Facies and Sequence Stratigraphy of the Zhuya Group in the Ura Uplift (Vendian, Southern Middle Siberia)

The facies were studied and the sequence-stratigraphic model of the Zhuya Group in the Ura Uplift (Vendian reference section, southern area of Middle Siberia) was constructed. The whole Zhuya Group represents a single sequence bounded by unconformities. Sediments of the Kullekin member were accumulated in the high-energy coastal-marine environments during sea-level lowstand. The development of transgression initiated a carbonate ramp on the Siberian Craton. The rest of the Zhuya Group above the Kullekin member records the gradual progradation of the ramp and basin compensation of accommodation space during sea-level highstand. The trajectory of the negative C isotope excursion of the Zhuya Group, correlated with the Shuram–Wonoka excursion, follows the relative sea level changes, reaching its nadir close to the maximum of transgression. Elucidation of the reason for the coincidence of these trends requires additional regional and interregional studies. The occurrence of Neoproterozoic zircons in the Kullekin sandstones derived from a northern source reflects accretion of the Baikal–Muya terrane to the Siberian Platform and can be attributed to either pre-Zhuya inversion of the Patom basin (collision) or erosion of synsedimentary tuffs on the Siberian Platform (soft accretion).