What Happens To Oceanic Crust At A Deep Ocean Trench

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What Happens To Oceanic Crust At A Deep Ocean Trench?

What happens to oceanic crust at a deep-ocean trench? At a deep-ocean trench the oceanic crust bends downward. In a process taking tens of millions of years part of the ocean floor sinks back into the mantle at deep-ocean trenches.

What happens to the old crust when it sinks into the deep ocean trench?

Subduction zones usually associated with deep ocean trenches are found around the world. … As it moves down into the subduction zone our crust is pushed down under another plate. It bends down and starts to sink into the mantle – the older the crust the steeper the angle.

Is ocean crust destroyed at deep sea trenches?

If the oceanic crust reaches a deep sea trench it sinks into the trench and is lost into the mantle. Scientists now know that the oldest crust is coldest and lies deepest in the ocean because it is less buoyant than the hot new crust.

What eventually happens to most oceanic crust?

Oceanic crust slowly moves away from mid-ocean ridges and sites of seafloor spreading. As it moves it becomes cooler more dense and more thick. Eventually older oceanic crust encounters a tectonic boundary with continental crust. In some cases oceanic crust encounters an active plate margin.

What is a deep ocean trench called?

deep-sea trench also called oceanic trench any long narrow steep-sided depression in the ocean bottom in which occur the maximum oceanic depths approximately 7 300 to more than 11 000 metres (24 000 to 36 000 feet). They typically form in locations where one tectonic plate subducts under another.

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What happens when oceanic crust converges with continental crust?

When oceanic crust converges with continental crust the denser oceanic plate plunges beneath the continental plate. This process called subduction occurs at the oceanic trenches (figure 6). … The subducting plate causes melting in the mantle. The magma rises and erupts creating volcanoes.

What causes the sinking of the oceanic crust?

Oceanic crust forms from hot magma rising to Earth’s surface at divergent plate boundaries… … Ocean water can be trapped in ocean crust contributing to its density. Because ocean crust is more dense than continental crust it will sink beneath continents if tectonic forces push the oceanic crust into the continent.

What destroyed at trenches?

Seafloor spreading processes create new oceanic crust at mid-ocean ridges and destroy older crust at deep sea trenches.

What happens when two oceanic plates collide?

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. … Earthquakes generated in a subduction zone can also give rise to tsunamis.

What do deep sea trenches reveal about Earth’s crust?

What do deep-sea trenches reveal about Earth’s crust? They indicate where crust is moving together and diving down deeper into the mantle.

What process results in the ocean floor sinking beneath a deep ocean trench and back into the mantle?

The process by which the ocean floor sinks into the mantle is called Subduction ..

What rock makes up oceanic crust?

basalts

Oceanic crust extending 5-10 kilometers (3-6 kilometers) beneath the ocean floor is mostly composed of different types of basalts. Geologists often refer to the rocks of the oceanic crust as “sima.” Sima stands for silicate and magnesium the most abundant minerals in oceanic crust. (Basalts are a sima rocks.)

What happens to old oceanic crust as new molten material rises from the mantle?

What happens to old oceanic crust as new molten material rises from the mantle? The molten material spreads out pushing older rock to both sides of the ridge.

Why is Marianas trench deep?

The Mariana Trench is part of a global network of deep troughs that cut across the ocean floor. They form when two tectonic plates collide. At the collision point one of the plates dives beneath the other into the Earth’s mantle creating an ocean trench.

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Is there life at the bottom of the Mariana Trench?

The organisms discovered in the Mariana Trench include bacteria crustaceans sea cucumbers octopuses and fishes. In 2014 the deepest living fish at the depth of 8000 meters Mariana snailfish was discovered near Guam. … Fish living closer to the surface of the ocean may have a swim bladder filled with air.

Has anyone been to bottom of Mariana Trench?

On 23 January 1960 two explorers US navy lieutenant Don Walsh and Swiss engineer Jacques Piccard became the first people to dive 11km (seven miles) to the bottom of the Mariana Trench. As a new wave of adventurers gear up to repeat the epic journey Don Walsh tells the BBC about their remarkable deep-sea feat.

What does and oceanic oceanic convergence give rise to?

A volcanic island arc forms in an ocean-ocean plate convergence a volcanic continental arc forms in an ocean-continent convergence.

What is oceanic oceanic convergence?

At an ocean-ocean convergent boundary one of the plates (oceanic crust and lithospheric mantle) is pushed or subducted under the other (Figure 4.6. … It mixes with the overlying mantle and the addition of water to the hot mantle lowers the crust’s melting point and leads to the formation of magma (flux melting).

What is formed when oceanic and continental plates collide?

When an ocean plate collides with another ocean plate or with a plate carrying continents one plate will bend and slide under the other. This process is called subduction. A deep ocean trench forms at this subduction boundary.

When oceanic crust melts it can result in the formation of a?

The oceanic crust melts resulting in the formation of volcanoes. An area in the middle of a continental plate where the plate is beginning to separate. A large valley will form in the area as the crust thins. A crack in the Earth’s crust where rocks slide past one another.

Where is the oceanic crust sinking back into the mantle?

Subduction zones
Subduction zones are where the cold oceanic lithosphere sinks back into the mantle and is recycled. They are found at convergent plate boundaries where the oceanic lithosphere of one plate converges with the less dense lithosphere of another plate.

Does the oceanic plate melt?

Oceanic lithosphere is produced at mid-ocean ridges and reinjected into the mantle at convergent plate boundaries. … At depths of 80-120 km water release by the slab is believed to lead to partial melting of the oceanic crust.

How is an oceanic trench formed?

In particular ocean trenches are a feature of convergent plate boundaries where two or more tectonic plates meet. At many convergent plate boundaries dense lithosphere melts or slides beneath less-dense lithosphere in a process called subduction creating a trench.

What theory explains how new ocean crust is formed at ocean ridges and destroyed at deep ocean trenches?

7. Seafloor spreading: Hess’s theory that new ocean crust is formed at mid-ocean ridges and destroyed at deep-sea trenches occurs in a continuous cycle of magma intrusion and spreading.

What is trench crust?

Trenches are formed by subduction a geophysical process in which two or more of Earth’s tectonic plates converge and the older denser plate is pushed beneath the lighter plate and deep into the mantle causing the seafloor and outermost crust (the lithosphere) to bend and form a steep V-shaped depression.

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What happens when two oceanic plates collide quizlet?

When two oceanic plates collide the denser plate is subducted and some material rises upward and forms an ISLAND. … Ocean floor is pushed away from a midocean ridge to form new sea floor.

Why are most oceanic trenches in the Pacific?

Why are most oceanic trenches found in the Pacific Ocean? The Pacific Ocean is shrinking and plates are descending below surrounding plates along its edges hence the creation of trenches.

How many oceanic trenches are found in the Indian Ocean?

These troughs extend to great depths and in the Indian Ocean there are two particularly deep trenches: the Java Trench and the Diamantina Trench.

How are oceanic ridges and deep ocean trenches related to plate tectonics?

How are mid ocean ridges and deep ocean trenches related to plate tectonics? … Mid-ocean ridges are spreading centers that is they are divergent plate boundaries where magma wells up from below creating new oceanic crust. Ocean trenches form where crustal plates plunge back into the mantle.

When sea floor spreading occurs new crust is added to the ocean floor?

Terms in this set (21) What is the process of sea-floor spreading? In sea-floor spreading the sea floor spreads apart along both sides of a mid-ocean ridge as new crust is added. As a result the ocean floors move like conveyor belts carrying the continents along with them.

Which statement describes one event that happens at deep ocean trenches?

The destruction of crust occurs at deep-sea trenches. Oceanic rocks are pillow-shaped when formed.

What happens if the mid-ocean ridge creates more crust that can be swallowed by deep ocean trenches What do you think is going to happen to the size of the ocean floor?

How are the sizes of Earth’s oceans determined? The sizes of Earth’s oceans are determined by how fast new crust is being created at mid-ocean ridges and how fast old crust is being swallowed up at deep-ocean trenches An ocean surrounded by many trenches may shrink. An ocean with few trenches will probably grow larger.

What type of rock is basalt?

Basalt is a hard black volcanic rock. Basalt is the most common rock type in the Earth’s crust. Depending on how it is erupted basalt can be hard and massive (Figure 1) or crumbly and full of bubbles (Figure 2).

What makes the old oceanic crust denser than the new oceanic crust?

Explanation: At mid-ocean ridges two tectonic plates move apart and molten magma rises to form new oceanic crust. As this crust moves away from the ridge over time it gets older and cooler and its density increases.