Deck 15: Eolian Processes and Arid Landscapes

Question 1

Compared to other geomorphic agents,wind is ________ effective at eroding and transporting materials because its density is ________ than that of other geomorphic agents.

A)more more
B)more less
C)less more
D)less less
E)equally more

Answer 1

D

Question 2

Which two processes create desert pavement?

A)deflation and sheet wash.
B)deflation and abrasion.
C)abrasion and sheet wash.
D)deflation and saltation.
E)saltation and abrasion.

Answer 2

A

Question 3

Desertification is a global political issue because

A)local poverty and inability to change subsistence agricultural practices is being exacerbated by the poleward shift of subtropical high pressure systems due to climate change.
B)climate change means that all of the surface of Earth is subject to increased temperatures and possible shift to desert conditions.
C)desert areas are all in Africa and there are adequate environmental policies to manage them.
D)low population numbers in desert areas mean that people in other areas will have to manage the arid lands.
E)there is an excellent database of arid lands,but the problem is not well understood.

Answer 3

A

Question 4

Which of the following terms is a correct reference to a desert pavement?

A)prairie
B)gravel mounds
C)sand seas
D)reg desert
E)tundra

Question 5

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

A)large
B)intermediate
C)small

Question 6

Wind is ________ effective at eroding and transporting materials compared to other geomorphic agents because ________.

A)more it reaches higher velocities
B)more it can carry more material
C)less it does not erode to base level.
D)less is less dense than other materials
E)equally although it is less dense,it has a greater capacity.

Question 7

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

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

Question 8

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 cohesionless.
D)their small size creates a wind shadow that prevents the wind from transporting them.
E)their shape reflects wind energy.

Question 9

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

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

Question 10

Which is true regarding the processes that create desert pavement?

A)it is produced by ablation.
B)it is produced by ice delivered cementing materials.
C)it is produced by wind removing sand particles from the surface.
D)it is produced by saltation.
E)it is produced by continuous high winds.

Question 11

Desert pavement refers to

A)specially constructed roadbeds in dry and hot regions.
B)surfaces of concentrated pebbles and gravels.
C)surfaces that evidently were not affected by the 1991 Persian Gulf War.
D)sand-covered surfaces.
E)roads in the Sahara desert.

Question 12

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.
E)slightly rough surfaces.

Question 13

The term 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.
E)the breakdown of rock material in place.

Question 14

For purposes of discussing eolian processes,the wind acts like a

A)solid.
B)gas.
C)plasma.
D)fluid.
E)liquid

Question 15

The often-sited work on eolian processes is The Physics of Blown Sand and Desert Dunes written by

A)William Morris Davis.
B)John Wesley Powell.
C)Ralph A.Bagnold.
D)Edward Abbey.
E)J)H.Mackin

Question 16

A 50 km · h⁻¹ wind blowing for 24 hours moves how much sand over 1m²

A)10 kg
B)50 kg
C)500 kg
D)1000 kg
E)2000 kg

Question 17

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.
E)is greater than ice,but less than water.

Question 18

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.
E)requires freezing temperatures

Question 19

The sandblasting action of wind-blown particles is called

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

Question 20

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
E)aggradation diminution

Question 21

Which is a problem with deserts and eolian features?

A)sand dune migration over human features at Nag's Head,N.C.
B)contraction of the Sahara desert northward
C)sand deflation from roads and towns in Kuwait due to the Gulf War
D)ORVs creating paths for animal migrations
E)flash floods depositing coarse material on desert pavements.

Question 22

The suspension of finer particles by wind over significant distances is a phenomenon known as

A)a yardang.
B)a dust storm.
C)saltation.
D)surface creep.
E)arroyo.

Question 23

Abrasion is usually confined to a zone which extends up to ________ above the ground.

A)1 cm
B)1 m
C)5 m
D)10 m
E)50 m

Question 24

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.
E)is directly related to the suspension of particles in the air.

Question 25

Removal of vegetation from a semiarid grassland environment is likely to lead to

A)deflation.
B)abrasion.
C)soil development.
D)deposition.
E)mass movement.

Question 26

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
E)suspended particles saltation.

Question 27

The smallest features shaped by individual saltating grains are

A)ripples.
B)dunes.
C)sand seas.
D)reg deserts.

Question 28

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

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

Question 29

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

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

Question 30

Once particle motion is initiated,subsequent motion can be maintained ________ because of the process of ________.

A)at lower wind velocities particle impact
B)at lower wind velocities deflation
C)only with higher wind velocities particle impact
D)only with higher wind velocities deflation
E)only with higher wind velocities movement suppression

Question 31

The impact of saltating particles acts to

A)initiate the movement of other particles.
B)suppress the movement of other particles.
C)aggrade surfaces.
D)roughen surfaces
E)create surface tension.

Question 32

Surface creep is responsible for ________ of the material in motion by wind.

A)0)2 percent
B)two percent
C)ten percent
D)twenty percent
E)forty percent

Question 33

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.
E)exact wind speed can be calculated from their spacing.

Question 34

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

A)groundwater.
B)field water capacity.
C)hygroscopic water.
D)ephemeral streams.
E)flash floods.

Question 35

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

A)sand
B)silt and clay
C)gravel
D)sand and gravel
E)sand and clay

Question 36

A depression created by deflation is known as a

A)playa.
B)bolson.
C)blowout.
D)structural basin.
E)arroyo

Question 37

Because air has a ________ density than water,saltating particles in an eolian environment strike one another with ________ force than do saltating particles in a stream.

A)higher more
B)higher less
C)lower more
D)lower less

Question 38

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 an increase in small animal populations.
C)it can initiate ablation.
D)it can initiate dune development.
E)ORVs have never been shown to cause measurable impacts on desert environments

Question 39

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.

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)30 percent
C)50 percent
D)70 percent
E)90 percent

Question 41

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
E)mountain slopes glacial regions.

Question 42

Which of the following is true of loess deposits?

A)they are principally composed of sands and gravels.
B)they are formed of fine-grained clays and silts.
C)they are found only in Antarctica.
D)they form only following glacial activity.
E)they are found only in Europe.

Question 43

A crescent-shaped dune with anchoring vegetation is called a

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

Question 44

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

A)barchan - abundant sand supply
B)transverse - limited sand supply
C)parabolic - vegetation controlled
D)crescentic - bidirectional wind
E)longitudinal - multi-directional wind

Question 45

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.
E)dome dune

Question 46

As regards the sides of a dune,which of the following is correctly matched?

A)windward - avalanche slope
B)windward - angle of repose
C)leeward - avalanche slope
D)stoss -angle of repose
E)brink - angle of repose

Question 47

Significant loess deposits are found in the

A)Mississippi delta.
B)Cascade Mountains,Washington state.
C)Ukraine in the former Soviet Union.
D)Great Lakes lowlands.
E)north of the Arctic Circle.

Question 48

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

A)5°.
B)10°.
C)34°.
D)65°.
E)85°.

Question 49

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
E)84 percent

Question 50

The Grand Erg Oriental is an example of a

A)gibber plain.
B)reg desert.
C)sand sea.
D)sand desert in China.
E)desert pavement

Question 51

Which of the following is true of loess?

A)it consists of fine-grained clays and silts and can form vertical cliffs.
B)it makes for poor quality agricultural land.
C)it is derived only from glacial outwash plains or deserts.
D)it has low binding strength.
E)it is found in very few,small locations globally.

Question 52

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

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

Question 53

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 54

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 55

Because linear dunes are formed from ________ winds,they have ________.

A)unidirectional one slipface
B)unidirectional two slipfaces
C)bidirectional one
D)bidirectional two slipfaces
E)multidirectional four slipfaces

Question 56

The spatial distribution of Earth's dry regions are attributable to

A)subtropical high-pressure cells between 15° and 35° N and S latitudes.
B)rain shadows windward of mountain ranges.
C)the equatorial low-pressure region and the ITCZ.
D)proximity to moisture-bearing air masses.

Question 57

Relatively small dunes that are crescentic in shape are termed ________ dunes.

A)barchan
B)star
C)longitudinal
D)seif
E)dome

Question 58

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 59

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
E)brink

Question 60

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

A)leeward side
B)windward side
C)freedune side
D)stoss
E)topside

Question 61

Which of the following is true of alluvial fans?

A)they are poor sources of groundwater.
B)they frequently occur in eastern North America.
C)the largest sized sediment is found near the top of the fan,and the smallest near the bottom.
D)they are erosional features.
E)they develop because of the continuous flow of stream water over their surface.

Question 62

A wadi would make a ________ camp site because ________.

A)good it is filled with soft sediments
B)good cool air will drain into it at night
C)poor all sorts of threatening creatures live there
D)poor flash floods can occur without warning
E)good water drains away easily

Question 63

Which of the following is true?

A)Playas are located in horsts.
B)Bajadas are located in horts.
C)Bolsons run from graben to graben
D)Horsts are found in bolsons.
E)Alluvial fans can coalesce to form bajadas.

Question 64

Cross-stratification refers to

A)the orientation of ripples.
B)overlapping alluvial fans.
C)depositional features on pediments.
D)lithified slipfaces.
E)dune surfaces.

Question 65

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
E)nickpoint terrace

Question 66

Which of the following is correct regarding the Basin and Range Province?

A)the ridges and valleys are a product of intense folding.
B)the present landscape is a sequence of sills and dikes.
C)the area covers 800 000 in the western United States.
D)it is characterized by a series of overthrust folds.

Question 67

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

A)pediment
B)bajada
C)playa
D)yardang
E)desert pavement

Question 68

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

A)gully
B)arete
C)arroyo
D)sastrugi
E)rill

Question 69

Playas are likely to contain ________ concentrations of salt because ________.

A)high of evaporation of water containing dissolved salts
B)high salt domes are exposed when playas are formed by erosion
C)low large amounts of fresh groundwater dilute the salt concentration
D)low large amounts of freshwater runoff from surrounding mountains dilutes the salt concentration

Question 70

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 71

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.
E)there is no water supply.

Question 72

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.
E)wadi.

Question 73

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

A)rugged and hard-edged lack of chemical weathering
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 74

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(n)

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

Question 75

The major erosional force in the desert is

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

Question 76

Which of the following basin and range features would you find in a basin?

A)butte
B)playa
C)fan delta
D)sill
E)horst

Question 77

Which of the following is another name for an alluvial fan?

A)arroyo
B)wadi
C)foggara
D)gibber plain
E)seif

Question 78

Cross-stratification can be used by geologists to

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

Question 79

The Basin and Range Province was formed by

A)earthquakes.
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)landslides.
E)volcanic activity.

Question 80

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).