The abundance and isotopic composition of water in eucrites

Volatile elements play a key role in the dynamics of planetary evolution. Extensive work has been carried out to determine the abundance, distribution, and source(s) of volatiles in planetary bodies such as the Earth, Moon, and Mars. A recent study showed that the water in apatite from eucrites has similar hydrogen isotopic compositions compared to water in terrestrial rocks and carbonaceous chondrites, suggesting that water accreted very early in the inner solar system given the ancient crystallization ages (similar to 4.5 Ga) of eucrites. Here, the measurements of water (reported as equivalent H2O abundances) and the hydrogen isotopic composition (delta D) of apatite from five basaltic eucrites and one cumulate eucrite are reported. Apatite H2O abundances range from similar to 30 to similar to 3500 ppm and are associated with a weighted average dD value of -34 +/- 67 parts per thousand. No systematic variations or correlations are observed in H2O abundance or dD value with eucrite geochemical trend or metamorphic grade. These results extend the range of previously published hydrogen isotope data for eucrites and confirm the striking homogeneity in the H-isotopic composition of water in eucrites, which is consistent with a common source for water in the inner solar system.