Antarctic and Southern Ocean influences on Late Pliocene global cooling

作者：McKay Robert^*; Naish Tim; Carter Lionel; Riesselman Christina; Dunbar Robert; Sjunneskog Charlotte; Winter Diane; Sangiorgi Francesca; Warren Courtney; Pagani Mark; Schouten Stefan; Willmott Veronica; Levy Richard; DeConto Robert; Powell Ross D

来源：Proceedings of the National Academy of Sciences, 2012, 109(17): 6423-6428.

DOI：10.1073/pnas.1112248109

• glacial history
• West Antarctic Ice Sheet
• Late Neogene
• paleooceanography
• paleoclimate

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.

• 出版日期2012-4-24