Quiz 19: Winds and Deserts

Eolian processes are powered by A)glaciers. B)ocean currents. C)streams. D)wind.

Which of the following statements is true? A)Air flows and stream flows are mostly laminar. B)Air flows are mostly laminar; stream flows are mostly turbulent. C)Air flows are mostly turbulent; stream flows are mostly laminar. D)Air flows and stream flows are mostly turbulent.

For the same velocity,why is air flow more turbulent than water flow? A)because air has a lower density than water B)because air has a lower viscosity than water C)because air is less confined by solid boundaries than water D)all of the above

From what direction do the trade winds in the tropics blow? A)east B)north C)south D)west

In the temperate zones of Earth between 30 and 60 latitude,the prevailing winds come from the A)east. B)north. C)south. D)west.

Martian dust storms are a major problem for many of the rovers that have roamed the planet surface.Which one of following rovers would you expect to be least affected by the Martian dust? A)Opportunity B)Curiosity C)Spirit D)Sojourner

Due to the Coriolis effect,any large-scale current of air or water is deflected to the _______ in the northern hemisphere and to the _______ in the southern hemisphere. A)left; left B)left; right C)right; left D)right; right

Which of the following is an important source of dust? A)volcanic dust from eruptions B)clay minerals from soils C)organic sources,such as charcoal,pollen,and bacteria D)all of the above

Why are streams able to move larger particles than wind? A)Air has a lower density and viscosity than water. B)Air does not obey the same laws of motion as water. C)Air moves at lower velocities than water. D)Air impedes the bounding movements of saltation.

The amount of windblown material that wind can carry does not depend on the A)particle size. B)surface material. C)temperature. D)wind strength.

For how long did fine-grained dust particles from the eruption of Mount Pinatubo remain in the atmosphere? A)several days B)several weeks C)several months D)several years

Which of the following processes does not increase the amount of dust in the atmosphere? A)agriculture B)deforestation C)erosion D)precipitation

Most windblown sand consists of A)calcite. B)feldspar. C)gypsum. D)quartz.

Why does volcanic dust tend to travel farther than wind-blown dust derived from the continents? A)because volcanic dust is erupted high into the atmosphere B)because volcanic dust is less dense than dust derived from the continents C)because volcanic dust is composed of quartz,whereas dust derived from the continents is composed of feldspar D)all of the above

Which of the following retards deflation? A)construction B)motor vehicles C)plowing D)vegetation

How do ventifacts form? A)by dissolution by dew B)by the breaking apart of rocks along cracks C)by sandblasting D)by slow chemical weathering

What type of environment yields quartz sand grains that are rounded and frosted? A)an eolian environment B)an oceanic environment C)a glacial environment D)a stream environment

What is the primary cause of frosting present in the surface of quartz sand grains in the desert? A)abrasion by air currents B)dissolution by dew C)chemical reaction with feldspar grains D)reactions with other sand grains

How does desert pavement form? A)by intense chemical weathering B)by stream erosion C)by intense mechanical weathering D)by wind erosion

Which of the following is a coarse,gravelly ground surface that results from the removal of fine-grained particles by wind erosion? A)alluvial fan B)desert pavement C)pediment D)talus slope

Which of the following processes describes the gradual erosion of the ground surface by wind? A)deflation B)desertification C)solifluction D)subsidence

Why do sand grains saltating in air "jump" higher than sand grains saltating in water? A)because air flow is more laminar than water flow B)because air is denser than water C)because air is less viscous than water D)because air is warmer than water

The cross beds exposed in an eolian sandstone dip to the west.During the deposition of the sand,the prevailing winds were probably from the A)east. B)north. C)south. D)west.

Sand will accumulate _______ of a boulder. A)mostly on the leeside (downwind) B)mostly on the windward side (upwind) C)equally on the leeside and the windward side D)neither on the leeside nor on the windward side

Pediments are A)small lakes that dry up in the desert. B)dry washes. C)mountain remnants buried in sand. D)a network of stream channels buried in the sand.

What type of sedimentary deposit results from the settling of fine-grained particles from a dust cloud? A)loess B)playa C)pediment D)sand dune

During erosion,loess tends to break off A)in horizontal layers. B)along irregular cracks. C)in vertical sheets. D)slowly,grain-by-grain.

The loess deposited in the Upper Mississippi Valley was derived primarily from A)coastal sand dunes. B)glacial deposits. C)desert regions lying to the west. D)volcanic dust.

If the North American plate suddenly changed direction and headed due south,then which region of North America would be most prone to desertification? A)Northern California B)the northern Great Plains C)the Great Lakes region D)the Eastern Seaboard

Ergs are A)eolian deposits similar to alluvial fans. B)a type of rock varnish. C)a particularly shaped sand dune. D)large fields of dunes.

Which of the following is a crescent-shaped dune? A)barchan B)loess C)pediment D)transverse

Long wavy sand ridges that lie perpendicular to the prevailing wind are called A)barchan dunes. B)blowout dunes. C)linear dunes. D)transverse dunes.

Sand dunes behind beaches are typically A)barchan dunes. B)blowout dunes. C)linear dunes. D)transverse dunes.

Long sand ridges that are more or less parallel to the prevailing wind are called A)barchan dunes. B)blowout dunes. C)linear dunes. D)transverse dunes.

How much of Earth's land area is covered by arid regions? A)5% B)20% C)50% D)80%

Which of the following best explains why the Sahara Desert of Africa exists? A)The Sahara Desert lies in the rain shadow of coastal mountains. B)The Sahara Desert lies near 30N latitude. C)The Sahara Desert lies thousands of kilometers from the ocean. D)The sandy soil of the Sahara Desert drains so quickly that vegetation is unable to grow.

Which of the following statements is false? A)Deserts form under virtually stationary areas of low atmospheric pressure. B)Deserts form far inland where air has already lost its moisture through precipitation. C)Deserts form where air is so cold only small amounts of moisture can precipitate. D)Deserts form where moisture-bearing winds are blocked by mountain ranges.

Which of the following best explains why the Great Basin and Mojave deserts of western North America exist? A)The two deserts lie in the rain shadow of coastal mountains. B)The two deserts lie in the trade winds. C)The two deserts lie near the equator. D)The two deserts lie thousands of kilometers from the ocean.

Over the past 20 million years,the interior of Australia has changed from a moist,humid climate to a desert.Why? A)because plate collisions have built mountains near the coastline that block moisture-bearing winds from the continent's interior B)because Australia has moved northward into an arid,subtropical zone C)because Australia has moved southward out of the path of the more humid trade winds D)because the continent has grown through volcanic activity,making the interior too far away from moisture-bearing winds

Which of the following is not a cause of desertification? A)cattle grazing B)climate change C)irrigation D)latitude changes caused by plate tectonics

Radar imaging from the space shuttle Endeavor has provided evidence that the Sahara Desert A)has always been an arid environment. B)was once a tropical region,with many different types of vegetation. C)once had an extensive system of river channels,which are now dry. D)has sand dunes in excess of 300 m in height.

Why does much of a desert's surface consist of sand,gravel,and rock rubble? A)because clay minerals form slowly in a desert environment B)because wind blows away clay and soil before it can accumulate to great thickness C)because vegetation is sparse and cannot prevent erosion of soil D)all of the above

Desert varnish is composed of all of the following,except A)carbonate minerals. B)clay minerals. C)iron oxides. D)manganese oxides.

What causes most of the erosion in deserts? A)groundwater B)streams C)thermal cycling D)wind

What minerals are responsible for the orange-brown colors of weathered surfaces in the desert? A)carbonates B)framework silicates C)iron oxides D)sulfates

Which of the following best describes the deposit left by a flash flood? A)a combination of desert pavement and loess B)a flat deposit of coarse debris C)channel,levee,and floodplain deposits D)thin deposits of evaporites

How much of the Sahara Desert is covered with sand and sand dunes? A)approximately 1% B)approximately 10% C)approximately 50% D)approximately 90%

Temporary lakes that accumulate in arid desert basins are called ______ lakes. A)eolian B)erg C)playa D)wadi

Small desert valleys are called wadis in the Middle East and __________ in the western United States. A)dry washes B)ergs C)loess D)pediments

Which of the following is a broad,gently sloping platform of bedrock that is left behind as a mountain front eroded in the desert? A)alluvial fan B)erg C)mesa D)pediment

Most of the superficial deposits found on Mars were formed by _______ processes. A)glacial B)marine C)eolian D)volcanic

Scientists' ability to study the Martian surface is sometimes inhibited by A)solar winds. B)dust storms. C)radio waves. D)atmospheric clouds.

Most of the world's deserts occur in the A)regions around the north and south pole. B)regions where the westerlies blow. C)regions north and south of the equator knows as the tropics. D)regions of elevation above 10,000 meters.

What factor contributes to the formation of deserts? A)high atmospheric pressure B)extremely low amounts of rainfall C)low humidity D)all of the above

Particles that can be carried in the atmosphere for days or weeks are referred to as A)silts. B)muds. C)clays. D)aerosols.

"Making the desert bloom" is a slogan that is used when A)desert areas are irrigated to convert to farmland. B)desert areas undergo flash flooding. C)desert cacti bloom during springtime. D)desert travelers hallucinate an oasis.

Cima dome in the Mojave Desert is a __________ feature. A)barachan dune B)pediment C)dry wash D)playa lake

The height of a dune remains constant when A)the wind speed is constant. B)there is more accumulation on the slip face than the windblown side. C)sand grains blow off the top of the dune as quickly as they are brought up the windward slope. D)the windward slope reaches the angle of repose.

A wind of 48 km/hr can move up to _________ of sand per day. A)10 tons B)5 tons C)0)5 tons D)1 ton

The thickest loess deposits of China exceed A)300 m. B)1000 m. C)500 m. D)725 m.

Wind annually transports ______ tons of material from the Sahara Desert to the Atlantic Ocean. A)25 million B)25 billion C)260 million D)200 million

"Sand seas" that cover up to 500 000 km³ are referred to as A)playas. B)wadis. C)ergs. D)pediments.

Loess is a highly beneficial type of sediment for soils except for one major flaw.What is it? A)Loess soils lacks nutrients. B)Loess tends to develop hardpan soils. C)Loess soils are easily eroded. D)Loess soils are too "sandy."

What are ventifacts? A)sand dunes B)desert pavement C)sand drifts D)wind-faceted pebbles

How much of Earth's land surface is covered by loess? A)5% B)10% C)30% D)50%

Which of the following statements about loess is false? A)It is composed of fine-grained sediments. B)Beds of loess lack internal stratification. C)Major deposits of loess occur in China and North America. D)Loess deposits make poor soils.

Boomerang-shaped sand dunes are termed A)barchans. B)crescents. C)lunar. D)horse shoes.

The closet terrestrial analog for the surface of Mars is that of A)the Gobi Desert. B)the Sahara Desert. C)Death Valley. D)Antarctica.

Desert streams deposit most of their sediments in A)deltas. B)river channels. C)floodplains. D)alluvial fans.

Which of the following grain sizes would a stream easily move that wind could not? A)clay B)silt C)sand D)cobble

In terms of their surface deserts are one-fifth _____________ and fourth-fifth _____________. A)oasis; sand B)sand; rocky or desert pavement C)vegitation; barren D)playa lakes; sand dunes

What phenomenon could help keep solar panels of Martian rovers free of dust? A)strong wind gusts B)martian rain C)solar wind D)dust devils

Which wind belt is located between 30˚N and 60˚N? A)the northerlies B)the westerlies C)the easterlies D)the trade winds

What is the Coriolis effect? A)a type of air circulation B)the effect of Earth's rotation on global air circulation C)local weather effects D)the effect of solar flares on Earth's climate

What causes the Coriolis effect? A)the Sun B)Earth's rotation C)Earth's magnetic field D)the tilt of Earth's axis

What grain feature of quartz is only found in the eolian environment? A)roundness B)tinting C)high luster D)matting

Other than on Earth,where have ventifacts been seen? (Hint: Dust storms are common there.) A)Mercury B)Mars C)Venus D)the Moon

Outside of the regular large desert environments (e.g.,the Sahara and the Gobi),sand dunes are found next to lakes and beaches.Why is that? A)Wet or damp sand grains stick together more easily than dry ones. B)Water waves,tides,or storms pile the sand up,which starts dunes. C)There is ample supply of sand and strong onshore winds. D)Near-shore vegetation help trap the sand,allowing large sand dunes to pile up.

Which of the following statements about sand dunes is false? A)Grains migrate up the dune slope by saltation. B)Dunes migrate downwind. C)Cross-bedding is preserved during dune movement. D)All sand dunes are made of quartz grains.

As a dune grows in height, A)it gets steeper on the leeward side. B)saltation becomes less important in sand movement. C)wind speeds increase at the top. D)it slows down its forward movement.

What ultimately limits the height of a sand dune? A)the amount of sand it contains B)saltation C)wind speed D)air temperature

How high are the tallest sand dunes on Earth? A)10 meters B)25 meters C)100 meters D)250 meters