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Regolith of the crater floor units, Jezero crater, Mars: Textures, composition and implications for provenance

February 7, 2023

A multi-instrument study of the regolith of Jezero crater floor units by the Perseverance rover has identified three types of regolith: fine-grained, coarse-grained, and mixed-type. Mastcam-Z, WATSON, and SuperCam RMI were used to characterize regolith texture, particle size, and roundedness where possible. Mastcam-Z multispectral and SuperCam LIBS data were used to constrain the composition of the regolith types. Fine-grained regolith is found surrounding bedrock and boulders, comprising bedforms, and accumulating on top of rocks in erosional depressions. Spectral and chemical data show it is compositionally consistent with pyroxene and a ferric-oxide phase. Coarse-grained regolith consists of 1-2 mm well-sorted gray grains that are found concentrated around the base of boulders and bedrock, and armoring bedforms. Its chemistry and spectra indicate it is olivine-bearing, and spatial distribution and roundedness indicate it has been transported, likely by saltation-induced creep. Coarse grains share similarities with the olivine grains observed in the Séítah formation bedrock, making that unit a possible source for these grains. Mixed-type regolith contains fine- and coarse-grained regolith components and larger rock fragments. The rock fragments are texturally and spectrally similar to bedrock within the Máaz and Séítah formations, indicating origins by erosion from those units, although they could also be a lag deposit from erosion of an overlying unit. The fine- and coarse-grained types are compared to their counterparts at other landing sites to inform global, regional, and local inputs to regolith formation within Jezero crater. The regolith characterization presented here informs regolith sampling efforts underway by Perseverance.

Publication Year 2023
Title Regolith of the crater floor units, Jezero crater, Mars: Textures, composition and implications for provenance
DOI 10.1029/2022JE007437
Authors Alicia Vaughan, Michelle E. Minitti, Emily L. Cardarelli, Jeffrey R. Johnson, Linda C. Kah, Paolo Pilleri, Mellisa S. Rice, Mark Sephton, Briony H. N. Horgan, Roger C. Wiens, R. Aileen Yingst, Maria-Paz Zorzano Mier, Ryan Anderson, James F. III Bell, Adrian J. Brown, Edward A. Cloutis, Agnes Cousin, Kenneth E. Herkenhoff, Elisabeth M. Housrath, Alexander G. Hayes, Kjartan M. Kinch, Marco Merusi, Chase C. Million, Robert Sullivan, Sandra M. Siljestrom, Michael St. Clair
Publication Type Article
Publication Subtype Journal Article
Series Title JGR-Planets
Index ID 70240880
Record Source USGS Publications Warehouse
USGS Organization Astrogeology Science Center