Fossil-less Fuels

We're taught that fossil fuels are the product of ancient life forms being subjected to millions of years of high heat and pressure.  But, there's long been a school of thought that at least a percentage of our oil and natural gas deposits are not biogenic, but abiotic--not derived from plants or animals (previous blog here).  For instance, there are hydrocarbon deposits found at depths that seemingly defy a biogenic source.  It's hard to explain the high helium content in some natural gas fields.  Et cetera.

Research this week in Science Magazine (subscription required) adds fuel to the abiotic theory, and more.  From an article on that research:

Hydrocarbons in the fluids spewing from a set of hydrothermal vents on the seafloor of the central Atlantic were produced by inorganic chemical reactions within the ocean crust, scientists suggest. The finding holds possibly profound implications for the origins of life.

The Lost City hydrothermal field, which sits on the side of an undersea mountain about 2,500 kilometers east of Bermuda, was discovered in December 2000. Unlike most hydrothermal vents, which crop up along midocean ridges where tectonic plates spread to form new seafloor, those of the Lost City lie about 15 km west of the Mid-Atlantic Ridge on ocean crust that's about 1.5 million years old. Accordingly, the chemistry of the fluids surging from the Lost City vents differs radically from that found at other hydrothermal sites, says Giora Proskurowski, a geochemist at Woods Hole (Mass.) Oceanographic Institution.

...

Lost City fluids also contain small quantities of hydrocarbons such as methane, ethane, and butane. A number of clues suggests that those substances, whose natural production usually results from the long-term heating of sediment rich in organic matter, were actually produced by inorganic chemical reactions, Proskurowski says. First, the rocks beneath the Lost City don't contain large amounts of organic matter. Second, the hydrothermal fluids are rich in dissolved hydrogen but contain a much lower than normal concentration of dissolved carbon dioxide. This suggests that what are called Fischer-Tropsch inorganic chemical reactions, which convert carbon dioxide, carbon monoxide, and hydrogen into hydrocarbons, generated the substances.

There's both science and politics in the debate over the formation of oil and natural gas.  Just because at least some of the fuel is being created abiotically doesn't mean that we shouldn't treat it as a fossil fuel when it comes to carbon emissions.  It's not renewable in the sense that energy from wind and hydro are.  However, abiotic hydrocarbons are being created at some unknown rate.  That spins into the debate about peak oil concerns, on and on.

Although some types of microorganisms that inhabit the mineral chimneys in the Lost City may have generated a portion of the fluids' dissolved methane, none found there could have produced the ethane, butane, or other organic compounds in the vents' brew. Finding butane in the fluids is particularly important, because that hydrocarbon is a building block for some of the organic substances found in cell membranes, Proskurowski notes.

"If what they've found is right, it has significant implications for the origin of life," says Allan J. Hall, a geochemist at the University of Glasgow in Scotland.

Robert M. Hazen, a geophysicist at the Carnegie Institution of Washington (D.C.), agrees: "This is an exciting finding ... that demonstrates there are so many ways to make hydrocarbons in an abiogenic setting." The largest barrier to making the complex, sulfur- and nitrogen-bearing molecules characteristic of living organisms is creating long-chain hydrocarbon precursors like those found in the Lost City fluids, he says.

Methane is supposed to be one of the basic chemicals in the primordial soup.

Comments

[Gordon R. Durand]

Nice post. When you have time you should read The Deep Hot Biosphere: The Myth of Fossil Fuels by Thomas Gold

I first read of maverick cosmologist Tommy Gold twenty years ago in The Atlantic Magazine, February 1986, which I have on my desk at this moment:

"The Origin of Petroleum" by David Osborne. If a controversial new theory is correct, the earth may contain a virtually inexhaustible supply of oil and gas. Huge reservoirs may exist where geologists have never thought to look.

This was his last book. Thomas Gold died in 2004.

[Gordon R. Durand]

I should have read your previous post first. I see you have read Thomas Gold's book.

[Kenneth Burton]

Oil is renewable with a problem, It takes an ice age to produce more, have even the Oceans freeze. Have the fish seek survival in the underground rivers, then seal them into them with the ice moving the ground. Cook slowly. Stir every few decades. Repeat Ice ages to needed oil production rates.

Job 38:30 The waters are hid as with a stone, and the face of the deep is frozen.