Abstract
Pleistocene paleogeography and paleoenvironment of the Japan Sea have been investigated by several authors on the basis of the geological and geomorphological records on the surrounding land areas as well as of sediment core analyses. Recent works have elucidated the paleo-oceanographic history of the Japan Sea from the last Würm glacial to the postglacial by means of dated marker tephras, microfossils and oxygen isotope analyses of some piston-core samples. According to OBA (1983), the Tsushima warm current had begun to flow into the Japan Sea by 8, 000 years B.P. Before then, the Japan Sea was an enclosed cold sea (60, 000 to 30, 000 years B.P.) or a cold sea of low salinity (30, 000 to 20, 000 years B.P.), and an influx of the Oyashio cold current had begun to flow into the Japan Sea at 20, 000 years B. P. (Fig. 6).
