Investigation of hydrogeochemical properties of Külcüler (Bayramiç-Çanakkale) geothermal field

Külcüler geothermal area, which is affected by the North Anatolian Fault?s western extensions and West Anatolian Graben systems, is located in Biga Peninsula. Külcüler (Bayramic-Çanakkale) geothermal spring, located approximately 17 km southeast of Bayramiç, is one of the important geothermal areas in Biga Peninsula. The lithologic units in the study area consist of granitic rocks (Evciler Plutonic) and Çan volcanic units which are upper Oligocene age. The Evciler unit mainly consists of granite. The Çan units consist of andesite, tuff and basalts. Granite rocks intersect volcanik rocks. Quaternary alluvium overlies these units unconformably. The average discharges of the thermal waters in study area are 5 lt/sec. They form a thermal bath at the Külcüler village where they discharge at the surface. The surface temperature of Külcüler spring?s are between 28-340C, pH values are 8.88-9.71 and electrical conductivity (EC) values are 885-1049 ?S/cm. The surface temperature of the cold water springs in the study area changes between 15- 240C, pH values 6.20-7.95 and electrical conductivity values 366-1287?S/cm. Hot water springs have basic character, and low electrical conductivy shows that they are not reacted with aquifer for a long time. The hot resources of geothermal area are granodiorite that is identified by outcrops in the northwest of study area. The reservoir rocks are volcanic which crop out in the southeast of the Külcüler hot spring where they contain many cracks. When results are plotted on piper and Schoeller diagrams it seen that hot and cold waters are enriched with Na-SO4 and Ca-HCO3, respectively. Thermal waters have the same recharge area, shallow circulation and meteoric in origin as depicted by their Oxygen 18 (18O) and Deuterium (D) contents. Tritium (T) isotope analysis results showed that hot waters are older than 50 years.