Incredible Treasure Trove Of Fossils Seems To Be From The DAY The Dino-Killing Asteroid Hit

0
227

A jumble of fossilized freshwater , trees and marine ammonites from appear to be from the day an asteroid created the giant Chicxulub crater, wiping out most of the living on the . The of land and , bundled into one site, appear to have been killed by a tsunami triggered by seismic waves radiating from the impact. Even though found at this site have not been definitively tied to the event, the site tell us more about the last extinction than any .

At the end of the Cretaceous Era, the middle of what is North was covered by the Western Interior Seaway. At Tanis, North Dakota, University of PhD student has found a mix of marine and terrestrial that appear to have been by cataclysmic waves from the nearby seaway. DePalma thinks these were not tsunamis arriving from the Gulf, but waves called seiches triggered in the seaway by seismic waves within minutes of impact.

In a paper to be published in Proceedings Of the National Academy of Science tomorrow, DePalma reports the gills of more than half the suspension-feeding fish buried at Tanis contain droplets of glass that are among the identifying features of large asteroid strikes. The heaped fossils are topped by a cap of material with the high concentration of iridium, the whose worldwide distribution alerted geologists to the an asteroid hit the at this . The site was apparently undisturbed by scavengers, as would normally happen with such a larger shallow burial, suggesting few survived.

David Burnham
Different species of fish are jumbled together at the Tanis site, all having been killed by the same sudden process. Robert DePalma

Together these findings create a of a of ejected material sweeping the continent less than two hours after the asteroid hit, followed by walls of least 10 meters (33 feet) high. The debris from both was buried under a heavier rain of asteroid-induced rock and ash from the consequent fires.

“Timing of the incoming ejecta spherules matched the calculated arrival times of seismic waves from the impact, suggesting that the impact could very well have triggered the surge,” DePalma said in a statement.

added: “The sedimentation happened so quickly everything is preserved in three dimensions – they’re not crushed… We have one fish that hit a tree and was broken in half.”

Several of the fish specimens found at Tanis, in the aptly named Hell Creek formation, are to be from previously unknown species.

metal
This fish provides an example of the stunning preservation of fish at the Tanis site, reflecting the lack of scavengers to consume them. Robert DePalma

For 30 years the theory an asteroid strike led to the extinction of the dinosaurs ( aside) has dominated the imagination and convinced most scientists. , a smaller group of geologists and paleontologists attribute the extinction to enormous volcanic eruptions in . Certainly, these transformed the ’s over hundreds of thousands of years either of the asteroid strike, and may have been of even more planetary significance.

Timing is key to this dispute. Volcano advocates argue the absence of dinosaur fossils from rocks laid down immediately the asteroid debris indicates they were already gone by then. This is why DePalma’s claim has hit the paleontological world with the metaphorical force of the asteroid itself.

The same site has produced a Triceratops and hadrosaur. Neither’s has yet been definitively tied to the impact, but the authors argue their presence in rocks of similar shows these species, if not the individuals, were alive when the asteroid hit.

DePalma is fully aware of the significance of his claim “As beings, we descended from a lineage that literally survived in the ashes of what was once the glorious kingdom of the dinosaurs,” he said. “And we’re the only species on that has ever been capable of from such an event to the benefit of ourselves and every other organism in our world.”

National Academy of Science
A microkystite produced in the ejecta plume from the crater that fell at Tanis as seen under an electronmicroscope. Robert DePalma

 



Related posts