Radiocarbon age offsets of plant and shell in the Holocene sediments from the central part of Sanriku coast, Northeast Japan

Dr. Toshimichi Nakanishi1, Dr. Yuichi Niwa2, Prof. Wan Hong3

1Museum of Natural and Environmental History, Shizuoka, Japan, 2Keio University, Tokyo, Japan, 3KIGAM, Daejeon, South Korea

To identify the chronological and spatial changes of the marine reservoir effect in the East Asia, the radiocarbon ages of pair samples of marine shells and terrestrial plants were measured from same horizons of Holocene sediment cores. This research project began in 2010 with a research on the Korean coast, and has established with research grants from the Japan Geographic Data Center, the National Research Council of Science & Technology of Korea and the Japan Society for the Promotion of Science. After explaining the outline of this research project in the southwest Japan [1-4] and the Korean Peninsula [5-7], a case study conducted in the Sanriku Coast of Tohoku region is introduced using three sediment cores [8-9]. The changes in depositional environment had been mainly associated by the sea-level rise during the last deglacial period. The reservoir ages of therty-seven pairs were obtained from the transgressive lag to delta front facies. The average value during 2000–9,000 cal BP was 420 ± 150 years within 100 ± 90 to 720 ± 60 years. The chronological change in the reservoir effect was consistent with the previous results in the Korean Peninsula and Southwest Japan such as the Hakata Bay, Oita Plain, Sukumo Plain and Miyazaki Plain. These relatively large variability of reservoir ages would reflect the sensitivity of the marine reservoir effect under the environment of warm Kuroshio and cold Oyashio Currents. This study was partially funded by the Japan Society for the Promotion of Science Kakenhi grant number JP18H01310.

[1] Nakanishi et al., 2017, Radiocarbon, 59(2), p.423-434.
[2] Nakanishi et al., 2017, Radiocarbon, 59(6), p.1737-1748.
[3] Nakanishi et al., 2019, Radiocarbon, 61(6), p.1939-1950.
[4] Nakanishi et al., 2019, Radiocarbon, 61(6), p.1951-1961.
[5] Nakanishi et al., 2013, Nuclear Instruments and Methods in Physics Research Section B, 294, p.573-578.
[6] Nakanishi et al., 2017, Quaternary International, 447, p.3-12.
[7] Nakanishi et al., 2015, Nuclear Instruments and Methods in Physics Research Section B, 361, p.670-679.
[8] Niwa et al., 2017, Quaternary International, 456(15), 1-16.
[9] Niwa et al., 2019, Quaternary International, 519(10), 10-24.


Biography:

Yonsei Universirt in Korea, Ba
University of Tokyo, PhD.
Director, Geochemical Analysis Center, KIGAM
Director, AMS Lab., KIGAM

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Date

Nov 08 - 19 2021