Geochemical and isotopic characteristics of geothermal discharges in the Emet Basin, Western Anatolia, Turkey

The geochemical and isotopic compositions of low-temperature thermal waters in the N-S-oriented Emet Basin, located in Western Anatolia, Turkey, were comprehensively investigated. Three distinct physicochemical processes affecting the chemical composition of the thermal waters were distinguished at this site: dissolution of CaCO3, gradual transformation of Ca-HCO3-type waters to Ca-SO4-type waters by the addition of SO4, and mixing of deep Na-HCO3-type waters with Ca-SO4-type waters. The first two processes are associated with the dissolution of carbonates and evaporites, respectively, and predominantly control the chemistry of thermal waters in the basin. The third process is observed locally and is manifested as CO2-rich thermal waters with relatively higher total ionic concentration.