Download Plate Tectonics

Plate
Tectonics
Mrs. Chamberlain’s 7th
Grade Science
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The top layer of the Earth's
surface is called the crust (it lies
on top of the plates).
There is an upper mantle which
includes the asthenosphere
and a lower mantle.
The crust and the upper mantle
are called the lithosphere.
Convection currents (in
asthenosphere) drive the
motion of the tectonic plates.
This occurs due to heat from
the core.
Boundaries
Convection Currents
Demonstration
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The Eurasian plate, Australian-Indian plate, Philippine
plate, Pacific plate, Juan de Fuca plate, Nazca plate,
Cocos plate, North American plate, Caribbean plate,
South American plate, African plate, Arabian plate, the
Antarctic plate, and the Scotia plate.
Pangaea
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In 1915, the German geologist and meteorologist Alfred
Wegener (1880-1930) first proposed the theory of continental
drift
Continental drift states that parts of the Earth's crust slowly drift
atop a liquid core.
The fossil record supports the theories of continental drift and
plate tectonics.
Layers of
the Earth
Bibliography
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Wegener hypothesized that there was an original,
gigantic supercontinent 200 million years ago, which he
named Pangaea, meaning "All-earth".
Pangaea was a supercontinent consisting of all of Earth's
land masses.
Continental
Drift
Bibliography
Divergent
Boundaries
(divide)
Convergent
Boundaries
Transform
Boundaries
(collide)
(slide)
Plate
Boundaries
Continental Drift
Two plates moving apart from
each other
 Where the plates move away from
each other is called the zone of
divergence
 Description/Example: Sea-floor
spreading (Mid-Atlantic Ridge),
Rift valleys (Great Rift Valley)
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When two plates collide.
Description/Examples: cont/cont = mountains; cont/ocean
– volcanoes; ocean/ocean – subduction zone (&
volcanoes)
Subduction is when an oceanic plate collides with an
continental plate and is forced under it.
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When two plates move sideways against each
other
Can cause lots of friction and is jerky
Description/Examples: Faulting (cracks and
earthquakes); force is shearing
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When two plates collide and one slides under the other
the region below is called the subduction zone.
Description/Examples: Cont/ocean – ocean sinks below;
ocean/ocean – one sinks; either can form volcano
Bibliography
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Earth’s Continental Plates,
http://www.enchantedlearning.com/subjects/astronomy/planets/earth/
Continents.shtml
Continental Drift Picture 1,
http://www3.bc.sympatico.ca/Moon/earths.gif
Pangaea Picture,
http://www.mun.ca/biology/scarr/139412_Pangaea_rotated.jpg