In honor of Earth Sciences Week, today we celebrate the 8th annual National Fossil Day!!!
National Fossil Day is organized by the National Park Service to promote public awareness and stewardship of fossils, with the goal of inspiring the next generation of paleontologists and fossil enthusiasts.
Fossils are the preserved remains of plants or animals. Just think Jurassic Park and you’re there! There might be all types of remains found in the Earth, but for such remains to be considered fossils, scientists have decided they have to be over 10,000 years old.
There are two main types of fossils, body fossils and trace fossils. Body fossils are the preserved remains of a plant or animal’s body. Trace fossils are the remains of the activity of an animal, such as preserved trackways, footprints, fossilized egg shells, and nests.
You may ask, “How do fossils form?” The way a fossil forms depends on a few things. The most important step is that the remains or traces of life must be buried, the quicker the better. The longer they remain exposed the more likely it is that they will be destroyed by scavengers or by the environment itself.
Imagine a desert versus the bottom of a deep sea… wind blasted sand dunes and hungry scavengers versus still, murky waters where gloopy mud is laid down steadily… where do you think fossils are more likely to form? Apart from burial the other key points are…
- Hard parts best. Got hard parts? Bones or shells? Then you are more likely to become a fossil because soft bits rot away quickly.
- Where do you live? If there is sediment like mud or sand being laid down then you have a chance to be buried by it and fossilised.
- The recipe for success. Once buried there is a chance minerals can start to fill gaps in your remains or even replace them, basically turning them into stone. This is when fossilisation really happens and depends a great deal on what natural minerals are in the sediment.
- And finally… with luck the rock layer you are preserved in will be eroded and your fossilised remains exposed, ready for the chance to be discovered.
Here you can see a short animation of how a fossil is made. (Credit: osisdesign.co.uk).