地球の内部. 地球の内部. 下層マントルの上部で脱水融解
Brandon Schmandt1, Steven D Jacobsen2, Thorsten W Becker3
1Department of Earth and Planetary Science, University of New Mexico, Albuquerque, NM, USA. bschmandt@unm.edu steven@earth.northwestern.edu.
Science (New York, N.Y.)
|June 14, 2014
まとめ
地球のマントルの移行地帯には,深い水の貯蔵庫があるかもしれない. 沈下するマントルはおそらく脱水溶解を引き起こし,660キロメートル以下で水を閉じ込めます.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- ミネラル物理学 ミネラル物理学
- 地震学 地震学とは
背景:
- マントルの移行地帯 (MTZ) は,高い貯水能力を持っています.
- 深層のH2O貯蔵庫は,脱水融解によってマントルの動力学に影響を与える可能性があります.
研究 の 目的:
- MTZから下層マントルへの下流マントルの影響を調査する.
- 深いマントルのプロセスにおける水の役割を決定する.
主な方法:
- マントルの条件をシミュレートする高圧実験室実験.
- マントルのコンベクションと相変化の数値モデリング.
- 密集した北米の地震配列からの地震P-to-S変換の分析.
主要な成果:
- 実験室での実験では,水性リングウッドライトがペロブスキートと (Mg,Fe) Oに変異し,粒子の間の溶融を生成することを示しています.
- 地震データは,660 km 以下の急激な速度低下を明らかにし,推論された下流マントルと相関しています.
- これらの地震観測は,部分的な融解と一致しています.
結論:
- MTZの大部分は水分化されている可能性が高い.
- MTZの下の脱水融解は,過渡地帯に相当量のH2Oを閉じ込めることができます.
- このプロセスは,深水循環とマントルの粘度に影響を及ぼします.
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