geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

, a depression is a landform sunken or depressed below the surrounding area. Depressions form by various mechanisms.

Types

Erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

-related: * Blowout: a depression created by

wind erosion Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials ...

typically in either a partially vegetated sand dune ecosystem or dry soils (such as a post-glacial loess environment). *

Glacial valley U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight s ...

: a depression carved by

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

by a

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

. *

River valley A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams ...

: a depression carved by fluvial erosion by a river. * Area of subsidence caused by the collapse of an underlying structure, such as

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

s in karst terrain. *

Sink A sink is a bowl-shaped plumbing fixture for washing hands, dishwashing, and other purposes. Sinks have a tap (faucet) that supply hot and cold water and may include a spray feature to be used for faster rinsing. They also include a drain t ...

: an endorheic depression generally containing a persistent or intermittent (seasonal)

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

, a salt flat (playa) or dry lake, or an

ephemeral lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

. * Panhole: a shallow depression or basin eroded into flat or gently sloping, cohesive rock.Twidale, C.R., and Bourne, J.A., 2018
Rock basins (gnammas) revisited.
''Géomorphologie: Relief, Processus, Environnement,'' Vol. 24, No. 2. January 2018. Retrieved 9 June 2020. Collapse-related: *

Sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

: a depression formed as a result of the collapse of rocks lying above a hollow. This is common in karst regions. *

Kettle A kettle, sometimes called a tea kettle or teakettle, is a type of pot specialized for boiling water, commonly with a ''lid'', ''spout'', and ''handle'', or a small electric kitchen appliance of similar shape that functions in a self-contained ...

: a shallow, sediment-filled body of water formed by melting glacial remnants in

terminal moraine A terminal moraine, also called end moraine, is a type of moraine that forms at the terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge ...

s. * Thermokarst hollow: caused by volume loss of the ground as the result of permafrost thawing. Impact-related: *

Impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...

: a depression created by an impact, such as a meteorite crater. Sedimentary-related: *

Sedimentary basin Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subside ...

: in sedimentology, an area thickly filled with

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, sa ...

in which the weight of the sediment further depresses the floor of the basin. Structural or tectonic-related: * Structural basin: a syncline-like depression; a region of tectonic downwarping as a result of

isostasy Isostasy (Greek ''ísos'' "equal", ''stásis'' "standstill") or isostatic equilibrium is the state of gravitational equilibrium between Earth's crust (or lithosphere) and mantle such that the crust "floats" at an elevation that depends on its ...

(the

Hawaiian Trough The Hawaiian Trough, otherwise known as the Hawaiian Deep, is a moat-like depression of the seafloor surrounding the Hawaiian Islands. The weight from the volcanic island chain depresses the plastic lithosphere that is already weakened by the u ...

is an example) or subduction (such as the

Chilean Central Valley The Central Valley ( es, Valle Central), Intermediate Depression, or Longitudinal Valley is the depression between the Chilean Coastal Range and the Andes Mountains. The Chilean Central Valley extends from the border with Peru to Puerto Montt in ...

). * Graben or

rift valley A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear d ...

: fallen and typically linear depressions or basins created by

rifting 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-graben wi ...

in a region under tensional

tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...

forces. * Pull-apart basin caused by offset in a strike-slip or

transform fault A transform fault or transform boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subduct ...

(example: the Dead Sea area). *

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 ...

: a deep linear depression on the ocean floor. Oceanic trenches are caused by subduction (when one tectonic plate is pushed underneath another) of

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 ...

beneath either oceanic crust or

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 ...

. * A basin formed by an

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at La ...

: an area depressed by the weight of the ice sheet resulting in

post-glacial rebound Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound ...

after the ice melts (the area adjacent to the ice sheet may be pulled down to create a peripheral depression.) Cites American Geological Institute's Glossary of Geology (3rd edition, revised in 1987). Volcanism-related: *

Caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

: 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 plates a ...

depression resulting from collapse following a

volcanic eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are oft ...

. *

Pit crater A pit crater (also called a subsidence crater or collapse crater) is a depression formed by a sinking or collapse of the surface lying above a void or empty chamber, rather than by the eruption of a volcano or lava vent. Pit craters are found ...

: a volcanic depression smaller than a caldera formed by a sinking, or caving in, of the ground surface lying over a void. * Maar: a depression resulting from

phreatomagmatic eruption Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions cont ...

diatreme A diatreme, sometimes known as a maar-diatreme volcano, is a volcanic pipe formed by a gaseous explosion. When magma rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater, rapid expansion of heated wate ...

explosion.

List of depressions

Aral–Caspian Depression The Aral–Caspian Depression is a lowland depression straddling Europe and Asia around the Aral Sea and Northern Caspian Sea. The most northern part is called the Caspian Depression. The desert part to the east of the Caspian Depression and C ...

Baetic Depression The Baetic Depression ( es, Depresión Bética or ''Depresión del Guadalquivir'') is an alluvial plain in the lower valley of the Guadalquivir in Andalusia, Spain. It is a large triangular-shaped area in the Guadalquivir basin oriented roughly ...

Bodélé Depression The Bodélé Depression (), located at the southern edge of the Sahara Desert in north central Africa, is the lowest point in Chad. It is 500 km long, 150 km wide and around 160 m deep. Its bottom lies about 155 meters above sea leve ...

Caspian Depression The Caspian Depression ( kk, Каспий маңы ойпаты, ''Kaspıı mańy oıpaty''; rus, Прикаспи́йская ни́зменность, p=prʲɪkɐˈspʲijskəjə ˈnʲizmʲɪnnəsʲtʲ, Caspian Lowland) or Pricaspian/Peri-Casp ...

Danakil Depression The Danakil Depression is the northern part of the Afar Triangle or Afar Depression in Ethiopia, a geological depression that has resulted from the divergence of three tectonic plates in the Horn of Africa. Geology The Danakil Depression lie ...

* Eider-Treene Depression * Georgia Depression * Giurgeu-Brașov Depression * Godzareh Depression *

Huancabamba Depression The Huancabamba Depression is an east–west depression through the Andes Mountains of northern Peru. The Huancabamba Depression interrupts the Central and Eastern Cordilleras of the Andes, and the Marañón River and its tributaries drain eastwar ...

Kara Depression The Kara Depression is a depression in the Extreme North of European Russia, by the mouth of Kara River, north-east of the Pay-Khoy Ridge (a continuation of the northern Ural Mountains). It is of diameter 50–60 km and filled with Quate ...

* Karashor Depression *

Kuma–Manych Depression The Kuma–Manych depression ( rus, Кумо–Манычская впадина, Kumo–Manychskaya vpadina), is a geological depression in southwestern Russia that separates the Russian Plain to the north from Ciscaucasia to the south. It is ...

Kuznetsk Depression Kuznetsk Depression (russian: Кузнецкая котловина, ''Kuznetskaya kotlovina'') is located among mountains of South-Central Siberia, including: Kuznetsk Alatau to the Northeast, Salair Ridge to the Southwest, and Mountainous Shor ...

Mari Depression The Mari Depression (russian: Марийская низменность) is a depression in Gornomariysky District, Mari El, Russian Federation. Geography The depression is located on the left side of the Volga, from the western borders of the Ma ...

* Mourdi Depression *

Qattara Depression The Qattara Depression ( ar, منخفض القطارة, Munḫafaḍ al-Qaṭṭārah) is a depression in northwestern Egypt, specifically in the Matruh Governorate. The depression is part of the Western Desert of Egypt. The Qattara Depressi ...

* Regen Depression * Ronda Depression *

Táchira Depression The Táchira Depression ( es, Depresión de Táchira) is a saddle of land connecting the Lake Maracaibo basin to the Orinoco basin in the state of Táchira, Venezuela. It forms a break in the eastern Andes, separating the Tamá Massif to the wes ...

Tunkin Depression Tunkin Depression is a volcanic field in Russia. The Tunkin Depression itself is a tectonic depression, part of the Baikal Rift Zone, between Lake Baikal and Khövsgöl Nuur. The depression consists of a number of basins and is covered by alluvi ...

Turan Depression The Turan Depression, Turan Lowland or Turanian Basin is a low-lying desert basin region stretching from southern Turkmenistan through Uzbekistan to Kazakhstan. Geography The lowland region lies to the east of the Caspian Sea and southeast ...

Turpan Depression The Turpan Depression or Turfan Depression, is a fault-bounded trough located around and south of the city-oasis of Turpan, in the Xinjiang Autonomous Region in far Western China, about southeast of the regional capital Ürümqi. It includes L ...

Tuva Depression Tuva Depression ( rus, Тувинская котловина, r=Tuvinskaya kotlovina) is located among mountains of South Central Siberia — the Tannu-Ola Mountains, Eastern Sayans and Western Sayans, and the Altay Mountains region. It is par ...

Upemba Depression The Upemba Depression (or Kamalondo Depression) is a large marshy bowl area ( depression) in the Democratic Republic of the Congo comprising some fifty lakes, including 22 of relatively large size including Lake Upemba (530 km) and Lake Kisale ...

Weser Depression The Weser Depression (german: Weserniederung) or Weser Lowlands is the region north of Porta Westfalica in Germany, where the River Weser no longer flows through a valley, but a broad plain consisting of meadows and river terraces. The flat plain ...

Wittlich Depression The Wittlich Depression (german: Wittlicher Senke or ''Wittlicher Rotliegend-Senke''), less commonly, the Wittlich Basin, is the continuation of the Trier Valley in a northeasterly direction. It is not only recognisable in the terrain as an elon ...

* Wümme Depression

References

{{Geology-stub

Types

List of depressions

See also

References