Phased Collapse of Biotic Communities and Its Relations to Marine Anoxia Near the Permian-Triassic Boundary in Shangsi, Sichuan

The process and causes of marine ecosystem collapse remains controversial during the Permian-Triassic mass extinction and could be different across varied paleogeographic settings. The collapse is likely linked to oxygen depletion. Continuous sedimentary sequences and abundant fossil records, along with a high-resolution chonostratigraphic framework from the upper Permian to the Lower Triassic offer an invaluable window to investigate the process of ecosystem collapse and its relationship with oxygen deficiency. The Shangsi section can be served as this window. Herein, we collected abundant specimens of brachiopods, bivalves, cephalopods, as supplements for previous data and integrated redox conditions (data of framboid pyrite). We analyze the process of ecosystem collapse and its causes particularly, discussed the influence of oxygen depletion on the collapse and mass extinction.