鉄のプラスチックの変形は,地球の内核の圧力で起こる
1Department of Geology and Geophysics, University of California, Berkeley 94720, USA. wenk@seismo.berkeley.edu
Nature
|July 13, 2000
まとめ
実験によると,鉄の結晶は,変形によって地球の内核に並びます. これは,極端な圧力条件下での地震性アニソトロピーメカニズムの直接的な証拠を提供します.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- マテリアルサイエンス 材料科学
- ミネラル物理学 ミネラル物理学
背景:
- 地球の内核における地震性アニソトロピーは,結晶の並び方を示唆している.
- 以前の研究では様々なメカニズムが提案されたが,コアプレッシャーでの実験的検証が欠けていた.
研究 の 目的:
- 地球のコアの圧力条件下で鉄の弾性およびプラスチック性変形メカニズムを実験的に決定する.
- 内核における地震性アニソトロピーの原因を調査する.
主な方法:
- ダイヤモンド・アンビル・セルにおける軸性ストレスの下にある鉄のシンクロトロンX線 difrraction測定.
- 地球の核に相当する極端な圧力条件をシミュレートします.
主要な成果:
- エプシロン-鉄 (六角的に密集した) 結晶は,圧縮方向に平行なc軸で強い好ましい方向性を示した.
- 観察された結晶の整列は,ポリクリスタル可塑性理論における一次または二次的滑りシステムとしての基礎滑りと一致しています.
結論:
- この研究は,地球の内核で発生する変形機構の直接的な実験的証拠を提供します.
- 物質のレオロギーを極度の圧力下で調査するための新しい実験室の方法が導入されました.
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