Research Abstract


Osmium evidence for synchronicity between a rise in atmospheric oxygen and Palaeoproterozoic deglaciation

2011年10月11日 Nature Communications 2 : 502 doi: 10.1038/ncomms1507


関根 康人1, 鈴木 勝彦2,3, 仙田 量子2, 後藤 孝介4, 田近 英一1, 多田 隆治4, 後藤 和久5, 山本 信治4, 大河内 直彦6, 小川 奈々子6 & 丸岡 照幸7

  1. 東京大学大学院 新領域創成科学研究科 複雑理工学専攻
  2. 独立行政法人 海洋研究開発機構 地球内部ダイナミクス領域
  3. 独立行政法人 海洋研究開発機構 プレカンブリアンエコシステムラボラトリー
  4. 東京大学大学院 理学系研究科 地球惑星科学専攻
  5. 千葉工業大学 惑星探査研究センター
  6. 独立行政法人 海洋研究開発機構 海洋・極限環境生物圏領域
  7. 筑波大学 生命環境科学研究科
Early Palaeoproterozoic (2.5–2.0 billion years ago) was a critical phase in Earth's history, characterized by multiple severe glaciations and a rise in atmospheric O2 (the Great Oxidation Event). Although glaciations occurred at the time of O2 increase, the relationship between climatic and atmospheric transitions remains poorly understood. Here we report high concentrations of the redox-sensitive element Os with high initial 187Os/188Os values in a sandstone–siltstone interval that spans the transition from glacial diamictite to overlying carbonate in the Huronian Supergroup, Canada. Together with the results of Re, Mo and S analyses of the sediments, we suggest that immediately after the second Palaeoproterozoic glaciation, atmospheric O2 levels became sufficiently high to deliver radiogenic continental Os to shallow-marine environments, indicating the synchronicity of an episode of increasing O2 and deglaciation. This result supports the hypothesis that climatic recovery from the glaciations acted to accelerate the Great Oxidation Event.