Directional Analysis of Fractures at ESA’s Rosalind Franklin landing site, Oxia Planum, Mars

Abstract

The Rosalind Franklin rover of the European Space Agency’s ExoMars program is going to land at Oxia Planum, Mars after its launch scheduled in 2030. The mission aims to look for evidence of past and present life on Mars. The presence of fractured rocks at the landing site is of interest to the astrobiological goal of the mission because fractures represent conduits that could facility circulation of fluids. Our study is devoted to observing the orientations of the fractures and to investigate their possible origin by single or multiple processes. We first selected 50 regions of interest (ROIs) in areas of pronounced fracturing, using images from the High-Resolution Imaging Science Experiment (HiRISE) as a basemap. We then analysed the orientation of the fractures and how it varied with length. Statistical analysis shows that fractures predominantly have an E-W orientation, especially in longer fractures, while shorter fractures have a more random pattern. These orientation trends suggest a geological history influenced primarily by both hydrofracturing and tectonic processes. The preferred orientation, which is consistent with north-south tectonic shortening structures documented in the vicinity of the region, is likely to reflect a regional tectonic event between 3.7 and 4.0 billion years ago. The origin of the fractures may have promoted the migration of subsurface fluids through the fractured bedrock, potentially creating habitable conditions for microbial life. Our first study on fractures supports other studies on the geology of the ancient terrains at Oxia Planum, which hides a complex geologic history needing to be unravelled from different perspectives.