A paleontologist's worst nightmare: a fossil bone is found lying on the ground. Where in the earth's strata did it come from? How does it fit into the evolution of that creature? Or, is the fossil even real?
Now, thanks to a new geochemical method developed by Temple University graduate student Doreena Patrick, scientists have a new tool to aid them in placing loose fossils back into the earth's strata or determining the fossil's legitimacy.
"Paleontologists need to know where a fossil goes in the strata in order to understand the grand picture of evolution, as well as the evolution of that creature," says Patrick, who conducted her research under Temple geology faculty members David Grandstaff and Dennis Terry. "What I wanted to do, ultimately, was be able to place a fossil back into its correct strata, which is called 'fossil provenience.'"
By analyzing a fossil bone for rare earth elements (REE), which are located at the bottom of the periodic table, Patrick is able to identify a unique signature for that bone and match it with other fossil material from the same strata.
"During the fossilization process, the calcium in the bone is replaced by trace elements, some of which are rare earth elements," she adds. "The REEs that are within the bone can tell where in the earth's strata that bone was originally located."
Patrick, who earned her bachelor's degree in chemistry from Temple in 1984, found that the trace elements are taken in preferentially, depending upon where in the strata the bone is sitting. The bone will pick up the rare earth elements in direct proportion to the amount of rare earth elements in that particular strata, earning it a unique rare earth signature.
A resident of North Wales, PA, Patrick says the studies have revealed that it takes, theoretically, about 10,000 years for a fossil bone to pick up its signature.
"That bone's signature can then tell me, with its concentration of rare earth elements, where in the earth's strata the bone had been sitting," she says.
Since presenting her initial findings at the Geological Society of America's national meeting last November, Patrick has received requests to test bones for fossil provenience from universities and museums in Arizona, Montana, Oregon, South Dakota, Utah, and Wyoming.
"It's important to know where in the earth's strata these fossils came from," says Patrick, who will receive her master's degree in May. "Otherwise, it's just a bone sitting in a museum."
Patrick's new technique, which uses only one-fifth of a gram or less of bone material for analysis, can potentially be valuable in detecting "fakes," in which composite creatures or species are made from different fossils.
As an example, Patrick points to the "archeoraptor," which was put on display a few years ago.
"Someone took dinosaur bones and put them together with the bones of a newer species of bird and tried to pass it off as a very important new species," says Patrick, a native of Northeast Philadelphia.
"The 'archeoraptor' would have been considered a major find, but it happens more frequently with smaller fossils," she adds. "It happens on a daily basis with things like dinosaur eggs, where people are trying to create eggs and say they're original. In actuality, the pieces are coming from very different spots."
Using her new technique, Patrick would be able to compare the rare earth signatures of the bones or pieces to see if they matched. "If they're not all from the same strata, they will not have the same signature."
Patrick, who taught chemistry, math, and physics for 15 years, became interested in geology when she accompanied her oldest son on a dig in Utah a few years ago.
"When the paleontologist at the site found out I had a degree in chemistry, he suggested I pursue geochemistry, since there's a shortage of geochemists working in paleontology," she says.
She returned to Temple in January 2001 to major in geology, and while working on her thesis about rare earth elements, began to look at bone types and the amount of rare earth elements they contained.
"The preliminary research was successful in identifying a fossil to its original unit from the Pierre Shale, near Chamberlain, South Dakota, and fossils from other geographic locations in Oregon, Wyoming and Montana," says Patrick. "This type of tool had not been available to scientists prior to this research."
Now, thanks to Doreena Patrick, it is.
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