News Earth 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 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 Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Carolyn Gramling June 3, 2024 at 11:00 am 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.