Gold exploration in the Gabal Abu Karahish area, Central Eastern Desert, Egypt: an integrated geological perspective.

This study aims to explore the presence and distribution of gold deposits in the Gabal Abu Karahish area by identifying hydrothermal alteration zones associated with favorable geological settings. The objective is to assess gold potential through an integrated remote sensing and geochemical approach. Multispectral satellite data from ASTER and Landsat-9, combined with radiometric data and field geology, were utilized to delineate alteration zones indicative of mineralization. ASTER band ratios (7/6, 4/6, and 9/8) and Landsat-9 false color composites were processed to enhance lithological discrimination and detect hydrothermal alterations. Automated lineament extraction was also performed to evaluate structural controls on mineralization. Several alteration zones of argillic, phyllic, and propylitic types were identified and are spatially associated with alteration minerals such as chlorite, calcite, kaolinite, sericite, and iron oxides. Scanning electron microscopy (SEM) analysis of ten representative samples from alteration zones and quartz veins in metavolcanic and ultramafic rocks confirmed the presence of gold in all samples, with concentrations ranging from 0.23 to 0.83 g per 50 g of rock powder. These findings highlight key zones for further gold exploration. Geologically, the area is composed of calc-alkaline metavolcanic rocks, Dokhan volcanic rocks, serpentinites, talc carbonates, hornblende gabbros, tonalite, granodiorite, and younger granite intrusions. The lithological diversity and structural features, including listwanite ridges and overthrust contacts, further support the area's mineral potential.