fossilizes

Fossilizes is the verb used to describe the process by which organisms or their traces are preserved in the geological record, eventually forming fossils. Fossilization is not a single event but a range of processes that depend on the material involved and the burial environment.

Permineralization occurs when mineral-rich water infiltrates porous tissues, filling spaces in bone, wood, or shells and producing a detailed mineral replica. Replacement and recrystallization involve the gradual replacement of original material by minerals such as silica or calcite, which can preserve fine structure even as the original material decays. Molds and casts form when an organism leaves an impression in sediment or when an emptied cavity later becomes filled, creating a replica of the anatomy. Carbonization preserves as a thin carbon film, especially for plants and delicate organisms. Other pathways include entrapment in amber, or preservation in ice, tar pits, or dry, desiccating environments, which can retain soft tissues or internal details that are rarely seen elsewhere.

Soft-tissue preservation is relatively rare, whereas hard parts like shells and bones fossilize more readily. Fossilization requires rapid burial and conditions that limit decay, such as low oxygen and stable chemical environments, over long timescales ranging from thousands to millions of years. The fossil record thus reflects biases toward organisms with hard parts and favorable depositional settings and is incomplete.

Fossils provide evidence for ancestry, morphology, behavior, and past ecosystems, and they are central to dating and reconstructing the history of life. Understanding fossilization helps paleontologists interpret what fossils represent and how they came to be preserved.