Published December 1, 2025 | Version Published
Journal Article Open

Alteration history of aluminum-rich rocks at Jezero crater, Mars

  • 1. ROR icon Purdue University West Lafayette
  • 2. ROR icon University of Oregon
  • 3. ROR icon Atmospheres Laboratory Environments, Observations Spatiales
  • 4. ROR icon University of California, Los Angeles
  • 5. ROR icon University of the Basque Country
  • 6. ROR icon Grenoble Alpes University
  • 7. ROR icon California Institute of Technology
  • 8. ROR icon Jet Propulsion Lab
  • 9. ROR icon Dartmouth College
  • 10. ROR icon Paul Sabatier University
  • 11. ROR icon Institut d'Astrophysique Spatiale
  • 12. ROR icon Claude Bernard University Lyon 1
  • 13. ROR icon Johns Hopkins University Applied Physics Laboratory
  • 14. University of Nevada, Las Vegas (UNLV), Las Vegas, NV, USA
  • 15. ROR icon Los Alamos National Laboratory
  • 16. ROR icon University of Winnipeg
  • 17. ROR icon Arizona State University
  • 18. ROR icon Johnson Space Center
  • 19. ROR icon Research Institute in Astrophysics and Planetology

Abstract

Aluminum-rich clay minerals are detected across the ancient surface of Mars and record intervals of intense alteration by liquid water. On Earth, these clay minerals can form from hydrothermal alteration or rainfall-driven chemical weathering over thousands to millions of years, but how they formed on Mars remains a mystery. The Perseverance rover discovered light-toned, cobble-sized, aluminum-rich (30-45 wt% Al2O3) “float” rocks (rock fragments), with some exhibiting spectral signatures of kaolinite, an aluminum-rich clay mineral. These rocks now enable an investigation into the ancient kaolinite-bearing terrains of Mars. To interpret their formation, we use data from the SuperCam and Mastcam-Z instruments onboard the rover to compare the chemistry and reflectance spectra of the float rocks with deeply weathered paleosols and hydrothermal kaolin deposits from Earth’s geological record. Aluminum and titanium enrichments coupled with depletion of iron and magnesium are unlike hydrothermal deposits and instead comparable to bleached horizons of paleosols that formed under high rainfall during past greenhouse climates on Earth. These rocks therefore likely represent some of the wettest intervals of Mars’ history.

Copyright and License

© The Author(s) 2025. This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.

Acknowledgement

The authors are eternally grateful for the Mars 2020 Science and Engineering Teams, and the decades of authors who have studied Earth’s kaolinite. Funding sources: NASA contract NNH13ZDA018O for SuperCam (C.R., C.C.B., R.C.W., A.O., S.C.); SuperCam, (1532432) and Mastcam-Z (15-707, 1511125) (JRJ); Mastcam-Z (15-707, 1511125) (BK); Texaco Postdoctoral prize fellowship awarded by the division of Geological and Planetary Sciences of Caltech (L.M.); Spanish Agency for Research AEI/MCIN/FEDER, Grant No. PID2022-142750OB-I00 (J.M.M.), and NASA RSS Participating Scientist grant 80NSSC20K0239 (E.M.H.). A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004).

Data Availability

The supplementary dataset (Supplementary Data) containing elemental composition and reflectance spectra of all targets examined in this work is available at https://doi.org/10.5281/zenodo.17109674. All Mars 2020 Perseverance rover datasets (including those used in this work) are available on the Planetary Data System (PDS) at the PDS Geosciences Node (https://pds-geosciences.wustl.edu/missions/mars2020/index.html) and the PDS Cartography and Imaging Sciences Node (https://pds-imaging.jpl.nasa.gov/volumes/mars2020.html). Links to specific instrument dataset bundles are listed below:

Mars 2020 Mission bundle: https://doi.org/10.17189/1522642

SuperCam Instrument bundle: https://doi.org/10.17189/1522646

Mastcam-Z Science Imaging bundle: https://doi.org/10.17189/q3ts-c749

Supplemental Material

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Additional details

Identifiers

Funding

National Aeronautics and Space Administration
NNH13ZDA018O
National Aeronautics and Space Administration
1532432
National Aeronautics and Space Administration
1511125
California Institute of Technology
Texaco Postdoctoral Prize Fellowship -
Ministerio de Ciencia, Innovación y Universidades
PID2022-142750OB-I00
National Aeronautics and Space Administration
80NSSC20K0239
Jet Propulsion Laboratory
National Aeronautics and Space Administration
80NM0018D0004

Dates

Submitted
2025-05-21
Accepted
2025-09-30

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