Difference in timing of maximum flooding in two adjacent lowlands in the Tokyo area caused by the difference in sediment supply rate

Komatsubara, Junko; Ishihara, Yoshiro; Nakashima, Rei; Uchida, Masao

doi:10.1016/j.quaint.2017.06.006

Cited by 11 publications

(1 citation statement)

References 28 publications

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“…The 45 cores used in this study were obtained or analyzed by the Geological Survey of Japan (GSJ) during 2002-2020, and sedimentary facies and radiocarbon dates from most of the cores have been reported in preliminary studies [10,[33][34][35] (Fig. 1, Table S1).…”

Section: Methodsmentioning

confidence: 99%

Recycling of clastics in coastal areas: Quantitative analysis based on reworked radiocarbon samples

Tanabe

Nakanishi

Nakashima

2021

Preprint

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Studies of the evolution of coastal lowlands since the Last Glacial Maximum (LGM) typically ignore radiocarbon data from sediment samples that have undergone reworking. However, these samples contain information on their sediment sources and their timing of redeposition. We analyzed 738 radiocarbon dates obtained from shell and plant material in samples of post-LGM coastal sediment from north of Tokyo Bay. Of these samples, 245 (33%) had reworked ages. Furthermore, the percentage of reworked samples and their average age offsets increased with the depth of the water environment (terrestrial, 15% and 360 ± 250 years, respectively; intertidal, 26% and 470 ± 620 years; subtidal, 39% and 550 ± 630 years). Taking these radiocarbon samples as a proxy for clastic material, our results imply that channel erosion accounted for relatively little clastic removal in the terrestrial and intertidal environments in short duration, whereas ~40% of clastics were removed by storm winnowing and transported in stepwise fashion to deeper water in long duration and ~60% were transported by floods directly from river mouths in the subtidal environments. These findings imply that radiocarbon ages from reworked samples can be used to quantify clastic recycling processes and their history in coastal areas.

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Section: Methodsmentioning

confidence: 99%