Continental glaciers originating at both poles reached their farthest extent about 20,000 years ago, marking a time known as the Last Glacial Maximum.
Comparisons of ice cores from Greenland and Antarctica show that as these glaciers melted, warming occurred in asynchronous stages at the poles. While many northern hemisphere climate records match ice core records from Greenland, few southern hemisphere records exist to compare with ice core data from Antarctica.
Calvo et al. analyze a marine core collected off South Australia and find that it contains detailed signatures of surface temperatures of waters that washed over it since the glacial maximum.
Data from this core match well with Antarctic ice cores and paleoclimate records from the Australian continent, showing no signature of the Younger Dryas, a cooling event known to have occurred in the Northern Hemisphere about 13,000 years ago.
The new core data also reveal a progressive drop in sea surface temperatures over the last 6,500 years, an observation not seen before for the Australian region.
Title: Antarctic deglacial pattern in a 30 kyr record of sea surface temperature offshore South Australia
Authors: Eva Calvo: Institut de Ciències den Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain;
Carles Pelejero: Institució Catalana de Recerca i Estudis Avançats and Institut de Ciències den Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain;
Patrick De Deckker: Department of Earth and Marine Sciences, The Australian National University, Canberra, Australia;
Graham A. Logan: Petroleum and Marine Division, Geoscience Australia, Canberra, Australia.
Source: Geophysical Research Letters (GRL) paper 10.1029/2007GL029937, 2007
Materials provided by American Geophysical Union. Note: Content may be edited for style and length.
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