Southward extrusion tectonics during the Carboniferous Africa-North America collision

From the Devonian to the Permian, North America and Africa shared the same orogenic history involving plate convergence followed by continent-continent collision that closed the proto-Atlantic Ocean. Conventionally, it is held that this resulted in thrust and nappe tectonics with a westward vergence in the Appalachians and an eastward vergence in the Mauritanides. In contrast to the movement picture suggested by the thrusting model, medium to late Carboniferous displacements along major fault-zones are mainly dextral strike-slip in the southeastern Appalachians and sinistral in the western Mauritanides. An alternative kinematic model is presented here: it is suggested that the southern Appalachian Piedmont and western Senegal-Mauritania Provinces moved southward relative to North American and African cratons. This “escape” tectonics during continental collision would result from: 1.(1) a plate convergence vector oriented at a medium oblique angle to preexisting zones of weakness within the North American margin and,2.(2) indentation of the Appalachians by the Reguibat Uplift of West Africa.