Freshwater first appeared on Earth 4 billion years ago, ancient crystals hint

Zircon chemistry may push back the water cycle’s start by hundreds of millions of years

A satellite view of a rock formation in Australia where the earliest evidence of freshwater on Earth was found.

An analysis of ancient zircon crystals from the Jack Hills formation (shown in a satellite image) in Western Australia suggests freshwater was cycling on Earth hundreds of millions of years earlier than previously thought.

NASA/GSFC/METI/ERSDAC/JAROS, U.S./Japan ASTER Science Team

Earth may have had fresh, not just salty, water as soon as 600 million years after the planet formed — a mere blink of an eye in geologic time.