Periodic Rifting Activity and Its Controlling on Sedimentary Filling of Paleogene Period in Nanpu Sag

Through analyzing tectonic framework and sequence stratigraphic framework,comparing regional uniform surfaces,Nanpu Sag was compared with other basins in the eastern China,it was sured that strata of Paleogene of Nanpu Sag were related with sedimentary in the third period and fourth period of rifting.On the basis of all of these,it could be divided into 4 sub-periodic subsidence through comparing the scale of uniform of different periodic rifting and volcanic activity periods researching.Meanwhile,characteristics of tectonic activity in different periodic rifting and their controlling on sedimentary filling were studied.Periodic rifting activity in Nanpu Sag could be classified into three periods.Sedimentation process was entirely controlled by boundary fault in the first and second period,sedimentary and subsidence were controlled by stepped-shaped slope belt in steep slope of the eastern Nanpu Sag in the third period,while Gao-liu fault became marginal fault and controlled sedimentary filling in its downing wall in the fourth period.