Dinosaurs did not in fact die out all at once 65 million years ago, according to an Alberta paleontologist. University of Alberta professor and researcher Larry Heaman announced that he and colleagues had found a dinosaur bone 700,000 years after dinosaurs were thought to be extinct.
The discovery is sending ripples through the scientific community because of the innovative dating technique used to date the bone. The dating method, known as uranium lead dating, has been around for some time, according to Heaman, but this is the first time the technique has been applied to bone.
It is also the first time a bone has been directly dated after the time when dinosaurs were thought to be extinct, 65.5 million years ago.
“We knew right away that this was going to be really controversial,” said Heaman.
“At first, we were really excited. We knew this was going to change a whole paradigm; that a single meteorite didn’t wipe out the dinosaurs as scholars had originally thought.”
Heaman said there was initial difficulty getting a paper published on the discovery, as the idea that meteorites may not have killed the dinosaurs as quickly as previously thought led to backlash from the scientific community.
“It does change how we think about extinction events, that maybe they’re not always as abrupt as we make them out to be,” Heaman said.
According to Heaman, the bone is from an Alamosaurus, a type of large, plant-eating dinosaur. He said it was found just outside of Farmington, New Mexico.
“[Alamosaurus’] were giant 30 ton or so reptiles with legs about the size of elephant legs. A lifespan about as long as an elephant’s too,” Heaman said. “They had very long necks and tails, were plant-eaters, and are considered to be one of the last dinosaurs to die out.”
Although finding dinosaur bones in northwestern New Mexico is not uncommon, the placement of the bone in regards to geological layers is, Heaman explained.
When reading layers of rock like a timeline, there is a very distinct layer with a high percentage of iridium in it. Since meteors have a high concentration of iridium, it is generally thought that this layer of rock indicates the time when a meteorite hit Earth destroying the dinosaurs.
However, Heaman said the Alamosaurus bone was found above the iridium line, indicating the dinosaur died after the impact of the meteor.
Though there are no theories currently as to how the dinosaur survived the meteorite, as the discovery is only recent, Heaman said there were other bones from around the same time period.
“There were six or seven other species identified, including a T. Rex, all of which have yet to be dated,” Heaman said.
Heaman said he believes this is just the start of decades of research into the subject, and he hopes to improve the precision of the uranium-lead dating technique.
“We’re certain dinosaurs died out over a one to two million year period, but little is known of the details over this period,” he said.
“That’s what we hope to discover.”