| Content: | Reconstructing climate-related changes in the rate of dust deposition, and in the provenance of the dust, provides critical constraints on hydrology and vegetation in the source regions, as well as on the nature of the atmospheric circulation transporting dust to the archive location.
Ice cores from the East Antarctic Ice Sheet provide an unambiguous record of dust fluxes over the Late Pleistocene. However, less is known about the geographical origin of the terrestrial dust emitted and even less regarding the processes leading to increased dust mobilization.
The aim of this presentation is to present a new extensive geochemical data set characterizing both, potential dust source areas in the Southern hemisphere (South America and Australia) as well as mineral dust deposited at the EPICA Dronning Maud Land (EDML) ice core in Antarctica using helium isotope data, and other trace elements. Among other isotope tracers, we focus on interpreting 4He/Ca ratios, an emerging and promising new provenance proxy. We find a distinct pattern of 4He/Ca ratios between the two regions, with Australia being characterized by relatively high ratios in the range of 10-2 and South American potential dust sources showing lower 4He/Ca ratios, strongly supporting the use of 4He/Ca ratios as a sensitive marker of dust provenance. Measured 4He/Ca ratios at the EDML ice core vary between a few times 10-4 in the Holocene and values in the mid-to high 10-5 during the glacial (Winckler and Fischer, 2006). We will discuss the implications of these results, in the context of current debates to what extent South American and Australian dust sources dominate dust transport to the southern latitudes and the East Antarctic Ice sheet during interglacial climates. |
