Identification of alteration zones using remote sensing lineaments; Optic and radar images in the case of the departments of Abtouyour and Guéra (central massif of Chad)

This work concerns the extraction of lineaments likely to control mineralization from OLI 2 (Landsat 9) and Palsar satellite images. The lineaments were first extracted from OLI2 images. Principal component analyses, directional filters (ENVI 5.3 software) and the Line tool (Geomatica PCI) were used to generate the lineaments. Structural information was then extracted using Palsar radar images. Directional filters and the Line tool were used to produce the lineaments of the area. Directional rosettes were produced using Rockwork software. One thousand five hundred and five (1505) lineaments extracted from Palsar images, the longest of which has a length of 10,514 m with a total length of lineaments of 371,938.05 while eight hundred and thirty-five (835) lineaments are extracted from Landsat images, with a maximum lineament length of 20,970 m and a total length of 583,615.26 m. The major directions of the lineaments are N150, N00, N30 and N165. These major directions coincide with the major directions of the old works in the study area. The validation of the results obtained was carried out using geophysical data from the area and these data confirm the effectiveness of the results.