Deepest oceanic trenches
| Trench | Ocean | Lowest Point | Maximum Depth | Source |
| Mariana Trench | Pacific Ocean | Challenger Deep | 10,920 m (35,830 ft) | [43] |
| Tonga Trench | Pacific Ocean | Horizon Deep | 10,820 m (35,500 ft) | [43] |
| Philippine Trench | Pacific Ocean | Emden Deep | 10,540 m (34,580 ft) | [44] |
| Kuril–Kamchatka Trench | Pacific Ocean | 10,542 m (34,587 ft) | [44] |
How deep ocean trenches are formed?
How are deep ocean trenches formed? 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.
How are deep sea trenches formed?
Trenches are formed through subduction, which occurs when tectonic plates collide and push one plate beneath the other. Trenches can be found all over the surface floor of the ocean at subduction zones. The Mariana trench is the deepest known point in the ocean at over 35,000 feet deep.
What is the deepest trench?
What are the deepest trenches in the world?
- Mariana Trench. Located in the western Pacific Ocean, the Marina Trench is considered to be the deepest part of the Earth’s surface. …
- Tonga Trench. …
- Philippine Trench. …
- Kuril- Kamchatka Trench. …
- Kermadec Trench. …
- Izu-Ogasawara Trench. …
- Japan Trench. …
- Puerto Rico Trench.
What are the names of the oceanic trenches?
the deepest point in each of the earth's oceans are as follows; the arctic ocean's eurasian basin at 5,450 meters (17,881 feet) deep, the indian ocean's java trench at 7,725 meters (25,344 feet) deep, the atlantic ocean's puerto rico trench at 8,648 meters (28,374 feet) deep and the pacific ocean's mariana trench at 11,033 meters (36,201 feet) …
What causes trenches in the ocean?
The subduction zones and the activities resulting from it are the cause of formation of oceanic trenches. The movement of the Earth’s crust at the convergent boundaries of tectonic plates, be it oceanic crust and continental crust or two oceanic crusts, result in a steep deep valley with the two crusts acting as its walls. Oceanic crust is always heavier than the continental crust. The heavier crust has a moderate slope, whereas the lighter crust forms the inner wall, and it has a steep slope. The rate of disappearance of the oceanic crust into the trenches is estimated to be about the tenth part of a square meter per second every year.
Where is the deepest trench in the ocean?
Mariana Trench is famed as the deepest trench in the entire stretch of oceanic crust on the Earth and is located in the east of Mariana islands near Guam. It is estimated to be 36,037 feet (10,984 m) below the ocean’s surface.
What happens when the oceanic crust converges with the continental crust?
When this crust converges with another oceanic or continental crust, the heavier crust melts and slides (subducts) under the lighter crust due to gravitational action. The heavier plate sinks into or converges into the mantle.
How does subduction occur?
A subduction zone and its occurrence can be traced from the formation of mid-ocean ridges . These mid-ocean ridges are a range of volcanic hills found underwater. The flowing mantle material out of these mid-ocean ridges forms the new oceanic crust. As these newly formed crusts move away from the ridges, they start spreading over the ocean bed and cool down. The cooled oceanic crust gets denser and heavier as it starts contracting. When this crust converges with another oceanic or continental crust, the heavier crust melts and slides (subducts) under the lighter crust due to gravitational action. The heavier plate sinks into or converges into the mantle. A depression is formed along the converging ridge of the plates. These depressions are called oceanic trenches.
Why do trenches occur?
The reason behind these subsequent occurrences is increase in the mantle material due to the melting of ocean floor subduction. The molten material then rises above the crust through volcanic chains parallel to the trench and around it. Continental shelves or volcanic belts are found within 200 km from an oceanic trench and are considered to be the landmark for locating it. The Aleutian Arc has been formed as the Pacific Plate subducts beneath the North American Plate.
How deep is the Puerto Rico trench?
Let's Work Together! The deepest trench in the crust of Atlantic Ocean is the Puerto Rico Trench, which is 8,600 meters (28,232 feet) deep, and its length is around 280 kilometers (175 miles).
Why does mantle material rise above the crust?
The reason behind these subsequent occurrences is increase in the mantle material due to the melting of ocean floor subduction. The molten material then rises above the crust through volcanic chains parallel to the trench and around it.
Where do trenches form?
Ocean trenches form on tectonic plate boundaries where the dense plate subducts below the less dense plate due to plate movement. These destructive plate boundaries result in a steep V-shaped valley or trench on the ocean floor. Ocean trenches occur in all the world’s ocean basins.
What Is The Deepest Ocean Trench?
The deepest oceanic trench is the Mariana Trench at 36 201 feet. The trench is 1585 miles long and 42.8 miles wide and is formed when the Pacific Plate subducted beneath the Philippine Sea Plate. The reason that the Mariana Trench is so deep is that the crust at the edge of the Pacific plate is one of the oldest portions of oceanic crust in the world. This makes it very dense.
What Kind Of Animals Live At The Bottom Of Ocean Trenches?
Fish seem to live at a maximum-depths of 26 000 to 27 000 feet. Beyond that, there are other life forms, such as crustaceans known as amphipods. The amphipods grow to giant sizes in the deep cold water. Most normal amphipods are approximately an inch to two inches long, but they grow to more than a foot long in the trenches. As they look like giant shrimp, it gives an impression of an alien world down in the depths.
What is the deepest part of the ocean?
Ocean trenches are deep V-shaped trenches in the hadal zone of the earth. (The hadal zone is named after Hades and is the deepest part of the ocean). The landward side is steeper than the seaward side. There are two kinds of trenches: those associated with island arcs – formed from two oceanic plates converging.
What is the crust of the Earth called?
The different parts of the crust are sometimes referred to as oceanic crust and continental crust.
What is the difference between continental and oceanic plates?
Oceanic plates consist of denser rocks than continental plates. When an oceanic plate and a continental plate converge, the dense oceanic plate slides under the continental plate – the oceanic plate is said to subduct beneath the continental plate. The result is a very deep trench that runs along the subduction zone and is known as an oceanic trench .
How is magma forced up?
The magma that is forced upwards forms mountain ridges or volcanic islands that run parallel to the ocean trench. The continental plate is thrust upwards by the oceanic plate.
What are ocean trenches?
Oceanic trenches are topographic depressions of the seafloor, relatively narrow in width, but very long. These oceanographic features are the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates ...
How long are oceanic trenches?
An individual trench can be thousands of kilometers long. Most trenches are convex towards the subducting slab, which is attributed to the spherical geometry of the Earth.
What is the name of the feature of the Earth's distinctive plate tectonics?
Oceanic trenches are a feature of the Earth's distinctive plate tectonics. They mark the locations of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few millimeters to over ten centimeters per year. Oceanic lithosphere moves into trenches at a global rate of about 3 km 2 /yr. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to and about 200 km (120 mi) from a volcanic arc .
How is the outer slope angle of a trench determined?
The outer slope angle of the trench is determined by the bending radius of the subducting slab, as determined by its elastic thickness. Since oceanic lithosphere thickens with age, the outer slope angle is ultimately determined by the age of the subducting slab. The inner slope angle is determined by the angle of repose of the overriding plate edge. This reflects frequent earthquakes along the trench that prevent oversteepening of the inner slope.
What is trench in science?
Trenches are related to but distinguished from continental collision zones (such as that between India and Asia forming the Himalaya ), where continental crust enters a subduction zone. When buoyant continental crust enters a trench, subduction eventually stops and the area becomes a zone of continental collision.
Why is the Hellenic trench unusual?
The Hellenic Trench of the Hellenic arc system is unusual because this convergent margin subducts evaporites. The slope of the surface of the southern flank of the Mediterranean Ridge (its accretionary prism) is low, about 1°, indicating very low shear stress on the decollement at the base of the wedge.
What are trenches and troughs?
Trenches are geomorphologically distinct from troughs. Troughs are elongated depressions of the sea floor with steep sides and flat bottoms, while trenches are characterized by a V-shaped profile. Trenches that are partially infilled are sometimes described as troughs (such as the Makran Trough) and sometimes trenches are completely buried and lack bathymetric expression (such as the Cascadia subduction zone, which is completely filled with sediments) but the fundamental plate tectonics structures that these represent are those of oceanic trenches. However, many troughs represent different kinds of tectonic structures, such as the Lesser Antilles Trough, which is the forearc basin of the Lesser Antilles subduction zone; the New Caledonia trough, which is an extensional sedimentary basin related to the Tonga-Kermadec subduction zone; and the Cayman Trough, which is a pull-apart basin within a transform fault zone.
Where are oceanic trenches formed?
In geology and oceanography, it is known as oceanic trench or marine trench to the long and narrow depressions of the seafloor, in the form of a trench, that are commonly formed in the adjacencies of the continental shelves or of the coasts of the volcanic islands, that is to say, in the regions in which one tectonic plate subducts under another.
When does a trench form?
A trench forms when one tectonic plate dives under another.
What is the deepest area in the Atlantic Ocean?
Puerto Rico Trench. As its name suggests, it is located in the Atlantic Ocean, serving as the border with the Caribbean Sea. It extends for 1,500 km throughout the Lesser Antilles, and is the deepest area in the Atlantic, registering 9,200 meters below sea level.
How deep is the South Sandwich trench?
It is 965 kilometers long and has a maximum recorded depth of 8,428 meters below the surface.
How deep is the Tonga trench?
Tonga Trench. Located northwest of New Zealand, in the South Pacific Ocean, it has a maximum depth of around 10,822 meters below the sea surface and is right next to the Kermadec Trench.
How hot is the ocean trench?
In addition, the pressures in the ocean trenches are immense, given the mass of water above, and the temperatures remain around 4 ° C, so they are not the most welcoming places on the planet.
Where is Bougainville Trench?
Bougainville Trench or from New Britain. Located east of the island of New Guinea and the Solomon Islands, in the Pacific Ocean, about 1500 km from Australia, its name pays tribute to the French sailor Louis Antoine de Bougainville (1729-1811). It reaches depths of 9140 meters below the sea surface.
Where are ocean trenches located?
Trenches are located in subduction zones at or near a convergent boundary, continental crust, and/ or volcanic islands. The Mariana Trench is the deepest known trench globally, located more than 35,000 feet below sea level. The hadal zone is the zone associated with the area at the bottom of the ocean where trenches are found.
How are trenches formed?
An ocean trench is an indentation in the ocean floor and is the deepest area of the ocean. Trenches are formed through subduction, which occurs when tectonic plates collide and push one plate beneath the other. Trenches can be found all over the surface floor of the ocean at subduction zones. The Mariana trench is the deepest known point in the ocean at over 35,000 feet deep. Life in these deep areas has evolved to survive in high-pressure, low-oxygen environments. We are still learning so much about trenches and the organisms that live there; however, recent studies suggest these organisms can help us better understand the evolution of life on earth.
What is the deepest trench in the ocean?
The Mariana Trench is the deepest known area in the ocean.
How does subduction cause earthquakes?
The push of volcanic material results in the formation of islands and causes large earthquakes. Earthquakes caused by subduction are some of the largest in the world, even when compared to terrestrial earthquakes, and can happen anywhere a subduction zone is present. These large earthquakes can sometimes even ripple out and be the cause of major tsunamis. The volcanic material in lower levels of the trenches can feed certain organisms as well. While crust is being pulled down below the trenches, it causes a deeper hole to form on the outer surface, causing the trenches to be bottomless. We can measure the depth of the ocean using a process called bathymetry. There are two main layers of the mantle involved in the process of subduction, which is the lithosphere and asthenosphere. The lithosphere is the upper layer of the mantel and consists of the tectonic plates. In contrast, the asthenosphere is the lower layer of the mantel and consists of lava and rock at very high temperatures from the earth's core.
What is the process of a plate boundary?
The heavy plates are pushed below the new and light plates, and this push causes the indent to occur, a process called subduction and can create a subduction zone. This is a type of convergent plate boundary meaning where plates converge, which is one of three processes when plates come together.
How deep is the Mariana trench?
The Mariana trench located off the coast of Aisa is the deepest trench in the world; it is recorded as being over 35,000 feet deep.
How do organisms adapt to the ocean?
However, even with these fundamental requirements for life being scarce, organisms have been able to adapt. Many deep-sea organisms have evolved to live in areas where other organisms cannot. They can do this by using tools such as bioluminescence, feeding on carbon instead of oxygen, and dwelling near hot vents that release nutrients into the water column.
Overview
Oceanic trenches are prominent long, narrow topographic depressions of the ocean floor. They are typically 50 to 100 kilometers (30 to 60 mi) wide and 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about 50,000 kilometers (31,000 mi) of oceanic trenches worldwide, mostly around the Pacific Ocean, but also i…
Geographic distribution
There are approximately 50,000 km (31,000 mi) of convergent plate margins worldwide. These are mostly located around the Pacific Ocean, but are also found in the eastern Indian Ocean, with a few shorter convergent margin segments in other parts of the Indian Ocean, in the Atlantic Ocean, and in the Mediterranean. They are found on the oceanward side of island arcs and Andea…
History of the term "trench"
Trenches were not clearly defined until the late 1940s and 1950s. The bathymetry of the ocean was poorly known prior to the Challenger expedition of 1872–1876, which took 492 soundings of the deep ocean. At station #225, the expedition discovered Challenger Deep, now known to be the southern end of the Mariana Trench. The laying of transatlantic telegraph cables on the seafloor between the continents during the late 19th and early 20th centuries provided further motivatio…
Morphology
Oceanic trenches are 50 to 100 kilometers (30 to 60 mi) wide and have an asymmetric V-shape, with the steeper slope (8 to 20 degrees) on the inner (overriding) side of the trench and the gentler slope (around 5 degrees) on the outer (subducting) side of the trench. The bottom of the trench marks the boundary between the subducting and overriding plates, known as the basal pl…
Trench rollback
Trenches seem positionally stable over time, but scientists believe that some trenches—particularly those associated with subduction zones where two oceanic plates converge—move backward into the subducting plate. This is called trench rollback or hinge retreat (also hinge rollback) and is one explanation for the existence of back-arc basins.
Hydrothermal activity and associated biomes
As sediments are subducted at the bottom of trenches, much of their fluid content is expelled and moves back along the subduction décollement to emerge on the inner slope as mud volcanoes and cold seeps. Methane clathrates and gas hydrates also accumulate in the inner slope, and there is concern that their breakdown could contribute to global warming.
The fluids released at mud volcanoes and cold seeps are rich in methane and hydrogen sulfide, pr…
See also
• List of landforms
• List of submarine topographical features
• Mid-ocean ridge
• Physical oceanography
Bibliography
• Allwrardt, Allan O. (1993). "Evolution of the tectogene concept, 1930-1965" (PDF). Proceedings of the Fifth International Congress on the History of Oceanography. Retrieved 29 September 2021.
• Amos, Jonathan (11 May 2021). "Oceans' extreme depths measured in precise detail". News. BBC. Retrieved 2 October 2021.