The Jbel Rhals deposit, located in the Oriental High Atlas of Morocco, hosts a polymetallic Fe-Mn-Cu ore. Large metric veins of goethite and pyrolusite cut through Paleozoic schists that are overlaid by Permian-Triassic basalts and Triassic conglomerates. The genesis of this deposit is clearly polyphased, resulting from supergene processes superimposed over hydrothermal phases. The flow of Permian-Triassic basalts probably generated the circulation of hydrothermal fluids through the sedimentary series, the alteration of basalts and schists, and the formation of hydrothermal primary ore composed of carbonates (siderite) and Cu-Fe sulfides. Several episodes of uplift triggered the exhumation of ores and host rocks, generating their weathering and the precipitation of a supergene ore assemblage (goethite, pyrolusite, malachite and calcite). In the Paleozoic basement, Fe-Mn oxihydroxides are mostly observed as rhombohedral crystals that correspond to the pseudomorphose of a primary mineral thought to be siderite; goethite precipitated first, rapidly followed by pyrolusite and other Mn oxides. Malachite formed later, with calcite, in fine millimetric veins cutting through host-rock schists, conglomerates and Fe-Mn ores.

En los últimos años, la teledetección ha ocupado un lugar destacado en los programas de exploración minera dada su utilidad para identificar minerales de alteración, como la arcilla y los hidróxidos. Estos minerales son guías significativas para encontrar depósitos minerales que albergan concentraciones valiosas de metales base. Este trabajo se centra en las mineralizaciones de Fe-Mn-Pb dentro del área de Jbel Skindis consideradas como un zona de estudio para ilustrar la aplicación de imágenes de teledetección y de un sistema SIG para delinear zonas de interés para la exploración minera y extraer información sobre los factores que controlan las concentraciones de metales utilizando tratamiento de datos satélites e integración de imágenes. De acuerdo con las observaciones de campo y los datos DRX las principales anomalías de alteración deducidas del tratamiento de datos satélite se caracterizan por óxidos e hidróxidos. En base a estos minerales, se realizó un mapeo utilizando los datos de Aster L1T y Landsat 8 OLI: la relación 5/4 resalta las zonas de Gossans mientras la combinación RGB (4/6, 2/1, 3/2) señala las áreas alteradas. El mapa de lineamientos extraído de las imágenes de Sentinel 2A y Landsat permitió reconstituir la red de megafracturas que afectó a la región. El acoplamiento entre un análisis multi-criterio de los datos derivados de satélites y los datos geológicos disponibles, permitió delinear zonas de interés para la exploración minera en el área de estudio. Estas zonas corresponden a áreas altamente fracturadas en las cuales se desarrollan gossans y alteración rica en Fe. Este enfoque junto con un control a través de un estudio de campo, se aplicó con éxito en el área de Jbel Skindis para delinear rápidamente los afloramientos de mineralizaciones oxidadas. Esto proporciona un modelo de teledetección para futuros esfuerzos de prospección de depósitos minerales similares tanto en la provincia oriental del Alto Atlas como en otras áreas similares.

The Achemmach region is located 40 km to the SW from Meknes city and 6 km to the NE frm the Hammam mine. It is part of the Paleozoic massif of Central Morocco. The studied area is formed by two Paleozoic rock-types: (i) a meta-sedimentary sequence composed of Middle Visean limestone and shale-sandstone withflyschoid of Upper Visean-Namurian age, and (ii) a magmatic rock series represented by volcanic rocks (pillow-lavas), hypovolcanic rocks (dolerites) and olivine-bearing gabbros.Based on the emplacement model, structural framework, relative chronology and petrogeochemistry of the magmatic rocks, for the first time in this area we distinguish: (i) dm to m-sized greenish pillow-lavas, with sharp borders and radius fractures underlined by fine greenish pelitic sedimentary intercalations, indicating recurrent volcanic activity in short episodes. Plagioclases and pyroxenes (augite) microlites, and more rarely phenocrystals, are recognizable in a glassy matrix devoid of recognizable olivine. (ii) Deformed, metamorphosed and altered dolerites dikes intrude the Middle to Upper Visean shale-sandstone formations. They have an overall NE-SW direction with a NW dip. They are composed of sericitized plagioclases, associated with partially to totally amphibolitized pyroxenes, tourmaline with differentdegrees of chlorite substitution, rutile and opaque minerals, in a microliticmesostasis and (iii) olivine-bearing gabbros, outcropping in variable dimensions (a few meters to 20 m). The olivine-bearing gabbros have a granular texture and are mainly made of plagioclases, pyroxenes, olivine, titanite, rutile, apatite and opaque minerals. All igneous minerals have undergone different degrees of replacement by secondary minerals; plagioclases are sericitized and albitized, pyroxenes are amphibolitized and epidotized and olivine is serpentinized and chloritized. Thepetro-geochemical study of these magmatic bodies demonstrates that pillow-lavas basalts and olivine-bearing gabbros have an alkaline affinity, while dolerites are thought to have a transitional alkaline affinity (alkaline-tholeiitic). Therefore, these formations would have been set up in anorogenic intra-continental geodynamic context, corresponding to a basin magmatism in the little evolved opening.

The abundance of the NE-SW direction veins mineralized in barite, copper, lead and zinc in the Tadaout-Tizi n'Rsas (TTR) anticline make this area one of the principal vein fields in Tafilalet (easternmost border of the Eastern Anti-Atlas). Reactivation of faults and alternation of competent (thicks Ordovician series, Silurian limestone and Devonian limestone) and incompetent levels (Silurian shales and Devonian marls) have an important role in the deformation of the TTR anticline during the NE-SW Variscan shortening. Our work based on lineaments extraction using a Landsat 8 OLI combined with some geological cross sections, shows a N130° major fold corresponding to TTR anticline. This big fold shows internal N130°, N95° and N20° minor folds. This structure indicates that the TTR area was formed in the hinge between the Anti-Atlas and the Ougarta belts. A number of these folds are the consequence of the underlying Precambrian faults reactivation and alternation of competent and incompetent levels. Brittle tectonics is dominated by NE-SW normal faults which result from the NE-SW shortening consequence of the Gondwana and Eurasia continents collision. Consequently, the mineralization of TTR is necessarily related to late or post-Variscan orogeny.