The Lake Effect: Lake Michigan, Landscape Evolution, and the Archaeological Record of the Chicago Region

Abstract

Abstract Lake Michigan continues to have a major impact on the environment in the Chicago region, and changes in lake levels were a major driver of landscape evolution throughout the late Pleistocene and Holocene. Fluctuating lake levels reduced or increased the extent and character of terrestrial resources. The landscape has also been altered by erosional and aggradational processes from near-shore currents and wave action. Interpretation of archaeological site and settlement patterns in this region requires an understanding of the factors that have shaped and continue to shape this landscape. In the PaleoIndigenous and Archaic periods, foraging groups adapted to rapidly changing vegetation patterns and episodes of lake transgression and recession that opened or closed new habitats. In the Woodland and Upper Mississippian periods, lake levels stabilized, but the landscape continued to evolve, with erosion and deposition of sediments along Lake Michigan shorelines. Evidence for lake-level fluctuations over the last 12,000 years is available from a variety of data sets, including those for deep lacustrine sediments, ostracods, abandoned shorelines, and sand dunes. By synthesizing these data and utilizing GIS to reconstruct past lakeshores, we seek to better understand how people interacted with and adjusted to this dynamic landscape.