Orbital and millennial-scale environmental and sedimentological changes in the Okhotsk Sea during the last 350 kyr

摘要

The chlorine content (CC), magnetic susceptibility, water content, density and coarse sediment fraction (CF/ IRD) of an Okhotsk Sea sediment core PC-7R have been measured for the last 350 kyr. The PC-7R age model was constructed by matching the dated series of relative paleointensity lows recognized in geomagnetic intensity records, marine isotope stages (MIS) determined in the lithophysical proxies, CC and color reflectance b* variability and tephrochronology. The orbital changes of the OS lithophysical proxy D, WC and CF (IRD) lag behind Northern Hemispheric summer radiation around 6-12 kyr consistently with M. Milankovich's view of climate control by solar radiation through the northern ice sheets volume. On the basis of inphasing of the millennial-scale climate cycles in the North Hemisphere for last 75 kyr, we suggest that some 48 pronounced cold events observed in the OS records during MIS 2-10 are Heinrich-equivalent event anomalies, which have counterparts in climate records of the North Atlantic, Greenland and East Asian.