Permineralization is a way of fossilizing a plant or an animal.
Permineralization is one of the ways a plant or animal can fossilize. During this process, mineral-rich water seeps into the empty spaces of an organism, leaving behind mineral deposits that slowly build up, creating a cast of the organism. In some cases, the entire plant or animal can be turned to stone in this way, in which case the resulting fossil is considered petrified. Many museums have examples of fossils that have been preserved using this method, and people can sometimes find these fossils for sale in stone shops and hobby shops as well.
Fossils are the result of permineralization.
This process is very unusual. Billions of organisms have died on Earth throughout geological history, and only a fraction of these organisms have fossilized because nature has developed a very elegant and efficient system for recycling dead plants and animals. For permineralization to occur, an organism must be rapidly covered by sediment shortly after death. Many petrified fossils are marine organisms that fell to the bottom of the ocean and became covered by sediment.
Examples of permineralization can be found in coal mines.
The permineralization process is very slow. It occurs when water seeps into the sediment that covers an organism; the sediment helps keep the organism intact, and mineralized water slowly seeps through the debris. Depending on the type of minerals involved and the conditions, petrifaction can result in incredibly detailed preservation, allowing people to differentiate individual cells in the organism, or it can create a more coarse cast.
When permineralization involves sulfur, it is called pyritization.
When petrified fossils contain mostly silica, archaeologists say that they have undergone silicification. Silicification is an excellent conservation technique that sometimes retains great detail. When it comes to sulfur, the process is called pyritization. Pyritization most commonly occurs in marine organisms. You can also find some great examples of carbonate mineralization in places like coal mines.
During the petrifaction of wood, cellulose and living tissue are replaced by minerals.
In many cases, permineralization only preserves the mineral tissue of the body, such as bones, teeth, and shells. In other cases, it fills a void left in the sediment by an organism that has since rotted away; this usually happens with fossilized leaves. In very rare cases, some or all of the soft tissue is preserved, allowing people to glimpse a body that could be millions of years old to learn more about how it works.