Diagenesis of Vera Rubin Ridge, Gale Crater, Mars, From Mastcam Multispectral Images
- Creators
- Horgan, Briony H. N.
- Johnson, Jeffrey R.
- Fraeman, Abigail A.
- Rice, Melissa S.
- Seeger, Christina
- Bell, James F., III
- Bennett, Kristen A.
- Cloutis, Edward A.
- Edgar, Lauren A.
- Frydenvang, Jens
- Grotzinger, John P.
- L'Haridon, Jonas
- Jacob, Samantha R.
- Mangold, Nicolas
- Rampe, Elizabeth B.
- Rivera‐Hernandez, Frances
- Sun, Vivian Z.
- Thompson, Lucy M.
- Wellington, Danika
Abstract
Images from the Mars Science Laboratory (MSL) mission of lacustrine sedimentary rocks of Vera Rubin ridge on "Mt. Sharp" in Gale crater, Mars, have shown stark color variations from red to purple to gray. These color differences crosscut stratigraphy and are likely due to diagenetic alteration of the sediments after deposition. However, the chemistry and timing of these fluid interactions is unclear. Determining how diagenetic processes may have modified chemical and mineralogical signatures of ancient Martian environments is critical for understanding the past habitability of Mars and achieving the goals of the MSL mission. Here we use visible/near‐infrared spectra from Mastcam and ChemCam to determine the mineralogical origins of color variations in the ridge. Color variations are consistent with changes in spectral properties related to the crystallinity, grain size, and texture of hematite. Coarse‐grained gray hematite spectrally dominates in the gray patches and is present in the purple areas, while nanophase and fine‐grained red crystalline hematite are present and spectrally dominate in the red and purple areas. We hypothesize that these differences were caused by grain‐size coarsening of hematite by diagenetic fluids, as observed in terrestrial analogs. In this model, early primary reddening by oxidizing fluids near the surface was followed during or after burial by bleaching to form the gray patches, possibly with limited secondary reddening after exhumation. Diagenetic alteration may have diminished the preservation of biosignatures and changed the composition of the sediments, making it more difficult to interpret how conditions evolved in the paleolake over time.
Additional Information
© 2020 American Geophysical Union. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. Issue Online: 31 October 2020; Version of Record online: 31 October 2020; Accepted manuscript online: 23 September 2020; Manuscript accepted: 19 September 2020; Manuscript revised: 03 September 2020; Manuscript received: 10 December 2019. We thank the MSL mission team for persevering through the challenges of exploration and collecting the data that enabled this work. We also thank Javier Cuadros, Ken Herkenhoff, and an anonymous reviewer for reviews that substantially improved the clarity of the manuscript and Sally Potter‐McIntyre and Ken Ridgway for useful discussions regarding diagenesis. Funding for this study was provided by the National Aeronautics and Space Administration (NASA) Mars Science Laboratory Participating Scientist program and the MSL mission. A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the NASA. J. F. acknowledges the Carlsberg Foundation (Carlsbergfondet). Data Availability Statement: All of the Mastcam images used in this manuscript are freely available through the Planetary Data System Cartography and Imaging Sciences node (https://pds‐imaging.jpl.nasa.gov/volumes/msl.html), as are all HiRISE images used in this manuscript (https://pds‐imaging.jpl.nasa.gov/volumes/mro.html). All of the ChemCam spectra used in this manuscript are freely available through the Planetary Data System Geosciences node (https://pds‐geosciences.wustl.edu/missions/msl/chemcam.htm). All Mastcam and ChemCam spectra shown in the manuscript and all calculated spectral parameters are available on Mendeley (https://doi.org/10.17632/w367ty5dr8.1).Attached Files
Published - 2019JE006322.pdf
Submitted - essoar105013802.pdf
Supplemental Material - jgre21485-sup-0001-text_si-s01.pdf
Supplemental Material - jgre21485-sup-0002-table_si-s01.xlsx
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Additional details
- Eprint ID
- 105573
- DOI
- 10.1029/2019je006322
- Resolver ID
- CaltechAUTHORS:20200925-135426875
- NASA/JPL/Caltech
- Carlsberg Foundation
- Created
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2020-09-25Created from EPrint's datestamp field
- Updated
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2023-10-02Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences