The use of Landsat imagery in structural studies of middle Morocco

Preliminary results of a tectonlinear study of Landsat MSS images in bands, 4, 5 and 7 covering Middle Morocco are presented. The relationships between lineaments and large-scale structural patterns are studied and compared with geological and ore deposits distribution data on the area.Middle Morocco in this article comprises parts of the Moroccan Meseta, Central and Eastern High Atlas and northeastern Anti-Atlas. Rocks of all ages, from Precambrian to Quaternary, are found, and the structural evolution of the area is due to Precambrian, Variscan and Alpine orogenies. Two main lineament sets are recognized on the satellite images. These are NE-SW and NW-SE. The NW-SE set of lineaments is prominent in older Precambrian and Paleozoic terranes, whereas the NE-SW set is observed both in the old inliers and massifs as well as in the younger mountain chains. The NE-SW lineaments therefore represent reactivated fractures that should have played an important role in the tectonics and sedimentary cycles of Middle Morocco. Other lineament trends are seen only in specific regions of the study area.Several major ore deposits follow lineament trends both in the basement and cover rocks. This is particularly true of endogenic deposits in the Anti-Atlas and in the Central Paleozoic massif.