It is one of the many amazing finds at a unique fossil site in the Hell Creek Formation in North Dakota that has preserved the remnants of the cataclysmic end of the dinosaur era – a turning point in the history of the planet.
The fossils found there include fish sucking up debris thrown during the blow, a turtle nailed to a stick and a leg that may have belonged to a dinosaur that saw the asteroid hit.
DePalma, a postgraduate researcher at the University of Manchester in the United Kingdom and an assistant professor in the Department of Geosciences at Florida Atlantic University, first started working at Tanis, known as the Fossil Field, in 2012.
Dusty, exposed plains are in stark contrast with what the site would look like at the end of the Cretaceous. 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 is now the Gulf of Mexico to Canada.
Tanis is more than 2,000 miles from the Chicxulub crater left by the asteroid that struck off the coast of Mexico, but initial discoveries at the site convinced DePalma that it provided 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 from displaced sediments as a huge amount of water released by the asteroid hit the inland sea. Unlike tsunamis, which can take hours to reach land after an earthquake at sea, these moving bodies of water, known as seiche, erupted instantly after the huge asteroid crashed into the sea.
“One piece after another began to be stacked and the story changed. It was an evolution of evidence like an investigation into Sherlock Holmes,” de Palma said.
“It gives a moment-by-moment story of what happens right after the collision and you end up getting such a rich resource for scientific research.”
Many of the latest discoveries made in the documentary have not been published in scientific journals.
Michael Benton, a professor of vertebrate paleontology at the University of Bristol who acted as scientific advisor on the documentary, said it was “conventional” that new scientific claims would have to be peer-reviewed before they could be televised. and many other paleontologists have accepted that the location of the fossils really represents the “last day” of the dinosaurs.
“Some experts said, ‘OK, it could be the next day or a month before… but I prefer the simplest explanation, which is that it actually records the day the asteroid struck Mexico,'” he said in an email.
“In this amber we have located a series of beads that were basically frozen in time, because, just like an amber insect that is perfectly preserved, when these beads got into the amber, the water could not reach them. “They never returned to clay, and they are perfectly preserved,” he said.
It’s “like taking a sample vial, running back in time and taking a sample from the impact area and then saving it for science,” DePalma he said.
They managed to locate a number of small unbroken rock fragments inside the glass spheres. Most of these tiny rock fragments were rich in calcium – most likely from limestone beneath the Yucatan Peninsula, DePalma said.
“But two of them were very different in composition. You had peaks in chromium and nickel and some other elements that are common only to meteorite material and these fragments based on our preliminary analysis … are almost certainly of cosmic origin.”
“This example of a tiny, perhaps microgram-like, fragment of an asteroid colliding – the fact that a record of it is being kept would be shocking,” said Jim Garvin, chief scientist at Goddard, which has studied impact craters. on Earth and on Mars.
Amber burial research spherules has not been published in a peer-reviewed journal. During peer review, scientists give rigorous feedback to each other on each other’s work to ensure that they respond to scrutiny. DePalma said a peer review The preliminary findings document will be published “in the coming months”.
A highly preserved dinosaur skin with discreet skin is another discovery from the Tanis site featured in the documentary, which premiered in the UK in April, and has caught the eye of the paleontological world.
Very few fossils from the Cretaceous period have been found on the upper rocks of the geological archive, and it is possible that the strand – belonging to a Thesselosaurus, a small herbivorous dinosaur discovered by DePalma and his colleagues – could have died the same day the asteroid struck. The preservation of soft tissues such as the skin indicates that his body did not have time to decompose before being buried in sediment.
“The only two supported scenarios here are that he died on the wave or that he died just before (the asteroid strike) but so close to the time that he really did not have time to disintegrate. This is not something that died years ago and this is not the case with such soft tissues. ”
Detailed analysis of the bones of the dinosaur’s legs could shed light on the conditions that prevailed before the impact.
Other interesting finds from the site include a fossilized pterosaur egg, the first to be found in North America. It shows that the eggs of giant flying reptiles were as soft as those of many reptiles today. A fossilized turtle with a wooden stick through its body is evidence that the creature was pinned during the water wave unleashed by the asteroid’s impact.
The work done at Tanis not only captures in astonishing detail what happened the day the asteroid struck, but also provides information in an event that caused a mass extinction and how that extinction then evolved. DePalma hopes this will provide a framework for thinking about the climate crisis today.
“The fossil record gives us a window into the details of a global threat and how Earth’s biological organisms are responding to that threat,” DePalma said. “It gives us … a crystal ball looking back in time and enables us to apply it to today’s ecological and environmental crisis.”
“This is both amazing and a benefit for us. Because by studying this impact event in more detail, we can be better prepared to take care of our world right now.”