What is a fossil?

What is a fossil?

Examples of fossils are the bones and skeletons of dinosaurs. But fossils are more than bones.

Dinosaur fossil

A fossil is the remains, impression, or trace of an animal from a past geologic period. Therefore, a fossil is a bone, a skeleton, a footprint, an animal or partial animal preserved in amber. 

Also, any remains of an animal that are older than 10,000 years is a fossil.  

Most animal bodies, when they die, they completely disappear due to decomposition, insects, microbes, and anything that breaks down the body. An animal body decomposes and decays at different rates of time.

But a fossil stays intact or almost intact because its body parts have escaped decomposition – maybe it has been covered in mud, volcanic ash, volcanica lava, or a mineral deposit, for example. 

Another term for fossilisation is permineralisation. Some body parts, such as tissues, are replaced with water-bearing minerals which crystallise into a solid – they are not bones, but they are still regarded as fossils.

Tortoise shell fossil
Dinosaur fossil
Fossilised shell

Photographer: Martina Nicolls


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