Hydrogeochemistry of the Saraycik geothermal area (Manisa) Western Turkey

Hydrogeochemical study of thermal waters has been carried out in Saraycik geothermal region, Western Turkey, The geology is dominated by metamorphic rocks of Menderes Massif and overlying Neogene sedimentary and volcanic rocks. Thermal waters issue from fractured zones associated with active faults trending N-S. Thermal waters are of Na-HCO3-SO4 type with TDS of 6500 mg/l and with temperatures varying between 40 degreesC and 74 degreesC. The thermal springs have relatively low Cl values (130mg/l), but are rich in Na (1750 mg/l) and HCO3 (2600 mg/l). The dominant water-rock interactions are the carbonate dissolution and ion exchange reactions between Na and Ca and/or Mg resulting an increase in dissolved minerals and conversion into sodium bicarbonate type water. Thermal waters are undersaturated with respect to gypsum and oversaturated for calcite and dolomite giving rise the travertine formation along the fault zone. Assessment of geothermometry results applied thermal waters showed that reservoir temperature is estimated about 120-160 degreesC