In dinosaur museums, we can see fossilized remains of these animals that lived thousands of years ago in our territory. Thanks to these fossils, we can know how they lived, where they moved, and how many of these animals died. Impressive, isn’t it?
Hence the importance of these remains consists both of forming and finding them later. But what are fossils?
Fossils are remains or traces of organisms that lived in remote times; specifically, they must be more than 10,000 years old. Therefore, they are considered those between the beginning of the Holocene, the current epoch, and the Eoarchaic Era, about 4,000 million years ago. So these remains, preserved in sedimentary rocks, are the fossils.
The Process Of Fossilization
Some processes occur in the environment where the animal died. These processes generate the appropriate conditions for the organism to become a fossil. In this case, we could call them external processes.
The first process is called sedimentation. In this stage, the constant agents of the earth’s surface – air, water, and ice – are responsible for moving sediment periodically and give way to the burial of the remains of the animal, plant, etc.
Over time, more sediments are deposited on top of those that buried the organism, compacting the sediments as the weight of the upper layers increases the pressure and temperature in the subterranean environment – as a whole – chemical processes begin to occur in the rock that gives way to lithification.
Finally, there is the uplift and erosion of the area, which is relative since it depends on the geographic location of the place where the fossilization occurred.
In the process of lithification of the rock, there is an internal process called mineralization. It is where alteration of the original minerals that composed the fossil occurs.
Commonly in this process, the minerals of the sediments themselves are added or replace the minerals that form the fossil. After this chemical process – when it reaches stability in the medium – occurs the petrification of the rock.
Finally, we have mummification, where the organism is preserved almost as in life by being trapped in an impermeable material resistant to decomposition (ice, resin, etc.).
