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Impenetrable Ice, Large Lakes, and Changing Coastlines: Evolution of the Lake Superior Region—Part 1

  • Madeline Island Museum 226 Colonel Woods Avenue La Pointe, WI, 54850 United States (map)

Free and Open to the Public

Speaker: Dr. Dave Ullman, Assistant Professor of Geoscience, at Northland College

Since the end of the most recent glaciation has been a period of dramatic change of the upper Midwest. What are now the rolling hills and scattered lakes of a gentle Midwestern landscape were once covered in a blanket of flowing and grinding ice, sculpting the underlying terrain and leaving behind many telltale markers of a changing climate. The Laurentide Ice Sheet scoured and deepened the Lake Superior basin creating the depths we see today. However, as ice retreated, Lake Superior took on many forms depending on whether glacial ice dammed the eastern drainage outlet at Sault Saint Marie.

This talk will review the recent data explaining the timing of glacial ice surrounding Lake Superior and the implications for past shorelines.


Dr. David Ullman's research interests fall along the intersection between climate and landscape. Variations in the Earth’s orbit and resulting fluctuations in greenhouse gases have led to profound changes in temperature and precipitation that have had large impacts on the earth’s surface. Specifically, his research is focused on refining the chronology of Laurentide Ice Sheet retreat from the Last Glacial Maximum until present and the mechanisms that led to such ice decline. Much of this work pertains to the extensive glacial record of the upper Midwest and Eastern Canada, rich with geomorphological clues of a drastically different recent past. He is also particularly interested in the climate that allowed for the development of these massive ice sheets, as well as what this past can tell us about our present and future climate.