Astrobiology and the Torridonian

Mars is thought to have been habitable early throughout its history (>3 billion years
ago), when it sustained an atmosphere and stable bodies of liquid water at its
surface. Although the surface of Mars is now entirely inhospitable, traces of a
putative biosphere may be archived within its sedimentary rock record. The potential
of finding fossilised traces of life on Mars has been the driving force behind its
exploration for several decades, and continues with the NASA Curiosity and
Perseverance rovers, which are currently exploring Gale and Jezero craters. A
recent discovery by Perseverance of organic matter associated with reduced mineral
phases in the Neretva Vallis river channel has stimulated new interest in the
possibility of a Martian biosphere, and these materials have been sampled for
eventual return to Earth.
Until we achieve Mars Sample Return, developing hypotheses about Mars’ early
habitable history requires us to harness understanding of similar localities here on
Earth; we term such setting ‘planetary field analogues’. In this talk, I will discuss the
importance of planetary field analogues for understanding ancient Martian
environments, and consider how exceptionally well-preserved fossiliferous
sedimentary rocks from the Torridon Group of NW Scotland provide insights into
potential habitable environments on early Mars and the types of biosignatures for
which we might search following the sophisticated laboratory analysis of Martian
samples brought to Earth in the future.

Keyron Hickman Lewis, GSG Grant Awardee, School of Natural Sciences, Birkbeck College, London

Keyron has been a Research Assistant (2019–2020) , CNRS Orléans (France) and Università di Bologna (Italy)

Aurora Research Fellow (2021–2024), Natural History Museum, London

Research Fellow (2024–2024) , Imperial College London

and from 2024 a Lecturer in Planetary Exploration, Birkbeck, University of London

His research interests are

Co-evolution of Earth and Life in the Precambrian: can we constrain the emergence of major microbial metabolisms throughout the Precambrian and their relationship with changing sedimentary environments and ocean chemistry?

Modern analogues of ancient ecosystems: How can we use extreme planetary field analogues most effectively to explain geological and ecological aspects of environments on the early Earth and Mars?

Technique development: How can we harness non-traditional and emerging instrumentation and data treatment (e.g. chemometrics) to shed new light on the ancient fossil record?

Planetary exploration: How can we effectively utilise space mission observations, including rover and orbiter datasets, to reconstruct past environments and habitability throughout the Solar System?