Deck 15: Weathering, Soil, and Unstable Slopes

Question 1

What happens when rocks oxidize near Earth's surface?

A) minerals in the rock release oxygen that can break down adjacent rocks
B) oxygen combines with water to create weak acids that weather rocks
C) minerals, especially those with iron, combine with oxygen
D) oxygen combines with silica to make quartz

Answer 1

C

Question 2

Which of the following factors control how minerals weather?

A) the strength of the bonds in minerals
B) what type of mineral is present
C) the temperature at which the original minerals formed
D) whether a mineral typically crystallizes early or late in Bowen's Reaction Series
E) all of these

Answer 2

E

Question 3

What concepts can be explained using this diagram?

A) the movement of water between the oceans and the land
B) how precipitation ends up in rivers or groundwater
C) how weathering causes the seas to become saltier
D) all of these

Answer 3

D

Question 4

The layer of quartzite in this photograph would mostly weather by:

A) dissolution
B) hydrolysis
C) physical weathering
D) spontaneous combustion

Question 5

Some rocks and minerals are not stable at the surface because they:

A) are exposed to water
B) formed in high-temperature environments
C) formed in high-pressure environments
D) are exposed to oxygen
E) all of these

Question 6

Where does the quartz in granite typically end up?

A) as small clay minerals that are deposited in lakes and the sea
B) quartz does not weather and so it keeps the granite from weathering
C) it ends up as sand in rivers, dunes, and beaches
D) it is converted into feldspar and weathers into clays

Question 7

What happens to the surface area of exposed rock if a rock is fractured?

A) there are more pieces, but the surface area does not change
B) the surface area does not change because the volume does not change
C) the surface area increases as the rock is fractured
D) the surface area decreases as the rock is fractured

Question 8

What is the dominant type of weathering is shown in this photograph?

A) dissolution
B) chemical weathering
C) debris flow
D) hydrolysis
E) physical weathering

Question 9

Which of the following is true about how weathering affects fractured rocks?

A) weathering affects rocks from the outside in, forming an outer weathered zone or rind
B) weathering attacks corners from three sides and so these are preferentially removed
C) preferential weathering along fractures can cause blocks to become rounded
D) all of these

Question 10

What is the main type of weathering illustrated by this weathered limestone?

A) physical weathering
B) dissolution
C) oxidation
D) exfoliation

Question 11

Joints in the landscape:

A) mostly form at depth and are uplifted to the surface
B) can detach thin slices of rock parallel to the land surface
C) cause highly jointed areas to be less resistant to weathering than more jointed ones
D) all of these

Question 12

Which of the following does NOT physically loosen rocks on the surface?

A) water contracting as it freezes
B) crystals of salt and other minerals that exert an outward force on fractures
C) roots that pry apart fractures as the root grows in size
D) joints that form when rock pressures are released
E) rodents and other burrowing organisms

Question 13

What events caused so much damage along the north coast of Venezuela in 1999?

A) a landslide shook loose a large piece of the mountains that caused the water in the reservoir to flood local towns
B) torrential rains caused debris flows and flash floods that raced through cities
C) the slow movement of slopes downhill broke apart houses but did not kill any people
D) overgrazing caused a loss of grass cover and resulted in severe soil erosion

Question 14

What should have warned the people of coastal Venezuela that they were in a hazardous zone?

A) the cities were built upon alluvial fans
B) the houses had been built on debris flow deposits
C) the areas above the city had steep unstable slopes
D) all of these

Question 15

What is a common rock that can be dissolved by water and weak acids?

A) quartzite
B) quartz-rich sandstone
C) limestone
D) all of these

Question 16

Which of the following are true about factors that influence weathering?

A) Chemical weathering occurs fastest in cold or dry climates.
B) Whether a slope faces toward or away from the sun is not an important factor influencing weathering.
C) Soil and other weathering products tend to accumulate more on gentle slopes than on steep slopes.
D) Time is not a critical factor in weathering because physical and chemical processes have not changed much through time.

Question 17

How does the character of a rock influence weathering

A) Fractures and other discontinuities block the entry of water into a rock and so make the rock more resistant to weathering.
B) Minerals that are soluble can be dissolved and reprecipitated and so are resistant to weathering.
C) Rocks that are broken have more surface area and so weather faster.
D) Rocks that are easily weathered and eroded generally form steep cliffs.
E) None of these.

Question 18

The joints in the photograph mimic topography, indicating that they formed:

A) while the granite was still molten
B) while the rocks were still buried at great depth
C) when the weight of overlying rocks was unloaded, allowing expansion along the joints
D) along a subduction zone

Question 19

Which of the following is valid for how rocks weather?

A) quartz is very soluble during weathering at low temperatures
B) limestone weathers rapidly in wet climates but can form cliffs in dry ones
C) as a granite weathers, quartz rapidly decomposes into clay minerals
D) most minerals in granite weather at nearly the same rate and so granite has smooth surfaces

Question 20

What is the main reason why the oceans are salty?

A) the early oceans were salty because comets are dirty snowballs
B) salt deposits that formed early in Earth's history become dissolved by modern oceans
C) weathering of rocks releases chemical elements that make the oceans salty
D) blowing salt crystals become incorporated into clouds and falls with the rainfall

Question 21

Compared to a gentle slope, a steep slope will have a

A) faster rate of soil formation and less soil.
B) slower rate of soil formation and less soil.
C) faster rate of soil formation and more soil.
D) slower rate of soil formation and more soil.

Question 22

Which of the following features is composed of calcium carbonate?

A) limestone
B) travertine
C) cave formations like stalagmites
D) all of these

Question 23

In which setting is karst topography most likely to feature steep pillars, knobs, and oddly shaped rocks?

A) tropical
B) arid
C) mid-latitude
D) polar

Question 24

Which of these four numbered features on the surface or in a cave can be formed by the dissolution or collapse of limestone?

A) 1 and 2
B) 2 and 3
C) 3 and 4
D) 1 and 3
E) 1 and 4

Question 25

Which of the following is true about how weathering affects fractured rocks?

A) Weathering affects rocks from the outside in, forming an outer weathered zone or rind.
B) Weathering attacks corners from three sides and so these are preferentially removed.
C) Preferential weathering along fractures can cause blocks to become rounded.
D) D. All of these.

Question 26

What is the most common way in which sinkholes form?

A) a small explosion of methane gas from coal beds
B) a small explosion of CO₂ gas from dissolving limestone
C) a rising dome of salt finally reaches the surface
D) the roof of a cave collapses

Question 27

Which of the following generally is true about caves formed by dissolution?

A) acidic waters dissolve feldspar in granite, producing clay
B) groundwater removed material from limestone
C) hot geothermal waters introduce acids into shallow rocks
D) carbon dioxide rises from depth and dissolves calcite and clay

Question 28

Which of these four numbered features on the surface or in a cave are formed by the precipitation of calcium carbonate, due to the evaporation of water?

A) 1 and 2
B) 2 and 3
C) 3 and 4
D) 1 and 3
E) 1 and 4

Question 29

Why does weathering of granite bedrock produce rounded shapes?

A) the rounded shapes are pillows formed at depth in the granitic magma
B) weathering removes corners and edges, as in spheroidal weathering
C) burrowing animals eat away parts of the granite
D) roots rub against the edges of the granite

Question 30

Aside from limestone, which other kinds of rock types produce karst terrain?

A) evaporite rocks such as salt and gypsum
B) granite
C) sandstone
D) shale

Question 31

All other factors being equal, a slope facing away from the Sun will tend to have

A) faster soil formation than the slope in direct sunlight, primarily because chemical weathering processes will be accelerated.
B) faster soil formation than the slope in direct sunlight, primarily because physical weathering processes will be accelerated.
C) slower soil formation than the slope in direct sunlight, primarily because chemical weathering processes will be slower.
D) slower soil formation than the slope in direct sunlight, primarily because physical weathering processes will be slower.

Question 32

Which of these four numbered features on the surface or in a cave is a stalagmite?

A) 1
B) 2
C) 3
D) 4
E) none of these

Question 33

What rock type is the most common setting for caves formed by dissolution of a rock?

A) well-sorted sandstone
B) gray limestone
C) dark porous lava flows
D) gray granite
E) slate

Question 34

Lichens play a special role in chemical weathering by

A) weakening the hydrogen bond in water, making it more effective at dissolving rocks with high quartz concentrations.
B) slowing the rate of jointing in rocks.
C) acting as a catalyst for dissolution of minerals that crystallize at the highest temperatures.
D) secreting oxalic acid, which dissolves carbonates particularly well.

Question 35

Which sequence of events is required to form a limestone cave where you can walk around and observe cave formations, such as stalactites?

A) limestone is below the water table, then lowering of the water table, then water dripping from the ceiling
B) lowering of the water table, then water dripping from the ceiling, then limestone is below the water table
C) water dripping from the ceiling, then lowering of the water table, then limestone is below the water table
D) none of these

Question 36

Which of the following features is NOT formed by precipitation of calcite from water?

A) travertine
B) stalagmite
C) stalactite
D) sinkhole
E) flowstone

Question 37

Which of the following is a feature that commonly forms where limestone has been dissolved?

A) sinkhole
B) karst topography
C) cave
D) all of these

Question 38

Which of these four numbered features on the surface or in a cave is a stalactite?

A) 1
B) 2
C) 3
D) 4
E) none of these

Question 39

Which of the following is the best indication that limestone caves could be present at depth?

A) springs
B) cliffs and overhangs along rivers
C) large quartz crystals laying on the surface
D) gently sloping hills
E) limestone pillars and sinkholes

Question 40

Which of the following features is formed by the collapse of caves?

A) travertine
B) stalagmite
C) stalactite
D) sinkhole
E) flowstone

Question 41

What is the main process by which soils form?

A) deposition of silt on a floodplain
B) deposition of silt by the wind
C) weathering
D) erosion

Question 42

Which of the following are problems related to soil?

A) individual grains lose contact with one another as water squeezes between them
B) certain clay minerals increase in volume when they become wet
C) soils that do not compact uniformly because of varying amounts of clay
D) erosion due to loss of plant cover, such as from overgrazing
E) all of these

Question 43

Which of the following is an expression of the angle of repose?

A) talus slope
B) some slopes of sand dunes
C) angle of slopes on scoria cones
D) all of these

Question 44

Which of the following is NOT a source of material for soil?

A) weathered rock and sediment
B) leaves and other plant debris
C) CO₂ gas from roots
D) water from precipitation and snowmelt
E) all of these are a source of material in soil

Question 45

The largest area of karst in the United States is included in

A) Florida.
B) Mississippi.
C) Minnesota.
D) Texas.

Question 46

Soil that is reddish, intensely leached, and rich in iron and aluminum minerals most likely forms in:

A) tropical climate
B) temperate climate
C) arid climate
D) an area with only minor soil development
E) a short amount of time

Question 47

Which of the numbered soil horizons are most likely to represent an accumulation of organic debris?

A) 1 and 2
B) 2 and 3
C) 3 and 4
D) 4 and 5
E) all of these

Question 48

Which of the numbered soil horizons is most likely to have clay or calcium carbonate?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 49

A soil that has little or no O-horizon but a thick accumulation of calcium carbonate caliche) most likely forms in:

A) a tropical climate
B) a temperate climate
C) an arid climate
D) an area with abundant rainfall
E) a short amount of time

Question 50

Which of the following factors is typically NOT used to classify slope failures?

A) whether the material involved is rock or is unconsolidated
B) the rate of movement
C) the climate in which the failure occurs
D) the mechanism by which material moves

Question 51

Which of the numbered soil horizons is most likely to have remnants of weathered bedrock?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 52

People reshape steep slopes, a practice called terracing, in order to:

A) help capture and retain rainfall
B) provide a level place on which to farm
C) promote soil formation
D) protect soil from erosion
E) all of these

Question 53

What is the angle of repose?

A) the angle of bedding on hills where layers dip parallel to the slope
B) the angle of fractures on hills where fractures dip parallel to the slope
C) the angle at which rainfall strikes an unstable slope
D) the steepest angle at which loose material remains stable

Question 54

What is the main force involved in the stability of slopes?

A) water pressure
B) sunlight
C) wind
D) gravity
E) radioactivity decay

Question 55

The main feature shown in this photograph illustrates:

A) weathering
B) flooding
C) permafrost
D) slope failure

Question 56

How does material in soil move?

A) the upper part of soil loses material downward
B) clay minerals and other fine particles are carried downward
C) chemical ions leached from above can accumulate in the underlying zone
D) calcium carbonate can accumulate in the soil, especially in dry environments
E) all of these

Question 57

As illustrated in this figure, which of the following is NOT potential trigger for slope failure?

A) precipitation that can saturate and weaken sediment
B) undercutting of steep slopes by roads and rivers
C) shaking during an earthquake
D) shaking of slopes and melting of snow during volcanic eruptions
E) all of these are illustrated

Question 58

Which of the following is NOT a common trigger for slope failure?

A) adding water to a slope
B) volcanic eruption
C) shaking during an earthquake
D) oversteepening of cliffs or hillslopes during road construction
E) all of these are common triggers for slope failure

Question 59

How can weathering form a mineral deposit?

A) extreme leaching can leave behind elements, such as aluminum, that are valuable
B) weathering can dissolve copper from the top of a mineral deposit and reprecipitate it at depth
C) heavier materials, such as gold and diamond, accumulate near the base of river gravels
D) all of these

Question 60

Which of the following factors does NOT control the stability of a slope?

A) the angle of repose for intact bedrock
B) whether the slope is rock or soil
C) the amount of water in the soil
D) the orientation of fractures, cleavage, and bedding

Question 61

Which of the following is a way that slopes fail?

A) large blocks fall from cliffs
B) rocks, soil, sediment, and ice slides down steep hillsides
C) pieces of loose rock accumulate on talus slopes until the angle becomes too steep
D) soil and other loose material can flow rapidly down slopes, forming debris flows
E) all of these

Question 62

What type of slope failure is shown in this figure?

A) creep
B) debris flow
C) rock fall
D) rock slide
E) rotational slide

Question 63

Which of the following factors caused some high peaks of the Cascade Mountains of the Pacific Northwest to have high potential for slope failure?

A) they are volcanoes with steep slopes
B) they experience heavy rainfall
C) they may contain loose volcanic ash and other volcanic materials
D) all of these

Question 64

Which of the following slope failures is most likely to cause large numbers of casualties?

A) creep
B) debris slide
C) earth flow
D) rotational slide
E) rock avalanche

Question 65

What type of slope failure is depicted in this photograph?

A) creep
B) rock fall
C) debris avalanche
D) permafrost

Question 66

Which numbered feature on this figure is a scarp?

A) 1, a linear or curved scar marking where the slide pulled away from the hill
B) 2, small fractures within the sliding block
C) 3, the intact layers below the rock slide
D) 4, the front of the slide, where it overruns the land surface
E) 5, a valley or other open space in front of the slide

Question 67

The main feature shown in this photograph illustrates?

A) weathering
B) flooding
C) permafrost
D) slope failure

Question 68

What type of slope failure is shown in this figure?

A) rotational slide
B) creep
C) rock avalanche
D) debris flow
E) rock fall

Question 69

What factors lead to the Viaont landslide disaster?

A) a volcanic eruption shook the ground
B) a major earthquake shook the ground
C) the sedimentary layers dipped downslope toward the reservoir
D) all of these

Question 70

What type of slope failure is shown in this figure?

A) rotational slide
B) creep
C) earth flow
D) debris flow
E) rock fall

Question 71

What type of slope failure is shown in this figure?

A) rotational slide
B) creep
C) earth flow
D) debris flow
E) rock slide

Question 72

What type of slope failure is shown in this figure?

A) rotational slide
B) creep
C) debris slide
D) debris flow
E) rock fall

Question 73

Which of the following slope failures moves at the slowest rate?

A) earth flow
B) rock avalanche
C) debris flow
D) rock fall
E) debris avalanche

Question 74

The type of slope failure shown in this photograph is:

A) creep
B) a rock slide
C) a debris avalanche
D) a debris flow
E) all of these

Question 75

What type of slope failure is shown in this figure?

A) rotational slide
B) creep
C) earth flow
D) debris flow
E) rock avalanche

Question 76

Which of the following has the lowest potential for landslides?

A) Pacific Northwest
B) southern California
C) bluffs along rivers in the central U.S.
D) Florida
E) Appalachian Mountains

Question 77

Which numbered feature on this figure is critical to enable a rock slide to start?

A) 1, a linear or curved scar marking where the slide pulled away from the hill
B) 2, small fractures within the sliding block
C) 3, layers, fractures, or some other discontinuity inclined downslope
D) 4, the front of the slide, where it overruns the land surface
E) 5, a valley or other open space in front of the slide

Question 78

What type of slope failure is shown in this figure?

A) debris avalanche
B) creep
C) rock slide
D) debris flow
E) rock fall

Question 79

Which of the following factors favors movement of a rock slide?

A) layers that are inclined opposite to the slope of the hill
B) solid rock with few preexisting joints or faults
C) a massive rock with no bedding or other through-going discontinuities
D) a valley or other open space downslope from the rock slide

Question 80

Which of the following slope failures is least likely to cause casualties?

A) rock avalanche
B) debris flow
C) creep
D) rock slide
E) rock fall