Some parts of the crust are incredibly old. The oldest piece found on Earth is the Acasta Gneiss in Canada—4.03 billion years old. That’s almost as old as the planet itself. It’s like finding a wrinkle on a newborn baby.
These ancient crustal scraps are called cratons. They’re the boring, stable bits that haven’t been squished or melted in eons. Imagine the quietest, most reliable friend you have—that’s a craton. Good ol’ Fred over there, just chilling for 4 billion years.
