Pliocene diatoms from freshwater diatomite in Yamaga Town, Kyushu, Japan

Abstract

Diatomite outcrops at three sites, Oto r i, Noharu and Matsuo of Yamaga Town in Oita Prefecture, Kyushu, Japan, were investigated, and 94 taxa in 39 genera of freshwater diatoms were found from 7 samples taken at the three sites. Every sample contained a high frequency of the same centric diatoms, and the dominant species were Stephanodiscus komoroensis, Cyclostephanos kyushuensis and Aulacoseira sp. of which taxonomic information is presented here. The diatom assemblages of the 7 samples suggest that the d iatomite of all three sites were deposited in the same paleo-lake. This supports the result of a previous geological study that all of the three sites are from the same stratum.