まとめ
上層マントルの水分含有量は,410キロメートルの地震断絶に大きく影響する. オリヴィンに溶けた水は,オリヴィン相変換に影響を与え,地震波の伝播とマントルの構造に影響を与えます.
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:
- 410キロメートルの地震の不連続は,地球の上層マントルの重要な変化を示しています.
- この不連続性は,主にオリビン (アルファ- ((Mg,Fe) 2SiO4) のベータ- ((Mg,Fe) 2SiO4.4) への相変換に起因する.
- 最近の研究では,水 (H2O) がオリヴィンなどのマントル鉱物に溶けることが示されています.
研究 の 目的:
- オリヴィン相変換に水の影響を調査する.
- H2Oの分割が410kmの深さでの地震の不連続性にどのように影響するかを理解するために.
- 上層マントルの最大水分量を制限するために.
主な方法:
- オリヴィンとベータ相におけるH2O溶解性に関する実験データの分析.
- オリヴィン相移行境界にH2Oの影響をモデル化.
- 地震データを解釈し,410キロメートルの断続性の性質を推測する.
主要な成果:
- 水は,アルファからベータオリヴィン相変換の圧力-温度条件を大幅に変化させます.
- オリヴィンとベータ-Mg,Fe) 2SiO4の間のH2Oの配分係数は約1:10です.
- 観測された地震断絶の幅は,上層マントルのH2O含有量を制限する.
結論:
- オリビンの溶けた水は,410キロメートルの地震断絶の形成に重要な役割を果たしています.
- 地震不連続性の特徴は,上層マントルの水分化状態に制約を与える.
- 上層マントルのオリビンは,H2Oの最大200ppm (重量分) を含んでいる可能性が高い.
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