20-EPN2-067: Hydrogen isotope compositions of matrices in unequilibrated ordinary chondrites
Visit by Helen Grant, University of Manchester (UK) to TA2.9 Ion Probe Facility (IPF), CRPG (France).
Dates of visit: 10-21 October 2022
Report Summary: One way to study the origin of water and other volatiles which accreted onto rocky planets such as Earth during the formation of the Solar System is to study meteorites that fall from asteroids and other planetary bodies. Hydrogen isotope ratios within meteorites can be used as a tracer for the source of a body’s water, and to an extent spatial and temporal information about the formation of parent bodies.
Previously, we measured the D/H ratios of bulk powders of a wide range of unequilibrated ordinary chondrites (UOCs), and found wide variations which did not fit into current H-distribution models. Using SIMS, we measured the H, D, C, and Si contents of the fine-grained matrix of 13 of these previously studied UOCs (only falls) ranging from types 3.00 – 3.9. Preliminary results confirm the wide previously observed spread of D/H ratios between samples, including high elevations in a handful of UOCs. C/H ratios will be used to determine the D contribution within samples specific to water, however initial observations confirm contributions from both hydrated and organic components. The results from this visit will be combined with other in-situ studies carried out at the home institution to determine exactly what phases are hosting this highly D-rich material, and how these chondrites affect models of water transport in the early Solar System.
Read the full scientific report, with kind permision from Helen Grant.
