DIFFERENTIATING SAGINAW FROM HURON-ERIE ICE LOBE MELTWATER DEPOSITS IN SOUTH CENTRAL MICHIGAN USING LONGITUDINAL PROFILES, GRAIN SIZE ANALYSIS, AND LITHOLOGY

The Saginaw and Huron-Erie lobes of the Laurentide Ice Sheet had a significant impact on the landscape of south-central Michigan after the Late Glacial Maximum. During the advances and retreats of these lobes, a complicated network of meltwater channels developed. Two goals of this study are: 1) to use sand-grain lithology, grain-size analysis, and longitudinal profiles to determine if a difference exists between Saginaw Lobe and Huron-Erie Lobe meltwater deposits 2) to determine if a large meltwater sluiceway containing the modern St. Joseph River had a source of meltwater and outwash from the Huron-Erie Lobe. Two cores from drumlinized uplands formed by the Saginaw lobe were compared to three cores from the St. Joseph sluiceway that, based on longitudinal profiles, carried meltwater from the Huron-Erie lobe. Grain-size and sand-grain lithology analysis were conducted on these five cores. The sand-grain lithology analysis indicates a significant difference in shale content between the cores within the channelized lowland and the drumlinized uplands. Increased shale content within the channelized lowlands is likely derived from Paleozoic shales within the flow path of the Huron-Erie lobe (Coldwater, Antrim, Sunbury, Bedford shales). Longitudinal profiles and mapping of the channelized lowlands show a gentle gradient from east to west indicating a meltwater source of the Huron-Erie lobe.