This is a list of submarine topographical features, oceanic

landform A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, ...

s and

topographic Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary scie ...

elements.

Abyssal plain

abyssal plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface ...

is an underwater

plain In geography, a plain is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and as plateaus or uplands ...

on the deep

ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

, usually found at depths between and . Lying generally between the foot of a

continental rise The continental rise is a low-relief zone of accumulated sediments that lies between the continental slope and the abyssal plain. It is a major part of the continental margin, covering around 10% of the ocean floor. Formation This geologic str ...

and a

mid-ocean ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a div ...

, abyssal plains are among the flattest, smoothest and least explored regions on Earth. Abyssal plains are key geologic elements of

oceanic basin In hydrology, an oceanic basin (or ocean basin) is anywhere on Earth that is covered by seawater. Geologically, ocean basins are large  geologic basins that are below sea level. Most commonly the ocean is divided into basins fol ...

s (the other elements being an elevated mid-ocean ridge and flanking abyssal hills). In addition to these elements, ''active'' oceanic basins (those that are associated with a moving

plate tectonic Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

boundary) also typically include an

oceanic trench Oceanic trenches are prominent long, narrow topographic depressions of the ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about of oceanic tren ...

and a

subduction zone Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

. Abyssal plains cover more than 33% of the ocean floor (about 23% of Earth's surface), but they are poorly preserved in the sedimentary record because they tend to be consumed by the subduction process. The abyssal plain is formed when the lower

oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic ...

is melted and forced upwards by the

asthenosphere The asthenosphere () is the mechanically weak and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between ~ below the surface, and extends as deep as . However, the lower boundary of the asthenosphere is ...

layer of the upper mantle. As this

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

ic material reaches the surface at mid-ocean ridges, it forms new oceanic crust. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand ...

s, mainly

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay pa ...

and

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel ...

. Much of this sediment is deposited from

turbidity current A turbidity current is most typically an underwater current of usually rapidly moving, sediment-laden water moving down a slope; although current research (2018) indicates that water-saturated sediment may be the primary actor in the process. T ...

s that have been channeled from the

continental margin A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

s along

submarine canyon A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to 5 km, from c ...

s down into deeper water. The remainder of the sediment is composed chiefly of

pelagic sediments Pelagic sediment or pelagite is a fine-grained sediment that accumulates as the result of the settling of particles to the floor of the open ocean, far from land. These particles consist primarily of either the microscopic, calcareous or siliceo ...

. Use of a continuously recording

fathometer Echo sounding or depth sounding is the use of sonar for ranging, normally to determine the depth of water (bathymetry). It involves transmitting acoustic waves into water and recording the time interval between emission and return of a pulse; ...

enabled Tolstoy & Ewing in the summer of 1947 to identify and describe the first abyssal plain. This plain, located to the south of

Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

, is now known as the

Sohm Abyssal Plain The Sohm Abyssal Plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of ...

. Following this discovery many other examples were found in all the oceans.

List of abyssal plains and oceanic basins

Following is a list of named

abyssal plains An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface ...

and

Oceanic trenches

Oceanic trench Oceanic trenches are prominent long, narrow topographic depressions of the ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about of oceanic tren ...

es are long, narrow

depressions of the

seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most o ...

. They are the deepest parts of the ocean floor, and they define one of the most important natural boundaries on the Earth's solid surface: the one between two

lithospheric A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years or ...

plates. Trenches are a distinctive morphological feature of

plate boundaries Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

. Trenches are found in all oceans with the exception of the Arctic Ocean and they are most common in the North and South Pacific Oceans. There are three types of lithospheric plate boundaries: 1.) divergent (where lithosphere and oceanic crust is created at mid-ocean ridges), 2.) convergent (where one lithospheric plate sinks beneath another and returns to the mantle), and 3.) transform (where two lithospheric plates slide past each other). An oceanic trench is a type of convergent boundary at which two oceanic lithospheric slabs meet; the older (and therefore denser) of these slabs flexes and subducts beneath the other slab. Oceanic lithosphere moves into trenches at a global rate of about a tenth of a square meter per second. Trenches are generally parallel to a

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plat ...

island arc Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...

, and about 200 km from a volcanic arc. Oceanic trenches typically extend 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor. The greatest ocean depth to be sounded is in the

Challenger Deep The Challenger Deep is the deepest-known point of the seabed of Earth, with a depth of by direct measurement from deep-diving submersibles, remotely operated underwater vehicles and benthic landers, and (sometimes) slightly more by sonar bathym ...

of the

Mariana Trench The Mariana Trench is an oceanic trench located in the western Pacific Ocean, about east of the Mariana Islands; it is the deepest oceanic trench on Earth. It is crescent-shaped and measures about in length and in width. The maximum known ...

, at a depth of 10,911 m (35,798 ft) below sea level.

List of oceanic trenches

The following is a list of the deepest parts of the Earth's oceans and seas (all depths are measured from

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardis ...

): *''Entries marked with * are the deepest parts of their respective water bodies, but are not

es.''

Oceanic plateau

oceanic plateau An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides. There are 184 oceanic plateaus in the world, covering an area of or about 5.11% of the ...

is a large, relatively flat submarine region that rises well above the level of the ambient seabed. While many oceanic plateaus are composed of

continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called '' sial'' be ...

, and often form a step interrupting the

continental slope A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

, some plateaus are undersea remnants of

large igneous province A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive (sills, dikes) and extrusive (lava flows, tephra deposits), arising when magma travels through the crust towards the surface. The formation ...

s. Continental crust has the highest amount of

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ...

(such rock is called

felsic In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted with mafic rocks, wh ...

). Oceanic crust has a smaller amount of silicon (

mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks in ...

rock). The anomalous

volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a ...

associated with the formation of oceanic plateaux at the time of the

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in ...

–

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...

boundary (90.4

million years The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago) ...

) ago may have been responsible for the environmental disturbances that occurred at that time. The physical manifestations of this were elevated atmospheric and oceanic temperatures, a significant sea-level transgression, and a period of widespread anoxia, leading to the extinction of 26% of all

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

. These eruptions would also have resulted in the emission of large quantities of

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...

into the atmosphere, leading to

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

. Additionally, the emission of

sulfur monoxide Sulfur monoxide is an inorganic compound with formula . It is only found as a dilute gas phase. When concentrated or condensed, it converts to S2O2 ( disulfur dioxide). It has been detected in space but is rarely encountered intact otherwise. St ...

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The under ...

carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simpl ...

, and

halogen The halogens () are a group in the periodic table consisting of five or six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In the modern IUPAC nomenclature, this grou ...

s into the oceans would have made seawater more

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a se ...

ic resulting in the dissolution of

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...

, and further release of . This runaway greenhouse effect was probably put into reverse by the decline of the anomalous volcanic activity and by increased -driven productivity in oceanic surface waters, leading to increased organic carbon burial, black

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

deposition, anoxia and

mass extinction An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...

in the ocean basins. Zealandia-Continent map en

List of oceanic plateaus

* Campbell Plateau (South Pacific) * Challenger Plateau (South Pacific) * Agulhas PlateauUenzelmann-Neben, G., K. Gohl, A. Ehrhardt, and M. Seargent (1999)
Agulhas Plateau, SW Indian Ocean: New Evidence for Excessive Volcanism
Geophysical Research Letters, 26(13), 1941–1944. (Southwest Indian) * Caribbean–Colombian Plateau (Caribbean) * Exmouth Plateau (Indian) * Hikurangi Plateau (Southwest Pacific) *

Kerguelen Plateau The Kerguelen Plateau (, ), also known as the Kerguelen–Heard Plateau, is an oceanic plateau and a large igneous province (LIP) located on the Antarctic Plate, in the southern Indian Ocean. It is about to the southwest of Australia and is ...

(Indian) * Manihiki Plateau (Southwest Pacific) * Marquesas Plateau (Southwest Pacific) *

Mascarene Plateau The Mascarene Plateau is a submarine plateau in the Indian Ocean, north and east of Madagascar. The plateau extends approximately , from Seychelles in the north to Réunion in the south. The plateau covers an area of over of shallow water, wi ...

(Indian) * Naturaliste Plateau (Indian) *

Ontong Java Plateau The Ontong Java Plateau (OJP) is a massive oceanic plateau located in the southwestern Pacific Ocean, north of the Solomon Islands. The OJP was formed around (Ma) with a much smaller volcanic event around 90 Ma. Two other southwestern Pacifi ...

(Southwest Pacific) * Shatsky Rise (North Pacific) * Vøring Plateau (North Atlantic) *

Wrangellia Terrane The Wrangellia Terrane (named for the Wrangell Mountains, Alaska) is a crustal fragment (terrane) extending from the south-central part of Alaska and along the Coast of British Columbia in Canada. Some geologists contend that Wrangellia extends ...

(Northeast Pacific) * Yermak Plateau (Arctic)

Mid-ocean ridges

is a general term for an underwater

mountain system A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have arise ...

that consists of various mountain ranges (chains), typically having a valley known as a

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...

running along its spine, formed by

plate tectonics Plate tectonics (from the la, label= Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of larg ...

. This type of oceanic ridge is characteristic of what is known as an oceanic spreading center, which is responsible for

seafloor spreading Seafloor spreading or Seafloor spread is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener a ...

List of mid-ocean ridges

Aden Ridge The Aden Ridge is a part of an active oblique rift system located in the Gulf of Aden, between Somalia and the Arabian Peninsula to the north. The rift system marks the divergent boundary between the Somali and Arabian tectonic plates, extending ...

* American–Antarctic Ridge *

Carlsberg Ridge The Carlsberg Ridge is the northern section of the Central Indian Ridge, a divergent tectonic plate boundary between the African Plate and the Indo-Australian Plate, traversing the western regions of the Indian Ocean. The ridge of which the Carl ...

Central Indian Ridge The Central Indian Ridge (CIR) is a north–south-trending mid-ocean ridge in the western Indian Ocean. Geological setting The morphology of the CIR is characteristic of slow to intermediate ridges. The axial valley is 500–1000 m deep; ...

Chile Rise The Chile Ridge, also known as the Chile Rise, is a submarine oceanic ridge formed by the divergent plate boundary between the Nazca Plate and the Antarctic Plate. It extends from the triple junction of the Nazca, Pacific, and Antarctic plates ...

Cocos Ridge Cocos may refer to: Geography * Cocos, Bahia, Brazil * Cocos, Quebradillas, Puerto Rico, a barrio * Cocos Island (disambiguation) ** Cocos (Keeling) Islands, a territory of Australia in the Indian Ocean *** Shire of Cocos, a local government a ...

East Pacific Rise The East Pacific Rise is a mid-ocean rise (termed an oceanic rise and not a mid-ocean ridge due to its higher rate of spreading that results in less elevation increase and more regular terrain), a divergent tectonic plate boundary located alon ...

East Scotia Ridge The Scotia Plate () is a tectonic plate on the edge of the South Atlantic and Southern oceans. Thought to have formed during the early Eocene with the opening of the Drake Passage that separates South America from Antarctica, it is a minor plat ...

* Explorer Ridge *

Gakkel Ridge The Gakkel Ridge (formerly known as the Nansen Cordillera and Arctic Mid-Ocean Ridge) is a mid-oceanic ridge, a divergent tectonic plate boundary between the North American Plate and the Eurasian Plate. It is located in the Eurasian Basin of the ...

(Mid-Arctic Ridge) * Gorda Ridge * Juan de Fuca Ridge * Knipovich Ridge (between Greenland and Spitsbergen) *

Kolbeinsey Ridge The Kolbeinsey Ridge is a segment of the Mid-Atlantic Ridge located to the north of Iceland in the Arctic Ocean. It is bounded to the south by the Tjörnes Fracture Zone, which connects the submarine ridge to the on-shore Northern Volcanic Zone ri ...

(North of Iceland) *

Mid-Atlantic Ridge The Mid-Atlantic Ridge is a mid-ocean ridge (a divergent or constructive plate boundary) located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. In the North Atlantic, the ridge separates the North A ...

Mohns Ridge Mohns is the surname of: * Arthur Mohns (1896-?), German footballer *Doug Mohns Douglas Allen "Diesel" Mohns (December 13, 1933 – February 7, 2014) was a professional ice hockey player who played 22 seasons in the National Hockey League from 1 ...

Norfolk Ridge The Norfolk Ridge is a long submarine ridge running between New Caledonia and New Zealand, about 1300 km off the east-coast of Australia. It is part of a complex region of ridges between the crust of the Pacific Basin and the continental c ...

* Pacific–Antarctic Ridge * Palau–Kyushu Ridge * Reykjanes Ridge (south of Iceland) *

Southeast Indian Ridge The Southeast Indian Ridge (SEIR) is a mid-ocean ridge in the southern Indian Ocean. A divergent tectonic plate boundary stretching almost between the Rodrigues Triple Junction () in the Indian Ocean and the Macquarie Triple Junction () in t ...

* Southwest Indian Ridge * West Mariana Ridge

References

External links

* {{DEFAULTSORT:Submarine Topographical Features * * Lists of landforms Marine geology Abyssal plains Oceanic plateaus Oceanic ridges Oceanic trenches Plate tectonics