An odd theory about oil.

 Some fuels, like peat, coal, and perhaps oil may be derived from the fossilised remains of plants and animals. Standard wisdom says all the oil and coal that we find is organic, and so must have originated with organisms.

This is testable in some cases: we can certainly find plenty of fossils in coal, confirming that coal was formed when dead plant and occasional animal matter was buried in a swamp under the right conditions. We can see peat, brown coal, black coal and anthracite, and we can show that these are always found in sedimentary rock. We call these energy sources fossil fuels because we regard them as a form of buried solar energy, fossilised sunshine.

Every so often, a scientist comes up with what sounds like a totally crackpot idea. That is, in terms of what other scientists believe, it is a crackpot idea. Alfred Wegener wanted people to accept the idea of continents moving, and people dismissed him as an eccentric or a fool. Louis de Broglie made the crazy suggestion that electrons might really be waves, and almost failed to get his doctor’s degree because of it.

Wegener died without recognition, though his theory of continental drift (which we now know in an amended form as plate tectonics) is standard stuff in your textbooks. Louis de Broglie was luckier, because Albert Einstein heard about de Broglie's strange idea, and suggested gently that de Broglie might in fact be correct, and de Broglie lived to see the electron microscope (which treats electrons as waves) become a standard laboratory tool.

Wegener’s case is a bit more typical, for few ‘crackpots’ get an easy time of it. More than that, most of the crackpot ideas turn out to be wrong. Yet without those strange ideas, science would never grow. Thomas Gold had to comfort himself with that thought, each time a geologist sneered at his ideas about where oil comes from. That, and the knowledge that scientists can change their minds.

Scientists usually work with a particular paradigm until evidence arises to make the old paradigm unacceptable. There have been many failed paradigm shifts, because scientists are only swayed by the evidence. When the scientists proposing a change are as astute and capable as the late Thomas Gold was, people need to ask themselves what evidence they should look for, either to support or refute the paradigm shift that Gold offered.

Gold was a famous physicist, one of three astronomers who worked out the steady-state theory of the universe, which has now been replaced by the Big Bang theory of the origin of the universe. He lived to see that theory overthrown, and now he was attacking an older, and more deeply accepted theory. He could not accept that our world’s hydrocarbons are biogenic, made by living things.

When we first discovered petroleum, said Gold, it was close to the planet’s surface, and chemists then thought that the only place you found carbon chemicals was in living things. They even named carbon chemistry organic chemistry, because it was the chemistry of organisms. Oil was made of organic chemicals, so obviously it had to come from organisms.

Now we know that comets contain ‘organic’ chemicals, and so does Jupiter. Nobody argues that the methane on Jupiter came from giant Jovians breaking wind, and nobody assumes there are little green people all over the comets, producing the organic stuff there. If we were to discover oil today, said Gold, we would never be so silly as to claim that it came from plants and animals, not with the knowledge we have now of other bodies in the solar system.

The geologists sneered at this. How much oil has been found in igneous rock? they asked. Gold accepted this question cheerfully. Not a lot, he said, because geologists are set in their ways, and they only drill for oil in sedimentary rock, where the oil sometimes gets trapped as it rises to the surface. He had, he claimed, extracted 12 tonnes of hydrocarbons from granite in Sweden, most of it coming from dolerite veins that have intruded into the granite from below. The veins either weakened the granite, or carried the hydrocarbon with them, he said.

The Arabian Gulf oil fields, according to Gold, have no common features at any depth, except that they are over an area of great seismic activity. This area contains 60% of the world’s recoverable hydrocarbons. From the mountains of south-eastern Turkey down to the Persian Gulf, the plains of Saudi Arabia and the mountains of Iran, there is a continuous band of oil-fields, but nobody can find an adequate supply of source rocks to account for the oil that is there.

There is simply no ‘coherent geology’ beneath the surface to explain why the oil is found there, he said. The rocks are of all types and all ages, with nothing in common. But they are all rich in oils, and the oils are chemically identifiable, right through the area. They must have a common origin, said Gold, but some of the rocks are fifty million years younger, and were formed when the climate, the biology, everything in the area had changed. According to Gold, there is just no way the oil could have come from the rocks that have formed since life evolved.

In other places as well, we find oil provinces that stretch much further than any surface geological features. The only thing that is common is the deep seismic activity.

Then we come to Gold’s other problem: where did the living things that supposedly formed the oil get their carbon? If they got it from carbon dioxide in the air, through photosynthesis, there could not have been enough for life to keep going. So, said Gold, there must have been a continuous supply of carbon compounds for life to keep going. On his calculations, the earth’s atmospheric CO₂ must have been replaced 2,000 times in the past 500 million years.

The source of our hydrocarbons, he suggested, is about 150 km below the surface, seeping upwards when it can. Look at Indonesia, he said, where the movement of the Australian plate is causing activity below the surface, and there are huge oilfields. Look at California, where two plates are separating. Look at the match-up between seismic activity and oilfields in the rest of the world, he said.

It was true, he said that we often find petroleum in sedimentary rocks, but that, he said, was merely because we have a paradigm that says that we should look in sedimentary rocks, and so we only drill oil wells in sedimentary structures.

We were trapped in a 19th century paradigm, he said, one that held, until well after Friedrich Wöhler synthesised urea and William Perkin synthesised the first organic dyes in 1856, a paradigm that is reflected in the very name of the science that Perkin initiated, organic chemistry.

Back in the 19th century, as people began to drill for oil and use it, they naturally assumed the carbon compounds were organic, formed from living things. Even Pluto has hydrocarbons, but where did Pluto’s methane come from? There are no swamps or cows on Pluto, yet there is methane there. These organic chemicals come from a distinctly non-organic background.

Just for now, the oil companies have not been rushing to take up exploration leases on the world’s granite belts. In the future, we might just see a paradigm shift that leads them to do so, but even then, the oil would still be fossilised sunshine in a sense, for all of the solar system’s other hydrocarbons must have had their origin inside the sun, or some other earlier star, and the stored energy in them is derived from a star’s nuclear furnaces.

That leaves me wondering about the Yarrabubba asteroid: might it have smashed into a large deposit of inorganic oil? The best answer: more research is needed. Science often says that.