Geochemical evidence for an impact origin for a late. 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. 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. 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. Although ventersdorp supergroup rocks were encountered in drill holes, the full distribution of these rocks is uncertain due to their weak geophysical. Remaining gold resources are about 36000 t or 40% of the worlds total gold. 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. Pdf deconstructing the transvaal supergroup, south. An overview of the geology of the transvaal sequence and.
Pdf structural analysis and implicit 3d modelling of. The sequence stratigraphic concept and the precambrian rock record. Origin of red beds and paleosols in the palaeoproterozoic. Developments in precambrian geology, volume 6, pages 157165. 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. 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. Late archean molecular fossils from the transvaal supergroup record the antiquity of microbial diversity and aerobiosis jacob r. The prekaroo geology of the southern portion of the. 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. Deconstructing the transvaal supergroup, south africa.
Structural controls on fe mineralization at thabazimbi. The intercratonic witwatersrand basin contains the largest known gold deposit on earthdeposit on earth. 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. Molar tooth structures of the neoarchean monteville. These dolomite rocks form part of the transvaal supergroup and were deposited approximately 2 300 rr. Griqualand west sequence of the transvaal supergroup were investigated by beukes 1980, 1983, who introduced a. The new data suggest that the oxygenation occurred rapidlywithin 1 to 10 million yearsand was followed by. Precambrian research, volume 79, issues 12, page 42. 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. 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.
Pdf country rock at jwaneng diamond mine provides a rare insight into the deformational history of the transvaal supergroup in southern botswana. Application of 3d seismic techniques to evaluate ore resources. Constraints on microcrystalline caco 3 precipitation james w. These rocks extend westwards beneath the kalahari cover where it is generally only possible. Ghaap group, transvaal supergroup, of the kaapvaal craton reveals a complex series of.
Geological map of the transvaal supergroup in south africa and eastern botswana. The origin of these rocks has been variously attributed to surface processes under an oxygenated atmosphere that post. 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. 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. Deconstructing the transvaal supergroup, south africa core. The palaeoproterozoic transvaal and olifantshoek supergroups of south africa contain some of the earliest hematite. 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. Pdf upb systematics in carbonates of the postmasburg. The bushveld complex in the context of thethe bushveld. Pdf systematic measured profiles on a regional scale are used to document the distribution. A climate disaster triggered by the evolution of oxygenic photosynthesis robert e. The 2,650 to 2,100 myr transvaal supergroup rests unconformably on the volcanosedimentary ventersdorp supergroup fig. This supergroup is divided into the chuniespoort group and the pretoria group. Stratigraphic and geochemical framework of the agouron.
New observations from the critical transvaal supergroup in southern africa indicate that the goe may have occurred by ca. Carbonate petrography, kerogen distribution, and carbon. Transvaal supergroup, over much of its distribution in the transvaal province of the republic of south africa. Molar tooth structures of the neoarchean monteville formation, transvaal supergroup, south africa. The transvaal supergroup contains the makganyene formation glacial diamictite, which represents a lowlatitude global. 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. Further outwards the younger ventersdorp supergroup mainly. It formed during slow regional cooling and subsidence of the kaapvaal craton sumner and beukes, 2006. Considerable volumes of groundwater are stored within the dolomitic aquifers of the malma. Current correlations between the pretoria and postmasburg groups of the transvaal supergroup are shown to be invalid. 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. 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. Sequence stratigraphic development of the neoarchean transvaal.
Reconstructing earths surface oxidation across the. The neoarchean to paleoproterozoic transvaal supergroup overlies the kaapvaal. Gly 163 earth history the transvaal supergroup nils lenhardt earth history transvaal supergroup. An overview of the geology of the transvaal supergroup. Combining all of these dates, we calculate a weighted mean date of 2,425. Chapter 4 palaeoenvironmental setting of ironformations in the depositional basin of the transvaal supergroup, south africa. Transvaal sedimentation began with predominantly clastic sedimentary rocks black reefvryburg formations followed by carbonate rocks and banded iron formations chuniespoortghaaptaupone groups. In this threefold subdivision of the transvaal supergroup, the lowermost sequences eastern. The transvaal supergroup comprises lower and upper successions, namely the chuniespoort and pretoria groups. Hematite occurances on the sishen south exploration project some 65 km south of sishen mine, are at. A conceptual model of the geology is shown in figure 1.
Pdf stratigraphic and geochemical framework of the agouron drill. On the northern margin of the transvaal basin, the transvaal supergroup has been folded and imbricated along a portion of the thabazimbimurchison lineament e. Kumba iron ores thabazimbi mine exploits predominantly stratabound hematite enrichment along an eastwest trending, ca. The two basins are separated by a northwest trending arch. South african suidafrikaanse journal of geology tydskrif vir geologie. Nash division of geological and planetary sciences, california. Pdf two long drill cores through the transvaal supergroup neoarchean paleoproterozoic record the vertical transition from a mixed. After an erosional hiatus, the clastic sedimentary rocks and volcanics of the pretoriapostmasburgsegwagwa groups were deposited within the three basins, largely under closedbasin conditions. Chapter 2 origin and timing of banded iron formation.
The transvaal supergroup is a stratigraphic unit in northern south africa and southern. The groundwater interaction of a deeper lying gold mine. Eriksson b adepartment of geology, rhodes university, grahamstown 6140, south africa bdepartment of geology, university of pretoria, pretoria 0002, south africa. The sedimentary and volcanic rocks of the transvaal supergroup. Pdf distribution of mafic sills in the transvaal supergroup. The dolomites, quartzites, and shales of the chuniespoort. 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 neoarcheanpaleoproterozoic record the vertical transition from a mixed. The transvaal basin is one of three sedimentary basins of the transvaal supergroup. Penge and kuruman ironformations, transvaal supergroup, south africa. These ores are currently being exploited at sishen and beeshoek. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Geological setting university of the witwatersrand.
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