Transcript Plate boudaries

Why do the plates move?
Crust
Convention
Currents
Mantle
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Eurasian
North
American
Pacific
African Plate
Nazca
South
American
Indo Australian
Plate
Antarctic
Plate Names
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Mid-Atlantic ridge
Sea Floor Spreading!
Did you know that the
ocean floor in the
Atlantic is growing by
3cm per year?
Which of the following pairs of continents are moving
further away from each other?
1) Europe and Africa
2) Europe and North America
3) South America and North America
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Constructive
Plate
Boundary
At a constructive plate boundary, two
plates move apart. As the two plates
move apart, magma rises up to fill
the gap. This causes volcanoes at
this type of boundary. However, since
the magma can escape easily at the
surface the volcano does not erupt
with much force. Earthquakes are
also found at constructive
boundaries.
An example of a constructive
boundary is the Mid-Atlantic Ridge.
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A destructive plate boundary is found
where a continental plate meets an
oceanic plate.
Destructive
Plate
Boundary
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The oceanic plate descends under the
continental plate because it is denser.
As the plate descends it starts to melt
due to the friction caused by the
movement between the plates. This
melted plate is now hot, liquid rock
(magma). The magma rises through
the gaps in the continental plate. If it
reaches the surface, the liquid rock
forms a volcano.
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Conservative plate boundaries
exist where two plates do not
directly collide but slide past
each other along a fault
(weakness).
Conservative
Boundary
No volcanoes are found along
these plate boundaries, but
earthquakes do occur.
An example of such a boundary
is the San Andreas Fault in
California.
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Name this plate boundary
A
G
B
E
C
F
D
Match the labels to the letters
Earthquakes occur due to friction
The oceanic crust sinks under
the less dense continental crust
Oceanic plate
Continental crust
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Explosive volcanoes
The oceanic crust
melts and rises
Mantle
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Constructive plate boundaries
MID OCEAN
RIDGE
B
A
Ocean
Mantle
Where would you find older rocks – at A or at B?
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