Landforms ESCI-1020 Chapter 7

25. Desertification is notcaused by which of the following? a. overgrazing b. climate change c. erosion and salinization of crop land d. deforestation e. All of these

e. All of these

15. Significant loess deposits are found in the a. Mississippi and Missouri valleys. b. eastern Washington region. c. Ukraine in the former Soviet Union. d. Loess Plateau of China, some 300,000 km2 (115,800 mi2). *e. All of these regions contain loess.

e. All of these regions contain loess.

3. A 50 kmph (30 mph.) wind blowing for 24 hours moves how much sand over 1m2 (1yd2) a. 10 kg (22 lbs.) b. 50 kg (110 lbs.) c. 500 kg (1100 lbs.) d. 1000 kg (2200 lbs.) e. 2000 kg (44000 lbs.)

d. 1000 kg (2200 lbs.)

22. Buttes, mesas, and inselbergs represent a. pinnacles of rock and rock masses that were uplifted by compressional forces. b. erosional remnants of a once extensive and continuous rock layer. c. erosional remnants of vertically tilted strata. d. the erosional remnants of volcanoes (i.e., volcanic necks).

b. erosional remnants of a once extensive and continuous rock layer.

20. Which of the following is notanother name for an alluvial fan? a. qanat b. karex c. foggara d. gibber plain

d. gibber plain

7. Abrasion is usually confined to a zone which extends up to __________ above the ground. a. 1 cm (0.39 in.) b. 1 m (3.28 ft.) c. 5 m (16.4 ft.) d. 10 m (32.4 ft.)

b. 1 m (3.28 ft.)

27. Longitudinal sand dunes are oriented parallel to the prevailing wind. a. True b. False

b. false

26. Water is essential to the formation of a desert pavement. a. True b. False

a. True

30. The Colorado River system is experiencing a drought that is more severe than any in the historic record. a. True b. False

a. True

21. A continuous depositional apron, or __________, may form if individual alluvial fans coalesce into one sloping surface. This feature contrasts with a __________, which is an erosional surface along a mountain front where bedrock is covered by a thin veneer of alluvium. a. bajada; pediment b. pediment; bajada c. playa; bolson d. horst; graben

a. bajada; pediment

5. The formation of desert pavement a. involves both wind and water. b. is produced by abrasion only. c. is not related to deflation. d. involves wind processes only.

a. involves both wind and water.

28. Wind-blown loess deposits are only derived from glacial and periglacial sources. a. True b. False

b. False

29. Soils formed from loess tend to be infertile. a. True b. False

b. False

19. Which of the following is nottrue of alluvial fans? a. They often serve as good sources of groundwater. b. They frequently occur in the eastern United States. c. The largest sized sediment is found near the top of the fan, and the smallest near the bottom. d. They are depositional features.

b. They frequently occur in the eastern United States.

24. Addition of more dams on the Colorado River would result in __________ available water because __________. a. more; of the obvious fact that dams create reservoirs which store water that would otherwise flow into the sea b. less; some of the impounded water would seep into rock and become unavailable c. less; some of the water would evaporate d. both less; some of the impounded water would seep into rock and become unavailable and less; some of the water would evaporate

d. both less; some of the impounded water would seep into rock and become unavailable and less; some of the water would evaporate

1. For purposes of discussing eolian processes, the wind acts like a a. solid. b. gas. c. plasma. d. fluid.

d. fluid.

9. Pebbles can be moved by __________ in a process known as __________. a. deflation; saltation b. deflation; surface creep c. saltating particles; deflation d. saltating particles; surface creep

d. saltating particles; surface creep

17. In which region of the United States. are eolian processes most effective? a. northeast b. southeast c. northwest d. southwest

d. southwest

13. Relatively small dunes that are crescentic in shape are termed __________ dunes. a. barchan b. star c. longitudinal d. seif

a. barchan

16. The loess deposits in North America are derived from __________, and those in China are derived from __________. a. glacial and periglacial regions; glacial and periglacial regions b. glacial and periglacial regions; deserts c. deserts; glacial and periglacial regions d. deserts; deserts

b. glacial and periglacial regions; deserts

2. Which of the following grain sizes is most readily moved by the wind? a. large b. intermediate c. small

b. intermediate

11. Which side of a dune typically has a slope angle equal to that of the angle of repose for sand? a. windward b. leeward c. stoss d. top

b. leeward

12. Linear dunes and seif dunes are oriented a. parallel to the wind. b. perpendicular to the wind. c. randomly in relation to wind direction.

b. perpendicular to the wind.

10. Small sized sand that is blown in a strong wind will produce ripples that are a. closely spaced. b. widely spaced. c. It is impossible to say what the spacing will be because there is no relationship between ripple spacing, sand size, and wind velocity.

b. widely spaced.

8. Elongated, streamlined ridges aligned parallel to the most effective wind direction are called a. ventifacts. b. yardangs. c. desert pavements. d. alluvial rock structures.

b. yardangs.

4. The often-sited work on eolian processes is The Physics of Blown Sand and Desert Duneswritten by a. William Morris Davis. b. John Wesley Powell. c. Ralph A. Bagnold. d. Edward Abbey.

c. Ralph A. Bagnold.

14. A crescent-shaped dune with anchoring vegetation is called a a. barchanoid ridge. b. longitudinal dune. c. parabolic dune. d. reversing dune.

c. parabolic dune.

6. Which of the following terms isnota correct reference to a desert pavement? a. gibber plain b. lag gravels c. sand seas d. reg desert

c. sand seas

18. The spatial distribution of Earth's dry regions are attributable to all of the following factors except a. subtropical high-pressure cells between 15° and 35° N and S latitudes. b. rain shadows to the lee of mountain ranges. c. the equatorial low-pressure region and the ITCZ. d. great distances from moisture-bearing air masses.

c. the equatorial low-pressure region and the ITCZ.

23. The majorerosional force in the desert is a. wind. b. the eolian process. c. water and fluvial processes. d. human activity.

c. water and fluvial processes.