Chapter 8: Mass Movements, Wind, and Glaciers

Question 1

What is a mass movement

Answer 1

the downslope movement of loose sediments and weathered rock resulting from the force of gravity

Question 2

What variable influence the frequency of mass movements

Answer 2

1. The material’s weight resulting from gravity
   - works to pull the material down a slop
2. Materials resistance to sliding or flowing
3. Triggers
   - earthquakes etc. that work to pull material down a slope
4. Water
   - too little water, prevents sediment grains from holding together, increasing potential for movement
   - addition of water pulls the grains together and makes them more stable
   - too much water can make the the slope unstable because it increases the weight and acts as a lubricant

Question 3

What is a creep

Answer 3

the slow, steady, downhill flow of loose, weathered Earth materials, especially soils
loose materials on almost all slopes undergo creeps

Question 4

What is a flow

Answer 4

Earth materials flow as if they were a thick liquid, the materials can move slowly as a few sm/year or rapidly as km/hour.
common in sloped semi-arid regions that experience intense, short lived rainstorms

Question 5

Mudflow vs Earth Flow

Answer 5

Earth flows are moderately slow movements of soild, where as mudflows are swiftly moving mixtures of mud and water (triggered by earthquakes, common around volcanoes)

Question 6

What are slides

Answer 6

A rapid downslope movement of Earth materials that occurs when a relatively thin block of loose soil, rock, and debris separates from the underlying bedrock
occurs commonly along steep slopes where the soil is fully saturated

Question 7

What are slumps

Answer 7

When the mass of material in a landslide rotates and slides along a curved surface, a slump is produced
occurs along highways or where slopes of soils are extremely steep

Question 8

What is an avalanche

Answer 8

Landslides that occur in mountainous areas with thick accumulations of snow

Question 9

What are rock falls

Answer 9

On high cliffs, rocks are loosened by physical weathering processes, such as freezing and thawing and by plant growth. As rocks break up and fall directly downward, they may bounce and roll ultimately producing a cone-shaped piled of rocks called a talus

Question 10

What is abrasion

Answer 10

When particles of sand sub against the surface of rocks or other materials. Occurs as part of the erosional activities of winds, streams, and glaciers.

Question 11

Barchan Dunes

Answer 11

The most common type of dunes. Generally form in areas of constant wind direction

Question 12

Transverse Dunes

Answer 12

Form in areas with strong winds and abundant sand

Question 13

Parabolic Dunes

Answer 13

Form in areas with moderate winds and some vegetation. Common on seacoasts.

Question 14

Longitudinal Dunes

Answer 14

Form in area with high, somewhat variable winds and little sand

Question 15

What are ventifacts

Answer 15

Rocks shaped by wind blown sediments.

Question 16

What is loess

Answer 16

Thick, wind-blown silt deposits. Occur where precipitation is adequate, loess soils are some of the most fertile soils on Earth because hey contain abundant minerals and nutrients

Question 17

What is a glacier

Answer 17

A large moving mass of ice

Question 18

How do glaciers form

Answer 18

Cold temperatures keep fallen snow from completely melting, and each year, the snow that has not melted accumulates in an area called a snowfield. Thus the totals thickness of the snow layers increases as the years pass and a glacier begins to form. The weight of the top layers of snow eventually exerts enough downward pressure to force the snow below to crystallize into ice.

Question 19

Valley glaciers

Answer 19

Glaciers that form in high, mountainous areas

Question 20

Continental glaciers

Answer 20

Glaciers that cover a broad, continent-sized areas.

Question 21

How do glaciers effect the landscape

Answer 21

When a valley glacier moves, it breaks off pieces of rock and fallen rocks accumulate around the edges. They act like grains of sand on sandpaper and scratch out paralelll lines on the bedrock. Glaciers can carve out U-shaped valleys as well as deep depressions (cirques).

Question 22

esker

Answer 22

long winding ridges of layered sediments that are deposited by streams flowing under a melting glacier

Question 23

drumlin

Answer 23

glaciers that move older moraines form the material into an elongated landforms called drumlins

Question 24

moraine

Answer 24

ridges consisting of till deposited by glaciers

Question 25

arête

Answer 25

a narrow ridge of rock which separates two valleys. where two cirques on opposite sides of a valley meet, they form a steep ridge called an arête

Question 26

cirque

Answer 26

deep depressions carved out by glaciers

Question 27

Horn

Answer 27

Where there are glaciers on three or more sides of a mountaintop, a steep pyramid shaped peak forms. This is a horn

Question 28

How do valley glaciers move

Answer 28

Valley glacier occurs when the growing ice mass becomes too heavy to maintain its rigid shape and begins to flow much like a liquid. As a valley glacier moves, deep cracks in the surface of the ice, called crevasses, can form. The speed at which it flows is affected by the slope of the valley floor, the temperature, and thickness of the ice, and the shape of the valley walls. The sides and bottom of a valley glacier move more slowly than the middle because the friction slows down the sides and bottom.