Impact excavation and the search for subsurface life on Mars

Charles S. Cockell, Nadine Barlow

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Because of the ubiquity of subsurface microbial life on Earth, examination of the subsurface of Mars could provide an answer to the question of whether microorganisms exist or ever existed on that planet. Impact craters provide a natural mechanism for accessing the deep substrate of Mars and exploring its exobiological potential. Based on equations that relate impact crater diameters to excavation depth we estimate the observed crater diameters that are required to prospect to given depths in the martian subsurface and we relate these depths to observed microbiological phenomena in the terrestrial subsurface. Simple craters can be used to examine material to a depth of ∼270 m. Complex craters can be used to reach greater depths, with craters of diameters ≥300 km required to reach depths of 6 km or greater, which represent the limit of the terrestrial deep subsurface biosphere. Examination of the ejecta blankets of craters between 17.5 and 260 km in diameter would provide insights into whether there is an extant, or whether there is evidence of an extinct, deep subsurface microbiota between 500 and 5000 m prior to committing to large-scale drilling efforts. At depths <500 m some crater excavations are likely to be more important than others from an exobiological point of view. We discuss examples of impacts into putative intracrater paleolacustrine sediments and regions associated with hydrothermal activity. We compare these depths to the characteristics of subsurface life on Earth and the fossil microbiological record in terrestrial impact craters.

Original languageEnglish (US)
Pages (from-to)340-349
Number of pages10
JournalIcarus
Volume155
Issue number2
DOIs
StatePublished - 2002
Externally publishedYes

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excavation
craters
mars
crater
Mars
examination
biosphere
blankets
fossils
hydrothermal activity
microorganisms
ejecta
drilling
planets
sediments
planet
microorganism
fossil
substrate

Keywords

  • Critical depth
  • Drilling
  • Excavation
  • Impacts
  • Life
  • Mars
  • Paleolacustrine

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Impact excavation and the search for subsurface life on Mars. / Cockell, Charles S.; Barlow, Nadine.

In: Icarus, Vol. 155, No. 2, 2002, p. 340-349.

Research output: Contribution to journalArticle

Cockell, Charles S. ; Barlow, Nadine. / Impact excavation and the search for subsurface life on Mars. In: Icarus. 2002 ; Vol. 155, No. 2. pp. 340-349.
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