Chapter 3 Erosion and Deposition Chapter Preview 3.1 Changing Earth’s Surface 3.2 Water Erosion...

Chapter 3 Erosion and Deposition

Chapter Preview

3.1 Changing Earth’s Surface

3.2 Water Erosion

3.3 Waves and Wind

3.4 Glaciers

Table of Contents


Chapter Preview Questions

1. The process that breaks down rock and other substances at Earth’s surface is called

a. uniformitarianism.

b. weathering.

c. mountain building.

d. erosion.



2. What is the term for the mixture of rock particles, minerals,

decayed organic material, water, and air?

a. bedrock

b. humus

c. loam

d. soil



3. Which of the following is a cause of mechanical weathering?

a. abrasion

b. oxygen

c. acid rain

d. living organisms



4. Conservation plowing, crop rotation, and contour plowing are methods of promoting

a. soil loss.

b. soil conservation.

c. loss of fertility.

d. loss of topsoil.


Suppose that you fill a jar halfway with layers of gravel, sand, and soil. Then you fill the jar with water, cover it tightly, and shake for 5 seconds. What effect would shaking the jar have on the soil, sand, and gravel? What would happen to them after the shaking stops? Explain your answer.

What are the forces of erosion and deposition that

shape our landscape?


Latin Word Origins

Word Meaning Examples

From, down, away Deflation, depositionde-


Latin Word Origins


Blow Deflationflare


Latin Word Origins


-mentum The act of, the result of Movement


Latin Word Origins


positus Put Deposition


Latin Word Origins


Sit, settle Sedimentsedere


Apply It!

Review the Latin words and meanings. Look at the word sedere

and the second meaning of mentum. Predict the meaning of

sediment. Revise your definition as you read the chapter.

Sample: Sedere means “settle” and mentum means “the result of.”


End of Chapter Preview


Section 1:Changing Earth’s Surface

What processes wear down and build up Earth’s surface?

What causes the different types of mass movement?


Wearing Down and Building Up

Weathering, erosion, and deposition act together in a cycle that wears down and builds up Earth’s surface.


Mass Movement

The different types of mass movement include landslides, mudflows, slump, and creep.


Mass Movement Activity

Click the Active Art button to open a browser window and access Active Art about mass movement.


End of Section:Changing Earth’s

Surface


Section 2:Water Erosion

What process is mainly responsible for shaping the surface of the land?

What features are formed by water erosion and deposition?

What factors affect a river’s ability to erode and carry sediment?


Sediment in Motion

Streams carry sediment in several ways.


Runoff and ErosionPrecipitation over the United States averages about 75 cm per year. About 22.5 cm becomes runoff. Generally, more runoff means more erosion.


Runoff and Erosion

Water flowing across the land runs together to form rills, gullies, and streams.


Erosion by Rivers

A waterfall forms where a flat layer of tough rock lies over a layer of softer rock that erodes easily. When the softer rock erodes, pieces of the harder rock above break off, creating the waterfall’s sharp drop.


Erosion by Rivers

Erosion often forms meanders and oxbow lakes where a river winds across its floodplain.


Deposits by Rivers

Deposition creates landforms such as alluvial fans and deltas.


The Course of a River

The slope and size of a river, as well as the sediment it carries, determine how a river shapes the land.


Erosion and Sediment Load

A river’s slope is usually greatest near the river’s source. As a river approaches its mouth, its slope lessens.


Sediment on the Move

The speed, or velocity, of a stream affects the size of the sediment particles the stream can carry. Study the graph, then answer the following questions.



Stream velocity

Reading Graphs:

What variable is shown on

the x-axis of the graph?



Diameter of sediment particles

Reading Graphs:

What variable is shown on the y-axis of the graph?



About 50 cm/sec; about 90 cm/sec; about 800 cm/sec

Interpreting Data:

What is the speed at which a stream can move coarse sand? Small pebbles? Large boulders?



Small boulders

Predicting:

A stream’s speed increases to about 600 cm per second during a flood. What are the largest particles the stream can move?



The faster the speed of the flowing water, the larger the particles the stream is able to move.

Developing Hypotheses:

Write a hypothesis that states the relationship between the speed of a stream and the size of sediment particles it can move.


Erosion and Sediment Load

A river erodes sediment from its banks on the outside curve and deposits sediment on the inside curve.


More on Floods

Click the Planet Diary button for an activity about floods.


End of Section:Water Erosion


Section 3:Waves and WindWhat gives waves their energy?

How do waves shape a coast?

What are the causes and effects of wind erosion?


Erosion by Waves

Waves shape the coast through erosion by breaking down rock and transporting sand and other sediment.


Erosion by Waves

Erosion and deposition create a variety of features along a coast.


Deposits by Waves

Waves shape a coast when they deposit sediment, forming coastal features such as beaches, spits, and barrier beaches.


How Wind Causes Erosion

Wind erosion moves sediment particles of different sizes in the three ways shown below.


Wind Deposition

Wind erosion and deposition may form sand dunes and loess deposits.


Links on Waves

Click the SciLinks button for links on waves.


Waves

Click the Video button to watch a movie about waves.


End of Section:Waves and Wind


Section 4:Glaciers

What are the two kinds of glaciers?

How does a valley glacier form and move?

How do glaciers cause erosion and deposition?


How Glaciers Form and Move

During the last ice age, a continental glacier covered most of northern North America.


How Glaciers Shape the Land

As a glacier moves, plucking breaks pieces of bedrock from the ground.



Erosion by glaciers can carve a mountain peak into a sharp horn and grind out a V-shaped valley to form a U-shaped valley.



As glaciers advance and retreat, they sculpt the landscape by erosion and deposition.


Links on Glaciers

Click the SciLinks button for links on glaciers.


End of Section:Glaciers


QuickTake Quiz

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Chapter 3 Erosion and Deposition Chapter Preview 3.1 Changing Earth’s Surface 3.2 Water Erosion...

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