After an erosional hiatus, the clastic sedimentary rocks and volcanics of the pretoriapostmasburgsegwagwa groups were deposited within the three basins, largely under closedbasin conditions. Pdf upb systematics in carbonates of the postmasburg. These ores are currently being exploited at sishen and beeshoek. Deposition started with the schmidtsdrif subgroup, which is probably oldest in the southwestern part of the basin, and which contains stromatolitic carbonates, siliciclastic sediments and minor lava flows. Geological setting university of the witwatersrand. Although ventersdorp supergroup rocks were encountered in drill holes, the full distribution of these rocks is uncertain due to their weak geophysical.
Application of 3d seismic techniques to evaluate ore. Pdf stratigraphic and geochemical framework of the agouron drill. Kumba iron ores thabazimbi mine exploits predominantly stratabound hematite enrichment along an eastwest trending, ca. These rocks extend westwards beneath the kalahari cover where it is generally only possible. In the neoarchaean intracratonic basin of the kaapvaal craton, between approximately 2640 ma and 2516 ma, two successive stromatolitic carbonate platforms developed. A conceptual model of the geology is shown in figure 1.
The sequence stratigraphic concept and the precambrian rock record. It formed during slow regional cooling and subsidence of the kaapvaal craton sumner and beukes, 2006. Pdf distribution of mafic sills in the transvaal supergroup. The transvaal supergroup contains the makganyene formation glacial diamictite, which represents a lowlatitude global. A geological comparison of the sishen and sishen south.
The intercratonic witwatersrand basin contains the largest known gold deposit on earthdeposit on earth. In this threefold subdivision of the transvaal supergroup, the lowermost sequences eastern. The sedimentary and volcanic rocks of the transvaal supergroup. Molar tooth structures of the neoarchean monteville.
The neoarchean to paleoproterozoic transvaal supergroup overlies the kaapvaal. The transvaal supergroup is a stratigraphic unit in northern south africa and southern. General geology tectonic setting of the transvaal inliers the transvaal supergroup is preserved in two structural basins, the northern capebotswana basin and the transvaal basin fig. Developments in precambrian geology, volume 6, pages 157165.
The carletonville area, transvaal abstract this study involves the stratigraphic analysis of the malmani dolomite subgroup, using subsurface data, in the carletonvi1le area, transvaal, republic of south africa. New observations from the critical transvaal supergroup in southern africa indicate that the goe may have occurred by ca. Gly 163 earth history the transvaal supergroup nils lenhardt earth history transvaal supergroup. Compressional tectonics with re lated thrusting only took place much later in the his tory of the sequence, following deposition of late earlyproterozoic olifantshoek red beds stowe, 1986. Timing and tempo of the great oxidation event pnas.
Reconstructing earths surface oxidation across the. The malmani dolomites are just one rock formation in this sequence, and they are of interest to us because it is in the dolomites that we find the historic lime. Sequence stratigraphic development of the neoarchean transvaal. Structural controls on fe mineralization at thabazimbi. Deconstructing the transvaal supergroup, south africa core. Combining all of these dates, we calculate a weighted mean date of 2,425.
Geochemical evidence for an impact origin for a late. Griqualand west sequence of the transvaal supergroup were investigated by beukes 1980, 1983, who introduced a. It overlies archaean basement rocks, the witwatersrand and ventersdorp supergroups and the. Pdf deconstructing the transvaal supergroup, south. Supergroup include the clastic sediments of the black reef formation, the chemical and clastic sediments of the chuniespoort group, and the clastic sediments and volcanics of the pretoria group. An overview of the geology of the transvaal supergroup. The sequence stratigraphic concept and the precambrian.
The prekaroo geology of the southern portion of the. The palaeoproterozoic transvaal and olifantshoek supergroups of south africa contain some of the earliest hematite. Stratigraphic and geochemical framework of the agouron. Pdf structural analysis and implicit 3d modelling of. These dolomite rocks form part of the transvaal supergroup and were deposited approximately 2 300 rr. The late archaeanearly proterozoic transvaal sequence is preserved within the transvaal, kanye and griqualand west basins, with the 2050 ma bushveld complex intrusive into the upper portion of the succession within the transvaal basin. Pdf two long drill cores through the transvaal supergroup neoarchean paleoproterozoic record the vertical transition from a mixed. The tilting of the transvaal supergroup is the result of the thermal adjustment of the crust following the intrusion of the bushveld complex eriksson et al. Pdf country rock at jwaneng diamond mine provides a rare insight into the deformational history of the transvaal supergroup in southern botswana.
Precambrian research, volume 79, issues 12, page 42. Transvaal supergroup mostly from tombale, 1986 a complete sequence of transvaal supergroup strata is exposed in the southeastern part of the sheet unconformably overlying felsic rocks of the gaborone granite and lobatse group. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Geological map of the transvaal supergroup in south africa and eastern botswana. Ghaap group, transvaal supergroup, of the kaapvaal craton reveals a complex series of.
An overview of the geology of the transvaal sequence and. Chapter 4 palaeoenvironmental setting of ironformations in the depositional basin of the transvaal supergroup, south africa. Penge and kuruman ironformations, transvaal supergroup, south africa. Eriksson b adepartment of geology, rhodes university, grahamstown 6140, south africa bdepartment of geology, university of pretoria, pretoria 0002, south africa. In the transvaal subbasin, the transvaal supergroup is divided into the lower chuniespoort and upper pretoria groups and mostly consists of a succession of chemical and clastic sedimentary rocks. South african suidafrikaanse journal of geology tydskrif vir geologie. Further outwards the younger ventersdorp supergroup mainly. Deconstructing the transvaal supergroup, south africa.
Application of 3d seismic techniques to evaluate ore resources. Remaining gold resources are about 36000 t or 40% of the worlds total gold. The merging of several 3d seismic surveys made clear the gross. Locality map, showing the distribution of the major subdivisions of the transvaal supergroup within the transvaal, griqualand west and kanye basins in south africa and southern botswana. Molar tooth structures of the neoarchean monteville formation, transvaal supergroup, south africa. Since its discovery in 1886 this deposit yielded more thansince its discovery in 1886 this deposit yielded more than 5050 000000 t of gold, or about 40% of all the gold ever mined by mankind. Interestingly, iron formations of the transvaal supergroup are extensively developed in this southern region of the craton, unlike the northern portion where their occurrence is more restricted.
Carbonate petrography, kerogen distribution, and carbon. Nash division of geological and planetary sciences, california. The transvaal basin is one of three sedimentary basins of the transvaal supergroup. The bushveld complex in the context of thethe bushveld. The transvaal supergroup is a supracrustal volcanosedimentary sequence which consists, from the base to the top, of a the protobasinal wolkberg and buffelsfontein groups, b the carbonaceous chuniespoort group, and c the largely pelitic pretoria group. The two basins are separated by a northwest trending arch. A late archean layer rich in sandsized spherules of former silicate melt in the monteville formation transvaal supergroup, south africa has ir concentrations as high as 6. Considerable volumes of groundwater are stored within the dolomitic aquifers of the malma. The transvaal supergroup is a stratigraphic unit in northern south africa and southern botswana, situated on the kaapvaal craton, roughly between 23 and 29 degrees southern latitude and 22 to 30 degrees eastern longitude. The origin of these rocks has been variously attributed to surface processes under an oxygenated atmosphere that post. Constraints on microcrystalline caco 3 precipitation james w. After an erosional hiatus, the clastic sedimentary rocks and volcanics of the pretoriapostmasburgsegwagwa groups were deposited within the three basins, largely under closedbasin. The transvaal supergroup comprises lower and upper successions, namely the chuniespoort and pretoria groups.
This study aims to reevaluate the petrography, geochemistry and geochronology of the mafic. The dolomites, quartzites, and shales of the chuniespoort. Upb systematics in carbonates of the postmasburg group, transvaal supergroup, south africa. This supergroup is divided into the chuniespoort group and the pretoria group. A climate disaster triggered by the evolution of oxygenic photosynthesis robert e. The palaeoproterozoic transvaal supergroup in the northern cape province of south africa is host to the largest known resources of highgrade hematite ore on the southern african continent. The new data suggest that the oxygenation occurred rapidlywithin 1 to 10 million yearsand was followed by. Current correlations between the pretoria and postmasburg groups of the transvaal supergroup are shown to be invalid.
Pdf systematic measured profiles on a regional scale are used to document the distribution. The transvaal supergroup displays three unconformitybounded sequences that surface in two geographically distinct areas the transvaal basin, which circumscribes the bushveld igneous complex, and the griqualand west basin, lying between kimberley and sishen at the western kaapvaal craton rim, extending into southern botswana beneath the kalahari sands as the kanye basin. The groundwater interaction of a deeper lying gold mine. On the northern margin of the transvaal basin, the transvaal supergroup has been folded and imbricated along a portion of the thabazimbimurchison lineament e. Origin of red beds and paleosols in the palaeoproterozoic. Transvaal supergroup, over much of its distribution in the transvaal province of the republic of south africa.
Pdf two long drill cores through the transvaal supergroup neoarcheanpaleoproterozoic record the vertical transition from a mixed. Late archean molecular fossils from the transvaal supergroup record the antiquity of microbial diversity and aerobiosis jacob r. Chapter 2 origin and timing of banded iron formation. The 2,650 to 2,100 myr transvaal supergroup rests unconformably on the volcanosedimentary ventersdorp supergroup fig. Transvaal sedimentation began with predominantly clastic sedimentary rocks black reefvryburg formations followed by carbonate rocks and banded iron formations chuniespoortghaaptaupone groups.
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