Deck 15: The Work of Wind and Deserts

Question 1

What term describes the close-fitting mosaic of pebbles, cobbles, and boulders covering the floor of many deserts and semi-arid regions?

A)ventifact
B)desert pavement
C)longitudinal dune
D)yardang
E)barchan dune

Answer 1

desert pavement

Question 2

Wind velocities are greater than water velocities, and therefore, wind can carry more sediment than water.

Answer 2

False

Question 3

Loess is important because it ____.

A)is an important source of building material
B)is rich in important ore deposits
C)sometimes contains petroleum
D)makes fertile soil
E)is an important source of groundwater

Answer 3

makes fertile soil

Question 4

Wind erosion occurs by ____.

A)saltation only
B)abrasion only
C)deflation only
D)saltation and abrasion
E)abrasion and deflation

Question 5

What has been one consequence of desertification?

A)The rate of global warming is accelerating.
B)There are more droughts.
C)Environmental refugees have a greater area to settle.
D)Croplands and rangelands are less productive.
E)The Sahara is no longer a fertile savanna.

Question 6

Surface creep is a common type of mass wasting in deserts.

Question 7

The major topographic features of western United States deserts formed during the Pleistocene Epoch.

Question 8

Historical records indicate wind power has been harnessed by people for about 7,000 years.

Question 9

What are windblown deposits of silt and clay called?

A)dunes
B)loess
C)ventifacts
D)yardangs
E)till

Question 10

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

A)a few centimeters
B)about 50 centimeters
C)about one meter
D)about 10 meters
E)hundreds of meters

Question 11

The primary method of erosion in arid regions is ____.

A)wind
B)water
C)frost wedging
D)ventification
E)sedimentation

Question 12

What are elongated, streamlined rock ridges in wind-dominated erosional areas called?

A)ventifacts
B)barchan dunes
C)longitudinal dunes
D)yardangs
E)desert pavement

Question 13

Sand covers approximately 75 percent of the world's deserts.

Question 14

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

Question 15

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

Question 16

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

Question 17

All dunes originate in desert conditions.

Question 18

Thick deposits of loess form longitudinal desert dunes.

Question 19

What size of particle is usually the first to be set in motion by wind?

A)silt
B)clay
C)sand
D)pebble
E)boulder

Question 20

Silt and clay sized particles are carried in the wind's ____.

A)suspended load
B)saltation load
C)dissolved load
D)bed load
E)convection load

Question 21

Air flows from ____.

A)windy areas to non-windy areas
B)low pressure areas to high pressure areas
C)high pressure areas to low-pressure areas
D)the right in the Northern hemisphere
E)the top of the atmosphere to the bottom of the atmosphere

Question 22

Dunes that form when vegetation cover is broken by deflation and the dune tips point upwind are ____.

A)longitudinal
B)transverse
C)barchan
D)parabolic
E)beach

Question 23

Which statement about deserts is most accurate?

A)Evaporation exceeds precipitation in arid and semi-arid regions.
B)Loess deposits are common in deserts.
C)The geologic process at work in deserts are vastly different from those at work in humid regions.
D)Deserts do not have seasons, and they are uniformly hot year-round.
E)Deserts occur where atmospheric pressure is low.

Question 24

The Coriolis effect is caused by ____.

A)wind shear between water and the atmosphere
B)the axial tilt of Earth
C)the rotation of Earth
D)differences in air pressure in different regions
E)Milankovitch cycles

Question 25

What happens when an air mass rises over a mountain?

A)It rises, cools, and moisture condenses and falls as rain on the windward side of the mountain.
B)It rises, cools, and moisture condenses and falls as rain on the leeward side of the mountain.
C)It rises, warms, and moisture condenses and falls as rain on the leeward side of the mountain.
D)It rises, warms, and moisture condenses and falls as rain on the windward side of the mountain.
E)It rises, cools, and moisture evaporates and falls as rain on the windward side of the mountain.

Question 26

A(n)____ is an example of an erosional landform found in deserts.

A)dune
B)alluvial fan
C)mesa
D)bajadas
E)playa

Question 27

Imagine you are a geologist looking at a rock column. Which line of evidence would most strongly indicate that these rocks formed in a desert?

A)The presence of a dinosaur fossil
B)Cross-bedded silt and clay
C)Cross-bedded sand
D)A rusty orange color
E)Poorly sorted deposits of gravel, sand, silt and clay

Question 28

A broad alluvial apron formed by the coalescence of alluvial fans is called a(n)____.

A)alluvium
B)bajada
C)playa
D)plain
E)pediment

Question 29

What is an isolated mountain that rises from the flat plain of a desert called?

A)mesa
B)butte
C)inselberg
D)drumlin
E)yardang

Question 30

Deserts occur at ____ latitudes.

A)exclusively low
B)exclusively middle
C)exclusively high
D)mostly low and middle
E)mostly middle and high

Question 31

The advantage of using wind energy is that it ____.

A)is cheaper to produce energy with wind than with natural gas
B)can be harnessed from any location
C)is always "on," so there is not a need for back-up generation methods
D)allows for multiple uses of the land
E)kills fewer birds than buildings and power lines

Question 32

Weathering in the desert occurs primarily by ____ processes.

A)chemical
B)saltation
C)intermittent
D)alluvial
E)mechanical

Question 33

A(n)____ is an example of an depositional landform formed by running water that is found in deserts.

A)barchan dune
B)alluvial fan
C)mesa
D)butte
E)parabolic dune

Question 34

Which dunes are most mobile?

A)longitudinal
B)transverse
C)barchan
D)parabolic
E)beach

Question 35

Fan-shaped landforms that develop in deserts adjacent to highlands are known as ____ fans.

A)alluvial
B)bajada
C)playa
D)plain
E)pediment

Question 36

What is a common mode of mass wasting in deserts?

A)mud flows
B)rock fall
C)creep
D)slumps
E)slides

Question 37

____ is the world leader in wind energy production.

A)Canada
B)China
C)The United States
D)Egypt
E)Denmark

Question 38

Plants have adapted to deserts by ____.

A)growing in clumps
B)growing rapidly
C)growing deep tap roots
D)having long dormant years
E)developing soft stems and leaves

Question 39

The size, shape, and arrangement of dunes is affected by many factors, two of which are ____ and ____.

A)cross-bedding; sand supply
B)cross-bedding; vegetation
C)sand supply; wind direction
D)vegetation; saltation
E)vegetation; deflation

Question 40

The Coriolis effect causes wind to be deflected ____.

A)counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere
B)clockwise in the Northern hemisphere and counter-clockwise in the Southern hemisphere
C)counterclockwise in both hemispheres
D)clockwise in both hemispheres
E)randomly according to surface landforms

Question 41

A saline, temporary lake in a desert is known as a(n)____________________ lake.

Question 42

Why do desert streams rarely reach an ocean? What makes rivers such as the Nile, Colorado, and Rio Grande exceptions to the rule?

Question 43

____________________ zones are characterized by warm, dry, descending air.

Question 44

The most effective agent of erosion in the deserts is ____________________.

Question 45

Stones whose polished, pitted, faceted surfaces have been produced by wind erosion are called ____________________.

Question 46

The size of material that is frequently carried as suspended load by wind is ____________________ and ____________________.

Question 47

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

Question 48

The transformation of formerly productive lands into deserts is called ____________________.

Question 49

Explain how air masses are set into motion. You may find the use of drawings helpful.

Question 50

The drainage characteristic of most deserts, in which streams dry up and do not have enough water to become integrated and reach outside their drainage areas, is called ____________________ drainage.

Question 51

Desert winds are effective at producing erosional and depositional features. List one depositional feature and one erosional feature formed by wind in deserts and explain how each forms.

Question 52

What are the three primary sources of loess?

Question 53

Determine the wind direction in the accompanying figure. How do you know the wind is flowing in this direction?

Question 54

Deserts receive less than ______ centimeters of rain per year, on average.

Question 55

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

Question 56

____________________ convert the kinetic energy in wind into mechanical energy, which can then be used to generate electricity.

Question 57

Would it be surprising to find a desert at the North and South Poles, with latitudes of +90 and -90 degrees respectively? Why or why not?

Question 58

Gently sloping bedrock surfaces at the base of mountains that are typically covered by thin layers of debris, bajadas, or alluvial fans are called ____________________.