In the Jersey suburbs, a search for rocks to help fight climate change

In early spring, George Okoko was perched on a ledge 15 feet up a crumbly cliff, trying to whack off a basketball-size piece of rock with a hammer and chisel. The locale was suburban Berkeley Heights, N.J. The rock was basalt, a common product of volcanism. This batch formed some 200 million years ago, during vast eruptions that occurred as Europe slowly tore away from North America, creating a chasm that became the Atlantic Ocean.