A stagnation event in the deep South Atlantic during the last interglacial period.

Hayes CT; Martínez-García A; Hasenfratz AP; Jaccard SL; Hodell DA; Sigman DM; Haug GH; Anderson RF

doi:10.1126/science.1256620

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A stagnation event in the deep South Atlantic during the last interglacial period.

Hayes CT Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA 02142, USA. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA. cthayes@mit.edu.
Martínez-García A Geological Institute, ETH Zürich, 8092 Zürich, Switzerland.
Hasenfratz AP Geological Institute, ETH Zürich, 8092 Zürich, Switzerland.
Jaccard SL Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland.
Hodell DA Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK.
Sigman DM Department of Geosciences, Princeton University, Princeton, NJ 08544, USA.
Haug GH Geological Institute, ETH Zürich, 8092 Zürich, Switzerland.
Anderson RF Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.

2014-12-20

Published in:

Science (New York, N.Y.). - 2014

English During the last interglacial period, global temperatures were ~2°C warmer than at present and sea level was 6 to 8 meters higher. Southern Ocean sediments reveal a spike in authigenic uranium 127,000 years ago, within the last interglacial, reflecting decreased oxygenation of deep water by Antarctic Bottom Water (AABW). Unlike ice age reductions in AABW, the interglacial stagnation event appears decoupled from open ocean conditions and may have resulted from coastal freshening due to mass loss from the Antarctic ice sheet. AABW reduction coincided with increased North Atlantic Deep Water (NADW) formation, and the subsequent reinvigoration in AABW coincided with reduced NADW formation. Thus, alternation of deep water formation between the Antarctic and the North Atlantic, believed to characterize ice ages, apparently also occurs in warm climates.

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