Deck 18: Arid Region and Eolian Landforms

Question 1

Fluvial processes do more geomorphic work in arid lands than the wind does. ​

Answer 1

True

Question 2

Most desert streams are ephemeral. ​

Answer 2

True

Question 3

Over time, a butte may be eroded to form a mesa. ​

Answer 3

False

Question 4

A typical alluvial fan _____. ​

A)has its largest clasts near its apex
B)consists of loess
C)has a flat top
D)is deposited by eolian processes
E)is covered by ripples

Question 5

Most stream channels in desert regions have perennial flow. ​

Question 6

Stream systems of interior drainage _____. ​

A)have no tributaries
B)flow to a regional base level instead of ultimate base level
C)flow into the sea
D)are always perennial and meandering
E)are also known as exotic streams

Question 7

In arid regions, the wind is commonly able to pick up sand-sized particles and carry them high up in the air in suspension. ​

Question 8

Eolian transport can move sediment in suspension. ​

Question 9

The uppermost portion of an alluvial fan is called the bajada. ​

Question 10

Salt flats occur in playas. ​

Question 11

Exotic streams have base levels that are at higher elevation than their headwaters. ​

Question 12

The competence of moving air is generally limited to rock fragment that are sand sized or smaller.

Question 13

Playas _____.

A)never contain water
B)always contain water
C)consist of mesas and buttes
D)flow to the sea
E)may have surface salt deposits

Question 14

Badlands commonly form under natural conditions in humid climates. ​

Question 15

Areas of rugged, barren terrain dissected by a dense maze of steep gullies and ravines are called _____.

A)mesas
B)plateaus
C)pediments
D)badlands
E)loess

Question 16

Playas form wherever there is an inselberg. ​

Question 17

Isolated knobs of resistant bedrock that rise up from desert pediment surfaces are called _____. ​

A)bolsons
B)badlands
C)bajadas
D)inselbergs
E)base levels

Question 18

Alluvial fans are generally composed of uniform clay and silt. ​

Question 19

Transverse dunes form in areas with variable wind directions. ​

Question 20

Flash floods can be dangerous in the desert.

Question 21

Loess is _____. ​

A)commonly deposited on the upwind margins of deserts
B)composed primarily of gravel-size sediment
C)primarily transported by eolian suspension
D)primarily transported by surface creep
E)deposited out of solution from desert stream water

Question 22

What happens as streamflow exits the mouth of a canyon and onto an alluvial fan? ​

A)the stream widens, but flows at the same velocity
B)stream competence stays constant
C)stream capacity increases
D)the stream erodes more than it deposits
E)the stream widens and stream velocity decreases

Question 23

A close-fitting mosaic of gravel-sized stones that overlies a deposit of mostly finer-grained sediments in a desert is called _____. ​

A)desert pavement
B)a mesa
C)a ventifact
D)arroyo
E)an erg

Question 24

Desert bolsons would most likely have _____. ​

A)exterior drainage
B)plateaus
C)exotic streams
D)playas
E)karst topography

Question 25

Which list correctly orders the related features from smallest (listed first)to largest (listed last)? ​

A)plateau, mesa, butte
B)mesa, butte, plateau
C)butte, plateau, mesa
D)plateau, butte, mesa
E)butte, mesa, plateau

Question 26

Playas are _____. ​

A)ancient Pleistocene shorelines representing a past, more humid climate
B)eolian depositional landforms
C)flat because of resistant caprocks
D)dry stream channels that occasionally see flowing water
E)flat because of the movement of water and sediment by wind

Question 27

In Nevada, playas are frequently found in _____. ​

A)dune blowouts
B)basins between fault-block mountains
C)glacially carved valleys
D)mesas
E)parabolic dunes

Question 28

Caprocks are _____. ​

A)resistant rock layers that form the upper surface of mesas and buttes
B)a crust of salt crystals accumulating on the surface due to evaporating groundwater
C)hat-shaped rocks on top of thin, rock pedestals
D)landforms created by eolian erosion
E)areas of bedrock covered over by sand dunes

Question 29

Besides deserts, sand dunes are also commonly found in what environment? ​

A)karst regions
B)glacial regions
C)tropical rainforest regions
D)permafrost regions
E)coastal regions

Question 30

Where could you generally find rich soils with the potential to be transformed into productive agricultural lands in arid regions? ​

A)mesas
B)buttes
C)playas
D)washes
E)piedmont alluvial plains

Question 31

Wind-blown dust-sized particles of silt and clay can settle out to form thick blankets of sediment called _____ that may cover or bury the existing topography over widespread areas. ​

A)barchans
B)seif
C)deflation hollows
D)loess
E)clay pan

Question 32

Stabilized sand dunes _____. ​

A)have only been found on Mars
B)are protected from erosion by a surface salt crust
C)are protected from erosion by a surface clay pan
D)are anchored by yardangs
E)are normally stabilized by vegetation

Question 33

Longitudinal dunes are _____. ​

A)oriented parallel to the average wind direction
B)a type of barchan dune
C)a type of star dune
D)crescent-shaped dunes with arms that point upwind
E)only formed out of ice and snow

Question 34

Washes, or arroyos, are a type of _____. ​

A)stabilized sand dune
B)playa
C)stream channel with ephemeral flow
D)crescent-shaped sand dune
E)wind-eroded rock

Question 35

Large sand grains too heavy to be lifted into the air are pushed forward along the ground surface by the impact of bouncing grains in a process called _____. ​

A)ventifaction
B)debris flow
C)saltation
D)suspension
E)surface creep

Question 36

The world's desert regions _____. ​

A)have always had arid climates
B)are 99 percent covered by active sand dunes
C)are fragile environments
D)have no vegetation
E)have no topographic relief

Question 37

Compared to sandstorms, dust storms _____. ​

A)involve gravel-sized sediment
B)are moved by running water
C)carry smaller particles
D)carry ice instead of rock particles
E)carry sediment closer to the ground

Question 38

Barchans _____. ​

A)are a type of longitudinal dune
B)have slip faces oriented parallel to the average wind direction
C)have arms that point downwind
D)are typically stabilized by vegetation
E)are composed of gravel

Question 39

Desert landforms referred to as fans can be made by _____. ​

A)streams and debris flows
B)salt weathering and the wind
C)dune migration and rockfall
D)groundwater evaporation and weathering
E)solution and abrasion

Question 40

One possible factor that produces desert pavement is _____. ​

A)playa evaporation
B)mass wasting
C)deflation
D)base level changes
E)dune stabilization

Question 41

A(n)_______________ is a wind-sculpted, aerodynamically shaped remnant ridge left behind after the surrounding material has been eroded by abrasion. ​

Question 42

Wind blowing fast enough or with enough turbulence over an area of loose sediment is able to pick up and remove small fragments of rock in a process called _______________.

Question 43

How do alluvial fans form? ​

Question 44

A(n)____________________ stream originates in a humid region but flows across a desert region with enough discharge to reach the sea. ​

Question 45

Why are washes prone to flash floods? ​

Question 46

Particles that are too large to be carried in eolian suspension are bounced along the ground as part of the bed load in the transportation process of _______________.

Question 47

Playas that receive most of their water from surface runoff typically have a smooth clay surface, sometimes called a(n)_______________, that is hard when dried out by the desert sun but extremely gooey and slippery when wet. (two words)

Question 48

In eolian _______________, particles already being transported by the wind strike rocks or sediment and break off or dislodge additional rock fragments. ​

Question 49

Name a type of sand dune that could form in each of these conditions: an area with abundant sand supply and winds that blow from a constant direction, an area with bidirectional winds blowing from neighboring quadrants (such as northwesterly and southwesterly), and an area with winds that blow from varying directions. ​

Question 50

A rock that has been trimmed back to a smooth slope on one or more sides by sandblasting is called a(n)_______________. ​

Question 51

A(n)_______________ dune is a crescent-shaped dune with arms that are stabilized by vegetation and point unwind.

Question 52

Dunes that have a pyramidal shape with ridges of sand radiating out from a high center point are called _______________ dunes. ​

Question 53

If the vegetation cover on a stabilized dune is breached, perhaps from damage by range animals or off-road vehicles, the wind can then remove some of the sand, creating a depression called a(n)_____.

Question 54

A coalesced apron of alluvial fans along the base of desert mountains is called a(n)_______________. ​

Question 55

How do sand dunes migrate? ​

Question 56

How is a pediment different from an alluvial fan? ​

Question 57

Desert basins of interior drainage surrounded by mountains are called _______________. ​

Question 58

Through additional erosion of the caprock from all sides, a mesa can be reduced to a(n)_______________.

Question 59

The steep downwind slope of a dune that lies at the angle of repose is known as the _______________. (two words)

Question 60

Landforms that are created by wind are called _______________ landforms. ​