Chondrite normalization oxygen isotopes

As we will see, some anomalies in the isotopic composition of carbon, hydrogen and oxygen can be explained on the basis of this assumption, and we will start the discussion with the deuterium-rich matter in carbonaceous chondrites. This deuterium-rich matter is essentially present as complex macromolecules 70 73 96 97). The carbon in these samples is essentially normal 76,98). For some polymer-type fractions, the deuterium content is up to 32 times higher than the galactic value (D/H 2 x 10s in the number of atoms per cubic centimeter). High deuterium enrichments are known in interstellar molecules and the mechanism of this enrichment is fully understood. For an excellent review dealing with interstellar chemistry, see the paper by Winnewisser 99) and the previously mentioned book by Duley and Williams 13). 

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