1. Glaciers

2. Glacier - a thick ice mass that originates on land from the accumulation, compaction, and recrystallization of snow.
Formation of glacial ice from snow

3. 1. Ice sheets, Continental glacier
Glacier Types
1. Ice sheets, Continental glacier
Large scale – cover 10% of Earth’s land
Greenland – 1.7 million km2
Antartica – 13.9 million km2

4. Continental Glaciers

5. 2. Valley, Mountain, Alpine
Glacier Types
2. Valley, Mountain, Alpine
Smaller than ice sheets
Lengths greater than widths
Only cover a small region

6. Alpine Glaciers

7. Greenland

9. Bylot Island, Canada

10. Glacier movement
50 meters
100 meters

11. Glacier movement

12. Glacier movement Plastic flow – flowing solid 200 m/yr
Basal slip – movement over bedrock 200 m/yr

14. Glacier movement Rotation of Grains Melting & Freezing
Internal Slipping

18. Glacier budget In: Zone of accumulation – snow accumulates
Out: Zone of ablation – general term for loss of ice or snow from a glacier
Melting
Calving - icebergs

19. Glacier budget

20. Glacial Calving

21. Dry calving with recumbent folds

23. Sub-glacial River

24. Surface Drainage

25. Glacier Erosion Plucking – loosen and lift blocks of rock
Abrasion – rock flour
Striations – grooves scratched in bedrock

26. Glacial Landforms Mountian Glaciers – tend to accentuate the landscape
Continental Glaciers – tend to subdue the landscape

27. Mountain Glaciers

28. Mountain Glaciers Landforms
Hanging valley – a tributary that enters a glacial trough high above the floor of the trough.
Arete – a narrow , knifelike ridge separating two adjacent glaciated valleys.
Horn – a pyramid-like peak formed by glacial action in three or more cirques surrounding a mountain summit.

29. Mountain Glaciers Landforms
Tarn – a small lake in a cirque.
Cirque – an ampitheater-shaped basin at the head of a glaciated valley.
Truncated spurs – eroded triangular shaped cliffs in glaciated valleys.
Glacial trough – U-shaped glacial valley

30. Mountain Glaciers

34. Ice Dammed Lake

40. Glacial Deposits
Drift (general term) – Sediment deposited on land or in water as a result of glaciation.
1. Till – Unsorted debris transported by glaciers and deposited on land.
2. Sorted Sediments – Sediments transported by melt water are deposited in Eskers and in the Outwash Plain.

43. Till Deposits
Moraines - a pile of debris that has been transported and deposited by a glacier
Erratics - boulders left on the surface

44. Erratic

46. Terminal Moraine - Debris pushed along in front of the glacier
Ground Moraine - debris accumulated under the glacier