Fossilisaatioon

Fossilisaatioon, meaning fossilization in Finnish, is the process by which organic remains are preserved over geological time. It is a complex natural phenomenon that requires specific conditions to occur. For an organism to become a fossil, it typically needs to be buried rapidly after death, protecting it from decomposition and scavengers. The environment of burial is crucial, with sedimentary environments like lakebeds, riverbeds, and seabeds being particularly conducive to fossilization.

The most common type of fossilization is permineralization, where groundwater rich in dissolved minerals seeps into the porous spaces of bone, shell, or wood. These minerals precipitate out of the water, filling the empty spaces and essentially turning the organic material into a rock. Another significant process is replacement, where the original organic material is dissolved and simultaneously replaced by minerals. Casts and molds are formed when an organism decays after being buried, leaving an empty space in the surrounding sediment that preserves its shape. This void can then be filled with minerals, creating a cast of the original organism. Carbonization is another important method, where organic matter is compressed, leaving behind a thin film of carbon. This is common for plants and soft-bodied organisms.

The fossil record provides invaluable insights into the history of life on Earth, revealing extinct species, evolutionary lineages, and past environments. The rarity of fossilization means that the existing fossil record is only a partial representation of the life that has existed.