Large Scale Glacial Erosion and Debris Production

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Although isolated glacial erosion models have been developed, there has been no serious attempt to combine such work with models of glacier flow to provide quantitative insight into larger scale problems of glacial land-form evolution. Moreover, these analyses offer little guidance for a precise treatment of debris production by glacial erosion, and yet debris at the base of glaciers has recently emerged as a central unknown in modern considerations of glacier dynamics. A quantitative model of glacial erosion will be developed based on a fundamental analysis of the physics of glacial abrasion and plucking (quarrying), and field observations at the base of Grinnell Glacier, Montana. Initial theoretical work suggests a physically based relationship between sliding velocity, basal effective pressure and rate of quarrying. Further theoretical work on quarrying, in combination with improvements on Hallet's (1981) abrasion model will provide an overall glacial erosion modelling. This erosion model will be coupled with finite element programs for glacier flow, and used to simulate the development of glacial land-forms such as U-shaped valleys, model spatial patterns of debris production, and tracking debris transport in glaciers and ice sheets.