CBC Radio’s Quicks & Quarks has a segment on a newly discovered fossil deposit that reveals many clues about the asteroid that took out the dinosaurs.  The site is a snapshot in time from a few hours after the impact.  The North Dakota site, nicknamed Tanis after the “lost” ancient Egyptian city, lies on private land within a tiny outcrop of the larger Hell Creek Formation.  There is a paper in the journal PNAS with all the amazing details.

In an astounding paleontological discovery, scientists have found direct evidence of animals dying in the hours following the impact that took out 75 per cent of the world’s species 66 million years ago in a rock outcrop in North Dakota.

“We’re so excited because the deposit that we have actually records a snapshot in time from within the first two hours after impact in very, very precise detail,” said Robert DePalma, an adjunct professor of geosciences at Florida Atlantic University and a PhD student at the University of Kansas.

Sixty-six million years ago, the site in what is now North Dakota was a lush terrestrial river valley, about 3,000 kilometres from where a 10-km wide asteroid or comet would strike the Yucatan penininsula.

Very shortly after the impact occurred, ejecta from the impact site rained down across the continent.

“We have particles of debris from the impact that are encapsulated by the deposit and were essentially dropped there while the deposit was forming,” said DePalma.