The Westernmost Tethyan Margins in the Rif Belt (Morocco), A Review

The Rif belt is the westernmost segment of the Maghrebides and the southern branch of the Gibraltar Arc connecting North Africa to Iberia. The Rif belt formed coevally with the Betic Cordilleras (northern branch of the Arc) during the Cenozoic due to the Africa-Eurasia convergence associated with the subduction of the westernmost Tethys lithosphere of the Ligurian-Maghrebian basin. In this work, we describe the remnants of the margins of the latter basin as exposed in the Rif belt. The External Zones of the belt expose remnants of the Jurassic southern Ocean-Continent Transition (OCT) of the Maghrebian Tethys and a Triassic volcanic-rich segment of the NW African passive margin. These consist, respectively, of serpentinites and gabbros slivers included in the accretionary prism derived from the inversion of the African passive margin. The northern margin of the Maghrebian Ocean is classically represented by the Dorsale Calcaire and Predorsalian Triassic-Paleogene units at the external border of the Internal Zones (Alboran Domain). The latter mainly consists of two complexes of basement nappes, from top to bottom, the Ghomarides (Malaguides in Spain) and the Sebtides (Alpujarrides in Spain). The Dorsale sedimentary units are transitional between the Ghomarides-Malaguides coeval sequences and the Maghrebian Flyschs deposits. They likely detached from the Sebtides-Alpujarrides thinned crust domain. Marbles of probable Triassic age overlie the granulites (kinzigites) envelope of the Beni Bousera peridotites included in the Lower Sebtides units. Thus, the mantle of the Sebtides-Alpujarrides domain would have been exhumed close to the surface as early as the Triassic during the incipient formation of a Jurassic magma-poor margin bordering the Maghrebian Tethys to the north.