The Analysis Of Mesozoic- Cenozoic Basin Evolution In The East Area Of Linqing Depression

The fault was the major factor of controlling evolution of the eastern area of Linqing Depression in Mesozoic-Cenozoic. For the characteristic the paper firstly analyzed the activity of faults. According to quantitative analysis of the fault activity, the stage of fault development was divided, further more the characteristics of faults and the original mechanism were studied. In the base of above research and combined the balance cross section, the basin evolution of the work area was discussed. The study result manifests that the characteristics of the faults in the every period were inherited and different and the development of Faults in Mesozoic-Cenozoic were controlled by many Earth dynamic factors, for example, the exterior plate subduction, collision and the interior mantle upwelling, the change of lithosphere structure etc. The evolution of the east area of Linqing Depression in Mesozoic- Cenozoic can be divided into seven stages. From early to middle Triassic, the work area was a part of large-scale interior basin and didn't generate fault. In the Late Triassic the work area was extruded and uplifted undergoing denudation. The early and middle Jurassic was a quiet period of structural activity and the whole work area subsided and sustained sediment. Between late Jurassic and early Cretaceous it was a large half graben controlled by Lanliao Fault. In the late Crataceous, the east area of Linqing Depression was uplifted and denuded because of the effect of the late stage of Yanshan Movement. Early Teriary was a period of big scale development of fault basin. In the south of the work area the trends of most faults were NE and in the north the trends of faults were nearly EW. Most faults developed during the stage of Kongdian Formation and the fourth member of Shahejie Formation; in the stage of second and third member of Shahejie Formation the activity of fault reached maximum; in the stage of the Dongying Formation and the first member of Shahejie Formation and the activity of fault obviously decreased. The activity of some fault was different. The fault controlled the distribution of the structural prototype and depocenter. From Neogene to Quaternary, most faults died out and the work area went into whole downwarp period, the sediment was character of filling-draping.