Transcript Plate Tectonics

Plate Tectonics
Plate Tectonics
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accepted by the vast majority of scientists
Earth’s interior is made up of two layers: the
lithosphere comprising the crust and the
solidified uppermost part of the mantle.
Mantle is on top of the asthenosphere, a very
thick viscous fluid layer
Lithosphere “floats” on asthenosphere.
Plate Tectonics
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Lithosphere broken into
tectonic plates
10 major and many
minor plates
How Plates Move.
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Convection currents:
heating causes a
material to expand and
rise, then cooling causes
the material to contract
and fall.
Lithosphere on a
metaphorical treadmill.
3 Types of Plate Boundaries
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1. Transform
Boundaries
2. Convergent
Boundaries
3. Divergent
Boundaries
Convergent Boundary
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2 plates moving toward
each other
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Subduction Zone: one
plate slides under
another. Correlated with
volcanoes.
Continental Collision: if
two continental plates
collide. EX: Himalayan
mountains
Transform Boundaries
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Plates grind past each
other.
Fault line
San Andreas
Earthquakes
Divergent Boundary
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2 plates slide away from
each other
Mid-ocean trenches
Key concept supporting
plate tectonics
Pangaea
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Super continent
believed to exist during
prehistoric times.
Breaking up of Pangaea
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First major break up of
Pangaea occurred
during the Triassic
period.
Formation of Atlantic
Ocean and Mississippi
river occurred.
Breaking up of Pangaea
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150 million years ago
South America break
away from super
continent
India and Africa begin
to move north
Breaking up of Pangaea
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60-50 million years ago
North America and
Greenland break away
India collides with Asia
Australia breaks away
from Antarctica