アフリカと太平洋の下の熱化学構造
Allen K McNamara1, Shijie Zhong
1Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA. allen.mcnamara@asu.edu
Nature
|October 21, 2005
まとめ
地球の潜水の歴史は,深いマントルの構造を形作っています. 数値モデルは,過去のプレート移動が,アフリカと太平洋の下の密集した熱化学堆積を作り,地震観測と一致していることを示しています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 地震学 地震学とは
- 地球科学 地球科学 地球科学
背景:
- アフリカと太平洋の下の下層マントルには,大きな低速の地震異常が存在する.
- これらの異常は,温度変動だけでは完全に説明できない.
- 以前のモデルは,密度の高い熱化学堆積物を示唆したが,幾何学的な検証が欠けていた.
研究 の 目的:
- 地球の潜水の歴史が,地震観測と一致する下層マントルの熱化学構造を生成できるかどうかを調査する.
- 地震学的推論をマントルのコンベクションモデルと調和させる.
主な方法:
- 熱化学コンベクションの数値モデリング.
- 三次元球形の幾何学を用いた.
- 過去1億1900万年のプレート速度を集約した.
主要な成果:
- サブドクションヒストリーは,観測された地震異常に似た形状の熱化学構造を成功裏に生成します.
- 密度の高い物質は,アフリカの下の山頂のような堆積物に集中しています.
- 密度の高い物質の丸い堆積が太平洋の底で形成される.
結論:
- 地球の潜水の歴史は,大規模な下層マントルの構造を形成する重要な要因です.
- モデルは地震学的データと一致し,アフリカと太平洋の異常の異なる形状を説明しています.
- これは,深層マントルの熱化学堆積物の形成のためのメカニズムを提供します.
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