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2014 Revision Guide - Mountain Environments
1. What do we know about mountains?
1.1 Physical characteristics
Altitude and gradient
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Elevation, volume, steepness, and spacing have been used
as criteria for defining a mountain.
Mountains cover 24% of the Earth's land mass.
10% of people live in mountainous regions.
Most of the world's rivers are fed from mountain sources,
and more than half of humanity depends on mountains for
water
Weather and climate
Tall mountains have different climatic conditions at the top than at
the base.
Different elevations have different ecosystems
At the highest elevations, trees cannot grow, and whatever life may
be present will be of the alpine type.
Below the tree line, you may find subalpine forests of needle leaf
trees, which can withstand cold, dry conditions
1.2 Human factors
Population density
Mountains are sparsely populated regions (not many people live there)
because of:
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Harsh weather
Steep land – hard to farm
Less Oxygen
Economic activity
Many mountains and mountain ranges throughout the world
have been left in their natural state.
Used for :
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Recreation – Tourism
Logging
Mining
Sheep grazing.
Mountains have little economic activity.
People who live and work in mountains
Like deserts, mountains are used by similar groups of people.
Multinational mineral companies, indigenous groups and also
tourists.
Mineral companies are keen exploit the rich mineral reserves
in mountains to make profits.
Indigenous groups like the Aymara in the Andes often live in
small communities as subsistence farmers.
Tourism in mountain environments can offer governments a large source of foreign income and also
provide employment opportunities. Although, just like desert environments, mountains can many
pose many challenges for humans to overcome.
1.3 Cultural representations
Mountains are often used in a range of cultural resources including films, photography, expedition
accounts and poetry. Each of these different cultural resources will use mountain environments for
their own particular purposes but all will aim to use the characteristics of mountain environments
such as their natural landscape, climatic extremes or hazardous conditions to create particular ideas
in the mind of the viewer. For example, there are many great poems about mountains the sublime
majesty of mountains has inspired history’s best minds, proving William Blake’s (a famous British
poet) quote, “Great things are done when men and mountains meet.”
2. Where are mountains found?
2.1
Distribution and examples
You will need to be able to locate the following mountain ranges on a world map Rockies,
Andes, Alps, Himalayas, Great Dividing Range, Pyrenees and Atlas.
2.2What is the relationship between plate boundaries and mountain ranges?
As you can see from the
map opposite, most of the
planets mountain ranges
are found close to the
Earth’s plate boundaries. Collision plate
boundaries and destructive plate boundaries all
form mountains but are created by slightly
different processes.
Collision plate boundaries
Each year rivers wash tonnes of sediment into the sea. The sediments collect at the bottom
of the ocean in depressions called geosynclines and are compressed into layers of
sedimentary rock such as limestone and sandstone. At a collision plate boundary the plates
move towards each other forcing the layers of rock up in a series of folds. This movement of
plates can also cause earthquakes. Examples of a mountain range formed in this way is the
Alps and the Himalaya
Destructive plate boundaries
At destructive plate boundaries, oceanic plates
meet continental plates. The denser oceanic
plate is pushed beneath the lighter continental
crust, this movement is known as subduction.
This causes the lighter continental crust to
crumple upwards creating mountain ranges.
The Andes are an example of a mountain
range created in this way. The friction
between the two plates can also cause
earthquakes and as the oceanic crust is
destroyed the molten rock forces its way
through cracks in the crust to create
volcanoes.
3. What are mountain climates like?
There are three main factors which can affect mountain climates. These are altitude, relief,
and aspect.
3.1 The altitude in a mountain environment can have a significant impact on temperature as
temperatures will decrease with height. This is because the atmosphere is much better at
trapping heat at sea level.
3.2 The relief, or the shape of the land can also
impact on the amount of rainfall in
mountain environments. Where there is one
prevailing wind direction, on the windward side
of mountain ranges air will be forced to rise. As
it does so water vapour will condense bringing
cloud and rain. On the leeward side of the
mountain, the air will now contain less water
vapour and so precipitation will be less likely.
3.3 The aspect can also impact on
temperatures in a mountain environment. In
the Northern hemisphere, south facing
slopes will get the most sunshine during most
of the day, however northern facing slopes
will be more shaded. This means the daytime
temperatures for southern facing slopes will
be higher than the colder, northern facing
slopes.
4. What are mountain landscapes like?
Mountain landscapes are an excellent example of how the Earth’s major physical systems all
work together over very long periods of time to create the mountain landscape features we
can see today. To really understand what mountain landscapes are like, you will need to
apply your knowledge of a number of physical processes such as tectonics, rivers and ice.
4.1 Freeze thaw weathering and scree slopes
Scree slopes are a collection of broken up rock
fragments usually found on the slopes of mountains.
When water - e.g. from rainfall or melting snow
and ice - becomes trapped in a crack or joint in
the rock, it freezes and the ice expands by 9-10
per cent putting pressure on the rock. If this
process happens repeatedly, the rock will
weaken and eventually shatter into angular
fragments creating a scree slope.
4.2 What impact does water have on mountain landscapes?
As mountain chains are formed by tectonic process and the movements of the Earth’s crust.
The uplifted crust is also attacked by water from the planet’s atmosphere as it flows over
the crust as a river.
What physical processes create V shaped valleys and
interlocking spurs?
In mountain environments you often find high levels of
precipitation and as a result, the source, or start of
many of the Earth’s river systems. As the river moves
through its upper course it erodes downwards through
the process of abrasion. Over long periods of time, this
helps to create the typical V shape you can see in the
image opposite.
What are interlocking spurs?
As the river erodes the landscape in
the upper course, it creates a second
landscape feature called interlocking
spurs. This are formed as the water in
the river winds and bends to avoid
areas of hard rock. These interlocking
spurs, often look a bit like the
interlocking parts of a zip.
4.3 What impact does ice have on mountain landscapes?
Depending on regional or global climate change, latitude or the amount of uplift taking
place, ice may form to create a glacier. A glacier is a mass of ice that moves very slowly
downhill. They are found at high altitude, mountains across the globe, even on high
mountains close to the equator. Interestingly, glaciers can also be found at lower altitude in
high latitudes close to the North and South Poles. The formation of glaciers and the process
by which they shape the landscape around them is called glaciation.
There are three processes by which glaciation affects the landscape – erosion,
transportation and deposition.
What are the processes of glacial erosion?
Glaciers have a huge impact on landscapes. They exert colossal forces on the land and are
responsible for dramatic changes caused by erosion.
Plucking occurs when rocks and stones become frozen to the base or sides of the glacier
and are plucked from the ground or rock face as the glacier moves. It leaves behind a jagged
landscape.
Abrasion occurs when rocks and stones become embedded in the base and sides of the
glacier. These are then rubbed against the bedrock (at the bottom of the glacier) and rock
faces (at the sides of the glacier) as the glacier moves. This causes the wearing away of the
landscape as the glacier behaves like sandpaper. It leaves behind smooth polished surfaces
which may have scratches in them called striations. Striations are carved out by angular
debris embedded in the base of the glacier.
How are glaciers formed? - Corries / cirques
Corries, also known cirques, are often the starting point of a glacier. The diagram below
shows the formation of a corrie or cirque.
A corrie is an armchair shaped hollow, high on a mountain with steep back and side walls.
After glaciation, the hollow may be filled by a small
lake or tarn.
Snow gathers in mountain hollows, especially north
facing hollows, where there is more shade. This
snow builds up and compacts to ice (neve).
The action of gravity means the ice moves down the
hill. As it goes, it sticks to back walls and plucks rock
from the surface. Rocks on the backwalls are
loosened by freeze-thaw action. A gap between the
wall and the ice develops, called a bergschrund. Ice
moving with loose rock acts like sandpaper and deepens the hollow by abrasion. Most
erosion is where the weight of the ice is the heaviest. Stones frozen in the base of the ice
grind or abrade the corrie base, deepening it. Some of this debris is deposited at the edge of
the corrie, building up the lip.
These processes create a characteristic rounded, armchair shaped hollow with a steep back
wall. When ice in a corrie melts, a circular lake is often formed at the bottom of the hollow.
This is known as a tarn
What are Arêtes and pyramidal peaks
An arête is a knife-edge ridge. It is formed when two neighbouring corries run back to back.
As each glacier erodes either side of the ridge, the edge becomes steeper and the ridge
becomes narrower
A pyramidal peak is formed where three or more corries and arêtes meet. The glaciers have
carved away at the top of a mountain, creating a sharply pointed summit, eg Mont Blanc,
The Matterhorn and Mount Everest.
U shaped valleys and Glacial troughs
Once enough ice has formed, glaciers will move very slowly through the valley system
created by water. However, once the ice retreats, it is revealed that the glacier created a
distinctive U-shaped valley. These have which have a flat floor and very steep sides. The
glacier widens, steepens, deepens and smoothes the existing V-shaped river valleys. The
images below show the difference between a U-shaped valley and a V-shaped valley.
Just like rivers, glaciers have tributaries. As the main glacier erodes deeper into the valley,
the tributary is left higher up the steep sides of the glacier. U-shaped valleys ending with a
waterfall at the cliff-face are called hanging valleys.
As we saw previously, when a river erodes the landscape, ridges of harder more resistant
rock form in its upper course which jut into the river called interlocking spurs. As a glacier
makes its way through a valley it’s power is great enough to cut through these ridges leaving
behind truncated spurs.
Valley floor landforms
As a glacier flows over the land, it flows over hard rock and softer rock. Softer rock is less
resistant, so a glacier will carve a deeper trough. When the glacier has retreated, (melted)
water will collect in the deeper area and create a long, thin lake called a ribbon lake. Many
of the lakes in the English Lake District are ribbon lakes, eg lake Windermere.
Following glacial retreat, former glacial valleys are often re established as river systems, but
as they now have a much wider, flatter valley floor it leads to the formation of flood plains.
These are areas of flat land which are exceptionally prone to flooding. However, persistent
flooding over time leads to the development of very rich and fertile soil on which to grow
crops.
4.4 What do glacial deposition landforms look like?
Moraines
When glacial ice melts, different types of rock are laid down that have been carried along by
the glacier. Piles of these deposits are called moraines
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Terminal moraines are found at the terminus or the furthest (end) point reached by a
glacier.
Lateral moraines are found deposited along the sides of the glacier.
Medial moraines are found at the junction between two glaciers.
5. How do people use mountain environments?
5.1 Just like hot desert environments, mountains are certainly challenging for humans to
survive in and pose specific challenges relating to accessibility, transport, altitude, gradient,
food and water supply. We have examined three named groups of people who use the Alps
for different purposes.
(i) Local inhabitants who use the Alps in a variety of ways,
(ii) The positive and negative impact of tourism in the Alps.
(iii) Climate scientists examining glacial retreat and the impact of climate change,
5.2 How do local inhabitants use the Alps?
Farming
Mostly on the valley floor
where it is flatter, more
sheltered, warmer, with
deeper soils
Traditionally dairying
Main crops re hay and cereals
with some vines and fruit in
warmer areas
Use upland pastures in
summer.
HEP and industry
Industry needing large
amounts of electricity, e.g.
sawmills, smelters, locate near
to HEP stations which
generate cheap electricity
from the fast flowing streams
Traditional industries include clock making, paper and furniture.
Forestry
Conifers cover the slopes up to about 1800 metres. The wood is used for fuel, building
chalets and for paper-making.
5.3 Climate scientists
Increasing amounts of CO2 in the atmosphere as a
result of burning fossil fuels like oil and gas are
enhancing the greenhouse effect and trapping heat in
the atmosphere and raising average global
temperatures across the planet. The melting of Alpine
glaciers and the speed at which they move is acting as
an excellent indicator for climate scientists to use as a
measure of how much the planet is warming.
As the planet warms, glaciers in the Alps
begin to melt which causes melt water on
the surface of the glacier. Some of the water
travels down large cracks in the ice called
Moulins. The water flows to the base of the
glacier, lubricating the ice and making it
move faster down the mountain slopes. This
means the glacier sits in lower altitudes,
triggering more melting, more Moulins and
faster moving Alpine glaciers.
5.4 Impact of tourism
Ski tourism has many positive impacts on the Alps such as...
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Creation of employment opportunities
Reduction of migration to larger Alpine urban areas
Conservation and protection of the Alpine natural environment
Improvements in infrastructure and services in Alpine mountain environment
Local Alpine products and cultural identity maintained.
However, Ski tourism in the Alps can bring several disadvantages including...
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Increased use of snow cannons putting massive pressure
on water supply in some low lying resorts.
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Massive energy requirement to spread snow onto the
slopes for skiing. It has been calculated that due to snow
cannons, a family of four will consume ten times as much
electricity on a two-week skiing holiday as they would if
they stayed at home!
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The movement of water onto slopes can negatively impact
plants and soil. The use of an additive to reduce the speed
of melting from snow cannons has an unknown effect on
plants and animals in the Alps.
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Ski installations do little for the visual attractiveness of the
Alps and large ski runs displaces many plant and animal
species.
6. What are the alternative futures for
mountain environments?
6.1 Mountains as a resource
Mountain environments although
challenging are an essential resource for
humans to use. Mountains are an important
component of the hydrological cycle and as
a result contribute to the production of
resource our fresh water supply. This is
because mountains have two important
functions, they encourage precipitation and they also store water in the form of glaciers.
In terms of storing water, nearly 69% of the planet’s fresh water is stored in glaciers and ice
caps which are often found in mountain environments.
Secondly, mountain environments force air to rise which means that water vapour in the
atmosphere condenses and brings precipitation. This provides essential water for human
survival either for drinking, income, energy or growing food. One in two people on the
planet depend on mountain water in one way or another.
In addition, the fast flowing rivers down mountain
slopes can be used to generate hydroelectric
power. With their location at some destructive
plate boundaries, mountains can also be used for
geothermal energy production.
6.2 Management of mountain environments
Following your investigations you will have noticed that there are sustainable ways we can
manage mountain environments for the future but also ways in which some human
activities have led to several negative and unsustainable impacts.
Sustainable management of mountain environments
Sustainable management of mountain
environments would involve using mountains
for energy production. Hydroelectric and
geothermal energy would could be considered a
sustainable use of mountain environments as
they would not release any further CO2 into the
atmosphere hopefully reducing average global
temperatures for the future.
As mountain environments will almost certainly
remain attractive to tourists, using the principles
of ecotourism, similar to desert environments
would also be a more sustainable way to use
mountain environments in the future.
Unsustainable management of mountain environments
As you saw when you investigated the impacts of tourism, while it brings some advantages,
tourism, if not managed sustainably can lead to several negative social, economic and
environmental impacts. As climate change is causing the snowline to creep higher and
higher up mountain environments, as it migrates, lower lying ski resorts are becoming less
desirable to tourists and further higher altitude resorts are developed.
With the snowlines pushed to higher altitudes, similar shifts are taking place in all the other
ecosystems found at particular altitudes. Recently scientists have seen an explosion in the
number of mosquitoes which can now survive in higher altitude areas increasing the risk of
malaria and other diseases in mountain environments.
The impact of climate change is also causing glaciers to
melt causing problems with longer term sustainability of
water supply from mountain environments.
The future of mountain environments like the Alps are
very much connected to the impacts of climate change a
world with warmer average atmospheric temperatures.
Mountain environments exam practice
Justify why mountain environments can be described as extreme (2marks)
Describe three characteristics mountain environments (3 marks)
Suggest reasons why mountain environments are often represented in media such as
paintings, music, literature and film (4 marks)
Name and describe one landform or physical feature in a mountain environment. You may
draw a labelled diagram to help you (4 marks)
Name one physical process which shapes the landforms in a mountain environment.
Describe this process and explain how it shapes the landforms. You many draw a labelled
diagram. (6 marks)
Describe three ways in which people use mountain environments (3 marks)
Explain why mountain environments are challenging for different groups of people (6 marks)
You have been asked to organise an expedition to a mountain environment. Identify and
justify ONE essential survival item that you would take (2 marks)
Identify ONE source of information that you found useful when studying a mountain
environment. Explain how it helped your understanding of the extreme environment. (2
marks)
Name an area of a mountain environment that you have studied. What would be your
feelings about staying there? Explain your views, using specific information about the area.
(6 marks)
In what ways do you think mountain environments may change in the future? Describe and
explain the impact of these changes. (8 marks)
To what extent are you optimistic or pessimistic about the future of mountain
environments? (8 marks)
For a named mountain area you have studied:
i) describe how it is used by people and explain why it is used that way (6 marks)
ii) To what extent is the use of this area threatening to either indigenous cultures or the
natural environment?
Explain how climatic change may cause problems for people in mountain environments (4
marks)
“Global warming blamed for loss of animal habitats”
27 February 2007
Outline sources of carbon dioxide in the atmosphere, and explain how the theory of global
warming could be responsible for one of the headlines above. (9 marks)