The Kaidun meteorite: Interstellar diamond in the CR and CI carbonaceous components

Concentrations anti isotopic compositions of carbon, nitrogen, and noble ga ses were determined in interstellar diamond separated from the CR and CI ca rbonaceous components of the Kaidun meteoritic breccia. The diamonds in the CR and CI components were found to be very similar and resemble diamonds i n the Orgueil CI and Murchison CM2 chondrites. These facts indicate a homog eneous mixing of interstellar diamond grains of different populations in th e protoplanetary nebula, including in the area of formation of parent bodie s for CR meteorites. It is shown that the carbonaceous matter of the Kaidun meteorite suffered heterogeneous heating. i.e., some portions of the meteo rite did not experience long-term heating above 100 degreesC, which resulte d in preservation of all noble gas components in the diamond grains.