Volume 128, Issue 10 e2022JE007433
Research Article

An Examination of Soil Crusts on the Floor of Jezero Crater, Mars

E. M. Hausrath

Corresponding Author

E. M. Hausrath

Department of Geoscience, University of Nevada, Las Vegas, NV, USA

Correspondence to:

E. M. Hausrath,

[email protected]

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C. T. Adcock

C. T. Adcock

Department of Geoscience, University of Nevada, Las Vegas, NV, USA

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A. Bechtold

A. Bechtold

Department of Lithospheric Research, University of Vienna, Vienna, Austria

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P. Beck

P. Beck

University of Grenoble Alpes, CNRS, IPAG, Grenoble, France

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K. Benison

K. Benison

Department of Geology and Geography, West Virginia University, Morgantown, WV, USA

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A. Brown

A. Brown

Plancius Research, Severna Park, MD, USA

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E. L. Cardarelli

E. L. Cardarelli

Jet Propulsion Laboratory, California Institute of Technology, CA, Pasadena, USA

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N. A. Carman

N. A. Carman

Department of Geoscience, University of Nevada, Las Vegas, NV, USA

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B. Chide

B. Chide

Los Alamos National Laboratory, Los Alamos, NM, USA

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J. Christian

J. Christian

Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA

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B. C. Clark

B. C. Clark

Space Science Institute, Boulder, CO, USA

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E. Cloutis

E. Cloutis

Department of Geography, University of Winnipeg, Winnipeg, MB, Canada

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A. Cousin

A. Cousin

Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse 3 Paul Sabatier, CNRS, CNES, Toulouse, France

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O. Forni

O. Forni

Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse 3 Paul Sabatier, CNRS, CNES, Toulouse, France

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T. S. J. Gabriel

T. S. J. Gabriel

US Geological Survey, Flagstaff, AZ, USA

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O. Gasnault

O. Gasnault

Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse 3 Paul Sabatier, CNRS, CNES, Toulouse, France

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M. Golombek

M. Golombek

Jet Propulsion Laboratory, California Institute of Technology, CA, Pasadena, USA

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F. Gómez

F. Gómez

Centro de Astrobiologia (CSIC-INTA), Madrid, Spain

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M. H. Hecht

M. H. Hecht

Haystack Observatory, Massachusetts Institute of Technology, Westford, MA, USA

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T. L. J. Henley

T. L. J. Henley

Department of Earth Science, Brock University, St. Catharines, ON, Canada

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J. Huidobro

J. Huidobro

Department of Analytical Chemistry, University of the Basque Country UPV/EHU, Leioa, Spain

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J. Johnson

J. Johnson

John Hopkins University Applied Physics Laboratory, Laurel, MD, USA

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M. W. M. Jones

M. W. M. Jones

Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, Australia

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P. Kelemen

P. Kelemen

Columbia University, New York City, NY, USA

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A. Knight

A. Knight

Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA

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J. A. Lasue

J. A. Lasue

Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse 3 Paul Sabatier, CNRS, CNES, Toulouse, France

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S. Le Mouélic

S. Le Mouélic

Laboratoire de Planétologie et Géosciences, CNRS, UMR 6112, Nantes Université, University Angers, Nantes, France

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J. M. Madariaga

J. M. Madariaga

Department of Analytical Chemistry, University of the Basque Country UPV/EHU, Leioa, Spain

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J. Maki

J. Maki

Jet Propulsion Laboratory, California Institute of Technology, CA, Pasadena, USA

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L. Mandon

L. Mandon

LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, Meudon, France

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G. Martinez

G. Martinez

Lunar and Planetary Institute, Houston, TX, USA

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J. Martínez-Frías

J. Martínez-Frías

Instituto de Geociencias, Madrid, Spain

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T. H. McConnochie

T. H. McConnochie

Space Science Institute, Boulder, CO, USA

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P.-Y. Meslin

P.-Y. Meslin

Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse 3 Paul Sabatier, CNRS, CNES, Toulouse, France

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M.-P. Zorzano

M.-P. Zorzano

Centro de Astrobiologia (CSIC-INTA), Madrid, Spain

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H. Newsom

H. Newsom

University of New Mexico, Albuquerque, NM, USA

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G. PaarN. Randazzo

N. Randazzo

Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada

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C. Royer

C. Royer

Observatoire de Paris, LESIA, CNRS, Université PSL, Sorbonne Université, Université de Paris, Meudon, France

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S. Siljeström

S. Siljeström

RISE Research Institutes of Sweden, Stockholm, Sweden

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M. E. Schmidt

M. E. Schmidt

Department of Earth Science, Brock University, St. Catharines, ON, Canada

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S. Schröder

S. Schröder

Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institute of Optical Sensor Systems (OS), Berlin, Germany

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M. A. Sephton

M. A. Sephton

Department of Earth Science & Engineering, Imperial College, London, UK

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R. Sullivan

R. Sullivan

CCAPS, Cornell University, Ithaca, NY, USA

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N. Turenne

N. Turenne

Department of Geography, University of Winnipeg, Winnipeg, MB, Canada

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A. Udry

A. Udry

Department of Geoscience, University of Nevada, Las Vegas, NV, USA

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S. VanBommel

S. VanBommel

Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA

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A. Vaughan

A. Vaughan

Apogee Engineering, LLC, Flagstaff, AZ, USA

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R. C. Wiens

R. C. Wiens

Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, USA

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N. Williams

N. Williams

Jet Propulsion Laboratory, California Institute of Technology, CA, Pasadena, USA

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the SuperCam team and the Regolith working group

the SuperCam team and the Regolith working group

See Table S4 and S5

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First published: 21 February 2023
Citations: 4

Abstract

Martian soils are critically important for understanding the history of Mars, past potentially habitable environments, returned samples, and future human exploration. This study examines soil crusts on the floor of Jezero crater encountered during initial phases of the Mars 2020 mission. Soil surface crusts have been observed on Mars at other locations, starting with the two Viking Lander missions. Rover observations show that soil crusts are also common across the floor of Jezero crater, revealed in 45 of 101 locations where rover wheels disturbed the soil surface, two out of seven helicopter flights that crossed the wheel tracks, and four of eight abrasion/drilling sites. Most soils measured by the SuperCam laser-induced breakdown spectroscopy (LIBS) instrument show high hydrogen content at the surface, and fine-grained soils also show a visible/near infrared (VISIR) 1.9 μm H2O absorption feature. The Planetary Instrument for X-ray Lithochemistry (PIXL) and SuperCam observations suggest the presence of salts at the surface of rocks and soils. The correlation of S and Cl contents with H contents in SuperCam LIBS measurements suggests that the salts present are likely hydrated. On the “Naltsos” target, magnesium and sulfur are correlated in PIXL measurements, and Mg is tightly correlated with H at the SuperCam points, suggesting hydrated Mg-sulfates. Mars Environmental Dynamics Analyzer (MEDA) observations indicate possible frost events and potential changes in the hydration of Mg-sulfate salts. Jezero crater soil crusts may therefore form by salts that are hydrated by changes in relative humidity and frost events, cementing the soil surface together.

Key Points

  • Soil crusts are prevalent across the Jezero crater floor

  • Soil surfaces are largely hydrated

  • Soil crusts likely contain salts and may form during changes in atmospheric relative humidity at the surface

Plain Language Summary

Martian soils are important for understanding the history of Mars as well as future sample return and human exploration. Soil crusts in Jezero crater, which are also broadly found across Mars, can be observed when they are disturbed, such as by rover wheels or coring/abrasion activities. Jezero crater soil crusts are examined using images from the Perseverance and Ingenuity cameras, as well as using data from the SuperCam, PIXL, Mastcam-Z, and MEDA instruments. Soil crusts are common in Jezero crater and show characteristics including hydration at the surface and the presence of salts that might contain water. MEDA instrument measurements indicate that changes in the hydration state of salts may result during conditions measured at Jezero crater. Jezero crater soil crusts may therefore form by salts that are present on the surface that can add or lose water during changes in relative atmospheric humidity and frost events. These changes in the amount of water present in the salts may result in soil surfaces that are cemented together, forming the crusts observed at Jezero crater. A better understanding of Mars soil crusts will help in the understanding of samples returned to Earth from Mars, as well as future human exploration.

Conflict of Interest

The authors declare no conflicts of interest relevant to this study.

Data Availability Statement

The data in this publication are from the SuperCam, PIXL, Mastcam-Z, MEDA, and Watson instruments, and the Navcam and Hazcam cameras of the Mars 2020 Perseverance rover. The SuperCam data include the Laser Induced Breakdown Spectroscopy (LIBS), Visible/near infrared (VISIR) Spectroscopy, and the Remote Microimager images. The PIXL data include images, PIXL spectra, and oxide concentrations. The Mastcam-Z data include the stereo images, and the results of the 3-D processing presented in Paar et al. (2023). The Hazcam and Navcam data include the images, and the MEDA data include ground temperature, relative humidity, and images. The SuperCam Major-element Oxide Composition (MOC), total emissivity, and all raw data and processed calibrated data files are included in the Planetary Data System (Wiens, Maurice, Deen, et al., 2021). The SuperCam H scores are generated after Forni et al. (2013), and the retrieved H component used to tabulate the H scores after Forni et al. (2013) is included in Figure S7 of Supporting Information S1 and Table S1. The Cl and S scores are generated after Meslin et al. (2023), and displayed in that manuscript. The PIXL images and spectra are in the PDS (Allwood & Hurowitz, 2021), and the oxide concentrations are in the supplemental online material (Table S3 in Supporting Information S1). The Mastcam-Z data for all images used in this manuscript are available in the PDS (Bell et al., 2021, https://doi.org/10.17189/BS6B-4782). All Mars 2020 MEDA data necessary to reproduce each figure shown in this manuscript are available via the Planetary Data System (PDS) Atmospheres node (Rodriguez-Manfredi & de la Torre Juarez, 2021). The Navcam (Maki et al., 2020b), Hazcam (Maki et al., 2020a, https://doi.org/10.17189/282b-1524) helicopter (Balaram et al., 2021) and Watson images (Beegle et al., 2021) are available in the PDS. Microphone data are available on the Planetary Data System (Wiens, Maurice, Deen, et al., 2021). The data for comparison from the Mars Exploration Rover mission used in Figure S2 in Supporting Information S1 are available on the PDS for that mission here: https://pds-geosciences.wustl.edu/missions/mer/mer_apxs_oxide.htm.