New AMS Dates from the Shukubai-Kaso Site (Loc. Sankakuyama), Hokkaido (Japan): Refining the Chronology of Small Flake-Based Assemblages during the Early Upper Paleolithic in the Paleo-Sakhalin-Hokkaido-Kuril Peninsula

ABSTRACTThis paper reports accelerator radiocarbon dates obtained from 14 charcoal specimens recovered from the Shukubai-Kaso site (Loc. Sankakuyama), which was excavated in 1973. The small flake-based assemblage from the site has been chronologically attributed to represent the oldest archaeological occupation in Hokkaido. Because the new radiocarbon dates, stratigraphic sequences, and site context do not contradict each other, we conclude that the ages of the archaeological components in Layer III of Shukubai-Kaso (Loc. Sankakuyama) fall within the interval of 29,530 and 28,480 cal yr BP. These ages are close to previously estimated dates for other small flake-based assemblages including the Wakabanomori, Kamiitaira, and Kyu-Shirataki 3 sites. They are also 1500 years older than last glacial maximum (LGM) assemblages on the Paleo-Sakhalin-Hokkaido-Kuril peninsula. These new ages reliably place the small flake-based assemblages in the chronological phase prior to the onset of the LGM.