Exploring the role of glaciers on the Southern Hemisphere dust cycle: A Late Pleistocene land-to-ocean perspective – EXODUST

Glaciers play an active role in the high-latitude dust cycle and Earth’s climate by producing huge amounts of silt-sized sediments. However, our current understanding of glaciers and the dust cycle remains limited, although critical in view of the ongoing global ice retreat and associated increase in the exposition of large source areas of dust associated with glaciofluvial sediments. Lessons from the past emerge from the Late Pleistocene, a few tens of thousands of years ago, when continental ice sheets expanded and then melted for the last time. Here we propose to investigate the role of glaciers in the dust cycle by examining, for the first time at millennial timescales, the source-to-sink relationship between the Patagonian Ice Sheet, the major source of glacially-sourced dust to the Southern Hemisphere during the last glacial period, and the dust flux recorded in both Southern Ocean sediments and Antarctica ice. To this end, we will study the timing between Patagonian Ice Sheet fluctuations and the changes in dust flux and provenance in the sub-Antarctic Atlantic using continuous, highly-resolved marine sedimentary records. First, we will improve current understanding of the PIS extent and behavior by tracking regional ice fluctuations through changes in sediment sources at land-proximal core sites using geochemical tracers. Then, we will use the same tracers in the sub-Antarctic Atlantic to track basin-wide changes in South American/Patagonian dust flux and provenance at millennial timescales, and test the source-to-sink connectivity during Patagonian Ice Sheet fluctuations. These reconstructions will bring new light to the causes of millennial-scale variability of Antarctica dust flux, still largely unexplored. In addition to existing studies focusing on the role of wind, precipitation and/or vegetation, this innovative approach will provide an unprecedented dynamic perspective on the high-latitude dust cycle and the role of glaciers.