This study evaluates hydrogeochemical characteristics of the hot and mineral waters and traverten waters around the Bolluk Lake in Central Anatolia region (Turkey) which is one of the important geothermal regions for its closeness to the Salt Lake and having unique travertine cones. The study area located approximately 10 km southeast of Cihanbeyli town, 90 km northern of Konya in Central Anatolia. In this context, water chemistry analyses, correlation coefficient calculations of major ions and reservoir temperature calculations were performed.
In the area, Upper Cretaceous Koçyaka formation, ophiolitic melange, containing blocks of different size, forms the basement. Middle Miocene-Lower Pliocene Insuyu formation and Upper Miocene-Pliocene Çataltepe Andesite unconformably overlie the basement. Plio-Quaternary Cihanbeyli and Tuzgölü formations unconformably overlie all these units, and Quaternary travertines unconformably overlie all units. Totally 40 travertine cones were observed in the area, and only eight of them contain water. The total mineralization of hot and mineral waters taking from drill wells and travertine cones range from 2,426.86 mg/l to 5,851.60 mg/l, pH values are in between 6.1 to 8.1, electrical conductivity values range from 3,424 to 6,984 μS/cm and their temperatures range from 20 to 49 °C. On the basis of IAH classification, waters are of “Ca, Mg, Na+K, SO4, HCO3, and Cl type hot and mineralized waters”. The crystalline limestone blocks belonging to the Koçyaka formation, sandstone, conglomerate, and limestone of the Insuyu formation form the reservoir rocks of hot and mineral water. The altered serpentinite and metasandstone of the Koçyaka formation are impervious base properties of the latter units. Also, clay and marls of the Insuyu, Cihanbeyli and Tuzgölü formations form cover rocks. Upper Miocene-Pliocene Çataltepe andesite is considered to be the heat source.