Plate Tectonics

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.

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

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!!!!

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

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

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

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.