氷河海洋の温度と酸素同位体組成に対する孔腔流体の制約
1D. P. Schrag, Department of Geological and Geophysical Sciences, Princeton University, Princeton, NJ 08544-1003, USA. G. Hampt, Institute of Marine Sciences, University of California, Santa Cruz, CA 95064, USA. D. W. Murray, Department of Geological Sciences, Brown University, Providence, RI 02912, USA.
まとめ
最後の氷河期最大期の間,海洋の温度はより低かった. 熱帯大西洋の毛孔液とフォラミニフェラの酸素同位体の分析は,深水温の4°Cの低下を明らかにし,気候再構築に貢献しています.
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:
- 過去の海洋温度の再構築は,気候の動態を理解するために不可欠です.
- 海洋堆積物や化石の酸素同位体は,過去の気候条件の貴重な代理物として機能します.
- 最後の氷河期最大 (Last Glacial Maximum,LGM) は,地球温暖化の大幅な期間を表しています.
研究 の 目的:
- LGMの間,熱帯大西洋の深い水の温度を測定する.
- 氷の量変化が酸素同位体記録に与える影響を評価する.
- 異なる古気候のプロクシーの間の不一致を調和させるため.
主な方法:
- 深海の堆積物核からの孔状液体における酸素同位体組成 (デルタ18O) の分析.
- ベンシックフォラミニフェラ殻におけるデルタ18Oの測定.
- 毛孔流体とフォラミニフェラのデータを既存の古気候記録と統合.
主要な成果:
- 熱帯大西洋の海水デルタ18Oは,現在と比較して,LGMの間に0.8 ± 0.1 per mil高かった.
- この上昇した比率は,フォラミニフェラルデータと組み合わせて,LGMの間,熱帯大西洋の深海の水温が4°C低かったことを示しています.
- 推定の世界的な氷の量によるデルタ18Oの変化への貢献は,ミリあたり1.0である.
結論:
- 深海の循環と気温は,LGMの間に有意に異なっていた.
- この発見は,古海洋学的データを他の気候プロキシと調和させるのに役立ちます.
- この研究は,過去の氷河期における熱帯大西洋海洋学の理解を洗練します.
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