Fossil Recovery Method
Determining what life was like on earth millions of years ago is what a
paleontologist does on a daily basis. Although digging up dinosaur
bones is an exciting part of the job, a lot of what scientists learn does
not come from the skeleton of a Tyrannosaurus rex, but from smaller
fossils of plants and sea creatures. Many of these fossils are
difficult to find as they are embedded in rock, and attempts to remove
them can cause damage to the specimen.
This is a problem that Dr. Paul Johnston, a curator of Invertebrate Paleontology at the Royal Tyrrell Museum in Drumheller, faces on a regular
basis. During his time at the Australian National University in Canberra,
he developed a solution, making it possible to examine fossils previously
trapped in rock.
Johnston wondered if he could modify a process using latex to imprint
fossils deep within the stone. With help from technical officer Henryk
Zapasnik, he devised a system replacing the naturally occurring calcium
carbonate (which makes up the structure of a fossil) with a synthetic substitute.
The rocks are first immersed in hydrochloric acid under a vacuum to
dissolve the fossils. Liquid plastic is then forced into the rock, filling
the empty spaces and left to set for up to two weeks. When the plastic
hardens, the sample is placed in a potent hydrofluoric acid bath,
dissolving the rock and leaving behind plastic replicas of the fossils.
These replicas are less fragile than the original specimen, yet are exact
duplicates of their originals. With this method, scientists are able to
examine and catalogue fossils previously impossible to retrieve, opening
up a new area of investigation of rock types not normally available for
the standard treatment.
Though developed in the 1980s, this technology has been slow to catch on
for technical reasons. The method requires a slow-setting plastic,
difficult to find in Canada. However, Johnston has recently utilized his
technology in the projects he is currently involved in.
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