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Peraluminous
Peraluminous rocks are igneous rocks that have a molecular proportion of aluminium oxide higher than the combination of sodium oxide, potassium oxide and calcium oxide.Blatt, Harvey and Robert J. Tracy, ''Petrology,'' Freeman, 2nd ed., 1995, p. 516 This contrasts with peralkaline in which the alkalis are higher, metaluminous where aluminium oxide concentration is lower than the combination, but above the alkalis, and subaluminous in which aluminia concentration is lower than the combination. Examples of peraluminous minerals include biotite, muscovite, cordierite, andalusite and garnet. Peraluminous corresponds to the aluminum saturation index values greater than 1. Peraluminous magmas can form S-type granitoids and have been linked to collisional orogenies and to the formation of tin, tungsten and silver deposits such as those in the Bolivian tin belt The Bolivian tin belt ( es, Cinturón estanifero boliviano, provincia estannifera boliviana) is a mineral-rich region in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peraluminous
Peraluminous rocks are igneous rocks that have a molecular proportion of aluminium oxide higher than the combination of sodium oxide, potassium oxide and calcium oxide.Blatt, Harvey and Robert J. Tracy, ''Petrology,'' Freeman, 2nd ed., 1995, p. 516 This contrasts with peralkaline in which the alkalis are higher, metaluminous where aluminium oxide concentration is lower than the combination, but above the alkalis, and subaluminous in which aluminia concentration is lower than the combination. Examples of peraluminous minerals include biotite, muscovite, cordierite, andalusite and garnet. Peraluminous corresponds to the aluminum saturation index values greater than 1. Peraluminous magmas can form S-type granitoids and have been linked to collisional orogenies and to the formation of tin, tungsten and silver deposits such as those in the Bolivian tin belt The Bolivian tin belt ( es, Cinturón estanifero boliviano, provincia estannifera boliviana) is a mineral-rich region in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaluminous
Metaluminous rocks are igneous rocks that have a molar proportion of aluminium oxide lower than the combination of calcium oxide, sodium oxide and potassium oxide. This contrasts with peraluminous rocks in which the aluminium oxide concentration is higher than the combination, and peralkaline rocks where the alkalis are higher. Most mafic rocks are metaluminous, having neither excess aluminium nor alkalis. In such rocks the alkalis are mostly accommodated in feldspars, and the remaining calcium and minor sodium are found in hornblende and augite Augite is a common rock-forming pyroxene mineral with formula . The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees. Characteristics Augite is a solid solution in the pyroxene group. .... References Igneous rocks {{petrology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscovite
Muscovite (also known as common mica, isinglass, or potash mica) is a hydrated phyllosilicate mineral of aluminium and potassium with formula K Al2(Al Si3 O10)( F,O H)2, or ( KF)2( Al2O3)3( SiO2)6( H2O). It has a highly perfect basal cleavage yielding remarkably thin laminae (sheets) which are often highly elastic. Sheets of muscovite 5 meters × 3 meters (16.5 feet × 10 feet) have been found in Nellore, India. Muscovite has a Mohs hardness of 2–2.25 parallel to the 01face, 4 perpendicular to the 01and a specific gravity of 2.76–3. It can be colorless or tinted through grays, browns, greens, yellows, or (rarely) violet or red, and can be transparent or translucent. It is anisotropic and has high birefringence. Its crystal system is monoclinic. The green, chromium-rich variety is called fuchsite; mariposite is also a chromium-rich type of muscovite. Muscovite is the most common mica, found in granites, pegmatites, gneisses, and schists, and as a contact metamorphic ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolivian Tin Belt
The Bolivian tin belt ( es, Cinturón estanifero boliviano, provincia estannifera boliviana) is a mineral-rich region in the Cordillera Oriental of Bolivia. Being a metallogenetic province the Bolivian tin belt is rich in tin, tungsten, silver and base metals. The Bolivian tin belt follows the same bend as the Bolivian orocline. The mineralizations of the belt were formed episodically beginning in the Triassic and with the youngest known mineralizations dating to the Miocene. The mineral enrichment is a result of fluids expelled from peraluminous magmas. Peraluminous magmas in turn results from the partial melting (anatexis) of metasedimentary rock and gneiss in the continental crust. Analysis of trace elements in the igneous rocks formed by this magma suggests that some of its material derives from melting of a pelitic rock of Lower Paleozoic age. Besides crustal components magmas did also involve sources in the mantle. The formation of these magmas is thus a form of crusta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Oxide
Potassium oxide ( K O) is an ionic compound of potassium and oxygen. It is a base. This pale yellow solid is the simplest oxide of potassium. It is a highly reactive compound that is rarely encountered. Some industrial materials, such as fertilizers and cements, are assayed assuming the percent composition that would be equivalent to K2O. Production Potassium oxide is produced from the reaction of oxygen and potassium; this reaction affords potassium peroxide, K2O2. Treatment of the peroxide with potassium produces the oxide: : K2O2 + 2 K -> 2 K2O Alternatively and more conveniently, K2O is synthesized by heating potassium nitrate with metallic potassium: :2KNO3 + 10K -> 6K2O + N2 (^) Other possibility is to heat potassium peroxide at 500 °C which decomposes at that temperature giving pure potassium oxide and oxygen. :2K2O2 -> 2K2O + O2 (^) Potassium hydroxide cannot be further dehydrated to the oxide but it can react with molten potassium to produce it, releasing hydr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Oxide
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, Caustic (substance), caustic, alkaline, crystalline solid at room temperature. The broadly used term "''lime (material), lime''" connotes calcium-containing inorganic materials, in which carbonates, oxides and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate. By contrast, ''quicklime'' specifically applies to the single chemical compound calcium oxide. Calcium oxide that survives processing without reacting in building products such as cement is called free lime. Quicklime is relatively inexpensive. Both it and a chemical derivative (calcium hydroxide, of which quicklime is the base anhydride) are important commodity chemicals. Preparation Calcium oxide is usually made by the thermal decomposition of materials, such as limestone or seashells, that contain calcium carbonate (CaCO3; mineral calcite) in a lime kiln. This is accomplished by hea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peralkaline
Peralkaline rocks include those igneous rocks which have a deficiency of aluminium such that sodium and potassium are in excess of that needed for feldspar. The presence of aegerine (sodium pyroxene) and riebeckite (sodium amphibole) are indicative of peralkaline conditions. Examples are the peralkaline rhyolites, comendite and pantellerite, with comendite being the more felsic (silica-rich) rock. Another example is the peralkaline granite that forms the islet of Rockall in the North Atlantic Ocean. Peralkaline rocks are indicative of continental rift-related volcanicity (e.g. the peralkaline rhyolites of the East African Rift in central Kenya) as well as continental and oceanic hotspot volcanicity (e.g. the peralkaline rhyolites of the Glass House Mountains in eastern Australia and the Canary Islands in the Atlantic Ocean). Peralkaline rocks related to subduction zone volcanicity have also been reported (e.g. Sardinia in Italy). Peralkaline magmas likely form when fractional crys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Oxide
Sodium oxide is a chemical compound with the formula Na2 O. It is used in ceramics and glasses. It is a white solid but the compound is rarely encountered. Instead "sodium oxide" is used to describe components of various materials such as glasses and fertilizers which contain oxides that include sodium and other elements. Structure The structure of sodium oxide has been determined by X-ray crystallography. Most alkali metal oxides M2O (M = Li, Na, K, Rb) crystallise in the antifluorite structure. In this motif the positions of the anions and cations are reversed relative to their positions in CaF2, with sodium ions tetrahedrally coordinated to 4 oxide ions and oxide cubically coordinated to 8 sodium ions. Preparation Sodium oxide is produced by the reaction of sodium with sodium hydroxide, sodium peroxide, or sodium nitrite: : 2 NaOH + 2 Na → 2 Na2O + H2 To the extent that NaOH is contaminated with water, correspondingly greater amounts of sodium are employed. Excess s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Minerals'; p. 1. In the series ''Geology: Landforms, Minerals, and Rocks''. Rosen Publishing Group. The geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or are organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks. The concept of mineral is distinct from rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral, or may be an aggregate of two or more different types of minerals, spacially segregated into distinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous Rock
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from Partial melting, partial melts of existing rocks in either a Terrestrial planet, planet's mantle (geology), mantle or crust (geology), crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive (geology), extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form Volcanic glass, natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
