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Distribution of incompatible trace elements in rock-forming and accessory minerals from carbonatites as a tracer of magma evolution

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dc.contributor.supervisor Halden, Norman (Geological Sciences) en_US
dc.contributor.author Reguir, Ekaterina
dc.date.accessioned 2011-08-22T16:51:07Z
dc.date.available 2011-08-22T16:51:07Z
dc.date.issued 2011-08-22
dc.identifier.citation Reguir E.P., Camacho A., Yang P., Chakhmouradian A.R., Kamenetsky, D.S. & Halden N.M. (2010) Uranium-lead dating and trace-element study of perovskite from the Afrikanda plutonic complex, Kola Peninsula (Russia) using LA-ICP-MS. Mineralogy and Petrology, 100, 95-103. en_US
dc.identifier.citation Reguir E.P., Chakhmouradian A.R., Halden N.M., Malkovets V.G. & Yang P. (2009) Major- and trace-element compositional variation of phlogopite from kimberlites and carbonatites as a petrogenetic indicator. Lithos, 112S, 372-384. en_US
dc.identifier.citation Chakhmouradian A.R., Böhm C.O., Demény A., Reguir E.P., Hegner E., Creaser R.A., Halden N.M. & Yang P. (2009) “Kimberlite” from Wekusko Lake, Manitoba: Actually a diamond-indicator-bearing dolomite carbonatite. Lithos, 112S, 347-357. en_US
dc.identifier.citation Reguir, E.P., Chakhmouradian, A.R., Halden, N., Yang, P. and Zaitsev, A. (2008) Magmatic and reaction trends in magnetite from the Kerimasi carbonatites, Tanzania. Canadian Mineralogist, Special Issue, 46, 879-900. en_US
dc.identifier.uri http://hdl.handle.net/1993/4761
dc.description.abstract Carbonatites are igneous rocks comprising more than 50 modal percent of carbonate minerals and characterized by highly variable modal compositions. The majority of carbonatites are confined to intra-continental rifts, whereas occurrences associated with plate margins and orogenic settings are less common. Petrogenesis of carbonatites has been a matter of intense debate for several decades. The possible genetic models include crystallisation from a primary carbonatite magma, liquid immiscibility and crystal fractionation from carbonate-rich silicate magma. In contrast to the voluminous bulk-rock trace-element data and major-element analyses of minerals from carbonatites available in the literature, there has been no systematic study concerned with the trace-element signatures of the most common constituents of these rocks. This work is the first comprehensive study of the interrelations between the trace-element chemistry of the most common constituents of carbonatites, the geochemistry of these rocks, and their tectonic setting. The rock samples examined represent 21 different localities worldwide. The extent of major- and trace-element substitutions in amphibole, clinopyroxene, trioctahedral micas, dolomite, magnetite and perovskite is investigated in detail. The silicate minerals from carbonatites exhibit much larger compositional diversity than previously recognized. They can incorporate significant amounts of such petrogenetically important elements as Sr, REE, Zr, Nb and Ta. The majority of studied clino-amphibole- and clinopyroxene-group minerals exhibit previously unrecognized a bimodal distribution patterns of REE, which can be explained in terms of crystal chemistry of these phases. The trace-element signature of phlogopite from carbonatites, particularly Nb, Mn, Ni and Cr, is distinctly different from that of phlogopite from kimberlites, and can be used as a reliable petrogenetic indicator. Compositional variations in dolomite reflect magmatic and subsolidus processes in carbonatites. Magnetite from carbonatites follows a well-defined magmatic and previously unrecognized reaction trend. Contrary to prior studies, this mineral is only a minor host of HFSE in carbonatitic rocks. The U-Pb age data, trace-element and Sr-isotopic composition of perovskite from the Afrikanda carbonatite and clinopyroxenite suggest that the two rocks are not related by crystal fractionation. This study underlines the importance of a systematic approach in petrogenetic studies based on trace-element distribution. en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject carbonatites en_US
dc.subject trace-elements en_US
dc.subject partitioning en_US
dc.subject amphibole en_US
dc.subject clinopyroxene en_US
dc.subject phlogopite en_US
dc.subject magnetite en_US
dc.subject perovskite en_US
dc.subject petrogenesis en_US
dc.subject evolution en_US
dc.title Distribution of incompatible trace elements in rock-forming and accessory minerals from carbonatites as a tracer of magma evolution en_US
dc.type info:eu-repo/semantics/doctoralThesis
dc.degree.discipline Geological Sciences en_US
dc.contributor.examiningcommittee Sokolova, Elena (Geological Sciences) Bieringer, Mario (Chemistry) McDonald, Andrew (Laurentian University) en_US
dc.degree.level Doctor of Philosophy (Ph.D.) en_US
dc.description.note October 2011 en_US


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