THE INFLUENCE OF ICE BURIAL DEPTH ON KETTLE GEOMETRY

Kettles are surficial depressions that commonly form in glaciated terrain as buried, stagnant ice melts within proglacial sediments. Glacial landforms, like kettles, provide insight into the impact of climate on landscape evolution, enabling a more comprehensive understanding of the glacial history of a given physical environment. The geometry of kettle features is variable; however, existing theory does not explain the full range of observed morphologies. Our study aims to establish a quantitative relationship between the depth of ice burial and the resulting angle of terrain collapse in kettle depressions. To do so, we simulate kettle growth in the laboratory by burying ice spheres of various sizes in sand at different depths. As the spheres melt, a depression forms at the surface, analogous to a kettle. We scan the sand surface with a portable LiDAR scanner to produce 3D digital elevation models of the depression, from which we calculate the slope of the collapsed walls. Using this data, we quantify the relationship between the sphere diameter, burial depth, and slope of the kettle walls and scale them to apply to full-scale features. Preliminary results indicate that deeper ice burial corresponds to shallower kettle geometries. Employing these results, we apply our laboratory-derived quantitative relationship to LiDAR data collected from full-scale kettles in Bayfield County, Wisconsin. This application supports our proposed interdependence of ice burial depth and terrain collapse and provides insight into how burial depth affects landscape evolution in the cryosphere.