Deck 4: Weathering, soil, and Mass Wasting

Question 1

Which of the following is most resistant to both chemical and physical weathering?

A)clay minerals
B)quartz
C)a granite
D)a limestone

Answer 1

B

Question 2

The finely divided,red,brown,and yellow soil-coloring minerals originate by what process?

A)mechanical weathering of very fine-grained,blue-gray clays
B)chemical weathering of quartz and feldspars
C)precipitation of iron oxides during the chemical weathering process
D)mechanical weathering of the feldspars and micas in granite and rhyolite

Answer 2

C

Question 3

Rounding of angular edges of rock outcropping and formation of insitu,spherical boulders are both indications of ________.

A)chemical weather and associated spheroidal weathering
B)rock fall onto sharp edges breaking of angular corners of rock outcrops
C)dissolution of the rock surface by acid rain
D)humans and animals walking across the Earth's surface,wearing away the surface

Answer 3

A

Question 4

Which one of the following is an important,mechanical weathering process for enlarging fractures and extending them deeper into large boulders and bedrock?

A)oxidation
B)eluviation
C)hydrologic cycling
D)frost wedging

Question 5

Centuries ago quarrymen learned that when quarrying granite it was usually easiest to break the rock along a nearly horizontal surface.We now know this arises because ________.

A)uplift and exhumation of granites produces an unloading,which produces sheeting joints like the quarrymen used
B)frost wedging for hundreds of thousands to millions of years have produced cracks parallel to the ground surface
C)chemical weathering of granite makes the material expand,pulling it away from the underlying rock
D)it was a false observation; the quarrymen in those days couldn't measure resistance,and it just seemed easier to wedge blocks of this type

Question 6

In which area would weathering by frost wedging probably be most effective?

A)in a moist,tropical forest
B)in cool high desert areas
C)where the subsoil is permanently frozen
D)in moist,temperate climates

Question 7

What two factors speed up rates of chemical reaction and weathering in rocks and soils?

A)low temperatures; very dry
B)low temperatures; very moist
C)high temperatures; very dry
D)warm temperatures; very moist

Question 8

Under similar warm,moist climatic conditions,why would basalt and gabbro generally have higher chemical weathering rates than rhyolite and granite?

A)The quartz in the gabbro and basalt decomposes very quickly.
B)The ferromagnesian minerals in the gabbro and basalt are subject to oxidation and chemical breakdown.
C)The plagioclase feldspars in the granite and rhyolite decompose readily to clay minerals and iron oxides.
D)The potassium feldspars and quartz in the rhyolite and granite are more susceptible to cracking by frost wedging.

Question 9

Assume that water filling a crack in a rock undergoes cycles of freezing and melting.Which of the following statement is true?

A)Water expands as it melts,causing the crack walls to be pushed apart.
B)Water shrinks as it freezes,causing the crack walls to be drawn closer together.
C)Water expands as it freezes,causing the crack walls to be pushed apart.
D)Water shrinks as it melts,causing the crack walls to be pulled closer together.

Question 10

Mass wasting,a process that often occurs between weathering and erosion,involves ________.

A)the chemical dissolution of minerals due to water
B)the mechanical breakdown of minerals due to exposure to the Sun and atmosphere
C)the transport of material by water,wind,or ice
D)the transport of material due to gravity

Question 11

What is the major distinction between internal and external Earth processes?

A)Internal processes involve heat,and external processes involve oxygen.
B)Internal processes are driven by things like Plate Tectonics,and external processes are driven by the sun.
C)Internal processes can only occur inside the Earth,but external processes can occur inside or outside the Earth.
D)Internal and external processes can occur inside and outside the Earth,but external processes must also include the oxidation of Earth materials.

Question 12

One important relationship between chemical and mechanical weathering is ________.

A)chemical weathering can produce smaller pieces of rock that can then be modified by mechanical weathering
B)chemical weathering can form brittle materials that are easily broken into smaller pieces by mechanical weathering
C)mechanical weathering can produce smaller pieces of rock that have more surface area for chemical weathering to work on.
D)mechanical weathering forms more brittle materials that are easily broken down by chemical weathering.

Question 13

Clay minerals formed from gabbro or diorite bedrock illustrate which kind of weathering?

A)chemical
B)proactive
C)syntropical
D)mechanical

Question 14

All of the following are factors that affect rates of weathering except for ________.

A)rock characteristics
B)surface area
C)climate
D)geologic age of earth materials

Question 15

Which one of the following statements concerning mechanical weathering is not true?

A)reduces grain sizes of rock particles
B)allows for faster rates of chemical weathering
C)is important in the formation of talus slopes
D)involves a major change in the mineral composition of the weathered material

Question 16

Which of the following is not a physical weathering process?

A)frost wedging
B)salt crystallization
C)tree root growth
D)rocks reacting with organic acids from plants

Question 17

Chemical weathering rates are highest in ________.

A)hot dry climates
B)hot wet climates
C)cold wet climates
D)cold dry climates

Question 18

Which one of the following statements best describes erosion?

A)disintegration and decomposition of rocks and minerals at the surface
B)movement of weathered rock and regolith toward the base of a slope
C)the process by which weathered rock and mineral particles are removed from one area and transported elsewhere
D)the combined processes of leaching,eluviation,and mass wasting

Question 19

Which of the following best describes sets of fractures in relatively fresh bedrock,such as granite,that are roughly parallel to the land surface?

A)thermal expansion cracks
B)sheeting fractures
C)hydrolytic failures
D)columnar joints

Question 20

Frost wedging is the major weathering process contributing to the formation of which regolith material?

A)tropical soils
B)talus slopes
C)soil horizons
D)clay minerals

Question 21

A soil that has nearly equal amounts of clay,silt and sand is called ________.

A)loam
B)lane
C)clayey
D)rich

Question 22

Which term describes a soil formed by weathering of the underlying bedrock?

A)transformational
B)residual
C)relict
D)transported

Question 23

The word topsoil is commonly used,but not always correctly.The proper definition is ________.

A)the A,E and B horizons
B)the dark,organic rich layers of O and A
C)the entire soil down to the base of the C horizon
D)only the O horizon

Question 24

Limestone and marble weather faster than granite because ________.

A)granite is more resistant to physical weathering because of its large crystals
B)limestone has many cracks and holes that allow water to infiltrate and weather the rock
C)limestone and marble can be dissolved by weak acids in rain
D)granite does not react with rainwater and only weathers by physical erosion

Question 25

As an erosional process,how is mass wasting unique compared to wind,water,and ice?

A)Mass wasting affects particles of all sizes whereas the others affect only smaller particles.
B)Mass wasting does not require a transporting medium.
C)Mass wasting affects much larger geographic areas than does wind,water,and ice.
D)All of the above make mass wasting unique compared to wind,water,and ice.

Question 26

Soil classifications,like biological classifications,use a taxonomy.The first syllable(s)gives a descriptive term and last syllable is ________.

A)sol
B)soil
C)solt
D)drt

Question 27

From the land surface downward to the unweathered bedrock,which of the following is the correct order of the different soil horizons?

A)0,A,E,B,C,bedrock
B)A,B,C,D,E,bedrock
C)E,A,B,C,0,bedrock
D)D,E,C,B,A,bedrock

Question 28

Which type of soil would typically be the richest soil?

A)transported
B)residual
C)upland slope
D)desert

Question 29

Which soil horizon represents the uppermost limit of the zone of accumulation,also referred to as the subsoil?

A)A
B)B
C)C
D)E

Question 30

Organisms contribute to soils formation by ________.

A)contributing organic matter to the soil
B)degrading organic matter to form humus
C)stirring the soil to allow air infiltration
D)all of the above

Question 31

Given enough time,what factor is typically most important in soil formation?

A)bedrock type
B)slope direction
C)climate
D)months of snow cover

Question 32

In much of what is now Canada,glaciers covered the land as little as 12,000 years ago and glacial erosion scoured the land surface leaving very thin soil or bare rock over large areas.The Midwestern United States was also covered in ice at this time,yet this area contains some of the richest farm land in the world with thick soils.These soils are formed on glacial sediments and windblown dust deposits from the ice age.Why are the soil conditions between these areas so different when the soils are virtually identical in age?

A)It is much colder in Canada so chemical weather is much slower; thus and soils have not had time to form.
B)The Midwestern soils are transported soils with soil development on materials that were already loose,unconsolidated materials.
C)Sea level rose following the ice age and covered the Midwest with an inland sea,rapidly forming soil.
D)The Midwestern U.S.is much flatter than Canada,allowing soils to develop more quickly.

Question 33

Deforestation of rain forests exposes tropical soils that are famous for their low fertility,despite the fact that they had previously hosted a lush tropical forest.Which soil type would describe these soils?

A)Andisols-young soils formed on volcanic ash and volcanogenic sediment
B)Vertisols-Soils containing large amounts of clay,which shrink upon drying and swell with the addition of water.Found in subhumid to arid climates
C)Histosols-Organic soils with little or no climatic implications.Can be found in any climate where organic debris can accumulate to form a bog soil.Dark,partially decomposed organic material commonly referred to as peat
D)Oxisols-Soils that occur on old land surfaces unless parent materials were strongly weathered before they were deposited.Rich in iron and aluminum oxides,Oxisols are heavily leached,hence are poor soils for agricultural activity

Question 34

Which of the following best describe the E soil horizon?

A)regolith zone
B)erosion zone
C)residual zone
D)leaching zone

Question 35

Deep soils are characteristic of tropical regions whereas thin rocky soils are characteristic of high latitudes.This is a natural demonstration that ________.

A)chemical wreathing rates are much higher in the tropics than high latitudes
B)physical weathering and erosion rates are higher at high latitude,removing soil faster than it can form
C)all of the high latitude regions lost their soil in recent times
D)humans living at high latitudes have destroyed the soils by bad farming practices

Question 36

Engineers refer to any loose material on the surface of the Earth as soil.How does this differ from the definition used in Earth sciences?

A)There is no difference,the definition is the same.
B)Earth scientists use the term soil only for the organic part of the surface materials.
C)Earth scientists only use the word soil to refer to the inorganic part of weathered,surface materials.
D)An engineer's "soil" is equivalent to what Earth scientists call regolith; soil has a more specific meaning.

Question 37

In the Rocky Mountain region of the United States,north-facing slopes (downhill direction is toward the north)are typically moister and more heavily forested than south-facing slopes.Why?

A)North-facing slopes receive more sunlight in the summer; snow melts faster and more soil moisture is available for the trees.
B)South-facing slopes receive more moisture and sunlight; rock weathering is slower.
C)North-facing slopes receive about the same amount of precipitation as south-facing slopes; less moisture evaporates from north-facing slopes.
D)South-facing slopes receive less moisture,yet rock weathering is faster.

Question 38

Features like rock ledges in badlands or rock fins standing above adjacent valleys are all examples of ________.

A)glacial erosion
B)river erosion
C)differential weathering
D)chemical weathering

Question 39

Digging downward through a soil profile,how deep would you have to go before you found recognizable fragments of the parent rock for the soil?

A)A
B)B
C)C
D)E

Question 40

Which of the following best describes the process of eluviation?

A)removal of very fine-sized silt and clay particles from the A and E soil horizons
B)buildup of calcite in the B-horizon of pedocal soils
C)removal of soluble chemical constituents from the A and B soil horizons
D)feldspar decomposition and leaching of the soluble products from the C soil horizon

Question 41

Landslides commonly occur when hurricanes hit steep terrain.Why?

A)Heavy rain from the tropical system can saturate slopes,triggering mass wasting events like mudslides.
B)The high winds produce a shear stress on the slopes,triggering mass movements.
C)The high winds uproot trees,weakening the slope and inducing mass wasting.
D)The correlation with hurricanes is coincidental.

Question 42

You live in a seismically active area and there are steep mountain slopes that show evidence of past large landslides.A geologist uses radiocarbon dating and determines that all of the landslides are 1000 +/- 5 years old.He also determines that there is an active fault in the area that moved in the last 1000-2000 years but he can't date it precisely.Which of the following is a reasonable conclusion?

A)Radiocarbon dating is not a good dating technique or it could separate the ages of the slides.
B)There was probably an earthquake ~1000 years ago.
C)There must have been a major drought 1000 years ago that triggered the landslides.
D)There must have been people in the area 1000 years ago,and they cut down the trees that were dated for determining the age of the landslide.

Question 43

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 increase as the slope angle is lessened.
B)It will decrease as the slope angle is lessened.
C)It is not affected by the slope angle.
D)It will possibly increase or decrease as slope angle is lessened,depending upon other factors.

Question 44

The mass wasting process in steep mountain areas that causes accumulations of rock debris called talus is called ________.

A)a slump
B)a rock avalanche
C)a rock fall
D)a rock slide

Question 45

In terrain with steep hill slopes,which crop and cultivation technique will minimize soil erosion?

A)corn; rows trending straight down the slope,frequent cultivation
B)apples; land between the trees is planted in grass and not cultivated
C)winter wheat; after the harvest,the field is plowed and left idle until next fall
D)bean; rows are spaced wider than on a level field

Question 46

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

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

Question 47

In North America "no till farming" has become a widespread practice made possible by genetically modified (GM)crops that can be sprayed with herbicide that kills everything but the GM plant.Evaluate the following statements on the role of GM crops on soil conservation issues?

A)They are a disaster.By killing all plants except the GM organism they expose the soil to increased erosion.
B)They have no effect one way or the other on soil erosion.
C)The no till practice dramatically improves soil conservation by providing loose organic matter cover to the soil surface,breaking up wind and runoff,lowering erosion rates.
D)The herbicides kill beneficial plants and animals and eventually will make the soil sterile.

Question 48

Which of the following is not a significant factor triggering mass wasting events?

A)heavy rainfall
B)earthquake
C)forest fire
D)mine tailings filling a valley

Question 49

A mass wasting process that involves rapid down-slope movement of debris aided by a cushion of air is called ________.

A)a slump
B)a rock avalanche
C)a rock fall
D)a rock slide

Question 50

Haiti is a mountainous island nation that has terrible problems with landslides.Which of the following explanations would best explain the problem?

A)Climate change has increased weathering rates on the island.
B)The area is hit by numerous tropical cyclones.
C)Most of the forests have been cut down for charcoal,leaving barren slopes subject to mass wasting during heavy tropical rainstorms and earthquakes.
D)The corrupt government has made poor roads subject to slope failure.

Question 51

A mass wasting process that involves rotational motion of material sliding above a distinct slip surface is called ________.

A)a slump
B)a rock avalanche
C)a rock fall
D)a rock slide

Question 52

A rancher overgrazes his land in an area underlain by heavy clay soils and regolith developed from weathering of claystone.After a series of heavy rains small creeks develop deep gullies along their length.A light steady rain develops and continues for several days.What should the rancher be concerned about on his overgrazed lands?

A)rock avalanche
B)slumps along the creeks
C)lahars filling cascading down his creeks,wiping out his cattle
D)increasing gully development because of the rain

Question 53

Most insurance companies will not insure property with a known landslide hazard.Why?

A)The risk is negligible on human time spans,but they are unwilling to take the risk because of liability.
B)The risk is high on human life time scales,and the hazard is difficult to assess.
C)They are known to always occur during major disasters like earthquakes and hurricanes,and they don't want the exposure to a large disaster.
D)They are just being cheap.

Question 54

A mass wasting process that involves slip of solid rock above a distinct sliding surface is called ________.

A)a slump
B)a rock avalanche
C)a rock fall
D)a rock slide

Question 55

Climate change and human activity like overgrazing of grasslands is leading to large areas subject to "desertification" where native grass cover dies out during drought periods,exposing soil to erosion.What is potentially the greatest initial soil erosion potential during this type of an event?

A)loss of topsoil by wind erosion on a large scale
B)local gullying produced by intermittent rain storms
C)sand blown in from adjacent deserts
D)growth of shrubs shading the ground,further killing the grasses

Question 56

Most stream valleys have a V shaped cross section because ________.

A)water washing down the slope makes straight channels.
B)vegetation on the slopes forces this profile.
C)mass wasting of weathered rocks on the slope maintain an angle of repose slope.
D)none of the above

Question 57

Water runoff is a major factor in soil erosion,what is a common land use practice on slopes to minimize soil erosion?

A)planting trees
B)adding a rock mulch layer to slow water runoff
C)planting row crops with rows running downhill,to minimize channelization of flow
D)terracing slopes to stop downslope runoff and rill formation

Question 58

You buy land in the tropics on steep mountain slopes covered by large trees and deep soil.You want to build a house on the land.Which of the following building plans is a very bad idea because of the danger of triggering mass wasting?

A)Excavate a flat bench on the slope for the house,pushing the debris to the slope below and leave a cut bank above the flat bench with grass planted on the steep slope.
B)Excavate the soil from the building site,install drainage systems,and backfill with gravel to prevent water accumulation.
C)Terrace the slope,building on the terraces,and constructing a rock retaining well with voids to allow drainage of water.
D)Sell the land because it will always be prone to mass wasting.

Question 59

How does deforestation by fire or human activity contribute to mass wasting?

A)It allows excess rainfall runoff to erode the landscape,triggering mass wasting.
B)It kills tree roots that help hold the slopes in place,allowing mass movement.
C)It allows the wind to blow across the slopes,imparting a stress that triggers landslides.
D)It allows farming activity that exposes soil to erosion and mass wasting.

Question 60

After the drought of the 1930's farmers in the Great Plains were encouraged to plant rows of trees across fields to decrease soil erosion.How would this reduce soil erosion?

A)Tree roots would retard runoff and prevent erosion.
B)The trees can serve as windbreaks to slow wind erosion.
C)The trees helped shade the ground,retaining moisture.
D)The trees had no effect; they were just used to improve the land appearance after the great depression.

Question 61

Which of the following statements concerning mudflows is not true?

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

Question 62

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

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

Question 63

Which of the following poses the greatest risk of massive loss of life and property along its path?

A)slump
B)earthflow
C)rock avalanche
D)rock fall

Question 64

In the late 1950's the Hebgen Lake earthquake outside of Yellowstone triggered a mass wasting event.The landslide originated on steep mountains slopes where rocks slid off a surface and descended to the valley floor in a few seconds,burying a campground and many people staying there.This type of landslide would be called ________.

A)a slump
B)a mudflow
C)a rockslide
D)an earthflow

Question 65

Which statement best describes slumping,a mass wasting process?

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

Question 66

Which mass wasting process has the slowest rate of movement?

A)slump
B)rock avalanche
C)rock fall
D)creep

Question 67

________ involves movement on a zone of compressed air.

A)A slump
B)A mudflow
C)A rock avalanche
D)Soil creep

Question 68

A geologist is looking at deposits along a river below a large volcano.She finds large boulders mixed with sand and mud,and all of the material is comprised of volcanic rocks,particularly the mud which is volcanic ash.She quickly realizes these deposits represent an ancient ________.

A)earthflow
B)rock avalanche
C)slump
D)lahar

Question 69

In deserts of southwestern North America developers often build houses in dry stream beds and build only minimal subsurface drainage systems to handle a flow of water comparable to the size of the dry stream channel.Is this a reasonable development model in the interest of public safety?

A)Yes,although flash floods can occur,using the channel size is a reasonable estimate of the maximum flood size.
B)No,flash floods can produce high viscosity mudflows that would not be captured by the drainage system and could flow out over the valley,destroying everything in its path.
C)No,giant rock avalanches could come down the valley covering houses.
D)Yes,any potential flooding catastrophe would be a 100 year flood event and would have adequate warning to evacuate people for safety,so the drainage system is adequate.

Question 70

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

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

Question 71

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

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

Question 72

What is the greatest danger from earthflow?

A)loss of life by rapid downslope movement of the earthflow
B)loss of property along the path of the earthflow
C)loss of water quality by mud flowing into river drainages,polluting the water
D)deforestation along the earthflow path

Question 73

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

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

Question 74

C-horizon A horizon E horizon B horizon

Question 75

oxidation dissolution hydrolysis sheeting

Question 76

Of the following,which one would most likely be triggered by an earthquake?

A)solifluction
B)soil creep
C)slump
D)rock avalanche

Question 77

________ denotes the exposed,crescent-shaped rupture surface at the head of a slump.

A)Scoop
B)Sole
C)Toe
D)Scarp

Question 78

The most rapid type of mass movement is a ________.

A)slump
B)lahar
C)rock avalanche
D)debris flow

Question 79

Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.

-wind water mass wasting ice

Question 80

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

A)rock avalanche
B)solifluction
C)soil creep
D)mudflow