Late Jurassic basin-fill record of Chengde area in northern Hebei and its tectonic implication

Abstract：Chengde basin in Hebei Province is composed of volcanic rocks of early Late Jurassic Tiaojishan Formation and coarse clastic rocks of middle Late Jurassic-early Early Cretaceous Tuchengzi Formation. Based on a sedimentological study of basin-fill of the Tuchengzi Formation, the authors have reached some conclusions. The northern and southern areas of the Chengde basin were controlled by the Fengning-Longhua thrust faults and Chengde Xian-Jiyuqing thrust faults, respectively. The rapid basin filling process of Chengde basin was the response to the strong intraplate deformation in this period. The intracontinental deformation episode started at the deposition of Tuchengzi Formation and was completed at the end of the deposition. The tectonic deformation process caused Chengde basin to form an asymmetric syncline fold. The age upper limit is constrained by the unconformity beneath volcanic rocks of the Zhangjiakou Formation with the age of 135?1Ma.