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Favaro, Elena A.; Balme, Matthew R.; Mcneil, Joseph D.; Fawdon, Peter; Davis, Joel M.; Grindrod, Peter M. and Lewis, Stephen R.
(2024).
DOI: https://doi.org/10.1016/j.epsl.2023.118522
Abstract
Periodic Bedrock Ridges (PBRs) are repeating, symmetrical, wind-transverse, bedrock-abraded linear ridges that occur on Mars as parallel sets. Here, we extend our previous survey of PBRs at Oxia Planum – the landing site of ESA's ExoMars Rosalind Franklin rover – to include three additional sites along the margins of the circum-Chryse basin to understand patterns in PBR orientation and occurrence. We analyzed PBR crestline orientation at each study site and found them to be consistent across this large region, but their orientations do not align with global circulation model winds, suggesting contemporary winds are not responsible for PBR development. Furthermore, we used observations of landscape-level stratigraphic relationships at Oxia Planum to constrain the formation age of PBRs to be late Noachian to early Amazonian. Their consistent orientations and age suggest that the Chryse-margin PBRs formed concurrently and represent modification of an ancient palaeosurface. In addition, we find a tendency for PBRs to preferentially occur in regions where Fe/Mg-rich phyllosilicate minerals were detected in hyperspectral remote sensing data. We conclude that regional scale aeolian processes formed the circum-Chryse PBRs, and that exposed bedrock with Fe/Mg-rich phyllosilicate detections were either more susceptible to PBR formation, or better preserve PBRs than other regional lithologies.