Dull, black stony meteorite, with little or no metal and abundant carbon; iron occurs as sulphide, silicate, or oxide. Carbonaceous chondrites show very little metamorphism but display evidence of chemical alteration by water, which continued after their formation, suggesting the parent body was rocky material mixed with ice. They contain a varied suite of organic compounds, including amino acids and a high content of inert gases. Carbonaceous chondrites have very primitive compositions, comparable to that of the Sun's atmosphere and the nebula from which the solar system formed. See also meteorite. Compare achondrite.
Subjects: Astronomy and Astrophysics — Earth Sciences and Geography.