Fragment of the asteroid that hit Earth and killed the dinosaurs may have been found in amber


It’s one of many amazing finds at a unique fossil site in North Dakota’s Hell Creek Formation that has preserved remnants of the cataclysmic moment that ended the age of the dinosaurs – a watershed moment in history. history of the planet.

Fossils unearthed fish there, which sucked up blasted debris during the impact, a turtle impaled with a stick and a leg that could have belonged to a dinosaur witnessing the impact of the asteroid.

DePalma, a postgraduate researcher at the University of Manchester in the UK and assistant professor in the geosciences department at Florida Atlantic University, began working at Tanis, as the fossil site is known, in 2012.

The dusty and exposed plains contrast sharply with what the site would have looked like at the end of the Cretaceous. At the time, the American Midwest was a swampy rainforest and a since-disappeared inland sea — known as the Western Interior Seaway — stretched from what is now the Gulf of Mexico to Canada.

Tanis is more than 2,000 miles from the Chicxulub impact crater left by the asteroid that struck off the coast of Mexico, but early discoveries made at the site convinced DePalma that it provides rare evidence of what led to the end of the age of the dinosaurs.

The site is home to thousands of well-preserved fish fossils that DePalma says were buried alive by displaced sediment as a massive body of water released by the asteroid impact moved up the inland seaway. Unlike tsunamis, which can take hours to reach earth after an earthquake at sea, these moving bodies of water, known as seiches, arose instantly after the huge asteroid crashed into the sea.

Certainly the fish died within an hour of the asteroid impact, not from the massive wildfires or nuclear winter that followed in the days and months that followed. monitoring. That’s because “impact spherules” – small chunks of molten rock hurled from the crater into space where they crystallized into a glass-like material – were found lodged in the fish’s gills. Analysis of fish fossils also revealed the impact of the asteroid in the spring.

“One piece of evidence after another started piling up and changing the story. It was a progression of clues like an investigation into Sherlock Holmes,” 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.”

The asteroid that doomed the dinosaurs hit in the spring

Many of the latest findings revealed in the documentary have not been published in scientific journals.

Michael Benton, professor of vertebrate paleontology at the University of Bristol, who acted as scientific adviser on the documentary, said that while it was a “matter of convention” that new scientific claims should Going through peer review before being revealed on TV, he and many other paleontologists have admitted that the fossil site truly represents the “last day” of the dinosaurs.

“Some experts have said ‘well, it could be the next day or a month before…but I prefer the simpler explanation, which is that it really documents the day the asteroid hit Mexico,’” a- he declared by e-mail.

A limb belonging to a Thescelosaurus, a small herbivorous dinosaur, as excavated from the Tanis fossil site in North Dakota.  The creature may have witnessed the asteroid that ended the age of the dinosaurs.

cosmic origin

Most of the glassy impact spherules that first revealed the fingerprints of the asteroid’s impact on DePalma are preserved as clay from geological processes over millions of years. However, DePalma and his collaborators also found spherules that landed in tree resin on the surface of a log on that fateful day and were preserved in amber.

“In this amber, we located a number of spherules which were essentially frozen in time, because, just like an insect in amber which is perfectly preserved, when these spherules entered the amber, the water did not couldn’t reach them. They never returned to the clay, and they’re perfectly preserved,” he said.

It’s “like getting a sample vial, going back in time and getting a sample from the impact site and then keeping it for science,” DePalma said. mentioned.

They were able to locate a number of small, unmelted rock fragments inside the glass spherules. Most of those tiny rock fragments were rich in calcium — likely limestone beneath the Yucatan Peninsula, DePalma said.

Shown here is amber with a potential piece of the asteroid inside.

“But two of them had extremely different composition. You had spikes of chromium and nickel and other elements that are only common in meteoritic material and these fragments based on our preliminary analysis… are almost certainly of cosmic origin.”

DePalma said they hoped to be able to confirm what the asteroid was made of and where it might have come from – efforts that caught NASA’s attention; DePalma presented his findings last month at the agency show Goddard Space Flight Center in Greenbelt, Maryland.

“This example of what could be a tiny little fragment, possibly micrograms, of the colliding asteroid – for a record of this to be preserved would be mind-boggling,” said Goddard chief scientist Jim Garvin. , who studied impact cratering. on Earth and Mars.

Amber Tomb Research spherules has not been published in a peer-reviewed journal. During peer review, scientists exchange rigorous feedback on each other’s work to ensure it stands up to scrutiny. DePalma said a peer review an article on the preliminary results would be published “in the coming months”.

dinosaur leg

An exceptionally preserved dinosaur leg with intact skin is another find from the Tanis site that features in the documentary, which first aired in the UK in April and has turned heads in the paleontological world.

The Thescelosaurus leg fossil after being excavated.

Very few fossils from the Cretaceous period have been found in the highest rocks of the geologic record, and it is possible that the lamina – which belongs to a Thescelosaurus, a small herbivorous dinosaur discovered by DePalma and his colleagues – could have died the same day the asteroid struck. The preservation of soft tissue such as skin suggests that his body did not have time to decompose before being buried in sediment.

“The only two scenarios supported here are that he died in the surge or he died right before (the asteroid impact) but so close in time that he really didn’t have time to break down. It’s not something that died years ago and then been reworked. That doesn’t happen with soft tissue like that.

A detailed analysis of the dinosaur’s leg bones could shed light on the conditions leading up to the impact.

The pterosaur egg discovered at Tanis is the only one found in North America.

Other interesting finds at the site include a fossilized pterosaur egg, the first found in North America. This shows that the eggs of the giant flying reptiles were soft like those of many reptiles today. A fossilized turtle with a wooden stick through its body is evidence that the creature was impaled during rising water triggered by the asteroid impact.

The work done at Tanis not only describes in breathtaking detail what happened on the day the asteroid hit, but it also provides insight in an event that caused a mass extinction and how that extinction unfolded afterward. 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 hazard on a global scale and the response of Earth biota to that hazard,” DePalma said. “It gives us… a crystal ball that goes back in time and allows us to apply it to today’s ecological and environmental crisis.”

“This is both surprising, but also a benefit for us. Because by studying this impact event in more detail, we can be better prepared to take care of our world at this time.”


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