| Abstract |
In West Anatolia, there is a 3-30 km wide and 500 km long, NW-SE-trending normal fault system surface. This large seismogenic zone is called as Akşehir Simav Fault System (ASFS). With a length of 130 km and a width of 4-20 km, Afyon-Akşehir Graben is one of the most important graben and geothermal systems in ASFS. The graben has a WNW–ESE trending structure bounded by normal fault systems. Ömer-Gecek, Gazlıgöl, Sandıklı and Heybeli areas are the most important geothermal areas associated with Afyon-Akşehir Graben faults. Hot and mineralized waters in the region are used generally for purposes of district heating, greenhouse and thermal tourism. In Omer-Gecek basin, existing outside the old well points, the new hot spots are being discovered and geothermal area are still being developed. Maximum temperature was measured at 125°C. It is planned to generate electricity, washing and drying from new wells from these new hot points. Depending on their depths, reservoir rocks and temperatures, thermal waters have different electrical conductivity ranging from 350-7820 µs/cm and compositions are quite diverse, whereas Omer-Gecek waters types are Na-Cl-HCO3, Sandıklı waters have Na-SO4-HCO3 type, Gazlıgöl waters have Na-HCO3 type and the Heybeli waters have Na-Ca-HCO3-SO4 type. The cold groundwaters are mostly dominated by Ca and HCO3 ions. According to Giggenbach diagram, while Omer-Gecek waters are both partially equilibrated and immature, Sandıklı-Heybeli and Gazlıgöl waters are immature. The silica geothermometer models suggest a reservoir temperature max.149°C for Omer-Gecek, max. 115°C for Heybeli, 123 °C for Sandıklı and 119°C for Gazlıgöl waters. |