There are three types of tectonic plate boundaries. When two plates slide past each other, they form a boundary. A boundary occurs when two plates pull away from each other. When two plates collide with each other, they form a boundary.
The three types of tectonic plate boundaries are:
1. Transform Boundaries: This type of boundary occurs when two plates slide past each other horizontally. As the plates move in opposite directions, they can get locked and build up stress. When the stress is released, it results in an earthquake. The San Andreas Fault in California is an example of a transform boundary.
2. Divergent Boundaries: These boundaries occur when two plates move away from each other. As they separate, new crust is formed from molten material rising to fill the gap. This process creates a mid-ocean ridge, where new oceanic crust is continuously created. The East African Rift Valley is an example of a divergent boundary.
3. Convergent Boundaries: This type of boundary occurs when two plates collide with each other. There are three subtypes of convergent boundaries, based on the types of plates involved:
- Oceanic-Continental Convergence: When an oceanic plate collides with a continental plate, the denser oceanic plate usually subducts beneath the continental plate, forming a deep ocean trench. This process can lead to volcanic activity and the formation of mountain ranges. The Andes Mountains in South America are an example of an oceanic-continental convergent boundary.
- Oceanic-Oceanic Convergence: When two oceanic plates collide, one of them usually subducts beneath the other. This subduction can result in the formation of island arcs, which are volcanic chains. The Aleutian Islands in Alaska are an example of an oceanic-oceanic convergent boundary.
- Continental-Continental Convergence: When two continental plates collide, neither can be subducted due to their low density. Instead, the collision causes the crust to compress and fold, leading to the formation of massive mountain ranges. The Himalayas in Asia are an example of a continental-continental convergent boundary.