Reconstructing past ice sheet dynamics and decay from glacial landforms and sediments

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This research program is mainly concerned with understanding the pattern, evolution and controls on ice motion, stability and decay within the ice masses that covered much of Canada and the northern United States during the last ice age. It is important to understand the behaviour of ancient ice sheets because the models developed for their growth, decay, geometry and stability can be used to predict the future behaviour of present-day Arctic and Antarctic ice masses that in turn influence global sea level and climate. Ice motion is, in large part, governed by processes taking place at the glacier bed. The beds of present-day ice sheets are difficult to access, so we turn to the beds of ancient ice sheets (the landforms and sediments that they left behind) to explore the processes that regulate ice dynamics over broad areas, at a variety of scales and perhaps over whole ice ages. Processes taking place at the glacier bed impact ice sheet properties (e.g., thickness, geometry, debris content) and likely have an enduring effect on the rate, style and geometry of ice sheet decay. Research in this application probes the beds of ancient ice sheets, and their landscapes of decay, in order to enhance our understanding of ice motion, stability and decay.    This research will collect new data from ancient glacier bed (subglacial) landforms and sediments in southern British Columbia and Washington State that will contribute significantly to our understanding of the formation of glacial landforms, the evolution of glacial landscapes, and the motion and plumbing of ancient ice sheets. It will provide new decay (deglacial) ages for the Cordilleran ice sheet in southern British Columbia, and may lead to a new model of ice sheet decay that responds to the distribution, extent and drainage of subglacial lakes. The observations and concepts generated by this program are vital to predicting the future behaviour of present-day ice sheets, such as those in Antarctica and Greenland, and will provide critical data for ice sheet models. In addition, the results of this research are anticipated to impact industry in the area of drift prospecting.