Earth: An Introduction to Physical Geology, 11e (Tarbuck)
Chapter 19 Deserts and Winds
19.1 Multiple-Choice Questions
1) Traditionally, a region is defined as a desert if it receives less than ________ inches of rain
per year.
A) 10
B) 5
C) 15
D) 22
2) From a climatological perspective, a region is a desert if ________.
A) Yearly precipitation exceeds evaporation
B) Yearly precipitation is equal to evaporation
C) Yearly precipitation is less than evaporation
3) A true desert is defined by a lack of what substance?
A) Oxygen
B) Plant life
C) Rocks
D) Water
4) Most dry lands exist between ________ degrees on either side of the Equator.
A) 50-60
B) 35-40
C) 20-30
D) 0-10
5) Which of the following statements about deserts is true?
A) Although rainfalls are infrequent, erosional and deposition related to water is important in
deserts
B) Deserts are located where there are ascending air masses and low atmospheric pressure
C) Deserts are defined by their sand content
D) Deserts are always located in hot, humid coastal areas
6) What percentage of the Earth’s land area is covered by deserts and steppes?
A) 14%
B) 30%
C) 9%
D) 50%
7) Which of the following areas are known for their rainshadow deserts?
A) North central Africa
B) South America west of the Andes
C) Central Iran
D) The dry valleys of eastern California and Nevada
8) Which of the following statements supports the fact that deserts lack thick deposits of soil?
A) Low temperatures and high soil moisture contents accelerate chemical weathering
B) Warm temperatures and high soil moisture contents accelerate chemical weathering
C) Warm temperatures and low soil moisture contents promote rapid mechanical weathering
D) Temperature has no effect on rock weathering
9) In a desert environment, in which area would surface water infiltrate into the local
groundwater system most effectively?
A) Playa lakes with thick mud bottoms
B) Streams flowing across an alluvial fan
C) Streams flowing across bare bedrock
D) Steep-walled mountain streams
10) What is the definition of an ephemeral stream?
A) A distributary channel on a stream delta
B) A stream that meanders back and forth across a valley
C) A stream that has interweaving channels and is choked with sediment
D) An intermittent stream that only has water after specific episodes of rain
11) Which of the following is not another name for an ephemeral stream?
A) Arroyo
B) Wadi
C) Pluvial
D) Wash
12) Which of the following landforms is carved from solid rock?
A) Playa
B) Inselberg
C) Alluvial fan
D) Bajada
13) Which of the following can contain large quantities of evaporite minerals such as borate and
halite?
A) Playa
B) Inselberg
C) Alluvial fan
D) Bajada
14) Which location in the United States contains examples from all three stages of desert
landscape evolution?
A) Rocky Mountains
B) Ohio River Valley
C) Marathon Uplift
D) Basin and Range Province
15) ________ refers to the bouncing motion sands will display when transported by moving
water or wind.
A) Yardang
B) Saltation
C) Deflation
D) Slithering
16) Which size(s) of sediment makes up most of wind’s suspended load?
A) Sand
B) Sand and silt
C) Silt
D) Silt and clay
17) Why is it so difficult for wind to pick up clay-sized particles?
A) They are too large for the wind to carry
B) The wind has a near-zero velocity closest to the surface and can’t pick them up
C) The clay particles are often buried under larger sediments
D) There is too much clay to carry
18) Which one of the following statements about landforms is correct?
A) Alluvial fans typically rim desert valleys
B) Playas form on high cuestas in arid areas
C) Inselbergs are composed of coarse sands and gravels
D) Inselbergs are found in low, circular depressions
19) Which set of characteristics would best fit a geologically recent fault block mountain uplift?
A) Large, broad bajadas with many inselbergs
B) Small playas and large alluvial fans
C) Flat upland surface, steep slopes, and small alluvial fans
D) Extensive playas ringed by large sand dunes
20) Which mechanical weathering process will be most common in an arid environment?
A) Salt wedging
B) Abrasion
C) Root wedging
D) Exfoliation
21) What process creates desert blowouts?
A) Moving water
B) Evaporating lake
C) Herd animals pawing at the ground
D) Wind
22) There is no one maximum depth for desert blowouts. They vary in depth depending on
conditions present at the location. What controls the depth of all blowouts?
A) Force of the moving wind
B) Velocity of water eddy
C) Elevation of water table
D) Amount of water available for dissolution of underlying materials
23) A(n) ________ is a smooth, polished rock that has been abraded by the wind.
A) Blowout
B) Bajada
C) Inselberg
D) Ventifact
24) Which of the following locations has seen persistent and well-documented desertification
over the last fifty years?
A) Oklahoma and Texas on the east side of the Chihuahuan Desert
B) The Sahel region on the southern margin of the Sahara Desert
C) Central and southern Great Plains in the United States
D) Central Asian steppes in southern Russia, Ukraine, and Kazakhstan
25) What is a yardang?
A) A wind-sculpted landform oriented parallel to the prevailing wind, often narrow at the base
B) An erosional rock remnant surrounded by deep sediment deposits
C) A glacially sculpted boulder with striations on the polished side
D) A pit worn into a rock by circular currents of flowing water
26) Glacial rock flour carried by blowing winds is referred to as ________.
A) Deflation deposits
B) Loess
C) Eolian sands
D) Alluvium
27) The central United States is covered with extensive deposits of loess. Where did this loess
come from?
A) Alluvium deposited during major floods
B) Rock flour from the braid plains of Pleistocene glacial streams and rivers
C) Decomposing sandstone from the St. Peter Sandstone
D) Weathering and erosion of western mountains
19.2 True/False Questions
1) A true desert is defined by how hot it is.
2) The world’s largest desert is Antarctica.
3) The world’s driest desert is the Atacama Desert in Peru.
4) Middle-latitude deserts and steppes are more extensive in the Northern Hemisphere than in the
Southern Hemisphere.
5) Salt wedging is a weathering process that is more common in humid areas than arid.
6) Streams in arid areas generally lack tributaries.
7) Wind is the most powerful agent of erosion in a desert.
8) Rates of weathering in deserts are higher than those in humid areas because, even though there
isn’t a great deal of precipitation, it is usually heavy when it does fall.
9) Interior drainage, such as the drainage that develops in deserts, does not flow out of the desert.
10) Inselbergs are generally associated with an early-stage desert landscape.
11) The Basin and Range Province of the American southwest is known for the diversity of its
arid region landforms.
12) Saltating sand grains are rarely carried more than one meter above the surface in normal
circumstances.
13) Sandstorms should be more accurately referred to as siltstorms because most sediment
carried by wind for long distances is actually silt-sized.
14) Due to the lack of chemical weathering, there is a great deal of clay-sized sediment in desert
areas.
15) Wind in arid regions produces more erosional landforms than depositional landforms.
16) Wind alone is enough to create a ventifact.
19.3 Short Answer Questions
1) Within water-deficient regions, two climatic types are recognized. What are they?
2) Circle the Correct Answer: (Mechanical / Chemical) weathering is most common in a desert
environment.
3) Streams in arid regions are generally small and die out before reaching the sea. Explain two
ways that streams lose water in this environment and why this loss occurs.
4) How was the Salt Pan at Death Valley created? What is the name of such a desert feature?
5) Fine particles such as clays and silts are often flat and platy in shape. Evaluate their ability to
be transported by wind based on this shape.
6) Why is erosion by wind more effective in an arid region than in a humid region?
7) The ________ was a period of drought in the 1930s in the United States that resulted in
significant dust storms blowing fine sediment for hundreds of miles.
8) What are the two primary sources for loess?
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19.4 Matching Questions
Match the location with the kind of desert it is. (Note: You may use some choices more than
once.)
A) Middle-Latitude Deserts and Steppes
B) Subtropical Deserts and Steppes
1) Atacama Desert
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 19.1 – Distribution and Causes of Dry Lands
Focus/Concepts: 19.1
Earth Science LO: 4.8 – Weathered and unstable rock materials erode from some parts of Earth’s
surface and are deposited in others.
2) Gobi Desert
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 19.1 – Distribution and Causes of Dry Lands
Focus/Concepts: 19.1
Earth Science LO: 4.8 – Weathered and unstable rock materials erode from some parts of Earth’s
surface and are deposited in others.
3) Eastern Washington State
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 19.1 – Distribution and Causes of Dry Lands
Focus/Concepts: 19.1
Earth Science LO: 4.8 – Weathered and unstable rock materials erode from some parts of Earth’s
surface and are deposited in others.
4) Southwestern United States
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 19.1 – Distribution and Causes of Dry Lands
Focus/Concepts: 19.1
Earth Science LO: 4.8 – Weathered and unstable rock materials erode from some parts of Earth’s
surface and are deposited in others.