Hydrogeochemical and hydrogeologic investigation of the Germencik- İncirliova(Aydın) geothermal fields

This study contains hydrogeocial, hydrogeochemical and isotopic investigations in the Germencik- İncirliova geothermal fields which are one of the most important geothermal fields of Turkey.Aydın-Germencik-Incirliova geothermal region continues along east-west direction line and locates in the west side of Menderes rocks. There is an expansion in north-sorth direction because of the tectonic stress, and there is a graben in east-west direction at the result of the continues rise in Menderes Massif rocks, it also developed a step fault system.First reservoirs of the geothermal system is made up of the fractured gneiss with quartz schists, karstic marbles and in some areas Neogene conglomerates of the Menderes Massif rocks. Neogene aged claystone and mudstone, also have cap rock characteristic. Hydrogeologic, hydrochemical and isotopic studies shows that geothermal waters in region have high enthalpy, may also be meteoric origin with a little magmatic ingredient, and old water (which hardly have any tritium isotopes so they are at least 50 years old). Meteoric waters recharge the reservoir rock and are heated at depth and move up to the surface through the tectonic lines by convection currents. Twelve water points were sampled periodically during the one year the determine the hydrogeochemical evaluation of geothermal waters and hydrodynamics of groundwaters for the study area. The geochemical experiments have been done with the hot-cold water which collected from study area, anion, cation and trace elements of the water have been identified. According to doing hydrogeochemical estimates, hot waters are the origin of Na-K-CI-HCO3 and Na-K-HCO3, most of cold groundwaters are Na-Ca-CI-HCO3, Mg-Na-Ca-HCO3-CI, Na-HCO3-CI. Hot-waters in the region acquired by weld and draw well, their surface temperature are between 16-239 centigrate degree. Average temperature of cold-waters are 23 centigrate degree. Different geothermal techniques and their applicabilities have been examined, reservoir rock temperature of the system has been estimated 50-270 centigrate degree according to silica geothermometer and 150-270 centigrate degree according to NA/K geothermometer. The thermal waters in the study area show high borate concentration. The thermal waters should cause borate pollution in the Büyük Menderes basin. For this reason thermal water in the area must be re-injected after the uses of the energy producing heating, greenhouses