REGIONAL GEOLOGICAL SETTING, FORMATION AND EXHUMATIONAL MECHANISM OF HIGH-PRESSURE METAMORPHIC BELT IN THE DABIE MOUNTAINS

摘要

Based on geological mapping and careful studies, the authors recognize that the Dabie metamorphic orogen is constituted by bidirectional overturn deformation fold belts between the North China massif and the Yangtze massif and that the fan-shaped and asymmetry structures were formed in the cross section. The high pressure and ultrahigh pressure rocks were formed by the mechanism of "The high pressure pot" in an active area of the longitudianl stretching flow of ductile flow layer between the crust and the mantle boundary. They were driven to the shallow crust under the contraction and compression tectonic system. During the Yianshanian stage and later on, they were raised to the crust surface by the thermal-uplift structures and magmatic intrusion.