Primary haematite formation in an oxygenated sea 3.46 billion years ago

Masamichi Hoashi, David C. Bevacqua, Tsubasa Otake, Yumiko Watanabe, Arthur H. Hickman, Satoshi Utsunomiya, Hiroshi Ohmoto

研究成果: ジャーナルへの寄稿学術誌査読

80 被引用数 (Scopus)

抄録

The timing of the origin of photosynthesis on the early Earth is greatly debated. It is generally agreed, on the basis of the presence of biological molecules found in shales from the Hamersley Basin, Australia, that oxygenic photosynthesis had evolved 2.7 billion years (Gyr) ago. However, whether photosynthesis occurred before this time remains controversial. Here we report primary haematite crystals and associated minerals within the marine sedimentary rocks preserved in a jasper formation of the Pilbara Craton, Australia, which we interpret as evidence for the formation of these rocks in an oxygenated water body 3.46 Gyr ago. We suggest that these haematite crystals formed at temperatures greater than 60 C from locally discharged hydrothermal fluids rich in ferrous iron. The crystals precipitated when the fluids rapidly mixed with overlying oxygenated sea water, at depths greater than 200 m. As our findings imply the existence of noticeable quantities of molecular oxygen, we propose that organisms capable of oxygenic photosynthesis evolved more than 700 million years earlier than previously recognized, resulting in the oxygenation of at least some intermediate and deep ocean regions.

本文言語英語
ページ(範囲)301-306
ページ数6
ジャーナルNature Geoscience
2
4
DOI
出版ステータス出版済み - 4月 1 2009

!!!All Science Journal Classification (ASJC) codes

  • 地球惑星科学(全般)

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