论文部分内容阅读
Chaohu is located in a deep part of carbonate ramp on the Lower Yangtze Block,which belonged to the low-latitude eastern Tethyan archipelago during the Early Triassic.Fossils were very rich in the Lower Triassic of Chaohu.Bivalves,ammonoids,conodonts were very common throughout the Lower Triassic,while fish fossils were generally rich in some beds of the upper part.It is one of the most typical sections for the Early Triassic chronostratigraphy in the world.Although various fossils had been studied in the 1980s and 1990s,recent studies based upon new and more detailed collections from the Lower Triassic of Chaohu showed that the conodont zonation needs revision.We collected Lower Triassic conodont fossils from continuous sections of the West Pingdingshan,North Pingdingshan and South Majiashan,Chaohu,Anhui Province,and updated zonations were made for each section.Eight conodont zones have been dis- tinguished.They are,in ascending order,Hindeodus typicalis zone,Neogondolella krystyni zone,Neospathodus kummeli zone,Neospath- odus dieneri zone,Neospathodus waageni zone,Neospathodus pingdingshanensis zone,Neospathodus homeri zone,and Neospathodus anhuinensis zone.The first occurrence of Neospathodus waageni eowaageni of the N.w.eowaageni subzone(i.e.the base of the N.waageni zone)is suggested as the marker to define the Induan–Olenekian boundary.
Chaohu is located in a deep part of carbonate ramp on the Lower Yangtze Block, which belonged to the low-latitude eastern Tethyan archipelago during the Early Triassic. Fossils were very rich in the Lower Triassic of Chaohu.Bivalves, ammonoids, conodonts were very common throughout the Lower Triassic, while fish fossils were generally rich in some beds of the upper part. It is one of the most typical sections for the Early Triassic chronostratigraphy in the world. Yet various fossils had been studied in the 1980s and 1990s, recent studies based upon new and more collections from the Lower Triassic of Chaohu showed that the conodont zonation needs revision.We collected Lower Triassic conodont fossils from continuous sections of the West Pingdingshan, North Pingdingshan and South Majiashan, Chaohu, Anhui Province, and updated zonations were made for each section.Eight conodont zones have been dis- tinguished.They are, in ascending order, Hindeodus typicalis zone, Neogondolella krystyni zo ne, Neospathodus kummeli zone, Neospathodorusne zone, Neospathodus waageni zone, Neospathodus pingdingshanensis zone, Neospathodus homeri zone, and Neospathodus anhuinensis zone.The first occurrence of Neospathodus waageni eowaageni of the Nweowaageni subzone (iethe base of the N. waageni zone) is suggested as the marker to define the Induan-Olenekian boundary.