- Plate Tectonics means that the earth is made up of large, moving plates of solid rock.
Separating Plates
As two plates separate, magma wells up to fill the space between. The magma cools and becomes solid, which forms a new crust. For example, The Mid Atlantic Ridge, here, the North American and Eurasian plates are pulling apart.
Colliding Plates
When plates collide, the crust is destroyed, when an oceanic plate collides with a continental plate, the heavier oceanic plate is forced under the lighter continental plate and down into the hot mantle below, causing part of the melt and part of the continental plate to buckle. These processes form fold mountains and volcanic mountains. An example of this is where the Nazca and South American plate to collide.
Sliding Plates
As two plate slide past each other, their edges sometimes become locked together. As the pressure builds up one plate may snap or jolt forward suddenly, causing earthquakes. For Example, the San Andreas Fault in North America which is caused by the sliding of the Pacific and American Plates