Comment on “The Moroccan Hercynides” by Hoepffner et al. (Journal of African Earth Sciences, vol. 43, pp. 144–165)

Tectonic evolution of the Rehamna metamorphic dome (Morocco) in the context of the Alleghanian-Variscan orogeny

“…In the most popular model, a polyphase evolution of the belt is proposed starting with westward convergence in the Eo-Variscan (i.e., Upper Devonian-Tournaisian) that affected the Eastern Meseta. This event is associated with the formation of NNE striking transtensional basins in the Central Zone, followed by westward transpressional accretion of this zone to the Coastal Block during the Upper Carboniferous accompanied by N-S shortening of the Eastern Meseta [Hoepffner, 1987;Bouabdelli and Piqué, 1996;Hoepffner et al, 2005Hoepffner et al, , 2006aHoepffner et al, , 2006bMichard et al, 2010a]. This important late deformation results in the E-W structural grain of the Eastern Meseta and the NNE structural grain of the Western Meseta.…”

“…This important late deformation results in the E-W structural grain of the Eastern Meseta and the NNE structural grain of the Western Meseta. According to this scheme, the Rheic suture separating the Gondwana and Laurentia continents is hidden in the present Atlantic passive margin and continues into the African continent as the Rabat-Tiflet Fault Zone [Hoepffner et al, 2005[Hoepffner et al, , 2006bMichard et al, 2010b;Tahiri et al, 2010]. 2.…”

“…2. The alternative model proposes a continuous compression of the Variscan foreland to form the whole Moroccan Meseta in which the Rheic suture is hidden at the eastern boundary of the Eastern Meseta [Kharbouch et al, 1985, Boulin et al, 1988Roddaz et al, 2002Roddaz et al, , 2006Essaifi et al, 2014]. In both models, large-scale deformation is accommodated by strike-slip movement along the South Meseta Fault Zone and the Rabat-Tiflet Fault Zone [Michard et al, 2010a[Michard et al, , 2010b, and references therein].…”

“…It is also coeval with the magmatic activity and fluid circulations in the Jebilet as shown by the emplacement of cordierite-bearing granodiorites at~327 Ma (Rb-Sr isochrones, Mrini et al [1992]) and a granitic sill emplaced at~330 Ma (U-Pb zircon, [Essaifi et al, 2003]), together with sulphide deposits dated at~332 Ma by 40 Ar/ 39 Ar method on hydrothermal sericite [Marcoux et al, 2008]. These Carboniferous basins in Western Meseta are interpreted as foreland basins related to north-westward propagation of thrusts and folds [Ben Abbou et al, 2001;Roddaz et al, 2002], or intraplate extensional basins [Hoepffner et al, 2005[Hoepffner et al, , 2006b, and references therein]. Recently, Tahiri et al [2010] suggested that these basins can be opened during the southward docking of the Sehoul block against the Western Meseta.…”

“…A number of large-scale correlations between the Variscan Orogeny in Europe and northwestern Africa and the Alleghanian (Appalachian) belt in North America have been proposed [Arthaud and Matte, 1977;Piqué, 1981;Matte, 2001;Houari and Hoepffner, 2003;Hoepffner et al, 2005Hoepffner et al, , 2006aHoepffner et al, , 2006bSimancas et al, 2005;Engelder and Whitaker, 2006;Michard et al, 2008;Simancas et al, 2009;Hatcher, 2010]. Except for a few structural studies of the Appalachian orogeny in the eastern United States [e.g., Hatcher, 2010;Engelder and Whitaker, 2006] and in southern Europe [Edel et al, 2013;Weil et al, 2013], the early stages of deformation are not taken into account and most of the cited studies focus on late structures.…”