Hydrogeology of ilicabaşi geothermal field (Aydin)

Some lithological units,ranging from Paleozoic to Quaternary age, crop out in the water reservoir. These are overlain by these rocks are gneisses, schists, metaquartzites and marbles. These rocks are covered with Neogene aged sedimentary rocks, pebble stones, sandstones, claystones, by an unconformable contact. The study area plain cover completely by Quaternary Alluvium.Analyses of waters sampled of study area and some of data from deep wells drilled by MTA in Aydın-Ilıcabaşı geothermal fields were used for this study to evaluate the physical and chemical propaties of geothermal fluids. The water temperatures of hot springs vary between 34 ? 440C. Electrical conductivity values for thermal springs were in between 3000 ?mho/cm and 1771 ?mho/cm for hot waters of deep well. Electrical conductivity values of cold groundwaters were about 1281 ? 1639 ?mho/cm. pH values of hot and cold waters are between 6.09 ? 6.76 and 6.38 ? 7.58, respectively.According to doing hydrogeochemical estimates, hot waters are the origin of Na-HCO3-SO4 and Ca- Na- MgSO4-HCO3 , most of cold groundwaters are Ca-Mg-SO4-HCO3 .The Enthalpy ? Silica mixing model is based on heat and silica balance and used to evaluate the mixing ratio of cold and hot water components of mixed waters and the reservoir temperatures. The reservoir temperatures were found between 230-2700C. According to the result of SiO2 geothermometres, the reservoir temperatures are 40-120oC.