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Carbonaceous chondrite

 
Carbonaceous Chondrite

 
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Carbonaceous chondrite
 
 
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Carbonaceous chondrites or C chondrites are a class of chondritic
Chondrite

Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids....
 meteorite
Meteorite

A meteorite is a natural object originating in outer space that survives an impact with the Earth's surface. While in space it is called a meteoroid....
s comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. C chondrites represent only a small proportion (~5%) of meteorite falls.

Carbonaceous chondrites are grouped according to distinctive compositions thought to reflect the type of parent body from which they originated.






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Carbonaceous Chondrites
Carbonaceous chondrites or C chondrites are a class of chondritic
Chondrite

Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids....
 meteorite
Meteorite

A meteorite is a natural object originating in outer space that survives an impact with the Earth's surface. While in space it is called a meteoroid....
s comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. C chondrites represent only a small proportion (~5%) of meteorite falls.

Carbonaceous chondrites are grouped according to distinctive compositions thought to reflect the type of parent body from which they originated. These are named after a prominent meteorite—often the first to be discovered—in the group.

Several groups of carbonaceous chondrites, notably the CM and CI groups, contain high levels of water
Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
 and organic compound
Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
s. They are composed mainly of silicate
Silicate

A silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. This definition is broad enough to include species such as hexafluorosilicate , [SiF6]2-, but the silicate species that are encountered most often consist of silicon with oxygen as the ligand...
s, oxide
Oxide

An oxide is a chemical compound contaning at least one oxygen atom as well as at least one other element. Most of the Earth's crust consists of oxides....
s and sulfide
Sulfide

The term sulfide refers to several types of chemical compounds containing sulfur in its lowest oxidation number of −2.Formally, "sulfide" is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2...
s, while the minerals olivine
Olivine

The mineral olivine is a magnesium iron Silicate minerals with the formula 2siliconoxygen4. It is one of the most common minerals on Earth, and has also been identified in meteorites and on the Moon, Mars, and comet Wild 2....
 and serpentine
Serpentine

The serpentine group describes a group of common rock-forming hydroxy magnesium iron Silicate minerals#Phyllosilicates minerals; they may contain minor amounts of other elements including chromium, manganese, cobalt and nickel....
 are characteristic. The presence of volatile organic chemicals and water indicates that they have not undergone significant heating (>200°C) since they formed, and their compositions are considered to be close to that of the solar nebula
Solar nebula

In cosmogony, the nebular hypothesis is the most widely accepted model explaining the formation and evolution of the Solar System. It was first proposed in 1734 by Emanuel Swedenborg....
 from which the solar system
Solar System

The Solar System consists of the Sun and those Astronomical object bound to it by gravity: the eight planets and five dwarf planets, their 173 known Natural satellite, and billions of Small Solar System body....
 condensed. Other groups of C chondrites, e.g. CO, CV, and CK chondrites, are relatively poor in volatile compounds, and some of these have experienced significant heating on their parent asteroids.

Some famous carbonaceous chondrites are: Orgueil, Ivuna, Murray, Murchison
Murchison meteorite

The Murchison meteorite is named after Murchison, Victoria, in Australia. It is one of the most studied meteorites due to its large mass , the fact that it was an observed Meteorite fall, and it belongs to a group of meteorites rich in organic compounds....
, Tagish Lake and Allende
Allende meteorite

The Allende meteorite is the largest carbonaceous chondrite ever found on Earth. The Meteoroid#Fireball was witnessed at 1:05 a.m. on February 8, 1969, falling over the Mexican state of Chihuahua ....
.

CI group

This group, named after the Ivuna meteorite, have chemical compositions that are close to that measured in the solar photosphere, neglecting gaseous elements. In this sense, they are chemically the most primitive known meteorites. They typically contain a high proportion of water (up to 20%), and organic matter in the form of amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
s and PAH
Polycyclic aromatic hydrocarbon

Polycyclic aromatic hydrocarbons are chemical compounds that consist of fused aromatic simple aromatic ring and do not contain heteroatoms or carry substituents....
s. Aqueous alteration promotes a composition of hydrous phyllosilicate
Silicate minerals

The silicate minerals make up the largest and most important class of rock-forming minerals, comprising approximately 90 percent of the crust of the Earth....
s, magnetite
Magnetite

Magnetite is a ferrimagnetism mineral with chemical formula Iron3Oxygen4, one of several iron oxides and a member of the spinel group....
, and olivine
Olivine

The mineral olivine is a magnesium iron Silicate minerals with the formula 2siliconoxygen4. It is one of the most common minerals on Earth, and has also been identified in meteorites and on the Moon, Mars, and comet Wild 2....
 crystals occurring in a black matrix, and a possible lack of chondrule
Chondrule

Most meteorites that meteorite falls on Earth are chondrites, which are characterized by the presence of round grains called chondrules . Chondrules formed as molten or partially molten droplets in space before being accretion to their parent asteroids....
s. It is thought they have not been heated above , indicating that they condensed in the cooler outer portion of the solar nebula.

Five CI chondrites have been observed to fall: Ivuna, Orgueil, Alais, Tonk and Revelstoke. Several others have been found by Japanese field parties in Antarctica. In general, the extreme fragility of CI chondrites causes them to be highly susceptible to terrestrial weathering, and they do not survive on Earth's surface for long after they fall.

Organic matter

Ehrenfreund et al. (2001) found that amino acids in Ivuna and Orgueil were present at much lower concentrations than in CM chondrites (~30%), and that they had a distinct composition high in ß-alanine
Alanine

Alanine is an a-amino acid with the chemical formula CH3CHCOOH. The L-isomer is one of the 20 proteinogenic amino acids, i.e. the building blocks of proteins....
, glycine
Glycine

Glycine is the organic compound with the chemical formula NH2CH2COOH. It is the smallest of the 20 amino acids commonly found in proteins, coded by codons GGU, GGC, GGA and GGG....
, ?-ABA, and ß-ABA but low in AIB and isovaline. This implies that they had formed by a different synthetic pathway, and on a different parent body from the CM chondrites. Most of the organic
Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
 carbon
Carbon

Carbon is a chemical element with chemical symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalence?making four electrons available to form covalent bond chemical bonds....
 in CI and CM carbonaceous chondrites is an insoluble complex material. That is similar to the description for kerogen
Kerogen

Kerogen is a mixture of organic chemistry chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic chemistry solvents because of the huge molecular mass of its component compounds....
. A kerogen-like material is also in the ALH84001
ALH84001

Allan Hills 84001 is a meteorite found in Allan Hills, Antarctica on December 27, 1984 by a team of US meteorite hunters from the ANSMET project....
 Martian meteorite (an achondrite
Achondrite

An achondrite is a stony meteorite that consists of material similar to terrestrial basalts or plutonic rocks. Compared to the chondrites, they have all been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies....
).

The CM meteorite from Murchison, Victoria
Murchison, Victoria

Murchison is a small rural village located on the Goulburn River, Victoria in Victoria , Australia. Murchison is located 167 kilometres from Melbourne and is just to the west of the Goulburn Valley Highway between Shepparton, Victoria and Nagambie, Victoria....
 has over 70 extraterrestrial amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
s and other compounds including carboxylic acid
Carboxylic acid

Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the Chemical formula -COH, usually written -COOH or -CO2H....
s, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbon
Hydrocarbon

In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. With relation to chemical terminology, aromatic hydrocarbons or arenes, alkanes, alkenes and alkyne-based compounds composed entirely of carbon or hydrogen are referred to as "pure" hydrocarbons, whereas other hydrocarbons with bonded com...
s, fullerene
Fullerene

Fullerene are a family of carbon Allotropy, molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid, cylinder , or plane....
s, heterocycles, carbonyl
Carbonyl

In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double bond to an oxygen atom : C=O.The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex ; in this situation, carbon is triple-bonded to oxygen : C=O....
 compounds, alcohol
Alcohol

In chemistry, an alcohol is any organic compound in which a hydroxyl Functional group is bound to a carbon atom of an alkyl or substituted alkyl group....
s, amine
Amine

Amines are organic compounds and functional groups that contain a base nitrogen atom with a lone pair. Amines are derivative s of ammonia, wherein one or more hydrogen atoms are replaced by organic substituents such as alkyl and aryl groups....
s and amide
Amide

In chemistry, an amide is one of three kinds of compounds:* the organic chemistry functional group characterized by a carbonyl group linked to a nitrogen atom , or a compound that contains this functional group ; or...
s.

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