What is Plate Tectonics? 8.1
Plate Tectonics-
 A lithospheric plate moves as a unit, “floating” on top of the asthenosphere

Early Ideas About Plate Movement
Alfred Wagener (German Scientist 1900’s)-
Continental Drift-
Weagener was not successful
1.
He found similarities in the shapes of continents in that they would
“fit” together as one large continent
2.
The Theory of Plate Tectonics-
-Data showed that earthquakes and volcanoes do not occur
randomly throughout the world but at specific boundaries

Types of Plate Boundaries- 8.2
There are three main types of plate boundaries
1.
Divergent boundaries-
-Run along ocean floors and have rift valleys (deep
valleys)
-
2.
Convergent Boundaries-
Two Types of Convergent Boundaries
1.
Subduction Boundary-
-
2.
Collision Boundary-
-
3.
Transform Boundaries-
Ex. San Andreas Fault
8.4 Plate Movements and Continental Growth
Pangaea-
Pangaea broke apart into two pieces
1.
Laurasia-
2.
Gondwana-

*What happens where plates meet?
1.
Divergent Boundary- plates move away from each other.
New crust is being created.
2.
Convergent Boundary-two plates come together, or collide.
Crust material is being destroyed.
3.
Transform Boundary- two plates slide in opposite directions beside each other (San Andreas Fault)
*Three kinds of convergent boundaries
1.
Ocean-Ocean – One plate is pushed down under the other
Trenches (deepest part of an ocean) and volcanoes form
2.
Ocean-Continent- Ocean plate is subducted and a mountain range forms usually containing volcanoes.
3.
Continent-Continent- Because both plates are similar they compress and form tall mountains