Resumen de Les granitoides tardi-panafricains de l'Anti-Atlas sud-occidental (Maroc): Evolution d'un type magnésien à un type ferrifére. Exemple de la boutonniere d'Ifni
A. Mortaji, D. Gasquet, M. Ikenne, E.H. Beraaouz, M. Lahmam
The study of the neoproterozoic granitoids in the Ifni Inlier and those of the other inliers in south-westerner Anti-Atlas shows that this magmatism evolves from magnesian to ferroan type. In the Ifni inlier, these granitoids outcrop within the sedimentary and volcanogenic formations of the Ouarzazate Super- Group SGO (615 to 540 My). They belong to two distinct magmatic episodes (i) an early one composed of magnesian granitoids with alkali-calcic and metaluminous to slightly aluminous character (quartz bearing diorite, granodiorite and monzogranite) intrusive in the lower formations of the SGO, and (ii) a late episode associated to the summit of the SGO volcanites, which includes granites and sub-volcanic syenogranites of iron-bearing type and alkali-calcic to alkaline affinity. These magmatisms resulting from the partial melting of mixed material mark the end of the last Panafrican episode and would be set up in a transition from orogenic to anorogenic settings which announce the Paleozoic cycle. They would be contemporary to posterior with the exhumation of the extensive metamorphic domes of the Western Anti-Atlas.
