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Amid fields of soybeans just outside Eyreville on Virginia’s Eastern Shore, geologists are closing in on an ancient cataclysm.
Since September, an international team of scientists have been boring a 7,200-foot hole through the clay and silt that sits atop a 53-mile-wide crater buried below the Chesapeake Bay.
The farm is just off-center from where geologists say a 2-mile-wide, fiery space rock exploded more than 35 million years ago, creating an inverted sombrero-shaped crater that quickly filled with tons of water and debris.
“We’re moving along really well,” said Greg Gohn, the U.S. Geological Survey scientist leading the project.
The Chesapeake Bay impact crater is the largest in the United States and the sixth-largest in the world. As deep as the Grand Canyon, it sits below about 1,000 feet of rubble and sediment beneath the lower part of the Bay, its surrounding peninsulas and the inner continental shelf of the Atlantic Ocean.
Four-dozen scientists are working with technicians at the site in 12-hour shifts around the clock to take cores in 5– or 10-foot segments. They expect to reach the crater floor and unearth traces of the space rock. They also may find water trapped in the crater’s depths by the impact’s aftermath and perhaps descendants of the original microbes that floated in the waters off Virginia millions of years ago, said microbiologist Charles Cockell of Open University in the United Kingdom.
“The cores are really telling us the story of this crater,” said David Powars of the USGS, one of the crater’s co-discoverers.
In the rubble brought up by the drilling, scientists hope to find clues about the Earth’s primeval climate and where thirsty Tidewater residents can find drinkable water.
The impact sent a shockwave about 7 miles underground, melted rock, spewed debris, briefly exposed the sea floor and vaporized water. The deep gouge was then covered beneath a thick blanket of debris, rock, sediment and water. As this crater settled, it set the stage for Virginia’s baffling coastal groundwater system, with its pockets of salty groundwater.
Its legacy is well-known to Tidewater residents who try to drill for drinkable water and encounter pockets of brackish groundwater.
