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Formation of methane on Mars by fluid‐rock interaction in the crust
Author(s) -
Lyons James R.,
Manning Craig,
Nimmo Francis
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl022161
Subject(s) - geology , martian , crust , mars exploration program , dike , hydrothermal circulation , magmatism , methane , atmosphere of mars , basalt , mineral redox buffer , geochemistry , astrobiology , meteorite , fugacity , atmosphere (unit) , mantle (geology) , paleontology , ecology , physics , seismology , biology , tectonics , thermodynamics
Recent spectroscopic detections of CH 4 in the atmosphere of Mars are the first definitive observations of an organic compound on that planet. The relatively short photochemical lifetime of CH 4 (∼300 years) argues for a geologically young source. We demonstrate here that low‐temperature alteration of basaltic crust by carbon‐bearing hydrothermal fluid can produce the required CH 4 flux of 1 × 10 7 moles year −1 , assuming conservative values for crustal permeability and oxygen fugacity as implied by Martian basaltic meteorites. The crustal thermal disturbance due to a single dike ∼1 × 1 × 10 km intruded during the past 10 4 years is capable of driving the alteration, if all carbon is supplied by magmatic degassing from a dike with only 50 ppm C. Atmospheric methane strongly suggests ongoing magmatism and hydrothermal alteration on Mars.