A 36 kyr geochemical record from the Sea of Japan of organic matter flux variations and changes in intermediate water oxygen concentrations

Intervals of organic C- and carbonate-rich laminated sediments occur in the Sea of Japan with roughly the same frequency as temperature changes observ ed in Greenland ice cores, providing clear evidence of rapid oceanographic change during the past 36 kyr. Planktonic foraminiferal delta(18)O data sug gest that only the laminated sediments deposited during the Last Glacial Ma ximum (LGM), and perhaps one other interval formed during a period of incre ased water column stratification. Sedimentary Re and Mo data are consistent with bottom waters that were sulfidic during the LGM and suboxic during ot her laminated intervals. Results of a numerical model of C-org and Re buria l are consistent with a mechanism whereby an increased C-org flux to the se afloor drove oxygen concentrations toward depletion during times of deposit ion of the suboxic laminated intervals. Such a process could have resulted from increased upwelling driven either by increased deep water formation du e to colder and/or more saline surface waters or by stronger northeasterly monsoonal winds.