Time Limit of Dextral Strike-Slip in Cenozoic of Liaodong Bay Section of Tan-Lu Fault Zone
The Tan-Lu Fault Zone has undergone a complex evolutionary process during Cenozoic,and the controversy is mainly focused on the period of the beginning of dextral strike-slip.In this paper,based on various geological and geophysical data and previous research results,taking the Liaodong Bay Section in Bohai Sea as an example,the time limit of dextral strike-slip activity of the Tan-lu fault zone is systematically discussed from both tectonic and sedimentological aspects based on various evidence.The results show that the dextral strike-slip activity of the Liaodong Bay Section of the Tan-Lu fault zone cut and modified the early(Kongdian-the third member of Shahejie formation depositional period)extensional faults,the R-shear fracture was formed in the Late Oligocence Dongying Formation depositional period,and the strike-slip derived structures were mainly developed in the Dongying Formation depositional period until now.The dextral strike-slip activity in the Liaodong Bay Section of the Tan-Lu fault zone staggered the sedimentary bodies formed in Early and Middle Paleogene(Kongdian-Shahejie formation depositional period),and the syndepositional dextral strike-slip activity led to the development and spreading of fish-jumping sand bodies,axial or oblique sand bodies,and the local depression formation controlled by the pressure release effect of bending strike-slip fault.The dextral strike-slip in Cenozoic of the Liaodong Bay Section of the Tan-Lu fault zone was mainly during the depositional period of the Dongying Formation in the Late Oligocene of the Paleogene,and then gradually weakened and continued until now.
dextral strike-slipactivity time limitLiaodong Bay depressionCenozoicTan-Lu fault zonepetroleum geology
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