Apr 09, 2022 I Paul Seaburn

A Fossilized Leg and an Asteroid Chunk from the Day the Dinosaurs Died May Have Been Found

I can't remember if I cried

When I saw the asteroid collide

But something touched me deep inside

The day the dinos died

    (Chicxulub Pie – with apologies to Don McLean)

There is much disagreement amongst scientists as to what caused the mass extinction of the dinosaurs around 66 million years ago, but an asteroid or comet crashing off the coast of what is now Mexico probably gets the most votes. If dinosaur fossils could talk, a leg discovered in what is now North Dakota would tell us the exact day that asteroid hit – paleontologists believe the Thescelosaurus it came from was killed by the impact … and a tiny rock fragment found with it may be from the Chicxulub asteroid itself.

Did you hear something?

"An object the size of Mount Everest hit the Earth and that was the end of the Cretaceous - and that's an extraordinary thing to happen."

In a new BBC documentary, “Dinosaurs: The Final Day with Sir David Attenborough,” Attenborough reveals new findings from the Tanis fossil site in southwestern North Dakota – called the “dinosaur graveyard” because of the number of well-preserved fossils found there from the time immediately after the Chicxulub event. On the day before the event, this was most likely a plain crossed by rivers and streams at the northern end of a large body of water known as the Western Interior Seaway which roughly cut today’s North America into tow land masses. When the asteroid hit the Earth at a steep angle one spring day, it pushed rocks into the atmosphere, created earthquakes and caused waves at least 10 meters (33 feet) high that flooded Tanis.

“We've got so many details with this site that tell us what happened moment by moment, it's almost like watching it play out in the movies. You look at the rock column, you look at the fossils there, and it brings you back to that day,"

Robert DePalma, the University of Manchester graduate student who leads the Tanis dig, told the BBC what it’s like peeling through the layers at the site, but Sir David Attenborough had the best comment about the discovery of the leg of the thescelosaurus, a small bipedal herbivore dinosaur:

“That is an impossible fossil.”

Charles W. Gilmore's 1915 restoration of a Thescelosaurus (public domain)

Why ‘impossible.? Professor Paul Barrett at the Natural History Museum in London told The Daily Mail the name Thescelosaurus means “wonderful lizard” and this leg is wonderfully impossible because it has preserved skin which shows they were very scaly like modern lizards rather than feathered like their carnivorous contemporaries. The leg looks healthy and appears to have been preserved immediately – no signs of scavenging -- after being ripped off of the Thescelosaurus, which probably died immediately. While it’s impossible to say with utmost certainty that it happened on the day of the Chicxulub impact event, another piece of evidence helps. The fossils of sturgeon and paddlefish at the site have small particles stuck in their gills which they breathed in with their last breaths. While some are spherules of molten rock kicked out from the impact, others were chemically analyzed them at the Diamond X-ray synchrotron near Oxford by Professor Phil Manning, who is DePalma's PhD supervisor at Manchester, and showed something amazing.

"We were able to pull apart the chemistry and identify the composition of that material. All the evidence, all of the chemical data, from that study suggests strongly that we're looking at a piece of the impactor; of the asteroid that ended it for the dinosaurs."

Is it time to drop the fossilized mic and declare the discovery of a piece of the Chicxulub asteroid and the leg of a dinosaur it killed on the day it arrived? These researchers would love to do that and are continuing their analysis.

Will this mean some dinosaur movies have to be revised? Chris Pratt … call your agent!

Paul Seaburn

Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

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