Hydrogeochemical investigation of the kolan (karakoçan) thermal and mineral water springs

ABSTRACT Ph. D. Thesis HYDROGEOCHEMICAL INVESTIGATION OF THE KOLAN (KARAKOCAN) THERMAL AND MINERAL WATER SPRINGS özlem ÖCTEKİN OKAN Fırat University Graduate School of Natural and Applied Sciences Department of Geological Engineering 2004, Page: 99 1/25 000 scaled geological map of the study area about 45 km2 was drawn, geology and hydrogeology cross-sections were prepared, chemical and isotopical compositions of the waters were determined within the scope of the study which aims of determination of the hydrochemistry of the Kolan (Karakocan) Thermal and Mineral Water Springs. In the studied area from bottom to top Permo-Trias Keban metamorphites, Lutesian- upper Oligocene Kırkgeçit Formation, upper Miocene lower Pliocene Karabakir Formation and Quaternary alluvium and travertines are present Alluvium passes laterally into the travertines. The recrystallized limestone of Keban metamorphites is overlain with a tectonic uncorformity by Kırkgeçit Formation which consists of conglomerate, sandstone, marl, limestone alternations. Keban metamorphites and Kırkgeçit Formation are overlain by an angular unconformity by Karabakir Formation. The boundary between Karabakir Formation and Keban metamorphites is also tectonic. Karabakir Formation is represented by conglomerate, sandstone- limestone alteration and laterally transitive limestone and tuff, tuffite, aglomerate and basalt alterations. The aquifer formation of the Kolan and Bağın thermal and mineral water is the recrystallized limestones of Keban metamorphites. The impermeable units of Kırkgeçit Formation are the nap rocks of the aquifer. Total mineralization of Kolan and Bağın thermal and mineral waters is between 3371,9 mg/1 - 4695,3 mg/1 and their temperatures range from 38 °C to 46 °C. The most abundant ions in waters are Ca+2 and HC03". The waters are classified as "Ca, Mg, HC03 and C02 bearing XTVthermal and mineral waters" on the basis of IAH classification. It was concluded by the geothermometer studies that the mean temperature of the reservoir in the Kolan geothermal field is 67 °C. Saturation calculations indicate that waters are over saturated with respect to calcite, dolomite, aragonite and quartz and are under saturated to anhydrite, gypsum, halite and chalcedony. Due to the super saturation with respect to CaC03 there is a thick tuff and travertine deposit formed around the Kolan and Bağın thermal waters. Three protection zones are determined for the Kolan and Bağın thermal and mineral waters. In the Kolan geothermal field, meteoric waters percolating through the permeable zones such as bedding planes and fault fracture lines in the syncline in recrystallized limestones of Keban metamorphites, react with rocks in which they circulate. As a result of water-rock interaction, the "waters that are heated by geothermal gradient become mineralized, and rise to the surface along the fault zones cutting the syncline axis. On the basis of isotope studies, Kolan and Bağın thermal and mineral waters are of meteoric origin deeply circulated waters, recharged from high elevations and are mixed with cold waters in a little proportion. Kolan and Bağın thermal and mineral waters are used for drinking and balneologic purposes. But, in order to create more favorable conditions for suburb people to utilize these spring waters, the construction of modern facilities around the springs is necessary. These waters can be used in greenhouses and C02 gas in the area can also be used for the production of dry ice. Key Words: Kolan, Bağın, Karakocan, Thermal and Mineral Water, Isotope, Geothermometer, Protection Area. XV