A rocky outcrop on the shore of Hudson Bay in northern Quebec contains the oldest known intact rocks on Earth, dated to at least 4.16 billion years ago — the only known surviving rock record from the Hadean eon, when Earth's first crust and oceans were taking shape.

A rocky outcrop on the shore of Hudson Bay in northern Quebec contains the oldest known intact rocks on Earth, dated to at least 4.16 billion years ago — the only known surviving rock record from the Hadean eon, when Earth's first crust and oceans were taking shape.

A low, weathered outcrop beside Hudson Bay holds a record that almost all the rest of Earth has erased. Rocks in the Nuvvuagittuq Greenstone Belt near Inukjuak, in northern Quebec’s Nunavik region, are at least 4.16 billion years old, according to two isotope clocks that independently placed them in the Hadean eon. The finding does not mean every stone at the site formed on one date. The researchers dated younger rock that intruded into the belt…