Plate Tectonics
Plate Tectonics
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The crust is broken into plates that
float on the mantle.
Sometimes the plates move toward
and under each other and sometimes
they move away from each other.
Plate Tectonics is the theory that
describes the formation, movements
and interactions of these plates.
The world in pieces
Movement of plates
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The movement of
plates causes
• Earth quakes
• Volcanoes
• Mountains
• Trenches
• Mid-ocean ridges
• Rift Valleys
3 Types of Plate Boundaries
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Convergent (moving together)
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Divergent (moving apart)
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Transform (moving side to side)
Convergent Boundaries
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Plates are moving
towards each other
Plates collide and
the denser plate
(oceanic) goes
under the other
(continental) called
SUBDUCTION
Volcanoes,
mountains, and
earthquakes occur
at Convergent
Crust
Boundaries
is destroyed
3 types of convergent boundaries
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Continental-Oceanic
ex. Andes
Continental-Continental
ex. Himalayas
Oceanic-Oceanic
Ex. mid-ocean trenches
like Marianas Trench and
Island Volcanoes like the
Philippines and Japan
Divergent Boundary
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Where new crust is
created as the
plates move away
from each other.
The best known of
the divergent
boundaries is the
Mid-Atlantic Ridge
Forms Rift Valleys
on land and Ocean
Ridges under water
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Plates spread apart
Creates new crust (called
GROWTH MATERIAL)
Transform boundaries
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Two plates move
past each other,
side to side
They cause
earthquakes and
create faults
Ex. The San
Andreas fault zone,
which is about
800miles long