The Geologic History and Future of the Great Lakes

The origin of the Great Lake basins of North America was a topic of great controversy in the mid-late nineteenth century. Canadian geologists notably Joseph Spencer and Sir John William Dawson favored erosion by rivers and phases of tectonic uplift and subsidence. The modern consensus is that the basins are primarily the result of glacial erosion and local overdeepening below sea level by successive North American ice sheets over the past 2.5 million years. I will review changing ideas on the geological evolution of mid-continent North America, the origin of the Great Lake basins and their lakes and discuss the impact of new mapping technology especially LIDAR (Light Detection and Ranging) which is revealing much about the work of Ice Age sheets. I will conclude by briefly discussing challenges to the waters of the Great Lakes created by human activity, especially urbanization of their surrounding watersheds and climate warming.

Lecturer – Nick Eyles

Nick was born in London, England and is Professor Emeritus of Geology at the University of Toronto where he has conducted award-winning research, teaching and public outreach since 1982. He is interested in the broader geological evolution of planet Earth over the past 4 billion years, and especially recurrent Ice Ages when large ice sheets and glaciers profoundly shaped Earth’s surface. He has worked on all seven continents. He hosted two 5 part documentary series; Geologic Journey – Canada and GJ – World for CBC’s Nature of Things which were nominated for several Gemini awards.