How long does fossilisation take?

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What is the minimum amount of time it takes to fossilise something? (asked by Nick)


Fossils are defined as the remains or traces of organisms that died more than 10,000 years ago, therefore, by definition the minimum time it takes to make a fossil is 10,000 years. But, that is just an arbitrary line in the sand – it means very little in terms of the fossilisation process.

Fossil002The actual process of fossilisation is highly variable. Really, it is a catch-all term for all processes which yield traces or remains of dead organisms. Assuming we’re talking about preserved remains and not trace fossils, the process of fossilisation that we are usually dealing with is permineralisation, whereby minerals are incorporated into the structure of the preserved tissue (bone, flesh, feathers, etc). During this process, liquids and gases from the living organism are slowly replaced by mineral-rich water. Overtime, the minerals fill the empty spaces and we are left with the familiar structure of a fossil – a living organism that appears to have been turned to stone. Other forms of fossilisation can involve replacement of the original mineral content of the organism with different minerals, or recrystalisation of the same minerals into different forms.

Trace fossils, on the other hand, form when the remains of the organism decay, leaving an empty space or cast of the original organism. Alternatively, they can be formed by compression which can leave a compressed fossil of the original organism, or a trace fossil if the remains are later destroyed.

Fossil003One thing all types of fossilisation share in common is that they require the dead organism to be trapped underneath layers of sediment. This is what makes the fossilisation such a rare event – if the organism is left exposed after death it will usually be destroyed by decay and scavenging before it has a chance to be fossilised. But, under the right conditions, fossilisation can occur relatively quickly – in the ballpark of hundreds or thousands of years.

Let’s consider just permineralisation – what most of us think of when we think about fossilisation. Permineralisation requires a good availability of minerals such as sulphur, iron, carbon and silica, in the water or sediments around the fossil. The more minerals available, the more rapidly fossilisation can occur, assuming other conditions are optimal.

Fossil004The speed at which this occurs will also depend strongly on the size of the organism – tiny organisms, eggs or embryos can actually fossilise really quite quickly. Perhaps in a matter of weeks or months. Eggs may be particularly good for rapid natural fossilisation, too, as in many marine species they show adaptations to slow the rate of decay (a good idea if your method of fertilisation involves floating around in the sea for an extended period of time!) which offers a larger window of opportunity for fossilisation. In the laboratory, paleontologists have been able to fossilise lobster and shrimp eggs in just 2 – 8 weeks!

Similarly, researchers in Washington have developed a method that can speed up the process of wood petrification (which begins with permineralisation) in the lab, producing chemically petrified wood in just a matter of days!

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13 comments on “How long does fossilisation take?

  1. There was a fossilized cigarette lighter found in a
    Drained lake with a date etched in it. Why then would
    It be said that it takes 10,000 years for a fossil to be
    Created?????? I think this proves it’s way off

    • Hi Bev,

      Please can you back this claim up with some evidence? Do you have a link to a news article about this remarkable discovery? Also, if you read the long answer you’ll see that fossilisation can take anywhere from a few days to tens of thousands of years, depending on the conditions. So I’d say this fossilised lighter must have experienced great temperature and pressure over a short period of time.

      Thanks for reading!

      • Was the lighter made of metal? Fossilisation as I know it is the replacement of soft tissue cells with mineral deposits. Metal will not fossilise in this way. Plastic certainly won’t.

  2. The other day i found a very large bird egg in the very final
    Like the last of the last an i looked at it today and it turnd to stone
    And i was able to identify a bird shaped creature in the middle of
    The egg. Ive been trying to get into contact to some one that
    Is able to identify what species of bird and carbon date it.

  3. Actually fossilization has happened way back when it flooded 40 days and 40 nights during Noah’s times. Fossilization happened one time big time. Why? It’s because if fossilization will happen in 10,000 years, it actually won’t since decomposition will occur not decomposition. I’m sorry, but with all your respect, this article is ultimately WRONG; it goes against the Bible, God’s Word. The Bible is the only true evidence that everything happened that time.

    • umm and thats why GOD is fake, made up, ideological just like all religions…. root of all evil really, i feel its a big part why humans are gonna be stuck in an evolution slump…. because people are seriously so naive believing in such ridiculous fairy tales …. i grew out of santa when i was fairly young…….. humans have to figure out consciousness really soon ….. or humans very very very short experiment which we call life will not last much longer…. and you should probably keep your IDEOLOGIES OUT OF SCIENCE ……. 46-2 …. CHROMOSOMES… CONSCIOUSNESS is key… vatican pedophiles know how the pyramids were build… i will telepathically in-pregnant your wife…like mother mary…

      • Stalin , Pol Pot , Mao were evil and caused millions to die . They were all atheist . If there is no God , then we are all cactus very soon. I am glad to have religious faith that gives me peace of mind and ethical guidelines . A Christian is one who follows Christ not one who sais they are Christian . Pedophiles hide in churches . They are NOT Christian !

  4. I have personally seen, on the south ran Gabriel river, in Texas, dinosaur footprints from millions of years ago, next to wagon trails made by early settlers to central Texas in the 1800s that were fully fossilized, hard as a rock limestone… it doesn’t take long for mud to turn into rock.

    There are other places where people have found human footprints next to dinosaurs footprints, and people argue profusely that they were made at the same time because “it takes millions of years to make a fossil”… whereas it was likely that some native Americans were walking a river bed looking at the dinosaur footprints wondering what type of creature was so heavy that it could crush rock beneath it’s feet, and wondered if it would attack them in their sleep… then their muddy prints turned to stone a year later…

    To say “a fossil is anything over 10,000 years therefore it takes 10,000 years to make a fossil” is not only true but inaccurate. That is like saying “the definition of a cake is anything over 10,000 years old therefore it takes 10,000 years to make a cake… well the cake took 3 hours, but it wasnt a cake by definition until someone found it in a cave somewhere…

    This is very much “the glove doesn’t fit” lawyer speak.

  5. Does anyone know whom to talk to about finds. I’ve discovered a small fossilzed skull still in it’s process. One side of it is still exposed and teeth can be seen, on the other side it’s rock solid. I was looking for quartz in the San Luis Obispo area, and I’m hoping to learn more. But it’s no bigger than my hand.
    Please email me at

  6. Thank you very much for this article. I had been trying to understand the well-known fossil named Lucy what is actually a fossil or the actual bones of an organism. I now understand that fossils can form more quickly then I previously assumed.

  7. Fossilization can take anywhere from hundreds of years to several thousand of years. The thing is, DNA from teeth? Dental pulp provides DNA and it has a half life of 521 years. I don’t see how DNA could from teeth after 10,000 years could provide anything

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