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三峡地区震旦系的三层式地层结构 (冰积层 ,陡山沱组特色的大型带刺疑源类组合层 ,埃迪卡拉生物化石层 )在世界其它地区是常见的。通过生物和化学地层对比我们认为陡山沱组及其化石组合层是在马雷诺恩 ( Marinoan)冰期之后、埃迪卡拉生物群分异之前沉积的。根据这一地层对比方案以及西伯利亚、纳米比亚和阿瓦龙半岛 ( Avalon Peninsula)新元古代地层的精确放射性同位素测年资料 ,陡山沱组的沉积年龄很可能在五亿五千万年至六亿年之间。这一估计要新于以前发表的铷锶法或钾氩法测定的陡山沱组黑色页岩或海绿石年龄。更精确地估算陡山沱组的沉积年龄还有待于在陡山沱组地层中发现火山灰以及对火山灰的精确年龄测定 ,但我们根据地层对比估算的陡山沱组年龄 ,为评估庙河和瓮安陡山沱组生物群的演化意义提供了必要的地层框架。
Three layers of stratigraphic structure of the Sinian in the Three Gorges area (icy strata, large primed source assemblages of the Doushantuo Formation, and Edicala fossil beds) are common in the rest of the world. By comparison of biological and chemical stratigraphy we believe that the Doushantuo Formation and its fossil assemblage were deposited prior to the Edicala biome differentiation after the Marinoan glacial period. Based on this stratigraphic comparison program and accurate radioisotope dating of Neoproterozoic strata in Siberia, Namibia and the Avalon Peninsula, the sediment age of the Doushantuo Formation is likely to be between 550 and 600 million Years. This estimate is to be new to the black shale or glauconite age of the Doushantuo Formation as determined by the previously published rubidium-strontium or potassium-argon method. A more precise estimation of the sedimentary age of the Doushantuo Formation has yet to be found in the Doushantuo Formation strata and accurate dating of volcanic ash. However, based on the stratigraphic comparisons of the age of the Doushantuo Formation, The evolutionary significance of the Doushantuo biota provides the necessary stratigraphic framework.