Aeolian dust in East Antarctica (EPICA‐Dome C and Vostok): Provenance during glacial ages over the last 800 kyr

Abstract

International audienceAeolian mineral dust archived in Antarctic ice cores represents a key proxy for Quaternary climate evolution. The longest and most detailed dust and climate sequences from polar ice are provided today by the Vostok and by the EPICA-Dome C (EDC) ice cores. Here we investigate the geographic provenance of dust windborne to East Antarctica during Early and Middle Pleistocene glacial ages using strontium and neodymium isotopes as tracers. The isotopic signature of Antarctic dust points towards a dominant South American origin during Marine Isotopic Stage (MIS) 8, 10, 12, and back to MIS 16 and 20 as deduced from EDC core. Data provide evidence for a persistent overall westerly circulation pattern allowing efficient transfer of dust from South America to the interior of Antarctica over the last 800 kyr. Some small but significant dissimilarity between old and recent glacial ages suggests a slightly reduced Patagonian contribution during ancient glaciations

Centennial-scale variability of the Southern Hemisphere westerly wind belt in the eastern Pacific over the past two millennia

“…Holocene dust sizes measured at these sites are all relatively coarse compared to the ∼ 2 µm modal values measured in the Vostok and EPICA Dome C ice cores from central East Antarctica (e.g., Delmonte et al, 2002). According to a range of geochemical and isotopic evidence, the East Antarctic plateau receives dust primarily from Patagonia, located approximately 6000-7000 km away, although other sources, such as Australia, may contribute during interglacial periods (Basile et al, 1997;Delmonte et al, 2004Delmonte et al, , 2008Revel-Rolland et al, 2006;Marino et al, 2008Marino et al, , 2009. Given the particle size similarities between WAIS Divide and other non-plateau sites, it seems plausible that much of Antarctica has a dust size signature that differs from that of central East Antarctica.…”

Lead isotopic compositions in the EPICA Dome C ice core and Southern Hemisphere Potential Source Areas

“…4 Pb signature of samples containing mostly (>60%) volcanic Pb is consistently radiogenic irrespective of temperature. While glacial-interglacial variations in the composition of Antarctic dust sources have been suggested by Delmonte et al (2008) and Lambert et al (2008), among others, the influence of volcanic Pb during interglacial climate phases inhibits the identification of such variations using Pb isotope signatures.…”

Influence of Patagonian glaciers on Antarctic dust deposition during the last glacial period

“…Antarctic ice cores provide an 800,000 year record of changes in dust flux thought to reflect changes in the vigour of global atmospheric circulation and environmental conditions in source areas [5][6][7][8] . Here for the first time we link the source of Last Glacial dust peaks in Antarctica to the gravel outwash plains of Patagonian glaciers in the Magellan area of southernmost South America.…”