水と潜水地帯のマグマの酸化状態
Katherine A Kelley1, Elizabeth Cottrell
1Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA. kelley@gso.uri.edu
まとめ
マントルの酸素の流動性は,地球にとって極めて重要です.
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
- テクトニクス (地質学) とは
背景:
- マントルの酸素の流動性は,地球の内外質量交換を制御する.
- マントルの酸素の流動性とその進化に影響を与える要因は議論されている.
研究 の 目的:
- マントルの酸素の流動性に関する制御を調査する.
- マントルの酸化状態とテクトニックサイクルを結びつける.
主な方法:
- Fe3+/SigmaFe比の測定は,Fe KエッジマイクロX線吸収近縁構造スペクトロスコーピーを用いたものです.
- バサルトガラスと溶融インクルージョンの噴火前のマグマのH2O含有量の分析.
- 多様なプレートテクトニックの設定でグローバルなサンプリング.
主要な成果:
- マグマのFe3+/SigmaFe比は,潜水地帯に向かって増加する (斜面:0.13-0.17,背面弧:0.15-0.19,弧:0.18-0.32).
- Fe3+/SigmaFe比は,マグマのH2O含有量と線形的に相関する.
- 観測された相関は,スラブから派生した流体の元素トレーサーとリンクしています.
結論:
- 沈殿したプレートからの質量移転は,マントルのを直接酸化する.
- 揮発性物質とスラブ由来液体は,マントルの酸化の主要な原動力である.
- マントル・ケイジのリドックス進化の洞察を提供している.
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