Geochemical Study of Mongolian Hot Springs

Abstract

In this paper presents data analyses seven hot spring samples from northern Khangai area, central Mongolia. The chemical composition of these waters was analyzed by standard methods and subsequently classified by the use of the Cl-SO4-HCO3 triangular diagram. The other basic diagram, Na-K-Mg, was used to classify waters according to the state of equilibrium at given temperatures. The geothermal water types are sulphate-sodium and bicarbonate-sodium. Chemical geothermometer were used on geothermal waters to indicate reservoir temperatures. Values for chalcedony geothermometer and Na/K geothermometer values are used to define the source temperature of the geothermal water component. The results could be an evidence of mixing with cold waters in all the fields which were studied. The Ryznar Stability Index (RSI) and WATCH program were used to interpret the equilibrium state of the reservoirs and to predict scaling tendencies. Calcite scaling occurs at the high calcite Saturation Index values and low RSI values. Hence these indices show geothermal waters of the Khangai area no scaling tendency.