TRENTON — How old are the oldest rocks in New Jersey and where are they located? Perhaps these questions haven’t exactly kept you up at night, but geologists have been wondering about them for a long time.
They know that the rocks in the mountains of North Jersey’s Highlands, remnants of ancient Appalachian Mountains that at one time rivaled the Rockies in might, are the oldest in New Jersey. They also accept that these rocks are about a billion years old. But they never knew precisely how old — until now.
The New Jersey Geological Survey, within the Department of Environmental Protection, teamed up with the U.S. Geological Survey and the Australian National University in a project funded by private grants to provide the most precise dating ever of New Jersey’s oldest rocks.