The Oulad Ouaslam Variscan granitic pluton (Jebilets Massif, Southwestern Moroccan Meseta): A forcibly emplaced laccolithic intrusion characterized by its magnetic and magmatic fabrics

摘要

The study of the magmatic fabrics of the Oulad Ouaslam Variscan granitic pluton, based on the Anisotropy of Magnetic Susceptibility technique, allows us to propose that this 30 km long laccolith corresponds to a forcibly emplaced intrusion which proceeded from west to east into its country rock of Carboniferous metapelites. The fact that the magmatic fabrics measured in this pluton are obliquely cut, in the southwestern part, by solid-state structures (cleavage, shear bands) related to the regional main phase of deformation shows that the pluton was emplaced before this phase. Consequently, the tectonic control of this emplacement appears to have been much less important than it was suggested in the previous interpretations which considered, on the basis of the study of the solid-state fabrics, a syn-tectonic emplacement of this granite, possibly linked to a sinistral NNW-SSE shear zone. Our results contribute to the definition of a new framework for the tectonic history of this part of the Variscan chain.