| Title | Hydrogeological Investigation of the «avundur-«erkes Geothermal Field, North-West Turkey |
|---|---|
| Authors | Mehmet «elik, Oktay «elmen, G¸rhan Rahmi KoÁbay |
| Year | 2005 |
| Conference | World Geothermal Congress |
| Keywords | «avundur-«erke, geothermal field, thermal and mineral water, isotope, hydrochemistry, shallow and deep cycled waters |
| Abstract | The study area is located at Ulusu Fault which is parallel to and some 15 km south of the North Anatolian Fault. The reservoir rock is the limestone of Dumlupınar Formation of Jurassic-Cretaceous age, constituting the base of the stratigraphic sequence as well. Basalt, agglomerate and tuffs of Miocene age are widely exposed and of low permeability. Marl of Miocene age is a confining unit with very low permeability. This level is overlain by conglomerate, sandstone and mudstone of permeable rocks recharging from the recent ground water. The groundwater in the study area is divided into two subclasses of shallow and deep cycled. Waters of shallow cycled consist predominantly of Ca2+ and HCO3-, whereas the waters of deep cycled are Na+ and HCO3- rich waters. Waters of deep cycled emerges usually around Ulusu fault zone. Amongst these hot springs, the «avundur spa has a discharge rate of 47 l/s and 54oC exit temperature which is utilised as balneological purposes. In the same area, there exist a cold spring with mineral water and a low discharge rate. Isotope analyses suggest that «avundur spa waters has the interaction of water-rock, whereas the springs of Ulupınar-Balıklıgˆl and Kˆsehamamı are deep cycled and of meteoric origin. The source of heat for the termal and mineral waters is the geothermic gradient as well as volcanic activities. Upon the silica geothermometers, it was predicted that the highest temperature for the «avundur reservoir is about 92oC. Physicochemical parameters, pH, EC, and T, were analysed insitu by Hanna instrument. All of the other hydrochemical parameters were analysed in Water Quality Laboratories of Ankara Metropolitan Municipality. Deuterium, oxygen-18 and tritium analyses were done by isotopic laboratories of General Directorate of State Hydraulic Works. |