ジュラ紀の砂丘によって記録される年間モンスーン雨
D B Loope1, C M Rowe, R M Joeckel
1Department of Geosciences, University of Nebraska, Lincoln, Nebraska 68588-0340, USA. dloope1@unl.edu
Nature
|July 14, 2001
まとめ
パンゲアの古代モンスーンの証拠は,ジュラ紀の砂丘の堆積物で見つかりました. 落ち込みの質量は,年間降雨パターンを明らかにし,この期間の極端な季節性を示しています.
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
- 堆積物学 堆積物学 堆積物学 堆積物学 堆積物学
- ストラティグラフィー ストラティグラフィー
背景:
- パンゲア大陸の赤道位置は,パレオゾーイク後期とメソゾーイク初期に位置していた.
- 以前のモデリングとストラティグラフィック研究は,モンスーンの循環と極端な季節性を示唆した.
- 年間降雨頻度に関する直接的な証拠がない.
研究 の 目的:
- パンゲアにおける年間降雨頻度に関する直接的な証拠を提供するためである.
- 史前時代の季節性降雨パターンを再構築するために.
主な方法:
- 年間堆積サイクル内のスランプマスの分析.
- アメリカ南西部のナバホ・サンドストーン・アウトクリップの調査.
- 降雨の季節性を決定するためにスランプポジションの解釈.
主要な成果:
- 砂丘移動の36年の間隔で24のスランプマスを特定しました.
- 夏季季風雨による20回の景気後退を解釈した.
- 冬の嵐による4回の景気後退を解釈した.
結論:
- ジュラ紀の砂丘の傾いた面は,毎年雨が降る事象の史前記録を提供します.
- パンゲア上空におけるモンスーンの循環によって引き起こされる極端な季節性に関する仮説を支持する.
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