古代末期生物圏の酸素化と大気の進化
Alan J Kaufman1, David T Johnston, James Farquhar
1Departments of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742-4211, USA.
まとめ
25億年前のマックレイ山のシェイルは,古代の酸化硫黄循環を明らかにしています.
科学分野:
- 地質化学 地質化学
- パレオセアノグラフィー
- 初期の地球の歴史 初期の地球の歴史
背景:
- アーケイアエオン (40億年から25億年前) は,地球の大気と海洋の進化にとって重要な時期でした.
- 早期の硫黄循環を理解することは,大酸化イベントに先行した条件を解読する鍵です.
研究 の 目的:
- アーケイアン時代の表面海洋と大気組成の酸化状態を調査する.
- 酸化硫黄循環の活性化のタイミングと範囲を決定する.
主な方法:
- シェールと炭酸塩のサンプルを高解像度地化学分析.
- 堆積岩の硫黄イソトープ分析. 堆積岩の硫黄イソトープ分析. 堆積岩の硫黄イソトープ分析. 堆積岩の硫黄イソトープ分析. 堆積岩の硫黄イソトープ分析. 堆積岩の硫黄イソトープ分析. 堆積岩の硫黄イソトープ分析. 堆積岩の硫黄イソトープ分析.
- 異なる大陸 (オーストラリアと南アフリカ) の間の地質学的記録の相関.
主要な成果:
- マウント・マクレイ・シェイルは,酸化硫黄循環の最初の広範で潜在的に恒久的な活性化を記録しています.
- 硫黄イソトープデータは,大気進化に関連した,外来硫黄サイクルにおける世界的な変化を示唆している.
- 海洋表面の酸素化は,大気中の持続的な酸素化よりも少なくとも5千万年前に起こった.
結論:
- 酸化硫黄循環の活性化は,地球の初期の歴史における重要な世界的な出来事でした.
- 海洋の酸素化は大気中の酸素化に先行し,地球のシステム間の複雑な相互作用を示しています.
- この発見は,アルカイア時代の環境条件に関する重要な洞察を提供します.
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