THE RESULTS OF THE 3-D GRAVITATIONAL CALCULUS AND ITS GEOLOGICAL SIGNIFICANCE IN BEIJING - TIANJIN AREA AND THE CENTRAL PART OF HEBEI PROVINCE
liu GuANGXIA, ZHAO WENjUN, WANG JINGYU, WANG ZHEHUI AND REN WENJU(Geophysical Prospecting Brigade, State Seismological Bureau)
The key to deduction of the deep crustal structure using gravity data is (o removing reasonably the influence of shallow layers Authors collected and sorted of the shallow geological data extensively in the studied area, then utilized a 3-D gravitational formula to remove its influence layer by layer and obtainned good results. Results indicate that some structures under the Eogene System basically disappeared and structures of other kinds gradually appeared. It is pointed out that the more complete and accurate shallow geological data are used, the better the results of the 3-D gravitational calculations can be obtained. This method can yield the results that is unified basically with the deep crustal structure inferred from deep seismic sounding. It is also a good and economical way for studying the relationship between shallow and deep structure.