Dating a fossil
Trace fossils represent a data source that reflects animal behaviors, and they do not require the preservation of hard body parts. Some common examples are most dinosaur bones, petrified wood, and many trilobite fossils.
Many traces date from significantly earlier than the body fossils of the animals suspected to have made them. Permineralization can preserve even the most minute details including cell structure.
Very rare, and typically found in very recent fossils.
Some examples include freezing (woolly mammoths in the permafrost), mummification, fossilization in amber.
While there is no defined date, typically something must be older than 10,000 years to be considered a fossil.
The oldest fossils in the fossil record date from 3.5 billion years ago, however it wasn't until around 600 million years ago that complex, multi-cellular life began was first preserved in the fossil record.
Relative dating is used to arrange geological events, and the rocks they leave behind, in a sequence.
Fossils are important for working out the relative ages of sedimentary rocks.
Authigenic Mineralisation - A very special form of cast and mold formation where a nodule is formed around the fossil by minerals such as siderite.
In cases of rapid fosssilization, very fine details can be preserved.
Suppose you find a fossil at one place that cannot be dated using absolute methods.
That fossil species may have been dated somewhere else, so you can match them and say that your fossil has a similar age.