Mississippian–Pennsylvanian Boundary Beds in the South Urals

Abstract

This work presents a study of the Mississippian–Pennsylvanian (Serpukhovian–Bashkirian) boundary beds in the eastern regions of the Russian Platform and in the South Urals. The boundary beds have been studied in boreholes in the eastern Russian Platform and in the Pre-Uralian Foredeep, and in natural outcrops in the South Urals. In the Russian Platform, the upper Serpukhovian includes the Protvian and Zapaltyubian substages. The lower portion of the Bashkirian includes the Voznesenskian and Krasnopolyanian substages. In the South Urals, there are two subregional stratigraphic schemes for the lower Carboniferous, for the West Uralian and East Uralian subregions. The West Uralian Subregion includes the Cisuralian, West Uralian, and Central Uralian facies zones, and the upper Serpukhovian is subdivided there into the Protvian and Staroutkinskian (= Yuldybaevian in the Central Uralian facial Zone) regional substages, and in the East Uralian Subregion (Magnitogorsk Zone) into the Khudolazian and Chernyshevkian substages. This paper briefly summarizes features of the boundary beds in each of these regions, including ammonoids, conodonts and foraminifers.