Late‐Stage Debris Flows Eroded Aeolis Mons in Gediz Vallis, Gale Crater, Mars

Abstract How the ancient climate of Mars transitioned to its current cold, hyperarid state is recorded by the sedimentary rocks preserved on its surface. Gale crater, the Curiosity rover landing site, is one such location, where the central mountain, Aeolis Mons, preserves an extensive sedimentary record. Curiosity has demonstrated that the Aeolis Mons succession comprises older, fluvio‐lacustrine facies overlain by younger, aeolian facies, inferred to reflect a broad aridification trend. From orbit, multiple canyons and sediment fans are observed originating from Gale's crater rim and Aeolis Mons itself, suggesting regional, intermittent returns to wet conditions, late in the crater's history. Curiosity recently investigated Gediz Vallis, a canyon incised into Aeolis Mons, which contains a central ridge hypothesized to be a degraded alluvial fan. We use C uriosity 's remote sensing suite to test this orbital hypothesis, by investigating the characterizing these canyon‐filling, sedimentary deposits in an upslope region of Gediz Vallis, Arc Pass. Here, the rover conducted an extensive campaign and was able to resolve fine‐scale sedimentary facies and textures. We find these deposits consist of transported breccias and conglomerates, and record multiple sediment transport processes, including debris flows and landslides, separated by episodes of aeolian erosion and in‐situ alteration. The debris flow deposits, preserved as levees and channels, require the continued, but likely intermittent, surface water availability, during the exhumation phase of Aeolis Mons, late in the history of both Gale crater and Mars. The processes recorded here are likely to be representative of regional, paleoclimatic conditions across Gale crater.