"New research coauthored by Dudley Herschbach, Baird research professor of science [at Harvard] and recipient of the 1986 Nobel Prize in chemistry... describes how investigators combined three abiotic (non-living) materials -- water (H2O), limestone (CaCO3), and iron oxide (FeO) -- and crushed the mixture together with the same intense pressure found deep below the earth's surface. This process created methane (CH4), the major component of natural gas."

See: Harvard Magazine article (2005-03)