Radiocarbon dating for paleoenviromental peat archive: the case study using cellulose from peat core reached to 15ka in northern Japan

Peat sediment is one of the most important archives to reconstruct a past climate. From previous study, we found that stable carbon isotope ratio (δ13C) of peat cellulose is used as indicators of East Asian monsoon variability since the last deglaciaion including abrupt climate change (Shinozaki et al., in submission). The δ13C values recorded variability of rainfall amount related with Northern hemispheric climate change including Asian monsoon. Thus, it is crucial to establish correct age model with decadal to centennial time resolution. However, peat exists in forms of matrixes of organic matter such as intact plant and plant debris with soil mineral. In this study, we present radiocarbon dates of intact plant (Sphagnum), plant cellulose, and bulk organic matter from same horizons of peat core to investigate adequate dating candidates. Results of radiocarbon dates from plant cellulose were compared with those of bulk organic matter and intact plant (sphagnum). In addition, we tried three cellulose extraction methods to decide the most suitable one. To check their purity, results of recovery rate (%), TOC (%), TON (%), δ13C (‰) and NMR measurements were discussed.