North Pacific response to millennial-scale changes in ocean circulation over the last 60 kyr

Foraminifera-based sea surface temperature estimates in the northwest Pacif ic (Ocean Drilling Program Site 883; 51 degreesN) varied by 4 degreesC on m illennial timescales over the last 60,000 calendar (cal) years, with the mo st prominent amplitudes during marine isotope stage 3. Age control is based on benthic delta O-18 records, C-14 ages, and on geomagnetic intensity var iations at Site 883 tuned to the North Atlantic paleointensity stack since 75 ka (NAPIS-75), in turn, tied to the Greenland Ice Sheet Project 2 (GISP2 ) ice core chronology. On the basis of this tuning, northwest Pacific warm phases parallel Greenland cold stadials and viceversa. This contrasts with atmospheric heat transfer, expected to produce quasi-coeval signals across the Northern Hemisphere. The antiphasing may instead stem from variations i n global thermohaline circulation. At its North Pacific terminus in the sub arctic gyre, any slowdown or shutoff of North Atlantic Deep Water formation during Dansgaard-Oeschger stadials led to a turnoff or reduction of the up welling of cold Pacific deepwater and thus, to striking, instantaneous, sho rt-term warmings of surface water.