湖北武汉下志留统坟头组化石组合及沉积环境

Fossil association and sedimentary environments of the Lower Silurian Fentou Formation in Wuhan,Hubei Province

文中报道了在武汉市铁箕山新发现的下志留统坟头组剖面。该剖面所在位置交通方便,出露较好,化石丰富,发现有三叶虫、腕足类、双壳类、腹足类、头足类、喙壳类、海百合、锥石、海星、鱼类及遗迹化石等,初步鉴定出13属17种。根据该剖面中的化石组合面貌及与邻区的对比认为,武汉地区坟头组的时代应为早志留世(兰多维列世)特列奇期。通过对该剖面化石组合特征、遗迹化石及其他相标志的分析,确定其下部为高能前滨环境,中上部为近滨和远滨环境。本剖面和相关化石材料及相标志的发现进一步丰富了武汉地区下志留统的生物面貌,并且为跨区域之间的地层和古环境对比提供了新资料。最后,作者建议取消武汉地区锅顶山组这一地层单位。

The paper reports a new section of the Lower Silurian Fentou Formation which has been measured in Tiejishan Hill.This well-exposed section situates in the southeast of Wuhan,Hubei Province,just five kilometers from the downtown of Wuhan.Abundant fossils have been collected from this site,they were identified as 13 genera with 17 species in total,including trilobites,brachiopods,bivalves,gastropods,rostroconcha and piscis.Some of the species such as Coronocephalus wuningensis,C.gaoluoensis,Kailia intersulcata,Latiproetus sp.,Striispirifer shiqianensis,Striispirifer disparatus,Howellella sp.,Nucleospira calypta are common in the Fentou Formation of Jiangsu and Anhui Provinces,the Shamao Formation of west of Hubei Province and the Xiushan Formation in southwest China;Technophorus peregriuns has been reported from the upper part of the Xiushan Formation in Guizhou Province before,and also from both of the Wangjiawan Formation and Ningqiang Formation of Shaanxi Province.Orthonota perlata occurs frequently in the Fentou Formation in the Lower Yangtze River region.Based on biostratigraphic correlation,fossil assemblage from the Fentou Formation in Wuhan area belongs to the Early Silurian（Telychian,Llandovery）.The lower part of the Fentou Formation might be deposited in a foreshore setting with a high energy,and the middle-upper part of this formation might be formed in an inshore and offshore setting with a lower energy.At last,the authors propose to cancel the stratigraphic unit of the Guodingshan Fomation in Wuhan area.