抄録
Carbonate minerals are ones of the most ubiquitous authigenic minerals in the sedimentary rocks. Therefore, we studied these minerals in order to clarify the retardation effect of radioactive elements, Am and Cm due to the incorporation of rare earth elements into carbonates. The light rare earth element concentrations of carbonates in the sedimentary rocks in Tono uranium mine area, central Japan, are high compared to those of the bulk rock. Since light rare earth elements are chemical analogues to Am and Cm, it is likely that carbonates easily incorporate them. Therefore, it is expected that incorporation of Am and Cm into carbonates can retard long-term migration of these elements. Calculations of the partitioning of rare earth elements between carbonates and groundwater suggest that the ionic radius and charge influence significantly the incorporation of Am and Cm into carbonates under actual underground geological environment.
