Fossil Formation

QUESTION: How does fossil formation occur?

ANSWER:

Fossil formation occurs when some trace of organic life (whether it be a footprint or an actual foot) is preserved beyond the original organism's decomposition. Examples include fossilized tissue, excrement, egg shells, trackways, burrows, and nests. The process of fossil formation varies depending upon the initial remains and the conditions under which they are preserved.

In some cases, organic tissues such as bones, skin and feathers, etc. are replaced by minerals from the ground through leaching. The result is a sort of statue of the original organic material. In other instances, the sediments surrounding the organic remains harden into rock, creating a mold of the original and thereby preserving its external form.

In the case of fossilized footprints, the sediments in which the print was formed can harden into rock casting a partial mold of the foot which left the print. Fossil formation can also occur when an organism becomes immersed and preserved in a resinous substance like tree sap. This sort of fossil was popularized by the blockbuster hit movie Jurassic Park. The fossilized mosquito from which the cloning scientists extract dinosaur DNA was preserved in amber. It was once believed that fossilization required long periods of time. It is now known that fossil formation can occur quickly under the right circumstances.