Integrated geophysical, remote sensing and geochemical investigation to explore gold-mineralizations and mapping listvenites at Wadi Haimur, Eastern Desert, Egypt

Abstract

Although the continuity of gold mining work since Pharaonic times till today, Wadi Haimur is still promised source for gold. Wadi Haimur is located in west Allaqi-Heinai-Suture (AHS), south Eastern Desert of Egypt. Gold mineralization is mainly confined within quartz-carbonate and sulphide-bearing quartz veins within sheared, altered rocks, while listvenitization plays a significant role in gold concentration along the Haimur area. Therefore, critical analyses of remote sensing data were applied to map alteration zones and delineate listvenites. Spatially enhanced images were processed to trace lineaments and weakness zones which may represent pathways of mineralized, ascended hydrothermal fluids. Ground geophysical, magnetic and geoelectric surveys were performed to study the depth-extension of mineralized bodies in the vicinity of the historical mines within Wadi Haimur. Interpretation of land-magnetic data indicates the presence of mineralized veins associated with narrow shear zones. Derivatives and high-pass filters were utilized to map shallow mineralized sources and deduce their trends. Upward continuation and low-pass filters were used to detect the deep sources. Depths to magnetic bodies were estimated using Power-Spectrum, Euler and inversion of single anomalies. Geochemical sampling was performed to test the results. According to the remarkable variation in resistivity and chargeability values of resistivity and induced-polarization tomography profiles, the subsurface lithology was classified and probable mineralized zones within the subsurface were detected. Encouraging results from regolith, trenching, rock-chip sampling and Reverse-Circulation (RC) drilling indicated the extension of auriferous anomalies within the bedrock. Good correlation of RC-holes auriferous anomalies depths and deduced depths from magnetic interpretation was revealed. HIGHLIGHTS Integrated geophysical, geochemistry and remote sensing data are used to delineate mineralized ore deposits. The estimated average depths of mineralized sources are 12.5, 48 and 463 m for shallow, intermediate and deep magnetic bodies, respectively. Massive sulphide-bearing zones ± gold concentrations were suggested for zones with low-resistivity and high-chargeability signatures.