The principal candidates for the origin of Mars' methane include non-biological processes such as water-rock reactions, radiolysis of water, and pyrite formation, all of which produce H2 that could then generate methane and other hydrocarbons via Fischer–Tropsch synthesis with CO and CO2.
Several potential sources of Mars' methane include non-biological activities like water-rock reactions, the breakdown of water by radiation, and pyrite formation. Each of these processes produces H2 that can subsequently create methane and other hydrocarbons via Fischer–Tropsch synthesis with CO and CO2.