SOUTHERN MARGIN OF THE VARISCAN BELT - THE NORTH-WESTERN GONDWANA MOBILE ZONE (EASTERN MOROCCO AND NORTHERN ALGERIA)

Stratigraphic and structural correlations between the Palaeozoic massi fs of eastern Morocco and northern Algeria allow three tectonic domain s to be distinguished: (1) The cratonic zone, i.e. the West African pl atform which remained outside the Variscan chain and its peripherical margin (Moroccan Anti-Atlas and Algerian Ougarta); (2) a WSW-ENE trend ing zone, over 1 500 km from Marrakech to Kabylia and Calabria (in the ir assumed Palaeozoic location). - This zone was characterized during the Late Palaeozoic by a continuous instability indicated by the devel opment of successive turbiditic basins and a major orogeny at the Devo nian-Carboniferous boundary; and (3) central and western Morocco, whic h corresponds to the external zones of the European Hercynides. The Ma rrakech-Kabylia zone separates the Variscan domain from the stable and undeformed West African craton. During Early Palaeozoic times it bega n as an extensive or transtensive zone. It has been deformed by the La te Devonian orogeny and by Carboniferous and Permian reactivation. The zone represents the southern limit of the Hercynian chain and is dist inguished by its transcurrent regime throughout the Late Palaeozoic.