Earth: An Introduction to Physical Geology, 11e (Tarbuck)
Chapter 6 Weathering and Soil
6.1 Multiple-Choice Questions
1) ________ is when physical forces break solid rock into smaller sediments.
A) Mechanical
B) Chemical
C) Spheroidal
D) Differential
2) ________ is when there is a chemical transformation of rock into other compounds.
A) Mechanical
B) Chemical
C) Spheroidal
D) Differential
3) Which of the following is not an agent of erosion?
A) Running water
B) Heat
C) Ice
D) Wind
4) Which of the following regions is not likely to experience weathering via salt crystal growth?
A) Arid deserts
B) Rocky shorelines along the ocean
C) Subterranean cave passages
D) Roadways cleared of snow through the spread of sodium chloride
5) What environmental condition is reduced on a batholith in order to generate weathering via
sheeting?
A) Heat
B) Moisture
C) Pressure
D) Mineral content
6) What is the most important agent of chemical weathering?
A) Salt
B) Heat
C) Wind
D) Water
7) Which acid is commonly responsible for the dissolution of limestone?
A) Nitric
B) Carbonic
C) Sulfuric
D) Hydrochloric
8) Which chemical weathering process is the primary method of weathering for feldspars?
A) Dissolution
B) Oxidation
C) Frost Wedging
D) Hydrolysis
9) Rainwater will combine with which atmospheric gas in order to create carbonic acid?
A) Methane
B) Oxygen
C) Carbon Dioxide
D) Carbon Monoxide
10) ________ and ________ are chemical weathering products created in many metallic and coal
mining regions and pose serious environmental hazards.
A) Carbonic acid; slag
B) Nitric acid; coal dust
C) Hydrochloric acid; bicarbonate
D) Sulfuric acid; iron oxide
11) During hydrolysis, ________ commonly decomposes into clay minerals, silica, and soluble
constituents.
A) Feldspars
B) Halides
C) Ferromagnesians
D) Carbonates
12) Which of the following rocks will be most resistant to weathering?
A) Solid bedrock
B) Jointed bedrock
C) Bedrock with solution weathering
D) Bedrock with sheeting
13) Which climate contains the optimum environment for chemical weathering?
A) Cold and dry
B) Warm and dry
C) Cold and wet
D) Warm and wet
14) ________ weathering occurs when differences in resistance or environmental factors
produce uneven surfaces on rocks.
A) Chemical
B) Differential
C) Spheroidal
D) Mechanical
15) ________ is the upper few feet of regolith that contains minerals and organic matter, water,
and air and is capable of sustaining life.
A) Horizon
B) Humus
C) Soil
D) Sediment
16) ________ is a common boundary where different parts of a system interact.
A) Sphere
B) Interface
C) Delineation
D) Geosphere
17) Soil develops in response to interactions between which Earth spheres?
A) Hydrosphere and Atmosphere
B) Geosphere, Atmosphere, and Biosphere
C) Geosphere, Hydrosphere, and Atmosphere
D) Biosphere, Atmosphere, Geosphere, and Hydrosphere
18) Which of the following components of soil is usually in the greatest percentage?
A) Mineral portion
B) Pores filled with water
C) Organic portion
D) Pores filled with air
19) ________ is decayed remains of plant and animal life.
A) Regolith
B) Hummus
C) Amino Acids
D) Humus
20) ________ is a soil that has bedrock as its parent material.
A) Humus
B) Residual soil
C) Regolith
D) Transported soil
21) ________ is a soil that has unconsolidated sediment as its parent material.
A) Humus
B) Residual soil
C) Regolith
D) Transported soil
22) ________ is the primary source of organic matter in soils.
A) Earthworms
B) Microorganisms
C) Plants
D) Animals
23) What is the definition of eluviation?
A) Decayed organic material
B) Accumulation of fine clay particles
C) Transportation of fine clay particles
D) The collective term for the O, A, E, and B horizons
24) Which horizons make up the solum?
A) C Horizon
B) O and A Horizons
C) E, B, and C Horizons
D) O, A, E, and B Horizons
25) Which horizons make up the topsoil?
A) C Horizon
B) O and A Horizons
C) E, B, and C Horizons
D) O, A, E, and B Horizons
6.2 True/False Questions
1) Weathering is the transportation or removal of broken-down materials.
2) Chemical weathering will break down a rock by changing the molecular compounds that
make-up of the rock.
3) Water expands when it freezes.
4) As roots grow, the chemicals produced at the root tips can promote cementation, making the
rocks stronger.
5) The organic acids produced when organisms decay can chemically weather rocks.
6) Before oxidation can occur with iron in olivine, the iron must be freed via hydrolysis.
7) Soils can be eroded from distant sources and deposited in new locations.
8) A soil’s parent material consists of weathered mineral matter.
9) Parent material is the primary factor that causes differences among soils.
10) The longer a soil has been forming, the thinner it becomes and the less it resembles the
parent material.
11) Fine-grained particles or iron oxide account for red, yellow, and brown colors in soil
horizons.
12) The horizon that demonstrates the greatest degree of weathering is the B horizon.
13) A vertical succession of soil horizons is called a soil profile.
14) Mature soils are characteristic of steep slopes.
15) Soil is a nonrenewable resource.
6.3 Short Answer Questions
1) Mt. Rushmore National Memorial was created at the height of the Great Depression in the
1930s by using explosives and jackhammers to sculpt granitic igneous rock. Which category of
weathering (Mechanical or Chemical) best describes how the rock was broken down? Explain
why you believe this is so.
2) Why would a pile of gravel weather faster than a single solid boulder?
Use this scenario for the following questions.
A stonemason has shaped a block of marble into a perfect cube with dimensions of 2 ft. × 2 ft. ×
2 ft.
3) What is the surface area of the cube?
4) An order has arrived that the original cube must be broken down into multiple pieces or
marble, all of the same dimension of 6 ft2 per cube. What is the total surface area of the marble
now? (Hint: Think of how many blocks the original marble cube has been broken into.)
5) Thermal expansion and thermal contraction are two processes where the presence of heat will
weather a rock. Thermal expansion occurs when the exterior of the rock is heated more quickly
than the interior and shatters. Thermal contraction occurs when the exterior of a rock cools more
quickly than the interior and splits. Into which category of weathering would you expect to find
thermal expansion and contraction? Why?
6) What role will joints in rock perform in weathering?
7) Justify why or why not hydration should be listed as a chemical weathering process.
8) A cemetery in New England contains headstones from the 17th to 21st centuries. Headstones
from the 17th century are made of slate. Headstones from the mid-19th century are made of
marble. Which headstone is going to be more legible (and therefore more resistant) and why?
9) What are the five parts of the Jenny Soil Equation?
10) Time is an important component in the soil formation process. Explain how dominant soil
formation characteristic influencing the soil will change as weathering continues over a longer
period of time.
11) How does slope orientation affect soil development?
6.4 Matching Questions
Match the mechanical weathering process with the correct definition.
A) Reduction of pressure on a pluton results in concentric layers breaking off
B) Mineral crystal development forces a rock apart
C) Expansion of ice forces a rock apart
D) Living materials break down a rock
1) Frost wedging
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 6.2 – Mechanical Weathering
Focus/Concepts: 6.2
Earth Science LO: 4.1 – Earth’s geosphere changes through geological, hydrological, physical,
chemical, and biological processes that are explained by universal laws.
2) Salt crystal growth
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 6.2 – Mechanical Weathering
Focus/Concepts: 6.2
Earth Science LO: 4.1 – Earth’s geosphere changes through geological, hydrological, physical,
chemical, and biological processes that are explained by universal laws.
3) Sheeting
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 6.2 – Mechanical Weathering
Focus/Concepts: 6.2
Earth Science LO: 4.1 – Earth’s geosphere changes through geological, hydrological, physical,
chemical, and biological processes that are explained by universal laws.
4) Biological Activity
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 6.2 – Mechanical Weathering
Focus/Concepts: 6.2
Earth Science LO: 4.1 – Earth’s geosphere changes through geological, hydrological, physical,
chemical, and biological processes that are explained by universal laws.