Monitoring aeolian bedform migration rates on Mars

• Main Author: Boazman, Sarah Jane
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UCL (University College London) 2022
• Subjects: North Pole; Valles
• Online Access: https://discovery.ucl.ac.uk/id/eprint/10142280/1/SN17115067_Sarah_Jane_Boazman_Monitoring%20Aeolian%20Bedform%20Migration%20Rates%20on%20Mars.pdf; https://discovery.ucl.ac.uk/id/eprint/10142280/

In recent years aeolian bedforms across the surface of Mars have been monitored, however, the boundary conditions that control bedform migration rates in different topographical and environmental settings are yet to be explored. Especially the effect of local conditions (topography, CO2 ice presence, and if bedforms are located on plains or within a crater) on bedform migration, in comparison to regional conditions. In this thesis I measured dune migration rates in three different environments, using images from the ConTeXt (CTX) and High Resolution Imaging Science Experiment (HiRISE) cameras on board the Mars Reconnaissance Orbiter (MRO), with software Co-Registration of Optically Sensed Images and Correlation (COSI-Corr) method. In Valles Marineris the topography of the valley caused fast slope winds, which converged with winds flowing through the valley allowing migration of 0.3m/EY of some of the tallest dunes (up to 180 m in height) on Mars. Near Scandia Cavi, near the north pole of Mars, CO2 ice stabilized linear dunes during the martian winter and lateral migration of the dunes occurred only in ice free seasons, of up to 2 m/EY. Fast circumpolar winds, combined with local topographic winds likely caused the fast migration rates. In the region surrounding landing sites of NASA’s Mars 2020 and ExoMars 2022 missions, I demonstrated craters can act as sediment traps by investigating three dune fields within craters near each landing site and measured migration rates varying from 0.5 m/EY to 5.6 m/EY. These three studies demonstrate that the local boundary conditions dominantly control the wind regimes present which can be complex, which in turn, control the bedform migration rates. Investigating the boundary conditions at future Mars landing sites would prove valuable by showing possible areas of aeolian erosion exposing fresh outcrops for sampling, which would further the understanding of the geomorphology and geology of Mars.