2023 Volume 74 Issue 3 Pages 119-131
The Cenozoic strata, excluding terrace deposits and alluvium, in the eastern area of the Hokuriku sedimentary basin, central Japan, consists of the Nirehara, Iwaine, Kurosedani, Higashibessho, Tenguyama, lower Otokawa, upper Otokawa, Mita and Kurehayama formations in ascending order. In this study, the stratigraphic correlations among the Higashibessho, Tenguyama and Otokawa formations in the Yatsuo area are examined in terms of the type area and the strata present in east of Yatsuo area. Nineteen samples for diatom fossil analysis were collected from the Kushida, Kitayama, Kurokawa and Hieda areas. The Shakusenji Formation in the Kurokawa and Kiyayama areas is correlated with the Denticulopsis lauta Zone (NPD4A). On the other hand, diatom fossils are not found in the Otokawa Formation．The following conclusions are obtained in this study. The Higashibessho Formation is correlated with the Shakusenji, Sasagawa and lower Sazen formations. The Tenguyama Formation is contemporaneous with the upper Sazen Formation, but heterotopic facies. The Lower Otokawa Formation is correlated with the Takabatake Formation but is not distributed east of Yatsuo area to the Kurokawa area. The Upper Otokawa Formation extends to the Hayatsuki River, but not further north.
