What is a CV chondrite?
A CV chondrite is a carbonaceous chondrite with large chondrules and abundant CAIs, such as Allende, the source of many key discoveries about the early Solar System.
CV chondrites are a group of carbonaceous chondrites named after the Vigarano meteorite, which fell in Italy in 1910.
What they look like. CV chondrites are dark grey with large chondrules, often a millimetre or more across, and many white or pinkish calcium-aluminium-rich inclusions, or CAIs, some centimetres across. They also contain amoeboid olivine aggregates and a fine matrix of iron-rich olivine.
Subgroups. CVs are divided into subgroups based on their alteration. Reduced CVs, such as Vigarano and Efremovka, contain metal and are less altered. Oxidised CVs, such as Allende and Bali, contain magnetite and secondary minerals produced by fluids and heating on the parent body.
Scientific importance. CVs are especially important because of their large CAIs. Allende, which fell in Mexico in 1969, delivered more than 2 tonnes, providing abundant material for research. CAIs from Allende and other CVs have been dated to about 4,567 million years ago, defining the age of the Solar System. CVs also revealed evidence of short-lived radioactive aluminium-26 and variations in oxygen isotopes that launched a major field of research.
Magnetism. Studies of Allende magnetism suggest its parent body may have had a partly molten interior with a core dynamo, while its outer layers remained chondritic.
Parent body. CV chondrites have been linked to K-type asteroids, such as members of the Eos family, though this is uncertain.
Petrologic type. Most CVs are type 3, meaning they were heated only moderately.