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本文测定了湖北宜昌三峡剖面震旦系海相碳酸盐岩样品的碳同位素组成。研究表明：震旦纪扬子区海水的δ１３Ｃ值显示出大幅度变化，南沦冰期δ１３Ｃ为低值（－４％）；陡山沦早期δ１３Ｃ值迅速上升，达到５～６％，陡山沦期δ１３Ｃ值一股在０～５‰之间；灯影期δ１３Ｃ值较平稳，一般在２．０～３．４‰。之间。导致震旦纪海水δ１３Ｃ值大幅度变化的原因主要是由于以疑源类和近岸藻类等光合作用的海洋植物群体为主体的大量生物的繁盛、全球海洋沉积速率的迅速上升，以及海洋深部水柱中缺氧层的存在。
This paper measured the carbon isotopic composition of the Sinian marine carbonate samples from the Three Gorges section in Yichang, Hubei Province. The results show that the δ13C value of seawater in the Sinian Yangtze area shows a significant change, while δ13C in the South Ice Age is low (-4%). The δ13C value of the seawater rapidly increases to 5 ~ 6% The δ13C value is between 0 and 5 ‰, while the δ13C value is relatively stable during the light period, generally between 2.0 and 3.4 ‰. between. The reason for the significant δ13C change in Sinian seawater is mainly due to the abundance of a large number of marine organisms mainly composed of marine photosynthetic marine flora such as suspected and near-shore algae, the rapid rise of the global marine sedimentation rate, and the deep marine water column In the presence of anoxic layer.