Lorenza Li Vigni, K.D. (2020). Thermomineral waters of Greece: geochemical characterization. In Abstract Book Conferenza A. Rittmann 12-14 Febbraio 2020.

Thermomineral waters of Greece: geochemical characterization

Lorenza Li Vigni;Kyriaki Daskalopoulou;Sergio Calabrese;Filippo Brugnone;
2020

Many geothermal areas of Greece are located in regions affected by Miocene or Quaternary volcanism and in continental basins characterised by elevated heat flow. Moreover, the majority of them is found along the coast as well as in islands of the Aegean Sea and thus, thermal water is often brackish to saline due to marine intrusion into costal aquifer. In the present study, almost 300 thermal and cold mineral water samples were collected along the Hellenic territory with their physicochemical parameters (temperature, pH, electrical conductivity and Eh) and the amount of bicarbonates (titration with 0.1N HCl) being determined in situ. Additionally, gases, found either in free or dissolved phase, were sampled. Both water and gas samples were analysed at the INGVPa laboratories for major ions (Ion Chromatography), silica (Inductively Coupled Plasma Optical Emission Spectrometry), chemical composition of free and dissolved gases (Gas Chromatography) water isotopes (O and H) and carbon and helium isotopes of free and dissolved gases (Mass Spectrometry). The temperature of the investigated waters ranges from 6.5 to 98°C, pH from 1.96 to 11.98, whilst Total Dissolved Solids (TDS) from 0.06 to 43 g/L. Based on the temperature parameter, waters can be divided into four groups: i) cold (< 23 °C), ii) warm (23 40 °C), iii) thermal (40 75 °C) and iv) hyperthermal (> 75 °C). In terms of pH, most results vary from 5.5 to 8; few springs show either very low pH (< 4) suggesting interaction with H2Srich gases or very high pH values (> 10) proposing serpentinization processes. Regarding TDS concentrations, collected waters can be subdivided into low salinity (up to 1.5 g/L), brackish (up to 20 g/L) and saline (up to 43 g/L). The medium high salinities can be justified by mixing with sea water and/or strong waterrock interaction processes. Isotope composition of O and H ranges from 12.7 to +2.7 ‰ SMOW and from 91 to +12 ‰ SMOW respectively and is generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Only few water samples show a positive shift for δ18O possibly related to high temperature waterrock interaction processes. Carbon dioxide (18 997,000 μmol/mol) or N2 (1100 989,000 μmol/mol) or CH4 (< 0.5 913,000 μmol/mol) are the prevailing gas species found in the studied sites. The δ13CCO2 values ranged from 20.1 to +8.5 ‰, whilst the isotope ratio of He from 0.21 to 6.71 R/RA.
Lorenza Li Vigni, K.D. (2020). Thermomineral waters of Greece: geochemical characterization. In Abstract Book Conferenza A. Rittmann 12-14 Febbraio 2020.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/406509
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