Publications (7)2.43 Total impact
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Article: The South-Western Branch of the Variscan Belt: Evidence from Morocco
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ABSTRACT: This work is based on the compilation and re-evaluation of the most significant data, either personal or from the literature, concerning the Moroccan Variscides. The latter constitute the only, moderately disturbed or even undisturbed part of the South-Western Branch of the Variscan Belt, facing directly NW Gondwana. They include two orogenic segments, namely the northern Mauritanides and the Meseta Domain exposed in the Saharan and Atlas–Meseta regions respectively, and a foreland belt cropping out essentially in the Anti-Atlas. The eastward thrust units of Saharan Morocco (Oulad Dlim) mostly originate from the West African Craton (WAC) border in an area of thin Palaeozoic sedimentation. Thin-skinned fold–thrust foreland arcs develop progressively northward (Zemmour) at the expense of the increasingly thick Palaeozoic series, whereas thick-skinned deformation characterizes the inverted proximal paleomargin in the Anti-Atlas Domain. As suggested by the Meseta and Anti-Atlas stratigraphic similarities, the Meseta Domain corresponds to a collage of moderately displaced, thinned crustal blocks from the distal Gondwana paleomargin. Variscan deformation is dominated by NW-verging thrusts, and metamorphism developed in the thickened tectonic prism in relation with crustal anatexis at depth. The Meseta–Anti-Atlas boundary is a major, ENE-trending transpressional dextral fault referred to as the South Meseta Fault (SMF). Discussing the correlations between the Variscan segments of Morocco and SW Iberia allows us to suggest that a latitudinal transform zone similar to the SMF separated these segments during the Late Palaeozoic. Subduction of the Rheic Ocean crust would have been directed SE-ward along both the Iberian and Moroccan Meseta, and NW-ward south of the SMF, i.e. along the WAC.Tectonophysics 07/2010; · 2.43 Impact Factor -
Chapter: Conclusion: Continental Evolution in Western Maghreb
09/2008: pages 395-404; -
Chapter: The Variscan Belt
01/2008: pages 65-132; , ISBN: 10.1007/978-3-540-77076-3 -
Chapter: The Pan-African Belt
01/2008: pages 33-64; , ISBN: Doi: 10.1007/978-3-540-77076-3 -
Chapter: The Cretaceous-Tertiary Plateaus
01/1970: pages 331-358; -
Article: Apatite fission-track analyses on basement granites from south-western Meseta, Morocco: Paleogeographic implications and interpretation of AFT age discrepancies
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ABSTRACT: This work is based on apatite fission-track analysis of samples (mostly granites) from the basement of the Cretaceous–Tertiary Phosphate and Ganntour Plateaus, exposed in the Jebilet and Rehamna massifs (Western Meseta, Morocco). This basement belongs to the Carboniferous–Early Permian Variscan Belt, and the earlier marine onlap is Late Triassic in age. However, the AFT ages are post-Triassic and different in the Jebilet (186–203 Ma) and Rehamna (148–153 Ma). Track length modelling support the occurrence of moderate heating events during the Jurassic and the Eocene, respectively, with cooling during the Permian and Cretaceous intervals. These results are partly accounted for by considering a moderate subsidence during the Late Triassic–Liassic, which is a noticeable change in the regional paleogeographic concept of “West Moroccan Arch”. However, the discrepancies between the AFT results from the studied massifs make necessary to explore further explanation. We interpret the observed discrepancies by the difference in age and depth of crystallization of the sampled granites in the Variscan Orogen, i.e. 330 Ma, 5–6 km in the Jebilet versus ~ 300 Ma, 8–10 km in the Rehamna. The importance of the Late Jurassic–Early Cretaceous uplift and erosion of the entire Meseta and that of its Late Eocene burial are emphasized.Tectonophysics. -
Article: The South-Western Branch of the Variscan Belt: Evidence from Morocco
[show abstract] [hide abstract]
ABSTRACT: This work is based on the compilation and re-evaluation of the most significant data, either personal or from the literature, concerning the Moroccan Variscides. The latter constitute the only, moderately disturbed or even undisturbed part of the South-Western Branch of the Variscan Belt, facing directly NW Gondwana. They include two orogenic segments, namely the northern Mauritanides and the Meseta Domain exposed in the Saharan and Atlas–Meseta regions respectively, and a foreland belt cropping out essentially in the Anti-Atlas. The eastward thrust units of Saharan Morocco (Oulad Dlim) mostly originate from the West African Craton (WAC) border in an area of thin Palaeozoic sedimentation. Thin-skinned fold–thrust foreland arcs develop progressively northward (Zemmour) at the expense of the increasingly thick Palaeozoic series, whereas thick-skinned deformation characterizes the inverted proximal paleomargin in the Anti-Atlas Domain. As suggested by the Meseta and Anti-Atlas stratigraphic similarities, the Meseta Domain corresponds to a collage of moderately displaced, thinned crustal blocks from the distal Gondwana paleomargin. Variscan deformation is dominated by NW-verging thrusts, and metamorphism developed in the thickened tectonic prism in relation with crustal anatexis at depth. The Meseta–Anti-Atlas boundary is a major, ENE-trending transpressional dextral fault referred to as the South Meseta Fault (SMF). Discussing the correlations between the Variscan segments of Morocco and SW Iberia allows us to suggest that a latitudinal transform zone similar to the SMF separated these segments during the Late Palaeozoic. Subduction of the Rheic Ocean crust would have been directed SE-ward along both the Iberian and Moroccan Meseta, and NW-ward south of the SMF, i.e. along the WAC.Tectonophysics.
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Institutions
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1970–2008
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Université Paris-Sud 11
Paris, Ile-de-France, France
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