1. Michigan’s Glacial History

2. How do scientists prove that glaciers once covered Michigan?

3. Each of the Great Lakes began as a river. Image from Earth Science, Tarbuck and Lutgens, 2003

4. Theoretical Michigan Before the Ice Age

5. When the climate cooled… Ice advanced southward from Canada over the Great Lakes Region.

6. As the climate cooled… The rivers froze. Glaciers moved through them – widening and deepening them to form today’s lake bottoms.

8. 14,500 & 14,000

9. 13,000

10. 11,000 damned to the North

11. 9,500 two outlets

12. When the climate began to warm, glaciers began to retreat. http://www.msstate.edu/dept/geosciences/CT/TIG/WEBSITES/LOCAL/Spring2002/Michael_Marsicek/images/Great_Lakes_Formation.gif

13. When the climate began to warm, glaciers began to retreat. http://www.msstate.edu/dept/geosciences/CT/TIG/WEBSITES/LOCAL/Spring2002/Michael_Marsicek/images/Great_Lakes_Formation.gif

14. When the climate began to warm, glaciers began to retreat. http://www.msstate.edu/dept/geosciences/CT/TIG/WEBSITES/LOCAL/Spring2002/Michael_Marsicek/images/Great_Lakes_Formation.gif

15. When the climate began to warm, glaciers began to retreat. http://www.msstate.edu/dept/geosciences/CT/TIG/WEBSITES/LOCAL/Spring2002/Michael_Marsicek/images/Great_Lakes_Formation.gif

16. http://www.ofps.ucar.edu/gapp/networks/images/greatlakes_map.jpg

18. Kettle Lakes

19. S.E. Michigan Kettle Lakes

20. Moraine Deposits = unsorted sediments Moraines are made of unsorted sediments. Only mass movements and glaciers deposit unsorted sediments. Mass Movements? Glaciers??

21. Moraine Deposits have the same shape as the Great Lakes. Michigan moraines run parallel to the shoreline. So how do they relate??

23. Other glacial evidence… Kalkaska, Michigan

26. Why do scientists believe that glaciers once covered Michigan? Michigan is covered with unsorted moraine deposits. The moraine deposits follow the outline of Great Lakes. Other depositional features such as drumlins and kettle lakes are found throughout Michigan. Erosional features like striations are found in Michigan as well.

27. 11.14 Explain what happens to Earth’s crust when a glacier is removed. Isostatic Rebound –The upward movement of the Earth’s crust

28. Glacial topo map lab: 11.15 Identify glacial features using a Topographic Map