ゴンドワナの石炭への侵入に関連した海洋無酸素現象の間の二酸化炭素の変化
Jennifer C McElwain1, Jessica Wade-Murphy, Stephen P Hesselbo
1Department of Geology, The Field Museum, 1400 S. Lake Shore Drive, Chicago, Illinois 60605-2496, USA.
Nature
|May 27, 2005
まとめ
海洋無酸素現象 (OAEs) は,炭素循環の変化と関連しています. この研究では,葉のストマタルデータを用いて,マグマの侵入が,メタン水素ではなく,トアルシアンOAEの原因である可能性が高いことを示しています.
科学分野:
- 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
- 地質化学 地質化学
- パレオントロジー・パレオントロジー
背景:
- 海洋無酸素現象 (OAEs) は,有機炭素埋葬の増加,炭素同位体遠征,海洋絶滅によって特徴付けられています.
- トアルシアのOAE (18300万年前) は,おそらくメタンの放出によって引き起こされた,負の炭素同位体の遠征と関連しています.
- トアルシアのOAEの発端に関する2つの仮説は,海洋ガス水合物またはマグマに浸透した有機に富んだ岩石からメタンの放出を含む.
研究 の 目的:
- トルシアンOAEの負の炭素同位体エクスクルッションの因果的メカニズムを調査する.
- トルシアンOAEにおける大気中の二酸化炭素レベルを高解像度で再構築する.
- トルシアンOAE開始のためのガス水素対マグマ侵入仮説をテストするために.
主な方法:
- 過去の大気中の二酸化炭素濃度を決定するために,化石葉のストマタル周波数の分析.
- 海洋および陸上の炭素同位体記録の高解像度地化学分析.
- 世界的な気温変化を推論するための古気候モデリング.
主要な成果:
- 大気中の二酸化炭素レベルは,最初350 ± 100 p.p.m.v.の減少を示し,その後,1200 ± 400 p.p.m.v.の急激な増加を示した. 負の炭素同位体のエクスクールションの間.
- 推論された地球冷却は2.5 ± 0.1°C,その後の温室効果温暖化は6.5 ± 1°Cであった.
- 観測された二酸化炭素の変動は,ガス水素からメタンが放出されるという大惨事と矛盾しています.
結論:
- トアルシアンOAEの初期における大気中の二酸化炭素変化のパターンは,マグマ侵入仮説を支持する.
- この発見は,Karoo-Ferrar doleritesによるゴンドワナ石炭の侵入が,熱生成的なメタンの放出につながり,負の炭素同位素の遠足を引き起こすことを示唆しています.
- この研究は,海洋無酸素現象のトリガーと環境への影響について重要な洞察を提供します.
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