Geology: Ch. 19 (Deserts and Winds)

Which one of the following is determined by the angle of repose for dry sand?

inclination angle of a dune slip face

In which area would surface water most effectively infiltrate into the local groundwater system?

streams flowing in the numerous channels of an alluvial fan

Which one of the following is a low-latitude desert characterized by high atmospheric pressures and descending air masses (not rain shadow deserts).

Sahara Desert; northern Africa

Most dry lands lie between ________ degrees north and south of the equator.

20 and 30

During a typical sandstorm, saltating sand grains reach a maximum height of ________ above the land surface.

 2 meters

Which one of the following is the one best measure of the wetness or dryness of a region?

difference between annual precipitation and evaporation potential

Rainshadow deserts are common in ________.

vast, dry, steppe lands like the Great Plains

________ have rainfall amounts and soil moisture contents between those of true deserts and humid lands.

Steppes

Desert and steppe lands cover about what percentage of Earth's land area?

30%

Deposition of glacial rock flour from blowing winds is responsible for ________.

loess deposits

How are sand grains transported by the wind?

by saltation in the first few meters above the land surface

A ________ is an intermittent stream channel in the dry land areas of the western United States.

wash

________ refers to the "bouncing" mode of sand transport in a windstorm or stream.

Saltation

A ________ is formed by abrasion of rocks by windblown sand.

ventifact

Which one of the following statements concerning rock weathering is true?

Warm temperatures and high soil moisture contents accelerate chemical weathering.

Inselbergs are ________.

bedrock hills in a highly eroded desert landscape

________ dunes are long, high, sand dunes parallel with the prevailing wind direction.

Longitudinal

How is desert pavement formed?

Runoff and deflation carry off the silt and clay, leaving coarser particles behind.

A ________ is a crescent-shaped dune whose tips point downwind.

barchan

________ dunes result from persistent, onshore winds in certain coastal areas.

Parabolic