Biostratigraphic division of the Upper Carboniferous to Middle Permian in Zhejiang

This paper introduced sixteen fossil zones (eleven new established fossil zones) of the Upper Carboniferous to Middle Permian in Zhejiang province.The study results showed the fossil zones were distributed in the Laohudong formation, the Huanglong formation,the Chuanshan formation, the Liangshan formation,the Qixia formation, the Gufeng formation and the lower part of Longtan formation,which can be compared with nine stages of the Huashiban Stage,the Dala Stage,the Xiaoyao Stage,the Zisong Stage,the Longlin Stage,the Qixia Stage, the Xiangbo Stage,the Maokuo Stage and the Lengwu Stage.The boundaries of the Upper Carboniferous, the Lower Permian and the Middle Permian were discussed.The authors proposed that the basal boundary of Upper Carboniferous was inexistence and the sediment was lacking in Luosu Age.The basal boundary of Lower Permian was lying at the bottom of the Sphaeroschwagerina subrotunda fusulinid zone based on the standard of the first appearance of the Sphaeroschwagerina genus. Carboniferous-Permian boundary was located between Triticites subcrassulus fusulinid zone and Sphaeroschwagerina subrotunda fusulinid zone.The basal boundary of Middle Permian was lying at the bottom of the Orthotichia chekiangensis brachiopod assemblage zone based on the boundary standard of the first appearance of the Orthotichia chekiangensis.Further research indicated that the Chuanshan formation is a boundary, lithostratigraphic unit which spanned the Carboniferous-Permian.The lower part of it belonged to the Upper Carboniferous Xiaoyao Stage,the middle part belonged to the Lower Permian Zisong Stage and the upper part belonged to the Lower Permian Longlin Stage .