地質学的制約は,過去300万年の間,潮の消散と地球の動的円性に関するものです
L J Lourens1, R Wehausen, H J Brumsack
1Faculty of Earth Sciences, Utrecht University, The Netherlands. llourens@geo.uu.nl
Nature
|March 10, 2001
まとめ
地球の自転は過去300万年にわたって,低潮流の消散とダイナミックな円性により加速しました. この発見は,天文学的な時間スケールと気候システム研究に影響を与えます.
科学分野:
- 地球科学 地球科学 地球科学
- 天文学 天文学
- 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:
- 太陽系の進化は混沌とし,地球の軌道と precessional motion の再構築を長期的に制限しています.
- 地球の precession, obliquity,およびinsolationは,潮の消散とダイナミックな円性の変動によって影響を受けます.
- これらの変動は,氷河周期とマントルのコンベクションの影響を受けています.
研究 の 目的:
- 過去300万年における潮分散と動的円性の平均値を決定する.
- これらのパラメータが地球の自転と天文時間のスケールに与える影響を評価する.
主な方法:
- 地中海の古気候記録と天文/日照モデルとの間の最適なフィットを計算した.
- 潮分散と動的円性パラメータの様々な値をテストしました.
- 過去の値と,衛星や月の距離測定データから得られた現在の値を比較した.
主要な成果:
- 平均的な動的円度と潮分散は,過去300万年にわたって,現在の値と比較して,著しく低かった.
- この世俗的な変動は,プレオ・プレイストセンの氷の負荷の歴史と関連しており,地球の自転の平均加速を引き起こしました.
結論:
- 過去300万年にわたる減少した消散効果は,地球の自転の観測可能な加速をもたらしました.
- これらの発見は,天文学的時間尺度を構築する際に考慮する必要がある.
- この結果は,海洋気候システムにおける相関の静止性を理解する上で極めて重要です.
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