まとめ
珊瑚年代測定は,アメリカ大西洋沿岸平原における過去50万年の少なくとも5つの温暖期を明らかにしている. これらの間隔間の相対的な海水位は,現在のユースタティック海水位推定値とは異なる.
科学分野:
- 四季地質学 四季地質学
- パレオセアノグラフィー
- 古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
背景:
- 米国大西洋沿岸平原の海洋埋蔵には,貴重な古気候記録が含まれています.
- 過去の海面変動を理解することは,将来の気候変動の影響を予測する上で極めて重要です.
研究 の 目的:
- 米国大西洋沿岸平原の過去の海面と気候条件を再構築する.
- 地域的な海水位データと,世界のeustatic海水位推定値を比較する.
主な方法:
- 化石サンゴのウランシリーズ年代測定.
- オストラコードと花粉のデータを用いた古気候再構築.
- パレオ環境基準に基づいて相対的な海面位置の決定.
主要な成果:
- 過去50万年の間に少なくとも5つの温暖な区間を特定した.
- これらの温暖な間隔の間の相対的な海面位置の再構築 (例えば,188,000年前の+7 +/- 5 m).
- 観測された海面の年代順は,ユースタティック海面の独立した推定値と矛盾しています.
結論:
- 大西洋沿岸平原における地域的な海平面の変化は,世界のユースタティック推定値と一致しません.
- 水位静止調整,石層屈曲,または堆積物下荷などのメカニズムは,不一致を説明する可能性がある.
- クォーターナリーにおける現在のユースタティック海平面の推定値は,改訂が必要になる可能性があります.
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