オリゴセンの初期,北大西洋の深水形成が始まった
R Davies1, J Cartwright, J Pike
1ExxonMobil International Limited, St Catherine's House, 2 Kingsway, PO Box 393, London WC2B 6WF, UK.
Nature
|April 20, 2001
まとめ
北極海と北大西洋の間の深水の流れは,これまで考えられていたよりも早く,約3500万年前に始まった. この発見は,気候変動モデルの影響と,世界の海洋循環の理解に影響を与えます.
科学分野:
- パレオセアノグラフィー
- 気候科学 気候科学
- 地質学 地質学 地質学
背景:
- 北半球の気候モデリングにとって,ケノゾイク期の海洋循環を理解することは極めて重要です.
- グリーンランド・スコットランド・リッジは,歴史的に北極と北大西洋の交流を制限しています.
- フェロー島・シェットランド盆地における深水循環の発生に関する以前の推定は (3500万~1500万年前) 矛盾していた.
研究 の 目的:
- 北極海と北大西洋の間の深水循環の始まりを正確に年代付けするには,北極海と北大西洋の間の深水循環の始まりを正確に年代付けする必要があります.
- この重要な海洋学的な出来事の以前の年齢推定の不一致を解決するために.
- 古代の海洋循環の数値モデルを精査する.
主な方法:
- 南東フェロー島の漂流の発見と分析,120kmの沈殿堆積物.
- 石油探査の掘削穴からのデータを用いて,漂流における堆積の始まりを年代付け.
- 漂流の堆積状態に基づいた古海洋学的条件の解釈.
主要な成果:
- 南東フェロー島の漂流を特定し,古海洋学的特徴の直接的な証拠を提供しました.
- 堆積の始まりは,約3500万年前,オリゴセンの初期にさかのぼります.
- 漂流は南向きの流れで形成され,初期の深水接続を示すことが決定されました.
結論:
- ノルウェー海から北大西洋までの深水循環は,約3500万年前に始まった.
- この始まりは,古代の海洋循環の現在の多くの数値モデルの仮定より前のものです.
- この発見は,古海洋学の再構築と気候モデリングの改訂を必要とします.
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