Do Martian slopes with Recurring Slope Lineae (RSL) have a distinct topographic signature?

Recurring Slope Lineae (RSL) are dynamic, low-albedo, slope-parallelsurface features on Mars that occur mainly on steep (>25°)slopes. RSL typically display seasonal dynamics as they appear duringlate Martian spring, progressively grow during summer, and subsequentlyfade as summer ends. RSL formation mechanisms remain under debate withproposed mechanisms involving either water/brines ("wet theories") vs.dry granular flows within a surficial dust layer ("dry theories"). In anattempt to distinguish between plausible RSL mechanisms, this studycompares the topographic and morphologic characteristics of hillslopeswith and without RSL. We suggest that a distinct topographic signaturefor RSL hillslopes would argue against the "dry" RSL mechanisms, as RSLdynamics within a thin dust layer are not expected to significantlyimpact the hillslope-scale topography. In contrast, the presence offluids on RSL hillslopes could conceivably accelerate rock weatheringrates, which in turn may impact the hillslope-scale topography. Ouranalyses are based on HiRISE, CTX and HRSC digital terrain models (DTMs)together with geomorphic mapping using high-resolution orbital images.We focus on inner crater hillslopes and compare the topographiccharacteristics of RSL vs. non-RSL slopes. In addition, in order toaccount for the potential influence of aspect-dependent solarirradiation on hillslope processes, we also applied our analysis onadjacent "control" craters that are devoid of RSL activity. Preliminaryresults from Palikir (-41.6°/ 202.1°E) and Rauna (35.2°/328°E) craters reveal that the topographic slope distribution alongcrater walls with RSL activity is distinct from the slope distributionalong crater walls which are devoid of RSL activity. Our results appearto support increased rock-weathering rates on crater walls thatpresently experience RSL activity.