@article{c0380ac191e3498d9910fd8ca694a3a3,
title = "Identification and Description of a Silicic Volcaniclastic Layer in Gale Crater, Mars, Using Active Neutron Interrogation",
abstract = "The Dynamic Albedo of Neutrons instrument aboard the Mars Science Laboratory rover, Curiosity, has been used to map a stratigraphically conformable layer of high-SiO (Formula presented.) material in Gale crater. Previous work has shown that this material contains tridymite, a high-temperature/low-pressure felsic mineral, interpreted to have a volcanic source rock. We describe several characteristics including orientation, extent, hydration, and geochemistry, consistent with a volcaniclastic material conformably deposited within a lacustrine mudstone succession. Relationships with widely dispersed alteration features and orbital detections of hydrated SiO (Formula presented.) suggest that this high-SiO (Formula presented.) layer extends at least 17 km laterally. Mineralogical abundances previously reported for this high-SiO (Formula presented.) material indicated that hydrous species were restricted to the amorphous (non-crystalline) fraction, which is dominated by SiO (Formula presented.). The low mean bulk hydration of this high-SiO (Formula presented.) layer (1.85 (Formula presented.) 0.13 wt.% water-equivalent hydrogen) is consistent with silicic glass in addition to opal-A and opal-CT. Persistent volcanic glass and tridymite in addition to opal in an ancient sedimentary unit indicates that the conversion to more ordered forms of crystalline SiO (Formula presented.) has not proceeded to completion and that this material has had only limited exposure to water since it originally erupted, despite having been transported in a fluviolacustrine system. Our results, including the conformable nature, large areal extent, and presence of volcanic glass, indicate that this high-SiO (Formula presented.) material is derived from the product of evolved magma on Mars. This is the first identification of a silicic volcaniclastic layer on another planet and has important implications for magma evolution mechanisms on single-plate planets.",
keywords = "Gale crater, Marias Pass, Mars water, evolved igneous lithology, neutron spectroscopy, silica",
author = "S. Czarnecki and C. Hardgrove and Gasda, {P. J.} and Gabriel, {T. S.J.} and M. Starr and Rice, {M. S.} and J. Frydenvang and Wiens, {R. C.} and W. Rapin and S. Nikiforov and D. Lisov and M. Litvak and F. Calef and H. Gengl and H. Newsom and L. Thompson and S. Nowicki",
note = "Funding Information: The authors are grateful to JPL for developing and operating the MSL Curiosity rover mission and to the Mars Science Laboratory team for facilitating the multinational collaboration involving scientists from the United States, Denmark, France, Russia, and Canada to synthesize results from several MSL instrument data sets to make this work possible. We also would like to individually thank Marion Nachon, Abigail Fraeman, and Vivian Sun for helpful conversations regarding aspects of this work. This work was supported by the Mars Science Laboratory Participating Scientist Program, the Los Alamos National Laboratory Center for the Study of Earth and Space, the NASA Earth and Space Exploration Fellowship, the Elwha Stipend of Western Washington University, and the Carlsberg Foundation. The authors acknowledge Research Computing at Arizona State University for providing HPC, storage, etc., resources that have contributed to the research results reported within this paper (URL: http://www.researchcomputing.asu.edu). All data used for this work are available on the NASA Planetary Data System via links on the MSL page (URL: https://pds-geosciences.wustl.edu/missions/msl/). Funding Information: The authors are grateful to JPL for developing and operating the MSL Curiosity rover mission and to the Mars Science Laboratory team for facilitating the multinational collaboration involving scientists from the United States, Denmark, France, Russia, and Canada to synthesize results from several MSL instrument data sets to make this work possible. We also would like to individually thank Marion Nachon, Abigail Fraeman, and Vivian Sun for helpful conversations regarding aspects of this work. This work was supported by the Mars Science Laboratory Participating Scientist Program, the Los Alamos National Laboratory Center for the Study of Earth and Space, the NASA Earth and Space Exploration Fellowship, the Elwha Stipend of Western Washington University, and the Carlsberg Foundation. The authors acknowledge Research Computing at Arizona State University for providing HPC, storage, etc., resources that have contributed to the research results reported within this paper (URL: http://www.researchcomputing.asu.edu ). All data used for this work are available on the NASA Planetary Data System via links on the MSL page (URL: https://pds-geosciences.wustl.edu/missions/msl/ ). Publisher Copyright: {\textcopyright}2020. The Authors.",
year = "2020",
month = mar,
day = "1",
doi = "10.1029/2019JE006180",
language = "English (US)",
volume = "125",
journal = "Journal of Geophysical Research: Planets",
issn = "2169-9097",
publisher = "Wiley-Blackwell Publishing Ltd",
number = "3",
}