The contribution of landsat 8 oli multispectral data to the lithological mapping of the Ait Ourir basin (Western High Atlas, Morocco)

Abstract

The present work consists in identifying the geological facies and defining the dominant orientation of the lineaments in order to improve the knowledge on the local geodynamics in the Northern Sub-Atlasic zone of the Marrakesh High Atlas, the Ait Ourir basin region, The latter is characterized by a post-Hercynian Mesozoic cover folded into broad synclines with flat and subhorizontal bottom, separated by ejective and sharp anticlines. For this purpose, multispectral data from Landsat 8 operational land imager (OLI) have been applied in a platform of ArcGIS software and through the treatments offered by this software, namely, the principal component analysis (PCA), the band ratios (BR) and the transformation of the minimum noise fraction (MNF), a better lithological discrimination and description was brought to the set of geological formations that form the studied basins. In parallel, the results obtained by the method of classification by Support Vector Machine (SVM), which is based on the joint use of geomorphic features, textures and multispectral data from Landsat 8 satellite, showed an excellent correlation. With the simplified geological map of the northern slope of the High Atlas of Marrakesh (1/10000) and field data from the study area. The result shows an overall accuracy of classification of Landsat8 OLI data by SVM which is 96.64% and the Kappa coefficient which is 0.98 and a positive correlation is shown between lineament structures and dominant orientations of the extracted lineaments. The highest densities obtained are N-S, NE-SW and NNE-SSW oriented with the predominance of the first direction.