HR: 08:35h
AN: PP31E-03    [Abstracts]
TI: Dust Provenance in Antarctic ice During Glacial Periods: Calibrating the Dust Emission Record of Southern South America.
AU: * Gaiero, D M
EM: dgaiero@efn.uncor.edu
AF: CIGeS/CICTERRA/CONICET/Universidad Nacional de Córdoba, Avda. Vélez Sársfield 1611, Córdoba, Cba x5016cga, Argentina
AB: Much of the researches dedicated to study the provenance of sediments in Antarctica ice cores and sediment cores in the ocean promoted not-too-convincing conclusions in some of their interpretations, mainly due to unawareness on the actual composition of sediments derived from Patagonia and important source areas of southern South America (SSA). Most of the latest works [e.g. EPICA community members, 2006; Fischer et al., 2007] that attempted to model and understand the increase of dust deposition in Antarctic ice during last glacial periods used Patagonia as the most obvious provenance area. However, it was indicated recently that Patagonia could only explain the composition of a few Antarctic dust samples [Gaiero et al., 2007a], which implied that other dust sources should be taken into account in order to improve atmospheric circulation models and to better understand the changes in source areas during glacial periods. This work mainly focuses on the origin of those Antarctic dust samples that do not have a Patagonian signature. This is made by using isotopic composition of sediments from different southern latitude environments; i.e., exploring the role played by the Argentinean shelf and the Argentinean loess as possible direct sources of this non-Patagonian signature [Gaiero, 2007b]. The study concludes that both areas should not be considered as significant dust sources during glacial times highlighting, however, the importance of the Argentinean loess to understand the sources that contributed to its accumulation and hence, to understand the long-range dust transport in the Southern Hemisphere. Based on isotopic data and on environmental characteristics it is demonstrated that along Patagonia, the Puna-Altiplano plateau (10S-26S) should be an extra important subtropical dust source. EPICA Community Membres (2006), One-to-one coupling of glacial climate variability in Greenland and Antarctica. Nature, 444, 195-198. Fischer H., et al. (2007), Reconstruction of millennial changes in dust emission, transport and regional sea ice coverage using the deep EPICA ice cores from tha Atlantic and Indian Ocean sector of Antarctica, Earth and Planet. Sci. Lett., 260, 340-354. Gaiero, D.M., et al. (2007a), A uniform isotopic and chemical signature of dust exported from Patagonia: Rock sources and occurrence in southern environments, Chem. Geol. 238, 107-120. Gaiero, D.M. (2007b), Dust Provenance In Antarctic Ice During Glacial Periods: from where in the Southern Hemisphere? Geophys. Res. Lett. (doi 10.10292007GL030520).
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 1040 Radiogenic isotope geochemistry
DE: 3319 General circulation (1223)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4801 Aerosols (0305, 4906)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting