Earth's oldest rocks are over 4 billion years old

Earth formed about 4.6 billion years ago during the Hadean Eon—a period named after the Greek god of the underworld, reflecting the planet's intense early heat.

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By around 4.35 billion years ago, Earth may have cooled enough for the first crust to form and possibly for life to begin.

But the earliest chapter of our planet’s history remains largely mysterious. Rocks from the Hadean are extremely rare, leaving major gaps in our understanding of Earth’s formation and early evolution.

Our research team recently confirmed that the oldest known rocks on Earth are in northern Québec. Dating back more than four billion years, these rocks offer a rare glimpse into the planet’s ancient beginnings.

Remnants of the Hadean

The Hadean Eon lasted from Earth’s formation around 4.6 billion years ago to about 4.03 billion years ago. The oldest terrestrial materials ever dated are zircon crystals from Western Australia, some as old as 4.4 billion years. Though their original host rocks have eroded away, these tiny, durable minerals survived and have helped researchers piece together clues about early Earth.