Exotic aerosols in the Falkland Islands: a record of South American dust and pollen transport to the South Atlantic since 13 ka.

• Main Authors: Hesse, P, Viehberg, F, Schittek, K, Ungrad, L, Hua, Q, White, D
• Format: Conference Object
• Language: English
• Published: The AQUA Biennial Conference. 2019
• Subjects: Glaciers; Aerosols; South American; Dusts; Pollen; Oceans; Patagonia; Southern Ocean; Antarc*; Antarctica
• Online Access: http://apo.ansto.gov.au/dspace/handle/10238/9061; http://aqua.org.au/wp-content/uploads/2013/06/AQUA-2016-program-with-abstracts.pdf

South America is thought to be a major contributor of dust to the Southern Ocean and Antarctica and therefore to affect the hemispheric energy balance and carbon cycle. However, Patagonia is an arid and deflated landscape without any continental records of dust flux. The Falkland Islands, downwind of Patagonia, offer an opportunity to recover such a record from the blanketing peat accumulation.A short peat core taken in 2013 from East Falkland was dated by 14C, analysed by iTrax XRF scanner, LOI and DBD, and pollen analysis. The peat extends back to approximately 13 ka and ceases at around 2 ka (probably due to turf cutting). LOI and iTrax confirm a component of inorganic, siliceous minerals which we infer to be dust transported from South America. The transport of aerosols from South America is confirmed by the presence of exotic pollen (e.g. Araucariaceae), also found by Turney et al. (2016) for the last 2.6 ka. mDust fluxes were high from 13 ka until around 10 ka and remained low except for a brief excursion around 8 ka. A similar pattern was found at a site in the Beagle Channel (Vanneste et al., 2016. Sci Reports), except that at the Falklands the post-ACR/YD decrease in dust flux was delayed by up to 1 kyr. The results support the Patagonian origin of dust to the South Atlantic and suggest a dominantly glacial origin.