Remote-sensing and field-based investigations of Antarctic landscapes: implications for cosmogenic nuclide exposure dating, regional climate change, and science outreach
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A primary goal of Antarctic research is to determine the sensitivity of ice sheets in a warming world. Cosmogenic nuclide exposure-age dating of ancient glacial deposits formed under past climate regimes represents one of the primary approaches used to address this question. Cosmogenic-nuclide dating is typically precise for deposits in non-polar regions, but for previously unknown reasons cosmogenic datasets from Antarctic deposits display significant age scatter and are often at odds with results from other radiometric dating methods, such as 40Ar/39Ar analysis of volcanic ash. In Chapter 1 of this thesis, I examine trends in cosmogenic exposure-age datasets from 93 sites across Antarctica. The results show that although nuclide inheritance impacts all datasets, and may yield scatter in excess of 1 Ma, loss of cosmogenic inventories associated with stochastic rock fractures and "puzzle-rock" development produces most of the wide scatter in Antarctic datasets. This finding shows that the overarching assumption of steady state erosion cannot be applied to analysis of cosmogenic datasets from Antarctica. In Chapter 2, I use Digital Terrain Analysis (DTA) to aid in the detection of new sites for cosmogenic sampling in Antarctica and show how these methods are applicable to detection of glacial landscapes on Mars. In Chapter 3, I extend the application of remote-sensing techniques and introduce a new method for creating DEMs in remote glacial valleys in Antarctica. Finally, in Chapter 4, I summarize how these overall results can be used to engage the wider community in science education, particularly in middle school classrooms.