Biostratigraphy and correlation of several Permian-Triassic boundary sections in southwestern China

Abstract

Detailed investigations of five complete Permian-Triassic boundary sections in southwestern China demonstrate the transitional nature of the Permian-Triassic boundary and the presence of a white clay at the boundary in the working area. The uppermost Permian is represented by the Neochonetes substrophomenoides-Notothyris crassa-Waagenites pigmaea brachiopod assemblage or the Clarkina changxingensis-C. deflecta conodont zone. The transitional beds of basal Triassic are represented by the Lingula fuyuanensis-Crurithyris flabelliformis brachiopod assemblage, or the Pteria ussurica variabilis-Towapteria scythicum-Eumorphotis multiformis bivalve assemblage, which is overlain everywhere by the Pseudoclaraia wangi bivalve zone. Faunal correlations show that the stratigraphy and faunal composition of the Permian-Triassic boundary sections in southwestern China do not differ substantially from the other two Global Stratotype Section Point candidates in south China and the transitional beds approximately correspond to the Otoceras woodwardi ammonoid zone, but the Hindeodus parvus conodont zone only corresponds to the upper part of transitional beds.