It’s one of several astounding finds at a unique fossil site in the Hell Creek Formation in North Dakota that has preserved remnants of the cataclysmic moment that ended the dinosaur era — a turning point in the history of the planet.
The fossils unearthed there include fish that sucked in debris blasted out during the strike, a turtle impaled with a stick and a leg that might have belonged to a dinosaur that witnessed the asteroid strike.
DePalma, a postgraduate researcher at the University of Manchester in the United Kingdom and adjunct professor for the Florida Atlantic University’s geosciences department, first started working at Tanis, as the fossil site is known, in 2012.
The dusty, exposed plains starkly contrast with what the site would have looked like at the end of the Cretaceous Period. Back then, the American Midwest was a swampy rainforest, and an inland sea that has since disappeared — known as the Western Interior Seaway — ran all the way from what’s now the Gulf of Mexico to Canada.
Tanis is more than 2,000 miles away from the Chicxulub impact crater left by the asteroid that struck off the coast of Mexico, but initial discoveries made at the site convinced DePalma that it provides rare evidence of what led to the end of the dinosaur era.
The site is home to thousands of well-preserved fish fossils that DePalma believed were buried alive by sediment displaced as a massive body of water unleashed by the asteroid strike moved up the interior seaway. Unlike tsunamis, which can take hours to reach land after an earthquake at sea, these moving water bodies, known as a seiche, surged out instantaneously after the massive asteroid crashed into the sea.
“One piece of evidence after another started stacking up and changing the story. It was a progression of clues like a Sherlock Holmes investigation,” DePalma said.
“It gives a moment by moment story of what happens right after impact and you end up getting such a rich resource for scientific investigation.”
Many of the latest discoveries revealed in the documentary haven’t been been published in scientific journals.
Michael Benton, a professor of vertebrate paleontology at the University of Bristol, who acted as a scientific adviser on the documentary, said while it was a “matter of convention” that new scientific claims should go through peer review before being revealed on television, he and many other paleontologists accepted that the fossil site really does represent the dinosaurs’ “last day.”
“Some experts have said ‘well, it might be the day after or a month before … but I prefer the simplest explanation, which is that it really does document the day the asteroid hit in Mexico,” he said via email.
Cosmic origin
“In that amber we’ve located a number of spherules that were basically frozen in time, because, just like an insect in amber which is perfectly preserved, when these spherules entered the amber, water couldn’t get to them. They never turned to clay, and they’re perfectly preserved,” he said.
It’s “like getting a sample vial, running back in time and getting a sample from the impact site and then saving it for science,” DePalma said.
They were able…
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