How did the "excrement" from billions of years ago become precious geological "shit" material?

I remember a joke: A asked B, "Do you have a copy of A Brief History of Time?" B replied, "I wouldn't pick that up even if I had time." Indeed, when we see a pile of poop, we would avoid it as much as possible, but what if it was made by prehistoric creatures?

This topic is a bit heavy, but we know that feces generally don't last long. A heavy rain, or a lucky person stepping on it, or even some passing animals yelling "Oli Gei" and then drying up, can make them disappear forever. Even if they lie in the same place, they will be decomposed by microorganisms or weathered away.

However, under certain conditions, they can also be recorded in history as "shit" and become treasures that paleontologists exclaim "really delicious!" - fecal fossils. Fecal fossils are relic fossils. Their formation conditions are the same as those of biological remains fossils. The first is rapid burial. The several situations mentioned above are the result of untimely burial, which fundamentally cuts off the possibility of fossilization. After that, the burial environment must be kept stable, so closed and calm lakes or swamps are undoubtedly ideal environments. The silt wrapped in the water not only reduces weathering, but also prevents them from being noticed by certain animals. It is for this reason that the probability of aquatic animals' feces forming fossils is higher than that of terrestrial animals.

Pictured is an exhibit in the museum: fossilized coprolites of a freshwater shark from the Mesozoic Era, Hybodon

As for the hard parts that the fossil body needs to have, although they are relatively soft, it is not impossible to achieve. Among the fecal fossils discovered so far, carnivores produce more than herbivores. This is because carnivores' food contains more calcium, phosphorus and other components, which are also produced during the microbial activity inside the feces, providing a material basis for the mineralization of feces into fossils. In addition, hard parts such as teeth, bones and scales that cannot be digested will also be excreted and become the hard parts of the fossils. These components are also the basis for distinguishing them from ordinary stones that look similar, because the content of calcium phosphate is higher.

The person with the largest collection of fecal fossils

In general, the probability of feces forming fossils is much lower than that of biological remains with shells or bones, which makes them rare and valuable. In addition, they have no fresh smell, so they can be made into beautiful ornaments, turning "waste" into "gems." For example, the spiral feces fossils produced by sharks with spiral valves in their intestines are beautiful in shape, and some are golden and noble in color.

Polishing feces into "gems"

But what paleontologists find so fascinating is not this, but the geological mysteries they contain. Through their study, they can understand important information such as the environment at that time, the relationship between species, the habits of the species, and even the health status of the individual, so they have great scientific significance.