Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

M (Multidisciplinary and Interdisciplinary) » M-TT Technology & Techniques

[M-TT48] Frontiers in Geochemistry

Sun. May 26, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Hirochika Sumino(Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo), Tetsuya Yokoyama(Department of Earth and Planetary Sciences, School of Science, Tokyo Institute of Technology), Hajime Obata(Marine inorganic chemistry division, Atmosphere and Ocean Research Institute, University of Tokyo)

[MTT48-P06] Sequential radiocarbon measurement on peaty sediments to reconstruct high precision age model of mash deposits

*Yosuke Miyairi1, Reisuke Kondo2, Akihiro Yokota3, Kiyoyuki Shigeno3, Hiroko Fujita4, Yusuke Yokoyama1 (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.Kogakkan University, 3.Meiji consultant co.,ltd., 4.The Field Science Center for Northern Biosphere, Hokkaido University)

Keywords:Radiocarbon dating, Wiggle matching, Tephra

Peat deposits that develop in wetlands are easy to radiocarbon dating because they contain a lot of carbon. However, peat has uncertainty in estimating the age of sedimentation that the source of carbon supply is secondary, because organic matter is not a biological body, but mainly decomposed matter of biological bodies. Biological disturbance is unlikely to occur in an anaerobic environment where peat deposits. In addition, the deposition rate often does not change much. Even if the deposition rate changes, it is guaranteed that the sediments are older than the sediments in the lower layer, according to the law of stratum accumulation, so sampling should be done at period intervals much shorter than the fluctuation cycle of radioactive carbon concentration If you do, you will be able to determine high precision chronology.

Blaauw et al. (2003, QSR) compares the calendar year calibration curve with the continuously sampled radiocarbon dating values, assuming that the peat layer deposition rate does not change for a certain period, Can be estimated.

Although this approach has been tried (eg Ishizawa et al., 2017, QG) to apply tsunami sediments contained in peat deposits to high precision age dating, verification of accuracy using known age class I have not been touched.
Therefore, in this study, we aimed to verify the age determination accuracy by seeing the age by the peat-wiggle matching method for the tephra containing layer whose eruption age is clear by the history record.