Erosion and Erosion and Deposition by Deposition by

GlaciersGlaciers

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What are Glaciers?What are Glaciers?

Glaciers are:any large mass of ice that moves slowly over

land

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How do Glaciers form?How do Glaciers form?

Glaciers form:Glaciers form:

In areas where more In areas where more snow falls than melts.snow falls than melts.

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What are the 2 types of What are the 2 types of glaciers?glaciers?

Continental GlaciersContinental Glaciers Valley GlaciersValley Glaciers

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Continental & Valley GlaciersContinental & Valley Glaciers

Large masses of iceLarge masses of ice Move slowly on landMove slowly on land

Shape the landShape the land

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Continental GlaciersContinental GlaciersDescription:Description:

a a glacier that covers much of a continent

Feature:Feature:

Continental glaciers can spread out over Continental glaciers can spread out over millions of square kilometers.millions of square kilometers.

Location Today:Location Today:Cover approximately 10% of Earth’s surface mainly in Greenland and Antarctica.

Past:Past:

Ice Ages – when large parts of Earth were Ice Ages – when large parts of Earth were covered with Continental glacierscovered with Continental glaciers

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How do Continental How do Continental Glaciers move?Glaciers move?

Continental Glaciers:Continental Glaciers:• can flow in all directions. They spread can flow in all directions. They spread

out much as pancake batter spreads out out much as pancake batter spreads out in a frying pan.in a frying pan.

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Valley GlaciersValley GlaciersDescription:Description:

a long narrow glacier that forms when snow and ice builds up in a mountain valley.

Feature:Feature:

Although much smaller than continental Although much smaller than continental glaciers, valley glaciers can be tens of glaciers, valley glaciers can be tens of kilometers long.kilometers long.

Location Today:Location Today:High up in many mountain ranges worldwide.

PastPast: :

U-shape valleys show where Valley glaciers U-shape valleys show where Valley glaciers once slid down from a mountain.once slid down from a mountain. 88

How do Valley Glaciers move?How do Valley Glaciers move?

Valley Glaciers:Valley Glaciers:• move due to the force of gravitymove due to the force of gravity..

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How do Glaciers Cause How do Glaciers Cause Erosion?Erosion?

The two processes by which glaciers The two processes by which glaciers erode the land are:erode the land are:• PluckingPlucking• AbrasionAbrasion

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PluckingPlucking

Plucking is:Plucking is:

The process by which The process by which a glacier picks up rocks a glacier picks up rocks as it flows across the as it flows across the land. land.

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AbrasionAbrasionAbrasion occurs:Abrasion occurs:

• As a glacier drags the As a glacier drags the rock over the ground the rock over the ground the land is gouged & land is gouged & scratched.scratched.

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Earth’s Surface Textbook Earth’s Surface Textbook ReferenceReference

Your Earth’s Surface textbook has a Your Earth’s Surface textbook has a very nice diagram of landforms very nice diagram of landforms created by glacial erosion and created by glacial erosion and deposition.deposition.

Please open your textbook to pages Please open your textbook to pages 84-85 as you view the next slides.84-85 as you view the next slides.

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What Landforms are Created by What Landforms are Created by Glacial Erosion? Glacial Erosion?

Horn:Horn:• When glaciers carve away the sides of a mountain, the When glaciers carve away the sides of a mountain, the

result is a result is a hornhorn or a sharpened peak. or a sharpened peak. Cirque:Cirque:

• A A cirquecirque is a bowl-shaped hollow eroded by a glacier. is a bowl-shaped hollow eroded by a glacier. Fiord:Fiord:

• A A fiordfiord forms when the level of the sea rises filling a forms when the level of the sea rises filling a valley once cut by a glacier.valley once cut by a glacier.

Arête:Arête:• An An arêtearête is a sharp ridge separating two cirques. is a sharp ridge separating two cirques.

U-Shaped Valley:U-Shaped Valley:• Slowly moving valley glaciers carve or scoop out a U-Slowly moving valley glaciers carve or scoop out a U-

shaped valley.shaped valley. 1414

Glacial DepositsGlacial DepositsGlacial Till:Glacial Till:

• The sediment deposited as a glacier melts The sediment deposited as a glacier melts and recedes is known as glacial till. and recedes is known as glacial till.

• GGlacial tilllacial till is of various sizes, and can be in is of various sizes, and can be in the size of clay, silt, sand, gravel, or the size of clay, silt, sand, gravel, or boulders.boulders.

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What Landforms are Created by What Landforms are Created by Glacial Deposition? Glacial Deposition?

Moraine:Moraine:• A moraine forms at the edge of a glacier where the A moraine forms at the edge of a glacier where the

glacier deposits till. Moraines are usually in the form of glacier deposits till. Moraines are usually in the form of a mound or ridge.a mound or ridge.

Drumlin:Drumlin:• A drumlin is a long mound of till that is smoothed in the A drumlin is a long mound of till that is smoothed in the

direction of the glaciers flow.direction of the glaciers flow. Kettle Lake:Kettle Lake:

• A kettle lake forms when a depression left in till by A kettle lake forms when a depression left in till by melting ice fills with water.melting ice fills with water.

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Glacier Picture GalleryGlacier Picture Gallery

Please open the link below and go Please open the link below and go through the slides showing many of through the slides showing many of the landforms created by glacial the landforms created by glacial erosion and deposition discussed in erosion and deposition discussed in this power point.this power point.

Visual Glossary of Glacial Features

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Brain Pop on Glaciers and Ice Brain Pop on Glaciers and Ice AgesAges

If you would like to watch a cute If you would like to watch a cute video presented by Brain Pop to video presented by Brain Pop to learn more about Glaciers and Ice learn more about Glaciers and Ice Ages, click on the link below.Ages, click on the link below.

http://www.brainpop.com/science/earthsystem/glaciers/

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