Chapter 08 - Erosion and Deposition.pdf - Erosion and...

Erosion and Deposition
Chapter 8 p. 244-283

Changing Earth’s
Surface
Lesson 8-1

By the end of the lesson, I will be
able to…

Describe the processes that
wear down and build up Earth’s
surface.

Identify the force that pulls rock
and soil down slopes.

I. Wearing Down and Building Up
A.
Erosion is the process by which natural
forces move weathered rock and soil
from one place to another.
B.
The material moved by erosion is
sediment .
C.
Deposition occurs where the agents of
erosion lay down sediment.
D.
Weathering, erosion, and deposition act
together in a cycle that wears down and
builds up Earth’s surface.

II. Mass Movement
A.
Gravity is the force that moves rock and
other materials downhill.
B.
Gravity, running water, glaciers, waves,
and wind cause erosion.
C.
Gravity causes mass movement , any
one of several processes that move
sediment downhill.
D.
The different types of mass movement
include landslides, mudslides, slump,
and creep.

II. Mechanical Weathering
D.
The most destructive kind of mass
movements is a landslide, which occurs
when rock and soil slide quickly down a
steep slope.

II. Mechanical Weathering
E.
A mudflow is the rapid downhill
movement of a mixture of water, rock,
and soil.
F.
Mudflows often occur after heavy rains
in a normally dry area.

II. Mechanical Weathering
G.
In slump, a mass of rock and soil
suddenly slips down a slope.
H.
The material in slump moves down in
one large mass.

II. Mechanical Weathering
I.
Creep is the very slow downhill
movement of rock and soil, even
occurring on gentle slopes.
J.
Creep often results from the freezing
and thawing of water in cracked layers
of rock beneath the soil.

In-Class Review
1.
Explain the difference between erosion
and deposition.
2.
What forces cause erosion?
3.
What are four types of mass
movement?
4.
Why would a landslide be more likely on
a steep mountain than on a gently
sloping hill?

Assignment

Read pages 252-261

Water Erosion
Lesson 8-2

By the end of the lesson, I will be
able to…

Explain how water erosion is mainly
responsible for shaping Earth’s land
surface.

Describe some of the land features
formed by water erosion, including
groundwater erosion.

Describe land features formed when
rivers and streams deposit sediment.

Describe the features of a river
system.

I. Runoff and Erosion
A.
Moving water is the major agent of the erosion
that has shaped Earth’s land surface.
B.
Runoff is all the remaining water that moves
over Earth’s surface.
C.
As runoff travels, it forms tiny grooves in the
soil called rills .
D.
A gully is a large
groove, or channel, in
the soil that carries
runoff after a
rainstorm.

I. Runoff and Erosion
E.
A stream is a channel along which water is
continually flowing down a slope.
F.
As streams flow together, they form larger and
larger bodies of flowing water.