New evidence for climate and erosion history in Gale crater, Mars, from Curiosity’s ascent onto the Greenheugh pediment

International audience; Curiosity’s southward traverse up the lower north slope of Mt. Sharp (in Gale crater, Mars) and across Glen Torridon has brought it in contact with the organics-bearing sediments of the Knockfarril Hill member, the light-toned, nodule-rich strata found at Western, Central, and Tower buttes, and to the abrupt truncation of these altered Murray sediments at the Greenheugh pediment. Curiosity ascended the steep northern edge of the Greenheugh pediment near Tower butte, thus accessing strata identified ~20 years ago as recording a major environmental transition in the history of Gale. The basal truncation surface of the pediment is the Siccar Point group (SPg) basal unconformity, which extends past Vera Rubin ridge (VRR) to the north. Above the unconformity lies a