Abstract We compiled data from studies that examined pairs of compound specific δ13C in both the free- and S-bound fractions of sedimentary organic matter. The studies compiled span a wide range of biomarker type, rock age (∼235 Ma to 3 kyr) and paleo-environments in which the sedimentary organic matter was deposited. Despite this variability, majority of data shows that the S-bound fraction is heavier on average by 2‰ compared with the free HC. The hypotheses of different biological sources and fractionation during sulfurization or maturation of the organic matter are reexamined in light of this result. We conclude that the δ13C fractionation between these two fractions should be a result of a more generalizing mechanism, operating at an early diagenetic stage. Fractionation during biodegradation of the free biomarker fraction can offer such a mechanism. Thus, the S-bound fraction may better represent the original δ13C values of biomarkers used in paleoenvironmental studies. Future studies should confirm this suggested mechanism.

中文翻译：

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硫化作为生物标志物 δ13C 的保存机制

摘要 我们收集了研究数据，这些研究检查了沉积有机质的游离和 S 结合部分中成对的化合物特异性 δ13C。编制的研究涵盖了广泛的生物标志物类型、岩石年龄（~235 Ma 至 3 kyr）和沉积有机质沉积的古环境。尽管存在这种可变性，但大多数数据表明，与游离 HC 相比，S 结合部分平均重 2‰。根据这一结果重新检验了有机物硫化或成熟过程中不同生物来源和分馏的假设。我们得出结论，这两个部分之间的 δ13C 分馏应该是更普遍的机制的结果，在早期成岩阶段运行。游离生物标志物部分的生物降解过程中的分馏可以提供这样的机制。因此，S 结合部分可能更好地代表古环境研究中使用的生物标志物的原始 δ13C 值。未来的研究应该证实这一建议的机制。