Geophysical Evaluation And Metallogenic Prediction Of YK Copper-lead-zinc Polymetallic Deposit In The Republic Of Congo

The Republic of the Congo(Congo-Brazzaville)has good metallogenic geological conditions,low degree of mining exploration and exploitation,and great potential for resource development.Based on the project of“pre-survey design and geophysical exploration of copper-lead-zinc polymetallic deposit in the Kiori-Hapilo ore belt of the Sorimi YK mining area in Pointe-Noire,Congo-Brazzaville”,this thesis carried out geophysical exploration in YK mining area in Congo(Brazzaville),and delineated the prospect of mineralization.According to the geological characteristics and metallogenic background of the study area,the electrical structure detection and comprehensive evaluation of the mining area are carried out by using three geophysical exploration methods of IP ladder,IP sounding and audio magnetotelluric sounding.Combined with the electrical characteristics of known ore bodies,the metallogenic regularity of copper-lead-zinc polymetallic deposits in this area is systematically summarized.Based on this,the anomalies found in the periphery of the mining area are explained,and the key metallogenic target areas are delineated,which provides a basis for the exploration of copper-lead-zinc polymetallic deposit in YK mining area and achieves the expected goal.The main achievements and understandings of this thesis are as follows:(1)It is preliminarily found that the exposed strata in the abnormal area are the Mopika Group and the Schisto-Calcaire Group of the Western Congo Supergroup,and the lithology is mainly sandstone and dolomite.The wall rock alteration of the ore body is mainly silicification,carbonation,malachite mineralization,pyrite,hematite and limonite.(2)Through the IP ladder scanning,the high value abnormal distribution of apparent polarizability in the study area is found out,and three buried fault structures are deduced according to the apparent resistivity plane map.(3)The IP sounding and EH4 electromagnetic sounding profiles are laid in the key IP anomaly areas.Through the processing and analysis of IP sounding data,the resistivity and polarizability model of two-dimensional inversion of IP sounding profile are obtained.Based on this,the buried depth,occurrence and spatial distribution of polarization anomaly body are understood,and the concealed fault and geological boundary are deduced.It is speculated that the ore body may be located at the bottom of sandstone and the contact area between sandstone and dolomite.The inversion model of audio magnetotelluric sounding profile is compared with the two-dimensional inversion model of IP sounding profile,which verifies the effectiveness of IP method in this area.(4)Through multi-level geophysical exploration methods,combined with regional geological and geophysical data,the geological and geophysical prospecting indicators in the study area are summarized,and three prospecting targets are delineated,which has guiding significance for prospecting in the periphery YK mining area.