最も初期のプラネティシマルの後の蓄積は,高度に siderophile 要素によって明らかにされています
Christopher W Dale1, Kevin W Burton, Richard C Greenwood
1Department of Earth Sciences, Durham University, Durham DH1 3LE, UK. christopher.dale@durham.ac.uk
まとめ
コンドリート物質の後期的蓄積は,惑星のマントルに含まれる高度な siderophile 元素 (HSEs) の豊富さを説明する. この過程は,すべての微分体に共通しており,酸化状態がHSE分布を制御している.
科学分野:
- 惑星科学は惑星科学である.
- 地質化学 地質化学
- 宇宙化学 (コスモケミストリー)
背景:
- 陸上の惑星のマントルに含まれる高サイドロフィール元素 (HSE) の豊富さは,コア形成後のコンドリート物質の遅い蓄積によって説明される.
- これまでの研究は,地球,月,火星などの大きな天体に焦点を当てていた.
研究 の 目的:
- 小惑星類の小惑星におけるHSEの豊富性を調査する.
- コンドリート物質の遅い蓄積が微分体の普遍的なプロセスであるかどうかを判断する.
- 惑星マントルのHSE分布を制御する要因を理解する.
主な方法:
- 小惑星質の小惑星質における高度 siderophile element (HSE) の豊富さの分析.
- コンドリート物質とのHSE比の比較.
- HSE分布に対する親体のサイズと酸化状態の影響をモデル化.
主要な成果:
- 小惑星類の小惑星も,高濃度のHSEをコンドリート的な割合で示しています.
- コンドリート物質の遅い蓄積は,広い時間枠 (太陽系形成の5~1億5千万年) にわたって発生した.
- 親体の大きさは,HSEの絶対的多量に影響を及ぼし,酸化状態は,HSEがシリケートマントに混合する主な制御です.
結論:
- コンドリート物質の遅い添加は,すべての異なった惑星とプラネテシマルに共通するプロセスでした.
- 体の酸化状態は,そのシリケートマントルの最終的なHSE含有量を決定する重要な要因です.
- これらのプロセスを理解することで,太陽系の岩石体の初期の進化の洞察が得られます.
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