Crushed bones reveal dino stomping ground

PROVO, Utah, Oct. 15 (UPI) -- U.S. geologists say they've unearthed 4,200 dinosaur bones near Moab, Utah, and have so far identified 67 individual dinosaurs from the remains.

Brigham Young University researchers say they've also discovered nearly all of the bones are fractured.

"Although enough bones were recovered to assemble several complete dinosaurs, the vast majority of bones are broken to bits and pieces, just pulverized," said Professor Brooks Britt, lead author of the study.

The quarry where the bones were found, located west of Arches National Park, contains dinosaurs of all sizes and ages, indicating a massive die-off event. The researchers said the location of the cluster of bones, near the shore of an ancient lake bed, suggests a drought was the cause.

But the biggest puzzle is the cause of the fractures, nearly all of which were angled "greenstick" fractures that occur in fresh bones. In other words, the scientists said, the bones broke before they became brittle.

"Some of these bones were almost 5 feet long, and they are green, and you really have to work hard to shatter bone that's still green," Britt said. "That means the big boys were stepping on those things. Those would have been audible, big snaps."

The researchers posit huge, plant-eating sauropods and iguanodontids that lived more than 100 million years ago crushed the bones en route to the lake.

The bones are now housed in the university's Earth Science Museum, which will re-open soon as the BYU Museum of Paleontology.