Plate Tectonics
The Earth’s Crust in Motion…
The Theory
In 1910 Alfred begins to wonder…
What’s the relationship?
Perhaps all these pieces used to be connected.
Continental drift=slow movement over Earth’s surface
300 million years ago…
Supercontinent
Pangea – all lands
•Reptiles and insects
•Tropical forrests
-coal deposits
Tens of Millions of years!
Structure of the Earth’s Interior
How does it work?
Plates – pieces of the lithosphere
Plates fit closely together along
cracks called
Plate Boundaries
Convection Currents  movement
Earth’s Puzzle
• What plate do we live on?
• What plates do we border?
• USGS Earth’s Plates
• How far do we move every year?
Types of Boundaries
• Divergent
• Convergent
• Transform
Your Task...Get Organized
• Get into teams of three
• Each person will focus on one type of
boundary
– divergent (Column A)
– convergent (Column B)
– transform (Column C)
• Look only at your column
• Make a concept map
A
Divergent
•plates are
moving apart
•new crust is
created
•Magma is
coming to the
surface
B
Convergent
•plates are coming
together
•crust is returning
to the mantle
C
Transform
•plates are
slipping past
each other
•crust is not
created or
destroyed
A
Divergent
Continental crust
 rift valley
B
Convergent
2 continental plates 
mountain range
C
Transform
Plates move
against each
other
Stress builds up
Oceanic crust  midocean ridge
2 oceanic plates or
oceanic + continental
subduction
Stress is released
earthquake
The Big Picture
Key Terms for Map
convergent boundary
divergent boundary
transform boundary
subduction
rift valley
mid-ocean ridge
continental crust
oceanic crust
mountain range
earthquake