p. Extended abstractCanada, Northwest TerritoriesDeposit - Tli Kwi Cho, geophysics

Abstract: The magnetic and electromagnetic responses from airborne systems at Tli Kwi Cho, a kimberlite complex in the Northwest Territories, Canada, have received considerable attention over the last two decades but a complete understanding of the causative physical properties is not yet at hand. Our analysis is distributed among three papers. In the first, we find a 3D magnetic susceptibility model for the area; in the second, we find a 3D conductivity model; and in the third paper, we find a 3D chargeability model. Our goal is to explain all the geophysical results within a geologic framework. In this first paper, we invert three independent airborne magnetic data sets flown over the Tli Kwi Cho kimberlite complex located in the Lac de Gras kimberlite field in Northwest Territories, Canada. The complex consists of two kimberlites known as DO-27 and DO-18. An initial airborne DIGHEM survey was flown in 1992 and AeroTEM and VTEM data subsequently acquired in 2003 and 2004, respectively. In this paper, we invert each magnetic data set in three dimensions. Both kimberlites are recovered in each model, with DO-27 as a more susceptible body than DO-18. Our goal is to simultaneously invert the three data sets to generate a single susceptibility model for Tli Kwi Cho. This project is part of a larger, on-going investigation by UBC-GIF on inverting magnetic, electromagnetic, and induced polarization data from the Tli Kwi Cho area.
DS201501-0009
2014
Marchant, D.Fournier, D., Heagy, L., Corcoran, N., Cowan, D., Devriese, S.G.R., Bild-Enkin, D., Davis, K., Kang, S., Marchant, D., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W.Multi-EM systems inversion - towards a common conductivity model for Tli Kwi Cho complex.SEG Annual Meeting Denver, 5p. Extended abstractCanada, Northwest TerritoriesDeposit - Tli Kwi Cho, geophysics

Abstract: The magnetic and electromagnetic responses from airborne systems at Tli Kwi Cho, a kimberlite complex in the Northwest Territories, Canada, have received considerable attention over the last two decades but a complete understanding of the causative physical properties is not yet at hand. Our analysis is distributed among three posters. In the first we find a 3D magnetic susceptibility model for the area; in the second we find a 3D conductivity model; and in the third we find a 3D chargeability model that can explain the negative transient responses measured over the kimberlite pipes. In this second paper we focus upon the task of finding a conductivity model that is compatible with three airborne data sets flown between 1992 and 2004: one frequency-domain data set (DIGHEM) and two time-domain systems (AeroTEM and VTEM). The goal is to obtain a 3D model from which geologic questions can be answered, but even more importantly, to provide a background conductivity needed to complete the 3D IP inversion of airborne EM data. We begin by modifying our pre-existing 1D frequency and time domain inversion codes to produce models that have more lateral continuity. The results are useful in their own right but we have also found that 1D analysis is often very effective in bringing to light erroneous data, assisting in estimating noise floors, and providing some starting information for developing a background model for the 3D EM inversion. Here we show some results from our Laterally Constrained Inversion (LCI) framework. The recovered conductivity models seem to agree on the general location of the kimberlite pipes but disagree on the geometry and conductivity values at depth. The complete 3D inversions in time and frequency, needed to resolved these issues, are currently in progress.
DS201611-2103
2014
Marchant, D.Devriese, S.G.R., Corcoran, N., Cowan, D., Davis, K., Bild-Enkin, D., Fournier, D., Heagy, L., Kang, S., Marchant, D., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W.Magnetic inversion of three airborne dat a sets over the Tli Kwi Cho kimberlite complex.SEG Annual Meeting Denver, pp. 1790-1794. pdfCanada, Northwest TerritoriesDeposit - Tli Kwi Cho

Abstract: The magnetic and electromagnetic responses from airborne systems at Tli Kwi Cho, a kimberlite complex in the Northwest Territories, Canada, have received considerable attention over the last two decades but a complete understanding of the causative physical properties is not yet at hand. Our analysis is distributed among three papers. In the first, we find a 3D magnetic susceptibility model for the area; in the second, we find a 3D conductivity model; and in the third paper, we find a 3D chargeability model. Our goal is to explain all the geophysical results within a geologic framework. In this first paper, we invert three independent airborne magnetic data sets flown over the Tli Kwi Cho kimberlite complex located in the Lac de Gras kimberlite field in Northwest Territories, Canada. The complex consists of two kimberlites known as DO-27 and DO- 18. An initial airborne DIGHEM survey was flown in 1992 and AeroTEM and VTEM data subsequently acquired in 2003 and 2004, respectively. In this paper, we invert each magnetic data set in three dimensions. Both kimberlites are recovered in each model, with DO-27 as a more susceptible body than DO-18. Our goal is to simultaneously invert the three data sets to generate a single susceptibility model for Tli Kwi Cho. This project is part of a larger, on-going investigation by UBC-GIF on inverting magnetic, electromagnetic, and induced polarization data from the Tli Kwi Cho area.
DS201611-2107
2014
Marchant, M.Fournier, D., Heagy, L., Corcoran, N., Cowan, D., Devriese, S.G.R., Bild-Enkin, D., Davis, K., Marchant, M., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W.Multi-EM systems inversion - towards a common conductivity model for Tli Kwi Cho complex.SEG Annual Meeting Denver, pp. 1795-1799. pdfCanada, Northwest TerritoriesDeposit - Tli Kwi Cho

Abstract: The magnetic and electromagnetic responses from airborne systems at Tli Kwi Cho, a kimberlite complex in the Northwest Territories, Canada, have received considerable attention over the last two decades but a complete understanding of the causative physical properties is not yet at hand. Our analysis is distributed among three posters. In the first we find a 3D magnetic susceptibility model for the area; in the second we find a 3D conductivity model; and in the third we find a 3D chargeability model that can explain the negative transient responses measured over the kimberlite pipes. In this second paper we focus upon the task of finding a conductivity model that is compatible with three airborne data sets flown between 1992 and 2004: one frequency-domain data set (DIGHEM) and two time-domain systems (AeroTEM and VTEM). The goal is to obtain a 3D model from which geologic questions can be answered, but even more importantly, to provide a background conductivity needed to complete the 3D IP inversion of airborne EM data. We begin by modifying our pre-existing 1D frequency and time domain inversion codes to produce models that have more lateral continuity. The results are useful in their own right but we have also found that 1D analysis is often very effective in bringing to light erroneous data, assisting in estimating noise floors, and providing some starting information for developing a background model for the 3D EM inversion. Here we show some results from our Laterally Constrained Inversion (LCI) framework. The recovered conductivity models seem to agree on the general location of the kimberlite pipes but disagree on the geometry and conductivity values at depth. The complete 3D inversions in time and frequency, needed to resolved these issues, are currently in progress.
DS200912-0472
2009
Marcheggiani-Croden, V.Marcheggiani-Croden, V., Hunt, L., Stachel, T., Muehlenbachs, K., Eichenberg, D.Diavik boart - unrelated to gem diamond and fibrous coats?37th. Annual Yellowknife Geoscience Forum, Abstracts p. 81-2.Canada, Northwest TerritoriesBoart diamond
DS201212-0319
2012
Marcheggliani-Croden, V.Hunt, L., Marcheggliani-Croden, V., Stachel, T., Muehlenbachs, K., Eichenberg, D.Polycrystalline and fibrous diamonds from the Diavik mine, Canada.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractCanada, Northwest TerritoriesDeposit - Diavik
DS201802-0252
2017
Marchenko, E.I.Marchenko, E.I., Eremin, N.N., Bychkov, A.Y., Grechanovskii, A.E.Ca and Mg perovskite phases in the Earth's mantle as a probable reservoir of Al: computer simulated evidence.Moscow University Geology Bulletin, Vol. 72, 5, pp. 299-304.Mantleperovskite

Abstract: Semi-empirical and quantum chemical studies of Al atom energy in CaSiO3 and MgSiO3 with the perovskite-type structure at pressures and temperatures of the Earth’s mantle are reported. The phase diagram for CaSiO3 is reproduced and refined. Probable mechanisms of Al incorporation in the structures studied are considered. According to the results of the calculations, Al is preferably incorporated into MgSiO3, rather than into CaSiO3. Evaluation of the isomorphic capacity of perovskite phases in relation to Al shows that the Al content in MgSiO3 may reach 2.4 mol % at 120 GPa and 2400 K. CaSiO3 cannot be a source of Al atoms in the Earth’s mantle.
DS202004-0537
2020
Marchenko, E.I.Tamarova, A.P., Marchenko, E.I., Bobrov, A.V., Eremin, N.N., Zinovera, N.G., Irifune, T., Hirata, T., Makino, Y.Interphase REE partitioning at the boundary between the Earth's transition zone and lower mantle: evidence from experiments and atomistic modeling.Minerals MDPI, Vol. 10, 10030262 14p. PdfMantleREE

Abstract: Trace elements play a significant role in interpretation of different processes in the deep Earth. However, the systematics of interphase rare-earth element (REE) partitioning under the conditions of the uppermost lower mantle are poorly understood. We performed high-pressure experiments to study the phase relations in key solid-phase reactions CaMgSi2O6 = CaSiO3-perovskite + MgSiO3-bridgmanite and (Mg,Fe)2SiO4-ringwoodite = (Mg,Fe)SiO3-bridgmanite + (Mg,Fe)O with addition of 1 wt % of REE oxides. Atomistic modeling was used to obtain more accurate quantitative estimates of the interphase REE partitioning and displayed the ideal model for the high-pressure minerals. HREE (Er, Tm, Yb, and Lu) are mostly accumulated in bridgmanite, while LREE are predominantly redistributed into CaSiO3. On the basis of the results of experiments and atomistic modeling, REE in bridgmanite are clearly divided into two groups (from La to Gd and from Gd to Lu). Interphase REE partition coefficients in solid-state reactions were calculated at 21.5 and 24 GPa for the first time. The new data are applicable for interpretation of the trace-element composition of the lower mantle inclusions in natural diamonds from kimberlite; the experimentally determined effect of pressure on the interphase (bridgmanite/CaSiO3-perovskite) REE partition coefficients can be a potential qualitative geobarometer for mineral inclusions in super-deep diamonds.
DS202009-1632
2020
Marchenko, E.I.Iskrina, A., Spivak, A.V., Bobrov, A.V., Eremin, N.N., Marchenko, E.I., Dubrovinsky, L.S.Synthesis and crystal structures of new high-pressure phases CaAl2O4 and Ca2Al6O11.Lithos, Vol. 374-375, 6p. PdfMantlegarnet

Abstract: The phases of CaAl2O4 and Ca2Al6O11 were synthesized at 15 GPa and 1600 °C. Microprobe data gave formulae Ca1.003Al1.998O4 and Ca2.05Al5.97O11, on the basis of 4 and 11 oxygen atoms. The crystal structures have been refined by single-crystal X-ray diffraction. Orthorhombic unitcell parameters for CaAl2O4 are a = 8.8569(10) Å; b = 2.8561(4) Å; c = 10.2521(11) Å; V = 259.34(5) Å3; Z = 8 (space group Pnma). The Ca2Al6O11 phase was obtained for the first time. It crystallizes with a space group P42/mnm and has lattice parameters a = b = 11.1675(4) Å; c = 2.83180(10) Å; V = 353.16(2) Å3; Z = 2. A Raman spectrum was obtained for a new phase for the first time. Our results suggest that both studied phases are stable under the condition of the transition zone and can be considered as potential aluminum concentrators in the Earth's deep geospheres.
DS1986-0233
1986
Marchenko, E.Ya.Faizullin, R.M., Sadykov, I.S., Marchenko, E.Ya.A geologic and technological model of the carbonatite type of apatite oredepositsSoviet Geology and Geophysics, Vol. 27, No. 11, pp. 24-31RussiaCarbonatite, Apatite
DS1960-0296
1962
Marcher, M.V.Stearns, R.G., Marcher, M.V.Late Cretaceous and Subsequent Structural Development of The Northern Mississippi Embayment Area.Geological Society of America (GSA) Bulletin., Vol. 73, PP. 1387-1394.GlobalMid-continent
DS201112-1081
2010
Marchese, C.Vasconcellos, E.M.G., Lopes, A.P., Fischer, G., Marchese, C., Reis Neto, J.M.Microtomografia de raios x applicada ao estudo de inclusoes em diamantes.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 44-45.South America, BrazilTomography - inclusions
DS201012-0473
2010
Marchesi, C.Marchesi, C., Griffin, W.L., Garrido, C.J., Bodinier, J-L., O'Reilly, S.Y., Pearson, N.J.Persistence of mantle lithospheric Re-Os signature during asthenospherization of the subcontinental lithospheric mantle: insights in situ sulphides....Contributions to Mineralogy and Petrology, Vol. 159, 3, pp. 315-330.Europe, SpainRonda peridotite
DS201312-0320
2013
Marchesi, C.Gonzalez-Jimienez, J.M., Marchesi, C., Griffin, W.L., Gutierrez-Narbona, R., Lorand, J-P., O'Reilly, S.Y., Garrido, C.J., Gervilla, F., Pearson, N.J., Hidas, K.Transfer of Os isotopic signatures from peridotite to chromitite in the subcontinental mantle: insights from in situ analysis of platinum-group and base metal minerals (Ojen peridotite massif, southern Spain.Lithos, Vol. 164-167, pp. 74-85.Europe, SpainChromitite
DS201312-0574
2013
Marchesi, C.Marchesi, C., Garrido, C.J., Bosch, D., Bodinier, J-L., Gervilla, F., Hidas, K.Mantle refertilization by melts of crustal derived garnet pyroxenite: evidence from the Ronda Peridotite massif, southern Spain.Earth and Planetary Interiors, Vol. 362, pp. 66-75.Europe, SpainRonda - pyroxenite. Melts
DS201412-0548
2014
Marchesi, C.Marchesi, C., Dale, C.W., Garrdo, C.J., Pearson, D.G., Bosch, D., Bodinier, J-L., Gervilla, F., Hidas, K.Fractionation of highly siderophile elements in refertilized mantle: implications for the Os isotope composition of basalts.Earth and Planetary Science Letters, Vol. 400, pp. 33-44.MantleRonda peridotite
DS201610-1850
2016
Marchesi, C.Chetoumani, K., Bondinier, J-L., Garrido, C.J., Marchesi, C., Amri, I., Targusiti, K.Spatial variability of pyroxenite layers in the Beni Bousera orogenic peridotite ( Morocco) and implications for their origin.Comptes Rendus Geoscience, in press available 11p.Africa, MoroccoPeridotite

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

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

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

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

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

Abstract: Subduction-Transform Edge Propagator (STEP) faults are the locus of continual lithospheric tearing at slab edges, resulting in sharp changes in the lithospheric and crustal thickness and triggering lateral and/or near-vertical mantle flow. However, the mechanisms at the lithospheric mantle scale are still poorly understood. Here, we present the microstructural study of olivine-rich lherzolite, harzburgite and wehrlite mantle xenoliths from the Oran volcanic field (Tell Atlas, NW Algeria). This alkali volcanic field occurs along a major STEP fault responsible for the Miocene westward slab retreat in the westernmost Mediterranean. Mantle xenoliths provide a unique opportunity to investigate the microstructures in the mantle section of a STEP fault system. The microstructures of mantle xenoliths show a variable grain size ranging from coarse granular to fine-grained equigranular textures uncorrelated with modal variations. The major element composition of the mantle peridotites provides temperature estimates in a wide range (790-1165?°C) but in general, the coarse-grained and fine-grained peridotites suggest deeper and shallower provenance depth, respectively. Olivine grain size in the fine-grained peridotites depends on the size and volume fraction of the pyroxene grains, which is consistent with pinning of olivine grain growth by pyroxenes as second phase particles. In the coarse-grained peridotites, well-developed olivine crystal preferred orientation (CPO) is characterized by orthorhombic and [100]-fiber symmetries, and orthopyroxene has a coherent CPO with that of olivine, suggesting their coeval deformation by dislocation creep at high-temperature. In the fine-grained microstructures, along with the weakening of the fabric strength, olivine CPO symmetry exhibits a shift towards [010]-fiber and the [010]- and [001]-axes of orthopyroxene are generally distributed subparallel to those of olivine. These data are consistent with deformation of olivine in the presence of low amounts of melts and the precipitation of orthopyroxenes from a melt phase. The bulk CPO of clinopyroxene mimics that of orthopyroxene via a topotaxial relationship of the two pyroxenes. This observation points to a melt-related origin of most clinopyroxenes in the Oran mantle xenoliths. The textural and geochemical record of the peridotites are consistent with interaction of a refractory harzburgite protolith with a high-Mg# melt at depth (resulting in the formation of coarse-grained clinopyroxene-rich lherzolite and wehrlite), and with a low-Mg# evolved melt in the shallow subcontinental lithospheric mantle (forming fine-grained harzburgite). We propose that pervasive melt-peridotite reaction - promoted by lateral and/or near-vertical mantle flow associated with lithospheric tearing - resulted in the synkinematic crystallization of secondary lherzolite and wehrlite and played a key effect on grain size reduction during the operation of the Rif-Tell STEP fault. Melt-rock reaction and secondary formation of lherzolite and wehrlite may be widespread in other STEP fault systems worldwide.
DS202008-1396
2020
Marchesi, C.Gonzales-Jiminez, J.M., Tassara, S., Schettino, E., Roque-Rosell, J., Farre-de-Pablo, J., Saunders, J.E., Deditius, A.P., Colas, V., Rovira-Medina, J.J., Guadalupe Davalos, M., Schilling, M., Jiminez-Franco, A., Marchesi, C., Nieto, F., Proenza, J.A., GerMineralogy of the HSE in the subcontinental lithospheric mantle - an interpretive review.Lithos, in press available, 44p. PdfMantleHSE

Abstract: The highly siderophile elements (HSE: Os, Ir, Ru, Rh, Pt, Pd, Re, Au) exist in solid solution in accessory base-metal sulfides (BMS) as well as nano-to-micron scale minerals in rocks of the subcontinental lithospheric mantle (SCLM). The latter include platinum-group minerals (PGM) and gold minerals, which may vary widely in morphology, composition and distribution. The PGM form isolated grains often associated with larger BMS hosted in residual olivine, located at interstices in between peridotite-forming minerals or more commonly in association with metasomatic minerals (pyroxenes, carbonates, phosphates) and silicate glasses in some peridotite xenoliths. The PGM found inside residual olivine are mainly Os-, Ir- and Ru-rich sulfides and alloys. In contrast, those associated with metasomatic minerals or silicate glasses of peridotite xenoliths consist of Pt, Pd, and Rh bonded with semimetals like As, Te, Bi, and Sn. Nanoscale observations on natural samples along with the results of recent experiments indicate that nucleation of PGM is mainly related with the uptake of HSE by nanoparticles, nanominerals or nanomelts at high temperature (> 900?°C) in both silicate and/or sulfide melts, regardless of the residual or metasomatic origin of their host minerals. A similar interpretation can be assumed for gold minerals. Our observations highlight that nanoscale processes play an important role on the ore-forming potential of primitive mantle-derived magmas parental to magmatic-hydrothermal deposits enriched in noble metals. The metal inventory in these magmas could be related with the physical incorporation of HSE-bearing nanoparticles or nanomelts during processes of partial melting of mantle peridotite and melt migration from the mantle to overlying continental crust.
DS1990-0180
1990
Marchesi, S.Beccaluva, L., Coltori, M., Marchesi, S.Lithospheric oceanic mantle beneath the Canary Islands: evidence from ultramafic xenoliths from LanzaroteTerra, Abstracts of International Workshop Orogenic Lherzolites and Mantle Processes, Vol. 2, December abstracts p. 125GlobalBasanite, Alkaline rocks
DS1991-1055
1991
Marchetto, M.Mariano, A.N., Marchetto, M.Serra Negra and Salitre-carbonatite alkaline igneous complexFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 75-82BrazilCarbonatite, Alkaline rocks
DS1992-0994
1992
Marchev, P.Marchev, P., et al.Petrology of neogene basanites and included ultramafic xenoliths of the Moesian Platform north Bulgaria.Neues Jahrbuch Miner. Abh., Vol. 164, No. 2-3, pp. 113-137.GlobalXenoliths, Basanites
DS201412-0549
2014
Marchi, S.Marchi, S., Bottke, W.F., Elkins-Tanton, M., Bierhaus, K., Wuennemann, A., Morbidelli, Kring, D.A.Wide spread mixing and burial of Earth's Hadean crust by asteroid impacts.Nature, Vol. 511, July 31, pp. 578-582.GlobalGeochronology - zircons
DS201710-2252
2017
Marchi, S.O'Neill, C., Marchi, S., Zhang, S., Bottke, W.Impact driven subduction on the Hadean Earth.Nature Geoscience, Vol. 10, 10, pp. 793-797.Mantlesubduction

Abstract: Impact cratering was a dominant geologic process in the early Solar System that probably played an active role in the crustal evolution of the young terrestrial planets. The Earth’s interior during the Hadean, 4.56 to 4 billion years ago, may have been too hot to sustain plate tectonics. However, whether large impacts could have triggered tectonism on the early Earth remains unclear. Here we conduct global-scale tectonic simulations of the evolution of the Earth through the Hadean eon under variable impact fluxes. Our simulations show that the thermal anomalies produced by large impacts induce mantle upwellings that are capable of driving transient subduction events. Furthermore, we find that moderate-sized impacts can act as subduction triggers by causing localized lithospheric thinning and mantle upwelling, and modulate tectonic activity. In contrast to contemporary subduction, the simulated localized subduction events are relatively short-lived (less than 10?Myr) with relatively thin, weak plates. We suggest that resurgence in subduction activity induced by an increased impact flux between 4.1 and 4.0 billion years ago may explain the coincident increase in palaeointensity of the magnetic field. We further suggest that transient impact-driven subduction reconciles evidence from Hadean zircons for tectonic activity with other lines of evidence consistent with an Earth that was largely tectonically stagnant from the Hadean into the Archaean.
DS1989-1509
1989
Marchildon, N.Trcienski, W.E., Marchildon, N.Kyanite-garnet bearing Cambrian rocks and Grenvilleg ranulites from theAyer's Cliff, Quebec, Canada,lamprophyre dike suite: deep crustal fragmentsGeology, Vol. 17, No. 7, July pp. 637-640QuebecLamprophyre
DS1993-0548
1993
Marchildon, N.Girard, R., Birkett, T., Moorhead, J., Marchildon, N.Geologie de la region de Press ClovaQuebec Department of Mines, MB 93-04, 54p.QuebecGeology
DS1992-0125
1992
Marchilfon, N.Birkett, T.C., Girard, R., Moorhead, J., Marchilfon, N.Carte geologique de la Province Grenville a l'est de l'axe LouvicourtVald'Or Senneterre.Quebec Department of Mines, MB 92-15, 15p.QuebecMap - geology
DS2001-0169
2001
Marcia, K.Challis, J., Marcia, K.The Star kimberlite 2001Saskatchewan Open House abstracts, Nov. p.55.SaskatchewanNews item, Shore Gold
DS2003-0651
2003
Marcia, K.Jellicoe, B.C., Zonnenveld, J.P., Marcia, K.Discovery and evolution of exploration methods at the Fort a la Corne kimberlite fieldGeological Association of Canada Annual Meeting, Abstract onlySaskatchewanTechniques
DS200412-0910
2003
Marcia, K.Jellicoe, B.C., Zonnenveld, J.P., Marcia, K.Discovery and evolution of exploration methods at the Fort a la Corne kimberlite field, Saskatchewan.Geological Association of Canada Annual Meeting, Abstract onlyCanada, SaskatchewanTechniques
DS2002-0993
2002
Marcia, K.Y.Marcia, K.Y., Chalis, J.The Diamondiferous Star kimberlite - a completely preserved kimberlite volcanoGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.73., p.73.SaskatchewanGeochemistry - petrology
DS2002-0994
2002
Marcia, K.Y.Marcia, K.Y., Chalis, J.The Diamondiferous Star kimberlite - a completely preserved kimberlite volcanoGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.73., p.73.SaskatchewanGeochemistry - petrology
DS2003-1566
2003
Marcia, K.Y.Zonneveld, J.P., Kjarsgaard, B.A., Harvey, S.E., Marcia, K.Y., McNeil, D.Sedimentologic and stratigrahic constraints on emplacement of the Star kimberlite, east8 Ikc Www.venuewest.com/8ikc/program.htm, Session 1, AbstractSaskatchewanGeology, economics, Deposit - Star
DS200412-2238
2003
Marcia, K.Y.Zonneveld, J.P., Kjarsgaard, B.A., Harvey, S.E., Marcia, K.Y., McNeil, D., Heaman, L.M., White, D.J.Sedimentologic and stratigrahic constraints on emplacement of the Star kimberlite, east central Saskatchewan.8 IKC Program, Session 1, AbstractCanada, SaskatchewanGeology, economics Deposit - Star
DS202008-1382
2020
Marcon, V.H.Conceicao, R.V., Marcon, V.H., Souza, M.R.W., Carniel, L.C., Quinteiro, R.V.S., Rovani, P., Mizusaki, A.M.P., Spitzenberger, M.S.Carbonatite/lamproite liquid imissibility in the Earth's mantle through the nefeline-diopside-kalsilite+-CO2, CH4, H2O diagram.Goldschmidt 2020, 1p. AbstractMantlelamproite

Abstract: The presence and speciation of volatile C-H-O elements in the silicate systems play an important role in the genesis of magmas on the Earth’s mantle, due to the fact that these elements, mainly in the form of H2O, CO2, CH4 and CxHy, decrease the solidi temperatures of source rocks, making magmatism possible in Earth’s present day thermal conditions [1]. Among those elements, carbon is the only element that changes its valence according to the oxygen fugacity (fO2) conditions of the environment, resulting in different speciation, as: CO3 -2, CO2, Cgraphite/diamond, CH4 or heavier hydrocarbons. In the present work, we are determining phase stability of minerals, water, CO2 and CH4 in the system Nefeline-Kalsilite-Diopside. Our experiments are conducted under 4.0 GPa and temperatures up to 1300°C, using a 1000 tonf hydraulic press coupled with toroidal chambers. Preliminary experiments performed at 1300°C and 4.0GPa (initial composition in the Olivine-Quartz- Kalsalite/Nepheline system: 40mol% Ol90, 40mol% Nph50Kls50 and 20mol% Qz, PH2O,CO2=Ptotal) resulted in the formation of forsterite (Fo90) in equilibrium with phlogopite (Phl), melt and volatile phases (CO2 and CH4). Closer to the Diopside vertice, the addition of CO3 to the sample resulted in a imisibility of a carbonatitic and a silicatic melt, in which the carbonititic melt is enriched in sodium, while the silcate melt is enriched in potassium. Appart from that, experiments in different parts of the diagram suggest compositions from nephelinite-kalsilitite to lamproites composition for the silicate melt in equilibrium with diopside (solid solution with omphacite) and phlogopite. This work is a continuation of previous work in the anhydrous diagram and future works will provide the addition of CH4 as the volatile phase
DS201901-0072
2018
Marcondes, M.L.Santos, S.S.M., Marcondes, M.L., Justo, J.F., Assali, L.V.C.Stability of calcium and magnesium carbonates at Earth's lower mantle thermodynamic conditions.Earth and Planetary Science Letters, Vol. 506, pp. 1-7.Mantlegeodynamics

Abstract: We present a theoretical investigation, based on ab initio calculations and the quasi-harmonic approximation, on the stability properties of magnesium (MgCO3) and calcium (CaCO3) carbonates at high temperatures and pressures. The results indicate that those carbonates should be stable in the Earth's lower mantle, instead of dissociating into other minerals, in chemical environments with excess of SiO2, MgO, or MgSiO3. Therefore, considering the lower mantle chemical composition, consisting mostly of the MgSiO3 and MgO minerals, calcium and magnesium carbonates are the primary candidates as carbon hosts in that region. For the thermodynamic conditions of the mantle, the results also indicate that carbon should be primarily hosted on MgCO3, contrasting with what was found by other theoretical studies, which neglected temperature effects. Finally, the results indicate that carbon, in the form of free CO2, is unlikely in the lower mantle.
DS1991-0157
1991
Marcotte, D.Bourgault, G., Marcotte, D.Multivariable variogram and its application to the linear model ofcoregionalizationMath. Geol, Vol. 23, No. 7, pp. 899-928GlobalGeostatistics, Variograms
DS1991-1049
1991
Marcotte, D.Marcotte, D.Cokriging with MatlabComputers and Geosciences, Vol. 17, No. 9, pp. 1265-1280GlobalComputer, Program -Matlab
DS1992-0150
1992
Marcotte, D.Bourgault, G., Marcotte, D., Legendre, P.The multivariate (Co) variogram as a spatial weighting function in classification methodsMathematical Geology, Vol. 24, No. 4, pp. 463-478GlobalComputer, cobalt, Program -Multivariate variograM.
DS1992-1224
1992
Marcotte, D.Posa, D., Marcotte, D.Robustness of kriging weights to non-bias conditionsMathematical Geology, Vol. 24, No. 7, pp. 759-774GlobalGeostatistics, Kriging
DS1995-0068
1995
Marcotte, D.Asli, M., Marcotte, D.Comparison of approaches to spatial estimation in a bivariate contextMathematical Geology, Vol. 27, No. 5, pp. 641-658OntarioGeostatistics, Volcanics
DS1995-1166
1995
Marcotte, D.Marcotte, D.Generalized cross validation for covariance model selectionMathematical Geology, Vol. 27, No. 5, pp. 659-672GlobalGeostatistics
DS1997-0731
1997
Marcotte, D.Marcotte, D., Groleau, P.A simple and robust log normal estimatorMath. Geol, Vol. 29, No. 8, Nov. pp. 993-1010GlobalComputer, Lognormal, geostatistics
DS201012-0324
2010
Marcotte, D.Ji, S., Quia,S.S., Marcotte, D.Lam parameters of common rocks in the Earth's crust and upper mantle.Journal of Geophysical Research, Vol. 115, B6, B06314.MantleGeophysics - seismics
DS1992-0995
1992
Marcotte, D.L.Marcotte, D.L., Hardwicke, C.D., Nelson, J.B.Automated interpretation of horizontal magnetic gradient profile dataGeophysics, Vol. 57, No. 2, February pp. 288-295GlobalGeophysics, Magnetics
DS2002-0608
2002
MarcouxGrancea, L., Bailly, L., Leroy, Banks, Marcoux, MilisiFluid evolution in the Baia Mare epithermal gold/polymetallic district, Inner CarpathiansMineralium deposita, RomaniaGold, copper, zinc, Deposit - Baia Mare
DS1993-0972
1993
Marcoux, E.Marcoux, E., Milesi, J.P.Lead isotope signature of Early Proterozoic ore deposits in Western Africa:comparison with gold deposits in French GuianaEconomic Geology, Vol. 88, No. 7, November pp. 1862-1879West AfricaGeochronology, Deposits -regional geology
DS1990-0981
1990
Marcus, J.Marcus, J.Mining environment - California exampleEngineering and Mining Journal, Vol. 191, No. 7, July pp. 16E, G, I, J.CaliforniaMining, Environment -legal
DS1990-0982
1990
Marcus, J.Marcus, J.Mining environment -financial ratios for mine analysisEngineering and Mining Journal, Vol. 191, No. 9, September pp. 16CC, 16EE, 16GG, 16II, 16KKUnited StatesLegal, Economics -mining environment
DS1990-0983
1990
Marcus, J.Marcus, J.Mining environment -financial assurances for mine closure; a discussion Of the issuesEngineering and Mining Journal, Vol. 191, No. 8, August pp. 16E, g, i, kUnited StatesLegal, Mining environment
DS1990-0984
1990
Marcus, J.Marcus, J.Mining enviornment- regulatory control of mining at the federal level, partoneEngineering and Mining Journal, Vol. 191, No. 6, June p. 16U, W, Y, Z, 16AA, BB.United StatesMining, Environment
DS1996-0885
1996
Marcus, J.J.Marcus, J.J.A long needed tome, , ,the mining environmental handbook.BriefdescriptionEngineering and Mining Journal, Vol. 197, No. 10, Oct. pp. 37, 39, 40, 42United StatesEnvironment, Mining industry book
DS1997-0732
1997
Marcus, J.J.Marcus, J.J.Mining environmental handbookImperial College Press, SummerGlobalBook - ad, Environment
DS202106-0958
2021
Mare, E.R.Mikhail, S., Rinaldi, M., Mare, E.R., Sverjensky, D.A.A genetic metasomatic link between eclogitic and peridotitc diamond inclusions.Geochemical Perspectives Letters, Vol. 17, pp. 33-38. pdfMantlediamond inclusions

Abstract: Diamond inclusions sample the otherwise inaccessible archive of Earth’s deep interior. The geochemical and petrological diversity of diamond inclusions reflects either pre-metasomatic upper mantle heterogeneity or metasomatism coeval with diamond formation. We focus on the origin of lithospheric garnet and clinopyroxene inclusions by simulating metasomatic reactions between eclogitic fluids and mantle peridotites at 5 GPa, 1000 °C, and across a range of redox conditions (logfO2?=?-1 to -6 ?FMQ). Our results demonstrate that fluid-rock interaction can result in the formation of eclogitic, websteritic, and peridotitic silicates from a single fluid during a single diamond-forming metasomatic event. Ergo, the petrogenesis of diamond and their inclusions can be syngenetic, and the petrological diversity of diamond inclusions can reflect metasomatism coeval with diamond formation. Furthermore, during the metasomatism, refractory peridotite can be converted to fertile websterite which could become a pyroxenitic mantle source for oceanic basalts.
DS1997-0733
1997
Mare, L.P.Mare, L.P., Thomas, R.J.Paleomagnetism and aeromagnetic modelling of the Mesoproterozoic Ntimbankulu Pluton, KwaZulu-Natal.Journal of African Earth Sciences, Vol. 25, No. 4, Nov. pp. 519-538.South AfricaDiapirs, Geophysics - palemagnetics
DS1960-0705
1966
Maree, B.D.Maree, B.D.Die Voorkoms Van Diamante Op Land En Onder die See Langs Die Weskus Van Suidelike Afrika.Tegnikon., Vol. 15, No. 4, PP. 149-159.South Africa, Southwest Africa, NamibiaLittoral Diamond Placers, Submarine
DS1993-0936
1993
Mareiche, A.M.Lukyanova, L.I., Derevyan, I.V., Mareiche, A.M., Dymnikov, W.G.On manifestation of Mesozoic ultra potassium magmatism and prospects of diamond bearing of Chernyshev Range district, Polar Urals.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 330, No. 5, June pp. 617-619.Russia, Commonwealth of Independent States (CIS), UralsAlkaline rocks, Ultrapotassic
DS1995-1124
1995
Mareichev, A.M.Lukyanova, L.I., Derevyanko, I.V., Mareichev, A.M., et al.Mesozoic ultrapotassic igneous rocks and the diamond potential of the Chernyshev Ridge area, Polar Urals.Doklady Academy of Sciences Acad. Science Russia, Vol. 331, No. 5, May pp. 107-110.Russia, UralsAlkaline rocks, Deposit -Chernyshev Ridge area
DS1995-1125
1995
Mareichev, A.M.Lukyanova, L.I., Mareichev, A.M., Kuznetsov, G.P.Prospects for discovery of primary diamond deposits in the Urals and the eastern Russian PlatformMineral Resources of Russia, abstracts, Oct. 1994, pp. 19-23.Russia, UralsProspecting, Diamonds
DS2000-0614
2000
Marek, R.Marek, R.Paleozoic structures at the margin of Baltic Shield rvealed by new / reprocessed marine reflection seismicTectonophysics, Vol. 327, No. 3-4, Dec.15, pp. 293-310.Scandinavia, Baltic ShieldGeophysics - seismic, Tectonics
DS1975-0237
1976
Marenga, B.S.I.Baldock, J.W., Hepworth, J.V., Marenga, B.S.I.Gold, Base Metals and Diamonds in BotswanaEconomic Geology, Vol. 71, No. 1, PP. 139-152;BotswanaKimberlite, Orapa
DS1975-0455
1977
Marengwa, B.S.I.Baldock, J.W., Hepworth, J.V., Marengwa, B.S.I.Resource Inventory of BotswanaBotswana Geological Survey, Vol. 4, 69P. PP. 49-57. (DIAMONDS).BotswanaKimberlite, Diamond Prospecting
DS1981-0282
1981
Marensi de moura, O.J.Marensi de moura, O.J., et al.Gemas de Minas GeraisBelo Horizonte: Metannig, BrazilKimberlite, Kimberley, Janlib, Gemology
DS1996-0886
1996
Mares, V.M.Mares, V.M.Kinematics of the Kimberley Arc: linear indicators of movement direction of rocks and their tectonics....Geological Society of Australia 13th. Convention held Feb., No. 41, abstracts p.267.AustraliaTectonics -lineaments, Kimberley Arc
DS200412-0908
2003
Marescahl, J.C.Jaupart, C., Marescahl, J.C.Constraints on crustal heat production from heat flow data.Treatise on Geochemistry, Holland Editor, Volume 3, pp. 65-84.MantleGeothermometry
DS200512-0038
2004
Marescahl, J.C.Audet, P., Marescahl, J.C.Anisotropy of the flexural response of the lithosphere in the Canadian Shield.Geophysical Research Letters, Vol. 31, 20, Oct. 28, DOI 10.1029/2004GLO21080Canada, Northwest Territories, Alberta, Saskatchewan, OntarioGeophysics
DS1990-0216
1990
Maresch, W.V.Bocchio, R., De Capitani, L., Liborio, G., Maresch, W.V., MottanaThe eclogite bearing series of Isla Margarita, Venezuela: geochemistry of metabasic lithologies in the la Rinconada and Juan Griego GroupsLithos, Vol. 25, No. 1-3, November pp. 55-70VenezuelaEclogites, Geochemistry
DS2002-0555
2002
Maresch, W.V.Gerya, T.V., Maresch, W.V., Willner, A.P.Lithospheric detachment and slab breakoff under the Variscan collisional orogen: keys to the origin of diamond bearing crustal rocks in the Bohemmian Massif.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.218.Europe, GermanyDiamond - bearing quartzo-feldspathic
DS2002-0556
2002
Maresch, W.V.Gerya, T.V., Perchuk, L.L., Maresch, W.V., Willner, A.P., Van ReenenThermal regime and gravitational instability of multi layered continental crust:European Journal of Mineralogy, Vol. 14,4,pp. 687-700.MantleUHP - not specific to diamonds
DS200412-0653
2003
Maresch, W.V.Gerya, T.V., Uken, R., Reinhardt, J., Watkeys, M.K., Maresch, W.V., Clarke, B.M.Cold fingers in a hot magma: numerical modeling of country rock diapirs in the Bushveld Complex, South Africa.Geology, Vol. 31, 9, pp. 753-6.Africa, South AfricaDiapirism, magmatism, plumes, subduction zones
DS200612-1073
2005
Maresch, W.V.Perchuk, A.L., Burchard, M., Maresch, W.V., Schertl, H-P.Fluid mediated modification of garnet interiors under ultrahigh pressure conditions.Terra Nova, Vol. 17, 6, pp. 545-553.MantleUHP
DS201012-0573
2009
Maresch, W.V.Perchuk, A.L., Davydova, V.V., Burchard, M., Maresch, W.V., Schertl, H.P., Yapaskurt, V.O., Safonov, O.G.Modification of mineral inclusions in garnet under high pressure conditions: experimental simulation and application to carbonate silicate rocks of KokchetetavRussian Geology and Geophysics, Vol. 50, 12, pp. 1153-1168.RussiaMineralogy
DS1996-0695
1996
MareschalJones, A.G., Eaton, D.W., White, D., Bostock, M., MareschalGeophysical measurements for lithospheric parametersGeological Survey of Canada, LeCheminant ed, OF 3228, pp. 243-250.Canada, mantleGeophysics -seismics, Lithosphere
DS1999-0733
1999
MareschalTelmat, H., Mareschal, J-C, Gariepy, C.The gravity field over Ungava Bay region from satellite altimitry and newland based data: implications geologyCanadian Journal of Earth Sciences, Vol. 36, No. 1, Jan. pp. 75-89.Quebec, Labrador, UngavaGeophysics - gravity
DS2000-0950
2000
MareschalTelmat, H., Mareschal, Gariepy, David, AntonukCrustal models of the eastern Superior Province, Quebec, derived from new gravity data.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.385-97.QuebecGeophysics - gravity, Tectonics - Superior
DS1989-0876
1989
Mareschal, J.C.LeQuentrec, M.F., Mareschal, J.C., Parphenuk, O.A finite element model of the thermal evolution of theKapuskasingstructureGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A103. (abstract.)OntarioTectonics, Kapuskasing Lithoprobe
DS1989-0934
1989
Mareschal, J.C.Mareschal, J.C., Hamdani, Y., Jessup, D.M.Downward continuation of heat flow dataTectonophysics, Vol. 164, No. 2-4, August 1, pp. 129-138GlobalMantle, Crust -heat flow
DS1989-0935
1989
Mareschal, J.C.Mareschal, J.C., Pinet, C., Gariepy, C., Jaupart, C., Bienfait, G., DallaNew heat flow density and radiogenic heat productiondat a in the Canadian Shield and the QuebecAppalachiansCanadian Journal of Earth Sciences, Vol. 26, No. 4, April pp. 845-852QuebecCraton, Heat Flow
DS1991-1050
1991
Mareschal, J.C.Mareschal, J.C.Downward continuation of heat flow density dat a and thermal regime In eastern CanadaTectonophysics, Vol. 194, No. 4, August 10, pp. 349-356AppalachiaGeothermometry, Heat flow
DS1991-1051
1991
Mareschal, J.C.Mareschal, J.C., Gliko, A.Lithospheric thinning uplift, and heat flow preceding riftingTectonophysics, Vol. 197, No. 2-4, November pp. 117-126MantleGeodynamics, Rift system, heat flow
DS1992-1382
1992
Mareschal, J.C.Shen, P.Y., Wang, K., Beltrami, H., Mareschal, J.C.Paleoclimate change and heat flow density inferred from temperate dat a In the Superior province of the Canadian ShieldPaleogeography, paleoclimatology, paleoecology, Vol. 98, No. 2-4, December pp. 143-166Canada, OntarioHeat flow, Paleoclimates
DS1997-1148
1997
Mareschal, J.C.Telmat, H., Antonuk, C.N., Mareschal, J.C.Gravity modelling along a lithoprobe seismic traverse, northern Grenvilleprovince, western Quebec.Canadian Journal of Earth Sciences, Vol. 34, pp. 127-34.Quebec, LabradorGrenville area
DS1998-0688
1998
Mareschal, J.C.Jaupert, C., Mareschal, J.C., Davaille, A.Heat flow and thickness of the lithosphere in the Canadian ShieldJournal of Geophysical Research, Vol. 103, No. 7, Jul. 10, pp. 15269-86.Northwest Territories, Manitoba, Saskatchewan, AlbertaHeat flow, Mantle
DS1998-0941
1998
Mareschal, J.C.Mareschal, J.C., Gillou-Frottier, L., Cheng, L.Z.Heat flow in the Trans Hudson OrogenGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A117. abstract.ManitobaGeothermometry - heat flow, Trans Hudson Orogen
DS1998-1459
1998
Mareschal, J.C.Telmat, H., Mareschal, J.C., Gariepy, C., David, J.Crustal models of the northern Superior Province, Quebec, derived from new gravity data.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A183. abstract.QuebecGeophysics - gravity, Nemiscau, la Grande regions
DS1999-0335
1999
Mareschal, J.C.Jaupart, C., Mareschal, J.C.The thermal structure and thickness of continental rootsLithos, Vol. 48, No. 1-4, Sept. pp. 93-114.MantleGeothermometry, Craton
DS1999-0732
1999
Mareschal, J.C.Telmat, H., Mareschal, J.C., Gariepy, C.The gravity field over the Ungava Bay region from satellite altimetry and new land based data:Canadian Journal of Earth Sciences, Vol. 36, pp. 75-89.Quebec, Labrador, Ungavageophysics - seismic, Leaf Bay - George River
DS1999-0781
1999
Mareschal, J.C.Wang, Y., Mareschal, J.C.Elastic thickness of the lithosphere in the central Canadian shieldGeophysical Research Letters, Vol. 26, No. 19, Oct. 1, pp. 3033-36.Ontario, Manitoba, SaskatchewanLithosphere, Crust
DS2000-0615
2000
Mareschal, J.C.Mareschal, J.C., Jaupart, Gariepy, Cheng et al.Heat flow and deep thermal structure near the southeastern edge of the Canadian Shield.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.399-414.QuebecGeothermometry, Tectonics
DS2002-0194
2002
Mareschal, J.C.Bourlon, E., Mareschal, J.C., Roest, W.R., Telmat, H.Geophysics correlations in the Ungava Bay areaCanadian Journal of Earth Science, Vol.39,5, May, pp.625-37.Quebec, Labrador, Baffin IslandGeophysics - gravity, magnetics, Tectonics
DS2002-0284
2002
Mareschal, J.C.Cheng, L.Z., Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., RadigonSimultaneous inversion of gravity and heat flow data: constraints on thermal regimeJournal of Geodynamics, Vol. 34, 1, pp. 11-30.Ontario, ManitobaGeothermometry, Lithosphere - Abitibi subprovince, Thompson Belt
DS2002-1355
2002
Mareschal, J.C.Rolandone, F., Jaupart, C., Mareschal, J.C., Gariepy, C., Bienfait, G., CarbonneSurface heat flow, crustal temperatures and mantle heat flow in the Proterozoic TransJournal of Geophysical Research, Vol. 107, No. 12, Dec. 12, 10.1029/2001JB000698Northwest Territories, Alberta, Saskatchewan, OntarioGeothermometry, Heat flow - tectonics
DS2003-1177
2003
Mareschal, J.C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gariepy, C., Bienfait, G., CarbonneSurface heat flow, crustal temperatures and mantle heat flow in the Proterozoic TransJournal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001JB000698OntarioGeothermometry
DS2003-1178
2003
Mareschal, J.C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., LapointeHeat flow in the western Superior province of the Canadian ShieldJournal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003GLO17386Ontario, Manitoba, SaskatchewanGeothermometry
DS200412-1224
2004
Mareschal, J.C.Mareschal, J.C., Jaupart, C.Variations of surface heat flow and lithospheric thermal structure beneath the North American craton.Earth and Planetary Science Letters, Vol. 223, 1-2, pp. 65-77.Canada, Northwest TerritoriesGeothermometry
DS200412-1682
2003
Mareschal, J.C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gariepy, C., Bienfait, G., Carbonne, C., Lapointe, R.Surface heat flow, crustal temperatures and mantle heat flow in the Proterozoic Trans Hudson Orogen, Canadian Shield.Journal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001 JB000698Canada, OntarioGeothermometry
DS200412-1683
2003
Mareschal, J.C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., Lapointe, R.Heat flow in the western Superior province of the Canadian Shield.Journal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003 GLO17386Canada, Ontario, Manitoba, SaskatchewanGeothermometry
DS200512-0686
2005
Mareschal, J.C.Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., Fowler, C.M., Bienfait, G., Carbonne, C., Lapointe, R.Heat flow, thermal regime, and elastic thickness of the lithosphere in the Trans-Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 517-532.Canada, Northwest TerritoriesGeothermometry
DS200512-0846
2004
Mareschal, J.C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Rolandone, F., Bienfait, G.Heat flow in the Nipigon arm of the Keweenawan Rift, northwestern Ontario, Canada.Geophysical Research Letters, Vol. 31, 15,, L15607, DOI 1029/2004 GL020159Canada, OntarioGeothermometry
DS200612-1078
2006
Mareschal, J.C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Bienfait, G.Crustal heat production in the Superior Province Canadian Shield and in North America inferred from heat flow data.Journal of Geophysical Research, Vol. 111, B4, B04401.Canada, Ontario, ManitobaGeothermometry
DS200612-1079
2006
Mareschal, J.C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Shapiro, N.M.Upper mantle velocity temperature conversion and composition determined from seismic refraction and heat flow.Journal of Geophysical Research, Vol. 111, B7 B07301MantleGeophysics - seismics
DS200612-1080
2006
Mareschal, J.C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Shapiro, N.M.Upper mantle velocity temperature conversion and composition determined from seismic.Journal of Geophysical Research, Vol. 111, B7, July 6, B07301, 14p.Mantle, Canada, OntarioGeophysics - seismics, Superior Province
DS200912-0499
2009
Mareschal, J.C.Michaut, C., Jaupart, C., Mareschal, J.C.Thermal evolution of cratonic roots.Lithos, Vol. 109, 1-2, pp. 47-60.MantleGeothermometry
DS1991-1355
1991
Mareschal, J-C.Pinet, C., Jaupart, C., Mareschal, J-C., Gariepy, C., Bienfait, G.Heat flow and structure of the lithosphere in the eastern Canadian shieldJournal of Geophysical Research, Vol. 96, No. B12, November 10, pp. 19, 941-19, 963OntarioHeat flow, Crust, greenstone belts
DS200612-0120
2005
Mareschal, J-C.Benn, K., Mareschal, J-C., Condie, K.C.Seismic reflection profiles across Archean Cratons.Benn, K., Mareschal, J-C., Condie, K.C. Archean Geodynamics and Environments, AGU Geophysical Monograph, No. 164, p. 264 - foldouts 1 and 2MantleGeophysics - seismic reflection profiles Archean craton
DS200612-0865
2005
Mareschal, J-C.Mareschal, J-C., Jaupart, C.Archean thermal regime and stabilization of the Craton.Benn, K., Mareschal, J-C., Condie, K.C. Archean Geodynamics and Environments, AGU Geophysical Monograph, No. 164, pp. 61-74.MantleGeothermometry
DS200612-0866
2006
Mareschal, J-C.Mareschal, J-C., Jaupart, C., Perry, H.K.C.Crustal evolution in North America recorded in heat production.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 12, abstract only.Mantle, North AmericaGeothermometry
DS200612-1081
2006
Mareschal, J-C.Perry, H.K.C., Jaupart, C., Mareschal, J-C., Bienfait, G.Crustal heat production in the Superior Province, Canadian Shield, and in North America.Journal of Geophysical Research, Vol. 111, No. B4, B04401Canada, Ontario, Manitoba, Saskatchewan, AlbertaGeothermometry
DS200612-1082
2006
Mareschal, J-C.Perry, H.K.C., Mareschal, J-C., Jaupart, C.Variations of strength and localized deformation in cratons: the 1.9 Ga Kapuskasing Uplift, Superior Province, Canada.Earth and Planetary Science Letters, In press - availableCanada, Ontario, ManitobaGeothermometry, craton, structural zone
DS201012-0437
2010
Mareschal, J-C.Levy, F., Jaupart, C., Mareschal, J-C., Bienfait, G., Limare, A.Low heat flux and large variations of lithospheric thickness in the Canadian Shield.Journal of Geophysical Research, Vol. 115, B6, B06404.CanadaGeophysics - seismics
DS201112-0479
2010
Mareschal, J-C.Jaupart, C., Mareschal, J-C.Heat generation and transport in the Earth.cambridge.org/us/earth, 978-0-521-89488-3 476p. $ 75.00GlobalBook - advertisement
DS201112-0883
2011
Mareschal, J-C.Roy, S., Mareschal, J-C.Constraints on the deep thermal structure of the Dharwar craton, India, from heat flow, shear wave velocities and mantle xenoliths.Journal of Geophysical Research, Vol. 116, B2, B02409.IndiaGeothermometry
DS201312-0575
2013
Mareschal, J-C.Mareschal, J-C., Jaupart, V.Radiogenic heat production, thermal regime and evolution of continental crust.Tectonophysics, Vol. 609, pp. 524-534.MantleGeothermometry
DS201609-1723
2016
Mareschal, J-C.Jaupart, C., Mareschal, J-C., Iarotsky, L.Radiogenic heat production in the continental crust.Lithos, Vol. 262, pp. 398-427.MantleThermometry

Abstract: Heat flow and heat production data complement seismic information and provide strong constraints on crustal composition, thickness and evolution. They have helped understand the nature of the Mohorovicic discontinuity and the variations in seismic velocities below the Moho. Notably, heat flow studies have delineated the vertical distribution of heat producing elements throughout the crust and in the upper most mantle lithosphere. Analysis of global data sets on heat flow and crustal thickness demonstrate that there is no correlation between these two variables. This is due to the large spatial variations in crustal composition and heat production that exist within a single geological province. For a given crustal thickness, the Moho temperature varies within a wide range (˜ 300 K) depending on surface heat flux and crustal heat production. Thus one cannot use generic models based on a “type” crustal column to calculate crustal geotherms. In stable regions, lower crustal temperatures depend on the amount and vertical distribution of heat producing elements in the crust. These temperatures determine the conditions of crustal stability and impose a limit on the maximum thickness of a stabilized crust.
DS201905-1048
2018
Mareschal, J-C.Jaupart, C., Mareschal, J-C., Roman, A.The formation of continental crust from a physics perspective.Geochemistry International, Vol. 56, 13, pp. 1289-1321.Mantlegeophysics

Abstract: The generation of crustal material and the formation of continental crust with a thickness of ˜40 km involve different physical mechanisms operating over different time-scales and length-scales. This review focusses on the building of a thick crustal assemblage and on the vertical dimension where the consequences of gravity-driven processes are expressed most clearly. Continental crustal material is produced by a sequence of crust and mantle mlelting, fractionation of basaltic melts and sinking of dense mafic cumulates. The repeated operation of these mechanisms over tens of million years leads to a thick stably stratified crust. We evaluate the main mechanisms involved from a physics perspective and identify the key controls and constraints, with special attention to thermal requirements. To form magma reservoirs able to process significant magma volumes and to allow the foundering of mafic cumulates, melt must be fed locally at rates that are larger than that of average crustal growth. This requires the temporary focussing of magmatic activity in a few centers. In some cases, foundering of dense cumulates does not go to completion, leaving a deformed residual body bearing tell-tale traces of the process. Crust must be thicker than a threshold value in a 30-45 km range for mafic cumulates to sink into the mantle below the crust. Once that threshold thickness has been reached, further additions lead to increase the proportion of felsic material in the crust at the expense of mafic lithologies which disappear from the crust. This acts to enhance radiogenic heat production in the crust. One consequence is that crustal temperatures can be kept at high values in times of diminished melt input and also when magmatic activity stops altogether, which may lead to post-orogenic intracrustal melting and differentiation. Another consequence is that the crust becomes too weak mechanically to withstand the elevation difference with neighbouring terranes, which sets a limit on crustal thickening. The thermal structure of the evolving crust is a key constraint on the overall process and depends strongly on radiogenic heat production, which is surely one of the properties that make continental crust very distinctive. In the Archean Superior Province, Canada, the formation of juvenile continental crust and its thermal maturation 2.7 Gy ago can be tracked quite accurately and reproduced by calculations relying on the wealth of heat flow and heat production data available there. Physical models of magma ascent and storage favour the formation of magma reservoirs at shallow levels. This suggests that crustal growth proceeds mostly from the top down, with material that gets buried to increasingly large depths. Vertical growth is accompanied by lateral spreading in two different places. Within the crust, magma intrusions are bound to extend in the horizontal direction. Deeper down, lateral variations of Moho depth that develop due to the focussing of magmatic activity get relaxed by lower crustal flow. This review has not dealt with processes at the interface between the growing crust and the mantle, which may well be where dikes get initiated by mechanisms that have so far defied theoretical analyses. Research in this particular area is required to further our understanding of continental crust formation.
DS1989-0936
1989
Mareschal, M.Mareschal, M.Electrical conductivity in the Kapuskasking upliftGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A103. (abstract.)OntarioTectonics, Kapuskasing Lithoprobe
DS1990-0985
1990
Mareschal, M.Mareschal, M.Electrical conductivity: the story of an elusive parameter, and of how it possibly relates to the Kapuskasing Uplift (Lithoprobe, Canada)Exposed cross sections of the Continental Crust, ed. M.H. Salisbury and, pp. 453-468OntarioKapuskasing zone, Tectonics
DS1991-1052
1991
Mareschal, M.Mareschal, M., Kurtz, R.D., Chouteau, M., Chakridi, R.A magnetotelluric survey on Manitoulin Island and Bruce Peninsula along Glimpce seismic line J: black shales mask the Grenville FrontGeophys. Journal of International, Vol. 104, pp. 173-183OntarioGeophysics -seismics, Magnetotelluric
DS1991-1132
1991
Mareschal, M.Mereu, R.F., Percival, J.A., Mareschal, M., Salisbury, M.H.Collaborative special project to identify seismic reflectors in high grade metamorphic rocks of the Kapuskasing UpliftCan. Cont. Drilling Project, August 40pOntarioGeophysics -seismics, Kapuskasing Zone
DS1992-0996
1992
Mareschal, M.Mareschal, M., Fyfe, W.S., Percival, J., Chan, T.Grain boundary graphite in Kapuskasing gneisses and implications for lower-crustal conductivityNature, Vol. 357, No. 6380, June 25, pp. 674-676OntarioRifting, Geophysics -conductivity
DS1993-0791
1993
Mareschal, M.Katsube, T.J., Mareschal, M.Petrophysical model of deep electrical conductors: graphite lining as A source and its disconnection due to upliftJournal of Geophysical Research, Vol. 98, No. B5, May 10, pp. 8019-8030MantleTectonics, Geophysics -electromagnetic conductors
DS1994-1101
1994
Mareschal, M.Mareschal, M., et al.A review of electromagnetic investigations in the Kapuskasing uplift and surrounding regions: key rocks.Canadian Journal of Earth Sciences, Vol. 31, No. 7, July pp. 1042-1051.OntarioGeophysics -electromagnetics, Tectonics -Kapuskasing uplift
DS1995-1167
1995
Mareschal, M.Mareschal, M., Kellett, R.L., Juntz, R.D., Ludden, J.N. Li.Archean cratonic roots, mantle shear zones and deep electrical SOURCE[ NatureNature, Vol. 375, No. 6527, May 11, pp. 134-136.MantleCraton, Geophysics
DS1995-1168
1995
Mareschal, M.Mareschal, M., Kellett, R.L., Kurtz, R.D., Ludden, JiArchean cratonic roots, mantle shear zones and deep electrical anisotropy.Nature, Vol. 375, No. 6527, May 11, pp. 134-136MantleCraton, Geophysics -seismics
DS1995-2129
1995
Mareschal, M.Zhang, P., Chouteau, M., Mareschal, M., Jurtz, R., HubertHigh frequency magnetotelluric investigation of crustal structure in north central Abitibi QuebecGeophy. Journal, Vol. 120, pp. 406-418QuebecLithoprobe - AMT, Abitibi greenstone belt
DS1996-1282
1996
Mareschal, M.Senechal, G., Mareschal, M., Hubert, C., Calvert, et al.Integrated geophysical interpretation of crustal structures in the northern Abitibi belt: seismics, ,Canadian Journal of Earth Sciences, Vol. 33, No. 9, Sept. pp. 1343-1362QuebecGeophysics - seismics, structure, Abitibi belt
DS200612-0867
2006
Mareschall, H.R.Mareschall, H.R., Altherr, R., Rupke, L.Squeezing out the slab - modelling the release of Li, Be and B during progressive high pressure metamorphism.Chemical Geology, in press available,MantleSubduction zone
DS1994-1069
1994
Mareychev, A.M.Lukyanova, L.I., Mareychev, A.M., et al.The first discovery of lamproite magmatism in the southern UralsDoklady Academy of Sciences, Vol. 325, No. 5, pp. 118-123.Russia, UralsMagmatism -lamproite, Lamprophyres
DS202107-1112
2021
Marfin, A.Marfin, A., Radomskaya, T.A., Ivanov, A.V., Belozerova, O.Y.U-Pb dating of apatite, titanite and zircon of the Kingash mafic-ultramafic massif, Kan terrane Siberia: from Rodinia break-up to the reunion of the Siberian craton.Journal of Petrology, Vol. 62, 6, EGAb049Russia, Siberiacratons

Abstract: The initial stage of Rodinia supercontinent break-up occurred at about 750?Ma. It preceded formation of the Irkutsk and Franklin Large Igneous Provinces (LIPs)at 712 ± 2?Ma to 739 ± 8?Ma. These LIPs were emplaced within the formerly connected Laurentian and Siberian cratons. The Kingash massif is located in the Precambrian Kan terrane in direct contact with the Siberian Craton at its southwestern boundary. It has been linked to an important suite of mafic-ultramafic intrusions which border the southern margin of the Siberian craton, and which have been inferred to belong to the Irkutsk LIP. The massif is also significant, because it hosts PGE-Cu-Ni rich mineralization and is the only large deposit in the region. However, despite numerous dating attempts, the age of the massif had not been resolved. A significant difficulty is post-magmatic recrystallization at amphibolite facies that affected the rocks of the massif. In this study we used U-Pb dating of zircon, titanite and apatite from rocks of the Kingash massif and cross-cutting granite and monzonite veins. The oldest igneous zircon grain of the Kingash massif analysed by LA-ICPMS yields an age of c. 750?Ma, taken as a tentative age of magmatism. Dating of multiple grains of metamorphic zircon by CA-ID-TIMS yielded 564.8 ± 2.2?Ma, which is in agreement with LA-ICPMS titanite ages 557 ± 19?Ma, 565 ± 35?Ma and 551 ± 17?Ma. Apatite of two different samples showed ages of 496.4 ± 7.9?Ma and 497.0 ± 1.8?Ma (LA-ICPMS), which are interpreted as the time when the terrane cooled below the closure temperature of apatite. Using our new data we suggest that at the time of the Irkutsk-Franklin LIP event the Kan terrane was a part of Rodinia, then it separated from either Siberia or Laurentia during the break-up of Rodinia and finally collided with Siberia at 560?Ma; the time of regional amphibole facies metamorphism.
DS202107-1103
2021
Marfin, A.E.Ivanov, A.V., Corfu, F., Kamenetsky, V.S., Marfin, A.E., Vladykin, N.V.207Pb-excess in carbonatitic baddeleyite as the result of Pa scavenging from the melt. ( Guli Siberian traps)Geochemical Perspectives Letters, Vol. 18, pp. 11-15. pdfRussia, Siberiacarbonatite

Abstract: For the last two decades, the end of the voluminous phase of eruptions of the Siberian Traps large igneous province has been constrained by a U-Pb date of discordant baddeleyite collected from the Guli carbonatite intrusion with the assumption that the discordance resulted from unsupported 207Pb. In this study we have re-analysed baddeleyite from the same intrusion and found two types of discordance: (1) due to 207Pb-excess, and (2) radiogenic lead loss from high U mineral inclusions. The former implies that baddeleyite is an efficient scavenger of protactinium during crystallisation, leaving the magma depleted in this element. Together with a published high precision U-Pb date of 252.24?±?0.08 Ma for the Arydzhansky Formation, our new date of 250.33?±?0.38 Ma for the Guli carbonatite constrains the total duration of the voluminous eruptions of the Siberian Traps LIP at 1.91?±?0.38 million years. The lower intercept of the (231Pa)/(235U) corrected discordance line yields a date of 129.2?±?65.0 Ma, which points to the widespread Early Cretaceous rifting in East and Central Asia.
DS202109-1474
2020
Marfin, A.E.Ivanov, A.V., Corfu, F., Kamenetsky, V.S., Marfin, A.E., Vladykin, N.V.207 Pb-excess in carbonatitic baddeleyite as the result of Pa scavenging from the melt.Geochemical Perspectives Letters, Vol. 18, pp. 11-15. pdfRussia, Siberiadeposit - Guli

Abstract: For the last two decades, the end of the voluminous phase of eruptions of the Siberian Traps large igneous province has been constrained by a U-Pb date of discordant baddeleyite collected from the Guli carbonatite intrusion with the assumption that the discordance resulted from unsupported 207Pb. In this study we have re-analysed baddeleyite from the same intrusion and found two types of discordance: (1) due to 207Pb-excess, and (2) radiogenic lead loss from high U mineral inclusions. The former implies that baddeleyite is an efficient scavenger of protactinium during crystallisation, leaving the magma depleted in this element. Together with a published high precision U-Pb date of 252.24?±?0.08 Ma for the Arydzhansky Formation, our new date of 250.33?±?0.38 Ma for the Guli carbonatite constrains the total duration of the voluminous eruptions of the Siberian Traps LIP at 1.91?±?0.38 million years. The lower intercept of the (231Pa)/(235U) corrected discordance line yields a date of 129.2?±?65.0 Ma, which points to the widespread Early Cretaceous rifting in East and Central Asia.
DS1991-1053
1991
Marfunin, A.S.Marfunin, A.S.Diamond sources: Russia #1International Gemological Symposium, June 20-24, 1991 Los Angeles, Gems and Gemology, Vol. 27, Spring, Program p. 3RussiaDiamond production-sources
DS1992-0997
1992
Marfunin, A.S.Marfunin, A.S.Diamond sources: Russia #2Gemological Institute of America, Proceedings Volume ed. A. Keller, p. 56. (abstract)RussiaEconomics, Diamond production
DS1995-1260
1995
Marfunin, A.S.Mineeva, R.M., Titkov, S.V., Marfunin, A.S., et al.EPR spectroscopy of Yakutian diamondsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 389.Russia, YakutiaDiamond morphology, Spectroscopy
DS1996-0548
1996
Marfunin, A.S.Gorshov, A.N., Titkov, S.V., Marfunin, A.S.The first finds of native chromium, nickel and alpha iron in carbonado from the Diamond deposits of Yakutia.Geochemistry International, Vol. 33, No. 1, Jan. 1, pp. 59-63.Russia, YakutiaCarbonado, Native chromium, nickel, iron
DS1998-0942
1998
Marfunin, A.S.Marfunin, A.S.Advanced mineralogySpringer, 490p. approx. $ 200.00GlobalBook - ad, Mineralogy - mantle, ocean, space
DS1999-0444
1999
Marfunin, A.S.Marfunin, A.S., Kononov, O.V., Shelementiev, Y.B.Diamond mineralogy, physics, Gemology and world market: state of the artMoscow University of Geol. Bulletin., Vol. 53, No. 5, pp. 53-66.RussiaDiamond geology - overview
DS200812-0338
2008
Marfunin, A.S.Fang, L., Kononov, O.V., Marfunin, A.S., Taraevich, A.V., Tarasavich, B.N.Development of a technique for IR spectroscopic determination of nitrogen content and aggregation degree in diamond crystals.Moscow University Geology Bulletin, Vol. 63, 4, pp. 281-284.TechnologyDiamond morphology
DS200412-1225
2003
Margerin, L.Margerin,L., Nolet, G.Multiple scattering of high frequency seismic waves in the deep Earth: PKP precursor analysis and inversion for mantle granulariJournal of Geophysical Research, Vol. 108, B11, ESE 9 10.1029/2003 JB002455MantleGeophysics - seismics
DS200612-0868
2006
Margerin, L.Margerin, L.Attenuation, transport and diffusion of scalar waves in textured random media.Tectonophysics, Vol. 416, 1-4, April 5, pp. 229-244.MantleGeophysics - seismics
DS2000-0616
2000
Marhsak, S.Marhsak, S., Karlstrom, K., Timmons, J.M.Inversion of Proterozoic extensional faults: an explanation for the pattern of Laramide and Rockies...Geology, Vol. 28, No.8, Aug. pp. 735-8.United States, CordilleraTectonics, Intracratonic deformation
DS201911-2545
2019
Maria, A.H.Maria, A.H., Denny, F.B., DiPietro, J.A., Howard, K.F., King, M.D.Geochemistry and Sr-Nd isotopic compositions of Permian ultramafic lamprophyres in the Reelfoot Rift- Rough Creek granen, southern Illinois and northwestern Kentucky.Lithos, Vol. 340-341, pp. 191-208.United States, Illinois, Kentuckycarbonatite

Abstract: Permian dikes, sills, and diatremes in southern Illinois and northwestern Kentucky (the Omaha, Wildcat Hills, Cottage Grove, Will Scarlet, Williams, Grant, and Clay Lick intrusions) share similar geochemistry and are classified as ultramafic lamprophyres. Major element compositions are 30-35 wt% SiO2, 6-7% Al2O3, 12-14% FeOt, 16-19% MgO, 3-5% TiO2, 11-16% CaO, 0.1-0.7% Na2O, 1.2-2.7% K2O, and 0.4-1.3% P2O5. The Grant Intrusive Breccia is an exception, with lower SiO2, Al2O3, FeOt, MgO, TiO2, and higher CaO. Typically, these rocks are fine grained, with phlogopite, serpentinized olivine ( Fo88), diopside, perovskite, Fe-Ti-spinel, apatite, and calcite. Blocky and lath-shaped pseudomorphs in some samples probably represent melilite, which would make the rocks alnöites. The Grant and Williams diatremes contain sedimentary and igneous clasts (including amphibole megacrysts) within a carbonate-rich matrix. The Grant exhibits pelletal lapilli and is characterized as a lamprophyre-carbonatite tuffisite. Trace element patterns exhibit enrichment of LREE, strong REE fractionation, and relative depletions of K, Sr, Zr, and Hf, closely matching those of the mela-aillikites of Aillik Bay, Labrador. The Grant Intrusive exhibits even greater REE enrichment and notable peaks at Nb, La, and Ce. Geochemical characteristics, including distributions of 143Nd/144Nd and 87Sr/86Sr, are consistent with near-primary melts from a metasomatized peridotite source containing phlogopite-rich veins. Derivation of the lamprophyres from carbonate-rich parental melts similar to the Grant Intrusive could be achieved by separation of carbonatite. A narrow range of initial 87Sr/86Sr (0.70301-0.70449), and initial eNd (3.7-5.1), suggests a uniform mantle source close to Bulk Earth. T-depleted mantle model ages range from 540 to 625 Ma, and might correlate with timing of enrichment of a lithospheric mantle source during the breakup of Rodinia.
DS1991-1054
1991
Mariani, E.Mariani, E., Venturelli, G., Toscani, L., Barbieri, M.The Jumilla lamproites, southeast Spain: late magmatic -hydrothermal activityEuropean Current Research Fluid Inclusions, Firenze, Italy April 10-12, Abstracts, ECROFI XI, p. 191-192GlobalLamproite, Jumilla
DS201412-0198
2014
Mariani, E.Dobson, D.P., Mariani, E.The kinetics of the reaction of majorite plus ferropericlase to ringwoodite: implications for mantle upwellings crossing the 660 km discontinuity.Earth and Planetary Science Letters, Vol. 408, pp. 110-118.MantleRingwoodite
DS1988-0730
1988
Mariani, E.S.Venturelli, G., Mariani, E.S., Foley, S.F., Capedri, S., CrawfordPetrogeneis and conditions of crystallization of SpanishlamproiticrocksCanadian Mineralogist, Vol. 26, No. 1, March pp. 67-80GlobalLamproite
DS1999-0808
1999
Mariano, A.Wright, W.R., Mariano, A., Hagni, R.D.Pyrochlore mineralization and glimmerite formation in the Elder ( Lake LeMoyne) carbonatite complex.The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) 33rd Forum Industrial Minerals Proceedings, Vol. 50, pp. 205-13.Quebec, Ungava, LabradorCarbonatite - mineralogy
DS201702-0249
2016
Mariano, A. Jr.Verplanck, P.L., Mariano, A.N., Mariano, A. Jr.Rare earth element ore geology of carbonatites.Reviews in Economic Geology, Vol. 18, pp. 5-32.GlobalCarbonatite
DS201212-0443
2012
Mariano, A.Jr.Mariano, A.N., Mariano, A.Jr.Rare earth mining and exploration in North America.Elements, Vol. 8, 5, Oct. pp. 369-376.Canada, United StatesEconomics - overview of mode of occurrence, mineralogy, history of exploration
DS201412-0550
2014
Mariano, A.Jr.Mariano, A.N., Mariano, A.Jr.Cathodluminescence as a tool in exploration geology.GAC/MAC short Course, MayTechnologyCathodluminescence
DS201605-0916
2016
Mariano, A.M.Jr.Verplanck, P.L., Mariano, A.N., Mariano, A.M.Jr.Rare earth element ore geology of carbonatites.SEG Reviews in Economic Geology, editors Verplanck, P.L., Hitzman, M.W., No. 18, pp. 5-32.China, United States, CaliforniaBauan Obo, Maoniuping, Dalucao, Mountain Pass
DS1975-0801
1978
Mariano, A.N.Mariano, A.N.The Application of Catholuminescence for Carbonatite Exploration and Characterization.I Symposio International De Carbonatitos, Pocos De Caldas, Brasil, PP. 39-57.GlobalExperimental Studies, Rare Earth Elements (ree), Probe Data
DS1983-0273
1983
Mariano, A.N.Haggerty, S.E., Mariano, A.N.Strontian Loparite and Strontio Chevkinite: Two New Minerals in Rheomorphic Fenites from the Parana Basin Carbonatites, south America.Contributions to Mineralogy and Petrology, Vol. 84, No. 4, PP. 365-381.Brazil, ParaguayRelated Rocks, Mineralogy
DS1985-0413
1985
Mariano, A.N.Mariano, A.N., Druecker, M.D.Alkaline Igneous Rocks and Carbonatites of ParaguayGeological Society of America (GSA), Vol. 17, No. 3, P. 166. (abstract.).South America, ParaguayGeophysics, Lineaments
DS1986-0204
1986
Mariano, A.N.Eby, G.N., Mariano, A.N.Geology and geochronology of carbonatites peripheral to the Parana Brasil-ParaguayGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 66, (abstract.)Brazil, Paraguay, South AmericaCarbonatite
DS1986-0525
1986
Mariano, A.N.Mariano, A.N.Nature of economic mineralization in carbonatitesGeological Association of Canada (GAC) Annual Meeting, Vol. 11, p. 99. (abstract.)GlobalCarbonatite, Lanthanides, Rare earth
DS1989-0937
1989
Mariano, A.N.Mariano, A.N.Nature of economic mineralization in carbonatites and related rocksCarbonatites -Genesis and Evolution, Ed. K. Bell Unwin Hyman Publ, pp. 149-California, China, Tanzania, Burundi, Brazil, VenezuelaKenya, Australia, Rare earths, Economics
DS1989-0938
1989
Mariano, A.N.Mariano, A.N.Classification of rare earth elements (REE) in carbonatitesReviews in Mineralogy: Geochemistry and mineralogy of Rare earth, Vol. 21, pp. 330-334California, Malawi, Tanzania, Brazil, Burundi, China, AustraliaCarbonatite, rare earth elements (REE).
DS1989-0939
1989
Mariano, A.N.Mariano, A.N., Francis, C.A.Dalyite from fenites in carbonatite complexes of the Minas Gerais-Goiasbelt, BrasilGeological Society of America (GSA) Annual Meeting Abstracts, Vol. 21, No. 6, p. A46. AbstractBrazilCarbonatite, Mineralogy -Dalyite
DS1989-0940
1989
Mariano, A.N.Mariano, A.N., Roeder, P.L.Wohlerite: chemical composition, cathodoluminescence and environment ofcrystallizationCanadian Mineralogist, Vol. 27, No. 4, December pp. 709-720OntarioPrairie Lake, Alkaline Complex
DS1990-0986
1990
Mariano, A.N.Mariano, A.N., Mitchell, R.H.Mineralogy and geochemistry of perovskite- rich pyroxenitesGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Vancouver 90 Program with Abstracts, Held May 16-18, Vol. 15, p. A83. AbstractBrazil, North America, Greenland, RussiaCarbonatite, Alkaline rocks
DS1991-0751
1991
Mariano, A.N.Hughes, J.M., Cameron, M., Mariano, A.N.Rare earth element ordering and structural variations in natural rare earth bearing apatitesAmerican Mineralogist, Vol. 76, pp. 1165-1173Quebec, New MexicoOka, Carbonatite
DS1991-1055
1991
Mariano, A.N.Mariano, A.N., Marchetto, M.Serra Negra and Salitre-carbonatite alkaline igneous complexFifth International Kimberlite Conferences Field Excursion Guidebook, Servico Geologico do Brasil (CPRM) Special, pp. 75-82BrazilCarbonatite, Alkaline rocks
DS1991-1056
1991
Mariano, A.N.Mariano, A.N., Mitchell, R.H.Mineralogy and geochemistry of perovskite rich pyroxenitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 251-253BrazilCatalao I, Serra Negra, Tapira, glimmerite, Anatase, Rhabdophane
DS1992-0408
1992
Mariano, A.N.Eby, G.N., Mariano, A.N.Geology and geochronology of carbonatites and associated alkaline rocks peripheral to the Parana Basin, Brasil-ParaguayJournal of South American Earth Sciences, Vol. 6, No. 3, October pp. 207-216Brazil, ParaguayCarbonatite, Geochronology
DS1996-1497
1996
Mariano, A.N.Wall, F., Mariano, A.N.Rare earth minerals in carbonatites: a discussion centred on the Kangankunde carbonatite, Malawi.Mineralogical Soc. Series, No. 7, pp. 193-226.MalawiRare earth minerals, Carbonatite, Deposit - Kangankunde
DS1997-0701
1997
Mariano, A.N.Lumpkin, G.R., Leung, S.H.F., Mariano, A.N.Paragenesis and composition of columbite and pyrochlore from the Blue Rivercarbonatite, British Columbia.Geological Association of Canada (GAC) Abstracts, British ColumbiaCarbonatite
DS1997-0702
1997
Mariano, A.N.Lumpkin, G.R., Mariano, A.N., Leung, S.H.F.Ideal defect pyrochlores from the Arax carbonatite complex and laterite Alto Paranaba Province, Brasil.Geological Association of Canada (GAC) Abstracts, POSTER.BrazilCarbonatite, Deposit - Arax
DS1997-0803
1997
Mariano, A.N.Mitchell, R.H., Xiong, J., Mariano, A.N., Fleet, M.E.Rare earth element activated cathodluminescence in apatiteCanadian Mineralogist, Vol. 35, No. 4 Aug. p. 979-998.GlobalCarbonatite, Alkaline rocks
DS1997-1270
1997
Mariano, A.N.Wright, W.R., Mariano, A.N.Petrology and geochemistry of the ultrapotassic rocks from the Sabatini volcanic district, alkaline magma....Geological Society of America (GSA) Abstracts, Vol. 29, No. 4, Apr. p. 79.QuebecCarbonatite
DS1997-1271
1997
Mariano, A.N.Wright, W.R., Mariano, A.N., Hagni, R.D.Geological, petrological, mineralogical ( including rare earth elements (REE) and Nb-Tamineralization) and geochemical examinationGeological Association of Canada (GAC) Abstracts, POSTER.Quebec, Labrador TroughCarbonatite, Deposit - Eldor
DS2001-1215
2001
Mariano, A.N.Wall, F., Zaitsev, A.N., Mariano, A.N.Rare earth pegmatites in carbonatitesJournal of South African Earth Sciences, Vol. 32, No. 1, p. A 35-6.(abs)GlobalCarbonatite, Pegmatites - rare earth elements (REE).
DS2002-0630
2002
Mariano, A.N.Hagni, R.D., Shivdansan, P.A., Mariano, A.N.Cathodluminescence microscopy applications to carbonatite ores: carbonatites and fluorite ores and concentrates at Okorusu, Namibia.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.151,246.NamibiaCarbonatite
DS2002-1473
2002
Mariano, A.N.Shivdasan, P.A., Hagni, R.D., Mariano, A.N.Character, paragenetic sequence and origin of the carbonatite host rocks for the fluorite deposits at Okorusu, Namibia.11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 40.NamibiaCarbonatite - mineralogy
DS2002-1474
2002
Mariano, A.N.Shivdasan, P.A., Mariano, A.N., Mitchell, R.H.Celsian and slawsonite in the Okorusu complex, Namibia11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 40.NamibiaCarbonatite - mineralogy
DS200712-0680
2006
Mariano, A.N.Mariano, A.N., Schatzlein, D.Rapid in field identification of rare earth elements (REE) using field portable XRF.The Gangue, GAC, MDD, CIM newsletter, No.89, April, pp. 1, 8-11.Canada, Northwest TerritoriesThor Lake area, technology REE
DS201212-0443
2012
Mariano, A.N.Mariano, A.N., Mariano, A.Jr.Rare earth mining and exploration in North America.Elements, Vol. 8, 5, Oct. pp. 369-376.Canada, United StatesEconomics - overview of mode of occurrence, mineralogy, history of exploration
DS201412-0550
2014
Mariano, A.N.Mariano, A.N., Mariano, A.Jr.Cathodluminescence as a tool in exploration geology.GAC/MAC short Course, MayTechnologyCathodluminescence
DS201502-0081
2015
Mariano, A.N.Moore, M., Chakhmouradian, A.R., Mariano, A.N., Sidhu, R.Evolution of rare-earth mineralzation in the Bear Lodge carbonatite, Wyoming: mineralogical and isotopic evidence.Ore Geology Reviews, Vol. 64, pp. 499-521.United States, Wyoming, Colorado PlateauDeposit - Bear Lodge
DS201512-1982
2015
Mariano, A.N.Verplanck, P.L., Farmer, G.L., Mariano, A.N.Nd and Sr isotopic composition of rare earth element mineralized carbonatites.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 65-74.GlobalCarbonatite

Abstract: For nearly 50 years, carbonatites have been the primary sources of niobium and rare earth elements (REEs), particularly the light REEs including La, Ce, Pr, and Nd. In addition, carbonatites may be enriched in other critical elements and have the potential to be future sources. Currently, only fi ve of the more than 500 known carbonatites in the world are being mined for REEs: Bayan Obo (Inner Mongolia, China); Maoniuping (Sichuan, China); Dalucao (or Daluxiang, Sichuan, China); and Mountain Pass (California, USA), and the carbonatite-derived laterite at Mount Weld (Australia). To achieve ore-grade REE enrichment, initial carbonatitic magmas require an adequate endowment of REEs and need to evolve in ways for these elements to concentrate in REE-bearing mineral phases. Radiogenic isotope studies of carbonatites clearly point to a mantle origin, but a wide range in isotopic compositions has led to contrasting views about the specifi c mantle reservoir(s) that sourced carbonatites. In this study we use the neodymium and strontium isotopic compositions of a suite of mineralized carbonatites to establish the nature of the source magmas. We examine samples that span a wide range in age (~23 Ma to 1385 Ma), Nd concentrations (3720 to 32,900 ppm), and Sr concentrations (2290 to 167,900 ppm). Our Nd and Sr isotopic data include multiple samples from Mountain Pass (USA; eNd i = -3.1 to -5.4, Sri = 0.70512 to 0.70594), Elk Creek (USA; ~eNd i = 1.7, Sri = 0.7035), and Maoniuping (China; eNd i = -4.1 and -4.2, Sri = 0.70627 and 0.70645), and one sample each from Bear Lodge (USA; eNd i = 0.1, Sri = 0.70441), Kangankunde (Malawi; eNd i = 3.3, Sri = 0.70310), Adiounedj (Mali; eNd i = -0.1, Sri = 0.70558), and Mushgai Khudag (Mongolia; eNd i = -1.3, Sri = 0.70636). Isotopic data from two producing carbonatite REE deposits (Mountain Pass and Maoniuping) have broadly similar isotopic compositions (eNd i = -3.1 to -5.4 and Sri = 0.7051 to 0.7065), and these compositions point to a carbonated source in the lithospheric mantle. Mineralized but unmined carbonatites have higher Nd initial isotopic compositions (eNd i = -1.3 to 3.3) and a wider range in Sr isotopic compositions (Sri = 0.70310 to 0.70637), but these data are consistent with a lithospheric mantle reservoir.
DS201605-0916
2016
Mariano, A.N.Verplanck, P.L., Mariano, A.N., Mariano, A.M.Jr.Rare earth element ore geology of carbonatites.SEG Reviews in Economic Geology, editors Verplanck, P.L., Hitzman, M.W., No. 18, pp. 5-32.China, United States, CaliforniaBauan Obo, Maoniuping, Dalucao, Mountain Pass
DS201702-0249
2016
Mariano, A.N.Verplanck, P.L., Mariano, A.N., Mariano, A. Jr.Rare earth element ore geology of carbonatites.Reviews in Economic Geology, Vol. 18, pp. 5-32.GlobalCarbonatite
DS1999-0505
1999
Mariano, G.Neves, S.P., Mariano, G.Assessing the tectonic significance of a large scale transcurrent shearzone system: Pernambuco lineamentJournal of Structural Geology, Vol. 21, No. 10, Oct. 1, pp. 1369-84.BrazilTectonics - lineament
DS2000-0706
2000
Mariano, G.Neves, S.P., Mariano, G., Guimares, da Silva Filho, MeloIntralithospheric differentiation and crustal growth: evidence from Bororema province, northeastern BrasilGeology, Vol. 28, No. 6, June pp. 519-22.BrazilAlkaline rocks, Geochemistry, Proterozoic crustal growth
DS200412-1422
2004
Mariano, G.Neves, S.P., Mariano, G.Heat producing elements enriched continental mantle lithosphere and Proterozoic intracontinental orogens: insights from BrasiliaGondwana Research, Vol. 7, 2, pp. 427-436.South America, Brazil, Africa, west AfricaGeothermometry, tectonics
DS200412-1423
2004
Mariano, G.Neves, S.P., Melo, S.C., Moura, C.A.V., Mariano, G., Ragel Da Silva, J.M.Zircon Pb Pb geochronology of the Aruaru area, northeastern Brazil: temporal constraints on the Proterozoic evolution of BorboreInternational Geology Review, Vol. 46, 1, pp. 52-63.South America, BrazilGeochronology
DS1986-0102
1986
Mariano, G. Castelo.Branco, R., Mariano, G. Castelo.Geologic aspects of Brazilian kimberlites.(in Portugese)Rem. Revista Escola de Minas, (in Portugese)., Vol. 39, No. 4, pp. 28-36BrazilBlank
DS1991-1057
1991
Mariano, J.Mariano, J., Hinze, W.J.A geophysical investigation of the midcontinent rift and the associated crustal structure in eastern Lake SuperiorGeological Society of America, Abstract Volume, Vol. 23, No. 3, March p. 26MidcontinentGeophysics, Tectonics -rift
DS1992-0711
1992
Mariano, J.Hinze, W.J., Allen, D.J., Mariano, J.Lithosphere of the Midcontinent Rift region: progress and problemsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 319MidcontinentMidcontinent Rift, Lithosphere
DS1992-0998
1992
Mariano, J.Mariano, J., Hinze, W.J.Magnetic modeling of complexly magnetized bodies with implications to the structure of the midcontinent rift in eastern Lake SuperiorEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 320OntarioMidcontinent Rift, Geophysics -magnetics
DS1994-1102
1994
Mariano, J.Mariano, J., Dumont, R., Ross, G., Teskey, D.Correlations between mantle derived alkaline intrusive rocks and semi-magnetic lineations in southeastern Alberta.Geological Survey of Canada Open Forum January 17-19th. Abstracts only, p. 26, 27.AlbertaGeophysics -magnetics, Alkaline rocks
DS1994-1103
1994
Mariano, J.Mariano, J., Hinze, W.J.Gravity and magnetic models of the Midcontinent Rift in eastern LakeSuperior.Canadian Journal of Earth Sciences, Vol. 31, No. 4, April pp. 661-674.Ontario, MichiganGeophysics -gravity, magnetics, Tectonics -Midcontinent rift
DS1994-1104
1994
Mariano, J.Mariano, J., Hinze, W.J.Structural interpretation of Midcontinent Rift in east Lake Superior from seismic reflection, potential fieldCanadian Journal of Earth Sciences, Vol. 31, No. 4, April pp. 619-628Ontario, MichiganGeophysics -seismics, Tectonics -Midcontinent rift
DS1994-1105
1994
Mariano, J.Mariano, J., Hinze, W.J.Structural interpret. Midcontinent Rift in eastern Lake Superior from seismic reflection and potential field.Canadian Journal of Earth Sciences, Vol. 31, No. 4, April pp. 619-628.Ontario, MichiganGeophysics -seismics, Tectonics -Midcontinent rift
DS1995-0023
1995
Mariano, J.Allen, D.J., Braile, L.W., Hinze, W.J., Mariano, J.The midcontinent rift system United States (US): a major Proterozoic continental riftContinental Rifts: evolution, structure, tectonics, No. 25, pp. 375-408Michigan, Wisconsin, Kansas, Lake Superior regionGeophysics - seismics, gravity, Structure
DS1995-0024
1995
Mariano, J.Allen, D.J., Braile, L.W., Hinze, W.J., Mariano, J.The midcontinent rift system United States (US): a major Proterozoic continental riftContinental Rifts: evolution, structure, tectonics, No. 25, pp. 375-408.Michigan, Wisconsin, Kansas, Lake Superior regionGeophysics - seismics, gravity, Structure
DS1995-0803
1995
Mariano, J.Hinze, W.J., Allen, D.J., Braile, L.W., Mariano, J.The Midcontinent rift system: an overviewBasement Tectonics 10, held Minnesota Aug 92, pp. 3-6.MidcontinentTectonics
DS1995-1169
1995
Mariano, J.Mariano, J., Hinze, W.J.Integrated potential field and seismic reflection studies of Midcontinent rift in eastern Lake Superior.Basement Tectonics 10, held Minnesota Aug 92, pp. 11-14.MidcontinentTectonics, Geophysics -seismics
DS1997-0977
1997
Mariano, J.Ross, G.M., Mariano, J., Dumont, R., Kjarsgaard, B., TeskeyWas Eocene magmatism Wide spread in subsurface southern Alberta? evidence from new aeromagnetic anomaly dataGeological Survey of Canada, Bulletin. No. 500, pp. 235-246.AlbertaMagmatism, Archean Medicine Hat Block
DS1997-0941
1997
Mariappan, N.Radhakrishnan, V., Mariappan, N., Thrivikramji, L.P.A QUICKBASE program to analyse pebble shapesComputers and Geosciences, Vol. 23, No. 3, pp. 325-327.GlobalZingg shape classification, Alluvials, placers, pebbles
DS1982-0396
1982
Marie, A.M.Marie, A.M., Mainprice, D.H., Sobolev, N.V.A Transmission Electron Microscopy Study of Olivine Inclusions in Diamond.Proceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 200, (abstract.).RussiaKimberlite, Udachnaya
DS1859-0009
1742
Marie ElizabethMarie ElizabethCatalogue des DiamantsBruxelles: George Fricx, 24P.GlobalDiamond Occurrence
DS201807-1512
2018
Marien, C.Marien, C., Dukstra, A.H., Wilkins, C.The hydrothermal alteration of carbonatite in the Fen complex, Norway: mineralogy, geochemistry and implications for rare earth element resource formation.Mineralogical Magazine Open access special publication Critical metal mineralogy and ore genesis, Vol. 82 (S1) pp. S115-S131.Europe, Norwaycarbonatite

Abstract: The Fen Complex in Norway consists of a ~583 Ma composite carbonatite-ijolite-pyroxenite diatreme intrusion. Locally, high grades (up to 1.6 wt.% total REE) of rare-earth elements (REE) are found in a hydrothermally altered, hematite-rich carbonatite known as rødbergite. The progressive transformation of primary igneous carbonatite to rødbergite was studied here using scanning electron microscopy and inductively coupled plasma-mass spectrometry trace-element analysis of 23 bulk samples taken along a key geological transect. A primary mineral assemblage of calcite, dolomite, apatite, pyrite, magnetite and columbite with accessory quartz, baryte, pyrochlore, fluorite and REE fluorocarbonates was found to have transformed progressively into a secondary assemblage of dolomite, Fe-dolomite, baryte, Ba-bearing phlogopite, hematite with accessory apatite, calcite, monazite-(Ce) and quartz. Textural evidence is presented for REE fluorocarbonates and apatite breaking down in igneous carbonatite, and monazite-(Ce) precipitating in rødbergite. The importance of micro-veins, interpreted as feeder fractures, containing secondary monazite and allanite, is highlighted. Textural evidence for included relics of primary apatite-rich carbonatite are also presented. These acted as a trap for monazite-(Ce) precipitation, a mechanism predicted by physical-chemical experiments. The transformation of carbonatite to rødbergite is accompanied by a 10-fold increase in REE concentrations. The highest light REE (LREE) concentrations are found in transitional vein-rich rødbergite, whereas the highest heavy REE (HREE) and Th concentrations are found within the rødbergites, suggesting partial decoupling of LREE and HREE due to the lower stability of HREE complexes in the aqueous hydrothermal fluid. The hydrothermal fluid involved in the formation of rødbergite was oxidizing and had probably interacted with country-rock gneisses. An ore deposit model for the REE-rich rødbergites is presented here which will better inform exploration strategies in the complex, and has implications for carbonatite-hosted REE resources around the world.
DS1989-0941
1989
Marillier, F.Marillier, F., Keen, C.E., Stockmal, G.S.Seismic reflection probes the deep structure of theCanadianAppalachiansGeos, Vol. 18, No. 1, Winter pp. 16-20AppalachiaTectonics, Structure
DS1989-0942
1989
Marillier, F.Marillier, F., Keen, C.E., Stockmal, G.S., Quinlan, G., WilliamsCrustal structure and surface zonation of the CanadianAppalachians:implications of deep seismic reflection dataCanadian Journal of Earth Sciences, Vol. 26, No. 2, February pp. 305-321NewfoundlandStructure, Geophysics
DS1990-1419
1990
Marillier, F.Stockmal, G.S., Colman-Sadd, Keen, C.E., Marillier, F., O'BrienDeep seismic structure and plate tectonic evolution of the CanadianAppalachiansTectonics, Vol. 9, No. 1, February pp. 45-62AppalachiaTectonics, Geophysics-seismics
DS1992-0761
1992
Marillier, F.Jackson, H.R., Dickie, K., Marillier, F.A seismic reflection study of northern Baffin Bay: implication for tectonicevolutionCanadian Journal of Earth Sciences, Vol. 29, No. 11, November, pp. 2353-2369GlobalGeophysics -seismics, Tectonics
DS202012-2228
2020
Marimon, R.S.Marimon, R.S., Trouw, R.A.J., Dantas, E.L.Significance of age periodicity in the continental crust record: the Sao Francisco craton and adjacent Neoporterozoic orogens as a case study.Gondwana Research, Vol. 86, pp. 144-163. pdfSouth America, Brazilmagmatism

Abstract: The São Francisco Craton, in Brazil, together with adjacent orogenic systems formed during Gondwana assemblage, are well-suited for the study of crustal growth processes. The region's geological history is marked by a series of complete tectono-metamorphic cycles, from the Archean to late Neoproterozoic, comprising arc-related magmatism followed by continental collisions and ultimately post-tectonic igneous events and rifting. In this contribution, a comprehensive isotopic database was compiled from the literature, composed mainly of high-quality U-Pb magmatic and metamorphic ages (ca. 1000), together with Lu-Hf (ca. 1300) and Sm-Nd (ca. 300) data. Using this database, combined with a tectonic/geochemical synthesized review of the region, it is possible to test which of the available contending models can better explain the apparent periodicity in the formation of the continental crustal. Some interpreted the peaks and troughs in the crustal age record as periods of increased magmatic production, controlled by periodic mantellic events. Another hypothesis is that subduction-related rocks are shielded from tectonic erosion after continental amalgamation, the peaks thus reflecting enhanced preservation potential. The latter hypothesis is favored, as the variability regarding the timing of arc-related peak magmatic production (U-Pb age peaks) from different tectonic provinces around the globe and in the considered regions, coupled to the fact that peak arc-production is always closely followed in time by major continental amalgamations (supercontinent formation), precludes a unified global causation effect, such as mantellic overturns or slab avalanches, and supports the preservation bias hypothesis. Furthermore, the worldwide (including the São Francisco Craton) occurrence of plume-related magmatism is concentrated during the periods of supercontinent break-up (i.e. after major collisions), which better relates to a top-down control on mantle convection and opposes most of the models that advocate for the primary periodicity of magmatic production, which predict enhanced plume activity slightly prior or concomitant to supercontinent formation events.
DS201212-0522
2012
Marin, Y.BNikitina, L.P., Marin, Y.B, Skublov, S.G., Korolev, N.M., Saltykova, A.K., et al.U Pb age and geochemistry of zircon from mantle xenoliths of the Katoka and Kat- 115 kimberlitic pipes ( Republic of Angola).Doklady Earth Sciences, Vol. 445, 1, pp. 840-844.Africa, AngolaDeposit - Katoka (Catoca) Kat-115
DS201412-0474
2014
Marin, Y.B.Korolev, N.M., Marin, Y.B., Nikitina, L.P., Zinchenko, V.N., Chissupa, H.M.High Nb rutile from upper mantle eclogite xenoliths of the diamond bearing kimberlite pipe, Catoca ( Angola).Doklady Earth Sciences, Vol. 454, 1, pp. 50-53.Africa, AngolaDeposit - Catoca
DS201112-0971
2011
Marin, Yu.B.Skublov, S.G., Astafev, B.Yu., Marin, Yu.B., Berezin, A.V., Melnik, A.E., Presnyakov, S.L.New dat a on the age of eclogites from the Belmorian mobile belt at Gridino settlement area.Doklady Earth Sciences, Vol. 439, 2, pp.1163-1170.RussiaEclogite
DS201212-0666
2012
Marin, Yu.B.Skublov, S.G., Nikitina, L.P., Marin, Yu.B., Levskii, L.K., Guseva, N.S.U Pb age and geochemistry of zircons from xenoliths of the V. Grib kimberlitic pipe, Arkhangelsk diamond province.Doklady Earth Sciences, Vol. 444, 1, pp. 595-600.Russia, Archangel, Kola PeninsulaDeposit - Grib
DS201412-0838
2013
Marin, Yu.B.Skublov, S.G., Melnik, A.E., Marin, Yu.B., Berezin, A.V., Bogomolov, E.S., Ishmurzin, F.I.New dat a on the age ( U-Pb, Sm-Nd) of metamorphism and a protolith of eclogite like rocks from the Krasnaya Guba area, Belomorian belt.Doklady Earth Sciences, Vol. 451, 1, pp. 1156-1164.RussiaEclogite
DS201806-1210
2018
Marin, Yu.B.Babushkina, M.S., Ugolkov, V.L., Marin, Yu.B., Nikitina, L.P., Goncharov, A.G.Hydrogen and carbon groups in the structures of rock forming minerals of rocks of the lithospheric mantle: FTIR and STA + QMS data. Lherzolites, peridotitesDoklady Earth Sciences, Vol. 479, 2, pp. 456-459.Russia, Siberiadeposit - Udachnaya

Abstract: Using IR-Fourier spectrometry (FTIR) and simultaneous thermal analysis combined with quadrupole mass spectrometry of thermal decomposition products (STA + QMS), olivines and clinopyroxene from xenolites of spinel and garnet lherzolites contained in kimberlites and alkaline basalts were studied to confirm the occurrence of hydrogen and carbon within the structure of the minerals, as well as to specify the forms of H and C. The presence of hydroxyl ions (OH-) and molecules of crystal hydrate water (H2Ocryst) along with CO2, CH, CH2, and CH3 groups was detected, which remained within the structures of mantle minerals up to 1300°C (by the data of both techniques). The total water (OH-and H2Ocryst) was the prevailing component of the C-O-H system.
DS1975-0332
1976
Mar'in, A.M.Mar'in, A.M.A Find of Melilite-bearing Ultramafic Rocks of the Rudny Altai.Akad. Nauk Ssr Izv, Ser. Geol., Vol. 33, No. 3, PP. 44-47.RussiaBlank
DS2001-0891
2001
MarinceaPascal, M.L., Fonteilles, Verkaeren, Piret, MarinceaThe melilite bearing high temperature skarns of the Apuseni Mountains, Carpathians, Romania.Canadian Mineralogist, Vol. 39, No. 5, Oct. pp. 1405-34.RomaniaMelilite
DS201803-0463
2017
Maringira, G.Maringira, G., Nyamunda, T.Duty versus agency in the security state of Zimbabwe: soldiers deployment in Chiadzwa diamond mining.The Extractive Industries and Society, Vol. 4, pp. 172-179.Africa, Zimbabweartisanal mining

Abstract: The deployment of soldiers’ in diamond mining areas in Zimbabwe is beginning to receive much scholarly attention, partly because scholars researching on such issues are mainly driven by the meta-narratives of ‘artisanal miners’, popularly known as "magweja" in the Zimbabwean context. In many cases soldiers are presented as perpetrators of violence within deployed areas, with magweja and villagers, as victims of military deployment. While this is not untrue, this article explores the ways in which soldiers developed mutual relationships with magweja, friendships and interactions with villagers, including sexual relationships in the communities surrounding the diamond area. However, we assert that these relationships were always implicitly characterised by unequal power dynamics in which the authority of deployed soldiers was ominously present and fear sometimes informed the actions of villagers. Soldiers’ power was always materially represented by the authority vested in them by a powerful demagogic state. It was visibly represented through their combat uniforms, and the gun as part of their daily standing orders, including other soldiering routines such as patrols, and guard duties. We argue that even beyond these circumscribed conditions of relations building, the people behind the combat uniforms had their own agencies that never always resonated with that of the state. Their actions were informed by the chain of command and the consequences wrought by failing to abide by standing orders. In this article, we illuminate those hidden narratives and expose the manner in which the dictatorial state instrumentalises its armed forces despite the disparate personal agencies of those soldiers which are suppressed by the very nature of military service. The paper is based on interviews with soldiers, "magweja" and villagers.
DS1994-1808
1994
Maringolo, V.Ulbrich, M.N.C., Maringolo, V., Vlach, S.R.F.Xenocrysts in mafic dikes from the Fernando de Noronha ArchipelagoInternational Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 36-38.BrazilAlkaline rocks
DS1986-0531
1986
Marinho, M.Mascle, J., Marinho, M., Wannesson, J.The structure of the Guinean continental margin: Implications for the connection between the central and south AtlanticoceansGeologische Rundschau, Vol. 75, No. 1, pp. 57-70GuineaTectonics
DS1988-0443
1988
Marinho, M.Mascle, J., Blarez, E., Marinho, M.The shallow structures of the Guinea and Ivory Coast-Ghana transformmargins: their bearing on the equatorial Atlantic Mesozoic evolutionTectonophysics, Vol. 155, No. 1-4, Dec. 1, pp. 193-210GhanaStructure
DS200812-0206
2008
Marini, J.C.Chauvel, C., Lewin, E., Carpenier, M., Arndt, N.T., Marini, J.C.Role of recycled oceanic basalt and sediment in generating the Hf Nd mantle array.Nature Geoscience, Vol. 1, 1, pp. 64-67.MantleGeochemistry
DS200712-0170
2007
Marini, J-C.Chavel, C., Lewin, E., Carpentier, M., Marini, J-C.Recycled oceanic crust and sediments control the Hf-Nd mantle array.Plates, Plumes, and Paradigms, 1p. abstract p. A163.MantleKimberlite
DS200512-0687
2004
Marinkovic, S.N.Marinkovic, S.N.Diamond synthesized at low pressure.Chemistry and Physics of Carbon, Vol. 29, pp. 71-208. Ingenta 1045668832Experimental petrology
DS1986-0122
1986
Marion, C.Campiglio, C., Marion, C., Vanier, M.Study of an olivine boninite from New Caledonia- petrography and mineralchemistry.(in French)Bulletin. Mineralogie, (in French), Vol. 109, No. 4, pp. 423-440New CaledoniaBlank
DS1991-1916
1991
Marion, P.Yvon, J., Marion, P., Michot, L., Villieras, F., Wagner, F.E.Development of mineralogy applications in mineral processingEur. Journal of Mineral, Vol. 3, No. 4, pp. 667-676GlobalMineral processing, overview
DS2002-1025
2002
Marion, S.McCammon, C.A., Beccero, A.I., Lauterbach, S., Blass, U., Marion, S.Oxygen vacancies in perovskite and related structures: implications for the lower mantle.Materials Research Society Symposium Proceedings, Vol. 718, pp. 109-114. Ingenta 1025440383MantlePerovskite
DS1981-0283
1981
Mariotti, P.A.Mariotti, P.A.Vein Controlled Surf Induced Spheroidal Weathering in Harzburgite Presque Isle Marquette Michigan.Geological Society of America (GSA), Vol. 13, No. 6, MARCH P. 288. (abstract.).United States, Michigan, Great LakesBlank
DS201812-2856
2019
Mariotto, G.Nazzarini, S., Nestola, F., Zanon, V., Bindi, L., Scricciolo, E., Petrelli, M., Zanatta, M., Mariotto, G., Giuli, G.Discovery of moissanite in a peralkaline syenite from the Azores Islands.Lithos, Vol. 324-325, pp. 68-73.Europe, Portugal, Azoresmoissanite

Abstract: Our discovery of moissanite grains in a peralkaline syenite from the Água de Pau Volcano (São Miguel, Azores Islands, Portugal) represents the first report of this mineral in present day oceanic geodynamic settings. Raman spectroscopy and single-crystal X-ray diffraction show the presence of both the 6H and 4H polytypes with the predominance of the first one. The distribution of trace elements is homogeneous, except for Al and V. Azorean moissanite often hosts rounded inclusions of metallic Si and other not yet identified metallic alloys. A process involving a flushing of CH4-H2 ultra-reducing fluids in the alkaline melts might be considered as a possible mechanism leading to the formation of natural SiC, thus calling for strongly reducing conditions that were locally met in the crust-mantle beneath the São Miguel Island.
DS200512-0806
2002
Mariynov, Yu.A.Okamura, S., Mariynov, Yu.A.Cenozoic volcanism of Far East Russia: the relative importance of subcontinental lithosphere and asthenospheric mantle.Deep Seated Magmatism, magmatism sources and the problem of plumes., pp. 95-101.RussiaMagmatism
DS202106-0940
2021
Marjo, C.Halim, A.Y., Kelloway, S.J., Marjo, C., Regenauer-Lieb. K.A Hylogger-Itrax core-scanner comparison for multi-scale high resolution petrophysical characterization workflow. * not specific to diamondsApplied Chemistry, in press available, 18p. PdfGlobalHylogger

Abstract: Recent advances in core scanning technologies allow for fast and non-destructive chemical and mineral profiling of rock samples for mineral services and oil and gas exploration. The aim of these automatic core scan methods is to obtain valuable information for profiling drill core cuttings with minimum sample preparation at relatively high speed. In the last decade, a core logging system using an automated infrared-based hyperspectral line-profiling system, Hylogger, has progressed to become an effective standard for the Australian mineral exploration industry. Its results are used to rapidly obtain mineralogical information allowing the characterisation of different geological formations in near real-time. The interpretation of Hylogger data can be challenging for certain complex mineral mixtures. Here we solve this issue by augmenting the Hylogger interpretation with elemental analysis using the Itrax core scanner equipped with an X-ray fluorescence (XRF) spectrometer. The Itrax core scanner produces high-resolution elemental data of major, minor and trace elements in one dimension. We analyse and compare the Hylogger and Itrax data, with each dataset independently cross-checked using X-ray diffraction (XRD) and thin-section petrology and propose a workflow harvesting the mutual strengths of each method. The recommended workflow consists of rapid screening using Hylogger and XRF analysis, providing new insights into the mineralogy based on comparative multiscale element-mineral analysis. The workflow is tested on four different types of volcanic rock samples, where infrared spectra of individual minerals overlap. We tested tuffaceous ash, basaltic, dolerite, and basaltic-andesitic rocks. Our study shows that embedding Itrax core scanner data into the workflow provides a solution to the challenges of interpreting Hylogger data in complex mineral samples. The proposed workflow provides a total system for multiscale, high-resolution petrophysical analyses and rock property modelling.
DS1997-0734
1997
Marjoribanks, R.W.Marjoribanks, R.W.Geological methods in mineral exploration and miningChapman and Hall, 120p. $ 140.00 CanGlobalBook - Table of contents, Geological methods, techniques, mapping
DS200712-0076
2007
Mark, G.Betts, P.G., Giles, D., SChaefer, B.F., Mark, G.1600 -1500 Ma hotspot track in eastern Australia: implications for Mesoproterozoic continental reconstruction.Terra Nova, Vol. 19, 6, pp. 496-501.AustraliaHotspots, plumes
DS1992-0999
1992
Mark, K.Mark, K.From geosynclinal to geosynclineEarth Sciences History, Vol. 11, No. 2, pp. 68-69GlobalGeosyncline, Theory
DS1995-1170
1995
Markarian, D.Markarian, D., Grant, J.A., Elliott, B.E.LogView - microsoft windows borehole log ProgramGeological Survey of Canada, Open File 3055 $ 100.00GlobalComputer, Program -LogView
DS1989-0943
1989
Marker, A.Marker, A., Oliveira, J.J. de.Climatic control of the rare earth element distribution in weathering covers above alkaline rocks. southeast BahiaState/BrasilXiii International Geochemical Exploration Symposium, Rio 89 Brazilian Geochemical, pp. 217-219. AbstractBrazilAlkaline rocks, Geochemistry
DS1990-0987
1990
Marker, A.Marker, A., De Oliveira, J.J.The formation of rare earth element scavenger minerals in weathering products derived from alkaline rocks of southeast-Bahia, BrasilChemical Geology ( Geochem. of the Earth's surface and of min. formation, 2nd., Vol. 84, No. 1-4, July 5, pp. 373-374. AbstractBrazilAlkaline rocks, rare earth elements (REE).
DS1991-1058
1991
Marker, A.Marker, A., Friedrich, G., Carvalho, A., Melfi, A.Control of the distribution of Manganese, Cobalt, Zinc, Zrirconium, Titanium and REEs during the evolution of lateritic covers above ultramafic complexesJournal of Geochemical Exploration, Special Publications Geochemical, Vol. 40, No. 1-3, pp. 361-384Brazil, PhilippinesCarbonatite, Geochemistry -laterites
DS1994-1106
1994
Marker, A.Marker, A., De Oliveira, J.J.Climatic and morphological control of rare earth element distribution inweathering mantles on alkaline rocks.Catena, Special issue Laterization Processes, Vol. 21, No. 2-3, pp. 179-194.BrazilAlkaline rocks, Rare earths, Weathering, Laterization
DS1994-1107
1994
Marker, A.Marker, A., de Oliviera, J.J., Schellmann, W.Lithodependence of partly transported weathering horizons above a migmatite diabase contact in Central Bahia State, BrasilCatena, Laterization and Supergene Ore, Vol. 21, No. 2-3, pp. 215-227BrazilDiabase dike, Laterization
DS200612-0869
2005
Marker, B.R.Marker, B.R., Petterson, M.G., McEvoy, F., Stephenson, M.H.Sustainable minerals operations in the Developing World.Geological Society of London Special Publication, SP 250, 256p. aaprox. 160.00GlobalBook - resources
DS1987-0248
1987
Marker, m A.Germann, A., Marker, m A., Friefrich, G.The alkaline complex of Jacupiranga, Sao Paulo/Brasil;petrology and genetic considerationsSymposium on Latin American Geosciences, Zentralblatt fuer geologie und, Vol. 1987, No. 7-8, pp. 807-818BrazilAlkaline rocks, Carbonatite
DS2002-1642
2002
Marker, M.Van Gool, J.A.M., Connelly, J.N., Marker, M., Mengel, F.C.The Nagssugtoqidian Orogen of West Greenland: tectonic evolution and regional correlations from a West Greenland perspective.Canadian Journal of Earth Science, Vol.39,5, May, pp.665-86.GreenlandTectonics - Orogen, ESCOOT
DS1995-1171
1995
Marker, M.E.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
DS1988-0361
1988
Markezich, M.A.Knapp, R.W., Markezich, M.A., Wojcik, K.M.Seismic reflection studies at Silver City dome, KansasGeological Society of America (GSA) Abstracts, Vol. 20, p. 104. abstract onlyKansasLamproite, Geophysics- seismics
DS1988-0439
1988
Markezich, M.A.Markezich, M.A.A geophysical study of the Hill's Pond lamproite,Woodson and Wilsoncounties, KansasMsc. Thesis, University Of Kansas, Lawrence, 87pKansasLamproite, Geophysics
DS201808-1785
2018
Markham, M.L.Rose, B.C. ,Huang, D., Zhang, Z-H., Stevenson, P., Tyryshkin, A.M., Sangtawesin, S., Srinivasan, S., Loudin, L., Markham, M.L., Edmonds, A.M., Twitchen, D.J., Lyon, S.A., de Leon, N.P.Observation of an environmentally insensitive solid-state spin defect in diamond.Science , Vol. 361, July 6, p. 60-63.Technologysynthetic

Abstract: Engineering coherent systems is a central goal of quantum science. Color centers in diamond are a promising approach, with the potential to combine the coherence of atoms with the scalability of a solid-state platform. We report a color center that shows insensitivity to environmental decoherence caused by phonons and electric field noise: the neutral charge state of silicon vacancy (SiV0). Through careful materials engineering, we achieved >80% conversion of implanted silicon to SiV0. SiV0 exhibits spin-lattice relaxation times approaching 1 minute and coherence times approaching 1 second. Its optical properties are very favorable, with ~90% of its emission into the zero-phonon line and near -transform-limited optical linewidths. These combined properties make SiV0 a promising defect for quantum network applications.
DS201112-1120
2011
MarklWorgard, L., Trumbell, Keiding, Veksler, Wiedenbeck, Wenzel, MarklF, Cl, and S contents of olivine hosted melt inclusions from picritic dike rocks, Etendeka, NW Namibia.Goldschmidt Conference 2011, abstract p.2177.Africa, NamibiaPicrite
DS1997-0735
1997
Markl, G.Markl, G., Bucher, K.Proterozoic eclogites from the Lofiten Island, northern NorwayLithos, Vol. 42, No. 1-2, Dec. 1, pp. 15-36.NorwayEclogites
DS1998-0611
1998
Markl, G.Henjes-Kunst, F., Markl, G.Charnockitic intrusive rocks and related lamprophyres in central DronningMaud Land, East Antarctica...Journal of African Earth Sciences, Vol. 27, 1A, p. 110. AbstractAntarcticaMagmqatisM., Pan-African Orogeny
DS2003-0876
2003
Markl, G.Markl, G., Abart, R., Vennemann, T., Sommer, H.Mid-crustal metasomatic reaction veins in a spinel peridotiteJournal of Petrology, Vol. 44, 6, pp. 1097-1120.MantleBlank
DS200412-1226
2003
Markl, G.Markl, G., Abart, R., Vennemann, T., Sommer, H.Mid-crustal metasomatic reaction veins in a spinel peridotite.Journal of Petrology, Vol. 44, 6, pp. 1097-1120.MantleMetasomatism
DS200512-0390
2004
Markl, G.Halama, R., Vennnemann, T., Siebel, W., Markl, G.The Gronnedal Ika carbonatite syenite complex, South Greenland: carbonatite formation by liquid immiscibility.Journal of Petrology, Vol. 46, 1-2, pp. 191-217.Europe, GreenlandCarbonatite
DS200712-0402
2007
Markl, G.Halama, R., Joron, J-L., Villemant, B., Markl, G., Treuil, M.Trace element constraints on mantle sources during mid-Proterozoic magmatism: evidence for a link between Gardar and Abitibi mafic rocks.Canadian Journal of Earth Sciences, Vol. 44, 4, pp. 459-478.Canada, Quebec, Europe, GreenlandMagmatism
DS200712-0681
2007
Markl, G.Marks, M.A.W., Rudnick, R.L., McCammon, C., Vennemann, T., Markl, G.Arrested kinetic Li isotope fractionation at the margin of the Ilimaussaq complex: evidence for open system processes during final cooling peralkaline igneous rocksChemical Geology, Vol. 246, 3-4, pp. 207-230.Europe, GreenlandGeochronology
DS200912-0473
2009
Markl, G.Marks, M.A.W., Neukirchen, F., Vennemann, T., Markl, G.Textural, chemical and isotopic effects of late magmatic carbonatitic fluids in the carbonatite syenite Tamazeght complex, High Atlas Mountains, Morocco.Mineralogy and Petrology, Vol. 97, pp. 23-42.Africa, MoroccoCarbonatite
DS201012-0398
2009
Markl, G.Kohler, J., Schonenberger, J., Upton, B., Markl, G.Halogen and trace element chemistry in the Gardar Province, South Greenland: subduction related mantle metasomatism and fluid exsolution from alkalic melts.Lithos, Vol. 113, pp. 731-747.Europe, GreenlandMetasomatism
DS201012-0886
2010
Markl, G.Zaitssev, A.N., Wenzel, T., Markl, G., Spratt, J., Petrov, S.V., Williams, C.T.Sadiman volcano, Crater Highlands, Tanzania: does it really contain melilitites and carbonatites or is it just a phonolite nephelinite volcano?International Mineralogical Association meeting August Budapest, abstract p. 559.Africa, TanzaniaPetrology
DS201112-0266
2011
Markl, G.Derrey, I., Hettmann, K., Thaler, F., Wenzel, T., Marks, M., Markl, G.Sulfur content and speciation in sodalite and its possible use as redox proxy.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologySodalite
DS201112-0433
2011
Markl, G.Hettmann, K., Marks, M., Kressing, K., Zack, T., Wenzel, T., Rehkamper, M., Jacob, D., Markl, G.The geochemistry of thallium and its isotopes in a peralkaline magmatic system.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologyMagmatism
DS201112-0604
2011
Markl, G.Lindhuber, M., Marks, M., Wenzel, T., Markl, G.Igneous layering in peralkaline rocks of the Ilmaussaq intrusion, Greenland.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GreenlandAlkalic
DS201112-0645
2011
Markl, G.Marks, M.A.W., Hettmann, K., Schilling, J., Frost, B.R., Markl, G.The mineralogical diversity of alkaline igneous rocks: critical factors for the transition from miaskitic to agpaitic phase assemblages.Journal of Petrology, Vol. 52, 3, pp. 439-455.Alkalic
DS201112-0846
2011
Markl, G.Ratschbacher, B., Pfaff, K., Marks, M., Markl, G.Geochemical trends within the lujavrites of the Ilmaussaq intrusion, SW Greenland.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GreenlandAlkalic
DS201112-0924
2011
Markl, G.Schilling, J., Marks, m.A.W., Wenzel, T., Vennenmann, T., Horvth, L., Tarassof, P., Jacob, D.E., Markl, G.The magmatic to hydrothermal evolution of the intrusive Mont Sainte Hilaire Complex: insights into the late stage evolution of peralkaline rocks.Journal of Petrology, Vol. 52, 11. pp. 2147-2185.Canada, QuebecAlkaline rocks, carbonatite
DS201112-0932
2011
Markl, G.Schmidt, P., Smith, D., Markl, G.The Eldor carbonatite complex, Quebec, Canada.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterCanada, QuebecCarbonatite
DS201112-0938
2011
Markl, G.Setzer, F., Worgard, L., Wenzel, T., Markl, G.Element mobilization in the Agate Mountain carbonatite complex, NW Namibia.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.136-137.Africa, NamibiaAgate
DS201112-0939
2011
Markl, G.Setzer, F., Worgard, L., Wenzel, T., Markl, G.Element mobilization in the Agate Mountain carbonatite complex, NW Namibia.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.136-137.Africa, NamibiaNews item - Agate
DS201112-0958
2011
Markl, G.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
DS201112-1151
2011
Markl, G.Zaitsev, A.N., Wenzel, T., Markl, G.Natrocarbonatites at Sadiman and Tinderent volcanoes, East African Rift - myth or reality?Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.161-163.Africa, KenyaCarbonatite
DS201112-1152
2011
Markl, G.Zaitsev, A.N., Wenzel, T., Markl, G.Natrocarbonatites at Sadiman and Tinderent volcanoes, East African Rift - myth or reality?Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.161-163.Africa, KenyaCarbonatite
DS201312-0952
2013
Markl, G.Wang, L., Wenzel, T., Vonder Handt, A., Keller, J., Marks, M.A.W., Markl, G.Compositional variation in apatites from carbonatites and associated silicate rocks: a case study of the Kaiserstuhl complex, Germany.Goldschmidt 2013, 1p. AbstractEurope, GermanyCarbonatite
DS201312-1004
2013
Markl, G.Zaitsev, A.N., Wenzel, T., Vennemann, T., Markl, G.Tinderet volcano, Kenya: an altered natrocarbonatite locality?Mineralogical Magazine, Vol. 77, 3, pp. 213-226.Africa, KenyaCarbonatite
DS201412-0545
2014
Markl, G.Mangler, M.F., Marks, M.A.W., Zaitsev, A.N., Eby, G.N., Markl, G.Halogens (F, Cl and Br) at Oldoinyo Lengai volcano ( Tanzania): effects of magmatic differentiation, silicate, natrocarbonatite melt seperation and surface alteration of natrocarbonatite.Chemical Geology, Vol. 365, pp. 43-53.Africa, TanzaniaCarbonatite
DS201412-0962
2014
Markl, G.Wang, L-X., Marks, M.A.W., Wenzel, T., Vonder Handt, A., Keller, J., Teiber, H., Markl, G.Apatites from the Kaiserstuhl volcanic complex, Germany: new constraints on the relationship between carbonatite and associated silicate rocks.European Journal of Mineralogy, Vol. 26, pp. 397-414.Europe, GermanyCarbonatite
DS201604-0617
2016
Markl, G.Ladenburger, S., Marks, M.A.W., Upton, B., Hill, P., Wenzel, T., Markl, G.Compositional variation of apatite from rift related alkaline igneous rocks of the Gardar Province, South Greenland.American Mineralogist, Vol. 101, pp. 612-626.Europe, GreenlandAlkalic

Abstract: Textural and compositional variations of apatite from four intrusions with different characteristic features of the rift-related alkaline Gardar Province were investigated: dyke rocks that belong to the most primitive rocks of the Province (Isortoq), nepheline-syenites associated with a carbonatite (Grønnedal-Ika), SiO2-saturated and SiO2-oversaturated syenites (Puklen) and nepheline-syenites displaying the transition from miaskitic to agpaitic mineral assemblages (Motzfeldt, Fig.1). Additionally, apatites from these intrusions were compared with other apatites of the Gardar Province. These include apatites from the Older Giant Dyke Complex, the Younger Giant Dyke Complex (both from the Tugtutôq region) and a narsarsukite-bearing trachytic dyke (Igdlutalik), as well as apatites from the Kûngnât, the North Qôroq and the Ilímaussaq intrusive complexes. This results in a complete overview of rift-related magmatites of the Gardar Province, ranging from primitive to highly evolved rocks. Backscattered electron images reveal the presence of various types of apatite textures including (i) growth zonation (concentric and oscillatory) that formed during magmatic differentiation and (ii) overgrowth and secondary textures (rounded cores, patchy zonation and overgrowth rims) due to fluid/melt induced metasomatic overprint and intracrystalline diffusion (Fig.2). Additionally, apatite compositions were analyzed with wavelength-dispersive electron microprobe analyses. During the crystallization history of the different intrusions, as well as within samples (documented by zoning patterns), increasing concentrations are observed for Si, REE, Na and F, whereas Cl shows a decreasing trend. However, for F, Cl and Na these trends are only observed in dyke rocks. Compositional variation of the investigated apatites is mainly due to substitution of Ca and P by variable amounts of Si, Na and REE. This study reveals that variations in the chemical composition of apatite are useful tools to obtain geochemical information about the host magma and its magmatic evolution. Here, Si and REE were found to be reliable petrogenetic indicators, whereas Na, F and Cl are only applicable in fast cooling systems to avoid redistribution of those elements.
DS201707-1326
2017
Markl, G.Giebel, R.J., Gauert, C.D.K., Marks, M.A.W., Costin, G., Markl, G.Multi stage formation of REE minerals in the Palabora carbonatite complex, South Africa.American Mineralogist, Vol. 102, pp. 1218-1233.Africa, South Africacarbonatite - Palabora

Abstract: The 2060 Ma old Palabora Carbonatite Complex (PCC), South Africa, comprises diverse REE mineral assemblages formed during different stages and reflects an outstanding instance to understand the evolution of a carbonatite-related REE mineralization from orthomagmatic to late-magmatic stages and their secondary post-magmatic overprint. The 10 rare earth element minerals monazite, REE-F-carbonates (bastnäsite, parisite, synchysite), ancylite, britholite, cordylite, fergusonite, REE-Ti-betafite, and anzaite are texturally described and related to the evolutionary stages of the PCC. The identification of the latter five REE minerals during this study represents their first described occurrences in the PCC as well as in a carbonatite complex in South Africa. The variable REE mineral assemblages reflect a multi-stage origin: (1) fergusonite and REE-Ti-betafite occur as inclusions in primary magnetite. Bastnäsite is enclosed in primary calcite and dolomite. These three REE minerals are interpreted as orthomagmatic crystallization products. (2) The most common REE minerals are monazite replacing primary apatite, and britholite texturally related to the serpentinization of forsterite or the replacement of forsterite by chondrodite. Textural relationships suggest that these two REE-minerals precipitated from internally derived late-magmatic to hydrothermal fluids. Their presence seems to be locally controlled by favorable chemical conditions (e.g., presence of precursor minerals that contributed the necessary anions and/or cations for their formation). (3) Late-stage (post-magmatic) REE minerals include ancylite and cordylite replacing primary magmatic REE-Sr-carbonates, anzaite associated with the dissolution of ilmenite, and secondary REE-F-carbonates. The formation of these post-magmatic REE minerals depends on the local availability of a fluid, whose composition is at least partly controlled by the dissolution of primary minerals (e.g., REE-fluorocarbonates). This multi-stage REE mineralization reflects the interplay of magmatic differentiation, destabilization of early magmatic minerals during subsequent evolutionary stages of the carbonatitic system, and late-stage fluid-induced remobilization and re-/precipitation of precursor REE minerals. Based on our findings, the Palabora Carbonatite Complex experienced at least two successive stages of intense fluid–rock interaction.
DS201811-2617
2018
Markl, G.Walter, B.F., Parsapoor, A., Braunger, S., Marks, M.A.W., Wenzel, T., Martin, M., Markl, G.Pyrochlore as a monitor for magmatic and hydrothermal processes in carbonatites from the Kaiserstuhl volcanic complex ( SW Germany).Chemical Geology, Vol. 498, pp. 1-16.Europe, Germanycarbonatite

Abstract: Pyrochlore from the Kaiserstuhl volcanic complex (SW Germany) shows textural and compositional differences between various coarse-grained calcite-carbonatite bodies (Badberg, Degenmatt, Haselschacher Buck, Orberg) and extrusive carbonatites (Henkenberg, Kirchberg). Oscillatory-zoned F-rich pyrochlore with up to 69?wt% Nb2O5 is common in all coarse-grained calcite-carbonatite bodies and probably formed during magmatic conditions. However, only in some of the samples from the Badberg, partly resorbed U- and Ta-enriched pyrochlore cores with up to 22?wt% UO2 and 9?wt% Ta2O5 have been identified, which are interpreted as being inherited from underlying nosean syenites. Pyrochlore data from a drill core penetrating the Badberg indicate increasing contents of REE, U, and Ta with depth, while Nb, F and Na contents decrease. This may reflect the combined effects of fractional crystallization and assimilation (AFC) or indicates a multi-stage emplacement of the carbonatitic magma. Patchy-zoned ceriopyrochlore and REE- and Th-enriched pyrochlore with up to 19?wt% total REE2O3 and 6.5?wt% ThO2 is largely restricted to samples from the Orberg and probably formed during hydrothermal conditions. This can be related to the relatively evolved character of the Orberg carbonatites, based on their relatively high whole-rock Nb/Ta and Zr/Hf mass ratios. This study demonstrates that the textural and compositional variation of pyrochlore in carbonatites is a powerful tool to distinguish magmatic, hydrothermal and weathering processes in carbonatitic systems.
DS201812-2810
2019
Markl, G.Giebel, R.J., Marks, M.A.W., Gauert, C.D.K., Markl, G.A model for the formation of carbonatite-phoscorite assemblages based on the compositional variations of mica and apatite from the Palabora carbonatite complex, South Africa.Lithos, Vol. 324-325, pp. 89-104.Africa, South Africadeposit - Palabora

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

Abstract: A detailed electron microprobe study has been carried out on the compositional variations of mica and apatite from carbonatites, phoscorites and associated pyroxenites (and fenites) of the Loolekop deposit, Palabora Carbonatite Complex (South Africa). Mica in pyroxenites and fenites is Mg-rich biotite, whilst micas in carbonatites and phoscorites are compositionally diverse including phlogopite, Ba-rich phlogopite (up to 30% kinoshitalite component), IVAl-rich phlogopite (up to 30% eastonite component) and tetraferriphlogopite. The various types of phlogopites are interpreted as orthomagmatic phases, whereas tetraferriphlogopite precipitation was a late-magmatic to hydrothermal process that additionally introduced REE into the system. Orthomagmatic apatite is generally REE- and Sr-poor fluorapatite and does not show large compositional differences between rock types. Apatite associated with the late-stage tetraferriphlogopite mineralization reaches higher levels of REE (up to 4.9?wt%), Si (up to 1.5?wt% SiO2), Sr (up to 2.6?wt% SrO) and Na (up to 1.0?wt% Na2O). The compositional variation of micas and apatites, which is affiliated with distinct rock types, reflects the multi-stage evolution of the Loolekop deposit and provides detailed insight into the relationships of the carbonatite-phoscorite assemblage. The obtained data support the separation of phoscorite and carbonatite by immiscibility from a common parental magma, which may happen due to a decrease of temperature and/or pressure during the ascent of the magma. This results in a density contrast between the carbonatitic and phoscoritic components that will lead to descending phoscorite accumulations at the outer zones of the magma channel and a jet-like ascent (further promoted by its extremely low viscosity) of the carbonatite magma. The genetic model deduced here explains the peculiar association of carbonatites, phoscorites and silicate rocks in many alkaline complexes worldwide.
DS201909-2024
2019
Markl, G.Braunger, S., Marks, M.A.W., Wenzel, T., Chmyz, L., Azzone, R.G., Markl, G.Carbonatite-alkaline silica rock complexes reflect highly oxidized conditions in their Upper Mantle source.Goldschmidt2019, 1p. AbstractMantlecarbonatite

Abstract: Alkaline complexes consist of variable mantle-derived silicate rocks, ranging from primitive alkali basalts, melilitites, nephelinites and basanites towards tephrites and more evolved phonolites, respectively their plutonic equivalents. This lithological variance is also expressed by a wide range of redox conditions that vary by several log units around the synthetic fayalite-magnetite-quartz (FMQ) buffer. However, only some of these complexes are characterized by the occurrence of carbonatites which must be related to specific formation conditions. Based on textural, mineralogical and geochemical observations, we calculated the redox conditions of carbonatites and associated silicate rocks for seven alkaline complexes (Kaiserstuhl, Sokli, Kovdor, Palabora, Magnet Cove, Oka, Jacupiranga) which are considered to represent typical carbonatite-alkaline silicate rock associations. In combination with a comprehensive literature review, we demonstrate that carbonatite-bearing alkaline complexes formed under highly oxidized conditions and hence, belong to the most oxidized alkaline rocks at all. This is consistent with the prerequisite of a carbonated mantle as the source region for carbonatite complexes, which requires redox conditions distinctively above that for mean lithospheric or asthenospheric mantle. Carbonatitemetasomatized peridotites also show high redox conditions and might not only reflect an interaction between peridotite and carbonatitic melts/fluids, but at least partly represent the carbonated mantle source for crustally emplaced carbonatite complexes. We therefore suggest that the oxidation state of carbonatites and associated silicate rocks provides direct information about an extraordinary oxidized parental mantle source.
DS201909-2041
2019
Markl, G.Giebel, R.J., Marks, M.A.W., Gauert, C.D.K., Markl, G.A model for the formation of carbonatite-phoscorite assemblages.Goldschmidt2019, 1p. AbstractGlobalcarbonatite

Abstract: A detailed electron microprobe study has been carried out on the compositional variations of mica and apatite from carbonatites, phoscorites and associated pyroxenites (and fenites) of the Loolekop deposit, Palabora Carbonatite Complex (South Africa). Mica in pyroxenites and fenites is Mg-rich biotite, whilst micas in carbonatites and phoscorites are compositionally diverse including phlogopite, Ba-rich phlogopite (up to 30% kinoshitalite component), IVAl-rich phlogopite (up to 30% eastonite component) and tetraferriphlogopite. The various types of phlogopites are interpreted as orthomagmatic phases, whereas tetraferriphlogopite precipitation was a late-magmatic to hydrothermal process that additionally introduced REE into the system. Orthomagmatic apatite is generally REE- and Sr-poor fluorapatite and does not show large compositional differences between rock types. Apatite associated with the late-stage tetraferriphlogopite mineralization reaches higher levels of REE (up to 4.9?wt%), Si (up to 1.5?wt% SiO2), Sr (up to 2.6?wt% SrO) and Na (up to 1.0?wt% Na2O). The compositional variation of micas and apatites, which is affiliated with distinct rock types, reflects the multi-stage evolution of the Loolekop deposit and provides detailed insight into the relationships of the carbonatite-phoscorite assemblage. The obtained data support the separation of phoscorite and carbonatite by immiscibility from a common parental magma, which may happen due to a decrease of temperature and/or pressure during the ascent of the magma. This results in a density contrast between the carbonatitic and phoscoritic components that will lead to descending phoscorite accumulations at the outer zones of the magma channel and a jet-like ascent (further promoted by its extremely low viscosity) of the carbonatite magma. The genetic model deduced here explains the peculiar association of carbonatites, phoscorites and silicate rocks in many alkaline complexes worldwide.
DS201909-2050
2019
Markl, G.Hutchison, W., Baiel, R., Finch, A., Marks, M., Markl, G., Boyce, A., Stueken, E., Friis, H., Borst, A., Horsburgh, N.Sulphur isotopes of alkaline igneous suites: new insights into magmatic fluid evolution and crustal recycling.Goldschmidt2019, 1p. AbstractGlobalalkaline rocks
DS201909-2061
2019
Markl, G.Marks, M.A.W., Giebel, R.J., Walter, B.F., Braunger, S., Wenzel, T., Markl, G.Evidence for wall-rock assimilation in carbonatites from the Kaiserstuhl (German).Goldschmidt2019, 1p. AbstractEurope, Germanydeposit - Kaiserstuhl

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

Abstract: Studies on fluid inclusions in carbonatitic rocks are essential to understand the physicochemical processes involved in carbonatite-related hydrothermal ore mineralization. Although little is known about the composition of carbonatite-derived fluids. We investigated fluid inclusions in the Kaiserstuhl carbonatites, SW Germany [1,2] and identified four different types typically known from carbonatitic systems worldwide [3]: (I): Vapor-poor H2O-NaCl fluids with <50 wt.% salinity. (II): Vapor-rich H2O-NaCl-CO2 fluids with <5 wt.% salinity. (III): Multi-component fluids with high salinity and CO2. (IV): Multi-component fluids with high salinity, no CO2. Homogenization temperatures (156 to 530°C) of all fluid types generally show a wide range [this study, 2]. Primary type I fluid inclusions occur in early magmatic olivine/monticellite, as well as paragenetically later apatites and calcites [2]. This indicates a ubiquitous existence of a saline brine, which does not reach saturation with respect to halite, during early to late crystallization stages. Liquidus surface modelling based quantifications for fluid type III suggest that carbonatite melts predomonantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (type III or IV, respectively). Such fluid inclusions, with type III (CO2-free) on one side and type IV (and II, both CO2-rich) on the other side, may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, is probably triggered by a rapid pressure release during “pneumatic hammer-like,” discontinuous melt ascent.
DS202002-0168
2020
Markl, G.Braunger, S., Marks, M.A.W., Wenzel, T., Chmyz, L., Azzone, R.G., Markl, G.Do carbonatites and alkaline rocks reflect variable redox conditions in their upper mantle source? ( metasomatism)Earth and Planetary Science Letters, Vol. 533, 11p. PdfMantlecarbonatite

Abstract: A detailed investigation on seven carbonatites and associated alkaline rock complexes (Kaiserstuhl, Sokli, Kovdor, Palabora, Oka, Magnet Cove, Jacupiranga), together with a world-wide comparison between carbonatites, alkaline silicate rocks and mantle xenoliths, implies peculiar redox conditions for carbonatite-bearing alkaline complexes: Carbonatites and associated alkaline rocks in continental settings crystallize from relatively oxidized magmas, on average 1.4 log units () and 1.3 log units () above the synthetic fayalite-magnetite-quartz (FMQ) buffer. In contrast, alkaline rocks in continental settings that lack associated carbonatites reveal rather reduced conditions (mean ; ). The calculated redox conditions for carbonatites and associated silicate rocks demonstrate that these crystallize from relatively oxidized mantle-derived melts compared to the general range found for alkaline rocks in continental settings.
DS202006-0955
2020
Markl, G.Walter, B.F., Steele-MacInnis, M., Giebel, R.J., Marks, M.A.W., Markl, G.Complex carbonatite-sulfate brines in fluid inclusions from carbonatites: estimating compositions in the system H2O-Na-K-CO3-SO4-Cl. KaiserstuhlGeochimica et Cosmochimica Acta, Vol. 277, pp. 224-242. pdfEurope, Germanycarbonatite

Abstract: Studies of fluid inclusions in carbonatitic rocks are essential for understanding physicochemical processes involved in carbonatite-related hydrothermal ore mineralization and fenitization. However, the composition of many carbonatite-derived fluids is challenging to quantify, which hampers their detailed interpretation. Here, we present a systematic study of microthermometry of fluid inclusions found in carbonatites from the Kaiserstuhl (SW Germany), and a simple numerical model to estimate the compositions of such fluids, which are typical of numerous carbonatites worldwide. Four types of fluid inclusions have been identified in the Kaiserstuhl carbonatites: (I) vapor-poor H2O-NaCl fluids with <50?wt.% salinity; (II) vapor-rich H2O-NaCl-CO2 fluids with <5?wt.% salinity; (III) multi-component fluids with high salinity and high CO2 contents; and (IV) multi-component fluids with high salinity but little to no CO2. At present, it is only possible to quantify fluid compositions for types I and II. For the complex types III and IV, we conducted predictive modeling of the liquidus surface based on the Margules equations. The results suggest that carbonatite melts predominantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (types III or IV). Such fluid inclusions may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, was probably triggered by a rapid pressure release during melt ascent. The present model enables quantification of fluid compositions associated with carbonatitic magmatism.
DS202007-1145
2020
Markl, G.Hecker, J.G., Marks, M.A.W., Wenzel, T., Markl, G.Halogens in amphibole and mica from mantle xenoliths: implications for the halogen distribution and halogen budget of the metasomatized continental lithosphere.American Mineralogist, Vol. 105, pp. 781-794.Mantlemetasomatism

Abstract: This study reports halogen contents (F and Cl) of amphibole and phlogopite derived from mantle xenoliths and one peridotite massif, for amphibole and phlogopite megacrysts and ultramafic magmatic cumulates (hornblendites) found in alkaline volcanic rocks from 12 localities in Europe and Africa. Amphibole and phlogopite contain more F than Cl with F/Cl ratios reaching about 160 in phlogopites and 50 in amphiboles. Phlogopites are higher in F (median of 3400 µg/g) than amphibole (median of 1000 µg/g), while median Cl contents are higher in amphibole (290 µg/g) compared to phlogopite (180 µg/g). The Cl contents and the F/Cl ratios in amphibole and phlogopite from mantle xenoliths exhibit large differences between samples of the same region, recording very large variations of halogen contents in the continental lithosphere. We suggest that the halogen content in such samples largely depends on the initial composition of percolating melts and fluids in the continental lithosphere. During reaction of these agents with peridotitic wall-rocks, Cl is preferentially retained in the fluid as it is much more incompatible compared to water and F. This desiccation effect continuously increases salinity (Cl content) and decreases the F/Cl ratio in the agent with time, causing variable Cl contents and F/Cl ratios in amphibole and phlogopite at a specific locality. Subsequent partial melting processes may then sequester and re-distribute, especially Cl among amphibole, phlogopite and melts/fluids as a result of its strong incompatibility, whereas F is much less affected as it behaves slightly compatible. The impact of even small amounts of amphibole and mica on the total halogen budget in the continental lithosphere is significant and both minerals can effectively contribute to the high halogen contents typical of alkaline melts.
DS202007-1184
2020
Markl, G.Walter, B.F., Steele-MacInnis, M., Gielbel, R.J., Marks, M.A.W., Markl, G.Complex carbonatite-sulfate brines in fluid inclusions from carbonatites: estimating compositions in the system H2O-Na-K-CO3-SO4-ClGeochimica et Cosmochimica Acta, Vol. 277, pp. 224-242. pdfEurope, Germanydeposit - Kaiserstuhl

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

Abstract: Carbonatites are formed from volatile-rich melts, commonly associated with a characteristic hydrothermal footprint. However, studies of their fluid inclusions are relatively scarce and heterogeneous in terms of detail and completeness of the data presented. Here, we review and discuss comprehensively the results of previous studies and derive a general model for the formation and properties of fluids associated with carbonatitic magmatism. Worldwide, four types of fluid inclusion occur in carbonatites: (type I/HS) vapour-poor H2O-NaCl fluids with up to 50 wt% salinity; (type II/HC) vapour-rich H2O-NaCl-CO2 fluids with <5 wt% salinity; (type III/DS) multi-component fluids with high salinity and without CO2; and (type IV/CDS) multi-component fluids with high salinity and high CO2. This global dataset suggests continuous fluid release from deep to shallow-level intrusions. Modelling of the liquidus surface indicates that carbonatite magmas generally exsolve a saline brine (type I/HS). This brine separates/evolves into a Na-K-sulfate-carbonate/bicarbonate-chloride brine with or without CO2 (types III/DS and IV/CDS), trapped together with low salinity CO2-rich fluids produced by immiscibility. Fluid immiscibility is related to rapid pressure release during fast, forceful and discontinuous magma ascent, which we envisage as a "pneumatic jackhammer" model for carbonatite ascent and emplacement. In this model, cyclic and progressive fluid flux via pressure build-up and subsequent catastrophic pressure release results in a self-sustaining crustal ascent of the buoyant, low-viscosity magma. This process allows for rapid and efficient magma ascent, in particular above the brittle-ductile transition zone, where pressures that prevailed during apatite crystallization have been estimated in numerous complexes. Moreover, this model provides an explanation for the apparent absence of shallow carbonatite magma chambers (in a classical sense) and identifies fenitization as a phenomenon induced by both fluids released during magma ascent and residual fluids.
DS1995-1896
1995
Markley, M.Teyssier, C., Tikoff, B., Markley, M.Oblique plate motion and continental tectonicsGeology, Vol. 23, No. 5, May pp. 447-450GlobalStructure, Tectonics
DS200512-0340
2004
Markley, M.Giorgis, S., Markley, M., Tikoff, B.Vertical axis rotation of rigid crustal blocks driven by mantle flow.Geological Society of London Special Paper, No. 226, pp. 83-100.MantleTectonics
DS200812-0714
2008
Markner-Jager, B.Markner-Jager, B.Technical english for geosciences. A textbook/workbook.Springer, 78p. $ 50.00GlobalBook - terminology/english/geosciences
DS1984-0481
1984
Marko, K.A.Marko, K.A.Takomkane, an Unusual Basanite in Eastern British ColumbiaBsc. Thesis, Brock University of St. Catherines Ontario, 32pBritish ColumbiaBasanite
DS201212-0265
2012
Marko, L.Grutter, H.S., Gerdes, A., Marko, L., Heaman, L.M.U-Pb geochronology of perovskite and zircon from the Chigicherla kimberlites, Anatapur district, India.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractIndiaDeposit - Chigicherla
DS1987-0587
1987
Markov, A.S.Podvysotskiy, V.T., Markov, A.S.Ilmenite and titanomagnetite in rocks of the Traprock association in the Malaya Botuobuya and the Alakit-Markha kimberlite fields, YakutiaDoklady Academy of Science USSR, Earth Science Section, Vol. 297, No. 6, Nov-Dec., pp. 144-148RussiaIlmenites, Titanomagnetite
DS200412-1874
2004
Markova, M.E.Soloveva, L.V., Gornova, M.A., Markova, M.E., Lozhkin, V.I.Geochemical identification of granulites in xenoliths from Yakutian kimberlites.Geochemistry International, Vol. 42, 3, pp. 220-235.Russia, YakutiaGeochemistry
DS201903-0530
2018
Markovets, V.Markovets, V.Diamond deposits exploration, scientific and research report.7th Symposio Brasleiro de geologia do diamante, 68 ppts. AvailableSouth America, Brazildiamond geology
DS200812-0589
2008
Markovic, G.Kopylova, M.G., Nowell, G.M., Pearson, D.G., Markovic, G.Crystallization of megacrysts from kimberlites: geochemical evidence from high Cr megacrysts in the Jericho kimberlite.9IKC.com, 3p. extended abstractCanada, NunavutDeposit - Jericho
DS200912-0405
2009
Markovic, G.Kopylova, M.G., Nowell, G.M., Pearson, D.G., Markovic, G.Crystallization of megacrysts from protokimberlitic fluids: geochemical evidence from high - Cr megacrysts in the Jericho kimberlite.Lithos, In press - available 51p.Canada, NunavutDeposit - Jericho
DS201112-0643
2007
Markovic, G.Markovic, G.The age and origin of megacrysts in the Jericho kimberlite, Nunavut Canada.University of British Columbia, Msc. thesis, 100p.Canada, NunavutThesis - note availability based on request via author
DS1981-0088
1981
Markovskiy, A.A.Bogdasarov, E.A., Landa, E.A., Markovskiy, A.A.Chemical Composition and Crystallization Conditions of Chrome Spinels of Volcanic Ultramafics and Other Rocks of the Mafic Ultramafic Series.International Geology Review, Vol. 23, No. 9, PP. 931-RussiaKimberlite, Spinels, Mineralogy
DS1970-0345
1971
Markovskiy, B.A.Markovskiy, B.A., Rotman, V.K.Geosynclinal Meymechite of KamchatkaDoklady Academy of Science USSR, Earth Science Section., Vol. 196, No. 1-6, PP. 158-161.RussiaKimberlite
DS1983-0383
1983
Markovskiy, B.A.Landa, E.A., Lyapunov, S.M., Markovskiy, B.A.Characteristics of rare earth distribution in volcanicultrabasites.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 272, No. 2, pp. 462-464RussiaKamchatka Pen., Anabar Shield, Meymechite, Picrite, Rare Earth
DS201811-2553
2018
Markovsky, B.A.Badredinov, Z.G., Markovsky, B.A., Tararin, I.A., Ekimova, N.I., Chubarov, V.M.Fluid silicate seperation of an ultrabasic melt into high potassium and low potassium fractions: evidence from picrites of the Late Cretaceous ultrabasic volcanic complex, eastern Kamchatka.Russian Journal of Pacific Geology, Vol. 12, 5, pp. 408-418.Russia, Kamchatkapicrites

Abstract: The mineral and chemical compositions of the layered subvolcanic ultrabasic rocks formed through fluid-silicate (liquid) separation of the ultrabasic magma into high-potassium and low-potassium fractions are characterized by the example of the layered picritic sill from the Late Cretaceous ultrabasic volcanic complex of Eastern Kamchatka. It is determined that the main potassium concentrator in the picrites from the high-potassium layers is a residual volcanic glass containing up to 8-9 wt % K2O, which is unique for ultrabasic melts.
DS201212-0096
2012
Marks, A.Bulanova, G.P., Marks, A., Smith, C.B., Kohn, S.C., Walter, M.J., Gaillou, E., Shiry, S.B., Trautman, R., Griffin, B.J.Diamonds from Sese and Murowa kimberlites ( Zimbabwe) - evidence of extreme peridotitic lithosphere depletion and Ti-REE metasomatism.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, ZimbabweDeposit - Sese, Murowa
DS201212-0367
2012
Marks, A.Kohn, S.C., McKay, A.P., Smith, C.B., Bulanova, G.P., Walter, M.J., Marks, A.The thermal history of Archean lithosphere. Constraints from FTIR studies of zoning in diamonds.emc2012 @ uni-frankfurt.de, 1p. AbstractAfrica, ZimbabweDeposit - Murowa
DS201812-2784
2018
Marks, A.Bulanova, G.P., Smith, C.B., Pearson, D.G., Kohn, S.C., Davy, A.T., McKay, A., Marks, A.Murowa deposit: Diamonds from the Murowa kimberlites: formation within extremely depleted and metasomatized Zimbabwean peridotitic subcontinental mantle.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 425-Africa, Zimbabwedeposit - Murowa
DS1981-0312
1981
Marks, G.P.Nichols, I.A., Ferguson, J., Jones, H., Marks, G.P., Mutter, J.C.Ultramafic Blocks from the Ocean Floor Southwest of AustraliEarth and Planetary Science Letters, Vol. 56, PP. 362-374.Australia, Western AustraliaUltrabasic, Rocks, Lherzolite, Sea Floor Dredging
DS1984-0484
1984
Marks, J.Marrs, R.W., Marks, J., Hausel, W.D., Albert, K.G.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Province. #2Nasa Jet Propulsion Laboratory, Final Report Dated Sept. 28t, 70P.United States, Colorado, Wyoming, State Line, Rocky MountainsRemote Sensing, Geochemistry, Sampling, Prospecting, Geophysics
DS1983-0433
1983
Marks, J.E.Marks, J.E., Marrs, R.W.Remote Sensing Exploration for Poorly Exposed Kimberlite In the Colorado-Wyoming Region.Geological Survey WYOMING, Publishing INF. Circular No. 19, PP. 11-13.United States, Colorado, Wyoming, State Line, Rocky MountainsLandsat
DS1984-0485
1984
Marks, J.E.Marrs, R.W., Marks, J.E., Hausel, W.D., Albert, G.K.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Province. #1International Symposium on Remote Sensing of Environment., THIRD THEMATIC CONFERENCE, APRIL 16TH.-19TH. 11P.United States, State Line, Colorado, WyomingLandsat, Remote Sensing, Geophysics, Analyses, Diatreme
DS1985-0414
1985
Marks, J.E.Marks, J.E.Multispectral Remote Sensing Techniques Applied to Exploration for Kimberlite Distremes, Laramie Range, Wyoming-colorado.Msc. Thesis, University Wyoming, 164P.United States, State Line, Colorado, Wyoming, Laramie RangeRemote Sensing
DS2001-0732
2001
Marks, K.M.Marks, K.M., Tikku, A.A.Cretaceous reconstructions of the East Antarctica, Africa and MadagascarEarth and Planetary Science Letters, Vol. 186, No. 3-4, Apr. 15, pp. 479-96.Madagascar, Africa, AntarcticaTectonics, Gondwana
DS201112-0266
2011
Marks, M.Derrey, I., Hettmann, K., Thaler, F., Wenzel, T., Marks, M., Markl, G.Sulfur content and speciation in sodalite and its possible use as redox proxy.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologySodalite
DS201112-0369
2011
Marks, M.Giehl, C., Bellucci, P., Nguyen, H-T., Marks, M., Nowak, M.Experimental investigation of the differentiation of iron rich peralkaline magma.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologyMagmatism
DS201112-0433
2011
Marks, M.Hettmann, K., Marks, M., Kressing, K., Zack, T., Wenzel, T., Rehkamper, M., Jacob, D., Markl, G.The geochemistry of thallium and its isotopes in a peralkaline magmatic system.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologyMagmatism
DS201112-0604
2011
Marks, M.Lindhuber, M., Marks, M., Wenzel, T., Markl, G.Igneous layering in peralkaline rocks of the Ilmaussaq intrusion, Greenland.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GreenlandAlkalic
DS201112-0644
2011
Marks, M.Marks, M.Critical factors for the transition from miaskitic to agpaitic rocks: the role of f02,Na2O and K2O and CaO.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, AbstractGeochemistry
DS201112-0846
2011
Marks, M.Ratschbacher, B., Pfaff, K., Marks, M., Markl, G.Geochemical trends within the lujavrites of the Ilmaussaq intrusion, SW Greenland.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterEurope, GreenlandAlkalic
DS201909-2050
2019
Marks, M.Hutchison, W., Baiel, R., Finch, A., Marks, M., Markl, G., Boyce, A., Stueken, E., Friis, H., Borst, A., Horsburgh, N.Sulphur isotopes of alkaline igneous suites: new insights into magmatic fluid evolution and crustal recycling.Goldschmidt2019, 1p. AbstractGlobalalkaline rocks
DS202109-1494
2021
Marks, M.A.Walter, B.F., Giebel, R.J., Steele-MacInnis, M., Marks, M.A., Kolb, J., Markl, G.Fluids associated with carbonatitic magmatism: a critical review and implications for carbonatite magma ascent.Earth Science Reviews , Vol. 215, 103509, 27p. PdfMantlemagmatism

Abstract: Carbonatites are formed from volatile-rich melts, commonly associated with a characteristic hydrothermal footprint. However, studies of their fluid inclusions are relatively scarce and heterogeneous in terms of detail and completeness of the data presented. Here, we review and discuss comprehensively the results of previous studies and derive a general model for the formation and properties of fluids associated with carbonatitic magmatism. Worldwide, four types of fluid inclusion occur in carbonatites: (type I/HS) vapour-poor H2O-NaCl fluids with up to 50 wt% salinity; (type II/HC) vapour-rich H2O-NaCl-CO2 fluids with <5 wt% salinity; (type III/DS) multi-component fluids with high salinity and without CO2; and (type IV/CDS) multi-component fluids with high salinity and high CO2. This global dataset suggests continuous fluid release from deep to shallow-level intrusions. Modelling of the liquidus surface indicates that carbonatite magmas generally exsolve a saline brine (type I/HS). This brine separates/evolves into a Na-K-sulfate-carbonate/bicarbonate-chloride brine with or without CO2 (types III/DS and IV/CDS), trapped together with low salinity CO2-rich fluids produced by immiscibility. Fluid immiscibility is related to rapid pressure release during fast, forceful and discontinuous magma ascent, which we envisage as a "pneumatic jackhammer" model for carbonatite ascent and emplacement. In this model, cyclic and progressive fluid flux via pressure build-up and subsequent catastrophic pressure release results in a self-sustaining crustal ascent of the buoyant, low-viscosity magma. This process allows for rapid and efficient magma ascent, in particular above the brittle-ductile transition zone, where pressures that prevailed during apatite crystallization have been estimated in numerous complexes. Moreover, this model provides an explanation for the apparent absence of shallow carbonatite magma chambers (in a classical sense) and identifies fenitization as a phenomenon induced by both fluids released during magma ascent and residual fluids.
DS200712-0681
2007
Marks, M.A.W.Marks, M.A.W., Rudnick, R.L., McCammon, C., Vennemann, T., Markl, G.Arrested kinetic Li isotope fractionation at the margin of the Ilimaussaq complex: evidence for open system processes during final cooling peralkaline igneous rocksChemical Geology, Vol. 246, 3-4, pp. 207-230.Europe, GreenlandGeochronology
DS200912-0473
2009
Marks, M.A.W.Marks, M.A.W., Neukirchen, F., Vennemann, T., Markl, G.Textural, chemical and isotopic effects of late magmatic carbonatitic fluids in the carbonatite syenite Tamazeght complex, High Atlas Mountains, Morocco.Mineralogy and Petrology, Vol. 97, pp. 23-42.Africa, MoroccoCarbonatite
DS201112-0645
2011
Marks, M.A.W.Marks, M.A.W., Hettmann, K., Schilling, J., Frost, B.R., Markl, G.The mineralogical diversity of alkaline igneous rocks: critical factors for the transition from miaskitic to agpaitic phase assemblages.Journal of Petrology, Vol. 52, 3, pp. 439-455.Alkalic
DS201112-0924
2011
Marks, m.A.W.Schilling, J., Marks, m.A.W., Wenzel, T., Vennenmann, T., Horvth, L., Tarassof, P., Jacob, D.E., Markl, G.The magmatic to hydrothermal evolution of the intrusive Mont Sainte Hilaire Complex: insights into the late stage evolution of peralkaline rocks.Journal of Petrology, Vol. 52, 11. pp. 2147-2185.Canada, QuebecAlkaline rocks, carbonatite
DS201212-0810
2012
Marks, M.A.W.Zaitsev, A.N., Marks, M.A.W., Wenzel, T., Spratt, W.J., Sharygin, V.V., Strekoptov, G.M.Mineralogy, geochemistry and petrology of the phonolitic to nephelinitic Sadiman volcano, Crater Highlands, Tanzania.Lithos, Vol. 152, pp. 66-83.Africa, TanzaniaNephelinite
DS201312-0952
2013
Marks, M.A.W.Wang, L., Wenzel, T., Vonder Handt, A., Keller, J., Marks, M.A.W., Markl, G.Compositional variation in apatites from carbonatites and associated silicate rocks: a case study of the Kaiserstuhl complex, Germany.Goldschmidt 2013, 1p. AbstractEurope, GermanyCarbonatite
DS201412-0545
2014
Marks, M.A.W.Mangler, M.F., Marks, M.A.W., Zaitsev, A.N., Eby, G.N., Markl, G.Halogens (F, Cl and Br) at Oldoinyo Lengai volcano ( Tanzania): effects of magmatic differentiation, silicate, natrocarbonatite melt seperation and surface alteration of natrocarbonatite.Chemical Geology, Vol. 365, pp. 43-53.Africa, TanzaniaCarbonatite
DS201412-0962
2014
Marks, M.A.W.Wang, L-X., Marks, M.A.W., Wenzel, T., Vonder Handt, A., Keller, J., Teiber, H., Markl, G.Apatites from the Kaiserstuhl volcanic complex, Germany: new constraints on the relationship between carbonatite and associated silicate rocks.European Journal of Mineralogy, Vol. 26, pp. 397-414.Europe, GermanyCarbonatite
DS201604-0617
2016
Marks, M.A.W.Ladenburger, S., Marks, M.A.W., Upton, B., Hill, P., Wenzel, T., Markl, G.Compositional variation of apatite from rift related alkaline igneous rocks of the Gardar Province, South Greenland.American Mineralogist, Vol. 101, pp. 612-626.Europe, GreenlandAlkalic

Abstract: Textural and compositional variations of apatite from four intrusions with different characteristic features of the rift-related alkaline Gardar Province were investigated: dyke rocks that belong to the most primitive rocks of the Province (Isortoq), nepheline-syenites associated with a carbonatite (Grønnedal-Ika), SiO2-saturated and SiO2-oversaturated syenites (Puklen) and nepheline-syenites displaying the transition from miaskitic to agpaitic mineral assemblages (Motzfeldt, Fig.1). Additionally, apatites from these intrusions were compared with other apatites of the Gardar Province. These include apatites from the Older Giant Dyke Complex, the Younger Giant Dyke Complex (both from the Tugtutôq region) and a narsarsukite-bearing trachytic dyke (Igdlutalik), as well as apatites from the Kûngnât, the North Qôroq and the Ilímaussaq intrusive complexes. This results in a complete overview of rift-related magmatites of the Gardar Province, ranging from primitive to highly evolved rocks. Backscattered electron images reveal the presence of various types of apatite textures including (i) growth zonation (concentric and oscillatory) that formed during magmatic differentiation and (ii) overgrowth and secondary textures (rounded cores, patchy zonation and overgrowth rims) due to fluid/melt induced metasomatic overprint and intracrystalline diffusion (Fig.2). Additionally, apatite compositions were analyzed with wavelength-dispersive electron microprobe analyses. During the crystallization history of the different intrusions, as well as within samples (documented by zoning patterns), increasing concentrations are observed for Si, REE, Na and F, whereas Cl shows a decreasing trend. However, for F, Cl and Na these trends are only observed in dyke rocks. Compositional variation of the investigated apatites is mainly due to substitution of Ca and P by variable amounts of Si, Na and REE. This study reveals that variations in the chemical composition of apatite are useful tools to obtain geochemical information about the host magma and its magmatic evolution. Here, Si and REE were found to be reliable petrogenetic indicators, whereas Na, F and Cl are only applicable in fast cooling systems to avoid redistribution of those elements.
DS201707-1326
2017
Marks, M.A.W.Giebel, R.J., Gauert, C.D.K., Marks, M.A.W., Costin, G., Markl, G.Multi stage formation of REE minerals in the Palabora carbonatite complex, South Africa.American Mineralogist, Vol. 102, pp. 1218-1233.Africa, South Africacarbonatite - Palabora

Abstract: The 2060 Ma old Palabora Carbonatite Complex (PCC), South Africa, comprises diverse REE mineral assemblages formed during different stages and reflects an outstanding instance to understand the evolution of a carbonatite-related REE mineralization from orthomagmatic to late-magmatic stages and their secondary post-magmatic overprint. The 10 rare earth element minerals monazite, REE-F-carbonates (bastnäsite, parisite, synchysite), ancylite, britholite, cordylite, fergusonite, REE-Ti-betafite, and anzaite are texturally described and related to the evolutionary stages of the PCC. The identification of the latter five REE minerals during this study represents their first described occurrences in the PCC as well as in a carbonatite complex in South Africa. The variable REE mineral assemblages reflect a multi-stage origin: (1) fergusonite and REE-Ti-betafite occur as inclusions in primary magnetite. Bastnäsite is enclosed in primary calcite and dolomite. These three REE minerals are interpreted as orthomagmatic crystallization products. (2) The most common REE minerals are monazite replacing primary apatite, and britholite texturally related to the serpentinization of forsterite or the replacement of forsterite by chondrodite. Textural relationships suggest that these two REE-minerals precipitated from internally derived late-magmatic to hydrothermal fluids. Their presence seems to be locally controlled by favorable chemical conditions (e.g., presence of precursor minerals that contributed the necessary anions and/or cations for their formation). (3) Late-stage (post-magmatic) REE minerals include ancylite and cordylite replacing primary magmatic REE-Sr-carbonates, anzaite associated with the dissolution of ilmenite, and secondary REE-F-carbonates. The formation of these post-magmatic REE minerals depends on the local availability of a fluid, whose composition is at least partly controlled by the dissolution of primary minerals (e.g., REE-fluorocarbonates). This multi-stage REE mineralization reflects the interplay of magmatic differentiation, destabilization of early magmatic minerals during subsequent evolutionary stages of the carbonatitic system, and late-stage fluid-induced remobilization and re-/precipitation of precursor REE minerals. Based on our findings, the Palabora Carbonatite Complex experienced at least two successive stages of intense fluid–rock interaction.
DS201802-0233
2018
Marks, M.A.W.Elliott, H.A.L., Wall, F., Chakmouradian, A.R., Siegfried, P.R., Dahlgren, S., Weatherley, S., Finch, A.A., Marks, M.A.W., Dowman, E., Deady, E.Fenites associated with carbonatite complexes: a review.Ore Geology Reviews, Vol. 92, pp. 38-59.Globalcarbonatites

Abstract: Carbonatites and alkaline-silicate rocks are the most important sources of rare earth elements (REE) and niobium (Nb), both of which are metals imperative to technological advancement and associated with high risks of supply interruption. Cooling and crystallizing carbonatitic and alkaline melts expel multiple pulses of alkali-rich aqueous fluids which metasomatize the surrounding country rocks, forming fenites during a process called fenitization. These alkalis and volatiles are original constituents of the magma that are not recorded in the carbonatite rock, and therefore fenites should not be dismissed during the description of a carbonatite system. This paper reviews the existing literature, focusing on 17 worldwide carbonatite complexes whose attributes are used to discuss the main features and processes of fenitization. Although many attempts have been made in the literature to categorize and name fenites, it is recommended that the IUGS metamorphic nomenclature be used to describe predominant mineralogy and textures. Complexing anions greatly enhance the solubility of REE and Nb in these fenitizing fluids, mobilizing them into the surrounding country rock, and precipitating REE- and Nb-enriched micro-mineral assemblages. As such, fenites have significant potential to be used as an exploration tool to find mineralized intrusions in a similar way alteration patterns are used in other ore systems, such as porphyry copper deposits. Strong trends have been identified between the presence of more complex veining textures, mineralogy and brecciation in fenites with intermediate stage Nb-enriched and later stage REE-enriched magmas. However, compiling this evidence has also highlighted large gaps in the literature relating to fenitization. These need to be addressed before fenite can be used as a comprehensive and effective exploration tool.
DS201811-2617
2018
Marks, M.A.W.Walter, B.F., Parsapoor, A., Braunger, S., Marks, M.A.W., Wenzel, T., Martin, M., Markl, G.Pyrochlore as a monitor for magmatic and hydrothermal processes in carbonatites from the Kaiserstuhl volcanic complex ( SW Germany).Chemical Geology, Vol. 498, pp. 1-16.Europe, Germanycarbonatite

Abstract: Pyrochlore from the Kaiserstuhl volcanic complex (SW Germany) shows textural and compositional differences between various coarse-grained calcite-carbonatite bodies (Badberg, Degenmatt, Haselschacher Buck, Orberg) and extrusive carbonatites (Henkenberg, Kirchberg). Oscillatory-zoned F-rich pyrochlore with up to 69?wt% Nb2O5 is common in all coarse-grained calcite-carbonatite bodies and probably formed during magmatic conditions. However, only in some of the samples from the Badberg, partly resorbed U- and Ta-enriched pyrochlore cores with up to 22?wt% UO2 and 9?wt% Ta2O5 have been identified, which are interpreted as being inherited from underlying nosean syenites. Pyrochlore data from a drill core penetrating the Badberg indicate increasing contents of REE, U, and Ta with depth, while Nb, F and Na contents decrease. This may reflect the combined effects of fractional crystallization and assimilation (AFC) or indicates a multi-stage emplacement of the carbonatitic magma. Patchy-zoned ceriopyrochlore and REE- and Th-enriched pyrochlore with up to 19?wt% total REE2O3 and 6.5?wt% ThO2 is largely restricted to samples from the Orberg and probably formed during hydrothermal conditions. This can be related to the relatively evolved character of the Orberg carbonatites, based on their relatively high whole-rock Nb/Ta and Zr/Hf mass ratios. This study demonstrates that the textural and compositional variation of pyrochlore in carbonatites is a powerful tool to distinguish magmatic, hydrothermal and weathering processes in carbonatitic systems.
DS201812-2810
2019
Marks, M.A.W.Giebel, R.J., Marks, M.A.W., Gauert, C.D.K., Markl, G.A model for the formation of carbonatite-phoscorite assemblages based on the compositional variations of mica and apatite from the Palabora carbonatite complex, South Africa.Lithos, Vol. 324-325, pp. 89-104.Africa, South Africadeposit - Palabora

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

Abstract: A detailed electron microprobe study has been carried out on the compositional variations of mica and apatite from carbonatites, phoscorites and associated pyroxenites (and fenites) of the Loolekop deposit, Palabora Carbonatite Complex (South Africa). Mica in pyroxenites and fenites is Mg-rich biotite, whilst micas in carbonatites and phoscorites are compositionally diverse including phlogopite, Ba-rich phlogopite (up to 30% kinoshitalite component), IVAl-rich phlogopite (up to 30% eastonite component) and tetraferriphlogopite. The various types of phlogopites are interpreted as orthomagmatic phases, whereas tetraferriphlogopite precipitation was a late-magmatic to hydrothermal process that additionally introduced REE into the system. Orthomagmatic apatite is generally REE- and Sr-poor fluorapatite and does not show large compositional differences between rock types. Apatite associated with the late-stage tetraferriphlogopite mineralization reaches higher levels of REE (up to 4.9?wt%), Si (up to 1.5?wt% SiO2), Sr (up to 2.6?wt% SrO) and Na (up to 1.0?wt% Na2O). The compositional variation of micas and apatites, which is affiliated with distinct rock types, reflects the multi-stage evolution of the Loolekop deposit and provides detailed insight into the relationships of the carbonatite-phoscorite assemblage. The obtained data support the separation of phoscorite and carbonatite by immiscibility from a common parental magma, which may happen due to a decrease of temperature and/or pressure during the ascent of the magma. This results in a density contrast between the carbonatitic and phoscoritic components that will lead to descending phoscorite accumulations at the outer zones of the magma channel and a jet-like ascent (further promoted by its extremely low viscosity) of the carbonatite magma. The genetic model deduced here explains the peculiar association of carbonatites, phoscorites and silicate rocks in many alkaline complexes worldwide.
DS201903-0498
2019
Marks, M.A.W.Banks, G.J., Walter, B.F., Marks, M.A.W., Siegfried, P.R.A workflow to define, map and name a carbonatite-alkaline igneous-associated REE-HFSE mineral system: a case study from SW Germany.MDPI, Vol. 9, 97, 28p. PdfGlobalREE

Abstract: Security of supply of “hi-tech” raw materials (including the rare earth elements (REE) and some high-field-strength elements (HFSEs)) is a concern for the European Union. Exploration and research projects mostly focus on deposit- to outcrop-scale description of carbonatite- and alkaline igneous-associated REE-HFSE mineralization. The REE-HFSE mineral system concept and approach are at a nascent stage, so developed further here. However, before applying the mineral system approach to a chosen REE-HFSE metallogenic province its mineral system extent first needs defining and mapping. This shifts a mineral system project’s foundation from the mineral system concept to a province’s mineral system extent. The mapped extent is required to investigate systematically the pathways and potential trap locations along which the REE-HFSE mass may be distributed. A workflow is presented to standardize the 4-D definition of a REE-HFSE mineral system at province-scale: (a) Identify and hierarchically organize a mineral system’s genetically related sub-divisions and deposits, (b) map its known and possible maximum extents, (c) name it, (d) discern its size (known mineral endowment), and (e) assess the favorability of the critical components to prioritize further investigations. The workflow is designed to generate process-based perspective and improve predictive targeting effectiveness along under-evaluated plays of any mineral system, for the future risking, comparing and ranking of REE-HFSE provinces and plays.
DS201909-2024
2019
Marks, M.A.W.Braunger, S., Marks, M.A.W., Wenzel, T., Chmyz, L., Azzone, R.G., Markl, G.Carbonatite-alkaline silica rock complexes reflect highly oxidized conditions in their Upper Mantle source.Goldschmidt2019, 1p. AbstractMantlecarbonatite

Abstract: Alkaline complexes consist of variable mantle-derived silicate rocks, ranging from primitive alkali basalts, melilitites, nephelinites and basanites towards tephrites and more evolved phonolites, respectively their plutonic equivalents. This lithological variance is also expressed by a wide range of redox conditions that vary by several log units around the synthetic fayalite-magnetite-quartz (FMQ) buffer. However, only some of these complexes are characterized by the occurrence of carbonatites which must be related to specific formation conditions. Based on textural, mineralogical and geochemical observations, we calculated the redox conditions of carbonatites and associated silicate rocks for seven alkaline complexes (Kaiserstuhl, Sokli, Kovdor, Palabora, Magnet Cove, Oka, Jacupiranga) which are considered to represent typical carbonatite-alkaline silicate rock associations. In combination with a comprehensive literature review, we demonstrate that carbonatite-bearing alkaline complexes formed under highly oxidized conditions and hence, belong to the most oxidized alkaline rocks at all. This is consistent with the prerequisite of a carbonated mantle as the source region for carbonatite complexes, which requires redox conditions distinctively above that for mean lithospheric or asthenospheric mantle. Carbonatitemetasomatized peridotites also show high redox conditions and might not only reflect an interaction between peridotite and carbonatitic melts/fluids, but at least partly represent the carbonated mantle source for crustally emplaced carbonatite complexes. We therefore suggest that the oxidation state of carbonatites and associated silicate rocks provides direct information about an extraordinary oxidized parental mantle source.
DS201909-2041
2019
Marks, M.A.W.Giebel, R.J., Marks, M.A.W., Gauert, C.D.K., Markl, G.A model for the formation of carbonatite-phoscorite assemblages.Goldschmidt2019, 1p. AbstractGlobalcarbonatite

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

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

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

Abstract: Studies on fluid inclusions in carbonatitic rocks are essential to understand the physicochemical processes involved in carbonatite-related hydrothermal ore mineralization. Although little is known about the composition of carbonatite-derived fluids. We investigated fluid inclusions in the Kaiserstuhl carbonatites, SW Germany [1,2] and identified four different types typically known from carbonatitic systems worldwide [3]: (I): Vapor-poor H2O-NaCl fluids with <50 wt.% salinity. (II): Vapor-rich H2O-NaCl-CO2 fluids with <5 wt.% salinity. (III): Multi-component fluids with high salinity and CO2. (IV): Multi-component fluids with high salinity, no CO2. Homogenization temperatures (156 to 530°C) of all fluid types generally show a wide range [this study, 2]. Primary type I fluid inclusions occur in early magmatic olivine/monticellite, as well as paragenetically later apatites and calcites [2]. This indicates a ubiquitous existence of a saline brine, which does not reach saturation with respect to halite, during early to late crystallization stages. Liquidus surface modelling based quantifications for fluid type III suggest that carbonatite melts predomonantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (type III or IV, respectively). Such fluid inclusions, with type III (CO2-free) on one side and type IV (and II, both CO2-rich) on the other side, may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, is probably triggered by a rapid pressure release during “pneumatic hammer-like,” discontinuous melt ascent.
DS202002-0168
2020
Marks, M.A.W.Braunger, S., Marks, M.A.W., Wenzel, T., Chmyz, L., Azzone, R.G., Markl, G.Do carbonatites and alkaline rocks reflect variable redox conditions in their upper mantle source? ( metasomatism)Earth and Planetary Science Letters, Vol. 533, 11p. PdfMantlecarbonatite

Abstract: A detailed investigation on seven carbonatites and associated alkaline rock complexes (Kaiserstuhl, Sokli, Kovdor, Palabora, Oka, Magnet Cove, Jacupiranga), together with a world-wide comparison between carbonatites, alkaline silicate rocks and mantle xenoliths, implies peculiar redox conditions for carbonatite-bearing alkaline complexes: Carbonatites and associated alkaline rocks in continental settings crystallize from relatively oxidized magmas, on average 1.4 log units () and 1.3 log units () above the synthetic fayalite-magnetite-quartz (FMQ) buffer. In contrast, alkaline rocks in continental settings that lack associated carbonatites reveal rather reduced conditions (mean ; ). The calculated redox conditions for carbonatites and associated silicate rocks demonstrate that these crystallize from relatively oxidized mantle-derived melts compared to the general range found for alkaline rocks in continental settings.
DS202006-0955
2020
Marks, M.A.W.Walter, B.F., Steele-MacInnis, M., Giebel, R.J., Marks, M.A.W., Markl, G.Complex carbonatite-sulfate brines in fluid inclusions from carbonatites: estimating compositions in the system H2O-Na-K-CO3-SO4-Cl. KaiserstuhlGeochimica et Cosmochimica Acta, Vol. 277, pp. 224-242. pdfEurope, Germanycarbonatite

Abstract: Studies of fluid inclusions in carbonatitic rocks are essential for understanding physicochemical processes involved in carbonatite-related hydrothermal ore mineralization and fenitization. However, the composition of many carbonatite-derived fluids is challenging to quantify, which hampers their detailed interpretation. Here, we present a systematic study of microthermometry of fluid inclusions found in carbonatites from the Kaiserstuhl (SW Germany), and a simple numerical model to estimate the compositions of such fluids, which are typical of numerous carbonatites worldwide. Four types of fluid inclusions have been identified in the Kaiserstuhl carbonatites: (I) vapor-poor H2O-NaCl fluids with <50?wt.% salinity; (II) vapor-rich H2O-NaCl-CO2 fluids with <5?wt.% salinity; (III) multi-component fluids with high salinity and high CO2 contents; and (IV) multi-component fluids with high salinity but little to no CO2. At present, it is only possible to quantify fluid compositions for types I and II. For the complex types III and IV, we conducted predictive modeling of the liquidus surface based on the Margules equations. The results suggest that carbonatite melts predominantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (types III or IV). Such fluid inclusions may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, was probably triggered by a rapid pressure release during melt ascent. The present model enables quantification of fluid compositions associated with carbonatitic magmatism.
DS202007-1145
2020
Marks, M.A.W.Hecker, J.G., Marks, M.A.W., Wenzel, T., Markl, G.Halogens in amphibole and mica from mantle xenoliths: implications for the halogen distribution and halogen budget of the metasomatized continental lithosphere.American Mineralogist, Vol. 105, pp. 781-794.Mantlemetasomatism

Abstract: This study reports halogen contents (F and Cl) of amphibole and phlogopite derived from mantle xenoliths and one peridotite massif, for amphibole and phlogopite megacrysts and ultramafic magmatic cumulates (hornblendites) found in alkaline volcanic rocks from 12 localities in Europe and Africa. Amphibole and phlogopite contain more F than Cl with F/Cl ratios reaching about 160 in phlogopites and 50 in amphiboles. Phlogopites are higher in F (median of 3400 µg/g) than amphibole (median of 1000 µg/g), while median Cl contents are higher in amphibole (290 µg/g) compared to phlogopite (180 µg/g). The Cl contents and the F/Cl ratios in amphibole and phlogopite from mantle xenoliths exhibit large differences between samples of the same region, recording very large variations of halogen contents in the continental lithosphere. We suggest that the halogen content in such samples largely depends on the initial composition of percolating melts and fluids in the continental lithosphere. During reaction of these agents with peridotitic wall-rocks, Cl is preferentially retained in the fluid as it is much more incompatible compared to water and F. This desiccation effect continuously increases salinity (Cl content) and decreases the F/Cl ratio in the agent with time, causing variable Cl contents and F/Cl ratios in amphibole and phlogopite at a specific locality. Subsequent partial melting processes may then sequester and re-distribute, especially Cl among amphibole, phlogopite and melts/fluids as a result of its strong incompatibility, whereas F is much less affected as it behaves slightly compatible. The impact of even small amounts of amphibole and mica on the total halogen budget in the continental lithosphere is significant and both minerals can effectively contribute to the high halogen contents typical of alkaline melts.
DS202007-1184
2020
Marks, M.A.W.Walter, B.F., Steele-MacInnis, M., Gielbel, R.J., Marks, M.A.W., Markl, G.Complex carbonatite-sulfate brines in fluid inclusions from carbonatites: estimating compositions in the system H2O-Na-K-CO3-SO4-ClGeochimica et Cosmochimica Acta, Vol. 277, pp. 224-242. pdfEurope, Germanydeposit - Kaiserstuhl

Abstract: Studies of fluid inclusions in carbonatitic rocks are essential for understanding physicochemical processes involved in carbonatite-related hydrothermal ore mineralization and fenitization. However, the composition of many carbonatite-derived fluids is challenging to quantify, which hampers their detailed interpretation. Here, we present a systematic study of microthermometry of fluid inclusions found in carbonatites from the Kaiserstuhl (SW Germany), and a simple numerical model to estimate the compositions of such fluids, which are typical of numerous carbonatites worldwide. Four types of fluid inclusions have been identified in the Kaiserstuhl carbonatites: (I) vapor-poor H2O-NaCl fluids with <50?wt.% salinity; (II) vapor-rich H2O-NaCl-CO2 fluids with <5?wt.% salinity; (III) multi-component fluids with high salinity and high CO2 contents; and (IV) multi-component fluids with high salinity but little to no CO2. At present, it is only possible to quantify fluid compositions for types I and II. For the complex types III and IV, we conducted predictive modeling of the liquidus surface based on the Margules equations. The results suggest that carbonatite melts predominantly exsolve Na-K-sulfate-carbonate/bicarbonate-chloride brines (types III or IV). Such fluid inclusions may represent immiscible fluids that were trapped after segregation by boiling from a parental highly saline brine (type I). Fluid boiling, in turn, was probably triggered by a rapid pressure release during melt ascent. The present model enables quantification of fluid compositions associated with carbonatitic magmatism.
DS202102-0198
2021
Marks, M.A.W.Hoare, B.C., Tomlinson, E.L., Barnes, J.D., Tappe, S., Marks, M.A.W., Epp, T., Caulfield, J., Riegler, T.Tracking halogen recycling and volatile loss in kimberlite magmatism from Greenland: evidence from combined F-Cl-Br and Delta 37Cl systematics.Lithos, doi;101016/j. lithos.2021.105976 78p. PdfEurope, Greenlandhalogen
DS1996-0887
1996
Marks, P.Marks, P.The mystery of the appearing diamondNew Scientist, March 23, p. 22.GlobalDiamond genesis
DS200412-0446
2004
Markwich, A.Dessai, A.G., Markwich, A., Vaselli, O., Downes, H.Granulite and pyroxenite xenoliths from the Deccan Trap: insights into the nature and composition of the lower lithosphere beneaLithos, Vol. 78, 3, Nov. pp. 263-290.IndiaDharwar Craton, crust-mantle transition
DS2000-0617
2000
Markwick, A.J.W.Markwick, A.J.W., Downes, H.Lower crustal granulite xenoliths from the Arkangelsk kimberlite pipes, petrological, geochemical, geophysicsLithos, Vol. 51, No. 1-2, pp. 135-Russia, Kola Peninsula, ArkangelskXenoliths
DS201902-0295
2019
Markwick, P.J.Markwick, P.J.Palaeogeography in exploration.Geological Magazine, Vol. 156, 2, pp. 366-407.Globalpaleogeography

Abstract: Palaeogeography is the representation of the past surface of the Earth. It provides the spatial context for investigating how the Earth evolves through time, how complex processes interact and the juxtaposition of spatial information. In hydrocarbon exploration, palaeogeographies have been used to map and investigate the juxtaposition, distribution and quality of play elements (source, reservoir, seal and trap), as boundary conditions for source-to-sink analysis, climate modelling and lithofacies retrodiction, but most commonly as the backdrop for presentations and montages. This paper demonstrates how palaeogeography has been and can be used within an exploration workflow to help mitigate exploration risk. A comprehensive workflow for building palaeogeographies is described which is designed to provide a standard approach that can be applied to a range of tasks in exploration and academia. This is drawn from an analysis of the history of palaeogeography and how it has been applied to exploration in the past and why. Map applications, resolution and content depend on where in the exploration and production (E&P) cycle the map is used. This is illustrated here through three case studies, from the strategic decisions of global new ventures exploration to the more detailed basin and petroleum analyses of regional asset teams evaluating basins and plays. Through this, the paper also addresses three commonly asked questions: (1) How can I use palaeogeography in my workflow? (2) How reliable are the maps? (3) How do I build a palaeogeography?
DS1997-0736
1997
Markwick, S.Markwick, S.Changing nature of political risk.. brief overviewMining Engineering, Vol. 49. No. 8, August p. 10-11, 101GlobalEconomics, country risk, Political risk
DS201510-1784
2015
Markwitz, V.Markwitz, V., Hein, K.A.A., Miller, J.Compilation of West African mineral deposits: spatial distribution and mineral endowment. ( mentions diamonds)Precambrian Research, in press available, 21p.Africa, Mali, Mauritania, Senegal, Burkina Faso, Ghana, Ivory CoastMetallogeny

Abstract: The West African Craton is highly endowed in minerals, and their spatial and temporal distribution varies from single to multi-phase mineralization events. They are broadly related to three major tectono-metallogenic elements and formed during distinct mineral epochs: (1) In both Archean Shields (Kénéma-Man and Reguibat) and Paleoproterozoic domains (Baoulé-Mossi, Eglab). These are characterized by giant iron ore deposits that formed between ca. 2.5-2.3 Ga, nearly all gold, porphyry copper, lead-zinc and sedimentary manganese ore that developed between 2.2 and 2.1 Ga, and primary diamonds that formed between two intervals at ca. 2.2-2.0 Ga and in the Mesozoic. (2) Across Pan-African and Variscan belts. These are distinguished by major Precambrian IOCG's, copper-gold that formed at ca. 2.1 Ga and approximately 680 Ma, and Neoproterozoic sedimentary iron ore and phosphate deposits. (3) Within intracratonic and coastal basins. These include the development of Cenozoic lateritic bauxites over Mesozoic dolerites, Tertiary/Quaternary mineral sands deposits, oolitic iron ore and sedimentary phosphate deposits. Geological, spatial and temporal correlations using the multi-commodity West African Mineral Deposit Database highlight that gold and non-gold commodities formed in multiple phases. This commenced in the Liberian Orogeny (2.9-2.8 Ga) with the enrichment of iron ore, nickel sulphides, diamonds and gold in the earth's crust. The pre-Eburnean or Tangaean-EoEburnean-Eburnean I Event yielded gold, and the major Eburnean Orogeny yielded gold, iron ore, manganese, diamonds, magmatic nickel sulphides, copper-gold, lead-zinc, and REE minerals. Throughout the Pan-African event sedimentary manganese deposits, lead-zinc, REE minerals, sedimentary phosphates, and again gold were formed. Primary diamonds and magmatic nickel sulphides are related to the break-up of Gondwana, followed by an intense lateritic weathering period that formed bauxite deposits along the craton margin.
DS201512-1940
2015
Markwitz, V.Markwitz, V., Hein, K.A.A., Jessell, M.W., Miller, J.Metallogenic portfolio of the West African Craton. ( mentions kimberlites)Ore Geology Reviews, Oct 28 10.024Africa, West AfricaReguibat shield, Kenema-Man shield

Abstract: The West African Craton hosts major resources of gold, iron ore, aluminium ore, diamonds, phosphates and manganese. This portfolio of ore deposits is linked to the formation of Archean -Paleoproterozoic greenstone belts, Jurassic rifting and extended periods of Mesozoic to Cenozoic weathering and erosion. We give a brief overview of the temporal and spatial distribution patterns of West African ore deposits with emphasis on the main commodity types. The oldest ore forming processes generated major resources in iron ore and gold in the Kénéma -Man and Reguibat Shields during the Neo-Archean. The majority of gold, porphyry copper, lead -zinc and sedimentary manganese deposits formed during the Paleoproterozoic, dominantly within the Baoulé-Mossi domain. At the same time diamond-bearing kimberlites developed in Ghana. Another distinct diamond event has been recognized in the Mesozoic of the Kénéma -Man shield. Isolated occurrences of IOCG's as well as copper -gold and gold formed in Pan-African/Variscan belts. During the Neoproterozoic, the majority of mineralization consists of sedimentary iron ore and phosphate deposits located within intracratonic basins. During the Phanerozoic aluminium ore, phosphates and mineral sands concentrated along the margins of the coastal and intracratonic basins.
DS201604-0618
2016
Markwitz, V.Markwitz, V., Hein, K.A.A., Jessell, M.W., Miller, J.Metallogenic portfolio of the West African craton. Mentions diamonds in S.L.Ore Geology Reviews, in press available 6p.Africa, Sierra LeoneMetallogeny
DS201608-1422
2016
Markwitz, V.Markwitz, V., Hein, K.A.A., Jessell, M.W., Miller, J.Metallogenic portfolio of the West Africa craton. Mentions diamonds in Ghana, Mali and GuineaOre Geology Reviews, Vol. 78, pp. 558-563.Africa, Ghana, Mali, GuineaAlluvials
DS1992-0684
1992
Marlatt, G.G.Hausel, H.D., Marlatt, G.G., Nielson, E.L., Gregory, R.H.Preliminary study of metals and precious stones along the Union Pacific right of way, southern WyomingWyoming Geological Survey Open File Report, No. 92-5, 79pWyomingDiamonds mentioned
DS1860-0562
1887
Marloth, R.Marloth, R.On the Origin of the Diamond Mines of South AfricaPhil. Soc. Sth. Afr. Transactions, Vol. 4, No. 1, PP. 62-65.Africa, South Africa, Griqualand West, TransvaalDiamond Genesis
DS1910-0073
1910
Marloth, R.Marloth, R.Notes on the Origin of Diamonds of German Southwest AfricaSouth African Journal of Science, Vol. 6, PP. 112-113. ALSO: The Mining Journal, Vol. 87, 1909 PP. 3Southwest Africa, NamibiaGeology, Diamond Genesis, Marine Diamond Placers
DS1970-0556
1972
Marlowe, J.Marlowe, J.Cecil Rhodes. the Anatomy of EmpireMason and Lipscomb, N.Y, 304pSouth AfricaBiography
DS1960-0069
1960
Marlowe, J.I.Marlowe, J.I.Diatremes and a Ring Intrusion on the San Carlos Indian Reservation.Arizona Geological Society Digest., Vol. 3, PP. 150-154.United States, Arizona, Colorado Plateau, Rocky MountainsDiatreme
DS1997-0737
1997
Marmo, J.Marmo, J., Vilpas, L., Chernet, T., Nenonen. K.Study of the kimberlitic indicator minerals in Quaternary samples, eastern and northern Finland.Papunen: 4th. Biennial SGA Meeting, pp. 775-777.FinlandDiamond exploration, Geomorphology, till, esker sampling, geochemistry
DS1999-0129
1999
Marmo, J.Chernet, T., Marmo, J., Nissinen, A.Significantly improved recovery of slightly heavy minerals from Quaternary samples using GTK Modified ..Minerals Eng., Vol. 12, No. 12, Dec. pp. 1521-6.FinlandMineral processing - recovery, diamonds, gravity, 3Knelson preconcentrator
DS2002-0932
2002
Marmo, J.S.Lehtonen, M.L., Marmo, J.S.Exploring for kimberlites in glaciated terrains using chromite in Quaternary till - a regional case study from northern Finland.Journal of Geochemical Exploration, Vol. 76, 3, pp. 155-74.FinlandGeochemistry - chomites
DS2003-0790
2003
Marmo, J.S.Lehtonen, M.L., Marmo, J.S.Glacial dispersion study of kimberlitic material in Quaternary till from the Lahtojoki8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractFinlandDeposit - Lahtojoki
DS200412-1110
2003
Marmo, J.S.Lehtonen, M.L., Marmo, J.S.Glacial dispersion study of kimberlitic material in Quaternary till from the Lahtojoki pipe, eastern Finland.8 IKC Program, Session 8, POSTER abstractEurope, FinlandDiamond exploration Deposit - Lahtojoki
DS200512-0616
2005
Marmo, J.S.Lehtonen, M.L., Marmo, J.S., Nissinen, A.J., Johanson, B.S., Pakkanen, L.K.Glacial dispersal studies using indicator minerals and till geochemistry around two eastern FIn land kimberlites.Journal of Geochemical Exploration, Vol. 87, 1, Oct. pp. 19-43.Europe, Finland, FennoscandiaKaavi-Kuopio, Kuhmo, geochemistry, Pipe 7, Karelian
DS1950-0438
1958
Marmo, V.Wilson, N.W., Marmo, V.Geology, Geomorphology and Mineral Occurrences of the Sula Mountains Schist Belt, Sierra Leone.Geological Survey SIERRA LEONE Bulletin., No. 1, 103P.Sierra Leone, West AfricaGeology, Diamonds
DS1960-0274
1962
Marmo, V.Marmo, V.Geology and Mineral Resources of the Kangari Hills Schist Belt.Geological Survey SIERRA LEONE Bulletin., No. 2, 117P.Sierra Leone, West AfricaGeology, Kimberlite, Diamond
DS1990-0988
1990
Marocco, R.Marocco, R., Noblet, C.Sedimentation, tectonism and volcanism relationships in two Andean basinsof southern PeruGeologische Rundschau, Vol. 79, No. 1, pp. 111-120Peruvolcanism, Tectonics
DS1996-0087
1996
Marocco, R.Barragan, R., Baudino, R., Marocco, R.Geodynamic evolution of the Neogene intermontane Chota Basin, northern Andes of EcuadorJournal of South American Earth Sciences, Vol. 9, No. 5/6, pp. 309-320EcuadorTectonics, Chota Basin
DS1996-1040
1996
Marocco, R.Noblet, C., Lavenu, A., Marocco, R.Concept of continuum as opposed to periodic tectonism in the AndesTectonophysics, Vol. 255, No. 1-2, April 20, pp. 65-78Andes, PeruTectonics
DS2003-1412
2003
Marone, F.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantleScience, No. 5625, June 6, p. 1556-57.MantleWater
DS200412-1227
2004
Marone, F.Marone, F., Van der Lee, S., Giardini, D.Three dimensional upper mantle S velocity model for the Eurasia Africa plate boundary region.Geophysical Journal International, Vol. 158, 1, pp.109-130.Africa, EuropeTectonics, geophysics - seismics
DS200412-1228
2004
Marone, F.Marone, F., Van der Meijde, M., Van der Lee, S., Giadini, D.Joint inversion of local, regional and teleseismic dat a for crustal thickness in the Eurasia Africa plate boundary region.Geophysical Journal International, Vol. 154, 2, pp. 499-514.Europe, AsiaGeophysics - seismics, boundary
DS200412-2039
2003
Marone, F.Van der Meijde, M., Marone, F., Giardini, D., Van Der Lee, S.Seismic evidence for water deep in Earth's upper mantle.Science, No. 5625, June 6, p. 1556-57.MantleWater
DS200712-0682
2007
Marone, F.Marone, F., Romanowicz, B.The depth distribution of azimuthal anisotropy in the continental upper mantle.Nature, Vol. 447, 7141, pp. 198-201.MantleGeophysics - seismics
DS200712-0683
2007
Marone, F.Marone, F., Romanowicz, B.Non-linear crustal corrections in high resolution regeional waveform seismic tomography.Geophysical Journal International, Vol. 170, 1, July pp. 460-467.MantleGeophysics - seismics
DS200712-0684
2007
Marone, F.Marone, F., Romanowicz, B.Non-linear crustal corrections in high resolution regeional waveform seismic tomography.Geophysical Journal International, Vol. 170, 1, July pp. 460-467.MantleGeophysics - seismics
DS201608-1428
2016
Marone, F.Nimis, P., Alvaro, M., Nestola, F., Angel, R.J., Marquardt, K., Rustioni, G., Harris, J.W., Marone, F.First evidence of hydrous silicic fluid films around solid inclusions in gem-qualty diamonds.Lithos, Vol. 260, pp. 384-389.Russia, Africa, South AfricaDeposit - Udachnaya, Premier

Abstract: Diamonds form from fluids or melts circulating at depth in the Earth's mantle. Analysis of these fluids is possible if they remain entrapped in the diamond during its growth, but this is rarely observed in gem-quality stones. We provide the first evidence that typical mineral inclusions in gem-quality diamonds from the Siberian and Kaapvaal cratons are surrounded by a thin film of hydrous silicic fluid of maximum thickness 1.5 µm. The fluid contains Si2O(OH)6, Si(OH)4, and molecular H2O and was identified using confocal micro-Raman spectroscopy and synchrotron-based X-ray tomographic microscopy. As the solid mineral inclusions have both peridotitic and eclogitic affinities and occur in two cratonic regions, our results demonstrate the strong connection between water-rich fluids and the growth of gem-quality lithospheric diamonds. The presence of the fluid films should be taken into account for a proper evaluation of H2O contents in the mantle based on H2O contents in solid inclusions and for a robust assessment of diamond formation pressures based on the residual pressures of the inclusions.
DS201809-2043
2018
Marone, F.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.
DS201904-0714
2019
Marone, F.Anzolini, C., Nestola, F., Mazzucchelli, M.L., Alvaro, M., Nimis, P., Gianese, A., Morganti, S., Marone, F., Campione, M., Hutchison, M.T., Harris, J.W.Depth of diamond formation obtained from single periclase inclusions. SDD ( Super Deep Diamonds)Geology , Vol. 47, 3, pp. 219-222.South America, Brazil, Guyanadiamond genesis

Abstract: Super-deep diamonds (SDDs) are those that form at depths between ~300 and ~1000 km in Earth’s mantle. They compose only 1% of the entire diamond population but play a pivotal role in geology, as they represent the deepest direct samples from the interior of our planet. Ferropericlase, (Mg,Fe)O, is the most abundant mineral found as inclusions in SDDs and, when associated with low-Ni enstatite, which is interpreted as retrogressed bridgmanite, is considered proof of a lower-mantle origin. As this mineral association in diamond is very rare, the depth of formation of most ferropericlase inclusions remains uncertain. Here we report geobarometric estimates based on both elasticity and elastoplasticity theories for two ferropericlase inclusions, not associated with enstatite, from a single Brazilian diamond. We obtained a minimum depth of entrapment of 15.7 (±2.5) GPa at 1830 (±45) K (~450 [±70] km depth), placing the origin of the diamond-inclusion pairs at least near the upper mantle-transition zone boundary and confirming their super-deep origin. Our analytical approach can be applied to any type of mineral inclusion in diamond and is expected to allow better insights into the depth distribution and origin of SDDs.
DS201905-1063
2019
Marone, F.Nimis, P., Angel, R.J., Alvaro, M., Nestola, F., Harris, J.W., Casati, N., Marone, F.Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?Contributions to Mineralogy and Petrology, Vol. 174, p. 29- 13p.Russia, Siberiadeposit - Udachnaya

Abstract: We have studied by X-ray diffractometry the crystallographic orientation relationships (CORs) between magnesiochromite (mchr) inclusions and their diamond hosts in gem-quality stones from the mines Udachnaya (Siberian Russia), Damtshaa (Botswana) and Panda (Canada); in total 36 inclusions in 23 diamonds. In nearly half of the cases (n?=?17), [111]mchr is parallel within error to [111]diamond, but the angular misorientation for other crystallographic directions is generally significant. This relationship can be described as a case of rotational statistical COR, in which inclusion and host share a single axis (1 df). The remaining mchr-diamond pairs (n?=?19) have a random COR (2 df). The presence of a rotational statistical COR indicates that the inclusions have physically interacted with the diamond before their final incorporation. Of all possible physical processes that may have influenced mchr orientation, those driven by surface interactions are not considered likely because of the presence of fluid films around the inclusions. Mechanical interaction between euhedral crystals in a fluid-rich environment is therefore proposed as the most likely mechanism to produce the observed rotational COR. In this scenario, neither a rotational nor a random COR can provide information on the relative timing of growth of mchr and diamond. Some multiple, iso-oriented inclusions within single diamonds, however, indicate that mchr was partially dissolved during diamond growth, suggesting a protogenetic origin of these inclusions.
DS201909-2076
2019
Marone, F.Piazzi, M., Morana, M., Coisson, M., Marone, F., Campione, M., Bindi, L., Jones, A.P., Ferrara, E., Alvaro, M.Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds.Diamonds and Related Materials, in press available 36p. PdfAfrica, Ghanadeposit - Akwatia

Abstract: Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possibility is related to their capability to carry a remanent magnetization dependent on their magnetic history. However, comprehensive experimental studies on magnetic inclusions in diamonds have been rarely reported so far. Here we exploit X-ray diffraction, Synchrotron-based X-ray Tomographic Microscopy and Alternating Field Magnetometry to determine the crystallographic, morphological and magnetic properties of ferrimagnetic Fe-oxides entrapped in diamonds coming from Akwatia (Ghana). We exploit the methodology to estimate the natural remanence of the inclusions, associated to the Earth's magnetic field they experienced, and to get insights on the relative time of formation between host and inclusion systems. Furthermore, from the hysteresis loops and First Order Reversal Curves we determine qualitatively the anisotropy, size and domain state configuration of the magnetic grains constituting the inclusions.
DS201910-2292
2019
Marone, F.Piazzi, M., Morana, M., Coisson, M., Marone, F., Campione, M., Bindi, L., Jones, A.P., Ferrara, E., Alvaro, M.Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds. Akwatiaresearchgate.net, June 18, 333866141 12p. PdfAfrica, Ghanadeposit - Akwatia

Abstract: Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possibility is related to their capability to carry a remanent magnetization dependent on their magnetic history. However, comprehensive experimental studies on magnetic inclusions in diamonds have been rarely reported so far. Here we exploit X-ray diffraction, Synchrotron-based X-ray Tomographic Microscopy and Alternating Field Magnetometry to determine the crystallographic, morphological and magnetic properties of ferrimagnetic Fe-oxides entrapped in diamonds coming from Akwatia (Ghana). We exploit the methodology to estimate the natural remanence of the inclusions, associated to the Earth's magnetic field they experienced, and to get insights on the relative time of formation between host and inclusion systems. Furthermore, from the hysteresis loops and First Order Reversal Curves we determine qualitatively the anisotropy, size and domain state configuration of the magnetic grains constituting the inclusions.
DS201912-2768
2019
Marone, F.Alvaro, M., Mazzucchelli, M.L., Angel, R.J., Murri, M., Campmenosi, N., Scambelluri, M., Nestola, F., Korsakov, A., Tomilenko, A.A., Marone, F., Morana, M.Fossil subduction recorded by quartz from the coesite stability field. GeobarometryGeology, in press, 5p. PdfRussia, Yakutiadeposit - Mir

Abstract: Metamorphic rocks are the records of plate tectonic processes whose reconstruction relies on correct estimates of the pressures and temperatures (P-T) experienced by these rocks through time. Unlike chemical geothermobarometry, elastic geobarometry does not rely on chemical equilibrium between minerals, so it has the potential to provide information on overstepping of reaction boundaries and to identify other examples of non-equilibrium behavior in rocks. Here we introduce a method that exploits the anisotropy in elastic properties of minerals to determine the unique P and T of entrapment from a single inclusion in a mineral host. We apply it to preserved quartz inclusions in garnet from eclogite xenoliths hosted in Yakutian kimberlites (Russia). Our results demonstrate that quartz trapped in garnet can be preserved when the rock reaches the stability field of coesite (the high-pressure and high-temperature polymorph of quartz) at 3 GPa and 850 °C. This supports a metamorphic origin for these xenoliths and sheds light on the mechanisms of craton accretion from a subducted crustal protolith. Furthermore, we show that interpreting P and T conditions reached by a rock from the simple phase identification of key inclusion minerals can be misleading.
DS1984-0323
1984
Marot, A.Gruau, G., Martin, H., Leveque, B., Capdevila, R., Marot, A.Rubidium-strontium and Samarium-neodymium (sm-nd) Geochronology of Lower proterozoic Granite Greenstone Terrains in French Guiana, South America.B.r.g.m., IN PRESSSouth America, French GuianaBlank
DS1984-0482
1984
Marot, A.Marot, A., Capdevila, R., Leveque, B., Gruau, G., Martin, G., Cha.Le Synclinorium du Sud de Guyane Francaise: une Ceinture Deroches Vertes D'age Proterozoic Inferieur.Annual DES SCIENCES DE la TERRE, 10TH. SESSION HELD BORDEAU, South America, GuyanaBlank
DS1998-0943
1998
Marotta, A.M.Marotta, A.M., Fernandez, M., Sabadini, P.Mantle uprooting in collisional settingsTectonophysics, Vol. 296, No. 1-2, pp. 31-46.MantleTectonics, Collision
DS2002-1378
2002
Marotta, A.M.Sabadini, R., Marotta, A.M., De Franco, R., Vermeersen, L.L.A.Style of density stratification in the mantle and true polar wander induced by ice loadingJournal of Geophysical Research, Oct. 29, 10.1029/2001JB000889.MantleGeophysics - seismics
DS200512-1097
2005
Marotta, A.M.Tosi, N., Sabadini, R., Marotta, A.M., Vermeersen, L.L.A.Simultaneous inversion for the Earth's mantle viscosity and ice mass imbalance in Antarctica and Greenland.Journal of Geophysical Research, Vol. 110, B7, B07402 10.1029/2004 JB003236Europe, GreenlandMantle dynamics
DS1991-1529
1991
Marple, R.T.Schweig, E.S.III, Marple, R.T.Bootheel lineament: a possible coseismic fault of the great New MadridearthquakeGeology, Vol. 19, No. 10, October pp. 1025-1028Arkansas, Kentucky, Missouri, TennesseeMidcontinent, Rifting, tectonics
DS1992-1000
1992
Marple, R.T.Marple, R.T., Schweig, E.S. III.Remote sensing of alluvial terrain in a humid, tectonically active setting:the New Madrid seismic zonePhotogrammetric Eng. and Remote Sensing, Vol. 58, No. 2, February pp. 209-219GlobalRemote sensing, Midcontinent tectonics
DS201312-0540
2013
Marquardt, H.Lin, J-F., Speciale, S., Mao, Z., Marquardt, H.Effects of the electronic spin transitions of iron in lower mantle minerals: implications for deep mantle geophysics and geochemistry.Reviews of Geophysics, Vol. 51, 2, pp. 244-275.MantleMineralogy
DS201505-0255
2015
Marquardt, H.Marquardt, H., Miyagi, L.Slab stagnation in the shallow mantle linked to an increase in mantle viscosity.Nature Geoscience, Vol. 8, pp. 311-314.MantleSubduction
DS201809-2003
2018
Marquardt, H.Buchen, J., Marquardt, H., Speziale, S., Kawazoe, T., Ballaran, T.B., Kumosov, A.High pressure single crystal elasticity of wadlsleyite and the seismic signature of water on the shallow transition zone.Earth and Planetary Science Letters, Vol. 498, pp. 77-87.Mantlegeophysics - seismic

Abstract: Earth's transition zone at depths between 410 km and 660 km plays a key role in Earth's deep water cycle since large amounts of hydrogen can be stored in the nominally anhydrous minerals wadsleyite and ringwoodite, . Previous mineral physics experiments on iron-free wadsleyite proposed low seismic velocities as an indicative feature for hydration in the transition zone. Here we report simultaneous sound wave velocity and density measurements on iron-bearing wadsleyite single crystals with 0.24 wt-% . By comparison with earlier studies, we show that pressure suppresses the velocity reduction caused by higher degrees of hydration in iron-bearing wadsleyite, ultimately leading to a velocity cross-over for both P-waves and S-waves. Modeling based on our experimental results shows that wave speed variations within the transition zone as well as velocity jumps at the 410-km seismic discontinuity, both of which have been used in previous work to detect mantle hydration, are poor water sensors. Instead, the impedance contrast across the 410-km seismic discontinuity that is reduced in the presence of water can serve as a more robust indicator for hydrated parts of the transition zone.
DS201809-2083
2018
Marquardt, H.Schulze, K., Marquardt, H., Kawazoe, T., Boallaran, T.B., McCammon, C., Koch-Muller, M., Kurnosov, A., Marquardt, K.Seismically invisable water in Earth's transition zone?Earth and Planetary Science Letters, Vol. 498, pp. 9-16.Mantlewater

Abstract: Ringwoodite, the dominant mineral at depths between 520 km and 660 km, can store up to 2-3 wt.% of water in its crystal structure, making the Earth's transition zone a plausible water reservoir that plays a central role in Earth's deep water cycle. Experiments show that hydration of ringwoodite significantly reduces elastic wave velocities at room pressure, but the effect of pressure remains poorly constrained. Here, a novel experimental setup enables a direct quantification of the effect of hydration on ringwoodite single-crystal elasticity and density at pressures of the Earth's transition zone and high temperatures. Our data show that the hydration-induced reduction of seismic velocities almost vanishes at conditions of the transition zone. Seismic data thus agree with a wide range of water contents in the transition zone.
DS202009-1635
2020
Marquardt, H.Koemets, I., Satta, N., Marquardt, H., Kiseeva, E.S., Kurnosov, A., Stachel, T., Harris, J.W., Dubrovinsky, L.Elastic properties of majorite garnet inclusions in diamonds and the seismic signature of pyroxenites in the Earth's upper mantle.American Mineralogist, Vol. 105, pp. 984-991. pdfMantlediamond inclusions

Abstract: Majoritic garnet has been predicted to be a major component of peridotite and eclogite in Earth's deep upper mantle (>250 km) and transition zone. The investigation of mineral inclusions in diamond confirms this prediction, but there is reported evidence of other majorite-bearing lithologies, intermediate between peridotitic and eclogitic, present in the mantle transition zone. If these lithologies are derived from olivine-free pyroxenites, then at mantle transition zone pressures majorite may form monomineralic or almost monomineralic garnetite layers. Since majoritic garnet is presumably the seismically fastest major phase in the lowermost upper mantle, the existence of such majorite layers might produce a detectable seismic signature. However, a test of this hypothesis is hampered by the absence of sound wave velocity measurements of majoritic garnets with relevant chemical compositions, since previous measurements have been mostly limited to synthetic majorite samples with relatively simple compositions. In an attempt to evaluate the seismic signature of a pyroxenitic garnet layer, we measured the sound wave velocities of three natural majoritic garnet inclusions in diamond by Brillouin spectroscopy at ambient conditions. The chosen natural garnets derive from depths between 220 and 470 km and are plausible candidates to have formed at the interface between peridotite and carbonated eclogite. They contain elevated amounts (12-30%) of ferric iron, possibly produced during redox reactions that form diamond from carbonate. Based on our data, we model the velocity and seismic impedance contrasts between a possible pyroxenitic garnet layer and the surrounding peridotitic mantle. For a mineral assemblage that would be stable at a depth of 350 km, the median formation depth of our samples, we found velocities in pyroxenite at ambient conditions to be higher by 1.9(6)% for shear waves and 3.3(5)% for compressional waves compared to peridotite (numbers in parentheses refer to uncertainties in the last given digit), and by 1.3(13)% for shear waves and 2.4(10)% for compressional waves compared to eclogite. As a result of increased density in the pyroxenitic layer, expected seismic impedance contrasts across the interface between the monomineralic majorite layer and the adjacent rocks are about 5-6% at the majorite-eclogite-interface and 10-12% at the majoriteperidotite-boundary. Given a large enough thickness of the garnetite layer, velocity and impedance differences of this magnitude could become seismologically detectable.
DS201608-1428
2016
Marquardt, K.Nimis, P., Alvaro, M., Nestola, F., Angel, R.J., Marquardt, K., Rustioni, G., Harris, J.W., Marone, F.First evidence of hydrous silicic fluid films around solid inclusions in gem-qualty diamonds.Lithos, Vol. 260, pp. 384-389.Russia, Africa, South AfricaDeposit - Udachnaya, Premier

Abstract: Diamonds form from fluids or melts circulating at depth in the Earth's mantle. Analysis of these fluids is possible if they remain entrapped in the diamond during its growth, but this is rarely observed in gem-quality stones. We provide the first evidence that typical mineral inclusions in gem-quality diamonds from the Siberian and Kaapvaal cratons are surrounded by a thin film of hydrous silicic fluid of maximum thickness 1.5 µm. The fluid contains Si2O(OH)6, Si(OH)4, and molecular H2O and was identified using confocal micro-Raman spectroscopy and synchrotron-based X-ray tomographic microscopy. As the solid mineral inclusions have both peridotitic and eclogitic affinities and occur in two cratonic regions, our results demonstrate the strong connection between water-rich fluids and the growth of gem-quality lithospheric diamonds. The presence of the fluid films should be taken into account for a proper evaluation of H2O contents in the mantle based on H2O contents in solid inclusions and for a robust assessment of diamond formation pressures based on the residual pressures of the inclusions.
DS201608-1430
2016
Marquardt, K.Palot, M., Jacobsen, S.D., Townsend, J.P., Nestols, F., Marquardt, K., Harris, J.W., Stachel, T., McCammon, C.A., Pearson, D.G.Evidence for H2O bearing fluids in the lower mantle from diamond inclusion.Lithos, in press available 27p.South America, BrazilSao Luis

Abstract: In this study, we report the first direct evidence for water-bearing fluids in the uppermost lower mantle from natural ferropericlase crystal contained within a diamond from São Luíz, Brazil. The ferropericlase exhibits exsolution of magnesioferrite, which places the origin of this assemblage in the uppermost part of the lower mantle. The presence of brucite-Mg(OH)2 precipitates in the ferropericlase crystal reflects the later-stage quenching of H2O-bearing fluid likely in the transition zone, which has been trapped during the inclusion process in the lower mantle. Dehydration melting may be one of the key processes involved in transporting water across the boundary between the upper and lower mantle.
DS201611-2135
2016
Marquardt, K.Rudloff-Grund, J., Brenker, F.E., Marquardt, K., Howell, D., Schrieber, A., O'Reilly, S.Y., Griffin, W.L., Kaminsky, F.V.Nitrogen nanoinclusions in milky diamonds from Juin a area, Mato Grosso State, Brazil.Lithos, in press available 34p.South America, Brazil, Mato GrossoDeposit - Juina
DS201804-0719
2018
Marquardt, K.Marquardt, K., Faul, U.H.The structure and composition of olivine grain boundaries: 40 years of studies, status and current developments.Physics and Chemistry of Minerals, Vol. 45, 2, pp. 139-172.Mantleolivines

Abstract: Interfaces in rocks, especially grain boundaries in olivine dominated rocks, have been subject to about 40 years of studies. The grain boundary structure to property relation is fundamental to understand the diverging properties of polycrystalline samples compared to those of single crystals. The number of direct structural observations is small, i.e. in range of 100 micrographs, and the number of measurements of properties directly linked to structural observations is even smaller. Bulk aggregate properties, such as seismic attenuation, rheology and electrical conductivity, are sensitive to grain size, and seem to show influences by grain boundary character distributions. In this context we review previous studies on grain boundary structure and composition and plausible relations to bulk properties. The grain boundary geometry is described using five independent parameters; generally, their structural width ranges between 0.4-1.2 nm and the commonly used 1 nm seems a good approximation. This region of enhanced disorder is often enriched in elements that are incompatible in the perfect crystal lattice. The chemical composition of grain boundaries depends on the bulk rock composition. We determined the 5 parameter grain boundary character distribution (GBCD) for polycrystaline Fo90 and studied structure and chemistry at the nm-scale to extend previous measurements. We find that grain boundary planes close to perpendicular to the crystallographic c-direction dominate the grain boundary network. We conclude that linking grain boundary structure in its full geometric parameter space to variations of bulk rock properties is now possible by GBCD determination using EBSD mapping and statistical analyses.
DS201809-2083
2018
Marquardt, K.Schulze, K., Marquardt, H., Kawazoe, T., Boallaran, T.B., McCammon, C., Koch-Muller, M., Kurnosov, A., Marquardt, K.Seismically invisable water in Earth's transition zone?Earth and Planetary Science Letters, Vol. 498, pp. 9-16.Mantlewater

Abstract: Ringwoodite, the dominant mineral at depths between 520 km and 660 km, can store up to 2-3 wt.% of water in its crystal structure, making the Earth's transition zone a plausible water reservoir that plays a central role in Earth's deep water cycle. Experiments show that hydration of ringwoodite significantly reduces elastic wave velocities at room pressure, but the effect of pressure remains poorly constrained. Here, a novel experimental setup enables a direct quantification of the effect of hydration on ringwoodite single-crystal elasticity and density at pressures of the Earth's transition zone and high temperatures. Our data show that the hydration-induced reduction of seismic velocities almost vanishes at conditions of the transition zone. Seismic data thus agree with a wide range of water contents in the transition zone.
DS202009-1606
2020
Marquardt, K.Anzolini, C., Marquardt, K., Stagno, V., Nestola, F.Evidence for complex iron oxides in the deep mantle from FeNi(Cu) inclusions in superdeep diamondsProceedings of the National Academy of Sciences, pnas.org/cgi/doi.10.1073 /pnas.2004269117 7p. PdfMantlediamond inclusions

Abstract: The recent discovery in high-pressure experiments of compounds stable to 24-26 GPa with Fe4O5, Fe5O6, Fe7O9, and Fe9O11 stoichiometry has raised questions about their existence within the Earth’s mantle. Incorporating both ferric and ferrous iron in their structures, these oxides if present within the Earth could also provide insight into diamond-forming processes at depth in the planet. Here we report the discovery of metallic particles, dominantly of FeNi (Fe0.71Ni0.24Cu0.05), in close spatial relation with nearly pure magnetite grains from a so-called superdeep diamond from the Earth’s mantle. The microstructural relation of magnetite within a ferropericlase (Mg0.60Fe0.40)O matrix suggests exsolution of the former. Taking into account the bulk chemistry reconstructed from the FeNi(Cu) alloy, we propose that it formed by decomposition of a complex metal M oxide (M4O5) with a stoichiometry of (Fe3+2.15Fe2+1.59Ni2+0.17Cu+0.04)S = 3.95O5. We further suggest a possible link between this phase and variably oxidized ferropericlase that is commonly trapped in superdeep diamond. The observation of FeNi(Cu) metal in relation to magnetite exsolved from ferropericlase is interpreted as arising from a multistage process that starts from diamond encapsulation of ferropericlase followed by decompression and cooling under oxidized conditions, leading to the formation of complex oxides such as Fe4O5 that subsequently decompose at shallower P-T conditions.
DS2001-1128
2001
Marquart, G.Steinberger, B., Schmeling, H., Marquart, G.Large scale lithospheric stress field and topography induced by global mantle circulation.Earth and Planetary Science Letters, Vol. 186, No. 1, Mar. 15, pp. 75-92.MantleGeophysics, Tectonics, geodynamics
DS2003-1224
2003
Marquart, G.Schmeling, H., Marquart, G., Ruedas, T.Pressure and temperature dependent thermal expansivity and the effect on mantleGeophysical Journal International, No. 154, 1, pp. 224-9.MantleBlank
DS200412-1229
2004
Marquart, G.Marquart, G., Schmeling, H.A dynamic model for the Iceland plume and the north Atlantic based on tomography and gravity data.Geophysical Journal International, Vol. 159, 1, pp. 40-52.Europe, IcelandGeodynamics, tectonics, geophysics - gravity
DS200412-1753
2003
Marquart, G.Schmeling, H., Marquart, G., Ruedas, T.Pressure and temperature dependent thermal expansivity and the effect on mantle convection and surface observables.Geophysical Journal International, No. 154, 1, pp. 224-9.MantleGeothermometry
DS200812-1018
2008
Marquart, G.Schmeling, H., Marquart, G.Crustal accretion and dynamic feedback on mantle melting of a ridge centred plume: the Iceland case.Tectonophysics, Vol. 447, 1-4, pp. 31-52.Europe, IcelandMelting
DS1991-1059
1991
Marquatt, G.Marquatt, G.Finite element modeling of lower crustal flow: a model for crustal thickness variationsJournal of Geophysical Research, Vol. 96, No. B12, November 10, pp. 20, 331-20, 335MantleCrust, Modeling -experimental
DS201712-2725
2017
Marquea, J.C.Rossoni, M.B., Bastos Neto, A.C., Souza, V.S., Marquea, J.C., Dantas, E., Botelho, N.F., Giovannini, A.L., Pereira, V.P.U-Pb zircon geochronological investigation on the Morro dos Seis Lagos carbonatite complex and associated Nb deposit ( Amazonas, Brazil).Journal of South American Earth Sciences, Vol. 80, pp. 1-17.South America, Brazilcarbonatite

Abstract: We present results of U-Pb dating (by MC-ICP-MS) of zircons from samples that cover all of the known lithotypes in the Seis Lagos Carbonatite Complex and associated lateritic mineralization (the Morro dos Seis Lagos Nb deposit). The host rock (gneiss) yielded an age of 1828 ± 09 Ma interpreted as the crystallization time of this unit. The altered feldspar vein in the same gneiss yielded an age of 1839 ± 29 Ma. Carbonatite samples provided 3 groups of ages. The first group comprises inherited zircons with ages compatible with the gneissic host rock: 1819 ± 10 Ma (superior intercept), 1826 ± 5 Ma (concordant age), and 1812 ± 27 Ma (superior intercept), all from the Orosirian. The second and the third group of ages are from the same carbonatite sample: the superior intercept age of 1525 ± 21 Ma (MSWD ¼ 0.77) and the superior intercept age of 1328 ± 58 Ma (MSWD ¼ 1.4). The mineralogical study indicates that the ~1.3 Ga zircons have affinity with carbonatite. It is, however, a tendence rather than a well-defined result. The data allow state that the age of 1328 ± 58 Ma represents the maximum age of the carbonatite. Without the same certainty, we consider that the data suggest that this age may be the carbonatite age, whose emplacement would have been related to the evolution of the K'Mudku belt. The best age obtained in laterite samples (a superior intercept age of 1828 ± 12 Ma) is considered the age of the main source for the inherited zircons related to the gneissic host rock.
DS201912-2821
2019
Marquerno, T.Sanatmaria-Perez, D., Ruiz-Fuertes, J., Pena-Alvarez, M., Chulia-Jordan, R., Marquerno, T., Zimmer, D., Guterrez-Cano, V., Macleod, S., Gregoryanz, E., Popescue, C., Rodriguez-Herandez, P., Munoz, A.Post-tilleyite, a dense calcium silicate carbonate phase.Nature Scientific Reports, Vol. 9, 11p. PdfMantletilleyite

Abstract: Calcium carbonate is a relevant constituent of the Earth’s crust that is transferred into the deep Earth through the subduction process. Its chemical interaction with calcium-rich silicates at high temperatures give rise to the formation of mixed silicate-carbonate minerals, but the structural behavior of these phases under compression is not known. Here we report the existence of a dense polymorph of Ca5(Si2O7)(CO3)2 tilleyite above 8 GPa. We have structurally characterized the two phases at high pressures and temperatures, determined their equations of state and analyzed the evolution of the polyhedral units under compression. This has been possible thanks to the agreement between our powder and single-crystal XRD experiments, Raman spectroscopy measurements and ab-initio simulations. The presence of multiple cation sites, with variable volume and coordination number (6-9) and different polyhedral compressibilities, together with the observation of significant amounts of alumina in compositions of some natural tilleyite assemblages, suggests that post-tilleyite structure has the potential to accommodate cations with different sizes and valencies.
DS2001-1018
2001
Marques, F.O.Sautter, V., Duchene, S., Marques, F.O.New analytical and numerical geospeedometers tested on garnet pyroxenites from Braganca Nappe Complex.Tectonophysics, Vol. 342, No. 1-2, Dec. pp. 39-59.Portugal, northeastGeospeedometry
DS1994-0261
1994
Marques, F.R.V.Cardoso, F.A.C.M., Rosa, J.W.C., Marques, F.R.V.Group velocity of Rayleigh waves in S America, Atlantic and the crustal And upper mantle structure of regions.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 108-110.BrazilMantle, Geophysics -Rayleigh waves
DS2000-0618
2000
Marques, I.S.Marques, I.S.Mantle sources of the Parana magmatic provinceIgc 30th. Brasil, Aug. abstract only 4p.Brazil, Ponta GrossaMagmatism
DS1993-1242
1993
Marques, J.M.Pinna, P., Jourde, G., Calvez, J.Y., Mroz, J.P., Marques, J.M.The Mozambique Belt in northern Mozambique: Neoproterozoic 1100-850 Macrustal growth and tectogenesis and superimposed Pan-African 800-550 MatectonisM.Precambrian Research, Vol. 62, No. 1-2, April pp. 1-60GlobalTectonics, Mozambique
DS202011-2061
2020
Marques, L.Speciale, S., Censi, P., Gomes, C., Marques, L.Carbonatites from the southern Brazilian platform: a review. II: isotopic evidences.Open Geosciences ( researchgate), 26p. PdfSouth America, Brazilcarbonatite

Abstract: Early and Late Cretaceous alkaline and alkaline-carbonatitic complexes from southern Brazil are located along the main tectonic lineaments of the South America Platform. Calcium-, magnesium-, and ferrocarbonatites are well represented and frequently associated even in the same complex. Primary carbonates present significant variations in C-O isotopic compositions, which are mainly due to isotope exchange with H2O-CO2-rich hydrothermal fluids, whereas fractional crystallization or liquid immiscibility probably affects the d18O and d13C values by no more than 2d‰ Our isotope exchange model implies that the most significant isotopic variations took place in a hydrothermal environment, e.g., in the range 400-80°C, involving fluids with the CO2/H2O ratio ranging from 0.8 to 1. Sr-Nd-Pb isotope systematics highlight heterogeneous mixtures between HIMU and EMI mantle components, similar to the associated alkaline rocks and the flood tholeiites from southern Brazil. In spite of the strong variation shown by C-O isotopes, Sr-Nd-Pb-Os isotopic systematics could be related to an isotopically enriched source where the chemical heterogeneities reflect a depleted mantle "metasomatized" by small-volume melts and fluids rich in incompatible elements. These fluids are expected to have promoted crystallization of K-rich phases in the mantle, which produced a veined network variously enriched in LILE and LREE. The newly formed veins (enriched component) and peridotite matrix (depleted component) underwent a different isotopic evolution with time as reflected by the carbonatites. These conclusions may be extended to the whole Paraná-Etendeka system, where isotopically distinct parent magmas were generated following two main enrichment events of the subcontinental lithospheric mantle at 2.0-1.4 and 1.0-0.5?Ga, respectively, as also supported by Re-Os systematics. The mantle sources preserved the isotopic heterogeneities over a long time, suggesting a nonconvective lithospheric mantle beneath different cratons or intercratonic regions. Overall, the data indicate that the alkaline-carbonatitic magmatism originated from a locally heterogeneous subcontinental mantle.
DS1994-1108
1994
Marques, L.S.Marques, L.S., Piccirillo, E.M.What was the role of Tristan da Cunha mantle plume in the Parana flood basalt generation?International Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts pp. 49-51.BrazilMagma, Mantle plume
DS200712-0912
2007
Marques, L.S.Rosset, A., De Min, A., Marques, L.S., Macambira, M.J.B., Ernesto, M., Renne, P.R., Piccrillo, E.M.Genesis and geodynamic significance of Mesoproterozoic and Early Cretaceous tholeiitic dyke swarms from the Sao Francisco Craton, Brazil.Journal of South American Earth Sciences, Vol. 24, 1, June pp. 69-92.South America, BrazilDyke swarms
DS201801-0071
2017
Marques, L.S.Teixeira, W., Oliveira, E.P., Marques, L.S.Nature and evolution of the Archean crust of the Sao Francisco Craton.Heibron, H. et al. eds. Sao Francisco Craton, eastern Brazil, Regional geology reviews., Chapter 3, pdfSouth America, BrazilGeology

Abstract: We overview the Archean tectonic framework the São Francisco craton based on geologic constraints, integrated geochronologic interpretation and isotopic-geochemical evidence of basement rocks. U-Pb provenance studies of Archean and Paleoproterozoic supracrustal sequences are also used to provide additional inferences about the geodynamic scenario. The Archean rocks crop out mainly in two large areas in the southern and northern portions of the craton, surrounded and/or in tectonic contact with Paleoproterozoic orogenic belts. The ancient substratum is essentially composed of medium- to high-grade gneissic-migmatitic rocks including TTG suites and coeval granite-greenstone associations that collectively provide an isotopic record as old as 4.1 Ga. The combined U-Pb and Sm-Nd TDM age peaks coupled with U-Pb inherited ages in detrital zircons from the supracrustal sequences indicate that very ancient continental crust (?3.5 Ga) exist, particularly in the northern portion of the craton. Mesoarchean events are episodic between 3.6-3.3 and 3.2-2.9 Ga, as for the Neoarchean (2.8-2.6 Ga) in both cratonic portions. This isotopic record indicates a protracted Archean history for the São Francisco craton, highlighted by peculiar tectonic-metamorphic histories of the basement rocks. From a tectonic point of view the compiled data concur with a diachronic evolution from Paleo- to Neoarchean times by means of juvenile accretion/differentiation events characterized by multiple TTG plutonism in genetic association with greenstone belts, coupled with partial melting events of earlier-formed material. All ancient basement complexes and/or continental blocks assembled diachronically during the Late Neoarchean by convergence-related processes akin to plate dynamics. Late-tectonic K-rich granitoids, mafic-ultramafic complexes and mafic dikes collectively mark the Neoarchean thickening and final cratonization of the continental crust.
DS200612-0870
2005
Marques, R.Marques, R.Lundas - the stones of death Angola's deadly diamonds. Human rights abuses in the Lunda Provinces, 2004.google.com Lundas - stones of death, March 9, 73p. free downloadAfrica, AngolaHistory - conflict diamonds
DS201507-0324
2015
Marques de Morais, R.Marques de Morais, R.Blood diamonds: torture and corruption in Angola. IN ENGLISH publ originally in Portugal in 2011.Diamonds.net, English translation 156p. Pdf availableAfrica, AngolaBook
DS2001-0406
2001
Marquette, G.Gray, J.T., Gosse, J.C., Marquette, G.Weathering zones in the Torngat Mountains Labrador, ice sheet thickness and basal thermal regime.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.54, abstract.Quebec, Ungava, LabradorGeomorphology, Laurentide Ice Sheet
DS2001-0238
2001
MarquezDe Ignacio, C., Lopex, I., Oyarzun, MarquezThe northern Patagonia Somuncura plateau basalts: a product of slab induced shallow asthenospheric upwellTerra Nova, Vol. 13, pp. 117-21.Patagonia, South AmericaSubduction, Basalt
DS1993-0956
1993
Marquez, M.Mahlburg Kay, S., Ramos, V.A., Marquez, M.Evidence in Cerro Pampa volcanic rocks for slab melting prior to Ridge-Trench collision in southern South AmericaJournal of Geology, Vol. 101, No. 6, November pp. 703-714Argentina, PatagoniaAdakite flows, Magmatic, melt
DS200612-1025
2006
Marquez, M.Pankhurst, R.J., Rapela, C.W., Fanning, C.M., Marquez, M.Gondwanide continental collision and origin of Patagonia.Earth Science Reviews, Vol. 76, 3-4, June pp. 235-257.South AmericaTectonics
DS1994-1109
1994
Marquez, M.J.Marquez, M.J., et al.Depositos y manifestaciones minerales de la Cordillera Patagonia yFueguinaActas del Encuentro International de Mineria, Vol. 1, pp. 66-83ArgentinaMineral deposits, Overview
DS201906-1351
2019
Marquis, E.Smith, M.P., Estrade, G., Marquis, E., Goodenough, K., Nason, P., Xu, C., Kynicky, J., Borst, A.M., Finch, A.A., Villanova de Benevent, C.Ion adsorption deposits: a comparison of deposits in Madagascar and China.3rd International Critical Metals Meeting held Edinburgh, 1p.abstract p. 53.Africa, Madagascar, ChinaREE

Abstract: Link to presentation pdf.
DS201909-2037
2019
Marquis, E.Estrade, G., Marquis, E., Smith, M., Goodenough, K.,Nason, P.REE concentration processes in ion absorption deposits: evidence from the Ambohimirahavavy alkaline complex in Madagascar.Ore Geology Reviews, in press available, 21p. pdfAfrica, MadagascarREE
DS1994-0799
1994
Marquis, G.Hyndman, R.D., Vanyan, L.L., Marquis, G., Law, L.K.The origin of electrically conductive lower continental crust: saline wateror graphite?Physics of the Earth and Planetary Interiors, Vol. 81, pp. 325-344.MantleGeophysics -magnetotellurics, Graphite, carbon
DS1996-0305
1996
Marquis, R.Cousineau, P.A., Marquis, R.Contrasting fold styles in a volcano-sedimentary successionCanadian Journal of Earth Sciences, Vol. 33, No. 8, August, pp. 1193-1200Quebec, AppalachiaBasin, structure, Basalts
DS1996-0994
1996
Marquis, R.Morin, D., Marquis, R., Jebrak, M.Un diatreme phreatomagmatique montregien dans les Appalaches du QuebecCanadian Journal of Earth Sciences, Vol. 33, No. 5, May pp. 649-655.QuebecGeophysics -magnetics, breccia, Basanite
DS1994-1110
1994
Marr, R.A.Marr, R.A., Baker, D.R., Williams-Jones, A.E.The role of halogens in the speciation of alkali silicate minerals infelsic, peralkaline rocks: an experimental study.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.GlobalAlkaline rocks, Halogens
DS202012-2234
2020
Marras, G.Mikhailenko, D.S., Stagno, V., Korsakov, A.V., Andreozzi, G.B., Marras, G., Cerantola, V., Malygina, E.V.Redox state determination of eclogite xenoliths from Udachnaya kimberlite pipe ( Siberian craton), with some implications for the graphite/diamond formation.Contributions to Mineralogy and Petrology, Vol. 175, 107, 17p. PdfRussiadeposit - Udachnaya

Abstract: The formation of diamonds within eclogitic rocks has been widely linked to the fate of carbon during subduction and, therefore, referred to conditions of pressure, temperature, and oxygen fugacity (fo2). Mantle-derived eclogite xenoliths from Udachnaya kimberlite pipes represent a unique window to investigate the formation of carbon-free, graphite-diamond-bearing and diamond-bearing rocks from the Siberian craton. With this aim, we exploited oxy-thermobarometers to retrieve information on the P-T-fo2 at which mantle eclogites from the Siberian craton equilibrated along with elemental carbon. The chemical analyses of coupled garnet and omphacitic clinopyroxene were integrated with data on their iron oxidation state, determined both by conventional and synchrotron 57Fe Mössbauer spectroscopy. The calculated fo2s largely vary for each suite of eclogite samples from 0.10 to - 2.43 log units (?FMQ) for C-free eclogites, from - 0.01 to - 2.91 (?FMQ) for graphite-diamond-bearing eclogites, and from - 2.08 to - 3.58 log units (?FMQ) for diamond-bearing eclogites. All eclogite samples mostly fall in the fo2 range typical of diamond coexisting with CO2-rich water-bearing melts and gaseous fluids, with diamondiferous eclogites being more reduced at fo2 conditions where circulating fluids can include some methane. When uncertainties on the calculated fo2 are taken into account, all samples essentially fall within the stability field of diamonds coexisting with CO2-bearing melts. Therefore, our results provide evidence of the potential role of CO2-bearing melts as growth medium on the formation of coexisting diamond and graphite in mantle eclogites during subduction of the oceanic crust.
DS1990-0446
1990
Marrett, R.Emerman, S.H., Marrett, R.Why dikes?Geology, Vol. 18, No. 3, March pp. 231-233GlobalDikes, Overview-ductile deformation
DS1991-1060
1991
Marrett, R.Marrett, R., Allmendinger, R.W.Estimates of strain due to brittle faulting: sampling of faultpopulationsJournal of Structural Geology, Vol. 13, No. 6, pp. 735-738GlobalStructure, Sampling -faults
DS1992-1001
1992
Marrett, R.Marrett, R., Emerman, S.H.The relations between faulting and mafic magmatism in the Altiplano Puna Plateau (Central Andes).Earth and Planetary Science Letters, Vol. 112, pp. 53-59.Andes, South AmericaMagmatism, Tectonics
DS1994-1111
1994
Marrett, R.A.Marrett, R.A., et al.Late Cenozoic tectonic evolution of the Puna Plateau adjacent foreland, northwestern Argentine AndesJournal of South American Earth Sciences, Vol. 7, No. 3, April pp. 179-208ArgentinaTectonics
DS1994-0765
1994
Marriner, G.Hergt, J.M., Storey, M., Marriner, G., Tarney, J.Trace element and isotopic compositions of the picritic rocks from CuracaoIsland.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 94-96.GlobalGeochemistry, Picrites
DS1996-0728
1996
Marriner, G.F.Kerr, A.C., Marriner, G.F., Duncan, R.A.The petrogenesis of Gorgona komatiites, picrites basalts: new field, petrographic and geochem. constraintsLithos, Vol. 37, No. 2/3, April pp. 245-260GlobalKomatiites, Petrography
DS1997-0587
1997
Marriner, G.F.Kerr, A.C., Marriner, G.F., Sinton, C.W.Cretaceous basaltic terranes in western Colombia: elemental chronological and Sr neodymium isotopic constraintsJournal of Petrology, Vol. 38, No. 6, June, pp. 677-702ColombiaPetrogenesis, Basalts
DS200512-0337
2004
Marriner, G.F.Gill, R.C., Aparicio, A., El Azzouzi, M., Hernandez, J., Thirlwall, M.F., Bourgois, J., Marriner, G.F.Depleted arc volcanism in the Alboran Sea and shoshonitic volcanism in Morocco: geochemical and isotopic constraints on Neogene tectonic processes.Lithos, Vol. 78, 4, pp. 363-388.Africa, MoroccoShoshonite
DS202010-1866
2020
Marrocchi, Y.Piani, L., Marrocchi, Y., Rigaudier, T.Earth's water may have been inherited from material similar to enstatite chondrite metorites.Science, Vol. 369, 6507, pp. 110-1113. doi. 10.1126/ science.aba.1948Mantlewater

Abstract: The abundances of Earth's chemical elements and their isotopic ratios can indicate which materials formed Earth. Enstatite chondrite (EC) meteorites provide a good isotopic match for many elements but are expected to contain no water because they formed in the hot inner Solar System. This would require Earth's water to be from a different source, such as comets. Piani et al. measured hydrogen contents and deuterium/hydrogen ratios (D/H) in 13 EC meteorites (see the Perspective by Peslier). They found far more hydrogen than is commonly assumed, with D/H close to that of Earth's mantle. Combining these data with cosmochemical models, they show that most of Earth's water could have formed from hydrogen delivered by EC meteorites.
DS1997-0411
1997
Marrs, R.Gill, C., Marrs, R.Detection of kimberlite pipes in the Colorado - Wyoming State Line District using AVARIS.Twelfth Geologic Remote Sensing, Nov. 17th., AbstractsColorado, WyomingGeophysics - remote sensing, AVARIS
DS1982-0397
1982
Marrs, R.W.Marrs, R.W., Hausel, W.D.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Kimberlite Province. #1Report Submitted To Nasa/jet Propulsion Laboratory, First Qu, 3P.Colorado, Wyoming, United States, State Line, Rocky MountainsKimberlite, Geophysics, Soil Sampling, Geochemistry
DS1982-0398
1982
Marrs, R.W.Marrs, R.W., Hausel, W.D.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Kimberlite Province. #2Report Submitted To Nasa/jet Propulsion Laboratory Second Qu, 2P.Colorado, Wyoming, United States, State Line, Rocky MountainsKimberlite, Multispectral Remote Sensing, Geophysics
DS1983-0433
1983
Marrs, R.W.Marks, J.E., Marrs, R.W.Remote Sensing Exploration for Poorly Exposed Kimberlite In the Colorado-Wyoming Region.Geological Survey WYOMING, Publishing INF. Circular No. 19, PP. 11-13.United States, Colorado, Wyoming, State Line, Rocky MountainsLandsat
DS1984-0483
1984
Marrs, R.W.Marrs, R.W.Spectral Detection of KimberliteAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) PREPRINT., No. 84-343, 8P.United States, Wyoming, State Line, Rocky MountainsRemote Sensing
DS1984-0484
1984
Marrs, R.W.Marrs, R.W., Marks, J., Hausel, W.D., Albert, K.G.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Province. #2Nasa Jet Propulsion Laboratory, Final Report Dated Sept. 28t, 70P.United States, Colorado, Wyoming, State Line, Rocky MountainsRemote Sensing, Geochemistry, Sampling, Prospecting, Geophysics
DS1984-0485
1984
Marrs, R.W.Marrs, R.W., Marks, J.E., Hausel, W.D., Albert, G.K.Detection of Diamond Bearing Kimberlites in the Colorado Wyoming Province. #1International Symposium on Remote Sensing of Environment., THIRD THEMATIC CONFERENCE, APRIL 16TH.-19TH. 11P.United States, State Line, Colorado, WyomingLandsat, Remote Sensing, Geophysics, Analyses, Diatreme
DS1984-0486
1984
Marrs, R.W.Marrs, R.W., Raines, G.L.Tectonic Framework of Powder River Basin, Wyoming and Montana Interpreted from Land sat Imagery.American Association Petrol. Geol., Vol. 68, No. 11, NOVEMBER PP. 1718-1731.United States, Montana, Wyoming, Rocky MountainsTectonics, Remote Sensing, Lineaments, Sedimentation
DS1993-0973
1993
Mars, P.J.Mars, P.J., MacArthur, B.T., Pirie, J.Canadian diamond exploration.. high risk.. high reward. Background-historical and overview of current northwest Territories play to date June 11, 1993.Bunting Warburg Inc. Research Report, June 11, 23p.Northwest TerritoriesNews item, Promotional overview
DS2002-1735
2002
Marschall, H.Woodland, A.B., Seitz, H.M., Altherr, R., Marschall, H., Olker, B., Ludwig, T.Li abundances in eclogite minerals: a clue to a crustal or mantle origin?Contributions to Mineralogy and Petrology, Vol. 143, 5, pp.587-601.MantleEclogites - lithium
DS2002-1736
2002
Marschall, H.Woodland, A.B., Seitz, H.M., Altherr, R., Marschall, H., Olker, B., Ludwig, T.Li abundances in eclogite minerals: a clue to a crustal or mantle origin?Contributions to Mineralogy and Petrology, Vol.143,5, Aug.pp.587-601.MantleMineralogy - ecologite
DS200712-0685
2007
Marschall, H.Marschall, H., Von Strandmann, P.P., Seitz, H-M., Elliott, T.Heavy lithium in subducted slabs.Plates, Plumes, and Paradigms, 1p. abstract p. A625.MantleSubduction
DS200912-0287
2009
Marschall, H.Hawkesworth, C., Storey, C., Dhuime, B., Marschall, H., Pietranik, A., Kemp, T.The generation, evolution and preservation of the continental crust.Goldschmidt Conference 2009, p. A505 Abstract.MantleZircon geochronology
DS200712-0686
2007
Marschall, H.R.Marschall, H.R., Pogge Von Strandemann, P.A.E., Seitz, H-M., Elliott, T., Niu, Y.The lithium isotopic composition of orogenic eclogites and deep subduction zones.Earth and Planetary Science Letters, In press availableMantleSubduction
DS200712-0687
2007
Marschall, H.R.Marschall, H.R., Pogge von Stranmann, P.A.E., Seit, H-M., Elliott, NiuThe lithium isotopic composition of orogenic eclogites and deep subducted slabs.Earth and Planetary Science Letters, Vol. 262, 3-4, Oct. 30, pp. 563-580.MantleSubduction
DS200812-0715
2008
Marschall, H.R.Marschall, H.R., Pogge Von Strandmann, A.E.Li and Mg exchange between eclogite lenses and their host rocks: evidence from isotope profiles.Goldschmidt Conference 2008, Abstract p.A594.TechnologyEclogite
DS200912-0282
2009
Marschall, H.R.Harlov, D.E., Marschall, H.R.Mechanisms of metasomatic reactions.Mineralogy and Petrology, Vol. 95, 3-4, pp. 159-161.MantleMetasomatism
DS201804-0689
2018
Marschall, H.R.Forster, M.W., Prelevic, D., Schmuck, H.R., Buhre, S., Marschall, H.R., Mertz-Kraus, R., Jacob, D.E.Melting phologopite rich MARID: lamproites and the role of alkalis in olivine liquid Ni partioning.Chemical Geology, Vol. 476, 1, pp. 429-440.Technologylamproites

Abstract: In this study, we show how veined lithospheric mantle is involved in the genesis of ultrapotassic magmatism in cratonic settings. We conducted high pressure experiments to simulate vein + wall rock melting within the Earth's lithospheric mantle by reacting assemblages of harzburgite and phlogopite-rich hydrous mantle xenoliths. These comprised a mica-, amphibole-, rutile-, ilmenite-, diopside (MARID) assemblage at 3-5 GPa and 1325-1450 °C. Melting of the MARID assemblages results in infiltration of melt through the harzburgite, leading to its chemical alteration. At 3 and 4 GPa, melts are high in K2O (> 9 wt%) with K2O/Na2O > > 2 comparable to anorogenic lamproites. Higher pressures and temperatures (5 GPa/1450 °C) lead to increasing MgO contents of the melt and to some extent lower K2O contents (5-7 wt%) at equally high K2O/Na2O ratios. Our experiments provide insights into the role of alkalis in nickel-partitioning (DNi) between olivine and ultrapotassic melt. We observe that the high contents of Na, K, and Al are indicative of high DNi values, implying that the melt polymerization is the dominant factor influencing the olivine/melt nickel partitioning. The change of DNi as a function of melt composition results in a pressure independent, empirical geothermometer: Element oxides represent the composition of the glass (in wt%), and DNi is the liquid/olivine Ni-partitioning coefficient. We propose that this geothermometer is applicable to all natural silicate melts that crystallized olivine in a temperature interval between 1000 and 1600 °C. Application to glass-olivine pairs from calc-alkaline settings (Mexico), MORB (East Pacific Rise), and OIB (Hawaii) yielded reasonable values of 996-1199 °C, 1265 °C, and 1330 °C, respectively.
DS201805-0942
2018
Marschall, H.R.Cruz-Uribe, A.M., Marschall, H.R., Gaetani, G.A., Le Roux, V.Generation of alkaline magmas in subduction zones by partial melting of melange diapirs - an experimental study.Geology, Vol. 48, 4, pp. 343-346.Technologysubduction

Abstract: Alkaline lavas occur globally in subduction-related volcanic arcs. Conventional models for the origin of these lavas typically invoke a multi-stage process in which mantle wedge peridotite, enriched in phlogopite and/or amphibole due to prior metasomatism, partially melts during infiltration by fluids and melts derived from subducted oceanic lithosphere. However, geochemical systematics in the majority of subduction-related alkaline lavas require physical mixing of subducted components and peridotite prior to partial melting. This can be explained by the mélange diapir model, which predicts the generation of arc magmas during advection of buoyant material from the slab-wedge interface into the mantle wedge below arcs. Here we report results from experiments in which natural mélange materials were partially melted at upper mantle conditions to produce alkaline magmas. Partial melts produced in our experiments have trace-element abundance patterns that are typical of alkaline arc lavas, such as enrichment in large ion lithophile elements (LILEs) and depletion in Nb and Ta. These results favor generation of alkaline magmas in the arc and backarc regions of subduction zones by partial melting of mélange materials rather than previously metasomatized peridotite.
DS201907-1545
2019
Marschall, H.R.Forster, M.W., Foley, S.F., Marschall, H.R., Alard, O., Buhre, S.Melting of sediments in the deep mantle produces saline fluid inclusions in diamonds.Science Advances, Vol. 5, 5, eaau 2620 7p.Mantlediamond inclusions

Abstract: Diamonds growing in the Earth’s mantle often trap inclusions of fluids that are highly saline in composition. These fluids are thought to emerge from deep in subduction zones and may also be involved in the generation of some of the kimberlite magmas. However, the source of these fluids and the mechanism of their transport into the mantle lithosphere are unresolved. Here, we present experimental results showing that alkali chlorides are stable solid phases in the mantle lithosphere below 110 km. These alkali chlorides are formed by the reaction of subducted marine sediments with peridotite and show identical K/Na ratios to fluid inclusions in diamond. At temperatures >1100°C and low pressures, the chlorides are unstable; here, potassium is accommodated in mica and melt. The reaction of subducted sediments with peridotite explains the occurrence of Mg carbonates and the highly saline fluids found in diamonds and in chlorine-enriched kimberlite magmas.
DS1992-1002
1992
Marschallinger, R.Marschallinger, R.Interface programs to enable full 3-D geological modeling with acombination of Auto CAD and SURFER.Computers and Geosciences, Vol. 17, No. 10, pp. 1383-1394GlobalComputer, Program -AutoCAD, SURFER.
DS1996-0888
1996
Marschallinger, R.Marschallinger, R.A VOXEL visualization and analysis system based on autocadComputers and Geosciences, Vol. 22, No. 4, pp. 379-386GlobalComputer, Program -VOXEL autocad
DS2001-0733
2001
Marschallinger, R.Marschallinger, R., Johnson, S.E.Presenting 3 D models of geological materials on the World Wide WebComputers and Geosciences, Vol. 27, No. 4, pp. 467-76.GlobalComputer - models ?
DS1970-0759
1973
Marsden, .M.A.H.Mcandrew, J., Marsden, .M.A.H.Geomorphology of the Western District Volcanic Plains, Lakes and Coastline.In:regional Guide To Victorian Geology, PP. 100-112.Australia, VictoriaGeomorphology, Lake Ballenmerri, Kimberlite
DS1989-0944
1989
Marsden, D.Marsden, D.Layer cake depth conversionGeophysics: The leading Edge of Exploration, Vol. 8, No. 1, January pp. 10-14GlobalGeophysics, Seismics
DS201605-0877
2016
Marsden, H.Naismith, A., Howell, G., Marsden, H.Design and development of a decline shaft through poorly consolidated Kalahari deposits at Ghaghoo diamond mine.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 1-14.Africa, BotswanaDeposit - Ghaghoo
DS201605-0911
2016
Marsden, H.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
DS2000-0619
2000
Marsella, K.A.Marsella, K.A., Bierman, P., Davis, P.T., Caffee, M.W.Cosmogenic Berylium and Aluminum ages for the last Glacial Maximum eastern Baffin Island, Arctic Canada.Geological Society of America (GSA) Bulletin., Vol. 112, No., Aug., pp. 1296-1312.Northwest Territories, Baffin IslandGeomorphology, Aluminum, Berylium, Geochronology
DS1996-0890
1996
MarshMarsh, McLennanDirectors' and officers liability: an overviewMarsh and McLennan, 20p. (small size pages=10)CanadaLegal, Directorships
DS1988-0440
1988
Marsh, B.D.Marsh, B.D.Crystal capture, sorting and retention in convecting magmaGeological Society of America (GSA) Bulletin, Vol. 100, No. 11, November pp. 1720-1737GlobalLayered intrusion, Magma
DS1989-0945
1989
Marsh, B.D.Marsh, B.D.On convective style and vigor in sheet-like magma chambersJournal of Petrology, Vol. 30, No. 3, June pp. 479-530GlobalLayered intrusion, Tectonics
DS1994-1184
1994
Marsh, B.D.Meyers, J.D., Marsh, B.D.Subduction zone magmatism: a plausible case for slab meltingEos, Vol. 75, No. 16, April 19, p. 352.MantleSubduction
DS1996-0889
1996
Marsh, B.D.Marsh, B.D.Solidification fronts and magmatic evolutionMineralogical Magazine, Vol. 60, No. 1, Feb pp. 5-40GlobalMagmatic processes, Magmatic evolution -fronts
DS1998-0944
1998
Marsh, B.D.Marsh, B.D.On the interpretation of crystal size distributions in magmatic systemsJournal of Petrology, Vol. 39, No. 4, Apr. pp. 553-600GlobalMagma, Crystallinity, characteristics
DS200712-0432
2007
Marsh, B.D.Hersum, T.G., Marsh, B.D.Igneous textures: on the kinetics behind the words.Elements, Vol. 3, 4, August pp. 247-252.TechnologyClassification
DS200712-0688
2006
Marsh, B.D.Marsh, B.D.Dynamics of magmatic systems.Elements, Vol. 2, 5, October pp. 287-292.MantleMagmatism
DS2002-0995
2002
Marsh, E.E.Marsh, E.E., Goldfarb, R.J., Day, W.C.Integrated methods for discovery: global exploration in the twenty first century.abstracts.Society of Economic Geologists, Abstract volume No. 9, 150p.GlobalBook - table of contents
DS1940-0089
1944
Marsh, J.H.Marsh, J.H.Skeleton Coast (1944)Cape Town: Hodder And Stoughton., 120P.Southwest Africa, NamibiaTravelogue, Kimberley
DS1975-0802
1978
Marsh, J.H.Marsh, J.H.Skeleton Coast (1978)Cape Town: Marshes Books, 142P.Southwest Africa, NamibiaTravelogue, Klimlib
DS1970-0753
1973
Marsh, J.S.Marsh, J.S.Alkaline Igneous Rocks of the Coastal Belt South of Luderitz,southwest Africa a Petrological Study.Ph.d. Thesis, University Cape Town., Southwest Africa, NamibiaPetrology
DS1975-0128
1975
Marsh, J.S.Marsh, J.S.The Luderitz Alkaline Province, Southwest Africa. Three ParGeological Society of South Africa Transactions, Vol. 78, No. 2, PP. 215-224.; PP. 225-233.; Vol. 79, No. 2, PSouthwest Africa, NamibiaUltrabasic Alkaline Rocks, Petrology
DS1981-0284
1981
Marsh, J.S.Marsh, J.S., Hawkesworth, C.J., Moore, A.E.Strontium and Neodymium Isotopes in Tertiary Alkaline Volcanics in South western Africa.Geocongress '81 Open Session., ABSTRACT VOLUME, PP. 33-35.South AfricaNamaqualand, Melilitite, Spiegel River, Klaasvoogds, Garies
DS1987-0435
1987
Marsh, J.S.Marsh, J.S.Evolution of a strongly differentiated suite of phonolites from the Klinghardt Mountains, NamibiaLithos, Vol. 20, pp. 41-58NamibiaPetrology, Classification
DS1989-1224
1989
Marsh, J.S.Pirajno, F., Smithies, R.H., Marsh, J.S.An overview of two continental alkaline igneous provinces in NamibiaNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 215 Abstract held June 25-July 1Namibia, Southwest AfricaAlkaline rocks
DS1989-1300
1989
Marsh, J.S.Rogers, N.W., Marsh, J.S.Mantle xenoliths and Archean basalts from South Africa: implications for local heterogeneity in the ArcheanmantleLpi Technical Report, No. 89-05, pp. 75-78South AfricaMantle xenoliths
DS1997-1108
1997
Marsh, J.S.Stiefenhofer, J., Viljoen, K.S., Marsh, J.S.Petrology and geochemistry of the Eldor carbonatite complex LabradorTrough, Quebec.Contrib. Mineralogy and Petrology, Vol. 127, No. 1-2, pp. 147-158.BotswanaGeochemistry, Deposit - Letlhkane
DS1998-1363
1998
Marsh, J.S.Smithlies, R.H., Marsh, J.S.The Marinkas Quellen carbonatite complex; carbonatite magmatism with an uncontaminated depleted mantle...Chemical Geology, Vol. 148, No. 3-4, June 15, pp. 201-212.Namibia, southSignature, continental setting, geochemistry, Deposit - Marinkas Quellen
DS1999-0289
1999
Marsh, J.S.Harris, C., Marsh, J.S., Milner, S.C.Petrology of the alkaline core of the Messum igneous complex, : evidence or the progressively decreasing ...Journal of Petrology, Vol. 40, No. 9, Sept. pp. 1377-98.NamibiaCrustal contamination, Alkaline rocks
DS2003-0877
2003
Marsh, J.S.Marsh, J.S.Review of South African research on volcanic and related rocks and mantle derivedSouth African Journal of Science, Vol. 99, No. 7/8, pp. 381-88.MantlePetrology - technology
DS2003-1289
2003
Marsh, J.S.Skinner, E.M.W., Marsh, J.S.Kimberlite eruption processes8 Ikc Www.venuewest.com/8ikc/program.htm, Session 1, AbstractSouth AfricaGeology, economics, magmatic, phreatomagmatic, Magmatism
DS200412-1230
2003
Marsh, J.S.Marsh, J.S.Review of South African research on volcanic and related rocks and mantle derived materials 1999-2002.South African Journal of Geology, Vol. 99, no. 7/8, pp. 381-88.MantlePetrology - technology
DS200412-1846
2003
Marsh, J.S.Skinner, E.M.W., Marsh, J.S.Kimberlite eruption processes.8 IKC Program, Session 1, AbstractAfrica, South AfricaGeology, economics, magmatic, phreatomagmatic Magmatism
DS200612-0526
2006
Marsh, J.S.Hanson, E.K., Moore, J.M., Robey, J., Bordy, E.M., Marsh, J.S.Re-estimation of erosion levels in Group I and II kimberlites between Lesotho, Kimberley and Victoria West, South Africa.Emplacement Workshop held September, 5p. extended abstractAfrica, South Africa, LesothoCrustal xenoliths
DS200612-1319
2006
Marsh, J.S.Skinner, E.M.W., Marsh, J.S.The emplacement of class 1 kimberlites - part 2, petrographic evidence.Emplacement Workshop held September, 5p. abstractGlobalTransition zones - root, diatremes, crater
DS200612-1320
2006
Marsh, J.S.Skinner, E.M.W., Marsh, J.S.The emplacement of class 1 kimberlites - part 1, evidence of geological features.Emplacement Workshop held September, 5p. abstractGlobalZones - root, diatremes, crater
DS201012-0266
2009
Marsh, J.S.Hanson, E.K., Moore, J.M., Bordy, E.M., Marsh, J.S., Howarth, G., Robey, J.V.A.Cretaceous erosion in central South Africa: evidence from upper crustal xenoliths in kimberlite diatremes.South African Journal of Geology, Vol. 112, 2, pp. 125-140.Africa, South AfricaGeomorphology
DS1960-0605
1965
Marsh, P.S.Stearns, R.G., Marsh, P.S.Preliminary Conclusions from a Regional Gravity Survey of The Wells Creek Basin Structure, Houston and Stewart Counties.Tennessee Academy of Science Journal, Vol. 40, No. 2, P. 67, (abstract.).GlobalKimberlite, Geophysics
DS1986-0124
1986
Marsh, S.W.Carlson, J.A., Marsh, S.W.Discovery of the George Creek, Colorado kimberlite dikes #1Proceedings of the Fourth International Kimberlite Conference, Held, No. 16, pp. 443-445ColoradoDiamond exploration
DS1987-0088
1987
Marsh, S.W.Carlson, J.A., Marsh, S.W.Discovery of the George Creek, Colorado Kimberlite dikes #2Preprint from author, 26p. 5 figsColoradoUSA, Geophysics
DS1989-0213
1989
Marsh, S.W.Carlson, J.A., Marsh, S.W.Discovery of George Creek, Colorado kimberlite dikesGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 1169-78ColoradoExploration history, Geophysics, Geochemistry
DS1990-0511
1990
Marshak, S.Gang Lu, Marshak, S., Kent, D.V.Characteristics of magnetic carriers responsible for Late Paleozoic remagnitization in carbonate strat a of the Mid-continent, USAEarth and Planetary Science Letters, Vol. 99, pp. 351-361MidcontinentGeophysics -remagnetization, Tectonics
DS1992-1003
1992
Marshak, S.Marshak, S., Alkmim, F.F., Jordt-Evangelista, H.Proterozoic crustal extension and the generation of dome and keel structure in an Archean granite-greenstone terraneNature, Vol. 357, No. 6378, June 11, pp. 491-493BrazilTectonics, Greenstone belts
DS1992-1004
1992
Marshak, S.Marshak, S., Wilkerson, M.S.Effect of overburden thickness on thrust belt geometry and developmentTectonics, Vol. 11, No. 3, June pp. 560-566GlobalTectonics, Thrust belt geometry
DS1994-1344
1994
Marshak, S.Paulsen, T., Marshak, S.Cratonic weak zone in the U.S. continental interior: the Dakota-Carolinacorridor.Geology, Vol. 22, No. 1, January pp. 15-18.Missouri, Illinois, Tennessee, Indiana, KentuckyTectonics, Craton
DS1996-0314
1996
Marshak, S.Cunningham, W.D., Marshak, S., Alkmim, F.F.Structural style of basin inversion at mid-crustal levels: two transects in internal zone ...Precambrian Research, Vol. 77, No. 1-2, March 1, pp. 1-16BrazilBrasiliano Aracuai Belt, Structure
DS1996-0891
1996
Marshak, S.Marshak, S., Paulsen, T.Midcontinent United States fault and fold zones: a legacy of Proterozoic intracratonic extensional tectonism?Geology, Vol. 24, No. 2, Feb. pp. 151-154.Midcontinent, ArkansasTectonics, Structure -faults, folds, Rifting
DS1996-0892
1996
Marshak, S.Marshak, S., Paulsen, T.Fault reaction corridors in continental interiors: a reviewGeological Society of America, Abstracts, Vol. 28, No. 7, p. A-446.MidcontinentStructure - fault
DS1997-0738
1997
Marshak, S.Marshak, S., Tinkham, D., et al.Dome and keel provinces formed during Paleoproterozoic orogenic collapse -core complexes, diapirs ???Geology, Vol. 25, No. 5, May pp. 415-418Brazil, Quadrilatero FerriferoPenokean Orogen, Tectonics
DS1998-0020
1998
Marshak, S.Alkim, F.F., Marshak, S.Transamazonian Orogeny in the Southern Sao Francisco Craton region, evidence for Paleoproterozoic ..Precambrian Research, Vol. 90, No. 1-2, June 30, pp. 29-58Brazil, Minas GeraisTectonics, Quadrilatero Ferrifero, Craton
DS1998-0945
1998
Marshak, S.Marshak, S., Hamburger, M., Van der Pluijm, B.Tectonics of continental interiors..... Penrose Conference ReportGsa Today, Vol. 8, No. 2, Feb. pp. 23-24GlobalTectonics, Precambrian
DS1998-0946
1998
Marshak, S.Marshak, S., Hamburger, M., Van der Pluijm, B.A.Tectonics of continental interiors. Penrose Conference reportGsa Today, Vol. 8, No. 2, Feb. pp. 23-24.GlobalContinental interior, Precambrian, Craton
DS200612-0014
2006
Marshak, S.Alkmim, F.F., Marshak, S., Pedrosa Soares, A.C., Peres, G.G., Cruz, S.C., Whittington, A.Kinematic evolution of the Aracuai West Congo in Brazil and Africa: nutcracker tectonics during the Neoproterozoic assembly of Gondwana.Precambrian Research, Vol. 149, 1-2, pp. 43-64.South America, BrazilTectonics - collisional, orogen
DS201706-1095
2017
Marshak, S.Marshak, S., Domrois, S., Abert, C., Larson, T., Pavlis, G., Hamburger, M., Yang, X., Gilbert, H., Chen, C.The basement revealed: tectonic insight from a digital elevation model of the Great Unconformity, USA cratonic platform.Geology, Vol. 45, 5, pp. 391-394.United Statestectonics - Mid continent

Abstract: Across much of North America, the contact between Precambrian basement and Paleozoic strata is the Great Unconformity, a surface that represents a >0.4 b.y.-long hiatus. A digital elevation model (DEM) of this surface visually highlights regional-scale variability in the character of basement topography across the United States cratonic platform. Specifically, it delineates Phanerozoic tectonic domains, each characterized by a distinct structural wavelength (horizontal distance between adjacent highs) and/or structural amplitude (vertical distance between adjacent lows and highs). The largest domain, the Midcontinent domain, includes long-wavelength epeirogenic basins and domes, as well as fault-controlled steps. The pronounced change in land-surface elevation at the Rocky Mountain Front coincides with the western edge of the Midcontinent domain on the basement DEM. In the Rocky Mountain and Colorado Plateau domains, west of the Rocky Mountain Front, structural wavelength is significantly shorter and structural amplitude significantly higher than in the Midcontinent domain. The Bordering Basins domain outlines the southern and eastern edges of the Midcontinent domain. As emphasized by the basement DEM, several kilometers of structural relief occur across the boundary between these two domains, even though this boundary does not stand out on ground-surface topography. A plot of epicenters on the basement DEM supports models associating intraplate seismicity with the Midcontinent domain edge. Notably, certain changes in crustal thickness also coincide with distinct changes in basement depth.
DS201712-2679
2018
Marshak, S.Chen, C., Hersh, G., Fischer, K.M., Andronicos, C.L., Pavlis, G.L., Hamburger, M.W., Marshak, S., Larson, T., Yang, X.Lithospheric discontinuities beneath the U.S. Midcontinent - signatures of Proterozoic terrane accretion and failed rifting.Earth and Planetary Science Letters, Vol. 481, pp. 223-235.United States, Illinois, Indiana, Kentuckygeophysics - seismics Reelfoot Rift

Abstract: Seismic discontinuities between the Moho and the inferred lithosphere-asthenosphere boundary (LAB) are known as mid-lithospheric discontinuities (MLDs) and have been ascribed to a variety of phenomena that are critical to understanding lithospheric growth and evolution. In this study, we used S-to-P converted waves recorded by the USArray Transportable Array and the OIINK (Ozarks-Illinois-Indiana-Kentucky) Flexible Array to investigate lithospheric structure beneath the central U.S. This region, a portion of North America's cratonic platform, provides an opportunity to explore how terrane accretion, cratonization, and subsequent rifting may have influenced lithospheric structure. The 3D common conversion point (CCP) volume produced by stacking back-projected Sp receiver functions reveals a general absence of negative converted phases at the depths of the LAB across much of the central U.S. This observation suggests a gradual velocity decrease between the lithosphere and asthenosphere. Within the lithosphere, the CCP stacks display negative arrivals at depths between 65 km and 125 km. We interpret these as MLDs resulting from the top of a layer of crystallized melts (sill-like igneous intrusions) or otherwise chemically modified lithosphere that is enriched in water and/or hydrous minerals. Chemical modification in this manner would cause a weak layer in the lithosphere that marks the MLDs. The depth and amplitude of negative MLD phases vary significantly both within and between the physiographic provinces of the midcontinent. Double, or overlapping, MLDs can be seen along Precambrian terrane boundaries and appear to result from stacked or imbricated lithospheric blocks. A prominent negative Sp phase can be clearly identified at 80 km depth within the Reelfoot Rift. This arrival aligns with the top of a zone of low shear-wave velocities, which suggests that it marks an unusually shallow seismic LAB for the midcontinent. This boundary would correspond to the top of a region of mechanically and chemically rejuvenated mantle that was likely emplaced during late Precambrian/early Cambrian rifting. These observations suggest that the lithospheric structure beneath the Reelfoot Rift may be an example of a global phenomenon in which MLDs act as weak zones that facilitate the removal of cratonic lithosphere that lies beneath.
DS2001-0013
2001
Marshal\k, S.Alkmim, F.F., Marshal\k, S., Fonseca, M.A.Assembling West Gondwana in the Neoproterozoic: clues from the Sao Francisco craton region, Brasil.Geology, Vol. 29, No. 4, Apr. pp.319-22.BrazilGondwana, tectonics, Brasiliano orogeny, Craton
DS1994-0650
1994
Marshall, B.Graham, I.T., Franklin, B.J., Marshall, B.Evidence and timing of remobilization in upper mantle peridotiteGeological Society of Australia Abstract Volume, No. 37, pp. 143.MantlePeridotite
DS1998-0930
1998
Marshall, B.Mancini, F., Papunen, H., Savitoki, S., Marshall, B.EPMA analyses and X-ray single crystal refinements of garnets from Arkangelsk kimberlites, northwest Russia.Petrology, Vol. 6, No. 6, Nov-Dec. pp. 546-554.Russia, Arkangelsk, Kola PeninsulaCrystallography, Garnet morphology
DS1996-0893
1996
Marshall, D.Marshall, D.TernPlot: an Excel spreadsheet for ternary diagramsComputers and Geosciences, Vol. 22, No. 6, pp. 697-700GlobalComputers, Program -TernPlot
DS201512-1939
2015
Marshall, D.Mao, M., Simandl, G.J., Spence, J., Marshall, D.Fluorite trace-element chemistry and its potential as an indicator mineral: evaluation of LA-ICP-MS method.Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 251-264.TechnologyRare earths

Abstract: Fluorite (CaF2) belongs to the isometric system, with a cubic, face-centred lattice. Fluorite commonly forms cubes or octahedrons, less commonly dodecahedrons and, rarely, tetrahexahedrons, trapezohedrons, trisoctahedrons, hexoctahedrons, and botyroidal forms. Fluorite is transparent to translucent, and has vitreous luster. It occurs in a variety of colours including purple, green, blue, or yellow, however it can also be colourless, and can exhibit colour zoning, (Staebler et al., 2006). Fluorite from many localities is fl uorescent (Verbeek, 2006). Fluorite density varies from 3.0-3.6 g/cm3, depending to a large extent on inclusions and impurities in the crystal lattice (Staebler et al., 2006), and its hardness is 4 on Mohs scale (Berry et al., 1983). Many single fl uorite crystals display sector zoning, refl ecting preferential substitution and incorporation of trace elements along successive crystal surfaces (Bosce and Rakovan, 2001). The Ca2+ ion in the fl uorite crystal structure can be substituted by Li+, Na+, K+, Mg2+, Mn2+, Fe2+,3+, Zn2+, Sr2+, Y3+, Zr4+, Ba2+, lanthanides ions, Pb2+, Th4+, and U4+ ions (Bailey et al., 1974; Bill and Calas, 1978, Gagnon et al., 2003; Schwinn and Markl, 2005; Xu et al., 2012; Deng et al., 2014). Concentrations of these impurities do not exceed 1% (Deer, 1965) except in yttrofl uorite (Ca,Y)F2-2.33 and cerfl uorite (Ca,Ce)F2-2.33 (Sverdrup, 1968). Fluorite occurs in a variety of rocks, as an accessory and as a gangue mineral in many metalliferous deposits and, in exceptional cases, as the main ore constituent of economic deposits (Simandl, 2009). Good examples of fl uorite mines are Las Cuevas, Encantada-Buenavista (Mexico); St. Lawrence pluton-related veins and the Rock Candy Mine (Canada); El Hamman veins (Morocco) and LeBurc Montroc -Le Moulinal and Trebas deposits (France) as documented by Ruiz et al. (1980), Grogan and Montgomery (1975), González-Partida et al. (2003), Munoz et al. (2005), and Fulton III and Miller (2006). Fluorite also commonly occurs adjacent to or within carbonatites and alkaline complexes (Kogut et al., 1998; Hagni,1999; Alvin et al., 2004; Xu et al., 2004; Salvi and Williams-Jones, 2006); Mississippi Valley-type (MVT) Pb- Zn-F-Ba deposits; F-Ba-(Pb-Zn) veins (Grogan and Bradbury, 1967 and 1968; Baxter et al., 1973; Kesler et al., 1989; Cardellach et al., 2002; Levresse et al., 2006); hydrothermal Fe (±Au, ±Cu) and rare earth element (REE) deposits (Borrok et al., 1998; Andrade et al., 1999; Fourie, 2000); precious metal concentrations (Hill et al., 2000); fl uorite/metal-bearing skarns (Lu et al., 2003); Sn-polymetallic greissen-type deposits (Bettencourt et al., 2005); and zeolitic rocks and uranium deposits (Sheppard and Mumpton, 1984; Cunningham et al., 1998; Min et al., 2005). Ore deposit studies that document the trace element distribution in fl uorite are provided by Möller et al. (1976), Bau et al. (2003), Gagnon et al. (2003), Schwinn and Markl (2005), and Deng et al. (2014). The benchmark paper by Möller et al. (1976) identifi ed variations in the chemical composition of fl uorites according their origin (sedimentary, hydrothermal, or pegmatitic). Recently, Makin et al. (2014) compiled trace-element compositions of fl uorite from MVT, fl uorite-barite veins, peralkaline-related, and carbonatite-related deposits. They showed that fl uorite from MVT and carbonatite deposits can be distinguished through trace element concentrations, and that the REE concentration of fl uorite from veins is largely independent of the composition of the host rock. Based on the physical and chemical properties of fl uorite, its association with a variety of deposit types, and previous studies, it is possible that fl uorite can be used as a proximal indicator mineral to explore for a variety of deposit types. Unfortunately, the compilation by Makin et al. (2014) contained chemical analyses performed at different laboratories using different analytical techniques (including laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), electron microprobe, neutron activation, and ICP-MS), and precision and accuracy varied accordingly. As an orientation survey, herein we present data from fi ve deposits, with two samples from the Rock Candy deposit (British Columbia), and one sample from each of Kootenay Florence (British Columbia), Eaglet (British Columbia), Eldor (Quebec), and Hastie quarry (Illinois) deposits (Table 1). The main objectives of this study are to: 1) assess variations in chemical composition of fl uorite in the samples and deposit types; 2) evaluate relations between analyses made using laser ablation-inductively coupled plasma mass spectrometry on individual grains [LA-ICP-MS(IG)], and those made using laser ablation-inductively coupled plasma mass spectrometry on fused beads [LA-ICP-MS(FB)] and X-ray fl uorescence (XRF); 3) test the use of stoichiometric Ca content as an internal fl uorite standard, such has been done by Gagnon et al. (2003) and Schwinn and Markl, (2005); 4) select the elements that are commonly present in concentrations above the lower limit of detection of LA-ICP-MS and available for constructing discrimination diagrams; 5) consider if our results agree with the preliminary discrimination diagrams of Makin et al. (2014).
DS201811-2573
2015
Marshall, D.Giuliani, G., Branquet, Y., Fallick, A.E., Groat, L.A., Marshall, D.Emerald deposits around the world, their similarities and differences.InColor, December pp. 56-69.Globalemeralds
DS200712-0666
2006
Marshall, D.D.Madsen, J.K., Thorkelson, D.J., Friedman, R.M., Marshall, D.D.Cenozoic to Recent plate configuration in the Pacific Basin: ridge subduction and slab window magmatism in western North America.Geosphere, Vol. 2, pp. 11-34.United States, CanadaSubduction
DS1988-0441
1988
Marshall, D.J.Marshall, D.J., and Mariano, A.N.Cathodoluminescence of geologic materialsUnwin Hyman, Chap. 4, Class I: native elements Diamond pp.37-38, 117GlobalPetrography, Cathodoluminescence
DS1990-0989
1990
Marshall, E.Marshall, E.GE's cool diamonds.. prompt warm wordsScience, Vol. 250, October 5, pp. 25-26GlobalDiamond synthesis, Sietz
DS2002-0996
2002
Marshall, E.Marshall, E.Diamond project Catoca - Government of Republic of Angola. New model of cooperation stabilizes economics.Prospectors and Developers Association of Canada (PDAC) 2002, 1p. abstractAngolaDeposit - Catoca
DS201707-1348
2017
Marshall, E.W.Marshall, E.W., Lassiter, J.C., Barnes, J.D., Luguet, A., Lissner, M.Mantle melt production during the 1.4 Ga Laurentian magmatic event: isotopic constraints from Colorado Plateau mantle xenoliths.Geology, Vol. 45, 6, pp. 519-522.United States, Colorado Plateaumelting - Navajo Volcanics

Abstract: Plutons associated with a 1.4 Ga magmatic event intrude across southwestern Laurentia. The tectonic setting of this major magmatic province is poorly understood. Proposed melting models include anorogenic heating from the mantle, continental arc or transpressive orogeny, and anatexis from radiogenic heat buildup in thickened crust. Re-Os analyses of refractory mantle xenoliths from the Navajo volcanic field (NVF; central Colorado Plateau) yield Re depletion ages of 2.1–1.7 Ga, consistent with the age of the overlying Yavapai and Mazatzal crust. However, new Sm-Nd isotope data from clinopyroxene in peridotite xenoliths from NVF diatremes show a subset of xenoliths that plot on a ca. 1.4 Ga isochron, which likely reflects mantle melt production and isotopic resetting at 1.4 Ga. This suggests that Paleoproterozoic subcontinental lithospheric mantle was involved in the 1.4 Ga magmatic event. Our constraints support a subduction model for the generation of the 1.4 Ga granites but are inconsistent with rifting and anorogenic anatexis models, both of which would require removal of ancient lithosphere.
DS201803-0464
2017
Marshall, E.W.Marshall, E.W., Barnes, J.D., Lassiter, J.C.The role of serpentinite derived fluids in metasomatism of the Colorado Plateau ( USA) lithospheric mantle.Geology, Vol. 45, 12, pp. 1103-1106.United States, Colorado Plateausubduction

Abstract: Subducting serpentinized lithosphere has distinct dD and d18O values compared to normal mantle. Slab-derived fluids that infiltrate the mantle wedge can alter its oxygen and hydrogen isotope composition, raising or lowering the d18O and dD values depending on the nature of the subducted components. Hydrous minerals in peridotite xenoliths from the Colorado Plateau (southwestern USA) have dD values (up to -33‰) much higher than average mantle (-80‰), but similar to dD values of olivine-hosted melt inclusions within arc basalts, suggesting a slab-derived fluid source. Oxygen isotope ratios of olivine from these xenoliths are similar to average mantle, yet display a strong negative correlation with clinopyroxene Ce/Sm, a proxy of metasomatism. This correlation is most simply explained by metasomatism from fluids derived from the serpentinized portion of the Farallon slab. Although d18O values of mantle minerals span a narrow range, integration of stable isotope data with other geochemical tracers can provide new constraints on modern and ancient subduction-related processes, potentially providing a method for probing Archean lithospheric mantle for evidence of early subduction.
DS201809-2068
2018
Marshall, E.W.Marshall, E.W., Lassiter, J.C., Banes. J.B.Understanding the (mis) behaviour of water contents in nominally anhydrous mantle minerals.Goldschmidt Conference, 1p. AbstractMantleperidotites

Abstract: The H/C ratio in earth’s exosphere is higher than it is in the source region of primitive basalts, suggesting an enriched carbon reservoir in the mantle[1]. A plausible explanation is that subduction of carbon may have enriched the mantle in recycled carbon over time. Average basaltic crust contains ~ 2 wt.% CO2 [2], and modeling of slab devolatilisation suggests that subducted carbonate may survive to be transported deeper into the mantle [3]. Carbonated oceanic crust should melt in the transition zone along most subduction geotherms due to a deep trough in the carbonated basalt solidus, and mineral inclusions in superdeep diamonds testify to carbonate melt in their formation [4]. Along cool subduction geotherms carbonate may subduct into the lower mantle, potentially enriching the deep mantle in carbon. Here we report on laser-heated diamond anvil cell experiments in the CaO-MgO-SiO2-CO2 and FeO-MgO-SiO2-CO2 systems at lower mantle pressures where we investigate the stability of carbonate in oceanic crust, and test for decarbonation and diamond forming reactions involving carbonate and coexisiting free silica. We find that carbonate reacts with silica to form bridgmanite ± Ca-perovskite + CO2 at pressures in the range of ~50 to 70 GPa. These decarbonation reactions form an impenetrable barrier to subduction of carbonate into the deeper lower mantle, however, slabs may carry solid CO2 (Phase V) into the deeper lower mantle. We also identify reactions where carbonate or CO2 dissociate to form diamond plus oxygen. We suggest that the deep lower mantle may become enriched in carbon in the form of diamond over time due to subduction of carbonate and solid CO2 and its eventual dissociation to form diamond plus oxygen. Release of oxygen during diamond formation may also provide a mechanism for locally oxidizing the deep mantle.
DS201810-2352
2018
Marshall, E.W.Marshall, E.W., Lasiter, J.C., Barnes, J.D.On the (mis) behavior of water in the mantle: controls on nominally anhydrous mineral water content in mantle peridotites.Earth and Planetary Science Letters, Vol. 499, pp. 219-229.United States, Colorado Plateaumetasomatism

Abstract: In magmatic settings, water behaves as an incompatible species and should be depleted during melting and enriched during metasomatism. Previous studies have identified correlations between nominally anhydrous mineral (NAM) water content ([H2O]) and indices of metasomatism or melt extraction, seemingly confirming this behavior in the mantle. However in detail, these correlations are ambiguous and do not reflect robust controls on NAM [H2O]. We measured orthopyroxene (opx) and clinopyroxene (cpx) [H2O] in variably hydrated and metasomatized peridotite xenoliths from the Navajo volcanic field (NVF) that sample the Colorado Plateau subcontinental lithospheric mantle (SCLM), an endmember of SCLM hydration and metasomatism. These xenoliths span a wide range of pyroxene [H2O] (opx from 50 to 588 ppm wt. H2O; cpx from 38 to 581 ppm wt. H2O), but NAM [H2O] does not correlate with either indices of melt depletion or metasomatism. Growth of hydrous minerals suggests higher water activity than in anhydrous peridotites, and therefore hydrous-mineral-bearing xenoliths and anhydrous xenoliths should have different NAM [H2O] and water activities. However, when the two groups are compared no significant differences can be found in either NAM [H2O] or water activity. We propose that the high diffusivity of hydrogen in the mantle allows for equilibration of water activity in the mantle over sub-kilometer length scales over geologic time. Such diffusive equilibration reduces water activity variability and results in the blurring and destruction of correlations between NAM [H2O] and indices of metasomatism or melt extraction. As a result of diffusive equilibration of water, there is a large difference in the variability of concentration between NAM [H2O] (spanning ~2 orders of magnitude) and similarly incompatible elements such as Ce in the same peridotites (spanning ~4 orders of magnitude). This difference in behavior explains why H2O/Ce ratios in mantle peridotites are highly variable relative to those of basalts.
DS1994-1112
1994
Marshall, J.E.A.Marshall, J.E.A.The Falkland Islands: a key element in Gondwana paleogeographyTectonics, Vol. 13, No. 2, April pp. 499-514GlobalGondwana, Strtaigraphy
DS1994-1113
1994
Marshall, J.E.A.Marshall, J.E.A.The Falkland Islands: a key element in Gondwana paleogeographyTectonics, Vol. 13, No. 2, Apr. pp. 499-514.GlobalTectonics, Gondwana
DS1993-1151
1993
Marshall, J.R.Oberbeck, V.R., Marshall, J.R., Aggarwal, H.Impacts, tillites and the breakup of GondwanalandJournal of Geology, Vol. 101, No. 1, January, pp. 1-19Craters, Rifting
DS1993-1152
1993
Marshall, J.R.Oberbeck, V.R., Marshall, J.R., Aggarwal, H.Impacts, tillites and the breakup of GondwanalandJournal of Geology, Vol. 101, No. 1, January pp. 1-19.Tectonics, Rifting
DS1995-0248
1995
Marshall, L.G.Butler, R.F., Richards, D.R., Semepere, T., Marshall, L.G.Paleomagnetic determinations of vertical axis tectonic rotation from Late Cretaceous and Paleoene strataGeology, Vol. 23, No. 9, Sept. pp. 799-802BoliviaStratigraphy, Paleomagnetism
DS2000-0620
2000
Marshall, S.J.Marshall, S.J., Tarasov, L., Clarke, G., Peltier, R.Glaciological reconstruction of the Laurentide Ice Sheet: physical processes and modelling changes.Canadian Journal of Earth Sciences, Vol. 37, No.5, May pp.769-93.Ontario, CanadaGeomorphology
DS1995-1172
1995
Marshall, T.Marshall, T., Baxter-Brown, R.Basic principles of alluvial diamond explorationJournal of Geochemical Exploration, Vol. 52, pp. 277-292.Australia, South AfricaDiamond exploration, Alluvial, placers
DS200512-0688
2004
Marshall, T.Marshall, T.Rooikoppie gravels.Rough Diamond Review, No. 6, Sept.pp.Africa, South AfricaHistory
DS200712-0689
2007
Marshall, T.Marshall, T., Norton, G.The nature of the Ventersdorp alluvial diamond deposits.Diamonds in Kimberley Symposium & Trade Show, Bristow and De Wit held August 23-24, Kimberley, South Africa, GSSA Diamond Workshop CD slides 24Africa, South AfricaGeology, karst, gravels, Klipgat
DS201412-0551
2014
Marshall, T.Marshall, T., Lomberg, K., Other, A.N.The relevance of the (new, updated) SAMCODE to reporting of diamond exploration results, resources and reserves.GSSA Kimberley Diamond Symposium and Trade Show provisional programme, Sept. 11, title onlyGlobalSAMCODE
DS202006-0934
2020
Marshall, T.Marshall, T.GSSA Professional Affairs Portfolio - discussion April 29 and the need to be Professional!GSSA Presentation, https://www.youtube.com /watch?v=Hnwk3lPkMcMGlobalCSR - Professional Development
DS202104-0593
2021
Marshall, T.Marshall, T., Ward, J.D., de Wit, M.C.Alluvial diamond deposits across Africa - a travelogue.Geological Society of South Africa presentation, https://www.youtube.com/watch?v=1tsWuXo6fB4&t=23sAfrica, Lesotho, Cote d'Ivoire, Democratic Republic of Congo, Tanzania, Angola, South Africa, Ghana, Mauritania, Zimbabwe, Namibia, Central African Republic, Cameroon, Swaziland, Mali, Sierra Leone, Liberia, Guineaalluvials
DS1985-0415
1985
Marshall, T.R.Marshall, T.R., Pretorius, D.A.The Alluvial Diamond Fields of the Western Transvaal, Southafrica.Fourth International Kimberlite Conference, 2P. (abstract.) SUBMITTED.South Africa, TransvaalGeotectonics, Structure, Alluvial Placer Deposits
DS1986-0526
1986
Marshall, T.R.Marshall, T.R.The alluvial diamonds of the Western Transvaal South AfricaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 478-480South AfricaDiamond exploration
DS1986-0527
1986
Marshall, T.R.Marshall, T.R.The alluvial diamond fields of the Western TransvaalEconomic Geology Research Unit, Inf. Circular No. 188, 14pSouth AfricaPlacers
DS1987-0436
1987
Marshall, T.R.Marshall, T.R.The origin of the pans of the western Orange Free State- a morphotectonic study of the paleo-kimberley riverEconomic Geology Research Unit, Circular No. 196, 14pSouth AfricaGeomorphology, Tectonics
DS1989-0946
1989
Marshall, T.R.Marshall, T.R.The alluvial diamond fields of the western Transvaal,South Africa: origin of diamonds and gravelsGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 1204-1214South AfricaAlluvial/placers
DS1991-1061
1991
Marshall, T.R.Marshall, T.R.The Diamondiferous gravels of the southwestern Transvaal, South AfricaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 254-256South AfricaElluvial, alluvial, colluvial, placers, alluvial diamonds, Geomorphology
DS1994-1114
1994
Marshall, T.R.Marshall, T.R.The Diamondiferous gravels of the southwestern Transvaal, South AfricaProceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 187-201.South AfricaAlluvials, Placers -diamonds
DS2000-0221
2000
Marshall, T.R.De Wit, M.C.J., Marshall, T.R., Partridge, T.C.Fluvial deposits and drainage evolutionIn: The Cenozoic of Southern Africa, pp. 55-72.South AfricaGeomorphology - alluvials, tectonics, gravels
DS201012-0474
2009
Marshall, T.R.Marshall, T.R., Norton, G.A.The nature of the alluvial diamond deposits of the Ventersdorp district, northwest province, South Africa.South African Journal of Geology, Vol. 112, 2, pp. 109-124.Africa, South AfricaAlluvials
DS201212-0444
2012
Marshall, T.R.Marshall, T.R.Evaluation and valuation of alluvial diamond deposits.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, South AfricaDeposit - alluvial, placer
DS201312-0576
2013
Marshall, T.R.Marshall, T.R.Resource estimation and valuation of alluvial diamond deposits.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 281-288.TechnologyReserves - DCF
DS201412-0552
2013
Marshall, T.R.Marshall, T.R.Resource estimation and valuation of alluvial diamond deposits.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 281-288.Global, AfricaEconomics - alluvials
DS201609-1716
2016
Marshall, T.R.De Wit, M., Bhebhe, Z., Davidson, J., Haggerty, S.E., Hundt, P., Jacob, J., Lynn, M., Marshall, T.R., Skinner, C., Smithson, K., Stiefenhofer, J., Robert, M., Revitt, A., Spaggiari, R., Ward, J.Overview of diamonds resources in Africa.Episodes, Vol. 9, 2, pp. 198-238.AfricaDiamond resources - overview

Abstract: From the discovery of diamonds in South Africa in 1866 until the end of 2013, Africa is estimated to have produced almost 3.2 Bct out of a total global production of 5.03 Bct, or 63.6% of all diamonds that have ever been mined. In 2013 African countries ranked 2nd (Botswana), 3rd (DRC), 6th (Zimbabwe), 7th (Angola), 8th (South Africa), and 9th (Namibia), in terms of carat production and 1st (Botswana), 4th (Namibia), 5th (Angola), 6th (South Africa), 7th (Zimbabwe), and 9th (DRC), in terms of value of the diamonds produced. In 2013 Africa produced 70.6 Mct out of a global total of 130.5 Mct or 54.1%, which was valued at US$ 8.7 billion representing 61.5% of the global value of US$ 14.1 billion.
DS202106-0955
2020
Marshall, T.R.Marshall, T.R.Evaluation of secondary diamond ( and gemstone) deposits according to SAMREC code.saimm.co.za, 6p. PdfAfrica, South Africaalluvials

Abstract: Alluvial diamond and other gemstone deposits have, typically, been exploited by small artisanal operations with little or no geological control. Over the last decade, however, alluvial deposits have become more interesting to larger (often listed), mid-tier companies wishing to benefit from the higher incomes generated by high-quality stones. The difficulties associated with evaluation and valuation of such alluvial diamond/gemstone deposits are widely known but, regrettably, often not widely understood - leading to several misconceptions over what can and cannot be expected from such deposits. Fortunately, there is a reasonably well-established body of knowledge on alluvial diamonds that has resulted in accepted industry-standard practices of how to evaluate these deposits. The 2016 version of the SAMREC Code includes several sections specific to the requirements of secondary diamond and gemstone deposits, both alluvial and marine. Consequently, it is possible to define Diamond/Gemstone Resources in accordance with the major international Committee for Mineral Reserves International Reporting Standards (CRIRSCO) type codes. This paper outlines some of the requirements and some of the pitfalls that need to be appreciated while estimating Diamond/Gemstone Resources and/or Reserves on such deposits.
DS1860-0445
1884
Marshall, W.P.Marshall, W.P.Notes on the Great Kimberley MineMidland Naturalist (birmingham), Vol. 7, PP. 93-98.Africa, South AfricaDiamond mining
DS1995-1178
1995
Marshintsev, V.Mathez, E.A., Fogel, R.A., Hutcheon, I.D., Marshintsev, V.Carbon isotopic composition and origin of SIC from kimberlites of Russia.Geochimica et Cosmochimica Acta, Vol. 59, No. 4, Feb. pp. 781-792.Russia, YakutiaGeochronology
DS1960-0270
1962
Marshintsev, V.K.Lutts, B.G., Marshintsev, V.K.A Xenolith of Garnet Pyroxenite from the Mir Kimberlite PipeAkad. Nauk Sssr Sib. Div. Yakut., No. L4, PP. 307-3LL.RussiaBlank
DS1960-0863
1967
Marshintsev, V.K.Marshintsev, V.K., Shcelchkova, S.G., Zol'nikov, G.V., Voskres.New Dat a on Moissanite from the Yakutian KimberlitesGeologii i Geofiziki, No. 12, PP. 22-31.RussiaBlank
DS1960-0868
1967
Marshintsev, V.K.Nikishov, K.N., Marshintsev, V.K.Intrusive Carbonatites and Their Relation To kimberlites of Yakutia.Perm:, RussiaKimberlite
DS1970-0131
1970
Marshintsev, V.K.Marshintsev, V.K.Discovery of Baddelyite in Kimberlitic Rocks of YakutiaIn: Geology, Petrography And Mineralogy of Magmatic Formatio, PP. 247-253.RussiaBlank
DS1970-0132
1970
Marshintsev, V.K.Marshintsev, V.K., Sukneva, L.S.Scandium in Minerals and Rocks of the Yakutian Kimberlite Bodies.Geochemistry International, Vol. 7, PP. 1048-1050.RussiaBlank
DS1970-0575
1972
Marshintsev, V.K.Nikischov, K.N., Kovalsky, V.V., Marshintsev, V.K.The Alkalic-ultrabasic Rocks ( Alnoites, Kimberlites and Carbonatites) in the Northeast of the Siberian PlatformInternational Geological Congress 24TH. (MONTREAL), MINERALOGY SECTION, PP. 5L-56.RussiaBlank
DS1982-0399
1982
Marshintsev, V.K.Marshintsev, V.K.Inclusions of Cubic Silicon Carbide in Moissanite from Kimberlitic Rocks, a New Occurrence in Nature #2United States Geological Survey (USGS) TRANSLATION., No. 547, 6P.RussiaCrystallography, Inclusion
DS1982-0400
1982
Marshintsev, V.K.Marshintsev, V.K.Inclusions of Cubic Silicon Carbide in Moissanite from Kimberlite Rocks- New Occurrence in Nature #1United States Geological Survey (USGS) TRANSLATION SERIES, No. 547.RussiaBlank
DS1982-0401
1982
Marshintsev, V.K.Marshintsev, V.K., et al.Inclusions of Cubic Silicon Carbide in Moissanite from Kimberlite Rocks - a New Find in Nature.Doklady Academy of Sciences Nauk SSSR., Vol. 262, No. 1, PP. 204-206.RussiaKimberlite
DS1983-0434
1983
Marshintsev, V.K.Marshintsev, V.K., Zayakina, N.V., Leskova, N.V.New Find of Cubic Silicon Carbide, As Inclusions in Moissanite from Kimberlitic Rocks.Doklady Academy of Science USSR, Earth Science Section., Vol. 262, No. 1-6, PP. 163-166.RussiaMineralogy
DS1984-0136
1984
Marshintsev, V.K.Barashkov, Y.P., Marshintsev, V.K.Tendency toward ilmenite crystallization in kimberlites fromYakutia.(Russian)Doklady Academy of Sciences Akademy Nauk SSSR (Russian), Vol. 278, No. 5, pp. 1210-1213RussiaPetrology, Ilmenite
DS1984-0443
1984
Marshintsev, V.K.Lapin, A.V., Marshintsev, V.K.Carbonatites and Kimberlitic Carbonatites.(russian)Geol. Rudn. Mestorozh., (RUS), Vol. 26, No.3, pp. 28-42RussiaCarbonatite, Genesis
DS1984-0487
1984
Marshintsev, V.K.Marshintsev, V.K., Nikishova, L.V., Gotovtsev, V.V.Serpentine Filling the Needle Channels in Olivine of the Udachnaia Vostochnaia Pipe.Doklady Academy of Sciences AKAD. NAUK. SSSR., Vol. 277, No. 3, PP. 697-700.RussiaBlank
DS1986-0099
1986
Marshintsev, V.K.Brahkov, Yu.P., Marshintsev, V.K.Crystallization trends of ilmenite from kimberlites of YakutiaDoklady Academy of Science USSR, Earth Science Section, Vol. 278, No. 1-6, April, pp. 158-161RussiaMineralogy
DS1986-0528
1986
Marshintsev, V.K.Marshintsev, V.K.Vertical heterogeneity of kimberlite bodies of Yakutia.(Russian)Nauka Siberskoe Otd. Novobirsk*(in Russian), 240pRussiaKimberlite, Petrology
DS1986-0529
1986
Marshintsev, V.K.Marshintsev, V.K., Nikishova, L.V., Gotovtsev, V.V.Serpentine filling needle shaped channels in olivine from the Udachnaya east pipeDoklady Academy of Science USSR, Earth Science Section, Vol. 277, March pp. 170-174RussiaUdachnaya, Mineralogy
DS1988-0442
1988
Marshintsev, V.K.Marshintsev, V.K., Barashkov, I.P.Pipe associated veins as a criterion in search for kimberlitepipes.(Russian)Doklady Academy of Sciences Akad. Nauk SSSR, (Russian), Vol. 298, No. 2, pp. 438-441RussiaBlank
DS1989-0073
1989
Marshintsev, V.K.Barahkov, Yu.P., Marshintsev, V.K., Pankov, V.Yu.Solid inclusions in pyrope-almandine garnets from the kimberlite veins associated with the pipeUdachnaya, Yakutia.(Russian)Mineral. Zhurnal. UKR, (Russian), Vol. 11, No. 3, pp. 19-30RussiaGarnets -analyses-inclusions, Deposit -Udachnaya
DS1989-0074
1989
Marshintsev, V.K.Barashkov, Yu.P., Marshintsev, V.K., Pankov, V. Yu.Solid inclusions in pyrope-almandine garnets from kimberlite veins associated with the Udachnaya pipe.(Russian)Mineral. Zhurn., (Russian), Vol. 11, No. 3, pp. 19-30RussiaGarnet inclusions
DS1989-0947
1989
Marshintsev, V.K.Marshintsev, V.K., Barashkov, Yu.P.Identitification of kimberlite pipes from the presence of kimberlite veins around theM.Doklady Academy of Science USSR, Earth Science Section, Vol. 298, No. 1-6, April pp. 119-121RussiaDykes, Kimberlite
DS1989-0948
1989
Marshintsev, V.K.Marshintsev, V.K., Barashkov, Yu.P.Identification of kimberlite pipes from the presence Of kimberlite veins around theM.Doklady Academy of Science USSR, Earth Science Section, Vol. 298, No. 1-6, pp. 119-121RussiaKimberlite veins, Exploration
DS1990-0990
1990
Marshintsev, V.K.Marshintsev, V.K.Natural shallow carbides in kimberlites of YakutiaInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 814-815RussiaKimberlites, Silicon carbides
DS1990-0991
1990
Marshintsev, V.K.Marshintsev, V.K.Nature of silicon carbide in kimberlite rocks of Yakutia.(Russian)Mineral. Zhurn., (Russian), Vol. 12, No. 3, pp. 17-26RussiaSilicon carbide, Kimberlites
DS1992-1005
1992
Marshintsev, V.K.Marshintsev, V.K.Thallium in natural media of Yakut diamond bearing Province. (Russian)Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 324, No. 5, pp. 1128-1130.Russia, YakutiaGeochemistry, ThalliuM.
DS1994-1115
1994
Marshintsev, V.K.Marshintsev, V.K.Primary kimberlite magmaInternational Symposium Upper Mantle, Aug. 14-19, 1994, Extended abstracts p. 30.RussiaMagma, Kimberlite magma
DS1997-0059
1997
Marshintsev, V.K.Babushkina, S.A., Marshintsev, V.K.Composition of spinel, ilmenite, garnet and diopside inclusions in phlogopite macrocrysts Mir kimberlite.Russian Geology and Geophysics, Vol. 38, No. 2, pp. 467-480.Russia, YakutiaPetrography, Deposit - Mir
DS1984-0135
1984
Marshintsov, V.K.Barashko, I.P., Marshintsov, V.K.The Crystallization Trend of Ilmenite in Yakutian KimberliteDoklady Academy of Sciences AKAD. NAUK SSSR., Vol. 278, No. 5, PP. 1210-1213.RussiaGenesis
DS1986-0050
1986
Marshontsev, V.K.Barashkov, Yu.P., Marshontsev, V.K.Crystallization trends of ilmentite from kimberlites of YakutiaDoklady Academy of Science USSR, Earth Science Section, Vol. 278, No. 1-6, pp. 158-161RussiaMir, Udachnaya, Crystallography
DS201912-2788
2020
Marske, J.Hauri, E.H., Cottrell, E., Kelley, K.A., Tucker, J.M., Shimizu, K., Le Voyer, M., Marske, J., Sall, A.E.Carbon in the convecting mantle. IN: Deep carbon: past to present, Orcutt, Daniel, Dasgupta eds., pp. 237-275.Mantlecarbon

Abstract: This chapter provides a summary of the flux of carbon through various oceanic volcanic centers such as mid-ocean ridges and intraplate settings, as well as what these fluxes indicate about the carbon content of the mantle. By reviewing methods used to measure the carbon geochemistry of basalts and then to estimate fluxes, the chapter provides insight into how mantle melting and melt extraction processes are estimated. The chapter discusses how the flux of carbon compares with other incompatible trace elements and gases. From there, the chapter discusses whether the budget of carbon in the ocean mantle can be explained by primordial carbon or whether carbon recycling is required to balance the budget.
DS1860-0704
1891
Marsters, V.F.Kemp, J.F., Marsters, V.F.The Trap Dikes in the Lake Champlain Valley and the Neighbouring Adirondacks.New York Academy of Sciences Transactions, Vol. 11, PP. 13-23.United States, New YorkGeology, Related Rocks
DS1860-0801
1893
Marsters, V.F.Kemp, J.F., Marsters, V.F.The Trap Dikes of the Lake Champlain RegionUnited States Geological Survey (USGS) Bulletin., No. 107, PP. 11-62.United States, New York, VermontGeology, Related Rocks
DS1860-0900
1895
Marsters, V.F.Marsters, V.F.Camptonite and other Intrusives of Lake MemphremagogAmerican GEOLOGIST., Vol. 16, PP. 25-39.Canada, Quebec, United States, VermontRelated Rocks
DS1860-0901
1895
Marsters, V.F.Marsters, V.F.Comptonite and other Intrusives of Lake MemphremagogAmerican Geologist., Vol. 16, PP. 25-39.United States, New YorkPetrology
DS1985-0416
1985
Marston, K.Marston, K.Where Diamonds Are a Gull's Best Friend #2Indiaqua., No. 40, 1985/1, PP. 13-14.Southwest Africa, NamibiaHistory
DS200812-0400
2008
Mart, J.Geyer, A., Mart, J.The new worldwide collapse caldera database (CCDB): a tool for studying and understanding caldera processes.Journal of Volcanology and Geothermal Research, Vol. 175, 3. August 10, pp. 334-354.MantleCalderas
DS201212-0168
2012
Mart, J.Doronzo, D.M., Mart, J., Sulpizio, R., Dellino, P.Aerodynamics of stratovolcanoes during multiphase processes.Journal of Geophysical Research,, Vol. 117, B1, B01207.MantleVolcanoes
DS200912-0088
2008
Mart, R.W.Burke, K., Khan, S.D., Mart, R.W.Grenville Province and Monteregian carbonatite and nepheline syenite distribution related to rifting, collision and plume passage.Geology, Vol. 36, 12, Dec. pp. 983-986.Canada, QuebecCarbonatite
DS202012-2249
2020
Martayan, G.Schmetzer, K., Martayan, G., Blake, A.R.History of the Chivor emerald mine, part 2 ( 1924-1970): between insolvency and viability.Gems & Gemology, Vol. 56, 2, summer pp. 230-257. pdfSouth America, Columbiadeposit - Chivor

Abstract: The history of the Chivor emerald mine in Colombia is a saga with countless twists and turns, involving parties from across the globe. Indigenous people initially exploited the property, followed by the Spanish in the sixteenth and seventeenth centuries, before abandonment set in for 200 years. The mine was rediscovered by Francisco Restrepo in the 1880s, and ownership over the ensuing decades passed through several Colombian owners and eventually to an American company, the Colombian Emerald Syndicate, Ltd., with an intervening but unsuccessful attempt by a German group organized by Fritz Klein to take control. With the Colombian Emerald Syndicate succumbing to bankruptcy in 1923, the property was sold and then transferred in 1924 to another American firm, the Colombia Emerald Development Corporation. Under the new ownership, stock market speculation played a far more prominent role in the story than actual mining. Nonetheless, periods of more productive mining operations did take place under managers Peter W. Rainier and Russell W. Anderton. Yet these were not enough to prevent the company, renamed Chivor Emerald Mines, Inc. in 1933, from entering insolvency in 1952 and being placed into receivership. Leadership by Willis Frederick Bronkie enabled the firm to regain independence in 1970 and shortly thereafter to be sold in a series of transactions, with Chivor gradually being returned to Colombian interests.
DS202102-0219
2020
Martayan, G.Schmetzer, K., Martayan, G., Ortiz, J.G.History of the Chivor emerald mine, Part 1 ( 1880-1925): from rediscovery to early production. Part 2 listed previouslyGems & Gemology , Vol. 56, 1, pp. 66-109.South America, Colombiaemerald

Abstract: The history of the Chivor emerald mine in Colombia is rife with legend and adventure. The tale traces from early exploitation by indigenous people, to work by the Spanish in the sixteenth and seventeenth centuries, to 200 years of abandonment and jungle overgrowth. The story then picks up with rediscovery near the turn of the twentieth century by the Colombian mining engineer Francisco Restrepo using clues from a historical manuscript. Still the saga continued, with repeated shortages of investment funds driving multiple ownership changes and little progress toward mining the largely inaccessible deposit. The German gem merchant Fritz Klein, in cooperation with Restrepo, pursued limited mining activities with a small number of workers for a few months prior to the outbreak of World War I. After the war, the American company Colombian Emerald Syndicate, Ltd., took ownership, and mining operations resumed under the new leadership. Ownership changed yet again in the 1920s, followed by multiple cycles of expanding and shrinking mining activity, interrupted by completely unproductive periods.
DS1999-0491
1999
MartelMoorhead, J., Beaumier, M., Lefevbre, Bernier, MartelKimberlites, lineaments et rifts crustaux au Quebec #1Quebec Ministere des Ressources naturelles, (in French), MB99-35, approx. 60p.Quebec, Ungava, LabradorKimberlite, Tectonics, structure, fields, lineaments
DS2000-0682
2000
MartelMoorhead, J., Beaumier, M., Lefebvre, Bernier, MartelKimberlites, lineaments et rifts crustaux au Quebec #2Quebec Department of Mines, Report, 69p.QuebecKimberlites, tectonics, lineaments, rifts, Area - overviews
DS202103-0396
2021
Martel, E.Neil, B.J.C., Gibson, H.D., Pehrsson, S.J., Martel, E., Thiessen, E.J., Crowley, J.L.Provenance, stratigraphic and precise depositional age constraints for an outlier of the 1.9 to 1.8 Ga Nonacho Group, Rae craton, Northwest Territories, Canada.Precambrian Research, Vol. 352, 105999, 15p. PdfCanada, Northwest Territoriesgeochronology

Abstract: The Nonacho Group comprises six formations of continental clastic rocks that were deposited between 1.91 and 1.83?Ga. The Nonacho Group is part of a broader assemblage of conglomerate and sandstone that was deposited atop the Rae craton in response to the amalgamation of Laurentia and supercontinent Nuna, but the details of its tectonic setting are contentious. This paper documents an outlier of Nonacho Group rocks ~50?km east of the main Nonacho basin. Field observations and LA-ICPMS (laser ablation inductively coupled plasma mass spectrometry) U-Pb detrital zircon geochronology are integrated with previous studies of the main basin to better understand the group’s depositional history, provenance and tectonic setting. The lithology and detrital zircon age spectra of the outlier allow for its correlation to the upper two formations of the Nonacho Group. CA-ID-TIMS (chemical abrasion isotope dilution thermal ionization mass spectrometry) analyses of two fragments of the youngest detrital zircon provide a maximum depositional age of 1901.0?±?0.9?Ma. A felsic volcanic cobble dated at ca. 2.38?Ga provides evidence of volcanism during the Arrowsmith orogeny. Detrital zircon dates recovered from the outlier (ca. 3.4-3.0, 2.7, 2.5-2.3 and 2.0-1.9?Ga) are consistent with derivation from topography of the Taltson and/or Thelon orogens on the western margin of the Rae craton. Taltson-Thelon (2.0 to 1.9?Ga) aged detritus is only abundant in the upper two formations of the Nonacho Group, marking a change in provenance from the lower formations. This change in provenance may have coincided with a period of renewed uplift and the unroofing of Taltson-Thelon plutons. The detrital zircon provenance and depositional age of the Nonacho Group is consistent with models that link its deposition to the Taltson and/or Thelon orogens. However, tectonism associated with the 1.9 to 1.8?Ga Snowbird and Trans-Hudson orogens to the east could also have affected basin formation or the change in provenance from the lower to upper Nonacho Group. This study highlights the importance of CA-ID-TIMS in establishing accurate and precise maximum depositional ages for sedimentary successions.
DS202103-0402
2021
Martel, E.Regis, D., Pehrsson, S., Martel, E., Thiessen, E., Peterson, T., Kellett, D.Post - 1.9 Ga evolution of the south Rae craton ( Northwest Territories), Canada: a paleoproterozoic orogenic collapse system.Precambrian Research, Vol. 355, 106105, 29p. PdfCanada, Northwest Territoriessunduction

Abstract: The Trans-Hudson Orogen (THO), formed from the convergence between the Superior craton and the composite Churchill Upper Plate (CUP), is one of the best-preserved examples of a collisional orogen in the Paleoproterozoic. Similar to modern collision systems such as the Himalayan orogen, it is characterized by a composite upper plate in which terrane accretion established a continental plateau that was tectonically and magmatically active for >100 myr. Our study presents new petrological and geochronological data for four samples collected in three lithotectonic domains of the south Rae craton (one of the CUP terranes). The results presented here allow us to re-define the previously proposed extent of THO reworking in the CUP and afford the opportunity to study and compare the evolution of various fragments that illustrate differing levels of a collapsed plateau in the CUP hinterland. The new data indicate that the south Rae craton locally preserves evidence for burial at 1.855-1.84 Ga with peak metamorphic conditions at approximately 790 °C and 9.5-12.5 kbar followed by rapid cooling and decompression melting (P < 6 kbar) at ca. 1.835-1.826 Ga. These results, which provide important and so far missing Pressure-Temperature-time (P-T-t) constraints on the evolution of the south Rae craton in the Northwest Territories at Trans-Hudson time, coupled with existing regional geochronological and geochemical data, are used to propose an updated model for the post-1.9 Ga THO collision and extensional collapse. Our results reveal that: i) initial thickening in the upper plate started at Snowbird time (ca. 1.94 Ga), then continued via Sask collision (with high-grade metamorphism recorded in the south Rae craton, ca. 1.85 Ga), and ended with Superior collision (ca. 1.83 Ga); ii) the extent of the THO structural and metamorphic overprint in the SW CUP is much broader across strike than previously recognized, and iii) T-t data in the south Rae are indicative of relatively fast cooling rates (8-25 °C/Ma) compared to other known Precambrian orogens. We suggest that the Paleoproterozoic THO represents the first record of a major ‘modern-style’ orogenic plateau collapse in Earth’s history.
DS1993-0136
1993
Martel, J-J.Borduas, B., Martel, J-J.The Le Tac Township kimberlite discoveryQuebec Exploration Conference summaries held September 15-1th. Val d'Or, pp. 13-16QuebecLe Tac Township
DS2002-0753
2002
Martel, S.J.Ito, G., Martel, S.J.Focusing of magma in the upper mantle through dike interactionJournal of Geophysical Research, Oct. 29, 10.1029/2001JB000251.MantleMagmatism
DS2002-0754
2002
Martel, S.J.Ito, G., Martel, S.J.Focusing of magma in the upper mantle through dike interactionJournal of Geophysical Research, Vol. 107, 10, ECV 6 DOI 10.1029/2001JB000251MantleMagmatism - not specific to diamonds
DS2000-0621
2000
Martelat, J.E.Martelat, J.E., Lardeaux, J.M., Rakotondrazafy, R.Strain pattern and late Precambrian deformation history in southern MadagascarPrecambrian Research, Vol. 102, No. 1-2, July 1, pp. 1-20.MadagascarTectonics
DS202007-1162
2020
Martelat, J-E.Martelat, J-E., Cardon, H., Lardeaux, J-M., Nicollet, C., Schulmann, K., Pili, E.Geophysical evidence for large scale mullion type structures at the mantle crust interface in southern Madagascar: implications for Neoproterozoic orogeny.International Journal of Earth Science, Vol. 109, 4, pp. 1487-1500.Africa, Madagascartectonics

Abstract: This study uses gravimetric data integrated with recent seismic data published on south Madagascar to investigate geometry of crust-mantle interface. The regional tectonic framework of Madagascar is characterised by anastomosing network of up to 15-km-wide, 600-km-long and north-oriented high-strain zones, which originated during Neoproterozoic convergence. The studied Bouguer anomalies obtained from the International Gravimetric Bureau were high-pass filtered to emphasise short-wavelength gravimetric variations (shorter than 200 km). The Pan-African high-strain zones coincide with the positive gravimetric anomalies suggesting a link with deep seated high-density material. Considering the present-day thickness of the crust (35 km) and its seismic velocity record, the gravimetric anomalies can be visualised as narrow vertical tabular bodies located at the base of the Moho. Modelling further confirmed that such narrow vertical bodies could be stable over geologic time scale since these structures are relatively small (10 to 30 km wide). The vertical tabular bodies possibly reflect material transfer such as vertical motion of sub-crustal weak and possibly partially molten mantle along vertical deformation zones. It is proposed that these structures were initiated by folding of weak mantle-crust interface characterised by low-viscosity contrast between weak mantle and stronger granulitized lower crust during bulk pure shear-dominated horizontal shortening. It is proposed that the cuspate-lobate "mullion-type" geometry mimics rheological inversions of mafic and felsic rocks and shape of folds of variable scale observed in southern Madagascar. The formation of such mega-mullion structures is possibly an expression of "crème brulée" rheological model, where the deformation of the lithosphere is governed by stronger granulitic lower crust and weaker partially molten and/or hydrated mantle.
DS201709-1984
2017
Martelet, J-E.Feneyrol, J., Giuliani, G., Demaiffe, D., Ohenstetter, D., Fallick, A.E., Dubessy, J., Martelet, J-E., Rakotondrazafy, A.F.M., Omito, E., Ichangi, D., Nyamai, C., Wamunyu, W.Age and origin of the tsavorite and tanzanite mineralozing fluids in the Neoproterozoic Mozambique metamorphic belt.The Canadian Mineralogist, Vol. 55, pp. 763-786.Africa, Kenya, Tanzania, Madagascartanzanite

Abstract: The genetic model previously proposed for tsavorite- (and tanzanite-) bearing mineralization hosted in the Neoproterozoic Metamorphic Mozambique Belt (stretching from Kenya through Tanzania to Madagascar) is refined on the basis of new Sm-Nd age determinations and detailed Sr-O-S isotope and fluid-inclusion studies. The deposits are hosted within meta-sedimentary series composed of quartzites, graphitic gneisses, calc-silicate rocks intercalated with meta-evaporites, and marbles. Tsavorite occurs either in nodules (also called “boudins”) oriented parallel to the metamorphic foliation in all of the deposits in the metamorphic belt or in quartz veins and lenses located at the hinges of anticlinal folds (Lelatema fold belt and Ruangwa deposits, Tanzania). Gem tanzanite occurs in pockets and lenses in the Lelatema fold belt of northern Tanzania. The Sm-Nd isotopic data for tsavorites and tanzanites hosted in quartz veins and lenses from Merelani demonstrate that they formed at 600 Ma, during the retrograde metamorphic episode associated with the East African Orogeny. The tsavorites hosted in nodules do not provide reliable ages: their sedimentary protoliths had heterogeneous compositions and their Sm-Nd system was not completely rehomogenized, even at the local scale, by the fluid-absent metamorphic recrystallization. The initial 87Sr/86Sr isotopic ratios of calcite from marble and tanzanites from Merelani fit with the strontium isotopic composition of Neoproterozoic marine carbonates. Seawater sediment deposition in the Mozambique Ocean took place around 720 Ma. The quartz-zoisite O-isotopic thermometer indicates a temperature of formation for zoisite between 385 and 448 °C. The sulfur isotopic composition of pyrite (between –7.8 and –1.3‰ V-CDT) associated with tsavorite in the Lelatema fold belt deposits suggests the contribution of reduced marine sulfate. The sulfur in pyrite in the marbles was likely derived from bacterial sulfate reduction which produced H2S. Fluid inclusion data from tsavorite and tanzanite samples from the Merelani mine indicate the presence of a dominant H2S-S8±(CH4)±(N2)±(H2O)-bearing fluid. In the deposits in Kenya and Madagascar, the replacement of sulfate by tsavorite in the nodules and the boron isotopic composition of tourmaline associated with tsavorite are strong arguments in favor of the participation of evaporites in garnet formation.
DS201812-2851
2018
Marten, B.E.Moss, S., Marten, B.E., Felgate, M., Smith, C.B., Chimuka, L., Matchan, E.L., Phillips, D.Murowa deposit: Geology, structure and radiometric age determination of the Murowa kimberlites, Zimbabwe.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 379-402.Africa, Zimbabwedeposit - Murowa
DS2001-0152
2001
Martens, H.Butler, H., Martens, H.Northern latitudes mining reclamation workshop... abstract29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p.9.Northwest TerritoriesMine reclamation - mine tailings, Deposit - Ekati
DS1920-0160
1923
Martens, J.H.C.Martens, J.H.C.Study of Igneous Rocks of Ithaca, New York and VicinityGeological Society of America (GSA) Bulletin., Vol. 34, No. 1, P. 99.United States, Appalachia, New YorkGeology, Related Rocks
DS1920-0161
1923
Martens, J.H.C.Martens, J.H.C.A Study of the Basic Dikes of the Ithaca RegionMsc. Thesis, Cornell University, 101P.United States, Appalachia, New YorkPetrology
DS1920-0188
1924
Martens, J.H.C.Martens, J.H.C.Igneous Rocks of Ithaca, New York and VicinityGeological Society of America (GSA) Bulletin., Vol. 35, PP. 305-320.United States, Appalachia, New YorkGeology, Related Rocks
DS2003-0878
2003
Martens, P.Martens, P., Rotmans, J., De Groot, D.Biodiversity: luxury or necessityGlobal Environmental Change, Part A, Vol. 13, 2, pp. 75-81.GlobalBiodiversity - Not specific to diamonds
DS200412-1231
2003
Martens, P.Martens, P., Rotmans, J., De Groot, D.Biodiversity: luxury or necessity.Global Environmental Change, Part A, Vol. 13, 2, pp. 75-81.GlobalBiodiversity - Not specific to diamonds
DS201502-0077
2014
Martens, U.Martens, U., Restrepo, J.J., Ordonez-Carmona, O., Correa-Martinez, A.M.The Tahami and Anaconda terranes of the Colombian Andes: missing links between South American and Mexican Gondwana margins.Journal of Geology, Vol. 122, Sept. pp. 507-530.South America, MexicoTectonics
DS2000-0563
2000
Marti, J.Legros, F., Kelfoun, K., Marti, J.The influence of conduit geometry on the dynamics of caldera forming eruptions.Earth and Planetary Science Letters, Vol. 179, No. 1, June 15, pp. 53-62.Globalvolcanism - calderas, PhreatomagmatisM.
DS201806-1235
2018
Marti, J.Marti, J., Groppelli, G., Brum da Silveira, A.Volcanic stratigraphy: a review.Journal of Volcanology and Geothermal Research, Vol. 357, pp. 68-91.Mantlevolcanism

Abstract: Volcanic stratigraphy is a fundamental component of geological mapping in volcanic areas as it yields the basic criteria and essential data for identifying the spatial and temporal relationships between volcanic products and intra/inter-eruptive processes (earth-surface, tectonic and climatic), which in turn provides greater understanding of the geological evolution of a region. Establishing precise stratigraphic relationships in volcanic successions is not only essential for understanding the past behaviour of volcanoes and for predicting how they might behave in the future, but is also critical for establishing guidelines for exploring economic and energy resources associated with volcanic systems or for reconstructing the evolution of sedimentary basins in which volcanism has played a significant role. Like classical stratigraphy, volcanic stratigraphy should also be defined using a systematic methodology that can provide an organised and comprehensive description of the temporal and spatial evolution of volcanic terrain. This review explores different methods employed in studies of volcanic stratigraphy, examines four case studies that use differing stratigraphic approaches, and recommends methods for using systematic volcanic stratigraphy based on the application of the concepts of traditional stratigraphy but adapted to the needs of volcanological environment.
DS201212-0574
2012
Martignago, F.Princivalle, F., Martignago, F., Nestola, F., Dal Negro, A.Kinetics of cation ordering in synthetic Mg(Al,Fe3+2O4 spinels.European Journal of Mineralogy, Vol. 24, 4, pp. 633-643.TechnologySpinel
DS1989-0638
1989
Martignole, J.Higgins, M.D., Feininger, T., Martignole, J., Nantel, S.The Sept Iles layered mafic intrusion and the anorthosite complex of Riviere PentecoteGeological Association of Canada (GAC) Field Trip, May 17-21, NoQuebecXenoliths
DS1989-1279
1989
Martignole, J.Rivers, T., Martignole, J., Gower, C.F., Davidson, A.New tectonic divisions of the Grenville Province southeastCanadianshieldTectonics, Vol. 8, No. 1, February pp. 63-84OntarioOrogeny -Grenville, Tectonics
DS1992-1006
1992
Martignole, J.Martignole, J.Exhumation of high grade terranes - a reviewCanadian Journal of Earth Sciences, Vol. 29, pp. 737-745.Globalmetamorphism, Magmatic arcs
DS1994-0222
1994
Martignole, J.Brunet, S., Martignole, J.Nepheline bearing rocks of the reservoir Cabonga area, Grenville ProvinceQuebec: a possible carbonatitic origin.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p. posterQuebecCarbonatite, Cabonga
DS1995-0220
1995
Martignole, J.Brunet, S., Martignole, J.Gneiss et pegmatites a nepheline du reservoir Cabonga, parc de la VerendryeQuebec Department of Mines, MB 95-04, 35p.QuebecNepheline syenite
DS1996-0894
1996
Martignole, J.Martignole, J., Calvert, A.J.Crustal scale shortening and extension across the Grenville Province Of western Quebec.Tectonics, Vol. 15, No. 2, Apr. pp. 376-86.Quebec, LabradorGeophysics - seismics
DS1998-0947
1998
Martignole, J.Martignole, J., Friedman, R.Geochronological constraints on the last stages on terrane assembly in the central part of Grenville ProvPrecambrian Research, Vol. 92, No. 2, Oct.l, pp. 145-64OntarioGeochronology - tectonics, Terrane - Grenville Province
DS2000-0622
2000
Martignole, J.Martignole, J., Calvert, A.J., Friedman, R., ReynoldsCrustal evolution along a seismic section across the Grenville Province, western Quebec.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.291-306.QuebecGeophysics - seismics, Tectonics
DS2002-1315
2002
MartikhaevRazvozzhaeva, E.A., Prokofev, Spiridonov, MartikhaevPrecious metals and carbonaceous substance in ores of the Sukhoi Log deposit, Eastern Siberia, Russia.Geology of Ore Deposits, Vol.44,2,pp. 103-110.RussiaGold, carbon, metallogeny, Deposit - Sukhoi Log
DS2001-0720
2001
MartinMajaule, T., Hanson, Key, Singletary, Martin, BowringThe Magondi belt in northeast Botswana: regional relations and new geochronological dat a from Sua PanJournal of African Earth Sciences, Vol. 32, No. 2, pp. 257-67.BotswanaOrogeny, Geochronology - mentions diamond area
DS1992-0122
1992
Martin, A.Bickel, M.J., Martin, A., Nisbet, E.G., Orpen, J.L., et al.The geology of the Belingwe greenstone belt, ZimbabweA.a. Balkema, approx. $ 70.00ZimbabweBook -Greenstone belt, Crustal evolution
DS1994-0159
1994
Martin, A.Bickle, M.J., Nisbet, G.G., Martin, A.Archean greenstone belts are not oceanic crustJournal of Geology, Vol. 102, No. 2, March pp. 121-138ZimbabweGreenstone belts, Crust -oceanic
DS1998-0649
1998
Martin, A.Hunter, M.A., Bickle, M.J., Nisbet, E.G., Martin, A.Continental extensional setting for the Archean Belingwe Greenstone Belt, ZimbabweGeology, Vol. 26, No. 10, Oct. pp. 883-6ZimbabweGreenstone belt - Belingwe, Tectonics
DS1910-0203
1911
Martin, A.H.Martin, A.H.Mining for Precious Stones in CaliforniaMining and Scientific Press, Vol. 63, MARCH 23RD. PP. 316-317.United States, California, West CoastBlank
DS1981-0285
1981
Martin, A.K.Martin, A.K., Hartnady, C.J.H., Goodlad, S.W.Pre-drift Fit of the Natal Valley and the Falkland PlateauCape Town: Tech. Report Mar. Geosci. Unit, Geological Survey South, No. 12, PP. 30-44.South Africa, South AmericaTectonics
DS1987-0437
1987
Martin, A.K.Martin, A.K.Plate reorganizations around Southern Africa, hot spot sand SOURCE[ TectonophysicsTectonophysics, Vol. 142, No. 2-4, November 1, pp. 309-316South AfricaBlank
DS201112-0646
2011
Martin, A.M.Martin, A.M., Hammouda, T.Role of iron and 6 GPa a potential mechanism for diamond formation during subduction.European Journal of Mineralogy, Vol. 23, 1, pp. 5-16.MantleDiamond genesis
DS201112-0647
2011
Martin, A.M.Martin, A.M., Hammouda, T.Role of iron and reducing conditions on the stability of dolomite + coesite between 4.25 and 6 GPa - a potential mechanism for diamond formation during subductionEuropean Journal of Mineralogy, Vol. 23, 1, pp. 5-16.MantleSubduction, diamond genesis
DS201212-0445
2012
Martin, A.M.Martin, A.M., Laporte, D., Koga, K.T., Kawamoto, T., Hammouda, T.Experimental study of the stability of a dolomite + coesite assemblage in contact with peridotite: implications for sediment-mantle interaction and diamond formation during subduction.Journal of Petrology, Vol. 53, 2, pp. 391-417.TechnologyUHP, diamond genesis
DS201212-0446
2012
Martin, A.M.Martin, A.M., Laporte, D., Koga, K.T., Kawamoto, T., Hammouda, T.Experimental stidy of the stability of a dolomite + coesite assembalge in contact with peridotite: implications for sediment-mantle interaction and diamond formation during subduction.Journal of Petrology, Vol. 53, 2, pp. 391-417.MantleSubduction
DS201312-0577
2013
Martin, A.M.Martin, A.M., Righter, K.Melting of clinopyroxene + magnesite in iron-bearing planetary mantles and implications for the Earth and Mars.Contributions to Mineralogy and Petrology, Vol. 166, 4, pp. 1067-1098.MantleCarbonatite, kamafugite
DS201510-1785
2015
Martin, A.P.Martin, A.P., Price, R.C., Cooper, A.F., McCammon, C.A.Petrogenesis of the rifted southern Victoria Land lithospheric mantle, Antarctica, inferred from petrography, geochemistry, thermobarometry and oxybarometry of peridotite and pyroxenite xenoliths from the Mount Morning eruptive centre.Journal of Petrology, Vol. 56, 1, pp. 193-226.AntarcticaMelting, subduction

Abstract: The lithospheric mantle beneath West Antarctica has been characterized using petrology, whole-rock and mineral major element geochemistry, whole-rock trace element chemistry and Mössbauer spectroscopy data obtained on a suite of peridotite (lherzolite and harzburgite) and pyroxenite xenoliths from the Mount Morning eruptive centre, Southern Victoria Land. The timing of pyroxenite formation in Victoria Land overlaps with subduction of the Palaeo-Pacific plate beneath the Gondwana margin and pyroxenite is likely to have formed when fluids derived from, or modified by, melting of the subducting, eclogitic, oceanic crustal plate percolated through peridotite of the lithospheric mantle. Subsequent melting of lithospheric pyroxenite veins similar to those represented in the Mount Morning xenolith suite has contributed to the enriched trace element (and isotope) signatures seen in Cenozoic volcanic rocks from Mount Morning, elsewhere in Victoria Land and Zealandia. In general, the harzburgite xenoliths reflect between 20 and 30% melt depletion. Their depleted element budgets are consistent with Archaean cratonization ages and they have mantle-normalized trace element patterns comparable with typical subcontinental lithospheric mantle. The spinel lherzolite mineral data suggest a similar amount of depletion to that recorded in the harzburgites (20-30%), whereas plagioclase lherzolite mineral data suggest <15% melt depletion. The lherzolite (spinel and plagioclase) xenolith whole-rocks have compositions indicating <20% melt depletion, consistent with Proterozoic to Phanerozoic cratonization ages, and have mantle-normalized trace element patterns comparable with typical depleted mid-ocean ridge mantle. All peridotite xenoliths have undergone a number of melt-rock reaction events. Melting took place mainly in the spinel peridotite stability field, but one plagioclase peridotite group containing high-sodium clinopyroxenes is best modelled by melting in the garnet field. Median oxygen fugacity estimates based on Mössbauer spectroscopy measurements of spinel and pyroxene for spinel-facies conditions in the rifted Antarctic lithosphere are -0·6 ?log fO2 at Mount Morning and –1·0 ± 0·1 (1s) ?log fO2 for all of Victoria Land, relative to the fayalite-magnetite-quartz buffer. These values are in good agreement with a calculated global median value of -0·9 ± 0·1 (1s) ?log fO2 for mantle spinel-facies rocks from continental rift systems.
DS200912-0474
2009
Martin, C.Martin, C.How to sell. A tale of shady jewellers honesty.... a salesperson is a human advertisement. Review in the National Post July 18, by M. Medley.Book Review, Publ. Farrar, Strauss and Giroux,United StatesBook review - just for interest!
DS1982-0403
1982
Martin, C.A.Martin, C.A.Diamonds: a Visit to Premier, the Prince of Diamond PipesChamber Mines Journal, Vol. 24, No. 4, PP. 35-43.South AfricaMining, Diamonds, Recovery, Geology
DS1984-0488
1984
Martin, C.A.Martin, C.A.Diamonds; Zimbabwe Engineer, 1984Zimbabwe Engineer., Vol. 22, No. 6, NOVEMBER PP. 514-515.South AfricaPremier, Mining Methods, Tailings, Diamond Morphology
DS1989-0949
1989
Martin, C.E.Martin, C.E.Rhenium- Osmium (Re-Os) isotopic investigations of the Stillwater Complex, MontanaEarth and Planetary Science Letters, Vol. 93, No. 3/4 July pp. 336-344. Database # 18092MontanaStillwater Complex, PlatinuM.
DS1991-1062
1991
Martin, C.E.Martin, C.E.Osmium isotopic characteristics of mantle derived rocksGeochimica et Cosmochimica Acta, Vol. 55, pp. 1421-1434GlobalMantle, Geochronology
DS1991-1063
1991
Martin, C.E.Martin, C.E., Esser, B.K., Turekian, K.K.Rhenium- Osmium (Re-Os) isotopic constraints on the formation of mantle and crustalAustralian Journal of Earth Sciences, Vol. 38, December pp. 569-576MantleCrustal reservoirs, Geochronology
DS201012-0120
2010
Martin, C.E.Cooper, A.F., Boztug, D., Palin, J.M., Martin, C.E., Numata, M.Petrology and petrogenesis of carbonatitic rocks in syenites from central Anatolia, Turkey.Contributions to Mineralogy and Petrology, in press available, 18p.Europe, TurkeyCarbonatite
DS201112-0206
2011
Martin, C.E.Cooper, A.F., Boztug, D., Palin, J.M., Martin, C.E., Numata, M.Petrology and petrogenesis of carbonatitic rocks in syenites from central Anatolia, Turkey.Contributions to Mineralogy and Petrology, Vol. 161, 5, pp. 811-828.Europe, TurkeyCarbonatite
DS201507-0322
2015
Martin, C.E.Liu, J., Scott, J.M., Martin, C.E., Pearson, D.G.The longevity of Archean mantle residues in the convecting upper mantle and their role in young continent formation.Earth and Planetary Science Letters, Vol. 424, pp. 109-118.MantleConvection
DS1987-0438
1987
Martin, D.Martin, D., Griffiths, R.W., Campbell, I.H.Compositional and thermal convection in magma chambersContributions to Mineralogy and Petrology, Vol. 96, No. 4, pp. 465-475GlobalXenoliths
DS1990-0992
1990
Martin, D.Martin, D.Crystal settling and in situ crystallization in aqueous solutions and magmachambersEarth and Planetary Science Letters, Vol. 96, pp. 336-348GlobalMagma chambers, Experimental petrology
DS1998-0948
1998
Martin, D. McB.Martin, D. McB., Clendenin, C.W., Krapez, B., McNaughtonTectonic and geochronological constraints on late Archean and Paleoproterozoic stratigraphic correlationJournal of the Geological Society of London, Vol. 155, pp. 311-22.South Africa, AustraliaCraton - Kaapvaal, Pilbara, Geochronology - SHRIMP
DS1986-0530
1986
Martin, D.C.Martin, D.C., Steenkamp, N.S.L., Lill, . J.W.Application of a statistical analysis technique for design of high rock slopes at Palabora mine, South AfricaInstitute of Mining and Metallurgy (IMM) Special Publishing Mining Latin America, pp. 241-255South AfricaCarbonatite, Palabora
DS1990-0993
1990
Martin, D.C.Martin, D.C., Zavodni, Z.M.Use of percussion drilling information for pit slope designAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, No. 90-128, 9pGlobalMining, Drilling -pit slope design
DS201612-2346
2016
Martin, D.McB.Wingate, M.T.D., Martin, D.McB.Updated digital map of mafic dyke swarms and large igneous provinces in Western Australia.Acta Geologica Sinica, Vol. 90, July abstract p. 14-15.AustraliaDykes
DS1900-0342
1905
Martin, D.S.Martin, D.S.Diamonds at Syracuse. #1Onondaga Academy of Science Proceedings, Oct. 24TH. MEETING.United States, Appalachia, New York, South AfricaDiamond Occurrences
DS200812-0716
2008
Martin, E.Martin, E., Martin, H., Sigmarsson, O.Could Iceland be a modern analogue for the Earth's early continental crust?Terra Nova, Vol. 20, no. 6, pp. 463-468.Europe, IcelandMantle
DS202010-1871
2020
Martin, E.Rebeiro, B.V., Cawood, P.A., Faleiros, F.M., Mulder, J.A., Martin, E., Finch, M.A., Raveggi, M., Teixeira, W., Cordani, U.G., Pavan, M.A long lived active margin revealed by zircon U-Pb-Hf data from the Rio Apa terrane (Brazil): new insights into the Paleoproterozoic evolution of the Amazonian craton.Precambrian Research, 57p. PdfSouth America, Brazilcraton

Abstract: We present the first regional in-situ zircon U-Pb-Hf isotopic data from metaigneous and metasedimentary rocks from the Paleo- to Mesoproterozoic Rio Apa Terrane (RAT), a crustal fragment outcropping in the central-western Brazil and north-eastern Paraguay. These new ages and Hf isotopic data delineate three magmatic events, which record the construction of the temporally and isotopically distinct Western and Eastern Terranes of the RAT. The Western Terrane comprises the 2100-1940 Ma Porto Murtinho Complex and the 1900-1840 Ma Amoguijá Belt, which both define a crustal reworking array in eHfT-time space evolving from a precursor source with Hf TDM age of ca. 2700 Ma. The 1800-1720 Ma Caracol Belt constitutes the Eastern Terrane and yields suprachondritic eHfT signatures up to +7.1, indicating significant juvenile input. The metasedimentary Amolar Group and Rio Naitaca Formation in the Western Terrane have maximum depositional ages of 1850-1800 Ma and subchondritic eHfT signatures down to -5.7, similar to the underlying basement of the Amoguijá Belt. In the Eastern Terrane, the Alto Tererê Formation has a maximum depositional age of 1750 Ma and mostly suprachondritic eHfT signatures, similar to magmatic rocks of the underlying Caracol Belt. Together, the new igneous and detrital zircon age and Hf isotopic data record a temporal and spatial transition from 2100 to 1840 Ma crustal reworking in the west to more juvenile magmatism at 1800-1720 Ma in the east. This transition is interpreted to reflect convergent margin magmatism associated with periods of subduction zone advance and retreat in an accretionary orogenic setting. Comparison of the eHfT-time signature of the RAT with the Amazonian Craton suggest penecontemporaneous development, with the Western and Eastern Terranes of the RAT being correlative with the Ventuari-Tapajós and Rio Negro-Juruena Province of the Amazonian Craton, respectively. Our new data also reveal that the eHfT signatures of the RAT are distinct from the Maz terrane, which refutes the MARA Block hypothesis.
DS202102-0205
2020
Martin, E.L.Martin, E.L., Spencer, C.J., Collins, W.J., Thomas, R.J., Macey, P.H., Roberts, N.M.W.The core of Rodinia formed by the juxtaposition of opposed retreating and advancing accretionary orogens.Earth-Science Reviews, Vol. 211, doi.org/10.1016 /j.earscirev.2020 .103413 17p. Pdf Globalcratons

Abstract: Long-lived (800?Ma) Paleo- to Mesoproterozoic accretionary orogens on the margins of Laurentia, Baltica, Amazonia, and Kalahari collided to form the core of the supercontinent, Rodinia. Accretionary orogens in Laurentia and Baltica record predominately radiogenic zircon eHf(t) and whole-rock Pb isotopic compositions, short crustal residence times (ca. 0.5?Ga), and the development of arc-backarc complexes. The accretionary orogenic record of Laurentia and Baltica is consistent with a retreating accretionary orogen and analogous to the Phanerozoic western Pacific orogenic system. In contrast, the Mesoproterozoic orogens of Amazon and Kalahari cratons record unradiogenic zircon eHf(t) values, ca. 0.8?Ga crustal residence times, and more ancient whole-rock Pb isotopic signatures. The accretionary orogenic record of Amazonia and Kalahari indicates the preferential incorporation of cratonic material in continental arcs of advancing accretionary orogens comparable to the Phanerozoic eastern Pacific orogenic system. Based on similarities in the geodynamic evolution of the Phanerozoic circum-Pacific orogens peripheral to Gondwana/Pangea, we suggest that the Mesoproterozoic accretionary orogens formed as peripheral subduction zones along the margin of the supercontinent Nuna (ca. 1.8-1.6?Ga). The eventual collapse of this peripheral subduction zone onto itself and closure of the external ocean around Nuna to form Rodinia is equivalent to the projected future collapse of the circum-Pacific subduction system and juxtaposition of Australia-Asia with South America. The juxtaposition of advancing and retreating accretionary orogens at the core of the supercontinent Rodinia demonstrates that supercontinent assembly can occur by the closure of external oceans and indicates that future closure of the Pacific Ocean is plausible.
DS1989-0950
1989
Martin, F.Martin, F., Merigoux, H., Zecchini, P.Reflectance infrared spectroscopy in gemologyGems and Gemology, Vol. 25, No. 4, Winter pp. 226-231GlobalSpectroscopy, Mineral species -general
DS1984-0482
1984
Martin, G.Marot, A., Capdevila, R., Leveque, B., Gruau, G., Martin, G., Cha.Le Synclinorium du Sud de Guyane Francaise: une Ceinture Deroches Vertes D'age Proterozoic Inferieur.Annual DES SCIENCES DE la TERRE, 10TH. SESSION HELD BORDEAU, South America, GuyanaBlank
DS1950-0285
1956
Martin, H.Martin, H.Wenn Es Krieg Gibt, Gehen Wir in die WuesteStuttgart: Union Deutsche Verlag, 244P.South Africa, Namibia, Southwest AfricaBiography, Kimberley
DS1960-0574
1965
Martin, H.Martin, H.The Precambrian Geology of Southwest Africa and NamaqualandPrecambr. Res. Unit University Cape Town., 159P.Southwest Africa, Namibia, South AfricaGeology, Kimberley
DS1970-0680
1973
Martin, H.Ferguson, J., Martin, H., Nicolaysen, L.O., Danchin, R.Gross Brukkaros: a Kimberlite Carbonatite Volcano1st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 107-110.Southwest Africa, NamibiaGeology
DS1975-0076
1975
Martin, H.Ferguson, J., Martin, H., Nicholson, L.O., Danchin, K.Gross Brukkaros, a Kimberlite Carbonatite VolcanoPhysics and Chemistry of the Earth., Vol. 9, PP. 219-234.Southwest Africa, NamibiaGibeon, Melilitite, Geology, Geochronology
DS1981-0286
1981
Martin, H.Martin, H.The Large BrukkarosJournal of SWA Scientific Society, Vol. 36-37, pp. 7-10Southwest Africa, NamibiaBlank
DS1984-0323
1984
Martin, H.Gruau, G., Martin, H., Leveque, B., Capdevila, R., Marot, A.Rubidium-strontium and Samarium-neodymium (sm-nd) Geochronology of Lower proterozoic Granite Greenstone Terrains in French Guiana, South America.B.r.g.m., IN PRESSSouth America, French GuianaBlank
DS1984-0489
1984
Martin, H.Martin, H.Uber die Herkunft der Diamanten an der Kueste von S.w.a. Namibia und Namaqualand.Mitteilungen Aus Dem Geologisch Palaeontologischen Institut, No. 56, PP. 31-44.South Africa, Southwest Africa, Namibia, NamaqualandBlank
DS1984-0490
1984
Martin, H.Martin, H.Uber die Herkunft der Diamanten an der Kuste von. S.W.A./Namibia undNamaqualand.(in German)Mitt. Geol. Palaont. Institute University of Hamburg., (in German), Vol. 56, pp. 31-44Southwest AfricaGenesis
DS1991-1064
1991
Martin, H.Martin, H., Sabate, P., Peucat, J.J., Cunha, J.C.An early Archean crustal segment (3.4 Ga) -the Sete Voltas Massif (Bahia, Brasil).(in French)Comptes Rendus de la'Academie des Sciences Serie II, Vol. 313, No. 5, August 29, pp. 531-538BrazilArchean, Craton
DS1993-0974
1993
Martin, H.Martin, H.The mechanisms of petrogenesis of the Archean continental crust -comparison with modern processesLithos, Vol. 30, No. 3-4, September pp. 373-388MantleCrust, Petrogenesis
DS1996-0159
1996
Martin, H.Bourgopis, J., Martin, H., Lagabrielle, Y., et al.Subduction erosion related to spreading ridge subduction: Titao peninsula(Chile triple junction)Geology, Vol. 24, No. 8, August pp. 723-726ChileSubduction, Tectonics
DS1997-0739
1997
Martin, H.Martin, H., Peucat, J.J., Cunha, J.C.Crustal evolution in the early Archean of South America: example of the Sete Voltas MassifPrecambrian Research, Vol. 82, No. 1-2, March 1, pp. 35-62Brazil, BahiaArchean, Geotectonics
DS2002-0997
2002
Martin, H.Martin, H., Moyen, J-F.Secular changes in tonalite trondhjemite granodiorite composition as markers of the progressive cooling earthGeology, Vol. 30,4,Apr.pp.319-22.MantleSlab melting, Archean
DS200712-0227
2007
Martin, H.De Souza, Z.S., Martin, H., Peucat, J-J., Jardim De Sa, E.F., De Frietas Macedo, M.H.Calc alkaline magmatism at the Archean Proterozoic transition: the Caico Complex basement ( NE Brazil).Journal of Petrology, Vol. 48, 11, pp. 2149-2185.South America, Brazil, SeridoMagmatism
DS200812-0681
2008
Martin, H.Lobach Zhuchenko, S.B., Rollinson, H., Chekulaev, V.P., Savatenkov, V.M., Kovalenko, A.V., Martin, H., Guseva, N.S., Arestova, N.A.Petrology of Late Archean, highly potassic, sanuktoid pluton from the Baltic Shield: insights into Late Archean mantle metasomatism.Journal of Petrology, Vol. 49, 3, pp. 393-420.Europe, Baltic shieldMetasomatism
DS200812-0716
2008
Martin, H.Martin, E., Martin, H., Sigmarsson, O.Could Iceland be a modern analogue for the Earth's early continental crust?Terra Nova, Vol. 20, no. 6, pp. 463-468.Europe, IcelandMantle
DS201012-0611
2010
Martin, H.Rapp, R.P., Norman, M.D., Laporte, D., Yaxley, G.M., Martin, H., Foley, S.F.Continent formation in the Archean and chemical evolution of the cratonic lithosphere: melt rock reaction experiments at 3-4 GPa and petrogenesisJournal of Petrology, Vol. 51, 6, pp. 1237-1266.MantleSanukitoids
DS1998-0949
1998
Martin, J.Martin, J., Edgley, G.J.Environmental management systems: a guide for planning, development andimplementationGovernment Institutes, $ 75.00GlobalBook - ad, Environment
DS200412-0105
2003
Martin, J.Barton, J.M., Barnett, W.P., Barton, E.S., Barnett, M., Doorgapershad, A., Twiggs, C., Klemd, B.R., Martin, J.The geology of the areas surrounding the Venetia kimberlite pipes, Limpopo belt, South Africa: a complex interplay of Nappe tectSouth African Journal of Geology, Vol. 106, 2-3, pp. 109-128.Africa, South AfricaDeposit - Venetia, tectonics
DS200412-0470
2003
Martin, J.Doorgapershad, A., Barnett, M., Twiggs, C., Martin, J., Millonig, L., Zenglein, R.Procedures used to produce a digitized geological mapping database of the area around the Venetia kimberlite pipes, Limpopo BeltSouth African Journal of Geology, Vol. 106, 2-3, pp. 103-108.Africa, South AfricaDeposit - Venetia, mapping
DS200412-1015
2003
Martin, J.Klemd, R., Martin, J., Schmidt, A., Barton, J.M.P-T path constraints from calc silicate metapelitic rocks east of the Venetia kimberlite pipes, Central Zone, Limpopo Belt, SoutSouth African Journal of Geology, Vol. 106, 2-3, pp. 129-148.Africa, South AfricaDeposit - Venetia, metamorphism, geochronology
DS1975-0781
1978
Martin, J.A.Kisvarsanyi, G., Martin, J.A.Tectonic and Metallogenic Significance of Major Structural Lineaments in the Mid-continent.Geological Society of America (GSA), Vol. 10, No. 1, P. 8. (abstract.).GlobalMid-continent
DS1975-1126
1979
Martin, J.E.Martin, J.E.Ashton Joint Venture- Second Quarter 1979 Progress Report. Attachment to Letter from Jem to Ajaj.In House Unpubl. Report., 3P.Australia, Western AustraliaGrades, Tonnages, Sampling, Stones, Carats
DS201412-0380
2014
Martin, L.Huang, J-X., Griffin, W.L., Greau, Y., Pearson, N.J., O'Reilly, S.Y., Cliff, J., Martin, L.Unmasking xenolithic eclogites: progressive metasomatism of a key Roberts Victor sample.Chemical Geology, Vol. 364, pp. 55-65.Africa, South AfricaDeposit - Roberts Victor
DS201709-1999
2017
Martin, L.Huang, J-X., Xiong, Q., Griffin, W.L., Martin, L., Toledo, V., O'Reilly, S.Y.Moissanite in volcanic systems: super reduced conditions in the mantle.Goldschmidt Conference, abstract 1p.Mantlemoissanite

Abstract: Moissanite (SiC) occurs in mantle and mantle-generated rocks from different tectonic settings. SiC is stable only at low oxygen fugacity (ƒO2) ?IW. Israeli SiC is assiociated with corundum, Fe globules, native V and other phases in Cretaceous pyroclastic rocks from Mt Carmel and associated alluvial deposits[1]. The SiC grains contain inclusions of Si metal, FeSi2, FeTiSi2, FeAlSi2 and CaSi2+xSi2-x, which were liquids before being trapped during SiC crystallization. SiC has been found included in corundum, associated with Fe-Ti silicides, connecting the formation of SiC, reduced melts in corundum and conrundum itself. All grains are of the 6H polytype. d13C ranges from - 32.1 to -24.5‰ and d30Si from -0.68 to +1.42‰. These SiC grains are one product of the interaction of basaltic magma and mantle methane in a volcanic plumbing system. SiC crystallized from metallic melts that became immiscible during the reduction of the magma. Its low d13C may reflect Rayleigh fractionation under reduced conditions; the variation in Si isotopes may reflect fractionation between SiC and immiscible metallic melts. SiC samples from the Udachnaya and Mir kimberlite pipes contain inclusions of Si metal, FeSi2, FeSi, FeTiSi2, Si(N,O). The SiC has d13C ranging from -28.5 to -24.8‰, and d30Si from -1.72 to +1.42‰. SiC from harzburgites, chromitites and pyroxenites of the Tibetan Zedang ophiolites have inclusions of Si metal and unmixed Fe-Ni-Ti-Si alloy. Their d13C ranges from -30.6 to -24.7‰ and d30Si from -0.85 to +1.26‰. SiC samples from these different settings show very similar characteristics, implying that they may be formed in similar mantle conditions, where the flux of mantle methane gradually reduces magmas and interacts with them to produce different reduced phases at different stages.
DS201810-2372
2018
Martin, L.Rielli A., Tomkins, A.G., Nebel, O., Raveggi, M., Jeon, H., Martin, L., Laure, A., Janaina, N.Sulfur isotope and PGE systematics of metasomatised mantle wedge.Earth and Planetary Science Letters, Vol. 497, 1, pp. 181-192.Mantlemetasomatism

Abstract: At convergent margins fluids liberated from subducting slabs metasomatise the overlying mantle wedge, enriching it in volatiles, incompatible elements and possibly ore-forming metals. Despite the genetic link between this process, the genesis of arc magmas, and formation of porphyry Cu-Au deposits, there is currently little understanding of the behaviour of chalcophile and siderophile elements during subduction-related mantle metasomatism. In this study, we report sulfur isotopic compositions and PGE concentrations of sulfides in a suite of garnet peridotites from the Western Gneiss Region of Norway, sampling mantle wedge from ~100 to ~250 km depth. Sulfides hosted in metasomatised samples have deviated from typical mantle values, ranging between -10.0 and +5.4‰, indicating derivation of sulfur from subducted crust. Sulfides in pervasively metasomatised samples have atypical PGE signatures, with strong enrichment in Os and Ru relative to Ir, whereas channelised fluid flow produced sulfides extremely enriched in Pd, up to 700 times the concentration found in non-metasomatised samples. These signatures are reconcilable with a high oxidation state of the metasomatising agents and demonstrate that subduction can recycle chalcophile and siderophile elements into and within the mantle, along with sulfur. We further show that because the solubility of Os and Ru in fluids is redox sensitive, and Pd is more soluble than the I-PGE, ratios such as Os/Ir, Ru/Ir plotted against Pd/Ir can be used to trace the metasomatic oxidation of mantle samples, mantle-derived magmas and porphyry Cu±Au deposits. This geochemical insight is used to show that Au-rich porphyry Cu deposits are derived from more oxidised mantle wedge than Au-poor porphyry deposits.
DS202102-0237
2021
Martin, L.Yakmchuck, C., Kirkland, C.L., Cavosie, A.J., Szilas, K., Hollis, J., Gardinerm N.J., Waterton, P., Steenfelt, A., Martin, L.Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland.Earth and Planetary Science Letters, Vol. 557, doi.org/10.1016/ j.epsl.2020.116730 9p. PdfEurope, Greenlandmeteorite

Abstract: Large meteorite impacts have a profound effect on the Earth's geosphere, atmosphere, hydrosphere and biosphere. It is widely accepted that the early Earth was subject to intense bombardment from 4.5 to 3.8 Ga, yet evidence for subsequent bolide impacts during the Archean Eon (4.0 to 2.5 Ga) is sparse. However, understanding the timing and magnitude of these early events is important, as they may have triggered significant change points to global geochemical cycles. The Maniitsoq region of southern West Greenland has been proposed to record a ~3.0 Ga meteorite impact, which, if confirmed, would be the oldest and only known impact structure to have survived from the Archean. Such an ancient structure would provide the first insight into the style, setting, and possible environmental effects of impact bombardment continuing into the late Archean. Here, using field mapping, geochronology, isotope geochemistry, and electron backscatter diffraction mapping of 5,587 zircon grains from the Maniitsoq region (rock and fluvial sediment samples), we test the hypothesis that the Maniitsoq structure represents Earth's earliest known impact structure. Our comprehensive survey shows that previously proposed impact-related geological features, ranging from microscopic structures at the mineral scale to macroscopic structures at the terrane scale, as well as the age and geochemistry of the rocks in the Maniitsoq region, can be explained through endogenic (non-impact) processes. Despite the higher impact flux, intact craters from the Archean Eon remain elusive on Earth.
DS201905-1033
2019
Martin, L.A.J.Giuliani, A., Martin, L.A.J., Soltys,A., Griffin, W.L.Mantle like oxygen isotopes in kimberlites determined by in situ SIMS analyses of zoned olivine.Geochimica et Cosmochimica Acta, in press available, 19p.Africa, South Africa, Canada, South America, Brazildeposit - Lac de Gras, Paranaiba

Abstract: Kimberlites are the deepest melts produced on Earth that are erupted at the surface and can therefore provide unique insights into the composition and evolution of the mantle. Radiogenic isotopes provide ambiguous evidence for the occurrence of recycled crustal material in kimberlite sources. Oxygen isotopes can fractionate significantly only in the shallow crust, and thus represent a powerful tracer of subducted material in the sources of kimberlite. To constrain the oxygen isotope composition of kimberlite melts, we have examined olivine grains in eleven Cretaceous to Eocene archetypal kimberlites from southern Africa, Lac de Gras (Canada) and Alto Paranaiba (Brazil), which exhibit radiogenic isotope evidence for recycled crustal material in their sources including highly radiogenic Pb isotopes and Nd-Hf isotope compositions deviating below the mantle array. Olivine grains are commonly zoned between a mantle-derived xenocrystic core and one or more magmatic overgrowths, i.e. occasional internal zones, ubiquitous rims and rare rinds (moving outward from the core). The oxygen isotope composition of different olivine zones was determined in situ within separated olivine grains by secondary ion mass spectrometry (SIMS) after point selection using back-scattered electron (BSE) images combined with major and minor element analyses. With the exception of a few cores, the d18O values of different olivine zones do not deviate from typical mantle olivine values of 5.18?±?0.28‰ (Mattey et al., 1994). There are no correlations between oxygen isotopes and major/minor element compositions for internal zones and rims from individual localities or in the entire dataset. This indicates that the oxygen isotope composition of kimberlite melts is not affected by melt differentiation to the point of olivine rim crystallisation. However, olivine rinds from the Koala kimberlite (Canada) display an inverse correlation between d18O and Mn-Ca concentrations, with d18O values extending below the mantle range, which is probably due to carbonate fractionation, CO2 degassing and/or assimilation of serpentine-rich material after kimberlite emplacement in the upper crust. The mantle-like d18O composition of olivine internal zones and rims suggests that assimilation of mantle material and liberation of a CO2-rich phase during ascent in the mantle do not significantly modify the original d18O signature of kimberlite melts. Modelling of oxygen isotope fractionation shows that up to 15 wt% of CO2 can be lost by kimberlites en route to the upper crust. Our results combined with mass balance calculations indicate that only a limited amount (<5-10 wt%) of recycled crustal material could occur in the source of kimberlites from southern Africa, Lac de Gras and Alto Paranaiba, or that the recycled material had an oxygen isotope composition similar to the mantle.
DS202107-1094
2021
Martin, L.A.J.Consuma, G., Aulbach, S., Braga, R., Martin, L.A.J., Tropper, P., Gerdes, A., Fiorentini, M.L.Multi-stage sulfur and carbon mobility in fossil continental subduction zones: new insights from carbonate-bearing orogenic peridotites. *** Not specific to diamondsGeochimica et Cosmochimica Acta, Vol. 306, pp. 143-170. pdfEurope, Italysubduction

Abstract: The volatile transfer in subduction zones and the role of sulfate as a vector for the mobilization of oxidized components from down-going slabs remain hotly debated issues. Orogenic spinel and garnet peridotite lenses from the Ulten Zone (Eastern Alps, Italy), exhumed as part of felsic metamorphic terranes in continental collision zones, bear witness to mass transfer processes in these pivotal environments. In this study, we carried out a multi-method investigation of mantle sulfides coexisting with four generations of carbonates, indicating coupled sulfur and carbon mobility throughout the peridotites’ metamorphic evolution as part of the Variscan subduction architecture. Detailed petrography, bulk rock measurements, in situ chemical and geochemical analyses of sulfides as well as Sr isotope analyses of associated clinopyroxene and amphibole are combined with the aim to constrain the origin, nature and effect of multiple C-O-H-S-bearing fluids and melts the peridotites interacted with. The first, pre-peak, metasomatic pulse (Stage 1) is represented by an H2S-CO2-bearing melt from the subduction-modified hot mantle wedge, which formed a pyroxenite layer hosting matrix pentlandite with d34S of +2.77‰. Matrix carbonates occasionally occur in the coarse-grained peridotite under eclogite-facies conditions (Stage 2), with heavier d34S (up to +3.43‰), radiogenic Sr (87Sr/86Srclinopyroxene > 0.7052) and elevated Pb abundances. These are ascribed to interaction with isotopically heavy melts carrying recycled crustal component, permissive of, but not requiring, involvement of oxidized S species. Conversely, isotopically lighter matrix pentlandite (d34S = -1.62 to +0.67‰), and radiogenic Sr in amphibole (87Sr/86Sr = 0.7056) and associated dolomite (published data) from fine-grained garnet-amphibole peridotites may point to involvement of H2S-CO2-bearing crustal fluids, which variably equilibrated with the mantle before interacting with the peridotites. The post-peak Stage 3 marks the entrapment of peridotites into a tectonic mélange. Here, kelyphitization of garnet is catalyzed by further ingress of a S-bearing fluid (d34S = -0.38‰), while carbonate veining with occasional sulfides bear witness to channelized fluid flow. Sulfide and amphibole grains in retrogressed spinel peridotites reveal the highest contents of fluid-mobile elements (As, Sb) and 87Sr/86Sramphibole up to 0.7074, suggesting late interactions with isotopically heavy crustal fluids at high fluid-rock ratios. Textural observations indicate that, during Stage 4, serpentinization of peridotites at low ƒS2 played an active role not only in CO2 release by conversion of dolomite to calcite + brucite intergrowths, but also in local removal of 32S during the final exhumation stage. Late channelized sulfur remobilization is evidenced by the serpentine + magnetite (±millerite ± calcite) vein carrying > 300 ppm S. Overall, the relatively narrow range of sulfur isotope composition (d34S = -1.62 to +3.76‰) is indicative of limited interaction with isotopically heavy crustal liquids, and points to a subordinate role of subduction-derived sulfate throughout the extended fluid(melt)/rock evolution of the Ulten Zone peridotites, first in the mantle wedge and then as part of a tectonic mélange.
DS201212-0447
2012
Martin, L.H.J.Martin, L.H.J., Schmidt, M.W., Mattsson, H.B., Ulmer, P., Hametner, K., Gunther, D.Element partitioning between immiscible carbonatite-kamafugite melts with application to the Italian ultrapotassic suite.Chemical Geology, Vol. 320-321 pp. 96-112.Europe, ItalyCarbonatite
DS201312-0579
2013
Martin, L.H.J.Martin, L.H.J., Schmidt, M.W., Mattsson, H.B., Guenther, D.Element partitioning between immiscible carbonatite and silicate melts for dry and H2O bearing systems at 1-3 Gpa.Journal of Petrology, Vol. 54, pp. 2301-2338.MantleCarbonatite
DS201112-0408
2011
Martin, M.Hammouda, T., Andrault, D., Koga, K., Katsura, T., Martin, M.Ordering in double carbonates and implications for processes at subduction.Contributions to Mineralogy and Petrology, Vol. 161, 3, pp. 439-450.MantleSubduction
DS201811-2617
2018
Martin, M.Walter, B.F., Parsapoor, A., Braunger, S., Marks, M.A.W., Wenzel, T., Martin, M., Markl, G.Pyrochlore as a monitor for magmatic and hydrothermal processes in carbonatites from the Kaiserstuhl volcanic complex ( SW Germany).Chemical Geology, Vol. 498, pp. 1-16.Europe, Germanycarbonatite

Abstract: Pyrochlore from the Kaiserstuhl volcanic complex (SW Germany) shows textural and compositional differences between various coarse-grained calcite-carbonatite bodies (Badberg, Degenmatt, Haselschacher Buck, Orberg) and extrusive carbonatites (Henkenberg, Kirchberg). Oscillatory-zoned F-rich pyrochlore with up to 69?wt% Nb2O5 is common in all coarse-grained calcite-carbonatite bodies and probably formed during magmatic conditions. However, only in some of the samples from the Badberg, partly resorbed U- and Ta-enriched pyrochlore cores with up to 22?wt% UO2 and 9?wt% Ta2O5 have been identified, which are interpreted as being inherited from underlying nosean syenites. Pyrochlore data from a drill core penetrating the Badberg indicate increasing contents of REE, U, and Ta with depth, while Nb, F and Na contents decrease. This may reflect the combined effects of fractional crystallization and assimilation (AFC) or indicates a multi-stage emplacement of the carbonatitic magma. Patchy-zoned ceriopyrochlore and REE- and Th-enriched pyrochlore with up to 19?wt% total REE2O3 and 6.5?wt% ThO2 is largely restricted to samples from the Orberg and probably formed during hydrothermal conditions. This can be related to the relatively evolved character of the Orberg carbonatites, based on their relatively high whole-rock Nb/Ta and Zr/Hf mass ratios. This study demonstrates that the textural and compositional variation of pyrochlore in carbonatites is a powerful tool to distinguish magmatic, hydrothermal and weathering processes in carbonatitic systems.
DS1994-1116
1994
Martin, M.D.Martin, M.D., Hyyppa, R.R.The case for periodic outsider operational reviewsAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, Meeting held Albuquerque Feb. 14-17th, No. 94-167, 14pGlobalMining, Philosophy
DS1987-0135
1987
Martin, M.M.Davies, G., Thomaz, M.F., Nazare, M.H., Martin, M.M., Shaw, D.Radiative decay time of luminescence from the vacancy in diamondJournal of Phys. C. Solid State Phys, Vol. 20, No.1, Jan. 10, pp. L13-L17GlobalCrystallography
DS1990-1498
1990
Martin, M.W.Van Schmus, W.R., Martin, M.W., Sprowl, D.R., Geissman, J.Age, neodymium and lead isotopic composition and magnetic polarity for subsurface samples of the 1100 Ma midcontinent riftGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A174GlobalGeochronology, Geophysics -magnetics
DS1998-0574
1998
Martin, M.W.Hanson, R.E., Martin, M.W., Bowring, S.A., Munyanyiwauranium-lead (U-Pb) zircon age for Umkondo dolerites, eastern Zimbabwe: 1.1 Ga large igneous province ....Geology, Vol. 26, No. 12, Dec. pp. 1143-6.Zimbabwe, South Africa, AntarcticaGeochronology, Rodinia, Gondwana, Magmatism
DS1999-0087
1999
Martin, M.W.Bowring, S.A., Martin, M.W.high Pressure precision uranium-lead (U-Pb) geochronology, the tempo of evolution and the recordfrom Gondwana.Journal of African Earth Sciences, Vol. 28, No. 1, pp. 187-201.Geochronology
DS2001-1203
2001
Martin, M.W.Vinyu, M.L., Hanson, R.E., Martin, M.W., Bowringuranium-lead (U-Pb) zircon ages from craton margin Archean orogenic belt in northern Zimbabwe.Journal of African Earth Sciences, Vol. 32, No. 1, Jan. pp. 103-114.ZimbabweCraton, Geochronology
DS2003-0551
2003
Martin, M.W.Hargrove, U.S., Hanson, R.E., Martin, M.W., Blenkinsop, T.G., Bowring, S.A.Tectonic evolution of the Zambesi orogenic belt: geochronological, structural andPrecambrian Research, Vol. 123, 2-4, pp. 159-186.ZimbabweBlank
DS2003-1287
2003
Martin, M.W.Singletary, S.J., Hanson, R.E., Martin, M.W., Crowley, J.L., Bowring, S.A., KeyGeochronology of basement rocks in the Kalahari desert, Botswana, and implicationsPrecambrian Research, Vol. 121,1-2, Feb. 28, pp. 47-71.BotswanaGeochronology, Crustal provinces, belts - not specific to diamonds
DS200412-0790
2003
Martin, M.W.Hargrove, U.S., Hanson, R.E., Martin, M.W., Blenkinsop, T.G., Bowring, S.A., Walker, N., Munyanyiwa, H.Tectonic evolution of the Zambesi orogenic belt: geochronological, structural and petrological constraints from northern ZimbabwPrecambrian Research, Vol. 123, 2-4, pp. 159-186.Africa, ZimbabweTectonics
DS200412-1232
2004
Martin, M.W.Martin, M.W., Tannant, D.D.A technique for identifying structural domain boundaries at the Ekati diamond mine.Engineering Geology, Vol. 74, 3-4, pp. 247-264. Ingenta 1042990759Canada, Northwest TerritoriesMining - Ekati
DS200712-0690
2004
Martin, M.W.Martin, M.W., Tannant, D.D.A technique for identifying structural domain boundaries at the Ekati diamond mine.Engineering Geology, Vol. 74, 3-4, August pp. 247-264.Canada, Northwest TerritoriesDeposit - Ekati
DS1993-0975
1993
Martin, P.S.Martin, P.S.Diamond exploration opportunitiesPresentation notes Northeast Investment in Mining Conference, held New York, 8p.CanadaEconomics, Valuation
DS201112-0648
2011
Martin, R.Martin, R.Punctuated anorogenic magmatism.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, AbstractMantleMagmatism
DS1984-0534
1984
Martin, R.F.Morogan, V., Martin, R.F.Partial Melting of Fenitic Assemblages in the Oldoinyo Lengai Carbonatitic Volcano Tanzania.Geological Association of Canada (GAC), Vol. 9, P. 90. (abstract.).Tanzania, East AfricaBlank
DS1985-0080
1985
Martin, R.F.Bowden, P., Martin, R.F.Niger-nigeria Alkaline Ring Complexes: West Africa Representatives of African Phanerozoic Anorogenic Magmatism.Conference Report On A Meeting of Volcanics Studies Group He, 1P. ABSTRACT.Central Africa, NigerPetrogenesis, Geochemistry
DS1985-0467
1985
Martin, R.F.Morogan, V., Martin, R.F.Mineralogy and partial melting of fenitized crustal xenoliths in the Oldoinyo Lengai carbonatitic volcano, TanzaniaAmerican Mineralogist, Vol. 70, pp. 1114-1126TanzaniaCarbonatite
DS1995-1588
1995
Martin, R.F.Roelofsen, J.N., Martin, R.F., et al.Sequential alteration of mafic minerals in fenites from the Amba Bongar carbonatitic - alkaline complex GujaratGeological Association of Canada (