The Richest Gold Province on Earth Worth $13 Trillion

The Witwatersrand Basin in South Africa is the richest gold province on Earth, producing around 48,000 tonnes of gold and reshaping the history of mining and geology. Unlike most goldfields defined by narrow quartz veins, the Witwatersrand’s famous “reefs” are ancient river gravels that were buried, metamorphosed, and later modified by hot fluids, thrust faulting, and even a massive asteroid impact at Vredefort. This post unpacks how Archaean rivers, regional metamorphism, structural deformation, and hydrothermal processes combined to create the world’s greatest gold deposit, why the placer versus hydrothermal debate still matters, and what the Witwatersrand tells us about early Earth, ancient atmospheres, and ore formation.