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Erosion and Deposition
Table of Contents
Glacial Erosion
Effects of Glaciers
Ms. De Los Rios
6th Grade
Vocabulary 4.2
Glacier- Any large mass of ice that moves slowly over land.
Continental Glacier- a glacier that covers much of a continent or
large island.
Ice age- Time in Earth’s history during which glaciers covered large
parts of the surface.
Valley glacier- A long, narrow glacier that forms when snow and ice
build up in a mountain valley.
Plucking- The process by which a glacier picks up rocks as it flows
over the land.
Till- the sediments deposited directly by a glacier.
Moraine- a ridge formed by the till deposited at the edge of a glacier.
Kettle- a small depression that forms when a chunk of ice is left in
glacial till.
Continental Glaciers
large mass of ice that moves slowly over land.
How Do Glaciers Form and Move? Pg. 129
A glacier as any large mass of ice that moves slowly over land.
Glaciers can form only in an area where more snow falls than melts.
are two kinds of glaciers:
continental glaciers and valley glaciers.
Continental Glaciers
• a glacier that covers much of a continent or large island.
Continental glaciers can flow in all directions as they move.
• Many times in the past, continental glaciers have covered large parts of
Earth’s surface=These times are known as ice ages.
Glacial Erosion
Continental Glaciers
Continental glaciers can flow in all directions as they move. What are some
changes in elevation and ice depth on this chart?
Valley Glaciers
Is a long, narrow glacier that forms when snow and ice build up
high in a mountain valley.
Valley Glaciers pg. 130
Valley Glaciers how do they form??
Is a long, narrow glacier that forms when snow and ice build up high in
a mountain valley. The sides of mountains keep these glaciers from
spreading out in all directions. Instead, they usually move down
valleys that have already been cut by rivers.
Where can we find valley glaciers??
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High mountains where the temp. rarely rises above freezing.
Snow builds up every year.
The weight of snow compacts snow at the bottom into ice!
Glaciers can form only in an area where more snow falls than melts.
They are much smaller than cont. glaciers, however, they can be tens
of km. long
• Once glaciers is more than 30-40 meters deep, the glaciers begin to
move.
Gravity constantly pulls a glacier downhill.
APPLY IT!!!
Valley Glaciers
When glaciers recede, they
leave behind evidence of their
existence.
1. What was the landscape
like before glaciers formed?
2. What did the glaciers do to
the area?
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Glacial Erosion pg. 130
How Do Glaciers Cause Erosion? Pg. 131
The movement of a glacier changes the land beneath it.
The two processes by which glaciers erode the land are
plucking and abrasion.
eddd
How Can they cause Erosion??
• As a glacier flows over the land, it picks up rocks in a process
called plucking.
• Many rocks remain on the bottom of the glacier, and the glacier
drags them across the land. This process, called abrasion,
gouges and scratches the bedrock.
Glacier Deposition
When a glacier melts, it deposits the sediment it eroded from
the land, creating landforms.
Glacial till
The mixture of
sediments that a glacier
deposits directly on the
surface is called till.
Till is made up of clay,
silt, sand, gravel, and
boulders.
Glacial Deposition pg. 132
The till deposited at the edges of a glacier forms a ridge called a
moraine.
A terminal moraine is the ridge of till at the farthest point reached by
a glacier.
A kettle is a small depression that forms when a chunk of ice is left
in glacial till and later melts.
If the kettle gets filled with water, a kettle lake forms.
Other features of glacial erosion or deposition include:
horns- when glaciers carve away the sides of mountain (sharpened peak)
Arêtes- is a sharp ridge separating two cirques.
Cirques- bowl shaped hollow eroded by a glacier
U-shaped valleys- A flowing glacier scoops out a u-shaped valley.
Drumlin- Is a long mound of till that is smoothed in the direction of the
glacier’s flow.
Glacial Erosion fig. 2 pg. 131
Glacial Erosion
What type of glacial erosion does
this picture show? In which
direction is the ice moving?
1. Draw an arrow in the
diagram about to show the
direction the ice is moving.
2. In your own words,
describe the glacial erosion
taking place in the diagram.
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How Do Glaciers cause Erosion and
Deposition?
The
2 processes by glacier erode the land are:
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•What causes Glacial deposition? (pg. 132)
•Types of landforms created by glacial deposition:
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Glacial Erosion- Glacial Landforms pg. 132
Glacial Erosion pg. 133
A.Y.U.
Explain the features of Erosion, Deposition and Photo Feature.