Late Hercynian tectonic evolution of the Jebilet Massif (Western Meseta, Morocco) based on tectono-sedimentary analyses of related Permian continental deposits

The Jebilet Massif (Western Meseta, Morocco) consists of Hercynian polyphase deformed basement rocks that are, locally, unconformably overlain by a thick series of Permian siliciclastic sediments. New tectonic and tectono-sedimentary analyses offer the opportunity to propose a refined chronology of late Hercynian events of the study area and to specify the sedimentary environment and geodynamic context of related Permian deposits. In addition to the primary Hercynian structuring, three tectonic episodes are distinguished. (1) A compressive episode of Late Hercynian pre-Permian deposits is expressed by kink bands and chevron folds associated with irregular spaced cleavage. The orientation of the kink bands, their geometry and concentration along the regional faults are in favor of a compression episode in NNE-SSW direction. This deformation is ended by the Permian deposits and also marked by reworked pre-Permian deposits with kink-bands in the basal conglomerates of these deposits. (2) The early Permian tectonic episode is responsible for the opening of N-S striking intramontane basins (Koudiat El Hamra-Haiane, KH-H, and Oulad Maachou, OM) due to E-W extension. These basins are formed as submeridian graben and hemi-graben, delimited by normal faults that separate Permian red-beds from the surrounding Paleozoic basement. The sedimentary basin fillings are mainly represented by alluvial deposits with a late early Permian (Artinskian) to middle Permian (Capitanian) ichnofauna. (3) A post-Permian compressive episode, dated to the upper Triassic-pre-Kimmeridgian, is indicated by folded Permian deposits of KH-H and OM (fold axes striking N0°–N20°), as well as reverse faults representing reactivated submeridian normal faults.