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Plate Tectonics
8th Grade Science
With the marvelous Mr. Christine
What is Plate Tectonics?
• Remember what a theory was?
– A scientific Theory is a well tested concept that explains
many observations.
• So, the Theory of Plate Tectonics is …
– Pieces of the Earth’s Lithosphere are in slow, constant
motion, driven by convection currents in the mantle.
Remember the Interior of the Earth or
else …
What a full plate
What is a plate?
• A plate is a section of the lithosphere that
slowly moves over the asthenosphere,
carrying pieces of oceanic and continental
crust.
Remember Convection
• The transfer of heat by movement of a fluid.
• This causes plate movement
Plate Boundaries
• The Earth is broken up into many plates
• So, the plates meet at areas called
boundaries
• Plate Boundaries: Where edges of
world’s plates meet.
• 3 types
– Divergent, Convergent, and Transform
Divergent Boundary
• Divergent Boundary: Place where two plates
move apart or diverge.
• Ocean = Mid Ocean Ridge
• Land = Rift Valley
Divergent Boundary
Convergent Boundary
• Convergent Boundary: Place where two
plates come together or converge and
collide.
• Remember Subduction?
Convergent Boundary
Transform Boundary
• Transform Boundary: Place where two
plates slip past each other moving in
opposite directions.
• Earthquakes occur but no crust is
destroyed
San Andreas Fault (Transform)
All Boundaries
Pangea to Future