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Rare fossil called 'phenomenal'
It arrives at VMNH for study, future exhibit
Bill Hamlin (from left), Boxley vice president of aggregate operations; Dr. Alton Dooley of the Virginia Museum of Natural History; and Charles Craddock, superintendent of Boxleyâ€™s Fieldale quarry, look over the stromatolite fossil as it is delivered to the museum Wednesday. (Bulletin photo)
Thursday, July 3, 2008
It has not gotten around much in 500 million years, but a six-foot stromatolite moved Wednesday from its Cambrian-age resting place near Roanoke to Martinsville.
A truck delivered the recently discovered fossil to the Virginia Museum of Natural History (VMNH) from Boxley Materials Co. It is the first intact stromatolite found in Virginia and is unusually large, said Alton "Butch" Dooley, assistant curator of paleontology at VMNH.
The six-foot fossile was discovered May 13 at the Boxley Blue Ridge Quarry by a loader operator. Richard Benge was moving a pile of stone to a rock crusher when he noticed a rock that looked like a large turtle, said Bill Hamlin, vice president of aggregate operations at Boxley Materials. Benge moved the stone aside for safekeeping and went about his business.
The company geologist was called to look at the bizarre figure to determine what it was. "For the next several weeks, a lot of pictures went back and forth with different educational instutitions," said Hamlin. Boxley called VMNH, where Dooley is a paleontologist.
At that time, Dooley was in Wyoming on a dinosaur dig. "I wasn't too excited about it" at first, he said. "These things are found all the time."
However, when he saw the stromatolite in person, he was amazed. It is "pretty rare to get a complete one," Dooley stated, let alone one that is six feet across. "I couldn't believe how complete it is and how big it is."�
Ninety-nine percent of stromatolites are not found intact but rather seen as a cross section, he said. The biggest Dooley has seen was three feet across, he added.
Hamlin said, "We find little itty bitty stromatolites all the time, but to find one this big that's 500 million years old is pretty phenomenal."
Dooley explained that a stromatolite is "an algal mat" which is based on "single-celled algae, essentially bacteria, that grow in colonies on the sea floor." The top surface of a living stromalite is sticky and traps mud and dirt, building up layer after layer, which forms into a dome shape.
Since there still are some living stromatolites today, they can aid in the study of the fossils, Dooley said. They can be found in "Australia, the Bahamas and a few other places." Stromatolites now live in intertidal zones, between the low tide and the high tide marks.
"Without the living ones, we probably wouldn't be able to figure out what these things are," Dooley said. By studying the size, shape, surface and geological setting of both living and fossilized stromatolites, scientists can document changes that have happened to these algae colonies over time, he added.
There has been evidence collected from stromatolite fossils that indicates that they may have lived in a broader range of places on the ocean floor before certain factors, such as possible predators, caused a change in their living locations, he said.
The surface of this recently discovered stromatolite has stress fractures from stone movement over time. There also are a few lines that Dooley plans to examine more closely because they could be trace fossils. "We usually look at the top for trace fossils," he stated, noting that a trace fossil is a fossil left behind on a fossil from a different organism.
Dooley said Boxley "showed good foresight" and is committing "a real public service to make sure everybody gets to enjoy this thing."
Boxley "could just as easily have ground this thing up and used it as road fill," but it had it examined and called the museum. He added that "a lot of neat finds like this probably never come to the light of day" because people don't realize what they are or what to do with them.
Over the next couple of months, Dooley plans to analyze the stromatolite to learn about the geographic setting it was in as well as "to document how much it looks like living ones," he said.
The museum will create a display around the the stromatolite within a few months, he said.