Land-ocean linkages over orbital and millennial timescales recorded in late Quaternary sediments of the Japan Sea

Late Quaternary sediments of the Japan Sea are characterized by centimeter- to meter-scale alternations of dark and light layers which are synchronous basinwide. High-resolution analyses ofthe sediments from Ocean Drilling Pr ogram site 797 reveal that deposition of the meter-scale alternations refle ct variations in paleoceanographic conditions which were closely associated with glacio-eustatic sea level changes through the modulation of the volum e and character of the influx to the sea through the Tsushima Strait. The c entimeter- to decimeter-scale alternations reflect millennial-scale variati ons which are possibly associated with Dansgaard-Oeschger (D-O) cycles, wit h each dark layer appearing to correspond to an interstadial. This variabil ity is attributed to the development of a humid climate in central to easte rn Asia and the consequent increase in discharge from the Huanghe and Chang jiang Rivers during interstadials. This caused expansion of the East China Sea coastal water (ECSCW), which penetrated more strongly into the Japan Se a. The increased influence of the lower-salinity, nutrient-enriched ECSCW r educed deep water ventilation and enhanced the surface productivity, leadin g to the development of anoxic bottom waters and deposition of the dark lay ers. Thus the centimeter- to decimeter-scale alternations of the dark and l ight layers record wet and dry cycles in central to eastern Asia possibly a ssociated with D-O cycles.