CH4 + CO2 + CO +complex organics.

Clearly in a non-equilibrium redox state - looks like it's busy oxidising...

http://www.theage.com.au/news/world/the-stuff-of-life/2008/03/27/1206207254203.html

The basic ingredients for life - warmth, water and organic chemicals - are in place on Saturn's small moon Enceladus, scientists say.

Their conclusion, outlined today, came after examination of data from the Cassini spacecraft which flew through huge plumes erupting off the moon's surface on March 12.

Scientists working on the US-European mission did not say they had detected any actual evidence of life on Enceladus, where geysers at its south pole continuously shoot watery plumes some 800km off its icy surface into space.

But they said the building blocks for life were there, and described the plumes as a surprising organic brew, like carbonated water with an essence of natural gas.

"Water vapour was the major constituent.

"There was methane present. There was carbon dioxide. There was carbon monoxide. There were simple organics and there were more complex organics," Hunter Waite of the Southwest Research Institute in San Antonio, Texas, told reporters.

Organic molecules contain carbon-hydrogen bonds and can be found in living things.

Waite said the material bursting out of the geysers was very much like a comet's chemistry.