Search

The Southern Variscan Front in the Tinerhir area involves Palaeozoic allochthonous units (Ouaklim and Tilouine units) thrust onto the northern edge of the West African Craton during late Carboniferous time. Illite crystallinity data highlight an anchizonal grade for the Ouaklim Unit, and a diagenesis-anchizone transition for the Tilouine Unit during deformation phase D1. The tectonic stack is crosscut by major dextral reverse faults bounding E–W trending domains of dominant shortening deformation (central domain) and strike-slip deformation (northern and southern domains), later segmented by a network of post-Variscan faults. This complex deformation pattern is the result of kinematic partitioning of dextral transpression along the Southern Variscan Front, coeval with the Neovariscan (300–290 Ma) oblique convergence observed at the scale of the whole Moroccan Variscides. Partitioning of dextral transpression described in the Tinerhir area is consistent with dextral wrench faulting along the Tizi n’ Test Fault, and with Appalachian-style south-directed thrusting in the Tinerhir and Bechar-Bou Arfa areas. [ABSTRACT FROM AUTHOR]

The High Atlas belt of Morocco is a doubly vergent intracontinental belt formed during Cenozoic convergence between the African and Eurasian plates. This belt is characterized by the simultaneous occurrence of high topographic elevation, minor crustal thickening and weak tectonic shortening, which are commonly explained by models of inversion tectonics and mantle upwelling. This paper aims to test the consistence of this type of model, presenting the results of a multi-scale tectonic study, including mapping of major faults and fault-slip data inversion, from key areas homogeneously distributed through the entire High Atlas. Our data highlight kinematic components parallel to the orogen trend, supporting a transpressional structuring. Integration between new tectonic data and available geophysical and thermochronologic constraints has allowed to extend to depth the main faults detected at the surface, resulting in the overall geometry of a positive flower structure. This scenario is the result of a long history of transpressional and transtensional reactivations of major lithospheric faults since the break-up of Pangea. Lithospheric-scale faults isolate independently-behaving lithospheric blocks characterized by different exhumation rates. In this framework, the compressive component of the transpressional geodynamic regime can produce the high topographic elevation of the High Atlas belt without crustal thickening. Image 1 [ABSTRACT FROM AUTHOR]