Periodic Bedrock Ridges at the ExoMars 2022 Landing Site: Evidence for a Changing Wind Regime

Abstract

Wind‐formed features are abundant in Oxia Planum (Mars), the landing site of the 2022 ExoMars mission, which shows geological evidence for a past wet environment. Studies of aeolian bedforms at the landing site were focused on assessing the risk for rover trafficability, however their potential in recording climatic fluctuations has not been explored. Here we show that the landing site experienced multiple climatic changes in the Amazonian, which are recorded by an intriguing set of ridges that we interpret as Periodic Bedrock Ridges (PBRs). Clues for a PBR origin result from ridge regularity, defect terminations, and the presence of preserved megaripples detaching from the PBRs. PBR orientation differs from superimposed transverse aeolian ridges pointing toward a major change in wind regime. Our results provide constrains on PBR formation mechanisms and offer indications on paleo winds that will be crucial for understanding the landing site geology.

Rivers and Lakes in Western Arabia Terra: The Fluvial Catchment of the ExoMars 2022 rover landing site

“…Figure 10). In CTX images, these terrains are predominantly dark in tone and either on the floor of impact craters associated with rimless crater lakes or large crater lakes (Figure 4a ridges (e.g., Favaro et al, 2021;Silvestro et al, 2021). These bands comprise a bright fringe at the edge of the feature, and a darker band inside, which transitions to a tone comparable to that of the surrounding plains in the centre of the feature.…”

Depositional Controls of the Layered Deposits of Arabia Terra, Mars: Hints From Basin Geometries and Stratigraphic Trends

“…AT is a large regional dichotomy which represents the transition between the southern highlands and the northern lowlands (Evans et al., 2010; Smith et al., 2001; Zuber et al., 2000) (Figure 1). Well known for a high density of craters, many of which contain ELDs (Cadieux & Kah, 2015; Day et al., 2019; Franchi et al., 2014; Pondrelli et al., 2019; Zabrusky et al., 2012), AT represents a unique geologic story which combines the dynamics of sedimentary deposition, erosion, crustal dynamics, explosive volcanism, and groundwater activity (Andrews‐Hanna et al., 2007, 2010; Bishop et al., 2008; Day et al., 2016; Evans et al., 2010; Lewis & Aharonson et al., 2014; Molina et al., 2017; Pondrelli et al., 2015; Salese et al., 2019; Silvestro et al., 2021; Whelley et al., 2021). These processes have produced a plethora of features including meandering valleys and deltas (Bishop et al., 2008; Molina et al., 2017; Salese et al., 2019).…”

Planetary Aeolian Landforms: An Introduction to the Fifth Planetary Dunes Workshop Special Issue

“…The ability of ripple and dune systems to record past wind conditions is another exciting line of research, and atmospheric models run at different orbital configurations are a powerful tool to that end (Fenton et al., 2018). Are climatic fluctuations recorded by the aeolian bedforms in Meridiani regional/global in nature (Silvestro et al., 2021)? More mapping efforts aimed at recognizing complex bedform patterns are needed to address this question.…”