Geophysical understandings on deep structure in Yellow Sea

Abstract

Basing on gravity and magnetic data, the wavelet and textural analysis methods are used to analysis the geophysical field features, extract faults information, and calculate magnetic basement in Yellow Sea. Results of new seismic tomography and shallow reflection seismic soundings are taken as the constraint, and three gravity and magnetic profiles are inversed by using generalized method. According to the processing results, we propose that there is a beaded geophysical linear belt in western South Yellow Sea. The belt is NNW trending and we name it South Yellow Sea west marginal fault zone. This fault zone has large extension length and there is great difference in pre-Cenozoic strata of the two sides. It may be the reason why pre-Cenozoic petroleum prospect is different between the land and southern South Yellow Sea Basin. Magnetic basement distribution of Yellow Sea is shallow in the middle, while is deep around, which is consistent with the seismic tomography results. The pre-Cenozoic macro-distribution of residual basin is controlled by local relief of magnetic basement and boundary faults of local structure jointly, which reflects the regularity that local tectonics is controlled by regional tectonics, and shallow structures is controlled by deep structures.