October 20, 2004

"Fossil" Fuels

Interesting article on Greenie Watch (no permalinks, look for the title) John Ray comments about Petroleum and the growing thought that it might be caused naturally in the earth and not be a result of biological breakdown: bq. MORE EVIDENCE THAT OIL IS NOT A FOSSIL FUEL AND IS NOT RUNNING OUT Fossil fuel may not require fossils, as the pressure of deep Earth has been found capable of creating hydrocarbons from inorganic matter. The findings, by an American team of researchers, suggest that hydrocarbons, the main constituents of fossil fuels such as coal, petroleum and natural gas, could be extracted from a virtually endless source. "These experiments point to the possibility of an inorganic source of hydrocarbons at great depth in the Earth-that is, hydrocarbons that come from simple reactions between water and rock and not just from the decomposition of living organisms," says researcher Russell Hemley of the Carnegie Institution of Washington's Geophysical Laboratory in DC. bq. There are two theories on the origin of fossil fuels, the biogenic theory and the abiogenic theory. According to the biogenic theory, fossil fuels are the remnants of ancient plant and animal life deposited in sedimentary rocks. According to the abiogenic theory, hydrocarbon deposits are primordial, being part of the Earth as it formed. The abiogenic theory holds that petroleum is produced by nonbiological processes deep in the Earth's crust. bq. For their experiments, the researchers created laboratory conditions mimicking the Earth's upper mantle, which underlies the crust at depths of about 20 to 60 kilometers (12 to 37 miles). The researchers squeezed materials common at the Earth's surface-iron oxide, calcite and water-to pressures ranging from 50,000 to 110,000 times the pressure at sea level. They then heated the samples to temperatures up to 1,500øC (2,700øF). They were able to get methane to form by reducing the carbon in calcite over a wide range of temperatures and pressures, supporting the possibility that the deep Earth may produce abiogenic hydrocarbons. bq. "This paper is important," says physicist Freeman Dyson at Princeton University in New Jersey. "Not because it settles the question whether the origin of natural gas and petroleum is organic or inorganic, but because it gives us tools to attack the question experimentally. If the answer turns out to be inorganic, this has huge implications for the ecology and economy of our planet as well as for the chemistry of other planets." Fascinating and major implications. Once we know the geological process, we can start looking for instances of them in nature and seeing what is there. Dyson is no dummy... The full paper is available here A PDF copy is available for download from there as well. Posted by DaveH at October 20, 2004 1:11 PM