CHAPTER 17 Concept Review
The Human Sphere: The Mammoth Hunters
1. About when did the mainland mammoth populations in North America and Eurasia disappear? Why did the mammoth go extinct?
2. Why do people seek the remains of mammoths preserved in frozen ground?
17.1 Frozen Ground: Periglacial Environments
3. What does “periglacial” mean? Are there glaciers in periglacial environments?
4. What is permafrost, and how is it defined? Where does it occur?
5. Why are many Arctic lakes emitting methane?
6. What are pingos? What is patterned ground? Explain how they form.
7. In the context of the active layer, explain why “drunken forests” occur. Why might rail lines and pipelines sink into permafrost? How do engineers prevent sinking from happening?
17.2 About Glaciers
8. What is glacial drift? Give examples of drift.
9. What is a glacier? Where are glaciers found?
10. What are the three steps to glacier formation? What two requirements must first be met before a glacier can begin to form?
11. By what two processes do glaciers move?
12. What is glacier mass balance? Compare and contrast the zone of accumulation, the zone of ablation, and the equilibrium line.
13. What is a glacier’s toe? Why does it move upslope and downslope?
14. What does it mean to say that a glacier is in retreat? What is retreating? What causes a glacier to retreat?
15. Compare and contrast the geographic settings of an alpine glacier and an ice sheet. How do their sizes compare?
16. What are the four types of alpine glaciers? Describe where each occurs.
17. What is an iceberg? How does one form?
17.3 Carving by Ice: Glacial Erosion
18. What effect does glacial erosion have on mountain height?
19. What are plucking and abrasion? How do these processes allow glacial ice to carve into hard bedrock?
20. What are glacial striations and glacial polish?
21. What is glacial flour? What effect does it have on the appearance of a lake?
22. By what two means are rock fragments moved downslope by glaciers?
23. What is an outwash plain? Where and how do they form?
24. What is a glaciofluvial process?
25. What is a proglacial lake? Where do they form?
26. Describe a cirque and explain how cirques form.
27. What are arêtes, horns, and cols, and how do they form?
28. Describe the shape of a glacial valley. What kind of glacier forms glacial valleys?
29. Compare a trunk glacier with a tributary glacier. Describe how a hanging valley forms from these glaciers.
30. What are paternoster lakes and how do they form?
31. What is a fjord? Why are there no fjords at middle and low latitudes?
17.4 Building by Ice: Glacial Deposition
32. Why are stream deposits sorted but glacial deposits unsorted?
33. What is till? What is the relationship of till to moraines?
34. Differentiate between lateral, medial, terminal, and recessional moraines.
35. Describe the formation of drumlins, eskers, and kettle holes in the context of ice sheet deposits.
36. What is loess and how does it form?
17.5 Geographic Perspectives: Polar Ice Sheets and Sea Level
37. On what continent is most of the cryosphere’s ice stored? As a percentage, how much of the cryosphere is on that continent?
38. Describe Greenland’s loss of ice in terms of the number of summer melt days, changing ice sheet albedo, and outlet glacier flow rates.
39. What is a supraglacial lake? How is it related to the speed of outflow glaciers on Greenland?
40. What large ice shelf recently broke apart? Explain the role of supraglacial lakes in causing it to break apart.
41. What happens to the speed of an outlet glacier when an ice shelf that supports it breaks apart?
42. How much has sea level risen in the last century? How much could sea level rise by the end of this century?
43. How many people worldwide live in coastal areas within 1 m of sea level?