A paleomagnetic and magnetic fabric study is performed in Upper Jurassic gabbros of the central High Atlas (Morocco). These gabbros were emplaced in the core of preexisting structures developed during the extensional stage and linked to basement faults. These structures were reactivated as anticlines during the Cenozoic compressional inversion. Gabbros from 19 out of the 33 sampled sites show a stable characteristic magnetization, carried by magnetite, which has been interpreted as a primary component. This component shows an important dispersion due to postemplacement tectonic movements. The absence of paleoposition markers in these igneous rocks precludes direct restorations. A novel approach analyzing the orientation of the primary magnetization is used here to restore the magmatic bodies and to understand the deformational history recorded by these rocks. Paleomagnetic vectors are distributed along small circles with horizontal axes, indicating horizontal axis rotations of the gabbro bodies. These rotations are higher when the ratio between shales and gabbros in the core of the anticlines increases. Due to the uncertainties inherent to this work (the igneous bodies recording strong rotations), interpretations must be qualitative. The magnetic fabric is carried by ferromagnetic (s.s.) minerals mimicking the magmatic fabric. Anisotropy of magnetic susceptibility (AMS) axes, using the rotation routine inferred from paleomagnetic results, result in more tightly clustered magnetic lineations, which also become horizontal and are considered in terms of magma flow trend during its emplacement: NW‐SE (parallel to the general extensional direction) in the western sector and NE‐SW (parallel to the main faults) in the easternmost structures.

In this paper, we present the first palaeomagnetic data (51 sites) for Mesozoic (Lower–Middle Jurassic) sediments of the Moroccan Central High Atlas and address the study of a widespread remagnetization. The remagnetization is characterized by a very stable component with systematic normal polarity, carried by magnetite. The relationship between the magnetic properties and location within the basin suggests that the acquisition of the remagnetization is controlled by basin geometry. Fold-tests indicate that the overprint acquisition is syn-folding in some structures but clearly predates the Tertiary compressional stage. Using the small circle intersection method we have calculated the remagnetization direction ( D = 336.4°, I = 29.2°). Comparison with the global apparent polar wander path indicates that the remagnetization was acquired during the Late Cretaceous (probably Cenomanian). Considering both the basinal confinement of remagnetization and the connection with other remagnetization events in the western Tethys, we propose a scenario explaining widespread remagnetizations in the region, concerning both basin-scale conditions mainly related to sediment thickness and a regional-scale thermal event acting as catalyst of remagnetizations in those sedimentary basins that satisfy the basin-scale conditions.