使用 Zn/Fe 系统学的弧的氧化还原状态
Cin-Ty A Lee1, Peter Luffi, Véronique Le Roux
1Department of Earth Sciences, Rice University, Houston, Texas 77005, USA.
Nature
|December 3, 2010
概括
原始弧形岩中的与铁的比率 (Zn/Fe(T)) 表明地幔氧化不仅仅是从潜水中产生的. 浅层分化,而不是地幔变化,可能导致弧形岩中较高的氧化状态.
科学领域:
- 地质化学 地质化学
- 石化学 石化学是一门学科.
- 世界地幔地力学地力学
背景情况:
- 弧形岩通常比中海基岩更加氧化.
- 据认为,俯冲将氧化成分引入地幔,导致氧化亚弧地幔.
- 在亚弧地幔中直接确定铁的氧化状态具有挑战性,引发了关于其内在氧化状态的争论.
研究的目的:
- 为了研究弧形岩的地幔源的氧化还原状态.
- 为了确定俯冲是否显著改变了地幔的氧化状态.
- 了解控制弧岩中铁氧化的过程.
主要方法:
- 使用氧化还原敏感的 Zn/Fe (T) 比率作为初级弧形玄武岩及其地幔来源中铁价值状态的代理.
- 在地幔融化和岩分化过程中分析Fe(2+),Fe(3+) 和Zn的行为.
- 在弧形岩石中的Zn/Fe(T) 与中海基岩石进行比较.
主要成果:
- 原始弧形岩石的Zn/Fe(T) 比率与中海基岩相似,表明初级地幔融中的Fe氧化状态相似.
- 在早期的橄素分成过程中,Zn/Fe (T) 的比率保持不变,这意味着中Fe (3+) /Fe (T) 的含量较低.
- 铁的氧化状态 (Fe(3+) /Fe(T)) 增加,磁石稳定只有在渐进的分数结晶后.
结论:
- 氧化地物质的降温可能不会显著改变地幔的氧化还原状态.
- 在弧形岩中观察到的较高的氧化状态可能是浅层岩分化过程的结果.
- 需要进一步的研究才能充分理解这些浅层分化过程.
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