Plate Boundaries
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Transcript Plate Boundaries
Plate Boundaries
Plate Boundaries
Why do we care about plate boundaries?
Plate Boundaries
Volcanoes and earthquakes most often occur where
tectonic plates come together.
At plate boundaries, many other geologic features,
such as mountains and rift valleys, can also occur.
Plate Boundaries
There are three basic
types of plate
boundaries:
1. Divergent
2. Convergent
3. Transform Fault
Boundary
Divergent Boundary
A divergent boundary occurs where two plates move
apart and create a gap between them.
Divergent Boundary
Hot rock rises from asthenosphere and cools to form
new lithospheric rock.
Diverging plates then pull newly formed lithosphere
away from gap.
New lithospheric (oceanic crust) is formed.
Divergent Boundary
Mid-oceanic ridges are mountain ranges at divergent
boundaries in oceanic crust.
Divergent Boundary
Real Life Example:
Mid-Atlantic Ridge
Mid-Atlantic Ridge
runs through Atlantic
Ocean from Arctic
Ocean to an area off
the southern tip of
South America.
Convergent Boundary
A convergent boundary
occurs where two plates
move toward one
another.
Convergent Boundaries
There are two types of convergent boundaries:
1. Subduction
2. Collision
Convergent Boundary - Subduction
Subduction is the process by which one lithospheric
plate moves beneath another plate.
Convergent Boundary - Subduction
Ocean – Ocean
Two oceanic plates
collide
Generates volcanoes
Generates island chains
Real World Example
Japan
Convergent Boundary - Subduction
Ocean – Continent
Oceanic and continental
plate collide
A thin, dense oceanic plate
collides with a relatively
light, thick continental
plate, the oceanic plate is
forced under the
continental plate
Real World Example
Andes Mountains
Convergent Boundary - Collision
Continental –
Continental
Two continental
plates collide
Real World Example
Himalayas
Transform Fault Boundary
A transform fault boundary occurs where two plates
slide past one another.
Transform Fault Boundary
Plate movement at
transform fault
boundaries is one
cause of
earthquakes.
Real World
Example
San Andreas Fault
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