AQA A Revision Guide – Ice on the Land
1. What does the term ‘Ice Age’ mean?
A period of time when ice sheets are found
on continents. We still have glaciers on land
today, so strictly speaking we are still in an
Ice Age.
2. How long has the recent Ice Age
lasted?
Scientists believe that the climate has been
similar for the last 2 millions years or so. This
is called the Pleistocene Era. During that
time, the glaciers have advanced and retreated and in doing so has created many impressive landscapes. In fact,
Britain would have looked like Greenland in the past. The maximum extent of the ice is shown on the map above.
3. Are special names given for the periods for when
glaciers advance and retreat?
Yes. Warmer periods are called interglacial periods and colder
periods are called glacial periods. During the most extreme
glacial periods during the Pleistocene, Britain was almost
completely covered by a huge ice sheet. The map on the left
shows this.
4. How do we know the climate has done this?
Glacial landforms found in places like Scotland and the Lake
District = ice must have been there (glacial period).
Similarly, fossil evidence of animals/ plants found in warmer
climates proves that there have been warmer periods
(interglacial period). For example, dig down in Trafalgar Square in London and you found skeletons of Rhino and
Lion. These sediments are dated at just 100,000 years before present (BP).
Another way is to analyse ice core evidence in places such as Greenland. Have you seen the ‘Day After Tomorrow’
film? At the start they were drilling for ice cores. Each year, a new layer of ice is created (a bit like the rings on a
tree), which means that you can drill down and look back in time. Crucially, air bubbles are trapped in the ice and if
you can get to them you can analyse the chemical composition and infer what the climate was like.
5. How is a glacier created?
When snow accumulates, the weight of the snow compresses the air out of the
snow below and this causes snow to turn into a firn. After about 20 years this air
is completely eradicated and the firn turns into a glacial ice. Think of what
happens when you make a snow ball! When you compact the snow together it
becomes denser and becomes more ice-like. Ice that is resting on slopes will
move due to gravity - when the ice begins to move it is called a glacier.
6. Are there different types of glacier?
Yes. A valley glacier is like a river of ice. It flows from high areas and follows the easiest route down – often in preexisting river valleys. An ice sheet is a huge mass of ice that covers a vast area - e.g. Greenland or Antarctica. These
account for 96% of ice on Earth.
7. Glaciers move: how does this happen?
Glaciers move due to gravity. However the
rate of movement is due to the GLACIAL
BUDGET. This is the difference between
the accumulation and ablation of ice each
year. The diagram (left) explains it:
Glaciers have an accumulation (adding
more) zone at the top, where it is coldest.
However, as the glacier moves downhill the
temperature increases and the ice will
melt. This is called ablation (melting).
The balance of the accumulation and the
ablation will determine whether a glacier
moves forward (advance) or move
backwards (retreat) – i.e. as suggested by
the glacial budget.
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8. What example should you use for a glacier that is
changing?
The Mer de Glace (Sea of Ice) in the French Alps- the largest
glacier in France; 7km long and 200 metres deep.
It flows from Mont Blanc towards Chamonix.
It has been getting shorter and thinner since 1850. Advance in
the 1970s and 1980s by about 150 metres has given way to
retreat. It is retreating by about 30 metres a year (500 metres
shorter than in 1994).
Examine the pictures below; 1893 and 2008.
We know the Mer de Glace is retreating through photographic evidence, but also through 19 th Century paintings.
Aerial imagery, old maps and debris left by the glacier all provide evidence of previous positions. The Mer de Glace is
retreating due to climate change. Temperatures are 1⁰C higher than 100 years ago, and 3⁰C higher above 1,800
metres. Combined with drier winters (i.e. less snowfall) the glaciers are melting away.
9. What about other changes to glaciers?
Glaciers change on a seasonal basis too; they tend to
advance in the winter and retreat in the summer.
Therefore, when trying to assess whether a glacier is
in a state of advance or retreat, you really should
compare position from Winter to Winter or Summer
to Summer!
10. How does a glacier shape the land?
There are three main erosion processes; Bulldozing,
Abrasion and Plucking.
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Plucking is where a glacier moves over an area of
rock. Due to friction, the glacier melts and water
seeps into crack around the rocks below. The water refreezes and the rock
effectively becomes part of the glacier and is ripped out when the glacier
continues to move forward.
Abrasion is where rocks at the bottom of the glacier act like sandpaper –
grinding over the bedrock. This can polish the rocks or create sharp grooves
called striations.
Bulldozing is where rocks that are in front of the glacier are physically
removed by the advancing glacier.
11. Where does weathering fit into this?
Weathering is the break down of rock in situ (i.e. no movement) by the process
of the weather. The glaciers do not have anything to do with this process! The
diagram on the right shows this process.
However, the rocks that are shattered from the rock faces in this way can then be used for abrasion or bulldozed
away by the glacier.
12. Landform created by erosion 1: Corries (called Cirques in France and Cwms in Wales)
Often found in North facing slopes. Snow doesn’t melt in the
summer and a glacier forms.
Plucking and freeze-thaw weathering remove rocks from the
backwall making them very steep.
Abrasion occurs at the base when the glacier starts to move
(rotational slip due to the weight) – rocks fed by freeze-thaw
weathering helps this (Bergschrund crevasse allows rocks to fall
through the glacier).
Less erosion takes place at the front of the corrie (less weight), so
a rock lip is formed (moraine can also build up here). When the
ice has gone this feature acts as a dam for a tarn to form.
13. Landform created by erosion 2: Arête
An arête is a sharp ridge cut when two corries either side of a mountain cut back to back.
The back/ side wall of each corries is attacked by freeze-thaw weathering and plucking
leaving a sharp ridge between them.
The picture on the left is Striding Edge in the Lake District.
14. Landform created by erosion 3: Pyramidal Peak
When you have three or more corries surrounding a mountainside, they cut back and
produce this feature. The diagrams below summarise arête and pyramidal peak formation.
15. Landforms created by erosion 4: Glacial Trough, Truncated Spurs and Hanging Valleys
Glacial Trough: due to abrasion, plucking and
bulldozing, the glacier will erode the landscape as
it moves downhill. Glaciers tend to occupy a
former river valley and the erosion turn s the
V=shaped cross section into a U-shaped one.
Truncated Spurs: River valleys have ‘Interlocking spurs’
(pictured right) like the teeth in a zip that overlap. However, a
glacier removes them and makes the valley straight. You can
see the pictured in the diagram above.
Hanging Valleys: If you understand how a glacial trough is formed, then these are quite easy to understand. The
main glacier is the most powerful at eroding the landscape and cuts down quicker than the smaller valley
glaciers that feed into it. Therefore, once the ice has melted away, you are left with a main trough with small
troughs feeding into the main valley. However, the smaller troughs are
way above the main valley as a result of their weaker erosive force.
Waterfalls are often found cascading from the hanging valley into the main
valley (see picture on the left).
16. Landform created by erosion 5: Ribbon Lake
Ribbon Lakes are formed when a glacier moves down a valley and moves
over an area of softer rock. This rock is eroded (abrasion/plucking) far
more easily than the surrounded rock and the valley is over-deepened at
this point. When the glacier retreats the hollow left becomes filled with
water and a ribbon lake is formed. These are long and narrow and occupy the U-shaped valleys – e.g. Lake
Windermere in the Lake District. Ribbon lakes can also be formed by deposition too. When a terminal/
recessional moraine is left by a glacier, this can act like a
dam and trap the water behind to form a lake.
17. How do Glaciers transport material?
Freeze-thaw supplies rock that fall onto the glacier.
Glaciers can also bulldoze rocks in front of it.
18. Why does a glacier deposit material?
When a glacier melts it can lose energy. Any material that is carried can therefore become deposited. Material
that is carried/ deposited by a glacier is called moraine. Depending on the amount of weathering/ erosion that
has taken place on the material this will determine its size. Small, fine sediment is called rock flour, slightly larger
sediment is called boulder clay or till. Large boulders dumped away from their source are called erratics.
19. What depositional landforms are created by glaciers?
Moraines are left by a glacier.
Ground moraine is the layer
left under the glacier. Lateral
moraine is found along both
edges of the glacier; it is the
weathered rock that has fallen
from the valley sides. When
these melt, ridges are left at the
side of the valley. Medial
moraine is where two glaciers
have joined together to form a
larger glacier. The lateral
moraine of the two glaciers will
be in the middle as a result.
When the glacier melts a ridge
will be found along the middle
of the valley. Terminal moraine
is dropped at the end of the
glacier at its snout. This can be
used to show the maximum
extent that the glacier reached.
Moraines are shown on the diagram above, but also drumlins are too – these are discussed on the next page.
Drumlins are formed when glaciers shape the
moraine on the valley floor into small hills. They have
a blunt end and a tapered end. They are found in
swarms and the landscape is described as having a
‘basket of eggs topography’ (see Hellifield in the
Yorkshire Dales on the left).
20. How can you identify glacial features on maps?
Practice your map references and
direction/ distances too!
Corrie with
tarn
Arête
Truncated
Spur (it
would have
gone to
other side of
the valley)
Pyramidal
Peak
Ribbon Lake in
Glacial Trough
The contours give it away. Look back at your exercise books for more information on this.
21. How can glaciated regions be used by people?
The first thing to draw your attention to is that in the revision guide
section about human uses of Fold Mountains (Restless Earth section) is
exactly the same as here. The Alps is your case study for both.
However, we will focus on specific named places and tourism in this
section.
22. What case study can be used for Winter Sports in Glacial
regions?
La Plagne. 120 million visitors go to the Alps each year for winter sports
such as bobsleigh, skiing, snowboarding, rock/ice climbing etc. La Plagne has tapped into this market.
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When: Built in 1960s
Where: French Alps, 2000 metres up
Why: To make money from tourism! It was a good location as the height guarantees snow from December to
April (i.e. long season) and a glacier (Bellecote) which can guarantee skiing, even in the summer.
What other positives does La Plagne possess?: Large selection of bars, restaurant and nightclubs. Variety of
slopes for all abilities. Ski to doorstep. Not just skiing – other winter sports available.
Recent developments: Great access (train, 4 airports nearby and access to motorway network) made it very
popular. It now has six villages all interlinked by a quality lift system. It has even been linked up to Les Arcs to
produce a huge ski area. Expansion was done ‘in-keeping’ with the environment: buildings built in a traditional
style, rather than just building ugly tower blocks.
23. What case study for all year round tourism? Mer de
Glace, Chamonix
Chamonix has Europe’s highest mountain – Mont Blanc. It has a
permanent population of 10,000, but this can swell to 100,000 in
winter (snow sports) and 130,000 in summer.
The reason people go in the summer is the beautiful countryside,
hiking, walking, mountain biking, shops, restaurants and the Mer
de Glace. The Montenvers train takes people to the edge of the
glacier (pictured right). It was built in 1908. Once at the glacier, tourists can experience the ‘Ice Cave’ which has been
carved in the glacier.
24. What are the issues related to tourism in the Alps?
Economic Impacts
Social Impacts
 Thriving economy  Young people stay when
as a result of
they leave education –
tourist spending
many job opportunities
 Tourism is all-  Traditional way of life
year
round.
changed – decline in local
Demand
for
crafts and skills
services
is
maintained
throughout
the
year, creating jobs
Environmental Impacts
 Large amounts of water needed for the resorts for
drinking/ snow making
 Noise from machinery scares wildlife
 Forest cleared for slopes- soil erosion and water
cycle?
 Skiing damages vegetation underneath
 An increase in vehicles has led to air pollution – this
is often trapped in the Alpine valleys. This damages
trees
This has created conflict. Many welcome tourism, whereas others do not. Tourists may be in conflict with each other
if one group wants peace and quiet and the other wants the lively nightlife and sport activities. Conservationists do
not like the damage being done to the environment. Many local people want further development as they can make
more money.
25. How is tourism being managed? (CONTINUATION OF YOUR CASE STUDIES FROM EARLIER)
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LA PLAGNE
CHAMONIX – RESPONSIBLE TOURISM
The council has developed a policy of ‘integrated
New building built in traditional style (wood)
Underground parking – ski to hotel and limits tourism’, which educates and involves visitors and local
people in the protection of the Alpine environment. It:
pollution in the resort
Some of the villages are above the tree line, so
 Free public transport (reduce car usage)
tree cutting not an issue
 Encourage local farming
Avalanche fences built for protection
 Education about the Mer de Glace
Part of the Vanoise National Park- conservation a
key focus
26. What are Avalanches?
An avalanche is a rapid flow of snow down a slope. It can be a natural event of caused by human activities.
27.
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How are avalanches created?
Heavy snowfall
Rise in temperature – weakens the upper layers of snow
Wind direction – can build up snow on one side of the mountain. This overhangs on
one side and can become loose
Slope angle. Most avalanches occur on slopes between 30⁰ and 50⁰.
Type of slope – convex slopes are more prone to avalanches than concave slopes
However, humans can also cause them:
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Off-piste skiing disturbs the slopes, as does walking and climbing
Removal of tress from slopes prevents the snow from being kept in one place too,
thus increasing the risk of avalanches
28. What are the effects of avalanches?
 Loss of life – people buried and die of hypothermia if not found within minutes.
 Injuries – broken bones and other serious injuries
 Buildings buried/ destroyed
 Roads blocked, which slows rescue efforts
29. What can the longer term effects of an avalanche be?
Small avalanches often cause little disruption. However, a major
avalanche can cause serious problems. Fear of a repeat incident can keep
the tourists away. The lack of facilities (destroyed) can also keep tourists
away. A loss of tourists can lead to the failure of businesses and
therefore loss of jobs can occur.
The avalanche at Montroc, near Chamonix, killed 12 in 1999 and
destroyed 20 houses.
30. What is happening to Europe’s glaciers?
The Rhone Glacier in 1920 and 2005
They are retreating. As has been mentioned previously, temperatures have risen by 1⁰C
over the last century and has risen by 3⁰C over 1,800 metres in the last 40 years. The Mer
de Glace is 500 metres shroter than it was in 1994. Winter snowfall is unreliable and the
lower Alps is receiving less total snowfall overall. These will cause real problems for
glaciers.
31. What impact will the retreat of the glaciers have?
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Economic Impacts
Some resorts will no longer be viable as 
Winter resorts- this is a real problem in the
southern Alps. Fewer siightseers and ice
climbers will be a problem in all resorts.
Less tourism will result in less income for the 
area
However, the big, high-altitude resorts, should
prosper as people are forced to go to them.
They have the facilities and amenities already
and the ability to make artificial snow.
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Agriculture could benefit from a higher
snowline and warmer summers – a longer
growing season.
Social Impacts
Jobs could be lost if
tourist numbers fall –
higher
unemployment
With no jobs, young
people will leave to
find work – change in
the
population
structure
Services
could
decline,
but
the
elderly that remain
will demand more
END OF SECTION
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Environmental Impacts
The Alps is a ‘fragile
environment’, whic h means it
is easily damaged. A delicate
balance exists, so the increase
in temperatures/ loss of snow
could mean that it is
unihabitable for some species.
Less water, so river levels will
drop that have their source in
the Alps.
More avalanches
Flooding from melting glaciers
Rock falls as the ground thaws.