在中洋山脊玄武岩的构成阶段中,同位素的异质性
Abdelmouhcine Gannoun1, Kevin W Burton, Louise E Thomas
1Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK. a.gannoun@open.ac.uk
概括
中洋基岩 (MORB) 中的放射性同位素变化反映了地幔源差异. 来自MORB矿物质的- (Re-Os) 同位素数据可以揭示结晶年龄和地幔源特性.
科学领域:
- 地质化学 地质化学
- 同位素地球化学 同位素地球化学
- 石化学 石化学是一门学科.
背景情况:
- 中洋脊基岩 (MORB) 呈现放射性同位素变异,通常与地球上层地幔组成有关.
- 在MORB中- (Re-Os) 同位素系统的特点是构成阶段的高Re/Os比率.
- 这导致从187Re衰变中迅速产生放射性187Os.
研究的目的:
- 调查Re-Os同位素系统学在了解MORB源方面的实用性.
- 探索从MORB矿物数据中确定地幔源特征的潜力.
- 建立方法来获得精确的年龄限制和初始的Os同位素值.
主要方法:
- 在MORB.构成矿物中的Re-Os同位素的分析.
- 使用Re-Os系统进行放射测年.
- 解释同位素数据以推断地幔源组成和演变.
主要成果:
- 来自MORB矿物质的Re-Os同位素数据可以提供可靠的结晶年龄.
- 这些数据还揭示了矿物质平衡和同位素交换的细节.
- 从矿物数据中得出的初始的Os同位素值与地幔源属性直接相关.
结论:
- 对MORB矿物质的Re-Os同位素分析对于破译地幔异质性至关重要.
- Re-Os系统提供了一个强大的工具来限制MORB石化和地幔演化.
- 来自Re-Os同位素的精确年龄限制对于明确解释MORB源签名至关重要.
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