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IIICD Meteorites
IIICD meteorites are a group of primitive achondrites. They are classified in a clan together with the IAB meteorites and the winonaites. Description IIICD meteorites consists dominantly of meteoric iron with silicate inclusions. The silicate inclusions are almost identical to the IAB meteorite inclusions. They contain low-Ca pyroxene, high-Ca pyroxene, olivine, plagioclase, troilite, graphite, different phosphates, meteoric iron and traces of daubréelite and chromite. Parent body It has been established that IAB meteorites and winonaites originated from the same parent body. The same is not yet clear for IIICD meteorites, that originated from the same or a very similar asteroid. Classification The IIICD meteorites are classified as primitive achondrites because they have silicate inclusions and show signs of partial melting. The silicate inclusion are almost identical to silicate inclusions in IAB meteorites, and both are very similar to winonaites. For this reason all t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achondrite
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes. Achondrites account for about 8% of meteorites overall, and the majority (about two-thirds) of them are HED meteorites, possibly originating from the crust of asteroid 4 Vesta. Other types include Martian, Lunar, and several types thought to originate from as-yet unidentified asteroids. These groups have been determined on the basis of e.g. the Fe/ Mn chemical ratio and the 17O/18O oxygen isotope ratios, thought to be characteristic "fingerprints" for each parent body. Classification Achondrites are classified into the following groups:O. Richard Norton. The Cambridge encyclopedia of meteorites. U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plagioclase
Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more properly known as the plagioclase feldspar series. This was first shown by the German mineralogist Johann Friedrich Christian Hessel (1796–1872) in 1826. The series ranges from albite to anorthite endmembers (with respective compositions NaAlSi3O8 to CaAl2Si2O8), where sodium and calcium atoms can substitute for each other in the mineral's crystal lattice structure. Plagioclase in hand samples is often identified by its polysynthetic crystal twinning or 'record-groove' effect. Plagioclase is a major constituent mineral in the Earth's crust, and is consequently an important diagnostic tool in petrology for identifying the composition, origin and evolution of igneous rocks. Plagioclase is also a major constituent of rock in the highlan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primitive Achondrites
Primitive achondrites are a subdivision of meteorites. They are classified on the same rank (historically called "Class") and lying between chondrites and achondrites. They are called primitive because they are achondrites that have retained much of their original chondritic properties. Very characteristic are relic chondrules and chemical compositions close to the composition of chondrites. These observations are explained as melt residues, partial melting, or extensive recrystallization. History The concept of primitive achondrites was first summarized in 1983. In 2006 a classification was published that assigned 7 groups to the primitive achondrites, but the classification remains controversial. The authors define primitive achondrites as meteorites "''that exceeded their solidus temperature on the parent body''" and thus would partially melt. Meteorites that have been fully melted are included if they did not reach isotopic equilibrium on their parent body. Description There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteoric Iron
Meteoric iron, sometimes meteoritic iron, is a native metal and early-universe protoplanetary-disk remnant found in meteorites and made from the elements iron and nickel, mainly in the form of the mineral phases kamacite and taenite. Meteoric iron makes up the bulk of iron meteorites but is also found in other meteorites. Apart from minor amounts of telluric iron, meteoric iron is the only naturally occurring native metal of the element iron (in metallic form rather than in an ore) on the Earth's surface. Mineralogy The bulk of meteoric iron consists of taenite and kamacite. Taenite is a face-centered cubic and kamacite a body-centered cubic iron-nickel alloy. Meteoric iron can be distinguished from telluric iron by its microstructure and perhaps by its chemical composition also, since meteoritic iron contains more nickel and less carbon. Trace amounts of gallium and germanium in meteoric iron can be used to distinguish different meteorite types. The meteoric iron in stony iron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winonaite
Winonaites are a group of primitive achondrite meteorites. Like all primitive achondrites, winonaites share similarities with chondrites and achondrites. They show signs of metamorphism, partial melting, brecciation and relic chondrules. Their chemical and mineralogical composition lies between H and E chondrites. Naming and history The winonaite group is named after the type specimen, the Winona meteorite. The name itself derived from Winona, Arizona where the type specimen was said to be found during an archaeological excavation of the Sinagua village Elden Pueblo in September 1928. The Sinagua lived in the village between 1150 and 1275. The meteorite was said to be retrieved from the cist of one of the rooms. However, a later study indicates the meteorite was found at another Sinagua site and not in Elden Pueblo.A. L. Christenson "J. W. Simmons' account of the discovery of the Winona meteorite."''Meteorite'' 10(3):14–16, 2004. As of 2021, 54 meteorites are included in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IAB Meteorites
IAB meteorites are a group of iron meteorites according to their overall composition and a group of primitive achondrites because of silicate inclusions that show a strong affinity to winonaites and chondrites. Description The IAB meteorites are composed of meteoric iron (kamacite and taenite) and silicate inclusions. Structurally they can be hexahedrites, fine to coarse octahedrites, or even ataxites. Most of them are octahedrite with medium to coarse taenite-lamella and distinct Widmanstätten patterning. The silicate inclusions are composed of low-Ca pyroxene, high-Ca pyroxene, olivine, plagioclase, troilite, graphite, different phosphates, meteoric iron and traces of daubréelite and chromite. This composition is very similar to the composition of winonaites, and it is therefore argued that the two groups share the same parent body. There are also similarities with the IIICD meteorites, but it is not yet clear whether they are also part of that parent body. Classification T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primitive Achondrite
Primitive achondrites are a subdivision of meteorites. They are classified on the same rank (historically called "Class") and lying between chondrites and achondrites. They are called primitive because they are achondrites that have retained much of their original chondritic properties. Very characteristic are relic chondrules and chemical compositions close to the composition of chondrites. These observations are explained as melt residues, partial melting, or extensive recrystallization. History The concept of primitive achondrites was first summarized in 1983. In 2006 a classification was published that assigned 7 groups to the primitive achondrites, but the classification remains controversial. The authors define primitive achondrites as meteorites "''that exceeded their solidus temperature on the parent body''" and thus would partially melt. Meteorites that have been fully melted are included if they did not reach isotopic equilibrium on their parent body. Description There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromite
Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of FeCr2O4. It is an oxide mineral belonging to the spinel group. The element magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (MgCr2O4). A substitution of the element aluminium can also occur, leading to hercynite (FeAl2O4). Chromite today is mined particularly to make stainless steel through the production of ferrochrome (FeCr), which is an iron-chromium alloy. Chromite grains are commonly found in large mafic igneous intrusions such as the Bushveld in South Africa and India. Chromite is iron-black in color with a metallic luster, a dark brown streak and a hardness on the Mohs scale of 5.5. Properties Chromite minerals are mainly found in mafic-ultramafic igneous intrusions and are also sometimes found in metamorphic rocks. The chromite minerals occur in layered format ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daubréelite
Daubréelite is a rare sulfide mineral. It crystallizes with cubic symmetry and has chemical composition of Fe2+Cr3+2S4. It usually occurs as black platy aggregates. Naming and history Daubréelite was named after the French mineralogist, petrologist and meteoriticist Gabriel Auguste Daubrée. The mineral was first described in 1876 in the ''American Journal of Science''. Its type locality is the Coahuila meteorite, Bolsom de Mapimí, Coahuila, Mexico. Classification In the Nickel-Strunz classification daubréelite is part of the "Sulfides and Sulfosalts" and further a "metal sulfide with a metal-sulfide ratio of 3:4 and 2:3". Occurrences Daubréelite is found in iron meteorites as an inclusion in meteoric iron (kamacite and taenite). Further paragenetic minerals are alabandine, enstatite, graphite, plagioclase and schreibersite. According to one source daubréelite has been described from 34 localities. Some notable examples being the ALH 84001 meteorite, Hoba meteorite, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphate
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosphoric acid by the removal of three protons . Removal of one or two protons gives the dihydrogen phosphate ion and the hydrogen phosphate ion ion, respectively. These names are also used for salts of those anions, such as ammonium dihydrogen phosphate and trisodium phosphate. File:3-phosphoric-acid-3D-balls.png, Phosphoricacid File:2-dihydrogenphosphate-3D-balls.png, Dihydrogenphosphate File:1-hydrogenphosphate-3D-balls.png, Hydrogenphosphate File:0-phosphate-3D-balls.png, Phosphate In organic chemistry, phosphate or orthophosphate is an organophosphate, an ester of orthophosphoric acid of the form where one or more hydrogen atoms are replaced by organic groups. An example is trimethyl phosphate, . The term also refers to the triv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphite
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large scale (300 kton/year, in 1989) for uses in pencils, lubricants, and electrodes. Under high pressures and temperatures it converts to diamond. It is a weak conductor of heat and electricity. Types and varieties Natural graphite The principal types of natural graphite, each occurring in different types of ore deposits, are * Crystalline small flakes of graphite (or flake graphite) occurs as isolated, flat, plate-like particles with hexagonal edges if unbroken. When broken the edges can be irregular or angular; * Amorphous graphite: very fine flake graphite is sometimes called amorphous; * Lump graphite (or vein graphite) occurs in fissure veins or fractures and appears as massive platy intergrowths of fibrous or acicular crystalline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troilite
Troilite is a rare iron sulfide mineral with the simple formula of FeS. It is the iron-rich endmember of the pyrrhotite group. Pyrrhotite has the formula Fe(1-x)S (x = 0 to 0.2) which is iron deficient. As troilite lacks the iron deficiency which gives pyrrhotite its characteristic magnetism, troilite is non-magnetic. Troilite can be found as a native mineral on Earth but is more abundant in meteorites, in particular, those originating from the Moon and Mars. It is among the minerals found in samples of the meteorite that struck Russia in Chelyabinsk on February 15th, 2013. Uniform presence of troilite on the Moon and possibly on Mars has been confirmed by the Apollo, Viking and Phobos space probes. The relative intensities of isotopes of sulfur are rather constant in meteorites as compared to the Earth minerals, and therefore troilite from Canyon Diablo meteorite is chosen as the international sulfur isotope ratio standard, the Canyon Diablo Troilite (CDT). Structure Troilit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
