江西二叠－三叠系界线

本文描述了江西省北部、中部、南部地区二叠－三叠系界线剖面各１条，对每条剖面进行沉积相分析，从生物地层学角度论证其界线存在的可靠性。Ｈｉｎｄｅｏｄｕｓｐａｒｖｕｓ在江西修水清水岩乡东岭的发现是中国的又一新发现地区。二叠－三叠纪生物地层界线以Ｈ．ｐａｒｖｕｓＭｏｒｐｈｏｔｙｐｅ１的首次出现为难；“界线粘土”层的底界属二叠－三叠系事件地层界线，与生物地层界线不是一回事，生物地层界线比事件地层界线在江西约高出１６─２０ｃｍ；建议在二叠－三叠系界线研究中，最好不用“混生层”或“过渡层”，而改为界线地层或界线层。

PERMIAN-TRIASSIC BOUNDARIES IN JIANGXI,CHINA

The three sections across the Permian-Triassic boundary in the northern,central,and southern parts of Jiangxi Province are described in detail. An analysis on lithology has been made for each section.Eventostratigraphic boundary and biostratigraphic boundary have been clearly distinguished in the study of the Permian-Triassic boundaries in Jiangxi for the first time.The basal limit of the "Boundary Clay" bed,which is a good marker for the eventostratigraphic boundary,is not identical with the biostratigraphic boundary.This paper suggests that in the study of the Permian-Triassic boundary it is better to use"boundary beds" instead of "mixed beds" or "transitional beds".A revised definition for the Permian-Triassic biostratigraphic boundary has been proposed by Wang Cheng-yuan,which is placed at the first appearance of Hindeodus parvus Morphotype 1.This boundary falls within boundary bed 2 at the Zhongxin Dadui section in Changxing,15cm higher than the eventostratigraphic boundary,representing also the upper limit of the Changhsingian Stage.It is 16cm higher than the eventostratigraphic boundary at the Yangou section in Luoping,and 20cm higher at the Dongling section in Xiushui,Jiangxi.