Abstract:

A Late Quaternary stratigraphic and chronologic (over the last 100ka) framework is established for Core B2-9 on the slope of the northern Bering Sea, based on correlation of Cycladophora davisiana (radiolarian) content in this core with SPECMAP oxygen isotopic records from deep-sea sediments. Quantitative analytic results of microfossil, charcoal debris and ice-rafted detritus (quartz and lithic grains) in this core indicate that coarse fraction, served as a proxy of surface productivity, increased step by step during the MIS 5.3, reflecting phasic enhanced surface productivity. High abundance of charcoal debris from the MIS 5.3 to deglaciation reveals that the climate in the Bering Sea before deglaciation was drier and colder than that during the Holocene and the occurred natural fire probability heightened much more than that during the Holocene. Ice-rafted detritus (>0.154 mm quartz and lithic grains) increased during the glacial periods and early to middle Holocene indicates that sea ice volume on the shelf of the northern Bering Sea during the periods extended and melted, induced by later warm climate, opening out the Bering Sea responses to past global climate change.