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Serpentinite
Serpentinite is a rock composed predominantly of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called ''serpentine'' or ''serpentine rock'', particularly in older geological texts and in wider cultural settings.California Government Code § 425.2; ''see'' Formation and mineralogy Serpentinite is formed by near to complete serpentinization of mafic to ultramafic rocks. Serpentinite can be formed wherever ultramafic rock is infiltrated by water poor in carbon dioxide. This occurs at mid-ocean ridges and in the forearc mantle of subduction zones. The final mineral composition of serpentinite is usually dominated by lizardite, chrysotile, and magnetite. Brucite and antigorite are less commonly present. Lizardite, chrysotile, and antigorite all have approximately the formula or , but differ in minor components and in form. Accessory minerals, present in smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpentinite Sur Gneiss
Serpentinite is a Rock (geology), rock composed predominantly of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called ''serpentine'' or ''serpentine rock'', particularly in older geological texts and in wider cultural settings.California Government Code § 425.2; ''see'' Formation and mineralogy Serpentinite is formed by near to complete serpentinization of mafic to ultramafic rocks. Serpentinite can be formed wherever ultramafic rock is infiltrated by water poor in carbon dioxide. This occurs at mid-ocean ridges and in the forearc mantle of subduction zones. The final mineral composition of serpentinite is usually dominated by lizardite, chrysotile, and magnetite. Brucite and antigorite are less commonly present. Lizardite, chrysotile, and antigorite all have approximately the formula or , but differ in minor components and in form. Accessory minerals, p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpentinite
Serpentinite is a rock composed predominantly of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called ''serpentine'' or ''serpentine rock'', particularly in older geological texts and in wider cultural settings.California Government Code § 425.2; ''see'' Formation and mineralogy Serpentinite is formed by near to complete serpentinization of mafic to ultramafic rocks. Serpentinite can be formed wherever ultramafic rock is infiltrated by water poor in carbon dioxide. This occurs at mid-ocean ridges and in the forearc mantle of subduction zones. The final mineral composition of serpentinite is usually dominated by lizardite, chrysotile, and magnetite. Brucite and antigorite are less commonly present. Lizardite, chrysotile, and antigorite all have approximately the formula or , but differ in minor components and in form. Accessory minerals, present in smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpentinization
Serpentinization is a hydration and Metamorphic rock, metamorphic transformation of ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramafic rock to produce serpentinite. Minerals formed by serpentinization include the Serpentine subgroup, serpentine group minerals (antigorite, lizardite, chrysotile), brucite, talc, Ni-Fe alloys, and magnetite. The mineral alteration is particularly important at the sea floor at plate tectonics, tectonic plate boundaries. Formation and petrology Serpentinization is a form of low-temperature (0 to ~600 °C) metamorphism of ferromagnesian minerals in mafic and ultramafic rocks, such as dunite, harzburgite, or lherzolite. These are rocks low in silica and composed mostly of olivine (), pyroxene (), and chromite (approximately ). Serpentinization is driven largely by Mineral hydration, hydration and oxidation of olivine and pyroxene to serpentine subgroup, serpentine group minerals (antigorite, lizardite, and chrysotile), bru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigorite
Antigorite is a lamellated, monoclinic mineral in the phylosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinites. Antigorite, and its serpentine polymorphs, play an important role in subduction zone dynamics due to their relative weakness and high weight percent of water (up to 13 weight % H2O). It is named after its type locality, the Geisspfad serpentinite, Valle Antigorio in the border region of Italy/Switzerland and is commonly used as a gemstone in jewelry and carvings. Geologic occurrences Antigorite is found in low-temperature, high-pressure (or high-deformation) environments, including both extensional and compressional tectonic regimes. Serpentines are commonly found in the ultramafic greenschist facies of subduction zones, and are visible on the Earth's surface through secondary exhumation. Serpentinites that contain antigorite are usu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpentine Group
Serpentine subgroup (part of the kaolinite-serpentine group in the category of phyllosilicates) are greenish, brownish, or spotted minerals commonly found in serpentinite. They are used as a source of magnesium and asbestos, and as decorative stone. The name comes from the greenish colour and smooth or scaly appearance from the Latin , meaning "serpent rock". Serpentine subgroup is a set of common rock-forming hydrous magnesium iron phyllosilicate () minerals, resulting from the metamorphism of the minerals that are contained in mafic to ultramafic rocks. They may contain minor amounts of other elements including chromium, manganese, cobalt or nickel. In mineralogy and gemology, serpentine may refer to any of the 20 varieties belonging to the serpentine subgroup. Owing to admixture, these varieties are not always easy to individualize, and distinctions are not usually made. There are three important mineral polymorphs of serpentine: antigorite, lizardite and chrysotile. Serpen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiolite
An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is found in the name of ophiolites, because of the superficial texture of some of them. Serpentinite especially evokes a snakeskin. The suffix ''lite'' from the Greek ''lithos'' means "stone". Some ophiolites have a green color. The origin of these rocks, present in many mountainous massifs, remained uncertain until the advent of plate tectonic theory. Their great significance relates to their occurrence within mountain belts such as the Alps and the Himalayas, where they document the existence of former ocean basins that have now been consumed by subduction. This insight was one of the founding pillars of plate tectonics, and ophiolites have always played a central role in plate tectonic theory and the interpretation of ancient mountain belts. Pse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lost City Hydrothermal Field
The Lost City Hydrothermal Field, often referred to simply as Lost City, is an area of marine alkaline hydrothermal vents located on the Atlantis Massif at the intersection between the Mid-Atlantic Ridge and the Atlantis Transform Fault, in the Atlantic Ocean. It is a long-lived site of active and inactive ultramafic-hosted serpentinization, abiotically producing many simple molecules such as methane and hydrogen which are fundamental to microbial life. As such it has generated scientific interest as a prime location for investigating the origin of life on Earth and other planets similar to it. Expedition history The Lost City was first identified on December 4, 2000, using ''DSV Alvin'' and ''ROV ArgoII'' on cruise AT03-60 of the RV Atlantis. The cruise lasted 34 days, during which photographs and vent chimney samples were taken. The discovery of the Lost City prompted the National Science Foundation to fund a second, 32-day voyage (AT07-34) to the site in 2003 in order to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetyl-CoA
Acetyl-CoA (acetyl coenzyme A) is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production. Coenzyme A (CoASH or CoA) consists of a β-mercaptoethylamine group linked to the vitamin pantothenic acid (B5) through an amide linkage and 3'-phosphorylated ADP. The acetyl group (indicated in blue in the structural diagram on the right) of acetyl-CoA is linked to the sulfhydryl substituent of the β-mercaptoethylamine group. This thioester linkage is a "high energy" bond, which is particularly reactive. Hydrolysis of the thioester bond is exergonic (−31.5 kJ/mol). CoA is acetylated to acetyl-CoA by the breakdown of carbohydrates through glycolysis and by the breakdown of fatty acids through β-oxidation. Acetyl-CoA then enters the citric acid cycle, where the acetyl group is oxidized to carbon dioxide and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gabbro
Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt. Much of the Earth's oceanic crust is made of gabbro, formed at mid-ocean ridges. Gabbro is also found as plutons associated with continental volcanism. Due to its variant nature, the term ''gabbro'' may be applied loosely to a wide range of intrusive rocks, many of which are merely "gabbroic". By rough analogy, gabbro is to basalt as granite is to rhyolite. Etymology The term "gabbro" was used in the 1760s to name a set of rock types that were found in the ophiolites of the Apennine Mountains in Italy. It was named after Gabbro, a hamlet near Rosignano Marittimo in Tuscany. Then, in 1809, the German geologist Christian Leopold von Buch used the term more restrictively in his descri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manzanita
Manzanita is a common name for many species of the genus ''Arctostaphylos''. They are evergreen shrubs or small trees present in the chaparral biome of western North America, where they occur from Southern British Columbia and Washington to Oregon, California, Utah, Arizona, New Mexico, and Texas in the United States, and throughout Mexico. Manzanitas can live in places with poor soil and little water. They are characterized by smooth orange or red bark and stiff, twisting branches. There are 105 species and subspecies of manzanita, 95 of which are found in the Mediterranean climate and colder mountainous regions of California, ranging from ground-hugging coastal and mountain species to small trees up to 20 feet (6m) tall. Manzanitas bloom in the winter to early spring and carry berries in spring and summer. The berries and flowers of most species are edible. The word ''manzanita'' is the Spanish diminutive of ''manzana'' (apple). A literal translation would be ''little apple' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
