Imperial College London
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ProfessorMarkSephton

Faculty of Engineering, Department of Earth Science & Engineering

Professor of Organic Geochemistry
 
 
 
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Contact

 

+44 (0)20 7594 6542m.a.sephton Website

 
 
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Location

 

2.34Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Royle:2022:10.1089/ast.2021.0074,
author = {Royle, SH and Salter, TL and Watson, JS and Sephton, M},
doi = {10.1089/ast.2021.0074},
journal = {Astrobiology},
pages = {1--21},
title = {Mineral matrix effects on pyrolysis products of kerogens infer difficulties in determining biological provenance of macromolecular organic matter at Mars},
url = {http://dx.doi.org/10.1089/ast.2021.0074},
volume = {22},
year = {2022}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Ancient martian organic matter is likely to take the form of kerogen-like recalcitrant macromolecular organic matter (MOM), existing in close association with reactive mineral surfaces, especially iron oxides. Detecting and identifying a biological origin for martian MOM will therefore be of utmost importance for life detection efforts at Mars. We show that Type I and Type IV kerogens provide effective analogues for putative martian MOM of biological and abiological (meteoric) provenances respectively. We analyse the pyrolytic breakdown products when these kerogens are mixed with mineral matrices highly relevant for the search for life on Mars. We demonstrate that, using traditional thermal techniques as generally used by the Sample Analysis at Mars and Mars Organic Molecule Analyser instruments, even the breakdown products of highly recalcitrant MOM are transformed during analysis in the presence of reactive mineral surfaces, particularly iron. Analytical transformation reduces the diagnostic ability of this technique, as detected transformation products of both biological and abiological MOM may be identical (low molecular weight gas phases and benzene) and indistinguishable. The severity of transformational effects increased through: calcite < kaolinite < haematite < nontronite < magnetite < goethite. Due to their representation of various habitable aqueous environments and the preservation potential of organic matter by iron, it is not advisable to completely avoid iron-rich strata. We conclude that haematite-rich localities, with evidence of extensive aqueous alteration of originally reducing phases, such as the Vera Rubin Ridge, may be relatively promising targets for identifying martian biologically-sourced MOM.
AU  - Royle,SH
AU  - Salter,TL
AU  - Watson,JS
AU  - Sephton,M
DO  - 10.1089/ast.2021.0074
EP  - 21
PY  - 2022///
SN  - 1531-1074
SP  - 1
TI  - Mineral matrix effects on pyrolysis products of kerogens infer difficulties in determining biological provenance of macromolecular organic matter at Mars
T2  - Astrobiology
UR  - http://dx.doi.org/10.1089/ast.2021.0074
UR  - https://www.liebertpub.com/doi/10.1089/ast.2021.0074
UR  - http://hdl.handle.net/10044/1/94287
VL  - 22
ER  -
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