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[AHW24-10] Isotopic characteristics of acid springs in Shunomata river basin in Mt. Chokai volcano
Keywords:acid springs, environmental isotopes, limonite ore deposits, Mt. Chokai Volcano
Temperature and pH of the acid springs showed 15.5 to 19.5 degree Celsius and 2.8 to 3.0, respectively. As for major dissolved ions, groundwater quality was characterized by high concentrations of SO42- and Cl (117 to 181 mg/L and 66 to 106 mg/L). Comparing these results with that of "Detsubo" spring that is located on the north side of Mt. Chokai volcano and is famous for low temperature (about 7 degree Celsius) and low pH (about 4.5), groundwater quality was largely different. Stable isotopic ratios of oxygen and hydrogen were about -11.5 per-mil and -68 to -69 per-mil, respectively. Elevation of recharge area of the acid springs was estimated more than 1,600 masl.
The results of this study suggest that there are some groundwater quality evolution systems of acid springs in Mt. Chokai volcano.