扬子北缘钟祥地区奥陶系弗洛阶笔石动物群研究

湖北钟祥下奥陶统弗洛阶岩性以灰黑色页岩为主,夹粉砂岩及灰岩透镜体, 化石丰度和分异度高。通过系统的化石采集和鉴定, 于钟祥温峡口剖面识别出笔石7属31种, 大体上为扬子地台区的常见属种。自下而上分为Didymograptellus bifidus带、Corymbograptus deflexus带和Azygograptus suecicus带。该序列与宜昌?南漳地区一致, 但在笔石动物群组成面貌上差异较大,可能与钟祥地区在早奥陶世位于扬子台地边缘, 富集的营养物质和低氧的环境更利于笔石动物群的繁盛和笔石化石的保存有关。

STUDY ON ORDOVICIAN FLOIAN GRAPTOLITE FAUNA IN ZHONGXIANG AREA, NORTHERN MARGIN OF THE YANGTZE PLATFORM

The Florian in Zhongxiang, Hubei Province is mainly composed of grayish black shale with siltstone and limestone lens, and has high abundance and diversity of fossils. Thirty-one species belonging to 7 genera of graptolites were identified in Wen-xiakou section through systematic collection and identification, which are common genera and species in Yangtze platform area. There are Didymograptellus bifidus Biozone, Corymbograptus deflexus Biozone and Azygograptus suecicus Biozone in ascending order, which is consistent with Yichang and Nanzhang area, but the composition of fossil genera and species is quite different. Zhongxiang area is located at the margin of Yangtze Platform in Floian with rich nutrients and low oxygen environment, which are beneficial to the flourishing of graptolite fauna and the preservation of graptolite fossils.