Do oceanic plates subduct?

Do oceanic plates subduct?

When two tectonic plates collide, a subduction zone forms if one or both of the plates is oceanic lithosphere. An oceanic plate will re-enter the mantle. Remember that at midocean ridges, oceanic plates are formed from mantle material. Thus, they too must eventually be returned to the mantle.

Subduction zones form where two plates converge. One plate goes down into the mantle, while the other plate rises up over its neighbor. Subduction zones occur at convergent boundaries between two plates. These can be either continental plates (which have been pushed together vertically by tectonics) or oceanic plates (which have been pulled toward each other horizontally).

It all began with the first observations of volcanoes and earthquakes near modern-day Tokyo made in 1811 by British sailors on board a ship called "Shimpanzee". They observed the new island rising due to volcanic activity and noted that it was being dragged beneath the sea surface by a new type of earthquake activity now known as "subduction".

Since then, scientists have learned that subduction is a major force behind creation of islands and ocean trenches around the world. It also plays an important role in determining the appearance of our planet's surface. For example, subduction causes the formation of the Hawaiian Islands by consuming part of the leading edge of the Pacific Plate under the North American Plate.

What happens when tectonic plates subduct?

When a tectonic plate's oceanic lithosphere collides with the less dense lithosphere of another plate, the heavier plate dives beneath the second plate and descends into the mantle. This process happens in an area known as a subduction zone, and its surface manifestation is known as an arc-trench complex. The trench forms as the descending plate pulls the surrounding crust with it, deepening the intrusion and creating a valley. As the plate moves deeper into the mantle it melts, producing the volcanic arcs that pepper its upper surface.

Subduction occurs at many locations around the world, but it is most prevalent in the Pacific Ocean where two large plates converge. The leading edge of the Pacific Plate plunges beneath Japan and then underneath South America, while the trailing edge underlies North America.

The Philippine Sea Plate also engages in subduction, but it does not reach as far south as Asia because it is being overridden by another plate: the Sunda Plate. The result is that the Philippine Sea Plate rises above the surface of Earth's mantle, causing volcanoes to erupt all over the Philippines and other parts of Southeast Asia.

Subduction is one of the main forces behind the formation of continents and oceans. It plays an important role in generating seismic activity, delivering powerful earthquakes, and may even have contributed to the extinction of some dinosaurs.

What forms in the ocean when an oceanic plate is forced beneath another plate?

When one oceanic plate is driven beneath another, a subduction zone forms. The descending plate melts at the bottom of the trench and raises up new rock that was once far below the surface. This new rock is called "slate". The remaining part of the old oceanic plate is called "ductile rocks". It tends to be flat or gently sloping.

The result is that you have two types of terrain associated with subduction zones: the steep-sided trenches where the plates meet; and the more gradual slopes on either side of the trench. Trenches can reach depths of nearly 5km (3 miles) or more and run for hundreds of kilometers. Slopes often rise only a few meters per kilometer but they extend over very large areas: the Pacific Northwest from Canada to Chile has been formed by subduction erosion of rocks derived from several different sources.

Subduction zones are found everywhere that there are oceans. They form the Andaman Islands off India, the Sunda Shelf off Indonesia, the Kaikoura Ridge in New Zealand, and the Diablo Range in California.

In addition to these obvious examples, many other islands in the world were probably also created by subduction erosion.

About Article Author

Romeo Crouchet

Romeo Crouchet is a dedicated teacher with an eye for detail. He has taught at the college level in both the United States and Canada, and he uses his experience to tailor individualized courses that help students meet their goals. Romeo also enjoys teaching online courses because it enables him to reach more people than ever before.

Disclaimer

BartlesVilleSchools.org is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

Related posts