Transcript Landforms

Unique landforms
occur at plate
margins
Location and formation of ocean trenches,
shield volcanoes, composite volcanoes and
fold mountains.
Volcanoes are Hazards resulting from
tectonic activity. Their primary and
secondary effects are positive as well
as negative. Responses changes in
the aftermath of an eruption
CASE STUDY: Soufrierre Hills,
Montserrat
Trenches are found adjacent and parallel to continents and island
chains. At least 22 trenches have been identified although not all are
classified as major. Of this number, 18 are in the Pacific Ocean, three
in the Atlantic Ocean, and one (the Java Trench) in the Indian Ocean.
Depths of major trenches exceed 18,000 feet, and vary from 10 to 22
miles in width. The deepest is the Challenger Deep, 35,810 feet deep, in
the Marianas Trench. The depths of many trenches are greater than the
elevation of the world's highest mountain.
Ocean trenches happens at areas where two plates collide, a
DESTRUCTIVE plate margin. The denser oceanic crust to sinks or slips
beneath lighter continental crust. Trenches are formed by the process
of SUBDUCTION. Oceanic crust/plate is made up of heavy material
(basaltic rocks). Along a collision plate boundary, thinner, denser
oceanic crust is squeezed down and subducted along the subduction
zone and melts in the magma of the upper mantle. Subduction
produces a deep Ocean Trench on the ocean floor, parallel to the plate
boundary.
Destructive Margin
Describe the differences in shape between
Volcano A and B.
One is a SHEILD volcano the other is a
COMPOSITE volcano
COMPOSITE
SHIELD
Steep sides
Gentle sides
Narrower
Wide
Violent Eruptions
Gentle eruptions
Ash and Lava
Lava and a little ash
Lava thick acidic
Runny basic
Erupts infrequently
Erupts frequently
What do you notice about the
location of the two volcanoes?
How do the relative positions
of the volcanoes help
understand their different
shapes?
Composite Cone
Mt St Helens - USA
Crater
The volcano is built up
of alternate layers of
LAVA and ASH. They can
explode with great
violence.
Pyroclastic Flow
Ash layer
Lava Layer
Conelet
Dyke
Flank
eruption
Lava
Flow
Crust
Composite Cone
Mt Ranier - USA
The volcano is built up
of alternate layers of
LAVA and ASH. They can
explode with great
violence.
Mt St Helens - USA
Shield ( Basic) Cone
Mauna Loa Hawaii -USA
Shield Volcanoes are enormous features
built up only from layers of lava. They
produce lots of lava but they tent not to
erupt violently.
Layers of Lava
Lava Flow
10,000m
250 miles
Composite volcano to scale
Shield ( Basic) Cone
Mauna Loa Hawaii -USA
Shield Volcanoes are enormous features
built up only from layers of lava. They
produce lots of lava but they tent not to
erupt violently.
Describe how FOLD MOUNTAINS are formed. Foundation
June 09
The plates move
together (a collison
margin) forcing the
sedimentary rocks
upwards in a series of
folds
Over millions of years
the sediments were
compressed into
sedimentary rocks such
as sandstone and
limestone.
Rivers deposited huge
quantities of
sediments in
depressions called
geosynclines
Explain the formation of young fold mountains.
Higher June 09
Statements relating to existence of large depressions
calledgeosynclines. The erosion of material from land
surface by rivers / accumulation of material on seabed.
Further layers of material being added as the erosion
process continues / being compressed into rock by weight
of particles / sea above.
The movement of plates together – compressional
(destructive) boundary/sediment being crumpled into fold
mountains / anticlines and synclines forming.
(4 marks)
Diagrams are worthy of credit.
Level 1 (Basic) (1-2 marks)
An idea of how fold mountains form. Separate statements.
Partial sequence – likely to refer to end of it, rather than the start,
e.g. material collects under the ocean. Plates shift together and
material is folded into mountains.
Level 2 (Clear) (3-4 marks)
Describes clearly how fold mountains form. Linked statements.
Complete sequence – links aspects of last two points to first two,
e.g. material is eroded from the land by rivers and transported to
the sea. Here, in a geosyncline the material is deposited and
compressed by the weight of further layers and the water into rock.
The plates move together and the material folds creating anticlines
and synclines present in fold mountains.
Collision Margin
Plates: Indo-Australian and Eurasian
E.g. The Himalayas
Use an atlas to complete the labels.
TRUE OR FALSE
There are no fold mountains in Africa.
The land next to the Pacific Ocean has many fold mountains.
The Andes are found at a destructive plate boundary.
Describe the world distribution of young Fold Mountains.
Foundation June 09
Any 2 valid facts from Figure 4, Credit positives only.
Max one mark for plate boundaries using correct context.
there are a lot along the west coast of the Americas;
they cluster around the Pacific Ocean;
there is a band to north, east and west of India;
there is only one range in North Africa.
People use these landforms
as a resource and adapt to
the conditions within them
People use these landforms as a
resource and adapt to the conditions
within them.
Give a reason(s) why one type of human activity happens in fold
mountain areas. Name of human activity (2 marks)
Give a reason(s) why one type of human activity happens in fold
mountain areas. Name of human activity (2 marks)
Give a reason(s) why one type of human activity happens in fold
mountain areas. Name of human activity (2 marks)
Foundation June 09
Valid human activities are arming, forestry, tourism, HEP and industry.
Farming and tourism likely to be dominant. No mark for naming human
activity. 2×1 for description, e.g. Farming favours south facing
slopes (1). Cattle are kept on high slopes during summer (1)
and brought down to lower areas where they are kept inside
during the cold, snowy winter (1).
Level 1 (Basic) (1-2 marks)
• An idea of how fold mountains form. Separate statements.
• Partial sequence – likely to refer to end of it, rather than the start, e.g.
material collects under the ocean. Plates shift together and material is
folded into mountains.
Level 2 (Clear) (3-4 marks)
• Describes clearly how fold mountains form. Linked statements.
• Complete sequence – links aspects of last two points to first two, e.g.
material is eroded from the land by rivers and transported to the sea. Here,
in a geosyncline the material is deposited and compressed by the weight of
further layers and the water into rock. The plates move together and the
material folds creating anticlines and synclines present in fold mountains.
Add a sentence to match each box
First box – statement relating to existence of large depressions
(geosynclines); the erosion of material from land surface by
rivers ; accumulation of material/sediment on seabed.
Second box – statement relating to further layers of
material/sediment being added; being compressed into rock by
weight of particles / sea above.
Third box – statement relating to movement of plates together;
sediment being crumpled into fold mountains; anticlines and
synclines forming.
3×1. One acceptable statement per box.
Foundation June 08
Mount St Helens is part of the Cascade Range of young fold
mountains. Complete the sentences below to explain how fold
mountains are formed. Choose the correct words from the list.
Eroded sandstone
apart
together
deposited
plate boundaries
ocean ridges granite
Fold mountains are formed along ............................. . Over millions of
years, thick sediments were .......................... in huge depressions. The
sediments were compressed into solid rocks such as.................. . The
plates moved ............................ forcing the rocks upwards into fold
mountains.
(4 marks)
Describe the human activities in an area of young fold mountains that
you have studied (4 marks)
Foundation June 04
Fold mountains are formed along plate boundaries. Over millions of
years, thick sediments were deposited in huge depressions. The
sediments were compressed into solid rocks such as sandstone. The
plates moved together. forcing the rocks upwards into fold mountains.
(4 marks)
Describe the human activities in an area of young fold mountains that
you have studied (4 marks)
Point mark (4 × 1) or developed points. Reserve of one mark for example
(not Cascades) e.g. Alps, e.g. In the Alps (1) there are ski resorts (1) and lots
of people go on holiday in the winter. In summer they visit the lakes (1) e.g.
Lake Como. (1) HEP (1) uses the fast running streams (1). Hay and vines
are grown (1) in the valleys in summer and cattle graze the hilltops. (1) Max
2 on tourism. Max 2 for list.
Foundation June 04
Foundation June 04
What type of volcano is Mount Fuji?
Shield
Add labels to describe the volcano.
Box X – crater / flat top; box Y – steep sides / cone shaped.
Volcanoes can occur in fold mountain ranges. Figure 5, on the insert, shows
Mt Fuji in Japan.
In the space below, draw a labelled sketch of Figure 5 to show the features of
this volcano.
HigherJ une 09
1 mark for drawing sketch shape – which should resemble
clearly the profile in Figure 5. Use S for shape mark.
2×1 for appropriate labels – such as crater / shape of land here;
steep sides; cone shape, ridged appearance.
3 marks
HigherJ une 09
Volcanoes can occur in fold mountain ranges. Figure 5, on the insert, shows
Mt Fuji in Japan.
In the space below, draw a labelled sketch of Figure 5 to show the features of
this volcano.
HigherJ une 09
Many earthquakes have occurred around the edges of the Pacific Ocean.
There have been many earthquakes in Northern Europe.
There is a line of earthquakes through the middle of the Atlantic Ocean.
(3 marks)
June 05
Study Figure 11, on the insert, photographs of the Franz Josef glacier area
in New Zealand.
Describe how the area provides an opportunity for one tourist activity.
(2 marks)
Describe the environmental problems caused by tourist activities in upland
glaciated areas.
(4 marks)
June 09
Study Figure 11, on the insert, photographs of the Franz Josef glacier area
in New Zealand.
Describe how the area provides an opportunity for one tourist activity.
(2 marks)
Describe the environmental problems caused by tourist activities in upland
glaciated areas.
(4 marks)
June 09
Any 1 valid opportunity, e.g. the glacier offers a unique area to visit
/ see firsthand (1) and experience walking on it/ice is clearly very
deep / formed into shapes. (1) Quad-biking (1) is another activity –
on the area near to the glacier and allowing own transport to view
glacier in a different way. (1) (2 marks)
Erosion of land surface is likely with quad-biking; disturbance to
wildlife and impact on habitat; the number of visitors being
encouraged to fairly remote areas and the impact of these in areas
where glaciers are present; litter and noise. (4 marks)
June 09