Abstract: The characteristics and formation mechanism of the tectonic schist in the old metamorphic rock series of Bayanwula Mountain,from the study aspects of macrostructure and microstructure.The analysis of microstructural deformation characteristics of quartz and mica minerals show that the brittleductile transition characteristics.The Baiyanwula Mountain tectonic schist is formed by the early nearhorizontal slip structure deformations,and it is experienced the superposition transformation of the mylonitization action formed by the late stage ductile shearing effects.The above analysis results related to the tectonic schist in the old metamorphic rock series of Bayanwula Mountain can provide some reliable reference for the further study on the regional structural characteristics and restoration of regional geological history of the Bayanwula Mountain Area.

Key words: Bayanwula Mountain, Tectonic schist, Formation mechanism