The eastern termination of the Variscides: terrane correlation and kinematic evolution

Abstract

AbstractAnalysis of tectonostratigraphic units in the West Sudetes reveals the same geological events as in the areas west of the Elbe Fault Zone: a late Proterozoic (Cadomian) orogenic event, Cambro-Ordovician to Devonian rift-drift, and late Devonian to early Carboniferous subduction-collision. There is no conclusive evidence of an Ordovician orogenic event. Tectonic units in the Sudetes are shown to be related to terranes defined in western parts of the Bohemian Massif. The Lausitz-Izera Block, the Orlica-Śnieżnik Unit and the Staré Město Belt represent easterly continuations of the Saxo-Thuringian Terrane. The Rudawy Janowickie Unit and the Sudetic Ophiolite contain fragments of the Saxo-Thuringian Ocean. The protoliths of the Görlitz-Kaczawa Unit, the South Karkonosze Unit, the Góry Sowie and the Kłodzko Units either belong to the Bohemian Terrane or else were welded onto it during mid-late Devonian metamorphism and deformation. Relicts of the Saxo-Thuringian Foreland Basin are marked by flysch with olistoliths in the Görlitz-Kaczawa Unit and in the Bardo Basin. The spatial array of terranes in and around the Bohemian Massif reveals a disrupted orocline, dissected by dextral transpression along the Moldanubian Thrust. This orocline was formed when central parts of the Variscan belt were accommodated in an embayment of the southern margin of the Old Red Continent.