New Study Says Oil Came from Minerals Not Plants
By Neil Chatterjee
LONDON (Reuters) - Fossil fuels -- used for everything from keeping us warm to powering space rockets -- could have formed from minerals instead of plant and animal remains as generally believed, say U.S. and Russian scientists.
The team of geologists, including J.F. Kenney of the Gas Resources Corporation in Texas and Vladimir Kutcherov of the Russian State University of Oil and Gas, argue that petroleum originated from minerals at extreme temperatures and pressures.
They have mimicked conditions more than 100 kilometers (62 miles) below the surface by heating minerals containing carbon at around 1,500 degrees celsius and 50,000 times atmospheric pressure.
"Experiments to demonstrate the high-pressure genesis of petroleum hydrocarbons have been carried out using only 99.9 percent pure solid iron oxide, and marble...with triple distilled water," their report said.
This produced various hydrocarbons including methane, the main constituent of natural gas, and octane, the hydrocarbon molecule that is the basis for gasoline.
Other geologists say that the research, reported in the journal Nature this week, reignites a debate that is almost fossilised itself.
"It periodically comes up as an issue -- it's a possibility that some hydrocarbons formed inorganically," said Lidia Lonergan, a petroleum geologist at the Imperial College of Science, Technology and Medicine in London.
"But it's perceived that the majority of oil reserves discovered are of organic origin," she told Reuters.
Geologists say that there is overwhelming chemical and biological evidence that fossil fuels are composed of animal and plants, or organic matter. These chemical signs are also used to find oil.
A mathematical model of the researchers' process suggests that none of the ingredients of a mineral-based fossil fuel other than methane could form at depths of less than 100 kilometers, whereas petroleum is found at much shallower levels.
The conventional view is that oil forms just a few kilometers below the surface at temperatures of 50-150 degrees celsius, a process that can be recreated in the laboratory.
Petroleum that forms inorganically at high temperatures close to the Earth's mantle layer could be forced higher up by water, which is denser than oil, before being trapped closer to the surface by sedimentary rocks.
But geologists think this could not create the huge volume of proven world oil reserves -- 143 billion tonnes according to energy major BP -- that are expected to last around 40 years at current rates of use.
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