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A lake is an area filled with water, localized in a
basin Basin may refer to: Geography and geology * Depression (geology) ** Back-arc basin, a submarine feature associated with island arcs and subduction zones ** Debris basin, designed to prevent damage from debris flow ** Drainage basin (hydrology), ...
, surrounded by
land Land, also known as dry land, ground, or earth, is the solid terrestrial surface of the planet Earth that is not submerged by the ocean or other bodies of water. It makes up 29% of Earth's surface and includes the continents and various isl ...
, and distinct from any
river A river is a natural flowing watercourse, usually freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the ...
or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the
ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...
, although, like the much larger oceans, they do form part of the Earth's
water cycle The water cycle, also known as the hydrologic cycle or the hydrological cycle, is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly cons ...
. Lakes are distinct from
lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into '' coastal lagoons'' (or ''barrier lagoons' ...
s, which are generally coastal parts of the ocean. Lakes are typically larger and deeper than
pond A pond is an area filled with water, either natural or Artificiality, artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% Aquatic plant, emergent vegetation helps in disting ...
s, which also lie on land, though there are no official or scientific definitions. Lakes can be contrasted with
river A river is a natural flowing watercourse, usually freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the ...
s or streams, which usually flow in a channel on land. Most lakes are fed and drained by rivers and streams. Natural lakes are generally found in mountainous areas,
rift zone A rift zone is a feature of some volcanoes, especially shield volcanoes, in which a set of linear cracks (or rifts) develops in a volcanic edifice, typically forming into two or three well-defined regions along the flanks of the vent. Believed t ...
s, and areas with ongoing
glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate bet ...
. Other lakes are found in
endorheic basin An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into la ...
s or along the courses of mature rivers, where a river channel has widened into a basin. Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the last ice age. All lakes are temporary over long periods of time, as they will slowly fill in with sediments or spill out of the basin containing them. Many lakes are
artificial Artificiality (the state of being artificial or manmade) is the state of being the product of intentional human manufacture, rather than occurring nature, naturally through processes not involving or requiring human activity. Connotations Artific ...
and are constructed for industrial or agricultural use, for
hydroelectric power Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined a ...
generation or domestic water supply, for aesthetic or recreational purposes, or for other activities.


Etymology, meaning, and usage of "lake"

The word ''lake'' comes from
Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English ...
('lake, pond, waterway'), from Old English ('pond, pool, stream'), from
Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed proto-language of the Germanic branch of the Indo-European languages. Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic bran ...
('pond, ditch, slow moving stream'), from the
Proto-Indo-European Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo- ...
root ('to leak, drain'). Cognates include
Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People E ...
('lake, pond, ditch'),
Middle Low German Middle Low German or Middle Saxon (autonym: ''Sassisch'', i.e. "Saxon", Standard High German: ', Modern Dutch: ') is a developmental stage of Low German. It developed from the Old Saxon language in the Middle Ages and has been documented in ...
('water pooled in a riverbed, puddle') as in: :de:Wolfslake, :de:Butterlake,
German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...
('pool, puddle'), and Icelandic ('slow flowing stream'). Also related are the English words ''leak'' and ''leach''. There is considerable uncertainty about defining the difference between lakes and
pond A pond is an area filled with water, either natural or Artificiality, artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% Aquatic plant, emergent vegetation helps in disting ...
s, and neither term has an internationally accepted definition across scientific disciplines or political boundaries. For example,
limnologist Limnology ( ; from Greek λίμνη, ''limne'', "lake" and λόγος, ''logos'', "knowledge") is the study of inland aquatic ecosystems. The study of limnology includes aspects of the biological, chemical, physical, and geological characteris ...
s have defined lakes as water bodies that are simply a larger version of a pond, which can have wave action on the shoreline or where wind-induced turbulence plays a major role in mixing the water column. None of these definitions completely excludes ponds and all are difficult to measure. For this reason, simple size-based definitions are increasingly used to separate ponds and lakes. Definitions for ''lake'' range in minimum sizes for a body of water from to . Pioneering animal ecologist
Charles Elton Charles Elton may refer to: *Charles Elton (Born, 1993) Professional Rugby Player for Otago Rugby * Charles Isaac Elton (1839–1900), English lawyer, politician, writer and antiquarian * Charles Sutherland Elton (1900–1991), English biologist ...
regarded lakes as waterbodies of or more. The term ''lake'' is also used to describe a feature such as
Lake Eyre Lake Eyre ( ), officially known as Kati Thanda–Lake Eyre, is an endorheic lake in east-central Far North South Australia, some north of Adelaide. The shallow lake is the depocentre of the vast endorheic Lake Eyre basin, and contains ...
, which is a dry basin most of the time but may become filled under seasonal conditions of heavy rainfall. In common usage, many lakes bear names ending with the word ''pond'', and a lesser number of names ending with ''lake'' are, in quasi-technical fact, ponds. One textbook illustrates this point with the following: "In Newfoundland, for example, almost every lake is called a pond, whereas in Wisconsin, almost every pond is called a lake." One
hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...
book proposes to define the term "lake" as a body of water with the following five characteristics: # It partially or totally fills one or several basins connected by straits; # It has essentially the same water level in all parts (except for relatively short-lived variations caused by wind, varying ice cover, large inflows, etc.); # It does not have regular intrusion of
seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appr ...
; # A considerable portion of the
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 ...
suspended in the water is captured by the basins (for this to happen they need to have a sufficiently small inflow-to-volume ratio); # The area measured at the mean water level exceeds an arbitrarily chosen threshold (for instance, one
hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...
). With the exception of criterion 3, the others have been accepted or elaborated upon by other hydrology publications.


Distribution

The majority of lakes on Earth are
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does in ...
, and most lie in the Northern Hemisphere at higher
latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north po ...
s.
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...
, with a
deranged drainage system In geomorphology, drainage systems, also known as river systems, are the patterns formed by the streams, rivers, and lakes in a particular drainage basin. They are governed by the topography of land, whether a particular region is dominated by ha ...
, has an estimated 31,752 lakes larger than in surface area. The total number of lakes in Canada is unknown but is estimated to be at least 2 million.
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bo ...
has 187,888 lakes of in area, or larger, of which 56,000 are large ( or larger). Most lakes have at least one natural outflow in the form of a
river A river is a natural flowing watercourse, usually freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the ...
or stream, which maintain a lake's average level by allowing the drainage of excess water. Some lakes do not have a natural outflow and lose water solely by evaporation or underground seepage, or both. These are termed
endorheic An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into lakes ...
lakes. Many lakes are artificial and are constructed for hydroelectric power generation, aesthetic purposes,
recreation Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or ple ...
al purposes, industrial use,
agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...
use, or domestic
water supply Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. T ...
. The number of lakes on Earth is undetermined because most lakes and ponds are very small and do not appear on maps or satellite imagery. Despite this uncertainty, a large number of studies agree that small ponds are much more abundant than large lakes. For example, one widely cited study estimated that Earth has 304 million lakes and ponds, and that 91% of these are or less in area. Despite the overwhelming abundance of ponds, almost all of Earth's lake water is found in fewer than 100 large lakes; this is because lake volume
scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number ...
superlinearly with lake area. Extraterrestrial lakes exist on the moon
Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fiction ...
, which orbits the planet
Saturn Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; ...
. The shape of lakes on Titan is very similar to those on Earth. Lakes were formerly present on the surface of Mars, but are now
dry lake bed 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 ...
s.


Types

In 1957,
G. Evelyn Hutchinson George Evelyn Hutchinson (January 30, 1903 – May 17, 1991) was a British ecologist sometimes described as the "father of modern ecology." He contributed for more than sixty years to the fields of limnology, systems ecology, radiation ecolog ...
published a monograph titled ''A Treatise on Limnology'', which is regarded as a landmark discussion and classification of all major lake types, their origin, morphometric characteristics, and distribution. Hutchinson presented in his publication a comprehensive analysis of the origin of lakes and proposed what is a widely accepted classification of lakes according to their origin. This classification recognizes 11 major lake types that are divided into 76 subtypes. The 11 major lake types are: * tectonic lakes * volcanic lakes * glacial lakes * fluvial lakes * solution lakes * landslide lakes * aeolian lakes * shoreline lakes * organic lakes * anthropogenic lakes * meteorite (extraterrestrial impact) lakes


Tectonic lakes

Tectonic lakes are lakes formed by the deformation and resulting lateral and vertical movements of the Earth's crust. These movements include faulting, tilting, folding, and warping. Some of the largest lakes on Earth are
rift lake A rift lake is a lake formed as a result of subsidence related to movement on faults within a rift zone, an area of extensional tectonics in the continental crust. They are often found within rift valleys and may be very deep. Rift lakes may be ...
s occupying rift valleys, e.g. Central African Rift lakes and
Lake Baikal Lake Baikal (, russian: Oзеро Байкал, Ozero Baykal ); mn, Байгал нуур, Baigal nuur) is a rift lake in Russia. It is situated in southern Siberia, between the Federal subjects of Russia, federal subjects of Irkutsk Oblast, I ...
. Other well-known tectonic lakes,
Caspian Sea The Caspian Sea is the world's largest inland body of water, often described as the List of lakes by area, world's largest lake or a full-fledged sea. An endorheic basin, it lies between Europe and Asia; east of the Caucasus, west of the broad s ...
, the
Sea of Aral The Aral Sea ( ; kk, Арал теңізі, Aral teñızı; uz, Орол денгизи, Orol dengizi; kaa, Арал теңизи, Aral teńizi; russian: Аральское море, Aral'skoye more) was an endorheic lake lying between Kazakh ...
, and other lakes from the Pontocaspian occupy basins that have been separated from the sea by the tectonic uplift of the sea floor above the ocean level. Often, the tectonic action of crustal extension has created an alternating series of parallel
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 ...
s and horsts that form elongate basins alternating with mountain ranges. Not only does this promote the creation of lakes by the disruption of preexisting drainage networks, it also creates within arid regions
endorheic basin An endorheic basin (; also spelled endoreic basin or endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but drainage converges instead into la ...
s that contain
salt lakes A salt lake or saline lake is a landlocked body of water that has a concentration of salts (typically sodium chloride) and other dissolved minerals significantly higher than most lakes (often defined as at least three grams of salt per litre). ...
(also called
saline Saline may refer to: * Saline (medicine), a liquid with salt content to match the human body * Saline water, non-medicinal salt water * Saline, a historical term (especially US) for a salt works or saltern Places * Saline, Calvados, a commune in ...
lakes). They form where there is no natural outlet, a high evaporation rate and the drainage surface of the
water table The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated. Th ...
has a higher-than-normal
salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quanti ...
content. Examples of these salt lakes include Great Salt Lake and 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 ...
. Another type of tectonic lake caused by faulting is
sag pond A sag pond is a body of fresh water collected in the lowest parts of a depression formed between two sides of an active strike-slip, transtensional or normal fault zone. Formation A sag pond is formed along a strike-slip fault, which may creat ...
s.


Volcanic lakes

Volcanic lakes are lakes that occupy either local depressions, e.g. craters and
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 ...
s, or larger basins, e.g.
calderas 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 ...
, created by
volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the Earth#Surface, surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the su ...
.
Crater lake Crater Lake (Klamath: ''Giiwas'') is a volcanic crater lake in south-central Oregon in the western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity. The lake partly fills ...
s are formed in
volcanic crater A volcanic crater is an approximately circular depression in the ground caused by volcanic activity. It is typically a bowl-shaped feature containing one or more vents. During volcanic eruptions, molten magma and volcanic gases rise from an und ...
s and calderas, which fill up with precipitation more rapidly than they empty via either evaporation, groundwater discharge, or a combination of both. Sometimes the latter are called caldera lakes, although often no distinction is made. An example is
Crater Lake Crater Lake (Klamath: ''Giiwas'') is a volcanic crater lake in south-central Oregon in the western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity. The lake partly fills ...
in
Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idah ...
, in the caldera of
Mount Mazama Mount Mazama (''Giiwas'' in the Native American language Klamath) is a complex volcano in the state of Oregon, United States, in a segment of the Cascade Volcanic Arc and Cascade Range. Most of the mountain collapsed following a major erupti ...
. The caldera was created in a massive volcanic eruption that led to the subsidence of
Mount Mazama Mount Mazama (''Giiwas'' in the Native American language Klamath) is a complex volcano in the state of Oregon, United States, in a segment of the Cascade Volcanic Arc and Cascade Range. Most of the mountain collapsed following a major erupti ...
around 4860 BCE. Other volcanic lakes are created when either rivers or streams are dammed by
lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...
s or volcanic
lahar A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are extreme ...
s. The basin which is now
Malheur Lake Malheur Lake is one of the lakes in the Malheur National Wildlife Refuge in Harney County in the U.S. state of Oregon. Located about southeast of Burns, the lake is marsh fed by the Donner und Blitzen River from the south and the Silvies River ...
,
Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idah ...
was created when a lava flow dammed the
Malheur River The Malheur River (local pronunciation: "MAL-hyure") is a tributary of the Snake River in eastern Oregon in the United States. It drains a high desert area, between the Harney Basin and the Blue Mountains and the Snake. Despite the similarit ...
. Among all lake types, volcanic crater lakes most closely approximate a circular shape.


Glacial lakes

Glacial lakes are lakes created by the direct action of glaciers and continental ice sheets. A wide variety of glacial processes create enclosed basins. As a result, there are a wide variety of different types of glacial lakes and it is often difficult to define clear-cut distinctions between different types of glacial lakes and lakes influenced by other activities. The general types of glacial lakes that have been recognized are lakes in direct contact with ice, glacially carved rock basins and depressions, morainic and outwash lakes, and glacial drift basins. Glacial lakes are the most numerous lakes in the world. Most lakes in northern Europe and North America have been either influenced or created by the latest, but not last, glaciation, to have covered the region. Glacial lakes include
proglacial lake In geology, a proglacial lake is a lake formed either by the damming action of a moraine during the retreat of a melting glacier, a glacial ice dam, or by meltwater trapped against an ice sheet due to isostatic depression of the crust around th ...
s,
subglacial lake A subglacial lake is a lake that is found under a glacier, typically beneath an ice cap or ice sheet. Subglacial lakes form at the boundary between ice and the underlying bedrock, where gravitational pressure decreases the pressure melting poin ...
s,
finger lake A finger lake, also known as a fjord lake or trough lake, is "a narrow linear body of water occupying a glacially overdeepened valley and sometimes impounded by a morainic dam."Kotlyakov and Komarova (2007), 255. Where one end of a finger lake ...
s, and epishelf lakes. Epishelf lakes are highly stratified lakes in which a layer of freshwater, derived from ice and snow melt, is dammed behind an
ice shelf An ice shelf is a large floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland, Northern Canada, and the Russian Arctic. Th ...
that is attached to the coastline. They are mostly found in Antarctica.


Fluvial lakes

Fluvial (or riverine) lakes are lakes produced by running water. These lakes include plunge pool lakes, fluviatile dams and meander lakes.


Oxbow lakes

The most common type of fluvial lake is a crescent-shaped lake called an ''
oxbow lake An oxbow lake is a U-shaped lake or pool that forms when a wide meander of a river is cut off, creating a free-standing body of water. In South Texas, oxbows left by the Rio Grande are called '' resacas''. In Australia, oxbow lakes are cal ...
'' due to the distinctive curved shape. They can form in river valleys as a result of meandering. The slow-moving river forms a sinuous shape as the outer side of bends are eroded away more rapidly than the inner side. Eventually a horseshoe bend is formed and the river cuts through the narrow neck. This new passage then forms the main passage for the river and the ends of the bend become silted up, thus forming a bow-shaped lake. Their crescent shape gives oxbow lakes a higher perimeter to area ratio than other lake types.


Fluviatile dams

These form where sediment from a tributary blocks the main river.


Lateral lakes

These form where sediment from the main river blocks a tributary, usually in the form of a
levee A levee (), dike (American English), dyke (Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually earthen and that often runs parallel to the course of a river in its floodplain or along low-lying coastl ...
.


Floodplain lakes

Lakes formed by other processes responsible for
floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...
basin creation. During high floods they are flushed with river water. There are four types: 1. Confluent floodplain lake, 2. Contrafluent-confluent floodplain lake, 3. Contrafluent floodplain lake, 4. Profundal floodplain lake.


Solution lakes

A solution lake is a lake occupying a basin formed by surface dissolution of bedrock. In areas underlain by soluble bedrock, its solution by precipitation and percolating water commonly produce cavities. These cavities frequently collapse to form
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 that form part of the local
karst topography Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ...
. Where
groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidat ...
lies near the grounds surface, a sinkhole will be filled water as a solution lake. If such a lake consists of a large area of standing water that occupies an extensive closed depression in limestone, it is also called a
karst lake Karst lakes are formed as the result of a collapse of caves, especially in water-soluble rocks such as limestone, gypsum and dolomite. This process is known as karstification. They can cover areas of several 100 square kilometres. Their shallow l ...
. Smaller solution lakes that consist of a body of standing water in a closed depression within a karst region are known as ''karst ponds.''Neuendorf, K.K.E., Mehl Jr., J.P., and Jackson, J.A. (2005). ''Glossary of Geology,'' 5th revised and enlarged ed. Berlin: Springer. Approx. . Limestone caves often contain pools of standing water, which are known as ''
underground lake An underground lake or subterranean lake is a lake underneath the surface of the Earth. Most naturally occurring underground lakes are found in areas of Karst topography, where limestone or other soluble rock has been weathered away, leaving a ca ...
s.'' Classic examples of solution lakes are abundant in the karst regions at the
Dalmatian coast Dalmatia (; hr, Dalmacija ; it, Dalmazia; see names in other languages) is one of the four historical regions of Croatia, alongside Croatia proper, Slavonia, and Istria. Dalmatia is a narrow belt of the east shore of the Adriatic Sea, stret ...
of
Croatia , image_flag = Flag of Croatia.svg , image_coat = Coat of arms of Croatia.svg , anthem = "Lijepa naša domovino"("Our Beautiful Homeland") , image_map = , map_caption = , capit ...
and within large parts of
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...
.


Landslide lakes

A landslide lake is created by the
blockage ''Blockage'' ( Persian: سد معبر, romanized: Sade Ma'bar) is a 2017 Iranian drama film directed by Mohsen Gharaie and written by Saeed Roustayi. The film screened for the first time at the 35th Fajr Film Festival and received 4 nominations. ...
of 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 ...
by either
mudflow A mudflow or mud flow is a form of mass wasting involving fast-moving flow of debris that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/second. Mudflows contain a significa ...
s,
rockslide A rockslide is a type of landslide caused by rock failure in which part of the bedding plane of failure passes through compacted rock and material collapses ''en masse'' and not in individual blocks. Note that a rockslide is similar to an avalanc ...
s, or
scree Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. Talus deposits typically ha ...
s. Such lakes are most common in mountainous regions. Although landslide lakes may be large and quite deep, they are typically short-lived. An example of a landslide lake is
Quake Lake Quake Lake (officially Earthquake Lake) is a lake in the western United States, on the Madison River in southwestern Montana. It was created after an earthquake struck on August 17, 1959, with 28 fatalities. Northwest of West Yellowstone, Qua ...
, which formed as a result of the
1959 Hebgen Lake earthquake The 1959 Hebgen Lake earthquake (also known as the 1959 Yellowstone earthquake) occurred in the western United States on August 17 at 11:37 pm ( MST) in southwestern Montana. The earthquake measured 7.2 on the moment magnitude scale, caused a hu ...
. Most landslide lakes disappear in the first few months after formation, but a landslide dam can burst suddenly at a later stage and threaten the population downstream when the lake water drains out. In 1911, an earthquake triggered a landslide that blocked a deep valley in the
Pamir Mountains The Pamir Mountains are a mountain range between Central Asia and Pakistan. It is located at a junction with other notable mountains, namely the Tian Shan, Karakoram, Kunlun, Hindu Kush and the Himalaya mountain ranges. They are among the worl ...
region of
Tajikistan Tajikistan (, ; tg, Тоҷикистон, Tojikiston; russian: Таджикистан, Tadzhikistan), officially the Republic of Tajikistan ( tg, Ҷумҳурии Тоҷикистон, Jumhurii Tojikiston), is a landlocked country in Centr ...
, forming the
Sarez Lake Sarez Lake (russian: Сарезское озеро; tg, Сарез кӯл, Sarez Kūl) is a lake in Rushon District of Gorno-Badakhshan province, Tajikistan. Length about , depth few hundred meters, water surface elevation about above sea lev ...
. The
Usoi Dam The Usoi Dam is a natural landslide dam along the Murghab River in Tajikistan. At high, it is the tallest dam in the world, either natural or man-made. The dam was created on February 18, 1911, when the 7.4- Ms Sarez earthquake caused a massive ...
at the base of the valley has remained in place for more than 100 years but the terrain below the lake is in danger of a catastrophic flood if the dam were to fail during a future earthquake.
Tal-y-llyn Lake Tal-y-llyn Lake, ( cy, Llyn Mwyngil), also known as Talyllyn Lake and Llyn Myngul, is a large glacial ribbon lake in Gwynedd, North Wales. It is formed by a post-glacial massive landslip damming up the lake within the glaciated valley. The haml ...
in north
Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
is a landslide lake dating back to the last glaciation in Wales some 20000 years ago.


Aeolian lakes

Aeolian lakes are produced by wind action. These lakes are found mainly in
arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...
environments, although some aeolian lakes are
relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...
landforms indicative of arid
paleoclimate Paleoclimatology ( British spelling, palaeoclimatology) is the study of climates for which direct measurements were not taken. As instrumental records only span a tiny part of Earth's history, the reconstruction of ancient climate is important t ...
s. Aeolian lakes consist of lake basins dammed by wind-blown sand; interdunal lakes that lie between well-oriented
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 ...
s; and deflation basins formed by wind action under previously arid paleoenvironments.
Moses Lake Moses Lake is a lake and reservoir along the course of Crab Creek, in Washington state, USA. Moses Lake is part of the Columbia River basin, as Crab Creek is a tributary of the Columbia River. Although originally a shallow natural lake, Mose ...
in
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...
, United States, was originally a shallow natural lake and an example of a lake basin dammed by wind-blown sand. China's
Badain Jaran Desert The Badain Jaran Desert () is a desert in China which spans the provinces of Gansu, Ningxia and Inner Mongolia. It covers an area of . By size it is the third largest desert in China. This desert is home to some of the tallest stationary dunes ...
is a unique landscape of megadunes and elongated interdunal aeolian lakes, particularly concentrated in the southeastern margin of the desert.


Shoreline lakes

Shoreline lakes are generally lakes created by blockage of estuaries or by the uneven accretion of beach ridges by longshore and other currents. They include maritime coastal lakes, ordinarily in drowned estuaries; lakes enclosed by two tombolos or spits connecting an island to the mainland; lakes cut off from larger lakes by a bar; or lakes divided by the meeting of two spits.


Organic lakes

Organic lakes are lakes created by the actions of plants and animals. On the whole they are relatively rare in occurrence and quite small in size. In addition, they typically ephemeral features relative to the other types of lakes. The basins in which organic lakes occur are associated with beaver dams, coral lakes, or dams formed by vegetation.


Peat lakes

Peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...
lakes are a form of organic lake. They form where a buildup of partly decomposed plant material in a wet environment leaves the vegetated surface below the
water table The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated. Th ...
for a sustained period of time. They are often low in nutrients and mildly acidic, with bottom waters low in dissolved oxygen.


Anthropogenic lakes

Anthropogenic lakes are artificially created as a result of human activity. They can be formed by the intentional damming of rivers and streams or the subsequent filling of abandoned excavations by either ground water, precipitation, or a combination of both. The
Upper Silesia Upper Silesia ( pl, Górny Śląsk; szl, Gůrny Ślůnsk, Gōrny Ślōnsk; cs, Horní Slezsko; german: Oberschlesien; Silesian German: ; la, Silesia Superior) is the southeastern part of the historical and geographical region of Silesia, locate ...
n region of Southern Poland contains an anthropogenic lake district consisting of more than 4,000 water bodies created by human activity. The diverse origins of these lakes include: reservoirs retained by dams, flooded mines, water bodies formed in subsidence basins and hollows,
levee A levee (), dike (American English), dyke (Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually earthen and that often runs parallel to the course of a river in its floodplain or along low-lying coastl ...
ponds, and residual water bodies following river regulation.


Meteorite (extraterrestrial impact) lakes

Meteorite lakes, also known as ''crater lakes'' (not to be confused with
volcanic crater lakes 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 ar ...
), are created by catastrophic impacts with the Earth by extraterrestrial objects (either
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 ...
s or
asteroid An asteroid is a minor planet of the Solar System#Inner solar system, inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic o ...
s). Examples of meteorite lakes are
Lonar Lake Lonar Lake, also known as Lonar crater, is a notified National Geo-heritage Monument,
Lake El'gygytgyn Lake El'gygytgyn ( Russian and Chukchi: Эльгыгытгын) is an impact crater lake located in the Chukotka Autonomous Okrug in northeast Siberia, about southeast of Chaunskaya Bay. The word "Elgygytgyn" means "white lake" in the Chukchi ...
in northeast Siberia, and the
Pingualuit crater The Pingualuit Crater (french: Cratère des Pingualuit; from Inuit "pimple"), formerly called the "Chubb Crater" and later the "New Quebec Crater" (french: Cratère du Nouveau-Québec), is a relatively young impact crater located on the Ungava Pe ...
lake in Quebec, Canada. As in the cases of El'gygytgyn and Pingualuit, meteorite lakes can contain unique and scientifically valuable sedimentary deposits associated with long records of paleoclimatic changes.


Other classification methods

In addition to the mode of origin, lakes have been named and classified according to various other important factors such as
thermal stratification Lake stratification is the tendency of lakes to form separate and distinct thermal layers during warm weather. Typically stratified lakes show three distinct layers, the Epilimnion comprising the top warm layer, the thermocline (or Metalimnion): ...
, oxygen saturation, seasonal variations in lake volume and water level,
salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
of the water mass, relative seasonal permanence, degree of outflow, and so on. The names used by the lay public and in the scientific community for different types of lakes are often informally derived from the morphology of the lakes' physical characteristics or other factors. Also, different cultures and regions of the world have their own popular nomenclature.


By thermal stratification

One important method of lake classification is on the basis of thermal stratification, which has a major influence on the animal and plant life inhabiting a lake, and the fate and distribution of dissolved and suspended material in the lake. For example, the thermal stratification, as well as the degree and frequency of mixing, has a strong control over the distribution of oxygen within the lake. Professor F.-A. Forel,Forel, F.A., 1901. ''Handbuch der Seenkunde. Allgemeine Limnologie.'' J. von Engelhorn, Stuttgart, Germany. also referred to as the "Father of limnology", was the first scientist to classify lakes according to their thermal stratification. His system of classification was later modified and improved upon by Hutchinson and Löffler. As the
density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...
of water varies with temperature, with a maximum at +4 degrees Celsius, thermal stratification is an important physical characteristic of a lake that controls the
fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as ''biota''. Zoo ...
and
flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...
, sedimentation, chemistry, and other aspects of individual lakes. First, the colder, denser water typically forms a layer near the bottom, which is called the ''
hypolimnion The hypolimnion or under lake is the dense, bottom layer of water in a thermally- stratified lake. The word hypolimnion is derived from the Greek "limnos" meaning "lake". It is the layer that lies below the thermocline. Typically the hypolimnio ...
''. Second, normally overlying the hypolimnion is a transition zone known as the ''
metalimnion A thermocline (also known as the thermal layer or the metalimnion in lakes) is a thin but distinct layer in a large body of fluid (e.g. water, as in an ocean or lake; or air, e.g. an atmosphere) in which temperature changes more drastically with ...
''. Finally, overlying the metalimnion is a surface layer of warmer water with a lower density, called the ''
epilimnion The epilimnion or surface layer is the top-most layer in a thermally stratified lake. It sits above the deeper metalimnion and hypolimnion. It is typically warmer and has a higher pH and higher dissolved oxygen concentration than the hypolimni ...
''. This typical stratification sequence can vary widely, depending on the specific lake or the time of year, or a combination of both. The classification of lakes by thermal stratification presupposes lakes with sufficient depth to form a hypolimnion; accordingly, very shallow lakes are excluded from this classification system. Based upon their thermal stratification, lakes are classified as either ''
holomictic Holomictic lakes are lakes that have a uniform temperature and density from surface to bottom at a specific time during the year, which allows the lake waters to mix in the absence of stratification. Details Holomictic lakes mix at least occas ...
'', with a uniform temperature and density from top to bottom at a given time of year, or ''
meromictic A meromictic lake is a lake which has layers of water that do not intermix. In ordinary, holomictic lakes, at least once each year, there is a physical mixing of the surface and the deep waters. The term ''meromictic'' was coined by the Austri ...
'', with layers of water of different temperature and density that do not intermix. The deepest layer of water in a meromictic lake does not contain any dissolved oxygen so there are no living
aerobic organism Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of ...
s. Consequently, the layers of sediment at the bottom of a meromictic lake remain relatively undisturbed, which allows for the development of
lacustrine deposits Lacustrine deposits are sedimentary rock formations which formed in the bottom of ancient lakes. A common characteristic of lacustrine deposits is that a river or stream channel has carried sediment into the basin. Lacustrine deposits form in all ...
. In a holomictic lake, the uniformity of temperature and density allows the lake waters to completely mix. Based upon thermal stratification and frequency of turnover, holomictic lakes are divided into
amictic lake Amictic lakes are "perennially sealed off by ice, from most of the annual seasonal variations in temperature." Amictic lakes exhibit inverse cold water stratification whereby water temperature increases with depth below the ice surface 0 °C ( ...
s, cold
monomictic lake Monomictic lakes are holomictic lakes that mix from top to bottom during one mixing period each year. Monomictic lakes may be subdivided into cold and warm types. Cold monomictic lakes Cold monomictic lakes are lakes that are covered by ice thro ...
s,
dimictic lake A dimictic lake is a body of freshwater whose difference in temperature between surface and bottom layers becomes negligible twice per year, allowing all strata of the lake's water to circulate vertically. All dimictic lakes are also considered ho ...
s, warm monomictic lakes,
polymictic lake Polymictic lakes are holomictic lakes that are too shallow to develop thermal stratification; thus, their waters can mix from top to bottom throughout the ice-free period. Polymictic lakes can be divided into cold polymictic lakes (i.e., those tha ...
s, and oligomictic lakes. Lake stratification does not always result from a variation in density because of thermal gradients.
Stratification Stratification may refer to: Mathematics * Stratification (mathematics), any consistent assignment of numbers to predicate symbols * Data stratification in statistics Earth sciences * Stable and unstable stratification * Stratification, or str ...
can also result from a density variation caused by gradients in salinity. In this case, the hypolimnion and epilimnion are separated not by a thermocline but by a ''
halocline In oceanography, a halocline (from Greek ''hals'', ''halos'' 'salt' and ''klinein'' 'to slope') is a cline, a subtype of chemocline caused by a strong, vertical salinity gradient within a body of water. Because salinity (in concert with temper ...
'', which is sometimes referred to as a ''
chemocline A chemocline is a type of cline, a layer of fluid with different properties, characterized by a strong, vertical chemistry gradient within a body of water. In bodies of water where chemoclines occur, the cline separates the upper and lower layer ...
''.


By seasonal variations in water level and volume

Lakes are informally classified and named according to the seasonal variation in their lake level and volume. Some of the names include: * Ephemeral lake is a short-lived lake or pond. If it fills with water and dries up (disappears) seasonally it is known as an ''intermittent lake''Poehls, D.J. and Smith, G.J. eds. (2009). ''Encyclopedic dictionary of hydrogeology.'' Academic Press. p. 517. They often fill
polje A polje, also karst polje or karst field, is a large flat plain found in karstic geological regions of the world, with areas usually . The name derives from the Slavic languages and literally means 'field', whereas in English ''polje'' specifi ...
s. *
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 ...
is a popular name for an ephemeral lake that contains water only intermediately at irregular and infrequent intervals.Last, W.M. and Smol, J.P. (2001). ''Tracking environmental change using lake sediments. Volume 1: basin analysis, coring, and chronological techniques.'' Springer Science & Business Media. * Perennial lake is a lake that has water in its basin throughout the year and is not subject to extreme fluctuations in level.Gangstad, E.O., (1979)
''Glossary of Biolimnological Terms''
Washington, DC, United States Army Corps of Engineers.
* Playa lake is a typically shallow, intermittent lake that covers or occupies a playa either in wet seasons or in especially wet years but subsequently drying up in an arid or semiarid region. *
Vlei A vlei () is a shallow minor lake, mostly of a seasonal or intermittent nature. It even might refer to seasonal ponds or marshy patches where frogs and similar marsh dwellers breed. Commonly, vleis vary in their extent, or even in the presence ...
is a name used in
South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...
for a shallow lake which varies considerably in level with the seasons.Theal, G.M., 1877. ''Compendium of South African history and geography, 3rd.'' Institution Press, Lovedale, South Africa.


By water chemistry

Lakes may be informally classified and named according to the general chemistry of their water mass. Using this classification method, the lake types include: * An ''acid lake'' contains water with a below-neutral pH of less than 6.5. A lake is considered to be highly acidic if its pH drops below 5.5, leading to biological consequences. Such lakes include: acidic ''pit lakes'' occupying abandoned mines and excavations; naturally acidic lakes of
igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma o ...
and
metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, cau ...
landscapes;
peat bogs A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; ...
in northern regions; ''crater lakes'' of active and dormant volcanoes; and lakes acidified by acid rain.Geller, W. et al. (eds.) (2013). ''Acidic Pit Lakes, Environmental Science and Engineering'', Springer-Verlag Berlin HeidelbergRouwet, D. et al. (eds.) (2015). ''Volcanic Lakes, Advances in Volcanology,'' Springer-Verlag Berlin Heidelberg * A ''salt lake'', also known as a ''saline lake'' or ''brine lake'', is an inland body of water situated in an arid or semiarid region, with no outlet to the sea, containing a high concentration of dissolved neutral salts (principally
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35 ...
). Examples include the Great Salt Lake in Utah, and the Dead Sea in southwestern Asia. * An ''
alkali sink An alkali sink is a salty basin land form. The term may also refer to a North American desert vegetation type (biome) characteristic of that landform.Pam MacKay, Mojave Desert Wildflowers, 2nd Ed., p. 15-16 Rainwater drains to the basin and collec ...
'', also known as an ''alkali flat'' or ''salt flat'', is a shallow saline feature that can be found in low-lying areas of arid regions and in groundwater discharge zones. These features are typically classified as ''dry lakes'', or ''playas'', because they are periodically flooded by rain or flood events and then dry up during drier intervals, leaving accumulations of brines and evaporitic minerals. * A '' salt pan'' is a small shallow natural depression in which water accumulates and evaporates, leaving a salt deposit, or the shallow lake of
brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...
that occupies a salt pan. (The term "salt pan" comes from
open-pan salt making Open-pan salt making is a method of salt production wherein salt is extracted from brine using open pans. Virtually all European domestic salt is obtained by solution-mining of underground salt formations, although some is still obtained by t ...
, a method of extracting salt from brine using large open pans.) * A ''saline pan'' is another name for an
ephemeral acid saline lake An ephemeral acid saline lake is a lake that is relatively high in dissolved salts and has a low pH, usually within the range of 25%, nearly 8 times that of seawater. Most of the Western Australian waters are sodium chloride (NaCl) brines with var ...
which precipitates a bottom crust that is subsequently modified during subaerial exposure.


Composed of other liquids

*
Lava lake Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified (someti ...
is a large volume of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. * Hydrocarbon lakes are bodies of liquid
ethane Ethane ( , ) is an organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petro ...
and
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ear ...
that occupy depressions on the surface of
Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fiction ...
. They were detected by the Cassini–Huygens space probe.


Paleolakes

A paleolake (also palaeolake) is a lake that existed in the past when hydrological conditions were different. Quaternary paleolakes can often be identified on the basis of
relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...
lacustrine landforms, such as relict lake plains and coastal landforms that form recognizable relict shorelines called ''
paleoshorelines A paleoshoreline (ancient shoreline) is a shoreline which existed in the geologic past. (''Paleo'' is from an ancient Greek word meaning "old" or "ancient".) A perched coastline is an ancient (fossil) shoreline positioned above the present sho ...
.'' Paleolakes can also be recognized by characteristic
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