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

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

7. When the climate began to warm, glaciers began to retreat.

8. When the climate began to warm, glaciers began to retreat.

9. When the climate began to warm, glaciers began to retreat.

10. When the climate began to warm, glaciers began to retreat.

11. Striations

12. Kettle Lakes

13. S.E. Michigan Kettle Lakes

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

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

16. Other glacial evidence…
Kalkaska, Michigan

19. 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.

20. 11.14 Explain what happens to Earth’s crust when a glacier is removed.
Isostatic Rebound
The upward movement of the Earth’s crust

21. 11.15 Identify glacial features using a Topographic Map
Glacial topo map lab: