Systematic analysis on microstructures of Shnou mylonite indicated that the quartz are dominated byType II quartz ribbons formed from the recrystallization by both grain-boundary mgraion andprogressive sub-gran rotation, their Cfabrics being Y maxima, slightly transitional towards single girdle.TyPe III quartz ribbons only occurs locally as relics in the weakly mylonitized rocks, where evidences forsinistral shear are also preserved. The feldspars from the mylonite generally display brittle deformation,but some of the K-feldspar grains exhibit some degrees of ductile deformation. Porphyroblasts of garnetare mainly surrounded by the mylonitic foliation. There are also evidences for severa later episodes ofbrittle deformation in the mylonite. Accordingly, the evolulion of the mylonite should be in four stages:(1) Indosinian emplacement of the granitoids, at around 211±8Ma; (2) Early Cretaceous sinistral duchledeformation under amphibolite facies conditions; (3) post-early Cretaceous, man-stape, mylonitizationunder the conditions of middle-to high- greenschist facies metarnorphism, and (4) Late Cretaceous brittledeformation accompanied with the uplift of the region. Systematic analysis on microstructures of Shnou mylonite indicated that the quartz are dominated byType II quartz ribbons formed from the recrystallization by both grain-boundary mgraion and progressive sub-gran rotation, their Cfabrics being Y maxima, slightly transitional towards single girdle. Tepp III quartz ribbons only occurs locally as relics in the weakly mylonitized rocks, where evidences forsinistral shear are also preserved. The feldspars from the mylonite generally display brittle deformation, but some of the K-feldspar grains exhibit some degrees of ductile deformation. Porphyroblasts of garnetare primarily surrounded by the There are also evidences for severa later episodes ofbrittle deformation in the mylonite. There are also evils of the mylonite should be in four stages: (1) Indosinian emplacement of the granitoids, at around 211 ± 8Ma; (2) Early Cretaceous sinistral duchleformation under amphibolite facies conditions; (3) post-early Cretaceous, ma n-stape, mylonitization under the conditions of middle-to-high greenschist facies metarnorphism, and (4) Late Cretaceous brittledeformation accompanied with the uplift of the region.