20-EPN2-092 Characterising fine-grained rims in CO chondrites to understand the mineralogy of the protoplanetary disk
Visit by Enrica Bonato, Deutsche Zentrum für Luft und Raumfahrt (DLR), Institute for Planetary Research (Germany) to TA2 Facility 3 – NHM Petrology, Mineralogy and Chemistry Facility (UK).
Dates of visit: 1-17 February 2022
Report Summary: Carbonaceous chondrites meteorites are amongst the most primitive extra-terrestrial materials available for study and can be used to understand the formation and evolution of the solar system, as they preserve components that formed and evolved in the protoplanetary disk. They are constituted by chondrules, Calcium and aluminum rich inclusions (CAIs), amoeboid olivine aggregates (AOAs) set within a fine-grained matrix.
Matrix material can be divided in two components: inter-chondrules matrix and fine-grained rims (FGRs) which envelopes chondrules. A major question is the understanding of the relationship between these two components, as a recent study on Te and Cr isotopes concluded that they formed from different precursor materials and therefore in different locations of the protoplanetary disk. Some of the most primitive CO3s like DOM08006, NWA7892, MIL090010 were analysed with SEM-EDX and EMPA.
A novel approach for characterisation of the modal mineralogy of the FGRs it was used in this project, which involves chemical modelling based hyperspectral imaging techniques for scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS).Moreover, preliminary interpretation of the EMPA chemical data of the FRGs were compared with data collected on the inter-chondrule matrix of the same meteorites. FGRs appears to be consistently richer in FeO throughout the petrologic range in comparison to inter-chondrule matrix, while MgO and Cr2O3 content is very similar.
