Convergent boundaries
Called convergent boundaries, where the collision of plates. There are three options:
1. Continental plates in the ocean. Oceanic crust is denser than continental and sinks beneath the continent at a subduction zone.
2. Oceanic plate with the ocean. In this case, one of the plates crawls under the other, and also formed subduction zone, over which formed an island arc.
3. Continental plate with continental. There is a conflict, there is a strong orogen. A classic example - the Himalayas.
In rare cases there is the thrusting of the oceanic crust to continental - Obduction. Through this process have ophiolites of Cyprus, New Caledonia, Oman and others.
In subduction zones oceanic crust is absorbed, and thus compensated for its appearance in the mid-ocean ridges. They are extremely complex processes, the interaction of crust and mantle. Thus the oceanic crust may drag into the mantle blocks of continental crust, which, because of low density exhumes back to the cortex. This gives rise to ultrahigh-pressure metamorphic complexes, one of the most popular objects of modern geological research.
Most of today's subduction zones are located on the periphery of the Pacific Ocean, forming the Pacific Ring of Fire. Processes in the zone konvegentsii plates, is considered to be among the most complex in geology. There are mixed blocks of different origin, forming a new continental crust.