The Mid-Variscan Allochthon: Keys from correlation, partial retrodeformation and plate-tectonic reconstruction to unlock the geometry of a non-cylindrical belt

Abstract The non-cylindrical character of the Variscan Belt is established via a description of its most salient geological characteristics and correlations among the main and relatively minor massifs from Bohemia to Morocco on the basis of a bibliographical synthesis. Using the firmly established tectonostratigraphic domains, the continuity of Variscan zones is discussed, as well as the western termination of the one that occupies most of the central part of the belt. This zone is characterized by its allochthony, and breaks the continuity of the zonation, that is, the cylindrism of the belt. A proposal is made to call this zone the Mid-Variscan Allochthon and its wedge shape in map view is explained performing a step by step restoration of late Variscan deformation. Once the geometry of the belt is interpreted by a succession of regionally significant deformation events, a kinematic reconstruction is proposed. It is based on recent developments on the knowledge of Paleozoic plate tectonics and intended to show that the deformation model is compatible with current paleogeographical developments.