Sedimentology and architecture of ice stream beds

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Canada was covered by large ice sheets many times in the last 2.5 million years leaving a diverse heritage of glacial landforms and landscapes which are still not well understood or mapped. The discipline of glacial geology has been re-energized by the finding that ice sheets (modern and ancient) were not slow-flowing domes with steady-state ice flow velocities throughout, but instead contained many fast-flowing ice streams which are corridors of ice as much as 1000 km long and 150 km wide with velocities as high as 10 km a year. This discovery poses new questions about the origins of glaciated landscapes and sediments in North America and elsewhere and has important applied significance yet to be fully evaluated by research on the appropriate ice sheet-wide scale. More than 300 former ice streams within the last Laurentide and Cordilleran ice sheets in North America and in Scandinavia left many millions of streamlined landforms on their beds (drumlins, megascale glacial lineations) composed of either sediment (a soft bed of sediment) or rock (a hard bed e.g., Canadian Shield) or combinations of the two. To date there is no consensus on the origin(s) of these landforms. Detailed mapping is now attainable for the first time, using innovative machine learning techniques developed by the proponent and his group to analyse very large digital data sets (e.g., 35 Tb) of high-resolution imagery such as LiDAR. This reveals hitherto unseen detail that shows that drumlins and MSGLs comprise a bedform continuum and evolve as the ice sheet engineers its bed to lower frictional drag and flow faster. Research will be informed by relevant modelling of how man-made surfaces evolve under friction and by studies of streamlined surfaces on faults and large landslides where analogous bedforms are developed on various scales. At the conclusion of the project we will have accurately mapped ice stream beds  in North America and in Finland at a scale and level of detail hitherto unachievable, and established formative sedimentological models for the evolution and subsurface geology of streamlined bedforms. This information is required by ice sheet modelers, glaciologists working on modern ice streams (where their beds are inaccessible) and the mineral exploration industry requiring information on the erosion and transport of mineralized debris under ice streams, and by groundwater resource managers in densely-populated urban areas in Canada that are built on former beds of paleo-ice streams. The proposed research will generate insights into subglacial processes and debris fluxes below large continental ice sheets and will train highly-qualified students for industry and academia in machine learning and the spatial analysis of high-resolution topographic data sets that are now becoming increasingly available. The long term objective is a new Glacial Map of Canada to replace that which was last completed 50 years ago using low resolution air photographs.