Rocks exposed along a remote stretch of Hudson Bay in northern Québec are at least 4.16 billion years old, new dual-isotope dating shows—the oldest surviving rocks yet identified and the only known intact fragment of Earth’s first 500 million years, the Hadean.

Rocks exposed along a remote stretch of Hudson Bay in northern Québec are at least 4.16 billion years old, new dual-isotope dating shows—the oldest surviving rocks yet identified and the only known intact fragment of Earth’s first 500 million years, the Hadean.

A low belt of dark, weathered rock beside Hudson Bay contains something almost absent from Earth: a physical sequence that may have survived from the planet’s first eon. The Nuvvuagittuq Greenstone Belt, near Inukjuak in northern Quebec’s Nunavik region, is made largely of metamorphosed volcanic rocks rich in magnesium and iron. A 2025 study in Science dated mafic intrusions inside the belt to the Hadean, about 4.16 billion years ago. Those intr…