大气与海洋的氧化开始于23亿年前
Chadlin M Ostrander1,2,3, Andy W Heard4,5, Yunchao Shu4,5
1Department of Geology & Geophysics, University of Utah, Salt Lake City, UT, USA. chadlin.ostrander@utah.edu.
Nature
|June 12, 2024
概括
早期的地球地球.
科学领域:
- 地质化学 地质化学
- 古气候学 古气候学
- 早期地球的历史 历史 历史
背景情况:
- 在古老-原生代过渡后大气氧 (O2) 的上升是复杂的,而不是单一的事件.
- 硫同位素记录表明O2水平波动,直到22亿年前才恢复到无氧条件.
- 在这个时期的海洋氧化动态仍然不太清楚,这阻碍了对行星氧化的完整图像.
研究的目的:
- 研究与大气氧气波动同时发生的海洋氧化动态.
- 将大气中的氧气变化与早期地球海洋的条件联系起来.
- 了解从局部氧气"绿洲"到更广泛的氧化过渡.
主要方法:
- 在南非特朗斯瓦尔超级集团的海洋页岩中分析 (Tl) 同位素比率. 南非特朗斯瓦尔超级集团.
- 在相同的页岩样本中测量氧化还原敏感元素的丰度.
- 对Tl同位素和元素数据与大气氧化的现有硫同位素记录的相关性.
主要成果:
- 较低的authigenic Tl同位素比率 (205Tl/203Tl) 表明氧化氧化被埋在有氧化的海底.
- 较高的氧化还原敏感元素丰度表明,在大气O2上升期间,氧化水扩大了.
- 这些海洋氧化标志在短暂的大气无氧事件中消失了.
结论:
- 在地球早期的氧化还原过渡过程中,海洋和大气的氧化被联系在一起.
- 数据表明,从局部化的"绿洲"式氧化转向更广泛的海洋氧化.
- 这项研究为早期地球的氧化还原史和氧化环境的演变提供了关键的约束.
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