Download Plate Boundaries

Theory of Plate Tectonics
• Theory that pieces of lithosphere move
around on top of the asthenosphere
Plate Boundaries
• The edges of
different pieces of
The lithosphere
meet at lines
called plate
boundaries
Plate Boundaries
Plate Videos
So the plates move.
Now What?
•As the plates move,
they produce changes
in Earth’s surface,
including volcanoes,
earthquakes, mountain
ranges, and deepocean trenches.
3 Types of Plate Boundaries
Divergent
Convergent
Transform
Transform
Divergent
3 Types of Boundaries
Divergent boundary= two plates move
apart
• Magma rises and creates new crust
or seafloor
Causes: midocean ridges,
rift valleys,
new crust ,
volcanoes
Divergent Boundaries
© All Rights Reserved.
Diverging Africa
Diverging Iceland
3 Types of Boundaries
• Convergent= when two tectonic
plates push into one another.
Convergent Boundaries
• Continental vs. Continental
• Continental vs. Oceanic
• Oceanic vs. Oceanic
Continental vs. Continental
•When two continental
crustal plates collide,
the continents buckle
upward and form
mountains.
Himalayas- Asia
Himalayas- Asia
Oceanic vs. Continental
•The oceanic plate
slides under the
continental plate.
•The continental crust
crumbles and forms
new mountains.
Oceanic vs. Continental
• Ex: Andes mtn in S.
America
Cascade Mtns. in N.
America- Mt. St.
Helens
Oceanic vs. Oceanic
•Two oceanic plates
collide, one of the
oceanic plates slides
under the other.
•also called a
subduction zone
Oceanic vs.
Oceanic Hawaiian
Islands
Transform boundary
• When two tectonic plates slide past each
other horizontally
Produces?
Earthquakes
San
Andreas
Fault
New Madrid Fault
How do the plates move?
• CONVECTION CURRENTS
• Hot material rises while
cooler material near the
surface sinks
• Convection example
How do the plates
move?
• CONVECTION CURRENTS
• Hot material from deep within the Earth
rises while cooler material near the
surface sinks
Convection currents
How do we know?
• Sea-floor spreading
=new ocean floor is
created as two
lithospheric plates
pull away from
one another.
Seafloor spreading
The Plates Move…
So what now?
Which way?
• 50 million years