HIGH RESOLUTION MAPPING OF GLACIAL HYDROSTRATIGRAPHY USING LIDAR-BASED HILLSHADE IMAGES, ROTOSONIC CORE, AND GAMMA LOGS
LiDAR-based hillshade imagery was combined with gamma logs to build a detailed three-dimensional depositional model within relatively flat outwash and hummocky collapsed-ice terrain of the ice margin. The 30 meter thick surficial outwash deposits contain cyclic medium to coarse sand intervals of 60 to 100 centimeters in an overall fining upward sequence of coarse to fine sand. High gamma kicks within outwash deposits, correlated to pebbly, matrix supported sandy loams in rotosonic core, are interpreted as debris flows covering areas up to 5,000 square meters. Under the surficial sands, 30 meters of sandy loam tills overlay a six meter thick coarse sand forming a confined aquifer. Hydraulic connectivity can be probed with pumping tests conducted in both the surficial and confined aquifer systems. Correlations of more than one km for the buried tills and the confined aquifer delineate earlier glacial advances below the most recent terminal position of the ice.