The Atlas-East Variscan -Elbe shear system and its role in the formation of the pull-apart Late Palaeozoic basins

Abstract

The Variscan orogeny occurred as a result of the Late Devonian to Late Carboniferous collision and accretion of Gondwana-derived microcontinents and continental masses with those of Laurussia. The irregular boundaries of the colliding continents caused isochronous transpressional and transtensional tectonics, accompanied by a complex pattern of intracontinental shear zones at the scale of the southern European Variscides. These shear zones and their configuration controlled the subsequent evolution of Permian to Middle Triassic paleogeography. The geographic distribution, from Morocco to the Eastern Alps, of the Late Carboniferous–Permian up to Triassic basins, most of which are considered as pull-apart basins, was related with the development of the Late Palaeozoic intracontinental shear network. Our analysis of the stratigraphic, tectonic and volcanic features of the Late Carboniferous/Permian continental basins across the Laurussia/Gondwana boundary reveals the role of the East Variscan Shear Zone during this time as a precursory lineament for the development of the Permian to Triassic rifting of Pangaea and the following opening of oceanic basins (e.g., the Neothetyan Ocean).