The Upper Gediz Vallis Ridge at Gale Crater: Sedimentary Rock Clasts Transported by a LateStage Debris Flow on Mars?

The Mars Science Laboratory (MSL) Curiosity rover continues to ascend Aeolis Mons in Gale crater, Mars, with the goal of characterising formerly habitable palaeoenvironments. Since September 2022, Curiosity has been traversing Gediz Vallis, a ~9km long canyon incising into sulfatebearing, sedimentary rocks on the northern margins of Aeolis Mons. Along the Gediz Vallis floor is the upper Gediz Vallis Ridge (uGVR), a quasisinuous, ~1.5 km long, ~80100 m wide, ~530 m high, ridge. Upslope, uGVR is clearly set within an erosional channel, which disappears downslope. Near the Gediz Vallis outlet, uGVR transitions into the broader, lower GVR, recently interpreted by Bryk et al. (2023, AGU Fall Meeting) as a degraded alluvial fan. Since entering Gediz Vallis, Curiosity has undertaken an extensive longdistance imaging campaign of the eastern uGVR flank, acquiring multiple Mastcam and ChemCam Long Distance Remote Micro Imager (LDRMI) mosaics. Additionally, in August 2023, Curiosity approached the ridge margins and conducted an insitu investigation (“Region B”). A major objective of Curiosity’s uGVR campaign is to the determine the primary depositional conditions and palaeoenvironment of the ridge, which may record evidence for latestage surface water flow in Gale.