Thrust tectonics in the Xinglong coalfield and adjacent areas, northeastern Hebei, China, and its implications for regional tectonics.

Thrust tectonics in the Xinglong coalfield and adjacent areas are characterized by basement-involved thick-skinned thrust tectonics with a typical flat-and-ramp geometry. The volume of displacement along the NNW-verging master thrust fault is estimated to be about 13.1 km and the shallower crustal shortening caused by the thrust and related folding is estimated to be around 32.3%. Based on an analysis of the geometry and kinematics of the thrust tectonics in this area, it is suggested that there is little probability to find a concealed coalfield in the area south of the nearly E-W-trending line from Shenjiahutong to Huangtuliang. The extensively steeply dipping and even overturned features of the strata in the hanging wall and footwaU of the major thrust fault are more easily rationally explained by basement-cored fault-propagation folding, especially by trishear fault-propagation folding model. The cover sequences in the hanging waU and footwaU of the major thrust fault unconformably overlie the crystalline metamorphic-series of the basement. They are completely developed and may be correlated. Neither thrust fault flat developed along the incompetent strata as suggested previously nor evidence for large-scale thrusting deformation has been found in this area. It is proposed that the Xinglong thrust could not serve as the root zone for the Chengde thrust found previously farther northward.