A glaciofluvial origin for drumlins of the Livingstone Lake area, Saskatchewan

Abstract

The Livingstone Lake drumlin field of northern Saskatchewan is on the Athabasca Plains. It is draped over high ground underlain by the Precambrian Athabasca Sandstone. The drumlins occur in spindle, parabolic, and transverse asymmetrical forms. A map of individual drumlins shows that features of similar form occur together. The drumlins are related on a regional scale to even larger landforms. There is also an arrangement of drumlins in streams parallel to the assumed flow direction. These patterns illustrate spatial organisation of the drumlin-forming flows. The Livingstone Lake drumlins are closely related to tunnel valleys, large crescentic scours, and eskers. Exposed bedrock reveals widespread scalloping and sichelwannen. An argument is made that drumlins are related to these glaciofluvial forms but were created at different times and by different flows than those forming small-scale flutings and other lodgment features. Sediments within the drumlins are mainly primary water-sorted deposits some of which were resedimented by mass movements. There are also large, striated boulders. Deposition in subglacial cavities is suggested. This explanation is supported by a comparison of patterns and forms of erosional marks produced by wind and water and the implied form of the subglacial cavities. The Livingstone Lake drumlins are considered to represent infillings of cavities developed by meltwater erosion of the underside of glaciers. This conclusion stresses the geomorphic and sedimentologic importance of subglacial meltwater. It has important implications for the behaviour of the large Pleistocene ice sheets and the interpretation of glacigenic sediments. Consequently, it has direct bearing on glacial stratigraphy and chronology.