Characterization of the Bazman geothermal field, the southeast of Iran

Abstract

The Bazman volcano in the southeast of Iran is considered to be a dormant volcano. To study the hydrogeochemistry and geothermometry, sixteen water samples were collected from the thermal and cold springs. Temperature of the cold springs range from 28.1 to 36.6 C while mean temperature of the thermal spring waters is ~42 C. Generally, the salinity values of the water samples vary from 1102 in the cold spring to 10250 µS/cm in the thermal springs. The water samples are categorized into three types: Cl -Na, Cl-HCO3-Na-and SO4-Na. The composition values of δ2H and δ18O in the thermal springs were resulted from water-rock interaction or underground evaporation in the deep depths. Since the thermal springs have a different temperatures but similar chloride content, it seems that a conductive cooling mechanism is occurring in the geothermal system. Based on the geothermometry results, the equilibrium temperature of the deep reservoir estimated from ~120 to 145 C. The fraction of the cold water mixed with the warm water ascending is estimated to be ~0.94. Finally, the depth of thermal water circulation is estimated to ranging from 1.9 to 3 km under two different scenarios.