水性シリケートは高圧で溶けます
Mainak Mookherjee1, Lars Stixrude, Bijaya Karki
1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06511, USA.
Nature
|April 25, 2008
まとめ
水 水 水 水 でした.
科学分野:
- 地質化学 地質化学
- 高圧物理学の高圧物理学
- マテリアルサイエンス 材料科学
背景:
- 地球のマントルの水性シリケート溶解と水溶性の振る舞いは,十分に理解されていません.
- 水は,密度,粘度,低圧での電気伝導性などの溶融特性に大きな影響を及ぼします.
研究 の 目的:
- 高圧下で溶解した水性MgSiO3の構造と性質を調査する.
- マントルの圧力を越えたシリケート溶液における水の種化と混合性を決定するために.
主な方法:
- 第一原理の分子動力学シミュレーションが採用されました.
- シミュレーションは,地球のマントル体制 (136 GPa) まで圧力をカバーしました.
主要な成果:
- 水の種化が分子/ヒドロキシルから圧力が増加するにつれて拡張された構造に変化します.
- 水とシリケート溶融の完全な混合性は,ほとんどのマントルの圧力において観察される.
- 上層マントルの底部で浮力的に安定した溶融は, ~3重%の水を含みます.
結論:
- 高圧は水分の種類を根本的に変化させ,シリケート溶液の混合性を促進する.
- 上層マントルの底部で水分溶解 (~3重%の水) が,電磁波探査によって検出可能であると予測されています.
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