地球の"D"層におけるMgSiO3のペロブスキート後の段階の理論的および実験的証拠
1Laboratory of Crystallography, Department of Materials, ETH Zurich, Wolfgang Pauli Strasse 10, CH-8093 Zurich, Switzerland. a.oganov@mat.ethz.ch
Nature
|July 23, 2004
まとめ
地球の下層のマントルのマグネシウムシリケートペロブスキートは,D"層の条件下で,ペロブスキート後の段階に変化する. この新しい段階は,最も下層のマントルで観測された不思議な地震特性を説明します.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- ミネラル物理学 ミネラル物理学
- コンピューティング・マテリアル・サイエンス・サイエンス
背景:
- 地球の下層マントルの鉱物学,主に (Mg,Fe) SiO3ペロブスキート,D"層の異常な性質を説明できていない.
- マントルの最下層,約150kmの"D"層は,独特の地震特性を有しています.
研究 の 目的:
- D"層に関連するMgSiO3の高圧,高温の振る舞いを調査する.
- D"層の観測された地震特性を説明できる鉱物相を特定する.
主な方法:
- アブイニシオシミュレーションを使用して,極端な条件下での物質の振る舞いをモデル化します.
- 理論的予測を検証するために高圧実験を行う.
主要な成果:
- MgSiO3は,D"層の圧力と温度でペロブスキートからCaIrO3型のポストペロブスキート構造への相変化を経験します.
- ペロブスキート後の段階の計算された弾性特性は,D"層の地震観測と一致しています.
結論:
- MgSiO3のペロブスキート後の段階は,D"層における支配的な鉱物である.
- この相変遷は地震性アニソトロピーと,D"層の上部にあるシーア波の不連続性を説明する.
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