The study of tectonic-sedimentation is becoming a main trend of basin research. Jianchang Basin, located at the eastern extension of the intraplate Yanshan orogenic belt, is the typical representation of series of volcanic-sedimentary clastic basins during the Mesozoic. Based on field work and new theories, new methods of tectonic-sedimentation, the paper analyzed the tectonic evolution and sedimentary response of the basin, and discussed the relations between tectonics and sedimentation in Jianchang Basin. On the sedimentary basins, especially continental basins, tectonics are the most dominate factor of the control on its filling sequence. The tectonics has the significant influences to the provenance areas and the space of the sediments. According to the analysis of the relations of tectonic and sedimentation, the evolution of the Jianchang Basin can be divided into three stages: sag basin, flexural basin and unilateral fault basin. Consequently, the specific sediments were found on the basin. The Hekanzi-Nangongyingzi thrust,located at the west of the Jianchang Basin, is a NEN trending fault which formed during the Mesozoic. After analyzing of detailed section and the conglomerate composition variation within of the Early Cretaceous Zhangjiakou Formation in Jianchang Basin,It indicate an erosion and unroofing sequence of the tilted normal sequence of the provenance strata in the hanging wall; the HNTH starting thrusting at the Late Jurassic, and ended before the Ear1y Cretaceous Jiufotang Formation, moved from NW to SE in a piggyback preoperational style. The evolution of fault can be divided into five periods, and the total displacement is more than 25 kilometers.
|