Abstract
Ductile shear zones represent sites of significant fluid circulation and hydrothermal alteration where metamorphic, magmatic and surface-derived fluids meet. Characterization of the meteoric source of crustal fluids can be used to better understand ore deposition and mineralization at the orogen scale or for stable isotope paleoaltimetry reconstructions. Microstructural, thermometry, geochronology and hydrogen isotope data conducted on syntectonic peraluminous granites from crustal-scale shear zones in the Armorican Massif and the French Massif Central allowed the determination of the source of fluids present during deformation, and a better understanding of the spatial and temporal evolution of localized deformation and fluid-rock interaction across these Variscan fossil hydrothermal systems, including the timing and duration of fluid flow and mineral water isotope exchange.