Abstract Oxygen concentration in the Precambrian atmosphere-ocean system is currently estimated from a series of geochemical proxies that depend on the concentration of redox-sensitive trace elements or their isotopic ratios measured in organic-bearing marine shales. This research has indicated that atmospheric oxygen content throughout the Precambrian was very low, Atmospheric O 2 % = 30 × P / 1 + P Where P = 10 0.89 × log Se/Co + 0.07 , r 2 ; r 2 = 0.85 The oxygen curve revealed by this relationship suggests a broad first-order trend of increasing oxygen of ~0.25 to 27% from 3500 to 1850 Ma, followed by a general decrease to around ~1.0% at ~1000 Ma, with a spike around 1400 Ma. Oxygen then rose gradually through the Ediacaran to reach a maximum of 20 to 29% in the early Cambrian. Detailed analysis of sedimentary pyrite in sixteen separate black shale formations, spaced throughout the Precambrian, demonstrates consistent results using the marine pyrite proxy, with standard deviations of the predicted oxygen for each formation of between 0.4 and 7%. In seven formations, we show that each formation demonstrates an increase in oxygen passing up stratigraphy from the base of the black shale facies toward the top.

中文翻译：

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前寒武纪大气氧升高和变化的证据

摘要 目前，前寒武纪大气-海洋系统中的氧浓度是根据一系列地球化学指标估算的，这些指标取决于在含有机质海相页岩中测量的氧化还原敏感微量元素的浓度或其同位素比率。这项研究表明，整个前寒武纪的大气氧含量非常低，大气 O 2 % = 30 × P / 1 + P 其中 P = 10 0.89 × log Se/Co + 0.07 , r 2 ；r 2 = 0.85 这种关系所揭示的氧曲线表明，从 3500 到 1850 Ma，氧增加约 0.25% 到 27% 的广泛一阶趋势，然后在约 1000 Ma 时普遍减少到约 1.0%，具有峰值约为 1400 Ma。然后氧气通过埃迪卡拉纪逐渐上升，在寒武纪早期达到最高 20% 到 29%。对分布在整个前寒武纪的 16 个独立黑色页岩地层中的沉积黄铁矿的详细分析表明，使用海相黄铁矿代理的结果一致，每个地层的预测氧的标准偏差在 0.4% 到 7% 之间。在七个地层中，我们表明每个地层都表现出从黑色页岩相底部向顶部向上传递的氧气增加。