Imprint of the Reguibat Promontory (West Africa) on the Appalachian, Mauritanide and Souttoufide Belts During the Assembly of Pangaea

In the course of the Carboniferous to Permian assembly of Pangaea, large parts of eastern Laurussia and northern Gondwana were affected by the Variscan Orogeny. Here, we particularly focus on the Appalachian belt of eastern Laurentia and the Mauritanide, Western Thrust (WTB) and Souttoufide belts of the western West African Craton. Owing to the irregular shapes of the craton margins, this collision resulted in several conjugate promontories and embayments on both cratons. Among others, the coupled pair formed by the African “Reguibat promontory” and its counterpart in North America, the “Pennsylvania embayment” is in focus of this study. The (relative) western movement of the Reguibat Shield had initially imprinted the West African belts but finally also affected the Appalachians. Forming such a classical “punch mark” produces two specific stacks of “nappes” (lobes) on both sides of the promontory. Related to the Reguibat promontory, the southern NW-SW stacking nappes (e.g. Akjoujt nappes) are known since a long time. However, those nappes of the “Adrar Souttouf Massif” to the north have not been recognised before because of its N-S alignment instead of a symmetrical SW-NE direction. Furthermore, the Adrar Souttouf Massif is partially covered by allochthons terranes (WTB or Appalachians). This discovery justifies the application of the classical imprinting model to the deformation of the North American and African belts by westward moving of the Reguibat Shield.