Geology Chapter 13 Quiz
True
Loess is a deposit of wind-blown silt primarily composed of unweathered angular grains of quartz and feldspar.
True
Some of the world's deserts are the result of the rain shadow effect of mountain ranges.
Desert pavement
_______ is a thin surface layer of closely packed pebbles found in deserts.
butte
A ______ is a narrow hill of resistant rock with a flat top and very steep sides found in some deserts.
True
A desert is any region which has a dry or arid climate with a low rainfall of less than 25 cm per year.
longitudinal
A large dune type is the _______ (or seif) dune, which forms a ridge parallel to prevailing wind direction.
False
A transverse dune is a relatively straight, elongated dune oriented parallel to wind direction.
through-flowing streams
Because of their low rainfall, intermittent stream flow, and dry stream beds, desert lack ____.
saltation
Because sand grains are heavier than clay and silt particles, sand grains move close to the ground in a leaping pattern called ______.
True
Dune types are influenced by wind velocity.
beaches
Dunes are not just desert features, they are commonly found near ____.
sand storms
High-speed winds can cause ____, clouds of sand moving rapidly near the land surface.
False
In passing over a dune, wind scours sand from the downwind or slip face.
barchan
Where sand supply is limited a _____ dune usually forms.
parabolic
A ____ dune is deeply convex and its horns point upwind.
True
Most sand dunes are asymmetric in cross section with a gentle slope facing the wind and a steeper slope on the downwind side.
polar
Not all deserts are hot. Descending air near the North and South poles creates ____ deserts.
barchan
The "horns" in a _______ dune point in a downwind direction.
desertification
The expansion of deserts into once populated areas is known as ___.
flash floods
The high runoff following sporadic desert downpours can create sudden local floods called ______.
deflation
The removal of clay, silt, and sand particles from a land surface by wind is called _____.
True
The world's best-known deserts lie in a belt 10-15 degrees centered at latitude of 30 degree (North and South)
True
Thin rocky soil and slow rates of creep make desert topography steep and angular.
wind
This agent of erosion and deposition is most effective on fine sediment that is dry.
playa
When the desert sun dries a lake, a very flat surface underlain by hard mud-cracked clay called a _______ may form.