Lithological discrimination and mineralogical mapping using Landsat-8 OLI and ASTER remote sensing data: Igoudrane region, jbel saghro, Anti Atlas, Morocco

Abstract

This study aims to delineate the lithological formations, in addition to a mineralogical mapping comparing between the ASTER and Landsat-8 OLI sensors in the Igoudrane region. The research was accomplished using BR along with spectral profiles of minerals, PCA, MNF, ICA, XRD, and reflectance spectrometry. The BR measured with ASTER revealed the presence of amphibole, illite, smectite, muscovite, phengite, basic degree index SiO2, calcite, chlorite, epidote, dolomite, hydroxides, and ferrous silicates. Furthermore, Landsat-8 OLI BR highlighted areas with oxides, hydroxides, and laterite. The spectral profiles of minerals showed their absorption in the VNIR and SWIR regions. The muscovite and illite (phyllic alteration) are distinguished by Al–OH absorption at 2.20 μm. The argillitic alteration is additionally defined by muscovite, illite, and Kaolinite, where Kaolinite has a high absorption at 0.9 μm. Chlorite and carbonates characterized the propylitic alteration zone, with an absorption ranging between 2.3 μm and 2.35 μm due to CO3 and Mg–OH compositions. The oxidation (hematite and jarosite) was distinguished by absorption near 0.95 μm and 2.3 μm, respectively, whereas the goethite spectral profile exhibits absorption near 1.4 μm and 2.2 μm. The absorption of smectite is 1.4 μm, near 2.2 μm. The amphibole had absorption near 1.4 μm and 2.3 μm, whereas the pyroxene had absorption near 1.4 μm and 2.3 μm. The first three components of PCA, MNF, and ICA showed the highest eigenvalues and gave an appreciable discrimination of the lithologies, especially with ASTER. Moreover, the XRD quantified the mineralogy of the rocks, which were compared to the BR of ASTER. The reflectance spectrometry also provided alteration minerals, such as muscovite, phengite, illite, Fe–Mg chlorite, Fe-chlorite, iron oxides, hydroxides, hornblende, and calcite. Overall, the methodology adopted has shown great performance and strong potential for mapping alteration areas and lithological discrimination in similar arid regions.