Carbon Isotope Abundance in Meteoritic Carbonates.

@article{Clayton1963CarbonIA,
  title={Carbon Isotope Abundance in Meteoritic Carbonates.},
  author={Richard N. Clayton},
  journal={Science},
  year={1963},
  volume={140 3563},
  pages={192-3}
}
The C(13)/C(12) ratio in the carbonate minerals of Orgueil, a carbonaceous chondrite, is 6 percent greater than the ratio in any known terrestrial carbon. The effect may be produced by a chemical isotope fractionation involving processes not common on earth, or it may be the result of incomplete homogenization of substances with different histories of nucleosynthesis.