Aubrites

Aubrites are a rare group of meteorites classified as enstatite achondrites. The name comes from the type specimen Aubres, found near Aubres in southeastern France, which established the group. These rocks are igneous in origin and are believed to originate from a differentiated parent body, such as a small asteroid, rather than from primitive, undifferentiated material.

The bulk mineralogy of aubrites is dominated by enstatite (MgSiO3) and they characteristically exhibit extremely reducing, low-oxidation-state conditions. They typically have low abundances of metal oxides and low FeO content in silicates, reflecting their unique formation environment. Textures range from fine to coarse grained and can be brecciated, with enstatite as a major constituent and only minor amounts of other minerals, such as feldspars in some specimens. Metallic phases, when present, are usually limited in scope.

Origin and classification emphasize their igneous nature: aubrites formed through melting and differentiation on a parent body, producing enstatite-rich rocks in contrast to primitive enstatite chondrites. Their highly reduced nature and distinctive mineralogy set them apart from most other meteorite groups, including other enstatite meteorites.

Notable examples include the type specimen Aubres and the Norton County meteorite, among a small number of recovered aubrites. Due to their rarity and distinctive composition, aubrites provide important insights into the diversity of planetary bodies in the early solar system and the range of igneous processes that can occur on small bodies.