New evidence points to meteor forming the Chesapeake
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Evidence is mounting that the lower part of the Chesapeake Bay might have been formed by one of the world’s greatest natural disasters.
Scientists this week presented new evidence that a meteor slammed into the Earth 35 million years ago in that area, contributing to the formation of the Chesapeake.
“If it happened today, Washington would probably cease to exist,” said Christian Koeberl, one of a group of scientists who presented the new evidence Monday at a conference at the Smithsonian Institution.
Scientists believe the resulting explosion would have incinerated plants and animals living near shore before a massive wave, or tsunami, caused by the explosion hit the coast.
“Instant barbecue,” Koeberl, a geochemist at the University of Vienna, told The Washington Post.
For several years scientists have been gathering evidence that a 55-mile-wide meteor crater underlies the lower Chesapeake Bay and sea floor nearby.
C. Wylie Poag, of the U.S. Geological Survey, is leading studies of the Chesapeake crater and possible craters of the same age off the New Jersey coast and Siberia. Scientists believe the craters could all be from chunks of the same meteor.
Whatever hit the Chesapeake was at least a mile in diameter and hurtled through space at up to 45 miles per second before bashing into the Earth, according to scientists. When it hit, it almost certainly vaporized, melting part of the Earth’s crust, sending hot jets of gas and molten rock miles into the upper atmosphere.
Poag has mapped the crater which is centered on Cape Charles, Va., near the lower tip of the Delmarva Peninsula, and extends offshore. The zone in which rock was affected by the impact may extend as far as Washington and Richmond, Va.
Koeberl demonstrated rocks near the crater show deformations that happen when shock waves traveling through rock are powerful enough to alter its crystal structure.
No force in the normal course of the Earth’s history is powerful enough to produce such changes, he said. The rocks are therefore considered conclusive evidence of a meteor’s impact.
Scientists don’t believe the meteor was solely responsible for the Chesapeake’s formation.
“I think the impact did serve as a template for later development of the bay,” Poag said. “But it’s indirect.”
The Susquehanna, Rappahannock, Potomac, York and James rivers developed after the meteor hit and eventually converged toward a single spot along the coast. Poag speculates the low ground caused by the meteor crater drew the rivers toward that spot.
When at the end of the last ice age the ocean began rising, it flooded back into the rivers’ valleys, drowning their mouths and creating the Bay, scientists said.
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