Deck 5: Weathering and Soil

Question 1

In nature, where does the acidity come from to speed up chemical weathering?

A)nuée ardentes from explosive volcanic eruptions
B)Bowen's reaction series
C)plutonism
D)organic acids from decayed plants, acid rain, and sulphuric acid from oxidation of pyrite

Answer 1

D

Question 2

Which one of the following statements is false?

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

Answer 2

D

Question 3

________ is the dissolution or decomposition of minerals and rocks.

A)Chemical weathering
B)Hydrolysis
C)Mechanical weathering
D)Rendering

Answer 3

A

Question 4

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 5

The three major processes involved in chemical weathering are ________.

A)carbonation, dissimulation, and salinization
B)dissolution, hydrolysis, and oxidation
C)precipitation, ion exchange reactions, and degasification
D)recrystallization, pitting, and rinsing

Question 6

As ________ increases the surface area of a rock or mineral, this allows ________ to occur at a faster rate.

A)chemical weathering, mechanical weathering
B)infernal weathering, mechanistic weathering
C)mechanical weathering, chemical weathering
D)recrystallization, carnal weathering

Question 7

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 8

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

A)tropical laterites
B)talus slopes
C)C soil horizons
D)lunar soils

Question 9

The physical removal of dissolved or disaggregated rock from the site of weathering by wind, water, or ice is termed ________.

A)ablation
B)erosion
C)recidivism
D)solifluction

Question 10

The downslope transfer of loose rock and soil particles by the force of gravity is called ________.

A)gravity
B)mass wasting
C)mass migration
D)slopewash

Question 11

Which term best describes an accumulation of angular rock fragments at the base of a steep, bedrock slope or cliff?

A)bajada
B)fanglomerate
C)rock and roll
D)talus slope

Question 12

________ is the great reduction in pressure from erosion and it leads to the formation of ________ in mountainous exposures of granitic batholiths.

A)Relief, horns or tinds
B)Offloading, deep valleys
C)Flatulence, plateaus
D)Sheeting, exfoliation domes

Question 13

Which one of the following statements is the best description of 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 14

The principal causes of mechanical fragmentation of rocks in place are ________.

A)always inscrutable because they happened at some time in the past
B)biologic activity, expansion from sheeting, frost wedging
C)erosion and transport by moving wind, water, or ice
D)the relentless actions of Sisyphus

Question 15

________ are regularly spaced planar fracture sets in rocks that result from: expansional unloading, tectonic forces, or thermal contraction upon cooling (especially igneous rocks).

A)Cracks
B)Faults
C)Fissures
D)Joints

Question 16

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 17

Dissolution of minerals occurs because most minerals are ionic crystals and ________.

A)their bonds eventually wear out
B)water molecules are strongly polarized, effectively competing with ionic bonds
C)water selectively removes all of their smaller anions
D)water selectively absorbs all of their electrons until the crystals fall apart

Question 18

Which term best describes those processes that move weathered rock materials and soils downslope?

A)podzolization
B)slope sheeting
C)mass wasting
D)talus transfer

Question 19

Which are examples of Earth's external processes?

A)compaction, dewatering, and cementation of sediments
B)erosion, weathering, and mass wasting
C)radioactive decay, convection, and recrystallization
D)volcanism and mountain building

Question 20

Assume that water filling a crack in a rock undergoes cycles of freezing and melting.Which of the following statements 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 21

What mineral particles are the dominant colouring agents in reddish, brownish, and yellowish soils?

A)soluble potassium and sodium bicarbonates
B)humus and calcium carbonate
C)very fine-sized silica and calcite particles
D)dust-sized grains of iron oxides

Question 22

________ is the most common mineral breakdown product of KAlSi?O? (potassium feldspar).

A)Asbestos
B)Calcite
C)Kaolinite
D)Quartz

Question 23

Hydrolysis is ________ to weaken or destroy the mineral lattice.

A)the dissolution of minerals by water
B)the replacement of mineral cations by hydrogen ions from solution
C)the conversion of useless minerals to hydrogen gas
D)the chemical removal of bonded hydrogens

Question 24

In which of the following climates would rates of chemical weathering generally be highest?

A)warm and moist
B)cold and dry
C)warm and dry
D)cold and moist

Question 25

Which of the following statements about acidic precipitation is false?

A)Chemical weathering and deterioration of exposed rock and metal surfaces will accelerate if acidic precipitation increases.
B)Acid precipitation from industrial sources has almost been eliminated and is no longer a concern for the environment.
C)Fish and other aquatic species in acidified lakes will eventually die off and disappear due to the toxic effects of the acidic waters and increased levels of dissolved aluminum.
D)Damage to trees and plants, especially to tender new growth, will intensify if acidic precipitation worsens.

Question 26

Ordinary chemical weathering of rock forming minerals like feldspar and amphibole produces ________.

A)dissolved clays and iron hydroxides
B)all of the sodium and chloride ions that make the salt content of the seas
C)solid residues of quartz and reduced iron compounds
D)soluble silica and ions (Ca?², Na?, Mg?² )plus residues of clay minerals

Question 27

What portion of an angular, fracture-bounded granitic block shows the highest rate of weathering?

A)the unfractured interior
B)the exposed edges and corners
C)the crack surfaces not including edges and corners
D)the middle of faces bounded by a single large fracture

Question 28

Which of the following is/are most susceptible to chemical weathering by dissolution?

A)quartz
B)clay minerals
C)iron oxides
D)calcite

Question 29

How long do the acid generating gases from fossil fuel combustion remain in the lower levels of the atmosphere and how far do they travel?

A)less than a few hours; a few kilometres
B)a few hours to a few days; up to several thousand kilometres
C)weeks to months; only locally
D)several years; around the world

Question 30

Which of the following best explains why angular, crack-bounded, granitic blocks weather to spheroidal boulders?

A)Weathering agents have more direct access to edges and corners than to other parts of the block.
B)Interiors of blocks are constantly damp or wet because sunlight cannot penetrate.
C)Crack surfaces of blocks heat and cool more rapidly than edges and corners.
D)They slowly roll over in place and wear off the corners first.

Question 31

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 32

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

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

Question 33

Which would make the longest lasting headstone for Granny's grave in "Peaceful Acres" on the east side of Toronto?

A)a polished, fine grained basalt
B)a large rough limestone slab from a quarry near Kingston
C)a coarse-grained grey granite
D)a pink Precambrian quartzite

Question 34

How do large, spheroidal boulders form from massive bedrock?

A)Exfoliation breaks a fresh, spherical block from the bedrock.
B)A fresh rock slab is broken out along sheeting fractures and then rounded by residual laterization.
C)An angular block, broken away from bedrock, gets rounded by rolling down a slope.
D)The corners and edges of fracture-bounded blocks are weathered faster than the planar areas of the fracture surfaces.

Question 35

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

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

Question 36

What chemical weathering process associated with surface mining activities is a major environmental hazard?

A)coal oxidation
B)oxidation of pyrite and other sulphides to produce "mine acid" or acid rock drainage
C)recurrent landslides from unstable talings piles
D)release of oxidized mine gases

Question 37

What oxidized iron bearing minerals generally form as the residue of weathering?

A)ferrous feldspars
B)goethite, hematite, and limonite
C)pyrite and native iron
D)olivine, pyroxene, and amphibole

Question 38

What two chemical constituents cannot form by chemical weathering of the feldspar minerals alone?

A)soluble sodium and potassium bicarbonates
B)insoluble iron oxides and soluble magnesium bicarbonates
C)silica and insoluble clay minerals
D)silica and soluble calcium bicarbonate

Question 39

Clay minerals, silica (SiO?), and dissolved potassium bicarbonate in the soil water are products of which process?

A)chemical weathering of olivine and plagioclase feldspar
B)mechanical weathering of granite and rhyolite
C)chemical weathering of orthoclase feldspar
D)differential mechanical weathering of micas

Question 40

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 41

Which of the following statements about laterites or tropical rainforests is true?

A)Laterite soils readily compact and harden when dried and exposed to sunlight.
B)Rainforests regenerate quickly following clear cutting or clearing for agriculture.
C)Laterite soils are very rich in nutrients required for vigorous plant growth.
D)Laterites, with proper management, are very suitable for commercial agriculture.

Question 42

Lateritic soils form under what climatic conditions?

A)warm and moist as in a wet, tropical forest
B)cool and relatively dry as in Nunavut
C)hot and dry as in the desert regions of North Africa and Arabia
D)moist and temperate as in southwest BC

Question 43

Which of the following best describes the "Dust Bowl"?

A)the long drought preceding the Irish potato famine of the 1840s
B)the area covered by volcanic ash around Mount Merapi in 2010
C)areas of severe wind erosion on the Prairies, 1930s
D)a New Year's Day invitational soccer match in Tripoli, Libya

Question 44

Which of the following best describes the process of eluviation?

A)Percolating water removes 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 45

Which of the following statements concerning humus is false?

A)is typically found above the B soil horizon
B)consists of decaying and partly decayed leaves and other plant materials
C)is readily leached from the B horizon in weakly acidic, soil solutions
D)is less abundant in wet, tropical, forested areas than in temperate, forested areas

Question 46

In which area are pedocal soils most likely to be found?

A)a tropical rainforest in the Amazon Basin of Brazil
B)a bitterly cold, permafrost area in north-central Siberia
C)a forested area of SE Manitoba
D)a moderately dry to semiarid grassland such as SW Saskatchewan

Question 47

Caliche is an excessive accumulation of ________.

A)calcite in the E horizon of a pedalfer
B)clays in the A horizon of a laterite
C)clays in hardpan layers of a pedocal
D)calcium carbonate in the B horizon of a pedocal

Question 48

Where would you be best advised to attempt large scale, natural plantations of a popular broad-leafed recreational plant that could thrive untended in a pedalfer (podzol)with a temperate climate and enough rain?

A)BC or the Maritimes
B)Alberta
C)Manitoba
D)Saskatchewan

Question 49

Which of the following describes a characteristic process in the formation of a pedalfer soil?

A)Soil bacteria produce organic acids that precipitate calcium carbonate in the B horizon.
B)Iron oxides and aluminum-rich clays are precipitated in the B horizon.
C)Humus accumulates below the solum in the C horizon.
D)Clays are eluviated upward from the C horizon.

Question 50

Which is the common soil formed in dry young forest with long winters as in Yukon?

A)brunisol
B)cryosol
C)gleysol
D)podzol

Question 51

Which of the following statements concerning lateritic soils is generally false?

A)They form in warm, moist, tropical climates.
B)They are mainly red in colour.
C)They remain highly productive agriculturally without additions of fertilizers.
D)They consist of only the most insoluble, soil-forming minerals such as iron oxides, aluminum oxides, and clays.

Question 52

What is the common soil formed in semi-arid grassland with alkali and salt tolerant plants as in SE Alberta and SW Saskatchewan?

A)solonetzic and pedocal
B)cryosol
C)chernozem
D)luvisol

Question 53

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

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

Question 54

What is represented by the A, E, B, and C soil horizons in luvisol, podsol, or chernozem?

A)an in situ response to an extended period of weathering
B)primary, depositional layering in a transported soil
C)multiple caliche horizons
D)buried humus layers

Question 55

Which of the following best describes the A soil horizon?

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

Question 56

Which one of the following statements concerning soil erosion is false?

A)Sheet erosion, rills, and gullies develop mainly during prolonged droughts.
B)Soils form naturally by weathering; if protected from erosion, sound management can maintain or enhance their nutrient levels and textural characteristics.
C)Rates of soil erosion exceed rates of soil formation in some parts of the world.
D)Grasses and other vegetation, windbreaks, and contour cropping will help reduce losses of soil from cultivated lands.

Question 57

Which of the following affects both the kind of soil and its rate of formation?

A)type of vegetation cover
B)meteorite showers
C)sun spot activity
D)plants and animals, climate, and parent material

Question 58

What is the common soil formed in moist, temperate areas like most of Quebec and the Maritimes?

A)pedalfer (podzol)
B)cryosol
C)chernozem
D)luvisol

Question 59

Why is the humus layer typically thicker in a cool, temperate, forest soil than in a tropical rainforest soil?

A)Less humus is produced in the tropical rainforest because the B horizon is so poorly developed.
B)Less humus is produced in the cool, temperate forest but the rate of decay and oxidation is slower than in a tropical rainforest.
C)More humus is produced in the tropical rainforest, but it is quickly washed away by the heavy rains.
D)In a tropical rainforest, the forest-floor litter is often burned during the dry season.

Question 60

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

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

Question 61

Weathering generally accentuates the differences in minerals and rocks, serving to sculpt unusual shapes and spectacular landscapes.

Question 62

Weathering only acts on naturally occurring rocks and minerals, not on man made substances like concrete, glass, metal, or plastic.

Question 63

Very fine-grained, iron oxide particles account for nearly all red, yellow, and brown soil colours.

Question 64

Frost wedging is an important process for enlarging cracks and extending them deeper into the bedrock.

Question 65

Chemical weathering of pyrite in a wet environment produces H?SO?.

Question 66

Like most other liquids, water decreases in volume when it freezes.

Question 67

Mechanical weathering involves rock materials being broken into smaller particles.

Question 68

Oxidation of iron is an important chemical weathering process for ferromagnesian silicate minerals like olivine and biotite.

Question 69

Sheeting parallel to quarry floors, and rock bursts on fresh cuts and tunnels, are caused by unloading.

Question 70

One of the chief detriments to the environment by acid rain is the acidification of lakes.

Question 71

Rocks always weather chemically before they undergo mechanical weathering.

Question 72

The addition of a small amount of acidity dramatically increases rates of dissolution and chemical weathering.

Question 73

Sheeting fractures and exfoliation domes commonly develop in areas with soft, highly fractured bedrock.

Question 74

Thermal cooling, especially of igneous rocks, results in the formation of regular patterns of joints.

Question 75

Sheeting is mainly a process of mechanical weathering.

Question 76

Oxidation of iron in ferromagnesian minerals and dissolution of calcite are two examples of mechanical weathering.

Question 77

Release of carbon, nitrogen, and sulphur oxides from burning fossil fuels causes precipitation that is far more acidic than natural rain.

Question 78

Minerals which undergo oxidation must lose electrons during this process.

Question 79

Weathering is considered an internal process, because it involves chemical changes in minerals.

Question 80

The natural decomposition of limestone through chemical weathering mostly produces solid, insoluble calcium hydroxide.