Faulting and deformation in chalk

In chalk, strong deformation at the grain level is associated with faulting. Within a 5-10 cm thick fringe on each side of normal faults, texture modifications were documented and analysed in samples from the Campanian White Chalk. We used SEM observations, image analysis, reconstruction of the porous media and physical measurements. Dissolution and cementation features, together with a reorganisation of the pore space, can be explained by massive fluid transfers. Faulting is interpreted as ductile shearing, which involves slip and dissolution first in shear deformation bands and then along a single fault plane.