Palynostratigraphic study of the coal-bearing formation in Iki Island

The coal-bearing formation was found newly from two boring wells (ID-02 and ID-03) attaining a depth of 400 meters which were dug out by the International Highway Construction Corporation and the Japan-Korea Tunnel Research Institute. The author has examined palynologically twenty-seven samples from the boring well ID-02 and nine from the boring well ID-03. Each pollen assemblage from both boring wells excepting three samples from 54.5m-52.5m in depth of the ID-02 shows a predominance of Caryapollenites simplex simplex (Carya) and Periporopollenites stigmosus (Liquidambar) and belongs undoubtedly to the Carya-Liqudambar zone of the middle Miocene. Pollen assemblage from 54.5m-52.5m in depth of the ID-02 is characteristic of rare appearance of Caryapollenites simplex simplex (Carya) and dominance of Periporopollenites stigmosus (Liquidambar). Judging from a characteristic of the pollen assemblage and other geological-stratigraphical sequence, this pollen assemblage may be the Early Pliocene in age