Convergent boundaries: where two plates are colliding. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. The denser plate is Where oceanic crust meets continental crust. The denser oceanic. Tectonic plate interactions are of three different basic types: Divergent boundaries are areas where plates move away from each other, forming either mid-oceanic ridges or rift valleys. These are also known as constructive boundaries. Convergent boundaries are areas where plates move toward each other and Transform boundaries occur when two plates grind past each other. Covers convergent plate boundaries and oceanic plate subduction. of convergent plate boundary is found where two oceanic plates meet.
Convergent Boundary, Where Crustal Plates Collide
Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries in zones that may be anything from a few kilometres to a few hundred kilometres wide. To watch a simulated fly-by along New Zealand's plate boundary check out this video. There are three main types of plate boundaries: Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust.
The denser plate is subducted underneath the less dense plate. The plate being forced under is eventually melted and destroyed. Where oceanic crust meets ocean crust Island arcs and oceanic trenches occur when both of the plates are made of oceanic crust.
Zones of active seafloor spreading can also occur behind the island arc, known as back-arc basins.
This, in turn, makes the base of the crust melt, forming magma. The magma formed at a subduction zone rises up toward the earth's surface and builds up in magma chambers, where it feeds and creates volcanoes on the overriding plate.
When this magma finds its way to the surface through a vent in the crust, the volcano erupts, expelling lava and ash. An example of this is the band of active volcanoes that encircle the Pacific Ocean, often referred to as the Ring of Fire.
List of tectonic plate interactions
Illustration depicting how island arcs are formed. A subduction zone is also generated when two oceanic plates collide — the older plate is forced under the younger one — and it leads to the formation of chains of volcanic islands known as island arcs.
Since the collision and subduction of plates is not a smooth process, large, powerful earthquakes are another phenomenon that result from this type of interaction.
Earthquakes generated in a subduction zone can also give rise to tsunamis.
Interactives . Dynamic Earth . Slip, Slide, & Collide
If a magma chamber rises to the surface without solidifying, the magma will break through in the form of a volcanic eruption. The Washington-Oregon coastline of the United States is an example of this type of convergent plate boundary. Here the Juan de Fuca oceanic plate is subducting beneath the westward-moving North American continental plate. The Cascade Mountain Range is a line of volcanoes above the melting oceanic plate. The Andes Mountain Range of western South America is another example of a convergent boundary between an oceanic and continental plate.
Here the Nazca Plate is subducting beneath the South American plate.
Visit the Interactive Plate Boundary Map to explore satellite images of convergent boundaries between oceanic and continental plates. Two locations are marked to show this type of plate boundary - the Cascade volcanoes along the Washington-Oregon coast of North America and the Andes mountain range on the western margin of South America. Effects of a convergent boundary between an oceanic and continental plate include: Convergent Plate Boundary - Oceanic When a convergent boundary occurs between two oceanic plates, one of those plates will subduct beneath the other.
- Slip, Slide, & Collide
- Tectonic Plates and Plate Boundaries
- Convergent Plate Boundaries
Normally the older plate will subduct because of its higher density. The subducting plate is heated as it is forced deeper into the mantle, and at a depth of about miles km the plate begins to melt.
Magma chambers are produced as a result of this melting, and the magma is lower in density than the surrounding rock material.