Why oceanic plates subduct

Oceanic-continental plate collision, subduction and formation of a volcanic arc. Explosive fragmentation of sticky, gas-rich magma erupted at Krakatau volcano, a typical subduction-zone volcano. Try our free app! Android iOS version. Continental rifts. Divergent plate boundaries on continents Learn about the process of breaking up continents along continental rift zones. When two oceanic plates converge, the denser plate will end up sinking below the less dense plate, leading to the formation of an oceanic subduction zone.

When an oceanic plate converges with a continental plate, the oceanic crust will always subduct under the continental crust; this is because oceanic crust is naturally denser. Convergent boundaries are commonly associated with larger earthquakes and higher volcanic activity.

This melting leads to heat being transferred upwards and uplifting the crust, eventually developing into a volcano.

Subduction zones are the reason why oceanic crust older than million years old cannot be found. The enormous forces acting during subduction are periodically expressed by great earthquakes. Volcanic and sedimentary material scraped off the descending oceanic plate accumulates along the leading edge of the overriding plate as an accretionary prism and is eventually incorporated into the adjacent plate margin as a microplate or accreted terrane.

Futhermore, when the subducting oceanic plate reaches a depth of about kilometers, partial melting of the water-rich oceanic crust and some of the overlying mantle takes place. The newly formed magma created in this manner is less dense than the surrounding mantle rocks and will consequently slowly rise when sufficient quantities of molten rock have gathered. It only takes a minute to sign up. Connect and share knowledge within a single location that is structured and easy to search.

It is well known that oceanic plates subduct under continental plates. This may be attributed to the plate's age and density, plus the water on top of it. So I was wondering if it is ever possible for a continental plate to subduct under an oceanic plate, perhaps if the oceanic plate is covered with shallow water? I've tried to search up on this question on many search engines and sites but to no avail. Thanks for your answer! No it is not possible because the continental crust's density is lower.

Conversely, oceanic plates can subduce under continental ones because they are heavier. This is because continental crusts are formed by granites and sedimentary materials. Oceanic plates start to subduce at a certain age. Presently there are not pre-Jurassic oceanic plates that do it.

This is related with the stack of hidrated sediments over the igneous materials. An exception to this are ophiolites , where oceanic plate obduce continental one. This is not happening presently at any place on Earth, but there are fossilized examples as Semail Ophiolite at Oman.