Influence of Mesozoic distension on the triggering of halokinesis in the Prerifan ridges (Morocco, southern Rif): contribution of seismic and well data

The seismic analysis has shown that the area of the Prerifan ridges is marked by the superposition of three major geological events: the Triassic-Liassic extension, salt tectonics and Miocene-Pliocene compression. These events have created the fold-faulted structures which show a saliferous heart and which are located at the top of the normal faults. This study based on the subsurface data shows that the area was marked by a very active phase of salt tectonics prior to the Miocene-Pliocene compression. A detailed analysis of the sedimentary markers, tectonic markers and halokinetic markers of the post-rift series shows that the halokinetic movements were triggered by the reactivation of normal faults and were increased with sedimentation and with the Miocene-Pliocene compression. The analysis showed that the halokinetic movements were not synchronous for all salt structures identified in the area; the first ones were recorded prior to the Domerian. This research shows also that most of the salt diapirs are pre-orogenic, and possibly had a prominent role in determining the location of folds during the Alpin orogeny.