Tectonic detachment zone between the Archean basement and the Mesoproterozoic cover rocks in the Qinglong region, eastern Hebei province and its implications

Based on regional mapping, tectonic analyses and distribution of igneous rocks, together with studies on tectonic rocks, we infer that there is a tectonic detachment zone between the Archean basement and the Mesoproterozoic cover rocks in the Qinglong region, eastern Hebei province. This detachment event probably underwent two distinguished periods. The earlier period is characterized by overturned homoclinal folds, and fault gouge and breccia in the detachment zone due to thrust-folding process. The later period shows a detachment process, in which the fault gouge was cleavaged. Determination of the detachment contact between basement and cover rocks is of importance to paleogeographic reconstruction in this region.