Stratigraphy and Petrography of Mafic Rocks from the Western Part of the Mesorif Sub-Domain (External Rif, Morocco)

Abstract

The Rif-Betic Cordillera is atightly arcuate, oroclinal mountain belt along the western edge of the Alpine Peri-Mediterranean Orogen, it extends for ~2000 km from the Strait of Gibraltar in the West to Calabria and the Southern Apennines in the East. It developed as a result of the convergence andcollision between the Eurasian and African plates in the Miocene. The recent discovery of a suture zone with oceanic rocks in its central and eastern parts suggests that the external zone of the Rif Belt (Mesorif and Prerif Units) may include ophioliticunits. In this paper, we shed light for the first time on petrographic and stratigraphic characteristics of the mafic rocks that appear in the western part of the Mesorif suture zone as well as the Prerif sub-domain. These latter are represented by gabbro with a sub-ophitic to ophitic texture showing simple mineralogy made up of abundant euhedral to subhedral plagioclase, subhedral to anhedralclinopyroxene crystals that can be very altered and totally replaced by chlorite epidote and opaques, and less abundant olivine. Alteration phases include chlorite epidote and tremolites.