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Cryovolcanism
A cryovolcano (sometimes informally referred to as an ice volcano) is a type of volcano that erupts gases and volatile material such as liquid water, ammonia, and hydrocarbons. The erupted material is collectively referred to as ''cryolava''; it originates from a reservoir of subsurface ''cryomagma''. Cryovolcanic eruptions can take many forms, such as fissure and curtain eruptions, effusive cryolava flows, and large-scale resurfacing, and can vary greatly in output volumes. Immediately after an eruption, cryolava quickly freezes, constructing geological features and altering the surface. Although rare in the inner Solar System, past and recent cryovolcanism is common on planetary objects in the outer Solar System, especially on the icy moons of the giant planets and potentially amongst the dwarf planets as well. As such, cryovolcanism is important to the geological histories of these worlds, constructing landforms or even resurfacing entire regions. Despite this, only a few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanism
Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a heat source, usually internally generated, inside the body; the heat is generated by various processes, such as radioactive decay or tidal heating. This heat partially melts solid material in the body or turns material into gas. The mobilized material rises through the body's interior and may break through the solid surface. Causes For volcanism to occur, the temperature of the mantle must have risen to about half its melting point. At this point, the mantle's viscosity will have dropped to about 1021 Pascal-seconds. When large scale melting occurs, the viscosity rapidly falls to 103 Pascal-seconds or even less, increasing the heat transport rate a million-fold. The occurrence of volcanism is partially due to the fact that melted materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is commonly defined as a vent or fissure 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 are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions."Mid-ocean ridge tectonics, volcanism and geomorphology." Geology 26, no. 455 (2001): 458. https://macdonald.faculty.geol.ucsb.edu/papers/Macdonald%20Mid-Ocean%20Ridge%20Tectonics.pdf Volcanoes can also form where there is str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Heating
Internal heat is the heat source from the interior of celestial objects, such as stars, brown dwarfs, planets, moons, dwarf planets, and (in the early history of the Solar System) even asteroids such as Vesta, resulting from contraction caused by gravity (the Kelvin–Helmholtz mechanism), nuclear fusion, tidal heating, core solidification (heat of fusion released as molten core material solidifies), and radioactive decay. The amount of internal heating depends on mass; the more massive the object, the more internal heat it has; also, for a given density, the more massive the object, the greater the ratio of mass to surface area, and thus the greater the retention of internal heat. The internal heating keeps celestial objects warm and active. Planets Terrestrial planets In the early history of the Solar System, radioactive isotopes having a half-life on the order of a few million years (such as aluminium-26 and iron-60) were sufficiently abundant to produce enough heat to cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Flow
A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of but is capable of reaching speeds up to . The gases and tephra can reach temperatures of about . Pyroclastic flows are the deadliest of all volcanic hazards and are produced as a result of certain explosive eruptions; they normally touch the ground and hurtle downhill or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope. Origin of term The word ''pyroclast'' is derived from the Greek (''pýr''), meaning "fire", and (''klastós''), meaning "broken in pieces". A name for pyroclastic flows that glow red in the dark is (French, "burning cloud"); this was notably used to describe the disastrous 1902 eruption of Mount Pelée on Martinique, a Frenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fracture in the Crust (geology), crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is often also called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. Etymology The word ''lava'' comes from Ital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and volcanic gas, gas bubbles. Magma is produced by melting of the mantle (geology), mantle or the Crust (geology), crust in various tectonics, tectonic settings, which on Earth include subduction zones, continental rift (geology), rift zones, mid-ocean ridges and Hotspot (geology), hotspots. Mantle and crustal melts migrate upwards through the crust where they are thought to be stored in magma chambers or trans-crustal crystal mush, crystal-rich mush zones. During magma's storage in the crust, its composition may be modified by Fractional crystallization (geology), fractional crystallization, contaminati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Channel
A lava channel is a stream of fluid lava contained within zones of static (i.e., solid and stationary) lava or lava levees. The initial channel may not contain levees per se, until the parental flow solidifies over what develops into the channel and creates natural levees. This initial levee allows for the building of a more complex levee and channel. As the lava flows through the channel, the elevation of the surface of the lava flow pulsates and lava can possibly flood the associated channel walls spilling out of the channel and over the existing levees, creating what is known as overflow levees. Overflow levees increase the height and width of the original levee. The lava that flows in lava channels is commonly basaltic in composition. In fiction Lava channels are found throughout the 2002 video game '' The Elder Scrolls III: Morrowind'' under the Elvish name ''Foyadas'', which features them as important routes on the volcanic island of Vvardenfell used by the native Ashlanders ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer to all explosive eruption products (correctly referred to as '' tephra''), including particles larger than 2 mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere. The force of the gases shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash is also produced when magma comes into contact with water during phreatomagmatic eruptions, causing the water to explosively flash to steam leading to shattering of magma. Once in the air, ash is transported by wind up to thousands of kilometres away. Due to its wide dispersal, ash can have a number of impacts on society, including animal a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leviathan Patera Volcanic Dome
Leviathan ( ; ; ) is a sea serpent demon noted in theology and mythology. It is referenced in several books of the Hebrew Bible, including Psalms The Book of Psalms ( , ; ; ; ; , in Islam also called Zabur, ), also known as the Psalter, is the first book of the third section of the Tanakh (Hebrew Bible) called ('Writings'), and a book of the Old Testament. The book is an anthology of B ..., the Book of Job, the Book of Isaiah, and the Pseudepigrapha, pseudepigraphical Book of Enoch. Leviathan is often an embodiment of chaos, threatening to eat the damned when their lives are over. In the end, it is annihilated. Christian theologians identified Leviathan with the demon of the seven deadly sins, deadly sin ''envy''. According to Ophite Diagrams, Ophite diagrams, Leviathan encapsulates the space of the material world. In Gnosis, it encompasses the world like a sphere and incorporates the souls of those who are too attached to material things, so they cannot reach the Plero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek Dark Ages, Dark Ages (), the Archaic Greece, Archaic or Homeric Greek, Homeric period (), and the Classical Greece, Classical period (). Ancient Greek was the language of Homer and of fifth-century Athens, fifth-century Athenian historians, playwrights, and Ancient Greek philosophy, philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Homeric Greek, Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cinder Cone
A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around the vent to form a cone that is often symmetrical, with slopes between 30° and 40° and a nearly circular base. Most cinder cones have a bowl-shaped volcanic crater, crater at the summit. Mechanics of eruption Cinder cones range in size from tens to hundreds of meters tall. They are composed of loose pyroclastic material (Scoria, cinder or scoria), which distinguishes them from ''spatter cones'', which are composed of agglomerated volcanic bombs. The pyroclastic material making up a cinder cone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spatter Cone
Volcanic cones are among the simplest volcano, volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone (geometry), cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include #Stratocone, stratocones, #Spatter cone, spatter cones, #Tuff cones, tuff cones, and cinder cones. Stratocone Stratocones are large cone-shaped volcanoes made up of lava flows, explosively erupted Pyroclastic rock, pyroclastic rocks, and igneous intrusives that are typically centered around a cylindrical vent. Unlike shield volcanoes, they are characterized by a steep profile and periodic, often alternating, explosive eruptions and effusive eruptions. Some have collapsed craters called calderas. The central core of a stratocone is commonly dominated by a central core of intrusive rocks that range from around to over several kilome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
