title: Antarctic and Southern Ocean influences on Late Pliocene global cooling.
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 ∼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.
authors.affiliation: Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand. robert.mckay@vuw.ac.nz
authors.forename: Robert
authors.initials: R
authors.lastname: McKay
authors.forename: Tim
authors.initials: T
authors.lastname: Naish
authors.forename: Lionel
authors.initials: L
authors.lastname: Carter
authors.forename: Christina
authors.initials: C
authors.lastname: Riesselman
authors.forename: Robert
authors.initials: R
authors.lastname: Dunbar
authors.forename: Charlotte
authors.initials: C
authors.lastname: Sjunneskog
authors.forename: Diane
authors.initials: D
authors.lastname: Winter
authors.forename: Francesca
authors.initials: F
authors.lastname: Sangiorgi
authors.forename: Courtney
authors.initials: C
authors.lastname: Warren
authors.forename: Mark
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authors.lastname: Pagani
authors.forename: Stefan
authors.initials: S
authors.lastname: Schouten
authors.forename: Veronica
authors.initials: V
authors.lastname: Willmott
authors.forename: Richard
authors.initials: R
authors.lastname: Levy
authors.forename: Robert
authors.initials: R
authors.lastname: DeConto
authors.forename: Ross D
authors.initials: RD
authors.lastname: Powell