EXPLORING THE JAU CRATER CLUSTER, GALE CRATER, MARS.

The Jau crater cluster on the north flank of Mt. Sharp in Gale crater consists of 20 to 3023 simultaneously formed impact structures. The craters are ~2 m to ~25 m across (generally24 increasing in size from the ESE to WNW). Using Digital Terrain Models derived from orbital and25 rover orthomosaics of two of the larger craters, we evaluated the amount and processes of26 degradation based upon current versus expected original crater morphology. We conclude that the27 craters in the cluster are the result of a fragmenting primary impactor and that predominantly28 aeolian degradation at these two craters is responsible for ~1-2 m wall back-wasting, 10s of cm of29 infilling by aeolian drift, and 20-40 cm rim lowering. Other craters in the cluster experienced30 similar degradation whose expression varied according to crater size: smaller-scale morphology at31 smaller craters is more modified by a given amount of erosion. Prevailing winds erode the32 downhill, NNE side of the craters more though raised rims persist at the larger craters. An33 estimated vertical erosion rate of 0.1 m/Myr and horizontal erosion rate of several m/Myr predicted34 by others appears most consistent with the Jau crater morphology and setting relative to erosion35 estimates for elsewhere in Gale crater and other Mars landing sites. Factoring in uncertainties in36 our estimates, these rates are broadly consistent with the scale of erosion inferred for evolution of37 larger, older features on Mt. Sharp and suggest the cluster-forming impact occurred one to a few38 and less than ~5 Ma.