2. Formation  Snow accumulation  More winter snowfall than summer melt  Glacier formation is similar to sedimentary rock formation

3. Types of Glaciers  Valley glaciers or alpine glaciation  Ice sheets or continental glaciation

4. Glaciers of the world  85% of glacier ice in Antarctica  10% of glacier ice in Greenland  Alpine glaciers comprise only 5% of world’s glacier ice

5. Alpine Glaciers  Form in valleys  Gravity causes glacier movement  Glaciers flow from higher to lower elevation

6. Alpine Glacier Flow Velocity  Overall downward flow velocity ranges from a few millimeters to 15 meters per day  Glaciers in warmer climate flow more quickly  Central part moves faster than sides  Surface moves faster than base  Glacier movement  Basal sliding  Plastic flow  Brittle/Rigid Zone

8. Continental Glaciers  Cover a large part of a continent  Gravity causes glacier movement  Glaciers flow downward and outward from a central high point  Plastic flow more common than basal sliding

15. Arctic Sea Ice  Fresh water, like glaciers, but do not flow like glaciers

16. And resulting landscapes Glacial Erosion

17. Erosion  Glacier movement erodes the bedrock underneath the glacier and can drastically change the landscape  Plucking  Abrasion  Polishing  Striations

18. Erratics & Striations

19. Alpine landscape features

21. Continental landscape features  All the sediment that a glacier picks up is deposited as unsorted and unlayered rock debris called “till”  Most features are created during glacial retreat

23. Effects on North America Ice Ages

24. Glacial Ages  A period of long-term reduction in Earth’s temperature, resulting in the presence of continental and polar ice sheets and alpine glaciers  Glacial periods  Interglacials  The last glacial period ended 10,000 years ago

25. Glacial Extent of Last Glacial Period

26. Laurentide Ice Sheet  Stevens Point is located right beyond the recessional moraine—in outwash plain

27. Glacial Erosion in Wisconsin

30. Whitewater Wisconsin Map Activity Topographic Maps

31. Topographic maps