Honors Geology Test 2 - Chapter 17 Practice

The loess deposits in Europe and North America are thought to be derived mainly from

glacial and periglacial sources.

________ dunes form with their tips pointing downwind, usually in areas with limited sand supply and little to no vegetation.

Barchan

________ dunes are the largest in size and have multiple slipfaces produced by winds from varying directions.

Star

Which of the following is correct regarding loess deposits?

They are formed of fine-grained clays, silts and fine.

A ________ forms when individual alluvial fans coalesce.

bajada

A depression created by deflation is known as a

blowout.

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

fluid.

Which side of a dune typically has a slope angle equal to that of the angle of repose for sand?

leeward

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

leeward side

Windblown dust that accumulates into homogeneous deposits is known as

loess.

Which of the following is not a general shape upon which scientists classify dunes?

rectilinear

Dust storms, such as one from Arizona in 2013, are caused by downbursts associated with thunderstorms. Such storms are termed

haboobs.

The Basin and Range Province in the western United States is an example of a ________ landscape.

horst and graben

Which of the following terms is not a correct reference to a desert pavement?

sand seas

Large depressions, such as the Qattâra depression, formed as a result of

tectonic forces.

Which of the following areas is at highest (very high) risk of desertification?

the Sahel

________ are isolated remnants of resistant rock and products of long-term weathering and erosion.

Inselbergs

________ dunes form parallel to the prevailing wind, often extending for hundreds of kilometers in length.

Longitudinal

________ are flat-topped landforms with steep slopes resulting from differential weathering.

Mesas

In vegetated dune landscapes, ________ dunes form with their tips pointing upwind.

Parabolic

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

erg desert, or sand sea.

The term "eolian" refers to

erosion, transportation, and deposition by the wind.

The ability of the wind to move materials

is small compared to other transporting agents, such as water and ice.

Alluvial fans are formed as flowing water ________ as it leaves a constricted channel.

loses velocity

The smallest features shaped by individual saltating grains are

ripples.

An alcove in sandstone, such as that in the Cliff House at Mesa Verde, is indicative of which weathering process?

salt-crystal growth

The transport of small sand particles (0.07 to 0.20 mm) along the ground in a bouncing and skipping action is known as

saltation.

Factors that influence dry climates include all the following except

seasonal influence of the ITCZ.

The term used to describe rocks that are pitted, fluted, or polished from eolian erosion is

ventifacts.

The leading cause of decline in Lake Urmia is

water withdrawal.

Active dunes cover approximately ________% of Earth's deserts.

10

Saltation accounts for about ________% of sediment transport by wind.

80

The grinding and shaping of rock surfaces by the "sand blasting" action of particles captured in the air is termed

abrasion.

Which of the following is not considered a cause of desertification?

afforestation

Ephemeral channels that form in dryland climates in response to infrequent precipitation events are known as

arroyos.

Cone-shaped deposits of sediment often found at mouth of canyons in arid and semiarid climates are called

clastics.

The vast loess deposits in China are thought to be derived mainly from

deeply entrenched river channels.

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

deflation.

Dune migration on the Navajo Nation in the U.S. Southwest is an example of

desertification.

The general term for the land degradation in arid and semiarid regions characterized by expansions of deserts is

desertification.

Rocks of the same composition and structure found in the same area may have weathered at uneven rates due to a variety of factors. This is known as ________.

differential weathering

The Aral Sea, once one of the four largest lakes in the world, has steadily decreased since the 1960s on account of

diversion of incoming rivers for irrigation.

The sediment-accumulation hypothesis of desert pavement formation states

wind delivers fine particles that settle and wash downward as cycles of swelling and shrinking cause gravels to migrate upward.

The deflation hypothesis of desert pavement formation states

wind removes fine particles leaving large pebbles, gravels, and rocks, which become consolidated.

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

yardangs.

Arid and semiarid climates cover about ________ of Earth's surface.

one-third

A large region identifiable by several topographic or geological traits is known as a(n)

physiographic province.

A ________ is a dry bed of an ephemeral lake a dryland region.

playa.

________ are steep-sided landforms resulting from the weathering and mass wasting of mesas.

Buttes

Dryland rugged terrain of slopes dissected by rills and gullies are known as

badlands.

The coarsest materials, such as gravel, of an alluvial fan are found

near the mouth of the canyon.

The sliding and rolling along the ground of particles larger than 0.5 mm is known as

surface creep.

Desert pavement refers to

surfaces of concentrated pebbles and gravels.