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 have been collected at Sousaki (Greece) and were 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.) further underscores the important influence of hydrothermal activity on elements' mobility, whilst the sometimes very high concentrations in toxic elements like Al, Cr, Ni evidence also possible environmental impacts.

Characterization of trace elements in thermal and mineral waters of Greece

“…Moreover, the geo-tectonic setting and the presence of SAAVA also had an impact on the chemical characteristics of the waters. For instance, geothermal activity in Sousaki (central Greece) has resulted in alteration outcrops rich in highly soluble sulfate minerals with enhanced trace metal content (D’Alessandro et al 2020 ), while the volcanism and the fault system of Milos Island are responsible for the metalliferous mineralization (Fytikas 1977 ; Kilias et al 2001 ). Further mineral deposits in Greece are connected to recent (Miocene–Pliocene) volcanism (Melfos and Voudouris 2012 ; Pe-Piper et al 2014 ; Skarpelis 2002 ).…”

“…Even though abnormal trace element levels often reflect anthropogenic factors, harmful trace element levels may also derive from natural processes (contamination) (e.g. Brugnone et al 2020 ; Calabrese et al 2016 ; D’Alessandro et al 2017 ; 2020 ; Gagliano et al 2019 ; Rognerud and Fjeld 2001 ). For example, volcanic activity is a strong contributor of trace elements to the atmosphere (Calabrese et al 2011 ; Liotta et al 2021 ) and the ocean (Elderfield and Shultz 1996 ).…”

Shallow Sea Gas Manifestations in the Aegean Sea (Greece) as Natural Analogs to Study Ocean Acidification: First Catalog and Geochemical Characterization

“…It is important to note that this is a preliminary catalog of shallow submarine vents found in the Aegean Sea. Springs found in tectonic structures on-land close to the coast (Li Vigni et al, 2021) characterized by strong degassing (Daskalopoulou et al, 2019a) and soil alterations (D'Alessandro et al, 2020) can be good indications of nearby submarine degassing underscoring that the catalog has still to be completed. Nevertheless, we aim that this study will initiate further research on the OA in Greece and in other countries.…”