20-EPN2-102: A new source of water from Mars
Visit by Tim Tomkinson, University of Bristol (UK) to TA2.9 Ion Probe Facility (IPF), CRPG (France).
Dates of visit: 05-09 December 2022
Report Summary: Here we have searched for a source of D-enriched Martian groundwater previously discovered in the Martian meteorite Lafayette (up to δD 4725‰) within olivine defects below the secondary mineral phyllosilicate. These groundwaters which are known flowed through this sample 670 Ma were sourced from the Martian atmosphere, or had equilibrated with it, and diffused up to ~1.5 µm into the olivine via shock-formed defects in vein walls. In this project we want to determine a calibration line to resolve the water content on the Martian olivines and find a potential location of new water within the defects.
Two 1 inch indium mounts were prepared with olivine plus glass standards and paired Martian nakhlite samples (Yamato 593, 802, 749, Lafayette and Nakhla) to confirm this source of Martian ground water. Work was conducted with Dr Johan Villeneuve and Dr Laurette Piani on the Cameca IMS 1270 E7 ion probe at CRPG, Nancy. The new obtained/formed standards provided calibration to measurements of water contents (H2O%) within the Martian olivines and when combined with standards from CRPG δD values were roughly constrained. Owing to the unique surfaces of each Martian altered olivine it was impossible to confirm pre analyses if defects hosting water would be present in the outer olivine surfaces. Results show a location where an enriched δD was present, further investigations such as Transmission Electron Microscopy (TEM) are required to confirm this.
