PATAGONIAN ORIGIN OF GLACIAL DUST DEPOSITED IN EAST ANTARCTICA (VOSTOK AND DOME-C) DURING GLACIAL STAGE-2, STAGE-4 AND STAGE-6

The source area of continental dust deposited at both Vostok and Dome C sites (East Antarctica) during the glacial stages (stage 2: similar to 18 ka (Last Glacial Maximum), stage 4: similar to 60 ka and stage 6 : similar to 160 ka) of the last two climatic cycles has remained cons tant. The isotopic composition (Sr-87/Sr-86 and Nd-143/Nd-114) of the ice-core dust has been compared with the isotopic composition of the p otential source areas: Antarctica, New Zealand, Southern Africa, Austr alia and South America. This comparison reveals the southern South Ame rican provenance of the dust for all three glacial periods, as has alr eady been shown for the LGM [1], We show that the Patagonian loess and the marine shelf sediments from the Argentine continental shelf, whic h was variably emerged during glacial periods, display different isoto pic compositions and that the composition of the Patagonian loess best matches the signature of the ice-core dust, The identification of the Patagonian region as the source of the windblown dust deposited over East Antarctica during all the latest glacial periods permits a better understanding of paleo-atmospheric circulations of the last climatic cycles and a better constraint on the parametrization of dust sources for paleoatmospheric general circulation models.