B5 - Early-formed, volatile clasts in meteorite breccias: buildung materials of the terrestrial planets ?
Currently in our meteorite collections, we possess many different meteorites that can help us to resolve the formation and evolution of the solar system and planetary body. For our project it is of great interest why the terrestrial planets contain many volatile elements (e.g. hydrogen, oxygen etc.) even though the inner solar system was depleted in volatile-elements. For that, the B5-project takes a closer look in volatile-bearing meteorites moreover, volatile-rich xenoliths that are found in a whole range of meteorite types (achondrites and chondrites). Ultimately we want to gain more information in whether these xenoliths might resemble volatile-rich parent bodies that we do not have currently present in our meteorite collections as individual rocks. The presence of the volatile-rich xenoliths (outer solar system) in achondritic meteorites (inner solar system) might also harbor important information regarding the impact and mixing processces.
In this project, we will characterize and subdivide the different kind of volatile-rich clasts into different types. Detailed mineral information will be gathered by electron microprobe (EPMA), scanning electron microscope (SEM), and LA-ICP-MS. Furthermore, high resolution in situ SIMS and NanoSIMS isotopic data of O, H, S, and bulk O and Cr will be acquired in combination in cooperation with the NordSIMS institute at the Natural History Museum Stockholm, Sweden (SIMS) and the MPI in Mainz (NanoSIMS).
The results so far, show that we can distinguish two main types of volatile-rich clasts. The CI-like type and CM-like types. The mineralogy and the thermal histories obtained by Raman spectrscopy of these clasts is similar to those of CI chondrites and CM chondrites, respectively.
Which would suggest that the clasts experienced similar formation histories and are of the same material. However, the isotopic systems suggest otherwise. The CI or now categorized as C1 clasts show dichotomies that all isotopic systems have that have so far been analyzed (S, O, H).
This in turn suggests that the C1 clasts sampled different isotopic reservoirs compared to the CI chondrites, and thus might originate from completely different parent bodies. Some questions still remain. However, we can already conclude that breccias can harbor material that so far was overlooked and point towards different volatile-rich parent bodies.
Visser, R., John, T., Patzek, M., Bischoff, A., Whitehouse, M. J., 2019: Sulfur isotope study of sulfides in CI, CM, C2ung chondrites and volatile-rich clasts - evidence for different generations and reservoirs of sulfide formation. Geochim. Cosmochim. Acta 261, 210-223. 10.1016/j.gca.2019.06.046
Ebert, S., Bischoff, A., Harries, D., Lentfort, S., Barrat, J. A., Pack, A., Gattacceca, J., Visser, R., Schmid-Beurmann, P., and Kimpel, S., 2019: Northwest Africa 11024—A heated and dehydrated unique carbonaceous (CM) chondrite. Meteorit. Planet. Sci. 54, 328-356. 10.1111/maps.13212
Visser, R., Menneken, M., John, T., Patzek, M., Bischoff, A., 2018: Temperature constraints by Raman spectroscopy of organic matter in volatile-rich clasts and carbonaceous chondrites. Geochim. Cosmochim. Acta 241, 38-55. 10.1016/j.gca.2018.08.037
Patzek, M., Bischoff, A., Visser, R., and John, T., 2018: Mineralogy of volatile‐rich clasts in brecciated meteorites. Meteorit. Planet. Sci, 53, 2519-2540. 10.1111/maps.13175