CHEMOSTRATIGRAPHY OF THE VENDIAN–CAMBRIAN CARBONATE SEDIMENTARY COVER OF THE TUVA–MONGOLIAN MICROCONTINENT
I.A. Vishnevskaya, E.F. Letnikova
Keywords: Isotope chemostratigraphy, Vendian, Neoproterozoic, carbonate rocks, δ13C, 87Sr/86Sr
Abstract
The carbonate sediments from the Vendian–Cambrian shelf of the Tuva–Mongolian microcontinent were dated by Sr and C isotope chemostratigraphy. Analysis of the Sr-isotopic characteristics (0.70725–0.70873) and δ 13C variations (+10.5 to –3.5‰), as well as their comparison with the data on the key sections of Siberia, Africa, Central Asia, Australia, South America, and Spitsbergen, showed that the carbonate sedimentary cover of the Tuva–Mongolian microcontinent accumulated at 600–520 Ma and the carbonate sediments of the Muren Formation and the basal horizons of the Bokson Group near the Ukha-Gol River are the oldest. Their sedimentation followed the Marinoan global glaciation.
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