Parts of the asteroid that killed the dinosaurs may have been found in the fossils

GREENBELT, Md. “Virgin pieces of the impact element that killed the dinosaurs have been found,” said scientists studying a site in North Dakota that is a time capsule from that fateful day 66 million years ago.

The site, which struck off the Yucatan Peninsula in present-day Mexico, was about six miles wide, scientists say, but the identification of the site remains a matter of debate. Was it an asteroid or a comet? If it was an asteroid, what kind was it – hard metal or a pile of rubble rocks and dust held together by gravity?

“If you can actually identify it and we’re about to do it, then you can actually say ‘Amazing, we know what it was,'” Robert DePalma, a paleontologist in charge of the site’s excavations, said in a conversation Wednesday. NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

A video of the conversation and the ensuing discussion between Mr DePalma and prominent NASA scientists will be released online in a week or two, a spokesman for Goddard said. Many of the same findings will be discussed in “Dinosaurs: The Last Day”, a BBC documentary by David Attenborough, which will be broadcast in the UK in April. In the United States, PBS’s Nova program will air a version of the documentary next month.

When the object hit the Earth, carving a crater about 100 miles wide and nearly 20 miles deep, the molten rock exploded in the air and cooled into spheres of glass, one of the hallmarks of meteor strikes. In a 2019 article, Mr. DePalma and his colleagues described how spherules falling from the sky clogged the gills of a paddle and sturgeon by suffocating them.

Usually the outer parts of the impact spheres have been mineralogically transformed by millions of years of chemical reactions with water. But in Tanis, some of them landed in wood resin, which provided a protective shell of amber, keeping them almost as virgin as the day they formed.

In recent findings, which have not yet been published in a peer-reviewed scientific journal, Mr. DePalma and his fellow researchers focused on pieces of unmelted rock in the cup.

“All these little dirty nuggets inside,” said Mr. DePalma, a graduate student at the University of Manchester in England and an associate professor at the Atlantic University of Florida. “Every speck that takes away from this beautiful clear glass is a piece of debris.”

Finding spheres wrapped in amber, he said, is the equivalent of sending someone back in time to the day of the strike, “collecting a sample, bottling and saving it for scientists right now.”

Most of the rock fragments contain high levels of strontium and calcium – indications that they were part of the limestone crust where the meteor hit.

But the composition of the fragments in two of the areas is “wildly different,” Mr DePalma said.

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

Instead, they contain higher levels of elements such as iron, chromium and nickel. This mineralogy indicates the presence of an asteroid, and in particular a species known as carbon chondrites.

“Seeing part of the culprit is just a bristling experience,” Mr DePalma said.

The find supports a discovery reported in 1998 by Frank Kite, a geochemist at the University of California, Los Angeles. Dr Kite said he found a fragment of the meteor in a sample of a core drilled off Hawaii more than 5,000 miles from Chixulub. Dr. Kite said this fragment, about a tenth of an inch in diameter, came from the impact, but other scientists were skeptical that some parts of the meteor could survive.

“This is actually in line with what Frank Kite told us years ago,” Mr DePalma said.

In an email, Dr. Kite said it was impossible to assess the claim without looking at the data. “Personally, I expect that if any meteorite material is in this discharge, it will be extremely rare and unlikely to be found in the vast volumes of other discharges in this place,” he said. “But maybe they were lucky.”

Mr DePalma said there also seemed to be some bubbles in some areas. Because the spheres do not appear cracked, they may be trapping air particles from 66 million years ago.

Jim Garvin, NASA’s chief scientist Goddard, said it would be fascinating to compare the fragments of Tanis with samples collected from NASA’s OSIRIS-REX mission, a spacecraft currently on its way to Earth after visiting Bennu. but a smaller asteroid.

State-of-the-art techniques used to study space rocks, such as recently discovered samples from Apollo missions 50 years ago, can also be used on Tanis’ material. “They will work perfectly,” said Dr. Garvin.

In the conversation, Mr DePalma also showed other fossil finds, including a well-preserved dinosaur leg identified as a plant-eating tecelosaurus. “This animal is preserved in such a way that you have these three-dimensional imprints on the skin,” 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 meteorite impact, possibly from drowning in the floods that flooded Tanis.

“It’s like a CSI dinosaur,” Mr DePalma said. “Now, as a scientist, I will not say, ‘Yes, 100 percent, we have an animal that died in a collision,'” he said. “Is it compatible?” Yes.”

Neil Landman, an honorary curator in the Department of Paleontology at the American Museum of Natural History in New York, visited Tanis in 2019. He saw one of the fossils of a paddle with gill spheres and is convinced that the place really captures the day of the cataclysm and its immediate consequences. “This is the real deal,” he said in a telephone interview.

Mr DePalma also showed images of a pterosaur embryo, a flying reptile that lived in the time of the dinosaurs. Studies show that the egg was as soft as modern geckos, and the high levels of calcium in the bones and the size of the embryo’s wings support existing research that reptiles may have been able to fly as soon as they hatched.

Steve Brusat, a paleontologist at the University of Edinburgh in Scotland who is a consultant for the BBC documentary, is also convinced that the fish died that day, but is still unsure that the dinosaur and pterosaur egg were also victims of impact.

“I have not yet seen evidence of a collision,” he said in an email. “This is a credible story, but it has not yet been proven beyond a reasonable doubt in the peer-reviewed literature.”

However, the pterosaur embryo is an “amazing discovery,” he said. Although initially skeptical, he added that after seeing photos and other information, “I was shocked. For me, this may be the most important fossil of Tanis.

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