The Analysis of Metamorphism-deformation Sequence for the Paired Metamorphic Belt in West Tianshan Orogen:An Example from Chahanwusu Area, Zhaosu County, Xinjiang

The paired metamorphic belt of West Tianshan Orogen is more typical in Chahanwusu Area, Xinjiang. According to the difference of metamorphism, this paired metamorphic belt can be divided into several metamorphic facies zone, including sericite-chlorite zone with greeanschistfacies, glaucophane zone with greenschist facies,biotite-hornblende zone with amphibolite facies belt and sillimanite-almandite zone with amphibolite facies. Based on the degree of metamorphism and tectonic deformation, this paired metamorphic belt can be divided into three kinds of structural levels:the brittle structural layer in the upper level, the structural layers in the middle-upper level and the ones in the lower level. After analyzing the superimposed relationship among these structural levels, more than threetimes of tectonic deformation characteristics have been distinguished in the rocks of West Tianshan Orogen. And the corresponding metamorphic minerals for these three tectonic stages in the process of deformation can be observed. And then, the interrelationship between generated mineral association and deformation has been discussed, the relationship between metamorphism and deformation sequence has been established according on analyzing the produce order of metamorphic mineral, the rocks' textures and tectonic. Finally, it's certain that the relationship between metamorphism and deformation is not a simple one-to-one relationship, but has the characteristics of penetration superposition and circulation.