Introduction to Geology

Introduction to Geology

Quiz 13 - Deserts and Arid Regions

1. Arid regions comprise approximate what percent of Earth's land area?
a. 1
b. 5
c. 10
d. 30
e. 50

2. Why are most middle-latitude deserts located where they are?
a. They coincide with zones of subtropical highs where there are sinking wind patterns.
b. No rivers run through them.
c. They are far removed from oceans.
d. They receive too much sunlight.

3. Mountain ranges that may block precipitation from reaching certain areas, creating:
a. rainshadows.
b. alluvial fans.
c. subtropical highs.
d. playas.

4. Semiarid regions with grassland that often surround deserts are called:
a. tundra.
b. plains.
c. plateaus.
d. steppe.
e. pediment.

5. What is responsible for most erosion in deserts?
a. wind
b. running water from infrequent storms
c. glaciers
d. plants and animals

6. A common desert landscape with typically very rugged relief, a heavily eroded appearance, and bares little or no vegetation is called:
a. an arroyo.
b. ephemeral.
c. badlands.
d. caliche.

7. A gently inclined erosional surface carved into bedrock, typically covered locally with stream gravels, and that has developed at the foot of mountains is called:
a. a pediment.
b. an arroyo.
c. an inselberg.
d. a badlands.

8. Alluvial fans (and bajadas) form along the base of mountain ranges in desert basins. Where would you expect to find the coarsest grained sediments on an alluvial fan?
a. in the upper alluvial fan deposits.
b. in the mid alluvial fan deposits.
c. in the lower alluvial fan deposits.
d. in the toe of alluvial fan deposits along trunk streams or on playas.

9. A thin layer of gravel layer that accumulates on the surface of many desert landscapes where the wind has removed finer materials (sand, silt, dust) is called:
a. alluvial fan deposits.
b. a pediment.
c. desert pavement.
d. caliche.

10. Ancient Lake Manly was:
a. a lake that existed in Death Valley at the end of the last ice age.
b. a lake that once flooded Death Valley to a depth of 800 feet, but had now completely dried up.
c. a large lake that expanded and contracted (the surface rose and fell) many times, leaving a record of many climate changes in the region.
d. all of the above.

11. Which of the following constitutes most of the bed load carried by wind?
a. boulders
b. sand
c. soil
d. fine dust particles
e. pebbles

12. Which type of desert erosion consists of the lifting and removal of loose material?
a. ventifact
b. deflation
c. varnish
d. pavement
e. abrasion

13. Desert land features created by water include all of the following except:
a. alluvial fans.
b. playas.
c. bajadas.
d. dunes.

14. Loess is:
a. found in areas downwind of deserts and glacial outwash plain regions.
b. an extensive blanket of silt.
c. sediment that was carried in suspension by wind.
d. all of the above.

15. The largest arid region in North America is:
a. the Sonoran Desert.
b. the Chihuanhuan Desert.
c. the Colorado Desert.
d. the Mojave Desert.
e. the Colorado Plateau.

Clues where to find answers.