GEOCHEMICAL RECORD OF THE PANAMA BASIN DURING THE LAST GLACIAL MAXIMUM CARBON EVENT SHOWS THAT THE GLACIAL OCEAN WAS NOT SUBOXIC

A geochemical study of sediments associated with the last glacial maxi mum carbon event in the Panama Basin has shown that increased glacial productivity raised the redox boundary closer to the sediment-water in terface, leading to increased storage of U and Mn in the sediments. Ho wever, it seems improbable that the basin became suboxic, and this wou ld suggest that the Mn concentrations were not elevated in the glacial ocean, Fluxes of Th-230 and Pa-231 were higher in glacial times in th e Panama Basin sediments, probably as a consequence of the elevated pr oductivity, but age-corrected Th-230/Pa-231 ratios were higher. This i s consistent with reports of higher particle fluxes external to the ba sin throughout the glacial Pacific Ocean.