Transcript Don’t Break Your Plate

Don’t Break Your Plate
Notes on Plate Tectonics
Key Points

Plate tectonics accounts for several
features on the earth’s surface
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Seafloor spreading
Subduction zones
Earthquakes
Volcanoes
Mountain ranges
Plates move due to mantle convection
How do plates move?
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The plates of the Earth float on top of the
aesthenosphere
When mantle rock near the Earth’s core
heats up it becomes less dense and rises
while the cooler rock near the surface
sinks—mantle convection
Moves plates a few centimeters each year
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http://www.classzone.com/books/earth_science/
terc/content/visualizations/es0804/es0804page0
1.cfm?chapter_no=visualization
Three types of plate boundaries:
1.
2.
3.
Divergent
Transform
Convergent
Divergent Boundaries
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New crust is created as
two plates pull away
from each other
If two oceanic plates,
the ocean will grow
wider—seafloor
spreading
If two continental
plates, creates a rift
that will form two
different land masses
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Fills with water in the
rift
Transform Boundaries
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Two plates are sliding
horizontally past one
another
Sometimes known as
faults
Earthquakes take
place along these
boundaries
Convergent
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There are 3 types of convergent
boundaries:
1.
2.
3.
Oceanic-oceanic convergence
Continental-continental convergence
Oceanic-continental convergence
 Crust is destroyed and recycled back into
the Earth’s interior as one plate sinks
below another plate—subduction zones
 Mountains and volcanoes often form here
Oceanic-Oceanic Convergence
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When one oceanic plate subducts under
another:
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A deep ocean trench is formed
Creates undersea volcanoes that over time, can build
up to form volcanic islands
Continental-Continental
Convergence
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When two continental plates meet head-on,
neither one subducts.
Plates tend to buckle and rise up/sideways to
form mountain ranges
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i.e. Himalayan Mountains
Oceanic-Continental Convergence
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When an oceanic plate subducts below a
continental plate:
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The continental plate rises to form mountains
When oceanic plate sinks deep, some pieces break off
and get locked in place—leads to earthquakes
Which of the following is not a
plate boundary?
25%
1.
2.
3.
4.
25%
25%
2
3
25%
Divergent
Convergent
Transvergent
Transform
20
1
4
Where are mountains and
volcanoes often found?
33%
1.
33%
2.
33%
3.
Subduction Zones
Mid-ocean Ridge
Seafloor Spreading
20 Seconds
Remaining
Which of the following is NOT a
type of convergent boundary?
1.
2.
3.
4.
Ocean-ocean
Continental-ocean
Continentalcontinental
Continental-sea
25%
25%
25%
2
3
25%
20
1
4
This type of boundary is two plates
pulling away from each other to
create new crust.
1.
2.
3.
Convergent
Divergent
Transform
33%
33%
33%
20
1
2
3
This boundary type has two
plates sliding past each other
1.
Convergent
33%
2.
Divergent
33%
3.
Transform
33%
20
This is where one plate sinks
below another, melting back
into the mantle.
1.
2.
3.
4.
Transform
boundary
Subduction zone
Mid-ocean ridge
Divergent
boundary
20
25%
25%
25%
25%
1
2
3
4
How do the tectonic plates move?
1.
2.
3.
Convection
currents in the
mantle
Convection
currents in the
inner core
Conduction in the
mantle
20
33%
1
33%
2
33%
3