Lineament and Lithological Mapping of Meta-Sediments and Granitoids of Goz-Beïda (Eastern Chad) Based on Semi-Automatic Processing of Landsat 8 Oli/Tirs Images

Using Lansat-8 OLI/TIR image combined with field and pre-existing data permit us to create lineament and lithological map of Goz-Beïda area. The PCA images were subjected to Sobel directional filters using the semi-automatic extraction method to discriminate lineaments. By combining the 7/5/1 bands in RGB mode, the PCA images (PCA1, PCA2, PCA3) in RGB mode and the ratio bands 7/5, 4/5, 1/7 are used to discriminate the lithological types. The results show that the main lineaments are characterized by NE-SW and NNE-SSW directions. The N-S, ENE-WSW and NW-SE directions correspond to mean directions. Several lithological types are discriminated: two-mica quartzite, metapelite, pyroxene monzonite, biotite granite and two-mica leucogranite. The rocks types are partially covered by alluvial deposits.