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Majid Vanaei, Geological Gurvey of Iran (Islamic Republic of Iran)
Abbas Maghsoudi, Geological Gurvey of Iran (Islamic Republic of Iran)
Abdulsamea Saeedi, Geological Gurvey of Iran (Islamic Republic of Iran)
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Mt.Sabalan lies on the South Caspian plate, which underthrusts the Eurasian plate to the north. in the Sabalan Area There is a three Phase volcanic Activity. That Contain of Latite , Basalte ,Andesite , Dasite With Plio-Quaternery Age . Quaternary Series includes alluvium fans and terrace deposits and thin airfall ash interlayered with thick lahar and debris flows.In Sabalan Area Major of the hydrothermal alteration is Alunitization and Silisification.
Sabalan Zone is Affected by Faults Grouped in Four Families Terending.NW-SE,NE-SW,N-S and NNE-SSW.NE-SW Faults Played an Important role in the Emission of Volcanices From the Sabalan.The Ghtorsoyeh,Chay Khan, MoilSoyeh, PyrYar, Moil I, Moil II, and Ilando springs produce Cl-HCO-3 and less SO42- waters With Temp- erature between 6.5oC and 85oC. Thermal waters from springs are dominated by Ca2+, HCO3-,So42-and less Cl- . The chemistry of these thermal waters is Steam Heated Water and Peripheral Water and probably dominated by a combination of mixing with cold waters, mineral dissolution-saturation reactions and ion exchange reactions. Boron concentrations of thermal waters of the Sabalan geothermal fields are High.Probaply Illites,Biotite and Green Amphibole in host rocks could be the boron supplier for waters in the study area. Bicarbonate ions only in the Solfate,Calcium hot springs have shown a remarkable increase in the winter season and the Other hot springs Bicarbonate ions Decrease in the winter season . all the thermal waters in the study area are sodium Solfate and Calcium bicarbonate water types. Thermal waters(>20 C) of Sabalan geothermal fields are Undersaturated with respect to calcite and aragonite and undersaturated for gypsum and anhydrite . Calcium-SO4 or Sodium-SO4 waters with pH 2.7-5.3 Probably have formed by condensation and oxidation of H2S.The Bicarbonate-Calcium Some Samples have been slightly neutralised and are therefore further from the source of H2S . isotopically the waters lie on the local meteoric water line. The least diluted analysis that contains tritium at below detection limit and therefore contains no young groundwaters.The Distribution Pattern of Minor Elements With Cl is Similar. Indicated That Their Concenteration in Water May be Regulared by Water -Rock Interaction. At Low Temperature and Surface Water Dissolution Reaction Seems To Control The Aqueous Na/K Ratio. therefore Low Ratio Na/K May Reflected Higher Temperature at Level Deeper or Non Equilibrium Conditions With Respect to The Alkali-Feldespar and High Ratio Na/K May be due to Partial Re- Equilibrium Conditions in The Depressurization Zone Around The Origional Source For This Samples. The Entalpy Silica Mixing Model is Based on Heat and Silica Balance And is Useful to Evaluate The Mixing Ratio of Cold And Heat Water Components of Mixed Water and The Reservior Temperature.(Filiz et al 2000).The Reservoir Temperature Were Found Between 135 to 205 and 60 to 145.
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