弧マグマにおける微量元素の進化の相均衡モデリング:石化生成と銅鉱の指標への影響
Caroline R Soderman1, Owen M Weller1
1Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ UK.
Contributions to mineralogy and petrology. Beitrage zur Mineralogie und Petrologie
|February 19, 2026
まとめ
弧状マグマにおける鉱物溶融のダイナミックな分割は,伝統的な微量元素の解釈に異議を唱える. 新しいモデルでは,高いSr/Y比率が示され,しばしばポルフィール系と関連付けられ,深い水分層だけでなく,様々な条件下で形成されることが示されています.
科学分野:
- 地質化学 地質化学
- ペトロロジー・ペトロロジーとは
- マグマ・ジェネシス
背景:
- 弧状マグマの微量元素比は,ポルフィール形成と不育系を理解する鍵となる.
- 完全な岩のシグネチャーと石油生成条件 (圧力,水,リオックス) の間の定量的なリンクは,分量結晶の過程で進化するミネラルアセンブラージのために困難です.
研究 の 目的:
- 弧マグマにおける微量元素の進化を追跡するための熱力学モデリングフレームワークを開発し,検証する.
- 異なる地殻条件下で微量元素のシグネチャーに起因する動的鉱物溶融分割の影響を調査する.
主な方法:
- ダイナミックな鉱物溶融分割を備えた統合された更新された熱力学モデル.
- アパタイトの飽和度を含む,公表された実験データに対するベンチマークモデル.
- 原始的な弧マグマの微分結晶を模擬して,様々な圧力,水含量,および酸化還元条件で実施した.
主要な成果:
- このモデルは,相組や組成を成功裏に再現しています.
- ダイナミック・パーティショニングにより,アンフィボールとガーネットは,深層で水分のある条件下で,重複する微量元素ベクトルを生成することが明らかになった.
- 一般的なポルファイルの指標である高いSr/Y比は,様々な石油生成経路から生じ,深層,酸化,または水性環境に限定されるものではありません.
結論:
- ダイナミックな鉱物溶融分割は,弧状マグマにおける微量元素の進化に大きく影響する.
- ポルフィール探査のための微量元素比の伝統的な解釈は,再評価を必要とするかもしれません.
- モデリングフレームワークは,弧マグマの石化と微量元素の行動を評価するための強力なツールを提供します.
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