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华南埃迪卡拉纪陡山沱组的稳定同位素分析显示,从陆架到盆地不同剖面之间的同位素存在明显差异.贵州松林剖面代表了台内盆地沉积,其δ13C值在整个陡山沱组都明显偏负(-3‰～-5‰,VPDB).位于斜坡相的五河剖面也有类似特征(-5‰～-10‰,VPDB).而在瓮安和朵丁两个台地相剖面,陡山沱组的δ13C值大致显示出两个负异常,但叠加了明显的米级变化,而且其δ13C绝对值与华南三峡地区及全球其他地区同时代地层明显不同.这种不同剖面之间的同位素差异,如果在某种程度上代表了古代海水的地球化学特征,则可能记录了陡山沱盆地氧化界面在空间和时间上的不稳定性.综合华南与全球其他埃迪卡拉系地层δ13C数据的分析表明,陡山沱盆地的δ13C变化总体上和埃迪卡拉海洋巨大的溶解有机碳储库的存在和氧化是一致的,但区域环境对新元古代同位素变化也有明显的控制作用.因此,利用δ13C异常作为时间界面进行地层对比需要更加谨慎.
The stable isotopic analysis of the Doushantuo Formation in the Edicarcao Formation in South China shows that there is a significant difference in the isotopes between different sections from the shelf to the basin.The Songlin section of Guizhou Province represents the sedimentation of the inland basin and its δ13C value is obvious throughout the Doushantuo Formation (-3 ‰ ~ -5 ‰, VPDB) .Wuhe profile located in the slope facies also has similar characteristics (-5 ‰ ~ -10 ‰, VPDB), while in the Weng’an and Duoding two platform facies profiles, steep The δ13C value of the Sutuo Formation shows roughly two negative anomalies, but with superficial rice-level variations, and its δ13C absolute value is significantly different from the contemporaneous stratigraphy of the Three Gorges area in South China and other parts of the world. The differences, if somewhat representative of the geochemical characteristics of ancient seawater, may document the spatial and temporal instability of the oxidation interface in the Doushantuo Basin. Combining δ13C data from other Eddahra stratigraphic units in the world The analysis shows that the δ13C variation of the Doushantuo Basin is consistent with the existence and oxidation of the huge dissolved organic carbon reservoir of the Edicala Sea. However, the regional environment has obvious control on the Neoproterozoic isotopic variation. Here, the use of δ13C anomaly stratigraphic correlation need to be more cautious as time interface.