Geology - Test 3

A __________ is a common result of creep.

broken retaining wall

Where does the clay that accumulates in the B horizon come from?

A and E Horizons

What physical feature serves as the drainage divide on the western side of the Amazon River drainage basin?

Andes

What is the soil order in areas of North America that is most commonly associated with the deserts and xeric shrublands biome?

Aridisols

Just as soils are the foundation for vegetation, vegetation can also influence the characteristics of soils. Which of the following biomes in North America is most often associated with Spodosols?

Boreal forests/taiga

Think about the soil horizons that make up the solum. Why isn't the C horizon part of the solum?

The C horizon contains unweathered parent material.

Define mass wasting.

The downslope movement of sediment and rock under the direct influence of gravity

Which of the following statements is true regarding the aftermath of the Gros Ventre rockslide?

The rockslide debris dammed up the river and formed a lake.

When dry sediment accumulates, the angle of repose represents what property of the deposit?

The steepest angle at which those sediments can accumulate and remain stable.

What is the dominant soil order in areas of North America with average annual precipitation ranging from 60 to 79 inches?

Ultisols

Which of the following would decrease soil erosion? CHOOSE ALL THAT APPLY.

Vegetation planted parallel to the slope Adding terraces to a slope

How can the addition of water make a slope fail, creating a landslide?

Water in pore spaces reduces cohesion between particles. Water will mix with the sediments to create a mudslide. Water makes the slope material heavier.Water can easily flow downslope.

Which of the following responses are examples of how water can promote mass wasting?

When water is added to weathered particles, the mass of the sediment is increased, which can cause slope instability. Water can saturate sediment, reducing the integrity of the slope and allowing it to move. Waves and streams can undercut banks and cliffs, causing them to fail.

In North America, which agricultural region (anthropogenic biome) is most closely associated with areas of stable terrain?

Wildlands

A __________ acted as a sliding surface across which material moved downhill during the Gros Ventre Slide.

clay layer

are very gradual mass movements in which the whole slope moves downhill slowly.

creeps

Which of the following features would you expect to find on the outside bank of a stream meander loop?

cut bank

Besides flood control, a(n) can also be used to generate hydroelectric power. However, they are expensive to build and maintain.

dam

in water velocity causes sediment to be deposited on the fan.

decrease

Which landscape is most prone to generating landslides?

mountains

Permafrost is __________.

permanently frozen ground of tundra and subarctic climates that has remained 0°C for two years or more

Heavy rainfall caused the clay to lubricate and the sandstone to become __________.

saturated and heavy

What rock type is the easiest for a river to cut through?

shale

A mass movement in which a cohesive block of earth or rock slips downhill relatively quickly in one piece along a zone of weakness is called a

slide

A __________ is formed when vertical incision by a stream is the primary process, with relatively minimal mass wasting.

slot canyon

Mass movements that move blocks of materials and unconsolidated materials down a curved surface creating scarps on a slope are known as

slump

What is used to keep the Trans-Alaska pipeline from melting permafrost?

stilts

Alluvial fans occur where a _____ exits the _____ and enters the _____.

stream; mountains; basin

What is suspended load?

the fine-grained particles that travel in the water column above the stream bed

Imagine a valley containing four stream terraces. Where would the youngest stream terrace be found?

the lowest

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

Of the following, which is not an example of Earth's external processes and/or external process-driven phenomena?

volcanoes

All modification of Earth's outer surface is initiated by which of the following processes?

weathering

When do streams erode laterally?

when downcutting is occurring in easy-to-erode sediment or rock

When do stream terraces form?

when streams exist under alternating erosional and depositional conditions

What is a floodplain?

a flat surface next to a river channel

Which of the following is a reason the Gros Ventre rockslide took place?

Because the river eroded material at the valley base, there was no support of the material upslope.

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.

The Congo River Basin, located primarily in the Democratic Republic of the Congo, is associated with which two natural regions?

Evergreen forest and savanna

How is a fall different from creep?

Falls occur rapidly and in areas with high slope, whereas creep occurs slowly in areas with low slope.

Which of the following landslides was caused in part because the underlying sedimentary bedrock was oriented parallel to the slope that failed?

Gros Ventre Landslide (Wyoming)

Which of the following statements accurately describe the erosional processes of meanders that are incising and meanders that are in equilibrium?

Incising meanders erode primarily by downcutting.Meanders in equilibrium erode primarily in a side-to-side manner.

What is an oxbow lake?

Oxbow lakes form when one meander erodes into another, cutting off water to part of the stream channel.

What agricultural practice dominates areas characterized by Oxisols?

Shifting cultivation

How are slumps and slides related?

Slumps are a type of slide in the special case where the rupture surface is curved.

__________ is an example of mass wasting commonly seen in the active layer above permafrost.

Solifluction

is/ are cheap to implement, but it/they can adversely affect property values.

Zoning regulation

What is a meander scar?

a landscape feature formed after an oxbow lake dries up

What is a stream terrace?

a remnant of an older floodplain that sits above the stream valley

What is a natural levee?

a ridge of flood deposits next to a river channel

The Gros Ventre slide is evident today by __________.

a scar, runout area, and landslide debris filling the valley

portion of the fan is outlined in blue.

active

What is name of the near-surface layer that thaws in the summer?

active layer

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

A(n) confines water flow and can experience significant erosion. Constant maintenance is required

artificial levee

The area outlined in orange is a(n) __________, which is an apron of sediment formed by neighboring __________.

bajada; alluvial fans

What are the three types of loads carried by streams?

bed load, suspended load, dissolved load

Over time, mass wasting causes __________.

canyons to widen

Removing obstructions from a river channel is a form of a(n) . It can make a river more navigable, but may also increase bank erosion due to increased water flow.

channelization

The cross-fan profile is concave

down

What is the dominant fluvial process in a clear, sediment-poor stream moving down a steep slope?

downcutting

Which of the following triggers generated the 1958 landslide and tsunami at Lituya Bay, Alaska?

earthquake

When large rocks become dislodged and drop down a steep slope, the mass movement is called a

fall

Which of the following are classifications describing how rock and other material move downslope?

fall, slide, slump, creep, flow

When unconsolidated material moves downslope as a viscous fluid it is called a

flow

When considering mass wasting, which of the following factors is most influential in the downslope movement of weathered particles?

gravity

Which of the following is the major contributing factor in all landslides?

gravity

portion of the fan is outlined in yellow.

inactive

Creep is __________.

mass wasting by the gradual downhill movement of sediment, influenced by freeze-thaw or wet-dry cycles