Abstract

Multiproxy data from North Atlantic deep-sea sediment core NEAP18K provide a detailed record of climate through oxygen isotope stage (OIS) 5. Seven distinct, large-scale episodes of ice rafting (C25–C19) were identified between 126 and 70 ka. Global ice-volume reconstructions, based on high-resolution benthic δ18O records, indicate that major ice-rafting events were not confined to ice-volume maxima at OIS 5d and 5b, but also occurred during periods of ice-sheet growth and disintegration. However, iceberg discharges were restricted to times when sea levels were 40–65 m below present values. Ice-rafting episode C25, the first large-scale cooling of mid-Atlantic surface waters after the last interglacial, occurred during the gradual buildup of continental ice sheets at the OIS 5e-5d transition. Major ice-sheet collapses allied to ice-rafting events C24 and C21 were associated with rapid sea-level increases of 20 and 40 m, respectively. Suborbital climatic fluctuations in the NEAP18K sedimentary record, denoted by prominent 7.5, 4.5, and 3 k.y. cyclicities, appear to correlate with both Greenland atmospheric temperatures and changes in thermohaline circulation patterns, inferred from benthic δ13C values, and hence provide clear evidence of a highly interconnected North Atlantic climatic regime during OIS 5.

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