How many years does it take for a creature to change stone, the oldest fossil of a creature

At least 10,000 years.

While whether or not an organism can form fossils depends on many factors, three factors are fundamental:

1) Organic matter must have hard parts, such as shells, bones, teeth, or woody tissue. However, under very favorable conditions, even very fragile organisms, such as insects or jellyfish, are able to turn into fossils.

2) Creatures must be avoided from destruction immediately after death. If a creature's body parts are crushed, decayed, or severely weathered, this may alter or eliminate the possibility of the organism becoming fossilized.

3) Organisms must be quickly buried by something that hinders decomposition. And the type of material that is buried usually depends on the environment in which the organism lives. The remains of marine animals are often fossilized because they die and sink to the bottom of the sea, covered in soft mud.

Soft mud becomes shale or limestone in later geological epochs. Fine-grained sediments are less likely to damage the remains of living organisms. In certain fine-grained sedimentary rocks of the Jurassic period in Germany, fossils of fragile organisms such as birds, insects, jellyfish, etc., are well preserved.

In the long geological time of 10,000 years, there have been countless creatures living on the earth, and many of the remains of these creatures after death or the traces left by their lives were buried by the sediment of the time. In the years that followed, the organic matter in the remains of these creatures decomposed, and the hard parts such as the shells, bones, branches and leaves, along with the surrounding sediment, were petrified and turned into stone, but their original form, structure (and even some subtle internal structures) remained. In the same way, the traces left by those creatures when they lived can be preserved in this way.

We call these petrified biological remains and relics fossils.

The conditions for the formation of fossils are very harsh, so in billions of years of historical precipitation, only a very small part of them can be found today because they meet the conditions for formation and have been well preserved.

The oldest fossil was discovered in Canada in 2017 by British scientists, and it is a fossil of microorganisms about 4.2 billion years old, and the microorganisms that form the fossils are only one-tenth the thickness of a human hair, and they are similar to the microorganisms that currently live near hydrothermal vents in the deep sea, and they all feed on iron.

Fossil formation:

In most cases, the petrification process begins when a plant or animal dies and is quickly covered with sediment, usually at the bottom of a body of water. The loose sediment protects the remains from the elements, bacteria, and other forces that cause weathering and decay. This slowed down the decay process, so some of the remains were preserved for thousands of years (in most cases, only hard materials like bones or shells).

During this time, layers of sediment continue to accumulate above the bones. Eventually, these sedimentary layers turn into hard, solid rock. At some point after the formation of the hard rock formation, water seeps down from the rocks and washes away the preserved remains.

Due to the hard rock above, it did not fall into the clearing where the wreckage was located. This open space forms a natural animal model, perfectly preserving the shape of the original ruins.

After being buried by sediments, the biological remains and traces of life activities in the geohistorical period go through a long geological time, accompanied by the diagenesis of the sediments, and the biological remains or relics buried in the sediments undergo physical and chemical transformation (often with mineral metasomatism and filling), and finally form fossils.

First, the organism itself must have a hard body that is easy to preserve fossils, and the minerals that make up the hard body are relatively stable in diagenesis and petrification, and are not easy to decompose. Second, the environmental conditions after the death of the organism also affect the preservation of fossils, and it is only possible to form fossils if the organism is buried quickly after death, and the corpse is not swallowed by other animals and is not destroyed by external forces. Thirdly, there are later preservation conditions, and the biological remains or relics buried in the sediments will undergo various geological transformations in the long geological history, including the compaction and consolidation of the overlying huge sediments, crystallization and metamorphism under geothermal action, tectonic deformation and groundwater metasomatism.

In the process of such complex geological processes, the vast majority of organisms and their remains are destroyed, and only a very small number can be preserved as fossils. It can be seen that the complete excavation of paleontological fossils is only a very small part of the biological world that once lived on the earth. Although current technology does not allow for a very precise calculation of the probability of fossil formation, it is not too much to describe it as "1 in 10,000".

For more than 10,000 years, the biological boundary is generally 10,000 years ago, and the organisms of 10,000 years ago are paleontology, and those after 10,000 years ago are living organisms.

Fossils are the remains or ruins of creatures that lived in the distant past. In the long geological ages, there have been countless creatures living on the earth, and the remains of these creatures after death or the traces left over from life.

Many were buried by the sediment of the time. In the years that followed, the organic matter in the remains of these creatures decomposed, and the hard parts such as the shells, bones, and branches and leaves were petrified and turned into stone along with the surrounding sediment.