The Palaeozoic terranes that crop out north of the South Atlasic Line constitute the Variscan Belt of North Africa. Subdivision of the belt into five structural zones separated by major shear zones results from a polyphase evolution including very localised Prevariscan events (450-430 Ma), which correspond to the Caledonian cycle, and Variscan events involving three main stages: Eovariscan (370-360 Ma), Mesovariscan (330-320 Ma), and Neovariscan (300-290 Ma), followed by Tardi-Variscan events during Early Permian-Triassic times. During the Variscan evolution, the geodynamic context is transtensive-transpressive, and controls the opening and closure of Devono-Carboniferous basins. The Variscan deformations are accommodated by folding and combination of thrusting and strike-slip faulting associated with a low-grade to medium-grade metamorphic evolution, characteristic of the external zones of the orogens. The lack of oceanic crust, and thus of suture zone in the Palaeozoic series suggests that the North African Variscan Belt is an intracontinental part of the Variscan orogen, which evolved near the margin of the West African Craton. The links with the other Periatlantic Palaeozoic segments still remain a subject of discussion.
The present work aims at understanding the tectonic evolution of the Jebilet massif, Morocco, during the Late Paleozoic as constrained by structural, metamorphic, and geochronological studies. From Late Devonian to Early Carboniferous, bordering faults controlled the opening of the Jebilet intracontinental basin (D0 stage) as shown by sedimentary infill. This episode was accompanied by a magmatic activity, newly dated between 358 ± 7 Ma and 336 ± 4 Ma. The first record of the Variscan event affected the Jebilet by the Late Visean‐Namurian and is represented by allochthonous superficial nappes emplaced at shallow depth in a moderately lithified sedimentary succession. D1 also developed regional‐scale recumbent folds trending E‐W that may suggest N‐S crustal shortening not generating crustal thickening nor contributing to metamorphism. The main Variscan D2 episode consists of a progressive evolution from bulk coaxial deformation to noncoaxial dextral transpression consistent with NW‐SE horizontal shortening, resulting in a moderate thickening. This episode was accompanied by HT‐LP metamorphism and syntectonic intrusions controlled by an inherited thermal anomaly in relation with the intracontinental rifting stage (D0). Based on previous age determinations from syntectonic leucogranite and metamorphic rocks, D2 is dated between 310 and 280 Ma. The tectono‐metamorphic evolution of the Jebilet massif can be correlated with a plate‐tectonic scenario evolving from, first a Late Devonian‐Early Carboniferous basin formation during stretching of the north‐Gondwana margin and initiation of the Paleotethys Ocean, and, second, to a Late Carboniferous‐Early Permian ocean closure (Rheic or Paleotethys Oceans depending of scenarios) that resulted in the final Variscan‐Alleghanian tectonics.
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