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Degradation of 100-m-Scale Rocky Ejecta Craters at the InSight Landing Site on Mars and Implications for Surface Processes and Erosion Rates in the Hesperian and Amazonian

Sweeney, J. and Warner, N. H. and Ganti, V. and Golombek, M. P. and Lamb, M. P. and Fergason, R. and Kirk, R. (2018) Degradation of 100-m-Scale Rocky Ejecta Craters at the InSight Landing Site on Mars and Implications for Surface Processes and Erosion Rates in the Hesperian and Amazonian. Journal of Geophysical Research. Planets, 123 (10). pp. 2732-2759. ISSN 2169-9097. https://resolver.caltech.edu/CaltechAUTHORS:20181126-130009337

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Abstract

Rocky ejecta craters (RECs) at the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) landing site on Elysium Planitia, Mars, provide constraints on crater modification and rates for the Hesperian and Amazonian. The RECs are between 10 m and 1.2 km in diameter and exhibit five classes of preservation. Class 1 represents pristine craters with sharp rims and abundant ejected rocks. From Classes 2 to 5, rims become more subdued, craters are infilled, and the ejecta become discontinuously distributed. High‐Resolution Imaging Science Experiment digital elevation models indicate a maximum depth to diameter ratio of ~0.15, which is lower than pristine models for craters of similar size. The low ratio is related to the presence of a loosely consolidated regolith and early‐stage eolian infill. Rim heights have an average height to diameter ratio of ~0.03 for the most pristine class. The size‐frequency distribution of RECs, plotted using cumulative and differential methods, indicates that crater classes within the diameter range of 200 m to 1.2 km are separated by ~100 to 200 Myr. Smaller craters degrade faster, with classes separated by <100 Myr. Rim erosion can be entirely modeled by nonlinear diffusional processes using the calculated timescales and a constant diffusivity of 8 × 10^(−7) m^2/year for craters 200 to 500 m in diameter. Diffusion models only partly capture depth‐related degradation, which requires eolian infill. Depth degradation and rim erosion rates are 10^(−2) to 10^(−3) m/Myr, respectively. The rates are consistent with relatively slow modification that is typical of the last two epochs of Martian history.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2018je005618DOIArticle
ORCID:
AuthorORCID
Warner, N. H.0000-0002-7615-2524
Ganti, V.0000-0003-2165-6052
Golombek, M. P.0000-0002-1928-2293
Lamb, M. P.0000-0002-5701-0504
Fergason, R.0000-0002-2044-1714
Kirk, R.0000-0003-0842-9226
Additional Information:© 2018 American Geophysical Union. Received 22 MAR 2018; Accepted 29 AUG 2018; Accepted article online 8 SEP 2018; Corrected 16 NOV 2018; Published online 23 OCT 2018. This article was corrected on 16 NOV 2018. See the end of the full text for details. Research described in this paper was partially done by the InSight Project, Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Sweeney and Warner were also partially funded through NASA grant NNX14AL09G. Ganti acknowledges support from the Imperial College Junior Research Fellowship. We would like to thank Fred Calef at JPL for his advice with specific GIS methods. We thank JPL interns Claire Schwartz, Deborah Hernandez, Katherine Smyth, Soumya Kannan, and Jeff Green with their help mapping craters. We also thank SUNY Geneseo student Anthony Pivarunas for his help. We are especially grateful to the Mars Reconnaissance Orbiter HiRISE (University of Arizona) and CTX (Malin Space Science Systems) imaging teams for their high quality data and hard work in acquiring InSight imagery. This is InSight contribution 48. HiRISE, CTX, and THEMIS data are available through the NASA Planetary Data System (https://pds.nasa.gov/). HiRISE images and DEMs can also be accessed through the University of Arizona at https://hirise.lpl.arizona.edu/. CTX images were obtained from the Arizona State Universities' CTX Image Explorer at https://viewer.mars.asu.edu/viewer/ctx. All crater morphometry data relevant to the results of this study including measurements of diameter, depth, and rim height are available in supporting information Data Set S1. This includes measurements from the original Sweeney et al. (2016) work.
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
NASANNX14AL09G
Imperial College LondonUNSPECIFIED
Subject Keywords:InSight; impact craters; Erosion rates; Mars; Elysium Planitia; surface processes
Issue or Number:10
Record Number:CaltechAUTHORS:20181126-130009337
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20181126-130009337
Official Citation:Sweeney, J., Warner, N. H., Ganti, V., Golombek, M. P., Lamb, M. P., Fergason, R., & Kirk, R. (2018). Degradation of 100‐m‐scale rocky ejecta craters at the InSight landing site on Mars and implications for surface processes and erosion rates in the Hesperian and Amazonian. Journal of Geophysical Research: Planets, 123, 2732–2759. https://doi.org/10.1029/2018JE005618
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91172
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:26 Nov 2018 21:40
Last Modified:03 Oct 2019 20:32

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