Fossiilisaatioon

Fossiilisaatioon is the Finnish term for fossilization, the process by which organic remains are preserved in the Earth's crust. This transformation typically occurs after an organism's death, when its body or traces of its activity are rapidly buried by sediment. This burial protects the remains from scavengers and decomposition, creating an environment conducive to preservation. Over vast geological timescales, the original organic material undergoes chemical and physical changes.

There are several types of fossilization. Permineralization is common, where groundwater rich in dissolved minerals seeps into the porous structure of bones, shells, or wood. These minerals precipitate out of the water, filling the empty spaces and gradually turning the organic material into rock. Another process is replacement, where the original organic material is dissolved and simultaneously replaced by minerals. Molds and casts form when the original organism decays, leaving a cavity (mold) that can later be filled with sediment or minerals (cast). Carbonization occurs when organic matter is compressed, driving off volatile elements like oxygen and hydrogen, leaving behind a thin film of carbon. Even traces of life, such as footprints, burrows, or droppings, can be preserved as trace fossils, providing insights into an organism's behavior. The conditions necessary for fossilization are specific, requiring rapid burial, a lack of oxygen, and the presence of mineral-rich water, which is why fossils are relatively rare.