Abstract:

Core OS031 was retrieved from the southern Okhotsk Sea (150°00′36″E, 49°29′51″N; 975meter water depth). The core consists of 381 m of silty clay and 96 samples were taken. Based on the analysis of AMS 14C ages of planktonic foraminifera, oxygen isotopes of benthic foraminifera, opal content, organic carbon content, planktonic foraminifera assemblage, icerafted debris (IRD) content and grain size distribution of sediments, the research reconstructed the paleoenvironmental records over the past~140 ka. The results reveal that the relative abundance of Neogloboquadrina pachyderma (sinistral) is very good negative correlation with Globigerina bulloides, and both of the two species can be used as the sea paleotemperature proxy compared with the curve of oxygen isotopes. The absolute abundance of the planktonic foraminifera, opal content and organic carbon content show that the climate variation of the study area is obviously affected by glacialinterglacial cycle, and the paleoproductivity in the interglacial period was relatively higher than in the glacial period. The analysis of IRD and sediment grain size indicates that the coarse grain content of the southern Okhotsk Sea in the interglacial period was higher than in the glacial period.

Key words: sedimentary record, planktonic foraminifera；paleoproductivity；icerafted debris；paleotemperature；Okhotsk Sea