Weathering and Soil Formation

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CHAPTER
NEW CHAPTER
Weathering and Soil Formation
Natural forces break rocks apart and form soil,
which supports life.
4.1
Mechanical and chemical forces break down rocks.
4.2
Weathering and organic processes form soil.
4.3
Human activities affect soil.
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4.1
Mechanical and chemical forces break down rocks.
weathering
mechanical weathering
exfoliation
Over time, mechanical weathering breaks a rock
into smaller pieces.
abrasion
chemical weathering
SECTION OUTLINE
3
4.1
Mechanical and chemical forces break down rocks.
weathering
mechanical weathering
exfoliation
abrasion
Chemical weathering affects exposed rock surfaces
chemical weathering
SECTION OUTLINE
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weathering
4.1
Mechanical and chemical forces break down rocks.
weathering
mechanical weathering
The process by which natural forces break down
rocks.
exfoliation
abrasion
chemical weathering
KEY CONCEPT SUMMARY
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mechanical weathering
4.1
Mechanical and chemical forces break down rocks.
weathering
mechanical weathering
The breakdown of rock into smaller pieces of the
same material without any change in its
composition.
exfoliation
abrasion
chemical weathering
KEY CONCEPT SUMMARY
6
exfoliation
4.1
Mechanical and chemical forces break down rocks.
weathering
mechanical weathering
In geology, the process in which layers or sheets
of rock gradually break off.
exfoliation
abrasion
chemical weathering
KEY CONCEPT SUMMARY
7
abrasion
4.1
Mechanical and chemical forces break down rocks.
weathering
mechanical weathering
The process of wearing something down by friction.
exfoliation
abrasion
chemical weathering
KEY CONCEPT SUMMARY
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chemical weathering
4.1
Mechanical and chemical forces break down rocks.
weathering
mechanical weathering
The breakdown or decomposition of rock that takes
place when minerals change through chemical
processes.
exfoliation
abrasion
chemical weathering
KEY CONCEPT SUMMARY
9
Weathering and organic processes form soil.
4.2
humus
Soil has measurable properties, such as color,
texture, pore space, and chemistry.
soil horizon
soil profile
Soil is a mixture of weathered rock, organic
matter, water, and air.
Plants, microorganisms, and animals affect soil
characteristics.
SECTION OUTLINE
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humus
4.2
Weathering and organic processes form soil.
humus
soil horizon
soil profile
The decayed organic matter in soil.
KEY CONCEPT SUMMARY
11
soil horizon
4.2
Weathering and organic processes form soil.
humus
soil horizon
soil profile
A soil layer with physical and chemical
properties that differ from those of soil layers
above or below it.
KEY CONCEPT SUMMARY
12
soil profile
4.2
Weathering and organic processes form soil.
humus
soil horizon
soil profile
The soil horizons in a specific location a cross
section of soil layers that displays all soil
horizons.
KEY CONCEPT SUMMARY
13
Human activities affect soil.
4.3
Soil is essential to life and takes a long time
to form. It is difficult or impossible to replace
soil that has been lost.
desertification
SECTION OUTLINE
14
Human activities affect soil.
4.3
Soil is essential to life and takes a long time
to form. It is difficult or impossible to replace
soil that has been lost.
desertification
SECTION OUTLINE
15
desertification
4.3
Human activities affect soil.
desertification
The expansion of desert conditions in areas where
the natural plant cover has been destroyed.
KEY CONCEPT SUMMARY
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4.1
Mechanical and chemical forces break down rocks.
I. Mechanical and chemical forces break down
rocks.
weathering
A. Weathering breaks rocks into smaller pieces.
mechanical weathering
B. Mechanical weathering produces physical
changes in rocks.
exfoliation
abrasion
C. Chemical weathering changes the mineral
composition of rocks.
chemical weathering
1. Dissolving
2. Rusting
D. Weathering occurs at different rates.
KEY CONCEPT SUMMARY
17
Weathering and organic processes form soil.
4.2
II. Weathering and organic processes form soil.
humus
A. Soil is a mixture of weathered rock particles
and other materials.
soil horizon
1. Soil Composition
soil profile
2. Soil Horizons
B. Climate and landforms affect soil.
C. The activities of organisms affect soil.
D. Properties of soil can be observed and
measured.
1. Texture
2. Color
3. Pore Space
4. Chemistry
KEY CONCEPT SUMMARY
18
Human activities affect soil.
4.3
III. Human activities affect soil.
desertification
A. Soil is a necessary resource.
B. Land-use practices can harm soil.
1. Farming
2. Construction and Development
3. Mining
C. Soil can be protected and conserved.
KEY CONCEPT SUMMARY