BIOSTRATIGRAPHY AND CORRELATION OF SEVERAL PERMIAN-TRIASSIC BOUNDARY SECTIONS IN SOUTHWESTERN CHINA

Detailed investigations of five complete Permian-Triassic boundary sec tions in southwestern China demonstrate the transitional nature of the Permian-Triassic boundary and the presence of a white clay at the bou ndary in the working area. The uppermost Permian is represented by the Neochonetes substrophomenoides-Notothyris crassa-Waagenites pigmaea b rachiopod assemblage or the Clarkina changxingensis-C. deflecta conodo nt zone. The transitional beds of basal Triassic are represented by th e Lingula fuyuanensis-Crurithyris flabelliformis brachiopod assemblage , or the Pteria ussurica variabilis-Towapteria scythicum-Eumorphotis m ultiformis bivalve assemblage, which is overlain everywhere by the Pse udoclaraia wangi bivalve zone. Faunal correlations show that the strat igraphy and faunal composition of the Permian-Triassic boundary sectio ns in southwestern China do not differ substantially from the other tw o Global Stratotype Section Point candidates in south China and the tr ansitional beds approximately correspond to the Otoceras woodwardi amm onoid zone, but the Hindeodus parvus conodont zone only corresponds to the upper part of transitional beds.