Earth’s Oldest-Known Rocks:
A volcanic rock belt in Quebec’s (Canada) Nuvvuagittuq Greenstone Belt, dated to be 4.16 billion years old, has been identified as the oldest-known rock on Earth, originating from the Hadean eon (4.5–4.03 billion years ago), when Earth itself was formed about 4.6 billion years ago.The rocks are metamorphosed volcanic basalt, formed when magma solidified underground, and provide clues about Earth’s early crust, primordial oceans, and the environment where life may have begun. Two radioactive dating methods (samarium-neodymium decay) confirmed the age, making them the oldest-known intact rocks. Zircon crystals from Australia (4.4 billion years old) remain the oldest mineral fragments, but the Quebec rocks are the oldest intact geological formations. The Hadean eon (4.5–4.03 billion years ago) was previously thought to be a molten hellscape (extremely harsh, hostile, or dangerous to life), but evidence suggests a cooling crust, shallow oceans, and an early atmosphere.
