MILLENNIAL-SCALE DEEP-WATER OSCILLATIONS - REFLECTIONS OF THE NORTH-ATLANTIC IN THE DEEP PACIFIC FROM 10 TO 60 KA

Northeast Pacific benthic foraminiferal delta(18)O and delta(13)C reve al repeated millennial-scale events of strong deep-sea ventilation (as sociated with nutrient depletion and/or high gas exchange) during stad ial (cool, high ice volume) episodes from 10 to 60 ka, opposite the pa ttern in the deep North Atlantic. Two climate mechanisms may explain t his pattern. North Pacific surface waters, chilled by atmospheric tran smission from a cold North Atlantic and made saltier by reduced freshw ater vapor transports, could have ventilated the deep Pacific from abo ve. Alternatively, faster turnover of Pacific bottom and mid-depth wat ers, driven by Southern Ocean winds, may have compensated for suppress ed North Atlantic Deep Water production during stadial intervals. Duri ng the Younger Dryas event (similar to 11.6-13.0 cal ka), ventilation of the deep NE Pacific (similar to 2700 m) lagged that in the Santa Ba rbara Basin (similar to 450 m) by >500 years, suggesting that the NE P acific was first ventilated at intermediate depth from above and then at greater depth from below. This apparent lag may reflect the adjustm ent time of global thermohaline circulation.