The Application Of Gravity Data In Fault Structure Identification And Geologic Body Inference In Abaga

With the rapid development of economy,the demand of society for various mineral resources is increasing day by day.At present,more than 10 mineral resources have been found in the vicinity of Abaga in Xilingol League,Inner Mongolia autonomous region.However,the quaternary system is widely distributed in this area,the basalt cover area is nearly 65%^[1].The widely distributed quaternary has a certain hindrance to the geological survey and prospecting work in this area.The basalt is highly magnetic and will interfere the magnetic field.Therefore,the distribution of geological bodies under the overburden and the distribution of fracture structures cannot be identified reliably by relying solely on the magnetic field characteristics.But gravity data have obvious advantages in this respect^[2].The thesis summarizes the principle and characteristics of existing gravity data processing methods,and USES different methods to process 1:50,000 gravity data in abagaqi region.Use Theta,horizontal direction derivative?0°,45°,90°,135°?,horizontal gradient mode and bouguer gravity anomaly maps,don't fault 85 consensus.The typical fault structures are explained emphatically.By comparison,there are 18faults supported by geological data,accounting for 21.18%of inferred fault structures,which objectively proves the reliability of inferred fault structures by gravity.At the same time,two volcanic craters were inferred,and the inferred results were consistent with the geological data.By means of trend analysis,sliding average,vertical second derivative and wavelet analysis,local anomalies were extracted.Finally,the residual gravity anomaly map obtained by sliding average method is used as the basic graph of local gravity anomaly extraction.Combined with geological and magnetic survey data,a comprehensive study of local gravity anomalies was carried out.Based on the results of local anomaly research,it was concluded that three uplift areas of tongshan formation were all exposed geological bodies.There are 15 uplift areas of niqiuhe formation,including 8 hidden strata,2 semi-hidden strata and 5 exposed areas.There are 7 strata in baoligaomiao formation,among which 4 are exposed,1 is semi-hidden and 2 are hidden.A total of 21 magmatic rocks are inferred in the study area,among which 4 are exposed,6 are semi-hidden and 11 are hidden.Finally,the electrical data such as audio-frequency magnetotelluric method and transient electromagnetic method with controllable source in the research area were collected,and the basalt thickness inferred from the resistivity profile was used as the constraint condition.The gravity data 2.5D inversion method was used to invert the basalt overburden in the research area,and the basalt thickness map was completed.