As a child, I was always told that when the dinosaurs died, they eventually got broken down into crude oil, which get refined into a list of products.
Well I seen a post somewhere that was saying the crude oil wasn’t made from dinosaurs. So if it’s not made from the remains of the dinos, how it is made then.
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You’re not that far off. It is from prehistoric life that gets trapped underground; it’s just that vast majority of it isn’t from dead dinosaurs. It by and large actually is formed from plant life (mostly algae) and plankton.
Bacteria, algae, and other microorganisms lived in the primordial seas. When they died, they sank to the bottom of the seabed; and only a small fraction of them would have been eaten. Thick layers of these were overlaid with silt and sand, which over time compress and harden into shale and sandstone. Under this rocky layer, the bodies of the microorganisms decay into crude oil.
Obviously, it’s a lot more complicated than that, but that’s the ELI5 version.
>I was always told that when the dinosaurs died, they eventually got broken down into crude oil, which get refined into a list of products.
You’re still very close to the truth, the correction is it wasn’t dead *dinosaurs* that broke down into crude oil, it was dead *plants, plankton, and algae*. When people say it wasn’t from dead dinosaurs, they’re just being specific about what *kind* of dead organic material became oil. It was mostly plankton not dinosaurs, so they’re right. But the “died, buried, eventually broke down under heat and pressure to become crude oil” part you described is still right!
Here’s a great resource that breaks it down in simple terms, with diagrams:
https://energyeducation.ca/encyclopedia/Oil_formation
Let’s go Sponge Bob on this one.
Plankton was the tiny, give me the Crabby Patty formula guy.
Then realize that if you have millions and millions of tiny plankton dying and falling to the ocean floor over millions of years, the carbon life juice can get squeezed out and pool together to form oil.
The key to all of this, is that is not specifically what it was made of, but what didn’t exist yet, that makes crude oil/coal.
Just as today, there was far more plant life than animal life. What didn’t exist was the fungus and bacteria to decompose dead material. When you cut your grass or the leaves fall off the trees, the process begins of decomposition. It’s how compost works. All that material breaks down and becomes fertilizer and soil. We don’t end up with millions of years of leaves laying on the ground.
In the beginning, all that dying matter just laid there getting more on top of it. Eventually it was buried so deep the pressure formed hydrocarbons.
Later, that process stopped. Organisms developed that could unlock that energy and use it for their own purposes. The accumulation stopped. That’s why there is no more coal and oil being formed. That’s why it’s getting harder and more expensive to find.
There are ways to make fuel from plants now, but it will never be as cheap as extracting millions of years of accumulation over a few hundred years like we’re doing now.
The issue (other than the dyno vs plant in natural processes) is we do not “make” crude, it is extracted for much less cost than it would take to make a similar energy storage system.
We do have large scale processes for recovering and reusing cooking and motor oil, but this only works because those items are worthless otherwise, actually they are a liability, there is a cost associated with disposing of them.
So, the companies that extract the crude oil can make huge profits, when crude prices get too low the most expensive extraction types feel the pain first( tar sands for example)
Crude oil comes largely from marine algae and zooplankton. Despite being millions of years old and cooked deep in the Earth, certain molecules called porphyrins associated with these types of life have survived in trace amounts in the oil.
The process of oil formation is incredibly complex and not fully understood, but it is a combination of heat, pressure and lack of oxygen that creates the enormous number of hydrocarbons in petroleum from dead material by way of a substance known as kerogen.
The organic material has to reach a point known as the oil window – too shallow and it never gets hot enough to turn kerogen into oil; but it can’t get too deep – above a certain point the oil will break down into natural gas. The window is roughly 50 – 120C which requires the dead material to be buried several kilometres beneath the surface.
Then there are issues of whether the rock it is in will release the oil, how the oil migrates, whether it can be trapped…
It came in great part from early plant matter that soaked all that carbon dioxide from the atmosphere and that that was buried before it could decompose, in part because decomposers were not there yet.
For example when wood first evolved that was nothing being able to eat it, so it accumulated dor millions of years and was buried, transforming to coal and oil. Then fungi evolved a way to eat wood so it stopped that process.
Thats why there wont be significant new reserves of crude that will be created.
Also imagine millions of years worth of trapped carbon dioxide being released in a couple hundred years… that what is happening today.
1. Most fossil fuel is much older than dinosaurs.
2. Terrestrial biomass (plants and animals that live on the ground) usually formed coal instead of petroleum. Petroleum is mostly from marine plankton.
3. The amount of biomass from big animals like vertebrae is actually rather small compared to plants and plankton. It doesn’t contribute significantly.
The reason you were taught that it’s from dinosaurs is because that’s fun and memorable. The point that fossil fuels are created from organic matter still comes across.
And to anticipate the obvious question: the reason oil can be drilled for on land, even though it was formed by marine organisms, is that oceans weren’t always where they are now. That’s the reason you can sometimes find fossilized shells and stuff in certain rocks.
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