ABSTRACT The Italian geodetic infrastructure in Antarctica has been constantly developed during t... more ABSTRACT The Italian geodetic infrastructure in Antarctica has been constantly developed during the last two decades. The integration of geodetic instruments with other geophysical sensors has been driving the planning and design of the geodetic infrastructure at Mario Zucchelli Station (MZS) and in a wide area around the base. Our purpose is to maximize the interdisciplinary use of the geodetic observations and to widen the field of investigation. The first geodetic GPS network was established in the area of Mt. Melbourne in the late 80s to study the local movement and deformation of the volcanic cone. A wider geodetic network was materialized on rocky outcrops in 1999-2000 with the purpose to study crustal deformations in the Northern Victoria Land (NVL). The project, named VLNDEF (Victoria Land Network for DEFormation Control), also aims at colleting measurements to constrain Glacial Isostatic Adjustment (GIA) models. VLNDEF is formed by 28 points that are accessible by means of helicopter, the maximum distance of points from the Italian base MZS being about 500 km. A permanent GPS station (TNB1) was installed in 1998 at MZS with DOMES N. 66036M001. In addition, to increase redundancy in the long term observations at MZS, an additional permanent GPS station TNB2 was installed in 2008 on a marker materialized a couple of years earlier and a few meters apart from TNB1. In addition, during 2008 three semi permanent remote stations were installed: VL01 (Cape Hallett), VL05 (Cape Philips), VL18 (Starr Nunatak). They are powered by a set of batteries and solar panels and provide a few months of data every year. Since its establishment, VLNDEF has been surveyed ten times, of which three are surveys of the whole network. GPS measurements are the core of the Italian geodetic infrastructure and are complemented by tide gauge measurements (since 2006), radiosoundings (during the Austral summer), on-ground meteorological parameters, episodic absolute and relative gravity measurements, geomagnetic field measurements and other geophysical observations. The deformation patterns obtained with GPS observations over the VLNDEF network are coupled with the data acquired during the geological and geomorphological surveys; the set of observations is used to study the neo-tectonics of NVL. We present the most recent geodetic results derived from the VLNDEF GPS data set and a recent cinematic model of the whole area. We present the preliminary geoid model in the northern part of the network.
Journal of Volcanology and Geothermal Research, 1999
The Tyrrhenian margin of Central Italy underwent extension during Pliocene and Quaternary. Extens... more The Tyrrhenian margin of Central Italy underwent extension during Pliocene and Quaternary. Extension occurred mainly through NW-SE normal faults, bordering a sequence of Plio-Quaternary basins. These basins are offset by coeval NE-SW faults, which show strike-slip and normal motions and have been interpreted as transfer faults. Plio-Quaternary volcanic activity along the margin occurred along a NW-SE belt, systematically in correspondence with NE-SW transverse systems.
We studied the nucleation and growth of cataclastic fault cores from fractured damage zones in ex... more We studied the nucleation and growth of cataclastic fault cores from fractured damage zones in extensional and strike-slip fault zones in carbonate rocks. Analysed fault zones have similar protolith lithology and sedimentary fabric, but different geometry, kinematics, size, tectonic ...
The evolution of deformation patterns during thrust-related folding is of importance for both ind... more The evolution of deformation patterns during thrust-related folding is of importance for both industrial and academic purposes because of the control that it exerts on the migration and accumulation of fluids in reservoirs. The link between structural position and deformation pattern has been described in both theoretical and field works. On the other hand, the well-documented dependence of deformation structures on the mechanical rock properties and on the environmental conditions indicates that, during folding, structural, stratigraphic, and environmental variables interact to control the deformation pattern within folds. In this work we describe the deformation pattern of the Mt. Catria anticline (Northern Apennines, Italy) and we investigate its variability with (1) the across-strike structural position, and (2) the rock type in the same structural position. Point (1) allowed us to identify and use the syn-folding deformation structures to constrain the fold kinematics. The result of point (2) analyses allowed us to divide the exposed Umbro-Marchean multilayer into three major mechanical units characterised by specific deformation mechanisms and patterns.
Starting from Pliocene times, the Apulian foreland in southern Italy has undergone a flexural pro... more Starting from Pliocene times, the Apulian foreland in southern Italy has undergone a flexural process underneath the Apennines thrust-fold belt. Mesozoic carbonate beds from the exposed Apulian forebulge are intensely dissected by systematic vertical joints striking parallel to the NW-trending flexure hinge. The sedimentary cover involved in the flexure consists of a 5.5 km thick succession of Mesozoic-Cenozoic carbonate beds
Geological Society, London, Special Publications, 2011
... The reactivation of faults is recorded as far south as the Zalla Graben, where continental-ri... more ... The reactivation of faults is recorded as far south as the Zalla Graben, where continental-rifting-related volcanism in the Jebel Al Haruj is ... However, these two stations are both on the western flank of the Pelagian block; their relative motion does not therefore describe the current ...
The sector of Antarctica facing Australia east of 139 °E is characterized by the abundance of exc... more The sector of Antarctica facing Australia east of 139 °E is characterized by the abundance of exceptionally long oceanic fracture zones that are collinear to post-rift right-lateral strike–slip fault systems developed at the northeastern edge of the Antarctic continent. High-resolution reflection seismic profiles indicate recent strike–slip activity at the southeastern edge of the Balleny Fracture Zone, similar to what is observed
The evolution of fracturing and cataclasis influences the mechanical and permeability properties ... more The evolution of fracturing and cataclasis influences the mechanical and permeability properties of fault zones. Fault zones can behave as strong or weak mechanical discontinuities and as conduits or barriers to fluid flow mainly depending on the nature and amount of cataclastic rocks that developed in their cores. Our structural investigations in fault zones affecting carbonate platform rocks in the Apennines, Italy, allow us to propose an evolutionary model for the progressive development of cataclastic fault core rocks from damage zones, and for the progression of cataclasis in fault cores. Analyses of particle size in the cataclastic rocks show power law distributions with fractal dimensions spanning over a broad range. This suggests that the idea of a persistent fragmentation mechanism (self-similar cataclasis) for describing the entire evolution of natural cataclastic fault cores in carbonate rocks is inadequate. Self-similar evolution for the cataclastic process is a concept mainly derived from laboratory experiments and micromechanical modelling. Conversely, we propose that the fragmentation mechanism progressively changes with the intensity of comminution. Slip localisation within narrow shear bands is favoured when a favourable cataclastic fabric with fractal dimensions D ˜ 2.6-2.7 is achieved in the fault zone. Intense comminution in the narrow shear zones produces the preferential formation of small diameter particles resulting in particle size distributions characterised by D-values approaching or exceeding 3. The progression pathway of fracturing in damage zones and the non self-similar evolution of cataclasis in fault rocks have an important impact on the frictional and permeability properties of fault zones.
The three-dimensional distribution of cataclastic rocks along faults deeply influences their mech... more The three-dimensional distribution of cataclastic rocks along faults deeply influences their mechanical and permeability properties. Despite their importance for seismic hazard and fluid flow, physical parameters controlling location of cataclastic rocks are still poorly constrained. We present results of three-dimensional numerical models specifically implemented for investigating the role of physical parameters enhancing the formation and location of cataclastic rocks along faults. Seven favourable conditions have been identified: failure under uniaxial stress conditions; failure by residual stress; failure by stress drop; interference of differently-oriented fracture populations, block rotation; fracturing of a previously fractured material, and rock anisotropy. Their weighted combination with boundary conditions including the geometry and kinematics of the fault surface, the overburden, the regional and kinematic stress fields, the rock rheology and strength, and pore fluid pressure, provide a scalar value proportional to the relative probability of cataclasis along the fault. Such a scalar value is named cataclasite generation function. The predictive capability of this numerical tool has been successfully tested in seven field sites in the Apennines, where fault zones in carbonate rocks are well exposed.
ABSTRACT The Italian geodetic infrastructure in Antarctica has been constantly developed during t... more ABSTRACT The Italian geodetic infrastructure in Antarctica has been constantly developed during the last two decades. The integration of geodetic instruments with other geophysical sensors has been driving the planning and design of the geodetic infrastructure at Mario Zucchelli Station (MZS) and in a wide area around the base. Our purpose is to maximize the interdisciplinary use of the geodetic observations and to widen the field of investigation. The first geodetic GPS network was established in the area of Mt. Melbourne in the late 80s to study the local movement and deformation of the volcanic cone. A wider geodetic network was materialized on rocky outcrops in 1999-2000 with the purpose to study crustal deformations in the Northern Victoria Land (NVL). The project, named VLNDEF (Victoria Land Network for DEFormation Control), also aims at colleting measurements to constrain Glacial Isostatic Adjustment (GIA) models. VLNDEF is formed by 28 points that are accessible by means of helicopter, the maximum distance of points from the Italian base MZS being about 500 km. A permanent GPS station (TNB1) was installed in 1998 at MZS with DOMES N. 66036M001. In addition, to increase redundancy in the long term observations at MZS, an additional permanent GPS station TNB2 was installed in 2008 on a marker materialized a couple of years earlier and a few meters apart from TNB1. In addition, during 2008 three semi permanent remote stations were installed: VL01 (Cape Hallett), VL05 (Cape Philips), VL18 (Starr Nunatak). They are powered by a set of batteries and solar panels and provide a few months of data every year. Since its establishment, VLNDEF has been surveyed ten times, of which three are surveys of the whole network. GPS measurements are the core of the Italian geodetic infrastructure and are complemented by tide gauge measurements (since 2006), radiosoundings (during the Austral summer), on-ground meteorological parameters, episodic absolute and relative gravity measurements, geomagnetic field measurements and other geophysical observations. The deformation patterns obtained with GPS observations over the VLNDEF network are coupled with the data acquired during the geological and geomorphological surveys; the set of observations is used to study the neo-tectonics of NVL. We present the most recent geodetic results derived from the VLNDEF GPS data set and a recent cinematic model of the whole area. We present the preliminary geoid model in the northern part of the network.
Journal of Volcanology and Geothermal Research, 1999
The Tyrrhenian margin of Central Italy underwent extension during Pliocene and Quaternary. Extens... more The Tyrrhenian margin of Central Italy underwent extension during Pliocene and Quaternary. Extension occurred mainly through NW-SE normal faults, bordering a sequence of Plio-Quaternary basins. These basins are offset by coeval NE-SW faults, which show strike-slip and normal motions and have been interpreted as transfer faults. Plio-Quaternary volcanic activity along the margin occurred along a NW-SE belt, systematically in correspondence with NE-SW transverse systems.
We studied the nucleation and growth of cataclastic fault cores from fractured damage zones in ex... more We studied the nucleation and growth of cataclastic fault cores from fractured damage zones in extensional and strike-slip fault zones in carbonate rocks. Analysed fault zones have similar protolith lithology and sedimentary fabric, but different geometry, kinematics, size, tectonic ...
The evolution of deformation patterns during thrust-related folding is of importance for both ind... more The evolution of deformation patterns during thrust-related folding is of importance for both industrial and academic purposes because of the control that it exerts on the migration and accumulation of fluids in reservoirs. The link between structural position and deformation pattern has been described in both theoretical and field works. On the other hand, the well-documented dependence of deformation structures on the mechanical rock properties and on the environmental conditions indicates that, during folding, structural, stratigraphic, and environmental variables interact to control the deformation pattern within folds. In this work we describe the deformation pattern of the Mt. Catria anticline (Northern Apennines, Italy) and we investigate its variability with (1) the across-strike structural position, and (2) the rock type in the same structural position. Point (1) allowed us to identify and use the syn-folding deformation structures to constrain the fold kinematics. The result of point (2) analyses allowed us to divide the exposed Umbro-Marchean multilayer into three major mechanical units characterised by specific deformation mechanisms and patterns.
Starting from Pliocene times, the Apulian foreland in southern Italy has undergone a flexural pro... more Starting from Pliocene times, the Apulian foreland in southern Italy has undergone a flexural process underneath the Apennines thrust-fold belt. Mesozoic carbonate beds from the exposed Apulian forebulge are intensely dissected by systematic vertical joints striking parallel to the NW-trending flexure hinge. The sedimentary cover involved in the flexure consists of a 5.5 km thick succession of Mesozoic-Cenozoic carbonate beds
Geological Society, London, Special Publications, 2011
... The reactivation of faults is recorded as far south as the Zalla Graben, where continental-ri... more ... The reactivation of faults is recorded as far south as the Zalla Graben, where continental-rifting-related volcanism in the Jebel Al Haruj is ... However, these two stations are both on the western flank of the Pelagian block; their relative motion does not therefore describe the current ...
The sector of Antarctica facing Australia east of 139 °E is characterized by the abundance of exc... more The sector of Antarctica facing Australia east of 139 °E is characterized by the abundance of exceptionally long oceanic fracture zones that are collinear to post-rift right-lateral strike–slip fault systems developed at the northeastern edge of the Antarctic continent. High-resolution reflection seismic profiles indicate recent strike–slip activity at the southeastern edge of the Balleny Fracture Zone, similar to what is observed
The evolution of fracturing and cataclasis influences the mechanical and permeability properties ... more The evolution of fracturing and cataclasis influences the mechanical and permeability properties of fault zones. Fault zones can behave as strong or weak mechanical discontinuities and as conduits or barriers to fluid flow mainly depending on the nature and amount of cataclastic rocks that developed in their cores. Our structural investigations in fault zones affecting carbonate platform rocks in the Apennines, Italy, allow us to propose an evolutionary model for the progressive development of cataclastic fault core rocks from damage zones, and for the progression of cataclasis in fault cores. Analyses of particle size in the cataclastic rocks show power law distributions with fractal dimensions spanning over a broad range. This suggests that the idea of a persistent fragmentation mechanism (self-similar cataclasis) for describing the entire evolution of natural cataclastic fault cores in carbonate rocks is inadequate. Self-similar evolution for the cataclastic process is a concept mainly derived from laboratory experiments and micromechanical modelling. Conversely, we propose that the fragmentation mechanism progressively changes with the intensity of comminution. Slip localisation within narrow shear bands is favoured when a favourable cataclastic fabric with fractal dimensions D ˜ 2.6-2.7 is achieved in the fault zone. Intense comminution in the narrow shear zones produces the preferential formation of small diameter particles resulting in particle size distributions characterised by D-values approaching or exceeding 3. The progression pathway of fracturing in damage zones and the non self-similar evolution of cataclasis in fault rocks have an important impact on the frictional and permeability properties of fault zones.
The three-dimensional distribution of cataclastic rocks along faults deeply influences their mech... more The three-dimensional distribution of cataclastic rocks along faults deeply influences their mechanical and permeability properties. Despite their importance for seismic hazard and fluid flow, physical parameters controlling location of cataclastic rocks are still poorly constrained. We present results of three-dimensional numerical models specifically implemented for investigating the role of physical parameters enhancing the formation and location of cataclastic rocks along faults. Seven favourable conditions have been identified: failure under uniaxial stress conditions; failure by residual stress; failure by stress drop; interference of differently-oriented fracture populations, block rotation; fracturing of a previously fractured material, and rock anisotropy. Their weighted combination with boundary conditions including the geometry and kinematics of the fault surface, the overburden, the regional and kinematic stress fields, the rock rheology and strength, and pore fluid pressure, provide a scalar value proportional to the relative probability of cataclasis along the fault. Such a scalar value is named cataclasite generation function. The predictive capability of this numerical tool has been successfully tested in seven field sites in the Apennines, where fault zones in carbonate rocks are well exposed.
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Papers by F. Salvini