Accedi

Bibliografie tematiche / Transvaal Supergroup (South Africa) / Articoli di riviste

Segui questo link per vedere altri tipi di pubblicazioni sul tema: Transvaal Supergroup (South Africa).

Articoli di riviste sul tema "Transvaal Supergroup (South Africa)"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 13 febbraio 2022

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili

Scegli il tipo di fonte:

Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Transvaal Supergroup (South Africa)".

Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.

Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.

Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.

1

Buick, I. S., R. Uken, R. L. Gibson e T. Wallmach. "High-δ13C Paleoproterozoic carbonates from the Transvaal Supergroup, South Africa". Geology 26, n. 10 (1998): 875. http://dx.doi.org/10.1130/0091-7613(1998)026<0875:hcpcft>2.3.co;2.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Moore, John M., Harilaos Tsikos e Stefane Polteau. "Deconstructing the Transvaal Supergroup, South Africa: implications for Palaeoproterozoic palaeoclimate models". Journal of African Earth Sciences 33, n. 3-4 (gennaio 2001): 437–44. http://dx.doi.org/10.1016/s0899-5362(01)00084-7.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Button, A., e R. G. Cawthorn. "Distribution of mafic sills in the Transvaal Supergroup, northeastern South Africa". Journal of the Geological Society 172, n. 3 (19 marzo 2015): 357–67. http://dx.doi.org/10.1144/jgs2014-101.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Lenhardt, N., W. Altermann, F. Humbert e M. de Kock. "Lithostratigraphy of the Palaeoproterozoic Hekpoort Formation (Pretoria Group, Transvaal Supergroup), South Africa". South African Journal of Geology 123, n. 4 (1 dicembre 2020): 655–68. http://dx.doi.org/10.25131/sajg.123.0043.

Testo completo

Abstract (sommario):

Abstract The Palaeoproterozoic Hekpoort Formation of the Pretoria Group is a lava-dominated unit that has a basin-wide extent throughout the Transvaal sub-basin of South Africa. Additional correlative units may be present in the Kanye sub-basin of Botswana. The key characteristic of the formation is its general geochemical uniformity. Volcaniclastic and other sedimentary rocks are relatively rare throughout the succession but may be dominant in some locations. Hekpoort Formation outcrops are sporadic throughout the basin and mostly occur in the form of gentle hills and valleys, mainly encircling Archaean domes and the Palaeoproterozoic Bushveld Complex (BC). The unit is exposed in the western Pretoria Group basin, sitting unconformably either on the Timeball Hill Formation or Boshoek Formation, which is lenticular there, and on top of the Boshoek Formation in the east of the basin. The unit is unconformably overlain by the Dwaalheuwel Formation. The type-locality for the Hekpoort Formation is the Hekpoort farm (504 IQ Hekpoort), ca. 60 km to the west-southwest of Pretoria. However, no stratotype has ever been proposed. A lectostratotype, i.e., the Mooikloof area in Pretoria East, that can be enhanced by two reference stratotypes are proposed herein. The Hekpoort Formation was deposited in a cratonic subaerial setting, forming a large igneous province (LIP) in which short-termed localised ponds and small braided river systems existed. It therefore forms one of the major Palaeoproterozoic magmatic events on the Kaapvaal Craton.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Eriksson, P. G., e W. Altermann. "An overview of the geology of the Transvaal Supergroup dolomites (South Africa)". Environmental Geology 36, n. 1-2 (20 novembre 1998): 179–88. http://dx.doi.org/10.1007/s002540050334.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Knoll, Andrew H., e Nicolas J. Beukes. "Introduction: Initial investigations of a Neoarchean shelf margin-basin transition (Transvaal Supergroup, South Africa)". Precambrian Research 169, n. 1-4 (marzo 2009): 1–14. http://dx.doi.org/10.1016/j.precamres.2008.10.009.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Sumner, Dawn Y., e Samuel A. Bowring. "UPb geochronologic constraints on deposition of the Campbellrand Subgroup, Transvaal Supergroup, South Africa". Precambrian Research 79, n. 1-2 (luglio 1996): 25–35. http://dx.doi.org/10.1016/0301-9268(95)00086-0.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Hartzer, F. J. "Transvaal Supergroup inliers: geology, tectonic development and relationship with the Bushveld complex, South Africa". Journal of African Earth Sciences 21, n. 4 (novembre 1995): 521–47. http://dx.doi.org/10.1016/0899-5362(95)00108-5.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Schroder, S. "Stratigraphic and geochemical framework of the Agouron drill cores, Transvaal Supergroup (Neoarchean-Paleoproterozoic, South Africa)". South African Journal of Geology 109, n. 1-2 (1 giugno 2006): 23–54. http://dx.doi.org/10.2113/gssajg.109.1-2.23.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Smith, Albertus J. B., e Nicolas J. Beukes. "Palaeoproterozoic banded iron formationhosted high-grade hematite iron ore deposits of the Transvaal Supergroup, South Africa". Episodes 39, n. 2 (1 giugno 2016): 269–84. http://dx.doi.org/10.18814/epiiugs/2016/v39i2/95778.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Humbert, F., L. Sonnette, M. O. de Kock, P. Robion, C. S. Horng, A. Cousture e H. Wabo. "Palaeomagnetism of the early Palaeoproterozoic, volcanic Hekpoort Formation (Transvaal Supergroup) of the Kaapvaal craton, South Africa". Geophysical Journal International 209, n. 2 (17 febbraio 2017): 842–65. http://dx.doi.org/10.1093/gji/ggx055.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Simonson, Bruce M., Christian Koeberl, Iain McDonald e Wolf Uwe Reimold. "Geochemical evidence for an impact origin for a Late Archean spherule layer, Transvaal Supergroup, South Africa". Geology 28, n. 12 (dicembre 2000): 1103–6. http://dx.doi.org/10.1130/0091-7613(2000)028<1103:gefaio>2.3.co;2.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Simonson, Bruce M., Christian Koeberl, Iain McDonald e Wolf Uwe Reimold. "Geochemical evidence for an impact origin for a Late Archean spherule layer, Transvaal Supergroup, South Africa". Geology 28, n. 12 (2000): 1103. http://dx.doi.org/10.1130/0091-7613(2000)28<1103:gefaio>2.0.co;2.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Fairey, Brenton, Harilaos Tsikos, Fernando Corfu e Stéphane Polteau. "U–Pb systematics in carbonates of the Postmasburg Group, Transvaal Supergroup, South Africa: Primary versus metasomatic controls". Precambrian Research 231 (luglio 2013): 194–205. http://dx.doi.org/10.1016/j.precamres.2013.03.010.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Fuchs, S., A. E. Williams-Jones e W. J. Przybylowicz. "The origin of the gold and uranium ores of the Black Reef Formation, Transvaal Supergroup, South Africa". Ore Geology Reviews 72 (gennaio 2016): 149–64. http://dx.doi.org/10.1016/j.oregeorev.2015.07.010.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Gutzmmer, J., N. J. Beukes, A. S. E. Kleyenstuber e A. M. Burger. "Magnetic hausmannite from hydrothermally altered manganese ore in the Palaeoproterozoic Kalahari manganese deposit, Transvaal Supergroup, South Africa". Mineralogical Magazine 59, n. 397 (dicembre 1995): 703–16. http://dx.doi.org/10.1180/minmag.1995.059.397.12.

Testo completo

Abstract (sommario):

AbstractHausmannite (Mn3O4), a manganese oxide with a tetragonally distorted spinel structure, is considered to be ferrimagnetic with a very low Curie temperature of 42.5 K. However, strongly magnetic hausmannite has been discovered in some of the hydrothermally altered high-grade manganese ores of the giant Kalahari manganese deposit in South Africa. EDS-electron microprobe analyses indicate magnetic hausmannite to contain on average between 3 and 11.3 wt.% Fe2O3. In contrast non-magnetic hausmannite contains on average about 1–3 wt.% Fe2O3. X-ray powder diffraction analyses reveal small changes in cell dimensions of the magnetic hausmannite related to the high iron content. Mössbauer spectroscopy suggests that all iron is in the trivalent state. Optical microscopy and scanning electron microscopy (electron back-scatter imaging) proved the magnetic hausmannite to be homogeneous in composition, containing only a few minute inclusions of hematite. Magnetic blocking temperatures of the iron-rich hausmannite, approximating the Curie temperature, are of the order of 750 K. It is suggested that the ferrimagnetic state of hausmannite is stabilized and enhanced by replacement of Mn3+ by Fe3+.

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Cabral, Alexandre Raphael, Harilaos Tsikos, Yasuyuki Muramatsu e Tomoko Sekiya. "Iodine and bromine contents in the Palaeoproterozoic Hotazel iron formation, Transvaal Supergroup, South Africa: A reconnaissance study". Geochemistry 71, n. 3 (agosto 2011): 297–301. http://dx.doi.org/10.1016/j.chemer.2011.02.004.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Kesler, Stephen E., Martin Reich e Marlon Jean. "Geochemistry of fluid inclusion brines from Earth's oldest Mississippi Valley-type (MVT) deposits, Transvaal Supergroup, South Africa". Chemical Geology 237, n. 3-4 (marzo 2007): 274–88. http://dx.doi.org/10.1016/j.chemgeo.2006.11.001.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Eriksson, Patrick G., Boris F. F. Reczko e David P. Piper. "An interpretation of boron contents within a Palaeoproterozoic volcano-sedimentary succession: Pretoria Group, Transvaal Supergroup, South Africa". Precambrian Research 78, n. 4 (giugno 1996): 273–87. http://dx.doi.org/10.1016/0301-9268(95)00079-8.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

20

BISHOP, JAMES W., e DAWN Y. SUMNER. "Molar tooth structures of the Neoarchean Monteville Formation, Transvaal Supergroup, South Africa. I: Constraints on microcrystalline CaCO3 precipitation". Sedimentology 53, n. 5 (18 luglio 2006): 1049–68. http://dx.doi.org/10.1111/j.1365-3091.2006.00801.x.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Bau, Michael, e Peter Dulski. "Distribution of yttrium and rare-earth elements in the Penge and Kuruman iron-formations, Transvaal Supergroup, South Africa". Precambrian Research 79, n. 1-2 (luglio 1996): 37–55. http://dx.doi.org/10.1016/0301-9268(95)00087-9.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Strauss, Harald, e Nicolas J. Beukes. "Carbon and sulfur isotopic compositions of organic carbon and pyrite in sediments from the Transvaal Supergroup, South Africa". Precambrian Research 79, n. 1-2 (luglio 1996): 57–71. http://dx.doi.org/10.1016/0301-9268(95)00088-7.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Simonson, Bruce M., Nicolas J. Beukes e Sandra Biller. "Extending the paleogeographic range and our understanding of the Neoarchean Monteville impact spherule layer (Transvaal Supergroup, South Africa)". Meteoritics & Planetary Science 54, n. 10 (11 dicembre 2018): 2217–40. http://dx.doi.org/10.1111/maps.13228.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Johnson, J. E., S. M. Webb, C. B. Condit, N. J. Beukes e W. W. Fischer. "Effects of metamorphism and metasomatism on manganese mineralogy: Examples from the Transvaal Supergroup". South African Journal of Geology 122, n. 4 (1 dicembre 2019): 489–504. http://dx.doi.org/10.25131/sajg.122.0034.

Testo completo

Abstract (sommario):

AbstractManganese-bearing minerals in ancient strata provide a particularly informative record of the redox potentials of ancient Earth surface environments due to the high specificity of species that can oxidize Mn(II). However, little is known about how this sedimentary archive might have been altered by processes occurring long after lithification, including the effects of metamorphism, fluid mobilization, and metasomatism. We investigated Mn mineralization across known metamorphic gradients in the Kaapvaal craton, South Africa, in Archean and early Paleoproterozoic age carbonate-, shale-, and iron formation-bearing marine strata. We sampled contemporaneous strata that record the drowning of the Campbellrand-Malmani carbonate platform and a transition to iron formation deposition in a range of localities, from two metamorphosed (greenschist and above, affected by the intrusion of the Bushveld igneous complex) and four better-preserved (sub-greenschist) deep subsurface drill cores. To evaluate the geochemistry and mineralization tied directly to petrographic textures and cross-cutting relationships, we combined bulk geochemistry with light and electron microscopy and synchrotron microprobe X-ray absorption spectroscopy and imaging to produce Mn speciation maps at the requisite micrometer length scales for these textures. Samples with lesser degrees of post-depositional transformation contained minor amounts of Mn(II) in early diagenetic marine carbonate cements and detrital carbonate grains, while metamorphosed samples typically contained Mn concentrated into a combination of coarse-grained and vein-filling carbonate phases (ankerite, siderite, and rhodochrosite), garnet and amphibole. Chemical imaging analyses of these more metamorphosed samples show that Mn is held by phases and textures that mineralized post-deposition and lithification, demonstrating that Mn was mobilized – at least locally – by metasomatic fluids, although it is difficult to distinguish whether this Mn was original to these strata or was introduced secondarily. Our results confirm that Mn can be mobilized and therefore caution should be applied when interpreting Mn enrichments in sedimentary rocks, especially when Mn enrichment is not geographically extensive and coincides with metamorphic processes.

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Lenhardt, Nils, Patrick G. Eriksson, Octavian Catuneanu e Adam J. Bumby. "Nature of and controls on volcanism in the ca. 2.32–2.06Ga Pretoria Group, Transvaal Supergroup, Kaapvaal Craton, South Africa". Precambrian Research 214-215 (settembre 2012): 106–23. http://dx.doi.org/10.1016/j.precamres.2011.09.012.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

26

BISHOP, JAMES W., DAWN Y. SUMNER e NICOLAS J. HUERTA. "Molar tooth structures of the Neoarchean Monteville Formation, Transvaal Supergroup, South Africa. II: A wave-induced fluid flow model". Sedimentology 53, n. 5 (18 luglio 2006): 1069–82. http://dx.doi.org/10.1111/j.1365-3091.2006.00802.x.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Li, Na, Michaela Frei e Wladyslaw Altermann. "Textural and knowledge-based lithological classification of remote sensing data in Southwestern Prieska sub-basin, Transvaal Supergroup, South Africa". Journal of African Earth Sciences 60, n. 4 (giugno 2011): 237–46. http://dx.doi.org/10.1016/j.jafrearsci.2011.03.002.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

28

van Niekerk, H. S., e N. J. Beukes. "Revised definition/outline of the Kheis Terrane along the western margin of the Kaapvaal Craton and lithostratigraphy of the newly proposed Keis Supergroup". South African Journal of Geology 122, n. 2 (1 giugno 2019): 187–220. http://dx.doi.org/10.25131/sajg.122.0014.

Testo completo

Abstract (sommario):

Abstract The Kheis Province is situated between the Namaqua-Natal Province and the western margin of the Kaapvaal Craton in the Northern Cape Province of South Africa. It has been described as a thin-skinned fold and thrust belt formed between 1800 and 1700 Ma. The lithostratigraphic subdivision of the rock units comprising the Kheis Province has been a source of much controversy. From detailed study of aerial photography and satellite imagery, as well as field-based studies, the outcrop patterns in the Kheis Province and Kaaien Terrane were reinterpreted and a new stratigraphic subdivision is outlined here. It is proposed that the structural Kaaien Terrane and Kheis Province should be combined into the Kheis Terrane and that the rocks occurring in the Kheis Terrane should be grouped together to form the new Keis supergroup, with the basal metaconglomerate of the Mapedi/Gamagara Formation recognised as the regional unconformity between the Keis supergroup and the underlying rocks of the Transvaal Supergroup in the Griqualand West area. The Keis supergroup is subdivided from the base upwards into the Elim-, Olifantshoek-, Groblershoop- and Wilgenhoutsdrif groups. The basal Elim group is composed of the Mapedi/Gamagara- and Lucknow formations. It is overlain with a regional erosional unconformity by the Olifantshoek group, which is made up of the Neylan-, Hartley-, Volop- and Top Dog formations. The Olifantshoek group is conformably overlain by the Groblershoop group which is comprised of three upward coarsening successions:the Faanshoek- and Faansgeluk formations,the Maraisdraai- and Vuilnek formations andthe Opwag- and Skurweberg formations. The Groblershoop group is in turn erosively overlain by the rocks of the Wilgenhoutsdrif Group, which include the basal erosive Groot Drink formation which is overlain by the Zonderhuis- and Leerkrans formations. The lithologies of the Keis supergroup are in faulted contact with the rocks of the younger Areachap Group of the ~1200 Ma Namaqua-Natal Metamorphic Province.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Schaefer, M. O. "Mineral chemistry of sphalerite and galena from Pb-Zn mineralization hosted by the Transvaal Supergroup in Griqualand West, South Africa". South African Journal of Geology 107, n. 3 (1 settembre 2004): 341–54. http://dx.doi.org/10.2113/107.3.341.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Schneiderhan, E. A. "The chemostratigraphy of a Paleoproterozoic MnF- BIF succession -the Voelwater Subgroup of the Transvaal Supergroup in Griqualand West, South Africa". South African Journal of Geology 109, n. 1-2 (1 giugno 2006): 63–80. http://dx.doi.org/10.2113/gssajg.109.1-2.63.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Eroglu, Suemeyya, Ronny Schoenberg, Martin Wille, Nicolas Beukes e Heinrich Taubald. "Geochemical stratigraphy, sedimentology, and Mo isotope systematics of the ca. 2.58–2.50 Ga-old Transvaal Supergroup carbonate platform, South Africa". Precambrian Research 266 (settembre 2015): 27–46. http://dx.doi.org/10.1016/j.precamres.2015.04.014.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Bau, Höhndorf, Dulski e Beukes. "Sources of Rare-Earth Elements and Iron in Paleoproterozoic Iron-Formations from the Transvaal Supergroup, South Africa: Evidence from Neodymium Isotopes". Journal of Geology 105, n. 1 (1997): 121. http://dx.doi.org/10.2307/30079890.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Klein, Cornelis, e Nicolas J. Beukes. "Geochemistry and sedimentology of a facies transition from limestone to iron-formation deposition in the early Proterozoic Transvaal Supergroup, South Africa". Economic Geology 84, n. 7 (1 novembre 1989): 1733–74. http://dx.doi.org/10.2113/gsecongeo.84.7.1733.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Bau, Michael, Axel Höhndorf, Peter Dulski e Nicolas J. Beukes. "Sources of Rare-Earth Elements and Iron in Paleoproterozoic Iron-Formations from the Transvaal Supergroup, South Africa: Evidence from Neodymium Isotopes". Journal of Geology 105, n. 1 (gennaio 1997): 121–29. http://dx.doi.org/10.1086/606152.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Beukes, Nicolas J., e Cornelis Klein. "Geochemistry and sedimentology of a facies transition — from microbanded to granular iron-formation — in the early Proterozoic Transvaal Supergroup, South Africa". Precambrian Research 47, n. 1-2 (aprile 1990): 99–139. http://dx.doi.org/10.1016/0301-9268(90)90033-m.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Eriksson, Patrick G., Boris F. F. Reczko, A. Jaco Boshoff, Ute M. Schreiber, Markus Van der Neut e Carel P. Snyman. "Architectural elements from Lower Proterozoic braid-delta and high-energy tidal flat deposits in the Magaliesberg Formation, Transvaal Supergroup, South Africa". Sedimentary Geology 97, n. 1-2 (giugno 1995): 99–117. http://dx.doi.org/10.1016/0037-0738(95)00004-r.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Luo, Genming, Shuhei Ono, Nicolas J. Beukes, David T. Wang, Shucheng Xie e Roger E. Summons. "Rapid oxygenation of Earth’s atmosphere 2.33 billion years ago". Science Advances 2, n. 5 (maggio 2016): e1600134. http://dx.doi.org/10.1126/sciadv.1600134.

Testo completo

Abstract (sommario):

Molecular oxygen (O2) is, and has been, a primary driver of biological evolution and shapes the contemporary landscape of Earth’s biogeochemical cycles. Although “whiffs” of oxygen have been documented in the Archean atmosphere, substantial O2did not accumulate irreversibly until the Early Paleoproterozoic, during what has been termed the Great Oxygenation Event (GOE). The timing of the GOE and the rate at which this oxygenation took place have been poorly constrained until now. We report the transition (that is, from being mass-independent to becoming mass-dependent) in multiple sulfur isotope signals of diagenetic pyrite in a continuous sedimentary sequence in three coeval drill cores in the Transvaal Supergroup, South Africa. These data precisely constrain the GOE to 2.33 billion years ago. The new data suggest that the oxygenation occurred rapidly—within 1 to 10 million years—and was followed by a slower rise in the ocean sulfate inventory. Our data indicate that a climate perturbation predated the GOE, whereas the relationships among GOE, “Snowball Earth” glaciation, and biogeochemical cycling will require further stratigraphic correlation supported with precise chronologies and paleolatitude reconstructions.

Gli stili APA, Harvard, Vancouver, ISO e altri

38

Mndaweni, S. S. E., S. Naicker e D. Blake. "Hydrostratigraphy of the Malmani Subgroup dolomites within the northeastern escarpment (Limpopo and Mpumalanga, South Africa)". South African Journal of Geology 122, n. 3 (1 settembre 2019): 283–98. http://dx.doi.org/10.25131/sajg.122.0022.

Testo completo

Abstract (sommario):

Abstract The Late Archaean to Early Proterozoic Malmani Subgroup comprises of dolomites and limestones forming part of the Chuniespoort Group within the Transvaal Supergroup, outcropping as an arc structure east of the Pretoria Group along the Limpopo and Mpumalanga escarpment. These rocks form a fractured karst aquifer in the area and have a high degree of heterogeneity and anisotropy. The aquifers are unconfined to semi-confined, with compartmentalisation by dolerite dykes being a possible effect (if the dykes are large and extensive enough) due to the dykes acting as aquitards or barriers to groundwater flow. The contact zones between the dolomite formations and dolerite dykes are usually fractured however, and along with any other faults and fractures result in preferential dolomite dissolution and the development of groundwater flow paths in the area. Borehole yields ranges between 2 to 5 l/s and potentially >10 l/s per borehole in the vicinity of large regional fractures or dolerite intrusions. Groundwater from the Malmani Subgroup generally meets the drinking water quality standards for major constituents and it is of Mg-Ca-HCO3 nature. Groundwater development within this particular hydrostratigraphy is linked to potential well field target zones that take cognisance of various surface water-groundwater interaction affecting surface water discharge rates as well as groundwater over-abstraction concerns. Preliminary results have indicated that given a groundwater potential of 44 hm3/a, the aquifer will be able to support abstractions of up to 29 hm3/a if systematically developed adaptively and could be used and managed conjunctively with surface water to alleviate the pressure on the already stressed Olifants Water Management Area.

Gli stili APA, Harvard, Vancouver, ISO e altri

39

TSIKOS, H., e J. M. MOORE. "Sodic metasomatism in the Palaeoproterozoic Hotazel iron-formation, Transvaal Supergroup, South Africa: implications for fluid-rock interaction in the Kalahari manganese field". Geofluids 5, n. 4 (20 ottobre 2005): 264–71. http://dx.doi.org/10.1111/j.1468-8123.2005.00117.x.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Fischer, W. W., S. Schroeder, J. P. Lacassie, N. J. Beukes, T. Goldberg, H. Strauss, U. E. Horstmann, D. P. Schrag e A. H. Knoll. "Isotopic constraints on the Late Archean carbon cycle from the Transvaal Supergroup along the western margin of the Kaapvaal Craton, South Africa". Precambrian Research 169, n. 1-4 (marzo 2009): 15–27. http://dx.doi.org/10.1016/j.precamres.2008.10.010.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Jahn, Bor-ming, J. Bertrand-Sarfati, N. Morin e J. Macé. "Direct dating of stromatolitic carbonates from the Schmidtsdrif Formation (Transvaal Dolomite), South Africa, with implications on the age of the Ventersdorp Supergroup". Geology 18, n. 12 (1990): 1211. http://dx.doi.org/10.1130/0091-7613(1990)018<1211:ddoscf>2.3.co;2.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Eriksson, Patrick G., e Boris F. F. Reczko. "Contourites associated with pelagic mudrocks and distal delta-fed turbidites in the Lower Proterozoic Timeball Hill Formation epeiric basin (Transvaal Supergroup), South Africa". Sedimentary Geology 120, n. 1-4 (settembre 1998): 319–35. http://dx.doi.org/10.1016/s0037-0738(98)00038-4.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Tsikos, H., J. M. Moore e C. Harris. "Geochemistry of the Palæoproterozoic Mooidraai Formation: Fe-rich limestone as end member of iron formation deposition, Kalahari Manganese Field, Transvaal Supergroup, South Africa". Journal of African Earth Sciences 32, n. 1 (gennaio 2001): 19–27. http://dx.doi.org/10.1016/s0899-5362(01)90016-8.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Reczko, B. F. F., L. A. G. Antoine e P. G. Eriksson. "Three-dimensional computer-assisted basin modelling to generate exploration target areas: an example from the late Archaean-early Proterozoic Transvaal Supergroup, South Africa". Mineralium Deposita 32, n. 4 (9 luglio 1997): 392–400. http://dx.doi.org/10.1007/s001260050105.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Varentsov, I. M., e V. N. Kuleshov. "Rare elements — setting markers of the formation of the manganese and iron ore deposits of Kalahari and Postmasburg areas (South Africa). Communication 1. Kalahari manganese field". Литология и полезные ископаемые, n. 4 (9 luglio 2019): 364–86. http://dx.doi.org/10.31857/s0024-497x20194364-386.

Testo completo

Abstract (sommario):

In manganese ores of the Hotazel Formation (Transvaal supergroup) of the Lower Proterozoic, associated with banded ferrous silicites, high concentrations of a number of rare elements (B, Ge, W, Mo, Cr, Ni, Zn, Cd, Pb, Ag, Bi, As, Sb, Te, Se) were determined. High boron contents in oxide-carbonate ores (manganese lutites) are considered as a consequence of the concentration by chemsorbtion of this element on Mn-carbonates. It is proposed that as a result of hydrothermal transformations, a wide range of ore-forming (mainly Fe, Mn) and rare elements (including REE) was removed from the underlying andesite-basaltic hyaloclastite Ongeluk Formation In manganese ores and ferruginous silicites, typical values of cerium (Ce/Ce* 0.28–1.72) and europium (Eu/Eu* 0.57–16.31) anomalies were established, which may indicate that the initial sediments accumulated in the marginal shallow sea basin with a pronounced oxide surface water layer and close to anoxide conditions near the bottom. Metalliferous (Mn, Fe) sediments of a shallow water basin at different stages of lithogenesis were enriched with europium (positive Eu/Eu*), subjected to metasomatosis (with redistribution of manganese and the formation of manganese carbonates) and, subsequently, regional metamorphism (up to the stage of sericitic green schists).

Gli stili APA, Harvard, Vancouver, ISO e altri

46

de Kock, M. O., D. A. D. Evans, J. L. Kirschvink, N. J. Beukes, E. Rose e I. Hilburn. "Paleomagnetism of a Neoarchean-Paleoproterozoic carbonate ramp and carbonate platform succession (Transvaal Supergroup) from surface outcrop and drill core, Griqualand West region, South Africa". Precambrian Research 169, n. 1-4 (marzo 2009): 80–99. http://dx.doi.org/10.1016/j.precamres.2008.10.015.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Wiggering, Hubert, e Nicolas J. Beukes. "Petrography and geochemistry of a 2000–2200-Ma-old hematitic Paleo-alteration profile on Ongeluk basalt of the Transvaal supergroup, Griqualand West, South Africa". Precambrian Research 46, n. 3 (febbraio 1990): 241–58. http://dx.doi.org/10.1016/0301-9268(90)90004-a.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Sumner, D. Y. "Carbonate precipitation and oxygen stratification in late Archean seawater as deduced from facies and stratigraphy of the Gamohaan and Frisco formations, Transvaal Supergroup, South Africa". American Journal of Science 297, n. 5 (1 maggio 1997): 455–87. http://dx.doi.org/10.2475/ajs.297.5.455.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Beukes, Nicolas J., Cornelis Klein, Alan J. Kaufman e J. M. Hayes. "Carbonate petrography, kerogen distribution, and carbon and oxygen isotope variations in an early Proterozoic transition from limestone to iron-formation deposition, Transvaal Supergroup, South Africa". Economic Geology 85, n. 4 (1 luglio 1990): 663–90. http://dx.doi.org/10.2113/gsecongeo.85.4.663.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Land, Jarred S., Harilaos Tsikos, David Cousins, George Luvizotto e Thomas Zack. "Origin of red beds and paleosols in the Palaeoproterozoic Transvaal and Olifansthoek Supergroups of South Africa: provenanceversusmetasomatic controls". Geological Journal 53, n. 1 (25 gennaio 2017): 191–202. http://dx.doi.org/10.1002/gj.2885.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

Offriamo sconti su tutti i piani premium per gli autori le cui opere sono incluse in raccolte letterarie tematiche. Contattaci per ottenere un codice promozionale unico!