增强地幔到地的转移在无气化弧形岩中
Weidong Sun1, Vickie C Bennett, Stephen M Eggins
1School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia.
Nature
|March 21, 2003
概括
深层地球的 (Re) 和 (Os) 储备重新评估. 新的发现显示大陆地中的缩,挑战了地幔-地流的现有地化学模型.
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
- 地球深层的过程.
背景情况:
- 地幔和地幔衍生岩石的Os-187/Os-188同位素特征是地球深层结构的关键标志物.
- 之前的模型表明,深层地幔中有一个长寿的,高成分,可能是海.
- 在地球化学储备中准确的和度对于解释同位素特征至关重要.
研究的目的:
- 重新评估全球预算,通过调查弧型融含物中的度.
- 评估大陆地对全球预算的贡献.
- 修订基于-187/-187衰变系统的地球化学模型.
主要方法:
- 在弧形型融物中分析和 ytterbium 度.
- 在未有气体的弧形岩石中确定Yb/Re比率.
- 将新的地里估计值与以前的值进行比较.
主要成果:
- 在弧形型融内含物中观察到高度和低Yb/Re比率.
- 未脱气的弧形岩石显示出强烈的丰富,表明大陆地中的含量较高 (2 p.p.b.). 比之前估计的要高 (0.4-0.2ppb). ) 的情况.
- 之前在弧形材料中测量的结果可能不准确,因为在下空气喷发样品的脱气过程中,的损失.
结论:
- 大陆地是显著丰富的,与之前的假设相反.
- 从地幔到地的高流需要对地球化学模型进行重新评估.
- 对187Re-187Os衰变系统的解释需要对地球水库中分布的最新估计.
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