Download Plate Boundaries

Unit 3: Plate Boundaries
• Lesson Objectives:
• To understand what
occurs at different plate
boundaries.
Plate 1
• Success Criteria:
• Create an annotated
diagram of each plate
boundary.
Plate 2
Continental crust
THE WORLD’S MAIN PLATE
BOUNDARIES
2
5
5
3
5
3
2
5
17
10
3
2
5
7
18
1
7
18
4
1
3
2
key
Plates
Earthquake foci
Constructive margin
Collision zone
Destructive zones
Movement of plates
Uncertain plate boundary
A Adriatic
B Aegean
C Turkish
D Juan de Fuca
E Cocos
6 Rate of movement
(cm per year)
2
Starter: Name the plate boundaries.
There is a
relationship between
plate boundaries and
tectonic activity.
EARTHQUAKES
ACTIVE VOLCANOES (shown as
red dots)
PLATE BOUNDARY
Constructive
(spreading or
divergent) margins
Volcanoes are
found at…
Destructive
(convergent subduction or
collision) margins
Conservative
(passive or
transform) margins
Earthquakes
are found at…
Two oceanic plates are moving away from each other and magma rises to the surface to
create new crust. It forms mid-oceanic ridges such as the Mid Atlantic Ridge. (If this new
material reaches above the ocean it forms land e.g. Iceland.) This activity leads to low
magnitude earthquakes and also volcanoes. Click on the flash button below.
Iceland lies on the plate boundary between the North American and the
Eurasian plates. The island has been created by divergent plate movement.
The photo shows Thingvellir – to the right is the Eurasian plate and to the
left is the North American plate
Plates pulling
apart
In oceanic areas:
e.g. Mid Atlantic Ridge and Iceland
• Mid oceanic ridges and transform faults
• Shield volcanoes e.g. Surtsey
• Shallow focus earthquakes
Iceland
A growing new volcanic island - Surtsey
Surtsey
In continental areas:
• Rift valleys
In continental areas:
• Volcanoes.
TYPES OF PLATE BOUNDARY
1 Constructive margins
(spreading or divergent plates)
Processes
•
Two plates move apart from each
other.
•
New oceanic crust is formed,
creating mid ocean ridges.
•
Volcanic activity is common.
•
Mid Atlantic Ridge (Europe is
moving away from North America).
Divergent margin
Plate 1
2 Destructive margin
(subduction zone)
Processes
• The oceanic crust moves towards
the continental crust and sinks
beneath it due to its greater
density.
• Deep sea trenches and island
arcs are formed.
• Volcanic activity is common.
• Example: Nazca sinks under the
South American plate.
Convergent margin (subduction)
Plate 1
Plate 2
Oceanic crust
Mid-ocean ridge
Rift valley
Oceanic trench
Oceanic crust
Lithosphere
Asthenosphere
Asthenosphere
Plate 2
Continental crust
When an oceanic plate moves towards a continental plate (subduction):
• Deep sea trenches
• Fold mountains -The Andes
• Explosive volcanoes
• Earthquakes (shallow,
intermediate and deep)
When 2 oceanic plates move toward each
other the following are formed:
Nevado del Ruiz in Colombia
• oceanic trenches
• island arcs e.g. Japan
• explosive volcanoes
• earthquakes
TYPES OF PLATE BOUNDARY
(CONTINUED)
3 Collision zones
Processes
• Two continental crusts collide.
• As neither can sink they are
folded up into fold mountains.
• Example: The Indian plate
collided with the Eurasian plate to
form the Himalayas.
Convergent margin (collision)
4 Conservative margins (passive
margins or transform plates)
Processes
• Two plates move sideways past
each other but land is neither
destroyed nor created.
• Example: San Andreas fault in
California.
Transform fault margin
Plate 1
Plate 1
Transform fault
Continental crust
Lithosphere
Lithosphere
Asthenosphere
Plate 2
Plate 2
Asthenosphere
Continental crust
At a collision margin two continental crusts collide. As neither can sink they
are folded up into fold mountains. The Himalayas is an example of this,
formed as India collided with the Eurasian plate.
Plate 1
Plate 2
Continental crust
Shallow focus earthquakes are
frequent along these boundaries
Task: Draw annotated diagrams of
each plate boundary on a revision
card. Include an example of each one.
Plate
1
Plate 2
Continental crust
Divergent margin
Plate 1
Oceanic crust
Rift
valley
Plate 2
Mid-ocean
ridge
Lithosph
ere
Asthenosph
ere
Oceanic
crust
Convergent margin
Plate 1
Plate 2
(subduction)
Continental
Oceanic
trench
Asthenosph
ere
crust
Unit 3: Plate Boundaries
• Lesson Objectives:
• To understand what
occurs at different plate
boundaries.
Plate 1
• Success Criteria:
• Create an annotated
diagram of each plate
boundary.
Plate 2
Continental crust
Plenary
In groups of four develop a group mime to show
what happens at a Constructive or a
destructive plate boundary.