Ordovician magmatism in the Levezou massif (French Massif Central) tectonic and geodynamic implications
New U Pb dating on zircon yielded ca. 470 Ma ages for the granitoids from the Levezou massif in the southern French Massif Central. These new ages do not support the previous interpretation of these granitoids as syn tectonic intrusions emplaced during the Late Devonian Early Carboniferous thrusting. The geochemical and isotopic nature of this magmatism is linked to a major magmatic Ordovician event recorded throughout the European Variscan belt and related to extreme thinning of continental margins during a rifting event or a back arc extension. The comparable isotopic signatures of these granitoids on each side of the eclogite bearing leptyno amphibolitic complex in the Levezou massif, together with the fact that they were emplaced at the same time, strongly suggest that these granitoids were originally part of a single unit, tectonically duplicated by either isoclinal folding or thrusting during the Variscan tectonics.
International Journal of Earth Sciences