在夏威夷海浪中,羽毛 - 石质层相互作用的三维模拟
1W. B. Moore and P. J. Tackley, Department of Earth and Space Sciences, University of California, Los Angeles, 3806 Geology Building, Los Angeles, CA 90095-1567, USA. G. Schubert, Department of Earth and Space Sciences and Institute of G.
概括
数字实验表明,更热的地幔羽毛可以为快速的岩层稀释创造不稳定性. 这些由对流滚动驱动的不稳定性,隔离了羽毛,并影响了地球化学异质性.
科学领域:
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
- 地幔动力学地幔动力学
背景情况:
- 石质层稀释对于理解板块构造学和地幔动力学至关重要.
- 之前的数值实验没有通过地幔羽毛实现快速的石质层稀释.
- 有效的稀释需要小规模的不稳定性,以对流方式去除石质层物质.
研究的目的:
- 研究由地幔羽毛引发的快速石层稀释的条件和机制.
- 确定有利于在石质层内发生小规模不稳定的因素.
- 了解羽毛诱导的不稳定性对地幔和岩层异质性的影响.
主要方法:
- 数字实验模拟了地幔羽毛动力学和石质层相互作用.
- 对调度规律的分析,这些规律控制了小规模的对流动不稳定性的出现.
- 将实验结果推断到地球地幔条件.
主要成果:
- 更热的地幔羽毛 (100150 K比背景更热) 促进了与板块运动保持一致的小规模的对流卷.
- 一个简单的缩放定律,独立于质学,控制这些不稳定性的出现.
- 羽毛蔓延形成一个下流的窗,将羽毛从地幔中隔离到1000公里.
结论:
- 通过羽毛驱动的小规模不稳定性,可以实现快速的石质层稀释.
- 鉴定的缩放定律允许将数值发现推断到地球地幔.
- 羽毛隔离对石质层和上层地幔的地化学异质性有重大影响,可能解释像夏威夷海浪这样的特征.
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