READING QUESTIONS: Chapter 7, Glaciers GEOL 131 Fall 2018 63 pts NAME DUE: Tuesday, October 23 Glaciers: A Part of Two Basic Cycles (p. 192-195) 1. Match each type of glacier to its description: (2 pts) a. Alpine Ice from larger ice masses flowing through a valley to the ocean b. Continental Small in size; form in mountains at high elevations c. Outlet Cover uplands and elevated plateaus; larger than alpine glaciers d. Ice cap Very large; completely bury underlying terrain 2. EXTRA CREDIT: Is the North Pole covered by glacial ice? YES or NO Formation and Movement of Glacial Ice (p. 195-198) 3. What is the snowline? a. The depth below which plastic flow occurs b. The highest altitude at which snow can become glacial ice c. The elevation above which snow remains all year round d. All of the above 4. What is plastic flow? a. Microscopic layers of ice crystals sliding over one another under pressure b. The entire glacier sliding downslope as a single unit c. The movement of meltwater through a glacier d. The carving of ice tunnels beneath a glacier 5. Why does the zone of fracture behave in a brittle fashion? (2 pts)
6. What climate condition must exist in a region in order for glaciers to form? (Circle one answer.) 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 7. If accumulation in a glacier exceeds ablation, the glacier front will. 8. EXTRA CREDIT: When a glacier front is retreating, the ice is moving backwards. TRUE or FALSE Glacial Erosion (p. 199-202) 9. Fill in the blanks in these sentences from the textbook (p.199): as a glacier flows over a bedrock surface, it loosens and blocks of rock and incorporates them into the ice. This process, known as, occurs when meltwater penetrates the crack and beneath a glacier and. Because the water expands when it freezes, it exerts tremendous that the rock loose. (7 pts) 10. Fill in the blanks in this sentence from the textbook (p. 199): As the ice and its load of rock fragments over the bedrock, they function like, smoothing and the surface below. The previous sentence describes the glacial erosion process called. (4 pts) 11. The process described in question 10 creates two distinctive types of erosional surfaces on rock, both shown in Figure 13. What are these two surfaces? (Circle ONE answer.) a. Striations (scratches and grooves) and abrasion b. Striations and polishing c. Abrasion and plucking d. Abrasion and rock flour
12. Label the erosional features created by alpine glaciation in the following figure: (6 pts) A. E. B. Paternoster Lakes F. C. G. D. Glacial Deposits (p. 203-207) 13. List two differences between till and stratified drift. (2 pts) 14. Fill in the blanks in these sentences from the textbook (p. 204-205): The sides of a accumulate large quantities of from the valley walls. When the glacier wastes away, the materials are left as, called, along the sides of the valley. are formed when two valley glaciers to form a single ice stream. The till that was once carried along the of each glacier joins to form a single dark of debris the newly enlarged glacier. (9 pts)
15. Fill in the blanks in these sentences from the book (p. 205): An is a ridge of till that forms at the terminus of a glacier or ice sheet whenever the terminus is stationary forms when the ice is near the end of the glacier at a rate the forward advance of the glacier. Although the terminus of the glacier is, the ice continues to, delivering a continuous supply of sediment As the ice melts, the till is and the end moraine. The longer the ice front remains, the the ridge of till will become. (10 pts) 16. Fill in the blanks in these sentences from the book (p. 205): Eventually, exceeds. At this point, the front of the glacier begins to in the direction from which it originally advanced. However, as the ice front, the conveyor-belt action of the glacier continues to provide fresh supplies of to the terminus. In this manner, a large quantity of till is deposited as the ice melts away, creating a, undulating. This gently rolling layer of till is termed a. (8 pts) 17. The photo below shows a drumlin. Which way was the ice flowing that deposited this feature? a. From the left b. From the right c. Can t tell from the photo
18. Match each glacial landform with the correct description of how it forms. (3 pts) a. Kame deposition of stratified drift by a meltwater stream beneath a glacier b. Esker deposition of stratified drift into depressions in a stagnant glacier front c. Kettle created by melting of blocks of ice left behind as a glacier retreats Other Effects of the Ice Age Glaciers (p. 207-210) 19. The growth of ice sheets caused a worldwide (RISE or DROP) in sea level. Circle one answer. The Ice Age (p. 210-214) 20. Explain why there is evidence of glaciers on continents such as Africa and India. (2 pts) 21. During the Ice Age, concentrations of carbon dioxide and methane were (INCREASED or REDUCED). Circle one answer.