A revised look at Canada's landscape: glacial processes and dynamics

Our understanding of the Laurentide Ice Sheet has been significantly improved by recent developments in theoretical models of ice sheets and ice dynamics, understanding of mechanisms of glacial erosion, transport and deposition, and mapping of glacial depositsand drift composition. Theoretical models have increasingly accommodated diverse glaciological, physiographic and geological factors that can affect ice flow, and have been used to reinterpret the geological record in terms of glacial processes. The glacial system of North America is described atscales from continental (thousands of square kilometres), to regional (hundreds of square kilometres), local (kilometres to tens of kilometres), and site-specific (hundreds of metres to kilometres). Drift prospecting is based on an understanding that indicators of economic mineralization recoveredfrom glacial deposits can be traced back to their original bedrock source. Geochemical, mineralogical and lithological methods employed in the exploration for mineral deposits in glaciated terrain requires knowledge of past glacial flow direction(s), means of entrainment, and variations in thenature of glacial dispersal such as glacial sediment thickness, bedrock topography, bedrock erodibility, and basal glacial flow velocity gradient. Combined, this knowledge is used to determine the distance to the up-ice bedrock source from the identified down-ice dispersal train location. Over thelast two decades, drift prospecting in northern Canada has significantly improved through the continued development of ice sheets models, and the acquisition of empirical evidence for ice-flow patterns, drift composition and glacial history. Increased attention to the dynamic nature of glacialdispersal centers and related ice-flow complexes has thus become increasingly important for mineral exploration in northern Canada.