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SUMMARY

Weathering is the breaking up, crumbling, and destruction of any kind of 3. Muddy water rushing downstream after a heavy rain is an
solid rock. The process of physically picking up weathered rock materials example of
is called erosion. After the eroded materials are picked up, they are re- a. weathering.
b. washing.
moved by transportation agents. The combined action of weathering,
c. erosion.
erosion, and transportation wears away and lowers the surface of Earth.
d. transportation.
The physical breaking up of rocks is called mechanical weather-
4. The physical breakup of rocks without any changes in their
ing. Mechanical weathering occurs by wedging effects and the effects
chemical composition is
of reduced pressure. Frost wedging is a wedging effect that occurs from
a. oxidation.
repeated cycles of water freezing and thawing. The process of spalling
b. mechanical weathering.
off of curved layers of rock from reduced pressure is called exfoliation.
c. erosion.
The breakdown of minerals by chemical reactions is called chemical d. transportation.
weathering. Examples include oxidation, a reaction between oxygen and
5. Chemical weathering, the dissolving or breaking down of
the minerals making up rocks; carbonation, a reaction between carbonic minerals in rocks, is also called
acid (carbon dioxide dissolved in water) and minerals making up rocks; a. oxidation.
and hydration, the dissolving or combining of a mineral with water. Gran- b. reduction.
ite is composed of feldspars, quartz, and some ferromagnesian minerals. c. disintegration.
The end products of complete mechanical and chemical weathering of d. decomposition.
granite are quartz sand, clay minerals, metal oxides, and soluble salts. 6. The process of peeling off layers of rock, reducing the pressure
Soil is a mixture of weathered earth materials and humus. When the on the rock’s surface, is called
end products of complete weathering of rocks are removed directly by a. chemical peel.
b. exfoliation.
gravity, the erosion is called mass movement. Landslide is a generic term
c. wedging.
meaning any type of movement by any type of material. Erosion and trans-
d. disintegration.
portation also occur through the agents of running water, glaciers, or wind.
7. The weak acid formed by the reaction of water with carbon dioxide is
Each creates its own characteristic features of erosion and deposition.
a. carbonic acid.
b. carbonate acid.
KEY TERMS c. hydrocarbonic acid.
d. dihydrocarbonate acid.
8. A mixture of unconsolidated weathered earth materials and humus is
delta (p. 510)
a. gravel.
dune (p. 513)
b. soil.
erosion (p. 502)
c. dirt.
floodplain (p. 509)
d. mud.
glacier (p. 510)
9. Decay-resistant, altered organic material is
landforms (p. 514)
a. soil.
mass movement (p. 507) b. clay.
soil (p. 506) c. topsoil.
weathering (p. 502) d. humus.
10. Two minerals that usually remain after granite has completely
weathered are
APPLYING THE CONCEPTS a. quartz and clay.
b. quartz and hematite.
1. Small changes that result in the breaking up, crumbling, and c. olivine and granite.
destruction of any kind of rock are d. quartz and basalt.
a. decomposition. 11. Weathered materials move to lower elevations due to only
b. weathering. a. wind.
c. corrosion. b. rain.
d. erosion. c. gravity.
2. The process of physically removing weathered materials is called d. erosion.
a. weathering. 12. The slow movement downhill of soil on the side of a mountain is
b. transportation. called
c. erosion. a. rockslide.
d. corrosion. b. avalanche.
c. creep.
d. crawl.

516 CHAPTER 20 Shaping Earth’s Surface 20-16