在讨论当前全球末前寒武系和中国震旦系年代地层划分中存在问题的基础上 ,根据三峡地区震旦纪和寒武纪生物地层学、层序地层学和年代地层学的综合研究 ,作者认为 :( 1 )中国传统的震旦系底界和后来建立的陡山沱阶和灯影峡阶的底界是不合适的 ,前者位于不整合面上 ,而后二者的底界分别位于相对动荡的低位域的开始和由海退所形成的高位域的开始 ,不仅横向变化大 ,而且很难保存和发现可供对比的生物和化学标志。 ( 2 )建议将中国震旦系的底界上移到陡山沱组第 2段近底部 ,即靠近陡山沱组第 2段黑色页岩与第 1段灰白色白云岩之间的界线 ,以出现分异度高、个体较大、构造复杂的疑源类为标志 ,该界面与南沱冰期后所形成的海侵生物面基本一致 ;同时主张将原灯影峡阶的底界要么下移到陡山沱组第 4段产庙河生物群的黑色页岩底部 ,要么上移到灯影组产文德生物群的石板滩段黑色页岩夹炭质灰岩底部 ,因为这两个界面分别与南沱冰期后形成的层序 2和层序 3的最大海泛面基本一致。 ( 3)根据同位素年代学研究 ,指出陡山沱组第 4段 ,即庙河生物群的 Rb-Sr等时线年龄为 ( 6 85± 9) Ma,而水井沱组底部含三叶虫的黑色页岩的 Rb-Sr等时线年龄为 ( 5 30± 8) Ma Based on the discussion of the existing problems in the stratigraphic division of the current Precambrian and Sinian years in China, according to the comprehensive studies of Sinian and Cambrian bio-stratigraphy, sequence stratigraphy and geochronology in the Three Gorges area, It is considered that: (1) The bottom of the traditional Sinian system in China and the later founding of the Doushantuo Tujia and Lampshade Gap are not suitable. The former is located on the unconformity, and the bottom boundary of the latter is located in relative turbulence The beginning of the low-level domain and the beginning of the high-level domain formed by the regression not only make large horizontal changes, but also make it difficult to preserve and find biological and chemical markers for comparison. (2) It is proposed to move the bottom of the Sinian in China to the bottom near the second section of the Doushantuo Formation, that is, the boundary between the black shale in the 2nd segment of the Doushantuo Formation and the pale-white dolomite in the 1st segment, The appearance of high degree of differentiation, individual larger, complex structure of the suspected source class as a symbol of the interface with the formation of the Nantuo ice age after the transgression biological surface basically the same time advocate the original light shadow gorge or bottom of the border down to The bottom of the black shale of the Miaomiao River biota in the fourth section of the Doushantuo Formation either moves up to the bottom of the black shale clathra carbonaceous limestone in the Shibantan section of the Wendeng biota, Wendeng Biota, because these two interfaces are respectively The maximum sea surface of the sequence 2 and the sequence 3 formed after the Nantuo glaciation are basically the same. (3) According to the isotopic chronological study, it is pointed out that the Rb-Sr isochron age of the fourth member of the Doushantuo Formation, that is, the Miaohe biota, is (6 85 ± 9) Ma, while the Trilobite The Rb-Sr isochron age of black shale is (5 30 ± 8) Ma