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Calving Ice
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Glacial erosion
Glaciers erode and transport sediment
Abrasion
Plucking
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Glacial erosion
Glacial abrasion
Rocks within the ice act like sandpaper to smooth and polish
the surface below
Rock flour (pulverized rock)
Glacial striations (grooves in the bedrock)
Glacial polish
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Glacial Striations
Striations
Glacial polish
Abrasion and Plucking,
Yosemite National Park, CA
Fig. 12.20, p. 343
Glacial deposits
Glacial drift – nonstratified, nonsorted drift deposited directly from
glacier ice
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Glacial Deposits
erratic _ a glacially_transported rock fragment different from the surface upon which it
lies.
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Glacial drift
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Till – material that is deposited directly by the ice
Outwash – materials deposited by meltwater streams coming off a glacier
Glacial till is typically unstratified and unsorted
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Glacial till
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Glacial deposits: Landforms made of till
Fig. 12.21, p. 344
moraine _ an accumulation of drift built up chiefly by the direct action of
ice.
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Glacial deposits: Moraines
DEF.: end moraine _ a ridge of drift that marks a point in the advance or recession of a glacier.
DEF.: terminal end moraine _ the end moraine marking the farthest advance of a glacier.
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Glacial deposits: alpine
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Lateral moraine
Lateral moraines
Lateral moraines
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Glacial deposits: alpine
Medial moraines
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Medial and Lateral Moraines
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Glacial deposits
Medial moraines
Ground moraine
Fig. 12.27, pp. 348-349
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Long Island is made up of end moraines
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Glacial deposits
Fig. 12.26, p. 347
Landforms made of till
Drumlins
• Smooth, elongated, parallel hills
• Steep side faces the direction from which the ice advanced
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A drumlin, upstate New York
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Drumlins,
Fig. 12.28,
p. 350
Drumlin field
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Glacial deposits
Ice Thrust Masses
Ice plucks a LARGE piece of bedrock
Hill and neighboring depression
• Devil’s Lake (Sully’s Hill to the South)
• Sibley Buttes of Kidder County
• Region of Anamoose
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Glacial deposits
Landforms made of stratified drift:
Outwash plains
Often pockmarked with depressions called kettles
Fig. 12.27
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Glacial deposits
Diagram of how kettles are formed
Glacial deposits
Def.: Kettle – a closed depression in a deposit of drift, formed when a
block of ice is buried and later melted
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Glacial deposits
Landforms made of stratified drift:
Ice-contact deposits
Deposited by meltwater flowing over, within, and at the base of
motionless ice
Include:
2
• Kames
• Eskers
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Glacial deposits
Diagram of how eskers are formed
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Glacial deposits
Def: Esker – a sinuous ridge of stratified sand and gravel formed by
subglacial stream action
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Glacial deposits
Diagram of how kames are formed
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Glacial deposits
Def.: Kame – a body of stratified drift shaped as a short, steep-sided knoll or
hummock
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Glacial Erratics
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Erosional features of glaciated valleys
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Hanging
valley
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Hanging Valley
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Pater Noster
lakes
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Pater Noster lakes
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Fig. 12.13, p. 339
U-Shaped, V-shaped, and Hanging Valleys
Fig. 12.13, p. 339
Cirques, Arêtes, and Horns
Alpine View
Cirque
Arête wall
Fig. 12.13, p. 339
Pater Noster Lakes and Tarns
Fiord
Fiord
The Matterhorn
The Matterhorn
3