Glacial Features and Landforms

This is a copy of the notes I made to revise glaciers. It describes and gives examples of all of the main landforms shaped by glacial erosion, and has lots of vocab.

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  • Created by: Aoife
  • Created on: 07-01-10 17:06
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Glacial Features and Landscapes
The Antarctic landmass is covered by ice-sheets and very little of the land is visible; only the highest
peaks can be seen. Very slowly, these ice-sheets move down to lower latitude and melt. Chunks of
them break off and float out to sea.
Ice permanently covers the ground of the higher latitudes and collects in the hollows of the
mountainsides. As the ice collects over thousands of years, it is pushed down the valleys as valley
glaciers. At lower latitudes, the glaciers melt at the ablation zone and a river runs in front of the
If temperatures increase, as scientists believe they are, then the whole glacier will melt thus draining
the valley and leaving only a river. However, there are tell-tale signs of erosion and features in the
landscape which are evidence of glacial erosion.
How does a glacier erode?
There are three main ways a glacier erodes the landscape:
Abrasion ­ Material carried by the glacier acts like coarse sandpaper on the sides and floor of the
Plucking ­ Ice freezes onto the rock of the valley and, as the glacier moves, the rock is pulled apart.
Meltwater erosion ­ The water underneath the glacier, which has not frozen, carries material that
erodes the bedrock.
Dilation is another method, and it occurs when there is a release in pressure on the ground. The
ground `bounces back.' The underlying rocks expand and crack. This tends to produce cracks which
are parallel to the surface and occurs most commonly in the melting and retreat of glaciers.
Features of glacial erosion
The way glaciers change the landscape creating dramatic features can be incredible. There is
evidence of glacial erosion in the highlands of the UK from the last ice age.
When two adjacent
cirques (corries)
erode backwards into
each other, the
landscape is
transformed into a
steep, rocky ridge.
This is possibly one of
the most obvious of
the glacial features.
Cirques or Corries

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A cirque, corrie or cwm is an `amphitheatre' formation of rock. Snow settles in small hollows on
mountains encouraging freeze-thaw and chemical weathering. The underlying rock disintegrates.
Pyrimidal Peak
If three or more cirques erode into each
other, a peak may be formed with several
arêtes radiating from it. A pyramidal peak is
usually more jagged and upright than other
peaks and mountain tops.
A tarn is simply the collection of
water inside a cirque, which forms a
lake.…read more

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There are two types of valleys formed by glacial erosion: U-shaped valleys and hanging valleys.
U-shaped Valleys
These are the original V-shaped valleys
that have been widened by the glacier.
The movement of the ice causes
over-deepening of the valley floor, as
the meltwater and subglacial debris
have a large erosive power.
Hanging Valleys
The larger the glacier, the more
erosive power it has and therefore the deeper the valley is.…read more

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Ribbon Lakes
If some parts of the glacier are more erosive than others, they may over-deepen parts of the valley
floor. When the glacier melts, a long, deep ribbon lake forms on the floor of the valley.
This is a very steep wall of bare rock found at the back of a cirque. Eventually it will become covered
in vegetation.…read more

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Scree Slope
A scree slope is made up of rocks that have been weathered or eroded and fallen from the valley
above.…read more

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Boulder Clay
This is a random mix of boulders, rocks, sand and clay. The material is transported either on top of or
inside the glacier, and deposited at the base of the valley as the glacier moves. Some of the rocks
are ground down into clay.
Drumlins are formed by the deposition of the boulder clay and have a characteristic tapering shape.…read more

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There are quite a few types of moraines: lateral moraines, terminal moraines, medial moraines. They
are the same thing, but found in different places on the glacier. A moraine is just a string of mounds
of debris being carried along by the glacier. The debris can come from scree on the sides of the
valley, or it can be picked up by the glacier.
Lateral moraines are found on the outside of glaciers, along the edges by the valley sides.…read more

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Words to Know
Ablation Zone:
The area of a glacier where mass is lost through melting or evaporation at a
greater rate than snow and ice accumulate.
Accumulation zone:
The area of a glacier where mass is increased through snowfall at a greater
rate than snow and ice is lost through ablation.
Alpine glacier:
A relatively small glacier that forms in high elevations near the tops of
A sharp-edged ridge of rock formed between adjacent cirque glaciers.…read more

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A U-shaped valley carved out of a V-shaped stream valley by the movement
of a valley glacier.
The transformation of the landscape through the action of glaciers.
A large body of ice that formed on land by the compaction and
re-crystallisation of snow, survives year to year, and shows some sign of
movement downhill due to gravity.
Ground moraine:
A continuous layer of till deposited beneath a steadily retreating glacier.…read more

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The elevation above which snow can form and remain all year.
The long, parallel scratches and grooves produced in rocks underneath a
glacier as it moves over them.
A small lake that fills the central depression in a cirque.
Terminal moraine:
A moraine found near the terminus of a glacier; also known as an end moraine.
The leading edge of a glacier; also known as the glacier snout.…read more


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