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Angra Dos Reis Meteorite
The Angra dos Reis meteorite is the type specimen of the angrite group. It was observed when it fell to earth in 1869. Discovery and naming The meteorite is named after Angra dos Reis, a municipality of Rio de Janeiro, Brazil. It fell on 20 January 1869 into the bay where the water was about 2 meters deep. Two fragments were found by a diver the next day. Museum The National Museum of Brazil holds the meteorite as part of its meteorite collection. After the museum's 2018 fire, there were concerns that it was lost in the rubble of the museum. Some meteorites were found on October 19, 2018, including the ''Angra dos Reis''. Mineralogy Although it is the type specimen of the angrites, Angra dos Reis is actually very different from most other angrites. It consists almost entirely of a rare form of pyroxene called fassaite. This makes it more like a pyroxenite than the typical angrite, which is similar to a basalt. The only other meteorite samples that contain fassaite are the ca ... [...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 meteorit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fassaite
Fassaite is a variety of augite with a very low iron content, . It is named after the Fassa Valley, Italy. It is thought to be a contact mineral formed at high temperature on the interface between volcanic rocks and limestone. It is also reported in meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object en ...s. References * Inosilicates Monoclinic minerals Minerals in space group 15 {{Silicate-mineral-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1869 In Brazil
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Events in the year 1869 in Brazil. Incumbents *Monarch: Pedro II *Prime Minister: Viscount of Itaboraí Events Births Deaths References 1860s in Brazil Years of the 19th century in Brazil Brazil Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown m ... [...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 sto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redox
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allende Meteorite
The Allende meteorite is the largest carbonaceous chondrite ever found on Earth. The fireball was witnessed at 01:05 on February 8, 1969, falling over the Mexican state of Chihuahua. After it broke up in the atmosphere, an extensive search for pieces was conducted and over 2 tonnes (2.2 tons) were recovered. The availability of large quantities of samples of the scientifically-important chondrite class has enabled numerous investigations by many scientists; it is often described as "the best-studied meteorite in history." The Allende meteorite has abundant, large calcium–aluminium-rich inclusions (CAI), which are among the oldest objects formed in the Solar System. Carbonaceous chondrites compose about 4 percent of all meteorites observed to fall from space. Prior to 1969, the carbonaceous chondrite class was known from a small number of uncommon meteorites such as Orgueil, which fell in France in 1864. Meteorites similar to Allende were known, but many were small and poorly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalt
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick sequence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroxenite
Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite. Pyroxenites are classified into clinopyroxenites, orthopyroxenites, and the websterites which contain both types of pyroxenes (see diagram below). Closely allied to this group are the hornblendites, consisting essentially of hornblende and other amphiboles. They are essentially of igneous origin, though some pyroxenites are included in the metamorphic Lewisian complex of Scotland. The pyroxene-rich rocks, which result from the type of contact metamorphism known as pyroxene-hornfels facies, have siliceous sediment or basaltic protoliths, and are respectively metapelites and metabasites. Intrusive and mantle pyroxenites Igneous pyroxenites are closely allied to gabbros and norites, from which they differ by the absence of feldspar, and to peridotites, which are distinguished from them by containing more than 40% olivine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) or magnesium (Mg) and more rarely zinc, manganese or lithium, and Y represents ions of smaller size, such as chromium (Cr), aluminium (Al), magnesium (Mg), cobalt (Co), manganese (Mn), scandium (Sc), titanium (Ti), vanadium (V) or even iron (Fe II) or (Fe III). Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that crystallize in the orthorhombic system are known as orthopyroxenes. The name ''pyroxene'' is derived from the Ancient Greek words for 'fire' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angrite
Angrites are a rare group of achondrites consisting mostly of Al-Ti bearing diopside, hedenbergite, olivine, anorthite and troilite with minor traces of phosphate and metals. The group is named for the Angra dos Reis meteorite. They are the oldest igneous rocks, with crystallization ages of around 4.56 billion years. Angrites are subdivided into two main groups, the quenched and plutonic angrites. The quenched angrites cooled rapidly upon the surface of the angrite parent body (APB), whereas the plutonic angrites cooled slower, deeper in the crust. The APB is thought to have been a similar size to the asteroid 4 Vesta. Origin Angrite meteorites are distinct from other meteoritic groups based on their oxygen isotopic compositions. Based on their Mn-Fe ratios in pyroxene and other isotopic compositions, the source of angrites is constrained to the inner Solar System. However, recent studies have suggested that the APB experienced mixing of multiple sources during its histor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
