Glacial Erosion and the Budget of Basal Rock Debris

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Considerable motivation exists to study processes that govern the abundance and distribution of rock debris at the base of ice masses because they figure importantly in the dynamics and geomorphic manifestations of glaciers and ice sheets. The proposed work is aimed at better understanding how erosional processes operate to generate and modify debris at the glacier bed, and how transport processes mix, disperse and eventually eliminate this debris. Researchers will complete a theoretical model of glacial quarrying and refine a new model of abrasion, which provides for the first time a quantitative link between all major processes governing both the erosion of bedrock and the abundance of basal debris. Then, armed with new model results about quarrying of debris from the bed and particle/bed interactions, it is possible to re-analyse considerable published data on glacial drift, including dispersal patterns, spatial variations in grain size, and particle textures reflecting wear and fracture. The physical insight and quantification gained from the models will shed significant new light on the genesis of glacial debris, and lead to more precise inferences about the behavior of unlithified material at the base of ice sheets and glaciers than has been previously possible. The proposed research is a natural extension of the work nearly completed on large-scale glacial erosion, with funds from ERA87-08400. This study provides a firm foundation for the proposed refinement of our erosion analysis, and its application to the glaciological interpretation of key characteristics of glacial sediments.