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Water Abundance of Dunes in Gale Crater, Mars From Active Neutron Experiments and Implications for Amorphous Phases

Gabriel, T. S. J. and Hardgrove, C. and Czarnecki, S. and Rampe, E. B. and Rapin, W. and Achilles, C. N. and Sullivan, D. and Nowicki, S. and Thompson, L. and Litvak, M. and Mitrofanov, I. and Downs, R. T. (2018) Water Abundance of Dunes in Gale Crater, Mars From Active Neutron Experiments and Implications for Amorphous Phases. Geophysical Research Letters, 45 (23). pp. 12766-12775. ISSN 0094-8276.

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We report the water abundance of Bagnold Dune sand in Gale crater, Mars by analyzing active neutron experiments using the Dynamic Albedo of Neutrons instrument. We report a bulk water‐equivalent‐hydrogen abundance of 0.68 ± 0.15 wt%, which is similar to measurements several kilometers away and from those taken of the dune surface. Thus, the dune is likely dehydrated throughout. Furthermore, we use geochemical constraints, including bulk water content, to develop compositional models of the amorphous fraction for which little information is known. We find the amorphous fraction contains ∼26‐ to 64‐wt% basaltic glass and up to ∼24‐wt% rhyolitic glass, suggesting at least one volcanic source for the dune material. We also find a range of hydrated phases may be present in appreciable abundances, either from the incorporation of eroded aqueously altered sediments or the direct alteration of the dune sand.

Item Type:Article
Related URLs:
URLURL TypeDescription
Gabriel, T. S. J.0000-0002-9767-4153
Hardgrove, C.0000-0002-8556-6630
Czarnecki, S.0000-0002-4300-4066
Rampe, E. B.0000-0002-6999-0028
Rapin, W.0000-0003-4660-8006
Achilles, C. N.0000-0001-9185-6768
Sullivan, D.0000-0002-1336-0940
Nowicki, S.0000-0003-1140-6703
Thompson, L.0000-0002-5444-952X
Downs, R. T.0000-0002-8380-7728
Additional Information:© 2018 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. Received 1 JUN 2018; Accepted 27 AUG 2018; Accepted article online 4 SEP 2018; Published online 11 DEC 2018. We acknowledge the Dynamic Albedo of Neutrons instrument team and the broader Mars Science Laboratory team. This work was supported by the Mars Science Laboratory Participating Scientist Program, award number NNN12AA01C, and by the NASA Earth and Space Science Fellowship, award PLANET17F‐0107. Computational support was provided in part by the Space Science and Applications group at Los Alamos National Laboratory and by the Research Computing center at Arizona State University. The authors thank Michael Line at Arizona State University for providing insight into statistical methods used herein and the authors thank Jack Lightholder at Jet Propulsion Laboratory for his early contributions to the project. All data from this work are publicly accessible on the Planetary Data System,
Funding AgencyGrant Number
NASA Earth and Space Science FellowshipPLANET17F‐0107
Subject Keywords:neutron spectroscopy; Mars; water; amorphous; DAN; Curiosity rover
Issue or Number:23
Record Number:CaltechAUTHORS:20190109-151441597
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Official Citation:Gabriel, T. S. J., Hardgrove, C., Czarnecki, S., Rampe, E. B., Rapin, W., Achilles, C. N., et al. (2018). Water abundance of dunes in Gale crater, Mars from active neutron experiments and implications for amorphous phases. Geophysical Research Letters, 45, 12,766–12,775.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92180
Deposited By: Tony Diaz
Deposited On:10 Jan 2019 12:27
Last Modified:03 Oct 2019 20:42

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