Jack Hills Zircons Reveal Earth’s Early Crust and Liquid Water
The Jack Hills in Western Australia contain zircon grains dating to 4.4 billion years ago, making them the oldest known rocks on Earth. These minerals, found in 3-billion-year-old sandstone, provide direct evidence of the planet's first crust and indicate the presence of surface water shortly after Earth formed, suggesting early conditions were cooler and potentially habitable.