Quiz 7

Active sand dunes and sandy deserts cover approximately what percentage of continental land between 30°N and 30°S latitude? Question options: 10 percent 50 percent 70 percent 90 percent

10 precent

The steepest side of a dune has a maximum angle of about: Question options: 5° 10° 34° 65°

34°

Small particles are difficult for wind to move because: Question options: Although they are small, they have a higher density than many of the larger sized particles in a desert environment They are not cohesive They are not aerodynamic They are aerodynamic and cohesive

They are aerodynamic and cohesive

Soils formed from loess tend to be infertile. Question options: True False

False

For purposes of discussing aeolian processes, the wind acts like a Question options: Solid Gas Plasma Fluid

Fluid

The ability of the wind to erode materials: Question options: Exceeds that of other erosive agents, such as water and ice Is small compared to other erosive agents, such as water and ice Is greater than that of water because of the higher density of air compared to water Increases with decreased wind speed

Is small compared to other erosive agents, such as water and ice

Which side of a dune typically has a slope angle equal to that of the angle of repose for sand? Question options: Windward Leeward Stoss Top

Leeward

Relative to dune movement and form, a dune's slipface forms on which side? Question options: Leeward side Windward side Freedune side None of these choices; it is not associated with a particular sides

Leeward side

Linear dunes and seif dunes are oriented: Question options: Parallel to the wind Perpendicular to the wind Randomly in relation to wind direction Wind plays no role in the formation of those dunes

Parallel to the wind

Pebbles can be moved by ________ in a process known as ________ . Question options: Deflation; saltation Deflation; surface creep Saltating particles; deflation Saltating particles; surface creep

Saltating particles; surface creep

Which of the following terms is not a correct reference to a desert pavement? Question options: Gibber plain Lag gravels Sandseas Reg desert

Sandseas

Abrasion is usually confined to a zone which extends up to ________ above the ground. Question options: 1 cm (0.39 in) 1 m (3.28 ft) 5 m (16.4 ft) 10 m (32.4 ft)

1 m (3.28 ft)

Once particle motion is initiated, subsequent motion can be maintained ________ because of the process of ________. Question options: At lower wind velocities; particle impact At lower wind velocities; deflation Only with higher wind velocities; particle impact Only with higher wind velocities; deflation Only with higher wind velocities; movement suppression

At lower wind velocities; particle impact

Which of the following dune types is incorrectly matched with the conditions necessary for its formation? Question options: Barchan - abundant sand Transverse - abundant sand Parabolic - vegetation controlled Crescentic - unidirectional wind

Barchan - abundant sand

A depression created by deflation is known as a: Question options: Playa Bolson Blowout depression Structural basin

Blowout depression

Which of the following statements is correct regarding the erosion and transport of clay? Question options: Clay is easy to lift from a surface and is easy to keep suspended in the air Clay is difficult to lift from a surface but is easy to keep suspended in the air Clay is difficult to lift from a surface and is hard to keep suspended in the air

Clay is difficult to lift from a surface but is easy to keep suspended in the air

The removal and lifting of individual loose particles by the wind is termed: Question options: Deflation Abrasion Saltation Deposition

Deflation

Which two processes create desert pavement? Question options: Deflation and sheet wash Deflation and abrasion Abrasion and sheet wash Deflation and saltation Saltation and abrasion

Deflation and sheet wash

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 ________ . Question options: Abrasion; deflation Deflation; abrasion Saltation; abrasion Mass wasting; deflation

Deflation; abrasion

The term aeolian refers to: Question options: Stream-related processes Glacial processes in areas outside the polar regions Erosion, transportation, and deposition by the wind Weathering and mass movement in humid regions

Erosion, transportation, and deposition by the wind

The Sphinx in Egypt may have originally been a natural yardang that was subsequently shaped by people into its present form. Question options: True False

True

The wind has relatively minor effects on weathering and erosion. Question options: True False

True

Water is essential to the formation of a desert pavement. Question options: True False

True

Because air has a ________ density than water, saltating particles in an aeolian environment strike one another with ________ force than do saltating particles in a stream. Question options: Higher; more Higher; less Lower; more Lower; less

Lower; more

Which of the following is correct regarding loess deposits? Question options: They are principally composed of sand and gravels They are formed of fine-grained clays and silts They are found only in the United States They form only following volcanic activity

They are formed of fine-grained clays and silts