Preservation of Organic Carbon Compounds and Potential Biosignatures by Reactive Iron Minerals on Mars


   School of Biological & Environmental Sciences

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  Dr C Schroeder, Dr I Hutchinson  No more applications being accepted  Funded PhD Project (UK Students Only)

About the Project

Mars is known as the Red Planet because of its dust-covered surface containing iron oxide pigments. In fact, Mars' mantle and crust contain a higher proportion of iron than Earth's. We now know that Mars was much more Earth-like - water-rich and habitable - during the Noachian period more than 3.5 billion years ago. At that time, life had originated on Earth and the question whether there was ever life on Mars drives the international Mars exploration programme. Organic molecules as potential biosignatures or indicators of prebiotic chemistry are difficult to preserve over such timescales. On Earth, over 20% of organic carbon in sediments is directly bound to reactive iron minerals. Reactive iron minerals and organic compounds mutually stabilize each other over long timescales but are eventually degraded by diagenetic processes. On Mars, ancient sedimentary rocks contain abundant reactive iron minerals: Nanophase iron oxides have been identified with Mössbauer spectroscopy on board the Mars Exploration Rovers (MER) Spirit and Opportunity; iron-rich X-ray amorphous phases were identified with X-ray diffraction (XRD) on board the Mars Science Laboratory (MSL) Curiosity rover. However, ongoing (e.g. the Mars 2020 Perseverance rover) and future missions (e.g. the Rosalind Franklin rover or the Martian Moons Explorer) use Raman spectroscopy as their primary tool for mineralogical information, and it is unclear how to recognize reactive iron minerals with Raman spectroscopy. Here we will cross-reference reactive iron mineral occurrences at the MER and MSL landing sites to provide criteria for the selection of sedimentary rock targets with the highest organic carbon preservation potential that can be applied to other missions. Through investigation of relevant Mars-analogue material in the lab with Mössbauer spectroscopy, XRD and Raman spectroscopy we will determine the optimum Raman measurement parameters to be able to identify reactive iron miner


Chemistry (6) Geology (18)

Funding Notes

This PhD studentship is funded by the UK SDpace Agency.
The project starts 1 October 2024.
Funding is provided for 3.5 years and provides the following package of financial support:
- A tax-free maintenance grant set at the UK Research Council’s national rate, which in 2023/24 is £18,622;
- Payment of tuition fees at the Home rate;
- Access to research support funding

References

Bonsall, E., M. McHugh, H. Lerman, I. Hutchinson, and C. Schröder (2022), Reactive iron mineral phases may preserve organic carbon on Mars: Implications for Raman spectroscopy, Lunar and Planetary Science 53, 2148, 7-11 March 2022, The Woodlands, Texas, USA, https://www.hou.usra.edu/meetings/lpsc2022/pdf/2148.pdf.
Dugdale, A., N.K. Ramkissoon, P. Fawdon, M.R. Patel, L. Hills, G. Degli-Alessandrini, E. Bonsall, C. Schröder, S.M.R. Turner, C.N. Achilles, and V.K. Pearson (2023), SOPHIA: A mineralogical simulant for phyllosilicate terrains at the Rosalind Franklin landing site, Oxia Planum, Mars, Icarus 400, 115568, https://doi.org/10.1016/j.icarus.2023.115568.
Morris, R.V., C. Schröder, G. Klingelhöfer, and D.G. Agresti (2019), Chapter 27: Iron Mineralogy, Oxidation State, and Alteration on Mars from Mössbauer Spectroscopy at Gusev Crater and Meridiani Planum. In: J.L. Bishop, J. Moersch and J.F. Bell III (eds.), Remote Compositional Analysis: Techniques for Understanding Spectroscopy, Mineralogy, and Geochemistry of Planetary Surfaces, pp. 538-554, Cambridge University Press, https://dx.doi.org/10.1017/9781316888872.029

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