オリヴィン集積物の高切断張力:レオロギー的,地震的影響
M Bystricky1, K Kunze, L Burlini
1Geologisches Institut, ETH-Zentrum, 8092 Zürich, Switzerland. misha@erdw.ethz.ch
Science (New York, N.Y.)
|November 25, 2000
まとめ
高圧実験では,オリヴィン集積物におけるストレスの弱まりが明らかになり,上層マントルの流れに影響を与えています. この地震性アニソトロピーは,再結晶化した岩石の剪定平面の方向性を反映しないかもしれません.
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
- テクトニクス (地質学) とは
背景:
- オリビンの変位は,地球の上層マントルの重要な変形メカニズムです.
- 極端な条件下でのオリビンの行動を理解することは,地力学モデリングに不可欠です.
研究 の 目的:
- 高圧および高温のトルション下でのオリヴィン集積物のストレンス弱化および再結晶化を調査する.
- これらのプロセスの上部マントルの流れと地震性アニソトロピーの影響を評価する.
主な方法:
- オリヴィン集積物の高圧および高温のトルション実験.
- ストレインの弱まり,亜粒線回転再結晶化,および格子型の好ましい方向性の分析.
主要な成果:
- 安定状態の変形前に15-20%のストレスの弱まりが観察されました.
- サブグラン回転再結晶化と強い格子好みの方向性が特定されました.
- 高圧地域における地震波の伝播は,アニゾトロプ的になります.
結論:
- ストレスの弱化は,変形メカニズムを変えることなく,上部マントルの流れを促進する可能性があります.
- 低ストレスのデータに基づいた既存の流れ法則は,高ストレスの地域には不十分かもしれません.
- 高圧,再結晶されたオリビンのアニゾトロピーは,剪定平面の方向性を示さない.
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