Refractory Inclusion

Inclusions found predominantly in carbonaceous chondrites and are rich in refractory elements particularly calcium, aluminum and titanium that in various combinations form minerals such as spinel, melilite, perovskite and hibonite. There are two types of refractory inclusion:

  1. Ca Al-rich inclusions (CAIs)
  2. Amoeboid olivine aggregates (AOAs)

Refractory inclusions were the first solids to condense from within the hot inner protoplanetary disk. As such, they provide evidence of the earliest thermal and chemical processing, as well as preserve the isotopic signatures of the presolar material within the dust and gas clouds that would later form the Sun and our planetary system. Their shape and textures vary from irregular structures suggestive of gaseous condensates, to more compact and rounded structures that may have derived from melts or partial melts that slowly cooled over a period of days.1