中国二叠系的底界

THE BASE OF THE PERMIAN SYSTEM IN CHINA

牙形刺是二叠系生物地层的主导门类 ,二叠系的三统九阶的界线层型 (GSSP)都将用牙形刺定义。我国石炭 -二叠系 (C/P)的分界应采用与国际上一致的标准 ,即用牙形刺 Streptog-nathodusisolatus的首次出现定义二叠系的底界。S.isolatus在我国华南、华北均有分布 ,可精确地确定二叠系的底界。华北太原组应归下二叠统 Asselian阶 ,我国 C/P界线地层和 Streptog-nathodus的分类 ,有待做更精细的研究。

Conodonts are the leading fossil group for the Permian biostratigraphy. The definition of all stages of the Permian System should be defined by conodonts. The base of the Permian System in China should be defined by the FAD of Streptognathodus isolatus , keeping consistency with the international standard. S. isolatus is widely distributed both in South China and in North China Platforms. It can be used precisely to define the base of the Permian System. The Taiyuan Formation should be assigned to Lower Permian rather than Upper Carboniferous. The taxonomy of the genus Streptognathodus should be studied thoroughly.