Multiple-cosmogenic-nuclide approaches to studying the Holocene and late Pleistocene history of small ice caps in western Greenland
This thesis contains two chapters; one dealing with long-term landscape evolution and late Quaternary ice sheet history along the western margin of the Greenland Ice Sheet (GIS), and the other with assessing the sensitivity of exposure durations calculated from paired bedrock 14 C/10Be measurements in glacial troughs. Both chapters were designed to improve our understanding of the glacial history of Greenland. The objective of the first chapter was to investigate differences in the late Quaternary glacial history between two landscapes of differing characteristics along the western margin of the GIS. Paired in situ cosmogenic 10Be and 26Al measurements suggest that surfaces surrounding the marine-terminating setting of Uummannaq have been continuously exposed for much of the latter Quaternary, and surfaces in the more terrestrial Sukkertoppen region were largely buried beneath non-erosive, cold-based ice during the same period. Results from the Uummannaq region are unique for many Arctic landscapes surrounding Baffin Bay. The objective of the second chapter was to explore the isochron technique of Goehring et al., (2013) by testing the sensitivity of exposure durations to both the number of samples analyzed and their spatial distribution along a cross-trough transect. Results indicate that five or more samples evenly distributed along a cross-trough transect are adequate for this method, and that as few as three samples may provide accurate exposure duration estimates, particularly from lateral locations in a glacial trough.
Lifton, Purdue University.
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