Deepest oceanic trenches
| Trench | Ocean | Lowest Point | Maximum Depth |
| Mariana Trench | Pacific Ocean | Challenger Deep | 10,920 m (35,830 ft) |
| Tonga Trench | Pacific Ocean | Horizon Deep | 10,820 m (35,500 ft) |
| Philippine Trench | Pacific Ocean | Emden Deep | 10,540 m (34,580 ft) |
| Kuril–Kamchatka Trench | Pacific Ocean | 10,542 m (34,587 ft) |
What are ocean trenches and how are they formed?
- National Geographic News: Life is Found Thriving at Ocean’s Deepest Point
- AGU Geojourneys blog: Geology Word of the Week: A is for Accretionary Wedge
- NOAA: How Does Pressure Impact Animals in the Ocean?
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.
What is the deepest trench?
A TRENCH that has been a nightmare for motorists travelling on one of the metro’s busiest roads sometimes becomes so deep that one’s ankles will disappear when one steps in it. This is something that Ward 6 Councillor, Gert Engelbrecht, has experienced ...
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) …
Where are ocean trenches located?
Most of them are found in the Pacific Ocean, but some of them are located in and around the Indian Ocean, and margins of the Atlantic Ocean and Mediterranean Sea. The environmental conditions at such a depth as that of ocean trenches is quite adverse. The pressure at the trenches goes as high as 1,000 times the pressure at the surface.
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.
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.
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 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.
Where do ocean 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. Ocean trenches are deep narrow rifts or valleys in the ocean floor.
What are the two types of trenches?
There are two kinds of trenches: those associated with island arcs – formed from two oceanic plates converging. those associated with continents – formed from oceanic plates and continental plates converging. The trenches associated with island arcs are deeper than those associated with continents.
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.
How deep is the Mariana trench?
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 is the crust of the Earth called?
The different parts of the crust are sometimes referred to as oceanic crust and continental crust.
What are the adaptations of the oceanic trenches?
Adaptations Of Organisms In Oceanic Trenches. Amphipods can be found deep in the ocean trenches. Oceanic trenches have no light, and it is utterly dark in these depths. Some animals have responded to the challenge by developing huge eyes to capture the faintest trace of light.
Where are trenches found?
Ocean trenches are found throughout the world’s oceans, but the majority of them occur in the Pacific Ocean. Ocean trenches are found in every ocean basin in the world. Oceanographers have identified forty-six different trenches that form part of the hadal zone in the world.
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 ...
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.
How deep are accretionary trenches?
It is therefore not surprising that the deepest trenches (deeper than 8,000 m (26,000 ft)) are all nonaccretionary. In contrast, all trenches with growing accretionary prisms are shallower than 8,000 m (26,000 ft). A second order control on trench depth is the age of the lithosphere at the time of subduction.
What is the deepest part of the ocean?
The Mariana trench contains the deepest part of the world's oceans, and runs along an oceanic-oceanic convergent boundary. It is the result of the oceanic Pacific plate subducting beneath the oceanic Mariana plate.
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 is the boundary of a plate?
The plate boundary is defined by the trench axis itself. Beneath the inner trench wall, the two plates slide past each other along the subduction decollement, the seafloor intersection of which defines the trench location. The overriding plate typically contains a volcanic arc and forearc region.
How deep is the Puerto Rico trench?
Further north, far from major sediment sources, the Puerto Rico Trench is over 8,600 m (28,200 ft) deep and there is no active accretionary prism.
What are the deep trenches in the ocean called?
Some are so deep that their bottoms are as far away from us as the upper reaches of our atmosphere. These regions are called the deep ocean trenches and if they were on a continent, they'd be deep jagged canyons.
Where do deep ocean trenches meet?
The boundary where they meet is where deep ocean trenches exist. For example, the Mariana Trench, which lies beneath the Pacific Ocean near the Mariana island chain and not far from the coast of Japan, is the product of what's called "subduction.".
Why are deep ocean trenches so inhospitable to humans?
That's because there were no vessels that could explore those regions. Visiting them requires specialized submersible craft. These deep ocean canyons are extremely inhospitable to human life. Although people did send diving bells into the ocean prior to the middle of the last century, none went as deep as a trench. The pressure of the water at those depths would instantly kill a person, so no one dared venture into the deeps of the Mariana Trench until a safe vessel was designed and tested.
Why is the trench called the Ring of Fire?
That action cracked Earth's surface and the resulting fracture zone became the trench. Most of the deepest trenches are found in the Pacific Ocean, which overlies the so-called "Ring of Fire". That region gets the name due to tectonic activity that also spurs the formation of volcanic eruptions deep beneath the water.
Why do trenches have deeper sediments?
Older sections of the sea floor have deeper trenches, which happens because heavier rock tends to sink over time.
What is the Eurasian plate sliding over?
Beneath the trench, the Eurasian plate is sliding over a smaller one called the Philippine Plate, which is sinking into the mantle and melting. That combination of sinking and melting formed the Mariana Trench. A combined image of Earth's plates, the plate boundaries, and ocean bottom mapping (called bathymetry).
What is a tench?
Technically, tenches are long, narrow depressions on the seafloor. The harbor fantastic life forms not seen on the surface, animals and plants that thrive in the extreme conditions of the trenches. It has only been in the past few decades that humans could even consider venturing that deep to explore.
What is the trench between two plates?
A trench forms between the two plates in a subduction zone. Trenches are depression in the ocean floor. They are also the deepest part of the seafloor. Trenches form natural boundaries between two tectonic plates.
What boundary is the trench between two tectonic plates?
Ocean Trenches. Ocean trenches develop in subduction zones at a convergent boundary between two tectonic plates. When a continental plate collides with an oceanic plate the oceanic plate is forced beneath the lighter continental plate.
What is the name of the mountain range that forms on the continental side of a trench?
Volcanic arcs. Volcanic mountain ranges form on the continental side of a trench where a continental and an oceanic plate converge. The mountain range is called a volcanic arc. If two oceanic crusts converge an island arc forms on the overriding plate parallel to the trench. Volcanic arcs and island arcs have volcanic mountains ...
How many trenches are there on Earth?
There are 20 major trenches on Earth and 17 of these trenches can be found around the Pacific Ocean Basin. The Mariana Trench contains the Challenger Deep, which is the deepest known place on our planet.
How many sea mounts are there in the ocean?
Sea mount There are more than 60,000 sea mounts located in the world's oceans. Oceanic Zones Find out about the four major zones where plants and animals live in the ocean. Ocean Facts Discover what causes tsunamis, where ocean trenches are located and how the Mid-Atlantic Ridge was discovered.
Where is the Mid Atlantic Ridge?
Mid Atlantic Ridge The Mid-Atlantic Ridge is a mountain range that runs down the center of the Atlantic Ocean through Iceland. Ocean Trenches Ocean trenches are found all around the Pacific Ring of Fire. Find out how and why they develop. Sea mount There are more than 60,000 sea mounts located in the world's oceans.
How are ocean trenches formed?
Tectonic plates are the cause of the formation of ocean trenches. They are formed mainly by subduction. Sub duction is a geophysical process in which two or more tectonic plates converge on each other. Normally, the oldest and densest tectonic plate is the one that is pushed underneath the lightest plate. This plate movement causes the ocean floor of the outer crust to curve into a slope. Usually this depression that forms is shaped like a V. This is how ocean trenches are formed.
How deep is the ocean trench?
The deepest oceanic trench is the Mariana Trench located near the Marine Islands with a length of more than 2,542 kilometers. The vast majority of these graves are located in the Pacific Ocean specifically in the area called Ring of Fire. In this pit is the Challenger Abyss that has a depth of 10.911 meters at the deepest part. It is considered as the maximum depth that the ocean reaches. It means that if we compare the Mariana Trench with Mount Everest, it is 2.000 meters deep.
Why are ocean trenches important?
Human beings have always declared that ocean trenches are of great importance. The knowledge about its interior is very limited of great depth life. Also to the remote location of its existence. However, scientists know the fundamental role they play in our lives. Much of the physical activities take place in the subduction zones. This can have a devastating effect on coastal communities and the global economy. There is more to see than the earthquakes produced on the sea floor in the subduction zone They were responsible for the tsunami in Japan in 2011.
What happens when a plate is subducted?
When it is on the edge of a dense tectonic plate with another less dense edge, the plate with higher density bends downward. The place where the densest plate that is subducted is what is known as a subduction zone. This process makes things geological and dynamic elements. Many of these ocean trenches are responsible for numerous earthquakes at sea. And it is that in the subduction one plate on the other generates a quite strong friction force. They are usually the epicenter of large earthquakes and some of the deepest earthquakes on record.
How deep is the ocean trench?
This valley is so deep that if you were to place Mount Everest at the bottom of the valley and stand on the summit at 29,029 feet, you would still be approximately 7,000 feet from the top. In order to visit this really deep valley, ...
Where are the most ocean trenches?
Most ocean trenches are in the Pacific. The loss of the earth's crust at ocean trenches is made up for by seafloor spreading elsewhere, which is when tectonic plates are pulling apart. Underwater earthquakes at subduction zones can set off dangerous tsunamis.
What is the term for the area where one plate slides underneath another plate?
Lesson Summary. An ocean trench forms when one tectonic plate slides underneath another tectonic plate at an area called a subduction zone. In subduction, continents can tuck under each other just like one piece of paper can tuck under another. A tectonic plate is a large portion of the earth's crust.
Which plate is the deepest in the ocean?
The heavier oceanic plate slips underneath the continental plate, bending and melting as it goes, and setting off earthquakes and forming chains of volcanoes. Ocean trenches are the deepest parts of the ocean, with the Mariana Trench near Guam having the deepest spot on Earth, the Challenger Deep. The deepest point of the Challenger Deep is 36,070 ...
Which plate is heavier, continental or oceanic?
The heavier tectonic plate always tucks under the lighter tectonic plate, and in terms of plate weights, the continental plates are lighter than oceanic plates. Often when you see an arc of volcanic islands, like the Aleutian Islands, they are there because a subduction zone is near.
How hot is the water at the bottom of a trench?
The bottom of the trench can have 1,000 times the pressure you would feel at sea level, not to mention there are underwater vents at subduction zones that spew out gases (like liquid sulfur and carbon dioxide) that can reach temperatures of 217°. And despite those hot gas temperatures, elsewhere the water is near-freezing.
How wide is the Mariana trench?
It averages only 43 miles wide. The Mariana Trench is the biggie, but there are others. Along the West coast of South America there is the Peru-Chile trench, and even in the Atlantic, which doesn't have as many trenches, there is the Puerto Rico Trench, which is an impressive 28,232 feet deep and 175 miles long.
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.