| Summary: | Ice-penetrating radar produces detailed images of the internal ice layers in a glacier. Because the layers form from each year's snowfall, the curving of the internal layers is a record of the climate conditions that the glacier experienced as it flowed throughout the millennia. The Hiawatha Glacier lies on top of a meteor crater 30 km in diameter. Airborne radar surveys of the Hiawatha structure show unusually complex internal layering which may be the result of basal freezing and melting, accumulation, or the bedrock topography of the crater. The complexity of basal processes and limited climate data are significant challenges in modeling ice flow. Previous investigations indicated that the slopes of the internal layers alone may be useful indicators of the aforementioned climate boundary conditions. Analyzing the slopes of the layers in two central Hiawatha radargrams, we match distinct signals in the internal layer slopes to particular formation mechanisms. We identify possible signals of basal melt, freezing, frictional changes, and accumulation across the two radargrams. We found only one basal melt signal. We conclude that the layer slope technique is a useful tool to provide qualitative guides to basal friction and melt to aid in ice flow modeling. Key Words: ice-penetrating radar, Hiawatha glacier, Hiawatha crater, Greenland ice sheet, reflector slopes
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