Carbonaceous chondrite

Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 7 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. C chondrites represent only a small proportion (4.6%) of meteorite falls.

Some famous carbonaceous chondrites are: Allende, Murchison, Orgueil, Ivuna, Murray, and Tagish Lake.

Composition and classification

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 percentages (3% to 22%) of water, as well as organic compounds. They are composed mainly of silicates, oxides and sulfides, while the minerals olivine and serpentinite 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 from which the solar system 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.

CI group

This group, named after the......
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