Sedimentology of tunnel valley deposits

点击翻译按钮获取中文摘要

The urbanized regions of Canada are rapidly expanding and there is a growing need to locate, manage and protect sources of drinking water, particularly from groundwater reservoirs (aquifers). However, a major problem facing hydrogeologists trying to locate new sources of groundwater is determining the size and location of units of permeable sediments that host groundwater resources (aquifers) in thick successions of glacial sediment. Recent investigations have shown that many groundwater aquifers are hosted in permeable sediments deposited in large channels (tunnel valleys) that developed beneath the ice sheets that covered northern North America approximately 20,000 years ago. Unfortunately, there is limited understanding of the nature of the sediments infilling these tunnel valleys or their origin. In this proposal I seek funding to investigate the characteristics of tunnel valley sediments in Alaska and Southern Ontario with the aim of better understanding their sedimentological record and evolution. Enhanced understanding of the sedimentology of tunnel valley deposits is essential for future groundwater exploration and management in Canada. The proposed research will investigate the infills of tunnel valleys in two settings: the coastal region of Alaska where the late Cenozoic Yakataga Formation is well exposed, and in southern Ontario where surface exposures and borehole data through Pleistocene tunnel valley deposits are available. These sites were chosen because both locations provide exceptional, and accessible, exposures through tunnel valley deposits on extensive wave cut platforms and in vertical cliff sections on a scale unmatched anywhere in the world. Research will be conducted using an innovative landsystems' approach that integrates examination of glacial landforms with the sediments underlying them. The research proposed here involves initial identification and mapping of tunnel valley features at sites in Alaska and Southern Ontario from satellite imagery; these maps will then guide field investigations of landforms and outcrops using standard sedimentological techniques that document grain size, sedimentary structures, and unit geometries. We will also use an unmanned aerial vehicle (UAV/drone) to collect high resolution imagery of sediment exposed on wave cut platforms and in cliff exposures. All of these data will be used to develop new depositional models for tunnel valley systems that will enhance the prediction of groundwater movement in these deposits. This research will greatly benefit Canada by enhancing our understanding of glacial sediments and their influence on the movement of groundwater, and will aid in the exploration for, and management of, groundwater resources. This research will also involve the training of at least 6 new graduate HQP's and 10 undergraduates and is significant given the anticipated shortage of skilled professional geoscientists in Canada.