Formation of a Corrie

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Formation of a Corrie
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Small hollow on the north facing side of a
hillside
Water enters cracks in the rock. when
temperatures fall below zero the water freezes
and expands putting huge amounts of pressure on
the surrounding rock. When temperatures rise
again the water melts releasing the pressure.
This process is known as freeze-thaw. This
weakens the surrounding rocks.
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Snow begins to collect in the hollow, and soon
turns to ice in the falling temperatures. As
snow continues to fall, the ice overflows out of
the hollow to form a glacier
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Direction of Ice Movement
The glacier freezes onto the surrounding rocks,
that have been weakened by freeze-thaw. As the
glacier moves downhill due to gravity, it tears
away these rocks. This process is known as
Plucking
GLACIER
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Huge amounts of rock are torn away from the
hillside, leaving a huge hollow.
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Rocks embedded within the glacier scrape against
the rock surface, acting like sandpaper,
smoothening the surface. This process is known
as abrasion.
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Original profile, before glaciation
After glaciation, a huge hollow in the hillside,
called a corrie
After glaciation, a small mound of moraine is
left, forming a lip
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Often meltwater remains in the corrie, known as a
tarn or corrie loch
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Formation of a U-Shaped Valley
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Before glaciation, U-Shaped valleys are V-Shaped
river valleys.
Water enters cracks in the rock. When
temperatures fall below zero the water freezes
and expands putting huge amounts of pressure on
the surrounding rock. When temperatures rise
again the water melts releasing the pressure.
This process is known as freeze-thaw. This
weakens the surrounding rocks.
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Snow and ice begin to move through the valley
floor as a glacier.
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The glacier freezes onto the surrounding rocks,
that have been weakened by freeze-thaw. As the
glacier moves downhill due to gravity, it tears
away these rocks. This process is known as
Plucking
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Huge amounts of rock are torn away from the
valley sides and base, leaving very steep sides
and a flat base.
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Rocks embedded within the glacier scrape against
the rock surface, acting like sandpaper,
smoothening the surface. This process is known
as abrasion.
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Original profile, before glaciation
After glaciation, a U-Shaped valley has been
formed, with steep side walls and a flat base.
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Name 3 similarities between the formation of a
Corrie and the formation of a U-Shaped Valley

• Freeze Thaw Action
• Plucking
• Abrasion

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Before Glaciation
During Glaciation
After Glaciation
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Task 1

• Using the information that you have just heard
  and your
• notes, answer the following question
• Select one feature of glacial erosion
• and explain the processes involved in the
• formation of this feature.
• Annotated diagrams may be used.
• 4 marks