Tectonic background of low grade metamorphic rocks of the Dabie Mountain

Low grade metamorphic rocks on both the northern and southern sides of the Dabie Mountains are important members of subduction orogen of oceanic crust prior to collision between Sino-Korean and Yangtze cratons. The Zhangbaling Group/Mulanshan schist is an oceanic crust prior to Ordovician. Sujiahe Group, Xinyang Group and Foziling Group are trench sediments of Ordovician-Devonian, and constitute an accretionary wedge during subduction. Yangshan coal series and Meishan Group belong to Carboniferous fore-arc sediments and were overthrusted by accretionary wedge during collision. Susong Group are passive continental sediments of the Yangtze craton. Backarc basin sediments are postulated to be concealed by Mesozoic-Cenozoic sediments to the north of the Dabie Mountains. High and ultra-high pressure terranes are exotic tectonic slices exhumed from depth, which are located in low grade metamorphic rocks, and disturb the integrity of the earlier subduction orogen. Subduction happened during Ordovician to Devonian, and collision initiated at the beginning of the Permian.