Structural analysis of the South Atlas Fault System (Morocco): Inferences about the evolution of an intraplate chain in the frame of the Atlantic Ocean opening

The High Atlas chain is an intracontinental fold and thrust belt located in Morocco, NW Africa. We provide a detailed geological-structural analysis of two areas (around Toundoute, north of the Ouarzazate basin, and Jebel Timidrout West of Errachidia) at the southern leading edge of the Central High Atlas, along the South Atlas Fault System. The main structures in these areas are thrusts and related folds, mainly E-W to ENE-WSW striking and Sverging, and locally NW-SE striking and SW-verging. Kinematic indicators collected along the main structures are coherent with the main trend of structures revealing compression directions mainly spanning from NE-SW to N-S through time. Based on both cross-cutting and superposition criteria and on the age of syn-deformational deposits, we defined main evolutionary stages that characterized the compressive regime related to the Central High Atlas evolution: Middle Jurassic, Late Cretaceous and Pliocene-Quaternary. The oldest stages roughly correspond to stages of evolution of the Central and Southern Atlantic Ocean, and we propose that the deformations detected along the southern margin of the Central High Atlas are due to intraplate stress propagation.