How do dinosaur fossils arise?

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Ricky Joseph

In 1971, paleontologists discovered a fossil of a velociraptor and a protoceratops that died in battle. The amazing fossil shows the protoceratops biting the velociraptor's arm while the predator digs its claws into its neck. But how do dinosaur fossils form in such detail?

It all depends, of course, on the right conditions, and not every animal that dies ends up fossilized. Recent estimates, for example, show that approximately 2.5 billion tyrannosaurs roamed the planet. Yet generations of paleontologists have found only a few hundred fossils of these dinosaurs.

So when a dinosaur died, its soft tissues - like skin, muscles, and organs - would end up as food for other dinos and scavenger animals. What was left over would end up decomposed by fungi and bacteria.

Image: ceparedonda / Pixabay

However, if a dino's carcass were covered in sediment shortly after death, some structures might end up being preserved. Most dinosaur fossils, in this sense, come from animals that died in swamps or near ponds, and so mud ended up covering their bodies before the environment degraded even the bones.

Once the dino's bones have become buried, water flowing in the soil begins to pass the small pores of the bones, leaving crystals of minerals within the bone along the way. Over thousands or millions of years, these bones eventually become rock and retain the morphologies of what was once living tissue.

This, however, is only one (the most common) form of fossilization. A fossil - not just dinos - can be formed by carbonization, or by preservation in natural resins such as amber, for example.

Discovering dinosaur fossils

As much as the planet itself looks giant and stationary, the Earth's crust is actually very dynamic. Over time, absurd pressures and temperatures in the magma below the surface move giant masses of land across the planet.

At the meeting of two tectonic plates, for example, deeper layers of soil can be stirred up and end up back on the surface after hundreds of millions of years. This, incidentally, is one of the processes by which fossils come to light and find their way into scientific publications. That's why it's not uncommon for scientists to find fossils on mountaintops.

Image: drippycat / Pixabay

Furthermore, the melting of large ice masses can also reveal fossils that were once very deep and inaccessible. Often animals more recent than dinosaurs - such as mammoths - end up preserved in great detail in the Arctic ice itself.

Finally, erosion can erode, over a long time, the topmost layers of rock, eventually revealing fossils. With a lot of determination (and a little luck) researchers can find preserved records with evidence and details about organisms that died millions of years ago.

The velociraptor and protoceratops referred to in the introduction, for example, probably died together after a landslide. Their disaster has preserved, for us, one of the most amazing records of detailed time paralyzed in rock.

Ricky Joseph is a seeker of knowledge. He firmly believes that through understanding the world around us, we can work to better ourselves and our society as a whole. As such, he has made it his life's mission to learn as much as he can about the world and its inhabitants. Joseph has worked in many different fields, all with the aim of furthering his knowledge. He has been a teacher, a soldier, and a businessman - but his true passion lies in research. He currently works as a research scientist for a major pharmaceutical company, where he is dedicated to finding new treatments for diseases that have long been considered incurable. Through diligence and hard work, Ricky Joseph has become one of the foremost experts on pharmacology and medicinal chemistry in the world. His name is known by scientists everywhere, and his work continues to improve the lives of millions.