Plio-Quaternary paleostresses in the Atlantic passive margin of the Moroccan Meseta: Influence of the Central Rif escape tectonics related to Eurasian-African plate convergence |
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| Institution: | 1. Institut Scientifique, Université Mohammed V—Agdal, Rabat, Morocco;2. Faculté des Sciences, Université Mohammed V—Agdal, Rabat, Morocco;3. Institute of Earth Sciences Jaume Almera, ICTJA-CSIC, Barcelona, Spain;4. Real Instituto y Observatorio de la Armada, San Fernando, Cádiz, Spain;5. Instituto Andaluz de Geofísica, Universidad de Granada, Granada, Spain;6. IGEO and Universidad Complutense de Madrid, Madrid, Spain;7. Departamento de Geodinámica Interna, Universidad de Oviedo, Oviedo, Spain;8. Instituto Geológico y Minero de España, Madrid, Spain;9. École Nationale des Sciences Appliquées, Université Mohammed Premier, Oujda, Morocco |
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| Abstract: | The Atlantic Moroccan Meseta margin is affected by far field recent tectonic stresses. The basement belongs to the variscan orogen and was deformed by hercynian folding and metamorphism followed by a post-Permian erosional stage, producing the flat paleorelief of the region. Tabular Mesozoic and Mio-Plio-Quaternary deposits locally cover the Meseta, which has undergone recent uplift, while north of Rabat the subsidence continues in the Gharb basin, constituting the foreland basin of the Rif Cordillera.The Plio-Quaternary sedimentary cover of the Moroccan Meseta, mainly formed by aeolian and marine terraces deposits, is affected by brittle deformations (joints and small-scale faults) that evidence that this region – considered up to date as stable – is affected by the far field stresses. Striated faults are recognized in the oldest Plio-Quaternary deposits and show strike-slip and normal kinematics, while joints affect up to the most recent sediments.Paleostress may be sorted into extensional, only affecting Rabat sector, and three main compressive groups deforming whole the region: (1) ENE–WSW to ESE–WNW compression; (2) NNW–SSE to NE–SW compression and (3) NNE–SSW compression. These stresses can be attributed mainly to the NW–SE oriented Eurasian-African plate convergence in the western Mediterranean and the escape toward the SW of the Rif Cordillera. Local paleostress deviations may be related to basement fault reactivation. These new results reveal the tectonic instability during Plio-Quaternary of the Moroccan Meseta margin in contrast to the standard passive margins, generally considered stable. |
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| Keywords: | Brittle structures Foreland deformation Recent tectonics Variscan orogen Paleostress NW Africa |
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