Largest craton

Cratons are large parts of continental crust that are stable and that have remained relatively unmodified by plate tectonics since the end of the Precambrian era, 542 million years ago. They are normally located in the interior of continents and contain some of the oldest rocks on Earth. The North American craton is the largest, covering around 70% of the continent. It was formed around two billion years ago by the collision of several smaller microcontinents.