In geology, a depression is a landform sunken or depressed below the surrounding area. Depressions form by various mechanisms.
Types
Erosion-related:
- Blowout: a depression created by wind erosion typically in either a partially vegetated sand dune ecosystem or dry soils (such as a post-glacial loess environment).
- Glacial valley: a depression carved by erosion by a glacier.
- River valley: a depression carved by fluvial erosion by a river.
- Area of subsidence caused by the collapse of an underlying structure, such as sinkholes in karst terrain.
- Sink: an endorheic depression generally containing a persistent or intermittent (seasonal) lake, a salt flat (playa) or dry lake, or an ephemeral lake.
- Panhole: a shallow depression or basin eroded into flat or gently sloping, cohesive rock.
Collapse-related:
- Sinkhole: a depression formed as a result of the collapse of rocks lying above a hollow. This is common in karst regions.
- Kettle: a shallow, sediment-filled body of water formed by melting glacial remnants in terminal moraines.
- Thermokarst hollow: caused by volume loss of the ground as the result of permafrost thawing.
Impact-related:
- Impact crater: a depression created by an impact, such as a meteorite crater.
Sedimentary-related:
- Sedimentary basin: in sedimentology, an area thickly filled with sediment 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 (the Hawaiian Trough is an example) or subduction (such as the Chilean Central Valley).
- Graben or rift valley: fallen and typically linear depressions or basins created by rifting in a region under tensional tectonic forces.
- Pull-apart basin caused by offset in a strike-slip or transform fault (example: the Dead Sea area).
- Oceanic trench: 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 beneath either the oceanic crust or continental crust.
- A basin formed by an ice sheet: an area depressed by the weight of the ice sheet resulting in post-glacial rebound after the ice melts (the area adjacent to the ice sheet may be pulled down to create a peripheral depression.)
Volcanism-related:
- Caldera: a volcanic depression resulting from collapse following a volcanic eruption.
- 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 depression resulting from phreatomagmatic eruption or diatreme explosion.
List of depressions
- Aral–Caspian Depression
- Baetic Depression
- Bodélé Depression
- Caspian Depression
- Danakil Depression
- Eider-Treene Depression
- Georgia Depression
- Giurgeu-Brașov Depression
- Godzareh Depression
- Huancabamba Depression
- Kara Depression
- Karashor Depression
- Kuma–Manych Depression
- Kuznetsk Depression
- Mari Depression
- Mourdi Depression
- Qattara Depression
- Regen Depression
- Ronda Depression
- Táchira Depression
- Tunkin Depression
- Turan Depression
- Turpan Depression
- Tuva Depression
- Upemba Depression
- Weser Depression
- Wittlich Depression
- Wümme Depression
See also
- Cryptodepression
- List of places on land with elevations below sea level
- Ponor
References
- "Dictionary of Geologic Terms – B". US Geochemical. Retrieved 2017-09-09.
- 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. doi:10.4000/geomorphologie.11880
- "Dictionary of Geologic Terms – K". US Geochemical. Retrieved 2017-09-09.
- "Glossary of Important Terms in Glacial Geology – Peripheral Depression". Montana State University. 1999. Archived from the original on 2006-08-29. Retrieved 2006-08-25. Cites American Geological Institute's Glossary of Geology (3rd edition, revised in 1987).
- "Dictionary of Geologic Terms – C". US Geochemical. Retrieved 2017-09-09.
In geology a depression is a landform sunken or depressed below the surrounding area Depressions form by various mechanisms A watering hole is a natural depression where water collects and animals come to drink Karst closed depression with permanent lake Stymfalia Peloponnese Greece Seasonal abundant precipitation drained by 3 sinkholesTypesErosion related Blowout a depression created by wind erosion typically in either a partially vegetated sand dune ecosystem or dry soils such as a post glacial loess environment Glacial valley a depression carved by erosion by a glacier River valley a depression carved by fluvial erosion by a river Area of subsidence caused by the collapse of an underlying structure such as sinkholes in karst terrain Sink an endorheic depression generally containing a persistent or intermittent seasonal lake a salt flat playa or dry lake or an ephemeral lake Panhole a shallow depression or basin eroded into flat or gently sloping cohesive rock Collapse related Sinkhole a depression formed as a result of the collapse of rocks lying above a hollow This is common in karst regions Kettle a shallow sediment filled body of water formed by melting glacial remnants in terminal moraines Thermokarst hollow caused by volume loss of the ground as the result of permafrost thawing Impact related Impact crater a depression created by an impact such as a meteorite crater Sedimentary related Sedimentary basin in sedimentology an area thickly filled with sediment 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 the Hawaiian Trough is an example or subduction such as the Chilean Central Valley Graben or rift valley fallen and typically linear depressions or basins created by rifting in a region under tensional tectonic forces Pull apart basin caused by offset in a strike slip or transform fault example the Dead Sea area Oceanic trench 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 beneath either the oceanic crust or continental crust A basin formed by an ice sheet an area depressed by the weight of the ice sheet resulting in post glacial rebound after the ice melts the area adjacent to the ice sheet may be pulled down to create a peripheral depression Volcanism related Caldera a volcanic depression resulting from collapse following a volcanic eruption 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 depression resulting from phreatomagmatic eruption or diatreme explosion List of depressionsAral Caspian Depression Baetic Depression Bodele Depression Caspian Depression Danakil Depression Eider Treene Depression Georgia Depression Giurgeu Brașov Depression Godzareh Depression Huancabamba Depression Kara Depression Karashor Depression Kuma Manych Depression Kuznetsk Depression Mari Depression Mourdi Depression Qattara Depression Regen Depression Ronda Depression Tachira Depression Tunkin Depression Turan Depression Turpan Depression Tuva Depression Upemba Depression Weser Depression Wittlich Depression Wumme DepressionSee alsoCryptodepression List of places on land with elevations below sea level PonorReferences Dictionary of Geologic Terms B US Geochemical Retrieved 2017 09 09 Twidale C R and Bourne J A 2018 Rock basins gnammas revisited Geomorphologie Relief Processus Environnement Vol 24 No 2 January 2018 Retrieved 9 June 2020 doi 10 4000 geomorphologie 11880 Dictionary of Geologic Terms K US Geochemical Retrieved 2017 09 09 Glossary of Important Terms in Glacial Geology Peripheral Depression Montana State University 1999 Archived from the original on 2006 08 29 Retrieved 2006 08 25 Cites American Geological Institute s Glossary of Geology 3rd edition revised in 1987 Dictionary of Geologic Terms C US Geochemical Retrieved 2017 09 09
