Pb-Pb dating of the Dal’nyaya Taiga Group in the Ura uplift of southern Siberia: Implications for correlation of C-isotopic and biotic events in the Ediacaran

Abstract

The Ura uplift section in southern Middle Siberia is one of the key sections for testing of climatic changes and evolutionary events of the Ediacaran, as well as the development of the stratigraphic framework for this period. The low latitude glacial deposits, positive δ13C anomalies and the Ediacaran Complex Acanthomorph-dominated Palynoflora are observed in the Dal‘naya Taiga Group succession, which occurs in the lower part of this section. The “Shuram-Wonoka” negative δ13C anomaly is recorded in the overlying Zhuya Group. We selected three horizons of highly Sr-enriched limestones in the Dal'nyaya Taiga Group for Pb-Pb isochron dating. The obtained ages (613 ± 56 Ma 581 ± 16 Ma and 575 ± 20 Ma) are the first geochronological confirmation of the Ediacaran age of the Dal‘nyaya Taiga postglacial deposits and provide a restriction for the timing of δ13C anomalies and diversification of acanthomorph acritarchs in Siberia.