CARBON ISOTOPES IN THE UPPER RIPHEAN DEPOSITS OF THE BAIKAL GROUP IN WESTERN CISBAIKALIA: STRATIGRAPHIC IMPLICATIONS
E.M. Khabarov and V.A. Ponomarchuk
United Institute of Geology, Geophysics and Mineralogy, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Isotopes of carbonate and organic carbons, Neoproterozoic, stratigraphy, sedimentation settings, western Cisbaikalia
Pages: 1003-1023
Abstract
Study was given to the isotopic compositions of carbonate and organic carbons in the deposits of the Baikal Group in western Cisbaikalia. The section of this rock group is considered as a stratotype for the Baikalian, the upper subunit (younger than 850 Ma) of the Upper Riphean series. Results of petrographic, geochemical, and isotope studies show that relatively pure limestones and dolomites, in contrast to mixed carbonate-siliciclastic rocks, might have preserved a near-primary carbon isotope composition despite their strong recrystallization. The studied deposits have high δ13C
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