古代的氧气绿洲是由海洋中增强循环的脉冲驱动的
Fuencisla Cañadas1, Romain Guilbaud2, Philip Fralick3
1Centro de Astrobiología (CAB), CSIC-INTA, Madrid, Spain.
概括
在地球之前,古代海洋有临时的富含氧气的区域.
科学领域:
- 地质化学 地质化学
- 古海洋学是古海洋学.
- 考古地球历史 地球历史
背景情况:
- 地球的氧化从根本上改变了地球,使复杂的生命成为可能.
- 地化学证据表明,在大气氧化之前,间歇性的海洋氧气绿洲已经存在.
- 驱动早期海洋氧气生产和积累的机制尚不清楚.
研究的目的:
- 重建海洋循环在Archaean海洋.
- 研究循环和氧气生产之间的联系.
- 了解早期海洋氧气绿洲的发展.
主要方法:
- 对氧化还原敏感微量金属和铁物种的分析.
- 相分区分析.相分区分析.
- 研究来自加拿大红湖的2.93亿年前的钻井核心.
主要成果:
- 记录了表面水氧气积累的最早已知的间隔之一.
- 这种氧气积累在大气氧化之前约有5亿年.
- 确定了 ferrous/sulfidic 条件,回收和氧气绿洲之间的联系.
结论:
- 的生物可用性急剧增加刺激了初级生产力和碳埋葬.
- 这一过程很可能控制了亚古纪晚期氧气绿洲的周期性发展.
- 这些绿洲代表了向氧化表面环境的关键过渡阶段.
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