RADIONUCLIDES IN ANClENT RELICS OBTAINED FROM THE MATSUSAKI SITE AND THE HIROHATA SHELLMOUND ON THE PAClFIC COAST OF JAPAN

摘要

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.