Multiproxy record of the last interglacial (MIS 5e) off central and northern California, U.S.A., from Ocean Drilling Program sites 1018 and 1020

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Marine microfossil and pollen assemblages, benthic foraminifer δ 1 8 O, physical properties, and calcium carbonate content in sediments from Ocean Drilling Program (ODP) Sites 1018 and 1020 off central and northern California in the eastern North Pacific reveal strong links between the marine and terrestrial environments during marine isotope stage 5 (MIS 5) (∼125,000 years ago). Our multiproxy record indicates that at the beginning of the last interglacial (MIS 5e), reduction in global ice volume, increase in sea-surface temperature, and warming of air temperature along the central and northern California coast were synchronous within the resolution of our sampling interval. The waters off the coast of northern California (near ODP Site 1020) were strongly influenced by warm central Pacific waters at the beginning of MIS 5e near the maximum interglacial. The strong influence of central Pacific waters resulted in less intense upwelling and more zonal atmospheric circulation than exist under modern conditions. Foraminifer assemblages from ODP Site 1018 are generally sparse and poorly preserved, but the assemblages that are present support interpretations based on assemblages from ODP Site 1020. Redwood became most abundant on the west coast of North America after the peak interglacial, presumably as coastal upwelling became more organized or persistent and temperature cooled slightly. Variations in pollen records are similar at ODP Sites 1020 and 1018, indicating that our pollen data reflect regional-scale changes. Variations in physical properties, calcium carbonate content, and diatom assemblages in sediments from ODP Site 1020 appear to be related to changes in the dominance of coastal versus open ocean upwelling. Evidence of upwelling-related cycles of about 8,000 and 5,000 years duration is present throughout much of the MIS 5 record from ODP Site 1020. Two abrupt climatic coolings are identified in MIS 5e, at ∼126 ka and at 119 ka.