Witwatersrand system, major division of precambrian rocks in south africa the precambrian began about 3. Data repository items are published exactly as the author provided them to the journal. December 20 economy report south africa hannsseidelfoundation johannesburg office p. The gold in this basin occurs in the coarse grained conglomerates forming the upper portions of the witwatersrand supergroup that hosts roughly.
Health risk assessment of heavy metals in soils from witwatersrand gold mining basin, south africa. The theory of an originally detrital origin of the witwaters rand deposits is now well supported by. At the bottom of the worlds deepest gold mine, there is a 30inch seam of gold called the ventersdorp contact reef. Pdf health risk assessment of heavy metals in soils from. Understanding the groundwater dynamics is very important for strategic management of the water resource as urbanization and population growth put south africas current water supply under tremendous stress. Complex and emerging technologies to a manage the risk of. The witwatersrand basin and its gold deposits springerlink. The witwatersrand basin near the centre of the kaapvaal craton fig. Neoarchaean tectonic history of the witwatersrand basin and ventersdorp supergroup. The archean metasedimentary succession of the witwatersrand basin, south africa, hosts the largest au deposit in the world. The clastic sediments were derived from a mountainous source to the northnortheast of the basin button, 1986. The depositional facies grade from braided fluvial arkoses, through tidal flat sediments to mature sandy shelf deposits that consist primarily of shales and carbonate shales. Gly 163 earth history witwatersrand and pongola supergroups nils lenhardt earth history. At a first glance, the witwatersrand basin, the largest known gold resource on our planet, is not automatically related to ocean research.
Discover witwatersrand basin in hartbeespoort, south africa. Some materi als associated with the witwatersrand gold give ages older than the host conglomerates whereas others give younger ages. A major portion of this production is mined at depths exceeding 2500 m and deepest levels of mining are at. Witwatersrand basin, johannesburg, south africa outcome worlds largest gold rush ever led to the eventual boer defeat in the second boer war 18991902, the loss of boer autonomy and selfgovernment, and total british rule in south africa. Neoarchaean tectonic history of the witwatersrand basin. Geological framework and mineralization processes laurence j. Neoarchaean tectonic history of the witwatersrand basin and. It holds the worlds largest known gold reserves and has produced over 1. The witwatersrand basin in south africa hosts the largest known gold repository on earth but how was it formed.
Development of the witwatersrand basin, south africa geological. Metal distribution in pyrobitumen of the carbon leader. The fossil gold placers of the witwatersrand pdf paperity. The following are the supplementary data related to this article.
Witwatersrand basin and the platinumbearing reefs of the bushveld complex. Also known as aka it looks like we dont have any akas for this title yet. Witwatersrand mining basin the witwatersrand has been mined for more than a century. For further information about any data repository item, please contact the author. Scientists were able to figure out how parts of the earths largest gold deposits. The gold mines in this area are possibly the deepest mines in the world mining operations at 3600 m and exploration coredrilling up to 4600m. Driefontein no 3a and old north complex no 3 tailings dams. With our present knowledge we perceive the paleowitwatersrand as a basin surrounded by mountains of moderate height which were geologically. Gold mineralization is mostly concentrated in conglomerate horizons, or reefs, and is tightly associated with pyrite. The region hosts one of the worlds largest gold and uranium mining basins having more than 120 mines.
However, if the witwatersrand basin was formed significantly prior to 2 700 ma ago, it may be related to tectonism associated with the implacement. Pdf the worlds greatest deposit of gold is hosted by the archaean witwatersrand sedimentary basin, situated in the central portion of the. Map of the witwatersrand basin showing mining areas from which shales were collected for this study and stratigraphic column of the witwatersrand succession showing the horizons of sampled shales. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a pdf plugin installed and enabled in your browser. Witwatersrand basin, which contains nearly half the worlds gold, covers an area the size of west virginia in the northeastern part of south africa. Thus, the vredefort area formed a subbasin within the. The current concepts concerning the genesis of the unique orebearing reefs of the witwatersrand basin and its gold resource potential are considered.
Geological setting university of the witwatersrand. These dates only imply that 50 ma 7 0, and hence are. The witwatersrand basin is approximatly 350 km long and 200 km wide. Pdf evaluating the structural character and tectonic history of the. Witwatersrand basin moved independently from each other but followed the regional, nsdirected compressional regime fig. The witwatersrand basin is a large hinterland basin of archaean age. Sediments in the basin include a lower flyschtype sequence and an upper molassic facies, both of which contain abundant silicic volcanic detritus. Box 41451 craighall 2024 johannesburg south africa 3 phone.
The witwatersrand rocks overlie rocks of the dominion reef system, underlie those of the ventersdorp system, and occur in an eastwest band from randfontein to springs and from the vaal river in the region of. The results of microscopic examination of ore from the black, ventersdorp contact, carbon leader, and vaal reefs, as well as of thermobarometric study of quartz, are presented. The basin straddles the old provinces of transvaal and the orange free state. The witwatersrand basin project wbp comprises two historic mining centres known as the durban roodepoort deep and the rand leases on the northern edge of the witwatersrand basin in the central rand goldfield immediately southwest of the city of johannesburg figure 1.
Development of the witwatersrand basin, south africa. Firstorder scale structures in the west wits line and west rand goldfields of the witwatersrand basin south. Mininginduced seismicity and its hazardous manifestation, rockbursting, were encountered in the first decade of the 20th century when gold mines reached a depth of several hundred feet below the outcrop, forming extensive excavations supported solely by small reef. A contribution to recent debate concerning epigenetic. The origin of the gold mineralization in the witwaterstrand basin of south africathe largest known gold provincehas been controversial for decades, with arguments favouring detrital1,2. Michael meyer i department of geology, university of the witwatersrand, private bag 3, wits 2050, south africa received 19 december 1994. Files are available under licenses specified on their description page. Its estimated that half of the worlds gold was mined from south africas golden arc.
Durrheim a,c a school of geosciences, university of the witwatersrand johannesburg, pbag 3, wits, 2050, republic of south africa. Witwatersrand goldpyriteuraninite deposits do not support a reducing archean atmosphere evolution of early earths atmosphere, hydrosphere, and biosphere constraints from ore deposits origin of hydrothermal fluids and gold mineralization associated with the ventersdorp contact reef, witwatersrand basin, south africa. Schweitzer synopsis the approximately 2800 ma old ventersdorp contact reef is a unique witwatersrand orebody, from which about 6% of the worlds gold production is derived. The growth and concentration of uranium and titanium. The study area and the adjoining witwatersrand basin are well known for its largescale urbanization and industrial activities with substantial water demand. The basin straddles the old provinces of transvaal and the orange free state, and consists of a.
Geological survey fluvial gold placers and basinmargin rotation by eric r. But starting in the 1960s, south africa began to construct its own nuclear weapons program. In the mining areas, deeper groundwater was pumped out at large. The groundwater resources potential and quality characteristics of the greater johannesburg area, was thoroughly assessed using hydrogeochemical and. Witwatersrand conglomerates became analyzed, for the first time, for its pge and au concentrations. Release dates 1 also known as aka 0 release dates uk 1983. The witwatersrand basin is a largely underground geological formation which surfaces in the witwatersrand, south africa. Pdf the witwatersrand basin in south africa has been the focus of gold exploitation for more than 100 years, and the subject of hundreds of. The data repository is an archive and has limited navigation and login functionality. All structured data from the file and property namespaces is available under the creative commons cc0 license. Pyrite zoning as a record of mineralization in the. The witwatersrand basin in south africa is the largest goldfield in the world, with an estimated past production of 50,000 t of gold 40% of world production, and hosts a major uranium resource, with a past production of 1.
Gold mining is currently confined to narrow conglomerate reefs and carbon seams in the upper. Geological survey editorial standards or with north american stratigraphic code. The witwatersrand basin, south africa semantic scholar. Hydrothermal gold mineralization in the witwatersrand basin.
The witwatersrand basin of jr south africa is the bestknown of archean sedimentary basins and contains some of the largest gold reserves in the world. Tectonic instability around the margins of the witwatersrand basin, during the final stages of filling and during deposition of the overlying ventersdorp group, created marginal fault scarps to the basin in places, and yoked basins, into which humid alluvial fans, partly composed of witwatersrand material, were deposited. It is the worlds largest gold and uranium mining basin with the extraction, from more than 120 mines, of 43 500 tons of gold in one century and 73 000 tons of. Details of the selected sites are given in table 1. This is what the miners came for, but soon they will have to dig even deeper. Mafic basement of the mesoarchaean witwatersrand basin. Geotechnical areas associated with the ventersdorp contact. Water balance determination in mine residue deposits. The kopanang waste rock dump is approximately 80 m high and located at no. However, it does show that hydrocarbon liquids may have played an important role in remobilizing uranium from detrital uraninite and concentrating it to potentially economic levels in the witwatersrand basin. In fact, plans are already in place to tap into neighboring gold reefs, which would extend the life of the mine beyond 2040.
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