RADIONUCLIDES IN ANCIENT RELICS OBTAINED FROM THE MATSUSAKI SITE AND THE HIROHATA SHELLMOUND ON THE PACIFIC COAST OF JAPAN

We compared 2 archaeological relics of different preservation environments, white substances adhering to a vessel from the Matsusaki site and to earthenware from Hirohata, by measuring their environmental radioactivity, (14)C, (228)Ra/(226)Ra, (234)U/(238)U, and (87)Sr/(86)Sr, and major element contents (Ca, Sr, Mg, Fe, and Mn). The results showed that the 2 materials were somewhat different and also reflected differences in their preservation environments. The chemical elements that were more abundant in the Matsusaki sample than in the Hirohata sample, Fe, Mn, (238)U, and (232)Th (parent of (228)Ra), are also abundant in seaweed or seagrass. Contamination by (14)C derived from rainwater after atmospheric nuclear tests was clearly observed in the white substance from Hirohata.