New biostratigraphic framework for the Triassic–Paleogene in the Neo-Tethys realm of southern Xizang (Tibet), China

Abstract

Abstract Multifaceted biostratigraphic work on Triassic to Paleogene strata in southern Xizang (Tibet), western China, in the last decades allows a new, refined biochronostratigraphic framework in the Qinghai–Xizang plateau region. Synthesis of the latest biostratigraphic progress is carried out in this paper to build a new integrated biostratigraphic scheme comparable to the international Geological Time Scale. The scheme incorporates key fossils as many of each system, such as ammonites, calcareous nannofossils, conodonts and foraminifers. Other fossil groups that are helpful for stratigraphic division and interregional correlation are also contained. These include bivalves, miospores and radiolarians, some of which, e.g. radiolarians and miospores, not previously well explored, are now utilised for new zones. Biostratigraphic zones of this new integrative system, especially the Lower Triassic conodonts and ammonites, uppermost Triassic–Lower Jurassic ammonites, Upper Cretaceous planktonic foraminifers and calcareous nannofossils, correlate well with the international standards. The results are tabulated as four new comprehensive biostratigraphic charts, which, we hope, will provide a new and more reliable chronostratigraphic foundation for study of Neo-Tethys.