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Plate Tectonics
Chapter 4.5
• Who is J.
Tuzo Wilson
and what
was his
idea?
• J.Tuzo Wilson proposed that all the
lithosphere is broken into separate
sections called plates. His idea lead
to the current theory of Plate
tectonics.
• What is the
theory of
Plate
Tectonics?
• The Theory of Plate Tectonics
states that pieces of Earth’s
lithosphere are in constant, slow
motion, driven by convection
currents in the mantle. The
theory explains the formation,
movement, and subduction of
Earth’s Plates.
» Map with boundaries
» Plate tectonic video
• Three Kinds of Plate
Boundaries:
• Describe and • 1) Transform Boundaries
draw the three • Two plates slip past each other,
types of plate
moving in opposite directions.
boundaries.
Earthquakes often happen at this
kind of boundary.
• Transform boundary animation
• Plate tectonic video
• 2) Divergent Boundaries
• Two plates move apart. Most
happen at the mid-ocean ridge.
Rift valleys are a kind of
divergent boundary that forms on
land.
Divergent plate boundary animation.
Rift valley animation
Plate tectonic video
Rift Valley
•
•
Convergent Boundaries
Two plates come together.
When two plates converge, or
come together, a collision
happens.
•
Convergent Plate Boundary
• What are the
three types of
convergent
boundaries.
What happens
at each type.
• Three types of convergent boundaries
• A.) Oceanic crust – Ocean crust
– The plate more dense dives under the
other plate. SUBDUCTION
• B) Oceanic Crust – Continental Crust
– The less dense continental crust can’t sink
under the denser O.C., so the O.C.
plunges beneath the C.C. SUBDUCTION
• C) Continental Crust – Continental
Crust
– Subduction doesn’t happen. Instead the
plates crash head-on and form mountain
Ranges. MOUNTAINS
– c.c. colliding with c.c.video
•
•
•
•
Animation of all three plate boundaries.
Animation of all three types.
Plate tectonic video
Bill Nye Plate tectonics Video Bill Nye.asf
A.______________________________
B.______________________________
C.______________________________
• What causes
the plates to
move?
• Pacific Ocean is getting smaller
and the Atlantic Ocean is getting
wider due to seafloor spreading
and subduction.