Abstract

The Mid-European Palaeozoic Belt is often considered as the result of a continuous continental convergence from late Silurian to Carboniferous. However, some stratigraphic, magmatic and structural data support a discontinuous evolution model. In late Silurian, the Eo-Variscan stage corresponds to a continental subduction responsible for a high pressure metamorphism. During their exhumation, the high pressure rocks are partly melted. In North Massif central, the Eo-Variscan rocks are already outcropping in Middle Devonian. Since that time, evidence for a calc-alkaline magmatic arc is found in the Massif central. Vosges and Massif armoricain. This arc is due to the southward subduction of the Rheic Ocean. Tensional events such as the Brevenne rift, ligne des klippes and Bolazec areas in Massif central. Vosges and Massif armoricain respectively occur in the upper plate. These lines of evidence show that the Medio-Variscan period is heterogeneous since extensional tectonics are followed by compressional ones belonging to the Hercynian Belt proper. Therefore, the Variscan belt results of two orogenic cycles.

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