1. A fossil is the preserved remains of a once-living organism.
Fossils
A fossil is the preserved remains of a once-living organism.

2. HOW IS A FOSSIL FORMED? 2. Layers 1. Sediment 3. Movement 4. Erosion
More sediment layers accumulate above the animal’s remains, and minerals, such as silica (a compound of silicon and oxygen), slowly replace the calcium phosphate in the bones.
1. Sediment
An animal is buried by sediment, such as volcanic ash or silt, shortly after it dies. Its bones are protected from rotting by the layer of sediment.
3. Movement
Movement of tectonic plates, or giant rock slabs that make up Earth’s surface, lifts up the sediments and pushes the fossil closer to the surface.
4. Erosion
Erosion from rain, rivers, and wind wears away the remaining rock layers. Eventually, erosion or people digging for fossils will expose the preserved remains.

3. Types of Fossilization

4. 1. Carbon Film
The result of the breakdown of organic material and the subsequent deposition of the resulting carbon

5. Petrification - occurs when the organic matter is completely replaced by minerals and the fossil is turned to stone.
Can happen in two ways…

6. 2. Permineralization
Where the pore spaces of an organism are filled with a mineral – bone, teeth and many marine organisms
The minerals being deposited produce stony fossils that still contain a good deal of their original solid material.

7. 3. Replacement
The process in which the organic material of an organism is replaced by a mineral
Bones, shells and wood are best preserved in this manner.

8. 4. Cast
The result of the naturally filling in of a mold after breakdown of an organism

9. 5. Mold
An impression left in the host rock by an organism

10. 6. Simple Burial
The burial of an organism with no alteration of the hard parts