オリゴセン・ミオセンの境界を越えた軌道強制への気候反応
J C Zachos1, N J Shackleton, J S Revenaugh
1Earth Sciences Department, Center for Dynamics and Evolution of the Land-Sea Interface, University of California, Santa Cruz, CA 95064, USA. jzachos@es.ucsc.edu
まとめ
この研究は,ミランコビッチ周期がオリゴセンの終わりからミオセンの初めの気候と海洋化学に影響を与えたことを明らかにしています. 重要な氷河化イベント (Mi-1) は,南極の氷床の膨張を好む珍しい軌道構成と一致しました.
科学分野:
- 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,古代気候学 (paleoclimatology) とは
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
背景:
- オリゴセンの末期からミオセンの初期にかけての気候と海洋の炭素化学は,長期的な気候の動態を理解するために重要である.
- ミランコビッチ周期は,様々な時間スケールで地球の気候に影響を及ぼすことが知られている.
研究 の 目的:
- 気候と海洋の炭素化学のスペクトル特性を550万年以上にわたって分析する.
- 氷河期を含む,軌道変動と気候現象との関係を調査する.
主な方法:
- 西赤道大西洋の深海核のスペクトル分析.
- 550万年 (My) をカバーするクロノロジカル再構築 (My).
- ミランコビッチ周波数における分散の試験. ミランコビッチ周波数における分散の試験.
主要な成果:
- 気候の変動は,すべてのミランコビッチ周波数に集中した.
- 406千年 (ky) の偏心帯 (20−23.4 Ma) の例外的なスペクトルパワー.
- 低温室効果ガス濃度 (21.7-23.0 Ma) の疑いがあるとき,125および95-ky帯の有意なスペクトル電源.
- Mi-1氷河期 (約1年) に発生した 23 Ma) は,軌道一致性 (傾斜ノード,離心率最小) に結びついている.
- 延長された期間 (約. 200 kY) の低季節性軌道が南極の氷の膨張を好む.
結論:
- ミランコビッチ周期は,オリゴセンの終わりからミオセンの初めの気候と海洋の炭素化学に大きな影響を与えました.
- 軌道構成は,Mi-1氷河化のような主要な気候現象を誘発する上で重要な役割を果たしました.
- 低温室効果ガスのレベルは,気候に対する軌道強制を拡大した可能性があります.
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