The Kaidun Microbreccia Meteorite: A Harvest from the Inner and Outer Asteroid Belt
We summarize the results of two decades of research into the complex Kaidun microbrecccia meteorite. This meteorite contains an unprecedented accumulation of materials from many different asteroids, principally carbonaceous and enstatite chondrites, but also many other frequently strange materials. The following well-known meteorite types are definitely present in Kaidun: EH3–5, EL3, CV3, CM1-2, and R chondrites. Also present in Kaidun are new C1 and C2 type lithologies, unique alkaline-enriched clasts, impact melt products, phosphide-bearing clasts, vein- and cavity-filling materials, new enstatite-bearing clasts, and Ca-rich achondrite materials. Many further materials have yet to be characterized.
Obviously, the Kaidun parent object accumulated materials from across the entire main asteroid belt. Many of these materials were subjected to varying levels of physical processing, heating, shock, melting, and aqueous alteration.
Kaidun is important because it contains many asteroidal materials we have not seen before, providing a more complete view of the diversity of materials in the asteroid belt than has been provided by other meteorites. This is possible because of the small, generally sub-millimeter-size of the component clasts in Kaidun – it is far easier for these smaller objects to scatter throughout the solar system than it is for larger, conventionally-sized meteorites.
We suggest that the final parent object where Kaidun was assembled was a large body with a C-type asteroid signature – possible asteroid 1-Ceres or the martian moon Phobos.