Major Oxide Chemistry of Mineral Dust, McMurdo Dry Valleys, Antarctica: Revisited

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Major Oxide Chemistry of Mineral Dust, McMurdo Dry Valleys, Antarctica: Revisited

Melisa A. Diaz, W. Berry Lyons, Byron J. Adams, Susan A. Welch, Alia L. Khan, Diane M. McKnight, S. Craig Cary

At the 2014 DUST meeting some of the first geochemical data of aeolian materials from the McMurdo Dry Valleys (MDV), Antarctica were presented. The MDV is the largest ice-free area in Antarctica, and the transport and deposition of windblown materials are thought to play an important role in landscape connectivity, which in turn has important ecological consequences. The previous work was on samples collected only 30cm off the ground and probably represents material transported primarily by saltation. In this study, we have collected samples at multiple heights, including at 100cm above the ground surface. Samples were collected during two different periods during 2013–2015. Bulk samples were analyzed by XRF techniques for major oxides. The CIAs of the aeolian material indicate little chemical weathering, and the values varied little with respect to height above the surface. The least weathered material comes from the highest elevation valleys, where liquid water is thought to be less available for chemical weathering to occur. These data are similar to those reported for the original, 30cm height samples, and are most similar to the local Ferrar Dolerite. Additionally, Al2O3:TiO3 values indicate differences in the weathering of available materials spatially, particularly with height above the surface. These data indicate multiple terrestrial sources contributing to the geochemistry of aeolian material, even in cold and arid environments.

Keywords: Antarctica, McMurdo Dry Valleys, Bulk geochemistry, Chemical weathering

Proscience vol. 5

Pp 25-30