Erosion and Deposition by Wind, Ice and Gravity

Wind, Ice, and Gravity

by Jenny Shaw

Multiple Choice

True or False: Wind can erode the surface of the Earth.

• True

• False

​How Does Wind Shape the Earth?

​Abrasion= wearing down of a surface by rock or other particles

​

​- Leaves behind a smooth, polished surface

​

​Deflation= removal of sediment by wind

​ - Leaves behind a desert pavement (mostly pebbles and rocks that are too heavy for wind to carry

Multiple Choice

Which process is more likely to form smooth, polished rocks?

• Abrasion

• Deflation

Dunes and Loess​

• ​When wind slows down, it starts to drop it's sediment.

  • ​Dunes= mounds of sand deposited by wind.

    • ​Usually steeper on one side.

• Loess= very fine sediment that can be carried very far.​

  • ​Forms very rich soil that is good for growing crops

Multiple Choice

Why can loess be carried farther than regular sand?

• It has more nutrients.

• It is carried by a stronger wind.

• It is very light.

• It has less water in it.

Poll

True or False: Wisconsin has many landforms made by glaciers.

• True

• False

​How Does Ice Shape the Earth?

• ​Glacier= mass of moving ice formed by compacted snow

• ​Large glaciers slowly move downhill.

  • ​They pick up materials as they move, which they later drop as they melt

    • ​Glacial drift= movement of materials by glaciers

• ​They also cause scratches and abrasions on the rocks they pass.

​Types of Glaciers

• ​Alpine glacier-forms in a mountainous area.

  • Often form in a V-shaped valley.

  • ​Widen it into a U-shape.

• ​Alpine landforms:

  • ​Cirque= bowl-shaped depression

  • ​Arete= ridge between 2 cirques

  • ​Horn= 3 or more aretes joined together

Multiple Choice

An alpine glacier can turn a V-shaped valley into what shape?

• A-shaped

• U-shaped

• W-shaped

• S-shaped

Multiple Choice

What is another name for the bowl shape left behind by an alpine glacier?

• Arete

• Horn

• Cirque

• Sand dune

Multiple Choice

When you combine 3 or more aretes, you get what?

• Horn

• Cirque

• U-shaped valley

• Alpine glacier

​Continental Glaciers

• ​Form over a large, mostly flat area

• ​Flatten and smooth the land as they move

• ​Continental landforms:

  • ​Erratics= large boulders deposited by a glacier

  • ​Kettle lakes= lakes formed by chunks of ice left behind by a glacier

Multiple Choice

Which type of glacier causes flatter, less rugged landforms?

• Continental

• Alpine

Multiple Select

Which of these landforms would most likely be formed by a continental glacier? (you may select more than one)

• Arete

• Cirque

• Erratic

• Kettle lake