Ancient Tsunami Traced to Asteroid Strike in Chesapeake Bay

MOORE COUNTY, N.C. — Roughly 35 million years ago, an asteroid slammed into what is now southeastern Virginia, unleashing a cataclysmic blast that sent shockwaves and tsunamis across the region. Now, researchers believe they’ve found physical evidence of that ancient tsunami — more than 240 miles away in the Sandhills of North Carolina.

The discovery came by chance. Nearly a decade ago, retired geologist Bob Ganis was invited to examine a trench on a property called Paint Hill Farm, where a pipeline was scheduled for construction. What he found puzzled him: a deep layer of sediment that didn’t match the known geology of the area.

Fossilized shark teeth helped date the layer to the late Eocene era — the same time as the massive impact in the Chesapeake Bay. Working with South Carolina geologist Ralph Willoughby and Old Dominion University’s Rich Whittecar, Ganis eventually identified the mysterious formation as a tsunami deposit.

The layers held compelling clues: charcoal, ash, fused rock, and a reddish clay known as plinthite, typically found in tropical seabeds. The clincher was the presence of iridium, a rare metal on Earth but common in asteroids — a signature of an extraterrestrial impact.

The Paint Hill formation offers the first physical evidence of the tsunami long believed to have followed the Chesapeake Bay impact, the largest known bolide strike in the U.S. Scientists had theorized that the force of the explosion — equivalent to thousands of nuclear bombs — would have triggered waves sweeping over the Blue Ridge Mountains and possibly across the Atlantic.

Their findings, published last month in the journal Southeastern Geology, mark a major step in confirming the far-reaching effects of the impact.

Paint Hill’s 300-acre property was recently acquired by the Nature Conservancy and is slated to become part of the Weymouth Woods Sandhills Nature Preserve. Researchers hope the site — with its ancient tsunami remnants — will become a focal point for scientific study and public education.

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