Abstract

New petrographic and sedimentological data from the Oligocene Miocene Mauretanian flysch of the Rifian Chain (Beni Ider Flysch) and from the terrigenous deposits unconformably overlying the internal Rifian zones (Ghomaride and Sebtide Units) provide evidence of sedimentary supplies also from plutonic and high rank metamorphic sources. This provenance, in agreement with the available data from other equivalent turbidite successions of the Sicilian sector of the Maghrebian Chain, is supported by the occurrence of well rounded plutonic (leucogranodiorite - leucomonzogranite) and high rank metamorphic (augen gneisses) pebbles within some conglomerate lithofacies of the Beni Ider Flysch, never found so far. Petrography of these crystalline pebbles is very similar to that of the syn- late-Hercynian plutonic bodies and of the gneissic rocks widespread in the Calabria-Peloritani Arc and, probably, in the Kabylides. Nevertheless, in the Rifian Chain, similar crystalline rocks are absent within the higher tectonic units of the pre-Alpine Paleozoic basement (Ghomaride Units). Thus, we believe that this crystalline detritus could represent the product of dismantling of a lost continental crust segment, originally located very near to the Ghomaride Domain, when all the Betic, Rifian, Tellian and Sicilian internal domains (AlKaPeCa block, sensu Boullin et alii, 1986) were still in crustal continuity with the European plate. Erosion of this inferred source area must have occurred before of the fragmentation of the AlKaPeCa block and the consequent dispersal of different crustal fragments around the new oceanic areas (i.e. before of the Aquitanian).

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