Abstract
Fossil freshwater diatoms from tuffaceous–terrigenous deposits of the Yamato Rise, the Sea of Japan are described. The diatom flora includes 133 species and intraspecific taxa belonging to 44 genera. Species of Aulacoseira (19 taxa) and Tetracyclus (17 taxa) are highly diversified, and species of Aulacoseira and Actinocyclus occur very abundantly. Aulacoseira is mainly represented by extinct taxa, including those with elliptic valves that are characteristic of the Early Miocene (23–16 Ma). Such findings of numerous fossil freshwater diatoms in the Yamato Rise deposits strongly suggest that, during the Early Miocene, the Yamato Rise contained a lake basin within a terrestrial environment. Fifty-seven diatom taxa are illustrated.
Acknowledgements
The author thanks very much F. Akiba (Diatom MiniLab Akiba Ltd., Japan) for critically reviewing the manuscript and providing useful discussion and suggestions. I am grateful to my colleagues from the Il’ichev Pacific Oceanological Institute for collecting geological samples from the Yamato Rise and L.V. Osipova for the processing of the samples for the diatom analysis.
Disclosure statement
No potential conflict of interest was reported by the authors.