Fossilisation

How do Fossils form?

There are many ways that fossils can form.
Below is one example to show how a creature might have died, been buried and preserved as a fossil for us to find.

1. Life

A small dinosaur loses its balance and falls off a cliff.

2. Death

It falls into a lake and drowns.

Bad news for the dinosaur but possibly good news for fossil hunters in a few million year time.

3. Burial and preservation

The dinosaur can only become a fossil if it is covered over by sediments quickly.

The soft body parts decay and rot very soon after death. This is carried out by bacteria and scavangers.

The hard body parts such as bones are all that remains.

Limestones and clays are the best rock types for preserving fossils.

Over time, the body is buried under more and more layers of sediments.

Hard body parts such as bone and teeth are replaced by new minerals such as calcite or quartz or pyrite. This process is called petrification.

The weight of the rocks above will compact the sediments further.

5. Uplift

In time, the rocks might become pushed up to form a mountain chain such as the The Alps or Himalayas.

5. Erosion and exposure
Finally after many millions of years, the rocks may become worn down enough to reveal the fossil at the surface.

The best places to find fossils is where the rocks have recently been lifted up or exposed.

Cliffs, quarries or road cuttings are also good places to look.

What if we could travel 1 million years into the future in a time machine?
There would be plenty of strange-looking fossils representing the time when mankind was on the Earth.