SOLUBLE AND BULK GEOCHEMICAL ANALYSIS OF AEOLIAN MATERIAL FROM THE MCMURDO DRY VALLEYS, ANTARCTICA

Aeolian processes play an important role in the transport of both geological and biological materials globally, on the biogeochemistry of ecosystems, and in landscape evolution. As the largest ice free area on the Antarctic continent, the McMurdo Dry Valleys (MDV) are potentially a major source of aeolian material for Antarctica, but little information exists on the spatial and temporal variability of the geochemistry of aeolian materials being transported there. Fifty three samples of aeolian material from Alatna Valley, Victoria Valley, Miers Valley, and Taylor Valley (Taylor Glacier, East Lake Bonney, F6 (Lake Fryxell), and Explorer’s Cove) were collected seasonally at five heights (~ 5, 10, 20, 50, 100 cm) above the surface from 2013 through 2015. The soluble component consisted of varying amounts of the anions Cl^- and HCO3^-, and the major cation was Na⁺ for all sites. Soluble N:P ratios in the aeolian material reflect nutrient limitations seen in MDV soils, where younger, coastal soils are N-limited, while older, up-valley soils are P-limited. Material from East Lake Bonney was N-enriched in the winter samples, but P-enriched in the full year samples, suggesting different sources of material. Analysis of soluble salts from aeolian material in Taylor Valley compared to published soil literature demonstrates a primarily down-valley transport of materials from Taylor Glacier towards the ocean. The mineralogy of the non-water soluble, bulk component was reflective of local rocks, specifically of the McMurdo Volcanics, Ferrar Dolerite, Beacon Sandstone and granite, but variations in major oxide percentages and rare earth element signatures could not be explained entirely by mixing lines between these four rock types. This may suggest an additional, and possibly distant, source of aeolian material to the MDV that is not accounted for. This work provides the first fully elevated spatial and temporal analysis of the geochemistry of aeolian material from the MDV, and aids in the understanding of sediment provenance.