Witwatersrand Gold Fields: Geology, Genesis, and Exploration
The mineralogy of the Witwatersrand reefs is dominated by pyrite with lesser pyrrhotite and arsenopyrite, widespread nickel and cobalt sulfarsenides, and low base metal sulfides. A distinctive mineral assemblage of pyrophyllite-chloritoid-muscovite-chlorite-quartz-rutile-pyrite is found in and around the reef package in all gold fields.
4. Geological setting and mineralisation
The Witwatersrand Basin comprises a 6,000 metre thick sequence called the Witwatersrand Supergroup, which consists of predominantly detrital sedimentary rocks interspersed sporadically with auriferous and uraniferous quartz pebble conglomerates, termed reefs, especially in the upper parts of the succession classified as the Central …
Hydrothermal Replacement Model for Witwatersrand Gold
Hydrothermal and placer origins for Witwatersrand gold have been debated ever since the discovery in 1886 of the Central Rand goldfield in South Africa. The hydrothermal model is supported by recent findings of a complex postdepositional history for the Witwatersrand Supergroup, including extensive deformation, greenschist facies …
Witwatersrand Gold Fields: Geology, Genesis, and Exploration
The Witwatersrand gold fields of South Africa account for more than a third of the world's total gold production since mining started there in 1886: 48,000 t Au. These gold fields dominated production throughout the twentieth century, but production peaked at 1,000 t in 1970 and has steadily declined since that time.
Witwatersrand System | geology | Britannica
Witwatersrand System, major division of Precambrian rocks in South Africa (the Precambrian began about 3.8 billion years ago and ended 540 million years ago). The Witwatersrand rocks overlie rocks of the Dominion Reef System, underlie those of the Ventersdorp System, and occur in an east-west band from Randfontein to Springs and …
Witwatersrand Basin
The Witwatersrand basin on South Africa's Kaapvaal craton is one of the best known of Archean sedimentary basins, and it contains some of the largest gold reserves in the world, accounting for more than 55 percent of all the gold ever mined. Sediments in the basin include a lower flysch-type sequence, and an upper molassic …
Witwatersrand | mountain ridge, South Africa | Britannica
Witwatersrand, also called The Rand, ridge of gold-bearing rock mostly in Gauteng province, South Africa. Its name means "Ridge of White Waters." The highland, which forms the watershed between the Vaal and Limpopo rivers, is about 62 miles (100 km) long and 23 miles (37 km) wide; its average elevation is about 5,600 feet (1,700 metres). Its rich gold …