Applying Remotely Sensed Imagery to Extract Geological Lineaments South Rifian Ridges, Morocco

The South Rifain ridges are an example of tectonic-sedimentation interaction in the Mio-Plio-Quaternary foreland basins at the front of the Rif chain. is an elongated mountain zone-oriented E-W and N-S, forming the most frontal part of the Rif belt. The morphotectonic study carried out in this area is based on Landsat-8 OLI image processing techniques to determine the contribution of these images to structural mapping. The results obtained reveal a predominant E-W orientation, which is widely present throughout the study area. This is followed by a second N-S direction, a third NW-SE direction, and a fourth NE-SW direction. The NW-SE lineaments are also mapped in kilometres. Their equivalent on the ground shows a sinister movement but does not show a significant horizontal displacement of more than a few metres. Together with the NE-SW faults, these faults form a conjugate system of dextral and sinistral faults, compatible with a palaeostress field where the maximum shortening stress is submeridian

Crustal anatexis in the Aouli-Mibladen granitic complex : A window into the middle crust below the Moroccan Eastern Variscan Meseta

The Moroccan Variscan belt comprises numerous granitoid bodies, which have been isotopically studied, but still lack a detailed petrogenetic model. The Variscan Aouli-Mibladen granitic complex in the Moroccan Eastern Meseta provides an excellent opportunity for studying the petrogenesis and the relationship with adjacent Cambro-Ordovician metasediments. This region exposes mainly M-to I-type metaluminous mafic to granitic bodies as well as migmatites and peraluminous S-type anatectic granites. An exceptional xenoliths and garnets cumulate deposit covers an area of ∼2 km 2 located NE of the complex. The S-type suite includes cordierite bearing microgranite dykes and two small two-mica leucogranitic stocks, crosscutting the eastern metamorphic aureole of the complex. Petrological analysis shows that biotite dehydration melting reactions produced anatectic melt and peritectic cordierite and garnet. Garnet shows complex zoning profiles, with typical prograde growth zoning in the core, and resorption and reprecipitation rims. Peritectic cordierite (X Fe = 0.37) is associated with restitic biotite (X Fe = 0.65), whereas abundant cotectic cordierite (X Fe = 0.65) belongs to the granites paragenesis (Bt + Kfs + Pl + Crd + Qtz). Garnet crystals are also frequently mantled by a retrograde cordierite type. Thermodynamic modelling shows that biotite dehydration melting took place under granulitic facies conditions (830–870 °C and 6 kbar), producing a significant amount of peraluminous melts. Their ascent and emplacement led to the S-type suite of the Aouli-Mibladen complex, including the local xenolith-cumulate deposit. We envisage a petrogenetic model during the Variscan orogeny, in which mantle derived mafic magmas stagnated in large reservoirs at 18–20 km depth, causing isobaric heating and partial melting of the surrounding metapelitic protolith. Differentiated M-I-type and S-type magmas were emplaced at higher levels concomitantly, with limited mixing and mingling during their final crystallization, at a depth of 9–10 km leading to contact metamorphism (600 °C, 3 kbar). These findings open a window into the hitherto unknown Moroccan Variscan mid-crust and permit to discuss the nature and age of the underlying basement terranes