Types of Plate Boundaries
The plates can move next to each other, towards each other, or away from each other. Each of these kinds of movement creates a different type of plate boundary. The picture above and video below shows what these different types of movement look like.
Most divergent boundaries are found in the ocean. The new crust that forms at the boundary is sima, or oceanic crust. It often rises higher than the rest ocean floor, forming an underwater mountain range. This is called a mid-ocean ridge. The plates then continue to move the new seafloor away from the boundary.
Plates move towards each other at convergent boundaries. When an oceanic plate meets a continental or another oceanic plate, subduction occurs. This means that the heavier oceanic plate slides underneath the other plate. The oceanic crust melts when it meets the mantle, forming magma. Volcanoes and oceanic trenches often form at convergent boundaries.
When two continental crusts meet, there is no subduction. The continents’ crust is too light to get pushed down into the earth. Instead, the crust gets pushed up, forming mountain ranges.
At transform boundaries, plates slide past each other. Unlike the other boundaries, the crust isn’t created or destroyed. Instead, the crusts move in opposite directions next to each other. Movement at transform plate boundaries is rarely smooth. As plates move past each other they get stuck on each other. This causes energy to build up. The release of that energy causes an earthquake. The San Andreas Fault is a transform boundary that has caused many earthquakes.
Other Great Resources
Tectonic Plates and Plate Boundaries – GNS Science:
Understanding Plate Motion – USGS: https://pubs.usgs.gov/gip/dynamic/understanding.html
What is Plate Tectonics? – Live Science: https://www.livescience.com/37706-what-is-plate-tectonics.html
BrainPOP Video on Plate Tectonics: