Visible/near-infrared spectral diversity from in situ observations of the Bagnold Dune Field sands in Gale Crater, Mars
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Author
Johnson, Jeffrey R.
Achilles, Cherie

Bell, James F.

Bender, Steve
Cloutis, E. A.

Ehlmann, Bethany

Fraeman, Abigail

Gasnault, Olivier

Hamilton, Victoria E.

Le Mouélic, Stéphane
Maurice, Sylvestre
Pinet, Patrick

Thompson, Lucy

Wellington, Danika
Wiens, Roger C.
Affiliation
Univ Arizona, Dept GeosciIssue Date
2017-12
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AMER GEOPHYSICAL UNIONCitation
Visible/near-infrared spectral diversity from in situ observations of the Bagnold Dune Field sands in Gale Crater, Mars 2017, 122 (12):2655 Journal of Geophysical Research: PlanetsRights
© 2017. American Geophysical Union. All Rights Reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
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 (445-1013nm) and Chemistry and Camera (ChemCam) passive point spectroscopy (400-840nm). 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 similar to 530nm absorption band, an absorption band near 620nm, and a spectral downturn after similar to 685nm consistent with olivine-bearing sands. The finest grain size fractions occurred within ripple troughs and in the subsurface and typically exhibited the strongest similar to 530nm 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 similar to 530nm 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.Note
6 month embargo; published online: 13 December 2017ISSN
21699097Version
Final published versionSponsors
NASA Mars Science Laboratory Participating Scientist program through the Jet Propulsion Laboratory [1350588, 1449892, 1546033]; Centre National d'Etudes Spatiales (CNES); NSERC; CSA; CFI; MRIFAdditional Links
http://doi.wiley.com/10.1002/2016JE005187ae974a485f413a2113503eed53cd6c53
10.1002/2016JE005187