Flow patterns at the Tuzgle-Tocomar geothermal system, Salta-Jujuy, Argentina. An isotopic and geochemical approach

Environmental isotopes 3H, 2H and 18O, major and minor anions and cations, and gas analysis have been made in order to establish hydrological conditions and reservoir temperatures. Isotope contents of waters, 2H, 18O show good correlation with altitude and allow to differentiate the possible recharge areas. Due to the rigorous weather conditions prevailing at the high altitud in the Puna environment i.e. great thermic amplitude, low precipitation, low humidity and atmospheric pressure, gross kinetic fractionation mainly in oxygen-18 has been found. Chemical of dissolved solids and gas geothermometers define the area as a low to medium entalpy with reservoirs temperatures range from 90 to 140 deg. C. Circulation of cold and hot water shows a pattern where are recreated most of cases of stable isotope fractionation. (author). 7 refs, 10 figs, 6 tabs, 3 maps