Tectonic evolution of the Triassic diapirs in the southern front of the Rif belt, Northern Morocco

Abstract

Located at the front of the external Pre-Rif, northern Morocco, at the edge between the Rif cordillera and the Saiss neogen basin, Triassic diapirs constitute one of the main features of this area, occurring within the Meso-Cenozoic allochthonous formations. In order to understand their geological setting and evolution during the Meso-Cenozoic times, we carry out a geological study based on structural analysis and fracturing field investigations. The obtained results are completed by previous geophysical and seismic works. The rising salt bodies (halite, anhydrite and gypsum) in those diapirs was controlled by the two NW-SE and NE-SW system faults from the Mesozoic to the Quaternary. The contacts between the Triassic material and the Miocene sedimentary marls are discussed. Some mapped tectonic contacts, considered as thrusting faults are in fact stratigraphic limits, which are characterized by polygenic conglomerates. These arguments allow us to review the whole history of these salt walls and to discuss their current geometry.