Trace Element Proxies of Carbon Flux and Bottom Water Oxygen Concentration

9314634 ANDERSON Uranium is removed from the ocean by precipitation in chemically- reducing sediments. Preliminary results from subantarctic South Atlantic show high rates of authigenic U deposition in glacial-age sediments. The observed burial of uranium implies that one of two conditions existed in the glacial ocean: either greatly-reduced oxygen content of Circumpolar Deep Water (compared to modern levels in excess of 200 micromolar), or greatly-enhanced biological productivity of subantarctic surface waters. Either condition would represent a significant feature of the carbon cycle in the glacial ocean. The hypothesis that subantarctic sediments hold the key record which will lead to the long-sought explanation for lower atmospheric CO2 concentrations during the ice ages will be tested to also derive quantitative information about ice-age ocean productivity and deep-sea 02 content.