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 di ...

-related: *

Blowout Blowout or Blow out may refer to: Film and television *''Blow Out'', a 1981 film by Brian De Palma * ''The Blow Out'', a 1936 short film * ''Blow Out'' (TV series), a TV series on Bravo * "Blow Out" (''Prison Break''), an episode of ''Prison ...

: 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 A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...

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 di ...

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 a ...

. *

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 ov ...

: a depression carved by

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluv ...

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 ...

: 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 lar ...

, a salt flat (playa) or

dry lake A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...

, or an ephemeral lake. * 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 Glacier terminus, terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed ...

s. * Thermokarst hollow: caused by volume loss of the ground as the result of

permafrost Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surfac ...

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 A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object en ...

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 subsidence ...

: in

sedimentology Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation (erosion and weathering), transport, deposition and diagenesis. Sedimentologists apply their understanding of mo ...

, 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 structural basin is a large-scale structural formation of rock strata formed by tectonic warping of previously flat-lying strata. They are geological depressions, the inverse of domes. Elongated structural basins are also known as synclines ...

: a

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed ...

-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 it ...

(the Hawaiian Trough is an example) or subduction (such as the Chilean Central Valley). *

Graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...

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 de ...

: 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-grabe ...

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 In geology, a basin is a region where subsidence generates accommodation space for the deposition of sediments. A pull-apart basin is a structural basin where two overlapping (en echelon) strike-slip faults or a fault bend creates an area of cru ...

caused by offset in a

strike-slip In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tecton ...

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 subducti ...

(example: the

Dead Sea The Dead Sea ( he, יַם הַמֶּלַח, ''Yam hamMelaḥ''; ar, اَلْبَحْرُ الْمَيْتُ, ''Āl-Baḥrū l-Maytū''), also known by other names, is a salt lake bordered by Jordan to the east and Israel and the West Bank ...

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 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, ...

(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 ultramafi ...

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' ...

. * 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 ...

: 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 ...

: 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 ...

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 ...

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

Maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...

: 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 water ...

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 ...

* Baetic Depression * Bodélé Depression *

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 *

Eider-Treene Depression The Eider-Treene Depression (german: Eider-Treene-Niederung; da, Ejder-Trene-Sænkningen) is a landscape in west Schleswig-Holstein in North Germany. It covers around the rivers Eider, Treene and Sorge. The Eider-Treene Depression is the large ...

* Georgia Depression *

Giurgeu-Brașov Depression The Giurgeu-Brașov Depression (in Romanian, ''Depresiunea Giurgeu-Brașovului'') is a series of intermontane basins in Romania. The basin is considered part of the Inner Eastern Carpathians. Within Romania, however, it is traditional to divide ...

* Godzareh Depression * Huancabamba Depression * Kara Depression *

Karashor Depression The Karashor Depression (known as the "Black salt marsh") is a 120 kilometre long natural bowl in the northwest of Turkmenistan Turkmenistan ( or ; tk, Türkmenistan / Түркменистан, ) is a country located in Central Asia, border ...

* Kuma–Manych Depression *

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 Shori ...

* Mari Depression *

Mourdi Depression The Mourdi Depression is a prominent desert depression of northeastern Chad. It lies adjacent to the Ennedi Plateau. The cleft lies "between the Erdi plateau and the eastern slopes of Ennedi, and the mouth of the Wadi Guroguro." The depression i ...

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 Depress ...

Regen Depression The Regen Depression (german: Regensenke) is a wide river valley in the Bavarian Forest along the River Regen. As natural region major unit no. 404 the Regen Depression belongs to the Upper Palatine-Bavarian Forest and covers an area of 667 ...

Ronda Depression The Ronda Depression ( es, Depresión de Ronda; also ''Hoya de Ronda'' and occasionally ''Vega de Ronda'') is a sedimentary basin in the form of a plateau located within the Cordillera Penibética, in the autonomous community of Andalusia, Spain ...

* Táchira Depression * Tunkin Depression * Turan Depression *

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 include ...

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 ...

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 Kisa ...

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 ...

* Wittlich Depression *

Wümme Depression The Wümme Depression (german: Wümmeniederung) is a bog, geest and forest landscape within the Elbe–Weser triangle in the German state of Lower Saxony. It belongs mainly to the district of Rotenburg and is part of the Stade Geest. To the sou ...

References

{{Geology-stub

Types

List of depressions

See also

References