地球のD'層のアニソトロピーと,MgSiO3のペロブスキート後の相における堆積欠陥

Artem R Oganov¹, Roman Martonák, Alessandro Laio

¹Laboratory of Crystallography, Department of Materials, ETH Zurich, HCI G 515, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland. a.oganov@mat.ethz.ch

|December 24, 2005

まとめ

研究者は,高度なシミュレーションを使用して,地球の最も下層のマントル (D'層) で新しい中間構造を特定しました. これらの発見は,ペロブスキートとポストペロブスキート構造の間の相変化から地震性アニソトロピーがどのように生じるかを明らかにします.

科学分野:

ミネラル物理学ミネラル物理学
ジオダイナミクスは地力学です.
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:

(Mg,Fe) SiO3のペロブスキート後の段階は,地球のD'層における支配的な鉱物である.
その性質は,地震性アニソトロピーや不連続性などの地質学的観測を理解するために極めて重要です.

研究の目的:

ペロブスキートとペロブスキート後の段階の間の中間構造を特定する.
D'層における相変化とプラスチックの変形のメカニズムを解明する.

主な方法:

第一原理のメタダイナミクスを利用し,新しいシミュレーション技術である.
メタダイナミクスの軌道を分析し,相変遷の好ましい経路を決定した.

主要な成果:

中間物質として,低エネルギー多型堆積断層構造を特定した.
{010} をペロブスキートと{110} をポストペロブスキートにおける支配的な滑り平面として決定する.
ペロフスキート後の滑り平面が,観測された地震性アニソトロピーをより良く説明することを示した.

結論:

平面滑りによる断層形成の積み重ねは,相変遷とプラスチックの変形のための重要なメカニズムです.
ポストペロフスキットの滑り平面は,D'層の地震性アニソトロピーを理解する上で極めて重要です.
この発見は,地球の深層マントルの鉱物学と地球物理学のモデルを洗練している.

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