Deciphering the Formation and Modification of Sediment Fans on Mars with Orbital and Rover Data

Summary

Numerous sedimentary rocks and sediment fans have been observed from orbit on the surface of Mars, which are indicators of a past climate that could support liquid water and possibly life.

This project will use remote sensing data, supplemented by data from ESA’s ExoMars rover, to characterise the formation environment of different sediment fans on Mars and determine how their formation processes changed throughout time. 

Description

Since the arrival of the Mars Reconnaissance Orbiter (MRO) in 2006, we have been living in a golden age of Mars exploration. There is now complete coverage of the surface of Mars at ~ 5 m/pixel and partial coverage up to a maximum of ~ 25 cm/pixel.

This revolution in image coverage has revealed a huge diversity in sedimentary rocks and landforms across the surface (eg Malin and Edgett, 2001), such as sediment fans, which suggest the past climate and environmental conditions differed from the cold and hyperarid desert we can see today.

Sediment fans (eg alluvial fans and deltas) are depositional landforms that usually form at breaks in slopes or at the margins of basins and are key indicators of a past climate that was able to sustain liquid water (eg Di Achille and Hynek, 2010; Rice et al., 2013; Fawdon et al., 2018). They are found on both ancient (~ 3.7 billion years old) and geologically recent Martian surfaces, suggesting their formation may have been recurrent throughout Mars’ history.

Although grain size cannot yet be resolved from orbit, Mars’ low erosion rates mean that the geomorphology and structure of many ancient landforms is preserved, which can still reveal much about their formation environment by comparison with analogous features on Earth.

Both the upcoming NASA Mars 2020 and ExoMars rovers have sediment fans within their landing zones; understanding their formation environment will be crucial for characterising the ancient martian climate.

The objectives of this project are to understand the formation and modification of sediment fans on ancient and geologically recent surfaces across Mars, specifically:

1. Examine the formation of stepped fans and associated valley-fill deposits along the Martian dichotomy and characterise their formation environment.
2. Investigate the distribution, morphology, and composition of sediment fans (likely both alluvial and deltaic) within the Valles Marineris canyon system to determine whether their formation was intermittent and the implications for the local climate and tectonic regime.
3. Study glacial and gulley features in the mid-latitudes to identify sediment fans and their associated fluvial or glacio-fluvial formation processes.
4. Characterise local sedimentary outcrops observed by ESA’s ExoMars rover at Oxia Planum and their relationship to regional sediment fans.

The student will learn to use high resolution imagery from the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) instruments to produce 3D digital terrain models (DTMs) and how to process hyperspectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument. This will be done using industry standard GIS software (ArcGIS, ENVI, Socet Set).

The student will also have access to newly acquired colour CaSSIS images through two supervisors who are science team members.

The student will also potentially work with images acquired by ESA’s ExoMars 'Rosalind Franklin' 2020 rover mission, through the supervisors’ involvement in the Panoramic Camera (PanCam) instrument.

Eligibility

Projects are funded for 3.5 years as an STFC studentship, which will cover all fees and a student stipend if you are from the UK, or from the EU and meet residency requirements (settled status, or 3 years full-time residency in the UK). For full details on what is covered by the studentship please see the STFC guidance.

For informal enquiries or further information, please contact Dr Joel Davis.

How to apply

Deadline: Friday 28 February 2020

Please send the following documents to Anna Hutson at postgradoffice@nhm.ac.uk

• Curriculum vitae
• Covering letter outlining your interest in the PhD project, relevant skills training, experience and qualifications, and a statement of how this PhD project fits your career development plans.
• Transcripts of undergraduate and Masters’ degree results.
• Two academic references including (if applicable) Masters’ project supervisor.

Interview date: March 2020

Start date:          October 2020