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Title: Geochemistry of the Bagnold dune field as observed by ChemCam and comparison with other aeolian deposits at Gale Crater

The Curiosity rover conducted the first field investigation of an active extraterrestrial dune. Our study of the Bagnold dunes focuses on the ChemCam chemical results and also presents findings on the grain size distributions based on the ChemCam RMI and MAHLI images. These active dunes are composed of grains that are mostly <250 μm. Their composition is overall similar to that of the aeolian deposits analyzed all along the traverse (“Aeolis Palus soils”). Nevertheless, the dunes contain less volatiles (Cl, H, S) than the Aeolis Palus soils, which appears to be due to a lower content of volatile-rich fine-grained particles (<100 μm), or a lower content of volatile-rich amorphous component, possibly as a result of: 1) a lower level of chemical alteration; 2) the removal of an alteration rind at the surface of the grains during transport; 3) a lower degree of interaction with volcanic gases/aerosols; or 4) physical sorting that removed the smallest and most altered grains. Analyses of the >150 μm grain-size dump piles have shown that coarser grains (150-250 μm) are enriched in the mafic elements Fe and Mn, suggesting a larger content in olivine compared to smaller grains (<150 μm) of the Bagnold dunes. Furthermore, themore » chemistry of soils analyzed in the vicinity of the dunes indicates that they are similar to the dune material. Altogether these observations suggest that the olivine content determined by X-ray diffraction of the <150 μm grain-size sample should be considered as a lower limit for the Bagnold dunes.« less
Authors:
 [1] ; ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [1] ; ORCiD logo [4] ; ORCiD logo [3] ; ORCiD logo [5] ; ORCiD logo [6] ;  [1] ;  [1] ; ORCiD logo [7] ; ORCiD logo [8] ; ORCiD logo [1] ;  [1] ; ORCiD logo [8]
  1. Univ. of Toulouse (France). Inst. for Research in Astrophysics and Planetology (IRAP)
  2. Towson Univ., MD (United States). Dept. of Physics Astronomy and Geosciences
  3. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  4. Applied Physics Lab., Laurel, MD (United States)
  5. German Aerospace Center (DLR), Berlin (Germany)
  6. Univ. of Loraine, Nancy (France)
  7. National Museum of Natural History, Paris (France)
  8. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-17-27677
Journal ID: ISSN 2169-9097
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Planets
Additional Journal Information:
Journal Volume: 122; Journal Issue: 10; Journal ID: ISSN 2169-9097
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; National Aeronautics and Space Administration (NASA)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Planetary Sciences
OSTI Identifier:
1396139