A team of geologists has discovered new evidence of an ancient asteroid impact and the resulting tsunami that occurred approximately 35 million years ago. This event unfolded near present-day Cape Charles, Virginia, where a small asteroid, traveling at around 40,000 miles per hour (64,373 kilometers per hour), crashed into the Atlantic Ocean, creating a significant impact crater buried under Chesapeake Bay.
This crater, which was first identified in 1990, is among the largest and best-preserved on Earth. The recent findings, detailed in the journal Southeastern Geology, indicate that the repercussions of the impact extended far beyond Virginia, with evidence found about 240 miles (386 kilometers) away in Moore County, North Carolina.
Geological Discoveries in North Carolina
The research team examined layers of rock in the Sandhills region of North Carolina, uncovering four distinct beds within a one-yard-thick layer. The first rock bed, approximately 17 inches (43 centimeters) thick, contained sandy clay rich in carbon glass and rock fragments. Additionally, the researchers detected 14 to 18 parts per billion of iridium, a chemical element often associated with meteorite impacts.
The second bed is about 3 inches (9 centimeters) thick and features silt and loosely bound quartz and carbon masses, alongside 2 to 6 parts per billion of iridium. The third layer, measuring 2 inches (6 centimeters), comprises a mixture of soil and seafloor fragments, while the fourth bed, approximately 6 inches (15 centimeters) thick, consists of coarse sand likely deposited by the tsunami that followed the impact.
Understanding the Impact’s Reach
When the asteroid struck, it generated a hypersonic shock wave, devastating plant and animal life across a vast area. The impact spread molten debris across regions stretching from Massachusetts to Barbados. Although scientists had long theorized that the collision triggered a massive tsunami, concrete evidence of its effects had been elusive.
The new study provides critical insights into the geological formations in North Carolina, linking them directly to the ancient asteroid impact. The first rock bed captures the immediate aftermath of the impact, filled with ejecta and carbon-rich debris. The second bed represents finer particles that were released as the debris plume dispersed, while the third bed documents the inland surge of seawater and sediment caused by the tsunami. Finally, the fourth bed indicates the subsequent refilling of the channel with clean sand and gravel.
These findings enhance our understanding of the Chesapeake Bay impact and its extensive consequences. The research illustrates how a single catastrophic event can reshape regions over millions of years, revealing the profound and lasting influence of ancient celestial occurrences on Earth’s geological history.
