[AHW24-P06] Geochemical characteristics and origin of groundwater in central to eastern Hokkaido
The concentrations of dissolved major elements such as Cl, suggested that groundwater in Hokkaido is mainly of seawater origin. The δ18O and δD values, however, indicate that the fluid also contains meteoric water. The redox condition of deep environment had changed the concentrations of Mn and SO4, and the weathering of sedimentary rocks had increased the amount of Si, respectively. Iodine was significantly enriched compared to seawater, resulting from the deposition of I-rich marine algae in the internal shallow water zone. Concentrations of trace elements such as Pb, Zn, and Li vary among sampling locations, which indicates elution of Pb and Zn by the weathering of minerals, and release of Li from clay minerals in high temperature environment.