신보활석광산 주변에 형성된 우라늄 이상치에 관한 지화학적 연구(II)- 동위원소적 특성을 중심으로 -

The purpose of this study is to elucidate the source of U anomaly formed in stream water of the drainage system around the Shinbo tale mine are based on the O, H, S and Sr isotopi characteristics of water masses and wall rocks. The δD and δ18O of surface and ground waters show highly restiricted range and plotted on the same meteoric water line, indicating that they are all originated from the meteoric water. The δ34S value of the ground water containing high U shows slightly negative (-0.2‰) and quite distinct from those of the other surface and ground waters that are similar to those of wall rocks (>5.8‰), indicating that they have a different S isotopic fractionation or less probably, source. The 87Sr/86Sr raios of water masses around the Shinbo talc mine area show a variable range from 0.724325 to 0.744928, but tend to increase with increasing U concentraion of water mass. Although it is not possible to determine precisely the surce rock of U anomaly formed in the hydrologic system around the Shinbo talc mine, the evidence obtained fron the Sr isotopic compositions strongly suggests that coal schist and/or pegmatite vein could be the most likely candidate for the source rock.