The uranium metallogeny in the South Armorican detachment zones, Variscan belt, France: geology, tracing (in space and time), numerical modelling

Abstract : Uranium mineralization is common in geological environments where oxidized uranium bearing fluids interact with reduced lithologies. This was the case for Variscan detachments in the South Armorican Massif, France. Numerous syn-tectonic peraluminous granites were emplaced in the footwall of detachments during the Carboniferous. Surface-derived fluids infiltrated the detachment planes and leached out the uranium from the magmatic uraninite that crystallized in these granites at the end of magmatic differentiation. On their way back to the surface, these fluids interacted with reducing black schists, which triggered precipitation of hydrothermal uraninite. This conceptual model serves as a basis for thermal hydraulic-mechanical modeling.