The California Current System as a transmitter of millennial scale climate change on the northeastern Pacific margin from 10 to 50 ka

A high-resolution record of delta O-18 and Mg/Ca-based temperatures spanning 10-50 ka has been reconstructed from the Vancouver margin of the northeastern Pacific Ocean (MD02-2496) from two planktonic foraminiferal species, Neogloboquadrina pachyderma (s.) and Globigerina bulloides. While delta O-18(calcite) appears synchronous with Dansgaard-Oeschger Interstadials throughout the record, millennial scale variability in sea surface temperatures and reconstructed delta O-18(seawater) are frequently out of phase with Greenland climate. Changes in water mass characteristics such as delta O-18(calcite) and enriched delta N-15 events apparently responded to millennial-scale climate change during Marine Isotope Stage 3 (MIS 3), such that negative delta O-18(calcite) excursions coincided with heavier delta N-15. These water mass characteristic shifts are suggestive of the presence of surface water advected from the Eastern Tropical North Pacific by relative strengthening of the California Undercurrent (CUC) bringing warm, salty tropical waters poleward. The linkage between the strength of the CUC on the NE Pacific margin and millennial-scale climate change may be related to increased sea surface heights off Central America as the Intertropical Convergence Zone shifted northward in response to changes in North Atlantic Ocean circulation. Poor correlations between proxies exist through late MIS 3 into MIS 2. Ice sheet growth could have disrupted the linkage between CUC and the NE Pacific margin as the Laurentide Ice sheet disrupted atmospheric circulation and the Cordilleran Ice Sheet increasingly influenced regional paleoceanography.