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Title: Shaler: in situ analysis of a fluvial sedimentary deposit on Mars

This article characterizes the detailed sedimentology of a fluvial sandbody on Mars for the first time and interprets its depositional processes and palaeoenvironmental setting. Despite numerous orbital observations of fluvial landforms on the surface of Mars, ground-based characterization of the sedimentology of such fluvial deposits has not previously been possible. Results from the NASA Mars Science Laboratory Curiosity rover provide an opportunity to reconstruct at fine scale the sedimentary architecture and palaeomorphology of a fluvial environment on Mars. This work describes the grain size, texture and sedimentary facies of the Shaler outcrop, reconstructs the bedding architecture, and analyses cross-stratification to determine palaeocurrents. On the basis of bedset geometry and inclination, grain-size distribution and bedform migration direction, this study concludes that the Shaler outcrop probably records the accretion of a fluvial barform. The majority of the outcrop consists of large-scale trough cross-bedding of coarse sand and granules. Palaeocurrent analyses and bedform reconstruction indicate that the beds were deposited by bedforms that migrated towards the north-east, across the surface of a bar that migrated south-east. Stacked cosets of dune cross-bedding suggest aggradation of multiple bedforms, which provides evidence for short periods of sustained flow during Shaler deposition. However, local evidence for aeolianmore » reworking and the presence of potential desiccation cracks within the outcrop suggest that fluvial deposition may have been intermittent. The uppermost strata at Shaler are distinct in terms of texture and chemistry and are inferred to record deposition from a different sediment dispersal system with a contrasting provenance. The outcrop as a whole is a testament to the availability of liquid water on the surface of Mars in its early history.« less
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [6] ;  [7] ;  [8] ;  [9] ;  [6] ;  [10] ;  [11] ;  [8] ;  [12] ;  [13] ;  [14] ;  [9] ;  [15] ;  [16] more »;  [17] ;  [18] ;  [19] ; ORCiD logo [20] ;  [14] ; ORCiD logo [21] « less
  1. U.S. Geological Survey, Flagstaff, AZ (United States). Astrogeology Science Center
  2. Imperial College, London (United Kingdom). Dept. of Earth Science and Engineering
  3. Univ. of California, Santa Cruz, CA (United States). Dept. of Earth & Planetary Sciences
  4. Johns Hopkins Univ., Baltimore, MD (United States). Department of Earth and Planetary Sciences
  5. Univ. of Texas, Austin, TX (United States). Jackson School of Geosciences, Dept. of Geological Sciences
  6. Arizona State Univ., Tempe, AZ (United States). School of Earth and Space Exploration
  7. Univ. de Lyon, Lyon (France). Lab. de Geologie de Lyon
  8. Malin Space Science Systems, San Diego, CA (United States)
  9. California Inst. of Technology (CalTech), Pasadena, CA (United States). Division of Geological and Planetary Sciences
  10. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Earth and Planetary Sciences
  11. McGill Univ., Montreal, QC (Canada). Dept. of Earth & Planetary Sciences
  12. Univ. de Nantes, Nantes (France). Laboratoire de Planetologie et Geodynamique
  13. Brown Univ., Providence, RI (United States). Dept. of Geological Sciences
  14. Planetary Science Inst., Tucson, AZ (United States)
  15. Western Washington Univ., Bellingham, WA (United States). College of Science and Engineering
  16. Univ. of Hawaii at Manoa, Honolulu, HI (United States). School of Ocean and Earth Science and Technology
  17. Indiana Univ., Bloomington, IN (United States). Dept. of Geological Sciences
  18. California Inst. of Technology (CalTech), La Canada Flintridge, CA (United States). Jet Propulsion Lab.
  19. Univ. of California, Davis, CA (United States). Earth and Planetary Sciences
  20. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  21. Towson Univ., Towson, MD (United States). Dept. of Physics, Astronomy and Geosciences
Publication Date:
Report Number(s):
Journal ID: ISSN 0037-0746
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 65; Journal Issue: 1; Journal ID: ISSN 0037-0746
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
National Aeronautic and Space Administration (NASA); USDOE; UK Space Agency (UKSA); Science and Technology Funding Council (STFC)
Country of Publication:
United States
58 GEOSCIENCES; Planetary Sciences
OSTI Identifier: