The massive three trillion gallon body of ancient salt water was found a half mile beneath the Chesapeake Bay. Scientists think a large asteroid created a crater where the water gathered and was preserved.
The seawater is thought to be between 100 and 150 million years old.
What’s even more stunning is, finding it was an accident. “This was a surprising site discovery,” Ward Sanford, a USGS hydrologist told the Washington Post. “This was not something we were looking for or even expected.”
The job was to map a crater beneath Cape Charles in Virginia.
Researchers say the underground lake is twice as salty as today’s oceans and likely came from the Atlantic.
At the time the Atlantic was a smaller ocean and had fluctuating salinity.
USGS hydrologist Ward Sanford said the size of the find could have turned up remarkable discoveries but there is an issue.
"While the distinct chemical signature of the Cretaceous-era ocean has been preserved, the remnants are scattered among countless cracks and pores.”
That means that despite a large sample there isn’t likely any ancient ocean life that would have survived.