Fragments of asteroid that killed dinosaurs may have been found


“To see a piece of criminal is just a strange experience.”

Fish fossils and Triceratops skin are on display during a presentation at the Goddard Space Flight Center in Greenbelt, MD, on Wednesday, April 6. Kenneth Chang/The New York Times

GREENBELT, MD — Ancient fragments of an impactor that killed dinosaurs have been discovered, scientists studying a North Dakota site say are the time capsule of the day of that disaster 66 million years ago.

Scientists estimate that the object that slammed Mexico’s Yucatan Peninsula today was about 6 miles wide, but the object’s identity remains a subject of debate, Was it an asteroid or comet? If it was an asteroid, what type was it – a solid metal one or a pile of rocks and dust held together by gravity?

“If you’re able to actually identify it, and we’re on the road to doing that, you can really say, ‘Wonderful, we know what it was,'” said Robert DePalma, a paleontologist who is leading the excavation of the site, said Wednesday during a talk at NASA’s Goddard Space Flight Center in Greenbelt.

A Goddard spokesman said a video of the conversation and subsequent discussion between DePalma and leading NASA scientists will be released online in a week or two. Many such discoveries will be discussed “Dinosaurs: The Final Day,” a BBC documentary narrated by David Attenborough, which will air in the UK this month. In the United States, the PBS program “Nova” will air a version of the documentary next month.

A new yorker Articles in 2019 The site in southwestern North Dakota named Tanis has been described as a wonderful land of fossils buried in the aftermath of the impact, some 2,000 miles away. there were many paleontologists Concerned but uncertain about the scope of DePalma’s claims, A Research Paper Published by DiPalma and his colleagues that year mostly describe the geological setting of the site, which was once located on a riverbank.

When the object hits Earth, creating a crater about 100 miles wide and about 20 miles deep, the molten rock shatters into the air and cools into a glass sphere, which is one of the typical calling cards of meteor impacts. is one. In a 2019 paper, DePalma and his colleagues describe how globules raining from the sky closed the gills of paddlefish and sturgeon, suffocating them.

The exterior of the impact spheres has been mineralized by millions of years of chemical reactions with water, usually. But in Tanis, some of them descended into the resin of the tree, which provided a protective circle of amber that engulfed them almost the same day as they were formed.

In the latest findings, which have not yet been published in a peer-reviewed scientific journal, DiPalma and his research colleagues focused on fragments of unmolten rock within the glass.

“All these little dirty nuggets in there, every single particle that’s being carried away by this beautiful clear glass is a piece of debris,” said DePalma, a graduate student at the University of Manchester in England and an assistant professor at Florida Atlantic University.

Finding the spheres surrounded by amber, he said, was the equivalent of sending someone back in time to the day of the impact, “collecting the sample, bottling it up and preserving it for scientists now.”

Most of the rock bits contained high levels of strontium and calcium – indications that they were part of the limestone layer where the meteor struck.

But the composition of the fragments within the two spheres was “extremely different,” DePalma said.

“They were not enriched with calcium and strontium as we would expect,” he said.

Instead they contained high levels of elements such as iron, chromium and nickel. That mineralogy points to the presence of an asteroid, and in particular a type known as carbonaceous chondrites.

“It’s just a strange experience to see a piece of the offender,” DePalma said.

Search supports a search Frank Kyte in 1998. reported by, geochemist at UCLA. Kayte said he found a fragment of the meteor in a core sample drilled in Hawaii, more than 5,000 miles from Chicxulub Crater. Kayte said about one-tenth of an inch came from the impact event, but other scientists were skeptical that any fragments of the meteor could have survived.

“It’s really in line with what Frank Kite told us years ago,” DePalma said.

In an email, Kyte said it was impossible to evaluate the claim without looking at the data. “Personally, I expect that if any meteorite material is in this ejecta, it will be extremely rare and vast amounts of other ejecta are unlikely to be found at this site,” he said. “But maybe they got lucky.”

DiPalma said that some bubbles are also visible in some of the spheres. Because the spheres do not appear to be torn, it is possible that they may have held fractions of air from 66 million years ago.

NASA Goddard Chief Scientist Jim Garvin said it would be fascinating to compare Tanis’ pieces Samples collected by NASA’s Osiris-Rex missionA spacecraft headed to Earth after a visit to a similar but smaller asteroid, Bennu.

State-of-the-art techniques used to study space rocks, such as Recently uncovered samples from the Apollo missions 50 years ago, can also be employed on tennis material. “They would work perfectly,” Garvin said.

In conversation, DiPalma also showed off other fossil finds, including a well-preserved leg of a dinosaur identified as the plant-eating Thessaurus. “This animal was preserved in such a way that you had these three-dimensional skin marks,” he said.

There is no indication that the dinosaur was killed by a predator or disease. This suggests that the dinosaur may have died on the day of the meteor impact, probably by drowning in the flood waters that engulfed Tanis.

“It’s like a dinosaur CSI,” DePalma said. “Now, as a scientist, I’m not going to say, ‘Yes, 100%, we have an animal that died in impact surge,'” he said. “Is it compatible? Yes.”

Neil Landmann, curator emeritus in the division of paleontology at the American Museum of Natural History in New York, visited Tanis in 2019. They spotted one of the paddlefish fossils with globules in their gills and are convinced the site did indeed capture the day. The Holocaust and its immediate aftermath. “It’s the real deal,” he said.

DiPalma also showed images of the embryo of a pterosaur, a flying reptile that lived in the time of the dinosaurs. Studies indicated that the egg was as soft as that of modern-day geckos, and the dimensions of the bones and feathers of the embryo contained high levels of calcium. support existing research Reptiles may have been able to fly as soon as they incubate their eggs.

Steve Brussett, a paleontologist at the University of Edinburgh in Scotland who was a consultant to the BBC documentary, is also convinced that the fish died that day, but he is not yet sure whether dinosaurs and pterosaur eggs were also victims of the impact.

“I haven’t seen the slam-dunk evidence yet,” he said in an email. “It is a credible story, but has not yet been proven beyond a reasonable doubt in the peer-reviewed literature.”

But the pterosaur embryo nonetheless is “an amazing discovery,” he said. Though initially skeptical, he said that after seeing the pictures and other information, “I was blown away. To me, this may be the most important fossil of Tanis.”

This article is originally from . appeared in the new York Times,

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