FAU Professors' Research Gives Snapshot of World Millions of Years Ago
Robert DePalma and Dr. Anton Oleinik teach paleontology at Florida Atlantic University in Boca Raton. In their spare time, they're making earth-shattering discoveries in North Dakota about the day 66 million years ago when an asteroid shattered the Earth, slamming into what is now the Yucatan Peninsula of Mexico.
"You had this stable system, the dinosaurs, that had been there for millions and millions and millions of years, all brought to their knees by this," said DePalma, who is a doctoral student at the University of Kansas.
"The giant impact set up a scene for mass extinction," Oleinik explained. "The aftermath effects put the Earth first into darkness and then the plants die, it essentially took some time.
DePalma has spent seven years working at the site in the badlands of North Dakota called Tanis. He is the lead author of a recently published, peer-reviewed paper which claims the Tanis site shows the actual day when the global apocalypse started, the very hours after the impact which wiped out 75% of life on the planet.
"In geology, you basically see time represented in hundreds of thousands to millions of years in a single rock layer, you're not going to see a moment in time very often, at this site you have a moment in time recorded," DePalma said.
The asteroid was the size of Mount Everest. Its impact, DePalma says, "rang the planet like a dinner bell" and sent shock waves everywhere.
The North Dakota site is thousands of miles from the impact zone, yet it features remarkably preserved fish, plants, and other wildlife, including some dinosaur bones, tossed together like a salad by the seismic surge.
"We know that this is related to the actual Chicxulub impact that brought about the extinction because it has the geochemical fingerprint of that impact event," DePalma said, explaining one of several ways the 11 authors of the paper came to the conclusion that the layer of fossils they found was connected to the asteroid impact.
Another tell-tale clue is the overwhelming presence of tiny glass balls called ejecta spheriles, or tektites.
The asteroid melted upon impact, spewing molten glass into the atmosphere which rained down as tektites. DePalma's team found them embedded in the gills of fossil fish from the site, which means the fish breathed them in before they died.
They also found the tektites embedded in amber from trees that were knocked down in the seismic waves.
DePalma says being part of this discovery has had a profound impact on his view of history.
"We basically, as mammals, got our beginnings as a result of the dinosaurs being cleared off the playing field so this asteroid making that vacancy in the ecology was what enabled mammals to rise and diversify and become what we are today," DePalma said.
There is much more work to do. Now that their initial paper has been published, other teams of scientists are working at the site, and all their findings can be compared and data shared with paleontologists around the globe.
The team's work shines a light on what happened one extremely significant day 66 million years ago, and reminds everyone how fragile life on Earth can be.