二叠系-三叠系界线的事件地层学标志

<正> 传统的二叠-三叠系界线,是以喜马拉雅山的Otoceras层的底作为三叠系底界(Die-ner 1912)。70年代以来,国际上提出了多种方案(Waterhouse 1973,1976;Kozur 1977;Newell 1978),我国80年代出现了分歧意见(李子舜、姚建新1984;李子舜、詹立培等1986)。1986年在意大利举行的“西特提斯南阿尔卑斯的二叠系及二叠-三叠系界线国际

On event stratigraphic markers of the Permian-Triassic boundary

There are two different views on the definition of the Permian-Triassic boundary among Chinese scientists: 1.Conodont Hindcodus pareus is regarded as a lime marker of the basal Triassic, and the lower part of the Otoceras Zone is put in the top of the Permian; 2.The Otoceras Zone is accepted as the basal Triassic according io the traditional definition and it coincides with the lower range of H.parvtes.In order to discuss the definition of the Permian-Triassic boundary, two concepts, biostratigraphic event and biologic event, must be distinguished.A boundary clay bed is an event stratigraphic marker based on biologic events.H.parvus makes its first occurrence at different stratigraphic levels in various sections of South China.The Otoceras Zone, never found to overlap the typical Permian fossiliferous bed in South China, represents the Griesbachian Stage, the basal Triassic, according to the traditional view.Bui the first occurrence of Otoceras in a section does not represent the position of the Permian-Triassic boundary.The line between the new comers of Triassic organisms and the mass extinction at the end of the Permian is the Perman-Triassic boundary.This is a consensus of Chinese scientists.