0000000000495272

AUTHOR

Lorenza Li Vigni

Active Degassing of Deeply Sourced Fluids in Central Europe: New Evidences From a Geochemical Study in Serbia

We report on the results of an extensive geochemical survey of fluids released in the Vardar zone (central-western Serbia), a mega-suture zone at the boundary between Eurasia and Africa plates. Thirty-one bubbling gas samples are investigated for their chemical and isotopic compositions (He, C, Ar) and cluster into three distinct groups (CO2-dominated, N2-dominated, and CH4-dominated) based on the dominant gas species. The measured He isotope ratios range from 0.08 to 1.19 Ra (where Ra is the atmospheric ratio), and reveal for the first time the presence of a minor (<20%) but detectable regional mantle-derived component in Serbia. δ13C values range from −20.2‰ to −0.1‰ (versus PDB), with…

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Ludovico Sicardi, an unknown pioneer of the Volcanic Geochemical Monitoring

On December of 1977, almost 100 years since its last eruption, intense volcanic activity took place in Vulcano Island (Sicily). The elevated fluxes and the temperature increase of the fumaroles in La Fossa Crater, as well as the variations in their chemical composition, alarmed the scientific community. During that period, in the city of Palermo, Marcello Carapezza along with his colleagues Mariano Valenza and Mario Nuccio, were studying the fumarolic field of Vulcano. After extended bibliographic research, Valenza discovered the studies of Ludovico Sicardi, which were focused on Vulcano, Stromboli, Vesuvio and Campi Flegrei. Considering the fact that Sicardi’s research was performed 60 yea…

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Preliminary results of carbon degassing in the tectonically active areas of Balkan Peninsula

The deeply derived CO2 from tectonically active areas is contributing in a significant proportion, still unquantified in detail, to CO2 Earth degassing. Several studies highlighted how in these tectonically active areas most of the CO2 is dissolved in the groundwaters circulating in the large regional aquifers hosted by the permeable formations of the active orogens. Quantifying the amount of deep CO2 dissolved into groundwater can represent a powerful tool for regional investigations, because springs are representative of their catchment area that can extend from tens to hundreds of square kilometers. In the framework of a Deep Carbon Observatory supported project, we investigated for the …

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Atmospheric Deposition around the Industrial Areas of Milazzo and Priolo Gargallo (Sicily–Italy)—Part A: Major Ions

The chemical composition of rainwater was studied in two highly-industrialised areas in Sicily (southern Italy), between June 2018 and July 2019. The study areas were characterised by large oil refining plants and other industrial hubs whose processes contribute to the release of large amounts of gaseous species that can affect the chemical composition of atmospheric deposition As in most of the Mediterranean area, rainwater acidity (ranging in the study area between 3.9 and 8.3) was buffered by the dissolution of abundant geogenic carbonate aerosol. In particular, calcium and magnesium cations showed the highest pH-neutralizing factor, with ~92% of the acidity brought by SO42− and NO…

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Chemistry of atmospheric depositions over two polluted industrial areas of Sicily (Italy)

Dry and wet depositions provide the pathways through which particles and gases emitted into the atmosphere return to the Earth’s surface. Bulk deposition is defined as the sum of dry and wet deposition, which is characterized by water-soluble and insoluble chemical species. Recent studies (e.g. Castillo et al., 2017) showed that most of the atmospheric deposition in Europe occurs in the wet form, but in southern European regions the role of dry contribution can be as significant as that of wet deposition. In the framework of the multidisciplinary project “CISAS” (Centro Internazionale di Studi Avanzati su Ambiente, ecosistema e Salute umana), bulk depositions were monthly sampled over two p…

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Degassing and Cycling of Mercury at Nisyros Volcano (Greece)

Nisyros Island (Greece) is an active volcano hosting a high-enthalpy geothermal system. During June 2013, an extensive survey on Hg concentrations in different matrices (fumarolic fluids, atmosphere, soils, and plants) was carried out at the Lakki Plain, an intracaldera area affected by widespread soil and fumarolic degassing. Concentrations of gaseous elemental mercury (GEM), together with H2S and CO2, were simultaneously measured in both the fumarolic emissions and the atmosphere around them. At the same time, 130 samples of top soils and 31 samples of plants (Cistus creticus and salvifolius and Erica arborea and manipuliflora) were collected for Hg analysis. Mercury concentrations in fum…

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Geothermal mercury output at Nisyros Volcano (Greece)

Nisyros (Greece) is an active volcano in the eastern part of the South Aegean Active Volcanic Arc (SAAVA), hosting a high-enthalpy geothermal system. On June 2013, an extensive survey on Hg concentrations in different types of matrices (fumarolic fluids, atmosphere, soils and plants) was carried out at Lakki plain, an area affected by widespread soil degassing and fumarolic manifestations. To investigate the spatial distribution of mercury emission and its possible relationships with diffuse degassing of hydrothermal fluids, Hg concentrations in soils were related to their physicochemical parameters (e.g. temperature, soil-pH, hydrothermal gases and elemental C, N and S concentrations). Fur…

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The CO2 output from the Sperchios Basin area (central Greece): the role of hidden degassing from streams

The Sperchios Basin is an actively spreading rift area with deeply rooted extensional faults and also a site of quaternary volcanic activity. Such geologic conditions favoured the formation of many hydrothermal systems, whose surface expressions are among the biggest thermal springs of the whole Greece. Degassing of deeply derived geogenic CO2 is highlighted by strong bubbling within the main pools of the springs. Flux measurements were made in the Thermopyles spring with the floating chamber method and results showed that bubbling gases in the spring release about 1 ton/day of CO2. The outgoing stream has a flow of more than 250 l/s of water rich in CO2 (about 16 mmol/l). Although no bubbl…

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Signature of the 24th December 2018 eruption of Mt. Etna on the chemical composition of bulk deposition in the Siracusa area (Italy)

Mt. Etna, in the eastern coast of Sicily (Italy), is one of the most active and most intensely monitored volcanoes of the planet. It is widely recognized as a big source of volcanic gases, such as CO2, SO2 and halogens, to the troposphere in the Mediterranean basin, and its gas emissions account for a significant percentage respect to the worldwide average volcanic budget. The SO2 flux from Mt. Etna’s plume has been routinely measured by the INGV since 1987. SO2 flux ranges between 600 to 25000 Mg/d; fluxes greater than 100000 Mg/d were prevalently measured during eruptive events. During eruptive periods, Etna’s emissions can be dispersed over long distances and cover wide areas of the Medi…

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Shallow submarine gas manifestations in the Aegean Sea: preliminary catalogue and geochemical characterization

The Aegean area, like other regions of intense geodynamic activity, is characterised by extensive geogenic degassing. Gas manifestations widespread on land are also very frequent underwater. The present study aims at producing a first catalogue of these manifestations together with the geochemical characterization of the emitted gases. Sixty-one samples at 21 different sites have been collected by diving up to 15 m depth, mainly along the south Aegean active volcanic arc (SAAVA). The sites displayed very different gas fluxes. Most of them showed a very sluggish gas bubbling while a few had spatially large and strong bubbling. The most intense manifestation has been found at Kos Island along…

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Geogenic carbon dioxide degassing from active tectonic areas of the Balkan Peninsula

Sin dagli anni ’70, la ricerca scientifica ha evidenziato una forte relazione tra il degassamento di carbonio profondo e le aree tettonicamente attive, sottolineando l’elevata importanza del contributo di queste emissioni nella quantificazione del carbonio globale. La Penisola Balcanica presenta grandi aree caratterizzate da degassamento di carbonio di origine mantellica, da attività vulcaniche Quaternarie, da un’elevata sismicità e da strutture tettoniche a scala regionale. Purtroppo, la stima del degassamento di anidride carbonica profonda in quest’area è ancora poco studiata. La ricerca di questa tesi di dottorato si è focalizzata sulla (i) stima dell’output di carbonio profondo dalle gr…

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Duvalo (North Macedonia): A "volcano" without volcanic activity

T he Duvalo locality is located in the SW of the Republic of North Macedonia, in the Ohrid region, near the village of Kosel. It is an area of strong soil degassing, called “volcano” by the local people despite volcanic activity has never been documented in the recent geologic history of the area [1]. A large area (thousands of sqm) shows signs of strong alteration and is devoid of vegetation. Until the 19thcentury sulphur was mined from this area [1]. In August 2019, a campaign of soil CO2 flux measurements and soil gas sampling was made. Duvalo is sometimes referred to as an active geothermal feature but no signs of enhanced geothermal gradient were found and the soil temperatures at 50 c…

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Thermomineral waters of Greece: geochemical characterization

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Geogenic carbon transport through karst hydrosystems of Greece

The Earth C-cycle is complex, where endogenic and exogenic sources are interconnected, operating in a multiple spatial and temporal scale (Lee et al., 2019). Non-volcanic CO2 degassing from active tectonic structures is one of the less defined components of this cycle (Frondini et al, 2019). Carbon mass-balance (Chiodini et al., 2000) is a useful tool to quantify the geogenic carbon output from regional karst hydrosystems. This approach has been demonstrated for central Italy and may be valid also for Greece, due to the similar geodynamic settings. Deep degassing in Greece has been ascertained mainly at hydrothermal and volcanic areas, but the impact of geogenic CO2 released by active tecto…

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Monticchio Lakes

The crater lakes are a natural hazard for the population living near them because they can generate liminic explosions, like as the disaster of Nyos lake (Cameroon 1986), in which 1476 people and thousands of animals died. Crater lakes are able to store magmatic and hydrothermal gases and solubilising them into the water. An overpressure of the dissolved gases can generate a limnic eruption. Italy is characterised by an intense volcanic and seismic activity. Evidences of this past volcanism are the numerous crater lakes in Lazio and Campania. The most famous are Bolsena lakes, Vico, Bracciano, Monticchio lakes, Mezzano, Martignano, Albano, Nemi, Averno. The Monticchio lakes (Piccolo Lake (L…

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Gas Geochemistry and Fractionation Processes in Florina Basin, Greece

Florina Basin is located in northern Greece, close to Mount Voras where the volcanic activity of Late Messinian age began. In the area, many CO2-rich gas emissions are present as a bubbling free-phase in groundwater (both springs and wells) and soil gases. Volcanism along with the geological and geodynamic regime of the basin, created the ideal conditions for CO2 accumulation in vertically stacked reservoirs. One of these, industrially exploited by the company Air Liquide Greece, produces 30,000 t/a of CO2. Results show that CO2 concentrations in the gases of Florina can arrive up to 99.8% and are mostly above 90%. Moreover, C-isotope composition (-2.1 to + 0.3 h vs. VPDB) indicates a mixed…

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Fumarolic alteration products of three hydrothermal areas of Greece: Chemical characterization and environmental impact.

Samples of efflorescences and encrustations of hydrothermal origin have been collected at three fumarolic areas in Greece. The three sites are Sousaki, Thiafi (Methana) and Kokkino Nero (Kos) and all belong to the South Aegean Active Volcanic Arc. Samples were analysed for their mineralogical (XRD and SEM-EDS) and chemical composition. Solutions obtained from both mineralization with HNO3 and leaching with distilled water, were analysed for major (ICP-OES), minor and trace metals (ICP-MS) and for sulfate contents (IC). Results show that their composition is mainly controlled by the petrological composition of the substrate (ultramafic rocks at Sousaki, felsic volcanic rocks at Methana and l…

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A christmas gift: Signature of the 24th December 2018 eruption of Mt. Etna on the chemical composition of bulk deposition in eastern sicily

The eruption of Mt. Etna which occurred on December 24th 2018 was characterized by strombolian activity and fire fountains, emitted by the New South-East Crater and along a fissure that propagated towards the SE. The influence of volcanic emissions on atmospheric deposition was clearly detectable at several kilometres from the source. Wet and dry (bulk) deposition samples were collected each month, through a network of eleven collectors, in the areas of Milazzo, and Priolo between June 2018 and June 2019. They were analysed for major ions and trace elements concentrations. The pH values range from 3.9 to 8.3, while the EC values range from 7 to 396 μS cm-1. An extensive neutralization of th…

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Impact of hydrothermal alteration processes on element mobility and potential environmental implications at the Sousaki solfataric field (Corinthia - Greece)

Abstract Samples of efflorescences and encrustations of hydrothermal origin were collected at Sousaki (Greece) and analysed for their mineralogical (XRD) and chemical composition. Solutions obtained both from mineralization with HNO3 and from leaching with deionised water were analysed for major (ICP-OES), minor and trace metals (ICP-MS) and sulfate contents (IC). Results evidence the dependence of the chemical and mineralogical composition on micro-environmental conditions i.e. humidity, oxygen-rich or -poor environment, exposed or sheltered from meteoric agents. In fact, the presence of highly soluble sulfate minerals with elevated contents of many metals (e.g. Mg, Al, Fe, Mn, Cr, Ni, etc…

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Chemical characterisation of the gases released at Gyali Island, Dodecanese, Greece and preliminary estimation of the CO2 output

Greece belongs to the most geodynamically active regions of the world and as such, it has to be considered an area of intense geogenic degassing. In terms of carbon, the territory is characterized by the high hydrothermal and volcanic activity of the South Aegean Active Volcanic Arc (SAAVA), and by widespread geological seeps of buried carbon dioxide and methane. In the present work, we investigate the island of Gyali located in the volcanic system Kos-Gyali-Nisyros. Nine gas samples have been collected on the island of Gyali in areas found both on land, in a small lake (∼2000 m2) along its beach, and in the sea close to the shore at shallow depths (<20 m). Results show that CO2 is the p…

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Degassing at the Volcanic/Geothermal System of Kos (Greece): Geochemical Characterization of the Released Gases and CO2 Output Estimation

Forty-five gas samples have been collected from natural gas manifestations at the island of Kos—the majority of which are found underwater along the southern coast of the island. On land, two anomalous degassing areas have been recognized. These areas are mainly characterized by the lack of vegetation and after long dry periods by the presence of sulfate salt efflorescence. Carbon dioxide is the prevailing gas species (ranging from 88 to 99%), while minor amounts of N2 (up to 7.5%) and CH4 (up to 2.1%) are also present. Significant contents of H2 (up to 0.2%) and H2S (up to 0.3%) are found in the on-land manifestations. Only one of the underwater manifestations is generally rich in N2 (up t…

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Carbon degassing through karst hydrosystems of Greece

Estimation of CO2 degassing from active tectonic structures and regional hydrothermal systems is essential for the quantification of presentday Earth degassing [Frondini et al., 2019 and references therein]. Due to the high solubility of CO2 in water, great amounts of deep inorganic carbon can be dissolved, transported, and released from regional aquifers. By applying a massbalance approach [Chiodini et al., 2000], different sources of the dissolved CO2 can be discriminated. The main source of degassing in Greece is concentrated in hydrothermal and volcanic areas. However, deep CO2 from active tectonic areas has not yet been quantified. A key point of this research is to investigate the pos…

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Characterization of trace elements in thermal and mineral waters of Greece

: Natural thermal and mineral waters are widely distributed along the Hellenic region and are related to the geodynamic regime of the country. The diverse lithological and tectonic settings they are found in reflect the great variability in their chemical and isotopic composition. The current study presents 276 (published and unpublished) trace element water data and discusses the sources and processes affecting the water by taking into consideration the framework of their geographic distribution. The dataset is divided in groups using temperature- and pH-related criteria. Results yield a wide range of concentrations, often related to the solubility properties of the individual elements and…

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Etna International Training School of Geochemistry. Science meets Practice

Also this year, the “Etna International Training School of Geochemistry. Science meets practice” took place at Mt. Etna, now in its fourth edition. The school was hosted in the historical Volcanological Observatory “Pizzi Deneri”, one of the most important sites of the INGV - Osservatorio Etneo for geochemical and geophysical monitoring. Mount Etna, located in eastern Sicily, is the largest active volcano in Europe and one of the most intensely degassing volcanoes of the world [Allard et al., 1991; Gerlach, 1991]. Mt Etna emits about 1.6 % of global H2O fluxes from arc volcanism [Aiuppa et al., 2008] and 10 % of global average volcanic emission of CO2 and SO2 [D’Alessandro et al., 1997; Cal…

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Geochemical characterisation of the alkaline and hyperalkaline groundwater in the Othrys Ophiolite Massif, central Greece

The complex geology of Greece includes two important parallel running ophiolitic belts. The Othrys Massif in central Greece belongs to the westernmost of them. In the current study, 33 water samples from cold hyperalkaline and hypothermal (T < 40°C) alkaline springs and 30 gas samples (either dissolved or free) were collected at 17 different sites in and around this wide ophiolite outcrop, aiming to determine the origin of fluids and evidence gas-water-rock interaction processes taking place in the area. Water samples were analysed for their chemical (major ions and trace elements) and isotope (d18O-H2O, d2H-H2O) composition. They can be subdivided into alkaline (pH <11) of both Mg-Ca…

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The precious treasure of Mariano Valenza: The history of Ludovico Sicardi and the birth of geochemical volcano monitoring

I was lucky enough to meet Mariano Valenza in September 1995. I was hitchhiking on the highway that leads from Cefalu to Palermo to go back home. I had spent my summer holidays in the beautiful and wild Madonie mountains. An off-road vehicle (a Land Rover Defender) stopped and a refined gentleman with a curious and charismatic gaze offered me a ride. During our journey, we chatted pleasantly and he told he was originally from that area. When I told him, I was a Geology student, he smiled at me and said Then we will meet again soon, I am going to be your Teacher of Geochemistry!. After a few weeks the lessons began and I met again Professor Valenza in Via Archirafi 36, at the University of P…

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Preliminary geochemical characterization of gas manifestations in North Macedonia

<p>Like most of the Balkan Peninsula, North Macedonia is a geodynamically active area. As such it has many hydrothermal features and gas manifestations. Until now, no systematic study about the geochemical characterization of the geogenic gases was made before in this country. In August 2019, 24 gas samples were collected in the study area. All, except one collected at Duvalo (soil gas), are gases bubbling or dissolved in thermomineral waters (temperatures from 12 to 66 °C). They were analysed in the laboratory for their chemical (He, Ne, Ar, O<sub>2</sub> , N<sub>2</sub> , H<sub>2</sub&…

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Geochemical characterization of trace elements in thermomineral waters of Greece

Trace elements have a fundamental role in natural and anthropogenic systems. In waters, they present a great variability of concentrations that mostly depends on the degree of gaswaterrock interactions and geochemical conditions such as pH, temperature, redox and/or exchange reactions, etc. Even though, they are present in very low contents in hostrocks, elevated concentrations in ground or surface waters may have a hazardous impact on human and animal health and thus, it is important to both quantify and try to understand their behaviour in natural systems. Here we present the results of about 300 cold and thermal mineral waters collected along the entire Hellenic territory. Physicochemica…

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Determinazione in continuo di CO2, CH4 e H2Ov in ambiente atmosferico attraverso tecnica ad assorbimento laser (UGGA)

Molti dei composti chimici presenti nell’atmosfera terrestre prendono il nome di “gas serra”. Queste specie gassose consentono alla radiazione solare di entrare liberamente nell’atmosfera e di trattenere parte della radiazione solare riflessa dalla superficie terrestre come energia termica. Nel corso del tempo si instaura un complesso equilibrio termico tra la quantità di energia inviata dal sole e quella irradiata dalla superficie. L’alterazione di questo equilibrio, con l’aumento di uno o più gas serra in atmosfera, porta a degli squilibri termici e un conseguente innalzamento delle temperature. Questo fenomeno è definito come “effetto serra”. I principali gas serra in natura che prendono…

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Atmospheric Deposition around the Industrial Areas of Milazzo and Priolo Gargallo (Sicily–Italy)—Part B: Trace Elements

The concentrations of trace elements in atmospheric bulk depositions (wet plus dry) were investigated from two highly industrialised areas of Sicily (southern Italy) from June 2018 to July 2019, in order to recognise the main natural and anthropogenic sources. A side objective of this study was to improve the common sampling procedures and analytical methods used for monitoring trace elements in atmospheric deposition. The trace element VWM (Volume-Weighted Mean) concentrations ranged from less than 0.01 μg L−1 for trace elements such as Cs, Tl, and U, up to 24 μg L−1 for minor elements (Al, Zn, Sr), in the filtered aliquot, while they reached concentrations up to 144 μ…

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Geochemical characterisation of the thermo-mineral waters of Greece

AbstractGeothermal areas of Greece are located in regions affected by recent volcanism and in continental basins characterised by elevated heat flow. Many of them are found along the coast, and thus, water is often saline due to marine intrusion. In the current study, we present about 300 unpublished and literature data from thermal and cold mineral waters collected along Greece. Samples were analysed for major ions, Li, SiO2 and isotopes in water. Measured temperatures range from 6.5 to 98 °C, pH from 1.96 to 11.98, while Total Dissolved Solutes (TDS) from 0.22 to 51 g/L. Waters were subdivided into four main groups: (1) thermal; (2) cold; (3) acidic (pH < 5); and (4) hyperalkaline (pH …

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Chemical-physical parameters, major, minor and trace elements composition of thermo-mineral groundwaters of Greece

This dataset comprises samples of thermo-mineral waters collected by the same team over the period from October 2004 to March 2020 and analysed in the same laboratory. Samples were collected on the whole territory of Greece.

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Chemical-physical parameters, major, minor and trace elements compositions of big karst springs of Greece

This database consists of samples of karst springs collected in Greece and selected on the base of their water flow (> 50 L s-1), over the period from May 2016 to October 2022

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