波形断层扫描揭示了海洋天气层底部的道流动
Scott French1, Vedran Lekic, Barbara Romanowicz
1Berkeley Seismological Laboratory, Berkeley, CA 94720, USA.
概括
地质物理学家发现了深层地幔结构,影响了板块构造学和热点火山活动. 几乎周期性的,类似手指的低速度区域延伸到构造板下面,暗示深地幔物质的流入.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 板块构造学是一种板块构造学.
- 地幔动力学地幔动力学
背景情况:
- 地幔对流量和地表地质现象 (如板块运动和热点火山活动) 之间的关系仍然不太清楚.
- 现有的模型很难将深层地幔过程与浅板动态相协调.
研究的目的:
- 为了研究深层地幔结构,驱动板块运动和热点火山活动.
- 了解浅层和深层地幔动态之间的相互作用.
主要方法:
- 全波形地震断层扫描被用于在地球地幔内的剪切速度结构的图像.
- 分析的重点是确定低速度区域及其在不同深度的空间组织.
主要成果:
- 在200-350公里深度之间,以低剪速 (~2000公里波长) 的水平延长,准周期波段被成像,与绝对板块运动对齐.
- 在400公里以下,观测到较少的,波浪状的,垂直连贯的低速度羽毛根植于地幔下部.
- 这些结构延伸在浅浅的低速度区域下面.
结论:
- 这些发现表明,板块驱动的地幔流和来自更深层地幔来源的上游物质之间存在动态相互作用.
- 深层地幔羽毛似乎在移动的岩层下方水平偏移,影响了表面地质.
- 这为推动板块构造和热点形成的机制提供了新的见解.
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