1993 Volume 38 Issue 38 Pages 85-93
The Plio-Pleistocene Osaka Group is developed in the central part of the Kinki District. The group consists of nonindurated gravel, sand, silt and clay beds, deposited in fluvial, lacustrine and shallow-marine environments, and includes, also, more than 45 volacanic ash beds. The author carried out a detail study of the succession just above and below the Fukuda volcanic ash layer, in the southern part of Kishiwada City, Osaka Prefecture, for reconstruction of sedimentary environments.
Within an area of 6×1km2, ten sedimentary facies were distinguished. These facies can be grouped into five facies associations, according to the coexistence of sedimentary facies. According to succession of facies associations and lithostratigaphy, the Osaka Group in the study area consists of sediments of two sedimentary environments: river channel and bars of intermediate to low sinuosity and high braiding parameter, and flood plane with the ephemeral channel of low sinuosity and high braiding parameter.
