The boundary between the Indian and Asian tectonic plates below Tibet
The boundary between the Indian and Asian tectonic plates below Tibet
复制标题
西藏以下印度板块与亚洲板块的分界线
DOI：
10.1073/pnas.1001921107
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发表时间：
2010-06-22
影响因子：
11.1
通讯作者：
Wang, Wei
中科院分区：
文献类型：
--
作者：
Zhao, Junmeng;Yuan, Xiaohui;Wang, Wei
除了地震层析成像之外，还可以通过绘制深部地震不连续面（如壳幔边界（Moho）、岩石圈-软流圈边界（LAB）或410和660 km深度的不连续面）来可视化青藏高原下印度和亚洲构造板块碰撞的命运。本文介绍了在西藏中西部沿着两条新的剖面上用P和S接收函数技术观测地震不连续面的情况，并与观测到LAB的早期剖面的结果进行了讨论。多条剖面清晰地反映了印度板块和亚洲板块的碰撞边界，表明印度板块和亚洲板块在东西方向上的碰撞方式发生了变化。从东喜马拉雅结到塔里木盆地西缘，印度岩石圈以越来越浅的角度向西藏俯冲，并逐渐向北延伸。青藏高原北方和东部地区形成了一个特殊的岩石圈区域，它是两个板块碰撞的挤压带，其特征是温度高、地幔地震波速度低（与410不连续面的晚到信号相关）、Sn传播差、全球定位系统向东和东南方向的位移以及明显较大的地震（SKS）各向异性。
The fate of the colliding Indian and Asian tectonic plates below the Tibetan high plateau may be visualized by, in addition to seismic tomography, mapping the deep seismic discontinuities, like the crust-mantle boundary (Moho), the lithosphere-asthenosphere boundary (LAB), or the discontinuities at 410 and 660 km depth. We herein present observations of seismic discontinuities with the P and S receiver function techniques beneath central and western Tibet along two new profiles and discuss the results in connection with results from earlier profiles, which did observe the LAB. The LAB of the Indian and Asian plates is well-imaged by several profiles and suggests a changing mode of India-Asia collision in the east-west direction. From eastern Himalayan syntaxis to the western edge of the Tarim Basin, the Indian lithosphere is underthrusting Tibet at an increasingly shallower angle and reaching progressively further to the north. A particular lithospheric region was formed in northern and eastern Tibet as a crush zone between the two colliding plates, the existence of which is marked by high temperature, low mantle seismic wavespeed (correlating with late arriving signals from the 410 discontinuity), poor Sn propagation, east and southeast oriented global positioning system displacements, and strikingly larger seismic (SKS) anisotropy.