Scientists studying a North Dakota site that is a time capsule of that calamitous day 66 million years ago say they have found fragments of the impactor that killed the dinosaurs.
Scientists estimate that the object that slammed off the Yucatn Peninsula of Mexico was about six miles wide, but the identification of the object has remained a subject of debate. Was it a comet or an asteroid? If it was an asteroid, what kind was it, a solid metallic one or a rubble pile of rocks and dust?
If you can actually identify it, then you can say that we know what it was.
A video of the talk and a subsequent discussion between Mr. DePalma and prominent NASA scientists will be released online in a week or two. The final day of dinosaurs will be the subject of a documentary narrated by David Attenborough that will air in Britain in April. The PBS program will broadcast a version of the documentary next month.
It is an approximation.
About the shoreline.
65 million years ago.
It is an approximation.
About the shoreline.
65 million years ago.
When the object hit Earth, it carved a crater about 100 miles wide and nearly 20 miles deep, and molten rock splashed into the air and cooled into spherules of glass. In the paper, Mr. DePalma and his colleagues described how spherules rained down from the sky, suffocating paddlefish and sturgeon.
Millions of years of chemical reactions with water have transformed the outsides of impact spherules. At Tanis, some of them landed in tree resin, which provided a protective enclosure of amber, keeping them almost as pristine as the day they formed.
The latest findings, which have not yet been published in a peer-reviewed scientific journal, focused on bits of unmelted rock within the glass.
Mr. DePalma is a graduate student at the University of Manchester in England and an instructor at Florida Atlantic University.
He said that finding amber-encased spherules was like sending someone back in time to the day of the impact.
Most of the rock bits have high levels of strontium and calcium, which are signs that they were part of the limestone crust.
Mr. DePalma said that the composition of fragments within two of the spherules were vastly different.
He said that they were not enriched with calcium and strontium as expected.
They had higher levels of elements like iron and nickel. The type of carbonaceous chondrites found in that mineralogy is indicative of the presence of an asteroid.
Mr. DePalma said that seeing a piece of the culprit is just a goose-bumpy experience.
The finding supports a discovery made in 1998 by Frank Kyte. A fragment of a meteorite was found in a core sample drilled off Hawaii, more than 5,000 miles away from Chicxulub. Dr. Kyte said that the fragment came from the impact event, but other scientists were skeptical that any bits of the meteorite could have survived.
Mr. DePalma said it falls in line with what Frank Kyte was telling us years ago.
It was impossible to evaluate the claim without looking at the data, according to Dr. Kyte.
Mr. DePalma said there may be bubbles in some of the spherules. It is possible that the spherules could hold bits of air from 66 million years ago.
It would be fascinating to compare the Tanis fragments with samples collected by NASA's OSIRIS-REX mission, which is currently en route to Earth after a visit to Bennu, a similar but smaller asteroid.
State-of-the-art techniques being used to study space rocks, such as the recently opened samples from the Apollo missions 50 years ago, could also be employed on the Tanis material.
The leg of a plant-eating Thescelosaurus was shown in the talk by Mr. DePalma.
There are no signs that the dinosaur was killed by a predator. It's possible that the dinosaur died on the day of the meteorite impact because of the flooding in Tanis.
Mr. DePalma said that it was like a dinosaur. Yes.
Neil Landman is the curator of paleontology at the American Museum of Natural History in New York. He saw a paddlefish fossil with spherules in its gills and is convinced that the site captures the day of the cataclysm.
The embryo of a flying reptile that lived during the time of the dinosaurs was shown by Mr. DePalma. Studies show that the egg was soft like modern-day geckos, and that the embryo had high levels of calcium in it's bones.
Steve Brusatte, a paleontologist at the University of Edinburgh in Scotland who served as a consultant for the documentary, believes that the fish died that day, but he is not sure if the dinosaur and the pterosaur egg were also killed.
He said in an email that he hadn't seen the evidence yet.
He said that the pterosaur embryo is an amazing discovery. He said that after seeing photos and other information, he was blown away. This may be the most important fossil from Tanis.
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