在大氧化事件期间,有氧细菌酸氧化和酸性岩石排水
Kurt O Konhauser1, Stefan V Lalonde, Noah J Planavsky
1Department of Earth & Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada. kurtk@ualberta.ca
Nature
|October 21, 2011
概括
古代岩石揭示了大约2480亿年前在陆地上 (Cr) 的动员. 这种动员是由有氧细菌和酸性岩石排水驱动的,标志着这些过程的最早的地化学证据.
科学领域:
- 地质化学 地质化学
- 古气候学 古气候学
- 微生物学 微生物学
背景情况:
- 古代海洋岩石中对氧化敏感的微量金属追踪了地球陆地表面的氧化.
- 在前坎布里亚铁层中 (Cr) 的同位素是大气氧化和大陆气候变化的新兴代理物.
- 控制海水Cr同位素组成的因素仍然不太清楚.
研究的目的:
- 为了提供海洋 (Cr) 供应的独立记录,使用Cr度和富含铁的沉积岩中的authigenic丰富.
- 调查与地球氧化历史有关的陆地Cr动员的时间和机制.
主要方法:
- 在富含铁的沉积岩石中分析Cr度和authigenic丰富.
- 在前坎布里亚铁形成中解释Cr同位素组成.
- 与氧化和酸性岩石排水相关的Cr动员通路的建模.
主要成果:
- (Cr) 在陆地上停滞不前,直到大约2480亿年前.
- 在大氧化事件发生后的1.6亿年内,发生了显著的Cr动员,由Cr含量和Cr/Ti比率外游表示.
- 变的Cr同位素分离表明动员主要以减少的Cr (III) 形式.
结论:
- 氧化氧化氧化氧的氧化,chemolithoautotrophic细菌产生酸性,溶解Cr(III) 从超级岩石和土壤.
- 这标志着最早地质化学证据的酸性有机生物和酸性岩石排水,启动了气候变化制度的转变.
- 这种转变解释了海洋中硫酸盐和硫化物托管的微量元素的供应增加,支持一个主要的古老-古老原生代边界地化学和生物过渡.
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