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Patagonian origin of glacial dust deposited in East Antarctica (Vostok and Dome C) during glacial stages 2, 4 and 6

1997; Elsevier BV; Volume: 146; Issue: 3-4 Linguagem: Inglês

10.1016/s0012-821x(96)00255-5

1385-013X

Isabelle Basile, F. Grousset, M. Revel, Jean Robert Petit, Pierre E. Biscaye, Nartssis I. Barkov,

Cryospheric studies and observations

The source area of continental dust deposited at both Vostok and Dome C sites (East Antarctica) during the glacial stages (stage 2: ∼ 18 ka (Last Glacial Maximum), stage 4: ∼ 60 ka and stage 6: ∼ 160 ka) of the last two climatic cycles has remained constant. The isotopic composition (87Sr86Sr and 143Nd144Nd) of the ice-core dust has been compared with the isotopic composition of the potential source areas: Antarctica, New Zealand, Southern Africa, Australia and South America. This comparison reveals the southern South American provenance of the dust for all three glacial periods, as has already been shown for the LGM [1]. We show that the Patagonian loess and the marine shelf sediments from the Argentine continental shelf, which was variably emerged during glacial periods, display different isotopic 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.