Antarctic and Southern Ocean influences on Late Pliocene global cooling
McKay, R.; Naish, T.; Carter, L.; Riesselman, C.; Dunbar, R.; Sjunneskog, C.; Winter, D.; Sangiorgi, F.; Warren, C.; Pagani, M.; Schouten, S.; Willmott, V.; Levy, R.; DeConto , R.M.; Powell, R.D. (2012). Antarctic and Southern Ocean influences on Late Pliocene global cooling. Proc. Natl. Acad. Sci. U.S.A. 109(17): 6423-6428. dx.doi.org/10.1073/pnas.1112248109 In: Proceedings of the National Academy of Sciences of the United States of America. The Academy: Washington, D.C.. ISSN 0027-8424; e-ISSN 1091-6490, more |  |
| Author keywords | glacial history; West Antarctic Ice Sheet; Late Neogene;paleooceanography; paleoclimate |
| Authors | | Top | - McKay, R.
- Naish, T.
- Carter, L.
- Riesselman, C.
- Dunbar, R.
| - Sjunneskog, C.
- Winter, D.
- Sangiorgi, F.
- Warren, C.
- Pagani, M.
| - Schouten, S., more
- Willmott, V.
- Levy, R.
- DeConto, R.M.
- Powell, R.D.
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| Abstract | The influence of Antarctica and the Southern Ocean on Late Pliocene global climate reconstructions has remained ambiguous due to a lack of well-dated Antarctic-proximal, paleoenvironmental records. Here we present ice sheet, sea-surface temperature, and sea ice reconstructions from the ANDRILL AND-1B sediment core recovered from beneath the Ross Ice Shelf. We provide evidence for a major expansion of an ice sheet in the Ross Sea that began at similar to 3.3 Ma, followed by a coastal sea surface temperature cooling of similar to 2.5 degrees C, a stepwise expansion of sea ice, and polynya-style deep mixing in the Ross Sea between 3.3 and 2.5 Ma. The intensification of Antarctic cooling resulted in strengthened westerly winds and invigorated ocean circulation. The associated northward migration of Southern Ocean fronts has been linked with reduced Atlantic Meridional Overturning Circulation by restricting surface water connectivity between the ocean basins, with implications for heat transport to the high latitudes of the North Atlantic. While our results do not exclude low-latitude mechanisms as drivers for Pliocene cooling, they indicate an additional role played by southern high-latitude cooling during development of the bipolar world. |
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