A NEW LOOK AT THE STRUCTURAL GEOLOGY OF THE SOUTHERN SIDE OF THE CENTRAL AND EASTERN HIGH ATLAS MOUNTAINS

We give a general description of two evaporite basins discovered, one under, and the other south of the Lower Jurassic carbonate platform wh ich fringes the Atlas Gulf in the south. The larger of these basins li es in the triangle Tazzouguert, Aoufouss, Tarda. The smaller, whose ex tent is difficult to determine (it being considerably deformed and par tially covered over by the southward sliding of the Liassic carbonate platform), lies north of Tinerhir and Ifer. Marl and evaporite Middle Liassic deposits from this smaller basin form a tectonic window in the massive limestones of the Liassic carbonate platform at Tisgui (Todrh a gorges). This window clearly shows that the zone in question was aff ected by southward sliding. To the East of Tazzouguert going towards B ouanane the carbonate platform backs directly onto the African craton. In the area we studied we noticed that the Liasic platform-basin boun dary was controlled by at least two major faults (and not just one as we had thought). Between Tinerhir and >> Tunnel de la Legion <<, the T izi n'Firest Fault provided the main structural control of sedimentati on during the Lias. The open sea is situated North of this fault. East of the oued Ziz valley and 10 kilometers south of >> Tunnel de la Leg ion <<, it was the Jbel Dermchane Fault which provided the same contro l of sedimentation.