Highly resolved East Asian monsoon changes inferred from Sea of Japan sediments

摘要

? 2022The origin and expansion of millennial-scale climate changes in the Earth's climate system, widely presented in different paleo records, remain important issues in the scientific community. In this study, we present a highly resolved record of the East Asian monsoon (EAM) over 123 to 30 ka, obtained from a new archive of millennial/centennial climate variability in the mid-latitudes of the Northern Hemisphere. We used sediments from the semi-enclosed Sea of Japan, which is a region with unique land, ocean, and atmospherice interactions. We obtained color lightness (CL) records of a sediment core recovered from the northwestern part of the Sea of Japan with a high temporal resolution comparable to that of the Chinese EAM records using the original photocolorimeter. The chronology of the studied core was established by correlating the Heinrich events with the measured CL, magnetic susceptibility, and chlorin content with color L* and magnetic susceptibility records of the well-dated Sea of Japan core MD01–2407 and subsequently by correlating the abrupt drops in CL with well-dated Greenland and Chinese interstadials within the established Heinrich events. To infer a new record of EAM evolution, we used the CL record of the studied core over 30–123 ka, when the sea level dropped below the present sea level <90 m, the deep-water ventilation did not change profoundly relative to the present and sediment geochemistry was mainly controlled by millennial-timescale climate changes, such as the Dansgaard–Oeschger (DO) cycles. By comparing the DO cycles inferred from different natural archives, such as δ18O records of Greenland ice core and Chinese caves and CL record of the Sea of Japan sediments, we discussed similarities and some peculiarities of the DO cycles evolution and its millennial scale variabilities recorded in the high, middle, and low latitudes of the Northern Hemisphere over 30–123 ka.