LATE CENOZOIC ZOOGEOGRAPHY OF THE SEA OF JAPAN AREA

The zoogeographic history of the Sea of Japan can be summarized as follows. From 17 to 15 Ma, before the spreading of the sea, tropical and subtropical mollusks invaded the area. The benthic and planktonic faunas changed sharply into temperate faunas at about 15 Ma, an event associated with the rotation of Japan and the opening of the Sea of Japan. From about 10 to 5 Ma, sedimentary deposits formed that were barren of benthic mollusks as a result of the stagnation of the Sea of Japan basin. Cold-water molluscan fauna reappeared in the coastal areas at about 5 Ma. This has been followed by a period of marked cyclicity of cold- and warm-water faunas since about 1.3 Ma.