Late Holocene dust provenance at Siple Dome, Antarctica. (15th December 2021)

• Record Type: Journal Article
• Authors: Koffman, Bess G.; Goldstein, Steven L.; Winckler, Gisela; Kaplan, Michael R.; Kreutz, Karl J.; Bolge, Louise; Bory, Aloys; Biscaye, Pierre
• Is Part Of: Quaternary science reviews. Volume 274(2021)
• Publication Date: 2021-12-15
• Subjects: Antarctica -- Dust provenance -- Sr–Nd isotopes -- Ice cores -- Southern ocean -- Gaussberg volcano; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2021.107271
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: Compositions of mineral dust in ice cores serve as tracers of paleo-atmospheric circulation patterns, providing linkages between sources and sinks. Here we document the geochemical makeup of dust reaching continental West Antarctica, on late Holocene samples from the Siple Dome A ice core (spanning ∼1030–1800 C.E). The Nd–Sr isotope signature is unusual for Antarctic ice core dust samples. Siple Dome data are characterized by low Nd isotope ratios (as low as εNd = −16.3) along with low Sr isotope ratios (highest 87 Sr/ 86 Sr = 0.7102) compared with other Antarctic dust signatures. A well-defined inverse correlation between Sr–Nd isotope ratios indicates two primary mixing sources. The low εNd-values indicate involvement of ancient (Archean-to-early Proterozoic) continental crust, as either the direct source or as a precursor of the source, and the low Sr-values require low Rb/Sr ratios that often reflect high-grade metamorphism. The known Antarctic terrane with these characteristics is parts of Enderby Land, nearly at the opposite end of Antarctica. The isotopic signature of the second end-member is compatible with West Antarctic volcanoes or Patagonia in South America. The Sr–Nd isotopes and trace element abundances are also chemically compatible with mixing between volcanic material from Gaussberg, a small lamproite volcano in Kaiser Wilhelm II Land in coastal East Antarctica whose source is ancient lithospheric mantle, with dust from Patagonia or material from West Antarctic volcanoes. We assess these potential mixing scenarios and conclude that Siple Dome's unusual geochemical signature can best be explained by a mixture of Patagonian dust and a Gaussberg-like source, with additional minor contributions from old eroded Archean-to-early Proterozoic bedrock sources such as those in Enderby Land. Moreover, Siple Dome dust compositions are distinct from dust deposited on Taylor and Clark Glaciers in the McMurdo Dry Valleys of the western Ross Sea, precluding the Dry Valleys as a late Holocene dust source to this region of the eastern Ross Sea. Highlights: Sr and Nd isotope ratios and rare earth elements used to infer dust provenance. Extremely low Nd isotope ratios indicate Archean to early Proterozoic source. Potential contributions of dust from Gaussberg, a lamproite volcano. Dry Valleys, Australia, New Zealand are not sources of dust to Siple Dome.