SIMILAR RATES OF MODERN AND LAST-GLACIAL OCEAN THERMOHALINE CIRCULATION INFERRED FROM RADIOCHEMICAL DATA

Today, the ocean thermohaline circulation transports half of the Pa-23 1 produced by radioactive decay in the Atlantic Ocean water column to the Southern Ocean. This export respectively imparts low and high Pa-2 31/Th-230 ratios to the surface sediments of these oceans. Ocean sedim ents from the Last Glacial Maximum bear a similar isotopic fingerprint , implying that advection of North Atlantic Deep/Intermediate Water in to the Circumpolar Deep Water of the Southern Ocean occurred at a simi lar-or slightly higher-rate during the last glacial period.