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Published December 16, 2018 | Supplemental Material + Published
Journal Article Open

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

Abstract

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.

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, www.pds.nasa.gov.

Attached Files

Published - Gabriel_et_al-2018-Geophysical_Research_Letters.pdf

Supplemental Material - grl57969-sup-0001-supplementary.pdf

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