Deck 47: Wind As a Geomorphic Agent

Question 1

Wind velocities are _____ near the ground surface.

A) highest
B) almost zero mpg
C) fluctuate from near zero to greater than 100 mph
D) about 10 mph

Answer 1

B

Question 2

Wind erosion increases when:

A) the rate of velocity increases slowly above the ground surface
B) the rate of velocity stays constantly low above the ground surface
C) the rate of velocity increase reaches 10 mph above the ground surface
D) the rate of velocity increases rapidly above the ground surface

Answer 2

D

Question 3

Which factor of wind is the most important in erosion?

A) wind speed
B) wind direction
C) both a and b
D) neither wind speed or direction of wind affects erosion

Answer 3

A

Question 4

Surface roughness such as that associated with vegetation will:

A) increase wind erosion
B) decrease wind erosion
C) first decrease and then increase wind erosion
D) none of these, surface roughness does not impact wind erosion

Question 5

Grains are moved by wind through which process?

A) saltation
B) suspension
C) surface creep
D) all of these

Question 6

By which process are silt- and clay-sized grains moved within a stream system?

A) saltation
B) suspension
C) surface creep
D) none of these

Question 7

The following is not an erosional landform produced by winds.

A) dune
B) deflation hollows
C) desert pavement
D) yardang

Question 8

_____ is an erosional landform where there is a concentration of packed pebbles.

A) dune
B) deflation hollows
C) desert pavement
D) yardangs

Question 9

Generally, the steepest portion of the dune is the:

A) windward slope
B) slipface
C) crest
D) trough

Question 10

The direction in which migrating dunes are moving can be determined by observing the cross-bedding of a dune, formed by the movement of sand up the lower-angle windward slope and deposition along the steeper slip face side.

Question 11

Dunes covered by very little vegetation probably indicates that the dune is:

A) unstable and active
B) stable
C) non-active
D) transitioning from unstable to stable

Question 12

Barchans form in areas with strong unidirectional winds and a large sand supply.

Question 13

The points or horns of a parabolic dune point _____.

A) upwind
B) downwind
C) in a direction perpendicular to wind
D) all of these

Question 14

Longitudinal dunes form in areas with one prevailing wind direction.

Question 15

In a sandstorm, ___ is the dominant mode of particle movement.

A) saltation
B) suspension
C) siltation
D) laminar flow

Question 16

Yardangs are formed when wind:

A) removes all fine particles and exposes the flat bedrock
B) deposits sand in the form of a ridge
C) leaves a pavement of flat pebbles on the ground surface
D) cuts troughs into soft bedrock leaving a ridge of that rock

Question 17

During deflation, what types of particles are carried away most easily?

A) Angular sand grains
B) coarsest-grained sand
C) finest-grained sand
D) rounded sand grains