A broken, fossil tyrannosaurid dinosaur tooth found on the ground in the Judith River Formation in Montana.
(Lower, left) Fossil Preparator Michelle Pinsdorf extracting a fossil from a protective plaster jacket. . (Michelle Pinsdorf/NMNH-2016-00532, Smithsonian)
Giving fossils a facelift
February 27, 2017
If you think about it, a fossil has not shown its best face in a long time. If may never have shown its best face. It has spent millions of years embedded in rock or ice. It may have been embedded in tar or amber. It is a fossil preparator's job to remove a fossil from the surrounding materials. The fossil is then revealed. It can be studied and displayed. The difficulty of the preparation depends on what the fossilized organism is. It also depends on how it has changed over time.
We think of fossils as animals or plants that have mineralized (changed to rock). But, that is only part of the story. Fossils are defined as any traces of life 10,000 years old or older. A fossil can be as subtle as a footprint. Or it can be as substantial as a skeleton. Whether it mineralizes or not depends on the conditions it experiences. And how long it experiences those conditions. Living material buried in ocean sediment might get totally replaced with minerals. Living material in a peat bog might survive for thousands of years nearly unchanged.
A fossil preparator's work often begins in the field. It starts with the removal of a fossil from the landscape where it is found. Along with the fossil comes a lump of surrounding material. It is left on as protection for packaging and transport to a fossil preparation lab. There, a fossil preparator uses specialized tools to remove the material around the fossil. This will depend on the fossil. Tools may range from soft brushes to metal dental picks. Sometimes air-powered, needle-tipped jackhammers are used.
But not all fossil organisms are created equal. Usually the hard parts of an organism have fossilized. This might include bones, shells or stems. The soft parts decay or are eaten away. A fossil preparator must piece together fossilized bits of the organism. It is like a puzzle. The preparator restores missing parts using information from other sources about what they should look like. This makes a preparator part scientist, part detective, part artist and part engineer.
Preparator Michelle Pinsdorf prepares fossils for display and research. She works at the Smithsonian's National Museum of Natural History.
Learn more about her job, and how volunteers play a role, in the "Smithsonian Science How" webcast on Thursday, March 9, 2017. During Inside the Smithsonian's Fossil Prep Lab (airs at 11 a.m. and 2 p.m. EST on the Q?rius website), Michelle will take you on a tour of the Fossil Prep Lab. She will answer your questions live. You can also get teaching resources to use with the webcast.
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CRITICAL THINKING QUESTION
Why does a fossil preparator’s work not end in the field?
Write your answers in the comments section below