Rapid climate oscillations in the Northeast Pacific during the last deglaciation reflection Northern and Southern Hemisphere sources

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doi: 10.1029/GM112p0127
Author(s): Mix, Alan C.; Lund, David C.; Pisias, Nicklas G.; Boden, Per; Bornmalm, Lennart; Lyle, Mitch; Pike, Jennifer
Author Affiliation(s): Primary:
Oregon State University, College of Oceanic and Atmospheric Sciences, Corvallis, OR, United States
Oregon State University, United States
Woods Hole Oceanographic Institution, United States
Harvard University, United States
Stockholm University, Sweden
Boise State University, United States
University of Cardiff, United Kingdom
Volume Title: Mechanisms of global climate change at millennial time scales
Volume Author(s): Clark, Peter U., editor; Webb, Robert S.; Keigwin, Lloyd D.
Source: Mechanisms of global climate change at millennial time scales, edited by Peter U. Clark, Robert S. Webb and Lloyd D. Keigwin. Geophysical Monograph, Vol.112, p.127-148. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0065-8448. ISBN: 978-1-118-66474-2 CODEN: GPMGAD
Note: In English with English summary. 93 refs.; illus., incl. 2 tables, sketch map
Summary: Planktic foraminiferal species abundances, benthic and planktic foraminiferal stable isotopes, radiocarbon, and organic carbon contents of deep-sea cores off Oregon and Northern California reveal abrupt millennial-scale climate oscillations during the past 20,000 years. Changes in the near-surface ocean are essentially coincident with the Bolling-Allerod and Younger-Dryas climate oscillations observed in Greenland ice cores and North Atlantic sediments. This finding supports the concept of atmospheric transmission of climate signals between oceans within the Northern Hemisphere. Abrupt cooling of North Pacific surface waters occurred in mid-Holocene time, indicating that the warm events of the early Holocene and deglaciation are anomalous relative to modern climate. Higher export productivity is associated with warm events in the North Pacific. These biotic changes may have contributed to variations in the shallow (∼400 m depth) oxygen minimum zone off California, and may in part explain the apparent coincidence of local anoxia with warming in Greenland. Benthic foraminiferal δ13C and 14C data from lower intermediate waters (980 m depth) suggests that higher ventilation (either faster formation or greater gas exchange) occurred during the Bolling-Allerod and early Holocene warm events. Synchronicity with surface ocean changes points to North Pacific source waters, and ventilation during warming leads to a hypothesis that salinity rather than temperature controls intermediate water formation at these times. In the deep North Pacific (2700 m depth) benthic foraminiferal δ18O changes imply early warming roughly synchronous with warming of the Southern Ocean. Both δ13C and 14C suggest an abyssal ventilation event (either faster formation or greater gas exchange) during deglaciation at the same time as short-term cooling in Antarctica, pointing to a Southern Ocean source of variability in the deep Pacific. Thus, climate changes that characterize both northern and southern sources appear to propagate through the Pacific Ocean.
Year of Publication: 1999
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Antarctic Ocean; Antarctica; Arctic region; Benthic taxa; C-13/C-12; C-14; California; Carbon; Cenozoic; Climate effects; Currents; Deglaciation; East Pacific; Foraminifera; Glacial geology; Glaciation; Greenland; Ice cores; Invertebrata; Isotope ratios; Isotopes; Leg 167; Microfossils; North Pacific; Northeast Pacific; Northern California; O-18/O-16; ODP Site 1019; Ocean Drilling Program; Ocean currents; Oscillations; Oxygen; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleocurrents; Pleistocene; Protista; Quaternary; Radioactive isotopes; Stable isotopes; United States; Upper Pleistocene; Upper Weichselian; Weichselian; Younger Dryas
Coordinates: N414058 N414058 W1245559 W1245559
Record ID: 2000062619
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.