Chapter 3 Section 4 Glaciers

1. Chapter 3 Section 4 Glaciers

2. Glaciers Agent of erosion • Moving mass of ice and snow • Form when more snow falls than melts

3. Glaciers Advancing Glacier-When the glacier increases in size and slides forward due to gravity Retreating Glacier-When the glacier decreases in size because it is melting

4. 2 Kinds of Glaciers

5. Valley Glacier (Alpine) Muddy River Glacier, Alaska 1948 • Located in mountainous areas • Snow and ice build up in a long, narrow v-shaped river valley

7. Continental Glacier • Huge mass of ice and snow (larger than valley glacier) • Usually covers a large portion of land like a continent • Only tallest peaks of land are exposed • Today cover 10% of earth's surface (found in Greenland & Antarctica)

8. What is NOT a glacier?

9. are in water, not on land

10. are much smaller than glaciers

11. About ⅞of an iceberg is below the water line.

12. Last Ice Age White is land covered in ice. You are here. Continental glaciers cover large portions of the world at one time http://cabrillo.edu/~crsmith/glacloop.gif

13. Last Ice Age Blue is land covered in ice. You are here.

14. Leading Edge of Glacier Person

15. How do glaciers form and move? Snow accumulates and piles up faster than it melts Weight of snow is great enough to compress bottom layers into ice Ice on bottom partially melts and becomes putty like Whole mass begins to slide on this putty-like layer When the mass of the glacier is too great, gravity pulls

17. How do glaciers erode Earth’s surface?

18. Abrasion & Plucking Abrasion-Glaciers gouge and scratch land below as it moves Plucking-Glacier picking up rocks as it travels

19. How do glaciers erode Earth’s surface? • As they move, glaciers act as bulldozers pushing loose material out of their path • These eroded sediments are added to the mass of the glacier (plucking) or piled up along its sides • Glaciers also grind rock and soil that isn't loose (abrasion)

20. Striations The “stripes” scratched into rocks by glacial abrasion.

21. How do glaciers deposit sediment?

22. Where a glacier deposits mounds or ridges of till (sediment) Moraine

23. The ridge of till at the farthest point reached by a glacier (Long Island & Cape Cod-terminal moraine from last ice age) Terminal Moraine

24. How do glaciers deposit sediment? • Glaciers begin to melt and lose their energy of motion • Begin to deposit sediments they carry (till ) • Till at the edges of a glacier (moraine) • Till at the end of a glacier (terminal moraine)

25. How do glaciers shape the land? What kinds of glacial landforms are created?

26. Kettle Lake Formation Kettle-small depression formed by a chunk of glacial ice left behind

27. Kettle Lake Contain water all year long Kettle lake- kettle that fills with water from melted ice blocks

28. Glacial Lake Contain water all year long Glacial lake- Forms like a kettle lake, but high in the mountains

30. Horn-mountains with sharp pointed peaks Arête-sharp edges that run down mountain sides (separating 2 cirques)

31. Cirque-a bowl-shaped hollow in mountain side where glacier began

32. U-shaped valley- a valley carved by glaciers in U-shape, usually from a v-shaped river valley

34. Fiord (Fjord) Fiord- a coastal valley cut by glacier that fills in with water when seas rise from glacial melt

35. Drumlin-mounds of till that a glacier slides over and as the glacier melts back the mound becomes uneven Glacier Direction of flow

36. Glacier Features

37. The following photos are courtesy of a former student’s family vacation to Alaska

38. What am I showing you? Where a glacier makes an ICEBERG

39. What am I showing you? The TILL from plucking & abrasion that will be laid down when the glacier melts

40. What am I showing you? The carving power of a glacier U-SHAPED VALLEY, HORN, ARÊTE

41. What am I showing you? Drumlin -Which direction was the glacier flowing?

42. What am I showing you? Glacial Lake

43. What am I showing you? Valley Glacier