In the Fatira (Abu Zawal) mine area, located in the northern Eastern Desert of Egypt, fieldwork and mineralogical analysis, integrated with machine learning techniques applied to Landsat-8 OLI, ASTER, and Sentinel-2 multi-spectral imagery (MSI) data delineate gold-sulfide mineralization in altered rocks. Gold (Au) anomalies in hydrothermal breccias and quartz veins are associated with NE-oriented felsite dykes and silicified granitic rocks. Two main alteration types are identified: a pyrite-sericite-quartz and a sulfide-chlorite-carbonate assemblage, locally with dispersed free-milling Au specks. Dimensionality reduction techniques, including principal component analysis (PCA) and independent component analysis (ICA), enabled mapping of alteration types. Sentinel-2 PC125 composite images offered efficient lithological differentiation, while supervised classifications, i.e., the support vector machine (SVM) of Landsat-8 yielded an accuracy of 88.55% and a Kappa value of 0.86. ASTER mineral indices contributed to map hydrothermal alteration mineral phases, including sericite, muscovite, kaolinite, and iron oxides. Results indicate that post-magmatic epigenetic hydrothermal activity significantly contributed to the Au-sulfide mineralization in the Fatira area, distinguishing it from the more prevalent orogenic gold deposits in the region. |
