义敦褶皱区与巴颜喀拉造山带、松潘-甘孜造山带共同构成了我国西部三叠系青藏-滇西褶皱带。把野外地质调查与实验分析相结合，运用现代碎屑岩低温变质理论与方法研究义敦褶皱区三叠系复理石的甚低级变质作用，包括运用黏土矿物学、伊利石结晶度、绿泥石结晶度、层状硅酸盐堆积多型、K云母b0值、碳微区演化、同位素年代学等方法，分析研究复理石变质强度（由IC、CC、多型、矿物组合等表征）的空间变化及其与断裂、褶皱等构造形迹的成因关系，确定变质作用温度变化范围与压力类型，研究区域变质热演化。从而确定造山运动中变质作用的时空范围与强度。研究的完成不仅可解决该区造山过程中存在的变质作用类型之争，完善低温变质作用研究，划分出可与国际对比的变质带；而且可为该区的矿产资源及油气资源的勘探开发提供重要的理论基础。也为西部开发和建设提供基础的地质资料和数据。

The Yidun fold region, the Banyan Har Orogrn and the Songpan-Garze Orogen comprise the Triassic "Qingzang-Dianxi fold belt" in the west of China. This proposal intends to be a continuous study after the NNSFC projects "Very low grade metamorphism of the Triassic flysch in the Songpan-Garze orogen and the Banyan Har orogen" and will focus on the Yidun terrene. The combination of field investigation with laboratory experimental analyses, the theories and methods of low temperature metamorphism will be carried out for this study "very low grade metamorphism of Triassic flysch in the Yidun terrene, Tibetan plateau". Those methods include clay mineralogy, mineral assemblages, international comparable illite crystallinity and chlorite crystallinity, c* domain size, b0 cell-dimensional geobarometry of K-white mica, chlorite geothermometry and evolution of carbonaceous materials as well as Ar-Ar isotopic geochronology. The purposes of this study is to investigate i) the degree of the overprint from diagenesis to metamorphism on the Triassic flysch in the Yidun terrene; ii) the relations between fold axes, faults, strata and boundaries of anchizone and finally iii) to decipher the tectonothermal evolution of the Yidun terrane. It is hopeful also for this proposal to offer useful information for the exploration of oil and gas and for the economic development in the western China.