まとめ
660キロメートルのマントルの不連続は,ガンマスピネルの分解によって引き起こされます. 新しいレーザーで加熱されたダイヤモンド・アンビル・セル実験は,この移行が地球マントルの圧力で起こることを確認し,地震データを鉱物物理学と調和させています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- ミネラル物理学 ミネラル物理学
- 高圧地化学 高圧地化学
背景:
- 660キロメートルの地震の断絶は,ガンマスピネル (リングウッドライト) がMgSiO3-ペロブスキートとマグネシオウスティートに分解したせいだと考えられている.
- 以前の研究では,この移行が起こる圧力に関する矛盾するデータが提示され,既定のマントルの構成モデルに異議を唱えた.
研究 の 目的:
- マントルの深さ660kmでのガンマスピネルの分解の圧力および温度条件を正確に決定するために.
- 地震観測と鉱物物理学のデータとの660kmの不連続性に関する不一致を解決する.
主な方法:
- レーザーで加熱されたダイアモンド・アンビル・セルを用いたイン・シットーX線 difraktion.
- 圧力,温度,および水静的条件の正確な制御.
- 高圧,高温条件下におけるガンマ-Mg2SiO4相変異の分析.
主要な成果:
- Gamma-Mg2SiO4は,深さ660km (24 GPa, 1,900 K) に相当する圧力と温度まで安定しています.
- 分解産物はMgSiO3-perovskiteとMgO (periclase) として識別されています.
- 実験結果は地震データと一致し,以前の不一致を解決した.
結論:
- 660kmの地震断絶は,地質学的に重要な条件下でガンマスピネルの分解と一致しています.
- 正確な圧力および温度測定は,鉱物物理学と地震学の調和を図る上で極めて重要です.
- 地球のマントルの鉱物学的モデルは,これらの発見によって支持されています.
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