Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were used to investigate structural features and hydrothermal alteration zones for mineral exploration in the Precambrian basement of the Bou Azzer–El Graara inlier, located in the Moroccan Central Anti-Atlas. This domain, recognized as a Pan-African suture zone, contains a complex accretionary mélange of arc-related terranes and dismembered supracrustal ophiolites hosting economically significant mineralizations such as Co, Au, and Cu. Its arid setting offers favorable conditions for satellite remote sensing to detect lineaments and alteration patterns indicative of potential metal resources.
To refine structural mapping of the study area, key lineaments were extracted from ASTER data and compared with existing geological interpretations. The identified NE–SW and E–W fault families are consistent with previous tectonic studies, confirming their strong control on the spatial distribution of mineralization. In addition, previously unmapped faults were revealed, requiring further field verification but providing valuable insights into the region’s complex geodynamic evolution. Many of these structures correspond to faults reactivated during the Pan-African, Variscan, and Alpine–Atlas tectonic events.
In the second part of this study, ASTER surface reflectance data were used to map hydrothermal alteration zones through targeted band ratios, enabling the identification of iron oxides, hydroxyl-bearing minerals, sulfates, and carbonates. When combined with available geochemical information, the results show that cobalt anomalies correlate with carbonate–chlorite–epidote alteration, gold anomalies with alunite–kaolinite–pyrophyllite and locally sericite–muscovite–illite–smectite assemblages, and chromium and nickel anomalies with both carbonate–chlorite–epidote and sericite–muscovite–illite–smectite alteration types.
Overall, this integrated approach improves structural and alteration mapping and provides valuable guidance for future mineral exploration in the Bou Azzer–El Graara inlier.
