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Impact Gardening as a Constraint on the Age, Source, and Evolution of Ice on Mercury and the Moon


Metadata FieldValueLanguage
dc.contributorEmily S. Costello, ecostello@higp.hawaii.eduen_US
dc.creatorCostello, Emily S.
dc.creatorGhent, Rebecca R.
dc.creatorHirabayashi, Masatoshi
dc.creatorLucey, Paul G.
dc.date.accessioned2022-10-26T23:36:15Z
dc.date.available2022-10-26T23:36:15Z
dc.date.created2020
dc.identifier10.1029/2019JE006172en_US
dc.identifier.urihttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JE006172en_US
dc.identifier.urihttps://aurora.auburn.edu/handle/11200/50426
dc.identifier.urihttp://dx.doi.org/10.35099/aurora-494
dc.description.abstractWe update an analytic impact gardening model (Costello et al., 2018, https://doi.org/10.1016/j.icarus.2018.05.023) to calculate the depth gardened by impactors on the Moon and Mercury and assess the implications of our results for the age, extent, and source of water ice deposits on both planetary bodies. We show that if the water presently on the Moon has a primordial origin, it may have been 4-15 m thick. If ice deposits are buried, they may be as shallow as 3 cm or as deep as 10 m and provide a gradient of probability for ice gardened into a column. Our calculations for gardening on Mercury show that thermal lag deposits will be reworked into the background over 200 Myr, and, thus, the most recent large-scale deposition of ice on Mercury must have occurred no more than 200 Myr ago. We also find that gardening mixes incremental layers of ice with underlying regolith and prevents the growth of pure ice deposits by continuous supply. We conclude that ice deposits on the Moon and Mercury are likely the result of sudden and voluminous deposition. Plain Language Summary The Moon and Mercury have water ice in permanently shadowed regions at their poles; however, while Mercury's poles are rich in water ice, the Moon's are relatively sparse. Impact cratering mixes surface material, bringing buried ice upward to a relatively hostile surface in a process called impact gardening. We apply a revised impact gardening model to investigate the depth from which ice is mixed upward by impacts as a function of time and discover the following: (1) Ice on the Moon may have been mixed with underlying regolith or buried under many meters of dry regolith; (2) the most recent large-scale delivery of water to Mercury happened no more than 200 Myr ago; (3) what ice exists at the poles of the Moon and Mercury was probably delivered suddenly and voluminously; and (4) the differences between the abundance of water ice on the Moon and Mercury will only become more pronounced with time as impact gardening destroys surface ice on the Moon and only scratches the surface of Mercury's extensive deposits.en_US
dc.formatPDFen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.ispartofJournal of Geophysical Research: Planetsen_US
dc.relation.ispartofseries2169-9097en_US
dc.rights©American Geophysical Union 2020. This is this the version of record co-published by the American Geophysical Union and John Wiley & Sons, Inc. It is made available under the CC-BY-NC-ND 4.0 license. Item should be cited as: Costello, E. S., Ghent, R. R., Hirabayashi, M., & Lucey, P. G. (2020). Impact gardening as a constraint on the age, source, and evolution of ice on Mercury and the Moon. Journal of Geophysical Research: Planets, 125(3), e2019JE006172.en_US
dc.subjectimpact gardeningen_US
dc.subjecticeen_US
dc.subjectpolar regionsen_US
dc.subjectMoonen_US
dc.subjectMercuryen_US
dc.titleImpact Gardening as a Constraint on the Age, Source, and Evolution of Ice on Mercury and the Moonen_US
dc.typeTexten_US
dc.type.genreJournal Article, Academic Journalen_US
dc.citation.volume125en_US
dc.citation.issue3en_US
dc.citation.spagee2019JE006172en_US
dc.description.statusPublisheden_US
dc.description.peerreviewYesen_US
dc.creator.orcid0000-0002-3173-6630en_US
dc.creator.orcid0000-0001-7939-9867en_US

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