The Ghomarides Nappes, Rif Coastal Range, Morocco: A Variscan chip in the Alpine Belt

摘要

The Ghomarides nappes are the uppermost basement nappes in the Rifan Alpine belt. Paleozoic rocks constitute the prominent part of these nappes, together with Triassic and younger cover sediments. Four nappes are distinguished, each one with a distinct stratigraphical sequence, especially for the Devonian and Carboniferous periods. Sedimentological and structural arguments plead for an initial location on the northern margin of the African continent. The main folding and metamorphic events are shown to be Eo‐Variscan (late Acadian). Tectonic vergence was to the north (present coordinates). Late Variscan (Hercynian) shortening gave upright, NW‐SE trending folds. Alpine ductile overprints are scarce except at the base of the lowest nappe where K/Ar phengite ages are about 25 Ma. The Ghomarides nappes correlate with the Malaguides nappes (Betic Cordilleras, southern Spain), the Kabylian (northern Algeria) and Calabrian (southern Italy) Paleozoic nappes, the Tuscan‐South‐Alpine basement and the Upper Austro‐Alpine nappes. The proposed correlations allow us to restaure the southern margin of the Hercynian belt along northweste