Integrated geophysical, mineralogical, and geochemical investigation of gold and associated hydrothermal minerals in the Um Balad Area, Eastern Desert, Egypt

Abstract

Abstract Gold exploration in structurally complex Precambrian terranes remains challenging due to the heterogeneous distribution of hydrothermal alteration zones and the difficulty of distinguishing mineralization-related structures from regional tectonic features. Recent advances in integrated geophysical interpretation have demonstrated the importance of combining multiple datasets to improve structural targeting and hydrothermal mapping within the Arabian–Nubian Shield. The Um Balad area is a promising target for gold and copper exploration, with widespread hydrothermal alteration associated with quartz veins and sulfide mineralization. This study integrates airborne magnetic data, ground gravity surveys, geochemical analyses, and mineralogical investigations to characterize the structural framework and hydrothermal alteration related to mineralization in the area. Gravity and magnetic datasets were processed to delineate lithological boundaries, structural discontinuities, and intrusive bodies associated with hydrothermal activity. Structural interpretation reveals dominant NW–SE, NNW–SSE, E–W, NE–SW, and NNE–SSW fault systems controlling fluid migration and alteration zones. Processing techniques, including radially averaged power spectrum analysis, single-body modeling, and Euler deconvolution were applied to estimate the depth extent of magnetic and gravity sources, indicating both shallow and deep-seated causative bodies. Geochemical and mineralogical analyses were conducted on representative samples from the metagabbro–diorite complex and older granitoids using Spectral Analysis (ASD) and SEM–EDX (Scanning Electron Microscopy combined with Energy Dispersive X-ray Spectroscopy). The identified alteration assemblages include hematite, goethite, muscovite, chlorite, illite, kaolinite, and ferrihydrite. SEM–EDX results indicate significant enrichment in Au, Cu, and Ag, with maximum concentrations of 5.69 wt.% Au, 1.49 wt.% Cu, and 0.22 wt.% Ag. The integration of geophysical, mineralogical, and geochemical datasets demonstrates that structurally controlled hydrothermal alteration zones represent the principal targets for gold mineralization in the Um Balad area.