氷河深海の塩分度,温度,デルタ18Oについて
Jess F Adkins1, Katherine McIntyre, Daniel P Schrag
1MS 100-23, Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA. jess@gps.caltech.edu
Science (New York, N.Y.)
|December 3, 2002
まとめ
深海の気温は,最後の氷河期最大期 (LGM) の間,均一であり,凍結点に近いものでした. 温度ではなく塩分が,海洋層分化を引き起こし,南大洋が最も塩分が高く,海平面の推定値に影響を与えた.
科学分野:
- パレオセアノグラフィー
- 気候科学 気候科学
- マリン・ジオケミストリー 海洋地化学
背景:
- 過去の海洋状態を理解することは,気候モデリングに不可欠です.
- 最後の氷河期最大 (Last Glacial Maximum,LGM) は,地球温暖化と海洋循環の変化の重要な期間を表しています.
研究 の 目的:
- LGM中の深海の温度と塩分を復元する.
- この期間の海洋層分化の主要な要因を調査する.
- LGMの海洋条件が,海平面の推定に及ぼす影響を評価する.
主な方法:
- 毛孔液の塩化物濃度と酸素同位体組成の分析.
- 海洋掘削プログラム (ODP) のコアからのデータを活用する.
- 深海の塩分と温度を再構成する.
主要な成果:
- 太平洋,南洋,大西洋の深海の気温は均質で,凍結点に近い.
- 温度よりも塩分量の変動が,氷河期海洋層分化の支配的要因であった.
- 南大洋は,LGMの間に最も高い深海塩分を示し,現代のパターンを逆転させた.
結論:
- LGM深海の条件は,特に塩分度の役割において,現代の海洋と大きく異なっていた.
- 観測された塩分相違によって,変化した極地淡水予算が暗示されています.
- 氷河の塩分量だけでは,淡水貯蔵メカニズムによる世界の平均海面の推定には信頼できないプロキシです.
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