Deserts Test Bank

Traditionally, a region is defined as a desert if it receives less than ________ centimeters of rain per year.

25

From a climatological perspective, a region is a desert if ________.

yearly precipitation is less than evaporation

A true desert is defined by a lack of what substance?

Water

Most dry lands exist between ________ degrees latitude on either side of the equator.

20 and 30

Which of the following statements about deserts is true?

Although rainfalls are infrequent, erosion and deposition related to water are more important than wind in deserts.

Which of the following areas is known for its rainshadow deserts?

South America east of the Andes

Within water-deficient regions, two climatic types are recognized. What are they?

desert and steppe

Deserts form in the subtropical regions as a result of ________.

subsiding air masses

What is the definition of an ephemeral stream?

An intermittent stream that only has water after specific episodes of rain

There are many names for ephemeral desert streams that remain empty for most of the year. Which of the following is not another name for an ephemeral desert stream?

Playa

________ weathering is most common in a desert environment.

Mechanical

Which of the following can contain large quantities of evaporite minerals such as borate and halite?

Playa

Which desert location in the United States consists of alternating mountain ranges and flatbottomed valleys as a result of fault-block mountains?

Basin and Range Province

Why doesn't interior drainage, such as the drainage that develops in deserts, flow out of the desert?

The water evaporates before the stream can exit the desert region

How was the Salt Pan at Death Valley created? What is the name of such a desert feature?

evaporation; playa

A steep-sided, flat-topped desert hill is known as a(n) ________. 

mesa

________ refers to the bouncing motion sands will display when transported by moving water or wind.

saltation

Which size(s) of sediment commonly make up most of wind's suspended load?

silt

Which set of characteristics would best fit a geologically recent fault-block mountain uplift?

Flat upland surface, steep slopes, and small alluvial fans

Which mechanical weathering process is most common in an arid environment?

salt wedging

What makes up the bulk of the wind-transported suspended load?

silt

What process creates desert blowouts?

deflation by wind

There is no one maximum depth for desert blowouts. They vary in depth depending on conditions present at the location. What controls the depth of all blowouts? 

Amount of water available for dissolution of underlying materials

A(n) ________ is a smooth, polished rock that has been abraded by the wind.

ventifact

What is a yardang?

A wind-sculpted landform oriented parallel to the prevailing wind, often narrow at the base

The ________ was a period of drought in the 1930s in the United States that resulted in significant dust storms blowing fine sediment for hundreds of miles.

dust bowl

________ are mounds and ridges of sand that are deposited by the wind.

dunes

Deposits of silt carried by blowing winds are referred to as ________.

loess

The central United States is covered with extensive deposits of loess. Where did this loess come from?

Rock flour from the braid plains of Pleistocene glacial streams and rivers

Long ridges of sand that form more or less parallel to the prevailing wind where sand supplies are moderate are called ________ dunes.

longitudinal