Abstract We applied compound-specific sulfur isotope analysis (CSSIA) to organic matter (OM) extracted from ancient and immature organic-rich rocks from the Cretaceous Ghareb (Shefela Basin locality, Israel) and Miocene Monterey (Naples Beach locality, California, USA) Formations. Large variations in the δ34S values of different organosulfur compounds (OSCs), that reach up to 28‰ and 36‰, were observed in the Ghareb and Monterey samples, respectively. Additionally, some common OSCs in both locations showed consistent 34S trends relative to each other. The consistent enrichment in 34S of C35 hopane thiophene relative to iC20 thiophene in the studied sections probably resulted from differences in the timing of OM sulfurization. Reactive organic precursors quickly consume the most 34S-depleted reduced S, while less reactive species incorporate the heavier residual S at a later time. Despite the differences in the depositional environments, ages, and the initial δ34S values of the reduced S (represented by the δ34S of pyrite) between the Ghareb and the Monterey Formations, the sulfurization order of common organic compounds seems to be similar. All of the δ34S values of OSCs are 34S enriched relative to that of the coexisting pyrite with the exception of the C25 highly branched isoprenoid (HBI) thiophene in several samples from the Monterey Formation. The existence of 34S-depleted sulfurized HBI may point to OM sulfurization that occurred at or near the sediment-water interface during the deposition of the Monterey. Moreover, the δ34S of steroid sulfides shows an inverse trend with the pristane/phytane ratio, which may indicate that the sulfurization mechanism of these OSCs are affected by redox conditions. Further investigation of CSSI values in immature rocks from other basins may help constrain the OM sulfurization process, timescale, and depositional conditions and their possible use as paleoenvironmental proxies.

中文翻译：

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未成熟富含有机物岩石中单个化合物的硫同位素组成及其可能的地球化学意义

摘要 我们将化合物特异性硫同位素分析 (CSSIA) 应用于从白垩纪 Ghareb（以色列谢菲拉盆地地区）和中新世蒙特雷（美国加利福尼亚州那不勒斯海滩地区）的古老和未成熟的富含有机物岩石中提取的有机质 (OM)编队。在 Ghareb 和 Monterey 样品中分别观察到不同有机硫化合物 (OSCs) 的 δ34S 值的巨大变化，达到 28‰ 和 36‰。此外，两个位置的一些常见 OSC 相对于彼此显示出一致的 34S 趋势。研究部分中 C35 hopane 噻吩相对于 iC20 噻吩在 34S 中的一致富集可能是由于 OM 硫化时间的差异。反应性有机前体迅速消耗掉最多 34S 的还原 S，而反应性较低的物质会在稍后结合较重的残余 S。尽管 Ghareb 和 Monterey 组之间的沉积环境、年龄和还原 S 的初始 δ34S 值（由黄铁矿的 δ34S 表示）存在差异，但常见有机化合物的硫化顺序似乎相似。相对于共存的黄铁矿，OSC 的所有 δ34S 值都富含 34S，除了来自 Monterey 地层的几个样品中的 C25 高度支化类异戊二烯 (HBI) 噻吩。34S 耗尽的硫化 HBI 的存在可能表明在蒙特雷沉积期间在沉积物-水界面处或附近发生的 OM 硫化。此外，甾体硫化物的 δ34S 显示出与原始烷/植烷比率相反的趋势，这可能表明这些 OSC 的硫化机制受氧化还原条件的影响。进一步研究来自其他盆地的未成熟岩石的 CSSI 值可能有助于限制 OM 硫化过程、时间尺度和沉积条件以及它们作为古环境代理的可能用途。