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Visible/near-infrared spectral diversity from in situ observations of the Bagnold Dune Field sands in Gale Crater, Mars

Johnson, Jeffrey R. and Achilles, Cherie and Bell, James F., III and Bender, Steve and Cloutis, Edward and Ehlmann, Bethany and Fraeman, Abigail and Gasnault, Olivier and Hamilton, Victoria E. and Le Mouélic, Stéphane and Maurice, Sylvestre and Pinet, Patrick and Thompson, Lucy and Wellington, Danika and Wiens, Roger C. (2017) Visible/near-infrared spectral diversity from in situ observations of the Bagnold Dune Field sands in Gale Crater, Mars. Journal of Geophysical Research. Planets, 122 (12). pp. 2655-2684. ISSN 2169-9097. doi:10.1002/2016JE005187.

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As part of the Bagnold Dune campaign conducted by Mars Science Laboratory rover Curiosity, visible/near-infrared reflectance spectra of dune sands were acquired using Mast Camera (Mastcam) multispectral imaging (445–1013 nm) and Chemistry and Camera (ChemCam) passive point spectroscopy (400–840 nm). By comparing spectra from pristine and rover-disturbed ripple crests and troughs within the dune field, and through analysis of sieved grain size fractions, constraints on mineral segregation from grain sorting could be determined. In general, the dune areas exhibited low relative reflectance, a weak ~530 nm absorption band, an absorption band near 620 nm, and a spectral downturn after ~685 nm consistent with olivine-bearing sands. The finest grain size fractions occurred within ripple troughs and in the subsurface and typically exhibited the strongest ~530 nm bands, highest relative reflectances, and weakest red/near-infrared ratios, consistent with a combination of crystalline and amorphous ferric materials. Coarser-grained samples were the darkest and bluest and exhibited weaker ~530 nm bands, lower relative reflectances, and stronger downturns in the near-infrared, consistent with greater proportions of mafic minerals such as olivine and pyroxene. These grains were typically segregated along ripple crests and among the upper surfaces of grain flows in disturbed sands. Sieved dune sands exhibited progressive decreases in reflectance with increasing grain size, as observed in laboratory spectra of olivine size separates. The continuum of spectral features observed between the coarse- and fine-grained dune sands suggests that mafic grains, ferric materials, and air fall dust mix in variable proportions depending on aeolian activity and grain sorting.

Item Type:Article
Related URLs:
URLURL TypeDescription
Johnson, Jeffrey R.0000-0002-5586-4901
Achilles, Cherie0000-0001-9185-6768
Bell, James F., III0000-0002-2006-4074
Cloutis, Edward0000-0001-7301-0929
Ehlmann, Bethany0000-0002-2745-3240
Fraeman, Abigail0000-0003-4017-5158
Gasnault, Olivier0000-0002-6979-9012
Hamilton, Victoria E.0000-0001-8675-2083
Pinet, Patrick0000-0002-1933-5631
Thompson, Lucy0000-0002-5444-952X
Wiens, Roger C.0000-0002-3409-7344
Additional Information:© 2017 American Geophysical Union. Received 3 OCT 2016; Accepted 10 JAN 2017; Published online 13 DEC 2017. This work was funded by the NASA Mars Science Laboratory Participating Scientist program through the Jet Propulsion Laboratory (contracts 1350588, 1449892, and 1546033). 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. The U.S. portion of ChemCam and MSL rover operations was funded by NASA's Mars Exploration Program. The French contribution to MSL is supported by the Centre National d'Etudes Spatiales (CNES). The authors thank Ray Arvidson (Washington University in St. Louis) for providing the CRISM spectrum of Namib Dune and Daniel Applin (University of Winnipeg) for spectra of sieved San Carlos samples. The authors thank the operations teams involved in acquiring these data sets, including the dedicated efforts of the payload uplink leads for the Mastcam and ChemCam teams. E.A.C. thanks NSERC, CSA, CFI, and MRIF for supporting the UW Planetary Spectrophotometer Facility at UW. Detailed reviews by D. Rogers and an anonymous reviewer helped clarify the presentation and analytical details of the manuscript. Original data that underlie the conclusions presented in this manuscript can be found on the NASA Planetary Data System and/or in the relevant references cited.
Group:Astronomy Department
Funding AgencyGrant Number
Mars Science Laboratory (MSL)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Subject Keywords:Curiosity; Bagnold Dune; ChemCam; Mastcam; multispectral; visible spectroscopy
Issue or Number:12
Record Number:CaltechAUTHORS:20170425-140626753
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Official Citation:Johnson, J. R., et al. (2017), Visible/near-infrared spectral diversity from in situ observations of the Bagnold Dune Field sands in Gale Crater, Mars, J. Geophys. Res. Planets, 122, 2655–2684, doi:10.1002/2016JE005187
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76915
Deposited By: Tony Diaz
Deposited On:02 May 2017 17:52
Last Modified:15 Nov 2021 17:03

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