Periglacial Landscape Evolution in Antarctica: New Constraints on Patterned Ground Formation

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The proposal seeks limited funds to exploit fully the samples and data collected during the 2007/2008 field season in Dry Valleys, Antarctica. The landscapes of the Dry Valleys region are among the oldest on Earth, some as old as Miocene, ~15 million years old. Although these inferred ages are relevant to the long-term stability of the East Antarctic Ice Sheet; the specific mechanisms and rates of landscape modification are not well constrained. Cryoturbation (most commonly recognized as patterned ground) is one of the primary landscape modifiers in periglacial environments. This project's effort will be focused to direct determination of cryoturbation rates and mechanisms using a combination of geochronology of field samples combined with the LiDAR landscape characterization. The cosmogenic 3He measurements will be completed on the depth profiles and surficial samples from Beacon Valley and Mount Morning. While the emphasis will be on 3He measurements as they can be done more quickly, the 21Ne measurements will be also undertaken on selected samples. The cosmogenic nuclide measurements are the most labor-intensive component of the proposed project.