Shards of Asteroid That Killed the Dinosaurs May Have Been Found in Fossil Site

The New York Times reports: Pristine slivers of the impactor that killed the dinosaurs have been discovered, said scientists studying a North Dakota site that is a time capsule of that calamitous day 66 million years ago... "If you're able to actually identify it, and we're on the road to doing that, then you can actually say, 'Amazing, we know what it was,'" Robert DePalma, a paleontologist spearheading the excavation of the site, said Wednesday during a talk at the NASA Goddard Space Flight Center in Greenbelt.... A New Yorker article in 2019 described the site in southwestern North Dakota, named Tanis, as a wonderland of fossils buried in the aftermath of the impact some 2,000 miles away. Many paleontologists were intrigued but uncertain about the scope of DePalma's claims; a research paper published that year by DePalma and his collaborators mostly described the geological setting of the site, which once lay along the banks of a river. When the object hit Earth, carving a crater about 100 miles wide and nearly 20 miles deep, molten rock splashed into the air and cooled into spherules of glass, one of the distinct calling cards of meteor impacts. In the 2019 paper, DePalma and his colleagues described how spherules raining down from the sky clogged the gills of paddlefish and sturgeon, suffocating them. Usually the outsides of impact spherules have been mineralogically transformed by millions of years of chemical reactions with water. But 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.... Finding amber-encased spherules, he said, was the equivalent of sending someone back in time to the day of the impact, "collecting a sample, bottling it up and preserving it for scientists right now...." DePalma said there also appear to be some bubbles within some of the spherules. Because the spherules do not look to be cracked, it's possible that they could hold bits of air from 66 million years ago. In 1998, UCLA geochemist Frank Kyte claimed he'd found a fragment of that meteor in a core sample drilled off Hawaii, the article points out, "but other scientists were skeptical that any bits of the meteor could have survived." But now DePalma tells the Times that this North Dakota discovery "actually falls in line with what Frank Kyte was telling us years ago."

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