Joel Davis

PhD project title:

Palaeoenvironmental Reconstructions on Mars

Project description:

There is compelling evidence that the atmosphere and climate of Mars have affected the global distribution of water on the planet. Both early Earth and Mars probably had atmospheres rich in carbon dioxide, but followed divergent evolutionary paths. The Earth became a world of nitrogen, oxygen, and life, whereas at about the same time Mars lost much of its atmosphere, and possibly its habitability. Martian geomorphology and stratigraphy provides a rich record of the palaeoclimate of the planet, revealing secular changes in the surface environment over a range of timescales. My project concerns the early evolution of Mars, when water probably played a significant role in shaping the surface environment.

The resolution of satellite imagery coming back from Mars means that metre-scale features can now be resolved, revealing the surface geology in unprecedented detail. My work uses these high resolution data to construct 3D digital terrain models (DTMs) using industry standard software to examine the structure, geomorphology and stratigraphy of the surface geology, in order to reconstruct the environmental history.

Specifically, my research looks at two main areas of Mars, with a focus on former fluvial, deltaic, and lacustrine environments. The first area, Arabia Terra, is an ancient region of the Mars’ southern highlands, generally considered one of the oldest regions on the planet. Arabia Terra is unusual, because unlike other ancient regions of Mars, it appears poorly dissected by the famous “valley networks” and may have been devoid of pluvial and fluvial activity. The absence of valley networks on such an old terrain has led many to speculate that Mars may have never been “warm and wet”, and that valley network formation elsewhere was driven by the melting of large ice sheets, the so-called “icy highlands” scenario.

Understanding the geological history of Arabia Terra is of increasing importance; the three remaining candidate landing sites for the UK-supported ExoMars rover are all located within or bordering Arabia Terra. Rather than valley networks, the widespread abundance of fossilised river systems – inverted fluvial channels – may shed light on the region’s climatic history. This work will feed into the understanding of the region (and early Mars, more generally) prior to the rover landing in 2021. Separately, I am also involved in the geological characterisation of two of the ExoMars landing sites.

The second area my project focus on is an enclosed topographic depression within Mars’ Valles Marineris canyon system, the south-western Melas Chasma basin. The south-western Melas basin is hundreds of millions years younger than Arabia Terra and shows an abundance of fossilised fluvial, deltaic, and lacustrine features. This project will aim to systematically map the surface geology of the Melas basin in order to better understand its complex aqueous history. Additionally, the Melas basin is considered a candidate landing site for NASA’s Mars 2020 rover mission, making understanding the evolution of the basin a high priority.


Davis, J.M., M. Balme, P.M. Grindrod, R.M.E. Williams and S. Gupta, 2016, Extensive Noachian fluvial systems in Arabia Terra: implications for early martian climate, Geology (in press).

Brough, S., B. Hubbard, C. Souness, P.M. Grindrod, and J. Davis, 2015, Landscapes of polyphase glaciation: eastern Hellas Planitia, Mars, Journal of Maps, v. 2015, p. 1-13.

Contact Details:
Supervisors: Peter Grindrod (Birkbeck), Matt Balme (Open University), Sanjeev Gupta (Imperial), Adrian Jones (UCL)