プロテロゾイク低軌道の傾きと,蒸発した古緯度からの軸対極地磁場
1Department of Geology and Geophysics, 210 Whitney Avenue, Yale University, New Haven, Connecticut 06520-8109, USA. dai.evans@yale.edu
Nature
|November 3, 2006
まとめ
古代の蒸発物質からの古磁気は,過去20億年にわたって地球に安定した軸対極磁場と低軌道傾斜を支えている. これは,プロテロゾイク氷河期の雪球地球仮説を強めている.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 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
- ジオダイナミクスは地力学です.
背景:
- 氷河堆積物や蒸発石のような気候に敏感な岩石における古磁気は,古代の地磁場と古気候地帯をテストする.
- 低地磁気緯度におけるプロテロゾイク期の氷河堆積は,均一主義に挑戦し,スノーボール地球,高傾き,または非均一な地磁気場を示唆しています.
研究 の 目的:
- 過去20億年の地球盆地スケールの蒸発磁気傾き記録をまとめ,分析する.
- 地球の古代の地磁場と軌道パラメータのモデルをテストする.
主な方法:
- 盆地規模の蒸発岩記録からの古磁気データのグローバル・コンパイル.
- 磁気傾斜の分析により,古緯度と地磁場特性を推測する.
主要な成果:
- 蒸発体からの磁気傾きは,低軌道傾きと,過去20億年の大半の期間,地球中心軸二極磁場と一致しています.
- スノーボール地球仮説は,低緯度のプロテロゾーイク氷河期の最も妥当な説明である.
結論:
- この研究は,プロテロゾイク超大陸の再構築のための堅固な地磁気基準フレームを提供します.
- この発見は,地球上のジオダイナモプロセスの安定性を,数十億年の時間スケールで示唆している.
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