Abstract The emergence and proliferation of metazoan lineage in the Ediacaran Period is commonly hypothesized to reflect an increase in the oxygen content of marine environments. However, recent studies suggest that the Ediacaran oceanic redox conditions were spatially heterogeneous and temporally dynamic. In this study, we report high-resolution pyrite S-isotope data (δ34Spy) for a continuous Ediacaran drill core that was deposited in a very shallow setting from the Yangtze platform, South China. Combined with petrographic observations, statistics of pyrite framboid diameters, total carbon (TC), total sulfur (TS), trace element, and published data, we attempt to characterize the details of sulfur cycle as well as oceanic redox change in the shallow-water regions of the Yangtze platform during the Ediacaran. The δ34Spy profile exhibits a large amplitude of variation, ranging from –13.7‰ to 41.4‰ throughout the drill core. Both global and regional changes in environment could have exerted effects on δ34Spy values. For the Doushantuo Formation, distinct δ34Spy records from shelf to basin may reflect spatial heterogeneity in sulfate concentrations, depositional environments, and availability of organic matter. Notably, periods of upwelling may cause oxygen-deficient zones within shallow water column and facilitate persistent burial of organic matter and pyrite in shelf regions. Subsequent exposure and weathering of these reduced carbon and sulfur may contribute to the “Shuram-Wonoka” event. The prevalence of high δ34Spy values in the terminal Ediacaran (Dengying Formation) likely indicates an enhanced pyrite burial flux at a global scale, during which extensive marine anoxia might take place. In addition, enrichments of V and U in three shale intervals of the drill core support periods of oxygenation for the Ediacaran oceans.

中文翻译：

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华南扬子地台浅水区埃迪卡拉纪硫循环重建与海洋氧化还原演化

摘要 埃迪卡拉纪后生动物谱系的出现和增殖通常被假设为反映了海洋环境中氧含量的增加。然而，最近的研究表明，埃迪卡拉纪海洋氧化还原条件在空间上是异质的，在时间上是动态的。在这项研究中，我们报告了在华南扬子台地非常浅的环境中沉积的连续埃迪卡拉纪钻芯的高分辨率黄铁矿 S 同位素数据 (δ34Spy)。结合岩相观察、黄铁矿小柱状体直径统计、总碳 (TC)、总硫 (TS)、微量元素和已发表的数据，我们试图表征浅水区硫循环的细节以及海洋氧化还原变化埃迪卡拉纪扬子地台地区。δ34Spy 剖面表现出很大的变化幅度，在整个钻芯范围从 –13.7‰ 到 41.4‰。环境的全球和区域变化都可能对 δ34Spy 值产生影响。对于陡山沱组，从陆架到盆地的不同 δ34Spy 记录可能反映了硫酸盐浓度、沉积环境和有机质可用性的空间异质性。值得注意的是，上升流时期可能会导致浅水柱内出现缺氧区，并促进陆架区域有机物和黄铁矿的持久掩埋。这些减少的碳和硫的后续暴露和风化可能会导致“舒拉姆-沃诺卡”事件。埃迪卡拉纪末期（灯影组）高 δ34Spy 值的普遍存在可能表明全球范围内黄铁矿埋藏通量增强，在此期间可能会发生广泛的海洋缺氧。此外，钻芯的三个页岩层段中 V 和 U 的富集支持埃迪卡拉纪海洋的氧化期。