富含水的玄武岩在中海山脊的寒冷点
Marco Ligi1, Enrico Bonatti, Anna Cipriani
1Istituto Scienze Marine, Geologia Marina, CNR, Via Gobetti 101, 40129 Bologna, Italy.
Nature
|March 4, 2005
概括
寒冷地区的海洋玄武岩含有惊人的高含水量,挑战了以前的假设. 这一发现表明,富含水的玄武岩不仅在热点附近形成,而且在热点附近也形成.
科学领域:
- 地质化学 地质化学
- 石化学 石化学是一门学科.
- 海洋学 海洋学 海洋学
背景情况:
- 亚洋上层地幔中的水影响着地幔粘度,融化和在中洋山脊上形成地.
- 海洋玄武岩通常含有<0.2%重量%的水,除了那些与"湿"地幔羽毛相关的热点.
研究的目的:
- 调查来自中海山脊系统寒冷区域的玄武岩中异常高含水量的发生和起源.
- 了解富含水的玄武岩在热极小地幔区域的影响.
主要方法:
- 来自赤道大西洋中海系统的玄武岩玻璃的分析.
- 地质化学分析,包括含水量,主要元素 () 和稀土元素的比例.
- 地融过程的数值建模.
主要成果:
- 异常高的含水量检测到来自寒冷的中洋山脊地区的玄武岩玻璃.
- 这些玄武岩富含,具有高光与重稀土元素的比率,表明化过程中存在石榴石.
- 数字建模支持从低度"湿"地幔融在60公里以上的深度的推导.
结论:
- 海洋玄武岩可以在"冷点"中富含水,而不仅仅是在热点附近.
- 这表明,在相当深处的低度"湿"化是产生这些富含水的玄武岩的关键过程.
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