Paleontologists in Alberta, Canada, have unearthed over 8,000 dinosaur bones in a massive prehistoric grave known as the Pipestone Creek Bonebed, or the "River of Death." Hidden beneath the slopes of a lush forest, this site has become one of the most important paleontological discoveries in North America. The excavation, led by Professor Emily Bamforth, aims to solve the 72-million-year-old mystery of how these dinosaurs met their sudden demise.
"We believe it's one of the largest bone beds in North America," Professor Bamforth said, according to BBC News. "The density of fossils in the area left us speechless."
The bones all belong to the Pachyrhinosaurus lakustai, a horned dinosaur characterized by a thick bump on its nose. Over eight thousand bones of this single species have been discovered at the site, providing a rare opportunity to study a vast sample from one moment in time.
"All the bones belong to a single community of a single animal species, extracted from a snapshot in time, and it's a sample of enormous size. That almost never happens in the fossil record," Professor Bamforth explained.
Paleontologists believe that the Pachyrhinosaurus dinosaurs were migrating together in a colossal herd over hundreds of kilometers when a catastrophic event abruptly ended their journey. "We believe it was a herd on seasonal migration that got caught up in some catastrophic event that ended, if not with the whole herd, at least with a good part of it," Bamforth said.
Evidence points to a sudden flood as the likely cause of the mass death. The rocks at the site show whorls of sediment from rapidly flowing water, stirring everything in its path. "All the signs point to the catastrophic event being a sudden flood, maybe a storm over the mountains that sent an unstoppable torrent of water toward the herd, uprooting trees and moving rocks," Bamforth noted.
As the team begins the delicate task of removing layers of dirt and dust, a jumble of fossilized bones emerges. The fossils are incredibly clustered, with an estimated 300 bones per square meter. "It's an extremely delicate task because the fossils are very close to each other," she said.
Among the discoveries is a huge Pachyrhinosaurus skull, about 1.5 meters long, nicknamed "Big Sam." Unique features found in some individuals, such as missing horns, provide insights into individual variations within the herd.
"We think that big piece of bone over there is part of a hip," Bamforth pointed out during the excavation. "Here we have all these long, thin bones. They are ribs. And this one is interesting: it's part of a toe bone. This one here, we have no idea what it is; it's a great example of a mystery of Pipestone Creek."
The excavation season has just begun and lasts until autumn. The team has barely scratched the surface of what lies beneath. So far, they have excavated an area the size of a tennis court, but the bed of bones extends a kilometer into the hillside. "That's why we keep coming, because we keep finding new things," Bamforth said.
The bones are taken to the Philip J. Currie Dinosaur Museum in nearby Grande Prairie for cleaning and analysis. The laboratory is filled with fossils, including Pachyrhinosaurus bones of all sizes, from young to old, allowing researchers to learn about the biology of the species. Studying such a large amount of material from a single species helps answer questions about its growth and community composition.
"More than half of the dinosaur species known in the world were described from the finding of a single specimen discovered. In this case, there are thousands of Pachyrhinosaurus," Bamforth remarked.
The Pipestone Creek site also holds fossils of other dinosaurs, such as Edmontosaurus, another herbivore that roamed the ancient forests. Studying these fossils is essential to understanding the ancient ecosystem that existed in northwest Alberta 72 million years ago.
The team's efforts are featured in a new BBC series that brings this prehistoric world to life using visual effects and science. The Pipestone Creek Bonebed continues to yield new discoveries, and paleontologists are confident that many more prehistoric secrets are waiting to be revealed.
"We know that every time we come here, we have the absolute certainty of finding bones. And every year we discover something new about the species," Bamforth said.
Produced with the assistance of a news-analysis system.