Abstract: The 1∶50 000 regional geological mapping in the Nanhuatang area, northwestern Hubei, indicates that the northern margin of the Wudang massif underwent two important deformation stages, i.e., extensional detachment along bedding and constricted folding. The former gave rise to a north directed extensional detachment system with 3-4 main detachment surfaces as the framework, while the latter complexed the folds of this system but still followed the kinetic feature of north directed detachment in the early stage. The detachment structure was formed in the late Hercynian Indosinian and is a syncollision extensional structure whose age is consistent with the age of the main orogenic stage of the Qinling orogenic belt.