Fossil and Fossilization

Trace fossil

indirect evidence like tracks and trails.

Bioturbation

disturbance/mixing of sediments by living organisms (often linked to burrowing/trails).

Unaltered fossil

"original material" preservation (freezing, mummification, amber, unaltered bone/shell).

Petrification

organic material replaced by inorganic minerals.

Permineralization

minerals fill voids/impregnate skeletal framework.

Recrystallization

original minerals recrystallize into different minerals.

Carbonization

organic material reduced to carbon.

Mold (mould)

imprint remains after shell/bone dissolves.

Cast

mineral-filled mold forming a copy of the organism.

Gastroliths

stones associated with organisms (listed as indirect evidence).

Coprolites

fossil feces / fecal pellets.

Burrows

preserved tunnels/borings made by animals.

Fossil

recognizable direct or indirect evidence of past life.

Taphonomy

study of fossil preservation + fossil record bias.

Altered fossil

fossil changed by mineral/chemical replacement processes (permineralization, replacement, etc.).