岩石学证据表明,地幔羽毛中出现了长期的冷却
Claude Herzberg1, Esteban Gazel
1Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854-8066, USA. herzberg@rci.rutgers.edu
Nature
|April 3, 2009
概括
海洋岛基岩 (OIB) 和大型火山区 (LIP) 的喷发率不同. 岩石学模型显示,地幔羽毛在过去更热,更广泛地融化,这解释了这些差异.
科学领域:
- 地质化学 地质化学
- 石化学 石化学是一门学科.
- 地质时间学 (Geochronology)
背景情况:
- 海洋岛基岩 (OIBs) 和大型火山区 (LIPs) 的喷发率不同.
- 之前的研究缺乏对OIB和LIP地幔源的温度和融化程度进行定量石油学比较.
研究的目的:
- 为了进行OIB和LIP地幔来源之间的定量石油学比较.
- 为了研究与加拉帕戈斯相关的岩的地幔源温度和融化程度随时间变化的变化.
主要方法:
- 地质绘图和地质时间学研究.
- 在加拉帕戈斯岛相关的岩及其原始岩石中MgO和FeO含量的石化建模.
- 对冰岛长期冷却趋势的分析.
主要成果:
- 与加拉帕戈斯岛相关的岩显示,自白纪以来,MgO和FeO含量有所减少.
- 石油学模型表明,加拉帕戈斯地幔羽毛从1560-1,620°C (白纪) 降温到1500°C (现在).
- 冰岛也显示了世俗冷却的证据.
结论:
- 与较古老的LIP (古世 - 波斯纪) 相关的地幔羽毛比现代OIB更热,更广泛地融化.
- 来自异质的下层地幔领域的插曲性流动可能驱动这些羽毛变化.
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