Hydrogeochemical and isotopic composition of a low-temperature geothermal source in northwest Turkey: case study of Kırkgeçit geothermal area

Abstract

Chemical and isotopic compositions of three hot springs and one cold spring in the Kirkgecit geothermal field, located 15 km southwest of Canakkale-Biga in the northwest of Turkey, were monitored five times during 2005 and 2007. The physico-chemical characteristics of the hot springs are average discharge 3–3.5 L/s, surface temperature 45–52 C, pH 8.9–9.3, and electrical conductivity (EC) 620–698 lS/cm. The cold spring has a temperature of 12–13 C, pH 7.5–8.3, and EC 653–675 lS/cm. The hot waters are Na-SO4 type, whereas the cold water is Ca-HCO3 type. Chemical geothermometers suggest that the reservoir temperature is around 80–100 C. The isotopic data (oxygen-18, deuterium and tritium) indicate that the thermal waters are formed by local recharge and deep circulation of meteoric waters.