Scientists say they have found fossils near the Colorado-New Mexico border that prove some dinosaurs survived the mass extinction that most researchers believe was caused by a meteor impact 65 million years ago. James Fassett, a scientist with the U.S. Geological Survey, says he has found evidence that a sizable population of ceratopsians and sauropods, a class of giant, dim-witted leaf-eaters such as the brachiosaurus, hung on for another 500,000 years in the [San Juan] basin. “There might even have been some T. rexes, based on some teeth we found” [Los Angeles Times], he said.
The bones of hadrosaurs, tyrannosaurs, anklyosaurs, and several other species were found together in a sandstone formation that dates to the Paleocene epoch—the time period after the so-called Cretaceous-Tertiary (K-T) extinction event, which is thought to have killed off the dinosaurs [National Geographic News]. To prove that the bones he found were indeed older than the extinction and eliminate the possibility that they had not simply been incorporated into newer rocks, Fassett points to his discovery of 34 bones from a single hadrosaur: If they had been washed away from their original location, they would almost certainly have been separated, not found together [Los Angeles Times].
He also investigated the rocks surrounding the bones and studied date indicators, such as their magnetic polarity. He said the evidence “independently indicate[s] that they do indeed post-date the extinction” [LiveScience]. He found that older rocks in the region contained different concentrations of rare metal elements than the dinosaur bones, suggesting that the bones did not originate in those samples of rock.
Hassett says there are several possible explanations for how a cluster of dinosaurs could have survived the fallout from the meteor impact, which formed a 112-mile-wide crater on Mexico’s Yucatan peninsula. Since the fossils found belonged to egg-laying dinosaurs, the worst effects of the asteroid may have passed by the time unborn eggs hatched, or the survivors of the collision may have been living elsewhere–perhaps far to the north–at the time it occurred. Driven south by the frigid weather unleashed by the asteroid collision, they could have made the San Juan Basin their last home [Los Angeles Times].
The new study, published in Palaeontologia Electronica, is not the first to challenge the theory of mass extinction, which has come under skepticism by some scientists who suspect other factors were involved, from increased volcanic activity to a changing climate [LiveScience], and the recent findings certainly won’t settle the controversy for good. “Every few years someone claims to have [found] Paleocene ‘surviving’ dinosaurs” [National Geographic News], said the Smithsonian Institution’s Hans-Dieter Sues.
Related Content:
80beats: New Study Casts Doubt on the Asteroid Strike Theory of Dino Extinction
80beats: Forget “The Asteroid”: Could Supervolcanoes Have Killed the Dinosaurs?
DISCOVER: Did an Asteroid Really Dust the Dinosaurs?
Image: Wikimedia
May 4th, 2009 at 5:21 pm
> To prove that the bones he found were indeed older than the extinction
Perhaps you mean “newer”.
May 4th, 2009 at 5:36 pm
This is a Science blog, yes? What is the benefit of using terms like “dim-witted” ?
May 4th, 2009 at 5:54 pm
She was quoting the LA Times when she used the term “dim-witted.” Maybe you should take it up with them.
May 5th, 2009 at 9:20 am
Finding ‘ Suggests Some Dinos Survived the Asteroid Cataclysm ‘
Of course they did !
There’s a couple of feathery ones eating breadcrumbs on my windowsill right now . . .
May 5th, 2009 at 11:17 am
Exactly, Eiron! A number of animals survived the cataclysm and roam the Earth today. The alligator, and I quote, has been described as a ‘living fossil from the age of reptiles, having survived on earth for 200 million years’. (US Fish and Wild Life site)
May 6th, 2009 at 12:50 am
@Mike . . . Maybe authors are responsible for the content they reproduce. Otherwise, given the trend, no one will be held accountable for misinformation.
May 6th, 2009 at 2:48 pm
Well it wasn’t really an age of reptiles. Most finds suggest a more bird like ancestry. They are pretty sure that raptors had feathers along with many other different dinosaurs.
May 6th, 2009 at 5:17 pm
Could a large meteor strike potentially have caused an increase in volcanic activity?
May 6th, 2009 at 5:45 pm
I remember reading that the volcanic activity in the Deccan Traps around the time of the K-T Boundary would have sent a great deal more “dust” into the atmosphere than the meteorite impact. Can anyone reading this back that up with some numbers?
May 6th, 2009 at 7:42 pm
Kyle C here are some numbers -> 163+5762168/43218-4321(687)451/84=6/549846352-468(76568)
May 7th, 2009 at 1:01 am
=P Go internet.
For some reason, none of those are zeros.
May 11th, 2009 at 8:32 pm
@John. Birds are theropod dinosaurs, yeah.