Conodont biostratigraphic division of Lower Permian-Lower Triassic carbonate rocks in Cuoqin Basin, Tibet

Carbonate sediment is widely developed above Lower Permain Angjie Formation in Coqin basin, which was disintegrated by previous research to establish several formations. Five conodont zones of Lower Permian-Lower Triassic were identified in the carbonate rocks through conodont studies, namely Mesogondolella siciliensis -Sweetognathodus subsymmetricu zone, Mesogondolella idahoensis zone, Jingondolella aserrata zone, Clarkina meishanensis zone, Neospathodus dieneri zone, and the stratigraphic age of the Xiala Formation was constrained at Lower Permian Kungurian-the later of Middle Permian.