1.4 Understand how moving ice acts as an agent of erosion and deposition. (Chapter 2)

1. 1.4 Understand how moving ice acts as an agent of erosion and deposition. (Chapter 2) There are two types of glaciation. • Alpine Glaciation • Continental Glaciation

2. 1.6.1 Distinguish between the terms alpine glaciation and continental glaciation. (P.32) Alpine Glaciers = • form high in mountain valleys above the snow-line Continental Glaciers= • cover parts of continental land masses near poles; eg Greenland & Antarctica

3. Similarities Both move (gravity, friction) Both cause erosion in 3 ways Bulldozing Glacial striations Freeze-n-pluck Both change the landscape (denudes, deposits) Both developed in constantly cold < 0 0C Differences Location Alpine = mountain Continental = earth poles Size Alpine = smaller Continental = larger Types of features formed (see next slides) Similarities & Differences between Alpine & Continental Glaciation

4. Erosion • Top:glacial polish or striations • Bottom show ice blocks part of freeze-n-pluck. Ice gets burried up when depressions left as material is removed. Leaves small ponds like at Butterpot Park)

5. Glaciers of the world Continental glaciers Alpine Glaciers

6. Surface of a glacier • Below, Torgat Mtns Lab • Side, Alaska

7. 1. Continental Glaciation • Define the terms • outwash plain • terminal moraine • erratics • drumlins • eskers. • See this picture p. 34 & question #12 on p.33-34

8. a) Outwash Plain Outwash plain= • Melt water flowing from glacier deposits silt like river deltas • Deposited in layers • Small particles carried further away (lightest) • Larger particles drop closer to the glacier (heaviest) • Letter? • B Outwash plain

9. b) Terminal Moraine Terminal Moraine • Heap or ridge of bulldozed gravel that marks the end of the forward motion of a glacier • **Think of loads of dirt dumped by a dump truck • This bulldozing happens at the snout. Letter for snout? • E • As glacier retreats it deposits debris/gravel in ridge perpendicular to flow • Letter for moraine? • C

10. c) Erratics Erratics = • Large boulders that were transported long distances and dropped • They now sit in a region and look very much out-of-place. • Letter? • H

11. d) Drumlins Drumlins (copy my diagram from board) • Egg shaped hill • Formed under glaciers • Sloped or Pointy end points in direction of ice flow • Formation • Glacier retreats as ice melts • Deposits of gravel made • Glacier moves forward 2nd time • Deposits are bull-dozed along and catches up in rough areas forming piles or drumlins. • Letter? • G

12. e) Eskers • Eskers= • Long deposits of eroded glacial material • Formed by sub-glacial streams that deposit material like all rivers. • Parallel with glacier flow • Highways of the North!! • Letter? • F

13. Examine evidence for the direction of movement of glaciers. (P. 34 question # 13) • Evidence for direction of movement? • Sloped end of drumlin** • Location of terminal moraine (could be from 2 directions) • Eskers (only tells axis) • What is direction of glacier movement in this picture?

14. Identify the following continental features. (1) • Drumlin in Alberta • Drumlins may rise to elevations exceeding 30 m and extend, at least, to lengths of 800 m. • This feature shown above is about 35 m high, and at least 250 m long. • In which direction did the glacier travel?

15. Identify the following continental features.(2) • Esker, NWT • In which direction did the glacier travel?

16. Identify the following continental features.(3) • Glacial delta at Hermitage, Hermitage Peninsula. • The great mass of sand and gravel on which the village is situated was deposited at the margin of a glacier which, during the final retreat of the Newfoundland ice sheet, stagnated in Hermitage Bay on the north side of the peninsula. At that time the sea stood more than 20 m higher and the meltwater from the glacier built a large flat-topped delta and terrace. Depressions in the gravel mass (kettles) formed as blocks of buried glacier ice melted.

17. Identify the following continental features.(4) • Drumlin in Burgeo

18. Identify the following continental features.(5) • Erratic in Labrador

19. Identify the following continental features.(6) • See long thin lines of deposits? • Eskers or glacial river deposits • A common sight on transatlantic flights, the narrow sinuous branching ridges are eskers composed of gravel and sand that was deposited by glacial meltwater in tunnels beneath an ice sheet.

20. Alpine glaciers • Alpine glaciers are like very slow moving rivers of ice flowing down high mountain valleys.

21. 2. Alpine Glaciation • Define the terms • cirque, • arête, • hanging valley • Lateral & medial moraine • terminal moraine. • Read pages 34-7, see diagram page 36, chart page 37 & question #14 page 36

22. a) Cirque Cirque = • a circular hollow cut into bedrock during glaciation • Side and back walls are steep but front wall opens downward Cirque Formation • Alpine glacier freezes onto mountain valley and as is proceeds it plucks rock from the mountain top leaving the cirque shape.

23. b) Arête Arête= • Steep knife edged ridge between two cirques in a mountainous region.

24. c) Hanging Valley Hanging Valley = • A high level tributary valley from which the ground falls sharply to the level of the lower, main valley. • The depth of the lower valley is due to more severe glaciation.

25. d) Lateral/Medial Moraine & (e) Terminal Moraine Lateral Moraines = • Landform deposited at the side of a glacier Medial Moraines= • Where 2 lateral moraines join when 2 glaciers meet Terminal Moraines = • deposits that mark the farthest extent of the glacier • Lateral Moraines • Terminal Moraine

26. Describe how fiords are formed. (P.37) 1. Alpine Glaciers erode troughs & valleys in the mountain (at weakest points) 2. Glacier valley reaches the coast. 3. Glacier melts and sea water floods the valley 4. In case of Western Brook Pond, Gros Morne, coast was “drowned” and when ice melted land rebounded cutting off fiords form ocean.

27. Name the alpine feature? (1) • See the black lines in the middle of the ice itself • Medial moraine

28. Name the alpine feature? (2) • See the sharp ridges • Cirques

29. Name the alpine features? (3 & 4) • Now covered in vegetation • Name? • CIRQUE • Erratic (continental feature)

30. Name the Alpine feature? (5) • Right: Hanging Valley at Trout River Pond in Gros Morne National park . • Left: Hanging valleys in Western Brook Pond (see next slide)

31. Aerial view of Western Brook trough, Newfoundland • This great chasm cuts the margin of the flat plateau called the Long Range Mountains. • This gorge originated simply as a normal river valley that drained the plateau while it was near sea level in preglacial time. • As the plateau was raised by crustal uplift and the ice age began, the valley was progressively deepened and widened by powerful outlet glaciers, which drained a local ice cap.

32. Name the Alpine feature? (6) • 1. Norway is well known for its abundant fiords • 2. Fiord: Bakers Brook Pond, Gros Morne

33. Name the Alpine feature? (7) • Center arrow? • Terminal moraine • Outside arrows? • Lateral moraines

34. Photo Gallery

35. Photo Gallery

36. Glaciers done! • Now complete xword & related sheets