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A pavement outcrop with excellent exposure of spatial relationships among joints, veins, small offset normal faults, and associated alteration halos (redox fronts) provided an opportunity to compare predictions of analytical models for reaction front propagation in a fracture-matrix system with a real-field situation. The results have important implications for fluid flow and pollutant transport through a fractured medium. The alteration halos observed suggest that all joints of different sets and most small faults are conductive to meteoric water at shallow depth. On the other hand, veins are local barriers to mass transport by diffusion. By using petrologic and petrophysical data, analytical modeling, and the width of the alteration halos, it was possible to estimate when the fracture network was open to fluid flow. The inferred time for fluid flow and diffusion through the fracture network is sensitive to the porosity n of the rock matrix used in the analytical solutions: 2200 ± 500 years with n = 0.08, 4600 ± 900 years with n = 0.05, and 16,000 ± 4000 with n = 0.02. The second and third age determinations are consistent with the landscape evolution of the area since the end of the last Wűrmian ice age and with the timing required to fill the fractures observed in outcrop. We suggest that analytical modeling is an important tool for the determination of transport and reaction time scales in fractured formations where it is constrained by a robust petrophysical and chemical properties data set.

Nell'ambito dello studio dell'intrusione d'acqua salata nell'acquifero freatico costiero del Comune di Cervia, la creazione di una carta delle isofreatiche è stata particolarmente difficile a causa della mancanza di una topografia del territorio dettagliata e aggiornata e d'informazioni omogenee e recenti relativamente alla profondità della falda. Le uniche informazioni disponibili si riferiscono al rilievo topografico del 1978 e a dati freatimetrici relativi al 1994, troppo vecchi se si considera che l'area investigata si colloca in una zona con forti tassi di subsidenza (maggiore di 2 mm/anno) e caratterizzata da enormi trasformazioni indotte sia dalle opere di bonifica sia dall'enorme sviluppo urbanistico e turistico. Un nuovo rilievo topografico di dettaglio e il monitoraggio della falda su base GIS, hanno permesso di creare una carta delle isofreatiche aggiornata e precisa, da cui identificare e localizzare la presenza di acqua salata nell'acquifero superficiale. L'importanza della precisione topografica è stigmatizzata dal fatto che la profondità della superficie di separazione fra acque dolci e salate, secondo la legge di Ghyben-Herzberg, è circa 40 volte l'altezza del livello freatico sopra il livello del mare. Una errore di pochi centimetri nella stima di quest'altezza si traduce in un errore 40 volte superiore nella localizzazione della superficie di separazione. Molte delle quote topografiche nel nuovo rilievo si sono rilevate sotto il livello del mare o in prossimità di esso e le quote freatiche sono raramente, se non nelle zone dunari e nei mesi invernali, sopra il livello del mare. I nuovi rilievi sono consistenti con i dati di conducibilità elettrica che mostrano un acquifero prevalentemente salato. During the characterization of the Salt-water intrusion in the freatic aquifer of Cervia, we had many problems in reconstructing the water table maps, because of the lack of an updated topography of the territory The only available information refer to the topographical survey of 1978 and to water table depths data going back to 1994, too old considering that the investigated area is placed in a strong subsidence region (larger than 2 mm/year). A new detailed topographical survey and aquifer monitoring, integrated within a GIS, allowed to construct new precise and updated water table maps that characterize the actual condition of salt water intrusion in the aquifer. The importance of topographical precision stems from the fact that the salt water – fresh water interface depth, as stated by the Ghyben-Herzberg relationship, is approximately 40 times the height of water table above sea level. An error of a few centimeters in estimating this height translates in an error 40 times larger in estimating the saltwater/freshwater interface depth. Most of the topography in this area is now placed below sea level or in its proximity and the freatic level is very rarely above it. The new water table maps are consistent with the electric conductivity data that show an aquifer almost completely salty

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.

Dune characterization in coastal zones is important for planning coastal defenses, groundwater management, and tourism development. Dune protection should be one of the main goals of any Integrated Coastal Zone Management Plan (ICZM). Coastal dunes efficiently oppose saltwater intrusion: their topographic elevation and their excellent infiltration capacity provide freshwater recharge and a hydraulic head that protect from saline intrusion according to the Ghyben-Herzberg principle (Fetter, 2001). The lateral continuity of the dunes system is also important for creating a continuous freshwater lens along the coast. As part of the Interreg IIIc Beachmed – “PosiDune project”, a monitoring campaign for groundwater levels and quality is being conducted on some test sites along stretches of the Ravenna coast: P.to Corsini, Marina Romea, Marina di Ravenna, Bevano river mouth. Dunes are still preserved in these areas and they act as natural defenses against storms, erosion and wave attack (Caruso et al., 2004; Caruso et al. 2006). A monitoring network has been established in each test site by placing piezometers both on the back and the crest of the dune and by carrying out a VES (Vertical Electri Sounding) geophysical campaign. The two methods (giving the chance to compare direct – piezometers - and indirect – geoelectric - data) has allowed to characterize the thickness of the fresh groundwater lens and the depth of the freshwater-saltwater interface. These actions have been integrated using: 1. a G.I.S. for data management; 2. a topographic and bathymetric reconstruction of the area using a LIDAR (Light detection and Ranging) survey; 3. a systematic seasonal update of the topography base and geomorphology using DGPS and theodolite surveys; 4. a survey of the geomorphologic evolution of the area through the periodical (monthly) acquisition of aerial images (flight height at 300m). The techniques employed are aimed at a precise charactetrization of the morphologic and hydrogeologic framework of the study areas. In addition, the maintenance of the monitoring system in future years will allow a better understanding of the effects of vegetation, dune restoration, and climate change to coastal hydrology and to ecosystem development (Gabbianelli & Sangiorgi, 2004; Ranjan et al. 2006). A clear comprehension of the role of dunes, achieved with this project, will be helpful for the management of the sites studied, especially considering their naturalistic values and peculiarities (they all belong to the Ramsar Zones list, SIC/ZPS sites list, Regional Po Delta Park – Emilia Romagna Region areas)

The roman time S. Vitale forest near Ravenna represents an historical landmark in the Po Plain. Today, the forest is surrounded by the complex urban system of Ravenna, by the city industrial infrastructure, and by the waterworks of the agricultural drainage system. Several natural and anthropogenic features threaten this area: • Saltwater intrusion in the freatic aquifer and seawater encroachment inland along the rivers. • Natural and anthropogenic land subsidence (caused by gas and deep groundwater winning, mostly after 1950). • Direct contamination from water bodies open to sea. • Destruction of coastal dunes and reduction of its barrier effect. • Land reclamation drainage system. • Insufficient aquifer recharge. • Sea level rise. Land subsidence has dropped most of the territory below mean sea level and it has modified the river regime and the normal groundwater flow. A drainage system is necessary to lower the phreatic level and keep dry the agricultural land. A second objective of the drainage system is to keep above the watertable the roots of the trees in the coastal areas. The result of the drainage system management, however, is an unstable freatic aquifer that is not able to contrast saltwater intrusion and is not helping much to maintain healthy the pinewood forests, that are also very sensitive to salinity.

Hypogene dissolution-precipitation processes strongly affect the petrophysical properties of carbonate rocks and fluid migration pathways in sedimentary basins. In many deep carbonate reservoirs, hypogene cavernous voids are often associated with silicified horizons. The diagenesis of silica in carbonate sequences is still a poorly-investigated research topic. Studies exploring the complexity of silica dissolution-precipitation patterns in hypogene cave analogues are therefore fundamental to unravel the diagenetic and speleogenetic processes that may affect this kind of reservoir. In this work, we investigated an exhumed and silicified Neoproterozoic carbonate sequence in Brazil hosting a 1.4 km-long cave. Quartz mineralization and silicified textures were analyzed with a multidisciplinary approach combining petrography, fluid inclusion microthermometry, silicon-oxygen stable isotope analyses and U-Th-Pb dating of monazite crystals. We found that an early silicification event caused the replacement of the dolostone layers with micro-crystalline quartz forming chert nodules. This event was likely associated with mixing fluids (ancient Neoproterozoic seawater and hydrothermal solutions sourced from the underlying Mesoproterozoic basement) at relatively low temperatures (ca. 50-100 degrees C) and shallow depth. After the tectonic deformation produced by the Brasiliano orogeny, silica dissolution was promoted by high temperature and alkaline hydrothermal solutions rising from the quartzite basement along deep-rooted structures. Hypogene hydrothermal alteration promoted the dissolution of the cherty layers and the precipitation of chalcedony and megaquartz. Homogenization temperatures from primary fluid inclusions in megaquartz cement indicate minimum formation temperatures of 165-210 degrees C. Similar temperature estimates (110-200 degrees C) were obtained from the delta Si-30 and delta O-18 isotope systematics of quartz precipitated from hydrothermal solutions. The dissolved salts in the fluid inclusions were evaluated as NaCl + CaCl2 from microthermometric data combined with cryogenic Raman spectroscopy, corresponding to salinity ranging between 17 and 25 wt.%. No reliable age constraints for hydrothermal silica dissolution-precipitation phases were obtained from monazite U-Th-Pb dating. However, our results, interpreted in the regional context of the Sao Francisco Craton, suggest that the Cambrian tectono-thermal events could have been amongst the possible drivers for this hypogene process in the basin.

The Nirano Salse, known since the Roman Times, are one of the most beautiful and scenic mud volcanoes areas of Italy with thousands of visitors every year. In this work, we apply novel (for the context) hydrogeological techniques to characterize mud levels in the Salse by means of GPS-RTK positioning and continuous level logging within mud conduits. This is important to quantify the gas–liquid ratio in the conduits and evaluate the potential for dangerous abrupt mud eruptions. The results presented suggest that different mud levels in mud volcanoes clusters are due to the different gas–liquid ratio in the conduits and not necessarily exclude interconnection at depth, a hypothesis, on the other hand, that seems strengthened by mud level time series correlations. The presence of shallow aquifers at a depth of 5 to 30 m is also supported by our field data and allows us to delineate the boundaries of the shallow mud reservoir—pipes system and its overall shape. The shallow aquifers may provide a temporary storage for the ascending gas and when fluid pressure in these aquifers exceeds the tensional strength of the sedimentary rock, leakage of fluids to the surface would occur. In this case, if the gas–liquid ratio is high, mud volcanoes develop into tall gryphons and tend to have a discontinuous activity with sudden eruptions of mud after long periods of quiescence. This, together with the knowledge of shallow conduits localization has an important implication for site safety in proximity to the mud volcanoes. Our inferences based on mud level relationships to mud extrusion dynamics can be applied to lower risk in other mud volcanoes areas of the world with high geo-tourist visits, such as those of Trinidad, Azerbaijan, and Colombia.

The low-lying coastal basins of Ravenna (Italy) are at or below mean sea level and currently undergoing land subsidence, which exposes the basins to frequent inundation and groundwater and soil salinization. The surface water drainage becomes necessary to lower the water table head and further prevent flooding and waterlogging. The study examines the evolution of drainage apropos to climate change and land subsidence in the three main Ravenna coastal basins. Our findings show that the evolution of drainage is influenced by land subsidence, climate change variability, droughts, vertical seepage, and local water management. Land subsidence causes an increase in upward-directed vertical seepage of saline water through the shallow unconfined aquifer into the drainage channels of the coastal basins, thus leading to an increase in drainage through time. At a seasonal timescale, the rate of pumping depends on antecedent rainfall and soil–water storage. The warming extremes indices, specifically drought indices, show to be more significant than rainfall indices trends to monitor drainage evolution. Drought indices permit easy comparison of dryness or wetness severity with drainage evolution along their time scale. The co-occurring anthropogenic and natural factors involving in the increasing drainage rate will affect decadal and seasonal water management policies in the area. The implications of increasing drainage rates, long periods of drought with limited rainfall, and increasing temperature will further worsen freshwater availability in this coastal area already experiencing soil and water salinization. However, drainage of this low-lying territory has effectively mitigated rising water tables and avoided flooding. Our study has shown that each coastal basin behaves differently in terms of sensitivity to land subsidence and climate extremes. Therefore, when using drainage data time series for water management purposes, one should account for past management practices and for the specific sensitivity of each basin to external factors.

The coastal aquifers of the Mediterranean region are highly susceptible to seawater intrusion due to a combination of challenges such as land subsidence, high aquifer permeability, urbanization, drainage, and an unsustainable use of water during the dry summer months. The present study is focused on a statistical analysis of groundwater data to evaluate the spatial changes of water level and electrical conductivity in the coastal phreatic aquifer of the Emilia-Romagna (Northeast Italy) for the period from 2009 to 2018. Data from 35 wells distributed across the entire regional coastal area are used to establish a temporal trend, as well as correlations between salinity, water table level, and rainfall. Water table and salinity distribution maps for the entire study area are discussed regarding surface geology and water management. Most of the wells are in the beach wedge sand unit, which allows for easy connectivity between groundwater and surface water. Surface water and groundwater salinization are enhanced along the surface water bodies connected to the sea. The lowest water table level occurs in the western and northern parts of the study area, because of the semiconfined behavior of the aquifer. Only in the northernmost, close to the Po River, and in the southernmost parts of the study area does the groundwater remain fresh for the whole period considered due to river aquifer recharge. In the rest of the region, the thickness of freshwater lenses, where present, is less than 4.5 m. The existence of a water table level below sea level and high saline water at the bottom of the aquifer in most of the study area suggest that the aquifer is in unstable hydrodynamic conditions and groundwater quality is not fit for human consumption or for irrigation. This study is the first to provide a regional overview of the state of groundwater level and salinization within the coastal aquifer of the Emilia-Romagna Region, it also suggests that, overall, the salinization trend has slightly decreased from 2009 to 2018.

Hydrogeochemical analyses were carried out to identify geochemical processes occurring in the low-lying coastal aquifer of Ravenna, North Adriatic Sea (Italy). The area is characterized by a complex coexistence of several environments: coastal dunes, paleodunes, pine forests, freshwater wetlands, rivers, brackish lagoons, gravel pit lakes, reclaimed lands, agricultural fields and industrial areas. Water quality is of primary importance for the sustainability of these, areas and a full understanding of geochemical processing is fundamental for their management. A total of 104 water samples was collected from groundwater wells and surface water bodies, and analyzed for the major and trace elements (TEs). Field measurements of chemical-physical parameters were carried out by a multiparameter device XS PCD650, major elements were analyzed following the Italian National Environmental Agency standards (APAT-IRSA 2003), while TEs were analyzed by ICP-AES/ICP-MS. The major findings include: organic matter degradation in salinized and anoxic conditions, TEs concentrations related to water&ndash, sediment interactions, i.e., adsorption, ion exchange, redox reactions, mineral dissolution and precipitation, anthropogenic contamination from pesticides and fertilizers use, pollution from industrial district, TEs enrichments and depletion due to groundwater salinization and water management practices, comparison of TEs concentrations with respect to national and international thresholds. The findings can provide water managers and local authorities with a comprehensive framework of the coastal water hydrochemistry, allowing a better understanding of the effects of current management practices and the design of mitigation measures to reduce water resource deterioration in the studied coastal area.

The Ridracoli artificial basin is the main water reservoir of the Emilia-Romagna region (Northeast Italy). The reservoir was made by construction of a dam on the Bidente River in 1982. It is used as the main drinking water supply of the region and for hydropower production. The physical and chemical parameterseters (temperature, pH, electrical conductivity, and dissolved oxygen) of shallow water are continuously monitored whereas vertical depth profiles of water chemical data (major anions and cations, as well as heavy metals) are available on a bimonthly base. The dataset used in this research is related to the years 2015 and 2016. Data show that the reservoir is affected by an alternation of water stratification and mixing processes due to seasonal change in water temperature, density, and the reservoir water level. In late summer and winter months, the water column is stratified with anoxic conditions at the bottom. During the spring, on the other hand, when storage is at its maximum, water recirculation and mixing occur. The reservoir is characterized by a dynamic system in which precipitation, dissolution, and adsorption processes at the bottom affect water quality along the reservoir depth column. The temperature stratification and anoxic conditions at the reservoir bottom influence the concentration and mobility of some heavy metals (i.e., Fe and Mn) and, consequently, the quality of water that reaches the treatment and purification plant. This study is relevant for water resource management of the reservoir. Assessing the seasonal changes in water quality along the reservoir water column depth is fundamental to plan water treatment operations and optimize their costs. The reservoir assessment allows one to identify countermeasures to avoid or overcome the high concentrations of heavy metals and the stratification problem (i.e., artificial mixing of the water column, new water intakes at different depths operating at different times of the year, blowers, etc.).

The objective of this study is to explain the occurrence and paleo-stress significance of 3D joint clustering in chert nodules (inclusions) within a layered pelagic limestone sequence. The difference in stiffness between chert and limestone is about one order of magnitude. Field observations show that fracture localization occurs mostly in chert nodules as opposed to the limestone matrix. We show with a novel three-dimensional geomechanical modelling analysis how the inclusion (ellipsoid) axes ratio influences fracture intensity and propagation within and outside the chert nodules and how the nodules record different deformation phases under different remote stress conditions. From field observations, we recognize two joint sets in the chert nodules: joints parallel and normal to the plane containing the two major axes of the nodule (bedding plane). In the nodules, the normal-to-bedding joints are interpreted to be younger than the parallel-to-bedding ones. The modelling of the 3D Eshelby solution for the stress field inside the chert nodule and in the surrounding matrix is consistent with our field observations and it suggests a strong differential stress during deformation (σminr/σmaxr < 0.3). Chert nodules in a deformed carbonate sequence, therefore, can provide important clues on the paleo-stress conditions, the temporal sequence of events, and fracture distribution heterogeneity.