The sulphur isotopic evolution of Neoarchean and Paleoproterozoic seawater - clues for reconstructing Earth's oxygenation and sulphur metabolism

人们普遍认为，地球的大气和海洋在古元古代早期（大氧化事件- G.O.E.）经历了氧气丰度的大幅增加。进一步证明，大气成分的变化和这一G.O.E.的时间可以受到多个硫同位素测量（32S, 33S, 34S, 36S）的约束，记录了与质量无关的硫同位素分馏。除其他方面外，大气中氧气的增加一定是与海洋硫酸盐丰度的增加并行的。这反过来应该刺激了微生物的硫代谢。海水硫酸盐的硫同位素组成为全球硫循环的变化提供了一个很好的代理。具体来说，海洋硫酸盐的微生物转换是一个与大量同位素分异有关的过程，记录了（34SSO4）的增加。在没有相关数据的情况下，将获得新太古代-古元古代过渡时期海水硫酸盐硫同位素组成的时间记录。为此，将研究来自各自南非演替的碳酸盐中的微量硫酸盐。

It is commonly accepted that Earth s atmosphere and ocean have experienced a substantial increase in oxygen abundance in the early Paleoproterozoic (the Great Oxidation Event - G.O.E.). It has further been demonstrated that changes in atmospheric composition and the timing of this G.O.E. can be constrained by multiple sulphur isotope measurements (32S, 33S, 34S, 36S), recording mass independent sulphur isotope fractionation. Among other aspects, the increase in atmospheric oxygen must have been paralleled by an increase in oceanic sulphate abundance. This in turn should have stimulated microbial sulphur metabolism. The sulphur isotopic composition of seawater sulphate provides an excellent proxy for changes within the global sulphur cycle. Specifically, microbial turnover of oceanic sulphate, a process associated with substantial isotope fractionation, is recorded by an increase in (34SSO4 In the absence of respective data, a temporal record for the sulphur isotopic composition of seawater sulphate through the Neoarchean-Paleoproterozoic transition will be obtained. For this, trace sulphate in carbonates from the respective South African succession will be studied.