We present a methodology to describe fault geometry at different scales and to characterize the d... more We present a methodology to describe fault geometry at different scales and to characterize the distribution of these scales on the flanks of a salt intrusion in the Colorado Plateau (Arches National Park, United States). This methodology is based on the recognition of the physical ...
<p>Coastal wetlands play a strategic role in the context of mitigat... more <p>Coastal wetlands play a strategic role in the context of mitigating climate-change thanks to their ability of sequestering large amounts of organic carbon (C) and store it in the ground. However, methane (CH4) may form in the sediments of freshwater wetlands, so that these ecosystems may switch from a net sink to a net source of greenhouse gases (GHGs). Salinity is known to be one of the main inhibitors of CH4 production; however, its influence in brackish water systems is still poorly studied. Our study aims at understanding how the consequences of climate change (sea-level rise, salinization, and temperature increase) may affect the C storage in vegetated coastal wetlands.</p><p>Here we present the results of almost one year of measurements performed in four wetlands located along the northeast Adriatic coast near Ravenna, Italy. Despite a very limited distance among the four sites (1-4 km), they present a significant salinity gradient, going from fresh- to brackish waters. Air and soil temperatures and solar irradiance were continuously monitored through a network of sensors. Carbon dioxide (CO2) and CH4 fluxes from soils and waters, water head levels, surface, and ground water physical-chemical parameters (redox potential (Eh), temperature (T), pH, conductivity (EC), sulphate and sulfide concentrations) were measured monthly. Finally, soil samples were collected at each site in order to determine soil properties, i.e. organic matter content, bulk density, granulometry. </p><p>We used multivariate statistics to investigate emergent relationships between GHGs fluxes from water and soil and environmental factors. The results of the principal component analysis (PCA) suggest that air T, water T  and irradiance play a significant role in both CH4 and CO2 emissions from water and soil. On the other hand, water head level and EC have been found to be limiting factors of the GHGs emissions. Soil properties seem to be secondary factors both in soil and water emissions.</p><p>The results obtained from these and other analyses will be presented to provide a critical insight on correlations between GHGs emissions and the environmental drivers in temperate coastal wetlands. A remote-sensing approach to upscale the results obtained on the four studied wetlands, to the adjacent coastal wetland system will also be presented. Remote sensing turns out to be a key method to extend the assessment on C fluxes to areas difficult to access and that could not be characterized otherwise.</p>
Fieldtrip guidebook for the three itineraries of the 16th Rock Fracture Project meeting in the Ma... more Fieldtrip guidebook for the three itineraries of the 16th Rock Fracture Project meeting in the Majella Mountain
Deformation of porous carbonate grainstones takes generally place by compactive shear banding, wh... more Deformation of porous carbonate grainstones takes generally place by compactive shear banding, which initially produce single bands that may evolve during incremental strain into zones of multiple bands and, eventually, fault zones with discrete slip surfaces. The several processes associated to increased deformation are recorded in the aforementioned structural elements. In fact, they are characterized by a different texture, porosity, dimensional attributes (length, thickness, displacement). Fault zones are characterized by inner fault cores made of cataclastic material surrounded by thicker damage zones including single bands and zones of bands. In this work, we present the results of in situ permeability measurements carried out using a portable field permeameter along both normal and strike-slip fault zones developed in high-porosity carbonate grainstones from the Cretaceous Orfento Formation (Majella Mountain, Abruzzi Region), and in the Lower Pleistocene deposits (Favignana island, Sicily). We studied eight fault zones with displacement ranging from 30 centimeters to 2 meters. Undeformed rocks are poor-to-medium consolidated grainstone. Grains are made up of fragments of carbonates ranging from 0.05 to 1 mm in diameter. The matrix consists of bladed and sparry calcite cement and carbonate fragments smaller than 0.05 mm. Porosity is about 30%, bulk permeability in the order of about 5.6 Darcy. Grainstones in damage zones record nondestructive compactive granular flow and pore collapse, which reduce porosity and pore connectivity. Moreover intergranular pressure solution seams form in the already compacted rock. Permeability measurements show an average value of about 0.6 Darcy. Deformation in fault cores evolves from particulate flow to compactional cataclastic flow. The progressive grain size reduction increases the amount of silt- and clay-size fractions. Hence, porosity was dramatically reduced and the permeability values show an average value of 0.07 Darcy. The aforementioned permeability data indicate a three order of magnitude decrease of permeability from host rocks to cataclastic fault cores. A clear dependence of the fluid circulation paths through porous carbonates is therefore inferred at depth due to orientation, density and connectivity of the shear band fault zones. Accordingly, the results presented in this study may be helpful in applications such as geofluids management for improving the forecasting of carbonate reservoir quality and understanding the extent of reservoir compartmentalization
. Coastal wetlands are fundamental for climate-change mitigation thanks to their ability to store... more . Coastal wetlands are fundamental for climate-change mitigation thanks to their ability to store large amounts of organic carbon in the soil. They also represent the first natural emitter of methane (CH4). Salinity is known to inhibit CH4 production, but its effect in brackish ecosystems is still poorly understood. Our study aims to understand how environmental variables may affect greenhouse gas emissions (GHGs) in coastal temperate wetlands. We present the results of over one year of measurements performed in four wetlands located along a salinity gradient on the northeast Adriatic coast near Ravenna, Italy. Soil properties were determined by collecting soil samples, while carbon dioxide (CO2) and methane (CH4) fluxes from soils and standing waters, water levels, surface, and groundwater physical-chemical parameters (temperature, pH, electrical conductivity, and sulphate concentrations of water) were monthly monitored by a portable gas flux-meter and multiparametric probes, respectively. Principal component analysis (PCA) was used to investigate emergent relationships between GHGs fluxes and environmental variables. Our results suggest that, among all variables, temperature and irradiance play a significant role in CH4 emissions from water and soil whereas water column depth and salinity are limiting factors of GHGs emissions.
Abstract The permeability structure of a fault zone is strongly dependent on the occurrence of me... more Abstract The permeability structure of a fault zone is strongly dependent on the occurrence of meso-scale fracture patterns within the damage zone. Here, structural analyses of Virtual Outcrop Models (VOM) integrated with Discrete Fracture Network (DFN) modelling are used to constrain the relationship between meso-scale fracture patterns and the bulk permeability of a regional-scale fault zone. The Goddo Fault Zone (GFZ, Bomlo – Norway) is a long-lived extensional fault zone cutting across a granodioritic body developed during the long-lasting rifting of the North Sea. Fracture geometrical characteristics and the spatial variation of fracture intensity derived from VOM structural analysis were adopted as input for stochastic DFN models representing selected portions of the GFZ to constrain the variability of the structural permeability tensor K related to the mesoscopic fracture pattern. The intensity of fault-related fracture set(s), and the associated structural permeability computed with DFN models, likely exhibits a decreasing power-law trend within the damage zone with increasing distance from the fault cores. The orientation of the maximum K tensor component is controlled by the intersection direction of the dominant fracture sets. These results highlight the fundamental role of mesoscopic fracture patterns in controlling the bulk petrophysical properties of large fault zones.
We present a methodology to describe fault geometry at different scales and to characterize the d... more We present a methodology to describe fault geometry at different scales and to characterize the distribution of these scales on the flanks of a salt intrusion in the Colorado Plateau (Arches National Park, United States). This methodology is based on the recognition of the physical ...
<p>Coastal wetlands play a strategic role in the context of mitigat... more <p>Coastal wetlands play a strategic role in the context of mitigating climate-change thanks to their ability of sequestering large amounts of organic carbon (C) and store it in the ground. However, methane (CH4) may form in the sediments of freshwater wetlands, so that these ecosystems may switch from a net sink to a net source of greenhouse gases (GHGs). Salinity is known to be one of the main inhibitors of CH4 production; however, its influence in brackish water systems is still poorly studied. Our study aims at understanding how the consequences of climate change (sea-level rise, salinization, and temperature increase) may affect the C storage in vegetated coastal wetlands.</p><p>Here we present the results of almost one year of measurements performed in four wetlands located along the northeast Adriatic coast near Ravenna, Italy. Despite a very limited distance among the four sites (1-4 km), they present a significant salinity gradient, going from fresh- to brackish waters. Air and soil temperatures and solar irradiance were continuously monitored through a network of sensors. Carbon dioxide (CO2) and CH4 fluxes from soils and waters, water head levels, surface, and ground water physical-chemical parameters (redox potential (Eh), temperature (T), pH, conductivity (EC), sulphate and sulfide concentrations) were measured monthly. Finally, soil samples were collected at each site in order to determine soil properties, i.e. organic matter content, bulk density, granulometry. </p><p>We used multivariate statistics to investigate emergent relationships between GHGs fluxes from water and soil and environmental factors. The results of the principal component analysis (PCA) suggest that air T, water T  and irradiance play a significant role in both CH4 and CO2 emissions from water and soil. On the other hand, water head level and EC have been found to be limiting factors of the GHGs emissions. Soil properties seem to be secondary factors both in soil and water emissions.</p><p>The results obtained from these and other analyses will be presented to provide a critical insight on correlations between GHGs emissions and the environmental drivers in temperate coastal wetlands. A remote-sensing approach to upscale the results obtained on the four studied wetlands, to the adjacent coastal wetland system will also be presented. Remote sensing turns out to be a key method to extend the assessment on C fluxes to areas difficult to access and that could not be characterized otherwise.</p>
Fieldtrip guidebook for the three itineraries of the 16th Rock Fracture Project meeting in the Ma... more Fieldtrip guidebook for the three itineraries of the 16th Rock Fracture Project meeting in the Majella Mountain
Deformation of porous carbonate grainstones takes generally place by compactive shear banding, wh... more Deformation of porous carbonate grainstones takes generally place by compactive shear banding, which initially produce single bands that may evolve during incremental strain into zones of multiple bands and, eventually, fault zones with discrete slip surfaces. The several processes associated to increased deformation are recorded in the aforementioned structural elements. In fact, they are characterized by a different texture, porosity, dimensional attributes (length, thickness, displacement). Fault zones are characterized by inner fault cores made of cataclastic material surrounded by thicker damage zones including single bands and zones of bands. In this work, we present the results of in situ permeability measurements carried out using a portable field permeameter along both normal and strike-slip fault zones developed in high-porosity carbonate grainstones from the Cretaceous Orfento Formation (Majella Mountain, Abruzzi Region), and in the Lower Pleistocene deposits (Favignana island, Sicily). We studied eight fault zones with displacement ranging from 30 centimeters to 2 meters. Undeformed rocks are poor-to-medium consolidated grainstone. Grains are made up of fragments of carbonates ranging from 0.05 to 1 mm in diameter. The matrix consists of bladed and sparry calcite cement and carbonate fragments smaller than 0.05 mm. Porosity is about 30%, bulk permeability in the order of about 5.6 Darcy. Grainstones in damage zones record nondestructive compactive granular flow and pore collapse, which reduce porosity and pore connectivity. Moreover intergranular pressure solution seams form in the already compacted rock. Permeability measurements show an average value of about 0.6 Darcy. Deformation in fault cores evolves from particulate flow to compactional cataclastic flow. The progressive grain size reduction increases the amount of silt- and clay-size fractions. Hence, porosity was dramatically reduced and the permeability values show an average value of 0.07 Darcy. The aforementioned permeability data indicate a three order of magnitude decrease of permeability from host rocks to cataclastic fault cores. A clear dependence of the fluid circulation paths through porous carbonates is therefore inferred at depth due to orientation, density and connectivity of the shear band fault zones. Accordingly, the results presented in this study may be helpful in applications such as geofluids management for improving the forecasting of carbonate reservoir quality and understanding the extent of reservoir compartmentalization
. Coastal wetlands are fundamental for climate-change mitigation thanks to their ability to store... more . Coastal wetlands are fundamental for climate-change mitigation thanks to their ability to store large amounts of organic carbon in the soil. They also represent the first natural emitter of methane (CH4). Salinity is known to inhibit CH4 production, but its effect in brackish ecosystems is still poorly understood. Our study aims to understand how environmental variables may affect greenhouse gas emissions (GHGs) in coastal temperate wetlands. We present the results of over one year of measurements performed in four wetlands located along a salinity gradient on the northeast Adriatic coast near Ravenna, Italy. Soil properties were determined by collecting soil samples, while carbon dioxide (CO2) and methane (CH4) fluxes from soils and standing waters, water levels, surface, and groundwater physical-chemical parameters (temperature, pH, electrical conductivity, and sulphate concentrations of water) were monthly monitored by a portable gas flux-meter and multiparametric probes, respectively. Principal component analysis (PCA) was used to investigate emergent relationships between GHGs fluxes and environmental variables. Our results suggest that, among all variables, temperature and irradiance play a significant role in CH4 emissions from water and soil whereas water column depth and salinity are limiting factors of GHGs emissions.
Abstract The permeability structure of a fault zone is strongly dependent on the occurrence of me... more Abstract The permeability structure of a fault zone is strongly dependent on the occurrence of meso-scale fracture patterns within the damage zone. Here, structural analyses of Virtual Outcrop Models (VOM) integrated with Discrete Fracture Network (DFN) modelling are used to constrain the relationship between meso-scale fracture patterns and the bulk permeability of a regional-scale fault zone. The Goddo Fault Zone (GFZ, Bomlo – Norway) is a long-lived extensional fault zone cutting across a granodioritic body developed during the long-lasting rifting of the North Sea. Fracture geometrical characteristics and the spatial variation of fracture intensity derived from VOM structural analysis were adopted as input for stochastic DFN models representing selected portions of the GFZ to constrain the variability of the structural permeability tensor K related to the mesoscopic fracture pattern. The intensity of fault-related fracture set(s), and the associated structural permeability computed with DFN models, likely exhibits a decreasing power-law trend within the damage zone with increasing distance from the fault cores. The orientation of the maximum K tensor component is controlled by the intersection direction of the dominant fracture sets. These results highlight the fundamental role of mesoscopic fracture patterns in controlling the bulk petrophysical properties of large fault zones.
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Papers by Marco Antonellini