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Glaciers Carve Land and Move Sediments

Section 5.4

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Explore Glaciers pg 165

• What happened when the ice cube was dragged across the clay?

• What happened to the sand and gravel in the ice cube as it melted?

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Extent of Glaciers

• Glaciers are– In mountain ranges around the world– In land regions at North Pole and South Pole– 10% of Earth’s surface TODAY– Used to be 30% 30,000 years ago

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2 Types of Glaciers

• Alpine Glaciers• Called valley glaciers• Can cause a V

shaped mountain valley to become a U shaped valley

• If an alpine glaciers flows into an ocean, blocks can break off and form an iceberg!

• Continental Glaciers• Called ice sheets• Cover Greenland• Cover Antarctica

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2 Types of Glaciers..continued

• Where do each of the two types of glaciers form?

• Alpine glaciers form in mountains and flow into valleys.

• Continental glaciers form on large landmasses (continents) near the poles (North/South).

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Glacier= large mass of ice that moves over land

• Alpine Glacier…what are the dark lines?

• These are rocks picked up by the glacier along its route.

Continental Glacier

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Why are the cracks shown near the surface of the glacier and not at the

bottom?• At the bottom….

The ice is under somuch pressure thatit flows instead ofcracking….not asmuch pressureon the top so itcracks.

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How is an alpine glacier like a plow?

• The glacier– Scoops up rock and soil– Picks rocks from the sides of valleys– Sediment moves with it

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What’s left behind?

• Till= the sediment left on the ground by a retreating glacier.

• Moraine= a deposit or hill of till

• AND……..Moraine at Mono Lake, California, United States

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What’s left behind?

• Kettle Lakes= bowl depression that was once filled in with ice that has melted after the glacier retreated.

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Section Review page 170

• 1. List 2 processes that cause glaciers to move.– Gravity– Water making the bottom slippery will cause

flowing and sliding

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Section Review page 170

• 2. What are the two major types of glaciers and where are they found?– Alpine and found in mountain valleys– Continental and found in Antarctica and

Greenland

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Section Review page 170

• 3. Describe the land features left behind by glaciers that have melted and shrunk.

– Glaciers leave• U-shaped valleys• Moraines• Abrasions• Till• Kettle lakes

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Section Review page 170

• 4. Identify two ways in which the erosion effects of glaciers differ from those of rivers.– a. Glaciers crush and move large rocks

• Rivers move smaller sediments

– b. Glaciers pile up moraines, etc• Rivers create sandbars, meanders, and deltas

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Section Review page 170

• 5. How would glaciers be affected by changes in climate, such as global warming and global cooling?

• Warming melts glaciers and shrinks ice sheets (continental glaciers)

• Cooling causes glaciers to expand and form in new places.

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Section Review page 170

• 6. Regions near the equator are generally the warmest on Earth. However, in one small area of Africa, there are glaciers close to the equator. Form a hypothesis to explain why these glaciers exist.16

• IF there are glaciers in Africa near the equator, • THEN they are in the high mountains • BECAUSE high mountains could be cold

enough for glaciers.