Quantitative analysis of land transformation in a Holocene delta: An example from the Tama River lowland, central Japan

Hasada, Kodai; Hori, Kazuaki

doi:10.1016/j.margeo.2020.106193

Cited by 5 publications

(2 citation statements)

References 30 publications

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“…1b) [26]. The sea oor sediment in Tokyo Bay consists mainly of mud from the coast to the center of the bay at -30 m (all depths are reported relative to mean sea level at the Tokyo Peil) [26]. In the abandoned river mouth of the pre-diversion Tone River, delta-front sand is distributed at depths shallower than -12 to -13 m [10].…”

Section: Coastal Lowlands North Of Tokyo Baymentioning

confidence: 99%

“…The largest river owing into Tokyo Bay today, in terms of runoff, is the Tama River, which has a catchment of 1,240 km 2 , runoff of 40 m 3 /s, and sediment discharge of 570 × 10 3 t/yr (18 kg/s) (Fig. 1b) [26]. The sea oor sediment in Tokyo Bay consists mainly of mud from the coast to the center of the bay at -30 m (all depths are reported relative to mean sea level at the Tokyo Peil) [26].…”

Section: Coastal Lowlands North Of Tokyo Baymentioning

confidence: 99%

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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: Coastal Lowlands North Of Tokyo Baymentioning

confidence: 99%

Section: Coastal Lowlands North Of Tokyo Baymentioning

confidence: 99%