最後の脱氷期における北大西洋西部における放射性炭素の変動
Laura F Robinson1, Jess F Adkins, Lloyd D Keigwin
1California Institute of Technology, MS 100-23, 1200 East California Boulevard, Pasadena, CA 91125, USA. laurar@gps.caltech.edu
まとめ
深海のサンゴからの放射性炭素記録は,脱氷期における水柱の大きな変化を明らかにし,大気中の放射性炭素レベルに影響を与えています. これらの発見は,二極性揺らぎモデルを支持し,深海の変動を極地の気候変化と結びつける.
科学分野:
- パレオセアノグラフィー
- マリン・ジオケミストリー 海洋地化学
- 気候科学 気候科学
背景:
- 過去の海洋循環とその地球気候への影響を理解することは極めて重要です.
- 放射性炭素 (14C) は,海洋循環と年齢の重要なトレーサーである.
- 深海のサンゴとフォラミニフェラは,過去の海洋状態の貴重なアーカイブを提供します.
研究 の 目的:
- 氷河期からホロケーン期までの北大西洋の深い西部の放射性炭素の詳細な歴史を再構築する.
- 海洋放射性炭素の変動,脱氷,大気放射性炭素のレベルとの関係を調査する.
- 深海の古気候記録を用いて,二極性揺れ仮説を検証する.
主な方法:
- 深海のサンゴにおける放射性炭素の分析.
- ペアリングされたベンティックおよびプランクトンフォラミニフェラの分析.
- 放射性炭素年代測定法 放射性炭素年代測定法
主要な成果:
- 脱氷は,放射性炭素濃縮水と放射性炭素濃縮水間のシフトによって特徴づけられ,かなりの水柱のグラデーションを生み出しました.
- 深海の放射性炭素の変動は,大気中の放射性炭素レベルに影響を与えた.
- 深海の記録は,北半球の温暖化と北源の深水形成の増加を結びつける二極性揺れモデルを支持しています.
- 中間/深海の頻度の放射性炭素変動は,極の同期変化と相関していた.
結論:
- 深海の放射性炭素記録は,過去の海洋循環動態とその遠隔接続に関する重要な洞察を提供します.
- この研究は,移行期における地球気候の調節における深海のプロセスの重要性を強化している.
- 証拠は,極地気候のダイナミクスに敏感なカップリングされた海洋-大気系を支持しています.
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