著者

阿久津 純 藤山 家徳

出版者

国立科学博物館

雑誌

国立科学博物館専報 (ISSN:00824755)

巻号頁・発行日

no.15, pp.p49-52, 1982-12

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The fossil lake of Oshino, northeast of Mt. Fuji, was caused by damming up of the Oshino lava, a basaltic lava flow of My. Fuji Volcano. The lake deposits of Oshino, about 11-12m in thickness, lie at a depth of 12-25m and dated 7,150±140 years B. P. by the ^<14>C method. The geological sequence in and around the Oshino basin and the pollen flora and the insect fauna of the deposits are reported in another paper in this volume. Forty-five species of fossil diatom are identified, and the most dominant species among them is Stephanodiscus dubius which has not yet been reported from recent lakes in Japan. Other planctonic species include Cyclotella comta, Fragilaria construens, Melosia granulata, Stephanodiscus astrara and Tabellaria fenestrata. Other spiecies are all epiphytic and occupy less than 10% of total individuals.