Buried Ice and Sand Caps at the North Pole of Mars: Revealing a Record of Climate Change in the Cavi Unit With SHARAD

S. Nerozzi, J. W. Holt

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The 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.

Original languageEnglish (US)
Pages (from-to)7278-7286
Number of pages9
JournalGeophysical Research Letters
Volume46
Issue number13
DOIs
StatePublished - Jul 16 2019

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climate change
caps
mars
sands
radar
Mars
ice
poles
deposits
sand
climate
Mars Reconnaissance Orbiter
climate cycle
permittivity
polar caps
strata
basalt
water
reflectors
planets

Keywords

  • Cavi unit
  • Climate Record
  • Composition
  • Mars
  • Radar
  • Stratigraphy

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

Buried Ice and Sand Caps at the North Pole of Mars : Revealing a Record of Climate Change in the Cavi Unit With SHARAD. / Nerozzi, S.; Holt, J. W.

In: Geophysical Research Letters, Vol. 46, No. 13, 16.07.2019, p. 7278-7286.

Research output: Contribution to journalArticle

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