Aeolian disruption and reworking of TARs at the Zhurong rover field site, southern Utopia Planitia, Mars

Abstract

Aeolian bedforms are the signatures of wind interaction with unconsolidated, granular surface materials. Transverse aeolian ridges (TARs) are widely distributed on Mars but their formation remains enigmatic. China's Zhurong rover explored four crescent-shaped TARs, with two horns generally facing south, during the first 107 sols in southern Utopia Planitia, Mars. Rover images show that these bedforms have distinct light and dark variations on their surfaces that likely result from the combination of a bimodal distribution of particle sizes and the crust formed by the accumulation of aeolian dust. Two of these bedforms exhibit erosional forms on their west sides, where megaripples facing in a direction different from that of the crescentic bedforms they disrupt were created by more recent winds from the northeast. Differing erosional configurations of each of these bedforms in close proximity to each other are probably related to the angle between the bedform crest and the wind direction, and may further suggest that erosion of TARs starts from their two flanks. Secondary ridges of TARs widely recognized on Mars could be megaripples formed during this erosion process. At the Zhurong landing site, TARs degraded into megaripples, suggesting that they might share similar formation and evolution mechanisms there and elsewhere on Mars.