[SGC45-P02] Origin of Helium and CO2 Gas from Natural Carbonated Waters in the North-Eastern Area of South Korea.
Keywords:carbonated waters, CO2 gas, δ13C , 3He/4He ratio
The composition of carbonated waters can be classified into three chemical types; Ca-HCO3 water, Ca(Na)-HCO3 water, and Na-HCO3 water. Most of the carbonated waters are characterized a high CO2 concentration (PCO2 0.12 atm to 5.21 atm), a slightly acid pH (5.19 to 6.47), and high ion concentration.
Oxygen and hydrogen isotope data indicates that the carbonated waters are of meteoric origin. δ13C data of –6.6 to –0.3‰ suggest that the CO2 gas in carbonated waters is mainly derived from a deep-seated source, but is partly mixed with CO2 derived from carbonate rocks. The 3He/4He ratios of carbonated waters range from 1.51x10-6 to 8.38x10-6. The data are mainly plotted along the air-mantle mixing line on the 3He/4He versus 4He/20Ne diagram. These data strongly supported the deep-seated origin of CO2 gas by δ13C data.