干旱区生态环境知识资源中心

The Messak is a central Saharan massif cut into Cretaceous sandstone and delimited to the north and the west by a high scarp. It is a relict of a peneplain, dissected by dendritic wadis, and has originated since the late Tertiary under a rich water supply. Geomorphological mapping of the area was carried out by means of field survey and satellite imagery analysis. Due to the almost complete absence of vegetation (related to arid environmental conditions), the analysis of multispectral data permitted the identification of the main geomorphological units, while a band ratio allowed characterization of the properties of the exposed land surface. The main physiographic units correspond to residual surfaces (hamada and serir, resulting from etchplanation and linear erosion), solutional depressions, slope deposits, and a composite escarpment. Most of the geomorphological features are fossil, originating during warm and rainy phases dated to the Tertiary, the Pleistocene interglacials, and the Early Holocene.