[U-06] 宇宙・太陽から地球表層までのシームレスな科学の新展開

[U06-P08] 火葬骨の炭酸ヒドロキシアパタイトを用いた14C年代測定の試み

*椋本 ひかり¹、南 雅代²、中村 俊夫²、鍵 裕之³ (1.名古屋大学理学部地球惑星科学科、2.名古屋大学年代測定総合研究センター、3.東京大学大学院理学系研究科地殻化学実験施設)

キーワード：骨, 炭酸ヒドロキシアパタイト, 14C年代測定

Bones are one of the most important materials for archaeological and paleo-environmental dating because they can directly provide absolute dates themselves. Bone collagen, which contains bone protein that is less susceptible to chemical weathering, is commonly used for ¹⁴C dating, but it sometimes has lost organic protein due to post-depositional chemical alternation and diagenesis, resulting in impossibility of ¹⁴C dating. For the bones remaining no organic component, carbonate hydroxyapatite, an inorganic component, is useful for ¹⁴C-measurement. However, the inorganic component in bones can easily be altered by acidic soil, and it has been considered to be unsuitable for ¹⁴C dating. Recently, meanwhile, it is reported that ¹⁴C dating using carbonate hydroxyapatite is possible for cremation bones heated at a high temperature (>600℃). The objective of this study is to examine the possibility of ¹⁴C dating using carbonate hydroxyapatite in cremated bones. The samples used were cremated bones in an um, which are considered to be remains of Jokei, a Buddhist monk (AD 1155-1213). The bones had been possibly heated at high temperature, judged from the IR spectrum and XRD pattern. The carbonate hydroxyapatite in six bone fragments showed ¹⁴C dates of 1155-1280 cal AD, which is similar with the supposed age. The result indicates that ¹⁴C dating using carbonate hydroxyapatite is effective when the bone sample was enough heated and well-preserved after deposition.