Geomorphology of the Great Lakes Lowlands of Eastern Canada

Abstract

The Great Lakes Lowlands is Canada’s most populated region. While landform distributions are mainly related to a legacy of Quaternary glaciation and pre-Quaternary bedrock erosion, many modern processes of sediment erosion and deposition are significantly influenced by human modifications to the landscape, including deforestation, agriculture, aggregate extraction and urbanization. Ice lobes and/or streams of the Laurentide Ice Sheet Complex have resulted in a complex arrangement of ice-contact, ice-marginal and pro-glacial sediment sequences infilling pre-glacial bedrock channels. End moraines and interlobate kame moraines are thick and their spatial arrangement records multiple ice-flow directions around the eroded Great Lakes. The “peninsula” of southern Ontario undergoes significant coastal modifications as wave energy from three of the lakes erodes and redistributes glacilacustrine and glacifluvial sediments along shorelines. Post-glacial isostatic uplift has resulted in entrenchment of both subsequent and consequent river systems exposing mixed channel boundaries of glacial sediments and bedrock. Modern infrastructure has developed on these surfaces that are still undergoing post-glacial adjustment.