最後の氷河期における南極の氷床の千年規模の不安定さ
1Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA. Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA. Lawrence Livermore National Laboratory, Livermore, CA 9.
まとめ
南極の氷床の千年の規模で不安定な出来事は,氷河に流された破片によって特徴付けられ,北大西洋の温暖化と深水の生産の増加と一致しました. これらのエピソードは,西南極の氷棚を不安定化した可能性があります.
科学分野:
- パレオセアノグラフィー
- 気候科学 気候科学
- 氷河学 氷河学とは
背景:
- 深海のコアにある氷河流出廃棄物 (IRD) は,氷山の氷山流出の証拠を提供します.
- 南極の氷床 (AIS) の動態は,世界の海面と海洋循環にとって極めて重要です.
- 北大西洋深水 (NADW) 生産は,世界の海洋循環と気候規制の重要な構成要素です.
研究 の 目的:
- 最後の氷河期における南極の氷床の不安定性と北大西洋の気候の変動性の関係を調査する.
- 炭素同位体を用いて過去の深水循環パターンを再構築する.
主な方法:
- アトランティック南東部の深海コアにおける氷河流出廃棄物 (IRD) 濃度の分析.
- ベンシックフォラミニフェルスの安定同位体分析 (炭素同位体,デルタ(13) C)
主要な成果:
- 南極大陸からのIRD発射のミレニアムスケールパルス発射は,20,000~74,000年前に発生した.
- IRD層は,極地フロントゾーン全体に相関しており,南極の氷床の不安定性が広範囲に広がっていることを示しています.
- 南大西洋のIRDイベントは,北大西洋深水 (NADW) 生産の増加と北大西洋温暖化 (インタースタジアル) と一致しました.
結論:
- 北大西洋の強いインタースタディアルが,南極の氷床の安定性に影響した可能性が高い.
- 海面上昇またはNADWの生産の増加は,西南極の氷棚を不安定化し,ウェッデル海地域の急上昇を引き起こす可能性があります.
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