沟平行异质性是由弧形下层地的化产生的
Mark D Behn1, Greg Hirth, Peter B Kelemen
1Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. mbehn@whoi.edu
Science (New York, N.Y.)
|July 7, 2007
概括
火山弧中的快速地震剪切波速度是由小规模的对流解释的. 这种对流是由密集的弧形下地的沉积驱动的,解决了沟平行异构不一致.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 火山学 火山学是一门学科.
背景情况:
- 火山弧经常表现出与沟冲击平行的地震剪切波速度.
- 这种沟平行异构性挑战了传统的地幔角流量模型.
- 现有的解释,如板块回滚或富含水的橄变形,并不能完全解释观测.
研究的目的:
- 提出一种新的机制来解释火山弧中的沟平行地震异性质.
- 为了使观察到的异质性模式与地质和地物理数据相协调.
- 为无法解释所有观测结果的现有模型提供替代方案.
主要方法:
- 在火山弧中分析地震剪切波速度数据的分析.
- 模拟地幔动力学,包括小规模的对流.
- 模型预测与观察到的异构性模式的比较.
主要成果:
- 小规模的对流,由密集的下弧地的沉积驱动,有效地产生沟平行异构.
- 这种机制解释了异构性,即使在没有板块回滚的直角收设置中也是如此.
- 它为各种火山弧设置中的异构性提供了统一的解释.
结论:
- 密集的下弧地的化和随后的小规模对流是沟平行地震异性质的主要驱动因素.
- 这种机制提供了一个比以前提出的模型更全面的解释.
- 了解这一过程对于解释火山弧下地幔动态至关重要.
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