Summerasaurus Part VI: Un-jacketing dino bones in the Vertebrate Palaeontology Lab

Posted: September 9, 2011 - 08:52 , by admin

Today, we thought we’d offer you a behind-the-scenes look at the Vertebrate Palaeontology Lab to see what happens to dino bones between being excavated and being put on display or used for research.

Unopened plaster field jackets stored on metal shelves.

Field jackets about to be opened are stored in the Vertebrate Palaeontology Lab.

When dino bones arrive from the field, the rock matrix they are embedded in is still securely encased in a plaster and burlap field jacket (almost like a dino mummy). The jackets are carefully labeled so that palaeontologists know where they come from and have a description of what is inside (although the jackets can offer amazing surprises!).

Once a jacket is sawed open using a cast cutter, the delicate work of separating rock from fossilized bone begins. This involves a variety of tools, such as airscribes (mini jackhammers), dentist drills, small picks, and brushes that can precisely chisel the rock away from the bone – a process which can take months, even years! It takes far longer to extract a single fossil from rock matrix in the lab than it took to excavate the bone in the field.

Chris at work in the lab cleaning the fossil.

Chris McGarrity, a graduate student in Palaeontology, uses a fine-pointed dental drill to separate the rock from fossil vertebrae. Clearing the rock from inside and in between the intricate vertebrae is particularly difficult and delicate work!

Extracting a bone from the rock that has preserved it throughout the millennia is a tricky business. The fossilized bone may look very similar to the surrounding rock, or the bone may be fractured into small pieces within the rock which then needs to be reassembled like a complex 3D jigsaw puzzle. As palaeontologists expose more of a bone, they must continuously make decisions about how much rock to remove, how stable is the bone, and how the all the bone fragments fit together again – it is a real art.

Chris at work in the lab injecting glue into a fossil with a syringe-like tool.

Chris is injecting consolident (glue) into a fossilized tibia to ensure that its fragments remain intact. The fossil is brittle and the glue prevents fragments from flaking away. Note the pterodactyl tattoo on Chris’s arm – the mark of a dedicated palaeontologist!

When the correct place for a bone fragment has been determined, it is glued into place. When an entire bone is completely free from the rock, it is consolidated with a final coat of clear glue.

Cleaned fossils are placed back in the collections lab on flet lined plaster cases.

Dinosaur limb bones are stored in individual felt-lined and numbered plaster cases.

For large bones, such as the ones pictured above, a custom-made case is created from plaster lined with soft acid-free polyester felt, much like the inside of a musical instrument case. The case supports the brittle fossil to ensure its safe storage and transportation within the ROM. If a palaeontologist needs to consult a fossil for their research, it can easily be taken out of its case. If the fossil is very brittle, a plaster case will be made for the opposite side so the full specimen can be studied without putting it at risk.

Over the decades, ROM palaeontologists have extracted thousands of large and small dinosaur bones from field jackets. Stay tuned to find out where we keep them all!

Want to learn more about horned dinosaurs and how they lived? Visit the ROM’s James and Louise Temerty Galleries of the Age of Dinosaurs.