End-Permian Faunas from Yangtze Basin and Its Marginal Region: Implications for Palaeogeographical and Tectonic Environments

The Permian-Triassic mass extinction was contro11ed by the palaeoenvironment evolution. However, the palaeogeo- graphic feature, tectonic setting and biota physio1ogica1 feature also influenced the biotic evolution and their spatia1 ranges. To reconstruct the palaeogeographica1 features of the basin, we conduct research on thelatest Permian sedimentary feature, radio- 1arian palaeobathymetry and biota of northern and southern parts of Yangtze Basin, It is proposed that the water depth in- creased towards northern margin of the basin in the north part of the Yangtze Basin, facing the northern margin of the Yangtze Basin and opening to the eastern Qinling-Dabie deep sea; whereas the water depth increased towards southern margin of the ba- sin in the south part of the Yangtze Basin, facing the southern margin of the Yangtze Basin and opening to the Paleotethys Ocean. The evolution of organisms and environments of the Yangtze Basin during the Permian waslinked to the counterpart in the Paleotethys and is therefore, not a1oca1 episode separated from other parts of the world, and rather representative in a re- giona1 scale or even in the world. In addition, the water depth in the north part of the Yangtze Basin was sha11ower than that in the south part. It is also suggested that the co11ision between the north part of South China B1ock and the North China B1ock happened after the End-Permian. The fina1 co11ision between the Yangtze B1ock and the Cathay Accreting B1ock happened at the end of the Permian or even Triassic a1ong the southwestern part, based on that it was deposited in a setting of ocean during the Late Palaeozoic in the area oi Qinzhou-Fangcheng and such a setting continued to the End-Permian or even to the Triassic.