Search academic texts

Information × Registration Number 0211U001020, 0109U007348 , R & D reports Title Comparative petrology of Neoproterozoic basalts of the western, northern and eastern regions of the East-European platform: compositions of magmas and their mantle sources popup.stage_title Head Shumlyanskyy Leonid Vladyslavovych, Доктор геологічних наук Registration Date 12-01-2011 Organization M.P. Semenenko Institute of Geochemistry, mineralogy and Ore Formation popup.description2 Neoproterozoic magmatic activity was widespread within the East-European platform. Volynian flood basalt province formed at 555 Ma. Earliest rocks contain largest portion of the lower crustal (and lithospheric material) while upwards portion of the material originated from the enriched mantle gradually increases. At the Western Urals province bi-modal complexes were emplaced at 730-670 Ma; these were followed by toleiitic basalts at 670 Ma. These were followed by subalkaline and alkaline-ultramafic complexes at 625 Ma. Initial melts were formed at relatively low degree of mantle melting at the presence of garnet. Geochemical composition of the bi-modal complexes evidences about their formation from the depleted mantle and about large input of crustal material especially at the stage of acid magmatism. At the Onega-Timan magmatic province continental tholeiitic basalts were formed at c. 670 Ma. At the Late Vendian magmatism gained mafic alkaline properties. At this stage lamprophiric rocks were formed. High positive ?Nd values indicate mantle source of the initial melts. The mantle source was re-melted while most incompatible elements were extracted during previous acts of melting. Mentioned geochemical and isotopic peculiarities allow suggestion about generation of the initial melts at the small degrees of melting of the asthenosperic source presumably of lherzolitic composition. Product Description popup.authors Шумлянський Леонід Владиславович popup.nrat_date 2020-04-02 Close