Deep sea ventilation of the northeastern Atlantic during the last 15,000 years

Sea surface temperature and salinity estimates reconstructed from a core (56/-10/36) collected on the Barra Fan, northwest Scotland (56°43′N, 09°19′W; water depth 1320 m) show a series of rapid oscillations during the last deglacial period that are very similar to those observed in the δ18O records from Greenland ice cores. These records indicate that the transport of heat and salt toward the Nordic Seas was highest during the Bølling period. A nearby deeper water core (57/-11/59) on the distal margin of the Barra Fan (57°01′N, 10°01′W, water depth 2089 m) allows us to study the response of the δ13C record of the benthic foraminifera Cibicidoides wuellerstorfi through the deglacial interval at a century/decadal scale. By comparing the sea surface temperature, salinity and benthic records at this site with other Atlantic Ocean records, we evaluate the timing of deep sea ventilation with changes in surface water characteristics. The benthic δ13C evidence suggests that NADW formation strengthened during the Bølling–Allerød period and ventilation was at least as strong as it has been for much of the Holocene. Maximum deep water formation was essentially coincident with the maximum northward transport of heat and salt, but predates the transition in δ13C which is recorded in the deep western Atlantic. Deep water ventilation of this site was reduced during the Younger Dryas period.