地球の下層マントルのスピン移行ゾーン
Jung-Fu Lin1, György Vankó, Steven D Jacobsen
1Lawrence Livermore National Laboratory (LLNL), 7000 East Avenue, Livermore, CA 94550, USA.
Science (New York, N.Y.)
|September 22, 2007
まとめ
鉄は鉄で,鉄は鉄で
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
背景:
- 地下マントルの鉱物特性には,鉄の電子状態が影響する.
- 以前の研究では,代表的な圧力と温度をまだ探求していない.
- フェロペリクラゼは,下層マントルの重要なミネラルです.
研究 の 目的:
- 鉄のスピン状態を低マントルフェロペリクラゼで高圧と高温下で測定する.
- 下層マントルの鉄のスピン移行の地震的影響を理解するために.
主な方法:
- 鉄のスピン状態を測定するために,X線放射光譜を用いた.
- 実験は,レーザーで加熱されたダイヤモンド・アンビル・セルで実施された.
- 95ギガパスカルまでの圧力と2000ケルビンまでの温度を達成しました.
主要な成果:
- フェロペリカラーゼにおける鉄の漸進的なスピン移行が観察されました.
- この移行は,中から下までのマントルに対応する圧力-温度範囲で起こります.
- 低スピンフェロペリクラゼは,高スピンフェロペリクラゼよりも密度が高く,音速が速い.
結論:
- 低スピンフェロペリカラーゼの観測された増加は,マントルの中下部の条件で,スピン移行ゾーンを作成します.
- このゾーンは,正常よりも急な密度グラデントによって特徴付けられます.
- この発見は,地球の深い内部からの地震データを解釈する上で重要な意味を持つ.
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