Table of Contents

Glacial Erosion

Effects of Glaciers

Ms. De Los Rios

6th Grade

Erosion and Deposition

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.

Continental GlaciersContinental glaciers can flow in all directions as they move. What are some changes in elevation and ice depth on

this chart?

Glacial Erosion

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??

• 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.

Valley GlaciersWhen 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?____________________________________________________________________________________________________

APPLY IT!!! 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.

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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 ErosionWhat 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. _______________________________________________________________________________________________

Glacial Erosion fig. 2 pg. 131

How Do Glaciers cause Erosion and Deposition?

The 2 processes by glacier erode the land are:

• •

•What causes Glacial deposition? (pg. 132)

•Types of landforms created by glacial deposition:• • •

Glacial Erosion- Glacial Landforms pg. 132

Explain the features of Erosion, Deposition and Photo Feature.

Glacial Erosion pg. 133A.Y.U.