作为印度与欧亚碰撞的主碰撞带，冈底斯带一直是国际地学关注的焦点，是研究陆陆碰撞过程的最佳场所。最新研究显示印度与欧亚的碰撞结构在冈底斯中部存在巨大的东西向变化，印度板块在91.5°E附近发生了从近水平底侵向高角度俯冲的转换。但是，这种转换是由于印度板块在东构造节俯冲方向变化引起印度岩石圈从西向东逐步后撤引起的，还是由于印度下地壳榴辉岩化产生重力不稳定导致拆沉作用引起的，是研究和理解碰撞过程的重要问题。冈底斯带同时又是重要的成矿带，目前业已发现以驱龙铜矿(17-13Ma)为代表的一批世界级大矿床，其规模之大密集程度之高极为罕见，该问题研究对成矿作用研究也具有重要现实意义。本次申请计划在冈底斯带东部布置60-80个宽频带天然地震台站，采用接收函数和远震层析成像方法揭示印度与欧亚在冈底斯带东部的碰撞结构，通过与前期在冈底斯中部得到的资料进行对比厘清上述问题。

The Gangdese belt is the main collision zone of the India-Eurasia continental collision, and the focus of attention of international geosciences because it is widely considered as the best site to investigate the tectonic process of continental collision. Our most recent results indicate that there is tremendous east-west variation in the lithospheric structure, and a transition from underplating to steep subduction occurs beneath the central Gangdese belt nearby 91.5°E. However, a very important question not addressed yet is why this transition happens, is it due to forces associated with eastward subduction of India beneath Myanmar and the abrupt change in the subduction direction at the eastern syntaxis, or due to the burden of overlying, eclogitized Indian lower crust counteracting its buoyancy? This question is also very important to understand the metallogenic process occurred in the central Gangdese belt, where a large number of world-class deposits have been discovered, for example, the Qulong porphyry copper deposit (dated at 17-13Ma). We want to deploy about 60-80 broadband seismic stations in the eastern Gangdese, to profile the crustal and upper mantle structure of the collision zone in this region, and to address the above question through comparing new results with those obtained in our previous NFSC-founded project.