Papers by Marco Antonellini
Coupled human-water system dynamics of saltwater intrusion in the low coastal plain of the Po River, Ravenna, Italy
The EGU General Assembly, Apr 1, 2017
Effect of Faulting on Fluid Flow in Porous Sandstones: Geometry and Spatial Distribution
AAPG Bulletin, 1995
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 ...

Exploring the driving factors of CH4 and CO2 emissions in coastal wetlands: a case study in the Ravenna Province, Italy
<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>
Scaling Laws of Fracture Network Properties in Crystalline Rock: a Powerful Approach to the Characterization of Unconventional Geofluids Reservoirs
The rock fracture project workshop and fieldtrip on fracturing and faulting in carbonate rocks
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 mechanism and hydraulic properties of normal and strike-slip fault zones in porous carbonates outcropping in central and southern Italy
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

Marine and Petroleum Geology, Jul 1, 2020
Deformation bands and structurally-related diagenetic heterogeneities, here named Structural Diag... more Deformation bands and structurally-related diagenetic heterogeneities, here named Structural Diagenetic Heterogeneities (SDH), have been recognized to affect subsurface fluid flow on a range of scales and potentially promoting reservoir compartmentalization, influencing flow buffering, and sealing during production. Their impact on reservoir hydraulic properties depends on many factors, such as their permeability contrast with respect to the undeformed reservoir rock, their anisotropy, thickness, geometry as well as their physical connectivity and arrangement in the subsurface. We used the Ground Penetrating Radar (GPR) for detection and analysis of the assemblage of deformation bandscarbonate nodules, in high-porosity arkose sandstone in Northern Apennines of Italy. 2D GPR surveys allowed the description of the SDH spatial organization, their geometry, and their continuity in the subsurface. Petrophysical (air-permeability) and mechanical (uniaxial compressive strength) properties of host rock, deformation bands, and calcite-cement nodules were evaluated along a 30-m thick stratigraphic log to characterize the permeability and strength variations of those features. The assemblage "deformation bandsnodules" degrade porosity and permeability and produce a strengthening effect of the rock volume, imparting a strong mechanical and petrophysical heterogeneity to the pristine rock. Different textural, petrophysical, and geomechanical properties between deformation bands, nodules, and host rock result in different GPR response (permittivity). Thus, GPR response could be used to extend outcrop data (petrophysical and geomechanical) of SDH to 3D subsurface volumes in a way to reconstruct realistic and detailed outcrop analogs of faulted aquifers and reservoirs in porous sandstones.

Journal of Hydrology, Dec 1, 2015
Salinization of shallow coastal aquifers is particularly critical for ecosystems and agricultural... more Salinization of shallow coastal aquifers is particularly critical for ecosystems and agricultural activities. Management of such aquifers is an open challenge, because predictive models, on which science-based decisions are to be made, often fail to capture the complexity of relevant natural and anthropogenic processes. Complicating matters further is the sparsity of hydrologic and geochemical data that are required to parameterize spatially distributed models of flow and transport. These limitations often undermine the veracity of modeling predictions and raise the question of their utility. As an alternative, we employ data-driven statistical approaches to investigate the underlying mechanisms of groundwater salinization in low coastal plains. A time-series analysis and auto-regressive moving average models allow us to establish dynamic relations between key hydrogeological variables of interest. The approach is applied to the data collected at the phreatic coastal aquifer of Ravenna, Italy. We show that, even in absence of long time series, this approach succeeds in capturing the behavior of this complex system, and provides the basis for making predictions and decisions.
Failure modes in basin carbonates and their impact on fault development, Majella Mountain, central Italy

Driving and limiting factors of CH<sub>4</sub> and CO<sub>2</sub> emissions from coastal brackish-water wetlands in temperate regions
. 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.

Mud volcanoes are fluid escape structures allowing for surface venting of hydrocarbons (mostly ga... more Mud volcanoes are fluid escape structures allowing for surface venting of hydrocarbons (mostly gas but also liquid condensates and oils) and water-sediment slurries. For a better understanding of mud volcano dynamics, the characterization of the fluid dynamics within mud volcano conduits; the presence, extent, and depth of the fluid reservoirs; and the connection among aquifers, conduits, and mud reservoirs play a key role. To this aim, we performed a geoelectrical survey in the Nirano Salse Regional Nature Reserve, located at the edge of the northern Apennines (Fiorano Modenese, Italy), an area characterized by several active mud fluid vents. This study, for the first time, images the resistivity structure of the subsoil along two perpendicular cross sections down to a depth of 250 m. The electrical models show a clear difference between the northern and southern sectors of the area, where the latter hosts the main discontinuities. Shallow reservoirs, where fluid muds accumulate, are spatially associated with the main fault/fracture controlling the migration routes associated with surface venting and converge at depth towards a common clayey horizon. There is no evidence of a shallow mud caldera below the Nirano area. These findings represent a step forward in the comprehension of the Nirano Salse plumbing system and in pinpointing local site hazards, which promotes safer tourist access to the area along restricted routes.

Constraints upon fault zone properties by combined structural analysis of virtual outcrop models and discrete fracture network modelling
Journal of Structural Geology, Nov 1, 2021
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.
Il Ruolo Delle Bande DI Deformazione e Delle Stiloliti Nello Sviluppo Delle Faglie in Grainstones Carbonatici, Montagna Della Majella, Italia Centrale
Structure, architecture, and rock physical properties of basins-bounding normal faults in central Italy
Failure modes in basinal carbonates deposits: a case study from the Majella mountain area (central Apennines, Italy)
Fault development in Monte Conero (Italy) as a process of creating fracture porosity and permeability in carbonate rock
Monte Conero is an asymmetric anticline on the Adriatic coast in the Marche Region, Italy.....
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Papers by Marco Antonellini