地球の最も初期の硫黄循環の大気の影響
1Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA. E-mail: jfarquha@ucsd.edu (J.F. ); hbao@ucsd.edu (H.B.); and MHT@chem.ucsd.edu (M.T.).
まとめ
プレキャンブリアス時代の硫黄循環は,2,090~2,450万年前に大きく変化した. この時期以前は,酸素濃度が低いため,微生物の活動ではなく,大気の反応が硫黄循環を支配していた.
科学分野:
- 地質化学 地質化学
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
- 同位体地質学とは,同位体地質学である.
背景:
- 硫黄の循環は,初期の地球条件の重要な指標である.
- 質量独立の硫黄同位体シグネチャー (デルタ:33S,デルタ:34S,デルタ:36S) は,大気中のプロセスに関する洞察を提供します.
- プレキャンブリアス時代の硫黄循環を理解することは,初期の大気組成と生物学的活動を再構築するための鍵です.
研究 の 目的:
- プレカンブリア時代における硫黄循環の進化を調査する.
- 硫黄循環メカニズムにおける重大な変化のタイミングを決定する.
- 硫黄イソトープに対する大気化学と生物学的プロセスの影響を評価する.
主な方法:
- プレカンブリア時代の岩石からの硫化物と硫酸塩の質量独立同位体シグネチャー (デルタ ((33) S,デルタ ((34) S,デルタ ((36) S) の分析.
- 大気および生物学的硫黄変換の文脈で同位体データを解釈するための地球化学モデリング.
主要な成果:
- 2,090~2,450万年前 (Ma) の硫黄循環の大規模な変化の証拠
- 2450万年前には,大気中のガス相反応が硫黄循環に大きく影響した.
- 低大気酸素部分圧が推論され,酸化気象と微生物の硫黄循環を制限しました.
結論:
- プレキャンブリアス期の硫黄循環は,大気反応の優位性から他のプロセスへと移行し,根本的な移行を経験した.
- 微生物の活動ではなく,初期の大気化学は,主に2450万年前に硫黄の同位体分断を制御した.
- 硫黄イソトープを解釈する際には,大気の分断を考慮し,初期の微生物生命と地球の歴史を理解する必要があります.
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