1. Plate Tectonics

2. Oceanic-Oceanic Convergent Fault
Formed by two oceanic plates moving towards each other
Allows magma to come through, forming volcanic islands
Aleutian Islands in Alaska formed through the convergence of the North American and Pacific plates.

3. Oceanic-Continental Convergence
Occurs when oceanic and continental plates move towards each other
The oceanic plates goes under the lighter continental plate
Magma rises from the shattered oceanic plate underneath the continent, causing volcanic mountains
The Cascades are formed by the subduction of the Juan de Fuca plate underneath the westward moving North American plate

4. Continental-Continental Convergence
Occurs when continental plates move towards each other
Since neither plate is heavier, the plates simply push towards each other and neither subducts.
They “crumple” and form mountain ranges at the convergence point
The Appalachian Mountain range are a result of this type of convergence
They are the oldest mountain range in the world- around 480 million years old!!!!

5. Oceanic-Oceanic Divergent
Occurs when two oceanic plates are moving away from each other
New magma flows into the space left by the plates and new seafloor is created
This can be shown by the paleomagnetism on the seafloor showing polar direction over thousands of years
The most famous example of this is the Mid-Atlantic Ridge
Sometimes the ridge grows so much it comes above the water surface, like in Iceland

6. Continental-Continental Divergent
Occurs when two continental plates are pulled apart
They form a rift and often streams develop at the bottom
The African Rift Valley is an example of this

7. Transform Boundary
Transform boundaries are the result of two plates moving past each other but not colliding
The San Andreas Fault is a transform boundary

8. Hot spots
Occurs when hot mantle plumes rise through the lithosphere and form volcanic island chains
As the plate on top moves, the location of the island being formed changes, forming a series of islands
An example of this is Hawaii.