Insights into complex layered ejecta emplacement and subsurface stratigraphy in Chryse Planitia, Mars, through an analysis of THEMIS brightness temperature data

Jones, E; Caprarelli, G; Osinski, GR

Insights into complex layered ejecta emplacement and subsurface stratigraphy in Chryse Planitia, Mars, through an analysis of THEMIS brightness temperature data

Jones, E Caprarelli, G

Osinski, GR

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Publication Type:: Journal Article
Citation:: Journal of Geophysical Research: Planets, 2016, 121 (6), pp. 986 - 1015
Issue Date:: 2016-06-01

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Field	Value	Language
dc.contributor.author	Jones, E	en_US
dc.contributor.author	Caprarelli, G https://orcid.org/0000-0001-9578-3228	en_US
dc.contributor.author	Osinski, GR	en_US
dc.date.issued	2016-06-01	en_US
dc.identifier.citation	Journal of Geophysical Research: Planets, 2016, 121 (6), pp. 986 - 1015	en_US
dc.identifier.issn	2169-9097	en_US
dc.identifier.uri	http://hdl.handle.net/10453/119049
dc.description.abstract	© 2016. American Geophysical Union. All Rights Reserved. Layered ejecta craters on Mars have been interpreted to indicate the presence of volatiles in the substrate, making them important targets for the investigation of sites of astrobiological significance. If the ejecta are associated with the presence of water in the substratum, specific surface grain size trends are expected. In this study we explore the distribution of grain sizes in the layered ejecta of impact craters located in Chryse Planitia, using Thermal Emission Imaging System (THEMIS) thermal infrared data. Ejecta grain size trends, in conjunction with ejecta mobility and lobateness values, are applied to assess the degree of surface flow of the ejecta, and in turn to constrain the plausible volatile abundance, cohesion, and fine particle content of the target materials. Craters with a larger fraction of small grain sizes in their ejecta showed greater ejecta mobility and lobateness, consistent with a water-rich and/or a low-cohesion target. Craters displaying decreasing grain size with increasing radius had smaller diameters and lower ejecta mobility and lobateness, indicating only a minimal component of surface ejecta flow. Ejecta grain size trends varied with crater diameter, from which the presence of vertical compositional stratigraphy in Chryse Planitia is inferred and interpreted. Our observations are synthesized into a number of plausible geologic scenarios for Chryse Planitia.	en_US
dc.relation.ispartof	Journal of Geophysical Research: Planets	en_US
dc.relation.isbasedon	10.1002/2015JE004879	en_US
dc.title	Insights into complex layered ejecta emplacement and subsurface stratigraphy in Chryse Planitia, Mars, through an analysis of THEMIS brightness temperature data	en_US
dc.type	Journal Article
utslib.citation.volume	6	en_US
utslib.citation.volume	121	en_US
utslib.for	040302 Extraterrestrial Geology	en_US
utslib.for	0201 Astronomical and Space Sciences	en_US
utslib.for	0402 Geochemistry	en_US
utslib.for	0403 Geology	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	closed_access
pubs.issue	6	en_US
pubs.publication-status	Published	en_US
pubs.volume	121	en_US

Abstract:

© 2016. American Geophysical Union. All Rights Reserved. Layered ejecta craters on Mars have been interpreted to indicate the presence of volatiles in the substrate, making them important targets for the investigation of sites of astrobiological significance. If the ejecta are associated with the presence of water in the substratum, specific surface grain size trends are expected. In this study we explore the distribution of grain sizes in the layered ejecta of impact craters located in Chryse Planitia, using Thermal Emission Imaging System (THEMIS) thermal infrared data. Ejecta grain size trends, in conjunction with ejecta mobility and lobateness values, are applied to assess the degree of surface flow of the ejecta, and in turn to constrain the plausible volatile abundance, cohesion, and fine particle content of the target materials. Craters with a larger fraction of small grain sizes in their ejecta showed greater ejecta mobility and lobateness, consistent with a water-rich and/or a low-cohesion target. Craters displaying decreasing grain size with increasing radius had smaller diameters and lower ejecta mobility and lobateness, indicating only a minimal component of surface ejecta flow. Ejecta grain size trends varied with crater diameter, from which the presence of vertical compositional stratigraphy in Chryse Planitia is inferred and interpreted. Our observations are synthesized into a number of plausible geologic scenarios for Chryse Planitia.

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http://hdl.handle.net/10453/119049