Japan Geoscience Union Meeting 2019

Presentation information

[E] Poster

H (Human Geosciences ) » H-CG Complex & General

[H-CG26] Deltas and estuaries: multidisciplinary analyses of complex river-mouth systems

Mon. May 27, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Yoshiki Saito(Estuary Research Center, Shimane University), Guan-Hong Lee(Inha University), David L Dettman(University of Arizona), Kazuaki Hori(Department of Geography, Graduate School of Environmental Studies, Nagoya University)

[HCG26-P03] Offset in radiocarbon ages between marine bioclast and terrestrial plant pairs in the Holocene sediments around Japan

*Nakanishi Toshimichi1,2, Futoshi Nanayama3,4, Atsushi Urabe5, Kazuaki Hori6, Wan Hong7 (1.Kyoto Univ., 2.JAEA, 3.AIST, 4.Kumamoto Univ., 5.Niigata Univ., 6.Nagoya Univ., 7.KIGAM)

Keywords:Radiocarbon age, Marine reservoir effect, Holocene, Kuroshio Current

To identify chronological and spatial changes in the radiocarbon (14C) marine reservoir effects, the 14C ages of eight pairs of marine bioclasts and terrestrial plants were measured from the same horizons of one core of Holocene sediments around Japan (Nakanishi et al. 2013, 2015, 2017abc). The reservoir ages ranged from 60 to 1100 years, scattered over the period 100-10,200 cal BP, which were significantly larger than the values from “prebomb” samples of known age, before AD 1955 in this area. These results indicate that the information on reservoir effects is indispensable for chronological control not only from prebomb samples but also from geological and archaeological samples. Moreover, the effects also reflects the influence of complex river-mouth systems such as deltas and estuaries. To determine the direct chronological changes of the marine reservoir effect between the Kuroshio and Tsushima Currents, radiocarbon ages from pairs of marine bioclasts and terrestrial plants were measured from the same stratigraphic horizons within three cores of Holocene sediments beneath the Sukumo Plain, Miyazaki Plain, and Oki Islands, in west Japan. Subsequently, the results were compared with values from the Oita Plain and Hakata Bay on the northern coast of Kyushu (Nakanishi et al. 2017ac), as well as the Korean Peninsula (Nakanishi et al. 2013, 2015, 2017b). The study was partially funded by the Japan Society for the Promotion of Science Kakenhi grant number 18H01310.

Nakanishi T, Hong W, Sung KS, Lim J. 2013. Radiocarbon reservoir effect from shell and plant pair in Holocene sediments around the Yeongsan River in Korea. Nuclear Instruments and Methods in Physics Research B 294: 444–51.
Nakanishi T, Hong W, Sung KS, Sung KH, Nakashima R. 2015. Offsets in radiocarbon ages between plants and shells from same horizons of coastal sediments in Korea. Nuclear Instruments and Methods in Physics Research B 361: 670–9.
Nakanishi T, Hong W, Shimoyama S, Sato S, Park G, Lee JG. 2017a. Radiocarbon age offset between shell and plant pairs in the Holocene sediments under the Hakata Bay, western Japan. Radiocarbon 59 (2): 423–34.
Nakanishi T, Hong W, Sung KS, Nakashima R, Nahm WH, Lim J, Katsuki K. 2017b. Offset in radiocarbon age between plant and shell pairs in Holocene sediment around the Mae-ho Lagoon on the eastern coast of Korea. Quaternary International 447: 3–12.
Nakanishi T, Takemura K, Matsuyama H, Shimoyama S, Hong W, Okuno M. 2017c. Activity of the Funai fault and radiocarbon age offsets of shell and plant pairs from the latest Pleistocene to Holocene sediments beneath the Oita Plain, western Japan. Radiocarbon 59(6): 1737–48.