BIOSTRATIGRAPHY OF THE MARINE PALEOGENE IN THE WEST SIBERIAN PLATE

Abstract

The regional stratigraphic scheme suggested for the marine Paleogene deposits in the West Siberian plate is based on investigation results of macro- and microfossils (foraminifers, dinoflagellales, radiolarians, diatomaceous algae, silicoflagellates, Elasmobranchii, ostracodes, pollen, and spores). In the West Siberian plate, like in many structural-facies zones of the East European platform, there was a hiatus in sedimentation at the Cretaceous-Paleogene boundary. The Talitsa Horizon corresponds here to the Danian and Selandian presumably coupled with the initial Thanetian. The lower Lyulin-Vor Subhorizon is dated back to the late Paleocene; the middle Lyulin-Vor Subhorizon is correlated with the Ypresian, and the upper one is attributed to the interval spanning the second half of the Ypresian and Lutetian. The Tavda Horizon of the Bartonian-Priabonian age presumably comprises as well the terminal Lutetian. The Kurgan Beds (s. str.) representing marine facies of the Atlym Horizon correspond in the type area (near the town of Kurgan) to the lower Oligocene. Boundaries of these lithostratigraphic units are diachronous, since the Paleoarctis in the north and the Tethys in the south were connected with the epicontinental West Siberian sea basin producing an irregular impact on sedimentation in the latter.