What is the origin of oil (and no, it does not come from dinosaurs)

It is an engine of today’s society, the reason for wars and one of those primarily responsible for climate change.

Every day more than 80 million barrels of oil are produced in the world, whose name comes from Latin and means “stone oil”.

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This viscous liquid known as “black gold” is a mixture of hydrocarbons, compounds that contain mainly carbon and hydrogen in their molecular structure.

Oil is the product of a transformation process over millions of years.

But where does it come from? Most scientists are in favor of one theory and say that the origin of oil “is well understood.” But that hasn’t stopped some misconceptions from still circulating…

The myth of the dinosaurs

It is estimated that about 70% of the current crude oil deposits were formed in the Mesozoic or Mesozoic Era, which lasted between 252 to 66 million years ago.

The Mesozoic, which is divided into the Triassic, Jurassic, and Cretaceous periods, is also known as the age of reptiles, and dinosaurs had their heyday in it.

This could perhaps explain why the wrong information has circulated.

“For some strange reason, the idea that oil comes from dinosaurs has stuck with many people. But oil comes from trillions of tiny algae and plankton,” Reider Müller, a professor of geology at the University of Oslo, told sciencenorway.no.

Illustration of an iguanodon, a genus of dinosaur that could be over 10 meters long. (GETTY IMAGES).

No one knows for sure how this myth was born, but it has also circulated in Latin America. BBC Mundo asked two Mexican experts if they were aware of this belief.

“Yeah, It is a misconception, but very common“, pointed out Darío Solano and Iza Canales, professors at the Faculty of Engineering of the National Autonomous University of Mexico, UNAM, in the Earth Sciences division.

“At least within our community, we can identify that many of the rocks that generate hydrocarbons are found in Jurassic strata, which is a period of geological time that is often associated with dinosaurs and perhaps that is the relationship that has helped to reinforce the idea that this is its origin,” explained Solano.

“It is important that these myths are debunkedFirst, to help society as a whole eliminate ignorance regarding a substance in common and widespread use, in short, just for general culture. Secondly, by advancing in the understanding of the origin of this resource, it will be possible to advance in the development of new technologies or uses,” added Canales.

The accumulation of geological layers on deposits of organic matter generates pressure and temperature conditions that allow the transformation of this matter into hydrocarbons. (GETTY IMAGES).

How is oil formed?

The protagonists in the story of the origin of oil are not large reptiles but tiny beings.

The most accepted theory about the origin of oil is the so-called organic one, according to which the resource originated from the decomposition of the remains of animals and microscopic algae accumulated on the bottom of seas and lagoons.

This theory indicates that fine sediments and organic remains are deposited in a basin, especially terrestrial or marine plants. After certain processes, kerogen is formed, which is a mixture of these organic materials, and after a long time pressure and temperature are increased, finally forming hydrocarbon chainsexplained the UNAM scientists.

The accumulation of other geological layers on top of organic matter deposits generates pressure and temperature conditions that facilitate the action of anaerobic bacteria to slowly transform organic matter into hydrocarbons with small amounts of other elements.

“In a simplified way, we can think that we cook our mixture of materials in a pressure cooker (that is, with certain pressure and temperature conditions) for a long time, until the original matter is broken down into chains of carbon and hydrogen. Something similar happens underground. Then the material needs to migrate from the rocks where it was cooked to the rocks that will store it,” the Mexican experts explained.

This theory is one of the most accepted since all the oil deposits have been found in sedimentary terrain and, in addition, they found fossil remains of animals and plants.

Where does the energy in oil come from?

Oil can also come from the transformation of organic material from ancient forests.

Within organic theory it is understood that any type of organic material can be present. In fact, the type of hydrocarbon obtained from kerogens rich in terrestrial vegetable matter is associated with gas deposits, the Mexican scientists added.

And here is another myth to clear up. Is the energy in the oil solar energy captured in photosynthesis by phytoplankton (plant organisms) and transferred to zooplankton (animal organisms)?

“No, this is a misconception,” Canales said, adding:

“The energy that we obtain today from oil is obtained by the oxidation (combustion) of hydrogen and carbon chains (hydrocarbons).“.

“It’s true that energy and matter are interchangeable, but stating it like that sounds like phytoplankton and zooplankton are solar batteries. You can rather think of it as an analog to how humans can eat many things and the body transforms food by breaking it down in our digestive system through another oxidation process (digestion) and our body takes advantage of these simpler components at the cellular level,” added Solano.

Oil extraction in the North Sea. The energy used from oil is obtained by the oxidation (combustion) of hydrogen and carbon chains. (GETTY IMAGES).

alternative theories

Some scientists have argued in the past that oil has an inorganic origin and is formed deep within the Earth without the need for the remains of living organisms.

Several of these theories were proposed as early as the 19th century, for example by Dimitri Mendeleev, the Russian chemist who published the first periodic table of elements.

The inorganic theories They argue that within the Earth’s mantle, carbon can exist as hydrocarbon molecules, mainly methane, and a large amount of hydrocarbons found in oil can be generated by processes that do not require organic fossils.

These hydrocarbons can migrate out of the mantle to the earth’s crust until they escape to the surface or remain in impermeable strata, forming oil deposits.

One version of these theories is that of the Austrian astrophysicist Thomas Gold (1920-2004), who was a professor of astronomy at Cornell University.

Gold published a study in 1992 in PNAS, the journal of the American Academy of Sciences, which he later expanded into a book with the same title, Deep Hot Biosphere.

For Gold, hydrocarbons on Earth are not the by-product of biological waste (“fossil fuels”), but were a common constituent of the materials from which the Earth formed some 4.5 billion years ago.

Gold acknowledged that the same hypothesis had already been held in the 1950s by Soviet scientists.

The theory of the inorganic origin of petroleum is not accepted by the majority of scientists

“We dare to speak for our colleagues in academia and science to say that theories of inorganic origin have not been successfully tested and that in this way it has not been possible to generate hydrocarbon in a laboratory,” said the UNAM experts.

Oil field in Iraq. The UN warns that CO2 emissions from burning fossil fuels must fall by 45% by 2030 (compared to 2010) to avoid the worst effects of climate change. (GETTY IMAGES).

One last question?

Since the organic theory of the origin of petroleum is the most widely accepted, perhaps some readers may ask themselves this question.

If the dinosaurs lived at the same time as the formation of oil in the Mesozoic, it could have happened that their remains, the organic matter of a dinosaur, fell to the bottom of the sea or lagoons and suffered a compression and transformation process, turning into oil.

“Properly, we could say that any organic matter could be present in the generation of oil,” said the UNAM experts.

“However, it is important to mention that the generation of oil is a very delicate process, and very large volumes of matter are required, which were only possible to reach because of the large volumes of plankton in the seaTherefore, volumes from other origins are not as significant,” they concluded.

Source: Elcomercio