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Mineral dust aerosols represent an active component of the Earth’s climate system, by interacting with radiation directly, and by modifying clouds and biogeochemistry. Mineral dust from polar ice cores over the last million years can be used as paleoclimate proxy, and provide unique information about climate variability, as changes in dust deposition at the core sites can be due to changes in sources, transport and/or deposition locally. Here we present results from a study based on climate model simulations using the Community Climate System Model. The focus of this work is to analyze simulated differences in the dust concentration, size distribution and sources in current climate conditions and during the Last Glacial Maximum at specific ice core locations in Antarctica, and compare with available paleodata. Model results suggest that South America is the most important source for dust deposited in Antarctica in current climate, but Australia is also a major contributor and there is spatial variability in the relative importance of the major dust sources. During the Last Glacial Maximum the dominant source in the model was South America, because of the increased activity of glaciogenic dust sources in Southern Patagonia-Tierra del Fuego and the Southernmost Pampas regions, as well as an increase in transport efficiency southward. Dust emitted from the Southern Hemisphere dust source areas usually follow zonal patterns, but southward flow towards Antarctica is located in specific areas characterized by southward displacement of air masses. Observations and model results consistently suggest a spatially variable shift in dust particle sizes. This is due to a combination of relatively reduced en route wet removal favouring a generalized shift towards smaller particles, and on the other hand to an enhanced relative contribution of dry coarse particle deposition in the Last Glacial Maximum.

Insoluble dust concentrations and volume-size distributions have been measured for the new 581 m deep Dome C-EPICA ice core (Antarctica). Over the 27000 years spanned by the record, microparticle measurements from 169 levels, to date, confirm evidence of the drastic decrease in bulk concentration from the Last Glacial Maximum (LGM) to the Holocene (interglacial) by a factor of more than 50 in absolute value and of about 26 in flux. Unique new features revealed by the EPICA profile include a higher dust concentration during the Antarctic Cold Reversal phase (ACR) by a factor of 2 with respect to the Holocene average. This event is followed by a well-marked minimum that appears to be concomitant with the methane peak that marks the end of the Younger Dryas in the Northern Hemisphere. Particle volume-size distributions show a mode close to 2 μm in diameter, with a slight increase from the LGM to the Holocene; the LGM/Holocene concentration ratio appears to be dependent on particle size and for diameters from 2 to 5 μm it changes from 50 to 6. Glacial samples are characterised by well-sorted particles and very uniform distributions, while the interglacial samples display a high degree of variability and dispersion. This suggests that different modes of transport prevailed during the two climatic periods with easier penetration of air masses into Antarctica in the Holocene than during Glacial times. Assuming that southern South America remained the main dust source for East Antarctica over the time period studied, the higher dust content recorded during the ACR which preceded the Younger Dryas period, represents evidence of a change in South America environmental conditions at this time. A wet period and likely mild climate in South America is suggested at circa 11.5–11.7 kyr BP corresponding to the end of the Younger Dryas. The Holocene part of the profile also shows a slight general decrease in concentration, but with increasingly large particles that may reflect gradual changes at the source.