Hydrochemical and Isotopic Properties of the Mineralized Thermal Waters of Kir§ehir Province, Turkey

The main objective of this study is to determine the chemical and isotopic properties and reservoir temperature of mineralized thermal waters of Kir§ehir region, Turkey. Areas which have been included in this study are Savcih, Karakurt, Terme, Bulamach ,and Mahmutlu.

Mahmutlu and Bulamach waters are mainly of the Na-Cl type, Savcih waters are of the Na-HCOyCl type and Karakurt and Terme waters are mainly of the Ca-HC0₃ type. The saturation index values of the waters have been evaluated and mineralized thermal waters were found to be saturated with respect to the calcite and dolomite minerals but undersaturated with respect to the halite mineral in spite of being NaCl type. The results of hydrochemical and environmental isotope (¹⁸0, D, ³H) analyses show that the waters are of meteoric origin and have varying component of relatively old water. The reservoir temperature of the five areas of thermal manifestations fall between 50 and 100°C. Highest temperatures of about 100°C have been estimated for Bulamach and Mahmutlu using various chalcedony geothermometers. Mahmutlu mineralized thermal water has longer residence times and higher reservoir temperature compared to other geothermal areas in Kir§ehir Province.