READING QUESTIONS: Glaciers
NAME________________________
GEOL 131
DUE: Tuesday, October 27th
Fall 2015
59 pts
All answers should be in your own words.
Glaciers: A Part of Two Basic Cycles (p. 192-195)
1.
Where are glaciers found today, and what percentage of Earth’s land surface do they cover? (2 pts)
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2. Match each type of glacier to its description: (2 pts)
a. Alpine
Ice from larger ice masses flowing through a valley to the ocean
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b. Continental
Small in size; form in mountains at high elevations
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c. Outlet
Cover uplands and elevated plateaus; larger than alpine glaciers
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d. Ice cap
Very large; completely bury underlying terrain
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3. EXTRA CREDIT: Is the North Pole covered by glacial ice? YES or NO
Formation and Movement of Glacial Ice (p. 195-198)
4. Describe how plastic flow works. (2 pts)
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5. Why does the zone of fracture behave in a brittle fashion? How thick is the zone of fracture, in feet? (2
pts)
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6. What is a crevasse, and where do they form? How deep can crevasses be? (3 pts)
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7. What climate condition must exist in a region in order for glaciers to form?
a. More snow must fall each winter than melts each summer
b. More snow must melt each winter than falls each summer
c. There must be high amounts of snowfall year round
d. The Earth must be in an Ice Age
e. Prevailing winds must be coming from the Arctic regions
f. The region must be at a very high elevation
8. What is the most significant difference between a glacier’s zone of accumulation and its zone of wastage?
(2 pts)
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9. What is calving? ____________________________________________________________________
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10. If accumulation in a glacier exceeds ablation, the glacier front will _________________.
11. EXTRA CREDIT: When a glacier front is retreating, the ice is moving backwards. TRUE or FALSE
Glacial Erosion (p. 199-202)
12. How do glaciers acquire sediment? (2 pts) ________________________________________________
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13. List two visible effects of glacial erosion. (2 pts)
a. _______________________________
b. _______________________________
14. How does a glaciated mountain valley differ in appearance from an unglaciated one? (2 pts)
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15. Label the erosional features created by alpine glaciation in the following figure: (4 pts)
A. _____________________________
E. ______________________________
B. _____________________________
F. ______________________________
C. _____________________________
G. ______________________________
D. _____________________________
Glacial Deposits (p. 203-207)
16. List two differences between till and stratified drift. (2 pts) ____________________________________
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17. How are medial and lateral moraines related? (2 pts) _________________________________________
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18. Describe what ground moraines and end moraines are. You do not need to describe how they form (2
pts).
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19. End moraines form ____ and ground moraines form ____. (Circle only ONE answer!)
a. when ablation exceeds accumulation; when accumulation and ablation are balanced
b. when accumulation exceeds ablation; when accumulation and ablation are balanced
c. when accumulation and ablation are balanced; under any conditions
d. under any conditions; when accumulation exceeds ablation
e. when accumulation and ablation are balanced; when ablation exceeds accumulation.
20. Sketch a simple side view of a drumlin. Use an arrow to show the direction the ice that formed it was
moving. (3 pts)
21. Outwash plains and valley trains both form by the same process. Describe this process. (3 pts)
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22. What is the difference between an outwash plain and a valley train? (2 pts) _______________________
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23. Match each glacial landform below with the correct description of how it forms. (3 pts)
a. Kame deposition of outwash by a meltwater stream beneath a glacier
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b. Esker deposition of outwash into depressions in a stagnant glacier front
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c. Kettle created by melting of blocks of ice left behind as a glacier retreats _____
Other Effects of Ice Age Glaciers (p. 207-210)
24. List and briefly describe three effects of Ice Age glaciation other than erosion and deposition. (6 pts)
a. ______________________________________________________________________________
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b. ______________________________________________________________________________
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c. ______________________________________________________________________________
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25. EXTRA CREDIT:How much has sea level risen since the last Glacial Maximum? ____________ meters
26. Why does sea level drop during Ice Ages? _________________________________________________
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27. Compare the two halves of Figure 26 and describe two ways in which water flow patterns changed in the
central United States during the Ice Age. (2 pts)
a. ______________________________________________________________________________
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b. ______________________________________________________________________________
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28. What is the difference between proglacial and pluvial lakes? (2 pts) _____________________________
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The Ice Age (p. 210-214)
29. About what percentage of Earth’s land surface was covered by glaciers during the Quaternary period?
__________ %
30. Why were ice sheets more extensive in the northern hemisphere than in the southern?
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31. EXTRA CREDIT: How does plate tectonics help explain what triggers ice ages? (2 pts)
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32. Explain why variations in Earth’s orbit are considered to be likely causes of glacial and interglacial
episodes of the Quaternary period. (2 pts)
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