ケノゾイク海水のリチウム同位体史:シリケート気象化と逆気象化の変化
Sambuddha Misra1, Philip N Froelich
1National High Magnetic Field Laboratory, and Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL 32310, USA. sm929@cam.ac.uk
Science (New York, N.Y.)
|January 28, 2012
まとめ
6800万年のリチウム同位体記録は,構造的上昇によって引き起こされる大陸の気象が,海洋化学と気候にどのように影響を与えているかを明らかにしています. この研究は,地質学的力を地球と結びつけています.
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
- イソトープ地球化学 イソトープ地球化学
背景:
- 大陸からの岩石の気象化は大気中の二酸化炭素を消費し,カチオンを海洋に輸送し,海水の化学と地球的な気候に影響を与えます.
- 海水の化学的変化は,構造力の変化を反映しますが,直接的なアーカイブは稀です.
- 海水中のリチウムイソトープ (δ(7) Li(SW)) は,これらの地球の海洋気候プロセスを追跡するための潜在的な代理を提供している.
研究 の 目的:
- 海水のリチウムイソトープの長期 (6800万年) の記録を再構築する.
- 地質学的時間尺度における構造的上昇,大陸の気象,海水の化学の関係を調査する.
- 二酸化炭素の減少の原因と,地球の地質進化との関連を理解する.
主な方法:
- 海洋水のリチウム同位体組成 (δ(7) Li(SW)) の再構築は,プランクトン型フォラミニフェラをアーカイブとして使用しています.
- パレオセーンから現在までの同位体変動の分析.
- 同位体シフトを解釈するために,気象化プロセスと地質学的な影響のモデリング.
主要な成果:
- 6800万年の δ(7) Li(SW の記録は,パレオセーンから現在まで,ミリ (‰) に 9 の上昇を示しています.
- この上昇は,大陸の気象化と海底の逆気象化に大きな変化を示している.
- クレタセウス・パレオゲン間の境界線にわたる δ(7) Li(SW) の顕著な5‰の減少は,衝撃の出来事や火山活動に起因しない大規模な大陸の脱皮を示唆しています.
結論:
- 過去6800万年の間,地質の上昇と大陸の剥落が増加したことで,大陸の気象の強さとCO2の吸収が著しく変化しました.
- 海水のリチウムイソトープは,地形構造,気象,気候の相互作用を理解するための貴重なアーカイブとして機能します.
- クレタセウス・パレオゲン境界の同位体シフトは,地球の地化学サイクルに影響を与える主要な地質学的な出来事を示しています.
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