中文摘要：

峡东地区埃迪卡拉系陡山沱组自下而上可分4个岩性段：第1段为1．5～5m具帐篷和板裂构造的“盖帽白云岩”；第2段是90-120m白云质灰岩夹黑色页岩，富含燧石结核；第3段为40-70m的白云岩夹燧石层和燧石结核；第4段10～20m为黑色碳质页岩夹碳酸盐岩透镜体。根据对该区九龙湾、王丰岗、田家园子、九曲脑、晓峰河、樟村坪等多条陡山沱组剖面的重新调查，确认第2和第3段分别含有不同的疑源类组合，二者被之间出现的δ^13C负漂移（EN2）所分隔。下组合以Tianzhushania和高分异的具刺疑源类出现为特征。上组合与下组合的区别是：（1）Tianzhushania绝迹；（2）出现大量表面光滑，介于90--1509m的球状膜壳；（3）高分异的具刺疑源类既包括下伏上延的种类，又含有首次出现的新类型；（4）还出现可能为单细胞原生动物的微化石；（5）管状化石震旦圆圆茎（Sinocyclocylicus guizhouensis）首现。

英文摘要：

The Ediacaran Doushantuo Formation in the Yangtze Gorges is subdivided into four lithostratigraphic members in ascending order. Member 1 is about 1. 5-5m thick cap dolomite with tepee-like structures, sheet cracks. Member 2 consists of 90- 120m thick organic-rich dolomitic limestones and interbedded black shales, with abundant black chert nodules. Member 3 is 40-70m thick and consists of grey dolostones with thin bedded chert and irregular chert nodules. Member 4 is about 10-20m thick and consists of black shale with large carbonate concretions. Based on investigations in Jiulongwan, Wang-fenggang, Tianjiayuanzi, Jiuqunao, Xiaofenghe and Zhangcunping sections, we confirm the presence of two different assemblages separately appear in the second and third members, which were separated by a 313C negative excursion （EN2）. The lower assemblage is characterized by Tianzhushania and a diverse suite of large acanthomorphic acritarchs. The upper assemblage is distinguished from the lower assemblage by （1） extinction of Tianzhushanial （2） occurrence of abundant 100- 150μm, smooth walled spherical microfossils; （3） highly diverse canthomorphic acritarchs, including species extended from the lower member and new forms in this member; （4） occurrence of unnamed new forms of metazoan; （5） occurrence of Sinocyclocylicus guizhouensis.