Geography 3
Areas that are Arid (<250 mm precip) and sparsely vegetated
Deserts
What is the dominant fluvial process in a clear, sediment-poor stream moving down a steep slope?
Downcutting
Stream terraces form as teh result of which of the following processes?
Downcutting following the rise of the landscape produces stream terraces.
Which of the following type of sand dunes could be produced in a sandy desert with winds sometimes blowing from the northeast, sometimes from the west, and sometimes from the southeast?
Star
How do alluvial fans form?
Stream gradients decrease at the mountain front, causing deposition.
Why does a delta form?
Stream velocity slows sufficiently that the load is dropped.
What is suspended load?
The fine-grained particles that travel in the water column above the stream bed
Which of the following is likely to occur to an incised meander after it reaches equilibrium with its new base level?
The incised meander will cause only minor erosion of the canyon walls.
Dune Features
angle of repose, slipface, crest, blackslope, avalanche deposits, accretion deposits
The elevation limit of a stream downcutting on a land mass is called ________.
base level
A stream's ________ is (are) chemically altered and transported.
dissolved load
How does the rate of rock weathering in dry climates compare with the rate in humid regions?
dry climates have much lower rates of chemical weathering and mechanical weathering than humid climates
The land separating adjoining valleys is known as a(n) ________.
interfluve
Which of the following type of sand dunes occurs as very long, parallel ridges of sand with the narrow width aligned along the prevailing wind direction and which are also called seif dunes?
longitudinal
What type of sand dune resembles a sea of sand with "waves" oriented perpendicular to the wind direction?
transverse
Dune Types
transverse, barchan, sief, star
What is the most important erosional agent in deserts?
water
How is loess related to glaciers
when glaciers retreat, their meltwater contains loess, which can be picked up by winds and distributed elsewhere
What is a floodplain?
A flat surface next to a river channel
What is a meander scar?
A landscape feature formed after an oxbow lake dries up.
What is an oxbow lake?
A meander that has been cut off from the original stream channel
When the local gradient of a stream changes as it goes from a mountainous area to a large flat-lying area, which of the following features could form?
An alluvial fan
How does differential erosion impact arid landscapes?
Arid slopes are less rounded; resistant rocks make escarpments and nonresistant rocks form gentler slopes.
What type of sand dune is shaped like a croissant and has horns that point in the direction towards which the wind blows?
Barchan
What are the three types of loads carried by streams?
Bed load, suspended load, dissolved load
What are the two mechanisms of wind erosion?
Deflation and abrasion
Where do deposition and erosion of material occur along a meander?
Deposition occurs on the inside of the meander, whereas erosion occurs on the outside.
Which of the following features would you expect to find on the outside bank of a stream meander loop?
A cut bank
Complete this analogy: Bouncing is to sand as suspension is to ___.
Clay
________ is a measure of the particle size a stream can transport.
Competence
Depositional Landforms
Erg, Sandplain, Dune, Playa Lake, salt flat
How does the formation of a natural levee impact flooding?
Natural levees raise the height of the stream channel, reducing the amount of flooding that will occur on the floodplain.
Complete this analogy: Sliding is to gravel as dissolution is to ___.
Ions
What type of stream is associated with the formation of an oxbow lake?
Meandering stream
Which of the following statements accurately describe the erosional processes of meanders that are incising and meanders that are in equilibrium?
Meanders in equilibrium erode primarily in a side-to-side manner and Incising meanders erode primarily by downcutting.
How are oxbow lakes formed?
Oxbow lakes form when one meander erodes into another, cutting off water to part of the stream channel
What is the debris-covered bedrock surface at the base of an eroding desert fault-block mountain?
Pediment
How can pieces of rock in contact with a stream bed move?
Rolling, sliding, bouncing
The process in which small particles are moved along by streamflow or wind in a series of jumps or bounces is ________.
Saltation
What term describes the transport of rock particles, leaves, and litter across the surface in a bouncing motion?
Saltation
Which of the following are part of the bed load?
Sand & Gravel
________ transport(s) materials directly after they are loosened by splash erosion.
Sheet erosion
How is a stream impacted when it suddenly has more load than it can carry?
The stream develops a braided channel.
While working in the field, you come upon a stream that flows in a very deep V-shaped valley. Regarding the history of this stream, which of the following statements is most likely true?
The stream is relatively young.
Which processes result in the widening of the floodplain of a meandering stream?
Undercutting and lateral erosion
What causes meandering streams to downcut and become incised meanders?
Uplift of the land the stream is flowing on
What is a playa commonly occupied by?
an ephemeral lake
What is an ephemeral stream?
an intermittent stream that carries water only in response to specific episodes of rainfall
Which of the following accurately describes the Basin and Range region of the western United States?
a region with alternating mountains and basins that have been produced by normal faulting
A(n) _______ is a cone-shaped deposit of sediment that is deposited when a stream exits the mouth of a canyon.
alluvial fan
Flow in a stream usually is fastest ________.
near the center and slightly below the surface
On a meandering stream, maximum erosion takes place along the ________.
outer edge of the meanders
Fluvial process includes both the stream flow within valleys as well as ________.
overland flow
. Which of the following type of sand dunes contains two horns that point in the direction from which the wind is blowing?
parabolic
Mesa and scarp assemblage
plateau, mesa, butte, pinnacle, pedestal, pillar
An oxbow lake was formerly a ________.
river meander
How do pieces of rock move under the influence of wind?
rolling, sliding, bouncing, suspension
desert weathering
rounding, frosting salt wedging, desert vanish
