Roger C. Wiens*, Arya Udry, Olivier Beyssac, Cathy Quantin, Nicolas Mangold, Agnes Cousin, Lucia Mandon, Tanja Bosak, Olivier Forni, Scott McLennan, Violaine Sautter, Adrian Brown, Karim Benzerara, Jeffrey R. Johnson, Lisa Mayhew, Sylvestre Maurice, Ryan B. Anderson, Samuel M. Clegg, Larry Crumpler, Travis S. J. Gabriel, Patrick Gasda, James Hall, Briony Horgan, Linda Kah, Carey Legett IV, Juan Manuel Madariaga, Pierre-Yves Meslin, Ann M. Ollila, Francois Poulet, Shiv Sharma, Sandra Siljeström, Justin I. Simon, Tayro Acosta-Mayeda, Cesar Alverez-Llamas, S. Mike Angel, Gorka Arana, Pierre Beck, Sylvain Bernard, Tanguy Bertrand, Bruno Bousquet, Kepa Castro, Baptiste Chide, Elise Clavé, Ed Cloutis, Stephanie Connell, Erwin Dehouck, Gilles Dromart, Woodward Fischer, Thierry Fouchet, Raymond Francis, Jens Frydenvang, Olivier Gasnault, Erin Gibbons, Libby Hausrath, Xavier Jacob, Hemani Kalucha, Evan Kelly, Nina Lanza, Javier Laserna, Jeremie Lasue, Ralph Lorenz, Jesus Martinez-Frias, Stephane Le Mouelic, Richard Leveille, Guillermo Lopez Reyes, Noureddine Melikechi, Jose Antonio Manrique, Tim McConnochie, David Mimoun, Franck Montmessin, Javier Moros, Naomi Murdoch, Cedric Pilorget, Patrick Pinet, William Rapin, Clement Royer, Fernando Rull, Susanne Schroeder, Alex Stott, Jesse Tarnas, Nathalie Turenne, Marco Veneranda, David Vogt, Peter Willis, Kathryn M. Stack, Kenneth H. Williford, Kenneth A. Farley, and the SuperCam team, Science Advances, 2022, 8, 1-16

Abstract

Before Perseverance, Jezero crater’s floor was variably hypothesized to have a lacustrine, lava, volcanic airfall, or aeolian origin. SuperCam observations in the first 286 Mars days on Mars revealed a volcanic and intrusive terrain with compositional and density stratification. The dominant lithology along the traverse is basaltic, with plagioclase enrichment in stratigraphically higher locations. Stratigraphically lower, layered rocks are richer in normative pyroxene. The lowest observed unit has the highest inferred density and is olivine-rich with coarse (1.5 millimeters) euhedral, relatively unweathered grains, suggesting a cumulate origin. This is the first martian cumulate and shows similarities to martian meteorites, which also express olivine disequilibrium. Alteration materials including carbonates, sulfates, perchlorates, hydrated silicates, and iron oxides are pervasive but low in abundance, suggesting relatively brief lacustrine conditions. Orbital observations link the Jezero floor lithology to the broader Nili-Syrtis region, suggesting that density-driven compositional stratification is a regional characteristic.