Artigo Acesso aberto Revisado por pares

Antarctic and Southern Ocean influences on Late Pliocene global cooling

2012; National Academy of Sciences; Volume: 109; Issue: 17 Linguagem: Inglês

10.1073/pnas.1112248109

ISSN

1091-6490

Autores

Robert M. McKay, T. Naish, Lionel Carter, Christina R. Riesselman, Robert B. Dunbar, Charlotte Sjunneskog, D. Winter, Francesca Sangiorgi, Courtney Warren, Mark Pagani, Stefan Schouten, Verónica Willmott, R. H. Levy, Robert M. DeConto, Ross D. Powell,

Tópico(s)

Cryospheric studies and observations

Resumo

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 ∼3.3 Ma, followed by a coastal sea surface temperature cooling of ∼2.5 °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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