Earth Science

Plate Tectonics

Convergent Plate Boundaries

Study Tip
Make a chart of the three kinds of convergent plate boundaries, discussing the geological formations that come out of these converging plate boundaries.

Oceanic-Continent Convergence

Oceanic-continent convergence: When the two different types of plates converge, subduction occurs where the denser oceanic plate goes beneath the continental plate. The entire region of subduction is called the subduction zone. The subducting oceanic plate causes melting in the Earth’s mantle, creating volcanoes. The resulting volcanoes are known as the continental arc. Felsic (viscous) magma at a continental arc cools to form large structures of igneous rock called batholiths, which may eventually become mountain ranges.

Study Tip
Make a chart of the three kinds of convergent plate boundaries, discussing the geological formations that come out of these converging plate boundaries.
Study Tip
The same way a person may cast a shadow over another person when they stand under the sun, planets or celestial bodies that have aligned themselves cast shadows over one another as well.

Oceanic-Oceanic Convergence

Oceanic-oceanic convergence: This type of convergence also results in subduction and subduction zones. These subduction zones create continental arcs known as island arcs. Subduction zones that are no longer active are ocean trenches. These trenches mark the place where an ocean plate is pushed down. The plate that gets pushed up forms volcanoes. When these volcanoes erupt, islands form.

subduction of the Pacific plate
The subduction of the Pacific plate beneath the North American plate created the Cascade Range, a continental arc. The Juan de Fuca plate resulted from seafloor spreading

Continental-Continental Convergence

Continental-continental convergence: Continental crust is too buoyant to subduct, therefore when two continental plates collide they go up, forming mountain ranges. The stress the two plates experience form many metamorphic rocks. Because of the stress, earthquakes are also common in areas where there are a lot of mountains.

two continental plates collide
Notice how the continental crust goes up as two continental plates collide.
Concept Check
  • What is oceanic-continent convergence? Oceanic-oceanic convergence? Continental-continental convergence?
  • What is subduction? A subduction zone?
  • What are continental arcs? How do they form?
  • What are batholiths? How do they form?

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