Figure 5.

Comparison of the estimated H isotopic compositions of water in various chondrites with those for water in comets and Saturn's moon Enceladus (after [23]). The CI, CM and Tagish Lake isotopic compositions are clearly distinct from those measured for outer Solar System objects. The CR composition overlaps with those of the most D-poor comets. Surprisingly, the water in ordinary and R chondrites has H isotopic compositions that resemble those of most comets and Enceladus. However, this does not necessarily mean that the ordinary and R chondrites come from the outer Solar System. It is more likely that the H isotopic compositions of their water has been fractionated by parent body processes (see the text for details). This parent body fractionation may also have affected the carbonaceous chondrites, particularly the CRs.