Abstract
Normal fault zones affecting the pre-rift limestones in the Corinth rift comprise breccia layers separated by slip surfaces, but also numerous stylolites and calcite veins attesting the importance of aseismic fluid-driven mass transfer in fault activity. Cathodoluminescence microscopy shows that external (meteoric?) water circulated in the fault zones, whereas mass transfer in the surrounding rocks implied a closed system with water chemically equilibrated with the host-limestone. From these observations, we propose preliminary models of structural development and fluid flow in active fault zones in superficial conditions, with a tendency to concentration of deformation and fluid flow related to fault tip propagation.