Hydrogeochemistry and isotopic study of the travertine deposition of the Tuzlusu (Aksaray) thermal-mineral springs

Tuzlusu thermal-mineral springs emerge at the intersection of faults, parallel to the Tuzgolu fault zone and oblique to these faults in NW of Aksaray. The marbles of the Bozcaldag metamorphics, cropping out at Cal region and its vicinity, form the main aquifer of these springs. The total discharge of the springs is low, while their CO2 and total dissolved solids (TDS) contents are high. In addition to the old travertines extending along the main faultline, recent travertine depositions exist in places where thermal-mineral water appears. The travertine in this region is formed under certain conditions including low flow depth, turbulent flow, and increasing pH and temperature values due to the loss of CO2. Evaluation of 18O, 2H, 3H isotopic data indicates the meteoric origin of the Tuzlusu springs. The temperature of the springs decreases after leaching the granites and evaporites on their circulation paths. The results of 13C analysis show that a part of CO2 of the water is of marine carbonate origin. The hydrochemical facies of the Tuzlusu springwaters are in Na-Ca-Cl-HCO3 and Na-Cl types, and the temperature of the reservoir rock is around 115°C. Total hardness and salinity hazard potential of the springs are high, and hence they could not be used for irrigation purposes