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YOUNG FOLD MOUNTAINS AND THE
CHALLENGES FOR HUMAN ACTIVITY
I
MAGINE FINDING THE
FOSSILS of ancient sea
creatures called ammonites and
trilobites high up in the
Himalayas mountain range of
India. This would surely be one
of the last places you would
expect to find signs of sea life!
Many mountain ranges are made
up from rocks such as limestone,
which is a sedimentary rock and
therefore must have once lain at
the bottom of some ocean.
Fossils and sedimentary rocks
give clues to the way fold
mountains were formed. It
appears that the rocks that now
form part of the some of the
most spectacular and biggest
mountain ranges in the world
were once on the sea bed.
The formation of fold mountains
is explained by the theory of
plate tectonics. According to this
theory, the Earth’s outer layer, or
crust, is made up from about 30
‘plates’ which lock together
rather like the pieces of a jigsaw.
About 260 million years ago,
India, Africa, Australia and South
America were all joined together
to form a giant supercontinent
which scientists have called
Pangaea. Over several millions of
years, Pangaea began to break
up, with the biggest plates
making up the continents and
the ocean basins. Because of the
heat generated within the Earth,
the plates are forced to move –
some move away from each
other, whilst others move
together or collide. It is when
the plates collide that fold
mountains are likely to form.
There are some very old fold
mountains, formed early on
when Pangaea broke up, but
by Andrew Gunning
(f)
(a)
(d)
(e)
(g)
(c)
(b)
Figure 1: Fold mountain ranges around the world
there are also some much
younger ones, formed only
between 25 and 10 million years
ago. These fold mountains
include the Himalayas and the
European Alps, creating some of
the most breathtaking and
impressive mountain scenery.
Figure 1 shows the location of
these major mountain chains.
How are fold mountains
formed?
Fold mountains usually form
when two of the Earth’s plates
collide with each other. There
are two ways in which this may
happen:
• when an ocean plate collides with a
continental one
• when two continental plates
collide.
The Andes, which run down the
length of the western side of
South America, are a good
example of the first type, and the
Himalayas are an example of
Series 16 Summer issue Unit 333 Young Fold Mountains and the Challenges for Human Activity © 2005 Nelson Thornes
This page may be photocopied for use within the purchasing institution only.
two continents, once separated
by an ocean, colliding.
Whichever way the plates
collide, the effects are basically
the same.
As the plates move together, the
land, as well as all the
sedimentary rocks and sediments
lying on the ocean floor between
them, are crumpled or folded to
create a series of mountain ridges
separated by valleys (Figure 2). It
takes millions of years to form
the high mountains we see today
and the intense heat and pressure
resulting from the folding causes
many of the rocks to be
metamorphosed, or changed.
Frequently volcanic material is
able to force its way through
cracks and erupt, adding even
more height to the mountains.
The Andes have hundreds of
active volcanoes along their
length. Often the folding is more
severe and the pattern of high
mountain ridges and valleys
becomes a little more complex.
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Plates move towards
each other
N
Simple fold
C
( T H
I BI N
E A
T
)
Annapurna
Ancient ocean
N
Ocean floor begins
to fold
E Katmandu
P
A
I N
D I
A
Overfold
Mt Everest
L
Key
Volcanic material moves up
0
200 km
Himalayas
mountain range
Figure 2: The formation of fold
mountains
Figure 3: Types of folding
Figure 4: Nepal
If you go to the Alps you might
see evidence of the folding in the
exposed rock faces (Figure 3).
world are not as high or as big as
the most recent ones. Some of
the ancient fold mountains in
Scotland are all that remain of
once much higher ones.
The problems have been made
worse by rapidly rising
populations, particularly in less
economically developed
countries (LEDCs), causing
increased pressure on the land.
The challenges facing
governments and planners are to
try and improve the quality of
life for the local people and at
the same time preserve the
environment.
The story behind the formation
of the Himalayas is a fascinating
and remarkable one. About 140
million years ago, India was not
part of the continent of Eurasia
(Europe and Asia), but was
somewhere to the south.
Gradually it began to drift
northwards, squeezing the rocks
and sediments of the sea floor
upwards. This accounts for the
discovery of the ammonites and
trilobites in the Himalayas. Over
a period of about a million years,
the land has been pushed up
nearly 5,000 m. The collision
between India and Eurasia is still
going on today! Scientists
calculate that India is still moving
northwards at about 18 mm a
year and that the Himalayas are
still growing in height at about
4 mm a year. This means that
Mount Everest is now 20 cm
higher than it was when Sherpa
Tensing and Sir Edmund Hillary
first climbed it in 1953. The
movement sometimes triggers
earthquakes in countries like
Pakistan and India.
Once mountains have been
formed and are pushed high up
into the atmosphere, they start to
be weathered and worn away by
the effects of frost, glaciers and
rain. This explains why the
oldest fold mountains in the
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The challenges for human
activity
Mountain environments are very
fragile, yet they are vital to life a
long way beyond them, because
they are the source of fresh water
for nearly half the world’s
population. The rivers and
streams which flow from
mountain regions link the
mountains to the lowlands where
the vast majority of people live.
They also have a huge range of
both plant and animal life. But
mountains are under threat
from:
• climatic change
• environmental damage
• overexploitation by local people
who need resources.
Almost without exception,
mountain areas are difficult
places in which to live, work,
survive. Such places are always
going to be badly affected by a
number of problems:
• a poor climate
• poor soils
• poor communications
• steep slopes
• increased risk of hazards such as
landslides.
Case Study
Challenges in the Himalayas
– Nepal
Nepal is a small, rectangularshaped country sandwiched
between the giants of India and
China (Figure 4). Almost twothirds of the country is classified
as mountains or hills. In 2001
Nepal had a population of 23.3
million, an increase of over
5 million in the ten years since
1991. The rapid growth of
population and the limited
resources available make Nepal
one of the poorest countries in
the world. The situation is not
likely to improve in the future, as
42% of the population is under
15 and the population is
expected to continue growing
rapidly. Many of the issues
involved in finding the balance
between development and
maintaining the environment are
linked, and they represent a
significant challenge.
Series 16 Summer issue Unit 333 Young Fold Mountains and the Challenges for Human Activity © 2005 Nelson Thornes
This page may be photocopied for use within the purchasing institution only.
The challenges and possible
solutions
Tibet
(China)
Him
ges
R. Gan
N
Nepal
ala
yas
Bhutan
India
ra
maput
R. Brah
Bangladesh
Himalayas – 5,000 m
above sea level
R. Meghna
Bay of Bengal
Large runoff, particularly in spring
when the snow melts
Deforestation on foothills of Himalayas reduces
loss through evapotranspiration – runoff
remains high
Densely populated fertile Bangladesh
lowlands
River floods, large number
of deaths
Bay of Bengal
Figure 5: How the Brahmaputra causes flooding
Deforestation
Deforestation is the removal of
trees and forests. This has been
going on in Nepal for hundreds
of years, but as population
numbers have risen and the
demand for food has increased,
so more trees have been removed
and at a rate that was becoming
unsustainable. The loss of the
trees exposed an already thin and
fragile soil which in times of
heavy rain was quickly washed
away into the rivers. The rise in
tourism has increased even
further the demands for wood as
a fuel and the need to create
places for campsites. The
problem of flooding on a major
scale is felt outside Nepal. As
runoff increases due to the loss
of vegetation, tributaries flowing
south out of Nepal combine to
flow through the low-lying
regions of north-east India and
Bangladesh. Rivers such as the
Ganges and Brahmaputra have
overflowed and caused some of
the world’s worst floods in
history (Figure 5).
Biodiversity
The Himalayas are home to a
rich variety of plants and animals
and governments have often
overlooked the importance that
mountains play in sustaining
much of this biodiversity. In
Nepal alone there are over 2,000
different varieties of rice, for
example. The clearance of
woodland and pollution of water
and the land by tourists have
caused many species to be lost.
Tourism
Tourism has increased rapidly in
Nepal and most people come to
mountaineer or trek in the
breathtaking scenery. Tourists
bring in much needed revenue
both for the local people and for
the government. It is estimated
that on average two Nepalese
help every single tourist on their
trip in the country. However,
tourism brings its own problems.
Tourists need places to stay and
eat and this has led to loss of
valuable farmland. Despite
concerted efforts to prevent it,
tourists drop non-biodegradable
litter. In five years, over 770
tonnes of litter were collected
from the area around Mount
Everest. Human waste pollutes
both the land and the rivers.
Local traditions and cultures are
suffering too, as local people
prefer to work for tourists rather
than in their villages and on the
land.
Series 16 Summer issue Unit 333 Young Fold Mountains and the Challenges for Human Activity © 2005 Nelson Thornes
This page may be photocopied for use within the purchasing institution only.
How can a balance be struck
between these conflicting
interests? One answer has been
to create a conservation area like
the Annapurna Conservation
Area, which was established in
1986 and is now visited by over
86,000 people a year. It does not
exclude people from the
conservation area and tries to
involve local people as much as
possible. Trekkers pay a fee to
enter the area and this is used to
fund the project. The money is
used to provide assistance and
training for local people, such as
learning about the necessity to
boil water, and energy
conservation. Education about
the area is provided for the
tourists. People will always want
to see these places and it is better
for local communities to have a
say in how fast tourism grows.
However, it is not all good news:
the Chinese want to construct a
major road and this will cost
more in terms of environmental
damage than in economic
benefit. The conservation area
directors are powerless to stop it.
Conclusion
One of the biggest challenges in
big fold mountain regions is to
allow these areas to develop in a
sustainable way which brings
benefit not only to the local
community, but also provides for
the needs of the tourists and the
tour companies. However, there
are challenges which will require
the co-operation of many
governments around the world,
such as dealing with global
warming which has led to the
melting and retreat of many of
the big glaciers that provide fresh
water and, of course, which
tourists come to see.
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Activities
Revenue for
country
Litter
1 On Figure 1, the major fold
mountain ranges are shown by
the letters a–g. Using an atlas,
identify each of these.
2 Make a large, neat copy of
Figure 2, adding the labels. The
statements below give some
additional information for the
diagrams. Read through the
statements and decide which
diagram each one corresponds
to. Add the correct statement to
your diagram.
A The intense pressure causes both
simple and overfolds.
B Sediments are laid down in
horizontal layers on the sea bed.
C The ocean begins to disappear and
then fold.
3 Explain why both volcanoes
and earthquakes can occur in
some fold mountain areas.
4 Using the information in this
unit, calculate how much the
Himalayas have grown per year
in the last 1 million years.
5 Study Figure 6.
(a) Construct a suitable graph to
show this information.
(b) Describe the pattern or
trends shown by the graph.
(c) How does the increasing
population density affect the
natural environment in Nepal?
6 Copy Figure 7 and add some
other benefits and problems to
it.
Year
Density per km2
1911
38
1921
38
1931
37
1941
43
1951
56
1961
64
1971
78
1981
102
1991
126
BENEFITS
PROBLEMS
Figure 7 Benefits and problems tourists may bring to Nepal
7 Explain what is meant by the
terms biodiversity and
sustainable development.
8 The challenge in the
Himalayas is to find a balance
between the conflicting demands
of the need for more money for
the country as a whole, the needs
of the local people, and the
demands made by groups of
tourists. The class should work
in three groups:
• one group represents the
government which needs to raise
money for the country’s
development
Extension activities
9 The European Alps are
another major fold mountain
range, but they are located in a
number of wealthy MEDCs.
How do you think the challenges
they face differ from those faced
in a country like Nepal?
10 Research the names and
types of plate whose movement
has led to the formation of the
Andes in South America and the
Rockies in North America.
• another group represents the needs
of the local communities and
farmers
• the final group represents the
tourist companies.
Each group should put together
a presentation, perhaps using
ICT, to show how it will meet
the challenge of satisfying the
conflicting demands.
Figure 6: Population density in
Nepal, 1911–91
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Series 16 Summer issue Unit 333 Young Fold Mountains and the Challenges for Human Activity © 2005 Nelson Thornes
This page may be photocopied for use within the purchasing institution only.