Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Date (from‐to) : 2014/04 -2018/03
Author : WADA Keiji, SATO Eiichi, SATO Hiroyuki, ONO Akira, SANO Kyohei, NAKAZAWA Yuichi, AKAI Fumito, YAMADA Satoru, ODA Noriyoshi, YAMAHARA Toshiro, Ferguson Jeffrey R., Glascock Michael, Vasilevski Alexander A., Grishchenko Vyacheslav, Grebennikov Andrei V., McPhie Jocelyn
We clarified the internal structure of obsidian lavas from the following three localities; Shirataki in the north Hokkaido, Kozushima, one of the Izu islands, and the Kamchatka Peninsula in Russia. Based on the layer structure in obsidian lava and the rock texture and composition, we presented a formation model of obsidian caused by the promotion of outgassing and of rhyolite by leaving air bubbles through the cooling process of highly viscous magma.
We constructed a systematic archeological obsidian research in Hokkaido. We made it possible to identify the sources of obsidian artifacts by the most practical and accurate method of combining X-ray fluorescence and neutron activation analysis. Analyses of more than 3,400 obsidian artifacts of the late Paleolithic sites in Hokkaido suggest that the behavior pattern of the hunter-gatherer group and accompanying obsidian procurement behavior changes with time as a boundary at the late glacial maximum of about 20,000 years ago.