Isotopic Evaluation of Savcili-Buyukoba (Kirsehir-Kaman) Geothermal Area

Abstract

Isotopic and hydrochemical characteristics of thermal waters in the Savcili-Buyukoba geothermal area are evaluated in this study. Savcili-Buyukoba geothermal area is located in Kaman province of Kirsehir city in Central Anatolia Turkey which is about 150 km southeast of Ankara and 5 km north of Hirfanl? Dam. Measured surface temperatures and specific electrical conductivity values of the thermal waters change between 30.01-34.6ºC and 513-565 ?S/cm, respectively. According to ionic content, the hydrochemical facies of the thermal waters are Na-Cl and cold waters have Ca-HCO3 type. For Savcili-Buyukoba geothermal area, the stable isotope oxygen composition of the water samples ranges from -6.39 ‰ to -12.93 ‰ ?18O-VSMOW and Deuterium ranges from -32.62 ‰ to -94.47 ‰ ?2H-VSMOW. Results of environmental isotopes (?18O and 2H) and hydrochemical analysis show that the thermal waters are meteoric origin. The low tritium (0.18-0.38 TU) content of thermal waters show that the thermal aquifer of Savcili-Buyukoba geothermal area is recharged by groundwater having relatively long residence time which represents a deep groundwater circulation system. Tritium concentrations below 1 TU indicate that groundwater circulation time is at least 60 years.