Transcript Plate Tectonics Powerpoint by M.A. Garcia

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
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
convergent boundary
divergent boundary
transform boundary
subduction
rift valley
mid-ocean ridge
continental crust
oceanic crust
mountain range
earthquake