Longmenshan orogen is an intracontinental orogen on the eastern margin of the Xizang plateau. There are three types of tectostratigraphic zones to be recognized in this complicated tectonic collage based on characteristics of deformation, displacement and metamorphism of strata. Zone A, lying between the Qingchuan Maowen fault (F 1) and Beichuan Yingxiu fault (F 2), is a tectostratigraphic zone of deformation and metamorphism and mainly composed of Silurian to Dvernian epmetamorphic rocks and Precambri...