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.