ピロライトの固体から推論されたコアとマントルの境界の低い温度
Ryuichi Nomura1, Kei Hirose, Kentaro Uesugi
1Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan.
まとめ
地球のマントル固体温は,コアマントル境界付近で驚くほど低い. この発見は,コア-マントルの境界温度の上限を設定し,地球深層のプロセスに関する私たちの理解に影響を与えます.
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
- 惑星科学 惑星科学
背景:
- 地球のマントルの融解温度は,惑星の内部の熱構造を理解するために重要です.
- コア・マントルの境界温度に関する以前の推定は不確実性がある.
研究 の 目的:
- 原始マントルの固体温度を,コアマントルの境界線に関連する高圧で測定する.
- コア-マントル境界 (Core-Mantle boundary, T(CMB)) の温度について,より正確な上限を設定する.
主な方法:
- 地球の深い場所の条件をシミュレートするために高圧実験を行う.
- 三次元X線マイクロトモグラフィー画像を用いて鉱物相を分析する.
主要な成果:
- 原始的な (熱石) マントルの固体温は,コア-マントルの境界圧で3570 ± 200ケルビンまで低くなることが判明しました.
- この低い固体温は,最下層のマントルが全体的に溶かっていないことを意味します.
- T ((CMB) の上限は,最も下層のマントルの広大な領域にペロブスキート後期が存在することを示唆している.
結論:
- 驚くほど低いT ((CMB) は,外部のコアの融解温度が水素などの不純物によって著しく低下することを必要とします.
- これらの発見は,地球の熱的進化と深い内部の組成のモデルを洗練します.
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