在北冰洋的Gakkel山脊下面的古老,高度异质的地幔
Chuan-Zhou Liu1, Jonathan E Snow, Eric Hellebrand
1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China. chzliu@mail.iggcas.ac.cn
Nature
|March 21, 2008
概括
地球上的耐火领域.
科学领域:
- 地质化学 地质化学
- 海洋学 海洋学 海洋学
- 石化学 石化学是一门学科.
背景情况:
- 海洋山脊地幔被认为是枯竭的,并通过对流而同质化.
- 丰富的部分挑战了这种同质性.
- 阿比索石提供了对地幔过程的洞察力.
研究的目的:
- 调查海洋山脊下方的星球地幔的异质性.
- 确定耐火地幔领域的保存机制.
- 重新评估海洋地幔中奥斯模型年龄的解释.
主要方法:
- 分析了来自Gakkel山脊的耐火深矿石.
- 测量同位素的比率 (187Os/188Os).
- 计算奥斯模型年龄的计算.
主要成果:
- 一些加克尔山脊石表现出高度耗尽的187Os/188Os比率.
- 奥斯模型年龄表明,耐火域的保存年龄高达20亿年.
- 这些古老的领域并没有被中海基岩显著地采样.
结论:
- 耐火域在层中持续存在,挑战通过对流的同质化.
- 在中海山脊下方的上游地幔很可能是异质的.
- 海洋地幔中的奥斯模型年龄要求对大陆石层演变进行谨慎的解释.
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