Deck 6: Sedimentary Rocks

Question 1

How do freezing, thawing, wetting, and drying contribute to soil creep?

A) Gravity exerts a much stronger force when the soil is wet and thawed.
B) The soil becomes much weaker when dry and frozen.
C) The soil expands and contracts, lifting particles then lowering them a slight distance downslope.
D) Eventually these cause the soil and regolith to suddenly slide down the slope.

Answer 1

C

Question 2

Rockslides tend to be more common .

A) as soon as hot weather comes and rock surfaces dry out so they can slip freely
B) in the winter because ice is so slippery and prone to pressure induced melting
C) where rock layers are horizontal or gently inclined and more easily made to slip
D) during the spring thaw when heavy rains and melting snow are prevalent

Answer 2

D

Question 3

What is the physical mechanism that drives creep?

A) freeze/thaw or wet/dry cycles
B) overbearing slopes
C) gravity fluctuations during earthquakes
D) erosion and sedimentation

Answer 3

A

Question 4

Which statement best describes liquefaction?

A) Deep- sea sediments lose water during subduction which liquefies overlying mantle rock.
B) High volumes of liquid are injected into the ground, eliminating its cohesion.
C) Upon intense shaking, surface materials lose their strength and behave as fluid- like masses that flow.
D) Coal beds are heated and liquified for fuel.

Question 5

Which one of the following materials has the maximum, sustainable, slope angle, as determined by the angle of repose?

A) unfractured granite
B) unsorted, crushed rock used for highway paving
C) moist, sandy soil with a clay- rich matrix
D) dry sand

Question 6

All of the following are factors affecting mass wasting except for .

A) water
B) geologic age
C) gravity
D) slope angle

Question 7

Frost wedging and thawing on vertical cliffs produces .

A) alluvial fans
B) fast moving rock glaciers
C) debris flows and torrents
D) talus cones

Question 8

During wet weather or times when snow is melting, what sometimes happens to the downhill toe of a slump?

A) It turns into a rock avalanche.
B) It collapses and is deposited as talus at the base of the slope.
C) It stops moving because water makes the clay sticky.
D) It becomes an earthflow.

Question 9

When and where is solifluction common?

A) rainy season in the tropics
B) monsoon season in India
C) summer in polar regions
D) dry season in grasslands south of the Sahara Desert

Question 10

Which natural factors routinely weaken slope materials and make them more prone to mass wasting and failure?

A) ablation, chemical weathering, and terracing of slopes
B) temperature changes and tidal variations in gravitational acceleration
C) devegetation, oversteepening, saturation, and vibrations
D) erosion, sedimentation, and lithification

Question 11

Solifluction occurs wherever sit upon that will not allow excess water to drain away to deeper levels.

A) glaciers, frozen soils
B) water- saturated soils, dense clay hardpan or impermeable bedrock or permafrost
C) loose soil, volcanic ash
D) talus cones, well jointed bedrock

Question 12

A occurs where slopes are water saturated above permafrost.

A) rock fall
B) debris flow
C) slump
D) solifluction lobe

Question 13

Which of the following travels on compressed air and are usually triggered by earthquakes?

A) rockslide
B) slump
C) rockfall
D) solifluction lobe

Question 14

Which mass wasting process has the fastest rate of movement?

A) earthflow
B) rockslide
C) solifluction
D) slump

Question 15

describes the downslope movement of cohesive material along a well defined surface such as a joint or a bedding plane.

A) Fall
B) Avalanche
C) Slide
D) Woo hoo!

Question 16

How do mass wasting processes differ from erosional ones?

A) Mass wasting is always very fast and catastrophic whereas erosion is always slow and gradual.
B) Mass wasting does not require a transport agent such as wind, water, or glacial ice.
C) Mass wasting is a spring and summer phenomenon while erosion is year around.
D) Erosion usually requires steep slopes whereas mass wasting can happen even on flat terrains.

Question 17

The largest slumps and debris flows occur along the .

A) shorelines of Hudson Bay
B) oversteepened mountain slopes in recently deglaciated valleys
C) caldera rims of major composite cone volcanoes
D) continental shelf edge and continental slopes

Question 18

Consider a steep highway cut made by removing slightly weathered to fresh, fractured, granite bedrock. Which of the following situations is most stable against rockslides?

A) three sets of closely spaced angular fractures
B) one set of widely spaced, sub- horizontal fractures
C) two sets of fractures, one widely spaced and sub- horizontal, the other inclined towards the highway
D) two sets of fractures, one inclined toward the road and the other into the slope

Question 19

Which rockslide killed 20 campers when debris dammed a river and buried the campground?

A) Montana 1959
B) Quebec 2010
C) Alberta 1903
D) Missouri 1811

Question 20

What two geologic factors prepared Turtle Mountain or made it prone to slides like that of April 29, 1903?

A) heavy rain and snowpack melt, causing debris flows
B) oversteepening of the mountain by glacial erosion and well- developed joints in the rocks
C) Blackfoot hex on the mountain, and excessive game trails
D) active volcanism and an earthquake

Question 21

What is the chief mass wasting concern associated with permafrost?

A) Manmade structures tip, sag, and slide when the permafrost melts because of insulation or heating associated with the structures.
B) Frozen soils fail and slide like fractured bedrock.
C) Debris flows of ice and soils occur frequently.
D) Ice in the frozen soils is low density and low strength, failing by fracture under any applied load.

Question 22

Slumps characteristically have and move downslope in a series of .

A) flat planar sheets, in discreet slip events, earthquake induced movements
B) headwall scarp, coherent mass, rotational blocks
C) steep talus cones, in sudden jumps, inclined planes
D) overlapping lobes, by very slow creep, annual to decadal events

Question 23

How do forest or wild fires contribute to mass wasting?

A) via wind transport of fines during the fire
B) by unloading the slope and reducing the rate of mass wasting
C) Human disturbance caused by fire fighting activities is the most destructive and leads to further slope failures.
D) by removing stabilizing vegetation

Question 24

How does human activity not induce thawing of permafrost in the Arctic?

A) travelling on and removing tundra vegetation
B) building roads and railways
C) flying over permafrost areas
D) constructing buildings directly on the ground

Question 25

What are the most serious mass wasting hazards in mountain valleys?

A) rock bursts
B) airborne rockslides
C) glacier bursts
D) debris flows

Question 26

What two properties of rain water and snow melt have the greatest effect on soil strength and slope stability?

A) solvation properties and surface tension
B) electric conductivity and viscosity
C) acidity and strong dipole forces
D) increased lubrication and added weight

Question 27

When descending cohesive material moves "en masse" along a curved surface of rupture that just formed, it is termed a .

A) flow
B) slump
C) sag
D) creep

Question 28

How are talus slopes built?

A) by rock falls
B) by debris flows
C) between major earthquakes by intense low temperature chemical weathering
D) by glacial transport

Question 29

Slumps are a common form of mass wasting particularly in .

A) cohesive water saturated unconsolidated soils and clayey sediments
B) fluidized debris in steep canyons
C) granular sands and gravels
D) angular rocky rubble on steep bedrock slopes

Question 30

Excavated road cuts or quarry faces, and eroding natural river bluffs and sea cliffs, are all examples of which can lead to mass wasting.

A) oversteepening
B) lithospheric hydration
C) landscape stabilization
D) vivisection

Question 31

What term denotes the exposed slip (fracture) surface beneath a slump block?

A) toe
B) scarp
C) sole
D) scoop

Question 32

All of the following are possible indicators that creep is occurring except for .

A) tilted fences or power line poles
B) cracks in roads or sidewalks
C) a thick soil profile
D) curved tree trunks

Question 33

Which mass- wasting event involves movement on a zone of compressed air?

A) earthflow
B) rockslide
C) creep
D) slump

Question 34

Which of the following statements concerning debris flows is not true?

A) Debris flows deposit talus slopes.
B) In hilly areas, debris flows move down the canyons and stream valleys.
C) Debris flows may be caused by heavy rains or melting snow.
D) Debris flows can move and carry very large boulders and other coarse debris.

Question 35

Which statement best describes slumping, a mass wasting process?

A) A mass of soil or regolith becomes saturated with water and suddenly flows downhill to the base of the slope.
B) The soil and regolith move downhill very slowly.
C) A block or blocks of unconsolidated regolith slide downhill along a curved slip surface.
D) Blocks of hard bedrock rapidly slide downhill along fracture surfaces.

Question 36

Which of the following mass movements is most likely to occur in a geologic setting where the rock strata are inclined?

A) creep
B) slump
C) rockslide
D) debris flow

Question 37

Consider a weathered rock or soil particle lying on a slope. How will the gravitational force pulling the particle downward along the land surface vary with the inclination of the slope?

A) It will decrease as the slope angle is decreased.
B) It will increase as the slope angle is decreased.
C) It is not affected by the slope angle.
D) It will decrease as the slope angle is increased.

Question 38

A geologist wants to locate a horizontal coal bed on a soil- covered slope where soil creep is active. A distinctive sandstone bed underlies the coal bed. On the basis of weathered sandstone fragments in the soil, where is the coal bed?

A) just below the lowest piece of sandstone seen in the soil
B) just below the highest piece of sandstone seen in the soil
C) just above the highest piece of sandstone seen in the soil
D) just above the lowest piece of sandstone seen in the soil

Question 39

Why was the Alaskan pipeline built above ground and insulated?

A) to protect the pipeline from damage by caribou migration
B) to protect the pipeline from damage by volcanism
C) to protect the pipeline from damage due to thawing ground and to keep the oil fluid
D) to protect against damage from roots of large trees uprooted in windstorms

Question 40

Which one of the following operates primarily in areas of permafrost?

A) solifluction
B) slump
C) debris flow
D) rockslide

Question 41

The angle of repose in unconsolidated materials varies from depending on the size and cohesion of particles.

A) 5° to 14°
B) 25° to 40°
C) 50° to 90°
D) 2.5° to 4.0°

Question 42

What do slumps, rockslides, debris flows and earthflows all have in common?

A) They are all forms of mass wasting.
B) They all transport on a cushion of compressed air.
C) They all happen in frozen soils on steep slopes.
D) They all require water for lubrication.

Question 43

What is the major and immediate controlling force in mass wasting?

A) Chemical weathering as bonds fall apart, weakening minerals.
B) Gravity, as this pulls matter downhill.
C) Convection, as this drives mantle convection and tectonic uplift.
D) Coriolis force, as it controls cyclonic winds and transport of precipitation.

Question 44

Which mass wasting process has the slowest rate of movement?

A) rockslide
B) earthflow
C) creep
D) slump

Question 45

Which of the following contains ice wedges?

A) felsenmeer
B) thermokarst
C) patterned ground
D) pingo

Question 46

_ of soil and regolith commonly flow gradually downhill in humid areas following heavy rain.

A) Earthflows
B) Turbidity currents
C) Lahars
D) Glowing avalanches

Question 47

How do the strength and cohesion of clay- rich regolith or soil change with the addition of water?

A) Water reduces the strength of clays but raises the cohesion of the soil.
B) Water lowers the strength and cohesion.
C) Water does not affect the cohesion but lowers the strength.
D) Water increases the strength and cohesion.

Question 48

What will the long term effect of mass wasting be on oversteepened slopes?

A) It will fill in the lowland up to the level of the surrounding highland region.
B) It will perpetuate catastrophic mass failures until the entire highland region is removed
C) It will eventually restore an equilibrium profile by reducing the slope angle.
D) It will cause the steep slopes to retreat uniformly, widening the valley but keeping the steep slopes at the margins.

Question 49

Which of the following remedies are not used to stabilize rock faces along the Sea- to- Sky highway?

A) sprayed cement
B) fluid injection
C) rock bolts
D) metal screens (mesh)

Question 50

What removes vegetation from a slope?

Question 51

How does water affect the internal cohesion of clay- bearing soils and regolith?

A) The soil or regolith has no internal cohesion when wet or dry.
B) The soil or regolith has equal internal cohesion when wet or dry.
C) The soil or regolith has less internal cohesion when wet than when dry.
D) The soil or regolith has more internal cohesion when wet than when dry.