��ֱ����

By Jonah Grinkewitz

When it comes to asteroids, most people think of the one that wiped out the dinosaurs 66 million years ago.

But about 35 million years ago, another asteroid (or possibly a comet) crashed into the Atlantic Ocean off the coast of Virginia. The resulting 53-mile-wide crater, located in the southern end of what is now the Chesapeake Bay, is the largest in the U.S. and the sixth largest in the world.

Scientists estimate the impact from the asteroid created a lateral blast that incinerated all life for hundreds of miles and triggered a massive tsunami that washed across much of modern-day Virginia, North Carolina and beyond.

Due to subsequent land erosion, evidence of this collision had only been found underwater near the crater site.

That is, until a team of scientists – including Rich Whittecar, Old ��ֱ���� University professor emeritus in the Department of Ocean and Earth Sciences – confirmed new evidence of the blast 240 miles away from where the asteroid landed.

It all started with a chance discovery in 2016 when a construction crew exposed an area of sediment in Moore County, North Carolina while digging a pipeline trench.

Bob Ganis, a retired consulting geologist from Southern Pines, North Carolina, happened to be studying the area and was confused by what he saw. 

“It didn’t make sense at every level of geology,” Ganis said.

The debris in the sediment was unlike any other sedimentary layers in the region, raising the question: what was it and how did it get there?

After bringing in other geologists to dig deeper – no pun intended – they confirmed three distinct layers of strata trapped in an ancient channel that could only have resulted from a massive impact, and the asteroid that struck off the coast of Virginia seemed the likely culprit.

“We were looking at a series of rapid events from a major impact,” Ganis said.

The bottom charcoal-rich, sandy layer in the channel contained crushed rock fragments, natural glass and high levels of iridium – a very rare earthly metal, but one much more common in asteroids. They concluded this was a blanket of ejected debris spread by the super-hot hypersonic shock wave from the impact blast. Shark fossils in the layers below dated to older than about 37.7 million years, meaning the ejecta layer in the channel could have been from the Chesapeake Bay asteroid collision 35 million years ago.

The layer above the ejecta, also rich in iridium, was a powdery material resulting from ash that blew into the atmosphere before falling back to earth.

Finally, the top sandy layer contained a mix of petrified wood, marine fossils, rolled-up sediment layers and iron-stained red, orange and yellow clay lumps called “plinthite.” The presence of these materials supports the idea that a tsunami ripped them up from the seabed and land and dropped them there.

As Ganis gathered his findings, he needed confirmation from other experts to confirm his hypothesis.

Enter Whittecar, who had studied plinthite in other areas of the world. 

“My job was to basically say, ‘Yep, that’s plinthite,’” Whittecar said. “That’s essentially how you piece together some of these multidisciplinary stories. One person can’t solve all these questions.”

The discovery is a rare and scientifically valuable find for geologists studying the down-range terrestrial effects of massive asteroid strikes.

Along with Ganis and Whittecar, the full team of scientists included Ralph Willoughby, retired geologist from the South Carolina Geological Survey; David Cicimurri, curator of Natural History at the South Carolina State Museum; and Steven Hageman, a professor at Appalachian State University.

Their findings on the discovery were in the peer-reviewed journal Southeastern Geology, Volume 55, 2025.