江西修水流域上奥陶统五峰组的笔石分带

GRAPTOLITE ZONATION IN WUFENG FORMATION OF XIUSHUI GORGE, JIANGXI PROVINCE

重新研究了江西武宁官塘源五峰期地层剖面，将原五峰组和原新开岭组合二为一称为五峰组，并对五峰组的笔石带进行了修订：取消Ｐａｒａｏｒｔｈｏｇｒａｐｔｕｓｕｎｉｆｏｒｍｉｓ带，改称Ｄｉｃｅｌｏｇｒａｐｔｕｓｓｚｅｃｈｕａｎｅｎｓｉｓ带为Ｄｉｃｅｌｏｇｒａｐｔｕｓｃｏｍｐｌｅｘｕｓ带。修订后的笔石序列自下而上是：Ｄｉｃｅｌｏｇｒａｐｔｕｓｃｏｍｐｌｅｘｕｓ带、Ｔａｎｇｙａｇｒａｐｔｕｓｔｙｐｉｃｕｓ带和Ｄｉｃｅｒ－ａｔｏｇｒａｐｔｕｓｍｉｒｕｓ带。

With the well developed Wufengian strata and transitional position between the Yangzi and Jiangnan Stratigraphic regions, the Xiushui gorge of the Jiangxi province has been regarded as one of the most important districts for the research of Wufengian graptolitic biostratigraphy in south China. In this paper, the Wufeng strata in the vicinity of the Guantangyuan village, Wuning conuty are restudied with some revisions of the defination and biozonation of the Wufeng Formation. The Xinling Formation and the Wufeng Formation previously used in this district are now incorperated into one Formation, ie. the Wufeng Formation, in which the Paraorthograptus uniformis zone is canceled and the Dicellograptus szechuanensis zone is replaced by the Dicellograptus complexus zone. Consequently, the graptolitic sequence after these revisions in the Wufeng Formation of Xiushui gorge could be arranged as follows with an ascending order: the Dicellograptus complexus zone, the Tangyagraptus typicus zone and the Diceratograptus mirus zone.