The Anatolia region is one of the most seismically active regions in the world. It has a considerably high level of geothermal energy potential thanks to its geological and tectonic settings. The Southeastern Anatolia Region (GAP) is located in the south of Bitlis-Zagros Suture Zone (BZSZ) which is in the Arabian foreland. During the neotectonic period, the folded structures have been developed under the influence of tectonic compression from the Upper Miocene in the GAP Region where it is closely related to active tectonics. These tectonic activities produce more geothermal resources. Few studies have been carried out in this region for geothermal energy. Limited portions of the geothermal resources have been used both for thermal tourism and greenhouses in the GAP region. The aim of this study is to determine geological, tectonic and hydrogeochemical properties of a geothermal system in the GAP Region. The result indicates that the surface temperatures of geothermal fluids are from 20 to 84.5°C A large number of abandoned oil wells, whose temperature reaches 140°C, are found in the region. Also, hydrogeochemical results show that deep circulated geothermal fluids are enriched with Na-Cl and shallow geothermal system fluids have Na−HCO 3 and Ca-SO 4 characters because of cold water mixing and water-rock interaction. Cold waters are generally of Ca-Mg−HCO 3 and Ca−HCO 3 type. Cation geothermometers were used for determining reservoir temperature of the geothermal resources in the region. The results show that the reservoir temperature of these geothermal resources ranges from 50°C to 200°C. The isotope data (oxygen-18, deuterium and tritium) suggests that geothermal fluid is formed by local recharge and deep circulation.

Geothermal energy is a natural resource that can be utilized directly or by converting to other types of energy. Considering the diversity of the geological structure of Türkiye, the geothermal systems have developed depending on young tectonic and volcanic active rock. Western and Central Anatolia are especially rich in geothermal resources. The geothermal well with the hottest well-bottom temperature was drilled in Central Anatolia, and the well-bottom temperature was measured as 341°C at a depth of 3845 meters. In 2022, Türkiye's electricity generation capacity and the total installed direct heat use reached 1663 MWe and 5113 MWt, respectively. Considering Anatolia's Curie depth and heat flux, the probable thickness of the batholith can be regarded as 10 km. For example, the total granitoid area of Western Anatolia is 4221 km2, and at least 2% of this granitoid can provide approximately 8x107 MWh of electricity by Enhanced Deep Geothermal Systems (EDGS). When all granites in Türkiye are considered, it is expected that the future capacity of Türkiye will be much higher with drilling research and development studies and the discovery of new fields. This capacity will exceed 100,000 MWt levels in the medium term, especially with the addition of EDGSs.