How are Fossils Made?

How are Fossils Made?

Let’s face it, everything dies. If you are human, some go to heaven some go to hell, some get stuck in purgatory and some of the lucky ones turn into fossils. This is true for plants and animals. So what is a fossil and how are they preserved?

When plants, animals or we die the remains are usually disposed of or they rot away and turn back into dust. But when the conditions are just perfect and remains are buried quickly say from an earthquake or volcano, the remains become fossilized.

If an animal dies at sea the carcass floats to the bottom where the bones may remain and become covered with sediment during which time they become fossilized. The same thing can happen to animals washed out to sea say in a tsunami. This explains why many fossils found are of sea animals. Over time the skeletons are further buried and pressure increases in the lower layers turning into rock.

As the skeleton is buried and surrounded by sediment turned to rock a natural mold is formed and water rich minerals enter the mold and fills the cavity. These minerals then form a cast which has the same shape as the original skeleton. After another few million years the rock surrounding the skeleton reaches the earth’s surface during mountain building, earthquakes or other natural disasters. After a while the rock cast is worn away by wind and rain which then exposes the fossil.

Discovering a fossil is very rare and is most important to fossil experts as they play an important part for scientists and geologists in providing data for helping to determine the age of not only the planet but of other types of plants and animals that are now extinct.


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