Abstract
The sedimentary core GS-KSO-1 is obtained in Shimo-oibukuro, Kawagoe City in the Arakawa Lowland, central Japan, which is a part of the research project to construct a depositional model of the latest Pleistocene to Holocene incised-valley fills. The stratigraphy and sedimentary environments have been revealed based on sedimentary facies, grain-size distribution, CNS analysis, and radiocarbon dating.
The valley fills in GS-KSO-1 are subdivided as follows; gravelly river deposits, sandy channel fills, floodplain deposits (9000 cal yBP), backmarsh to salt marsh deposits, tidal flat deposits (8000 cal yBP), backmarsh deposits (7000-6000 cal yBP), channel fill deposits and floodplain deposits (6000 cal yBP to present).
The age of the maximum flooding surface in the Arakawa Lowland is determined as 8000 cal yBP, which is 1000 to 2000 years earlier than that in the neighboring Nakagawa Lowland. This gap is possibly due to relatively large amount of sediment supply into the Arakawa Lowland.
