種子島に分布する四万十帯南帯熊毛層群西之表層から得られた放散虫化石

抄録

We carried out geological and radiolarian studies in the northern part of the Nishinoomote Formation of the Kumage Group in the South Shimanto Belt, Tanegashima Island. The Nishinoomote Formation in the study area consists mainly of thick bedded sandstone and alternating beds of sandstone and shale with minor amount of varicolored shale. As a result of the radiolarian study, Late Eocene radiolarians such as Lithocyclia ocellus group and Lychnocanium neptunei were obtained from two samples of black shales, and Late Eocene radiolarians such as Lychnocanoma babylonis and Shiphocampe missilis were recognized in one sample of varicolored shale. In the previous study, Early Oligocene radiolarian fossils and calcareous nannofossils had been reported from the northernmost part of the Nishinoomote Formation. Therefore, considering the difference of depositional age and lithology, further study is needed to clarify the relationship between the northernmost part and the northern part of the Nishinoomote Formation.