Evidence for Seismogenic Hydrogen Gas, a Potential Microbial Energy Source on Earth and Mars

Sean McMahon, John Parnell, Nigel J F Blamey

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)
13 Downloads (Pure)

Abstract

The oxidation of molecular hydrogen (H2) is thought to be a major source of metabolic energy for life in the deep subsurface on Earth, and could likewise support any extant biosphere on Mars, where stable habitable environments are probably limited to the subsurface. Faulting and fracturing may stimulate the supply of H2 from several sources. We report the H2 content of fluids present in terrestrial rocks formed by brittle fracturing on fault planes (pseudotachylites and cataclasites), along with protolith control samples. The fluids are dominated by water and include H2 at abundances sufficient to support hydrogenotrophic microorganisms, with strong H2 enrichments in the pseudotachylites compared to the controls. Weaker and less consistent H2 enrichments are observed in the cataclasites, which represent less intense seismic friction than the pseudotachylites. The enrichments agree quantitatively with previous experimental measurements of frictionally driven H2 formation during rock fracturing. We find that conservative estimates of current martian global seismicity predict episodic H2 generation by Marsquakes in quantities useful to hydrogenotrophs over a range of scales and recurrence times. On both Earth and Mars, secondary release of H2 may also accompany the breakdown of ancient fault rocks, which are particularly abundant in the pervasively fractured martian crust. This study strengthens the case for the astrobiological investigation of ancient martian fracture systems.
Original languageEnglish
Pages (from-to)690-702
Number of pages13
JournalAstrobiology
Volume16
Issue number9
DOIs
Publication statusPublished - 1 Sept 2016

Bibliographical note

M thanks the STFC for a PhD studentship and the NASA Astrobiology Institute for additional funding (NNAI13AA90A; Foundations of Complex Life, Evolution, Preservation and Detection on Earth and Beyond). Alison Wright, Roger Gibson and Edward Lynch are thanked for contributing samples. We thank three anonymous reviewers for their insightful comments.

Keywords

  • deep biosphere
  • faults
  • fault rocks
  • seismic activity
  • hydrogen
  • Mars

Fingerprint

Dive into the research topics of 'Evidence for Seismogenic Hydrogen Gas, a Potential Microbial Energy Source on Earth and Mars'. Together they form a unique fingerprint.

Cite this