gpronger's Journal: Mars Methane May be Geologic

"On Earth, the predominate source of methane is considered biological in origin, and the presence on Mars has been considered a possible indication of life on Mars. Recently, at the Lunar and Planetary Science Conference at The Woodlands, near Houston, Texas, researcher Bethany Ehlmann (a PhD student at Brown University in Providence, Rhode Island) proposed a geological process could be a potential source for methane. The information from the conference was covered in the most recent issue of NatureNews(Access needs a subscription).

The article reports that under a hydrothermal process the mineral olivine can undergo conversion to serpentine, with methane and hydrogen as a by-product.

Not surprisingly, there are potential problems with the theory. Though the presence of the mineral could have been a source of methane, the surface mineral is ancient, 3.8BY. Too old to be the source of the methane currently detected. It may be though, that the conversion is active subsurface, and the generated methane reaches the surface via fissures, etc."