在不同的地幔环境中,金组元素的丰富度模式
1M. Rehkamper, A. N. Halliday, D. Barfod, Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1063, USA. J. G. Fitton and J. B. Dawson, Department of Geology and Geophysics, University of Edinburgh, Edinburgh EH9 3JW, UK.
Science (New York, N.Y.)
|December 5, 1997
概括
团元素 (PGE) 在地幔石中的图案揭示了不同的上层地幔历史. 喀麦隆线外岩表明一个均的地幔,而坦桑尼亚的外岩表明一个丰富的流体,超潜伏区域的起源.
科学领域:
- 地质化学 地质化学
- 石化学 石化学是一门学科.
- 地板的克塞诺石研究研究
背景情况:
- 由地幔衍生的异石为地球上层地幔的组成和演变提供了至关重要的见解.
- 组元素 (PGEs) 是地幔过程的敏感标记物,包括化提取和流体改变.
研究的目的:
- 为了比较组元素 (PGE) 在喀麦隆线和坦桑尼亚北部地幔石中的丰度模式.
- 根据它们的PGE系统学,阐明这两个地区独特的地幔进化历史.
主要方法:
- 在地幔石 (lherzolites和peridotites) 中分析金组元素 (PGE) 度.
- 观察到的PGE模式与已知的地幔储库和地质环境 (例如,ophiolites,suprasubduction区域) 的比较.
主要成果:
- 喀麦隆线石表现出均的PGE图案与状比率,表明一个均的上层地幔.
- 坦桑尼亚的岩石显示了类似于ophiolites的超岩石的PGE模式,这表明了不同的地幔进化.
- 观察到的差异归因于对比的岩层发展:坦桑尼亚的丰富液体的超沉积和喀麦隆线对无水矿石的融化提取.
结论:
- 在喀麦隆线下方的上层地幔被解释为均且大部分无水.
- 坦桑尼亚北部的石质层很可能是在一个富含流体的超潜伏区环境中形成的.
- 在地幔石中PGE的丰富性模式作为各种地幔过程和构造设置的强有力的指标.
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