Erosion%20and%20Deposition%20by%20Glaciers - PowerPoint PPT Presentation

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Erosion and Deposition by Glaciers * What are Glaciers? Glaciers are: any large mass of ice that moves slowly over land * How do Glaciers form? – PowerPoint PPT presentation

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Title: Erosion%20and%20Deposition%20by%20Glaciers

Erosion and Deposition by Glaciers
What are Glaciers?
  • Glaciers are
  • any large mass of ice that moves slowly over land

How do Glaciers form?
  • Glaciers form
  • In areas where more snow falls than melts.

What are the 2 types of glaciers?
  • Continental Glaciers
  • Valley Glaciers

Continental Valley Glaciers
  • Large masses of ice
  • Move slowly on land
  • Shape the land

Continental Glaciers
  • Description
  • a glacier that covers much of a continent
  • Feature
  • Continental glaciers can spread out over
    millions of square kilometers.
  • Location Today
  • Cover approximately 10 of Earths surface
    mainly in Greenland and Antarctica.
  • Past
  • Ice Ages when large parts of Earth were
    covered with Continental glaciers

How do Continental Glaciers move?
  • Continental Glaciers
  • can flow in all directions. They spread out
    much as pancake batter spreads out in a frying

Valley Glaciers
  • Description
  • a long narrow glacier that forms when snow and
    ice builds up in a mountain valley.
  • Feature
  • Although much smaller than continental glaciers,
    valley glaciers can be tens of kilometers long.
  • Location Today
  • High up in many mountain ranges worldwide.
  • Past
  • U-shape valleys show where Valley glaciers once
    slid down from a mountain.

How do Valley Glaciers move?
  • Valley Glaciers
  • move due to the force of gravity.

How do Glaciers Cause Erosion?
  • The two processes by which glaciers erode the
    land are
  • Plucking
  • Abrasion

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

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

Earths Surface Textbook Reference
  • Your Earths Surface textbook has a very nice
    diagram of landforms created by glacial erosion
    and deposition.
  • Please open your textbook to pages 84-85 as you
    view the next slides.

What Landforms are Created by Glacial Erosion?
  • Horn
  • When glaciers carve away the sides of a mountain,
    the result is a horn or a sharpened peak.
  • Cirque
  • A cirque is a bowl-shaped hollow eroded by a
  • Fiord
  • A fiord forms when the level of the sea rises
    filling a valley once cut by a glacier.
  • ArĂȘte
  • An arĂȘte is a sharp ridge separating two cirques.
  • U-Shaped Valley
  • Slowly moving valley glaciers carve or scoop out
    a U-shaped valley.

Glacial Deposits
  • Glacial Till
  • The sediment deposited as a glacier melts and
    recedes is known as glacial till.
  • Glacial till is of various sizes, and can be in
    the size of clay, silt, sand, gravel, or boulders.

What Landforms are Created by Glacial Deposition?
  • Moraine
  • A moraine forms at the edge of a glacier where
    the glacier deposits till. Moraines are usually
    in the form of a mound or ridge.
  • Drumlin
  • A drumlin is a long mound of till that is
    smoothed in the direction of the glaciers flow.
  • Kettle Lake
  • A kettle lake forms when a depression left in
    till by melting ice fills with water.

Glacier Picture Gallery
  • Please open the link below and go through the
    slides showing many of the landforms created by
    glacial erosion and deposition discussed in this
    power point.
  • Visual Glossary of Glacial Features

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