The deformation and metamorphic processes of mylonites in the granite-greenstone belt of Seerteng area, Inner Mongolia

Reconstruction of deformation and metamorphic processes and conditions can be carried out by studying micro-features of rock and minerals. This paper has investigated the microstructures, quartz fabrics, and mineral chemistry of mylonites from the ductile shear zone of the granite-greenstone belt in Seerteng area, Inner Mongolia. Synthetic analyses reveal that the mylonites underwent four evolutionary processes of deformation and metamorphism, such as lower-amphibolite facies regional metamorphism, retrograde epidote-amphibolite facies metamorphism and deformation, progressive recrystallization and retrograde greenschist facies metamorphism and deformation. The temperature and pressure combination of four metamorphic stages defines a clockwise p-T path, with the superimposition of a later anticlockwise p-T path.