东喜马拉雅构造结及周围地区深部三维结构与动力学(EHS3D)-第二阶段

岩石圈的变形方式是青藏高原动力学研究的关键问题之一,其中一个焦点就是要为高原生长过程中产生的大量剩余物质寻找合理的出路，为此人们提出了块体挤出、连续变形、地壳流等多种看法。EHS3D项目试图通过对东构造结及周围地区深部三维结构的研究来寻找上述问题的答案.本项目第一阶段的研究结果揭示出青藏高原东部存在两条环绕东构造结的中下地壳物质流,为三维模型的建立搭起了一个基本框架。本次申请的是EHS3D项目第二阶段的工作.首先, 延长EHS3D-2、3两条测线并增加EHS3D-4测线,求证是否有物质向东北方向流出；其次，通过EHS3D-5测线对地壳流与高原中部的连续性进行确认；第三，通过EHS3D-7测线探寻地壳流进入杨子块体的可能性，以控制东边界。最后，依据MT+LMT观测并结合地质等资料建立研究区的岩石圈三维结构，并研究其流变特性.

Deformation processes of the lithosphere is a key for studying the growth of the Tibetan Plateau.To understand the overal mass balance of the plateau during the collision of Indian and Eurasian plates, many models,such as block extrusion,continuous deformation and crustal flow,have been proposed.EHS3D project is gong to seek the answers of the question by a 3D deep structure model of the Eastern Himalayan Syntaxis and the surroundings.In the Phase I of the EHS3D project,two conductive channels,which were inferred to as the crustal flows in the mid-lower crust around the EHS, have been defined by MT+LMT measurements and a primary frame of the model has been established. This time we are applying the funds for the pahse II of the EHS3D.First,MT+LMT measurements on the entension of EHS3D-2,3 lines and a added line EHS3D-4 to see if any materials flow out from the northeastern margin of the plateau.Secondly,the continuity of the crustal flow from the central of the plateau is to be confirmed by the measurements along line EHS3D-5. Thirdly, to see how the eastern boundary controls the tectonics of the area and if there are any intrusions of the plateau materials into the Yangtz block,MT+LMT soundings along line EHS3D-7 will be carried out. Finally,a comprehensive 3D model will be made and the rheology of the lithosphere is to be explored.