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.
21-EPN-FT1-029: Petrographical, mineralogical and geochemical study of the meteorite Gueltat Zemmour Morocco, observed fall in August 2018.
Visit by El Mehdi El Hachimi, Hassan II University of Casablanca (Morocco) to TA2 Facility 3 – NHM Petrology, Mineralogy and Chemistry Facility (UK).
Dates of visit: 28 November -16 December 2022
Report Summary: The Gueltat Zemmour meteorite project was undertaken to conduct laboratory analyses using various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The XRD results were divided into two aspects: mineral identification and mineral quantification. The SEM technique was performed on two sections and provided EDS analyses of interesting mineral phases on the meteorite, as well as compositional and single element maps. The EPMA technique was used to analyze the major and minor element compositions of sulfide, silicate, and metal. The LA-ICP-MS technique was used to determine trace element compositions in areas of interest determined by SEM and EPMA, and no halite minerals were found. The analyses yielded numerous encouraging results, including 500 SEM spectra, 177 analyses for silicates, 69 for metal and sulfides from EPMA, and 48 analyses from LA-ICP-MS. Therefore, the results from SEM, XRD, EPMA, and particularly LA-ICP-MS appear to represent the completeness of the scientific data required to create a brilliant research article.
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21-EPN-FT1-021: Diffuse chemotrophic microbialites as analogues for martian life
Visit by Laura Clodoré, Centre de Biophysique Moléculaire-CNRS, Orléans (France) to TA2 Facility 3 – NHM Petrology, Mineralogy and Chemistry Facility (UK).
Dates of visit: 27 June – 05 July 2022
Understanding the characteristics and microbial-scale habitats of the oldest traces of life on Earth requires the use of multiple complementary methods that will be relevant both for in situ analysis of Martian rocks, as well as for identifying signatures of biological processes (biosignatures) in returned samples.
In this respect, fossilised chemolithotrophic microorganisms found in ancient volcanoclastic sediments from the East Pilbara craton, Western Australia, an environment having similar conditions to early Mars, can be used as analogues for the kinds of primitive microorganisms that could be found on Mars. We performed combined analyses using FTIR spectroscopy, SEM observations, EDX mapping and LA-ICP-MS in order to investigate the distribution and the molecular and elemental composition of the carbonaceous matter. These results will complete a detailed morphological, mineralogical and geochemical dataset and that will enable the assessment of the astrobiological potential of these Mars analogue sediments.
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20-EPN-080: Structural organisation and complexity of the Antarctic cryptoendolithic communities
Visit by Gerardo Antonio, Università degli Studi della Tuscia (Italy) to TA2 Facility 3 – NHM Petrology, Mineralogy and Chemistry Facility (UK).
Dates of visit: 15-19 March 2022
Report Summary: The Antarctic cryptoendolithic communities are microbial ecosystems that dominate the biology of most ice-free areas in Continental Antarctica and described for the first time in the McMurdo Dry Valleys, the largest ice-free area of the continent. The Dry Valleys are a nearly pristine environment largely undisturbed and uncontaminated by humans and show remarkable peculiarities, representing an important analogue for the conditions of ancient Earth and Mars and a model environment for astrobiological studies.
These ice-free areas are dominated mostly by oligotrophic mineral soil and rocky outcrops and, for the harshest conditions in this area, the biology is dominated by cryptic microbial life-forms dwelling inside rocks. These cryptoendolithic communities are complex and self-supporting assemblages of phototrophic and heterotrophic microorganisms, including Bacteria, Chlorophyta and both free-living and lichen-forming fungi.
Despite the recent molecular studies to investigate the biodiversity and community composition, the interaction microbes-microbes and microbes-rock matrix, the spatial organisation, rock microstructure (e.g. porosity, pore size and connectivity) are totally unexplored.
We, herein, are proposing to build an interactions network map, on colonized and not colonized sandstone, resolving the contributions of the different microorganisms and the relationships established among them and between microbial cells and the lithic substrate.