Publication Date:
2023-12-13
Description:
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.
Keywords:
Actinocyclus actinochilus; AND1-1B; AND-1B; Chaetoceros spp.; Counting, diatoms; Cycles; DEPTH, sediment/rock; Diatoms indeterminata; DRILL; Drilling/drill rig; Fragilariopsis curta; Fragilariopsis cylindrus; Fragilariopsis kerguelensis; Fragilariopsis obliquecostata; Fragilariopsis ritscheri; Fragilariopsis sublinearis; International Polar Year (2007-2008); IPY; McMurdo Ice Shelf; McMurdo Station; MIS; Porosira pseudodenticulata; Rhizosolenia spp.; Rouxia antarctica; Shionodiscus tetraoestrupii; Stellarima microtrias; Stellarima stellaris; Thalassionema nitzschioides; Thalassiosira antarctica; Thalassiosira lentiginosa; Thalassiosira oliverana; Thalassiosira tumida; Thalassiothrix antarctica; Trichotoxon reinboldii
Type:
Dataset
Format:
text/tab-separated-values, 5851 data points
