[S-GL22] Geochronology and Isotope Geology

[SGL22-01] Tree-ring oxygen isotope dating of archaeological wood

★Invited Papers

*Masaki Sano¹ (1.National Museum of Japanese History)

Keywords:dendrochronology, oxygen isotopes, 14C spike matching

In warm and humid Japan, tree growth is controlled not only by climate but also by ecological competition with neighboring trees, resulting in lower inter-individual correlations in variations of tree-ring widths. Therefore, although ring-width master chronologies have already been developed over the past 3,000 years, there are significant limitations in tree species and the number of tree rings in a given sample to be used for tree-ring dating. On the other hand, oxygen isotope ratios in cellulose of tree rings, which are governed by relative humidity and oxygen isotope of precipitation during the growing season, are less dependent on tree species, and variations in oxygen isotope are well correlated among individual trees. In this report, we present recent progress in the development of tree-ring oxygen isotope datasets in Japan, and some results of dating for archaeological wood materials using those datasets. We also show the spike-match dating method based on annually resolved radiocarbon measurements of tree rings. Furthermore, since most of wood materials excavated from archaeological sites has tree rings of less than 50 years, isotope analysis based on such materials is also introduced as an effort to date those samples.