In this paper we report on the results of a systematic study carried out on the fault and fracture systems exposed in the Majella Mountain, in the central Apennines fold and thrust belt of mainland Italy. The focus of our work was to assess the dimensional, spatial, and scaling properties of fault and fractures in carbonate rocks, in order to set up appropriate flow models for these types of potential geofluid reservoirs. The results provide information on (1) orientation, size distribution, density variations, and fractal characteristics of the fault and fracture networks affecting the Majella anticline; (2) the scaling properties and the overall architecture of different fault zone components; (3) the overprinting relationships between fault and fracture sets and the Majella fold structure. These data were used to elaborate a three-dimensional discrete fault and fracture model (DFFN model) of a ∼100 m3 geological volume, and for this to (1) evaluate the transport and storage properties of the reservoir; and (2) assess the degree of vulnerability and any possible hazard related to the exploitation and management of geofluids hosted in carbonate rock volumes.
The processes of brittle-ductile shear zone evolution and fault initiation by the coalescence of en echelon arrays of tensile cracks are quantitatively analysed in terms of displacement and temperature conditions at which they took place in very low-grade, well bedded micritic limestones from the southern Apennines, Italy. Three different types of structures are distinguished: (i) conjugate arrays of en echelon, calcite-filled tension gashes, showing extensional shear offsets; (ii) en echelon vein arrays showing incipient development of discontinuous shear-parallel fractures cutting through the tension gashes; and (iii) faulted vein arrays, in which vein array breaching by a continuous, discrete normal fault has occurred. Fluid inclusion microthermometry from vein calcite sampled from the different sets of structures (i) to (iii) above indicates that environmental conditions remained roughly constant during the different stages of vein array evolution and fault development, with average homogenization temperatures from primary fluid inclusions being in the range 130–140°C. Our results show how displacement accumulation and shear strain essentially control vein array evolution by rotation of en echelon tension gashes, fracture linkage and, eventually, fault nucleation, at approximately constant temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.