MARINOAN GLACIATION ON THE SIBERIAN PLATFORM: LA ICP-MS DATING OF ZIRCONS FROM THE TUFF IN THE BOLSHOY PATOM FORMATION ON THE URA UPLIFT
S.V. Rudko1, S.V. Malyshev2, M. Ovtcharova3, A.V. Drazdova1, I.V. Fedyukin4, V. B. Khubanov4, A.S. Dubensky1, V.S. Sheshukov1.
1 Geological Institute of the Russian Academy of Sciences, Moscow, Russia
2Institute of Earth Sciences, Saint Petersburg, Russia
3University of Geneva, Geneva, Switzerland
4Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences, Moscow, Russia
Keywords: Vendian, Cryogenian, Ediacaran, Siberian Platform, Middle Siberian glacial horizon, Marinoan glaciation
Abstract
Using LA ICP MS dating of zircons, the age of the tuff (633±7 million years) of the Bolshoi Patom Formation at the base of the Vendian reference section in the south of the Siberian Platform (Ura Uplift) was estimated. The Vendian of the Siberian Platform was found to include the last Cryogenian (Marinoan) glaciation, and the postglacial sequence of the Vendian corresponds to the Ediacaran. In light of the obtained dating, the chronostratigraphy of the Riphean-Vendian deposits on the Ura Uplift and in adjacent areas is considered. The available geochronological and sequence stratigraphic data indicate the presence of hidden stratigraphic unconformity above the glacial horizon at the base of the Vendian, caused by glacio-isostasy.
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