The D/H ratio of the Martian Mantle: Evidence from the Lafayette MeteoriteOPEN ACCESS
Lydia J. Hallis, Evangelos Christou, Jemma Davidson, Andrea G. Distel
Advances in Geochemistry and Cosmochemistry
19 December 2025
“Hydrous apatite in the nakhlite group of martian meteorites shows evidence of Cl-rich fluid incorporation into the magma prior to apatite crystallisation. Thus, nakhlite apatite D/H ratios should reflect a mixture between the parental magma and this crustally derived fluid. Here we present the volatile content and D/H ratios of apatite within the nakhlite Lafayette (δD 137 to 352‰), suggesting mixing between a crustally derived Cl-rich fluid and an intermediate D/H ratio (δD ≈ 400‰) and a magma with a low D/H ratio (δD ≈ −100‰). This martian mantle D/H ratio is similar to that of Earth’s upper mantle, but is higher than recent D/H ratios measured within a number of other inner Solar System materials. Thus, D/H ratio heterogeneity in these materials points towards multiple sources of hydrogen during the formation of rocky planetary bodies in the inner Solar System.”
