3.1 billion-year-old rocks in Australia reveal a forgotten chapter of Earth’s water cycle

In the 45°C heat of the midday April sun, I swing my sledgehammer into the terracotta-varnished lobes of pillow basalt overlooking a sparse, almost Martian landscape.

Up close, the rock is freckled with small spheres or varioles, a texture that forms in wet magmas. It’s hard to fathom that this lava cooled when Earth was young, and has barely changed since.

Western Australia’s Pilbara Craton is probably the last place you’d expect to learn anything about the role water played in shaping our planet. It’s one…

© La Conversation - mardi 7 juillet 2026