South Africa's Kaapvaal craton and Western Australia's Pilbara craton are two of the best-preserved Archaean cratons on Earth. They have remarkably similar early Precambrian rocks. Identical radiometric ages of 3,470 ±2 mya have been got from rocky material thrown out by meteorite strikes. Similar structures from these two cratons have been dated between 3,500 to 2,700 mya. Similar greenstone belts are found at the edges of the Superior craton of Canada, and across the cratons of the former Gondwana and Laurasia continents.