High resolution climate and environmental changes of the northern Japan (East) Sea for the last 40kyr inferred from sedimentary geochemical and pollen data

Abstract

A High-resolution lithological and isotope-geochemical results of a well age constrained sediment core was raised from the northeastern Japan (East) Sea recording 10 dark layers (DL) over the last 40 ka BP. Pollen analysis of the core allows us to reconstruct the history of surrounding landmass vegetation and to determine pronounced vegetation/climate changes. We found that DL 10 correlated with a DO/Chinese interstadial 8 was forced by increased East Asian humidity and influx of the nutrient-rich water into the sea. DL5 formed during cold the Heinrich event 3 (HE), 30-31 ka BP, was most likely to be initiated by the global sea level descent and reduction of seawater exchange with the North Pacific. High resolution of δ¹⁸O_pf records reflect a unique sensitivity of the Japan (East) Sea to input of the North Pacific water through the shallow Tsushima and Tsugaru Straits. This led us to the important evidence of the eustatic-sea level changes during the last 40 ka BP. Since 29 ka BP, δ¹⁸O_pf curve shows a continuous descending sea level interrupted by sharp drops of HE 2 at time with a following rise of DO interstadial 2. A sharp δ¹⁸O_pf increase since 18.6 ka BP is consistent with coral results which indicate abrupt termination of LGM lowstand by a rapid sea level rise initiated at 19.0 ka BP.