MORPHOLOGICAL MODELS OF GLACIAL LANDFORM EVOLUTION IN THE NORTHERN GREAT PLAINS: A BASIS FOR STUDY OF GROUNDWATER-LAKE INTERACTION

For the Willow Bunch Lake area, Parizek (1961) presented several (at the time) unorthodox approaches to interpret dynamics of glacial sedimentary depositional processes from morphological observations. These produced a genetic classification of glacial lake basins based on locus of impoundment; a classification of meltwater channels, according to drainage parallel or normal to regional slope; an interpretation of the mechanics of contorted bedrock features, based on location of occurrence, bedrock slope, deformational structure, relationship to the morainal sequence and other observations; a catalog of differing types and origins of ice-contact ridges, associated with meltwater channels, outwash plains, and intra-glacial channels; and a catalog of five different classes of ground moraine, mapped across a 150-km square portion of Southern Saskatchewan. The scope and detail of topics may have been limited by the duration of the dissertation (one year) and likely for this reason, there were allusions to but few details regarding the role of groundwater in glacial or post-glacial landscapes. However, subsequent work within this region has revealed a rich variety of kettle lakes within outwash depressions in intimate, complex contact with groundwater. These are formed within outwash trains showing "rise-and-fall" channel gradients, interpreted as subglacial tunnel valleys held open by basal artesian pressures, according to principles described in Parizek (1961). The post-glacial kettle lakes have been largely infilled by postglacial calcareous marl, evolved by groundwater inflow responding to evaporitic climate. A catalog of lakes of the area based on lake water chemistry suggests widely-varying groundwater inflow-outflow ratios, supporting rich diversity in hydraulic interconnection between lakes and outwash. Conceptual models in the Parizek style may be developed relating lake-groundwater interaction to the nature of ice-contact and ice-collapse deposits. At least two unique ultra-deep (25-40 meters, based on coring investigations) meter ice-contact depressions have been identified within outwash trains, that contain a rich paleoclimatic record in the form of groundwater-source authigenic precipitates. Work on these features is ongoing.