HOLOCENE PULSES OF DIATOM GROWTHS IN THE WARM TSUSHIMA CURRENT IN THE JAPAN SEA

Abstract

Rhythmic fluctuations of diatom temperature values (Td=X_w/(X_w+X_c), where X_w is the frequency of warm water species and X_c that of cold water species) are recognized in three cores: KH-79-3, L-3 from the southern part of the Japan Sea, KH-86-2, St.9 from the middle part, and KH-84-3, St.33 from the northern part, that is the western part of the Tsugaru Strait. Four peaks of Td values occur during the post-glacial period; they correlate between the cores and indicate a strong inflow of the warm Tsushima Current (warm periods) into the Japan Sea. The rhythmic fluctuations can be compared with palaeo-temperatures based upon oxygen isotope ratios and sea-level changes in the Japan Sea. It seems likely that such climatic fluctuations are synchronous with glacial fluctuations and changes in the forest-limit in the European Alps during the Holocene.