Hydrogeological and Geothermal Features of Thermal and Mineral Waters of Çamlıdere (Ankara-Turkey)

Abstract

Chemical and isotope compositions of water samples, collected between 2013 and 2014 from 26 springs and wells located in the Çamlıdere region (Ankara, Turkey), were examined. The main objective of the work was to characterize geothermal resources to be exploited in the future. Geothermal springs at Çamlıdere occur in an area of Miocene volcanics consisting of altered andesites, basalts and pyroclastic products. Thermal waters from Çamlıdere area are of Na-HCO3 and Ca-Na-HCO3 type waters with temperatures more than 42°C, while cold waters are mostly of Ca-HCO3 type with low ion content. Geochemical processes responsible for the genesis of the hydrochemical features of the waters include dissolution, mixing, and ion exchange. Reservoir temperatures were estimated and the results indicated that water-rock equilibrium was not attained. The total natural heat discharge is low (less than 1 MWth for all thermal springs and up to approximately 6 MWth for all artesian wells. The estimates indicate a system with limited convective flow. The isotopic data of Çamlıdere water indicates their deep-circulating meteoric origin and allow estimation of infilitration altitude ranging between 1494 and 1833 m a.s.l. The Çamlıdere system is a low-temperature, fracture-zone system that has developed as an advective geothermal system.