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Episode 7: What Is Fossil Preparation?


Welcome back to the New Jersey State Museum’s Ask the Experts Video Learning Library, where we’re digging into some of the most common questions people ask paleontologists about what we do and how we do it.  The last time you joined us, we were loading the fossil jackets into a truck, and carrying them back East across the country.  Their final stops are here at the paleo labs at the NJ State Museum and the Academy of Natural Sciences of Drexel University in Philadelphia.

It’s here that we take these new jackets, fresh from the field, and with any luck, end up with nice, clean, reassembled bones and skeletons.  But that's REALLY simplifying things - there are a LOT of steps to go from this, to this. But how do we get there?  What kinds of tools do we use, and how long does this kind of thing take, anyway? Let’s dig into those questions right now. 

Of course the first step is to open the jackets. 

These jackets are tough, so to open them we’ll use tools like pruning shears, saws, and sometimes even crow bars.  Hopefully the jackets have done their job and the rocks and bones inside haven’t been jostled around and nothing is loose or broken.  This one looks pretty good, so we can start prepping it. 

Just about every step of the process from here on out is called fossil preparation.  The idea here is to remove the bone from the matrix  and strengthen them so they will remain intact for a very long time. This is a lot harder than it sounds. These fossils are almost 70 million years old, and for those 70 million years, they have been cemented into this hard sandstone.

It’s our job, as fossil preparators, to free the delicate fossils from the surrounding rock. To do this we use many different tools, but it always depends on how big or fragile the bones are and how hard the surrounding matrix is.

We might use chisels and small hammers, but more often we use dental picks and toothbrushes. Another tool we use is an airscribe. Airscribes are air-powered tools,that work like miniature jackhammers. When we turn it on, this pin goes back and forth quickly and chips away very tiny bits of rock at a time.  As the rock is removed, fossil is exposed.  But it’s not just about removing the rock. 

Even the best preserved specimens are often broken up into many smaller pieces. They ARE millions of year old! It’s up to the fossil preparators to put these pieces back together, like a really difficult puzzle. For that, we use glue, and we use a lot of it. 

Well, it looks like now we can begin the last stage of fossil preparation: surface cleaning. Basically, we’re just cleaning off the excess dirt, rock, and glue from the fossil’s surface, using things like wooden coffee stirrers and even the same tools your dentist uses! 

Hopefully by now you can tell that this is an extremely slow process - it can take weeks or months to remove even a single bone. But, it’s also very rewarding.  You, as the fossil preparator, are bringing some life back into these ancient, fossilized bones after more than 70 million years.

As you can see, Brittany did a great job. The fossil is now clean, there’s no more matrix, and the fossil is now a LOT less fragile than it used to be. Researchers can now see and study all of the bone’s features, and it’s ready to become part of the museum’s collections. 

But how do we actually figure out which part of the dinosaur we have? Better yet, how do we even know which dinosaur that bone belongs to? Let’s dig into those questions next time. Until then, thanks for joining us, and as always, keep digging!