Forming Hydrocarbons in the Deep Earth

Geologists and geochemists believe that nearly all (more than 99 percent) of the hydrocar.....

Geologists and geochemists believe that nearly all (more than 99 percent) of the hydrocarbons in commercially produced crude oil and natural gas are formed by the decomposition of the remains of living organisms, which were buried under layers of sediments in the Earth’s crust, a region approximately 5-10 miles below the Earth’s surface. But hydrocarbons of purely chemical deep crustal or mantle origin (abiogenic) could occur in some geologic settings, such as rifts or subduction zones said Galli, a senior author on the study. Formation Under Extreme ConditionsA new computational study published in the Proceedings of the National Academy of Sciences reveals how hydrocarbons may be formed from methane in deep Earth at extreme pressures and temperatures. The thermodynamic and kinetic properties of hydrocarbons at high pressures and temperatures are important for understanding carbon reservoirs and fluxes in Earth. The work provides a basis for understanding experiments that demonstrated polymerization of methane to form high hydrocarbons and earlier methane forming reactions under pressure