Papers by mohammed kahoui
… 2010, held 2-7 May …, 2010
Journal of African Earth Sciences, 2012
Pyrope garnet grains found in Cretaceous and Quaternary alluvial sediments in the El Kseibat area... more Pyrope garnet grains found in Cretaceous and Quaternary alluvial sediments in the El Kseibat area (Algeria) suggest the presence of kimberlites along the NE margin of the West African Craton. The garnets have been studied using major-and trace-element chemistry ...
Tectonophysics, 2014
ABSTRACT The Eburnean A-type granitic Djebel Drissa ring complex is part of the 2.08 Ga Aftout ma... more ABSTRACT The Eburnean A-type granitic Djebel Drissa ring complex is part of the 2.08 Ga Aftout magmatic suites that intruded the 2.22-2.09 Ga-old Paleoproterozoic granitoids in the Eglab shield. This post-collisional pluton is composed of unfoliated granitoids disposed in near-concentric zones. The zoning feature is interpreted as intrusions of continuous magmatic pulses, leading to its in situ growing. New field observations and new geophysical data are presented in order to determine the structural context of Djebel Drissa complex emplacement. The magma internal structures were obtained by mapping the magnetic structures (foliation and lineation) from an Anisotropy of Magnetic Susceptibility (AMS) study. Modeling from together gravimetric and aeromagnetic data yielded its geometry in depth. The combined use of data of these different approaches provides a new and enriched image of the Drissa complex and of its evolution. Indeed, these data point out that the regional deformation controlled the emplacement of this complex. The sub-circular shape of the granitic body and AMS strain pattern are consistent with a transtensional tectonic setting along the NW-SE major Chenachane shear-zone and with an emplacement also controlled by an associated WNW- ESE extension fault. From all these data, a reliable model was inferred for the evolution of this ring complex, which emplacement marked the end of the main Proterozoic history of the Eglab shield.
Geological Society, London, Special Publications, 2008
The Eglab shield is the easternmost part of the Reguibat rise, which belongs to the West African ... more The Eglab shield is the easternmost part of the Reguibat rise, which belongs to the West African craton (WAC). It corresponds to the amalgamation of the Yetti and Eglab Palaeoproterozoic domains. These domains are separated by a mega-shear zone called the ‘Yetti–Eglab Junction’ where fieldwork has led to the discovery of kimberlite indicator minerals but no diamond. In the southwestern part of this zone, an outcrop of Archaean basement and a komatiitic–picritic dyke had been recognized. Within the Eglab shield, deep-seated lithospheric faults control emplacement of alkaline complexes, and of small circular structures made up of mafic, ultramafic and silica-undersaturated rocks. These structural zones are characterized by widespread development of dyke swarms and repeated reactivations of earlier Eburnean trends from the Neoproterozoic to Mesozoic. Accordingly, they are sites of high magmatic permeability and crustal weakness. In this study, we summarize all known earlier and newly o...
The Gara Adjemamaye peralkaline granite outcrops in the Egere-Aleksod terrane (central Hoggar). T... more The Gara Adjemamaye peralkaline granite outcrops in the Egere-Aleksod terrane (central Hoggar). The main facies is a grey to cream heterogranular rock composed of quartz, mesoperthite, sodi-calcic amphibole, sodic pyroxene, annitic biotite, opaques, Fe-Ti ...
The Djebel Drissa ring complex (16×12km) belongs to the Aftout granitoids in the Eglab Shield, th... more The Djebel Drissa ring complex (16×12km) belongs to the Aftout granitoids in the Eglab Shield, the easternmost part of the Reguibat Rise (West African Craton). It was emplaced during the Palaeoproterozoic Eburnian orogeny along a mega-shear-zone and intruded a volcanic cover of fissural origin (rhyolite, rhyodacite, andesite); it is composed of metaluminous and peralkaline granites belonging to the alkaline family.The Djebel Drissa ring complex, dated at 2081±13Ma, possesses structural, petrological, mineralogical and geochemical features similar to other alkaline–peralkaline post-collisional complexes known in the world. Partial melting of an enriched lithospheric mantle and fractional crystallization are envisaged for the genesis of these granitoids.
Precambrian Research, 2005
The Eglab massif, situated in the northern part of the West African Craton (WAC), exhibits a spec... more The Eglab massif, situated in the northern part of the West African Craton (WAC), exhibits a specific Eburnean evolution compared to that known in the southern part of the WAC. Two major orogenic stages are recognized in the Eglab massif. The first one corresponds mainly to 2.212.18 ...
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Papers by mohammed kahoui