REFERENCE SECTION AND UPPER PERMIAN ZONATION IN SOUTHEASTERN MONGOLIA

Abstract

A reference section of the Upper Permian deposits of the Tethyan basin in southeastern Mongolia is defined. The brachiopod zonation of the deposits is described. Two zones corresponding to one transgressive phase are united into a horizon. The distribution of brachiopod zones within the areas of Upper Permian exposures in different structural-facial zones is outlined. Brachiopod assemblages of the zones are correlated with those from coeval units in the Boreal basin of northeastern Mongolia, Arctic regions, and central and northeastern Asia. Late Permian migration paths of brachiopods of the Ussuri Province are considered. Available paleontological records point to the existence of the Late Paleozoic South Mongolian microcontinent, whose shelf was inhabited by peculiar fauna of the mixed Boreal-Tethyan type.