An Integrated Remote Sensing Approach to Lithological Mapping and Critical Raw Material Exploration in the South Portuguese Zone, Spain

The need for effective, economical, and environmentally friendly methods of mineral exploration has grown as worldwide demand for critical raw materials (CRMs) has increased. In this regard, particularly in geologically complex areas, remote sensing provides a quick, non-invasive way to map lithology and assess mineral prospectivity. The potential of Sentinel-2 images for greenfield exploration in the South Portuguese Zone (SPZ) of the Iberian Pyrite Belt, Spain, is assessed in this study. Before analysis, vegetation and water bodies were masked to improve the accuracy of spectral interpretation. The efficacy of remote sensing methods, Band Ratio (BR) and Linear Spectral Unmixing (LSU), in identifying potential zones linked to CRMs and in discriminating lithological units was compared. The outcomes of these approaches were combined to create prospectivity maps for target identification and prioritization of fieldwork areas, and the results were verified using geochemical datasets. The practical contribution of the work is realizing a transferable BR-LSU Sentinel-2 workflow, able to use low-cost satellite observations to get ranked field-check targets. The results show that early-stage mineral exploration can be significantly enhanced by integrating complementary geological and geochemical data with multispectral Sentinel-2 analysis. In complex volcanogenic massive sulfide terrains, the suggested workflow can guide sampling, reduce unnecessary field traverses, lower early-stage exploration costs, and promote more sustainable exploration practices.