<p>significant geothermal energy source field. The analysis of power spectrum,</p><p>conventional heat flow and silica heat flow methods were implemented to</p><p>identify the geothermal waters circulation depth, depth to Curie point and surface</p><p>heat flow rate in the Hüdai-Sandıklı geothermal field. Hydrogeochemical facies of</p><p>geothermal immature ancient waters having deep circulation in lower hydraulic</p><p>conductive aquifers are Na–Ca–HCO3–SO4 and Na–Ca–SO4–HCO3, which is</p><p>represented very high ion content because of extensive contact with rocks. The heat</p><p>conduction law is employed to specify the rate of heat flow using the geothermal</p><p>gradient value. The numerical results determined from silica geothermometer</p><p>method, the mean heat flow density and Curie temperature depth are obtained as</p><p>103:69mWm2 and 11.81 km, respectively. The study region was represented by a</p><p>mean geothermal gradient of 49.18 °C km−1 yielding average reservoir depths of</p><p>0.90 km. The estimated Curie temperature, heat flow, reservoir temperature values</p><p>demonstrated that the region indicates significant geothermal energy potential</p><p>because of the partial melting of lithospheric crust.</p>