Palaeozoic evolution of the Variscan Vosges Mountains
A geological synthesis of the Palaeozoic Vosges Mountains (NE France) is presented using existing observations and new data. The geodynamic evolution involves: (1) Early Palaeozoic sedimentation and magmatism; (2) Late Devonian subduction triggering back-arc spreading; (3) early Lower Carboniferous continental subduction, continent–continent collision and polyphase deformation and metamorphism of the orogenic root; and (4) late Lower Carboniferous orogenic collapse driven by thermal weakening of the middle crust. The evolution is integrated within the framework of the European Variscan Belt. The Northern Vosges comprise sediments of Rhenohercynian affinity separated from Teplá-Barrandian metasediments by a Lower Carboniferous magmatic arc. The latter is correlated with the Mid-German Crystalline Rise, and is ascribed to the south-directed subduction of the Rhenohercynian Basin. The Saxothuringian–Moldanubian suture is thought to be obliterated by the magmatic arc, while the Lalaye–Lubine Fault is interpreted as the Teplá-Barrandian–Moldanubian boundary. The Central Vosges are paralleled with the Moldanubian domain of the Bohemian Massif where identical lithologies record the Devonian–Carboniferous SE-directed subduction of the Saxothuringian passive margin below the Moldanubian upper plate. The Southern Vosges represent the upper Moldanubian crust and are linked to the southern Black Forest. The presence of an oceanic domain to the south of the Vosges–Black Forest remains unclear.