Provenance Study for Prehistoric Obsidian in Baekdusan, Kyushu and Hokkaido Using Mossbauer Spectroscopy

The iron compounds in minerals of obsidians from the continental Far East, Mount Baekdu near the Sino-Korean border, Kyushu in southwest Japan, and Shirataki, Japan were analyzed using ? Fe Mossbauer spectroscopy. The mineral Pyroxene (FeSiO ? ) in obsidian was found in the metamorphic rocks of Mount Beakdusan, Kyushu, and Hokkaido. However, the mineral biotite in obsidian was found in Kyushu only. The main phases of the Hokkaido obsidians are olivine, pyroxene, magnetite, and nano-oxide. Some Hokkaido obsidian showed the presence of hematite. In obsidians, iron species are mostly hosted by divalentions of olivine and pyroxene. In mineralogical and geochemical studies on obsidian from the continental Far East, the origination of the magma compositions and the crystallization environments were confirmed to have been different.