Deck 12: Wind Processes and Desert Landscapes

Question 1

The sandblasting action of wind-blown particles is called

A) deflation.
B) abrasion.
C) saltation.
D) grinding.

Answer 1

B

Question 2

The term $\underline {\text { eolian } }$ refers to

A) stream-related processes.
B) glacial processes in areas outside the polar regions.
C) erosion, transportation, and deposition by the wind.
D) weathering and mass movement in humid regions.

Answer 2

erosion, transportation, and deposition by the wind.

Question 3

A desert pavement surface is associated with which of the following types of deserts?

A) erg
B) sand sea
C) reg
D) polar desert

Answer 3

C

Question 4

The impact of saltating particles acts to

A) initiate the movement of other particles.
B) suppress the movement of other particles.
C) abrade surfaces.
D) both A and C
E) both B and C

Question 5

A depression created by deflation is known as a

A) playa.
B) bolson.
C) blowout depression.
D) structural basin.

Question 6

The ability of the wind to move materials

A) exceeds that of other transporting agents, such as water and ice.
B) is small compared to other transporting agents, such as water and ice.
C) is greater than that of water because of the higher density of air compared to water.
D) increases with decreased wind speed.

Question 7

Rocks that appear pitted and grooved, and sometimes polished smooth by eolian processes, are termed

A) ventifacts.
B) yardangs.
C) desert pavements.
D) alluvium.

Question 8

The removal and lifting of individual loose particles by the wind is termed

A) deflation.
B) abrasion.
C) saltation.
D) deposition.

Question 9

Which of the following can result from ORV (off road vehicle) use in a desert environment?

A) It can cause destruction of vegetation through both direct and indirect effects.
B) It can lead to a reduction in small animal populations.
C) It can initiate erosion.
D) All of the above can occur.
E) None of the above-ORV's have never been shown to cause measurable impacts on desert environments.

Question 10

Desert pavement refers to

A) specially constructed roadbeds in dry and hot regions.
B) surfaces of concentrated pebbles and gravels that are produced by particle removal and water-delivered cementing materials.
C) surfaces that evidently were not affected by the 1991 Persian Gulf War.
D) sand-covered surfaces.

Question 11

Weathering that occurs by water in the desert is associated primarily with

A) groundwater.
B) field water capacity.
C) hygroscopic water.

Question 12

The lowering of the land surface by the lifting and removal of material is termed ________, whereas the grinding of rock surfaces with a "sandblasting" action is ________.

A) abrasion; deflation
B) deflation; abrasion
C) saltation; abrasion
D) mass wasting; deflation

Question 13

Abrasion is usually confined to a zone that 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)

Question 14

Which of the following surface conditions would limit the effectiveness of wind as an erosional agent?

A) Surface materials that are noncohesive.
B) Surface materials consisting of clay-sized particles.
C) Surface materials that are dry.
D) Surfaces covered with little or no vegetation.

Question 15

Small particles are difficult for wind to move because

A) although they are small, they have a higher density than many of the larger sized particles in a desert environment.
B) they are aerodynamic.
C) they tend to be cohesive.
D) all of these
E) They are aerodynamic and cohesive only.

Question 16

The skipping and bouncing action of saltation accounts for

A) hydraulic lifting by air movements.
B) the transport of very small grains, smaller than 0.01 mm in diameter.
C) about 80 percent of wind transported particles.
D) little or no surface creep.

Question 17

Which of the following grain sizes is most readily moved by the wind?

A) large
B) intermediate
C) small

Question 18

What size material composes the dust in a dust storm that extends thousands of feet above the ground?

A) sand
B) silts and clays
C) gravels
D) sand, silts, and clays

Question 19

Elongated, streamlined ridges aligned parallel to the most effective wind direction are called

A) ventifacts.
B) yardangs.
C) desert pavements.
D) alluvial rock structures.

Question 20

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

Question 21

As deltas are depositional features of fluvial processes, so ________ are depositional features of eolian (wind) processes.

A) canyons
B) landslides
C) moraines
D) dunes

Question 22

Which of the following is false regarding loess?

A) It consists of fine-grained clays and silts and can form vertical cliffs.
B) It serves as good agricultural land.
C) It is derived from glacial outwash plains or deserts.
D) It has low binding strength.

Question 23

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.

Question 24

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

Question 25

Desert landscapes tend to be ________ in appearance because of the ________.

A) rugged and hard-edged; lack of water erosion
B) rugged and hard edged; type of resistant rock found in deserts
C) rounded and smooth; abrasion
D) rounded and smooth; type of nonresistant rock found in deserts

Question 26

The steepest side of a dune has a maximum angle of about

A) 5 degrees.
B) 10 degrees.
C) 34 degrees.
D) 65 degrees.

Question 27

Relative to dune movement and form, a dune's slipface forms on which side?

A) leeward side
B) windward side
C) freedune side
D) none of these

Question 28

A crescent-shaped dune with anchoring vegetation is called a

A) barchanoid ridge.
B) longitudinal dune.
C) parabolic dune.
D) reversing dune.

Question 29

Desert sand is usually composed of what mineral?

A) gypsum
B) quartz
C) dolomite
D) calcite

Question 30

Which of the following correctly describes a dry stream bed that is intermittently filled with water?

A) wash
B) wadi
C) arroyo
D) all of these

Question 31

Linear dunes and seif dunes are oriented

A) parallel to the wind.
B) perpendicular to the wind.
C) randomly in relation to wind direction.

Question 32

Which of the following dune types is incorrectly matched with the conditions necessary for its formation?

A) barchan - abundant sand
B) transverse - abundant sand
C) parabolic - vegetation controlled
D) crescentic - unidirectional wind

Question 33

Dry, arid climates occupy approximately what percentage of Earth's land surface?

A) 5 percent
B) 10 percent
C) 26 percent, and as much as 35 percent if all semiarid climates are considered
D) 65 percent

Question 34

A desert is an area in which

A) actual and potential evapotranspiration rates are roughly equal.
B) actual evapotranspiration rates exceed potential evapotranspiration rates.
C) potential evapotranspiration rates exceed actual evapotranspiration rates.
D) hot conditions exist throughout the year.

Question 35

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.

Question 36

A common crescent-shaped dune with horns pointed downwind is called a

A) transverse dune.
B) longitudinal dune.
C) seif dune.
D) barchan dune.

Question 37

A dune that is the mountainous giant of the sandy deserts is called a

A) transverse dune.
B) longitudinal dune.
C) parabolic dune.
D) star dune.

Question 38

An extensive area of sand and sand dunes is known as a/n

A) reg desert.
B) erg desert, or sand sea.
C) lag desert.
D) desert pavement.

Question 39

Which of the following is true of eolian ripples?

A) They are generally positioned parallel with the direction of the effective wind.
B) Their spacing is controlled by the moisture content of the sand.
C) They are oriented transversely, or at right angles, to the direction of the wind.
D) They form reg deserts made up of lag gravels.

Question 40

Active sand dunes and sandy deserts cover approximately what percentage of continental land between 30° N and 30° S latitude?

A) 10 percent
B) 50 percent
C) 70 percent
D) 90 percent

Question 41

Which of the following is false regarding alluvial fans?

A) They often serve as good sources of groundwater.
B) They frequently occur in the eastern U.S.
C) The largest sized sediment is found near the top of the fan, and the smallest near the bottom.
D) They are depositional features.

Question 42

The major erosional force in the desert is

A) wind.
B) the eolian process.
C) water and fluvial processes.
D) human activity.

Question 43

The Basin and Range Province was formed by

A) faulting.
B) tensional forces resulting from the fact that North America overrode a subducted ocean plate and was raised and stretched in the process.
C) compressional forces resulting from the collision of North America with a microplate, and which resulted in the creation of a folded mountain belt.
D) both A and B
E) both A and C

Question 44

A characteristic cone-shaped depositional feature in the desert that usually forms at the mouth of a canyon is known as a/n

A) bajada.
B) playa.
C) bolson.
D) alluvial fan.

Question 45

An exotic stream is

A) any river that flows from an arid region to one of adequate precipitation.
B) one involved in a particular historical event.
C) one whose entire course is in a desert region.
D) any river that arises in a humid region and then passes through to an arid region.

Question 46

Water is essential to the formation of a desert pavement.

Question 47

Which is false regarding the issues surrounding the use of Colorado River water?

A) The 1999-2008 drought is more severe than any seen in the historical record.
B) The Colorado River system is at 50% of capacity.
C) It would take 13 winters with normal snow pack to "reset" the Colorado River system.
D) Arizona's population grew 200% from 1990-2007, while Las Vegas grew 490% from 1985-2007.
E) Recent efforts have focused exclusively on reducing demand for water.

Question 48

Gibber plain, erg, and sand sea are regional names for the same type of desert surface.

Question 49

The wind has relatively minor effects on weathering and erosion.

Question 50

Which of the following can be found in the Basin and Range province?

A) horsts and grabens
B) faults
C) alluvial fans
D) pediments
E) all of these

Question 51

On the desert floor, at locally low elevations, an intermittently wet-and-dry flat area in a region of closed (interior) drainage is called a

A) wash.
B) wadi.
C) playa.
D) arroyo.

Question 52

Which of the following is true regarding the Colorado River?

A) Average flows today are roughly the same as when the Colorado River Compact was signed.
B) John Wesley Powell was a strong advocate for the current policy of river management.
C) Each party to the Colorado River Compact is entitled to an absolute amount of water, measured in millions of acre feet.
D) California has used only its alloted share of water from the Colorado River.

Question 53

Desertification is caused by

A) poor agricultural practices.
B) deforestation.
C) global climate change.
D) all of these

Question 54

Which of the following characterizations regarding Colorado River discharges and annual budgets is correct?

A) There are adequate average flows (1930-1980) in the system to meet the Compact (1923) and Mexican Water Treaty (1944) allotments.
B) The reservoirs that are in operation experience insignificant losses of water due to rock storage and evaporation.
C) The average flows in the second half of this century are more than double the budgeted amount.
D) The river system is about 3.5 million acre-feet in deficit from meeting annual budgets based on average flows from 1930 to 1980.

Question 55

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 B and C

Question 56

If several alluvial fans merge together, a ________ is formed.

A) pediment
B) bajada
C) playa
D) yardang

Question 57

Cross-stratification can be used by geologists to

A) locate water.
B) determine paleo-wind directions.
C) find ventifacts.
D) locate fault planes.

Question 58

Which of the following is true?

A) Playas are located in bolsons.
B) Bolsons are located in playas.
C) Bolsons and playas are geographically separate landforms that bear no topographic relationship to one another.

Question 59

Desertification is not caused by which of the following?

A) overgrazing
B) climate change
C) erosion and salinization of crop land
D) deforestation
E) all of the above cause desertification

Question 60

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).

Question 61

Loess deposits occur worldwide on every major continent other than Antarctica.

Question 62

Saltation accounts for the majority of material transported by the wind.

Question 63

Most of Earth's desert lands are covered by the familiar sand seas.

Question 64

Soils formed from loess tend to be infertile.

Question 65

The dust in a dust storm consists primarily of wind-blown sand.

Question 66

The Persian Gulf War resulted in the disruption and destruction of thousands of square kilometers of desert pavement.

Question 67

Alluvial fans often serve as groundwater sources.

Question 68

Barchan, transverse, and parabolic dunes are all types of crescentic sand dunes.

Question 69

Principal arid and semiarid lands only occur on the continental landmasses of the Northern Hemisphere.

Question 70

Much of desertification is due to human actions.

Question 71

The amount of Colorado River water allocated to various states was based on an overestimate of the typical average annual discharge; consequently, there is not enough water available to meet the allocation requirements.

Question 72

Active and stable sand regions occur on every major continent except Antarctica.

Question 73

A ventifact can be used to determine the dominant wind direction in an area.