Synergy Of Remote Sensing Data For Mapping The Potential Gold Mineralization Based On GIS Fuzzy Logic Approach

The utilization of multispectral remote sensing satellite imagery to map hydrothermal alteration minerals and structural lineaments is a crucial aspect in the exploration of porphyry and epithermal ore mineralizations,particularly in the OkmaWadi Umm Beckol region where gold mineralization takes the form of epithermal veins and veinlets linked to hydrothermal alteration zones.Thus,the identification of hydrothermal alteration zones is one of the key indicators for targeting new prospective zones of epithermal gold mineralization in the Okma-Wadi Umm Beckol region.In this study,Landsat-8 and Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)multispectral data were processed to recognize different lithological units,extract structural lineament and detect hydrothermal alteration zones in the study area.The main points of this research are as follows:(1)A Fused Color Composite(FCC)image was created using Landsat-8 OLI contrast-enhanced bands 7,5,and 3 in RGB,and another color composite was created using contrast-enhanced bands 7,6,and 5 in RGB to achieve the best lithological enhancement and to recognize different geological unit in the study area.(2)Band ratio and principal component analysis techniques were applied on Lnadsat-8 OLI data to map hydrothermal alteration zones and to extract structural lineament.Advanced argillic,argillic-phyllic,propylitic,and iron oxide alteration zones were detected and discriminated by implementing band ratio and selective PCA to ASTER data.(3)Subsequently,a mineral prospectivity map(MPM)was generated by synthesizing the thematic layers of hydrothermal alteration zones and lineaments using a GIS-based fuzzy logic technique,leading to the prediction of new potential areas for epithermal gold mineralization in the study area.(4)Besides,comprehensive field surveying and laboratory analysis were conducted to verify the remote sensing results and MPM produced by the GIS-based fuzzy logic,42 samples were analyzed for gold detection and 4 samples were precisely studied under a microscope to determine different kinds of alteration which showed a good rate of agreement.The integration of these image processing techniques provides valuable information for the reconnaissance stages of gold exploration at a regional scale,helping exploration geologists to find new gold deposit prospects before conducting costly detailed ground investigations.