Late Palaeozoic sediments in central Morocco and the High Atlas Mountains document the development of this area during the formation of the Mauretanide part of the Hercynian orogeny. Continental basins formed during the Stephanian and Permian. Although scattered in time, they provide valuable biogeographical and climatic information for the Mauretanides as a link between the Variscides in the east, the Appalachians in the west and the Karoo in the south. New blattid insects in the Souss Basin enable correlation to Early Stephanian B. Furthermore, we document the oldest African tetrapod tracks (Batrachichnus, Dromopus). Litho- and biofacies indicate seasonally wet and dry phases. Wet red beds of the Khenifra Basin have produced tetrapod bones and the tracks Limnopus, Batrachichnus and Dromopus. Macrofloras give a transitional Autunian/Saxonian age. This fits well into the Artinskian wet phase. Similar facies pattern in the Tiddas Basin are correlated by tetrapod tracks as transitional Artinskian to Kungurian. Advanced tetrapod tracks of Synaptichnium and Rhynchosauroides were discovered in the Ikakern Formation of the Argana Basin, dated by pareiasaur remains as Wuchiapingian. Red beds of similar type are known in Europe, for example, from the Late Permian of the Lodève Basin. They originated during the Wuchiapingian wet phase.

The Gourougou volcanic massif (northeastern Morocco) is actively prospected for bentonite deposits. Five bentonites originating from different environments were selected for the present study: hydrothermal alteration of obsidian perlite glass inside the volcanoes themselves (Providencia and Tribia deposits); alteration of pyroclastic flows in a marine shallow water to lagoonal lacustrine environment (Ibourhardayn deposit); ash falls in marine or lacustrine systems (Moulay Rachid and Melg el Ouidan (formerly Camp Berteau) deposits). All of these bentonites were probably formed from volcanic glass originating from a rhyolitic magma at different stages of differentiation as shown by slight variations of REE and incompatible element abundances. The crystal-chemical characteristics of the smectite vary according to alteration conditions: beidellite predominates in hydrothermal systems, whereas montmorillonite predominates in lagoonal and lacustrine environments, and mixed-layer beidellite-montmorillonite in the sea-water-altered pyroclastic flows. All these dioctahedral smectites exhibit a heterogeneous distribution of charge as shown by the presence of partially expandable (1 EG) or non- expandable (0 EG) layers in the K-saturation state. The proportion of the collapsed or partially expandable layers is not related to the average layer charge or to the cation exchange capacity. This militates for an overall heterogeneous charge distribution. Compared to other natural or experimental alteration systems of similar rhyolitic glass, the formation of beidellite or montmorillonite appears to be controlled by the amounts of Mg in the system.

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HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Mise en place syntectonique des minéralisations cuprifères du gîte d'Ifri (district du Haut Seksaoua, Haut Atlas occidental, Maroc)-Syntectonic emplacement of the Ifri copper mineralization (High Seksaoua, western High Atlas, Morocco)

El objeto de este estudio es la gestión del riesgo de inundaciones mediante el uso de cartografía de riesgo de inundaciones por ríos caudalosos. La cartografía se obtiene mediante aplicaciones de simulación modernas, como el modelo hidráulico (HEC- RAS) y la aplicación informática de Sistemas de Información Geográfica (SIG) ArcGis. El estudio se aplica en los alrededores de Oued El Harrach (norte de Argelia), objeto de varias inundaciones que han generado pérdidas humanas y materiales considerables. Estas pérdidas son consecuencia del uso de zonas inundables como zonas residenciales, pudiendo evitarse en el futuro en la zona de Oued El Harrach con la ayuda de cartografía del alcance espacial de los riesgos de inundación. Por ello la importancia de la cartografía desarrollada en este estudio como herramienta esencial para los gestores en prevención y protección en materia de riesgos de inundaciones.