New lithostratigraphic data have been collected from stratigraphic sections in Quaternary marine terraces located along the northern Atlantic and southern Gibraltar Strait coasts (Morocco). The sections usually start with conglomeratic lenses and large scale cross-stratification mainly followed by parallel bedding and/or fairly planar cross-bedding, dipping shoreward and seaward. These sections are usually topped by coarse- to very coarse-grained lithofacies, formed by discontinuous organized conglomerates associated with gravelly thick calcarenite strata with sharp-and flat-topped beds and medium to large scale cross-bedding. All these deposits reflect a shoreface-foreshore prograding shallow coastal palaeoenvironment within a passive margin. Petrographic analyses of detrital modes of the arenites, show that these rocks are litharenites. Biocalcarenites have been found only at the Diki-Ksar-Sghir section. The mineralogical composition of the litharenites is mainly characterized by (i) abundance of quartz (ii) a mainly extrabasinal carbonatoclastic fraction and (iii) a very scarce detrital fraction derived from epimetamorphic and metasedimentary source rocks. The provenance of the arenites of the Quaternary marine terraces is mainly from Middle-Upper Miocene and Pliocene terrigenous successions unconformably resting on various formations of the Neogene external accretionary prism, built by the stacking of Flysch and External Domain nappes. A minor component of grains derived from the Flysch Basin and External Domains, rather than the metasedimentary and epimetamorphic units of the Internal Domain. The deposition of these Quaternary marine terraces may also have been influenced by transverse, shallow, coastal drift currents, parallel to the coast of the Gibraltar Strait, thus explaining the local occurrence of biocalcarenites within some of the analyzed terraces.

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