A convergent boundary is a tectonic plate boundary where two lithospheric plates move toward each other and collide. This collision can cause one plate to slide beneath the other in a process called subduction, or if both plates are of similar density, they may push up against each other without subducting. Convergent boundaries are also known as destructive boundaries because they often result in the destruction of lithosphere
. There are three main types of convergent boundaries based on the types of crust involved:
- Oceanic-Continental: The denser oceanic plate subducts beneath the less dense continental plate, leading to volcanic activity and the formation of mountain ranges and deep ocean trenches. Magma generated by melting in the mantle rises to form volcanoes parallel to the boundary. Earthquakes are common here. An example is the Nazca Plate subducting beneath the South American Plate, forming the Andes Mountains and the Atacama Trench
- Oceanic-Oceanic: One oceanic plate subducts beneath another, creating volcanic island arcs and deep trenches. The denser, usually older, oceanic crust subducts beneath the younger one. An example is the Aleutian Islands formed by the Pacific Plate subducting beneath the North American Plate
- Continental-Continental: When two continental plates collide, neither subducts due to their buoyancy. Instead, they crumple and fold, forming large mountain ranges such as the Himalayas formed by the collision of the Indian and Eurasian Plates
Convergent boundaries are associated with significant geological activity including earthquakes, volcanism, mountain building (orogenesis), and the formation of deep ocean trenches. They play a key role in the recycling of Earth's lithosphere through subduction and are driven by mantle convection processes
. In summary, a convergent boundary is where tectonic plates move toward each other, resulting in collision or subduction, which shapes many of Earth's major geological features.
