Hydrochemmical and isotope investigation of Akhüyük (Ereğli – Konya) spring and drilling water

The study covers Akhüyük hot and mineral springs and its surroundings. It is aimed to determine the origin, hydrogeochemical properties, isotopic compositions and reservoir rock temperatures of hot and mineral waters. There are Neogene and Quaternary aged units in the study area and its surroundings. In the study, samples were taken from 13 cold water wells, 3 hot and mineral springs and 3 hot water boreholes. Temperatures of cold waters are 13- 16 oC, pH values are 6.51-7.2, EC values are 289-6050 µS/cm, depths of wells are 84-220, static levels are 8-74 m, dynamic levels are 26-90 m, flow rates are 16-40 l/m. It is between sec. Hot and mineral springs emerged along the fault line on Kükürtlü hill, forming a travertine cone. Source temperatures are between 19oC-21oC, flow rate is 0.1-0.5 l/sec, pH is 6.68 – 7.1, EC values are 5600-10820 µS/cm. Geothermal drilling wells drilled in the resource area have caused some resource outlets to dry out as they reduced the reservoir pressure. The depths of hot water drillings are 800-962 m, the temperature of the water is 21-26.5 oC, pH is 6.9-7.01, and EC values are between 12137-24361 µS/cm. Cold waters are Na-Cl, Ca-HCO3, Na-HCO3 and NaSO4, hot and mineral waters and hot water drilling waters are Na-Cl type waters. Cold waters are not saturated with anhydrite, aragonite, calcite dolomite, gypsum and halite minerals and have the ability to dissolve these minerals. Hot-mineral spring and drilling waters are saturated with aragonite, anhydrite, calcite, dolomite, gypsum minerals and have precipitating properties. Oxygen δ18O values of cold water samples are between-10.43 and 4.37 ‰, δD values are between-26.68 and 67.44‰, δ18O values of hot and mineral waters are between 8.41 and 10.1 ‰, δD values are-11.25. It is between-16.45‰. δ18O and δD values show that the main source of nutrition for its waters is continental precipitation of meteoric origin. High δ3H values, Cl and EC values in hot waters indicate that hot waters have deep circulation, low δ3H values indicate that they are less affected by current precipitation and remain in the aquifer longer than cold waters. High δ3H, low Cl and EC values in cold waters indicate that the waters have shallow circulation, and the high δ3H value indicates that recent precipitation has an effect. According to the δ2H- δ3H relationship, cold waters have a short residence time in the shallow and fast-circulating aquifer, while hot and mineralized waters have a short residence time in the aquifer. It has deep circulation and long residence time in the aquifer. Estimated reservoir rock temperature calculated using geothermometers is between 110-248oC