The Geographical Framework: Geology, Geomorphology and Alteration Processes of the Rock Art Surfaces

Résumé

Oukaïmeden is located in the Toubkal National Park, in the western third of the High Atlas geological domain. The geological structure of this area presents smooth folds, supracrustal thrust faults and faults placed transversally to the mean structural directions of the mountain range. There are outcropping materials from the Palaeozoic base and the Mesozoic sedimentary cover, here consisting exclusively of clastic sedimentary rocks from the Triassic period. The largest morphological feature in Oukaïmeden is the basin, limited to the north by the Tizrag morphological slope and the rugged reliefs of the Paleozoic rocks to the south, which culminate in the Jbel Angour (3.616 m.a.s.l). The most important formations are the two slopes of Triassic sandstones: Tizrag to the north, and Tifita to the south, separated by the narrow valley of the Irini River, which drains the Oukaïmeden depression to the northeast. Over these two large elements there is a remarkable group of rock carvings. However, their location vary with regard to the geological features of their near vicinity: carvings located separating strata, inside a stratum, on fractures, on fallen rocks or inside rock shelters or small cavities. Most of the carvings present a black patina with metallic reflections. Given their antiquity, their sub-horizontal position, that most of them are in open air locations and the continued use of this territory by the local population, the carvings show a wide range of alterations, described below.