Buried Ice and Sand Caps at the North Pole of Mars: Revealing a Record of Climate Change in the Cavi Unit With SHARAD
AffiliationUniv Arizona, Dept Planetary Sci, Lunar & Planetary Lab
MetadataShow full item record
PublisherAMER GEOPHYSICAL UNION
CitationNerozzi, S., & Holt, J. W. (2019). Buried ice and sand caps at the north pole of Mars: Revealing a record of climate change in the cavi unit with SHARAD. Geophysical Research Letters, 46, 7278–7286. https://doi.org/10.1029/2019GL082114
JournalGEOPHYSICAL RESEARCH LETTERS
RightsCopyright © 2019. The Authors. This is an open access article under the terms of the Creative Commons Attribution‐Non Commercial‐No Derivs 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.
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AbstractThe cavi unit at the north pole of Mars is a deposit of aeolian sand and water ice underlying the Late Amazonian north polar layered deposits. Its strata of Middle to Late Amazonian age record wind patterns and past climate. The Mars Reconnaissance Orbiter Shallow Radar (SHARAD) reveals extensive internal and basal layering within the cavi unit, allowing us to determine its general structure and relative permittivity. Assuming a basalt composition for the sand (ε′ = 8.8), results indicate that cavi contains an average ice fraction between 62% in Olympia Planum and 88% in its northern reaches beneath the north polar layered deposits and thus represents one of the largest water reservoirs on the planet. Internal reflectors indicate vertical variability in composition, likely in the form of alternating ice and sand layers. The ice layers may be remnants of former polar caps and thus represent a unique record of climate cycles predating the north polar layered deposits.
NoteOpen access article
VersionFinal published version
SponsorsNASA Mars Data Analysis Program [NNX15AM52G]; Landmark Software and Services, a Halliburton Company