Abstract:

The main structural characteristics of the Bohai Basin is that synsedimentary growth faults widely developed in the basin.These faults are mainly tensile and tenso-shear ones and the structural types includes extensional,strike slip and inversion structures.Great thickness of continental deposits developed in the Meo-Cenozoic Bohai Basin.The Tertiary Period was the principal fault depressed stage.The fourth member of the Shahejie Formation and the Kongdian Formation of the Lower Tertiary scattered incompletely and the basin was small and narrow;She-3 member and the Dongying Formation were distributed extinsively and the basin extended wider.The Upper Tertiary System developed well,the depocenter was formed in the central part of the basin.According to the analysis of structural sedimentary environment,the sedimentry facies of the west of Bohai Basin was controlled by NW directional faults while that of the east region was controlled by NNE directional structures.The major growth index of faults that controlled the the basin indicates that there were three peak stages of fault activities:the Mesozoic,Sha-3 sedimentary stage and Dongying stage.The Sha-3 sedimentary stage was the most intensive stage both for tectonic activities and sedimentation.

Key words: Bohai, Meso-Cenozoic Era, fault structure, sedimentary environment, synsedimentary fault,growth index