A HEMISPHERICALLY INTEGRATED SEDIMENTARY GEOLOGICAL SYSTEM AT NILI FOSSAE, MARS
The most complete outcrop sections of the Nili Fossae stratigraphy occur in the NE Syrtis region that lies adjacent to Jezero crater, exposing many of the regionally observed deposits of diverse hydrous alteration minerals, megabreccia, layered sulfates, and Hesperian lavas. Sedimentological work on Jezero crater and recent work suggesting a pyroclastic origin for the regional olivine-rich unit shows well-understood sedimentary processes are recorded in Nili Fossae. The sedimentary processes of impact gardening facilitated three or more generations of crustal recycling. Basement megabreccia may therefore record formation of the Borealis and Isidis basins as well as Jezero’s excavatation of deep Noachian crustal materials and their subsequent deposition in the vicinity of NE Syrtis. Collectively, the Nili Fossae stratigraphy may act as a key reference section for lithologies distributed across the planet’s surface. In situ examination of the two above Mars 2020 sites, or of a site midway between them, would provide a well-chracterized tiepoint for this sedimentary reference section.