glacial processes and landforms P1

• Through what processes do glaciers shape the land?

  Erosion, transportation, weathering, and deposition
• What are the two main types of glacial erosion?

  Abrasion and plucking
• What is abrasion in the context of glacial erosion?

  Rocks frozen in the glacier scrape the bedrock
• What are striations?

  Scratches left by abrasion on bedrock
• How does plucking erode the landscape?

  Rocks freeze to the glacier and are pulled away
• What is the main type of weathering in glacial environments?

  Freeze thaw weathering
• By what percentage does water expand when it freezes?

  About nine percent
• How does freeze-thaw weathering enlarge cracks in rocks?

  Water expands when it freezes, widening cracks
• What is a corrie?

  An armchair shaped hollow on a mountain
• What are corries called in France?

  Cirques
• What are corries called in Wales?


  Swims
• Where do corries typically form in the Northern Hemisphere?

  North facing slopes
• How does snow turn into ice in a corrie?

  It compacts and air is squeezed out
• How is the back wall of a corrie steepened?

  Freeze thaw weathering and plucking
• How does the base of the corrie become deeper?

  Abrasion
• What is rotational slip?

  Circular motion of a glacier in a corrie
• What is a corrie lip?

  The raised front of a corrie
• What is a tarn?

  A lake in a corrie
• What are arêtes?

  Narrow ridges between two corries
• What are pyramidal peaks?

  Pointed peaks formed by multiple corries
• How does a glacier erode a river valley?

  Through abrasion and plucking
• Why do glaciers follow old river valleys?

  They are the path of least resistance
• What are truncated spurs?

  Eroded ends of interlocking spurs
• What is a U-shaped glacial trough?

  A valley carved by a glacier
• What is a ribbon lake?

  A glacial trough filled with water
• What are hanging valleys?

  Suspended old tributaries
• What is a moraine?

  Material carried or moved by a glacier
• Where is lateral moraine deposited?

  Along both sides of the glacier
• Where is medial moraine deposited?

  In the middle of the glacier
• Where is terminal moraine deposited?

  At the end of a glacier
• What is glacial till also called?

  Boulder clay
• What are glacial erratics?

  Rocks deposited from a different area
• Why are erratics called 'erratic'?

  Because they are out of place
• What are drumlins?

  Mounds of deposited moraine
• What does "basket of eggs topography" describe?

  A landscape with many drumlins
• What is glacial drift?

  Material moved by glacial meltwater
• What is glacial outwash?

  Sand and gravel deposited by meltwater
• Where are heavier particles of sand and gravel deposited?

  In the glaciated valley
• Where are lighter particles such as clay deposited?

  In the outwash plain
• How does freeze-thaw weathering work?

  • Water enters cracks in rocks.
  • Temperature drops below freezing (0°C).
  • Water freezes and expands by about 9%.
  • Cracks enlarge with repeated thawing and freezing.
  • Pieces of rock break off over time.