It is not well understood how, in the immediate aftermath of the Sturtian Snowball Earth, marine sulfur cycling resulted in a global distribution of sedimentary pyrite with δ³⁴S values higher than coeval seawater. Here, we analyze the quadruple sulfur isotope systematics of organic-bound sulfur (OS) from the lowermost post-Sturtian Datangpo Formation, South China, and identify two generations of OS formation, each sampling an isotopically distinct sulfate reservoir (δ³⁴S ≈ 26‰ and 52–93‰) that differentially impacted its respective, co-occurring pyrite. Combining several lines of geochemical evidence, we argue that the first OS generation was the product of a sulfate-impoverished meltwater-influenced setting, with OS preservation being the result of resistance to acid hydrolysis. However, the second OS generation was sourced from H₂S produced in sediments during early diagenesis via microbial reduction of a ³⁴S-enriched sulfate pool derived from overlying euxinic or ferruginous seawater. This is the first ancient marine data set where all observed pyrite is more enriched in ³⁴S than its associated OS. Our proposed origin may be applied to global superheavy pyrite (SHP) immediately after the Sturtian and is comparable to processes linked to freshwater-to-marine transitions during rising sea level in the wake of recent glaciation.

目前尚不清楚，在 Sturtian 雪球地球之后，海洋硫循环如何导致 δ ³⁴ S 值高于同时代海水的沉积黄铁矿的全球分布。在这里，我们分析了华南后 Sturtian 大塘坡组最下部的有机结合硫 (OS) 的四硫同位素系统，并确定了两代 OS 地层，每代均采样同位素不同的硫酸盐储层 (δ ³⁴S ≈ 26‰ 和 52-93‰) 对其各自的共生黄铁矿产生了不同的影响。结合几条地球化学证据，我们认为第一代 OS 是受硫酸盐贫乏的融水影响环境的产物，OS 的保存是耐酸水解的结果。然而，第二代 OS 来源于早期成岩作用过程中沉积物中产生的H ₂ S，通过微生物还原从上覆的 euxinic 或含铁海水衍生的富含^{34 S 的硫酸盐池。}这是第一个古代海洋数据集，其中所有观察到的黄铁矿在³⁴S 比其关联的操作系统。我们提出的起源可以在 Sturtian 之后立即应用于全球超重黄铁矿（SHP），并且与最近冰川作用后海平面上升期间与淡水到海洋过渡相关的过程相当。