Attributes and influence on fluid flow of fractures in foreland carbonates of southern Italy

The geometrical and structural attributes of fractures and fracture networks affecting Mesozoic–Cenozoic, platform carbonates from foreland areas of southern Italy are qualitatively and quantitatively described. Fractures include faults, joints and fault-related solution cleavages. Two tectonic environments can be recognised: (1) the Apulian and Hyblean forebulge domains, consisting of broad foreland areas, where joints and rare, low-displacement, normal faults occur and (2) the Gargano strike-slip fault domain, where strike-slip faults and fault-related solution cleavages are the most ubiquitous structures. In both tectonic environments, orthogonal sets of sub-vertical fractures separate the beds into an assemblage of fracture-bound blocks commonly characterised by an orthorhombic symmetry and a centimetric-to-metric size. The general causes for the observed fractures are ascribed to the bending stress in the Apulian and Hyblean forebulge domains and to the strike-slip faulting in the Gargano area. Fracture attributes and distributions suggest that the rock permeability is markedly anisotropic in both tectonic environments.