ISOTOPE STRATIGRAPHY AND U-Pb DATING OF DETRITAL ZIRCONS FROM THE VENDIAN-CAMBRIAN DEPOSITS OF THE NORTH MUYA BLOCK
I.A. Vishnevskaya1,2,3, E.F. Letnikova1, N.A. Kanygina4, A.I. Proshenkin1, N.G. Soloshenko3, E.V. Vetrov1, V.Yu. Kiseleva1
1VS. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Koptyuga 3, Novosibirsk, 630090, Russia
2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia
3A.N. Zavaritsky Institute of Geology and Geochemistry, ul. Akademika Vonsovskogo 15, Yekaterinburg, 620016, Russia
4Geological Institute, Russian Academy of Sciences, Pyzhevskii per. 7, Moscow, 119017, Russia
Keywords: Пассивная континентальная окраина, изотопная хемостратиграфия, U-Pb датирование обломочных цирконов, источники сноса, реконструкции, Сибирская платформа, Passive continental margin, isotope chemostratigraphy, U-Pb dating of detrital zircons, provenances, reconstructions, Siberian Platform
Abstract
U-Pb dating of detrital zircons from the sandstones of the Mamakan Formation has been made. Geochemical and isotope parameters of the carbonate deposits of the Yanguda Formation in the Vendian-Cambrian cover of the North Muya continental block have been estimated. It has been established that only the Neoproterozoic (630-915 Ma) rocks of the North Muya block were the provenances of terrigenous material. In the least altered carbonate rocks of the Yanguda Formation, the 87Sr/86Sr ratio is within 0.70814-0.70879 and δ13C varies from -0.4 to + 1.9‰. Comparison of the evaluated isotope parameters with those of carbonate rocks of typical Vendian-Cambrian sections shows that the carbonate deposits of the Yanguda Formation accumulated in the Early Cambrian, about 520 Ma. Sedimentation of the Mamakan and Yanguda Formations took place in the local sedimentary basin in the Vendian-Early Cambrian, in the absence of tectonic activity within the North Muya block. Detrital material that formed during the destruction of the rocks of the Siberian Platform basement and cover was not supplied into the basin.
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