Why do oceanic plates slide under continental plates?

Answer 1

Oceanic plates are basaltic and denser than granitic continental rocks.  The denser rock tends to slide under the lighter rock.

Answer 2

When two plates collide (at a convergent plate boundary), some crust is destroyed in the impact and the plates become smaller. The results differ, depending upon what types of plates are involved.


---> Oceanic Plate and Continental Plate - When a thin, dense oceanic plate collides with a relatively light, thick continental plate, the oceanic plate is forced under the continental plate; this phenomenon is called subduction. <---


.