Methane from UV-irradiated carbonaceous chondrites under simulated Martian conditions

Andrew C. Schuerger, John E. Moores, Christian A. Clausen, Nadine Barlow, Daniel T. Britt

Research output: Contribution to journalArticle

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Abstract

A UV photolytic process was studied for the production of methane from carbonaceous chondrites under simulated Martian conditions. Methane evolution rates from carbonaceous chondrites were found to be positively correlated to temperature (-80 to 20°C) and the concentration of carbon in the chondrites (0.2 to 1.69 wt%); and decreased over time with Murchison samples exposed to Martian conditions. The amount of evolved methane (EM) per unit of UV energy was 7.9 × 10 -13 mol J -1 for UV irradiation of Murchison (1.69 wt%) samples tested under Martian conditions (6.9 mbar and 20°C). Using a previously described Mars UV model (Moores et al., 2007), and the EM given above, an annual interplanetary dust particle (IDP) accreted mass of 2.4 × 10 5 kg carbon per year yields methane abundances between 2.2 to 11 ppbv for model scenarios in which 20 to 100% of the accreted carbon is converted to methane, respectively. The UV/CH 4 model for accreted IDPs can explain a portion of the globally averaged methane abundance on Mars, but cannot easily explain seasonal, temporal, diurnal, or plume fluctuations of methane. Several impact processes were modeled to determine if periodic emplacement of organics from carbonaceous bolides could be invoked to explain the occurrence of methane plumes produced by the UV/CH 4 process. Modeling of surface impacts of high-density bolides, single airbursts of low-density bolides, and multiple airbursts of a cascading breakup of a low-density rubble-pile comet were all unable to reproduce a methane plume of 45 ppbv, as reported by Mumma et al. (2009).

Original languageEnglish (US)
Article numberE08007
JournalJournal of Geophysical Research E: Planets
Volume117
Issue number8
DOIs
StatePublished - 2012

Fingerprint

carbonaceous chondrites
carbonaceous chondrite
Methane
methane
bolides
plumes
Carbon
plume
carbon
mars
Mars
Inosine Diphosphate
methylidyne
interplanetary dust
particle mass
methane production
chondrites
dust
piles
comets

ASJC Scopus subject areas

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

Cite this

Methane from UV-irradiated carbonaceous chondrites under simulated Martian conditions. / Schuerger, Andrew C.; Moores, John E.; Clausen, Christian A.; Barlow, Nadine; Britt, Daniel T.

In: Journal of Geophysical Research E: Planets, Vol. 117, No. 8, E08007, 2012.

Research output: Contribution to journalArticle

Schuerger, Andrew C. ; Moores, John E. ; Clausen, Christian A. ; Barlow, Nadine ; Britt, Daniel T. / Methane from UV-irradiated carbonaceous chondrites under simulated Martian conditions. In: Journal of Geophysical Research E: Planets. 2012 ; Vol. 117, No. 8.
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