Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Poster

H (Human Geosciences) » H-QR Quaternary research

[H-QR04] Quaternary, Diachronic dynamics of human-environment interactions

Sun. May 20, 2018 10:45 AM - 12:15 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Mamoru Koarai(Earth Science course, College of Science, Ibaraki University), Toshihiko Sugai(Department of Natural Environmental Studies, Institute of Environmental Studies, Graduate School of Frontier Science, The University of Tokyo), Kiyohide Mizuno(国立研究開発法人産業技術総合研究所地質情報研究部門, 共同), Minoru YONEDA(The University Museum, The University of Tokyo)

[HQR04-P15] High precision radiocarbon dating of marshland sediments using peat samples

*Yosuke Miyairi1, Reisuke Kondo2, Hiroko Fujita3, Yusuke Yokoyama1 (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.Educational Development Center, Kogakkan University, 3.The Field Science Center for Northern Biosphere, Hokkaido University)

Keywords:AMS, Radiocarbon dating, Peat deposits

Peat deposits developed in marshland are easy to measure radiocarbon dating. However, peat samples have uncertainty in estimating age that the source of carbon supply is secondary because the organic matter used for analysis is not the body of the living being but the substance decomposed and transformed of the biological bodies. In anaerobic environments where peat is deposited, biological disturbance hardly occurs, and the deposition rate often does not change much. Also, even if the deposition rate changes, according to the law of superposition, so that it is possible to obtain a sample with sufficiently shorter chronological intervals than the fluctuation cycle of radiocarbon concentration.

In this study, we examined the highly accurate radiocarbon dating of marshy sediments using peat samples, using samples in drill cores collected at the Saruto River Marshland in the northern part of Hokkaido. In addition to the bulk peat sample, plants and aquatic plants were used for dating samples. The AMS 14C age was measured by the single stage accelerator mass spectrometer owned by the Analytical Center for Environmental Study, Atmosphere and Ocean Research Institute, The University of Tokyo.

In the age analysis of algae, it is presumed that the research area was the brackish water area, so the old salinity concentration (Sagayama et al. 2018) restored by the diatom analysis from the core sample obtained from the same wetland By using the brackish water environment to estimate the contribution rate of the reservoir effect of sea water and atmosphere, we confirmed the possibility that the calendar age can be estimated accurately.

In this presentation, we will discuss the possibility of high precision radiocarbon dating of marshy sediments using peat samples, taking samples in boring core taken at Sarutake River Marsh as examples.