Giovanni Vespasiano

Preliminary geochemical and geological characterization of the thermal site of Spezzano Albanese (Calabria, South Italy)

Waters discharging at the Spezzano Albanese spring come from a deep circuit hosted in the Ophiolitic rocks of the Diamante Unit (phyllites and metabasalts, Liberi et al., 2006; Vespasiano et al., 2012b). The unit contains a warm deep aquifer acting as a sort of well-mixed reservoir; during the ascent the waters interact with Tertiary and Quaternary deposits (conglomerates, sands, gypsum and clays with levels of halite) that give them a characteristic composition with near neutral pH value of 7.05 to 7.57, outlet temperatures of 20.16° to 26.6°C, variable redox potentials (–0.25 to 0.28 V) and total dissolved solids from 848 to 9720 ppm.During deep circulation, the waters extract heat from reservoir rocks, attaining thermo-chemical equilibrium and rise relatively quickly to the surface, along sub-vertical faults and fractures, preserving part of their physical and chemical characteristics (Vespasiano et al., 2014).Water chemistry was discussed by means of the triangular diagrams among major anionic/cationic constituents and correlation plots. Triangular diagrams show a Na-Cl composition characterized by high bacterial sulfate reduction. Correlation diagrams attest a high calcite and silica precipitation (likely scaling effect) and show a 1:1 ratio between sodium and chlorine that underline an interaction with halite. This represents only a preliminary study that demonstrates the importance of the geochemical characterization as powerful tool to improve the knowledge of natural environment and to predict and avoid problems linked to the study of thermal sites (Gurrieri et al., 1984; Duchi et al., 1991; Italiano et al., 2010).

Preliminary geochemical characterization of the thermal waters of Caronte SPA springs (Calabria, South Italy)

Literature data with new geological, hydrogeological and geochemical investigations have been used to model the thermal spring waters of Caronte. Waters come from a deep hydrogeological circuit, which is chiefly hosted in the carbonate rocks and evaporites belonging to the Upper Triassic Verbicaro Unit (Iannace et. al., 2007). In particular, the warm deep reservoir has a temperature of ± 45 °C, as indicated by the chalcedony solubility and the SO4–F geothermometers. The warm reservoir is probably located at depths close to 0.9 km, assuming a geothermal gradient of 33 °C km-1. Water leaves the deep reservoir discharges at the surface at 37.3 ± 1.2 °C, with a SO4-Ca composition, after a relatively fast upflow and limited cooling.The upward part of hydrogeological circuit is controlled by local high-angle fault systems as well as by the tectonic window of Sambiase, where the Verbicaro Unit crops out.

Preliminary geochemical characterization of a carbonate aquifer: the case of Pollino massif (Calabria, South Italy)

Groundwater is a very significant water source used for irrigation and drinking purposes in many region, and therefore understanding the hydrogeochemistry of karst water is extremely important. In this study, surface water and groundwater were collected, and major chemical compositions in the water were measured in order to determine the hydro-chemical processes governing the evolution of the groundwater.Water chemistry was discussed by means of the triangular diagrams among major anionic/cationic constituents and correlation plots. Triangular diagrams show that groundwater is typically characterized by Ca–Mg-HCO3 composition in a shallow aquifer, and Ca-SO4 composition in a deeper aquifer. The active geochemical processes in aquifers, with their corresponding time sequence are: dissolution of CO2, dissolution of calcite and dissolution of dolomite.This represents only a preliminary study that demonstrates the importance of the geochemical characterization as powerful tool to improve the knowledge of natural environment.

Hydrogeological and isotopic study of the multi-aquifer system of the Sibari Plain (Calabria, Southern Italy)

Geochemical study allowed to recognize four groups of groundwater for the Sibari Plain (Southern Italy): Ca–HCO3, Na–Cl, Ca–Cl and Na–HCO3. Chloride-rich waters are located close to the Crati mouth that could be a preferential path for seawater ingression. In fact, seawater and brackish waters could move inland along the stream channel and enter the nearby aquifers due to excessive pumping of wells positioned near the river. In alternative, the occurrence of processes, such as ion exchange or dissolution of halite-bearing Miocene evaporite deposits can generate aqueous solutions with similar characteristics to those produced by seawater ingression. Moreover, was calculated the infiltration average (Hi, m a.s.l.) for groundwater of the Sibari Plain by the following equations:The data showed a lower average of the infiltrations in the inner part of the Sibari Plain, with values between 550 and 870 m a.s.l., and higher values (1000/1500 m a.s.l.) moving to NW and SE.

Geochemical modeling as a tool to investigate the release and fate of Cr in the ophiolitic aquifers of Northern Calabria (S-Italy)

The study of the weathering process of ophiolitic rocks represents an important process due the high toxicity of Cr(VI) with environmental and social consequences and health effects.Since this topic is not well understood, a preliminary study on the release of Cr and other constituents during the weathering of the meta-ophiolitic rocks outcropping in Northern Calabria (Fuscaldo zone) has been carried out using the reaction path modeling.In this work, the EQ3/6 software package, version 8.0 was used together with its data0.ymp.R5 thermodynamic database (Apollaro et al., 2013a, b), upon acquisition of the necessary information such as the stability constants of the aqueous complexes of Cr(VI).Preliminary results showed that the geochemical modeling is an important tool to investigate the phenomena which control the redox state of Cr in near-surface environment and the release and fate of Cr and other chemical constituents in these peculiar environments since during the progressive dissolution of the considered lithotypes, the aqueous solution may attain saturation with respect to different secondary solid phases, potentially acting as sinks of various elements and species.

Geochemical and mineralogical characterization of tremolite asbestos contained in the Gimigliano-Mount Reventino Unit (Calabria, south Italy)

In the recent years, many studies have focused on rocks containing naturally occurring asbestos (NOA) with the purpose of determining the potential health risks to exposed neighboring populations. Environmental exposure to NOA has been shown to be a cause of several types of lung disease. The toxicity of asbestos fibres should also depend on the concentration of trace elements and their release in the environment. In this regard the aim of the present work was to characterize four samples of pure tremolite asbestos belonging to Gimigliano-Mount Reventino Unit (Calabria, south Italy). Through a several analytical techniques such as X-ray powder diffraction (XRPD), scanning electron microscopy combined with energy dispersive spectrometry (SEM–EDS), differential scanning calorimetry (DSC), derivative thermogravimetric (DTG) and atomic absorption spectroscopy (AAS), the size, morphology, crystallinity and chemical composition of tremolite samples were discussed to define the impact on the environment and human health.

Preliminary analysis of sediments pollution of the coastal sector between Crotone and Strongoli (Calabria - southern Italy)

This work studies the pollution of the beach sediments along the coastal sector between Crotone and Strongoli towns. 24 samples were investigated through grain size and chemical analyses. The samples are enriched in heavy metals as Ti, Fe, Ni, Co, Ce and V probably related to iron and magnesium minerals. Some samples are characterized by values of As, V, Co and Cr higher than the Italian low limits provided by D. Lgs. 152/2006. These anomalies can be ascribed to a combination of natural causes and anthropogenic activities.

Preliminary geochemical characterization of the thermal waters of the Grotta delle Ninfe near Cerchiara di Calabria (South Italy)

A preliminary geochemical characterization of Cerchiara thermal waters was carried out. Waters discharging at the Cerchiara springs come from a deep circuit, which is chiefly hosted in the limestones, dolomitic limestones and evaporites of the Pollino Unit. Triangular plots of major dissolved cations and anions show that the Cerchiara thermal waters have a mixed Na(Ca)-Cl(HCO3-SO4) composition deriving from extended interaction with carbonate-evaporite rocks. Dissolved sulfate has an Upper Triassic derivation as indicated by sulfur isotopes provided that the effects of bacterial sulfate reduction are properly taken into account. Meteoric waters, infiltrating in the Pollino massif at elevations close to 1800 m asl, recharge the deep aquifer deepening along one or more fault systems, as suggested by local structural geology. They acquire heat from reservoir rocks through conductive transfer during their prolonged circulation into the deep aquifer at temperatures close to 40°C and PCO2 of ~2.5 bar. The thermal deep aquifer acts as a sort of well-mixed reservoir, whose fluids are completely mixed with the fluids entering it. The water leaving the deep reservoir discharges at the surface at 30 °C after a relatively fast upflow and limited cooling. The upward part of the hydrogeological circuit is controlled by local low and high-angle fault systems as well as by the tectonic window of Cerchiara di Calabria, where the Cerchiara Formation crops out.