An ice volcano is a conical mound of ice formed over a terrestrial lake via the eruption of water and slush through an ice shelf. The process is wave-driven, with wind providing the energy for the waves to cut through the ice and form the volcanoes. After being ejected into the atmosphere, the liquid water and slush freeze and fall back to the surface, growing the formation. Ice may also be erupted. The phenomenon is most often observed along the southern coast of Lake Erie and Lake Ontario, when the temperature is below freezing and the wind blows onshore with a velocity of at least 25 mph (40 km/h). They are known to reduce coastal erosion there. The formations are temporary — they are frequently destroyed by storms and warm weather, and once the lake wholly freezes over, eruptions are no longer possible.
There is no consensus name for this phenomenon. Due to its similarity to volcanism and particularly cryovolcanism, the term "ice volcano" is frequently used, but it remains controversial. Unlike geysers and related structures, ice volcanoes are not hydrothermal.
The uplifts may attract a number of visitors, but they are dangerous, and experts warn that people may fall through the ice or slip into the cold lake. Ice volcanoes are used by snowy owls as hunting platforms to search for waterfowl.
These features are distinct from pressure ridges, which are uplifts formed by the compression of ice against a shoreline or another floe. Instead, ice volcanoes are created by waves colliding with irregularities at the edge of an ice sheet. The abnormalities concentrate the wave energy in a small area, where the ice is eroded to form a V-shaped channel. Spray, ice, and slush splashing out of the feature create a volcanic cone at the channel's shoreward end. This process takes only a few hours. The lakeward end of the channel may then by sealed by ice, but the volcano may continue to erupt. A wave amplitude of at least one metre (3 ft 3 in) is needed to induce eruptions, so ice volcanoes are rarely active without storm-force winds. Formation near land is suppressed by reefs and shoals, which absorb the wave energy needed for the phenomenon. Nonetheless, they may produce larger cones further out at sea, where the greater depth makes this possible. Formation is more thoroughly suppressed by powerful storms, which erode the ice too fast for mound creation.
One type of ice volcano, known as a cold spot, does not require waves to break against the edge of an ice shelf. Instead, water and slush erupt through a region of weak ice near the coast and form a mound. This is analogous to a geological hotspot.
Landfast ice is required, so the volcanoes normally form near land. They are found in successive rows, and within one row, the features usually have equal height and spacing. However, when comparing two rows, the height and spacing may be drastically different. Ice volcanoes range in height from less than one meter to ten meters, with the largest ones located far from the shore. Eruptions over ten meters high have been observed, but it is believed that the height of the eruptions are proportional to the size of the mounds. A single eruption may increase the height of the volcano by several centimeters. When an eruption occurs above 0 °C, however, the water erodes the uplift instead of expanding it. Spacing is determined by the amplitude and direction of the waves. In general, the appearance and number of ice volcanoes change considerably between winters.
Different types of ice volcanoes have been compared to shield volcanoes and stratovolcanoes. They are noted for their symmetry. Cold spot volcanoes are particularly symmetrical, but their eruption has not been observed.
Ahuna Mons () is the largest mountain on the dwarf planet and asteroid Ceres. It protrudes above the cratered terrain, is not an impact feature, and is the only mountain of its kind on Ceres. Bright streaks run top to bottom on its slopes; these streaks are thought to be salt, similar to the better known Cererian bright spots, and likely resulted from cryovolcanic activity from Ceres's interior. It is named after the traditional post-harvest festival Ahuna of the Sumi Naga people of India. In July 2018, NASA released a comparison of physical features, including Ahuna Mons, found on Ceres with similar ones present on Earth.Berry Glacier
Berry Glacier (75°S 134°W) is an Antarctic glacier, about 25 miles (40 km) long and 5 miles (8 km) wide, draining north between Perry Range and Demas Range into the Getz Ice Shelf on the coast of Marie Byrd Land. This vicinity was first photographed and rudely charted from aircraft of the U.S. Antarctic Service in December 1940, and the glacier was mapped in detail by the U.S. Geological Survey from ground surveys and from U.S. Navy air photos, 1959–66. It was named by the Advisory Committee on Antarctic Names for Commander William H. Berry, U.S. Navy, Air Operations Officer for Task Force 43 during Operation Deep Freeze 1969–72; Operations Officer, 1973.There are seven volcanic nunataks along the east side of the glacier.Ceres (dwarf planet)
Ceres (; minor-planet designation: 1 Ceres) is the largest object in the main asteroid belt that lies between the orbits of Mars and Jupiter. With a diameter of 945 km (587 mi), Ceres is both the largest of the asteroids and the only unambiguous dwarf planet inside Neptune's orbit. It is the 25th-largest body in the Solar System within the orbit of Neptune.Ceres is the only object in the asteroid belt known to be currently rounded by its own gravity, although detailed analysis was required to exclude Vesta. From Earth, the apparent magnitude of Ceres ranges from 6.7 to 9.3, peaking once at opposition every 15 to 16 months, which is its synodic period. Thus even at its brightest, it is too dim to be seen by the naked eye, except under extremely dark skies.
Ceres was the first asteroid to be discovered (by Giuseppe Piazzi at Palermo Astronomical Observatory on 1 January 1801). It was originally considered a planet, but was reclassified as an asteroid in the 1850s after many other objects in similar orbits were discovered.
Ceres appears to be partially differentiated into a muddy (ice-rock) mantle, with a crust that is 60 percent rock and 40 percent ice or less than 30 percent ice. It probably no longer has an internal ocean of liquid water, but there is brine that can flow through the outer mantle and reach the surface. The surface is a mixture of water ice and various hydrated minerals such as carbonates and clay. Cryovolcanoes such as Ahuna Mons form at the rate of about one every fifty million years. In January 2014, emissions of water vapor were detected from several regions of Ceres. This was unexpected because large bodies in the asteroid belt typically do not emit vapor, a hallmark of comets. Any atmosphere, however, would be the minimal kind known as an exosphere.The robotic NASA spacecraft Dawn entered orbit around Ceres on 6 March 2015.Cold spot
Cold spot may refer to:
Cold spot (paranormal), an area of low temperature that allegedly indicates the presence of a ghost
CMB cold spot, a vast area of space that is unusually cold in the microwave spectrum
Coldspot, a former Sears brand of refrigerators and other cooling units
Ice volcano, or more specifically a type of ice volcano that is analogous to a geological hotspot.Cryovolcano
A cryovolcano (sometimes informally called an ice volcano) is a type of volcano that erupts volatiles such as water, ammonia or methane, instead of molten rock. Collectively referred to as cryomagma, cryolava or ice-volcanic melt, these substances are usually liquids and can form plumes, but can also be in vapour form. After eruption, cryomagma is expected to condense to a solid form when exposed to the very low surrounding temperature. Cryovolcanoes may potentially form on icy moons and other objects with abundant water past the Solar System's snow line (such as Pluto). A number of features have been identified as possible cryovolcanoes on Pluto, Titan and Ceres. In addition, although they are not known to form volcanoes, ice geysers have been observed on Enceladus and potentially Triton.
One potential energy source on some solar system bodies for melting ices and producing cryovolcanoes is tidal friction. Translucent deposits of frozen materials create a subsurface greenhouse effect that would accumulate the required heat.
Signs of past warming of the Kuiper belt object Quaoar have led scientists to speculate that it exhibited cryovolcanism in the past. Radioactive decay could provide the energy necessary for such activity, as cryovolcanoes can emit water mixed with ammonia, which would melt at 180 K (−95 °C) and create an extremely cold liquid that would flow out of the volcano.Extraterrestrial liquid water
Extraterrestrial liquid water (from the Latin words: extra ["outside of, beyond"] and terrestris ["of or belonging to Earth"]) is water in its liquid state that naturally occurs outside Earth. It is a subject of wide interest because it is recognized as one of the key prerequisites for life as we know it and thus surmised as essential for extraterrestrial life.With oceanic water covering 71% of its surface, Earth is the only planet known to have stable bodies of liquid water on its surface, and liquid water is essential to all known life forms on Earth. The presence of water on the surface of Earth is a product of its atmospheric pressure and a stable orbit in the Sun's circumstellar habitable zone, though the origin of Earth's water remains unknown.
The main methods currently used for confirmation are absorption spectroscopy and geochemistry. These techniques have proven effective for atmospheric water vapour and ice. However, using current methods of astronomical spectroscopy it is substantially more difficult to detect liquid water on terrestrial planets, especially in the case of subsurface water. Due to this, astronomers, astrobiologists and planetary scientists use habitable zone, gravitational and tidal theory, models of planetary differentiation and radiometry to determine potential for liquid water. Water observed in volcanic activity can provide more compelling indirect evidence, as can fluvial features and the presence of antifreeze agents, such as salts or ammonia.
Using such methods, many scientists infer that liquid water once covered large areas of Mars and Venus. Water is thought to exist as liquid beneath the surface of some planetary bodies, similar to groundwater on Earth. Water vapour is sometimes considered conclusive evidence for the presence of liquid water, although atmospheric water vapour may be found to exist in many places where liquid water does not. Similar indirect evidence, however, supports the existence of liquids below the surface of several moons and dwarf planets elsewhere in the Solar System. Some are speculated to be large extraterrestrial "oceans". Liquid water is thought to be common in other planetary systems, despite the lack of conclusive evidence, and there is a growing list of extrasolar candidates for liquid water.Geology of Ceres
The geology of Ceres consists of the characteristics of the surface, the crust and the interior of the dwarf planet Ceres. The surface of Ceres is comparable to the surfaces of Saturn's moon Rhea and Tethys, and Uranus's moon Umbriel and Oberon.
The spectrum of Ceres is similar to that of C-type asteroids. However, since it also has spectral features of carbonates and clay minerals, which are usually absent in the spectra of other C-type asteroids, Ceres is sometimes classified as a G-type asteroid.
Ceres's surface has an albedo of 0.09, which is quite dark compared to the moons in the outer Solar System. This might be a result of the relatively high temperature of Ceres's surface, the maximum temperature with the Sun overhead was estimated from measurements to be 235 K (−38 °C; −37 °F) on 5 May 1991. In a vacuum, ice is unstable at this temperature. Material left behind by the sublimation of surface ice could explain the dark surface of Ceres compared to the icy moons of the outer Solar System.Geyser
A geyser (, UK: ) is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by steam. As a fairly rare phenomenon, the formation of geysers is due to particular hydrogeological conditions that exist only in a few places on Earth. Generally all geyser field sites are located near active volcanic areas, and the geyser effect is due to the proximity of magma. Generally, surface water works its way down to an average depth of around 2,000 metres (6,600 ft) where it contacts hot rocks. The resultant boiling of the pressurized water results in the geyser effect of hot water and steam spraying out of the geyser's surface vent (a hydrothermal explosion).
A geyser's eruptive activity may change or cease due to ongoing mineral deposition within the geyser plumbing, exchange of functions with nearby hot springs, earthquake influences, and human intervention. Like many other natural phenomena, geysers are not unique to planet Earth. Jet-like eruptions, often referred to as cryogeysers, have been observed on several of the moons of the outer solar system. Due to the low ambient pressures, these eruptions consist of vapor without liquid; they are made more easily visible by particles of dust and ice carried aloft by the gas. Water vapor jets have been observed near the south pole of Saturn's moon Enceladus, while nitrogen eruptions have been observed on Neptune's moon Triton. There are also signs of carbon dioxide eruptions from the southern polar ice cap of Mars. In the latter two cases, instead of being driven by geothermal energy, the eruptions seem to rely on solar heating via a solid-state greenhouse effect.List of Team Galaxy episodes
The following is a list of episodes from the television series, Team Galaxy.Macula (planetary geology)
Macula (pl. maculae) is the Latin word for 'spot'. It is used in planetary nomenclature to refer to unusually dark areas on the surface of a planet or moon. They are seen on the icy surfaces of Pluto, Jupiter's moon Europa, Saturn's moon Titan, Neptune's moon Triton, and Pluto's moon Charon. The term was adopted for planetary nomenclature when high resolution pictures of Europa revealed unusual new surface features.Mud volcano
The geothermal phenomena known as "mud volcanoes" are often not true mud volcanoes (pelovolcano). See mudpot for further information.A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases. Several geological processes may cause the formation of mud volcanoes. Mud volcanoes are not true igneous volcanoes as they do not produce lava and are not necessarily driven by magmatic activity. The Earth continuously exudes a mud-like substance, which may sometimes be referred to as a "mud volcano". Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide. Smaller mud exudations are sometimes referred to as mud-pots.
The mud produced by mud volcanoes is mostly formed as hot water, which has been heated deep below the Earth's surface, begins to mix and blend with subterranean mineral deposits, thus creating the mud slurry exudate. This material is then forced upwards through a geological fault or fissure due to local subterranean pressure imbalances. Mud volcanoes are associated with subduction zones and about 1100 have been identified on or near land. The temperature of any given active mud volcano generally remains fairly steady and is much lower than the typical temperatures found in igneous volcanoes. Mud volcano temperatures can range from near 100 °C (212 °F) to occasionally 2 °C (36 °F), some being used as popular "mud baths."
About 86% of the gas released from these structures is methane, with much less carbon dioxide and nitrogen emitted. Ejected materials are most often a slurry of fine solids suspended in water that may contain a mixture of salts, acids and various hydrocarbons.
Possible mud volcanoes have been identified on Mars.Outline of oceanography
The following outline is provided as an overview of and introduction to Oceanography.Palomo
Palomo ("dove"; after the shape of its glaciers) is a 4,860 metres (15,940 ft) high Chilean stratovolcano located in the commune of Machali, Cachapoal province, Libertador General Bernardo O'Higgins Region, west of Caldera del Atuel. Together with Tinguiririca it is one of two volcanoes in the region with evidence of Holocene volcanism. The volcano is remote and knowledge on its geology and potential volcanic hazards is limited.The edifice of the volcano is irregular and various estimates of its volume exist, ranging 16.6–35.5 cubic kilometres (4.0–8.5 cu mi). The best estimate is considered to be 9.2 cubic kilometres (2.2 cu mi). Palomo rises from an elevation of about 3,215 metres (10,548 ft), and it covers a surface area of 22.4 square kilometres (8.6 sq mi). Beneath the volcano lie two calderas with diameters of 3 kilometres (1.9 mi) and 5 kilometres (3.1 mi); the summit has a double crater as well, which may reflect a northeastward migration of volcanic activity. 4.5 kilometres (2.8 mi) northeast of Palomo lies the 3,300 metres (10,800 ft) high Andrès subsidiary vent. This vent features a 500 metres (1,600 ft) wide crater that opens to the south. Andrés is constructed on a granitoid basement that slopes into the valley of Rio Cortaderal, and its name relates to the son of Reynaldo Charrier, a geologist who described the subsidiary centre in 2010 and who hoped that his son would one day also know the mountain range.The volcano is flanked by glaciers.
Several of these sizeable glaciers form the Rio Blanco, Rio Cortaderal and Rio de los Cipreses on the northern flank, which drain into the Cachapoal River. A thermal event in the volcano in 1847 caused a meltwater flood on the Cachapoal River. The southern slope features the 10 kilometres (6.2 mi) Universidad Glacier, which forms the Rio San Andrés which drains into the Tinguiririrca River. With a snowline altitude of 3,100–3,300 metres (10,200–10,800 ft), it was the second longest glacier in Central Chile in 1958, but since then glaciers in the region have shrunk.The edifice is mainly constructed by lava flows that bury parts of the calderas in the foot of the volcano. Palomo has erupted andesite and dacite, as well as basaltic andesite. All rocks are calc-alkaline rocks of medium potassium content. The main edifice rocks contain abundant phenocrysts dominated by plagioclase; clinopyroxene, orthopyroxene and other minerals are less prevalent. The Andrés edifice has a distinct composition, with more amphibole and olivine and less plagioclase than the main edifice.Argon–argon dating has been used to date the rocks erupted by Palomo. The main summit yielded dates of 100,000 ± 40,000 years ago, while postglacial lavas of Andrés are dated at 40,000 ± 30,000 years ago, but volcanic activity at Palomo may have continued into pre-Hispanic times. Future activity at Palomo might generate lahars through the melting of ice, which could affect the valleys of the rivers draining the volcano.Pressure ridge (ice)
A pressure ridge develops in an ice cover as a result of a stress regime established within the plane of the ice. Within sea ice expanses, pressure ridges originate from the interaction between floes, as they collide with each other. Currents and winds are the main driving forces, but the latter are particularly effective when they have a predominant direction. Pressure ridges are made up of angular ice blocks of various sizes that pile up on the floes. The part of the ridge that is above the water surface is known as the sail; that below it as the keel. Pressure ridges are the thickest sea ice features and account for about one-half of the total sea ice volume. Stamukhi are pressure ridges that are grounded and that result from the interaction between fast ice and the drifting pack ice.Sea ice
Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs.Sotra Patera
Sotra Patera (named after the Sotra islands in Norway) is a prominent depression on Titan, the largest moon of Saturn. It was formerly known as Sotra Facula; the current name was approved on 19 December 2012. It is a possible cryovolcanic caldera 30 km (19 mi) across and 1.7 km (1.1 mi) deep, and is immediately to the east of the largest putative cryovolcanic mountain on Titan, the 1.45 km (0.90 mi) high Doom Mons. Sotra Patera is the deepest known pit on Titan.The ice volcano or cryovolcano Doom Mons forms a roughly circular mountain measuring about 65 kilometres (40 mi) across. It has two peaks standing about 1,000 metres (3,300 ft) and 1,450 metres (4,760 ft) high with multiple craters, with Sotra Patera at 1,700 metres (5,600 ft) being the deepest. Finger-like flows are visible on the flanks of the mountain, measuring perhaps 100 metres (330 ft) thick.
The Cassini–Huygens mission has mapped Sotra Patera using the Cassini orbiter's onboard radar instrument and the visual and infrared mapping spectrometer. An earlier survey of the region in 2004 revealed a circular bright spot, or facula, which was nicknamed "The Rose". A subsequent flyby by Cassini re-surveyed the region from a different angle, enabling members of the US Geological Survey Astrogeology Science Center to generate stereoscopic mapping of Sotra Patera and the surrounding area. Researchers also discovered at least two more mountains and another big crater, forming a chain of mountains several hundred kilometers long flanked by lava-covered lowlands.With Doom Mons, Sotra Patera is regarded as "the very best evidence, by far, for volcanic topography anywhere documented on an icy satellite", according to planetary scientist Jeffrey Kargel of the University of Arizona. It has been compared with terrestrial volcanoes such as Etna, Laki and volcanic cones near Flagstaff, Arizona. There is as yet no evidence of current activity, but researchers plan to monitor the area for changes.It is unclear what might have been erupted from Sotra Patera—possibly water mixed with ammonium, or more exotic hydrocarbon compounds such as polyethylene, paraffin waxes or asphalt. The eruptions may also have brought methane to the surface. Titan's dense methane atmosphere is constantly being broken down by sunlight in the upper atmosphere through photolysis; cryovolcanism may therefore explain how the atmosphere is being replenished.The eruptions of Sotra Patera are presumed to originate in a layer of liquid water lying below Titan's icy crust. The mountain's heavily cratered appearance indicates that it must have erupted with considerable force, but the precise mechanism by which this happened is not certain. Liquid water is ordinarily denser than ice but it is possible that the water's density may be reduced by mixing with other substances, such as ammonia, allowing it to force its way to the surface. Alternatively, some other mechanism such as the underground formation of methane bubbles or a build-up of tectonic pressure may be responsible.Subglacial eruption
Subglacial eruptions, those of ice-covered volcanoes, result in the interaction of magma with ice and snow, leading to meltwater formation, jökulhlaups, and lahars. Flooding associated with meltwater is a significant hazard in some volcanic areas, including Iceland, Alaska, and parts of the Andes. Jökulhlaups, glacial outburst floods, have been identified as the most frequently occurring volcanic hazard in Iceland, with major events where peak discharges can reach 10 000 – 100 000 m3/s occurring when there are large eruptions beneath glaciers.
It is important to explore volcano-ice interactions to improve our ability to effectively monitor these events and to undertake hazard assessments. This is particularly relevant given that subglacial eruptions have recently demonstrated their ability to cause widespread impact, with the ash cloud associated with Iceland's Eyjafjallajökull eruption resulting in significant impacts to aviation across Europe.Titan (moon)
Titan is the largest moon of Saturn and the second-largest natural satellite in the Solar System. It is the only moon known to have a dense atmosphere, and the only known body in space, other than Earth, where clear evidence of stable bodies of surface liquid has been found.
Titan is the sixth gravitationally rounded moon from Saturn. Frequently described as a planet-like moon, Titan is 50% larger than Earth's moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than the planet Mercury, but only 40% as massive. Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan was the first known moon of Saturn, and the sixth known planetary satellite (after Earth's moon and the four Galilean moons of Jupiter). Titan orbits Saturn at 20 Saturn radii. From Titan's surface, Saturn subtends an arc of 5.09 degrees and would appear 11.4 times larger in the sky than the Moon from Earth.
Titan is primarily composed of ice and rocky material, which is likely differentiated into a rocky core surrounded by various layers of ice, including a crust of ice Ih and a subsurface layer of ammonia-rich liquid water. Much as with Venus before the Space Age, the dense opaque atmosphere prevented understanding of Titan's surface until the Cassini–Huygens mission in 2004 provided new information, including the discovery of liquid hydrocarbon lakes in Titan's polar regions. The geologically young surface is generally smooth, with few impact craters, although mountains and several possible cryovolcanoes have been found.
The atmosphere of Titan is largely nitrogen; minor components lead to the formation of methane and ethane clouds and nitrogen-rich organic smog. The climate—including wind and rain—creates surface features similar to those of Earth, such as dunes, rivers, lakes, seas (probably of liquid methane and ethane), and deltas, and is dominated by seasonal weather patterns as on Earth. With its liquids (both surface and subsurface) and robust nitrogen atmosphere, Titan's methane cycle is analogous to Earth's water cycle, at the much lower temperature of about 94 K (−179.2 °C; −290.5 °F).Ymir (Marvel Comics)
Ymir is a fictional character appearing in American comic books published by Marvel Comics. He is based on the frost giant of the same name from Norse mythology.