RAW MATERIAL SOURCING OF OBSIDIAN ARTIFACTS EXCAVATED FROM THE SHIMOHARA - FUJIMICHO SITE IN TOKYO, JAPAN

We carried out nondestructive compositional analysis for 248 obsidian artifacts excavated from the Shimohara - Fujimicho site in Tokyo, Japan using a handheld energy dispersive XRF spectrometer, Delta Premium 6500. Calibrations for the XRF analyses were carried out using polished slabs of obsidians whose compositions had been determined with a wavelength dispersive XRF (WD –XRF) spectrometer, Rigaku ZSX primus II⁺, for flux-fused disks. Calibrations of the WD-XRF were carried out using synthetic standard smaples. Analytical results were compared with bulk rock compositions of obsidian raw materials distributed in central Japan. The comparisons indicate that the raw materials of the Shimohara-Fujimicho artifacts would have been collected from Hatajuku (n = 84) and the Kashiwa pass (n = 22) at the Izu-Hakone area, and Kita-Yatsugadake (n = 40), Hoshigato (n = 49) and Wada-Takayma (n = 50) at the Central Highland area.