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.

Two samarium-neodymium chronometers date a crosscutting intrusion in Quebec’s Nuvvuagittuq belt to the Hadean, setting a minimum age for its older host rocks. The post Rocks exposed along a remote stretch of Hudson Bay in northern Québec are at least 4.16 bil…