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经历了氧丰度的大幅增加（大氧化事件- G.O.E.）。它进一步表明，大气成分的变化和这一G.O.E.可以通过多个硫同位素测量（32 S、33 S、34 S、36 S）来约束，记录质量独立的硫同位素分馏。除其他方面外，大气中氧气的增加一定是由于海洋硫酸盐丰度的增加而引起的。这反过来又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替代指标。具体而言，海洋硫酸盐的微生物周转，一个过程与大量的同位素分馏，记录的增加在（34）SSO 4在相应的数据的情况下，通过新太古代-古元古代过渡的海水硫酸盐的硫同位素组成的时间记录。为此，将研究南非各继承层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.