Chemical And Isotopic Characterization Of The Thermal Fluids In The South-western Margin of the Loutros-Feres-Soufli Tertiary Basin in Northern Greece. Case Study: Geothermal Area of Aristino

In this work we examine the hydrochemical and isotopic characteristics of the thermal fluids in the Aristino geothermal area in the southwestern margin of the Loutros-Feres-Soufli Tertiary basin (LFS), which is located west of Evros river in Northeastern Greece, in order to identify their possible origin and the expected procedures responsible for the alteration of the initial composition of them. The studied fluids are characterized by high Cl¯ and Br¯ contents, which indicate a higher or lower marine contribution. Furthermore, the elevated B and Li+ values and the low Mg2+ values respectively, are related to high temperatures indicative of water-rock interaction procedures. Additionally, we observe an enrichment of δ18O values, which is another indicator of water-rock interaction that occurs in areas with high thermal potential. Finally, we attempt to evaluate the deep reservoir temperatures with the application geothermometers. Their values reflect an equilibrium process with the probable existence of a deep hydrothermal system of middle to high enthalpy.