铁质条件主导了后期的新原生代深水化学
Donald E Canfield1, Simon W Poulton, Andrew H Knoll
1Nordic Center for Earth Evolution and Institute of Biology, Campusvej 55, University of Southern Denmark, 5230 Odense, Denmark. dec@biology.sdu.dk
概括
新新生态时代的海洋基本上是无氧和铁质的,这表明古代海洋化学的回归. 这表明氧化在地球历史的这个关键时期是有限的.
科学领域:
- 地质化学 地质化学
- 古海洋学是古海洋学.
- 地球历史 地球历史 地球历史
背景情况:
- 地球的化学环境从无氧转变为氧化条件.
- 新新生态时代 (1000-542亿年前) 是一个关键的过渡时期.
- 原生时代氧化过程的细节尚不清楚.
研究的目的:
- 为了研究海洋无氧的程度和性质,在后期的新新生态时代.
- 了解地球历史上这个关键时期海洋的化学状况.
主要方法:
- 在沉积物记录中分析地质化学代理物.
- 海洋水质量化学的重建.
主要成果:
- 在后期的新新生代 (<742万年前) 中,无氧在海洋混合层下面普遍存在.
- 较深的水有时含有硫化物,但主要是富含Fe2+ (铁).
- 这些条件代表了海洋化学的回归,超过10亿年来没有观察到.
结论:
- 新新生态时期的海洋氧化程度有限,普遍存在无氧和铁状况.
- 这些发现挑战了以前关于这个时代快速氧化的假设.
- 新新生态时期的海洋化学比以前想象的要复杂得多.
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