ペロブスキットの電子移行:下層マントルの非コンベクト層の可能性
James Badro1, Jean-Pascal Rueff, György Vankó
1Laboratoire de Minéralogie Cristallographie de Paris (UMR CNRS 7590), Institut de Physique du Globe de Paris, Université Paris, 6 and 7, 4 Place Jussieu, 75252 Paris, France. james.badro@lmcp.jussieu.fr
Science (New York, N.Y.)
|July 17, 2004
まとめ
鉄は鉄で鉄は鉄で
科学分野:
- ミネラル物理学 ミネラル物理学
- 地質化学 地質化学
- 高圧科学とは,高圧科学である.
背景:
- マグネシウムシリケートペロフスキートは,地球の下層マントルの主要な成分です.
- ペロブスキットの鉄のスピン状態は,その物理的,化学的性質に影響します.
- これらの特性を理解することは,地球深層の条件をモデル化するために不可欠です.
研究 の 目的:
- 高圧でマグネシウムシリケートペロブスキートにおける鉄の電子変換を調査するために.
- 下層マントルの条件をシミュレートして,圧力の増加によって鉄のスピン状態がどのように変化するかを決定する.
- これらのスピン移行が地球深層の放射熱伝導性とコンベクションに与える影響を評価する.
主な方法:
- ダイヤモンド・アンビル・セルを使った高圧実験.
- 鉄のスピン状態を測定するための光譜分析.
- 極度の圧力下でのサンプル特性のインシット測定.
主要な成果:
- 70 GPa と 120 GPa で観察された2つの明確な電子移行は,鉄の電子の部分的および完全なスピンペアリングを示しています.
- 低スピン状態の鉄の比率は圧力とともに増加し,マントルの深さの増大と一致する.
- 放射熱伝導性の最大値は,D"層に相当する圧力で観測されました.
結論:
- プレッシャーによって引き起こされるペロブスキットの鉄のスピン移行は,マントルの特性に大きな影響を与えます.
- 最下層のマントルの放射熱伝導性の増加は,非コンベクト層の存在を示唆しています.
- これらの発見は,地球の深い内部の熱伝達と動態を理解するための意味を持つ.
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