Late Palaeozoic — Early Mesozoic Plate Reorganization: Evolution and Demise of the Variscan Fold Belt

Abstract

Closure of the Proto-Tethys Proto-Atlantic Ocean was diachronous along the Variscan-Appalachian fold belt. Collision of Gondwana and Laurussia commenced in Famennian-Visean time in the western Mediterranean domain and propagated during the Late Carboniferous westwards and eastwards. By Westphalian time the Proto-Atlantic was closed. In the European Variscan fold belt, orogenic activity terminated at the end of the Westphalian. Development of Stephanian-Autunian wrench-fault systems, dissecting the Variscan fold belt, can be related to a change in the convergence direction between Gond-wana and Laurussia during their terminal Alleghe-nian suturing phase. This was followed by a fundamental plate boundary reorganization and the development of a new tensional regime in the interior of Pangea. Late Permian and Triassic southward propagation of the Arctic-North-Atlantic rift system and westward propagation of the Tethys rift system involved tensional reactivation of Permo-Carbonif-erous crustal discontinuities. During the Mid-Jurassic a new divergent-transform plate boundary was established between Laurasia and Gondwana.