Two-Ton, 500 Million-Year-Old Fossil
News Article: Science Daily
July 4, 2008
Virginia Museum of Natural History scientists have confirmed that an approximately 500 million-year-old stromatolite was recently discovered at the Boxley Blue Ridge Quarry near Roanoke, Virginia. This specimen is the first-ever intact stromatolite head found in Virginia, and is one of the largest complete "heads" in the world, at over 5 feet in diameter and weighing over 2 tons.
Stromatolites are among the earliest known life forms, and are important in helping scientists understand more about environments that existed in the past.
A stromatolite is a mound produced in shallow water by mats of algae that trap mud and sand particles. Another mat grows on the trapped sediment layer and this traps another layer of sediment, growing gradually over time. Stromatolites can grow to heights of a meter or more. They are uncommon today but their fossils are among the earliest evidence for living things.
The oldest stromatolites have been dated at 3.46 billion years old. They were discovered in 1999 in Western Australia, near the town of Marble Bar.
The Boxley stromatolite was discovered by Boxley employees in a pile of loose rock they were moving. The curious shape of the "rock" initiated a call to Tom Roller, Boxley's professional geologist, who immediately suspected it to be a stromatolite. Scientists from the Virginia Museum of Natural History traveled to the quarry to evaluate the discovery and confirmed it to be a stromatolite.
The stromatolite has been donated by Boxley to the Virginia Museum of Natural History, where it will be displayed in the coming months.
Although fragments and sections of stromatolites are fairly common, it is very rare for a whole stromatolite head to be collected intact. This specimen is particularly unusual because the top surface of the head is very well preserved.
"The exquisite preservation of the surface of this stromatolite will allow museum scientists a rare opportunity not only to look at the stromatolite itself, but also to look for other organisms that may have been living on our around it," said Dr. James Beard, assistant director of research and collections for earth sciences, and curator of earth sciences at the Virginia Museum of Natural History.