fossiil

A fossil is the preserved remains, impression, or trace of life from geological history. Body fossils include bones, teeth, shells, wood, and other hard parts; trace fossils include footprints, burrows, nests, and coprolites. Microfossils such as pollen and foraminifera are also important for understanding past environments and aiding dating.

Preservation occurs through several pathways. Permineralization fills spaces with mineral-rich fluids; replacement substitutes the original material with minerals; carbonization leaves a thin carbon film of the organism; impressions capture external forms; amber entrapment preserves small organisms in resin; freezing, desiccation, or preservation in tar pits can also occur. Most fossils form when remains are buried rapidly in sediment, and conditions limit decay and scavenging.

Dating fossils relies on relative methods, such as stratigraphy and fossil assemblages, and absolute methods, including radiometric dating. Carbon-14 dating is used for relatively recent specimens (up to about 50,000 years), while older rocks often require uranium-lead, potassium-argon, or other techniques. The fossil record documents the history of life, major evolutionary transitions, and changes in past climates and environments.

Notable concepts include Lagerstätten, sites with exceptional preservation that reveal details of ancient ecosystems. Fossils underpin paleontology, comparative biology, and paleoclimatology, and have practical uses in petroleum geology and environmental reconstruction. Fossil fuels—coal, oil, and natural gas—are energy resources formed from ancient biomass over long timescales. Protecting fossil sites and regulating collection are common ethical and legal considerations in modern scholarship.