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Spectral, Compositional, and Physical Properties of the Upper Murray Formation and Vera Rubin Ridge, Gale Crater, Mars

Jacob, S. R. and Wellington, D. F. and Bell, J. F., III and Achilles, C. and Fraeman, A. A. and Horgan, B. and Johnson, J. R. and Maurice, S. and Peters, G. H. and Rampe, E. B. and Thompson, L. M. and Wiens, R. C. (2020) Spectral, Compositional, and Physical Properties of the Upper Murray Formation and Vera Rubin Ridge, Gale Crater, Mars. Journal of Geophysical Research. Planets, 125 (11). Art. No. e2019JE006290. ISSN 2169-9097.

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During 2018 and 2019, the Mars Science Laboratory Curiosity rover investigated the chemistry, morphology, and stratigraphy of Vera Rubin ridge (VRR). Using orbital data from the Compact Reconnaissance Imaging Spectrometer for Mars, scientists attributed the strong 860 nm signal associated with VRR to the presence of red crystalline hematite. However, Mastcam multispectral data and CheMin X‐ray diffraction (XRD) measurements show that the depth of the 860 nm absorption is negatively correlated with the abundance of red crystalline hematite, suggesting that other mineralogical or physical parameters are also controlling the 860 nm absorption. Here, we examine Mastcam and ChemCam passive reflectance spectra from VRR and other locations to link the depth, position, and presence or absence of iron‐related mineralogic absorption features to the XRD‐derived rock mineralogy. Correlating CheMin mineralogy to spectral parameters showed that the ~860 nm absorption has a strong positive correlation with the abundance of ferric phyllosilicates. New laboratory reflectance measurements of powdered mineral mixtures can reproduce trends found in Gale crater. We hypothesize that variations in the 860 nm absorption feature in Mastcam and ChemCam observations of VRR materials are a result of three factors: (1) variations in ferric phyllosilicate abundance due to its ~800–1,000 nm absorption; (2) variations in clinopyroxene abundance because of its band maximum at ~860 nm; and (3) the presence of red crystalline hematite because of its absorption centered at 860 nm. We also show that relatively small changes in Ca‐sulfate abundance is one potential cause of the erosional resistance and geomorphic expression of VRR.

Item Type:Article
Related URLs:
URLURL TypeDescription
http://an.rsl.wustl.eduRelated ItemCuriosity data ItemMastcam images
Jacob, S. R.0000-0001-9950-1486
Wellington, D. F.0000-0002-2130-0075
Bell, J. F., III0000-0002-2006-4074
Achilles, C.0000-0001-9185-6768
Fraeman, A. A.0000-0003-4017-5158
Horgan, B.0000-0001-6314-9724
Johnson, J. R.0000-0002-5586-4901
Peters, G. H.0000-0003-1590-630X
Rampe, E. B.0000-0002-6999-0028
Thompson, L. M.0000-0002-5444-952X
Wiens, R. C.0000-0002-3409-7344
Additional Information:© 2020 The Authors. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. Issue Online: 03 November 2020; Version of Record online: 03 November 2020; Accepted manuscript online: 28 August 2020; Manuscript accepted: 21 August 2020; Manuscript revised: 20 August 2020; Manuscript received: 27 November 2019. We would like to thank the wonderfully talented engineers and scientists around the world who have made the MSL Curiosity mission such a success and who have helped to obtain and calibrate the data presented in this paper. Reviews by V. Fox and E. Amador were greatly appreciated and helped significantly improve this paper. This work was funded by the NASA Mars Science Laboratory Project via a subcontract to Arizona State University through Malin Space Science Systems, Inc. (J. R. J. supported by Mars Science Laboratory (MSL) Participating Scientist contract 1546033). A portion of this research was also carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the NASA. Data Availability Statement: The new laboratory data generated and used as part of this research are publicly available on the Zenodo open data depository (; Jacob, 2020). All Curiosity data can be accessed through the online Analyst's Notebook tool (, and Mastcam images are available online on the NASA Planetary Data System (https://pds‐
Funding AgencyGrant Number
Arizona State UniversityUNSPECIFIED
Malin Space Science Systems, Inc.UNSPECIFIED
Subject Keywords:Mastcam; Multispectral; Laboratory; Phyllosilicates; Hematite; Ferric Iron
Issue or Number:11
Record Number:CaltechAUTHORS:20200901-102620010
Persistent URL:
Official Citation:Jacob, S. R., Wellington, D. F., Bell, J. F., Achilles, C., Fraeman, A. A., Horgan, B., et al. (2020). Spectral, compositional, and physical properties of the Upper Murray formation and Vera Rubin ridge, Gale crater, Mars. Journal of Geophysical Research: Planets, 125, e2019JE006290.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105199
Deposited By: Tony Diaz
Deposited On:08 Sep 2020 19:57
Last Modified:06 Nov 2020 17:13

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