An astrobiological perspective on Meridiani Planum

Andrew H. Knoll, Michael Carr, Benton Clark, David J. Des Marais, Jack Farmer, Woodward W. Fischer, John P. Grotzinger, Scott M. McLennan, Michael Malin, Christian Schröder, Steven Squyres, Nicholas J. Tosca, Thomas Wdowiak

Research output: Contribution to journalArticlepeer-review

105 Scopus citations


Sedimentary rocks exposed in the Meridiani Planum region of Mars record aqueous and eolian deposition in ancient dune and interdune playa-like environments that were arid, acidic, and oxidizing. On Earth, microbial populations have repeatedly adapted to low pH and both episodic and chronic water limitation, suggesting that, to a first approximation, the Meridiani plain may have been habitable during at least part of the interval when deposition and early diagenesis took place. On the other hand, the environmental conditions inferred for Meridiani deposition would have posed a challenge for prebiotic chemical reactions thought to have played a role in the origin of life on Earth. Orbital observations suggest that the combination of sulfate minerals and hematite found in Meridiani rocks may be unusual on the martian surface; however, there is reason to believe that acidity, aridity, and oxidizing conditions were broadly distributed on ancient Mars. When these conditions were established and how much environmental heterogeneity existed on early Mars remain to be determined. Because sulfates and iron oxides can preserve detailed geochemical records of environmental history as well as chemical, textural and microfossil signatures of biological activity, Meridiani Planum is an attractive candidate for Mars sample return.

Original languageEnglish (US)
Pages (from-to)179-189
Number of pages11
JournalEarth and Planetary Science Letters
Issue number1
StatePublished - Nov 30 2005


  • Astrobiology
  • Environmental history
  • Mars
  • Meridiani Planum
  • Microbiology

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science


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