Prospecting
When palaeontologists are in the field, much of their time is spent prospecting—hiking and looking at the ground, searching for specimens. They look for bones weathered out of the ground and follow trails of eroded bone fragments to their sources. They try to determine how many other bones might be buried in a particular location and whether or not bones found in close proximity belong to the same creature.
Collecting
When a specimen is found, the first thing palaeontologists and technicians do is determine how the fossils are positioned in the rock. They dig down to the fossil using picks, shovels, and sometimes, jackhammers. Smaller hand tools are used to uncover enough of the specimen to determine its outline. Most of the bone is left unexposed.
They then trench around the specimen. To protect the fossils from damage, a jacket of burlap and plaster is wrapped around the top and sides of the specimen block and allowed to harden. A layer of tissue paper between fossils and jacket keeps plaster from sticking to the bones.
Crews then dig beneath the fossils, adding more plaster and burlap. Eventually the block of rock, plaster, burlap and fossil sits on a small column of rock like a big mushroom. At this stage the block is ready to be flipped over. Once flipped, the bottom of the block is then jacketed.
Once encased in multiple layers of burlap and plaster, the fossils are transported to the lab at the Museum where they are prepared and studied.
Very large specimens may be too heavy to move from the field intact. In these cases, the skeleton is separated and taken out in smaller pieces. The complete skeleton of a juvenile Gorgosaurus was removed from the field in five blocks. Even then, the largest block, containing the torso and skull, required a bulldozer to remove it.
Preparation
In the Museum’s lab, the slow task of removing the rock from around the fossil begins. Technicians use specialized tools to do this work. Preservative is applied to cracks in order to strengthen brittle elements and preparation around small or delicate fossils is done with the assistance of microscopes. The amount of information scientists can eventually obtain from a fossil depends on how meticulously it is prepared.
Once the specimen is extracted from the surrounding rock molds may be made by applying layers of liquid latex. Once dry, the mold is removed and used to create replicas (casts) for study, exchange and exhibit.
Casts are exact replicas. A well-made cast can provide as much scientific information as the original fossil, but is more durable and can withstand extensive handling.
Research
Years can be spent studying a single specimen, comparing it to similar fossils and reviewing resulting data. Confirming what type of fossil it is can require many hours of research, referencing publications and drawing comparisons with other fossils in collections around the world.
If the specimen provides new information the palaeontologist writes a paper describing the research and conclusions and submits it for publication to a scientific journal.
