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The geochemical characteristics of fluids that emerge at the Earth's surface are influenced by gas-rock-water interactions in the deep and shallow crustal layers, including mixing, outgassing of volatiles, and precipitation of minerals. The goal of the study was to understand the various interactions that influence the migration and behaviour of fluids within the Earth's crust and how they may change during the process of crustal fluid migration towards a hydrothermal system in the shallow crustal layers and within (Contursi basin, Italy). These processes can make it difficult to identify the source of deep gas by using the classical approach based on mixing processes of fluids and carbonate dissolution. Therefore, alternately the relationship between Total Dissolved Inorganic Carbon (TDIC) and the δ13CTDIC in groundwater from the Contursi hydrothermal system investigating the water-gas-rock interaction at the local scale through the detailed reconstructions of the geological framework at depth have been taken into consideration. We found that both the dissolved and free gas in the hydrothermal system probably originated from a deep CO2 endmember with a δ13CCO2 value ranging from +2.12‰ to +3.20‰ (PDB) depending on the presence of brine or freshwater in the local aquifers. However, we observed that this CO2 lost its pristine carbon isotopic signature during its storage in the deep dolomite-composed reservoirs (6-8 km), making it challenging to figure out its deep origin (decarbonation vs mantle/magmatic CO2). Our calculations also showed that the output of CO2, taking into account secondary processes (i.e. degassing CO2 and calcite precipitation) and interactions with water at different salt concentrations, could be at least 40% higher than estimates from the mixing-only approach, such that it is comparable with several active and quiescent worldwide volcanic systems. In order to interpret potential geochemical changes that may occur during future seismic events in sites like Contursi, which are earthquake-prone areas, it is necessary to implement models that can help us understand fluids origin and the processes that influence their chemical and isotopic signature.

The southern Apennines are affected by great crustal deformation and tectonic activity, where fluids from different reservoirs mix and rise to the surface through fault structures. Tramutola well (TRW) is an old borehole built by ENI, with the occurrence of bubbling gases located in the High Agri Valley (HAV), Southern Italy. The HAV is an inter-montane basin of the southern Apennine chain characterized by complex geological setting and high seismicity, this area hosts also the largest onshore Western European oil field. TRW is about 400 m deep it crosses clays, silicic clays and silicic limestone and is characterized by the continuous emission of thermal water (28°C) and bubbling gas. The water belong to Na-HCO3 hydrofacies. TRW gases are CH4-dominated (82,6 %), and low amounts of N2 (12,9%), CO2 (1,7%), C2H6 (0,3%). The noble gases are used to discriminate the fluids origin (atmospheric, crustal and mantle). The 4He/20Ne ratio values are in three orders of magnitude higher that air-one (0,318) and 40Ar/36Ar ratio it is about 320 (Air=295.5; Hilton and Porcelli, 2003), this confirm the atmospheric contribution is present. Value Helium isotope (3He/4He, expressed as R/Ra) is between 1,13 and 1,26 Ra, and indicate a radiogenic component with a contribution of a mantle-derived helium (~20%). Methane isotope composition indicates a likely microbial isotopic signature (δ13C-CH4 =-63‰, δD-CH4= −217‰), probably due to either (1) biodegradation processes of thermogenic hydrocarbons or (2) ongoing microbial methanogenesis in the shallow organic‐rich clays hosting the gas. The δ13C-CO2 value between of -3.5‰ and -6‰ VPDB, consistent with a mantle origin. The gases have low CO2/3He ratios compared to mantle carbon end-member, probably due to secondary processes such as calcite precipitation. In conclusion, at Tramutola well have three gas sources and their possible mixing processes: (1) Shallow source, highlighted by atmospheric gas and rainwater entering the system through water infliltration; (2) crustal sources, CH4-dominant gas sources in correspondence of the hydrocarbon reservoir; (3) SCLM mantle source, mantle-derived fluids uprising through lithospheric normal faults.

Mount Vulture is a stratovolcano (age 0.75-0.14 Myr) located in southern Italy, which despite being at the same latitude of Vesuvius and Phlegreian Fields, has several peculiarities about its setting and erupted magma composition. Indeed, if compared to other Italian Quaternary volcanoes, it is the only one located east of the Apennine Front, about 100 km off the axis of the Campanian Magmatic Province (Peccerillo et al., 2017). Furthermore, although being a quiescent volcano (last eruption dated 0.14 Myr), previous studies (e.g., Caracausi et al., 2015, Bragagni et al., 2022) have shown extremely high CO2 emissions (4.85 × 108 mol yr-1), which are likely related to the carbonatitic volcanism of its final phase of activity, as well as some petrological aspects in the erupted products pointing to a mantle source metasomatism.Recently, investigations on Vulture mantle xenoliths (Carnervale et al., 2022) revealed CO2-rich fluid inclusions (FIs) that indicate a primary depth of bubbles entrapment in olivine and pyroxene phenocrysts coinciding with the regional crust-mantle boundary (27-30km).This research focuses for the first-time noble gases isotopes (He, Ne, Ar) in FIs from lherzolite enclaves from Mt. Vulture tephra. The He isotopic ratios (as R/Ra; R is the 3He/4He ratio of the sample and Ra the same ratio in air), are between 6.2 and 5.4 ± 0.08. These values are lower than the signatures of the MORB upper mantle (8 ± 1Ra) and overlap the values of the Sub Continental Lithospheric Mantle (SCLM, 6.1 ± 0.9Ra). The Ne isotopic signatures (20Ne/22Ne and 21Ne/22Ne) are in the field of the MORB values.The He-Ne-Ar systematics is consistent with a SCLM source feeding the magmatism of the Vulture volcano. However, considering the noble gases He-Ne-Ar, in Vulture xenolites this mantle source has affinities with that feeding the volcanic activities of Mt. Etna (Nakai et al., 1997; Correale et al., 2014). This inference bears some evidence about the similitudes of the mantle below these two volcanic systems that is affected by mantle metasomatism, which is likely also responsible for the large CO2 fluxes and the carbonatitic magmatism (Bragagni et al., 2022). New measurements of the noble gases in free gases from the two volcanoes together with a detailed comparison between the geochemistry and petrography of the Vulture and Etna most primitive products will provide new constraints on the mantle typology below the two volcanoes and its relationship with the geodynamical evolution of the central Mediterranean.References Bragagni et al., 2021, GeologyCarnevale et al. (2022). Geophys. Res. Lett.Caracausi et al. (2015). Earth Planet. Sci Lett.Correale et al., 2014. LithosNakai et al., (1997). Earth Planet. Sci Lett.Peccerillo, A. (2017). Advances in Volcanology. Springer, Cham.

In the Pollino Massif, in the southern Apennines, the asbestos minerals bearing serpentinites are widely exposed at several quarries (Pietrapica quarry, Timpa Castello quarry, Fagosa quarry and Ghiaia quarry), whose material was extracted and used as aggregates for construction, filling and embankments, and as ornamental stones. Airborne asbestos can be the result of extraction procedure as the stacking, storing and grinding of the serpentinites, so due to the environmental concerns the quarries have been abandoned. In the Pollino Massif serpentinites represent the lherzolitic to harzburgitic upper mantle basament of the Internal Liguride sequence of southern Apennines and can be classified as cataclastic and massive (Dichicco et al., 2015). Cataclastic serpentinites are fractured and deformed whereas those massive show a low fracturing and deformation. The serpentinites have homogeneous mineral compositions and are mainly composed by serpentine polimorphous, asbestiform tremolite, followed by actinolite, chlorite, magnetite and Cr-spinels, and subordinatly calcite, dolomite, and clay minerals. Further, edenite, currently not regulated by the Directive 2003/18/EC of the European Parliament and of the European Council of 27th March 2003, has been recently also detected for the first time (Dichicco et al., 2019). Serpentinite rocks can release significant amounts of fibers of hazardous minerals for the human health, into the air, water and soil, either through geogenic weathering processes or human activity. The observed fibers in the outcrops are of two types: 1) large and elongated fibers that occupy the entire surface of the rock; 2) tiny fibers forming a network throughout the rock.The aim of this work is to characterize in a detailed way the asbestos minerals of representative serpentinite samples taken from the four quarries using the combination of different analytical techniques: field surveys, X-Ray powder diffraction (XRPD), scanning electron microscopy combined with energy dispersive spectrometry (SEM/EDS), µ-Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR) in order to assess the impact on the environment and public health.References:Dichicco, M.C.; Laurita, S.; Paternoster, M.; Rizzo, G.; Sinisi, R.; Mongelli, G. Serpentinite Carbonation for CO2. Sequestration in the Southern Apennines: Preliminary Study. Energy Procedia 2015, 76, 477-486.Dichicco, M.C.; Paternoster, M.; Rizzo, G.; Sinisi, R. Mineralogical Asbestos Assessment in the Southern Apennines (Italy): A Review. Fibers 2019, 7, 24.

Asbestiform minerals are potentially toxic and harmful to health and the environment and, in recent years, several studies have been made on the presence of asbestiform minerals in the Pollino Massif, on the border between Lucania and Calabria regions (southern Italy). Moreover, these small fibers can be easily inhaled by humans causing serious health problems especially to the respiratory tract. The formation of asbestiform minerals is related to metamorphism and/or metasomatic alteration of the metamorphic rocks. The main asbestiform mineral phases which have been found in the Pollino Massif are tremolite and, for the first time, edenite and Magnesium-riebeckite. The observed asbestiform minerals found in the metamorphic rocks of the Pollino Massif are thus: i) tremolite, which is characterized by acicular, friable, fibrous, and elongated habitus and was found as intergrowth with fibrous antigorite and chrysotile. In the analyzed rocks, tremolite was found in veins associated with clinopyroxene porphyroclasts; ii) edenite, which is often associated with serpentine, diopside and calcite or occurs as 30 to 80 µm-long single crystals with a fibrous habit. The presence of edenite in the ophiolitic sequences is quite rare and testifies a medium to high metamorphism; iii) magnesium-riebeckite, a record of metamorphic events in blueschist facies, composed of prismatic, acicular crystals with a fibrous habit having length ≥ 5 µm and width < 3 µm with aspect ratio > 3:1. These mineralogical phases were analyzed and characterized using different analytical techniques such as X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), electron probe micro analysis (EPMA) and X Ray Powder diffraction analysis (XRPD). The aim of this work is to create, for the first time, a geo-mineralogical map of the asbestiform minerals detected in these areas in order to evaluate their spatial distribution.References:Dichicco, M.C.; Laurita, S.; Sinisi, R.; Battiloro, R.; Rizzo, G. Environmental and Health: The Importance of Tremolite Occurence in the Pollino Geopark (Southern Italy). Geosciences 2018, 8, 98.Dichicco, M.C.; Paternoster, M.; Rizzo, G.; Sinisi, R. Mineralogical Asbestos Assessment in the Southern Apennines (Italy): A Review. Fibers 2019, 7, 24.Laurita, S.; Rizzo, G. The First Occurrence of Asbestiform Magnesio-Riebeckite in Schists in the Frido Unit (Pollino Unesco Global Geopark, Southern Italy). Fibers 2019, 7, 79.

In seismic active areas, the primary composition of natural gas emissions can be modified upon migration to the surface and storage in crustal reservoirs as the result of secondary chemical processes at shallow levels that can change the pristine composition of the fluids creating misunderstanding in the evaluation of the contributions due to different sources. Noble gases are among the most powerful indicators of such natural processes. In particular, Helium (hereafter He) is a reliable geochemical tracer for discriminating the crustal and mantle components in the outgassing gases due to the different origin of its two isotopes (3He has a primordial origin, whereas 4He is continuously produced by radioactive α-decay of 235,238U and 232Th). Therefore, the 3He/4He ratio is considered one of the most efficient geochemical tracers, whose variations can be directly ascribed to magmatic/crustal dynamics and therefore it is of primary importance in volcanic and seismic forecasting. In this study, we report chemical and isotopic (helium and carbon) data of gases and water emitted from three areas characterized by a high seismic hazard and located within the southern Apennines seismogenic belt. Through two fieldwork campaigns in 2019-2020, about 15 sites were inspected. Carbon dioxide is the main component in most of investigated sites (> 90 vol.%), except for Pozzo Tramutola, that is CH4-dominated. He and N2 concentrations are significantly variable (from 6 to 260 ppm and from 0.22 to 12.78 vol%, respectively). In agreement to previous investigations (Italiano et al., 2001; Caracausi and Paternoster, 2015), the sites in the Matese area are characterised by typical metamorphic [MOU1] N2 values and low content of He and Ar and seem to be the result of mixing processes between crustal and/or metamorphic and atmospheric or ASW end-member. The sampled fluids have 3He/4He ratios from 0.02 to 2.92 Ra with corresponding He/Ne ratios in the range of 0.353-508.10. These 4He/20Ne ratios are much higher than the same ratio in the atmosphere (He/Ne=0.318; Ozima-Podosek, 2002) supporting that atmospheric He component in the sampled fluids is negligible for most sites. In general, we recognized that 3He/4He ratios indicate mixing between radiogenic and mantle end-members and Mefite site has highest mantle values that are close to the ratio at Mt Vesuvio and Pleghreian volcanic systems (< 60 from the study area). The 40Ar/36Ar ratios show a small range from values close to atmosphere up to 40Ar/36Ar = 325. We also investigated the carbon species and their isotopes. To investigate the genetic origins of the methane we have used web-based machine learning tool that determines the origin of natural gases (Snodgrass-Milkov, 2020) and the results shown that methane is mainly thermogenic even if we also recognized an abiotic component in a few of sites. This study will provide data for the reconstruction of a basic model for interpreting the relationships between outgassing and tectonics, and further for interpreting possible seismic-induced variationOzima & Podosek. 2002. Noble Gas Geochemistry.Tsunogai & Wakita. 1995. ScienceSnodgrass and Milkov, 2020. Comput. Geosci

The Pietra del Pertusillo fresh-water reservoir is located in the High Agri Valley (Basilicata region, Southern Italy). The present work represents a first comprehensive study about the mineralogy and the geochemistry of fluvial-lacustrine sediments and bedrock lithologies of this fresh-water reservoir catchment area. Lacustrine (15 samples), fluvial-lacustrine (14 samples) and local bedrock sediments (27 samples) have been sampled and mineralogical and geochemical analyses have been performed on the sampled sediments. The mineralogical assemblage is mainly composed of quartz and calcite and minor feldspars, muscovite, illite, chlorite, and interstratified clay minerals. The geochemistry reveals that major oxides are SiO2, Fe2O3, Al2O3, and CaO. Attention has been paid to the presence of potentially toxic chemical elements (heavy metals) within the sampled sediments. The heavy metals are mainly enriched in the fine fraction of lacustrine sediments since they are mostly absorbed in the clay fraction (Geochemistry of fluvial-lacustrine and bedrock sediments revealed that, in some cases, several heavy metal elements like Cr, Co, Ni, Zn, As, Ni and Pb exceed some regulatory limits concerning their distribution in lake sediments. It should be noted that, in Italian legislation, there are no regulations concerning limit concentrations of heavy metals in fluvial and fluvio-lacustrine sediments and therefore, for lacustrine sediments, values related to aquatic environments are taken into account. The considered regulatory are the Canadian ISQG (Interim Freshwater Sediments Quality Guidelines) and the Italian D.M. 367/03 (Regulation on the setting of quality standards in the aquatic environment for dangerous substances).Furthermore, enrichment factors (EFs) for heavy metals were calculated, assuming Ti as an immobile element, both with respect to UCC (Upper Continental Crust) and local bedrock composition. Local bedrock composition was calculated based on the average composition and weighted on the areal extension of the outcropping bedrock lithologies. Enrichment factors showed that heavy metals like Pb, Zn, and Co, in relation both on UCC and local bedrock, showed values of EFs >2, which corresponds to a moderate enrichment. Other heavy metals, in particular Cu and As, showed EFs >5, which corresponds to a significant enrichment.This work aims to get a clear picture of the causes which control and influence heavy metals concentration as well as their distribution within sampled sediments. Finally, it would be appropriate to establish worldwide quality standards on all pollutants in different natural environments in order to obtain a homogeneous reference for all countries.References:Giocoli, A. , Stabile, T. A., Adurno, I., Perrone, A., Gallipoli, M. R., Gueguen, E., Norelli, E., Piscitelli, S., 2015. Geological and geophysical characterization of the southeastern side of the High Agri Valley (southern Apennines, Italy), Nat. Hazards Earth Syst. Sci. 15, 315-323.McLennan, S.M., Taylor, S.R., Hemming, S.R., 2006. Compostion differentiation and evolution of continental crust: constraints from sedimentary rocks and heat flow. In: Brown, M Rushmere T (eds) Evolution and differentiation of continental crust. Cambridge p 377.Reimann, C., De Caritat, P., 2005. Distinguishing between natural and anthropogenic sources for elements in the environment: regional geochemical surveys versus enrichment factors, Science of the Total Environment 337(1-3), 91-107.

The Latronico thermal area is located in the southern sector of the Apennines chains, in proximity to the south boundary of the Mt. Alpi. This area is a seismically active region and it is located between Val d’Agri basin and Pollino area, two of the highest seismic risk zones in Italy. It is well documented that tectonic discontinuities act as preferential channels for the uprise of deep fluids trough the continental crust towards the surface (e.g., Caracausi et al. 2013). Hence in seismically areas, these fluids can move across the volume of rocks characterized by an active field of stress and their fluids can take a memory of the occurring rock-water-gas interactions. Taking this into account, we sampled waters and dissolved gases released in the Latronico hydrothermal basin in order to define: i) water-rock interaction processes; ii) thermalism origin; iii) the geochemical model of fluid circulation in a seismic area. In details, we analysed the chemical and isotopic (C and noble gases) composition both groundwater and dissolved gases. The acquired knowledge will allow us to plan long-term geochemical monitoring useful for identification of the possible relationship between fluid circulation and regional-scale seismicity. We sampled 24 springs, of which 9 belonging to thermal set (Latronico Spa springs) and 15 to cold one. Thermal waters have an average temperature of 21°C, these are slightly alkaline (7.12 2 and He contents of 1 and 2 order of magnitude higher than cold water, respectively. The dissolved gases show an atmospheric component, being Air Saturated Water (ASW). 3He/4He ratios in the gases dissolved are 0.12 Ra ±0.2 (Ra is the He isotopic signature in the atmosphere, 1.39x10-6). Assuming that He isotopic signature in typical crustal fluids is < 0.05 Ra, the measured He data show traces of mantle-derived helium, to the mixing between atmospheric and radiogenic end-members (0.02 Ra). Coupling Total Dissolved Inorganic Carbon (TDIC) and δ13CTDIC data, 2 water sub-sets have been identified: (i) infiltrating waters, with low δ13CTDIC, and (ii) thermal waters with positive δ13CTDIC and high TDIC values, indicative of outgassing of deeply sourced CO2. This study for the first time proposes a model of fluids origin in the Latronico hydrothermal basin and the main processes that control their chemistry during their circulation through the crust. Hence, geochemical monitoring of the fluids in the region can provide if these fluids are sensitive to chemical variation due to a modification of the field of stress in the preparatory phases of an earthquake

Throughout the Mediterranean, salinization threatens water quality, especially in coastal areas. This salinization is the result of concomitant processes related to both seawater intrusion and water–rock interaction, which in some cases are virtually indistinguishable. In the Nurra region of northwestern Sardinia, recent salinization related to marine water intrusion has been caused by aquifer exploitation. However, the geology of this region records a long history from the Palaeozoic to the Quaternary, and is structurally complex and comprises a wide variety of lithologies, including Triassic evaporites. Determining the origin of the saline component of the Jurassic and Triassic aquifers in the Nurra region may provide a useful and more general model for salinization processes in the Mediterranean area, where the occurrence of evaporitic rocks in coastal aquifers is a common feature. In addition, due to intensive human activity and recent climatic change, the Nurra has become vulnerable to desertification and, in common with other Mediterranean islands, surface water resources periodically suffer from severe shortages. With this in mind, we report new data regarding brackish and surface waters (outcrop and lake samples) of the Na-Cl type from the Nurra region, including major ions and selected trace elements (B, Br, I, and Sr), in addition to isotopic data including δ18O, δD in water, and δ34S and δ18O in dissolved SO4. To identify the origin of the salinity more precisely, we also analysed the mineralogical and isotopic composition of Triassic evaporites. The brackish waters have Cl contents of up to 2025 mg L−1 , and the ratios between dissolved ions and Cl, with the exception of the Br / Cl ratio, are not those expected on the basis of simple mixing between rainwater and seawater. The δ18O and δD data indicate that most of the waters fall between the regional meteoric water line and the global meteoric water line, supporting the conclusion that they are meteoric in origin. A significant consequence of the meteoric origin of the Na-Cl-type water studied here is that the Br / Cl ratio, extensively used to assess the origin of salinity in fresh water, should be used with care in carbonate aquifers that are near the coast. Overall, δ34S and δ18O levels in dissolved SO4 suggest that water–rock interaction is responsible for the Na-Cl brackish composition of the water hosted by the Jurassic and Triassic aquifers of the Nurra, and this is consistent with the geology and lithological features of the study area. Evaporite dissolution may also explain the high Cl content, as halite was detected within the gypsum deposits. Finally, these Na-Cl brackish waters are undersaturated with respect to the more soluble salts, implying that in a climate evolving toward semi-arid conditions, the salinization process could intensify dramatically in the near future.