Geological and Structural Features of Jizhoushan Thrust Nappe in Wutaishan Area, Shanxi Province

Jizhoushan thrust nappe belt is located in the southwestern part of the Mesozoic Yanshan orogenic zone. The thrust nappe belt lies on the northwestern limb of the Jizhoushan syncline with a NEˉstriking axial and occurs during the late period of the late Jurassic. It is composed of a series of nearly parallel thrust faults like plough shape in across section, forming an imbricate arrangement with steep in the front and gentle in the back. The thrust direction of the nappes is mainly southeastward and the slipping distance is more than 5.8 km. The stress during the thrust changed regularly both in horizontal and longitudinal direction. In the basic belt, the main structure is made of highˉangle thrust faults and complex multilevel folds with compression stress. In the middle belt, the stress turned into shearing, and formed imbricate structure. And the recoil fault formed with the compression increasing in the peak belt. Later, the bigger scale normal fault appeared in the foreland with the compression decreasing.