Physical Geology Exploring the Earth 6th Edition By James S. Monroe - Test Bank

Physical Geology Exploring the Earth 6th Edition By James S. Monroe – Test Bank

 

Instant Download – Complete Test Bank With Answers

 

 

Sample Questions Are Posted Below

 

CHAPTER 18 ‑ TEST QUESTIONS

 

TRUE OR FALSE

 

1. Agriculture and overgrazing on lands adjacent to existing deserts can cause desertification.

 

ANSWER:     true

 

2. Deserts are expanding through a process called desertification, destroying once productive rangeland and cropland.

 

ANSWER:     true

 

3. Surface creep in a desert is a type of mass wasting.

 

ANSWER:     false

 

4. Wind is as effective an agent of erosion and deposition as water.

 

ANSWER:     false

 

5. Wind is as effective an agent of landform creation as is water.

 

ANSWER:     false

 

6. Wind transports sediment in the same way as water – as dissolved load, suspended load, and bed load.

 

ANSWER:     false

 

7. Even if not presently found in desert climates, all dunes originated in desert conditions.

 

ANSWER:     false

 

8. Although loess may originate in deserts it is not deposited in them.

 

ANSWER:     true

 

9. All dunes have crests oriented perpendicular to the direction of wind movement.

 

ANSWER:     false

 

10. Barchan dunes form in low relief terrain with limited vegetation, limited sand supply, and a constant wind direction.

 

ANSWER:     true

 

11. The water table in deserts with through-flowing streams slopes toward the streams.

 

ANSWER:     false

 

12. All true deserts have widespread sand dunes.

 

ANSWER:     false

 

13. Desert pavement is the result of deflation of desert surfaces.

 

ANSWER:     true

 

14. All true deserts are found within the low and middle latitudes.

 

ANSWER:     false

 

15. Deserts are the one environment where wind erosion is more important than water erosion.

 

ANSWER:     false

 

16. During the Pleistocene Epoch pluvial lakes occupied the region of Death Valley.

 

ANSWER:     true

 

17. The same geological agents work in all deserts, so landforms of various deserts are similar.

 

ANSWER:     false

 

18. Deserts are common in dry climates at low to mid latitudes.

 

ANSWER:     true

 

19. Mechanical weathering dominates over chemical weathering in desert regions.

 

ANSWER:     true

 

20. Because of the abundance of sand and dust in the desert environment, soils are generally thicker than those found in more humid environments.

 

ANSWER:     true

 

21. Wind erosion appears to be most important in the formation of pediments.

 

ANSWER:     false

 

22. The coarsest-grained material in an alluvial fan is found along its margins.

 

ANSWER:     false

 

23. Alluvial fan sediment is deposited by flashflood, sheetflow, mudflow and debris flow.

 

ANSWER:     true

 

24. Desert landscapes are as dynamic as wetter landscapes, but change happens more slowly.

 

ANSWER:     true

 

MULTIPLE CHOICE

 

25. Wind-blown sand is generally moved in
26. water
27. suspension load

*              C. saltating load

1. debris flows
2. A and C

 

 

 

 

 

26. Desertification is the result of which of the following factors:
27. global warming
28. cropping marginal lands
29. overgrazing marginal lands
30. clearing of natural vegetation

*              E. all of the above

 

27. Which of the following landforms are NOT formed in deserts?
28. sand dunes
29. inselbergs
30. alluvial fans
31. playa lakes

*              E. none of the above

 

 

28. Silt- and clay-sized sediment in deserts are moved

*              A. by suspension

1. by saltation
2. in solution
3. by erosion

 

29. Wind is capable of erosion by which of the following process(es)?
30. saltation
31. suspension
32. abrasion
33. deflation

*              E. B and C

 

30. Ventifacts would support which of the following hypotheses?
31. wind is the major agent of erosion in deserts

*              B. wind-blown sediment is capable of abrasion

1. venting is a major means of erosion in deserts
2. wind is capable of scouring soft rock
3. A and B

 

31. Ventifacts on the north-facing side of a surface stone would suggest that the prevailing direction of wind is FROM the

*              A. north

1. south
2. east
3. west

 

32. Sand dunes result when
33. sand supply is plentiful
34. wind direction is consistently in one direction
35. vegetation is sparse

*              D. A and C

1. all of the above

 

33. In low relief terrain with limited vegetation, limited sand supply, and a constant wind direction, which of the following dune types will develop?

*              A. barchan dunes

1. longitudinal dunes
2. transverse dunes
3. parabolic dunes
4. star dunes

 

 

34. In low relief terrain with limited vegetation, abundant sand supply, and a constant wind direction, which of the following dune types will develop?
35. barchan dunes
36. longitudinal dunes

*              C. transverse dunes

1. parabolic dunes
2. star dunes

 

35. In low relief terrain with a partial cover of vegetation, limited sand supply, and a constant wind direction, which of the following dune types will develop?
36. barchan dunes
37. longitudinal dunes
38. transverse dunes

*              D. parabolic dunes

1. star dunes

 

36. The source of loess is
37. floodplains of rivers
38. deserts
39. glacial outwash

*              D. A and C

1. all of the above

 

37. Which of the following combinations of desert regions are the result of climate in the mid-latitude high pressure belt?

*              A. the Gobi Desert, the Sahara Desert of Northern Africa, and the Arabian Desert of the Mideast

1. the Gobi Desert, the Great Basin, and the Sahara Desert of Northern Africa, and
2. the Arabian Desert of the Mideast, Patagonia, and the Atacama Desert of Chile and Peru
3. Patagonia, the Great Basin, and the Atacama Desert of Chile and Peru
4. Patagonia, the Sahara Desert of Northern Africa, and the Australian “outback”

 

38. Which of the following combinations of desert regions are the result of being within a rainshadow?
39. the Gobi Desert, the Sahara Desert of Northern Africa, and the Arabian Desert of the Mideast

*              B. Patagonia, the Great Basin, and the Atacama Desert of Chile and Peru

1. the Gobi Desert, the Great Basin, and the Sahara Desert of Northern Africa, and
2. the Arabian Desert of the Mideast, Patagonia, and the Atacama Desert of Chile and Peru
3. Patagonia, the Sahara Desert of Northern Africa, and the Australian “outback”

 

39. Deserts form in association with mountain ranges because
40. the mountains provide runoff, the primary agent of erosion in deserts

*              B. the mountains cause a decrease in rainfall on the downwind side or lee side

1. associated air masses are warm and dry
2. vegetation does not do well in shadows

 

40. Desert soils are thin and patchy because
41. sand, silt, and clay are blown away
42. vegetation is sparse
43. rainfall is limited
44. chemical weathering is not dominant

*              E. all of the above

 

41. Which of the following statements is accurate concerning deserts?
42. the processes and landforms in deserts are unique to deserts

*              B. the geologic processes operating in deserts also operate in other environments

1. the extent of deserts is constant over time and will not likely change in the future
2. deserts are an ephemeral feature, present only until vegetation can stabilize sediment

 

 

FILL-IN

 

42. __________ dunes are crescent-shaped dunes whose tips point downwind.

 

ANSWER:     barchan

 

43. Wind transports sediment in __________ or __________.

 

ANSWER:     suspension, saltation or traction

 

44. Sediment is transported by wind as __________ or __________ load.

 

ANSWER:     suspended, bed

 

45. Long parallel ridges of sand aligned parallel to the wind direction are known as __________ dunes.

 

ANSWER:     longitudinal

 

46. Long parallel ridges of sand aligned perpendicular to wind flow are known as __________ dunes.

 

ANSWER:     transverse

 

47. __________ dunes form when vegetation cover is broken by deflation and the dune tips point upwind.

 

ANSWER:     parabolic

 

48. __________ are large-scale ventifacts, elongated in the direction of the wind.

 

ANSWER:     yardangs

 

49. The Coriolis effect causes winds to be deflected to the _______ of their direction of motion in the North hemisphere and to the _______ of their direction of motion in the South hemisphere.

 

ANSWER:     right, left

 

50. High pressure troughs exist where cooler, denser air begins to descend at about _______ to _______ degrees latitude, N and S.

 

ANSWER:     20, 30

 

51. Fan-shaped landforms that develop in deserts adjacent to highlands are known as __________ __________.

 

ANSWER:      alluvial fans

 

52. An isolated mountain that rises from the flat plain of a desert is known as a(n) __________.

 

ANSWER:      inselberg

 

53. The most effective agent of erosion in the deserts is by ___________.

 

ANSWER:     water

 

54. Wind erodes by two processes, ___________ and ___________.

 

ANSWER:     abrasion, deflation

 

 

 

MATCHING

 

55. Match the following desert regions with the type of desert they represent.

______ Gobi Desert                                                                                        A. mid-latitude high pressure belt

______ Sahara Desert                                                                                    B. rainshadow

______ Patagonia

______ Arabian Desert

______ Great Basin

______ Atacama Desert

______ Australian “outback”

 

ANSWER:     A, A, B, A, B, B, A

 

56. Match the following desert features with their process of formation.

_____ desert pavement                                                                                 A. abrasion

_____ventifacts                                                                                              B. deflation

_____blowouts

_____ yardangs

 

ANSWER:     B, A, B, A

 

57. Match the following dune type with the appropriate sand supply.

_____barchan                                                                                                 A. limited sand supply

_____longitudinal                                                                                          B. abundant sand supply

_____parabolic

_____transverse

 

ANSWER:     A, A, B, B

 

58. Match the following dune type with the appropriate wind condition.

_____barchan                                                                                                 A. constant wind direction

_____longitudinal                                                                                          B. convergent wind directions

_____parabolic                                                                                               C. variable wind directions

_____star

 

ANSWER:     A, B, A, C

 

59. Match the desert landform with the appropriate agent of formation.

_____alluvial fan                                                                                           A. wind

_____playa                                                                                                      B. water

_____desert pavement

_____dune

_____inselberg

_____pediment

 

ANSWER:     B, B, A, A, B, B

 

CRITICAL THINKING

 

60. Since most deserts have internal drainage, why are there through-flowing streams such as the Nile, Niger, Indus, Colorado rivers in some deserts?

 

ANSWER:      The headwaters of these rivers are outside the desert and there is enough water to compensate for losses by evaporation and infiltration.

 

 

 

 

61. What are some of the human-caused factors which may be initiators of desertification?

 

ANSWER:     clearing of natural vegetation for crops/firewood, overgrazing, drilling water wells and irrigation, soil salinization, overpopulation

 

62. Briefly explain why sand is moved by wind before clay and silt during wind erosion.

 

ANSWER:      Sand grains protrude above the surface and are more easily caught by the wind, while clay and silt grains lie closer to the surface where there is a stationary layer of air, unless this is disturbed.

 

63. Briefly explain why there are extensive deposits of loess in China and in the Great Plains, Mississippi Valley and north-central states of the United States.

 

ANSWER:      The source for the loess deposits in China are the extensive deserts in Central Asia. The loess deposits of the Mississippi Valley and north-central states are derived from glacial outwash deposits.

 

64. Briefly explain how the geological conditions which have produced and deposited loess have determined the sites of the world’s major grain belts.

 

ANSWER:      Because loess derived soils are some of the most fertile in the world, the locations where large loess deposits have occurred have developed into some of the most productive farmland.

 

SHORT ANSWER

 

65. What is meant by the term “desertification”?

 

ANSWER:     the transformation of formerly productive lands into deserts

 

66. Which regions are most susceptible to desertification?

 

ANSWER:     those on the margins of existing deserts

 

67. It has been estimated that approximately how much land area is converted to deserts, per year, globally?

 

ANSWER:     70,000 square kilometers

 

68. Besides deserts, where is the wind a significant geologic agent?

 

ANSWER:     anyplace where exposure of sediment and soil is widespread/shorelines/plains

 

69. Why is wind unable to transport sediment with the same grain size competency as water?

 

ANSWER:     Air is less dense than water.

 

70. What size material is frequently carried as suspended load by wind?

 

ANSWER:     silt and clay

 

71. How does saltation by wind differ from that in streams?

 

ANSWER:     saltation by wind is self-perpetuating and generally moves smaller particles

 

72. How does the process of surface creep occur?

 

ANSWER:     Saltating sand grains strike larger particles and push them along the ground.

 

 

 

73. Which sized particles are usually the first to be set in motion by wind?

 

ANSWER:     sand

 

74. During sandstorms, how high can sand be lifted into the air?

 

ANSWER:     rarely more than 1 meter

 

75. Can the wind be a significant intercontinental agent of erosion and deposition? Explain.

 

ANSWER:     Yes. Wind can lift silt- and clay-sized particles high into the atmosphere, and transport this material large distances.

 

76. What are ventifacts?

 

ANSWER:     stones whose polished, pitted, faceted surfaces have been produced by wind erosion

 

77. What are yardangs?

 

ANSWER:     elongated, streamlined rock ridges in wind-dominated erosional areas

 

78. What is desert pavement?

 

ANSWER:     the close-fitting mosaic of pebbles, cobbles, and boulders covering the floor of many deserts and semi-arid regions

 

79. What are deflation hollows?

 

ANSWER:     shallow depressions created by differential wind erosion of surface materials

 

80. What are the two different types of important landforms created by wind deposition?

 

ANSWER:     dunes, loess

 

81. How do sand dunes migrate?

 

ANSWER:     by the saltation of sand on a dune’s windward side and collapse of the leeward slope

 

82. What factors affect the type of dune which forms?

 

ANSWER:     vegetation coverage, direction and velocity of wind, the amount of available sand

 

83. What are the four major dune types generally recognized?

 

ANSWER:     barchan, longitudinal, transverse, parabolic

 

84. What is loess?

 

ANSWER:     windblown deposits of silt and clay

 

85. What are the three main sources from which loess is derived?

 

ANSWER:     deserts, Pleistocene outwash deposits, floodplains in semi-arid regions

 

86. Why are loess-derived soils important?

 

ANSWER:     They are some of the world’s most fertile.

 

87. Which of the dune types is the most mobile?

 

ANSWER:     barchan

 

88. Besides the fact that they were formed by wind, what else can dunes preserved in the rocks tell us?

 

ANSWER:     the direction of prevailing winds when they were deposited

 

89. Briefly explain why loess can originate in, but is not deposited in, deserts.

 

ANSWER:     For loess to accumulate it must be stabilized by moisture and vegetation.

 

90. Air masses are set into motion by much the same mechanism as are plates. What is this mechanism?

 

ANSWER:     convection of heat

 

.91.         Equatorial regions receive the most heat, while polar regions receive the least. Therefore, what air pressures would you expect to be characteristic of these regions?

 

ANSWER:     low pressures in the equatorial regions, high pressures in the polar regions

 

92. What causes the Coriolis effect?

 

ANSWER:     the rotation of Earth

 

93. On average, how much rain do deserts receive per year?

 

ANSWER:     less than 25 cm per year

 

94. In what latitudes do most of the world’s deserts lie?

 

ANSWER:     low and middle latitudes

 

95. Briefly explain why most deserts develop in the mid-latitude dry climate zone.

 

ANSWER:      It is at this latitude that high pressure ridges form, and as air that is already dry descends, it becomes warmer, causing increased evaporation.

 

96. Briefly explain how a rainshadow desert forms.

 

ANSWER:      Air masses are forced to rise to move over mountains. As they do, they cool and moisture condenses and falls as precipitation. Upon descending the lee side of the mountain range this air mass is dry. It heats as it descends, and its aridity causes increased evaporation.

 

97. How is rock/desert varnish produced?

 

ANSWER:      by windblown iron and manganese dust or precipitates of microorganisms

 

98. What type of weathering is dominant in deserts?

 

ANSWER:      mechanical

 

99. What factors enhance water erosion in deserts?

 

ANSWER:      little vegetation cover, and the inability of dry sparse soil and regolith to rapidly absorb water

 

 

 

100. What is a common mode of mass wasting in deserts?

 

ANSWER:      mud flows

 

101. Sand covers approximately what percentage of the world’s deserts?

 

ANSWER:      25%

 

102. What is internal drainage?

 

ANSWER:      the type of drainage characteristic of most deserts, where streams dry up, and do not have enough water become integrated and reach outside their drainage areas

 

103. Why is chemical weathering insignificant in deserts?

 

ANSWER:      What little water is briefly present has little time to act as a solvent.

 

104. Why are flashfloods and sheetflows common in deserts?

 

ANSWER:      The lack of vegetation, relative lack of soil, abundance of regolith, and hardness of the soil surface prevents water from filtering into the soil.

 

105. How does the topography of the water table in deserts with through-flowing streams result in the restriction of much of the vegetation to the stream banks?

 

ANSWER:      Water tables in deserts tend to be located at great depth and not associated with streams. Very limited infiltration of water from streams, does, however, allow a zone of vegetation to develop along stream valleys.

 

106. What did the famous twenty-mule teams haul out of Death Valley?

 

ANSWER:      borax

 

107. How were the famous borax deposits of Death Valley formed?

 

ANSWER:      Borax was leached from volcanic deposits and deposited as lake sediment before the lakes evaporated.

 

108. What is a pediment?

 

ANSWER:      an erosional bedrock surface of low relief that slopes gently away from a mountain base

 

109. Briefly explain how mesas and buttes form.

 

ANSWER:      A nearly horizontal resistant layer of rock is breached by weathering and erosion, allowing the underlying less resistant layers to be rapidly eroded. The flat-topped steep-sided erosional remnants are mesas, and further erosion leaves the pillar-like structures called buttes.

 

110. What is a bajada?

 

ANSWER:      a broad alluvial apron formed by the coalescence of alluvial fans

 

111. What is a playa lake?

 

ANSWER:      a usually shallow, often saline, temporary lake in a desert

 

 

 

112. How does a playa form?

 

ANSWER:      by evaporation of a playa lake

 

113. Explain the ways in which alluvial fans and deltas are similar.

 

ANSWER:      Both are deposited by running water which abruptly encounters a dramatic reduction in velocity, and both spread laterally as a fan-shaped deposit.

 

114. Why are large alluvial fan deposits of importance to human residents of deserts?

 

ANSWER:      They can be a source of otherwise scarce groundwater, and the outer edges can have soil for farming.