Palaeontology characteristics and sedimentary environment of the Upper Triassic Xujiahe Formation in the Pujiang area,Sichuan,China

Survey and systematic sampling were conducted for Xujiahe Formation located at the anticline of Xiongpo in Pujiang County.According to paleontology fossil assemblage,two biological zones can be divided:namely Weiyuanella rhomboidallis-Per-mophorus emeiensis assemblage and Zamites jiangxieensis-Clathropteris assemblage.In combination of lithological and stratigraphic comparison,it is asserted that Xujiahe Formation of this area belongs to the fifth and sixth rock members.The sedimentary facies of Xujiahe Formation in this area is delta facies,which can be subdivided into two subfacies namely delta plain and delta front.The conclusion has been verified the contact relationship between Xujiahe Formation and its overlying Middle Jurassic Xintiangou Forma-tion is parallel unconformity,also Lower Jurassic series are missing.