マントルの活発な上流の安定性は,プレートテクトニクスの純特性によって明らかにされています
Clinton P Conrad1, Bernhard Steinberger, Trond H Torsvik
1Department of Geology and Geophysics, SOEST, University of Hawaii at Mānoa, Honolulu, Hawaii 96822, USA. clintc@hawaii.edu
Nature
|June 28, 2013
まとめ
地球マントルの流動パターンは,構造板の動きを分析することで明らかになる. この研究は,過去のプレート移動を再構築して,地球深層のダイナミクスを理解し,長期間マントルの上昇を可能にします.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- テクトニクス (地質学) とは
- 地球科学 地球科学 地球科学
背景:
- マントルのコンベクションは,構造板の移動と表面変形を引き起こします.
- 過去のマントルの流れを調査することは,限られた歴史的データのために困難です.
- 表面地質は,地球の歴史を通じて,深いマントルのダイナミクスと密接に結びついています.
研究 の 目的:
- 表面板の動きから地球規模のマントルの流れの時間依存を推論する.
- プレートテクトニクスとマントルダイナミクスの間の歴史的関係を調査する.
- マントルの上流の長期的安定性を特定するために.
主な方法:
- プレート運動の二極と四極の瞬間を計算し,初期のメソゾーイク時代に遡る構造の再構築を用いた.
- ハーモニック度1と2の純収束と分岐の追跡された地理的位置.
- プレート運動の特徴の方向を,マントルの流動パターンと比較した.
主要な成果:
- 現在のプレート運動は,東アジアにおける二極収束と,アフリカ中部と太平洋中部における四極分岐を示している.
- これらのプレート運動の特徴は,マントルの底辺の流れパターンと密接に一致します.
- 四極分岐の位置は,過去2億5000万年にわたって安定したままであり,マントルの上流が持続していることを示唆しています.
結論:
- 表面プレート運動の純特性は,深層マントルの流れパターンの指標として機能する.
- アフリカと太平洋の下の安定したマントルの上流は,マントルの最も下部の異なる地域によって組織されることがあります.
- この研究は,マントルダイナミクスの長期的な進化と地球の表面への影響についての洞察を提供します.
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