Integrated Remote Sensing and GIS Approach for Phosphate Exploration in Eight Documented Areas in Libya

Abstract

Although phosphate deposits have been identified in a number of formations in Libya, their geological controls, spatial distribution, and exploitation potential have not yet been adequately assessed. With an emphasis on the recorded events in Al Fuqaha, Sabha, Idri, Hasi Anjiwal, Tikiumit, Wadi Tanezzuft, Anay, and Gharyan, this study offers a combined remote sensing and GIS-based method for evaluating phosphate prospectivity in Libya. The Sentinel-2 images were processed using the true- and false-colored composites, spectral band rations including B11/B12, B12/B8, and B11/B4, and principal component analysis (PCA) to detect lithological and mineralogical spectral anomalies. The digital elevation model (DEM) helped extract the elevation data, hillshade, slope, lineaments, lineament density, and drainage. The spectral data and detected lithological, geological, and structural were combined, and a weighted-overlay analysis was performed to produce a phosphate prospectivity map. The map was classified into very high, high, moderate, low, and very low potential classes. The phosphate occurrences are primarily controlled by sedimentological and structural factors. The areas that can be considered highly prospective for phosphate exploration were detected, and they are related to the spectral anomalies associated with specific lithology and structural geology. This study proved that multispectral and GIS-based methods are appropriate for regional phosphate exploration in Libya. The detected high and very high prospects need to be prioritized for follow-up geological, geochemical, and mineralogical surveys and, if possible, a drilling campaign.