在东太平洋下面的地幔中的不对称电气结构在17°S上升
1Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. UMR CNRS 6538, Universite Bretagne Occidentale, Brest, France. Flinders University, Adelaide, South Australia 5042, Australia. Scripps Institution of Oceanography, La Jolla, CA 92093, USA. Toyama University, Toyama 930-8555, Japan. Chiba University, Chiba, Japan. Earthquake Research Institute, University of Tokyo, Tokyo 113, Japan. Geophysics Program AK-50, University of Washington, Seattle, WA 98195, USA.
概括
地幔电磁和断层扫描 (MELT) 实验揭示了东太平洋上升下的不对称地幔电阻. 在山脊以西的较低电阻率表明相互连接的融化,与山脊以东的干地幔不同.
科学领域:
- 地质物理学 地质物理学
- 世界地幔地力学地力学
- 电磁方法 电磁方法
背景情况:
- 东太平洋起 (EPR) 是一个快速扩散的中洋山脊.
- 了解地幔电阻是限制融化分布和地幔组成的关键.
研究的目的:
- 为了研究南太平洋东部升 (EPR) 下地幔的电阻结构.
- 了解与不对称的海底扩散相关的融化分布和地幔过程.
主要方法:
- 磁电电图 (MT) 测量作为地幔电磁和断层扫描 (MELT) 实验的一部分.
- 在上层地幔的电阻变化的分析.
主要成果:
- 在EPR下方观察到一个不对称的地幔电阻结构.
- 在山脊以西发现较低的电阻,表明在150公里内有1-2%的相互连接融分数.
- 在山脊以东的较高电阻率表明一个枯竭的,干燥的橄石地幔 (上100公里).
结论:
- 不对称的地幔电阻与不对称的传播速率和山脊迁移有关.
- 在EPR的两个板块下面存在不同的化生成和运输方式.
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