在关于高喜马拉雅结晶岩系构造演化的研究中，有两个发现引起了地质学家的高度关注：一是高压超高压变质岩所反映的大陆俯冲与折返过程，二是长期困扰地质学家的反转变质带的出露，而关于高喜马拉雅带的演化模型必须同时合理地解释上述两个基本地质现象。本课题立足于在喜马拉雅东段亚东和错那两个剖面上新近发现的高压变质岩石和广泛出露的中压变质岩系，以各期次变质作用P-T-t轨迹、构造变形的改造作用及时代、系统的低温热史为主要约束，首次将高压与中压变质作用结合起来，同时将中压变质与构造变形相结合，构建高喜马拉雅结晶岩系从早到晚的演化过程：早期岩石圈深部俯冲、折返- - 中期中下地壳变质与变形改造过程- - 晚期出露地表，力图以此为基础揭示大陆俯冲折返的过程和反转变质带形成的机制。本项目的实施将不仅为国际上关于喜马拉雅东段高压变质、构造变形与热史演化提供重要的研究数据，还将为喜马拉雅构造演化模式的研究提供新的思路。

Among magnitude important problems that related to the tectonic evolution of the Greater Himalayan Sequence, two interesting findings stimulated widespread attention: the formation of the inverted metamorphism that puzzled lots of geologists for a long time and the exposure of (ultra-)high pressure metamorphosed rocks presenting that the subduction and exhumation of the Indian continent should be involved into the evolution model of the Greater Himalayan Sequence. Generally, an acceptable model should be able to explain the two above mentioned geological findings at the same time. This proposal is established in the newly found high-pressure metamorphosed rocks in Yadong and Cuona districts and wide spread middle pressure metamorphic sequence, for the first time, we conduct combined researches of the high-pressure and middle-pressure metamorphisms, as well as the middle-pressure metamorphism and syn-metamorphic deformation. Based on constraints such as the P-T-t conditions for each phase of the high-pressure and middle-pressure metamorphism, the timing and the alteration of the tectonic deformation on the middle-pressure metamorphism, systematic low-temperature thermochronology, we will set up an integrated tectonic framework for the Greater Himalayan Sequence, which includes the early subduction and exhumation in the lower lithosphere, the later metamorphism and deformation in the middle-lower crust, and the finally denudation and exposure to the surface. In this tectonic framework, we will explain the two basic geological findings mentioned above. The practice of this proposal will not only gather critical research data with regard to the high-pressure metamorphism, tectonic deformation and thermal history for the eastern segment of the Himalyan Orogen, but also improve our considerations when proposing a reliable tectonic evolution model for the Greater Himalayan Sequence.